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Clostridium have more than 60 species, they can cause diverse infections in humans and animals by the production of innumerable exotoxins. For example, C.tetani and C botulinum, cause specific diseases (Tetanus and Botulism) because they produce isolated but very potent toxins. Clostridial infections continue to be a very serious public health problem throughout the world. These range from poisonings (such as food-borne or tetanus) to necrotising enterocolitis / bacteremia colitis, myonecrosis and toxic shock syndrome., Clostridium tiene más de 60 especies, pueden causar diversas infecciones en humanos y animales por la producción de innumerables exotoxinas. Por ejemplo, C.tetani y C botulinum, causan enfermedades específicas (tétanos y botulismo) porque producen toxinas aisladas pero muy potentes. Las infecciones clostridiales continúan siendo un problema de salud pública muy serio en todo el mundo. Estos van desde envenenamientos (como los transmitidos por los alimentos o el tétanos) a la enterocolitis necrosante / colitis por bacteriemia, la mionecrosis y el síndrome de shock tóxico.

Cílem této práce bylo zaměřit se na plísně, které jsou častou příčinnou kažení potravin. Z obecného hlediska je popsán pozitivní a negativní význam jejich činnosti. Jednotlivé rody plísní jsou charakterizovány z hlediska výskytu a toxinogenity. Dále je v práci uveden přehled potravin, které jsou nejvíce ohroženy těmito plísněmi., The aim of this study was to focus on fungi, which are often the cause food spoilage. In general terms is describes positive and negative significance of their activities. The various genera of fungi are characterized in terms of occurrence and toxigenity. Further, the study includes a list of foods that are most threatened by these fungi., Katedra analytické chemie, Studentka přednesla obhajobu své bakalářské práce a zodpověděla dotazy zkušební komise.

Este trabajo tuvo como objetivo estudiar las diatomeas presentes en las aguas costeras del área norte del Golfo San Matías (Provincia de Río Negro, Argentina) que han sido citadas como productoras de eventos nocivos en otras áreas geográficas. El material fue recolectado en dos estaciones de muestreo: Las Grutas y Piedras Coloradas, relacionadas con bancos naturales y cultivo de bivalvos respectivamente. Dos taxa potencialmente toxígenos y 18 taxa nocivos no toxígenos fueron hallados. A pesar de que algunos de ellos fueron ocasionalmente abundantes en el plancton del área, ninguno produjo discoloraciones evidentes ni se detectó que hubieran causado efectos nocivos durante el período de estudio., Diatoms responsible for harmful events in other geographic areas, found in the coastal waters of the San Matías Gulf (Río Negro Province, Argentina), were studied. Materials were collected in two sampling stations related to natural banks and cultures of bivalves: Las Grutas and Piedras Coloradas. Two potentially toxigenic taxa and 18 harmful non toxigenic taxa were found. Despite that some of these taxa were occasionally abundant in the plankton of the area, none of them caused evident discolorations or detectable harmful effects during the study period.

The dinoflagellate species originally described as Pfiesteria shumwayae Glasgow et Burkholder, recently transferred to a new genus, Pseudopfiesteria Litaker et al., is reclassified into the redefined genus Pfiesteria Steidinger et Burkholder, as Pfiesteria shumwayae within the order Peridiniales. This change is based upon consideration of a compilation of previous and new morphological analyses and molecular phylogenetic analyses. Morphological analysis with scanning and transmission electron microscopy supports previous findings except in the sulcal area. In the cells examined, the sulcus is partly concealed by the peduncle cover plate (p.c.), which originates at the right side of the sulcus along the left side of the 6c and 5‴ plates. The fine structure of the p.c. appears similar to that of other thecal plates. The 1″ plate can also extend slightly over the sulcus. Transmission electron microscopy revealed that Pfiesteria shumwayae can have at least six sulcal plates; the number remains uncertain and may vary. The sulcal plates of this small, delicately thecate species have not been clearly discerned by scanning electron microscopy of membrane-stripped and/or suture-swollen cells. The Kofoidian thecal plate formula for the genus Pfiesteria is Po, cp, X, 4′, la, 5-6″, 6c, p.c., ?s, 5‴, 0p, 2‴′. The monophyletic grouping of "pfiesteria-like" taxa within the order Peridiniales, as well as the grouping of Pfiesteria piscicida and Pfiesteria shumwayae within the same genus, is also supported by the preponderance of previous molecular evidence, and by the phylogenetic trees contributed in the present analysis. Pfiesteria appears to be closely related to as-yet informally described cryptoperidiniopsoids and calcareous dinoflagellates such as Thoracosphaera; thus, the family classification requires revision that is beyond the scope of this study. © 2006 Elsevier B.V. All rights reserved.

Clostridioides difficile (C. difficile) is the leading cause of hospital acquired diarrhoeal infection. Its pathology is mainly due to two toxins, TcdA and TcdB. The failure to treat recurrent infection can culminate in death and thus preventative measures are of urgent need. Current vaccine trials in humans are exclusively focused on parenteral delivery of toxin-based formulations. While these vaccines elicit toxin-neutralising serum antibody responses, they fail to provide protection against colonisation and therefore Clostridium difficile infection (CDI). Ideally a vaccine targeting C. difficile would aim to generate a local mucosal immune response (i.e., secretory IgA that directly targets the site of infection). In this study, a non-toxigenic strain of C. difficile (NTCD) was utilised as a delivery system, where immunisation with recombinant spores would allow direct delivery of vaccine candidates to the ileum. To provide a mechanism of release from the cell, as well as increase immunogenicity, a fragment of the TcdB receptor binding domain (previously shown to be immunogenic) was fused to the signal peptide of lipoprotein and colonisation factor CD0873 with a view to creating a TcdB antigen which is naturally lipidated. Both this TcdB construct, and full-length CD0873 were utilised as vaccine candidates. Recombinant episomal plasmids were engineered and conjugated into NTCD strain T7, generating strains capable of expressing these vaccine candidates following germination. Western immunoblotting demonstrated the ability of these strains to produce antigens which are secreted into the extracellular milieu. Spores of these recombinant strains were then used to immunise mice and hamsters. Tissues harvested from immunised animals demonstrated a high antigen-specific IgA and IgG titre compared to animals immunised with strains of the wild type T7 strain. They also demonstrated the ability to reduce binding of C. difficile to Caco-2 colorectal cells, and reduce cytot