首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Entomological Review - The type and other extensive material of Coprophilus (Zonyptilus) pennifer (Motschulsky, 1845) and some of its synonyms was examined. Coprophilus (Zonyptilus) marginalis...  相似文献   

2.
Secoisolariciresinol diglucosides (SDGs) (S,S)-SDG-1 (major isomer in flaxseed) and (R,R)-SDG-2 (minor isomer in flaxseed) were synthesized from vanillin via secoisolariciresinol (6) and glucosyl donor 7 through a concise route that involved chromatographic separation of diastereomeric diglucoside derivatives (S,S)-8 and (R,R)-9. Synthetic (S,S)-SDG-1 and (R,R)-SDG-2 exhibited potent antioxidant properties (EC50 = 292.17 ± 27.71 μM and 331.94 ± 21.21 μM, respectively), which compared well with that of natural (S,S)-SDG-1 (EC50 = 275.24 ± 13.15 μM). These values are significantly lower than those of ascorbic acid (EC50 = 1129.32 ± 88.79 μM) and α-tocopherol (EC50 = 944.62 ± 148.00 μM). Compounds (S,S)-SDG-1 and (R,R)-SDG-2 also demonstrated powerful scavenging activities against hydroxyl [natural (S,S)-SDG-1: 3.68 ± 0.27; synthetic (S,S)-SDG-1: 2.09 ± 0.16; synthetic (R,R)-SDG-2: 1.96 ± 0.27], peroxyl [natural (S,S)-SDG-1: 2.55 ± 0.11; synthetic (S,S)-SDG-1: 2.20 ± 0.10; synthetic (R,R)-SDG-2: 3.03 ± 0.04] and DPPH [natural (S,S)-SDG-1: EC50 = 83.94 ± 2.80 μM; synthetic (S,S)-SDG-1: EC50 = 157.54 ± 21.30 μM; synthetic (R,R)-SDG-2: EC50 = 123.63 ± 8.67 μM] radicals. These results confirm previous studies with naturally occurring (S,S)-SDG-1 and establish both (S,S)-SDG-1 and (R,R)-SDG-2 as potent antioxidants and free radical scavengers for potential in vivo use.  相似文献   

3.
In order to investigate the relationship existing between the electronic structures of collagen and its biochemical functions in vivo, the semiempirical CNDO/2 SCF MO calculations were carried out on several model polymers of collagen, (Gly-Pro)n, (Gly-Hyp)n, (Ala-Pro)n, (Ala-Hyp)n, (Gly-Pro-Gly)n, (Gly-Hyp-Gly)n, (Gly-Pro-Pro)n and (Gly-Pro-Hyp)n. Geometries of the skeleton of these polymers were assumed to be the same as those of poly(l-proline) I (cis) and II (trans) and the calculations were performed only on infinite polymers in a single chain. The results show that the cis form is always more stable than the trans form for all the polymers treated. This energy difference between the cis and trans forms depends, for example, on the kind of amino acid residue, Gly or Ala, but this could not be seen in the Pro or Hyp residue. The flexibility or mobility of the collagen structure was explained using the energy difference between the cis and trans forms of the polymers, i.e. the cis-trans conversion of the collagen was discussed in connection with the energy difference. The reason why the collagen has the constitution of (Gly-Pro-Hyp)n is briefly discussed.  相似文献   

4.
王小蕾  张润杰 《生态科学》2009,28(5):471-476
对瓜实蝇Bactrocera (Tetradacus) minax (Enderlein)、桔小实蝇Bactrocera (Bactrocera) dorsalis (Hendel)和桔大实蝇Bactrocera (Zeugodacus) cucurbitae (Coquillett)的形态学、生物学、生态学等方面进行了比较和分析,包括三种实蝇在国内外的分布情况,对寄主选择的差异,各种虫态的形态特征,发育历期和生活史,并对它们的危害状况和防治方法分别作了介绍,可为3种实蝇的鉴定和防治提供参考.  相似文献   

