木糖异构酶序列结构特点、耐热机理及分子改造研究进展

近年来,随着发展低碳经济的迫切需要,可再生资源利用研究方兴未艾,其中,构建充分利用木质纤维素水解产物木糖生产乙醇的重组菌成为研究热点.木糖异构酶由于不需要辅酶,成为构建利用木糖重组酵母的首选途径.文中对近年来木糖异构酶的研究进展进行了综述.首先介绍了木糖异构酶的基本性质、序列、结构和功能特性,然后对其耐热机理进行了总结归纳;重点阐述了基于序列及结构进行的酶分子改造研究,包括底物特异性改造、热稳定性改造等;同时,结合作者的研究经历,对如何提高嗜热木糖异构酶在常温下的活性进行了探讨.最后,对木糖异构酶的研究进展进行了总结和展望,对基于结构改善木糖异构酶催化活性及构建新型高效利用木糖生产乙醇的重组菌具有重要的指导意义.     

Genetic characteristics of 2009 pandemic H1N1 influenza a viruses isolated from Mainland China

A total of 100 HIN1 flu real-time-PCR positive throat swabs collected from fever patients in Zhejiang,Hubei and Guangdong between June and November 2009,were provided by local CDC laboratories.After MDCK cell culture,57 Influenza A Pandemic (H1N1) viruses were isolated and submitted for whole genome sequencing.A total of 39 HA sequences,52 NA sequences,36 PB2 sequences,31 PB1 sequences,40 PA sequences,48 NP sequences,51 MP sequences and 36 NS sequences were obtained,including 20 whole genome sequences.Sequence comparison revealed they shared a high degree of homology (96％～99％) with known epidemic strains (A/Califomia/04/2009(H1N1).Phylogenetic analysis showed that although the sequences were highly conserved,they clustered into a small number of groups with only a few distinct strains.Site analysis revealed three substitutions at loop 220 (221-228) of the HA receptor binding site in the 39 HA sequences:A/Hubei/86/2009 PKVRDQEG→PKVRDQEA,A/Zhejiang/08/2009 PKVRDQEG→PKVRDQER,A/Hubei/75/2009PKVRDQEG→PKVRDQGG,the A/Hubei/75/2009 was isolated from an acute case,while the other two were from patients with mild symptoms.Other key sites such as 119,274,292 and 294 amino acids of NA protein,627 of PB2 protein were conserved.Meanwhile,all the M2 protein sequences possessed the Ser32Asn mutation,suggesting that these viruses were resistant to adamantanes.Comparison of these sequences with other H1N1 viruses collected from the NCBI database provides insight into H1N1 transmission and circulation patterns.     

大黄鱼池塘不同混养模式生态学特征比较

利用菊花江蓠、双齿围沙蚕和大黄鱼在陆基围隔中构建鱼+藻(FG)、鱼+藻+沙蚕(FGP)以及鱼+沙蚕(FP)3种复合养殖模式,以单养鱼(F)模式为对照,探讨不同模式系统的沉积物、水体环境状况、养殖效益及氮、磷元素的回收效率.结果表明:菊花江蓠主要作用于系统水体中氮和磷的净化,具藻处理中氮、磷含量均显著低于无藻处理,对于水体环境中磷的利用效率达到投入量的33.8%～34.0%;沙蚕作用主要体现在对沉积物环境的改善,具沙蚕处理中氮、磷含量低于不具沙蚕处理,且在沉积物表层(1～2 cm)和次表层(2～4 cm)差异均显著.相对于F处理,FGP及FP处理总氮(TN)、总磷(TP)和无机磷(IP)分别下降了8.9%～9.2%、6.1%～6.3%和8.0%～8.1%.沙蚕对于沉积物中磷的回收达到投入量的7.5%～7.8%,有效减缓了磷在沉积物中的积累.FGP系统具有最佳的物质利用率及资源效益.     

