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D G Lundgren

Publications and source records attributed to D G Lundgren.

33 records · Page 2Linked to original sources
PubMed1968

Peptidoglycan of a chemolithotrophic bacterium, Ferrobacillus ferrooxidans.

The rigid layer (peptidoglycan) of the wall of the chemolithotroph Ferrobacillus ferrooxidans was isolated after various chemical treatments. The removal of specific components was followed by noting in an electron microscope changes in the appearance of the cell surface. The final peptidoglycan was virtually free from proteins and was sensitive to the action of lysozyme. Results of chemical analyses of acidhydrolyzed peptidoglycan revealed three major amino acids and two amino sugars: glutamic acid, alpha,epsilon-diaminopimelic acid, alanine, glucosamine, and muramic acid in a ratio of 1:1:2.33:062:088.

Alanine↗
PubMed1967

Effect of glucose on carbon dioxide assimilation and substrate oxidation by Ferrobacillus ferrooxidans.

Ferrobacillus ferrooxidans, grown on either elemental sulfur or ferrous sulfate, was able to use either substrate as an energy source for the assimilation of CO(2). In both cases, 0.01 mumole of carbon was incorporated per mumole of oxygen utilized. Glucose inhibited substrate oxidation and CO(2) fixation. Sulfur and iron oxidation were inhibited 5 to 15% and 40 to 50%, respectively, in the presence of 10% glucose. Under the same conditions, CO(2) assimilation was inhibited 50% with elemental sulfur as the energy source, and was almost totally inhibited when ferrous iron was used.

Bacteria↗
PubMed1967

Fine structure of Bacillus megaterium during synchronous growth.

A fine-structure study of synchronously dividing Bacillus megaterium revealed the sequence of events involved in the division of the cell. First, a mesosome develops as a concentric fold of the plasma membrane at the site of septum formation. The mesosome contains membrane-bound vesicular structures, 300 to 500 A in diameter, plus a large membrane-bound structure, 2,000 A in diameter. These larger vesicles are peculiar to mesosomes in this stage of division and are not observed in the mesosomes involved in spore septum formation. The transverse septum originates within the mesosome and remains enclosed during its subsequent growth across the cell. An intimate association is observed between mesosome vesicles, mesosome membrane, and the growing edge of the transverse septum. Prior to completion of the septum, the membranes bounding the mesosome fuse, and further wall thickening occurs within the structure formed by this fusion. At this time, the septum only equals the parent cell wall in thickness. The doubling in thickness of the septum, which is required for the production of two normal daughter cell walls, occurs during a second phase of wall thickening, which is characterized by the appearance of a constriction at the base of the septum. As the constriction widens, the wall in this region thickens, forming the typical rounded poles of the daughter cells. Capsular synthesis at the poles occurs during this second phase of wall thickening. Throughout the division process, the nuclear material appears to be associated at one end with a mesosome at or near the pole of the cell and at the other end to the mesosome involved in septum formation. This association frequently takes the form of a stalklike extension of the mesosome penetrating into the chromatin fibrils.

Bacillus megaterium↗
PubMed1966

Inhibition of the development of the spore septum and membranes in Bacillus cereus by beta-phenethyl alcohol.

Remsen, C. C. (Syracuse University, Syracuse, N.Y.), D. G. Lundgren, and R. A. Slepecky. Inhibition of the development of the spore septum and membranes in Bacillus cereus by beta-phenethyl alcohol. J. Bacteriol. 91:324-331. 1966.-The effect of phenethyl alcohol (PEA) upon the initial stages of sporulation in Bacillus cereus was studied with an electron microscope. PEA (0.35%) completely inhibited the development of the spore septum and forespore membranes. Some of the treated cells did form the axial filament of chromatin material regarded as the first stage in sporulation, but this was delayed by 4 to 5 hr compared with untreated cells. The definite effect upon these membrane systems lends support to the belief that the primary site of PEA inhibition may be upon the bacterial membrane. The fine-structure details observed during the initial stages of sporulation in untreated cells were in agreement with the structure published for other Bacillus species.

Alcohols↗
PubMed1966

Physiology of growth and sporulation in Bacillus cereus. I. Effect of glutamic and other amino acids.

Buono, F. (Syracuse University, Syracuse, N.Y.), R. Testa, and D. G. Lundgren. Physiology of growth and sporulation in Bacillus cereus. I. Effect of glutamic and other amino acids. J. Bacteriol. 91:2291-2299. 1966.-Growth and sporulation were studied in Bacillus cereus by use of an active culture technique and a synthetic medium. A high level of glutamic acid (70 mm) was required for optimal growth and glucose oxidation followed by sporulation even though relatively little glutamic acid was consumed (14 mm). Optimal growth occurred with a combination of 14 mm glutamic acid and 56 mm (NH(4))(2)SO(4), aspartic acid, or alanine. Ornithine or arginine at 70 mm could replace glutamic acid in the synthetic medium without affecting the normal growth cycle. Glutamic acid was not replaced by any other amino acid, by (NH(4))(2)SO(4), or by a combination of either alpha-ketoglutarate or pyruvate plus (NH(4))(2)SO(4). Enzyme assays of cell-free extracts prepared from cells harvested at different times were used to study the metabolism of glutamic acid. Glutamic-oxaloacetic and glutamic-pyruvate transaminases were completely activated (or derepressed) during early stages of sporulation (period of 6 to 8 hr). Alanine dehydrogenase responded in a similar manner, but the levels of this enzyme were much higher throughout the culture cycle. Neither glutamic dehydrogenase nor alpha-ketoglutarate dehydrogenase was detected. Sporulation in a replacement salts medium was studied with cells harvested at different times from the synthetic medium. Cultures 2 to 6 hr old were unable to sporulate in the replacement salts medium unless glutamic acid (7.0 mm) was present. By the 6th hr, cells were in the early stages of sporulation, showing spore septa development. Cultures 8 hr old sporulated in the replacement salts medium. Other metabolic intermediates able to replace glutamic acid in the replacement salts medium were alanine, aspartic acid, and glutamine at equimolar concentrations. Also, ammonium ions in combination with pyruvic, oxaloacetic, alpha-ketoglutaric, or fumaric acid replaced glutamic acid. The likely role of these metabolites is discussed.

