Role of PUG1 in inducible porphyrin and heme transport in Saccharomyces cerevisiae

Unlike pathogenic fungi, the budding yeast Saccharomyces cerevisiae is not efficient at using heme as a nutritional source of iron. Here we report that for this yeast, heme uptake is induced under conditions of heme starvation. Heme synthesis requires oxygen, and yeast grown anaerobically exhibited an increased uptake of hemin. Similarly, a strain lacking aminolevulinate synthase exhibited a sixfold increase in hemin uptake when grown without 2-aminolevulinic acid. We used microarray analysis of cells grown under reduced oxygen tension or reduced intracellular heme conditions to identify candidate genes involved in heme uptake. Surprisingly, overexpression of PUG1 (protoporphyrin uptake gene 1) resulted in reduced utilization of exogenous heme by a heme-deficient strain and, conversely, increased the utilization of protoporphyrin IX. Pug1p was localized to the plasma membrane by indirect immunofluorescence and subcellular fractionation. Strains overexpressing PUG1 exhibited decreased accumulation of [(55)Fe]hemin but increased accumulation of protoporphyrin IX compared to the wild-type strain. To measure the effect of PUG1 overexpression on intracellular heme pools, we used a CYC1-lacZ reporter, which is activated in the presence of heme, and we monitored the activity of a heme-containing metalloreductase, Fre1p, expressed from a constitutive promoter. The data from these experiments were consistent with a role for Pug1p in inducible protoporphyrin IX influx and heme efflux.     

Deep short-read sequencing of chromosome 17 from the mouse strains A/J and CAST/Ei identifies significant germline variation and candidate genes that regulate liver triglyceride levels

Genome sequences are essential tools for comparative and mutational analyses. Here we present the short read sequence of mouse chromosome 17 from the Mus musculus domesticus derived strain A/J, and the Mus musculus castaneus derived strain CAST/Ei. We describe approaches for the accurate identification of nucleotide and structural variation in the genomes of vertebrate experimental organisms, and show how these techniques can be applied to help prioritize candidate genes within quantitative trait loci.     

3-[6-(2-Dimethylamino-1-imidazol-1-yl-butyl)-naphthalen-2-yloxy]-2,2-dimethyl-propionic acid as a highly potent and selective retinoic acid metabolic blocking agent

3-[6-(2-Dimethylamino-1-imidazol-1-yl-butyl)-naphthalen-2-yloxy]-2,2-dimethyl-propionic acid and analogs were designed and synthesized as highly potent and selective CYP26 inhibitors, serving as retinoic acid metabolic blocking agents (RAMBAs), with demonstrated in vivo efficacy to increase the half-life of exogenous atRA.     

Transmission electron microscopy studies of Moraxella (Branhamella) catarrhalis

A trypsin-sensitive 200-kDa protein has been reported to be exclusively associated with haemagglutinating isolates of Moraxella (Branhamella) catarrhalis. Transmission electron microscopy studies revealed that haemagglutination by M. catarrhalis to both human and rabbit erythrocytes was mediated by a trypsin-sensitive outer fibrillar coat. This fibrillar layer was absent on non-haemagglutinating isolates examined. Immuno-electron microscopy, using a polyclonal antiserum containing antibodies to the 200-kDa protein as a probe, showed that the 200-kDa protein is present on the outer fibrillar layer of the bacterium. These findings suggest that the haemagglutinin of M. catarrhalis is a 200-kDa protein present on the outer fibrillar coat.     

