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PubMed1982

Metabolic accumulation of hydrocarbons by Acinetobacter species.

Acinetobacter HO1-N grown on hexadecane as a sole source of carbon and energy was demonstrated to cytoplasmically sequester this hydrocarbon. Cultures grown with hexadecane and heptadecane accumulated intracytoplasmically both hydrocarbons. The accumulation of specific alkanes was non-specific while the oxidation of the pooled hydrocarbon was highly specific. Naphthalene was highly inhibitory to the growth of this microorganism but slowly co-oxidized in the presence of hexadecane.

Acetates↗
PubMed1982

[Optimization of culture conditions for Acinetobacter calcoaceticus grown on n-alkanes in a laboratory fermenter].

The growth conditions for the cultivation of Acinetobacter calcoaceticus in a commercial laboratory fermenter have been optimized. This was done taking former results of shake cultures as a basis. At the end of the logarithmic phase up to 10 g/l dry weight were obtained. The following culture conditions have been used: The medium contained 10 ml/l n-alkane and 6 g/l NH4Cl. The pH was adjusted to 6.5 and pO2 employed to 70% saturation. A 12 times higher amount of dry weight was observed compared with shake culture technique.

Acinetobacter↗
PubMed1981

Nitrogen utilization in mice bearing Ehrlich ascites tumor treated with Acinetobacter glutaminase-asparaginase.

The effects of Acinetobacter glutaminase-asparaginase (AGA) on protein and energy requirements were evaluated in mice bearing Ehrlich ascites tumors. In an initial experiment with normal mice, a zero protein diet resulted in a significant decrease in carcass nitrogen, liver nitrogen, and carcass energy relative to the animals on a normal, low, or high protein diet. In a second experiment, mice bearing Ehrlich ascites tumors were randomized into diet groups (zero or normal protein) and treatment groups (daily injections of AGA or 0.9% NaCl solution). In both treatment groups, the zero protein diet resulted in significant decreases in weight, liver nitrogen, carcass nitrogen, and carcass energy. Neither tumor nor AGA treatment affected body composition or the efficiency of nitrogen utilization. By Day 8, either the zero protein diet or AGA treatment significantly reduced ascites volume and tumor nitrogen content relative to controls. In a modification of Experiment 2, AGA treatment was stopped on Day 8, and all animals were given a normal protein diet. AGA, but not the zero protein diet, significantly enhanced ultimate survival. These experiments indicate that the requirements and utilization of energy and nitrogen are normal in mice with Ehrlich ascites tumor whether or not they are treated with AGA.

Acinetobacter↗
PubMed1978

[Bacteriemia due to acinetobacter calcoaceticus var. anitratus (author's transl)].

A serious bacteremia caused by Acinetobacter calcoaceticus var. anitratus could be observed. From the clinical point of view the most important symptoms were shivering, high tempeature up to 41 degrees C and clinical signs of acute hepatitis. There were pathological changes in the EEG. Certain signs of an outlayer damage of the heart could be seem in the ECG. The pathogenic microorganism isolated from the blood culture media was classified. Specific antibodies--agglutinines and precipitines--were demonstrated in the patient's serum. A contamination could be excluded so that the bacterium was the causative agent. The diagnostic value of finding antibodies in patient's serum having this type of bacterial infection is discussed.

Acinetobacter↗
PubMed1980

Phase I evaluation of succinylated Acinetobacter glutaminase-asparaginase in adults.

Succinylated Acinetobacter glutaminase-asparaginase (SAGA) has broader antitumor activity than Escherichia coli L-asparaginase in experimental systems; moreover, drug resistance does not develop in tumor cell lines initially sensitive to this enzyme. We have investigated the pharmacology and toxicology of SAGA after both single-dose and serial daily dose injections in 20 adult patients. Glutaminase activity in plasma after i.v. injection of single doses did not follow simple first-order kinetics (half-life during the initial 24 hr was 21 +/- 9 hr. A linear relation was observed between increasing doses of SAGA and resultant levels of plasma enzyme activity and blood glutamate. Assay of whole blood which had been deproteinized immediately following phlebotomy showed that single doses of SAGA lowered glutamine only transiently to nondetectable levels; serial daily doses were required to achieve and maintain continuous glutamine depletion. Reversible depression of the central nervous system, ranging from encephalopathy to coma, occurred in a dose-related manner and was dose limiting. Other prominent reactions included respiratory alkalosis, hyperglycemia, nausea, and vomiting. Transient antitumor effects were noted in two patients with solid tumors and in two patients with leukemia. SAGA causes considerable neurotoxicity in adults which requires close patient monitoring. Phase II studies in leukemic patients are in progress.

Acinetobacter↗
PubMed1994

Generation of a proton motive force by the excretion of metal-phosphate in the polyphosphate-accumulating Acinetobacter johnsonii strain 210A.

