Tesi sul tema "Mycology"
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1
Olsson, Johan. "Modern methods in cereal grain mycology /". Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2000. http://epsilon.slu.se/avh/2000/91-576-5792-0.pdf.
Testo completo
2
Donnison, Louise. "Mycology of haymeadows under management change". Thesis, Aberystwyth University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287116.
Testo completoAbstract (sommario):
Management improvements have caused a decline in plant species diversity in traditionally managed haymeadows. The aim of this study was examine the effects and causes of management improvements on the soil microbialocmmunity with particular emphasis on the fungal component. A seasonal study of 3 sites showed that management improvements to haymeadows consistently reduced soil microbial biomass C, but had no effect on dehydrogenase activity and basal respiration. Management improvements to these sites also caused a significant reduction in VAM spore numbers, soil fungal biomass, measured as soil ergosterol content and the PLFA 18:w6, and a decrease in the fungal:bacteria PLFA ratio. VAM spore numbers were not correlated with the possibly mycorrhizal NLFA 16:w5. In the Welsh haymeadow, fungi of the genera Fusarium, Mucor, Absidia, Cladosporium, Trichodenna, Acremonium, Zygorhynchus and Paecilomyces were commonly isolated on litter and soil. Commonly isolated fungi had proteolytic and urease activity, and approximately half had cellulose and lignin decay abilities. Management improvements induced shifts in the isolation frequency of these fungi, resulting in an increase in more general resource fungi, capable of growth on both litter and soil. Management improvements to haymeadows, may also have reduced species diversity of litter fungi. Agar and microcosm experiments established that changes in fungal community structure observed in the field could be in response to changes in plant litter inputs and applications of NPK fertiliser. Pairings of fungi on PDA showed that there was a combative hierarchy amongst the fungi, but was not able to show if this hierarchy was affected by NPK. A field experiment found no response of the soil microbial community to short term applications (2 years) of fertiliser or fungicide. The findings of this study suggest that management improvements to grasslands will induce changes in microbial and fungal community structure, this will be discussed.
3
Smith, David. "The evaluation and development of techniques for the preservation of living filamentous fungi". Thesis, Imperial College London, 1986. http://hdl.handle.net/10044/1/38164.
Testo completo
4
Dyer, Paul Stanley. "Perithecial development in Nectria haematococca mating population VI". Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386915.
Testo completo
5
Marathe, Sudhir Vasant. "Targeted mutagenesis, structure and function of a new gene required for acetate utilisation in Neurospora crassa". Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315923.
Testo completo
6
Wadekar, Rekha Vishwas. "Regulation of proteinase activities in basidiomycete wood decay fungi". Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260749.
Testo completo
7
Furlaneto, Marcia Cristina. "Genetical studies on invertase in Aspergillus nidulans". Thesis, University of Nottingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335855.
Testo completo
8
Belfield, Graham Paul. "The role of elongation factor 3 in yeast protein synthesis". Thesis, University of Kent, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358842.
Testo completo
9
Rozycka, Magdalena. "Use of biochemical and immunological methods to distinguish arbuscular mycorrhizal fungi (AMF)". Thesis, University of Kent, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387019.
Testo completo
10
Galbraith, Daniel Norman. "Molecular and immunological analysis and detection of the forest pathogen Heterbasidion annosum". Thesis, University of Abertay Dundee, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359300.
Testo completo
11
Hamer, Alison. "Dynamics of fungal growth in stored grain". Thesis, Cranfield University, 1993. http://dspace.lib.cranfield.ac.uk/handle/1826/11025.
Testo completoAbstract (sommario):
Large and small-scale respirometry apparatus were developed and optimised to measure the respiration of 25 g and 10 kg seed samples stored under a range of environmental conditions, from 0.80 to 0.95 water activity (~) and 15 to 35°C in all combinations. Respiration of wheat and barley grains was greater, than that of rapeseed and linseed. Oxygen consumption was linear with time for naturally contaminated wheat grain over the range 0.90-0.95 aw/15- 25°C and 0.80-0.95 ~/30-35°C, in sterile wheat grain at 0.90 ~125°C, and in barley and rapeseed at 0.90 ~120°C but was non-linear in wheat grain at 0.80-0.85 ~/15-25°C, linseed at 0.88 ~120°C and in autoclaved, reinoculated wheat grain. Respiration of naturally contaminated wheat grain was determined over the whole range of environmental conditions. Oxygen consumption increased with water activity and temperature. Respiration was comparable whether measured from 25 g or 10 kg samples, allowing the data to be suitable for mathematical modelling. Respiratory quotients (RQ) were generally < 1.0 and closest to 1.0 at 0.95 aw120-35°C but at 15°C they exceeded 1.0 and were closest to 1.0 at 0.80 aw • Respirometry was more sensitive than direct weighing for determining dry matter loss (DML) because fungal biomass was not measured. DML values associated with visible moulding, as calculated by oxygen consumption by wheat and barley, were smaller than those considered acceptable for safe storage. During 7 days storage at 0.85 ~125°C and 0.90 aw/15°C, conditions usually regarded as safe for short term storage, visible moulding and germination loss occurred with, respectively, as little as 0.130% and 0.085% DML. A dose of 10 kGy gamma-radiation destroyed all fungal contamination from wheat grain without affecting percentage germination, although seed vigour and respiration were decreased. Using a new dry spore inoculation method, it was shown that Eurotium amstelodami caused more DML in autoclaved than Penicillium aurantiogriseum over 28 days at 0.85-0.90 ~120°C.
12
Wynn, James Patrick. "The intermediary metabolism of Fusarium moniliforme". Thesis, University of Hull, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262424.
Testo completo
13
Gaskell, Tracey Anne. "Development and stromal structure in Daldinia concentrica (Bolt.:Fr.) (Ces. & De Not.)". Thesis, Liverpool John Moores University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262110.
Testo completo
14
Johnstone, Iain Lindsay. "Transformation of Aspergillus nidulans". Thesis, University of Glasgow, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313341.
Testo completo
15
Russell, Ian Douglas. "NOP3, a protein involved in pre-ribosomal RNA processing". Thesis, Open University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239708.
Testo completo
16
Прімова, Людмила Олександрівна, Людмила Александровна Примова, Liudmyla Oleksandrivna Primova, Юлія Сергіївна Моторна, Юлия Сергеевна Моторная e Yuliia Serhiivna Motorna. "Азотистий склад біомаси мукорового гриба Blakeslea trispora". Thesis, Видавництво СумДУ, 2008. http://essuir.sumdu.edu.ua/handle/123456789/5997.
Testo completo
17
Evans, Neal. "A study of the interactions between Alternaria linicola and linseed". Thesis, University of Glasgow, 1996. http://theses.gla.ac.uk/39033/.
Testo completoAbstract (sommario):
The principal aim of the study was to further the knowledge of the interaction between Alternaria linicola and the host plant linseed (Linum usitatissimum). A novel detached cotyledon in vitro bioassay was developed to allow the quantification of disease resistance of Linum material to A. linicola. Differences were apparent between the disease response scores of four linseed varieties when tested with seven isolates of the pathogen which differed in aggressiveness. However, there was no significant difference between the disease response scores of the varieties and no change in the ranking of varieties over three experiments. This indicated that the varieties behaved in a predictable manner to each isolate during each test. Accordingly, in a subsequent study, 102 Linum accessions were challenged with an aggressive and a non-aggressive isolate. About 75 % of the accessions gave a moderate response, although there was a continuous distribution of resistance from high susceptibility to resistant. Accessions at both extremes of the disease response consisted of breeding material, currently grown varieties and near relatives of the host species. For example, one of the more resistant accessions tested was Linum angustifolium. A sub-set of nine Linum accessions was chosen (a range of susceptible, moderately-resistant and resistant material) and the resistance response of the material to an aggressive and a non-aggressive A. linicola isolate was investigated using a whole seedling inoculation technique. A comparison of the response of the material during the seedling test with that of the detached in vitro assay indicated that the latter test systematically, but marginally, overestimated the disease response. The in vitro bioassay scores and the seedling test scores were positively correlated following inoculation with the more aggressive of the two isolates. It was suggested that the resistance response of material could be accurately predicted by the in vitro bioassay but that a certain level of isolate aggressiveness was necessary to differentiate between responses of the accessions. Since large isolate-line interactions with respect to resistance scores were not observed, the results implied that resistance was polygenically determined. These results indicate that the bioassay for disease resistance produces an accurate measure of resistance and provides plant breeders with a useful tool which can be utilised during breeding programs.
18
García, Daiana. "Predictive mycology and use of natural antifungals to prevent the mycotoxin food hazard". Doctoral thesis, Universitat de Lleida, 2012. http://hdl.handle.net/10803/93074.
Testo completoAbstract (sommario):
Filamentous moulds may cause spoilage in raw materials, foods and feeds. Some of them synthesize mycotoxins which are a risk for human and animal health. For this reason, from the food safety point of view, only mycotoxins, as chemical hazards, are important. Nevertheless, despite the absence of direct correlation between mould growth and mycotoxins production, the prevention of fungal growth in raw materials and foods leads invariably to the prevention of mycotoxins presence.
Due to the fact that moulds can contaminate foods from raw materials till end products, different strategies could be used at the different steps in the food chain. Preharvest strategies include the use of resistant varieties, crop rotation, soil preparation, optimal irrigation, fertilizer, herbicides, insecticides and chemical and biological agents application. Post-harvest strategies include improved drying and storage conditions, together with the use of natural and chemical agents. Predictive models may be used as a strategy to predict and prevent mycotoxigenjc fungal growth and mycotoxins accumulation.
