Phenotypic diversity of starch granules in cassava germplasm.

Demand for the development of cassava varieties with different native starches has guided the search for these characteristics in the germplasm of Manihot esculenta Crantz. Therefore, the objective of this study was to estimate the genetic diversity of cassava accessions for root and starch granule characteristics to guide the future industrial application of this species. Starches from 56 accessions were evaluated for the number of granules in 1 g of starch (NTG), area (AG, µm2), length (LG, µm), width (WG, µm), starch granule roundness (Round), dry matter content in the roots (DMC, %), pulp color (PulCo), and cyanogenic compounds (HCN). Images captured by light microscopy were used to determine the average phenotypic values, and these were further analyzed by principal component analysis (PCA) considering mixed data (quantitative and qualitative). Significant differences between the cassava accessions for all traits measured revealed wide variability in starch granule characteristics. Four diversity groups with better fitness for the classification of cassava accessions based on PulCo were identified, in comparison with HCN. Accessions with differential starch characteristics were identified, and crossings for the generation of segregating populations in order to obtain table and industry varieties have been proposed.

Polymorphism of starch pathway genes in cassava.

The distribution and frequency of single nucleotide polymorphisms (SNPs) can help to understand changes associated with characteristics of interest. We aimed to evaluate nucleotide diversity in six genes involved in starch biosynthesis in cassava using a panel of 96 unrelated accessions. The genes were sequenced, aligned, and used to obtain values for nucleotide diversity (π), segregating sites (θ), Tajima's D test, and neighbor-joining (NJ) clustering. On average, one SNP per 147 and 171 bp was identified in exon and intron regions, respectively. Thirteen heterozygous loci were found. Three of seven SNPs in the exon region resulted in non-synonymous replacement or four synonymous substitutions. However, no associations were noted between SNPs and root dry-matter content. The parameter π ranged from 0.0001 (granule bound starch synthase I) to 0.0033 (α-amylase), averaging 0.0011, while θ ranged from 0.00014 (starch branching enzyme) to 0.00584 (starch synthase I), averaging 0.002353. The θ diversity value was typically double that of the π. Results of the D test did not suggest any evidence of deviance of neutrality in these genes. Among the evaluated accession, 82/96 were clustered using the NJ method but without a clear separation of the root dry-matter content, root pulp coloration, and classification of the cyanogenic compound content. High variation in genes of the starch biosynthetic pathway can be used to identify associations with the functional properties of starch for the use of polymorphisms for selection purposes.

[Survey of anti-Leptospira agglutinins in workers from the city of Londrina-Paraná, Brazil]. / Pesquisa de aglutininas anti Leptospira en trabalhadores da cidade de Londrina-Paraná, Brasil.

Serum samples were obtained from 249 individuals in Londrina-Paraná, Brazil. The sera were analysed for leptospiral agglutinins by microscopic agglutination tests and 22.1% were positive. Of these positives per group were 24.6% for butchers, 25.9% for farm workers, 17.2% for children and 22.2% for servants. The agglutinin titers ranged from 1:200 to 1:3200. The highest titers were obtained for the serovars sejroe (butchers), grippotyphosa (farm workers), javanica, canicola, panama, wolffi and pyrogenes (children) and butembo (servants).

Pesquisa de aglutininas antileptospira em diferentes grupos profissionais na cidae de Londrina, Paraná / Anti-Leptospira agglutinins research in different professional groups in the city of Londrina, Paraná

Realizou-se um levantamento soroepidemiológico na cidade de Londrina - Paraná, para leptospirose, em 49 indivíduos näo expostos a risco, 75 trabalhadores da limpeza pública, 55 indivíduos com atividade em ambiente hospitalar e 29 trabalhadores do departamento de Agua e Esgoto. Dos 208 soros analisados pela reaçäo de soroaglutinaçäo microscópica, 28,4 por cento apresentaram aglutininas antileptospira. A maior positividade foi encontrada nos soros dos trabalhadores da limpeza pública (46,7 por cento)

[Anti-Leptospira agglutinins in different professional groups in the city of Londrina, Paraná]. / Pesquisa de aglutininas antileptospira em diferentes grupos profissionais na cidade de Londrina, Paraná.

Serum samples were obtained from 208 individuals in Londrina, Paraná, Brazil. The serum were analysed for leptospiral agglutinins by agglutination microscopic tests and 28.4% were positive. The highest positivity was found for the serum of garbage collector (46.7%).