The strictly aerobic, polyphosphate-accumulating Acinetobacter johnsonii strain 210A degrades its polyphosphate when oxidative phosphorylation is impaired. The endproducts of this degradation, divalent metal ions and inorganic phosphate, are excreted as a neutral metal-phosphate (MeHPO4) chelate via the electrogenic MeHPO4/H+ symport system of the organism. The coupled excretion of MeHPO4 and H+ in A. johnsonii 210A can generate a proton motive force. In membrane vesicles and deenergized cells, a membrane potential of about -70 mV and transmembrane pH gradient of about -8 mV were formed in response to an imposed outwardly directed MeHPO4 concentration gradient of 120 mV (initial value). The MeHPO4 efflux-induced proton motive force could drive energy-requiring processes, such as the accumulation of L-proline and L-lysine and the synthesis of ATP via the membrane-bound F0F1 H(+)-ATPase. In vivo 31P NMR studies of polyphosphate degradation in anaerobic cell suspensions revealed the presence of a considerable outwardly directed phosphate gradient across the cytoplasmic membrane corresponding to a MgHPO4 concentration gradient of at least 100 mV. This MgHPO4 concentration gradient was maintained for several hours. Thus, energy recycling by MeHPO4/H+ efflux will contribute significantly to the overall production of metabolic energy from the degradation of polyphosphate in A. johnsonii 210A.

Acinetobacter↗
PubMed1994

Purification and properties of a novel type of malonate decarboxylase from Acinetobacter calcoaceticus.

A novel type of malonate decarboxylase which is induced and located in periplasm of Acinetobacter calcoaceticus grown on malonate as sole carbon and energy source was purified to homogeneity. The purified 185-kDa decarboxylase was found to be an oligomer composed of three different polypeptides in a ratio of 2:1:1, designated alpha (65 kDa), beta (32 kDa), and gamma (25 kDa). Optimum pH was 6.8, while pI was 6.39. The enzyme was highly specific for malonate with Km 1.4 mM. This enzyme contained a biotin prosthetic group on alpha subunit which does not seem to be directly related to malonate decarboxylation. The purified enzyme showed almost no activity; activity was restored, however, by treatment with acetic anhydride or malonyl-CoA, which formed an acetyl-enzyme. The 14C-acylated enzyme was isolated by a gel filtration from the reaction mixtures containing [2-14C]malonyl-CoA and the enzyme or [2-14C]malonate, malonyl-CoA, and the enzyme. When treated by thiol-specific reagents, such as N-ethylmaleimide, 5,5'-dinitro-bis(2-nitrobenzoic acid), and 2-nitro-5-thiocyanobenzoic acid, the purified enzyme showed no increase in activity after the acetic anhydride treatment. The thiol-specific reagents failed to inhibit, however, the catalytically active acetyl-enzyme, suggesting that the site of acylation is the thiol group. Further evidence was provided when sodium borohydride inactivated the acetyl-enzyme. These results suggest that malonate decarboxylation by this enzyme may proceed by a catalytic cycle in which the acetyl group on the active enzyme is displaced by malonate, which binds covalently to a thiol group on the enzyme and is subsequently decarboxylated.

Acinetobacter calcoaceticus↗
PubMed1994

[Hydrophobic properties of Acinetobacter calcoaceticus].

Evaluation of hydrophobic properties of 309 strains of Acinetobacter calcoaceticus was performed by a SAT method. Among investigated strains cultured at 22 degrees C, 103 strains were autoaggregating, representing very strong hydrophobic properties. Most of strains aggregated at concentration of 0.4-1.0 M (NH4)2SO4, exhibiting strong hydrophobic activities. Only 38 strains during culture at 22 degrees C exhibited hydrophilic surface properties. Differences between strains of anitratus variety and lwoffii variety were noted. Most auto-aggregating strains, in comparison to number of strains isolated from individual materials, were isolated from purulent materials. It is worth attention that hydrophobic activities were also present in strains isolated from nonclinical materials. Microorganisms of this group cultured at 22 degrees C auto-aggregated in as much as 50%, whereas this occurred during culture at 37 degrees C only in 26%.

Acinetobacter calcoaceticus↗
PubMed1994

[Adhesion of Acinetobacter calcoaceticus to cheek epithelial cells].

Adhesive properties of 309 strains of Acinetobacter calcoaceticus were determined toward cells of cheek epithelium obtained from 13 healthy women. Most of strains adhered in number of > 0-20 bacterial cells for one epithelial cell. Adherence of A. calcoaceticus to cheek epithelium was dependent not only of variety, strain and temperature of bacterial culture, but also of individual properties of epithelial cells obtained from donors. Relation between hydrophobic properties and adherence to cheek epithelial cells in tested bacteria was observed. Strains with very strong hydrophobic properties (auto-aggregating strains) were exhibiting weaker adhesive abilities when compared with strains with lower hydrophobic properties (strains causing no aggregation).

