H-13木霉对水稻硝酸还原酶及氮、磷、钾的影响*

采用离子束对哈茨木霉进行注入并筛选出H-13菌株,该菌株发酵液含有对水稻生长有显著促进作用的物质;经对喷施该菌株发酵液后的水稻硝酸还原酶(NR)活力及其N、P和K含量的测定,发现该菌株发酵液促进水稻生长与提高NR活力、增强对N、P和K的吸收有关。     

H-13木霉对水稻硝酸还原酶及氮、磷、钾的影响

采用离子束对哈茨木霉进行注入并筛选出H-13菌株,该菌株发酵液含有对水稻生长有显促进作用的物质;经对喷施该菌株发酵液后的水稻硝酸还原酶(NR)活力及其N、P和K含量的测定,发现该菌株发酵液促进水稻生长与提高NR活力、增强对N、P和K的吸收有关。     

离子注入哈茨木霉筛选高产促植物生长物质菌株的研究

用 N+注入哈茨木霉所获得的突变型的发酵液浇灌水稻种子 ,结果发现 :5× 10 - 6、5× 10 - 5、2× 10 - 4木霉突变株发酵稀释液处理的种子幼苗长势优于对照组和木霉原种组。其 5 0倍、15 0倍木霉发酵稀释液浇灌的种子幼苗过氧化物酶同工酶与对照和原种相比均出现了新的谱带 A- 3、C- 3带。各突变株 5 0倍发酵稀释液和原种发酵液浇灌的水稻幼苗过氧化物酶同工酶出现了 B- 3带。而四种浓度的木霉发酵稀释液处理的水稻幼苗 ,其酯酶同工酶与对照组和原种组相比 ,无明显差异     

哈茨木霉对水稻过氧化物酶及多酚氧化酶活性的影响*

哈茨木霉不仅对病原微生物有拮抗作用,而且能够诱导植物产生抗病性。采用酶动力学扫描及垂直板凝胶电泳技术,对水稻喷施木霉发酵液后,测定多酚氧化酶(PPO)、过氧化物酶(POD)活性和同工酶带图谱的动态变化。与对照组相比,哈茨木霉不仅能够提高PPO和POD酶的活力,而且还能诱导产生新的同工酶谱带,但不同浓度发酵液对诱导合成的酶作用不同。稀释50倍的发酵液对POD活力有较大的阳性效应。高浓度的发酵液对PPO活性有先抑制后出现提高的趋势,表明了该发酵液对PPO活性调节的程序性。     

哈茨木霉SKD-ZX-1的鉴定、发酵及其生防效果

哈茨木霉作为一类重要的生防菌,对蔬菜病害致病菌具有拮抗作用。为确定分离的哈茨木霉SKD-ZX-1的生防效果,利用气质联用技术对菌株的发酵液进行测定和分析,利用宏基因组测序方法分析该菌株对番茄根腐烂病土壤中的细菌菌群的影响,并且采用平板对峙培养法对该菌株与链格孢菌和茄链格孢菌进行了拮抗实验。结果显示,哈茨木霉SKD-ZX-1发酵液中有邻苯二甲酸二异丁酯、邻苯二甲酸二丁酯和邻苯二甲酸二(2-乙基己基)酯等抑菌成分,并且其发酵液增大了土壤中细菌菌群的种类,与对照组相比,实验组肠杆菌属提高了46%,而假单胞菌属和梭菌属降低了5.28%和36.1%。该哈茨木霉对两种病原菌的抑制率均达到100%,拮抗系数达Ⅰ级。研究表明哈茨木霉SKD-ZX-1对链格孢菌和茄链格孢菌具有显著的抑制作用,其发酵液具有一定的抑菌效果。     

