IFNG +874 T > A single nucleotide polymorphism is associated with leprosy among Brazilians

Leprosy is a chronic infectious disease caused by Mycobacterium leprae, a low virulence mycobacterium, and the outcome of disease is dependent on the host genetics for either susceptibility per se or severity. The IFNG gene codes for interferon-gamma (IFN-gamma), a cytokine that plays a key role in host defense against intracellular pathogens. Indeed, single nucleotide polymorphisms (SNPs) in IFNG have been evaluated in several genetic epidemiological studies, and the SNP +874T > A, the +874T allele, more specifically, has been associated with protection against infectious diseases, especially tuberculosis. Here, we evaluated the association of the IFNG locus with leprosy enrolling 2,125 Brazilian subjects. First, we conducted a case-control study with subjects recruited from the state of So Paulo, using the +874 T > A (rs2430561), +2109 A > G (rs1861494) and rs2069727 SNPs. Then, a second study including 1,370 individuals from Rio de Janeiro was conducted. Results of the case-control studies have shown a protective effect for +874T carriers (OR(adjusted) = 0.75; p = 0.005 for both studies combined), which was corroborated when these studies were compared with literature data. No association was found between the SNP +874T > A and the quantitative Mitsuda response. Nevertheless, the spontaneous IFN-gamma release by peripheral blood mononuclear cells was higher among +874T carriers. The results shown here along with a previously reported meta-analysis of tuberculosis studies indicate that the SNP +874T > A plays a role in resistance to mycobacterial diseases.

The 844ins68 cystathionine beta-synthase and C677T MTHFR gene polymorphism and the vaso-occlusive event risk in sickle cell disease

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ancestral polymorphism and recent invasion of transposable elements in Drosophila species

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

Effect of beta-lactoglobulin polymorphism and seasonality on bovine milk composition

The objective was to evaluate the effect of beta-lactoglobulin (beta-lg) polymorphism and seasonality on milk composition (fat, lactose, total solids, milk urea nitrogen, total protein, true protein, casein and somatic cell counts) of Holstein and Girolando cows. Milk and blood samples from 278 Holsteins cows and 156 Girolando cows were taken during two dry seasons and two rainy seasons, for milk composition analysis and to determine beta-lg genotypes, respectively. BB genotype was the most frequent for both breeds, followed by AA genotype for Holstein (BB>AA>AB) and by AB for Girolando cows (BB>AB>AA). No differences were found in milk compositional characteristics among genetic variants of beta-lg (AA, AB and BB) either between Holstein or Girolando cows. No association between milk composition and beta-lg genetic polymorphism was observed. During the dry season, independently of the breed considered, higher contents of lactose, true protein, casein and casein :true protein ratio were found.

Genetic variation between several species of sections Extranervosae, Caulorrhizae, Heteranthae, and Triseminatae (genus Arachis) estimated by DNA polymorphism

Genetic variation within and among accessions of the genus Arachis representing sections Extranervosae, Caulorrhizae, Heteranthae, and Triseminatae was evaluated using RFLP and RAPD markers. RAPD markers revealed a higher level of genetic diversity than did RFLP markers, both within and among the species evaluated. Phenograms based on various band-matching algorithms revealed three major clusters of similarity among the sections evaluated. The first group included the species from section Extranervosae, the second group consisted of sections Triseminatae, Caulorrhizae, and Heteranthae, and the third group consisted of one accession of Arachis hypogaea, which had been included as a representative of section Arachis. The phenograms obtained from the RAPD and RFLP data were similar but not identical. Arachis pietrarellii, assayed only by RAPD, showed a high degree of genetic similarity with Arachis villosulicarpa. This observation supported the hypothesis that these two species are closely related. It was also shown that accession V 7786, previously considered to be Arachis sp. aff. pietrarellii, and assayed using both RFLPs and RAPDs, was possibly a new species from section Extranervosae, but very distinct from A. pietrarellii.

Fluorescent amplified fragment length polymorphism (fAFLP) analyses and genetic diversity in Litopenaeus vannamei (Penaeidae)

The Pacific white shrimp, Litopenaeus vannamei (Penaeidae), represents about 95% of all Brazilian shrimp production. The Brazilian L. vannamei foundation broodstock was made up of specimens collected from different American Pacific sites, but little information was collected on the genetic structure of the broodstock. We used the fluorescence amplified fragment length polymorphism (fAFLP) method to study the genetic diversity of L. vannamei broodstock lines 03CMF1 and 03CBF1 originally produced by breeder-shrimps imported mainly from Panama and Ecuador, although wild individuals from other localities may also have been used in producing these two lines. Our results showed a total of 93 polymorphic bands ranging from 50 to 500 bp, the mean Nei's genetic diversity calculated for the total sample was 13.4% and identity and genetic distance analyses indicated high genetic homogeneity within and between both the broodstock lineages studied which suggests that they had similar genetic structure. These results may represent an important tool for the appropriate management of L. vannamei broodstocks. Copyright by the Brazilian Society of Genetics.

