Publications by authors named "Norma Ramirez Ramirez"

is a spore forming, anaerobic, Gram-positive bacterium that causes a range of diseases in humans and animals. forms spores, structures that are derived from the vegetative cell under conditions of nutrient deprivation and that allows survival under harsh environmental conditions. To return to vegetative growth, spores must germinate when conditions are favorable.

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The origin of life on Earth is associated with the Precambrian era, in which the existence of a large diversity of microbial fossils has been demonstrated. Notwithstanding, despite existing evidence of the emergence of life many unsolved questions remain. The first question could be as follows: Which was the inorganic structure that allowed isolation and conservation of the first biomolecules in the existing reduced conditions of the primigenial era? Minerals have been postulated as the ones in charge of protecting theses biomolecules against the external environment.

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During sporulation Bacillus subtilis Mfd couples transcription to nucleotide excision repair (NER) to eliminate DNA distorting lesions. Here, we report a significant decline in sporulation following Mfd disruption, which was manifested in the absence of external DNA-damage suggesting that spontaneous lesions activate the function of Mfd for an efficient sporogenesis. Accordingly, a dramatic decline in sporulation efficiency took place in a B.

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Cr(VI) is mutagenic and teratogenic and considered an environmental pollutant of increasing concern. The use of microbial enzymes that convert this ion into its less toxic reduced insoluble form, Cr(III), represents a valuable bioremediation strategy. In this study, we examined the YhdA enzyme, which belongs to the family of NADPH-dependent flavin mononucleotide oxide reductases and possesses azo-reductase activity as a factor that upon overexpression confers protection on from the cytotoxic effects promoted by Cr(VI) and counteracts the mutagenic effects of the reactive oxygen species (ROS)-promoted lesion 8-OxoG.

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Article Synopsis
  • Bacteria trigger global gene expression programs, like the SOS response, to deal with DNA damage from environmental factors such as hexavalent chromium (Cr(VI)).
  • Genetic damage caused by Cr(VI) activates the SOS response, indicating that DNA repair mechanisms like homologous recombination and nucleotide excision repair are crucial for bacterial survival under stress.
  • The study finds that Cr(VI) not only increases the formation of harmful DNA-protein cross-links but also promotes mutations in bacteria, showing how pollutants can initiate protective responses against toxic effects.
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Elucidating how a population of non-growing bacteria generates mutations improves our understanding of phenomena like antibiotic resistance, bacterial pathogenesis, genetic diversity and evolution. To evaluate mutations that occur in nutritionally stressed non-growing bacteria, we have employed the strain YB955, which measures the reversions rates to the chromosomal auxotrophies and (Sung and Yasbin, 2002). This gain-of-function system has successfully allowed establishing the role played by repair systems and transcriptional factors in stress-associated mutagenesis (SPM) (Barajas- Ornelas , 2014 ; Gómez- Marroquín , 2016 ).

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The nucleotide excision repair (NER) and spore photoproduct lyase DNA repair pathways are major determinants of Bacillus subtilis spore resistance to UV radiation. We report here that a putative ultraviolet (UV) damage endonuclease encoded by ywjD confers protection to developing and dormant spores of B. subtilis against UV DNA damage.

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The soil microorganism Myxobacter Sp. AL-1 regulates in a differential manner the production of five extracellular cellulases during its life cycle. The nucleotide sequence of a cel9-cel48 cluster from the genome of this microorganism was recently obtained.

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Northern-blot analysis revealed that cel9 and cel48, which encode family 9 and 48 glycosyl hydrolases, respectively, were expressed as a bicistronic mRNA in the soil bacterium Myxobacter sp. AL-1. The two cistrons of the cel9-cel48 mRNA as well as their encoded products were detected in stationary phase cultures of Myxobacter sp.

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The chemical design of metal complexes of the type [Cu(phen)(antib)](+) (where antib is a quinolone or a fluoroquinolone) has been carried out in an approach to better understand how the coordination of their components affect the activity of quinolones. The ability of [Cu(phen)(nal)](+) to interact with DNA in vivo and its capacity to promote the degradation of plasmid and chromosomal DNA, under reductive conditions has been previously reported. However whether this compound utilizes other intracellular targets to promote bacterial killing was a question that deserved to be answered.

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