An ultrastructural study of cell division in the coralline red alga Bossiella orbigniana

1993 ◽  
Vol 71 (3) ◽  
pp. 434-446 ◽  
Author(s):  
Sharon Broadwater ◽  
Joe Scott ◽  
Dawn Field ◽  
Bill Saunders ◽  
Jewel Thomas
Keyword(s):  
Cell Division ◽  
Red Algae ◽  
Polar Region ◽  
Algal Cell ◽  
Metaphase Plate ◽  
Red Alga ◽  
Nucleolar Material ◽  
Red Algal ◽  
Polar Gap ◽  
Rough Er

This investigation of Bossiella orbigniana (Decaisne) Silva ssp. orbigniana represents the first ultrastructural account of cell division in the order Corallinales. The mitotic process in this alga is differentiated from that of other red algae by a combination of characters. During prometaphase–metaphase the division poles contain unusual membrane arrangements including quantities of smooth-surfaced membranes and elongate extensions of perinuclear rough ER. At anaphase extensive remnants of nucleolar material attach to the chromosomes, trailing them to the poles. After telophase, the distal nucleus continues to move toward the apex resulting in much greater nuclear segregation than accomplished by anaphase alone. Cytokinesis is temporally displaced from mitosis and displaced distally from the metaphase plate. A reevaluation of ultrastructural patterns of red algal cell division suggests that there are two basic types of mitosis, the polar gap type and the polar fenestrations type to which B. orbigniana belongs. These two types are differentiated by a number of characters with the most important being the configuration of the prometaphase–metaphase polar region and spindle origin. Key words: Bossiella, cell division, Corallinales, mitosis, phylogeny, red algae.

Actin rings in cytokinesis of apical cells in red algae

1996 ◽  
Vol 74 (6) ◽  
pp. 971-974 ◽  
Author(s):  
David J. Garbary ◽  
A. Rosa McDonald
Keyword(s):  
Cell Division ◽  
Red Algae ◽  
Ring Formation ◽  
Transverse Wall ◽  
Actin Ring ◽  
Dense Ring ◽  
Red Algal ◽  
First Time ◽  
Actin Rings ◽  
Peripheral Cytoplasm

Actin rings are demonstrated for the first time in florideophyte red algae in Audouinella botryocarpa (Acrochaetiales) and Tiffaniella snyderae and Griffithsia pacifica (Ceramiales). Rings formed a complete circle in the peripheral cytoplasm prior to the development of the septum by furrowing. In the uninucleate A. botryocarpa, ring formation precedes mitosis. In all species F-actin initially has a diffuse to longitudinal alignment throughout the cell. The actin realigns and then contracts to form a dense actin ring. Following cell division, aggregations of actin are maintained along the transverse wall in at least G. pacifica and A. botryocarpa, and a dense ring of actin was observed around a pit plug in T. snyderae. The occurrence of actin rings in cell division of members of the Acrochaetiales and Ceramiales is consistent with ultrastructural observations on red algal unicells and suggests that actin rings are part of the ancestral cytokinetic mechanism in red algae. Keywords: actin rings, cell division, cytokinesis, cytoskeleton, microfilaments, Rhodophyta.

Ultrastructure of cell division in the unicellular red alga Flintiella sanguinaria

1986 ◽  
Vol 64 (3) ◽  
pp. 516-524 ◽  
Author(s):  
Joe Scott
Keyword(s):  
Cell Division ◽  
Cell Formation ◽  
Taxonomic Revision ◽  
Red Alga ◽  
Cell Periphery ◽  
Animal Cells ◽  
Porphyridium Purpureum ◽  
Structural Details ◽  
Red Algal ◽  
Reduced Forms

