Hemoglobin genotype has minimal influence on the physiological response of juvenile atlantic cod (Gadus morhua) to environmental challenges

Hemoglobin (Hb) polymorphism in cod is associated with temperature‐related differences in biogeographical distribution, and several authors have suggested that functional characteristics of the various hemoglobin isoforms (HbIs) directly influence phenotypic traits such as growth rate. However, no study has directly examined whether Hb genotype translates into physiological differences at the whole animal level. Thus, we generated a family of juvenile Atlantic cod consisting of all three main Hb genotypes (HbI‐1/1, HbI‐2/2, and HbI‐1/2) by crossing a single pair of heterozygous parents, and we compared their metabolic and cortisol responses to an acute thermal challenge (10&deg;C to their critical thermal maximum [CTM] or 22&deg;C, respectively) and tolerance of graded hypoxia. There were no differences in routine metabolism (at 10&deg;C), maximum metabolic rate, metabolic scope, CTM (overall mean 22.9&deg; &plusmn; 0.2&deg;C), or resting and poststress plasma cortisol levels among Hb genotypes. Further, although the HbI‐1/1 fish grew more (by 15%&ndash;30% during the first 9 mo) when reared at 10&deg; &plusmn; 1&deg;C and had a slightly enhanced hypoxia tolerance at 10&deg;C (e.g., the critical O2 levels for HbI‐1/1, HbI‐2/2, and HbI‐1/2 cod were 35.56% &plusmn; 1.24%, and 40.20% &plusmn; 1.99% air saturation, respectively), these results are contradictory to expectations based on HbI functional properties. Thus, our findings (1) do not support previous assumptions that growth rate differences among cod Hb genotypes result from a more efficient use of the oxygen supply&mdash;that is, reduced standard metabolic rates and/or increased metabolic capacity&mdash;and (2) suggest that in juvenile cod, there is no selective advantage to having a particular Hb genotype with regards to the capacity to withstand ecologically relevant environmental challenges.<br /

A Multinational Analysis of Mutations and Heterogeneity in PZase, RpsA, and PanD Associated with Pyrazinamide Resistance in M/XDR Mycobacterium tuberculosis.

Pyrazinamide (PZA) is an important first-line drug in all existing and new tuberculosis (TB) treatment regimens. PZA-resistance in M. tuberculosis is increasing, especially among M/XDR cases. Noted issues with PZA Drug Susceptibility Testing (DST) have driven the search for alternative tests. This study provides a comprehensive assessment of PZA molecular diagnostics in M/XDR TB cases. A set of 296, mostly XDR, clinical M. tuberculosis isolates from four countries were subjected to DST for eight drugs, confirmatory Wayne's assay, and whole-genome sequencing. Three genes implicated in PZA resistance, pncA, rpsA, and panD were investigated. Assuming all non-synonymous mutations cause resistance, we report 90% sensitivity and 65% specificity for a pncA-based molecular test. The addition of rpsA and panD potentially provides 2% increase in sensitivity. Molecular heterogeneity in pncA was associated with resistance and should be evaluated as a diagnostic tool. Mutations near the N-terminus and C-terminus of PZase were associated with East-Asian and Euro-American lineages, respectively. Finally, Euro-American isolates are most likely to have a wild-type PZase and escape molecular detection. Overall, the 8-10% resistance without markers may point to alternative mechanisms of resistance. Confirmatory mutagenesis may improve the disconcertingly low specificity but reduce sensitivity since not all mutations may cause resistance

Neighborhood social processes as moderators between racial discrimination and depressive symptoms for African American adolescents

Racial discrimination is associated with numerous psychological consequences, including increased depressive symptoms for African American adolescents (Brody et al., 2006; Wong, Eccles, & Sameroff, 2003). Adolescents’ perceptions of their neighborhood can influence how youth interpret and manage racial discrimination (Sampson, Morenoff, & Gannon‐Rowley, 2002). Yet little is known about how adolescent perceptions of neighborhood cohesion and neighborhood disorganization protect or exacerbate the effects of racial discrimination, or how these effects vary by youth’s gender. Therefore, the current study examined whether neighborhood social cohesion and neighborhood disorganization moderated the association between racial discrimination and depressive symptoms for African American adolescents and how the effects differ for boys and girls. Participants were 106 African American adolescents (57% female; mean age 15.14) from an urban metropolitan area. Regression analyses suggest that perceptions of neighborhood social cohesion protected against racial discrimination for boys and girls. Additionally, the results indicate that when boys perceive less neighborhood disorganization, racial discrimination has a greater influence on their depressive symptoms. Findings have implications for intervention and prevention efforts that enhance and utilize positive neighborhood social processes for youth contending with racial discrimination.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145257/1/jcop21970_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145257/2/jcop21970.pd

