Characterization of unique signature sequences in the divergent maternal protein Bcl2l10

Insertions or deletions (indels) of amino acids residues have been recognized as an important source of genetic and structural divergence between paralogous Bcl-2 family members. However, these signature sequences have not so far been extensively investigated amongst orthologous Bcl-2 family proteins. Bcl2l10 is an antiapoptotic member of the Bcl-2 family that has evolved rapidly throughout the vertebrate lineage and which shows conserved abundant expression in eggs and oocytes. In this paper, we have unraveled two major sites of divergence between human Bcl2l10 and its vertebrate homologs. The first one provides length variation at the N-terminus (before the BH4 domain) and the second one is located between the predicted α5-α6 pore-forming helices, providing an unprecedented case in the superfamily of helix-bundled pore-forming proteins. These two particular indels were studied phylogenetically and through biochemical and cell biological techniques, including truncation and site-directed mutagenesis. While deletion of the N-terminal extension had no significant functional impact in HeLa cells, our results suggest that the human Bcl2l10 protein evolved a calcium-binding motif in its α5-α6 interhelical region by acquiring critical negatively charged residues. Considering the reliance of female eggs on calcium-dependent proteins and calcium-regulated processes and the exceptional longevity of oocytes in the primate lineage, we propose that this microstructural variation may be an adaptive feature associated with high maternal expression of this Bcl-2 family member.     

Growth and Maximum Size of Tiger Sharks (Galeocerdo cuvier) in Hawaii

Tiger sharks (Galecerdo cuvier) are apex predators characterized by their broad diet, large size and rapid growth. Tiger shark maximum size is typically between 380 & 450 cm Total Length (TL), with a few individuals reaching 550 cm TL, but the maximum size of tiger sharks in Hawaii waters remains uncertain. A previous study suggested tiger sharks grow rather slowly in Hawaii compared to other regions, but this may have been an artifact of the method used to estimate growth (unvalidated vertebral ring counts) compounded by small sample size and narrow size range. Since 1993, the University of Hawaii has conducted a research program aimed at elucidating tiger shark biology, and to date 420 tiger sharks have been tagged and 50 recaptured. All recaptures were from Hawaii except a single shark recaptured off Isla Jacques Cousteau (24°13′17″N 109°52′14″W), in the southern Gulf of California (minimum distance between tag and recapture sites  =  approximately 5,000 km), after 366 days at liberty (DAL). We used these empirical mark-recapture data to estimate growth rates and maximum size for tiger sharks in Hawaii. We found that tiger sharks in Hawaii grow twice as fast as previously thought, on average reaching 340 cm TL by age 5, and attaining a maximum size of 403 cm TL. Our model indicates the fastest growing individuals attain 400 cm TL by age 5, and the largest reach a maximum size of 444 cm TL. The largest shark captured during our study was 464 cm TL but individuals >450 cm TL were extremely rare (0.005% of sharks captured). We conclude that tiger shark growth rates and maximum sizes in Hawaii are generally consistent with those in other regions, and hypothesize that a broad diet may help them to achieve this rapid growth by maximizing prey consumption rates.     

CDKAL1-Related Single Nucleotide Polymorphisms Are Associated with Insulin Resistance in a Cross-Sectional Cohort of Greek Children

Five novel loci recently found to be associated with body mass in two GWAS of East Asian populations were evaluated in two cohorts of Swedish and Greek children and adolescents. These loci are located within, or in the proximity of: CDKAL1, PCSK1, GP2, PAX6 and KLF9. No association with body mass has previously been reported for these loci in GWAS performed on European populations. The single nucleotide polymorphisms (SNPs) with the strongest association at each loci in the East Asian GWAS were genotyped in two cohorts, one obesity case control cohort of Swedish children and adolescents consisting of 496 cases and 520 controls and one cross-sectional cohort of 2293 nine-to-thirteen year old Greek children and adolescents. SNPs were surveyed for association with body mass and other phenotypic traits commonly associated with obesity, including adipose tissue distribution, insulin resistance and daily caloric intake. No association with body mass was found in either cohort. However, among the Greek children, association with insulin resistance could be observed for the two CDKAL1-related SNPs: rs9356744 (β = 0.018, p = 0.014) and rs2206734 (β = 0.024, p = 0.001). CDKAL1-related variants have previously been associated with type 2 diabetes and insulin response. This study reports association of CDKAL1-related SNPs with insulin resistance, a clinical marker related to type 2 diabetes in a cross-sectional cohort of Greek children and adolescents of European descent.     

