Mexico City, Mexico
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Reyes-Leon A.,Instituto Nacional Of Pediatria | Nieto-Patlan E.,ENCB IPN | Hansen L.M.,University of California at Davis | Burgueno J.,Crop Research Informatics Laboratory | And 5 more authors.
Infection and Immunity | Year: 2012

The best-studied Helicobacter pylori virulence factor associated with development of peptic ulcer disease or gastric cancer (GC) rather than asymptomatic nonatrophic gastritis (NAG) is the cag pathogenicity island (cagPAI), which encodes a type IV secretion system (T4SS) that injects the CagA oncoprotein into host epithelial cells. Here we used real-time reverse transcription-PCR (RT-PCR) to measure the in vivo expression of genes on the cagPAI and of other virulence genes in patients with NAG, duodenal ulcer (DU), or GC. In vivo expression of H. pylori virulence genes was greater overall in gastric biopsy specimens of patients with GC than in those of patients with NAG or DU. However, since in vitro expression of cagA was not greater in H. pylori strains from patients with GC than in those from patients with NAG or DU, increased expression in GC in vivo is likely a result of environmental conditions in the gastric mucosa, though it may in turn cause more severe pathology. Increased expression of virulence genes in GC may represent a stress response to elevated pH or other environmental conditions in the stomach of patients with GC, which may be less hospitable to H. pylori colonization than the acidic environment in patients with NAG or DU. © 2012, American Society for Microbiology.

Airways infection with Mycobacterium tuberculosis (Mtb) is contained mostly by T cell responses, however, Mtb has developed evasion mechanisms which affect antigen presenting cell (APC) maturation/recruitment delaying the onset of Ag-specific T cell responses. Hypothetically, bypassing the natural infection routes by delivering antigens directly to APCs may overcome the pathogens naturally evolved evasion mechanisms, thus facilitating the induction of protective immune responses. We generated a murine monoclonal fusion antibody (-DEC-ESAT) to deliver Early Secretory Antigen Target (ESAT)-6 directly to DEC205+ APCs and to assess its in vivo effects on protection associated responses (IFN- production, in vivo CTL killing, and pulmonary mycobacterial load). Treatment with -DEC-ESAT alone induced ESAT-6-specific IFN- producing CD4+ T cells and prime-boost immunization prior to Mtb infection resulted in early influx (d14 post-infection) and increased IFN-+ production by specific T cells in the lungs, compared to scarce IFN- production in control mice. In vivo CTL killing was quantified in relevant tissues upon transferring target cells loaded with mycobacterial antigens. During infection, -DEC-ESAT-treated mice showed increased target cell killing in the lungs, where histology revealed cellular infiltrate and considerably reduced bacterial burden. Targeting the mycobacterial antigen ESAT-6 to DEC205+ APCs before infection expands specific T cell clones responsible for early T cell responses (IFN- production and CTL activity) and substantially reduces lung bacterial burden. Delivering mycobacterial antigens directly to APCs provides a unique approach to study in vivo the role of APCs and specific T cell responses to assess their potential anti-mycobacterial functions.

PubMed | CINVESTAV, Leiden University, ENCB IPN and INPer.
Type: | Journal: SpringerPlus | Year: 2015

Neutrophils are one the earliest, crucial innate defenses against innumerable pathogens. Their main microbicidal activities include phagocytosis and degranulation, with many pharmacologically active molecules contributing to inflammation. Recently, a novel antimicrobial mechanism was discovered; the Neutrophil Extracelullar Traps (NETs) formed by extrusion of DNA and associated molecules (histones, elastase, antimicrobial peptides, among others) which trap and kill microorganisms. Since NETs were recently described, research has focused on their induction and microbicidal properties, and recently on disease involvement. However, the functional consequences of NETs interacting with other immune cells, either resident or recruited during early inflammation, have not been assessed. We therefore investigated the consequences of exposing two major APCs, macrophages (Mfs) and conventional Dendritic Cells (cDCs) to NETs. Our data revealed that at early times (30 min), both Antigen Presenting Cells (APCs) showed induction of important costimulatory molecules (CD80, CD86). Unexpectedly, however, at later times (6 and 24hours) NETs apparently triggered a cell death process in these APCs by a caspase- and Apoptosis induced factor (AIF)-dependent pathway, suggesting mitochondrial damage. By rhodamine-123 labelling we found that in both APCs, relatively prolonged exposure to NETs or their components importantly decreased the mitochondrial membrane potential. Ultrastructural analysis confirmed mitochondrial alterations in both APCs. Our results would suggest that early in inflammation, NETs can activate the two main APCs (Mfs and cDCs), but as the process continues, NETs can then initiate apoptosis of these cells through mitochondrial harm. Conceivable, this late induction of cell death in these two APCs might start limiting an ongoing inflammatory process to control it.

