Cristina Soares de Sousa

Esterase enzymes involved in pyrethroid and organophosphate resistance in a Brazilian population of Riphicephallus (Boophilus) microplus (Acari, Ixodidae).

Esterases are a group of enzymes that are reportedly associated with acaricide resistance in Riphicephallus (Boophilus) microplus. A comparative analysis was made of the esterase patterns in malathion and deltamethrin-sensitive, tolerant and resistant tick groups, using non-denaturing polyacrylamide gel electrophoresis. Electrophoretical profiles revealed four bands of esterase activity against alpha-naphthyl acetate; which were dubbed EST-1 to EST-4. The EST-3 and EST-4 were detected in all strains and were classified as carboxylesterases (CaEs). The EST-2, classified as an acetylcholinesterase (AChE), was detected in all groups, but its staining intensity increased from susceptible to resistant groups, indicating an altered production according to the degree of resistance. EST-1, which was also classified as an AChE, was detected exclusively in tolerant and resistant groups to both acaricides, but displayed greater activity in the malathion-resistant group. These data suggest that these AChEs may represent an important detoxification strategy developed to overcome the effects of acaricides.

Insights into the Melipona scutellaris (Hymenoptera, Apidae, Meliponini) fat body transcriptome

The insect fat body is a multifunctional organ analogous to the vertebrate liver. The fat body is involved in the metabolism of juvenile hormone, regulation of environmental stress, production of immunity regulator-like proteins in cells and protein storage. However, very little is known about the molecular mechanisms involved in fat body physiology in stingless bees. In this study, we analyzed the transcriptome of the fat body from the stingless bee Melipona scutellaris. In silico analysis of a set of cDNA library sequences yielded 1728 expressed sequence tags (ESTs) and 997 high-quality sequences that were assembled into 29 contigs and 117 singlets. The BLAST X tool showed that 86% of the ESTs shared similarity with Apis mellifera (honeybee) genes. The M. scutellaris fat body ESTs encoded proteins with roles in numerous physiological processes, including anti-oxidation, phosphorylation, metabolism, detoxification, transmembrane transport, intracellular transport, cell proliferation, protein hydrolysis and protein synthesis. This is the first report to describe a transcriptomic analysis of specific organs of M. scutellaris. Our findings provide new insights into the physiological role of the fat body in stingless bees.

Divergência genética entre genótipos de alface por meiode marcadores AFLP

Considering the restricted diversity of species available to counteract vitamin deficiencies in Brazil, Kerr and coworkers have been engaged since 1981, in developing genetic improved garden vegetables rich in vitamin A. One of these vegetables is the lettuce cultivar Uberlândia 10,000, which contains 10,200 UI of vitamin A per 100 grams of fresh leaves. This study compares the genetic diversity between Uberlândia 10,000 and its parental, evaluating selection efficiency through the AFLP technique. The following lettuce genotypes were used for this comparison: Maioba, Salad Bowl-Mimosa, Moreninha-de-Uberlândia, Vitoria de Santo Antao, smooth 8th and 9th generation Uberlândia 10,000, and crinkly 8th and 9th generation Uberlândia 10,000 cultivars. The AFLP technique was effective for identifying very close genotypes and for studying lettuce progenies. The primer PR15 enabled the separation of smooth and crinkly types down to 1.8% of genetic diversity and the 8th and 9th generations down to only 0.71% of diversity. Phylogenetic study of the cultivar confirmed the success of the breeding program, with the Uberlândia 10,000 cultivar revealing high vitamin A content and 92% of similarity with the parental Vitoria de Santo Antao. The primer PR11 allowed the identification of polymorphism between cultivars with high and low resistance to septoriosis, suggesting that these bands may be resistance-related.

Mancha de Septoria da alface: isolamento, inoculação e avaliação de cultivares em condições de campo e casa de vegetação

ABSTRACT Lettuce Septoria leaf spot: isolation, inoculation, cultivarevaluation in field and greenhouse conditions The objectives of this work were to establish appropriatemethodologies for isolation and inoculation of Septoria lactucae inorder to evaluate resistance. Nine lettuce ( Lactuca sativa ) cultivars(Vitoria-de-Santo-Antao, Uberlândia 10.000, Maioba, Elba, Aurelia,Black Seeded Simpson, Grand, Rapids, Salad Bowl-Mimosa andBaba de Verao) were screened for resistance to this pathogen undergreenhouse and field conditions. The best results obtained were: a)for isolation: to transfer cirrus of conidia directly to the surface ofPetri dishes with PDA medium plus antibiotics (streptomycin,chloramphenicol, ampicilim and riphampicin); b) for inoculation:to spray plants of six to eight leaves with a conidia suspension of1 x 10 4 spores/ml and keep them in a moist chamber for 48 h.Significant differences were found among cultivars both ingreenhouse and field tests. Under both conditions the cultivarsMaioba and Vitoria de Santo Antao were found to be, respectively,the most susceptible and the most resistant cultivars among thosetested. From these results, the greenhouse test methodology isseen to ge highly promising for the rapid screening of a greatnumber of genotypes in breeding programs of lettuce resistant to