Construction and functionalization of fused pyridine ring leading to novel compounds as potential antitubercular agents

A series of fused and functionalized pyridine derivatives were designed, synthesized and tested for their potential antitubercular properties. All these novel compounds were prepared by using multistep methods involving the construction of pyridine ring as a key synthetic step. Some of these compounds were found to be interesting when tested for their antitubercular properties in vitro and one of them appeared as an attractive and potential antitubercular agent.     

Interfacial properties of hydrophilic surfaces of phospholipid films as determined by the method of contact angles. Comparison with cell surfaces

Hydrophilic films of phospholipids were deposited onto plastic substrates (surface-treated for cell cultures) and shown to adhere sufficiently for measuring their interfacial properties by the method of contact angles. Both by absolute magnitude and by their dependence on temperature, the interfacial properties of these phospholipid films were indistinguishable from those determined for black lipid bilayer membranes with a different method by other authors. According to both their vesicular micromorphology and water permeability, the surface films can be interpreted to consist essentially of multibilayer vesicles with the hydrophilic groups facing outward. Treatment of these films with cell-culture medium containing calf serum results in changes of interfacial properties that are very similar to those effected on virus-transformed 3T3 cells (earlier work). These interfacial effects may be attributed essentially to serum proteins (such as albumin) adsorbing to phospholipid or cellular surfaces. The interfacial properties of nontransformed 3T3 cells are much less affected by serum treatment (earlier work), which correlates closely with their higher serum requirement for proliferation. Comparison of these results with those on the interfacial effects of serum on phospholipid films suggests that at least part of the proliferation-stimulating effect of serum is mediated by changes of interfacial properties of cell membranes upon adsorption of serum proteins such as albumin. Treatment of phospholipid films with concanavalin A, an inhibitor of cell proliferation, does not result in effects on their interfacial properties correlating with those on cellular membranes. This confirms previous suggestions that the latter depends on specific binding of concanavalin A to specific carbohydrates on the cell membrane.     

Interfacial properties of hydrophilic surfaces of phospholipid films as determined by the method of contact angles

Hydrophilic films of phospholipids were deposited onto plastic substrates (surface-treated for cell cultures) and shown to adhere sufficiently for measuring their interfacial properties by the method of contact angles. Both by absolute magnitude and by their dependence on temperature, the interfacial properties of these phospholipid films were indistinguishable from those determined for black lipid bilayer membranes with a different method by other authors. According to both their vesicular micromorphology and water permeability, the surface films can be interpreted to consist essentially of multibilayer vesicles with the hydrophilic groups facing outward. Treatment of these films with cell-culture medium containing calf serum results in changes of interfacial properties that are very similar to those effected on virus-transformed 3T3 cells (earlier work). These interfacial effects may be attributed essentially to serum proteins (such as albumin) adsorbing to phospholipid or cellular surfaces. The interfacial properties of nontransformed 3T3 cells are much less affected by serum treatment (earlier work), which correlates closely with their higher serum requirement for proliferation. Comparison of these results with those on the interfacial effects of serum on phospholipid films suggests that at least part of the proliferation-stimulating effect of serum is mediated by changes of interfacial properties of cell membranes upon adsorption of serum proteins such as albumin. Treatment of phospholipid films with concanavalin A, an inhibitor of cell proliferation, does not result in effects on their interfacial properties correlating with those on cellular membranes. This confirms previous suggestions that the latter depends on specific binding of convanavalin A to specific carbohydrates on the cell membrane.     

Chemical and rheological properties of bacterial succinoglycan with distinct structural characteristics

Succinoglycans are bacterial exopolysaccharides with an octasaccharide repeating unit, composed of glucose and galactose in a 7:1 molar ratio of, and non-carbohydrate substituents, including pyruvate, succinate and acetate. The succinoglycans produced by four different strains of Sinorhizobium meliloti, gram-negative soil bacteria, were analyzed for their molecular weight distribution and degree of non-carbohydrate substitution, as well as their chemical properties were related to their rheological properties. These results showed that the ratio of high molecular weight to low molecular weight succinoglycan was varied from 0.50 to 2.36. Degree of succinylation among the bacterial strains was in the range of 0.30–1.90. Therefore, we concluded that each strain produced succinoglycans with different average degrees of polymerization and succinylation; and that these characteristics were correlated to the rheological properties of the solutions. The effect of molecular weight on the rheological properties appeared to be less than that of the succinyl group abundance.     

