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91.
Ching-Tsun Chang Wei-Chuan Chiang Yun-Chen Chang Michael K. Musyl Chi-Lu Sun Daniel J. Madigan Aaron B. Carlisle Hung-Hung Hsu Qi-Xuan Chang Nan-Jay Su Yuan-Shing Ho Chen-Te Tseng 《Journal of fish biology》2019,94(6):958-965
To gain a better understanding of the trophic ecology of Pacific blue marlin Makaira nigricans off eastern Taiwan, nitrogen and carbon stable isotopes (δ15N and δ13C) and Bayesian mixing models were used to explore trophic dynamics and potential ontogenetic feeding shifts across M. nigricans of different size classes. Makaira nigricans samples from east of Taiwan (n = 213) and Palau (n = 37), as well as their prey (n = 70), were collected during 2012 and 2013. Results indicated increases in δ15N with size, with values of larger size classes (> 200 cm eye-to-fork length; LEF) significantly higher than those < 200 cm LEF. Values of δ13C were negatively correlated with size. Makaira nigricans > 200 cm LEF had the highest estimated trophic position (4.44) and also exhibited ontogenetic changes in trophic position. Large M. nigricans fed more on dolphinfish Coryphaena hippurus and hairtail Trichiurus lepturus, while smaller M. nigricans consumed smaller forage fish (e.g., moonfish Mene maculata) and cephalopods. These changes may relate to greater swimming speeds and vertical habitat use in larger M. nigricans, allowing capture and consumption of larger prey items at higher trophic positions. The high trophic level of M. nigricans east of Taiwan confirms its important role as an apex predator in marine food webs and how ecological role changes with size. 相似文献
92.
Crosslinking CD81 results in activation of TCRgammadelta T cells 总被引:1,自引:0,他引:1
CD81 is expressed on most cells and is associated with other glycoproteins, including CD4 and CD8, to form multimolecular membrane complexes. Crosslinking of CD81 on TCRalphabeta(+) T cells results in costimulatory signals that have been proposed to be mediated via CD4 or CD8. In this study, we show that CD81 is also expressed on TCRgammadelta(+)CD4(-)CD8(-) T cells. CD81 crosslinking greatly enhanced anti-CD3 activation of both TCRalphabeta(+) (CD4+ and CD8+) and TCRgammadelta(+) T cells with regard to IFN-gamma production. However, crosslinking of CD81 molecules on TCRgammadelta(+) T cells, in the absence of anti-CD3 stimulation, resulted in cytokine production and enhanced IL-2-induced proliferation, demonstrating that physical association with CD4 or CD8 is not necessary for CD81 signaling. In contrast, crosslinking of CD81 on TCRalphabeta(+) T cells, in the absence of anti-CD3 stimulation, failed to activate these T cells. These results suggest that CD81 signaling may be mediated via a different mechanism(s) in TCRgammadelta(+) versus TCRalphabeta(+) T cells. 相似文献
93.
DNA cloning without restriction enzyme and ligase 总被引:1,自引:0,他引:1
Tseng H 《BioTechniques》1999,27(6):1240-1244
One common problem in using the traditional DNA cloning procedure is that suitable natural restriction sites are often unavailable for a given task. Creating new restriction sites is often time consuming. Here, I describe a simple technique of producing "customized cohesive ends" by a combination of PCR primer design and lambda exonuclease digestion. These complementary cohesive ends can form hybrids to link two sequences. Because the overhangs created by lambda exonuclease are slightly longer than the complementary sequence, after hybrid formation, a stretch of single-strand gap remains, which then is repaired by Klenow (3'-->5' exo-) enzyme. The repair process also stabilizes the linkage. Because of the independence from natural or artificial restriction sites, this method allows rapid and precise insertion of one DNA fragment into another at virtually any position. It also simplifies the planning of a cloning strategy, increases recombinant frequency and is suitable for automation. 相似文献
94.
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96.
