Effects of a transition from normoxia to anoxia on yeast cytochrome c oxidase and the mitochondrial respiratory chain Implications for hypoxic gene induction

AbstractPrevious studies have demonstrated that the mitochondrial respiratory chain and cytochrome c oxidase participate in oxygen sensing and the induction of some hypoxic nuclear genes in eukaryotes. In addition, it has been proposed that mitochondrially-generated reactive oxygen and nitrogen species function as signals in a signaling pathway for the induction of hypoxic genes. To gain insight concerning this pathway, we have looked at changes in the functionality of the yeast respiratory chain as cells experience a shift from normoxia to anoxia. These studies have revealed that yeast cells retain the ability to respire at normoxic levels for up to 4 h after a shift and that the mitochondrial cytochrome levels drop rapidly to 30–50% of their normoxic levels and the turnover rate of cytochrome c oxidase (COX) increases during this shift. The increase in COX turnover rate cannot be explained by replacing the aerobic isoform, Va, of cytochrome c oxidase subunit V with the more active hypoxic isoform, Vb. We have also found that mitochondria retain the ability to respire, albeit at reduced levels, in anoxic cells, indicating that yeast cells maintain a functional mitochondrial respiratory chain in the absence of oxygen. This raises the intriguing possibility that the mitochondrial respiratory chain has a previously unexplored role in anoxic cells and may function with an alternative electron acceptor when oxygen is unavailable

Intracellular localization and interaction of mRNA binding proteins as detected by FRET

<p>Abstract</p> <p>Background</p> <p>A number of RNA binding proteins (BPs) bind to A+U rich elements (AREs), commonly present within 3'UTRs of highly regulated RNAs. Individual RNA-BPs proteins can modulate RNA stability, RNA localization, and/or translational efficiency. Although biochemical studies have demonstrated selectivity of ARE-BPs for individual RNAs, less certain is the <it>in vivo </it>composition of RNA-BP multiprotein complexes and how their composition is affected by signaling events and intracellular localization. Using FRET, we previously demonstrated that two ARE-BPs, HuR and AUF1, form stable homomeric and heteromeric associations in the nucleus and cytoplasm. In the current study, we use immuno-FRET of endogenous proteins to examine the intracellular localization and interactions of HuR and AUF1 as well as KSRP, TIA-1, and Hedls. These results were compared to those obtained with their exogenously expressed, fluorescently labeled counterparts.</p> <p>Results</p> <p>All ARE-BPs examined were found to colocalize and to form stable associations with selected other RNA-BPs in one or more cellular locations variably including the nucleus, cytoplasm (in general), or in stress granules or P bodies. Interestingly, FRET based interaction of the translational suppressor, TIA-1, and the decapping protein, Hedls, was found to occur at the interface of stress granules and P bodies, dynamic sites of intracellular RNA storage and/or turnover. To explore the physical interactions of RNA-BPs with ARE containing RNAs, <it>in vitro </it>transcribed Cy3-labeled RNA was transfected into cells. Interestingly, Cy3-RNA was found to coalesce in P body like punctate structures and, by FRET, was found to interact with the RNA decapping proteins, Hedls and Dcp1.</p> <p>Conclusions</p> <p>Biochemical methodologies, such as co-immunoprecipitation, and cell biological approaches such as standard confocal microscopy are useful in demonstrating the possibility of proteins and/or proteins and RNAs interacting. However, as demonstrated herein, colocalization of proteins and proteins and RNA is not always indicative of interaction. To this point, using FRET and immuno-FRET, we have demonstrated that RNA-BPs can visually colocalize without producing a FRET signal. In contrast, proteins that appear to be delimited to one or another intracellular compartment can be shown to interact when those compartments are juxtaposed.</p

Associations of blood pressure with body composition among Afro-Caribbean children in Barbados

