Papers by Arturo Sierra-beltrán
Una proteína de membrana externa de 48 kDa (omp48) de Aeromonas veronii (A. veronii), que tiene a... more Una proteína de membrana externa de 48 kDa (omp48) de Aeromonas veronii (A. veronii), que tiene afinidad por secreciones de la mucosa (tal como mucina, lactoferrina, inmunoglobulinas o colágeno), induce una respuesta inmune estadísticamente significativa al ser administrada intragástricamente a conejos blancos de Nueva Zelanda. Estudios posteriores mostraron una correlación positiva entre las inmunoglobulinas y la respuesta de células productoras de anticuerpo (CPA). La administración intragástrica del antígeno induce una respuesta vigorosa, tanto local como sistémica, principalmente de inmunoglobulinas A y G contra la omp48 de A. veronii. Estas se evidenciaron por la presencia de (i) células productoras de anticuerpos contra omp48 en el tracto gastrointestinal, bazo y sangre, y (ii) elevados niveles de anticuerpos circulantes. La estimulación del sistema inmune de mucosa mediante antígenos bacterianos inmunogénicos, puede ser una importante alternativa para el control y prevención de enfermedades asociadas a Aeromonas.
Journal of Phycology, Jan 28, 2015
The taxonomic assignment of Prorocentrum species is based on morphological characteristics; howev... more The taxonomic assignment of Prorocentrum species is based on morphological characteristics; however, morphological variability has been found for several taxa isolated from different geographical regions. In this study, we evaluated species boundaries of Prorocentrum hoffmannianum and Prorocentrum belizeanum based on morphological and molecular data. A detailed morphological analysis was done, concentrating on the periflagellar architecture. Molecular analyses were performed on partial Small Sub‐Unit (SSU) rDNA, partial Large Sub‐Unit (LSU) rDNA, complete Internal Transcribed Spacer Regions (ITS1‐5.8S‐ITS2), and partial cytochrome b (cob) sequences. We concatenated the SSU‐ITS‐LSU fragments and constructed a phylogenetic tree using Bayesian Inference (BI) and maximum likelihood (ML) methods. Morphological analyses indicated that the main characters, such as cell size and number of depressions per valve, normally used to distinguish P. hoffmannianum from P. belizeanum, overlapped. No clear differences were found in the periflagellar area architecture. Prorocentrum hoffmannianum and P. belizeanum were a highly supported monophyletic clade separated into three subclades, which broadly corresponded to the sample collection regions. Subtle morphological overlaps found in cell shape, size, and ornamentation lead us to conclude that P. hoffmanianum and P. belizeanum might be considered conspecific. The molecular data analyses did not separate P. hoffmannianum and P. belizeanum into two morphospecies, and thus, we considered them to be the P. hoffmannianum species complex because their clades are separated by their geographic origin. These geographic and genetically distinct clades could be referred to as ribotypes: (A) Belize, (B) Florida‐Cuba, (C1) India, and (C2) Australia.
Quality Assurance and Safety of Crops & Foods, 2018
The main phytopathogenic moulds on citrus fruits, besides from causing great post-harvest losses,... more The main phytopathogenic moulds on citrus fruits, besides from causing great post-harvest losses, are capable of producing mycotoxins that are highly toxic for any human or animal that might eat them. The objective of this study was to determine the mycotoxigenic potential of moulds isolated from the phyllosphere of citrus fruits originating from different orchards and packing-houses in different places around Mexico. In this study, 258 moulds were isolated, finding up to 29 different genera, including host-specific citrus moulds as well as opportunist spoilage moulds. Their pathogenic potential was determined using Citrus latifolia T. (Persian lime), finding 17 phytopathogenic strains, including the presence of phytopathogenic species different from the ones most commonly studied, Penicillium italicum or Alternaria alternata, belonging to the Aspergillus genus and with a high degree of pathogenicity. Their mycotoxigenic potential was determined through molecular techniques, finding as a result that A. alternata, Aspergillus niger and Aspergillus carbonarius have the potential to produce mycotoxins by amplifying specific sequences that partake in the biosynthesis of mycotoxins such as Alternaria toxins, fumonisins, aflatoxins and ochratoxin, respectively. When these moulds receive a stimulus under certain environmental conditions, it might trigger production of such secondary and toxic metabolites. Knowledge of the behaviour of these microorganisms will help in developing the necessary strategies for their post-harvest control, thus ensuring the protection of the end consumer against exposure to such mycotoxins. This research also yielded the first register ever made of microbiota in citrus fruits grown in different states of Mexico.
