Advanced Materials Research Vols. 343-344

Abstract: The mammalian target of rapamycin（mTOR）is a kind of Ser/Thr kinase in mammalian cells. It can recruit and integrate input signals from nutrients, growth factors, energy and environmental stress to regulate cell growth and proliferation via different cellular processes. This study uses the fetal fibroblasts of Inner Mongolia Cashmere goat (Capra hircas) to prove that the mTOR plays a critical role in formation of the cell cytoskeleton structure. The mTOR kinase activity was inhibited in Inner Mongolia Cashmere goat fetal fibroblasts (GFb) after treatment with CCI-779 (temsirolimus), an mTOR specific inhibitor for 48 h. The results showed that GFb cells were sensitive to CCI-779. GFb cells morphology and its cytoskeleton structure changed under confocal laser scanning microscopy stained with the Fluorescent phalloidin (50µg/ml, Phalloidin-FITC5282) which combines with F-actin. In summary, mTOR signaling pathway was proved to be functional in GFb cells and acts as a key regulator to form cell structure. The Morphological results indicated that perhaps the synthesis of microfilament or organization of cytoskeleton was disrupted in GFb cells when mTOR was inhibited.

Abstract: The morphological, physiological and biochemical characteristics of Saccharomyces boulardii were studied for the preparation of highly active yeast. The optimal condition of the flask culture including inoculum size, culture temperature, pH value, were investigated separately. The results showed that S.boulardii was asporogenous and had better heat tolerance and acid tolerance growing well at 37°C and pH 2.0. We also found that thermal death temperature was 55~56°C and S.boulardii is well ethanol-tolerant, for the highest concentration of ethanol that S.boulardii can tolerate was 20%. The optimal culture conditions in a flask culture was YEPD medium with 50ml/250ml medium volume, natural pH, 5% inoculum size, 32°C culture temperature, 160 r/min shaker speed, and 24 hours cultivation period. Under these conditions, suspension was diluted 10 times and the optical density at 600 nm was up to 0.85.

Abstract: Glucose, xylose and L-arabinose were released from corn fiber by dilute acid hydrolysis. The ability of a Candida tropicalis strain to ferment glucose and xylose in corn fiber hydrolysates to produce single cell protein has been examined. The crystalline L-arabinose can be prepared from the fermentation supernatant. The L-arabinose retention rate and biomass protein production by the yeast grown on corn fiber hydrolysate were studied under various culture conditions. The optimal volume of the broth, inoculum size, temperature, initial pH and shaker speed for retention rate of L-arabinose and growth of the strain were 30ml broth in 250ml capacity flask, 4% (v/v), 26°C, 4.0 and 180r/min, respectively. Retention rate of L-arabinose was increased by such conditions to 89.26% and cell dry mass to 13.9g/L, respectively. These values corresponded with high biomass protein and crystalline L-arabinose.

Abstract: Candida rugosa can produce lipoprotein lipase by fermentation in the medium on a rotary shaker, the optimal medium compositions were determined as, the optimum pH was 6.0, the contant was 25ml, the inoculum age of strain was 24h, the inoculation was 10%,the rotation speed was 200r/min and the strain was cultured 27h at 28°C.Under the optimum cultivation conditions, the maximum enzyme activity reached 121.65U/L.The result of enzyme properties showed, the optimum temperature and pH were 45°C and 7.5 separately.

Abstract: This study aimed to investigate the effects of pyruvate and lactic acid on the earlier development of porcine embryos. 5.56 mmol/L glucose in culture medium (NCSU-23) was replaced with 0.2 mmol/L pyruvate and 5.7 mmol/L lactic acid, namely mNCSU-23. Parthenogenetic embryos and nuclear transferred embryos were transferred into NCSU-23 or mNCSU-23 medium according to the experimental design. Parthenogenetic embryos and nuclear transferred embryos were evaluated for the numbers of 5-8 cells stage on Day 2. Blastocyst rates and the numbers of nuclei in the blastocyst were determined on Day 6. From the results, we observed a higher proportion of the embryos reaching 5-8 cells stage at 48h post-activation in mNCSU/NCSU treatment than control during the first part of in vitro culture(IVC) (P < 0.05). In addition, we also observed that the rates of blastocysts formation in mNCSU/NCSU treatments on Day 6 were significantly higher than other treatments, with mNCSU-23/mNCSU-23 treatment having the lowest rates of blastocysts formation on Day 6 (P < 0.05). Our results have demonstrated that replacing glucose with pyruvate and lactic acid during the first part of IVC may be beneficial to the development of the porcine embryos and stepwise culture system(mNCSU-23/NCSU-23) was optimal.

