Distribution and persistence of emamectin benzoate at efficacious concentrations in pine tissues after injection of a liquid formulation

In an earlier paper the authors reported the creation of a novel emamectin benzoate 40 g litre(-1) liquid formulation (Shot Wan Liquid Formulation). The injection of this formulation exerted a preventative effect against the pine wilt disease caused by the pine wood nematode, Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle, and this effect lasted for at least 3 years. The present study was carried out to show experimentally that the marked effect of this formulation was due to the presence and persistence in pine tissues of sufficient amounts of emamectin benzoate to inhibit nematode propagation. A cleanup procedure prior to quantitative analysis of emamectin benzoate by fluorescence HPLC was devised. The presence of the compound in concentrations sufficient to inhibit nematode propagation in the shoots of current growth and its persistence for 3 years explained the marked preventative effect. Non-distribution of emamectin benzoate in some parts of the lower trunk suggested that the formulation should be injected at several points for large trees in order to distribute the compound uniformly to lower branches.     

Gonadosomatic index and testis morphology of common carp (Cyprinus carpio) in rivers contaminated with estrogenic chemicals

To study the effect of estrogenic chemicals on fish, the gonadosomatic index (GSI = [testis weight/body weight] x 100) and testis histology of mature common carp (Cyprinus carpio) from 2 contaminated sites (Ishizu and Wada rivers, Osaka) and a control site were examined between June 1998 and March 2001. The concentration of nonylphenol, bisphenol A and 17beta-estradiol in the Ishizu river was 3-4 times higher than in the Wada river. In the pre-breeding and breeding seasons, there were no significant differences in body weight among carp from the 3 sites, the body weight of Ishizu river carp being significantly lower (p<0.05) than that of Wada river fish only in the post-breeding season. The GSI and testis weight in fish from the Ishizu river were significantly lower (p<0.05) than in control fish during all phases of gonadal cycle and lower than in Wada river fish in the pre-breeding and post-breeding season. No histological abnormalities were found in the testes of the males examined. Histological observation of the testes revealed a delay in the onset of spermatogenesis in fish from the Ishizu river compared with those from the other sites. These results clearly imply that the estrogenic chemicals in the Ishizu river adversely affect the testis development of the fish.     

Specific Oligonucleotide Primers Based on Sequences of the 16S-23S rDNA Spacer Region for the Detection of <Emphasis Type="Italic">Burkholderia gladioli </Emphasis>by PCR

Specific primers were designed based on the sequences of the spacer region between the 16S and 23S ribosomal DNA (rDNA) for direct, rapid and specific detection of Burkholderia gladioli. These primers were named GLA-f and GLA-r. PCR performed on boiled bacterial suspensions yielded an amplification product of approximately 300 bp. No products from other bacterial species, including B. glumae were amplified, even after complete DNA extraction by the cetyltrimethyl-ammonium bromide (CTAB) method. Using the specific primers designed in this study, the PCR method can detect B. gladioli in plant samples within 6 hr. These data demonstrate the potential of specific PCR for the detection of B. gladioli. Received 10 December 2001/ Accepted in revised form 15 April 2002     

Stock enhancement programme for black sea bream, Acanthopagrus schlegelii (Bleeker), in Hiroshima Bay, Japan: a review

This paper reviews the stock enhancement programme for black sea bream ( Acanthopagrus schlegelii ) in Hiroshima Bay. This bay is one of the biggest production areas for black sea bream in Japan, accounting for about 10% of the total catch of the species in this country in 2004. After intensive fishing pressure caused a drastic decline in the catch of the species in this bay in the 1970s, a stock enhancement programme was conducted in its northern part since 1982 to restore the depleted population. The number of black sea bream juveniles released in 1996 surpassed 9 million, representing the third main species stocked in Japan. Almost 1.4 million of these juveniles were released into Hiroshima Bay. The fast acclimatization of hatchery-reared juveniles released into the bay may have contributed to the recovery of landings in the late 1980s and 1990s. However, this recovery was accompanied by a reduction in the market price of black sea bream. Further studies to assess the effectiveness of the stock enhancement programme as well as the carrying capacity of Hiroshima Bay to maintain the stock of black sea bream at a stable, healthy level are desirable. The necessity of evaluating the secondary effects derived from using a reduced number of breeders as well as finding new markets are suggested.     