Journal of Medical Microbiology, 2000
The presence of Helicobacter pylori in the gastroduodenal mucosae is associated with chronic acti... more The presence of Helicobacter pylori in the gastroduodenal mucosae is associated with chronic active gastritis, peptic ulcers and gastric cancers such as adenocarcinoma and low-grade gastric B-cell lymphoma. In response to the presence of antibiotic-resistant strains, the use of vaccines to combat this infection has become an attractive alternative. The present study used a murine model of infection by a mouse-adapted H. pylori strain to determine whether infection in BALB=c mice can be successfully eradicated by intragastric vaccination with H. pylori heparan sulphate-binding proteins (HSBP) covalently coupled to the â-subunit of cholera toxin (CTB). It was shown that vaccination confers protection against exposure of BALB=c mice to the pathogen, as revealed by microbiological, histopathological and molecular methods.
Ecological Studies, 2018
The Scientific Committee of the CRP on Fjords and Coastal Embayments proposed a second OSM to hig... more The Scientific Committee of the CRP on Fjords and Coastal Embayments proposed a second OSM to highlight this progress and the importance of a comparative approach to improve our understanding of HABs. This second OSM focused on four themes: (1) Life history of HAB species; (2) Chemical ecological and toxin interactions; (3) Genetic diversity and (4) Transport and
Sea cucumbers possess evisceration mechanisms and regeneration capacity. The function of tentacle... more Sea cucumbers possess evisceration mechanisms and regeneration capacity. The function of tentacles is to collect food particles. From our results, we suggest these organs could also be part of the digestive system. Therefore proteases in the digestive tract and tentacles of Isostichopus fuscus were partially characterized by histological and biochemical methods. Digestive cells and regions, and secretory granules were observed by histological methods in both organs. Proteolytic extracts of the digestive tract and tentacles showed peak activity at pH 6 and 8. The digestive tract extract had peak activity at 40 and 70 °C, whereas the tentacle extract peak activity was at 60 °C. Both extracts showed activity at 0 to 10 °C. The extracts retained 67 to 75 % residual activity when incubated at 60 °C for 1 h. The effect of different ions and specific inhibitors suggested the presence of cysteine- and metallo-proteases in both organs. SDS-PAGE showed 6 proteins of approximately 40, 43, 49, ...
Toxicon, 1998
overview of the marine food poisoning in Mexico. Toxicon 36, 1493±1502, 1998.ÐIn the course of th... more overview of the marine food poisoning in Mexico. Toxicon 36, 1493±1502, 1998.ÐIn the course of the last decade, huge events related to harmful algal blooms (HAB) have severely aected the environment in Mexico, even causing several human casualties. The tally of the toxins known up to date in Mexican waters includes: neurotoxin shell®sh poisoning (NSP), paralytic shell®sh poisoning (PSP), amnesic shell®sh poisoning (ASP), tetrodotoxin (TTX) or puer ®sh poisoning, ciguatera ®sh poisoning (CFP) and diarrhetic shell®sh poisoning (DSP). Actual epidemiological ®gures profoundly modi®ed the trends manifested on previous decades. Notwithstanding that the red tides are a long time known phenomena in Mexican coasts, no regular observation of the marine environment has been set up. Although there are monitoring activities for PSP toxins on the shell®sh culturing facilities that are exploited for export to the U.S.A., these are only eectively applied on speci®c spots of the Mexican coasts, implying that the biggest part of the country coastal zones are not formerly surveyed. The misleads caused by the medical conception that food poisoning events are mainly due to microbial contamination, is among the factors why the marine food poisoning events are a neglected disease. In spite of the fact that no ocial statistics consider HAB related events as a subject of research or further monitoring by the health authorities, sporadic scienti®c documents related to poisoning events were produced in Mexico. An interesting picture is presented for most of the marine toxins mentioned. Trend and prognosis estimates made with such scarce information, provide a minimum measurement of the reality and urge the need for a permanent monitoring program on the Mexican coasts, a place with one of the greatest marine toxin diversity worldwide.
