Exercise training at MLSS decreases weight gain and increases aerobic capacity in obese Zucker rats.

This study aimed to identify the aerobic capacity enhancement and subsequent body weight (BW) status of obese Zucker rats (OZRs) after 4 weeks of treadmill running exercise at the maximal lactate steady state (MLSS). In addition to obese Zucker rats (OZRs), lean Wistar Kyoto rats (WKYs) were used, and both species were divided into control and exercise groups as follows: obese exercise (OZR-EX, n=5), obese control (OZR-CON, n=5), lean exercise (WKY-EX, n=5) and lean control (WKY-CON, n=5). The OZR and WKY exercise groups trained 5 days per week at 12.5 m.min-1 and 20 m.min-1, respectively. After 4 weeks of training, MLSS was ascertained to evaluate the animals' aerobic capacity using 3 different velocities (12.5, 15 and 17.5 m.min-1 for OZRs and 25, 30 and 35 m.min-1 for WKYs). The MLSS of OZR-EX was identified at the velocity of 15 m.min-1, representing a 20% increase in aerobic capacity after the exercise program. The MLSS of WKY-EX was identified at 30 m.min-1 with a 50% increase of in aerobic capacity. Obese animals that exercised showed reduced weight gain compared to the non-exercise obese control group (p <0.05). Our results thus show that exercise training at MLSS intensity increased the aerobic capacity in both obese and non-obese animals and also reduced BW gain.

Identification of a novel subtype of feline immunodeficiency virus in a population of naturally infected felines in the Brazilian Federal District.

The feline immunodeficiency virus (FIV) is a retrovirus that is found worldwide, and it can be assigned to six subtypes (A, B, C, D, E, and a putative subtype F) based on sequencing analysis of the env and gag genes. Subtypes A and B are the most common worldwide. In Brazil, several authors have isolated only subtype B, and its prevalence differs markedly among investigated populations. Blood samples from 200 domestic felines from the Federal District in Brazil were analyzed by PCR. Samples that tested positive for FIV were then cloned, sequenced, and analyzed phylogenetically and statistically. The results represent the first description of FIV infection in the Central Region of Brazil and suggest that only 2 % of felines in this region are positive for the virus. In addition, the analysis showed that one out of the four positive samples that we detected could not be assigned to any of the six classical subtypes. This sample was taken as a putative novel subtype of the FIV virus. The remaining three positive samples were assigned to subtype B, with differences existing among these samples.

Determination of the maximal lactate steady state in obese Zucker rats.

This study aims to identify the maximum lactate steady state (MLSS) in obese rats in order to provide a more effective tool in the exercise training prescription for this important animal model. To make such determination, obese (Zucker, n=5) (390.0±18.8 g) and lean (Wistar, n=5) (227.3±26.2 g) rats were studied. After adaptation of animals to treadmill, the MLSS was determined by using 3 different velocities (10 m.min⁻¹, 12.5 m.min⁻¹ and 15 m.min⁻¹ for Zucker and 15 m.min⁻¹, 20 m.min⁻¹ and 25 m.min⁻¹ for Wistar). The MLSS was defined as the highest blood lactate concentration that increased up to 1 mmol.L⁻¹ during constant exercise. In obese rats, the MLSS was found in a velocity considerably lower than in lean controls (12.5 m.min⁻¹ and 20 m.min⁻¹), respectively (p<0.05). Therefore, the identification of MLSS in obese Zucker rats is an important tool for exercise prescription and evaluation in obese rat models.

Genetic composition of a Brazilian population: the footprint of the Gold Cycle.

