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171.
172.
The phylogenetic relationships among Erwinia amylovora biovar 4 (the pathogen of bacterial shoot blight of pear in Japan), other biovars of E. amylovora, and Erwinia pyrifoliae were investigated using the sequences of 16S rRNA, gyrB, and rpoD genes. The tested isolates formed two distinct monophyletic groups in the phylogenetic trees constructed based on the gyrB gene, rpoD gene, or a combination of the three genes: group 1 contained E. amylovora biovars 1, 2, and 3; group 2 contained E. amylovora bv. 4 and E. pyrifoliae. This phylogenetic analysis showed that E. amylovora bv. 4 was more closely related to E. pyrifoliae than to other biovars of E. amylovora. The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under the accession numbers AB242876 to AB242925.  相似文献   
173.
Invasion of apple fruit by Erwinia amylovora from fruit-bearing twigs through the abscission layer at fruit maturation was examined. Erwinia amylovora (ca. 105 cfu) tagged with bioluminescence genes from Vibrio fischeri was deposited in artificial wounds on fruit-bearing twigs of apple trees grown in a containment greenhouse on September 22, 27, or October 5, 2004. On October 22, 176 apples were harvested and cut horizontally in half. The upper halves were stamped on plates of selective medium, and the lower halves were flooded with iodine solution to assess maturity. All fruit were symptomless and fully mature. The pathogen was recovered from 19 (10.8%) apples. The result showed that if at least ca. 105 cfu of E. amylovora are present in fruit-bearing twigs at the time of fruit maturation, the bacteria can pass through the abscission layer into the fruit, even though the mature fruit lack symptoms.  相似文献   
174.
The solubility of skeletal muscle myofibrillar proteins in water was examined. The solubility of the proteins was found to be sensitive to ionic strength and pH of the solution. At the ionic strength of less than 12 mM and neutral pH, more than 80% of myofibrillar proteins were solubilized. Heating at a temperature of more than 70°C was required for the proteins to retain their solubility. The solubility of freeze‐dried protein powder prepared from water‐soluble myofibrillar proteins was also examined, and it was found that addition of trehalose and heating were essential for re‐solubilization in water. Amino acid composition of water‐soluble myofibrillar proteins was found to be almost the same as that of myofibrillar proteins.  相似文献   
175.
The objective of this grazing study was to determine the herbage mass, nutritive value and palatability of five grass weed species ( Eleusine indica (L.) Gaertn, Paspalum thunbergii Kunth, Digitaria ciliaris (Retz.) Koeler, Setaria glauca (L.) Beauv. and Echinochloa crus-galli (L.) Beauv. var. crus-galli ) as feeds compared with six forage cultivars ( Lolium perenne L., two Lolium multiflorum cultivars and three Echinochloa crus-galli (L.) Beauv. cultivars). The herbage mass of weed species, with the exception of S. glauca , was most prevalent in August. The total amounts of herbage mass of weed species (except E. indica ) were close to those of the Lolium cultivars, but lower than those of the E. crus-galli cultivars. During the summer, weed species (except E. crus-galli var. crus-galli ) contained favorable levels of total digestible nutrients (TDN), crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF) and mineral contents, and exhibited adequate calcium (Ca):phosphorus (P) ratios of 1:2. All weed species had the recommended ratios of potassium (K):(Ca + [magnesium] Mg) < 2.2:1. By autumn, the summertime levels of nutritive values (TDN, CP, ADF and NDF) in the weed species had severely deteriorated, in contrast with those of the forage cultivars. However, they maintained satisfactory mineral content levels and Ca:P and K:(Ca + Mg) ratios (with the exception of E. indica with poor Ca:P ratios and E. crus-galli var. crus-galli with poor P content and Ca:P ratios). All weed species were acceptable to cattle, although there were some differences in palatability among the species.  相似文献   
176.
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.  相似文献   
177.
Black lesions on shoots of European pear trees observed in an orchard in Yamagata Prefecture in May 2007 were suspected to be caused by a bacterial pathogen. The surface of the colonies isolated on a high sucrose medium did not have the crater morphology that is characteristic of E. amylovora bvs. 1–3, and a specific DNA fragment was amplified from the isolates in the PCR using the EprpoD primer set. The partial sequences of the 16S rRNA gene placed the isolates in the genus Erwinia. The isolates differed serologically from E. amylovora biovars and E. pyrifoliae in an Ouchterlony double-diffusion test although their bacterial properties suggested that they are closely related to E. amylovora biovars and E. pyrifoliae. In a DNA–DNA hybridization test, the relatedness between the isolates and E. amylovora biovars or E. pyrifoliae did not exceed 70% level, indicating that they are independent species. Thus, the isolates belongs to the genus Erwnia but are not E. amylovra or E. pyrifoliae. After succulent pear shoots were injected with bacterial suspensions (109, 108, 107 and 10cfu/ml) of the isolates, lesions formed with 109 and 10cfu/ml, but the disease incidence with 10cfu/ml was much lower than with E. amylovora and E. pyrifoliae. Virulence of the present isolates is thus thought to be very weak. On the basis of these results, we consider that this is a new shoot disease of European pear. In the 2007 season, all affected trees were pulled out after harvest. No symptoms have been observed in field surveys since the fruitlet season in 2007.  相似文献   
178.
