Search results for "genetic engineering"

Mutation of the oxaloacetate decarboxylase gene of Lactococcus lactis subsp. lactis impairs the growth during citrate metabolism

2007

 ; Aims: Citrate metabolism generates metabolic energy through the generation of a membrane potential and a pH gradient. The purpose of this work was to study the influence of oxaloacetate decarboxylase in citrate metabolism and intracellular pH maintenance in relation to acidic conditions. Methods and Results: A Lactococcus lactis oxaloacetate decarboxylase mutant [ILCitM (pFL3)] was constructed by double homologous recombination. During culture with citrate, and whatever the initial pH, the growth rate of the mutant was lower. In addition, the production of diacetyl and acetoin was altered in the mutant strain. However, our results indicated no relationship with a change in the maintenanc…

Production of Antibacterial Compounds from Actinomycetes

2016

Actinomycetes are soil-dwelling Gram-positive bacteria, industrially relevant as producers of a wide range of bioactive secondary metabolites, including many antibiotics of clinical and commercial importance.The understanding of actinomycete biology has been based on extensive studies on the model organism Streptomyces coelicolor over many years and on the availability of its complete genome sequence. This bacterium has an unusual complex developmental cycle that includes programmed cell death phenomena that make this bacterium a multicellular prokaryotic model.Morphological differentiation in S. coelicolor is strictly related to physiological differentiation: indeed the onset of morphologi…

Evolution-guided evaluation of the inverted terminal repeats of the synthetic transposon Sleeping Beauty.

2018

Abstract Sleeping Beauty (SB) is a synthetic Tc1/mariner transposon that is widely used for genetic engineering in vertebrates, including humans. Its sequence was derived from a consensus of sequences found in fish species including the Atlantic salmon (Salmo salar). One of the functional components of SB, the transposase enzyme, has been subject to extensive mutagenesis yielding hyperactive protein variants for advanced applications. The second functional component, the transposon inverted terminal repeats (ITRs), has so far not been extensively modified, mainly due to a lack of natural sequence information. Importantly, as genome sequences become available, they can provide a rich source …

Improved acid tolerance of a recombinant strain of Escherichia coli expressing genes from the acidophilic bacterium Oenococcus oeni.

2001

Aims:Oenococcus oeni is a lactic acid bacterium used in wine fermentation. Two open reading frames (orfB and orfC) were identified in the upstream region of the hsp18 gene, encoding the small heat-shock protein Lo18. Expression of these genes in conditions of acid stress was studied in Escherichia coli. Methods and Results: Sequence analysis showed that orfB encodes a putative transcriptional regulator of the LysR family. The protein encoded by orfC shares homologies with multi-drug resistance systems. Heterologous expression of orfB, orfC and hsp18 genes in Escherichia coli significantly enhanced the viability of the host strain under acidic conditions. Conclusions: It was demonstrated tha…

Reverse-engineering post-transcriptional regulation of gap genes in Drosophila melanogaster

2013

16 páginas, 6 figuras, 1 tabla

Use of a Genetically Engineered Strain To Evaluate the Pathogenic Potential of Yeast Cell and Filamentous Forms duringCandida albicansSystemic Infect…

2007

ABSTRACTThe pathogenesis ofCandida albicanssystemic infection is complex and results from the balance between its intrinsic virulence attributes and the host immune responses. Morphogenetic transitions between yeast cell and filamentous forms are considered one of the main virulence attributes inC. albicans. We have examined the pathogenesis of a genetically engineeredC. albicansstrain in which morphogenetic conversions can be externally manipulated in immunodeficient mice; these included B-cell deficient, nude (T cell deficient), SCID (lacking both functional T and B cells), and DBA/2N (C5 deficient with impaired neutrophil activity) mice. We also tested mice severely immunosuppressed by c…

Correlation of plasmid DNA supercoiling and the efficiency of plasmid gene transcription

2007

Engineering a Saccharomyces cerevisiae Wine Yeast That Exhibits Reduced Ethanol Production during Fermentation under Controlled Microoxygenation Cond…

2006

ABSTRACTWe recently showed that expressing an H2O-NADH oxidase inSaccharomyces cerevisiaedrastically reduces the intracellular NADH concentration and substantially alters the distribution of metabolic fluxes in the cell. Although the engineered strain produces a reduced amount of ethanol, a high level of acetaldehyde accumulates early in the process (1 g/liter), impairing growth and fermentation performance. To overcome these undesirable effects, we carried out a comprehensive analysis of the impact of oxygen on the metabolic network of the same NADH oxidase-expressing strain. While reducing the oxygen transfer rate led to a gradual recovery of the growth and fermentation performance, its i…

Genetically engineered V79 Chinese hamster cells metabolically activate the cytostatic drugs cyclophosphamide and ifosfamide.

1990

V79 cells, genetically engineered to express active cytochromes P450IIB1 and P450IA1, were used to study the cytotoxicity and mutagenicity of cyclophosphamide and ifosfamide. Cyclophosphamide, tested up to a concentration of 2 mM, was not cytotoxic in V79 nor in the P450IA1-expressing V79-derived cell line XEM2. Pronounced cytotoxicity was, however, observed in the P450IIB1-expressing V79-derived cell line SD1. Induction of gene mutations (acquisition of 6-thioguanine resistance) was observed in SD1 cells as well, but the effects were weak. Ifosfamide was inactive in V79 cells, but was cytotoxic in SD1 cells. Ifosfamide mustard, an active metabolite of ifosfamide, was equally cytotoxic and …

Midbiotics : conjugative plasmids for genetic engineering of natural gut flora

2019

ABSTRACTThe possibility to modify gut bacterial flora has become an important goal, and various approaches are used to achieve desirable communities. However, the genetic engineering of existing microbes in the gut, which are already compatible with the rest of the community and host immune system, has not received much attention. Here, we discuss and experimentally evaluate the possibility to use modified and mobilizable CRISPR-Cas9-endocing plasmid as a tool to induce changes in bacterial communities. This plasmid system (briefly midbiotic) is delivered from bacterial vector into target bacteria via conjugation. Compared to, for example, bacteriophage-based applications, the benefits of c…