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Articles de revues sur le sujet "Inhibitory effect on mycelial development"
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Lee, Hee-Kyung, On-you Choi, Hyun-suk Choi, Myung-ja Lee et Kwan-jong Yu. « 기능성차 개발을 위한 아위느타리 버섯 발효액 추출물의 아세틸콜린에스테라제 저해활성에 관한 연구 ». Association for International Tea Culture 58 (31 décembre 2022) : 135–59. http://dx.doi.org/10.21483/qwoaud.58..202212.135.
Texte intégralRésumé :
This study was to investigate the inhibitory activity of oxidation and acetylcholinesterase using acetone, hexane, ethyl acetate, hot water and ethanol extracts of mycelia obtained from submerged culture from Pleurotus eryngii (DC. ex Fr.) Quel. var. ferulae Lanzi for function tea development. Among various solvent extracts on the oxidation inhibitory activity, the ethanol extract obtained 66.18% of the maximum inhibitory activity. In the case of acetylcholinesterase inhibitory activity, the hot water extract obtained 13.24% of the maximum inhibitory activity. The maximum inhibitory activity of acetylcholinesterase was obtained 17.36% at 40℃ of extract temperature. The maximum inhibitory activity of oxidation was obtained 63.28% at 60℃. The oxidation inhibitory activity was increased from 50.63 to 60.17% when extract time was increased from 2hr to 4hr at 60℃. On the other hand, in the case of over 6hr of extract time, it was decreased to 55.43% at 12hr of extract time. Thermal and pH of acetylcholinesterase inhibitor were stable at 10-30℃ and pH 5.0 to 9.0. As a result, it is considered that this pretreatment effect is effective in promoting inhibitory activity of acetylcholinesterase and oxidation using P. eryngii (DC. ex Fr.) Quel. var. ferulae Lanzi mycelia.
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Ye, Huochun, Qin Wang, Fadi Zhu, Gang Feng, Chao Yan et Jing Zhang. « Antifungal Activity of Alpha-Mangostin against Colletotrichum gloeosporioides In Vitro and In Vivo ». Molecules 25, no 22 (16 novembre 2020) : 5335. http://dx.doi.org/10.3390/molecules25225335.
Texte intégralRésumé :
We investigated alpha-mangostin (α-mangostin, α-MG), a xanthone natural product extracted from the pericarp of mangosteen (Garcinia mangostana), for its antifungal activities and possible mechanism against Colletotrichum gloeosporioides, which causes mango anthracnose. The results demonstrated that α-MG had a relatively high in vitro inhibitory activity against C. gloeosporioides among 20 plant pathogenic fungi. The median effective concentration (EC50) values of α-MG against mycelial growth were nearly 10 times higher than those of spore germination inhibition for both strains of C. gloeosporioides, the carbendazim-sensitive (CBD-s) and carbendazim-resistant (CBD-r). The results suggested that α-MG exhibited a better inhibitory effect on spore germination than on the mycelial growth of C. gloeosporioides. Further investigation indicated that the protective effect could be superior to the therapeutic effect for mango leaves for scab development. The morphological observations of mycelium showed that α-MG caused the accumulation of dense bodies. Ultrastructural observation further revealed that α-MG caused a decrease in the quantity and shape of the swelling of mitochondria in the mycelium cells of C. gloeosporioides. In addition, bioassays disclosed that the inhibitory activity of α-MG on spore germination was reduced by adding exogenous adenosine triphosphate (ATP). These results suggested that the mode of action of α-MG could be involved in the destruction of mitochondrial energy metabolism. The current study supports α-MG as a natural antifungal agent in crop protection.
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Reis, Ana Carolina Botelho dos, et Júlia Ronzella Ottoni. « Antifungal activity of homeopathic medicines against the white mold causing agent Sclerotinia sclerotiorum ». Acta Scientiarum. Biological Sciences 43 (25 octobre 2021) : e56548. http://dx.doi.org/10.4025/actascibiolsci.v43i1.56548.
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White mold disease, caused by fungus Sclerotinia sclerotiorum (Lib.) de Bary., is a disease hard to control due to the high amount of sclerotia produced, which guarantees its survival in the soil for years leading to significant yield losses. Alternative techniques to control the pathogen have been researched, including homeopathy. The present work aimed to evaluate the in vitro antifungal effect of homeopathic medicines on S. sclerotiorum mycelial growth. Homeopathic medicines Sulphur, fungal sclerotium Nosode and Calcarea carbonica, in 30CH, 200CH and 1000CH dynamizations were tested. Assays were carried out in a completely randomized design, with four repetitions. Experiments were performed through the addition of homeopathic medicines on the surface of plates containing culture medium, followed by insertion of a disc containing fungus mycelia and incubation. Control treatment received no homeopathic medicine. The mycelial progression was monitored by seven halo diameter measurements during experiment period. All homeopathic medicines tested and their dynamizations were able to inhibit partially the development of the fungus. Calcarea carbonica at the dynamization of 1000 CH showed the best inhibitory effect on S. sclerotiorum, which under its effect produced a mycelial halo 40% smaller than the control treatment.
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Saniewska, Alicja. « Effect of polyamine biosynthesis inhibitors on in vitro growth of Phyllosticta antirrhini Sydow and on the infection of Antirrhinum majus L. by the pathogen ». Acta Agrobotanica 52, no 1-2 (2013) : 11–18. http://dx.doi.org/10.5586/aa.1999.002.
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Polyamine biosynthesis inhibitors, DL-α-difluromethylornithine (DFMO) and DL-α-difluromethylarginine (DFMA) at concentrations of 1,0 and 3,0 mM greatly inhibited mycelial growth of <em>Phyllosticta antirrhini</em> on Czapek Dox Agar (CDA). Putrescine at the concentration of 1,0 mM completely reversed the inhibitory effect of DFMO but only partially that of DFMA. Both polyamine biosynthesis inhibitors at concentrations 1,0 and 3,0 mM applied preventively and curatively strongly inhibited the development of the pathogen on snapdragon leaves.
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Wang, Yaochen, Keke Wei, Xiaobin Han, Donglin Zhao, Yanfen Zheng, Jianmin Chao, Jianyu Gou, Fanyu Kong et Cheng-Sheng Zhang. « The Antifungal Effect of Garlic Essential Oil on Phytophthora nicotianae and the Inhibitory Component Involved ». Biomolecules 9, no 10 (21 octobre 2019) : 632. http://dx.doi.org/10.3390/biom9100632.
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This study explored the chemical compositions of garlic essential oil, the inhibitory activity of garlic essential oil and diallyl disulfide (DADS) against Phytophthora nicotianae, and the effects on mycelial plasma membrane permeability and P. nicotianae inhibition. In total, 29 compounds were detected in garlic essential oil, of which 26 were detected by gas chromatography‒mass spectrometry (GC-MS) and 21 by headspace solid-phase microextraction (HS-SPME) GC-MS. DADS (60.12% and 19.09%) and trisulfide di-2-propenyl (14.18% and 17.98%) were the major components identified by HS-SPME GC-MS and GC-MS analysis, respectively. Half-inhibitory concentration (Ec50, antagonism) and minimum inhibitory concentration (MIC, fumigation) of DADS against P. nicotianae were 150.83 μL/L and 20 μL/L, respectively, while Ec50 of garlic essential oil was 1108.25 μL/L. Mycelial membrane permeability gradually increased in a concentration-dependent manner, and cell death increased at 450 μL/L DADS. Furthermore, DADS treatment significantly reduced the incidence of tobacco black shank and the number of P. nicotianae pathogens in rhizosphere soil. DADS also promoted root development of tobacco seedlings at low concentrations, which was inhibited at high concentrations. Therefore, DADS may play an important role in the antifungal effect against P. nicotianae by destroying mycelial cell membrane integrity, causing an increase in cell membrane permeability, and leading to cell death.
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Padgett, Merilark, et Janice C. Morrison. « Changes in Grape Berry Exudates during Fruit Development and Their Effect on Mycelial Growth of Botrytis cinerea ». Journal of the American Society for Horticultural Science 115, no 2 (mars 1990) : 269–73. http://dx.doi.org/10.21273/jashs.115.2.269.
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Grape berries (Vitis vinifera L., `Thompson Seedless') exuded a variety of compounds through the cuticle and epicuticular wax layer onto the berry surface. The composition of the exudate changed through the course of the growing season. Phenolic compounds and malic acid were in relatively high concentrations in grape berry exudates after bloom, but were low in exudates from mature fruit. The rate of decrease of phenols and malic acid was more rapid during the early stage of berry growth than during the ripening period. Sugar and potassium concentrations in the berry exudates were low at bloom, but increased rapidly in the later stages of ripening. Water extracts of berry exudates contained sugars, malic acid, potassium, and sodium. The water extracts promoted mycelial growth of Botrytis cinerea Pers. Ethanol and ether extracts contained phenols and lipids. These fractions from fruit sampled in the first 3 weeks after bloom strongly inhibited mycelial growth. The inhibitory effect of these fractions decreased later in the season.
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Mohammed, Sabah R., Elsayed M. Zeitar et Ivan D. Eskov. « Inhibition of Mycelial Growth of Rhizoctonia Solani by Chitosan in vitro and in vivo ». Open Agriculture Journal 13, no 1 (20 décembre 2019) : 156–61. http://dx.doi.org/10.2174/1874331501913010156.
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Objective: Evaluate the antifungal effect of chitosan against Rhizoctonia solani in vitro and the possible mechanisms of its induced activity in potato tubers to control black scurf disease. Methods: The in vitro influence of chitosan at different concentrations on mycelial growth of R. solani was tested by using the poisoned food technique in PDA medium. The effect of these concentrations on the development of lesion diameters in tubers inoculated with R. solani mycelium was assayed for 30 days. The concentration that showed the greatest inhibitory effect on lesion diameters was tested to assess the induced activity of defense-related enzymes in the infected tubers. Results: In the poisoned food technique, chitosan at 1% completely inhibited the growth of R. solani mycelium. In vivo tests showed that chitosan treatment at 0.5% effectively controlled the black scurf in tubers inoculated with R. solani mycelium. Chitosan increased the activities of defense-related enzymes such as Peroxidase (POD), Polyphenol Oxidase (PPO) and Phenylalanine Ammonia-lyase (PAL) in treated tubers of tested cultivars. Conclusion: This work demonstrated that chitosan directly inhibited the growth of R. solani, and potentially elicited defense reaction in potato tubers.
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Tian, Jun, Xiaobin Zeng, Hong Zeng, Zhaozhong Feng, Xiangmin Miao et Xue Peng. « Investigations on the Antifungal Effect of Nerol againstAspergillus flavusCausing Food Spoilage ». Scientific World Journal 2013 (2013) : 1–8. http://dx.doi.org/10.1155/2013/230795.
