Acute infection of encephalomyocarditis (EMC) virus in Syrian hamsters.     

Y Sugawara  K Hirasawa  M Takeda  J S Han  K Doi 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1991,53(3):463-468

One-month-old Syrian hamsters of the APA and Std: golden strains were inoculated intraperitoneally with 10(5) PFU/head of the D variant of encephalomyocarditis (EMC) virus and examined virologically and pathologically up to 7 days after inoculation. APA hamsters developed apparent hyperglycemia due to pancreatic islet cell damage while Std:golden hamsters did not. Hamsters of both strains showed clear histopathologic changes in the testis with prominent viral replication as well as in the brain, heart and exocrine pancreas. The susceptibility to EMC virus-infection was higher in males than in females and in APA than in Std: golden hamsters.  相似文献   

MCPB-ethyl疏花对富士苹果授粉受精及胚珠发育的影响   总被引：6，自引：1，他引：6  

曹秋芬  孟玉平  横田清  崔贵梅  青華幸二  寿松木章 《果树学报》2003,20(1):8-11

通过在花期用MCPB-ethyl处理,对富士苹果花粉的发芽、花粉管的伸长以及胚珠的发育等进行了形态方面的观察和探讨,以阐明MCPB-ethyl的疏花机制。结果表明,MCPB-ethyl对花粉的发芽及花粉管的伸长没有影响,整个受精过程与对照相同,没有发现异常。但受精后胚乳核只进行了数次分裂便停止生长,此后珠皮、珠心细胞迅速解体。根据以上结果,认为MCPB-ethyl的疏花效果不是通过影响花粉的发芽或花粉管的伸长阻碍受精所致,而是使胚和胚珠的发育停止,形成离层导致了落花。  相似文献   

Preventive effects of CIDR-based protocols on premature ovulation before timed-AI in Ovsynch in cycling beef cows     

Sakase M  Kawate N  Nakagawa C  Fukushima M  Noda M  Takeda K  Ueno S  Inaba T  Kida K  Tamada H  Sawada T 《Veterinary journal (London, England : 1997)》2007,173(3):691-693

Ovsynch is a program developed to synchronize ovulation for timed breeding. In this paper, the authors investigate whether controlled internal drug release (CIDR)-based protocols prevent premature ovulation before timed-artificial insemination (AI) when Ovsynch is started a few days before luteolysis in cycling beef cows. Nine beef cows at 16 days after oestrus were treated with (1) Ovsynch, i.e. gonadotropin releasing hormone (GnRH) analogue on day 0, prostaglandin (PG) F(2alpha) analogue on day 7 and GnRH analogue on day 9 with timed-AI on day 10, (n=3); (2) Ovsynch+CIDR (Ovsynch protocol plus a CIDR for 7 days from day 0, n=3), or (3) oestradiol benzoate (OB)+CIDR+GnRH (OB on day 0 in lieu of the first GnRH treatment, followed by the Ovsynch+CIDR protocol, n=3). In the Ovsynch group (1) plasma progesterone concentrations fell below 0.5 ng/mL earlier (day 5) than in both CIDR-treated groups (2) and (3), where this occurred on day 8. Plasma oestradiol-17beta concentrations peaked on day 8 in the Ovsynch group and on day 9 in both CIDR-treated groups. The dominant follicle ovulated on day 10 in the Ovsynch group and on day 11 in both CIDR-treated groups. Thus, both CIDR-based protocols prevented premature ovulation before timed-AI in Ovsynch when the protocol was started a few days before luteolysis. This reflects the fact that progesterone levels remained high until the beef cattle were treated with PGF(2alpha).  相似文献   

Assessment of rabbit spleen size using ultrasonography     

Takeda Y  Asaoka H  Ueno M  Jimma F  Hidaka M  Shibusawa H  Kaneda K  Saniabadi AR  Hiraishi K  Kashiwagi N 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2007,69(8):841-842

Assessment of spleen size using the ultrasonography has become a standard practice in human. However, the assessment is not established method in experimental animals. To establish the index to assess the spleen size using ultrasonography, we measured the cross-section image of rabbit spleen during endotoxin shock. The image of the cross-section was appeared as triangle, and the height of the triangular image was defined as the spleen index. This spleen index showed strong correlation with the spleen weight. In conclusion, this method is suitable for observation of changes in rabbit spleen size and may reduce the number of rabbit in the longitudinal studies.  相似文献   

Seasonal changes in semen characteristics, composition of seminal plasma and frequency of acrosome reaction induced by calcium and calcium ionophore A23187 in Large White boars     

