Resumo em Inglês:

We used the multiplex semi-quantitative reverse-transcriptase PCR (RT-PCR) to investigate kallikrein 2 and 3 (KLK2 and KLK3) mRNA levels in prostate tissue from 42 prostate cancer patients, 33 of whom were also assessed for peripheral blood KLK2 expression by qualitative semi-nested RT-PCR. We found that KLK2 was an important tissue biomarker for distinguishing between prostate cancer patients and those with benign prostatic hyperplasia, particularly when KLK2 expression was > 60% of that of the beta2-microglobulin constitutive gene. Patients with an average relative expression value > 0.6 (cutoff value) had an eleven-fold higher chance of having prostate cancer. When one or two tissues samples were evaluated for KLK2 expression using the cutoff value the estimated chance of having prostate cancer was increased by seven times for one positive sample and 45 times for two positive samples. There was no significant correlation between KLK3 gene expression and prostate cancer diagnosis. Logistic regression for blood and tissue KLK2 expression successfully detected 92% of the prostate cancer cases. The detection of KLK2 in blood showed a sensitivity of 59% and a specificity of 82%. This study indicates that the KLK2 gene may be a useful molecular marker for the diagnosis of prostate cancer and that analysis of KLK2 expression in blood and tissues could provide a novel approach for the clinical investigation of this type of cancer.

Resumo em Inglês:

We report the clinical and laboratory findings concerning three unrelated Brazilian patients investigated for polycythemia, whose definitive diagnosis could only be established after the presence of Hb Coimbra (b99 Asp ® Glu) was demonstrated. This illustrates the importance of properly investigating hereditary hemoglobinopathies in cases of erythrocytosis because in some populations variants with high oxygen affinity may be more frequent than expected but go undetected when conventional electrophoresis is used as the sole detection procedure.

Resumo em Inglês:

We established a specific genotyping assay for HLA-A*01, which is one of the most frequently found HLA-A alleles in the Caucasian population. This assay uses the polymerase chain reaction (PCR) with allele group-specific primers (ASP). HLA-A*01 group-specific primers were designed for exon 3 of the HLA-A gene, based on the recent HLA-sequence alignment. Both sense and anti-sense primers were designed with completely matched sequences to each specific HLA-A*01 allele, but mismatched by at least 1 nucleotide to all other known class I HLA alleles. By the use of these primers and stringent PCR conditions, we successfully genotyped the HLA-A*01 group alleles and achieved greater accuracy than previous methods.

Resumo em Inglês:

Conservation genetics has been focused on the ecological and evolutionary persistence of targets (species or other intraspecific units), especially when dealing with narrow-ranged species, and no generalized solution regarding the problem of where to concentrate conservation efforts for multiple genetic targets has yet been achieved. Broadly distributed and abundant species allow the identification of evolutionary significant units, management units, phylogeographical units or other spatial patterns in genetic variability, including those generated by effects of habitat fragmentation caused by human activities. However, these genetic units are rarely considered as priority conservation targets in regional conservation planning procedures. In this paper, we discuss a theoretical framework in which target persistence and genetic representation of targets defined using multiple genetic criteria can be explicitly incorporated into the broad-scale reserve network models used to optimize biodiversity conservation based on multiple species data. When genetic variation can be considered discrete in geographical space, the solution is straightforward, and each spatial unit must be considered as a distinct target. But methods for dealing with continuous genetic variation in space are not trivial and optimization procedures must still be developed. We present a simple heuristic and sequential algorithm to deal with this problem by combining multiple networks of local populations of multiple species in which minimum separation distance between conserved populations is a function of spatial autocorrelation patterns of genetic variability within each species.

Resumo em Inglês:

The Saguinus represent the basal genus of the Callitrichinae subfamily. Traditionally this genus is divided into three groups: Hairy, Mottled and Bare-face, however, molecular data failed to validate these groups as monophyletic units, as well as raised some subspecies to the species status. This is the case of the former subspecies Saguinus midas midas and S. midas niger, which are now considered as different species. In the present study, we sequenced a portion of the D-loop mtDNA region in populations from the East bank of the Xingu and from both banks of the Tocantins river, in order to test the effectiveness of large rivers as barriers to the gene flow in Saguinus. According to our results, the populations from the East and West banks of the Tocantins river are more divergent than true species like S. mystax and S. imperator. The Tocantins river may be acting as a barrier to gene flow, and consequently these very divergent populations may represent distinct taxonomic entities (species?).

