NTG和UV复合诱变米曲霉原生质体选育米蛋白分解菌的研究

以米曲霉（Ａ．ｏ－２）原生质体为对象，采用ＮＴＧ和ＵＶ作为诱变剂进行单因子和多因子复合诱变处理，在以米渣为主要原料的固体培养基上培养，选育出中性蛋白酶活力较高、生长快、易于培养的变异株Ｎ－４。在原料配比为米渣：麦麸＝２：１、培养时间为４８ｈ、培养温度为３０℃的培养条件下，变异株Ｎ－４的中性蛋白酶活力最高，比出发菌株Ａ．ｏ－２提高３２．６％。     

米曲霉giF-10内切葡聚糖酶基因在大肠杆菌中的表达

【目的】克隆米曲霉giF-10内切葡聚糖酶基因并检测其在大肠杆菌中的表达。【方法】以自行分离筛选出的天然米曲霉giF-10的基因组DNA为模板,PCR高保真扩增,扩增产物连接到pMD19-T克隆载体上,并构建原核表达载体,转化大肠杆菌BL21(DE3)。【结果】序列分析表明,其长度为1 251bp,编码417个氨基酸,序列比对发现与内切葡聚糖酶基因CelB序列相似性高达100%,将此基因注册GenBank(HQ739052)。刚果红水解圈筛选结果表明已成功表达。【结论】克隆了米曲霉giF-10内切葡聚糖酶基因,并在大肠杆菌成功表达,为纤维素酶工业化生产奠定基础。     

一种筛选染料脱色真菌的新方法——脱色圈法

以孟加拉红为指示染料,利用脱色透明圈法从土壤微生物中筛选得到一株脱色菌,经初步鉴定为黑曲霉（Aspergillusniger）,并对该菌株的脱色能力进行了初步检测。结果表明：该黑曲霉菌株适应能力较强,具有较强的染料脱色能力;以孟加拉红为指示染料的脱色透明圈法分离染料脱色菌的效果好,是一种简单、方便有效的方法。     

一株分离自竹黄产蒽醌类色素菌株的鉴定及其培养特性

以分离自竹黄菌天然子座的LBR-SB6菌株为出发菌株,通过对形态特征、培养特性的研究,确定了该菌株为曲霉菌属Aspergillus sp.以改良查氏培养基为基础,对LBR-SB6液态发酵碳氮源等条件作了初步探讨,结果表明:乳糖、麦芽糖和玉米浆、亚硝酸钠分别是菌株生长和产色素的最佳碳源和氮源,1.0%竹汁对菌株生物量和色素生成量具有明显的促进作用.最终确定了LBR-SB6菌株液态发酵培养的最佳条件为:乳糖2%,亚硝酸钠0.2%,玉米浆0.1%(以干物质计),1.0%竹汁,磷酸氢二钾0.1%,硫酸镁0.025%,氯化钾0.5%,硫酸亚铁0.001%;最适温度25～28℃,摇床转速150～200 r/min.起始pH值7.6～8.0.研究结果将为蒽醌类色素的生物合成以及在医药领域的研究应用提供一定的科学依据.     

解磷真菌驱动磷灰石固定重金属铅的地球化学模拟研究

结合磷灰石和解磷菌进行农业土壤铅修复是环境修复领域的新兴技术。然而仅靠实验很难全面解析修复过程中的详细反应过程和铅的成矿机制,特别是难以解释目标稳定矿物氟基磷酸铅为何不是主要产物。本文主要利用GWB软件中的React和Act2两个程序模块,基于前人实验数据设置模拟参数,对这一科学问题进行探究。首先用React程序模块的滴定模式（Titration）来研究黑曲霉复合氟基磷灰石的除铅过程,即通过向反应体系中逐步滴加草酸来模拟黑曲霉分泌草酸的过程。反应体系中Pb²⁺初始浓度为8.4 mmol·L^-1,草酸总添加量为2.0 g·L^-1,氟基磷灰石总添加量为8.3 g,其中草酸和氟基磷灰石分为100步添加到体系中。React模拟过程终止后,可得到体系pH值、主要离子浓度（Pb²⁺、Ca²⁺、H₂PO₄^-、F^-和C₂O₄^2-）以及生成产物随着草酸和氟基磷灰石添加的变化曲线。然后将黑曲霉与氟基磷灰石培养后的浸出液与Pb（NO₃）₂溶液混合后,用Act2模块模拟其草酸和F^-浓度变化对铅矿物形态的影响。模拟结果表明：草酸引起的pH值变化是影响铅矿化结果的最重要参数,体系中的Pb²⁺主要以草酸铅形式沉淀,和原实验结果吻合。此外,只有在弱酸或碱性环境下,且溶液中氟离子浓度大于27 mmol·L^-1时,体系中才会生成氟基磷酸铅。该结果为利用磷酸盐矿物材料进行土壤铅修复提供了理论指导。     