The present PhD work focused in two main strategies:
a) The use of antifungals of natural origin to prevent from mycotoxigenic fungi and mycotoxins
Equisetum arvense and Stevia rebaudiana extracts were analized as possible natural agents to inhibit growth and mycotoxin accumulation in in vitro and in vivo experiments. Both extracts were effective against mycotoxigenic moulds and the mycotoxigenic Aspergillus and Fusarium isolates studied were completely inhibited by a 3% of E. arvense. However, the effect decreased in the in vivo test. In the last case, Equisetum was effective against Aspergillus section Flavi and Fusarium section Liseola growth at high water activity levels and with high infection levels, but mycotoxins levels were not significantly affected.
b) The assessment of the usefulness of predictive models to manage the mycotoxin problem
In an initial experiment, four particular points which deserved in depth study to assess the viability of predictive microbiology in the moulds field were identified: 1) models should be developed for longer time periods; 2) food and raw materials prone to mycotoxin contamination are usually stored under marginal conditions for mould growth, thus performance of models should be checked under such conditions; 3) the impact of the inoculum size in the performance of the models; and 4) the impact of the potential intraspecies variability among isolates in prediction performance.
Prediction of time to growth by kinetic models was clearly linked to inoculum size. On the other hand, the performance of predictive models may be compromised under marginal conditions for fungal growth, the higher variability of results under these conditions results in the need for a higher number of replicates required, specifically for kinetic models. For last, a high intraspecific variability on growth and mycotoxin levels has proven to be wider for the both isolates studies: A. carbonarius and P. expansum. For this reason, a greater number of strains should be included to develop models under non optimal condition for both, growth and for mycotoxin production. A matrix was built from which the number of strains and replicates to be planned for new experiments can be assessed for a reliable estimation of growth parameters and we conclude that increasing the number of strains in an experiment increases the explained variability much more than including further replicates.
Finally, a first attempt was done to model aflatoxins production as a function of growth parameters and time. Aflatoxins accumulation was shown to be better correlated to colony area than either colony diameter or fungal biomass. Luedeking-Piret model was used for this purpose, and reasonable percentages of variability were explained.
To conclude, probability models applied either to mould growth or mycotoxin production might be a valuable tool in food safety management through the food chain.
19
Boddy, Lynn M. "Regulation and molecular cloning of an invertase gene from Aspergillus niger". Thesis, University of Nottingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336021.
Testo completo
20
Schofield, David Alexander. "Regulation of chitin synthesis in Candida albicans". Thesis, University of Aberdeen, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259699.
Testo completoAbstract (sommario):
The study of the regulation of chitin synthesis in the pathogen Candida albicans is a challenging field. It not only offers a possibility of a better understanding of the dimorphic transition but also may help in the development of an effective antifungal. The suggestion that the regulation of cell wall synthesis may be closely coupled to the turgor pressure of the fungus has been investigated. The synthesis of chitin by the enzyme chitin synthase was studied under conditions of osmotic stress. Mixed membrane fractions from protoplasts of C.albicans incubated in medium of low osmolality exhibited up to four-fold greater native enzyme activity as compared to protoplasts incubated at high osmolality. This was also the case for preparations from whole cells of C.albicans, Coprinus cinereus and Saccharomyces cerevisiae and also from protoplasts from S.cerevisiae. Trypsin-treated enzyme preparations did not show this regulation to the same degree. The addition of nikkomycin Z, a differential chitin synthase inhibitor, partially restored this regulation. The synthesis of chitin, assessed by following the incorporation of (14C)-GlcNAc into chitin in the cell wall, was also greater in C.albicans cells incubated in medium of low osmolality. However, the incorporation of (14C)-GlcNAc into the cell wall of regenerating protoplasts exhibited the opposite effect. This was substantiated further by measuring the fluorescence of regenerating protoplasts following the addition of Calcofluor white. Following the attempted cloning of the C.albicans CHS3 (CSD2) gene, a detailed northern analysis of three chitin synthase genes during growth and dimorphism of C.albicans was performed. CHS1 was expressed during both the yeast and hyphal phases of growth while CHS2 and CHS3 were preferentially expressed in the hyphal form. There was no difference in expression of the chitin synthase genes in invasive and non-invasive clinical isolates of C.albicans and all three genes showed highest levels of mRNA when grown in medium of neutral pH.
21
Abarca, Salat Ma Lourdes. "Contribución al estudio de la micoflora presente en el hábitat de animales aparentemente sanos". Doctoral thesis, Universitat de Barcelona, 1986. http://hdl.handle.net/10803/672797.
Testo completoAbstract (sommario):
La célula animal puede ser parasitada por un amplio grupo de hongos miceliares y levaduras que desencadenan procesos clínicos característicos: dermatofitosis, micosis profundas, etc. Estos microorganismos han sido objeto de estudio por parte de numerosos investigadores, pero son escasos los trabajos que hacen referencia a la micoflora presente en animales sin afección fúngica alguna.
La presencia de todo tipo de hongos en la piel y plumas de los animales está directamente relacionada con el contenido en propágulos fúngicos viables del hábitat propio de cada animal: atmósfera, suelos, nidos, camas, etc.
Otro aspecto de gran interés es el de las micotoxicosis, originadas tras el consumo de alimentos contaminados por cepas fúngicas toxigéni ca s , capaces de elaborar y acumular micotoxinas sobre este sustrato o directamente por las micotoxinas, metabolitos secundarios de marcada resistencia a los factores ambientales y que una vez vertidos al medio por parte de las cepas productoras, pueden persistir activos durante un largo período de tiempo.
Por todo lo expuesto, hemos considerado de interés llevar a cabo una investigación que permita establecer la distribución de hongos en animales procedentes de granjas y explotaciones
ubicadas en su totalidad en Cataluña y que no presentaban procesos micóticos aparentes, así como estudiar la capacidad de elaborar y acumular aflatoxinas por parte de las cepas pertenecientes al grupo “Aspergillus flavus” aisladas de muestras de alimentos destinados al consumo animal, estudiando de forma exhaustiva su capacidad tóxica y determinando los niveles de las mismas que las cepas mencionadas pueden producir en diversas condiciones de cultivo.
El estudio detallado de los resultados obtenidos tiene por objeto indicar las relaciones ecológicas entre los hongos aislados de los diversos sustratos estudiados y la posible incidencia de animales portadores de hongos patógenos que pueden ser el elemento transmisor de procesos de infección a otros animales e incluso al hombre, así como detectar la presencia de cepas con capacidad de elaborar aflatoxinas, metabolitos que pueden ser acumulados en el animal y tras el consumo del mismo o de sus derivados, originar un proceso de micotoxicosis en el hombre.
22
Firacative, Ropero Sandra Carolina. "Characterization of the human pathogenic species Cryptococcus neoformans and Cryptococcus gattii with a special emphasis on emerging molecular types within C. gattii". Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/12738.
Testo completoAbstract (sommario):
The rising incidence of cryptococcosis, a life-threatening fungal infection affecting both immunocompromised and immunocompetent humans and animals, along with the emergence of outbreaks of infection, highlight the need of an increased and constant vigilance of its etiological agents Cryptococcus neoformans and C. gattii. The initial part of this PhD thesis evaluates MALDI-TOF MS and hyperbranched rolling circle PCR as two new alternative methodologies for the rapid and accurate identification of these two species and their major molecular types. The second part shows the utility of the insects Drosophila melanogaster and Galleria mellonella as invertebrate models of infection to study cryptococcal pathogenesis and virulence factors and to screen for strains with different levels of virulence. In the last part, different molecular approaches are applied to understand the epidemiology of cryptococcosis, and the differences regarding the genetic diversity, virulence and antifungal susceptibility between and within major molecular types/species. Being part of an ongoing research collaboration among different institutions, that continuously study the epidemiology, genetics and pathogenesis of these medically important yeasts, the population studies conducted during this PhD strongly contribute to our knowledge about the regional and global spread of Cryptococcus and the epidemiology of cryptococcosis.
23
Bowen, Suzanne. "Stress and stationary phase characteristics in cell wall defective strains of Saccharomyces cerevisiae". Thesis, University of Bath, 2000. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341199.
Testo completo
24
Aldars, García Laila. "Predictive mycology as a tool for controlling and preventing the aflatoxin risk in postharvest". Doctoral thesis, Universitat de Lleida, 2017. http://hdl.handle.net/10803/418806.
Testo completoAbstract (sommario):
Les aflatoxines són potents carcinògens que representen una amenaça significativa per a la salut humana. La incidència d'aquestes micotoxines en els aliments és alta, de manera que el seu control i prevenció són necessaris en la indústria alimentària. El desenvolupament de models predictius apropiats que ens permetin predir el creixement fúngic i la producció de micotoxines és de gran utilitat com a eina per controlar, predir i prevenir el risc de micotoxines en aliments. És important que els models predictius siguin capaços d'explicar les condicions ambientals que es troben al llarg de la cadena alimentària. Entre aquestes condicions trobem: condicions subòptimes per al creixement i producció de micotoxines, distribució aleatòria d'espores en l'aliment, presència de diferents soques de la mateixa espècie o condicions ambientals canviants.
