Production of antibody against conjugated dipicolinic acid (2,6 pyridine dicarboxylic acid)

An immunological precipitation system, with rabbit dipicolinyl antibody, was developed for the purpose of evaluating the role of spore dipicolinic acid as a specific haptenic determinant.

CHANGES IN THERMORESISTANCE OF CLOSTRIDIUM ROSEUM AS RELATED TO THE INTRACELLULAR CONTENT OF CALCIUM AND DIPICOLINIC ACID

The cellular content of calcium and dipicolinic acid was determined quantitatively throughout the sporulation and germination processes of Clostridium, roseum. Cell counts were made throughout both processes to relate the changes in the thermoresistant population with the changes in cellular calcium and DPA. Calcium accumulation and DPA biosynthesis occurred early in sporogenesis and preceded the transition of the vegetative cells to thermoresistant spores. Calcium accumulation preceded both DPA biosynthesis and thermoresistance. During germination 80% of the cells became thermosensitive within 15 minutes after heat shock; however, the loss of calcium and DPA from the cells proceeded at a much slower rate. Approximately 2 hours of incubation were required for completion of the germination transition and the onset of cell division.

RESPONSES OF BACILLUS SUBTILIS SPORES TO IONIC ENVIRONMENTS DURING SPORULATION AND GERMINATION

Fleming , H. P. (University of Illinois, Urbana), and Z. John Ordal . Responses of Bacillus subtilis spores to ionic environments during sporulation and germination. J. Bacteriol. 88: 1529–1537. 1964.—The ionic environments of germination and sporulation menstrua had a prominent influence on characteristics of Bacillus subtilis spores. There was a synergistic effect for l -alanine and inorganic ions on spore germination. The maximal rate of germination in solutions of l -alanine was dependent on ionic concentration and species. Germination was negligible in l -alanine at low ionic strength but increased as the ionic strength was increased up to about 10 −1 m with a variety of salts. Phosphate was the most active ion tested, and divalent cations were the least active in supporting germination in l -alanine. Germination progressed slowly at 45 C in sodium chloride or sodium phosphate alone but not in CaCl 2 alone. Germination rates in l -alanine were retarded at high ionic strengths (μ in the range of 0.1 to 1.0). Inhibitory effects of high concentrations of certain divalent cations on germination were related to the binding abilities of these metals. High concentrations of NaCl (10 −1 to 1.0 m ) in the sporulation medium resulted in lowered heat resistance and germination rate of the resulting spores. The addition of calcium (5 × 10 −2 m CaCl 2 ) to the sporulation medium relieved the repression of NaCl on germination and caused the spores to have a greater heat resistance. Calcium and dipicolinic acid (DPA) contents of the spores were unaffected by NaCl in the sporulation medium. The calcium, but not the DPA, content of spores increased as a result of supplementing the sporulation medium with calcium. Possible roles of ions in the germination of spores are discussed.

CHARACTERISTICS OF AN ABORTIVELY DISPORIC VARIANT OF BACILLUS CEREUS

Young, I. Elizabeth (University of Alberta, Edmonton, Alberta, Canada). Characteristics of an abortively disporic variant of Bacillus cereus. J. Bacteriol. 88:242-254. 1964.-A variant [A(-)3] of the Bacillus cereus group has been isolated which appears to begin the formation of a spore at each pole of the cell. These pseudo-forespores, like conventional forespores, are initially formed by invagination of the plasma membrane. However, their maturation does not continue the course of normal spore development. There is no further proliferation of the membrane and no development of the peripheral layers, the cortex, spore coat, or exosporium; there is deposition of apparent cell-wall material between the layers of the septa. Each pseudo-forespore receives approximately one-half of the cell's chromatin. With a supply of fresh nutrients, each is able to resume division after elongation to the bacillary form. Furthermore, the portion of the cell lying between the two pseudo-forespores, containing at most a fragment of the total chromatin, is able to resume growth and division. This growth potential has been interpreted as evidence that the chromatin body of the variant contains more than one set of the genetic instructions characteristic of the organism. A single growth cycle in the presence of dipicolinic acid (thought to cure some Bacillus species of phage) results in approximately 40% of the cells producing a single spore. These spores resemble those formed by the organism from which A(-)3 was isolated. The possibility that the abortively disporic state is associated with the presence of an infecting phage is discussed.

