COMPARISON OF SPECIES AND VARIETIES OF THE GENUS BACILLUS

Fowler's bacillus is one of several organisms which form a non-viable inclusion or parasporal body during the process of sporulation. This body is globular and may be as large as or larger than the spore. Its position in the cell is not random; the spore is terminal and the body paracentral, lying between the spore and the remaining vegetative cell chromatin bodies. On completion of sporulation both spore and body are contained within an exosporium. The sequence in the development of the cell structures was followed in ultrathin sections of material fixed in permanganate. When sporulation is well advanced the body begins to grow from a single crystal, then presumably as a result of some disorientation in the growth process it develops as a multicrystalline body with the lattices orientated at different angles. When the body approximates the spore in size, a lamella coat is formed and an exosporium develops which eventually encircles the body and the spore. Other lamella systems microscopically similar to those surrounding the parasporal body develop free in the cytoplasm outside the exosporium. In both of these systems the number of lamellae is variable. The spore coat of Fowler's bacillus, consisting of an outer lamella layer and an inner unresolved amorphous layer has been found microscopically identical to the spore coat of B. cereus. In both organisms the lamella layer of the spore coat consists, in contrast to the other lamella systems, of a regular number of lamellae. Physiological tests would indicate that Fowler's bacillus is a variety of B. cereus.

Section: Figure 1~supporting

confidence: 72%

Fowler's Bacillus and Its Parasporal Body

Hannay¹

1961

“…alesti were the organisms studied. Their origins and characteristics have been described previously (6).…”

Section: Culturing Techniquesmentioning

confidence: 99%

“…T h e procedures involved in the use of the light rations contrast was a u g m e n t e d by staining the cut sections with lead hydroxide by the m e t h o d of Watson (22) or Dalton and Zeigal (4); in others partial staining of the spore cortex was achieved by floating sections on phosphotungstic acid solution (1 per cent) and rinsing with water (14). Further details of the methods used in electron microscopy have been described (6).…”

Section: Microscopy and Cytological Techniquesmentioning

confidence: 99%

Chemical and Morphological Studies of Bacterial Spore Formation

Young

Fitz-James

1962

Self Cite

From the stage of a completed membranous forespore to that of a fully ripened free spore, synchronously sporulating cells of a variant Bacillus cereus were studied by cytological and chemical methods. Particular attention was paid to the development of the three spore layers--cortex, coat, and exosporium--in relation to the forespore membrane. First, the cortex is laid down between the recently described (5) double layers of the forespore membrane. Then when the cortex is 1/~ fully formed, the spore coat and exosporium are laid down peripheral to the outer membrane layer covering the cortex. As these latter layers appear, the spores, previously dense by dark phase contrast, gradually "whiten" or show an increase in refractive index. With this whitening, calcium uptake commences, closely followed by the synthesis of dipicolinic acid and the process is terminated, an hour later, with the formation of a fully refractile spore. In calcium-deficient media, final refractility is lessened and dipicolinic acid is formed only in amounts proportional to the available calcium. If calcium is withheld during the period of uptake beyond a critical point, sporulating cells lose the ability to assimilate calcium and to form normal amounts of dipicolinic acid. The resulting deficient spores are liberated from the sporangia but are unstable in water suspensions. Unlike ripe spores, they do not react violently to acid hydrolysis and, in thin sections, their cytoplasmic granules continue to stain with lead solutions.

“…alesli contains an average of 3.95 X 10 .9 ttg. DNA-phosphorus (DNA-P) while the spore contains 2.08 X 10 .9 #g. As the spore contains one chromatin body and' the actively growing vegetative cell two chromatin bodies (in some stage of division), this increased amount of DNA in relation to that in B. cereus represents an increased amount of nucleic acid per chromatin body rather than an increased number of chromatin bodies per cell (9).…”

Section: Chemistry the Nucleic Acid Fractions During Growth And Sporumentioning

confidence: 99%

Chemical and Morphological Studies of Bacterial Spore Formation

Young

Fitz-James

1959

Self Cite

105

The development of both the spore and parasporal protein crystal of Bacillus cereus var. alesti was followed using chemical and cytological techniques. The changes which led to the formation of the fore-spore were similar to those already described for Bacillus cereus. However, adjacent to the developing fore-spore a small inclusion became discernible in phase contrast. This protein inclusion during its growth was differentiated from the chromatln and lipid-containing inclusions by sequential staining techniques.During spore and crystal formation no net synthesis of either nucleic acid was detected. Tracer studies with radioactive phosphorus confirmed that the spore chromatin was derived from that in the vegetative cell. These same studies also indicated that a turnover of ribonucleic acid occurred during the sporulation process.During their formation both the spore and crystal incorporated methionine-asS from the medium and from cellular material into a bound form. Sequential extractions with alkali and with alkaline-thioglycollate reagent revealed that the solubility characteristics of the mature crystal were possibly related to the presence of intermolecular disulphide bonds which developed after the major synthesis of the crystal was complete.The synthetic nature of sporogenesis and crystal formation is discussed with reference to the concept of "endotrophic" sporulation.