Calcification of Spirostomum ambiguum

SYNOPSIS. A method is described for cultivation of large numbers of Spirostomum ambiguum , calcified intracellularly with hydroxyapatite (bone salt deposits). The structure and activity of living animals at various stages of calcification is described and also illustrated with unstained and silver impregnated ciliates. A suitable modification of von Kossa's method for localization of insoluble phosphate deposits is given.     

Nuclear Behavior of Spirostomum ambiguum During Conjugation with Special Reference to Macronuclear Development*

SYNOPSIS. During conjugation in Spirostomum ambiguum, the micronuclei divide thrice before synkaryon formation and 20 times thereafter. During the first meiotic division 18-24 bivalents, each about 0.5 μ or less appear on the spindle. They separate and pass to the poles. The details of the 2nd and 3rd prezygotic divisions and synkaryon formation by reciprocal exchange of gametic nuclei resemble those described for other ciliates in the literature. The synkaryon divides twice resulting in 4 nuclei; 2 of them become micronuclei and the remaining 2 macronuclear anlagen. The micronuclei enter into division, but this division is arrested in metaphase. The chromosomes in the macronuclear anlagen resemble those appearing in the Ist meiotic division in shape and size. In their maximum stage of development the macronuclear chromosomes are at least 3-4 times larger than those appearing in the arrested micronuclear metaphases in the same cell. There is no banding pattern of the chromosomes and therefore the possible extent of polyteny is difficult to evaluate. The chromosomes duplicate 3-4 times resulting in about 200–250 before they become indistinct as separate entities. Spirostomum is the only nonhypotrichous ciliate in which these cytologic features are described.     

Calcium and Phosphorus Accumulation in Spirostomum ambiguum

SYNOPSIS. Spirostomum ambiguum is known to contain Ca phosphate as apatite. Tracer experiments with ³²P and ⁴⁵Ca showed that much of the Ca that enters the animal is inexchangeable. About 20% exchanges in the 1st few days but after 42 days only 50% of the original isotope content has been lost. This process seemed independent of temperature, Ca and K concentration, and of whether the animals were starved or fed. It is postulated that the firmly bound Ca is in the form of apatite. By use of both isotopes simultaneously it was shown that some of the Ca uptake was linked with phosphate uptake. However, there appear to be at least one, probably 2 compartments of Ca uptake independent of phosphate uptake. The experiments suggest there being in all 3 compartments of Ca uptake: one firmly bound as apatite; one slightly less firmly bound in some other form (perhaps carbonate); and a last freely exchangeable fraction. The P was found in 2 compartments: one bound to Ca; the other freely exchangeable.
Autoradiography and histochemical tests localized the Ca phosphate deposits in the endoplasm, the ectoplasm and nuclear material being free of such deposits. Identification of these deposits in electron micrographs is discussed. It is suggested that these deposits may be waste products possibly derived from mitochondri***al accumulations.     

Fine Structure of Mitochondria of Spirostomum ambiguum as Seen in Sectioned and Negatively-Stained Preparations*

SYNOPSIS. Comparisons are made between sectioned and negatively-stained mitochondria of the ciliate Spirostomum ambiguum. Particulate elements 70–80 A in diameter are associated with the surface of tubular cristae of negatively-stained and disrupted mitochondria; such particles are not seen in sectioned mitochondria fixed in various ways. As measured in sectioned material, the inner mitochondrial membrane forming the tubular cristae is about 100 A thick, while the outer mitochondrial membrane is about 50 A thick and is the more labile of the 2.     

Spirostomum ambiguum as a bioindicator of aquatic environment pollution

Express-methods based on functional and morphological features of the genus Spirostomum have been applied for estimation of the effect produced by chemical toxicants, γ-radiation, electromagnetic emission, and homeopathic drugs on the aquatic environment. The experiments have shown that Sp. ambiguum is a very useful indicator for the bioassay of low-intensity physical and chemical pollution in the aquatic environment.     

A new low cost microbiotest with the freshwater ciliate protozoan Spirostomum ambiguum

This paper reports on preliminary experiments on the controlled culturing of the freshwater ciliated protozoan Spirostomum ambiguum, as a first step in the development of a new low cost microbiotest, to complement the limited battery of standardized cost-effective toxicity tests presently available, with a representative of unicellular biota.Three strains of S. ambiguum originating from France and Poland respectively, have been grown in natural as well as in reconstituted waters, on several types of inert diets and in different temperature and light conditions.The best results in terms of survival and reproduction of the ciliates, leading to a standard recipe for stock culturing, were obtained at 20 °C, in reconstituted Volvic water and on a diet of oat flakes supplemented with dried leave powder as vegetal adjuvant, with weekly renewal of the medium and food. An average generation time of 4 days was obtained in the latter set of stock culturing conditions.     

Electron microbeam analysis of calcium distribution in the ciliated protozoan, Spirostomum ambiguum.

