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Profiles of enzymatic activities were studied using 19 chromogenic substrates for 22 species (211 strains) belonging to the genera Agrobacterium, Alcaligenes, Alteromonas, Flavobacterium and Pseudomonas. The observed patterns of reactions may be useful as an aid in identification of these species and for epidemiological studies.
We have investigated the possibility of growing mutator phages from Pseudomonas aeruginosa on various isolates of Alcaligenes eutrophus. Although none out of 10 A. eutrophus strains were susceptible to infection with any of the phages tested, phage D3112 could be readily transferred in our model strain CH34 by means of an RP4::D3112 plasmid. CH34/RP4::D3112 lysogens were stable and produced phages. However, neither mitomycin C nor UV treatment increased the phage yield.
Studies on siderophore production using Alcaligenes faecalis BCCM ID 2374 revealed hydroxamate and catecholate type of siderophores at 347 microg mL-1. These fractions were purified on Amberlite XAD-4 column, which resulted in the separation of two bands having absorption maxima at 264 and 224 nm. The amount of pure siderophore obtained in powdered form from first and second fraction was 297 and 50 microg mL-1 respectively.
Treatment of the paper factory effluent was done with free and immobilized cells of a phenol degrading Alcaligenes sp. d(2). The free cells could bring a maximum of 99% reduction in phenol and 40% reduction in chemical oxygen demand (COD) after 32 and 20 h of treatment, respectively. In the case of immobilized cells, a maximum of 99% phenol reduction and 70% COD reduction was attained after 20 h of treatment under batch process. In the continuous mode of operation using packed bed reactor, the strain was able to give 99% phenol removal and 92% COD reduction in 8h of residence time The optimum flow rate was 2.5 ml/h and the half life period was 76 h. Even after the complete removal of phenol, the strain could further enhance reduction in chemical oxygen demand, which clearly indicated that in the paper factory effluent, this strain could also oxidize organic matter other than phenol.
He-Ne laser technology was utilized in this study to investigate the response of Alcaligenes faecalis to laser stimulation. The irradiation experiments were conducted by the adjustment of the output power from 5 to 25 mW and the exposure time from 5 to 25 min. The results showed that the survival rate changed regularly with the variety of irradiation dose, and high positive mutation frequency was determined by both the energy density and the output power. The mutant strain AFM 2 was obtained. Phenol biodegradation assay demonstrated that AFM 2 possessed a more prominent phenol-degrading potential than its parent strain, which presumably attributed to the improvements of phenol hydroxylase and catechol 1,2-dioxygenase activities. The phenol of 2000 mgl(-1) was completely degraded by AFM 2 within 85.5h at 30 degrees C. In addition, the cell growth and phenol degradation kinetics of the mutant strain AFM 2 and its parent strain in batch cultures were also investigated at the wide initial phenol concentration ranging from 0 to 2000 mgl(-1) by Haldane model. The results of these experiments further demonstrated that the mutant strain AFM 2 possessed a higher capacity to resist phenol.
Enterobacterial repetitive intergenic consensus (ERIC)-PCR fingerprinting classified 97 phenol-degrading isolates with identical amplified ribosomal DNA restriction analysis (ARDRA) patterns into six genotypic groups. The 16S rRNA gene of the representative isolate of each group had higher than 99.47% common identity with each other and higher than 98% identity with the type strain of Alcaligenes faecalis. PCR-TGGE (temperature gradient gel electrophoresis) analysis of the genes of the largest subunit of the multi-component phenol hydroxylase (LmPH) in each isolate followed with sequencing showed that isolates within each ERIC-PCR group had identical LmPH gene sequences. Among the six different ERIC-PCR groups, two were found to harbor two different LmPH genes encoding low- and high-Ks (affinity constants) phenol hydroxylases, and the low-Ks type LmPH was identical in sequence with one predominant LmPH of the parental activated sludge. Three ERIC-PCR groups had only the high-Ks type and one had no sequence similar to the known LmPHs. Our work suggests that there is no correlation between the phylogenetic groupings of phenol-degrading bacteria and their LmPH genotypes possibly due to extensive horizontal gene transfer of this functional gene.
