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991.
992.
Maturation and trafficking markers on rotavirus-specific B cells during acute infection and convalescence in children
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Jaimes MC Rojas OL Kunkel EJ Lazarus NH Soler D Butcher EC Bass D Angel J Franco MA Greenberg HB 《Journal of virology》2004,78(20):10967-10976
We have previously studied B cells, from people and mice, that express rotavirus-specific surface immunoglobulin (RV-sIg) by flow cytometry with recombinant virus-like particles that contain green fluorescent protein. In the present study we characterized circulating B cells with RV-sIg in children with acute and convalescent infection. During acute infection, circulating RV-sIgD(-) B cells are predominantly large, CD38(high), CD27(high), CD138(+/-), CCR6(-), alpha4beta7(+), CCR9(+), CCR10(+), cutaneous lymphocyte antigen-negative (CLA(-)), L-selectin(int/-), and sIgM(+), sIgG(-), sIgA(+/-) lymphocytes. This phenotype likely corresponds to gut-targeted plasma cells and plasmablasts. During convalescence the phenotype switches to small and large lymphocytes, CD38(int/-), CD27(int/-), CCR6(+), alpha4beta7(+/-), CCR9(+/-) and CCR10(-), most likely representing RV-specific memory B cells with both gut and systemic trafficking profiles. Of note, during acute RV infection both total and RV-specific murine IgM and IgA antibody-secreting cells migrate efficiently to CCL28 (the CCR10 ligand) and to a lesser extent to CCL25 (the CCR9 ligand). Our results show that CCR10 and CCR9 can be expressed on IgM as well as IgA antibody-secreting cells in response to acute intestinal infection, likely helping target these cells to the gut. However, these intestinal infection-induced plasmablasts lack the CLA homing receptor for skin, consistent with mechanisms of differential CCR10 participation in skin T versus intestinal plasma cell homing. Interestingly, RV memory cells generally lack CCR9 and CCR10 and instead express CCR6, which may enable recruitment to diverse epithelial sites of inflammation. 相似文献
993.
Rice NTRC is a high-efficiency redox system for chloroplast protection against oxidative damage
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Pérez-Ruiz JM Spínola MC Kirchsteiger K Moreno J Sahrawy M Cejudo FJ 《The Plant cell》2006,18(9):2356-2368
One of the mechanisms plants have developed for chloroplast protection against oxidative damage involves a 2-Cys peroxiredoxin, which has been proposed to be reduced by ferredoxin and plastid thioredoxins, Trx x and CDSP32, the FTR/Trx pathway. We show that rice (Oryza sativa) chloroplast NADPH THIOREDOXIN REDUCTASE (NTRC), with a thioredoxin domain, uses NADPH to reduce the chloroplast 2-Cys peroxiredoxin BAS1, which then reduces hydrogen peroxide. The presence of both NTR and Trx-like domains in a single polypeptide is absolutely required for the high catalytic efficiency of NTRC. An Arabidopsis thaliana knockout mutant for NTRC shows irregular mesophyll cell shape, abnormal chloroplast structure, and unbalanced BAS1 redox state, resulting in impaired photosynthesis rate under low light. Constitutive expression of wild-type NTRC in mutant transgenic lines rescued this phenotype. Moreover, prolonged darkness followed by light/dark incubation produced an increase in hydrogen peroxide and lipid peroxidation in leaves and accelerated senescence of NTRC-deficient plants. We propose that NTRC constitutes an alternative system for chloroplast protection against oxidative damage, using NADPH as the source of reducing power. Since no light-driven reduced ferredoxin is produced at night, the NTRC-BAS1 pathway may be a key detoxification system during darkness, with NADPH produced by the oxidative pentose phosphate pathway as the source of reducing power. 相似文献
994.
