Microbiota gastrointestinal y síndrome de intestino irritable

We thank García-Mazcorro et al.1 for their interest and comments on completely agree with them concerning the term intestinal «flora». Microbiota is the correct word, defined as the community of living microorganisms residing in a determined ecological niche, and we use it, not only in the title, but throughout the article (79 times to be exact), whereas the less precise but commonly used flora is employed only 5 times.2 Secondly, the 16S ribosomal RNA (rRNA) gene is one of the components of the small subunit (30S) of the ribosome and is present in all bacteria and archaea. It is the genetic marker used in bacterial phylogenetic analysis and is widely used in an endless number of studies. This gene sequence is approximately 1,550 bp long and is composed of 9 highly variable regions or hypervariable regions flanked by constant regions. The differences in sequencing of these hypervariable regions make it possible to taxonomically identify the bacteria present in study samples (for example, in stools and intestinal mucosa).3 The «rrs» gene, also known as 16S ribosomal DNA or 16S rDNA, as mentioned in table 3 of our article, encodes 16S rRNA. Even though there are limitations in sequencing based on 16S rRNA, it continues to be the gold standard due to the extensive databases based on this marker. Illumina belongs to the «next generation» sequencing technologies that are limited by the length of the sequences they can provide, and so specific regions of the 16S rRNA gene must be selected in the analysis.3 Other sequencing strategies and equipment currently exist that were designed for completion and correction. Thirdly, the inability to absolutely establish the microbiota that is characteristic of IBS due to the factors mentioned by García-Mazcorro et al. is a fundamental aspect of our review.2 In fact, that was why we reached the conclusion that even though there is evidence that the intestinal microbiota is different in persons with IBS from that of normal subjects (level 3b evidence, grade B recommendation), it is not possible to establish a microbial composition that is specific for this disorder (level 3b evidence, grade B recommendation).2 On the other hand, we agree that the taxonomic levels found were not mentioned in some cases, but some of the studies reviewed only reported the differences in microbial groups. And finally, we agree that our already extensive review fell short of analyzing the use of probiotics, prebiotics, and even synbiotics, in the treatment of IBS, but we felt these topics should be the subject of another review. As a matter of fact, a very recent systematic review of the literature has reported that probiotics were superior to placebo due to a lower frequency of IBS symptom persistence (55.8% vs. 73.1%).4 In addition, probiotics were shown to be superior to placebo in the improvement of overall symptoms, abdominal pain, subjective abdominal bloating, and flatulence. Specifically, it was Bifidobacterium spp that showed a tendency toward the improvement of overall symptoms and abdominal pain, but determining which strain(s) will be the effective one(s) has yet to be established. The authors also found that there were very few studies on prebiotics and synbiotics.4 Another review found that B. infantis 35624 was effective in improving subjective bloating in IBS in general and B. animalis DN-173010 in patients with constipation predominant IBS (IBS-C).5 Furthermore, the relation between diet and the microbiota should also be analyzed. For example, low FODMAP (Fermentable Oligosaccharides Disaccharides, Monosaccharides, And Polyols) diets that improve IBS symptoms also appear to reduce the concentration and proportion of bifi-dobacteria in stools determined through fluorescence in situ hybridizatio

Evaluation of aflatoxin and fumonisin co-exposure in urine samples from healthy volunteers in northern Mexico

Aflatoxins (AF) and fumonisins (FB) are common contaminants of maize and have been associated with cancer, immune suppression, and growth stunting. In this work, AFM(1) and FB(1) were measured in urine samples of healthy volunteers from the metropolitan area of Monterrey, Mexico, while AF and FB were detected in foods collected near the sampling zone. Urine samples from 106 adults were analyzed using ultra-performance liquid chromatography-tandem mass spectrometry and toxins in foods were measured by fluorometry. The mean value of AFM(1) and FB(1) was 4.3 pg/mg creatinine from 76 samples (72 %), and 50 pg/mg creatinine from 75 samples (71 %), respectively. More than half of the samples (n = 56, 53 %) had detectable levels of both AFM(1) and FB(1). No differences in toxin levels were found between males and females or between age groups, but AFM(1) and FB(1) levels were higher (p < 0.01) when detected as a single exposure compared to co-exposed. Some significant results were found when comparing AFM(1) and FB(1) levels among groups of people assigned to levels of food consumption. Food samples had average concentrations of 5.3 μg/kg for AF and 800 μg/kg for FB. The results showed that co-exposure to AF and FB is common in the metropolitan area of Monterrey