Marine Pollution Bulletin, 2002
Samples of liver, lung, heart, muscle, and blubber tissue from the carcasses of juvenile gray wha... more Samples of liver, lung, heart, muscle, and blubber tissue from the carcasses of juvenile gray whales (Eschrichtius robustus) found stranded on the coast off the Sea of Cortez, M e exico were analyzed for a range of trace metals (Cu, Fe, Zn, Mn, Ni, Pb, and Cd). The highest concentrations of copper, iron, zinc, and manganese were found in liver; nickel and lead in heart, and cadmium in kidney. In all tissues analyzed, iron, zinc and copper were present in the highest concentrations; however, some whales also showed high levels of cadmium in the kidney which could be related to their diet. Elevated concentrations of copper were found only in the liver of one whale. In general, where low levels of iron were found in the liver, they were associated with poor nutrition. Lead, nickel, manganese and zinc levels in liver were within the normal range, indicating that these whales had not been exposed to high levels of these metals.
Se estudiaron extractos enzimaticos del musculo ventral de Isostichopus fuscus. Se observo maxima... more Se estudiaron extractos enzimaticos del musculo ventral de Isostichopus fuscus. Se observo maxima actividad proteolitica a pH 2, 6 y 8, y 50-60°C. La mayor estabilidad enzimatica fue a pH 2-6 (excepto pH 3), y a 0-40°C. Se detecto una actividad residual mayor a 74% despues del calentamiento a 70°C y 80°C por 1 h, confirmandose la presencia de enzimas termo resistentes. Asimismo, los extractos retuvieron 59% de la actividad inicial despues de almacenarse a 4-5°C por 21 dias. Hg2+ aumento la actividad proteolitica 16%, mientras Cu2+ y Mn2+ la inhibieron parcialmente, lo que sugirio la presencia de cistein y metalo proteasas. El extracto enzimatico se inhibio por pepstatina A, β-mercaptoetanol y EDTA, confirmando la predominancia de aspartil, cistein y metalo proteasas. Por SDS-PAGE se identificaron cuatro proteinas (180.6, 114.5, 91.7 y 52.9 kDa) y estudios de zimografia corroboraron la presencia de proteasas. Despues de purificar el extracto por intercambio anionico se detecto una pr...
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RESUMEN Las floraciones algales nocivas (FAN) pueden definirse como eventos naturales en los que ... more RESUMEN Las floraciones algales nocivas (FAN) pueden definirse como eventos naturales en los que las concentraciones de una o varias especies de microalgas alcanzan niveles que causan daño a otros organismos del medio acuático. En las últimas décadas, se ha ...
Toxicon, 2000
Toxicities and tetrodotoxin distribution in tissues of ®ve puer ®sh species commonly found in the... more Toxicities and tetrodotoxin distribution in tissues of ®ve puer ®sh species commonly found in the littoral of Baja California Peninsula, Mexico (Sphoeroides annulatus, S. lobatus, S. lispus, Arothron meleagris and Canthigaster punctatissima) were evaluated by bioassay and HPLC. The toxicities estimated as tetrodotoxin-equivalents of all species were more than 0.42 mg/g in at least one of the tissues tested, and the highest was found in S. lispus liver (130 mg/g).
Journal of Phycology, 2015
The taxonomic assignment of Prorocentrum species is based on morphological characteristics; howev... more The taxonomic assignment of Prorocentrum species is based on morphological characteristics; however, morphological variability has been found for several taxa isolated from different geographical regions. In this study, we evaluated species boundaries of Prorocentrum hoffmannianum and Prorocentrum belizeanum based on morphological and molecular data. A detailed morphological analysis was done, concentrating on the periflagellar architecture. Molecular analyses were performed on partial Small Sub-Unit (SSU) rDNA, partial Large Sub-Unit (LSU) rDNA, complete Internal Transcribed Spacer Regions (ITS1-5.8S-ITS2), and partial cytochrome b (cob) sequences. We concatenated the SSU-ITS-LSU fragments and constructed a phylogenetic tree using Bayesian Inference (BI) and maximum likelihood (ML) methods. Morphological analyses indicated that the main characters, such as cell size and number of depressions per valve, normally used to distinguish P. hoffmannianum from P. belizeanum, overlapped. No clear differences were found in the periflagellar area architecture. Prorocentrum hoffmannianum and P. belizeanum were a highly supported monophyletic clade separated into three subclades, which broadly corresponded to the sample collection regions. Subtle morphological overlaps found in cell shape, size, and ornamentation lead us to conclude that P. hoffmanianum and P. belizeanum might be considered conspecific. The molecular data analyses did not separate P. hoffmannianum and P. belizeanum into two morphospecies, and thus, we considered them to be the P. hoffmannianum species complex because their clades are separated by their geographic origin. These geographic and genetically distinct clades could be referred to as ribotypes: (A) Belize, (B) Florida-Cuba, (C1) India, and (C2) Australia.