Alanine↗
PubMed1966

Sulfur oxidation by the iron bacterium Ferrobacillus ferrooxidans.

Margalith, P. (Syracuse University, Syracuse, N.Y.), Marvin Silver, and D. G. Lundgren. Sulfur oxidation by the iron bacterium Ferrobacillus ferrooxidans. J. Bacteriol. 92:1706-1709. 1966.-Sulfur and iron oxidation has been studied manometrically by use of Ferrobacillus ferrooxidans grown on either elemental sulfur or ferrous iron as the primary energy source. The iron-oxidizing enzyme was shown to be constitutive, since iron was oxidized as rapidly by sulfur-grown cells as by iron-grown cells. Sulfur-grown cells had a better capacity for oxidizing sulfur than did iron-grown cells; however, no lag in oxidation was seen in either case. The sulfur-oxidizing system was not inducible, and it is suggested that the different oxidative capacities are due to the heterogeneous mixture of cell types in the culture population.

Bacteria↗
PubMed1966

Fine structure of sporulation in Bacillus cereus grown in a chemically defined medium.

Ellar, D. J. (Syracuse University, Syracuse, N.Y.), and D. G. Lundgren. Fine structure of sporulation in Bacillus cereus grown in a chemically defined medium. J. Bacteriol. 92:1748-1764. 1966.-A study was made of the fine structure of sporulating cells of Bacillus cereus grown in a chemically defined medium. The developmental stages of sporulation occurred in a fairly synchronous manner and were complete by 14 hr. This time period was shortened when spore wall peptide components were added to the medium, but the addition had no effect upon fine structure except to thicken the cell wall. Sporulation could be separated into six morphological stages which generally agreed with those published for other sporulating bacteria. The initiation of the spore (forespore) septum takes the form of an inward folding of the cytoplasmic membrane toward the pole of the cell. The inward folding forms a characteristic Y-shaped membrane structure enclosing an area within which vesicles are found. These vesicles comprise the perisporal mesosome of the cell. The membranes on opposite sides of the cell progress toward the cell center where they fuse to form the double unit membrane of the spore septum. As the proliferation of the spore septum continues, the vesicular areas move towards the pole. The end result is a double forespore membrane which completely encloses a part of the vegetative cell's chromatin. Sporal mesosomes, as well as membrane vesicles, are involved in the proliferation of the forespore. Vesicles are generally bounded by a single unit membrane, whereas in the sporal mesosomes several unit membranes are arranged concentrically. The latter become associated with the segregation of a portion of the nuclear material into the forespore region of the cell.

Bacillus cereus↗
PubMed1966

Electron microscopy of the cell envelope of Ferrobacillus ferrooxidans prepared by freeze-etching and chemical fixation techniques.

Remsen, C. C. (Swiss Federation Institute of Technology, Zurich, Switzerland), and D. G. Lundgren. Electron microscopy of the cell envelope of Ferrobacillus ferrooxidans prepared by freeze-etching and chemical fixation techniques. J. Bacteriol. 92:1765-1771. 1966.-A comparison was made of the fine structure of the cell envelope of the gram-negative bacterium Ferrobacillus ferrooxidans when cells were prepared for microscopy by freeze-etching and chemical fixation techniques. Cell envelopes of chemically fixed cells appeared as five separate layers distinguishable by their location and electron density. Frozen-etched cells showed a three-layered complex with each layer measuring approximately 100 A in thickness. The latter technique is considered to be "artifact-free" and, as a technique, yields purely morphological information on the natural state. The three layers revealed by freeze-etching are: the outer layer, a lipoprotein-lipopolysaccharide layer; the middle layer, a layer composed of globular protein attached to fibrillar mucopeptide; and the innermost layer, the cytoplasmic membrane. The latter was covered with 100 to 120 A particles. The relationship of the aforementioned layers to those seen in chemically fixed cells is discussed.

Bacteria↗
PubMed1965

Multiple septation in variants of Bacillus cereus.

Remsen, C. C. (Syracuse University, Syracuse, N.Y.), and D. G. Lundgren. Multiple septation in variants of Bacillus cereus. J. Bacteriol. 90:1426-1431. 1965.-Abnormal nonsporulating cells observed in cultures containing predominantly endospores were examined in an electron microscope. One or more septa were seen which consisted of cell-wall material between two unit membranes. Numerous membrane swirls were often seen associated with the septa. Some of the reported structural features of the variant cells were similar to those published for Bacillus cereus var. alesti and B. subtilis; however, the majority of the cells observed in this work were multiseptated.

Bacillus cereus↗