Changes in fatty acid composition with age and environment in different types of peat profiles in Japan

Fatty acid composition of the crude lipid fraction of peat was investigated using several typical peat profiles in Japan. Fatty acid composition varied with the peat layers accumulated in a peat profile since 32,000 years BP. Deposition of long-range transported volcanic ash tephras also affected the composition remarkably due to the acceleration of decomposition. Fatty acid composition differed among high moor, transitional moor, and low moor peat profiles sampled in several locations in Hokkaido, Japan. The difference in the plants involved in the formation of peat was considered to be a very important factor determining the fatty acid composition. For example, arachidic acid was considered to be a good indicator for the presence of reed, while the percentage of stearic acid tended to be high in the high moor peat profiles dominated by sphagnum. As the fatty acids with a longer chain length were more stable than those with a shorter chain length, the percentage of longer fatty acids (C24 and C26) tended to increase and that of shorter fatty acids (CI4 and CI6) to decrease in the lower peat profiles. The drying of peatland also exerted a similar effect on the fatty acid composition.     

Distribution of benzimidazole-resistant strains of the onion gray-mold neck rot pathogens,Botrytis aclada and Botrytis allii,in Hokkaido,Japan

Botrytis aclada and Botrytis allii, associated with onion gray-mold neck rot and isolated in Hokkaido, were tested for sensitivity to benzimidazole. Of the B. aclada strains, 59% were highly resistant and the remaining 41% were sensitive; all strains of B. allii were sensitive. Resistant strains were widespread in Hokkaido. We analyzed the sequences of the β-tubulin gene of resistant strains and detected the replacement of glutamic acid (GAG) by lysine (AAG) at codon 198. This is the first report of benzimidazole resistance in B. aclada. This study revealed a difference in fungicide sensitivity between the two Botrytis species.

     

Biosafety assessment of transgenic poplars overexpressing xyloglucanase (AaXEG2) prior to field trials

We performed biosafety assessments of transgenic poplars prior to field trials. Constitutive expression of the Aspergillus aculeatus xyloglucanase in Populus alba increased the cellulose content and specific gravity of its stem, the leaves of which were visibly greener, thicker, and smaller than those of the wild-type plant. Although the young transgenic poplars grew faster than the wild type in a growth chamber, there was no distinguishable difference in growth between the poplars when they were placed in a special screened greenhouse. Allelopathic tests showed that the transgenic poplars do not produce harmful substances. Based on all the biosafety assessments and the scientific literature on poplar species, we came to the conclusion that transgenic poplars probably do not disturb the biological diversity of the surrounding environment, even when they are submitted to field trials.     

Direct Extraction of Volatiles of Rice During Cooking Using Solid-Phase Microextraction

An apparatus that allows extraction and enrichment of flavor volatiles of rice during cooking using solid-phase microextraction (SPME) was designed and tested in the Japanese rice cultivar Akitakomachi. Because it is a solvent-free technique, no solvent contaminants were extracted during sampling. This technique enables one to place the fiber of SPME in the effluent of the flavor volatiles of the rice during cooking and it can also be used for simultaneous extraction of those volatiles in the course of the cooking process. Therefore, variations in the composition and amount of volatile compounds of rice during cooking can be determined. The overall flavor volatiles of rice during cooking have been analyzed by using this SPME method. Compounds that have been previously highlighted as flavor volatile markers, such as volatiles from oxidative degradation of lipids, products from thermal decomposition, and fatty acids existing in rice, were extracted directly by SPME in conjunction with this apparatus.     

In vitro lecithinase activity and sensitivity to 22 antimicrobial agents of Clostridium perfringens isolated from necrotic enteritis of broiler chickens

Viable Clostridium perfringens ranging from 10(5) to 10(8) g-1 was detected in all of 88 intestinal content specimens of necrotic enteritis in broiler chickens. In vitro lecithinase activity and sensitivity to 22 antimicrobial agents were determined for the 88 isolates. The activities of lecithinase in the culture filtrate of isolates were estimated to be 0.5 to 4.0 AE ml-1 as alpha-antitoxin equivalent. With reference to antimicrobial activity penicillins and cephazolin showed excellent activity and no resistance; peptides, of the agents used as growth promoters, showed that all except bacitracin had low minimum inhibitory concentration levels (1.6 micrograms ml-1 or less) against this organism; polyethers of monensin, salinomycin and lasalocid were generally adequate in low concentrations while there was a high level of resistance to three tetracyclines in 90 per cent of the strains and all isolates were insusceptible to streptomycin of the aminoglycoside antibiotics.     

Tissue culture of feline normal mammary gland

To study the growth and morphology of feline mammary epithelial cells in vitro, normal feline mammary tissues as well as cells collected from feline milk were cultured and examined using phase-contrast microscopy and immunohistochemistry. The method employed was a modification of Hiratsuka et al., and was found to be useful for the culture of dissociated feline mammary tissue. Small polygonal cells and large spindle-shaped cells that were positively stained with anti-keratin and anti-actin antibodies formed colonies with a pavement-like structure in culture of mid-pregnant mammary gland. Cultures of involuting mammary gland were composed mainly of small spindle-shaped cells, which were negative for keratin immunostaining and thought to be fibroblasts. Myofibroblasts, which participate in feline mammary carcinogenesis, and show keratin negative, actin positive, were not encountered in the present culture system of normal mammary gland. The cells from milk formed small colonies, but did not grow to reach confluent monolayer.     

