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Auswahl der wissenschaftlichen Literatur zum Thema „Hevea brasiliensis latex“
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Zeitschriftenartikel zum Thema "Hevea brasiliensis latex"
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Bourrain, JL. „Hevea brasiliensis Rather Than Latex“. Journal of Investigational Allergology and Clinical Immunology 26, Nr. 4 (30.07.2016): 278. http://dx.doi.org/10.18176/jiaci.0067.
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Glushakova, A. M., A. V. Kachalkin, I. A. Maksimova und I. Yu Chernov. „Yeasts in Hevea brasiliensis latex“. Microbiology 85, Nr. 4 (Juli 2016): 488–92. http://dx.doi.org/10.1134/s002626171604007x.
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Liengprayoon, Siriluck, Klanarong Sriroth, Eric Dubreucq und Laurent Vaysse. „Glycolipid composition of Hevea brasiliensis latex“. Phytochemistry 72, Nr. 14-15 (Oktober 2011): 1902–13. http://dx.doi.org/10.1016/j.phytochem.2011.04.023.
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HUANRALUEK, NARUEMON, CHAYANARD PHUKHAMSAKDA, CHANOKNED SENWANNA, SINANG HONGSANAN, RUVISHIKA S. JAYAWARDENA, DARBHE J. BHAT und KEVIN D. HYDE. „Verruconis heveae, a novel species from Hevea brasiliensis in Thailand“. Phytotaxa 403, Nr. 1 (09.05.2019): 47. http://dx.doi.org/10.11646/phytotaxa.403.1.4.
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Verruconis heveae, a new species accommodated in Sympoventuriaceae was isolated from dried latex on bark of a rubber tree (Hevea brasiliensis) collected from Phayao Province, Thailand. The comparison of its morphological characters distinguished V. heveae from other Verruconis species by having brown, woolly mycelium on the natural substrate and solitary, ellipsoidal to subglobose, 1–3 septate conidia. Phylogenetic analysis of a combined LSU and ITS dataset revealed a distinct lineage within Sympoventuriaceae.
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Lynam, Joan G., Holden T. Zugger und Elizabeth T. Amedee. „Ionic Liquids Separating Rubber Latex from Guayule“. Materials 14, Nr. 15 (30.07.2021): 4255. http://dx.doi.org/10.3390/ma14154255.
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Danger to rubber trees (Hevea brasiliensis) from South American leaf blight fungus imperils the world’s source of natural latex for essential rubber products. Avoiding latex allergies also requires a non-Hevea latex source. The present methods for removing latex entrapped in the individual cells of guayule plants require environmentally hazardous chemicals. This study proposes a new method for latex extraction from guayule using various ionic liquids (ILs) to dissolve cell walls and release latex, as substantiated by Fourier transform infrared spectroscopy (FTIR) data.
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Cardona, R., und J. Sánchez. „Reply to “Hevea brasiliensis Rather Than Latex”“. Journal of Investigational Allergology and Clinical Immunology 26, Nr. 4 (30.07.2016): 278. http://dx.doi.org/10.18176/jiaci.0071.
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Akasawa, Akira, Li-Shan Hsieh und Yuan Lin. „Serum reactivities to latex proteins (Hevea brasiliensis)“. Journal of Allergy and Clinical Immunology 95, Nr. 6 (Juni 1995): 1196–205. http://dx.doi.org/10.1016/s0091-6749(95)70076-5.
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Tao, Jinlong, Dongning He, Bin Tang, Lingxue Kong, Yongyue Luo, Pengfei Zhao, Wei Gong und Zheng Peng. „In situ synthesis of natural rubber latex-supported gold nanoparticles for flexible SERS substrates“. RSC Advances 5, Nr. 61 (2015): 49168–74. http://dx.doi.org/10.1039/c5ra05681k.
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Wang, Xue, Wen-Cheng Liu, Xue-Wei Zeng, Sa Yan, Yi-Min Qiu, Jin-Bo Wang, Xi Huang und Hong-Mei Yuan. „HbSnRK2.6 Functions in ABA-Regulated Cold Stress Response by Promoting HbICE2 Transcriptional Activity in Hevea brasiliensis“. International Journal of Molecular Sciences 22, Nr. 23 (24.11.2021): 12707. http://dx.doi.org/10.3390/ijms222312707.
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Low temperature remarkably limits rubber tree (Hevea brasiliensis Muell. Arg.) growth, latex production, and geographical distribution, but the underlying mechanisms of Hevea brasiliensis cold stress response remain elusive. Here, we identified HbSnRK2.6 as a key component in ABA signaling functions in phytohormone abscisic acid (ABA)-regulated cold stress response in Hevea brasiliensis. Exogenous application of ABA enhances Hevea brasiliensis cold tolerance. Cold-regulated (COR) genes in the CBF pathway are upregulated by ABA. Transcript levels of all five HbSnRK2.6 members are significantly induced by cold, while HbSnRK2.6A, HbSnRK2.6B, and HbSnRK2.6C can be further activated by ABA under cold conditions. Additionally, HbSnRK2.6s are localized in the cytoplasm and nucleus, and can physically interact with HbICE2, a crucial positive regulator in the cold signaling pathway. Overexpression of HbSnRK2.6A or HbSnRK2.6B in Arabidopsis extensively enhances plant responses to ABA and expression of COR genes, leading to increased cold stress tolerance. Furthermore, HbSnRK2.6A and HbSnRK2.6B can promote transcriptional activity of HbICE2, thus, increasing the expression of HbCBF1. Taken together, we demonstrate that HbSnRK2.6s are involved in ABA-regulated cold stress response in Hevea brasiliensis by regulating transcriptional activity of HbICE2.
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Yun, Yang, Zhang Zhi-Li, Liu Kuan-Can, Li Wei-Guo und Su Huo-Sheng. „Cloning and characteristics of a novel gene HbUEP from latex in Hevea brasiliensis“. Chinese Journal of Agricultural Biotechnology 5, Nr. 2 (August 2008): 165–68. http://dx.doi.org/10.1017/s1479236208002337.
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AbstractHbUEP, an ubiquitin extension protein gene from latex of the rubber tree (Hevea brasiliensis) was cloned and sequenced using a differentially ethphon-induced expressed cDNA subtraction library. The cDNA had 771 bp nucleotides, comprising a 226 bp 3′ untranslated region (UTR), 77 bp 5′UTR and a 468 bp open reading frame encoding a 156 amino acid peptide. Southern blotting analysis showed that this gene was a low copy number gene in the H. brasiliensis genome. Within 24 h after application of ethphon, the gene was expressed weakly in both control and latex sampled at 6 h, and strongly in latex sampled at 12 h, showing that this gene expression could be regulated by ethphon. Ethphon could increase the latex yield in H. brasiliensis. It is suggested that the HbUEP gene may be involved in the regulation of ethphon-induced high latex yield in H. brasiliensis.
Dissertationen zum Thema "Hevea brasiliensis latex"
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CAURET, LAUREN. „Nouveaux stimulants pour la production de latex par l'hevea brasiliensis“. Le Mans, 1995. http://www.theses.fr/1995LEMA1017.
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Intapun, Jutharat. „Study of the effects of biological maturation of coagula of hevea brasiliensis latex on dry rubber properties“. Montpellier SupAgro, 2009. http://www.theses.fr/2009NSAM0036.
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The aim of this work was to study the maturation phenomena undergone bycup coagula of Hevea brasiliensis latex. The experimental strategy was to firstcharacterize the maturation industrial conditions (temperature, relative humidity andoxygen content of the air), secondly to reproduce this maturation at laboratory scale inorder to, thirdly, be able to study the effect of key determinants such as microbialpopulation or enzymatic activity on processed natural rubber properties. The maturation conditions of cup rubber coagula stored as a pile in anindustrial plant have been characterized. This requested an optimization of theexperimental material used to measure conditions in order to get repeatable andconsistent data. It was found that temperature and relative humidity of the airincreased with depth within the pile. In contrast, oxygen content of the air within thepile decreased as depth increased. Effects of 24-day maturation in these conditions onrubber properties (pH, P0, PRI and Weight-average molar mass) were found to varywith the position of cup coagula within the pile. In order to be able to study maturation of coagula in laboratory controlledcondition, methodological and technical developments were performed and concernedthe design and optimization of a maturation device as well as of a dry rubber process(creping + drying). Before the development of devices, it was checked that thereduction of cup coagula size for practical experimental reasons would not induce anyartifact. The developed maturation device in laboratory was set up with 6 maturationunits, each of them being able to contain up to 18 mini-cup coagula. An assessment ofthe regulation of the maturation unit atmosphere showed that the developed deviceallowed the control of conditions in the following ranges: relative humidity10% - 90%, temperature 35°C - 45°C and oxygen content 0%-21%. Referring to thestudy of the conditions in cup coagula pile, it was decided to work at 40°C±1°C and90%±10% RH in the maturation device. The laboratory process parameters wereoptimized in order to obtain a rubber with the same quality as if it was processed infactory practice. In order to assess the involvement of microorganisms in the initial stage ofmaturation of natural rubber cup coagula, the inoculated rubber was characterized forits physical and structural properties for different maturation times. The resultsshowed that the quantity of microorganisms significantly affected the physicalproperties and molecular structure (Average-molar mass and gel content) of processedrubber. Microorganisms are not only involved in the increase of sensitivity to thermooxidationbut also in the crosslinking phenomenon between polyisoprene chains. Thetotal number of microorganisms in the inoculum was around 1x109 CFU/mL, amongwhich were yeasts, gram positive, gram negative and lactic acid bacteria. Fifteen ofthe 16 bacterial strains isolated from the inoculum used in latex treatments producedhydrolytic enzymes such as lipase, phospholipase and protease when inoculated inspecific media, thus potentially participating to lipid and protein degradation in latexand coagula. The addition of lipase in mini-cup coagula resulted in an increasedrelease of free fatty acids but had no significant effect on PRI evolution during thefirst 6 days of maturation. The main effect was observed in the presence of a protease,papain, which showed a clear positive dose-effect on enzyme concentration on P0. This enzyme also had an improving effect on PRI. The methodologies and devices developed during this study should serve as abasis for further studies aiming at a better understanding of the role ofmicroorganisms and enzymes in the variability of quality of natural rubberL'objectif de ce travail était d'étudier le phénomène de maturation des coagula de latex d'Hevea brasiliensis. La stratégie expérimentale a consisté dans un premier temps à caractériser les conditions de maturations régnant sur un site industriel (température,humidité relative, teneur en oxygène de l'air), puis de reproduire ces conditions de maturation à l'échelle du laboratoire dans le but de pouvoir, dans une troisième phase, étudier l'effet de paramètres clés tels que la population microbienne ou l'activité de diverses enzymes sur les propriétés du caoutchouc naturel obtenu à partir de ces coagula. Les conditions de maturation des coagula de latex empilés sur un site industriel ont été caractérisées. Ceci a nécessité la mise au point d'un matériel expérimental spécifique permettant des mesures fiables et répétables. Nous avons montré que la température et l'humidité relative de l'air au sein du tas augmentent avec la profondeur, alors que la teneur en oxygène diminue jusqu'à des conditions d'anaérobiose. Après 24 jours de maturation dans ces conditions, les propriétés des coagula (pH) et du caoutchouc obtenu (P0, PRI, masse moléculaire moyenne) dépendent de la position des coagula au sein de la pile. L'étude de la maturation des coagula dans des conditions de