Forced expression of FLO11 confers pellicle-forming ability and furfural tolerance on Saccharomyces cerevisiae in ethanol production

We constructed a plasmid that expresses FLO11 encoding a cell surface glycoprotein of Saccharomyces cerevisiae under the control of a constitutive promoter. This plasmid conferred pellicle-forming ability on the non-pellicle-forming industrial strain of S. cerevisiae at the air–liquid interface of the glucose-containing liquid medium. The induced pellicle-forming cells exhibited tolerance to furfural, which is a key toxin in lignocellulosic hydrolysates, in ethanol production.     

Receptive field of the stemmata in the swallowtail butterflyPapilio

Summary Receptive fields of individual retinular cells in the stemmata ofPapilio xuthus L. were examined electrophysiologically, and the receptive field of the complete stemmatal system was reconstructed (Fig. 8).In stemmata I-IV, proximal retinular cells have narrow receptive fields (acceptance angles of = 1.7–5 °, Fig. 5) and small inclinations of the visual axes (inclinations of = 0.7–1.5 °, Fig. 2) with respect to the axis of the stemma, while distal ones have wide fields ( =7–13 °, Fig. 5) and large inclinations of the visual axes ( = 5–10 °, Fig. 3). In stemmata V and VI, both proximal and distal retinular cells have wide receptive fields ( = 7–26 °, Fig. 6) and have large inclinations of their visual axes ( = 9–19 °) with respect to the axis of the stemma except for one proximal cell ( = 0 °) (Fig. 4).The spatial properties of distal and proximal retinular cells, combined with the finding that distal cells are homogeneous in the spectral sensitivity while proximal ones are heterogeneous (Ichikawa and Tateda 1980), suggest that the distal cells may be concerned largely with the detection of objects and proximal cells are involved with the discrimination of the color and shape of the detected objects.     

Growth characteristics of Heterosigma akashiwo virus and its possible use as a microbiological agent for red tide control

The growth characteristics of Heterosigma akashiwo virus clone 01 (HaV01) were examined by performing a one-step growth experiment. The virus had a latent period of 30 to 33 h and a burst size of 7.7 x 10(2) lysis-causing units in an infected cell. Transmission electron microscopy showed that the virus particles formed on the peripheries of viroplasms, as observed in a natural H. akashiwo cell. Inoculation of HaV01 into a mixed algal culture containing four phytoplankton species, H. akashiwo H93616, Chattonella antiqua (a member of the family Raphidophyceae), Heterocapsa triquetra (a member of the family Dinophyceae), and Ditylum brightwellii (a member of the family Bacillariophyceae), resulted in selective growth inhibition of H. akashiwo. Inoculation of HaV01 and H. akashiwo H93616 into a natural seawater sample produced similar results. However, a natural H. akashiwo red tide sample did not exhibit any conspicuous sensitivity to HaV01, presumably because of the great diversity of the host species with respect to virus infection. The growth characteristics of the lytic virus infecting the noxious harmful algal bloom-causing alga were considered, and the possibility of using this virus as a microbiological agent against H. akashiwo red tides is discussed.     

Cold exposure suppresses serum adiponectin levels through sympathetic nerve activation in mice

Objective: Several lines of evidence suggest important roles for adiponectin in glucose and lipid metabolism and atherosclerosis. However, the mechanisms regulating serum adiponectin levels and adiponectin production are still not completely understood. Our aim was to determine whether adiponectin synthesis is physiologically regulated by the sympathetic nervous system (SNS). Research Methods and Procedures: Mice were exposed to cold (4 °C) for 12 hours and for 24 hours with or without inhibition of noradrenaline synthesis or pan‐β adrenergic function, followed by measurement of serum adiponectin concentrations and levels of adiponectin and uncoupling protein (UCP) 1 expressions in various white adipose tissues (WATs). Results: Cold exposure significantly reduced serum adiponectin concentrations without changing body weights or WAT sizes in either subcutaneous or intra‐abdominal fat tissues. The serum adiponectin reduction was associated with a decrease in adiponectin mRNA expression in subcutaneous, epididymal, and mesenteric fat tissues. In these adipose tissues, UCP1 expression was markedly enhanced, suggesting SNS activation in these tissues. Administration of α‐methyl‐p‐tyrosine or a combination of SR59230A and propranolol reversed the cold‐exposure‐induced decreases in serum adiponectin concentrations and adiponectin mRNA expression in these tissues. In contrast, in retroperitoneal fat, the effects of cold exposure on adiponectin and UCP1 expressions were strikingly weak but were not reversed by SNS inhibitors. Discussion: SNS physiologically regulates serum adiponectin levels and adiponectin synthesis in WATs in vivo, although responsiveness to SNS stimulation differs markedly among WATs. Sympathetic activation might be involved in development of the metabolic syndrome by modulation of serum adiponectin concentrations.     

