摘要:

ABSTRACT.Mirror‐image symmetry doublets of the ciliateStylonychia pustulatawere obtained from the progenies of dividing cells in which cell division was inhibited by heat‐shocks. In two components consisting of the doublet, the left (cell's) component possessed ciliary organelles arranged in almost the same pattern as in normal singlets, while the right one had surface organelles located in a mirror‐image symmetry of those of the left component. In cell division of the doublet, two sets of ciliary primordia that were arranged in a mirror‐image symmetry developed synchronously in both components. In about 80% of oral primordia (OP) of the right components, the arrangement of the membranellar bands became abnormal. In some cases, OP of the right component were occasionally separated into two longitudinal halves, each consisting of normal membranelles and inverted membranelles. A set of primordia of the paroral membranelles and fronto‐ventro‐transverse cirri was rarely derived from the basal bodies of the right half with a band of normal membranelles. As a result, a third component with the ciliary organelles normally arranged emerged on the right side of the original right component. The differentiation of membranelles and segmentation of the primordial streaks into cim proceeded from anterior to posterior. A cytoplasmic bulge with multiple right marginal cirral rows was frequently formed at the right margin of the doublet. The behavior in the separation of third and fourth streaks from a primordial streak of dorsal cirri was not mirror‐image symmetrical in e

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1991.tb06029.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

ABSTRACT.The symbiont‐containingBlastocrithidia culicisfromAedes vexans, unlike most lower trypanosomatids cultivated in defined media, require only three amino acids: methionine, histidine, and arginine; only three vitamins: thiamin, nicotinamide, and riboflavin; and neither heme nor purine. The bacterium‐like endosymbiont presumably provides the trypanosomatid's other essential nutrie

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1991.tb06030.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

ABSTRACT.Macrostomal cell formation is blocked by the antibiotic cerulenin at levels of 15 μg/ml or higher. Inhibition can be reversed up to 4 h following cerulenin addition by washing and resuspending cells in new, noncerulenin‐treated transforming principle. In these latter cases, additional time equal to the time spent in the inhibitor, is needed for cells to reach control values of transformation. Neither the addition of saturated or unsaturated fatty acids, cholesterol added alone or in combination with stearic acid, nor a mixture of lipids extracted fromTetrahymena voraxreversed the cerulenin effect. Radioisotope incorporation data showed while protein synthesis was reduced by the end of 1 h and tetrahymanol synthesis by the end of 2 h, little or no effect of this inhibitor occurred on RNA or fatty acid synthesis during these times. One interpretation of these results is that cerulenin, by preventing first protein synthesis and later tetrahymanol synthesis, interferes with synthesis and formation of membranes required for the microstome to macrostome transiti

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1991.tb06031.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

ABSTRACT.Analysis of total DNA isolated from the Chrysophyte algaOchromonas danicarevealed, in addition to nuclear DNA, two genomes present as numerous copies per cell. The larger genome (˜120 kilobase pairs or kbp) is the plastid DNA, which is identified by its hybridization to plasmids containing sequences for the photosynthesis genes rbcL, psbA, and psbC. The smaller genome (40 kbp) is the mitochondrial genome as identified by its hybridization with plasmids containing gene sequences of plant cytochrome oxidase subunits I and II. Both the 120‐ and 40‐kbp genomes contain genes for the small and large subunits of rDNA. The mitochondrial genome is linear with terminal inverted repeats of about 1.6 kbp. Two other morphologically similar species were examined,Ochromonas minutaandPoteriochromonas malhamensis.All three species have linear mitochondrial DNA of 40 kbp. Comparisons of endonuclease restriction‐fragment patterns of the mitochondrial and chloroplast DNAs as well as those of their nuclear rDNA repeats failed to reveal any fragment shared by any two of the species. Likewise, no common fragment size was detected by hybridization with plasmids containing heterologous DNA or with total mitochondrial DNA ofO. danica;these observations support the taxonomic assignment of these three organisms to different species. TheOchromonasmitochondrial genomes are the first identified in the chlorophylla/cgroup of algae. Combining these results with electron microscopic observations of putative mitochondrial genomes reported for other chromophytes and published molecular studies of other algal groups suggests that all classes of eukaryote algae may have mitochondrial genomes<100 kbp in size, more like other protistans than land

