A cytochrome b-like pigment with a peak at 567 nm in Pseudomonas aeruginosa.

A cytochrome b - like pigment with an absorption peak at 567 nm was detected in Pseudomonas aeruginosa irrespective of whether the organism was grown aerobically or anaerobically under denitrifying conditions. This pigment has not been reported previously for P. aeruginosa but it has been detected in other denitrifying bacteria including closely related Pseudomonas species.     

Role of Iron and Sulfur in Pigment and Slime Formation by Pseudomonas aeruginosa

Media and an analytical scheme have been developed which allow both a qualitative and quantitative estimation of the formation of pyocyanine, related phenazines, pyorubrin, and a blue and a yellow-green fluorescent pigment by Pseudomonas aeruginosa. Use of the defined pyocyanine medium of Frank and DeMoss with sulfate or various organic sulfur sources allowed formation of pyocyanine, related phenazines, and pyorubrin. When sulfite was the sulfur source with or without iron, P. aeruginosa formed either a yellow-green or a blue fluorescent pigment. Formation of fluorescent pigments of P. aeruginosa is related to the ability of sulfite to act as a specific sulfur source. In an investigation of the role of both added iron and sulfur sources, complex patterns of pigment formation were observed. In addition to the fluorescent pigments, sulfite also supported the formation of slime by P. aeruginosa.     

2-Methoxycyclopentyl analogues of a Pseudomonas aeruginosa quorum sensing modulator

Diastereomeric 2-methoxycyclopentyl analogues of a natural quorum sensing signaling molecule from Pseudomonas aeruginosa were synthesized and screened in pigment production assays with P. aeruginosa and Serratia strain ATCC39006.     

Irgasan-induced pigmentation in Serratia marcescens and Pseudomonas aeruginosa.

Two irgasan-resistant micro-organisms (P. aeruginosa and S. marcescens) were used to study the effects of various antibiotic and chemotherapeutic agents on pigment production. These agents included streptomycin, thallium acetate, polymyxin B, hexachlorophene, irgasan, prodigiosin and DMSO (dimethyl sulphoxide). Only irgasan, compared to other drugs and membrane-active agents showed the unique property of inducing pigmentation in both P. aeruginosa and S. marcescens, i.e. prodigiosin in S. marcescens and pyocyanin in P. aeruginosa.     

Effect of Pseudomonas aeruginosa melanin on antibiotic activity]

The properties of microbial melanines are very diverse. Melanine of P. aeruginosa is little studied. The pigment was isolated from a strain of P. aeruginosa possessing all characteristic properties of the species. Interaction of P. aeruginosa melanine with various antibiotics was determined by the method of serial dilutions in beaf-peptone broth, using Staph. aureus 209 as a test-microbe, which was added to the medium in an amount of 10(6) cells to each tube. It was found that P. aeruginosa melanine differed from DOPA-melanine in a concentration of 1 mg/ml and did not change the activity of penicillin, tetracycline, oleandomycin, kanamycin and gentamicin with respect to Staph. aureus.     

Characteristics of hospital strains of Pseudomonas aeruginosa

A total of 745 P. aeruginosa strains from patients with purulent inflammatory processes, 216 strains from the environment of a surgical hospital and 35 strains from carriers were studied with respect to 30 cultural and biochemical signs of P. aeruginosa. 19.8% of the strains were found to form no pigment, and in 14.8% of the strains delayed pigment formation was observed (on days 3-10). The most stable signs were motility (99.6%), growth in Simmons citrate agar (97.6%), growth at 42 degrees C (97.4%), arginine decarboxylase activity (96.8%). In 77.0% of the strains glucose assimilation in Hiss liquid medium, in 85.6% glucose oxidation in the OF test, in 90.8% the formation of urease and in 93.2% the formation of gelatinase were observed. Among the strains isolated from the environment, P. aeruginosa variants, atypical with respect to their main differentiating signs, were isolated significantly more frequently.     

Pyocyanine production by Pseudomonas aeruginosa.

