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91.
A suitable and rapid method for the simultaneous determination of different aliphatic penicillins is described. Butyryl-, pentanoyl-, hexanoyl-, heptanoyl-, octanoyl-, nonanoyl- and decanoylpenicillin can be completely separated by high-performance liquid chromatography using an isocratic elution mode (50 mM H2KPO4, pH 5.0:methanol, 45:55 v/v). Under these conditions, retention times for C4 to C10 aliphatic side-chain penicillins were 2.5, 2.8, 4.1, 5.8, 8.9, 15.3, and 28.2 min. The benzylpenicillin retention time was 3.3 min. 相似文献
92.
When a mixture of sugarcane tops, alfalfa (20%) and milled malt (0.5%) was ensiled, a pronounced decrease of pH was observed
during the first week corresponding to a rapid production of laotic and acetic acids. After that pH and acid production detached.
The number of microorganisms increased during the first days of silage. Then aerobes rapidly decreased and were the fewer
after 50 days of silage. Anaerobes also decreased but not so substantially. Lactic aoid producers rose very quickly during
the first 4–5 days to became more or less constant after that. Filamentous fungi were predominant at the beginning among the
fungal population, but later on almost disappeared and yeasts were found instead. During the silage process the amount of
total reducing hydrolyzate increased and readily utilizable sugars were found after the microbial activity had ceased. 相似文献
93.
Weanling rats of both sexes were submitted to either castration, or castration together with periodic injections of testicular extract to males or of ovarian extract to females. Control and experimental animals were sampled at 63 days of age. Cranial differentiation between sexes was estimated by Mahalanobis D2 distances. The controls showed a significant sexual cranial difference. Orchidectomy decreased cranial differences and this effect was compensated by injections of testicular extract. On the other hand, oophorectomy increased cranial differences, which were diminished by injections of ovarian extract. Sexual cranial dimorphism in the normal rat seems to be the result of a counteracting effect between testicular and ovarian hormonal secretions. 相似文献
94.
N Tolosa de Talamoni D Hauen de Bronia R Pereira J Moreno F Ca?as 《Biochemistry international》1987,15(6):1115-1125
Cholecalciferol administration to vitamin D-deficient chicks produces, 24 h after treatment, a specific increase of the phosphatidylcholine content in the intestinal mitochondrial inner membrane plus matrix fraction without changes in its proportion in the outer membrane. The ratio of unsaturated/saturated fatty acids in the outer membrane phosphatidylcholine was increased by that treatment. The inner membrane plus matrix presents a decrease of 16:1 in phosphatidylethanolamine and 18:0 in the phosphatidylcholine fraction. Cardiolipin shows the largest change in the ratio of unsaturated/saturated fatty acids predominantly by an increase in the linoleic acid. The present data suggest that phosphatidylcholine and fatty acids modifications in both mitochondrial subfractions caused by vitamin D3 might have some role in the intestinal mitochondrial Ca transport. 相似文献
95.
Beatriz Pereira Moreno Gislaine Cristiane Mantovanelli Letycia Lopes Ricardo Adriano Antnio Silva Rubem Silvrio De Oliveira Emy Luiza Ishii‐Iwamoto Maria Helena Sarragiotto Debora Cristina Baldoqui 《化学与生物多样性》2020,17(3)
Studies of the phytotoxic effects between plants can be a crucial tool in the discovery of innovative compounds with herbicide potential. In this sense, we can highlight ruzigrass (Urochloa ruziziensis), which is traditionally used in the crop rotation system in order to reduce weed emergence. The aim of this work was to characterize the secondary metabolites of ruzigrass and to evaluate its phytotoxic effects. In total, eight compounds were isolated: friedelin, oleanolic acid, α‐amyrin, 1‐dehydrodiosgenone, sitosterol and stigmasterol glycosides, tricin and p‐coumaric acid. Phytotoxic effects of the crude methanolic extract and fractions of ruzigrass were assessed using germination rate, initial seedling growth, and biomass of Bidens pilosa, Euphorbia heterophylla and Ipomoea grandifolia. Chemometric analysis discriminated the weed species into three groups, and B. pilosa was the most affected by fractions of ruzigrass. The phytotoxic activities of 1‐dehydrodiosgenone, tricin, and p‐coumaric acid are also reported, and p‐coumaric acid and 1‐dehydrodiosgenone were active against B. pilosa. 相似文献
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98.