Texte intégralRésumé :
The antifungal efficacy of nerol (NEL) has been proved againstAspergillus flavusby usingin vitroandin vivotests. The mycelial growth ofA. flavuswas completely inhibited at concentrations of 0.8 μL/mL and 0.1 μL/mL NEL in the air at contact and vapor conditions, respectively. The NEL also had an evident inhibitory effect on spore germination inA. flavusalong with NEL concentration as well as time-dependent kinetic inhibition. The NEL presented noticeable inhibition on dry mycelium weight and synthesis of aflatoxin B1(AFB1) byA. flavus, totally restraining AFB1production at 0.6 μL/mL. In real food system, the efficacy of the NEL on resistance to decay development in cherry tomatoes was investigatedin vivoby exposing inoculated and control fruit groups to NEL vapor at different concentration. NEL vapors at 0.1 μL/mL air concentration significantly reduced artificially contaminatedA. flavusand a broad spectrum of fungal microbiota. Results obtained from presented study showed that the NEL had a great antifungal activity and could be considered as a benefit and safe tool to control food spoilage.
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Adebayo, Oyeboade, André Bélanger et Shahrokh Khanizadeh. « Variable inhibitory activities of essential oils of three Monarda species on the growth of Botrytis cinerea ». Canadian Journal of Plant Science 93, no 6 (novembre 2013) : 987–95. http://dx.doi.org/10.4141/cjps2013-044.
Texte intégralRésumé :
Adebayo, O., Bélanger, A. and Khanizadeh, S. 2013. Variable inhibitory activities of essential oils of three Monarda species on the growth of Botrytis cinerea . Can. J. Plant Sci. 93: 987–995. The antifungal effects of the essential oils of three Monarda species (Monarda didyma L., M. fistulosa L., and M. didyma var. 80-1A L.) were evaluated against Botrytis cinerea Pers.: Fr. The inhibitory effects of the volatile and contact phases of the essential oils were determined on hyphae and spores. The effects of the essential oils on the morphological structures of hyphae were studied under light microscopy. All the three tested essential oils types had inhibitory effects on both mycelia and spores as follows, in descending order of effectiveness: M. didyma > M. didyma var. 80-1A > M. fistulosa. For all essential oils, the volatile phase effects were more toxic on fungal growth than the contact phase effects. All the essential oils in the contact studies achieved complete inhibition of mycelial growth and spore germination at 819.2 µg mL−1 of ethanol and Tween 20 mixture. In the volatile studies, however, complete mycelial inhibition was achieved with M. didyma and M. didyma var. 80-1A at 0.1 µg mL−1 air and with M. fistulosa at 0.2 µg mL−1 air. Spore germination was inhibited at 0.05 µg mL−1 air with M. didyma and 0.2 µg mL−1 air with both M. didyma var. 80-1A and M. fistulosa. This study demonstrated that these essential oils are promising potential antifungal agents that could be used in the development of biofungicide alternatives to synthetic fungicides against B. cinerea.
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Laugale, Valda, Līga Jankevica, Ineta Samsone, Jūlija Haļimona, Rita Sešķēna, Zane Metla, Jānis Lepsis, Regina Rancane et Māris Daugavietis. « Preliminary Studies on Development of a New Environmentally Friendly Plant Protection Product Against Grey Mould ». Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences 67, no 2 (1 août 2013) : 199–202. http://dx.doi.org/10.2478/prolas-2013-0033.
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The development of new environmentally friendly plant protection products against grey mould disease (caused by Botrytis cinerea Pers.) was started in 2010. In the Latvian State Forest Research Institute “Silava”, production of coniferous biomass extracts using different solvents for extraction was performed. During 2010-2011, several laboratory investigations were carried out in the Institute of Biology, University of Latvia. Effectiveness of pine (Pinus sylvestris) and spruce (Picea abies) biomass extracts against Botrytis cinerea was tested. On the basis of coniferous extracts, 11 formulations were created and characterised. The effect of the formulations on mycelial growth of B. cinerea test cultures was tested using the fungal radial growth test. All formulations had inhibitory effect on mycelium growth (inhibition rate over 50%) at concentration 20 g L-1 in medium. The impact of formulations on plants after spraying was evaluated using in vitro propagated strawberry plants. Chlorophyll content and chlorophyll fluorescence were estimated. Extracts did not show negative effect on the chlorophyll content and fluorescence of strawberry leaves. Field investigations on strawberry (Fragaria × ananassa Duch.) ‘Senga Sengana’ and primocane raspberry (Rubus idaeus) ‘Gerakl’ were conducted in the Pûre Horticultural Research Centre in 2011. None of tested the coniferous biomass extract formulations showed higher effectiveness than fungicide Signum® (pyraclostrobin 6.7%+ boscalid 26.7%, BASF).
Thèses sur le sujet "Inhibitory effect on mycelial development"
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Ferenz, Hans-Jörg, et Martin G. Peter. « The inhibitory effect of sinefungin on juvenile hormone biosynthesis and development in locusts ». Universität Potsdam, 1987. http://opus.kobv.de/ubp/volltexte/2008/1681/.
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The antibiotic fungal metabolite sinefungin is a potent inhibitor of S-adenosylmethionine-acceptor methyltransferases. Its effect on insect metabolism and especially on corpora allata farnesoic acid methyltransferase, which catalyzes the penultimate step of juvenile hormone biosynthesis, was investigated in Locusta migratoria. Injection of sinefungin results in a delay of imaginal molt and in suppression of ovary development. Isolated corpora allata are unable to synthesize juvenile hormone III in the presence of more than 1.0 mM sinefungin. In a cell-free system containing the S-adenosylmethionine-dependent farnesoic acid methyltransferase from corpora allata sinefungin is a competitive inhibitor of the synthesis of methylfarnesoate with Ki of 1 μM.
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VIZZUSO, CELESTE. « Interazioni antagonistiche in vitro fra Phomopsis quercina e funghi endofitici di specie quercine ». Doctoral thesis, 2007. http://hdl.handle.net/2158/572497.
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Hasan, Sascha [Verfasser]. « Leukemia inhibitory factor enhances neurogenin's pro-neural effect during mouse cortical development / von Sascha Hasan ». 2007. http://d-nb.info/986645168/34.
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« The inhibitory effect of trans fatty acids on maternal and neonatal essential fatty acid metabolism ». 1997. http://library.cuhk.edu.hk/record=b5889120.
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by Kwan Kwok Yiu.Thesis (M.Phil.)--Chinese University of Hong Kong, 1997.
Includes bibliographical references (leaves 145-155).
Acknowledgment --- p.i
Abstract --- p.ii
List of Tables --- p.vii
List of Figures --- p.x
List of Abbreviations --- p.xii
Chapter Chapter 1 --- Literature review
Chapter 1.1 --- Historical background --- p.1
Chapter 1.2 --- Chemistry of trans and cis fatty acids --- p.3
Chapter 1.3 --- Dietary source of trans fatty acids --- p.6
Chapter 1.4 --- Consumption of trans fatty acids among Western countries --- p.9
Chapter 1.5 --- Current health concern for excessive intake of trans fatty acids --- p.10
Chapter 1.6 --- Metabolism of trans fatty acids --- p.13
Chapter 1.6.1 --- Absorption --- p.15
Chapter 1.6.2 --- Oxidation --- p.15
Chapter 1.6.3 --- Incorporation --- p.16
Chapter 1.6.4 --- Selectivity --- p.17
Chapter 1.7 --- Impact of trans fatty acids on essential fatty acid metabolism --- p.19
Chapter 1.8 --- Desaturation and elongation of trans fatty acids --- p.21
Chapter 1.9 --- Trans fatty acids and neonatal growth --- p.23
Chapter Chapter 2 --- Amount of trans fatty acids in Hong Kong fast foods
Chapter 2.1 --- Introduction --- p.25
Chapter 2.2 --- Objective --- p.25
Chapter 2.3 --- Materials and methods --- p.26
Chapter 2.4 --- Results --- p.27
Chapter 2.5 --- Discussion --- p.31
Chapter Chapter 3 --- Cross-cultural study of trans fatty acids in human milk
Chapter 3.1 --- Introduction --- p.35
Chapter 3.2 --- Objective --- p.35
Chapter 3.3 --- Materials and methods --- p.36
Chapter 3.4 --- Results
Chapter 3.4.1 --- Dietary information --- p.38
Chapter 3.4.2 --- Fatty acid composition of Chinese and Canadian human milk --- p.40
Chapter 3.4.3 --- Difference between Chinese and Canadian human milk --- p.40
Chapter 3.4.4 --- Difference between Hong Kong and Chongqing Chinese human milk --- p.43
Chapter 3.4.5 --- The change in milk fat and LCPUFA as lactation progresses --- p.43
Chapter 3.5 --- Discussion
Chapter 3.5.1 --- Trans fatty acids in human milk --- p.46
Chapter 3.5.2 --- Content of LCPUFA in human milk --- p.47
Chapter 3.5.3 --- Content of 18:2n-6 in human milk --- p.48
Chapter 3.5.4 --- Fat content in Hong Kong and Chongqing Chinese human milk --- p.49
Chapter 3.6 --- Conclusion --- p.50
Chapter Chapter 4 --- Trans fatty acids and maternal and neonatal essential fatty acid metabolism
Chapter 4.1 --- Introduction --- p.51
Chapter 4.2 --- Objectives --- p.53
Chapter 4.3 --- Materials and methods --- p.53
Chapter 4.4 --- Results
Chapter 4.4.1 --- Experiment1
Chapter 4.4.1.1 --- Relationship between the trans fatty acids in maternal diet and those in milk --- p.64
Chapter 4.4.1.2 --- Relationship between the trans fatty acids in maternal diet and those in neonatal liver --- p.64
Chapter 4.4.1.3 --- Content of 20:4n-6 in milk and in neonatal liver relative to that in maternal diet --- p.72
Chapter 4.4.2 --- Experiment2
Chapter 4.4.2.1 --- Amount of trans fatty acids in rat milk --- p.75
Chapter 4.4.2.2 --- Trans fatty acids in rat liver phospholipids --- p.75
Chapter 4.4.2.3 --- Linoleic acid (18:2n-6) content in rat and its relation to maternal diets --- p.86
Chapter 4.4.2.4 --- Content of 20:4n-6 in rat milk --- p.86
Chapter 4.4.2.5 --- Content of20:4n-6 in rat liver --- p.89
Chapter 4.4.2.6 --- Suppression of the synthesis of 20:4t isomers in maternal and neonatal liver --- p.89
Chapter 4.5 --- Discussion
Chapter 4.5.1 --- Relationship between fatty acid composition of diet and that of milk --- p.93
Chapter 4.5.2 --- 20:4n-6 in rat milk --- p.95
Chapter 4.5.3 --- Transfer of trans fatty acids from maternal diet to neonatal liver phospholipids --- p.98
Chapter 4.5.4 --- The inhibitory effect of trans fatty acids on synthesis of 20:4n-6 in neonatal liver --- p.99
Chapter 4.5.5 --- Effect of 18:2n-6 supplement on 20:4n-6 level of neonatal liver --- p.101
Chapter 4.5.6 --- Suppression of 18:2n-6 supplement on synthesis of 20:4t isomers --- p.101
Chapter 4.6 --- Conclusion --- p.104
Chapter Chapter 5 --- Accumulation and turnover of trans fatty acids
Chapter 5.1 --- Introduction --- p.105
Chapter 5.2 --- Objective --- p.105
Chapter 5.3 --- Materials and methods --- p.106
Chapter 5.4 --- Results
Chapter 5.4.1 --- Accumulation of trans fatty acids in liver and adipose tissue --- p.108
Chapter 5.4.2 --- Selectivity of individual 18:2 trans isomersin liver and adipose tissue --- p.112
Chapter 5.4.3 --- Turnover of trans fatty acids --- p.112
Chapter 5.4.4 --- Accumulation and turnover of 18:lt in brain --- p.115
Chapter 5.5 --- Discussion
Chapter 5.5.1 --- Accumulation of trans fatty acids in liver and adipose tissue --- p.120
Chapter 5.5.2 --- Turnover of trans fatty acids --- p.122
Chapter 5.5.3 --- Accumulation and turnover of trans fatty acidsin brain --- p.124
Chapter 5.6 --- Conclusion --- p.125
Chapter Chapter 6 --- In vivo Oxidation of trans fatty acids in rat
Chapter 6.1 --- Introduction --- p.126
Chapter 6.2 --- Objective --- p.127
Chapter 6.3 --- Materials and methods --- p.127
Chapter 6.4 --- Results --- p.129
Chapter 6.4.1 --- Apparent oxidation of saturated fatty acids --- p.136
Chapter 6.4.2 --- Apparent oxidation of 18:lt relative to 18:ln-9 --- p.136
Chapter 6.4.3 --- Oxidation of 18:2t isomers relative to 18:2n-6 --- p.137
Chapter 6.4.4 --- Effect of 18:2n-6 supplement in PHCO diet on oxidation per se --- p.137
Chapter 6.5 --- Discussion --- p.138
Chapter 6.5.1 --- Oxidation of 18:lt and 18:2t isomers --- p.139
Chapter 6.5.2 --- Effect of 18:2n-6 supplement on oxidation per se --- p.140
Chapter 6.6 --- Conclusion --- p.141
General conclusion --- p.142
References --- p.145
Livres sur le sujet "Inhibitory effect on mycelial development"
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Marchand, Serge. The milestone effect of DNIC in our understanding of pain. Sous la direction de Paul Farquhar-Smith, Pierre Beaulieu et Sian Jagger. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198834359.003.0039.
