Inhibition of in vitro intracellular growth of Trypanosoma cruzi by dicationic compounds

Dicationic compounds, which are derivatives of pentamidine, are being developed for use as antiprotozoal drugs. These compounds bind to the minor groove of DNA and are thought to inhibit DNA-dependent enzymes and thereby prevent cellular replication by protozoans. The objective of this study was to test the ability of a group of these compounds to inhibit the intracellular and extracellular reproduction of Trypanosoma cruzi in vitro. At present, there are few drugs in use capable of inhibiting the intracellular stages of this parasite, and therefore compounds with this ability would be of value. Cultures of mouse fibroblasts were infected and treated with doses of dicationic compounds, and the numbers of parasites released at the end of the 5- to 7-day growth cycle were determined. Five of the compounds tested were found to be effective at inhibiting T. cruzi growth at doses that were not toxic to the host cells. The compound found most effective (DB709) inhibited parasite release at the low concentration of 0.8 ng/ ml, justifying further study. These results suggest that dicationic compounds may have potential as chemotherapy against T. cruzi infection.     

Structure-activity relationships of halogenated phenylethanolamine and phenoxypropanolamine]

12 compounds from the series of halogenated phenylethanolamines and phenoxypropanolamines were tested at the isolated rabbit jejunum, and the pD2-and pA2-values were determined. All the substances act beta-adrenolytically. Except for 3,4-dichloronoradrenaline, which stimulates the alpha-receptors, all the compounds still have pronounced beta-mimetic effects. The 2,5-dihalogenated phenylethanolamines and phenoxypropanolamines block the beta-receptors at lower concentrations than 2,4-dihalogen derivatives. The weakest beta-adrenolytic effects at the intestine were found with compounds halogenated at the 3,4-position.     

Thermal Degradation of Aromatic Amino Acids

Aromatic amino acids (phenylalanine, tyrosine and tryptophan) were heated at 300°C under nitrogen and volatile compounds generated were examined. Twelve compounds in which many of them have aromatic rings were identified in the volatiles from thermal degradation of phenylalanine. Tyrosine and tryptophan produced some phenols and indoles, respectively, besides several compounds. Formation mechanisms of some compounds were also discussed.     

Effects of phenolic monomers on growth of Acidothermus cellulolyticus

Previous studies on biological pretreatment of switchgrass by solid-state fermentation with Acidothermus cellulolyticus 11B have shown that inhibitory compounds prevent growth on untreated switchgrass. A. cellulolyticus was grown in liquid medium containing cellobiose with phenolic monomers added to determine if the phenolic compounds are one possible source of inhibition. Cinnamic acid derivatives (trans-p-coumaric, trans-ferulic, and hydrocinnamic acids), hydroxybenzoic acids (p-hydroxybenzoic, syringic, and vanillic acids), benzaldehydes (vanillin and p-hydroxybenzaldehyde), and condensed tannin monomers (catechin and epicatechin) were tested at levels up to 20 mM. All compounds exhibited a dose-response relationship and strongly inhibited growth at 20 mM. trans-p-Coumaric acid was found to be the strongest inhibitor of A. cellulolyticus growth, with a specific growth rate of 0.004 h(-1) at 1 mM (0.18 h(-1) without phenolic monomer). GC-MS and HPLC methods were used to confirm the presence of these phenolic compounds in switchgrass and measure the amounts extracted using different conditions. The amounts of phenolic compounds measured were found to be higher than the threshold for growth inhibition. Leaching with water at 55°C was inefficient at removing bound phenolics, whereas NaOH treatment improved efficiency. Phenolic compounds spiked into alkaline pretreated switchgrass were also found to inhibit growth of A. cellulolyticus in solid-state fermentation. However, addition of insoluble polyvinylpolypyrrolidone (PVPP) to switchgrass improved growth of A. cellulolyticus in liquid cultures, providing a possible approach for alleviating microbial inhibition due to phenolic compounds in lignocellulose.     

