ESX-3 secretion system in Mycobacterium: An overview.

Mycobacteria are microorganisms distributed in the environment worldwide, and some of them, such as Mycobacterium tuberculosis or M. leprae, are pathogenic. The hydrophobic mycobacterial cell envelope has low permeation and bacteria need to export products across their structure.

LipF increases rifampicin and streptomycin sensitivity in a Mycobacterium tuberculosis surrogate.

Background: Mortality due to tuberculosis (TB) has increased due to the development of drug resistance, the mechanisms of which have not been fully elucidated. Our research group identified a low expression of lipF gene in Mycobacterium tuberculosis clinical isolates with drug resistance. The aim of this work was to evaluate the effect of lipase F (LipF) expression on mycobacterial drug resistance.

Role of and Genes in Drug-Resistant .

Tuberculosis drug resistance (DR) is a global problem that is not fully elucidated. Previously, overexpression of and genes was reported in a multidrug-resistant (MDR) isolate compared with a reference H37Rv strain. To evaluate the roles of and in DR, analysis of their regulatory and coding sequences in sensitive and resistant strains was performed, and the expression levels of their transcriptional regulators IdeR, Zur, and MntR were evaluated.

Genetic and serologic surveillance of canine (CIV) and equine (EIV) influenza virus in Nuevo León State, México.

Background: Despite the uncontrolled distribution of the Influenza A virus through wild birds, the detection of canine influenza virus and equine influenza virus in Mexico was absent until now. Recently, outbreaks of equine and canine influenza have been reported around the world; the virus spreads quickly among animals and there is potential for zoonotic transmission.

Methods: Amplification of the Influenza A virus matrix gene from necropsies, nasal and conjunctival swabs from trash service horses and pets/stray dogs was performed through RT-PCR.

Decolorization and Detoxification of Synthetic Dyes by Mexican Strains of sp.

Laccases have attracted a great deal of interest because of their remarkable ability for the degradation of synthetic dyes present in wastewaters. New laccase producing sources with robust operational and functional properties are being continuously explored. In this work, the potential for the decolorization and detoxification of synthetic dyes was evaluated in two Mexican strains of the genus .

Laccases: structure, function, and potential application in water bioremediation.

The global rise in urbanization and industrial activity has led to the production and incorporation of foreign contaminant molecules into ecosystems, distorting them and impacting human and animal health. Physical, chemical, and biological strategies have been adopted to eliminate these contaminants from water bodies under anthropogenic stress. Biotechnological processes involving microorganisms and enzymes have been used for this purpose; specifically, laccases, which are broad spectrum biocatalysts, have been used to degrade several compounds, such as those that can be found in the effluents from industries and hospitals.

Increasing Antioxidant Activity and Protein Digestibility in Phaseolus vulgaris and Avena sativa by Fermentation with the Pleurotus ostreatus Fungus.

The aim of the research was to determine the impact of fermentation with on kidney beans, black beans, and oats. The results indicate that the fungus has a positive effect on the substrates when compared to the controls. The antioxidant activity (39.

Structural studies of two thermostable laccases from the white-rot fungus Pycnoporus sanguineus.

Laccases are enzymes that have the ability to catalyze the oxidation of a wide spectrum of phenolic compounds with the four-electron reduction of molecular oxygen to water. The active site of those proteins contains four copper ions, classified into three types. Laccases are interesting enzymes for study from the point of view of their structure, function and application because of their role in lignin degradation.

Enhanced Enzymatic Activity of Laccase (from Pycnoporus sanguineus CS43) Immobilized on Sputtered Nanostructured Gold Thin Films.

Functionalization of thin films with organic ligands has been the subject of intense research due to their potential application as heterogeneous molecular nanosystems. In this work, self-assembled monolayers of thiols (16-mercaptohexadecanoic acid and 11-mercaptoundecanol) were used to bind laccase (from Pycnoporus sanguineus CS43) to nanostructured gold thin films obtained by DC sputtering. Sputtering power, sputtering pressure and substrate temperature were optimized to enhance the activity of the immobilized biomolecules.

Immobilization of laccase of Pycnoporus sanguineus CS43.

Laccase from Pycnoporus sanguineus CS43 was successfully immobilized onto Immobead-150 and Eupergit-C by covalent binding and by entrapment in LentiKats. The highest immobilization was onto Immobead-150 (97.1±1.

Genetic and serologic surveillance of rotavirus with P[8] and P[4] genotypes in feces from children in the city of Chihuahua, northern Mexico.

Rotavirus vaccine was developed using the most prominent G and P genotypes circulating in children population. Therefore, severe gastroenteritis has been reduced around the world. This study investigated the G and P rotavirus genotypes circulating in children from two hospitals in the city of Chihuahua, Mexico.