El present treball proporciona una base per al desenvolupament de models científicament provats, que poden ser aplicats per la indústria alimentària per millorar el control en postcollita.Las aflatoxinas son potentes carcinógenos que representan una amenaza significativa para la salud humana. La incidencia de estas micotoxinas en los alimentos es alta, por lo que su control y prevención es obligatoria en la industria alimentaria. El desarrollo de modelos predictivos apropiados que nos permitan predecir el crecimiento fúngico y la producción de micotoxinas es de gran utilidad como herramienta para controlar, predecir y prevenir el riesgo de micotoxinas en alimentos. Es importante que los modelos predictivos sean capaces de explicar las condiciones ambientales que se encuentran a lo largo de la cadena alimentaria. Entre tales condiciones encontramos: condiciones subóptimas para el crecimiento y producción de micotoxinas, distribución aleatoria de esporas fúngicas en el alimento, presencia de diferentes cepas de la misma especie o condiciones ambientales dinámicas. El presente trabajo proporciona una base para el desarrollo de modelos científicamente probados, que pueden ser aplicados por la industria alimentaria para mejorar el control de micotoxinas en postcosecha.
Aflatoxins are potent carcinogens that pose a significant threat to human health. Incidence of these mycotoxins in foodstuffs is high, thus their control and prevention is mandatory in the food industry. The development of appropriate predictive models that allow us to predict fungal growth and mycotoxin production will be a valuable tool to monitor, predict and prevent the mycotoxin risk. To develop accurate predictive models it is important to account for the real conditions that we will encounter through the food chain. Such conditions include: suboptimal conditions for growth and mycotoxin production, even distribution of spores across the food matrix, presence of different strains of the same species or dynamic environmental conditions. Given the scope and complexity of the problem the present work provides the basis for scientifically proven models, which can be applied in the food industry in order to improve postharvest control of commodities.
25
Guevara-Guerrero, Gonzalo. "Biological studies of shiitake logs and associated mycoflora in the Virginia highlands". Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-08142009-040430/.
Testo completo
26
Lavine, Ingrid Nadean. "Characterization of an Arsenate-Reducing Bacterium Strain NP4, Isolated from Groundwater in Northport, Maine". Fogler Library, University of Maine, 2004. http://www.library.umaine.edu/theses/pdf/LavineIN2004.pdf.
Testo completo
27
Newton, Giles H. "Investigation of the molecular mechanisms that regulate the qut gene cluster of Aspergillus nidulans". Thesis, University of Newcastle Upon Tyne, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320026.
Testo completo
28
Chaure, Pushpalata Trimbak. "A regulatory role for acetyl-CoA synthetase (acu-5) in Neurospora crassa". Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239059.
Testo completo
29
Cox, Philip William. "Application of image analysis to fungal fermentations". Thesis, University of Birmingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364884.
Testo completo
30
ICENHOUR, CRYSTAL RENEE PERRY. "EXPERIMENTAL EVIDENCE FOR COMPETITIVE COEXISTENCE OF TWO SPECIES OF PNEUMOCYSTIS WITHIN RAT LUNGS". University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1012244966.
Testo completo
31
Gilfillan, Gregor D. "Virulence and signal transduction of hypha formation in Candida albicans". Thesis, University of Aberdeen, 1999. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU112191.
Testo completoAbstract (sommario):
The aims of this work were to investigate the signal transduction pathways controlling the yeast-hyphal morphological transition of Candida albicans, and to gain a clearer understanding of the importance of hyphal formation of the virulence of this organism. The work can be divided into two areas. Firstly, the recently discovered species Candida dubliniensis, the only species in addition to C. albicans capable of forming true non-constricted hyphae, was examined in comparison to C. albicans to compare their virulence capability in vitro and in vivo. The two species were compared with respect to hypha formation, adherence, possession of SAP genes and virulence in the mouse model of systemic candidosis. C. dubliniensis possessed at least a homologue to each of the nine known C. albicans SAP genes, adhered to human cells to a greater degree on exposure in glucose, formed hyphae slightly less efficiently than C. albicans and was less virulent in mice. C. dubliniensis has been isolated particularly from the mouths of HIV positive and AIDS patients. The results of the virulence assessment could be interpreted as reflecting its epidemiological occurrence, - increased adherence on exposure to glucose may be a response to dietary sugar and the reduced virulence would explain in part its association with immunocompromised hosts. Secondly, the role of phosphoinositide signalling in control of the yeast-hyphal transition was investigated by the cloning and characterisation of two putative phosphatidylinositol 4-kinase genes from C. albicans, named CaPIK1 and CaPIK2. Both genes were cloned through their homology to the S. cerevisiae PIK1 gene. Disruption of the CaPIK1 gene in C. albicans indicated that it had no obvious role in the control of hypha formation.
32
Low, Gordon Alister. "An investigation of selected effects of environment on the dry rot fungus, Serpula lacrymans". Thesis, Abertay University, 2000. https://rke.abertay.ac.uk/en/studentTheses/5f450e84-358d-4c10-b234-733cf2e67d4f.
Testo completoAbstract (sommario):
Comparisons were made between the sensitivities of unique ‘wild’ isolates and domestic isolates of the dry rot fungus, Serpula lacrymans, to temperature, water potential and pH. Comparisons were also made between their capacities of timber decay. The ‘wild’ Himalayan isolates displayed slightly less marked sensitivities to high and low temperature and lowered water potential, yet the isolates were equally tolerant of pH. In general, the linear growth rates of the domestic isolates proved to be twice those of the ‘wild’ Himalayan set, whereas little variation occurred between their rates of timber decay. This study also resulted in the first isolation and reliable identification of ‘wild-growing’ S. lacrymans collected in Europe. The main part of the project involved the construction of novel chambers in order to examine the effects of lowered humidity and moving air flow on the activity of S. lacrymans. In the smallest and simplest of these, its growth and timberdecaying activities could be stopped by incubation at 86% relative humidity or by the application of a pumped air flow rate of 2.5 litres per minute; however, S. lacrymans was not inactivated until more-stressful conditions were applied. In addition, an intermediate rate of air flow provoked marked directional growth away from the stress. Furthermore, the introduction of stone, brick and plaster into these models encouraged the capacities of timber decay and mycelial growth. The use of a larger and more representative model incorporating simulated flooring and plaster walling within glass tanks revealed differences in the appearances and patterns of colonisation by S. lacrymans depending upon whether aged or new materials were used. Treatments involving air drying by fans caused both a shrivelling and a loss of viability of the fungus only when there was no ‘reservoir’ of water available; when there was water present, latent activity remained. An elaboration of this experimental design tested the effects of a combined biological and environmental treatment. Subsequently, the application of Trichoderma harzianum, a known antagonist of S. lacrymans, proved not to be an effective remedial treatment on its own, but appeared to impart a mildly protective effect when combined with a drying regime. Importantly, in the latter situation T. harzianum caused a severe degradation of the part of the colony responsible for the uptake of water in S. lacrymans. Another workshop-scale model simulating more authentically a damp sub-floor space and a cavity behind aged plaster walling was developed. When respective treatments by fan drying and passive ventilation were compared, the former were more effective, but its efficacy could be augmented by incorporating low-level passive ventilation via discreet vents. In this manner, a successful remedial treatment of S. lacrymans could be effected, though the prevalence of mould could prove to be undesirable in practice. However, some samples of this displayed antagonistic effects against S. lacrymans. A further experiment was designed to test the effects of air drying on the production of the stress-protective carbohydrate trehalose and of some associated solutes by S. lacrymans. In contrast to reports of some other organisms, no definite stockpiling of any of the compounds occurred. A final series of experiments revealed that S. lacrymans removed calcium, silicon and iron from sandstone and calcium, sulphur and iron from aged plaster; these elements were sequestered on its hyphae, especially in the form of calcium oxalate. Degradation of the sandstone was implicit but not obvious microscopically. Furthermore, S. lacrymans transported iron from these building materials through its mycelial system. An attempt to determine the effects of separate minerals in sandstone and plaster on timber decay revealed few variations.
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Carlisle, Diane Jean. "The diversity of the Phytophthora infestans population in Northern Ireland". Thesis, Queen's University Belfast, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322769.
Testo completo
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Lyne, Michael Harvey. "Cloning and characterisation of a meiosis-specific gene, pck1, from the fission yeast Schizosaccharomyces pombe". Thesis, University of Exeter, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260618.
Testo completo
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Kasuga, Takao. "Molecular probes for identification of intersterility groups of the wood rot fungus Heterobasidion annosum". Thesis, University of Aberdeen, 1995. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU068827.
Testo completoAbstract (sommario):
Heterobasidion annosum (Fr.) Bref., is a pathogenic hymenomycete which causes white-rot of coniferous trees throughout temperate regions of the Northern Hemisphere. The fungus can be divided into three intersterility groups (IS-groups) in Europe and two IS-groups in North America based on in vitro sexual compatibility and, loosely, on host tree preference. European P, S and F IS-groups prefer pine, spruce and fir respectively, and North American P and S groups prefer pine and fir respectively. This work describes the identification of discriminating characters which reflect underlying genetic differences accumulated between the IS-groups. Two genetic loci in the ribosomal DNA repeat and RFLPs in total genomic DNA were examined. Intraspecific divergence was found in the DNA sequence of PCR amplified internal transcribed spacer region (ITS) in ribosomal RNA repeat unit. It was found that various mutation detection techniques such as RFLP, single strand DNA conformation polymorphism (SSCP), heteroduplex DNA polymorphism and amplification refractory mutation system (ARMS) were applicable for the detection of base variations in the ITS region and therefore for the identification of IS-groups. However, since European S and F strains are genetically closely related to each other, these two were not unequivocally distinguishable. Intergenic spacer region (IGS) in the rRNA repeat unit in H. annosum was also amplified by PCR. The five IS-groups were distinguished by RFLP analysis of the IGS region, though there remained some European S and F group isolates which were also identical at this locus. RFLP in total genomic DNA was seen on ethidium bromide stained agarose gel after electrophoresis and found to be able to differentiate the European IS-groups unambiguously. RFLPs in total genomic DNA revealed with minisatellite probes were also found to be useful for IS-group identification.
