Immunohistochemical localization of inhibin subunits in the testis of the bull

The differential localization of the inhibin beta subunits betaA and betaB in the testis of adult bull was studied using specific monoclonal and polyclonal primary antibodies. Inhibin betaA- and betaB-subunits were localized only in the Sertoli cells. The inhibin betaA-subunit was observed in the cytoplasm while the betaB-subunit was localized in the nucleus. No specific findings depending on spermatogenic stages were observed among the seminiferous tubules. Moreover, the inhibin alpha-subunit was not detected in the testis of the bulls. In addition, no inhibin subunits were detected in the Leydig cells and spermatogenic cells. These findings indicate the presence of betaA- and betaB-subunits in the bull, which may suggest a possibility that activin is produced and/or stored in the Sertoli cells and regulates spermatogenesis in an autocrine/paracrine manner. Moreover, the inhibin betaB-subunit may be produced in the nucleus but the functional meaning of this is not yet clear.     

Trail antigen in Eimeria stiedai sporozoites associated with a thrombospondin-related motif and the entry of cultured cells

In order to examine the antigenic similarity and specificity of the trail antigen of Eimeria stiedai and Etp 100, a microneme protein of Eimeria tenella, monoclonal antibodies to the trail antigen of E. stiedai sporozoites were selected by an indirect immunofluorescent antibody method. The monoclonal antibody of one clone, 3D10, reacted with the anterior portion of non-fixed sporozoites. By immunoblotting, the monoclonal antibody was found to react with a 100 kDa antigen of E. stiedai sporozoites, and a 117 kDa antigen of E. tenella sporozoites and merozoites. It was also found to react with a recombinant protein with thrombospondin-/properdin-like motifs homologous to E. tenella microneme protein Etp 100. The monoclonal antibody significantly inhibited the penetration of E. stiedai sporozoites into cultured rabbit hepatobiliary epithelial cells. These results suggest that E. stiedai sporozoites have a trail antigen, located in the anterior region on the outer surface of the sporozoites, which has an epitope with thrombospondin-/properdin-like motifs similar to E. tenella microneme protein Etp 100. This protein may play an important functional role in the process of penetration of host cells.     

Arthroderma benhamiae infection in a rabbit

The isolate from the rabbit with dermatophytosis which was transmitted to the owners was proved to be Arthroderma benhamiae (-) by mating experiments as well as by chitin synthase 1 (CHSI) gene analysis.     

Identification of novel inhibitors of calling and in vitro [14C]acetate incorporation by pheromone glands of Plodia interpunctella

Some octopamine agonists were found to suppress in vitro biosynthesis of the calling pheromone of the Indian meal moth, Plodia interpunctella. Isolated pheromone-gland preparations incorporated sodium [14C]acetate at a linear rate for 3 h when incubated with the pheromone biosynthesis activating neuropeptide (PBAN). This incorporation was dependent on the dose of PBAN (up to 0.5 microM). Thin-layer chromatography of a pheromone-gland extract revealed quantitative incorporation of radioactivity into a product exhibiting the same mobility as (Z,E)-9,12-tetradecadienyl acetate, the main component of the calling pheromone of P interpunctella. Twenty-seven octopamine agonists were initially screened using a calling behaviour bioassay of female P interpunctella. Four derivatives with activity in the nanomolar range were identified which were, in order of decreasing pheromonostatic activity: 2-(2,6-diethylphenylimino)thiazolidine > 2-(2,6-diethylphenylimino)oxazolidine > 2-(2,6-dimethylphenylimino)thiazolidine > 2-(2-ethylphenylimino)oxazolidine. These compounds also showed in vitro inhibitory activity in intracellular de novo pheromone biosynthesis. The results of the present study indicate that these derivatives could provide useful information in the characterization and differentiation of octopaminergic receptor types and subtypes.     

Identification of Trichoderma SKT-1, a biological control agent against seedborne pathogens of rice

Trichoderma SKT-1 was previously reported as a powerful biological control agent against seedborne pathogens of rice, but the taxonomic disposition of the fungal isolate was not clear. Trichoderma SKT-1 produced irregular pyramidal warts on conidia and had an optimum growth temperature of 30°C. Morphological characteristics and colony growth were identical to those of known species of Trichoderma, including the newly recognized species T. asperellum. The 5.8S rDNA with the internal transcribed spacer (ITS) region (ca. 514 bp) of the fungus was compared with those of known species to determine the phylogenetic placement of the fungus. The length and sequence of the regions from Trichoderma SKT-1 were completely identical to those of an isolate of T. asperellum NRRL 5242 (AJ230669). On the basis of these results, we concluded that Trichoderma SKT-1 was T. asperellum.     

