嗜线虫致病杆菌产生抗生素的培养基及条件

本对嗜线虫致病杆菌（Xenorhadbus nematophilus）产生抗生素的发酵培养基和发酵条件进行了研究,同时对该菌代谢过程pH值、还原糖、总糖、氨基氮与抗生素产量的关系进行了分析,通过筛选该菌对碳源和氮源的要求,用正交试验初步确定了该菌产素的最佳发酵培养基和条件为：玉米粉1％,大豆粉3％,蔗糖1％,蛋白胨1.5％,KH2PO40.02％,MgSO40.2％,活化剂T0.1％;发酵培养基的起始pH值在6.0－8.0,种龄16h,接种量4％,500mL摇瓶装量15－150mL的条件下培养72h可获得较高的抗生素产量;产素量与菌代谢过程中pH、还原糖、总糖和氨基氮的变化有一定关系,通过培养基和培养条件的研究使该菌的产抗生素能力提高了56.3％。     

产灵芝胞外多糖培养基的优化及发酵指标变化

经单因素和正交试验优化,灵芝胞外多糖最佳发酵培养基各成分质量分数为:麦芽糖2%,黄豆粉1%,FeSO4·7H2O0.02%,KH2PO40.1%,土豆汁体积分数30%,pH自然,产量可达到86.36g·L-1(湿重)。灵芝胞外多糖产量受发酵过程各因素的影响,发酵过程中pH、总糖、还原糖和氨基氮有一定的相关性。灵芝多糖整个发酵过程需要144h左右,第6d达到发酵终点。     

嗜线虫致病杆菌产生抗生素的培养基及条件*

本文对嗜线虫致病杆菌 (Xenorhabdus nematophilus)产生抗生素的发酵培养基和发酵条件进行了研究 ,同时对该菌代谢过程 p H值、还原糖、总糖、氨基氮与抗生素产量的关系进行了分析。通过筛选该菌对碳源和氮源的要求 ,用正交试验初步确定了该菌产素的最佳发酵培养基和条件为 :玉米粉 1% ,大豆粉 3% ,蔗糖 1% ,蛋白胨 1.5% ,KH₂ PO₄ 0 .0 2 % ,Mg SO₄ 0 .2 % ,活化剂     

武香一号香菇液体发酵工艺优化

目的:在原有培养基基础上,进一步优化碳源和氮源配方,确定最佳浓度、合适的碳氮比.方法:采用正交试验方法对发酵培养基进行优化.结果:武香一号香菇液体摇瓶发酵最佳培养基配方为马铃薯15%、麦芽糖1.5%、酵母浸粉0.7%、麸皮3%、KH2P04 0.3%、MgSO4·7H2O0.2%、琼脂0.2%;并研究了香菇液体菌种培养过程中菌丝球数量及形态、摇瓶总重、pH值、多糖含量等指标的变化情况,绘制该菌发酵产糖的过程曲线,确定最佳发酵时间为11d.结论:菌丝生物量与摇瓶质量变化随发酵时间变化规律的一致性.摇瓶质量变化可以作为发酵终点判定的一个指标,简单易行,且不易染菌.     

金针菇意杨菌糠有机肥发酵的初步研究

通过筛选发酵配方和接种量,测定发芽指数(GI)、水分、pH、酶活性的变化,对金针菇意杨菌糠有机肥发酵进行初步研究。筛选得最佳发酵培养基配方(菌糠70%、米糠15%、麦麸15%),GI为94%。接种量为2%时,GI为92%,脲酶活性最大,为17 U,比接种量为10%(12U)和14%(13 U)高,而纤维素酶活性大小受接种量的影响较小。发酵过程中培养基的水分含量呈下降趋势,pH则呈上升趋势。脲酶最大活性为21 U,出现在第6天,在第8天降到最低值,仅为8 U。而纤维素酶活性最高值在第8天,为10 U,随之下降至8 U。这些研究结果将为金针菇意杨菌糠的肥料化研究提供一定的参考依据。     

蝙蝠蛾拟青霉菌丝体发酵的研究

用20t发酵罐培养蝙蝠蛾拟青霉。菌粉收率达2．5％,D-甘露醇含量大于8％,腺苷含量大于0．2％．对发酵过程中pH、总糖、还原糖、得率、折光等的变化规律进行了考察．确定以发酵液pH的升高和还原糖含量作为综合判断发酵终点的依据．     

蛹虫草固体发酵大豆基质的成分及抗氧化活性变化研究

以大豆为培养基质,对蛹虫草固体发酵过程中的pH值、淀粉酶、蛋白酶、总糖、还原糖、总酚、ABTS自由基清除率和FRAP进行测定,分析各种物质含量及抗氧化活性变化。结果表明,发酵过程中pH值、淀粉酶和蛋白酶先增加后减少,还原糖含量随着发酵时间延长不断下降,可溶性总糖先减少后增加。总酚含量、ABTS自由基清除率和FRAP值随着发酵时间延长先减少后增加,22d达最大值。发酵成品有望开发成为食品基料及抗氧化食品。     

金针菇在淀粉工业废水中发酵的生理生化特性

以经液化处理的淀粉工业废水作金针菇液体深层发酵的培养基,研究发酵过程中菌球形态、生物量、pH总糖、还原糖、氨态氮、糖化酶、蛋白酶的变化规律,描述了菌体的生长曲线,得到了菌丝体生长的动力学模型。第1～2d为延滞期,第3～8d为快速生长期,第8d后为衰老期。其中第3～6d菌丝体生长最为迅速,酶活力最高,基质消耗最快。发酵过程中pH呈上升趋势。对生理生化各因子之间的相互关系作了讨论。     

酯肽类抗生素547~#发酵的研究

本文报道抗生素547发酵的研究,由单一碳源、氮源、无机盐、微量元素发酵的实验结果,找出了产素较高的发酵培养基。从对种龄、接种量、装量、温度、周期等发酵条件的研究,确定了最适发酵条件.绘制了抗生素547菌株的生长代谢曲线。并用统计学方法分析了周期、pH、菌丝量、DNA、总糖、还原糖、氨基氮与抗生素产量之间的相关性,发现pH、DNA与抗生素产量之间有线性相关。     

玉米粉在赤芝液体培养中的应用研究

以菌丝含量为主要指标,研究了6种营养物质对赤芝深层培养的影响,试验结果表明,赤芝500ml小规模发酵最适培养基配方为:玉米粉4.0%,糖蜜1.5%,黄豆粉2.0%,酵母膏0.2%,KH2PO40.2%,MgSO4.7H2O 0.15%,pH 6.0。接种量为10%时在150r/min摇床上26℃振荡培养5d,菌丝含量最高,为25.1g/L;玉米粉是赤芝生长的主要因素,糖蜜是次要因素,玉米粉可以作为赤芝发酵培养基的主要原料。     

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.     

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.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细