哈茨木霉与绿色木霉对杉木种子萌发和幼苗生长的影响

以杉木种子为材料,研究不同浓度(0.003、0.03、0.3、3、30、300 mg·L^-1)哈茨木霉和绿色木霉溶液对杉木种子萌发和幼苗生长的影响.结果表明: 各浓度木霉溶液处理对杉木种子萌发和幼苗生长均有一定的促进作用,其促进效果随着处理浓度的增加均呈先升后降的趋势.与对照相比,0.03 mg·L^-1哈茨木霉和绿色木霉处理对提高杉木种子的发芽率、发芽势、发芽指数、活力指数、根长、苗高和鲜质量效果最佳,分别提高了57.6%、125.0%、51.0%、209.2%、114.3%、16.1%、24.6%和42.7%、76.7%、43.9%、185.4%、113.8%、8.6%、22.6%;0.3 mg·L^-1哈茨木霉和绿色木霉显著提高杉木幼苗超氧化物歧化酶和过氧化物酶活性,分别增加了157.6%、179.9%和127.5%、116.2%,而丙二醛含量降低了86.1%和72.4%. 0.03～0.3 mg·L^-1浓度的哈茨木霉和绿色木霉不仅能显著促进杉木种子的萌发和幼苗生长,而且能够提高其抗氧化酶活性,增强杉木幼苗的抗逆性.     

5株生防真菌对孢囊线虫的杀线活性测定

为了丰富防治线虫的真菌资源,测定了实验室分离保存的5株生防真菌粉红粘帚霉JGZ、淡紫紫孢菌Y2和BL2、哈茨木霉菌L4和球孢白僵菌BJ对甜菜孢囊线虫、大豆孢囊线虫和禾谷孢囊线虫的杀线虫活性。结果表明,淡紫紫孢菌Y2和哈茨木霉菌L4的孢囊寄生率为100%,随着作用时间增长,孢囊壁消解破裂。5株真菌发酵液随着稀释倍数的增加,线虫的校正死亡率降低。哈茨木霉菌L4的5倍发酵稀释液对甜菜孢囊线虫、大豆孢囊线虫和禾谷孢囊线虫的校正死亡率分别为96.75%、95.95%和96.35%;淡紫紫孢菌Y2的5倍发酵稀释液对甜菜孢囊线虫、大豆孢囊线虫和禾谷孢囊线虫的校正死亡率分别为97.37%、95.74%和97.77%,两者差异不显著。盆栽试验结果表明,哈茨木霉菌L4和淡紫紫孢菌Y2发酵液作用大豆孢囊线虫30 d,孢囊减退率分别为43.67%和41.87%,根长和茎粗显著高于其他处理,哈茨木霉菌L4处理地上鲜重和地下鲜重显著高于其他处理。结合孢囊寄生率、发酵液杀线活性、孢囊减退率和促生作用综合评价,哈茨木霉菌L4生防效果最好。     

草果叶斑病防治初步研究

从发病的草果叶片上分离得到草果叶斑病病原菌,进行药剂筛选试验,把不同处理的哈茨木霉(Tri-choderma harzimum)菌株和病原菌对峙培养,结果表明:春雷霉素400倍药液下病菌菌丝无法生长,金歌1 500倍、多菌灵800倍、易保1000倍、春雷霉素500倍药液对病原菌菌丝生长抑制率在61%以上;不同处理的哈茨木霉菌株对草果叶斑病病原菌均有抑制效果,且药物诱变和紫外线诱变的突变菌株比野生型菌株抑菌效果显著。     

微生物菌剂对秸秆降解及秸秆中微生物变化规律的影响

为明确不同微生物菌剂对秸秆降解率及秸秆降解过程中秸秆周围微生物变化规律的影响，在温室大棚内进行不同微生物菌剂降解秸秆试验。以玉米秸秆为基质，设玉米秸秆（对照组）、玉米秸秆+哈茨木霉（Trichoderma harzianum）（处理1）、玉米秸秆+哈茨木霉+地衣芽胞杆菌(Bacillus licheniformis)（处理2）三个处理。研究结果显示，单独用哈茨木霉处理可显著提高秸秆降解率，前期作用尤其明显；在秸秆降解的前30 d，秸秆降解率与秸秆中可培养真菌、细菌、放线菌呈显著正相关。不同微生物菌剂对秸秆中可培养微生物数量变化有显著影响，单独接种哈茨木霉后，秸秆中可培养真菌、细菌、放线菌数在前30 d显著高于对照组和混合菌剂处理，不同处理可培养活菌数均在90～120 d达到峰值，然后开始下降。研究结果表明，不同微生物菌剂对秸秆降解有显著影响，单独用哈茨木霉处理可显著提高秸秆降解率；不同处理对秸秆中可培养真菌、细菌、放线菌的影响有显著差异。可为秸秆降解与微生物相关性研究提供参考。     