Growth Complementation of hrpXo Mutants of Xanthomonas oryzae pv. oryzae by Virulent Strains in Rice Cultivars Resistant and Susceptible to the Parental Strain

Xanthomonas oryzae pv. oryzae (X. o. pv. oryzae) T7174 is virulent on rice cultivar IR24 and avirulent on IR-BB2. From recent reports, some virulence and avirulence factors of plant pathogenic bacteria are transferred to plant cells through the hrp-dependent type III secretion system. In this study, we investigated the involvement of hrp genes in the compatible and the incompatible interactions between rice and X. o. pv. oryzae after co-inoculation with hrpXo mutants derived from T7174 and virulent strains. Growth of the mutants, named 74ΔHrpXo and 76ΔHrpXo, was repressed in IR24 when the mutants were applied alone. However, growth of the mutants was complemented by co-inoculation with virulent strains. Growth of bioluminescent hrpXo mutant 76ΔHrpXo in IR24 and its growth in IR-BB2 after co-inoculation with T7133, which is virulent on both cultivars, was equally complemented, as detected by bioluminescence from the mutant. On the other hand, only partial complementation of growth of T7174L76, which is a bioluminescent and pathogenic derivative of T7174, by T7133 was observed in IR-BB2. Thus, growth of the hrpXo mutant of X. o. pv. oryzae was complemented by virulent strains in both susceptible and resistant rice leaves with the parental strain. Received 21 July 2000/ Accepted in revised form 26 October 2000     

Antimicrobial activity of some N-(arylalkyl)maleimides

A series of N-(arylalkyl)maleimides was prepared for the reaction of maleic anhydride and N-(arylalkyl) amines, and their antimicrobial activities were examined. All compounds exhibited antibacterial activity against gram-positive bacteria such as Bacillus subtilis and Staphylococcus aureus. Almost all compounds exhibited antibacterial activity against the gram-negative bacterium, Escherichia coli, but were inactive against Pseudomonas aeruginosa. Activities against gram-positive bacteria were independent of the nature of the substituent on the benzene ring or the length of alkyl group, but that against gram-negative bacteria was influenced by these parameters. All N-(arylalkyl)maleimides showed activity against yeasts and mycelial fungi.     

Molecular heterogeneity in clinical isolates of Malassezia pachydermatis from dogs

Molecular investigation of 16 strains, conventionally identified to be Malassezia pachydermatis, isolated from dogs in Japan was carried out by random amplification of polymorphic DNA (RAPD) and chitin synthase 2 (CHS2) gene sequence analyses. The RAPD band patterns of 13 clinical isolates were identical to that of standard strain of M. pachydermatis (CBS-1879). The other three clinical isolates were different from the standard strain of M. pachydermatis in RAPD patterns, and two of the three isolates were identical. About 620 bp genomic DNA fragments of the CHS2 gene were amplified from the same 16 clinical isolates of M. pachydermatis by polymerase chain reaction (PCR) and sequenced. The phylogenetic analysis of the nucleotide sequences of CHS2 gene fragments of the 16 clinical isolates revealed that the 13 strains were genetically very close to the standard strain of M. pachydermatis and the other two isolates were genetically close to the standard strain of M. furfur rather than M. pachydermatis. The remaining one isolate was phylogenetically distinct from all the seven Malassezia species reported so far.     

Ultrastructural Changes in Calvarial Osteoblast Cytoskeleton after Prostaglandin E2 Administration in Rats

Recent studies on the cytoskeleton of osteoblasts have been made mainly using cultured cells. However, the morphology of cultured cells may be altered during subculture. Therefore, cytoskeletal changes of calvarial osteoblasts were investigated in situ by electron microscopy using the detergent perfusion method to preserve cell morphology as well as selectively observing the cytoskeleton in the presence of a high concentration of prostaglandin E2 (PGE2) in the calvarial periphery in rats. Rats were perfused with a mixture of Triton X-100 and glutaraldehyde, then the cytoskeleton was observed by transmission electron microscopy. In osteoblasts of the control group, thick bundles of microfilaments ran parallel to the long axis of the cells immediately below the cell membrane adjacent to the osteoid layer. In contrast, in the osteoblasts of the PGE2-administered group, the external morphology was changed to an asteroid or cubic shape, and thick bundles of microfilaments immediately below the cell membrane adjacent to the osteoid were not observed, although microfilament fibres, with a diameter of 5-6 nm, were observed in the cytoplasm.