广西涠洲岛3种海参共附生细菌多样性及其延缓衰老活性分析

【目的】明确广西涠洲岛海参共附生细菌多样性，筛选出具有延缓衰老活性的菌株，为挖掘延缓衰老活性的新化合物提供菌种资源。【方法】选用9种选择性培养基对来源于广西涠洲岛的3种海参［异色哈威参（Havelockia versicolor）、玉足海参（Holothuria leucospilota）和方柱翼手参（Colochirus quadrangularis）］共10份样品进行共附生细菌分离纯化，基于16S rRNA测序分析其多样性，并以秀丽隐杆线虫（Caenorhabditis elegans）为模型评价共附生细菌发酵粗提物的延缓衰老活性。【结果】从广西涠洲岛3种海参中共分离获得63株共附生菌株，隶属于3门4纲14目25科35属，以放线菌纲（Actinobacteria）为优势菌群，共有31株（占49.21%）；放线菌GXIMD LM0085和GXIMD LM0159有可能为潜在新种，与对应有效发表菌株Kocuria assamensis、K.salsicia的相似性分别为97.38%和97.00%。不同培养基分离获得的海参共附生细菌在属类水平上存在明显的数量差异，以M9培养基分离获得的菌属数量最多（19属28株），P7培养基分离获得的最少（仅6属6株）；在筛选确定的35属细菌中，仅Cobetia和嗜盐单胞菌属（Halomonas）在9种培养基均有生长分布，多达13个属仅在单一的培养基中生长。不同海参分离获得的共附生细菌数量排序为1#异色哈威参>方柱翼手参>2#异色哈威参>玉足海参，除了玉足海参外，其他3只海参体内的共附生放线菌相对丰度明显高于体表共附生放线菌相对丰度。线虫寿命试验发现，有6株共附生细菌的发酵粗提物能显著延长秀丽隐杆线虫寿命（P<0.05），分别是GXIMD LM0037（寡养单胞菌属）、GXIMD LM0005（链霉菌属）、GXIMD LM0071（副球菌属）、GXIMD LM0114（寡养单胞菌属）、GXIMD LM0099（原小单孢菌属）和GXIMD LM0032（短状杆菌属）。【结论】广西涠洲岛海域海参蕴含着多样性丰富的共附生细菌资源，具有潜在的新物种，且部分菌株具有延缓衰老活性，在延缓衰老活性物质挖掘及新型抗衰老药物研发方面具有巨大潜力。     

硫酸盐还原菌的筛选及生理特性研究

[目的]为使用硫酸盐还原菌处理废水提供理论依据。[方法]利用硫酸盐还原菌选择培养基从生产赤霉素产生的废水中筛选硫酸盐还原菌。依据不同菌株对硫酸根的降解效率,对筛选出的菌株进行复筛。选取对硫酸盐降解效果最好的菌株,研究温度、pH值、接种量等对其生理活性的影响。[结果]从供试废水中共筛选出8种硫酸盐还原菌,其对硫酸根的降解效率为26.22%～87.75%。经综合分析,确定8号菌株为优势菌;不同接种量对其硫酸盐降解效率影响不大;温度和pH值对硫酸盐还原菌的影响较大,最适温度和pH值分别为35℃和7.5。[结论]8号菌株为优势菌,在最适条件下其对污水中硫酸盐的去除率达80%以上。     

一株寄生柑橘介壳虫真菌的分离与鉴定

从感病柑橘介壳虫中分离和鉴定了一株菌株,为球黑孢霉菌[Nigrospora sphaerica(Sacc)Mason]。菌株在20~35℃范围内均能生长,25~30℃是菌落生长的最适温度区域。病菌在以淀粉为碳源的培养基上菌丝生长量较大,且菌丝生长丰度高。该菌对果糖、麦芽糖、乳糖、淀粉和葡萄糖为碳源的培养基的利用率均较高。该菌在以硫酸铵为氮源的培养基上菌丝生长量较大,其次是硝酸铵、甘氨酸和赖氨酸。     