New Isocoumarin Derivatives and Meroterpenoids from the Marine Sponge-Associated Fungus Aspergillus similanensis sp. nov. KUFA 0013

Two new isocoumarin derivatives, including a new 5-hydroxy-8-methyl-2H, 6H-pyrano[3,4-g]chromen-2,6-dione (1) and 6,8-dihydroxy-3,7-dimethylisocoumarin (2b), a new chevalone derivative, named chevalone E (3), and a new natural product pyripyropene S (6) were isolated together with 6, 8-dihydroxy-3-methylisocoumarin (2a), reticulol (2c), p-hydroxybenzaldehyde, chevalone B, chevalone C, S14-95 (4), and pyripyropene E (5) from the ethyl acetate extract of the undescribed marine sponge-associated fungus Aspergillus similanensis KUFA 0013. The structures of the new compounds were established based on 1D and 2D NMR spectral analysis, and in the case of compound 3, X-ray analysis was used to confirm its structure and the absolute configuration of its stereogenic carbons. Compounds 1, 2a–c and 3–6 were evaluated for their antimicrobial activity against Gram-positive and Gram-negative bacteria, Candida albicans ATCC 10231, and multidrug-resistant isolates from the environment. Chevalone E (3) was found to show synergism with the antibiotic oxacillin against methicillin-resistant Staphylococcus aureus (MRSA).     

3种抑菌剂对蛇足石杉内生真菌黑曲霉的抑制效果研究

[目的]探索3种抑菌剂对蛇足石杉内生真菌黑曲霉的抑制效果。[方法]采用平板涂布法分离获得供试菌,用菌丝生长速率法测定3种抑菌剂对黑曲霉的抑制效果。[结果]两性霉素B、苯甲酸钠、肉桂醛对黑曲霉的最低抑菌浓度分别为512.000 00 mg/L、4.00g/L、0.500 00 mg/L;EC50分别为1.910 00、150.000 00、0.120 00 mg/L,EC90分别为88.220 00、730.000 00、0.330 00 mg/L;3种抑菌剂中较优的抑菌剂为两性霉素B。[结论]该研究获得了3种抑菌剂的最低抑菌浓度,为蛇足石杉组织培养的深入研究提供了试验基础。     

木聚糖酶高产菌株的筛选、鉴定及其酶学性质研究

试验以玉米芯粉为唯一碳源,通过富集培养定向筛选技术,从土壤中分离获得一株产木聚糖酶较高的霉菌菌株X-1,经初步液体发酵木聚糖酶活高达724.63 U。依据《真菌鉴定手册》初步鉴定该菌株为黑曲霉(As-pergillus nigeer)。同时对该菌株所产木聚糖酶的酶学性质进行了研究,结果表明:该木聚糖酶的最适作用温度为45℃,最适pH值为6.0;在70℃保温30 min后酶活力仍为90%以上;在pH3.0~7.0范围内稳定性较好,酶活仍为90%以上。     

Development of an Arabidopsis thaliana-based bioassay for investigating seed colonization by mycotoxigenic Aspergillus species

Seeds of Arabidopsis thaliana are hosts for three mycotoxin-producing Aspergillus species, A. flavus , A. nidulans and A. parasiticus, enabling an Aspergillus - Arabidopsis infection (AAI) assay to be developed. The AAI assay involved inoculation of 10- to 12-mg aliquots of uniformly cultivated, surface-sterilized A. thaliana seeds in microcentrifuge tubes. Use of microcentrifuge tubes facilitated qualitative and quantitative analyses of post-infection characteristics such as sporulation and mycotoxin production. Cultivation of A. thaliana seeds under uniform environmental conditions is necessary to limit genotype-independent seed-lot variability. Using the A. nidulans oxylipin mutant, Δ ppoABC , and two well-characterized A. thaliana pathogen-defence mutants, ein2-1 and pad4-1 , the AAI assay permitted genetic analysis of seed infection and mycotoxin production. Sporulation, but not mycotoxin production, was impaired in A. nidulans ΔppoABC , while A. thaliana ein2-1 and pad4-1 had a small but detectable influence on A. nidulans sporulation that appeared to be dependent on seed age.     

叶甲生烟曲霉的初步研究

根据金叶女贞瓢叶甲生曲霉在37℃培养下的生长速度快于25℃和形态学特征等,鉴定为烟曲霉原变种。该菌株对供试的金叶女贞瓢叶甲、大猿叶虫、小猿叶虫均具毒力,其中对金叶女贞瓢叶甲幼虫的毒力可达50%;对大猿叶虫低龄幼虫为40%;对金叶女贞瓢叶甲成虫、大猿叶虫高龄幼虫、小猿叶虫高龄幼虫和低龄幼虫均为30%。该菌株在改良培养基上产孢量较其他培养基可增加2~4倍。