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61.
Kogut MH Swaggerty C He H Pevzner I Kaiser P 《Microbes and infection / Institut Pasteur》2006,8(7):1866-1874
62.
The nature of bombesin-like immunoreactive peptides was studied in extracts of small cell carcinoma of the human lung. Three peaks, I, II and III, designated by their increasing retention times, were separated by reversed-phase high performance liquid chromatography (HPLC) with trifluoroacetic acid (TFA) as counter ion. None of the peaks corresponded to bombesin. Peak III was eluted at the same position as porcine gastrin releasing peptide (GRP) but was separated from it in another reversed-phase system using heptafluorobutyric acid (HFBA). Peak II material eluted in the position of bombesin in the HFBA system but not in the TFA system. The elution position of Peak I corresponded to that of the carboxyl terminal fragments of GRP, i.e. GRP18-27 and GRP19-27. This correspondence was observed in each of the reversed-phase and gel filtration systems used. The Peak III peptide was converted to peak I after incubation with trypsin. It was reasoned that this conversion could be one of the steps in the processing of bombesin-like peptides in human small cell carcinoma. 相似文献
63.
The genetically-engineeredEscherichia coli strain, DPD2540, which contains afabA::luxCDABE fusion gene, gives a bioluminescent output when membrane fatty acid synthesis is needed. For more practical application of
this strain in the field as biosensor, freeze-drying was adopted. A 12% sucrose solution with Luria-Bertani (LB) broth, as
determined by the viability after freeze-drying, was found to be the most effective composition for lyophilization solution
among various compositions tested. Rapid freezing with liquid nitrogen also gave the best viability after freeze-drying as
compared to samples frozen at −70°C and −20°C. The biosensing activities of the cells showed a greater sensitivity when the
cells from the exponential phase were freeze-dried. Finally, the optimum temperature for use of the freeze-dried cells in
the biosensor field was determined. 相似文献
64.
65.
Magdalena A. Gutowska F. Melzner M. Langenbuch C. Bock G. Claireaux H. O. Pörtner 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2010,180(3):323-335
Acidification of ocean surface waters by anthropogenic carbon dioxide (CO2) emissions is a currently developing scenario that warrants a broadening of research foci in the study of acid–base physiology.
Recent studies working with environmentally relevant CO2 levels, indicate that some echinoderms and molluscs reduce metabolic rates, soft tissue growth and calcification during hypercapnic
exposure. In contrast to all prior invertebrate species studied so far, growth trials with the cuttlefish Sepia officinalis found no indication of reduced growth or calcification performance during long-term exposure to 0.6 kPa CO2. It is hypothesized that the differing sensitivities to elevated seawater pCO2 could be explained by taxa specific differences in acid–base regulatory capacity. In this study, we examined the acid–base
regulatory ability of S. officinalis in vivo, using a specially modified cannulation technique as well as 31P NMR spectroscopy. During acute exposure to 0.6 kPa CO2, S. officinalis rapidly increased its blood [HCO3
−] to 10.4 mM through active ion-transport processes, and partially compensated the hypercapnia induced respiratory acidosis.
A minor decrease in intracellular pH (pHi) and stable intracellular phosphagen levels indicated efficient pHi regulation. We conclude that S. officinalis is not only an efficient acid–base regulator, but is also able to do so without disturbing metabolic equilibria in characteristic
tissues or compromising aerobic capacities. The cuttlefish did not exhibit acute intolerance to hypercapnia that has been
hypothesized for more active cephalopod species (squid). Even though blood pH (pHe) remained 0.18 pH units below control values,
arterial O2 saturation was not compromised in S. officinalis because of the comparatively lower pH sensitivity of oxygen binding to its blood pigment. This raises questions concerning
the potentially broad range of sensitivity to changes in acid–base status amongst invertebrates, as well as to the underlying
mechanistic origins. Further studies are needed to better characterize the connection between acid–base status and animal
fitness in various marine species. 相似文献
66.
The signaling processes that maintain the homeostatic proliferation of peripheral T-cells and result in their self-renewal largely remain to be elucidated. Much focus has been placed on the anti-apoptotic function of the cytokine, interleukin-7 (IL-7), during T-cell development. But a more critical role has been ascribed to IL-7 as a mediator of peripheral T-cell maintenance. The biological effects responsive to IL-7 signaling are transduced through only a few well-known pathways. In this review we will focus on the signals transduced by IL-7 and similar cytokines, examining how proliferative signals originate from cytokine receptors, are amplified and eventually alter gene expression. In this regard we will highlight the crosstalk between pathways that promote survival, drive cell cycle progression and most importantly provide the needed energy to sustain these critical cellular activities. Though this review showcases much of what has been learned about IL-7 proliferative signaling, it also reveals the significant gaps in our knowledge about cytokine signaling in the very relevant context of peripheral T-cell homeostasis. 相似文献
67.
