Suppression of overt diabetes in NOD mice by anti-thymocyte serum or anti-Thy 1, 2 antibody

Effects of anti-thymocyte serum (ATS) and anti-Thy 1, 2 monoclonal antibody on the spontaneously occurring diabetes in NOD mice were examined. Spontaneous diabetes in female mice was markedly suppressed by intravenous injection of rabbit anti-mouse thymocyte serum diluted to 1:4 on three consecutive days during the time period from 70 to 100 days after birth; the cumulative incidence of overt diabetes upto 195 days of age was greatly reduced and the onset of diabetes was delayed. Similar effect was observed with anti-Thy 1, 2 antibody treatment. These findings suggest that T lymphocytes play a role in the production of spontaneous diabetes in this mouse strain.     

A sexual difference in the chromosomes of two species of agamid lizards

Summary The diploid number of chromosomes in Calotes versicolor is 34 in the male and 33 in the female. The numerical difference in the two sexes is based on the condition of the sex chromosome; in the male it is present as a homologous pair, while in the female it remains unpaired. The sex chromosome was identified as one of the micro-chromosomes (the chromosome No. 7) in this species. Sitana ponticeriana possesses the diploid number of 46 in the male and 45 in the female. The sex chromosome identified in this form is also one of the micro-chromosomes (chromosome No. 13), which has no partner in the female, whereas in the male it is in the paired state having a homologous mate.It was established therefore that, in both species studied, the female is heterogametic as regards the sex chromosome.The chromosome complement of Calotes versicolor consists of 12 V-shaped macro-chromosomes and 22 dot-like micro-chromosomes, while in Sitana ponticeriana there are 24 rod-shaped macro-chromosomes and 22 dot-like micro-chromosomes. The difference in the karyotypes of these two species can be accounted for on the basis of the formation of V-shaped multiple chromosomes by means of the fusion of two rods at the point of fibre attachment.The karyological relationships in the Family Agamidae were discussed. The chromosome number previously reported for Uromastix hardwicki was found to be erroneous; the diploid number in this species is 34.Contribution No. 214 from the Zoological Institute, Faculty of Science, Hokkaido University, Sapporo, Japan.     

Proliferation of donor mitochondrial DNA in nuclear transfer calves (Bos taurus) derived from cumulus cells

In embryos derived by nuclear-transfer (NT), fusion of donor cell and recipient oocyte caused mitochondrial heteroplasmy. Previous studies from other laboratories have reported either elimination or maintenance of donor-derived mitochondrial DNA (mtDNA) from somatic cells in cloned animals. Here we examined the distribution of donor mtDNA in NT embryos and calves derived from somatic cells. Donor mitochondria were clearly observed by fluorescence labeling in the cytoplasm of NT embryos immediately after fusion; however, fluorescence diminished to undetectable levels at 24 hr after nuclear transfer. By PCR-mediated single-strand conformation polymorphism (PCR-SSCP) analysis, donor mtDNAs were not detected in the NT embryos immediately after fusion (less than 3-4%). In contrast, three of nine NT calves exhibited heteroplasmy with donor cell mtDNA populations ranging from 6 to 40%. These results provide the first evidence of a significant replicative advantage of donor mtDNAs to recipient mtDNAs during the course of embryogenesis in NT calves from somatic cells.     

Effect of dietary fiber on the lipid metabolism and immune function of aged Sprague-Dawley rats

Eight-month-old Sprague-Dawley rats were fed on diets containing dietary fiber at the 5% level for 3 weeks to examine the effect on the lipid metabolism and immune function. Among cellulose, guar gum, partially hydrolyzed guar gum (PHGG), glucomannan and highly methoxylated pectin, guar gum induced a significant decrease in the food intake and weight gain, as well as a significant increase in the liver weight. In addition, the epidydimal adipose tissue weight of the rats fed on PHGG was significantly higher than that of the rats fed on cellulose. There was no significant effect on the serum lipid levels, but the serum IgG level of the rats fed on guar gum was significantly lower than that of the rats fed on cellulose. The IgA and IgG productivity in mesenteric lymph node (MLN) lymphocytes was significantly higher in the rats fed on guar gum, glucomannan and pectin than in those fed on cellulose, while the effect on Ig productivity in spleen lymphocytes was not as marked. In addition, only guar gum induced a significant increase of IgM productivity in MLN lymphocytes when compared to the cellulose group. These results suggest that enhancement of the immune function by dietary fiber is mainly expressed in the gut immune system.     

