The course and mortality of a hematopoietic neoplasm in the soft-shell clam, Mya arenaria

Survival of sarcoma cells from the soft-shell clam Mya arenaria was studied in vltro. Hemolymph was withdrawn from clams with advanced stages of sarcoma and placed in seawater in 'Farley chambers'. Sarcoma cells were exposed for 6 h to different salinitles, temperatures, pH, and copper concentrations. Cell viability was determined using a new trypan blue-safranin staln on permanent monolayer slides. Counts of live and dead cells were made to determine percent mortality. The lethal low salinity was 0.5%; TLso (tolerance limit, 50% mortality) was 1.7'!:.,; and the lethal high salinity was > 35 :'rA<,. Lethal high temperature was 40°C and TL50 was 33.7 "C. Of cells frozen at -20°C for 6 h, 31 % were viable. The lethal low pH was 3.6, but no mortality occurred at pH 4.0 to 9.3. TLso was pH 3.9

Section: Introductionmentioning

confidence: 64%

Section: Introductionmentioning

confidence: 99%

Environmental limits for survival of sarcoma cells from the soft-shell clam Mya arenaria

Sunila¹,

Farley²

1989

“…The development of marine invertebrate cell culture systems could advance the study of DN by potentially allowing isolation and characterization of a viral agent. Determining the temperature range of the RT activity using the PERT assay could lead to a better understanding of the seasonal nature of the disease that has been reported by several authors (Cooper et al 1982, Appeldoorn et aI. 1984, Farley et al 1986, Brousseau 1987, Leavitt et al 1990).…”

Section: Discussionmentioning

confidence: 97%

Soft shell clams Mya arenaria with disseminated neoplasia demonstrate reverse transcriptase activity

House

Kim²,

Reno³

1998

Disseminated neoplasia (DN), a proliferative cell disorder of the circulatory system of bivalves, was first reported in oysters in 1969. Since that time, the disease has been determined to be transmissible through water-borne exposure, but the etiological agent has not been unequivocally identified. In order to determine if a viral agent, possibly a retrovirus, could be the causative agent of DN, transmission experiments were performed, using both a cell-free filtrate and a sucrose gradientpurified preparation of a cell-free filtrate of DN positive materials. Additionally, a PCR-enhanced reverse transcriptase assay was used to determine if reverse transcriptase was present in tissues or hemolyrnph from DN positive soft shell clams Mya arenana. DN was transmitted to healthy clams by injection with whole DN cells, but not with cell-free filtrates prepared from either tissues from DN positive clams, or DN cells. The cell-free preparations from DN-positive tissues and hemolymph having high levels of DN cells in circulation exhibited positive reactions in the PCR-enhanced reverse transcriptase assay. Cell-free preparations of hemolymph from clams having low levels of DN (<0.1% of cells abnormal), hemocytes from normal soft shell clams, and normal soft shell clam tissues did not produce a positive reaction in the PCR enhanced reverse transcriptase assay.

“…The disorders are considered neoplastic in nature and are commonly refc~rred to as hemic neoplasia or disseminated sarcomas, although there is some question as to whether all represent disorders of hemic origin. Where studied in some detail, they are known to be progressive and fatal (Cooper et al 1982, Elston et al 1988a. A retroviral etiology has been claimed for hemic neoplasia in the soft shell clam (Oprandy & Chang 1983, Oprandy et al 1981, but this claim has not yet been substantiated by repetition or further work on other species.…”

Section: Introductionmentioning

confidence: 99%

Progressive development of circulating polyploid cells in Mytilus with hemic neoplasia

Elston¹,

Drum²,

Allen³

1990

The progressive development of hemic neoplasia in Mytilus is described using a flow cytometric method. Two experiments were conducted in order to determine the DNA content and evolution of the disease in individual Mytilus. In disease free individuals, either 1 or 2 populations of circulating cells (G,, and GLd were detected on the basis of relative DNA content, containing multiples of 2.00 to 2.21 haploid (n) DNA content. In mussels with progressive hemic neoplasia, an increase in an apparently polyploid population (measured 5.1 n) occurred in conjunction with a decrease in the proportion of G1, cells. Subsequent to the increase of the 5 . l n population, the formation of a second apparently polyploid population of circulating cells with a mean measured DNA content of 10.ln occurred and increased over time. The presence of these cell populations with these two ploidy levels represented a single population of autonomously replicating polyploid hemocytes in circulation. These polyploid circulating cell popu1,itions correspond 10 morphological changes in circulating cells which are described from hemocytological preparations. In addition, a second, rarer form of the disease. characterized by an Increase of tetraploid neoplastic cells in circulation was observed. The 2 forms of the disease may represent alternative chromosomal lesions resulting from 2 alternative modes of integration of a foreign genome into the host genome. The significance of these findings on the observation of progression of the disease and on hypothetical etiologies is discussed.