温室黄瓜叶部微生物区系

采用稀释分离法和消毒叶片研磨液培养法对温室黄瓜叶围和内生微生物进行了分离,共分离到248个菌株,初步鉴定出13个属的叶围真菌,其中链格孢属(Alternaria)和青霉属(Penicillium)真菌为优势类群;鉴定出4个属的内生真菌,其中曲霉属(Aspergillus)真菌为优势类群;10个属的叶围细菌,其中芽孢杆菌属(Bacillus)和黄单胞菌属(Xanthomonas)细菌为优势类群;6个属的内生细菌,其中芽孢杆菌属和假单胞菌属(Pseudomonas)细菌为优势类群;6个属的叶围酵母菌,其中隐球酵母属(Cryptococcus)为优势类群;已鉴定出2个属的叶围放线菌,分别为链霉菌属(Streptomyces)和小多孢菌属(Micropolpspora).未分离到内生酵母菌和放线菌.     

粤北一种虫草分离菌的抗酵母现象

CR 95 1 2是一株分离自粤北一种虫草的无孢丝状真菌 ,经培养初步鉴定为无孢菌目(^{Agonomycetales})的丝核菌属 (^Rhizoctonia)。对包括革兰氏阳性及阴性细菌、放线菌、丝状真菌和酵母菌在内的 2 6株致敏菌株的抗性测定表明 ,CR 95 1 2对包括红酵母属 (^Rhodotorula)、酵母属 (^{Saccharomyces})、毕赤氏酵母属 (Pichia)和隐球酵母属 (^Cryptoc     

库木塔格沙漠土壤细菌多样性及具有群体感应抑制活性放线菌筛选

【背景】群体感应抑制剂(quorum sensing inhibitor,QSI)作为抗生素潜在替代品,可有效降低致病菌传染性和毒性。沙漠土壤蕴藏着丰富的放线菌资源,是挖掘群体感应抑制剂的重要来源。【目的】解析库木塔格沙漠土壤细菌群落多样性,筛选并挖掘群体感应抑制活性放线菌资源。【方法】采用Illumina Nova Seq高通量测序技术揭示库木塔格沙漠土壤细菌群落组成,利用可培养方法进行土壤放线菌分离和鉴定;选用紫色杆菌CV026模型筛选群体感应抑制活性放线菌,并对其功能特性进行初步评价。【结果】Illumina Nova Seq高通量测序结果显示,样品土壤细菌涉及23门96目150属,优势菌门为变形菌门(Proteobacteria,61%)、放线菌门(Actinobacteria,28%),其中分枝杆菌属(Mycobacterium)为放线菌门最优势菌属(87.3%),其次为红球菌属(Rhodococcus,6.8%)和丙酸杆菌属(Cutibacterium,0.9%)。可培养方法共分离到108株放线菌,归属9科10属,其中优势菌属为链霉菌属(Streptomyces),占65....     

白豆杉的化学成分分析

白豆杉(pseudotaxus chienii)为我国特有植物,属于红豆杉科(Taxaceae)白豆杉属(pseudotaxus)。本文对白豆杉树皮的化学成分以及就该种植物中是否含有紫杉醇(Taxol)进行分析研究。 并从石油醚提取物中已鉴定出2个化合物,为铁杉树脂醇(Tsugalactone)和1．1．3一三苯基丙烷 (1.1.3-triphenylpropane)。     

河北九莲城淖尔可培养放线菌多样性及抗菌活性筛选

【目的】勘探干涸的九莲城淖尔土壤放线菌多样性并进行活性筛选,以期发现药用微生物资源,为新抗生素的发现奠定基础。【方法】采用15种分离培养基,以稀释涂布法分离放线菌;根据分离菌株的16S rRNA基因序列同源性分析放线菌多样性;发酵液经乙酸乙酯萃取,菌丝体经丙酮浸提,获得提取浓缩物样品;样品通过纸片扩散法进行抗菌活性初筛;抗菌阳性菌株采用PCR技术进行Ⅰ型聚酮合酶(PKS I)KS域、Ⅱ型聚酮合酶(PKS II)KS域和非核糖体多肽合成酶(NRPS)A结构域抗生素生物合成基因的检测。【结果】从11份盐湖土壤样品中分离纯化到251株放线菌,其分布于放线菌纲的10个目15个科31个属,其中优势菌属为链霉菌属和拟诺卡氏菌属;251株放线菌中包括57株耐(嗜)盐放线菌,其优势菌属为拟诺卡氏菌属(22株)和涅斯捷连科氏菌属(15株)。基于16S r RNA基因序列的系统发育分析显示,菌株J11Y309为糖霉菌科潜在新属,菌株J12GA03为分枝杆菌科潜在新种。96株放线菌活性检测结果显示,56株至少对1株检定菌具有抗菌活性,阳性率为58.3%;56株有活性的放线菌中,47株至少含有1种抗生素生物合成基因,其中17株同时具有3种抗生素生物合成基因。【结论】干涸的九莲城淖尔土壤中含有较为丰富的药用放线菌资源,具有从中发现放线菌新物种和新抗生素的潜力。     