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1991.tb06032.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

ABSTRACT.During macronuclear development in hypotrichous ciliated protozoans, several thousand macronuclear DNA molecules are amplified several‐hundred fold. We investigated the regulation of this amplification by determining the copy numbers of three different macronuclear DNA molecules in the hypotrichous ciliateEuplotes crassus.Two of the macronuclear DNA molecules were present in approximately 1,000 copies per cell, while the third was present in approximately 6,500 copies per cell. These reiteration levels were achieved either during macronuclear development, or shortly thereafter, and were maintained during vegetative growth. The most abundant macronuclear DNA molecule is present as a single‐copy sequence in the micronuclear genome. Thus, its high copy number results from differential amplification. These results indicate that DNA amplification during macronuclear development is regulated individually for each macronuclear DNA molec

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1991.tb06033.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

ABSTRACT.Studies were completed on the natural population density ofParamecium bursariasyngen 1 and on the life cycle stages to which the individuals belonged. Green paramecia were collected from two streams once every 20 days for over one year: 413 individuals on 26 collection dates in Mikumarikyo stream and 83 individuals on 23 collection dates in Momijidani‐gawa stream. Individuals in nature did not maintain at a steady density but fluctuated greatly depending on the month. It seems that conjugation occurred from April to June in the Mikumarikyo stream and from May to June in the Momijidani‐gawa stream. The appearance of individuals with mating ability might be related closely to increasing population so that sexual reproduction probably occurred near the peak of the population density. The 413 individuals from Mikumarikyo stream were examined to determine their position within the life cycle; 309 (74%) were immature, 55 (13%) were adolescent, and 49 (12%) were mature. No senile individuals were observed. The fraction of individuals with mating ability was generally less than 30% at any collection. Four mating types were observed occurring with about equal frequencies in mature individuals. The results show the frequencies of the recessive genes for mating types (aandb) are higher than for dominant genes (AandB). Of 83 individuals from Momijidani‐gawa stream, 44 (52%) were immature, 21 (25%) were adolescent, and 18 (21%) were mature. Again, no senile individuals were observed. Because only two mating types were found, II and III (genotypesaaB‐andaabb), it seems possible that the dominant geneAwas rare or absent in the Momijidani‐gawa p

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1991.tb06034.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

ABSTRACT.The settling tomite stage of the apostomeHyalophysa chattonisecretes a phoretic cyst wall composed of chitin, mucopolysaccharides, and protein. Within 1 1/2 h after settling, an electron‐dense proteinaceous cyst layer (the outer layer) is formed from secretions originating at the base of the kineties and from the thick pellicular layer between the kineties. The inner cyst layer, composed primarily of chitin (acidic and neutral polysaccharides are also present), is secreted across the entire cell surface. Cyst wall formation is completed within 6 h. The fine structure of endocyst secretion resembles stages in the secretion of chitin by fungi, yeasts, and arthropods. A proteinaceous attachment peduncle is secreted to anchor the cell to a shrimp host and is formed by the release of electron‐dense secretory bodies from the cell's ventral surf

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1991.tb06035.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Brusca, R. C.&Brusca, G. J. 1990. Invertebrates. Sinauer, Sunderland, MassachusettsMiller, H. R. P. (ed.) 1990.Immunity to and Diagnosis of Internal Parasitism. Vol. 9, no. 2.Revue Scientifiqueet Technique, Ofie International Des Epizootics. Office International Des Epizootics, Paris, France.Preston, T. M., King, C. A.&Hyams, J. S. 1990.The Cytoskeleton and Cell Motility. Chapman and Hall, New York, New York.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1991.tb06036.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1991.tb06037.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1991.tb06038.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY