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排序方式: 共有172条查询结果,搜索用时 15 毫秒
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Thayná de Souza Silva Júlia M. B. Silva Gláucia H. Braun Jennyfer A. A. Mejia Gari V. C. Ccapatinta Mário Ferreira Conceição Santos Matheus H. Tanimoto Jairo K. Bastos Renato L. T. Parreira Renato P. Orenha Alexandre Borges Andresa A. Berretta Rodrigo C. S. Veneziani Carlos H. G. Martins Sérgio R. Ambrósio 《化学与生物多样性》2021,18(8):e2100307
Brazilian green and red propolis stand out as commercial products for different medical applications. In this article, we report the antimicrobial activities of the hydroalcoholic extracts of green (EGP) and red (ERP) propolis, as well as guttiferone E plus xanthochymol (8) and oblongifolin B (9) from red propolis, against multidrug-resistant bacteria (MDRB). We undertook the minimal inhibitory (MIC) and bactericidal (MBC) concentrations, inhibition of biofilm formation (MICB50), catalase, coagulase, DNase, lipase, and hemolysin assays, along with molecular docking simulations. ERP was more effective by displaying MIC and MBC values <100 μg mL−1. Compounds 8 and 9 displayed the lowest MIC values (0.98 to 31.25 μg mL−1) against all tested Gram-positive MDRB. They also inhibited the biofilm formation of S. aureus (ATCC 43300 and clinical isolate) and S. epidermidis (ATCC 14990 and clinical isolate), with MICB50 values between 1.56 and 6.25 μg mL−1. The molecular docking results indicated that 8 and 9 might interact with the catalase's amino acids. Compounds 8 and 9 have great antimicrobial potential. 相似文献
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Climate change poses an unprecedented threat to biodiversity worldwide. Consequently, unrecognised taxa may not receive adequate conservation attention to survive. We used molecular and morphological data to address the challenge of species delimitation within the genus Schilbe. The presence or absence of an adipose fin and distribution based on east-flowing, conceivably faster-flowing, or west-flowing, probably more slow-flowing, river systems were considered. Distinctive geographic patterns in genetic variation within southern, eastern, and western African populations were revealed. Particularly, the South African population is distinct from those of Namibia, Botswana and Nigeria. No individuals with rudimentary adipose fins were found at any locality, but specimens from three localities either had or did not have adipose fins. These mixed occurrences are suspected to be a result of human interventions, and that the presence of rudimentary adipose fins in the east African species could be an adaptive feature that serves to stabilise these fish in faster currents. In addition, the genetic divergence observed among African silver catfish from geographically isolated river systems is conceivably the result of micro-evolutionary adaptive responses to different environmental conditions. Collectively, these results distinguish S. depressirostris from S. intermedius. 相似文献
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Reconquering the water: Evolution and systematics of South and Central American aquatic lizards (Gymnophthalmidae)
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Sergio Marques‐Souza Ivan Prates Antoine Fouquet Agustín Camacho Philippe J. R. Kok Pedro M. S. Nunes Francisco Dal Vechio Renato Sousa Recoder Nathalia Mejia Mauro Teixeira Junior Cesar Barrio‐Amorós José Cassimiro Jucivaldo Dias Lima Marco Aurélio de Sena Miguel Trefaut Rodrigues 《Zoologica scripta》2018,47(3):255-265
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Francine H. Mejia Valerie Ouellet Martin A. Briggs Stephanie M. Carlson Roser Casas-Mulet Mollie Chapman Mathias J. Collins Stephen J. Dugdale Joseph L. Ebersole Danielle M. Frechette Aimee H. Fullerton Carole-Anne Gillis Zachary C. Johnson Christa Kelleher Barret L. Kurylyk Rebecca Lave Benjamin H. Letcher Knut M. Myrvold Tracie-Lynn Nadeau Helen Neville Herve Piégay Kathryn A. Smith Diego Tonolla Christian E. Torgersen 《Global Change Biology》2023,29(19):5482-5508
Human activities and climate change threaten coldwater organisms in freshwater ecosystems by causing rivers and streams to warm, increasing the intensity and frequency of warm temperature events, and reducing thermal heterogeneity. Cold-water refuges are discrete patches of relatively cool water that are used by coldwater organisms for thermal relief and short-term survival. Globally, cohesive management approaches are needed that consider interlinked physical, biological, and social factors of cold-water refuges. We review current understanding of cold-water refuges, identify gaps between science and management, and evaluate policies aimed at protecting thermally sensitive species. Existing policies include designating cold-water habitats, restricting fishing during warm periods, and implementing threshold temperature standards or guidelines. However, these policies are rare and uncoordinated across spatial scales and often do not consider input from Indigenous peoples. We propose that cold-water refuges be managed as distinct operational landscape units, which provide a social and ecological context that is relevant at the watershed scale. These operational landscape units provide the foundation for an integrated framework that links science and management by (1) mapping and characterizing cold-water refuges to prioritize management and conservation actions, (2) leveraging existing and new policies, (3) improving coordination across jurisdictions, and (4) implementing adaptive management practices across scales. Our findings show that while there are many opportunities for scientific advancement, the current state of the sciences is sufficient to inform policy and management. Our proposed framework provides a path forward for managing and protecting cold-water refuges using existing and new policies to protect coldwater organisms in the face of global change. 相似文献
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Dennis V Pedersen Gregers R Andersen Dennis V Pedersen Lubka Roumenina Rasmus K Jensen Trine AF Gadeberg Chiara Marinozzi Capucine Picard Tania Rybkine Steffen Thiel Uffe BS Sørensen Cordula Stover Veronique Fremeaux-Bacchi Gregers R Andersen 《The EMBO journal》2017,36(8):1084-1099
Properdin (FP) is an essential positive regulator of the complement alternative pathway (AP) providing stabilization of the C3 and C5 convertases, but its oligomeric nature challenges structural analysis. We describe here a novel FP deficiency (E244K) caused by a single point mutation which results in a very low level of AP activity. Recombinant FP E244K is monomeric, fails to support bacteriolysis, and binds weakly to C3 products. We compare this to a monomeric unit excised from oligomeric FP, which is also dysfunctional in bacteriolysis but binds the AP proconvertase, C3 convertase, C3 products and partially stabilizes the convertase. The crystal structure of such a FP-convertase complex suggests that the major contact between FP and the AP convertase is mediated by a single FP thrombospondin repeat and a small region in C3b. Small angle X-ray scattering indicates that FP E244K is trapped in a compact conformation preventing its oligomerization. Our studies demonstrate an essential role of FP oligomerization in vivo while our monomers enable detailed structural insight paving the way for novel modulators of complement. 相似文献
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