Induction of an organ-specific autoimmune disease, lymphocytic hypophysitis, in hamsters by recombinant rubella virus glycoprotein and prevention of disease by neonatal thymectomy.

Glycosylated, membrane-associated E1 (58-kDa) and E2 (47- to 49-kDa) rubella virus proteins and unglycosylated nucleoprotein C (33 kDa), from separately expressed vaccinia virus recombinants, were injected into golden Syrian hamsters. Rubella virus E1 and E2 glycoproteins consistently induced an organ-specific autoimmune disease, autoimmune lymphocytic hypophysitis, which was evidenced by the induction of autoantibodies against pituitary cells and by lymphocytic infiltration of the pituitary. Neonatal thymectomy prevented the disease. In contrast, rubella virus nucleoprotein C did not induce either autoantibodies against pituitary cells or lymphocytic infiltration of the pituitary. This finding raises the possibility that virus-specific protein itself can induce an organ-specific autoimmune disease in certain circumstances.     

Vancomycin derivative with damaged D-Ala-D-Ala binding cleft binds to cross-linked peptidoglycan in the cell wall of Staphylococcus aureus

Des-N-methylleucyl-4-(4-fluorophenyl)benzyl-vancomycin (DFPBV) retains activity against vancomycin-resistant pathogens despite its damaged d-Ala-d-Ala binding cleft. Using solid-state nuclear magnetic resonance (NMR), a DFPBV binding site in the cell walls of whole cells of Staphylococcus aureus has been identified. The cell walls were labeled with d-[1-(13)C]alanine, [1-(13)C]glycine, and l-[epsilon-(15)N]lysine. Internuclear distances from (19)F of the DFPBV to the (13)C and (15)N labels of the cell-wall peptidoglycan were determined by rotational-echo double-resonance (REDOR) NMR. The (13)C{(19)F} and (15)N{(19)F} REDOR spectra show that, in situ, DFPBV binds to the peptidoglycan as a monomer with its vancosamine hydrophobic side chain positioned near a pentaglycyl bridge. This result suggests that the antimicrobial activity of other vancosamine-modified glycopeptides depends upon both d-Ala-d-Ala stem-terminus recognition (primary binding site) and stem-bridge recognition (secondary binding site).     

Two enzymes in one; two yeast peroxiredoxins display oxidative stress-dependent switching from a peroxidase to a molecular chaperone function

Although a great deal is known biochemically about peroxiredoxins (Prxs), little is known about their real physiological function. We show here that two cytosolic yeast Prxs, cPrxI and II, which display diversity in structure and apparent molecular weights (MW), can act alternatively as peroxidases and molecular chaperones. The peroxidase function predominates in the lower MW forms, whereas the chaperone function predominates in the higher MW complexes. Oxidative stress and heat shock exposure of yeasts causes the protein structures of cPrxI and II to shift from low MW species to high MW complexes. This triggers a peroxidase-to-chaperone functional switch. These in vivo changes are primarily guided by the active peroxidase site residue, Cys(47), which serves as an efficient "H(2)O(2)-sensor" in the cells. The chaperone function of these proteins enhances yeast resistance to heat shock.     

Hypoglycemic effects of exopolysaccharides produced by mycelial cultures of two different mushrooms Tremella fuciformis and Phellinus baumii in ob/ob mice

The anti-diabetic activities of the exopolysaccharides (EPS) produced by submerged mycelial culture of two different mushrooms, Tremella fuciformis and Phellinus baumii, in ob/ob mice were investigated. All the animals were randomly divided into three groups with seven animals in each group: The control group received 0.9% NaCl solution; the diabetic groups were treated with EPS from T. fuciformis (Tf EPS) and P. baumii (Pb EPS) at the level of 200 mg/kg body weight using an oral zoned daily for 52 days. The plasma glucose levels in the EPS-fed mice were substantially reduced by about 52% (Tf EPS) and 32% (Pb EPS), respectively, as compared to control mice. The results of oral glucose tolerance test (OGTT) revealed that both EPS-fed groups significantly increased the glucose disposal after 52 days of EPS treatments. Furthermore, higher food efficiency ratios and reduced blood triglyceride levels were observed in the EPS-treated groups. Because peroxisome proliferator-activated receptor gamma (PPAR-γ) is indeed a key regulator of insulin action, we investigated the expression pattern of adipose tissue PPAR-γ messenger RNA (mRNA) and plasma levels of PPAR-γ. It was revealed that PPAR-γ was significantly activated in response to EPS treatments. The results suggested that both EPS exhibited considerable hypoglycemic effect and improved insulin sensitivity possibly through regulating PPAR-γ-mediated lipid metabolism. Our results indicated that two mushroom-derived EPS might be developed as potential oral hypoglycemic agents or functional foods for the management of non-insulin-dependent diabetes mellitus.     

