Crystal structure, spectroscopic, and biological study of the copper(II) complex with third-generation quinolone antibiotic sparfloxacin

The neutral mononuclear copper(II) complex with the quinolone antibacterial drug sparfloxacin has been prepared and characterized with IR, UV-vis, and EPR spectroscopies and X-ray crystallography. The interaction of the complex with calf-thymus DNA has also been investigated and the antimicrobial activity has been evaluated against three different microorganisms.     

Synthesis, characterization, antibacterial activity, and interaction with DNA of the vanadyl-enrofloxacin complex

The neutral mononuclear vanadyl complex with the quinolone antibacterial drug enrofloxacin has been prepared and characterized with physicochemical and spectroscopic techniques and molecular mechanics calculations. The interaction of the complex with calf-thymus DNA has also been investigated and the antimicrobial activity has been evaluated against three different microorganisms.     

Structure and biological properties of the copper(II) complex with the quinolone antibacterial drug N-propyl-norfloxacin and 2,2'-bipyridine

The neutral mononuclear copper complex with the quinolone antibacterial drug N-propyl-protected norfloxacin, Hpr-norfloxacin, in the presence of the nitrogen donor heterocyclic ligand 2,2'-bipyridine has been prepared and characterized. The crystal structure of (chloro)(2,2'-bipyridine)(pr-norfloxacinato)copper(II), 1, has been determined and refined with X-ray crystallography. X-band electron paramagnetic resonance (=EPR) spectroscopy at liquid helium temperatures from powdered samples indicates the presence of dimeric units in consistency with the crystal structure. In aqueous solutions of 1 the EPR behavior indicates mixture of dimeric and monomeric species. The antimicrobial activity of the complex has been tested on three different microorganisms and the best inhibition (MIC=0.25mugmL(-1)) has been exhibited against Escherichia coli. The study of the interaction of the complex with calf-thymus DNA has been performed with diverse spectroscopic techniques and has shown that complex 1 is bound to calf-thymus DNA by the intercalative mode. Potential anticancer cytostatic and cytotoxic effects of complex 1 on human promyelocytic leukemia HL-60 and human chronic myelogenous leukemia K562 cell lines have been investigated. Complex 1 shows an increased antiproliferative and necrotic effect on both HL-60 and K562 human leukemia cells in comparison to the free pr-norfloxacin.     

Synthesis and study of physico-chemical properties of a new chiral Schiff base ligand and its metal complex

A new chiral amino acid Schiff base ligand (Salarg) and its metal complex (Mn-Salarg) have been synthesized using l-Arginine, a naturally occurring chiral diamine with two kinds of asymmetric α-, ε-NH₂ groups. This new Salarg-ligand and Mn-Salarg complex are characterized with the help of ultraviolet, fluorescence and infrared spectroscopy. Their crystal systems are determined by X-ray powder diffraction method. The elemental analysis has been carried out by energy dispersive X-ray analysis (EDAX). The presence and percentage of metal in the complex have been detected and estimated by energy dispersive X-ray fluorescence (EDXRF) spectroscopy. Circular dichroism spectroscopy has revealed the chiral nature of the Salarg-ligand and its metal complex. Furthermore, a comparative study of this new chiral Salarg-ligand and its complex has been made with the well known achiral Salen ligand and its metal complex (Mn-Salen).     

Subunit composition of the H+-ATPase complex from anaerobic bacterium Lactobacillus casei

