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Introduction: Clostridiodes difficile and Paeniclostridium sordellii are Gram-positive, anaerobic and sporeforming bacteria. C. difficile is the leading cause of antibiotic-associated diarrea and P. sordellii is mainly reported in infections in pregnant women with toxic shock syndrome and in other infections in animals. Glycosyltransferase toxins are the main virulence factors of both bacteria, C. difficile produces toxins A and B (TcdA and TcdB) while P. sordelli produces lethal (TcsL) and hemorrhagic (TcsH) toxins. Objective: To provide a description of the mechanisms of action on cell adhesions of bacterial toxins with glycosyltransferase activity and their association with infections produced by C. difficile and P. sordellii. Methods: A review was carried out which sought to meet the following parameters: Only experimental articles published between 2000 and 2021 in Spanish or English language. These articles were obtained from Google Scholar, Science Direct and Pubmed databases. Furthermore, the following keywords were included: Clostridium difficile, Clostridium sordellii, Clostridiodes, Paeniclostridium, cellular adhesion (focal, tight-adhesion), or toxins. Results: TcdA, TcdB, TcsL and TcsH belong to the family of large glycosylating toxins, which have glycosiltransferase activity over monomeric GTPases. Eukaryotic cells maintain their structure and conformation thanks to cell adhesions, which include focal (extracellular cell-matrix) and tight (cell-cell) adhesion. The mechanism of action of these clostridial toxins is that they alter focal adhesion proteins such as Src, FAK, and paxillin, and for tight adhesion such as ZO1, occludins, and the E-cadherin-catenin complex. This is due to mechanisms dependent on the glycosylation of GTPases and others that are not. The alteration of these adhesions interferes with the correct function of the epithelial barrier. As a result of these alterations induced by C. difficile toxins in eukaryotic cell junctions, a disruption of the intestinal epithelial barrier, increased inflammation, and permeability are observed, which exacerbates the clinical symptoms with complications such as pseudomembranous colitis. P. sordellii mainly affects the pulmonary epithelium, by increasing its vascular permeability allowing the passage of fluids to the lung parenchyma, leading to anoxia and even death by altering cellular adhesions. Conclusion: The information available is not comprehensive, a fact that emphasize the importance to continue researching on the subject. It is still unknown whether there are other proteins that are altered, as well as the mechanism by which they are altered. The study of different TcdBs is important due to the high variability of strains, which influences their expression, their specificity as a substrate or receptor, among other important aspects in the pathogenesis of this disease. All this to better understand the pathogenesis of clinical pictures by bacteria producing large clostridial toxins with glycosyltransferase activity. [ABSTRACT FROM AUTHOR]

Fungi of the Trichoderma genus have been widely studied for their mycoparasitic characteristics that allow the generation of biological control products. In addition, some of them promote plant growth. Currently, there are over 300 species divided into 8 clades or lineages. Despite such diversity, few species have been reported in Mexico, and there is not representativeness of every clade. Here, we present the identification of the 2IG2102 strain of T. brevicompactum based on analysis of 3 phylogenetic markers, as well as its characterization as antagonist towards 2 Fusarium fungi, and it also boosts tomato and cucumber seed germination. Trichothecene biosynthesis might be a mechanism required to inhibit phytopathogens growth and in parallel affect the post-germinative growth of tomato. This is the first report of a Trichoderma belonging to the clade 6 isolated in Mexico, that displays capacity to antagonize fungi and it might produce trichothecenes for biological control. [ABSTRACT FROM AUTHOR]

Se determina por primera vez la presencia de Dinophysistoxin-1 (DTX-1) como una possible toxina asociada a la ciguatera en aguas de la costa norte de La Habana, fue medida por cromatografía líquida de alta resolución (HPLC-FLD). Prorocentrum lima (Dinophycea, Prorocentrales), en asociación con Padina. sp es la especie productora de esta toxina. Fueron obtenidos conteos de las células del medio natural 1675 cell.g -1 peso húmedo de macroalgas) y de las cultivadas en medio K (65 000 Cell/ mL). Los resultados de los extractos de las toxinas de las células cultivadas y las del medio natural mostraron concentraciones de 7.15 pg DTX-1 /cél y 4.2 pg DTX-1/cél respectivamente. Es altamente probable la presencia y distribución potencial de DTX-1 NW de Cuba considerando que las condiciones ambientales son muy similares.

Introducción. La toxina (apitoxina) producida por abejas (Apis mellifera), es un producto con expectativas importantes en la industria médica, debido al uso terapéutico en diversas enfermedades. Objetivo. El objetivo del presente estudio fue estimar el potencial de producción anual de apitoxina, recolectada mediante un equipo automatizado funcionando con impulsos eléctricos de 10 s de duración y un voltaje de 12 v. Materiales y métodos. Se utilizaron cinco colmenas de un apiario localizado en Irapuato, Guanajuato, México, donde se cosechó la apitoxina de agosto de 2016 a junio de 2017, a intervalos quincenales durante un lapso de 20 min por vez, y se suspendió la colecta en aquellos periodos con flujos abundantes de néctar, con la finalidad de no afectar la producción de miel. Resultados. De acuerdo con las condiciones en las que se desarrolló este estudio, el promedio (± desviación estándar) por cosecha con extracción quincenal fue de 52,41±13,83 mg.colmena-1, producción que se incrementó a 62,48±1,37 mg.colmena-1, al considerar solo colonias con bajos niveles de infestación de Varroa destructor. Conclusión. La región apícola donde se desarrolló esta investigación presentó potencial para la producción de apitoxina, proponiéndose como un producto apícola adicional que permite incrementar la rentabilidad del apiario.

