The antiviral efficacy of HIV-specific CD8⁺ T-cells to a conserved epitope is heavily dependent on the infecting HIV-1 isolate

A major challenge to developing a successful HIV vaccine is the vast diversity of viral sequences, yet it is generally assumed that an epitope conserved between different strains will be recognised by responding T-cells. We examined whether an invariant HLA-B8 restricted Nef_90–97 epitope FL8 shared between five high titre viruses and eight recombinant vaccinia viruses expressing Nef from different viral isolates (clades A–H) could activate antiviral activity in FL8-specific cytotoxic T-lymphocytes (CTL). Surprisingly, despite epitope conservation, we found that CTL antiviral efficacy is dependent on the infecting viral isolate. Only 23% of Nef proteins, expressed by HIV-1 isolates or as recombinant vaccinia-Nef, were optimally recognised by CTL. Recognition of the HIV-1 isolates by CTL was independent of clade-grouping but correlated with virus-specific polymorphisms in the epitope flanking region, which altered immunoproteasomal cleavage resulting in enhanced or impaired epitope generation. The finding that the majority of virus isolates failed to present this conserved epitope highlights the importance of viral variance in CTL epitope flanking regions on the efficiency of antigen processing, which has been considerably underestimated previously. This has important implications for future vaccine design strategies since efficient presentation of conserved viral epitopes is necessary to promote enhanced anti-viral immune responses.     

MVPA is associated with lower weight gain in 8-10 year old children: a prospective study with 1 year follow-up

Background

Studies relating physical activity (PA) to weight gain in children have produced mixed results, although there is some evidence for stronger associations with more intense physical activities. The present study tested the hypothesis that weight gain over one year in 8–10 year olds would be more strongly predicted by moderate and vigorous physical activity (MVPA) than total physical activity (total PA) or sedentary behaviour.

Methodology

Participants were 280 children taking part in the Physical Exercise and Appetite in Children Study (PEACHES). Weight status was assessed using body mass index (BMI), fat mass index (FMI), and waist circumference (WC) in school Year 4 (baseline; age 8.7 yrs) and Year 5 (follow-up; age 9.7 yrs). Physical activity was measured at baseline using the Actigraph GT1M accelerometer to assess total PA (mean accelerometers counts per minute), MVPA; ≥4000 counts per minute) and sedentary time (<100 counts per minute).

Principal Findings

After adjustment for baseline BMI, SES, sex and ethnicity, MVPA was significantly associated with follow–up BMI (adjusted β = −0.07; p = 0.002). This association was independent of total PA or sedentary time. Similar results were observed for FMI; again MVPA was significantly associated with follow up FMI (β = −0.16; p = 0.001) independent of total PA or sedentary time. The pattern was similar for WC (β = −0.07), but the association between MVPA and WC did not reach significance at p = 0.06.

Conclusion

The results of this study strongly support promotion of MVPA in children.     

The social network: deciphering fungal language

It has been estimated that up to one quarter of the world's biomass is of fungal origin, comprising approximately 1.5 million species. In order to interact with one another and respond to environmental cues, fungi communicate with their own chemical languages using a sophisticated series of extracellular signals and cellular responses. A new appreciation for the linkage between these chemical languages and developmental processes in fungi has renewed interest in these signalling molecules, which can now be studied using post-genomic resources. In this Review, we focus on the molecules that are secreted by the largest phylum of fungi, the Ascomycota, and the quest to understand their biological function.     

Serotonin transporter genotype (5-HTTLPR) predicts utilitarian moral judgments

Background

The psychological and neurobiological processes underlying moral judgment have been the focus of extensive recent research. Here we show that serotonin transporter (5-HTTLPR) genotype predicts responses to moral dilemmas featuring foreseen harm to an innocent.

Methodology/Principal Findings

Participants in this study judged the acceptability of actions that would unintentionally or intentionally harm an innocent victim in order to save others'' lives. An analysis of variance revealed a genotype × scenario interaction, F(2, 63) = 4.52, p = .02. Results showed that, relative to long allele homozygotes (LL), carriers of the short (S) allele showed particular reluctance to endorse utilitarian actions resulting in foreseen harm to an innocent individual. LL genotype participants rated perpetrating unintentional harm as more acceptable (M = 4.98, SEM = 0.20) than did SL genotype participants (M = 4.65, SEM = 0.20) or SS genotype participants (M = 4.29, SEM = 0.30). No group differences in moral judgments were observed in response to scenarios featuring intentional harm.