laboratoire contrôlées a nécessité des développements méthodologiques et techniques aboutissant à la mise en place et à l'optimisation d'un dispositif de maturation contrôlée associé à un procédé miniaturisé de production de caoutchouc sec comprenant une étape de crêpage et un séchage au four. Ce dispositif a été confronté au système réel en vérifiant que la réduction d'échelle n'introduisait pas de biais dans les propriétés des produits étudiés. Le dispositif de maturation contrôlée est constitué de 6 unités pouvant fonctionner en parallèle, chacune d'entre elle pouvant contenir jusqu’à 18 échantillons. Les unités sont contrôlées en humidité relative (10%-90%), température (35Ê C - 45Ê C) et teneur en oxygène (0-21%). Sur la base des mesures réalisées sur site industriel, les études on été réalisées à 40Ê CØ+1Ê C et 90%Ø+10% d'humidité relative dans le dispositif de maturation. Nous avons ensuite démontré le rôle des microorganismes dans la maturation des coagula de latex et leur impact sur les propriétés du caoutchouc naturel sec en comparant les propriétés physiques et structurales, avant et après maturation, d'échantillons de caoutchouc issus de coagula inoculés avec des quantités variables de microorganismes provenant d'un coagulum industriel. Cette étude a mis en évidence un effet-dose des microorganismes sur ces propriétés. Les microorganismes contenus dans l'inoculum comprenaient des levures et des bactéries gram positives et gram négatives, dont des bactéries lactiques. Quinze des seize souches isolées produisaient des enzymes hydrolytiques, notamment à activité lipase, phospholipase et protéase, qui pourraient participer à la dégradation de lipides et protéines au sein du latex et des coagula. L'addition de lipase pure à des coagula dans lesquels le développement des microorganismes était inhibé a provoqué la libération d'acides gras sans toutefois modifier les propriétés du caoutchouc après 6 jours de maturation. Par contre, l'addition de papaÉine a provoqué une amélioration de la valeur de la viscosité initiale (P0) des échantillons directement liée à la quantité d'enzyme ajoutée. L'activité de cette protéase a également entraîné une augmentation de la résistance à la thermooxydation (PRI) du caoutchouc. Les méthodologies et outils développés au cours de se travail devraient permettre le développement de futures recherches visant à comprendre le rôle des microorganismes et des enzymes dans la variabilité de la qualité du caoutchouc naturel
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Gomes, Willian Pereira. „Prevulcanização do látex natural extraído da "hancornia speciosa gomes" (Mangabeira) e da "hevea brasiliensis" (seringueira) /“. Ilha Solteira, 2013. http://hdl.handle.net/11449/136022.
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Orientador: José Antonio MalmongeBanca: Rosangela da Silva de Lauretiz
Banca: Rogério Manoel Biagi Moreno
Resumo: A borracha natural é um dos polímeros mais consumidos mundialmente, onde seu principal mercado é o setor pneumático com cerca de três quartos do consumo total. A seringueira é a mais importante produtora de borracha natural, sendo responsável por cerca de 99% da produção mundial A mangabeira é também uma arvore lactescente produzida quase em sua totalidade de forma extrativista e visada somente para a produção do seu fruto, a mangaba. Embora já ter sido utilizada comercialmente em períodos emergenciais, hoje a borracha natural provinda da mangabeira não tem qualquer utilização tecnológica, pois é considerada uma borracha de qualidade inferior. Neste trabalho foram produzidos filmes de borracha prevulcanizada com o látex de seringueira, de mangabeira e também com a mistura (m/m) do látex de mangabeira no látex de seringueira, nas proporções de 95/5, 90/10, 80/20, 70/30 e 60/40. Os resultados mostraram que o número de ligações cruzadas, tensão na ruptura e dureza Shore A são dependentes do sistema de vulcanização convencional, semi-eficiente ou eficiente, e da temperatura e do tempo de cozimento do latex de ambas as fontes. Os valores dessas propriedades encontrados para a borracha da mangabeira foram inferiores ao da borracha da seringueira. O maior valor de tensão de ruptura, dureza Shore e deformação encontrada para a borracha de seringueira foi alcançado utilizando o sistema convencional com 3 horas de cozimento sob 80°C. Esses valores são: 22 MPa, 42 Shore A e 895% o que é aproximadamente 150%, 68% e 25%, respectivamente, maiores do que os maiores valores encontrados para a borracha da mangabeira (8,8 MPa, 25 Shore A e 714%) que foi obtido utilizando o sistema semi-eficiente. As borrachas obtidas da mistura dos látex apresentaram, para composições inferiores a 20%, em massa de borracha de mangabeira, um comportamento similar a da seringueira mostrando ser viável a sua utilização para fabricação...
Abstract: Natural rubber is one of the most consumed polymer in the worldwide and pneumatic industry is responsible for approximately three fourths of total consumption. Hevea brasiliensis is the most important producer of natural rubber, being responsible for 99% of global production. The Hancornia speciosa Gomes is also produces white latex that can be tapped from the tree similarly to Hevea. Although it has been used commercially in emergency periods, nowadays Hancornia rubber has no technology use due to its low production and rubber quality. The latex blend can be a viable alternative to the use of mangabeira latex as one additional income besides of fruit commercialization. In this sense, the proposal of this work was to evaluate the influence of prevulcanization condition in the Hancornia speciosa Gomes (mangabeira) and Hevea brasiliensis (seringueira) latexes and also in its mixture, on the rubber proprieties. The latexes were prevulcanizated by conventional (CV), semi-efficient (SEV) and efficient (EV) vulcanization systems under temperatures of 60, 70 and 80 ° C. The crosslinked quantity was investigated by the swelling technique and the mechanical proprieties were obtained from tensile experiments and shore A hardness. The results showed that the quantity of crosslinked, stress at break and shore hardness are dependent of prevulcanization condition. The values of these proprieties found for mangabeira rubber were lower than the values found for the seringueira rubber. The highest stress at break, shore hardness and strain to seringueira and mangabeira rubber were obtained using the CV and SEV systems, respectively, under temperature of 80° C for 3 hours. Theses value are: 22 MPa, 42 shore A and 895% that are around 150%, 68% e 25%, respectively, higher than found to mangabeira rubber (8,8 MPa, 25 Shore A and 714%). The rubbers obtained from mixture of latex have the mechanical proprieties closed to the seringueira rubber for blends ...
