Does shelter influence the metabolic traits of a teleost fish?

Availability of shelter is an important component of habitat selection for animals as it can influence survival (protection against harsh physical conditions and predation) and growth (energy acquisition and expenditure). Few studies address the effect of shelter on metabolic expenditures associated with non-mechanical tasks (excluding station holding or movement). The main goal of this study was to investigate the influence of shelter use on metabolic traits of smallmouth bass (Micropterus dolomieu) from two populations (Kiamika River and Lake Long). Respirometry experiments on smallmouth bass were conducted to measure standard metabolic rate (SMR), resting metabolic rate (RMR), aerobic scope (AS), recovery time (RT) and excess post-exercise oxygen consumption (EPOC) in the presence or absence of shelter. The presence of shelter did not affect most metabolic traits, except for RMR, which was reduced in the presence of shelter for Lake Long fish. The results of this study also show that larger fish had lower SMR in the presence of shelter than when it was absent. When accounting for social hierarchy, there were no differences in most metabolic traits in dominant or subordinate fish in the presence or absence of shelter, except for RT, which was significantly lower in the presence of shelter for dominant fish. These results do not support the existence of an unequivocal relationship between individual metabolic traits and the presence of shelter. If physiological motives may influence the use of shelter, sheltering in itself might not have important consequences on energy expenditures required for non-mechanical tasks.     

Expanding Disease Definitions in Guidelines and Expert Panel Ties to Industry: A Cross-sectional Study of Common Conditions in the United States

Background

Financial ties between health professionals and industry may unduly influence professional judgments and some researchers have suggested that widening disease definitions may be one driver of over-diagnosis, bringing potentially unnecessary labeling and harm. We aimed to identify guidelines in which disease definitions were changed, to assess whether any proposed changes would increase the numbers of individuals considered to have the disease, whether potential harms of expanding disease definitions were investigated, and the extent of members'' industry ties.

Methods and Findings

We undertook a cross-sectional study of the most recent publication between 2000 and 2013 from national and international guideline panels making decisions about definitions or diagnostic criteria for common conditions in the United States. We assessed whether proposed changes widened or narrowed disease definitions, rationales offered, mention of potential harms of those changes, and the nature and extent of disclosed ties between members and pharmaceutical or device companies.Of 16 publications on 14 common conditions, ten proposed changes widening and one narrowing definitions. For five, impact was unclear. Widening fell into three categories: creating “pre-disease”; lowering diagnostic thresholds; and proposing earlier or different diagnostic methods. Rationales included standardising diagnostic criteria and new evidence about risks for people previously considered to not have the disease. No publication included rigorous assessment of potential harms of proposed changes.Among 14 panels with disclosures, the average proportion of members with industry ties was 75%. Twelve were chaired by people with ties. For members with ties, the median number of companies to which they had ties was seven. Companies with ties to the highest proportions of members were active in the relevant therapeutic area. Limitations arise from reliance on only disclosed ties, and exclusion of conditions too broad to enable analysis of single panel publications.

Conclusions

For the common conditions studied, a majority of panels proposed changes to disease definitions that increased the number of individuals considered to have the disease, none reported rigorous assessment of potential harms of that widening, and most had a majority of members disclosing financial ties to pharmaceutical companies. Please see later in the article for the Editors'' Summary     

Biocontrol agents promote growth of potato pathogens,depending on environmental conditions

There is a pressing need to understand and optimize biological control so as to avoid over‐reliance on the synthetic chemical pesticides that can damage environmental and human health. This study focused on interactions between a novel biocontrol‐strain, Bacillus sp. JC12GB43, and potato‐pathogenic Phytophthora and Fusarium species. In assays carried out in vitro and on the potato tuber, the bacterium was capable of near‐complete inhibition of pathogens. This Bacillus was sufficiently xerotolerant (water activity limit for growth = 0.928) to out‐perform Phytophthora infestans (~0.960) and challenge Fusarium coeruleum (~0.847) and Fusarium sambucinum (~0.860) towards the lower limits of their growth windows. Under some conditions, however, strain JC12GB43 stimulated proliferation of the pathogens: for instance, Fusarium coeruleum growth‐rate was increased under chaotropic conditions in vitro (132 mM urea) by >100% and on tubers (2‐M glycerol) by up to 570%. Culture‐based assays involving macromolecule‐stabilizing (kosmotropic) compatible solutes provided proof‐of‐principle that the Bacillus may provide kosmotropic metabolites to the plant pathogen under conditions that destabilize macromolecular systems of the fungal cell. Whilst unprecedented, this finding is consistent with earlier reports that fungi can utilize metabolites derived from bacterial cells. Unless the antimicrobial activities of candidate biocontrol strains are assayed over a full range of field‐relevant parameters, biocontrol agents may promote plant pathogen infections and thereby reduce crop yields. These findings indicate that biocontrol activity, therefore, ought to be regarded as a mode‐of‐behaviour (dependent on prevailing conditions) rather than an inherent property of a bacterial strain.     