Cell type-specific activation of metabolism reveals that beta-cell secretion suppresses glucagon release from alpha-cells in rat pancreatic islets

Abnormal glucagon secretion is often associated with diabetes mellitus. However, the mechanisms by which nutrients modulate glucagon secretion remain poorly understood. Paracrine modulation by beta- or delta-cells is among the postulated mechanisms. Herein we present further evidence of the paracrine mechanism. First, to activate cellular metabolism and thus hormone secretion in response to specific secretagogues, we engineered insulinoma INS-1E cells using an adenovirus-mediated expression system. Expression of the Na+-dependent dicarboxylate transporter (NaDC)-1 resulted in 2.5- to 4.6-fold (P < 0.01) increases in insulin secretion in response to various tricarboxylic acid cycle intermediates. Similarly, expression of glycerol kinase (GlyK) increased insulin secretion 3.8- or 4.2-fold (P < 0.01) in response to glycerol or dihydroxyacetone, respectively. This cell engineering method was then modified, using the Cre-loxP switching system, to activate beta-cells and non-beta-cells separately in rat islets. NaDC-1 expression only in non-beta-cells, among which alpha-cells are predominant, caused an increase (by 1.8-fold, P < 0.05) in glucagon secretion in response to malate or succinate. However, the increase in glucagon release was prevented when NaDC-1 was expressed in whole islets, i.e., both beta-cells and non-beta-cells. Similarly, an increase in glucagon release with glycerol was observed when GlyK was expressed only in non-beta-cells but not when it was expressed in whole islets. Furthermore, dicarboxylates suppressed basal glucagon secretion by 30% (P < 0.05) when NaDC-1 was expressed only in beta-cells. These data demonstrate that glucagon secretion from rat alpha-cells depends on beta-cell activation and provide insights into the coordinated mechanisms underlying hormone secretion from pancreatic islets.     

SNP-SNP Interactions Discovered by Logic Regression Explain Crohn's Disease Genetics

In genome-wide association studies (GWAS), the association between each single nucleotide polymorphism (SNP) and a phenotype is assessed statistically. To further explore genetic associations in GWAS, we considered two specific forms of biologically plausible SNP-SNP interactions, ‘SNP intersection’ and ‘SNP union,’ and analyzed the Crohn''s Disease (CD) GWAS data of the Wellcome Trust Case Control Consortium for these interactions using a limited form of logic regression. We found strong evidence of CD-association for 195 genes, identifying novel susceptibility genes (e.g., ISX, SLCO6A1, TMEM183A) as well as confirming many previously identified susceptibility genes in CD GWAS (e.g., IL23R, NOD2, CYLD, NKX2-3, IL12RB2, ATG16L1). Notably, 37 of the 59 chromosomal locations indicated for CD-association by a meta-analysis of CD GWAS, involving over 22,000 cases and 29,000 controls, were represented in the 195 genes, as well as some chromosomal locations previously indicated only in linkage studies, but not in GWAS. We repeated the analysis with two smaller GWASs from the Database of Genotype and Phenotype (dbGaP): in spite of differences of populations and study power across the three datasets, we observed some consistencies across the three datasets. Notable examples included TMEM183A and SLCO6A1 which exhibited strong evidence consistently in our WTCCC and both of the dbGaP SNP-SNP interaction analyses. Examining these specific forms of SNP interactions could identify additional genetic associations from GWAS. R codes, data examples, and a ReadMe file are available for download from our website: http://www.ualberta.ca/~yyasui/homepage.html.     

But1 and But2 proteins bind to Uba3, a catalytic subunit of E1 for neddylation, in fission yeast

NEDD8/Rub1 is the most homologous protein to ubiquitin among the ubiquitin-like proteins, and it is covalently linked to target proteins via the C-terminal glycine residue in a manner analogous to ubiquitylation. However, the mechanism(s) involved in the regulation of the NEDD8 ligation pathway remains elusive. Using the two-hybrid system, we isolated novel genes from the Schizosaccharomyces pombe cDNA library whose products bind to Uba3, which is a catalytic protein for E1-like activity of the NEDD8 pathway. We designated these genes but1(+) and but2(+) (for proteins that bind to Uba three). But1 is a nuclear protein and its overexpression caused cell elongation, which is a common phenotype of the NEDD8 pathway defective mutant in S. pombe. Furthermore, overexpression of but1(+) in ned8-temperature sensitive mutant had a deleterious effect even under permissive temperatures. Our results suggest that But1 may have an inhibitory role in the NEDD8 pathway.     

Excessive Cytokine Response to Rapid Proliferation of Highly Pathogenic Avian Influenza Viruses Leads to Fatal Systemic Capillary Leakage in Chickens

Highly pathogenic avian influenza viruses (HPAIVs) cause lethal infection in chickens. Severe cases of HPAIV infections have been also reported in mammals, including humans. In both mammals and birds, the relationship between host cytokine response to the infection with HPAIVs and lethal outcome has not been well understood. In the present study, the highly pathogenic avian influenza viruses A/turkey/Italy/4580/1999 (H7N1) (Ty/Italy) and A/chicken/Netherlands/2586/2003 (H7N7) (Ck/NL) and the low pathogenic avian influenza virus (LPAIV) A/chicken/Ibaraki/1/2005 (H5N2) (Ck/Ibaraki) were intranasally inoculated into chickens. Ty/Italy replicated more extensively than Ck/NL in systemic tissues of the chickens, especially in the brain, and induced excessive mRNA expression of inflammatory and antiviral cytokines (IFN-γ, IL-1β, IL-6, and IFN-α) in proportion to its proliferation. Using in situ hybridization, IL-6 mRNA was detected mainly in microglial nodules in the brain of the chickens infected with Ty/Italy. Capillary leakage assessed by Evans blue staining was observed in multiple organs, especially in the brains of the chickens infected with Ty/Italy, and was not observed in those infected with Ck/NL. In contrast, LPAIV caused only local infection in the chickens, with neither apparent cytokine expression nor capillary leakage in any tissue of the chickens. The present results indicate that an excessive cytokine response is induced by rapid and extensive proliferation of HPAIV and causes fatal multiple organ failure in chickens.