Prevalence study of SNP c.421G>T in the ADAMTS2 gene responsible for dermatosparaxis in White Dorper sheep in Brazil

Abstract: Dermatosparaxis is an autosomal recessive disorder of connective tissue; the disorder is clinically characterized by skin fragility and hyperextensibility. Dermatosparaxis in White Dorper sheep is caused by a single nucleotide polymorphism (SNP) (c.421G>T) in the ADAM metalloproteinase with thrombospondin type 1 motif, 2 (ADAMTS2) gene. The aim of this study was to investigate the prevalence of this SNP in a White Dorper herd in São Paulo state, Brazil. In this study, we collected blood DNA samples from 303 White Dorper sheep and performed polymerase chain reaction to amplify the SNP region. The samples were sequenced to determine the presence of the SNP in the ADAMTS2 gene. The SNP prevalence in the studied population was 15.5%; this finding indicates that more effective control measures should be used to prevent the inheritance of SNP c.421G>T in the ADAMTS2 gene in Brazilian White Dorper herds.

Floral biology and breeding system of three Ipomoea weeds

The floral biology of three weeds, Ipomoea cairica, I. grandifolia and I. nil (Convolvulaceae), was studied in Botucatu and Jaboticabal, São Paulo, in southeastern Brazil. The three species are melittophilous, with a varied set of floral visitors, but with some overlapping. Cluster analysis using Jacquard similarity index indicated a greater similarity among different plant species in the same locality than among the populations at different places, in relation to floral visitor sets. The promiscuous and opportunistic features of the flowers were shown, with such type of adaptation to pollination being advantageous to weeds since pollinator availability is unpredictable at ruderal environments.

Alternative procedures for parent choice in a breeding program for the common bean (Phaseolus vulgaris L.)

Six common bean cultivars were crossed in diallel and the segregant populations were assessed in the F2 and F3 generations to compare methodologies for parental selection in a breeding program based on hybridization. The cultivars involved in the diallel were A 114, A 77, ESAL 686, Milionário, Carioca, and Flor de Mayo. The segregant F2 and F3 generations were assessed on the experimental campus of the Universidade Federal de Larvas, in July 1994. It was found that the cultivars differed in their general combining ability (GCA). Flor de Mayo, which belongs to the Durango race, had the largest positive GCA estimate for grain field, and the cultivars from the Mesoamerican race, Milionário and A 114, the smallest GCA estimates. For flowering, the cultivar that most contributed to reduced plant cycle was ESAL 686. There was agreement among the results obtained from the diallel and the estimates of the parameter m + a of the populations. However, it was evident that the estimate of genetic variance of the populations should be considered as a condition to identify the hybrid population that will produce a line with high performance.

Evaluation of Petrifilm™ system compared with traditional methodology in count of indicators of sanitary-hygienic quality and pathogenic microorganisms in sheep milk

The objective of this study was to evaluate the applicability of the Petrifilm™ plates to enumerate microbial groups in sheep milk. Samples of sheep milk (n = 30) were plated simultaneously, to enumerate mesophilic aerobes, total coliforms, lactic acid bacteria, Staphylococcus aureus and Escherichia coli, using convencional reference protocols and Petrifilm™ plates. The results were compared using McNemar's test, linear regression and ANOVA (p < 0,05). The results demonstrated good significant between conventional methodologies and Petrifilm™ plates. Further, the Petrifim™ STX for counting S. aureus had higher recoverability of bacteria compared with the conventional methodology. Based on the results obtained and in view of the ease and rapidity procedures results, Petrifim ™ plates may be considered as alternatives for microbiological testing in sheep milk.