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1.
Three novel alkylphospholipid and four novel O-alkylglycerophospholipid derivatives of fludarabine (F-ara-AMP), known as a drug for the clinical treatment of chronic lymphocytic leukemia, were synthesized. The antiproliferative activity was determined in comparison to the parent nucleoside fludarabine in an immortalized but nontumorigenic human mammary epithelial cell line (H 184 A1N4), in two human breast tumor cell lines (MaTu and MCF7), and in two leukemic cell lines (HL 60 and Daudi). Fludarabine inhibited the growth of the leucemic cell lines very effectively. The breast tumor cell lines responded with much less sensitivity. The antiproliferative potency of the new compounds strongly depended on the chemical structure of the lipid component, and derivatives with a high effectiveness against one or both of the breast tumor cell lines were described.  相似文献   

2.
The reaction of perrhenate with 2-hydrazinopyrimidine in MeOH–HCl yields [ReCl31-NNC4H3N2H)(η2-HNNC4H3N2)] (1). The analogous reaction with Na2MoO4 yields [MoCl31-NNC4H3N2H)(η2-HNNHC4H3N2)] (1a). The reaction of 1 with pyrimidine-2-thiol and triethylamine produces [Re(η1-C4H3N2S)(η2-C4H3N2S)(η1-NNC4H3N2)(η2-HNNC4H3N2)] (2), while reaction of 1 with the Schiff base HSC6H4N=C(H)C6H4OH provides [Re(η3-SC6H4N=C(H)C6H4O)(η1-NNC4H3N2)(η2-HNNC4H3N2)]·0.6CH2Cl2 (3·0.6CH2Cl2). The analogous hydrazinopyridine complex of the Schiff base, [Re(η3-SC6H4N=C(H)C6H4O)(η1-NNC5H4N)(η2-HNNC5H4N)] (4), was also synthesized by reacting [ReCl31-NNC5H4NH)(η2-HNNC5H4N)] with HSC6H4N=C(H)C6H4OH. The crystal structures of 1–4 have been determined.  相似文献   

3.
Phospholipase A2 selectively hydrolyses the ester linkage at the sn-2 position of phospholipids forming lysocompounds. This bioconversion has importance in biotechnology since lysophospholipids are strong bioemulsifiers. The aim of the present work was to study the kinetic behaviour and properties of immobilized phospholipase A2 from bee venom adsorbed into an ion exchange support. The enzyme had high affinity for CM-Sephadex® support and the non-covalent interaction was optimum at pH 8. The activity of immobilized phospholipase A2 was comparatively evaluated with the soluble enzyme using a phospholipid/Triton X-100 mixed micelle as assay system. The immobilized enzyme showed high retention activity and excellent stability under storage. The activity of the immobilized system remained almost constant after several cycles of hydrolysis. Immobilized phospholipase A2 was less sensitive to pH changes compared to soluble form. The kinetic parameters obtained (Vmax 883.4 μmol mg−1 min−1 and a Km 12.9 mM for soluble form and Vmax = 306 μmol mg−1 min−1 and a Km = 3.9 for immobilized phospholipase A2) were in agreement with the immobilization effect. The results obtained with CM-Sephadex®-phospholipase A2 system give a good framework for the development of a continuous phospholipid bioconversion process.  相似文献   

4.
We describe herein the discovery and development of a series of 4-arylthieno[3,2-d]pyrimidines which are potent adenosine A2A receptor antagonists. These novel compounds show high degrees of selectivity against the human A1, A2B and A3 receptor sub-types. Moreover, a number of these compounds show promising activity in vivo, suggesting potential utility in the treatment of Parkinson’s disease.  相似文献   

5.
Six ascidian species from the Dutch North Sea coast were screened for cytotoxic activity. Freeze-dried biological material was extracted with solvents of different polarity followed by determination of the cytotoxicity. The most active extracts were further separated using different chromatographic techniques. The microculture tetrazolium (MTT) assay was used to determine the cytotoxicity against two human tumor cell lines: COLO320 (a colon adenocarcinoma) and GLC4 (a small cell lung carcinoma). The two cell lines were selected for their different response towards known cytostatics. GLC4 is sensitive and COLO320 is resistant to most of the known cytostatics. Three of the species tested yielded interesting fractions. From the in colonial Didemnum lahillei we have isolated a compound which is more active against the COLO320 cell line (IC50:33 μg ml−1) than the GLC4 (IC50:49 μg ml−1). The structure is currently elucidated. Another colonial species, Aplidium glabrum, yielded a very cytotoxic fraction, with an IC50 of 5 μg ml−1 against the COLO320 cell line. From our results it can be concluded that the North Sea could be another interesting source of new compounds with pharmaceutical potential.  相似文献   

6.
In whole mounts of seminiferous tubules of C3H/101 F1 hybrid mice, spermatogonia were counted in various stages of the epithelial cycle. Furthermore, the total number of Sertoli cells per testis was estimated using the disector method. Subsequently, estimates were made of the total numbers of the different spermatogonial cell populations per testis.