一株产钙调磷酸酶抑制剂链霉菌CZW-15的

【目的】筛选产钙调磷酸酶抑制剂的放线菌菌株。【方法】通过酵母报告基因(CDRE::LacZ)高通量筛选模型与人体钙调磷酸酶试剂盒检测相结合的方法,从土壤放线菌中筛选产钙调磷酸酶抑制剂的菌株;根据形态和培养特征、生理生化实验以及16S rRNA基因序列比对进行菌株鉴定;采用单因素实验和正交实验对发酵条件进行优化。【结果】从土壤中筛选得到一株产高活性钙调磷酸酶抑制剂的放线菌CZW-15,经鉴定属于链霉菌属(Streptomyces)。酵母报告基因检测显示其发酵上清液对依赖酵母钙调磷酸酶的报告基因表达抑制活性IC50为7.4 mL/L,而对照药物FK506的IC50为65 μg/L。该菌的最佳摇瓶发酵配方为(%)：玉米粉2、酵母粉0.1、K2HPO4 0.04、MgSO4 0.04、NaCl 0.05、FeSO4 0.001;发酵条件为：初始pH 7.5,温度28 °C,转速180 r/min,装液量50 mL/250 mL,接种量4%,培养时间4 d。优化后1.5 μL发酵上清液对依赖酵母钙调磷酸酶的报告基因表达抑制活性达到117%,比优化前提高4.5倍。【结论】CZW-15属于链霉菌属,该菌产生高活性的抑制酵母钙调磷酸酶的活性物质。     

西沙海藻共附生放线菌的分离鉴定及其抗菌活性评价

【目的】为了探究南海海藻共附生放线菌资源的多样性及潜在的应用价值,对中国西沙群岛来源的海藻进行共附生放线菌的分离鉴定与抗菌活性筛选。【方法】利用稀释涂布平板法,采用2种不同分离培养基对不同采样位点的6种海藻进行放线菌分离;通过16S rRNA基因序列分析、构建系统发育树对分离的放线菌进行鉴定;用打孔法对无乳链球菌(Streptococcus agalactiae)等10种敏感细菌进行抗菌活性筛选;对筛选得到的目标活性菌株HZ014进行全基因组测序,通过AntiSMASH在线工具分析其次级代谢产物生物合成基因簇,预测其产生新型活性物质的潜力。【结果】从6种海藻中分离得到36株共附生放线菌,基于16S rRNA基因序列比对和系统发育分析,鉴定结果为链霉菌属(Streptomyces) 2株、红球菌属(Rhodococcus) 2株、诺卡氏菌属(Nocardia)3株、小单孢菌属(Micromonospora) 5株和盐孢菌属(Salinispora) 24株;抗菌活性筛选结果表明,36株共附生放线菌发酵粗提物对至少1种敏感细菌表现出一定的抑制作用,不同菌株发酵粗提物的抗菌活性存在明显差异,...     

葡萄果粒表皮酵母菌多样性研究

从新疆、甘肃、陕西、宁夏、山东主要酿酒葡萄产区收集葡萄果粒并分离得到酵母258株, 利用26S rDNA的D1/D2区序列分析并结合形态学、生理学特征对这些菌株进行了分类学研究, 探讨了这些地区葡萄果粒表皮酵母的物种多样性及其分布。共鉴定出13属26种, 其中优势属为汉逊酵母属Hanseniaspora(5种), 假丝酵母属Candida(4种), 毕赤酵母属Pichia(4种)和伊萨酵母属Issatchenkia(2种)。对分离自不同地域的同种内不同菌株进行了D1/D2序列分析比较, 以探讨不同地理起源地酵母种内序列稳定性及其变异。     

