皮革鞣制过程中产生大量有害物质,对环境造成了严重污染。角蛋白酶是一类水解角蛋白的酶,是皮革鞣制中理想的鞣制剂替代品。为了发掘角蛋白酶重要的基因资源,试验从土壤中克隆KerA基因,构建了原核表达载体p ET-22b-KerA,通过热激法转入B...皮革鞣制过程中产生大量有害物质,对环境造成了严重污染。角蛋白酶是一类水解角蛋白的酶,是皮革鞣制中理想的鞣制剂替代品。为了发掘角蛋白酶重要的基因资源,试验从土壤中克隆KerA基因,构建了原核表达载体p ET-22b-KerA,通过热激法转入BL21(DE3)中进行表达并在表达时间上进行了优化,对表达的产物进行Western-blot鉴定,通过Ni2+Sepharose Fast Flow分离纯化了KerA,并通过水解角蛋白验证其活性。结果表明:克隆的KerA基因可以在原核中表达,并具有水解角蛋白的活性。说明基因工程重组手段生产KerA具有可行性。展开更多
Orthokeratology is a reversible technique that temporarily changes the curvature of the cornea with the aim of addressing refractive errors. The United States Food and Drug Administration(FDA) granted approval for usi...Orthokeratology is a reversible technique that temporarily changes the curvature of the cornea with the aim of addressing refractive errors. The United States Food and Drug Administration(FDA) granted approval for using reverse geometry contact lenses to correct myopia without any age restriction. Information from the pre-market applications to the FDA was rated as level Ⅱ evidence. Another unapproved use of overnight orthokeratology is for the prevention of myopic progression. Although orthokeratology is advocated to reduce myopic progression, there are limited long-term studies with substantial evidence of its benefits. Much of this evidence comes from non-robust experimental studies using historical or self-selected controls with relative high dropout rates. Although some positive results have been published in temporarily reducing the myopic refractive error and its progression, the use of these lenses can be associated with serious complications such as microbial keratitis. Microbial keratitis is a potentially vision-threatening adverse response associated with contact lens wear. In fact, contact lens wearhas been shown to be the predominant risk factor of microbial keratitis in some developed countries. Most of the published cases on overnight orthokeratology related microbial keratitis occurred in children or adolescents. Parents considering orthokeratology must make an informed decision about its temporary benefit and its potential for permanent loss of vision. The ophthalmic community should be reminded of the potential complications of orthokeratology.展开更多
文摘皮革鞣制过程中产生大量有害物质,对环境造成了严重污染。角蛋白酶是一类水解角蛋白的酶,是皮革鞣制中理想的鞣制剂替代品。为了发掘角蛋白酶重要的基因资源,试验从土壤中克隆KerA基因,构建了原核表达载体p ET-22b-KerA,通过热激法转入BL21(DE3)中进行表达并在表达时间上进行了优化,对表达的产物进行Western-blot鉴定,通过Ni2+Sepharose Fast Flow分离纯化了KerA,并通过水解角蛋白验证其活性。结果表明:克隆的KerA基因可以在原核中表达,并具有水解角蛋白的活性。说明基因工程重组手段生产KerA具有可行性。
文摘Orthokeratology is a reversible technique that temporarily changes the curvature of the cornea with the aim of addressing refractive errors. The United States Food and Drug Administration(FDA) granted approval for using reverse geometry contact lenses to correct myopia without any age restriction. Information from the pre-market applications to the FDA was rated as level Ⅱ evidence. Another unapproved use of overnight orthokeratology is for the prevention of myopic progression. Although orthokeratology is advocated to reduce myopic progression, there are limited long-term studies with substantial evidence of its benefits. Much of this evidence comes from non-robust experimental studies using historical or self-selected controls with relative high dropout rates. Although some positive results have been published in temporarily reducing the myopic refractive error and its progression, the use of these lenses can be associated with serious complications such as microbial keratitis. Microbial keratitis is a potentially vision-threatening adverse response associated with contact lens wear. In fact, contact lens wearhas been shown to be the predominant risk factor of microbial keratitis in some developed countries. Most of the published cases on overnight orthokeratology related microbial keratitis occurred in children or adolescents. Parents considering orthokeratology must make an informed decision about its temporary benefit and its potential for permanent loss of vision. The ophthalmic community should be reminded of the potential complications of orthokeratology.
