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41.
Capturing and marking free‐living birds permits the study of important aspects of their biology but may have undesirable effects. Bird welfare should be a primary concern, so it is necessary to evaluate and minimize any adverse effects of procedures used. We assess short‐term effects associated with the capture, handling and tagging with backpack‐mounted transmitters of Pin‐tailed Pterocles alchata and Black‐bellied Pterocles orientalis Sandgrouse, steppe birds of conservation concern. There was a significantly higher mortality (15%) during the first week after capture than during the following weeks (< 2.5%) in Pin‐tailed Sandgrouse, but no significant temporal mortality pattern in Black‐bellied Sandgrouse. In Pin‐tailed Sandgrouse, mortality rate during the first week increased with increasing relative transmitter and harness weight regardless of season, and with increasing handling time during the breeding season. There were no significant differences in mortality rate between study areas, type of tag, sex or age or an effect of restraint time. These results suggest the use of lighter transmitters (< 3% of the bird's weight) and a reduction of handling time (< 20 min), particularly during the breeding season, as essential improvements in procedure to reduce the mortality risk associated with the capture, handling and tagging of these vulnerable species.  相似文献   
42.
Evidence is mounting that the occurrence of the CD44pos/CD24neg/low cell population, which contains potential breast cancer (BC) stem cells, could explain BC clinical resistance to HER2-targeted therapies. We investigated whether de novo refractoriness to the anti-HER2 monoclonal antibody trastuzumab (Tzb; Herceptin) may relate to the dynamic regulation of the mesenchymal CD44pos/CD24neg/low phenotype in HER2-positive BC. We observed that the subpopulation of Tzb-refractory JIMT-1 BC cells exhibiting CD44pos/CD24neg/low-surface markers switched with time. Low-passage JIMT-1 cell cultures were found to spontaneously contain ∼10% of cells bearing the CD44pos/CD24neg/low immunophenotype. Late-passage (>60) JIMT-1 cultures accumulated ∼80% of CD44pos/CD24neg/low cells and closely resembled the CD44pos/CD24neg/low-enriched (∼85%) cell population constitutively occurring in HER2-negative MDA-MB-231 mesenchymal BC cells. Dynamic expression of mesenchymal markers was not limited to CD44/CD24 because high-passages of JIMT-1 cells exhibited also reduced expression of the HER2 protein and over-secretion of pro-invasive/metastatic chemokines and metalloproteases. Accordingly, late-passage JIMT-1 cells displayed an exacerbated migratogenic phenotype in plastic, collagen, and fibronectin substrates. Intrinsic genetic plasticity to efficiently drive the emergence of the CD44pos/CD24neg/low mesenchymal phenotype may account for de novo resistance to HER2 targeting therapies in basal-like BC carrying HER2 gene amplification.  相似文献   
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Metallo-beta-lactamases (MbetaLs) are zinc-dependent enzymes able to hydrolyze and inactivate most beta-lactam antibiotics. The large diversity of active site structures and metal content among MbetaLs from different sources has limited the design of a pan-MbetaL inhibitor. Here we report the biochemical and biophysical characterization of a novel MbetaL, GOB-18, from a clinical isolate of a Gram-negative opportunistic pathogen, Elizabethkingia meningoseptica. Different spectroscopic techniques, three-dimensional modeling, and mutagenesis experiments, reveal that the Zn(II) ion is bound to Asp120, His121, His263, and a solvent molecule, i.e. in the canonical Zn2 site of dinuclear MbetaLs. Contrasting all other related MbetaLs, GOB-18 is fully active against a broad range of beta-lactam substrates using a single Zn(II) ion in this site. These data further enlarge the structural diversity of MbetaLs.  相似文献   
45.
Motivation: DNA microarrays are a well-known and established technology in biological and pharmaceutical research providing a wealth of information essential for understanding biological processes and aiding drug development. Protein microarrays are quickly emerging as a follow-up technology, which will also begin to experience rapid growth as the challenges in protein to spot methodologies are overcome. Like DNA microarrays, their protein counterparts produce large amounts of data that must be suitably analyzed in order to yield meaningful information that should eventually lead to novel drug targets and biomarkers. Although the statistical management of DNA microarray data has been well described, there is no available report that offers a successful consolidated approach to the analysis of high-throughput protein microarray data. We describe the novel application of a statistical methodology to analyze the data from an immune response profiling assay using human protein microarray with over 5000 proteins on each chip.  相似文献   
46.
