Population genetic analysis of large sequence polymorphisms in Plasmodium falciparum blood-stage antigens

Plasmodium falciparum, the causative agent of human malaria, invades host erythrocytes using several proteins on the surface of the invasive merozoite, which have been proposed as potential vaccine candidates. Members of the multi-gene PfRh family are surface antigens that have been shown to play a central role in directing merozoites to alternative erythrocyte receptors for invasion. Recently, we identified a large structural polymorphism, a 0.58 Kb deletion, in the C-terminal region of the PfRh2b gene, present at a high frequency in parasite populations from Senegal. We hypothesize that this region is a target of humoral immunity. Here, by analyzing 371 P. falciparum isolates we show that this major allele is present at varying frequencies in different populations within Senegal, Africa, and throughout the world. For allelic dimorphisms in the asexual stage antigens, Msp-2 and EBA-175, we find minimal geographic differentiation among parasite populations from Senegal and other African localities, suggesting extensive gene flow among these populations and/or immune-mediated frequency-dependent balancing selection. In contrast, we observe a higher level of inter-population divergence (as measured by F(st)) for the PfRh2b deletion, similar to that observed for SNPs from the sexual stage Pfs45/48 loci, which is postulated to be under directional selection. We confirm that the region containing the PfRh2b polymorphism is a target of humoral immune responses by demonstrating antibody reactivity of endemic sera. Our analysis of inter-population divergence suggests that in contrast to the large allelic dimorphisms in EBA-175 and Msp-2, the presence or absence of the large PfRh2b deletion may not elicit frequency-dependent immune selection, but may be under positive immune selection, having important implications for the development of these proteins as vaccine candidates. (C) 2009 Elsevier B.V. All rights reserved.

Limited global diversity of the Plasmodium vivax merozoite surface protein 4 gene

Merozoite surface proteins (MSPs) of the malaria parasites are major candidates for vaccine development targeting asexual blood stages. However, the diverse antigenic repertoire of these antigens that induce strain-specific protective immunity in human is a major challenge for vaccine design and often determines the efficacy of a vaccine. Here we further assessed the genetic diversity of Plasmodium vivax MSP4 (PvMSP4) protein using 195 parasite samples collected mostly from Thailand, Indonesia and Brazil. Overall, PvMSP4 is highly conserved with only eight amino acid substitutions. The majority of the haplotype diversity was restricted to the two short tetrapeptide repeat arrays in exon 1 and 2, respectively. Selection and neutrality tests indicated that exon 1 and the entire coding region of PvMSP4 were under purifying selection. Despite the limited nucleotide polymorphism of PvMSP4, significant genetic differentiation among the three major parasite populations was detected. Moreover, microgeographical heterogeneity was also evident in the parasite populations from different endemic areas of Thailand. (C) 2009 Elsevier B.V. All rights reserved.

Effects of aerobic exercise on the blood pressure, oxidative stress and eNOS gene polymorphism in pre-hypertensive older people

The polymorphisms of endothelial nitric oxide synthase (eNOS) are associated with reduced eNOS activity. Aerobic exercise training (AEX) may influence resting nitric oxide (NO) production, oxidative stress and blood pressure. The purpose of this study was to investigate the effect of AEX on the relationship among blood pressure, eNOS gene polymorphism and oxidative stress in pre-hypertensive older people. 118 pre-hypertensive subjects (59 +/- A 6 years) had blood samples collected after a 12 h overnight fast for assessing plasma NO metabolites (NOx) assays, thiobarbituric acid reactive substances (T-BARS) and superoxide dismutase activity (ecSOD). eNOS polymorphism (T-786C and G-894T) was done by standard PCR methods. All people were divided according to the genotype results (G1: TT/GG, G2: TT/GT + TT, G3: TC + CC/GG, G4: TC + CC/GT + TT). All parameters were measured before and after 6 months of AEX (70% of VO(2 max)). At baseline, no difference was found in systolic and diastolic blood pressure, ecSOD and T-BARS activity. Plasma NOx levels were significantly different between G1 (19 +/- A 1 mu M) and G4 (14.2 +/- A 0.6 mu M) and between G2 (20.1 +/- A 1.7 mu M) and G4 (14.2 +/- A 0.6 mu M). Therefore, reduced NOx concentration in G4 group occurred only when the polymorphisms were associated, suggesting that these results are more related to genetic factors than NO-scavenging effect. After AEX, the G4 increased NOx values (17.2 +/- A 1.2 mu M) and decreased blood pressure. G1, G3 and G4 decreased T-BARS levels. These results suggest the AEX can modulate the NOx concentration, eNOS activity and the relationship among eNOS gene polymorphism, oxidative stress and blood pressure especially in C (T-786C) and T (G-894T) allele carriers.