Murase T  Imaeda N  Yamada H  Miyazawa K 《The Journal of reproduction and development》2007,53(4):853-865

This study attempted to explain the mechanisms regulating boar fertility by examining seasonal changes in semen characteristics, the composition of seminal plasma and responsiveness of sperm acrosomes to Ca(2+) and the Ca(2+) ionophore A23187 (Ca(2+)/A23187). Sperm-rich and sperm-poor fractions were separately collected from 3 mature fertile Large White boars once a month over a one-year period. During the period of study, ambient temperature and relative humidity were recorded for within the stall in which the boars were kept and the semen characteristics, composition of the seminal plasma of sperm-rich fractions, and occurrence of the acrosome reaction in response to Ca(2+) (3 mM)/A23187 (0.3 microM) were examined. The highest mean maximum and minimum ambient temperatures were recorded in August-September, whereas the lowest mean maximum and minimum ambient temperatures were recorded in December and January, respectively. There was a moderate peak in relative humidity from July to October. The lowest percentages of motile spermatozoa and of spermatozoa with intact acrosomes and highest percentage of spermatozoa with abnormal morphology and strongest agglutination were seen in August-September. The total protein and albumin concentrations were lowest in August-September. Testosterone levels increased gradually as day length decreased after the summer solstice (June) and peaked in October-November. The percentage of acrosome reactions in response to Ca(2+)/A23187 was highest with the quickest response in August-September, as shown by the shortest time required for 50% of relative acrosome reactions. The farrowing rates were lowest in these same 2 months. These results suggest that seasonal infertility in Large White boars may be due, at least in part, to a combination of low motility, abnormal morphology including acrosomal abnormality, and early occurrence of the acrosome reaction in response to stimulus, possibly resulting from a decrease in acrosomal stabilizing proteins in the seminal plasma during summer. These changes may be modulated by heat/humidity stress and/or photoperiod-regulated testosterone.  相似文献   

Gene silencing of cyclooxygenase-2 mRNA by RNA interference in bovine cumulus-granulosa cells     

Kobayashi S  Sakatani M  Kobayashi S  Okuda K  Takahashi M 《The Journal of reproduction and development》2007,53(6):1305-1311

Inhibition of specific gene expression using RNA interference (RNAi) is a valuable tool for functional analysis of a target gene. However, there is little information available concerning RNAi for analysis of gene function in relation to the reproductive physiology of follicular cells in ruminants. Thus, the aim of this study was to evaluate the interfering effect of small interference RNA (siRNA) on expression of cyclooxygenase-2 (Cox-2) mRNA and prostagrandin F(2alpha) (PGF(2alpha)) production in bovine cumulus-granulosa (CG) cells. Bovine CG cells were collected from aspirated follicles and cultured. After reaching confluency, two experiments were conducted. In experiment 1, to investigate the effective concentration of siRNA, 0, 100, 250 and 500 pM of Cox-2 siRNA was introduced into the CG cells, respectively. After 24 h, the amount of Cox-2 mRNA expression was measured by RT-PCR and real-time PCR. In experiment 2, to investigate the time required for effective interference of siRNA and Cox-2 activity, 250 pM siRNA was introduced for 0, 3, 6, 12 and 24 h. After culture, the amount of Cox-2 mRNA expression was measured and the culture medium was collected to determine the PGF(2alpha) concentration by enzyme immunoassay. The Cox-2 mRNA expression was not affected by introduction of 100 pM siRNA into CG cells for 24 h, but 250 and 500 pM Cox-2 siRNA significantly reduced the Cox-2 mRNA expression. Moreover, the significant suppressive effect of 250 pM siRNA was observed 6 h after introduction, and the reduction of mRNA expression by RNAi became more obvious over 12 h. On the other hand, the PGF(2alpha) concentration in the culture medium was not significantly different 12 h after siRNA introduction; however, the PGF(2alpha) concentration 24 h after siRNA introduction was significantly decreased compared with the control at the same time point. These results suggest that gene silencing of Cox-2 with siRNA is capable of analyzing the function and expression of specific genes in bovine CG cells.  相似文献   

