Cortisol enhances aerobic metabolism and locomotor performance during the transition to land in an amphibious fish.

Amphibious fishes on land encounter higher oxygen (O2) availability and novel energetic demands, which impacts metabolism. Previous work on the amphibious mangrove killifish (Kryptolebias marmoratus) has shown that cortisol becomes elevated in response to air exposure, suggesting a possible role in regulating metabolism as fish move into terrestrial environments. We tested the hypothesis that cortisol is the mechanism by which oxidative processes are upregulated during the transition to land in amphibious fishes. We used two groups of fish, treated fish (+metyrapone, a cortisol synthesis inhibitor) and control (-metyrapone), to determine the impact of cortisol during air exposure (0 and 1 h, 7 days) on O2 consumption, terrestrial locomotion, the phenotype of red skeletal muscle, and muscle lipid concentration. Metyrapone-treated fish had an attenuated elevation in O2 consumption rate during the water to air transition and an immediate reduction in terrestrial exercise performance relative to control fish. In contrast, we found no short- (0 h) or long-term (7 days) differences between treatments in the oxidative phenotype of red muscles, nor in muscle lipid concentrations. Our results suggest that cortisol stimulates the necessary increase in aerobic metabolism needed to fuel the physiological changes that amphibious fishes undergo during the acclimation to air, although further studies are required to determine specific mechanisms of cortisol regulation.

Expanding the Curriculum in a School of Public Health.

Public health education has long been concentrated in a core set of public health disciplines such as epidemiology, biostatistics, and environmental health. Despite leaps forward in our understanding of the myriad influences on public health, little has changed in the organization of our educational systems. One issue brought to the forefront of public consciousness by the COVID-19 pandemic is the importance of leisure experiences, such as nature walks, to mental and physical well-being. In this descriptive best practice article, we discuss our approach to expanding the notion of a school of public health and provide examples of how disciplines and subjects outside of the "norms" of public health education, including leisure studies, can help better prepare students for their future in the field. Leisure studies is just one of many subject areas that can add value to public health pedagogy, and we envision many other subject areas and departments integrating into schools of public health in the future.

Coordinated roles of SLX4 and MutSß in DNA repair and the maintenance of genome stability.

SLX4 provides a molecular scaffold for the assembly of multiple protein complexes required for the maintenance of genome stability. It is involved in the repair of DNA crosslinks, the resolution of recombination intermediates, the response to replication stress and the maintenance of telomere length. To carry out these diverse functions, SLX4 interacts with three structure-selective endonucleases, MUS81-EME1, SLX1 and XPF-ERCC1, as well as the telomere binding proteins TRF2, RTEL1 and SLX4IP. Recently, SLX4 was shown to interact with MutSß, a heterodimeric protein involved in DNA mismatch repair, trinucleotide repeat instability, crosslink repair and recombination. Importantly, MutSß promotes the pathogenic expansion of CAG/CTG trinucleotide repeats, which is causative of myotonic dystrophy and Huntington's disease. The colocalization and specific interaction of MutSß with SLX4, together with their apparently overlapping functions, are suggestive of a common role in reactions that promote DNA maintenance and genome stability. This review will focus on the role of SLX4 in DNA repair, the interplay between MutSß and SLX4, and detail how they cooperate to promote recombinational repair and DNA crosslink repair. Furthermore, we speculate that MutSß and SLX4 may provide an alternative cellular mechanism that modulates trinucleotide instability.

MutSß Stimulates Holliday Junction Resolution by the SMX Complex.

