排序方式: 共有166条查询结果,搜索用时 31 毫秒
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Loss of function of Arabidopsis NADP‐malic enzyme 1 results in enhanced tolerance to aluminum stress
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álvaro Menin Renata Fleith Carolina Reck Mariel Marlow Paula Fernandes Célso Pilati André Báfica 《PloS one》2013,8(1)
Rational discovery of novel immunodiagnostic and vaccine candidate antigens to control bovine tuberculosis (bTB) requires knowledge of disease immunopathogenesis. However, there remains a paucity of information on the Mycobacterium bovis-host immune interactions during the natural infection. Analysis of 247 naturally PPD+ M. bovis-infected cattle revealed that 92% (n = 228) of these animals were found to display no clinical signs, but presented severe as well as disseminated bTB-lesions at post-mortem examination. Moreover, dissemination of bTB-lesions positively correlated with both pathology severity score (Spearman r = 0.48; p<0.0001) and viable tissue bacterial loads (Spearman r = 0.58; p = 0.0001). Additionally, granuloma encapsulation negatively correlated with M. bovis growth as well as pathology severity, suggesting that encapsulation is an effective mechanism to control bacterial proliferation during natural infection. Moreover, multinucleated giant cell numbers were found to negatively correlate with bacterial counts (Spearman r = 0.25; p = 0.03) in lung granulomas. In contrast, neutrophil numbers in the granuloma were associated with increased M. bovis proliferation (Spearman r = 0.27; p = 0.021). Together, our findings suggest that encapsulation and multinucleated giant cells control M. bovis viability, whereas neutrophils may serve as a cellular biomarker of bacterial proliferation during natural infection. These data integrate host granuloma responses with mycobacterial dissemination and could provide useful immunopathological-based biomarkers of disease severity in natural infection with M. bovis, an important cattle pathogen. 相似文献
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Katarzyna Garbacz Sabina Żarnowska Lidia Piechowicz Krystyna Haras 《Current microbiology》2013,66(2):169-173
The aim of this study was to compare the spread of multidrug-resistant (MDR) and methicillin-resistant (MR) staphylococci in healthy dogs and in dogs with evident symptoms of infection. The samples from 172 healthy and 197 infected dogs were examined. The staphylococci were identified with conventional methods and by means of the polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) method (MboI). Susceptibility to 15 antibiotics from 10 different antimicrobial classes was tested. Resistance to methicillin was confirmed by the presence of Staphylococcus aureus mecA and S. sciuri mecA genes. Multidrug resistance was defined as resistance to three or more antimicrobial classes. The oral mucosa to be the most frequent site of staphylococcal colonization (55.8 %), followed by nasal cavity (44.2 %), and anus (32.6 %). The prevalence of MDR staphylococci in infected dogs was significantly higher than in the healthy animals (74/137 vs. 34/95, P = 0.006). The MR strains of S. pseudintermedius (2.9 %) originated solely from infected dogs. In contrast, the MR coagulase-negative strains (7.4 %) were isolated solely from healthy dogs. S. aureus strains originated from nasal swabs, MRSA strains were not isolated. MDR staphylococci and MR S. pseudintermedius are more common among infected dogs, but coagulase-negative staphylococci (mostly S. sciuri) seem to be a reservoir of methicillin resistance in healthy dogs. 相似文献
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Joshua Ladau Thomas J Sharpton Mariel M Finucane Guillaume Jospin Steven W Kembel James O'Dwyer Alexander F Koeppel Jessica L Green Katherine S Pollard 《The ISME journal》2013,7(9):1669-1677
Genomic approaches to characterizing bacterial communities are revealing significant differences in diversity and composition between environments. But bacterial distributions have not been mapped at a global scale. Although current community surveys are way too sparse to map global diversity patterns directly, there is now sufficient data to fit accurate models of how bacterial distributions vary across different environments and to make global scale maps from these models. We apply this approach to map the global distributions of bacteria in marine surface waters. Our spatially and temporally explicit predictions suggest that bacterial diversity peaks in temperate latitudes across the world''s oceans. These global peaks are seasonal, occurring 6 months apart in the two hemispheres, in the boreal and austral winters. This pattern is quite different from the tropical, seasonally consistent diversity patterns observed for most macroorganisms. However, like other marine organisms, surface water bacteria are particularly diverse in regions of high human environmental impacts on the oceans. Our maps provide the first picture of bacterial distributions at a global scale and suggest important differences between the diversity patterns of bacteria compared with other organisms. 相似文献
