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91.
Background
The genus Pseudomonas comprises more than 100 species of environmental, clinical, agricultural, and biotechnological interest. Although, the recommended method for discriminating bacterial species is DNA-DNA hybridisation, alternative techniques based on multigenic sequence analysis are becoming a common practice in bacterial species discrimination studies. Since there is not a general criterion for determining which genes are more useful for species resolution; the number of strains and genes analysed is increasing continuously. As a result, sequences of different genes are dispersed throughout several databases. This sequence information needs to be collected in a common database, in order to be useful for future identification-based projects. 相似文献92.
Sureda A Ferrer MD Tauler P Maestre I Aguiló A Córdova A Tur JA Roche E Pons A 《Free radical research》2007,41(8):874-883
We studied the effects of intense exercise on the neutrophil antioxidant enzyme activities and gene expression. Blood samples were taken from seven cyclists in basal conditions and 3 h after two competition stages of 165 km. Serum creatine kinase (CK) activity, plasma carbonyl derivatives and uric acid levels increased after exercise. The cycling stage induced neutrophilia and increased myeloperoxidase (MPO) activity and reactive oxygen species (ROS) production. Antioxidant enzyme activities (catalase, glutathione peroxidase and superoxide dismutase) decreased after exercise, although gene expression increased. Immunocytochemistry showed catalase (CAT) enzyme equally distributed between the cytoplasm and organelles before exercise, and after exercise the cytoplasmic CAT levels were reduced and were absent in the compartments. After in vitro stimulation with opsonized zymosan (OZ) the extracellular CAT levels increased. This suggests a CAT secretion in order to avoid neutrophil-induced oxidative damage at a local level or to regulate the function of ROS as extracellular signalling molecules. 相似文献
93.
Early environmental conditions may affect the development and manifestation of circadian rhythms. This study sought to determine whether the maintenance of rats under different T-cycles during lactation influences the subsequent degree of dissociation of the circadian rhythms of motor activity and core body temperature. Two groups of 22 day-old Wistar rats were kept after weaning under T-cycles of 22 h (T22) or 23 h (T23) for 70 days. Subsequently, they were kept in constant darkness (DD). Half of the animals in each group were born and reared under these experimental conditions, while the other half were reared until weaning under 24 h LD cycles (T24). Rats transferred from T24 to T22 or T23 showed two circadian components in motor activity and temperature, one entrained by light and the other free-running. In T22, there was also desynchronization between temperature and motor activity. Rats submitted to T23 from birth showed higher stability of the 23 h component than rats transferred from T24 to T23 after weaning. However, in comparison to rats born under T24 and subsequently changed to T22, animals submitted to T22 from birth showed shorter values of the period of the non-light-dependent component during T22, more aftereffects when transferred to DD, and a lack of desynchronization between motor activity and temperature. The results suggest that T-cycles in the early environment may modify overt rhythms by altering the internal coupling of the circadian pacemaker. 相似文献
94.
Catania MV D'Antoni S Bonaccorso CM Aronica E Bear MF Nicoletti F 《Molecular neurobiology》2007,35(3):298-307
Group I metabotropic glutamate receptors (mGlu1 and mGlu5) are coupled to polyphosphoinositide hydrolysis and are involved
in activity-dependent forms of synaptic plasticity, both during development and in the adult life. Group I mGlu receptors
can also regulate proliferation, differentiation, and survival of neural stem/progenitor cells, which further support their
role in brain development. An exaggerated response to activation of mGlu5 receptors may underlie synaptic dysfunction in Fragile
X syndrome, the most common inherited form of mental retardation. In addition, group I mGlu receptors are overexpressed in
dysplastic neurons of focal cortical dysplasia and hemimegaloencephaly, which are disorders of cortical development associated
with chronic epilepsy. Drugs that block the activity of group I mGlu receptors (in particular, mGlu5 receptors) are potentially
helpful for the treatment of Fragile X syndrome and perhaps other neurodevelopmental disorders. 相似文献
95.
Production of waste hair in the leather manufacturing industry is increasing every year due to the adoption of hair-save unhairing
techniques, leaving the tanners with the problem of coping with yet another solid by-product. Numerous potential strategies
for hair utilisation have been proposed. However, the use of hair waste as agricultural fertiliser is one of its most promising
applications due to the high nitrogen content of hair. Agricultural value of hair can be increased by composting. This paper
deals with the composting of hair from the unhairing of bovine hide. Results indicated that hair cannot be either composted
on its own or co-composted with de-inking sludge, a chemical complementary co-substrate. However, good results were obtained
when co-composted with raw sludge from a municipal wastewater treatment plant at hair:raw sludge weight ratios 1:1, 1:2 and,
1:4 in lab scale and pilot plant scale composters. In all cases, a more stable product was achieved at the end of the process.
