Histopathological characterization of the skeletal myopathy in rasH2 mice carrying human prototype c-Ha-ras gene     

Tsuchiya T  Okada M  Sakairi T  Sano F  Sugimoto J  Takagi S 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2005,67(5):481-489

A skeletal myopathy is found in approximately 100% of rasH2 mice. To confirm detailed features of the rasH2 skeletal myopathy, the biceps femoris, diaphragm, triceps brachii, gastrocnemial (types I and II fiber-mixed muscles) and soleus muscle (type I fiber-dominant muscle) obtained from male rasH2 and non-transgenic littermates aged 10-13 and 34 weeks were examined. Variations in the muscle fiber size, early-scattered degeneration/necrosis and regeneration of muscle fibers were detected in 10-13-week-old rasH2 mice. The severity of the above muscular lesions was more prominent in older rasH2 mice. These lesions were noted in the type II myofiber dominant muscles (biceps femoris, triceps brachii and gastrocnemial). NADH-TR stain clearly demonstrated a disorganized intermyofibrillar network and necrotic change in muscle fibers. No specific morphological changes, like rod structure or tubular aggregation seen in some types of myopathy, were noted in Gomori trichrome and NADH-TR stains in the rasH2 mouse like in many types of muscular dystrophy. Electronmicroscopically, occasional muscle fiber degeneration/regeneration, invaded phagocytic cells, indistinct Z-band suggesting excessive contraction and dilatation of the sarcoplasmic reticulum were observed. In summary, the skeletal myopathy occurring in rasH2 mice is consistent with muscular dystrophy characterized morphologically by progressive degeneration and regeneration of myofibers. The myopathy is confined to the type II myofiber predominant muscles and is not associated with any pathognomonic lesions. These characteristics will provide us with a useful model for research in muscular dystrophy of diverse myofibers.  相似文献   

Rwt4 , a wheat gene for resistance to Avena isolates of Magnaporthe oryzae , functions as a gene for resistance to Panicum isolates in Japan     

Vu Thi Bich Hau  Kenji Hirata  Jiro Murakami  Hitoshi Nakayashiki  Shigeyuki Mayama  Yukio Tosa 《Journal of General Plant Pathology》2007,73(1):22-28

Rwt4 (synonym of Rmg1), a temperature-insensitive gene for resistance to Avena isolates of Magnaporthe oryzae, was identified in wheat cultivar Norin 4 in a seedling assay. The significance of Rwt4 was evaluated using flag leaves of wheat cultivars. At high temperature, Norin 4 was completely resistant to Avena isolate Br58, while Chinese Spring, a noncarrier of Rwt4, was susceptible. Genetic analysis of F₂ plants derived from Norin 4 × Chinese Spring indicated that the resistance of flag leaves of Norin 4 to the Avena isolate is conditioned by a single major gene. Segregation analysis of F₃ seedlings derived from the F₂ plants showed that the major gene is actually Rwt4. These results suggest that Rwt4 is effective against Avena isolates throughout the growth stages. Furthermore, screening of Pyricularia isolates from various hosts suggested that Panicum isolates are possible carriers of the corresponding avirulence gene, PWT4. Segregation analyses of F₂ and F₃ seedlings showed that Panicum isolates actually carry PWT4, and, therefore, that Rwt4 is also effective against Panicum isolates. On the other hand, none of the Oryza, Setaria, Triticum, and Lolium isolates tested was a carrier of PWT4. The significance of this finding is discussed from the viewpoint of epidemics of blast disease on wheat.  相似文献   

Reduction in aggressiveness among hybrids between host-specific pathotypes of Magnaporthe oryzae is caused by reduced ability to overcome adult resistance at the level of penetration     

Jiro Murakami  Vu Thi  Bich Hau  Shigeyuki Mayama  Yukio Tosa 《Journal of General Plant Pathology》2006,72(5):284-291

A genetic cross between a Triticum isolate (pathogenic on wheat) and a Setaria isolate (pathogenic on foxtail millet) of Magnaporthe oryzae yielded several F₁ cultures that were virulent on both wheat and foxtail millet at the primary leaf stage. To estimate whether these cultures survive in nature, they were sprayed onto 1-, 2-, and 3-week-old wheat and foxtail millet. As the age of the inoculated plants increased, the lesion number and size were greatly reduced. The F₁ cultures were almost nonpathogenic on both wheat and foxtail millet at the 3-week-old stage. Cytological analysis revealed that the low pathogenicity of the F₁ cultures on older plants was primarily associated with a reduced ability to penetrate the cuticle. When placed on wounded leaf surfaces, the F₁ cultures produced large lesions on 4-week-old wheat and foxtail millet. These results indicate that hybridization between species-specific pathotypes results in a reduction of aggressiveness. We therefore suggest that, even if such hybrids were produced in nature, they might not survive in the natural environment.  相似文献   