5.
The complexes cis-diamminebis-cholylglycinate (O,O') [Pt(II) C(52)H(90)N(4)O(12)Pt, for convenience referred to as Bamet-R1] and cis-diamminebis-ursodeoxycholate (O,O') Pt(II) (C(48)H(84)N(2)O(8)Pt, Bamet-UD2) were prepared. The structural integrity of the compounds was confirmed by elemental analysis, FT-IR, NMR, FAB-MS, and UV spectroscopies. The kinetic study of both compounds was accomplished by combining the conductivity measurement and those of the analysis of the electronic spectra in aqueous solution for NaCl concentrations of 4 mM (similar to cytoplasmatic concentration), 150 mM (similar to plasmatic concentration), and 500 mM. In water, the compound Bamet-R1 showed a half-life, t(1/2), of 3.0 h. This compound forms the chelate species through loss of a ligand, and the other one acts as a bidentate ligand. Ring opening in the presence of chloride ion was produced with a k(Cl)()-of 0.25 M(-)(1) h(-)(1). The half-life of Bamet-UD2 in aqueous solution was 3.2 h. However, since this species is not able to chelate and has a lower degree of solubility in the presence of chloride ion, its kinetic behavior was very different from that of the other compound. We consider this to be of great interest with regards to its cytostatic activity. All kinetic measurements were performed under pseudo-first-order conditions, and a pseudo-first-order behavior was found. The antitumoral effect of Bamet-UD2 on several cell lines derived from rat hepatoma, human hepatoma, mouse leukemia, and human colon carcinoma was found to be, in general, similar to that of cisplatin, but higher than that observed for Bamet-R1.  相似文献   

6.
Three new coordination polymers [M(Pht)(1-MeIm)2]n (where M=Cu (1), Zn (2), Co (3); Pht2−=dianion of o-phthalic acid; 1-MeIm=1-methylimidazole) and two compounds [M(1-MeIm)6](HPht)2 · 2H2O (M=Co (4), Ni (5)) have been synthesized and characterized by X-ray crystallography. The structures of 1-3 (2 is isostructural to 3) consist of [M(1-MeIm)2] building units connected by 1,6-bridging phthalate ions to form infinite chains. In complex 1, each copper(II) center adopts a square coordination mode of N2O2 type by two O atoms from different phthalate ions and two N atoms of 1-MeIm, whereas in 3 two independent metal atoms are tetrahedrally (N2O2) coordinated to a pair of Pht ligands and a pair of 1-MeIm molecules. There are only van der Waals interactions between the chains in 1, while the three-dimensional network in 3 is assembled by C-H?O contacts. In contrast to polymers 1-3 the structures of 4 and 5 (complexes are also isostructural) are made up of the [M(1-MeIm)6]2+ cation, two hydrogen phthalate anions (HPht) and two H2O solvate molecules. The coordination around each metal(II) atom is octahedral with six nitrogen atoms of 1-MeIm. Extended hydrogen bonding networks embracing the solvate water molecules and a phthalate residue as well as the weak C-H?O interactions stabilize the three-dimensional structures. Magnetic studies clearly show that the magnetic ions do not interact with each other. Furthermore, in compound 4 we have another example of a highly anisotropic Co2+ ion with a rhombic g-tensor and large zero-field-splitting. The complexes were also characterized by IR and 1H NMR spectroscopy, thermogravimetric analysis, and all data are discussed in the terms of known structures.  相似文献   

7.
The West African river crab, Potamonautes (Platypotamonautes) ecorssei (Marchand, 1902) is reported to occur for the first time in Ghana and for only the second time in Nigeria. Its geographical range is extended south to include the Volta river basin in Ghana, and east to northwest Nigeria, a distance of some 1200 km.  相似文献   

8.
Until now, the knowledge on pholcid spermatozoa is based on two species, Pholcus phalangioides and, incompletely, Holocnemus pluchei. To complete this knowledge and to reveal more potential phylogenetic characters, we have investigated sperm ultrastructure and spermiogenesis of H. pluchei. We found that the sperm cells of this species are clearly different from those of P. phalangioides with respect to: (1) the lack of specialization in the cylindrical acrosomal vacuole; (2) a nuclear canal which is located in the periphery and not in the center of the nucleus; (3) a more prominent postcentriolar elongation of the nucleus; (4) the presence of "inner microtubules" in the implantation fossa in early and mid-spermatids; (5) the absence of a helical band of nuclear material; (6) the proximal centriole which is not prolonged; (7) the types of secretion in the seminal fluid (only two types in H. pluchei). Similarities in the spermatozoa of both species concern: (1) a large implantation fossa which contains large amounts of glycogen in mature spermatozoa; (2) absence of a centriolar adjunct; (3) an axonemal basis located in the posterior part of the implantation fossa; (4) the formation of the so-called cleistospermia in the vas deferens. Our results strongly support systematic relationships within Pholcidae placing these two species in different subgroups.  相似文献   