Regulation of IL-11 expression in intestinal myofibroblasts: role of c-Jun AP-1- and MAPK-dependent pathways

IL-11 inhibits the activation of NF-kappaB and induces the Th2 polarization of CD4+ T cells. The clinical utility of IL-11 is being investigated in Crohn's disease. However, physiological secretion of IL-11 in the intestine remains unclear. In this study, we investigated IL-11 secretion in human intestinal subepithelial myofibroblasts (SEMFs). Intestinal SEMFs were isolated from the human colonic mucosa. IL-11 secretion and mRNA expression were determined by ELISA and Northern blot analysis. The activating protein (AP)-1-DNA binding activity was evaluated by EMSA. IL-11 secretion was induced by IL-1beta and transforming growth factor (TGF)-beta1. These were also observed at the mRNA level. The EMSAs demonstrated that both IL-1beta and TGF-beta1 induced AP-1 activation within 2 h after stimulation, and a blockade of AP-1 activation by the recombinant adenovirus containing a dominant negative c-Jun markedly reduced the IL-1beta- and TGF-beta1-induced IL-11 mRNA expression. IL-1beta and TGF-beta1 induced an activation of ERK p42/44 and p38 MAP kinases, and the MAP kinase inhibitors (SB-202190, PD-98059, and U-0216) significantly reduced the IL-1beta- and TGF-beta1-induced IL-11 secretion. The upregulation of IL-11 mRNA by IL-1beta- and TGF-beta1 was also mediated by a p38 MAP kinase-mediated mRNA stabilization. The combination of IL-1beta and TGF-beta1 additively enhanced IL-11 secretion. Intestinal SEMFs secreted IL-11 in response to IL-1beta- and TGF-beta1. Mucosal IL-11 secretion might be important as an anti-inflammatory response in the pathogenesis of intestinal inflammation.     

Filamentous bacteriophages of vibrios are integrated into the dif-like site of the host chromosome

The dif site is located in the replication terminus region of bacterial chromosomes, having a function of resolving dimeric chromosomes formed during replication. We demonstrate that filamentous bacteriophages of vibrios, such as f237 (Vibrio parahaemolyticus) and CTXphi (V. cholerae), are integrated into the dif-like site of host chromosome.     

Establishment of Alternative Culture Method for Spermatogonial Stem Cells Using Knockout Serum Replacement

Since spermatogonial stem cells (SSCs) are capable of both self-renewal and differentiation to daughter cells for subsequent spermatogenesis, the development of an efficient in vitro culture system is essential for studies related to spermatogenesis. Although the currently available system is serum-free and contains only chemically-defined components, it highly relies upon bovine serum albumin (BSA), a component with batch-to-batch quality variations similar to those of fetal bovine serum. Thus, we searched for an alternative BSA-free culture system that preserved the properties of SSCs. In this study, we utilized Knockout Serum Replacement (KSR) in the SSC culture medium, as a substitute for BSA. The results demonstrated that KSR supported the continuous growth of SSCs in vitro and the SSC activity in vivo without BSA, in a feeder-cell combination with mouse embryonic fibroblasts. The addition of BSA to KSR further facilitated cell cycle progression, whereas a transplantation assay revealed that the addition of BSA did not affect the number of SSCs in vivo. The combination of KSR with BSA also allowed the elimination of GFRA1 and FGF2, and the reduction of the GDNF concentration from 20 ng/ml to 5 ng/ml, while maintaining the growth rate and the expression of SSC markers. Furthermore, KSR was also useful with SSCs from non-DBA/2 strains, such as C57BL/6 and ICR. These results suggested that KSR is an effective substitute for BSA for long-term in vitro cultures of SSCs. Therefore, this method is practical for various studies related to SSCs, including spermatogenesis and germ stem cell biology.     

The effects of gene disruption of Kre6-like proteins on the phenotype of β-glucan-producing Aureobasidium pullulans

Applied Microbiology and Biotechnology - Killer toxin resistant 6 (Kre6) and its paralog, suppressor of Kre null 1 (Skn1), are thought to be involved in the biosynthesis of cell wall...