A novel indole dioxygenase (idoA) gene has been cloned from Pseudomonas alcaligenes PA-10, based on its ability to convert indole to indigo. The chromosomally encoded idoA gene exhibits no similarity to previously cloned naphthalene dioxygenases or to aromatic oxygenases from other species at the nucleotide level. Phylogenetic analysis indicates that the idoA gene product is most similar to an acyl-CoA dehydrogenase from Novosphingobium aromaticivorans. The enzyme encoded by the idoA gene is essential for the metabolism of fluoranthene, since a mutant in which the idoA gene has been disrupted looses the ability to degrade this compound. The idoA gene appears to be constitutively expressed in PA-10, but its expression is also subject to regulation following prior exposure to salicylate and to fluoranthene degradative intermediates.
Alcaligenes faecalis strain No. 4, which has heterotrophic nitrification and aerobic denitrification abilities, was used to treat actual piggery wastewater containing high-strength ammonium under aerobic conditions. In a continuous experiment using a solids-free wastewater (SFW) mixed with feces, almost all of the 2000 NH4+ -N mg/L and 12,000 COD mg/L in the wastewater was removed and the ammonium removal rate was approximately 30 mg-N/L/h, which was 5-10 times higher than the rates achieved by other bacteria with the same abilities. The denitrification ratio was more than 65% of removed NH4+ -N, indicating that strain No. 4 exhibited its heterotrophic nitrification and aerobic denitrification abilities in the piggery wastewater.
PURPOSE: To report a case of persistent polymicrobial postoperative endophthalmitis caused by Alcaligenes xylosoxidans and Propionibacterium acnes in a pseudophakic eye. A. xylosoxidans is a gram-negative bacteria resistant to most antibiotics. METHODS: Case report. RESULTS: A 72-year-old man presented with clinical signs of endophthalmitis on the first postoperative day after a phacoemulsification procedure with posterior chamber intraocular lens, left eye. Initial treatment included topical, subconjunctival, and oral antibiotics. After initial clearing, there was recrudescence of infection on postoperative day 37 that prompted referral of the patient to the Cullen Eye Institute. Treatment at that time included anterior chamber and vitreous taps with intravitreal antibiotic injections. Complete pars plana vitrectomy and intraocular lens explantation were eventually required because of persistent infection with a resistant organism. Cultures from the first procedure grew A. xylosoxidans and P. acnes. Cultures from the vitrectomy grew only A. xylosoxidans. At the final follow-up visit 6 months after the initial procedure. The eye was without inflammation with best-corrected visual acuity of 20/40. CONCLUSION: Both A. xylosoxidans and P. acnes can cause chronic progressive endophthalmitis after cataract extraction often resistant to corrective antibiotic therapy. Successful intervention may require complete vitrectomy with intraocular lens and capsule removal.
PURPOSE: To report a case of Alcaligenes xylosoxidans endophthalmitis and to increase awareness of its potential as an intraocular pathogen. METHODS: An 80-year-old woman in good general health developed A. xylosoxidans endophthalmitis 8 months after an uncomplicated cataract extraction performed at another institution. Eventually, vitrectomy with removal of the intraocular lens and capsule was performed because of recurrent disease after intravitreal antibiotic injections. RESULTS: Microbiologic examination of the vitreous biopsies and capsule disclosed A. xylosoxidans, a motile, gram-negative rod resistant to many antibiotics. CONCLUSION: A. xylosoxidans should be considered as a cause of low-grade endophthalmitis after cataract surgery.
The endo-alpha-N-acetylgalactosaminidase from Alcaligenes sp. could release T-antigen (Ga1 beta 1----3GalNAc), a carcinoma-associated marker from asialo glycophorin and human cells. The released T-antigen from human asialo erythrocytes was determined by thin layer chromatography and gas liquid chromatography. The released T-antigen from human gastric carcinoma cell Kato III was identified by high performance liquid chromatographies with a reverse-phase column and a size fractionation column. Released T-antigen could be analyzed quantitatively by a sensitive method including pyridylamino derivatization and following high performance liquid chromatography. This suggests that the enzyme is useful for detection and determination of T-antigen from cells.