Texte intégralRésumé :
While thousands of articles are published each year on pain, only a few have such a major impact on the understanding of pain mechanisms as the landmark paper discussed in this chapter; published by Le Bars and colleagues in 1979, it introduced the concept of diffuse noxious inhibitory control (DNIC; also called diffuse noxious inhibition) mechanisms. Although this work is more than three decades old, it still has a major influence on both the understanding of pain mechanisms and the development of clinical approaches. It is known that apparently similar pain may be caused by different mechanisms: one may be caused by amplified excitatory mechanisms while the other may be related to a deficit of endogenous pain modulation, such as DNIC or conditioned pain modulation (or CPM); these will not respond to the same treatment. The work by Le Bars and colleagues provided a new understanding of mechanisms underlying pain.
Chapitres de livres sur le sujet "Inhibitory effect on mycelial development"
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Golly, M. K., H. Ma, D. Liu, D. Yating, A. S. Amponsah et K. A. Duodu. « Ultrasound-Assisted Alkaline Treatment Effect on Antioxidant and ACE-Inhibitory Potential of Walnut for Sustainable Industrialization ». Dans Sustainable Education and Development – Sustainable Industrialization and Innovation, 1143–63. Cham : Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-25998-2_89.
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Kobori, Shozo, Takeshi Takahashi, Shoko Kodama, Toru Takemura, Takeshi Matsumura, Masakazu Sakai, Takayuki Sasahara et Motoaki Shichiri. « Inhibitory Effect of HMG-CoA Reductase Inhibitors for the Development and Progression of Intimal-medial Thickness in Carotid Artery in Type 2 Diabetes Mellitus with Hypercholesterolemia ». Dans Lipoprotein Metabolism and Atherogenesis, 77–79. Tokyo : Springer Japan, 2000. http://dx.doi.org/10.1007/978-4-431-68424-4_18.
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Sun, Peng, et Yong-Yue Yang. « Study of inhibitory effect of ultrasound on algae and its influencing factors ». Dans Environment, Energy and Sustainable Development, 1069–72. CRC Press, 2013. http://dx.doi.org/10.1201/b16320-220.
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Moerel, Lokke. « The Impact of IR4 on Corporate Governance of Listed Companies ». Dans Global Business Leadership Development for the Fourth Industrial Revolution, 65–94. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4861-5.ch003.
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The digital revolution transforms business models and presents new privacy issues and ethical dilemmas. Research by MIT Sloan CISR reports that U.S. listed companies that have a digitally savvy board show substantially better financial performance. What is a digitally savvy board? What are the differences between the old and the new world? What are the new ethical dilemmas and how do you prevent making the same mistakes as big tech? Why does innovation fail so often within the existing structures of established companies? Why does the three lines of defense model for risk management have an inhibitory effect on innovation in practice? The author discusses these questions and provides suggestions for improvement of corporate governance of established companies. In the next chapter, the author provides rules of the road for how established companies can monetize their data including some pitfalls for established companies and discusses a number of ethical dilemmas that companies encounter in practice when implementing new digital technologies and services.
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Yan, Tingting, Benzhe Ding et Hui Wang. « Research on Carbon Emission in Liaoning Province Based on Kaya Identity ». Dans Advances in Transdisciplinary Engineering. IOS Press, 2022. http://dx.doi.org/10.3233/atde220299.
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For studying the role of energy structure change in carbon intensity in Liaoning Province, this paper uses the modified model of Kaya identity and the carbon intensity factor decomposition model of industrial and energy construction to calculate the contribution of energy structure to carbon intensity change elements and reveal the causes of carbon intensity factors in Liaoning Province. The carbon intensity factor is also affected by the total energy consumption, economic development, industrial structure, population and technological advancement. Therefore, the ridge regression model is established to further clarify the direct, indirect and total effects of the carbon intensity factor of energy construction, and the path analysis is made. According to the outcomes, the direct inhibitory role of energy structure in reducing carbon intensity is relatively small, which is mainly reflected in the indirect inhibitory effect of elements including economic development, industrial structure, technical advancement and population; The proportion of coal and primary power consumption is the main driving force for the decline of carbon intensity, while the proportion of oil and natural gas consumption and energy intensity inhibit it.
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Svard, Lois. « Does Music Really Make You Smarter ? » Dans The Musical Brain, 186—C10P107. Oxford University PressNew York, 2023. http://dx.doi.org/10.1093/oso/9780197584170.003.0010.
Texte intégralRésumé :
Abstract There is no evidence that listening to music makes one smarter, but there is considerable evidence that learning to play a musical instrument and making music gives lifelong cognitive advantages in many areas. Neural resources developed while studying music have both a near transfer effect (areas closely related to music) and a far transfer effect (areas unrelated to music). Studying music has a far transfer effect on the study of mathematics; they share spatial-temporal reasoning. Studying music also has a far transfer effect on executive function skills (inhibitory control, working memory, and cognitive flexibility) and on speech processing abilities. Musicians have heightened responses to the acoustic details of speech (pitch, timing, timbre), and because the same auditory pathway is used for both music and speech, the enhancements from studying music transfer to speech processing and language. Because studying music has a transfer effect to speech processing, community or in-school music classes can improve the neural encoding of speech for at-risk children, leading to better language development and reading, and thus to academic success.
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Jahangeer, Muhammad, Areej Riasat, Zahed Mahmood, Muhammad Numan, Naveed Munir, Mehvish Ashiq, Muhammad Asad, Usman Ali et Mahwish Salman. « Secondary Metabolites from Saccharomyces cerevisiae Species with Anticancer Potential ». Dans Saccharomyces. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.95067.
Texte intégralRésumé :
Chemotherapeutic agents produce from numerous sources such as animals, plants and micro-organisms are derived from the natural products. Although the existing therapeutic pipeline lacks fungal-derived metabolites, but hundreds of secondary metabolites derived from fungi are known to be possible chemotherapies. Over the past three decades, several secondary metabolites such as flavonoids, alkaloids, phenolic and polyketides have been developed by Saccharomyces cerevisiae species with exciting activities that considered valued for the growth of new chemotherapeutic agents. Many secondary metabolites are protective compounds which prevent abiotic and biotic stresses, i.e. predation, infection, drought and ultraviolet. Though not taking part in a living cell’s central metabolism, secondary metabolites play an important role in the function of an organism. Nevertheless, due to slow biomass build-up and inadequate synthesis by the natural host the yield of secondary metabolites is low by direct isolation. A detailed comprehension of biosynthetic pathways for development of secondary metabolites are necessary for S. cerevisiae biotransformation. These metabolites have higher inhibitory effect, specificity among cancer and normal cells, and the mechanism of non-apoptotic cell killing. This study shows the significance of bioactive compounds produced by S. cerevisiae species with their possible activity and value in chemotherapeutic drugs pipeline. The isolation and alteration of these natural secondary metabolites would promote the development of chemotherapeutic drugs.
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Aruwa, Christiana E., et Saheed Sabiu. « Oxidative Stress Involvement in Antibacterial Therapy ». Dans Therapeutic Use of Plant Secondary Metabolites, 297–322. BENTHAM SCIENCE PUBLISHERS, 2022. http://dx.doi.org/10.2174/9789815050622122010015.
Texte intégralRésumé :
Antimicrobial therapy is necessary to reduce the global burden of diseaseand infection. Oxidative stress (OS) may play a key function in determining the extentof efficacy of antimicrobial treatment regimens. However, whether the agent has a‘static’ (inhibitory) or ‘cidal’ (killing) effect or the ability to induce an oxidative state,achieving therapy is a complex one. Bactericidal agents are known to induce adownstream cascade of responses in bacteria beyond their direct target(s). Theseresponses correspond with the generation of reactive oxygen species (ROS) and thedevelopment of OS that eventually results in the disruption/destruction of integralcomponents and/or processes within bacteria cells. In contrast, bacteriostatic antibioticsmay not always induce cell death. Both classes of antimicrobials are useful inantibacterial therapy. The actualization of an oxidatively stressed microbial cell is keyto optimizing the available antibiotic therapy options for efficient treatment andreducing the acquisition of microbial resistance. Studies are still required to expatiateon the role played by OS in antimicrobial therapy. This chapter, therefore, focuses ondiscussing available research data and knowledge on this complex role by OS, whilehighlighting potential future application and development prospects. In addition, thechapter touched OS and their sources, antimicrobial lethality-OS association, factorsaffecting OS-mediating therapy and efficacy, bacterial adaptations to OS in response toantimicrobial treatment and prospects for combination therapy with bactericidal agentsand adjuvants.
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Gunathilaka, Thilina, Lakshika Rangee Keertihirathna et Dinithi Peiris. « Advanced Pharmacological Uses of Marine Algae as an Anti-Diabetic Therapy ». Dans Pharmacognosy - Medicinal Plants [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96807.