Robles-Gonzalez V.,ENCB IPN | Galindez-Mayer J.,ENCB IPN | Rinderknecht-Seijas N.,ESIQIE IPN | Poggi-Varaldo H.M.,Energy and Environmental Research Center
Journal of Biotechnology | Year: 2012

Mexican distilleries produce near eight million liters of mezcal per year, and generate about 90 million liters of mezcal vinasses (MV). This acidic liquid waste is very aggressive to the environment because of its high content of toxic and recalcitrant organic matter. As a result, treatment is necessary before discharge to water bodies. It is interesting, yet disturbing; verify that there is a significant gap on the treatment of MV. However, there is an abundant body of research on treatment of other recalcitrant toxic effluents that bear some similarity to MV, for example, wine vinasse, vinasses from the sugar industry, olive oil, and industrial pulp and paper wastewaters. The objective of this review is to critically organize the treatment alternatives of MV, assess their relative advantages and disadvantages, and finally detect the trends for future research and development. Experience with treatment of this set of residuals, indicates the following trends: (i) anaerobic digestion, complemented by oxidative chemical treatments (e.g. ozonation) are usually placed as pretreatments, (ii) aerobic treatment alone and combined with ozone which have been directed to remove phenolic compounds and color have been successfully applied, (iii) physico-chemical treatments such as Fenton, electro-oxidation, oxidants and so on., which are now mostly at lab scale stage, have demonstrated a significant removal of recalcitrant organic compounds, (iv) fungal pretreatment with chemical treatment followed by oxidative (O 3) or anaerobic digestion, this combination seems to give attractive results, (v) vinasses can be co-composted with solid organic wastes, particularly with those from agricultural activities and agro-industies; in addition to soil amenders with fertilizing value to improve soil quality in typical arid lands where agave is cultivated, it seems to be a low cost technology very well suited for rural regions in underdeveloped countries where more sophisticated technologies are difficult to adopt, due to high costs and requirements of skilled personnel. © 2011 Elsevier B.V.

Garcia-Canedo J.C.,CINVESTAV | Cristiani-Urbina E.,ENCB IPN | Flores-Ortiz C.M.,National Autonomous University of Mexico | Ponce-Noyola T.,CINVESTAV | And 2 more authors.
Algal Research | Year: 2016

The microalga Scenedesmus incrassatulus was cultivated in batch and fed-batch culture modes under three different nitrogen concentrations (N). Considering that nitrogen limitation results in carotenoid accumulation, main objectives of this work were to assess carotenoid concentration and the following fluorescence parameters: maximum photosynthetic efficiency (Fv/Fm), operational photosynthetic efficiency (Fq'/Fm') and the non-photochemical quenching (NPQ) at different N concentrations in the culture media, using batch and fed-batch culture modes. In all treatments, carotenoid concentration reached maximal level when N concentration in the medium was almost completely depleted. Carotenoid concentrations in fed-batch treatments were up to 3 times higher than batch culture treatments. Maximum dry weight of 4.05±0.04gL-1 and cell concentration of 8.24×107cellmL-1 was obtained using the higher N concentration in fed-batch, these values were approximately 3 times higher than the obtained in batch culture. Fv/Fm showed the highest magnitude when the initial N concentration in the culture medium was higher, for both culture modes. Results showed that the fed-batch culture of S. incrassatulus promotes a higher Fv/Fm than batch culture (up to 0.78). The application of fed-batch culture had the effect of stabilizing the values of Fv/Fm during feeding period. In all fed-batch treatments the maximum Fq'/Fm' was detected during the feeding period, which had maximum values ranging from 0.47-0.58. In fed-batch culture mode NPQ showed no direct relationship with total carotenoid concentration. ETR was higher in fed batch than in batch cultivation. In batch cultivation mode ETR had values ranging from 2 to 56μmolelectronsm-2s-1. ETR increased 6 fold in fed-batch cultivation when irradiance was increased, having values up to 610μmolelectronsm-2s-1. A good cultivation strategy for biocompound production could be the use of fed batch cultivation aimed to return nutrients like nitrogen to its initial condition. © 2015 Elsevier B.V..

