Antioxidant compounds from Ebenus pinnata

Activity-guided fractionation of the methanol extract of Ebenus pinnata aerial parts led to the isolation of ombuoside (1), kaempferol 3-O-rutinoside (2), rutin (3), catechin (4), and picein (5), along with beta-sitosterol and beta-sitosterol glucoside. Compounds 1-4 showed significant antioxidant activity in the DPPH, and TEAC, reducing power assays.     

Cryopreservation of YamúBrycon siebenthalae Milt

The yamú Brycon siebenthalae is an endemic fish of the Orinoco river basin, but wild stocks are decreasing because of the disruption of their habitat. We evaluated a protocol for the cryopreservation of yamú sperm to contribute to the preservation of this endangered genetic resource. Milt was mixed with a cryoprotectant medium (5.5% glucose, 12% egg yolk, and 5%, 10%, or 15% dimethyl sulfoxide - DMSO) in a ratio 1:4 (milt:medium), stored in 0.5-mL French straws, frozen in nitrogen liquid vapor (-76 C), then immersed and stored in liquid nitrogen for 10 d or 12 mo. Motility of thawed spermatozoa was higher ( P < 0.001) in 10% DMSO medium than 5% DMSO or 15% DMSO mediums; but lower than the control ( P < 0.001). With sperm cryopreserved, the highest level of fertilization was achieved with 10% DMSO ( P < 0.001) after 10 d or 12 mo of cryopreservation. Fertilization of eggs inseminated with 6.4 × 10⁹ spermatozoa per g of eggs was higher ( P <0.05) than with 1.6 × 10⁹ spermatozoa per g of eggs. There was no difference (P > 0.05) in fertilization between insemination doses of 3.2 × 10⁹ and 6.4 × 10⁹ spermatozoa per g of eggs. Cryopreservation of yamu milt can be performed successfully with a simple medium combined with 10% of DMSO as cryoprotectant. The highest level of fertility was achieved using between 3 × 10⁹ and 6 × 10⁹ spermatozoa per g of fresh eggs.     

Genetic diversity of Phaeoisariopsis griseola in Argentina as revealed by pathogenic and molecular markers

Angular leaf spot, a disease of common bean produced by Phaeoisariopsis griseola, an imperfect (Deuteromycotina) fungus, causes significant yield losses in Argentina. The development of a strategy to control and/or reduce the impact of P. griseola requires a previous knowledge of the population structure. Therefore, the purpose of this work was to analyze diversity among 45 isolates of P. griseola collected within the production area of common bean in Northwestern Argentina. Pathotypes diversity was determined based on a set of bean differentials and genomic differences between isolates were determined by means of molecular markers. We confirmed that isolates belonging to Middle American and Andean groups coexist in Northwestern Argentina and the level of diversity between them was considerable and of similar level within each group. Even though the number of isolates analyzed was 45, among them 37 were Middle American and only eight were Andean. The number of haplotypes found based on ISSR and RAPD markers were 18 and as expected, they were unrelated with pathotypes. The wild bean species, Phaseolus vulgaris var. aborigineus, showed a high level of tolerance to most pathotypes of P. griseola except 63.63 and 63.23. This together with the fact that none of the bean differentials was resistant to all pathotypes led us to conclude that the range of pathogenic responses might be conditioned by multigenic interactions between the pathogen and the host. Our results not only provided basic information about the diversity of the causative agent of the disease but it will also help to develop cultivars with enhanced tolerance and/or resistance to the disease.     

PCR–RFLP and Sequence Data Delineate Three Diaporthe Species Associated with Stone and Pome Fruit Trees in South Africa

Diaporthe species include canker pathogens on a wide variety of hosts. In South Africa, Diaporthe canker of apple, pear and plum rootstocks has been attributed to Diaporthe ambigua. Recently, we recognized that isolates of D. ambigua exhibited different morphological features and thus questioned the identity of these isolates. A small set of isolates was thus chosen for comparison using DNA-based methods. Polymerase chain reaction amplification of ribosomal DNA, Restriction Fragment Length Polymorphisms and DNA sequencing revealed that isolates which had been regarded as D. ambigua in the past were three distinct species. These are D. ambigua, D. perjuncta and an unknown Phomopsis sp. This discovery has special relevance to research done on a dsRNA virus previously thought to occur in D. ambigua and now shown to infect D. perjuncta.     