Qiu YL Sekiguchi Y Imachi H Kamagata Y Tseng IC Cheng SS Ohashi A Harada H 《Applied and environmental microbiology》2004,70(3):1617-1626
The microbial populations responsible for anaerobic degradation of phthalate isomers were investigated by enrichment and isolation of those microbes from anaerobic sludge treating wastewater from the manufacturing of terephthalic acid. Primary enrichments were made with each of three phthalate isomers (ortho-, iso-, and terephthalate) as the sole energy source at 37 degrees C with two sources of anaerobic sludge (both had been used to treat wastewater containing high concentrations of phthalate isomers) as the inoculum. Six methanogenic enrichment cultures were obtained which not only degraded the isomer used for the enrichment but also had the potential to degrade part of other phthalate isomers as well as benzoate with concomitant production of methane, presumably involving strictly syntrophic substrate degradation. Our 16S rRNA gene-cloning analysis combined with fluorescence in situ hybridization revealed that the predominant bacteria in the enrichment cultures were affiliated with a recently recognized non-sulfate-reducing subcluster (subcluster Ih) in the group 'Desulfotomaculum lineage I' or a clone cluster (group TA) in the class delta-PROTEOBACTERIA: Several attempts were made to isolate these microbes, resulting in the isolation of a terephthalate-degrading bacterium, designated strain JT, in pure culture. A coculture of the strain with the hydrogenotrophic methanogen Methanospirillum hungatei converted terephthalate to acetate and methane within 3 months of incubation, whereas strain JT could not degrade terephthalate in pure culture. During the degradation of terephthalate, a small amount of benzoate was transiently accumulated as an intermediate, indicative of decarboxylation of terephthalate to benzoate as the initial step of the degradation. 16S rRNA gene sequence analysis revealed that the strain was a member of subcluster Ih of the group 'Desulfotomaculum lineage I', but it was only distantly related to other known species. 相似文献
97.
Hsu PI Li CN Tseng HH Lai KH Hsu PN Lo GH Lo CC Yeh JJ Ger LP Hsiao M Yamaoka Y Hwang IR Chen A 《Helicobacter》2004,9(6):605-613
BACKGROUND: The host genetic factors that determine the clinical outcomes for Helicobacter pylori-infected individuals remain unclear. AIMS: To elucidate the relations among interleukin-1 locus polymorphisms, and H. pylori infection in the development of duodenal ulcers. MATERIALS AND METHODS: In a case-control study involving 168 control subjects and 147 patients with duodenal ulcer, biallelic polymorphisms of two interleukin-1 loci, IL-1B(-511) and IL-1B(+3954), as well as the penta-allelic variable number of tandem repeats of interleukin-1 receptor antagonist IL-1RN, were genotyped, and the H. pylori states of controls and patients were examined. RESULTS: Helicobacter pylori infection, male gender and the carriage of IL-1RN*2 independently increased the risk of duodenal ulcer with odds ratios of 6.4 (95% confidence interval, 3.7-11.0), 1.9 (95% confidence interval, 1.1-3.4) and 2.7 (95% confidence interval, 1.1-6.8), respectively. Statistical analysis revealed an interaction between IL-1RN*2 and H. pylori infection with the duodenal ulcer risk conferred by the H. pylori infection substantially increased (odds ratios, 22.6; 95% confidence interval, 5.9-86.5) by the carriage of IL-1RN*2. In addition, a synergistic interaction between IL-1RN*2 and blood group O existed. The combined risk of H. pylori infection, the carriage of IL-1RN*2 and blood group O for duodenal ulcer was 27.5 (95% confidence interval, 3.1-243.6). CONCLUSIONS: This work is the first to verify IL-1RN*2 as an independent factor that governs the development of duodenal ulcers. Our data indicate that H. pylori infection and IL-1RN*2 synergistically determine susceptibility to duodenal ulcer. The blood group phenotype is possibly a crucial determinant for the outcome of the impact of an interleukin-1 locus polymorphism on H. pylori-infected individuals. 相似文献
98.
