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排序方式: 共有162条查询结果,搜索用时 11 毫秒
41.
Bats account for 30% of mammal diversity in SE Asia and are potential bioindicators of wider biodiversity impacts resulting from habitat loss and climate change.As existing sampling techniques in the region typically fail to record bats that habitually fly in open areas and at higher altitudes,current inventory efforts are less than comprehensive.Acoustic sampling with bat detectors may help to overcome these limitations for insectivorous bats,but has yet to be tested in mainland SE Asia.To do so,we sampled... 相似文献
42.
Gitta Huth Otto Holst Jens Wohlmann Ulrike Becken Tobias Dykstra Kristina Söhl Buko Lindner John F. Prescott Ulrich E. Schaible Olaf Utermöhlen Albert Haas 《Cellular microbiology》2013,15(3):458-473
Rhodococcus equi is a close relative of Mycobacterium spp. and a facultative intracellular pathogen which arrests phagosome maturation in macrophages before the late endocytic stage. We have screened a transposon mutant library of R. equi for mutants with decreased capability to prevent phagolysosome formation. This screen yielded a mutant in the gene for β‐ketoacyl‐(acyl carrier protein)‐synthase A (KasA), a key enzyme of the long‐chain mycolic acid synthesizing FAS‐II system. The longest kasA mutant mycolic acid chains were 10 carbon units shorter than those of wild‐type bacteria. Coating of non‐pathogenic E. coli with purified wild‐type trehalose dimycolate reduced phagolysosome formation substantially which was not the case with shorter kasA mutant‐derived trehalose dimycolate. The mutant was moderately attenuated in macrophages and in a mouse infection model, but was fully cytotoxic.Whereas loss of KasA is lethal in mycobacteria, R. equi kasA mutant multiplication in broth was normal proving that long‐chain mycolic acid compounds are not necessarily required for cellular integrity and viability of the bacteria that typically produce them. This study demonstrates a central role of mycolic acid chain length in diversion of trafficking by R. equi. 相似文献
43.
Natalie S. Dykstra Lucie Hyde Alexander MacKenzie David R. Mack 《Probiotics and antimicrobial proteins》2011,3(1):21-26
Selective microbes used as probiotics can enhance epithelial cell protection. We have previously shown that a Lactobacillus plantarum strain 299v (Lp299v) has the ability to induce mucin genes. In the current study, we utilized a cytokine model of inflammation in cell culture to study the modulation of apoptosis by this probiotic. HT-29 cells were pre-incubated with the Lp299v or L. plantarum strain adh- (Lpadh-), a non-adherent derivative of Lp299v. Cells were challenged with a mixture of cytokines (TNF-α, IFN-γ, and IL-1a) to imitate conditions of inflammation. To assess for cell death, we evaluated TUNEL, multi-caspase, and caspase-3 and caspase-7 activity assays. There was a marked decrease in apoptosis as measured by TUNEL+ cells in samples pre-treated with Lp299v (18.7 ± 4.1%, p < 0.01) and Lpadh- (16.6 ± 3.2%, p < 0.05) prior to cytokine exposure when compared to cells (43.6 ± 6.2%) exposed to the cytokine mixture. Lp299v pre-incubation with HT-29 cells reduced caspase+ cells in the multi-caspase activity assay (3.6 ± 0.6%, p < 0.05) compared to cells exposed to cytokines (68.9 ± 5.1%) whereas Lpadh- did not (46.8 ± 17.5%, p > 0.05). Similarly, caspase-3, caspase-7 activity was also reduced by Lp299v. Selected probiotics may confer an exogenous protective effect at the mucosal–luminal interface for intestinal epithelial cells via alteration of caspase-dependent apoptotic pathways. 相似文献
44.
Serially presented tones are sometimes segregated into two perceptually distinct streams. An ongoing debate is whether this basic streaming phenomenon reflects automatic processes or requires attention focused to the stimuli. Here, we examined the influence of focused attention on streaming-related activity in human auditory cortex using magnetoencephalography (MEG). Listeners were presented with a dichotic paradigm in which left-ear stimuli consisted of canonical streaming stimuli (ABA_ or ABAA) and right-ear stimuli consisted of a classical oddball paradigm. In phase one, listeners were instructed to attend the right-ear oddball sequence and detect rare deviants. In phase two, they were instructed to attend the left ear streaming stimulus and report whether they heard one or two streams. The frequency difference (ΔF) of the sequences was set such that the smallest and largest ΔF conditions generally induced one- and two-stream percepts, respectively. Two intermediate ΔF conditions were chosen to elicit bistable percepts (i.e., either one or two streams). Attention enhanced the peak-to-peak amplitude of the P1-N1 complex, but only for ambiguous ΔF conditions, consistent with the notion that automatic mechanisms for streaming tightly interact with attention and that the latter is of particular importance for ambiguous sound sequences. 相似文献
45.