Resumo em Inglês:

The genetic structure of Caiman crocodilus was investigated using a 1085 bp mtDNA fragment of the cytochrome b gene. Inferences were based on 125 individuals from nine localities in Peru, Brazil and French Guiana. With the exception of Mamirauá Lake, Anavilhanas Archipelago and the Tapará Community which show a signal of demographic expansion, the sampled localities are in a mutation-drift genetic equilibrium. Divergence between the Amazon basin and extra-Amazon basin localities is significant; however, inference from Nested Clade Analysis cannot distinguish between continuous range expansion, long distance colonization or past fragmentation; however, past fragmentation is unlikely due to low number of mutational steps separating these two regions. The divergence is probably maintained by the reduced ability of C. crocodilus to cross salt water barriers. Within the Amazon basin, continuous range expansion without isolation-by-distance is the most likely process causing genetic structuring. The observed genetic patterns are compatible with the ecology of C. crocodilus, and history of human exploitation. As commercial hunting depleted more valuable species, C. crocodilus expanded its range and ecological niche, prompting hunters to harvest it. Following a period of intense hunting, C. crocodilus is now experiencing recovery and a second population expansion especially in protected areas.

Resumo em Inglês:

The selection of molecular markers for population studies is an important tool for biodiversity conservation. The family Psittacidae contains many endangered and vulnerable species and we tested three kinds of molecular markers for their potential use in population studies of five psitacid species: 43 hyacinth macaws (Anodorhynchus hyacinthinus), 42 blue-and-yellow macaws (Ara ararauna), 23 red-and-green macaws (Ara chloroptera), 19 red-spectacled amazons (Amazona pretrei); and 18 red-tailed amazons (Amazona brasiliensis). We tested 21 clones from a genomic library of golden conure (Guarouba guarouba) minisatellites and 12 pairs of microsatellite primers developed for the domestic chicken (Gallus gallus) and A. hyacinthinus. We also tested seven tetranucleotide repeat primers for their ability to amplify regions between microsatellite loci (inter simple sequence repeats, ISSRs). We were able to select seven markers that were variable in different degrees for three species (A. hyacinthinus, A. chloroptera and A. ararauna). The mini and microsatellites produced more polymorphic patterns than the ISSRs. The genetic variability of the species studied seems to be correlated with their endangered status.

Resumo em Inglês:

We used mitochondrial DNA (mtDNA) sequences to investigate the demographic history of the wood stork (Mycteria americana) populations in the Brazilian Pantanal. Sequences of 390/460 bp fragment of the mtDNA control region were analyzed in 62 wood stork specimens from 8 colonies using neutrality tests, phylogeographic, and coalescent analyses. Population expansion was supported by the significantly negative values of Tajima’s (D = -2.071) and Fu’s (Fs = -14.544) statistics and the unimodal pattern of mismatch distribution. Nested clade analyses indicated a historic range expansion event and recurrent gene flow that was restricted by isolation by distance as explanations for the haplotype distribution among the sampled colonies. High genetic diversity and the strictly unidirectional gene flow pattern emphasized the conservation importance of preserving the southern Pantanal colonies. Coalescence analyses suggested that northern and southern colonies diverged approximately 6,250 years before the present (YBP), and that their most recent common ancestor was approximately 18,900 YBP. Our results suggest that the contemporary wood stork Pantanal population originated from a more geographically limited founder population. Potential source populations may have occurred in the southern Pantanal or ancestry may reside in populations inhabiting the Brazilian central plateau or areas closer to the equatorial region.

