首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 203 毫秒
1.
以稻草和麸皮为主要原料,在室温条件下(温度不定)通过单因素筛选出康氏木霉固态发酵产纤维素酶的最佳条件,对氮源、接种量、麸皮添加量、含水量、发酵时间和初始pH值进行研究,结果表明,室温条件下的最佳发酵条件:氮源为尿素,添加量3%,接种量2%,稻草麸皮比7:3,营养液添加量150%,初始pH值3.0,发酵时间72 h,此时,羟甲基纤维素酶和滤纸酶活性最高。  相似文献   

2.
对枯草芽孢杆菌B.subtilis Kpg所产纤维素酶的酶学性质进行研究,确定该纤维素酶的最佳温度和最适pH,并进行固体发酵麸皮试验,验证Kpg纤维素酶的实践效果。试验以3,5-二硝基水杨酸酶活测定法为基础,通过改变纤维素酶的反应温度和pH环境,确定最适反应温度和最适pH环境。为研究其实际降解能力,将枯草芽孢杆菌Kpg添加到麸皮中,在37℃环境中发酵6d。结果显示,枯草芽孢杆菌Kpg纤维素酶的最适反应温度为60℃,此时纤维素酶活性最大为108.45U/mL;反应液最适pH值为6.0,此时纤维素酶活性为97.72U/mL;在两者最适条件共同作用下,纤维素酶活性为113.58U/mL。发酵试验结果显示,枯草芽孢杆菌Kpg能够显著降低麸皮中的纤维素含量(P0.05),同时显著提高发酵麸皮中的真蛋白含量(P0.05)。枯草芽孢杆菌Kpg表现出的酶学性质符合发酵微生物选育的标准和特征,为生物饲料的开发和应用提供数据参考。  相似文献   

3.
枯草芽孢杆菌Pab02产纤维素酶活性的研究   总被引:8,自引:0,他引:8  
试验主要对目前饲料领域应用广泛的枯草芽孢杆菌进行产纤维素酶能力筛选及发酵优化条件的研究,为枯草芽孢杆菌Pab02开发成微生态制剂及生产纤维素酶提供理论依据。通过羧甲基纤维素钠培养基筛选分离到具有产纤维素酶能力的枯草芽孢杆菌Pab02。通过分析初始pH、发酵温度和发酵时间对枯草芽孢杆菌Pab02产纤维素酶活性的影响,得出最佳初始pH为8.0、发酵温度为37℃、发酵时间为48h。在该条件下发酵液酶活达到358.751u/mL酶液,比优化前提高了2.1倍。  相似文献   

4.
本试验采用L9(34)正交试验设计,对崂山奶山羊瘤胃真菌进行体外培养,通过木聚糖酶和羧甲基纤维素酶的测定,筛选出以玉米秸秆为发酵底物的最佳发酵条件(N源、接种量、培养基起始pH值、发酵温度),并按筛选出的发酵条件对玉米秸秆、花生蔓、地瓜蔓和麸皮不同发酵底物的产酶活性进行比较。试验结果表明,木聚糖酶活力最优发酵条件N源为(NH4)2-SO4,接种量5mL,发酵起始pH值为5,发酵温度35℃,产酶最高的发酵底物为秸秆。羧甲基纤维素酶的最优发酵条件N源为(NH4)2SO4,接种量15mL,发酵起始pH值为7,发酵温度39℃。  相似文献   

5.
为了研究里氏木霉以水稻秸秆为原料产生纤维素酶的发酵条件,试验前期首先利用单因素试验对影响里氏木霉发酵生产纤维素酶的生产条件进行研究,找出三个对发酵影响最大的因素,即温度、初始pH值和溶氧;接着通过响应面分析方法对选出的发酵条件进行优化。结果表明:发酵温度为30℃,发酵pH值为4.77,发酵过程中溶氧为50%,纤维素酶活可达93.73 IU/mL。  相似文献   

6.
滤纸法测定饲用纤维素酶酶活的研究   总被引:1,自引:0,他引:1  
本文采用滤纸法研究了影响饲用纤维素酶酶活测定的因素.结果表明:在37℃、pH 5.5条件下,滤纸法测定纤维素酶酶活的适宜波长是540 nm,DNS添加量为2 mL,沸水浴显色时间为5 min,显色后吸光值在15~90min内保持稳定.  相似文献   