Carrillo-Navas H.,National Autonomous University of Mexico | Cruz-Olivares J.,National Autonomous University of Mexico | Varela-Guerrero V.,National Autonomous University of Mexico | Alamilla-Beltran L.,ENCB IPN | And 2 more authors.
Carbohydrate Polymers | Year: 2012

Four water-in-oil-in water (W1/O/W2) double emulsions were made by adding the primary emulsion (W1/O) containing 74% (w/w) of chia essential oil, 6% (w/w) of ascorbic acid, and a 0.2 dispersed phase mass fraction (φW1/O) to aqueous solutions (W2) of mesquite gum (MG), maltodextrin DE-10 (MD) and whey protein concentrate (WPC) in different proportions (MG66-MD17-WPC17 and MG17-MD66-WPC17), and in a ratio of 1:2.12 and 1:4.12 W1/O to dry biopolymers blends solids. All the double emulsions showed type C morphologies and only slight changes in the volume-weighted mean diameter (d4,3) throughout the storage time, indicative of good stability, despite they presented bimodal size distributions, but the double emulsion formulated with a predominant proportion of MD and ratio 1:2.12 provided a higher stability against droplet coalescence. All the double emulsions displayed viscoelastic character dependent on frequency. © 2011 Elsevier Ltd. All rights reserved.

Guzman-Hernandez R.,CINVESTAV | Contreras-Rodriguez A.,ENCB IPN | Hernandez-Velez R.,ITVH | Perez-Martinez I.,CINVESTAV | And 3 more authors.
International Journal of Food Microbiology | Year: 2016

Fresh cheeses are a main garnish of Mexican food. Consumption of artisanal fresh cheeses is very common and most of them are made from unpasteurised cow milk. A total of 52 fresh unpasteurised cheeses of five different types were purchased from a variety of suppliers from Tabasco, Mexico. Using the most probable number method, 67% and 63% of samples were positive for faecal coliforms and E. coli, respectively; revealing their low microbiological quality. General hygienic conditions and practices of traditional cheese manufacturers were poor; most establishments had unclean cement floors, all lacked windows and doors screens, and none of the food-handlers wore aprons, surgical masks or bouffant caps. After analysing all E. coli isolates (121 strains) for the presence of 26 virulence genes, results showed that 9 (17%) samples were contaminated with diarrheagenic E. coli strains, 8 harboured non-O157 Shiga toxin producing E. coli (STEC), and one sample contained both STEC and diffusely adherent E. coli strains. All STEC strains carried the stx1 gene. Potential uropathogenic E. coli (UPEC) strains were isolated from 15 (29%) samples; the most frequent gene combination was fimA-agn43. Two samples were contaminated with Salmonella. The results demonstrated that unpasteurised fresh cheeses produced in Tabasco are of poor microbiological quality and may frequently harbour foodborne pathogens. Food safety authorities in Mexico need to conduct more rigorous surveillance of fresh cheeses. Furthermore, simple and inexpensive measures as establishing programs emphasizing good hand milking practices and hygienic manufacturing procedures may have a major effect on improving the microbiological quality of these food items. © 2016

Poggi-Varaldo H.M.,Environmental Biotechnology and Renewable Energies R and D Group | Munoz-Paez K.M.,Environmental Biotechnology and Renewable Energies R and D Group | Escamilla-Alvarado C.,Environmental Biotechnology and Renewable Energies R and D Group | Robledo-Narvaez P.N.,Environmental Biotechnology and Renewable Energies R and D Group | And 7 more authors.
Waste Management and Research | Year: 2014