High sensitivity of thymocytes of LEC strain rats to induction of apoptosis by X-irradiation     

Hayashi M  Nagata A  Endoh D  Arikawa J  Okui T 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2002,64(7):597-601

It is known that physical disruption of cell contacts induces apoptosis of thymocytes. When thymocytes from LEC and WKAH rats were incubated in vitro at 37 degrees C for 0-6 hr and then the proportion of apoptotic cells was determined using a flow cytometer, it was found that the percentages of apoptotic thymocytes from both LEC and WKAH rats increased with incubation time and that the proportion of apoptotic cells from LEC rats was significantly higher than that from WKAH rats at each incubation time. The fact that cycloheximide, an inhibitor of protein synthesis, did not show significant inhibitory effects on induction of apoptosis of thymocytes indicates that induction of apoptosis during in vitro cultivation did not require de novo protein synthesis. When thymocytes from LEC and WKAH rats were X-irradiated in vitro at 4 and 8 Gy, the percentages of radiation-induced apoptotic cells increased with post-incubation time after X-irradiation in both LEC and WKAH rat thymocytes and the proportions of apoptotic cells from LEC rats were significantly higher than those from WKAH rat cells at 2 and 4 hr post-incubation after X-irradiation. When thymocytes from LEC and WKAH rats were X-irradiated in the presence of cycloheximide, the induction of apoptosis was substantially inhibited, indicating that radiation-induced apoptosis of thymocytes from LEC and WKAH rats required de novo protein synthesis. The present results showed high sensitivities of thymocytes of LEC rats to induction of apoptosis during in vitro cultivation and by X-irradiation.  相似文献   

Relation between cell‐bound exopolysaccharide production via plasmid‐encoded genes and rugose colony morphology in the probiotic Lactobacillus brevis KB290     

Masanori Fukao  Takeshi Zendo  Takuro Inoue  Nobuo Fuke  Tomoo Moriuchi  Yasuhiro Yamane  Jiro Nakayama  Kenji Sonomoto  Tetsuya Fukaya 《Animal Science Journal》2019,90(12):1575-1580

The probiotic Lactobacillus brevis KB290 is a natural producer of cell‐bound exopolysaccharide (EPS), and the plasmid‐encoded glycosyltransferase genes are responsible for this EPS production. KB290 forms unique rugose colonies inside an agar medium; this characteristic is useful for detecting and enumerating KB290 in the gut or feces. However, the genetic elements associated with this morphology remain unclear. Here, we aimed to investigate the relation between the plasmid eps genes and rugose colony morphology in KB290. The plasmid‐cured mutants formed smooth colonies, and the rugose colony morphology was restored after complementation with the eps genes. The eps genes were successfully cloned and expressed in other L. brevis and L. plantarum strains. In these transformant strains, the presence of the EPS, consisting of glucose and N‐acetylglucosamine, correlated with rugose colonies, indicating that EPS is responsible for rugose colony formation. To the best of our knowledge, this is the first report identifying the genetic factors influencing rugose colonies in Lactobacillus strains. This rugose colony formation may serve as a useful selective marker for KB290 in routine laboratory and research settings and can be used to detect the spontaneous loss of plasmids in this strain.  相似文献   

QTL Analysis for Traits Associated with Feeding Value of Straw in Rice （ Oryza sativa L.）     

DONG Chen-fei CAI Qing-sheng WANG Cai-lin Jiro HARADA Keisuke NEMOTO SHEN Yi-xin 《水稻科学》2008,15(3)

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Myxosporean and microsporidian infections in cultured Pacific bluefin tuna <Emphasis Type="Italic">Thunnus orientalis</Emphasis> in Japan     

Jinyong Zhang  Fei Meng  Hiroshi Yokoyama  Jiro Miyahara  Ikuo Takami  Kazuo Ogawa 《Fisheries Science》2010,76(6):981-990

