起始生物量比对3种海洋微藻种间竞争的影响

为深入了解饵料微藻与赤潮微藻间的种间竞争关系,通过微藻共培养的方法,研究了起始生物量比(1:4、1:1和4:1)对3种海洋微藻(塔玛亚历山大藻、蛋白核小球藻和湛江等鞭金藻)两两之间种间竞争的影响,并对其作用机制进行了探讨。结果表明:①3种海洋微藻表现出种间竞争的相互抑制效应;②在与塔玛亚历山大藻(简称A)的种间竞争中,蛋白核小球藻(简称C)和湛江等鞭金藻(简称I)均在竞争中占优势,蛋白核小球藻随自身起始生物量比的提高,其竞争优势越加明显,湛江等鞭金藻在A:I=1:1时竞争优势最为明显;在蛋白核小球藻和湛江等鞭金藻的种间竞争中,当C:I=1:4时,湛江等鞭金藻在竞争中占优势,C:I=1:1时,初期湛江等鞭金藻占竞争优势,随蛋白核小球藻的迅速生长,后期蛋白核小球藻占竞争优势,C:I=4:1时,蛋白核小球藻占绝对竞争优势;③由种间竞争抑制参数比较得出:3种微藻的种间竞争强弱依次为蛋白核小球藻>湛江等鞭金藻>塔玛亚历山大藻。蛋白核小球藻和湛江等鞭金藻在起始比例C:I=1:1时,可共培养利用,在海产经济动物育苗中可对其进行适时采收投喂;两种饵料藻对塔玛亚历山大藻具有明显的抑制作用,可为开发利用饵料藻进行赤潮生物防控提供一定的科学依据。     

氮磷比对蛋白核小球藻和湛江等鞭金藻种间竞争的影响

为了了解饵料微藻的种间竞争关系,通过微藻共培养的方法,以NaNO3和KH2PO3作为氮源和磷源,研究了氮磷比对蛋白核小球藻(Chlorella pyrenoidosa)和湛江等鞭金藻(Isochrysis zhanjiangensis)种间竞争的影响。结果表明:在单养模式下,蛋白核小球藻生长适宜的N/P为4~22,N/P22时其生长受抑制,而湛江等鞭金藻生长受N/P影响不明显;共养模式可促进蛋白核小球藻的生长,而抑制湛江等鞭金藻的生长;蛋白核小球藻具有明显的竞争优势,且N/P为13和16时其种群竞争优势最明显;在蛋白核小球藻大规模生产性培养时可接入等生物量或少量湛江等鞭金藻,一方面利用共养模式提高蛋白核小球藻的产量,另一方面可根据养殖生产需要适时采收混合藻类饵料用于投喂。     

花群珊瑚对两种微藻的摄食

以花群珊瑚为材料,采用碳清除率测定、PCR分子营养标记和组织学观察的方法,研究花群珊瑚是否摄食亚心形扁藻和球等鞭金藻。结果表明: 花群珊瑚对球等鞭金藻的碳清除率显著高于亚心形扁藻,分别为0.44和0.11 pg·mL^-1·polyp^-1·h^-1。球等鞭金藻烯酰基载体蛋白还原酶基因片段作为分子标记在投喂组珊瑚组织中可扩增出目的片段。亚心形扁藻18S rRNA基因的引物在相应投喂组珊瑚组织中也可扩增出目的片段。组织学观察发现: 投喂组珊瑚水螅体内部隔膜较宽,隔膜与体壁的胃层都存在大量食物泡。亚心形扁藻投喂组在体壁胃层的食物泡中和口道沟处均发现未消化完全的亚心形扁藻。球等鞭金藻投喂组则在隔膜胃层和体壁胃层内的食物泡中发现所摄食金藻。因此,碳清除率、分子营养标记以及组织学观察均表明花群珊瑚对亚心形扁藻与球等鞭金藻存在摄食现象。     

营养强化时褶皱臂尾轮虫对饵料微藻的摄食

选取适宜浓度利用单种微藻和混合微藻对轮虫进行营养强化,采用实验生态学方法研究了轮虫滤水率和摄食率的动态变化.结果表明:微藻浓度、微藻种类和培养时间均对轮虫的滤水率和摄食率有显著影响;轮虫对几种单种微藻的滤水率和摄食率均随培养时间的延长而下降,在实验条件下,6h内轮虫对3种微藻的滤水率大小顺序为小球藻＞球等鞭金藻＞牟氏角毛藻,12h内轮虫对3种和,微藻的滤水率大小顺序则为球等鞭金藻＞小球藻＞牟氏角毛藻;轮虫在混合微藻中的选择顺序为球等鞭金藻＞小球藻＞牟氏角毛藻.     