Mestre
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Bahari, Azlina. „Approaches to understanding diversity in rubber and carotenoid synthesis in Hevea brasiliensis latex“. Thesis, University of Dundee, 2019. https://discovery.dundee.ac.uk/en/studentTheses/73b6fffb-faf0-4fb9-94f1-aa9bbb330154.
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Hevea brasiliensis latex contains a large quantity of high molecular weight rubber and is thus the primary commercial source of natural rubber. Rubber and other non-rubber isoprenoids in Hevea latex are synthesised from isopentenyl diphosphate (IPP) generated from the cytoplasmic mevalonate (MVA) pathway and the plastidic methyl erythritol phosphate pathway (MEP). This study utilised two rubber tree clones (RRIM600 and PB235) that show visibly contrasting levels of yellow carotenoids for the measurement of latex isoprenoids (carotenoids, rubber and isoprenoid intermediates) and transcript levels of the genes involved in isoprenoid biosynthesis. Metabolite extraction and analysis showed that four major carotenoids namely lutein, zeaxanthin, α-carotene and β-carotene were consistently present in both RRIM600 and PB235 latex. β-carotene was found to be the major carotenoid, at 1.2 μg/g in PB235 and 0.8 μg/g in RRIM600 fresh latex samples. However, the analytical method developed to measure isoprenoid intermediates needed to be further optimised to increase extraction efficiency. To enable accurate measurement of transcript levels of key genes involved in the isoprenoid biosynthetic pathway, a set of reference transcripts was constructed by merging short-reads (RNA-seq) and long-reads (Iso-seq and full-length cDNA sequences) data from Hevea brasiliensis. This produced a comprehensive set of 193,997 transcript sequences with good level of coverage of predicted transcripts and highly conserved core plant genes. Not only did the reference transcriptome update the annotation of rubber gene models, additional transcript variants were also discovered. Manual curation of gene models for key steps associated with rubber and carotenoids resulted in a repertoire of 115 genes, with 151 corresponding transcript variants. Subsequently, differential expression analysis on the basis of mapping RRIM600 and PB235 RNA-seq reads to the reference transcriptome revealed isoform-specific expression of genes for biosynthesis of carotenoids (PSY isoform 2), IPP (AACT2 and HMGR1) and rubber (REFSRPP gene members). In addition, the levels of these genes correlated positively with the carotenoid and rubber content measurements from the same latex of PB235 and RRIM600 used for metabolite extraction. Finally, the utility of the reference transcript catalogue was demonstrated by the characterisation of the REFSRPP gene family, which is involved in rubber elongation steps. REFSRPP gene family showed a local expansion which appear to be unique to Hevea. A pilot study has demonstrated there is considerable diversity of the genomic region containing the duplicated REFSRPP genes.
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Piyatrakul, Piyanuch. „Caractérisation des gènes AP2/ERF impliqués dans le développement chez Hevea brasiliensis“. Thesis, Montpellier, SupAgro, 2013. http://www.theses.fr/2013NSAM0033/document.
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Hevea brasiliensis est une culture industrielle majeure pour la production de caoutchouc naturel (CN). La stimulation par l'éthéphon, un libérateur d'éthylène, est utilisée pour augmenter la production de latex en prolongeant son écoulement et en stimulant le métabolisme pour la régénération du latex. Cependant, le mécanisme d'action de l'éthylène n'est pas clairement élucidé chez l'hévéa. L'éthylène est un signal important qui régule le développement des plantes. Les facteurs de transcription AP2/ERF, et plus particulièrement les Ethylene Response Factors, jouent un rôle crucial dans le développement et la réponse aux stress biotiques et abiotiques chez les plantes. La production d'éthylène et sa signalisation sont aussi importantes en embryogenèse somatique et tout spécialement chez les espèces récalcitrantes à la culture in vitro.Dans cette étude, le transcriptome de référence a été amélioré par addition des fragments de séquence d'ARN issus de tissus reproducteurs lors d'un nouvel assemblage. Les 30.342 contigs ont été annotés par la base de données Gene Ontology. L'analyse des facteurs de transcription a permis d'identifier 2.448 contigs qui ont été classés en 58 familles de facteurs de transcription. Six pourcents de ces facteurs de transcription correspondent aux membres de la superfamille des AP2/ERF. L'accumulation de transcrits des gènes AP2/ERF a été analysée au cours du processus d'embryogenèse somatique chez des lignées de cal avec différents potentiels de régénération et dans différents tissus végétatifs et reproducteurs. L'analyse de l'abondance relative de transcrits dans les différents tissus montre que les ERFs des groupes I, VII et VIII sont fortement présents à tous les stades de l'embryogenèse somatique et dans les tissus immatures et matures de fleurs males et femelle, d'embryons zygotiques, de feuilles, d'écorce et de latex. Quarante gènes AP2/ERF représentent des marqueurs d'expression génique pour le potentiel de régénération de plantes de lignées de cal à différents stades du processus d'embryogenèse somatique. Quatorze marqueurs d'expression génique permettent même de prédire la capacité de régénération dès le stade de multiplication du cal. Cinquante-neuf marqueurs d'expression géniques sont spécifiquement exprimés dans les différents tissus de l'hévéa, et plusieurs AP2/ERFs ont les transcrits fortement accumulés dans le latex. La plupart des marqueurs de l'expression génique du latex appartient aux ERF du groupe VII. Les ERFs de ce groupe ont un motif conservé en N-terminal (MCGGAII), lequel est impliqué dans la voie N-end rule. Les analyses de localisation subcellulaire et de transactivation suggèrent que ces gènes HbERF-VII codent pour des facteurs de transcription fonctionnels potentiellement impliqués dans la réponse à l'hypoxie dans le latexHevea brasiliensis is the major industrial crop for natural rubber (NR) production. Ethephon stimulation, an ethylene releaser, is used for increasing latex production by prolonging latex