Irradiation of Parts of Individual Cells II. Effects of an Ultraviolet Microbeam Focused on Parts of Chromosomes

Uretz, Robert B.; Bloom, William; Zirkle, Raymond E.

doi:10.1126/science.120.3110.197

Cited by 79 publications

(19 citation statements)

References 3 publications

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“…7B). "Paling" of microirradiated parts of chromosomes was reported in experiments on cells grown in tissue culture while they were being observed under phase contrast optics (Uretz et al, 1954). In our experiments, the temperature of the water in the chamber containing the animal was kept low in order to anesthesize the animal.…”

Section: Spontaneous Anomaliesmentioning

confidence: 91%

Anomalous anatomy of identified neurons in the larval prawn: spontaneous and induced by microlesions

Friedlander¹,

Levinthal²

1982

J. Neurosci.

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The abdominal ganglia of the prawn Macrobrachium rosenbergii undergo developmental changes of fundamental interest between the time of hatching and metamorphosis. These changes include an increase in cell numbers and changes in the connectivity between identified neurons. The giant motoneurons involved in the escape response, which form a syncytium in the adult, are observed as separate neurons with crossed axons in early larvae.Anomalous growth and connections of identified neurons were studied in order to gain some understanding of the rules and mechanisms governing normal development. Spontaneous anomalies included: supernumerary axons and abnormal axonal trajectories. The plasticity and specificity of identified neurons were studied by following the anatomical effects of deletions of giant neurons. Microlesions were inflicted reproducibly by means of a focused beam of visible and ultraviolet light. Within a day, irradiated cell bodies are eliminated; complete disappearance of the axon takes about 10 days, indicating that the remarkable ability of some invertebrate neurons to survive without a soma is not present in the larval prawn. As a result of the removal of an axon, the most common effect found in central connections was the absence of the collaterals or axons deprived of their targets. No collateral sprouting was detected in the central nervous system. In about a third of the ganglia where a giant motoneuron was killed and structure was analyzed 2 or more weeks after irradiation, anomalous connections were found. They usually involved contacts between an interneuron deprived of its normal target and the contralateral motoneuron which remained intact. The restricted types of anomalies observed support the notion of a hierarchical order in the rules governing formation of central synapses, in which neuron type ranks higher than laterality.Decapod crustaceans, such as crayfish and lobsters, have been animals of choice of neurobiologists for many years. The main reason for this is their relatively simple nervous system; the fact that several of their cells are remarkably large and can be identified according to a variety of anatomical and physiological criteria is also a contributing factor in their choice. The giant Malaysian prawn, Macrobrachium rosenbergii, shares the advan-' This work was supported by National Institutes of Health Grants NS 09821 and RR-00442.We thank D. Soroker and M. Spira for kindly letting us know details of their unpublished observations on the connectivity of the giant fibers of the adult prawn. We also thank A. F.

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Section: Spontaneous Anomaliesmentioning

confidence: 91%

Anomalous anatomy of identified neurons in the larval prawn: spontaneous and induced by microlesions

Friedlander¹,

Levinthal²

1982

J. Neurosci.

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“…to recent advances in techniques for the selective ultraviolet-irradiation of restricted areas of living cells, a considerable amount of work has been contributed by several authors particularly to the behavior of the chromosomes (cf., Uretz et al 1954, Zirkle et al 1956, Izutsu 1959, Takeda and Izutsu 1961, Wada and Izutsu 1961. Most of these studies, however, have been carried out on cells at pro-, meta-, and anaphases, a very few papers being referred to in the literature with respect to the effect of irradiation on telophasic cells.…”

Section: Thanksmentioning

confidence: 99%

Unusual Movement of the Daughter Chromosome Group in Telophasic Cells Following the Exposure to Ultraviolet Microbeam Irradiation

Nakanishi¹,

Kato²

1965

CYTOLOGIA

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“…Compared to the early ablation studies that used UV-lamps [18], newer laser-equipped microscopes have enabled faster and more finely targeted ablations, making it possible in certain large cells (e.g., newt lung or PtK cells) to micro-surgically sever the centromeric chromatin connecting two sister kinetochores [41], or to selectively destroy one sister of a pair [42]. If a kinetochore moving poleward during metaphase is micro-surgically freed from its sister, it continues moving poleward ( Figure 5a).…”

Section: Kinetochores Can Either Be Actively Pulling Poleward or Passmentioning

confidence: 99%

Anaphase A: Melting Microtubules Move Chromosomes toward Spindle Poles

Cl¹

2017

Preprint

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Abstract:The separation of sister chromatids during anaphase is the culmination of mitosis and one of the most strikingly beautiful examples of cellular movement. It consists of two distinct processes: Anaphase A, the movement of chromosomes toward spindle poles via shortening of the connecting fibers, and anaphase B, separation of the two poles from one another via spindle elongation. I focus here on anaphase A chromosome-to-pole movement. The chapter begins by summarizing classical observations of chromosome movements, which support the current understanding of anaphase mechanisms. Live cell fluorescence microscopy studies showed that poleward chromosome movement is associated with disassembly, or 'melting' of the kinetochore-attached microtubule fibers that link chromosomes to poles. Microtubule-marking techniques established that kinetochore-fiber disassembly often occurs through a 'pac-man' mechanism, where tubulin subunits are lost from kinetochore-attached plus ends and the kinetochore appears to consume its microtubule track as it moves poleward. In addition, kinetochore-fiber disassembly in many cells occurs partly through 'flux', where the microtubules flow continuously toward the poles and tubulin subunits are lost from minus ends. Molecular mechanistic models for how load-bearing attachments are maintained to disassembling microtubule ends, and how the forces are generated to drive pac-man and flux-based movements, are discussed.

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Irradiation of Parts of Individual Cells II. Effects of an Ultraviolet Microbeam Focused on Parts of Chromosomes

Cited by 79 publications

References 3 publications

Anomalous anatomy of identified neurons in the larval prawn: spontaneous and induced by microlesions

Anomalous anatomy of identified neurons in the larval prawn: spontaneous and induced by microlesions

Unusual Movement of the Daughter Chromosome Group in Telophasic Cells Following the Exposure to Ultraviolet Microbeam Irradiation

Anaphase A: Melting Microtubules Move Chromosomes toward Spindle Poles

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