生防菌BJ1离子辐照突变高效菌株筛选及对黄瓜枯萎病的生防效果；Screening of Mutation High-Yielding Biocontrol Bacterium BJ1 by Ion Beam Irradiation and Effect of Controlling Fusarium oxysporum cucunerinum Disease

枯草芽孢杆菌BJ1是一种在真菌病害防治中发挥重要作用的生防因子,为进一步提高它的抑菌能力,获得生防效果更好的高效菌种,利用不同能量和剂量的12C6+对生防菌BJ1进行了离子辐照处理。研究结果表明:离子辐照生防菌BJ1的最适宜剂量为200~400 Gy,传能线密度(LET)为60 keV/μm;突变菌株的抑菌能力比BJ1提高了2%~21%;不仅防病效果比BJ1提高了17.48%,而且对植物具有更好的促生长作用。

Preparation, characterization and antifungal properties of 2-(alpha-arylamino phosphonate)-chitosan

In this paper, 20 kinds of different 2-(alpha-arylamino phosphonate)-chitosan (2-alpha-AAPCS) were prepared by different Schiff bases of chitosan (CS) reacted with di-alkyl phosphite in benzene solution. The structures of the derivatives (2-alpha-AAPCS) were characterized by FT-IR spectroscopy and elemental analysis. In addition, the antifungal activities of the derivatives against four kinds of fungi were evaluated in the experiment. The results indicated that all the prepared 2-alpha-AAPCS had a significant inhibiting effect on the investigated fungi when the derivatives concentration ranged from 50 to 500 mu g mL(-1). Furthermore, the antifungal activities of the derivatives increased with increasing the molecular weight and concentration. And the antifungal activities of the derivatives were affected by their dimensional effect and charge density. Besides, the rule and mechanism of the antifungal activities of them were discussed in this paper. (C) 2009 Elsevier B.V. All rights reserved.

