A releaser pheromone that attracts methyltestosterone- treated immature fish in the urine of ovulated female rainbow trout

SUMMARY: Behavioral experiments concerning a releaser pheromone in the urine of female rainbow trout were performed using immature fish administered orally with 17α-methyltestosterone (MT) during the non-spawning season. The urine was collected by catheter. The frequency of entries of test fish was recorded in each channel scented by test and control solutions in a Y-maze trough. The behavior of both MT-treated and control fish demonstrated that they could not discriminate the differences between distilled and environmental water as control solutions. There was also no difference between MT-treated and control fish when distilled and environmental water were introduced. The MT-treated immature fish were attracted to the channel scented by ovulated female urine. Neither coelomic fluid nor the immature female urine had any effect on the behavioral responses of MT-treated fish, while immature control fish had no preference for the urine of ovulated females. These results suggest in rainbow trout that ovulated female urine contains a releaser pheromone to attract mature males, and that androgens are involved in the sensory mechanisms detecting the releaser pheromone in fish.     

Seasonal variation in pigmentation and anthocyanidin phenetics in commercial Eustoma flowers

The seasonal change in petal color and pigmentation of 29 commercial Eustoma cultivars was studied. The flowers are basically divided into four groups according to the major anthocyanidin phenotype in association with petal coloration, i.e., delphinidin (Dp)-based (purple flower), cyanidin (Cy)-based (reddish purple flower), pelargonidin (Pg)-based (pink flower), and none (white flower) groups. The constitution of petal anthocyanidins was not changed by forcing treatment in most of the flowers. Lightness (L^*) and chroma (C^*, color saturation) showed a change along with the increase/decrease of hue angle difference (ΔH^*), thus simultaneously the chromatic tonalities tended to move to redder and bluer, respectively. Floral pigment clustering described two flower groups in a dendrogram, based on anthocyanidin constitutions as phenetic markers, which are apparently the Dp- and Pg-based phenotypes of anthocyanidin syntheses. The Cy-based flowers made a subcluster with the Pg-based flowers, indicating a close relationship in the biosynthesis of the two anthocyanidins, and suggesting the Dp- and Pg-syntheses complement one another.     

Monitoring of genetic diversity in the Japanese Black cattle population by the use of pedigree information

The gene pool of the Japanese Black cattle has been completely closed to foreign breeds during the last 100 years. Genetic diversity of the Japanese Black cattle from 1960 to 2000 was monitored with three estimates of effective number of ancestors. Founder genome equivalent (N_ge) accounts for all the causes of reduction of diversity. Effective number of founders (N_ef) and non‐founders (N_enf) explain reduced diversity because of unequal genetic contributions of founders and random genetic drift in non‐founders, respectively. Further examination using gene dropping simulation was conducted to obtain information on survival of founder alleles. Unique founder alleles were dropped down along the actual pedigree with Monte Carlo procedure following Mendelian segregation rules, and generated genotypes of all the current live animals (612 959 heads). Pedigree records consisted of 2 075 188 animals was used for these analysis. The estimates of three effective numbers (N_ef, N_ge, and N_enf) decreased from 418.6 to 50.3, 86.6 to 7.3, and 109.2 to 8.5, respectively, during the period 1960–2000. The increasing differences between two kinds of genetic diversity indices derived from N_ge and N_ef showed that large part of the reduced diversity from 1980 was attributed to genetic drift caused by the intensive use of particular limited number of sires. In gene dropping analysis, probabilities of extinction of founder alleles were derived from their distributions of frequency in the current animals. Several founders showed low probabilities of allele extinction, irrespective of their relatively low genetic contributions. This suggests that these founders have lineages through which their alleles are surely transmitted to the current breed. The use of these founders as a strategy for recovering the genetic diversity was discussed.     