The H+-ATPase complex has been isolated from the membranes of the anaerobic bacterium Lactobacillus casei by two independent methods. 1. The crossed-immunoelectrophoresis of the 14C-labelled ATPase complex against antibodies to a highly purified soluble ATPase has been used. The subunit composition of the complex has been established by autoradiography. The soluble part of L. casei ATPase, in contrast to coupling factor F1-ATPases of aerobic bacteria, chloroplasts and mitochondria which include two kinds of large subunit (alpha and beta), consists of one kind of large subunit with a molecular mass of 43 kDa. Moreover, a minor polypeptide of 25 kDa has been found in the soluble ATPase. Factor F0 of L. casei ATPase complex consists of a 16-kDa subunit and two subunits with molecular masses less than 14 kDa. 2. A dicyclohexylcarbodiimide-sensitive ATPase complex has been isolated from L. casei membranes by treating them with a mixture of octyl glucoside and sodium cholate. The complex, purified by centrifugation on a sucrose density gradient, contains the main subunits with molecular masses of 43 kDa, 25 kDa and 16 kDa and a dicyclohexylcarbodiimide-binding subunit with a molecular mass less than 14 kDa.     

Regulation of cooperative properties of alpha-ketoglutarate dehydrogenase by means of thiol-disulfide metabolism

The redox state of two SH-groups per enzyme subunit has been shown to control the cooperative properties of alpha-ketoglutarate dehydrogenase. These thiols oxidized, alpha-ketoglutarate dehydrogenase does not exhibit any cooperative properties. The enzyme reduction leads to subunit interactions. It has been found that the most effective agent reducing the alpha-ketoglutarate dehydrogenase thiols essential for the cooperativity is dihydrolipoate, one of the intermediates of the overall alpha-ketoglutarate dehydrogenase reaction. The possibility of changing the properties of alpha-ketoglutarate dehydrogenase in the multienzyme complex under the conditions when the lipoic acid integrated into the complex is reduced, has been investigated. Thus, incubation of the alpha-ketoglutarate dehydrogenase complex with NADH has been found to induce the conversion from the non-cooperative form to the cooperative one, presumably through the reduction of lipoic acid bound to the complex in the reaction catalyzed by lipoyl dehydrogenase, the third component of the complex.     

Studies on elongation factor II from calf brain

Elongation factor II (EF2) has been purified from calf brain, and its reactions with guanosine nucleotides and ribosomes have been studied. Its behavior is, in general, similar to that observed with EF2 from other eukaryote sources. Thus, in the presence of GTP or GDP, EF2 interacts with ribosomes to form a ribosome-EF2-GDP complex. Fusidic acid has little effect on the stability of this complex, which suggests that it is more stable than the corresponding complex from prokaryote systems. As assayed by a nitrocellulose filter technique, only GTP, GDP, dGTP and GDPCP are bound to ribosomes dependent on EF2. In the absence of ribosomes, an EF2-GTP or EF2-GDP complex can be detected. Fusidic acid at relatively high concentrations inhibits their formation, but diphtheria toxin in the presence of NAD does not. The EF2-GTP complex has been separated from unbound GTP by gel filtration, and the reactivity of the complex with ribosomes has been investigated. When EF2-GTP is incubated with ribosomes, GTP hydrolysis occurs, and evidence for a ribosome-EF2-GDP complex has been obtained. The results thus suggest that the EF2-GTP complex may be an intermediate in the binding of EF2 to ribosomes. Based on molecular sieve chromatography, it appears that the stability of these complexes is ribosome-EF2-GDP > EF2-GTP > EF2-GDP.     

The etiopathogenetic treatment of experimental tuberculosis using preparations with immunomodulating action

The effectiveness of the complex chemotherapy of experimental tuberculosis in combination with the remedies of pathogenetic therapy has been studied. The immunomodulating action of levamisole, sodium succinate and the positive effect of RNAase on specific resistance in the complex treatment of guinea pigs infected with tuberculosis have been established. On the basis of the pronounced normalization of the systemic and specific resistance characteristics, as well as the clinical effect, the expediency of using levamisole and RNAase in the complex treatment of tuberculosis has been shown.     

