Aerobic training increases the expression of adiponectin receptor genes in the peripheral blood mononuclear cells of young men

Little is known about the effect of exercise training on the expression of adiponectin receptor genes in peripheral blood mononuclear cells (PBMCs). In this study, we investigated the effects of aerobic training on the expression of AdipoR1 and AidpoR2 mRNAs in PBMCs, whole body insulin sensitivity, and circulating adiponectins in men. Thirty young men were randomly assigned to either a control (n=15) or an exercise (n=15) group. Subjects assigned to the exercise group underwent a 12-week jogging and/or running programme on a motor-driven treadmill at an intensity of 60%-75% of the age-based maximum heart rate with duration of 40 minutes per session and a frequency of 5 days per week. Two-way mixed ANOVA with repeated measures was used to test any significant time-by-group interaction effects for the measured variables at p=0.05. We found significant time-by-group interaction effects for waist circumference (p=0.001), VO_2max (p<0.001), fasting insulin (p=0.016), homeostasis model assessment for insulin resistance (HOMA-IR) (p=0.010), area under the curve (AUC) for insulin response during the 75-g oral glucose tolerance test (p=0.002), high-molecular weight (HMW) adiponectin (p=0.016), and the PBMC mRNA levels of AdipoR1 (p<0.001) and AdipoR2 (p=0.001). The exercise group had significantly increased mRNA levels of AdipoR1 and AdipoR2 in PBMCs, along with increased whole body insulin sensitivity and HMW adiponectin, decreased waist circumference, and increased VO_2max compared with the control group. In summary, the current findings suggest that exercise training modulates the expression of AdipoR1 and AdipoR2 mRNAs in PBMCs, implying that manipulation of the expression of these genes could be a potential surrogate for lifestyle intervention-mediated improvements of whole body insulin sensitivity and glucose homeostasis.     

Bucking the trend: the African Black Oystercatcher as a recent conservation success story

The African Black Oystercatcher Haematopus moquini is a charismatic, southern African near-endemic, wader species, that is often seen as a flagship species for coastal bird conservation, as it was recently down-listed regionally to Least Concern on the IUCN Red List of Threatened Species. To celebrate this rare conservation success story, BirdLife South Africa named it the 2018 Bird of the Year and ran a year-long programme in collaboration with the Nature’s Valley Trust highlighting aspects of the species’ biology, current threats, and conservation success. We used data collected by the Southern African Bird Atlas Project (SABAP1 and SABAP2) to examine changes in the species’ range and relative abundance, both in the records between the two projects, as well as trends within the SABAP2 sampling period (2008–2017). This case study enabled us to assess whether such metrics can accurately reflect abundance and distributional changes in a species. We found increases in the reported range and the reporting rates between the two Atlas projects, and that the SABAP2 reporting rate was stable. Regionally, across four coastal categories, the reporting rate was lowest in KwaZulu-Natal, though this region also showed an increase in the probability of reporting during the SABAP2 period. While corroborating the recent change in the species’ conservation status, we also provide good evidence that the long-term SABAP data can be used successfully to assess population trends and range changes over time.     

Lysosomal localization of ubiquitinated Jun requires multiple determinants in a lysine-27-linked polyubiquitin conjugate

Ubiquitination regulates many cellular functions, including protein localization and degradation. Each function is specified by unique determinants in the conjugate. Ubiquitinated Jun is localized to lysosomes for degradation. Here, we characterized determinants of Jun ubiquitination and lysosomal localization by using ubiquitin-mediated fluorescence complementation (UbFC) in living cells and analysis of the stoichiometry of ubiquitin linked to Jun extracted from cells. The δ region of Jun and isoleucine-44 in ubiquitin were required for lysosomal localization of the conjugate. Ubiquitin containing only lysine-27, but no other single-lysine ubiquitin, mediated Jun ubiquitination, albeit at lower stoichiometry than wild-type ubiquitin. These conjugates were predominantly nuclear, but coexpression of lysine-27 and lysine-less ubiquitins enhanced the mean stoichiometry of Jun ubiquitination and lysosomal localization of the conjugate. Hepatocyte growth factor-regulated tyrosine kinase substrate (HRS) and tumor susceptibility gene 101 (TSG101) colocalized with ubiquitinated Jun. Knockdown of HRS or TSG101 inhibited lysosomal localization of ubiquitinated Jun and reduced Jun turnover. Ubiquitination of other Fos and Jun family proteins had distinct effects on their localization. Our results indicate that Jun is polyubiquitinated by E3 ligases that produce lysine-27–linked chains. Lysosomal localization of the conjugate requires determinants in Jun and in ubiquitin that are recognized in part by TSG101 and HRS, facilitating selective translocation and degradation of ubiquitinated Jun.