毛壳菌产抗真菌活性物质菌株筛选及种间原生质体融合研究

毛壳菌属很多种类具有重要生防价值，其生防机理包括对植物病原真菌的重寄生作用、诱导植物产生抗病性、产生抗真菌活性的次生代谢产物等。迄今，学界对毛壳菌的研究主要集中在毛壳菌的生防机理，毛壳菌活性次生代谢产物的分离等方面。本研究致力于产抗生素的毛壳菌的种间原生质体融合，从产抗生素毛壳菌菌株的筛选开始，进而对产抗生素的角毛壳菌进行诱变选育，最终用产不同抗生素的角毛壳菌与球毛壳菌进行种间原生质体融合。主要有以下五方面研究结果。 1、毛壳菌抗真菌活性物质产生菌株的筛选：不同毛壳菌菌株发酵液采用琼脂扩散法对植物病原真菌进行抑菌活性试验，结果显示，菌株CH08和CH23的发酵液对芒果炭疽、苹果炭疽和马铃薯晚疫菌具有抑制作用。菌株CH16和CH17的发酵液对芒果炭疽菌、苹果炭疽菌有抑制作用。菌株CH21发酵液对辣椒炭疽菌和西瓜枯萎菌有抑制作用。经形态学研究，菌株CH08、CH16、CH17和CH23鉴定为球毛壳菌，菌株CH21鉴定为角毛壳菌。对角毛壳菌与球毛壳菌菌株发酵液抑菌谱比较，发现角毛壳菌与球毛壳菌发酵液具有明显不同的抑菌谱，表明角毛壳菌与球毛壳菌产生不同的抗真菌活性物质。 2、角毛壳菌（CH21）和球毛壳菌（CH08）原生质体制备和再生条件研究：考察了菌龄、酶浓度、稳渗剂及其浓度、酶解温度、酶解时间及再生培养基对原生质体制备和再生的影响。用菌龄为生长54 h的角毛壳菌菌丝，以0.06 M磷酸缓冲液（pH6.0）配制成含蜗牛酶15 mg/ml、溶壁酶10 mg/ml、蔗糖0.6 mol/L的酶解液，30℃酶解1.5 h，原生质体释放量2.02×107个/g；以PDA为再生培养基，0.7 mol/L的蔗糖再生稳渗剂，再生率可达51.45%。用菌龄为生长48 h的球毛壳菌菌丝，以0.06 M磷酸缓冲液（pH6.0）配制成含蜗牛酶15 mg/ml、溶壁酶10 mg/ml、蔗糖0.6 mol/L的酶解液，30℃酶解1 h，原生质体释放量达1.57×108个/g；以PDA为再生培养基，0.7 mol/L的蔗糖为再生稳渗剂，再生率可达41.48%。 3、角毛壳菌（CH21）原生质体紫外诱变选育：以CH21为出发菌株，制备原生质体进行紫外诱变，诱变条件为：15 w紫外灯，距离30 cm，照射90 s，致死率80%~85%。建立了诱变菌株初筛的双层平板筛选模型。经平板初筛和摇瓶复筛，获得一株突变菌株CH21-I-402，其发酵液抑菌活性较出发菌株提高18.3%。 4、抗性标记菌株的获得：菌株CH21-I-402和CH08抗生素药敏试验表明， CH21-I-402菌株对潮霉素有抗性、对G418（Geneticin）敏感，菌株CH08对潮霉素和G418都敏感。根癌农杆菌EHA105介导的新霉素磷酸转移酶基因转化球毛壳菌，经PCR检测，新霉素磷酸转移酶基因成功转化进菌株CH08-GR70，CH08-GR120。转化子对G418抗性提高3～4倍，对潮霉素仍然比较敏感。 5、以G418和潮霉素抗性为筛选标记的原生质体融合与融合菌株AFLP分析：制备角毛壳菌CH21-I-402和球毛壳菌CH08-GR70原生质体，以35％的PEG6000为助融剂进行原生质体融合，以65 μg/ml的潮霉素和60 μg/ml G418为抗性筛选标记，获得46个再生菌株。再生菌株连续传代5代后，再生菌株表现出多种形态类型。利用AFLP技术对再生菌株及亲本菌株基因组DNA分析表明，再生菌株PF1、PF26为融合菌株。抑菌活性测试表明，融合菌株PF26发酵液对芒果炭疽菌和苹果轮纹菌有强的抑制作用，且抑菌活性比亲本球毛壳菌明显提高。 Chaetomium spp. have great potentials as biocontrol agents against a range of plant pathogens on the basis of its mycoparasitism, induced plant disease resistance, production of antifungal metabolites, and so on. Previous researches on C. spp. mostly focused on the mechanisms of its biocontrol and the isolation of secondary metabolites. In this study, screening antifungal C. spp., mutation breeding of C. cupreum and interspecies protoplast fusion between C. cupreum and C. globosum were carried out, respectively. The corresponding results are as follows: Firstly, among more than 40 C. spp., the strains produced anti-fungal antibiotics were screened by agar diffusion experiments. Results showed that both CH08 and CH23 had inhibition against Colletotrichum gloeosporioides, Cladosporium fulvum, and Phytophthora infestans. Both CH16 and CH17 had inhibition against Colletotrichum gloeosporioides and Cladosporium fulvum. In addition, CH21 exhibited anti-fungal activity against Fusarium oxysporum f. sp niveum and Colletotrichum capsici. Furthermore, CH08, CH16, CH17 and CH23 were identified as C. globosum, CH21 was proved to be C. cupreum based on morphology. The comparison of the anti-fungal spectrum between C. cupreum and C. globosum, showed they could produce different antibiotics. Secondly, specified protocols for preparing and regenerating protoplasts from mycelia of C. cupreum CH21 and C. globosum CH08 were studied. The effects of the age mycelia, the concentration of enzyme, digestion temperature and time, kinds of osmotic stabilizer and regeneration medium on protoplasts