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D G LUNDGREN

Publications and source records attributed to D G LUNDGREN.

16 recordsLinked to original sources
PubMed1965

MORPHOLOGICAL CHANGES IN POLY-BETA-HYDROXYBUTYRATE GRANULES ASSOCIATED WITH DECREASED SUSCEPTIBILITY TO ENZYMATIC HYDROLYSIS.

Merrick, J. M. (State University of New York, Buffalo), D. G. Lundgren, and R. M. Pfister. Morphological changes in poly-beta-hydroxybutyrate granules associated with decreased susceptibility to enzymatic hydrolysis. J. Bacteriol. 89:234-239. 1965.-A complex enzyme system obtained from extracts of Rhodospirillum rubrum cells hydrolyzes poly-beta-hydroxybutyric acid (PHB) contained in native PHB granules isolated from Bacillus megaterium. A labile factor associated with the granules and necessary for depolymerization is easily destroyed by various chemical and physical treatments. Granules inactivated by these treatments were examined in an electron microscope. In all cases, the distinct morphological appearance of native granules was altered. Morphological changes were mainly characterized by membrane fragmentation, loss of coalescence, and surface alterations. These observations suggest that native PHB granules possess definite structural features, disruption of which results in decreased susceptibility of the polymer to enzymatic hydrolysis.

Bacillus megaterium↗
PubMed1965

CHARACTERIZATION OF POLY-BETA-HYDROXYBUTYRATE EXTRACTED FROM DIFFERENT BACTERIA.

Lundgren, D. G. (Syracuse University, Syracuse, N.Y.), R. Alper, C. Schnaitman and R. H. Marchessault. Characterization of poly-beta-hydroxybutyrate extracted from different bacteria. J. Bacteriol. 89:245-251. 1965.-Poly-beta-hydroxybutyrate (PHB) from different bacterial genera was studied with regard to its crystal structure, infrared absorption, intrinsic viscosity, and electron microscopy. All PHB samples precipitated from dilute chloroform solution gave identical X-ray diffractograms confirming uniformity of crystal structure, and uniformity of molecular structure, based on the similarity of the recorded infrared spectra, was also established. Crystal morphology was also similar, showing the reported "lath" shape structure for purified polymer from Bacillus cereus. Intrinsic viscosity ranged from 0.04 to 11.5 depending upon the polymer treatment; polymer molecular weights, based upon viscometry, could be estimated to range from 1,000 to 250,000. It is concluded that the same basic molecule is involved in all PHB present in the bacterial kindgom.

Azotobacter↗
PubMed1965

ENERGY SUPPLY FOR THE CHEMOAUTOTROPH FERROBACILLUS FERROOXIDANS.

Dugan, Patrick R. (Syracuse University, Syracuse, N.Y.), and Donald G. Lundgren. Energy supply for the chemoautotroph Ferrobacillus ferrooxidans. J. Bacteriol. 89:825-834. 1965.-A working model is proposed to explain dissimilatory ferrous iron oxidation by Ferrobacillus ferrooxidans, that is, oxidation linked to an energy source. The model is supported by experimental evidence reported here as well as in the literature. Polarographic assays of the culture medium demonstrated an iron "complex" involving oxygen. The initial "complex" would be oxygenated, but not oxidized because no electron transport has taken place. The "complex" is formed in solution or on the cell surface and is somehow reacted with iron oxidase (or oxygenase), resulting in the release of an electron. Either sulfate or a flavoprotein is suggested as involved in the initial electron-transfer link between iron and the cell. The electron is transported in the cell through a typical electron-transport system involving coenzyme Q(6), cytochrome c, and cytochrome a; oxygen is the final electron acceptor. Electron micrographs of intact and sectioned cells are included to show structural detail in support of the model.

Acidithiobacillus↗
PubMed1964

ELECTRON MICROSCOPY OF POLYRIBOSOMES WITHIN BACILLUS CEREUS.

Pfister, R. M. (Syracuse University, Syracuse, N.Y.), and D. G. Lundgren. Electron microscopy of polyribosomes within Bacillus cereus. J. Bacteriol. 88:1119-1129. 1964.-Clusters of ribosomes (polyribosomes) were identified in thin sections of Bacillus cereus. Cells were treated by freezing and thawing to induce partial lysis to permit a closer examination of structural detail. The polyribosomes were (at times) attached to the cytoplasmic membrane, and ribosome clusters contained about 10 to 55 individual ribosomes. Individual ribosomes ranged from 70 to 100 A, whereas polyribosomes were about 150 to 850 A wide. A membrane served as the fabric holding the ribosomes, which were about 50 to 100 A apart.

Bacillus cereus↗
PubMed1963

GROWTH AND SPORULATION CHARACTERISTICS OF AN ORGANIC SULFUR-REQUIRING AUXOTROPH OF BACILLUS CEREUS.

Lundgren, D. G. (Syracuse University, Syracuse, N.Y.) and K. F. Bott. Growth and sporulation characteristics of an organic sulfur-requiring auxotroph of Bacillus cereus. J. Bacteriol. 86:462-472. 1963.-This paper reports investigations of several aspects of growth and sporulation of an organic sulfur-requiring auxotroph of Bacillus cereus ATCC 4342. The wild type and B. cereus T were also studied for comparative purposes. Growth of the mutant on minimal medium plus methionine was normal, but sporulation was completely inhibited. Some reaction involved in vegetative-cell maturity was probably blocked at a point just prior to the "triggering" of sporulation, since abnormally large amounts of poly-beta-hydroxybutyric acid (PHB) were formed. Growth of the mutant in the presence of cystine or cysteine was also accompanied by the build-up of large amounts of PHB, but some endospores were formed (approximately 5% by 72 hr). Results of dipicolinic acid (DPA), calcium, and heat-resistance studies revealed that the few spores formed by the auxotrophic mutant when grown on cysteine were somewhat below wild-type strains in their development of heat resistance, and considerably lower in content of Ca and DPA. This was not the case with spores formed in cells grown on cystine; heat resistance compared favorably with wild-type spores, but the Ca and DPA levels were lower.

Bacillus cereus↗
PubMed1962

Chemical analyses of asporogenic mutants of Bacillus cereus.

Lundgren, D. G. (Syracuse University, Syracuse, N.Y.) and J. J. Cooney. Chemical analyses of asporogenic mutants of Bacillus cereus. J. Bacteriol. 83:1287-1293. 1962.-Bacillus cereus ATCC 4342 and three temperature-sensitive asporogenic mutants were compared regarding some basic cellular components and response to metals in a synthetic medium. The mutants sporulate when cultured at 28 C but are asporogenic when cultured at 37 C; the parent sporulates at both temperatures. Results of amino acid analyses of cells harvested at characteristic times during the culture cycle revealed no qualitative differences which could be related to the asporogenic nature of the mutants. All sporulating cultures synthesized dipicolinic acid during sporulation, but asporogenic cultures did not. The patterns of zinc, potassium, sodium, and calcium uptake, but not of iron or manganese uptake, appear to be affected in the asporogenic mutants.

Bacillus↗