9.
Disolution of Co(bzt)2(NCS)2 (bzt = benzo 1,3- thiazole) in dimethyl formamide (dmf) produces Co(bzt)2(NCS)2(dmf)2. The stoichionmetry of the complex has been established by a combination of chemical (C, H, N) and thermal analysis. The comlex has an octahedral structure with pairs of ligands in trans configuration as well as a CoN4O2 coordination sphere with CoN distances of 2.185(2) Å (bzt); 2.082(2) Å (NCS) and CoN(dmf) of 2.118(2) Å. The infrared and electronic absorption spectra are consistent with this arrangement.  相似文献   

10.
A series of eight novel diamminetetrakis(carboxylato)platinum(IV) complexes was synthesized and characterized by multinuclear (1) H-, (13) C-, (15) N-, and (195) Pt-NMR spectroscopy. Their antiproliferative potency was evaluated in three human cancer cell lines representing ovarian (CH1), lung (A549), and colon carcinoma (SW480). In cisplatin-sensitive CH1 cancer cells, cytotoxicity was found in the low micromolar range, whereas, in inherently cisplatin-resistant A549 and SW480 cells, the activity was very low or negligible. Astonishingly, raise in lipophilicity of the complexes, as found in the case of cisplatin analogs, did not result in a significant enhancement of the cytotoxic effect.  相似文献   

11.
Gildenkov  M. Yu. 《Entomological Review》2020,100(7):1009-1019
Entomological Review - The type material of several synonyms of Coprophilus (Zonyptilus) pennifer (Motschulsky, 1845) is revised. Both Coprophilus (Zonyptilus) striatipennis (Eppelsheim, 1894) and...  相似文献   

12.
Abstract. The freshwater ostracod Tonnacypris glacialis (Sars, 1890) is reported from the European Pleistocene for the first time. The historical allocation of the species is discussed, and the species composition and characteristics of Tonnacypris Diebel & Pietrzeniuk (1975) and its phylozoogeography are considered. The significance of T. glacialis is reviewed, particularly from the viewpoint of the possible implications of parthenogenesis (and occasional-male production) for the Quaternary history of the genus, and for the use of the species in palaeoenvironmental reconstruction. It is suggested that the Pleistocene fossil occurrence of T. glacialis in modern temperature latitudes is a robust indicator of mean summer temperatures of 6°C.  相似文献   

13.
14.
The complexes (Tpms)VCl2(DMF) (1), and (Tpms)VOCl(DMF) (2), have been synthesized and characterized. Complex 2 has also been structurally characterized via X-ray diffractometry. The vanadium(IV) center possesses a square pyramidal/distorted octahedral geometry with a facially coordinating Tpms ligand in a κ3-N,N,O coordination mode. The complex is the first structurally characterized example of a vanadium(IV) complex with Tpms. Complex 2 shows catalytic activity towards oxidation of 3,5-di-tert-butyl catechol and also exhibits phosphatase inhibition characteristics on alkaline phosphatase. Tpms = trispyrazolylmethanesulfonate; DMF = N,N-dimethylformamide.  相似文献   

15.
16.
Despite their structural similarity, [Pt(dien)(1-MeC-N3)](2+) (1), [Pd(dien)(1-MeC-N3)](2+) (2), and [Pt(NH(3))(3)(1-MeC-N3)](2+) (3) (with dien=diethylenetriamine and 1-MeC=neutral 1-methylcytosine) behave in part markedly different at strongly alkaline pH (12-13) and at room temperature. While 1 and 2, yet not 3 show linkage isomerization from N3 to N4, deamination of the cytosine nucleobase to 1-methyluracilate occurs with 1 and 3, yet not with 2. Pathways leading to N3,N4-diplatinated 1-MeC(-) complexes (1-MeC(-)=1-methylcytosine, deprotonated at exocyclic amino group N4) have been studied at high pH by starting from 1 and 3, respectively, and adding (dien)Pt(II). It appears that initial migration of the metal entity from N3 to N4, followed by binding of the second metal to the available N3 site, is favored over sequential coordination to N3 and then N4. X-ray crystal data of 1-3 density functional theory (DFT) calculations, and NMR ((1)H, (195)Pt) data are presented.  相似文献   