Enzymes with new biochemical properties in the pectinolytic complex produced by Aspergillus niger MIUG 16

A comprehensive study on the purification and characterization of pectinolytic enzymes produced by Aspergillus niger MIUG 16 on raw materials solid-state fermentation is reported. Five pectinolytic enzymes were purified using a combination of chromatographic techniques. The properties of these homogenous enzymes were analyzed. The purified enzymes were classified with respect to their biochemical properties and substrate specificity. Among these proteins, one revealed polygalacturonase activity, another appeared to be a pectin methylesterase and three were identified as pectate lyases. The capacity of the fungus A. niger to produce pectate lyases with optimum pH in acidic domain was reported for the first time.     

Combination of Nanoholes with Metal Nanoparticles–Fabrication and Characterization of Novel Plasmonic Nanostructures

Small metal nanostructures, especially gold and silver nanoparticles, are known for their interesting optical properties caused by plasmonic effects. Molecular plasmonics, a combination of these optically active nanostructures with the molecular world, opens new possibilities for bioanalytics and (bio-) nanophotonics. Isotropic or anisotropic, homogeneous or heterogeneous metal nanoparticles provide a platform for different, highly defined functional units with interesting optical properties such as plasmon waveguides or molecular beacons. Nanohole arrays in metal layers are another promising component for nanophotonics. New photonic materials were realized from combinations of single metal nanoparticles with individual nanoholes in metals. Atomic force microscopic imaging was used to determine the particle location as well as the lateral dimensions and the topography of the resulting structures. Besides ultramicroscopic characterization of the nanoarrangements, such as nanoparticles positioned in nanoholes, far-field optical methods were also applied to investigate their optical properties.     

Hydrodynamic properties of connective-tissue polysaccharides.

The major hydrodynamic properties of the connective-tissue polysaccharides are those that describe polysaccharide-water interaction as embodied in their osmotic-pressure and hydraulic-conductivity properties. This study shows that, for polysaccharides such as chondroitin sulphate, hyaluronate and the heparin-like polysaccharides, their hydrodynamic properties depend primarily on the presence of the uronic residue and the nature of the glycosidic linkage. Other parameters such as the degree of N-acetylation and sulphation were found not to influence these properties to any great extent. These studies particularly delineate structural-functional aspects of the connective-tissue polysaccharides in terms of their primary structure.     

Comparative Studies of the Cellular Uptake, Subcellular Localization, and Cytotoxic and Phototoxic Antitumor Properties of Ruthenium(II)-Porphyrin Conjugates with Different Linkers

Six water-soluble free-base porphyrin-Ru(II) conjugates, 1-3, and Zn(II) porphyrin-Ru(II) conjugates, 4-6, with different linkers between the hydrophobic porphyrin moiety and the hydrophilic Ru(II)-polypyridyl complex, have been synthesized. The linear and two-photon-induced photophysical properties of these conjugates were measured and evaluated for their potential application as dual in vitro imaging and photodynamic therapeutic (PDT) agents. Conjugates 1-3, with their high luminescence and singlet oxygen quantum yields, were selected for further study of their cellular uptake, subcellular localization, and cytotoxic and photocytotoxic (under linear and two-photon excitation) properties using HeLa cells. Conjugate 2, with its hydrophobic phenylethynyl linker, was shown to be highly promising for further development as a bifunctional probe for two-photon (NIR) induced PDT and in vitro imaging. Cellular uptake and subcellular localization properties were shown to be crucial to its PDT efficacy.     

Ureaplasma felinum sp. nov. and Ureaplasma cati sp. nov. isolated from the oral cavities of cats

Seven ureaplasma strains isolated from the oral cavities of domestic cats (Felis domestica) were characterized and compared with the type strains of the three previously established species of this genus, Ureaplasma urealyticum (humans), Ureaplasma diversum (cattle), and Ureaplasma gallorale (chickens). The feline strains hydrolyzed urea but not arginine or glucose, were membrane bound, lacked cell walls, passed through 0.45-micron membrane filters, required cholesterol for growth, and formed minute (15- to 140-microns) colonies on agar medium. The seven feline strains fell into two distinct groups based on (i) their antigenic properties (determined by using the metabolism and growth inhibition and indirect immunoperoxidase procedures), (ii) their genomic properties (determined by using DNA-DNA hybridization and DNA cleavage pattern procedures), and (iii) their polypeptide profiles (determined by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis analyses). Based on these properties, the two feline groups were unrelated to each other or to the three previously established species, and each group represents a distinct Ureaplasma species. Thus, we propose that ureaplasmas with these phylogenetic and genomic properties be given taxonomic status as Ureaplasma felinum and Ureaplasma cati, with strain FT2-B (= ATCC 49229 = NCTC 11709) and strain F2 (= ATCC 49228 = NCTC 11710) as the type strains, respectively.     