flow and stimulating the metabolism required for the latex regeneration. However, the mechanism of ethylene action is not clearly elucidated in this species. Ethylene is an important signal regulating the plant development. AP2/ERF transcription factors, and especially Ethylene-Response Factors, play a crucial role in plant development and response to biotic and abiotic stresses. Ethylene production and signalling are also important to somatic embryogenesis, especially for species that are recalcitrant in in vitro culture.In this study, a comprehensive Hevea transcriptome was improved using additional RNA reads from reproductive tissues in a new assembly. The 30,342 contigs were annotated in the Gene Ontology database. The analysis of transcription factors led to 2,448 contigs being identified, which were classed in 58 transcription factor families. Six percent of the transcription factors corresponded to members from the AP2/ERF superfamily. The transcript accumulation of AP2/ERF genes was analyzed during somatic embryogenesis for callus lines with different regeneration potential and in various vegetative and reproductive tissue of Hevea. The relative transcript abundance were studied and showed that ERFs from group I, VII and VIII were abundant at all stages of the somatic embryogenesis as well as, in both immature and mature male and female flowers, zygotic embryos, leaf, bark and latex. Forty genes were identified as expression marker for callus with different plant regeneration potential regeneration capacity. Interestingly, fourteen expression marker genes were found that be able to predict the regeneration capacity of callus at proliferating calli, the early stage of somatic embryogenesis process. Fifty-nine expression marker genes were found in the various plant tissues. Several AP2/ERF genes were shown highly transcript accumulation in latex and were assigned as latex expression marker genes. Almost of latex expression marker genes belong to the ERF group VII. Base on conserved motif analysis showed this ERF group contained the conserved N-terminal motif (MCGGAII) involved in the N-end rule pathway. Subcellular localization and transactivation analyses suggested that HbERF-VII candidate genes encoded functional transcription factors
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Carlos, Bruna Leonel. „Efeitos da membrana de látex na regeneração de defeito ósseo em tíbia de rato“. Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/17/17142/tde-02042018-112204/.
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Problemas de consolidação óssea são um grande desafio clínico, pois geram altos custos de tratamento, morbidades e prejuízos a qualidade de vida. A técnica de regeneração óssea guiada é empregada com o intuito de promover a melhora no processo de regeneração de defeitos ósseos através da utilização de barreiras biológicas, que protegem o local da lesão e favorecem a ação de células osteogênicas. A membrana de látex natural, extraído da seringueira Hevea brasiliensis tem sido apontado como um biomaterial promotor da regeneração em diferentes tecidos, e por este motivo escolhido como objeto de estudo desta pesquisa. O objetivo foi avaliar o efeito da utilização de membrana de látex natural no processo de regeneração guiada de defeito ósseo em ossos longos de ratos, através de análises estruturais, radiológicas, microscópicas e da expressão de proteínas osteogênicas. Foram utilizados sessenta ratos Wistar divididos igualmente em quatro grupos (n=15), sendo: animais tratados com membrana de látex por uma (L1) ou quatro semanas (L4) e animais que não receberam tratamento específico por uma (C1) ou quatro semanas (C4). Um defeito ósseo de 2,5 mm de diâmetro foi realizado na região medial da tíbia esquerda de cada animal. Nos animais do grupo tratado, uma membrana de látex foi posicionada sobre os defeitos ósseos. Após os períodos experimentais de uma ou quatro semanas os animais foram submetidos a eutanásia e a tíbia esquerda de cada animal foi dissecada, limpa das partes moles e submetida às análises macroscópica, densitométrica, radiológica, mecânica, histomorfométrica, estereológica e imunohistoquímica. A influência das varáveis tempo e membrana, bem como a interação tempo*membrana sobre os dados foram avaliadas. Para os dados referentes à imunomarcação de osteocalcina foi aplicado teste de modelo linear generalizado com fatores independentes. Para o restante dos resultados foi realizada análise de ANOVA multivariada com dois fatores independentes. Todas as comparações foram realizadas com ajuste de Bonferroni e adotado nível de significância de 5%. Foram observadas diferenças estatisticamente significantes em relação a variável tempo, em que grupos avaliados quatro semanas após a cirurgia apresentaram resultados superiores para as medidas de comprimento (p<0,001), massa (p<0,001), força máxima (p<0,001) e rigidez relativa da tíbia (p<0,001), bem como para as medidas de densidade radiológica (p=0,008), densidade mineral óssea (p=0,017), volume ósseo neoformado (p<0,001) e fibras de colágeno tipo III (p<0,001). Em relação à utilização da membrana de látex, os grupos tratados apresentaram resultados estatisticamente superiores para as análises de rigidez relativa (p=0,048), fibras de colágeno tipo I (p=0,018), volume ósseo neoformado (p<0,001) e expressão de osteopontina (p=0,037). Concluímos que a utilização de membrana de látex em regeneração óssea guiada em defeitos realizados em tíbias de ratos melhorou sensivelmente a regeneração do tecido.Problems of bone consolidation are a significant clinical challenge, as they generate high treatment costs, morbidities, and damages to the quality of life. The guided bone regeneration technique is used to improve the regeneration process of bone defects through the use of biological barriers that protect the site and favor the action of osteogenic cells. The natural latex membrane extracted from the rubber tree Hevea brasiliensis has been identified as a biomaterial promoting regeneration in different tissues, and for this reason chosen as the object of study of this research. The objective was to evaluate the effect of the use of natural latex membrane in the process of guided regeneration of bone defect in long bones of rats, through structural, radiological, microscopic analysis