Scielo RSS <![CDATA[Genetics and Molecular Biology]]> http://www.scielo.br/rss.php?pid=1415-475720080001&lang=en vol. 31 num. 1 lang. en <![CDATA[SciELO Logo]]> http://www.scielo.br/img/en/fbpelogp.gif http://www.scielo.br <![CDATA[<B>A role for adeno-associated viral vectors in gene therapy</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100001&lng=en&nrm=iso&tlng=en Gene therapy constitutes a therapeutic intervention based on modification of the genetic material of living cells, by correcting genetic defects or overexpressing therapeutic proteins. The success of gene therapy protocols depends on the availability of therapeutically suitable genes, appropriate gene delivery systems and proof of safety and efficacy. Recent advances on the development of gene delivery systems, particularly on viral vectors engineering and improved gene regulatory systems, have led to marked progress in this field. Although the available vector systems can successfully transfer genes into cells, the ideal delivery vehicle has not been found. In this context, adeno-associated virus vectors (AAV) are arising as a promising tool for a wide range of applications, due to a combination of characteristics such as lack of pathogenicity and immunogenicity, wide range of cell tropism and long-term gene expression. Since its isolation, the biological properties of the adeno-associated virus have been increasingly understood, improving our ability to manipulate and use it as a safe and efficient gene therapy vector of wide spectrum. In this work, we review the bases of gene therapy, main types of gene transfer systems and basic properties and use of AAV vectors. <![CDATA[<B>Mitochondrial DNA mapping of social-biological interactions in Brazilian Amazonian African-descendant populations</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100002&lng=en&nrm=iso&tlng=en The formation of the Brazilian Amazonian population has historically involved three main ethnic groups, Amerindian, African and European. This has resulted in genetic investigations having been carried out using classical polymorphisms and molecular markers. To better understand the genetic variability and the micro-evolutionary processes acting in human groups in the Brazilian Amazon region we used mitochondrial DNA to investigate 159 maternally unrelated individuals from five Amazonian African-descendant communities. The mitochondrial lineage distribution indicated a contribution of 50.2% from Africans (L0, L1, L2, and L3), 46.6% from Amerindians (haplogroups A, B, C and D) and a small European contribution of 1.3%. These results indicated high genetic diversity in the Amerindian and African lineage groups, suggesting that the Brazilian Amazonian African-descendant populations reflect a possible population amalgamation of Amerindian women from different Amazonian indigenous tribes and African women from different geographic regions of Africa who had been brought to Brazil as slaves. The present study partially mapped the historical biological and social interactions that had occurred during the formation and expansion of Amazonian African-descendant communities. <![CDATA[<B>Mating and offspring frequencies under partial outcrossing in a structured population</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100003&lng=en&nrm=iso&tlng=en This paper gives a model of a structured population with respect to an autosomal locus with two alleles. The population reproduces in discrete and non-overlapping generations. The population is assumed to be in equilibrium in that exactly the same distribution of genotypic proportions is reproduced in each generation. The population is subdivided into 'localities' which are characterized by the local gene frequencies. Within each locality the genotypic proportions may depart from Hardy-Weinberg proportions and the same fixation index applies to all localities. The system departs from reality by assuming that the frequency of the first allele follows the beta distribution. However, this enables a convenient way to derive the mating frequencies of parents so that equilibrium is maintained. Wright's F-statistics are applied to characterize the population as a whole. The system is extended to permit an arbitrary level of outbreeding. <![CDATA[<B>Absence of the <I>-116A</I> variant of the butyrylcholinesterase <I>BCHE</I> gene in Guarani Amerindians from Mato Grosso do Sul</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100004&lng=en&nrm=iso&tlng=en Butyrylcholinesterase (BChE; EC 3.1.1.8; Online Mendelian Inheritance in Man (OMIM) number 177400) is an enzyme found in many human tissues and encoded by the BCHE gene, of which 