固定化海洋微藻对污水中Ni2+的吸附

采用海藻酸钠包埋小球藻和叉鞭金藻,制得含藻细胞的固定化胶球,用其对Ni^2 进行生物吸附,研究了固定化小球藻和固定化叉鞭金藻对污水中Ni^2 的吸附率。结果表明：对于同一种固定化微藻,处于对数生长中期时对Ni^2 吸附效果较好,且吸附过程主要在前4h完成;Ni^2 浓度越大,吸附率越高;固定化微藻比悬浮态微藻吸附率高;在相同的实验条件下,固定化小球藻比固定化叉鞭金藻吸附率高。     

几种海洋浮游藻类的培养

海洋浮游藻类的培养,是第二次世界大战后才开展研究的。据报道,用于牡蛎、蛤、贻贝、扇贝、鲍鱼、海参、对虾及鱼类等幼体饵料的种类主要有:单鞭金藻(Monochrysis lutheri),等鞭金藻(Isochrysis galbana),小金藻(Chromulina pleiades),扁藻(Platymonas sp.),盐藻(Dunaliella sp.),小球藻(Chlorella sp.),     

不同饵料对魁蚶稚贝生长和存活的影响

在温度23.5～24.0 ℃和盐度29.5～30.0条件下,研究了球等鞭金藻、小球藻、牟氏角毛藻和新月菱形藻4种单细胞藻类单独及组合投喂24 d后对魁蚶稚贝生长与存活的影响.结果表明: 不同饵料投喂条件下,稚贝存活率均在95%以上,不同处理组间差异不显著.单一饵料投喂组中,球等鞭金藻组的稚贝生长最快,小球藻组的稚贝生长最慢.组合投喂组中,球等鞭金藻与其他3种单胞藻混合(1∶1)投喂组稚贝壳长及特定生长率均优于其他组,其中与小球藻混合投喂的效果最好,稚贝壳长和壳高的特定生长率分别为5.6%·d^-1和6.4 %·d^-1.研究结果可为魁蚶人工苗种培育技术的优化提供参考依据.
     

温度、盐度和食物条件对西藏拟溞摄食强度的影响

报道了不同温度、盐度和饵料条件下西藏拟溞的摄食强度、西藏拟溞对不同饵料生物蛋白核小球藻(Chlorellapyrenoidesa)、牟氏角毛藻(Chaetoceros muelleri)、湛江等鞭金藻(Isochrysis zhanjiangensis)、亚心形扁藻(Platymonas subcordiformis)、盐藻(Dunaliella salina)、新月拟菱形藻(Nitzschiella closterium)的选择性以及摄食节律。结果表明,在适温范围(2 20℃)内,西藏拟溞的滤水率、摄食率随着温度的升高而增加,14 16℃为西藏拟溞的适宜温度。在盐度20时,西藏拟溞的摄食率最高,幼、成溞对等鞭金藻的摄食率分别为1.88 ng C/(ind.h)和3.46 ng C/(ind.h)。西藏拟溞对角毛藻的滤水率和摄食率均随着龄期增加而增加,而对等鞭金藻呈相反趋势,但二者的日粮均随体长增大而减小。幼、成溞的滤水率和摄食率随食物密度变化的趋势基本一致,均是在盐藻密度为1×106 ind./L时均最高,分别为0.194、0.221 mL/(ind.h)和0.030μgC/(ind.h)和0.034μgC/(ind.h)。幼溞对6种藻的食物选择性为角毛藻小球藻盐藻扁藻金藻拟菱形藻;成溞为扁藻角毛藻盐藻金藻小球藻拟菱形藻。幼溞、成溞均对角毛藻和盐藻的选择性较好。西藏拟溞的幼溞和成溞对牟氏角毛藻的摄食有相同的节律,在15:00 17:00和01:00 03:00时有两个摄食高峰,在09:00 11:00和23:00 01:00有两个低谷。     

蛋白核小球藻脂溶性化合物的抑菌活性及成分分析

利用纸片法对蛋白核小球藻（Chlorella pyrenoidosa Chick.）脂溶性化合物的粗脂以及经硅胶柱层析分离后的不同组分进行了抑菌实验。结果表明,蛋白核小球藻的粗脂有极强的抑菌活性,其石油醚洗脱组分占总脂的63.9％,抑菌活性最弱;乙醇洗脱级分占总脂的32.2％,抑菌活性最强;苯洗脱组分只占总脂的3.9％,对玉米大斑病菌（Helminthosporium turcicum Pass）有极强的抑制活性。各洗脱组分及粗脂对革兰氏阴性菌均我抑制活性。成分分析结果表明,石油醚洗脱组分以烷烃类化合物为主,其中1-十九烯经烃含量最高;苯洗脱组分以6,10,14-三甲基-2-十五酮、十六碳酮和2-十一烷酮这3种酮类化合物为主;而乙醇洗脱组分含有大量的脂肪酸,其中γ-亚麻酸含量最高（56.673％）。蛋白核小球藻脂溶怀化合物的抑菌活性是其各种化学成分相互综合作用的结果。     