MutSα and MutSß play important roles in DNA mismatch repair and are linked to inheritable cancers and degenerative disorders. Here, we show that MSH2 and MSH3, the two components of MutSß, bind SLX4 protein, a scaffold for the assembly of the SLX1-SLX4-MUS81-EME1-XPF-ERCC1 (SMX) trinuclease complex. SMX promotes the resolution of Holliday junctions (HJs), which are intermediates in homologous recombinational repair. We find that MutSß binds HJs and stimulates their resolution by SLX1-SLX4 or SMX in reactions dependent upon direct interactions between MutSß and SLX4. In contrast, MutSα does not stimulate HJ resolution. MSH3-depleted cells exhibit reduced sister chromatid exchanges and elevated levels of homologous recombination ultrafine bridges (HR-UFBs) at mitosis, consistent with defects in the processing of recombination intermediates. These results demonstrate a role for MutSß in addition to its established role in the pathogenic expansion of CAG/CTG trinucleotide repeats, which is causative of myotonic dystrophy and Huntington's disease.

A nitrogenase-like enzyme system catalyzes methionine, ethylene, and methane biogenesis.

Bacterial production of gaseous hydrocarbons such as ethylene and methane affects soil environments and atmospheric climate. We demonstrate that biogenic methane and ethylene from terrestrial and freshwater bacteria are directly produced by a previously unknown methionine biosynthesis pathway. This pathway, present in numerous species, uses a nitrogenase-like reductase that is distinct from known nitrogenases and nitrogenase-like reductases and specifically functions in C-S bond breakage to reduce ubiquitous and appreciable volatile organic sulfur compounds such as dimethyl sulfide and (2-methylthio)ethanol. Liberated methanethiol serves as the immediate precursor to methionine, while ethylene or methane is released into the environment. Anaerobic ethylene production by this pathway apparently explains the long-standing observation of ethylene accumulation in oxygen-depleted soils. Methane production reveals an additional bacterial pathway distinct from archaeal methanogenesis.

Investigating the effects of behavioral change, social support, and self-efficacy in physical activity in a collectivistic culture: Application of Stages of Motivational Readiness for Change in Korean young adults.

The study investigated the roles of social support, self-efficacy, and behavioral change in physical activity (PA) in the Korean culture. The subjects were 164 Korean college students. In November 2016, the study participants completed an online survey asking about PA behavior, PA Self-Efficacy, PA Stages of Change (stages of behavioral change in PA), and Social Support for PA. The collected data were statistically analyzed through structural equation modeling. In the results, PA Stages of Change had a direct effect (ß = 0.57, p < .01) on PA with an explanatory power of r2 = 0.46. Moreover, PA Self-Efficacy had an indirect (ßindirect = 0.29) effect on PA through PA Stages of Change as PA Self-Efficacy had a direct effect (ß = 0.50, p < .001) on PA Stages of Change. However, Social Support for PA did not show an effect on other factors. Additionally, Social Support for PA had a correlation of r = 0.45 (p < .001) with PA Self-Efficacy. The study concluded PA Stages of Change is a significant PA predictor. Moreover, high PA Self-Efficacy indirectly helps Korean young adults to be more physically active by fostering advancement on the stages of behavioral change in PA. In contrast, Social Support for PA does not have a significant association with PA or PA Stages of Change. This non-significance of Social Support for PA can be explained with Korea's collectivistic culture. Furthermore, there is a possibility that Social Support for PA can positively affect PA by interacting with PA Self-Efficacy.

Microbial pathway for anaerobic 5'-methylthioadenosine metabolism coupled to ethylene formation.

Numerous cellular processes involving S-adenosyl-l-methionine result in the formation of the toxic by-product, 5'-methylthioadenosine (MTA). To prevent inhibitory MTA accumulation and retain biologically available sulfur, most organisms possess the "universal" methionine salvage pathway (MSP). However, the universal MSP is inherently aerobic due to a requirement of molecular oxygen for one of the key enzymes. Here, we report the presence of an exclusively anaerobic MSP that couples MTA metabolism to ethylene formation in the phototrophic bacteria Rhodospirillum rubrum and Rhodopseudomonas palustris In vivo metabolite analysis of gene deletion strains demonstrated that this anaerobic MSP functions via sequential action of MTA phosphorylase (MtnP), 5-(methylthio)ribose-1-phosphate isomerase (MtnA), and an annotated class II aldolase-like protein (Ald2) to form 2-(methylthio)acetaldehyde as an intermediate. 2-(Methylthio)acetaldehyde is reduced to 2-(methylthio)ethanol, which is further metabolized as a usable organic sulfur source, generating stoichiometric amounts of ethylene in the process. Ethylene induction experiments using 2-(methylthio)ethanol versus sulfate as sulfur sources further indicate anaerobic ethylene production from 2-(methylthio)ethanol requires protein synthesis and that this process is regulated. Finally, phylogenetic analysis reveals that the genes corresponding to these enzymes, and presumably the pathway, are widespread among anaerobic and facultatively anaerobic bacteria from soil and freshwater environments. These results not only establish the existence of a functional, exclusively anaerobic MSP, but they also suggest a possible route by which ethylene is produced by microbes in anoxic environments.