哈茨木霉发酵液中肽类物质对豇豆土著根瘤菌竞争结瘤的影响

通过树脂吸附、离子交换、薄层层析、高效液相色谱系统以及紫外、质谱等分离、纯化和鉴别的方法,从哈茨木霉T2-16菌株发酵液中分离得到一种对豆科作物生长具促进作用的肽类物质。用该肽类物质对豇豆土著根瘤菌进行处理后,用AFLP技术研究了该物质对供试根瘤菌遗传稳定性和在土壤中竞争结瘤能力的影响。结果表明,传代次数和培养温度(28℃~36℃范围)对供试根瘤菌的遗传性状无明显影响,其AFLP指纹未发生明显变化;但经木霉肽类代谢产物处理后,根瘤菌竞争结瘤能力得到提高,为对照根瘤菌的1.53倍。     

Characterization of Metabolites in IntactStreptomyces citricolorCulture Supernatants Using High-Resolution Nuclear Magnetic Resonance and Directly Coupled High-Pressure Liquid Chromatography–Nuclear Magnetic Resonance Spectroscopy

A novel NMR spectroscopic approach to the direct biochemical characterization of bacterial culture broths is presented. A variety of one- and two-dimensional 1H NMR spectroscopic methods were used to characterize low-molecular-weight organic components of broth supernatants from cultures of Streptomyces citricolor. By applying 1H NMR spectroscopy to analyze whole, untreated culture supernatants, it was possible to identify and monitor simultaneously a range of media substrates and excreted metabolites. Identified metabolites include 2-phenylethylamine, trehalose, succinate, acetate, uridine, and aristeromycin, a secondary metabolite with antibiotic properties. Directly coupled HPLC-NMR spectroscopy was also applied to the analysis of broth supernatants for the first time, to aid spectral assignments, especially where signals were extensively overlapped in the 1H NMR spectra of the whole broth mixtures. Two-dimensional NMR methods such as 1H-1H correlation spectroscopy, 1H-13C heteronuclear single quantum correlation, and 1H-13C heteronuclear multiple bond correlation aided the structure elucidation and peak assignments of individual components in the mixtures by providing information on 1H-1H coupling networks and 13C chemical shifts. This work shows that high-resolution NMR spectroscopic methods provide a rapid and efficient means of investigating microbial metabolism directly without invasive or destructive sample pretreatment.     

水溶性红曲黄色素的表征及其稳定性

以含硫化合物还原红曲色素,红斑素和红曲红素分子中的环羰基还原成羟基,得到水溶性红白曲黄色素.以 UV-Vis、IR和(?)H-~(13)CNMR对其结构进行了表征.该色素的吸光度随pH增大而略呈上升趋势,避光可明显提高其稳定性.除Mg~(2 )在pH9下使其溶液产生沉淀外,Sn~(2 )、Ca~(2 )、Fe~(3 )和AI~(3 )均不影响其稳定性.不同pH和温度下加热实验结果表明,酸性条件对其热稳定性影响较大.     

