Differences in formation of vegetative cells and their walls in Trebouxia and Pseudotrebouxia as further evidence for the classification of these genera

1985 ◽  
Vol 17 (3) ◽  
pp. 281-287 ◽  
Author(s):  
E. Peveling ◽  
J. König
Keyword(s):  
Vegetative Cell ◽  
Cell Walls ◽  
Vegetative Cells

AbstractThe formation of vegetative cells from zoospores and the morphogenesis of the multilayered cell walls during this process was observed in some Trebouxia and Pseudotrebouxia species. In Trebouxia species, e.g. Trebouxia erici, the wall of the vegetative cell is formed around the zoospore while in Pseudotrebouxia species, e.g. Pseudotrebouxia corticola, firstly an autosporangium with its wall is formed then the autosporangium further divides.

ChemInform Abstract: Synthesis of a Hexasaccharide Repeating Unit from Bacillus anthracis Vegetative Cell Walls.

ChemInform ◽  
2008 ◽  
Vol 39 (26) ◽  
Author(s):  
Matthias A. Oberli ◽  
Pascal Bindschaedler ◽  
Daniel B. Werz ◽  
Peter H. Seeberger
Keyword(s):  
Bacillus Anthracis ◽  
Vegetative Cell ◽  
Cell Walls

Basal Body and Flagellar Development During the Vegetative Cell Cycle and the Sexual Cycle of Chlamydomonas Reinhardii

1974 ◽  
Vol 16 (3) ◽  
pp. 529-556 ◽  
Author(s):  
T. CAVALIER-SMITH
Keyword(s):  
Basal Body ◽  
Vegetative Cell ◽  
Amorphous Material ◽  
Sexual Cycle ◽  
Transitional Region ◽  
Basal Bodies ◽  
Vegetative Cells ◽  
Chlamydomonas Reinhardii ◽  
Body Development ◽  
Microtubular Roots

Basal body development and flagellar regression and growth in the unicellular green alga Chlamydomonas reinhardii were studied by light and electron microscopy during the vegetative cell cycle in synchronous cultures and during the sexual life cycle. Flagella regress by gradual shortening prior to vegetative cell division and also a few hours after cell fusion in the sexual cycle. In vegetative cells basal bodies remain attached to the plasma membrane by their transitional fibres and do not act as centrioles at the spindle poles during division. In zygotes the basal bodies and associated microtubular roots and cross-striated connexions all dissolve, and by 6.5 h after mating all traces of flagellar apparatus and associated structures have disappeared. They remain absent for 6 days throughout zygospore maturation and then are reassembled during zygospore germination, after meiosis has begun. Basal body assembly in developing zygospores occurs close to the plasma membrane (in the absence of pre-existing basal bodies) via an intermediate stage consisting of nine single A-tubules surrounding a central ‘cartwheel’. Assembly is similar in vegetative cells (and occurs prior to cell division), except that new basal bodies are physically attached to old ones by amorphous material. In vegetative cells, amorphous disks, which may possibly be still earlier stages in basal-body development occur in the same location as 9-singlet developing basal bodies. After the 9-singlet structure is formed, B and C fibres are added and the basal body elongates to its mature length. Microtubular roots, striated connexions and flagella are then assembled. Both flagellar regression and growth are gradual and sequential, the transitional region at the base of the flagellum being formed first and broken down last. The presence of amorphous material at the tip of the axoneme of growing and regressing flagella suggests that the axoneme grows or shortens by the sequential assembly or disassembly at its tip. In homogenized cells basal bodies remain firmly attached to each other by their striated connexions. The flagellar transitional region, and parts of the membrane and of the 4 microtubular roots, also remain attached; so also do new developing basal bodies, if present. These structures are well preserved in homogenates and new fine-structural details can be seen. These results are discussed, and lend no support to the idea that basal bodies have genetic continuity. It is suggested that basal body development can be best understood if a distinction is made between the information needed to specify the structure of a basal body and that needed to specify its location and orientation.