Regulation of cyclin-dependent kinase inhibitor p21<Superscript>WAF1/CIP1</Superscript> by protein kinase Cδ-mediated phosphorylation

Cyclin-dependent kinase (CDK) inhibitor p21^{WAF1/CIP1(-/-)}-null mice have an increased incidence of tumor formation. Here, we demonstrate that p21^WAF1/CIP1 is unstable in HeLa cells treated with siRNA duplexes that target PKCδ. PKCδ phosphorylates p21^WAF1/CIP1 at a serine residue (¹⁴⁶Ser) located in its C-terminal domain. In cells treated with 12-O-tetradecanoylphorbol 13-acetate, the levels of both p21^WAF1/CIP1 and its ¹⁴⁶Ser-phosphorylated form increased significantly. We also show that a substitution, resulting from a single nucleotide polymorphism (SNP) at ¹⁴⁹Asp found in certain cancer patients, strongly compromises PKCδ-mediated phosphorylation at ¹⁴⁶Ser and results in cells that are relatively resistant to TNFα-induced apoptosis. Thus, post-translational phosphorylation of p21^WAF1/CIP1 is important from an apoptotic cell death, and may also have patho-physiological relevance for the development of human cancer.     

Amyotrophic lateral sclerosis is associated with hypolipidemia at the presymptomatic stage in mice

Objective

To demonstrate that hypolipidemia is a typical feature of the mouse model of amyotrophic lateral sclerosis (ALS) and to assess the association between hypolipidemia and disease stage, dietary intake, and sex.

Methods

We compared daily dietary intake, body weight, and serumlipid and glucose levels in ALS mice and wild-type controls at different stages of the disease.

Findings

Total cholesterol low-density lipoprotein (LDL) and LDL/high-density lipoprotein (HDL) ratio were significantly lower in ALS mice compared with controls. Subgroup analysis revealed that the incidence of hypolipidemia was significantly greater in male, but not female, ALS mice compared with control mice and that hypolipidemia was present at the presymptomatic stage of the disease. This hypolipidemia can be found without a decrease in the serum levels of other energy sources, such as glucose, in the presymptomatic stage.

Conclusions

Hypolipidemia is present at the presymptomatic stage of the ALS mouse model in the absence of malnutrition, significant neuromuscular degeneration or regeneration, and respiratory difficulty. Our findings suggest that hypolipidemia might be associated with the pathomechanism of ALS and/or lipid-specific metabolism rather than simply an epiphenomenon of neuromuscular degeneration or energy imbalance.     

Production of 7,10-dihydroxy-8(<Emphasis Type="Italic">E</Emphasis>)-octadecenoic acid from olive oil by <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> PR3

Microbial modification of naturally occurring materials is one of the efficient ways to add new values to them. Hydroxylation of free unsaturated fatty acids by microorganism is a good example of those modifications. Among microbial strains studied for that purpose, a new bacterial isolate Pseudomonas aeruginosa PR3 has been well studied to produce several hydroxy fatty acids from different unsaturated fatty acids. Of those hydroxy fatty acids, 7,10-dihydroxy-8(E)-octadecenoic acid (DOD) was efficiently produced from oleic acid by strain PR3. However, it was highly plausible to use vegetable oil containing oleic acid rather than free oleic acid as a substrate for DOD production by strain PR3. In this study, we firstly tried to use olive oil containing high content of oleic acid as a substrate for DOD production. DOD production from olive oil was confirmed by structural determination with GC, TLC, and GC/MS analysis. DOD production yield from olive oil was 53.5%. Several important environmental factors were also tested. Galactose and glutamine were optimal carbon and nitrogen sources, and magnesium ion was critically required for DOD production from olive oil. Results from this study demonstrated that natural vegetable oils containing oleic acid could be used as efficient substrate for the production of DOD by strain PR3.