As Doenças Transmitidas por Alimentos (DTA) são síndromes constituídas de anorexia, náuseas, vômitos e/ou diarreia, acompanhadas ou não de febre, porém não se limitam a sintomas digestivos, podendo ocorrer manifestações extraintestinais. São atribuídas à ingestão de alimentos ou água contaminados, podendo ser causadas por agentes físicos, químicos ou biológicos, sendo este último grupo representado pelos parasitas, vírus e, em especial, as bactérias, que podem atuar diretamente sob o organismo do indivíduo ou através da produção de toxinas. A ocorrência de DTA é um grave problema em saúde pública, uma vez que estas apresentam um impacto significativamente negativo tanto no contexto social, em decorrência das vítimas que sofrem seus agravos, quanto no econômico, onde grandes perdas são geradas nos ramos da indústria, comércio e turismo. Apesar disso, para muitas pessoas este é um assunto tratado de forma irrelevante ou até mesmo para alguns ainda desconhecido, o que se torna um agravante deste problema. O objetivo deste estudo é fazer uma revisão apresentando o panorama das DTA no Brasil, os aspectos gerais relacionados a estas doenças e as principais bactérias envolvidas em surtos no país.

Due to the harmful effects associated with the presence of microcystin-LR (MC-LR) cyanotoxin, photo-degradation assays were performed in natural and distilled water using the combined action of ultraviolet (UV) radiation and hydrogen peroxide (H2O2). The effect of H2O2 content and UV irradiance was evaluated and optimized using a multilevel factorial design in distilled water spiked with 20 μg L-1 MC-LR. The coupled UV/H2O2 system under optimal operating conditions (0.63 mW cm-2 irradiance and 30 mg L-1 H2O2) was more effective than the individual action of UV irradiance or H2O2 content for 30 min of treatment time, since a reduction of 97.78% of MC-LR was achieved. After optimizing the operating conditions, they were applied for natural water, obtaining MC-LR removals similar to those achieved with distilled water (99.59 and 99.73%, respectively), reaching a final MC-LR concentration in both matrices well below the maximum recommended limit established by WHO for MC-LR in drinking water, fixed at 1 μg L-1. 15 mg L-1 of H2O2 were also tested, and although 98.08% of MC-LR elimination was found for a reaction time of 60 min, WHO advisable limit was not surpassed. The UV/H2O2 process could be considered as an alternative to the conventional processes water facilities are operating with to tackle the problem of fresh water pollution with cyanotoxins, providing the accomplishment of the whole set of water quality standards included in the legislation. [ABSTRACT FROM AUTHOR]

Copyright of Compendium of Veterinary Sciences / Compendio de Ciencias Veterinarias is the property of Facultad de Ciencias Veterinarias de la Universidad Nacional de Asuncion and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this work, the poison of Phymactis papillosa collected in Ancón bay has been studied biochemically. The venom was obtained by hypotonic shock and then lyophilized. Electrophoretic analysis of the soluble poison showed the presence of 5 protein bands with molecular weights between 5 and 25.1 kDa. The soluble venom was fractionated by filtration chromatography on a Sephadex G-50 column, yielding four protein peaks (I, II, III and IV). In the soluble venom and collected fractions was measured protease activity, phospholipase, hyaluronidase, acid phosphatase and alkaline phosphatase; as well as hemolytic and neurotoxic activity. Proteolytic activity on casein was found in the soluble venom and peaks I and III. Was not detected phospholipase activity, hyaluronidase, acid phosphatase and alkaline phosphatase. Hemolytic activity on human red cells tested, was found in the soluble venom and peak II. Finally, the soluble venom as the peak III showed be neurotoxic when injected into white mice intraperitoneally. It is concluded that the soluble venom of P. papillosa has proteolytic, hemolytic and neurotoxic activity.

Background: Toxinology is a sub-field of toxicology dedicated to studying toxins produced by animals, plants and, microorganisms. In Colombia, during the last thirty years, this area has been mainly investigated by Ophidism/Scorpionism Program of Universidad de Antioquia. However, some other research groups have also contributed to our knowledge of venoms and toxins, as well as their related effects and treatments. Objective: to highlight the most significant findings in toxinology made by the Ophidism/Scorpionism Program and other research groups in Colombia. Methods: 119 papers dealing with the history of ophidiology and toxinology in Colombia were collected and analyzed. Results: some useful terms are described to understand toxinology and its scope. Also, a brief history of ophidiology is presented, spanning from the discovery of America until present-day findings. Finally, an overall description of several results related to toxin isolation, characterization, antivenoms, clinical trials, description of new species, proteomic and transcriptomic, among others. The nineteens were characterized by the study of snakebites, their clinic manifestations, and the use of antivenoms. In addition, the ethnopharmacological studies of medicinal plants used in snakebite treatments began to be explored. The 2000s included the newly ethnopharmacology, toxin isolation, clinical trials, inhibitor studies, scorpion venom characterization, and scorpion stings features. Finally, from 2010 until today, proteomic and transcriptomic gave the most important findings. Conclusions: Toxinology works in Colombia have contributed to our knowledge about endemic species, clinical manifestations of snakebite and scorpion stings, and the development of new therapeutic agents. However, we invite Colciencias and other funding agencies to assign more resources to support a higher number of researchers in this field, since snakebite is considered a neglected tropical disease by the World Health Organization, which needs more attention from governments and scholars. Finally, the venoms of some species and their possible mode of action are still unknown to us. Besides, given the complexity of venoms, we are not yet aware of the potential use of toxins in current biomedicine. Thus, studies in toxinology must continue. [ABSTRACT FROM AUTHOR]