7.
不同培养条件对纤维素酶产量和活力影响的研究   总被引:2,自引:0,他引:2  
本试验采用均匀设计U_(12)(12~(10))研究影响生产纤维素酶的五大因素(温度、水分、初始pH值、底物粗纤维水平、培养时间),试图找出培养条件最佳组合,取得最高酶产量和酶活力.结果表明:当底物粗纤维含量为40%、初始pH7.5,加水4倍时,在26—31℃条件下培养45h,获得最大酶产量26mg/g和CMC酶活力20mg/g,h.  相似文献   

8.
秸秆液态发酵中纤维素酶活的研究   总被引:1,自引:0,他引:1  
采用摇床液体发酵试验方法,利用产纤维素酶菌株对秸秆进行混合发酵并进行滤纸酶活性、羧甲基纤维素酶活性测定,从而确定该混合菌株的最优产酶条件。结果表明,最优培养基组成中秸秆和麸皮的混合比例为5∶1,硫酸铵添加量为1.4%,白腐真菌、康宁木霉接种量均为3%,接种时间间隔为48h,pH为7.0,摇床培养温度28℃。  相似文献   

9.
山羊瘤胃内容物菌群中分离得到的一株产纤维素酶菌株T15,采用3,5-二硝基水杨酸法(DNS法)进行优化。对菌株培养基成分碳源、氮源和金属离子进行优化时发现,6 g/L的葡萄糖为碳源和5 g/L的牛肉膏为氮源时,产生酶活力达到最高。培养基中添加0.03 mol/L的Ca~(2+),对菌株产生纤维素酶有促进作用。在最优发酵培养基成分为基础,对菌株T15的发酵培养温度、培养时间、培养pH条件和接种量等四因素、三水平进行正交试验,该菌株的产纤维素酶最优发酵条件:以9 mL为接种量,培养基pH值7,培养温度35℃和培养时间40 h,其产生酶活力达到26.76 U/mL;其中培养时间、接种量、培养温度、和培养基酸碱条件对菌株发酵产纤维素酶影响依次增大。  相似文献   

10.
本试验研究了绿色木霉3.3711液体发酵产纤维素酶条件及酶性质,结果表明,最适的产酶条件为:以玉米秸粉(爆破)为碳源,以硫酸铵为氮源,pH5.0,接种量5%,摇床转速150r/min,温度28℃,培养时间144h。酶作用的最适条件为:温度45~50℃,pH4.5~5.0;在45℃以下,pH3.5~6.0比较稳定。  相似文献   

11.
试验选用96头平均体重14.82 kg左右的杜×长×大断奶仔猪,随机分成4组,每组3栏,每栏8头(公母各半)。对照组饲喂基础日粮,试验1、2、3组分别添加1%80目白术、0.2%白术多糖和1%微米白术。试验期30 d。结果表明:在生长性能方面,与对照组相比,1%微米白术添加组可显著提高日增重(P0.05)、降低饲料增重比和腹泻率,而且效果优于1%80目白术组和0.2%白术多糖组,在肠道形态和肠道微生态区系方面,与对照组相比,日粮添加1%80目白术、0.2%白术多糖、1%微米白术均可不同程度的提高十二指肠和空肠的绒毛高度,加深十二指肠和空肠的隐窝深度,并且增加肠道微生态区系的多样性,其中以1%微米白术添加组的效果最佳。  相似文献   