Biohydrogen is a sustainable form of energy as it can be produced from organic waste through fermentation processes involving dark fermentation and photofermentation. Very often biohydrogen is included as a part of biorefinery approaches, which reclaim organic wastes that are abundant sources of renewable and low cost substrate that can be efficiently fermented by microorganisms. The aim of this work was to critically assess selected bioenergy alternatives from organic solid waste, such as biohydrogen and bioelectricity, to evaluate their relative advantages and disadvantages in the context of biorefineries, and nally to indicate the trends for future research and development. Biorefining is the sustainable processing of biomass into a spectrum of marketable products, which means: energy, materials, chemicals, food and feed. Dark fermentation of organic wastes could be the beach-head of complete biorefineries that generate biohydrogen as a first step and could significantly influence the future of solid waste management. Series systems show a better efficiency than one-stage process regarding substrate conversion to hydrogen and bioenergy. The dark fermentation also produces fermented by-products (fatty acids and solvents), so there is an opportunity for further combining with other processes that yield more bioenergy. Photoheterotrophic fermentation is one of them: photosynthetic heterotrophs, such as non-sulfur purple bacteria, can thrive on the simple organic substances produced in dark fermentation and light, to give more H2. Effluents from photoheterotrophic fermentation and digestates can be processed in microbial fuel cells for bioelectricity production and methanogenic digestion for methane generation, thus integrating a diverse block of bioenergies. Several digestates from bioenergies could be used for bioproducts generation, such as cellulolytic enzymes and saccharification processes, leading to ethanol fermentation (another bioenergy), thus completing the inverse cascade. Finally, biohydrogen, biomethane and bioelectricity could contribute to significant improvements for solid organic waste management in agricultural regions, as well as in urban areas. © The Author(s) 2014.

Lopez-Alvarez R.,Hospital Regional General Ignacio Zaragoza | Badillo-Lopez C.,ENCB IPN | Cerna-Cortes J.F.,ENCB IPN | Castillo-Ramirez I.,ENCB IPN | And 6 more authors.
BMC Microbiology | Year: 2010

Background. The prevalence of infections with Mycobacterium tuberculosis (MTb) and nontuberculous mycobacteria (NTM) species in HIV-infected patients in Mexico is unknown. The aims of this study were to determine the frequency of MTb and NTM species in HIV-infected patients from Mexico City, to evaluate the genotypic diversity of the Mycobacterium tuberculosis complex strains, to determine their drug resistance profiles by colorimetric microplate Alamar Blue assay (MABA), and finally, to detect mutations present in katG, rpoB and inhA genes, resulting in isoniazid (INH) and rifampin (RIF) resistance. Results. Of the 67 mycobacterial strains isolated, 48 were identified as MTb, 9 as M. bovis, 9 as M. avium and 1 as M. intracellulare. IS6110-RFLP of 48 MTb strains showed 27 profiles. Spoligotyping of the 48 MTb strains yielded 21 patterns, and 9 M. bovis strains produced 7 patterns. Eleven new spoligotypes patterns were found. A total of 40 patterns were produced from the 48 MTb strains when MIRU-VNTR was performed. Nineteen (39.6%) MTb strains were resistant to one or more drugs. One (2.1%) multidrug-resistant (MDR) strain was identified. A novel mutation was identified in a RIF-resistant strain, GAG TCG (Glu Ser) at codon 469 of rpoB gene. Conclusions. This is the first molecular analysis of mycobacteria isolated from HIV-infected patients in Mexico, which describe the prevalence of different mycobacterial species in this population. A high genetic diversity of MTb strains was identified. New spoligotypes and MIRU-VNTR patterns as well as a novel mutation associated to RIF-resistance were found. This information will facilitate the tracking of different mycobacterial species in HIV-infected individuals, and monitoring the spread of these microorganisms, leading to more appropriate measures for tuberculosis control. © 2010 Lopez-Alvarez et al; licensee BioMed Central Ltd.

PubMed | University of Veracruz, b CICATA IPN Queretaro and ENCB IPN
Type: | Journal: Preparative biochemistry & biotechnology | Year: 2016

Bacillus thuringiensis is a nonhuman pathogen bacterium that is used as a fungal and insect biocontrol agent. Because of its environmental interaction, it possesses several extracellular enzymes that are able to degrade chitin and chitosan, two of the most important polymers because of their application in numerous fields. However, in recent years, it has been observed that oligosaccharides from the enzymatic degradation of chitosan have important benefits for human health. Comparison and exploration of the production of chito-oligosaccharides from different sources of chitosan will improve the process parameters and expand the biotechnology based in these molecules. This study shows the production of chito-oligosaccharides from three different sources of colloidal chitosan and conducts a qualitative-quantitative comparison between them, using the extracellular enzyme of B. thuringiensis. We found that in the three substrates, it is possible to get a mixture of chito-oligosaccharides from dimer to hexamer in a concentration range from 0.72 to 8.09mgg

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