Dextrose enhanced the growth of P. aeruginosa but suppressed the biosynthesis of pyocyanine. The preformed pigment could be released from dead cells. Pigmentation was not correlated directly with number of viable organisms in the culture. High concentration of maltose likewise inhibited pyocyanine production. Maltose contained in medium used for pyocyanine production by P. aeruginosa should be kept in low concentration or omitted.     

C-390 as sole selective agent for isolation of Pseudomonas aeruginosa from hospital waste water

Pseudomonas aeruginosa was recovered (in numbers ranging from 10(2) to 10(5) colony-forming units per millilitre) from heavily contaminated hospital waste water when grown at 41.5 degrees C on a differential medium agar containing 9-chloro-9-(4-diethylaminophenyl)-10-phenylacridan (C-390) at a final concentration of 30 micrograms/mL. The medium appeared to be highly selective for P. aeruginosa with 95-100% of all colonies isolated from four different hospital waste waters being identified as P. aeruginosa. Many strains of P. aeruginosa isolated from hospital waste waters failed to hydrolyse casein when grown on skim milk agar and this medium appeared to restrict pigment production to only pyoverdin (detectable only under ultraviolet light). However, most strains were capable of casein hydrolysis when grown on a modified skim milk medium.     

Distribution of Pseudomonas aeruginosa in a riverine ecosystem

The distribution of Pseudomonas aeruginosa in navigation pool 8 of the upper Mississippi River was investigated by acetamide broth enrichment of water, sediment, and swab (solid-water interface) samples. Among the 152 P. aeruginosa isolates, serological type 1 was most prevalent (34.2%), and a small number (13.2%) showed carbenicillin resistance. Pigmentation was variable, with only 44.7% elaborating typical blue-green pigment. P. aeruginosa was most commonly isolated from sediment, with solid-water interfaces (aufwuchs samples) also exhibiting high frequencies of isolation. Current velocity, oxygen and nutrient availability, surface tension, desiccation, and negative phototropism were important factors in the riverine distribution of this epibacterium.     

Distribution of Pseudomonas aeruginosa in a riverine ecosystem.

The distribution of Pseudomonas aeruginosa in navigation pool 8 of the upper Mississippi River was investigated by acetamide broth enrichment of water, sediment, and swab (solid-water interface) samples. Among the 152 P. aeruginosa isolates, serological type 1 was most prevalent (34.2%), and a small number (13.2%) showed carbenicillin resistance. Pigmentation was variable, with only 44.7% elaborating typical blue-green pigment. P. aeruginosa was most commonly isolated from sediment, with solid-water interfaces (aufwuchs samples) also exhibiting high frequencies of isolation. Current velocity, oxygen and nutrient availability, surface tension, desiccation, and negative phototropism were important factors in the riverine distribution of this epibacterium.     

铜绿假单胞菌色素代谢相关基因的研究

首次应用Mu转座重组技术研究铜绿假单胞菌色素合成与调控的机制。通过一系列的表型筛选,得到8株色素合成能力改变的突变子。经基因克隆、核苷酸测序研究,证明转座子分别插入到hmgA、ptsP、sucC、phzS、phzF1五个基因中。hmgA基因转座失活导致酪氨酸分解代谢中间产物尿黑酸的积累,后四种情况转座突变显著地影响了铜绿假单胞菌最重要的色素绿脓素（pyocyanin）的合成,其中PhzS和phzF1是绿脓素合成过程中的结构基因,ptsP基因是1个磷酸转移酶系统的重要组分,sucC基因的产物是三羧酸循环中的琥珀酰辅酶A合成酶,对后两个基因在色素合成的调控方面可能起到重要作用的报道尚属首例。     

Mapping of mutations affecting pyoverdine production in Pseudomonas aeruginosa

Abstract Pyoverdine, the yellow-green fluorescent pigment produced by Pseudomonas aeruginosa , is a highly efficient siderophore. Pyoverdine-deficient ( pvd ) mutants of P. aeruginosa PAO isolated after mutagenesis were non-fluorescent and unable to grow in the presence of 2.8 mM ethylenediamine-di-( o -hydroxyphenylacetate) (EDDHA). Addition of purified pyoverdine to media containing EDDHA restored growth of pvd mutants. 6 pvd mutations were mapped between catA and mtu -9002 (at 65–70 min on the chromosome map) by R68.45-mediated conjugation. 2 slightly leaky pvd mutations were localised between argC and strA (at 35 min) by transduction. Thus, we have identified at least 2 genes or gene clusters required for pyoverdine production in P. aeruginosa .     