Cell division was examined with the electron microscope in the unicellular red alga Flintiella sanguinaria. Flintiella morphologically resembles Porphyridium purpureum, the only other red algal unicell that has been examined for ultra-structural details of cell division. Both genera are in the order Porphyridiales (Bangiophyceae), an unnatural assemblage of reduced forms in great need of taxonomic revision. Before mitosis, the nucleus migrates to the cell periphery. As in all red algae examined, except Porphyridium, the nucleus-associated organelle is a polar ring. At prometaphase, one or two microtubule-containing cytoplasmic invaginations penetrate the nucleus at each pole. By metaphase an intranuclear spindle is found in association with a typical metaphase chromosomal plate. The nuclear envelope is intact except for a single, large gap at each pole. Perinuclear endoplasmic reticulum is absent. An elongated anaphase interzonal midpiece is formed which breaks down at telophase. The daughter nuclei are widely separated by the chloroplast, which is constricted at the same time as daughter cell formation occurs by a cleavage furrow associated with a finely filamentous region similar to the contractile ring found in many animal cells. Because of pronounced differences in several mitotic features, it is concluded that Flintiella is not closely related to Porphyridium and instead shows closer phylogenetic ties with other macroscopic genera.

A contaminant DNA barcode sequence reveals a new red algal order, Corynodactylales (Nemaliophycidae, Florideophyceae)

Botany ◽  
2017 ◽  
Vol 95 (6) ◽  
pp. 561-566 ◽  
Author(s):  
Gary W. Saunders ◽  
Katelyn L. Wadland ◽  
Eric D. Salomaki ◽  
Christopher E. Lane
Keyword(s):  
Phylogenetic Analysis ◽  
Red Algae ◽  
Dna Barcode ◽  
Genomic Data ◽  
Red Alga ◽  
Vegetative Development ◽  
Red Algal ◽  
Multigene Phylogenetic Analysis

Routine DNA barcode surveys of red algae can occasionally yield contaminant sequences owing to the diverse epi/endo flora and fauna that can inhabit these species. Often discarded as nuisance data, further exploration in this study led to the discovery of an unusual red alga with a highly characteristic vegetative development in which the diminutive primary vegetative filaments are terminated by distinctive monosporangia. This entity is described here as Corynodactylus rejiciendus G.W. Saunders gen. et sp. nov. Generating genomic data from the host and associated epiphytic flora, and subsequently subtracting out genes of the former, facilitated a multigene phylogenetic analysis supporting recognition of Corynodactylaceae fam. nov. and Corynodactylales ord. nov. as a distant sister to the order Balliales in the subclass Nemaliophycidae.

scholarly journals Ultrastructure of cell division in the unicellular red alga Porphyridium purpureum

1982 ◽  
Vol 60 (1) ◽  
pp. 85-97 ◽  
Author(s):  
Kathleen L. Schornstein ◽  
Joe Scott
Keyword(s):  
Red Algae ◽  
Structural Diversity ◽  
Red Alga ◽  
Early Prophase ◽  
Gap Formation ◽  
Porphyridium Purpureum ◽  
General Belief ◽  
Polar Gap ◽  
Ultrastructural Characteristics ◽  
Division Axis

Mitosis in the unicellular red alga Porphyridium purpureum was studied with the electron microscope. During early prophase two bipartite nucleus associated organelles (NAOs) are seen in a region that will become one of the division poles. The division axis is established by the migration of one NAO. Microbodies are associated with the poles throughout the mitotic cycle. At prometaphase the nuclear envelope (NE) subjacent to each NAO forms a nuclear pocket which breaks down or opens to form a large gap. Concomitant with polar gap formation the large NAO portion proximal to the NE disperses whereas the smaller distal NAO portion remains throughout subsequent mitotic stages. At metaphase a plate arrangement of chromatin is seen and indistinct kinetochores are associated with a single microtubule. Chromatin moves to the poles followed by pronounced interzonal midpiece (IZM) elongation. After IZM abscission the nuclei migrate to opposite ends of the elongating cell. Cytokinesis occurs by means of an ingrowing cleavage furrow. A comparison of mitotic ultrastructural characteristics in Porphyridium with data available on mitosis in other red algae suggests that structural diversity may be of taxonomic significance; a comparison with other lower eukaryotes suggests that the overall features of mitosis in red algae do not support the general belief that this group is one of the most primitive of all eukaryotes.

