(1) beta-Phenethyl alcohol, fluoroacetic acid, and 2-picolinic acid inhibited anaerobic sporogenesis almost completely, butyrate biosynthesis by >87%, and acetate accumulation by 50 to 62%, showing a direct relationship between butyric type of fermentation and anaerobic sporulation.
(2) Spores of Bacillus megaterium QM B1551 germinated, elongated, and resporulated (microcycle sporogenesis) in simple chemically defined media which permitted no cell division.
(3) Wall ultrastructure and sporogenesis were studied in plasmodia of Henneguya adiposa Minchew which infects the channel catfish, Ictalurus punctatus (Rafinesque).
(4) The resulting transformants appear normal for cytokinesis, and also are fully competent for sporogenesis, confirming that reintroduction of the myosin gene is sufficient to restore these properties.
(5) These data, accounting for 70 to 75% of the initial radioactivity, confirmed the hypothesis that the major role of acetate, and subsequently of poly-beta-hydroxybutyrate, in sporulation of B. cereus T is to provide carbon precursors and energy for sporogenesis.
(6) Microcycle sporogenesis induced in Bacillus cereus T by phosphate limitation occurs over a narrow range of phosphate to spore inoculum ratios.
(7) The study of the antibiotic effect on bacterial sporogenesis showed negative results which are discussed in the paper along two directions: (1) the antibiotics did not probably participate in regulation of the bacteria cell differentiation, (2) the antibiotics regulated the bacterial sporogenesis though their effect was not as yet detected because of methodical difficulties.
(8) Most of the information about the ultrastructural changes accompanying the sporogenesis refer to the first stage of the process, but nothing has been published about the evolution of the sporulation septum during maturation.
(9) Differences in the effect of the same sugars on the formation of spores by these microorganisms and clearly expressed sporogenesis-inhibiting effect of glucose (and also of lactose in clostridia) have been demonstrated.
(10) Sporogenesis is initiated by the envelopment of one vegetative cell by another.
(11) Although under some conditions the sporogenesis and the synthesis of S-variant toxin began two hours earlier than these processes in R-variant cells which were observed, respectively, after 10 or 12 hours from the beginning of the experiment, the intensities of sporogenesis and toxin production as well as the exit of spores and toxin excretion from cells were similar after 24 hours.
(12) According to this hypothesis, either the lysS1 enzyme is altered during sporogenesis or some physiological or structural aspect of this developmental phase can stabilize the mutant phenotype and thereby rescue cells from thermal death.
(13) At periods in spore outgrowth and sporogenesis these cells become refractory to thermal death.
(14) Acetate and a small amount of a tricarboxylic acid cycle intermediate were the minimal organic metabolic requirements for microcycle sporogenesis.
(15) Two anther cDNA libraries were constructed, one from anthers of 1.2-1.8 mm long buds (sporogenesis library) and one from anthers of 1.8-4.0 mm long buds (microspore development library).
(16) Sporogenesis by the biphasic system was more rapid, convenient, and economical, and yielded as many or more heat-resistant (80 C, 10 min) spores per milliliter as by the conventional technique.
(17) Ultrathin sections were prepared from cultures of Bacillus megaterium QM B1551 undergoing microcycle sporogenesis (initial spore to primary cell to second-stage spore without intervening cell division) on a chemically defined medium.
(18) Sporogenesis was asynchronous with simple unicellular stages adjacent to more complex forms with developing polar capsules and valves.
(19) It was suggested that bacitracin and the serine proteases were not specific regulators of sporogenesis in B. licheniformis and their biological function under the natural conditions included, respectively, the antibiotic action and hydrolysis of proteins and peptides of the environment and cells.
(20) The onset of sporogenesis was always accompanied by a new accumulation of glycogen in sporulating hyphae.
Tapetum
Definition:
(n.) An area in the pigmented layer of the choroid coat of the eye in many animals, which has an iridescent or metallic luster and helps to make the eye visible in the dark. Sometimes applied to the whole layer of pigmented epithelium of the choroid.
Example Sentences:
(1) A tapetum or basal retinula cells are not developed.
(2) Ophthalmoscopic examinations performed during recovery revealed changes of slight increase in tapetal islets, suggestive of a slight progression and organization within the tapetum followed by an arrest of the toxic insult within the tapetal tissue.
(3) In conditions that simulate the tapetum they continue normal gametophytic development to produce functional pollen.
(4) It was concluded that the morphology and structural architecture of choroidal melanocytes of dogs or cats are different from those of human eyes and closely correspond to the tapetum.
(5) These observations led to this comparative study on several morphological, histochemical and biochemical parameters on mature ferrets, dogs and cats including: (1) the number of center tapetum cell layers, (2) thickness of center tapetum, (3) presence of a microtubule-like structure in each tapetal rod, (4) presence of electron-dense cores in tapetal rods after prolonged fixation in glutaraldehyde, (5) retention of reflection or color of tapetum after prolonged glutaraldehyde fixation, (6) zygomatic bones of eye orbits, (7) zinc content in tapetum, (8) cysteine in the tapetum, (9) cysteine sulfinic acid decarboxylase in liver, (10) thickness of retina from center tapetum, (11) anterior view of skull configuration, and (12) lateral view of skull configuration (jaw and teeth).
(6) Blebs made with Hanks' solution over the pigmented RPE resorbed 22% faster than those over the tapetum.
(7) The receptory area of the ocellus terminates in a tapetum which contains granules, soluble in alcohol.
(8) The retina and tapetum of kittens born to taurine-deficient and taurine-supplemented mothers were compared.
(9) This species possesses a choroidally located tapetum lucidum in the superior fundus and over this tapetal area, melanosomes are absent from the RPE cells.
(10) A semicircular area of the retinal epithelium in the superior fundus is further specialized as a tapetum lucidum.
(11) In contrast, the tapetum lowers luminance threshold by at most 0.16 log unit.
(12) It is speculated that the hereditary defect may be defective synthesis of the tapetal rodlet matrix or of the zinc-complexing substance of the tapetum.
(13) As the entire fundus is overlain with a choroidally located tapetum cellulosum, only at the extreme periphery is an occasional melanosome present in these epithelial cells.
(14) These rodlets are the reflective material of the tapetum and are arranged with their long axes perpendicular to the incoming light.
(15) The reflecting material of the tapetum lucidum of the sea catfish (Arius felis) was chromatographed on Sephadex LH-20 in methanol-dimethyl sulphoxide-formic acid.
(16) Over the tapetum however it is reduced to a trilaminate structure and when associated with the indented capillary profiles is further reduced to a single thickened basal lamina.
(17) As for a receptor mechanism, the tapetum, or reflective layer of the retina, present in most land mammals, but absent in humans, enhances dim illumination.
(18) This pathophysiological correlation indicates that the occiptiomesencephalic projections of the internal sagittal stratum and the peristriate interhemispheric connections of the tapetum are not necessary for smooth pursuit system function.
(19) Plants expressing the modified glucanase from tapetum-specific promoters exhibited reduced male fertility, ranging from complete to partial male sterility.
(20) Its principal features include (1) the presence of a dense matrix, possibly a new type of tapetum lucidum, in the pigment epithelium, (2) a well developed photoreceptor layer containing large rods, single, double and triple cones, and (3) well developped inner nuclear and plexiform layers, with the exception of horizontal cells which are few and relatively small.