A survey of aquatic macroinvertebrates in a river from the dry corridor of Nicaragua using biological indices and DNA barcoding.

Aquatic macroinvertebrates are widely used as indicators for water quality assessment around the world. Modern strategies for environmental assessment implement molecular analysis to delimitate species of aquatic macroinvertebrates. Delimitation methods have been established to determine boundaries between species units using sequencing data from DNA barcodes and serve as first exploratory tools for taxonomic revisions. This is useful in regions such as the neotropics where aquatic macroinvertebrate habitats are threatened by human interference and DNA databases remain understudied. We asked whether the biodiversity of aquatic macroinvertebrates in a stream in Nicaragua, within the Central American Dry Corridor, could be characterized with biological indices and DNA barcoding. In this study, we combined regional biological indices (BMWP-CR, IBF-SV-2010) along with distance-based (ASAP, BIN) and tree-based (GMYC, bPTP) delimitation methods, as well as nucleotide BLAST in public barcode databases. We collected samples from the upper, middle, and low reaches of the Petaquilla river. The three sites presented excellent water quality with the BMWP-CR index, but evidence of high organic pollution was found in the middle reach with the IBF-SV-2010 index. We report a total of 219 COI sequences successfully generated from 18 families and 8 orders. Operational taxonomic units (OTUs) designation ranged from 69 to 73 using the four methods, with a congruency of 92% for barcode assignation. Nucleotide BLAST identified 14 species (27.4% of barcodes) and 33 genera (39.3% of barcodes) from query sequences in GenBank and BOLD system databases. This small number of identified OTUs may be explained by the paucity of molecular data from the Neotropical region. Our study provides valuable information about the characterization of macroinvertebrate families that are important biological indicators for the assessment of water quality in Nicaragua. The application of molecular approaches will allow the study of local diversity and further improve the application of molecular techniques for biomonitoring.

The Coutinho index as a simple tool for screening patients with advanced forms of Schistosomiasis mansoni: a validation study.

BACKGROUND: Periportal fibrosis (PPF) is the major pathological consequence of Schistosoma mansoni infection. The Coutinho index-the alkaline phosphatase (ALP) to platelet ratio ([ALP/upper limit of normality {ULN}]/platelet count [106/L] x 100)-was validated. Validation consisted of modest laboratory tests to predict advanced PPF. METHODS: A total of 378 individuals from an endemic area of Brazil with a previous history of the disease and/or a positive parasitological examination were evaluated. We used ultrasound examination as the gold standard for classification of the PPF pattern and measured the biological markers of the index. RESULTS: Forty-one individuals (10.8%) without PPF, 291 (77%) with moderate PPF and 46 (12.2%) with advanced PPF, were identified. ALP and platelet count were used for the index. The cut-off point ≥0.228 predicted the presence of fibrosis with an area under the receiver operating characteristic curve (AUROC) of 0.56, sensitivity of 68.6% and specificity of 46.3%. There was an absence of PPF in 46.3% of individuals without fibrosis and the presence of PPF in 68.5% of cases with moderate and advanced ultrasound fibrosis. The identification of advanced fibrosis with a cut-off point ≥0.316 revealed an AUROC curve of 0.70, sensitivity of 67.4% and specificity of 68.3%, thus confirming the advanced phase in 65.2% of cases compared with ultrasound. CONCLUSION: The Coutinho index was able to predict advanced PPF in most individuals. It is valid as a new tool, uses routine laboratory tests and therefore is more accessible for screening patients with a severe form of the disease in endemic areas.

Compatibility of Beauveria bassiana and alternative phytosanitary products.

AIMS: To assess the compatibility of alternative phytosanitary products (APPs) with the entomopathogenic fungus Beauveria bassiana (Bals.) Vuillemin. METHODS AND RESULTS: The APPs used were Baicao, Orobor® , Topneem, Rotenat and Compostonat at concentrations recommended by the manufacturers (CR), and then half (1/2CR) and double (2CR). To evaluate the compatibility, the following parameters were analysed: germination, colony forming units (CFUs), vegetative growth and conidia production. Compatibility was assessed using rates of toxicity and biological index. The association of APPs and B. bassiana was also evaluated for pathogenicity against larvae of third instar Anagasta kuehniella Zeller (Lepidoptera: Pyralidae) (1·0 × 108 conidia per ml). The germination of conidia of B. bassiana was reduced only by the product Orobor® . The CFUs were not affected by any products. The colony diameter was reduced when in contact with the products Baicao and Orobor® . For conidia production per colony, all products reduced this parameter. None of the products affected the pathogenicity of the fungus on A. kuehniella. CONCLUSIONS: All APPs tested are compatible with B. bassiana. SIGNIFICANCE AND IMPACT OF THE STUDY: The natural products tested and used in the field are considered compatible with B. bassiana under laboratory conditions, making possible new studies and the use of these in insect control.