Resumo em Inglês:

The 5S ribosomal DNA (5S rDNA) of higher eukaryotes is organized in repeat units of tandem arrays composed of a 5S rDNA coding region, conserved even among non-related taxa, and a variable non-transcribed spacer sequence (NTS). To contribute to knowledge on the organization and evolution of vertebrate 5S rDNA we used PCR, nucleotide sequencing, Southern blot hybridization and chromosome fluorescence in situ hybridization (FISH) to investigate 5S rDNA tandem repeats in the South American Curimatidae fish Steindachnerina insculpta and Cyphocharax modesta. 5S rDNA repeats of 180 base pairs (bp) from both species were PCR-generated and sequenced evidencing the shortest 5S rDNA monomer so far described in eukaryote species. Southern blotting revealed that both species contained two tandem 5S rDNA classes, the PCR amplified fragment composed of 180 bp monomers and a class of 1600 bp monomers not detected by PCR. Chromosome mapping of the 5S rDNA repeats identified a major locus in both species and a second minor locus only in C. modesta. The Southern blot and chromosome mapping data indicate the presence of different types of 5S rDNA tandem repeats in the Curimatidae genome.

Resumo em Inglês:

We report on the presence of B-chromosomes in two populations of Dendropsophus nanus (= Hyla nana Boulenger, 1889) from São Paulo State, Brazil. Such chromosomes were observed in 4 out of 43 specimens (9.3%) and in 9 out of 15 specimens (60%) from the municipalities of Nova Aliança and Botucatu, respectively. The karyotype 2n = 30 + 1B found in D. nanus was similar to that of other species with 2n = 30 chromosomes, except for the presence of an additional small telocentric chromosome. In one specimen from Botucatu, cells with one to three extra chromosomes were observed. These B-chromosomes appeared as univalent in meiosis I and did not bear a nucleolar organizer region or exhibit constitutive heterochromatin.

Resumo em Inglês:

We present the karyotypic characterization of 26 specimens of the side-necked turtle Hydromedusa tectifera collected in the upper Iguaçu River, Paraná state, Brazil. The turtles were cytogenetically analyzed using Giemsa staining and other banding techniques (C, G, Ag-NOR and CMA3) as well as fluorescence in situ hybridization (FISH) with a rDNA 18S probe. All the specimens showed a diploid number of 58 composed of 22 macro and 36 microchromosomes. The Ag-NOR, CMA3 and FISH techniques permitted the identification and characterization of the chromosome pairs bearing nucleolus organizer regions (NORs), while G-banding facilitated a better recognition and pairing of macrochromosomes. These data agree with some information available in the literature and should be very useful for further cytotaxonomic and cytosystematic studies.

Resumo em Inglês:

The Uruguayan Creole cattle genetic reserve consists of a herd of about 600 animals (bulls, cows and calves) located in an indigenous habitat of 650 hectares. In a previous study, a random sample from this herd showed high heterozygosity and a Hardy-Weinberg equilibrium for markers of major genes related to milk production. To study its genetic diversity we genotyped a sample of bulls (N = 19 out of 23 for the whole herd) using the PCR reaction with a set of 17 microsatellite markers. Between two and seven different alleles were identified per microsatellite in a total of 73 alleles. The expected mean heterozygosity (He) per locus was between 0.465 and 0.801, except for microsatellite HEL13 which gave a He value of 0.288. The expected mean heterozygosity was 0.623 and the polymorphic information content (PIC) was between 0.266 for HEL13 and 0.794 for CSSM66. The genetic diversity found in polymorphic markers in the breeding bulls of this Creole cattle population supports previous genetic analyses using major production genes and indicate that further studies should be carried out on this population to provide data of interest to cattle production.

Resumo em Inglês:

Estrogen has an important function in swine reproduction and growth. A Pvu II restriction enzyme polymorphism has been proven to be an important genetic variation in the estrogen receptor gene (ESR) and may be considered as a candidate gene for use in pig production but there is no data regarding the prevalence of this polymorphism in the Brazilian pig population. We used DNA samples from the following three purebred pig breeds: Large White (336 females and 26 males), Landrace (304 females and 27 males) and Pietrain (125 females and 11 males). The ESR genotyping was performed using PCR-RFLP. For each breed, genotypes for the ESR gene were compared independently for expected progeny differences (EPD) in litter size (LS), average daily weight gain (DWG) (g/day) and back fat thickness (BT) as measured in mm by ultrasound. In the Large White breed, but not the other breeds, the ESR genotype was significantly (p < 0.05) associated to LS, DWG and BT. Large Whites genotyped as AA or AB had higher EPD values for the LS and BT traits compared to BB Large Whites, while AA Large Whites had higher DWG EPD values than BB Large Whites. Our results for the Large White population showed that the A allele has a beneficial effect on LS, DWG and BT expected progeny differences.

