最新刊期
2011 年 第 11 期
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Effect of epidermal growth factor on follicle-stimulating hormone-induced proliferation of granulosa cells from chicken prehierarchical follicles
摘要：The development of ovarian follicular cells is controlled by multiple circulating and local hormones and factors, including follicle-stimulating hormone (FSH) and epidermal growth factor (EGF). In this study, the stage-specific effect of EGF on FSH-induced proliferation of granulosa cells was evaluated in the ovarian follicles of egg-laying chickens. Results showed that EGF and its receptor (EGFR) mRNAs displayed a high expression in granulosa cells from the prehierarchical follicles, including the large white follicle (LWF) and small yellow follicle (SYF), and thereafter the expression decreased markedly to the stage of the largest preovulatory follicle. SYF represents a turning point of EGF/EGFR mRNA expression during follicle selection. Subsequently the granulosa cells from SYF were cultured to reveal the mediation of EGF in FSH action. Cell proliferation was remarkably increased by treatment with either EGF or FSH (0.1–100 ng/ml). This result was confirmed by elevated proliferating cell nuclear antigen (PCNA) expression and decreased cell apoptosis. Furthermore, EGF-induced cell proliferation was accompanied by increased mRNA expressions of EGFR, FSH receptor, and the cell cycle-regulating genes (cyclins D1 and E1, cyclin-dependent kinases 2 and 6) as well as decreased expression of luteinizing hormone receptor mRNA. However, the EGF or FSH-elicited effect was reversed by simultaneous treatment with an EGFR inhibitor AG1478. In conclusion, EGF and EGFR expressions manifested stage-specific changes during follicular development and EGF mediated FSH-induced cell proliferation and retarded cell differentiation in the prehierarchical follicles. These expressions thus stimulated follicular growth before selection in the egg-laying chicken.关键词：Epidermal growth factor;Follicle-stimulating hormone;Granulosa cell;Proliferation;Chicken- 109
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发布时间：2022-01-05 -
Development of an indirect competitive ELISA for simultaneous detection of enrofloxacin and ciprofloxacin
摘要：Modified 1-ethyl-3-(3-dimethylaminopropy) carbodiimide (EDC) method was employed to synthesize the artificial antigen of enrofloxacin (ENR), and New Zealand rabbits were used to produce anti-ENR polyclonal antibody (pAb). Based on the checkerboard titration, an indirect competitive enzyme-linked immunosorbent assay (ELISA) standard curve was established. This assay was sensitive and had a linear range from 0.6 to 148.0 μg/kg (R2=0.9567), with the half maximal inhibitory concentration (IC50) and limit of detection (LOD) values of 9.4 μg/kg and 0.2 μg/kg, respectively. Of all the competitive analogues, the produced pAb exhibited a high cross-reactivity to ciprofloxacin (CIP) (87%), the main metabolite of ENR in tissues. After optimization, the matrix effects can be ignored using a 10-fold dilution in beef and 20-fold dilution in pork. The overall recoveries and coefficients of variation (CVs) were in the ranges of 86%–109% and 6.8%–13.1%, respectively. It can be concluded that the established ELISA method is suitable for simultaneous detection of ENR and CIP in animal tissues.关键词：Enrofloxacin;Ciprofloxacin;Indirect competitive ELISA;Animal tissues- 11
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发布时间：2022-01-05 -
Effect of quantum therapy on pork quality
摘要：In this study the impact of quantum therapy on meat quality of slaughtered pigs was investigated. For this purpose the pigs were treated with different doses of magnet-infrared-laser (MIL) radiation. Animals were divided into four groups according to radiation doses (4096, 512, and 64 Hz, and control without application), which were applied in the lumbar area of musculus longissimus dorsi (loin) at various time intervals prior to the slaughter (14 d, 24 h, and 1 h). Animals were slaughtered and the meat quality was evaluated by determining of pH value (1, 3, and 24 h post slaughter), drip loss, colour, and lactic acid and phosphoric acid amounts. MIL therapy can be used in various fields of veterinary medicine as are surgery and orthopaedics, internal medicine, dentistry, pulmonology, gastroenterology, gynaecology, urology, nephrology, and dermatology. The results achieved showed that MIL radiation used in a short period before slaughter (1 h) can cause a change in the meat quality, as reflected by the non-standard development of pH values, increases in drip loss, and changes of meat colour.关键词：Quantum therapy;Meat quality;Colour;Drip loss;Lactic acid;pH- 11
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发布时间：2022-01-05 -
Involvement of basolateral amygdala GABAA receptors in the effect of dexamethasone on memory in rats
