Dynamics of fish assemblages on a continuous rocky reef and adjacent unconsolidated habitats at Fernando de Noronha Archipelago, tropical western Atlantic

In recent years, many studies investigated how density-dependent factors, such as shortages in microhabitat and food availability influence the structure of reef fish assemblages. Most of what is currently known, however, comes from comparisons of isolated patch reefs and from correlations between fish abundance and one or few microhabitat variables. In addition, most studies were done in the Caribbean and Indo-Pacific regions, whereas the South Atlantic region has been, to date, understudied. The present study evaluated spatial and temporal variations in reef fish abundance and species richness in a continuous rocky reef and adjacent unconsolidated habitats in a Southwestern Atlantic reef, using underwater techniques to assess both fish numbers and microhabitat variables (depth, rugosity, number of crevices and percent cover of live benthic organisms, bare rock, sand, and limestone). Higher species richness was observed at consolidated substratum stations on both sampling periods (May and October), but fish abundance did not show a significant spatial variation. Topographical complexity and percent cover of algae (except coralline algae) were amongst the most important determinants of species richness, and correlations between fish size and refuge crevice size were observed. The non-random patterns of spatial variation in species richness, and to a lesser extent, fish abundance, were related to differences in substratum characteristics and the inherent characteristics of fishes (i.e. habitat preferences) and not to geographical barriers restraining fish movement. This study highlights the importance of concomitantly assessing several microhabitat variables to determine their relative influence in reef fish assemblages.

Em anos recentes, vários estudos investigaram como os fatores dependentes da densidade, por exemplo, a diminuição na disponibilidade de microhabitats e alimento, influenciam a estrutura das assembleias de peixes. A maior parte do que é atualmente conhecida, no entanto, é oriunda de comparações de recifes isolados e de correlações entre abundância de peixes e uma ou poucas variáveis relacionadas ao microhabitat. Ainda, a maior parte dos estudos foi realizada nas regiões do Caribe e do Indo-Pacífico, enquanto a região do Atlântico Sul tem sido, até o momento, subestimada. O presente estudo avaliou as variações espaciais e temporais da abundância de peixes recifais e da riqueza de espécies em um recife rochoso contínuo e em habitats não-consolidados adjacentes em um recife do Atlântico Sudoeste, utilizando técnicas subaquáticas para avaliar tanto os valores dos peixes como as variáveis do microhabitat (profundidade, rugosidade, número de fendas e porcentagem de cobertura de organismos bênticos vivos, rocha nua, areia e cascalho). Uma maior riqueza de espécies foi observada nos pontos de substrato consolidado em ambos os períodos de amostragem (maio e outubro), mas a abundância de peixes não mostrou uma variação espacial significativa. A complexidade topográfica e a porcentagem de cobertura de alga (exceto alga coralinácea) foram as determinantes da riqueza de espécies e correlações entre tamanho dos peixes e tamanho das fendas de refúgio mais importantes observadas. Os padrões não-randômicos de variação espacial na riqueza de espécies e, em menor grau, abundância de peixes, relacionaram-se com diferenças nas características do substrato e as características inerentes dos peixes (i.e. preferências de habitat) e não a barreiras geográficas restringindo o movimento dos peixes. Este estudo destaca a importância de avaliar concomitantemente diversas variáveis de microhabitat para determinar suas influências relativas sobre as assembleias de peixes.

Mycobiota and mycotoxins in fermented feed, wheat grains and corn grains in Southeastern Buenos Aires Province, Argentina

El trigo (como afrechillo) y el maíz (como grano seco o alimento fermentado) son ingredientes empleados como alimento para el ganado bovino y porcino en la zona sur de la provincia de Buenos Aires (Argentina). Determinar la micobiota y las micotoxinas presentes en estos alimentos es de suma importancia para establecer técnicas de control de los mismos, optimizar la producción animal y minimizar su toxicidad. Por ende, en el sudeste de la provincia de Buenos Aires se llevó a cabo un estudio para identificar la micobiota y las principales micotoxinas presentes en dichos tipos de alimento. Las muestras fueron sembradas para realizar el recuento, el aislamiento y la identificación de los principales géneros de hongos presentes, y analizadas para detectar las micotoxinas de mayor importancia toxicológica: desoxinivalenol (DON), zearalenona (ZEA), toxina T-2 y aflatoxinas (AFLA). Penicillium (74%), Aspergillus (32%) y Scopulariopsis (21%) fueron los géneros más frecuentes en alimentos fermentados. En muestras de maíz, los géneros más relevantes fueron Penicillium (70%), Fusarium (47%) y Aspergillus (34%), mientras que Penicillium (42%), Fusarium (27%) y Alternaria (25%) fueron los más aislados en el caso del afrechillo de trigo. DON fue detectado en el 59% de las muestras de maíz, en el 45% de las muestras de trigo y en el 38% de las muestras de alimento fermentado. ZEA fue detectada en un 36% de las muestras de maíz, en un 49% de las muestras de trigo y en un 16% de las muestras de alimento fermentado. Las toxinas T-2 y aflatoxina B1 fueron detectadas en un 4% de las muestras de maíz. El 18% de las muestras de alimentos fermentados mostraron contaminación con T-2. Las muestras de alimentos fermentados y de trigo fueron negativas para AFLA(AU)