Inhibition of Phosphoinositide 3-Kinase p110delta Does Not Affect T Cell Driven Development of Type 1 Diabetes Despite Significant Effects on Cytokine Production

Type 1 diabetes is caused by the destruction of insulin producing beta cells by the immune system. The p110δ isoform of PI3K is expressed primarily in cells of haematopoietic origin and the catalytic activity of p110δ is important for the activation of these cells. Targeting of this pathway offers an opportunity to reduce immune cell activity without unwanted side effects. We have explored the effects of a specific p110δ isoform inhibitor, IC87114, on diabetogenic T cells both in vitro and in vivo, and find that although pharmacological inhibition of p110δ has a considerable impact on the production of pro-inflammatory cytokines, it does not delay the onset of diabetes after adoptive transfer of diabetogenic cells. Further, we demonstrate that combination treatment with CTLA4-Ig does not improve the efficacy of treatment, but instead attenuates the protective effects seen with CTLA4-Ig treatment alone. Our results suggest that decreased IL-10 production by Foxp3⁺ CD4⁺ T cells in the presence of IC87114 negates individual anti-inflammatory effects of IC8114 and CTLA4-Ig.     

Coloured LED light as a potential behavioural guidance tool for age 0 and 2 year walleye Sander vitreus

Based on existing laboratory research on the visual physiology of walleye Sander vitreus, we tested colours of known spectral sensitivity (i.e., green and orange) using constant and strobing (5 Hz) illumination with an LED-based light guidance device (LGD). Hatchery-reared age 0 and 2 years S. vitreus were exposed to these four light combinations as well as an unilluminated control treatment during day and night trials. Age 2 years S. vitreus generally avoided the LGD when light was produced (negative phototaxis) compared with the control, with continuous illumination having a greater effect than strobing. The proportions of both age 0 and 2 year fish exiting illuminating zones of the trial arena did not differ with light colour or strobe rate, suggesting that phototactic behaviours in S. vitreus do not change with ontogeny in these age classes. Our findings confirm that typical behavioural responses of S. vitreus to light stimuli are characterised by avoidance and provide evidence that the use of light for behavioural guidance (deterrence) may be effective at reducing entrainment and impingement of this species on hydraulic barriers during migrations, independent of ontogenetic stage.     

Influence of light on natural indigo production from woad (Isatis tinctoria)

In woad (Isatis tinctoria), field observations indicated, that after periods of dry sunny weather, indigo yields increased significantly, suggesting that light intensity and quality affected indigo precursor production. Therefore, woad was grown under different light intensities and in the presence or absence of supplementary UV light. In general, plants supplied with more light produced more indigo than those given lesser light. When plants under greater light regimes were transferred to lesser light conditions, then indigo production declined. The opposite was also true, indicating that greater indigo production can be obtained from plants harvested after periods of increased sunlight.     

Effects of Abnormal-Sterol Accumulation on Ustilago maydis Plasma Membrane H+-ATPase Stoichiometry and Polypeptide Pattern

Accumulation of 14α-methylated sterols or Δ⁸-sterols in Ustilago maydis affected three aspects of the plasma membrane H⁺-ATPase. Proton transport was reduced in Δ⁸-sterol-accumulating samples, due to an altered H⁺/ATP stoichiometry. ATP hydrolytic activity was increased, but no direct correlation with the extent or type of abnormal sterol accumulated could be drawn. Finally, Western blot analysis with antibodies against yeast PMA1 revealed a second lighter band (99-kDa band) in all samples from abnormal-sterol-accumulating sporidia. The conclusions are that the 99-kDa band and a reduced stoichiometry are directly linked to the presence of abnormal sterols, while changes in hydrolytic activity are linked only indirectly.     

Vascular adaptations to pregnancy in mice: effects on myogenic tone

The mechanisms underlying vascular adaptations in pregnancy remain to be fully elucidated. One of the contributory mechanisms for reduced vascular tone may be a reduction of myogenic tone. Myogenic tone was assessed as the difference between internal diameter in the presence and absence of external calcium at different intramural pressure steps (60-100 mmHg). Myogenic responses were reduced in resistance-sized mesenteric and main uterine arteries in late pregnant compared with nonpregnant C57BL/6J mice. In vessels from pregnant, but not nonpregnant mice, the myogenic response was enhanced by preincubation with nitric oxide (NO) synthase inhibitor N(G)-nitro-l-arginine methyl ester, was further elevated by the gap junction inhibitor 18-alpha glycyrrhetinic acid, but was unaltered by the prostaglandin H synthase inhibitor meclofenamate. Endothelium removal enhanced myogenic tone only in the vessels from pregnant animals, thus confirming the role of the endothelium in modulating myogenic tone in pregnancy. These results suggest that endothelium-derived NO as well as gap junction communications modulate myogenic tone in mouse pregnancy.