65 variants have been identified. In a recent study we found that the -116A variant of exon 1 of the BCHE gene was associated with lower mean BChE activity. The present study analyzed the -116 single nucleotide polymorphism (SNP) in 253 Guarani Amerindian Brazilians from the state of Mato Grosso do Sul (148 Guarani-Kaiowá, 83 Guarani-Ñandeva and 22 Kaiowá-Ñandeva descendants) and verified that they were all homozygotic for the -116G variant. A comparative analysis of the -116 site in nine vertebrate species indicated the -116A variant as the ancestral type. This is the first study of the -116 SNP in Amerindians and it is therefore difficult to infer whether or not the -116A variant was always absent from southern paleo-Amerindians or was present and then subsequently lost due to evolutionary factors. <![CDATA[<B>Methylenetetrahydrofolate reductase polymorphisms in myeloid leukemia patients from Northeastern Brazil</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100005&lng=en&nrm=iso&tlng=en Methylenetetrahydrofolate reductase (MTHFR: EC 1.5.1.20) polymorphisms are associated to acute lymphoid leukemia in different populations. We used the polymerase chain reaction and the restriction fragment length polymorphism method (PCR-RFLP) to investigate MTHFR C677T and A1298C polymorphism frequencies in 67 patients with chronic myeloid leukemia (CML), 27 with acute myeloid leukemia FAB subtype M3 (AML-M3) and 100 apparently healthy controls. The MTHFR mutant allele frequencies were as follows: CML = 17.2% for C677T, 21.6% for A1298C; AML-M3 = 22.2% for C677T, 24.1% for A1298C; and controls = 20.5% for C677T, 21% for A1298C. Taken together, our results provide evidence that MTHFR polymorphisms have no influence on the development of CML or AML-M3. <![CDATA[<B>A novel c.197T <FONT FACE=Symbol>®</B></FONT> <B>A variant among Brazilian neonates with glucose-6-phosphate dehydrogenase deficiency</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100006&lng=en&nrm=iso&tlng=en Glucose-6-phosphate dehydrogenase (G6PD, EC 1.1.1.49) deficiency is the most common enzyme deficiency worldwide, causing a spectrum of diseases including neonatal hyperbilirubinemia and acute or chronic hemolysis. We used the methemoglobin reduction test and G6PD electrophoresis to screen 655 neonates (354 females and 301 males) for common G6PD mutations in the city of Salvador in the Northeastern Brazilian state Bahia and found that 66 (10.1%) were G6PD-deficient (41 females and 25 males). The 66 (10.1%) G6PD-deficient neonates were assessed for the c.376 A -> G (exon 5) and c.202 G -> A (exon 4) mutations using the polymerase chain reaction and restriction enzyme fragment length polymorphism (PCR-RFLP) analysis and the results validated by DNA sequencing. Of the 66 G6PD-deficient neonates investigated we found that 54 (81.8%) presented the c.376 A -> G (p.Asn126Asp) and c.202 G -> A (p.Val68Met) mutations, two (3%) had the c.376 A -> G mutation only, two (3%) had the c.202 G -> A mutation only, five (7.6%) exhibited a previously unrecorded 197T -> A (p.Phe66Thr) substitution in exon 4 and three showed no mutations at any of these sites. Of the five neonates exhibiting the new 197T -> A (p.Phe66Thr) substitution, four (6.1%) also presented the c.202 G -> A and c.376 A -> G mutations and one (1.5%) had the c.[197T -> A / 202 G -> A] combination. We propose to name the new variant G6PD Bahia. <![CDATA[<B>Myeloproliferative syndrome of monosomy 7</B>: <B>a brief report</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100007&lng=en&nrm=iso&tlng=en We report the case of a five-month-old black male infant who had recurrent episodes of respiratory infections and also presented anemia and enlargements of the spleen, liver and lymphnodes. Hematological analysis revealed morphological abnormalities with megaloblastic dyserythropoiesis, while fetal hemoglobin assaying showed normal levels. Conventional and molecular cytogenetic analysis revealed monosomy of chromosome 7. Despite all therapeutic efforts during allogenic bone marrow transplantation, the child died due to generalized infection. The clinical and genetic distinctions between monosomy 7 syndrome and myelodysplastic disorders in childhood are discussed. <![CDATA[<B>Polymorphisms in the <I>glutathione S-transferase theta</I> and <I>mu</I> genes and susceptibility to myeloid leukemia in Brazilian patients</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100008&lng=en&nrm=iso&tlng=en The null genotype for glutathione S-transferase (GST, EC 2.5.1.18) gene polymorphisms is considered a risk factor for leukemia in different populations. In this work we investigated the GSTT1 and