紫外线诱变选育聚丁二酸丁二醇酯（PBS）高降解活性菌株

以PBS降解菌HJ03（Alternariasp．）为出发菌株,通过紫外诱变,透明圈初筛及PBS薄膜复筛,获得一株降解能力增强且对温度和pH耐受力均得到提高的突变株HJ10。与出发菌株相比,HJ10在培养初期气生菌丝少,而培养7d时菌落致密且生长速度较快。经过连续继代培养7代后发现,突变株的降解活力保持了良好的遗传稳定性,其降解率较出发菌株提高百分比达14．4％以上;在最适降解温度范围内（25℃～30℃）和不适宜降解的温度条件下突变菌株Ⅻ10的降解率均高于出发菌株;各pH条件下,突变株对PBS的降解能力明显优于出发菌株,尤其在pH5．0时降解率提高了22．80％。     

激光诱变玫瑰孢链霉菌结合链霉素抗性筛选法选育达托霉素高产菌株

将经过20 mW激光辐照20 min的达托霉素(Daptomycin)生产菌株-玫瑰孢链霉菌(Streptomyces roseosporus)D-38的孢子悬液倾注在含有1．9λg／mL链霉素的高氏一号培养平板上。通过链霉素抗性法筛选获得了10％正变率的突变株,其中突变株LC-54摇瓶发酵单位为81．2 mg／L,比出发菌株提高了39％。     

南昌霉素高产菌株的链霉素抗性基因突变诱变筛选研究

通过对链霉素对南昌霉素（Nanchangmycin)产生菌NS－41－80菌株孢子的致死浓度测定基础上,采用诱变剂甲基磺酸乙酯（EMS）的不同诱发剂量对菌株孢子进行诱变处理,诱变处理的孢子涂布在含链霉素（10ug/mL)致死浓度的高氏平板上,获得了大量的链霉素抗性基因（str)突变株。然后从3,000株链霉素抗性基因（str)突变株中通过初筛获得比诱变出发菌株产素能力提高20％以上的菌株202株,再进一步通过摇瓶复筛,获得比出发菌株产素能力分别提高100％,200％,300％高产菌株为48株,7株和1株,分别为复筛菌和初筛菌株的23．76％和1．60％,3．46％和0．23％,0．5％和0．03％,将产素能力提高240％以上5个菌株连同出发菌株连续3批次进行摇瓶发酵结果,5个突变株的产素能力均比出发菌株的产素能力提高57％－96．4％,其中突变株80－5．3－165菌株摇瓶发酵单位达6,000ug/mL以上,3批次摇瓶平均发酵单位达5,855ug/mL,建立了南昌霉素高产菌株的链霉素抗性基因突变诱变快速高效的筛选方法。     

降氰菌突变株处理合成氨企业含氰废水的研究

从合成氨废水污染的土壤和排水沟底泥中经过多次富集、分离,筛选出了具有较高耐氰和降氰能力的野生型菌株,经过紫外诱变得到2株具有高效降氰能力的突变株HN-1和HN-4。利用接触氧化法进行合成氨企业含氰废水的降氰处理时加入突变株HN-1和HN-4,处理效果大大增强,在水力停留时间(HRT)2 h的情况下,氰的降解率可达90%以上。     

金霉素链霉菌的诱变育种

从金霉素链霉菌(Streptomyces aureofaciens)重组体2U一84经紫外线处理得到A3-32突变株,产量比2U一84提高10．6％以上。A3—32突变株又经紫外线处理,得到一株分泌金黄色色素的突变株5一43,产量为A3-32的60—70％。而5一43突变株经不同诱变因素：紫外线、乙烯亚胺及氮芥处理,均得到色素形成能力消失的突变株,这些菌株的产量均比5—43高,提高的幅度也较大。其中紫外线处理得到的u一42突变株比5—43突变株提高78％,比重组体2u 8{提高21．5％。色素形成能力愈小者,其产量愈高,这说明产量与色素之间存在着一定的相关性。由弱孢子型6—15突变株经乙烯亚胺与紫外线复合处理,得到孢子丰富,产量明显提高的EU-63突变株,比重组体2U一84提高49．6％。     

发酵生产十六烷二羧酸的研究

以热带假丝酵母(Candida tropicalis)T_25-14为出发菌株,经紫外线多次诱变,获得生产十六烷二羧酸(DC₁₆)能力比原株提高25％以上的4株突变株。其中UH-3-9突变株经多次复筛,产DC16能力都比T25-14,菌株提高50％以上。经摇瓶条件试验,不加其他生长碳源。只加15％(v／v)正十六烷(nCl6),发酵96h,DC16为48．2g/L,转化率41％,产品纯度95．9％。     