The results of the cell counts indicate that the undifferentiated spermatogonia are actively proliferating from stage XI until stage IV. Three divisions of the undifferentiated spermatogonia are needed to obtain the number of A1 plus undifferentiated spermatogonia produced each epithelial cycle. Around stage VIII almost two-thirds of the Apr and all of the Aal spermatogonia differentiate into A1 spermatogonia. It was estimated that there are 2.5 × 106 differentiating spermatogonia and 3.3 × 105 undifferentiated spermatogonia per testis. There are about 35,000 stem cells per testis, constituting about 0.03% of all germ cells in the testis. It is concluded that the undifferentiated spermatogonia, including the stem cells, actively proliferate during about 50% of the epithelial cycle.  相似文献   


7.
水氮组合对冬小麦干物质及氮素积累和产量的影响   总被引:2,自引:0,他引:2  
于2015—2017年小麦生长季在山东省泰安市农业科学研究院肥城试验基地进行田间试验,供试材料为‘泰山28',在150(A1)、300(A2)、450(A3)、600 m3·hm-2(A4)4个灌水量和90(B1)、135(B2)、180(B3)、225 kg·hm-2(B4)4个施氮水平下,研究水氮组合对小麦生长发育过程中干物质积累、氮素积累、水分消耗利用、光合特性、籽粒产量等的影响。结果表明: A3B3条件下各生育阶段的干物质积累量和氮素积累量,成熟期籽粒干物质和氮素积累量均为最大,花前花后营养器官生产储藏干物质及氮素向籽粒的运输量最高,且与其他水氮组合处理差异显著。各氮素处理下,60~200 cm土层土壤耗水量均为A3>A4>A2>A1;A3B3处理下的水分利用效率和氮素利用效率高于A3B4、A4B3和A4B4。A3B3处理显著提高了开花后7~28 d的旗叶净光合速率、气孔导度和蒸腾速率,有利于小麦进行光合作用合成碳水化合物。水氮组合效应显著影响籽粒产量和产量构成,且A3B3处理下小麦产量最高,达到9400 kg·hm-2。综上,450 m3·hm-2和180 kg·hm-2的水氮组合处理可以显著提高小麦干物质和氮素积累量,并促进干物质和氮素向籽粒运输,与高水肥处理相比,可以有效提高水分利用效率和氮素利用效率,有利于增强小麦旗叶的光合能力,产生更多的碳水化合物,增加籽粒产量。  相似文献   

8.
1,10-Phenanthroline-5,6-dione (C12H6N2O2 (1)) reacts with V(η6-mesitylene)2 and Ti(η6-toluene)2 affording coordination compounds of general formula M(O,O′---C12H6N2O2)3 (M=Ti (2); M=V (3)) which further react with TiCl4 or TiCp2(CO)2 yielding the tetrametallic species M(O,O′---C12H6N2O2---N,N′)3(M′Ln)3 (M=V, M′Ln=TiCl4 (4); M=Ti, M′Ln=TiCp2 (5); M=V, M′Ln=TiCp2 (6)). The complex salt [Fe(N,N′---C12H6N2O2)3][PF6]2 (7) has been obtained from iron(II) chloride tetrahydrate and 1 in the presence of NH4PF6. The reaction of 7 with TiCp2(CO)2 affords the tetrametallic derivative [Fe(N,N′---C12H6N2O2---O,O′)3(TiCp2)3][PF6]2 (8). TiCl2(THF)2 reacts with MCp2(O,O′---C12H6N2O2) to give MCp2(O,O′---C12H6N2O2---N,N′)TiCl2 (M=Ti (9); M=V (10)). By reaction of TiCp2(O,O′---C12H6N2O2---N,N′)TiCl2 (9) with C12H6N2O2, the bimetallic derivative TiCp2(O,O′---C12H6N2O2---N,N′)TiCl2(O,O′---C12H6N2O2) (11) has been prepared, which readily adds to TiCl4, to give the trimetallic titanium derivative TiCp2(O,O′---C12H6N2O2---N,N′)TiCl2(O,O′---C12H6N2O2---N,N′)TiCl4 (12). VCp2(O,O′---C12H6N2O2---N,N′)TiCl2 (10) reacts with the tris-chelate iron(II) cation 7 affording the heptametallic cationic complex [Fe(N,N′---C12H6N2O2---O,O′)TiCl2(N,N′---C12H6N2O2---O,O′)VCp2]3 +2 isolated as the hexafluorophosphate 13.  相似文献   