遗传学与基因组学整合课程探讨

基因组学是遗传学的重要学科分支,具有全新研究思维和技术手段,已经形成一个系统而完整的体系。在本科课程中加强基因组学教学是遗传学学科发展的要求,有利于对学生进行科学思维训练、提高学生生物伦理学修养和学习兴趣。整合遗传学与基因组学课程符合学科发展规律和教学规律。目前国内已经基本具备相关教材,通过调整遗传学教学内容,合理选择教学方法,充分利用计算机辅助教学,在本科教学中整合遗传学与基因组学是可行的。     

Large odorous frogs (<Emphasis Type="Italic">Odorrana graminea</Emphasis>) produce ultrasonic calls

We present the first data on the vocalizations of large odorous frogs (Odorrana graminea, previously Odorrana livida), from southern China. The males produce diverse broadband signals most of which contain ultrasonic harmonics. Six basic call-types were identified based on the number of call notes, fundamental frequency, call/note duration, frequency modulation patterns and spectral composition. O. graminea is one of only a few non-mammalian vertebrates able to detect ultrasound, but its tympanic membranes are not recessed. These results should stimulate further studies to provide new insights into the mechanisms underlying high-frequency communication in anurans.     

Promotion of Monacolin K Production by <Emphasis Type="Italic">Agrobacterium tumefaciens</Emphasis>-Mediated Transformation in <Emphasis Type="Italic">Monascus albidus</Emphasis> 9901

The binary vector pCAMBIA3300-gpdA-hph-trpC with hygromycin B phosphotransferase (hph) was constructed and transformed into Monascus albidus 9901 by Agrobacterium tumefaciens-mediated transformation, with gene hph as the selective marker. In order to improve the efficiency of A. tumefaciens-mediated transformation in M. albidus 9901, we optimized various factors including concentration of M. albidus 9901 spores, cell density of A. tumefaciens, co-cultivation time, temperature, and acetosyringone concentration. Most transformants of M. albidus 9901 could grow stably on media containing 50 μg ml⁻¹ hygromycin B up to five generations. The presence of hph was identified by PCR. Two transformants H1 and H2 which produced more Monacolin K than M. albidus 9901 were screened, and the concentration of Monacolin K in the fermented millet by H1 and H2 increased by 42.15% and 40.34% respectively compared with that produced by M. albidus 9901.     

Molecular identification of endophytic fungi from medicinal plant <Emphasis Type="Italic">Huperzia serrata</Emphasis> based on rDNA ITS analysis

Fifty-two endophytic fungi strains with different colony morphologies were isolated from stems, leaves and roots of Huperzia serrata (Thunb. ex Murray) Trevis. collected from Bawangling Reserve of Hainan Province in southern China. They were identified mainly based on rDNA ITS sequences and phylogenetic analysis. The results showed that all strains belonged to four classes, i.e. Sordariomycetes (92.31%), Dothideomycetes (3.85%), Pezizomycetes (1.92%) and Agaricomycetes (1.92%). Forty-seven strains were identified at the genus level, including Glomerella (Colletotrichum), Hypocrea (Trichoderma), Pleurostoma, Chaetomium, Coniochaeta (Lecythophora), Daldinia, Xylaria, Hypoxylon, Nodulisporium, Cazia and Phellinus. As to the other five strains, three were identified at the order level and two at the family level, indicating that a great diversity of fungi taxa exists in H. serrata. Most isolated strains belonged to the genus of Glomerella (Colletotrichum) and Hypoxylon, twenty-one from Glomerella and its anamorph Colletotrichum (42.3% of total isolated strains) and ten from Hypoxylon (19.2% of total isolated strains). Pleurostoma, Chaetomium, Coniochaeta (Lecythophora), Daldinia, Xylaria, Hypoxylon, Nodulisporium, Cazia and Phellinus were reported as endophytic fungi isolated from H. serrata for the first time.     

