Sea Star Wasting Disease in \u3cem\u3eAsterias forbesi\u3c/em\u3e along the Atlantic Coast of North America

As keystone species, sea stars serve to maintain biodiversity and species distribution through trophic level interactions in marine ecosystems. Recently, Sea Star Wasting Disease (SSWD) has caused widespread mass mortality in several sea star species from the Pacific Coast of the United States of America (USA) and Asterias forbesi on the Atlantic Coast. A densovirus, named Sea Star associated Densovirus (SSaDV), has been associated with the wasting disease in Pacific Coast sea stars, and limited samples of A. forbesi. The goal of this research is to examine the pathogenesis of SSWD in A. forbesi on the Atlantic Coast of the USA and to determine if SSaDV is associated with the wasting disease in this species. Histological examination of A. forbesi tissues affected with SSWD showed cuticle loss, vacuolation and necrosis of epidermal cells, and oedema of the dermis, but no consistent evidence indicating the cause of the lesions. Challenge experiments by cohabitation and immersion in infected water suggest that the cause of SSWD is viral in nature, as filtration (0.22 μm) of water from tanks with sea stars exhibiting SSWD did not prevent the transmission and progression of the disease. Death of challenged sea stars occurred 7–10 d after exposure to infected water or sea stars, and the infectivity crossed species (A. forbesi and Pateria miniata) with equal penetrance. Of the 48 stars tested by quantitative real time PCR, 29 (60%) were positive for the SSaDV VP1 gene. These stars represent field-collected sea stars from all geographical regions (South Carolina to Maine) in 2012–2015, as well as stars exposed to infected stars or water from affected tanks. However, a clear association between the presence of SSaDV and SSWD signs in experimental and field-collected A. forbesi was not found in this study

Epigenética, más allá de la Genética Epigenética, más allá de la Genética

Epigenetics is the study of reversible inheritable changes in gene function that occur without a change in the sequence of nuclear DNA and is transmitted from one generation of cells or organisms to the next. The chemical modifications to DNA and its associated proteins help to determine the selective use of genes and influence cell fate. Epigenetic modifications of the genome are involved in regulating many cellular processes. These include embryonic development, X chromosome inactivation and genomic imprinting. Abnormal epigenetic modifications and control can cause disease, including cancer and autoimmune diseases. Identification of inheritable epigenetic patterns such as DNA methylation and histone acetylation has been proposed as a useful marker for the early detection and prognosis of diseases caused by epigenetic errors.<br>La epigenética es el estudio de los cambios heredables reversibles en la función de los genes que ocurren sin cambios en la secuencia de ADN. Las modificaciones químicas del ADN y sus proteínas asociadas determinan la expresión selectiva de genes y su influencia en el comportamiento de las células. Las modificaciones epigenéticas del genoma regulan muchos procesos celulares, tales como el desarrollo embrionario, la inactivación del cromosoma X, la impronta genómica y, la estabilidad de los cromosomas. La alteración de las modificaciones epigenéticas o la pérdida de su control, pueden causar enfermedades como el cáncer y contribuir al desarrollo de enfermedades autoinmunes. Por lo anterior, se ha propuesto que la identificación de los patrones epigenéticos heredables tales como la metilación del ADN y la acetilación de histonas sería una herramienta útil en el diagnóstico y pronóstico de las enfermedades causadas por errores epigenéticos

Sea star wasting disease in asterias forbesi along the Atlantic coast of North America

As keystone species, sea stars serve to maintain biodiversity and species distribution through trophic level interactions in marine ecosystems. Recently, Sea Star Wasting Disease (SSWD) has caused widespread mass mortality in several sea star species from the Pacific Coast of the United States of America (USA) and Asterias forbesi on the Atlantic Coast. A densovirus, named Sea Star associated Densovirus (SSaDV), has been associated with the wasting disease in Pacific Coast sea stars, and limited samples of A. forbesi. The goal of this research is to examine the pathogenesis of SSWD in A. forbesi on the Atlantic Coast of the USA and to determine if SSaDV is associated with the wasting disease in this species. Histological examination of A. forbesi tissues affected with SSWD showed cuticle loss, vacuolation and necrosis of epidermal cells, and oedema of the dermis, but no consistent evidence indicating the cause of the lesions. Challenge experiments by cohabitation and immersion in infected water suggest that the cause of SSWD is viral in nature, as filtration (0.22 μm) of water from tanks with sea stars exhibiting SSWD did not prevent the transmission and progression of the disease. Death of challenged sea stars occurred 7-10 d after exposure to infected water or sea stars, and the infectivity crossed species (A. forbesi and Pateria miniata) with equal penetrance. Of the 48 stars tested by quantitative real time PCR, 29 (60%) were positive for the SSaDV VP1 gene. These stars represent field-collected sea stars from all geographical regions (South Carolina to Maine) in 2012-2015, as well as stars exposed to infected stars or water from affected tanks. However, a clear association between the presence of SSaDV and SSWD signs in experimental and field-collected A. forbesi was not found in this study

Average colony forming units (CFU/mL) of bacteria from Forbes stars with or without signs of SSWD.

<p>Culturable bacteria (individual sample values and average CFU/mL ± SEM) from swabs obtained from stars with visible SSWD lesions (lesion +) and those with no visible lesions (lesion -).</p

List of collected sea star samples.

<p>List of collected sea star samples.</p

Change in SSaDV VP1 copy number in sea stars during progression of SSWD.

<p>Comparison of VP1 copy number per sample in sea stars received from the field in Chaleston, SC. Between the day of arrival (day 1) and day 3 after placement of the stars in quarantine/isolated tanks containing filtered UV-treated artifical sea water. Plots represent individual values for each sample (symbols) as well as the mean (line).</p

List of collected sea star samples.

<p>List of collected sea star samples.</p

Average colony forming units (CFU/mL) of bacteria from Forbes stars with or without signs of SSWD.

<p>Culturable bacteria (individual sample values and average CFU/mL ± SEM) from swabs obtained from stars with visible SSWD lesions (lesion +) and those with no visible lesions (lesion -).</p