产3-脱氧葡糖醛酮代谢酶微生物的研究*

从海洋细菌中筛选到一株产３－脱氧葡糖醛酮代谢酶活力较高的菌株Ｆｓ－４—Ｃ－３,并对其进行了最适产酶条件的研究。实验证明：以鱼肉蛋白胨为氮源、蔗糖为碳源,在培养基起始ｐＨ值为７．８～８．０,温度为２８℃,盐度为５％的情况下,培养９６ｈ,产酶最高。３－ＤＧ可以诱导产酶。     

产3—脱氧葡糖醛酮代谢酶微生物的研究

从海洋细菌中筛选到一株产３－脱氧葡糖醛酮代谢酶活力较高的菌株Ｆｓ－４－Ｃ－３,并对其进行了最适产酶条件的研究。实验证明：以鱼肉蛋白胨为氮源、蔗糖为碳源,在培养基起始ｐＨ值为７．８～８．０,温度为２８℃,盐度为５％的情况下,培养９６ｈ,产酶最高,３－ＤＧ可以诱导产酶。     

链霉菌Z94-2碱性脂肪酶产生条件及酶学性质

在１５２ 株脂肪酶产生菌中,链霉菌Ｚ９４２ 产脂肪酶活力为５９６ｕ／ ｍＬ,其最适培养基（ｇ／Ｌ） 为：糊精１０ 、黄豆饼粉３０ 、尿素１０ 、Ｋ２ＨＰＯ４ ０－５ 、ＭｇＳＯ４ ０－５ 、ＮａＣｌ １ 和ＡＥＯ９ ０ ．５ ,产酶的最适条件为：初始ｐＨ９ ．５ ～１０－０ ,在２６ ℃培养４８ｈ 。用ＰＶＡ 橄榄油乳化系统测定该酶的最适ｐＨ９ ．８ ,最适温度３７ ℃,在ｐＨ８－６ ～１０－２ 于５ ℃存放２４ ｈ ,酶活力不变。０－１４ｍｏｌ／Ｌ 的氯化钙有较大的激活作用。     

链霉菌Z94-2碱性脂肪酶产生条件及酶学性质

在１５２株脂肪酶产生菌中,链霉菌Ｚ９４－２产脂肪酶活力为５９６ｕ／ｍＬ,其最适培养基（ｇ／Ｌ）为：糊精１０、黄豆饼粉３０、尿素１０、Ｋ２ＨＰＯ４０．５、ＭｇＳＯ４０．５、ＮａＣｌ１和ＡＥＯ９０．５,产酶的最适条件为：初始ｐＨ９．５～１０．０,在２６℃培养４８ｈ。用ＰＶＡ橄榄油乳化系统测定该酶的最适ｐＨ９．８,最适温度３７℃,在ｐＨ８．６～１０．２于５℃存放２４ｈ,酶活力不变。０．１４ｍｏｌ／Ｌ的氯     

放线菌果胶酶产酶条件及酶促反应条件的研究

从埋麻土壤中分离到放线菌２９８株,经初筛和复筛得到产酶活性较高的一株放线菌５－７１。最适产酶条件是：果胶０．５％,葡萄糖０．５％,蛋白胨０．５％,酵母粉０．１％,Ｋ２ＨＰＯ４ ０．１％,ＫＨ２ＰＯ４ ０．１％,ＮａＣｌ０．１％,ＭｇＳＯ４·７Ｈ２Ｏ０．０５％,ｐＨ８．０。２５℃培养３天达产酶高峰。通气量对产酶影响不大。酶促反应最适条件是：ｐＨ９．６,４５℃,底物果胶浓度０．７５％,作用时间９０ｍｉ     

芽孢杆菌E2菌株纤维素酶性质的研究

芽孢杆菌Ｅ２菌在５５℃下生长良好,在培养液中能大量积累胞外纤维素酶（１９０ｍｕ／ｍＬ培养液）,所产生的纤维素普单一的羧甲基纤维素酶（ＣＭＣａｓｅ）。羧甲基纤维素钠（ＣＭＣＮａ）为其专一性底物。该酶作用的ｐＨ为４．５－８．０;最适ｐＨ为６．５－７．０;在ｐＨ４．０－８．０范围内较稳定,酶作用的最适温度为５５℃;在６０℃处理１０,３０,６０,９０以及１２０分钟后,残余酶活分别为９５％,８０．３％,４０     

产纤维素酶菌株宇佐美曲霉Y-11产酶条件及酶性质的研究

通过正交试验,对宇佐美曲霉纤维素酶固态发酵条件进行了研究,其较适培养基为：麸皮与稻草配比为２：３,氮源：尿素,含水量：２００％（液固比）,ｐＨ：５．５。２８－３０℃培养７２小时,ＣＭＣ酶活力为５．０５（ｕ／ｍｌ）,滤纸酶活力达到１．０４（ｕ／ｍｌ）。ＣＭＣ酶及滤纸酶最适ｐＨ分别为４．４１、６．０６;最适温度分别为６５℃、５５℃。酶的热稳定性与ｐＨ稳定性较高。     

纤维素酶酶解稻壳的条件试验

本文报道康氏木霉Ｎ_２－７８（Ｔｒｉｃｈｏｄｅｒｍａｋｏｎｉｎｇｉ）纤维素酶产生和酶解稻壳的适宜条件。实验结果表明,在稻草粉麸皮固体培养基上,纤维素酶产生的适宜条件为稻草粉和麸皮的比例为７：３,培养基含水量为２５０％,ｐＨ为６．０—６．５,温度为３０℃,时间为３ｄ。酶解稻壳的最适条件为：ｐＨ为４．４,温度为４０℃,作用时间为３ｄ,酶曲量和底物量比例为１：３。     

1，6－二磷酸果糖产生菌的筛选及最佳培养条件的研究

１,６－二磷酸果糖（ＦＤＰ）广泛应用于治疗心血管疾病．本文进行了１,６－二磷酸果糖产生菌的筛选和最佳条件的研究。筛选出菌株ＨＹ２具有较高的产１,６－二磷酸果糖酶活力,高达１６０ｍｇＦＤＰ／ｇｗｅｔｃｅｌｌｓ,菌体生长的最适培养条件为：麦芽汁培养基糖度为１２柏林,培养温度为２８℃,ｐＨ６．０～６．５,菌体收率达７．０％左右。     

无花果蛋白酶在阴离子交换树脂上的固定化

无花果蛋白酶通过８％戊二醛活化载体,共价结合到聚苯乙烯阴离子交换树脂ＧＭ２０１上,固定化作用在ｐＨ７．７,酶浓度０．８ｍｇ／ｇ树脂,４℃下进行６ｈ。得到的固定化酶表观Ｋ_ｍ值（酪蛋白,１．１１×１０~（－４）ｍｏｌ／Ｌ）小于溶液酶Ｋ_ｍ值（１．９６×１０~（－４）ｍｏｌ／Ｌ）;固定化酶活性在ｐＨ６～８保持稳定,溶液酶最适ｐＨ为７．２;固定化酶最适温度由溶液酶的５０～６０℃移至３７℃;固定化酶２５℃保持７ｄ,重复水解酪蛋白７次后,保留８３．３％活性。固定化酶对酪蛋白水解度达４７．５％,对大豆球蛋白达１１．６％。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

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     

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.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.