Fatty acids enhanced tubermycin production by Pseudomonas strain 2HS

A new microbial isolate, Pseudomonas 2HS, produced trace amounts of a greenish-yellow pigment when grown aerobically in a 1% yeast extract medium at 30 degrees C and shaken at 250 rpm for 5 days. In contrast, cells produced more greenish-yellow pigment (2.16 mg/15 ml culture) when grown in the presence of 0.5% 12-hydroxyoctadecanoic acid (w/v). The greenish-yellow pigment was identified as phenazine-1-carboxylic acid (tubermycin B), and the Pseudomonas 2HS was identified as P. aeruginosa 2HS. This is the first report that 12-hydroxyoctadecanoic, ricinoleic and other fatty acids can enhance the production of phenazine-1-carboxylic acid by a Pseudomonas species.     

基于感光色素吸收信号的太湖藻类识别

铜绿微囊藻和斜生栅藻是太湖"水华"的主要藻种,基于室内纯铜绿微囊藻、斜生栅藻组成色素的吸收系数,通过四阶微分、标准化系数等方法对太湖水体浮游植物中铜绿微囊藻和斜生栅藻进行识别,并确定其组成比例。结果表明,纯藻组成色素的吸收系数应用于其在太湖水体浮游植物中比例的确定和识别中,能够全面考虑辅助色素的识别作用,较好地避免非色素物质吸收信号的干扰,具有较好的识别效果。太湖水体浮游色素中铜绿微囊藻比例最高,斜生栅藻次之,由夏季向冬季过度中,铜绿微囊藻比例不断减小,斜生栅藻的比例逐渐升高,但铜绿微囊藻比例仍略高于斜生栅藻;铜绿微囊藻的区域分布差异性较小,但时间差异性相对较大,而斜生栅藻恰恰相反,空间分布差异性较大而时间分布差异性较小。       

The physiologic role of pyocyanine synthesized by Pseudomonas aeruginosa

The physiological role of pyocyanine for Pseudomonas aeruginosa was studied. Its synthesis was shown to commence at the retardation growth phase. Pyocyanine was accumulated only in the growth medium. The addition of 2,6-dichlorophenolindophenol accepting the reducing equivalents from coenzyme Q and transferring them to cytochrome c inhibited the pigment accumulation. This was indicative of the connection between pyocyanine synthesis and the level of the reducing equivalents in the cells. Pyocyanine did not accept the reducing equivalents from coenzyme Q in the respiratory chain of P. aeruginosa. Only reduced pyridine nucleotides served as substrates for pyocyanine in the reaction of autooxidation. The kinetic parameters of this reaction and the affinity of NADH dehydrogenase for the substrate were measured. The kinetic data were analysed to show that, under the physiological conditions, pyocyanine could not apparently compete with the respiratory chain for the reducing equivalents and hence directly regulate the level of NAD(P)H in P. aeruginosa cells. In order to keep the oxidising activity at a level necessary for the cells, the latter decreased the content of the reducing equivalents either by synthesizing pyocyanine or owing to the activity of cyanide-resistant oxidase. These processes of releasing the reducing equivalents are in a reciprocal relationship.     