Insoluble chitosan complex as a potential adsorbent for aflatoxin B1 in poultry feed

As a class of secondary metabolites or toxins produced by fungi, aflatoxins can poison humans and animals; among them, aflatoxin B1 (AFB1) is the most dangerous one owing to its carcinogenic and mutagenic properties that increase risks for hepatocellular carcinoma in humans; hence, adsorbents such as smectites are commonly included in poultry feed to mitigate their effects. In this study, chitosan was crosslinked with sodium dodecyl sulfate (SDS) to form an insoluble polymer complex that is stable at the relevant physiological pH levels. The characterization via Fourier transforms infrared spectroscopy revealed the interaction between the sulfate groups of the SDS and the amine group of chitosan (1,016 and 819 cm−1); this result was further confirmed by the X-ray diffraction patterns with a change in the crystalline structure of the chitosan-insoluble complex (2θ = 4.76°, 7°, and 22°). The morphology of the chitosan-insoluble complex obtained using a field emission scanning electron microscope (FE-SEM) revealed that particles were slightly porous. After characterization, the performance of the chemically modified polymer complex was evaluated as an adsorbent for AFB1 and compared with those of the unmodified chitosan, soluble chitosan complex, and commercial montmorillonite clay binder. In addition, the polymer complex was investigated as an adsorbent in an in vitro model for the poultry gastrointestinal system. Sequestration of AFB1 by a chemically modified polymer complex was 93.4%, equivalent to that of commercial montmorillonite clay (99.5%). However, these treatments also sequestered microminerals, particularly selenium and iron. This pH-stable, high-capacity adsorbent could be used in poultry feed to reduce the uptake of AFB1

Implementación del diagnóstico de mycoplasma gallisepticum y mycoplasma synoviae mediante PCR-RFLP en aves de producción / Alicia Guadalupe marroquín Cardona.

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Characterization, influence and manipulation of the gastrointestinal microbiota in health and disease

The gastrointestinal tract harbors trillions of microorganisms that are indispensable for health. The gastrointestinal microbiota can be studied using culture and molecular methods. The applications of massive sequencing are constantly increasing, due to their high yield, increasingly accessible costs, and the availability of free software for data analysis. The present article provides a detailed review of a large number of studies on the gastrointestinal microbiota and its influence on human health; particular emphasis is placed on the evidence suggesting a relationship between the gastrointestinal microbial ecosystem and diverse physiological and immune/inflammatory processes. Discussion of the articles analyzed combines a medical approach and current concepts of microbial molecular ecology. The present revision aims to be useful to those interested in the gastrointestinal microbiota and its possible alteration to maintain, re-establish and enhance health in the human host

Detoxification of Aflatoxin-Contaminated Maize by Neutral Electrolyzed Oxidizing Water

Aflatoxins, a group of extremely toxic mycotoxins produced by Aspergillus flavus, A. parasiticus and A. nomius, can occur as natural contaminants of certain agricultural commodities, particularly maize. These toxins have been shown to be hepatotoxic, carcinogenic, mutagenic and cause severe human and animal diseases. The effectiveness of neutral electrolyzed oxidizing water (NEW) on aflatoxin detoxification was investigated in HepG2 cells using several validation methodologies such as the 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide assay, the induction of lipid peroxidation, the oxidative damage by means of glutathione modulation, the Ames test and the alkaline Comet assay. Our results showed that, after the aflatoxin-contaminated maize containing 360 ng/g was soaked in NEW (60 mg/L available chlorine, pH 7.01) during 15 min at room temperature, the aflatoxin content did not decrease as confirmed by the immunoaffinity column and ultra performance liquid chromatography methods. Aflatoxin fluorescence strength of detoxified samples was similar to untreated samples. However, aflatoxin-associated cytotoxicity and OPEN ACCESS Toxins 2015, 7 4295 genotoxicity effects were markedly reduced upon treatment. According to these results, NEW can be effectively used to detoxify aflatoxin-contaminated maize