preparation and regeneration were all optimized, respectively. In one protocol, with 15 mg/mL snailase, 10 mg/mL lywallzyme, 0.6 M sucrose, in 0.06 M phosphate buffer (pH6.0), and digested for 1.5 h at 30 ºC, 2.02×107 protoplasts from each gram mycelia were obtained from cultures of C. cupreum CH21 grown in potato dextrose broth (PDB) medium for 54 h. And when 0.7 M sucrose was used as osmotic stabilizer in the regeneration medium OPDA (potato dextrose agar with osmotic stabilize), the regeneration efficiency of protoplasts was 51.45%. In another protocol, with 15 mg/mL snailase, 10 mg/mL lywallzyme, 0.6 M sucrose, in 0.06 M phosphate buffer (pH6.0), and digested for 1 h at 30 ºC, 1.57×108 protoplasts from each gram mycelia were obtained from cultures of C. globosum CH08 grown in PDB for 48 h. And when 0.7 M sucrose was used as osmotic stabilizer in the regeneration medium OPDA, the regeneration efficiency of protoplasts was 41.48%. Thirdly, the mutagenesis conditions and secondary screening model of C. cupreum CH21 were explored. An 80% to 85% death rate could be achieved when the protoplasts of C. cupreum CH21 were irradiated by 15 w UV lamp from 30 cm distance for 90 s. In addition, the doublelayer plate’s method for the primary screening of high-producing antibiotics strains was established. A high yielding antibiotic mutant CH21-I-402 was obtained through the primary screening on plate and the secondary selection in Erlenmeyer flask, compared to the original CH21 strain, the antifungal activity of the mutant CH21-I-402 was increased by 18.3%. Fourth, the sensitivity to antibiotics of both C. cupreum CH21-I-402 and C. globusm CH08 was detected. Results showed C. cupreum CH21-I-402 was sensitive to G418 (Geneticin) (Gs) and resistant to Hygromycin B(Hr), and C. globusm CH08 was sensitive to both G418 (Geneticin) (Gs) and Hygromycin B(Hs). At the same time, neomycin phosphotransferase II (npt II) gene was transformed into C. globusm CH08(Gs, Hs) mediated by Agrobacterium tumefaciens EHA105, and the npt II gene was verified by polymerase chain reaction in resistance to G418 strains CH08-GR70 and CH08-GR120. The transformants still showed sensitive to Hygromycin B(Hs). Finally, a selection system for hybrids was set up by interspecies protoplast fusion between C. cupreum and C. globusm using dominant selective drug resistance markers. At first, protoplasts of C. cupreum CH21-I-402 (Hr, Gs) and C. globusm CH08-GR70 (Hs, Gr) were prepared, then the protoplasts were fused in the presence of 35% polyethylene glycol 6000 and regenerated on OPDA medium with 65 μg/ml Hygromycin B and 60μg/ml G418, at last 46 colonies with Hr and Gr were obtained. Even after 5 generations’ subculture, most of the colonies displayed significant difference in taxonomic characteristics with their parental strains. Regenerated strains PF1 and PF26 were confirmed as fusants by amplified fragment length polymorphisms analysis with the genomic DNA as the model. PF26 showed higher inhibitory activity against Colletotrichum gloeosporioides and Macrophoma kuwatsukai than that of the parental strain C. globusm.