Energy Balance Related Behaviour: Personal,Home- and Friend-Related Factors among Schoolchildren in Europe Studied in the ENERGY-Project

Objective

To design interventions that target energy balance-related behaviours, knowledge of primary schoolchildren''s perceptions regarding soft drink intake, fruit juice intake, breakfast consumption, TV viewing and physical activity (PA) is essential. The current study describes personal beliefs and attitudes, home- and friend-related variables regarding these behaviours across Europe.

Design

Cross-sectional study in which personal, family and friend -related variables were assessed by validated questionnaires, and dichotomized as favourable versus unfavourable answers. Logistic regression analyses were conducted to estimate proportions of children giving unfavourable answers and test between-country differences.

Setting

A survey in eight European countries.

Subjects

A total of 7903 10–12 year old primary schoolchildren.

Results

A majority of the children reported unfavourable attitudes, preferences and subjective norms regarding soft drink, fruit juice intake and TV viewing accompanied with high availability and accessibility at home. Few children reported unfavourable attitudes and preferences regarding breakfast consumption and PA. Many children reported unfavourable health beliefs regarding breakfast consumption and TV viewing. Substantial differences between countries were observed, especially for variables regarding soft drink intake, breakfast consumption and TV viewing.

Conclusion

The surveyed children demonstrated favourable attitudes to some healthy behaviours (PA, breakfast intake) as well as to some unhealthy behaviours (soft drink consumption, TV viewing). Additionally, many children across Europe have personal beliefs and are exposed to social environments that are not supportive to engagement in healthy behaviours. Moreover, the large differences in personal, family and friend-related variables across Europe argue for implementing different strategies in the different European countries.     

Imaging Mass Spectrometry Reveals Alterations in N-Linked Glycosylation That Are Associated With Histopathological Changes in Nonalcoholic Steatohepatitis in Mouse and Human

Nonalcoholic steatohepatitis (NASH) is the progressive form of nonalcoholic fatty liver disease (NAFLD) and is characterized by inflammation, hepatocyte injury, and fibrosis. Further, NASH is a risk factor for cirrhosis and hepatocellular carcinoma. Previous research demonstrated that serum N-glycan profiles can be altered in NASH patients. Here, we hypothesized that these N-glycan modifications may be associated with specific liver damage in NAFLD and NASH. To investigate the N-glycome profile in tissue, imaging mass spectrometry was used for a qualitative and quantitative in situ N-linked glycan analysis of mouse and human NAFLD/NASH tissue. A murine model was used to induce NAFLD and NASH through ad libitum feeding with either a high-fat diet or a Western diet, respectively. Mice fed a high-fat diet or Western diet developed inflammation, steatosis, and fibrosis, consistent with NAFLD/NASH phenotypes. Induction of NAFLD/NASH for 18 months using high caloric diets resulted in increased expression of mannose, complex/fucosylated, and hybrid N-glycan structures compared to control mouse livers. To validate the animal results, liver biopsy specimens from 51 human NAFLD/NASH patients representing the full range of NASH Clinical Research Network fibrosis stages were analyzed. Importantly, the same glycan alterations observed in mouse models were observed in human NASH biopsies and correlated with the degree of fibrosis. In addition, spatial glycan alterations were localized specifically to histopathological changes in tissue like fibrotic and fatty areas. We demonstrate that the use of standard staining’s combined with imaging mass spectrometry provide a full profile of the origin of N-glycan modifications within the tissue. These results indicate that the spatial distribution of abundances of released N-glycans correlate with regions of tissue steatosis associated with NAFLD/NASH.     

The Interaction of the Chemotherapeutic Drug Chlorambucil with Human Glutathione Transferase A1-1: Kinetic and Structural Analysis

Glutathione transferases (GSTs) are enzymes that contribute to cellular detoxification by catalysing the nucleophilic attack of glutathione (GSH) on the electrophilic centre of a number of xenobiotic compounds, including several chemotherapeutic drugs. In the present work we investigated the interaction of the chemotherapeutic drug chlorambucil (CBL) with human GSTA1-1 (hGSTA1-1) using kinetic analysis, protein crystallography and molecular dynamics. In the presence of GSH, CBL behaves as an efficient substrate for hGSTA1-1. The rate-limiting step of the catalytic reaction between CBL and GSH is viscosity-dependent and kinetic data suggest that product release is rate-limiting. The crystal structure of the hGSTA1-1/CBL-GSH complex was solved at 2.1 Å resolution by molecular replacement. CBL is bound at the H-site attached to the thiol group of GSH, is partially ordered and exposed to the solvent, making specific interactions with the enzyme. Molecular dynamics simulations based on the crystal structure indicated high mobility of the CBL moiety and stabilization of the C-terminal helix due to the presence of the adduct. In the absence of GSH, CBL is shown to be an alkylating irreversible inhibitor for hGSTA1-1. Inactivation of the enzyme by CBL followed a biphasic pseudo-first-order saturation kinetics with approximately 1 mol of CBL per mol of dimeric enzyme being incorporated. Structural analysis suggested that the modifying residue is Cys112 which is located at the entrance of the H-site. The results are indicative of a structural communication between the subunits on the basis of mutually exclusive modification of Cys112, indicating that the two enzyme active sites are presumably coordinated.     