and the expression of osteogenic proteins. Sixty Wistar rats were equally divided into four groups (n = 15): latex membrane treated animals for one (L1) or four weeks (L4) and animals that received no specific treatment for one (C1) or four weeks (C4). A bone defect of 2.5 mm diameter was performed in the medial region of the left tibia of each animal. In the animals of the treated group, a latex membrane was positioned over the bone defects. After the experimental periods of one or four weeks, the animals were submitted to euthanasia, and the left tibia of each animal was dissected, cleaned of soft parts and submitted to macroscopic, densitometric, radiological, mechanical, histomorphometric, stereological and immunohistochemical analysis. The influence of the variable time and membrane as well as the time * membrane interaction on the data were evaluated. For the data referring to the osteocalcin immunostaining, a generalized linear model with independent factors was applied. For the rest of the results, a multivariate ANOVA analysis was performed with two independent factors. All comparisons were performed with Bonferroni adjustment and adopted a significance level of 5%. Statistically significant differences were observed in relation to the time variable, in which groups evaluated four weeks after surgery presented superior results for the measures of length (p <0.001), mass (p <0.001), maximal strength (p <0.001) and stiffness (P <0.001), as well as for measurements of radiological density (p = 0.008), bone mineral density (p = 0.017), neoformed bone volume (p <0.001) and type III collagen fibers (p <0.001) ). About the use of the latex membrane, the treated groups presented statistically superior results for analyzes of relative stiffness (p = 0.048), type I collagen fibers (p = 0.018), neoformed bone volume (p <0.001) and expression of Osteopontin (p = 0.037). We conclude that the use of latex membrane in guided bone regeneration in defects performed in rat tibiae significantly improved tissue regeneration.
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Gomes, Willian Pereira [UNESP]. „Prevulcanização do látex natural extraído da hancornia speciosa gomes (Mangabeira) e da hevea brasiliensis (seringueira)“. Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/136022.
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000858512.pdf: 2016296 bytes, checksum: 1e82db6903bf61cb290beaca684ff652 (MD5)A borracha natural é um dos polímeros mais consumidos mundialmente, onde seu principal mercado é o setor pneumático com cerca de três quartos do consumo total. A seringueira é a mais importante produtora de borracha natural, sendo responsável por cerca de 99% da produção mundial A mangabeira é também uma arvore lactescente produzida quase em sua totalidade de forma extrativista e visada somente para a produção do seu fruto, a mangaba. Embora já ter sido utilizada comercialmente em períodos emergenciais, hoje a borracha natural provinda da mangabeira não tem qualquer utilização tecnológica, pois é considerada uma borracha de qualidade inferior. Neste trabalho foram produzidos filmes de borracha prevulcanizada com o látex de seringueira, de mangabeira e também com a mistura (m/m) do látex de mangabeira no látex de seringueira, nas proporções de 95/5, 90/10, 80/20, 70/30 e 60/40. Os resultados mostraram que o número de ligações cruzadas, tensão na ruptura e dureza Shore A são dependentes do sistema de vulcanização convencional, semi-eficiente ou eficiente, e da temperatura e do tempo de cozimento do latex de ambas as fontes. Os valores dessas propriedades encontrados para a borracha da mangabeira foram inferiores ao da borracha da seringueira. O maior valor de tensão de ruptura, dureza Shore e deformação encontrada para a borracha de seringueira foi alcançado utilizando o sistema convencional com 3 horas de cozimento sob 80°C. Esses valores são: 22 MPa, 42 Shore A e 895% o que é aproximadamente 150%, 68% e 25%, respectivamente, maiores do que os maiores valores encontrados para a borracha da mangabeira (8,8 MPa, 25 Shore A e 714%) que foi obtido utilizando o sistema semi-eficiente. As borrachas obtidas da mistura dos látex apresentaram, para composições inferiores a 20%, em massa de borracha de mangabeira, um comportamento similar a da seringueira mostrando ser viável a sua utilização para fabricação...
Natural rubber is one of the most consumed polymer in the worldwide and pneumatic industry is responsible for approximately three fourths of total consumption. Hevea brasiliensis is the most important producer of natural rubber, being responsible for 99% of global production. The Hancornia speciosa Gomes is also produces white latex that can be tapped from the tree similarly to Hevea. Although it has been used commercially in emergency periods, nowadays Hancornia rubber has no technology use due to its low production and rubber quality. The latex blend can be a viable alternative to the use of mangabeira latex as one additional income besides of fruit commercialization. In this sense, the proposal of this work was to evaluate the influence of prevulcanization condition in the Hancornia speciosa Gomes (mangabeira) and Hevea brasiliensis (seringueira) latexes and also in its mixture, on the rubber proprieties. The latexes were prevulcanizated by conventional (CV), semi-efficient (SEV) and efficient (EV) vulcanization systems under temperatures of 60, 70 and 80 ° C. The crosslinked quantity was investigated by the swelling technique and the mechanical proprieties were obtained from tensile experiments and shore A hardness. The results showed that the quantity of crosslinked, stress at break and shore hardness are dependent of prevulcanization condition. The values of these proprieties found for mangabeira rubber were lower than the values found for the seringueira rubber. The highest stress at break, shore hardness and strain to seringueira and mangabeira rubber were obtained using the CV and SEV systems, respectively, under temperature of 80° C for 3 hours. Theses value are: 22 MPa, 42 shore A and 895% that are around 150%, 68% e 25%, respectively, higher than found to mangabeira rubber (8,8 MPa, 25 Shore A and 714%). The rubbers obtained from mixture of latex have the mechanical proprieties closed to the seringueira rubber for blends ...
