Growth and differentiation of the water mold Blastocladiella emersonii: cytodifferentiation and the role of ribonucleic acid and protein synthesis.

Lovett, James S.

doi:10.1128/mmbr.39.4.345-404.1975

Cited by 107 publications

(51 citation statements)

References 163 publications

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“…It is hard to tell, however, just how many different polypeptides are being made. At any rate, this synthesis occurs at a time when ribosomes are undergoing a "packaging" for later use during zoospore germination (13). It is tempting to postulate that a phenomenon similar to what we report here may be occurring.…”

Section: Discussionsupporting

confidence: 52%

Nonidentity of ribosomal structural proteins in growing and starved Tetrahymena.

Hallberg¹,

Sutton²

1977

The Journal of Cell Biology

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We have examined the ribosomal structural proteins isolated from vegetatively growing Tetrahymena pyriformis and from cells that had been starved of all nutrients for 24 h. Reproducible, nonartifactual differences in protein complement, primarily associated with the large ribosomal subunit, were found. The kinetics of change in ribosomal protein complement were followed both in refed and in newly starved cells. Furthermore, attempts at correlating a certain protein "phenotype" with a particular functional state of the ribosome were made. It was concluded that the alterations seen could not be correlated with a specific stage in the normal ribosome cycle. We did show, however, that the change in protein complement could occur as a result of altering preexisting ribosomes. In addition, we showed that the change correlates with a decrease in growth rate rather than being caused by the starvation conditions themselves. Speculations as to the functional significance of the protein changes are presented. KEY WORDS ribosomal proteins . nutritional deprivation TetrahyrnenaWe have recently shown (9) that in Tetrahymena pyriformis the ribosome contents of growing cells and nongrowing (starved) cells are regulated at distinct and reproducible levels. Furthermore, the transition from one state (starvation) to the other (exponential growth) involves regulation of ribosome metabolism in a way which indicates that the control of ribosome accumulation in these cells is significantly different than that seen in bacteria. Specifically, we showed that the rate of ribosome synthesis remains constant at a time when the rate of protein synthesis increases some 10-to 15-fold. Also, it appears as if, during this time, ribosomal protein and ribosomal RNA are noncoordinately synthesized. In continuing our studies of ribosome metabolism in T. pyriformis, we have examined further the changes in ribosome number and fraction of active ribosomes in cells shifted either from starvation conditions to growth conditions or vice versa. An unexpected finding of this research is that the proteins of isolated ribosomal subunits from starved and growing cells show reproducible quantitative and qualitative differences when compared by polyacrylamide gel electrophoresis.There have been a number of reports that changes in ribosome structure and/or function can occur in bacteria (e.g., 7, 8, 12) and in eukaryotes (e.g., 6, 10, 15) either during the ribosome cycle or as a response to changes in physiological conditions. We sought to document more carefully the differences we observed, thus hoping we might be able to correlate structural changes with functional ones. We first determined that the differences seen were not the result of an isolation artifact. We than examined the kinetics of change in ribosomal protein "phenotype" when cells were shifted from growth to starvation conditions and

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Section: Discussionsupporting

confidence: 52%

Nonidentity of ribosomal structural proteins in growing and starved Tetrahymena.

Hallberg¹,

Sutton²

1977

The Journal of Cell Biology

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“…B. emersonii zoospores are £agellate and mobile cells that germinate in appropriate environmental conditions in about 40 min at 27 þ 1³C, and grow coenocytically in a nutrient medium [10]. Changing the growth medium to a bu¡ered 10 33 M solution of CaCl 2 induces sporulation in vegetative cells at any moment of growth.…”

Section: B Emersonii's Life Cyclementioning

confidence: 99%

“…Changing the growth medium to a bu¡ered 10 33 M solution of CaCl 2 induces sporulation in vegetative cells at any moment of growth. Under starvation, the cells present an orderly and synchronized sequence of physiological and morphological transitions that culminates in the formation and release of zoospores in about 210^240 min at 27 þ 1³C [6,10]. The half-times (T 50 in minutes) to emergence of the phenotypes are: septate zoosporangia (63 þ 3); papillated zoosporangia (104 þ 2), clivated zoosporangia (164 þ 3) and empty zoosporangia (178 þ 3) [11].…”

Section: B Emersonii's Life Cyclementioning

confidence: 99%

The induction of sporulation in the aquatic fungus Blastocladiella emersonii is dependent on extracellular calcium

Coutinho¹

1999

FEMS Microbiology Letters

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Induction of sporulation in Blastocladiella emersonii is absolutely dependent on extracellular calcium. Vegetative cells grown in media with or without calcium do not sporulate in media devoid of calcium or in CaCl 2 with EGTA. Calcium channel blockers, CoCl 2 and nifedipine, and ionophore A23187 inhibited the induction of sporulation. The calmodulin antagonists trifluoperazine and chlorpromazine inhibited the sporulation when present in the cultures at least 60 min after induction. So, calcium that is accumulated during growth is not sufficient or is not mobilized to initiate sporulation, and a calcium influx is likely to occur by type II calcium channel functions, essential for the response to nutritional starvation. A calmodulin-like protein has been suggested to mediate calcium events in sporulation. ß

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“…The vegetative cell can be induced to sporulate at any time by replacing the growth medium with media lacking nutrients, a process which culminates with the production of new zoospores. Both germination and sporulation are characterized by drastic morphological and biochemical changes, which involve both transcriptional and post-trancriptional controls [18].…”

Section: Introductionmentioning

confidence: 99%

Blastocladiella emersonii expresses a centrin similar to Chlamydomonas reinhardtii isoform not found in late‐diverging fungi

Ribichich

Gomes

2005

FEBS Letters

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Centrins are members of the calcium-binding EFhand protein superfamily which can be divided into two subfamilies, probably associated with different functions: one related to Chlamydomonas reinhardtii centrin, CrCenp, and the other, represented by Saccharomyces cerevisiae isoform, ScCdc31p. ESTs encoding the two isoforms (BeCen1 and BeCen3) from the chytridiomycete Blastocladiella emersonii were isolated, and expression of the CrCenp-type centrin, BeCen1, was analyzed throughout the fungus life cycle. Becen1 mRNA levels increase transiently during sporulation and protein levels present a similar pattern. Immunolocalization studies seem to localize BeCen1 at the basal body zone and in the cytoplasm surrounding the nuclear cap, a zoospore organelle.

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Growth and differentiation of the water mold Blastocladiella emersonii: cytodifferentiation and the role of ribonucleic acid and protein synthesis.

Cited by 107 publications

References 163 publications

Nonidentity of ribosomal structural proteins in growing and starved Tetrahymena.

Nonidentity of ribosomal structural proteins in growing and starved Tetrahymena.

The induction of sporulation in the aquatic fungus Blastocladiella emersonii is dependent on extracellular calcium

Blastocladiella emersonii expresses a centrin similar to Chlamydomonas reinhardtii isoform not found in late‐diverging fungi

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