- Salivary gland of the tick vector of East Coast fever. III. The ultrastructure of sporogony in Theileria parva. [Journal Article]
- TCTissue Cell 1982; 14(1):183-206
- Sporogony of the sporozoan Theileria parva in the salivary gland of the tick vector of East Coast fever was studied in electron micrographs. The findings differ in several respects from previous inte…
Sporogony of the sporozoan Theileria parva in the salivary gland of the tick vector of East Coast fever was studied in electron micrographs. The findings differ in several respects from previous interpretations based upon light microscopy. Cytokinesis of the primary sporoblast to form secondary and tertiary sporoblasts is not substantiated. Instead it is suggested that the parasite develops as a ramifying, multinucleate syncytium rapidly increasing in size and complexity until it gives rise to myriad sporozoites in a terminal episode of cytoplasmic fission. The proliferating nuclei initially occupy peripheral lobules that are continuous with a central labyrinth of branching and anastomosing processes which present a very large surface area for interchange of metabolites with the host cell cytoplasm. The membrane of the labyrinth is rich in cytostomes, but no evidence if found to bulk uptake of host cytoplasmic matrix or organelles into food vacuoles. Rhoptries are the first of the polar organelles of the parasite to develop and are associated with dense plaques irregularly distributed on the inner aspect of the parasite membrane. Micronemes form independently of the rhoptries at a later stage. After 3-4 days of tick feeding, sporogeny is complete and the infected salivary gland cell contains up to 50, 000 spherical or ovoid sporozoites about 1 micrometer in diameter. These are limited by a simple plasma membrane. The inner layer of the 'pellicle', the polar ring, and the conoid described for zoites of other Apicomplexa are lacking. Maturational changes are noted in sporozoites after sporogony is completed. Micronemes appear to increase in size, and possibly in number, from days 3-5 and the majority take up positions immediately subjacent to the plasmalemma.
- Physiology of sporeforming bacteria associated with insects: metabolism of Bacillus popilliae grown in third-instar Popillia japonica Newman larvae. [Journal Article]
- AMAppl Microbiol 1975; 30(1):20-5
- The timing and relative participation of concurrent pathways of carbohydrate metabolism as well as the extent of terminal respiratory activity were determined by radiorespirometry with 14-C substrate…
The timing and relative participation of concurrent pathways of carbohydrate metabolism as well as the extent of terminal respiratory activity were determined by radiorespirometry with 14-C substrates and by enzyme assays for vegetative and sporulating cells of the bacterium Bacillus popilliae cultured in whole, intact Popillia japonica (Japanese beetle) larvae. During vegetative proliferation, the pentose phosphate pathway predominates in the bacterial cells with minor involvement of the Embden-Meyerhof-Parnas pathway. As the cells proceed through sporulation, pentose phosphate and Embden-Meyerhof-Parnas activity remains constant. No tricarboxylic cycle activity is evident during growth and sporulation of B. popilliae. The results demonstrate (i) predominantly aerobic metabolism for carbohydrate assimilation within in vivo sporulating cells, (ii) a major contrast to the metabolism of other aerobic sporeforming bacteria that exhibit derepression of tricarboxylic acid cycle enzymatic activity at the onset of sporulation, and (iii) no causal necessity of the cycle to B. popilliae sporogeny.
- In vitro cultivation of cells and a microsporidian parasite of Biomphalaria glabrata (Pulmonata: Basommatophora). [Journal Article]
- ANAnn N Y Acad Sci 1975; 266:513-27
- Cells from juvenile heart and gonads of B. glabrata have been grown in vitro for more than 1 year. These cell cultures are not actively mitotic but show other characteristics normal for metazoan cell…
Cells from juvenile heart and gonads of B. glabrata have been grown in vitro for more than 1 year. These cell cultures are not actively mitotic but show other characteristics normal for metazoan cells in culture. They are tolerant of widely variable culture conditions. Challenges with mitogens, mutagens, and altered cyclic nucleotide levels have failed to induce mitosis. A microsporidian parasite grows intracellularly in vitro. The ultrastructural details of sporogeny and pansporoblastic maturation are described. Several pansporoblasts can occur in one snail cell; maturation of spores within a pansporoblast is not synchronous, which is a highly unusual feature. Time-lapse cinemicrography reveals engulfment of free spores by snail cells. Polar tube and sporoplasm release are reported photographically. Drug therapy failed to eliminate the protozoan. The potential value of microsporidia in schistosome control programs is evaluated as slight.
- Possible involvement of beta-lactamase in sporulation in Bacillus cereus. [Journal Article]
- JBJ Bacteriol 1970; 102(1):64-71
- Nonreverting beta-lactamase-negative strains were isolated from the beta-lactamase-constitutive strain, Bacillus cereus 569 H. These strains differed from both beta-lactamase-inducible and -constitut…
Nonreverting beta-lactamase-negative strains were isolated from the beta-lactamase-constitutive strain, Bacillus cereus 569 H. These strains differed from both beta-lactamase-inducible and -constitutive strains not only in failure to produce beta-lactamase but also in failure to autolyze on aging, delayed sporulation, and failure to release free spores from sporangia when produced. The addition of B. cereus beta-lactamase of 15% purity to a final concentration of 10 IU/ml stimulates sporulation and particularly the release of free spores in culture from sporangia of strain 569 (inducible wild-type), 569/H (constitutive mutant of 569), and HPen(-), a nonreverting beta-lactamase strain isolated from 569/H in this laboratory. Cultures of HPen(-) did not release free spores without this treatment. Similar stimulation of sporulation and spore release by beta-lactamase from B. cereus were observed in another beta-lactamase-negative strain derived from 569/H as well as in certain sporogeny mutants of B. subtilis. The beta-lactamase preparation used in these experiments was free of peptidases, proteases, and autolysins capable of solubilizing wall from vegetative cells. These results, taken with our previous finding that a soluble peptidoglycan inducer becomes available in cultures of B. cereus only at sporulation and that normal derepression of beta-lactamase accompanies normal sporulation, suggest that beta-lactamase in B. cereus may be involved in peptidoglycan metabolism during sporulation and possibly the breakdown of sporangial wall with the concomitant release of mature spores.