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植酸酶在肉仔鸡消化道内环境下活性变化的体外研究 总被引:2,自引:0,他引:2
本研究在体外条件下对肉仔鸡消化道内pH环境以及蛋白质水解酶对黑曲霉植酸酶活性的影响进行了研究。结果表明,该植酸酶为酸性植酸酶,最适pH为5.5。该植酸酶对pH环境和蛋白质水解酶较为敏感。当环境pH远离其最适pH时其活性迅速下降,且大部分酶活损失发生在30 min内,然后趋于稳定。在pH3.0和pH6.0条件下,加入胃蛋白酶和胰酶后,植酸酶活性亦进一步迅速降低,然后趋于稳定,但与胃蛋白酶相比,胰酶对植酸酶活性的影响更大。从植酸酶在14、28和42日龄肉仔鸡胃和小肠稳定性的研究可以看出,植酸酶在胃存留率分别为42%、40%和49%,在小肠内的存留率仅19%。植酸酶在胃内的稳定性好于小肠,小肠内环境不利于植酸酶存活。植酸酶活性受肉仔鸡消化道pH和蛋白酶的影响较大,这可能是影响植酸酶作用效果的主要因素之一。 相似文献
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本研究旨在获得对胃蛋白酶和胰蛋白酶具有耐受性的植酸酶转基因猪成纤维细胞系.本研究首先检测了转植酸酶基因的酵母发酵液分别经不同浓度、pH2.0的胃蛋白酶和不同浓度、pH7.0的胰蛋白酶处理后的酶活残余量;然后采用流式细胞术筛选了慢病毒转染的阳性猪成纤维细胞,并进行鉴定.结果表明,酵母粗酶液经胃蛋白酶和胰蛋白酶处理后,残留酶活分别保持在70%和80%以上;包装后的慢病毒滴度为3.75×107,经流式细胞术筛选的转基因细胞阳性率为1.2%,PCR和RT-PCR结果表明,植酸酶基因已整合到基因组上,且该基因在转录水平上表达.本研究为制备植酸酶转基因细胞系提供了一种快速有效的方法,为转基因猪的培育奠定了基础. 相似文献
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以自筛选得到的1株黑曲霉为试验菌株,经固态发酵获得了较高活性的酸性β-甘露聚糖酶。以此酶粉为样本,在相应的pH条件下测定分析其他酶系的活力表现。测定此酸性β-甘露聚糖酶的最适反应pH及最适反应温度,并对其酸稳定性及对胃蛋白酶和胰酶的抗降解作用也进行了特定分析。结果发现,该酶系中除了含有高活性的酸性β-甘露聚糖酶,还含有酸性蛋白酶、木聚糖酶和羧甲基纤维素酶(CMCase)等多种酶活。在pH 2~6,此酸性β-甘露聚糖酶表现出很好的活力,最适酶促反应pH约在3.5;在酸性缓冲液(pH 2.8)中40℃保温8 h,酸性β-甘露聚糖酶的酶活几乎没有损失。在胃蛋白酶环境中(pH 2.8)40℃保温5 h,此酸性甘露聚糖酶表现出非常好的抗降解能力,在胰酶环境中(pH 7.5)40℃保温5 h,酶活力损失不超过20%,在实际生产中具有很广的应用前景。 相似文献
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植酸酶和嗜酸乳杆菌是重要的饲料添加剂,为获得产植酸酶的嗜酸乳杆菌菌株,克隆了大肠杆菌植酸酶基因,构建表达载体并转化嗜酸乳杆菌,对重组嗜酸乳杆菌进行发酵产酶并测定所产酶液的酶学性质,进一步研究重组嗜酸乳杆菌的耐酸性及植酸酶液的抗蛋白酶活性。结果表明:重组嗜酸乳杆菌发酵24 h植酸酶活性为984 U/mL,植酸酶的最适催化pH为4.5,最适催化温度为60℃。重组嗜酸乳杆菌在pH 2.0~4.5有一定的耐酸性,在pH 2.0条件下2 h的存活率为76.4%。植酸酶液用胃蛋白酶处理160 min后植酸酶液剩余85%的相对酶活,用胰蛋白酶处理160 min后剩余29%的相对酶活。上述研究结果为重组嗜酸乳杆菌后续应用研究提供了重要依据。 相似文献
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《国外畜牧学(猪与禽)》2020,(3)
适宜植酸酶发生水解反应的pH范围、对胃蛋白酶的耐受性和水解反应的速度是成为具有可靠的磷基础值(matrix values)和超剂量特性的高效植酸酶的选择标准。 相似文献
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通过将胃蛋白酶和大肠杆菌转基因植酸酶以不同的配比混合,及调节植酸酶溶液的酸度,研究了胃蛋白酶和酸度变化对植酸酶活力的影响,结果表明:胃蛋白酶对植酸酶的活力没有影响,且酸度变化也不会破坏植酸酶的活性。 相似文献
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反刍动物能很大程度上依靠瘤胃微生物来消化利用饲料中的植酸盐,但目前国内有关瘤胃微生物植酸酶的研究报道较少.本文对瘤胃微生物植酸酶的主要来源和活性进行了综述分析,发现主要有5种瘤胃细菌能分泌植酸酶,其中,反刍兽新月形单胞菌(Selenomonas ruminantium)分泌的植酸酶活性最高(199.1~703.6 U·mL-1);根据酶促反应的最适pH和催化机理,可将瘤胃微生物植酸酶分别归类为酸性植酸酶和半胱氨酸磷酸酶植酸酶;根据植酸酶水解植酸时的立体专一性,发现瘤胃微生物植酸酶中可能同时存在3-植酸酶和5-植酸酶2类植酸酶.最后本文论述了瘤胃微生物植酸酶酶促反应动力学特性,发现反刍兽新月形单胞菌植酸酶的最适pH为4.0~5.5、最适温度为50~55℃、对植酸和ATP表现出较强的活性;埃氏巨形球菌植酸酶的最适pH为5,0、最适温度为60℃、仅对植酸表现出活性. 相似文献
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《现代畜牧兽医》2021,(3)
试验研究不同条件对植酸酶水浴耐热性的影响。分别稀释4种植酸酶酶活力40、20、10、2 U/mL,测定80℃和85℃水浴5 min的耐热性。结果表明,稳定性强的植酸酶受酶浓度的影响较小,稳定性较差的植酸酶受影响较大,当处理液酶活力低时,耐热性结果较高。取3种植酸酶样品,分别使用缓冲液Ⅰ、缓冲液Ⅱ、水为耐温稀释缓冲液,测定85℃水浴5 min耐热性,结果表明:缓冲液Ⅰ作为稀释缓冲液测定的耐热性结果最高,其次是缓冲液Ⅱ,水作为稀释缓冲液时测定的耐热性结果最低。取3种植酸酶样品,分别在pH值5.5和5.0缓冲体系中测定85℃水浴5 min耐热性,结果表明,植酸酶在与最适pH值相近的条件下进行耐热性处理,测定的耐热性结果相对较高。研究表明,本试验的3种条件对水浴法测定植酸酶耐热性的结果均有影响,制定检测标准时需要明确测定条件。 相似文献
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Beran GW 《Preventive veterinary medicine》2008,86(3-4):198-207
