The structure of shallow water fish assemblages in sandy beaches of a tropical bay in the southwestern Atlantic

Ichthyological Research - The spatial and seasonal dynamics of shallow water fish assemblages and their relationship with physical-chemical variables were investigated on Guanabara Bay, one of the...     

Insecticidal action of Annona coriacea lectin against the flour moth Anagasta kuehniella and the rice moth Corcyra cephalonica (Lepidoptera: Pyralidae)

Annona coriacea lectin (ACLEC) was tested for insecticidal activity against larvae of two pyralid moths, Anagasta kuehniella and Corcyra cephalonica. ACLEC produced approximately 50% mortality and mass loss in A. kuehniella larvae when incorporated into an artificial diet at levels of 1.5% and 1.0% (w/w), respectively. In contrast, the inclusion of up to 2% ACLEC in the diet did not significantly decrease the survival or weight of C. cephalonica larvae. The nutritional indices for A. kuehniella and C. cephalonica suggested that ACLEC had a multi-mechanistic mode of action and was an antifeedant for both insects. The toxicity in A. kuehniella apparently resulted from a change in the gut membrane environment and consequent disruption of digestive enzyme recycling mechanisms. Affinity chromatography showed that ACLEC bound to midgut proteins of A. kuehniella and C. cephalonica. However, the 14 kDa subunit of ACLEC was not digested by midgut proteases of A. kuehniella, but was degraded by the corresponding C. cephalonica proteases within a few hours. These findings suggest the possibility of using ACLEC to engineer crop plants.     

Direct molecular profiling of minicircle signatures and lineages of Trypanosoma cruzi bloodstream populations causing congenital Chagas disease

Congenital transmission of Trypanosoma cruzi may occur in some or all the gestations from a T. cruzi-infected mother. Variable rates of congenital transmission have been reported in different geographical areas where different parasitic strains predominate, suggesting that parasitic genotypes might play a role in the risk of congenital transmission. Moreover, in cases of transmission it is unknown if the whole maternal T. cruzi population or certain clones are preferentially transmitted by the transplacental route. In this study, bloodstream T. cruzi lineages were identified in blood samples from congenitally infected children, transmitting and non-transmitting mothers and unrelated Chagas disease patients, using improved PCR strategies targeted to nuclear genomic markers. T. cruzi IId was the prevalent genotype among 36/38 PCR-positive congenitally infected infants, 5/5 mothers who transmitted congenital Chagas disease, 12/13 mothers who delivered non-infected children and 28/34 unrelated Chagas disease patients, all coming from endemic localities of Argentina and Bolivia. These figures indicate no association between a particular genotype and vertical transmission. Furthermore, minicircle signatures from the maternal and infants' bloodstream trypanosomes were profiled by restriction fragment length polymorphism of the 330-bp PCR-amplified variable regions in seven cases of mothers and congenitally infected infants. Minicircle signatures were nearly identical between each mother and her infant/s and unique to each mother-infant/s case, a feature that was also observed in twin deliveries. Moreover, allelic size polymorphism analysis of microsatellite loci from populations transmitted to twins showed that all clones from the maternal polyclonal population were equally infective to both siblings.     

Tannase production by Paecilomyces variotii

Surface response methodology was applied to the optimization of the laboratory scale production of tannase using a lineage of Paecilomyces variotii. A preliminary study was conducted to evaluate the effects of variables, including temperature ( degrees C), residue (%) (coffee husk:wheat bran), tannic acid (%) and salt solutions (%) on the production of tannase during 3, 5 and 7 days of fermentation. Among these variables, temperature, residues and tannic acid had significant effects on tannase production. The variables were optimized using surface response methodology. The best conditions for tannase production were: temperature (29-34 degrees C); tannic acid (8.5-14%); % residue (coffee husk:wheat bran 50:50) and incubation time of 5 days. The supplementation of external nitrogen and carbon sources at 0.4%, 0.8% and 1.2% concentration on tannase production were studied in the optimized medium. Three different nitrogen sources included yeast extract, ammonia nitrate and sodium nitrate along with carbon source (starch) were studied. Only ammonia nitrate showed a significant effect on tannase production. After the optimization process, the tannase activity increased 8.6-fold.     