GSTM1 polymorphisms using multiplex PCR in 53 patients with chronic myeloid leukemia (CML), 23 with acute promyelocytic leukemia (APL) and 304 apparently healthy controls. In this association study we found that the GSTT1null genotype was more frequent in our group of APL patients than in the control group [OR = 2.75 (95% CI = 1.10-6.88)], providing evidence that a deletion in the GSTT1 gene could be a risk factor for this type of leukemia. <![CDATA[<B>Chromosome polymorphisms in natural populations of the South American grasshopper <I>Sinipta dalmani</B></I>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100009&lng=en&nrm=iso&tlng=en Six populations of Sinipta dalmani from the provinces of Buenos Aires and Entre Rios (Argentina) were analyzed. The populations of "El Palmar" National Park (Entre Rios) were polymorphic for pericentric inversions in pairs M4 and M7 and for a centric fusion involving pair M5 and the X chromosome. The M4 inversion remained similar over time and the karyomorphic frequencies did not depart from those expected according to the Hardy-Weinberg equilibrium. The analysis of chiasma frequency and distribution showed clear intra- and interchromosome effects of the different chromosome rearrangements. Both inversions and centric fusions were related with total or partial crossing over restriction in heterozygous condition, leading to a genetic differentiation between rearranged and non-rearranged chromosomes. The chromosome polymorphisms analyzed herein were associated with an increase in the number of terminal chiasmata both in the rearranged chromosomes (heterozygous centric fusion and homozygous M4 inversion) and in the other chromosomes (M4 inversion). Our results showed that the chromosome polymorphisms in S. dalmani may be associated with a significant decrease in genetic recombination, which may explain in part their maintenance in some areas of its geographical distribution. <![CDATA[<B>Cytogenetic characterization of <I>Melipona rufiventris</I> Lepeletier 1836 and <I>Melipona mondury</I> Smith 1863 (Hymenoptera, Apidae) by C banding and fluorochromes staining</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100010&lng=en&nrm=iso&tlng=en The stingless bees Melipona rufiventris and M. mondury were analyzed cytogenetically by conventional staining with Giemsa, C-banding and sequential staining with the fluorochromes CMA3/DA/DAPI. Both species presented 2n = 18 and n = 9, except for one colony of M. rufiventris, in which some individuals had 2n = 19 due to the presence of a B chromosome. After Giemsa staining and C-banding the chromosomes appeared very condensed and presented a high heterochromatic content, making it difficult to localize the centromere and therefore to visualize the chromosomes morphology. The constitutive heterochromatin was located in interstitial chromosome regions covering most of the chromosomes extension and consisted mainly of AT, as shown by DAPI staining. The euchromatin was restricted to the chromosome extremities and was GC-rich, as evidenced by CMA3 staining. The B chromosome was CMA3-negative and DAPI-positive, a heterochromatic constitution similar to that of the A genome chromosomes. <![CDATA[<B>Chromosome polymorphism in the Brazilian dwarf brocket deer, <I>Mazama nana</I> (Mammalia, Cervidae)</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100011&lng=en&nrm=iso&tlng=en The Brazilian dwarf brocket deer (Mazama nana) is the smallest deer species in Brazil and is considered threatened due to the reduction and alteration of its habitat, the Atlantic Rainforest. Moreover, previous work suggested the presence of intraspecific chromosome polymorphisms which may contribute to further population instability because of the reduced fertility arising from the deleterious effects of chromosome rearrangements during meiosis. We used G- and C-banding, and nucleolus organizer regions localization by silver-nitrate staining (Ag-NOR) to investigate the causes of this variation. Mazama nana exhibited eight different karyotypes (2n = 36 through 39 and FN = 58) resulting from centric fusions and from inter and intraindividual variation in the number of B chromosomes (one to six). Most of the animals were heterozygous for a single fusion, suggesting one or several of the following: a) genetic instability in a species that has not reached its optimal karyotypic evolutionary state yet; b) negative selective pressure acting on accumulated rearrangements; and c) probable positive selection pressure for heterozygous individuals which maintains the polymorphism in the population (in contrast with the negative selection for many rearrangements within a