Lactobacillus rhamnosus GG SpaC pilin subunit binds to the carbohydrate moieties of intestinal glycoconjugates

Lactobacillus rhamnosus GG (LGG) is a well‐established probiotic strain. The beneficial properties of this strain are partially dependent on its prolonged residence in the gastrointestinal tract, and are likely influenced by its adhesion to the intestinal mucosa. The pilin SpaC subunit, located within the Spa pili structure, is the most well studied LGG adhesion factor. However, the binding epitopes of SpaC remain largely unknown. The aim of this study was to evaluate the binding properties of SpaC to the carbohydrate moieties of intestinal glycoconjugates using a recombinant SpaC protein. In a competitive enzyme‐linked immunosorbent assay, SpaC binding was markedly reduced by addition of purified mucin and the mucin oligosaccharide fraction. Histochemical staining revealed that the binding of SpaC was drastically reduced by periodic acid treatment. Moreover, in the surface plasmon resonance‐based Biacore assay, SpaC bound strongly to the carbohydrate moieties containing β‐galactoside at the non‐reducing terminus of glycolipids. We here provide the first demonstration that SpaC binds to the oligosaccharide chains of mucins, and that the carbohydrate moieties containing β‐galactoside at the non‐reducing termini of glycoconjugates play a crucial role in this binding. Our results demonstrate the importance of carbohydrates of SpaC for mucus interactions.     

Evaluation of an indirect enzyme-linked immunosorbent assay (ELISA) using recombinant toxin for detection of antibodies against Pasteurella multocida toxin

To facilitate the control of progressive atrophic rhinitis (PAR) of swine caused by toxigenic Pasteurella multocida, an enzyme-linked immunosorbent assay (ELISA) and a serum neutralization test (NT) have recently been developed to detect antibodies against the P. multocida dermonecrotic toxin (PmDNT). However, the NT is a cumbersome and time-consuming technique. To overcome these drawbacks, we developed an indirect ELISA, using recombinant PmDNT expressed in Escherichia coli, for the detection of antibodies to PmDNT in serum samples from pigs. The practical usefulness of this ELISA was compared with the NT using serum samples obtained from experimentally infected and naturally infected pigs. In the pigs experimentally inoculated with vaccine including PmDNT toxoid, the ELISA and neutralization antibodies were detected at almost the same time, and a good correlation was demonstrated between both tests (P<0.01, R(2)=0.807). Therefore, the ELISA can be used to evaluate the immune reaction of pigs after vaccination with P. multocida toxoid. In a survey conducted on a field herd with a history of clinical AR, the seropositivity by ELISA in pigs of age 4.5-6 months was increased even though the NT was negative, and the correlation was low between the results obtained with the two tests (P<0.01, R(2)=0.38). Therefore, the results indicated that this ELISA might be a useful alternative to the NT currently used to detect the antibody to PmDNT after vaccination or infection with P. multocida.     

Phylogenetic characterization of rabies virus isolates from Carnivora in Brazil

The incidence of canine rabies has been widely reported in Brazil, and new rabies virus (RV) variants, genetically similar to canine RV, have recently been isolated from foxes. In order to derive the epidemiological characteristics of Brazilian Carnivora RV, Brazilian RVs isolated from dogs, cats, and foxes were genetically analyzed. Brazilian Carnivora RV isolates were divided into 2 main lineages. The predominant lineage was found in dogs and cats, which included the Argentinean and Bolivian Carnivora RV isolates, and was extensively distributed throughout Brazil and surrounding countries. The other lineage consisted of three sublineages containing Brazilian dog and fox RV isolates, with the dog sublineages located on an internal branch of 2 fox sublineages, suggesting that RV transmission events might have occurred between foxes and dogs in the past. These results suggest that contact between dogs and wildlife has the potential to generate new rabies variants and that it is important to control RV infection cycles in both dogs and wildlife to prevent spread of rabies infection.     

The incredible fungal genus —Drechslera — and its phytotoxic ophiobolins

ManyDrechslera species that haveCochliobolus sp. as a perfect stage produce a related group of ophiobolins, sesterterpenoids (C-25’s), which are phytotoxic to a wide range of plants. One of the most toxic ophiobolins is 6-epiophiobolin A and it is produced by all of theDrechslera species thus far studied. On the other hand, some novel ophiobolins have been found inD. oryzae: ophiobolin J, 6-epiophiobolin I, and 8-deoxyophiobolin J. Potentially, genetic crosses made between these fungi could yield novel organisms, producing novel combinations of the ophiobolins, and thus new pathotypes. Ophiobolins are being used in tissue culture systems to screen plants for sensitivity to these toxins. Paper presented at the Bat-Sheva Seminar on Host - Fungus Interaction, Jerusalem, Israel (March 14–25,1988).     

