An Initial Approach to the Taxonomy of Some Gram Negative Yellow Pigmented Rods

SUMMARY: The responses of various groups of Gram negative, yellow pigmented rods constructed on the basis of classical criteria to a wide range of cultural and biochemical features were examined. The occurrence of a wide area of slime surrounding true growth with isolates which may spread but did not glide is described. The correlation between the classical groups and divisions suggested on the basis of pigment absorption curves was examined.     

A Taxonomic Study of Flavobacteria and Related Gram Negative Yellow Pigmented Rods

One hundred and seventy-nine yellow pigmented Gram negative rods, including 170 new isolates obtained from a variety of habitats, were investigated and the results analysed by computer. Nine phena, embracing 146 strains, were distinguished. Five of these comprised 88 of the 109 non-motile, aflagellate strains (i.e. 'atypical cytophagas') and they should be assigned to a re-defined genus Flavobacterium . A separate phenon containing 41 of the gliding isolates was delineated which should be ascribed provisionally to the genus Flexibacter . Only low G + C contents have been recorded for representative strains from these six phena but one strain (which would have been ascribed to Flavobacterium ) had a high G + C content; such organisms (both peritrichous and non-motile) should comprise a separate genus Empedobacter (Brisou). The remaining three phena respectively comprised strains of Erwinia herbicola , pseudomonads and unclassified aflagellate isolates; their taxonomic position is discussed.     

Deoxyribonucleic Acid Base Composition of Flavobacteria and Related Gram Negative Yellow Pigmented Rods

DNA base composition analyses on 35 Gram negative yellow pigmented rods indicated two distinct groups. The larger contained 29 strains with G + C contents of between 30·8 and 39·5% and comprise 19 non-gliding, aflagellate strains and 10 gliding strains. The smaller, a heterogenous collection of six strains, had G + C contents in the 51·4–63% range.     

The Adansonian Taxonomy and the Deoxyribonucleic Acid Base Composition of some Gram Negative, Yellow Pigmented Rods

S ummary : The numerical taxonomy technique of Sneath (1957) was used to differentiate types of Gram negative, yellow pigmented rods isolated from food products. DNA base ratios were determined for representative isolates from each of the major groups formed. A determinative scheme using features extracted from the data has been suggested. The problems of nomenclature of organisms of this type are discussed.     

Identity of Gram Negative, Yellow Pigmented, Fermentative Bacteria isolated from Plants and Animals

S ummary . Morphological, cultural and biochemical properties of 35 isolates of rod shaped Gram negative, yellow pigmented anaerogenic, fermentative bacteria were compared. The isolates comprised named cultures of Bacterium herbicola, Erwinia lathyri, E. ananas, E. milletiae, E. uredovora and B. typhi flavum , as well as organisms isolated from deer and man which were considered to be related to E. milletiae. The results showed that the organisms were indistinguishable from one another on the basis of the tests employed, and it is concluded that B. herbicola, B. typhi flavum, E. lathyri and E. ananas should be classified as Erwinia herbicola (Düggeli) Dye. Since there was insufficient information regarding the plant pathogenicity of E. milletiae and E. uredovora , it is suggested that they should remain separate species at present. The relationship of this group of organisms to certain coliforms and to flavobacteria is briefly discussed.     

The Hydrolysis of Dextran by Gram Negative Non-sporing Anaerobic Bacilli

The ability of Gram negative anaerobic bacilli to hydrolyse dextran was determined in liquid and solid media containing Blue Dextran 2000. Released blue chromophore in the liquid medium was detected spectrophotometrically. Results obtained with 334 strains of Bacteroidaceae grown on the solid medium indicated that most strains did not hydrolyse the substrate. Hydrolysis of Blue Dextran 2000 occurred with certain strains of Bacteroides thetaiotaomicron , B. melaninogenicus ss. melaninogenicus, B. oralis, B. ovatus and B. ochraceus.     

