Ribosomal DNA ITS-1 intergenic spacer polymorphism in triatomines (Triatominae, Heteroptera)

The length polymorphism of ribosomal DNA ITS-1 intergenic spacer was analyzed in eight species of triatomines belonging to Triatoma, Rhodnius, and Panstrongylus genera. The analyzed species were Rhodnius domesticus, R. neivai, R. robustus, Triatoma brasiliensis, T. infestans, T. vitticeps, Panstrongylus megistus, and P. herreri. These insects are vectors of Chagas' disease, one of the most prominent public health problems among South American countries. This work allowed the differentiation between species of the Triatomini and Rhodniini tribes through the analysis of ITS-1 length polymorphism by PCR and RFLP techniques. The species of the Triatoma and Panstrongylus genera presented an amplified ITS-1 fragment between 600 and 1000 bp, whereas Rhodnius presented a less variable ITS-1 length fragment, around 300 bp, which could reflect the monophyletic origin of the Rhodniini tribe. Species belonging to this genus were further differentiated by RFLP with HaeIII and AluI endonucleases. Our results corroborate the hypothesis of polyphyletic origin in this group of insects and contribute to knowledge about evolutionary relationships in triatomines.

Polymorphism of the ITS-2 region of the ribosomal DNA of the Triatominae Rhodnius domesticus, R-pictipes, R-prolixus and R-stali

The polymerase chain reaction-restriction fragment length polymorphism technique (PCR-RFLP) was used to compare Rhodnius domesticus (Neiva & Pinto), R. pictipes (Stal), R. prolixus (Stal) and R. stali (Lent; Jurberg & Galvao) (Hemiptera: Reduviidae). The enzyme BstUI differentiated R. donzesticus, R. pictipes and R. prolixus, and HhaI differentiated R. domesticus, R. pictipes and R. stali. With the fingerprinting analysis generated by these two enzymes, it was possible to clearly identify all four species in the study.

Polymorphisms of DNA repair genes XRCC1 and XRCC3, interaction with environmental exposure and risk of chronic gastritis and gastric cancer

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A new biophysics approach using photoacoustic spectroscopy to study the DNA-ethidium bromide interaction

We have examined the binding processes of ethidium bromide interacting with calf thymus DNA using photoacoustic spectroscopy. These binding processes are generally investigated by a combination of absorption or fluorescence spectroscopies with hydrodynamic techniques. The employment of photoacoustic spectroscopy for the DNA-ethidium bromide system identified two binding manners for the dye. The presence of two isosbestic points (522 and 498 nm) during DNA titration was evidence of these binding modes. Analysis of the photoacoustic amplitude signal data was performed using the McGhee-von Hippel excluded site model. The binding constant obtained was 3.4 x 10(8) M(bp)(-1), and the number of base pairs excluded to another dye molecule by each bound dye molecule (n) was 2. A DNA drug dissociation process was applied using sodium dodecyl sulfate to elucidate the existence of a second and weaker binding mode. The dissociation constant determined was 0.43 mM, whose inverse value was less than the previously obtained binding constant, demonstrating the existence of the weaker binding mode. The calculated binding constant was adjusted by considering the dissociation constant and its new value was 1.2 x 10(9) M(bp)(-1) and the number of excluded sites was 2.6. Using the photoacoustic technique it is also possible to obtain results regarding the dependence of the quantum yield of the dye on its binding mode. While intercalated between two adjacent base pairs the quantum yield found was 0.87 and when associated with an external site it was 0.04. These results reinforce the presence of these two binding processes and show that photoacoustic spectroscopy is more extensive than commonly applied spectroscopies.