Biotransformation of Endocrine-Disrupting Compounds in Groundwater: Bisphenol A, Nonylphenol, Ethynylestradiol and Triclosan by a Laccase Cocktail from CS43.

The biodegradation of organic compounds present in water at trace concentration has become a critical environmental problem. In particular, enzymatic oxidation by fungal laccases offers a promising alternative for efficient and sustainable removal of organic pollutants in water. In this work, the biocatalytic ability of laccases from the CS43 fungus was evaluated.

Enhanced production of thermostable laccases from a native strain of Pycnoporus sanguineus using central composite design.

The production of thermostable laccases from a native strain of the white-rot fungus Pycnoporus sanguineus isolated in Mexico was enhanced by testing different media and a combination of inducers including copper sulfate (CuSO4). The best conditions obtained from screening experiments in shaken flasks using tomato juice, CuSO4, and soybean oil were integrated in an experimental design. Enhanced levels of tomato juice as the medium, CuSO4 and soybean oil as inducers (36.

Sphingomyelinase activity of Trichomonas vaginalis extract and subfractions.

Trichomoniasis is one of the most common acute sexually transmitted curable diseases, and it is disseminated worldwide generating more than 170 million cases annually. Trichomonas vaginalis is the parasite that causes trichomoniasis and has the ability to destroy cell monolayers of the vaginal mucosa in vitro. Sphingomyelinases (SMase) are enzymes that catalyze the hydrolysis of sphingomyelin into ceramide and phosphorylcholine.

Entamoeba histolytica: soluble and membrane-associated neutral sphingomyelinase-C and other unidentified esterase activity.

Sphingomyelinase (SMase) activity was measured in Entamoeba histolytica particulate and soluble subcellular fractions. The effects on SMase of incubation time, total protein concentration, pH, and several divalent cations were determined. SMase-C and other unidentified esterase activity were detected in soluble and particulate fractions.

Inositol phosphoceramide synthase is a regulator of intracellular levels of diacylglycerol and ceramide during the G1 to S transition in Saccharomyces cerevisiae.

We recently reported that DAG (diacylglycerol) generated during sphingomyelin synthesis plays an important role in protein kinase C activation and cell proliferation in Madin-Darby canine kidney cells [Cerbon and Lopez-Sanchez (2003) Biochem. J. 373, 917-924].

Lead and calcium transport in human erythrocyte.

In this paper we report the lead (Pb) and calcium (Ca) uptake by erythrocyte ghosts. In both cases the transport was carried out by a passive transport system with two kinetic components (Michaelis-Menten and Hill). Pb and Ca were capable of inhibiting the transport of the other metal in a non-competitive way.

Effect of lead on the calcium transport in human erythrocyte.

In this paper we study the calcium uptake in the erythrocyte, a non-excitable cell. This uptake is performed through a passive transport system with two kinetic components (Michaelis-Menten and Hill). The uptake of calcium seems to be driven by voltage through its electrophoretical effect.

Lead: intestinal absorption and bone mobilization during lactation.

The aim of this study was to examine lead (Pb) intestinal absorption, its mobilization and redistribution during lactation in rats chronically exposed to lead. Lead and calcium (Ca) concentrations were measured in blood, milk, femurs, liver and kidney samples obtained from pregnant and lactating mother rats which were subjected to different schedules of exposure to Pb: 158 days before and during lactation (group A), 144 days before lactation (group B) and 14 days only during lactation (group C). Results were compared to those of non-pregnant but Pb-exposed matched rats and non-exposed control rats.

Evolution of lead toxicity in a population of children.

A 3 years study was conducted to determine the evolution of blood lead concentrations (PbB) and free erythrocyte protoporphyrins (FEP) as indicators of absorption and biochemical damage in children (7-12 years old) living within one kilometer of a metallurgic factory that processes lead in Torreón, Coahuila, México. In addition, neuromuscular conduction velocity, motor coordination and IQ where determined as indicators of physiological damage. During this period of time the children showed increased lead blood concentrations of 19.

Mechanisms of the toxic effect of lead. I. Free lead in erythrocyte.

In this work, a selection of children was examined based on their free erythrocyte protoporphyrin (FEP) and total blood lead (PbB) contents. Two groups with clear differences in lead sensibility were selected. One group with high FEP levels (deep lead alteration), named "normal," and one group with low FEP levels (discrete lead alteration), named "lead tolerant," and both with similar PbB concentration, were formed.

Anionic phospholipids in the control of the membrane surface potential in Escherichia coli: their influence on transport mechanisms.

1. Phosphatidylserine (PS)-rich Escherichia coli cells were utilized to investigate the role of anionic phospholipids on membrane surface potential and their effect upon active transport mechanisms. 2.