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排序方式: 共有967条查询结果,搜索用时 15 毫秒
911.
912.
Koffi Christophe Kobenan Kouadio Kra Norbert Bini Malanno Kouakou Ibrahime Sinan Kouadio Gokhan Zengin Germain Elisabeth Cynthia Ochou Nina Reine Kosso Boka Philippe Menozzi Ochou Germain Ochou Acka Emmanuel Dick 《化学与生物多样性》2021,18(11):e2100497
Among the alternatives to environmentally toxic and socio-economically unacceptable chemical pesticides, essential oils from Ocimum gratissimum and Cymbopogon citratus were tested on the main pests and beneficial insects of the cotton plant in Côte d′Ivoire. After extraction and chemical analysis of the essential oils, field trials were carried out using a Fisher block system with three treatment repetitions where their effects compared with those of a registered synthetic insecticide (IBIS A 52 EC). Foliar applications of the products were carried out in accordance with the cotton plant protection extension programme in Côte d′Ivoire from the 45th to the 115th day after plant emergence, with one application every fortnight. Twenty-three and forty compounds representing about 96 and 99 % of the oil composition of O. gratissimum and C. citratus respectively were elucidated. The most abundant compounds were p-cymene and thymol (O. gratissimum) and myrcene, neral and geranial (C. citratus). The essential oil of O. gratissimum at concentrations of 2 and 5 % showed insecticidal activity on all pests (biting-sucking and carpophagous), except the phyllophagous Syllepte derogata. C. citratus, at a low concentration (1 %), was particularly toxic to whiteflies (Bemisia tabaci), however, it favoured the action of beneficial insects, specifically black ants and ladybirds in the cotton plots, unlike the chemical product. EO of O. gratissimum (1.60 and 4.62 mg GALAE/g, respectively) and C. citratus (2.26 and 2.78 mg GALAE, respectively) exhibited also significant acetyl and butyryl cholinesterase inhibitors. Insecticide formulations based on the essential oils of O. gratissimum and C. citratus offer favourable prospects for their use in cotton cultivation as an alternative to chemical pesticides. 相似文献
913.
Plant and Soil - Changing precipitation regimes in semiarid ecosystems will affect the balance of soil carbon (C) input and release, but the net effect on soil C storage is unclear. We asked how... 相似文献
914.
Galectin-4-Regulated Delivery of Glycoproteins to the Brush Border Membrane of Enterocyte-Like Cells
Laurence Stechly Willy Morelle Anne-Frédérique Dessein Sabine André Georges Grard Dave Trinel Marie-José Dejonghe Emmanuelle Leteurtre Hervé Drobecq Germain Trugnan Hans Joachim Gabius and Guillemette Huet 《Traffic (Copenhagen, Denmark)》2009,10(4):438-450
We have previously reported that silencing of galectin-4 expression in polarized HT-29 cells perturbed apical biosynthetic trafficking and resulted in a phenotype similar to the inhibitor of glycosylation, 1-benzyl-2-acetamido-2-deoxy-β- d -galactopyranoside (GalNAcα- O -bn). We now present evidence of a lipid raft-based galectin-4-dependent mechanism of apical delivery of glycoproteins in these cells. First, galectin-4 recruits the apical glycoproteins in detergent-resistant membranes (DRMs) because these glycoproteins were depleted in DRMs isolated from galectin-4-knockdown (KD) HT-29 5M12 cells. DRM-associated glycoproteins were identified as ligands for galectin-4. Structural analysis showed that DRMs were markedly enriched in a series of complex N -glycans in comparison to detergent-soluble membranes. Second, in galectin-4-KD cells, the apical glycoproteins still exit the Golgi but accumulated inside the cells, showing that their recruitment within lipid rafts and their apical trafficking required the delivery of galectin-4 at a post-Golgi level. This lectin that is synthesized on free cytoplasmic ribosomes is externalized from HT-29 cells mostly in the apical medium and follows an apical endocytic–recycling pathway that is required for the apical biosynthetic pathway. Together, our data show that the pattern of N -glycosylation of glycoproteins serves as a recognition signal for endocytosed galectin-4, which drives the raft-dependent apical pathway of glycoproteins in enterocyte-like HT-29 cells. 相似文献
915.
P. Rompré F. A. Auger L. Germain V. Bouvard C. A. López Valle J. Thibault A. Le Duy 《In vitro cellular & developmental biology. Plant》1990,26(10):983-990
Summary Our laboratory has been involved in finding optimal conditions for producing dermal and skin equivalents. As an original approach,
a Box-Behnken experimental design was used to study the effects of the initial collagen and fibroblast concentrations and
the initial gel thickness on the contraction of dermal and skin equivalents. The final surface area of dermal equivalent varied
significantly with the initial concentration of collagen and fibroblast, whereas the initial thickness of gel had no appreciable
effect on the contraction of the dermal equivalent. When keratinocytes were grown on these dermal equivalents they produced
a very severe contraction, to an extent that all skin equivalents had a similar final surface area. This severe contraction
was independent of collagen and fibroblast concentrations. Models for the prediction of the final percentage contraction of
dermal and skin equivalents as a function of the initial concentration of collagen, the logarithm of fibroblast concentration,
and the initial gel thickness were obtained and analyzed. Keratinocytes grown at the lowest seeding density did not contract
the equivalents. However, histologic analysis has shown an incomplete coverage by these cells of the equivalents. The extensive
contraction of the skin equivalent presenting adequate morphology is a major drawback toward its clinical utilization for
burn wound coverage.