三七内生放线菌的分离及拮抗三七根腐病原活性研究

挖掘云南文山三七内生放线菌菌种资源以及对分离到的放线菌菌株进行三七根腐病病原菌的抗菌活性评价，为生物防治三七根腐病的发生、传播、有效治理及解决三七连作障碍和后续研究三七内生放线菌的代谢产物提供菌种资源。采用三种分离方法、六种分离培养基对文山两个产地三七全株植物进行内生放线菌分离，分离到的菌株通过16S rRNA基因扩增测序鉴定到属，通过琼脂扩散法对菌株发酵液进行抗菌活性初筛。共分离到56株内生放线菌，经形态特征初步排重后，选22株代表菌株进行16S rRNA基因扩增测序，并鉴定到属，其分属于链霉菌属(Streptomyces)、放线产孢菌属(Actinomycetospora)、拟诺卡氏菌属(Nocardiopsis)、黄英菌属(Yinghuangia)四个属。对23株菌株发酵液进行抗菌活性初筛，14株菌株(60.87%)具有不同程度的抗菌活性，其中菌株S004、S006、S014、S016、S022、S042、S047、S053对三七根腐病病原菌有较好的抗菌活性，具备进一步深入研究的价值。本研究初步探索出适合三七内生放线菌分离的分离方法，获得一批三七内生放线菌菌种资源，并筛选出8株对...     

丹参植株内生菌的分离纯化及其抗病性研究

为探明丹参(Salvia miltiorrhiza Bge)内生菌的种类,筛选拮抗农作物病害菌的生防菌株,从健康丹参植株中进行内生菌分离,依照形态特征以及16SrDNA序列对菌株进行初步分类鉴定,采用琼脂块法进行拮抗菌株筛选,并选取拮抗活性较强的菌株液体发酵进行体外抑菌试验。结果表明:(1)从丹参植株中共分离得到69株内生菌(真菌62株、放线菌7株),其中23株内生真菌属于无孢类群或现有条件不适合产孢,其余真菌菌株中串珠镰孢菌属(Fusarium moniliforme Sheld.)和交链孢菌属(Alternaria sp)为优势菌群;7株内生放线菌均为链霉菌属。(2)病原菌拮抗性实验表明,有44株内生菌对病原菌具有不同程度的拮抗活性,其中12株内生菌对2种及以上靶标病原菌具有拮抗活性,表明丹参内生菌具有一定的广谱抗菌性。(3)放线菌菌株A232的次级代谢产物对白色假丝酵母(Canidia albicans)和苹果腐烂菌(Valsa mali)都表现出较强的拮抗活性,通过形态、培养特征以及16SrDNA序列分析,鉴定其为Streptomyces luteoverticillatus。     

复合保水材料对苗木生长的影响

为探索保水剂与外源物质配比形成的复合保水材料对苗木生长的影响,以2年生核桃(Juglans regia)、山杏(Prunus armeniaca)、刺槐(Robinia pseudoacacia)和杨树(Populus sp.)幼苗为实验材料进行盆栽正交实验,以苗木的生长因子(叶面积和新梢生长高度)来评价复合保水材料对苗木的影响。结果表明,不同复合保水材料均能促进苗木的生长,在实验保水剂用量范围保水剂用量增加促进效果增大。杨树最佳配方为处理15(保水剂20g,聚天门冬氨酸1.0g,复合肥0g,土壤含水量7%),在此处理下杨树叶面积比对照增长48%,新梢生长高度比对照增长21%。核桃、山杏、刺槐的最佳配方分别为处理3(保水剂20g,聚天门冬氨酸1.5g,复合肥15g,土壤含水量12%)、处理6(保水剂15g,聚天门冬氨酸0.5g,复合肥0g,土壤含水量12%)、处理10(保水剂15g,聚天门冬氨酸0g,复合肥15g,土壤含水量7%)。     

Synthesis and characterization of a novel cellulose-g-poly(acrylic acid-co-acrylamide) superabsorbent composite based on flax yarn waste

A new, low-cost, and eco-friendly cellulose-based superabsorbent was successfully prepared from flax yarn waste. The method used was a free-radical graft copolymerization of AA and AM onto a cellulose backbone in a homogeneous aqueous solution. APS was used as the initiator in the presence of a crosslinker, MBA. The effects of various factors on water absorbency were discussed. The factors included reaction temperature, initiator amount, monomer amount, salt solution type, and solution pH. Under the optimized conditions, the water absorbencies of the obtained superabsorbent composite were 875 g/g distilled water, 490 g/g natural rainwater, and 90 g/g 0.9 wt% aqueous NaCl solution. The product also had excellent water retention and salt resistance properties. Fourier-transform infrared spectroscopy and scanning electron microscopy were employed to examine the structure of the prepared superabsorbent.     