9.
利用田间小区试验,设计生物炭用量为0(B0)、1 kg·m-2(B1)、2 kg·m-2(B2)3个水平,氮肥用量为0(N0)、40 g·m-2(N1)、60 g·m-2(N2)3个水平, 即B0N0、B0N1、B0N2、B1N0、B1N1、B1N2、B2N0、B2N1和B2N2共9个处理,研究了生物炭与氮肥配施对牡丹叶片的氮素积累、叶片氮素向籽粒转移、籽粒蛋白氮、氨基酸和脂肪酸含量,以及籽粒产量和品质的影响.结果表明: 生物炭与氮肥配施增加了牡丹不同发育时期叶片中蛋白氮和非蛋白氮含量,以及叶片氮素向籽粒的转移量和籽粒氮素积累量.与B0N0处理相比,B1N1处理叶片氮素转移量和籽粒氮素积累量分别增加27.6%和27.1%;B1N1和B2N1处理牡丹籽粒百粒重和籽粒产量分别增加13.6%和16.4%,其中籽粒产量在B1N1、B1N2、B2N1和B2N2处理间差异不显著;B2N1和B1N2处理牡丹籽粒蛋白氮和总氨基酸含量较高,分别增加29.3%和36.2%.生物炭与氮肥配施增加了牡丹籽粒中总脂肪酸和不饱和脂肪酸的含量,其中,B2N1处理总脂肪酸含量较高, 比B0N0处理增加了17.4%.生物炭与氮肥配施能够增加牡丹叶片氮素积累量和叶片氮素向籽粒的转移量,增加籽粒产量,提高牡丹籽粒蛋白氮、氨基酸和脂肪酸的含量,其中以生物炭1 kg·m-2与氮肥40 g·m-2配施效果较好.  相似文献   

10.
植物在自然状态下释放负离子的能力很弱,施加脉冲电场可激发其释放能力。在密闭的玻璃箱中,研究紫背竹芋(Stromanthe sanguinea)、绒叶肖竹芋(Calathea zebrina)和朱顶红(Hippeastrum rutilum)在常态、脉冲电场和光照刺激下释放负离子的浓度,并观察叶片气孔特征,结果表明:(1)不同参数脉冲电场对植物释放负离子的能力影响不同,每种植物均具有高效释放负离子的最佳脉冲电场,紫背竹芋为A3B3C3(A3,U=1.5×104 V;B3,T=1.5 s;C3,?=65 ms);绒叶肖竹芋为A3B4C1(A3,U=1.5×104 V;B4,T=2.0 s;C1,?=5 ms);朱顶红为A4B4C1(A4,U=2.0×104 V;B4,T=2.0 s;C1,?=5 ms)。(2)植物体上所储存的电压越大,其释放负离子的能力越强。(3)脉冲电场作用时,植物释放负离子的能力与光照度呈正相关;无电场刺激时两者差异不显著(P0.05)。(4)植物释放负离子的能力与叶片气孔特征关系密切,脉冲电场作用下叶片气孔的开合度和气孔密度越大,其释放能力越强。  相似文献   