Pulse radiolysis has been employed to investigate the intramolecular electron transfer (ET) between the type 1 (T1) and type 2 (T2) copper sites in the Met144Ala Alcaligenes xylosoxidans nitrite reductase (AxCuNiR) mutant. This mutation increases the reduction potential of the T1 copper center. Kinetic results suggest that the change in driving force has a dramatic influence on the reactivity: The T2Cu(II) is initially reduced followed by ET to T1Cu(II). The activation parameters have been determined and are compared with those of the wild-type (WT) AxCuNiR. The reorganization energy of the T2 site in the latter enzyme was calculated to be 1.6+/-0.2 eV which is two-fold larger than that of the T1 copper center in the WT protein.
Penicillin acylase from Alcaligenes faecalis has a very high affinity for both natural (benzylpenicillin, Km = 0.0042 mM) and colorimetric (6-nitro-3-phenylacetamidobenzoic acid, Km = 0.0045 mM) substrates as well as the product of their hydrolysis, phenylacetic acid (Ki = 0.016 mM). The enzyme is partially inhibited at high benzylpenicillin concentrations but the triple SES complex formed still retains 43% of the maximal catalytic activity; the affinity of benzylpenicillin for the second substrate molecule binding site is much lower (K(S)' = 54 mM) than for the first one. Phenylmethylsulfonyl fluoride was shown to be a very effective irreversible inhibitor, completely inactivating the penicillin acylase from A. faecalis in a few minutes at micromolar concentrations; this compound was used for enzyme active site titration. The absolute values of the determined kinetic parameters for enzymatic hydrolysis of 6-nitro-3-phenylacetamidobenzoic acid (k(cat) = 95 s(-1) and k(cat)/Km = 2.1 x 10(-7) M(-1) s(-1)) and benzylpenicillin (k(cat) = 54 s(-1) and k(cat)/Km = 1.3 x 10(-7) M(-1) s(-1)) by penicillin acylase from A. faecalis were shown to be highest of all the enzymes of this family that have so far been studied.
We provide the first atomic resolution (<1.20 A) structure of a copper protein, nitrite reductase, and of a mutant of the catalytically important Asp92 residue (D92E). The atomic resolution where carbon-carbon bonds of the peptide become clearly resolved, remains a key goal of structural analysis. Despite much effort and technological progress, still very few structures are known at such resolution. For example, in the Protein Data Bank (PDB) there are some 200 structures of copper proteins but the highest resolution structure is that of amicyanin, a small (12 kDa) protein, which has been resolved to 1.30 A. Here, we present the structures of wild-type copper nitrite reductase (wtNiR) from Alcaligenes xylosoxidans (36.5 kDa monomer), the "half-apo" recombinant native protein and the D92E mutant at 1.04, 1.15 and 1.12A resolutions, respectively. These structures provide the basis from which to build a detailed mechanism of this important enzyme.
The structure of the blue copper protein, azurin, from Alcaligenes denitrificans has been determined from an electron density map at a nominal resolution of 3.0 A. Four isomorphous heavy-atom derivatives, prepared with KAu(CN)2, uranyl acetate, Hg(NH3)2Cl2 and KAu(CN)2 + uranyl acetate (a double derivative) were used to calculate phases by the method of isomorphous replacement. The overall figure of merit was 0.61. The two molecules in the asymmetric unit are related by an approximate 2-fold axis. Independent interpretations of the density were made for the two molecules, and the structures have since been partially refined. After 12 refinement cycles, using the Hendrickson-Konnert restrained least-squares program, the R factor is 0.318 for data to 2.5 A resolution and there are no major conformational differences between the two molecules. Refinement is continuing. Eight extended strands of the polypeptide chain form a beta-barrel structure whose topology is the same as that of plastocyanin and the alternative folding proposed for Pseudomonas aeruginosa azurin. As in the latter two proteins, the copper atom forms three short bonds, with His-46 N delta 1, His117 N delta 1 and Cys112 S gamma, and one longer bond, with Met121 S delta, these four ligands forming a very distorted tetrahedron. A possible additional interaction, between copper and the carbonyl oxygen of Gly45, cannot be discounted at the present stage of the analysis. A surface hydrophobic patch, around the edge of the imidazole ring of His117 appears the most likely electron transfer locus. The sequences of azurin and plastocyanin have been aligned and the homology between the two proteins is discussed.