Actin During Pollen Germination

1986 ◽  
Vol 86 (1) ◽  
pp. 1-8
Author(s):  
J. HESLOP-HARRISON ◽  
Y. HESLOP-HARRISON ◽  
M. CRESTI ◽  
A. TIEZZI ◽  
F. CIAMPOLINI
Keyword(s):  
Medium Release ◽  
Pollen Tube ◽  
Vegetative Cell ◽  
Pollen Germination ◽  
Pollen Grain ◽  
Actin Microfilaments ◽  
Vegetative Cells ◽  
Stage Of Development ◽  
Angiosperm Species

The cytoplasm of the vegetative cell of the ungerminated pollen grain of Endymton non-scriplus and other angiosperm species contains numerous fusiform bodies sometimes exceeding 15μm in length and 2.5 μm in width, which bind fluorescent-labelled phalloidin and are likely therefore to constitute a storage form of actin. The bodies are dispersed during the activation of the pollen, being replaced by aggregates of slender phalloidin-binding fibrils, which converge towards the germination apertures and are present in the emerging pollen tube. The storage bodies appear to be homologous with crystalline-fibrillar structures, shown in an earlier paper to be abundantly present in the vegetative cells of Nicotiana pollen. These are composed of massive aggregates of linearly disposed units with individual widths of 4–7 nm, probably to be interpreted as actin microfilaments. Vegetative-cell protoplasts from mature but ungerminated pollen disrupted in osmotically balancing medium release extended phalloidin-binding fibrils of a kind not observed in the intact grain. It is suggested that these are derived by the rapid dissociation of the compact actin storage bodies present in the vegetative cell at this stage of development.

scholarly journals DNA demethylation by ROS1a in rice vegetative cells promotes methylation in sperm

2019 ◽  
Vol 116 (19) ◽  
pp. 9652-9657 ◽  
Author(s):  
M. Yvonne Kim ◽  
Akemi Ono ◽  
Stefan Scholten ◽  
Tetsu Kinoshita ◽  
Daniel Zilberman ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Vegetative Cell ◽  
Seed Viability ◽  
Dna Demethylation ◽  
Central Cell ◽  
Dna Glycosylase ◽  
Rice Seed ◽  
Vegetative Cells ◽  
Active Dna Demethylation ◽  
Cell Genome

Epigenetic reprogramming is required for proper regulation of gene expression in eukaryotic organisms. In Arabidopsis, active DNA demethylation is crucial for seed viability, pollen function, and successful reproduction. The DEMETER (DME) DNA glycosylase initiates localized DNA demethylation in vegetative and central cells, so-called companion cells that are adjacent to sperm and egg gametes, respectively. In rice, the central cell genome displays local DNA hypomethylation, suggesting that active DNA demethylation also occurs in rice; however, the enzyme responsible for this process is unknown. One candidate is the rice REPRESSOR OF SILENCING1a (ROS1a) gene, which is related to DME and is essential for rice seed viability and pollen function. Here, we report genome-wide analyses of DNA methylation in wild-type and ros1a mutant sperm and vegetative cells. We find that the rice vegetative cell genome is locally hypomethylated compared with sperm by a process that requires ROS1a activity. We show that many ROS1a target sequences in the vegetative cell are hypomethylated in the rice central cell, suggesting that ROS1a also demethylates the central cell genome. Similar to Arabidopsis, we show that sperm non-CG methylation is indirectly promoted by DNA demethylation in the vegetative cell. These results reveal that DNA glycosylase-mediated DNA demethylation processes are conserved in Arabidopsis and rice, plant species that diverged 150 million years ago. Finally, although global non-CG methylation levels of sperm and egg differ, the maternal and paternal embryo genomes show similar non-CG methylation levels, suggesting that rice gamete genomes undergo dynamic DNA methylation reprogramming after cell fusion.

Presence of endotoxin in vegetative cells of Bacillus thuringiensis var. sotto

1970 ◽  
Vol 16 (9) ◽  
pp. 905-906 ◽  
Author(s):  
P. Luthy ◽  
Y. Hayashi ◽  
T. A. Angus
Keyword(s):  
Bacillus Thuringiensis ◽  
Vegetative Cell ◽  
Vegetative Cells ◽  
Cell Extracts

Endotoxin was found in vegetative cell extracts of Bacillus thuringiensis var. sotto. The distribution of the toxin in fractions obtained by centrifugation at different speeds indicates an association with cell particles, most likely membranes.

