Showing papers on "Antibacterial activity published in 1989"

Purification, composition, and activity of two bactenecins, antibacterial peptides of bovine neutrophils.

Abstract: Extracts of granules of bovine neutrophils are known to exhibit a marked antibacterial activity in vitro. By a simple, two-step chromatographic procedure, we have resolved two peptide components of the antibacterial system. They were named Bac-5 and Bac-7 from the general term bactenecin and had molecular masses of about 5 and 7 kilodaltons, respectively. Over 45 and 20% of the amino acid residues in the two bactenecins are proline and arginine, respectively. The remaining amino acids are mainly hydrophobic (isoleucine, leucine, and phenylalanine). Both Bac-5 and Bac-7 efficiently kill Escherichia coli, Salmonella typhimurium, and Klebsiella pneumoniae. They also arrest the growth of Enterobacter cloacae (MICs, 25 to 200 micrograms/ml) but not of Proteus vulgaris, Staphylococcus aureus, and Streptococcus agalactiae (MIC, greater than 200 micrograms/ml). Finally, Bac-7 but not Bac-5 has MICs of less than or equal to 200 micrograms/ml for Pseudomonas aeruginosa and Staphylococcus epidermidis. From the comparison between the efficient bactericidal concentrations in vitro and the estimated content of bactenecins in neutrophils (125 ng of Bac-5 and Bac-7 each per 10(6) cells), it is reasonable to conclude that the two cationic peptides may exert a major role in host defense against at least some microorganisms.

Antibacterial activity of human natural killer cells.

Abstract: The in vitro effects of human NK cells on viability of Gram-negative and Gram-positive bacteria was investigated. PBLs depleted of glass-adherent cells showed a significant antibacterial activity that was increased as the concentration of NK cells became higher. Leu-11-enriched cells exhibited the most efficient bactericidal activity. Stimulation of NK cells with staphylococcal enterotoxin B for 16 h produced a significant increase in the antibacterial activity of all NK cells tested. The antibacterial activity of monocyte-depleted cells and Leu-11-enriched cells was also enhanced after culturing in vitro for 16-24 h without exogenous cytokines. Dependence of the antibacterial activity on the presence of serum in the culture medium was not found. Ultrastructural studies revealed close contact between NK cell membranes and bacteria, no evidence of phagocytosis, and extracellular bacterial ghosts, after incubation at 37 degrees C. Supernatants from purified NK cells exhibited potent bactericidal activity with kinetics and target specificity similar to that of effector cells. These results document the potent antibacterial activity of purified NK cells and suggest an extracellular mechanism of killing.

Aminomethyloxooxazolidinyl arylbenzene derivatives useful as antibacterial agents

Abstract: Novel aminomethyloxooxazolidinyl arylbenzene derivatives, wherein the aryl includes the phenyl, substituted phenyl, pyridyl, and substituted pyridyl groups, such as (l)-N-{3-[4-(4'-pyridyl)phenyl]-2-oxooxazolidin-5-ylmethyl}acetamide, possess useful antibacterial activity.

Synthesis and antibacterial evaluation of n-alkyl vancomycins

Abstract: Over eighty N-alkyl vancomycins were synthesized by reductive alkylation of vancomycin with the appropriate aldehydes. The N-alkyl vancomycins exhibit greater antibacterial activity than the corresponding N-acyl vancomycins and the parent antibiotic. Some of these semisynthetic vancomycins are five times more active than vancomycin. The N-alkyl vancomycins also show longer elimination half-lives in rats than vancomycin.

Antibacterial activity from marine microalgae in laboratory culture

Abstract: Culture supernatants and methanolic and hexane extracts of 132 marine microalgae have been screened against six strains of bacteria. In vitro antibacterial activity was detected in 28 of the organic solvent extracts, primarily those of the hexane. The extracts were most effective against Staphylococcus aureus and to a lesser extent Bacillus subtilis. No antimicrobial activity was detected in the culture supernatants and no extract inhibited the growth of Escherichia coli, Streptococcus faecalis, Klebsiella pneumoniae or Pseudomonas aeruginosa.

A convenient, sensitive and rapid assay for antibacterial activity of phytoalexins

Abstract: The antibacterial activity of isoflavonoid and sesquiterpenoid phytoalexins was assayed on thin layer chromatography (TLC) plates using Pseudomonas syringae pv. phaseolicola as the indicator organism in the presence of 2,3,5-triphenyl-tetrazolium chloride (TZC). Addition of glycerol to the overlay nutrient medium, as a carbon source and ultimate electron donor, facilitated the reduction of TZC to pink coloured formazans by bacterial dehydrogenases. Where bacterial growth was inhibited a colourless zone was apparent against a pink background. The test, a modified version of published protocols, gave clear, reproducible results within 24 h

Screening of in vitro antibacterial activity of Terminalia chebula, Eclapta alba and Ocimum sanctum.