Genetic diversity of Stryphnodendron adstringens (Mart.) Coville determined by AFLP molecular markers

Bark extracts of Stryphnodendron adstringens (Mart) Coville a Leguminosae species, well known in Brazil as barbatimao, are popularly used as healing agent. The objective of this work was to determine the genetic diversity of S. adstringens populations and to correlate genetic distances to the production of tannins. S. adstringens accessions from populations found in Cerrado regions in the states of Goias, Minas Gerais and São Paulo were analyzed using the AFLP (Amplified Fragment Length Polymorphism) technique. A total of 236 polymorphic bands were scored and higher proportion of genetic diversity was found inter populations (70.9%), rather than intra populations (29.1%). F-ST value was found to be significantly greater than zero (0.2906), demonstrating the complex genetic structure of S. adstringens populations. Accessions collected in Cristalina, GO, showed higher percentage of polymorphic loci (87.3%) and the highest genetic diversity. The lowest genetic variability was detected among accessions from the population growing in Caldas Novas, GO. The genetic distance among populations was estimated using the Unweighted Pair Group Method with Arithmetic Mean (UPGMA), which grouped populations into 3 clusters. Moreover, chemotypes with tannin concentration above 40% showed higher genetic similarity. AFLP analysis proved to be an efficient gene mapping technique to determine the genetic diversity among remaining populations of S. adstringens. Obtained results may be employed to implement further strategies for the conservation of this medicinal plant. (C) 2011 Elsevier Ltd. All rights reserved.

Isolation and characterization of polymorphic microsatellites for the natural populations of barker frog Physalaemus cuvieri

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Isolation and characterization of 15 polymorphic microsatellites in the Plethodontid salamander Ensatina eschscholtzii

We developed 15 new polymorphic microsatellites for the plethodontid salamander Ensatina eschscholtzii. Loci were isolated from a genomic library from Ensatina eschscholtzii xanthoptica enriched for (AAAG)(n) repetitive elements. The number of alleles per locus ranged from 4 to 20 (mean 9) in the sampled population. Observed heterozygosity ranged from 0.37 to 1. None of the loci deviated from Hardy-Weinberg equilibrium or showed significant linkage disequilibrium after a Bonferroni correction for multiple comparisons. All loci amplified in the six other subspecies of the Ensatina eschscholtzii complex. These new markers will prove useful in measuring gene flow and population structure as well as patterns of mating and sperm use in Ensatina.

Impact of sewage sludge on the soil bacterial communities by DNA microarray analysis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Detection of Toxoplasma gondii DNA in the milk of naturally infected ewes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A new technique for thermal neutron detection using pyroelectric ceramics

In this article a new technique for thermal neutron detection using pyroelectric ceramics is described. The detector system is basically constituted of a PZT (lead zirconate titanate) ceramic attached to an uranium disk. The energy released in the uranium fission gives rise to an electrical signal in the detector which is amplified by a lock-in system. The neutron beam impinging on the uranium disk was modulated with a cadmium chopper. Thermal neutron fluxes within the interval of 103 to 106 n/cm2 s have been detected using a U3O8 pellet with 20% enrichment in 235U. © 1992.

Polymorphisms of DNA repair genes XRCC1 and XRCC3, interaction with environmental exposure and risk of chronic gastritis and grastic cancer

Aim: To evaluate the association between polymorphisms XRCC1 Arg194Trp and Arg399Gln and XRCC3 Thr241Met and the risk for chronic gastritis and gastric cancer, in a Southeastern Brazilian population. Methods: Genotyping by PCR-RFLP was carried out on 202 patients with chronic gastritis (CG) and 160 patients with gastric cancer (GC), matched to 202 (C1) and 150 (C2) controls, respectively. Results: No differences were observed among the studied groups with regard to the genotype distribution of XRCC1 codons 194 and 399 and of XRCC3 codon 241. However, the combined analyses of the three variant alleles (194Trp, 399Gln and 241Met) showed an increased risk for chronic gastritis when compared to the GC group. Moreover, an interaction between the polymorphic alleles and demographic and environmental factors was observed in the CG and GC groups. XRCC1 194Trp was associated with smoking in the CG group, while the variant alleles XRCC1 399Gln and XRCC3 241Met were related with gender, smoking, drinking and H pylori infection in the CG and GC groups. Conclusion: Our results showed no evidence of a rela-tionship between the polymorphisms XRCC1 Arg194Trp and Arg399Gln and XRCC3 Thr241Met and the risk of chronic gastritis and gastric cancer in the Brazilian population, but the combined effect of these variants may interact to increase the risk for chronic gastritis, considered a premalignant lesion. Our data also indicate a gene-environment interaction in the susceptibility to chronic gastritis and gastric cancer. © 2005 The WJG Press and Elsevier Inc. All rights reserved.