single individual). <![CDATA[<B>PCR-mediated recombination in development of microsatellite markers</B>: <B>mechanism and implications</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100012&lng=en&nrm=iso&tlng=en Protocols for microsatellite-enrichment libraries have been widely applied to several species in order to supply the most informative molecular markers for population and inbreeding studies. One drawback of these protocols is the ratio of designed primer pairs that fail to amplify the expected fragment, even after exhaustive optimization attempts. A possible cause of unsuccessful microsatellite primers may be that such loci are artifacts resulting from chimeric PCR products, instead of real genomic sequences. The microsatellite-enriched library constructed for Aegla longirostri (Crustacea, Decapoda, Anomura) showed that 29% of sequenced clones were chimeric products because these sequences shared one of the flanking regions around the same repeat motif but not the other. PCR-mediated recombination is a well-known event described for several procedures in which related sequences are used as a template. We have associated this phenomenon with microsatellite marker development. This study explained the high ratio of recombinant sequences generated in the A. longirostri microsatellite-enriched library. We discuss the mechanism and implications of PCR chimeric-product formation during microsatellite isolation. <![CDATA[<B>DNA testing for parentage verification in a conservation nucleus of Pantaneiro horse</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100013&lng=en&nrm=iso&tlng=en We investigated the genealogy of the in situ conservation nucleus of the Pantaneiro horse using DNA microsatellites by evaluating 101 horses, the group consisting of 71 adult horses (3 stallions, 40 male and 31 mares) and 27 foals (14 colts and 13 fillies). Genomic DNA was extracted from hair roots and genotyped using 12 microsatellite markers (AHT4, AHT5, ASB2, ASB17, ASB23, HMS3 HMS6, HMS7, HTG4, HTG10, LEX33 and VHL20). The number of alleles per locus varied from 6 to 13, with a mean of 7.8 and the expected heterozygosity ranged from 0.544 to 0.734 (mean 0.644). The VLH20, ASB2, HTG10, ASB23 markers had a high (> 0.8) polymorphism information content and the total exclusion probability of the 12 microsatellite loci was 0.99. The genealogical study of the Pantaneiro horse using genetic markers was efficient in detecting mistakes during paternity and maternity designation and is an important tool which can be used together with traditional systems of animal identification. The use of genetic markers is recommended in the systematic control of the genealogical registrations and conservation plans to improve genetic aspects of the Pantaneiro horse. <![CDATA[<B>Genetic variability and efficiency of DNA microsatellite markers for paternity testing in horse breeds from the Brazilian Marajó archipelago</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100014&lng=en&nrm=iso&tlng=en In this study, 15 microsatellite DNA loci used in comparative tests by the International Society for Animal Genetics were applied to the evaluation of genetic diversity and management, and the efficiency of paternity testing in Marajoara horses and Puruca ponies from the Marajó Archipelago. Based on the genotyping of 93 animals, mean allelic diversity was estimated as 9.14 and 7.00 for the Marajoara and Puruca breeds, respectively. While these values are similar to those recorded in most European breeds, mean levels of heterozygosity were much lower (Marajoara 49%, Puruca 40%), probably as a result of high levels of inbreeding in the Marajó populations. The mean informative polymorphic content of this 15-marker system was over 50% in both breeds, and was slightly higher in the Marajoara horses. The discriminative power and exclusion probabilities derived from this system were over 99% for both populations, emphasizing the efficacy of these markers for paternity testing and genetic management in the two breeds. <![CDATA[<B>Inclusion of genetic relationship information in the pedigree selection method using mixed models</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100015&lng=en&nrm=iso&tlng=en We used a mixed model approach and computer simulation to evaluate the inclusion of parentage information as determined by the genealogy established in the pedigree method. The simulations were based on a purely additive genetic model for one quantitative trait of 20 unlinked segregating loci with equal effects and an allelic frequency of 0.5 for heritability values of 10%, 25%, 50% and 75% for selection based on an F4:5 progeny mean. We