Compuestos fenólicos y capacidad antirradicalaria de cinco accesiones silvestres de Portulaca oleracea L.

Purslane (Portulaca oleraceaL.) is a species recognized for its high levels of bioactive compounds, among which the compounds with antioxidant properties stand out. The objective of the work was to determine the variation of phenolic metabolites and their antiradical capabilities inwild accessions of P. oleracea. The research was conducted with samples from five municipalities in Tamaulipas, Mexico collected in October 2018. Thecontents of total phenolic compounds (CFT) and free radical scavenging capacity against ABTS (2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulfonic)acid) and DPPH (2,2-diphenyl-1-picrylhydracyl)were determined. Extractions were made from vegetative parts using three solvents: acetone, water and ethanol. The accession of the localities of Abasolo and Padilla were the ones that had the highest amount of CFT with 5.8938±0.03 and 5.3742±0.11 mEAGg-1PS, respectively, using water in the extraction. Regarding the free radical scavengingcapacity against ABTS, the accession of Abasolo and Jiménez recorded the highest values, with 3.27±0.06 and 3.2226±0.04 mM ETg-1PS. Regarding thelevel against DPPH radicals, the accession of Abasolo was the highest with 2.0204±0.05 mM ETg-1PS,using water in the extraction. Water was the best solvent for the extraction of the determined contents. Heterogeneity was observed in the composition and levels of the parameters evaluated among the accessions. Wild P. oleraceaaccessions represent reservoirs of phenolic compounds and free radical scavenging capacity, including cultivated and wild varietiesLa verdolaga (Portulaca oleracea L.) es una especie reconocida por sus altos niveles de compuestos bioactivos, entre los que destacan los compuestos antioxidantes y su capacidad colectora de radicales libres. El objetivo del trabajo fue determinar la variación de metabolitos fenólicos y sus capacidades antirradicalarias en accesiones silvestres de P. oleracea. La investigación se realizó con muestras provenientes de cinco municipios de Tamaulipas, México recolectadas en octubre 2018. Se determinaron los contenidos de compuestos fenólicos totales (CFT) y capacidad colectora de radicales libres contra ABTS (ácido 2,2'-azino-bis- (3-etilbenzotiazolina-6-sulfónico)) y DPPH (2,2-difenil-1-picrilhidracilo). Las extracciones se realizaron de partes vegetativas usando tres solventes: acetona, agua y etanol. La accesión de las localidades de Abasolo y Padilla fueron la que presentaron mayor cantidad de CFT con 5.8938±0.03 y 5.3742±0.11 mEAG/g PS, respectivamente, usando agua en la extracción y la accesión de Padilla fue la de menor contenido con 1.2409±0.45 mEAG/g PS usando etanol para la extracción. Respecto a la capacidad colectora de radicales libres contra ABTS y DPPH la accesión de Abasolo registró los valores más altos, con 3.2700±0.06 y 2.0204±0.05 mM ET/g PS, respectivamente, usando agua en la extracción. El agua fue el mejor solvente para la extracción de todos los contenidos determinados. Se observó una heterogeneidad en la composición y niveles de los parámetros evaluados entre las accesiones. Las accesiones silvestres de P. oleracea representan reservorios importantes de compuestos fenólicos y capacidad colectora de radicales libres, los cuales deben caracterizarse a fondo para apoyar el aprovechamiento de la especie, incluyendo las variedades cultivadas y silvestres