Copyright of Tropical Grasslands / Forrajes Tropicales is the property of International Centre for Tropical Agriculture - CIAT and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of RGO: Revista Gaúcha de Odontologia is the property of RGO: Revista Gaucha de Odontologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Antecedent: A quick and specific detection of biological warfare agent is the keystone in several fields like environmental control, clinic diagnostic, food industry, security and defence. The specificity of antigen-antibody binding is used in a multitude of biosensors like biological warfare-agent detection equipment. However, how the antibody is attached to the biosensor surface, in terms of density, orientation and stability, will determine the diagnosis capability of the device. Aim: the development of antibodies immobilization proceedings in planar surface for an efficient antigen-antibody reaction to be used in immunological sensing devices. Material and Methods: three immobilization methods of fluorescein labelled antibody were assayed on Zprobe membrane: passive adsorption, covalent bond by glutaraldehyde, well-oriented immobilization by the intermediate protein A/G. Bovine serum albumin labelled with R-phycoerytrin was selected as toxin surrogate. 0,5 % glutaraldehyde and A/G chimeric protein (5 and 10 µg) were used as immobilization reactive. Results: immobilized antibody retention during the immunocapture process was similar between all the assayed immobilization methods. The immobilized antibody density by glutaraldehyde was higher than that by protein A/G. However, with regard to the antigenic immune-capture efficiency antibody immobilization by glutaraldehyde was the less efficient than immobilization by protein A/G. Conclusions: Antibody immobilization by glutaraldehyde, in spite of increasing the retained antibody density on the Zprobe membrane, interferes in the antigenic immunodetection whereas the intermediate protein A/G improves it, allowing a very efficient immunocapture system with less antibody density. [ABSTRACT FROM AUTHOR]

ABSTRACT: Entomopathogenic fungi are important biological control agents throughout the world, have been the subject of intensive research for more than 100 years, and can occur at epizootic or enzootic levels in their host populations. Their mode of action against insects involves attaching a spore to the insect cuticle, followed by germination, penetration of the cuticle, and dissemination inside the insect. Strains of entomopathogenic fungi are concentrated in the following orders: Hypocreales (various genera), Onygenales (Ascosphaera genus), Entomophthorales, and Neozygitales (Entomophthoromycota).

En Galicia existen abastecimientos que captan agua de embalses con crecimiento de cianobacterias con riesgo de producir toxinas. Las estaciones de tratamiento de agua potable (ETAP) de estos abastecimientos deben tener tratamientos adecuados y estar sometidas a mantenimientos. Las guías de la OMS hacen recomendaciones sobre los tratamientos más convenientes para eliminar las microcistinas. La Consellería de Sanidade elaboró conjuntamente con los organismos de cuenca un protocolo de actuación frente a estos eventos. Para este estudio se han identificado 4 embalses y 5 plantas de tratamiento. Se han evaluado los tratamientos de las plantas, los mantenimientos que se realizan a las ETAP y los resultados de las toxinas sestónicas y disueltas analizadas por el laboratorio de Salud Pública de Galicia en los embalses cerca del punto de captación, antes de las plantas de tratamiento y después de ellas durante el bienio 2013-2014.

El presente trabajo es una revisión bibliográfica que abarca el agente etiológico, sus principales características, mecanismos y factores que condicionan la patogenicidad, la patogenia y su utilización en la guerra bacteriológica y en el bioterrorismo a lo largo de la historia.

Brazil has a history of blooms and contamination of freshwater systems by cyanobacterial toxins. The monitoring relevance of toxins from cyanobacteria in reservoirs for public supply is notorious given its high toxicity to mammals, included humans beings. The most recurrent toxins in Brazilian water bodies are microcystins (MC). However, the recent record of cylindrospermopsin (CYN) in northeastern Brazil, Pernambuco state, alerts us to the possibility that this could be escalating. This study reports occurrence of MC and CYN, quantified with ELISA, in 10 reservoirs, devoted to public drinking supply in northeastern Brazil. The composition and quantification of the cyanobacteria community associated with these water bodies is also presented. From 23 samples investigated for the presence of MC, and CYN, 22 and 8 out were positive, respectively. Considering the similarity of the cyanobacteria communities found in reservoirs from Pernambuco, including toxin-producing species associated to MC and CYN, we suggest that geographic spreading can be favored by these factors. These issues emphasize the need for increased monitoring of MC and CYN in drinking supply reservoirs in Brazil.

The symptoms of the ophidian envenoming caused by snakes of the genera Porthidium and Bothrops, are the result of the combination of effects of the various toxins and enzymes that make up the venom of the species involved. The composition of snake venoms is subject to great variability, which is a very important aspect to conside, in the investigation of its composition, toxic efects, biochemical and haemostatic effects, as well as in the management of the clinical picture of envenomed patients and in the development of effective antivenoms. Each venom of a viper species constitutes a unique mixture of peptides and proteins chosen by natural selection to act on the vital systems of its prey. These qualitative and quantitative differences between venoms exist at the level of families, genera, species and even intra-species. [ABSTRACT FROM AUTHOR]