摘要：In this study we investigated whether GABAA receptors of the basolateral amygdala (BLA) interact with the effect of dexamethasone on the retrieval stage of memory. Adult male Wistar rats were bilaterally cannulated in the BLA by stereotaxic surgery. The animals were trained in step-through apparatus by induction of electric shock (1.5 mA, 3 s) and were tested for memory retrieval after 1 d. The time of latency for entering the dark compartment of the instrument and the time spent by rats in this chamber were recorded for evaluation of the animals’ retrieval in passive avoidance memory. Administration of dexamethasone (0.3 and 0.9 mg/kg, subcutaneously (s.c.)), immediately after training, enhanced memory retrieval. This effect was reduced by intra-BLA microinjection of muscimol (0.125, 0.250 and 0.500 µg/rat), when administered before 0.9 mg/kg of dexamethasone. Microinjection of bicuculline (0.75 µg/rat, intra-BLA) with an ineffective dose of dexamethasone (0.1 mg/kg, s.c.) increased memory retrieval. However, the same doses of muscimol and bicuculline without dexamethasone did not affect memory processes. Our data support reports that dexamethasone enhances memory retrieval. It seems that GABAA receptors of the BLA mediate the effect of dexamethasone on memory retrieval in rats.关键词：Basolateral amygdala;Dexamethasone;Muscimol;Bicuculline;Passive avoidance task- 11
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发布时间：2022-01-05 -
Growth rate, catalase and superoxide dismutase activities in rock carp (
Procypris rabaudi Tchang) exposed to supersaturated total dissolved gas摘要：Total dissolved gas supersaturation (TDGS) appears when the pressures of gases in a solution exceed the barometric pressures. TDGS is often caused by flood discharge at dams. It may lead to gas bubble disease (GBD) for fish and biochemical responses of selected fish and other aquatic organisms. The purpose of this study was to determine the impact of long-term TDGS levels on the growth and biochemical responses of rock carp (Procypris rabaudi Tchang) dwelling in the upper reaches of the Yangtze River. Three-year-old rock carp were exposed to TDGS levels at 100%, 104%, 108%, 112%, and 116% for 42 d. Samples were taken every 7 d after the start of the trial in order to determine catalase (CAT) and superoxide dismutase (SOD) activities in gill and muscle tissues. Samples were taken at Days 0 and 42 of exposure to determine growth rate. Little effect was found on growth rate in all treatment groups. SOD and CAT activities varied in different tissues, according to time of exposure and TDGS levels. The biochemical response of fish exposed to TDGS was more obvious in gill tissue than in muscle tissue. Surveys of SOD and CAT activities in different tissues offer important information about the effect of TDGS on the rare fish in the Yangtze River, and may help evaluate the risk to the aquatic eco-environment and aquatic ecosystem in the downstream of the Yangtze River.关键词：Total dissolved gas supersaturation (TDGS);Rock carp (Procypris rabaudi Tchang);Growth rate;Catalase;Superoxide dismutase- 12
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- 9
发布时间：2022-01-05 -
Antioxidants in aqueous extract of
Myristica fragrans (Houtt.) suppress mitosis and cyclophosphamide-induced chromosomal aberrations inAllium cepa L. cells摘要：In this study, freeze-dried water extract from the leaves of Myristica fragrans (Houtt.) was tested for mutagenic and antimutagenic potentials using the Allium cepa assay. Freeze-dried water extract alone and its combination with cyclophosphamide (CP) (50 mg/kg) were separately dissolved in tap water at 500, 1000, 2000, and 4000 mg/kg. Onions (A. cepa) were suspended in the solutions and controls for 48 h in the dark. Root tips were prepared for microscopic evaluation. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) free radicals’ scavenging power of the extract was tested using butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) as standards. Water extract of Myristica fragrans scavenged free radicals better than BHA, but worse than BHT. The extract alone, as well as in combination with CP suppressed cell division, and induced chromosomal aberrations that were insignificantly different from the negative control (P≤0.05). However, cytotoxic and mutagenic actions of CP were considerably suppressed. The observed effects on cell division and chromosomes of A. cepa may be principally connected to the antioxidant properties of the extract. The obtained results suggest mitodepressive and antimutagenic potentials of water extract of the leaves of M. fragrans as desirable properties of a promising anticancer agent.关键词：Allium cepa;Antioxidants;Chromosomal aberration;Cyclophosphamide;Mitotic index- 11
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发布时间：2022-01-05 -
Production of conjugated linoleic acids by