Current status of aneuploidy testing in Drosophila

Based on the literature on file at EMIC, 181 papers contained material on aneuploidy testing. Initial screening rejected papers providing no data, no negative control and/or poorly designed genetic schemes; 67 papers representing tests of 76 compounds were reported on. Statistical classifications were established as follows: (+)=a statistically significant difference at the 5% level between the treated and control frequencies; (-)=no significant difference at the 5% level when the number of offspring tested was sufficient to have identified an increase of 0.2% over the control with a power of 75%; I=inconclusive= (a) no significant difference at the 5% level but the number of offspring tested was below that necessary to detect an increase of 0.2% with a power of 75%; (b) the nature of apparent complete loss is undetermined; or (c) the nature of the germ cells sampled is not determined. Of the 76 compounds analyzed, calls were made on 34 compounds. 17/34 compounds were positive for chromosome gain (11/34 for chromosome gain and chromosome loss, 6/34 for chromosome gain only). 17/34 compounds were negative for chromosome gain (11/34 for chromosome gain and chromosome loss and 6 for chromosome gain only). Are any fo the compounds found to induce aneuploidy specific for aneuploid induction? 7 or the compounds positive for chromosome gain were positive in one or more tests assaying for other genetic endpoints, and no reliable data exists regarding results in other tests for the remaining 10 compounds; accordingly, the answer to the question awaits further work.     

Effects of cationic and anionic chain compounds on absorption spectra and photochemical activities of chloroplasts

The effects of ionic chain compounds on absorption spectra andphotochemical activities of spinach chloroplasts in suspensionwere investigated and compared with the effects of non-ionicchain compounds previously studied. Two types of spectral changestook place when chloroplasts were treated with ionic compounds.One type of change, not observable with non-ionic chain compoundssuch as carotenoids and fatty alcohols, was in the efficiencyof light absorption; absorption bands over the whole visibleregion were either intensified or flattened at low reagent concentrations.Intensification was observed with anionic fatty acids with 10–18carbon atoms and ascribed to swelling of whole chloroplasts,while flattening was observed with cationic primary and quarternaryamines and ascribed to aggregation of chloroplasts. The othertype of spectral change, transformation of bands observed athigh concentrations of ionic chain compounds, was essentiallysimilar to that found with non-ionic chain compounds. The redand Soret bands of chlorophylls were transformed and absorptionin the range of 490–520 nm decreased on treatment withionic chain compounds. Activity of photosystem I was enhancedby reagents at low concentrations and inhibited at high concentrations,while activity of photosystem II decreased in a middle concentrationrange. These activity changes were correlated to the spectralchanges, although the correlations were less marked than thosefound with non-ionic compounds. This is probably because ofoverlapping of the two types of changes which occur with ionicchain compounds. (Received March 8, 1972; )     

Inhibition of staphylococcal α-toxin. A kinetic evaluation of aromatic polysulphonic acids as inhibitors of haemolysis

1. The effect of a number of aromatic polysulphonic acids on the kinetics of haemolysis of rabbit erythrocyte suspensions by crude staphylococcal alpha-toxin was studied at pH8.6 and 6.8. 2. All of the inhibitory compounds caused an increase in the prelytic lag time (tau) of the sigmoid haemolysis curves, an increase in the time to reach 50% haemolysis (t((1/2))) and a decrease in the maximum rate of haemolysis (R(max.)). The most inhibitory compounds caused a 50% decrease in R(max.) at concentrations between 0.1 and 0.2mm. 3. The effect of pH varied considerably: compounds (I) and (II) were almost equally inhibitory at both pH values, compounds (IV) and (IX) were more inhibitory at pH6.8 than at pH8.6, and compounds (VII), (VIII), (X), (XI) and (XII) were more inhibitory at pH8.6. 4. Increased time of premixing alpha-toxin with compound (I) caused increased inhibition. 5. An attempt was made, where possible, to relate the inhibitory activity to the structure of the test compound.     