Evaluating future success of whitebark pine ecosystem restoration under climate change using simulation modeling

Major declines of whitebark pine forests throughout western North America from the combined effects of mountain pine beetle (Dendroctonus ponderosae) outbreaks, fire exclusion policies, and the exotic disease white pine blister rust (WPBR) have spurred many restoration actions. However, projected future warming and drying may further exacerbate the species' decline and possibly compromise long‐term success of today's restoration activities. We evaluated successes of restoration treatments under future climate using a comprehensive landscape simulation experiment. The spatially explicit, ecological process model FireBGCv2 was used to simulate whitebark pine populations on two U.S. Northern Rocky Mountain landscapes over 95 years under two climate, three restoration, and two fire management scenarios. Major findings were that (1) whitebark pine can remain on some high mountain landscapes in a future climate albeit at lower basal areas (50% decrease), (2) restoration efforts, such as thinning and prescribed burning, are vital to ensure future whitebark pine forests, and (3) climate change impacts on whitebark pine vary by local setting. Whitebark pine restoration efforts will mostly be successful in the future but only if future populations are somewhat resistant to WPBR. Results were used to develop general guidelines that address climate change impacts for planning, designing, implementing, and evaluating fine‐scale restoration activities.     

Assessment of oxidant susceptibility of red blood cells in various species based on cell deformability

The present study was designed to investigate the oxidant susceptibility of red blood cells (RBC) from four species (echidna, human, koala, Tasmanian devil) based on changes in cellular deformability. These species were specifically chosen based on differences in lifestyle and/or biology associated with varied levels of oxidative stress. The major focus was the influence of superoxide radicals generated within the cell (phenazine methosulfate, PMS, 50 μM) or in the extracellular medium (xanthine oxidase-hypoxanthine, XO-HX, 0.1 U/ml XO) on RBC deformability at various shear stresses (SS). RBC deformability was assessed by laser-diffraction analysis using a "slit-flow ektacytometer". Both superoxide-generating treatments resulted in significant increases of methemoglobin for all species (p < 0.01), with Tasmanian devil RBC demonstrating the most sensitivity to either treatment. PMS caused impaired RBC deformability for all species, but vast interspecies variations were observed: human and koala cells exhibited a similar sigmoid-like response to SS, short-beaked echidna values were markedly lower and only increased slightly with SS, while Tasmanian devil RBC were extremely rigid. The effect of XO-HX on RBC deformability was less when compared with PMS (i.e., smaller increase in rigidity) with the exception of Tasmanian devil RBC which exhibited essentially no deformation even at the highest SS; Tasmanian devil RBC response to XO-HX was thus comparable to that observed with PMS. Our findings indicate that ektacytometry can be used to determine the oxidant susceptibility of RBC from different species which varies significantly among mammals representing diverse lifestyles and evolutionary histories. These differences in susceptibility are consistent with species-specific discrepancies between observed and allometrically-predicted life spans and are compatible with the oxidant theory of aging.     

Processing of Spatial-Frequency Altered Faces in Schizophrenia: Effects of Illness Phase and Duration

Low spatial frequency (SF) processing has been shown to be impaired in people with schizophrenia, but it is not clear how this varies with clinical state or illness chronicity. We compared schizophrenia patients (SCZ, n = 34), first episode psychosis patients (FEP, n = 22), and healthy controls (CON, n = 35) on a gender/facial discrimination task. Images were either unaltered (broadband spatial frequency, BSF), or had high or low SF information removed (LSF and HSF conditions, respectively). The task was performed at hospital admission and discharge for patients, and at corresponding time points for controls. Groups were matched on visual acuity. At admission, compared to their BSF performance, each group was significantly worse with low SF stimuli, and most impaired with high SF stimuli. The level of impairment at each SF did not depend on group. At discharge, the SCZ group performed more poorly in the LSF condition than the other groups, and showed the greatest degree of performance decline collapsed over HSF and LSF conditions, although the latter finding was not significant when controlling for visual acuity. Performance did not change significantly over time for any group. HSF processing was strongly related to visual acuity at both time points for all groups. We conclude the following: 1) SF processing abilities in schizophrenia are relatively stable across clinical state; 2) face processing abnormalities in SCZ are not secondary to problems processing specific SFs, but are due to other known difficulties constructing visual representations from degraded information; and 3) the relationship between HSF processing and visual acuity, along with known SCZ- and medication-related acuity reductions, and the elimination of a SCZ-related impairment after controlling for visual acuity in this study, all raise the possibility that some prior findings of impaired perception in SCZ may be secondary to acuity reductions.