Conditionally transformable cells of primate origin in which 'untransformed' and 'transformed' cells derived from the same source grow in culture, has been used as an experimental system for testing selective inhibition of proliferating cells by chemotherapeutic agents. The cytotoxic agents Adriamycin and Mitomycin C fail to recognise "tumour cells" in a heterogenous population and thus differ from the non-toxic and non-carcinogenic agent L-canavanine. 相似文献
A new species of the genus Cirrhimuraena (Anguilliformes: Ophichthidae), Cirrhimuraena indica sp. nov., is described based on eight specimens collected from the Paradip (Odisha) and Petuaghat harbours (West Bengal) along the Bay of Bengal. The species is distinct in having the upper jaw fringed with 16–17 cirri before posterior nostril and 4–5 in between the anterior and posterior nostrils on the side; dorsal fin originates above the level of gill opening, predorsal length is 9.3–10.9 in total length; the head is relatively large, the length is 9.3–9.8 in total length; no infraorbital pores are observed between the nostrils; teeth are numerous, small, conical and in bands on each jaw; pores are present before the gill opening 10–11 and before anus 47–48; pectoral-fin length is 2.4–2.8 in head length; predorsal vertebrae are 8–10, pre-anal vertebrae 43–47 and total vertebrae 164–169. In the maximum likelihood tree analysis for COI gene, the new species belongs to the same clade as the other congener of Cirrhimuraena chinensis and is separated from the species morphologically and genetically. 相似文献
Gut microbiota play important role in maintaining health. Probiotics are believed to augment it further. We aimed at comparing effects of probiotics, Lactobacillus acidophilus (LA) and Bacillus clausii (BC) (a) on the gut microbiota abundance and diversity and (b) their contributions to control intestinal dysbiosis and inflammation in Th1- and Th2-biased mice following Salmonella infection. We report how could gut microbiota and the differential immune bias (Th1 or Th2) of the host regulate host responses when challenged with Salmonella typhimurium in the presence and absence of either of the probiotics. LA was found to be effective in ameliorating the microbial dysbiosis and inflammation caused by Salmonella infection, in Th1 (C57BL/6) and Th2 (BALB/c)-biased mouse. BC was able to ameliorate Salmonella-induced dysbiosis and inflammation in Th2 but not in Th1-biased mouse. These results may support probiotics LA as a treatment option in the case of Salmonella infection.
The conjugation of the protein transduction domain (PTD) from the HIV-1 Tat protein to shell-cross-linked (SCK) nanoparticles is reported as a method to facilitate cell surface binding and transduction of SCK nanoparticles. Attaching increasing numbers of peptide sequences to SCK nanoparticles in a global solution-state functionalization strategy has been devised as a method for increasing the efficiency of the cell-penetrating process. The numbers of peptides per SCK were controlled through stoichiometric balance and measured experimentally by two independent methods, UV-visible spectroscopy and phenylglyoxal analysis. PTD was conjugated in (0.005, 0.01, and 0.02) molar ratios, relative to the acrylic acid residues in the shell, to the SCK nanoparticles resulting in SCK populations possessing nominally 52, 104, and 210 (41, 83, and 202 as measured by phenylglyoxal analysis) PTD peptides per particle, respectively. The methodologies for the block copolymer and nanoparticle syntheses, peptide derivatization, and characterization of peptide-functionalized SCK nanoparticles are reported and the feasibility and efficiency of intracellular internalization of the respective SCKs were quantified. 相似文献
An efficient method of mass propagation of Dendrobium chrysotoxum Lindl. was developed using a shoot-tip culture system. Both direct and callus-mediated formation of protocorm-like bodies
(PLBs) occurred from the basal cut surface of explants. Frequency of callusing was best in the presence of 2 μM thidiazuron
(TDZ) or N6-benzylaminopurine (BAP). The callus exhibited complete hormone autonomy for growth and differentiation of PLBs and was maintained
for 18 months without any exogenous growth regulators, an aspect important for minimising somaclonal variation. However, the
rate of callus growth and PLB formation varied with application of cytokinin and auxin. In addition, the callus exhibited
a differential sensitivity to the exogenous cytokinins. While BAP promoted callus growth and PLB differentiation, TDZ was
inhibitory to callus mediated PLB formation and caused extensive necrosis of callus. Although α-naphthaleneacetic acid (NAA)
had no significant effect on the induction of callus, subsequent growth was best in its presence. Using a 3-month subculture
period, a 69-fold increase in callus weight was achieved with 0.5 μM NAA, while as many as 133 PLBs could be obtained per
100 mg callus in the presence of 1 μM NAA. For direct PLB formation, the optimum cytokinin dosage was dependent upon the type
of cytokinin used. While TDZ was most effective at a concentration of 1 μM (15 PLBs per explant), for similar PLB yield the
application of 8 μM BAP was essential. 相似文献
The mammalian AMP-activated protein kinase (AMPK) is an obligatory αβγ heterotrimeric complex carrying a carbohydrate-binding module (CBM) in the β-subunit (AMPKβ) capable of attaching AMPK to glycogen. Nonetheless, AMPK localizes at many different cellular compartments, implying the existence of mechanisms that prevent AMPK from glycogen binding. Cell-free carbohydrate binding assays revealed that AMPK autophosphorylation abolished its carbohydrate-binding capacity. X-ray structural data of the CBM displays the central positioning of threonine 148 within the binding pocket. Substitution of Thr-148 for a phospho-mimicking aspartate (T148D) prevents AMPK from binding to carbohydrate. Overexpression of isolated CBM or β1-containing AMPK in cellular models revealed that wild type (WT) localizes to glycogen particles, whereas T148D shows a diffuse pattern. Pharmacological AMPK activation and glycogen degradation by glucose deprivation but not forskolin enhanced cellular Thr-148 phosphorylation. Cellular glycogen content was higher if pharmacological AMPK activation was combined with overexpression of T148D mutant relative to WT AMPK. In summary, these data show that glycogen-binding capacity of AMPKβ is regulated by Thr-148 autophosphorylation with likely implications in the regulation of glycogen turnover. The findings further raise the possibility of regulated carbohydrate-binding function in a wider variety of CBM-containing proteins. 相似文献
DNA-damage-induced phospho-signaling has been studied for decades, with a focus mainly on initiation of the signaling cascade, and the kinases activated by DNA lesions. It is widely accepted that the balance of phosphorylation needs to be restored and/or maintained by phosphatases, yet there have only been sporadic efforts to investigate the impact of phosphatases on DNA repair. Recent advances in phosphoproteomic strategies and implementation of large genetic screens indicate that these enzymes play pivotal roles in these signaling networks. Dephosphorylation of repair proteins is crucial for efficient DNA repair, and the recommencement of cell division post-repair. Here, we focus on serine/threonine phosphatases implicated in dephosphorylation of DNA repair factors, summarizing recent findings and speculating on untested roles of phosphatases in the DNA damage response. 相似文献
We report on the synthesis, biological evaluation and structure-activity relationships for a series of 3-benzazepine derivatives as 5-HT(2C) receptor agonists. The compounds were evaluated in functional assays measuring [3H] phosphoinositol turnover in HEK-293 cells transiently transfected with h5-HT(2C), h5-HT(2A) or h5-HT(2B) receptors. Several compounds are shown to be potent and selective 5-HT(2C) receptor agonists, which decrease food intake in a rat feeding model. 相似文献