Contribution of insulin to the ascorbate recycling system in the chicken liver

The effect of insulin on the ascorbate recycling system in the chicken liver was examined. First, insulin was injected subcutaneously into the chicken, and liver glutathione‐dependent dehydroascorbate reductase (GSH‐DHAR) activity was determined. Insulin increased liver GSH‐DHAR activity, but did not affect plasma and liver ascorbate concentration. Dehydroascorbate increased plasma and liver ascorbate levels, and liver GSH‐DHAR activity. However, distinct changes in plasma insulin level were not observed by dehydroascorbate injection. In addition, reduction of external dehydroascorbate in cultured chicken hepatocytes could not be observed in an insulin‐deprived culture, although the cells reduced external dehydroascorbate in a serum‐free culture with insulin. We concluded that insulin affects the ascorbate recycling system as an essential factor in the chicken liver.     

Distribution of the pores of epithelial basement membrane in the rat small intestine

The distribution and diameter of the pores of epithelial basement membrane in the intestinal villi and the lymph nodules of ileal Peyer's patches were investigated in the rat small intestine by scanning electron microscopy after the removal of the overlying epithelial cells with OsO(4) maceration. In the duodenum, jejunum and ileum, the pores were mainly distributed at the upper three fourths of the villi, but were scarce around the top of the villi. The diameter of some of the pores in the upper three fourths of the villi was larger than that of those in the lower portion. The protrusion of lymphocytes and the cytoplasmic processes of macrophages were also seen at the orifices of the pores. In ileal Peyer's patches, in contrast, pores were densely distributed in the lower one third of the follicle-associated epithelium (FAE) where M cells were mainly seen. Furthermore, these pores were larger than those found in the upper two thirds. Lymphocytes or cytoplasmic processes of macrophages were frequently seen in the lower one third of FAE. These results suggest that the pores at the basement membrane correspond to the passage of the immunocompetent cells which are in contact with M cells or villous columnar epithelial cells and that the abundance of pores is a sign of aggressive interaction between the particular epithelial cells and the immunocompetent cells at the upper three fourths of intestinal villi and the lower one third of FAE in the rat small intestine.     

Identification of a potent immunostimulatory oligodeoxynucleotide from Streptococcus thermophilus lacZ

Immunostimulatory sequences of oligodeoxynucleotides (ODNs), such as CpG ODNs, are potent stimulators of innate immunity. Here, we identified a strong immunostimulatory CpG ODN, which we named MsST, from the lac Z gene of Streptococcus (S.) thermophilus ATCC19258, and we evaluated its immune functions. In in vitro studies, MsST had a similar ability as the murine prototype CpG ODN 1555 to induce inflammatory cytokine production and cell proliferation. In mouse splenocytes, MsST increased the number of CD80+CD11c+and CD86+CD11c+ dendritic cells and CD4+CD25+ regulatory T cells. We also analyzed the effects of MsST on the expression of regulatory cytokines by real-time quantitative PCR. MsST was more potent at inducing interleukin-10 expression than the ODN control 1612, indicating that MsST can augment the regulatory T cell response via Toll-like receptor 9, which plays an important role in suppressing T helper type 2 responses. These results suggest that S. thermophilus , whose genes include a strong Immunostimulatory sequence-ODN, is a good candidate for a starter culture to develop new physiologically functional foods and feeds.     

Effects on flowering and seed yield of dominant alleles at maturity loci E2 and E3 in a Japanese cultivar,Enrei

‘Enrei’ is the second leading variety of soybean (Glycine max (L.) Merr.) in Japan. Its cultivation area is mainly restricted to the Hokuriku region. In order to expand the adaptability of ‘Enrei’, we developed two near-isogenic lines (NILs) of ‘Enrei’ for the dominant alleles controlling late flowering at the maturity loci, E2 and E3, by backcrossing with marker-assisted selection. The resultant NILs and the original variety were evaluated for flowering, maturity, seed productivity and other agronomic traits in five different locations. Expectedly, NILs with E2 or E3 alleles flowered later than the original variety in most locations. These NILs produced comparatively larger plants in all locations. Seed yields were improved by E2 and E3 in the southern location or in late-sowing conditions, whereas the NIL for E2 exhibited almost the same or lower productivity in the northern locations due to higher degrees of lodging. Seed quality-related traits, such as 100-seed weight and protein content, were not significantly different between the original variety and its NILs. These results suggest that the modification of genotypes at maturity loci provides new varieties that are adaptive to environments of different latitudes while retaining almost the same seed quality as that of the original.     