以抗结构类似物筛选高产L—赖氨酸酵母突变株

以啤酒酵母（Saccharomycescerevisiae)I菌株为出发菌株,经紫外线处理后,在含2.0mg/L的5-（2-氨基乙基）－L一半胱氨酸（AEC）的平板上获得18株生长良好的抗性突变林,编号为I－1～18,其中Ⅰ-Ⅱ株抗AEC达10～15mg／L,是出发株抗性最高浓度的10倍左右,并且Ⅰ—11株的L-赖氨酸含量（重量与重量比,100％）较出发株提高3.89％。以Ⅰ－11株作亚硝酸诱变处理,在含30～120mg／LAEC的培养基上又获得18株抗性突变株,其中Ⅰ11－L和Ⅰ11－MAEC的耐受浓度可达1300mg/L,其赖氨酸的含量较Ⅰ菌株的提高了27．42％和40．28％。     

抗性突变株筛选法选育碱性脂肪酶高产菌

以扩展青霉（Penicillum expansum)P1336为出发菌株,研究研究琥珀酸和制霉菌素对菌株生长的影响。经过多代诱,获得一突变株W－2580,其中酶水平比出发株P1336菌株提高34．7％,该菌菌丝体表角固醇下降了12．2％。     

枯草芽孢杆菌B-903菌株的诱变选育

枯草芽孢杆菌B-903菌株是由河南省农业科学院植物保护研究所从郑州果园中分离得到,其代谢产生的抗菌物质对多种植物病原真菌具有较强抑制作用。以此菌株为出发菌株,进行亚硝基胍（NTG）和微波诱变处理,确定了,二者诱变处理的最佳处理剂量：NTG最佳处理浓度为200μg／mL,微波诱变为HI微波挡（850W、脉冲频率2450MHz）处理100s,筛选出13个高效突变株。经传代实验,2株高效突变株N1和W2抑菌圈直径分别稳定在26mm和24mm以上,比出发菌株提高21．8％和14．8％．     

1株聚乳酸降解细菌的筛选、鉴定及产酶研究

从污泥中筛选出1株对聚乳酸（poly—L—lacticacid,PLA）具有降解活力的细菌DSL09,该菌株对PLA的乳化液、粉末及薄膜都具有降解作用。通过形态学、16SrDNA比对及生理生化特性的分析,鉴定该菌株属于芽胞杆菌属（Bacillus sp．）。为提高该菌株对PLA的降解活力,对其进行了紫外诱变,获得了稳定遗传的突变株DSL09-60b,该突变株的PLA降解活性提高至原始菌株的1．5倍。对该突变株产PLA降解酶的发酵条件进行了优化,经测定DSL09-60b在初始培养基pH为8．0、0．5％酪蛋白为诱导物、接种量6％（体积比）的条件下37℃培养54h时发酵液酶活性最高。     

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     

Similar aerosol emission rates and viral loads in upper respiratory tracts for COVID-19 patients with Delta and Omicron variant infection

Highlights
1 Aerosol emission rates of Delta or Omicron patients were similar.
2 Viral loads in upper respiratory tract of Alpha, Delta and Omicron patients were similar.
3 Viral loads in upper respiratory tract of vaccinated or unvaccinated Delta patients had no difference.     

Recombinant human interferon-α1b inhibits SARS-CoV-2 better than interferon-α2b in vitro

Highlights
1) A comprehensive evaluation method for anti-SARS-CoV-2 drugs was established based on RT-qPCR, TCID₅₀ method, and immunofluorescence.
2) A significant antiviral effect of rHuIFN-α1b was shown with EC₅₀=0.12 IU/mL in Vero cells and EC₅₀=0.52 IU/mL in Calu-3 cells, which was better than rHuIFN-α2b (EC₅₀=0.25 IU/mL in Vero cells and EC₅₀=2.48 IU/mL in Calu-3 cells).
3) rHuIFN-α1b has a good potential in the application of anti-COVID-19 therapy.     

Continued antigenic variation of highly pathogenic avian influenza A (H7N9) virus in laying hens in China, 2020–2021

Highlights
1. 13 strains of H7N9 viruses from laying hens in 2020 and 2021 were identified.
2. H7N9 viruses in China comprised at least 11 genotypes.
3. H7N9 viruses are high pathogenic in chickens, not in ducks.
4. The most H7N9 viruses cross-reacted poorly with H7-Re3 antiserum.
5. The H7-Re3 vaccine was unable to prevent H7N9 infection.