simulated 1000 experiments for each heritability value, corresponding to the evaluation of 256 F4:5 progenies. The phenotypic values of the progenies were analyzed according to two models, one ignoring and one considering the additive genetic parentage among the progenies. The additive relationship coefficients among F4:5 progenies ranged from 0.0 to 1.75. The evaluated selection procedures were the phenotypic progeny mean (M) and the best linear unbiased predictor including parentage (BLUP A). The inclusion of parentage among progenies using the BLUP A procedure resulted in higher selection gains than when the relationship information was ignored, which possibly recompenses the additional work invested to obtain these records, above all in the case of low - heritability traits. <![CDATA[<B>Genetic diversity in section <I>Rhizomatosae</I> of the genus <I>Arachis</I> (Fabaceae) based on microsatellite markers </B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100016&lng=en&nrm=iso&tlng=en The genus Arachis (Fabaceae) native to South America, contains 80 species divided into nine sections, three of which contain species of special economic importance such as the cultivated peanut (Arachis hypogaea), belonging to the section Arachis, and some perennial forage species from sections Caulorrhizae and Rhizomatosae. We used microsatellite markers to assay genetic variability among 77 accessions of four species from section Rhizomatosae, the diploid Arachis burkartii (2n = 2x = 20) and the tetraploid Arachis glabrata, Arachis pseudovillosa and Arachis nitida (2n = 4x = 40). A total of 249 alleles were found in the fifteen loci analyzed and a high degree of intra and interspecific polymorphism was detected. The lowest intraspecific variation occurred in Arachis burkartii, while the smallest estimated interspecific value was between A. nitida and A. pseudovillosa and the largest was between A. burkartii and A. nitida. High observed heterozygosity was detected in A. glabrata. The diploid accessions grouped in one cluster and the tetraploid accessions in another. It was possible to distinguish all 77 accessions and the genetic distance between accessions could not be correlated with geographic origin. <![CDATA[<B>Genetic effects for maize traits in acid and non-acid soils</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100017&lng=en&nrm=iso&tlng=en Breeding programs for acid-soil tolerance are desirable as a relatively inexpensive and permanent way for increasing maize (Zea mays L.) yield on these soils. Our objective was to compare the genetic effects controlling the expression of maize traits in acid and non-acid soils. Seven related and one unrelated inbred lines, with different levels of tolerance to acid soil, and their F1, F2, BC1, and BC2 generations were evaluated in four acid and two non-acid soils. Estimates of additive, dominance, and epistatic effects were computed for grain yield, plant height, days to mid-silk, and prolificacy, using the generation means analysis procedure. For all traits the major part of the variation was accounted for by additive and dominance effects, with dominance effects being more important than additive and epistatic effects for both acid and non-acid soils. Epistatic effects were significant for some crosses only, being more pronounced for plant height than for the other traits. Furthermore, epistatic effects were randomly distributed among the crosses and were not related to the grain yield of the single-crosses (F1's) and to the genetic relationships of the inbreds in either type of soil. The results suggest that similar pooled gene effects control the expression of the traits assessed in both acid and non-acid soils. <![CDATA[<B>Genetic control of soybean (<I>Glycine max</I>) yield in the absence and presence of the Asian rust fungus (<I>Phakopsora pachyrhizi</I>)</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100018&lng=en&nrm=iso&tlng=en Soybean is one of the most important crops in Brazil and continuously generates demands for production technologies, such as cultivars resistant to diseases. In recent years, the Asian rust fungus (Phakopsora pachyrhizi Syd. & P. Syd 1914) has caused severe yield losses and the development of resistant cultivars is the best means of control. Understanding the genetic control and estimating parameters associated with soybean (Glycine max) resistance to P. pachyrhizi will provide essential information for cultivar selection. We investigated quantitative genetic control of P. pachyrhizi and estimated parameters associated to soybean yield in the absence and presence of this phytopathogen. Six cultivars and their 15 