Vitamin C-induced increase of dermatan sulfate in cultured Hurler's fibroblasts

In fibroblasts taken from patients witli Hurler's syndromne and grown in cultlure, dermatan sulfate constituted a larger percentage of the total sulfated glycosaminoglycans than it did in cultured fibroblasts from unaffected individuals. Moreover, the addition of ascorbic acid (vitamnin C) to the culture medium markedly increased the concentration of dermatan sulfate in the Hurler's fibroblasts but not in the normal fibroblasts. The biochemical phenotype of the Hurler's cells persisted during 28 weeks of serial culture.     

The diversity and potential function of endophytic bacteria isolated from Kobreasia capillifolia at alpine grasslands on the Tibetan Plateau,China

A total of 50 endophytic bacterial isolates were obtained from Kobreasia capillifolia at alpine grasslands in the Eastern Qilian Mountains on the Tibetan Plateau in China. Based on the sequencing and phylogenetic analysis of 16 S r DNA genes, all isolates phylogenetically related closely to Bacillus, Acinetobacter, Stenotrophomonas, Brevundimonas, Arthrobacter, Curtobacterium, Paenibacillus, Plantibacter, Promicromonospora, Serratia, and Microbacterium, among which Bacillus was the predominant genus(47.8% of the total number of endophytic isolates). These isolates possessed different biological functions. In 50 endophytic bacteria, 42 isolates produced indole acetic acid(IAA) on King medium. There were seven isolates showing potency of mineral phosphate solubilization in Pikovaskaia's(PKO) liquid medium. Seven isolates exhibited antagonistic effect against Fusarium avenaceum, Colletotrichum coccodes and Phoma foveata. This was the first report on diversity and plant growth promotion of endophytic bacteria from K. capillifolia on alpine grassland in the Eastern Qilian Mountains, Chain. It is essential for revealing the relationship among plant, microorganism, and the special environment because the potential function of endophytic bacteria made a contribution to the interactions of plants and endophytic bacteria.     

Relationship between potassium chloride suppression of corn stalk rot and soil microorganism characteristics

Observations from a site-fixed field trial of 12 years in Jilin Province show that potassium chloride (KCl) application has a significant positive influence on corn stalk rot incidence. Incubation experiments were conducted to study the effects of KCl and soil extracts on the growth of Fusarium graminearum, the most common stalk rot fungi in this area, and the population changes in rhizosphere fungi, bacteria and actinomyces at different growth stages of corn. The results show that KCl addition to the potato dextrose agar (PDA) medium could not directly suppress Fusarium graminearum development. Soil extracts from soil samples taken from the field plots with and without KCl application affected Fusarium graminearum development, with soil extracts with KCl treatments suppressing Fusarium graminearum development more significantly, compared with that from the KCl-free treatment. These results indicate that soil extracts play a role in the interaction between corn and Fusarium graminearum. Long-term KCl application may increase the populations of rhizosphere fungi and actinomyces in the early growth stages, while there is no significant difference in the number of bacteria in rhizosphere among the treatments. Also, the populations of rhizosphere fungi are negatively correlated with the incidence of stalk rot in the early growth stages of corn. The sensitive infection stages of pathogen to corn consist of the stages when there is significant difference in the populations of rhizosphere fungi and actinomyces. The change of microorganism populations (especially fungi) in soil may be associated with the incidence decrease and is one of the mechanisms of KCl suppressing corn stalk rot. Translated from Plant Nutrition and Fertilizer Science, 2007, 13(2): 279–285 [译自: 植物营养与肥料学报]     