Hatching order and size-dependent mortality in relation to brood sex ratio composition in chinstrap penguins 总被引:2,自引:0,他引:2
Fargallo Juan A.; Polo Vicente; de Neve Liesbeth; Martin Jose; Davila Jose A.; Soler Manuel 《Behavioral ecology》2006,17(5):772-778
The differential environmental sensitivity of the sexes hasstrong implications in the evolutionary history of species asit can alter sexual size dimorphism, population sex ratios,and the faculty of parents to manipulate offspring sex in relationto environmental conditions. We studied sexual differences inhatching patterns and evaluated sex- and size-related mortalityin relation to hatching order and brood sex ratios in the chinstrappenguin Pygoscelis antarctica, a moderately size-dimorphic species,with a modal clutch size of 2 eggs. We found that male, second-hatched,and large eggs showed shorter hatching periods than female,first-hatched, and small eggs. We also found a male-biased mortalityof nestlings in the colony. However, male mortality patternsdiffered depending on the brood sex ratio composition. Mortalityof male chicks in all-male broods was higher than in mixed broodsand higher than female mortality in all-female broods. Contrary,females from mixed brood showed higher mortality than theirmale nest mates and higher too than females in all-female broods.Second-hatched chicks also suffered from higher mortality thanfirst-hatched chicks. Our results indicate that both the superiorcompetitive capacity and the higher energy demand of the largersex constitute 2 causal factors explaining patterns of sex-biasedmortality. Both factors occur in the same species and in differentsituations of sibling competition shaped by brood sex ratiocomposition. This study constitutes a good example of how patternsof sex-related mortality can vary depending on nest environmentalcircumstances. Furthermore, our study suggests that hatchingperiod can be a mechanism underlying sexual differences in theembryonic period of birds. 相似文献
995.
Manuel Rodríguez-Concepción 《Phytochemistry Reviews》2006,5(1):1-15
Isoprenoids are produced in all organisms but are especially abundant and diverse in plants. Two separate pathways operate in plant cells to synthesize prenyl diphosphate precursors common to all isoprenoids. Cytosolic and mitochondrial precursors are produced by the mevalonic acid (MVA) pathway whereas the recently discovered methylerythritol phosphate (MEP) pathway is located in plastids. However, both pathways may participate in the synthesis of at least some isoprenoids under certain circumstances. Although genes encoding all the enzymes from both pathways have already been cloned, little is known about the regulatory mechanisms that control the supply of isoprenoid precursors. Genetic approaches are providing valuable information on the regulation of both pathways. Thus, recent data from overexpression experiments in transgenic plants show that several enzymes share control over the metabolic flux through the MEP pathway, whereas a single regulatory step has been proposed for the MVA pathway. Identification of Arabidopsis thaliana mutants that are resistant to the inhibition of the MVA and the MEP pathways is a promising approach to uncover mechanisms involved in the crosstalk between pathways. The characterization of some of these mutants impaired in light perception and signaling has recently provided genetic evidence for a role of light as a key factor to modulate the availability of isoprenoid precursors in Arabidopsis seedlings. The picture emerging from recent data supports that a complex regulatory network appears to be at work in plant cells to ensure the supply of isoprenoid precursors when needed. 相似文献
996.
997.
Treatment of Biogas Produced in Anaerobic Reactors for Domestic Wastewater: Odor Control and Energy/Resource Recovery 总被引:1,自引:0,他引:1
Adalberto Noyola Juan Manuel Morgan-Sagastume Jorge E. López-Hernández 《Reviews in Environmental Science and Biotechnology》2006,5(1):93-114
Anaerobic municipal wastewater treatment in developing countries has important potential applications considering their huge
lack of sanitation infrastructure and their advantageous climatic conditions. At present, among the obstacles that this technology
encounters, odor control and biogas utilization or disposal should be properly addressed. In fact, in most of small and medium
size anaerobic municipal treatment plants, biogas is just vented, transferring pollution from water to the atmosphere, contributing
to the greenhouse gas inventory. Anaerobic municipal sewage treatment should not be considered as an energy producer, unless
a significant wastewater flow is treated. In these cases, more than half of the methane produced is dissolved and lost in
the effluent so yield values will be between 0.08 and 0.18 N m3 CH4/kg COD removed. Diverse technologies for odor control and biogas cleaning are currently available. High pollutant concentrations
may be treated with physical-chemical methods, while biological processes are used mainly for odor control to prevent negative
impacts on the treatment facilities or nearby areas. In general terms, biogas treatment is accomplished by physico-chemical
methods, scrubbing being extensively used for H2S and CO2 removal. However, dilution (venting) has been an extensive disposal method in some small- and medium-size anaerobic plants
treating municipal wastewaters. Simple technologies, such as biofilters, should be developed in order to avoid this practice,
matching with the simplicity of anaerobic wastewater treatment processes. In any case, design and specification of biogas
handling system should consider safety standards. Resource recovery can be added to anaerobic sewage treatment if methane
is used as electron donor for denitrification and nitrogen control purposes. This would result in a reduction of operational
cost and in an additional advantage for the application of anaerobic sewage treatment. In developing countries, biogas conversion
to energy may apply for the clean development mechanism (CDM) of the Kyoto Protocol. This would increase the economic feasibility
of the project through the marketing of certified emission reductions (CERs). 相似文献
998.