Despite complex presentation of adult hypertension and a concomitant obesity epidemic, little is known about overweight in relation to blood pressure among Caribbean children. We examined blood pressure in relation to body size in a cross-sectional study of 573 Barbadian children aged 9–10 years (2010-2011).The United States normative blood pressure percentiles were used to identify children with high (≥ 95th percentile) or high normal blood pressure (90th – 95th percentile). The World Health Organization body mass index cut-off points were used to assess weight status. Major findings: Thirty percent of children were overweight/obese. Percentage fat mass differed between girls (20.4%) and boys (17.72%) (p&#60; 0.05). Mean systolic blood pressure among girls was 106.11 (95% CI 105.05, 107.17) mmHg and 105.23 (104.09, 106.38) for boys. The percentages with high or high-normal mean systolic blood pressurewere14.38% (10.47, 18.29) for girls and 8.08% (4.74, 11.41) for boys. Height and body mass index were independent correlates of systolic and diastolic blood pressure. Mean systolic blood pressure was related to lean mass but not fat mass, while diastolic blood pressure was associated with fat mass index and overweight. Principal conclusion: One third of 9-10 year old children in Barbados were overweight/obese and 12% had elevated mean systolic blood pressure. BP was related to body size. These findings signal potential adverse trends in weight gain and BP trends for children growing up in the context of a country that has recently undergone rapid economic transition

Dietary n-3-polyunsaturated fatty acids and energy balance in overweight or moderately obese men and women: a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Dietary n-3-polyunsaturated fatty acids (n-3-PUFA) have been shown to reduce body weight and fat mass in rodents as well as in humans in one small short-term study. We conducted this controlled randomized dietary trial to test the hypothesis that n-3-PUFA lower body weight and fat mass by reducing appetite and <it>ad libitum </it>food intake and/or by increasing energy expenditure.</p> <p>Methods</p> <p>Twenty-six overweight or moderately obese (body mass index 28–33 kg/m²) men and women were included, and received either a diet rich in n-3-PUFA from both plant and marine sources or a control diet. Diets were administered in an isocaloric fashion for 2 weeks followed by 12 weeks of <it>ad libitum </it>intake. The n-3-PUFA and control diets were identical in all regards except for the fatty acid composition. All foods were provided to subjects, and leftovers were weighed back to assess actual food intake accurately for each day of the study. This design gave us 80% power to detect a difference in weight change between the n-3-PUFA and control diet groups of 2.25 kg at an α-error level of 5%.</p> <p>Results</p> <p>Both groups lost similar amounts of weight when these diets were consumed <it>ad libitum </it>for 12 weeks [mean (SD): -3.5 (3.7) kg in the control group vs. -2.8 (3.7) kg in the n-3-PUFA group, F_(1,24)= 13.425, p = 0.001 for time effect; F_(1,24)= 0.385, p = 0.541 for time × group interaction]. Consistent with this finding, we also found no differences between the n-3-PUFA and control groups with regard to appetite as measured by visual analogue scale, <it>ad libitum </it>food intake, resting energy expenditure as measured by indirect calorimetry, diurnal plasma leptin concentrations, or fasting ghrelin concentrations.</p> <p>Conclusion</p> <p>Our results suggest that dietary n-3-PUFA do not play an important role in the regulation of food intake, energy expenditure, or body weight in humans.</p

Microbial iron management mechanisms in extremely acidic environments: comparative genomics evidence for diversity and versatility

