Net blotch resistance in wild species of Hordeum

Resistance to net blotch was evaluated in 175 Hordeum vulgare subsp. spontaneum (H. spontaneum) accessions and 149 accessions of thirteen species or subspecies of wild Hordeum. Most H. spontaneum accessions showed resistance to each of the four Pyrenophora teres f. teres (P. teres) isolates tested. However, H. spontaneum accessions showed different resistance reactions, depending upon their origin. In particular, some accessions from Afghanistan and Russia showed a high level of resistance, and accessions from Morocco were susceptible. Among the four P. teres isolates, the virulence spectra on the H. spontaneum accessions were more different between isolates from different countries than between those from the same country. Hordeum spontaneum accessions susceptible to the Canadian isolate WRS102, but resistant to the other three isolates were found in Iraq suggesting the geographical differentiation of resistance genes in H. spontaneum. All accessions of the other wild Hordeum species, especially some accessions of H. marinum subsp. gussoneanum, showed high levels of resistance. These resistance genes may be useful candidates for incorporation into cultivated barley. This revised version was published online in July 2006 with corrections to the Cover Date.     

Artificial incubation of Japanese crayfish (Cambaroides japonicus) eggs by using a simple, easy method with a microplate

We developed a simple, easy method with a microplate to artificially incubate Japanese crayfish (Cambaroides japonicus) eggs for their cultivation. We prepared 6-, 12-, 24-, 48-, and 96-well microplates containing sterile water heated to 5, 10, 15, and 20 °C. Fourteen experimental groups for each water temperature were prepared for each of different water volumes (0.125–10 ml) in each well. One embryonic egg was placed in each well. Experiments were also conducted with water collected from the lake where the eggs were harvested from and held at 15 °C. In the microplates with sterile water, high proportions of eggs hatched (60–100%) at 15 °C in all volumes of water, although the proportions of hatching were low (0–20%) at 5, 10, and 20 °C. All eggs died in the experiments that used lake water. We conclude that the 96-well would be the most effective size to hatch crayfish eggs in, because of its convenience. This method using a microplate is simpler and easier compared with methods of previous studies to artificially incubate crayfish eggs, and therefore it might be useful to incubate eggs of other freshwater crayfish species.     

Chromosome arm location of the gene controlling leaf pubescence of a Chinese local wheat cultivar ‘Hong-mang-mai’

The inheritance of the leaf pubescence character of a Chinese local wheat cultivar ‘Hon-mang-mai’ was investigated by monosomic and telosomic analyses. Leaf pubescence was evaluated by observation of the adaxial side of the penultimate leaf of adult plants. F₁ hybrids of ‘Hong-mang-mai’ with a non-pubescent cultivar ‘Chinese Spring’ had leaf pubescence, but its density was about a half of that of ‘Hong-mang-mai’. In the F₂ generation, the segregation ratio of pubescent to non-pubescent plants fitted a ratio of 3: 1, suggesting that leaf pubescence was controlled by one dominant gene. Monosomic analysis revealed that the gene for pubescence is located on chromosome 7B. Telosomic analysis showed that the gene is located on the short arm of chromosome 7B with a distance of 14.3%from the centromere. This gene is not allelic with the previously reported hairy leaf gene Hl on chromosome 4B, and therefore, is designated Hl2, hairy leaf 2. This revised version was published online in July 2006 with corrections to the Cover Date.     

A System for Identification of Potato Varieties Using SNP Dosage

As in autoteraploids, five genotypes are possible in a biallelic locus, allele dosage could be useful for variety identification in potato. DNA sequences of 13 genes associated with tuber yield, tuber starch content or late blight resistance were surveyed for single nucleotide polymorphism (SNP) in eight tetraploid varieties. A total of 193 potential SNPs was found by Sanger-sequencing, of which 58 were measured for nucleotide frequencies using a pyrosequencer. Of the 58 SNPs, 35 yielded distinct clusters, corresponding to allele dosages. Among these, six were highly correlated with another, leaving 29 independent SNP loci for use in variety discrimination. By using dosage scores at the 29 SNP loci, it was possible to differentiate 115 varieties, except for a sport with red tuber skin color, with at least three different SNP dosages. Therefore, using SNP dosages is a simple, fast and reliable tool for variety identification.     

Urinary corticoid to creatinine ratios using IMMULITE 2000 XPi for diagnosis of canine hypercortisolism

