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The isolation of the Koala retrovirus-like virus from Australian megabats and the identification of endogenous retroviruses in the bat genome have raised questions on bat susceptibility to retroviruses in general. To answer this, we studied the susceptibility of 12 cell lines from 11 bat species to four well-studied retroviruses (human and simian immunodeficiency viruses [HIV and SIV] and murine leukemia viruses [Band N-MLV]). Systematic comparison of retroviral susceptibility among bats revealed that megabat cell lines were overall less susceptible to the four retroviruses than microbat cell lines, particularly to HIV-1 infection, whereas lineage-specific differences were observed for MLV susceptibility. Quantitative PCR of reverse transcription (RT) products, infection in heterokaryon cells, and point mutation analysis of the capsid (CA) revealed that (i) HIV-1 and MLV replication were blocked at the nuclear transport of the pre-integration complexes and before and/or during RT, respectively, and (ii) the observed lineage- specific restriction can be attributed to a dominant cellular factor constrained by specific positions in CA. Investigation of bat homologs of the three previously reported post-entry restriction factors constrained by the same residues in CA, tripartite motifprotein 5 a (TRIM5 a), myxovirus resistance 2/B (Mx2/MxB), and carboxy terminus-truncated cleavage and polyadenylation factor 6 (CPSF6-358), demonstrated poor anti-HIV-1 activity in megabat cells, whereas megabat TRIM5 a restricted MLV infection, suggesting that the major known CA-dependent restriction factors were not dominant in the observed lineage-specific susceptibility to HIV-1 in bat cells. Therefore, HIV-1 susceptibility of megabat cells may be determined in a manner distinct from that of primate cells. IMPORTANCE Recent studies have demonstrated the circulation of gammaretroviruses among megabats in Australia and the bats' resistance to HIV-1 infection; however, the origins of these viruses in megabats and the contribution of bats to retrovirus spread to other mammalian species remains unclear. To determine the intrinsic susceptibility of bat cells to HIV-1 infection, we investigated 12 cell lines isolated from 11 bat species. We report that lineage-specific retrovirus restriction in the bat cell lines can be attributed to CA-dependent factors. However, in the megabat cell lines examined, factors known to bind capsid and block infection in primate cell culture, including homologs of TRIM5 a, Mx2/MxB, and CPSF6, failed to exhibit significant anti-HIV-1 activities. These results suggested that the HIV-1 susceptibility of megabat cells occurs in a manner distinct from that of primate cells, where cellular factors, other than major known CA-dependent restriction factors, with lineage-specific functions could recognize retroviral proteins in megabats. [ABSTRACT FROM AUTHOR]

Introduction: As the population ages, more attention for emergent problems of health and disease in the elderly is needed. The International Union of Nutritional Sciences (IUNS) subcommittee on Nutrition and Ageing, in conjunction with the World Health Organization (WHO) global program for the elderly, embarked on the 'Food Habits in Later Life' (FHILL): a cross-cultural study to test key hypotheses in relation to food habits, health status and social variables in the elderly in 1987. That obesity is associated with increased morbidity and mortality requires specific consideration with advancing years. Objective: To investigate whether the so-called a healthy BMI (a widely used and simple tool to measure body fatness), between 20-25 kg/m², predicts 7-year survival amongst elderly (aged 70 years and over) from long-lived cultures namely Japanese in Japan, Swedes in Sweden, Anglo-Celtics in Australia, and Greeks in Greece and Australia. Methods: Baseline data of height and weight were used to calculate BMI from FHILL study participants (n=785). BMI was classified as low (BMI<20), healthy (20≤BMI<25), overweight (25≤BMI<30), and obesity (BMI≥30). Healthy BMI was used as a reference point. All cause mortality from up to seven years follow-up was used as study endpoint. Each Cox Proportional Hazard model was adjusted to age at enrolment (in 5-year intervals), gender, smoking and general health status and was developed to analyse the survival data. Results: Having a low BMI or being underweight/undernutrition (RR 1.45: 95% CI 0.85-2.58), being overweight (RR 1.16; 95% CI 0.75-1.78), or being obese (RR 0.97: 95% CI 0.55-1.74) did not significantly reduce or increase mortality as opposed to being in a healthy BMI group in the FHILL population. Conclusions: The FHILL study shows that mortality advantage conferred by having healthy BMI was not evident amongst elderly from longevity cultures. Body fatness, following adjustment for age at enrolment, gender, smoking, and general health status, was not found to be a significant predictor of 7-year survival. Further research may provide better understanding of the relation between optimal BMI and survival amongst older people. [ABSTRACT FROM AUTHOR]