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Moran AL, McLachlan RH, Thurber AR. Sea star wasting syndrome reaches the high Antarctic: Two recent outbreaks in McMurdo Sound. PLoS One 2023; 18:e0282550. [PMID: 37498849 PMCID: PMC10374074 DOI: 10.1371/journal.pone.0282550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 07/03/2023] [Indexed: 07/29/2023] Open
Abstract
Sea star wasting syndrome (SSWS) can cause widespread mortality in starfish populations as well as long-lasting changes to benthic community structure and dynamics. SSWS symptoms have been documented in numerous species and locations around the world, but to date there is only one record of SSWS from the Antarctic and this outbreak was associated with volcanically-driven high temperature anomalies. Here we report outbreaks of SSWS-like symptoms that affected ~30% of individuals of Odontaster validus at two different sites in McMurdo Sound, Antarctica in 2019 and 2022. Unlike many SSWS events in other parts of the world, these outbreaks were not associated with anomalously warm temperatures. Instead, we suggest they may have been triggered by high nutrient input events on a local scale. Although the exact cause of these outbreaks is not known, these findings are of great concern because of the keystone role of O. validus and the slow recovery rate of Antarctic benthic ecosystems to environmental stressors.
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Affiliation(s)
- Amy L Moran
- School of Life Sciences, University of Hawai'i at Mānoa, Mānoa, Hawaii, United States of America
| | - Rowan H McLachlan
- Department of Microbiology, College of Science, Oregon State University, Corvallis, Oregon, United States of America
| | - Andrew R Thurber
- Department of Microbiology, College of Science, Oregon State University, Corvallis, Oregon, United States of America
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, United States of America
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2
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Oulhen N, Byrne M, Duffin P, Gomez-Chiarri M, Hewson I, Hodin J, Konar B, Lipp EK, Miner BG, Newton AL, Schiebelhut LM, Smolowitz R, Wahltinez SJ, Wessel GM, Work TM, Zaki HA, Wares JP. A Review of Asteroid Biology in the Context of Sea Star Wasting: Possible Causes and Consequences. THE BIOLOGICAL BULLETIN 2022; 243:50-75. [PMID: 36108034 PMCID: PMC10642522 DOI: 10.1086/719928] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
AbstractSea star wasting-marked in a variety of sea star species as varying degrees of skin lesions followed by disintegration-recently caused one of the largest marine die-offs ever recorded on the west coast of North America, killing billions of sea stars. Despite the important ramifications this mortality had for coastal benthic ecosystems, such as increased abundance of prey, little is known about the causes of the disease or the mechanisms of its progression. Although there have been studies indicating a range of causal mechanisms, including viruses and environmental effects, the broad spatial and depth range of affected populations leaves many questions remaining about either infectious or non-infectious mechanisms. Wasting appears to start with degradation of mutable connective tissue in the body wall, leading to disintegration of the epidermis. Here, we briefly review basic sea star biology in the context of sea star wasting and present our current knowledge and hypotheses related to the symptoms, the microbiome, the viruses, and the associated environmental stressors. We also highlight throughout the article knowledge gaps and the data needed to better understand sea star wasting mechanistically, its causes, and potential management.
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Affiliation(s)
- Nathalie Oulhen
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, Rhode Island
| | - Maria Byrne
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Paige Duffin
- Department of Genetics, University of Georgia, Athens, Georgia
| | - Marta Gomez-Chiarri
- Department of Fisheries, Animal, and Veterinary Science, University of Rhode Island, Kingston, Rhode Island
| | - Ian Hewson
- Department of Microbiology, Cornell University, Ithaca, New York
| | - Jason Hodin
- Friday Harbor Labs, University of Washington, Friday Harbor, Washington
| | - Brenda Konar
- College of Fisheries and Ocean Sciences, University of Alaska, Fairbanks, Alaska
| | - Erin K. Lipp
- Department of Environmental Health Science, University of Georgia, Athens, Georgia
| | - Benjamin G. Miner
- Department of Biology, Western Washington University, Bellingham, Washington
| | | | - Lauren M. Schiebelhut
- Department of Life and Environmental Sciences, University of California, Merced, California
| | - Roxanna Smolowitz
- Department of Biology and Marine Biology, Roger Williams University, Bristol, Rhode Island
| | - Sarah J. Wahltinez
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | - Gary M. Wessel
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, Rhode Island
| | - Thierry M. Work
- US Geological Survey, National Wildlife Health Center, Honolulu Field Station, Honolulu, Hawaii
| | - Hossam A. Zaki
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, Rhode Island
| | - John P. Wares
- Department of Genetics, University of Georgia, Athens, Georgia
- Odum School of Ecology, University of Georgia, Athens, Georgia
