Studies on mitochondrial structure and function in Physarum polycephalum. IV. Mitochondrial division cycle.

Kuroiwa, Tsuneyoshi; Hizume, Masahiro; Kawano, S

doi:10.1508/cytologia.43.119

Cited by 32 publications

(14 citation statements)

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“…The mitochondria must be labeled as long as possible during mS in order to label most of the mtDNA molecules. We have reported that the period of mS is approximately 7.5 h (14). However, since the late nuclear S and early mS overlap, distribution of the grain counts over mitochondria is uncertain when cell nucleus is heavily labeled.…”

Section: Discussionmentioning

confidence: 94%

Studies on Mitochondrial Structure and Function in Physarum polycephalum. VIII. Distribution of Mitochondrial DNA Molecules during Mitochondria Division

Kawano

Kuroiwa

1979

Cell Struct. Funct.

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ABSTRACT. Distribution of mitochondrial DNA (mtDNA) molecules during mitochondrial division to daughter mitochondria in the plasmodium of Physarum polycephalum has been determined by light and electron microscope autoradiographical studies. The plasmodium was incubated in a [311]-thymidine solution during the mtDNA synthetic period (mS) to preferentially label one strand each of the mtDNA molecules. Distribution of the labeled strand on successive first and second rounds of replication and division in a nonradioactive medium was determined by quantitative light microscope autoradiographic technique. Results showed that silver grains were always distributed equally over the dividing dumbbell-shaped mitochondrion. In addition, the distribution frequency of the grain counts over the mitochondria followed a Poisson distribution, and the mean value decreased on mitochondrial division. We conclude that mtDNA molecules are distributed at random, but that an equal amount is divided between two daughter mitochondria. Electron microscope autoradiograms of dumbbell shaped and daughter mitochondria showed that the equal distribution of mtDNA molecules could be ascribed to an equal distribution of the mitochondrial nucleus.

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Section: Discussionmentioning

confidence: 94%

Studies on Mitochondrial Structure and Function in Physarum polycephalum. VIII. Distribution of Mitochondrial DNA Molecules during Mitochondria Division

Kawano

Kuroiwa

1979

Cell Struct. Funct.

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“…At each time indicated by an arrowhead, small explants of plasmodium were fixed and observed as described in the Materials and Methods. The upper horizontal row represents the nuclear division cycle (A) and lower horizontal row represents the mitochondrial division cycle (B), as previously reported (15).…”

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confidence: 94%

“…Recent studies with quantitative morphometric methods have demonstrated that morphological changes in mitochondria occur throughout the mitochondrial division cycle (6,10,14,15). Mitochondrial biogenesis must involve not only increased volume and separation of the mitochondrial matrix and cristae, but also duplication and distribution of mitochondrial DNA (mtDNA) (14).…”

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confidence: 99%

“…The samples were dehydrated and embedded in glycol methacrylate (Oken Shoji Co., Tokyo) as described previously (15). Thin sections of approximately one micrometer were cut with a Porter-Blum ultramicrotome.…”

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confidence: 99%

“…The exposure time was 4 weeks. These samples were stained with acid fuchsin by methods described previously (15). A check was made to ascertain that nearly all silvergrains appearing over the mitochondria represented labeled DNA, by the method described previously (15).…”

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confidence: 99%

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Studies on Mitochondrial Structure and Function in Physarum polycephalum. VI. Synthesis and Distribution of Mitochondrial DNA as Revealed by Light Microscope Autoradiography

Kawano

Kuroiwa

1977

Cell Struct. Funct.

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ABSTRACT. The synthesis and distribution of mitochondrial DNA (mt-DNA) were studied by light microscope autoradiography in the plasmodium of Physarum polycephalum. Mitochondria pre-labeled with 3H-thymidine TdR) for 3 h during early mitochondrial S phase (mS) and incubated in nonradioactive medium showed elongated shapes that developed to dumbbellshaped, and the latter form of mitochondria divided. The incorporation of 3H-TdR into mitochondria occurred during mitochondrial growth but terminated before development to dumbbell-shapes, suggesting that they synthesized mtDNA during a limited period of mitochondrial division cycle. In addition, mitochondrial grains counts were reduced remarkably to about half during the late nuclear S phase, suggesting that Physarum mitochondria divided semisynchronously during late nuclear S phase. The distribution of mtDNA prelabeled during early or late mS was determined by the grain distribution of (a) labeling of both poles of dumbbell-shaped mitochondria, and (b) labeling of daughter mitochondria. The results indicated that mtDNA was distributed equally to daughter mitochondria, regardless of time of mtDNA replication.

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Electron-dense Regions in Dividing Mitochondria of a Green Alga, Scenedesmus acutus

Ueda

Noguchi

1993

Annals of Botany

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Studies on mitochondrial structure and function in Physarum polycephalum. IV. Mitochondrial division cycle.

Cited by 32 publications

References 28 publications

Studies on Mitochondrial Structure and Function in Physarum polycephalum. VIII. Distribution of Mitochondrial DNA Molecules during Mitochondria Division

Studies on Mitochondrial Structure and Function in Physarum polycephalum. VIII. Distribution of Mitochondrial DNA Molecules during Mitochondria Division

Studies on Mitochondrial Structure and Function in Physarum polycephalum. VI. Synthesis and Distribution of Mitochondrial DNA as Revealed by Light Microscope Autoradiography

Electron-dense Regions in Dividing Mitochondria of a Green Alga, Scenedesmus acutus

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