Impact of maturity on phenolic composition and antioxidant activity of medicinally important leaves of <Emphasis Type="Italic">Ficus carica</Emphasis> L.

Ficus carica L. is one of the oldest trees belonging to the mulberry family. It has both nutritional and medicinal benefits, as it is a source of potential bioactive compounds. Fig leaves were collected at four maturation stages, to evaluate the variation in polyphenolic compounds, antioxidant activity, and different pigments level. Polyphenols were identified using HPLC–DAD. Different pigments level, total phenolic contents, and radical scavenging activity were quantified. The HPLC analysis revealed the presence of fourteen polyphenolic compounds in the fig leaves. Quercetin-3-glucoside, caftaric acid, quercetin-3, 7-diglucoside, and coumaroyl-hexose were the major phenolic compounds. Kaempferol-3-O-sophorotrioside, cichoric acid and sinapic acid glucoside were identified for the first time. Significant quantitative changes were observed during maturation, particularly in polyphenolic compounds. There were significant changes in pigments level, total phenolic contents, and radical scavenging activity. It was observed that fig leaves are a rich source of polyphenolic compounds during all stages of maturation.     

Structural specificity of aromatic compounds with special reference to mutagenic activity in Salmonella typhimurium--a series of chloro- or fluoro-nitrobenzene derivatives

The mutagenicity of 21 chloro- or fluoronitrobenzene compounds and 9 chloro- or fluorobenzene compounds in Salmonella typhimurium (strains TA98, TA1538, TA1537, TA100 and TA1535) was examined. The tests were carried out under the conditions of absence and presence of liver microsomal activation. 15 nitro-group compounds had mutagenic activity; above all, compounds of fluoronitrobenzene were mutagenic for both types of strain. On the other hand, chloronitrobenzene compounds were mutagenic for base-pair substitution strains only. Mutagenic activity was exhibited by all compounds having a chloro or fluoro substituent at the para and ortho position in the nitrobenzene nucleus. All compounds without a nitro substituent showed no mutagenic activity.     

Inhibition of cellular proliferation by diterpenes, topoisomerase II inhibitor

We examined the effects of 12 terpene compounds derived from the roots of Euphorbia kansui on the proliferative activity of Xenopus embryo cells. Eight of these compounds showed significant inhibition of cellular proliferation even at low concentrations, while four of them needed to be present at higher concentrations to inhibit cellular proliferation. In order to define the mechanism of inhibition of cellular proliferation by these compounds, the effects of diterpene compounds on the activity of topoisomerase II were measured. Most of the diterpene compounds that inhibited cellular proliferation also inhibited topoisomerase II activity.     

Artificial ribonucleases: from combinatorial libraries to efficient catalysts of RNA cleavage

Combinatorial libraries of small organic compounds capable of cleaving RNA were synthesized. The compounds contain benzene ring substituted with two residues of bis quaternary salt of diazabicyclo[2.2.2]octane (DABCO) bearing hydrophobic fragments of different length and structure, attached to DABCO at the bridge position. These compounds, lacking traditional functionalities involved in transesterification reaction, exhibit pronounced RNA cleavage activity. To identify the most active artificial ribonucleases, sublibraries and truncated libraries, containing compounds lacking one of substituents were synthesized. Analysis of ribonuclease activity of truncated libraries resulted in identification of the most active compounds, which are characterized by the presence of at least one long oligomethylene substituent.     

Bacterial diversity of a cyanobacterial mat degrading petroleum compounds at elevated salinities and temperatures