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Agostini, Deuber Lincon da Silva [UNESP]. „Estudo dos componentes não isoprênicos do látex de Hevea brasiliensis indutores de angiogênese“. Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/103766.
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agostini_dls_dr_bauru.pdf: 1803645 bytes, checksum: 1ba74c4c9393d0cd53d03478b6fe2f01 (MD5)Atualmente é comprovado o poder de indução de angiogênese e neoformação tecidual através de membranas de borracha natural de Hevea brasiliensis. Este trabalho apresenta um estudo sobre as propriedades e a caracterização das frações não isoprênicas, separadas por centrifugação do látex, utilizado como biomaterial na indução de angiogênese e de neoformação. As frações constituintes, F2 e F3 sem o tradicional agente estabilizante de hidroxido de amônio (NH4OH), foram liofilizadas para a redução da quantidade de água e estabilização, em seguida tratadas termicamente a temperatura de 40,60,80, 100, 120 e 140ºC e novamente liofilizadas, sendo caracterizada através das técnicas de Kjeldahl, Soxhlet, de espectroscopia de absorção no infravermelho (FT-IR), Ressonância Magnética Nuclear (RMn-13C). Difração de raios x (DRX), termogravimetria (TG) acoplado ao FT-IR (IG/FT-IR), calorimetria exploratória diferencial (DSC), eletroforese, dosagens de citocinas e síntese de óxido nítrico considerando o fator limitate do uso do látex como um material bioativo, que é a temperatura de tratamento térmico, realizado para a obtenção das membranas de borracha natural, em torno de 85ºC. Foi possível verificar que a fração F3 constituinte do látex, tem propriedades anti-inflamatórias e que a fração F2 possui propriedades pró-inflamatórias
Currently it is proven the hability of inducing angiogenesis and tissue neoformating through membranes of natural rubber Hevea brasiliensis, so this work presents a study on the properties and characterization of non-isoprene fractions, separated by centrifugation, the latex used as biomaterial for induction and neoformation of angiongenesis and lyophilized without the traditional stabilizing agent, ammonium hydroxide (NH4OH). The fractions constituents, F2 and F3 fractions were lyophilized without the traditional stabilizing agent, ammonium hydroxide (NH4OH). The fractions constituents, F2 and F3 fractions were lyophilized to reduce the amount of water and stabilization, and then heat treated at temperature of 40, 60, 80, 100, 120 and 140ºC bieng characterized by the techniques of kjeldahl, Soxhlet, of absorption spectroscopy infrared (FT-IR), Nuclear Magnetic Resonance (NMR-13C), X-ray Diffraction (XRD), thermogravimetry (TG) coupled to FT-IR (TG-IR), differential scanning calorimetry (DSC), electrosphoresis, serum cytokines and oxide nitric (NO) considering the limiting factor in the use of latex as a bioactive material, which is the thermal treatment temperature, held for obtaining membranes of natural rubber, about 85ºC. It was possible to verify that the fraction F3 constituent latex has anti-inflammatory and the fraction F2 take inflammatory properties
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Agostini, Deuber Lincon da Silva. „Estudo dos componentes não isoprênicos do látex de Hevea brasiliensis indutores de angiogênese /“. Bauru, 2013. http://hdl.handle.net/11449/103766.
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Orientador: Aldo Eloizo JobBanca: Mariselma Ferreira
Banca: Ivan Helmuth Bechtold
Banca: José Antonio Malmonge
Banca: Eduardo René Perez
Resumo: Atualmente é comprovado o poder de indução de angiogênese e neoformação tecidual através de membranas de borracha natural de Hevea brasiliensis. Este trabalho apresenta um estudo sobre as propriedades e a caracterização das frações não isoprênicas, separadas por centrifugação do látex, utilizado como biomaterial na indução de angiogênese e de neoformação. As frações constituintes, F2 e F3 sem o tradicional agente estabilizante de hidroxido de amônio (NH4OH), foram liofilizadas para a redução da quantidade de água e estabilização, em seguida tratadas termicamente a temperatura de 40,60,80, 100, 120 e 140ºC e novamente liofilizadas, sendo caracterizada através das técnicas de Kjeldahl, Soxhlet, de espectroscopia de absorção no infravermelho (FT-IR), Ressonância Magnética Nuclear (RMn-13C). Difração de raios x (DRX), termogravimetria (TG) acoplado ao FT-IR (IG/FT-IR), calorimetria exploratória diferencial (DSC), eletroforese, dosagens de citocinas e síntese de óxido nítrico considerando o fator limitate do uso do látex como um material bioativo, que é a temperatura de tratamento térmico, realizado para a obtenção das membranas de borracha natural, em torno de 85ºC. Foi possível verificar que a fração F3 constituinte do látex, tem propriedades anti-inflamatórias e que a fração F2 possui propriedades pró-inflamatórias
Abstract: Currently it is proven the hability of inducing angiogenesis and tissue neoformating through membranes of natural rubber Hevea brasiliensis, so this work presents a study on the properties and characterization of non-isoprene fractions, separated by centrifugation, the latex used as biomaterial for induction and neoformation of angiongenesis and lyophilized without the traditional stabilizing agent, ammonium hydroxide (NH4OH). The fractions constituents, F2 and F3 fractions were lyophilized without the traditional stabilizing agent, ammonium hydroxide (NH4OH). The fractions constituents, F2 and F3 fractions were lyophilized to reduce the amount of water and stabilization, and then heat treated at temperature of 40, 60, 80, 100, 120 and 140ºC bieng characterized by the techniques of kjeldahl, Soxhlet, of absorption spectroscopy infrared (FT-IR), Nuclear Magnetic Resonance (NMR-13C), X-ray Diffraction (XRD), thermogravimetry (TG) coupled to FT-IR (TG-IR), differential scanning calorimetry (DSC), electrosphoresis, serum cytokines and oxide nitric (NO) considering the limiting factor in the use of latex as a bioactive material, which is the thermal treatment temperature, held for obtaining membranes of natural rubber, about 85ºC. It was possible to verify that the fraction F3 constituent latex has anti-inflammatory and the fraction F2 take inflammatory properties
Doutor
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Yusof, Faridah. „Factors affecting the formation of rubber from isopentenyl pyrophosphate in Hevea brasiliensis latex“. Thesis, University of Hertfordshire, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361264.