杉木连栽致害真菌拮抗菌Bacillus subtilis3728的研究

杉木是我国重要的速生丰产树种，分布在北纬21°41′到33°41′，东经102°到122°的广大地区，杉木人工林面积约占我国人工林总面积的1/4，随着连栽代数的增加，土壤中毒和生产力下降程度日趋严重。 本论文以分离自与红树林、珍珠贝、海兔子、海绵、软珊瑚等与海洋动、植物共栖或共生存的106株海洋微生物(54株放线菌，52株细菌)为资源，以杉木连栽致害真菌尖孢镰刀菌萎蔫专化型(Fusarium oxysporum f.sp.vasinfectum)菌株SF2为靶菌，通过平板对峙试验和土壤原位定殖试验，筛选到一株分离自红树林木榄(Bruguiera gymnorrhizo)根际土壤的海洋细菌3728菌株；该菌对SF2具有很强抑菌活性，能够高密度在杉木根际土壤中定殖，对杉木幼苗的生长有一定的促进作用。采用传统的细菌学和分子生物学的鉴定方法对其进行了菌种鉴定，为枯草芽孢杆菌(Bacillus subtilis)。 通过对抗菌谱的研究，发现海洋细菌3728除了对杉木连栽主要致害真菌尖孢镰刀菌萎蔫专化型菌株SF2有很强的抑菌活性外，对大豆连作致害菌 (Penicillium purpurogenum)，棉花枯萎病菌(Fusarium oxysporum)，棉花立枯病菌(Rhizoctonia solani)，大豆根腐病菌(Fusarium solani)以及小麦赤霉病菌(Fusarium graminerum)等也有较强的抑制作用。室内模拟试验还表明，在土壤中接种海洋细菌3728后，能够明显增加土壤中氨化细菌和氨化真菌的数量，能够增加土壤中功能性微生物——纤维素分解细菌和纤维素分解真菌的数量和种类，增强了纤维素分解能力。再添加C/N比较低的白三叶草凋落物，土壤中氨化细菌、氨化真菌的数量继续增加，土壤纤维素分解能力更显著提高。这为进一步开展对杉木连栽障碍的生物调控试验，提供了一定的科学依据。

海洋细菌3512A对黄瓜枯萎病的防治及促进植株生长的效应

自南海柳珊瑚(Pacifigorgia sp.)中分离得到一株对黄瓜枯萎病菌尖孢镰刀菌黄瓜专化型(Fusarium oxysporum f.sp.cucumer-inum)有较强抑制作用的海洋枯草芽孢杆菌(Bacillus subtilis)3512A。经室内模拟试验表明,该菌株能够在灭菌土和有菌土中高密度定殖,促进黄瓜幼苗的生长。为探讨该菌株在室外对黄瓜枯萎病的生防作用及对黄瓜生长和产量的影响,进行了盆栽试验,结果表明,海洋细菌3512A能够有效地防治黄瓜枯萎病,促进黄瓜的生长,提高叶绿素含量,增加黄瓜的产量。

Synthesis of acyl thiourea derivatives of chitosan and their antimicrobial activities in vitro

Three different acyl thiourea derivatives of chitosan (CS) were synthesized and their structures were characterized by FT-IR spectroscopy and elemental analysis. The antimicrobial behaviors of CS and its derivatives against four species of bacteria (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Sarcina) and four crop-threatening pathogenic fungi (Alternaria solani, Fusarium oxysporum f. sp. vasinfectum, Colletotrichum gloeosporioides (Penz.) Saec, and Phyllisticta zingiberi) were investigated. The results indicated that the antimicrobial activities of the acyl thiourea derivatives are much better than that of the parent CS. The minimum value of MIC and MBC of the derivatives against E coli was 15.62 and 62.49 mu g/mL, respectively. All of the acyl thiourea derivatives had a significant inhibitory effect on the fungi in concentrations of 50 - 500 mu g/mL; the maximum inhibitory index was 66.67%. The antifungal activities of the chloracetyl thiourea derivatives of CS are noticeably higher than the acetyl and benzoyl thiourea derivatives. The degree of grafting of the acyl thiourea group in the derivatives was related to antifungal activity; higher substitution resulted in stronger antifungal activity. (c) 2007 Elsevier Ltd. All rights reserved.