12.
Sissay, M.M., Uggla, A. and Waller, P.J., XXXX. Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia. Tropical Animal Health and Production, XXXX. A 2-year abattoir survey was carried out to determine the prevalence, abundance and seasonal incidence of gastro-intestinal (GI) nematodes and trematodes (flukes) of sheep and goats in the semi-arid zone of eastern Ethiopia. During May 2003 to April 2005, viscera including liver, lungs and GI tracts were collected from 655 sheep and 632 goats slaughtered at 4 abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga in eastern Ethiopia. All animals were raised in the farming areas located within the community boundaries for each town. Collected materials were transported within 24 h to the parasitology laboratory of Haramaya University for immediate processing. Thirteen species belonging to 9 genera of GI nematodes (Haemonchus contortus, Trichostrongylus axei, T. colubriformis, T. vitrinus, Nematodirus filicollis, N. spathiger, Oesophagostomum columbianum, O. venulosum, Strongyloides papillosus, Bunostomum trigonocephalum, Trichuris ovis, Cooperia curticei and Chabertia ovina), and 4 species belonging to 3 genera of trematodes (Fasciola hepatica, F. gigantica, Paramphistomum {Calicohoron} microbothrium and Dicrocoelium dendriticum) were recorded in both sheep and goats. All animals in this investigation were infected with multiple species to varying degrees. The mean burdens of adult nematodes were generally moderate in both sheep and goats and showed patterns of seasonal abundance that corresponded with the bi-modal annual rainfall pattern, with highest burdens around the middle of the rainy season. In both sheep and goats there were significant differences in the mean worm burdens and abundance of the different nematode species between the four geographic locations, with worm burdens in the Haramaya and Harar areas greater than those observed in the Dire Dawa and Jijiga locations. Similar seasonal variations were also observed in the prevalence of flukes. But there were no significant differences in the prevalence of each fluke species between the four locations. Overall, the results showed that Haemonchus, Trichostrongylus, Nematodirus, Oesophagostomum, Fasciola and Paramphistomum species were the most abundant helminth parasites of sheep and goats in eastern Ethiopia.  相似文献   

13.
14.
1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.  相似文献   

15.
Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.  相似文献   

16.
Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.  相似文献   

17.
Genetic variations in chromosome Y are enabling researchers to identify paternal lineages, which are informative for introgressions and migrations. In this study, the male‐specific region markers, sex‐determining region‐Y (SRY), amelogenin (AMELY) and zinc finger (ZFY) were analysed in seven Turkish native goat breeds, Angora, Kilis, Hair, Honaml?, Norduz, Gürcü and Abaza. A SNP in the ZFY gene defined a new haplotype Y2C. All domestic haplogroups originate from Capra aegagrus, while the finding of Y1A, Y1B, Y2A and Y2C in 32, 4, 126 and 2 Turkish domestic goats, respectively, appears to indicate a predomestic origin of the major haplotypes. The occurrence of four haplotypes in the Hair goat and, in contrast, a frequency of 96% of Y1A in the Kilis breed illustrate that Y‐chromosomal variants have a more breed‐dependent distribution than mitochondrial or autosomal DNA. This probably reflects male founder effects, but a role in adaptation cannot be excluded.  相似文献   

18.
Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.  相似文献   

19.
The objective of this report was to characterize 20-year changes in proportion of calcium oxalate (CaOx) calculi and struvite calculi in dogs, and associations with breed, age, and sex. In this retrospective study, results of analysis of urinary calculi from dogs were reviewed for specimens received between July 1, 1981, and December 31, 2001. Breed, sex, age, year of submission of the specimen, and mineral type(s) were analyzed statistically. CaOx or Struvite or both were contained in 18,966 of 20,884 (91%) specimens. For both sexes, a 20-year statistically significant increase was observed in the proportion of calculus specimens that contained CaOx. The increase in this proportion was greater in females (1% to 31%) than in males (18% to 82%). From 1998 to 2001, when proportions may have plateaued, the odds of specimens containing CaOx were markedly higher in 18 breeds, markedly lower in 5 breeds, and not significantly different in 13 breeds compared with crossbreds. For both sexes, a 20-year statistically significant decrease was observed in the proportion of calculus specimens that contained struvite. This decrease in proportion was greater for males (79-16%) than for females (97-68%). From 1998 to 2001, when proportions plateaued, the odds of calculi containing struvite were markedly lower in 20 breeds, markedly higher in 1 breed, and not significantly different in 15 breeds when compared with crossbreds. Breed, age, and sex were associated statistically with CaOx or struvite urolithiasis. In conclusion, there appears to have been a long-term increase in the proportion of specimens of canine urinary calculi that contain CaOx as well as a long-term decrease in the proportion of specimens of calculi that contain struvite for both male and female dogs. The rate of change appeared to begin leveling off in the period 1998 to 2001. The recent proportion of dogs with either CaOx- or struvite-associated urolithiasis may depend on breed, age, and sex, and on interactions among these 3 factors.  相似文献   

20.
<正>1.INTRODUCTION Ensuring transportation network security is one Of the most daunting challenges confronting homeland security agencies today.Significant research has been dedicated.To model and analyze the vulnerability of transportation systems,while notably fewer studies propose specific strategies for deploying defensive technologies to safeguard these systems.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号