过氧化氢驱动的细胞色素P450酶研究进展

细胞色素P450酶在自然界中广泛存在,能催化多种类型的氧化反应,在有机合成和生物化工方面具有重要的应用潜力。尽管大多数P450酶通常需要辅酶和复杂的电子传递体系协助活化氧分子,一些P450酶也可以利用过氧化氢作为末端氧化剂,这极大地简化了催化循环,为P450酶的合成应用提供了一条新的简便途径。本文系统地介绍了几类过氧化氢驱动的P450酶催化体系,包括脂肪酸羟化酶P450SPα和P450BSβ、脂肪酸脱羧酶P450OleTJE、人工改造的羟化酶P450BM3和P450cam突变体、以及基于底物误识别策略的P450-H2O2体系。通过分析催化反应机制,本文探讨了P450-H2O2催化体系在目前存在的挑战和可能的解决途径,并对其进一步应用前景进行了展望。     

维生素C葡萄糖苷的研究现状及发展前景

维生素C葡萄糖苷是卫生署公布认可的美白添加剂之一,利用糖基转移酶的特异性转糖基作用进行生物转化合成是目前维生素C葡萄糖苷的唯一生产途径。对维生素c葡萄糖苷的生产方法进行了讨论,着重阐述了其制备（生物转化合成法）、纯化及结晶三大生产工艺的国内外研究现状,指出国内实现维生素C葡萄糖苷工业化生产的发展方向。     

贵州小型猪肠菌群失调模型的制备

目的 探索小型猪肠菌群失调模型的制备方法.方法 分别采用大黄和氨苄青霉素灌服,通过检测贵州小型猪新鲜粪便中双歧杆菌、乳酸杆菌、肠杆菌、肠球菌的数量,了解其肠菌群变化情况.结果 两种方法都可导致贵州小型猪肠菌群改变.两组相比,大黄组菌群变化速度较快、持续时间较短;氨苄青霉素组菌群变化速度较慢、持续时间较长.结论 两种方法均可制备比较稳定的贵州小型猪肠菌群失调模型,但具体表现不尽相同,应用时可根据需要选择.     

A histological and biomechanical study of bone stress and bone remodeling around immediately loaded implants

Immediate loading(IL)increases the risk of marginal bone loss.The present study investigated the biomechanical response of peri-implant bone in rabbits after IL,aiming at optimizing load management.Ninety-six implants were installed bilaterally into femurs of 48 rabbits.Test implants on the left side created the maximal initial stress of 6.9 and 13.4 MPa in peri-implant bone and unloaded implants on the contralateral side were controls.Bone morphology and bone-implant interface strength were measured with histological examination and push-out testing during a 12-week observation period.Additionally,the animal data were incorporated into finite element(FE)models to calculate the bone stress distribution at different levels of osseointegration.Results showed that the stress was concentrated in the bone margin and the bone stress gradually decreased as osseointegration proceeded.A stress of about 2.0 MPa in peri-implant bone had a positive effect on new bone formation,osseointegration and bone-implant interface strength.Bone loss was observed in some specimens with stress exceeding 4.0 MPa.Data indicate that IL significantly increases bone stress during the early postoperative period,but the load-bearing capacity of peri-implant bone increases rapidly with an increase of bone-implant contact.Favorable bone responses may be continually promoted when the stress in peri-implant bone is maintained at a definite level.Accordingly,the progressive loading mode is recommended for IL implants.     

Intracellular levels of calmodulin are increased in transformed cells

By using Hoechst 33342,rabbit anti calmodulin antibody,FITC-labeled goat anti rabbit IgG and SR101(sulfo rhodamine 101)simultaneously to stain individual normal and transformed cells,the microspectrophotometric analysis demonstrated that 3 markers which represented the nucleus,calmodulin and total protein respectively,could be recognized in individualj cells without interference,The phase of the cell cycle was determined by DNA content(Hoechst 33342),We found that in transformed cells(NIH3T3) tsRSV-LA90,cultured at 33℃ and transformed C3H10T1/2 Cells),the ration of calmodulin to total protein (based on the phases of cell cycle)was higher than that in normal cells (NIH3T3 tsRSV-LA90 cells,cultured at 39℃ and C3H10T1/2 cells)in every cell cycle phase,This ration increased obviously only from G1 to S phase in either normal or transformed cells.The results showed that calmodulinreally increased during the transformation,and its increase was specific.In the meantime when cells proceeded from G1 to S.the intraceollular calmodulin content also increased specifically.     

MYCOLOGY IN CHINA WITH EMPHASIS ON REVIEW OF THE ANCIENT LITERATURE

<正> Ⅰ.Ancient Literature ReviewThe edibility and medicinal use of fungi were known to Chinese ancestors long,long ago.Our fathers recognized and used them as food,as medicine,in agriculture,in industry,for fermentation,etc.Fungi such as common mushrooms,wood ear,jellyfungus(Tremella fusiformis)have been used for food;china root(Poria coccus),ca-     

130例智力低下儿童脆性X检测报告

本文采用脆性 X检测技术对130例先天性智力低下儿童进行了细胞遗传学研究,结果共发现27例具有染色体异常。其中t(5;15)及t(8;12),inv(9)两例核型,经鉴定为世界首报核型;检出5例脆性X综合征,检出率为3.77%,占异常核型的18.5%。 Abstract:The cytogenetic study was made on 130 mentally retarded children with the technique of Fra(X) detection.Among the 27 mentally retarded children with chromosomal abnormalities found in the study,the two karyotypes of t (5;15) and t (8;21),inv(9) were first reported in the literature.of the 130 mentally retarded cases,5 had fragile (X) syndrome (3.77%).The syndrome accounted for 18.5% in the abnormal karyotypes.     

油用向日葵主要农艺性状的遗传分析

对10个油用向日葵品种的主要农艺性状进行遗传分析的结果表明,株高、单株粒数、百粒重、盘径和单株粒重等农艺性状具有较大的遗传率,可以在早代单株选择或直接选择;出苗-现蕾、现蕾-开花、开花-成熟、皮壳率等性状的遗传率较低,应根据各性状间相关关系进行间接选择或将选择推迟到晚期世代进行。遗传变异幅度较大的性状有皮壳率、单株粒数、小区产量、单株粒重等。由于性状的遗传改良效果主要由该性状的遗传率和变异幅度及选择强度所决定,因此,在选择率确定为5%情况下,遗传改良效果较好的性状为单株粒数和单株粒重。 Abstract:The genetic analysis of main agronomic characters was conducted with 10 varieties of oil sunflower(Helianthus annuus L.).The results showed that direct selection can be carried out at early generation for characters with higher heritability such as plant height,grain number pere plant,100-grain weight,diameter of disc and grain weight per plant.For maturity and percentage of shell with lower heritability,indirect selection correlated with other characters or late generation selection can be utilized.The characters showing wide genetic variation were those as percentage of shell,grain number per plant,grain yield per plot and grain weight.Since the successful improvement of a character mainly depends on its heritability,variation of heritability and intensity of selection,we suggest that the characters which may give better genetic improvement are grain number and grain weight per plant under condition of 5% selection pressure.     

猫叫综合征一家系高分辨染色体分析

本文采用高分辨染色体技术,对一例猫叫综合征患儿及其家系进行了分析,结 果提示,猫叫综合征染色体关键片段位于5p15.3→5pter。