Utilization of starch and clay for the preparation of superabsorbent composite

Starch and attapulgite were utilized as raw material for synthesizing starch-graft-poly(acrylic acid)/attapulgite superabsorbent composite by graft copolymerization reaction of starch and acrylic acid (AA) in the presence of attapulgite micropowder in aqueous solution. Major factors affecting on water absorbency such as weight ratio of AA to starch, initial monomer concentration, neutralization degree of AA, amount of crosslinker, initiator and attapulgite were investigated. The superabsorbent composite synthesized under optimal synthesis conditions with an attapulgite content of 10 wt% exhibit absorption of 1077 g H(2)O/g sample and 61 g H(2)O/g sample in distilled water and in 0.9 wt% NaCl solution, respectively. This superabsorbent composite with excellent water absorbency and water retention under load, being biodegradable in nature, economical and environment-friendly, could be especially useful in agricultural and horticultural applications.     

Analysis of Water Sorption Isotherms of Superabsorbent Polymers by Solution Thermodynamics

Water sorption isotherms of superabsorbent polymers were measured, and their affinity for water was evaluated by solution thermodynamics. The results provide basic data for the functional packaging of food to control the water content of food during its transportation or storage. Water activity above 0.9 was measured by adding a specific amount of water to the samples, while that below 0.9 was measured with apparatus for evaluating water sorption isotherms. Thus, water sorption isotherms for superabsorbent polymers were obtained up to a water activity of approximately 0.98. The amount of water sorbed by the superabsorbent polymers was influenced by the type of functional groups in the polymers, and not by the degree of cross-linking in the polymers. The integral Gibbs free energy, which is the most suitable parameter for evaluating the affinity of a material for water, was evaluated from the water sorption isotherms by using solution thermodynamics.     

Application of zeolite and geohumus superabsorbent on establishment and some growth indices of Nitraria schoberi L.

Using Superabsorbent is one of the solutions to water shortages in arid and semi-arid regions. In order to evaluate the effect of zeolite and geohumus on the growth of Nitraria schoberi L. species, a factorial experiment in a completely randomized design was conducted with nine replications in Kashan city. The treatments consisted of various zeolite levels (0, 10 and 15 wt%) and geohumus (0, 100, 150, 250 gr for hole) and irrigation (normal irrigation, low irrigation). This study showed that superabsorbent application has a positive effect on establishment and other indices such as plant height, large and small canopy diameter and collar diameter. The highest survival percentage was observed in superabsorbent application (100%) and the lowest was measured in control treatment of low irrigation (the soil free of modifying substances) (78%). Also, the most growth indices of the plant are related to the treatment of 250 g geohumus with low irrigation treatment. Based on the results, it was found that adding superabsorbent on soil causes more establishment and improves vegetative growth traits. Also, considering the economical price of zeolite superabsorbent compared to geohumus as well as its abundance in Iran, it is recommended to use in order to increase irrigation intervals and reduce costs in desertification projects.     

Synthesis of wheat straw-g-poly(acrylic acid) superabsorbent composites and release of urea from it

Wheat straw (WS) was used as raw material for synthesizing a novel wheat straw-g-poly(acrylic acid) (WS/PAA) superabsorbent composite by graft polymerization with wheat straw powder and acrylic acid in aqueous solution. The effect of wheat straw on water absorbency was discussed and the highest water absorbency was obtained when the amount of wheat straw in the feed was 20%. The superabsorbent composite was characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The results of FTIR spectra showed OH of WS participated in graft polymerization with acrylic acid. The influences of pH, cations and anions on equilibrium water absorbency of WS/PAA were investigated. The superabsorbent composite was swollen in aqueous solution of urea to load urea, and the results showed urea concentration had no obvious effect on the swelling behaviors of WS/PAA. Furthermore, the release of urea from loaded WS/PAA was analyzed in water and in soil. Urea diffusion coefficient D was calculated.     