外源人绒毛膜促性腺激素诱导黑边石斑鱼排卵的研究     

徐文刚  唐永政  张建柏  征矢野清  邹华锋 《广东农业科学》2020,47(4):122-128

【目的】了解外源人绒毛膜促性腺激素(human chorionic gonadotropin,HCG)诱导黑边石斑鱼(Epinephelus fasciatus)排卵的影响。【方法】以成熟的黑边石斑鱼为研究对象,测量其体长、体质量和肥满度后,在2018年7—8月,使用HCG激素(剂量为200 IU/kg或500 IU/kg)注射分别对6尾雌鱼进行成熟诱导。【结果】在200 IU/kg HCG处理中,注射24 h前有5尾雌鱼的卵母细胞处于第三次卵黄球前期阶段;注射48 h后2尾雌鱼出现核移动卵母细胞,1尾雌鱼的卵母细胞为第三次卵黄球后期阶段;注射60 h后1尾雌鱼出现排卵现象,其余5尾雌鱼均为第三次卵黄球后期阶段。在200 IU/kg HCG处理的排卵个体中,注射时其卵母细胞直径为477.0 μm,注射后60 h卵母细胞的直径增加至624.4 μm。此外,经催产、排卵、受精和孵化后共获得总卵数16 906粒,受精率为68.7%,孵化率为43.0%。而500 IU/kg HCG处理的黑边石斑鱼排卵失败。【结论】使用剂量为200 IU/kg的外源HCG激素可诱导黑边石斑鱼成熟且排卵,但为了提高排卵率、受精率和孵化率,其注射剂量和效应时间还需要进一步调节。  相似文献   

Nocturnal/diurnal demand-feeding pattern of yellowtail Seriola quinqueradiata under different keeping conditions   总被引：1，自引：0，他引：1  

Jun Kohbara  Iwao Hidaka  Isao Kuriyama  Mitsushi Yamashita  Masasuke Ichikawa  Kiyoshi Furukawa  Katsumi Aida  F. Javier Sánchez-Vázquez and  Mitsuo Tabata 《Fisheries Science》2000,66(5):955-962

  相似文献   

Species identification method for <Emphasis Type="Italic">Scombrops boops</Emphasis> and <Emphasis Type="Italic">Scombrops gilberti</Emphasis> based on polymerase chain reaction-restriction fragment length polymorphism analysis of mitochondrial DNA     

Shiro Itoi  Noriyuki Takai  Satomi Naya  Keitaro Dairiki  Akira Yamada  Seiji Akimoto  Kiyoshi Yoshihara  Haruo Sugita 《Fisheries Science》2008,74(3):503-510

ABSTRACT:   Gnomefish Scombrops boops and Scombrops gilberti are commercially important fishes in Japan, but these species are often confused in the markets because of their morphological similarity. To identify these two species, we performed nucleotide sequencing and restriction fragment length polymorphism (RFLP) analysis on 16S ribosomal RNA (rRNA) gene and the control region in mitochondrial DNA. Five and 12 nucleotide substitutions were observed between species in the 777-bp 16S rRNA gene and 471-bp control region, respectively. Diagnostic restriction sites for discriminating between S. boops and S. gilberti were found in the 16S rRNA gene, but not in the control region. Polymerase chain reaction (PCR)–RFLP analysis using two enzymes, Eco NI and Mva I, clearly discriminated between S. boops and S. gilberti identified by meristic characters. The PCR–RFLP analysis identified most of the 168 Scombrops young caught in the coastal waters of the Izu and Miura peninsulas as S. boops , suggesting that S. gilberti juveniles are rare in this area.  相似文献   

Effects of Aeration, Alum Treatment, Liming, and Organic Matter Application on Phosphorus Exchange between Soil and Water in Aquaculture Ponds at Auburn, Alabama   总被引：4，自引：0，他引：4  

Kiyoshi  Masuda Claude E.  Boyd 《Journal of the World Aquaculture Society》1994,25(3):405-416

Application of readily-oxidizable organic substrate to laboratory soil-water systems and fish ponds caused anaerobic conditions in bottom soil and water, and concentrations of soluble reactive phosphorus (SRP) increased. Aeration of ponds increased total phosphorus (TP) concentrations by suspending soil particles in the water, but SRP concentrations declined because of increased oxy- genation of bottom water and soil, Alum [Al₂(SO₄)₃·14H₂O] treatment of ponds reduced SRP and TP concentrations in ponds, but the low concentration of alum used, 20 mg/L, had little residual effect on phosphorus concentration. Application of agricultural limestone at 0.2 kg/m² to ponds with soil pH of 5.5 and Ca²⁺ concentration of 5 mg/L did not affect SRP and TP concentration. Unless pond soils were anaerobic at their surfaces, a condition not acceptable in thermally-unstratified fish ponds, soils released little phosphorus to the water. Strong adsorption of phosphorus by soils in intensive ponds with feeding is beneficial, because removal of phosphorus by aerobic soils is a control on excessive phytoplankton growth. In fertilized ponds, phosphorus must be applied at frequent intervals to replace phosphorus removed from the water by soils.  相似文献