Purification and characterization of rat heart and brain catechol methyltransferase.

In an effort to detect the similarities and differences in the properties of rat heart, brain and liver catechol methyltransferase (S-adenosyl-L-methionine:catechol O-methyltransferase, EC 2.1.1.6), we have determined the cellular distribution of this enzyme activity and extensively purified the soluble and microsomal enzymes present in these tissues. Purification of soluble heart (688-fold) and brain enzymes (240-fold) were achieved using an affinity chromatographic system. The properties of these enzymes were compared with respect to their molecular weights, substrate specificities, inhibitor specificities and immunological properties. The characteristics of the enzyme active sites were investigated using various methyl acceptor substrates and various analogs of S-adenosylmethionine as methyl donors. A series of analogs of S-adenosylhomocysteine was also evaluated as inhibitors of these enzymes. The immunological properties of the purified soluble and microsomal enzymes from heart and brain were investigated using an antibody isolated from rabbits which had been immunized with the soluble rat liver enzyme. In general the properties of catechol methyltransferases isolated from heart and brain were similar to the properties of the enzyme isolated from liver. Some minor differences in substrate and inhibitor specificities were observed which might suggest slight differences in the active sites of these enzymes.     

The Effect of Inkjet Printing over Polymeric Films as Potential Buccal Biologics Delivery Systems

The buccal mucosa appears as a promissory route for biologic drug administration, and pharmaceutical films are flexible dosage forms that can be used in the buccal mucosa as drug delivery systems for either a local or systemic effect. Recently, thin films have been used as printing substrates to manufacture these dosage forms by inkjet printing. As such, it is necessary to investigate the effects of printing biologics on films as substrates in terms of their physical and mucoadhesive properties. Here, we explored solvent casting as a conventional method with two biocompatible polymers, hydroxypropyl methylcellulose, and chitosan, and we used electrospinning process as an electrospun film fabrication of polycaprolactone fibers due to its potential to elicit mucoadhesion. Lysozyme was used as biologic drug model and was formulated as a solution for printing by thermal inkjet printing. Films were characterized before and after printing by mechanical and mucoadhesive properties, surface, and ultrastructure morphology through scanning electron microscopy and solid state properties by thermal analysis. Although minor differences were detected in micrographs and thermograms in all polymeric films tested, neither mechanical nor mucoadhesive properties were affected by these differences. Thus, biologic drug printing on films was successful without affecting their mechanical or mucoadhesive properties. These results open way to explore biologics loading on buccal films by inkjet printing, and future efforts will include further in vitro and in vivo evaluations.     

Interrelation of the enterotoxigenic properties and the antigenic structure of Escherichia

The enzymatic signs and serological characteristics of Escherichia enterotoxigenic strains isolated from patients with acute intestinal diseases and from healthy persons were studied. The cultures were subdivided into 24 enzymatic variants and classified with 48 serogroups and 61 serovars. The enterotoxigenic properties of the strains were compared with their serological characteristics and enzymatic signs. The strains, isolated from different persons and classified with the same serovar, belonged to the same variant with respect to the type of enterotoxin they produced (only thermostable enterotoxin, only thermolabile enterotoxin, or both), were similar in the degree of their toxigenicity and belonged, as a rule, to the same enzymatic variant. The data on the presence of manifest interrelation between the enteropathogenicity of Escherichia and their structure, as well as on the stability of the enterotoxigenic properties of these organisms, indicate that in acute intestinal diseases the determination of Escherichia enterotoxigenic strains can be carried out by common bacteriological techniques with the use of specific agglutinating sera.     