中国南海深海沉积物中的微生物资源

由于采样条件和培养条件的限制，深海微生物研究的较少，因此目前海洋微生物资源的研究主要集中在近海和浅海。而深海独特的生态环境，使微生物形成了独特的代谢体系，成为新颖化合物的重要来源，具有很好的开发应用前景。本文首次较为系统的研究了深度为1758-3600m南海海底沉积物中深海微生物资源的分离和活性菌株的筛选情况，旨在为探索我国南海深海微生物资源提供一定的科学依据。 采用多种分离培养基从6个不同深度（1758、2620、3200、3500、3587和3600m）的南海深海沉积物样品中，分离到225株深海微生物，包括40株放线菌和185株细菌。以分离得到的225株深海微生物为研究对象，从产蛋白酶、抗真菌、杀虫三个方面进行活性菌株的筛选，研究南海深海沉积物中的微生物资源状况： （1）.将分离到的225株深海微生物，同时在10℃、28℃、45℃三个温度下进行产低温蛋白酶、中温蛋白酶、高温蛋白酶的筛选。初筛结果表明：这225株深海微生物大都有大小不同的产蛋白酶能力。10℃有产蛋白酶的有109株，28 ℃产蛋白酶的有160株，45℃产蛋白酶的有117株。筛选到一株在45℃下有较强产蛋白酶能力的菌株B1394，其酶活可达873U/ml，有一定的应用前景。通过形态观察、生理生化测定、16SrDNA序列测定，将B1394定名为枯草芽孢杆菌（Bacillus subtilis）。其粗酶液性质研究发现：最适酶活温度60℃，最适pH 8.0， 40℃、50℃和60℃热稳定性较好， Mn2+ 、Mg2+ 、Ca2+对该蛋白酶有激活作用，Hg2+ 、Fe3+ 、Cu2+ 、Zn2+ 、 Fe2+对其有抑制作用，苯甲基磺酰氟（PMSF）几乎完全抑制其活性，推断为丝氨酸蛋白酶。 （2）.对其中100株深海细菌和40株深海放线菌，以立枯丝核菌（ Rhizoctonia solani）和白色念珠菌（Candida albicans）为靶菌进行了抗真菌活性的筛选。初筛结果表明：分别有37株和35株深海细菌对立枯丝核菌和白色念珠菌有抑菌活性，分别占被检测细菌数目的37%和35%；有18株深海放线菌对立枯丝核菌有抑制作用，占被检测放线菌总数的45%。筛选到一株有较强抗真菌活性的深海放线菌SHA6，其发酵液对包括尖孢镰刀菌（Fusarium oxysporum）在内的10种植物病原菌有明显的抑制作用。对其发酵液的理化性质进行初步研究发现SHA6发酵液具有良好的热稳定性和酸碱稳定性, 对SHA6进行分子生物学鉴定后将其初步定名为为橙色单胞菌（Aurantimonas altamirensis）。 （3）.以卤虫为初步筛选模型，对其中的20株深海放线菌进行了杀虫方面的筛选，结果发现有5个深海放线菌菌株表现有较强的杀虫活性。其中深海放线菌SHA4发酵液的乙酸乙脂提取物杀卤虫的活性最强，在浓度为100μg/ml时杀卤虫活性为83%,而在浓度400ppm时，48h可以杀死38%的甜菜夜娥。对SHA4进行分子生物学鉴定后将其初步定为拟诺卡氏菌属（Nocardiopsis sp）。 总之，本论文阐明了我国南海深海沉积物中微生物资源状况的初步研究结果，为进一步开发利用我国南海深海微生物资源奠定了基础。

Study on Mitochondrial DNA Cytochrome b Gene of Chinese sea bass, Lateolabrax sp.

参考鳗鲡等鱼类线粒体 DNA序列进行了中国花鲈线粒体 DNA细胞色素 b基因片断的引物设计、PCR扩增及其序列测定。得到中国花鲈的碱基序列为 4 10 bp,其 A、T、G、C含量分别为 10 1bp(2 4 .6 3% )、112 bp(2 7.32 % )、72 bp(17.56 % )、12 5bp(30 .4 9% ) ,与鳗鲡等其他鱼类相同基因片断序列碱基含量相似。

Novel derivatives of chitosan and their antifungal activities in vitro

Three kinds of Schiff bases of carboxymethyl chitosan (CMCTS) were prepared, and their antifungal activities were assessed according to Jasso de Rodriguez's method. The results indicated that 2-(2-hydroxybenzylideneamino)-6-carboxymethylchitosan (HNCMCTS) and 2-(5-chloro-2-hydroxybenzylideneamino)-6-carboxymethylchitosan (HCCMCTS) had better inhibitory effects than those of chitosan or CMCTS against Fusarium oxysporium f. sp. vasinfectum, Alternaria solani, and Valsa mali. (c) 2005 Elsevier Ltd. All rights reserved.