The Characterization of Clinically Important Gram Negative Anaerobic Bacilli by Conventional Bacteriological Tests

One hundred and sixty-five reference strains and laboratory isolates of Gram negative, non-sporing, anaerobic bacilli were subjected to a series of simple laboratory tests that were initially selected for their discriminatory value. Conventional biochemical tests, tests of resistance to antibiotics, and tolerance to dyes and bile salts were included. These tests allowed a clear separation of strains into three main groups: Bacteroides fragilis, B. melaninogenicus and Fusobacterium spp. Certain tests were found useful for identifying recognized subspecies of B. fragilis and B. melaninogenicus . A scheme for the identification of unknown laboratory isolates of Gram negative anaerobic bacilli is presented.     

(Symposium on Myxobacteria and Flavobacteria: Paper X). Properties of Some Pectolytic, Yellow pigmented, Gram Negative Bacteria Isolated from Fresh Cauliflowers

Pectolytic, yellow-pigmented, Gram negative bacteria formed 3·3% of the organisms isolated at 23° from fresh cauliflowers, and may contribute to deterioration of this vegetable in storage. The bacteria attacked glucose oxidatively in the Hugh & Leifson (1953) test, were nonmotile and oxidase-positive, conforming to definitions of the genus Flavobacterium. These strains showed differences in morphological and physiological properties from F. pectinovorum NCIB 9059, which has properties resembling those of Cytophaga spp.     

Computer-aided Numerical Identification of Gram negative Fermentative Rods on a Desk-top Computer

One hundred and sixty-three strains of Gram negative fermentative rods isolated from humans and 60 isolated from diseased snails were identified by a conventional method and by numerical identification on a desk-top computer. The two methods gave the same identities with 133 'human strains' and 33 'snail strains'. The possible sources of the differences in identifications are discussed. The study showed that numerical identification done on a desk-top computer can be a useful method for routine medical microbiological laboratories.     

Phloem Loading and Metabolism of Xylem-Borne Amino Compounds in Fruiting Shoots of a Legume

Cut, fruiting shoots of Lupinus albus L. supplied with ¹⁴C-and ¹⁵N-labelled L-asparagine, L-glutamine, L-aspartic acid,or L-glutamic acid through the transpiration stream readilytransferred the labelled carbon and nitrogen of each compoundto pods and seeds of fruits. A time course of labelling of phloemsap collected from petioles and fruit tips following feedingof labelled asparagine indicated that xylem to phloem exchangein leaflets was an immediate and effective route of transferof the amide to fruits and that this and the loading onto phloemof additional asparagine from unlabelled pools of the amidein stems furnished a major source of the nitrogen for fruitfilling. Xylem to phloem exchange of nitrogen was accomplishedin different ways for each amino acid. The amide nitrogen ofasparagine was transferred mainly in the unmetabolized compound,the nitrogen of aspartate and glutamate largely in a wide rangeof amino acids synthesized in the leaf, and the amide nitrogenof glutamine was transferred in a manner intermediate betweenthese extremes. Glutamine and asparagine were the principalphloem solutes labelled with nitrogen from any of the suppliedcompounds, but the photosynthetically produced amino acids,glutamate, aspartate, serine, alanine, and valine also became¹⁵N-labelled in phloem. The main pathway for glutamine synthesisin vegetative parts of the shoot appeared to be by amidationof glutamate, but asparagine was not considered to be derivedsimilarly from aspartate. Leaflets metabolized glutamine morereadily than asparagine, but in each case the amide nitrogenwas used for synthesis of a variety of amino acids and the carbonwas recovered largely in non-amino compounds.     

Metabolism of Pyridine Compounds by Phthalate-Degrading Bacteria

Bacteria were isolated from marine sediments that grew aerobically on m-phthalate, p-phthalate, or dipicolinate (2,6-pyridine dicarboxylate [2,6-PDCA]). Strain OP-1, which grew on o-phthalate and was previously obtained from a marine source, was also studied. Intact cells of each organism demonstrated Na⁺-dependent oxidation of their growth substrates. Strain PCC5M grew on dipicolinate but did not metabolize m-phthalate. The phthalate degraders, however, demonstrated Na⁺-dependent metabolism of the appropriate PDCA analogs. 2,6-PDCA was transformed by strain CC9M when this strain was grown on m-phthalate, 2,5-PDCA was metabolized by strain PP-1 grown on p-phthalate, and 2,3-PDCA (quinolinate) was oxidized by strain OP-1 grown on o-phthalate. Spectral changes accompanying the Na⁺-dependent transformations of the PDCA analogs suggest the formation of hydroxylated compounds. Metabolism probably occurred via phthalate hydroxylases; this is a previously unrecognized route for the environmental transformation of pyridine compounds. Hydroxylated products may feed into known pathways for the catabolism of pyridines or be photochemically degraded because of their absorbance in the solar actinic range (wavelengths > 300 nm). The results reinforce recent evidence for the broad potential of aromatic hydroxylase systems for the destruction of pollutants.     

