(n.) One of the spores contained in the asci of lichens and fungi. [See Illust. of Ascus.]
Example Sentences:
(1) To isolate single spores from adhesive ascospores and the mycelium, the suspension was sucked through a combination of sintered-glass plates with different pore sizes.
(2) (2) Coincident disomy increased as a function of the mean number of disomic chromosomes per spore in each dyad, but this increase differed functionally from that expected if coincident disomy in the two ascospores were a simple, meiotically independent, concomitant of multiple disomy.
(3) Fungi of the class Pyrenomycetes (Ascomycotina) form a morphological series ranging from those that shoot ascospores (sexual spores) forcibly from the ascus (spore sac) to fungi that ooze ascospores or have no obvious mechanism for ascospore release.
(4) SPR6 is inessential for sporulation; mutants that lack SPR6 activity sporulate normally and produce viable ascospores.
(5) Complementation tests defined two new genetic loci (spo19 and spo20) essential for ascospore formation, in addition to the 18 known spo loci (Bresch et al.
(6) The results obtained demonstrate that the REC46 gene product modulates mitotic chromosomal stability and recombination and is essential for sporulation (meiosis and ascospore formation).
(7) The mutual attraction of conidia to protoperithecia of the opposite mating type was studied genetically in crosses where a mixture of conidia from two different strains, one of which was marked by an ascospore color mutant gene tan spore (ts), was applied to protoperithecia.
(8) Trehalose is located in the cytoplasm, whereas trehalase resides within the protein and carbohydrate matrix of the innermost major cell wall layer of the ascospore.
(9) Strains of Yarrowia lipolytica forming exclusively spherical ascospores were developed through inbreeding.
(10) The production of diploid ascospores in these strains is apparently under polygenic control.
(11) Electrophoretic measurements on Saccharomyces cerevisiae ascospores indicated the presence of a surface protein layer which can be removed by papain, chymotrypsin or 8 m urea.
(12) Electrophoretic analysis of fruiting body extracts from Neurospora reveals a characteristic protein, apparently absent in vegetative structures and ascospores, and which increases markedly in relative concentration after fertilization.
(13) Due to the characteristic shape of the ascus and ascospores, T. burgeffiana is to be considered a synonym of M. pulcherrima.
(14) The segregation pattern of this character obtained by random spore analysis of the ascospores derived from the cross of the two strains strongly suggests that the resistance to tetracycline is under mitochondrial control.
(15) Potassium sorbate, sodium benzoate, sulfur dioxide, and diethylpyrocarbonate (DEPC) were tested for their effectiveness in preventing the outgrowth of Byssochlamys nivea Westling ascospores.
(16) In this case germination of the binucleate ascospore is not preceded by a mitosis.
(17) Transcripts for four of the genes were detected in all three spore types; mRNA for the fifth gene was detected in macroconidia and microconidia but not in ascospores.
(18) Further implications of this study suggest the importance of extensive ascospore analysis when investigating the perfect states of fungi in order to avoid creating unwarranted new species.
(19) The species forming asci from conjugating gametangial cells and having ellipsoidal ascospores are transferred to Dipodascus.
(20) Development of the ascospores of Sporopachydermia lactativora and S. cereana was studied in ultrathin sections.
Ascus
Definition:
(n.) A small membranous bladder or tube in which are inclosed the seedlike reproductive particles or sporules of lichens and certain fungi.
Example Sentences:
(1) Fungi of the class Pyrenomycetes (Ascomycotina) form a morphological series ranging from those that shoot ascospores (sexual spores) forcibly from the ascus (spore sac) to fungi that ooze ascospores or have no obvious mechanism for ascospore release.
(2) Our results suggest that once the cells are fully derepressed no mitochondrial genetic information has to be expressed during meiosis and ascus formation.
(3) Although growth of two yeast strains characterized by consistent production of two diploid spores per ascus was inhibited in complex presporulation media containing amitrole, a fraction of the cells produced were able to form asci with more than two spores after transfer to acetate sporulation medium.
(4) Due to the characteristic shape of the ascus and ascospores, T. burgeffiana is to be considered a synonym of M. pulcherrima.
(5) Although the rna mutants do not regulate ribosome synthesis during sporulation, all of these diploid strains fail to complete sporulation at 34 degrees C. The cells are arrested after the second meiotic nuclear division but before ascus formation.
(6) strains develop normally to the stage of ascus formation.
(7) The selected hybrids, which carried the greater part of the parental genetic markers and produced asci containing 2,3 and 4 spores per ascus, were placed on sporulation medium.
(8) 2 x n X2 tests showed that frequencies of individual ascus classes from different perithecia were generally homogeneous, as were second division segregation frequencies.
(9) The proportion of spindle overlap and recombinational asci within the group did not change as shown by ascus dissection.
(10) It was demonstrated that the production of less than four spores per ascus in this yeast is not the result of a lack of meiotic products but of the nonutilization of nuclei from meiosis.
(11) The forespores then elongate, close off, and become separated from the ascus cytoplasm by membranes.
(12) The mechanical force responsible apparently originates from the formation of an ectoplasmic mucilage capable of exerting pressure over all of the ascus contents; when the apex of the peduncle ruptures, the ascospores are violently released.
(13) When partially repressed cells were treated with EthBr, no ascus formation was observed after transfer to sporulation medium.
(14) In fungi that produce an ascus containing four spores, a gene conversion event is manifested as 3:1 or 1:3 (or more rarely 4:0 or 0:4) segregations, in contrast to the normal mendelian 2:2 segregation.
(15) The increase in spore numbers per ascus is attributed either to the induction by amitrole in growth medium of cells with more than one nucleus or to the restoration of normal meioses in the multispored asci.
(16) On the basis of mode of ascus formation and ascospore morphology it is included in the genus Metschnikowia Kamienski as a new species, M. lunata.
(17) Ascus formation occurs after isogamous copulation between sexual protuberances which develop at the ends of arthrospores or between two cells, adjacent mycelial cells, or arthrospores.
(18) Ascus formation in Debaryomyces hansenii includes fusion of two cells, usually mother and daughter while still attached to each other, through short protuberances developed from the cross wall between them.
(19) Metschnikowia australis can be differentiated from other Metschnikowia species and varieties by its inability to form chlamydospores, the formation of two needle-shaped ascospores per ascus, lack of glucose fermentation, and lack of assimilation of both methyl-alpha-D-glucoside and glucono-delta-lactone.
(20) Amitrole treatment causes multispored ascus production by cells of a yeast strain whose asci normally contain two diploid spores.