Biological roles of monoterpene volatiles derived from rough lemon (<Emphasis Type="Italic">Citrus jambhiri</Emphasis> Lush) in citrus defense

Volatile compounds of plants, including monoterpenes, are a possible source of signal molecules that induce defense systems to protect plants from tissue damage. Volatile compounds from rough lemon leaves were trapped by solid-phase microextraction fibers in sealed vials, and subsequent gas chromatography–mass spectrometry and gas chromatography analyses identified the profile of the major components, mainly various monoterpenes. Among several monoterpenes examined, citral, citronellal, and linalool significantly inhibited the spore germination and hyphal growth of Alternaria alternata. The effect of linalool was fungistatic, while the effects of citral and citronellal were partially fungicidal. Wounding of rough lemon leaves induced a significant increase in release of monoterpenes. The release of linalool was the most abundant and was 14.5 times that of unwounded rough lemon leaves. Unlike the wounding treatment, microbe attack did not significantly change monoterpene releases, and there was statistically no difference found in the peak areas from microbe-treated and untreated leaves. Linalool, limonene, and β-pinene also had insect-repellant effects on wild-type Drosophila melanogaster. Expression patterns of defense-related genes in rough lemon and rice significantly changed after treatment with vapors of monoterpene volatiles. Taking these results together, monoterpene volatiles are likely to play roles in the defense of rough lemon against microbe and insect pathogens.     

Digestive enzyme activities of pancreas and intestinal digesta in streptozotocin-induced diabetic piglets

Six (Landrace × Large White) × Duroc crossbred, castrated weanling piglets were used to evaluate the effect of a streptozotocin (STZ) injection to induce diabetes on the activities of digestive enzymes derived from the pancreas (lipase, amylase, trypsin and chymotrypsin) in the pancreas and intestinal digesta. Fasting plasma glucose after the administration of STZ was maintained at the level of 302–491 mg/dL during this experiment, compared with the level of 89–125 mg/dL in the control group, and they were defined as the STZ‐induced diabetic piglets for about 7 weeks. Although their bodyweight increased in proportion to a quadratic curve (P < 0.0001) during 49 days after the administration of STZ, the growth of the STZ‐induced diabetic piglets was slower compared with the control. The STZ‐injection did not affect the percentage of the pancreas in bodyweight. The administration of STZ in the piglets tended to accelerate the activity of lipase (P = 0.06) and depress the activity of amylase (P = 0.15) or chymotrypsin (P = 0.18), as units/kg bodyweight, in the pancreas. In the case of measurement as units/kg bodyweight, the activities of intestinal digesta in the STZ group showed a tendency to be higher than those in control group, irrespective of the sort of enzymes. In conclusion, STZ‐induced diabetic piglets have a moderate digestive ability and the administration of exogenous digestive enzymes is not necessary when they are used as a diabetic animal model.     

Pinpointing the candidate region for muscular dystrophy in chickens with an abnormal muscle gene

Muscular dystrophies, a group of inherited diseases with the progressive weakness and degeneration of skeletal muscle, contain genetically variable diseases. Though chicken muscular dystrophy with abnormal muscle (AM) has long been known, the gene responsible has not yet been identified. In this study, a resource family for AM was established with 487 F2 individuals and 22 gene markers, including microsatellite and insertion–deletion markers, were developed. The haplotypes were analyzed with these markers for the candidate region of GGA2q described in a previous study. The candidate region was successfully narrowed down to approximately 1Mbp. The region included seven functional genes predicted as the most likely AM candidates.     

Activation with ethanol improves embryo development of ICSI-derived oocytes by regulation of kinetics of MPF activity

Developmental potential of bovine embryos that are not artificially activated after intracytoplasmic sperm injection (ICSI) is generally very low. In this study, we investigated effects of artificial activation with ethanol on kinetics of maturation promoting factor (MPF) activity (p34(cdc2) kinase activity) and development of bovine oocytes following ICSI. Treatment of oocytes with ethanol at 4 h after ICSI improved their first cleavage and further preimplantation development (51% vs. 13%, 14% vs. 4%: treatment with vs. without ethanol, respectively). MPF activity of oocytes was lowered until at least 2 h after ICSI. In oocytes without activation after ICSI, MPF activity temporarily elevated at 6 h after ICSI, whereas this phenomena was not observed in the oocytes treated with ethanol. Furthermore, MPF activity was elevated 20 h after ICSI in oocytes activated with ethanol, whereas this elevation of MPF activity was not shown in oocytes without activation. These results indicate that the stimulus of sperm was sufficient to lower MPF activity of oocytes following ICSI, and moreover the activation treatment of bovine oocytes with ethanol after ICSI served to maintain the low levels of MPF activity until the next cell cycle started.     

Effect of alkali extraction on the lignin monomeric composition inEucalyptus

The effect of alkali extraction on the lignin monomeric composition was examined inEucalyptus camaldulensis andE. globulus by thioacidolysis using extractive-free samples as a control. Results showed that the effect onEucalyptus is different among species and among sample positions in the trunk, although a small amount of lignin is solubilized during the extraction in all samples. In addition, it was proved that lignin extracted by the alkali extraction is not always guaiacyl-rich, probably relating to the original lignin monomeric composition, which depends on the sample species or the sample position in the trunk.