块菌(松露)宿主可培养内生菌群落结构与多样性研究

探究四川凉山彝族自治州块菌主产区华山松内生菌群的结构及多样性。在会东县选取4个点(新田乡、新云乡、淌塘镇、雪山乡)的块菌宿主华山松的根、茎、叶为实验材料,通过不同培养基分离样品根、茎、叶的内生细菌、真菌、放线菌,DNA分子鉴定分离菌株的种属,最终分离得到细菌46株,其中欧文氏菌属(Erwinia)5株,沙门氏菌属(Salmonell)1株,杆菌属(Bacillus)22株,葡萄球菌属(Staphylococcus)2株,假单胞菌属(Pseudomonas)2株,类芽胞杆菌属(Paenibacillus)2株,布丘氏菌属(Buttiauxella)2株,肠杆菌属(Enterobacte)3株,爱文氏菌属(Ewingella)1株,泛菌属(Rahnella)1株,拉恩氏菌属(Rahnella Izard)2株,其他属3株;真菌19株,均为子囊菌门(Ascomycota),其中青霉属(Penicillium)4株,疱霉属(Phoma)1株,子囊菌门未知菌1株,篮状菌属(Cladosporium)1株,分枝孢子菌属(Sydowia)1株,曲霉属(Aspergillus)1株,其他属10株;放线菌33株,为链霉菌属(Streptomyces)22株,短小杆菌属(Curtobacterium)2株,短杆菌属(Brevibacterium)1株,其他属8株。研究结果表明,来自不同地点、不同植株部位、不同培养基分离得到的块菌宿主华山松内生菌有差异,证实微生物在土壤、块菌、宿主植物之间有着复杂的相互作用,为块菌的人工栽培提供参考。     

云南黑松露及其共生松根的物质及通路关联分析

松露必须与植物共生形成外生菌根,通过与菌根进行物质互利交换才能形成子实体。【目的】云南黑松露(Tuber sinense, SL)多与云南松(Pinus yunnanensis)共生,探明云南松露与其共生松树的物质交流。【方法】应用液相质谱(liquid chromatograph mass spectrometer, LC-MS)技术,对新鲜的云南黑松露及云南松松根(Pinus yunnanensis roots, SG)的代谢物谱进行分析。【结果】在SL及SG中分别检测到1 304个和1 516个物质,其中SL特有物质(Tuber sinense specificity, SLS) 399个,SG特有物质(Pinus yunnanensis roots specificity, SGS) 611个;二者共有的显著差异物质294个,包括SL上调物质(differential metabolites-up, DEMs-up) 93个,SL下调物质201个。网络相关分析表明,相对含量≥2.0的100个(SLS及SGS 40个,DEMs-up 60个)物质有92个存在显著相关性。SLS及SGS中29个关联物质及DEMs-up中19个物质,富集到15条重要通路,其主要涉及次生代谢产物的生物合成、氨基酸的生物合成及代谢、维生素的生物合成及代谢三大类通路。【结论】松露及松根所含有的代谢物间存在一定的网络关联;松露及松根中含有的一些物质,包括环磷酸腺苷(cAMP)、植物甾醇、3-吲哚乙酸等物质对子实体的发育具有重要的调控作用。研究结果为今后分析与子实体发育相关的潜在信号分子及探明云南松露与其共生松树的共生机制提供了理论依据,同时为筛选菌根苗及子实体的促生物质,为规模化人工培养松露等奠定了实践基础。     

墨兰‘达摩’原叶绿素酸酯氧化还原酶基因CsPORB功能的初步研究

为了解墨兰‘达摩’(Cymbidium sinense ‘Dharma’)的POR基因功能,从其嫩叶中克隆得到CsPORB基因。CsPORB的开放阅读框长度为1 200 bp,编码399个氨基酸,CsPORB分子量为43.13 kDa,理论等电点9.30;Cs PORB与其他物种的POR蛋白序列高度同源,在进化关系上较为保守;qRT-PCR表达分析表明,CsPORB在墨兰不同发育阶段和不同组织中的表达有明显差异,其集中于生长旺盛的嫩叶中表达。经高表达转基因表型验证,35S:CsPORB转拟南芥(Arabidopsis thaliana)植株中PORB及其下游叶绿素合成代谢酶活性显著提高,叶绿素含量增加,尤其在黑暗处理1周后,35S:CsPORB转基因植株仍表现持绿表型。因此,CsPORB基因可能在墨兰‘达摩’叶绿素合成代谢中发挥重要作用。     

Analysis of gene expression in the vegetative and fructification phases of the white truffle, Tuber borchii Vittad., by mRNA differential display

The mRNA differential display technique was used to compare mRNA populations from fruit body and mycelium of a white truffle species in the attempt to identify and clone differentially expressed genes. The differential expression of five out of 30 amplicons was confirmed. One fragment (Tbm 56) corresponded to a part of the ribosomal genes. Three cDNA fragments (Tbf 12, Tbf 20, Tbf 21) were expressed only in the fructification phase, while the other cDNA (Tbf 55) was expressed strongly in fruit body and also detectable in the mycelium. These clones correspond to part of the single-copy genes in the Tuber borchii Vittad. genome.     