Texte intégralRésumé :
Marine seaweeds are a promising source of bioactive secondary metabolites that can be utilized in drug development and nutraceuticals. Diabetes mellitus is a leading non-communicable disease, and it is the third leading cause of death worldwide. Among the types of diabetes, type 2 became the major health problem as it is associated with severe health complications. Since available oral hypoglycemic drugs cause several adverse effects, it is worth searching for a natural cure with fewer or no side effects that may benefit patients with type 2 diabetes. Among the marine seaweeds, brown and red seaweeds are extensively studied for the anti-diabetic activity compared to the green seaweeds. Bioactive compounds present in marine seaweeds possess anti-diabetic potential through diverse mechanisms, mainly by reducing postprandial hyperglycemia and associated complication. Most of the studies emphasized that the marine seaweeds control the hyperglycemic condition by inhibiting carbohydrate hydrolyzing α-amylase,α glucosidase enzymes, and the inhibitory effect of dipeptide peptidase-4 that are involved in the degradation of incretins. Similarly, bioactive compounds in marine seaweeds can reduce diabetes complications by inhibiting angiotensin-converting enzymes, aldose reductase, protein tyrosine phosphatase 1B enzyme. This chapter focuses on the anti-diabetic potential of marine brown, green, and red seaweeds through different mechanisms.
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Ghosh, Joydip. « Therapeutic Efficacy of Natural Products Towards Protozoan Diseases ». Dans Recent Trends and The Future of Antimicrobial Agents - Part I, 174–201. BENTHAM SCIENCE PUBLISHERS, 2023. http://dx.doi.org/10.2174/9789815079609123010009.
Texte intégralRésumé :
The different infections caused by protozoan parasites, such as malaria, leishmaniasis, toxoplasmosis, balantidiasis, trichomoniasis, giardiasis, Chagas disease, amoebic dysentery, are responsible for considerable morbidity and mortality worldwide with desolating social and economic consequences. These protozoan diseases occur all over the world. For the treatment of these diseases, there is a lack of effective, safe, and affordable therapies. Due to the lack of vaccines in most instances and the development of resistant strains to the available synthetic therapeutics, it is important to search for alternative sources of anti-parasitic drugs. Since ancient times, natural products have been used as sources of potential drugs to cure diseases. It has been reported that 80% of drug molecules are natural products. The diversity of natural products can vary, i.e., it may be found in plants, fungi, algae and marine organisms. The plant-based natural products (secondary metabolites), i.e., alkaloids, phenolics, terpenes, and lipids, are potent anti-protozoal molecules. The natural products (secondary metabolites) obtained from microbial origin showed promising anti-protozoal activity. These bio-active molecules 2-(hept-1-enyl)-3-(hydroxymethyl)- 5-(3-methyl but-2-enyl)benzene-- ,4-diol, flavoglaucin, tetrahydroauroglaucin, auroglaucin, 2-(20,3-epoxy-10- 30-heptadienyl)-6-hydroxy-5-(3-methyl-2-butenyl)benzaldehyde, obtained from the fungus Eurotium repens, showed anti-malarial activities even chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum. Some of the flavonoid compounds, i.e., eupatilin, jaceosidin and nepetin, isolated from the plant Eupatorium arnottianum, showed the highest activity against Chagas disease. The three most important flavonoids, namely kaempferol, (–)-epicatechin and tiliroside showed promising activity against Entamoeba histolytica. The isoquinoline alkaloid berberine is found in several medicinal plants. Berberine salts have profound inhibitory activity against Giardia trophozoites. Two flavonoids, i.e., luteolin and quercetin, isolated from Vitex negunsdo and Fagopyrum esculentum, showed anti-leishmanial activity. An aclerodane diterpene isolated from an ethanolic extract of Polyalthia longifolia displayed anti-leishmanial activity against Leishmania donovani. A novel triterpene Astrakurkurone isolated from the wild edible mushroom, Astraeus hygrometricus, has a definitive effect on promastigote and amastigote form both in vitro and in vivo against L. donovani. Natural products have displayed promising activity against different protozoan infections, but most of these studies on natural products have been performed in vitro only. The transitions from in vitro study to in vivo trials and also the clinical trials of the new compounds are urgently required to prove their efficacy and safety.
Actes de conférences sur le sujet "Inhibitory effect on mycelial development"
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da Silva, Sergio E. Lemos, Kimberlly Soares Brito Bratifich et eloisa Teresa Corradini Santos. « Alternative and sustainable control of the fungus Sclerotinia sclerotiorum that causes white mold in soybeans ». Dans I South Florida Congress of Development. CONGRESS PROCEEDINGS I South Florida Congress of Development - 2021, 2021. http://dx.doi.org/10.47172/sfcdv2021-0005.
Texte intégralRésumé :
The Sclerotinia sclerotiorum is a phytopathogenic fungus that causes the White Mold of soybean, being responsible for losses of up to 100% in agricultural production. The objective of this work was to verify and analyze the effect of the raw aqueous extract (EBA) of ginger Zingiber officinalis on a strain of Sclerotinia Sclerotiorum isolated from soybean, cultivated and maintained in vitro in laboratory. The methodology consisted of a longitudinal study of the statistical analysis of the mycelial growth velocity index (MICV), after treatment of the mycelia with different concentrations of aqueous crude extract. The results showed a direct relationship between increasing concentration of EBA and a significant negative effect on the growth of scleroderia. It was possible to conclude that the antifungal activity of ginger EBA was able to inhibit the in vitro growth of Sclerotinia sclerotiorum, with potential protection of soybean crops; it can become a sustainable alternative in the control of this fungus, by decreasing the use of agrochemicals that cause damage to public health and environmental damage.
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M.A., Polovinkina, Osipova A.D., Osipova V.P., Kolyada M.N. et Velikorodov A.V. « PROTECTIVE EFFECT OF THE HYDROXY DERIVATIVE OF CHALCON ». Dans II INTERNATIONAL SCIENTIFIC AND PRACTICAL CONFERENCE "DEVELOPMENT AND MODERN PROBLEMS OF AQUACULTURE" ("AQUACULTURE 2022" CONFERENCE). DSTU-Print, 2022. http://dx.doi.org/10.23947/aquaculture.2022.100-102.
Texte intégralRésumé :
In this work, a study of the protective properties of a new hydroxy derivative of chalcone was carried out in comparison with a water-soluble analogue of vitamin E - trolox. The inhibitory activity of the compounds was evaluated on a model system of the long-term process of lipid peroxidation in Siberian sturgeon sperm without and with the addition of a cryo-medium. The prolonged antioxidant activity of chalcone, comparable with the action of the reference compound, was established. An increase in the time of sperm motility in the presence of the compounds under study, while maintaining a survival rate of 100%, allows us to consider the hydroxy derivative of chalcone as an potential cryoprotectant.
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Uzunova, A. « SEX DIFFERENCE IN THE INHIBITORY EFFECT OF ASPIRIN UPON THE DEVELOPMENT OF OCCLUSIVE ARTERIAL THROMBOSIS IN RATS ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643416.
Texte intégralRésumé :
The aim of the study was to investigate the effect of aspirin upon the development of occlusive arterial thrombosis in rats of either sex. For this purpose 3 months old male and female Wistar rats were pretreated with three different doses of aspirin: 10, 30 and 60 mg/kg b.w., orally by stomach tube, 3 hours before the thrombosis procedure. Occlusive arterial thrombosis was induced by the method of Hornstra and Vendel-mans-Starrenburg (1973). The dry thrombus weight (TW) and the obstruction time (OT) of the bypass-cannula served as criteria for the degree of the development of thrombosis.The results showed a dose-dependent statistically significant inhibition of arterial thrombosis in male rats by all doses of aspirin studied. TW was decreased 2, 2.5 and 9 times by 10, 30 and 60 mg/kg aspirin respectively. OT was significantly prolonged in male rats by all doses of aspirin studied. Inhibition of arterial thrombosis in female rats was achieved only by the largest dose of aspirin tested - 60 mg/kg: TW was decreased and OT was prolonged. Paradoxically, female rats treated with 10 mg/kg aspirin showed a tendency for augmentation of arterial thrombosis which contrasted to the significantly decreased TW and prolonged OT of male rats given 10 mg/kg aspirin. Female rats treated with 30 mg/kg aspirin showed only a tendency for inhibition of arterial thrombosis without any significant difference for both, TW and OT. The results were interpreted as suggestive the existance of sex differences in cyclooxygenase inhibition by aspirin and/or the prostaglandin system in rats. The data obtained were in agreement with epidemiological observation of uneffectiveness of aspirin treatment of female patients with stroke. They also showed the need for the most appropriate dose of aspirin for clinical purposes which might be effective in females too.
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Hara, T., M. Iwamoto, H. Ogawa et M. Tamikawa. « PROPHYLACTIC EFFECT OF ARGIPIDINE (MD-805) ON DEVELOPMENT OF LESIONS IN RAT PERIPHERAL ARTERIAL OCCLUSION MODEL ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644802.
Texte intégralRésumé :
Argipidine ((2R,4R)-4-methyl-1-(N2-[(RS)-3-methyl-l,2,3,4-tetrahydroquinolinesulfonyl)-L-arginyl]-2-piperidinecarboxylie acid hydrate) is a potent and specific inhibitor of thrombin(Ki=0.039μM). We tested the effect of argipidine on a new animal model of peripheral arterial occlusion (PA0).PA0 was prepared by injection of 5% lactic acid into rat femoral artery. Macroscopic changes of legs progressed asfollows; change to violet color around whole paw (3-24hr), edema (3-24hr), gangrene of fingers (after 24hr) and mummification of whole paw (after 7 days). Pathological examination demonstrated partial deletion of arterial endotherial cells and subsequent occlusive arterial thrombosis. Coagulo-parameters in circulating blood did not change 3 hours after lactic acid injection. To evaluate the effect of tested antithrombotic drugs, sum of lesion grade of five fingers is used as an index of severity of. PA0.Single subcutaneous injection of argipidine 30 minutes before lactic acid injection, inhibited significantly development of lesions of the lower limb at doses lOmg/kg and 30mg/kg in a dose-dependent manner. The number of rats which showed moderate or severe lesion on their legs at 14 days after lactic acid injection was decreased to 2/8 in argipidine treated (30mg/kg) rats from 7/8 in control rats. But argipidine injected simultaneously with lactic acid showed weak inhibitory effect (not significant) and argipidine injected three hours after lactic acid injection did not showany inhibitory activity. Slight prophylactic effect was also found by subcutaneous injection of heparin at a dose of 900U/kg, but its effect were not significant.In a separate experiment, PT and APTT were assayed after subcutaneous injection of argipidine or heparin. Heparin (900U/kg) prolonged APTT much greater than argipidine (30mg/kg), but as for prolongation of PT, argipidine was more effective than heparin.These results suggest that extrinsic coagulation system plays an important role in initiation of lesions of this model.
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Rojas-Barahona, Cristian A., Carla E. Förster Marín, Francisco Aboitiz et Jorge Gaete. « ARE THERE DIFFERENCES IN THE DEVELOPMENT OF THE EXECUTIVE FUNCTIONS OF CHILDREN WITH A TYPICAL AND ATYPICAL DEVELOPMENT STIMULATED BY A GAME ON A TABLET ? » Dans International Psychological Applications Conference and Trends. inScience Press, 2021. http://dx.doi.org/10.36315/2021inpact072.
