Genetic Diversity and Population Structure in the Heavily Exploited Korean Rockfish,Sebastes schlegeli,in Korea

The Korean rockfish, Sebastes schlegeli, is a valuable and intensively exploited species in Korea. We discuss the genetic diversity and genetic structure of four Korean rockfish populations using eight microsatellite loci. In total, 161 different alleles from 138 individuals were observed. Average allele number per locus ranged from 2.5 to 23 and allelic richness varied from 13.38 to 14.63 within a population. Despite a long history of stocking practices, we found very high levels of polymorphism (mean heterozygosity = 0.810), which is comparable to other congeneric species. No significant difference in genetic diversity and molecular genetic variance (F_ST and R_ST) was observed among four local samples (P > 0.1). Little indication of contemporary inbreeding (F_IS= 0.051) or population structure (K = 1) was detected. This absence of differentiation may reflect high levels of gene flow along the coast of Korea. Our study demonstrates that rockfish in Korea should be managed as a single unit. Currently, the species does not appear to be genetically threatened, but the potential for a rapid loss of genetic diversity remains. This information on the genetic characteristics of Korean rockfish populations has important implications for fisheries management and conservation efforts, and will aid in the sustainable exploitation of the fishing resources and the preservation of biodiversity.     

Naturally occurring eastern equine encephalitis in a Hampshire wether.

Eastern equine encephalitis (EEE) was diagnosed (postmortem) in a sheep with clinical signs attributable to a central nervous system disease. The sheep was febrile and initially had front limb incoordination, which progressed to paralysis of both front and hind limbs during a course of 2 days. The sheep maintained an alert attitude with the ability to eat up to the time of euthanasia. The only clinical pathologic abnormalities were neutrophilia and lymphopenia without appreciable leukocytosis, a moderate hyperglycemia, and an elevated creatine kinase. Treatment included hydrotherapy for lowering body temperature, intravenous fluids, thiamine hydrochloride, tetanus antitoxin, antibiotics, and corticosteroids. The only gross lesion at the time of necropsy was a wet glistening surface of the brain (leptomeninges). Microscopically, there was severe nonsuppurative meningoencephalitis, poliomyelitis, and polyradiculoneuritis with mild multifocal neutrophilic infiltration. The EEE virus was isolated from the brain, and subsequent fluorescent antibody testing for EEE was positive on cell culture.     

Contact and fumigant activities of constituents of Foeniculum vulgare fruit against three coleopteran stored‐product insects

The insecticidal activities of materials derived from the fruit of fennel, Foeniculum vulgare, against adults of Sitophilus oryzae, Callosobruchus chinensis and Lasioderma serricorne were examined using direct contact application and fumigation methods. The biologically active constituents of the Foeniculum fruits were characterized as the phenylpropenes (E)‐anethole and estragole, and the monoterpene (+)‐fenchone, by spectroscopic analysis. Responses varied with insect species, compound, dose and exposure time. In a filter paper diffusion test, estragole at 0.168 mg cm^?2 caused 91% mortality to S oryzae adults within 1 day after treatment (DAT), whereas (+)‐fenchone and (E)‐anethole gave over 90% mortality at 2 and 4 DAT, respectively. Against C chinensis adults, all test compounds revealed potent insecticidal activities at 0.021 mg cm^?2 at 2 DAT. Against L serricorne adults at 0.105 mg cm^?2, (E)‐anethole gave 100% mortality at 1 DAT, whereas 90 and 60% mortality at 4 DAT was achieved with estragole and (+)‐fenchone, respectively. In a fumigation test, the test compounds were much more effective against adults of S oryzae, C chinensis and L serricorne in closed cups than in open ones, indicating that the insecticidal activity of test compounds was largely attributable to fumigant action. As naturally occurring insect‐control agents, the F vulgare fruit‐derived materials described could be useful for managing field populations of S oryzae, C chinensis and L serricorne. © 2001 Society of Chemical Industry     

In situ hybridization for the detection and localization of swine Chlamydia trachomatis

Gnotobiotic piglets were inoculated intralaryngeally with swine Chlamydia trachomatis strain R33 or orally with swine C. trachmatis strain R27. Archived formalin-fixed, paraffin-embedded tissues from piglets euthanatized 4-7 days postinoculation were examined by in situ hybridization for C. trachomatis nucleic acid using a nonradioactive digoxigenin-labeled DNA probes that targeted specific ribosomal RNA or omp1 mRNA molecules of the swine C. trachomatis strains. Positive hybridization signals were detected in bronchial epithelial cells, bronchiolar epithelial cells, pneumocytes, alveolar and interstitial macrophages, and jejunal and ileal enterocytes. Chlamydia-infected cells had a strong signal that was confined to the intracytoplasmic inclusions. Positive hybridization signals were not detected in tissue sections from an uninfected control piglet or in C. psittaci-infected sheep placenta. The morphology of host cells was preserved despite the relatively high temperature required in parts of the incubation procedure. The data indicate that in situ hybridization can be used to detect swine C. trachomatis in formalin-fixed, paraffin-embedded tissue specimens.     