During the parasitological survey of cultured juvenile Pacific bluefin tuna (PBT) Thunnus orientalis in 2007 and 2008, two myxosporeans and one microsporidian were found. Morphological and molecular analysis showed that the heart-infecting and brain-infecting myxosporeans are identified as Kudoa shiomitsui and K. yasunagai, respectively. This is a new host record for both species. High prevalence of infection (77–100%) with K. shiomitsui was observed in October to December (1–2 months post-transfer to sea cages), whereas only a few fish were infected with K. yasunagai. A microsporidian observed as white “cysts” in the trunk muscle of PBT had a resemblance to Microsporidium seriolae, the causative parasite of beko disease in yellowtail. Phylogenetic analysis showed that the microsporidian from PBT is closely related to but distinct from several other muscle-infecting species such as M. seriolae, Microsporidium sp. RSB, and Microsporidium sp. SH. Additionally, the spore dimension (2.7 × 1.5 μm on average) was remarkably smaller than the others. These results suggest that the present microsporidian is an undescribed species and designated Microsporidium sp. PBT. Prevalence and intensity of infection with Microsporidium sp. PBT reached a maximum of 100% and 20 cysts/fish, respectively. Although pathogenic effects of the two Kudoa species on fish health remain unknown, the microsporidian could be of concern to PBT aquaculture due to unsightly cysts in the musculature, reducing the market value of the fish.  相似文献   

Chondroitin sulfate E downregulates N-cadherin and suppresses myotube formation     

Fumi SATOH  Akihiro SUGIURA  Jiro TASHIRO  Yoshinao Z. HOSAKA  Katsuhiko WARITA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2022,84(4):494

Myogenesis, the formation of muscle fibers, is affected by certain glycoproteins, including chondroitin sulfate (CS), which are involved in various cellular processes. We aimed to investigate the mechanism underlying CS-E-induced suppression of myotube formation using the myoblast cell line C2C12. Differentiated cells treated with 0.1 mg/ml CS-E for nine days showed multinucleated and rounded myotubes with myosin heavy chain positivity. No difference was found between the CS-E-treated group with rounded myotubes and CS (−) controls with elongated myotubes in the levels of phospho-cofilin, a protein involved in the dynamics of actin cytoskeleton. Interestingly, N-cadherin, which is involved in the gene expression of myoblast fusion factors (myomaker and myomixer), was significantly downregulated at both the mRNA and protein levels following CS-E treatment. These results suggest that N-cadherin downregulation is one of the mechanisms underlying the CS-E-induced suppression of myotube formation.  相似文献   

Otolith microstructure of chum salmon <Emphasis Type="Italic">Oncorhynchus keta</Emphasis>: formation of sea entry check and daily deposition of otolith increments in seawater conditions   总被引：1，自引：0，他引：1  

Toshihiko Saito  Toshiki Kaga  Jiro Seki  Tsuguo Otake 《Fisheries Science》2007,73(1):27-37

To apply otolith microstructure to examination of age and growth of juvenile chum salmon Oncorhynchus keta inhabiting coastal waters, formation of otolith increments was investigated for juveniles reared in a seawater aquarium and in net pens. In all otoliths examined, a distinctive check was formed at the time of sea entry of the fish. The deposition of otolith increments after the check was daily for rearing both in the aquarium (57 days) and in the net pens (26 days). Check formation associated with sea entry was also observed in otoliths of juvenile salmon collected 1 km off the coast of Shari, Hokkaido, Japan. Transmitted light observation of otoliths of those fish revealed a transition in otolith increment appearance from dark to light. Otolith Sr: Ca ratio remarkably changed from a low to a high level, coinciding with the transition in otolith appearance. It is suggested that the transition was associated with individual sea entry. This study demonstrated that the check and/or transition associated with sea entry are applicable to a benchmark for otolith increment counts of juvenile chum salmon inhabiting coastal waters.  相似文献   

无纺布法防治光肩星天牛成虫的初步研究   总被引：17，自引：0，他引：17  

张波  白杨  岛津光明  井上二郎 《西北林学院学报》1999,14(1):68-72

利用无纺布培养球孢白僵菌（Ｂｅａｕｖｅｒｉａｂａｓｉａｎａ）和布氏白僵菌（Ｂ．ｂｒｏｎｇｎｉａｒｔｉ）,对无纺布上布氏白僵菌分生孢子的自然扩散能力和发芽率进行测定,在风向西北０．９ｍ／ｓ风速条件下,分生孢子的扩散距离达４０ｍ以上,扩散方向与风向有密切关系。无纺布上布氏白僵菌分生孢子在野外自然林地内的发芽率１９ｄ内达到７０％以上。利用无纺布培养布氏白僵菌后,在网箱内对光肩星天牛Ａｎｏｐｌｏｐｈｏｒａｇｌａｂｒｉｐｅｎｎｉｓ（Ｍｏｔｓｃｈｕｌｓｋｙ）成虫的感染死亡率为６１．１％,在旱柳Ｓａｌｉｘｍｉｔｓｕｄａｎａ林地内防治光肩星天牛成虫可以达到３８％的感染效果  相似文献