Abstract: As an important source of food ingredients, it is necessary for soybean detection in foods because it was reported as one of the “big 8” food allergens. In this report, a PCR-based method was developed enabling the detection of even small traces of potentially allergenic soybean traces in food products. Soybean-specific primer was designed based on Gly m Bd 28K, one of the major allergens in soybean. The assay was applied to a wide range of food matrices and the detection limit was 0.01% (100ppm) for spiked peanut and whole milk samples, while it was 0.001% (10ppm) for skim milk, wheat and mung bean samples. It seems enough for soybean allergen detection in food matrices according to the threshold of soybean.

Abstract: This study was designed to investigate tellurium bioleaching from the unique independent low-grade tellurium ores containing tetradymite, joseite, pyrite, chalcopyrite, silica, and a minor amount of dolomite, which is the first discovered scattered element deposit in the world. For the bioleaching, the tellurium extractions from the low-grade ores by with and without the adapted bacteria of acidophilic Thiobacillus ferrooxidans were examined. The effects of pH, pulp density, and temperature for bioleaching were studied systematically. After 20 days of bioleaching at 30°C, an 80 % of the tellurium was extracted in laboratory study. Leaching kinetics indicated that diffusion through the product layer was the rate controlling process during tellurium bioleaching, and the relative activation energies during tellurium bioleaching stage was calculated to be 34.75 kJ/mol.

Abstract: In this study, we aimed to detect the single nucleotide polymorphism (SNPs) of the chicken PRKAG3 gene and discern the potential association with meat quality traits. A total of 240 meat-type quality chickens were screened by using single-strand conformational polymorphism analysis (SSCP) and DNA sequencing. Two SNPs (g.1744G>C and g.3207A>G) were identified in chicken PRKAG3 with medium polymorphism (0.25C were significantly associated with water content, crude protein, and crude ash (P<0.05/0.01). The SNP genotypes g.3207A>G were significantly associated with water content, and crude protein (P<0.01). The results suggested that PRKAG3 gene is potential major genes or is in close linkage disequilibrium with the QTL affecting meat quality traits in this population of chickens.

Abstract: Surface modification of poly(vinylidene fluoride) (PVDF) membrane was accomplished by the adsorption of ferric hydroxide sol to impove its hydrophilicity. The adsorption curves of the membranes were analyzed by weight measurements, and the typical results showed a two-platform character in low concentration. The effects of the adsorption time, the ferric hydroxide sol concentration, the test temperature, as well as the water cleaning time on the adsorption amount were observed. Attenuated total reflection-Fourier transform infrared spectroscopy (ATR/ FTIR) analysis showed that the adsorption of ferric hydroxide sol on poly(vinylidene fluoride) microporous membranes (PVDFMM) is effective. The membranes hydrophilic performance was represented by water contact angle measurements. The water contact angles changes from the virgin 128^°to the lowest value 81.90^° in the range of 0~0.10 mol/L ferric hydroxide aqueous solution. The results indicated that ferric hydroxide sol can be immobilized on the PVDF films by adsorption, and the membrane hydrophilic performence increases with the increase of the adsorption amount of the ferric hydroxide sol onto the PVDF membrane surface.

Abstract: The effect of sodium citrate on the metabolic flux distributions in the middle and late periods of L-valine production by Corynebacterium glutamicum XV0505 was obtained. It was shown that when sodium citrate (2.0 g/L) was added into the initial fermentation culture medium, the metabolic flux of Embden-Meyerhof-Parnas (EMP) route decreased from 96.43 to 91.13, and the metabolic flux of Hexose Monophophate (HMP) route increased from 3.56 to 8.87, and the metabolic flux flowing to L-alanine and acetate was decreased by 21.1% and 32.4%, respectively. Meanwhile, the metabolic flux of biosynthesis route of L-valine was increased by 10.74%. Therefore, sodium citrate can change the metabolic flux distribution in the key nodes of biosynthesis route of L-valine, decrease the generation of byproducts, and increase the metabolic flux in the biosynthesis route of L-valine.