Toxin Reviews, 2008
... Then, it was noted that the events were related to massive red tides and that the people livi... more ... Then, it was noted that the events were related to massive red tides and that the people living in the coasts suffered episodes of coughing, skin rash, and ... The picture in the Yucatán peninsula is similar, with records of fish mortalities dating from 1648 (Ramirez-Granados, 1963). ...
Journal of Phycology, 2003
... Dinophyceae; morphology; planktonic dinoflagellates; Prorocentrales; Prorocentrum mexicanum; ... more ... Dinophyceae; morphology; planktonic dinoflagellates; Prorocentrales; Prorocentrum mexicanum; Prorocentrum rhathymum; red tide; SEM; taxonomy. ... Prorocentrum mexicanum is a photosynthetic planktonic species that has golden chloroplasts, a round central pyrenoid, and a ...
Revista de biologia tropical, 2004
From April 26th to May 15th 2001, a large algae bloom was observed off Tumaco Bay on the Pacific ... more From April 26th to May 15th 2001, a large algae bloom was observed off Tumaco Bay on the Pacific coast of Colombia. This was the first harmful algae bloom (HAB) reported in the region, and reached Gorgona Island, about 120 km north. A year later, starting March 2002, an offshore HAB developed from Cabo Corrientes North to Solano Bay. The typical abundance during the blooms reached 7.5 x 10(6) cells l(-1) for the 2001 event and 1.6 x 10(6) cells l(-1) for the 2002 event. During both events, low temperature and high salinity were recorded. Typical measurements in the area are 27-27.5 degrees C and 30-31.5 psu. Values observed during the two events were 24-24.6 degrees C and 33-34 psu; 3 degrees C below normal and more than 2.5 psu above average values. These conditions are indicative of local upwelling processes at the time of the events. On both occasions, cells corresponding to the Alexandrium catenella/fundeyense/tamarense complex represented 99-100% of the biomass. It was difficul...
The evolution of an ichthiotoxic algal bloom caused by the dinoflagellate Cochlodinium catenatum ... more The evolution of an ichthiotoxic algal bloom caused by the dinoflagellate Cochlodinium catenatum was studied from July to December 2000. The abnormal multiplication of this dinoflagellate occurred in the form of a discoloration spreading between a temperature and salinity interval of 25-32 degrees C and 33-35 ups, respectively. The density of C. catenatum reached 10 841 cells ml(-1). The event was observed in large areas of Banderas Bay affecting 13 fish species, whose massive killing was due to suffocation (gill obstruction and excessive mucus production). The human population around the area did not present respiratory affections or skin irritation. The C. catenatum measurements suggest a hologamic and heterothalic reproduction. Their morphological characteristics suggest that C. polykrikoides, C. heterolobatum and C. catenatum are the same species. It is estimated that the species could be a recent introduction in the Mexican Pacific.
Background. The technique for inducing pearl production in mollusks, which relies on the grafting... more Background. The technique for inducing pearl production in mollusks, which relies on the grafting of a round nucleus and a piece of mantle tissue from a donor within the gonad of a recipient, generates high mortality and rejection rates. Goals. To develop methodological basis for in vitro primary cultivation of mantle cells in the pearl oyster Pinctada mazatlanica, with potential application to pearl production. Methods. Five me-thods for enzymatic dissociation, three different culture media, two cell substrates, and four osmolarities of the culture medium were evaluated. In vitro intake of calcium by mantle tissue was also quantified through histochemistry and atomic absorption spectrophotometry. Results. The addition of collagenase I (414 U/mg), at 37°C increased viability and performance of disaggregated cells, which grew better in RPMI-1640 cell medium with poly-D-lysine. Under these conditions, the cells changed from the round-type cell to the fibroblast-type cell by day th...
Hidrobiológica
Eficiencia de lectinas como inmunoindicadores en juveniles de camarón blanco, Litopenaeus vanname... more Eficiencia de lectinas como inmunoindicadores en juveniles de camarón blanco, Litopenaeus vannamei (Malacostraca: Penaeidae) Efficiency of lectins as immune indicators in juvenile white shrimp, Litopenaeus vannamei (Malacostraca: Penaeidae
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Papers by Arturo Sierra-beltrán