Ancestry-informative markers (AIMs) are powerful tools for inferring the genetic composition of admixed populations. In this study, we determined the genetic ancestry of the Ouro Preto (Brazil) population and evaluated the association between ancestry and self-reported skin color. The genetic ancestry of 189 children and adolescents was estimated by genotyping 15 AIMs. The estimate of population admixture was determined using the Bayesian Markov Chain Monte Carlo (MCMC) method implemented in two different programs (STRUCTURE and ADMIXMAP). Volunteers self-reported their skin colors. The European ancestry contribution ranged from 0.503 to 0.539, the African contribution ranged from 0.333 to 0.425, and the Amerindian component ranged from 0.04 to 0.164. The relative contributions of African (P < 0.016) and European (P < 0.011) ancestry differed significantly among skin color groups, except between black and dark-brown groups. The population of Ouro Preto has a higher contribution of African ancestry compared to the mean for the southeast region of Brazil. Therefore, extrapolating the African ancestry contribution for southeastern Brazil to the Ouro Preto population would underestimate the actual value for this city. We also showed that self-reported skin color could be appropriate for describing the genetic structure of this particular population.

ACE and ACTN3 genotypes in older women: muscular phenotypes.

This study examined the association between ACE I/D and ACTN3 R577X polymorphisms and muscle-related phenotypes and their adaptation to resistance training in older women. Volunteers (n=246;age=66.7 ± 5.5 years) underwent quadriceps strength assessment using isokinetics and fat-free mass by dual energy X-ray absorptiometry. 79 volunteers performed 24 weeks of resistance training and 75 were studied as controls. Genotypes were identified by standard procedures. No associations were observed for muscle strength for either gene, but volunteers carrying the D/D genotype presented higher appendicular fat-free mass compared to the I-allele carriers (6.3 ± 0.1 vs. 6.1 ± 0.1 kg/m (2)). The X-allele carriers presented higher relative fat-free mass when compared to homozygous R/R (16.3 ± 0.1 vs. 15.9 ± 0.1 kg/m (2)). All fat-free mass variables were significantly greater for carriers of both X/X and D/D genotypes. In response to RT, only the I-allele carriers significantly increased fat-free mass and a significant training × genotype interaction was noted. These findings do not support a pivotal role for the studied polymorphisms in determining muscle strength in older women, but suggest a modest role in fat-free mass determination. Of note, the results provide a novel insight that these genetic variations may interact to determine muscle mass in older women.

Iberian origin of Brazilian local pig breeds based on Cytochrome b (MT-CYB) sequence.

The aim of this work was to investigate the possible origin of local Brazilian pig breeds through Cytochrome b (MT-CYB) mitochondrial analyses. The results indicated that the main local pig breeds descended from two different European maternal lineages, both Iberian varieties. The haplotype relationship analysis showed that Monteiro, Nilo, Piau and Tatu breeds share haplotypes only with Iberian varieties, while the Moura breed presented a different maternal lineage. The Moura appears to share a high frequency of haplotypes with the Black Hairy Iberian variety and Hungarian Mangalica breed.

Development and use of single nucleotide polymorphism markers for candidate resistance genes in wild peanuts (Arachis spp).

The cultivated peanut (Arachis hypogaea L.) is an allotetraploid of recent origin, with an AABB genome and low genetic diversity. Perhaps because of its limited genetic diversity, this species lacks resistance to a number of important pests and diseases. In contrast, wild species of Arachis are genetically diverse and are rich sources of disease resistance genes. Consequently, a study of wild peanut relatives is attractive from two points of view: to help understand peanut genetics and to characterize wild alleles that could confer disease resistance. With this in mind, a diploid population from a cross between two wild peanut relatives was developed, in order to make a dense genetic map that could serve as a reference for peanut genetics and in order to characterize the regions of the Arachis genome that code for disease resistance. We tested two methods for developing and genotyping single nucleotide polymorphisms in candidate genes for disease resistance; one is based on single-base primer extension methods and the other is based on amplification refractory mutation system-polymerase chain reaction. We found single-base pair extension to be an efficient method, suitable for high-throughput, single-nucleotide polymorphism mapping; it allowed us to locate five candidate genes for resistance on our genetic map.

CD47 expression is decreased in hematopoietic progenitor cells in patients with myelofibrosis.

