CR1aa-卵丘细胞共培养牛体外受精卵的卵裂率及囊胚率

牛卵母细胞用5％CS的TCM－199培养液体外成熟培养（IVM）22h；以BO液＋咖啡因作精子获能处理1.5h；BO液＋BSA的培养液体外受精（IVF）5h；受精卵（含卵丘细胞）用5％CS的CR1aa培养液在5％CO2、955空气、38.5℃、饱和湿度的培养环境中体外培养（IVC）7－8d，结果受精卵裂率为72.4%（56.3%－81.0%），囊胚率23.7%(12.5%-40.9%）。     

Limitations in the exploitation of N-phenylcarbamates and N-phenylformamidoximes to control benzimidazole-resistant Venturia nashicola on Japanese pear

The efficacy of N -phenylcarbamates and N -phenylformamidoximes against benzimidazole-resistant strains of Venturia nashicola was tested experimentally in Japanese pear orchards. Both compounds gave effective control when applied in an orchard where highly benzimidazole-resistant strains were predominant. However, unsatisfactory control was observed in an orchard where the fungal population was dominated by fungal strains with intermediate or weak benzimidazole resistance. Strains resistant to N -phenylcarbamates and N -phenylformamidoximes were widely distributed in Japanese pear orchards, suggesting that effective use of these compounds to control benzimidazole-resistant strains of V. nashicola would not be practicable. Increased sensitivity to N -phenylformamidoximes in highly benzimidazole-resistant isolates was shown to be controlled by a single chromosomal gene, but progenies that were highly resistant to both a benzimidazole fungicide and a N -phenylformamidoximes appeared in crosses between parents resistant to each fungicide alone. Similar strains were also found in pear orchards, and this'double resistance'was shown to be heritable.     

Comparison of the functions of the barley nicotianamine synthase gene HvNAS1 and rice nicotianamine synthase gene OsNAS1 promoters in response to iron deficiency in transgenic tobacco

Barley ( Hordeum vulgare L.) nicotianamine synthase gene ( HvNAS1 ) expression in barley is strongly induced by Fe deficiency in the roots and rice ( Oryza sativa L.) nicotianamine synthase gene ( OsNAS1 ) expression in rice is induced by Fe deficiency both in the roots and in the shoots. In dicots, NAS genes are not strongly induced by Fe deficiency, and they function to maintain Fe homeostasis. Rice OsNAS1promoter::GUS or barley HvNAS1promoter::GUS was introduced into tobacco ( Nicotiana tabacum L.) and tissue specificities and systemic regulation of their expression were compared. A split-root experiment revealed that the HvNAS1 promoter exhibited functions similar to those of Fe-acquisition-related genes in tobacco roots, suggesting that this promoter responded to certain Fe-deficiency systemic signals and to the Fe concentration in the rhizosphere. The HvNAS1 promoter might harbor a type of universal system of gene expression for Fe acquisition. However, the OsNAS1 promoter did not respond to local application of Fe to the roots and induced GUS activities in mature leaves in response to Fe deficiency. This promoter might possess numerous types of cis -acting sequences that are involved in Fe metabolism.     

Survival and Fluctuation in Density of Myrothecium roridum in Mulberry Field Soil

The density of Myrothecium roridum increased in field soil from June to October and decreased from February to April in 1996–1998. The fluctuation in density of M. roridum in the surface soil was affected by the average temperature. In the greenhouse, mulberry leaves were infected by conidia that splashed from soil artificially infested with conidia of M. roridum at 10³ or more conidia/g soil. Disease incidence on mulberry increased when soil was amended with the fallen leaves and when mulberries were planted densely in soil artificially infested with a high conidial density of M. roridum. Received 9 December 1999/ Accepted in revised form 21 July 2000     

<Emphasis Type="Italic">Pseudomonas syringae </Emphasis>Strains Are Classified into Five Groups by Comparing DMA Homology at the <Emphasis Type="Italic">hrp </Emphasis>Neighboring Regions