Wheat (as bran) and corn (as dry grain or fermented feed) are main ingredients of feedstuffs used in local cattle and pig farms in the South of the Buenos Aires Province (Argentina). Therefore, determining mycobiota and mycotoxins in wheat and corn is of prime importance for developing feed management techniques to optimise animal production and to minimize toxicity. Then, a mycological survey was carried out in the Southeastern part of the Buenos Aires Province, in order to identify the mycobiota and the main mycotoxins present in fermented feed, wheat grain and corn grain samples. Samples were cultured for fungal quantification, isolation and identification, and analysed for deoxynivalenol (DON), zearalenone (ZEA), T-2 toxin and aflatoxins (AFLA). Penicillium (74%), Aspergillus (32%) and Scopulariopsis (21%) were the prevalent genera in fermented feed. Penicillium (70%), Fusarium (47%) and Aspergillus (34%) were the most frequent fungi isolated from corn. Penicillium (42%), Fusarium (27%) and Alternaria (25%) were the most frequently recovered genera from wheat. DON was detected in 59% of the corn samples, in 45% of the wheat samples and in 38% of the silage samples. ZEA was detected in 36% of the corn samples, in 49% of the wheat samples and in 16% of the silage samples. T-2 toxin and aflatoxin B1 were each detected in 4% of the corn samples. Eighteen percent of the fermented feed samples showed T-2 contamination. Fermented feed and wheat samples were negative for AFLA(AU)

Influencia de la microbiota intestinal en la obesidad y las alteraciones del metabolismo / Influence of the intestinal microbiota on obesity and on metabolic disorders

La obesidad es uno de los principales problemas de salud pública debido al rápido aumento de su prevalencia y a su alta comorbilidad con diversas enfermedades, como el síndrome metabólico, la diabetes y las enfermedades cardiovasculares. Los cambios sociales asociados a una elevada ingesta de alimentos con alta carga energética y una baja actividad física han creado un entorno propenso a la obesidad en todo el mundo. En este contexto, la identificación de nuevos factores implicados en la regulación del balance energético es fundamental a fin de desarrollar estrategias de intervención más eficaces. La microbiota intestinal se considera un nuevo factor implicado en la regulación del peso corporal y las enfermedades asociadas a la obesidad, dada su influencia en las funciones metabólicas e inmunológicas del hospedador. La microbiota intestinal y algunos probióticos también regulan las funciones inmunológicas del individuo, protegiéndolo frente a infecciones y procesos de inflamación crónica. En cambio, los desequilibrios en el ecosistema intestinal (disbiosis) y la endotoxemia pueden ser factores inflamatorios responsables del desarrollo de resistencia a la insulina y del aumento del peso corporal. En función de las relaciones establecidas entre la microbiota intestinal, el metabolismo y la inmunidad, el uso de estrategias dietéticas destinadas a modular la composición de la microbiota, basadas en probióticos y prebióticos, podría contribuir al control de los trastornos metabólicos de forma más eficaz (AU)

Obesity is one of the main public health problems due to its fast prevalence increase and co-morbidities with several diseases, as the metabolic syndrome, diabetes and cardiovascular diseases. Social changes associated to high intake of energy-dense food and low physical activities have created an obesogenic environment worldwide. In this context, the identification of new factors involved in the regulation of the energy balance has mainly the aim of developing more efficient intervention strategies. The intestinal microbiota is considered a new factor involved in the body weight regulation and in diseases associated with obesity through its influence in the metabolic and immunologic functions of the host. The intestinal microbiota and some probiotics also regulate the subject's immunological functions, protecting from infections and chronic inflammation processes. Instead, disorders in the intestinal ecosystem (dysbiosis) and endotoxemia might be inflammatory factors responsible for developing insulin resistance and body weight gain. Based on the relations between the intestinal microbiota, the metabolism and immunity, the use of dietary strategies to modulate the microbiota, based on probiotics and prebiotics, is likely to contribute to the control of the metabolic disorders more efficiently (AU)

Mycobiota of the date palm phylloplane: description and interactions

Se ha analizado la micobiota presente en las hojas de la palmera datilera(Phoenix dactylifera, L.) utilizando diferentes técnicas. Tras lavar y cultivar enplacas fragmentos de hoja de palmera se observó una alta esporulación devarios hongos (Penicillium spp. y Cladosporium spp.). Fusarium oxysporum fueparticularmente abundante en hojas infestadas por la cochinilla roja(Phoenicococcus marlatti Cockerell, 1899). Además se detectó un hongoentomopatógeno no descrito: Lecanicillium cf. psalliotae. Los cultivos dualesy las técnicas de sobreposición de membranas mostraron interacciones entrehongos patógenos de la palmera, entomopatógenos y saprótrofos. Lo mássignificativo fue la fuerte inhibición del hongo patógeno de palmerasPenicillium vermoesenii producida por el entomopatógeno Beauveria bassiana.Ni el hongo F. oxysporum, aislado de la cochinilla roja, ni losentomopatógenos B. bassiana o Lecanicillium dimorphum, causaron síntomascuando fueron inoculados en heridas de pecíolos de P. dactylifera(AU)

We have analysed the mycobiota of date palm (Phoenix dactylifera, L.) leavesusing several techniques. Profusely sporulating fungi (Penicillium spp. andCladosporium spp.) developed when plating leaf fragments and leaf washings.Fusarium oxysporum, was particularly abundant in leaves infested with the redscale insect Phoenicococcus marlatti Cockerell, 1899, but an undescribedLecanicillium cf. psalliotae was also found. Dual and overlay cultures showedinteractions between palm pathogens, entomopathogenic and saprotrophicfungi. The most significant was the strong inhibition of the palm pathogenPenicillium vermoesenii caused by the entomopathogen Beauveria bassiana.No symptoms developed when F. oxysporum isolated from scale insects or theentomopathogens B. bassiana or Lecanicillium dimorphum werewound-inoculated on P. dactylifera petioles(AU)