The cytoplasmic domain of the cellulose-synthesizing complex in vascular plants

The cytoplasmic domain of the rosette terminal complex has been imaged in situ in patches of plasma membrane isolated from tobacco BY-2 protoplasts. By partially extracting the plasma membrane lipids, cellulose microfibrils were observed through the plasma membrane. Rosette terminal complexes were identified on the basis of their association with the ends of these cellulose microfibrils. The cytoplasmic domain of the rosette terminal complex has been shown to be hexagonal in shape and has been measured to be 45-50 nm in diameter and 30-35 nm tall. These findings demonstrate that the terminal complex does indeed have a substantial cytoplasmic component, and that the hexagonal array observed in the lipid bilayer by freeze fracture is actually only a small part of the overall complex. These findings will allow better modeling of the terminal complex and may facilitate predictions of how many proteins are associated with the rosette terminal complex in vivo.     

The photosensitivity of the malate oxidase system of a pigmented strain and a carotenoidles mutant of Sarcina lutea (Micrococcus luteus)

The effect of white light on the malate oxidase of Sarcina lutea (Micrococcus luteus) membranes has been examined using a carotenoid-containing and a carotenoidless mutant. At least three photosensitive sites have been detected. Two of these are associated with the malate dehydrogenase complex (malate-menaquinone reductase) and are unaffected by membrane carotenoid. A third site which has been detected beyond the dehydrogenase complex, is protected by carotenoid since it can only be demonstrated in carotenoidless systems. A repair mechanism has been found for one of the two sites in the dehydrogenase complex.     

DNA cleavage by a Chromium(III) complex

A new Cr(III) complex with the empirical formula [Cr(Schiff base) (H(2)O)(2)]ClO(4), where the Schiff base is 2, 3-bis?[(2-hydroxy-4-diethylamino) (phenyl) (methylene)]amino?2-butenedinitrile has been synthesized and characterized spectroscopically. Binding of this complex to DNA has been studied using UV-visible spectroscopy. The complex has been found to bind to the major groove of DNA with a binding constant, K = (1.3 +/- 0.2) x 10(3) M(-1). The induced CD spectrum of the complex in the presence of DNA is also indicative of major groove binding. Gel electrophoresis of plasmid DNA in the presence of the complex shows that the complex brings about nicking of the DNA.     

大鼠主要组织相容性复合体RT1研究进展

主要组织相容性复合体在免疫应答中起着重要作用,其多态性研究及应答机制一直是基础免疫学的热点。大鼠基因组草图已经绘制完成,对于主要组织相容性复合体RT1分子水平的遗传学,基因组学,进化及功能方面的研究日渐深入。本文主要介绍了实验大鼠MHC复合体基因的遗传结构,并绘制了其物理结构图谱。重点阐述大鼠的RT1复合体基因的多态性研究,以及RT1复合体对大鼠的移植模型和复杂疾病模型的意义。     

The sorption of a protein-polysaccharide complex isolated from Neisseria meningitidis serogroup B on aluminum hydroxide gels and the immunological activity of the sorbed preparations

The protein-polysaccharide complex, isolated from group B N. meningitidis, is a variant of vaccine for the prophylaxis of group B N. meningitidis infection. In this investigation the influence of the complex of the physical properties of aluminium hydroxide gels, the amount of gel, pH and the duration of sorption on the process of sorption has been studied. Aluminium hydroxide has been shown to produce a stimulating effect on the response of mice to the polysaccharide and protein contained in the complex after immunization made in two injections. Gels with a smaller particle size have been found to possess greater adjuvant activity, as well as greater absorbing activity. The immunological activity of the complex, adsorbed ex tempore, has proved to be no different from that of the complex adsorbed in an hour.     

The Golgi complex

Summary The ultrastructural arrangement of membranes of the Golgi complex has been characterized in Golgi fractions isolated from rat liver. Procedures for isolation of these fractions have been modified to provide a good yield of Golgi membranes (60 to 70%) with greater than 50-fold purification of sialyl transferase, an enzyme specific for the Golgi complex. The isolated membranes appear well preserved and both the dimensions and appearance of the Golgi complex observed by negative staining and in sections of the isolated membranes correlate well with that in liver sections.The Golgi complex consists of a series of platelike structures, each consisting of a central sac or cisterna from which a network of fine tubules arises. The tubules increase in diameter towards the periphery of the plate and are associated with the formation of vacuoles or secretory vesicles. The structure of the Golgi complex has been related to its role in glycoprotein biosynthesis.     

