scholarly journals Quantitative assessment of actin transcript number in eggs, embryos, and tube feet of the sea star Pisaster ochraceus.

1985 ◽  
Vol 5 (11) ◽  
pp. 3001-3008 ◽  
Author(s):  
I Kovesdi ◽  
M J Smith
Keyword(s):  
Relative Abundance ◽  
Untranslated Region ◽  
Quantitative Assessment ◽  
Developmental Stages ◽  
Sea Star ◽  
Dot Blot ◽  
Pisaster Ochraceus ◽  
Hybridization Kinetic ◽  
Muscle Gene ◽  
Tube Feet

Actin coding sequence cDNA probes were used to quantitate the number of transcripts in RNA from eggs, embryos, and tube feet of the sea star Pisaster ochraceus. Transcript concentrations were measured in both total RNA and in poly(A)+ RNA by titration and hybridization kinetic methods. Surprisingly, the actin transcript number in sea star eggs is two orders of magnitude greater than in sea urchin eggs. There are at least 2.9 X 10(5) actin transcripts per sea star egg, 1.2 X 10(5) per 48-h gastrula and 1.9 X 10(5) per 72-h gastrula. The number of actin transcripts per unit mass of extracted tube foot RNA is lower than in developmental stages. The relative abundance and size of actin transcripts was determined by Northern and dot blot analyses using probes containing actin coding DNA or 3'-untranslated-region sequences. The actin transcript in eggs and embryos is 2,300 nucleotides (nt) long and originates from the Cy (cytoplasmic) gene class. In tube feet, the most abundant actin transcript is 2,200 nt long and originates from the M (muscle) gene class. Tube feet also contain, at lower abundance, 2,300-nt transcripts of the Cy gene type expressed in eggs and embryos.

Quantitative assessment of actin transcript number in eggs, embryos, and tube feet of the sea star Pisaster ochraceus

1985 ◽  
Vol 5 (11) ◽  
pp. 3001-3008
Author(s):  
I Kovesdi ◽  
M J Smith
Keyword(s):  
Relative Abundance ◽  
Untranslated Region ◽  
Quantitative Assessment ◽  
Developmental Stages ◽  
Sea Star ◽  
Dot Blot ◽  
Pisaster Ochraceus ◽  
Hybridization Kinetic ◽  
Muscle Gene ◽  
Tube Feet

Actin coding sequence cDNA probes were used to quantitate the number of transcripts in RNA from eggs, embryos, and tube feet of the sea star Pisaster ochraceus. Transcript concentrations were measured in both total RNA and in poly(A)+ RNA by titration and hybridization kinetic methods. Surprisingly, the actin transcript number in sea star eggs is two orders of magnitude greater than in sea urchin eggs. There are at least 2.9 X 10(5) actin transcripts per sea star egg, 1.2 X 10(5) per 48-h gastrula and 1.9 X 10(5) per 72-h gastrula. The number of actin transcripts per unit mass of extracted tube foot RNA is lower than in developmental stages. The relative abundance and size of actin transcripts was determined by Northern and dot blot analyses using probes containing actin coding DNA or 3'-untranslated-region sequences. The actin transcript in eggs and embryos is 2,300 nucleotides (nt) long and originates from the Cy (cytoplasmic) gene class. In tube feet, the most abundant actin transcript is 2,200 nt long and originates from the M (muscle) gene class. Tube feet also contain, at lower abundance, 2,300-nt transcripts of the Cy gene type expressed in eggs and embryos.

Testing ecological release as a compensating mechanism for mass mortality in a keystone predator

2020 ◽  
Vol 637 ◽  
pp. 59-69 ◽  
Author(s):  
J Sullivan-Stack ◽  
BA Menge
Keyword(s):  
Community Dynamics ◽  
Limiting Factor ◽  
Sea Star ◽  
Top Predator ◽  
Oregon Coast ◽  
Ecological Release ◽  
Keystone Predator ◽  
Pisaster Ochraceus ◽  
Wasting Syndrome

Top predator decline has been ubiquitous across systems over the past decades and centuries, and predicting changes in resultant community dynamics is a major challenge for ecologists and managers. Ecological release predicts that loss of a limiting factor, such as a dominant competitor or predator, can release a species from control, thus allowing increases in its size, density, and/or distribution. The 2014 sea star wasting syndrome (SSWS) outbreak decimated populations of the keystone predator Pisaster ochraceus along the Oregon coast, USA. This event provided an opportunity to test the predictions of ecological release across a broad spatial scale and determine the role of competitive dynamics in top predator recovery. We hypothesized that after P. ochraceus loss, populations of the subordinate sea star Leptasterias sp. would grow larger, more abundant, and move downshore. We based these predictions on prior research in Washington State showing that Leptasterias sp. competed with P. ochraceus for food. Further, we predicted that ecological release of Leptasterias sp. could provide a bottleneck to P. ochraceus recovery. Using field surveys, we found no clear change in density or distribution in Leptasterias sp. populations post-SSWS, and decreases in body size. In a field experiment, we found no evidence of competition between similar-sized Leptasterias sp. and P. ochraceus. Thus, the mechanisms underlying our predictions were not in effect along the Oregon coast, which we attribute to differences in habitat overlap and food availability between the 2 regions. Our results suggest that response to the loss of a dominant competitor can be unpredictable even when based in theory and previous research.