Shuwen He Zhong Lai Qingmei Hong Jackie Shang Mikhail Reibarkh Jeffrey T. Kuethe Jian Liu Deodial Guiadeen Arto D. Krikorian Timothy A. Cernak Kevin D. Dykstra Donald M. Sperbeck Zhicai Wu Yang Yu Ginger X. Yang Tianying Jian Andreas Verras Lisa M. Sonatore Robert J. DeVita 《Bioorganic & medicinal chemistry letters》2019,29(10):1182-1186
Previously disclosed benzimidazole-based DGAT1 inhibitors containing a cyclohexane carboxylic acid moiety suffer from isomerization at the alpha position of the carboxylic acid group, generating active metabolites which exhibit DGAT1 inhibition comparable to the corresponding parent compounds. In this report, we describe the design, synthesis and profiling of benzimidazole-based DGAT1 inhibitors with a [3.1.0] bicyclohexane carboxylic acid moiety. Our results show that single isomer 3A maintains in vitro and in vivo inhibition against DGAT1. In contrast to previous lead compounds, 3A does not undergo isomerization during in vitro hepatocyte incubation study or in vivo mouse study. 相似文献
46.
Tetraploid parenchymal rat liver nuclei incorporate about twice as much (3H)dexamethasone as diploid parenchymal nuclei both in vivo and in vitro. This suggests that the ability of hepatic nuclei to incorporate glucocorticoid hormone is influenced by the number of copies of the genome in these nuclei. 相似文献
47.
A genome survey of Moniliophthora perniciosa gives new insights into Witches' Broom Disease of cacao
Jorge MC Mondego Marcelo F Carazzolle Gustavo GL Costa Eduardo F Formighieri Lucas P Parizzi Johana Rincones Carolina Cotomacci Dirce M Carraro Anderson F Cunha Helaine Carrer Ramon O Vidal Raíssa C Estrela Odalys García Daniela PT Thomazella Bruno V de Oliveira Acássia BL Pires Carolina S Maria Rio Marcos Renato R Araújo Marcos H de Moraes Luis AB Castro Karina P Gramacho Marilda S Gonçalves José P Moura Neto Aristóteles Góes Neto Luciana V Barbosa Mark J Guiltinan Bryan A Bailey Lyndel W Meinhardt Julio CM Cascardo Gonçalo AG Pereira 《BMC genomics》2008,9(1):1-25
48.
Heidi A. Crosby Nitija Tiwari Jakub M. Kwiecinski Zhen Xu Allison Dykstra Christian Jenul Ernesto J. Fuentes Alexander R. Horswill 《Molecular microbiology》2020,113(1):103-122
The Gram-positive bacterium, Staphylococcus aureus, is a versatile pathogen that can sense and adapt to a wide variety of environments within the human host, in part through its 16 two-component regulatory systems. The ArlRS two-component system has been shown to affect many cellular processes in S. aureus, including autolysis, biofilm formation, capsule synthesis and virulence. Yet the molecular details of this regulation remained largely unknown. We used RNA sequencing to identify the ArlRS regulon, and found 70% overlap with that of the global regulator MgrA. These genes included cell wall-anchored adhesins (ebh, sdrD), polysaccharide and capsule synthesis genes, cell wall remodeling genes (lytN, ddh), the urease operon, genes involved in metal transport (feoA, mntH, sirA), anaerobic metabolism genes (adhE, pflA, nrdDG) and a large number of virulence factors (lukSF, lukAB, nuc, gehB, norB, chs, scn and esxA). We show that ArlR directly activates expression of mgrA and identify a probable ArlR-binding site (TTTTCTCAT-N4-TTTTAATAA). A highly similar sequence is also found in the spx P2 promoter, which was recently shown to be regulated by ArlRS. We also demonstrate that ArlS has kinase activity toward ArlR in vitro, although it has slower kinetics than other similar histidine kinases. 相似文献
49.
50.
IB Masters MM Eastburn PW Francis R Wootton PV Zimmerman RS Ware AB Chang 《Respiratory research》2005,6(1):16