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Hart MW, Guerra VI, Allen JD, Byrne M. Cloning and Selfing Affect Population Genetic Variation in Simulations of Outcrossing, Sexual Sea Stars. THE BIOLOGICAL BULLETIN 2021; 241:286-302. [PMID: 35015625 DOI: 10.1086/717293] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
AbstractMany sea stars are well known for facultative or obligate asexual reproduction in both the adult and larval life-cycle stages. Some species and lineages are also capable of facultative or obligate hermaphroditic reproduction with self-fertilization. However, models of population genetic variation and empirical analyses of genetic data typically assume only sexual reproduction and outcrossing. A recent reanalysis of previously published empirical data (microsatellite genotypes) from two studies of one of the most well-known sea star species (the crown-of-thorns sea star; Acanthaster sp.) concluded that cloning and self-fertilization in that species are rare and contribute little to patterns of population genetic variation. Here we reconsider that conclusion by simulating the contribution of cloning and selfing to genetic variation in a series of models of sea star demography. Simulated variation in two simple models (analogous to previous analyses of empirical data) was consistent with high rates of cloning or selfing or both. More realistic scenarios that characterize population flux in sea stars of ecological significance, including outbreaks of crown-of-thorns sea stars that devastate coral reefs, invasions by Asterias amurensis, and epizootics of sea star wasting disease that kill Pisaster ochraceus, also showed significant but smaller effects of cloning and selfing on variation within subpopulations and differentiation between subpopulations. Future models or analyses of genetic variation in similar study systems might benefit from simulation modeling to characterize possible contributions of cloning or selfing to genetic variation in population samples or to understand the limits on inferring the effects of cloning or selfing in nature.
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Occurrence of Ulcerative Lesions in Sea Stars (Asteroidea) of the Northern Gulf of California, USA. J Wildl Dis 2021; 58:215-221. [PMID: 34700341 DOI: 10.7589/jwd-d-21-00044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 06/25/2021] [Indexed: 11/20/2022]
Abstract
To assess the variation of sea star (Asteroidea) populations in the Northern Gulf of California and look for evidence of sea star ulcerative lesions, counts of sea star species were recorded in 2019 using a standard belt-transect technique of 30 m2. During surveys, scuba divers also measured sea stars' diameter and examined them for ulcerative lesions. Ulcerative lesions were noted on Phataria unifascialis only. To verify changes in abundance and size of the two most abundant species, P. unifascialis and Pharia pyramidata, historical data from 2009, 2010, and 2016 were used as comparison and using the same methodology. To evaluate differences in abundance or diameter in sea star species over time, analysis of variance tests (ANOVA) were used. We found a significant reduction in diameter for the species P. unifascialis and P. pyramidata over time (<0.0001), but only P. unifascialis also showed a significant decrease in abundance (P=0.018). The decrease in diameter recorded for these two species, along with the signs of ulcerative lesions found on one of them in 2019, suggest that a potential mortality event occurred and, as a result, new younger (i.e., smaller) recruits could be recovering the population. These results highlight the importance of population monitoring to understand complex reef community dynamics.
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Moritsch MM. Expansion of intertidal mussel beds following disease-driven reduction of a keystone predator. MARINE ENVIRONMENTAL RESEARCH 2021; 169:105363. [PMID: 34030089 DOI: 10.1016/j.marenvres.2021.105363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 05/08/2021] [Accepted: 05/10/2021] [Indexed: 06/12/2023]
Abstract
Disease shapes community composition by removing species with strong interactions. To test whether the absence of keystone predation due to disease produced changes to the species composition of rocky intertidal communities, we leverage a natural experiment involving mass mortality of the keystone predator Pisaster ochraceus from Sea Star Wasting Syndrome. Over four years, we measured dimensions of mussel beds, sizes of Mytilus californianus, mussel recruitment, and species composition on vertical rock walls at six rocky intertidal sites on the central California coast. We also assessed the relationship between changes in mussel cover and changes in sea star density across 33 sites along the North American Pacific coast using data from long-term monitoring. After four years, the lower boundary of the central California mussel beds shifted downward toward the water 18.7 ± 15.8 cm (SD) on the rock and 11.7 ± 11.0 cm in elevation, while the upper boundary remained unchanged. In central California, downward expansion and total area of the mussel bed were positively correlated with mussel recruitment but were not correlated with pre-disease sea star density or biomass. At a multi-region scale, changes in mussel percent cover were positively correlated with pre-disease sea star densities but not change in densities. Species composition of primary substrate holders and epibionts below the mussel bed remained similar across years. Extirpation of the community below the bed did not occur. Instead, this community became limited to a smaller spatial extent while the mussel bed expanded.