Experimental prevention of bitterweed (Hymenoxys odorata) poisoning of sheep

To examine the effects on bitterweed toxicity of dietary factors known to increase thiol concentrations in the body, 36 lambs were fed one of the following diets (12 lambs/diet) for a minimum of 9 days prior to bitterweed administration: diet 1, 10% crude protein; diet 2, 20% crude protein, 0.5% methionine, 0.5% sodium sulfate, and 1,102 IU of vitamin E/kg; and diet 3, diet 2 with 0.5% ethoxyquin hydrochloride added. Four lambs fed each diet were euthanatized prior to bitterweed administration (initial euthanasia group). Four lambs fed each diet were administered bitterweed (0.68% hymenoxon, air-dried basis) at a rate of 0.25% of live weight for 5 consecutive days. The remaining four lambs on each diet served as unchallenged controls. In the initial euthanasia group, diet 2 increased extracellular blood thiol concentrations (1.12 vs 0.94 mg of SH/d1, P less than 0.10), rumen fluid thiol concentrations (4.46 vs 1.88 mg of SH/d1, P less than 0.05), and liver thiol concentrations (263.6 vs 109.3 micrograms SH/g of wet wt, P less than 0.05), compared with diet 1. Ethoxyquin hydrochloride (diet 3) reduced blood thiol concentrations (0.94 vs 1.12 mg of SH/dl, P less than 0.10) and liver thiol concentrations (151.6 vs 263.6 micrograms of SH/g of wet wt, P less than 0.05), compared with diet 2. Kidney thiols were unaffected by treatments.(ABSTRACT TRUNCATED AT 250 WORDS)     

Development of the Cardiac Conducting System in the Chick Embryo

Chick embryos at 3 to 15 days of incubation were examined for the developmet and differentiation of the "four rings" of the heart. It was clarified that nodes and bundles of the impulse conducting system in the adult chicken were derived from these rings. This finding was very important for understanding the cardiac conducting system in birds and mammals.     

Flow cytometric assessment of ethylene glycol monoethyl ether on spermatogenesis in rats

The effects of ethylene glycol monoethyl ether (EGEE) on testicular cell populations in rats were investigated by a flow cytometric method. Rats were administered by gavage with EGEE at the various doses of 0 (saline alone), 100, 200, 400, and 800 mg/kg body weight/day for 4 weeks. The treatment of EGEE caused decreases in the weight of testis and epididymis and in the number of testicular cells. Histopathologically, exfoliation of germ cells into the tubular lumen was observed at the doses of above 200 mg/kg. The treatment of EGEE at the dose of 400 mg/kg caused moderate testicular degeneration. A significant depletion of haploid cells and a disproportionate ratio of diploid and tetraploid cells were observed as determined by flow cytometric analysis. These results indicate that the toxic effect of EGEE on the male reproductive system may be strongly associated with the disproportion of testicular germ cells.     

Histochemical detection of glycoconjugates in the male reproductive system of the horse

Lectins are glycoproteins of plant and animal origin that have the ability to bind specific carbohydrate residues of cell glycoconjugates, particularly in terminal positions. In this study, the binding of lectins, Dolichos biflorus agglutinin (DBA), soybean agglutinin (SBA), Bandeiraea simplicifolia BS-1 (isolectin B4), Triticum vulgaris (WGA), Arachis hypogaea (PNA), and Ulex europaeus (UEA-I), was studied in the reproductive systems of male thoroughbred horses.DBA was detected in the stereocilia of the caput and corpus epididymis, and in the vas deferens. It was weakly detected in connective tissue of the corpus epididymis. Strong SBA staining was seen in epithelial cells in the testis, stereocilia of the corpus and cauda epididymis, and in the vas deferens. There were intense positive reactions for isolectin B4 in interstitial cells in all tissue and serosa of the vas deferens. PNA staining was seen only in stereocilia in the caput and corpus epididymis, and in the vas deferens. Strong WGA staining was seen throughout the testis, except in Sertoli cells, stereocilia, and connective tissue. UEA-I was detected in secondary spermatids, stereocilia, and epithelial cells of the cauda epididymis. These results show that degenerating cells in the testis, epididymal tubules, and vas deferens have differential affinities for lectins, and suggest that lectins play a role in the reproductive system of the horse. The heterogeneity of the lectin staining pattern in the reproductive tubules of adult horses suggests that the carbohydrate composition of each cell type is region specific.     

Efficacy of live virus vaccines against infectious laryngotracheitis assessed by polymerase chain reaction-restriction fragment length polymorphism

The efficacy of four different commercial live vaccines (vaccines A, B, C, and D) against the infectious laryngotracheitis virus (ILTV) was assessed in specific-pathogen-free (SPF) chickens. SPF chickens were vaccinated intraocularly at 6 wk old with ILTV live vaccines and were challenged intratracheally with the N91B01 strain of virulent Korean ILTV 2 wk after vaccination. The immunity against ILTV live vaccines was assessed by the incidence of latent infection by the challenge virus in the chickens' tracheas and trigeminal ganglia, the reisolation rate of the challenge virus, and the clinical signs in the chickens challenged with the N91B01 strain of ILTV. The latent infection in chickens was assessed by nested polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Our data showed that the clinical signs and challenge virus isolation were negative in all chickens receiving four difference commercial ILTV live vaccines. The viral DNA of the vaccine strain, but not that of the challenge virus, was detected in chickens vaccinated with vaccine A by nested PCR-RFLP. The viral DNAs of both the vaccine and challenge strains were detected from chickens vaccinated with vaccines B, C, and D. This study showed that only vaccine A can protect chickens from latent infection with the field virulent ILTV. We speculate that the efficacy of infectious laryngotracheitis live vaccines to protect chickens from latent infection with virulent ILTVs can be assessed by nested PCR-RFLP analysis.