Malonyl-CoA Mediates Leptin Hypothalamic Control of Feeding Independent of Inhibition of CPT-1a

Hypothalamic fatty acid metabolism is involved in central nervous system controls of feeding and energy balance. Malonyl-CoA, an intermediate of fatty acid biosynthesis, is emerging as a significant player in these processes. Notably, hypothalamic malonyl-CoA has been implicated in leptin's feeding effect. Leptin treatment increases malonyl-CoA level in the hypothalamic arcuate nucleus (Arc), and this increase is required for leptin-induced decrease in food intake. However, the intracellular downstream mediators of malonyl-CoA's feeding effect have not been identified. A primary biochemical action of malonyl-CoA is the inhibition of the acyltransferase activity of carnitine palmitoyltransferase-1 (CPT-1). In the hypothalamus, the predominant isoform of CPT-1 that possesses the acyltransferase activity is CPT-1 liver type (CPT-1a). To address the role of CPT-1a in malonyl-CoA's anorectic action, we used a recombinant adenovirus expressing a mutant CPT-1a that is insensitive to malonyl-CoA inhibition. We show that Arc overexpression of the mutant CPT-1a blocked the malonyl-CoA-mediated inhibition of CPT-1 activity. However, the overexpression of this mutant did not affect the anorectic actions of leptin or central cerulenin for which an increase in Arc malonyl-CoA level is also required. Thus, CPT-1a does not appear to be involved in the malonyl-CoA's anorectic actions induced by leptin. Furthermore, long-chain fatty acyl-CoAs, substrates of CPT-1a, dissociate from malonyl-CoA's actions in the Arc under different feeding states. Together, our results suggest that Arc intracellular mechanisms of malonyl-CoA's anorectic actions induced by leptin are independent of CPT-1a. The data suggest that target(s), rather than CPT-1a, mediates malonyl-CoA action on feeding

An inhibitory role for FAK in regulating proliferation: a link between limited adhesion and RhoA-ROCK signaling

Focal adhesion kinase (FAK) transduces cell adhesion to the extracellular matrix into proliferative signals. We show that FAK overexpression induced proliferation in endothelial cells, which are normally growth arrested by limited adhesion. Interestingly, displacement of FAK from adhesions by using a FAK−/− cell line or by expressing the C-terminal fragment FRNK also caused an escape of adhesion-regulated growth arrest, suggesting dual positive and negative roles for FAK in growth regulation. Expressing kinase-dead FAK-Y397F in FAK−/− cells prevented uncontrolled growth, demonstrating the antiproliferative function of inactive FAK. Unlike FAK overexpression–induced growth, loss of growth control in FAK−/− or FRNK-expressing cells increased RhoA activity, cytoskeletal tension, and focal adhesion formation. ROCK inhibition rescued adhesion-dependent growth control in these cells, and expression of constitutively active RhoA or ROCK dysregulated growth. These findings demonstrate the ability of FAK to suppress and promote growth, and underscore the importance of multiple mechanisms, even from one molecule, to control cell proliferation

Influence of PB2 host-range determinants on the intranuclear mobility of the influenza A virus polymerase

Avian influenza A viruses often do not propagate efficiently in mammalian cells. The viral polymerase protein PB2 is important for this host restriction, with amino-acid polymorphisms at residue 627 and other positions acting as ‘signatures’ of avian- or human-adapted viruses. Restriction is hypothesized to result from differential interactions (either positive or inhibitory) with unidentified cellular factors. We applied fluorescence recovery after photobleaching (FRAP) to investigate the mobility of the viral polymerase in the cell nucleus using A/PR/8/34 and A/Turkey/England/50-92/91 as model strains. As expected, transcriptional activity of a polymerase with the avian PB2 protein was strongly dependent on the identity of residue 627 in human but not avian cells, and this correlated with significantly slower diffusion of the inactive polymerase in human but not avian nuclei. In contrast, the activity and mobility of the PR8 polymerase was affected much less by residue 627. Sequence comparison followed by mutagenic analyses identified residues at known host-range-specific positions 271, 588 and 701 as well as a novel determinant at position 636 as contributors to host-specific activity of both PR8 and Turkey PB2 proteins. Furthermore, the correlation between poor transcriptional activity and slow diffusional mobility was maintained. However, activity did not obligatorily correlate with predicted surface charge of the 627 domain. Overall, our data support the hypothesis of a host nuclear factor that interacts with the viral polymerase and modulates its activity. While we cannot distinguish between positive and inhibitory effects, the data have implications for how such factors might operate

Development and validity of a mentally-passive and mentally-active sedentary time questionnaire in nursing college students

ObjectiveThis study aimed to develop and validate a questionnaire to evaluate nursing college students’ mentally-passive and mentally-active sedentary time (M-PAST) in China.MethodsAn initial M-PAST questionnaire with mentally-passive and mentally-active sedentary behaviors was developed with content validity undertaken through a consensus panel and pilot test where a convenience sample of six nursing students was recruited to assess the relevance, comprehensiveness, and comprehensibility of the refined questionnaire after expert panelists’ responses. A cross-sectional online survey using a self-reported questionnaire was distributed to nursing students by email and then conducted using exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) to assess the construct validity of the M-PAST questionnaire and factor structures. Finally, the criterion validity was examined by exploring the associations between the M-PAST and the IPAQ sitting time, psychological distress, and insomnia.ResultsEight items regarding learning and leisure were included in the final version of the M-PAST questionnaire. A group of 650 nursing college students in China completed the study. Principal component analysis revealed two factors (i.e., mentally-passive and mentally-active sedentary behaviors), which explained 41.98% of the variance contributing to the questionnaire. The CFA reached the adaptive standard. Cronbach’s α ranged from 0.730 to 0.742. The correlations between M-PAST and IPAQ total sitting time were significant (p < 0.01, r = 0.125–0.396). Mentally-passive sedentary time was associated with psychological distress and insomnia (p < 0.01, r = 0.078–0.163), while no significant associations were found in mentally-active sedentary behaviors.Conclusion and implications for practiceThe M-PAST questionnaire appears to be a reliable and valid tool that reported both mentally-passive and mentally-active sedentary behaviors in nursing college students in China. However, future studies may need to further examine its validity among international nursing college students. This study further confirmed that mentally-passive sedentary behavior was positively associated with psychological distress and insomnia. Effective strategies are needed to reduce nursing college students’ mentally-passive sedentary time to improve their health and wellbeing in China

Spotty Liver Disease and Risk Factors

Presentation made at the 2021 Australasian Veterinary Poultry Association (AVPA) Annual Scientific Meeting via Zoom

Customer Behavioral Trends in Online Grocery Shopping During COVID-19

The evolution of online shopping started when big players like Amazon began selling all types of merchandise. Customers understood the ease of shopping online, so the trend grew even stronger. It is therefore essential to conduct a study of online shopping usage and the perception of customers during COVID-19, especially in the grocery sector. In this study, approximately 28 respondents from 50 specifically targeted groups were surveyed, and data collection was undertaken through a structured questionnaire. The regression method was conducted to analyze the collected data. Additionally, 5 interviews were conducted to validate and support the findings. Customers definitely preferred online grocery shopping (OGS) services during COVID-19 due to safety, convenience, and government restrictions. The influential factors were very important in this case, like delivery times, good discounts, and the quality of products. Secondly, OGS services were more stable and alert during the pandemic situation, following the government’s rules and restrictions. Customers were extremely satisfied with the safety precautions during COVID-19, the assistance provided through helplines for support, and the increased customer reach to make groceries as accessible as other reputable online departments