Dispersion of vendace eggs and larvae around potential nursery areas reveals their reproductive strategy

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Distinct haplotype structure at the innate immune receptor Toll‐like receptor 2 across bank vole populations and lineages in Europe

Parasite‐mediated selection may contribute to the maintenance of genetic variation at host immune genes over long time scales. To date, the best evidence for the long‐term maintenance of immunogenetic variation in natural populations comes from studies on the major histocompatibility complex (MHC) genes, whereas evidence for such processes from other immune genes remains scarce. In the present study, we show that, despite pronounced population differentiation and the occurrence of numerous private alleles within populations, the innate immune gene Toll‐like receptor 2 (TLR2) displays a distinct haplotype structure in 21 bank vole (Myodes glareolus) populations across Europe. Haplotypes from all populations grouped in four clearly differentiated clusters, with the three main clusters co‐occurring in at least three previously described mitochondrial lineages. This pattern indicates that the distinct TLR2 haplotype structure may precede the split of the mitochondrial lineages 0.19–0.56 Mya and suggests that haplotype clusters at this innate immune receptor are maintained over prolonged time in wild bank vole populations.     

Non-Employment Histories of Middle-Aged Men and Women Who Died from Alcohol-Related Causes: A Longitudinal Retrospective Study

Background

Long-term patterning of non-employment among problem drinkers is poorly understood. We determined the level and timing of non-employment, and the relative contribution of various types of non-employment among middle-aged persons who died of alcohol-related causes.

Methods

We conducted a longitudinal retrospective register-based study of Finnish men and women aged 45–64 years who died of alcohol-related causes (n = 15 552) or other causes (n = 39 166) in the period 2000–07, or who survived (n = 204 422) until the end of 2007. We traced back the number of days in employment and non-employment for up to 17 years before death or before the end of the study period for the survivors.

Results

The majority (≥56%) of persons who died of alcohol-related causes were in employment up to ten years before death. Over the 17-year period before death, those who died of alcohol-related causes were in employment on average two years less (mean 6.3 years, 95%CI 6.2–6.4) than those dying of other causes (8.2, 8.1–8.3), and five years less than survivors (11.6, 11.5–11.7), when sex and age were adjusted for. The relative role of various types of non-employment differed markedly across the two mortality groups. Among those who died of alcohol-related causes, unemployment accounted for 54% of the total burden of non-employment, in comparison with 29% among those who died of other causes. In contrast, disability pension accounted for 41% of the total burden of non-employment among those who died of alcohol-related causes, but 65% among those who died of other causes.

Conclusions

The results indicate the feasibility of preventing movement out of employment among middle-aged men and women with severe alcohol-related harm, provided that they are identified early on during their working careers and offered effective interventions.     

Seasonal variation in the regulation of redox state and some biotransformation enzyme activities in the barn swallow (Hirundo rustica L.)

Little is known of the normal seasonal variation in redox state and biotransformation activities in birds. In long-distance migratory birds, in particular, seasonal changes could be expected to occur because of the demands of migration and reproduction. In this study, we measured several redox parameters in the barn swallow (Hirundo rustica L.) during the annual cycle. We captured the wintering barn swallows before spring migration in South Africa, and we captured the barn swallows that arrived in spring, bred in summer, and migrated in autumn in Finland. The redox status and biotransformation activities of barn swallows varied seasonally. Wintering birds in South Africa had high biotransformation activities and appeared to experience oxidative stress, whereas in spring and summer, they showed relatively low redox (superoxide dismutase [SOD], catalase [CAT], and glutathione reductase [GR]) and biotransformation enzyme activities. Autumn birds had very low biotransformation enzyme activities and low indication of oxidative stress but high activity of some redox enzymes (GR and glucose 6-phosphate dehydrogenase [G6PDH]). High activities of some redox enzymes (SOD, GR, and G6PDH) seem to be related to migration, whereas low activities of some redox enzymes (SOD, CAT, and GR) may be associated with breeding. Barn swallows in South Africa may experience pollution-related oxidative stress, which may hamper interpretation of normal seasonal variation in redox parameters.     

Characterization of Drosophila GDNF Receptor-Like and Evidence for Its Evolutionarily Conserved Interaction with Neural Cell Adhesion Molecule (NCAM)/FasII

Background

Glial cell line-derived neurotrophic factor (GDNF) family ligands are secreted growth factors distantly related to the TGF-β superfamily. In mammals, they bind to the GDNF family receptor α (Gfrα) and signal through the Ret receptor tyrosine kinase. In order to gain insight into the evolution of the Ret-Gfr-Gdnf signaling system, we have cloned and characterized the first invertebrate Gfr-like cDNA (DmGfrl) from Drosophila melanogaster and generated a DmGfrl mutant allele.

Results

We found that DmGfrl encodes a large GPI-anchored membrane protein with four GFR-like domains. In line with the fact that insects lack GDNF ligands, DmGfrl mediated neither Drosophila Ret phosphorylation nor mammalian RET phosphorylation. In situ hybridization analysis revealed that DmGfrl is expressed in the central and peripheral nervous systems throughout Drosophila development, but, surprisingly, DmGfrl and DmRet expression patterns were largely non-overlapping. We generated a DmGfrl null allele by genomic FLP deletion and found that both DmGfrl null females and males are viable but display fertility defects. The female fertility defect manifested as dorsal appendage malformation, small size and reduced viability of eggs laid by mutant females. In male flies DmGfrl interacted genetically with the Drosophila Ncam (neural cell adhesion molecule) homolog FasII to regulate fertility.

Conclusion

Our results suggest that Ret and Gfrl did not function as an in cis receptor-coreceptor pair before the emergence of GDNF family ligands, and that the Ncam-Gfr interaction predated the in cis Ret-Gfr interaction in evolution. The fertility defects that we describe in DmGfrl null flies suggest that GDNF receptor-like has an evolutionarily ancient role in regulating male fertility and a previously unrecognized role in regulating oogenesis.

Significance

These results shed light on the evolutionary aspects of the structure, expression and function of Ret-Gfrα and Ncam-Gfrα signaling complexes.