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Affiliation(s)
- Monica M Moritsch
- U.S. Geological Survey, Western Geographic Science Center, 350 N. Akron Road, Moffett Field, CA, 94035, USA; University of California, Santa Cruz, Department of Ecology and Evolutionary Biology, 115 McAllister Way, Santa Cruz, CA, 95060, USA.
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Kay SWC, Gehman ALM, Harley CDG. Reciprocal abundance shifts of the intertidal sea stars, Evasterias troschelii and Pisaster ochraceus, following sea star wasting disease. Proc Biol Sci 2020; 286:20182766. [PMID: 31014216 DOI: 10.1098/rspb.2018.2766] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
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.
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Affiliation(s)
- Sharon W C Kay
- 1 Department of Zoology, University of British Columbia , Vancouver, British Columbia , Canada
| | - Alyssa-Lois M Gehman
- 1 Department of Zoology, University of British Columbia , Vancouver, British Columbia , Canada.,3 Hakai Institute , End of Kwakshua Channel, Calvert Island, British Columbia , Canada
| | - Christopher D G Harley
- 1 Department of Zoology, University of British Columbia , Vancouver, British Columbia , Canada.,2 Institute for the Oceans and Fisheries, University of British Columbia , Vancouver, British Columbia , Canada
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Jaffe N, Eberl R, Bucholz J, Cohen CS. Sea star wasting disease demography and etiology in the brooding sea star Leptasterias spp. PLoS One 2019; 14:e0225248. [PMID: 31751376 PMCID: PMC6872156 DOI: 10.1371/journal.pone.0225248] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Accepted: 10/31/2019] [Indexed: 12/26/2022] Open
Abstract
Sea star wasting disease (SSWD) describes a suite of disease signs believed to have led to catastrophic die-offs in many asteroid species, beginning in 2013. While most studies have focused on large, easily visible sea stars with widely-dispersing larvae, less information is available on the effect of this disease outbreak on smaller sea star species, such as the six-armed sea star Leptasterias spp. Unlike many larger sea stars, Leptasterias brood non-feeding young instead of broadcast-spawning planktonic larvae. Limited dispersal and thus limited gene flow may make these sea stars more vulnerable to local selective pressures, such as disease outbreaks. Here, we examined Leptasterias populations at sites along the California coast and documented abundance changes coincident with recent Pacific coast SSWD in 2014. Detection of Leptasterias in central California declined, and Leptasterias were not detected at multiple sites clustered around the San Francisco Bay outflow in the most recent surveys. Additionally, we categorized disease signs in Leptasterias in the field and laboratory, which mirrored those seen in larger sea stars in both settings. Finally, we found that magnesium chloride (MgCl2) slowed the progression of physical deterioration related to SSWD when applied to sea stars in the laboratory, suggesting that MgCl2 may prolong the survival of diseased individuals.
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Affiliation(s)
- Noah Jaffe
- Estuary and Ocean Science Center, Biology Department, San Francisco State University, San Francisco, California, United States of America
| | - Renate Eberl
- Estuary and Ocean Science Center, Biology Department, San Francisco State University, San Francisco, California, United States of America
- Santa Rosa Junior College, Santa Rosa, California, United States of America
| | - Jamie Bucholz
- Estuary and Ocean Science Center, Biology Department, San Francisco State University, San Francisco, California, United States of America
- University of Wisconsin-River Falls, River Falls, Wisconsin, United States of America
| | - C. Sarah Cohen
- Estuary and Ocean Science Center, Biology Department, San Francisco State University, San Francisco, California, United States of America
- * E-mail:
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Gehman AM, Satterfield DA, Keogh CL, McKay AF, Budischak SA. To improve ecological understanding, collect infection data. Ecosphere 2019. [DOI: 10.1002/ecs2.2770] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Alyssa‐Lois M. Gehman
- Odum School of Ecology University of Georgia Athens Georgia USA
- Hakai Institute End of Kwakshua Channel, Calvert Island British Columbia Canada
- Department of Zoology University of British Columbia Vancouver British Columbia Canada
| | - Dara A. Satterfield
- Odum School of Ecology University of Georgia Athens Georgia USA
- Smithsonian Migratory Bird Center Smithsonian Conservation Biology Institute Washington D.C. USA
| | - Carolyn L. Keogh
- Odum School of Ecology University of Georgia Athens Georgia USA
- Department of Environmental Sciences Emory University Atlanta Georgia USA
| | | | - Sarah A. Budischak
- Odum School of Ecology University of Georgia Athens Georgia USA
- W. M. Keck Science Department of Claremont McKenna College Claremont California USA
- W. M. Keck Science Department of Pitzer College Claremont California USA