Synthesis,characterization and swelling behaviors of sodium alginate-g-poly(acrylic acid)/sodium humate superabsorbent

A novel sodium alginate-g-poly(acrylic acid)/sodium humate superabsorbent was prepared by graft copolymerization with sodium alginate, acrylic acid and sodium humate in aqueous solution, using N,N’-methylenebisacrylamide as a crosslinker and ammonium persulfate as an initiator. The effects of crosslinker, sodium alginate and sodium humate content on water absorbency of the superabsorbent were studied. The swelling behavior in solutions of various pH and the swelling kinetics in saline solutions (5 mmol/L NaCl and CaCl₂) were also investigated. The results from IR analysis showed that both sodium alginate and sodium humate react with the acrylic acid monomer during the polymerization process. The introduction of sodium humate into the sodium alginate-g-poly(acrylic acid) system could enhance the water absorbency and the superabsorbent containing 10 wt% sodium humate acquired the highest water absorbency (1380 g/g in distilled water and 83 g/g in 0.9 wt% NaCl solution).     

Sugarcane bagasse derivative-based superabsorbent containing phosphate rock with water-fertilizer integration

To improve the water-fertilizer utilization ratio and mitigate the environmental contamination, an eco-friendly superabsorbent polymer (SPA), modified sugarcane bagasse/poly (acrylic acid) embedding phosphate rock (MSB/PAA/PHR), was prepared. Ammonia, phosphate rock (PHR) and KOH were admixed in the presence of acrylic acid to provide nitrogen (N), phosphorus (P) and potassium (K) nutrients, respectively. Impacts on water absorption capacity of the superabsorbent polymer (SAP) were investigated. The maximum swelling capacity in distilled water and 0.9wt.% (weight percent) NaCl solution reached 414gg(-1) and 55gg(-1) (water/prepared SAP), respectively. The available NPK contents of the combination system were 15.13mgg(-1), 6.93mgg(-1) and 52.05mgg(-1), respectively. Moreover, the release behaviors of NPK in the MSB/PAA/PHR were also studied. The results showed that the MSB/PAA/PHR has outstanding sustained-release plant nutrients property.     

Influence of salts and phenolic compounds on olive mill wastewater detoxification using superabsorbent polymers

For a selection of nine commercially available superabsorbent polymers, the absorption capacity was evaluated for the principal absorption-inhibition constituent of OMW, mineral salts and for phytotoxic-components, the phenolic compounds. A double exponential model was established for electrical conductivities ranging 4.2-25,000 microS cm(-1). For solutions of phenolic compounds ranging 0-0.5 g l(-1), a distribution coefficient near unit was achieved, while for OMW, the phenolic compounds were concentrated inside the gel as the distribution coefficient was 1.4. Correction of OMW pH towards neutrality was found to increase the absorption capacity by up to 35%. The phytotoxicity was assessed by the germination of Lepidium sativum. Inhibition in plant growth occurred for all OMW dilutions without superabsorbent polymers application. For 5% of OMW (COD 5 gl(-1) and 200 ppm of phenolic compounds) immobilised in PNa2 (1 gl(-1)), plant growth was promoted being observed a 120% growth germination, thus indicating that olive mill wastewater detoxification occurred.     

Synthesis of a novel superabsorbent hydrogel by copolymerization of acrylamide and cashew gum modified with glycidyl methacrylate

Novel superabsorbent hydrogels were manufactured using chemically modified cashew gum (CGMA) and acrylamide (AAm) as reactants. The route for the synthesis was feasible due to the incorporation of glycidyl methacrylate (GMA) into structure of cashew gum (CG) to form the cashew gum-methacrylated (CGMA), in an appropriate mixture water-DMSO, as solvent, and using TEMED as catalyst. Thereafter, the CGMA was copolymerized with AAm yielding (CGMA-co-AAm) hydrogels. The main characteristics of raw and the modified materials are reported in this paper. ¹³C NMR, ¹H NMR and FTIR spectroscopies confirmed the incorporation of vinyl groups, from GMA, into CG structure. By the spectrophotometry analyses, it was found that, ca. 82% of GMA was incorporated to the CG after 24 h of reaction. The cross-linking of CGMA or co-polymerization of CGMA with acrylamide leads to a hydrogel formation. Their gelation was characterized by FT-IR analysis. Alkaline hydrolysis at 40 °C for 3 and 4.5 h increased the water uptake (WU) capacity. Hydrolyzed CGMA-co-AAm hydrogels present higher values of WU (up to 1500) and may be classified as water superabsorbent material. Applications in agriculture, as soil conditioner, and in biomedical field, as biomaterial (scaffold) are being investigated.