Texte intégralRésumé :
"Introduction: Executive functions (EF) are developed early, building a fundamental basis of higher cognitive processes in adulthood (Garon et al., 2008). There are studies with children of typical development (Passolunghi et al., 2006; Welsh et al., 2010) that have demonstrated the key role of EF, such as working memory, inhibitory control, planning and attentional flexibility, in initial literacy and precalculus. What is still unclear is whether these EF can be stimulated early and if it has any effect on their development. At the same time, it is known that children with atypical development, such as ADHD, have deficiencies in the development of EF (Barkley, 1997). Early stimulation of EF in this type of population will have the same effects as in a typical development population? The objective of the study is to evaluate the effect of a stimulation program of the EF (working memory, inhibitory control, planning and attentional flexibility), by means of a tablet digital game, in the development of the EF of preschool children with and without symptoms of ADHD, of socioeconomically disadvantaged sectors. Method: Two groups, control (CG) and intervention (IG) were selected at random, both were evaluated twice (before and after). In total there were 408 participants, 212 with typical development and 196 with atypical development. The IG was exposed to a digital game of EF through a tablet during 12 sessions (in the classroom). Results: The main results show differences in favor of IG in the different EF evaluated, both for children with and without ADHD symptoms, with the exception of attentional variable for which no differences were observed. There are differences in the effect of EF among children evaluated. Discussion: These differences and their possible implications in the educational and social environment are discussed."
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Voloshin, Aleksander, Nikolay Nifantiev, Mikhail Egorov, Robert Alimbekov et Vladimir Dokichev. « Development and Implementation of Green Inhibitors of Gas Hydrate Formation in the Fields of Western Siberia ». Dans SPE Russian Petroleum Technology Conference. SPE, 2021. http://dx.doi.org/10.2118/206470-ms.
Texte intégralRésumé :
Abstract The effect of biodegradable polysaccharides – sodium (NaCMC) and ethanolammonium salts of carboxymethylcellulose, dextran and arabinogalactan on the process of gas hydrate formation was studied in order to search for new "green" inhibitors of low-concentration gas hydrate formation. The ability of polysaccharides to inhibit gas hydrate formation was studied in a quasi-equilibrium thermodynamic experiment. A mixture of hydrocarbon gases with a composition typical of the composition of petroleum gas and containing 78% methane was used as a gas-hydrate-forming model medium. It was found that in concentrations of 0.005, 0.0065 and 0.008%, dextran, NaCMC and arabinogalactan as thermodynamic inhibitors exceed methanol by 170-270 times in inhibitory properties. Dextran is superior to NaCMC and arabinogalactan in terms of inhibition efficiency, reduction of gas hydrate formation rate and induction time. Since with an increase in the concentration of polysaccharides, the pressure drop of gas hydrate formation increases and the rate of formation of gas hydrates decreases according to the mechanism of action, the studied polysaccharides can be attributed to both thermodynamic and kinetic inhibitors. It is established that the molecular weight of water-soluble polysaccharides has a significant effect on their inhibitory properties. A polysaccharide with a molecular weight of 250,000 demonstrated the highest inhibitory activity among the studied samples of NaCMC, which is 400 times more effective than methanol. NaCMC with a mass of 700 thousand did not have any effect on the formation of hydrates. Among the ethanolammonium salts, the monoethanolammonium salt CMC showed the greatest effectiveness in inhibiting the formation of tetrahydrofuran hydrates. An increase in its concentration from 0.02 to 0.1% leads to an increase in the induction time required for the nucleation and subsequent growth of crystals by 10 times. When switching from mono - to di - and triethanolammonium salts of carboxymethylcellulose, the inhibition efficiency decreases. It is shown that sodium and ethanolammonium salts of carboxymethylcellulose, arabinogalactan and dextran are promising for creating new "green" highly effective inhibitors of gas hydrate formation on their basis. The results of laboratory and field tests of the preparative form of the "green" gas hydrate formation inhibitor at the fields of Western Siberia are presented. It was found that at dosages of 500 g/m3 or less, there is no formation of hydrate plugs in the annulus of wells.
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Knoller, S., et N. Savion. « MODULATION OF ANTITHROMBIN III ACTIVITY AND ANTITHROMBIN III-THROMBIN COMPLEXES BINDING TO CULTURED CELLS BY MONOCLONAL ANTIBODIES AGAINST ANTITHROMBIN III ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644361.
Texte intégralRésumé :
Two monoclonal antibodies (mAb's) against antithrombin III (ATIII) were characterized with respect to their ability to interfere with ATIII activity. AT III activity was measured by its ability to inhibit the amidolitic activity of thrombin on the substrate BCP-100. Incubation of 150 ng of ATIII with 28pg mAb A36R2 prior to addition of 50 ng thrombin totally abolishes the inhibitory effect of ATIII on thrombin. Incubation of 200ng of ATIII with 10 μg of mAb B26R4 prior to addition of 75 ng thrombin raises the inhibitory effects of ATIII from 37% to 100%. We examined the effect of these mAb's on binding of antithrombin III-thrombin (ATIII-Th) complexes to bovine corneal endothelial cells. 120 pg/ml mAb's are reacted with 2 μg/ml ATIII-Th complexes prior to their addition to the cells. mAb A36R2 completely blocks ATIII-Th complexes binding. In contrast, mAb B26R4 enhances binding up to 250% of the control binding.We conclude that mAb A36R2 prevents binding of thrombin to ATIII by recognizing an epitope on ATIII close to thrombin binding site or that its binding to ATIII induces a conformational change in the thrombin binding site thus it no longer recognizes thrombin. mAb B26R4 has a heparin-like effect on ATIII: Its binding to ATIII induces conformational changes which improve thrombin binding to ATIII. There is a correlation between inhibition and enhancement of thrombin binding to ATIII and of ATIII-Th complexes binding to cells by the two mAb's. These mAb's may provide a new tool to control the activity of ATIII and to identify the cellular binding site on the ATIII-Th complex.This research was supported by a grant from the National Council for Research and Development, Israel and G.S.F. München, Germany.
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Zhao, Jingyun, Fuzhen Chen et Hong Yan*. « Study Of Atomization Model Of Prefilming Atomizer Considering Mass And Heat Transfer Processes ». Dans GPPS Xi'an21. GPPS, 2022. http://dx.doi.org/10.33737/gpps21-tc-84.
Texte intégralRésumé :
Liquid film propagation and breakup in the prefilming atomizer is controlled by two instabilities, one is the Kelvin- Helmholtz (KH) instability leading to the formation of longitudinal waves, and the other is the Rayleigh-Taylor (RT) instability causing the liquid film to break into droplets. At present, most of the atomization models of prefilming atomizers are established without considering the effect of the heat and mass transfer processes between the high-temperature gas and liquid film. The current study for the first time explores this effect on the change of KH and RT instabilities and film propagation and breakup processes, and implements this effect into the atomization model. Results show that the mass and heat transfer processes promote the development of KH instability and have an inhibitory effect on the development of RT instability. Furthermore, the most amplified wavelength of transverse waves caused by RT instability is used to characterize the Sauter mean diameter (SMD) and droplet size distribution of the droplets. The droplet SMD of the primary breakup decreases linearly with the increase of temperature, but the uniformity of the droplets deteriorates. This newly developed atomization model can be used to predict the size and distribution of droplets more accurately.
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Kitagawa, H., N. Yamamoto, G. Kosaki et H. Yamazaki. « AN IMPORTANT ROLE OF CARBOHYDRATE MOIETIES ON CANCER CELL MEMBRANE GLYCOPROTEINS IN CANCER CELL-INDUCED PLATELET AGGREGATION ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644667.
Texte intégralRésumé :
Platelet aggregation induced by cancer cells may be an essential process in the development of hematogenous metastasis of cancers. A mechanism in HMV-I (human vaginal melanoma cell line)-induced platelet aggregation was studied by using monoclonal antibodies against membrane proteins of cancer cells or platelets. HMV-I cells or their membrana ractions induced platelet aggregation of human heparinized PRP, to which hirudin had no inhibitory effect. The platelet aggregation by HMV-I was completely lost after the pretreatment of the cells with 0.3U/ml neuraminidase for 60 min at 37°C. Preincubation of platelets with monoclonal antibodies against platelet GP lb or GP Ilb/lIIa inhibited HMV-I induced aggregation. A monoclonal antibody MB3 (igM) against another human melanoma (HMMB) which had been transplanted in nude mice was produced by hybridoma technique. Screening studies by cell binding ELISA revealed that MB3 antibody reacted with not only HMMB cells but also many other cells including HMV-I, M7609 (colon carcinoma cell line) and normal fibroblasts. Western-blot analyses showedthat MB3 antibody reacted with multiple, more than ten, proteins with molecular weights ranging from UO to 200 kDa in unreduced SDS-PAGE of HMV-I, HMMB or M7609. In contrast, when .these cells pretreated with neuraminidase were used in Western-blot, MB3 reactivity were all lost. MB3 reacted with at least three glycoproteins of human red cell membrane in Western-blot, but it did not react with human platelets. Immune adherent asgay with trypsin-treated HMV-I or HMMB cells as target cells showed negative reactivity. MB3 antibody inhibited HMV-I-induced aggregation of platelets, but did not inhibit M7609-induced aggregation which depended on thrombin generation.These results suggest that MB3 antibody may be against sialic acid-containing carbohydrate moieties of membrane glycoproteins on these cancercells and that the carbohydrate(s) may play a critical role in' cancer cell-platelet interaction.
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Yan, Yuchao, Zhentao Liu et Jinlong Liu. « Hydrogen Enriched Ammonia Engines : Assessment of Hydrogen Concentration in the Fuel Feed from the Laminar Flame Speed Viewpoint ». Dans ASME 2022 ICE Forward Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/icef2022-88682.
Texte intégralRésumé :
Abstract The global trend toward decarbonization is inspiring researchers to search for low or even zero carbon fuels for internal combustion engines. Ammonia (NH3) is considered a potential alternative fuel to conventional gasoline and diesel without carbon emissions. Although it is not an ideal fuel for use in engines due to its poor combustion properties, the use of hydrogen (H2), which has low ignition energy and can be decomposed from ammonia, as a combustion promoter can enhance its suitability for engine applications. A careful literature review indicates that the relatively few existing studies on NH3/H2 engines and the uncertainty of the NH3/H2 chemistry under typical high-temperature and high-pressure engine environments limit the determination of the ammonia-to-hydrogen ratio. However, this question is important when converting an existing engine to ammonia operation because it is related to compression ratio determination, aftertreatment design, ECU mapping, and on-board hydrogen production rate requirements. In other words, this outstanding question would affect the simultaneous design of other accessory systems and the development of ammonia engines. To increase the knowledge of the hydrogen concentration in the fuel feed of ammonia fueled engines in the engine community, this study discusses this question from the perspective of laminar flame speed (LFS), because it is closely related to reactivity, diffusivity, and exothermicity, which is a macroscopic parameter of premixed combustion and directly affects the efficiency and emissions of spark ignition engines. Specifically, the required proportion of hydrogen blended with ammonia is determined by comparing the NH3/H2 reaction time scale with the millisecond combustion time scale in typical engines. The results show that high temperature enhances the LFS of ammonia, hydrogen and their mixtures, while pressure has an inhibitory effect. In addition, increasing the compression ratio and avoiding fuel-lean operation are effective ways to improve the performance of ammonia combustion with less hydrogen. Considering the high required hydrogen consumption rate and the full load conditions that guarantee high combustion efficiency, off-road application may be a suitable scenario for ammonia-hydrogen engines. Before applying ammonia to automobiles, the technology for on-board hydrogen production should be effectively developed.