Protein variation in blood-dwelling schistosome worms generated by differential splicing of micro-exon gene transcripts

Schistosoma mansoni is a well-adapted blood-dwelling parasitic helminth, persisting for decades in its human host despite being continually exposed to potential immune attack. Here, we describe in detail micro-exon genes (MEG) in S. mansoni, some present in multiple copies, which represent a novel molecular system for creating protein variation through the alternate splicing of short (<= 36 bp) symmetric exons organized in tandem. Analysis of three closely related copies of one MEG family allowed us to trace several evolutionary events and propose a mechanism for micro-exon generation and diversification. Microarray experiments show that the majority of MEGs are up-regulated in life cycle stages associated with establishment in the mammalian host after skin penetration. Sequencing of RT-PCR products allowed the description of several alternate splice forms of micro-exon genes, highlighting the potential use of these transcripts to generate a complex pool of protein variants. We obtained direct evidence for the existence of such pools by proteomic analysis of secretions from migrating schistosomula and mature eggs. Whole-mount in situ hybridization and immunolocalization showed that MEG transcripts and proteins were restricted to glands or epithelia exposed to the external environment. The ability of schistosomes to produce a complex pool of variant proteins aligns them with the other major groups of blood parasites, but using a completely different mechanism. We believe that our data open a new chapter in the study of immune evasion by schistosomes, and their ability to generate variant proteins could represent a significant obstacle to vaccine development.

The effect of offering an energy and protein supplement to grazing canchim beef cows either postpartum or both pre- and postpartum on lipid blood metabolites and folliculogenesis

This study was designed to evaluate the effect of nutritional supplementation offered during the pre- and postpartum periods on serum cholesterol, triglycerides and total lipids of Canchim beef cows and their relationship with folliculogenesis. Thirty cows with predicted calving date between September and October, kept in pastures of Brachiaria brizantha cv. Marandu together with their calves, were randomly distributed into three experimental groups: the first received only a mineral mixture (Control Group, CG); the second group received a concentrate with 16% crude protein/kg dry matter (DM) and 3000 kcal digestible energy/kg DM offered for 45 days prepartum and 120 days postpartum (PREG); the third group received the concentrate from parturition until the 120th day postpartum (POSG). Consumption was estimated at 1% of body weight, and each cow received approximately 4.0 kg/day (fresh weight) of supplement. Blood samples were taken and an ultrasound examination of the ovaries was performed twice a week until the 60th day postpartum. The body condition score (BCS) and the weight of the cows were recorded at 15-day intervals from calving until the 60th day postpartum. Data are presented as mean +/- SEM. Mean weight and BCS at calving were, respectively, 448 +/- 54.9 kg and 6.2 +/- 0.25 (PREG); 432 +/- 71.1 kg and 5.5 +/- 0.69 (POSG); and 434 +/- 66.4 kg and 5.5 +/- 0.69 (CG). Total cholesterol (TC), triglycerides (TRIG) and total lipids (TLIP) were measured using colorimetry until the 60th day postpartum. TC averages were PREG 186 +/- 62.6 mg/dL, POSG 159 +/- 43.1 mg/dL and CG 133 +/- 35.1 mg/dL (P < 0.05). For TRIG, the means were PREG 29 +/- 11.3 mg/dL (P < 0.05), POSG 24 +/- 8.1 mg/dL and CG 26 +/- 12.1 mg/dL (P > 0.05). Serum concentrations of TLIP were PREG 588 +/- 145.6 mg/dL, POSG 512 +/- 137.6 mg/dL and CG 452 +/- 122.4 mg/dL (P < 0.05). The first dominant follicle (DF) was identified on Day 21 +/- 10.3 (PREG), 36 +/- 28.5 (POSG) and 51 +/- 32.8 (CG) after calving. The difference between PREG and CG was significant (P < 0.05). TC was positively correlated with the calving to first estrus interval (P < 0.05). Results showed that nutritional supplementation before parturition assured good body condition at calving and suggested that it was effective at increasing cholesterol availability to maintain ovarian follicle function and to favor earlier resumption of ovarian activity. (C) 2010 Published by Elsevier B.V.