氨基酸酰胺类化合物的合成

阐述了氨基酸氨基保护的常用方法和试剂,氨基酸酰胺类化合物合成的基本原理和方法以及在合成中需要注意的问题。重点阐述了氨基酸酰胺类化合物的合成机理和合成方法。展望了氨基酸酰胺类衍生物的合成方向。     

Comparative Distribution and Metabolism of Xylem-Borne Amino Compounds and Sucrose in Shoots of Populus deltoides

The transport and metabolism of xylem-borne amino compounds and sucrose were investigated in rapidly growing shoots of cottonwood (Populus deltoides Bartr. ex Marsh.). ¹⁴C-labeled glutamine, threonine, alanine, glutamic acid, aspartic acid, and sucrose were applied to the base of severed stems for transport in xylem. Distribution and metabolism of the compounds were followed with autoradiography, microautoradiography, and radioassay. Three utilization patterns were observed: (a) little alanine and sucrose was transported to the laminae of either mature leaves or developing leaves. These compounds were taken up from xylem free-space and utilized in adjacent tissue; (b) threonine also did not move into mature leaves but was translocated to developing leaves or utilized in the stem; (c) glutamic acid and aspartic acid were transported directly into the laminae of mature leaves via the xylem. Relatively less ¹⁴C was retained in stems compared to the other compounds.

Metabolism of the test compounds also differed considerably. ¹⁴C from amino acids moved primarily into organic acids and protein. The ¹⁴C from sucrose was widely distributed among the chemical fractions, with a high percentage found in structural carbohydrates. Clearly, cottonwood stems contain efficient uptake and transfer systems that differentiate among various compounds moving from root to shoot in xylem.

     

Some Morphological and Physiological Characteristics of Gram Negative Anaerobic Bacteria isolated from the Alimentary Tract of the Pig

S ummary . A collection of 100 strains of Gram negative anaerobic bacteria isolated from the alimentary tract of the pig has been divided into four groups on morphological and physiological grounds. The four groups resemble the genera Bacteroides, Sphaerophorus, Veillonella and Peptostreptococcus as described in Bergey's Manual (Breed, Murray & Smith, 1957).     

Pigmented Bacteriostatic Substances and Amino Acids Produced by Phlebopus sulphureus and Phlebopus lignicola

The pigmented bacteriostatic substances and ninhydrin-reactive compounds produced in culture by sporophores, stipes, and residual medium of Phlebopus sulphureus and P. lignicola were studied chromatographically. Acetone extracts of both species demonstrated bacteriostatic activity against Bacillus subtilis and Escherichia coli, the maximal inhibition zone being 13 mm. The chloroform extract was inactive. Six compounds, mainly yellow, extracted in ethyl alcohol and separated by chromatography, were common to the sporophore of P. sulphureus and the stipes of P. lignicola. Eight amino acids, mainly sulfur-containing, were identified chiefly from the mature sporophore of P. sulphureus.     

Differentiation of Gram Positive and Gram Negative Bacteria in Transparent Acrylic Resin Emulsion Replicas of Surfaces of Plants

When acrylic resin emulsion (Rohm & Haas Primal AC-33) is allowed to dry on a leaf surface, it can be peeled off to give a transparent replica of the surface with bacteria and fungi embedded in it. The distribution of micro-organisms in the replica appears to reflect the patterns in which they occur naturally on the surface. The resin replicas may be stained by a variety of microscopical stains, the best of which is phenol-acetic-aniline blue, and are suitable for high power light microscopy.
Acrylic resin emulsion differs from widely used cellulose-based materials in that permanent differentiated preparations of Gram positive and Gram negative stained bacteria may be produced from a wide variety of types of surface.