Edward W. Daniels

ORIGIN OF THE GOLGI SYSTEM IN AMOEBAE.

SummaryAn electron microscopic study of the Golgi apparatus in the giant amoeba, Pelomyxa illinoisensis, has been presented. Studies of normally feeding, dividing, starving, and refeeding amoebae were made. The major finding is that plasmalemma vesicles, formed via pinocytosis and phagocytosis, either flatten or invaginate and form the cisternae of the Golgi apparatus. Plasmalemma vesicles are also a source of new cisternae during the lifetime of a given Golgi apparatus. The cisternae migrate through the Golgi system, but before being released they either inflate, or segment into smaller vesicles. It is postulated that they later empty into the contractile vacuole and into certain other vacuoles. No evidence was found for the fusion of smooth Golgi vesicles or fringed vesicles of any kind with the plasmalemma.

Pelomyxa palustris Greeff

SummaryThe Pelomyxa palustris amoebae used in this study were multinucleate, herbivorous protozoans. All nuclei within a single organism were similar, but several types of nuclei were seen in different amoeba. These nuclei might represent various stages of mitosis although metaphase and anaphase stages were never seen. Rod-shaped bacteria within vesicles characteristically surrounded the nuclei. Bacterial rods of this as well as another type also occurred within vesicles in the cytoplasm. The nuclear envelope contained annuli and it was covered externally by minute vesicles. Nucleoli and micronucleoli were most frequently located along the inner surface of the nuclear envelope. Clusters of electron-opaque spheroids were found within the nucleoli; sometimes, they existed free in the nucleoplasm. Intranuclear globules of lipidlike material were often seen.Mitochondria, Golgi bodies, contactile vacuoles, and crystal vacuoles were definitely absent in P. palustris. The cytoplasm contained many food vacuoles and clear vacuoles of various sizes. Vacuole-like aggregations, probably containing glycogen, were present.The Pelomyxa palustris amoebae used in this study were multinucleate, herbivorous protozoans. All nuclei within a single organism were similar, but several types of nuclei were seen in different amoeba. These nuclei might represent various stages of mitosis although metaphase and anaphase stages were never seen. Rod-shaped bacteria within vesicles characteristically surrounded the nuclei. Bacterial rods of this as well as another type also occurred within vesicles in the cytoplasm. The nuclear envelope contained annuli and it was covered externally by minute vesicles. Nucleoli and micronucleoli were most frequently located along the inner surface of the nuclear envelope. Clusters of electron-opaque spheroids were found within the nucleoli; sometimes, they existed free in the nucleoplasm. Intranuclear globules of lipidlike material were often seen.

Micrurgical Studies on Irradiated Pelomyxa

The comparative effects of x rays, gamma rays, fission neutrons, and ultraviolet radiation on the giant amoeba P. illinoisensis are shown. Particular attention is given to the percentages of survival and length of life after various exposures. Major emphasis is placed upon the therapeutic value of nonirradiated protoplasm and some of its centrifuged portions following a special method of microinjection known as fusion. Whole protoplasm, as well as heavy portions of centrifuged amoebae, prevent radiation sickness and death after injection into supralethally irradiated amoebae. On the other hand, light portions of nonirradiated, centrifuged amoebae progressively lose this capacity as the ccntrifugal force is increased. Nuclei are not necessary components of therapeutic portions. Fission neutron as well as ultraviolet radiation bring about the inactivation of the therapeutic component in nonirradiated protoplasm that otherwise prevents death in supralethally x-irradiated amoebae. Implications of these findings are discussed.

Starvation effects on the ultrastructure of amoeba mitochondria

SummaryMitochondria in non-starved giant amoebae, Pelomyxa carolinensis, contain tubules lying at random in the matrix. Many mitochondria in starved amoebae have enlarged tubules aligned in a zigzag pattern. Tubules within the zigzag region are separated by very little matrix material. Some of these altered mitochondria are found in 70% of amoebae starved for only 24 hours, and in nearly all P. carolinensis starved for 8 days or longer. The percentage of such altered mitochondria increases from zero in most well-fed amoebae, to about 60% after two weeks of continuous starvation. Most P. carolinensis starved at 25° C survive less than three weeks. Microfilament bundles are observed in the matrix of some mitochondria in amoebae starved for more than two days.