A 21-month-old Thoroughbred colt showed continuous diarrhea and developmental retardation for 7 months, and was thereafter subjected to euthanasia for necropsy and laboratory examinations. At necropsy, the cecal and colonic mucosae were diffusely rough and hyperemic. Histopathologically, the mucosa and submucosa were edematous and were infiltrated by numerous lymphocytes and macrophages. Meanwhile, three morphological types of Brachyspira antigen-containing spirochetes were found to be numerous in the crypts and in the mucus layer over the epithelium in the cecal and colonic lesions. They were frequently observed in intercellular gaps and in the cytoplasm of degenerative epithelial cells, and in the lamina propria, particularly in cavities around blood vessels. These invasive intestinal spirochetes might be one of pathogens inducing colitis and diarrhea in horses.  相似文献   
179.
Studies of equine intestinal spirochetes have long focused on intestinal contents alone, but intestinal spirochetosis has been reported recently in a 21-month-old Thoroughbred colt in Japan. To define the clinical and pathological significances of intestinal spirochetosis in several horses, an epizootiologic survey with histologic, immunohistochemical, and ultrastructural methods was conducted for Brachyspira antigen-containing intestinal spirochetes in 12 diseased or injured Thoroughbred horses, aged from 35 days to 17 years. Brachyspira antigen-containing spirochetes were found in 7 of 12 horses (58.3%) and were more frequent in the cecum than in other parts of the bowel. It was not clear whether the infection was clinically related to diarrhea or dysentery, but histopathology revealed a close association between the bacterial infection and epithelial hyperplasia. Crypt epithelium consisted mainly of goblet cells and showed frequent mitosis throughout its length. Inflammatory cells and congestion were also present. There were numerous spirochetes in the crypts, and some invaded the cecal and colonic epithelia and underlying lamina propria. Ultrastructurally, the spirochetes were divided into 4 types. Three types were identified in degenerative epithelial cells or intracellularly. Brachyspira antigen-containing intestinal spirochetes invading the mucosa were capable of causing epithelial hyperplasia in the cecum and colon in the horses. The findings in this study will increase awareness of the importance of intestinal spirochetosis and may also be helpful for diagnosis and treatment of this condition.  相似文献   
180.
Floral initiation of a wild strawberry strain, Fragaria chiloensis CHI-24-1, is strongly induced by a 24 h day-length (DL) treatment for 40 days consisting of natural daylight and continuous lighting at night by an incandescent lamp. To use the characteristics of floral initiation in CHI-24-1 as a genetic resource for breeding of cultivated strawberries, the photoperiodic reactions of sexual and asexual reproductive growth under various temperature conditions should be clarified. For that purpose, we examined: (1) floral initiation, inflorescence emergence and runner production seasons of CHI-24-1 plants grown under natural climatic conditions in an open field at the Faculty of Agriculture, Kagawa University and (2) the effects of various DLs and temperatures on floral initiation and runner production of CHI-24-1 plants. When the CHI-24-1 plants were grown under natural conditions, the floral initiation, inflorescence emergence and runner production were observed, respectively, in late autumn, spring, and from spring to autumn. Floral initiation of CHI-24-1 plants was induced strongly by 24 h DL at mean temperatures greater than 20 °C. The maximum floral initiation rates were 90% in the parent plant and 94% in the daughter plants, which were linked by runners to the parent plant. The floral initiation of the daughter plants occurred under 20, 22, and 23 h DL at mean temperatures greater than 20 °C, but not for the parent plants. Floral initiation was induced in 100% of the parent plants by the 8 h DL and the lowest mean-temperature conditions. Results of those experiments indicated that CHI-24-1 was an absolute long day plant having critical DL of about 20 h at mean temperatures greater than 20 °C, even though it was a June-bearing strawberry plant. In addition, CHI-24-1 was a facultative short-day plant at mean temperatures of less than 15 °C.  相似文献   
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