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.

β-casein gene polymorphism permits identification of bovine milk mixed with bubaline milk in mozzarella cheese

Mozzarella cheese is traditionally prepared from bubaline (Bubalus bubalis) milk, but product adulteration occurs mainly by addition of or full substitution by bovine milk. The aim of this study was to show the usefulnes of molecular markers to identify the admixture of bovine milk to bubaline milk during the manufacturing process of mozzarella cheese. Samples of mozzarella cheese were produced by adding seven different concentrations of bovine milk: 0%, 1%, 2%, 5%, 8%, 12% and 100%. DNA extracted from somatic cells found in cheese were submitted to PCR-RFLP analysis of casein genes: α-s1-CN - CSN1S1 that encompasses 954 bp from exon VII to intron IX (AluI and HinfI), β-CN - CSN2 including 495 bp of exon VII (Hae III and HinfI), and κ-CN - CSN3, encompassing 373 bp of exon IV (AluI and HindIII). Our results indicate that Hae III-RFLP of CSN2exon VII can be used as a molecular marker to detect the presence of bovine milk in mozzarella cheese. Copyright © 2008, Sociedade Brasileira de Genética.

Genetic polymorphism of Streptococcus mutans strains associated with incomplete caries removal

Aim: Despite the antibacterial properties of dental materials, the survival of residual bacteria under restorations has been demonstrated after incomplete caries removal. The aim of this study was to evaluate the genetic polymorphism of Streptococcus mutans strains isolated from deep dentinal lesions before and three months after incomplete caries removal. Methods: Samples of carious dentin were collected from 33 primary and/or permanent molars before and after indirect pulp treatment and processed for microbiological isolation of mutans streptococci (MS). After three months of the dental treatment, positive cultures for MS were detected in only ten of these teeth. DNA of MS isolates were obtained and subjected to polymerase chain reaction (PCR) for identification of S mutans. The arbitrary primed-PCR method (primer OPA-13) was used to detect the genetic polymorphism of S. mutans strains. Results: Identical or highly related S. mutans genotypes were observed in each tooth, regardless of the collect. Considering each tooth separately, a maximum of nine genotypic patterns were found in each tooth from all the collects. In addition, at least one genotypic pattern was repeated in the three collects. Genetic diversity was observed among the S. mutans isolates, obtained from different teeth after three months of the dental treatment. Conclusions: The persistence of identical genotypic patterns and the genetic similarity among the isolates, from the same tooth in distinct collects, showed the resistance of some S. mutans strains after incomplete caries removal treatment.

Color polymorphism in Leptodactylus fuscus (Anura, Leptodactylidae): A defensive strategy against predators?

Color patterns are strongly related to defensive strategies in anurans. Some anurans present more than one morphotype. Leptodactylus fuscus, for example, present two morphotypes (with and without vertebral white line). The proportion of each pattern in nature is different, whereby there are always more individuals without stripes. Therefore, we speculated if this difference in the observed color pattern is due to unequal predation pressures (i.e. stronger over the striped morphotype), and/or if there is a genetic component related to autossomic heritage. To test the selective predation over the morphotypes, we prepared plasticine models of L. fuscus with both phenotypes and placed them in the field. We did not find evidence of predation selection and as we found significant relationships between the proportions of the phenotypes and Mendelian proportions, we suggest that the phenotypes observed in this species are genetically determined (involving dominant and recessive alleles) and may not have a defensive function.

Hemoglobin polymorphism and hematological profile of Geoffroy's side-necked turtle (Phrynops geoffroanus, Testudines) in the northwestern region of São Paulo State, Brazil

Complete blood counts and hemoglobin isoform data were gathered from 36 specimens of the turtle species Phrynops geoffroanus from the northwestern region of São Paulo State, Brazil. They were collected in an urban area. The hemoglobin profiles were obtained after red blood cell lysis and by electrophoretic migration in alkaline pH, acid pH, and neutral pH buffer. The hemoglobin components were confirmed using high-performance liquid chromatography (HPLC). Erythrogram analysis included hematocrit, total hemoglobin concentration, total red blood cell count, and red blood cell indices. The leukogram included a total white blood cell count and a calculation of the percent values of neutrophils, lymphocytes, monocytes, basophils, eosinophils, heterophils, and azurophils. HPLC analysis revealed three hemoglobin components; the first with a concentration of 5.5%, the second was a major component with an average concentration of 67.1%, and the third with a concentration of 28.5%. The hematological profile obtained for these specimens allowed us to establish a pattern for P. geoffroanus in São Paulo State Northwestern region. The average hematocrit values were 22.5% for females and 24.0% for males. For total hemoglobin, we found average values of 6.66 g/dL in females and 7.22 g/dL in males. The number of white blood cells was 2725 x 103/μL for females and 2775 x 103/μL for males. There was a predominance of heterophils, eosinophils, and monocytes in both sexes. No significant differences were found between males and females for hematological profile. The hematological results were compared to literature data for other Chelonia. They were similar to what is known for fresh water turtles. © FUNPEC-RP.