Characterization of two peptides isolated from the venom of social wasp Chartergellus communis (Hymenoptera: Vespidae): Influence of multiple alanine residues and C-terminal amidation on biological effects

Chatergellus communis is a wasp species endemic to the neotropical region and its venom constituents have never been described. In this study, two peptides from C. communis venom, denominated Communis and Communis-AAAA, were chemically and biologically characterized. In respect to the chemical characterization, the following amino acid sequences and molecular masses were identified:Communis: Ile-Asn-Trp-Lys-Ala-Ile-Leu-Gly-Lys-Ile-Gly-Lys-COOH (1340.9 Da)Communis-AAAA: Ile-Asn-Trp-Lys-Ala-Ile-Leu-Gly-Lys-Ile-Gly-Lys-Ala-Ala-Ala-Ala-Val-Xle-NH₂ (1836.3 Da).Furthermore, their biological effects were compared, accounting for the differences in structural characteristics between the two peptides. To this end, three biological assays were performed in order to evaluate the hyperalgesic, edematogenic and hemolytic effects of these molecules. Communis-AAAA, unlike Communis, showed a potent hemolytic activity with EC₅₀ = 142.6 μM. Moreover, the highest dose of Communis-AAAA (2nmol/animal) induced hyperalgesia in mice. On the other hand, Communis (10nmol/animal) was able to induce edema but did not present hemolytic or hyperalgesic activity. Although both peptides have similarities in linear structures, we demonstrated the distinct biological effects of Communis and Communis-AAAA. This is the first study with Chartegellus communis venom, and both Communis and Communis-AAAA are unpublished peptides.     

Enzymatic production of highly soluble myricitrin glycosides using beta-galactosidase

Myricitrin, a botanical flavonol glycoside, could be a useful ingredient of functional foods, cosmetics, and medicines because of its high anti-oxidative activity. However, due to its insolubility in water, it has a limited range of use. To improve this solubility, we glycosylated myricitrin by an enzymatic transglycosylate reaction. Myricitrin was galactosylated by beta-galactosidase from Bacillus circulans using lactose as a sugar donor. The reaction product was 480 times more soluble than myricitrin. Four myricitrin galactosides were isolated from the reaction products by column chromatography, and their molecular structures were identified by using ESI-MS, 1H-NMR, 13C-NMR, 1H-1H COSY, 1H-13C HMQC and 1H-13C HMBC analysis. The solubility of these four myricitrin galactosides was more than 3.9 x 10(3) fold that of myricitrin, and each had similar anti-oxidative activity to that of myricitrin.     

Absolute configuration of fusarone, a new azaphilone from the endophytic fungus Fusarium sp. isolated from Melia azedarach, and of related azaphilones

A new azaphilone derivative, named fusarone (1), has been isolated from the ethyl acetate soluble extract of the fermentation broth of an endophytic fungus, Fusarium sp. LN-12, isolated from the leaves of Melia azedarach Linn. The structure of the new compound was established on the basis of extensive spectroscopic analysis, including 1D-NMR and 2D-NMR ((1) H-(1)H COSY, TOCSY, HSQC, HMBC, and NOESY) experiments. The absolute configurations of fusarone (1) and of a second related azaphilone were determined by means of electronic circular dichroism spectroscopy and optical rotation calculations.     

硅对菜心炭疽病发生、菜薹形成及硅吸收沉积的影响

采用不同浓度硅(Si)对菜心进行处理, 研究了Si对菜心炭疽病发生、菜薹形成及Si吸收沉积的影响.结果表明：Si对菜心炭疽病的发生有明显的调控作用,并存在基因型差异;感病品种2.5 mmol·L^-1和抗病品种0.5 mmol·L^-1Si处理对炭疽病菌的抗性最强,病情指数最低,菜薹产量最高.Si对菜心品质也有明显影响,不同浓度Si处理可促进感病品种的叶绿素、粗纤维、Vc的合成,并诱导可溶性糖的生成,且叶绿素、粗纤维含量随Si处理浓度的提高而增加;抗病品种的叶绿素含量随Si处理浓度的增加明显增加,而Vc含量下降,Si对抗病品种的粗纤维、可溶性糖含量影响不显著;Si对两个品种菜薹的粗蛋白和可溶性蛋白质含量影响均不显著.施Si明显提高了菜心叶片Si的积累,且叶片的Si含量随着Si处理浓度的增加而显著提高;叶片组织沉积的Si粒大小不一,Si在叶片表皮组织呈不均匀分布.表明Si在菜心叶片中的积累可提高植株的抗病能力,但其积累量与植株的抗病能力不呈直线相关关系.     