BIOCHEMICAL CHANGES OCCURRING DURING SPORULATION OF BACILLUS CEREUS T II

Gollakota , K. G. (University of Illinois, Urbana) and H. Orin Halvorson . Biochemical changes occurring during sporulation of Bacillus cereus T. II. Effect of esters of organic acids on sporulation. J. Bacteriol. 85: 1386–1393. 1963.—Sporulation of Bacillus cereus T in yeast extract-glucose-minerals medium was specifically inhibited by α-picolinic acid (APA), if the acid was added before the pH of the culture began to rise. The effects of APA could be reversed by aspartic acid or asparagine, among the amino acids, and by intermediates of the tricarboxylic acid cycle, with the exception of α-ketoglutarate and fumarate. Formate, malonate, and certain other organic acids also possessed this ability. Succinate was the best reversing agent. Fluoroacetic acid (FAA) also inhibited sporulation, but had no effect on vegetative growth or germination of spores of B. cereus T. Unlike APA, FAA inhibited sporulation even when added after the pH of the culture had started to rise. Bisulfite was similar to FAA in its effects on sporulation. With the exception of pyruvate, acetate, aspartate, and malate, most of the compounds reversing the effects of APA also overcame the effects of FAA or bisulfite on sporulation. Esters of some of the acids reversing the effects of the above inhibitors were studied for their action on germination, growth, and sporulation. Ethyl pyruvate prevented germination of the spores, slowed down growth, and inhibited sporulation. Ethyl malonate and ethyl succinate inhibited only sporulation. All the above inhibitors prevented the synthesis of dipicolinic acid (DPA) also. When B. cereus T was grown in the absence of glucose (in extracted yeast extract-minerals medium), the above inhibitors had no effect on sporulation. Ethyl oxamate permitted sporulation, but the spores produced were heat-sensitive. Ethyl pimelate caused lysis when added before the pH of the culture began to rise. When added after the pH of the culture began to rise, it also permitted sporulation, and the spores were sensitive to heat. (These heat-sensitive spores were refractile and dormant, and did not stain with crystal violet. However, they germinated normally, losing refractibility and became stainable.) The effect of ethyl oxamate and ethyl pimelate could be overcome by DPA. APA, FAA, ethyl malonate, and ethyl succinate also inhibit the sporulation of a number of other bacilli.

BACTERIAL OXIDATION OF DIPICOLINIC ACID

Kobayashi, Yasuo (University of Tokyo, Tokyo, Japan) and Kei Arima . Bacterial oxidation of dipicolinic acid. II. Identification of α-ketoglutaric acid and 3-hydroxydipicolinic acid and some properties of cell-free extracts. J. Bacteriol. 84: 765–771. 1962—When a dipicolinic acid (DPA)-decomposing bacterium, Achromobacter strain 1–2, was incubated at 30 C with shaking in a DPA solution containing 10 −3 m arsenite, a keto acid was accumulated. The 2,4-dinitrophenylhydrazone of this acid was synthesized and identified as α-ketoglutaric acid by paper chromatography, visible absorption spectrum, infrared analysis, elemental analysis, and mixed melting point. During this incubation, oxalic acid equivalent to the consumed dipicolinic acid was produced. A fluorescent material was also isolated from culture fluid and identified as 3-hydroxydipicolinic acid by paper chromatography and the ultraviolet absorption spectrum. Further, cell-free extracts were prepared by sonic oscillation. Ferrous ion and a reduced di- or triphosphopyridine nucleotide-generating system were proven to be required for enzymic oxidation of DPA. And 3-hydroxydipicolinic acid was also oxidized by this preparation. From the results obtained, a possible metabolic pathway of dipicolinic acid was proposed.