A SEROLOGICAL COMPARISON OF VEGETATIVE CELL AND ASCUS WALLS AND THE SPORE COAT OF SACCHAROMYCES CEREVISIAE

1966 ◽  
Vol 12 (3) ◽  
pp. 485-488 ◽  
Author(s):  
I. J. Snider ◽  
J. J. Miller
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Structure ◽  
Vegetative Cell ◽  
Proteolytic Enzyme ◽  
Spore Coat ◽  
Vegetative Cells

Cross-agglutination tests with sera obtained by injection of vegetative cells, asci, and spores into rabbits revealed no immunological distinction between the walls of vegetative cells and asci, whereas the spore coats were found to be serologically distinct from cell and ascus walls. Treatment of vegetative cells and asci with periodate or a proteolytic enzyme before agglutination tests gave results which suggest that the critical antigen is a protein structure.

scholarly journals Cell-specific cis-natural antisense transcripts (cis-NATs) in the sperm and the pollen vegetative cells of Arabidopsis thaliana

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 93
Author(s):  
Peng Qin ◽  
Ann E. Loraine ◽  
Sheila McCormick
Keyword(s):  
Gene Expression ◽  
Vegetative Cell ◽  
Cell Types ◽  
Antisense Transcripts ◽  
Vegetative Cells ◽  
Natural Antisense Transcripts ◽  
Protein Coding ◽  
Regulate Gene Expression ◽  
Genome Wide ◽  
Gene Models

Background: cis-NATs (cis-natural antisense transcripts) are transcribed from opposite strands of adjacent genes and have been shown to regulate gene expression by generating small RNAs from the overlapping region. cis-NATs are important for plant development and resistance to pathogens and stress. Several genome-wide investigations identified a number of cis-NAT pairs, but these investigations predicted cis-NATS using expression data from bulk samples that included lots of cell types. Some cis-NAT pairs identified from those investigations might not be functional, because both transcripts of cis-NAT pairs need to be co-expressed in the same cell. Pollen only contains two cell types, two sperm and one vegetative cell, which makes cell-specific investigation of cis-NATs possible. Methods: We investigated potential protein-coding cis-NATs in pollen and sperm using pollen RNA-seq data and TAIR10 gene models using the Integrated Genome Browser.  We then used sperm microarray data and sRNAs in sperm and pollen to determine possibly functional cis-NATs in the sperm or vegetative cell, respectively. Results: We identified 1471 potential protein-coding cis-NAT pairs, including 131 novel pairs that were not present in TAIR10 gene models. In pollen, 872 possibly functional pairs were identified. 72 and 56 pairs were potentially functional in sperm and vegetative cells, respectively. sRNAs were detected at 794 genes, belonging to 739 pairs. Conclusion: These potential candidates in sperm and the vegetative cell are tools for understanding gene expression mechanisms in pollen.

scholarly journals Detection of Food Poisoning (Bacillus cereus) Pathogen in Cooked and Refrigerated Rice Samples

2019 ◽  
Vol 62 (3) ◽  
pp. 172-177
Author(s):  
Shagufta Ambreen Shaikh ◽  
Anila Sidiqui ◽  
Shagufta Naz ◽  
Seema Ismat
Keyword(s):  
General Population ◽  
Bacillus Cereus ◽  
Vegetative Cell ◽  
Food Poisoning ◽  
Local Market ◽  
Staple Food ◽  
Vegetative Cells ◽  
Cooked Rice ◽  
Rice Samples ◽  
Favorable Conditions

  Rice is a staple food of Pakistan. It is being contaminated with several food poisoning causing bacterial and mold contaminants. In this study 100 different rice samples were collected from local market of Karachi city. The presence of Bacillus cereus vegetative cell and survival of their spores were quantitavely analyzed after cooking and refrigeration. From the study it was observed that out of 100 rice samples, 25% cooked/refrigerated samples were positive for the presence of B.cereus spores , even there were few samples which showed increase of count due to improper (cooking and refrigeration ) which causes the germination and proliferation of spores into vegetative cells under favorable conditions. The detection of increased count of B. cereus even after cooking and refrigeration treatments is very alarming since cooking is supposed to be best treatment given to the raw food. Different rice dishes are being frequently consumed by the general population and are also available on different shops (as biryanis or fried rice), hence, detection of B. cereus in cooked rice samples will be useful to control any outbreak of food poisoning cases especially in summer seasons.    

scholarly journals On a Malay Form of Chlorococcum humicola (Näg.), Rabenh

1919 ◽  
Vol 44 (299) ◽  
pp. 473-482 ◽  
Author(s):  
B. Muriel Bristol
Keyword(s):  
Cell Wall ◽  
Mother Cell ◽  
Cell Walls ◽  
Starch Granules ◽  
Red Pigment ◽  
Vegetative Cells ◽  
Daughter Cells ◽  
Set Up ◽  
Mother Cell Wall ◽  
Adult Cells