11.
Summary We have compared the ability of natural killer (NK) cells from two substrains of C3H mice that differ with respect to their susceptibility to the development of mammary adenocarcinomas to lyse fresh syngeneic mammary tumor cells. Single cell suspensions of mammary tumors from retired breeder females were used as targets in 22-h 51Cr-release cytotoxicity assays with syngeneic NK cells. Tumor cell suspensions were prepared by enzymatic digestion of finely minced tissue followed by centrifugation through a discontinuous Percoll gradient. Effector cells were prepared by passing spleen cells over nylon wool followed by centrifugation through Percoll fraction 7. Syngeneic NK cells had significant levels of lysis against 5/8 tumors studied. NK cells from low risk animals (C3Heb/FeJ) consistently demonstrated greater cytotoxicity against tumor cell preparations than did effectors from the high tumor substrain (C3H/OuJ). Study of cytocentrifuge preparations stained with Wright-Giemsa revealed that the two substrains were identical with respect to the number of azurophilic granules present in the cytoplasm of their NK cells. We have also shown that lymphokine-activated killer (LAK) cells can be generated from splenocytes in C3H mice. While LAK cells from both substrains were capable of lysing fresh syngeneic mammary tumor cells in vitro, LAK cells from the animals at high risk for the formation of mammary adenocarcinomas had greater cytotoxicity against tumor cell suspensions than LAK cells from the low tumor substrain.  相似文献   

12.
All stereoisomers of N-acyl-4,5-disubstituted oxazolidinone phospholipid analogs were synthesized by regio and stereoselective epoxide ring opening accompanied by introduction of an amino group. The (4R,5S)-derivative showed stronger inhibitory activity toward type II phospholipase A2 than the 4-substituted oxazolidinone phospholipid analog previously reported.  相似文献   

13.
Summary The two monoclonal antibodies (mAb), L6 (anti-carcinoma), and 1F5 [anti-(B-cell-lymphoma)], were chemically linked to the enzyme penicillin-V amidase (PVA), which hydrolyzes phenoxyacetamides, to explore the potential of using mAb-enzyme conjugates for the localizaton of chemotherapeutic drugs at tumor cells. The phenoxyacetamide derivatives of doxorubicin and melphalan were prepared, yielding the less toxic amides, doxorubicin-N-p-hydroxyphenoxyacetamide (DPO) and melphalan-N-p-hydroxyphenoxyacetamide (MelPO). These were hydrolyzed by PVA to doxorubicin and melphalan respectively.In vitro studies with the L6-positive lung carcinoma cell line, H2981, and the 1F5-positive B-cell lymphoma line, Daudi, showed that DPO was 80-fold less toxic to H2981 cells and 20-fold less toxic to Daudi cells than doxorubicin, and its toxicity was substantially increased when the H2981 cells were pretreated with L6-PVA or the Daudi cells were pretreated with 1F5-PVA. The cytotoxic effect was antigen-specific, since only the binding mAb-enzyme conjugate increased the cytotoxicity of the prodrug. MelPO was more than 1000-fold less toxic than melphalan to H2981 cells and more than 100-fold less toxic than melphalan to Daudi cells. Pretreatment with the mAb-PVA conjugates did not enhance the toxicity of MelPO in either cell line, because PVA hydrolyzes the phenoxyacetamide bond of MelPO too slowly to generate a toxic level of melphalan.  相似文献   

14.
为了探究秸秆还田滴灌灌水下限和秸秆还田量对温室番茄产量、品质和水分利用效率的影响,在温室内进行裂区试验。秸秆还田时间分别为1年(2018年)、2年(2017年)和3年(2016年),设置4个秸秆还田量(0、1.5×104、3×104、4.5×104 kg·hm-2)和4个灌水下限(50%θf、60%θf、70%θf、80%θf,θf为田间持水量),对土壤含水率、番茄产量和品质进行监测。采用方差分析、熵权法和TOPSIS法对番茄产量、品质和水分利用效率进行分析。结果表明: 番茄产量随灌水下限增大而增大,在灌水下限为80%θf时产量最大,秸秆还田第1、2和3年,最大平均产量分别为93.55、87.23和99.34 t·hm-2。水分利用效率和品质指标均随灌水下限的升高而降低。在秸秆还田第1年时,秸秆还田量为1.5×104 kg·hm-2时番茄平均产量达到最大值,为99.60 t·hm-2;在秸秆还田第2、3年时,秸秆还田量为4.5×104 kg·hm-2时番茄平均产量最大,分别为92.50和107.75 t·hm-2。番茄水分利用效率在秸秆还田第1、2年,秸秆还田量为1.5×104 kg·hm-2时达到最大;在秸秆还田第3年时,秸秆还田量为4.5×104 kg·hm-2达到最大。番茄的品质指标随秸秆还田年限和秸秆还田量增加表现出不同趋势。  相似文献   

