Endocrine control of the reproductive activity in hibernating bats

Bats, Chiroptera, constitute the second largest order of the class Mammalia and vary greatly in habitats, available foods and mating systems. The timing, duration and patterns of reproduction in bats vary considerably among species and different localities. Though much is known about the reproductive phenomena and associated endocrine characteristics of various species, the central mechanism regulating the peculiar delay and asynchrony in reproductive activity remains to be elucidated. The current understanding on the endocrine characteristics and possible mechanism of regulation of the hypothalamo-adenohypophysial-gonadal axis of bats will be reviewed, based mainly on our own studies in hibernating rhinolophid bats.     

Isolation of mini-Tn5Km2 insertion mutants of Salmonella enterica serovar Oranienburg sensitive to NaCl-induced osmotic stress

We previously reported that the viability of Salmonella Oranienburg strains under NaCl stress was variable and depended on the strain's origin; food strains were resistant and patient strains sensitive to NaCl. Therefore, we mutagenized a food strain with a mini-Tn5Km2 transposon. Of 2,400 mutants screened, 15 NaCl-sensitive mutants were isolated, and 7 genes associated with NaCl-sensitivity were identified. The intact genes complemented their own food-strain mutants, but not patient-strain mutants, suggesting that the difference in NaCl-sensitivity between food and patient S. Oranienburg strains might not arise from a single gene mutation, but from change in multiple osmoregulatory mechanisms in Salmonella.     

Natural vanadium-containing Mt. Fuji ground water improves hypo-activity of liver insulin receptor in Goto-Kakisaki rats

After daily treatments with Mt. Fuji ground water containing natural vanadium (approximately 65 microg/l) at doses of 0.53 microg/kg/day for 12 weeks, blood glucose (BG), serum hemoglobin A1C (HbA1C) levels and insulin secretion from the pancreas of Goto-Kakisaki (GK) rats, a genetic model of Type 2 diabetes, were improved. In GK rat liver insulin receptors, the binding properties of [125I] insulin, and the activities of insulin receptor beta subunit and primary insulin-like growth factor-1beta all recovered to normal levels of those found in Wistar rats. These results suggest that daily treatment with small concentrations of natural vanadium improves hyperglycemia by ameliorating liver insulin receptor activity.     

Enolase in the RNA degradosome plays a crucial role in the rapid decay of glucose transporter mRNA in the response to phosphosugar stress in Escherichia coli

The ptsG mRNA encoding the major glucose transporter is rapidly degraded in an RNase E-dependent manner in response to the accumulation of glucose 6-P or fructose 6-P when the glycolytic pathway is blocked at its early steps in Escherichia coli. RNase E, a major endonuclease, is associated with polynucleotide phosphorylase (PNPase), RhlB helicase and a glycolytic enzyme, enolase, which bind to its C-terminal scaffold region to form a multienzyme complex called the RNA degradosome. The role of enolase within the RNase E-based degradosome in RNA decay has been totally mysterious. In this article, we demonstrate that the removal of the scaffold region of RNase E suppresses the rapid degradation of ptsG mRNA in response to the metabolic stress without affecting the expression of ptsG mRNA under normal conditions. We also demonstrate that the depletion of enolase but not the disruption of pnp or rhlB eliminates the rapid degradation of ptsG mRNA. Taken together, we conclude that enolase within the degradosome plays a crucial role in the regulation of ptsG mRNA stability in response to a metabolic stress. This is the first instance in which a physiological role for enolase in the RNA degradosome has been demonstrated. In addition, we show that PNPase and RhlB within the degradosome cooperate to eliminate short degradation intermediates of ptsG mRNA.     