Electron microprobe analyses of calcium distribution in the ciliated protozoan, Spirostomum ambiguum, indicated several calcium rich sites. One site was an endoplasmic distribution of calcium coincident with phosphorus which corroborates previous findings of hydroxyapatite deposits within Spirostomum. These apatite deposits were distributed throughout the endoplasm, but not within the nuclei or the contractile vacuole. Calcium was also detected within the cortical region. Cortical calcium was in greater concentration in the anterior portion of the organism and decreased towards the posterior end (region containing the contractile vacuole). Phosphorus and potassium were also detected as gradients from the anterior end, whereas magnesium was detected in the same density throughout the cortical region. Line scans of cortical regions suggested (1) distributions of calcium within mitochondria and/or vesicles, and (2) calcium associated with bundles of microfilaments.     

Electron Microscopy of the Longitudinal Fibrillar Bundle and the Contractile Fibrillar System in Spirostomum ambiguum

SYNOPSIS. A study of the 'longitudinal fibrillar bundle' (LFB) and the 'contractile fibrillar system' (CFS) of a large protozoan ciliate, Spirostomum ambiguum , has been performed by means of an electron microscope. A system of sub-pellicular fibrils has been newly found and its function is discussed. Each LFB runs parallel with a longitudinal row of ciliary bases. It seems to be identical with the so-called kinetodesma. It is composed of tubular fibrils arranged in layered sheets, each of which contains 13 to 35 fibrils with the same diameter as the intra-ciliary fibrils and has a close connection to each of the ciliary bases. The CFS lies on a transitional plane between ectoplasm and endoplasm of the organism and forms a cobweb-like system of myofibrils as a whole. It stands in an intimate relationship with a characteristic vacuolar system. In a peristomial field, the fibrous structures are interrupted and somewhat thickened. A sub-pellicular system is composed of minute fibrils 20 to 26 mμ in diameter. The fibrils run parallel with each other in an antero-posterior direction, immediately beneath the inner pellicular membrane.     

Contraction of protoplasm. I. Cinematographic analysis of the anodally stimulated contraction of Spirostomum ambiguum

Electrically stimulated contraction of Spirostomum ambiguum was investigated by high speed cinematography (up to 6,000 pps). Contraction is completed in about 4 msec following a latent period of up to 30 msec. Reduction in length during contraction followed a sigmoid curve, and final length was about 50% of the original length. Contraction always started at the end of the animal directed towards the anode. When the length of each half was measured separately, it was found that the cathodal end lagged about 1 msec in all cases observed. Rate of contraction was increased when the external calcium contraction was increased, and was decreased in Ca-free and K-free solutions, but was unchanged in K-rich solutions. These results are interpreted in terms of contraction being associated with a relative increase of calcium bound to the contractile protein. The differential migration of potassium and calcium ions in an electric current would result in a temporary lowering of K⁺ at the anodal end of the animal, hence a relative rise would take place in the Ca⁺⁺ available for binding. The results of experiments using changed calcium and potassium concentrations can be explained by this hypothesis which is in general agreement with modern work on muscle contraction and relaxation.     

Spontaneous motional activity of paramecium Spirostomum ambiguum after gamma-irradiation in a broad variety of dose as a bioassay

The spontaneous motional activity of paramecium Spirostomum ambiguum Ehrbg. has high sensitivity to the gamma-irradiation. The increase of this parameter has been observed just after irradiation in the 0.1 Gy. It is approximately on the similar level (about 35% below control) in a broad variety of doze (to 850 Gy inclusive). After that the dozes 1000-1500 Gy has been obtained, the effect became stronger. The present result has been interesting in the question of the behavior's reaction unicellular using in the indication of the radioactivity contamination of the aquatic aria. And also it is actual in the common problem of the irradiation activity on the biota.     

Uptake and release of 45Ca by Myxicola axoplasm

The binding and release of 45Ca by axoplasm isolated from Myxicola giant axons were examined. Two distinct components of binding were observed, one requiring ATP and one not requiring ATP. The ATP- dependent binding was largely prevented by the addition of mitochondrial inhibitors, whereas the ATP-independent component was unaffected by these inhibitors. The ATP-independent binding accounted for roughly two-thirds of the total 45Ca uptake in solutions containing an ionized [Ca2+] = 0.54 microM and was the major focus of this investigation. This fraction of bound 45Ca was released from the axoplasm at a rate that increased with increasing concentrations of Ca2+ in the incubation fluid. The ions Cd2+ and Mn2+ were also able to increase 45Ca efflux from the sample, but Co2+, Ni2+, Mg2+, and Ba2+ had no effect. The concentration-response curves relating the 45Ca efflux rate coefficients to the concentration of Ca2+, Cd2+, and Mn2+ in the bathing solution were S-shaped. The maximum rate of efflux elicited by one of these divalent ions could not be exceeded by adding a saturating concentration of a second ion. Increasing EGTA concentration in the bath medium from 100 to 200 microM did not increase 45Ca efflux; yet increasing the concentration of the EGTA buffer in the uptake medium from 100 to 200 microM and keeping ionized Ca2+ constant caused more 45Ca to be bound by the axoplasm. These results suggest the existence of high-affinity, ATP-independent binding sites for 45Ca in Myxicola axoplasm that compete favorably with 100 microM EGTA. The 45Ca efflux results are interpreted in terms of endogenous sites that interact with Ca2+, Cd2+, or Mn2+.