Acinetobacter calcoaceticus↗
PubMed1993

[Hemagglutinating properties of Acinetobacter calcoaceticus].

Hemagglutinating activity was tested in 309 strains of Acinetobacter calcoaceticus with fresh and tannine human, horse, sheep, bovine, chicken and guinea pig erythrocytes. Determinations were performed with 0.1% D-mannose and without it, both in temperature 37 and 22 degrees C. Hemagglutinating activity was exhibited by 75-85% of strains, more frequently cultured at 22 degrees C A. calcoaceticus var. anitratus equally frequently was agglutinating both types of erythrocytes. Strains of A calcoaceticus var. lwoffii were agglutinating only chicken erythrocytes, but were agglutinating all tannin treated erythrocytes. The observed agglutination was mannose-resistant.

Acinetobacter calcoaceticus↗
PubMed1994

Substrate specificity of the two phosphate transport systems of Acinetobacter johnsonii 210A in relation to phosphate speciation in its aquatic environment.

In natural waters and domestic waste waters in which divalent metal ions are present in excess of Pi, H2PO4-, HPO4(2-), and MeHPO4 prevail at pH values physiological for Acinetobacter johnsonii 210A (pH 5.5-8.0). In view of the ability of this organism to extensively accumulate Pi and divalent cations in cytoplasmic polyphosphate granules, the substrate specificity of its two Pi transport systems was studied. The constitutive, proton motive force-driven Pi carrier, previously shown to be dependent on divalent cations, plays a major role in the divalent cation and Pi flux by translocating MeHPO4 rather than Pi. This notion is confirmed by the observation that divalent cations are cotransported with Pi in a 1:1 stoichiometry in proteoliposomes containing reconstituted Pi carrier protein. In contrast, the Pi repressible, periplasmic binding protein-dependent Pi transport system mediates the uptake of H2PO4- and HPO4(2-). Pi uptake, but not MeHPO4 uptake, was stimulated in cells under Pi limitation, and the periplasmic Pi-binding protein has affinity for H2PO4- and HPO4(2-), but not for MeHPO4. When operating in concert, both systems enable A. johnsonii 210A to efficiently acquire Pi from its habitat through uptake of the predominant Pi species.

Acinetobacter↗
PubMed1993

S-adenosylhomocysteine hydrolase from Acinetobacter calcoaceticus: purification and partial characterization.

S-adenosylhomocysteine hydrolase (SAHase) was purified to homogeneity from the Gram negative strain Acinetobacter calcoaceticus 501. The molecular weight of the native enzyme, estimated by gel permeation, was about 288 KDa, while sodium dodecyl sulfate polyacrylamide gel electrophoresis yielded a relative molecular mass of 48 KDa. The determination of the coenzyme content gave 4 mol of NAD+ and 2 mol of NADH per mol of enzyme. The isoelectric point of native SAHase was at pH 5.1. When assayed in the hydrolytic direction, the Km for S-adenosylhomocysteine and the Vmax of the enzyme for this substrate were 84 microM and 357 mumol/min/mg, respectively; in the synthetic direction, instead, the Km for adenosine and the corresponding Vmax value were 1.6 microM and 37 mumol/min/mg. Substrate analogs were tested for their ability to act as inhibitors and inactivators of the enzyme. Among these compounds, 9-beta-arabinofuranosyl adenine (Ara A) appeared as the most powerful competitive inhibitor (Ki = 18 microM) as well as the strongest time-dependent inactivator. The common feature of all the assayed analogs was the presence of the adenine ring in their molecular structure. It can thus concluded that the presence of the adenine moiety is an essential element in substrate and/or inhibitor interaction with this bacterial enzyme.

Acinetobacter calcoaceticus↗
PubMed1993

[Occurrence of species of the Acinetobacter genus in material from patients and in the hospital environment].

370 clinical strains of genus Acinetobacter were classified in accordance of taxonomy of this group of bacteria introduced by Nouvet and Grimont (1986). Most frequent species isolated was A. baumanii (195), followed by A. lwoffii (71), A. junii (79) and A. haemolyticus (27). A. calcoaceticus and A. jonsonii were present only sporadically. A. baumanii was isolated from bronchial secretions (36.9%), sputum (20.5%), blood (8.7%), pus (8.2%) and ur@ine (8.2%). A. lwoffi was isolated above all from throat smears (26.8%), sputum (16.9%), bronchial secretions (16.9%) and urine (16.9%). A. junii was present in sputum (25.7%), blood (17.6%), throat smears (17.6%), bronchial secretions (13.5%) and urine (12.2%).

