新型肌苷新生菌——产氨短杆菌GMBA—800选育和特性的初步研究

采用多种方法诱变获得一株新型肌苷产生菌－－产氨短杆菌ＧＭＢＡ－８００,对其生长和发酵条件进行初步研究。肌苷产量从５ｇ／Ｌ提高到１８．４１ｇ／Ｌ,发酵周期从８４ｈ缩短为６３ｈ。菌株遗传性状稳定。     

原生质体融合选育肌苷产生菌产氨短杆菌GMA—2802

以肌苷产生菌产氨短杆菌ＧＭＡ－２７２２（Ａｄｅ－、 Ｇｕａ－、ＶＢ１－、Ｒｉｆｒ）和 ＧＭＡ－２７７６（Ａｄｅ－、 Ｂｉｏｔｉｎ－、ＶＢ１－、Ｓｍｒ）为出发菌株,经原生质体融合,将目的标志加以组合,获得遗传性状稳定、摇瓶发酵６１ｈ,产肌苷２５．４ｇ／Ｌ的融合子 ＧＭＡ－２８０２（Ａｄｅ－、Ｇｕａ－、Ｂｉｏｔｉｎ－、ＶＢ１－、 Ｒｉｆｒ、Ｓｍｒ）。     

肌苷产生菌缺失核苷水解酶活性突变株选育及其发酵生产试验

以枯草芽孢杆菌ＪＳＩＭ－１０１９为出发菌株,经物理、化学诱变剂连续处理,获得一株缺失核苷水解酶活性的突变株ＪＳＩＭ－Ｂ－１９８。该突变株不能降解肌苷,应用于发酵生产中,肌苷产量显著增加。在２００００升发酵罐中,连续１０罐批,平均产肌苷８．３８ｇ／Ｌ,对糖转化率２１．９８％,发酵周期５０ｈ￣６０ｈ,该菌株遗传性能稳定,已在工业生产中应用。     

重组人生长激素在大肠杆菌BL21（DE3）中高效表达研究

对重组人生长激素基因工程菌ｐＥＴ－１１ｂ／ｒｈＧＨ／ＢＬ２１的培养条件进行了优化,在ＮＢＳ ＭＰＰ－４０发酵罐中实现了高密度培养和高效表达,三批实验结果表明,在较短的发酵时间（１２ｈ）内细菌干重达８５ｇ／Ｌ,重组人生长激素占总蛋白量的２５％左右。     

温度适应范围大的谷氨酸生产菌GMH—908选育,发酵及应用效果

以谷氨酸生产菌天津短杆菌（Ｂｒｅｖｉｂａｃｔｅｒｉｕｍｔｉｅｎｔｓｉｎｅｎｓ）Ｔ６－１３为出发菌株,经菌体或原生质体紫外线（ＵＶ）、氯化锂、香豆素等多因子诱变和高温驯化,选育出琥珀酸、生物素营养缺陷型,耐高糖、耐高谷氨酸又不利用谷氨酸,且温度适应范围大（既可在常温３２－３８℃发酵,又可在高温３６－４２℃发酵）的突变株ＧＭＨ－９０８。以淀粉糖为碳源,生物素亚适量,摇瓶常温发酵产酸９５ｇ／Ｌ以上,高温发酵产酸７４．９ｇ／Ｌ,比出发菌株Ｔ６－１３分别提高２６．６７％和２２．９９％;工业生产常温发酵月平均产酸８５－８８ｇ／Ｌ,转化率５２－５４ｇ％,单罐最高产酸１０８ｇ／Ｌ,转化率５８％;高温发酵产酸达７６．５ｇ／Ｌ,转化率４９．５％。     

真养产碱杆菌突变株65—7产羟基丁酸与羟基戊酸共聚物的研究

研究了真养产碱杆菌突变株６５－７,以葡萄糖为主原料,添加丙酸或戊酸,采用二步发酵积累共聚物聚β－羟基丁酸－β－羟基戊酸（ＰＨＢＶ）。摇瓶总发酵时间为５０ｈ,细胞干重达７－１１ｇ／Ｌ,共聚物含量占细胞干重的７０％以上,其中β－羟基戊酸（３ＨＶ０含量占ＰＨＢＶ的１０－７２％,主要取决于不同碳源的组成,丙酸和戊酸对ＨＶ的转化率分别为０．４１－０．６３ｇＨＶ／ｇ丙酸和０．４０－０．７４ｇＨＶ／ｇ戊酸,制得     