Inhibition of an allospecific T cell hybridoma by soluble class I proteins and peptides: estimation of the affinity of a T cell receptor for MHC

To investigate the molecular basis of the interaction between the T cell receptor and the MHC class I antigen in an allogeneic response, a soluble counterpart of the murine class I molecule, H-2Kb, was genetically engineered. Cells secreting this soluble molecule, H-2Kb/Q10b, inhibited stimulation of an H-2Kb-reactive T cell hybridoma by cells transfected with H-2Kbm10, a weak stimulus, but not by H-2Kb- or H-2Kbm6-transfected cells. Soluble purified H-2Kb/Q10b protein also blocked T cell stimulation. In addition, a peptide from the wild-type H-2Kb molecule spanning the region of the bm10 mutation specifically inhibited activation of the T cell hybridoma by H-2Kbm10 cells, thus suggesting that amino acid residues 163-174 of H-2Kb define a region important for T cell receptor binding. An estimate for the Kd of the T cell receptor for soluble H-2Kb/Q10b was 10(-7) M, while the Kd for soluble peptide 163-174 was 10(-4) M.     

Role for protein kinase C in the modulation of glomerular PGE2 production by angiotensin II

Angiotensin II increased PGE2 release from superfused glomeruli, and stimulated labeled inositol phosphate production. 12-O-Tetradecanoyl phorbol -13-acetate (TPA, 10(-7) M), which stimulates protein kinase C activity in soluble fractions of glomerular homogenates, suppressed angiotensin II actions on inositol phosphate production and PGE2. By contrast, 4a phorbol 12,13 di-decanoate and phorbol had no effect on protein kinase C activity or angiotensin II induced increases in inositol phosphate or PGE2. 1-(5-Isoquinolinyl)-2-methylpiperazine (H-7), which inhibits protein kinase C activity in soluble fractions of glomerular homogenates, prevented TPA induced suppression of angiotensin II actions on inositol phosphate production and PGE2. Moreover H-7 prolonged the time course of angiotensin II induced inositol phosphate production and enhanced angiotensin II actions on glomerular PGE2 production. The results support a role for inositol phospholipid hydrolysis through the phospholipase C pathway in the mediation of angiotensin II actions on PGE2 in glomeruli and are consistent with negative modulation of these actions by protein kinase C.     

Synthesis of a water-soluble analog of 6-methyl-3-N-alkyl catechol labeled with carbon 13: NMR approach to the reactivity of poison ivy/oak sensitizers toward proteins.

A 13-C labeled water soluble derivative of alkylcatechol was synthesized and reacted with human serum albumin in phosphate buffer at pH 7.4 in air to allow a slow oxidation of the catechol into orthoquinone. The formation of several adducts was evidenced by a combination of 13C and 1H-13C correlation NMR. Although some adducts could result from a classical o-quinone formation - Michael type addition, our results suggest that a second pathway, involving a direct reaction of a carbon centered radical with proteins could be an important mechanism in the formation of modified proteins.     

NMR signal assignments of amide protons in the alpha-helical domains of staphylococcal nuclease

We report complete assignments of the amide proton signals in the three long dNN connectivity sequences observed in the NOESY spectrum of deuteriated staphylococcal nuclease (Nase) complexed with thymidine 3',5'-bisphosphate (pdTp) and Ca2+, Mr 18K. The assignments are made by comparing NOESY spectra with 1H-15N and 1H-13C heteronuclear multiple-quantum shift correlation (HMQC) spectra of Nase samples containing 15N- and 13C-labeled amino acids. The assignments show that the residues which are linked by the dNN connectivity sequences are located in three alpha-helical domains of Nase. Our results indicate that by combining NOESY and HMQC spectra of appropriately labeled samples it should be possible to delineate and study alpha-helical domains in soluble proteins having molecular weights that are greater than 18K.