Lycopersicon esculentum plants exhibit increased salt stress tolerance following treatment with adipic acid monoethylester and 1,3-diaminepropane (DAAME), known as an inducer of resistance against biotic stress in tomato and pepper. For an efficient water and nutrient uptake, plants should adapt their water potential to compensate a decrease in water soil potential produced by salt stress. DAAME-treated plants showed a faster and stronger water potential reduction and an enhanced proline accumulation. Salinity-induced oxidative stress was also ameliorated by DAAME treatments. Oxidative membrane damage and ethylene emission were both reduced in DAAME-treated plants. This effect is probably a consequence of an increase of both non-enzymatic antioxidant activity as well as peroxidase activity. DAAME-mediated tolerance resulted in an unaltered photosynthetic rate and a stimulation of the decrease in transpiration under stress conditions without a cost in growth due to salt stress. The reduction in transpiration rate was concomitant with a reduction in phytotoxic Na+ and Cl accumulation under saline stress. Interestingly, the ABA deficient tomato mutant sitiens was insensitive to DAAME-induced tolerance following NaCl stress exposure. Additionally, DAAME treatments increased the ABA content of leaves, therefore, an intact ABA signalling pathway seems to be important to express DAAME-induced salt tolerance. Here, we show a possibility of enhance tomato stress tolerance by chemical induction of the major plant defences against salt stress. DAAME-induced tolerance against salt stress could be complementary to or share elements with induced resistance against biotic stress. This might be the reason for the observed wide spectrum of effectiveness of this compound.Key Words: adipic acid monoethyl ester, 1,3-diaminepropane, Lycopersicon esculentum, salt stress, oxidative stress, ethylene, chemical induced tolerance  相似文献   
47.
48.
Activation of naive CD8 T cells in vivo requires the recognition of cognate peptide-MHC complexes on APCs. Depending upon the activation status of the APC, such recognition will promote either a vigorous immune response or T cell tolerance and deletion. Recent studies suggest that the initial signals provided by APCs are sufficient to program the proliferation of naive CD8 T cells and their differentiation into effector cells. In this study, we sought to determine whether an initial encounter with tolerogenic APCs was sufficient to program deletion of naive CD8 T cells. Surprisingly, we find that regardless of whether naive CD8 T cells were stimulated by activated or quiescent APCs, transfer of the activated T cells into an Ag-free host was sufficient to ensure survival. Thus, although the extent of clonal expansion and development of effector function is determined by the activation status of the stimulatory APC, peripheral clonal deletion requires persistent Ag and is not determined by the initial stimulatory event.  相似文献   
49.
Javier Miragaya 《Steroids》2009,74(9):735-361
A norbornyl-2-acetyl derivative of cholic acid ([3β,5β,7α,12α]-3[(norbornyl-2-acetyl)-amino]-7,12-dihydroxycholan-24-oic acid -NbCH2CA-) was synthesized and recrystallized in two dipolar aprotic solvents (acetone, DMSO) and in one protic solvent (2-propanol). In DMSO and acetone the crystals are orthorhombic, P212121 (all their parameters being very similar) while in 2-propanol the crystal is monoclinic, P21. The inclusion complexes with the solvent have a 1:1 stochiometry with DMSO and acetone and 1:2 with 2-propanol. All solvents are forming a hydrogen bond with the amide bond of the bridge between the norbornyl residue and the steroid nucleus of the bile acid. In DMSO and acetone the β side of the steroid groups lies in the same region facilitating hydrophobic interactions, and the molecules are disposed in an antiparallel orientation (the methyl groups having a β interdigitation) forming bilayers. The width of the bilayers is 9.231 Å and 8.859 Å in DMSO and acetone, respectively. A lamellar structure is also evident for the crystal in 2-propanol (the width being 11.908 Å), but the packing is different from the previous one since a sliding between the steroid groups is observed and the methyl groups are not interdigitated. Four different hydrogen bonds are established by every steroid molecule in the NbCH2CA/DMSO (or acetone) crystal. This hydrogen bond network interconnects the hydrophilic regions of the lamellar structure. The hydrogen bond network of the NbCH2CA:2-propanol crystal is different because of the different abilities of 2-propanol to form hydrogen bonds. The side chain has a ttti conformation in the two orthorhombic crystals, and a tgtg one in the monoclinic crystal.  相似文献   
50.
Naccobus aberrans is a major pest of the potato crop in the Andean regions of Argentina, Bolivia, and Perú. It is endemic in northwest Argentina and is also found in lowlands. The resistance of eleven Andean potato landraces and three accessions of the wild tuber-bearing species Solanum acaule, S. infundibuliforme, and S. megistacrolobum were evaluated against a population of N. aberrans from Coctaca, Jujuy province, while Solanum tuberosum ssp. tuberosum 'Spunta', 'Kennebec', and 'Frital INTA' were evaluated against a population from the southeast of Buenos Aires province. The presence, the number of galls, and the number of individuals were recorded. In addition, a reproduction factor was calculated and races were determined. Results showed that the N. aberrans population from Coctaca corresponded to race 2 and the population from the lowlands belonged to the sugar beet group. Landrace Azul, one genotype of S. megistacrolobum, and two genotypes of S. acaule showed resistance towards the race from Coctaca while no infection was recorded in potato cultivars with the Naccobus race from the lowland area.  相似文献   
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