Resumo em Inglês:

Cytogenetic analysis of Trichomycterus areolatus, collected from the Tijeral and Huilma Rivers in southern Chile has shown a diploid chromosome number of 2n = 54, a fundamental number of FN = 106, and a karyotypic formula of 44m + 8sm + 2st. Intra-individual polymorphism of chromosome number (2n = 54, 55 and 56) in specimens from the Huilma River has also been documented, providing further evidence of the occurrence of this phenomenon in Trichomycterus. The karyotype exhibited large chromosome pairs: metacentric pairs 1 (relative length 7.54%), 2 (5.75%) and 3 (5.09%), submetacentric pair 23 (5.25%), and subtelocentic pair 27 (5.28%). Nuclear DNA content analysis showed an average value of 5.04 ± 1.09 pg/nucleus. This DNA content is higher than the mean value described for other species in this genus.

Resumo em Inglês:

Previous cytochrome B (CytB) mtDNA studies have suggested four species for the opossum genus Philander (four-eyed opossums), three (P. mcilhennyi, P. andersoni and P. opossum) from the Amazon and one (P. frenata) from the Brazilian Atlantic forest. During a faunal survey nine specimens of Philander sp. and four of Didelphis marsupialis were collected in the Mamirauá Sustainable Reserve, Amazonas State, Brazil. Preliminary analyses based on morphology and geographical distributions were not conclusive, suggesting that Philander specimens could belong to either P. andersoni or P. opossum. In order to elucidate the relationship of this taxon to the remaining Amazonian taxa, seven Philander and two Didelphis specimens animals were sequenced for the cytB mtDNA gene and compared to other previously studied taxa. The maximum likelihood (ML), neighbor-Joining (NJ) and maximum parsimony (MP) consensus bootstrap trees depicted six groups: Didelphis., P. frenata, P andersoni, P. mcilhennyi, P.o. opossum and Philander sp. and Philander canus in a common assemblage supported by significant bootstrap values, suggesting that the Philander sp. from Mamiraua in fact belongs to the species Philander canus.

Resumo em Inglês:

The genetic diversity of Jamunapari goats (Capra hircus) was investigated using an optimized non-radioactive polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) method to detect <FONT FACE=Symbol>a</font>-lactalbumin polymorphism in a sample of 50 goats. Our data show that PCR-SSCP is an appropriate tool for evaluating genetic variability in Jamunapari goats. Polymorphism was detected in the sample, indicating that Jamunapari goats have high genetic variability at loci, exon I of the a-lactalbumin gene. This result opens interesting prospects for future selection programs and conservation strategies. These a-lactalbumin variants can be sequenced and screened in the population to develop single nucleotide polymorphism (SNP) markers for association studies and marker assisted selection.

Resumo em Inglês:

We used four microsatellite loci (Fca08, Fca45, Fca77 and Fca96) from the domestic cat, Felis catus, to investigate genetic variability in specimens of Herpailurus yagouaroundi (jaguarundi, otter cat, eyra), Puma concolor (cougar, mountain lion, puma) and Panthera onca (jaguar) held in various Brazilian zoos. Samples of DNA from the cats were PCR amplified and then sequenced before being analyzed using the CERVUS program. Our results show a mean polymorphic information content (PIC) of 0.83 for H. yagouaroundi, 0.66 for P. concolor and 0.69 for P. onca and a mean of 10.3 alleles for the Fca08 locus, 5.3 for Fca 45, 9 for Fca 77 and 14 for Fca 96. These results indicate a relatively high level of genetic diversity for the specimens studied.