36
Barker, Bridget M. "POPULATION GENETICS AND GENOMICS OF COCCIDIOIDES IMMITIS AND COCCIDIOIDES POSADASII". Diss., The University of Arizona, 2009. http://hdl.handle.net/10150/193909.
Testo completoAbstract (sommario):
The goal of my dissertation research is to elucidate the population structure of two understudied but increasingly important fungal pathogens of humans. Coccidioides immitis and C. posadasii cause the disease coccidioidomycosis (Valley fever). These fungi occur in the soil of the desert regions of North and South America. Although studied for over 100 years, the primary host, ecological niche, and sexual cycle of Coccidioides spp. still remain unknown. Understanding the population structure of these fungi will permit identification of fundamental aspects of their ecology and allow researchers to identify potential hosts. Assessing genotypic diversity of pathogens is one step to understanding the population structure and evolutionary potential of organisms, and is the focus of this dissertation. The first appendix focuses on developing and evaluating methods to obtain environmental samples, and comparison of genotypes found in soil vs. human patients. Direct inoculation of mice proved to be the most reliable method of obtaining environmental strains. Environmental isolates from Tucson group with Arizona patient isolates. Comparing genotypes of human, environmental and non-human host strains of Coccidioides may help to determine if gene flow occurs over long distances and provide some indication of the population structure of C. posadasii in the environment, and is the focus of the second appendix. Finally, whole-genome sequencing and resequencing has been completed for 20 strains of C. immitis and C. posadasii. The resulting data provide greater insight into variation between and within species. In particular, the final appendix provides evidence for hybridization and gene flow between species. Data show that a region of C. posadasii origin is found at a higher frequency among the C. immitis southern California and Mexico patient isolates, and is found rarely among patient isolates from the San Joaquin Valley. Of particular interest is the fact that there is a conserved border region for all instances of introgression, and the gene immediately adjacent to this border is a metalloproteinase gene. Together these studies provide insight into the population biology of two human pathogenic fungi: gene flow is limited between species and populations, but genetic exchange occurs at all levels.
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Sindle, Astrid Elizabeth. "Evaluation of the effect of morphological control of dimorphic Mucor circinelloides on heterologous enzyme production". Thesis, Link to the online version, 2006. http://hdl.handle.net/10019/1207.
Testo completo
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Vandegrift, Andrew. "Ecological Roles of Fungal Endophytes". Thesis, University of Oregon, 2016. http://hdl.handle.net/1794/20401.
Testo completoAbstract (sommario):
Endophytic fungi live within tissues of plant hosts without causing symptoms of disease. These fungi are broadly split into the taxonomically and ecologically cohesive Clavicipitaceous endophytes, which infect grasses, and the taxonomically diverse non-Clavicipitaceous endophytes, which are found in nearly all plants and have diverse ecological strategies. My dissertation has two sections: Section A investigates the intersection of Clavicipitaceous endophyte ecology with other ecological theory, including invasion ecology (Chapter II) and community ecology and climate change (Chapter III); Section B investigates the ecology of one group of non-Clavicipitaceous endophytes, the Xylariaceae, using a culture-based study in Ecuador (Chapter IV) and a next-generation sequencing based endophyte survey in Taiwan (Chapter V). Section B is centered on testing the Foraging Ascomycete (FA) hypothesis—the idea that some decomposer fungi may adapt an endophytic lifestyle to escape limitations in primary substrate in both time and space.
In Chapter II, I utilized a host-specific Epichloë endophyte present ubiquitously in the European native range of the Pacific Northwest (PNW) invasive grass Brachypodium sylvaticum to test theories of invasion. In Chapter III, I examined the grass Agrostis capillaris in the context of a climate manipulation experiment in prairies in the PNW to elucidate patterns of interaction between multiple symbionts (Epichloë endophytes, dark septate root endophytes, and arbuscular mycorrhizal fungi) within single hosts across climatic variation.
In Chapter IV, I began to test the FA hypothesis by examining spatial relationships of Xylaria endophytic fungi in the forest canopy with Xylaria decomposer fungi on the forest floor in a remote Ecuadorian cloud forest. In Chapter V, I build on the results from the previous study, using a novel technique to examine spatial ecology of the Xylariaceae, pairing traditional mycological collection with the preparation of a next-generation sequencing metabarcode library of endophytes over a much greater area.
This dissertation includes previously published and unpublished coauthored material.
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Caitano, Cinthia Elen Cardoso. "PATOGENICIDADE DE Lecanicillium fungicola EM Agaricus bisporus /". Jaboticabal, 2020. http://hdl.handle.net/11449/192648.
Testo completoAbstract (sommario):
Orientador: Diego Cunha ZiedResumo: O fungo Lecanicillium fungicola é um importante patógeno no cultivo de Agaricus bisporus, apresentando diversos sintomas e perdas de produção. O objetivo do trabalho foi avaliar interações in vivo e in vitro dos fungos Lecanicillium fungicola e Agaricus bisporus. Os experimentos in vitro foram feitos utilizando discos de micélio do patógeno e composto colonizado pelo A. bisporus. O composto colonizado também foi utilizado para a frutificação de cogumelos tanto em tamanho menor em placas de petri como em maior quantidade. Foram aplicados quatro suspensões de esporos L. fungicola nos cogumelos em placas de petri, de acordo com o seu tratamento. Não ocorreu a paralisação do crescimento micelial in vitro no momento em que o patógeno e o hospedeiro se encontram. Após 36 horas a inoculação do patógeno foi possível a visualização de manchas no píleo e após 60 horas a visualização de hifas e esporos. A linhagem coloração creme apresentou maior massa e diâmetro do píleo e menor porcentagem de rompimento do véu. A linhagem de A. bisporus de coloração branca obteve maior produtividade do que a linhagem de coloração creme. O isolado LF 19/03 apresentou maior agressividade em ambas as linhagens de A. bisporus. Os diversos sintomas encontrados no decorrer da pesquisa possibilitaram a confecção de uma escala diagramática para auxiliar o produtor na comercialização dos cogumelos doentes.
Abstract: The fungus Lecanicillium fungicola is an important pathogen in the cultivation of Agaricus bisporus, presenting several symptoms and production losses. The objective of the work was to evaluate interactions in vivo and in vitro of the fungi Lecanicillium fungicola and Agaricus bisporus. The in vitro experiments were done using mycelium discs of the pathogen and compound colonized by A. bisporus. The colonized compost was also used for the fruiting of mushrooms both in smaller size in petri dishes and in greater quantity. Four suspensions of L. fungicola spores were applied to the boxes according to their treatment. Mycelial growth did not stop in vitro at the time the pathogen and host meet. After 36 hours the inoculation of the pathogen made it possible to see spots on the cap and after 60 hours, to view hyphae and spores. The cream-colored lineage showed greater mass and diameter of the cap and lesser percentage of rupture of the veil. The white colored A. bisporus strain obtained higher productivity than the cream colored strain. The isolate LF 19/03 showed greater aggressiveness in both strains of A. bisporus. The various symptoms found in the course of the research enabled the production of a diagrammatic scale to assist the producer in the sale of sick mushrooms.
Mestre
40
Bonetto, Valentina. "From cell to organism: an overview of responses to simulated hypergravity and microgravity". Doctoral thesis, Università del Piemonte Orientale, 2022. http://hdl.handle.net/11579/144698.
Testo completo
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Talarico, Claudio. "Leveduras em trato intestinal de população pediátrica hospitalizada". Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/9/9136/tde-22052015-171831/.