L－赖氨酸快速发酵新菌种及工艺研究

以我室选育的赖氨酸生产菌Ｓ－２１－２４为出发菌株,经硫酸二乙酯（ＤＥＳ）和紫外线（Ｕ．Ｖ．）的复合处理,选育到一株代谢速率高,发酵周期短的新菌株ＦＴＳ－１。对该菌的发酵条件作了研究,选择了最佳培养条件,该菌在５Ｌ发酵罐中发酵４８小时产酸８０ｇ／Ｌ以上,７２小时产酸可达１１０ｇ／Ｌ。     

法夫酵母PLX—A11发酵纤维素酶水解物合成虾青素

法夫酵母（Ｐｈａｆｆｉａ ｒｈｏｄｏｚｙｍａ）ＰＬＸ－Ａ１１菌株能够发酵纤维素酶水解物进行虾青素的生物合成。纤维素的酶解物主要为纤维二糖和葡萄糖,在另外添加适量其它营养物后可被法夫酵母发酵用于生长及俣成虾青素。摇瓶试验结果表明,培养１０８ｈ,法夫酵母的生物量可达２．３ｇ／Ｌ,虾青素的产率达９１３．４μｇ／ｇ干细胞,虾青素体积产率为２．１ｍｇ／Ｌ。在２Ｌ罐的发酵试验中,法夫酵母的生物量可达３．２３ｇ     

L－赖氨酸快速发酵新菌种及工艺研究

以我室选育的赖氨酸生产菌Ｓ－２１－２４为出发菌株,经硫酸二乙酯（ＤＥＳ）和紫外线（Ｕ．Ｖ．）的复合处理,选育到一株代谢速率高,发酵周期短的新菌株ＦＴＳ－１。对该菌的发酵条件作了研究,选择了最佳培养条件,该菌在５Ｌ发酵罐中发酵４８小时产酸８０ｇ／Ｌ以上,７２小时产酸可达１１０ｇ／Ｌ。     

真养产碱杆菌二级连续培养系统中稀释率对聚β—羟基丁酸合成的影响

在研究真养产碱杆菌ＷＳＨ３一级连续培养动力学的基础上,采用二级连续培养系统对不同稀释率下聚β羟基丁酸的生产进行了研究。结果表明：在一级连续培养系统中,当稀释率为０２１ｈ－１时,细胞干重最大值达２７１ｇ／Ｌ;二级培养系统中,稀释率为０１４ｈ－１时细胞干重最大值为４７６ｇ／Ｌ;在稀释率为０１２ｈ－１时,ＰＨＢ的生产强度达到最大值为２５０ｇ／（Ｌ·ｈ）,但胞内ＰＨＢ含量仅为４７６％;在稀释率为００７５ｈ－１时,产物对基质的转化率达到最大值为０３８ｇ／ｇ,此时ＰＨＢ的生产强度达２１４ｇ／（Ｌ·ｈ）和胞内ＰＨＢ含量±７２１％;随着细胞比生长速率的增长,细胞中ＰＨＢ含量和单位菌体合成ＰＨＢ的量不断下降。     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various     

Pathogenic Characterization and Full Length Genome Sequence of a Reassortant Infectious Bursal Disease Virus Newly Isolated in Pakistan

<正>Dear Editor,Infectious bursal disease (IBD) is one of the most important diseases of the poultry. The IBD virus (IBDV), a nonenveloped virus belonging to the Birnaviridae family with a genome consisting of two segments of double-stranded RNA (segments A and B), targets B lymphocytes of bursa of Fabricious leading to immunosuppression. In Pakistan,poultry farming is the second biggest industry and IBD is the second biggest disease threating the poultry sector.However, there is limited genome information of IBDV