Resumo em Inglês:

Microsatellites, or simple sequence repeats (SSRs), have been the most widely applied class of molecular markers used in genetic studies, with applications in many fields of genetics including genetic conservation, population genetics, molecular breeding, and paternity testing. This range of applications is due to the fact that microsatellite markers are co-dominant and multi-allelic, are highly reproducible, have high-resolution and are based on the polymerase chain reaction (PCR). When first introduced, the development of microsatellite markers was expensive but now new and efficient methods of repetitive sequence isolation have been reported, which have led to reduced costs and microsatellite-technology has been increasingly applied to several species, including non-model organisms. The advent of microsatellite markers revolutionized the use of molecular markers but the development of biometric methods for analyzing microsatellite data has not accompanied the progress in the application of these markers, with more effort being need to obtain information on the evolution of the repetitive sequences, which constitute microsatellites in order to formulate models that fit the characteristics of such markers. Our review describes the genetic nature of microsatellites, the mechanisms and models of mutation that control their evolution and aspects related to their genesis, distribution and transferability between taxa. The implications of the use of microsatellites as a tool for estimating genetic parameters are also discussed.

Resumo em Inglês:

We presented an alternative way to verify the relative contribution to the total variance, of the sources of variation due to populations (P), individuals within populations (I), the (P*I) interaction, and the standard error of the following parameter estimates: total (F) and intrapopulation (f) fixation indices, and divergence among populations (q). The knowledge of this relative contribution is important to establish sampling strategies of natural populations. To attain these objectives, the bootstrap method was used to resample simultaneously populations and individuals, considering different combinations of P and I. This procedure was repeated five times for a given combination of each analyzed data set. For each data set, five estimates of these variances were obtained for each combination of P and I, and a given parameter estimate. These variance estimates were submitted to an analysis of variance, considering a factorial structure. The sources of variation considered in this analysis were P, I and P*I. The coefficient of determination (R²) was calculated for each source of variation. Sources of variation with greater R² are responsible for bigger errors of the estimates. The method applied was efficient for answering the questions initially proposed, and the results indicated that there are no ideal sample sizes for a species, but rather for a specific data set, because each data set has its own particularities. However, for investigations on the genetic structure of natural populations using population parameters, the number of populations to be sampled is a critical factor. Thus, more efforts should be made to increase the number of sampled populations, rather than the number of individuals within populations. A sampling strategy is given as a guide for investigations of this kind, when there is no previous knowledge about the genetic structure and the mating system of the populations.

Resumo em Inglês:

Cold tolerance during germination is important for ensuring fast and uniform establishment of a rice crop early in the season. However, evaluation of this trait under field conditions is limited by environmental variation, which makes it difficult to identify genetically superior lines. Evaluation of cold tolerance under controlled temperature conditions may be performed by assessing percentage of reduction in coleoptile length and coleoptile growth. Our study determined the inheritance and heritability of cold tolerance at the germination stage in crosses between six rice genotypes. Diallel analysis showed that while both additive and non-additive gene action were involved, the non-additive action was relatively more important for percentage of reduction in coleoptile length and coleoptile growth. Our data shows that genotype Quilla 66304 would be the best parent in crosses aimed at increasing cold tolerance at the germination stage in rice due to its high general combining ability for both percentage of reduction in coleoptile length and coleoptile growth. Generation mean analysis was also performed for coleoptile growth in six cold-sensitive x cold-tolerant crosses and proved that non-additive effects were due to dominance and epistatic interactions. Though broad sense heritability values were high, the relative importance of the non-additive effects suggests that selection should be applied in advanced generations of the breeding program.

Resumo em Inglês:

Genetic diversity and the relationship between varieties are of great importance for cotton breeding. Our work was designed to estimate the informativeness of the cotton (Gossypium hirsutum L.) simple sequence repeat (SSR) microsatellite locus and to estimate the genetic distance between 53 cotton cultivars as well as to select a set of SSR primers able to differentiate between the 53 cotton cultivars studied. After extracting DNA from the 53 cultivars and characterized it using 31 pairs of SSR primers we obtained a total of 66 alleles with an average of 2.13 alleles per SSR locus and values of polymorphism information content (PIC) varying from 0.18 to 0.62, the dissimilarity coefficient varying from zero to 0.41. Statistical analysis using the unweighted pair-group method using arithmetic average (UPGMA) revealed seven subgroups which were consistent with the genealogical information available for some of the cultivars. The SSR genetic profile obtained for each of the cultivars made it possible to discriminate 52 of the 53 cultivars. This study of the genetic diversity of cotton cultivars with SSR markers support the need to introduce new alleles into the gene pool of the breeding cultivars.