Testo completoAbstract (sommario):
Nas últimas décadas, houve aumento progressivo das infecções hospitalares por leveduras principalmente, do gênero Candida. A fonte de infecção pode ser endógena ou exógena, desde que esporos unicelulares de leveduras, permanecem viáveis por meses sobre superfícies bióticas ou abióticas. Diversas espécies de leveduras são encontradas em pele e mucosas de indivíduos sadios. Em estado saprofítico ainda, as leveduras encontram-se no trato gastrintestinal humano mas, a relação entre a presença desses microorganismos e sua patogenicidade está associada a diversos fatores predisponentes, tais como: número e variedade de sítios topográficos colonizados, uso prolongado de antibióticos, infecções associadas causadas por outros microorganismos e particularmente, distúrbios imunológicos ou metabólicos. Leveduras do trato gastrintestinal podem ser transmitidas, via fecal-oral diretamente ou de modo indireto, de indivíduo para indivíduo. A transmissão de uma cepa em estado saprofítico para um hospedeiro suscetível, pode resultar em colonização seguida de infecção. A gravidade do quadro clínico depende de condições do hospedeiro e características do agente etiológico que engloba fatores de virulência e resistência a antifúngicos. Esses atributos são importantes em Candida albicans na qual, enzimas com atividade de fosfolipase e proteinase são marcadores de virulência. De outro modo, fenótipos de resistência, ocorrem, com maior freqüência, em espécies não-Candida albicans. Dada a possibilidade de instalação de doença endógena e a dispersão de cepas virulentas e resistentes, a partir de colonização gastrintestinal, estudos que contribuam para a determinação desses agentes constituintes da microbiota de pacientes internados, são importantes para o conhecimento da história natural das infecções nosocomiais por leveduras. Os objetivos deste trabalho foram avaliar o trato intestinal como fonte potencial de infecção hospitalar por leveduras, descrevendo as espécies prevalentes nas primeiras horas de internação e possíveis alterações temporais, quanto a fenótipo de virulência e resistência a antifúngicos. Foram analisadas 281 amostras de leveduras isoladas de 66 crianças internadas em unidades de pediatria e semi-intensiva de hospitais públicos das cidades de São Paulo e Guarulhos, Brasil. As amostras foram isoladas de fezes coletadas nas primeiras horas de internação e durante o período de internação. A identificação das leveduras quanto a gênero e espécie foram realizadas por métodos tradicionais, analisando aspectos morfológicos e fisiológicos. A capacidade de produção de enzimas, fosfolipase e proteinase, foram verificadas conforme proposto por Price et al. 1982 e Ruchël et al., 1982. A sensibilidade aos antifúngicos: anfotericina B (AMB), fluconazol (FZ), itraconazol (IZ), cetoconazol (CZ) e nistatina (NIS) foram analisada pela técnica de difusão por discos (CECON São Paulo, Brasil). Amostras resistentes ou com sensibilidade intermediária, foram re-avaliadas pelo método de microdiluição segundo NCCL (1997) modificado por EUCAST (2002). As espécies isoladas foram: Candida tropicalis (32,7%), C.albicans (29,9%), C.parapsilosis (27, 1%), Trichosporon cutaneum e T.inkin (3,2%), Rhodotorula mucilaginosa e R.glutinis (0,7%), C.krusei (3,6%), C.guilliermondii (2,1%), C.glabrata (0,4%) e C.kefyr (0,4%). A atividade enzimática foi observada na maioria das 84 amostras de C. albicans, sendo 96% de fosfolipase e 95% de proteinase. Entre as espécies não-albicans do gênero Candida foi verificada atividade em 97% de fosfolipase e 67% de proteinase. Amostras menos sensíveis às drogas azólicas, ou seja, amostras resistentes ou com sensibilidade dependente da dose, foram encontradas em 4,3% das 281 amostras de leveduras, sendo maior porcentagem observada em C.krusei (90%). Conclui-se que existem leveduras de diversas espécies em fezes de população pediátrica hospitalizada, com fenótipos de virulência e resistência a antifúngicos. A manutenção desses fenótipos durante o período de internação pode representar fator de risco para infecção hospitalar endógena, ou ainda, fonte de dispersão de patógenos em potencial, no meio ambiente hospitalar.At the last decades the nosocomial infections caused by yeasts raised significantly especially by Candida yeasts. The infections source can be endogen or exogenous, since spores of unicellular and multicellular are kept viable for months and several yeasts species are found in skin and mucosa of healthy people. In a saprophytic state yeasts are found in the human gastrointestinal tract but the relationship between the presence of these microorganisms and their pathology is associated with several facts such as: number, variety of sites colonized, effective use of antibiotics, associated infections caused by another microorganisms and mainly disturbance in due to lack of immunity and metabolic. Yeasts in the gastrointestinal tract can be transmitted fecal-oral direct or indirectly from an individual to another. The transmission of a strain in a saprophytic state to a host can result in colony followed by infection. The infection can be serious depending on the host conditions and the etiologic agent that includes virulent factor and resistance to antifungal drugs. These attributes are important to Candida albicans in which enzymes with phospholipase activity are responsible for virulent factors. Resistance phenotypes, otherwise it should occur more frequently in non-albicans species. Concerning the possibility of an endogen disease and the spread of virulent and resistant strains, from the gastrointestinal colony, studies that contribute to determine these agents that constitute the microbiota of patients, are important to know the natural story of nosocomial infections caused by yeasts. This work aims at evaluating the intestinal tract as a source of hospital infections by yeasts describing the remaining species in the first hours and a possible change depending on the time that may happen to virulent phenotypic and resistance to ant fungi. Two hundred eighty one yeast samples from sixty-six children attended in pediatric and semi-intensive units in 2 public hospitals located in São Paulo and Guarulhos cities in Brazil were analyzed. The fecal samples were collected at the first hours after and during their arrival at the hospital. To identify the yeasts according to their gender and species traditional methods were used, analyzing morphological and physiological aspects. The ability to produce enzymes phospholipase and proteinase was verified the same way it was proposed by Price et al. 1982 and Ruchel et al. 1982. The sensibility to antifungals: amphotericin B (AMB), f1uconazole (FZ), ketoconazole (CZ) e nistatin (NIS), was analyzed by the diffusion technical by disks (CECON São Paulo, Brazil). Resistant samples or with intermediate sensibility were confirmed by micro-dilution method according to NCCLS (1997) modified by EUCAST (2002). The isolated species were: Candida tropicalis (30%), C.parapsilosis (27%), C.krusei (4%), Trichosporon cutaneum e T.inkin (3%), Rhodotorula mucilaginosa e R.glutinis (2%), C.guilliermondii (2%), C.glabrata (1%) and C.kefyr (1%). Enzymatic activity was verified in most of the 84 C.albicans samples being 96% of phosfolipase and 95% of proteinase production. Among the non-albicans species of Candida it was observed 97% of phospholipase and 67% of proteinase activity. Less sensitive samples to azoic drugs including resistant or SDD sensibility, which depends on the achieved dose, were found in 4.3% of the 281 samples of yeast. The hugest percentage was observed in C.krusei (90%). We can conclude that different yeast species occur in stools of pediatric population hospitalized, including virulent strains and antifungal resistant phenotypes. The persistent of these phenotypes in the intestinal tract during hospitalization period may represents a risk facto r contributing to endogen infection, or play a role in dissemination of potential pathogens inside a nosocomial environment.
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Bet, Diego Leonardo. "Padrões de dermatoscopia da placa ungueal nas onicomicoses". Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/5/5133/tde-23092015-115531/.
Testo completoAbstract (sommario):
INTRODUÇÃO: Onicomicose é a infecção fúngica das unhas e é considerada a onicopatia mais frequente em adultos. Representa até 50% das lesões ungueais, sendo necessária confirmação diagnóstica com exame complementar que demostre a presença do fungo na unha, sendo o exame micológico direto e a cultura para fungos os mais utilizados. A dermatoscopia é um exame não invasivo, rápido e de baixo custo cujos padrões para onicomicose relatados na literatura em estudos retrospectivos chegam a 100% de sensibilidade e especificidade. Deste modo realizamos um estudo prospectivo para comparar a dermatoscopia frente ao exame micológico. MÉTODOS: Estudo prospectivo, transversal avaliando 109 pacientes e 202 unhas com suspeita diagnóstica de onicomicose. Os padrões dermatoscópicos encontrados foram descritos através de fotografias digitais. A sensibilidade e especificidade dos padrões de onicomicose distal-lateral foram determinados de acordo com o resultado do exame micológico. RESULTADOS: Foram significativos (p < 0,05) para o diagnóstico de onicomicose distal lateral e tiveram sensibilidade/especificidade calculadas os padrões: borda recortada (80,2% / 65,3%), borda linear (12,6% / 42,9%), estrias irregulares (81,1% / 65,3%), estrias finas/regulares (9,9% / 59,2%); e as cores branco (93,7% / 18,4%), amarelo (63,1% / 71,4%) e laranja (10,8% / 100%). Após análise multivariada stepwise forward os padrões de estrias irregulares, borda linear e cor amarela mantiveram significância estatística (p < 0,05). DISCUSSÃO: Os achados deste trabalho prospectivo estão de acordo com a literatura mostrando que há correlação entre o exame micológico e a dermatoscopia. Todavia, não ratifica a sensibilidade e especificidade de 100% encontrada em estudo retrospectivo para os padrões de borda recortada e borda linear. Também não demonstrado na literatura, as cores amarela, branca e laranja foram também estatisticamente significativas para o diagnóstico. CONCLUSÃO: A dermatoscopia correlaciona bem com a história natural da infecção fúngica e com o exame micológico, sendo um exame promissor para o diagnóstico de onicomicose. Sugerimos que futuros estudos comparem a dermatoscopia com exames considerados padrão-ouro (ex: microscopia de fluorescência e PCR) para detectar exames falso negativosBACKGROUND: Onychomycosis is defined as a fungal infection of the nail and is considered the most common onychopathy in adults. It represents up to 50% of nail diseases and demonstration of the fungal pathogen is necessary for diagnostic confirmation. Direct mycological examination and fungal culture are commonly used for this purpose. Dermoscopy is a noninvasive, fast and inexpensive exam, reaching 100% diagnostic sensitivity and specificity for onychomycosis in retrospective studies. Thus, we conducted a prospective study to compare dermoscopy with mycological examination. METHODS Prospective, cross-sectional study with 109 patients and 202 nails evaluated. Dermoscopic patterns were described using digital photography and their sensitivity and specificity for distal-lateral onychomycosis were determined. RESULTS: Statistically significant (p < 0.05) patterns and colors for the diagnosis of distal-lateral onychomycosis and respective sensitivity / specificity: jagged edge (80.2% / 65.3%), linear edge (12.6% / 42 , 9%), longitudinal irregular streaks (81.1% / 65.3%), longitudinal fine / regular streaks (9.9% / 59.2%); white color (93.7% / 18.4%), yellow color (63.1% / 71.4%) and orange color (10.8% / 100%). After a stepwise forward multivariate analysis irregular streaks, linear edge and yellow color remained statistically significant (p < 0.05). DISCUSSION: Findings of this prospective study are in agreement with the literature showing that there is correlation between mycological examination and dermoscopy. However, this study does not agree with 100% sensitivity and specificity found in retrospective studies for jagged edge and linear edge patterns. In addition, white, yellow and orange colors were also statistically significant for the diagnosis of onychomycosis. CONCLUSION: Dermoscopy correlates well with the natural history of fungal nail infection and mycological examination, and we consider it a promising method for the diagnosis of onychomycosis. We suggest that future studies compare dermoscopy with a gold standard exam (ex: fluorescence microscopy, PCR) to detect false negative cases
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Nicolau, Manterola Felipe. "Hydrocarbon and insecticide induction of Beauveria bassiana catalysis of organosulfur compounds". Diss., University of Iowa, 2016. https://ir.uiowa.edu/etd/3151.