Role of bio-metal Fe(III) in anticancer behaviour of tamoxifen.

Physicochemical, microbial and pharmacological studies on Fe (III)--Tamoxifen complex have been carried out in solid and aqueous phases. On the basis of elemental analysis, polarographic studies, amperometric titrations and IR spectral studies the probable formula for the complex has been worked out to be 1:1, Fe(III)--Tamoxifen. A tentative structure has been suggested to the complex. The metal ligand interaction has been studied using polarographic method at 27 degrees +/- 1 degree C and at ionic strength of mu = 1.0 (KCl). Microbial studies on the complex was carried out against various pathogenic bacteria and fungi using Raper's method. Mouse sarcoma cell line 180 and Balb/C mice were used for the anticancer screening of solid complex, in vitro and in vivo, respectively. The results of microbial and pharmacological studies with the M:Drug complex revealed that the complex is more potent as compared to the pure drug as regards to its anticancer activity. As such Fe (III) Tamoxifen complex may be recommended to the therapeutic experts for its possible use as more potent anticancer drug.     

The Rhodospirillum rubrum cytochrome bc1 complex: redox properties, inhibitor sensitivity and proton pumping.

A detergent-solubilized, three-subunit-containing cytochrome bc1 complex, isolated from the photosynthetic bacterium R. rubrum, has been shown to be highly sensitive to stigmatellin, myxothiazol, antimycin A and UHDBT, four specific inhibitors of these complexes. Oxidation-reduction titrations have allowed the determination of Em values for all the electron-carrying prosthetic groups in the complex. Antimycin A has been shown to produce a red shift in the alpha-band absorbance maximum of one of the cytochrome b hemes in the complex and stigmatellin has been shown to alter both the Em and EPR g-values of the Rieske iron-sulfur protein in the complex. Western blots have revealed antigenic similarities between the cytochrome subunits of the R. rubrum complex and those of the related photosynthetic bacteria, Rb. capsulatus and Rb. sphaeroides. The R. rubrum complex has been incorporated into liposomes. These liposomes exhibit respiratory control and are able to couple electron transfer from quinol to cytochrome c to proton translocation across the liposome membrane in a manner consistent with a Q-cycle mechanism. It can thus be concluded that neither electron transport nor coupled proton translocation by the cytochrome bc1 complex requires more than three subunits in R. rubrum.     

Isolation from yeast of a metabolically active water-soluble form of ergosterol

A water-soluble complex containing ergosterol together with a component of yeast has been isolated. The complex can be isolated from commercial yeast extract to which ergosterol has been added or directly from whole yeast cells. The complexing component has the properties of a large polysaccharide and the binding between the sterol and the polysaccharide appears to be noncovalent. The complex is easily prepared and is stable in aqueous solution; ergosterol in this solution is metabolically available to yeast cells to which it is added.     

Fibrinolytic and anticoagulant complexes of low-molecular heparin with tuftsin]

The complex of immunopeptide taftsin with low-molecular heparin has been obtained. The complex has fibrinolytic and anticoagulant activities in vitro and in vivo after the injection to albino rats.     

Investigation of the reaction of magnesium with p-nitro-o-carboxylazochromotropic acid and the determination of magnesium in plants and in water

The formation of a novel complex between magnesium and p-nitro-o-carboxylazochromotropic acid (NCBAC) has been observed which is sensitive and selective at pH 10.4 in the presence of ethylenediamine and fluoride. The constants of formation of this complex have been determined by a spectral correction technique, and the complexation reaction has been applied to the spectrophotometric determination of trace magnesium in plants and in water with satisfactory results.