Resumo em Inglês:

Cultivated six-rowed naked barley (Hordeum vulgare ssp. hexastichon var. nudum Hsü) is the oldest cultivated barley in China. We used 35 simple sequence repeat (SSR) markers selected from seven barley linkage groups to study the genetic diversity, geographical differentiation and evolutionary relationships among 65 H. vulgare ssp. hexastichon landrace accessions collected from the Qinghai-Tibet plateau of China, 25 accessions from Tibet (TB), 20 from Qinghai (QH) and 20 from Ganzi (GZ) prefecture in Sichuan province. At the 35 SSR loci we identified 248 alleles among the 65 accessions, 119 (47.98%) of the alleles being common alleles. We also found that the TB accessions possessed 47 private alleles, about 1.5 times more than the 31 private alleles found in the QH accessions and about 5 times more than 9 private alleles found in the GZ accessions. Generally, the TB accessions showed significantly higher genetic diversity than either the QH or GZ accessions whereas no significant difference in genetic diversity was found between the QH and GZ accessions. Partitioning analysis of genetic diversity showed that about 81% of the total variation was due to within-subgroup diversity and about 19% was clearly accounted for by geographical differentiation among the three subgroups. The distributions of alleles for most loci (71.4%) were significantly different among the three subgroups and geographical differentiation could be found according to the distribution of SSR alleles. Cluster analysis indicated that most of the accessions could be clustered into groups which basically coincided with their geographical distribution. These results suggest that Tibet might be a center of genetic diversity for cultivated barley, the cultivated six-rowed naked barley on the Qinghai-Tibet plateau of China may have evolved in Tibet and spread to Qinghai and then to Ganzi prefecture of Sichuan province.

Resumo em Inglês:

The plant Rhodiola crenulata is a perennial herbaceous species distributed in the plateau region of southwestern China, especially the Hengduan Mountains region. It has been one of the most important traditional herbal remedies in Tibet for more than one thousand years, but the accelerated and uncontrolled collection of this plant since the 1980s has lead to deforestation. We used inter-simple sequence repeats (ISSR) to assess levels of genetic variation in R. crenulata from nine diverse natural populations in eastern Tibet and northern Yunnan, the first time such a study has been carried out. The 12 primers we used were able to detect 184 polymorphic loc. Analysis of molecular variance (AMOVA) indicated that species level genetic diversity was relatively high (p = 97.83%, and Ho = 0.464) and analysis using Shannon’s index showed that the within and between genetic diversity of R. crenulata are approximately equal. Nei’s genetic distance and unweighted pair-group method with arithmetic averages (UPGMA) cluster analysis showed that the three populations from Tibet and the six populations from Yunnan form two major clusters. The Yunnan populations from three locations were further divided into three corresponding groups, indicating that genetic differentiation was correlated to geographic distribution. Understanding the genetic structure of R. crenulata provides insight for the conservation and management of this endangered species.

Resumo em Inglês:

The effect of natural selection on microsatellite simple sequence repeat (SSR) alleles was investigated in two distinct common bean (Phaseolus vulgaris) generations (F8 and F24) derived from the cross between the P. vulgaris cultivars Carioca MG x ESAL 686. The F2 segregant population was propagated by the bulk method and 107 plants were sampled in two generations (F8 and F24). Each plant generated one family which was replicated by the bulk method to F8:11 and F24:27 families from which DNA was extracted. Thirty pairs of microsatellite primers were polymorphic for the parents and the bulk of the F24:27 families. Out of 30 loci selected by natural selection, 29 microsatellite alleles came from the Carioca MG parent and one allele came from the ESAL 686 parent. Natural selection affected all the generations and its intensity was specific for each locus and generation. Therefore all the alleles selected at each locus must be important for adaptation in a breeding program.