Isolation of thermophilic ammonium-tolerant bacterium and its application to reduce ammonia emission during composting of animal wastes

A thermophilic bacterium, strain TAT105, was isolated from compost made of animal wastes. TAT105 had high tolerance to ammonium nitrogen up to 1200 mM, and highly assimilated nitrogen during the growth on swine feces. The strain was classified into Bacillus, close to Bacillus pallidus. To evaluate the effect of adding TAT105 to ammonia (NH3) emission during the composting process of animal wastes, laboratory scale composting was done. NH3 emission tended to be lower and nitrogen loss was smaller in the TAT105-added material than in the control material to which TAT105 was not added. Thermophilic ammonium-tolerant bacteria in the TAT105-added material increased to about 8x10(9) CFU/g of dry matter on the average during the tests, and most of them were judged to be TAT105 from morphological colony discrimination. These results suggested the possibility of reducing NH3 emission from composting of animal wastes by adding TAT105.     

A new cell-permeable peptide allows successful allogeneic islet transplantation in mice

Calcineurin inhibitors such as cyclosporine A and FK506 have been used for transplant therapy and treatment of autoimmune diseases. However, the inhibition of calcineurin outside the immune system has a number of side effects, including hyperglycemia. In the search for safer drugs, we developed a cell-permeable inhibitor of NFAT (nuclear factor of activated T cells) using the polyarginine peptide delivery system. This peptide provided immunosuppression for fully mismatched islet allografts in mice. In addition, it did not affect insulin secretion, whereas FK506 caused a dose-dependent decrease in insulin secretion. Cell-permeable peptides can thus provide a new strategy for drug development and may eventually be useful clinically.     

Protective immunity of SpaA-antigen producing Lactococcus lactis against Erysipelothrix rhusiopathiae infection

AIMS: To develop an economical, safe and simple vaccination system against swine erysipelas using SpaA-antigen producing Lactococcus lactis. METHODS AND RESULTS: The spaA gene of Erysipelothrix rhusiopathiae was inserted into a shuttle plasmid pSECE1 to construct pSECE1.3. The SpaA produced in L. lactis maintained a stable antigenicity without degrading in growth. After mice were inoculated intranasally and orally with pSECE1.3-carrying L. lactis cells, IgG and IgA specific to SpaA were detected, and all the mice survived a challenge with 100 LD(50) of E. rhusiopathiae Tama-96 in the inner thigh. CONCLUSIONS: SpaA-producing L. lactis appears useful as an effective subunit vaccine against swine erysipelas. SIGNIFICANCE AND IMPACT OF THE STUDY: In this vaccination system, purification of the antigen and injection are unnecessary, leading to a reduced production cost, reduced labour and less stress to the animals. This vaccination system of the lactic acid bacteria should be a safe and suitable vehicle for a polyvalent vaccine.     

Immobilization of cycloisomaltooligosaccharide glucanotransferase for the production of cycloisomaltooligosaccharides from dextran

Immobilization of cycloisomaltooligosaccharide glucanotransferase (CITase) and its application in the production of cycloisomaltooligosaccharides (CIs) from dextran were studied. Among various carrier materials examined, the enzyme adsorbed physically on Chitopearl BCW-3505 showed the highest activity (1.75 U/ml carrier). The activity remaining was 35%. The maximum CI yield in batch reactions at 0.2, 2 and 10% dextran was 28, 24 and 12%, respectively. The maximum CI yield at 2% dextran (24%) was slightly less than that with the free enzyme under the same conditions (26%). The concentration of linear oligosaccharides, the byproducts in the reaction mixture, was greater with the immobilized CITase than the free enzyme. The immobilized CITase was less thermostable than the free enzyme by about 10 degrees C. The pattern of influence of Ca(2+) concentration on the thermostability differed between the free and immobilized CITase. A Ca(2+) concentration of 50-100 mM was optimum for the thermostability of the immobilized CITase, 10-50 mM for the free enzyme. CIs were produced continuously by a column system packed with the immobilized enzyme at 40 degrees C with a space velocity (SV) of 6 h(-1). The three quarters life time was 4 weeks. We think that relatively long life time at fast SV was accomplished and CI production cost by this method should be lower than the batch reaction. This is the first report on immobilization of CITase.