Selective release of enzymes from bacteria

A group of hydrolytic enzymes, including phosphatases and nucleases, is selectively released from E. coli and certain other Gram-negative bacteria by a process designated as osmotic shock. This procedure involves exposure of the cells to ethylenediaminetetraacetate (EDTA) in 0.5 molar sucrose followed by a sudden osmotic transition to cold, dilute MgCl(2). Osmotic shock also results in an alteration of the permeability barrier of the bacterial cell and a depletion of the pool of acid-soluble nucleotides, but there is no loss of viability. On being restored to growth medium, the shocked cells recover after a lag period. Formation of spheroplasts by treatment with EDTA and lysozyme leads to selective release of the same group of enzymes. We believe that the selectively released enzymes are confined in a region between the bacterial cell wall and the cytoplasmic membrane. Histochemical studies indicate such a localization. Further, the enzyme activities are measurable with intact cells, even when the substrate is a nucleotide, to which whole cells are impermeable. Another piece of evidence concerns a mutant E. coli with a defective cell wall. In contrast to normal bacteria, this organism loses one of these enzymes into the medium in the course of growth. After osmotic shock, the bacteria show reduced uptake of sulfate,betagalactosides, galactose, and certain amino acids. Furthermore, the shock treatment causes the release of nondialyzable factors able to bind sulfate, galactose, and the same amino acids. A possible interpretation of these observations is the following: the binding proteins occupy sites near the bacterial surface, and they may be components of active transport systems responsible for the concentrative uptake of these nutrients.     

降解秸秆的细菌和放线菌的分离与筛选

用秸秆粉部分代替LB、高氏培养基中的碳源,通过延长培养时间从土样中分别富集降解秸秆的细菌、放线菌,用稀释倒平皿挑取单菌落法通过菌落形态差异分离出细菌29株、放线菌29株。用秸秆粉培养基定性鉴别法鉴别出其中有8株细菌、10株放线菌能降解秸秆。测试了硝酸铵、酵母粉和土壤浸液等添加物对能降解秸秆的细菌和放线菌在秸秆粉培养基上生长的影响。结果表明,酵母粉对细菌的生长具有明显促进作用,其他添加物对供试菌的生长影响较小。     

水稻白叶枯病菌hisF基因的克隆及功能初析

根据黄单胞菌hisF基因的同源性设计简并引物,采用PCR方法从水稻白叶枯病菌(Xanthomonas oryzae pv.oryzae,Xoo)中克隆了hisF同源基因,命名为hisFXoo.NCBI网站蛋白质保守结构域搜索表明,HisFXoo属于组氨酸生物合成蛋白家族的一员,具有与其他HisF蛋白相似的结构.序列比较显示,该基因在黄单胞菌中是相对保守的.同源性搜索比较显示,与水稻条斑病菌(Xoryzae pv.oryzicola,Xooc)的hisF(登录号:DQ372107)同源性高达98%.通过同源重组的方法,构建了hisFXoo的插入突变体,在NA+Amp平板上筛选后,并且经过PCR及Southern杂交验证插入正确.在MMX基本培养基中生长测定发现,hisF突变体生长能力明显下降,证明hisF基因与Xoo生长代谢相关.但是,该突变体仍具有致病性,并且毒力与野生型菌株没有明显差异.     

4种常用杀菌消毒剂对养殖水体中硝化细菌生长的影响

[目的]为调节和改善养殖微生态环境平衡和合理用药提供科学依据。[方法]以分离自养殖水体的硝化细菌为试验材料,运用生态毒理学的方法,在实验室条件下研究常用杀菌剂二氧化氯、高锰酸钾、甲醛、硫酸铜与硫酸亚铁合剂对其生长的影响。[结果]0.1mg/L二氧化氯、0.6 mg/L高锰酸钾、20 mg/L甲醛、0.7 mg/L硫酸铜与硫酸亚铁(5∶2)合剂对硝化细菌生长的影响较小,同时对水体中的病原微生物有较好的防治效果。[结论]在水产养殖中,应选用适宜浓度的杀菌剂对水体进行消毒。     

双孢蘑菇废菌渣不发酵连栽姬松茸配套技术研究

利用双孢蘑菇废菌渣不发酵直接连栽姬松茸,结果表明:4月15日播种的姬松茸产量为3.41kg·m-2,分别比3月15日和4月1日播种增产8.20％、3.31％;姬松茸不同营养配方平均产量差异达极显著水平,以大豆粉1.0 kg、酵母粉0.25 kg、硫酸铵0.2 kg的营养配方,菌丝生长速度最快,菌丝浓白;以大豆粉1.5 ...     