Genetic polymorphism, molecular characterization and relatedness of Macrobrachium species (Palaemonidae) based on RAPD-PCR.

The prawn genus Macrobrachium belongs to the family Palaemonidae. Its species are widely distributed in lakes, reservoirs, floodplains, and rivers in tropical and subtropical regions of South America. Globally, the genus Macrobrachium includes nearly 210 known species, many of which have economic and ecological importance. We analyzed three species of this genus (M. jelskii, M. amazonicum and M. brasiliense) using RAPD-PCR to assess their genetic variability, genetic structure and the phylogenetic relationship between them and to look for molecular markers that enable separation of M. jelskii and M. amazonicum, which are closely related syntopic species. Ten different random decamer primers were used for DNA amplification, yielding 182 fragments. Three of these fragments were monomorphic and exclusive to M. amazonicum or M. jelskii and can be used as specific molecular markers to identify and separate these two species. Similarity indices and a phylogenetic tree showed that M. amazonicum and M. jelskii are closest to each other, while M. brasiliense was the most differentiated species among them; this may be attributed to the different habitat conditions to which these species have been submitted. This information will be useful for further studies on these important crustacean species.

DNA repair gene polymorphism is associated with the genetic basis of atherosclerotic coronary artery disease

Background: Atherosclerotic coronary artery disease (CAD) is a multifactorial process that appears to be caused by the interaction of environmental risk factors with multiple predisposing genes. It is nowadays accepted that increased levels of DNA damage induced by xenobiotics play an important role in the early phases of atherogenesis. Therefore, in this study, we focus on determining whether genetic variations in xenobiotic-metabolizing [glutathione-S-transferase theta 1 (GSTT1), glutathione-S-transferase mu 1 (GSTM1), cytochrome P450 IIEI (CYP2E1)] and DNA repair [X-ray cross-complementing group 1 (XRCC1)] genes might be associated with increased risk for CAD. Methods: A case-control study was conducted with 400 individuals who underwent subjected to coronary angiography. A total of 299 were patients diagnosed with effective coronary atherosclerosis (case group; >20% obstructive lesion), and 101 (control group) were individuals diagnosed as negative for CAD (<20% obstructive lesions). The polymorphism identifications for GSTM1 and GSTT1, and for CYP2E1 and XRCC1 genes were performed by polymerase chain reaction (PCR) amplification and by PCR-RFLP, respectively. Results and conclusions: The XRCC1 homozygous wild-type genotype Arg/Arg for codon 399 was statistically less pronounced in the case subjects (21.4%) than in controls (38.5%); individuals with the variant XRCC1 genotype had a 2.3-fold increased risk for coronary atherosclerosis than individuals with the wild-type genotype (OR=2.3, 95% CI=1.13-4.69). Conversely, no association between GSTM1, GSTT1, and CYP2E1gene polymorphisms and coronary atherosclerosis was detected. The results provide evidence of the role of DNA damage and repair in cardiovascular disease. © 2011 Elsevier Inc. All rights reserved.

Head and neck carcinogenesis: Impact of MTHFD1 G1958A polymorphism

Objective: To investigate the MTHFD1 G1958A polymorphism involved in the folate metabolism as a risk for head and neck cancer, and to find the association of the polymorphism with the risk factors and clinical and histopathological characteristics. Methods: Retrospective study investigating MTHFD1 G1958A polymorphism in 694 subjects (240 patients in the Case Group and 454 in the Control Group) by Restriction Fragment Length Polymorphism (RFLP) Analysis. Multiple logistic regression and chi-square tests were used in the statistical analysis. Results: Multivariable analysis showed that smoking and age over 42 years were disease predictors (p < 0.05). MTHFD1 1958GA or AA genotypes were associated with smoking (p = 0.04) and alcoholism (p = 0.03) and were more ofen found in more advanced stage tumors (p = 0.04) and in patients with a shorter survival (p = 0.03). Conclusion: Te presence of MTHFD1 G1948A polymorphism associated with smoking and alcoholism raises the head and neck cancer risk.