17.
A number of 1,2-bis(diphenylphosphino)ethane monomeric platinum(II) and palladium(II) complexes have been synthesized in light of their potential antitumor activity. The metal center is coordinated with a number of carboxylate anions in the cis-configuration. These complexes have been characterized by elemental analysis, conductivity measurement, and various spectroscopic techniques [IR and 195Pt NMR]. In vivo screening tests for activity of these complexes were performed against the L1210/0 murine leukemia cancer model, but none displayed a significant level of antitumor activity.  相似文献   

18.
19.
Two pseudopolymorphs, solvates, of [Cu(2)(II)(niflumate)(4)(H(2)O)(2)] of unknown structure were obtained following solution of [Cu(2)(II)(niflumate)(4)(H(2)O)(2)] in N,N-dimethylacetamide (DMA) or N,N-dimethylformamide (DMF). Low-temperature crystal structures obtained for these solvates revealed that they were ternary aqua DMA and DMF solvates: [Cu(2)(II)(niflumate)(4)(H(2)O)(2)].4DMA and [Cu(2)(II)(niflumate)(4)(H(2)O)(2)].4DMF. Intermolecular hydrogen bonding interactions account for the formation of these stable DMA and DMF solvates. These pseudopolymorphs contain a centrosymmetric binuclear center with Cu-Cu bond distances ranging from 2.6439(7) to 2.6452(9) A; the coordination sphere of Cu(II) is characterized by one long Cu-O (water) bond length of 2.128(3)-2.135(3) A and four short Cu-O (carboxylate) bonds of 1.949(3)-1.977(3) A. Crystal parameters for the DMA pseudopolymorph: a=10.372(1), b=19.625(2), c=17.967(2) A, beta=97.40(1) degrees , V=3626.8(6) A(3); monoclinic system; space group: P2(1)/a and for the DMF pseudopolymorph: a=10.125(2), b=18.647(3), c=19.616(4) A, alpha=74.38(2)(o), beta=88.18(2)(o), gamma=79.28(2)(o), V=3504(1) A(3); triclinic system; space group: P1. EPR spectra of these solids are identical and show strong antiferromagnetic coupling between the copper atoms, similar to the spectrum obtained for [Cu(2)(II)(niflumate)(4)(DMSO)(2)]. The [Cu(2)(II)(niflumate)(4)(H(2)O)(2)], [Cu(2)(II)(niflumate)(4)(H(2)O)(2)].4DMA, [Cu(2)(II)(niflumate)(4)(H(2)O)(2)].4DMF, [Cu(2)(II)(niflumate)(4)(DMF)(2)], and[Cu(2)(II)(niflumate)(4)(DMSO)(2)] evidenced protection against maximal electroshock-induced seizures and Psychomotor seizures at various times after treatment, consistent with the well known antiinflammatory activities of Cu chelates, but failed to protect against Metrazol-induced seizures while evidencing some Rotorod Toxicity consistent with a mechanism of action involving sedative activity.  相似文献   

20.
Four complexes [Pd(L)(bipy)Cl]·4H2O (1), [Pd(L)(phen)Cl]·4H2O (2), [Pt(L)(bipy)Cl]·4H2O (3), and [Pt(L)(phen)Cl]·4H2O (4), where L = quinolinic acid, bipy = 2,2’-bipyridyl, and phen = 1,10-phenanthroline, have been synthesized and characterized using IR, 1H NMR, elemental analysis, and single-crystal X-ray diffractometry. The binding of the complexes to FS-DNA was investigated by electronic absorption titration and fluorescence spectroscopy. The results indicate that the complexes bind to FS-DNA in an intercalative mode and the intrinsic binding constants K of the title complexes with FS-DNA are about 3.5?×?104 M?1, 3.9?×?104 M?1, 6.1?×?104 M?1, and 1.4?×?105 M?1, respectively. Also, the four complexes bind to DNA with different binding affinities, in descending order: complex 4, complex 3, complex 2, complex 1. Gel electrophoresis assay demonstrated the ability of the Pt(II) complexes to cleave pBR322 plasmid DNA.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号