Bile acid sulfates. I. Synthesis of lithocholic acid sulfates and their identification in human bile

Sulfate esters of lithocholic, glycolithocholic, and taurolithocholic acids were synthesized using sulfur trioxide in pyridine; they were purified by crystallization from methanol or ethanol as the diammonium salts, and their chemical compositions, infared spectra, and chromatographic behavior were determined. Strong alkaline hydrolysis of these sulfates, as commonly performed during quantitative and qualitative analyses of conjugated bile salts, was found to result in a number of degradation products, presumably through disruption of the C-O bond of the hydroxyl group and conversion of the original steroid to isolithocholate and other (possibly olefinic) compounds. After oral administration of lithocholate-(14)C to three patients with cholelithiasis, radioactive metabolites having the chromatographic properties of sulfated lithocholates were isolated from bile and, confirming a preliminary report (1), were identified as sulfated glycolithocholate and taurolithocholate by their characteristic chromatographic mobilities during a series of specific hydrolytic procedures and by crystallizing them to constant specific activities with the synthetic sulfates. The fraction of endogenous lithocholate present in bile as the sulfate was calculated for two patients by isotope dilution and was shown to be 41% and 75% of the total. Sulfation can be expected to affect the physiological and pharmacological properties of lithocholates and may, therefore, influence the toxic properties of these compounds.     

Selective sensitivity of the cat striate neurons to cruciform and angular figures of various orientations

Selectivity and invariability of tuning were studied in 51 neurons of the primary visual cortex (area 17); cruciform and angular figures (CF and AF, respectively) of different configurations and orientations were presented in their receptive fields. Twenty-three neurons, or 45% of the studied cells, demonstrated selective sensitivity to these figures. Their responses considerably (2.38±0.36 times, on average) increased, as compared with those evoked by presentation of a single bar of preferred orientation. In the examined group, 2 cells demonstrated sensitivity both to the CF and AF. A wide range of detector properties related to the CF and AF analysis was found in the analyzed neuronal population. Detectors of configuration of these figures are described. Selective sensitivity to the angle between branches of these figures was observed in 17 neurons, and responses of 2 neurons among them showed invariability to orientation of these figures. Four cells were selective for orientation and were insensitive to configuration, and 4 other cells showed no specific sensitivity to either of these properties, but were sensitive to the appearance of a CF itself in their receptive field (these cells were regarded as invariant detectors of crossing nodes). Data inconsistent with the hierarchic principle of detection of the above properties are presented. Possible mechanisms and functional significance of selective sensitivity of striate neurons to the CF and AF are discussed.Neirofiziologiya/Neurophysiology, Vol. 27, No. 5/6, pp. 403–412, September–December, 1995.     

Mycelial paper: A potential resource recovery process?

Eleven species of fungi representative of a broad range of cell-wall compositions were evaluated with respect to their papermaking potential as additives to woodpulp furnishes. Some of these species were also examined for their ability to grow on a spent liquor from the pulp-and-paper industry. Handsheets with various levels of incorporated mycelia exhibited a wide range of species-dependent properties. Behavior of the mycelia in the sheets can be modified to a degree by physical and chemical treatments. The overall results suggest that small amounts (5–10% of the sheet constituents) of mycelia, grown inexpensively on waste effluents, might be incorporated into wood fiber paper without serious deleterious effects on paper strength properties. In some cases improved paper is obtained, and larger quantities of mycelia might be used to impart specific properties to the product.     

Influence of the nature of coupling agents on insulin adsorption on supports grafted with sialic acid for high-performance affinity chromatography

Porous silica exhibits excellent mechanical properties for use as a stationary phase for high-performance liquid chromatography. However, negative surface charges make it unusable in its native state. For this reason, silica beads are coated with dextran polymers carrying a calculated amount of diethylaminoethyl groups. Both the minimization of non-specific interactions and the hydrophilic character of such supports allow their functionalization with biospecific ligands and finally their use in high-performance affinity chromatography of biological products. The use of these modified supports in high-performance affinity chromatography requires a better understanding of various characteristics of stationary phases. For this purpose, several techniques were utilized, in particular, size-exclusion chromatography and adsorption of radiolabelled albumin. These methods provided complementary information on the structure of these supports. Coated silica-based supports were functionalized with sialic acid by means of different coupling agents. The affinity of these supports for insulin was determined by the establishment of adsorption isotherms and by high-performance affinity chromatography, to evidence the relationships between structural characteristics of the supports and their separation properties. The study of interactions between these supports and insulin allowed us to show the importance of the coupling method on the performances of supports in affinity chromatography.     