<p>Abstract</p> <p>Background</p> <p>Iron is an essential nutrient but can be toxic at high intracellular concentrations and organisms have evolved tightly regulated mechanisms for iron uptake and homeostasis. Information on iron management mechanisms is available for organisms living at circumneutral pH. However, very little is known about how acidophilic bacteria, especially those used for industrial copper bioleaching, cope with environmental iron loads that can be 10¹⁸times the concentration found in pH neutral environments. This study was motivated by the need to fill this lacuna in knowledge. An understanding of how microorganisms thrive in acidic ecosystems with high iron loads requires a comprehensive investigation of the strategies to acquire iron and to coordinate this acquisition with utilization, storage and oxidation of iron through metal responsive regulation. <it>In silico </it>prediction of iron management genes and Fur regulation was carried out for three Acidithiobacilli: <it>Acidithiobacillus ferrooxidans </it>(iron and sulfur oxidizer) <it>A. thiooxidans </it>and <it>A. caldus </it>(sulfur oxidizers) that can live between pH 1 and pH 5 and for three strict iron oxidizers of the <it>Leptospirillum </it>genus that live at pH 1 or below.</p> <p>Results</p> <p>Acidithiobacilli have predicted FeoB-like Fe(II) and Nramp-like Fe(II)-Mn(II) transporters. They also have 14 different TonB dependent ferri-siderophore transporters of diverse siderophore affinity, although they do not produce classical siderophores. Instead they have predicted novel mechanisms for dicitrate synthesis and possibly also for phosphate-chelation mediated iron uptake. It is hypothesized that the unexpectedly large number and diversity of Fe(III)-uptake systems confers versatility to this group of acidophiles, especially in higher pH environments (pH 4–5) where soluble iron may not be abundant. In contrast, Leptospirilla have only a FtrI-Fet3P-like permease and three TonB dependent ferri-dicitrate siderophore systems. This paucity of iron uptake systems could reflect their obligatory occupation of extremely low pH environments where high concentrations of soluble iron may always be available and were oxidized sulfur species might not compromise iron speciation dynamics. Presence of bacterioferritin in the Acidithiobacilli, polyphosphate accumulation functions and variants of FieF-like diffusion facilitators in both Acidithiobacilli and Leptospirilla, indicate that they may remove or store iron under conditions of variable availability. In addition, the Fe(II)-oxidizing capacity of both <it>A. ferrooxidans </it>and Leptospirilla could itself be a way to evade iron stress imposed by readily available Fe(II) ions at low pH. Fur regulatory sites have been predicted for a number of gene clusters including iron related and non-iron related functions in both the Acidithiobacilli and Leptospirilla, laying the foundation for the future discovery of iron regulated and iron-phosphate coordinated regulatory control circuits.</p> <p>Conclusion</p> <p><it>In silico </it>analyses of the genomes of acidophilic bacteria are beginning to tease apart the mechanisms that mediate iron uptake and homeostasis in low pH environments. Initial models pinpoint significant differences in abundance and diversity of iron management mechanisms between Leptospirilla and Acidithiobacilli, and begin to reveal how these two groups respond to iron cycling and iron fluctuations in naturally acidic environments and in industrial operations. Niche partitions and ecological successions between acidophilic microorganisms may be partially explained by these observed differences. Models derived from these analyses pave the way for improved hypothesis testing and well directed experimental investigation. In addition, aspects of these models should challenge investigators to evaluate alternative iron management strategies in non-acidophilic model organisms.</p

Service-Learning in the Context of Asian American Studies and the AAARCC at Purdue University: Asian/American Business Owners in Greater Lafayette and Indiana

The journey of Asian Americans in the United States is vital to understanding the perspective that Asian immigrants take on the way to becoming Asian Americans. Within the past century, Asians in America have played an essential role in communities across the country. In order to understand the efforts it takes for some of these people, our “Internship in Asian American Studies” (ASAM 490) class explored their experiences and lives by highlighting Asian American and Asian business owners in Greater Lafayette, other areas in Indiana. With a lack of vocalization about this topic, it is crucial to establish this voice for the Asian and Asian American communities. In our service-learning project, we created a narrative over images captured to visualize the history of the Asian Americans we interviewed. Through this narrative, we hope to enable a more established engagement within our campus archives both institutionally and academically in order to showcase the Asian American community and the successes and triumphs that those in the Greater Lafayette area have overcome

Evolutionary biology for the 21st century

New theoretical and conceptual frameworks are required for evolutionary biology to capitalize on the wealth of data now becoming available from the study of genomes, phenotypes, and organisms - including humans - in their natural environments.Molecular and Cellular BiologyOrganismic and Evolutionary Biolog

Computational fluid dynamics as surgical planning tool: a pilot study on middle turbinate resection.

