scholarly journals HISTOCHEMICAL CHANGES IN GONADAL NUTRIENT RESERVES CORRELATED WITH NUTRITION IN THE SEA STARS, PISASTER OCHRACEUS AND PATIRIA MINIATA

1976 ◽  
Vol 151 (2) ◽  
pp. 357-369 ◽  
Author(s):  
SISTER M. AQUINAS ◽  
NIMITZ O. P.
Keyword(s):  
Sea Stars ◽  
Pisaster Ochraceus ◽  
Patiria Miniata ◽  
Nutrient Reserves ◽  
Histochemical Changes

scholarly journals Genetic variation associated with lower susceptibility to sea star wasting syndrome in the keystone species, Pisaster ochraceus

2021 ◽  
Author(s):  
Andrea Burton ◽  
Sarah Gravem ◽  
Felipe Barreto
Keyword(s):  
Genetic Variation ◽  
Keystone Species ◽  
Disease Status ◽  
Sea Star ◽  
Sea Stars ◽  
Protein Coding ◽  
Functional Studies ◽  
Pisaster Ochraceus ◽  
Wasting Syndrome ◽  
Asymptomatic Individuals

The keystone species, Pisaster ochraceus, suffered mass mortalities along the northeast Pacific Ocean from Sea Star Wasting Syndrome (SSWS) outbreaks in 2013-2016. Causation of SSWS is still debated, leading to concerns as to whether outbreaks will continue to impact this species. Considering the apparent link between ocean temperature and SSWS, the future of this species and intertidal communities remains uncertain. We surveyed populations of sea stars along the Oregon coast in 2016, two years after the epidemic began. Cohabitation of asymptomatic and symptomatic individuals allowed us to ask whether lower susceptibility in asymptomatic individuals differed genetically. We performed restriction site-associated DNA sequencing (2bRAD-seq) to genotype thousands of single nucleotide polymorphism (SNP) loci. By comparing allele frequencies between symptomatic and asymptomatic individuals, we detected three loci that may be under selection. A multivariate analysis showed a clear separation between groups based on disease status in two of the three geographic regions, along with several regions across the genome having small statistical contributions to this separation. A draft annotation of protein-coding regions allowed us to identify 120 predicted genes that are linked to these markers and are putatively associated with lower susceptibility. Our results suggest that some variation in disease severity can be attributed to genetic variation. However, differences in phenotype have a highly polygenic nature with no single or few genomic regions having strong predictive effects. The genes associated with these regions may form the basis for functional studies aiming to understand disease progression in infected individuals.

Observations on the reproduction and development of Pisaster ochraceus (Brandt)

1981 ◽  
Vol 59 (9) ◽  
pp. 1700-1707 ◽  
Author(s):  
Alex Fraser ◽  
Johanna Gomez ◽  
E. Brian Hartwick ◽  
Michael J. Smith
Keyword(s):  
Normal Development ◽  
Oocyte Size ◽  
Sea Stars ◽  
Pisaster Ochraceus ◽  
Potential Source ◽  
Molecular Studies ◽  
Laboratory Maintenance

Pisaster ochraceus was investigated as a potential source of embryonic material for molecular studies. Minimal conditions for laboratory maintenance of gravid sea stars and a method for induction of spawning are described. Data on oocyte size, yield, and fertilizability are presented as well as a timetable of normal development to bipinnaria larvae and measures of developmental synchrony.

scholarly journals Reciprocal abundance shifts of the intertidal sea stars, Evasterias troschelii and Pisaster ochraceus , following sea star wasting disease

2019 ◽  
Vol 286 (1901) ◽  
pp. 20182766 ◽  
Author(s):  
Sharon W. C. Kay ◽  
Alyssa-Lois M. Gehman ◽  
Christopher D. G. Harley
Keyword(s):  
Indirect Effects ◽  
Interference Competition ◽  
Disease Outbreaks ◽  
Ecological Communities ◽  
Population Declines ◽  
Sea Star ◽  
Sea Stars ◽  
Wasting Disease ◽  
Field Surveys ◽  
Pisaster Ochraceus

Disease emergence occurs within the context of ecological communities, and disease driven declines in host populations can lead to complex direct and indirect ecological effects. Varying effects of a single disease among multiple susceptible hosts could benefit relatively resistant species. Beginning in 2013, an outbreak of sea star wasting disease (SSWD) led to population declines of many sea star species along the west coast of North America. Through field surveys and laboratory experiments, we investigated how and why the relative abundances of two co-occurring sea star species, Evasterias troschelii and Pisaster ochraceus , shifted during the ongoing wasting epidemic in Burrard Inlet, British Columbia, Canada. We hypothesized that Evasterias is competitively inferior to Pisaster but more resistant to SSWD. Thus, we predicted that SSWD-induced declines of Pisaster could mitigate the negative effects of SSWD on Evasterias , as the latter would experience competitive release. We document shifts in sea star abundance from 2008–2017: Pisaster abundance and mean size declined during the outbreak, while Evasterias abundance increased from relatively rare to numerically dominant within the intertidal. When exposed to symptomatic sea stars, Pisaster and Evasterias both showed signs of SSWD, but transmission and susceptibility was lower in Evasterias. Despite diet overlap documented in our field surveys, Evasterias was not outcompeted by Pisaster in laboratory trails conducted with the relatively small Pisaster available after the outbreak. Interference competition with larger Pisaster , or prey exploitation by Pisaster during the summer when Evasterias is primarily subtidal, may explain the rarity of Evasterias prior to Pisaster declines. Our results suggest that indirect effects mediated by competition can mask some of the direct effects of disease outbreaks, and the combination of direct and indirect effects will determine the restructuring of a community after disturbance.