Blood serum components and serum protein test of Hybro-PG broilers of different ages

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

The 434(G > C) polymorphism in the eosinophil cationic protein gene and its association with tissue eosinophilia in oral squamous cell carcinomas

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

Expression of renin-angiotensin system signalling compounds in maternal protein-restricted rats: effect on renal sodium excretion and blood pressure

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effects of aerobic exercise on the blood pressure, oxidative stress and eNOS gene polymorphism in pre-hypertensive older people

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

Effects of soy protein and resistance exercise on body composition and blood lipids in postmenopausal women

Objective: To assess the effect of soy protein and progressive resistance training on body composition and lipids in postmenopausal women.Design: In a controlled trial, 46 postmenopausal women were randomized to one of four groups: 25 g of soy protein (SP, n = 10), 25 g of soy protein plus resistance exercise (SPE, n = 14), 25 g of maltodextrine (placebo) (PL, n = 11), or placebo plus resistance exercise (PLE, n = 11). Progressive resistance training was held three times a week for 16 weeks and included 8 exercises (3 series of 8-12 repetitions). At baseline and after 16 weeks, body mass index, waist circumference (WC), body fat, muscle mass and serum lipid levels were measured. To confirm isoflavone absorption, urinary concentrations were determined. The t-test of Student and ANOVA were used in the statistical analysis.Results: Subjects were classified as overweight and showed android fat distribution: Urinary isoflavone excretion indicated compliance to soy protein treatment. After 16 weeks of intervention, both SPE and PLE groups showed a significant increase of 1.3 kg in muscle mass and reduction in WC of -1.4 and -2.1 cm, respectively (p < 0.05). Significant decreases in the mean values of total cholesterol and LDL (-29.0 and -24.0 mg/dL, p < 0.001 and p < 0.006, respectively) were observed in the users of soy protein alone (SP).Conclusions: Soy protein supplementation did not influence the indicators of body composition. However, it exerted possible favorable effects on lipid profile in postmenopausal women. The increase in muscle mass and reduction in abdominal fat were correlated with resistance training. (c) 2006 Elsevier B.V.. All rights reserved.

A new polymerase chain reaction/restriction fragment length polymorphism protocol for Plasmodium vivax circumsporozoite protein genotype (VK210, VK247, and P-vivax-like) determination

For the molecular diagnosis of Plasmodium vivax variants (VK210, VK247, and P. vivax-like) using DNA amplification procedures in the laboratory, the choice of rapid and inexpensive identification products of the 3 different genotypes is an important prerequisite. We report here the standardization of a new polymerase chain reaction/restriction fragment length polymorphism technique to identify the 3 described P. vivax circumsporozoite protein (CSP) variants using amplification of the central immunodominant region of the CSP gene of this protozoan. The simplicity, specificity, and sensitivity of the system described here is important to determine the prevalence and the distribution of infection with these P. vivax genotypes in endemic and nonendemic malaria areas, enabling a better understanding of their phylogeny. (c) 2007 Published by Elsevier B.V.