Walton, L. B.

The Ohio Journal of Science

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CELL DIVISION AND THE FORMATION OF PARAMYLONIN EUGLENA OXYURIS SCHMARDA.L. B. WALTON.The method of reproduction in Euglena oxyuris Schmardahas not been observed, while the characteristic manner andthe time element involved in the formation of the constituentparts of the cell is also of some interest. Therefore, the followingnotes made in connection with some uncompleted studies on thelife cycle of Euglena are presented.Of the forty or more species constituting the genus, E. oxyurisSchmarda is by far the largest, often attaining a length of approxi-mately 500/U-. In the study mentioned, several of the smallerspecies of Euglena had been observed by the writer, to encyst andafter repeated divisions pass through an apparent sexual stage,in consequence of which it was desirable to cheek the results witha larger form, permanent preparations of which could be moreeasily made. Therefore, several specimens of E. oxyuris weretransferred from a culture to a lens paper aquarium, the marginsof which were closed by paraffin oil to prevent evaporation andplaced under observation, Feb. 4, 1906. No reproductive pro-cesses similar to those in the smaller species mentioned wereobserved, but several in the process of division were noted andstudied with the 1-12 immersion objective. The characteristicorgans of the species (Fig. 1, A) are the oval nucleus (n), thelarge anterior (p1) and posterior (p2) paramylon granules, thestigma (s), reservoir (r), pharynx (p) and chloroleucites (c).The figures are all based on camera lucida drawings.On Feb. 6, at 10:03 A. M., a single individual (Fig. 1, B) wasobserved much broader anteriorly than the normal form and inwhich the nucleus had approached the stigma while the anteriorparamylon granule occupied very nearly the normal positionof the nucleus. It was not until 1:45 P. M. (Fig. 1, C) that thedivision of the stigma was observed, the nucleus in the meantimehaving become obliquely elongated, and the anterior paramylongranule having moved down to a position beside the posteriorgranule. At 3:35 P. M. (Fig. 1, D) division had so far progressedthat the anterior fourth of the individual—individuals?— wereseparated, the two nuclei being almost distinct. At 4:15 P. M.(Fig. 1, E) longitudinal division was nearly complete and thetwo nuclei were moving slowly posteriorly to their normal position.At the same time a peculiar phenomenon was taking place inconnection with the two paramylon granules. The protoplasmcontaining the granule of the individual on the left would rapidlyflow posteriorly, so that the granule was actually in the posteriorend of the individual on the right as indicated by the solid arrow.44945O The Ohio Naturalist. [Vol. XV, No. 4,The time consumed was 20 seconds. Then the reverse flow-occurred and the protoplasm containing the granule of the indi-vidual on the right would flow to the left as indicated by thedotted arrow. It would seem at times as if an observer couldscarcely refrain from concern as to the probability that one indi-vidual would inherit all the paramylon. At 4:25 P. M. (Fig.l, F)Fig. 1. (x 500). Cell division in Englena oxyuris Schmarda and For-mation of Paramylon. p = pharynx. s = stigma. p* = anterior paramylongranule. n = nucleus. p2 = posterior paramylon granule. c = chloroleucites.the process of division was completed, the nuclei having movedposteriorly and the individuals appearing normal in every waywith the exception that each lacked the large anterior paramylongranule. Observations were made periodically the folio ingday with the expectation of noting the development of the newFeb., 1915.] Paramylon in Euglena Oxyuris Sclimarda. 451granule. It was, however, not until the succeeding day at 9:00A. M. (Fig. 1, G), approximately 40 hours from the time of thecomplete division that an irregular, but distinct granule becamevisible. This gradually increased in size, but had not attainedits full development at the end of the day, when the observationswere brought to a close. The other twin individual had in themeantime disappeared.There are two factors, however, which may have been instru-mental in delaying the formation of the anterior granule, thelowering of the room temperature nearly to freezing at night, andthe possible lack of the necessary nutrient material in the smallclosed lens paper aquarium.While the synthesis of "paramylon," a term first suggested byGottleib, (1851) because of the similarity in chemical compositionto amylon (starch), normally occurs in connection with thechloroleucites present in the Euglenidae, the question as to itspossible free formation as an assimilation product of the proto-plasm has long been one of interest and one concerning which nodefinite statement may up to the present time be made. Themode of formation of the anterior paramylon granule in Euglenaoxyuris is extremely suggestive, however, that the result is due tothe activities of the protoplasm quite independently of thenumerous small chloroleucites present. Distributed irregularlyas they are throughout the cell body, it seems difficult to believethat their products should unite to make a structure so definitein form and position.The time taken for the division of the individual was 63^hours, with the assumption that the condition as figured in " B "had occupied only a brief period. Keuten (1895) notes the timeof division in Euglena virdis as 3-4 hours. There are apparentlyno notes concerning the time necessary for division among otherrelated forms, although Doflein (1911) gives a comparativetable for various species of Protozoa. The factor is undoubtedlya variable one and largely dependent on the surrounding conditionsparticularly temperature and nourishment.BIBLIOGRAPHY.BUTSCHLI, O., 1906. Beitrage zur Kenntnis des Paramylon. Archiv furProtistenkunde, p. 197, 1 Taf.DAXGEARD, P. A., 1902. Recherches sur les Ewgleniens. Botaniste, ser. 8.DOFLEIN, F., 1911. Lehrbuch der Protozoenkunde.GOTTLEIB, J., 1851. Ueber eine neue mit Starkemehl isomere Substanz.Ann. d. Chemie u. Pharmacie. Bd. 75, p. 51.KEUTEN, L., 1895. Die Kernteilung von Euglena viridis. Zeit. wiss. Zool.V. 60, p. 215.KLEBS, G., 1881. Organisation einiger Flagellatengruppen u. ihre Bezie-hungen zu Algen u. Infusiorien. Untersuch. bot. Inst. Tubingen, Bd. 1.SCHMITZ, F., 1883. Die Chromatophoren der Algen, Bonn.SCHMITZ, F., 1884. Beitrage zur Kenntnis der Chromatophoren. Pring.Jahrb. Bd. XV, p. 1.OLTMANNS, F., 1905. Morphologie und Biologie der Algen, Bd. 2, p. 151.Kenyon College, Gambier, Ohio, Dec. 24, 1914.

Cell Division and the Formation of Paramylon in Euglena Oxyuris Schmarda

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Cell Division and the Formation of Paramylon in Euglena Oxyuris Schmarda

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