Composting in the pilot plant composter was effectively monitored using Static Respiration Indices determined at process temperature
at sampling (SRI
T
) and at 37°C (SRI37). Notably, SRI
T
values were more sensitive to changes in the biological activity. In contrast, Respiratory Quotient (RQ) values were not
adequate to follow the development of the process. 相似文献
96.
Australia, the flattest, driest, and geologically oldest vegetated continent, has a uniquely high proportion of nutrient-poor soils. We develop a "Nutrient-Poverty/Intense-Fire Theory," which postulates that most anomalous features of organisms and ecosystems of Australia are the evolutionary consequences of adaptations to nutrient poverty, compounded by intense fire that tends to occur as a result of nutrient poverty. The fundamental tenet of the theory is that plants growing in environments with plentiful light and periodic adequate moisture, but on soils poor in phosphorus, zinc, and other indispensible nutrients, can synthesize carbohydrates in excess of the amount that can be combined with, or catalyzed by, these nutrients for metabolism and production of nutrient-rich foliage and reproductive tissues. They use this "expendable energy" to produce well-defended foliage, large quantities of lignified tissues, and readily digestible exudates. Rapid accumulation of nutrient-poor biomass, a result of low rates of herbivory, provides fuel for intense fire. Intense fire exacerbates nutrient poverty by volatilizing certain micronutrients critical for animals. Anomalous features of organisms of Australia that can be explained by this theory, rather than by climate or phylogenetic history alone, include the following: most woody plants have long-lived, durable foliage; plants defend their tissues primarily with carbon-rich but nutrient-poor compounds; an unusually high proportion of plants protects seeds from fire and granivores in sturdy, woody capsules or follicles; plants allocate unusually large amounts of expendable energy to production of carbon-based exudates, such as nectar and gums; an unusually high proportion of plant species is pollinated by vertebrates that average larger size than pollinators on other continents; herbivores are small and have slow metabolism; there are no ruminants, mammals that eat mainly subterranean plant matter, or fungus-culturing termites and ants; vegetation dominated by leaf-spinescent plants is more extensive than vegetation dominated by stem-spinescent plants; nitrogen-fixing plants are major components of most vegetation types; there is a higher proportion of myrmecochorous plant species than on any other continent; there are hardly any stem-succulent and few leaf-succulent, perennial, non-halophytic plant species; and an unusually high proportion of bird species breeds cooperatively. Although the Nutrient-Poverty/Intense-Fire Theory can provide plausible explanations for these anomalous features, some puzzles remain, among them the great success of introduced herbivores, the lack of grazers on extensive grasslands on cracking clays, the apparently low productivity of ants, and the prominence of the parasitic plants of Australia. By examining the ratios of available energy to nutrients, particularly scarce nutrients, ecologists may identify processes not previously recognized as important for life forms or biotic adaptation on other continents. 相似文献
97.
Noori Tayebeh Shirooie Samira Sureda Antoni Sobarzo-Sanchez Eduardo Dehpour Ahmad Reza Saldías Marianela Akkol Esra Küpeli 《Neurochemical research》2022,47(8):2142-2157
Neurochemical Research - Stroke is a sudden neurological disorder that occurs due to impaired blood flow to an area of the brain. Stroke can be caused by the blockage or rupture of a blood vessel... 相似文献
98.