Resumo em Inglês:

The cultivated and sexually compatible species Pennisetum purpureum (elephant grass, 2n = 4x = 28) and Pennisetum glaucum (pearl millet, 2n = 2x = 14) can undergo hybridization which favors the amplification of their genetic background and the introgression of favorable alleles into breeding programs. The main problem with interspecific hybrids of these species is infertility due to triploidy (2n = 3x = 21). This study describes meiosis in elephant grass x pearl millet hybrids and their progenitors. Panicles were prepared according to the conventional protocol for meiotic studies and Alexander’s stain was used for assessing pollen viability. Pearl millet accessions presented regular meiosis with seven bivalents and high pollen viability. For elephant grass, 14 bivalents in diakinesis and metaphase I were observed. The BAG 63 elephant grass accession, derived from tissue culture, presented a high frequency of meiotic abnormalities. The three hybrid accessions presented a high frequency of abnormalities characterized by irregular chromosomal segregation which resulted in the formation of sterile pollen.

Resumo em Inglês:

Bacterial beta-glucuronidase activity in the gut increases the enterohepatic circulation of toxic compounds and plays a major role in the etiology of colon cancer. Previously, we had found that the gus gene, which codes for beta-glucuronidase in a dominant anaerobic species of the gut microbiota, Ruminococcus gnavus strain E1, is transcribed as part of an operon that includes three ORFs that code for beta-glucoside permeases of the phosphotransferase systems. This genetic organization had never been described. We have now compared beta-glucuronidase activity and the genetic environment of the gus gene in 14 strains of Ruminococcus gnavus.We found that five out of the seven glucuronidase-positive R. gnavus strains possessed another glucuronidase gene different from the gusA operon of R. gnavus E1. This dominant commensal intestinal species appears to have a high degree of genetic diversity in the genes that control beta-glucuronidase activity.

Resumo em Inglês:

The human immunodeficiency virus (HIV) is classified as a retrovirus because of its RNA genome and the fact that it requires reverse transcriptase to convert it into DNA. This virus belongs to the lentivirinae subfamily and is able to infect quiescent cells but is better known for its association with acquired immunodeficiency syndrome (AIDS) and can be described as one of the most effective vectors for gene transfer. Biosafety concerns are present whenever viral vectors are employed but are particularly pertinent to the development of HIV-based vectors. Insertional mutagenesis and the production of new replication-competent viruses (RCV) have been pointed to as major problems, but experimental data have shown that safe protocols can be developed for their production and application. Virological, evolutionary, immunological and cell biology studies must be conducted jointly to allow the clinical use of HIV vectors. This review will focus on the general properties, production and applications of retrovectors in gene therapy, with particular emphasis on those based on HIV systems.

Resumo em Inglês:

Extracts of the fruits of Caesalpinia ferrea Mart. (Leguminosae) are widely consumed in folkloric medicine in Brazil and several other countries without any genetic toxicity evaluation. In this study we investigated, the clastogenic and cytotoxic potential of the crude aqueous extract of the fruits of C. ferrea in Wistar rat bone marrow cells using the micronucleus and chromosomal aberration test systems. The animals were treated by gavage with 3 concentrations of the extract, 500, 1000 and 1500 mg/kg, and cyclophosphamide 30 mg/kg. Bone marrow cells were collected 24 h after the treatment. There was no statistically significant difference in the mean of micronucleated polychromatic erythrocytes (MNPCE), mean number of chromosomal aberrations or mitotic index (MI) for the 3 concentrations compared with negative control suggesting that the crude aqueous extract from the fruits of the C. ferrea has no clastogenic and cytotoxic effect in Wistar rat bone marrow cells.

Resumo em Inglês:

Information about the distribution and insertion numbers of many transposable elements is restricted to few species of Drosophila, although these elements are widely distributed throughout the genus. The aim of this work was to describe the distribution and insertion numbers of four retrotransposons (copia, gypsy, micropia, I) and four transposons (hobo, mariner, Minos and Bari-1) in the saltans group of Drosophila. Our data shows that, except for mariner, all the other elements are widespread within the saltans group and show variable insertion numbers of up to 24 copies.

