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排序方式: 共有451条查询结果,搜索用时 15 毫秒
41.
Lellouch AC Watt GM Geremia RA Flitsch SL 《Biochemical and biophysical research communications》2000,272(1):290-292
The biochemical characterization of bacterial glycosyltransferases involved in the assembly of cell-wall-associated polysaccharides is often hindered by the lack of the appropriate undecaprenyl-pyrophosphate-linked acceptor substrate. In order to find a suitable synthetic substrate for the alpha1,3-mannosyltransferase AceA from Acetobacter xylinum, phytanyl-pyrophosphate-linked cellobiose was prepared. In the presence of GDP-[14C]mannose and recombinant AceA, the phytanyl-pyrophosphate-linked cellobiose afforded a 14C-labeled trisaccharide that was sensitive to alpha-mannosidase degradation in a fashion analogous to the natural undecaprenyl-pyrophosphate-linked cellobiose substrate. These results suggest that phytanyl-pyrophosphate-linked oligosaccharides may be useful substrates for other important bacterial glycosyltransferases. 相似文献
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Federica Zito Marino Giuseppina Liguori Gabriella Aquino Elvira La Mantia Silvano Bosari Stefano Ferrero Lorenzo Rosso Gabriella Gaudioso Nicla De Rosa Marianna Scrima Nicola Martucci Antonello La Rocca Nicola Normanno Alessandro Morabito Gaetano Rocco Gerardo Botti Renato Franco 《PloS one》2015,10(10)
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Silvano Fares Elina Oksanen Mika Lännenpää Riitta Julkunen-Tiitto Francesco Loreto 《Photosynthesis research》2010,104(1):61-74
Plants are exposed to increasing levels of tropospheric ozone concentrations. This pollutant penetrates in leaves through
stomata and quickly reacts inside leaves, thus making plants valuable ozone sinks, but at the same time triggers oxidation
processes which lead to leaf injuries. To counteract these negative effects, plants produce an array of antioxidants which
react with ozone and reactive molecules which ozone generates in the leaf tissues. In this study, we measured the effect of
an ozone concentration which is likely to be attained in many areas of the world in the near future (80 ppb) on leaves of
the vertical profile of the widespread agroforestry species Populus nigra. Changes in (1) physiological parameters (photosynthesis and stomatal conductance), (2) ozone uptake, (3) emission of volatile
organic compounds (VOCs, i.e. isoprene, methanol and other oxygenated compounds), (4) concentration of antioxidant surface
compounds, and (5) concentration of phenolic compounds were assessed. The aim was to assess whether the defensive pathways
leading to isoprenoids and phenolics formation were induced when a moderate and chronic increment of ozone is not able to
damage photosynthesis. No visual injuries and minor changes in physiology and ozone uptake were observed. The emission of
isoprene and oxygenated six-carbon (C6) volatiles were inhibited by ozone, whereas methanol emission was increased, especially
in developing leaves. We interpret these results as suggesting an ontogenetic shift in ozone-treated leaves, leading to a
slower development and a faster senescence. Most surface and phenolic compounds showed a declining trend in concentration
from the youngest to the fully expanded leaves. Ozone reduced the concentrations of chlorogenic acid derivatives at the leaf
surface, whereas in total leaf extracts a metabolic shift towards few phenolics with higher antioxidant capacity was observed. 相似文献
46.
The feeding behaviour of the shelled sacoglossan Oxynoe olivacea was investigated to better understand the role and importance of this species in influencing encroachments of the alien alga
Caulerpa taxifolia in the Mediterranean sea. We tested whether this slug preferred, as preliminary field observations suggested, an aggregative
feeding behaviour and which part of the algal thallus, phylloid vs rhizoid, it preferred. Results showed that O. olivacea fed in groups and actively selected phylloid. This outcome poses important questions regarding the possibility that this
species, fragmenting the alga thallus, could enhance dispersion and regeneration of C. taxifolia. 相似文献
47.
Long-term-care facilities (LTCFs) comprise a heterogeneous group of institutions that provide a wide variety of services to diverse groups of patients, most of whom are elderly. Infections are common in LTCFs and these are complicated by antimicrobial-resistant pathogens. The residents in LTCFs have a high frequency of colonization with antimicrobial-resistant organisms, including methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, penicillin-resistant pneumococci, extended spectrum P-lactamase-producing gram-negative organisms, and fluoroquinolone-resistant gram-negative organisms. Although several control programs have been published, up to now there still is a long way to go in this area of health care. This review will briefly touch upon the clinical relevance of antimicrobial resistance in LTCFs. 相似文献
48.
Piccinini Alexandre Oliveira Mariana Pacheco Silva Mariella Reinol Bett Gabriela Souza Becker Isabel Borges Mendes Talita Farias Salla Daniéle Hendler Silva Larissa Espindola Vilela Thais Ceresér Moraes Fernanda Mendes Moterle Diego Damiani Adriani Paganini Dagostin Lígia Salvan Tietbohl Lariani Tamires Bittencourt João Vitor Silvano Biehl Erica Denicol Tais Luise Bonfante Sandra Regina Andrade Vanessa Moraes Silveira Paulo Cesar Lock Prophiro Josiane Somariva Ferreira Gabriela Kozuchovski Petronilho Fabricia Kanis Luiz Alberto Rezin Gislaine Tezza 《Neurochemical research》2022,47(7):1888-1903
Neurochemical Research - This study aimed to evaluate the effect of Cynara cardunculus leaf ethanol extract on inflammatory and oxidative stress parameters in the hypothalamus, prefrontal cortex,... 相似文献
49.
Circuit modification associated with learning and memory involves multiple events, including the addition and remotion of newborn cells trough adulthood. Adult neurogenesis and gliogenesis were mainly described in models of voluntary exercise, enriched environments, spatial learning and memory task; nevertheless, it is unknown whether it is a common mechanism among different learning paradigms, like reward dependent tasks. Therefore, we evaluated cell proliferation, neurogenesis, astrogliogenesis, survival and neuronal maturation in the medial prefrontal cortex (mPFC) and the hippocampus (HIPP) during learning an operant conditioning task. This was performed by using endogenous markers of cell proliferation, and a bromodeoxiuridine (BrdU) injection schedule in two different phases of learning. Learning an operant conditioning is divided in two phases: a first phase when animals were considered incompletely trained (IT, animals that were learning the task) when they performed between 50% and 65% of the responses, and a second phase when animals were considered trained (Tr, animals that completely learned the task) when they reached 100% of the responses with a latency time lower than 5 seconds. We found that learning an operant conditioning task promoted cell proliferation in both phases of learning in the mPFC and HIPP. Additionally, the results presented showed that astrogliogenesis was induced in the medial prefrontal cortex (mPFC) in both phases, however, the first phase promoted survival of these new born astrocytes. On the other hand, an increased number of new born immature neurons was observed in the HIPP only in the first phase of learning, whereas, decreased values were observed in the second phase. Finally, we found that neuronal maturation was induced only during the first phase. This study shows for the first time that learning a reward-dependent task, like the operant conditioning, promotes neurogenesis, astrogliogenesis, survival and neuronal maturation depending on the learning phase in the mPFC-HIPP circuit. 相似文献
50.