Testo completoAbstract (sommario):
Catalysts are utilized in 80% of all chemical synthesis operations. The industrial catalysts primarily used in oxidation reactions are highly polluting and expensive metal catalysts. Enzymes and whole cell biocatalysts are used to a lesser extent. Nowadays, several industrial sectors are developing bio-based technologies to reduce the high costs and environmental impact of traditional chemical processes. However, these applications are limited by the challenge of developing economically competitive biologically based systems. The key for adopting these sustainable advancements is the development of novel process designs, which assure robustness, simplicity, and sustainabile operations compatible with the current development of chemical reactions. In this regard, filamentous fungi may be considered good biocatalysts due to their natural biodiversity and their broad heterogeneous enzymatic pattern. The great selectivity of fungal catalysis is now well recognized for the production of commercially valuable steroids in the pharmaceutical industry. Although this inherent capacity is mainly used for functionalization of unactivated carbons, it can be further exploited for the oxidiation of heteroatoms, such as sulfur. Focusing on the oxidation of sulfur compounds, the widely used industrial processes are produced by an organometallic catalyst. This PhD project aims to overcome low substrate conversion and enzymatic expression by proving that exposure of cells to insecticides and hydrocarbons increases cell's oxidative capacity expressed as higher substrate conversion and CYP450 content. This study is focused in the application of pest management strategies, designed to enhance the biopesticide's efficacy, to induce and improve Beauveria bassiana oxidation. B. bassiana has a very flexible metabolism and is widely used as a biocontrol agent. It can metabolize hexadecane as a sole carbon source. In addition, it shows a synergistic effect over pest control efficacy when it is applied with low pesticides (carbaryl and/or imidacloprid) concentrations.
A biocatalytic system was optimized to increase the conversion of organosulfur compounds under different fermentation conditions. Phenothiazine was used as our model substrate. Phenothiazine conversion was followed by GC-MS and HPLC. By NMR and MS fragmentation pattern product, phenothiazine metabolites were identified as (R)-hydroxyl metabolites (63% enatiomeric excess) and sulfoxide, the latter being the main metabolite. Phenothiazine conversions with growing cells resulted in 65±1.4% conversion with initial phenothiazine concentration of 500 ppm and final 325 ppm after 7 days. The highest conversion, 74±1 % was achieved with resting cells at the lowest cell concentration, 0.78 mg cell dry weight (cdw) /mL. Furthermore, the use of insecticides as inducers was an effective way to increase phenothiazine conversion from 47% to 64±3%. The major enzymes involved in catalysis of xenobiotic are heme-binding monooxygenases, in particular cytochrome P450. Heme positive proteins were identified by an SDS benzidine assay as well as the content of CYP450 by the CO difference spectrum. The P450 enzymes content was 12.3±1 pmol/µg protein for hexadecane adapted cells and 8.1± 1 pmol/µg protein for insecticides, respectively. The heme-positive proteins were characterized by MALDI-ToF and their peptide mass fingerprint compared to the available sequences on the SwissProt/Universal Protein Resource catalog of information on proteins (UniProtKB). Hemoproteins were found, including a cluster of catalase-peroxidase, alkane hydroxylase, and chloroperoxidase. The results from this project helped bridge the progress from agricultural biotechnology strain development into industrial biotechnology biocatalyst improvement. The success of this project helps us expand B. bassiana's catalysis and make it a better candidate for industrial biocatalysis.
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Hérivaux, Anaïs. "Les récepteurs histidine kinases : structure et distribution chez les eucaryotes et caractérisation fonctionnelle chez l’espèce Scedosporium apiospermum rencontrée au cours de la mucoviscidose". Thesis, Angers, 2018. http://www.theses.fr/2018ANGE0030.
Testo completoAbstract (sommario):
Les histidine kinases (HKs) représentent une vaste famille de protéines impliquées dans la perception des signaux environnementaux chez les bactéries, les champignons et les plantes. Ces protéines joueraient notamment un rôle majeur dans l’adaptation aux stresses, mais aussi dans la virulence de nombreux micro-organismes procaryotes et eucaryotes. Si les HKs sont à présent bien connues chez les bactéries et les plantes, tant sur un plan structural que fonctionnel, les connaissances concernant ces protéines chez les autres clades de l’arbre du vivant demeurent plus que fragmentaires. C’est ainsi que le premier objectif de ce travail a consisté en l’exploration in silico de la structure et de la distribution des HKs chez les organismes eucaryotes dans le cadre de plusieurs études bioinformatiques : i) chez les champignons inférieurs, ii)chez les levures bourgeonnantes et enfin iii) à travers l’ensemble des super-groupes eucaryotes. Les HKs n’étant pas retrouvées chez les mammifères, elles suscitent depuis quelques années une attention particulière de la communauté scientifique en tant que nouvelles cibles pour le développement d’antimicrobiens. C’est précisément dans ce contexte que la partie expérimentale de ce projet a été initiée au sein du GEIHP. Cette équipe porte en effet ses efforts sur le filamenteux multi-résistant Scedosporium apiospermum qui se situe au second rang parmi les moisissures capables de coloniser chroniquement les poumons des patients atteints de mucoviscidose. Ainsi, dans l’optique d’identifier de nouvelles cibles thérapeutiques du champignon, la seconde partie de ce projet s’est focalisée sur la caractérisation fonctionnelle des HKs chez Scedosporium apiospermum. En parallèle, cette étude nous a également amenés à développer de nouveaux outils moléculaires adaptés à S.apiospermum en vue de futures études d’imageries de fluorescence et de bioluminescenceHistidine kinases (HKs) represent a broad family of proteins involved in the perception of environmental signals in bacteria, fungi and plants.These proteins play a major role in stress adaptation, but also in the virulence of many prokaryotic and eukaryotic microorganisms. Although HKs are now well known in bacteria and plants, both structurally and functionally, knowledge about these proteins in other clades of the living tree remains more than fragmentary. Thus the first objective of this work was the in silico exploration of the structure and distribution of HKs in eukaryotic organisms through several bioinformatics studies : i) in the lower fungi, ii)in budding yeasts, and finally iii) across all eukaryotic supergroups. Since HKs are not found in mammals, they have been attracting attention in recent years from the scientific community as new targets for the development of antimicrobials. It is precisely in this context that the experimental part of this project was initiated in the GHEIHP. This team is focusing on the multi-resistant filamentous Scedosporiumapiospermum, which ranks second among the molds capable of chronycally conolizing the lungs of cysticfibrosis patients. Thus, in order to identify new therapeutic targets of the fungus, the second part of this project focused on the functional characterization of HKs in S. apiospermum. In parallel, this study also led us to develop new molecular tools adapted to S. apiospermum for future studies of fluorescence or bioluminescence imaging
45
Thomas, Daniel. "Hitchhiking in the Canopy: Ecological Patterns of Forest Mycobiomes". Thesis, University of Oregon, 2018. http://hdl.handle.net/1794/23141.
Testo completoAbstract (sommario):
The fungal microbiome, or “mycobiome” of plants is diverse and important to
host health, but the fluxes of fungi among plant hosts and with the surrounding
environment are poorly understood. In chapter two, we employed sterile culture
techniques and spatial sampling to examine leaves as possible vectors for transfer of their
endophytic fungi from the canopy to substrate on the forest floor, as predicted by the
Foraging Ascomycete hypothesis. Some foliar endophytic fungal species are also present
as wood-decomposing fungi on the forest floor, that transfer of mycelium across these
two life history stages can occur, that endophytic life history stages are buffered from
environmental conditions in comparison to wood-decomposing fungi, and that spatial
linkages between the two life history stages can be observed. In another study, described
in chapter 3, wood and leaf wood endophytes were sampled across a 25 ha plot, to
explore landscape patterns of mycobiomes, and to explore the concept of a core
microbiome in aerial plant tissues. We found that core microbiomes may be observed in a
real ecological setting, but that the concept of core must be carefully defined and that
some level of buffering from disturbance may be necessary to allow core microbiomes to
assemble. In chapter four, we return to examine some of the assumptions and
implications of the Foraging Ascomycete hypothesis, with an agent-based model. We
model the conditions under which dispersal through falling leaves may represent a
fitness-enhancing dispersal strategy for fungi, and that deforestation as is currently
underway throughout the world may have impacts on fungi that rely upon a canopy-
inhabiting life stage for dispersal. In chapter five, some challenges associated with
environmental sampling of microbes using illumina© MiSeq sequences are critically
examined. We find that biases introduced by random sampling at various stages of
IVenvironmental DNA extraction and illumina© MiSeq sequencing are not well corrected
by currently accepted bioinformatic algorithms. In addition, information loss from
differential extraction, PCR amplification, and sequencing success, requires that users of
MiSeq read libraries to interpret read abundances carefully.
This dissertation includes previously published, co-authored material.
46
Voltan, Aline Raquel [UNESP]. "Determinação de genes/proteínas endossomais em Paracoccidioides brasiliensis e em macrófagos infectados e não infectados". Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/103858.
