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1 Q&A 1047 Views Apr 20, 2023

In this study, a sonication-based DNA extraction method was developed, in which the whole process can be finished within 10 min. This method is almost zero cost and time-saving, which is useful for high throughput screening, especially in the screening of mutants generated in random mutagenesis. This method is effective in genomic DNA extraction for PCR amplification in several Gram-positive bacteria, including Bacillus cereus, Bacillus thuringiensis, Bacillus subtilis, and Listeria monocytogenes.

0 Q&A 817 Views Sep 5, 2022

Geobacillus kaustophilus, a thermophilic Gram-positive bacterium, is an attractive host for the development of high-temperature bioprocesses. However, its reluctance against genetic manipulation by standard methodologies hampers its exploitation. Here, we describe a simple methodology in which an artificial DNA segment on the chromosome of Bacillus subtilis can be transferred via pLS20-mediated conjugation resulting in subsequent integration in the genome of G. kaustophilus. Therefore, we have developed a transformation strategy to design an artificial DNA segment on the chromosome of B. subtilis and introduce it into G. kaustophilus. The artificial DNA segment can be freely designed by taking advantage of the plasticity of the B. subtilis genome and combined with the simplicity of pLS20 conjugation transfer. This transformation strategy would adapt to various Gram-positive bacteria other than G. kaustophilus.


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0 Q&A 2232 Views Jan 20, 2021

In Mycoplasma agalactiae, two simultaneous processes of DNA transfer have been described that require direct cell-to-cell contact and are similar to conjugation. One involves the self-transmission of an integrative conjugative element (ICE) while the second concerns the horizontal transfer of large and small fragments of chromosomal DNA. Here, we describe an optimized conjugation protocol for the horizontal transfer of ICE or chromosomal DNA carrying antibiotic resistance markers (i.e., tetracycline, gentamicin, puromycin) from donor to recipient mycoplasma cells. Calculation of the conjugation frequencies, selection and characterization of transconjugants are detailed. This protocol has been developed with M. agalactiae but has been successfully used for M. bovis and can be adapted to other related mycoplasma species.

0 Q&A 7921 Views Sep 5, 2020
Genetic transformation is crucial for both investigating gene functions and for engineering of crops to introduce new traits. Rice (Oryza sativa L.) is an important model in plant research, since it is the staple food for more than half of the world’s population. As a result, numerous transformation methods have been developed for both indica and japonica rice. Since breeders continuously develop new rice varieties, transformation protocols have to be adapted for each new variety. Here we provide an optimized transformation protocol with detailed tips and tricks for a new African variety Komboka using immature embryos. In Komboka, we obtained an apparent transformation rate of up to 48% for GUS/GFP reporter gene constructs using this optimized protocol. This protocol is also applicable for use with other elite indica rice varieties.
0 Q&A 4962 Views Jan 5, 2020
Ancient fermented food has been studied mainly based on residue analysis and recipes and reconstruction attempts were performed using modern domesticated yeast. Furthermore, microorganisms which participated in fermentation were studied using ancient-DNA techniques. In a recent paper, we presented a novel approach based on the hypothesis that enriched yeast populations in fermented beverages could have become the dominant species in storage vessels and their descendants could be isolated and studied today. Here we present a pipeline for isolation of yeast from clay vessels uncovered in archeological sites and transferred to the microbiology lab where they can be isolated and characterized. This method opens new avenues for experimental archeology and enables attempts to recreate ancient food and beverages using the original microorganisms.
0 Q&A 3077 Views Sep 5, 2019
Debaryomyces hansenii is one of the most osmotolerant and halotolerant yeasts. Further, its association with traditional cheese and meat products imparting special flavors to these products project this yeast with enormous biotechnological potential in the agrofood sector. However, lack of an efficient transformation system in D. hansenii still direct the complementation based assay in S. cerevisiae mutants for functional analysis of D. hansenii genes. Here, we have described the development of an efficient transformation system for D. hansenii that is based on a histidine auxotrophic recipient strain, DBH9 (generated by UV induced random mutagenesis), and the DhHIS4 gene as the selectable marker (Minhas et al., 2009). Moreover, the same method has also been employed for gene disruption in D. hansenii by homologous recombination.
0 Q&A 3165 Views Aug 20, 2019
For natural transformation to occur, bacterial cells must first develop a programmed physiological state called competence. Competence in Bacillus subtilis, which occurs only in a fraction of cells, is a transient stress response that allows cells to take up DNA from the environment. During natural chromosomal transformation, the internalized linear single-stranded (ss) DNA recombines with the identical (homologous) or partially identical (homeologous) sequence of the resident duplex. The length of the integrated DNA, which can be measured, depends on the percentage of sequence divergence between the donor (internalized) and the recipient (chromosomal) DNAs.

The following protocol describes how to induce the development of competence in B. subtilis cells, how to transform them with donor DNAs representing different percentages of sequence divergence compared with the recipient chromosomal DNA, how to calculate the chromosomal transformation efficiency for each of them, and how to amplify the chromosomal DNA from the transformants in order to measure the length in base pairs (bp) of the integrated donor DNA.
0 Q&A 7495 Views Dec 5, 2018
Bacillus subtilis (B. subtilis) is a model Gram-positive organism used to study a variety of physiological states and stress responses, one of which is the development of competence. Competence refers to the physiological state of a cell which allows it to be transformed naturally. Through induction of competence, the efficiency of natural transformation can be quantified by plating colony forming units (CFU) and transforming units (TFU). Here we describe a protocol for quantifying relative transformability using B. subtilis.
0 Q&A 6514 Views Jul 5, 2018
Natural competence can be activated in Lactoccocus lactis subsp lactis and cremoris upon overexpression of ComX, a master regulator of bacterial competence. Herein, we demonstrate a method to activate bacterial competence by regulating the expression of the comX gene by using a nisin-inducible promoter in an L. lactis strain harboring either a chromosomal or plasmid-encoded copy of nisRK. Addition of moderate concentrations of the inducer nisin resulted in concomitant moderate levels of ComX, which led to an optimal transformation rate (1.0 x 10-6 transformants/total cell number/g plasmid DNA). Here, a detailed description of the optimized protocol for competence induction is presented.
0 Q&A 11591 Views May 5, 2017
CRISPR-Cas is a prokaryotic adaptive immune system that prevents uptake of mobile genetic elements such as bacteriophages and plasmids. Plasmid transfer between bacteria is of particular clinical concern due to increasing amounts of antibiotic resistant pathogens found in humans as a result of transfer of resistance plasmids within and between species. Testing the ability of CRISPR-Cas systems to block plasmid transfer in various conditions or with CRISPR-Cas mutants provides key insights into the functionality and mechanisms of CRISPR-Cas as well as how antibiotic resistance spreads within bacterial communities. Here, we describe a method for quantifying the impact of CRISPR-Cas on the efficiency of plasmid transfer by conjugation. While this method is presented in Staphylococcus species, it could be more broadly used for any conjugative prokaryote.



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