A physiological approach to quantifying thermal habitat quality for Redband Rainbow Trout (<Emphasis Type="Italic">Oncorhynchus mykiss gairdneri)</Emphasis> in the south Fork John Day River,Oregon

We examined tissue-specific levels of heat shock protein 70 (hsp70) and whole body lipid levels in juvenile redband trout (Oncorhynchus mykiss gairdneri) from the South Fork of the John Day River (SFJD), Oregon, with the goal of determining if these measures could be used as physiological indicators of thermal habitat quality for juvenile redband trout. Our objectives were to determine the hsp70 induction temperature in liver, fin, and white muscle tissue and characterize the relation between whole body lipids and hsp70 for fish in the SFJD. We found significant increases in hsp70 levels between 19 and 22°C in fin, liver, and white muscle tissue. Maximum hsp70 levels in liver, fin, and white muscle tissue occurred when mean weekly maximum temperatures (MWMT) exceeded 20–22°C. In general, the estimated hsp70 induction temperature for fin and white muscle tissue was higher than liver tissue. Whole body lipid levels began to decrease when MWMT exceeded 20.4°C. There was a significant interaction between temperature and hsp70 in fin and white muscle tissue, but not liver tissue. Collectively, these results suggest that increased hsp70 levels in juvenile redband trout are symptomatic of thermal stress, and that energy storage capacity decreases with this stress. The possible decrease in growth potential and fitness for thermally stressed individuals emphasizes the physiological justification for thermal management criteria in salmon-bearing streams.     

Pyrenoidal sequestration of cadmium impairs carbon dioxide fixation in a microalga

Mixotrophic microorganisms are able to use organic carbon as well as inorganic carbon sources and thus, play an essential role in the biogeochemical carbon cycle. In aquatic ecosystems, the alteration of carbon dioxide (CO₂) fixation by toxic metals such as cadmium – classified as a priority pollutant – could contribute to the unbalance of the carbon cycle. In consequence, the investigation of cadmium impact on carbon assimilation in mixotrophic microorganisms is of high interest. We exposed the mixotrophic microalga Chlamydomonas reinhardtii to cadmium in a growth medium containing both CO₂ and labelled ¹³C-[1,2] acetate as carbon sources. We showed that the accumulation of cadmium in the pyrenoid, where it was predominantly bound to sulphur ligands, impaired CO₂ fixation to the benefit of acetate assimilation. Transmission electron microscopy (TEM)/X-ray energy dispersive spectroscopy (X-EDS) and micro X-ray fluorescence (μXRF)/micro X-ray absorption near-edge structure (μXANES) at Cd L_III-edge indicated the localization and the speciation of cadmium in the cellular structure. In addition, nanoscale secondary ion mass spectrometry (NanoSIMS) analysis of the ¹³C/¹²C ratio in pyrenoid and starch granules revealed the origin of carbon sources. The fraction of carbon in starch originating from CO₂ decreased from 73 to 39% during cadmium stress. For the first time, the complementary use of high-resolution elemental and isotopic imaging techniques allowed relating the impact of cadmium at the subcellular level with carbon assimilation in a mixotrophic microalga.     

Glutathione-S-transferase P1 is a critical regulator of Cdk5 kinase activity

Cyclin dependent kinase-5 (Cdk5) activity is deregulated in Alzheimer's disease (AD) and contributes to all three hallmarks: neurotoxic β-amyloid formation, neurofibrillary tangles, and neuronal death. However, the mechanism leading to Cdk5 deregulation remains controversial. Cdk5 deregulation in AD is usually linked to the formation of p25, a proteolysis product of Cdk5 activator p35, which leads to Cdk5 mislocalization and hyperactivation. A few studies have indeed shown increased p25 levels in AD brains; however, others have refuted this observation. These contradictory findings suggest that additional factors contribute to Cdk5 deregulation. This study identified glutathione-S-transferase pi 1 (GSTP1) as a novel Cdk5 regulatory protein. We demonstrate that it is a critical determinant of Cdk5 activity in human AD brains and various cancer and neuronal cells. Increased GSTP1 levels were consistently associated with reduced Cdk5 activity. GSTP1 directly inhibits Cdk5 by dislodging p25/p35, and indirectly by eliminating oxidative stress. Cdk5 promotes and is activated by oxidative stress, thereby engaging a feedback loop which ultimately leads to cell death. Not surprisingly, GSTP1 transduction conferred a high degree of neuroprotection under neurotoxic conditions. Given the critical role of oxidative stress in AD pathogenesis, an increase in GSTP1 level may be an alternative way to modulate Cdk5 signaling, eliminate oxidative stress, and prevent neurodegeneration.     

