Lytic Action of B-enzyme on Pseudomonas aeruginosa

B-enzyme was produced by Bacillus subtilis YT–25 and lysed the native cells of Pseudomonas aeruginosa extensively in the presence of NLF (Native Cell-Lytic Factor). NLF was a peptide which was also produced by B. subtilis YT–25. It was found that B-enzyme hydrolyzed the peptidoglycan of P. aeruginosa eventually to disaccharide units. Because the reducing end of the enzymatic digest was muramic acid, B-enzyme seemed to be an endo-N-acetyl-muramidase. Whereas, egg white iysozyme which was an endo-N-acetylmuramidase hardly lysed the native cells of P. aeruginosa. Specific activity of B-enzyme for the murein of P. aeruginosa was higher than that of egg white Iysozyme in the buffer of low ionic strength and the surface components of P. aeruginosa did not affect the activity of B-enzyme but strongly inhibited the activity of egg white Iysozyme. These facts seemed to explain the superiority of B-enzyme to egg white Iysozyme in the lysis of the native cells of P. aeruginosa.     

The Action of Ethylenediaminetetra-acetic Acid on Pseudomonas aeruginosa

It has been shown that ethylenediaminetetra-acetic acid (EDTA) has a direct bactericidal action against strains of Pseudomonas aeruginosa and Alcaligenes faecalis . The action against Ps. aeruginosa is considered to take the form of competition for a metal essential to the integrity of the cells: some of the factors influencing this antibacterial action have been discussed. From a study of the release of solutes from cells of Ps. aeruginosa , it was concluded that the action of EDTA takes place at the cell wall of the organism: an effect by EDTA on the isolated walls of sensitive organisms has been demonstrated.     

Combined Action of Carbenicillin and Gentamicin on Pseudomonas aeruginosa In Vitro

The minimal inhibitory and minimal bactericidal concentrations of carbenicillin and gentamicin were determined for 10 strains of Pseudomonas aeruginosa isolated from the urinary tract. Combinations of the two drugs were tested for possible enhanced activity. Such enhancement was demonstrated in the inhibitory activity of combinations for eight strains. Striking bactericidal activity against five strains was achieved by the combination, whereas neither drug alone in low dosage was capable of bactericidal action. The possible mode of action and the possible merit of pursuing these preliminary findings are discussed.     

Combined Action of Sulfamethoxazole, Trimethoprim, and Ethylenediaminetetraacetic Acid on Pseudomonas aeruginosa

Potentiation of the sulfamethoxazole-trimethoprim combination by ethylene-diaminetetraacetic acid inhibited, in vitro, four strains of Pseudomonas aeruginosa which were resistant to the sulfamethoxazole-trimethoprim combination alone.     

Biodegradation of 8-anilino-1-naphthalenesulfonic acid by Pseudomonas aeruginosa

Pseudomonas aeruginosa, isolated from soil near tannery effluent was able to degrade 8-anilino-1-naphthalenesulfonic acid (ANSA), a sulfonated aromatic amine. The organism degraded this amine up to a concentration of 1,200 mg l⁻¹ using glucose and ammonium nitrate as carbon and nitrogen sources respectively. The degradation started when the organism reached its late exponential growth phase. Salicylic acid and β-ketoadipic acid were identified as intermediate compounds using HPLC and GC–MS and provide evidence for ortho pathway reactions. Further proof for the pathway is obtained from the dioxygenase activity of the strain growing exponentially in medium with ANSA and glucose.     

8-azaguanine and flavinogenesis in Eremothecium ashbyii.

8-Azaguanine (10- minus 4 M) supplementation in synthetic medium inhibited flavinogenesis in Eremothecium ashbyii to far greater extent (68per cent) than the growth (25 per cent). That enzymes comprising the biosynthetic pathway of riboflavin are synthesized during early growth phase of the organism is supported by the data presented. 8-Azaguanine mediated inhibition in flavinogenesis was closely related with decreased levels of ribose-5'-phosphatase, ribose reductase and ribitol kinase, the enzymes involved in supplying ribitol for flavinogenesis. Addition of guanine and not ribitol during early growth phase to 8-azaguanine-added cultures released the inhibition of riboflavin synthesis and restored the enzyme levels in the presence of the antimetabolite.     

Efficacy of 8 disinfectants on 3 types of surfaces contaminated by Pseudomonas aeruginosa

The disinfecting capacity of eight commercial chemical products was evaluated by the use--dilution method given by the Associated of Official Analytical Chemists (AOAC) on three types of surface material (steel, aluminum, and plastic). For most products tested the limit concentration was 10 times higher for disinfecting aluminum and plastic surfaces than stainless steel. As observed on the scanning electron microscope, the number of bacteria deposited on the surface and the production of extracellular material on polypropylene by Pseudomonas aeruginosa ATCC 15442 would explain the observed differences. The applicability of the AOAC method or other techniques for the evaluation of the disinfecting capacity on different surfaces is discussed.     

Eremothecium ashbyii mutants resistant to 8-azaguanine. II. Mutants with different degrees of resistance to 8-azaguanine]

Guanine, unlike adenine and hypoxanthine, can not eliminate the inhibitory effect of adenine analogues on the growth and flavinogenesis of Eremothecium ashbyii. Guanine does not restore riboflavin synthesis inhibited with 5-10(-3) M 8-azaguanine. Low adenine concentrations (10(-4)-3-10(-4) M), which do not influence the inhibitory effect of 5.-10(-3) M 8-azaguanine, restore the riboflavin synthesis in combination with guanine. On the basis of the data obtained as well as the data of biochemical analysis it is concluded that the riboflavin producer studied lacks guanosinemonophosphate reductase. The mutants resistant to various concentrations of 8-azaguanine have been obtained. In all mutants resistant to 8-azaguanine the efficiency of the incorporation of 14C-guanine and 14C-adenine into mycelium is decreased as compared with the susceptible strain. The mutant Azg-R 10 resistant to high (3-10(-3) M) concentrations of 8-azaguanine, 8-azaadenine and 2,6-diaminopurine secretes inosine-like compounds when grown in a synthetic medium. The stepwise increase of the mutant resistance to 8-azaguanine from 10(-4) M TO 3-10(-3) M did not result in further enhancement of riboflavin synthesis.     

8-azaguanine and flavinogenesis in Eremothecium ashbyii

8-Azaguanine (10⁻⁴ M) supplementation in synthetic medium inhibited flavinogenesis in Eremothecium ashbyii to far greater extent (68%) than the growth (25%). That enzymes comprising the biosynthetic pathway of riboflavin are synthesized during early growth phase of the organism is supported by the data presented. 8-Azaguanine mediated inhibition in flavinogenesis was closely related with decreased levels of ribose-5′-phosphatase, ribose reductase and ribitol kinase, the enzymes involved in supplying ribitol for flavinogenesis. Addition of guanine and not ribitol during early growth phase to 8-azaguanine-added cultures released the inhibition of riboflavin synthesis and restored the enzyme levels in the presence of the antimetabolite.