Effects of fermentation conditions on the comonomer composition and its distribution of poly(3-hydroxybutyrate-co-3-hydroxypropionate) [P(3HB-co-3HP)] have been investigated for bacterial synthesis of P(3HB-co-3HP)s by Alcaligenes latus from sucrose and 3-hydroxypropionate (3HPA) mixed carbon sources. Comparison of the microstructures of these samples drew a conclusion that when the concentration of oxygen dissolved (DO) in the fermentation medium was controlled between 5 and 20% (based on the concentration at saturation), the 3HP content and the comonomer compositional distribution (CCD) of the copolymer would not be influenced by the DO values. The concentration of the carbon sources was monitored during the fermentation. The results indicated that the comonomer composition and its distribution of P(3HB-co-3HP)s were interrelated to the amounts of carbon sources transported into the bacterial cells. When the bacteria consumed more sucrose, the more 3HPA they would utilize, and the broader the CCD of the copolymer would be. Furthermore, the efficiencies of the transformation of the two carbon sources to the copolymer constituents were found to be similar.
Previous investigations on the role of the polymerase in the synthesis of poly-3-hydroxybutyrate (PHB) are reviewed, and the results from earlier in vitro studies on the activity and selectivity of the polymerase of Alcaligenes eutrophus are discussed. In the present study the effect of glycerol on stabilizing the polymerase after purification and on eliminating the lag phase in in vitro polymerization reactions of 3-hydroxybutyl CoA (HBCoA), and 3-hydroxyvaleryl CoA (HVCoA) are described. K(M) values were determined for the activity of the polymerase with both HBCoA and HVCoA, and the rates of propagation for both monomers were estimated. With a racemic mixture of HBCoA, the enzyme polymerized only the [R] monomer.
Lamellar single crystals of four random copolymers of (R)-3-hydroxybutyrate with different hydroxyalkanoates: poly(3-hydroxybutyrate-co-8 mol%-3-hydroxyvalerate) (P(3HB-co-8%-3HV)), poly(3-hydroxybutyrate-co-10 mol%-4-hydroxybutyrate) (P(3HB-co-10%-4HB)), poly(3-hydroxybutyrate-co-8 mol%-3-hydroxyhexanoate) (P(3HB-co-8%-3HH)) and poly(3-hydroxybutyrate-co-10 mol%-6-hydroxyhexanoate) (P(3HB-co-10%-6HH)), were grown from dilute solutions of chloroform and ethanol. All single crystals have lath-shaped morphology and the second monomer units seem to be excluded from the P(3HB) crystal, on the basis of the electron diffraction diagrams. The enzymatic degradation of P(3HB-co-8%-3HH) and P(3HB-co-10%-6HH) single crystals was investigated with an extracellular PHB depolymerase from Alcaligenes faecalis T1. Adsorption of an extracellular PHB depolymerase, examined using an immuno-gold labelling technique, demonstrated a homogeneous distribution of enzyme molecules with a low concentration on the crystal surfaces. Enzymatic degradation of single crystals progressed from the edges and ends of crystals to yield narrow cracks along their long axes and the small crystal fragments. Lamellar thicknesses of single crystals and molecular weights of copolymer chains remained unchanged during the enzymatic hydrolysis. The above results support the hypothesis that the hydrophobic adsorption of the enzyme contributes to increase the mobility of molecular chains of single crystals and generate the disordered chain-packing regions. The active-site of PHB depolymerase takes place preferentially at the disordered chain-packing regions of crystal edges and ends with endo-exo enzymatic hydrolysis behaviour, termed processive degradation.