diallel derived F2 and F3 generations were assessed in experiments carried out in the absence and presence of P. pachyrhizi. The results indicated that soybean yield in the presence and absence of P. pachyrhizi is controlled by polygenes expressing predominantly additive effects that can be selected to develop new cultivars resistant or tolerant to P. pachyrhizi. These cultivars may prove to be a useful and more durable alternative than cultivars carrying major resistance genes. <![CDATA[<B>BOX-PCR-based identification of bacterial species belonging to <I>Pseudomonas syringae</B></I>: <B><I>P</I>. <I>viridiflava</I> group</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100019&lng=en&nrm=iso&tlng=en The phenotypic characteristics and genetic fingerprints of a collection of 120 bacterial strains, belonging to Pseudomonas syringae sensu lato group, P. viridiflava and reference bacteria were evaluated, with the aim of species identification. The numerical analysis of 119 nutritional characteristics did not show patterns that would help with identification. Regarding the genetic fingerprinting, the results of the present study supported the observation that BOX-PCR seems to be able to identify bacterial strains at species level. After numerical analyses of the bar-codes, all pathovars belonging to each one of the nine described genomospecies were clustered together at a distance of 0.72, and could be separated at genomic species level. Two P. syringae strains of unknown pathovars (CFBP 3650 and CFBP 3662) and the three P. syringae pv. actinidiae strains were grouped in two extra clusters and might eventually constitute two new species. This genomic species clustering was particularly evident for genomospecies 4, which gathered P. syringae pvs. atropurpurea, coronafaciens, garçae, oryzae, porri, striafaciens, and zizaniae at a noticeably low distance. <![CDATA[<B>Sequence analysis of the rDNA intergenic spacer of <I>Metarhizium</I> strains isolated in Brazil </B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100020&lng=en&nrm=iso&tlng=en To assess the extent of genetic variability of rDNA intergenic spacer (IGS) in Metarhizium sp., 34 strains (27 isolated in Brazil) were sequenced and analyzed together with an additional 20 Metarhizium anisopliae var. anisopliae sequences retrieved from GenBank. Overall, the global nucleotide diversity for the region under study was of 0.090, while for the Brazilian isolates it was only 0.016. Phylogenetic analyses showed four well-supported groups (A, B, C, and D), one of which (D) has not been previously identified. All but one of the Brazilian strains cluster in this novel D phylogroup, suggesting that the genetic variation found in Brazil is a subset of the worldwide M. anisopiliae var. anisopliae variation. <![CDATA[<B>Cytotoxicity and genotoxicity of <I>Agaricus blazei</I> methanolic extract fractions assessed using gene and chromosomal mutation assays</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100021&lng=en&nrm=iso&tlng=en Functional food investigations have demonstrated the presence of substances that could be beneficial to human health when consumed. However, the toxic effects of some substances contained in foods have been determined. Reported medicinal and nutritive properties have led to the extensive commercialization of the basidiomycete fungi Agaricus blazei Murrill (sensu Heinemann), also known as Agaricus brasiliensis Wasser et al., Agaricus subrufescens Peck or the Brazilian medical mushroom (BMM). Different methanolic extract fractions (ME) of this mushroom were submitted to the cytokinesis-block micronucleus (CBMN) clastogenic assay and the hypoxanthine-guanine phosphoribosyl transferase locus (HGPRT) assay for gene mutation, both using Chinese hamster ovary cells clone K1 (CHO-K1). The results suggest that all the fractions tested possess cytotoxic and mutagenic potential but no clastogenic effects. Further information is needed on the biochemical components of the A. blazei methanol fractions to identify any substances with cytotoxic and/or mutagenicity potential. These findings indicate that A. blazei methanolic extract should not be used due to their genotoxicity and care should be taken in the use of A. blazei by the general population until further biochemical characterization of this fungi is completed. <![CDATA[<B>Over-activation of the <I>Drosophila melanogaster hsp83</I> gene by selenium intoxication </B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100022&lng=en&nrm=iso&tlng=en Selenium is an important dietary micronutrient and an essential component of selenoproteins and the active sites of some enzymes, although at