Carteria
Carteria Singh & Hanumaiah, 1979 (ref. ID; 7594)
Order Amoebida Kent, 1880: Family Hartmannellidae Volkonsky, 1931 emend. Singh, 1952 (ref. ID; 7594)
[ref. ID; 7594]
Definition; The resting nucleus contains a single Feulgen-negative nucleolus. During mitosis the nucleolus disappears and a spindle with chromosomes arranged as an equatorial plate is formed. Amoebae in locomotion flattened having a thickened pellicle or dermal thickening. The definition of this genus is given under suggested subdivision of genus Thecamoeba. (ref. ID; 7594)
Notes; From Page's (1971) description of the nuclear division in C. orbis, using Feulgen reaction, it can safely be concluded that no 'corps intermediaire' is present in this amoebae at late anaphase, as found in the genus Russellia. Page (1971) has given only a metaphase stage in C. hilla. If it was found that 'corps intermediaire' was present at late anaphase stage, it will have to be transferred to the genus Russellia. At present this amoeba is being retained in Carteria. (ref. ID; 7594)
Type species; Carteria orbis (Schaeffer, 1926) (ref. ID; 7594)
- Carteria bengaliensis Singh, Misra & Sharma, 1981 (ref. ID; 7594 original paper)
- Carteria cordiformis (Carter) (ref. ID; 3497)
- Carteria hilla (ref. ID; 7594)
Syn; Thecamoeba hilla Schaeffer, 1926 (ref. ID; 7594)
- Carteria orbis (ref. ID; 7594)
Syn; Thecamoeba orbis Schaeffer, 1926 (ref. ID; 7594)
Carteria bengaliensis Singh, Misra & Sharma, 1981 (ref. ID; 7594 original paper)
Descriptions
Amoebae on agar surface are smooth and flattened, and no wrinkles could be clearly seen. As the amoebae adhere to the glass surface, their locomotive morphology was studied in hanging drop preparations. During active locomotion they are flattened. In outline they may be oblong, elliptical or elongatedly elliptical. Sometimes a hump-like structure could be seen at the posterior end. Two to four irregularly spaced longitudinal folds could be clearly seen in most of the amoebae. Hyaloplasm region of amoebae is usually crescent-shaped. A temporary division of the anterior end into two lobes was often seen during change of direction. A single nucleus and a contractile vacuole are present in an individual. The diameter of amoebae n rounded condition is ca. 30-50 um. The amoebae did not produce cysts when maintained in culture for more than fifteen months. It is interesting to note that C. bengaliensis was isolated from an air dried soil kept for a few months. No flagellate stage could be produced even after repeated efforts. (ref. ID; 7594)
Resting nucleus: The resting nucleus in the living condition is rounded having a central spherical nucleolus. No chromatic granules could be distinguished. In stained preparations there is a nucleolus and chromatin granules lie near the nuclear membrane. The nucleolus at times contained a central vacuole. (ref. ID; 7594)
Mitotic division: The amoebae become rounded and motionless at the beginning of the nuclear division. (ref. ID; 7594)
- Prophase. The chromatin granules move to the centre of the nucleus and fuse. The nucleolus disappears, probably giving rise to the spindle.
- Metaphase. A band of chromatic material is seen lying at the equatorial plate stage. The spindle, which may be pointed or somewhat globular, does not show clearly spindle fibres. The nuclear membrane persists during metaphase stage. Later it disappears and the band of chromatic material divides into two equal halves.
- Anaphase. The two bands of fused chromosomes move to the two poles. The parts of the spindle which lie between the two bands and the poles stain more deeply and become smaller as the fused chromosomes approach the poles. The amoebae become oval in shape.
- Telophase. The amoeba oval in outline becomes elongated and a constriction appears in the middle producing two daughter individuals. The amoeba has nearly divided into two, each having the nuclear structure as seen in the resting nucleus.
No intra-nuclear or extra-nuclear aster and centrosome could be found at any stage in the mitotis of C. bengaliensis. (ref. ID; 7594)
Remarks
Besides Carteria bengaliensis, the resting nucleus of two other species belonging to the smooth group, C. orbis (Thecamoeba orbis Schaeffer, 1926) and C. hilla (T. hilla Schaeffer, 1926), described by Page (1971, 1977) from marine habitats, has a single central spherical nucleolus. The nucleolus in all three species during mitosis disappears and a spindle with chromosomes arranged as an equatorial plate develops. The distinguishing characters of C. orbis and C. hilla, as given by Page (1977), are briefly given below. The trophozoites of C. orbis during locomotion are flattened with anterior outline more or less semicircular and posterior edge somewhat convex, occasionally nearly straight, never narrowed posteriorly. Usually several dorsal parallel folds extending far anteriorly are present. Hyaloplasm occupies appoximately anterior half of cell with granuloplasm convex anteriorly. The length of amoebae is approximately 11-22 um. The trophozoites of C. hilla during locomotion are flattened having ovate or obovate outline. Posterior end is sometimes tapering with a narrow peak of granuloplasm. Several parallel dorsal folds extending far anteriorly are present. Hyaloplasm in the form of an anteriolateral crescent is fairly deep anteriorly and sometimes extending to nearly the posterior end along sides of narrowed posterior peak of granuloplasm. The length of amoebae is approximately 32-68 um. C. bengaliensis resembles C. hilla in locomotive morphology, although it is somewhat smaller. Its main distinguishing characters are: (1) during locomotion a temporary division of the anterior end into two lobes takes place during change of direction, and (2) dorsal longitudinal folds are irregularly spaced. (ref. ID; 7594)
Type locality
This amoeba has been isolated from a cultivated soil of Birbhum in West Bengal from culture plates incubated at 28 degrees C but not at 37 degrees C. (ref. ID; 7594)
Descriptions
The species appears in fresh and brackish water. (ref. ID; 3497)