Cyanobacterial mats of the Arabian Gulf coast of Saudi Arabia experience extreme conditions of temperature and salinity. Because they are exposed to continuous oil pollution, they form ideal models for biodegradation under extreme conditions. We investigated the bacterial diversity of these mats using denaturing gradient gel electrophoresis and 16S rRNA cloning, and tested their potential to degrade petroleum compounds at various salinities (fresh water to 16%) and temperatures (5 to 50 degrees C). Cloning revealed that c. 15% of the obtained sequences were related to unknown, possibly novel bacteria. Bacteria belonging to Beta-, Gamma- and Deltaproteobacteria, Cytophaga-Flavobacterium-Bacteroides group and Spirochetes, were detected. The biodegradation of petroleum compounds at different salinities by mat microorganisms showed that pristine and n-octadecane were optimally degraded at salinities between 5 and 12% (weight per volume NaCl) whereas the optimum degradation of phenanthrene and dibenzothiophene was at 3.5% salinity. The latter compounds were also degradable at 8% salinity. The same compounds were degraded at temperatures between 15 and 40 degrees C but not at 5 and 50 degrees C. The optimum temperature of degradation was 28-40 degrees C for both aliphatics and aromatics. We conclude that the studied microbial mats from Saudi Arabia are rich in novel halotolerant and thermotolerant microorganisms with the potential to degrade petroleum compounds at elevated salinities and temperatures.     

Isolation and identification of two isomeric forms of malonyl-coenzyme A in commercial malonyl-coenzyme A

Two isomers of malonyl-coenzyme A (malonyl-CoA) were detected in a commercial preparation of malonyl-CoA. These compounds were separated by preparative high-performance liquid chromatography (HPLC) and characterized by HPLC/ultraviolet (UV)/mass spectrometry. Both compounds had a UV absorbance maximum at 259-260 nm. Both compounds underwent negative electrospray ionization to produce a [M-H](-)quasi-molecular ion at m/z 852 and both compounds underwent collision-induced dissociation to produce a characteristic fragment at m/z 808, all consistent with the structure of malonyl-CoA. Nuclear magnetic resonance spectrometry showed that the two chromatographically distinguishable malonyl-CoAs are structural isomers: the major component is the naturally occurring malonyl-CoA and the contaminant is 3'-dephospho- 2'-phospho-coenzyme A.     

Early diagenesis of organic matter in lacustrine sediments in terms of methane fermentation

The amounts of organic compounds such as amino acids (proteinaceous substances), fatty acids, and sterols in lacustrine sediments were found to decrease greatly from the mud‐water interface to depths of 20 cm and less at greater core depths. The amounts of methane produced by microbial activity in subsamples incubated for 40 days at 27°C were also found to decrease with core depth, apparently limited by the exhaustion of organic substrates subject to methane fermentation. Decomposition rates of certain organic compounds added to sediment samples were determined by incubation experiments at different temperatures for 40 to 450 days. Experimental results with mixed cultures of microorganisms in lacustrine sediments indicated the following: (a) The marked decomposition of organic compounds such as amino acids, fatty acids, and sterols in the lacustrine sediments resulted mainly in the formation of methane, (b) Unsaturated compounds were more readily decomposed with the ultimate formation of methane than saturated compounds, (c) The susceptibility of saturated fatty acids to methane formation decreased in proportion to their molecular weights.     

Spectrophotometric study on the oxidation of rutin by horseradish peroxidase and characteristics of the oxidized products

Rutin (3',4',5,7-tetrahydroxyflavone-3-rutinoside) was oxidized by a horseradish peroxidase-H2O2 system to an ascorbate-reducible product which had an absorption maximum at about 290 nm and a shoulder at about 440 nm at pH 4. At pH 7.8, ascorbate-reducible compounds and sodium hydrosulfite-reducible and -nonreducible compounds were formed by the oxidation. The ascorbate-reducible compounds consisted of at least two components, the absorption bands of which were at 460-480 nm and about 620 nm. The sodium hydrosulfite-reducible compounds also consisted of two components, and one of the components which had an absorption maximum at about 480 nm seems to be formed from the ascorbate-reducible component of an absorption maximum at the blue region by a nonenzymatic reaction. A mixture of oxidized products of rutin formed by tert-butyl hydroperoxide-dependent oxidation was similar to that formed by the enzymatic reaction. It is discussed that the 3'- and 4'-OH groups of rutin were oxidized by the horseradish peroxidase-H2O2 system and that the oxidized product which could be reduced by ascorbate is an o-quinone derivative.     