棕鞭藻对蛋白核小球藻的摄食及其营养策略

在研究稻草秸秆对蛋白核小球藻(Chlorella pyrenoidosa)的化感作用时,偶然发现一株对蛋白核小球藻具有强烈的取食作用的鞭毛虫,能有效抑制小球藻的大量繁殖。经形态学观察,该种鞭毛虫具有2片淡黄色色素体,片状、周生;虫体呈球形、椭圆形或卵形,能变形,具2根不等长的鞭毛,从细胞顶部伸出;长鞭毛约为虫体的1.5倍,短鞭毛约为虫体的0.5倍;对蛋白核小球藻的吞噬能力极强,每个虫体可以吞噬3~4个小球藻,虫体大小因吞噬物的多少变化较大。初步确定这种鞭毛虫为棕鞭藻(Ochromonas sp.)。在SE、稻草以及麦粒3种培养基中的种群生长表明,这种棕鞭藻在麦粒培养基最易培养,生长速度最快。结果表明,这种棕鞭藻为混合营养类型,但以吞噬营养为主。     

Synthesis of a new class of 2-anilino substituted nicotinyl arylsulfonylhydrazides as potential anticancer and antibacterial agents

A series of N'-1-[2-anilino-3-pyridyl]carbonyl-1-benzenesulfonohydrazide derivatives (7a-i) was synthesized and five of them were selected by the National Cancer Institute (NCI) and evaluated for their in vitro anticancer activity. Three of the investigated compounds 7d, 7f and 7g exhibited significant anticancer activity in the primary assay and further tested against a panel of 60 human tumour cell lines. Compound 7g showed 50% growth inhibitory activity in leukaemia, melanoma, lung cancer, colon cancer, renal cancer and breast cancer cells with GI(50) value of 3.2-9.6 microM. The synthesized compounds (7a-i) were also evaluated for their antibacterial activity against various Gram-positive and Gram-negative strains of bacteria. Most of these compounds showed better inhibitory activity in comparison to the standard drugs.     

The oxidative mechanism of action of ortho-quinone inhibitors of protein-tyrosine phosphatase alpha is mediated by hydrogen peroxide

Here, we report the identification and characterization of five ortho-quinone inhibitors of PTPalpha. We observed that the potency of these compounds in biochemical assays was markedly enhanced by the presence of DTT. A kinetic analysis suggested that they were functioning as irreversible inhibitors and that the inhibition was targeted to the catalytic site of PTPalpha. The inhibition observed by these compounds was sensitive to superoxide dismutase and catalase, suggesting that reactive oxygen species may be mediators of their inhibition. We observed that in the presence of DTT, these compounds would produce up to 2.5mM hydrogen peroxide (H(2)O(2)). The levels of H(2)O(2) produced were sufficient to completely inactivate PTPalpha. In contrast, without a reducing agent the compounds did not generate H(2)O(2) and showed little activity towards PTPalpha. In addition, these compounds inhibited PTPalpha-dependent cell spreading in NIH 3T3 cells at concentrations that were similar to their activity in biochemical assays. The biological implications of these results are discussed as they support growing evidence that H(2)O(2) is a key regulator of PTPs.     

Bioactive compounds from Caulerpa racemosa as a potent larvicidal and antibacterial agent

Marine algae are rich sources ofbioactive compounds capable of harboring secondary metabolites which are structurally and biologically active. In our study, the methanolic extract of marine algae Caulerpa racemosa （green algae） was employed to determine the antibacterial and larvicidal activity. The antibacterial activity showed effective inhibition against five pathogenic bacteria. A significant zone size of 16 mm was observed for Pseudomonas aeruginosa. The methanolic extract of Caulerpa racemosa showed effective larvicidal activity against Culex tritaeniorhynchus and the histopathological studies revealed the rupture in mid gut of larvae. The bioactive compounds in the crude extract were further identified as 2-（-3-bromo-1-adamantyl） acetic acid methyl ester and Chola-5, 22- dien-3-ol by GC-MS. Hence the bioactive compounds obtained from the methanolic extracts could be used for the bactericidal and larvicidal activity which will overcome the harmful impact of synthetic insecticide on environment.     