22种中草药对畜禽常见肠道病原菌的体外抑菌作用

对22种中草药对常见畜禽肠道病原菌的抗菌活性进行了定量分析.采用水煎法提取中草药有效成分,通过体外抑菌试验检测不同提取成分的抑菌活性,确定其体外最小抑菌浓度(MIC).结果表明:对9种常见肠道病原菌(大肠杆菌(O2、O8、O78、O139)、猪伤寒沙门氏菌、猪霍乱沙门氏菌、鸡伤寒沙门氏菌、鸡白痢沙门氏菌、鼠伤寒沙门氏菌)抑菌圈最大的为黄芩、五倍子、乌梅,其抑菌圈直径在15～25mm,其次为诃子、大黄、草河车,其抑菌圈直径在10～20mm;五倍子、诃子、黄芩、乌梅最小抑菌浓度在0.031～0.125g/mL,石榴皮、地榆、黄连、大黄、艾叶最小抑菌浓度在0.031～0.250g/mL.说明22种中草药对上述细菌具有不同程度的抑菌效果,尤以五倍子、诃子、黄芩、地榆、乌梅较其他中草药的抑菌效果更佳(P<0.05).     

两种阿魏提取物对白灵菇菌丝生长的影响

通过白灵菇菌丝在含臭阿魏和香阿魏提取物培养基上的生长试验,探讨了两种阿魏提取物培养基与常规PDA培养基对白灵菇菌丝生长影响的差异性,及两种阿魏不同浓度提取物对白灵菇菌丝生长的影响.结果表明,[WTHZ]含两种阿魏提取物的培养基对白灵菇母种菌丝生长有明显的促进作用,均优于常规PDA培养基,臭阿魏促进菌丝生长的适宜提取物浓度为24 g/L,菌丝平均长速为0.55 cm/d,香阿魏为18 g/L,日平均生长量达到0.65 cm,常规PDA培养基菌丝日平均生长量只有0.21 cm,香阿魏比臭阿魏的促进作用更加显著.[WTBZ]     

20种有毒植物的不同提取物对玉米弯孢叶斑病菌的抑菌活性测定

用生长速率测定法，测试了长白山20种有毒植物的不同溶剂提取物对玉米弯孢叶斑病菌（Curvularia lunata Boed．）的离体抑制活性．结果表明，供试20种有毒植物的不同溶剂提取物在稀释1000倍的情况下，艾蒿正丁醇提取物对供试病原菌的菌丝生长抑制率最高（81．01％），藜芦生物碱提取物与延胡索氯仿提取物也表现出较高的活性。     

Triacontanol: a new naturally occurring plant growth regulator

Alfalfa meal and chloroform extracts of the meal have increased the growth and yield of several plant species. A crystalline substance isolated from the active fraction of alfalfa meal increased the dry weight and water uptake of rice seedlings when sprayed on the foliage or applied in nutrient culture. The substance was identified as triacontanol by mass spectrometry. Sprays containing this compound also increased the growth of corn, and barley grown in soil. Authentic triacontanol produced a similar response over a wide range of concentrations on rice grown in nutrient cultures and tomatoes grown in soil.     