Summary The material described has been obtained from cultures of a sample of dried soil, which was sent from the Malay States about two years before the cultures were set up. The vegetative cells are spherical or subspherical, solitary or collected together into mucilaginous strata, very variable in size, being from 20–80 μ in diameter, each with a thin cellulose cell-wall and a single parietal chloroplast containing from one to several pyrenoids and numerous starch granules. In adult cells a quantity of yellow oil is stored, in which a bright red pigment is often dissolved. The cytoplasm is reticulate. The young cells contain a single minute nucleus and one pyrenoid, both of which multiply by repeated division so that the adult cells are cœnocytic with many pyrenoids. Propagation takes place, by successive bipartition of the contents of the mother-cell, into 8–16 or numerous biciliate zoogonidia which may develop asexually or may act as facultative gametes. In both cases direct development into vegetative cells takes place. Aplanospore-formation may also take place, preceded by the multiplication by constriction of the nuclei of the mother-cell. The aplanospores remain imbedded in a mucous stratum, and enter into a palmelloid state in which further bipartitions may take place. Eventually, the palmelloid cells either acquire cilia and behave as normal zoogonidia or they develop directly into vegetative cells. True vegetative division does not take place, but the cell-contents may divide into two daughter-cells which immediately acquire new cell-walls and are set free as vegetative cells by the dissolution of the mother-cell-wall. Chloroaoccum humicola, differing in no essential particulars from that in the Malay soil, has been found to occur almost universally in English soils. The limit of its resistance against desiccation and of its retention of vitality has been shown, by investigations on long-dried English soils, to lie somewhere between seventy and eighty years. In conclusion, I wish to express my thanks to Professor G. S. West for his valuable help throughout this work.

THE PHOSPHORUS FRACTIONS OF BACILLUS CEREUS AND BACILLUS MEGATERIUM: I. A COMPARISON OF SPORES AND VEGETATIVE CELLS

1955 ◽  
Vol 1 (7) ◽  
pp. 502-519 ◽  
Author(s):  
P. C. Fitz-James
Keyword(s):  
Nucleic Acid ◽  
Total Phosphorus ◽  
Cell Walls ◽  
Dry Weight ◽  
Phosphorus Fractions ◽  
Weight Basis ◽  
Insoluble Residue ◽  
Vegetative Cells ◽  
Acid Labile ◽  
Total P

The phosphorus fractions of the spores and young vegetative cells of B. cereus and B. megaterium were compared using the methods of Schneider and of Schmidt and Thannhauser. Differences were found, not only between the two types of cell, but also between the species studied. The spores of B. cereus and B. megaterium contained, on a dry weight basis, similar amounts of nucleic acid, yet the spores of B. megaterium contained twice as much total phosphorus as those of B. cereus. The excess phosphorus of B. megaterium spores was present as an acid and alkali insoluble residue and was made up of empty spore coats. While this same fraction accounted for only 4% of the total phosphorus of B. cereus spores it made up some 60% of that of B. megaterium. A similar fraction from vegetative cells was low in phosphorus. The spore coats of B. megaterium, in contrast to the cell walls were lysozyme-resistant. Cold acid-soluble and lipid phosphorus could be properly estimated only on disrupted spores. Disruption also proved essential for the ready extraction of spore nucleic acids with hot TCA, but did not greatly alter the solubility of the residue phosphorus. Ribosenucleic acid (RNA) comprised 50% of the total phosphorus in the spores of B. cereus (3–4% of the dry weight) but only 25% in B. megaterium spores. In both species the RNA of the vegetative forms accounted for a larger proportion of the total P of the cell. Ribonuclease digested the RNA of spores and vegetative cells to the same degree. The Schmidt and Thannhauser method was found more suitable than the Schneider method for the estimation of desoxyribosenucleic acid (DNA). The DNA content of B. cereus spores was about 1% of their dry weight; that of B. megaterium spores was slightly less. Some 12–20% of the phosphorus of B. cereus spores and 6% of that of the young vegetative cells was present as acid-labile (non-nucleic acid) phosphorus which exhibited some of the characteristics of polymetaphosphate.

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