Rapports d'organisations sur le sujet "Inhibitory effect on mycelial development"
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VanderGheynst, Jean, Michael Raviv, Jim Stapleton et Dror Minz. Effect of Combined Solarization and in Solum Compost Decomposition on Soil Health. United States Department of Agriculture, octobre 2013. http://dx.doi.org/10.32747/2013.7594388.bard.
Texte intégralRésumé :
In soil solarization, moist soil is covered with a transparent plastic film, resulting in passive solar heating which inactivates soil-borne pathogen/weed propagules. Although solarization is an effective alternative to soil fumigation and chemical pesticide application, it is not widely used due to its long duration, which coincides with the growing season of some crops, thereby causing a loss of income. The basis of this project was that solarization of amended soil would be utilized more widely if growers could adopt the practice without losing production. In this research we examined three factors expected to contribute to greater utilization of solarization: 1) investigation of techniques that increase soil temperature, thereby reducing the time required for solarization; 2) development and validation of predictive soil heating models to enable informed decisions regarding soil and solarization management that accommodate the crop production cycle, and 3) elucidation of the contributions of microbial activity and microbial community structure to soil heating during solarization. Laboratory studies and a field trial were performed to determine heat generation in soil amended with compost during solarization. Respiration was measured in amended soil samples prior to and following solarization as a function of soil depth. Additionally, phytotoxicity was estimated through measurement of germination and early growth of lettuce seedlings in greenhouse assays, and samples were subjected to 16S ribosomal RNA gene sequencing to characterize microbial communities. Amendment of soil with 10% (g/g) compost containing 16.9 mg CO2/g dry weight organic carbon resulted in soil temperatures that were 2oC to 4oC higher than soil alone. Approximately 85% of total organic carbon within the amended soil was exhausted during 22 days of solarization. There was no significant difference in residual respiration with soil depth down to 17.4 cm. Although freshly amended soil proved highly inhibitory to lettuce seed germination and seedling growth, phytotoxicity was not detected in solarized amended soil after 22 days of field solarization. The sequencing data obtained from field samples revealed similar microbial species richness and evenness in both solarized amended and non-amended soil. However, amendment led to enrichment of a community different from that of non-amended soil after solarization. Moreover, community structure varied by soil depth in solarized soil. Coupled with temperature data from soil during solarization, community data highlighted how thermal gradients in soil influence community structure and indicated microorganisms that may contribute to increased soil heating during solarization. Reliable predictive tools are necessary to characterize the solarization process and to minimize the opportunity cost incurred by farmers due to growing season abbreviation, however, current models do not accurately predict temperatures for soils with internal heat generation associated with the microbial breakdown of the soil amendment. To address the need for a more robust model, a first-order source term was developed to model the internal heat source during amended soil solarization. This source term was then incorporated into an existing “soil only” model and validated against data collected from amended soil field trials. The expanded model outperformed both the existing stable-soil model and a constant source term model, predicting daily peak temperatures to within 0.1°C during the critical first week of solarization. Overall the results suggest that amendment of soil with compost prior to solarization may be of value in agricultural soil disinfestations operations, however additional work is needed to determine the effects of soil type and organic matter source on efficacy. Furthermore, models can be developed to predict soil temperature during solarization, however, additional work is needed to couple heat transfer models with pathogen and weed inactivation models to better estimate solarization duration necessary for disinfestation.
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Lichter, Amnon, Gopi K. Podila et Maria R. Davis. Identification of Genetic Determinants that Facilitate Development of B. cinerea at Low Temperature and its Postharvest Pathogenicity. United States Department of Agriculture, mars 2011. http://dx.doi.org/10.32747/2011.7592641.bard.
Texte intégralRésumé :
Botrytis cinerea is the postharvest pathogen of many agricultural produce with table grapes, strawberries and tomatoes as major targets. The high efficiency with which B. cinerea causes disease on these produce during storage is attributed in part due to its exceptional ability to develop at very low temperature. Our major goal was to understand the genetic determinants which enable it to develop at low temperature. The specific research objectives were: 1. Identify expression pattern of genes in a coldenriched cDNA library. 2. Identify B. cinerea orthologs of cold-induced genes 3. Profile protein expression and secretion at low temperature on strawberry and grape supplemented media. 4. Test novel methods for the functional analysis of coldresponsive genes. Objective 1 was modified during the research because a microarray platform became available and it allowed us to probe the whole set of candidate genes according to the sequence of 2 strains of the fungus, BO5.10 and T4. The results of this experiment allowed us to validate some of our earlier observations which referred to genes which were the product of a SSH suppression-subtraction library. Before the microarray became available during 2008 we also analyzed the expression of 15 orthologs of cold-induced genes and some of these results were also validated by the microarray experiment. One of our goals was also to perform functional analysis of cold-induced genes. This goal was hampered for 3 years because current methodology for transformation with ‘protoplasts’ failed to deliver knockouts of bacteriordopsin-like (bR) gene which was our primary target for functional analysis. Consequently, we developed 2 alternative transformation platforms, one which involves an air-gun based technique and another which involves DNA injection into sclerotia. Both techniques show great promise and have been validated using different constructs. This contribution is likely to serve the scientific community in the near future. Using these technologies we generated gene knockout constructs of 2 genes and have tested there effect on survival of the fungus at low temperature. With reference to the bR genes our results show that it has a significant effect on mycelial growth of the B. cinerea and the mutants have retarded development at extreme conditions of ionic stress, osmotic stress and low temperature. Another gene of unknown function, HP1 is still under analysis. An ortholog of the yeast cold-induced gene, CCH1 which encodes a calcium tunnel and was shown to be cold-induced in B. cinerea was recently cloned and used to complement yeast mutants and rescue them from cold-sensitivity. One of the significant findings of the microarray study involves a T2 ribonuclease which was validated to be cold-induced by qPCR analysis. This and other genes will serve for future studies. In the frame of the study we also screened a population of 631 natural B. cinerea isolates for development at low temperature and have identified several strains with much higher and lower capacity to develop at low temperature. These strains are likely to be used in the future as candidates for further functional analysis. The major conclusions from the above research point to specific targets of cold-induced genes which are likely to play a role in cold tolerance. One of the most significant observations from the microarray study is that low temperature does not induce ‘general stress response in B. cinerea, which is in agreement to its exceptional capacity to develop at low temperature. Due to the tragic murder of the Co-PI Maria R. Davis and GopiPodila on Feb. 2010 it is impossible to deliver their contribution to the research. The information of the PI is that they failed to deliver objective 4 and none of the information which relates to objective 3 has been delivered to the PI before the murder or in a visit to U. Alabama during June, 2010. Therefore, this report is based solely on the IS data.
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Droby, Samir, Tim R. Gottwald, Richard Stange, Efraim Lewinsohn et T. Gregory McCollum. Characterization of the biochemical basis of host specificity of Penicillium digitatum and Penicillium italicum on citrus fruit. United States Department of Agriculture, mai 2008. http://dx.doi.org/10.32747/2008.7587726.bard.
Texte intégralRésumé :
l. This research demonstrates that citrus fruit volatiles play an important role in host recognition by P. digitatum and P. italicum. 2. Volatiles derived from non-host fruits and vegetables (apple, pear, tomato, pepper, strawberry and avocado) had no effect on promotion of spore germination and growth of citrus pathogens. 3. Citrus volatiles have a specific stimulatory effect solely on P. digitatum and P. italicum. Non-citrus pathogens such as P. expansum and B. cinerea not affected orinhibited by the volatile materials. The specific stimulatory effect of fruit peelvolatiles on citrus pathogens and inhibitory effect on non-pathogens indicateimport ant role of volatile compounds in the host selectivity of citrus postharvestpathogens. 4. Comparative CG-MS quantification was per formed and identification of volatileconstituents of citrus commercial oils, peel extracts and the headspace of thewounded fruits was completed. Monoterpenehydrocarbons (limonene, a-pinene,sabinene, and myrcene) were the most abundant in all volatiles regardless of thesource. 5. Our results demonstrated stimulation of germination and germ tube growth in both P. digitatum and P. italicum by limonene, myrcene, a-pinene, and b-pinene). Limonenewas show n to be the most efficient in induction of germination and growth in bothpathogens. 6. P. digitatum spores placed on the surface of lemon fruit, adjacent to a wounded oil gland, were induced to germinate and grow, thus supporting all the in vitro results and demonstrating that the phenomenon of stimulation of germination and growth occurs on the fruit. 7. We established that P. digitatum is capable of biotransformation of limonene to a terpineol. a-terpinel was proved to be involved in induction of fungal sporulation process. 8. Chemotropism (directional growth) of P. digitatum towards the volatiles released from the oil glands on fruit surface was demonstrated. 9. Citrus germplasm screening work for fruit susceptibility/resistance for P. digitatum infection showed no definitive results regarding host range and susceptibility.Although the sour orange selections appear to show higher resistance to infection and decay development. 10. We demonstrated that P. expansum, non citrus pathogen, is capable of germinating in citrus fruit surface wounds, but it strongly induced host resistance mechanisms which restrict it growth and prevented decay development. The host (citrus fruit) reacted strongly by production of ROS. On the other hand, P. digitatum seems to actively suppress host natural resistance mechanisms possibly through inhibiting the production of ROS production.
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Dahl, Geoffrey E., Sameer Mabjeesh, Thomas B. McFadden et Avi Shamay. Environmental manipulation during the dry period of ruminants : strategies to enhance subsequent lactation. United States Department of Agriculture, février 2006. http://dx.doi.org/10.32747/2006.7586544.bard.
