By combining DGGE-PCR method, classical microbiological analysis and light- and electron microscopic observations, it was found that the composition of microbial communities of central Russia regions kefir grains, starter and kefir drink include bacteria of the genera Lactobacillus, Leuconostoc and Lactococcus, and yeast anamorphs of the genera Saccharomyces, Kazachstania and Gibellulopsis. Fifteen prokaryotic and four eukaryotic pure cultures of microorganisms were isolated and identified from kefir grains. It has been shown that members of the genus Lactobacillus prevailed in kefir grains, whereas strains Leuconostoc pseudomesenteroides and Lactococcus lactis dominated in the final product - kefir drink. Yeasts contained in kefir grains in small amounts have reached a significant number of cells in the process of development of this dairy product. The possibility of reverse cell aggregation has been attempted in a mixed cultivation of all isolated pure cultures, but full formation kefir grains is not yet observed after 1.5 years of observation and reinoculations.
Abstract— The growing worldwide production of synthetic plastics leads to increased amounts of plastic pollution. Even though microbial degradation of plastics is known to be a very slow process, this capacity has been found in many bacteria, including invertebrate symbionts, and microscopic fungi. Research in this field has been mostly focused on microbial degradation of polyethylene, polystyrene, and polyethylene terephthalate (PET). Quite an arsenal of different methods is available today for detecting processes of plastic degradation and measuring their rates. Given the lack of generally accepted protocols, it is difficult to compare results presented by different authors. PET degradation by recombinant hydrolases from thermophilic actinobacteria happens to be the most efficient among the currently known plastic degradation processes. Various approaches to accelerating microbial plastic degradation are also discussed.
Unregulated transcription of protein-encoding genes in vitro is dependent on 12-subunit core RNA polymerase II and five general transcription factors; TATA binding protein (TBP), transcription factor (TF)IIB, TFIIE, TFIIF, and TFIIH. Here we describe cloning of the mouse cDNAs encoding TFIIB and the small and large TFIIE and TFIIF subunits. The cDNAs have been used to express the corresponding proteins in recombinant form in Escherichia coli and in Sf21 insect cells, and all proteins have been purified to . 90% homogeneity. We have also purified a recombinant His 6 -tagged mouse TBP to near homogeneity and show that it is active in both a reconstituted mouse in vitro transcription system and a TBP-dependent in vitro transcription system from Saccharomyces cerevisiae. The more complex general transcription factors, TFIIH and RNA polymerase II, were purified more than 1000-fold and to near homogeneity, respectively, from tissue cultured mouse cells. When combined, the purified factors were sufficient to initiate transcription from different promoters in vitro. Functional studies of the S-phase-specific mouse ribonucleotide reductase R2 promoter using both the highly purified system described here (a mouse cell nuclear extract in vitro transcription system) and in vivo R2-promoter reporter gene assays together identify an NF-Y interacting promoter proximal CCAAT-box as being essential for high-level expression from the R2 promoter.Keywords: in vitro transcription; RNA polymerase II; ribonucleotide reductase; mouse general transcription factors.RNA polymerase II catalyses transcription of all proteinencoding genes in eukaryotic cells. The polymerase is dependent on accessory proteins, called the general transcription factors (GTFs) for accurate initiation in vitro [1][2][3][4]. One of these factors, TATA binding protein (TBP), is able to bind directly to promoter DNA and to initiate the sequential addition of the remaining components of the transcription initiation complex. The minimal set of GTFs required for basal transcription in vitro includes, in addition to the RNA polymerase and TBP, also TFIIB, TFIIE, TFIIF, and TFIIH. These factors are both necessary and sufficient for proper initiation of transcription in in vitro transcription systems purified from yeast Saccharomyces cerevisiae, rat and human cells [2,[5][6][7][8].The identification of a minimal set of GTFs, cloning of the corresponding cDNAs from different species and the recently described three-dimensional structure of the yeast RNA polymerase II [9] have facilitated studies of the factors involved in forming a functional preinitiation complex. Swapping experiments of GTFs purified from the distantly related yeasts S. cerevisiae and Schizosaccharomyces pombe have shown that none of the GTFs, except TBP, is individually exchangeable between the different systems [10]. However, the combined substitutions of S. pombe TFIIB and RNA polymerase or TFIIE together with TFIIH, with the corresponding S. cerevisiae factors are possible and thus indicate a specie...
TNF-related apoptosis-inducing ligand (TRAIL) kills tumor cells selectively. We asked how emerging tumor cells escape elimination by TRAIL and how tumor-specific killing by TRAIL could then be restored. We found that TRAIL expression is consistently downregulated in HRAS G12V -transformed cells in stepwise tumorigenesis models derived from four different tissues due to DNA hypermethylation of CpG clusters within the TRAIL promoter. Decitabine de-silenced TRAIL, which remained inducible by interferon, while induction of TRAIL by blocking the HRAS G12V -activated mitogen-activated protein kinase pathway was subordinated to epigenetic silencing. Decitabine induced apoptosis through upregulation of endogenous TRAIL in cooperation with favorable regulation of key players acting in TRAIL-mediated apoptosis. Apoptosis induction by exogenously added TRAIL was largely increased by decitabine. In vivo treatment of xenografted human HRAS G12V -transformed human epithelial kidney or syngenic mice tumors by decitabine blocked tumor growth induced TRAIL expression and apoptosis. Our results emphasize the potential of decitabine to enhance TRAIL-induced apoptosis in tumors and thus provide a rationale for combination therapies with decitabine to increase tumor-selective apoptosis. Mol Cancer Ther; 10(9); 1611-23. Ó2011 AACR.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.