(1) Mature sporangia comprised about 30% of the total, were usually unilamellar, 100-400 microns in diameter, and contained a mixture of immature and mature endospores.
(2) The most recently discovered species, Enterocytozoon bieneusi, is known only from the small intestinal enterocytes of patients with the acquired immunodeficiency syndrome, and is easily differentiated from other microsporidia by the precocious development of spore organelles in the sporont and by the poor development of the endospore layer of the spore wall.
(3) Electron microscopic examination of these mutants revealed that these mutations blocked endospore formation at an early stage before septation and caused extensive cell lysis.
(4) More importantly, we tested and verified the hypothesis that there is a relationship between concentrations of dormant, viable endospores of T. vulgaris in lake sediments and the extent of agriculture in the catchments of the lakes.
(5) They were, therefore, shown to be aleuriospores (microcondia), and not endospores.
(6) Male ICR mice were challenged intracerebrally with endospores of Coccidioides immitis and then treated with water (control), fluconazole, amphotericin B (Fungizone), or ketoconazole (Nizoral).
(7) These, in contrast to exospores of the majority of the actinomycetes, are endospores according to their structure and the following criteria: thermostability, the presence of dipicolinic acid, the structure of ultrathin cross-sections studied by electron microscopy, the resistance to novobiocin.
(8) During the process of endospore formation in Bacillus subtilis the appearance of the mother-cell transcription factor sigma K by conversion from its inactive precursor pro-sigma K is coupled to events under the control of the forespore transcription factor sigma G. This intercompartmental coupling is believed to be mediated by the products of a sporulation locus called spoI V F because certain bypass-of-forespore (bof) mutations that map at the spoI V F locus relieve the dependence of pro-sigma K processing on the action of sigma G in the forespore.
(9) The spherule-endospore cycle was maintained in tissue culture medium for 84 days without the formation of detectable hyphae.
(10) Gene expression during endospore formation by Bacillus subtilis is controlled in part by a sporulation-induced form of RNA polymerase, E sigma 29.
(11) The sequential appearance of sigma subunits, which change the promoter recognition specificity of RNA polymerase, may have a key role in controlling the temporal pattern of gene expression required for endospore development in B. subtilis.
(12) Chemical analyses showed that the amount of protein present in vegetative cells of the rifampicin-treated cultures was twice as great as in the untreated cultures but the total protein content of endospores was the same in both cases.
(13) This chitinase, isolated from 48-h culture filtrate of the spherule-endospore-phase C. immitis by affinity adsorption to chitin, formed a line of identity with the IDCF reference antigen and participated in the complement fixation reaction with human serum.
(14) Terminally located, heat-resistant endospores were formed on plates of an enriched agar medium supplemented with L-rhamnose.
(15) The relative abundance of endospores and vegetative cells as well as the protein distributions of these subpopulations may be readily determined from flow microfluorometry data.
(16) A new species, Bacillus naganoensis, is proposed for an obligately aerobic, moderately acidophilic, endospore-forming bacterium that produces a thermostable, aciduric pullulanase (EC 3.2.1.41).
(17) Deletion of sigE, the structural gene for the sporulation-induced RNA polymerase sigma factor, sigma E, prevented endospore formation by Bacillus subtilis.
(18) Because these obligate bacterial parasites of nematodes have not been cultured axenically, the taxonomic relationships described here for each species are based mainly on developmental morphology, fine structure of the respective sporangia and endospores, and their pathogenicity on nematode species.
(19) The results suggest that the crystal and endospore contain one or more common proteins.
(20) Cells were formed, which resembled bacterial endospores by their formation and structure; however, typical refractive spores with envelopes and cortex have not been detected.
Zygospore
Definition:
(n.) Same as Zygosperm.
(n.) A spore formed by the union of several zoospores; -- called also zygozoospore.
Example Sentences:
(1) Zygospore development in Blakeslea trispora was studied using light microscopy, scanning electron microscopy, transmission electron microscopy and freeze fracturing technique.
(2) However, normal mating efficiencies and high zygospore viability are observed in clonal culture, indicating the unbiased production of functional opposite mating-types.
(3) The zygospore contained a very high concentration of chitin (about 17%), three times more than the mycelial concentrations.
(4) Some of these non-recombinant individuals may be derived from "parthenospores" (dormant asexual cells resembling zygospores).
(5) In order to study the mechanism responsible for the uniparental transmission of the mitochondrial genome in crosses between Chlamydomonas reinhardtii and C. smithii, we have analyzed the fate of mitochondrial DNA during gametogenesis, zygospore differentiation and sporulation by hybridization experiments.
(6) In strain 137F of Chlamydomonas reinhardi, the zygospores undergo one round of nuclear DNA replication followed by three divisions to produce octospores.
(7) The young diploid zygote differentiates into dormant zygospore competent to complete meiosis, or more rarely (2-10% of cases) it undergoes mitosis to produce a stable diploid progeny.
(8) Using appropriate restriction enzymes, we have been unable to detect methylation of the mitochondrial DNA during gametogenesis or zygospore formation.
(9) Light is required for total elimination of mt+ mitochondrial DNA in the zygospores.
(10) Changes in the relative abundance of cell constituents of Entomophthora virulenta Hall & Dunn were studied during the various differentiation phases leading to the formation of zygospores.
(11) Zygophores interlock upon contact and then undergo six successive morphological changes to become a zygospore.
(12) Some zygospores do form in crosses of carA mutants and wild types.
(13) Zygospores from this strain undergo two rounds of nuclear DNA replication prior to the formation of octospores.
(14) The results obtained with D. discoideum macrocysts differ from those obtained with other cellular slime moulds--Dictyostelium mucoroides, Dictyostelium giganteum and Polysphondylium pallidum--and are reminiscent of the results reported for germinated zygospores of Phycomyces blakesleeanus.
(15) Descriptions and illustrations of both the zygosporic and sporangial states are presented.
(16) Almost all of the heat-tolerant isolates were pathogenic to suckling mice and had smooth or undulate, or smooth plus undulate zygospore walls.
(17) Although zygospore (mature zygote) formation in P. blakeslleeanus occurs in liquid glucoseglutamate medium, morphological observations are made more easily when cultures are grown on 1-mm-thick agar medium.