El presente trabajo informa sobre características bioquímicas, actividad hemolítica, citotóxica y citolítica de tres fracciones del veneno de la anémona de mar Anthothoe chilensis. Los tentáculos de 78 ejemplares de A. chilensis, provenientes de la Isla Cabinza-San Lorenzo, Lima, fueron procesados obteniendo un filtrado, el cual se fraccionó por precipitación con tres puntos de saturación con acetona fría: I (20%), II (50%), III (80%). El filtrado mostró una concentración proteica de 1,8 mg/mL. Las pruebas de detección de carbohidratos totales demostraron la presencia de 1,401 mg de glucosa/ml de solución en el filtrado; mientras que la electroforesis en gel de poliacrilamida en presencia de dodecil sulfato de sodio (PAGE-SDS) evidenció proteínas de 14 a 94 kDa, de las cuales la mayor parte fueron glicoproteínas. Se encontró actividad hemolítica sobre eritrocitos humanos en las fracciones I y II. La fracción III tuvo la actividad fosfolipásica más alta. Las tres fracciones tuvieron una ligera actividad proteolítica sobre caseína siendo la más activa la fracción I. Los efectos citotóxico y citológico fueron evaluados aplicando el Ensayo de Toxicidad en Embriones de Erizo de mar (SET). Las anormalidades morfológicas fueron evaluadas a las 48 horas de desarrollo. Las anormalidades citológicas fueron evaluadas en el estadio de gástrula tardía. Las tres fracciones acetónicas produjeron daños citotóxicos y citológicos importantes en los embriones de erizo de mar. Los efectos sobre los embriones fueron retrasar su desarrollo y producir anomalías morfológicas como lisis de blástulas y exogastrulación. Los daños citológicos observados fueron núcleos heteropicnóticos, núcleos gigantes y espacios celulares anormales. La fracción II fue la más citotóxica produciendo una mortalidad de 75,52 ± 5,5% en los primeros estadíos con 1,0 μg/mL. La fracción I produjo el mayor porcentaje de anomalías en los embriones supervivientes 64,15 ± 4,2 % con 1,3 μg/mL. La fracción III fue la menos tóxica.

In this study, we developed a bioassay to quantify the ricin toxin content of castor bean seeds. Existing quantification methods do not always reflect actual toxicity of the seeds analyzed, which may present lower ricin content even though they are more toxic than seeds presenting a higher content of ricin. This is because these methods actually measure the addition of ricin RCA, which is a compound less toxic than pure ricin. We decided to use in this study, the nematode Caenorhabditis elegans, which has been widely used by the pharmaceutical industry. We tested two strains of C. elegans using different methods in 8 experiments. We examined 4 methods of extracting the ricin complex and 3 methods of exposing the nematodes. Among the nematode strains and ricin extraction methods tested, we concluded that the best strain for testing ricin toxicity was the strain called N2 and that the best method for ricin extraction was a rotating bath followed by centrifugation and exposing the nematodes in 24 well plates with a solution of nematodes extracted from the media with destilated waterexposing the nematodes in 24-well plates This method is inexpensive, quick and adequate for the selection of offspring with lower RIP content.Foi desenvolvido um bioensaio para quantificar o teor de ricina nas sementes de mamona. Os métodos de quantificação existentes não refletem a toxidez real das sementes analizadas, que pode mostrar um resultado de menor teor de ricina e ainda assim ser mais toxico do que as sementes que apresentaram teores maiores. Isto ocorre por que estes métodos medem alem da ricina a RCA, que é um composto menos tóxico que a ricina pura. Foi decidido utilizar neste estudo o nematoide Caenorhabditis elegans, que tem sido amplamente utilizado na industria farmacêutica. Foram testadas duas estirpes de C.elegans usadas em diferentes métodos contando com 8 experimentos distintos. nós examinamos 4 métodos de extração de ricina e 3 métodos de exposição do nematóide à ricina. Foi concluído que a melhor estirpe para testar ricina foram as estirpes chamadas de N2 e o melhor método de extração da toxina foi o do banho maria seguido pela centrifugação e o melhor método de exposição dos nematóides foi o que conta com uma placa de 24 poços onde o nematóide suspenso em água destilada são expostos a toxina. Este é um método barato, rápido e adequado para seleção de materiais com baixo teor de RIP.

Clostridium perfringens is an anaerobic Gram-positive bacterium known as common pathogen for humans, for domestic and wildlife animals. Although infections caused by C. perfringens type C and A in swine are well studied, just a few reports describe the genetic relationship among strains in the epidemiological chain of swine clostridioses, as well as the presence of the microorganism in the slaughterhouses. The aim of the present study was to isolate C. perfringens from feces and carcasses from swine slaughterhouses, characterize the strains in relation to the presence of enterotoxin, alpha, beta, epsilon, iota and beta-2 toxins genes, using polymerase chain reaction (PCR) and comparing strains by means of Pulsed field gel electrophoresis (PFGE). Clostridium perfringens isolation frequencies in carcasses and finishing pig intestines were of 58.8% in both types of samples. According to the polymerase chain reaction assay, only alfa toxin was detected, being all isolates also negative to enterotoxin and beta2 toxin. Through PFGE technique, the strains were characterized in 35 pulsotypes. In only one pulsotype, the isolate from carcass sample was grouped with fecal isolate of the same animal, suggesting that the risk of cross-contamination was low. Despite the high prevalence of C. perfringens in swine carcasses from the slaughterhouses assessed, the risk of food poisoning to Brazilian pork consumers is low, since all strains were negative to cpe-gene, codifying enterotoxin.Clostridium perfringens é uma bactéria Gram positiva anaeróbica, conhecida por infectar os seres humanos, animais domésticos e de vida selvagem. Apesar de as infecções causadas por C. perfringens tipo C e A em suínos serem bastante estudadas, poucos relatos descrevem a relação genética entre as linhagens envolvidas na cadeia epidemiológica da clostridiose suína, bem como a presença do microorganismo em abatedouros. O objetivo do presente estudo foi isolar C. perfringens a partir das fezes e carcaças de suínos no abatedouro, caracterizar os isolados quanto à presença dos genes codificadores de enterotoxina, toxina alfa, beta, épsilon, iota e beta 2 através da PCR e comparar os isolados através da eletroforese em campo pulsado (PFGE). A frequência de isolamento do agente em carcaças e em intestinos de suínos foi de 58,8% para ambos os tipos de amostras. De acordo com a reação em cadeia pela polimerase, somente a toxina alfa foi detectada, sendo todos os isolados negativos para toxina beta2 e enterotoxina. Através da técnica de PFGE, as cepas foram caracterizadas em 35 pulsotipos, sendo que, em apenas um caso, um isolado de amostras de carcaças foi agrupado no mesmo pulsotipo do isolado de fezes do mesmo animal, indicando que a possibilidade de contaminação cruzada no processamento da carcaça foi baixa. Apesar da alta prevalência de C. perfringens em carcaças de suínos provenientes dos abatedouros avaliados, o risco de intoxicação alimentar para os consumidores de carne suína brasileira é baixo, já que todas as cepas foram negativas para o gene cpe, codificador de enterotoxina.