When early people made their appearance, zoonotic infectious diseases were already waiting, but epidemic diseases did not appear in human history until people began to live in large numbers under conditions of close contact, mainly during the last 10,000 years. Disease has decimated urban populations, conquered armies, and disrupted society. The focus here is on (1) the plague of Athens and the Black Death; (2) smallpox, influenza, and rabies; (3) avian influenza prion diseases, and foot & mouth disease; and (4) emerging and re-emerging diseases. All have veterinary public health associations. In Athens, Greece, in 430 BC, when the Spartans ravaged the countryside, hordes crowded into Athens so that orderly movements, space in which to live, and adequate supplies of food became impossible. Crowding of any population fosters disease transmission; chaos and disorder enhance it all the more. Out of northern Egypt came a terrible plague from across the Mediterranean Sea. The identity of the plague of Athens remains unsure, but the well-considered conclusion is Rift Valley Fever, a mosquito borne, viral zoonosis. The Black Death, also called the Plague, raged in Asia for centuries. In 1347, the Black Death was brought by a ship out of Asia to Sicily. The scenes of devastation were repeated throughout Europe, with 90% or more of the people dying in city after city. Influenza, too, has been a cause of periodic human epidemics, but the great pandemic of influenza occurred in the last months of World War I. In the years of highest occurrence, more than half the world's population became clinically infected. If veterinary public health had been born earlier, it could have led to elucidating the epidemiology of influenza and the plagues of Athens, Europe, and Asia. In turn, smallpox had also caused continual tragedy. In 1796, Edward Jenner began to harvest pustules of cowpox from children or infected cows and inject them into susceptible children. In 1980, the World Health Organization declared that smallpox had been eliminated from the world. Rabies, though, still strikes terror. A number of animal diseases, broadly termed emerging and re-emerging diseases, need surveillance because they have the potential to impact human health. From late in 2003 to 2007, the highly pathogenic H5N1 influenza virus in poultry infected at least 121 people and caused 62 deaths in four countries. The prion diseases, too, all have very high numbers in concentrated contacts. To control these diseases, veterinary public health is essential, with diagnosis, epidemiological surveillance, clinical manifestations, and prevention as primary measures. 相似文献
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Dekker A Dercksen D Snoep J van Wuyjckhuise L 《Tijdschrift voor diergeneeskunde》2007,132(18):695-701
On 26th of july 2007 a new case of bluetongue was notified in the Netherlands and on 2nd of august 2007 foot-and-mouth disease was diagnosed in Surrey, England, which raised the threat of having both infections simultaniously in one area. Bluetongue and foot-and-mouth disease have a different pathogenesis, but symptoms may resemble each other at a later stage of infection. The pathogenesis and possible clinical symptoms of both infections are discussed and illustrated with pictures. 相似文献
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在动物的异常行为中以刻板行为最为常见,而咽气癖又是马最常见的口部刻板行为之一。作者就咽气癖在生理方面和心智方面对马体产生的影响、行为基础、诱因的研究进展及常见的防治措施进行综述。 相似文献
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