Acinetobacter↗
PubMed1995

Study of a hydrocarbon-utilizing and emulsifier-producing Acinetobacter calcoaceticus strain isolated from heating oil.

Twenty bacterial strains were isolated from a sample of contaminated heating oil and screened for their ability to use petroleum and several common fuels as the sole source of carbon and energy. One of the isolates, named MM5, was able to grow on petroleum derivatives and brought about an emulsification of those compounds. Gas chromatography studies showed that strain MM5 was able to degrade hydrocarbons of heating oil. MM5 has been tentatively identified as a strain of Acinetobacter calcoaceticus. The fine structure of MM5 was examined by transmission electron microscopy. Incubation in the presence of hydrocarbon substrates resulted in the development of intracellular electron-transparent inclusions. These structures were absent in the non-hydrocarbon cultures studied.

Acinetobacter calcoaceticus↗
PubMed1995

Antibiotic resistance of Acinetobacter calcoaceticus strains isolated from patients treated in intensive care units.

The distribution according to specimens and susceptibility to antimicrobial agents of 481 Acinetobacter calcoaceticus strains isolated from patients treated in intensive care units were studied. They occurred most frequently in tracheal specimens and pus. Using disk diffusion test the strains proved to be multiple resistant to ampicillin (86.3%), azlocillin (86.7%), mezlocillin (84.0%), cefamandole (99.7%), cefoxitin (94.1%), cefuroxime (90.6%), cefoperazone (84.9%), cefotaxime (82.0%), ceftriaxone (81.0%), tobramycin (71.2%), gentamicin (86.2%), chloramphenicol (90.5%) and tetracycline (89.8%). Based on the lowest incidence of resistant strains imipenem (0%), netilmicin (2.6%), amikacin (4.9%), ampicillin+sulbactam (8.9%), amoxicillin+clavulanic acid (29.4%), pefloxacin (26.2%), ciprofloxacin (30.1%), ofloxacin (34.3%), cotrimoxazole (41.6%), carbenicillin (41.2%) or ceftazidime (55.4%) may be the drug of choice in nosocomial A. calcoaceticus infections.

Acinetobacter calcoaceticus↗
PubMed1996

Biofilm formation by Acinetobacter baumannii.

Acinetobacter baumannii, an important nosocomial pathogen is usually found on various surfaces in the hospital environment. In this work, the ability to form biofilms on the surface of sterile coverslips by one clinical isolate of A. baumannii was studied. Sessile cells which adhered to coverslips after being immersed in a nutrient-deficient mineral medium were observed by epifluorescence and scanning electron microscopy at various times of incubation. A rapid increase in the number of sessile cells in young biofilms, followed by a slower increase of such cells was found. At 48 h biofilms were clearly visible and an amorphous material similar to the exopolysaccharide described in some other bacteria covered sessile cells was evident. Biofilm formation by A. baumannii probably favours its maintenance on solid surfaces in the hospital environment and protects the micro-organism against some antibacterial factors.

Acinetobacter↗
PubMed1996

Purification of a lipase from Acinetobacter calcoaceticus AAC323-1 by hydrophobic-interaction methods.

The performance of hydrophobic-interaction chromatography (HIC) for the purification of Acinetobacter calcoaceticus AAC323-1 lipase was compared with that of various aqueous two-phase systems. While a 42% lipase yield with a purification factor of 140 could be recovered by HIC, higher yields were achieved by using aqueous two-phase systems, either those formed by poly(ethylene glycol) and dextran or those based upon the use of a detergent. Triton X-114-based aqueous two-phase partition showed the best performance, with a yield of 81% and a purification factor of 68. Further detergent removal was easily achieved with an adsorbent, with no significant decrease in yields. Owing to its simplicity, the method should be easy to scale-up.

Acinetobacter calcoaceticus↗
PubMed1996

Behaviour of Acinetobacter strains with normal human serum.

The bactericidal activity of normal human serum (NHS) and treated NHS to avoid either the classical complement pathway (CPC) or the alternative complement pathway (APC) was studied with four strains identified as Acinetobacter baumanii. Three of them were sensitive to serum whereas only one was serum resistant. The serum sensitive strains showed different susceptibility mechanisms: one strain was sensitive to both the CPC and the APC and the others were sensitive only to APC. Serum sensitive and serum resistant strains showed on PAGE-SDS and silver strain incomplete profiles of lipopolysaccharides (LPS). In all cases the carbohydrate percentage of LPS was lower than the value corresponding to Salmonella enteritidis with complete profiles of LPS. The strain sensitive to CPC and APC had a lower carbohydrate content. The serum sensitivity of the three strains could be attributed to the presence of incomplete LPS, while the serum resistance could be assigned either to small variations in the LPS composition or to some particular membrane component.

Acinetobacter↗