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Landete J.M.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia
Critical Reviews in Biotechnology | Year: 2016

Lactic acid bacteria (LAB) have a long history of use in fermented foods and as probiotics. Genetic manipulation of these microorganisms has great potential for new applications in food safety, as well as in the development of improved food products and in health. While genetic engineering of LAB could have a major positive impact on the food and pharmaceutical industries, progress could be prevented by legal issues related to the controversy surrounding this technology. The safe use of genetically modified LAB requires the development of food-grade cloning systems containing only the DNA from homologous hosts or generally considered as safe organisms, and not dependent antibiotic markers. The rationale for the development of cloning vectors derived from cryptic LAB plasmids is the need for new genetic engineering tools, therefore a vision from cryptic plasmids to applications in food-grade vectors for LAB plasmids is shown in this review. Replicative and integrative vectors for the construction of food-grade vectors, and the relationship between resistance mechanism and expression systems, will be treated in depth in this paper. Finally, we will discuss the limited use of these vectors, and the problems arising from their use. © 2016 Taylor & Francis.

Warren C.R.,University of Sydney | Aranda I.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia | Cano F.J.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia | Cano F.J.,Technical University of Madrid
Metabolomics | Year: 2012

Past studies of water stress in Eucalyptus spp. generally highlighted the role of fewer than five "important" metabolites, whereas recent metabolomic studies on other genera have shown tens of compounds are affected. There are currently no metabolite profiling data for responses of stress-tolerant species to water stress. We used GC-MS metabolite profiling to examine the response of leaf metabolites to a long (2 month) and severe (Ψ predawn < -2 MPa) water stress in two species of the perennial tree genus Eucalyptus (the mesic Eucalyptus pauciflora and the semi-arid Eucalyptus dumosa). Polar metabolites in leaves were analysed by GC-MS and inorganic ions by capillary electrophoresis. Pressure-volume curves and metabolite measurements showed that water stress led to more negative osmotic potential and increased total osmotically active solutes in leaves of both species. Water stress affected around 30-40% of measured metabolites in E. dumosa and 10-15% in E. pauciflora. There were many metabolites that were affected in E. dumosa but not E. pauciflora, and some that had opposite responses in the two species. For example, in E. dumosa there were increases in five acyclic sugar alcohols and four lowabundance carbohydrates that were unaffected by water stress in E. pauciflora. Re-watering increased osmotic potential and decreased total osmotically active solutes in E. pauciflora, whereas in E. dumosa re-watering led to further decreases in osmotic potential and increases in total osmotically active solutes. This experiment has added several extra dimensions to previous targeted analyses of water stress responses in Eucalyptus, and highlights that even species that are closely related (e. g. congeners) may respond differently to water stress and re-watering. © 2011 Springer Science+Business Media, LLC.

Landete J.M.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia
Trends in Biotechnology | Year: 2016

Bacteria respond to their external environment by modulating gene expression in the presence of certain effector molecules. The adaptive responses are mediated by transcriptional regulators that, after binding to the DNA, recognize these effector molecules and modify transcription. Some applications of regulatory proteins are reviewed here. © 2016 Elsevier Ltd.

Blazquez A.-B.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia | Saiz J.-C.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia
Virus Research | Year: 2010

Since its first detection in New York in 1999, West Nile virus (WNV) has already caused over 1000 human deaths in the U.S. Although the virus is usually transmitted by mosquito bites; other routes, such as intrauterine and breastfeeding, have been occasionally reported in humans. To investigate alternative routes of WNV transmission, mice were inoculated during gestation and after delivery, and offspring from infected and non-infected mothers were interchanged and nursed as foster babies. Intrauterine and breastfeeding transmission was confirmed after WNV detection, by quantitative RT-PCR and viral culture infectivity, in babies born to infected mothers and in newborns that were nursed by mothers infected after delivery. All infected mothers, either experimentally or after cannibal ingestion of infected fostered babies, succumbed to the disease, as did most of their nursed babies. These results indicate that WNV is efficiently transmitted by vertical routes (intrauterine and lactation) and after cannibal ingestion of infected animals. © 2010 Elsevier B.V.

Ortiz S.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia | Lopez V.,Institute Salud Carlos III | Martinez-Suarez J.V.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia
Food Microbiology | Year: 2014

The aims of this study were to characterize the different strains of Listeria monocytogenes collected at an Iberian pork processing plant and to investigate whether their specific characteristics were associated with prolonged survival in the plant. Using pulsed-field gel electrophoresis (PFGE), 29 PFGE types were previously identified during a three-year period. Eight of these PFGE types persisted in the plant during that period. In the present study, a subset of 29 PFGE type strains, which represented the 29 different PFGE types, was further characterized by assessing the potential virulence, and using motility, surface attachment, and antimicrobial susceptibility tests. After changing the disinfection procedures in the plant, the isolation rate of L.monocytogenes decreased, and only four of the 29 PFGE types, including three of the eight persistent PFGE types, were found the following year. These four "surviving" PFGE types included three from PCR serogroup IIa that were characterized by their low virulence mutations and low-level resistance to benzalkonium chloride (BAC). Furthermore, these PFGE types comprised the only BAC-resistant isolates found in the study, and they appear to have been selected due to the control of Listeria contamination. The resistance to increased sublethal concentrations of disinfectants may lead to prolonged survival of L.monocytogenes in food plants. © 2013 Elsevier Ltd.

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