high concentrations it is toxic. We investigated diphenyl diselenide ((C6H5)2Se2 ) for its effects on the developmental stages of Drosophila melanogaster and found that in the larval and pupae stages the toxic threshold for this compound when added to the banana-agar medium on which the larva were fed was 350 µmol. In adult flies, fed on the same media, there were no observable toxic effects below 500 µmol but there were toxic effects above 600 µmol, indicating that adult flies were more resistant to selenium intoxication. In larvae, a when diphenyl diselenide was present above the toxic threshold there was increased activation of the hsp83 heat shock protein gene. Selenium promotes oxidation of sulfhydryl groups and affects the folding of proteins and this could explain the over-expression of hsp83 because the product of this gene is involved in protein folding and defense responses, including the response to heat shock. <![CDATA[<B>An effective device for generating alginate microcapsules</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100023&lng=en&nrm=iso&tlng=en An alternative approach to somatic gene therapy is to deliver the therapeutic protein by implanting genetically modified cells that could overexpress the gene of interest. Microencapsulation devices were designed to protect cells from host rejection and prevent the foreign cells from spreading while allowing protein secretion. Alginate microcapsules form a semi-permeable structure that is suitable for in vivo injection. In this study, we report an effective laboratory protocol for producing calcium alginate microcapsules, following optimization of uniformly shaped and sized particles containing viable cells. Encapsulation of baby hamster kidney (BHK) cells in alginate microcapsules was performed using a simple device consisting of a cylinder of compressed air and a peristaltic pump. A cell suspension flow of 100 mL h-1 and an air jet flow of 10 L min-1 produced the best uniformity of microcapsule size and shape. Cells maintained viability in culture for 4 weeks without any signs of necrosis, and protein diffusion was observed during this period. Our results clearly demonstrated that microisolation of BHK cells in alginate using a simple assembly device could provide an environment that is capable of preserving live cells. In addition, encapsulated cells under the conditions described were able to secrete an active enzyme even after four weeks, thus becoming potentially compatible with therapeutic protein delivery. <![CDATA[<B>Mitodepressive and clastogenic effects of aqueous extracts of the lichens <I>Myelochroa lindmanii</I> and <I>Canoparmelia texana</I> (Lecanorales, Parmeliaceae) on meristematic cells in plant bioassays</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100024&lng=en&nrm=iso&tlng=en The cytotoxicity effect of aqueous extracts of the lichens species Myelochroa lindmanii and Canoparmelia texana (Lecanorales, Parmeliaceae) were evaluated using meristematic cells of lettuce (Lactuca sativa) and maize (Zea mays). The seasonal effect was also evaluated. Extracts of M. lindmanii and C. texana inhibited root growth and/or percentage germination, possibly due to alterations in the cell cycle. The M. lindmanii extract showed anti-mitotic effects and blocked the cell cycle in metaphase so that c-mitosis and cells with chromosome duplication were produced. The C. texana extract appeared to hinder cell division, increasing the number of interphase cells. In addition, both extracts caused an increase in percentage of cell death. Clastogenic effects were also observed, such as sticky chromosomes, bridges, fragments and later segregation. Both lichen species are thus potential sources of biologically active substances with possible applications in biology, medicine and agronomy. <![CDATA[<B>Genomic resources for the conservation and management of the harpy eagle (<I>Harpia harpyja</I>, Falconiformes, Accipitridae)</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100025&lng=en&nrm=iso&tlng=en We report the characterization and optimization of 45 heterologous microsatellite loci, and the development of a new set of molecular sex markers for the conservation and management of the Neotropical harpy eagle (Harpia harpyja L. 1758). Of the 45 microsatellites tested, 24 were polymorphic, six monomorphic, 10 uncharacterizable due to multiple bands and five did not amplify. The observed gene diversity of the analyzed sample of H. harpyja was low and similar to that of other threatened Falconiformes. While a high proportion of the microsatellite markers were highly variable, individuals of H. harpyja could be differentiated by