Controversies exist regarding the resection or preservation of the middle turbinate (MT) during functional endoscopic sinus surgery. Any MT resection will perturb nasal airflow and may affect the mucociliary dynamics of the osteomeatal complex. Neither rhinometry nor computed tomography (CT) can adequately quantify nasal airflow pattern changes following surgery. This study explores the feasibility of assessing changes in nasal airflow dynamics following partial MT resection using computational fluid dynamics (CFD) techniques. We retrospectively converted the pre- and postoperative CT scans of a patient who underwent isolated partial MT concha bullosa resection into anatomically accurate three-dimensional numerical nasal models. Pre- and postsurgery nasal airflow simulations showed that the partial MT resection resulted in a shift of regional airflow towards the area of MT removal with a resultant decreased airflow velocity, decreased wall shear stress and increased local air pressure. However, the resection did not strongly affect the overall nasal airflow patterns, flow distributions in other areas of the nose, nor the odorant uptake rate to the olfactory cleft mucosa. Moreover, CFD predicted the patient\u27s failure to perceive an improvement in his unilateral nasal obstruction following surgery. Accordingly, CFD techniques can be used to predict changes in nasal airflow dynamics following partial MT resection. However, the functional implications of this analysis await further clinical studies. Nevertheless, such techniques may potentially provide a quantitative evaluation of surgical effectiveness and may prove useful in preoperatively modeling the effects of surgical interventions

Characterization of Ichthyoplankton in the Northeastern Gulf of Mexico from Seamap Plankton Surveys, 1982-1999

Data for 61 selected ichthyoplankton taxa from 1,166 bongo and neuston net samples at 72 stations comprising the USGS Northeastern Gulf of Mexico Ichthyoplankton Synopsis (UNIS) study area were analyzed. These data were taken during annual spring and fall Southeast Area Monitoring and Assessment Program (SEAMAP) Gulfwide plankton surveys over the period 1982-1999. The UNIS study area contributed disproportionately more fish eggs, total larvae and net-caught zooplankton biomass to survey totals than would be expected from the number of samples taken in the study area. This pattern was more evident during spring than fall surveys and is probably related to the close proximity of UNIS study area stations to the Mississippi River and the inshore penetration of nutrient rich deep slope water via the DeSoto Canyon. Statistical comparison of the percent frequency of occurrence of the 61 selected taxa revealed that the larvae of many were taken significantly more often in the UNIS study area than expected based on their occurrence Gulfwide. Thirteen of these taxa were taken more often in the study area during the season and collecting gear combination that accounted for the highest catches. These taxa represented fishes from mesopelagic, continental shelf, and reef assemblages reflecting the wide diversity of habitats available in the northeastern Gulf of Mexico. Distinct distribution patterns were observed among larvae in the UNIS study area that appear to be associated with the presence of the DeSoto Canyon. The consistent presence of fish eggs throughout the UNIS study area at mean abundances exceeding 100 eggs under 10 m² sea surface indicates that this region of the Gulf of Mexico is an important spawning area

When innovation outpaces regulations:The legal challenges for direct-to-patient supply of investigational medicinal products

AIMS: We profile the lack of specific regulation for direct‐to‐patient postal supply (DTP) of clinical trial medications (investigational medicinal products, IMPs) calling for increased efficiency of patient‐centred multi‐country remote clinical trials. METHODS: Questionnaires emailed to 28 European Economic Area (EEA) Medical Product Licensing Authorities (MPLAs) and Swissmedic MPLA were analysed in 2019/2020. The questionnaire asked whether DTP of IMPs was legal, followed by comparative legal analysis profiling relevant national civil and criminal liability provisions in 30 European jurisdictions (including The Netherlands), finally summarising accessible COVID‐19‐related guidance in searches of 30 official MPLA websites in January 2021. RESULTS: Twenty MPLAs responded. Twelve consented to response publication in 2021. DTP was not widely authorised, though different phrases were used to explain this. Our legal review of national laws in 29 EEA jurisdictions and Switzerland did not identify any specific sanctions for DTP of IMPs; however, we identified potential national civil and criminal liability provisions. Switzerland provides legal clarity where DTP of IMPs is conditionally legal. MPLA webpage searches for COVID‐19 guidance noted conditional acceptance by 19 MPLAs. CONCLUSIONS: Specific national legislation authorising DTP of IMPs, defining IMP categories, and conditions permitting the postage and delivery by courier in an EEA‐wide clinical trial, would support innovative patient‐centred research for multi‐country remote clinical trials. Despite it appearing more acceptable to do this between EU Member States, provided each EU MPLA and ethics board authorises it, temporary Covid‐19 restrictions in national Good Clinical Practice (GCP) guidance discourages innovative research into the safety and effectiveness of clinical trial medications