Synthesis of modified steroids as a novel class of non-ulcerogenic, anti-inflammatory and anti-nociceptive agents

The identification of compounds able to treat both pain and inflammation with limited side effects is one of the prominent goals in biomedical research. This study aimed at the synthesis of new modified steroids with structures justifying non-ulcerogenic, anti-inflammatory and anti-nociceptive activities. The steroid derivatives were synthesized via straightforward and efficient methods and their structures were established based on the analytical and spectral data. The in vivo anti-inflammatory, anti-nociceptive and anti-ulcerogenic activities of some of these compounds were studied. The newly synthesized compounds 8b, 19b, 24 and 31a showed anti-inflammatory, anti-nociceptive and anti-ulcerogenic activity with various intensities. Oedema was significantly reduced by either dose 25 or 50 mg/kg of all tested compounds at 3 and 4 h post-carrageenan. Compound 19b was the most effective in alleviating thermal pain. The analgesic activity of either dose of the compounds 8b, 24, 31a as well as the high dose 19b was significantly higher than that for indomethacin (IND). Gastric mucosal lesions caused in the rats by the administration of 96% EtOH and IND were inhibited by all tested compounds administered at (50 mg/kg) dose in the study.     

Synthesis and biological activity of mustard derivatives of combretastatins

A series of chimeric compounds bearing the combretastatin and the nitrogen mustard cores were synthesized. All the compounds were cytotoxic and inhibited tubulin polymerization. When combretastatin was joined to chlorambucil via an ester linkage, the resultant compound proved to be significantly more potent than the two compounds put together. When combretastatin was joined to nitrogen mustard via an ether linkage or when a true hybrid was synthesized, loss of potency was observed. Nonetheless, these latter compounds appeared to be more efficacious and surprisingly were able to inhibit tubulin depolymerization at high concentrations.     

Growth of Pseudomonas aeruginosa in tap water in relation to utilization of substrates at concentrations of a few micrograms per liter.

Five Pseudomonas aeruginosa strains were tested for the utilization of 47 low-molecular-weight compounds as their sole sources of carbon and energy for growth at a concentration of 2.5 g/liter. Of these compounds, 31 to 35 were consumed. Growth experiments in tap water at 15 degrees C were carried out with one particular strain (P1525) isolated from drinking water. This strain was tested for the utilization of 30 compounds supplied at a concentration of 25 microgram of C per liter. The growth rate (number of generations per hour) of strain P1525 in this tap water was approximately 0.005 h-1, and with 10 compounds it was larger than 0.03 h-1. An average yield of 6.2 x 10(9) colony-forming units per mg of C was obtained from the maximum colony counts (colony-forming units per milliliter). The average yield and maximum colony count of strain P1525 grown in tap water supplied with a mixture of 45 compounds, each at a concentration of 1 microgram of C per liter, enabled us to calculate that 28 compounds were utilized. Growth rates of two P. aeruginosa strains (including P1525) in various types of water at 15 degrees C were half of those of a fluorescent pseudomonad. The concentrations of assimilable organic carbon calculated from maximum colony counts and average yield values amounted to 0.1 to 0.7% of the total organic carbon concentrations in five types of tap water. The assimilable organic carbon percentages were about 10 times larger in river water and in water after ozonation.     

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 and evaluation of antitubercular activity of glycosyl thio- and sulfonyl acetamide derivatives

A series of glycosyl thioacetamide and glycosyl sulfonyl acetamide derivatives have been prepared following a convenient reaction protocol and evaluated for their antitubercular activity against Mycobacterium tuberculosis H₃₇Rv. Amongst 32 compounds evaluated 3 compounds were effective in inhibiting mycobacterial growth at MIC of 6.25 μg/mL, 6 compounds at MIC of 3.125 μg/mL and 1 compound at MIC of 1.56 μg/mL. All active compounds were found nontoxic in Vero cell lines and mice bone marrow macrophages.