Protective effect of whey protein hydrolysates against hydrogen peroxide-induced oxidative stress on PC12 cells

The protective effect of whey protein hydrolysates (WPHs) against H₂O₂-induced oxidative damage on rat pheochromocytoma line 12 (PC12) cells was studied. Whey protein was hydrolyzed by pepsin and trypsin and purified by macrospore absorption resins. PC12 cells were pretreated with WPHs (from 369 to 1,980?Da) at different concentrations for 2?h, then washed and incubated with 100?μM H₂O₂ in the presence of WPHs for another 24?h. With 100–400?μg WPH/ml the viable cells increased by 20–30?% when incubated with H₂O₂ suggesting that they may play a role as antioxidant in foods.     

Evolutionary strata on the X chromosomes of the dioecious plant Silene latifolia: evidence from new sex-linked genes

Despite its recent evolutionary origin, the sex chromosome system of the plant Silene latifolia shows signs of progressive suppression of recombination having created evolutionary strata of different X-Y divergence on sex chromosomes. However, even after 8 years of effort, this result is based on analyses of five sex-linked gene sequences, and the maximum divergence (and thus the age of this plant's sex chromosome system) has remained uncertain. More genes are therefore needed. Here, by segregation analysis of intron size variants (ISVS) and single nucleotide polymorphisms (SNPs), we identify three new Y-linked genes, one being duplicated on the Y chromosome, and test for evolutionary strata. All the new genes have homologs on the X and Y chromosomes. Synonymous divergence estimated between the X and Y homolog pairs is within the range of those already reported. Genetic mapping of the new X-linked loci shows that the map is the same in all three families that have been studied so far and that X-Y divergence increases with genetic distance from the pseudoautosomal region. We can now conclude that the divergence value is saturated, confirming the cessation of X-Y recombination in the evolution of the sex chromosomes at approximately 10-20 MYA.     

Balancing selection and low recombination affect diversity near the self-incompatibility loci of the plant Arabidopsis lyrata

The self-incompatibility (S-) locus region of plants in the Brassica family is a small genome region. In Arabidopsis lyrata, the S-genes, SRK and SCR, encode the functional female and pollen recognition proteins, which must be coadapted to maintain correct associations between the two component genes, and thus self-incompatibility (SI). Recombinants would be self-compatible and thus probably disadvantageous in self-incompatible species. Therefore, tight linkage between the two genes in incompatibility systems is predicted to evolve to avoid producing such recombinant haplotypes. The evolution of low recombination in S-locus regions has not been rigorously tested. To test whether these regions' per-nucleotide recombination rates differ from those elsewhere in the genome, and to investigate whether the A. lyrata S-loci have the predicted effect on diversity in their immediate genome region, we studied diversity in genes that are linked to the S-loci but are not involved in incompatibility and are not under balancing selection. Compared with other A. lyrata loci, genes linked to the S-loci have extraordinarily high polymorphism. Our estimated recombination in this region, from fitting a model of the effects of S-allele polymorphism on linked neutral sites, supports the hypothesis of locally suppressed recombination around the S-locus.     

Phase 1/2a Trial of Plasmodium vivax Malaria Vaccine Candidate VMP001/AS01B in Malaria-Naive Adults: Safety,Immunogenicity, and Efficacy

Background

A vaccine to prevent infection and disease caused by Plasmodium vivax is needed both to reduce the morbidity caused by this parasite and as a key component in efforts to eradicate malaria worldwide. Vivax malaria protein 1 (VMP001), a novel chimeric protein that incorporates the amino- and carboxy- terminal regions of the circumsporozoite protein (CSP) and a truncated repeat region that contains repeat sequences from both the VK210 (type 1) and the VK247 (type 2) parasites, was developed as a vaccine candidate for global use.

Methods

We conducted a first-in-human Phase 1 dose escalation vaccine study with controlled human malaria infection (CHMI) of VMP001 formulated in the GSK Adjuvant System AS01_B. A total of 30 volunteers divided into 3 groups (10 per group) were given 3 intramuscular injections of 15μg, 30μg, or 60μg respectively of VMP001, all formulated in 500μL of AS01_B at each immunization. All vaccinated volunteers participated in a P. vivax CHMI 14 days following the third immunization. Six non-vaccinated subjects served as infectivity controls.

Results

The vaccine was shown to be well tolerated and immunogenic. All volunteers generated robust humoral and cellular immune responses to the vaccine antigen. Vaccination did not induce sterile protection; however, a small but significant delay in time to parasitemia was seen in 59% of vaccinated subjects compared to the control group. An association was identified between levels of anti-type 1 repeat antibodies and prepatent period.

