Regional Distribution of Two Races of <Emphasis Type="Italic">Phialophora gregata </Emphasis>f. sp. <Emphasis Type="Italic">adzukicola, </Emphasis>Causal Agent of Brown Stem Rot of Adzuki Bean,and Their Genetic Diversity on Hokkaido,Northernmost Island of Japan

The distribution of two races (1 and 2) of Phialophora gregata f. sp. adzukicola, the causal agent of brown stem rot of adzuki bean, was examined using a total of 483 isolates obtained from 39 fields in 19 locations on Hokkaido, Japan between 1997 and 1999. Race 1 was predominant (416 isolates or 86.1%) in the commercial fields tested. Race 2 was found in 25 fields (64.1%), including two fields of cultivar Kita-no-otome (resistant to race 1, but susceptible to race 2), indicating that race 2 was widely distributed in most of the production areas in Hokkaido. Using amplified fragment length polymorphisms (AFLP), a total of 67 polymorphic AFLP markers was recorded among 72 representative isolates (37 and 35 isolates of races 1 and 2, respectively), and 57 distinct haplotypes were detected. Cluster analysis revealed no close correlation between races and AFLP groups. Thus, no difference was observed between values of gene diversity in each race (0.253 and 0.284 in races 1 and 2, respectively), and the coefficient of gene differentiation was very low (G _ST =0.015). Gene differentiation between both races by analysis of molecular variance was not significantly different from zero (Φ=−0.001; p=0.403). However, the results of gene differentiation among regional populations (G _ST =0.290, Φ=0.292; p<0.001) are not necessarily consistent with the result that isolates from the same district were generally not tightly clustered. Received 15 April 2002/ Accepted in revised form 6 September 2002     

Enhancement of chicken resistance against Escherichia coli infection by oral administration of Bifidobacterium thermophilum preparations

Three types of Bifidobacterium thermophilum extract were prepared and fed to 2-wk-old chickens to evaluate their usefulness in enhancing the defense activity of the chickens against pathogenic Escherichia coli. All three preparations resulted in significant reduction (P < 0.05) of E. coli numbers in the lungs of the treated chicken groups compared with the control nontreated group. Besides, improvement in the survival rate was observed in the treated chicken groups, especially the one administered the enzyme-digested B. thermophilum extract sample. Concanavalin A-stimulated lymphocytes from the latter group demonstrated significantly higher proliferation activity compared with those from the control group. These results suggest that oral administration of B. thermophilum preparations may be used to enhance the resistance of chickens against E. coli infection.     

Feed intake, lactation performance, blood metabolites and fertility in early lactation dairy cows grazing a timothy pasture

The present study was conducted to investigate feed intake, milk yield, milk composition, blood metabolites and fertility in early lactation dairy cows grazing a timothy pasture. Fourteen multiparous Holstein cows that calved between 20 May and 19 July were used over a 3‐year period. The stocking rate was 3.6–4.3 cow/ha. Concentrates were fed separately at 9.5–11.5 kg/day per cow (dry matter basis) from 1 to 13 weeks postparturition. Herbage intake was estimated using chromium oxide as an indigestible marker. The mean contents of crude protein, total digestible nutrients and neutral detergent fiber of pasture during the 3‐year study period were 22.3%, 71.8% and 51.7%, and those of total diet were 18.9%, 77.3% and 40.3%, respectively. The mean herbage dry matter intake was 13.0 kg/day from 2 to 13 weeks postparturition during the study, total dry matter intake was 23.7 kg/day, the total digestible nutrients sufficiency rate was 105%, milk yield was 39.7 kg/day, and milk fat percentage was 3.30%. The decrease in bodyweight postparturition was slight. Urea nitrogen concentrations in serum were below 18.3 mg/dL. The mean days to first estrus and days open were 36 and 104 days, respectively. These results indicate that energy deficiency, decrease in bodyweight and fertility in early lactation barely occur when high producing dairy cows are fed enough grazing grass and suitable concentrates.     

Establishment of a model for chemoattraction of <Emphasis Type="Italic">Symbiodinium</Emphasis> and characterization of chemotactic compounds in <Emphasis Type="Italic">Acropora tenuis</Emphasis>

Corals harbor symbiotic dinoflagellates, Symbiodinium spp., acquired from surrounding environments. Because Symbiodinium are present at low densities in the water column, corals may attract these symbionts using chemotactic compounds. To examine whether corals contain chemotactic compounds, we established an assay to measure the chemotactic activity for Symbiodinium using an extract of the coral Acropora tenuis, a major reef-building coral in Japan. Our assay revealed that Symbiodinium strain NBRC102920 (clade A), which is taken up by juvenile A. tenuis polyps, is attracted to crude A. tenuis extracts. We found that the chemotactic compounds are water-soluble, heat-labile macromolecules and that the chemotactic activity was inhibited by N-acetyl-d-glucosamine (GlcNAc). We separated the GlcNAc-binding fraction (Fr-ActL) and identified it as the most plausible candidate for the chemoattractant, since the chemotactic activity of the crude A. tenuis extract appeared to be mainly attributable to the activity of Fr-ActL and was also inhibited by the addition of GlcNAc. These results indicate that chemoattraction is mediated via the binding of Symbiodinium to Fr-ActL.     