Quantitative trait loci associated with lodging tolerance in soybean cultivar ‘Toyoharuka’

Lodging tolerance (LT) is an important trait for high yield and combine-harvesting efficiency in soybean [Glycine max (L.) Merr.]. Many previous studies have investigated quantitative trait loci (QTLs) for lodging score (LS) in soybean. Most of the investigated QTLs were located in the proximal region of maturity or growth habit loci. The aim of this study was to identify genetic factors for LT not associated with maturity or growth habit. QTL analysis was performed using a recombinant inbred line (RIL) population derived from a cross between ‘Toyoharuka’ (TH), a lodging-tolerant cultivar, and ‘Toyomusume’ (TM). The genotypes of TH and TM were estimated as both e1e2E3E4 and dt1. The average LS over 4 years was used for QTL analysis, identifying a major and stable QTL, qLS19-1, on chromosome 19. The LS of the near-isogenic line (NIL) with the TH allele at Sat_099, the nearest marker to qLS19-1, was significantly lower than the NIL with the TM allele at that position. The TH allele at Sat_099 rarely had a negative influence on seed yield or other agronomic traits in both NILs and the TM-backcrossed lines. Our results suggest that marker-assisted selection for qLS19-1 is effective for improving LT in breeding programs.     

N -Methyl- N -nitrosourea-induced Renal Tumors in Rats: Immunohistochemical Comparison to Human Wilms Tumors

N-Methyl-N-nitrosourea (MNU)-induced renal tumors in rats and Wilms tumors in humans were compared. Renal mesenchymal tumors (RMTs) and nephroblastomas (blastemal and epithelial components) in female Lewis rats treated with a single intraperitoneal injection of 50 mg/kg MNU at birth and Wilms tumors (blastemal, epithelial and mesenchymal components) in humans were analyzed for the expression of pancytokeratin (CK), vimentin, p63, α-smooth muscle actin (SMA), desmin, S-100, CD57, CD117/c-kit, Wilms tumor 1 protein (WT1) and β-catenin. The mesenchymal components of rat RMTs and human Wilms tumors expressed vimentin, SMA and β-catenin. The blastemal components of rat nephroblastomas and human Wilms tumors expressed vimentin, CD117/c-kit and β-catenin. The epithelial components of rat nephroblastomas and human Wilms tumors expressed vimentin and β-catenin. WT1 was expressed in different cellular components of rat tumors as compared with human Wilms tumors; the expression was seen in mesenchymal tumors and blastemal components of nephroblastomas in rats and epithelial components in human Wilms tumors. CK, p63 and CD57 were not expressed in rat RMTs or nephroblastomas, while CK and WT1 were expressed in epithelial components and CD57 was expressed in blastemal and epithelial components of human Wilms tumors. Rat and human tumors were universally negative for the expression of desmin and S-100. The immunohistochemical characteristics of rat renal tumors and human Wilms tumors may provide valuable information on the differences in renal oncogenesis and biology between the two species.     

Genetic diversity of wheat wild relatives in the Near East detected by AFLP

In order to reveal the molecular genetic diversity of wheat wild relatives, an AFLP analysis was conducted with 16 accessions of five Triticum andAegilops species originating from the Near East. Variation within population was studied with at least seven individuals per accession. Four primer combinations were used for selective amplification. Based on the scored bands, we estimated percentage of polymorphic bands, 1 – proportion of shared bands (1-psb) and nucleotide diversity (π). Of the five species used in this study, Ae. speltoides had the highest level of `within population' variation. This species had also the highest value of the variation among populations. As for Triticum species, the level of variation within population was low in diploid species (T. urartu and T. boeoticum),whereas two tetraploid species (T. dicoccoides and T. araraticum) had relatively high levels of variation within population. While the two diploid Triticum indicated a clear interspecific divergence, the two tetraploid wild wheats were not clearly divergent in this study. The variance portioning analysis indicated that the variation detected for diploid Triticum species was mainly composed of `between species' variation, on the other hand that for tetraploid Triticum was mostly composed of `within population' variation. In conclusion, AFLP analysis reveals molecular variation in all accessions used in this study, suggesting a potential genetic diversity of the wheat wild relatives in natural populations. These results have implications for the design of strategies to maintain genetic diversity within genebank collections. This revised version was published online in August 2006 with corrections to the Cover Date.