ABSTRACT
The aim of this study was to purify and characterize a keratinase produced by a new isolated Bacillus subtilis KD-N2 strain. The keratinase produced by the isolate was purified using ammonium sulphate precipitation, Sephadex G-75 and DEAE (diethylaminoethyl)-Sepharose chromatographic techniques. The purified enzyme was shown to have a molecular mass of 30.5 kDa, as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The optimum pH at 50 degrees C was 8.5 and the optimum temperature at pH 8.5 was 55 degrees C. The keratinase was partially inactivated by some metal ions, organic solvents and serine protease inhibitor phenylmethanesulfonyl fluoride (PMSF). Sodium dodecyl sulfate (SDS) and ethylene diamine tetraacetic acid (EDTA) had positive effect on the keratinase activity. Reducing agents including dithiothreitol (DTT), mercaptoethanol, L-cysteine, sodium sulphite, as well as chemicals of SDS, ammonium sulfamate and dimethylsulfoxide (DMSO) stimulated the enzyme activity upon a feather meal substrate. Besides feather keratin, the enzyme is active upon the soluble proteins ovalbumin, bovine serum albumin (BSA), casein and insoluble ones as sheep wool and human hair. Calf hair, silk and collagen could not be hydrolyzed by the keratinase.
Subject(s)
Bacillus subtilis , Classification , Enzyme Activation , Enzyme Stability , Peptide Hydrolases , Chemistry , Species Specificity , Substrate SpecificityABSTRACT
<p><b>OBJECTIVE</b>To study viruses infecting Pinellia ternata in China.</p><p><b>METHOD</b>Symptom observation, DAS-ELISA and RT-PCR detection were applied.</p><p><b>RESULT AND CONCLUSION</b>During a survey in early spring, SMV and CMV were both commonly distributed as main viruses infecting P. ternata collected from different areas in China. But DsMV was the virus which infected P. ternate in natural condition. The infection ratio of cultivated P. ternate by SMV and CMV were 71.4% and 14.3% respectively for 21 samples collected from Ningbo, Zhejiang province; 100% and 44.4% for 18 samples from Xiaoshan, Zhejiang province; 61.9% and 33.3% for 21 samples from Hebei province; 50.0% and 41.7% for 12 samples from Anhui province; 16.7% and 16.7% for 12 samples from Sichuan province; 31.3% and none for 16 samples from Beijing. And the infection ratio of 25 wild samples from different areas of China infected by SMV and CMV were both 20.0%.</p>
Subject(s)
China , Cluster Analysis , Cucumovirus , Genetics , DNA, Complementary , Chemistry , Genetics , Mosaic Viruses , Classification , Genetics , Pinellia , Virology , Plant Diseases , Virology , Plants, Medicinal , Virology , Sequence Analysis, DNAABSTRACT
Neuropeptide Y (NPY) is one of the most important orexigenic agents in central regulation of feeding behavior, body weight and energy homeostasis in domestic chickens. To examine differences in the hypothalamic NPY between layer-type and meat-type of chickens, which are two divergent kinds of the domestic chickens in feeding behavior and body weight, we detected mRNA levels of NPY in hypothalamic infundibular nucleus (IN), paraventricular nucleus (PVN) and lateral hypothalamic area (LHA) of these two types of chickens using one-step real time RT-PCR. The meat-type chicken had more food daily (about 1.7 folds) and greater body weights (about 1.5 folds) and brain weights than the layer-type chicken at the age of 14 d. In the meat-type of chicken, NPY mRNA levels of the IN and PVN were significantly greater than those of the LHA, and were not significantly different between the IN and PVN. However, in the layer-type of chicken, NPY mRNA levels were significantly greater in the IN than those in the LHA and PVN, and were not significantly different between the PVN and LHA. In all these hypothalamic regions, the layer-type of chicken had significantly higher NPY mRNA levels than the meat-type chicken did. These results suggest the expression of NPY in the hypothalamus has a type-dependent pattern in domestic chickens.
Subject(s)
Animals , Male , Body Weight , Chickens , Classification , Metabolism , Hypothalamus , Metabolism , Meat , Neuropeptide Y , Genetics , RNA, MessengerABSTRACT
Using the tissue culture technology to achieve the fast propagation of P.ternata and through the photosynthetic characters and yield comparison,two high-yield indivaduals were obtained. The result showed that the coefficent of propagation can get to 1∶6.23 per generation, through 3 month culture the average diameter of the in vitro tuber can get 0.88 cm. P.ternata was a typical shade-plant, of which LCP was only 700?mol?photons/s?m2. Photo-inhibition was observed among all the three leaf-types of P.ternata, and the willow leaf type showed the most obvious photo-inhibition. Both of the light response Pn curve and single tuber weight were significant different among leaf styles. Result for studying the chlorophyll fluorescence parameters showed that all the difference of NPQ, qP and qN among three leaf-types of P.ternata were significant and the difference of potential-photosynthetic productivity among them was significant. The willow leaf style had the strongest light-tolerance capacity.The individuals of T2(peach-leaf type) had the highest Pn and single tuber weight among 11 superior individuals and the individuals of L2(willow-leaf type) showed the strongest light-tolerance capacity. Through 6 month propagation ten thousands in virto tuber of T2 and L2 each were gotten. And after growing in Wenzhou experimental base for one year, the total gross weight of the high-yield individual tuber get to 100kg each.
ABSTRACT
Fermentation conditions for the production of spores of Bacillus mucilaginosus mutant 021120 were optimized through the single factor and orthogonal experiments.The results showed that the biomass and formation of spores were obviously affected by carbonate,followed by nitrogen.Addition of CaCO3 and enhancing air flux notably promoted the formation of spores.The optimal culture medium was composed of 2% starch,0.4% Yeast,0.1% K2HPO4,0.1% MgSO4?7H20 and 0.5 %CaCO3,pH7.5.6% of the inoculum prepared with two-stage extensive culture was inoculated into a 70L fermentor.The fermentation was carried out with 2.0~2.5 vvm of air flux at 32℃ for 38~42h,and the spores of 9.80?108 cfu ml-1 was obtained.Under these optimal fermentation conditions,the capsule was successfully controled and the formation of the spores was effectively improved,thus the satisfying bacteial product was obtained.