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Kainth, Nisha Rani. The effects of storage on the proteins of commercial high ammonia Hevea brasiliensis latex with special reference to their potential allergenicity. Birmingham: University of Birmingham, 1999.
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George, Sherin, P. R. Suresh, P. A. Wahid, Ramesh B. Nair und K. I. Punnoose. „Active root distribution pattern of Hevea brasiliensis determined by radioassay of latex serum“. In Agroforestry for Commodity Production: Ecological and Social Dimensions, 11–17. Dordrecht: Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-90-481-3365-9_2.
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Pujade-Renaud, V., C. Perrot-Rechenman, J. D’auzac, J. L. Jacob und J. Guern. „Modulation of Gene Expression under Ethylene Treatment in the Latex of Hevea brasiliensis“. In Cellular and Molecular Aspects of the Plant Hormone Ethylene, 162–63. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-017-1003-9_38.
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Korieocha, J. N., O. N. Nwabueze und S. N. Anokwuru. „Morphological Characterization and Evaluation of Hevea brasiliensis for Genetic Diversity and Latex Quality Attributes“. In Proceedings of the 6th Biennial Conference of Organization for Women in Science for the Developing World Nigeria (OWSD Garden City 2023), 253–69. Dordrecht: Atlantis Press International BV, 2023. http://dx.doi.org/10.2991/978-94-6463-306-1_16.
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Nazhirah, M., und Y. Faridah. „Screening and Separation of Industrially Useful Hydrolases from the Wasteful Skim Latex Serum of Hevea Brasiliensis“. In Developments in Sustainable Chemical and Bioprocess Technology, 285–94. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-1-4614-6208-8_34.
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Ho, C. C. „CHAPTER 4. The Production of Natural Rubber from Hevea brasiliensis Latex: Colloidal Properties, Preservation, Purification and Processing“. In Polymer Chemistry Series, 73–106. Cambridge: Royal Society of Chemistry, 2013. http://dx.doi.org/10.1039/9781849737647-00073.
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Li, Dejun, Shaohua Wu und Longjun Dai. „Current Progress in Transcriptomics and Proteomics of Latex Physiology and Metabolism in the Hevea brasiliensis Rubber Tree“. In The Rubber Tree Genome, 117–35. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-42258-5_8.
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Chréstin, Hervé, Xavier Gidrol, Michel Péan und Bernard Marin. „$$\Delta {{\overline {\mu {\text{H}}} }^{{\text{ + }}}}$$ -Controlled Reversible Fluxes of H+ and Calcium at the Tonoplast but Quasi-Total Citrate Sequestration within the Intact Vacuoles from the Latex Cells of Hevea Brasiliensis. Implications in the Production of Natural Rubber“. In Plant Vacuoles, 325–38. Boston, MA: Springer US, 1987. http://dx.doi.org/10.1007/978-1-4684-5341-6_44.
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Aso, Michitake. „Civilizing Latex“. In Rubber and the Making of Vietnam, 23–56. University of North Carolina Press, 2018. http://dx.doi.org/10.5149/northcarolina/9781469637150.003.0002.
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Rubber trees motivated the utilization, and construction, of imperial and national networks of knowledge production that linked French Indochina to France and to other colonial territories around the world. This effect placed rubber at the heart of efforts to discipline the tropics. Chapter 1 examines the introduction of hevea brasiliensis to Indochinese environments during the late nineteenth and early twentieth centuries, a process that involved laws marking the physical and intellectual boundaries between forests and plantation agriculture. It begins with a discussion of the southeast region of Vietnam and the study of nature in Indochina during the nineteenth century. New understandings of human and nonhuman natures enabled the production of commodities such as rubber, and rubber production for global consumption in turn helped reformulate the coproduction of human and nonhuman natures in local places. The chapter lays down a baseline for evaluating later transformations in environment and health as plantation agriculture replaced biological diverse habitats with much simpler ecologies.
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d'Auzac, J., und J. L. Jacob. „The Composition of Latex from Hevea Brasiliensis as a Laticiferous Cytoplasm“. In Physiology of Rubber Tree Latex, 59–88. CRC Press, 2018. http://dx.doi.org/10.1201/9781351075695-4.
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Rafał Kędzia, Jacek, Anna Maria Sitko, Józef Tadeusz Haponiuk und Justyna Kucińska Lipka. „Natural Rubber Latex - Origin, Specification and Application“. In Application and Characterization of Rubber Materials [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.107985.
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The chapter contains information about the origin of natural rubber latex (NRL) (Hevea brasiliensis) and the processing of field latex, considering quality changes occurring during the preparation of raw materials for distribution. The main types of concentrated natural rubber latex are described. A specification of natural rubber latex (NRL) in terms of key parameters tested by manufacturers and customers is presented. Test methods for verifying if the material meets the requirements of ISO 2004 and internal specifications are described based on standards and commonly used techniques. The next subject touched in the chapter is prevulcanization as the processing of concentrated latex with a change of its properties. One of the main industrial applications of NRL as prevulcanized latex (PV) is the production of dipped goods like gloves or balloons. Currently, some trends and challenges relate to sustainability issues are presented (carbon footprint, FSC).