Sarcodine

Sarcodinele reprezintă grup de protiste asemănătoare animalelor care cuprinde: amibele, radiolarii și foraminiferele. Hrănirea este exclusiv heterotrofa, trăiesc libere în mediul acvatic și sunt unicelulare. Au pseudopode cu rol în deplasare și înglobarea particulelor de hrană.Au respirație aeroba ,iar respirație anaeroba la sarcodinele parazite.Reproducerea este asexuata prin diviziune directa.

sarcodine

Recent analyses of the small subunit ribosomal DNA (srDNA) from dinoflagellate symbionts of cnidaria have confirmed historical descriptions of a diverse but well-defined clade, Symbiodinium, as well as several other independent symbiont lineages (Rowan 1991; Rowan and Powers 1992; Sadler et al. 1992; McNally et al 1994). Dinoflagellates also occur as intracellular symbionts in a number of pelagic protistan taxa, but the srDNA of these symbionts has not been examined. We analyzed the srDNA sequences of the symbiotic dinoflagellates from four planktonic foraminiferal species and six radiolarian species. The symbionts from these sarcodines formed two distinct lineages within the dinoflagellates. Within each lineage, symbionts obtained from different host species showed few, if any, srDNA sequence differences. The planktonic foraminiferal symbionts were most closely related to Gymnodinium simplex and the Symbiodinium clade, whereas the radiolarian symbionts were most closely related to the dinoflagellate symbiont from the oceanic chondrophore, Velella velella. Therefore, although the dinoflagellate symbionts of foraminifera appear to be a sister taxon of the symbionts from benthic foraminifera and invertebrates, the symbionts of radiolaria are distinct and arose from an independent lineage of dinoflagellate symbionts that shares common ancestry with the symbiont of at least one pelagic metazoan. The lack of srDNA variability within the sarcodine symbiont lineages suggests that coevolution of host and symbiont has not occurred.

The sarcodines include the naked forms (amebas) and forms with perforated shells, or tests, through which pseudopods may be extended. Best known of the shelled forms are the foraminiferans, with calcium carbonate shells.

The diagram is showing a sarcodine because it has a pseudopod. Sarcodine is a protozoa. These organisms exhibit cytoplasm and use a temporary extension cytoplasmic extension called as pseudopodium, which helps in locomotion and feeding. The shape of these organisms is typically circular or irregular. They may contain more than one nucleus. The food which adheres to the surface of the cell is trapped by the pseudopodium and is digested by the vacuoles.

A species of large,testate sarcodine is a conspicuous component of the shallow benthos inMcMurdo Sound and elsewhere inthe Antarctic. On the basis of its general appearance, this protist waspreviously identified as Gromia cf. oviformis (Filosea:Protista)(Heron-Allen and Earland 1922; DeLaca 1986; Kiest 1993; Gooday, Bowser,and Bernhard in press). As noted by Jepps (1926) andArnold (1982), however, gross morphological characters to differentiatepotential congeners within this obscure group are rare;detailed autecologic information is also lacking.

The diagram is showing a sarcodine because it has a pseudopod. Sarcodine is a protozoa. These organisms exhibit cytoplasm and use a temporary extension cytoplasmic extension called as pseudopodium, which helps in locomotion and feeding.

This sarcodine culture is great for demonstrating amoebae structure and locomotion. Optimal medium: Carolina Springwater + Chilomonas + Wheat Seed. Optimal growth temperature: 22 C. Each culture contains enough material for a class of 30 students to prepare wet mount slides.

This sarcodine feeds on the single-chloroplast Spirogyra by attaching to the ends of fragmented strands and pulling out and engulfing the chloroplasts. Optimal medium: Carolina Springwater + Single-Chloroplast Spirogyra. Optimal growth temperature: 22 C.

The most well-known example of a sarcodine is the famous amoeba. Lacking any rigid structure outside of their cell membrane, sarcodines can freely change their shape and form pseudopodia. Sarcodines can live in both freshwater and marine environments. They can reproduce both asexually and sexually, and they are usually free-living. Like mastigophores, sarcodines use pseudopodia to move and capture food. Although the amoeba is generally thought of as lacking any structure, some have shells, and most other types of sarcodines also have shells. One class of sarcodines, the foraminiferans, possess calcareous shells (they are made of CaCO3).

In the final decade of the 20th century, a series of molecular phylogenetic analyses confirmed that Sarcodina was not a monophyletic group. In view of these findings, the old scheme was abandoned and the amoebae of Sarcodina were dispersed among many other high-level taxonomic groups. Today, the majority of traditional sarcodines are placed in two eukaryote supergroups: Amoebozoa and Rhizaria. The rest have been distributed among the excavates, opisthokonts, and stramenopiles. Some, like the Centrohelida, have yet to be placed in any supergroup.[10][48]

The study of the protozoan fauna of insects revealed a number of flagellates, sarcodines and ciliates. In the present text consideration is given only to the genusMonocercomonoides, and three new speciesM. garnhami n.sp. fromPeriplaneta americana, M. ganapatii n.sp. fromGryllotalpa africana andM. qadrii n.sp. from the larva of the dungbeetle,Oryctes rhinoceros are described in detail and are claimed to be new to science on the basis of their size, nuclear structure and the mastigont elements. 041b061a72