Previously, we classified Pseudomonas syringae strains into at least three groups (I, II and U) by comparing DNA homology at the hrp cluster and its neighboring regions (Inoue and Takikawa 1999). However, heterogeneous strains remained in the undetermined group (group U). We further classify group U, using pvs. syringae and coronafaciens as references. Comparison of restriction sites for regions of each pathovar revealed distinct differences. By using probes from the two pathovars, comparisons of DNA homology at the regions separated two additional distinct groups (III and IV) from group U. Therefore, P. syringae strains are classified into at least five groups. Received 4 November 1999/ Accepted in revised form 27 January 2000     

Effects of fasting and refeeding on plasma concentrations of leptin, ghrelin, insulin, growth hormone and metabolites in swine

The effects of nutritional status, such as fasting and refeeding, on leptin and ghrelin secretion in swine were examined. The swine (n = 4) were fasted for 54 h and plasma hormone levels were measured before, during and after fasting. Plasma leptin and insulin concentrations began to decrease 12 and 6 h into the fasting period, respectively (P < 0.05), and maintained a low level for the remaining period of fasting. Plasma leptin and insulin returned to the pre‐fasting value 6 and 12 h after refeeding, respectively. Plasma ghrelin concentrations showed a nocturnal periodicity during the fasting period; it increased nocturnally at 36 and 42 h into the fasting period (P < 0.05). Plasma growth hormone levels did not show any remarkable changes during the fasting. Plasma glucose levels showed a modest fall during fasting and significantly decreased (P < 0.05) at 24 h into the fasting period, returning to pre‐fasting levels after refeeding. Plasma nonesterified fatty acid levels increased (P < 0.05) at 12 h into the fasting period and returned to the pre‐fasting level 6 h after refeeding. These results indicate that plasma leptin, insulin and ghrelin play an important role in maintaining energy homeostasis in swine. The plasma ghrelin did not continuously increase, but showed nocturnal periodicity during fasting. This may suggest that ghrelin is also involved in physiological processes other than energy homeostasis.     

Decrease in stearic acid proportions in adipose tissues and liver lipids in fatty liver of dairy cows

Samples of liver and perirenal, mesenteric and subcutaneous fat were collected from 16 sick necropsied dairy cows to evaluate the fatty acid profiles in the hepatic and adipose tissues associated with advanced fatty liver or hepatic lipidosis. Hepatic triglyceride and eight fatty acids were measured in the hepatic and adipose tissues. Six cows had more than 3% triglyceride on fresh weight in their livers and were classified as having fatty liver. Stearic and linoleic acid proportions in the liver decreased markedly with increased hepatic triglyceride levels, while the proportion of palmitic and oleic acids increased. The most striking fluctuations in hepatic lipidosis were manifested as decreased stearic acid in the adipose tissues including subcutaneous fat with the trend of decreasing stearic acid. Palmitic acid was elevated in hepatic and perirenal fat in fatty liver cows. In instances of advanced hepatic lipidosis, palmitoleic acid increased in only subcutaneous fat and not in perirenal or mesenteric fat. In addition to the proportions of hepatic fatty acids in fatty liver, this study also clarified the fluctuations observed in the profiles of fatty acids of the adipose tissues in cows with advanced hepatic lipidosis, particularly the decline in the proportions of stearic acid.     

Genotyping of infectious bronchitis viruses isolated in Japan during 2008−2019

Seventeen isolates of infectious bronchitis virus (IBV) were obtained from various prefectures of Japan during 2008–2019 and genetically analyzed. The IBV isolates were classified into six genetic groups, based on phylogenetic analysis of the S1 gene. The S1 genotypes were distinguishable by a newly developed restriction fragment length polymorphism (RFLP) method using three endonucleases, Hae II, Hpa I, and Fok I. Moreover, the isolates were classified into four genetic groups, based on phylogenetic analysis of the S2 gene. However, novel genetic groups based on a combination of S1 and S2 genotypes, which were undetected previously, were confirmed in this study, indicating that various recombinant IBV strains were prevalent in poultry in Japan.