The efficacy and costs of plasma transfusion in naturally diseased horses

Hypoproteinemia secondary to gastrointestinal disease in horses has traditionally been treated with the administration of colloids such as equine plasma or hetastarch. While plasma transfusion is common, evidence-based guidelines for its use in hypoproteinemic horses are lacking. This study involved prospective and retrospective components that aimed to weigh the efficacy of plasma transfusion in treating hypoproteinemia against the risks and expense of treatment. In the retrospective portion of this study, the effects, outcome, and cost of plasma administration in horses hospitalized at the OSU VTH Large Animal Hospital between 2013 and 2018 were evaluated (n = 91). Transfusion resulted in minor but statistically significant changes from baseline in several clinically relevant blood variables. The rate of survival to discharge of transfused horses was 47.6% and the incidence of transfusion reactions was 28%. The average cost of transfusion was $825 ± 507.07. In the prospective portion of this study, the effect of plasma transfusion on colloid osmotic pressure (COP), total plasma protein, and albumin concentrations in ten naturally diseased adult horses was evaluated over time and produced significant but minor increases from baseline in studied variables for 8 hours following transfusion. In conclusion, plasma transfusion in diseased horses attracts considerable expense, is associated with certain risks, and has limited impact on the variables it is meant to influence. These findings suggest consideration should be given to discontinuing this practice for the treatment of hypoproteinemia in diseased horses

Time-Dependent Mechanical Behavior of Proton Exchange Membrane Fuel Cell Electrodes

The electrodes used for Proton Exchange Membrane Fuel Cells (PEMFCs) are typically painted or sprayed onto the membrane during manufacturing, making it difficult to directly characterize their mechanical behavior as a stand-alone material. An experimental-numerical hybrid technique is devised to extract the electrode properties from the experimentally measured properties of Nafion® 211 membrane1 and a membrane electrode assembly (MEA) based on Nafion® 211 membrane at various temperatures, humidities, and strain rates. Within the linear regime, the rule-of-mixtures assuming an iso-strain condition is used to calculate the rate-dependent Young\u27s modulus of the electrodes. Beyond the linear regime, reverse analysis is conducted using finite element models of the MEA to determine the non-linear behavior of the electrodes. The mechanical damage mechanisms that occur in the MEA during tensile loading are also investigated through interrupted tension tests and then incorporated into the finite element models for determining the electrode behavior. The results suggest that the electrodes have similar behavior to Nafion® 211 membrane as functions of strain rate, temperature and humidity, but with lower Young\u27s modulus and proportional limit

Time-Dependent Mechanical Behavior of Proton Exchange Membrane Fuel Cell Electrodes

The electrodes used for Proton Exchange Membrane Fuel Cells (PEMFCs) are typically painted or sprayed onto the membrane during manufacturing, making it difficult to directly characterize their mechanical behavior as a stand-alone material. An experimental-numerical hybrid technique is devised to extract the electrode properties from the experimentally measured properties of Nafion® 211 membrane1 and a membrane electrode assembly (MEA) based on Nafion® 211 membrane at various temperatures, humidities, and strain rates. Within the linear regime, the rule-of-mixtures assuming an iso-strain condition is used to calculate the rate-dependent Young\u27s modulus of the electrodes. Beyond the linear regime, reverse analysis is conducted using finite element models of the MEA to determine the non-linear behavior of the electrodes. The mechanical damage mechanisms that occur in the MEA during tensile loading are also investigated through interrupted tension tests and then incorporated into the finite element models for determining the electrode behavior. The results suggest that the electrodes have similar behavior to Nafion® 211 membrane as functions of strain rate, temperature and humidity, but with lower Young\u27s modulus and proportional limit

Exploitation of the Escherichia coli lac operon promoter for controlled recombinant protein production

The Escherichia coli lac operon promoter is widely used as a tool to control recombinant protein production in bacteria. Here we give a brief review of how it functions, how it is regulated, and how, based on this knowledge, a suite of lac promoter derivatives has been developed to give controlled expression that is suitable for diverse biotechnology applications