Biology and phenology of three leaf beetle species (Chrysomelidae) in a montane forest in southeast Brazil

The population phenology of the cassidines, Coptocycla arcuata and Omaspides trichroa, and the chrysomeline, Platyphora axillaris, was studied at Serra dos Órgãos National Park, State of Rio de Janeiro, southeast Brazil. Monthly surveys of larvae and adults were conducted between 2008 and 2011 at approximately 1000 m altitude on their respective host plants, Cordia polycephala (Boraginaceae), Ipomoea philomega (Convolvulaceae) and Solanum scuticum (Solanaceae). This is the first observation of larviparity and host record for Platyphora axillaris. Although having different life history traits, all species showed similar phenologies. They were abundant from October to March, months of high temperatures and intense rainfall, with two distinct reproductive peaks in the same season. Abundance dropped abruptly during the coldest and driest months, from May to August. Frequently none of these species were recorded during June and July. This phenological pattern is similar to other Chrysomelidae living in subtropical areas of Brazil. Temperature and rainfall appear to be the major factors influencing the fluctuation of these three species.     

How Effective Is Help on the Doorstep? A Longitudinal Evaluation of Community-Based Organisation Support

Community-based responses have a lengthy history. The ravages of HIV on family functioning has included a widespread community response. Although much funding has been invested in front line community-based organisations (CBO), there was no equal investment in evaluations. This study was set up to compare children aged 9–13 years old, randomly sampled from two South African provinces, who had not received CBO support over time (YC) with a group of similarly aged children who were CBO attenders (CCC). YC baseline refusal rate was 2.5% and retention rate was 97%. CCC baseline refusal rate was 0.7% and retention rate was 86.5%. 1848 children were included—446 CBO attenders compared to 1402 9–13 year olds drawn from a random sample of high-HIV prevalence areas. Data were gathered at baseline and 12–15 months follow-up. Standardised measures recorded demographics, violence and abuse, mental health, social and educational factors. Multivariate regression analyses revealed that children attending CBOs had lower odds of experiencing weekly domestic conflict between adults in their home (OR 0.17; 95% CI 0.09, 0.32), domestic violence (OR 0.22; 95% CI 0.08, 0.62), or abuse (OR 0.11; 95% CI 0.05, 0.25) at follow-up compared to participants without CBO contact. CBO attenders had lower odds of suicidal ideation (OR 0.41; 95% CI 0.18, 0.91), fewer depressive symptoms (B = -0.40; 95% CI -0.62, -0.17), less perceived stigma (B = -0.37; 95% CI -0.57, -0.18), fewer peer problems (B = -1.08; 95% CI -1.29, -0.86) and fewer conduct problems (B = -0.77; 95% CI -0.95, -0.60) at follow-up. In addition, CBO contact was associated with more prosocial behaviours at follow-up (B = 1.40; 95% CI 1.13, 1.67). No associations were observed between CBO contact and parental praise or post-traumatic symptoms. These results suggest that CBO exposure is associated with behavioural and mental health benefits for children over time. More severe psychopathology was not affected by attendance and may need more specialised input.     

Purification of a lectin from the marine red alga Gracilaria ornata and its effect on the development of the cowpea weevil Callosobruchus maculatus (Coleoptera: Bruchidae)

A lectin from the marine red alga Gracilaria ornata (Gracilariaceae, Rodophyta) was purified and characterized. The purification procedure consisted of extracting soluble proteins in 0.025 M Tris-HCl buffer, pH 7.5, followed by ammonium sulfate precipitation (70% saturation), ion exchange chromatography on DEAE-cellulose and affinity chromatography on mucin-Sepharose 4B. The purified G. ornata lectin (GOL) showed a single protein band with an apparent molecular mass of 17 kDa when submitted to SDS-polyacrylamide gel electrophoresis under reducing conditions. The native molecular mass of GOL determined by gel filtration on a Sephadex G-100 column was 17.4 kDa and its carbohydrate content was estimated to be 2.9%. Therefore, GOL is a monomeric glycoprotein. The purified lectin agglutinated trypsin-treated erythrocytes from rabbit and chicken but not from human. Its activity was not inhibited by any of the mono- and disaccharides tested but by the complex glycoproteins porcine stomach mucin, lactotransferrin, asialofetuin and bovine and porcine thyroglobulins. Isoelectric focusing showed that GOL is an acidic protein with a pI of 5.4 with analysis of its amino acid composition revealing high contents of Asx, Glx, Ser, Glu, Ala and Cys. When incorporated in artificial seeds, GOL significantly affected the development of Callosobruchus maculatus larvae, indicating the possibility of using this lectin in a biotechnological strategy for insect management of stored cowpea seeds.