Lactobacillus plantarum strains isolated from naturally fermented Chinese pickles摘要：Naturally fermented pickles harbour many lactic acid bacteria (LAB). Forty-three LAB strains with conjugated linoleic acid (CLA)-producing ability were isolated from three naturally fermented pickle brines. Of these isolates, lp15 identified as Lactobacillus plantarum by API 50 CHL system and full-length 16S rDNA sequence analysis exhibited the highest CLA-producing ability (26.1% conversion) at 48 h in de Man Rogosa Sharpe (MRS) broth in the presence of 100 µg/ml of linoleic acid (LA). Compared to other strains, L. plantarum strain lp15 showed the highest tolerance upon increased levels of LA in the medium, i.e., up to 600 µg/ml. This strain converted about 25% of LA into CLA isomers [predominantly cis-9, trans-11 CLA (9-CLA) and trans-10, cis-12 CLA (10-CLA)], of which 75% was 9-CLA. Interestingly, though the conversion rate of LA into CLA by lp15 remained stable between 100 to 600 µg/ml LA levels in the medium, it dropped sharply at 1000 µg/ml. Taken together, the lp15 strain displayed relatively high LA tolerance with higher conversion rate, which implies that this strain is a valuable candidate for enhancing the CLA content in food-sources like pickles.关键词：Conjugated linoleic acids;Lactobacillus plantarum;Lactic acid bacteria;Pickle;Gas chromatography- 8
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发布时间：2022-01-05 -
Preparation of glucosamine by hydrolysis of chitosan with commercial α-amylase and glucoamylase
摘要：Objective:In order to overcome the defects of chemical hydrolysis approach to prepare glucosamine, an enzymatic hydrolysis method was developed.Methods:Glucosamine was prepared by hydrolyzing chitosan, employing α-amylase initially, and subsequently, glucoamylase.Results:The optimal hydrolyzing conditions were as follows: reaction time, 4 h; pH, 5.0; temperature, 50 °C; and, α-amylase, 80 U/g for the initial reaction. Subsequently, glucoamylase was added in the presence of α-amylase. The optimal reaction conditions were found to be: reaction time, 8 h; pH, 4.5; temperature, 55 °C; and, glucoamylase, 4 000 U/g. The hydrolysates were subject to filtrating, concentrating to about 20% (w/w), precipitating with five volumes of ethanol, and drying at 60 °C for 2 h. The content and the yield of glucosamine in the dried precipitate were 91.3% (w/w) and 86.2% (w/w), respectively.Conclusions:The method developed in this study is a promising option in the preparation of glucosamine.关键词：Glucosamine;α-Amylase;Glucoamylase;Hydrolysis- 11
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发布时间：2022-01-05 -
DNA methylation polymorphism in flue-cured tobacco and candidate markers for tobacco mosaic virus resistance
摘要：DNA methylation plays an important role in the epigenetic regulation of gene expression during plant growth, development, and polyploidization. However, there is still no distinct evidence in tobacco regarding the distribution of the methylation pattern and whether it contributes to qualitative characteristics. We studied the levels and patterns of methylation polymorphism at CCGG sites in 48 accessions of allotetraploid flue-cured tobacco, Nicotiana tabacum, using a methylation-sensitive amplified polymorphism (MSAP) technique. The results showed that methylation existed at a high level among tobacco accessions, among which 49.3% sites were methylated and 69.9% allelic sites were polymorphic. A cluster analysis revealed distinct patterns of geography-specific groups. In addition, three polymorphic sites significantly related to tobacco mosaic virus (TMV) resistance were explored. This suggests that tobacco breeders should pay more attention to epigenetic traits.关键词：Methylation-sensitive amplified polymorphism;Epigenetic modification;Tobacco mosaic virus (TMV) resistance;Flue-cured tobacco- 117
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发布时间：2022-01-05 -
A recessive gene controlling male sterility sensitive to short daylength/low temperature in wheat (
Triticum aestivum L.)摘要：Utilization of a two-line breeding system via photoperiod-thermo sensitive male sterility has a great potential for hybrid production in wheat (Triticum aestivum L.). 337S is a novel wheat male sterile line sensitive to both short daylength/low temperature and long daylength/high temperature. Five F2 populations derived from the crosses between 337S and five common wheat varieties were developed for genetic analysis. All F1’s were highly fertile while segregation occurred in the F2 populations with a ratio of 3 fertile:1 sterile under short daylength/low temperature. It is shown that male sterility in 337S was controlled by a single recessive gene, temporarily designated as wptms3. Bulked segregant analysis (BSA) coupled with simple sequence repeat (SSR) markers was applied to map the sterile gene using one mapping population. The wptms3 gene was mapped to chromosome arm 1BS and flanked by Xgwm413 and Xgwm182 at a genetic distance of 3.2 and 23.5 cM, respectively. The accuracy and efficiency of marker-assisted selection were evaluated and proved essential for identifying homozygous recessive male sterile genotypes of the wptms3 gene in F2 generation.关键词：Heterosis;wptms3;Short daylength/low temperature sensitive male sterility;Molecular mapping;Triticum aestivum- 10
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发布时间：2022-01-05
Biochemistry & Biotechnology
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