The financial supports for this project were received from Canadian NSERC postgraduate scholarship (P. Rompré), Québec FCAR
postgraduate scholarship (C.A. López Valle), France-Québec research grant in Biotechnology (F.A. Auger), Canadian MRC grant
(F.A. Auger), and NSERC grants (A. LeDuy and J. Thibault). 相似文献
916.
917.
918.
Saïda Khaoua Ahmed Lebrihi Pierre Germain Gerard Lefebvre 《Applied microbiology and biotechnology》1991,35(2):253-257
Summary The production of cephamycin C by Streptomyces cattleya varies with the use of asparagine, glutamine or ammonium as nitrogen sources. hydroxylase and expandase activities were demonstrated for the first time with this species. A study of the biosynthetic regulation of these enzymes by two different nitrogen sources, glutamine and asparagine, was carried out. Asparagine proved to be a better nitrogen source, both for enzymatic biosynthesis and production of cephamycin C. Moreover, an excess of asparagine in the culture environment provokes, simultaneously, a reduction in cephamycin C production and a decrease in the biosynthesis of expandase and hydroxylase.Offprint requests to: A. Lebrihi 相似文献
919.
Thomas Pradeu Bertrand Daignan-Fornier Andrew Ewald Pierre-Luc Germain Samir Okasha Anya Plutynski Sébastien Benzekry Marta Bertolaso Mina Bissell Joel S. Brown Benjamin Chin-Yee Ian Chin-Yee Hans Clevers Laurent Cognet Marie Darrason Emmanuel Farge Jean Feunteun Jérôme Galon Elodie Giroux Sara Green Fridolin Gross Fanny Jaulin Rob Knight Ezio Laconi Nicolas Larmonier Carlo Maley Alberto Mantovani Violaine Moreau Pierre Nassoy Elena Rondeau David Santamaria Catherine M. Sawai Andrei Seluanov Gregory D. Sepich-Poore Vanja Sisirak Eric Solary Sarah Yvonnet Lucie Laplane 《Biological reviews of the Cambridge Philosophical Society》2023,98(5):1668-1686
Cancers rely on multiple, heterogeneous processes at different scales, pertaining to many biomedical fields. Therefore, understanding cancer is necessarily an interdisciplinary task that requires placing specialised experimental and clinical research into a broader conceptual, theoretical, and methodological framework. Without such a framework, oncology will collect piecemeal results, with scant dialogue between the different scientific communities studying cancer. We argue that one important way forward in service of a more successful dialogue is through greater integration of applied sciences (experimental and clinical) with conceptual and theoretical approaches, informed by philosophical methods. By way of illustration, we explore six central themes: (i) the role of mutations in cancer; (ii) the clonal evolution of cancer cells; (iii) the relationship between cancer and multicellularity; (iv) the tumour microenvironment; (v) the immune system; and (vi) stem cells. In each case, we examine open questions in the scientific literature through a philosophical methodology and show the benefit of such a synergy for the scientific and medical understanding of cancer. 相似文献
920.
Michel Loreau Matthieu Barbier Elise Filotas Dominique Gravel Forest Isbell Steve J. Miller Jose M. Montoya Shaopeng Wang Raphaël Aussenac Rachel Germain Patrick L. Thompson Andrew Gonzalez Laura E. Dee 《Biological reviews of the Cambridge Philosophical Society》2021,96(5):2333-2354
Biological insurance theory predicts that, in a variable environment, aggregate ecosystem properties will vary less in more diverse communities because declines in the performance or abundance of some species or phenotypes will be offset, at least partly, by smoother declines or increases in others. During the past two decades, ecology has accumulated strong evidence for the stabilising effect of biodiversity on ecosystem functioning. As biological insurance is reaching the stage of a mature theory, it is critical to revisit and clarify its conceptual foundations to guide future developments, applications and measurements. In this review, we first clarify the connections between the insurance and portfolio concepts that have been used in ecology and the economic concepts that inspired them. Doing so points to gaps and mismatches between ecology and economics that could be filled profitably by new theoretical developments and new management applications. Second, we discuss some fundamental issues in biological insurance theory that have remained unnoticed so far and that emerge from some of its recent applications. In particular, we draw a clear distinction between the two effects embedded in biological insurance theory, i.e. the effects of biodiversity on the mean and variability of ecosystem properties. This distinction allows explicit consideration of trade-offs between the mean and stability of ecosystem processes and services. We also review applications of biological insurance theory in ecosystem management. Finally, we provide a synthetic conceptual framework that unifies the various approaches across disciplines, and we suggest new ways in which biological insurance theory could be extended to address new issues in ecology and ecosystem management. Exciting future challenges include linking the effects of biodiversity on ecosystem functioning and stability, incorporating multiple functions and feedbacks, developing new approaches to partition biodiversity effects across scales, extending biological insurance theory to complex interaction networks, and developing new applications to biodiversity and ecosystem management. 相似文献