Development of an assay system using thrips-mediated inoculation to evaluate resistance of Capsicum spp. to Tomato spotted wilt virus

Considerable losses in pepper production by Tomato spotted wilt virus (TSWV) have been reported worldwide. In breeding programs, an assay for resistance that accurately estimates field occurrence of TSWV during pepper production is critical because the virus is vector transmitted. Here, we establish an assay system of TSWV-resistant Capsicum spp. using insect-mediated inoculation within an acrylic chamber in which environmental conditions such as temperature, light intensity, and nutrient supply are controlled. This chamber enables transmission of TSWV from viruliferous plants to plants used in the resistance assay with Frankliniella occidentalis safely, quickly, and precisely.     

Isolation of multiple drug-resistant enteric bacteria from feces of wild Western Lowland Gorilla (Gorilla gorilla gorilla) in Gabon

Prevalence of drug-resistant bacteria in wildlife can reveal the actual level of anthropological burden on the wildlife. In this study, we isolated two multiple drug-resistant strains, GG6-2 and GG6-1-1, from 27 fresh feces of wild western lowland gorillas in Moukalaba-Doudou National Park, Gabon. Isolates were identified as Achromobacter xylosoxidans and Providencia sp., respectively. Minimum inhibitory concentrations of the following 12 drugs—ampicillin (ABPC), cefazolin (CEZ), cefotaxime (CTX), streptomycin (SM), gentamicin (GM), kanamycin (KM), tetracycline (TC), nalidixic acid (NA), ciprofloxacin (CPFX), colistin (CL), chloramphenicol (CP) and trimethoprim (TMP)—were determined. Isolate GG6-2 was resistant to all antimicrobials tested and highly resistant to CTX, SM, TC, NA and TMP. Isolate GG6-1-1 was resistant to ABPC, CEZ, TC, CL, CP and TMP.     

Breed Differences in Dopamine Receptor D4 Gene (DRD4) in Horses

Genetic polymorphisms in genes related to neurotransmitters or hormones affect personality or behavioral traits in many animal species including humans. In domestic animals, the allele frequency of such genes has been reported to be different among breeds and it may account for breed differences in behavior. In this study, we investigated breed differences in horses in the dopamine receptor D4 gene (DRD4), which has been reported to affect horse personality. We collected samples from seven horse breeds including those native to Japan and Korea, and compared the sequence of the DRD4 exon3 region among these breeds. We found that there were two types of polymorphisms (VNTR and SNPs) in the exon3 region, and some of them seemed to be breed-specific. In addition, we found that the allele frequency of G292A, reported to be associated with horse personality, differed greatly between native Japanese horses and Thoroughbred horses. The frequency of the A allele which is associated with low curiosity and high vigilance, was much lower in native Japanese horses (Hokkaido, 0.03; Taishu, 0.08) than in Thoroughbreds (0.62). This difference may account for breed differences in personality or behavioral traits. Further studies of the function of these polymorphisms and their effect on behavior are indicated.     

Characterization of Alpha-fetoprotein Levels in Three Dolphin Species: Development of Sensitive Immunoassays for Analysis of the Pregnancy-associated Variations

A single radial immunodiffusion (SRID) assay and a chemiluminescent immunoassay (CLIA) were initially developed for alpha-fetoprotein (AFP) of the striped dolphin. Utilizing these developed assays, we investigated pregnancy-associated changes in the levels of AFP in the sera of fetuses and pregnant females of three dolphin species; samples were either collected from captive individuals or obtained as fishery by-products. The concentrations of AFP in the fetal serum ranged from 419.0 to 2026.3 μg/ml in the striped dolphin, 12.6 to 1218.7 μg/ml (for an AFP equivalent; eqAFP) in the common bottlenose dolphin and 770.6 to 3129.1 μg eqAFP/ml in the Risso''s dolphin. AFP levels decreased with increased fetal size in fetuses over 20 cm in length. The concentrations of AFP in sera of pregnant females ranged from 7.18 to 8068.7 ng/ml in the striped dolphin, 6.6 to 1241.1 ng eqAFP/ml in the common bottlenose dolphin and 3.4 to 2868.7 ng eqAFP/ml in the Risso''s dolphin. The levels in most pregnant females were equal to or lower than those found in males and nonpregnant individuals, although a few pregnant females exhibited extremely high levels (in the range of hundreds to thousands of nanograms per milliliter). Such high levels of AFP were not observed during pseudopregnancy. To our knowledge, this is the first report on basal profiles for serum AFP levels in small odontocetes. The profiles indicated that AFP may play a significant role during embryonic development, although maternal levels do not appear to be a diagnostic biomarker for monitoring pregnancy.     

Habitat shift of ayu Plecoglossus altivelis altivelis in early stages from waters adjacent to the bank to the center of flow in the Shimanto Estuary

ABSTRACT: To clarify the habitats of the ayu in the early stages of development in the Shimanto Estuary, the size and hatching date of the larval and juvenile ayu were examined. Sizes of larvae and juveniles were larger in the center of the flow area than in the waters adjacent to the estuary's banks, which suggests that larvae shift habitat to the center of flow from the waters along the estuary's banks. This shift began at approximately 20 mm body length. However, the resident term in the waters adjacent to the estuary's banks changed with the hatching dates; that is, the early and late-hatched larvae became short and long-term residents, respectively. A similar phenomenon was found also in the juveniles collected in the freshwater section that were migrating upstream. The growth rates of larval ayu in the waters adjacent to the banks tended to decrease with hatching dates. The fluctuations in growth rate with hatching date appear to be a factor leading to the variation of resident term.