Pollution by conspecifics as a component of intraspecific competition among Aedes aegypti larvae

Abstract.  1. The role of pollution by conspecifics in the costs associated with larval intraspecific competition was investigated for Aedes aegypti (Diptera: Culicidae).
2. The growth of larval A. aegypti mosquitoes reared in clean water and water in which another larva had previously grown was compared; this procedure eliminates interactions through food consumption between competitors and allows the effects of other processes to be expressed.
3. A cost of growing in polluted water was found: this cost was expressed as an increase in developmental time and a reduction of adult longevity when starved, starved adult dry weight, and wing length.
4. Contrary to previously reported results of an experiment allowing for competition for food, these costs were not expressed in a sex-specific manner and were independent of the sex of the polluter.
5. It was thus demonstrated that competition arises from both resource depletion and other effects that result in deterioration of the environment, with chemical pollution of the environment being the most likely cause.     

The impact of <Emphasis Type="Italic">MTHFR</Emphasis> 677C → T risk knowledge on changes in folate intake: findings from the Food4Me study

Background

It is hypothesised that individuals with knowledge of their genetic risk are more likely to make health-promoting dietary and lifestyle changes. The present study aims to test this hypothesis using data from the Food4Me study. This was a 6-month Internet-based randomised controlled trial conducted across seven centres in Europe where individuals received either general healthy eating advice or varying levels of personalised nutrition advice. Participants who received genotype-based personalised advice were informed whether they had the risk (CT/TT) (n?=?178) or non-risk (CC) (n?=?141) alleles of the methylenetetrahydrofolate reductase (MTHFR) gene in relation to cardiovascular health and the importance of a sufficient intake of folate. General linear model analysis was used to assess changes in folate intake between the MTHFR risk, MTHFR non-risk and control groups from baseline to month 6 of the intervention.

Results

There were no differences between the groups for age, gender or BMI. However, there was a significant difference in country distribution between the groups (p?=?0.010). Baseline folate intakes were 412?±?172, 391?±?190 and 410?±?186 μg per 10 MJ for the risk, non-risk and control groups, respectively. There were no significant differences between the three groups in terms of changes in folate intakes from baseline to month 6. Similarly, there were no changes in reported intake of food groups high in folate.

Conclusions

These results suggest that knowledge of MTHFR 677C?→?T genotype did not improve folate intake in participants with the risk variant compared with those with the non-risk variant.

Trial registration

ClinicalTrials.gov NCT01530139

     

Gene methylation parallelisms between peripheral blood cells and oral mucosa samples in relation to overweight

Epigenetics has an important role in the regulation of metabolic adaptation to environmental modifications. In this sense, the determination of epigenetic changes in non-invasive samples during the development of metabolic diseases could play an important role in the procedures in primary healthcare practice. To help translate the knowledge of epigenetics to public health practice, the present study aims to explore the parallelism of methylation levels between white blood cells and buccal samples in relation to obesity and associated disorders. Blood and buccal swap samples were collected from a subsample of the Spanish cohort of the Food4Me study. Infinium HumanMethylation450 DNA Analysis was carried out for the determination of methylation levels. Standard deviation for β values method and concordance correlation analysis were used to select those CpG which showed best parallelism between samples. A total of 277 CpGs met the criteria and were selected for an enrichment analysis and a correlation analysis with anthropometrical and clinical parameters. From those selected CpGs, four presented high associations with BMI (cg01055691 in GAP43; r = ?0.92 and rho = ?0.84 for blood; r = ?0.89 and rho = ?0.83 for buccal sample), HOMA-IR (cg00095677 in ATP2A3; r = 0.82 and rho = ?0.84 for blood; r = ?0.8 and rho = ?0.83 for buccal sample) and leptin (cg14464133 in ADARB2; r = ?0.9182 and rho = ?0.94 for blood; r = ?0.893 and rho = ?0.79 for buccal sample). These findings demonstrate the potential application of non-invasive buccal samples in the identification of surrogate epigenetic biomarkers and identify methylation sites in GAP43, ATP2A3 and ADARB2 genes as potential targets in relation to overweight management and insulin sensibility.