English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Transmission electron microscopy gives first evidence of virus-like particles (VLP) in the cytoplasm of Elphidiuni excarraturn clavatum from the western Baltic Sea. The particles are found mostly in groups or in microcrystalline arrays, in young chambers only The VLP are about 100 nm in size, non-enveloped, containmg an electron-dense core in a translucent intermediate capsid region. Based on digitalized area measurements, VLP-infected individuals are characterized by a significant increase in cytoplasmic vacuoles. Lipid inclusions are drastically reduced by 4 0 . 7 " ~ The role of foraminiferans as potential vectors of virus diseases of other aquatic organisms is discussed. Foraminifera are Granuloreticulosa protozoans with agglutinated or calcified test inhabiting all marine environments. Viruses and virus-like particles (VLP) have rarely been found in protozoans and have never been reported from Foraminifera (Lauckner 1980). Franca (1976) described VLP of 35 nm in diameter in the flagellate Gyrodinium resplens from the west coast of Portugal. Teras et a1 (1977) studied the interactions between several protozoans and virus types. No interactions occurred in 80 % of those combinations, but particular protozoan species may be indifferent to viruses as far a s inactivation or multiplication are concerned. Kesa & Teras (1977) mentioned protozoans as possible potential sources of virus infections for aquatic animals. Viruses were found in Entamoeba histolytica and Plasmodium sp. (Nienhaus 1985) but were not classified by their morphology. Individuals of Elphidium excavatum clavatum were collected in June 1987 from a 18 m deep station in the western Baltic Sea (54'32' N, 10'25' E), Federal Republic of Germany. They were fixed for 3 h in a solution of 2.5 O/O glutaraldehyde in seawater, postfixed for 3 h in 2 % osmium tetroxide and decalcified in 0.2 M EDTA (ethylenedinitrilotetra acetate). After dehydration in a graded ethanol series, the specimens were transferred to propyleneoxide and ERL. Ultrathin sections were cut with a Reichert Ultracut E , stained with 1 % uranylaceQ Inter-ResearchPrinted in F R. Germany tate and 0.5 O/O lead citrate. The sections were examined in a Siemens Elmiskop 101. The cytoplasmic compartments were area-measured with a cursor on a graphic table using a Zeiss digitalizer MOP 80 on a n average of magnified nlicrographs (30 X 20 cm). The micrographs were selected from 5 different ultrathin sections taken from each of 2 young virus-infected and 5 young noninfected chambers of E. excavatum clavatum. The VLP are hexagonal in profile and measure 100 nm (f 3 nm) between opposite vertices. The typical VLP is characterized by an electron-dense core of 65 nm in size and an electron-translucent intermediate region which is included in an icosahedral nonenveloped capsid (Fig. 1B). The occurrence of VLP is restricted to very young chambers. Attempts at detection of VLP in cytoplasm of other chambers were unsuccessful. The particles rarely appear singly, but mostly in groups attached to intracytoplasmic inclusions, or in microcrystalline arrays (Fig. lA , C) . Digitalized measurements of cell compartments, based on micrographs of infected and non-infected foraminiferan individuals, indicate obvious morphological differences (Fig. 2A, B). In infected specimens, number and area of lipid inclusions are drastically reduced (9.8 compared to non-infected individuals (16.6 pm2; Table 1). This tendency is much less pronounced and not significant for isolated chloroplasts. In contrast, area of cytoplasmatic vacuoles is significantly increased (3 1.4 %). Assuming that the results gained from investigations of non-infected specimens reflect a 'normal' condition, the mentioned morphological characteristics of infected individuals might indicate viral cytopathological effects. Pathological variations in test morphology of infected specimens could not be observed. Elston (1979) found VLP-induced lesions in larval Pacific oysters, associated with electron-lucent vacuoles and intracytoplasmic inclusions in the velar Dis. aquat. Org. 4 : 233-236, 1988

Virus-like particles and cytopathological effects in Elphidium excavatum clavatum, a benthic foraminiferan