Testo completoAbstract (sommario):
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000715398.pdf: 978625 bytes, checksum: f9f26554857da3d03570f04ef587630d (MD5)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Os fungos dimórficos, Paracoccidioides brasiliensis (espécies cripticas S1, PS2, PS3) e Paracoccidioides lutzii (Pb01-like espécies), são agentes da paracoccidioidomicose (PCM), doença granulomatosa crônica, endêmica na América Latina, principalmente no Brasil. A doença apresenta grande variedade de manifestações clínicas, desde formas localizadas até disseminadas evoluindo para letalidade. O fungo tem capacidade de aderir, invadir e extravasar barreiras impostas pelos tecidos do hospedeiro. P. brasiliensis (Pb18) já foi observado tanto no interior de macrófagos, como no interior de células epiteliais in vivo e in vitro. A identificação do mecanismo pelo qual este fungo sobrevive no interior da célula hospedeira é campo fértil para a descoberta de sua patogênese, já que este microrganismo possui a capacidade de induzir sua própria endocitose em células epiteliais e muito provavelmente em macrófagos. A absorção de micronutrientes pelo fungo apresenta papel singular, tanto para sua nutrição e processo invasivo, como para sua sobrevivência no interior da célula hospedeira. A via endocítica em microrganismos é de fundamental importância na regulação de todo esse processo. O objetivo deste estudo foi avaliar a via endocítica de Pb18 e também de macrófagos infectados com este fungo. A avaliação da via endocítica de Pb18 foi realizada na condição de depleção de metais, onde foram analisados os genes Clatrina e Ypt7 (Homólogo de Rab7) por RT-PCR semi-quantitativo e PCR em tempo real (RT-PCR quantitativo). Também foi analisada a infecção de macrófagos por Pb18 cultivado na depleção de metais e em diferentes tensões de oxigênio. A via endocítica de macrófagos foi analisada por RT-PCR quantitativo e imunofluorescência. Esta análise foi realizada quando o fungo foi cultivado em...
The dimorphic fungus, Paracoccidioides brasiliensis (cryptic species S1, PS2, PS3) and Paracoccidioides lutzii (Pb01-like species), are agents of paracoccidioidomycosis (PCM), chronic granulomatous disease, endemic in Latin America, especially in Brazil. The disease has a wide variety of clinical manifestations, from localized forms to disseminated evolving to lethality. The fungus is able to adhere, invade and spill barriers imposed by host tissues. P. brasiliensis (Pb18) has already been observed both within macrophages, but also inside of epithelial cells in vivo and in vitro. Identification of the mechanism by which this fungus survive within the host cell is a fertile field for the discovery of their pathogenesis, since this microorganism has the ability to induce its own endocytosis in epithelial cells and most probably in macrophages. The micronutrient uptake by the fungus presents unique role, both for its nutritional and invasive procedure, such as for survival within the host cell. The endocytic pathway in microorganisms is of fundamental importance in the regulation of this process. The aim of this study was to evaluate the endocytic pathway of Pb18 and also macrophages infected with this fungus. The evaluation of the endocytic pathway of Pb18 was performed under the condition that depletion of metals, where the genes were analyzed Clathrin and Ypt7 (Rab7 homolog) by RT-PCR semi-quantitative and real-time PCR (RT-PCR quantitative). Was also analyzed by Pb18 infection of macrophages cultured in the depletion of metals at different oxygen tensions. The endocytic pathway of macrophages was analyzed by quantitative RT-PCR and immunofluorescence. This analysis was performed when the fungus was grown at different oxygen tensions and macrophages were infected with this and when the infection was incubated at... (Complete abstract click electronic access below)
47
Filho, Renato Evando Moreira. "Micologia forense: a dinÃmica da microbiota fÃngica na investigaÃÃo do perÃodo post mortem". Universidade Federal do CearÃ, 2008. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=2981.
Testo completoAbstract (sommario):
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorWith developing of forensic observations, certain species of insects and microorganisms were described as indicators of periods of the degradation of the body. However, the literature is still scarce in the field of Forensic Mycology. It was investigated the microbiological characteristics of fungi presence in the post mortem change, as well as, it esteemed the value of the mycology exams in the study. 400 collections was accomplished in 60 human bodies (34 of the bloated stage, 06 of the putrefaction stage and 20 of the skeletonization stage) at the Fortaleza city morgue and public cemeteries in the state of CearÃ, The picked material was analyzed through macro/microcharacteristics and specific biochemical tests. Ally to such analyses, was also accomplished the test of the perforation of the hair in vitro in hair of corpses in the bloated stage and in hair of healthy adults. The material gathered was analyzed at the Specialized Medical Mycology Center of the Federal University of CearÃ. With the anthropological results, it was observed that male, in the interval of the 31 to the 40 years, was more commonly attacked, being the capital (Fortaleza) the more involved in the number of deaths. In the bloated stage, among the identified filamentous fungi, the presence of four orders was observed: Order Eurotiales (63 isolated Aspergillus spp and 21 isolated Penicillium spp), Order Mucorales (4 Mucor spp), Order Hypocreales (2 Acremonium spp, 1 Trichoderma spp and 1 Fusarium spp) and Order Saccharomycetales (2 Geotrichum spp). In the yeast distribution, it was observed the orders:Saccharomycetales (44 Candida spp) and Tremellales (5 Trichosporon spp). In the putrefaction stage, it was isolated the following orders: Eurotiales (Penicillium spp 2 and Aspergillus 2) and Hypocreales 1 (Acremonium spp). Regarding the yeasts, it was just isolated the Order Saccharomycetales (Candida spp 3). In the eskeletonization stage, the following orders were observed: Order Eurotiales (Aspergillus spp 22 and Penicillium spp 18), Order Mucorales (Mucor spp 10) and Order Hypocreales (Acremonium spp 2 and Trichoderma spp 1). Regarding the yeasts, two orders were found: Tremellales (Trichosporon spp 1) and Saccharomycetales (Candida spp 1). In the hair perforation test in vitro, it was positive in the bloated stage, differing of healthy adults,where the test was negative. For conclusion, Forensic Micology is still a rich field in data and fungi can come to be a tool in the aid of human post mortem diagnosis.
Com o evoluir das observaÃÃes mÃdico-legais, determinadas espÃcies de insetos e microrganismos foram descritos como indicadores de perÃodos da degradaÃÃo do corpo. Entretanto, a literatura cientÃfica ainda à escassa no campo da Micologia Forense. Assim, investigaram-se as caracterÃsticas microbiolÃgicas dos fungos partÃcipes na mudanÃa de flora post mortem em humanos, bem como estimou-se o valor da realizaÃÃo de exames micolÃgicos no estudo cronotanatolÃgico. Foram realizadas um total de 400 coletas em 60 corpos humanos (34 do perÃodo gasoso, 06 do coliquativo e 20 do esqueletizado) examinados no Instituto MÃdico-Legal de Fortaleza e em cemitÃrios do Estado do CearÃ. Foram realizados estudos macro/micromorfÃlogicos e testes bioquÃmicos especÃficos para cada grupamento fÃngico isolado. Aliado a tais anÃlises, foi tambÃm realizado o teste da perfuraÃÃo do pÃlo in vitro em pÃlos de cadÃveres no perÃodo gasoso e em pÃlos de adultos hÃgidos. Estas identificaÃÃes foram realizadas no Centro Especializado em Micologia MÃdica da Universidade Federal do CearÃ. Com os resultados antropolÃgicos, foi observado que o sexo masculino, dos 31 aos 40 anos, foi o mais comumente acometido, sendo a capital (Fortaleza) a mais envolvida no nÃmero de mortes. No perÃodo gasoso, dentre os fungos filamentosos identificados, foi observada a presenÃa de quatro ordens: Eurotiales (63 isolados de Aspergillus spp e 21 de Penicillium spp), Mucorales (4 Mucor spp) e Hypocreales (2 Acremonium spp, 1 Trichoderma spp e 1 Fusarium spp) e Saccharomycetales (2 Geotrichum spp). No referente Ãs leveduras, verificaram-se as ordens: Saccharomycetales (Candida spp 44) e Tremellales (Trichosporon spp 5). No perÃodo coliquativo, registraram-se as ordens: Eurotiales (Penicillium spp 2 e Aspergillus 2) e Hypocreales 1 (Acremonium spp). No referente Ãs leveduras, isolou-se apenas a Ordem Saccharomycetales (Candida spp 3). No perÃodo de esqueletizaÃÃo, verificaram-se as seguintes ordens: Eurotiales (Aspergillus spp 22 e Penicillium spp 18), Mucorales (Mucor spp 10) e Hypocreales (Acremonium spp 2 e Trichoderma spp 1). No referente Ãs leveduras, registraram-se duas ordens: Tremellales (Trichosporon spp 1) e Saccharomycetales (Candida spp 1). Quanto ao teste de perfuraÃÃo do pÃlo in vitro, a positividade foi observada no perÃodo gasoso, diferindo de adultos hÃgidos, em que foi negativa. Conclui-se que o estudo da Micologia Forense ainda à um campo rico em dados e que os fungos poderÃo vir a ser uma ferramenta complementar no estudo do tempo de morte em Medicina Legal.
48
Ferreira, Ari José Scattone. "Regulação da resposta transcricional a estresses ambientais em fungos: análise de \"microarrays\" de cDNAs de Trichoderma reesei". Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/46/46131/tde-14122006-114540/.