a joint analysis of just three (p = 2.79 x 10-4) or four markers (p = 2.89 x 10-5). Paternity could be rejected with 95.23% and 97.83% probabilities using the same three and four markers, respectively. The sex determination markers easily and consistently differentiated males from females even with highly degraded DNA extracted from naturally shed feathers. The markers reported in this study potentially provide an excellent set of molecular tools for the conservation and management of wild and captive H. harpyja and they may also prove useful for the enigmatic Neotropical crested eagle (Morphnus guianensis Daudin 1800). <![CDATA[<B>Molecular characterization of SSS139, a new satellite DNA family in sibling species of the <I>Drosophila buzzatii</I> cluster</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100026&lng=en&nrm=iso&tlng=en We characterized sequences of a novel SSS139 RsaI satellite DNA family in Drosophila gouveai and Drosophila seriema, two members of the Drosophila buzzatii cluster (D. repleta group). The sequences were AT-rich (69%) with a monomer unit length of about 139 bp and contained two direct subrepeats of 14 bp and 16 bp, suggesting that it might have originated by the duplication of smaller sequences. Southern and dot-blot hybridization analyses also detected SSS139 in other Drosophila buzzatii cluster species (D. koepferae, D. antonietae, D. borborema and D. serido) but not in D. buzzatii. These results agree with the marginal phylogenetic position of D. buzzatii within the D. buzzatii cluster. <![CDATA[<B>Suitability of DNA extracted from archival specimens of fruit-eating bats of the genus <I>Artibeus</I> (Chiroptera, Phyllostomidae) for polymerase chain reaction and sequencing analysis</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100027&lng=en&nrm=iso&tlng=en To establish a technique which minimized the effects of fixation on the extraction of DNA from formalin-fixed tissues preserved in scientific collections we extracted DNA samples from fixed tissues using different methods and evaluated the effect of the different procedures on PCR and sequencing analysis. We investigated muscle and liver tissues from museum specimens of five species of fruit-eating (frugivorous) bats of the Neotropical genus Artibeus (Chiroptera, Phyllostomidae): A. fimbriatus, A. lituratus, A. jamaicensis, A. obscurus, and A. planirostris. The results indicated that treatment of tissues in buffered solutions at neutral pH and about 37 &deg;C for at least four days improves the quality and quantity of extracted DNA and the quality of the amplification and sequencing products. However, the comparison between the performance of DNA obtained from fixed and fresh tissues showed that, in spite of the fact that both types of tissue generate reliable sequences for use in phylogenetic analyses, DNA samples from fixed tissues presented a larger rate of errors in the different stages of the study. These results suggest that DNA extracted from formalin-fixed tissue can be used in molecular studies of Neotropical Artibeus bats and that our methodology may be applicable to other animal groups. <![CDATA[<B>Genetic structure in two northern muriqui populations (<I>Brachyteles hypoxanthus,</I> Primates, Atelidae) as inferred from fecal DNA</B>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100028&lng=en&nrm=iso&tlng=en We assessed the genetic diversity of two northern muriqui (Brachyteles hypoxanthus Primata, Atelidae) populations, the Feliciano Miguel Abdala population (FMA, n = 108) in the Brazilian state of Minas Gerais (19&deg;44' S, 41&deg;49' W) and the Santa Maria de Jetibá population (SMJ, n = 18) in the Brazilian state of Espírito Santo (20&deg;01' S, 40&deg;44' W). Fecal DNA was isolated and PCR-RFLP analysis used to analyze 2160 bp of mitochondrial DNA, made up of an 820 bp segment of the gene cytochrome c oxidase subunit 2 (cox2, EC 1.9.3.1), an 880 bp segment of the gene cytochrome b (cytb, EC 1.10.2.2) and 460 bp of the hypervariable segment of the mtDNA control region (HVRI). The cox2 and cytb sequences were monomorphic within and between populations whereas the HVRI revealed three different population exclusive haplotypes, one unique to the SMJ population and two, present at similar frequencies, in the FMA population. Overall haplotype diversity (h = 0.609) and nucleotide diversity (pi = 0.181) were high but reduced within populations. The populations were genetically structured with a high fixation index (F ST = 0.725), possibly due to historical subdivision. These findings have conservation implications because they seem to indicate that the populations are distinct management units.