Texte intégralRésumé :
The project resulted from earlier observations that environmental factors, especially photoperiod and temperature, had profound effects on milk yield in dairy cattle during lactation. More recently we had determined that photoperiod manipulation during the dry period altered milk yield in the next lactation, and this was associated with shifts in circulating concentrations of prolactin; specifically exposure to short days during the dry period decreases prolactin but increases milk yield. Because prolactin is also affected by temperature, with heat stress causing an increase in prolactin similar to that of long day exposure, we focused our efforts on determining prolactin signaling provides a common pathway for generation of environmental effects on mammary growth, development and subsequent function during the dry period of dairy ruminants. Over the project period we made significant progress toward testing our hypotheses that (I): In cows, there is a discrete duration of time during the dry period in which exposure to short days will result in optimal enhancement of mammary development and milk yield in the following lactation, and that this effect is mediated through demonstrable changes in mammary gland development, prolactin signaling, and mammary gene expression; and (II): Modulation of photoperiod and temperature during the dry period will affect milk yield in goats in the subsequent lactation via shifts in nutrient and endocrine partitioning, and mammary gene expression, during the dry period and into lactation. Cows exposed to short days for only the final 21 days of the dry period did not produce more milk that those on long day or natural photoperiod when dry. However, cows on short days for the entire 60 days dry did produce more milk than the other 3 groups. This indicates that there is a duration effect of short day exposure on subsequent milk yield. Results of the second study in cows indicate that mammary growth increases differentially during the dry period under long vs. short days, and that short days drive more extensive growth which is associated with altered prolactin signaling via decreases in an suppressors of cytokine signaling that represent an inhibitory pathway to mammary growth. Evidence from the studies in Israel confirms that goats respond to short days during the dry period in a similar manner to cows. In addition, heat stress effects on during the dry period can be limited by exposure to short days. Here again, shifts in prolactin signaling, along with changes in IGF-I secretion, are associated with the observed changes in mammary function in goats. These results have a number of biological and practical implications. For dairy producers, it is clear that we can recommend that cows and goats should be on reduced light exposure during the dry period, and further, cows and goats should be cooled to avoid heat stress during that time. Environmental influences on mammary growth are apparent during the dry period, and those effects have persistent impact in the subsequent lactation. Prolactin signaling is a consistent mechanism whereby extended light exposure and heat stress may depress mammary growth and development during the dry period. Thus, the prolactin signaling system offers an opportunity for further manipulation to improve production efficiency in dairy ruminants.
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Choudhary, Ruplal, Victor Rodov, Punit Kohli, Elena Poverenov, John Haddock et Moshe Shemesh. Antimicrobial functionalized nanoparticles for enhancing food safety and quality. United States Department of Agriculture, janvier 2013. http://dx.doi.org/10.32747/2013.7598156.bard.
Texte intégralRésumé :
Original objectives The general goal of the project was to utilize the bactericidal potential of curcumin- functionalizednanostructures (CFN) for reinforcement of food safety by developing active antimicrobial food-contact surfaces. In order to reach the goal, the following secondary tasks were pursued: (a) further enhancement of the CFN activity based on understanding their mode of action; (b) preparing efficient antimicrobial surfaces, investigating and optimizing their performance; (c) testing the efficacy of the antimicrobial surfaces in real food trials. Background to the topic The project dealt with reducing microbial food spoilage and safety hazards. Cross-contamination through food-contact surfaces is one of the major safety concerns, aggravated by bacterial biofilm formation. The project implemented nanotech methods to develop novel antimicrobial food-contact materials based on natural compounds. Food-grade phenylpropanoidcurcumin was chosen as the most promising active principle for this research. Major conclusions, solutions, achievements In agreement with the original plan, the following research tasks were performed. Optimization of particles structure and composition. Three types of curcumin-functionalizednanostructures were developed and tested: liposome-type polydiacetylenenanovesicles, surface- stabilized nanoparticles and methyl-β-cyclodextrin inclusion complexes (MBCD). The three types had similar minimal inhibitory concentration but different mode of action. Nanovesicles and inclusion complexes were bactericidal while the nanoparticlesbacteriostatic. The difference might be due to different paths of curcumin penetration into bacterial cell. Enhancing the antimicrobial efficacy of CFN by photosensitization. Light exposure strengthened the bactericidal efficacy of curcumin-MBCD inclusion complexes approximately three-fold and enhanced the bacterial death on curcumin-coated plastic surfaces. Investigating the mode of action of CFN. Toxicoproteomic study revealed oxidative stress in curcumin-treated cells of E. coli. In the dark, this effect was alleviated by cellular adaptive responses. Under light, the enhanced ROS burst overrode the cellular adaptive mechanisms, disrupted the iron metabolism and synthesis of Fe-S clusters, eventually leading to cell death. Developing industrially-feasible methods of binding CFN to food-contact surfaces. CFN binding methods were developed for various substrates: covalent binding (binding nanovesicles to glass, plastic and metal), sonochemical impregnation (binding nanoparticles to plastics) and electrostatic layer-by-layer coating (binding inclusion complexes to glass and plastics). Investigating the performance of CFN-coated surfaces. Flexible and rigid plastic materials and glass coated with CFN demonstrated bactericidal activity towards Gram-negative (E. coli) and Gram-positive (Bac. cereus) bacteria. In addition, CFN-impregnated plastic material inhibited bacterial attachment and biofilm development. Testing the efficacy of CFN in food preservation trials. Efficient cold pasteurization of tender coconut water inoculated with E. coli and Listeriamonocytogeneswas performed by circulation through a column filled with CFN-coated glass beads. Combination of curcumin coating with blue light prevented bacterial cross contamination of fresh-cut melons through plastic surfaces contaminated with E. coli or Bac. licheniformis. Furthermore, coating of strawberries with CFN reduced fruit spoilage during simulated transportation extending the shelf life by 2-3 days. Implications, both scientific and agricultural BARD Report - Project4680 Page 2 of 17 Antimicrobial food-contact nanomaterials based on natural active principles will preserve food quality and ensure safety. Understanding mode of antimicrobial action of curcumin will allow enhancing its dark efficacy, e.g. by targeting the microbial cellular adaptation mechanisms.
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Reisch, Bruce, Avichai Perl, Julie Kikkert, Ruth Ben-Arie et Rachel Gollop. Use of Anti-Fungal Gene Synergisms for Improved Foliar and Fruit Disease Tolerance in Transgenic Grapes. United States Department of Agriculture, août 2002. http://dx.doi.org/10.32747/2002.7575292.bard.
Texte intégralRésumé :
Original objectives . 1. Test anti-fungal gene products for activity against Uncinula necator, Aspergillus niger, Rhizopus stolonifer and Botrytis cinerea. 2. For Agrobacterium transformation, design appropriate vectors with gene combinations. 3. Use biolistic bombardment and Agrobacterium for transformation of important cultivars. 4. Characterize gene expression in transformants, as well as level of powdery mildew and Botrytis resistance in foliage of transformed plants. Background The production of new grape cultivars by conventional breeding is a complex and time-consuming process. Transferring individual traits via single genes into elite cultivars was proposed as a viable strategy, especially for vegetatively propagated crops such as grapevines. The availability of effective genetic transformation procedures, the existence of genes able to reduce pathogen stress, and improved in vitro culture methods for grapes, were combined to serve the objective of this proposal. Effective deployment of resistance genes would reduce production costs and increase crop quality, and several such genes and combinations were used in this project. Progress The efficacy of two-way combinations of Trichoderma endochitinase (CHIT42), synthetic peptide ESF12 and resveratrol upon the control of growth of Botrytis cinerea and Penicillium digitatum were evaluated in vitro. All pairwise interactions were additive but not synergistic. Per objective 2, suitable vectors with important gene combinations for Agrobacterium transformation were designed. In addition, multiple gene co-transformation by particle bombardment was also tested successfully. In New York, transformation work focused on cultivars Chardonnay and Merlot, while the technology in Israel was extended to 41B, R. 110, Prime, Italia, Gamay, Chardonnay and Velika. Transgenic plant production is summarized in the appendix. Among plants developed in Israel, endochitinase expression was assayed via the MuchT assay using material just 1-5 days after co-cultivation. Plants of cv. Sugraone carrying the gene coding for ESF12, a short anti-fungal lytic peptide under the control of the double 358 promoter, were produced. Leaf extracts of two plants showed inhibition zones that developed within 48 h indicating the inhibitory effect of the leaf extracts on the six species of bacteria. X fastidiosa, the causal organism of Pierce's disease, was very sensitive to leaf extracts from ESF12 transformed plants. Further work is needed to verify the agricultural utility of ESF12 transformants. In New York, some transformants were resistant to powdery mildew and Botrytis fruit rot. Major conclusions, solutions, achievements and implications The following scientific achievements resulted from this cooperative BARD project: 1. Development and improvement of embryogenesis and tissue culture manipulation in grape, while extending these procedures to several agriculturally important cultivars both in Israel and USA. 2. Development and improvement of novel transformation procedures while developing transformation techniques for grape and other recalcitrant species. 3. Production of transgenic grapevines, characterization of transformed vines while studying the expression patterns of a marker gene under the control of different promoter as the 35S CaMV in different part of the plants including flowers and fruits. 4. Expression of anti-fungal genes in grape: establishment of transgenic plants and evaluation of gene expression. Development of techniques to insert multiple genes. 5. Isolation of novel grape specific promoter to control the expression of future antimicrobial genes. It is of great importance to report that significant progress was made in not only the development of transgenic grapevines, but also in the evaluation of their potential for increased resistance to disease as compared with the non engineered cultivar. In several cases, increased disease resistance was observed. More research and development is still needed before a product can be commercialized, yet our project lays a framework for further investigations.
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Dolja, Valerian V., Amit Gal-On et Victor Gaba. Suppression of Potyvirus Infection by a Closterovirus Protein. United States Department of Agriculture, mars 2002. http://dx.doi.org/10.32747/2002.7580682.bard.
Texte intégralRésumé :
The plant virus family Polyviridae is the largest and most destructive of all plant viruses. Despite the continuous effort to develop resistant plant varieties, there is a desperate need for novel approaches conferring wide-range potyvirus resistance. Based on experiments with the tobacco etch potyvirus (TEV)-derived gene expression vector, we suggested approach for screening of the candidate resistance genes. This approach relies on insertion of the genes into a virus vector and evaluation of the phenotypes of the resulting recombinant viruses. The genes which suppress infection by the recombinant virus are selected as candidates for engineering transgenic resistance. Our analysis of the TEV variants expressing proteins of the beet yellows closterovirus (BYV) revealed that one of those, the leader proteinase (L-Pro), strongly and specifically interfered with the hybrid TEV infection. Since closterovirus L-Pro is evolutionary related to potyviral helper component-proteinase (HC-Pro), we suggested that the L-Pro interfered with HC-Pro function via a trans-dominant inhibitory effect. Based on these findings, we proposed to test two major hypotheses. First, we suggested that L-Pro-mediated suppression of potyvirus infection is a general phenomenon effective against a range of potyviruses. The second hypothesis stated that the suppression effect can be reproduced in transgenic plants expressing L-Pro, and can be utilized for generation of resistance to potyviruses. In accord with these hypotheses, we developed two original objectives of our proposal: A) to determine the range of the closterovirus-derived suppression of potyviral infection, and B) to try and utilize the L-Pro-mediated suppression for the development of transgenic resistance to potyviruses. In the first phase of the project, we have developed all major tools and technologies required for successful completion of the proposed research. These included TEV and ZYMV vectors engineered to express several closteroviral L-Pro variants, and generation of the large collection of transgenic plants. To our satisfaction, characterization of the infection phenotypes exhibited by chimeric TEV and ZYMV variants confirmed our first hypothesis. For instance, similar to TEV-L- Pro(BYV) chimera, ZYMV-L-Pro(LIYV) chimera was debilitated in its systemic spread. In contrast, ZYMV-GUS chimera (positive control) was competent in establishing vigorous systemic infection. These and other results with chimeric viruses indicated that several closteroviral proteinases inhibit long-distance movement of the potyviruses upon co-expression in infected plants. In order to complete the second objective, we have generated ~90 tobacco lines transformed with closteroviral L-Pro variants, as well as ~100 lines transformed with BYV Hsp70-homolog (Hsp70h; a negative control). The presence and expression of the trans gene in each line was initially confirmed using RT-PCR and RNA preparations isolated from plants. However, since detection of the trans gene-specific RNA can not guarantee production of the corresponding protein, we have also generated L-Pro- and Hsp70h-specific antisera using corresponding synthetic peptides. These antisera allowed us to confirm that the transgenic plant lines produced detectable, although highly variable levels of the closterovirus antigens. In a final phase of the project, we tested susceptibility of the transgenic lines to TEV infection. To this end, we determined that the minimal dilution of the TEV inoculum that is still capable of infecting 100% of nontransgenic plants was 1:20, and used 10 plants per line (in total, ~2,000 plants). Unfortunately, none of the lines exhibited statistically significant reduction in susceptibility. Although discouraging, this outcome prompted us to expand our experimental plan and conduct additional experiments. Our aim was to test if closteroviral proteinases are capable of functioning in trans. We have developed agroinfection protocol for BYV, and tested if co- expression of the L-Pro is capable of rescuing corresponding null-mutant. The clear-cut, negative results of these experiments demonstrated that L-Pro acts only in cis, thus explaining the lack of resistance in our transgenic plants. We have also characterized a collection of the L-Pro alanine- scanning mutants and found direct genetic evidence of the requirement for L-Pro in virus systemic spread. To conclude, our research supported by BARD confirmed one but not another of our original hypotheses. Moreover, it provided an important insight into functional specialization of the viral proteinases and generated set of tools and data with which we will be able to address the molecular mechanisms by which these proteins provide a variety of critical functions during virus life cycle.