Synthesis of new thieno[2,3-b]pyridine derivatives as pim-1 inhibitors

Three series of 5-bromo-thieno[2,3-b]pyridines bearing amide or benzoyl groups at position 2 were prepared as pim-1 inhibitors. All the prepared compounds were tested for their pim-1 enzyme inhibitory activity. Two compounds (3c and 5b) showed moderate pim-1 inhibitory activity with IC₅₀ of 35.7 and 12.71?μM, respectively. Three other compounds (3d, 3g and 6d) showed poor pim-1 inhibition. The most active compounds were tested for their cytotoxic activity on five cell lines [MCF7, HEPG2, HCT116, A549 and PC3]. Compound 3g was the most potent cytotoxic agent on almost all the cell lines tested.     

Purification, properties, and isozyme pattern of galactose-1-phosphate uridyl transferase from calf liver.

Galactose-1-phosphate uridyl transferase was purified approximately 2000-fold from calf liver with a yield of 15%. The purification procedure involved ammonium sulfate fractionation, calcium phosphate-gel adsorption, and chromatography on DEAE-cellulose, hydroxylapatite, and Sephadex columns. The purified product demonstrated five protein bands on polyacrylamide-gel electrophoresis. Each band had transferase activity as five peaks of activity were observed on preparative polyacrylamide-gel electrophoresis. Galactose-1-phosphate uridyl transferase showed no requirement for divalent metals for activity. In contrast, it was inhibited by Mg²⁺ and other divalent metals. The purified enzyme but not the crude preparation was stimulated by sulfhydryl compounds. The enzyme was completely inhibited by low concentrations of p-hydroxymercuribenzoate.     

Popolohuanones G – I,Dimeric Sesquiterpene Quinones with IL‐6 Inhibitory Activity from the Marine Sponge Dactylospongia elegans

Chemical investigation of the marine sponge Dactylospongia elegans, collected from the South China Sea, afforded three new dimeric sesquiterpene quinones, popolohuanones G – I ( 1 – 3 ), together with two known analogs, popolohuanones B ( 4 ) and C ( 5 ). The new structures were determined by HR‐ESI‐MS and 1D‐ and 2D‐NMR analyses. All the five compounds showed no cytotoxic activity against five human cancer cell lines, while popolohuanone H ( 2 ) showed potent inhibitory activity against IL‐6, an inflammatory cytokine, at the concentration of 10 μm .     

Biologically active tetralones from New Caledonian Zygogynum spp

Bioassay guided purification of the ethyl acetate extracts of the bark and leaves of five New Caledonian Zygogynum species (Winteraceae) led to the isolation and characterization of four phenyl-3-tetralones (3,4-dihydronaphthalen-1(2H)-one). Their structures were determined by various NMR techniques and chemical studies. The absolute configuration of the compounds was established by circular dichroism. The compounds showed binding affinity for peroxisome proliferator-activated receptor-γ (PPAR-γ) and significant inhibitory activity against KB cancer cell line.     

Exploring the thiazole scaffold for the identification of new agents for the treatment of fluconazole resistant Candida

Cyclohexyliden- and 2-methylcyclohexyliden-hydrazo-4-arylthiazoles were synthesized and tested as antifungal agents. All compounds exhibited minimal inhibitory concentration (MIC) values comparable with those of fluconazole (FLC). Moreover, some compounds showed fungicidal activity at low concentration. Worth noting five out of nine compounds were active towards Candida albicans 25 FLC resistant isolated from clinical specimens. The cellular toxicity was evaluated and none of the compounds is toxic at the MIC. On the basis of our data we can conclude that these derivatives are promising agents for the treatment of resistant C. albicans.     

Synthesis of 3'-deoxy-3'-C-methyl nucleoside derivatives

2',3'-Dideoxy-3'-C-methyl nucleosides bearing the five naturally occurring nucleic acid bases were synthesized. Additionally, the 3'-deoxy-3'-C-methyl nucleoside analogues bearing 5-aminoimidazole-4-carboxamide as well as 1,2,4-triazole-3-carboxamide moieties were prepared. The synthesis of the corresponding 2',3'-dideoxy-3'-C-methyl triazole derivative was also accomplished. The dideoxynucleoside derivatives were prepared by radical deoxygenation from their 3'-deoxy-3'-C-methyl parent ribonucleosides. When evaluated for their antiviral activity in cell culture experiments, none of these compounds showed any significant antiviral activity.     

Triazolopyridazine derivatives: Synthesis,cytotoxic evaluation,c-Met kinase activity and molecular docking

Novel series of some triazolo[4,3-b]pyridazine derivatives were designed and synthesized. All the newly synthesized compounds were evaluated for their cytotoxic activity at 10⁻⁵ M concentration towards 60 cancer cell lines according to USA NCI protocol. Most of the synthesized compounds showed good activity against SR (leukemia) cell panel. The most active compounds, 2f and 4a were subjected for further evaluation at a five dose level screening and their efficacy for c-Met kinase inhibition was determined in vitro. Binding mode of these derivatives was explored via molecular docking.