Significance

This trial was the first to assess the efficacy of a P. vivax CSP vaccine candidate by CHMI. The association of type 1 repeat-specific antibody responses with delay in the prepatency period suggests that augmenting the immune responses to this domain may improve strain-specific vaccine efficacy. The availability of a P. vivax CHMI model will accelerate the process of P. vivax vaccine development, allowing better selection of candidate vaccines for advancement to field trials.     

Risk of Injection-Site Abscess among Infants Receiving a Preservative-Free,Two-Dose Vial Formulation of Pneumococcal Conjugate Vaccine in Kenya

There is a theoretical risk of adverse events following immunization with a preservative-free, 2-dose vial formulation of 10-valent-pneumococcal conjugate vaccine (PCV10). We set out to measure this risk. Four population-based surveillance sites in Kenya (total annual birth cohort of 11,500 infants) were used to conduct a 2-year post-introduction vaccine safety study of PCV10. Injection-site abscesses occurring within 7 days following vaccine administration were clinically diagnosed in all study sites (passive facility-based surveillance) and, also, detected by caregiver-reported symptoms of swelling plus discharge in two sites (active household-based surveillance). Abscess risk was expressed as the number of abscesses per 100,000 injections and was compared for the second vs first vial dose of PCV10 and for PCV10 vs pentavalent vaccine (comparator). A total of 58,288 PCV10 injections were recorded, including 24,054 and 19,702 identified as first and second vial doses, respectively (14,532 unknown vial dose). The risk ratio for abscess following injection with the second (41 per 100,000) vs first (33 per 100,000) vial dose of PCV10 was 1.22 (95% confidence interval [CI] 0.37–4.06). The comparator vaccine was changed from a 2-dose to 10-dose presentation midway through the study. The matched odds ratios for abscess following PCV10 were 1.00 (95% CI 0.12–8.56) and 0.27 (95% CI 0.14–0.54) when compared to the 2-dose and 10-dose pentavalent vaccine presentations, respectively. In Kenya immunization with PCV10 was not associated with an increased risk of injection site abscess, providing confidence that the vaccine may be safely used in Africa. The relatively higher risk of abscess following the 10-dose presentation of pentavalent vaccine merits further study.     

Dragon PolyA Spotter: predictor of poly(A) motifs within human genomic DNA sequences

MOTIVATION: Recognition of poly(A) signals in mRNA is relatively straightforward due to the presence of easily recognizable polyadenylic acid tail. However, the task of identifying poly(A) motifs in the primary genomic DNA sequence that correspond to poly(A) signals in mRNA is a far more challenging problem. Recognition of poly(A) signals is important for better gene annotation and understanding of the gene regulation mechanisms. In this work, we present one such poly(A) motif prediction method based on properties of human genomic DNA sequence surrounding a poly(A) motif. These properties include thermodynamic, physico-chemical and statistical characteristics. For predictions, we developed Artificial Neural Network and Random Forest models. These models are trained to recognize 12 most common poly(A) motifs in human DNA. Our predictors are available as a free web-based tool accessible at http://cbrc.kaust.edu.sa/dps. Compared with other reported predictors, our models achieve higher sensitivity and specificity and furthermore provide a consistent level of accuracy for 12 poly(A) motif variants. CONTACT: vladimir.bajic@kaust.edu.sa SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.     

SIRT4 inhibits glutamate dehydrogenase and opposes the effects of calorie restriction in pancreatic beta cells

Sir2 is an NAD-dependent deacetylase that connects metabolism with longevity in yeast, flies, and worms. Mammals have seven Sir2 homologs (SIRT1-7). We show that SIRT4 is a mitochondrial enzyme that uses NAD to ADP-ribosylate and downregulate glutamate dehydrogenase (GDH) activity. GDH is known to promote the metabolism of glutamate and glutamine, generating ATP, which promotes insulin secretion. Loss of SIRT4 in insulinoma cells activates GDH, thereby upregulating amino acid-stimulated insulin secretion. A similar effect is observed in pancreatic beta cells from mice deficient in SIRT4 or on the dietary regimen of calorie restriction (CR). Furthermore, GDH from SIRT4-deficient or CR mice is insensitive to phosphodiesterase, an enzyme that cleaves ADP-ribose, suggesting the absence of ADP-ribosylation. These results indicate that SIRT4 functions in beta cell mitochondria to repress the activity of GDH by ADP-ribosylation, thereby downregulating insulin secretion in response to amino acids, effects that are alleviated during CR.     