Styles of verbal expression of emotional and physical experiences: A study of depressed patients and normal controls in China

Sixty depressed patients and 52 normal controls completed three selfreport inventories: the Symptom Checklist-90 (SCL-90), the Beck Depression Inventory (BDI) and a new Verbal Style Investigation Schedule (VESIS) developed by the first author. The VESIS uses 16 key emotional and physical terms from Western inventories and identified the words and phrases most commonly used by Chinese patients to express these feeling states. Chinese subjects commonly used the key term itself for only 3 or the 16 key terms; they usually preferred to use other words or phrases to express the feeling state. We categorized these Chinese expressions into four styles of verbal expression: Psychological, Somatic, Neutral (i.e., a mixture of psychological and somatic) and Deficient (i.e., lack of expression because of denial or suppression). Three of the 12 key emotional terms of the VESIS (depressed, fearful, and anxiousness) were more commonly expressed in a somatic or neutral mode than the other key emotional terms. The key terms suicidal interest and being punished were more commonly expressed in a deficient style than other key emotional terms. The somatic factor score of the SCL-90 was not correlated with increased somatic expression of emotional states; thus patients who have multiple somatic complaints are not more likely to express emotions somatically. The hypothesis of somatization is discussed in light of this study.     

A new family of polyoxometalate compounds built up of Preyssler anions and trivalent lanthanide cations

Four new polyoxometalate compounds built on Preyssler anions and trivalent lanthanide cations, Na₂[{Ce(H₂O)₈}₄{Na(H₂O)P₅W₃₀O₁₁₀}] · 12H₂O (1), H₄Na₄[Nd₂(H₂O)₁₄{Na(H₂O)P₅W₃₀O₁₁₀}] · 22H₂O (2), K₂Na[Eu₃(H₂O)₁₄(HNA)₃{Eu(H₂O)P₅W₃₀O₁₁₀}] · 3H₂O (3 NA = nicotinic acid) and H₂[Ce₄(H₂O)₁₆(HNA)₆{Na(H₂O)P₅W₃₀O₁₁₀}] · 12H₂O (4) have been synthesized and characterized by elemental analysis, IR, TG and single crystal X-ray diffraction. Compound 1 exhibits a tetrasupporting polyoxometalate cluster structure where four {Ce(H₂O)₈}³⁺ fragments are supported on the [Na(H₂O)P₅W₃₀O₁₁₀]¹⁴⁻ cluster. Compound 2 shows a one-dimensional chain structure built from [Na(H₂O)P₅W₃₀O₁₁₀]¹⁴⁻ clusters linked by Nd³⁺ cations. Compound 3 displays a one-dimensional chain structure constructed of [Eu(H₂O)P₅W₃₀O₁₁₀]¹²⁻ clusters bridged by Eu³⁺ cations. Compound 4 has a 2D network formed by 1D chains and {Ce₂(H₂O)₆(HNA)₆}⁶⁺ linkers. Compounds 2-4 represent the first extended structures based on Preyssler anions. In addition, the fluorescent activity of compound 3 is reported.     

江苏某地健康绵羊群产志贺毒素大肠杆菌体内分离株的分子流行病学及致病力

【目的】探讨江苏某羊场健康绵羊体内产志贺毒素大肠杆菌的带菌和流行情况,同时就分离株的致病力和对Vero细胞的毒性作用作了研究。【方法】基于本实验室已经建立的EHEC O157:H7 EDL933W株的stx1、stx2、eaeA、hlyA四个基因的多重PCR检测并配合选择性增菌、平板筛选等方法对STEC进行分离鉴定。【结果】在为期6个月的连续跟踪调查中,共分离到STEC菌株107株,分离率为19.4%(107/550)。分离株属于41种O血清型、62种O:H血清型,未定型(ONT)有22株,粗糙型(OR)1株。其中属于绵羊STEC的优势血清型有O5(2株)、O91(1株)、O103(1株)。本文检测到的优势血清型为O93,stx2阳性菌株的分离率较stx1阳性菌株的分离率高,LD50测定结果表明分离株对小鼠致病力不高,受试的3个分离株均不能致小鼠死亡。对107株stx阳性分离株噬菌斑试验表明,71株阳性菌株携带噬菌体(66.3%,71/109)。受试分离株进行Vero细胞毒性试验,其中有一个菌株stx基因阳性但不能使Vero细胞产生病变。【结论】绵羊是STEC的天然宿主,可健康带菌。虽然STEC分离株对小鼠的致病力较弱,但不能排除其对人类安全的威胁。STEC携带志贺毒素基因并不意味着一定表达志贺毒素,需对志贺毒素的表达及调控机理做进一步的研究。