Rho kinase regulates the intracellular micromechanical response of adherent cells to rho activation 总被引:5,自引:0,他引:5
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Local sol-gel transitions of the cytoskeleton modulate cell shape changes, which are required for essential cellular functions, including motility and adhesion. In vitro studies using purified cytoskeletal proteins have suggested molecular mechanisms of regulation of cytoskeleton mechanics; however, the mechanical behavior of living cells and the signaling pathways by which it is regulated remains largely unknown. To address this issue, we used a nanoscale sensing method, intracellular microrheology, to examine the mechanical response of the cell to activation of the small GTPase Rho. We observe that the cytoplasmic stiffness and viscosity of serum-starved Swiss 3T3 cells transiently and locally enhances upon treatment with lysophosphatidic acid, and this mechanical behavior follows a trend similar to Rho activity. Furthermore, the time-dependent activation of Rho decreases the degree of microheterogeneity of the cytoplasm. Our results reveal fundamental differences between intracellular elasticity and cellular tension and suggest a critical role for Rho kinase in the regulation of intracellular mechanics. 相似文献
99.
Qiu YL Sekiguchi Y Imachi H Kamagata Y Tseng IC Cheng SS Ohashi A Harada H 《Archives of microbiology》2003,179(4):242-249
An anaerobic, mesophilic, syntrophic benzoate-degrading bacterium, designated strain FB(T), was isolated from methanogenic sludge which had been used to treat wastewater from the manufacture of terephthalic acid. Cells were non-motile gram-positive rods that formed spores. The optimum temperature for growth was 35-40 degrees C, and the optimum pH was 7.0-7.2. A co-culture with the hydrogenotrophic methanogen Methanospirillum hungatei converted benzoate to acetate, carbon dioxide, and methane. Butyrate transiently accumulated at a high concentration of 2.5 mM during degradation. Besides benzoate, no other compound tested supported growth of the co-culture. Crotonate supported growth of strain FB(T) in pure culture. Furthermore, the strain degraded benzoate in pure culture with crotonate as co-substrate to produce acetate and butyrate. The strain was not able to utilize sulfate, sulfite, thiosulfate, nitrate, fumarate, or Fe(III) as electron acceptor. The G+C content of the DNA was 46.8 mol%. Strain FB(T) contained MK-7 as the major quinone and C(16:1) as the major fatty acid. 16S rDNA sequence analysis revealed that the strain was a member of the genus Sporotomaculum, even though it exhibited significant differences, such as the capacity for syntrophic growth, to the known member of the genus. Hence, we propose the name Sporotomaculum syntrophicum sp. nov. for strain FB(T). The type strain is strain FB(T) (DSM 14795, JCM 11475). 相似文献
100.
Bcl-xL mediates a survival mechanism independent of the phosphoinositide 3-kinase/Akt pathway in prostate cancer cells 总被引:4,自引:0,他引:4
Yang CC Lin HP Chen CS Yang YT Tseng PH Rangnekar VM Chen CS 《The Journal of biological chemistry》2003,278(28):25872-25878
Among various molecular strategies by which prostate cancer cells evade apoptosis, phosphoinositide 3-kinase (PI3K)/Akt signaling represents a dominant survival pathway. However, different prostate cancer cell lines such as LNCaP and PC-3 display differential sensitivity to the apoptotic effect of PI3K inhibition in serum-free media, reflecting the heterogeneous nature of prostate cancer in apoptosis regulation. Whereas both cell lines are equally susceptible to LY294002-mediated Akt dephosphorylation, only LNCaP cells default to apoptosis, as evidenced by DNA fragmentation and cytochrome c release. In PC-3 cells, Akt deactivation does not lead to cytochrome c release, suggesting that the intermediary signaling pathway is short-circuited by an antiapoptotic factor. This study presents evidence that Bcl-xL overexpression provides a distinct survival mechanism that protects PC-3 cells from apoptotic signals emanating from PI3K inhibition. First, the Bcl-xL/BAD ratio in PC-3 cells is at least an order of magnitude greater than that of LNCaP cells. Second, ectopic expression of Bcl-xL protects LNCaP cells against LY294002-induced apoptosis. Third, antisense down-regulation of Bcl-xL sensitizes PC-3 cells to the apoptotic effect of LY294002. The physiological relevance of this Bcl-xL-mediated survival mechanism is further underscored by the protective effect of serum on LY294002-induced cell death in LNCaP cells, which is correlated with a multifold increase in Bcl-xL expression. In contrast to Bcl-xL, Bcl-2 expression levels are similar in both cells lines, and do not respond to serum stimulation, suggesting that Bcl-2 may not play a physiological role in antagonizing apoptosis signals pertinent to BAD activation in prostate cancer cells. 相似文献