大豆种子低温吸胀相关基因的分离与蛋白变化的研究

大豆 (Glycine max (L.) Meer.)是人们日常生活中不可缺少的食品，也是一种非常重要的油质、蛋白资源。目前根据大豆种子吸胀阶段对低温敏感性的不同，可将其划分成3种生态型：低温非敏感型、低温敏感型及中间型。对于低温非敏感型的种子来讲，4℃下吸胀24小时对其发芽率影响很小，而敏感型种子萌发率不超过5%。我国属于温带大陆性气候，大豆播种后由于温度波动而造成一部分种子不能萌发，最终导致减产甚至绝产的现象普遍存在。高产是育种工作的主要目标，提高逆境胁迫的适应能力是高产的前提和基础，所以从分子角度研究种子吸胀非常必要，一方面能够挖掘新的基因资源，另一方面为今后育种工作提供必要的理论依据。 本试验以此为立足点，低温吸胀非敏感型大豆品种 (Z22)为材料，利用cDNA-AFLP方法及蛋白质技术分离与低温吸胀相关的基因及蛋白，得到结果如下： 第一，本试验成功的分离出4个受低温诱导的基因，半定量RT-PCR方法进一步验证了这4个基因在种子吸胀24小时内受低温诱导。 第二，利用RACE方法成功的得到2个完整的全长基因，在NCBI数据库中查找后发现其中1个基因为新基因，命名为SCHI基因 (SCHI：Soybean chilling-induced gene)。SCHI全长为390bp，编码分子量大约为14.2KD的蛋白；另外一个基因是已知基因，其同源序列已经在其他的物种中得到分离。由于此基因与核糖体蛋白L34高度同源，所以把把这个基因命名为SOL34 (Soybean L34)。 第三，利用半定量RT-PCR方法对基因表达模型进行分析，结果表明：SCHI在种子低温吸胀18～24小时期间诱导表达量最高，而当种子低温吸胀24小时后转入常温下，其表达量在常温下18小时左右迅速下降；ABA (100μM)、PEG (30%，10000)及NaCl (250mM)能够诱导SCHI的表达，在诱导表达量上，ABA和PEG诱导效果最明显，而NaCl能够微弱的诱导此基因表达；对不同生态型的大豆品种而言，低温吸胀过程中，SCHI在非敏感型种子中的表达量高于敏感型种子，但非敏感型和中间型之间没有差别；另外，SCHI在大豆胚轴中是诱导型表达，在叶片和根尖中则是组成型表达。SOL34的表达在萌发前24小时内被低温诱导，但在不同生态型之间没有差别。SOL34在胚轴和根尖中受低温诱导，在叶片中是组成型表达。 第四，SCHI能够在原核生物中表达出相应蛋白，诱导表达蛋白的分子量在26-29KD，大约为理论值的2倍，说明在大肠杆菌中被表达的蛋白以2聚体形式存在。另外低温试验结果表明SCHI能够提高菌落忍耐短时间-20℃低温的能力。 第五，利用双元表达载体把SCHI转入拟南芥植株，经过低温、干旱和盐胁迫后，转基因植株的成活率均高于野生型植株。超表达SOL34的拟南芥植株降低了对低温的耐性；而抑制拟南芥中L34的表达反而提高了植株对低温的抗性。 第六，本试验利用蛋白质等有关试验检测了大豆种子低温吸胀时蛋白质发生的变化。从吸胀 (4℃和22℃下24h)后的大豆胚轴中成功鉴定出上调蛋白点25个，下调蛋白点15个。其中有参与能量代谢反应 (占10%，例如柠檬酸脱氢酶和苹果酸脱氢酶等)、细胞生长与分裂相关反应 (20%，例如LEA蛋白和种子成熟蛋白PM26)、胁迫反应 (10%，如乙醇脱氢酶)、种子宿命和贮藏蛋白 (20%，大豆球蛋白)等蛋白在此过程中发生了变化，暗示种子萌发前期低温吸胀过程中多种代谢发生变化。细胞生长变缓、能量代谢增强、胁迫代谢蛋白的高表达以及贮藏蛋白降解速度减慢等变化都有利于种子在吸胀过程中度过低温环境，为以后的生长作好准备。