scholarly journals What doesn’t kill them makes them stronger: an association between elongation factor 1-αoverdominance in the sea starPisaster ochraceusand “sea star wasting disease”

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1876 ◽  
Author(s):  
John P. Wares ◽  
Lauren M. Schiebelhut
Keyword(s):  
Pacific Coast ◽  
Functional Relationship ◽  
Elongation Factor ◽  
Sea Star ◽  
Sea Stars ◽  
Wasting Disease ◽  
Pisaster Ochraceus ◽  
The Pacific ◽  
The Relationship ◽  
Elongation Factor 1

In recent years, a massive mortality event has killed millions of sea stars, of many different species, along the Pacific coast of North America. This disease event, known as ‘sea star wasting disease’ (SSWD), is linked to viral infection. In one affected sea star (Pisaster ochraceus), previous work had identified that the elongation factor 1-αlocus (EF1A) harbored an intronic insertion allele that is lethal when homozygous yet appears to be maintained at moderate frequency in populations through increased fitness for heterozygotes. The environmental conditions supporting this increased fitness are unknown, but overdominance is often associated with disease. Here, we evaluate populations ofP. ochraceusto identify the relationship between SSWD and EF1A genotype. Our data suggest that there may be significantly decreased occurrence of SSWD in individuals that are heterozygous at this locus. These results suggest further studies are warranted to understand the functional relationship between diversity at EF1A and survival inP. ochraceus.

H3 histone RNA in eggs and embryos of the sea star Pisaster ochraceus

1988 ◽  
Vol 66 (10) ◽  
pp. 1040-1044
Author(s):  
D. K. Banfield ◽  
J. D. G. Boom ◽  
B. M. Honda ◽  
M. J. Smith
Keyword(s):  
Sea Urchins ◽  
Transcript Abundance ◽  
Single Copy ◽  
Sea Star ◽  
Sea Stars ◽  
Pisaster Ochraceus ◽  
Homologous Sequences ◽  
Order Of Magnitude ◽  
Transcript Concentration ◽  
Rna Concentration

Unlike sea urchins, sea stars have little stored histone RNA in their eggs. In an effort to quantify this difference, we have measured H3 RNA concentration in eggs and embryos of the sea star Pisaster ochraceus. The amount of H3 transcript in P. ochraceus 12-h embryos has been measured by RNA excess hybridization kinetics, using a single-strand 32P-labelled coding sequence probe. There are 1 × 105 H3 transcripts in each 12-h embryo. Putative egg H3 transcript concentration was estimated by reciprocal plots. The number of egg H3 homologous sequences (150/egg) is at least an order of magnitude less than rare complex-class, single-copy nuclear DN A transcripts. Slot blots and Northern blots indicate that sea star embryos do not reach the level of H3 transcript abundance seen in sea urchins until at least 16 h of development.

scholarly journals What doesn’t kill them makes them stronger: An association between elongation factor 1-α overdominance in the sea star Pisaster ochraceus and "sea star wasting disease”

2016 ◽  
Author(s):  
John P. Wares ◽  
Lauren M Schiebelhut
Keyword(s):  
Pacific Coast ◽  
Functional Relationship ◽  
Elongation Factor ◽  
Sea Star ◽  
Sea Stars ◽  
Wasting Disease ◽  
Pisaster Ochraceus ◽  
The Pacific ◽  
The Relationship ◽  
Elongation Factor 1

In recent years, a massive plague has killed millions of sea stars, of many different species, along the Pacific coast of North America. This disease, known as 'sea star wasting disease' (SSWD), is thought to be caused by viral infection. In the affected sea star Pisaster ochraceus, previous work had identified that the elongation factor 1-α (EF1A) locus harbored an intronic insertion allele that is lethal when homozygous yet appears to be maintained at moderate frequency in populations through increased fitness for heterozygotes. The environmental conditions supporting this increased fitness are unknown, but overdominance is often associated with disease. Here, we evaluate populations of P. ochraceus to identify the relationship between SSWD and EF1A genotype. Our data suggest that there may be significantly decreased infection or mortality rates in individuals that are heterozygous at this locus. These results suggest further studies to understand the functional relationship between diversity at EF1A and survival in P. ochraceus.

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