Nucleopores of the giant amoeba, Pelomyxa carolinensis

SummaryAs shown in tangential sections of Pelomyxa carolinensis nuclei, there are many pores, each with a surrounding annulus. Each annulus is composed of 8 subannuli or satellites, plus one to three central granules. Each satellite is an electron opaque mass (of much smaller opaque particulates) about 25 nm in diameter. The outer diameter of each annulus is about 115 nm while the inner, or pore diameter, is about 65 nm. The pores occur at distances averaging 185 nm from center to center. Frequently, delicate filaments connect adjacent satellites, and the central granule with the satellites. As seen in cross sections of the nucleus, nucleopores are formed by the fusion of the inner and outer nuclear envelope membranes. The pore appears as a gap, spanned by a delicate diaphragm anchored to the nuclear envelope where its two membranes are fused. Possible functions of the pore-annulus complexes are discussed.

RESCUE OF SUPRALETHALLY X-IRRADIATED AMOEBAE WITH NONIRRADIATED CYTOPLASM.

The radiosensitive amoeba, Pelomyxa illinoisensis, dies 4 to 6 days after supralethal exposure to x-rays (30 kR), and cell division rarely occurs before death. Irradiated amoebae survive and reprod...

Separation techniques for auto shredder residue

Disposal of automobile shredder residue (ASR), remaining from the reclamation of steel from junked automobiles, promises to be an increasing environmental and economic concern. Argonne National Laboratory (ANL) is investigating alternative technology for recovering value from ASR while also, it is hoped, lessening landfill disposal concerns. Of the ASR total, some 20% by weight consists of plastics. Preliminary work at ANL is being directed toward developing a protocol, both mechanical and chemical (solvent dissolution), to separate and recover polyurethane foam and the major thermoplastic fraction from ASR. Feasibility has been demonstrated in laboratory-size equipment. 10 refs., 2 figs.

The Effects of Weightlessness on PelomyxaII. Nuclear and Cellular Division

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Stratification within centrifuged amoeba nuclei

SummaryTwo species of large, fresh water amoebae were ultracentrifuged and studied with the electron microscope. Emphasis was placed on the stratification of the nucleoplasm, including nucleoli, within the confines of the nuclear envelope during interphase. Three major strata were found in the nuclei of both amoeba species, namely the centripetal nucleoplasm, the middle chromatin stratum, and the centrifugal nucleolar mass. In the highly radioresistant A. proteus, the nucleolar mass separated into a centripetal electron-opaque layer and a centrifugal electron-lucent layer. The latter layer appears to be missing from the radiosensitive P. illinoisensis. The nature of these nucleolar layers and their possible relationship to differences in radiosensitivity between the two species of amoebae is discussed. The contents of the heavier of the two nucleolar layers in A. proteus might be resistant to radiation damage and may possess radiorestorative capacity.

RECOVERY OF SUPRALETHALLY X-IRRADIATED AND NITROGEN MUSTARD (HN2)-TREATED AMOEBAE.

SummaryLarge multinucleated amoebae, Pelomyxa illinoisensis, irradiated with 30 kR of x-rays (a supralethal dose), died after 4 to 5 days without dividing. Amoebae treated with supralethal doses (0·1 or 0·2 mg/ml. for 1 hour) of nitrogen mustard (HN2; Mustine HCl; Mustargen HCl; CH3N(CH2CH2Cl)2HCl), died several days after treatment without cell division. When protoplasm from HN2-treated amoebae was injected by fusion into x-irradiated amoebae, the composite organisms reproduced and permanently recovered. Cytoplasm from HN2-treated donors also induced recovery.HN2-treated amoebae, unlike x-irradiated amoebae, did not recover after the injection of cytoplasm from non-treated, unirradiated amoebae. Supralethal doses of actinomycin D, puromycin, tetracycline, oxytetracycline, 2,4-dinitrophenol, sodium fluoroacetate, or sodium fluoropyruvate prevented the donor protoplasm from restoring x-irradiated amoebae. We interpret these and previous results to indicate that polyribosomes and their larger subunits, from...