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Meidan, Rina, et Robert Milvae. Regulation of Bovine Corpus Luteum Function. United States Department of Agriculture, mars 1995. http://dx.doi.org/10.32747/1995.7604935.bard.
Texte intégralRésumé :
The main goal of this research plan was to elucidate regulatory mechanisms controlling the development, function of the bovine corpus luteum (CL). The CL contains two different sterodigenic cell types and therefore it was necessary to obtain pure cell population. A system was developed in which granulosa and theca interna cells, isolated from a preovulatory follicle, acquired characteristics typical of large (LL) and small (SL) luteal cells, respectively, as judged by several biochemical and morphological criteria. Experiments were conducted to determine the effects of granulosa cells removal on subsequent CL function, the results obtained support the concept that granulosa cells make a substaintial contribution to the output of progesterone by the cyclic CL but may have a limited role in determining the functional lifespan of the CL. This experimental model was also used to better understand the contribution of follicular granulosa cells to subsequent luteal SCC mRNA expression. The mitochondrial cytochrome side-chain cleavage enzyme (SCC), which converts cholesterol to pregnenolone, is the first and rate-limiting enzyme of the steroidogenic pathway. Experiments were conducted to characterize the gene expression of P450scc in bovine CL. Levels of P450scc mRNA were higher during mid-luteal phase than in either the early or late luteal phases. PGF 2a injection decreased luteal P450scc mRNA in a time-dependent manner; levels were significantly reduced by 2h after treatment. CLs obtained from heifers on day 8 of the estrous cycle which had granulosa cells removed had a 45% reduction in the levels of mRNA for SCC enzymes as well as a 78% reduction in the numbers of LL cells. To characterize SCC expression in each steroidogenic cell type we utilized pure cell populations. Upon luteinization, LL expressed 2-3 fold higher amounts of both SCC enzymes mRNAs than SL. Moreover, eight days after stimulant removal, LL retained their P4 production capacity, expressed P450scc mRNA and contained this protein. In our attempts to establish the in vitro luteinization model, we had to select the prevulatory and pre-gonadotropin surge follicles. The ratio of estradiol:P4 which is often used was unreliable since P4 levels are high in atretic follicles and also in preovulatory post-gonadotropin follicles. We have therefore examined whether oxytocin (OT) levels in follicular fluids could enhance our ability to correctly and easily define follicular status. Based on E2 and OT concentrations in follicular fluids we could more accurately identify follicles that are preovulatory and post gonadotropin surge. Next we studied OT biosynthesis in granulosa cells, cells which were incubated with forskolin contained stores of the precursor indicating that forskolin (which mimics gonadotropin action) is an effective stimulator of OT biosynthesis and release. While studying in vitro luteinization, we noticed that IGF-I induced effects were not identical to those induced by insulin despite the fact that megadoses of insulin were used. This was the first indication that the cells may secrete IGF binding protein(s) which regonize IGFs and not insulin. In a detailed study involving several techniques, we characterized the species of IGF binding proteins secreted by luteal cells. The effects of exogenous polyunsaturated fatty acids and arachidonic acid on the production of P4 and prostanoids by dispersed bovine luteal cells was examined. The addition of eicosapentaenoic acid and arachidonic acid resulted in a dose-dependent reduction in basal and LH-stimulated biosynthesis of P4 and PGI2 and an increase in production of PGF 2a and 5-HETE production. Indomethacin, an inhibitor of arachidonic acid metabolism via the production of 5-HETE was unaffected. Results of these experiments suggest that the inhibitory effect of arachidonic acid on the biosynthesis of luteal P4 is due to either a direct action of arachidonic acid, or its conversion to 5-HETE via the lipoxgenase pathway of metabolism. The detailed and important information gained by the two labs elucidated the mode of action of factors crucially important to the function of the bovine CL. The data indicate that follicular granulosa cells make a major contribution to numbers of large luteal cells, OT and basal P4 production, as well as the content of cytochrome P450 scc. Granulosa-derived large luteal cells have distinct features: when luteinized, the cell no longer possesses LH receptors, its cAMP response is diminished yet P4 synthesis is sustained. This may imply that maintenance of P4 (even in the absence of a Luteotropic signal) during critical periods such as pregnancy recognition, is dependent on the proper luteinization and function of the large luteal cell.
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Altstein, Miriam, et Ronald J. Nachman. Rational Design of Insect Control Agent Prototypes Based on Pyrokinin/PBAN Neuropeptide Antagonists. United States Department of Agriculture, août 2013. http://dx.doi.org/10.32747/2013.7593398.bard.
Texte intégralRésumé :
The general objective of this study was to develop rationally designed mimetic antagonists (and agonists) of the PK/PBAN Np class with enhanced bio-stability and bioavailability as prototypes for effective and environmentally friendly pest insect management agents. The PK/PBAN family is a multifunctional group of Nps that mediates key functions in insects (sex pheromone biosynthesis, cuticular melanization, myotropic activity, diapause and pupal development) and is, therefore, of high scientific and applied interest. The objectives of the current study were: (i) to identify an antagonist biophores (ii) to develop an arsenal of amphiphilic topically active PK/PBAN antagonists with an array of different time-release profiles based on the previously developed prototype analog; (iii) to develop rationally designed non-peptide SMLs based on the antagonist biophore determined in (i) and evaluate them in cloned receptor microplate binding assays and by pheromonotropic, melanotropic and pupariation in vivo assays. (iv) to clone PK/PBAN receptors (PK/PBAN-Rs) for further understanding of receptor-ligand interactions; (v) to develop microplate binding assays for screening the above SMLs. In the course of the granting period A series of amphiphilic PK/PBAN analogs based on a linear lead antagonist from the previous BARD grant was synthesized that incorporated a diverse array of hydrophobic groups (HR-Suc-A[dF]PRLa). Others were synthesized via the attachment of polyethylene glycol (PEG) polymers. A hydrophobic, biostablePK/PBAN/DH analog DH-2Abf-K prevented the onset of the protective state of diapause in H. zea pupae [EC50=7 pmol/larva] following injection into the preceding larval stage. It effectively induces the crop pest to commit a form of ‘ecological suicide’. Evaluation of a set of amphiphilic PK analogs with a diverse array of hydrophobic groups of the formula HR-Suc-FTPRLa led to the identification of analog T-63 (HR=Decyl) that increased the extent of diapause termination by a factor of 70% when applied topically to newly emerged pupae. Another biostablePK analog PK-Oic-1 featured anti-feedant and aphicidal properties that matched the potency of some commercial aphicides. Native PK showed no significant activity. The aphicidal effects were blocked by a new PEGylated PK antagonist analog PK-dF-PEG4, suggesting that the activity is mediated by a PK/PBAN receptor and therefore indicative of a novel and selective mode-of-action. Using a novel transPro mimetic motif (dihydroimidazole; ‘Jones’) developed in previous BARD-sponsored work, the first antagonist for the diapause hormone (DH), DH-Jo, was developed and shown to block over 50% of H. zea pupal diapause termination activity of native DH. This novel antagonist development strategy may be applicable to other invertebrate and vertebrate hormones that feature a transPro in the active core. The research identifies a critical component of the antagonist biophore for this PK/PBAN receptor subtype, i.e. a trans-oriented Pro. Additional work led to the molecular cloning and functional characterization of the DH receptor from H. zea, allowing for the discovery of three other DH antagonist analogs: Drosophila ETH, a β-AA analog, and a dF analog. The receptor experiments identified an agonist (DH-2Abf-dA) with a maximal response greater than native DH. ‘Deconvolution’ of a rationally-designed nonpeptide heterocyclic combinatorial library with a cyclic bis-guanidino (BG) scaffold led to discovery of several members that elicited activity in a pupariation acceleration assay, and one that also showed activity in an H. zea diapause termination assay, eliciting a maximal response of 90%. Molecular cloning and functional characterization of a CAP2b antidiuretic receptor from the kissing bug (R. prolixus) as well as the first CAP2b and PK receptors from a tick was also achieved. Notably, the PK/PBAN-like receptor from the cattle fever tick is unique among known PK/PBAN and CAP2b receptors in that it can interact with both ligand types, providing further evidence for an evolutionary relationship between these two NP families. In the course of the granting period we also managed to clone the PK/PBAN-R of H. peltigera, to express it and the S. littoralis-R Sf-9 cells and to evaluate their interaction with a variety of PK/PBAN ligands. In addition, three functional microplate assays in a HTS format have been developed: a cell-membrane competitive ligand binding assay; a Ca flux assay and a whole cell cAMP ELISA. The Ca flux assay has been used for receptor characterization due to its extremely high sensitivity. Computer homology studies were carried out to predict both receptor’s SAR and based on this analysis 8 mutants have been generated. The bioavailability of small linear antagonistic peptides has been evaluated and was found to be highly effective as sex pheromone biosynthesis inhibitors. The activity of 11 new amphiphilic analogs has also been evaluated. Unfortunately, due to a problem with the Heliothis moth colony we were unable to select those with pheromonotropic antagonistic activity and further check their bioavailability. Six peptides exhibited some melanotropic antagonistic activity but due to the low inhibitory effect the peptides were not further tested for bioavailability in S. littoralis larvae. Despite the fact that no new antagonistic peptides were discovered in the course of this granting period the results contribute to a better understanding of the interaction of the PK/PBAN family of Nps with their receptors, provided several HT assays for screening of libraries of various origin for presence of PK/PBAN-Ragonists and antagonists and provided important practical information for the further design of new, peptide-based insecticide prototypes aimed at the disruption of key neuroendocrine physiological functions in pest insects.