Spartaco Astolfi Filho

Molecular marker-mediated validation of morphologically defined landraces of Pejibaye (Bactris gasipaes) and their phylogenetic relationships

RAPD markers were used to evaluate the genetic variability and structure of seven morphologically defined landraces of pejibaye (Bactris gasipaes Kunth, Palmae) to determine their validity and phylogenetic relationships. Two hundred and twenty plants of four Amazonian and three Central American landraces of var.gasipaes (the domesticate) and 30 plants of var.chichagui (H. Karsten) Henderson (the crop ancestor) maintained at the National Research Institute for Amazonia, Manaus, Amazonas, Brazil, were utilized. Eight RAPD primers yielded 113 markers, with good reproducibility, of which 97 were polymorphic. The four Amazonian landraces had an average heterozygosity of 0.30, with 86% polymorphism, greater than the Central American landraces (0.25; 74.3%) and var.chichagui (0.27; 80%). Among landrace genetic diversity (GST) was 15%, while within (Hs) was 85%, essentially equivalent to the AMOVA within (82.2%) and among (17.8%) variances. The Jaccard similarities, PCA, gene flow coefficients and Exact tests suggested that only one landrace exists in Central America, called Utilis after the first taxon described there, and that the Solimões landrace is part of the Putumayo landrace, rather than a separate entity. The Pará and Pampa Hermosa landraces were validated in accordance with their morphometric interpretations. The dendrogram of Nei’s genetic distances among valid landraces and var.chichagui supported the hypothesis of a single origin for pejibaye in southwestern Amazonia, with two migration routes: one to the northeast, becoming the Pará landrace, and another to the northwest along the Andes, spreading into western Amazonia (Pampa Hermosa and Putumayo landraces) and across the Andes, reaching Central America (Utilis landrace).

Detection of isometric, dsRNA-containing viral particles in Colletotrichum gloeosporioides isolated from cashew tree

Fungi are disease-causing agents in plants and affect crops of economic importance. One control method is to induce resistance in the host by using biological control with hypovirulent phytopathogenic fungi. Here, we report the detection of a mycovirus in a strain of Colletotrichum gloeosporioides causing anthracnose of cashew tree. The strain C. gloeosporioides URM 4903 was isolated from a cashew tree (Anacardium occidentale) in Igarassu, PE, Brazil. After nucleic acid extraction and electrophoresis, the band corresponding to a possible double-stranded RNA (dsRNA) was purified by cellulose column chromatography. Nine extrachromosomal bands were obtained. Enzymatic digestion with DNAse I and Nuclease S1 had no effect on these bands, indicating their dsRNA nature. Transmission electron microscopic examination of extracts from this strain showed the presence of isometric particles (30-35 nm in diameter). These data strongly suggest the infection of this C. gloeosporioides strain by a dsRNA mycovirus. Once the hypovirulence of this strain is confirmed, the strain may be used for the biological control of cashew anthracnose.

Chlamydia trachomatis infection in a sample of northern Brazilian pregnant women: prevalence and prenatal importance

UNLABELLED There are limited data regarding prevalence of Chlamydia trachomatis infection among northern Brazilian pregnant women. OBJECTIVE The purpose of this study was to estimate the prevalence of chlamydial infection among pregnant women in their third trimester and to determine the repercussion of this infection on their offspring. METHODS In the first phase of this study 100 pregnant women receiving prenatal care in a local public university hospital were examined to assess the prevalence of genital C. trachomatis infection by polymerase chain reaction technique. In the second phase, 88 pregnant women were prospectively evaluated for premature rupture of membranes, puerperal consequences associated with chlamydial infection, and neonates were checked for low-birth weight. RESULTS The prevalence rate of chlamydial infection was 11%, and 72.7% of the positive participants were predominantly less than 30 years of age (p=0.1319). A total of 36.4% of the participants had premature rupture of membranes (p=0.9998). Neither low-birth weight infants nor preterm delivery were observed. A cohort of 16 newborn babies were followed-up up to 60 days of life to ascertain outcome: 50% had respiratory symptoms. Neonates born to infected mothers had a higher risk to develop respiratory symptoms in the first 60 days of life. CONCLUSION The scarcity of data about the effects of chlamydial infection on pregnancy and neonatal outcomes justified this study. Diagnosing and treating chlamydial infection during the third trimester of pregnancy may prevent neonate infection. Therefore, preventive screening should be seen as a priority for early detection of asymptomatic C. trachomatis infection as part of local public health strategies.

Variabilidade genética e fluxo gênico em populações híbridas e silvestres de pupunha acessada com marcadores RAPD

The hybrid populations of peach palm (Bactris gasipaes Kunth) have accumulated genetic variability from adjacent landraces, which is expected to increase their variability. To test this hypothesis, 176 plants maintained in the peach palm Germplasm Bank at INPA, including four hybrid populations [Belem (n=26); Manaus (n=38); Iquitos, Peru (n=41); Yurimaguas, Peru (n=41)], two wild populations (B. gasipaes variety chichagui) types 1 (n=21) and 3 (n=7), and two samples of a related species, B. riparia, were genotyped with RAPD markers and compared to adjacent landraces reported in other studies. Eight RAPD primers generated 88 polymorphic and 11 monomorphic markers. The replicability test presented a Dice similarity of 0.67, considered acceptable. The average heterozygosity of the hybrid populations was 0.34 and the polymorphism was 87.9%, greater than in the wild populations (0.31; 74.7%). The dendrogram of Dice similarities did not present groups that clearly correspond to the hybrid populations. The gene flow between Iquitos and Yurimaguas (Nm=12.75), and between Iquitos and Manaus (Nm=9.47) was high, while between Belem and Manaus it was lower than expected (Nm=7.72), probably due to the influence of the Solimoes landrace near Manaus. The high value of heterozygosity in Manaus seems to be the result of the union of two dispersals after domestication: the western Amazonian dispersal, with Iquitos and Yurimaguas, and the eastern Amazonian, with Belem, joining in Manaus. However, these hybrid populations did not present an accumulation of genetic variability expressive enough to differentiate them from the landraces.

Genetic transformation to integrate two expression cassettes into the genome of yeast Pichia pastoris

Background Pichia pastoris is a methylotrophic species of yeast, which means that it can grow on methanol as its sole carbon and energy source [1]. The Pichia expression system has several advantages: short length of the oligosaccharide chains added to proteins, correct folding and very high cell densities [2]. P. pastoris vectors are designed for homologous integration into either AOX I locus, one of the two homologous AOX I genes present in this species or his4 locus. Gene insertion events at the AOX I (GS115) loci arise from a single crossover events between the loci and any of the three AOX I regions in the vector, the AOX I promoter, the AOX I transcription termination region (TT), or sequences even further downstream of AOX I (3′ AOX I) [3]. In either GS115 gene insertion events at his4 locus arise from a single crossover event between his4 locus in the chromosome and His4 gene of the vector. This results in the insertion of one or more copies of the vector in his4 locus [3].

Cloning and expression of lipase gene from Ralstonia eutropha in Escherichia coli

Background Lipases are enzymes belonging to the class of hydrolases, acting in the aqueous-organic interface demonstrating considerable levels of activity and stability in aqueous environments and non-aqueous [1]. Its biological function is to catalyze the hydrolysis of long chain triglycerides to form fatty acids and glycerol, in addition to performing esterification [2]. They have wide industrial applicability and can be used in the composition of detergents, in food industry, in wastewater treatment and fine chemistry [3]. The goal this work was clone and express lipase gene from Rasltonia eutropha in Escherichia coli BL21DE3.