El presente trabajo ofrece una breve visión de cómo se ha enfrentado el problema del ofidismo en Costa Rica, y en especial, de cómo la investigación científica y tecnológica ha contribuido a tal fin. Se resumen los orígenes de la lucha antiofídica en el país y de la creación del Instituto Clodomiro Picado en la Universidad de Costa Rica, en 1970. Se describen las primeras etapas de su labor, y la evolución de distintas líneas de investigación sobre serpientes, venenos y antivenenos, que por espacio de cuatro décadas han contribuido a que en el país y en la región centroamericana, existan recursos terapéuticos adecuados y suficientes para enfrentar el ofidismo.The present work offers a brief overview on how the problem of ophidism has been confronted in Costa Rica, and especially, on how scientific and technological research has contributed to this goal. The origins of the antiophidic struggle in the country and the creation of the Instituto Clodomiro Picado, at the University of Costa Rica in 1970, are briefly summarized. The first stages of its work are described, as well as the evolution of different research areas on snakes, venoms and antivenoms; which have contributed during four decades to the existence of adequate and sufficient therapeutic resources to tackle ophidism in Costa Rica and in the Central American region.

The toxic action of aqueous wheat (Triticum aestivum) straw extracts was investigated on germination, early seedling growth, some biochemical attributes and the antioxidant enzymes of horse purslane (Trianthemaportulacastrum). Aqueous extracts of wheat straw were prepared by soaking the wheat straw in distilled water in 1:10 w/v ratio and diluted to obtain the concentrations of 0, 25, 50, 75 and 100%. These were used as pre and post emergence in laboratory and screen house trials. Wheat aqueous extracts exhibited phytotoxicity to horse purslane by inhibiting and delaying its germination and suppressing seedling growth. Wheat phytotoxins in its aqueous extracts suppressed the chlorophyll content and soluble protein, and enhanced soluble phenolics and the activity of antioxidant enzymes as catalase, peroxidase and superoxide dismutase in the seedlings of horse purslane compared with the control. Such inhibitory activity is believed to originate from exposure to wheat phytotoxins that are present in its aqueous straw extract. The suppressive effects of wheat straw need to be investigated further under field conditions.A ação tóxica de extratos aquosos da palha de trigo (Triticum aestivum) foi investigada na germinação, no crescimento inicial da plántula, em alguns atributos bioquímicos e nas enzimas antioxidantes de beldroegas-cavalo (Thianthema portulacastrum). Extratos aquosos de palha de trigo foram preparados pela imersão deste em água destilada na proporção de 01:10 m/v e diluidos para obtenção de cinco concentrações (0, 25, 50, 75 e 100%). Estes foram usados como pré e pós-emergência em ensaios de laboratório e casa de vegetação. Os extratos aquosos de trigo exibiram toxicidade às beldroegas-cavalo, inibindo e retardando a sua germinação e suprimindo o crescimento das plántulas. Toxinas no extrato aquoso de trigo suprimiram o teor de clorofila e proteína solúvel, aumentaram os fenóis solúveis e a atividade de enzimas antioxidantes como catalase, peroxidase e superóxido dismutase em plántulas de beldroega-cavalo comparado ao controle. Acreditase que essa atividade inibitória origina-se da exposição das beldroegas-cavalo às toxinas presentes no extrato aquoso de palha de trigo. Efeitos supressivos da palha de trigo precisam ser investigados em condições de campo.

Mushrooms have been used as components of human diet and many ancient documents written in oriental countries have already described the medicinal properties of fungal species. Some mushrooms are known because of their nutritional and therapeutical properties and all over the world some species are known because of their toxicity that causes fatal accidents every year mainly due to misidentification. Many different substances belonging to poisonous mushrooms were already identified and are related with different symptoms and signs. Carcinogenicity, alterations in respiratory and cardiac rates, renal failure, rhabidomyolisis and other effects were observed in toxicity studies with various species including edible and therapeutic ones. Proper identification is important to avoid accidents and toxicity studies are necessary to assure the safe use of mushrooms as food and for medicinal purposes.Las setas se han utilizado como componentes de la dieta humana y muchos documentos antiguos escritos en los países orientales se han descrito ya las propiedades medicinales de las especies de hongos. Algunos hongos son conocidos por sus propiedades nutricionales y terapéuticas y de todo el mundo, algunas especies son conocidas debido a su toxicidad que causa accidentes mortales cada año, principalmente debido a errores de identificación. Muchas sustancias diferentes que pertenecen a las setas venenosas estaban ya clasificadas y están relacionados con diferentes síntomas y signos. Carcinogenicidad, alteraciones de la frecuencia respiratoria y cardiaca, insuficiencia renal, rhabidomyolisis y otros efectos se observaron en estudios de toxicidad con varias especies incluidas las alimenticias y terapéuticas. La correcta identificación es importante para evitar accidentes y los estudios de toxicidad son necesarias para asegurar el uso seguro de las setas como alimento y con fines medicinales.