Analysis of parvalbumin fractions through proteomic methodologies allowed the differential classification of ten commercial, closely related species of the family Merlucciidae. Muscle extracts from nine hake species of the genus Merluccius including two subspecies of Merluccius australis (australis and polylepsis) and one grenadier species Macruronus novaezelandiae with two populations (novaezelandiae and magellanicus) were evaluated by 2-DE and MALDI-TOF MS. 2-DE demonstrated that the species tested displayed a low intra-specific degree of polymorphism and the isoform patterns were noticeably species-specific. MALDI-TOF mass fingerprints showed clear differences in the pattern of peptides produced by tryptic digestion between the Merluccius and the Macruronus, making the genus differentiation possible. In addition, a selective peptide mass present in the spectra from certain hakes allowed its classification in two groups: Euro-African and American hakes. Besides, some specific masses allowed a clearly individual identification for M. bilinearis, M. australis polylepsis, M. australis australis, M. productus, M. paradoxus and M. polli, while the rest of the hake species can be grouped in two clusters, comprising M. hubbsi and M. gayi in one and M. merluccius and M. capensis in the other. 相似文献
999.
The growth of Escherichia coli cells is impaired at temperatures below 21 degrees C and stops at 7.5 degrees C; however, growth of a transgenic strain producing the cold-adapted chaperones Cpn60 and Cpn10 from the psychrophilic bacterium Oleispira antarctica is good at low temperatures. The E. coli cpn(+) transgene offers a novel opportunity for examining the essential protein for cell viability at low temperatures. By screening a large-scale protein map (proteome) of cells of K-12 and its Cpn(+) transgene incubated at 4 degrees C, we identified 22 housekeeping proteins involved in systems failure of E. coli when confronted with low temperature. Through co-immunoprecipitation of Cpn60, Northern blot, and in vitro refolding, we systematically identified that protein-chaperone interactions are key determinants of their protein functions at low temperatures. Furthermore, chromosomal gene deletion experiments suggest that the mechanism of cold-induced systems failure in E. coli is cold-induced inactivation of the GroELS chaperonins and the resulting failure to refold cold-inactivated Dps, ClpB, DnaK and RpsB proteins. These findings: (1) indicate the potential importance of chaperones in cold sensitivity, cold adaptation and cold tolerance in cellular systems, and (2) suggest the identity of a few key cold-sensitive chaperone-interacting proteins that get inactivated and ultimately cause systems failure in E. coli cells at low temperatures. 相似文献
1000.
Pessela BC Torres R Batalla P Fuentes M Mateo C Fernández-Lafuente R Guisán JM 《Biotechnology progress》2006,22(2):590-594
We have developed a new protocol with only two steps for purification of immunoglobulins (Ig) from a protein concentrate of whey. Following this protocol, we have an 80% recovery of immunoglobulins, fairly pure. The purification was achieved by eliminating the BSA, via a strong adsorption on DEAE-agarose. Full desoprtion of the other serum proteins could be achieved without contamination with BSA. Thus, a protein solution containing only Ig and very small proteins (e.g., beta-lactoglobulins and alpha-lactalbumin) was obtained. Offering this protein mixture to a lowly activated aminated support, only Ig adsorbed on the support. It has been shown that BSA is able to interact with other proteins (including Ig and lactalbumins). This ability to form complexes with other proteins prevented the success of the direct adsorption of Ig on this mildly activated support, even although Ig should be the largest protein presented in dairy whey. 相似文献