Injectable and moldable hydrogels for use in sensitive and wide range strain sensing applications

Recently, the use of hybrid double network (DN) hydrogels has become prominent due to their enhanced mechanical properties, which has opened the door for new applications of these soft materials. Only a few of these gels have demonstrated both injectable and moldable capabilities. In this work, we report the mechanical properties, gauge factor (GF) values and demonstrate both the injectability and moldability of a gelatin/polyacrylamide DN hydrogel. We optimized several parameters, such as, gelatin to polyacrylamide ratio, reactant concentrations and metal ion concentration, to produce a gelatin/polyacrylamide hydrogel with superior mechanical properties. The highest water content gel was capable of withstanding strains of 5000% before failure. These gels were facilely injected into molds where they effectively changed shape and maintained similar properties prior to remolding. When 20 mM calcium was doped into a similar gel, a tensile strength of 1.71 MPa was achieved. Aside from improving the mechanical properties of the gels, both Ca²⁺ and Mg²⁺ also improved their conductivity, so they were tested for use as strain sensors. The sensitivity of the hydrogel strain sensors were measured using the GF. For the 20 mM Ca²⁺ hydrogel, these GF values ranged from 1.63 to 6.85 for strains of 100% to 2100% respectively. Additionally, the sensors showed good stability over continuous cyclic stretching, demonstrating their long term reliability for strain sensing.     

The use of deoxyribonucleic acid–cellulose chromatography and isoelectric focusing for the characterization and partial purification of steroid–receptor complexes

1. Two characteristic properties of the specific high-affinity steroid-binding proteins or receptors, their ability to bind to DNA-cellulose and their relatively acidic isoelectric point, have been exploited as a means of purification. These two fundamental properties distinguish the receptors from the steroid-binding proteins in serum and the non-specific low-affinity steroid-binding proteins in hormone-responsive cells. 2. A significant degree of purification of both cytoplasmic and nuclear steroid-receptor complexes can be achieved with practical facility by these procedures. The purity of the receptor complexes is sufficient to enable studies on their possible control of metabolic processes to be investigated in the future. 3. After extensive purification the physicochemical properties of the cytoplasmic androgen-receptor complex, such as sedimentation coefficient, were unchanged. Further, the purified complex fully retained at least one of its fundamental physiological properties, namely the ability to transfer 5alpha-dihydrotestosterone (17beta-hydroxy-5alpha-androstan-3-one) into chromatin in vitro. 4. The methods may also be employed for studying the changes in the structure and properties of the receptor complexes that are an essential prerequisite for the transfer of cytoplasmic receptor complexes into nuclear chromatin. The temperature-dependence of the binding of androgen-receptor complexes into chromatin is essentially due to a major change in cytoplasmic receptor complex before its attachment to nuclear chromatin. 5. The resolution of these analytical procedures was sufficient to enable a critical comparison of the receptor proteins from different male accessory glands to be undertaken. From these studies, no substantial evidence in support of the tissue specificity of androgen receptors could be established; rather the receptors from different androgen-dependent glands were remarkably similar in physicochemical properties. 6. Although the methods were initially developed for the partial purification of androgen-receptor complexes, they are equally suitable for the prompt and extensive purification of oestrogen-receptor and progesterone-receptor complexes.     

Gene expression profiling of cranial sensory ganglia that transmit food intake stimuli

Peripheral cranial sensory nerves projecting into the oral cavity receive food intake stimuli and transmit sensory signals to the central nervous system. They are derived from four cranial sensory ganglia, trigeminal, geniculate, petrosal, and nodose ganglia, each of which contains multiple kinds of sensory neurons with different cell morphologies and neuronal properties. We investigated the complex properties of these neurons from the viewpoint of gene expression using DNA microarrays. The 498 genes were selected from a total of 8,740 genes as showing tissue-dependent expression on the microarray by hierarchical cluster analysis, in which several genes known to be differentially expressed in cranial sensory ganglia are included. This suggests that DNA microarray cluster analysis revealed a number of characteristic genes for sensory neurons in these ganglia. Among the selected 498 genes, 44 genes are associated with neurotransmission, such as neuropeptides, their receptors, and vesicle transport, and 26 are ion channels regulating membrane potentials. The identification of a number of genes related directly to neural properties indicates that these sensory ganglia contain heterogeneous types of neurons with different neural properties.