Myelofibrosis (MF) is characterized by increased circulating hematopoietic progenitor cells (HPCs), abnormal cytokine levels, and the survival advantage of neoplastic progenitors over their normal counterparts, which leads to progressive disappearance of polyclonal hematopoiesis. CD47 is a surface glycoprotein with many functions, such as acting as a phagocytosis inhibitor of the expressing cell, that is increased in normal hematopoietic stem and progenitor cells mobilized into the blood and several human cancer-initiating cells, such as in acute myeloid leukemia. We compared CD47 expression in hematopoietic stem and progenitor cells of patients with MF and controls and found it to be decreased in progenitors of MF. Exposure of control HPCs to the cytokines transforming growth factor ß and stromal-derived factor 1, which are important regulators of hematopoietic stem cell cycling and are overexpressed in patients with MF, did not modulate CD47 expression.

A multiplex single-base extension protocol for genotyping Cdx2, FokI, BsmI, ApaI, and TaqI polymorphisms of the vitamin D receptor gene.

The well-described role of the vitamin D endocrine system in bone metabolism makes its receptor a widely investigated candidate gene in association studies looking for the genetic basis of complex bone-related phenotypes. Most association studies genotype five polymorphic sites along the gene using PCR-RFLP and allele-specific amplification methods, which may not be the better choice in large case/control or cross-sectional studies. In this case, genotyping SNPs in parallel and using automated allele-calling methods are important to decrease genotyping errors due to manual data handling and save sample in cases where the amount of DNA is limited. The aim of this study was to present a straightforward method based on multiplex PCR amplification followed by multiplex single-base extension as a simple way to genotype five vitamin D receptor gene polymorphisms in parallel, which may be implemented in medium- to large-scale case/control or cross-sectional studies. The results regarding method feasibility and optimization are presented by genotyping eight paternity trios and seven samples of Brazilian postmenopausal women who took part in an ongoing association study carried out by members of our group.

Reduced circulating miR-196b levels is associated with preeclampsia.

MicroRNAs (miRs) are small noncoding RNAs, highly stable in plasma, that regulate gene expression by base-pairing to the 3'-untranslated region of target mRNAs. We compared the expression of 3 circulating miRs (miR-125b, miR-146a, and miR-196b), which is related to the control of cell proliferation, differentiation, and apoptosis in preeclamptic (n=19) and healthy pregnant women (n=14). We found that women with preeclampsia (PE) presented lower expression of miR-196b (-2.9-fold change). The other miRs were at similar levels. This study is the first to demonstrate this difference, and highlights new opportunities for investigation into the role of miRs in PE.

CD47 expression is decreased in hematopoietic progenitor cells in patients with myelofibrosis

Myelofibrosis (MF) is characterized by increased circulating hematopoietic progenitor cells (HPCs), abnormal cytokine levels, and the survival advantage of neoplastic progenitors over their normal counterparts, which leads to progressive disappearance of polyclonal hematopoiesis. CD47 is a surface glycoprotein with many functions, such as acting as a phagocytosis inhibitor of the expressing cell, that is increased in normal hematopoietic stem and progenitor cells mobilized into the blood and several human cancer-initiating cells, such as in acute myeloid leukemia. We compared CD47 expression in hematopoietic stem and progenitor cells of patients with MF and controls and found it to be decreased in progenitors of MF. Exposure of control HPCs to the cytokines transforming growth factor β and stromal-derived factor 1, which are important regulators of hematopoietic stem cell cycling and are overexpressed in patients with MF, did not modulate CD47 expression.

Exclusion of Class III malocclusion candidate loci in Brazilian families.