15.
Two novel tetracopper(I) and tetrasilver(I) complexes [Cu4(atdz)6](ClO4)4·2CH3OH (1) and [Ag4(atdz)6](ClO4)4 (2), have been prepared using 2-amino-1,3,4-thiadiazole (atdz), and their crystal structures and properties have been determined. On each tetranuclear complex, two Cu or Ag atoms (M) are bridged by two atdz ligands to form a six-membered N2M2N2 framework. The two N2M2N2 frameworks are in parallel linked by another atdz ligand to provide the tetranuclear structure with a rectangular M4 core. The four Cu or Ag atoms possess a trigonal-square geometry. The two adjacent MM separations are (3.096(1) and 3.412(1) Å) and (3.316(2) and 3.658(2) Å) for 1 and 2, respectively. On both tetranuclear complexes there are two species of hydrogen bonds between the ClO4 − anions and the NH2 group of atdz ligands. It is proposed that the hydrogen bonds are related to the stabilization of the tetranuclear structure during the crystallization process.  相似文献   

16.
The Group IV phospholipase A2 family is comprised of six intracellular enzymes commonly called cytosolic phospholipase A2 (cPLA2) , cPLA2β, cPLA2γ, cPLA2δ, cPLA2ε and cPLA2ζ. They are most homologous to phospholipase A and phospholipase B/lysophospholipases of filamentous fungi particularly in regions containing conserved residues involved in catalysis. However, a number of other serine acylhydrolases (patatin, Group VI PLA2s, Pseudomonas aeruginosa ExoU and NTE) contain the Ser/Asp catalytic dyad characteristic of Group IV PLA2s, and recent structural analysis of patatin has confirmed its structural similarity to cPLA2. A characteristic of all these serine acylhydrolases is their ability to carry out multiple reactions to varying degrees (PLA2, PLA1, lysophospholipase and transacylase activities). cPLA2, the most extensively studied Group IV PLA2, is widely expressed in mammalian cells and mediates the production of functionally diverse lipid products in response to extracellular stimuli. It has PLA2 and lysophospholipase activities and is the only PLA2 that has specificity for phospholipid substrates containing arachidonic acid. Because of its role in initiating agonist-induced release of arachidonic acid for the production of eicosanoids, cPLA2 activation is important in regulating normal and pathological processes in a variety of tissues. Current information available about the biochemical properties and tissue distribution of other Group IV PLA2s suggests they may have distinct mechanisms of regulation and functional roles.  相似文献   

17.
A number of N,N′-bis(4-substituted phenyl)-1,7-diaza-12-crown-4 and N,N′-bis(4-substituted phenyl)-1, 10-diaza-18-crown-6 (where the substituents are OCH3, CH3, H, Cl, respectively) have been prepared by cyclization reaction of a ditosylate with the appropriately substituted diol. These new macrocyclic ligands have been characterized by means of elemental analysis, IR, 1H NMR and MS spectra. The crystal structures of N,N′-bis(4-chlorophenyl)-1,10-diaza-18-crown-6 (21) and its complex with barium thiocyanate Ba(SCN)2 (22) have been determined by single crystal X-ray diffraction. The crystallographic data are as follows: 21: C24H32Cl2N2O4, orthorhombic, P212121, A=4.852(1), B=11.989(2), C=41.231(8) Å, V=2398.7(8) Å3, Z=4; 22: C26H32Cl2N4O4S2Ba, monoclinic, P21/c, A=8.801(2), B=11.653(9), C=15.756(6) Å, ß=105.96(3)°, V=1553.7(14) Å3, Z=2. In the complex, the Ba atom is eight-coordinate (O(1), O(2), O(1)′, O(2)′, N(1), N(1)′, N(21), N(21)′) to form a distorted D6h geometry with the Ba atom at the center of crystallographic symmetry.  相似文献   

18.
19.
A series of pyrazolo[3,4-d]pyrimidine, pyrrolo[2,3-d]pyrimidine and 6-arylpurine adenosine A2A antagonists is described. Many examples were highly selective against the human A1 receptor sub-type and were active in an in vivo model of Parkinson’s disease.  相似文献   

20.
(S)- and (R)-3-dodecanoyl-4-phosphatidylcholinohydroxymethyl-2-oxazolidinone (1), which are cyclic analogues of the amide phospholipid 7, were synthesized. The inhibitory activities of these analogues toward phospholipase A2 were compared with that of the amide analogue 7.  相似文献   

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