Competition between Tuber melanosporum and other ectomycorrhizal fungi under two irrigation regimes

A glasshouse experiment was conducted to simulate the competition between artificially introduced Tuber melanosporum (Vitt.) and other symbionts, occurring on outplanted truffle-producing trees. Hazel (Corylus avellana L.) seedlings, previously inoculated with Tuber melanosporum, were rapidly infected with the competing truffle Tuber brumale (Vitt.), added to the soil as spores. Coexistence of both species on the root system was observed. Tuber melanosporum survived and continued to spread. Tuber brumale, which is naturally present in many truffle-orchard soils, protects the roots from other ectomycorrhizal symbionts. Although high water content is unfavourable for the development of T. melanosporum in the absence of other Tube species, Tuber brumale stimulates the development of T. melanosporum under these conditions.     

两种国兰C类花发育MADS基因的克隆与表达研究

该研究以蕙兰(Cymbidium faberi)和墨兰(Cymbidium sinense)为材料,利用RT-PCR对AGAMOUS (AG)基因进行克隆,并利用qRT-PCR进行组织表达.结果 表明:(1)获得3个AG基因均属于植物特有的C类MIKC型MADS-box基因,其中2个蕙兰AG基因命名为CfAG1(登录号...     

Experimental design to enhance the production of l-(+)-lactic acid from steam-exploded wood hydrolysate using Rhizopus oryzae in a mixed-acid fermentation

The fermentation of hemicellulosic hydrolysate from Pinus taeda chips, using the fungal culture Rhizopus oryzae, was carried out to produce l-(+)-lactic acid and to optimize and enhance the biological conversion of reducing sugar into l-(+)-lactic acid using the experimental design to evaluate the culture conditions. The first factorial design based on surface response with five factors (agitation level, substrate concentration, CaCO₃ concentration, C/N and C/P ratios) at low levels and one medium point was performed to optimize culture conditions. The second study tested two factors (substrate concentration and C/N ratio) at three levels. The statistical analysis of the data obtained from the factorial study showed that a C/N ratio of 35 and substrate concentration of 90 g/litre were the best conditions to produce l-(+)-lactic acid with R. oryzae on P. taeda hydrolysate, but in this case the statistical projection was not correct and the real optimized conditions were C/N ratio of 55 and substrate concentration of 75 g/litre of reducing sugar.     

华石斛化学成分研究

为了解华石斛(Dendrobium sinense)的化学成分,采用多种柱色谱技术从其全草乙醇提取液中分离纯化了10个化合物,经波谱分析分别鉴定为:鼓槌石斛素(1)、2′,4′-二羟基查尔酮(2)、2,5,7-三羟基-4-甲氧基-9,10-二氢菲(3)、4,7-二羟基-2,3-二甲氧基-9,10-二氢菲(4)、2,5-二羟基-3,4-二甲氧基-9,10-二氢菲(5)、2,7-二羟基-3,4,6-三甲氧基-9,10-二氢菲(6)、(E)松柏醛(7)、反式对羟基肉桂酸酯(8)、对羟基苯丙酸甲酯(9)和十二元内环酯(10)。所有化合物均为首次从华石斛中分离得到,其中化合物2、6、7和10对乙酰胆碱酯酶具有一定的抑制活性。     

Studies of macrophage immuno-modulating activity of polysaccharides isolated from Paecilomyces tenuipes

The objective of this study was to evaluate the immunomodulatory effects of the Paecilomyces sinensis polysaccharides (PtP) on the activity of macrophages and human monocytes. A water-soluble polysaccharide, with estimated molecular weight of 2.04 × 10⁴ Da, was isolated from P. sinensis. The results indicate that PtP can increase the activity of LDH and ACP in AMφ and PMφ of rats and human mononuclear cells, and enhance the pinocytic activity of macrophages and TNF-α production by human peripheral blood mononuclear cells (PBMC), suggesting that PtP had potent immunomodulatory properties and could be explored as a novel potential immunostimulants for the food and pharmaceutical purpose.     

Improvement of the ethanol productivity in a high gravity brewing at pilot plant scale

A 2³ full factorial design was used to study the influence of different experimental variables, namely wort gravity, fermentation temperature and nutrient supplementation, on ethanol productivity from high gravity wort fermentation by Saccharomyces cerevisiae (lager strain), under pilot plant conditions. The highest ethanol productivity (0.69 g l^–1 h^–1) was obtained at 20°P [°P is the weight of extract (sugar) equivalent to the weight of sucrose in a 100 g solution at 20°C], 15°C, with the addition of 0.8% (w/v) yeast extract, 24 mg l^–1 ergosterol and 0.24% (v/v) Tween 80.     