Structure and activity of the Pseudomonas aeruginosa hotdog-fold thioesterases PA5202 and PA2801

The hotdog fold is one of the basic protein folds widely present in bacteria, archaea and eukaryotes. Many of these proteins exhibit thioesterase activity against fatty acyl-CoAs and play important roles in lipid metabolism, cellular signalling and degradation of xenobiotics. The genome of the opportunistic pathogen Pseudomonas aeruginosa contains over 20 genes encoding predicted hotdog-fold proteins, none of which have been experimentally characterized. We have found that two P. aeruginosa hotdog proteins display high thioesterase activity against 3-hydroxy-3-methylglutaryl-CoA and glutaryl-CoA (PA5202), and octanoyl-CoA (PA2801). Crystal structures of these proteins were solved (at 1.70 and 1.75 ? for PA5202 and PA2801 respectively) and revealed a hotdog fold with a potential catalytic carboxylate residue located on the long α-helix (Asp(57) in PA5202 and Glu(35) in PA2801). Alanine residue replacement mutagenesis of PA5202 identified four residues (Asn(42), Arg(43), Asp(57) and Thr(76)) that are critical for its activity and are located in the active site. A P. aeruginosa PA5202 deletion strain showed an increased secretion of the antimicrobial pigment pyocyanine and an increased expression of genes involved in pyocyanin biosynthesis, suggesting a functional link between PA5202 activity and pyocyanin production. Thus the P. aeruginosa hotdog thioesterases PA5202 and PA2801 have similar structures, but exhibit different substrate preferences and functions.     

Nursery Outbreak of Pseudomonas aeruginosa: Epidemiological Conclusions from Five Different Typing Methods

In April 1971, nine cases of Pseudomonas aeruginosa septicemia occurred in a high-risk nursery. The epidemiology of the outbreak was studied by pyocin production, pyocin sensitivity, serological typing, antibiotic susceptibility, and phenotypic properties such as colonial morphology, pigment, and hemolysis. Ten isolates of P. aeruginosa were recovered from 9 newborn infants and from 13 environmental sources. Twenty-one of the 23 isolates had identical pyocin production patterns against 60 different indicator strains and were of the same serotype. These 21 isolates were designated as the "outbreak strain"; the other 2 isolates had no epidemiological significance. The results of pyocin sensitivity, antibiotic susceptibility tests, and phenotypic properties were dissimilar. They would yield incorrect epidemiological conclusions if used alone. The outbreak strain dissociated in vitro and these phenotypic changes accounted for the variable results by the latter three typing methods. Although the precise mode of introduction of the organism into the nursery could not be determined in retrospect, the epidemiological data strongly suggested that one infant contracted a P. aeruginosa infection, and this strain spread throughout the nursery by means of contaminated resuscitation equipment.     

Investigation of persistent colonization by Pseudomonas aeruginosa-like strains in a spring water bottling plant.

Ninety-seven strains, producing a fluorescent pigment under UV light and/or a green diffusive pigment on cetrimide-naladixic acid agar, were isolated from a spring water bottling plant. These strains were presumptively identified as Pseudomonas aeruginosa, but they could not be confirmed as strains of this species nor identified by the API 20NE identification system. The isolates and reference strains were clustered by computer-assisted whole-cell protein sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The numerical analysis of the protein electrophoregrams resulted in the formation of four clusters at a similarity level of 80% and two unclustered type strains. One cluster included strains isolated during a 4-month period and reference strains of several biotypes of P. fluorescens. The remaining isolates formed another cluster with a very high similarity of level, which included two groups of strains based on biochemical characterization by the API 20NE Test System. Strains were typed by random amplified polymorphic DNA (RAPD)-PCR and two different RAPD patterns were obtained, corresponding to each biochemical profile. This persistent colonization seems to be caused by a single species present in the bottling system, with two clonal origins, not related to P. aeruginosa or to any of the other type strains tested. Partial 16S rDNA sequence of a representative strain of one cluster of isolates had a level of similarity of 99.3% with P. alcaligenes. This study shows that characteristics similar to P. aeruginosa on cetrimide-naladixic acid agar can be exhibited by several groups of fluorescent pseudomonads that do not belong to this species, clearly showing that confirmation tests must be performed before a decision regarding the water quality is made.