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At least 91 records · Page 5Linked to original sources
PubMed2002

Bulk chemicals from biotechnology: the case of 1,3-propanediol production and the new trends.

The need for a sustainable resource supply, the rapid advances in plant biotechnology and microbial genetics and the strategic shift of major chemical companies into the area of life sciences are some of the driving forces for renewed interest in producing bulk chemicals from renewable resources by biological processes. The microbial production of 1,3-propanediol as briefly reviewed in this article and compared with the competing chemical processes demonstrates the promise and constraints of bioprocesses for bulk chemicals. The new concept of biorefinery and biocommodity engineering and future research needs in this area are also outlined.

Bacteria↗
PubMed2005

Inflammatory bowel disease pathogenesis: therapeutic implications.

The pathogenesis of inflammatory bowel disease (IBD) is complex, involving environmental, genetic, microbial, and immune factors. Therefore, treatment should target components that either predispose to or mediate the chronic inflammatory response of IBD. At the moment it is assumed that all components are necessary to have the typical manifestations of IBD but, in reality, it is unclear to what extent each factor contributes to the disease process, and whether some are more important than others. In addition, some factors are not practical targets; for example, environmental factors are poorly defined, too numerous, and require changes that cannot be implemented by the physician or the patient alone. The same is true for genetic factors that are still not amenable to therapeutic manipulations for technical and ethical reasons. This leaves microbial and immune factors as the two categories that can be selected for therapeutic intervention and where all current treatments are focused. The commensal gut flora can be qualitatively or quantitatively modified with antibiotics, probiotics, or diet, and a better characterization of enteric bacteria strains should help greatly in developing more effective therapies. Most current drugs are focused on inhibiting pro-inflammatory molecules produced by immune cells, including biological agents that block specific cytokines such as tumor necrosis factor-alpha. It is anticipated that combination therapies targeting multiple pathogenic components will prove more effective than those blocking single components of IBD pathogenesis.

Colitis, Ulcerative↗
PubMed1968

Relationship between competence for transfection and for transformation.

Deoxyribonucleic acid (DNA) extracted from phage SPP1 is highly infectious on Bacillus subtilis competent cells; the efficiency of infection is 5 x 10(3) to 6 x 10(3) phage equivalents per plaque-forming unit. This DNA was used to study the relationship between competence for transfection and for transformation. The experiments were concerned with the frequency of infection and transformation in mutants exhibiting different levels of competence, the effect of periodate on competence for infection and for transformation, the competition between phage and bacterial DNA, the transformation of cells preinfected with phage DNA, and the infection of cells pretreated with bacterial DNA. The data show that B. subtilis cells competent for transformation are also competent for transfection and vice versa; transfection with phage DNA represents, therefore, a simple way to measure the total number of competent cells in a culture. The fraction of competent cells, determined by SPP1 DNA infection, varied from 10(-2) to 7 x 10(-2).

Bacillus subtilis↗
PubMed2025

Exploring genetic adaptation and microbial dynamics in engineered anaerobic ecosystems via strain-level metagenomics.

Genetic heterogeneity exists within all microbial populations, with sympatric cells of the same species often exhibiting single-nucleotide variations that influence phenotypic traits, including metabolic efficiency. However, the evolutionary dynamics of these strain-level differences in response to environmental stress remain poorly understood. Here, we present a first-of-its-kind study tracking the adaptive evolution of an anaerobic, carbon-fixing microbiota under a controlled engineered ecosystem focused on carbon dioxide bioconversion into methane. Leveraging strain-resolved metagenomics with an ad hoc variant calling and phasing approach, we mapped mutation trajectories and observed that the two dominant Methanothermobacter species maintained distinct sweeping haplotypes over time, most likely due to niche-specific metabolic roles. By combining population genetic statistics and peptide reconstruction, mer and mcrB genes emerged as potential drivers of archaeal strain-level competition. These findings pave the way for targeted engineering of microbial communities to enhance bioconversion efficiency, with significant implications for sustainable energy and carbon management in anaerobic systems.

Metagenomics↗
PubMed1981

Plasmid reference center registry of transposon (Tn) allocations through July 1981.

The criteria for transposable genetic elements (Cohen, 1976) were stated at the Cold Spring Harbor meeting in 1976 (Campbell et al., 1977) and defined and clarified further (Campbell et al., 1979). At that meeting the Plasmid Reference Center agreed to serve as a clearing house for continuous transposon registry. Interim lists have been previously published (Lederberg, 1978, 1980, Microbial Genetics Bulletin 44 : 31; ibid 48 : 90). A complete file of Tn elements is listed below.

DNA Transposable Elements↗
PubMed1970

Bacillus subtilis mutant altered in spore morphology and in RNA polymerase activity.

A Bacillus subtilis mutant, that was selected for rifampin resistance produces spores with an altered morphology. The mutant spores are pleomorphic and differ both in shape and size from the wild-type spores. They frequently have an exosporium that is usually absent from wild-type spores. The mutant spores are similar to the wild-type spores in heat resistance, dipicolinic acid content, and density, but exhibit a slower rate of germination, outgrowth, and growth. In vitro studies show that the RNA polymerase of the mutant is resistant to rifampin inhibition, whereas the wild-type enzyme is completely inhibited by low concentrations of the antibiotic. Rifampin resistance and the altered spore morphology are contransformed with 100% frequency, suggesting that the altered morphology is caused by an alteration in the RNA polymerase.

Bacillus subtilis↗
PubMed1969

Recombination between guanidine-resistant and dextran sulfate-resistant mutants of type 1 poliovirus.

Mixed infection of monkey kidney cells with two mutants of the LSc2ab strain of poliovirus, one resistant to guanidine and the other resistant to both dextran sulfate and 2-(alpha-hydroxybenzyl)-benzimidazole (HBB), yielded progeny in which the number of gua(r)dex(r) particles exceeded by a factor of 7 to 10 the expected number of similar particles occurring through spontaneous mutation; recombination would explain the fairly high excess of doubly mutant particles that was obtained. Scoring of HBB resistance in 50 gua(r)dex(r) clones suggested that, during recombination, resistance to dextran sulfate is not associated with HBB resistance.

Animals↗
PubMed1985

[Excision process of integrated plasmid pBD12 from the Bacillus subtilis chromosome].

We studied the behavior of pBD12 plasmid integrated into Bacillus subtilis chromosome via homologous recombination. One copy of the plasmid was integrated into the chromosome, it conferred resistance to low concentrations of antibiotics. Clones with enhanced resistance bearing autonomous plasmid DNAs appeared with a frequency 10(-6) in rec+ but not in recE strain with the integrated plasmid. By restriction and hybridization analysis of some excised plasmids, the sites of excision were determined, chromosomal location of pBD12 plasmid was found to be at the terminal fragment of prophage DNA, so that the att site of phi 105 phage is supposed to be situated on the EcoRI fragment of phage DNA.

Bacillus subtilis↗