(1) The first, or parasitic classifications of Sabouraud, rests on the morphology of the dermatophytes on the hair in vivo (Achorion, Trichophyton endothrix or ectothrix microides and megaspores, Microsporum) or on the absence of growth on the hair in vivo (Epidermophyton).
(2) The more mature megaspore of Isoetes contains proplastids up to 4 mum in greatest dimension.
(3) The disposition of these organelles in the cell is such that each of the four megaspores delimited during cytokinesis contains a single proplastid.
(4) In Isoetes all 4 megaspores of every tetrad survive and develop, while in Marsilea the mature megasporangium contains a single functional megaspore.
(5) beta-Lectin activity is absent from the megaspore wall.
(6) The resemblance of the plastids in the more mature megaspore to the bodies produced by evagination earlier in development suggests a common identity.
(7) It is possible, however, in the megaspore at least, that the distribution of the activity may to some extent be influenced by a system of exine channels which communicates between the two domains of the wall during sporogenesis.
(8) It is suggested that an explanation to account for the 2 different mechanisms might be sought in regard to the degree of developmental success enjoyed by the individual megaspores in the 2 plants.
(9) The earlier changes observed are in the megaspore which contained many reserve substances (starch; nucleic acids; ascorbic acid; proteins) and enzymes (peroxidase, succinate dehydrogenase, acid phosphatase, alkaline phosphatase and ATP-ase).
(10) The spermatozoid approaches the egg through layers of mucilage that surround the megaspores.
Microspore
Definition:
(n.) One of the exceedingly minute spores found in certain flowerless plants, as Selaginella and Isoetes, which bear two kinds of spores, one very much smaller than the other. Cf. Macrospore.
Example Sentences:
(1) Finally, the potential of using microinjection for transforming embryogenic microspores has been evaluated.
(2) A study has been made of the systematic fluctuations in the frequency of microspores in these compartments, when plants are grown under rigidly controlled conditions.
(3) Normal stamens exhibited the synthesis of many polypeptides not found in the mutant, from microspore mother cell to the preanthesis stages.
(4) The microspores were purified by centrifugation and washing and cultured in liquid medium on a membrane support.
(5) Rice (Oryza sativa L., 2n=24) anthers containing microspores in the early-uninucleate to first-mitosis stages were induced successfully to develop into plants in vitro through an intermediary step of callus formation.
(6) With both constructs, the appearance of GUS activity in developing anthers was correlated with the onset of microspore mitosis and increased progressively until anthesis (pollen shed).
(7) It is evident that not only do microspores mature at different rates, but that the maturation rate of individual microspores varies during the developmental sequence.
(8) Hoechst 33342, a nuclear stain, alone or in combination with either or both of the other stains, could be used to highlight the nuclear developmental stage of the microspores.
(9) This family is composed of 10 to 15 closely related genes which are expressed in early stages of microspore development.
(10) Blepharoplast formation and function has been investigated by light and electron microscopy in developing microspores of the water fern Marsilea vestita.
(11) Embryogenic microspores continued to increase in size throughout the culture period and fluoresced when stained with fluoresecein diacetate (FDA).
(12) During normal meiosis the distribution of microtubules follows a specific temporal and spatial pattern that reflects the polar nature of microspore formation.
(13) High expression of the transcript is limited to microspores entering and undergoing mitosis.
(14) Farmer's lung, caused by the inhalation of microspores--particularly of the genus, Thermoactinomyces--has been recognised for the past 30-40 years as a condition affecting adult farm workers, especially up to the mid-sixties when undried crops were still threshed indoors.
(15) Above all, the microspore-derived embryo system is recommended to both plant breeders and plant biochemists for the selection and multiplication of plants of superior quality.
(16) A new allele of the maize A1 gene, a gene required for anthocyanin pigment biosynthesis, was identified in a genetic stock exhibiting a high frequency of chromosome breakage at the second microspore mitosis.
(17) The microspores of Marsilea and Pilularia have non-specific esterase activity concentrated in the intine inthe immediate vicinity of the germinal site; that is, above the position of the future male gametangia.
(18) 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).
(19) The ultrastructure of the mature spermatozoid of Marsilea vestita was studied after its release from the microspore and prior to its penetration of the egg.
(20) With the microblending technique a mean of 9.4 green plants and 0.4 albino plants were regenerated per plated anther while a mean of only 2.8 green and 0.17 albino plants per anther were regenerated from microspores isolated after pestle maceration of the anthers.