Conclusions/Significance

The results indicate that inherited variants in a genetic polymorphism that influences serotonin neurotransmission influence utilitarian moral judgments as well. This finding is interpreted in light of evidence that the S allele is associated with elevated emotional responsiveness.     

Ufd1 exhibits the AAA-ATPase fold with two distinct ubiquitin interaction sites

Ufd1 mediates ubiquitin fusion degradation by association with Npl4 and Cdc48/p97. The Ufd1-ubiquitin interaction is essential for transfer of substrates to the proteasome. However, the mechanism and specificity of ubiquitin recognition by Ufd1 are poorly understood due to the lack of detailed structural information. Here, we present the solution structure of yeast Ufd1 N domain and show that it has two distinct binding sites for mono- and polyubiquitin. The structure exhibits striking similarities to the Cdc48/p97 N domain. It contains the double-psi beta barrel motif, which is thus identified as a ubiquitin binding domain. Significantly, Ufd1 shows higher affinity toward polyubiquitin than monoubiquitin, attributable to the utilization of separate binding sites with different affinities. Further studies revealed that the Ufd1-ubiquitin interaction involves hydrophobic contacts similar to those in well-characterized ubiquitin binding proteins. Our results provide a structural basis for a previously proposed synergistic binding of polyubiquitin by Cdc48/p97 and Ufd1.     

Functions of adaptor protein (AP)-3 and AP-1 in tyrosinase sorting from endosomes to melanosomes

Specialized cells exploit adaptor protein complexes for unique post-Golgi sorting events, providing a unique model system to specify adaptor function. Here, we show that AP-3 and AP-1 function independently in sorting of the melanocyte-specific protein tyrosinase from endosomes to the melanosome, a specialized lysosome-related organelle distinguishable from lysosomes. AP-3 and AP-1 localize in melanocytes primarily to clathrin-coated buds on tubular early endosomes near melanosomes. Both adaptors recognize the tyrosinase dileucine-based melanosome sorting signal, and tyrosinase largely colocalizes with each adaptor on endosomes. In AP-3-deficient melanocytes, tyrosinase accumulates inappropriately in vacuolar and multivesicular endosomes. Nevertheless, a substantial fraction still accumulates on melanosomes, concomitant with increased association with endosomal AP-1. Our data indicate that AP-3 and AP-1 function in partially redundant pathways to transfer tyrosinase from distinct endosomal subdomains to melanosomes and that the AP-3 pathway ensures that tyrosinase averts entrapment on internal membranes of forming multivesicular bodies.     

A rapid method for promoter exchange in Aspergillus nidulans using recombinant PCR

Recombinant PCR has been used to generate linear fragments for promoter replacement by transformation in Aspergillus nidulans. A cassette vector carrying the pyr-4 non-homologous selectable marker and conditional promoter Pr-alcA was constructed for use as a template for PCR, and is suitable for testing the function of essential genes. Two genes involved in polar growth, cotA and bemA, were used to assess the system. Efficient targeting was possible with both genes using approximately 500bp of flanking homologous sequence. Depending on yield, the linear PCR product could be used directly for transformation, or after first cloning into a suitable vector. bemA, a putative homologue of the Saccharomyces cerevisiae BEM1 gene was identified through sequence comparison. In A. nidulans, this protein appears to have a similar role to the yeast Bem1p, which acts as a scaffold protein involved in the establishment of cell polarity.     

Knowledge, attitudes, and utilization of BRCA1/2 testing among women with early-onset breast cancer

A total of 2,400 questionnaires were mailed to members of two mid-Atlantic breast cancer awareness/support groups to investigate the association between attitudes, knowledge, and use of BRCA1/2 testing among women with early-onset breast cancer. Of the 493 (21%) questionnaires returned, 406 respondents had a diagnosis of breast cancer, of whom 248 were diagnosed prior to age 50 and included in the analyses. Eighty-three percent (206/248) of these women had heard of BRCA1/2 testing and 12.5% (31/248) had undergone BRCA1/2 testing. Among women who had heard of BRCA1/2 testing, women who had been tested were younger (p = 0.03), more likely to have a college education (p = 0.03), more likely to have a family member who had undergone BRCA1/2 testing (p = 0.005), and had greater knowledge, more positive attitudes, and fewer negative attitudes about BRCA1/2 testing (p = 0.02, p = 0.004, and p = 0.004, respectively). In this sample, knowledge regarding BRCA1/2 testing is high, but uptake of genetic testing is low. Lack of information regarding how genetic testing might alter health-care decisions and fear about the genetic testing procedure, its costs, and possible false-positive results are associated with low uptake of genetic testing. Further education regarding these specific points may enhance the use of genetic testing.