Abstract: Study of in vitro antibacterial activity of extracts from the plants T. chebula, E. alba and O. sanctum was carried out by the disk diffusion technique. All showed such activity against human pathogenic Gram positive and Gram negative bacteria. The activity against Salmonella organisms was shown only by T. chebula; against Shigella organisms by T. chebula and E. alha; but not by O. sanctum. The widest spectrum of antibacterial activity was shown by T. chebula. It was also most potent. The antibacterial spectrum of E. alba was in between that of T. chebula and O. sanctum. The narrowest spectrum of antibacterial activity was also most potent. The antibacterial spectrum of E. alba was in between that of T. chebula and O. sanctum. The narrowest spectrum of antibacterial activity was observed in O. sanctum.

Antibacterial Activity of Tea Polyphenols against Clostridium botulinum

Abstract: 茶のタンニン(ポリフェノール)成分として緑茶からカテキン類を4種,紅茶からテアフラビン類を4種分離精製した.これらがボツリヌス菌の芽胞および栄養細胞に対して示す抗菌力を最小発育阻止濃度(MIC)により求めた.芽胞はパウチ法,栄養細胞は画線法でそれぞれを嫌気培養し,ポリフェノール濃度の違いによる菌の生育の有無を調べた.その結果,ガレートカテキン類およびテアフラビン類は100～300ppmの濃度で,ボツリヌス菌の芽胞の発芽および栄養細胞の増殖を阻止した. 同じポリフェノール類が,他の耐熱性有芽胞細菌の芽胞および栄養細胞に対しても抗菌力を示すか否かにつき同じくMIC試験を行なったところ,菌により低濃度で発育が阻止される場合と高濃度でも発育が阻害されない場合とがあり,一定の傾向はみられなかった. なお本報の一部は日本食品工業学会第35回大会シンポジウム10)において発表した.

Synthesis and antibacterial activity of copolymers having a quaternary ammonium salt side group

Abstract: Copolymers with a quaternary ammonium salt side group have been prepared from vinylbenzyl–cetyldimethylammonium chloride and acrylonitrile and their antibacterial activity has been examined with Bacillus subtilis, Staphylococcus aureus, and Escherichia coli. Growth inhibitory effect has been found to increase with the increase in the quaternary ammonium salt concentration in the copolymer. The effect is small on gram-negative bacteria and large on gram-positive bacteria.

Antimicrobial activity of kaurenoic acid derivatives substituted on carbon-15.

Abstract: The antibacterial and antifungic activities of two kaurenic acids, ent kaurenoic acid and cinnamoylgrandifloric acid isolated from a hexane extract of aerial parts of Mikania laevigata, were investigated and compared with the activities of other kaurenic acid derivatives substituted on carbon-15. Only acetylgrandifloric acid (ent-kaur-16-en-15 alpha-acetyloxy-19-oic) and its epimer xylopic acid (ent-kaur-16-en-15 beta-acetyloxy-19-oic) displayed significant antibacterial activity at concentrations greater than or equal to 250 micrograms/ml, the 15 alpha epimer being the most active.

Role of lipids in augmenting the antibacterial activity of benzoyl peroxide against Propionibacterium acnes.

Abstract: Antimicrobial activity and physicochemical properties of benzoyl peroxide (BP) were investigated to determine the mechanism of action for the compound as an antiacne agent. The MICs and MBCs against nine strains of Propionibacterium acnes ranged between 100 and 800 micrograms/ml in a nutrient broth system, with a median fourfold increase in activity demonstrated when lipid was added. The partition coefficient of BP in a 50:50 artificial skin lipid and water system was greater than 2,500, with the concentration of BP soluble in lipid measured at 1.12% and in water at 0.005%. When BP was incubated in the presence of a lipid mixture, reaction products were formed, with evidence that at least some of these compounds possessed antibacterial activity. These results suggest that BP reduces the P. acnes numbers in sebaceous follicles because of good lipid solubility and interaction with the lipid component, the latter property contributing to the antimicrobial activity of the compound in a high-lipid environment.