The role played by genetic components in the etiology of the Class III phenotype, a class of dental malocclusion, is not yet understood. Regions that may be related to the development of Class III malocclusion have been suggested previously. The aim of this study was to search for genetic linkage with 6 microsatellite markers (D1S234, D4S3038, D6S1689, D7S503, D10S1483, and D19S566), near previously proposed candidate regions for Class III. We performed a two-point parametric linkage analysis for 42 affected individuals from 10 Brazilian families with a positive Class III malocclusion segregation. Analysis of our data indicated that there was no evidence for linkage of any of the 6 microsatellite markers to a Class III locus at = zero, with data supporting exclusion for 5 of the 6 markers evaluated. The present work reinforces that Class III is likely to demonstrate locus heterogeneity, and there is a dependency of the genetic background of the population in linkage studies.

Physical activity, Cdx-2 genotype, and BMD.

The present study investigated the interaction between Cdx-2 polymorphism and physical activity level over bone mineral density (BMD) variation in Brazilian postmenopausal women. One hundred and ninety women volunteered to participate in the study (66.6 +/- 5.3 years, 64.58 +/- 11.74 kg and 151.94 +/- 6.36 cm). Physical activity level (PAL) was assessed using the international physical activity questionnaire (IPAQ). Lumbar spine (L2 - L4), femoral neck, great trochanter and Wards' triangle bone mineral density (BMD) were measured by dual-energy X-ray absorptiometry (DXA). The Cdx-2 polymorphism was genotyped by minisequencing, using the SNaPshottrade mark Multiplex System (Applied Biosystems, Foster City, CA, USA). Overall, no significant association was found between Cdx-2 polymorphism and adjusted BMD at any site. However, the results revealed a significant interaction between PAL and Cdx-2 genotype on adjusted femoral neck and Wards' triangle BMD. Active women carrying the Cdx-G/G genotype showed higher adjusted femoral neck and Wards' triangle BMD than inactive women carrying the same genotype, thus suggesting a larger chronic response to physical activity. These results suggest that, in postmenopausal women, the Cdx-2 polymorphism does not influence BMD by itself; however, it seems to affect the BMD response to physical activity since only the Cdx-G/G genotype carriers presented significant differences between active and inactive.

A multiplex single-base extension protocol for genotyping Cdx2, FokI, BsmI, ApaI, and TaqI polymorphisms of the vitamin D receptor gene

The well-described role of the vitamin D endocrine system in bone metabolism makes its receptor a widely investigated candidate gene in association studies looking for the genetic basis of complex bone-related phenotypes. Most association studies genotype five polymorphic sites along the gene using PCR-RFLP and allele-specific amplification methods, which may not be the better choice in large case/control or cross-sectional studies. In this case, genotyping SNPs in parallel and using automated allele-calling methods are important to decrease genotyping errors due to manual data handling and save sample in cases where the amount of DNA is limited. The aim of this study was to present a straightforward method based on multiplex PCR amplification followed by multiplex single-base extension as a simple way to genotype five vitamin D receptor gene polymorphisms in parallel, which may be implemented in medium- to large-scale case/control or cross-sectional studies. The results regarding method feasibility and optimization are presented by genotyping eight paternity trios and seven samples of Brazilian postmenopausal women who took part in an ongoing association study carried out by members of our group.

A novel polymorphic Alu insertion embedded in a LINE 1 retrotransposon in the human X chromosome (DXS225): identification and worldwide population study

We describe a novel polymorphic Alu insertion (DXS225) on the human X chromosome (Xq21.3) embedded into an L1 retrotransposon. The DXS225 polymorphism was genotyped in 684 males from the CEPH Human Genome Diversity Panel. This insertion was found in all regions of the globe, suggesting that it took place before modern humans spread from Africa ca. 100,000 years ago. However, only one Amerindian population (Karitiana) showed this insertion allele, which may have been introduced by European admixture. Thus, it appears likely that the Alu insertion was absent from pre-Columbian America. Analysis of molecular variance worldwide demonstrated that 92.2% of the genetic variance was concentrated within populations. DXS225 is flanked by two microsatellites (DXS8114 and DXS1002), which are 86 kb apart and are in very strong linkage disequilibrium. The combination of a unique event polymorphism on the X chromosome in linkage disequilibrium with two rapidly evolving microsatellites should provide a useful tool for studies of human evolution.