Amy E. Zanne Kessy Abarenkov Michelle E. Afkhami Carlos A. Aguilar‐Trigueros Scott Bates Jennifer M. Bhatnagar Posy E. Busby Natalie Christian William K. Cornwell Thomas W. Crowther Habacuc Flores‐Moreno Dimitrios Floudas Romina Gazis David Hibbett Peter Kennedy Daniel L. Lindner Daniel S. Maynard Amy M. Milo Rolf Henrik Nilsson Jeff Powell Mark Schildhauer Jonathan Schilling Kathleen K. Treseder 《Biological reviews of the Cambridge Philosophical Society》2020,95(2):409-433
Fungi play many essential roles in ecosystems. They facilitate plant access to nutrients and water, serve as decay agents that cycle carbon and nutrients through the soil, water and atmosphere, and are major regulators of macro‐organismal populations. Although technological advances are improving the detection and identification of fungi, there still exist key gaps in our ecological knowledge of this kingdom, especially related to function . Trait‐based approaches have been instrumental in strengthening our understanding of plant functional ecology and, as such, provide excellent models for deepening our understanding of fungal functional ecology in ways that complement insights gained from traditional and ‐omics‐based techniques. In this review, we synthesize current knowledge of fungal functional ecology, taxonomy and systematics and introduce a novel database of fungal functional traits (FunFun). FunFun is built to interface with other databases to explore and predict how fungal functional diversity varies by taxonomy, guild, and other evolutionary or ecological grouping variables. To highlight how a quantitative trait‐based approach can provide new insights, we describe multiple targeted examples and end by suggesting next steps in the rapidly growing field of fungal functional ecology. 相似文献
99.
Olga P. Nyssen Angeles Perez‐Aisa Luis Rodrigo Manuel Castro Pilar Mata Romero Juan Ortuo Jesus Barrio Jose Maria Huguet Ines Modollel Noelia Alcaide Alfredo Lucendo Xavier Calvet Monica Perona Barbara Gomez Blas Jose Gomez Rodriguez Pilar Varela Manuel Jimenez‐Moreno Manuel Dominguez‐Cajal Liliana Pozzati Diego Burgos Luis Bujanda Jenifer Hinojosa Javier Molina‐Infante Tommaso Di Maira Luis Ferrer Luis Fernndez‐Salazar Ariadna Figuerola Llucia Tito Cristobal de la Coba Judith Gomez‐Camarero Nuria Fernandez Maria Caldas Ana Garre Elena Resina Ignasi Puig Colm OMorain Francis Megraud Javier P. Gisbert 《Helicobacter》2020,25(5)
100.
Hector Moreno Alberto Rastrojo Rhys Pryce Chiara Fedeli Gert Zimmer Thomas A. Bowden Gisa Gerold Stefan Kunz 《PLoS neglected tropical diseases》2020,14(12)
A detailed understanding of the mechanisms underlying the capacity of a virus to break the species barrier is crucial for pathogen surveillance and control. New World (NW) mammarenaviruses constitute a diverse group of rodent-borne pathogens that includes several causative agents of severe viral hemorrhagic fever in humans. The ability of the NW mammarenaviral attachment glycoprotein (GP) to utilize human transferrin receptor 1 (hTfR1) as a primary entry receptor plays a key role in dictating zoonotic potential. The recent isolation of Tacaribe and lymphocytic choriominingitis mammarenaviruses from host-seeking ticks provided evidence for the presence of mammarenaviruses in arthropods, which are established vectors for numerous other viral pathogens. Here, using next generation sequencing to search for other mammarenaviruses in ticks, we identified a novel replication-competent strain of the NW mammarenavirus Tamiami (TAMV-FL), which we found capable of utilizing hTfR1 to enter mammalian cells. During isolation through serial passaging in mammalian immunocompetent cells, the quasispecies of TAMV-FL acquired and enriched mutations leading to the amino acid changes N151K and D156N, within GP. Cell entry studies revealed that both substitutions, N151K and D156N, increased dependence of the virus on hTfR1 and binding to heparan sulfate proteoglycans. Moreover, we show that the substituted residues likely map to the sterically constrained trimeric axis of GP, and facilitate viral fusion at a lower pH, resulting in viral egress from later endosomal compartments. In summary, we identify and characterize a naturally occurring TAMV strain (TAMV-FL) within ticks that is able to utilize hTfR1. The TAMV-FL significantly diverged from previous TAMV isolates, demonstrating that TAMV quasispecies exhibit striking genetic plasticity that may facilitate zoonotic spillover and rapid adaptation to new hosts. 相似文献