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69.
Intrapopulation foraging niche variation between phenotypes and genotypes of Spirit bear populations
Christina N. Service Travis Ingram Thomas E. Reimchen Chris T. Darimont 《Ecology and evolution》2021,11(10):5025
Foraging niche variation within a species can contribute to the maintenance of phenotypic diversity. The multiniche model posits that phenotypes occupying different niches can contribute to the maintenance of balanced polymorphisms. Using coastal populations of black bears (Ursus americanus kermodei) from British Columbia, Canada, we examined potential foraging niche divergence between phenotypes (black and white “Spirit” coat color) and between genotypes (black‐coated homozygote and heterozygous). We applied the Bayesian multivariate models, with biotracers of diet (δ13C and δ15N) together comprising the response variable, to draw inference about foraging niche variation. Variance–covariance matrices from multivariate linear mixed‐effect models were visualized as the Bayesian standard ellipses in δ13C and δ15N isotopic space to assess potential seasonal and annual niche variation between phenotypes and genotypes. We did not detect a difference in annual isotopic foraging niche area in comparisons between genotypes or phenotypes. Consistent with previous field experimental and isotopic analyses, however, we found that white phenotype Spirit bears were modestly more enriched in δ15N during the fall foraging season, though with our modest sample sizes these results were not significant. Although also not statistically significant, variation in isotopic niches between genotypes revealed that heterozygotes were moderately more enriched in δ13C along hair segments grown during fall foraging compared with black‐coated homozygotes. To the extent to which the pattern of elevated δ15N and δ13C may signal the consumption of salmon (Oncorhynchus spp.), as well as the influence of salmon consumption on reproductive fitness, these results suggest that black‐coated heterozygotes could have a minor selective advantage in the fall compared with black‐coated homozygotes. More broadly, our multivariate approach, coupled with knowledge of genetic variation underlying a polymorphic trait, provides new insight into the potential role of a multiniche mechanism in maintaining this rare morph of conservation priority in Canada''s Great Bear Rainforest and could offer new understanding into polymorphisms in other systems. 相似文献
70.
Lena Hess Verena Moos Arnel A. Lauber Wolfgang Reiter Michael Schuster Natascha Hartl Daniel Lackner Thorina Boenke Anna Koren Paloma M. Guzzardo Brigitte Gundacker Anna Riegler Petra Vician Claudia Miccolo Susanna Leiter Mahesh B. Chandrasekharan Terezia Vcelkova Andrea Tanzer Jun Qi Jun James Bradner Gerald Brosch Markus Hartl Christoph Bock Tilmann Bürckstümmer Stefan Kubicek Susanna Chiocca Srividya Bhaskara Christian Seiser 《PLoS genetics》2022,18(8)
The class I histone deacetylases are essential regulators of cell fate decisions in health and disease. While pan- and class-specific HDAC inhibitors are available, these drugs do not allow a comprehensive understanding of individual HDAC function, or the therapeutic potential of isoform-specific targeting. To systematically compare the impact of individual catalytic functions of HDAC1, HDAC2 and HDAC3, we generated human HAP1 cell lines expressing catalytically inactive HDAC enzymes. Using this genetic toolbox we compare the effect of individual HDAC inhibition with the effects of class I specific inhibitors on cell viability, protein acetylation and gene expression. Individual inactivation of HDAC1 or HDAC2 has only mild effects on cell viability, while HDAC3 inactivation or loss results in DNA damage and apoptosis. Inactivation of HDAC1/HDAC2 led to increased acetylation of components of the COREST co-repressor complex, reduced deacetylase activity associated with this complex and derepression of neuronal genes. HDAC3 controls the acetylation of nuclear hormone receptor associated proteins and the expression of nuclear hormone receptor regulated genes. Acetylation of specific histone acetyltransferases and HDACs is sensitive to inactivation of HDAC1/HDAC2. Over a wide range of assays, we determined that in particular HDAC1 or HDAC2 catalytic inactivation mimics class I specific HDAC inhibitors. Importantly, we further demonstrate that catalytic inactivation of HDAC1 or HDAC2 sensitizes cells to specific cancer drugs. In summary, our systematic study revealed isoform-specific roles of HDAC1/2/3 catalytic functions. We suggest that targeted genetic inactivation of particular isoforms effectively mimics pharmacological HDAC inhibition allowing the identification of relevant HDACs as targets for therapeutic intervention. 相似文献