scholarly journals Ultrastructure and Differentiation in Chara Sp. II. Mitosis

1967 ◽  
Vol 20 (5) ◽  
pp. 883 ◽  
Author(s):  
JD Pickett-Heaps
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Division ◽  
Asymmetric Cell Division ◽  
Metaphase Plate ◽  
Early Prophase ◽  
Cell Organelles ◽  
Vegetative Cells ◽  
Nucleolar Material ◽  
Dividing Cells ◽  
Late Telophase

The ultrastructure of some dividing cells of Chara are described. No centrioles have ever been detected in vegetative cells. Asymmetric cell division, forming a predetermined pattern of cells, was apparently not preceded by any characteristic grouping of cell organelles. The nucleoli became dispersed during pre-prophase, and most of the nucleolar material appeared intimately associated with the chromosomes throughout division, although some seemed excluded from the nucleus at late telophase. Polar zones of endoplasmic reticulum were formed in early prophase, and attachment of microtubules to daughter chromosomes slightly preceded the formation of a very precisely aligned metaphase plate. The chromosome arms were also apparently all aligned in the plane of this plate.

scholarly journals Studies on the Regulation of Algal Growth by Gibberellin

1971 ◽  
Vol 24 (4) ◽  
pp. 1115 ◽  
Author(s):  
RC Jennings
Keyword(s):  
Red Algae ◽  
Algal Growth ◽  
Red Alga ◽  
General Phenomenon ◽  
Hypnea Musciformis ◽  
Fast Growing ◽  
High Concentrations ◽  
Amo 1618 ◽  
Slow Growing

CCC and Amo.1618, at relatively high concentrations only, inhibited the growth of excised branch apices of the red alga Hypnea musciformis. Neither GA3 nor GA7 stimulated growth of the alga in the presence or absence of these compounds, and gibberellin-like material extracted from H. musciformis also failed to stimulate growth. However, both gibberellins stimulated the growth of slow-growing, but not fast-growing, branch apices of the related red alga Gracilaria verucosa. It is concluded that endogenous gibberellins may not regulate the growth of H. musciformis, but this is likely to be a peculiarity of this species and not a general phenomenon in red algae.

Nucleologenesis in Trypanosoma cruzi

2016 ◽  
Vol 22 (3) ◽  
pp. 621-629 ◽  
Author(s):  
Tomás Nepomuceno-Mejía ◽  
Reyna Lara-Martínez ◽  
Roberto Hernández ◽  
María de Lourdes Segura-Valdez ◽  
Luis F. Jiménez-García
Keyword(s):  
Cell Division ◽  
Trypanosoma Cruzi ◽  
Ethylenediaminetetraacetic Acid ◽  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Light And Electron Microscopy ◽  
Nucleolar Organizer ◽  
Nuclear Bodies ◽  
Nucleolar Organizer Regions ◽  
Nucleolar Material

AbstractNucleolar assembly is a cellular event that requires the synthesis and processing of ribosomal RNA, in addition to the participation of pre-nucleolar bodies (PNBs) at the end of mitosis. In mammals and plants, nucleolar biogenesis has been described in detail, but in unicellular eukaryotes it is a poorly understood process. In this study, we used light and electron microscopy cytochemical techniques to investigate the distribution of nucleolar components in the pathway of nucleolus rebuilding during closed cell division in epimastigotes of Trypanosoma cruzi, the etiologic agent of American trypanosomiasis. Silver impregnation specific for nucleolar organizer regions and an ethylenediaminetetraacetic acid regressive procedure to preferentially stain ribonucleoprotein revealed the conservation and dispersion of nucleolar material throughout the nucleoplasm during cell division. Furthermore, at the end of mitosis, the argyrophilic proteins were concentrated in the nucleolar organizer region. Unexpectedly, accumulation of nucleolar material in the form of PNBs was not visualized. We suggest that formation of the nucleolus in epimastigotes of T. cruzi occurs by a process that does not require the concentration of nucleolar material within intermediate nuclear bodies such as mammalian and plant PNBs.