Toxoplasma gondii: Detection by mouse bioassay, histopathology, and polymerase chain reaction in tissues from experimentally infected pigs

In the present study, we evaluated three techniques, mouse bioassay, histopathology, and polymerase chain reaction (PCR) to detect Toxoplasma gondii infection in tissues from experimentally infected pigs. Twelve mixed breed pigs, seronegative for T. gondii using an indirect immunofluorescent antibody test (IFAT), were used. Ten pigs were infected with 4 × 104 VEG strain oocysts, and two were maintained as uninfected controls. Animals were killed 60 days pos infection. Muscle (heart, tongue, diaphragm, and masseter) and brain samples were collected to investigate the presence of T. gondii tissue cysts by the different assay methods. For the bioassay, samples of brain (50 g) and pool of muscle samples (12.5 g of tongue, masseter, diaphragm, and heart) were used. PCR was performed using Tox4 and Tox5 primers which amplified a 529 bp fragment. The DNA extraction and PCR were performed three times, and all tissue samples were tested individually (brain, tongue, masseter, diaphragm, and heart). For histopathology, fragments of tissues were fixed in 10% of buffered formal saline and stained with HE. Histopathological results were all negative. PCR showed 25/150 (16.6%) positive samples, being 17/120 (14.1%) and 8/30 (26.6%) from muscle, and brain tissues, respectively. Tissue cysts of T. gondii were identified by mouse bioassay in 54/98 (55.1%) samples, being 31/48 (64.6%) from muscle samples, and 23/50 (46.0%) from brain samples. Toxoplasma gondii isolation in muscle samples by mouse bioassay was higher than in PCR (P < 0.01). Results indicate that DNA from pig tissues interfered with 529-bp-PCR sensitivity, and mouse bioassay was better than PCR in detecting T. gondii in tissues from pigs. © 2006 Elsevier Inc. All rights reserved.

Genetic diversity in wild (Sus scrofa scrofa) and domestic (Sus scrofa domestica) pigs and their hybrids based on polymorphism of a fragment of the D-loop region in the mitochondrial DNA

We examined the variation in mitochondrial DNA by sequencing the D-loop region in wild and domestic (large-white breed) pigs, in hybrids between domestic and wild pigs, and in Monteiro pigs. A D-loop fragment of approximately 330 bp was amplified by PCR. Sequencing of DNA amplicons identified haplotypes previously described as European and Asian types. Monteiro pigs and wild pigs had European haplotypes and domestic pigs had both European and Asian haplotypes. ©FUNPEC-RP.

DNA damage and nitric oxide synthesis in experimentally infected Balb/c mice with Trypanosoma cruzi

This study aimed to evaluate whether experimental Chagas disease in acute phase under benznidazole therapy can cause DNA damage in peripheral blood, liver, heart, and spleen cells or induce nitric oxide synthesis in spleen cells. Twenty Balb/c mice were distributed into four groups: control (non-infected animals); Trypanosoma cruzi infected; T. cruzi infected and submitted to benznidazole therapy; and only treated with benznidazole. The results obtained with the single cell gel (comet) assay showed that T. cruzi was able induce DNA damage in heart cells of both benznidazole treated or untreated infected mice. Similarly, T. cruzi infected animals showed an increase of DNA lesions in spleen cells. Regarding nitric oxide synthesis, statistically significant differences (p < 0.05) were observed in all experimental groups compared to negative control, the strongest effect observed in the T. cruzi infected group. Taken together, these results indicate that T. cruzi may increase the level of DNA damage in mice heart and spleen cells. Probably, nitric oxide plays an important role in DNA damaging whereas benznidazole was able to minimize induced T. cruzi genotoxic effects in spleen cells. © 2006 Elsevier Inc. All rights reserved.