Virulence factors and antimicrobial resistance patterns of Escherichia coli isolates were evaluated. A total of 80 E. coli isolates were evaluated, being 64 from clinical samples (intestinal content and fragments of organs from diarrheic piglets), seven from feces of clinically healthy piglets and sows, and nine environmental samples (five from facilities, two from feed, one from insect, and one from waste). Molecular characterization was performed by PCR detection of fimbriae and toxin genes and plasmid content determination. The isolates were also characterized according to their resistance or sensitivity to the following drugs: ampicillin, trimethoprim:sulfamethoxazole, tetracycline, amikacine, colistin, norfloxacin, florfenicol, enrofloxacin, cefalexin, trimethoprim, neomycin, chloramphenicol, and gentamicin. From 80 E. coli isolates, 53.8% were classified as enterotoxigenic E. coli (ETEC), 2.5% were shiga toxin-producing E. coli (STEC), and 43.8% showed a non specific pattern and were unclassified. One fecal isolate from non-diarrheic piglet was classified as ETEC by PCR. Clinical isolates showed resistance mainly for tetracycline and trimethoprim:sulfamethoxazole. Plasmidial DNA was observed in 70 isolates, being 78.5% of clinical isolates, 8.57% of non-diarrheic feces, and 12.8% of environment.Os fatores de virulência e a resistência aos antimicrobianos foram avaliados em Escherichia coli. Um total de 80 isolados de E. coli, sendo 64 de amostras clínicas (conteúdo intestinal e fragmentos de órgãos de leitões diarreicos), sete das fezes de porcas e leitões saudáveis e nove de amostras ambientais (cinco de instalações, dois de alimentos, um de inseto e um de esterqueira). A caracterização molecular feita pela PCR objetivou detectar fimbrias e toxinas, bem como a determinação do conteúdo de plasmídeos. Os isolados foram caracterizados quanto à resistência ou sensibilidade às seguintes drogas: ampicilina, sulfazotrim, tetraciclina, amikacina, colistina, norfloxacina, florfenicol, enrofloxacina, cefalexina, trimetoprim, neomicina, cloranfenicol e gentamicina. Dos 80 isolados, 53,8% foram classificados como E. coli enterotoxigênica (ETEC), 2,5% como E. coli produtora de shiga toxina (STEC) e 43,8%, por não apresentarem padrão específico, não foram classificadas. Pela PCR, um isolado de fezes de suíno sem diarreia foi classificado como ETEC. Os isolados das amostras clínicas foram principalmente resistentes à tetraciclina e à sulfazotrim. Em 70 isolados, observaram-se DNA plasmidial, destes 78,5% foram obtidos de amostras clínicas, 8,57% de leitões sadios e 12,8% de amostras ambientais.

Clostridium perfringens es un bacilo grampositivo anaerobio con capacidad de formar esporas. Es uno de los patógenos bacterianos con mayor distribución en el medio ambiente, ya que puede ser aislado de muestras de suelo y de agua y además forma parte de la microbiota intestinal de animales y humanos. Sin embargo, en ciertas ocasiones puede actuar como patógeno oportunista y causar enfermedades como la gangrena gaseosa, la enterotoxemia del ovino y del caprino y la disentería del cordero, entre otras. En humanos, está asociado a enfermedades como la intoxicación por alimentos, la enterocolitis necrotizante en niños y la enteritis necrótica o pigbel de las tribus de Papúa-Nueva Guinea. El renovado interés que existe actualmente en el estudio de C. perfringens como patógeno veterinario y humano, junto con el avance de la biología molecular, han hecho posible que la ciencia tenga hoy un conocimiento más profundo sobre la biología y la patogenia de esta bacteria. En esta revisión bibliográfica se discuten y actualizan los principales aspectos de la patogenia intestinal de C. perfringens teniendo en cuenta las toxinas con mayor importancia médica descritas hasta el presente.Clostridium perfringens is an anaerobic gram-positive spore-forming bacillus. It is one of the pathogens with larger distribution in the environment; it can be isolated from soil and water samples, which also belongs to the intestinal flora of animals and humans. However, on some occasions it can act as an opportunistic pathogen, causing diseases such as gas gangrene, enterotoxemia in sheep and goats and lamb dysentery, among others. In human beings, it is associated to diseases such as food poisoning, necrotic enterocolitis of the infant and necrotic enteritis or pigbel in Papua-New Guinea tribes. The renewed interest existing nowadays in the study of C. perfringens as a veterinarian and human pathogen, together with the advance of molecular biology, had enabled science to have deeper knowledge of the biology and pathology of these bacteria. In this review, we discuss and update the principal aspects of C. perfringens intestinal pathology, in terms of the toxins with major medical relevance at present.

