Metabolism of dicarboxylic amino acids and their amides in bacteria of the genus Citrobacter]

In 58 Citrobacter strains the pathways of the utilization of dicarbonic amino acids and their amides were studied. These organisms were found to be incapable of decarboxylating glutaminic and asparaginic acids, as well as their amides. All the strains could actively desamidizate asparagine. Not all of these strains showed glutaminase activity. Aspartate-aminotransferase occurred twice as often as alanine-aminotransferase, the level of activity being approximately the same. The Citrobacter strains desamidizated asparaginic acid with great constancy, but only in 1/3 of them this reaction occurred via an aspartase route. The desamidization of asparaginic acid in Citrobacter seemed to proceed in different ways. The desamidization of glutaminic acid was observed only in a part of the strains, and the reaction proceeded less actively.     

Chlorophenol and chlorobenzoic acid co-metabolism by different genera of soil bacteria

1. FourPseudomonas strains, anAchromobacter sp., threeNocardia strains,Mycobacterium coeliacum and aBacillus sp., grown on either phenol or benzoic acid as sole carbon source, were tested for co-oxidation of monochlorophenols and monochlorobenzoates respectively.
2. ThePseudomonas spp.,Nocardia spp.,M. coeliacum and theBacillus sp. showed O₂-uptakes in the presence ofo-, m- orp-chlorophenol and oxidised them to either 3- or 4-chlorocatechol.
3. Benzoate-grown cells of the threeNocardia spp. and three of the pseudomonads absorbed O₂ only in the presence ofm-chlorobenzoate, 4-chlorocatechol being identified as the oxidation product in two cases. One pseudomonad gave some O₂-uptake also in presence ofp-chlorobenzoate.
4. Benzoate-grownBacillus cells gave O₂-uptakes with eitherm- orp-chlorobenzoate and the former was oxidised to 5-chloro-2,3-dihydroxybenzoic acid via 5-chlorosalicylic acid, thus representing a novel metabolic pathway.

     

Erythrocyte diagnostic agents for detecting bacterial antigens of the genus Citrobacter

Citrobacter antigenic and antibody erythrocyte diagnosticums, serogroups 1, 2, 3, 4, 5, 6, 7, 8, 11, 12, 13, and 22, have been developed. Tests with the use of these diagnosticums have proved to be highly sensitive and mainly group-specific. The antigen in the cellular form is best detected by means of the passive hemagglutination test and in the molecular form, by means of the neutralization test. The antibody-binding and agglutinating activities of strictly group-specific and cross-reacting O-antigenic determinants differ in their sensitivity to heating and to treatment with phenol. In the study of fecal samples taken from patients the above method for the detection of Citrobacter antigens has been shown to have high resolution.     

Monosaccharide composition of the lipopolysaccharides of bacteria of the genus Citrobacter

The authors studied antigens obtained by Grasset's method from 13 strains of Citrobacter of the International collection. The strains possessed O- and H-antigens whose behaviur in the electric field differed. All the strains under study were divided into two groups (by the number of serologically-active components of their O-antigens); representatives of the second group had no cathode O-antigen component. Chemical composition of specific lipopolysaccharides (LPS) obtained by Westphal's method was determined. Fourteen different sugars were revealed. The strains under study were referred to the known chemotypes. Strain 16/52 (8a, 8c) was for the first time studied in respect to the monosaccharide composition of specific LPS, and was referred to chemotype designated as CC-L.     

Frequency and antibiotic resistance of bacteria isolated from urine cultures]

The AA report the data pertinent to the urine culture performed during a year in the Sanitary and Prophylactic Laboratory of the district of L'Aquila. In urine samples with number of bacteria > 10(5)/ml have been found E. coli (49%), Proteus mirabilis (32%), Pseudomonas aeruginosa (12%), Staphylococcus aureus (5%), Proteus rettgeri (1%), Enterococco (1%). The data are also reported concerning germ resistance to several antibiotics.     

Transformation of various species of gram-negative bacteria belonging to 11 different genera by electroporation

Summary We have undertaken a systematic study to test the transformation of various species of gram-negative bacteria using the electroporation method. The data obtained show very clearly that a great variety of gram-negative bacteria — 15 different species belonging to 11 different genera — including freshly isolated wild-type strains can be transformed efficiently by use of the electric-field mediated transformation technique. These include species of the families Enterobacteriaceae, Pseudomonadaceae, Rhizobiaceae, photosynthetic bacteria and strains for which transformation could not be achieved, up to now, by other methods.     