Disease Resistance of Tissue-cultured Seedlings of Rhododendron after Treatment with Streptomyces sp. R-5

An endophytic actinomycete, Streptomyces sp. R-5, which had been isolated from a field-grown rhododendron plant, was used to protect rhododendron seedlings in tissue culture from Pestalotia disease caused by Pestalotiopsis sydowiana. R-5 had intense antagonistic activity against P. sydowiana without adversely affecting the seedlings in glass flasks. A suspension of R-5 was spread on the surface of the multiplication medium in glass flasks in which seedlings were growing. Ten days later, the 4th upper leaf of seedlings was inoculated with P. sydowiana and incubated for 14 days. In controls untreated with R-5, substrate mycelia of P. sydowiana grew on all leaves and stems above and below the 4th leaf within 2–3 days of inoculation. Such growth resulted in the wilting death of 54% of seedlings by 14 days. In contrast, only the inoculated leaves turned brown in ca. 90% of seedlings growing on medium treated with R-5. None of these seedlings died. Thus, treatment of the medium surface with R-5 efficiently protects the seedlings from infection by P. sydowiana. Scanning electron microscopy revealed that substrate mycelia of R-5 grew on and beneath the cuticle of leaves of the treated seedlings. Fluorescent microscopy showed that R-5 was also inside the leaves. Received 8 June 2001/ Accepted in revised form 4 July 2001     

Effect of water‐soluble carbohydrate content in orchardgrass pasture on grazing time and rumen fermentation in dairy cows

Two experiments were conducted to clarify the effect of water‐soluble carbohydrate (WSC) content in orchardgrass pasture on the diurnal distribution of grazing time. Six ruminally cannulated, non‐lactating dairy cows were grazed on either of two pastures with different orchardgrass cultivars containing low WSC (LWSC; cultivar: ‘Hokkai 28’) or high WSC (HWSC; cultivar: ‘Harunemidori’). The cows were grazed in morning and evening sessions in experiment 1, whereas the cows were grazed throughout the day in experiment 2. In experiment 1, grazing time of the cows on HWSC was longer than that of the cows on LWSC (P < 0.01). This difference was larger in the morning session than in the evening session (pasture × grazing session: P < 0.05). Effects on herbage intake were similar to those on grazing time. In experiment 2, daily total grazing time was longer for the cows on HWSC than for those on LWSC (P < 0.05). The cows on HWSC spent a longer time grazing than those on LWSC in the morning between 03.00 and 09.00 hours (P < 0.01). The results indicated that prolonged grazing time in the period between dawn and early morning could increase daily herbage intake in cows grazed on pastures of orchardgrass cultivars with high‐WSC content.     

Randomized clinical trial to evaluate the effectiveness of enrofloxacin as a second‐line antibiotic for treatment of acute Escherichia coli mastitis

The objective of the present study was to evaluate the effectiveness of enrofloxacin (ERFX) as a second‐line antibiotic for treatment of acute Escherichia coli (E. coli) mastitis. Forty‐two cows with naturally occurring acute E. coli mastitis were enrolled. On the first day of treatment (day 0), empirically selected antibiotics (oxytetracycline: n = 32, kanamycin: n = 10) were administered. Although systemic signs improved in 10 cows (first‐line group), the signs remained unchanged or worsened in 32 cows on day 1, including two cows that were found dead. The 30 surviving cows were randomly assigned to second‐line groups constituting an ERFX group (n = 19) or a control group (n = 11) that was treated with other antibiotics. Response to each treatment was evaluated by measuring clinical signs from day 0 to day 3, subsequent quarter milk recovery, and the 60‐day survival rate. Appetite on day 3 was significantly better in the ERFX group compared to the control group. No significant differences were observed in the 60‐day survival rate or the subsequent milk recovery between the ERFX group and the control group. Thus, the use of ERFX as a second‐line antibiotic for the treatment of acute E. coli mastitis could induce a rapid appetite recovery.     

5α-Reductase inhibitory compounds produced by polymerization of resveratrol with horseradish peroxidase

To produce 5-reductase inhibitory compounds, resveratrol was enzymatically oxidized in a horseradish peroxidase (HRP)/H₂O₂ system. Ethyl acetate extract of the oxidation products showed strong 5-reductase inhibitory activity with 10%–15% organic solvents in the system, whereas without organic solvent little inhibitory activity was exhibited. The optimum pH of enzymatic oxidation for acquisition of the inhibitory activity was 4.5. The inhibitory compounds were isolated and identified as resveratroltrans-dehydrodimer and resveratrolcis-dehydrodimer by comparing with published nuclear magnetic resonance data. The two resveratrol dehydrodimers have stronger inhibitory activity than natural resveratrol dimers and trimers found inShorea species.