条鳅亚科鱼类一新属新种

描述了云南省条鳅亚科鱼类一新属原条鳅属(Protonemacheilus, gen. nov.)和一新种长条原条鳅(P. longibectoralis, sp. nov.)。根据形态特征并结合区系间的相互关系, 探讨了属的分类地位。标本采于云南潞西的目康, 保存于中国科学院昆明动物研究所。图1表2参10

江汉平原晚更新世化石硅藻新种和新记录属种

在对江汉平原钻孔中属晚更新世地层的化石硅藻进行鉴定时,发现1个新种:Geissleria jianghanensis sp.nov.Li,2个中国新记录属:Geissleria和Aneumast us,6个中国新记录:Cymbella neuquina var.fastigata(Krasske)Krammer,Maidana et Villanueva,Cymbella perfossilis Krammer,Cymbella neocistula Krammer,Cym-bella neocistul

Morphological and genetic differences of Trypanosoma in some Chinese freshwater fishes: difficulties of species identification

Blood smears and purified trypanosome from freshwater fishes yellow catfish (Pseudobagras fulvidraco) and common carp (Cyprinus carpio) captured from Niushan Lake, Hubei Province were examined to determine whether all of their trypanosomes were Trypanosoma pseudobagri, a species of supposed host specificity and widespread existence across China. Trypanosomes occurred in 16/16 blood smears, and morphometric character analysis of trypanosomes from these smears showed that there were three morphospecies, Trypanosoma sp Carpio, T. sp Pseudobagri, and T. sp. 18S rDNA sequences of trypanosomes from 16 samples revealed three genetic groups among these fish trypanosomes. Group 1 was from C. carpio containing T. sp Carpio; groups 2 and 3 were from P. fulvidraco containing T. sp Pseudobagri and T. sp, respectively. The high similarity of morphometric characters and 18S rDNA sequences showed that T. sp Carpio and T. siniperca probably were the same species. T. sp Pseudobagri was the first occurrence in China. Sequence comparison showed that T. sp Pseudobagri sequence was most similar to that of clone Marv, whereas T. sp sequence differ from those of T. sp Carpio and T. sp Pseudobagri by 5.4 and 5.8%, respectively, and tentatively identified as T. pseudobagri. It was concluded that three species of trypanosomes, at least three genotypes occur in Niushan Lake fishes, and P. fulvidraco in this region appear to contain both types, although the identification of T. pseudobagri remains a problem.

两种高分子保水材料对盆栽甘蓝影响研究

采用盆栽试验,研究了两种高分子化合物聚丙烯酸钠(sodium polyacrylate,SP)与聚丙烯酰胺(Polyacrylamide,PAM)对甘蓝生长的影响。结果表明:在土壤中施入2/1000的两种高分子材料均能抑制土壤蒸发,砂土、粘土蒸发强度分别较对照降低35.5%、22.8%;甘蓝叶绿素受两种材料的影响不显著,受肥料影响较大;两种高分子材料施入土壤中增加了甘蓝产量、降低了根冠比,地上、地下生物量砂土较对照分别增加了61.1%、16.1%,粘土分别增加了55.2%、28.7%,根冠比砂土较对照平均降低了26.9%,粘土降低16%;PAM与SP使砂土容重较对照降低了13.9%,而粘土仅降低了4.1%;单施高分子处理水分利用效率平均较对照增加59.1%,与肥料混合使用时增加77.1%。总体来看,PAM与SP作用效果相近。