The long-term effect of partial defoliation on the yield of short-rotation coppice willow

Five varieties of willow were planted in a randomised block design at the Northern Ireland Horticulture and Plant Breeding Station, Loughgall, County Armagh in 1997. Three treatments were applied: control (no treatment), manual defoliation and routine control (spraying) of willow beetles. The defoliation was carried out at 75% for the first 2 years and thereafter 25% up to the first harvest in January 2001. During the second production cycle, no manual defoliation was applied in order to observe the ability of the different varieties to recover from earlier damage. The variety 78112 exhibited the highest yield loss in the first cycle as a result of defoliation (～70%), while the vigorous variety Tora suffered least yield loss (35–43%). In the recovery phase (second production cycle 2001–2003), all the varieties showed little improvement in yields in plots that had been defoliated previously, indicating a long‐term legacy of yield loss as a result of defoliation. The possible reasons for this inability to recover are discussed.     

Handbook of Bioinspired Algorithms and Applications * Edited by Stephan Olariu and Albert Y.

The ‘Handbook of Bioinspired Algorithms and Applications’is a unifying compilation of chapters that discuss bioinspiredalgorithms. These are algorithms that have been conceived usingcues from nature, such as, evolution, insect swarming, foodforaging and brain neurons. The book presents a broad rangeof solved problems and cases studied using bioinspired paradigms.The book is well organized, each chapter being condensed butdetailed     

De novo design and evolution of artificial disulfide isomerase enzymes analogous to the bacterial DsbC

The Escherichia coli disulfide isomerase, DsbC is a V-shaped homodimer with each monomer comprising a dimerization region that forms part of a putative peptide-binding pocket and a thioredoxin catalytic domain. Disulfide isomerases from prokaryotes and eukaryotes exhibit little sequence homology but display very similar structural organization with two thioredoxin domains facing each other on top of the dimerization/peptide-binding region. To aid the understanding of the mechanistic significance of thioredoxin domain dimerization and of the peptide-binding cleft of DsbC, we constructed a series of protein chimeras comprising unrelated protein dimerization domains fused to thioredoxin superfamily enzymes. Chimeras consisting of the dimerization domain and the alpha-helical linker of the bacterial proline cis/trans isomerase FkpA and the periplasmic oxidase DsbA gave rise to enzymes that catalyzed the folding of multidisulfide substrate proteins in vivo with comparable efficiency to E. coli DsbC. In addition, expression of FkpA-DsbAs conferred modest resistance to CuCl2, a phenotype that depends on disulfide bond isomerization. Selection for resistance to elevated CuCl2 concentrations led to the isolation of FkpA-DsbA mutants containing a single amino acid substitution that changed the active site of the DsbA domain from CPHC into CPYC, increasing the similarity to the DsbC active site (CGYC). Unlike DsbC, which is resistant to oxidation by DsbB-DsbA and does not normally catalyze disulfide bond formation under physiological conditions, the FkpA-DsbA chimeras functioned both as oxidases and isomerases. The engineering of these efficient artificial isomerases delineates the key features of catalysis of disulfide bond isomerization and enhances our understanding of its evolution.     

Dibasic benzo[b]thiophene derivatives as a novel class of active site directed thrombin inhibitors: 2. Sidechain optimization and demonstration of in vivo efficacy

Potent, subnanomolar thrombin inhibitors 4, 5, and 6 are developed through side chain optimization of novel, benzo[b]thiophene-based small organic entities 2 and 3 and through SAR additivity studies of the new structural elements identified. X-ray crystallographic studies of 4b-thrombin complex revealed a hydrophobic and an electrostatic interaction of these new elements with thrombin at the S2 and S3 binding sites. In vitro and in vivo pharmacological studies showed that 4, 5, and 6 are potent anticoagulants in human plasma with demonstrated antithrombotic efficacy in a rat model of thrombosis.     

Association of a bovine prion gene haplotype with atypical BSE

Background

Atypical bovine spongiform encephalopathies (BSEs) are recently recognized prion diseases of cattle. Atypical BSEs are rare; approximately 30 cases have been identified worldwide. We tested prion gene (PRNP) haplotypes for an association with atypical BSE.

Methodology/Principle Findings

Haplotype tagging polymorphisms that characterize PRNP haplotypes from the promoter region through the three prime untranslated region of exon 3 (25.2 kb) were used to determine PRNP haplotypes of six available atypical BSE cases from Canada, France and the United States. One or two copies of a distinct PRNP haplotype were identified in five of the six cases (p = 1.3×10⁻⁴, two-tailed Fisher''s exact test; CI_95% 0.263–0.901, difference between proportions). The haplotype spans a portion of PRNP that includes part of intron 2, the entire coding region of exon 3 and part of the three prime untranslated region of exon 3 (13 kb).

Conclusions/Significance

This result suggests that a genetic determinant in or near PRNP may influence susceptibility of cattle to atypical BSE.