Inbreeding and effective population size of Japanese Black cattle

The objective of this research was to estimate the amount of inbreeding and effective population size of the Japanese Black breed using pedigree records from bulls and heifers registered between 1985 and 1997. Inbreeding was quantified by three F-statistics: actual inbreeding, inbreeding expected under random mating, and inbreeding due to population subdivision. During the period of 1985 to 1997, the inbreeding expected under random mating increased from 2.3% to 5.0%, whereas the increase of actual inbreeding was more gradual (from 4.7% to 5.4%). The inbreeding due to population subdivision decreased almost linearly and reached 0.5% in 1997, indicating that genetic subdivision of the Japanese Black cattle population has essentially disappeared. The effective size of the breed was estimated from the increasing rate of inbreeding expected under random mating. In the earlier half of this period (1986 to 1990), the breed maintained an effective size of approximately 30. However, after 1991 the effective size sharply decreased and the harmonic mean between 1993 and 1997 was only 17.2. The main cause of this reduction of the effective size was considered to be the intensive use of a few prominent sires. To increase the effective size, an upper limit in the use of AI semen per sire should be imposed.     

Isolation of Pathogenicity Mutants of Fusarium oxysporum f. sp. melonis by Insertional Mutagenesis

Restriction enzyme-mediated integration (REMI) mutagenesis was used to isolate mutants of Fusarium oxysporum f. sp. melonis impaired in pathogenicity. The race 2 strain Mel02010 was transformed with linearized pSH75, conferring resistance to hygromycin B, with or without the enzyme used to linearize the plasmid. Addition of restriction enzymes did not affect the transformation frequency. A total of 2929 REMI transformants were tested for pathogenicity to three melon cultivars, Amus, Ogon 9 and Ohi. The race 2 strains are pathogenic to Amus and Ogon 9, but not to Ohi. Of 43 transformants with reduced pathogenicity on susceptible melon cultivars, 12 mutants were examined in detail for pathogenicity, vegetative growth and integrative mode of pSH75. The levels of pathogenicity varied among these mutants. Two mutants (B48 and B137) almost completely lost pathogenicity to both susceptible cultivars, and the others had reduced pathogenicity. Mutants B48, B241, B886 and X36 were also impaired in vegetative growth. Mutant B809 was a biotin auxotroph. By DNA gel blot analysis, nine mutants were found to contain a single copy of the transformation vector. These mutants may thus be useful in isolating genes involved in pathogenicity. Received 22 December 2000/ Accepted in revised form 16 April 2001     

Time-dependent changes in protein phosphorylation patterns in rat brain synaptosomes caused by deltamethrin

Effects of deltamethrin, a powerful pyrethroid insecticide, on the protein phosphorylation and dephosphorylation processes during depolarization in rat brain synaptosomes were studied by using [³²P]phosphoric acid as a starting radiotracer and high external concentration of potassium ions or veratridine (10^?-5 M) as depolarizing agents. At the onset of depolarization there was a quick rise in phosphorylation in various synaptic proteins for about 15–30 s followed by a gradual decline in levels of phosphorylation. The effect of deltamethrin (10^?-7 M) on this system was found to be dependent on the length of preincubation of the synaptosome with the pesticide prior to depolarization. At an early stage (0–3 min preincubation period) it caused a modest suppression of protein phosphorylation activities. When the period of deltamethrin preincubation was extended to 5–20 min, however, it caused a significant increase in protein phosphorylation throughout the depolarization period. At the later stage of the action of deltamethrin (e.g. preincubation period of 30–40 min), deltamethrin-treated synaptosomes no longer responded to the depolarization signal to raise the level of phosphorylation on many proteins. These results indicate that deltamethrin's actions on the synaptic process are complex. Depending on the length of exposure, its effects on protein phosphorylation responses in intact synaptosomes could be either stimulatory or inhibitory. To study the cause of deltamethrin-induced synaptic block at the later stage, effects of deltamethrin on protein kinases were studied by using lysed synaptic membranes with [gamma-³²P]ATP. Deltamethrin was shown to inhibit calcium–calmodulin-dependent protein phosphorylation activities at 10^?-7 M when given directly to the enzyme source 10 min prior to the addition of [³²P]ATP. Such an observation helps to explain the inhibitory action of deltamethrin on protein phosphorylation which occurs at the late stage of its action (i.e. preincubation time > 20 min).