Use of Integrated Malaria Management Reduces Malaria in Kenya

Background

During an entomological survey in preparation for malaria control interventions in Mwea division, the number of malaria cases at the Kimbimbi sub-district hospital was in a steady decline. The underlying factors for this reduction were unknown and needed to be identified before any malaria intervention tools were deployed in the area. We therefore set out to investigate the potential factors that could have contributed to the decline of malaria cases in the hospital by analyzing the malaria control knowledge, attitudes and practices (KAP) that the residents in Mwea applied in an integrated fashion, also known as integrated malaria management (IMM).

Methods

Integrated Malaria Management was assessed among community members of Mwea division, central Kenya using KAP survey. The KAP study evaluated community members'' malaria disease management practices at the home and hospitals, personal protection measures used at the household level and malaria transmission prevention methods relating to vector control. Concurrently, we also passively examined the prevalence of malaria parasite infection via outpatient admission records at the major referral hospital in the area. In addition we studied the mosquito vector population dynamics, the malaria sporozoite infection status and entomological inoculation rates (EIR) over an 8 month period in 6 villages to determine the risk of malaria transmission in the entire division.

Results

A total of 389 households in Mwea division were interviewed in the KAP study while 90 houses were surveyed in the entomological study. Ninety eight percent of the households knew about malaria disease while approximately 70% of households knew its symptoms and methods to manage it. Ninety seven percent of the interviewed households went to a health center for malaria diagnosis and treatment. Similarly a higher proportion (81%) used anti-malarial medicines bought from local pharmacies. Almost 90% of households reported owning and using an insecticide treated bed net and 81% reported buying the nets within the last 5 years. The community also used mosquito reduction measures including, in order of preference, environmental management (35%), mosquito repellent and smoke (31%) insecticide canister sprays (11%), and window and door screens (6%). These methods used by the community comprise an integrated malaria management (IMM) package. Over the last 4 years prior to this study, the malaria cases in the community hospital reduced from about 40% in 2000 to less than 10% by 2004 and by the year 2007 malaria cases decreased to zero. In addition, a one time cross-sectional malaria parasite survey detected no Plasmodium infection in 300 primary school children in the area. Mosquito vector populations were variable in the six villages but were generally lower in villages that did not engage in irrigation activities. The malaria risk as estimated by EIR remained low and varied by village and proximity to irrigation areas. The average EIR in the area was estimated at 0.011 infectious bites per person per day.

Conclusions

The usage of a combination of malaria control tools in an integrated fashion by residents of Mwea division might have influenced the decreased malaria cases in the district hospital and in the school children. A vigorous campaign emphasizing IMM should be adopted and expanded in Mwea division and in other areas with different eco-epidemiological patterns of malaria transmission. With sustained implementation and support from community members integrated malaria management can reduce malaria significantly in affected communities in Africa.     

The Saccharomyces cerevisiae high mobility group box protein HMO1 contains two functional DNA binding domains

High mobility group box (HMGB) proteins are architectural proteins whose HMG DNA binding domains confer significant preference for distorted DNA, such as 4-way junctions. HMO1 is one of 10 Saccharomyces cerevisiae HMGB proteins, and it is required for normal growth and plasmid maintenance and for regulating the susceptibility of yeast chromatin to nuclease. Using electrophoretic mobility shift assays, we have shown here that HMO1 binds 26-bp duplex DNA with K(d) = 39.6 +/- 5.0 nm and that its divergent box A domain participates in DNA interactions, albeit with low affinity. HMO1 has only modest preference for DNA with altered conformations, including DNA with nicks, gaps, overhangs, or loops, as well as for 4-way junction structures and supercoiled DNA. HMO1 binds 4-way junctions with half-maximal saturation of 19.6 +/- 2.2 nm, with only a modest increase in affinity in the absence of magnesium ions (half-maximal saturation 6.1 +/- 1.1 nm). Whereas the box A domain contributes modest structure-specific binding, the box B domain is required for high affinity binding. HMO1 bends DNA, as measured by DNA cyclization assays, facilitating cyclization of 136-, 105-, and 87-bp DNA, but not 75-bp DNA, and it has a significantly longer residence time on DNA minicircles compared with linear duplex DNA. The unique DNA binding properties of HMO1 are consistent with global roles in the maintenance of chromatin structure.