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Results for “Plastic transforming enzyme”

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PubMed2026

Polyethylene transformation by a psychrotolerant Rhodococcus strain assessed by transcriptomics and 13C-isotope tracing.

Polyethylene is increasingly accumulating in nature, including remote places like the Arctic. While abiotic processes fragment polyethylene in situ, biotic transformation by microorganisms is assumed to occur. However, the enzymes and pathways involved remain poorly characterized. In this study, we used an in-house biobank from cold environments to screen for potential bacteria capable of degrading polyethylene by screening the strains in silico using the database PlasticDB and in vivo using a fluorescence-based assay. Using transcriptomic and proteomic analyses to identify genes in promising candidate strains that encode extracellular enzymes potentially capable of degrading PE, we selected a Rhodococcus erythropolis strain and two of its enzymes: a hypothetical protein (Hypr1) and a lipase family protein (Lip2). Expressing the candidate genes heterologously in Escherichia coli resulted in positive results in the fluorescence-based assay for polyethylene transformation. Applying 13C-labelled polyethylene for assessing and estimating polyethylene transformation and carbon assimilation, we found that R. erythropolis and both untransformed and recombinant E. coli extracellularly transformed the initially added polyethylene after 70 days. In addition, untransformed E. coli and R. erythropolis converted small, but significant amounts of polyethylene-derived carbon to carbon dioxide. The 13C-label was also traced into the bacterial biomass of R. erythropolis. Overall, our results provide evidence for biotic transformation of untreated polyethylene and suggests a hypothetical protein and a lipase family protein as two novel enzyme candidates associated with PE transformation.

Rhodococcus↗

PubMed1979

[Dynamics of the connective tissue changes in rats in the process of tumor formation induced by ethacryl (AKR-15) plastic].

Morphological studies of the rat connective tissue around the implanted plates, made from a plastic Ethacryl (AKP-15) being employed in orthopedic stomatology, have demonstrated a gradual reduction of the proliferative activity of the connective tissue capsule fibroblasts, followed 6 months later by the appearance of diffuse and then focal proliferates in the internal layer with subsequent development of tumors. A histological assay of the collagen-formation revealed no dystrophic changes in the connective tissue characteristic of other types of blastomogenesis. The pattern of diformazane depositing, when histochemically assaying oxido-reduction enzymes, may evidence the cell damage of the connective tissue capsules around the implant in the first months of the experiment.

Acrylic Resins↗

PubMed1979

Oncogenic transformation of rat lung epitheloid cells by SV 40 DNA and restriction enzyme fragments.

Rat epitheloid lung cells were transformed with various preparations of SV40 dna using the Ca2+-precipitation technique. The amount of SV40 genetic information integrated into transformed clones was evaluated by DNA-DNA renaturation kinetics. The growth properties on plastic and in soft-agar were examined, as well as the ability to induce tumors in syngeneic new-born animals or in adult nude mice. One particular transformed line, which had received the Hpa II/BamH I A (59 per cent) fragment, was found to contain about 3 integrated copies of this fragment per cell and no significant amount of the Hpa II/BamH I B (41 per cent) fragment. This line which grew to high saturation densities and efficiently formed clones in low serum on plastic, produced tumors in both syngeneic rats and nude mice. Thus the Hpa II/BamH I A fragment, which mainly includes early viral information, was sufficient to impart these properties to rat epitheloid lung cells.

Animals↗

PubMed2025

Logan: Planetary-Scale Genome Assembly Surveys Life's Diversity.

The breadth of life's diversity is unfathomable, but public nucleic acid sequencing data offers a window into the dispersion and evolution of genetic diversity across Earth. However the rapid growth and accumulation of sequence data have outpaced efficient analysis capabilities. The largest collection of freely available sequencing data is the Sequence Read Archive (SRA), comprising 27.3 million datasets or 5 × 1016 basepairs. To realize the potential of the SRA, we constructed Logan, a massive sequence assembly transforming short reads into long contigs and compressing the data over 100-fold, enabling highly efficient petabase-scale analysis. We created Logan-Search, a k-mer index of Logan for free planetary-scale sequence search, returning matches in minutes. We used Logan contigs to identify >200 million plastic-degrading enzyme homologs, and validate novel enzymes with catalytic activities exceeding current reference standards. Further, we vastly expand the known diversity of proteins (30-fold over UniRef50), plasmids (22-fold over PLSDB), P4 satellites (4.5-fold), and the recently described Obelisk RNA elements (3.7-fold). Logan also enables ecological and biomedical data mining, such as global tracking of antimicrobial resistance genes and the characterization of viral reactivation across millions of human BioSamples. By transforming the SRA, Logan democratizes access to the world's public genetic data and opens frontiers in biotechnology, molecular ecology, and global health.

Journal Article↗

PubMed1977

[Bacterial recombination].

The most perspective trends in studying the mechanisms of genetic exchanges in bacteria are discussed. They are the following. 1. Comparison of the recombination stages in various biological phenomena such as transformation, transduction (generalized), conjugation (common and single-stranded) and transfection. 2. Characterization of genetic determinants and basic enzymes of the recombination process in Rec-systems of different bacteria. 3. Determination of some peculiar features of the intragenic recombination and finding a possible approach to their research. 4. Analysis of some plastic properties of the DNA structure and their application to the modern ideas in the formulation of a molecular mechanism of genetic recombination.

Bacillus subtilis↗

PubMed1979

Maintenance of adult rat hepatocytes on C3H/10T1/2 cells.

A procedure is described for maintaining primary cultures of adult rat hepatocytes on a layer of irradiated C3H/10T1/2 cells. These hepatocytes were capable of metabolizing the liver carcinogen N-2-acetylaminofluorene to water-soluble products and after 14 days in culture could still metabolize approximately 70% of the Day 1 level. Hepatocytes maintained on the C3H/10T1/2 cells were inducible for the liver-specific enzyme tyrosine aminotransferase, and exhibited approximately a 4-fold induction by hydrocortisone during a 10-day culture period. Morphologically, these hepatocytes retained many characteristics of hepatocytes in vivo. By contrast, hepatocytes maintained on plastic lost both N-2-acetylaminofluorene-metabolizing ability and tyrosine aminotransferase activity by Day 5. This was presumably due to degeneration of the hepatocytes and an overgrowth by fibroblasts. The maintenance of morphologically and biochemically functional hepatocytes in culture on feeder cells may provide a valuable approach for studying drug metabolism and liver cell transformation in vitro.

2-Acetylaminofluorene↗