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ABSTRACT:   β-galactosidase of the intestine of Tilapia nilotica was purified by ammonium sulfate precipitation, followed by PAPTG-Sepharose 4B affinity chromatography, ethylenediamineetetraacetic acid ion-exchange chromatography, polyexchanger PBE 94 chromatofocusing, and Sephadex G-100 gel filtration. β-galactosidase was found to be a single band when examined by poly-acrylamide gel electrophoresis. The purifications of β-galactosidase were 27-fold from the crude extract. β-galactosidase showed optimum activity at pH 5.0 at 40°C, and was specifically found to be able to hydrolyze p -nitrophenyl β-galactopyranoside. It degrades galactan and agarose, and produces galactose. β-galactosidase was strongly inhibited by Hg2+ and PCMB. β-galactosidase is considered to be secreted by the upper and middle parts of the intestine and most of the activity was detected in the intestinal juice.  相似文献   
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Transgenic mice are essential research tools in developmental biology studies. The 2A peptide allows multiple genes to be expressed simultaneously at comparable levels in somatic cells, but there are no reports of it being used successfully in germ cells. We constructed a Cre/loxP-based conditional vector containing the 2A peptide to significantly enhance the expression of a reporter and target gene from a constitutive promoter in oocytes. Mice with a transgene insertion containing the chicken β-actin promoter, floxed EGFP-polyA cassette, mCherry reporter, 2A peptide and target gene DNA methyltransferase 3A2 (Dnmt3a2) were crossed with TNAP- or Vasa-Cre mice to produce offspring, in which mCherry and DNMT3A2 proteins were highly expressed in oocytes upon Cre-mediated removal of EGFP-polyA. This novel transgenic mouse line based on the 2A expression system can serve as a useful tool for examining gene function during oogenesis.  相似文献   
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The major taste active component, glutamate (Glu), improves the taste of meat. In this study, we investigated the effect of a short‐term high‐protein (HCP) diet on the intramuscular free Glu content to improve the taste of meat. Furthermore, we elucidated how the muscle free Glu content was controlled by the HCP diet. Chicks (14 days old) were fed the control diet or HCP diet for 10 days. Plasma and muscle free amino acid concentrations, and activity and messenger RNA (mRNA) expression of muscle enzymes related to Glu metabolism were determined. Muscle free Glu content was increased (P < 0.01) by 51%. Activity and mRNA expression of glutaminase (GA), which is one of the major Glu‐related enzymes, were significantly decreased (P < 0.05) in the HCP group because of feedback inhibition. The mRNA expression of lysine α‐ketoglutarate reductase (LKR), which is the enzyme involved in lysine (Lys) degradation and Glu production, was significantly increased (P < 0.001) in the HCP group. These results suggest that short‐term dietary HCP feeding is an effective treatment for improving the taste of meat. Furthermore, our results suggest that the free Glu content in muscle is regulated by GA and LKR.  相似文献   
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We collected rectal swabs from dogs in Japan during 2011 to 2014, and canine coronavirus (CCoV) nucleocapsid gene was detected by RT-PCR. The relationship between CCoV infection and the manifestation of diarrhea symptoms was investigated, and a correlation was noted (df=1, χ2=8.90, P<0.005). The types of CCoV detected in samples from CCoV-infected dogs were CCoV-I in 88.9% and CCoV-II in 7.4%, respectively. We retrospectively investigated the seroprevalence of CCoV-I in dogs in Japan during 1998 to 2006. The sera were tested with a neutralizing antibody test. In the absence of CCoV-I laboratory strain, we used feline coronavirus (FCoV)-I that shares high sequence homology in the S protein with CCoV-I. 77.7% of the sera were positive for neutralizing anti-FCoV-I antibodies.  相似文献   
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Seasonal reproductive and lunar-related spawning cycles of the female honeycomb grouper Epinephelus merra inhabiting Okinawan waters were examined by histological observation of ovaries. Gonadosomatic index (GSI) increased beginning in May and peaked in June. Histological observations revealed that many oocytes laden with yolk were present in the ovaries from May to August. From September to October, ovaries were occupied by immature oocytes. These results suggest that the reproductive season of E.   merra lasts for 4 months from May through August in Okinawan waters. When the fish were collected according to the lunar cycle, GSI increased with the approach of the full moon. Oocytes at various development stages were observed from the first quarter to the full moon. Fresh ovulatory follicles were present in the ovaries around the last quarter moon. These results suggest that E.   merra has a lunar spawning cycle and spawns between the full moon and the last quarter moon. Ovarian features of the fish collected around the last quarter moon were different among individuals; some fish had many oocytes at the tertiary yolk stage in the ovaries, while the ovaries of the others were occupied by the oocytes at the peri-nucleolus and the oil droplet stages. This observation suggests that a minor release of eggs occurs in this species before or after a major spawning lunar day. Oocytes at the migratory nucleus and the maturation stages were not observed in any ovarian samples. This may mean that maturation of oocytes is related to the spawning behavior of this species and makes rapid progress in the process of aggregation at the spawning sites.  相似文献   
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The purpose of the present study is to investigate the feasibility of strain analysis using speckle tracking echocardiography (STE) in cats and to evaluate STE variables in cats with hypertrophic cardiomyopathy (HCM). Sixteen clinically healthy cats and 17 cats with HCM were used. Radial and circumferential strain and strain rate variables in healthy cats were measured using STE to assess the feasibility. Comparisons of global strain and strain variables between healthy cats and cats with HCM were performed. Segmental assessments of left ventricle (LV) wall for strain and strain rate variables in cats with HCM were also performed. As a result, technically adequate images were obtained in 97.6% of the segments for STE analysis. Sedation using buprenorphine and acepromazine did not affect any global strain nor strain rate variable. In LV segments of cats with HCM, reduced segmental radial strain and strain rate variables had significantly related with segmental LV hypertrophy. It is concluded that STE analysis using short axis images of LV appeared to be clinically feasible in cats, having the possibility to be useful for detecting myocardial dysfunctions in cats with diseased heart.  相似文献   
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To investigate the ecological importance of the cellulolytic bacterium Fibrobacter succinogenes in fiber digestion, ruminal distribution of F. succinogenes was determined in relation to its phylogenetic grouping. Rumen digesta from wethers and steers fed orchardgrass hay, rice straw or fresh orchardgrass were employed as the materials for the analyses. Orchardgrass hay stem incubated in the rumen was also used. By using total DNA extracted from these materials, population sizes of total F. succinogenes and of four different phylogenetic groups of this species were quantitated through competitive polymerase chain reaction (PCR), and restriction fragment length polymorphism analysis of PCR products targeted the bacterial 16S rDNA. Rumen digesta and ruminally incubated hay stems had a reasonably high population size of F. succinogenes (×107?8/g) that was composed of strains belonging to the phylogenetic groups 1 and 3. The relative abundance of each group was different among the samples; group 1 dominated on the ruminally incubated hay stem and in the rumen of wethers fed fresh orchardgrass, while group 3 was major in the rumen of wethers and steers on hay diet. These results suggest that there could be phenotypic differences among the phylogenetic groups of F. succinogenes, and group 1 dominating on hay stem might contribute to rumen fiber digestion more than the other groups.  相似文献   
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