Testo completoAbstract (sommario):
A grande diversidade de organismos que hoje encontramos em nosso planeta se deve à adaptação às diferentes condições ambientais de cada nicho ecológico existente e à resposta adaptativa originária das mudanças dessas condições. Pode-se considerar que a etapa inicial do processo de adaptação seja a reprogramação da expressão gênica dum organismo como resposta imediata a uma nova condição ambiental. De fato parte do genoma de todos os organismos é dedicada à codificação de proteínas relacionadas ao controle dos efeitos nocivos criados por diferentes tipos de estresse como choque térmico, ou osmótico, estresse oxidativo, ou aqueles resultantes de altas concentrações de íons de metais pesados. De forma semelhante, a ausência, ou exaustão, de fontes de macronutrientes, como carbono, nitrogênio, fósforo ou enxofre, exige uma reorganização do padrão de expressão gênica para adequação às novas condições nutricionais, também sendo considerada um estresse ambiental. Visto que a maioria dos estudos de análise da expressão gênica em resposta a estresses ambientais realizados em fungos se refere às leveduras unicelulares Saccharomyces cerevisiae e Schizossacharomyces pombe, nos propusemos a estudar tal resposta no fungo filamentoso multicelular Trichoderma reesei. Dessa forma analisamos por meio da técnica de \"microarrays\" de cDNAs a expressão gênica de aproximadamente 2.000 transcritos desse organismo em resposta a choque térmico, à alta concentração de íons de cádmio II e à ausência de fonte de carbono, ou nitrogênio, por período de 2 horas. Em geral, as respostas aos estresses se compuseram da regulação negativa da transcrição de genes envolvidos em processos com alta demanda de energia como a síntese protéica, evidenciada pela repressão da expressão de genes de proteínas ribossomais e do anabolismo. Em contrapartida, genes codificando proteínas relacionadas à defesa celular, como chaperonas, tiveram sua expressão induzida. As respostas ao choque térmico e ao tratamento com cádmio II se mostraram bastantes semelhantes, enquanto a ausência de fonte de nitrogênio também induziu a expressão de genes relacionados à degradação de proteínas e nucleotídeos. Genes relacionados à utilização de reservas lipídicas foram induzidos tanto na ausência de fonte de carbono quanto de nitrogênio. Foram identificados reguladores transcricionais e componentes de vias de sinalização celular com expressão diferenciada frente a esses diferentes estresses ambientais. A maior parte dos genes cuja expressão se alterou em função dos diversos estresses ambientais estudados ainda não tem função celular conhecida, sendo essa observação, portanto, uma contribuição importante para sua anotação funcional. Uma vez que o fungo filamentoso Trichoderma reesei vem se tornando um organismo de valor biotecnológico por sua característica de alto poder de síntese e secreção de proteínas, esperamos que os dados apresentados forneçam um maior entendimento dos processos celulares desse organismo e possam subsidiar futuros projetos visando uma melhor adaptação do mesmo a ambientes industriais.The diversity of organisms found today in our planet is due to their adaptation to different environmental conditions present in each ecological niche, and to the adaptative response originated from changes in those conditions. The first step in the adaptation process is considered to be the reprogramming of gene expression as an immediate response to a new environmental condition. A fraction of the genome from all living organisms is dedicated to encoding proteins related to the control of deleterious effects created by different types of stresses like heat or osmotic shock, oxidative stress, or by the presence of high concentrations of heavy metal ions. Similarly, the absence or exhaustion of macronutrients as carbon, nitrogen, phosphorous or sulphur sources demand new patterns of gene expression in order to the organisms survive in a limited nutritional condition, which is also considered an environmental stress. Once the gene expression analyses in fungi as a response to environmental stresses have been widely studied in the yeasts Saccharomyces cerevisiae and Schizossacharomyces pombe, we proposed to study such response in the multicellular filamentous fungus Trichoderma reesei. To this purpose, we have utilized the cDNA microarray technique to analyze the gene expression of approximately 2,000 T. reesei transcripts in response to heat shock, to high concentration of cadmium II ions and to a 2-hour absence of carbon or nitrogen source. As a general response to the four studied stresses, we observed on one hand a negative transcriptional regulation of genes involved in processes that demand great amounts of energy, i.e. a negative regulation of protein synthesis, indicated by strong repression of ribosomal protein genes transcription, as well as a negative regulation of anabolism. On the other hand, genes that encode proteins associated with cellular defense, like chaperones, had their expression induced. The responses to heat shock and to cadmium poisoning were quite similar while nitrogen source absence also induced the expression of genes related to protein and nucleotide degradation. Genes implicated in the consumption of lipid reserves were induced in the absence of both carbon and nitrogen sources. We identified some transcription regulators as well as components of signal transduction pathways that have differential patterns of gene expression caused by these different environmental stresses. Most of the genes that had their expression altered in response to the studied environmental stresses has no known function yet. Their expression patterns towards such stresses are therefore an important contribution to their functional annotation. Since the filamentous fungus Trichoderma reesei has become a microorganism of biotechnological value for its high capacity of synthesis and secretion of proteins, we expect that the data presented on this work can provide a better understanding of its cellular processes and may support future projects for a better adaptation of this organism to industrial conditions.
49
Voltan, Aline Raquel. "Determinação de genes/proteínas endossomais em Paracoccidioides brasiliensis e em macrófagos infectados e não infectados /". Araraquara, 2013. http://hdl.handle.net/11449/103858.
Testo completoAbstract (sommario):
Orientador: Maria José Soares Mendes GianniniCoorientador: Ana Marisa Fusco Almedia
Banca: Gil Benard
Banca: Marcelo Pelajo Machado
Banca: Christiane Pienna Soares
Banca: Raquel Mantuaneli Scarel Caminaga
Resumo: Os fungos dimórficos, Paracoccidioides brasiliensis (espécies cripticas S1, PS2, PS3) e Paracoccidioides lutzii (Pb01-like espécies), são agentes da paracoccidioidomicose (PCM), doença granulomatosa crônica, endêmica na América Latina, principalmente no Brasil. A doença apresenta grande variedade de manifestações clínicas, desde formas localizadas até disseminadas evoluindo para letalidade. O fungo tem capacidade de aderir, invadir e extravasar barreiras impostas pelos tecidos do hospedeiro. P. brasiliensis (Pb18) já foi observado tanto no interior de macrófagos, como no interior de células epiteliais in vivo e in vitro. A identificação do mecanismo pelo qual este fungo sobrevive no interior da célula hospedeira é campo fértil para a descoberta de sua patogênese, já que este microrganismo possui a capacidade de induzir sua própria endocitose em células epiteliais e muito provavelmente em macrófagos. A absorção de micronutrientes pelo fungo apresenta papel singular, tanto para sua nutrição e processo invasivo, como para sua sobrevivência no interior da célula hospedeira. A via endocítica em microrganismos é de fundamental importância na regulação de todo esse processo. O objetivo deste estudo foi avaliar a via endocítica de Pb18 e também de macrófagos infectados com este fungo. A avaliação da via endocítica de Pb18 foi realizada na condição de depleção de metais, onde foram analisados os genes Clatrina e Ypt7 (Homólogo de Rab7) por RT-PCR semi-quantitativo e PCR em tempo real (RT-PCR quantitativo). Também foi analisada a infecção de macrófagos por Pb18 cultivado na depleção de metais e em diferentes tensões de oxigênio. A via endocítica de macrófagos foi analisada por RT-PCR quantitativo e imunofluorescência. Esta análise foi realizada quando o fungo foi cultivado em... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The dimorphic fungus, Paracoccidioides brasiliensis (cryptic species S1, PS2, PS3) and Paracoccidioides lutzii (Pb01-like species), are agents of paracoccidioidomycosis (PCM), chronic granulomatous disease, endemic in Latin America, especially in Brazil. The disease has a wide variety of clinical manifestations, from localized forms to disseminated evolving to lethality. The fungus is able to adhere, invade and spill barriers imposed by host tissues. P. brasiliensis (Pb18) has already been observed both within macrophages, but also inside of epithelial cells in vivo and in vitro. Identification of the mechanism by which this fungus survive within the host cell is a fertile field for the discovery of their pathogenesis, since this microorganism has the ability to induce its own endocytosis in epithelial cells and most probably in macrophages. The micronutrient uptake by the fungus presents unique role, both for its nutritional and invasive procedure, such as for survival within the host cell. The endocytic pathway in microorganisms is of fundamental importance in the regulation of this process. The aim of this study was to evaluate the endocytic pathway of Pb18 and also macrophages infected with this fungus. The evaluation of the endocytic pathway of Pb18 was performed under the condition that depletion of metals, where the genes were analyzed Clathrin and Ypt7 (Rab7 homolog) by RT-PCR semi-quantitative and real-time PCR (RT-PCR quantitative). Was also analyzed by Pb18 infection of macrophages cultured in the depletion of metals at different oxygen tensions. The endocytic pathway of macrophages was analyzed by quantitative RT-PCR and immunofluorescence. This analysis was performed when the fungus was grown at different oxygen tensions and macrophages were infected with this and when the infection was incubated at... (Complete abstract click electronic access below)
Doutor
50
Crump, Larry T. "A mycological survey of commercial whirlpools in Delaware and Madison counties, Indiana". Virtual Press, 1989. http://liblink.bsu.edu/uhtbin/catkey/720283.
Testo completoAbstract (sommario):
Thirty-seven samples were taken from the water, step access and air/water interface surfaces of 10 commercial whirlpools in Delaware and Madison Counties, Indiana between September and March of 1986-1988. Dermatophytes were isolated from 19 of the samples, representing 51%. At least three species of the yeast genus Candid. were isolated from 13 (35%) of these samples. Fifty-eight percent of all dermatophytes isolated were found in male-only whirlpools, as were nearly 62% of all Candida species. Isolated dermatophytes included Trichophyton rubrum, T. menta,grophytes, T. tonsurans, T. verrucosum, Epidermophyton floccosum, Microsporum nanum, and one Trichophvton species. Whirlpools were grouped based on similarity of fungi isolated from each facility. Male whirlpools sorted into one group, except for one that clustered with female facilities. Coliform bacteria were found in 43% of all samples, and blue-green fluorescent pseudomonads were found in 54% of all samples. Most dermatophytes were isolated from the step access surface of the facilities tested, and more Candida species were isolated from the water than from either surface tested.Department of Biology