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Jos Antonio García-Espinoza Jos Francisco Muoz-Valle Mariel García-Chagolln Jorge Hernndez-Bello Claudia Azucena Palafox-Snchez Erika Fabiola Lpez-Villalobos Gabriela Athziri Snchez-Zuno Gloria Esther Martínez-Bonilla Sergio Cerpa-Cruz Francisco Josue Carrillo-Ballesteros Edith Oregon-Romero 《Current issues in molecular biology》2022,44(2):764
Background: Primary Sjögren’s syndrome (pSS) is a systemic autoimmune disease, which affects exocrine glands. T cell activation is a trigger mechanism in the immune response. Hyperreactivity of T cells and antibody production are features in pSS. ICOS can be critical in the pathogenesis of pSS. Methods: A total of 134 pSS patients and 134 control subjects (CS) were included. Genotyping was performed by PCR-RFLP. ICOS mRNA expression was quantified by real-time PCR, and CD4+ ICOS+ T cells were determined by flow cytometry. Results: The ICOS IVS1 + 173 T>C polymorphisms were not associated with susceptibility to pSS (p = 0.393, CI = 0.503–1.311). However, the c.1624 C>T polymorphism was associated with a reduction in the risk of development of pSS (p = 0.015, CI = 0.294–0.884). An increase in ICOS mRNA expression in patients was observed (3.7-fold). Furthermore, pSS patients showed an increase in membranal-ICOS expression (mICOS). High expression of mICOS (MFI) was associated with lymphocytic infiltration. Conclusions: The IVS1 + 173 polymorphism is not a genetic marker for the development of pSS, while c.1624 T allele was associated with a low risk. However, elevated mICOS expression in pSS patients with high lymphocytic infiltration was found. ICOS may have an important role in the immunopathogenesis of pSS and should be analyzed in T cell subsets in pSS patients as a possible disease marker. 相似文献
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Detarsio E Wheeler MC Campos Bermúdez VA Andreo CS Drincovich MF 《The Journal of biological chemistry》2003,278(16):13757-13764
Malic enzymes catalyze the oxidative decarboxylation of l-malate to yield pyruvate, CO(2), and NAD(P)H in the presence of a bivalent metal ion. In plants, different isoforms of the NADP-malic enzyme (NADP-ME) are involved in a wide range of metabolic pathways. The C(4)-specific NADP-ME has evolved from C(3)-type malic enzymes to represent a unique and specialized form of NADP-ME as indicated by its particular kinetic and regulatory properties. In the present study, the mature C(4)-specific NADP-ME of maize was expressed in Escherichia coli. The recombinant enzyme has essentially the same physicochemical properties and K(m) for the substrates as those of the naturally occurring NADP-ME previously characterized. However, the k(cat) was almost 7-fold higher, which may suggest that the previously purified enzyme from maize leaves was partially inactive. The recombinant NADP-ME also has a very low intrinsic NAD-dependent activity. Five mutants of NADP-ME at the postulated putative NADP-binding site(s) (Gsite5V, Gsite2V, A392G, A387G, and R237L) were constructed by site-directed mutagenesis and purified to homogeneity. The participation of these residues in substrate binding and/or the catalytic reaction was inferred by kinetic measurements and circular dichroism and intrinsic fluorescence spectra. The results obtained were compared with a predicted three-dimensional model of maize C(4) NADP-ME based on crystallographic studies of related animal NAD(P)-MEs. The data presented here represent the first prokaryotic expression of a plant NADP-ME and reveals valuable insight regarding the participation of the mutated amino acids in the binding of substrates and/or catalysis. 相似文献
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TangleSolve is a program for analysing site-specific recombination using the tangle model. The program offers an easy-to-use graphical user interface and a visualization tool. Biologists working in topological enzymology can use this program to compute and visualize site-specific recombination mechanisms that accommodate their experimental data. TangleSolve can also prove useful as a teaching aid for mathematical biology and computational molecular biology courses. AVAILABILITY: http://bio.math.berkeley.edu/TangleSolve/ 相似文献
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