Current Status and Bottle Neck of Octopod Aquaculture: The Case of American Species

The increasing market demand for cephalopods and the experiences obtained with different species has boosted the interest in developing their culture in Latin America. In 2008, an international workshop was held in Puerto Montt, Chile, with 14 experts in experimental cephalopods aquaculture from Brazil, Chile, Spain, and Mexico. Several topics were approached within the holobenthic species Octopus maya and the merobenthic species Enteroctopus megalocyathus, Octopus vulgaris, and Robsonella fontaniana. Part of the conclusions demonstrated that the two greatest difficulties for their production were survival of paralarvae for merobenthic species, and survival of early juveniles for holobenthic species. Besides, there is a need to study the endogenous and exogenous factors affecting health and nutritional status of embryos, paralarvae, and juveniles. These stages, which may limit the culture, should be extensively studied in order to develop the appropriate environmental conditions and culture systems for the physiological and behavioral requirements, from egg incubation up to juveniles to reach a grow‐out phase.     

Riparian coverage affects diets of characids in neotropical streams

Abstract – Aquatic ecosystems are influenced by the surrounding terrestrial environment. This work studied the influence of vegetation of riparian zones on the feeding patterns of two nektonic characids, Astyanax paranae and Bryconamericus iheringii, in a basin surrounded by an agricultural area. Nine streams within the Corumbataí River basin (São Paulo State, Brazil) with varying proportions of adjacent riparian forest (RF) and pastures were set apart in three arbitrary categories: Riparian Forest (>90% RF), Mixed Coverage (banks covered by 30–60% RF; MC) and Pasture (<29% RF, PA); resident characids were sampled in the dry and rainy seasons and evaluated in regard to composition of diets. Astyanax paranae fed on allochthonous food sources in RF and MC, and on autochthonous food sources on PA streams; B. iheringii fed on autochthonous food sources in RF streams and in mixed resources (detritus and sediment) in PA streams. Selection of food source was related to, and altered by, stream channel structure and composition of substratum. Preservation and restoration of native riparian vegetation is key to preservation of resident characids in small streams of this river basin.     

Influence of Habitat and Land Use on the Assemblages of Ephemeroptera,Plecoptera, and Trichoptera in Neotropical Streams

Insects of the orders Ephemeroptera, Plecoptera, and Trichoptera (EPT) are often used to assess the conditions of aquatic environments, but few studies have examined the differences in these communities between riffles and pools. Our objective was to test whether riffles shelter greater richness and abundance of EPT, as well as to assess the sensitivity of these insects for detecting impacts from different land uses in streams in southeastern Brazil. Samples were collected in the dry season of 2012 with a Surber sampler in riffles and pools of nine streams (forest, pasture, and urban areas). Principal component analysis distinguished the streams according to different land uses as a function of percentage of plant cover and water oxygenation level and showed partial distinction between riffles and pools as a function of current speed and percentage of ultrafine sand. Detrended correspondence analysis indicated the distinction in EPT composition between riffles and pools, except in urban streams. The results of this study confirm the expected differences in the EPT fauna structure between riffles and pools, especially in forest and pasture environments. The individual metrics of riffle and pool assemblages showed significantly different responses to land use. Therefore, we suggest individual sampling of riffles and pools, since the metrics of these assemblages’ insects can differ between these habitats and influence the results of assessments in low-order streams.     

Biochemical responses associated with common bean defence against Sclerotinia sclerotiorum

The aim of this study was to investigate changes in defence compounds of common bean cultivars with different levels of resistance to the fungus Sclerotinia sclerotiorum and determine the relation of the compounds to pathogen tolerance. The lines were inoculated with the pathogen and assessed for enzymatic and non-enzymatic parameters related to plant defence: peroxidases (POX), polyphenol oxidases (PPO), catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX), total soluble phenol and lignin contents. Stem tissue samples were collected from two regions of the plant for biochemical analyses. Stem tissue samples were collected from two regions of the plant for biochemical analyses. In the position one, 5 cm of the stem was collected from the region with necrosis caused by the pathogen, and in the position two, 5 cm of the stem was collected from the end of the position one at the times of 12, 24, 48, 72, 96 and 120 h after inoculation (HAI). Greater lignin and total soluble phenol contents and greater induction of POX and SOD activity in inoculated plants in the region near the inoculation (position one) indicate local activation with later signalling for activation of defence mechanisms in other regions of the plant. The genotype with a greater level of resistance was superior to the susceptible one in regard to lignin production and the activities of POX, APX and SOD defence enzymes. These results suggest that a combination of these defence responses in common bean may contribute to greater plant resistance to the pathogen and that these enzymes have potential use in selection of common bean genotypes.