The urinary corticoid to creatinine ratio (UCCR) is one of the most commonly used screening tests for canine hypercortisolism (HC). In this study, a reference interval was established for UCCR using IMMULITE 2000 XPi, the latest chemiluminescence enzyme immunoassay. The diagnostic performance of this method for UCCR in canine HC was also evaluated. The median UCCR was 1.06 × 10⁻⁵ (range: 0.28–2.49) for 58 healthy dogs, and an upper reference limit of 1.98 × 10⁻⁵ (90% confidence interval: 1.76–2.15) was determined. The median UCCR in the 12 dogs with HC (7.38 × 10⁻⁵, range 1.86–29.98) was significantly higher than that in the 16 dogs with mimic-HC (1.59 × 10⁻⁵, range 0.47–3.42, P<0.001). The area under the curve for UCCR to differentiate HC dogs from mimic-HC dogs was 0.971, with a sensitivity of 91.7% and specificity of 100% when the cut-off value was set at 3.77 × 10⁻⁵. The UCCR of 16 paired urine samples collected at home and in hospital showed that the UCCR of samples collected in the hospital was significantly higher than that of samples collected at home (mean difference 3.30 × 10⁻⁵, 95% confidence interval: 0.70–5.90, P=0.001). In summary, we established the upper reference limit for UCCR using IMMULITE 2000 XPi in dogs and confirmed that UCCR is a useful diagnostic test for HC in dogs if urine samples are collected at home.     

A genetic map ofSolanum phureja clone 1.22 constructed using RFLP and RAPD markers

A genetic map of a widely used haploid inducer,Solanum phureja clone 1.22, was constructed. One hundred and twenty-two RFLP and twenty RAPD marker bands were specific toS. phureja clone 1.22, and were mapped on 100 loci (five to eleven loci per chromosome) in the span of 606 cM. These would be useful to monitor the chromosomes of the haploid inducer that may be eliminated from triploid embryos of 4x × 2x during the process of haploid induction from potato.     

Effects of growth factors on development of fetal islet B-cells in vitro

To investigate the role of growth factors (epidermal growth factor [EGF], betacellulin, and activin A) in the development of islet B cells of rat fetal pancreatic explants in vitro, pancreases from rat fetuses at day 18 of gestation were cultured for 96 hr, with or without these growth factors. Culture medium was changed every 24 hr, and the level of insulin released in the culture medium was measured. After 72 hr of culture, pancreases were examined histologically. As a result, EGF promoted cell proliferation, but reduced B cell volume. Whereas, betacellulin and activin A inhibited cell division, but promoted increased B cell volume and insulin secretion, especially activin A, which stimulated insulin release in a time dependent manner. These results suggest that EGF, betacellulin, and activin A promote pancreatic cell proliferation, islet B-cell differentiation, and islet B-cell differentiation and functional maturation, respectively, and that EGF, betacellulin, and activin A, in this order, regulate islet B-cell neogenesis.     

Diesel exhaust particle toxicity on spermatogenesis in the mouse is aryl hydrocarbon receptor dependent

Diesel exhaust particles (DEPs) are particulate matter from diesel exhaust containing many toxic compounds, such as polyaromatic hydrocarbons (PAHs). Some toxicities of PAH are considered to express via aryl hydrocarbon receptor (AhR). We hypothesized that the male reproductive toxicity of DEPs may depend on PAHs. BALB/c male mice received 24.7, 74.0 or 220 microg/mouse DEP suspension or vehicle injected into the dorsal subcutaneous layer 10 times during 5 weeks. The mice were euthanized, and blood and organs were collected 2 weeks after the last treatment. The epididymis weights, relative epididymis weights per body weight and daily sperm productions and viabilities of the 74.0 and 220 microg/mouse DEP-treated groups decreased significantly compared with those of the vehicle group. The total incidence of sperm abnormalities in the 74.0 and 220 microg/mouse DEP-treated groups increased significantly compared with the vehicle group. The seminiferous epithelium area ratios of the 74.0 and 220 microg/mouse DEP-treated groups were significantly higher compared with the vehicle and 24.6 microg/mouse DEP-treated groups. The ratios of seminiferous tubules with elongated-type spermatids in the 74.0 and 220 microg/mouse DEP-treated groups were significantly decreased compared with the vehicle group. The testosterone level and hepatic ethoxyresorufin-O-deethylase (EROD) activity as an indirect index of AhR activity in the 74.0 microg/mouse DEP-treated group were significantly increased compared with those of the vehicle group. These results clearly demonstrated that DEPs suppress testicular function, especially spermatogenesis and sperm motility. These effects may be AhR dependent.     

4-Nitro-3-phenylphenol has both androgenic and anti-androgenic-like effects in rats

To investigate the effect of endocrine disruption of 4-nitro-3-phenylphenol (PNMPP) on immature male Wistar-Imamichi rats, the rat pituitary was exposed to PNMPP (10^–5–10^–9 M) for 24 h with or without gonadotropin-releasing hormone (GnRH) in experiment I. In addition, the Leydig cells (10^–5–10^–9 M) were exposed to PNMPP for 24 h with or without human chronic gonadotropin (hCG) in experiment II. Our results showed that the PNMPP at 10^–5–10^–7 M suppressed follicle-stimulating hormone (FSH) and luteinizing hormone (LH) productions from GnRH-stimulated pituitary cells. At the same time, PNMPP 10^–5–10^–7 M induced an increase in testosterone production from the Leydig cells treated with or without hCG. Based on our results, it can be concluded that that PNMPP might have both androgen agonist action by decreasing FSH and LH production in the pituitary and anti-androgenic action by increasing testosterone production in the Leydig cell.