Bacillus cereus es un bacilo Gram-positivo de amplia distribución en la naturaleza y asociado a diversos tipos de alimentos que, bajo ciertas circunstancias causa patologías de diversa índole. Se han descrito cepas diarrogénicas y eméticas basándose en el tipo de toxinas producidas. Con el fin de determinar el riesgo de salud que representa en esta bacteria, se determinó el potencial toxigénico de cepas aisladas a partir de quesos maduros con especias, quesos crema con especias y leches deshidratadas expendidas en San José, Costa Rica, mediante un PCR múltiple con oligonucleótidos específicos para los genes codificantes de las toxinas HBL y Nhe. A partir de 45 muestras recolectadas, se obtuvieron 15 aislamientos de B. cereus, (60% provenientes de queso crema con especias, 7% de leche deshidratada y 13% de queso maduro con especias). Todas las cepas estudiadas presentaron al menos uno de los genes analizados, seis de ellas provenientes de leches deshidratadas y quesos crema, exhibieron evidencia molecular de los genes nheB, nheA, nheC, hblD, hblA y hblC lo cual permite confirmar la correlación descrita para la presencia de los operones codificantes para la HBL y la Nhe. No obstante, la no detección de un gen no puede considerarse como prueba definitiva de su ausencia dado que existen polimorfismos en las secuencias de los genes aquí analizados. Los resultados demuestran que múltiples cepas de B. cereus encontradas en lácteos comprados en Costa Rica contienen los genes necesarios para sintetizar toxinas, por lo tanto es importante el manejo adecuado de estos productos ya que eventualmente pueden representar un riesgo para la salud pública.Bacillus cereus is a Gram positive rod widely distributed in nature and associated to different types of food that, under some circumstances, may cause pathology to human beings. Diarrheic and emetic strains have been described based on the type of toxins produced. In order to determine the risk to health represented by this bacteria, the toxigenic potential of strains isolated from cheese with spices, spread cheese with spices and dehydrated milk, all sold in San José, Costa Rica, were determined using a multiplex PCR technique with oligonucleotides specific for the genes coding toxins HBL and Nhe. From 45 samples collected, 15 isolates of B cereus were obtained (60% coming from spread cheese with spices 7% from dehydrated milk and 13% from cheese with spices). All the strains analyzed presented at least one of the genes analyzed; six of them, coming from dehydrated milk and spread cheese, showed molecular evidence of the genes nheB, nheA, nheC, hblD, hblA y hblC, confirming the correlation described for the presence of operons codifying for HBL and Nhe. Nevertheless, the no detection of a gene cannot be considered as a definitive proof of its absence, given the existence of polymorphism in the sequences of the genes analyzed. The results obtained show that multiple of the B cereus strains found in lactic products from Costa Rica have the necessary genes for synthesizing toxins, so the correct handling of these products is very important since they can represent a risk for public health.

As plantas daninhas se constituem no principal problema a impor limitação à exploração da agropecuária nas áreas tropicais. Entretanto, o controle químico dessas plantas tem gerado insatisfações de ordem social, quer porque contaminam as fontes de recursos naturais ou por comprometerem a qualidade dos alimentos da dieta dos animais, em geral, e dos humanos, em particular. Os objetivos deste trabalho foram identificar e caracterizar a atividade alelopática do filtrado de cultura produzido pelo fungo Fusarium solani f. sp. pipers. Foram avaliados os efeitos das toxinas, nas concentrações de 1,0 e 4,0%, sobre a germinação de sementes e o desenvolvimento da radícula e do hipocótilo das plantas daninhas malícia (Mimosa pudica) e mata-pasto (Senna obtusifolia). Os resultados mostraram presença de atividade alelopática inibitória, com variações de acordo com a concentração e a planta receptora. A intensidade dos efeitos inibitórios induzidos pelo extrato esteve positivamente associada à concentração, com efeitos mais intensos verificados a 4,0%. Independentemente da concentração e do bioensaio, a espécie malícia se mostrou mais sensível aos efeitos do filtrado da cultura. O desenvolvimento da radícula foi o fator da planta mais intensamente inibido. Os resultados indicam a existência de potencial de utilização da toxina produzida pelo fungo, como fonte alternativa no controle de plantas daninhas, o que justifica estudos mais avançados.Weeds are a major problem limiting agriculture and cattle raising activities in the tropics. Current chemical control measures have raised environmental concerns due to their potential of contaminating natural resources and compromising the quality of animal feed. The objective of this paper was to identify and characterize the potential allelopathic activity of Fusarium solani f. sp. pipers culture filtrate. The effects of the toxin were analyzed at 1% and 4% concentration, on seed germination and radicle and hypocotyl elongation of the weeds Mimosa pudica and Senna obtusifolia. The results showed potential inhibitory allelopathic activity of the Fusarium culture filtrate, varying according to concentration and receiving plants. The intensity of the inhibition effects promoted by the extracts was clearly associated to concentration, with the major effect being observed at 4%. Regardless of concentration and bioassays, Mimosa pudica was more sensitive to the toxin effects of the culture filtrate. Radicle elongation was more intensely inhibited by the culture filtrate toxins. The results showed potential for the use of the toxins produced by Fusarium solani f. sp. pipers, as an alternative source to control weeds. However, further studies should be carried out.

El objetivo de este estudio fue comparar el recuento de Fusarium verticillioides y la acumulación de fumonisinas en mazorcas cubiertas y no cubiertas, bajo diferentes condiciones de humedad y temperatura. Se colocaron bolsas de papel permeable a la humedad sobre las inflorescencias femeninas. La cobertura de las inflorescencias femeninas no impidió la infección de los granos de maíz. Por otro lado, se detectaron diferencias significativas en el contenido de fumonisinas B1 y B2 entre granos de mazorcas cubiertas con respecto a los granos provenientes de mazorcas sin cubrir. Las condiciones de elevada humedad y temperatura generadas en las mazorcas cubiertas, favorecieron significativamente los niveles de fumonisinas. La información aportada sobre el nivel de infección del patógeno y la interacción de diferentes condiciones de temperatura y humedad que influyen en la síntesis de fumonisinas, permite seguir evaluando el comportamiento de Fusarium en el cultivo de maíz.