Investigations on the radiocaesium contamination of wild boar (Sus scrofa) meat in Rhineland-Palatinate: a stomach content analysis

To substantiate the pathways of radiocaesium contamination in wild boars in parts of Rhineland-Palatinate, we analysed radiocaesium-activityconcentration of 2,433 wild boars shot in an area covering 45,400 ha in the western part of the Palatinate Forest between January 2001 and February 2003. Also, for a fraction of 689 animals shot between May 2002 and February 2003, we collected their stomachs for the examination of content and Cs-activity concentration. Wild boar meat contamination followed a seasonal curve with maximum proportions exceeding accepted levels in the summer (21–26%) and minimum levels in winter (1–9.3%) indicating a higher consumption of a contaminating source during the vegetation period. The autumn decline is obviously attributed to the extensive consumption of low-contaminated beech nuts. An exact analysis of food composition in 18 stomachs with maximum Cs-activity concentrations [345–1,749 Bq/kg (fresh matter: fm)] and 18 with low Cs-activity concentrations (20–199 Bq/kg) was carried out in the summer of 2002. Deer truffles (Elaphomyces granulatus) were found in significantly higher proportions in stomachs with maximum contamination levels than in stomachs with lowcontamination levels. This fungus was found in the Palatinate Forest, by a trained dog, in average densities of 1 truffel/20 m² primarily in spruce stands, showing an average Cs-concentration of 6,030 Bq/kg (fm). On the basis of our findings we stress the hypothesis that deer truffles function as a main Cs-source for the wild boar in Rhineland-Palatinate.     

Cell wall polysaccharides are informative in Porphyra species taxonomy

As part of systematic studies of the genus Porphyrain New Zealand, constituent sugar analyses of cell wall polysaccharidesin situ in dry thalli were found to yield data that weretaxonomically informative. Variation in constituent sugar levels betweenspecieswas sufficient in some cases to be useful in species differentiation. Thereproductive state of thallus regions had a significant impact on the levels ofconstituent sugars, whereas storage of dried thalli for eight months had noeffect. Three epiphytic taxa currently classified as species ofPorphyra appear to be incorrectly placed within the genus,as their constituent sugars and the levels of these sugars differed markedlyfrom those of all other species examined.     

Bacillus fermentation of soybeans

Kinema fermentations of Indian and Canadian No. 1 soybeans by Bacillus sp. DK-W1 and by mixed cultures of Bacillus sp. DK-W1 and Enterococcus faecium DK-C1 were essentially identical. The viable cell count of Bacillus increased from an initial 10⁵ to 10¹⁰ c.f.u./g wet wt after 48 h incubation at 37°C. The pH of the fermentation dropped from an initial 6.9 to about 6.4 after 8 h and then rose to 8.6 after 32 h, with a coincident increase in proteolytic activity and ammonia concentration. The fermentations containing E. faecium and Bacillus exhibited a greater initial pH decline and a slightly retarded subseqent increase in pH compared with fermentations with Bacillus only. The presence of E. faecium had no detectable effects on growth of the Bacillus, proteolytic activity, ammonia production or the final pH of the fermentations.P.K. Sarkar was and P.E. Cook and J.D. Owens are with the Food Microbial Interactions Laboratory, Department of Food Science and Technology, University of Reading, Reading RG6 2AP, UK; P.K. Sarkar is now with the Microbiology Laboratory, Centre for Life Sciences, University of North Bengal, Siliguri 734430, India.     

Optimization of a protective medium for enhancing the viability of freeze-dried Lactobacillus delbrueckii subsp. bulgaricus based on response surface methodology

Response surface methodology (RSM) was used to optimize a protective medium for enhancing the cell viability of Lactobacillus delbrueckii subsp. bulgaricus LB14 during freeze-drying. Using a previous Plackett–Burman design, it was found that sucrose, glycerol, sorbitol and skim milk were the most effective freeze-drying protective agents for L. bulgaricus LB14. A full factorial central composite design was applied to determine the optimum levels of these four protective agents. The experimental data allowed the development of an empirical model (P<0.0001) describing the inter-relationships between the independent and dependent variables. By solving the regression equation, and analyzing the response surface contour and surface plots, the optimal concentrations of the agents were determined as: sucrose 66.40 g/L, glycerol 101.20 g/L, sorbitol 113.00 g/L, and skim milk 130.00 g/L. L. bulgaricus LB14 freeze-dried in this medium obtained a cell viability of up to 86.53%.     

Protection of a polysaccharide from Salvia miltiorrhiza, a Chinese medicinal herb, against immunological liver injury in mice

This study was designed to evaluate the hepatoprotective effects of S. miltiorrhiza polysaccharides (SMPS) in immunological liver injury induced by Bacille-Calmette-Guerin (BCG) and lipopolysaccharide (LPS) in mice. SMPS effectively improved the liver index, spleen index and thymus index, reduced the serum levels of alanine aminotransferase, aspartate aminotransferase and nitric oxide, and restored liver homogenate contents of tumor necrosis factor-alpha and interleukin-1beta. The histopathological analysis suggested that SMPS reduced the degree of liver injury. The results suggest that SMPS play a protective role against immunological liver injury, which may have important implications for our understanding on the immunoregulatory mechanisms of polysaccharides.