Actin genes from the sea star Pisaster ochraceus

1984 ◽  
Vol 782 (1) ◽  
pp. 76-86 ◽  
Author(s):  
Imre Kovesdi ◽  
Frank Preugschat ◽  
Margaret Stuerzl ◽  
Michael J. Smith
Keyword(s):  
Sea Star ◽  
Pisaster Ochraceus ◽  
Actin Genes

scholarly journals Virome Variation during Sea Star Wasting Disease Progression in Pisaster ochraceus (Asteroidea, Echinodermata)

Viruses ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1332
Author(s):  
Ian Hewson ◽  
Citlalli A. Aquino ◽  
Christopher M. DeRito
Keyword(s):  
Viral Genome ◽  
Marine Invertebrates ◽  
Scar Tissue ◽  
Sea Star ◽  
Wasting Disease ◽  
Viral Genomes ◽  
Normal Tissues ◽  
Pisaster Ochraceus ◽  
Affected Tissue ◽  
External Stimuli

Sea star wasting disease (SSWD) is a condition that has affected asteroids for over 120 years, yet mechanistic understanding of this wasting etiology remains elusive. We investigated temporal virome variation in two Pisaster ochraceus specimens that wasted in the absence of external stimuli and two specimens that did not experience SSWD for the duration of our study, and compared viromes of wasting lesion margin tissues to both artificial scar margins and grossly normal tissues over time. Global assembly of all SSWD-affected tissue libraries resulted in 24 viral genome fragments represented in >1 library. Genome fragments mostly matched densoviruses and picornaviruses with fewer matching nodaviruses, and a sobemovirus. Picornavirus-like and densovirus-like genome fragments were most similar to viral genomes recovered in metagenomic study of other marine invertebrates. Read recruitment revealed only two picornavirus-like genome fragments that recruited from only SSWD-affected specimens, but neither was unique to wasting lesions. Wasting lesion margin reads recruited to a greater number of viral genotypes (i.e., richness) than did either scar tissue and grossly normal tissue reads. Taken together, these data suggest that no single viral genome fragment was associated with SSWD. Rather, wasting lesion margins may generally support viral proliferation.

scholarly journals Mouse testes contain two size classes of actin mRNA that are differentially expressed during spermatogenesis.

1985 ◽  
Vol 5 (7) ◽  
pp. 1649-1654 ◽  
Author(s):  
S H Waters ◽  
R J Distel ◽  
N B Hecht
Keyword(s):  
Untranslated Region ◽  
Cell Types ◽  
Dot Blot ◽  
Size Classes ◽  
Cytoplasmic Actin ◽  
Beta Actin ◽  
Actin Mrna ◽  
Residual Bodies ◽  
Pachytene Spermatocytes ◽  
Sexually Mature

Using several actin isotype-specific cDNA probes, we found actin mRNA of two size classes, 2.1 and 1.5 kilobases (kb), in extracts of polyadenylated and nonpolyadenylated RNA from sexually mature CD-1 mouse testes. Although the 2.1-kb sequence was present in both meiotic and postmeiotic testicular cell types, it decreased manyfold in late haploid cells. The 1.5-kb actin sequence was not detectable in meiotic pachytene spermatocytes (or in liver or kidney cells), but was present in round and elongating spermatids and residual bodies. To differentiate between the beta- and gamma-actin mRNAs, we isolated a cDNA, pMGA, containing the 3' untranslated region of a mouse cytoplasmic actin that has homology to the 3' untranslated region of a human gamma-actin cDNA but not to the 3' untranslated regions of human alpha-, beta-, or cardiac actins. Dot blot hybridizations with pMGA detected high levels of presumptive gamma-actin mRNA in pachytene spermatocytes and round spermatids, with lower amounts found in elongating spermatids. Hybridization with the 3' untranslated region of a rat beta-actin probe revealed that round spermatids contained higher levels of beta-actin mRNA than did pachytene spermatocytes or residual bodies. Both probes hybridized to the 2.1-kb actin mRNA but failed to hybridize to the 1.5-kb mRNA.

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