- W. M. Keck Science Department of Scripps College Claremont California USA
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Harvell CD, Montecino-Latorre D, Caldwell JM, Burt JM, Bosley K, Keller A, Heron SF, Salomon AK, Lee L, Pontier O, Pattengill-Semmens C, Gaydos JK. Disease epidemic and a marine heat wave are associated with the continental-scale collapse of a pivotal predator ( Pycnopodia helianthoides). SCIENCE ADVANCES 2019; 5:eaau7042. [PMID: 30729157 PMCID: PMC6353623 DOI: 10.1126/sciadv.aau7042] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Accepted: 12/17/2018] [Indexed: 05/19/2023]
Abstract
Multihost infectious disease outbreaks have endangered wildlife, causing extinction of frogs and endemic birds, and widespread declines of bats, corals, and abalone. Since 2013, a sea star wasting disease has affected >20 sea star species from Mexico to Alaska. The common, predatory sunflower star (Pycnopodia helianthoides), shown to be highly susceptible to sea star wasting disease, has been extirpated across most of its range. Diver surveys conducted in shallow nearshore waters (n = 10,956; 2006-2017) from California to Alaska and deep offshore (55 to 1280 m) trawl surveys from California to Washington (n = 8968; 2004-2016) reveal 80 to 100% declines across a ~3000-km range. Furthermore, timing of peak declines in nearshore waters coincided with anomalously warm sea surface temperatures. The rapid, widespread decline of this pivotal subtidal predator threatens its persistence and may have large ecosystem-level consequences.
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Affiliation(s)
- C. D. Harvell
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
- Corresponding author.
| | - D. Montecino-Latorre
- One Health Institute, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
| | - J. M. Caldwell
- Department of Biology, Stanford University, Stanford, CA 94040, USA
| | - J. M. Burt
- School of Resource and Environmental Management, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
- Hakai Institute, Heriot Bay, BC V0P 1H0, Canada
| | - K. Bosley
- Fishery Resource Analysis and Monitoring Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration (NOAA), 2032 SE OSU Drive, Newport, OR 97365, USA
| | - A. Keller
- Fishery Resource Analysis and Monitoring Division, Northwest Fisheries Science Center, National Marine Fisheries Service, NOAA, 2725 Montlake Boulevard East, Seattle, WA 98112, USA
| | - S. F. Heron
- NOAA Coral Reef Watch, College Park, MD 20740, USA
- ReefSense Pty Ltd., Townsville, Queensland, Australia
- Marine Geophysical Laboratory, Physics, College of Science and Technology, James Cook University, Townsville, Queensland, Australia
| | - A. K. Salomon
- School of Resource and Environmental Management, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
- Hakai Institute, Heriot Bay, BC V0P 1H0, Canada
| | - L. Lee
- School of Resource and Environmental Management, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
- Hakai Institute, Heriot Bay, BC V0P 1H0, Canada
| | - O. Pontier
- Hakai Institute, Heriot Bay, BC V0P 1H0, Canada
| | | | - J. K. Gaydos
- The SeaDoc Society, Karen C. Drayer Wildlife Health Center–Orcas Island Office, University of California, Davis, 942 Deer Harbor Road, Eastsound, WA 98245, USA
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Microbiome shifts with onset and progression of Sea Star Wasting Disease revealed through time course sampling. Sci Rep 2018; 8:16476. [PMID: 30405146 PMCID: PMC6220307 DOI: 10.1038/s41598-018-34697-w] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 10/24/2018] [Indexed: 12/19/2022] Open
Abstract
The recent outbreak of Sea Star Wasting Disease (SSWD) is one of the largest marine epizootics in history, but the host-associated microbial community changes specific to disease progression have not been characterized. Here, we sampled the microbiomes of ochre sea stars, Pisaster ochraceus, through time as animals stayed healthy or became sick and died with SSWD. We found community-wide differences in the microbiomes of sick and healthy sea stars, changes in microbial community composition through disease progression, and a decrease in species richness of the microbiome in late stages of SSWD. Known beneficial taxa (Pseudoalteromonas spp.) decreased in abundance at symptom onset and through disease progression, while known pathogenic (Tenacibaculum spp.) and putatively opportunistic bacteria (Polaribacter spp. and Phaeobacter spp.) increased in abundance in early and late disease stages. Functional profiling revealed microbes more abundant in healthy animals performed functions that inhibit growth of other microbes, including pathogen detection, biosynthesis of secondary metabolites, and degradation of xenobiotics. Changes in microbial composition with disease onset and progression suggest that a microbial imbalance of the host could lead to SSWD or be a consequence of infection by another pathogen. This work highlights the importance of the microbiome in SSWD and also suggests that a healthy microbiome may help confer resistance to SSWD.
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