Resumo em Inglês:

The tropical mosquito, Aedes aegypti is the most important domestic vector of urban yellow fever and dengue. Genetic population studies on this vector are important because they may lead to new tools for surveillance. An analysis of genetic structure was conducted among populations of A. aegypti from 11 localities in four demographic regions within six Brazilian federal states. Markers included 21 random amplified polymorphic DNA (RAPD) loci. RAPD markers were detected among populations and cluster analysis revealed two main groups. We found high genetic polymorphism (H S = 0.224) and high levels of genetic differentiation between populations from different states (G ST = 0.430), as well as in populations from cities in the same state (G ST = 0.410). These results indicate significant differentiation in A. aegypti populations in Brazil. Regression analyses of geographic distances and pairwise F ST values estimated from RAPD markers showed that there is a correlation between genetic structure and geographic localization.

Resumo em Inglês:

We investigated the expression of calcium-dependent phospholipid binding protein annexin-II (Ann-II) messenger RNA (mRNA) during preantral follicle development and in oocytes from antral follicles of different diameters (< 3 mm, 5 to 8 mm and > 8 mm). The action of retinol on Ann-II mRNA expression in mature oocytes was also examined. Only oocytes from secondary preantral follicles expressed Ann-II mRNA and at the germinal vesicle stage expression by oocytes from follicles larger than 8 mm was significantly higher (p < 0.05) compared with oocytes from follicles smaller than 3 mm or between 5 and 8 mm. Ann-II mRNA expression by metaphase II oocytes from follicles larger than 8 mm was significantly higher (p < 0.05) than that from oocytes from follicles smaller than 3 mm, with oocytes from both these size-classes showing similar levels of Ann-II mRNA expression as oocytes recovered from 5-8 mm follicles. In the presence of retinol, Ann-II mRNA expression was higher than when retinol was absent (p < 0.05). Our data indicate that Ann-II mRNA expression is highest in competent oocytes and that retinol increases Ann-II mRNA and may be involved in the regulation of oocyte competence by decreasing the translation and/or degradation of Ann-II mRNA.

Resumo em Inglês:

Activation tagging is a powerful tool to identify new mutants and to obtain information about possible biological functions of the overexpressed genes. The quadruple cauliflower mosaic virus (CaMV) 35S enhancer fragment is a strong enhancer, which is most commonly used for this purpose. However, the constitutive nature of this enhancer may generate lethal mutations or aberrations in different plant organs by the same overexpressed gene. A tissue-specific activation tagging approach may overcome these drawbacks and may also lead more efficiently to the desired phenotype. For this reason the SHATTERPROOF2 (SHP2) promoter fragment was analysed for enhancer activity. The SHP2 gene is involved in dehiscence zone development and expressed during silique development. The aim of the experiments described here was to identify a dehiscence zone specific enhancer that could be used for tissue-specific activation tagging. The chosen SHP2 enhancer fragment was found to be expressed predominantly in the dehiscence zone and showed enhancer activity as well as ectopic expression activity. This activity was not influenced by its orientation towards the promoter and it was still functional at the largest tested distance of 2.0 kb. Based on these results, the SHP2 enhancer fragment can potentially be used in a tissue-specific activation tagging approach to identify new Arabidopsis mutants with an altered dehiscence zone formation.

Resumo em Inglês:

Protein-DNA interactions play a pivotal role in both the transcriptional control and the maintenance of genome integrity, and these are two properties that are closely linked to the development of an organism, differentiation, physiology and to the progression of diseases. Chemical and geometric properties are typically two of the key components in any analysis that aims to understand the precise origin of specificity and elucidate the atomic features of a protein-DNA interface. In this study, we have developed a unique representation of the directionality of the molecular surface of a DNA-binding protein. The stereo-orientation of the normal vector that signifies the geometric properties of a protein surface was projected onto a two-dimensional surface (referred to here as an earth map). We identified considerably diverse patterns of the vector distribution of the protein surface, and besides this, the DNA-contact surface, a subset of an entire protein surface, has also been found to contain diverse patterns. At the same time, the direction of the DNA-contact surface was also tracked onto the earth map on a base-pair basis and distinct intertwining properties particular to the specific family of that DNA-binding protein are revealed.