Aromatic dienoyl tetramic acids. Novel antibacterial agents with activity against anaerobes and staphylococci

Abstract: Streptolydigin (1) and tirandamycin A (2) are typical members of the naturally occurring class of 3-dienoyl tetramic acids. These compounds, which possess potent antibacterial activity particularly against anaerobes, have been shown to inhibit bacterial RNA polymerase. In contrast, tenuazonic acid (5), which lacks a complex dioxabicyclononane moiety and diene chromophore present in 1 and 2, exhibits essentially no antimicrobial activity and has no effect on bacterial RNA polymerase, suggesting that one or both of these structural features may be critical for antibacterial activity. In this paper, we report on a novel series of synthetic dienoyl tetramic acids that lack a complex dioxabicyclononane unit. Several of these compounds, particularly 8T-W, exhibit potent antimicrobial activity against Gram-positive and Gram-negative anaerobes as well as staphylococci. We will discuss the structure-activity relationship for this series of compounds which, in contrast to their natural counterparts, do not inhibit significantly RNA polymerase. We will also discuss preliminary results on the biochemical and microbiological properties of this series of compounds, several of which moderately inhibit supercoiling by DNA gyrase isolated from E. coli H560, although this enzyme has not been established as their target in whole cells. Compound 8W, which is not cross-resistant with DNA gyrase subunit A or B inhibitors or tirandamycin, has also been demonstrated to be rapidly bactericidal.

3'-hydroxybenzoxazinorifamycin derivative, process for preparing the same and antibacterial agent containing the same

Abstract: of the Disclosure A rifamycin derivative having the formula (I): (I) wherein A is a agroup having the formula: in which R1 is an alkyl group having 4 or 5 carbon atoms or an alkenyl group having 3 to 5 carbon atoms, or a group having the formula: in which n is 3 or 4; or a pharmaceutically acceptable salt thereof. The rifamycin derivative (I) exhibits a strong antibacterial activity against Gram-positive bacteria and acid-fast bacteria, and also exhibits a strong antibacterial activity against tubercle bacilli.

Studies on antibacterial agents. I. Synthesis of substituted 6,7-dihydro-1-oxo-1H,5H-benzo(i,j)-quinolizine-2-carboxylic acids.

Abstract: A series of substituted 6,7-dihydro-1-oxo-1H,5H-benzo[i,j]quinolizine-2-carboxylic acids was synthesized and tested for antibacterial activities. Among them, 9-fluoro-6,7-dihydro-5-methyl-8-(4-methyl-1-piperazinyl)-1-oxo-1H,5H- benzo[i,j]quinolizine-2-carboxylic acid (OPC-7241) exhibited potent antibacterial activity against gram-positive and -negative bacteria, including Staphylococcus aureus and Pseudomonas aeruginosa, and 9-fluoro-6,7-dihydro-8-(4-hydroxy-1-piperidyl)-5-methyl-1-oxo-1H, 5H-benzo[i,j]quinolizine-2-carboxylic acid (OPC-7251) showed potent activity characteristically against Propionibacterium acnes.

Synthesis of novel 5-fluoro analogues of norfloxacin and ciprofloxacin.

Abstract: A series of polyfluoro-3-quinolonecarboxylic acids have been synthesized and their in vitro antibacterial activity evaluated. The desired 7-(substituted amino) derivatives were prepared from the 5,6,7,8-tetrafluoroquinolone acids. Conversely, amine displacement occurred primarily at the 5-position when the ester was used. Structure-activity studies indicated that the antibacterial activity was greatest when the N-1 substituent was cyclopropyl and the 7-substituent was 4-methyl-1-piperazinyl. All 5-(substituted amino) derivatives showed poor in vitro activity.

The Modified Model Cavity Method for Assessing Antibacterial Properties of Dental Restorative Materials

Abstract: A new in vitro method for assessing the antibacterial properties of dental restorative materials is described with ratios of test material/ culture medium volume aiming to simulate conditions around a restoration in vivo. Antibacterial activity is determined by the reduction in optical density of the test culture relative to controls. The method was used for assessment of the antibacterial activity of five dental materials of different composition against five oral bacteria. Release of zinc and fluoride from these materials was also measured and correlated with antibacterial activity. There was a general trend toward greater antibacterial activity with increased zinc release, while fluoride release had a significant effect on only one organism. While all the materials, when freshly mixed, were strongly toxic to three out of the five bacteria studied, much of this activity was lost after the materials had set.

In vitro antibacterial effect of the essential oil of Thymus longiflorus Boiss.

Abstract: The essential oil of Thymus longiflorus Boiss was tested for its in vitro antibacterial activity. The results showed antibacterial effects against Gram-positive and Gram-negative bacteria, especially against Pseudomonas fluorescens and Mycobacterium phlei.

Antibacterial Activity of Sirodesmin PL Phytotoxin: Application to the Selection of Phytotoxin-Deficient Mutants.