Attending to physical health in mental health services in Australia: a qualitative study of service users' experiences and expectations.

Evidence is unequivocal: the premature death of people with severe mental health problems is attributable primarily to cardiovascular disease, and healthcare provided is often suboptimal. With the overarching aim of improving outcomes, policies and guidelines oblige mental health services and psychiatrists to monitor cardio-metabolic health of patients and intervene as appropriate. Practice is highly variable; however, with ongoing debate about resourcing and responsibilities dominated by clinicians who have identified disinterest among patients as influencing practice. Seeking to balance discussion, we posed the question 'what do patients experience and expect of mental health services in relation to their physical health?' To answer it, we interviewed a convenience sample of 40 service users recruited from a mental health service in Australia, early in 2015. Data were analysed using the framework approach. With few regarding themselves as healthy, participants were commonly concerned about side effects of medication, weight and fitness but rarely mentioned tobacco smoking. Participants' accounts reinforce extensive research demonstrating variability in attention to physical health in mental health services. Reports by some participants of comprehensive care are encouraging, but widespread uncertainty about reasons for various assessments and denial of requests for management of medication side effects, including weight gain, gives cause for concern. Although participants in this study wanted to improve their health and health-related quality of life, they acknowledged that their motivation and ability to do so fluctuated with mental health. They expected clinicians to work proactively, especially when symptoms compromised capacity for self-care, and mental health services to provide or enable access to health-promoting interventions. Attention should be given, as a matter of priority, to creating conditions (culture and infrastructure) needed to support sustained attention to physical health within services and, importantly, to full engagement of service users in management of their physical health.

Development of a plasmid addicted system that is independent of co-inducers, antibiotics and specific carbon source additions for bioproduct (1-butanol) synthesis in Escherichia coli.

Synthetic biology approaches for the synthesis of value-based products provide interesting and potentially fruitful possibilities for generating a wide variety of useful compounds and biofuels. However, industrial production is hampered by the costs associated with the need to supplement large microbial cultures with expensive but necessary co-inducer compounds and antibiotics that are required for up-regulating synthetic gene expression and maintaining plasmid-borne synthetic genes, respectively. To address these issues, a metabolism-based plasmid addiction system, which relies on lipopolysaccharide biosynthesis and maintenance of cellular redox balance for 1-butanol production; and utilizes an active constitutive promoter, was developed in Escherichia coli. Expression of the plasmid is absolutely required for cell viability and 1-butanol production. This system abrogates the need for expensive antibiotics and co-inducer molecules so that plasmid-borne synthetic genes may be expressed at high levels in a cost-effective manner. To illustrate these principles, high level and sustained production of 1-butanol by E. coli was demonstrated under different growth conditions and in semi-continuous batch cultures, in the absence of antibiotics and co-inducer molecules.

Schools as a community resource for physical activity: legal considerations for decision makers.

Public schools may offer community residents access to gymnasiums, playfields, etc. When school facilities are available and/or opened up for public use in this manner, what are the legal obligations and liability concerns that arise for the schools and the users? Joint- and shared-use facilities and lands have some legal protections, which this paper introduces and reviews. Legal cases (and precedent) are shared with readers. Within this context, a model depicting factors influencing decisions to allow public use of school facilities for recreation and physical activity is introduced.