scholarly journals Growth and Differentiation of the Golgi Apparatus in the Red Alga, Callithamnion Roseum

1974 ◽  
Vol 14 (3) ◽  
pp. 633-655
Author(s):  
EVA KONRAD HAWKINS
Keyword(s):  
Plasma Membrane ◽  
Fine Structure ◽  
Golgi Apparatus ◽  
Red Algae ◽  
Developmental Stages ◽  
Spore Wall ◽  
Red Alga ◽  
Wall Formation ◽  
Golgi Vesicles

The fine structure of the Golgi apparatus during development of tetrasporangia of Calli-thamnion roseum is described. Dictyosomes and associated vesicles of 4 developmental stages of sporangia are examined. The wall of sporangia exhibits a heretofore unseen cuticle in red algae. Development of the spore wall and a new plasma membrane around spores occurs through fusion of adjacent Golgi vesicles along the periphery of cells. Observations are discussed in relation to wall formation and expansion of tetrads and in comparison with other work on growth and differentiation of the Golgi apparatus.

First reports of the red alga Hypoglossum caloglossoides from the Mediterranean and the Red Sea

2015 ◽  
Vol 58 (4) ◽  
Author(s):  
Razy Hoffman ◽  
Michael J. Wynne
Keyword(s):  
Red Sea ◽  
Algal Species ◽  
Red Alga ◽  
Red Algal ◽  
The Mediterranean

AbstractThe occurrence of the red algal species

The cell cycle of symbiotic Chlorella. I. The relationship between host feeding and algal cell growth and division

1985 ◽  
Vol 77 (1) ◽  
pp. 225-239
Author(s):  
P.J. McAuley
Keyword(s):  
Cell Division ◽  
Cell Growth ◽  
Host Cell ◽  
Algal Cell ◽  
Host Cells ◽  
Digestive Cell ◽  
Host Feeding ◽  
Digestive Cells ◽  
Division Factor ◽  
Cell Mitosis

When green hydra were starved, cell division of the symbiotic algae within their digestive cells was inhibited, but algal cell growth, measured as increase in either mean volume or protein content per cell, was not. Therefore, control of algal division by the host digestive cells must be effected by direct inhibition of algal mitosis rather than by controlling algal cell growth. The number of algae per digestive cell increased slightly during starvation, eventually reaching a new stable level. A number of experiments demonstrated that although there was a relationship between host cell and algal mitosis, this was not causal: the apparent entrainment of algal mitosis to that of the host cells could be disrupted. Thus, there was a delay in algal but not host cell mitosis when hydra were fed after prolonged starvation, and algae repopulated starved hydra with lower than normal numbers of algae (reinfected aposymbionts or hydra transferred to light after growth in continuous darkness). Two experiments demonstrated a direct stimulation of algal cell division by host feeding. Relationships of algal and host cell mitosis to numbers of Artemia digested per hydra were different, and in hydra fed extracted Artemia algal, but not host cell, mitosis was reduced in comparison to that in control hydra fed live shrimp. It is proposed that algal division may be dependent on a division factor, derived from host digestion of prey, whose supply is controlled by the host cells. Numbers of algae per cell would be regulated by competition for division factor, except at host cell mitosis, when the algae may have temporarily uncontrolled access to host pools of division factor. The identity of the division factor is not known, but presumably is a metabolite needed by both host cells and algae.

Sign in / Sign up

Export Citation Format

Share Document