Dalil Hannani Marie Vétizou David Enot Sylvie Rusakiewicz Nathalie Chaput David Klatzmann Melanie Desbois Nicolas Jacquelot Nadège Vimond Salem Chouaib Christine Mateus James P Allison Antoni Ribas Jedd D Wolchok Jianda Yuan Philip Wong Michael Postow Andrzej Mackiewicz Jacek Mackiewicz Dirk Schadendorff Dirk Jaeger Alan J Korman Keith Bahjat Michele Maio Luana Calabro Michele WL Teng Mark J Smyth Alexander Eggermont Caroline Robert Guido Kroemer Laurence Zitvogel 《Cell research》2015,25(2):208-224
The cytotoxic T lymphocyte antigen-4 (CTLA-4)-blocking antibody ipilimumab induces immune-mediated long-term control of metastatic melanoma in a fraction of patients. Although ipilimumab undoubtedly exerts its therapeutic effects via immunostimulation, thus far clinically useful, immunologically relevant biomarkers that predict treatment efficiency have been elusive. Here, we show that neutralization of IL-2 or blocking the α and β subunits of the IL-2 receptor (CD25 and CD122, respectively) abolished the antitumor effects and the accompanying improvement of the ratio of intratumoral T effector versus regulatory cells (Tregs), which were otherwise induced by CTLA-4 blockade in preclinical mouse models. CTLA-4 blockade led to the reduction of a suppressive CD4+ T cell subset expressing Lag3, ICOS, IL-10 and Egr2 with a concomitant rise in IL-2-producing effector cells that lost FoxP3 expression and accumulated in regressing tumors. While recombinant IL-2 improved the therapeutic efficacy of CTLA-4 blockade, the decoy IL-2 receptor α (IL-2Rα, sCD25) inhibited the anticancer effects of CTLA-4 blockade. In 262 metastatic melanoma patients receiving ipilimumab, baseline serum concentrations of sCD25 represented an independent indicator of overall survival, with high levels predicting resistance to therapy. Altogether, these results unravel a role for IL-2 and IL-2 receptors in the anticancer activity of CTLA-4 blockade. Importantly, our study provides the first immunologically relevant biomarker, namely elevated serum sCD25, that predicts resistance to CTLA-4 blockade in patients with melanoma. 相似文献
99.
Family 16 carbohydrate active enzyme members Bacillus licheniformis 1,3-1,4-β-glucanase and Populus tremula x tremuloides xyloglucan endotransglycosylase (XET16-34) are highly structurally related but display different substrate specificities. Although the first binds linear gluco-oligosaccharides, the second binds branched xylogluco-oligosaccharides. Prior engineered nucleophile mutants of both enzymes are glycosynthases that catalyze the condensation between a glycosyl fluoride donor and a glycoside acceptor. With the aim of expanding the glycosynthase technology to produce designer oligosaccharides consisting of hybrids between branched xylogluco- and linear gluco-oligosaccharides, enzyme engineering on the negative subsites of 1,3-1,4-β-glucanase to accept branched substrates has been undertaken. Removal of the 1,3-1,4-β-glucanase major loop and replacement with that of XET16-34 to open the binding cleft resulted in a folded protein, which still maintained some β-glucan hydrolase activity, but the corresponding nucleophile mutant did not display glycosynthase activity with either linear or branched glycosyl donors. Next, point mutations of the 1,3-1,4-β-glucanase β-sheets forming the binding site cleft were mutated to resemble XET16-34 residues. The final chimeric protein acquired binding affinity for xyloglucan and did not bind β-glucan. Therefore, binding specificity has been re-engineered, but affinity was low and the nucleophile mutant of the chimeric enzyme did not show glycosynthase activity to produce the target hybrid oligosaccharides. Structural analysis by X-ray crystallography explains these results in terms of changes in the protein structure and highlights further engineering approaches toward introducing the desired activity. 相似文献
100.
Barberán A Fernández-Guerra A Auguet JC Galand PE Casamayor EO 《Molecular ecology》2011,20(9):1988-1996
Despite its widespread distribution and high levels of phylogenetic diversity, microbes are poorly understood creatures. We applied a phylogenetic ecology approach in the Kingdom Euryarchaeota (Archaea) to gain insight into the environmental distribution and evolutionary history of one of the most ubiquitous and largely unknown microbial groups. We compiled 16S rRNA gene sequences from our own sequence libraries and public genetic databases for two of the most widespread mesophilic Euryarchaeota clades, Lake Dagow Sediment (LDS) and Rice Cluster-V (RC-V). The inferred population history indicated that both groups have undergone specific nonrandom evolution within environments, with several noteworthy habitat transition events. Remarkably, the LDS and RC-V groups had enormous levels of genetic diversity when compared with other microbial groups, and proliferation of sequences within each single clade was accompanied by significant ecological differentiation. Additionally, the freshwater Euryarchaeota counterparts unexpectedly showed high phylogenetic diversity, possibly promoted by their environmental adaptability and the heterogeneous nature of freshwater ecosystems. The temporal phylogenetic diversification pattern of these freshwater Euryarchaeota was concentrated both in early times and recently, similarly to other much less diverse but deeply sampled archaeal groups, further stressing that their genetic diversity is a function of environment plasticity. For the vast majority of living beings on Earth (i.e. the uncultured microorganisms), how they differ in the genetic or physiological traits used to exploit the environmental resources is largely unknown. Inferring population history from 16S rRNA gene-based molecular phylogenies under an ecological perspective may shed light on the intriguing relationships between lineage, environment, evolution and diversity in the microbial world. 相似文献