The characteristics of amino acid catabolism in bacteria of the genus Citrobacter

The comparison of the occurrence of enzymes effecting the deamination of dicarbon, aromatic and oxyamino acids, as well as transamination enzymes, in Citrobacter bacteria and the activity levels of these enzymes was made. The constant sign of such bacteria was the presence of serine and threonine dehydratase activity. 92% of the strains showed the presence of phenylalanine deaminase. No tryptophan activity was established. 96-98% of Citrobacter strains possessed phenylalanine, tyrosine and tryptophan aminotransferases with alpha-ketoglutaric acid functioning as the acceptor of the amino group.     

Synthesis of tyrosine and 3,4-dihydroxyphenylalanine by bacteria Citrobacter freundii

Among facultative-anaerobic bacteria utilizing formic acid, a large number of strains having tyrosine phenol lyase were found. The enzyme can catalyze synthesis of tyrosine and 3,4-dihydroxy phenyl alanine (DOPA) from pyruvate, ammonium and, accordingly, phenol and pyrocatechol. These strains were identified as Citrobacter freundii. Cell suspensions of the most active strains synthesized up to 75 g/l tyrosine for 12 hr, up to 86 g/l tyrosine for 24 hr, and up to 29 g/l DOPA for 42 hr. A medium containing yeast autolysate grown on hydrocarbons can be recommended to produce cells having a high tyrosine phenol lyase activity.     

Two different primary oxidation mechanisms during biotransformation of thymol by gram-positive bacteria of the genera Nocardia and Mycobacterium

Thymol has antibacterial, antifungal, insecticidal, and antioxidative properties which are the basis for the wide use of this compound in the cosmetic, food, and pharmaceutical industries. Although thymol is a ubiquitously occurring substance in the environment, data about its degradation and detoxification by bacteria are sparse. Here, we show the existence of two different pathways for the biotransformation of thymol by Nocardia cyriacigeorgica and Mycobacterium neoaurum which were described for the first time for gram-positive bacteria. The first pathway starts with hydroxylation of thymol to thymohydroquinone (2-isopropyl-5-methylbenzene-1,4-diol) with subsequent oxidation to thymobenzoquinone (2-isopropyl-5-methyl-1,4-benzoquinone). The second pathway involves hydroxylation of the methyl group followed by oxidation to 3-hydroxy-4-isopropylbenzoic acid, possibly via the aldehyde 3-hydroxy-4-isopropylbenzaldehyde. It is noteworthy that the branched side chain of thymol was not oxidized. Similarities and differences of these oxidation processes with those of the gram-negative bacterium Pseudomonas putida, fungi, and plants are discussed and, in addition, the toxicity of thymol towards N. cyriacigeorgica and M. neoaurum was tested. The experiments showed a temporary growth inhibition with 0.025 % thymol. This was explained by degradation of thymol and the formation of products which are less toxic than thymol itself.     

Ladderane lipid distribution in four genera of anammox bacteria

Intact ladderane phospholipids and core lipids were studied in four species of anaerobic ammonium oxidizing (anammox) bacteria, each representing one of the four known genera. Each species of anammox bacteria contained C(18) and C(20) ladderane fatty acids with either 3 or 5 linearly condensed cyclobutane rings and a ladderane monoether containing a C(20) alkyl moiety with 3 cyclobutane rings. The presence of ladderane lipids in all four anammox species is consistent with their putative physiological role to provide a dense membrane around the anammoxosome, the postulated site of anammox catabolism. In contrast to the core lipids, large variations were observed in the distribution of ladderane phospholipids, i.e. different combinations of hydrophobic tail (ladderane, straight chain and methyl branched fatty acid) types attached to the glycerol backbone sn-1 position, in combination with different types of polar headgroup (phosphocholine, phosphoethanolamine or phosphoglycerol) attached to the sn-3 position. Intact ladderane lipids made up a high percentage of the lipid content in the cells of "Candidatus Kuenenia stuttgartiensis", suggesting that ladderane lipids are also present in membranes other than the anammoxosome. Finally, all four investigated species contained a C(27) hopanoid ketone and bacteriohopanetetrol, which, indicates that hopanoids are anaerobically synthesised by anammox bacteria.     

Terminal oxidases in different genera of the family Microbacteriaceae

The nature of terminal oxidases in representatives of four different genera of the family Microbacteriaceae was studied. It was found that the late-logarithmic and early-stationary cells of all of the investigated strains of the genera Plantibacter and Okibacterium contain the aa3-type cytochrome oxidase. Bacteria of the genera Rathayibacter and Agreia synthesize three oxidases, the bb3- and aa3-type cytochrome oxidases and nonheme cyanide-resistant oxidase, in proportions dependent on the cultivation conditions and the growth phase. Oxygen deficiency in the cultivation medium induces the synthesis of the bd-type oxidase in all of the microorganisms studied. The data obtained provide evidence that the type of terminal oxidases, along with the known chemotaxonomic characteristics, may serve to differentiate the genera of the family Microbacteriaceae at the phenotypic level.