Abstract: Sirodesmin PL, a phytotoxin and mycotoxin produced by Leptosphaeria maculans, the causal agent of stem-canker disease of crucifers, exhibited antibacterial activity against gram-positive bacteria and particularly Bacillus subtilis. The importance of the disulfide bridge of the molecule in antibacterial activity was demonstrated. A simple and reliable bioassay based on the antibacterial activity of the toxin was performed for screening sirodesmin PL-deficient mutants when grown on solid culture medium. A mutant was selected and found to produce 3,700-fold less toxin than did the wild-type strain. A sensitive procedure for quantification of the toxin by high-pressure liquid chromatography was developed. Levels of product as low as 100 ng could be detected by this procedure.

An in vitro study of the antibacterial and antifungal properties of an irreversible hydrocolloid impression material impregnated with disinfectant.

Abstract: The difficulties associated with the disinfection of alginate (irreversible hydrocolloid) materials have resulted in the development of an irreversible hydrocolloid impression material impregnated with an antimicrobial compound, didecyldimethyl ammonium chloride. This investigation assessed the antibacterial and antifungal properties in vitro of this innovative irreversible hydrocolloid material by using the agar well technique. The microorganisms used were Pseudomonas aeruginosa, Streptococcus mutans, Streptococcus sanguis, Lactobacillus odontolyticus rodriguez, Actinomyces odontolyticus, mixed salivary organisms, and Candida albicans. The results showed an absence of activity against Pseudomonas aeruginosa. Varying degrees of antibacterial activity were exhibited against the other microorganisms. It is concluded that it is not know whether the limited antibacterial and antifungal effect demonstrated in this study is sufficient to prevent bacterial and fungal colonization of the impression surface in the mouth during clinical practice.

9,11-Cyclic acetal derivatives of (9S)-9-dihydroerythromycin A.

Abstract: A series of 9, 11-cyclic acetal derivatives of (9S)-9-dihydroerythromycin A (4) have been prepared and their antibacterial activities compared to those of erythromycin A and 9-dihydroerythromycin A. Many of the cyclic acetal derivatives showed better antibacterial activity than their parent 4. In particular, the acetaldehyde acetal (9-O, 11-O-ethylidene-9-dihydroerythromycin A) (8b) showed good antibacterial activity in comparison with erythromycin A but was not sufficiently improved in vivo to warrant progression.

2,4-Diamino-5-benzylpyrimidines as antibacterial agents. 13. Some alkenyl derivatives with high in vitro activity against anaerobic organisms.

Abstract: A series of 2,4-diamino-5-(3,5-dialkenyl-4-methoxy- or -4-hydroxybenzyl)pyrimidines was prepared from [(allyloxy)benzyl]pyrimidines by Claisen rearrangements, and the resulting allyl phenols were further modified by methylation and rearrangement to 1-propenyl analogues. Analogous 3,4-dimethoxy-5-alkenyl derivatives were prepared by similar techniques. High in vitro antibacterial activity was obtained against certain anaerobic organisms, such as Bacteroides species and Fusobacterium, which was equal to or better than the control, metronidazole, in several cases. The profile was similar against Neisseria gonorrhoeae and Staphylococcus aureus. The 3,5-bis(1-propenyl)-4-methoxy derivative 8 was 1 order of magnitude more active against Escherichia coli dihydrofolate reductase than its saturated counterpart, and it was also more active than trimethoprim, 1. However, it was considerably less active in vitro against the Gram-negative organisms. The 3,4-dimethoxy-5-alkenyl, -5-alkyl, and -5-alkoxy analogues had very high broad-spectrum antibacterial activity. However, pharmacokinetic studies of four of the compounds in dogs and rats and in vivo studies with an abdominal sepsis model in rats showed no advantages over trimethoprim.

Purification and characterization of an antibacterial peptide from venom of lycosa singoriensis

Abstract: An antibacterial peptide -by cosin was purified from the venom of Lycosa singoriensis. The purification scheme was outlined. The lyophilized poison gland was homogenized, extracted and the supernatant was lyophilized again. The solution of lyophilized powder was separated into 11 bands by acidic polyacrylamide gel electrophoresis. The gel was overlaid with viable E. coli to detect antibacterial activity. The fastest migrated band showed the antibacterial activity. The active band was cut down and homogenized, extracted and lyophilized. The antibacterial peptide was further purified on Sephadex G-25 gel filtration and HPLC. The amino acid composition of the purified peptide was determined to contain 43 to 45 amino acid residues. the N-terminal residue was alanine. The basic and hydrophobic ami-no acid residues accounted for close to 1/4 and 1/3 of the total amino acid residues respectively.

N-azamonobactams. 2. Synthesis of some N-iminoacetic acid and N-glycyl analogues.

Abstract: The synthesis of the title compounds has been accomplished. The N-iminoacetic acid analogues (12a and 12b) containing the aminothiazole type side chain exhibited good in vitro antibacterial activity against Gram-negative organisms. The corresponding N-glycyl derivative (17) was not active.