Transglutaminase activity during the differentiation of macrophages

For the examination of the participation of the microsomal electron transport system in mutagenic activation by 4-dimethylaminoazobenzene (DAB), 4-methylaminoazobenzene (MAB) and their 3′-methyl-derivatives (3′-methyl-DAB and 3′-methyl-MAB), monospecific antibodies to NADPH-cytochrome P-450 reductase, 3-methylcholanthrene-inducible major P-450 (MC-P-448) and phenobarbital-inducible major P-450 (PB-P-450) were used. In Ames' assay system, the antibody to NADPH-cytochrome P-450 reductase inhibited the mutagenicities of DAB, MAB, 3′-methyl-DAB and 3′-methyl-MAB by 94, 94, 90 and 87%, respectively. The antibody to MC-P-448 inhibited their mutagenicities by more than 90%, while the antibody to PB-P-450 inhibited the mutagenicities less than 20%. These results indicate that the microsomal electron transport system, especially MC-P-448, is involved in activation of these dyes.     

Automated screening and primer design of fish microsatellite DNA loci on pyrosequencing data

In recent years, massive sequencing approaches have allowed us to determine genomic structures of various organisms rapidly, raising novel applicability of the high-throughput sequence data obtained to various fields of biological studies. We present here a pipeline to search for microsatellite DNA and design PCR primers encompassing the microsatellites on genomic sequence data produced by 454 pyrosequencing. We tested this pipeline, called ‘Auto-primer’, on several fish genomic sequences and obtained many and various candidates for microsatellite DNA loci useful for detecting intraspecies genetic variability. This in silico search for microsatellite DNA is superior to conventional cloning methods, since any sequence patterns of repeat unit can be screened.     

Thermal stress and diabetic complications

Activities of erythrocyte aldose reductase were compared in 34 normal subjects, 45 diabetic patients, and nine young men following immersion in water at 25, 39, and 42° C. Mean basal enzyme activity was 1.11 (SEM 0.12) U/g Hb and 2.07 (SEM 0.14) U/g Hb in normal controls and diabetic patients, respectively (P<0.0001). Activities of the enzyme showed a good correlation with hemaglobin A₁ (HbA₁) concentrations (P<0.01) but not with fasting plasma glucose concentrations. After immersion at 42° C for 10 min, enzyme activity was increased by 37.6% (P<0.01); however, the activity decreased by 52.2% (P<0.005) after immersion for 10 min at 39° C and by 47.0% (P<0.05) at 25° C. These changes suggest that heat stress might aggravate diabetic complications, and body exposure to hot environmental conditions is not recommended for diabetic patients.     

Balneotherapy and platelet glutathione metabolism in type II diabetic patients

Effects of balneotherapy on platelet glutathione metabolism were investigated in 12 type II (non-insulin-dependent) diabetic patients. Levels of the reduced form of glutathione (GSH) on admission were well correlated with those of fasting plasma glucose (FPG;r=0.692,P<0.02). After 4 weeks of balneotherapy, the mean level of GSH showed no changes; however, in well-controlled patients (FPG <150 mg/dl), the level increased (P<0.01) and in poorly controlled patients (FPG >150 mg/dl), the value decreased (P<0.05). There was a negative correlation between glutathione peroxidase (GPX) activities and the levels of FPG (r=–0.430,P<0.05). After balneotherapy, the activity increased in 5 patients, decreased in 3 patients and showed no changes (alteration within ±3%) in all the other patients. From these findings in diabetic patients we concluded: (1) platelet GSH synthesis appeared to be induced in response to oxidative stress; (2) lowered GPX activities indicated that the antioxidative defense system was impaired; and (3) platelet glutathione metabolism was partially improved by 4 weeks balneotherapy, an effect thought to be dependent on the control status of plasma glucose levels. It is suggested that balneotherapy is beneficial for patients whose platelet antioxidative defense system is damaged, such as those with diabetes mellitus and coronary heart disease.     

Possible involvement of transglutaminase in endocytosis and antigen presentation

Experiments were carried out to determine as to whether or not internalization of antigen is necessary for subsequent antigen presentation by accessory cells using monoamines which are known as transglutaminase (TGase) inhibitors. It was found that endocytosis for immune complexes via Fc receptors such as sheep erythrocytes coated with IgG class antibody (EA) was different from receptor-independent endocytosis for soluble protein such as horse radish peroxidase (HRP) in the sensitivity to monoamines; methylamine inhibited the receptor-dependent endocytosis of immune complexes at a concentration of over 20 mM and the receptor-independent endocytosis of HRP at 2 mM, while dansylcadaverine (DC) inhibited both at a concentration of 100 microM. It was noteworthy that antigen-specific T cell proliferation to splenic adherent cells pulsed with DNP9.6-ovalbumin (DNP9.6-OVA) was blocked strongly by DC as well, but weakly by methylamine. These results suggest the possibility that antigen presentation requires internalization of antigen by a mechanism such as receptor-dependent endocytosis for the subsequent reexpression of antigen on membranes. Furthermore, it was confirmed that TGase activity is high in peritoneal exudate and spleen adherent cells, both of which have accessory cell activities for lymphocytes, suggesting the possibility that TGase might be involved intimately in receptor-dependent endocytosis and subsequent antigen presentation.