Resumen Objetivo. Utilizar la técnica de amplificación aleatoria de ADN polimórfico ( random amplification of polymorphic DNA, RAPD para caracterizar molecularmente cepas de Staphylococci productoras de toxinas, aisladas de operarios de plantas de producción de alimentos. Materiales y métodos. Se utilizaron 31 aislamientos enterotoxigénicos de Staphylococci para la extracción y cuantificación de ADN. Posteriormente, se realizó un ciclo general de amplificación utilizando los oligonucleótidos HLWL-74 y arbitrario, seguido por la visualización de los productos de RAPD por electroforesis en gel de agarosa. Resultados. Para los dos oligonucleótidos utilizados, se observaron de 1 a 15 bandas, dos linajes, divididos en tres conglomerados (A, B y C). El oligonucleótido arbitrario generó 10 bandas polimórficas (66,66%) y el oligonucleótido HLWL-74 arrojó 13 bandas altamente polimórficas (86,66%). Cada oligonucleótido mostró un agrupamiento diferente de cada una de las cepas, lo cual muestra una alta diversidad de aislamientos de Staphylococci presentes en humanos. Conclusiones. Se presentó una alta diversidad molecular en cuanto a aislamientos de garganta, nariz y manos de un mismo individuo, así como en todos los aislamientos analizados, lo cual demuestra que las cepas enterotoxigénicas de Staphylococci encontradas en los operarios analizados tienen una alta diversidad molecular.Objective. To use Randomly Amplified Polymorphic DNA (RAPD) to compare molecularly enterotoxigenic Staphylococci strains isolated from people working in food processing plants. Materials and methods. 31 Staphylococci enterotoxigenic isolates were used for extraction and quantification of DNA, followed by a general amplification cycle with the HLWL-74 and arbitrary oligonucleotides with visualization of the RAPD products by agarose gel electrophoresis. Results. The two oligonucleotides used generated 1 to 15 bands, two mayor lineages divided in three clusters (A, B, and C). The arbitrary oligonucleotide generated 10 polymorphic bands (66.66%), the HLWL-74 oligonucleotide generated 13 polymorphic bands (86.66%). Each oligonucleotide generated a different type of grouping with respect to each of the strains analyzed. This shows a high diversity between the human isolates of Staphylococci. Conclusion. A high molecular diversity was present amongst throat, nose and hands isolates from the same person, and among the analyzed isolates; this demonstrates a high molecular diversity in Staphylococci enterotoxigenic isolates.

The estuarine complex of Paranaguá - ECP (South Brazil, 25º30'S, 48º30'W) is a large subtropical system, where pristine mangrove forests are still present, and fishery and aquaculture are important economic activities. This work investigated the occurrence of harmful algae in Paranaguá Bay, as well as the presence of toxins in the filter feeding mussel Mytella guyanensis, a local fishery resource. Samples along the Paranaguá sub-system were collected almost monthly from August 2002 to October 2003. Besides physical and chemical variables, cell densities of harmful species and presence of toxins in the mussel by mouse bioassay (DSP, PSP) and HPLC (ASP) were performed. HAB species included Pseudo-nitzschia spp., Dinophysis acuminata,Prorocentrum minimum,Gymnodinium catenatum,Phaeocystis spp., Chattonella spp. and Heterosigma akashiwo.Trichodesmium erythraeum and Coscinodiscus wailesii were also included in this study due to their potential for harmful bloom formation. Toxin results showed the occurrence of DSP (December 2002) in shellfish related to the presence of D. acuminata (max. 4,566 cells.l-1). Additionally, cultivated strains produced paralytic and amnesic toxins in laboratory. Spring (October to December, Southern Hemisphere) and late summer (February to April) were the periods of higher abundance of harmful algae, mainly in euhaline and inner polyhaline sectors of the ECP.O complexo estuarino de Paranaguá (CEP; 25º30'S, 48º30'W), localizado no litoral sul do Brasil, abriga extensas áreas preservadas de manguezais e tem a pesca e aqüicultura como importantes atividades econômicas. Este trabalho investigou a ocorrência de microalgas nocivas no CEP e a presença de ficotoxinas no molusco bivalve Mytella guyanensis. Para tanto, foram coletadas amostras com periodicidade aproximadamente mensal, entre agosto de 2002 e outubro de 2003. Foram avaliadas variáveis físico-químicas, densidade de espécies nocivas e a presença de toxinas nos moluscos através de bioensaio com camundongos (DSP e PSP) e por cromatografia líquida (ASP). As espécies nocivas encontradas foram Pseudo-nitzschia spp., Dinophysis acuminata,Prorocentrum minimum,Gymnodinium catenatum,Phaeocystis spp., Chattonella spp. e Heterosigma akashiwo. Além dessas, Trichodesmium erythraeum e Coscinodiscus wailesii foram também incluídas no estudo pelo potencial de produzirem eventos nocivos na região. Toxinas diarréicas (DSP) foram detectadas em moluscos em dezembro de 2002 associadas à presença de D. acuminata (até 4.566 cel.l-1). Toxinas paralisantes e amnésicas foram produzidas por cepas cultivadas em laboratório. Primavera (de outubro a dezembro no hemisfério Sul) e final do verão (fevereiro a abril) foram os períodos de maior abundância de algas nocivas principalmente nos setores euhalino e polihalino interno do CEP.