金黄色葡萄球菌耐盐生长的形态观察及机理的初步研究

 为阐明金黄色葡萄球菌特有的耐盐生长特性的机理,试验将该菌分别培养于含低盐（1.0％NaCl）和高盐（10.0％NaCl）的LB液体培养基及卵黄琼脂培养基,观察发现高盐液体条件下该菌呈絮状生长,细菌个体形态明显增大,在高盐固体条件下菌落形态较小,菌落形成单位（CFU）数量也明显减少;对菌体裂解产物进行十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）分析,发现金黄色葡萄球菌在高盐与低盐培养条件下的蛋白表达谱存在差异,前者比后者被诱导多表达出至少一个蛋白质条带（MW 22ku）;将相同数量的该菌接种于含05IU/mL青霉素作为细胞壁合成抑制剂及不同氯化钠浓度（1.0%,2.5%,4.0%,5.5%,7.0%,8.5%和10.0%）的卵黄琼脂培养基上培养,发现随着NaCl浓度的升高,CFU数量逐渐减少。结果表明,金黄色葡萄球菌的耐盐生长特性与其细胞壁合成和盐应激蛋白表达有关,并伴随有菌落、菌体形态的变化。     

Human lupus inclusions and interferon

Raji cells, a human B lymphoblastoid cell line of Burkitt lymphoma origin, formed lupus inclusions when grown in a medium conditioned by the growth of Raji cells whose DNA thymidine residues had been unifilarly (single-strandedly) substituted with bromodeoxyuridine. Ultracentrifugation of this medium in excess of that required to remove Epstein-Barr virus and all other known mammalian viruses did not prevent the formation of the inclusions, and treatment of the conditioned medium with pronase destroyed the activity. These results demonstrate the presence of a protein that is secreted from bromodeoxyuridine-substituted Raji cells and is capable of inducing nonbromodeoxyuridine-substituted cells to form lupus inclusions. Interferon (100 units per milliliter) was found in the conditioned medium. Inclusions also formed in Raji cells grown in fresh medium supplemented with human leukocyte or fibroblast interferon (100 units per milliliter).     

Bacterial origin of luminescence in marine animals

Bacterial luciferase activity was detected in light organ extracts of squids, fishes, and pyrosomes, suggesting that these systems are derived from bacteria-animal symbioses. In none of these cases was it possible to culture luminouis bacteria. Analyses of the decay kinetics show that the luciferases from the squid, ceratioid, and pyrosome light organs are all similar to bacterial luciferases from the genus Photobacterium, while those from the anomalopid light organs are different.     

中期施肥对栝楼果实产量与品质的影响

通过6种化肥的大田试验,探讨了中期施肥对栝楼果实产量、质量、浸出物、可溶性糖、粗多糖和灰分含量的影响.结果表明:磷酸二铵和硫酸钾复合肥对栝楼果实产量增长作用显著,较对照分别增加了104.7％和79.86％;磷酸二铵、硫酸钾复合肥、硫酸钾和磷酸二氢钾对栝楼果实水溶性浸出物含量增加具有一定作用;6种化肥均对醇浸出物含量有不...     

6种植物提取物的抑菌活性研究

[目的]研究大蒜、石榴、苍耳等6种植物提取物对几种常见蔬菜病害病原菌的抑制作用。[方法]采用生长速率法测定6种植物丙酮抽提物对病原菌菌丝生长的抑制效果,并进一步开展大蒜粉、苍耳提取物防治番茄早疫病的田间试验。[结果]大蒜、石榴提取物对多种植物病原菌的菌丝都有明显的抑制作用;苍耳次之;辣椒提取物主要抑制黄瓜炭疽病菌和番茄早疫病菌;蒲公英提取物主要对黄瓜炭疽病有抑制作用;侧柏叶对黄瓜白粉病菌的抑制率较高。1.5%大蒜粉防治番茄早疫病效果较好,防效均在95%以上;其中,以2 000倍效果最佳,对成株期番茄早疫病的防治效果达99.40%。[结论]6种植物提取物中,大蒜提取物的抑菌活性最强,1.5%大蒜素粉剂对番茄早疫病的防治效果最佳。