Some Problems of Regeneration

Vv, Brunst

doi:10.1086/403396

Cited by 9 publications

(3 citation statements)

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“…On the contrary, I believe that the basic pattern of the regenerate is constituted by differentiated cells and not by interstitial cells. What distinguishes a hydrozoan regenerate from most other regenerating systems is the fact that it never shows a characteristic regeneration blastema consisting of a bulk of undifferentiated cells which more or less synchronously undergo differentiation, as this is the case in regeneration blastemata of amphibians (Luscher, 1955;Brunst, 1961). The basic structure of a hydroid regenerate always consists of differentiated elements originating from the regenerant, undergoing within restricted limits structural and functional transformation, but I am inclined to think that only the younger cells amongst them are capable of doing so, while the old cells are soon to be replaced by interstitial cells acting as 'Ersatz-Zellen'.…”

Section: (B) the Interstitial Cellsmentioning

confidence: 99%

“…It is certainly not higher than in a resting coenosarc tissue and it seems that the multiplication of cells begins only when the regenerate is fully differentiated and enters the phase of growth. Several workers who have dealt with the problem in regenerating amphibians find that mitotic activity starts also relatively late, after the formation of the regeneration blastema (Litwiller, 1939;Chalkley, 1959;Brunst, 1961).…”

Section: (C) the Histodynamics Of Regenerationmentioning

confidence: 99%

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Regeneration in the Hydrozoa

Tardent

1963

Biological Reviews

110

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Summary 1. This article reviews the present state of knowledge on regeneration in the Hydrozoa and some of the problems related to it. The available data derived from descriptive and experimental studies are confined to only a few genera (Hydra, Tubularia, Cordylophora, Corymorpha, Campanularia, Pennaria). Without enumerating all possible types of regeneration, a number of the most significant cases are examined from various points of view. 2. Some of the anatomical and physiological particularities exhibited by the Hydrozoa have been emphasized as a possible basis for their remarkable morpho‐genetic abilities. The diploblastic architecture of a hydroid polyp is of a relatively simple design, lacking–in contrast to the higher Metazoa–a number of structurally and functionally well‐circumscribed organs. AH vital functions are distributed amongst a very small number of cell types, which have during their differentiation retained a relatively high standard of physiological autonomy and adaptability, being able to undergo, within certain limits, structural and functional transformation. Such differentiated somatic cells are subjected to normal senescence, which is compensated by a continuous (Hydra) or periodical (Tubularia) replacement activity. This rejuvenation process depends upon the presence of a permanent self‐proliferating stock of indifferent replacement cells (interstitial cells). 3. In a single polyp or in a colony the quantitative pattern of the morphogenetic or regenerative potentials is inversely proportional not only to the degree of tissue differentiation (Needham, 1952), but also to the progress of physiological ageing. In this particular case the age of a tissue or body fraction is not determined so much by the age of the somatic elements as by the number of available undifferentiated replacement‐cells. In the hydrocaulus of Tubularia the graded morphogenetic potentials are proportional to the degree of basipetal ageing of the coenosarc tissue. 4. The organogenetic pattern of a developing regenerate is constituted by differentiated somatic cells, which migrate to or are shifted towards the site of recon‐stitution together with the undifferentiated interstitial cells. The function of organizer is delegated to the endoderm layer, while the interstitial cells provide the regenerate with additional young elements which differentiate according to their position in the pre‐established organogenetic pattern. The quantitative behaviour of nucleic acids, free amino acids and proteolytic enzymes suggests that the structural differentiation of the regenerate is accompanied by a synthesis of new, probably organ‐specific proteins. 5. The mechanism by which the regenerating system controls the morphogenetic activities includes an inhibitory principle. In fact the hydranths of various species were found to produce a factor which has the faculty of reversibly inhibiting the recon‐stitution of an equivalent structure in the same morphogenetically active system. Within a developing regenerate the rate of production of...

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Section: (B) the Interstitial Cellsmentioning

confidence: 99%

Section: (C) the Histodynamics Of Regenerationmentioning

confidence: 99%

Regeneration in the Hydrozoa

Tardent

1963

Biological Reviews

110

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“…Not all limb surgeries performed in the laboratory are simple amputation surgeries. For over a hundred years regenerative biologists have performed complex surgical manipulations to reveal the logic of tissue patterning during regeneration (Brunst ; Carlson ; French et al. ; Stocum ; Maden ; Bryant et al.…”

Section: Introductionmentioning

confidence: 99%

Probability of regenerating a normal limb after bite injury in the Mexican axolotl (Ambystoma mexicanum)

Thompson

Muzinic

et al. 2014

Regeneration

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Multiple factors are thought to cause limb abnormalities in amphibian populations by altering processes of limb development and regeneration. We examined adult and juvenile axolotls (Ambystoma mexicanum) in the Ambystoma Genetic Stock Center (AGSC) for limb and digit abnormalities to investigate the probability of normal regeneration after bite injury. We observed that 80% of larval salamanders show evidence of bite injury at the time of transition from group housing to solitary housing. Among 717 adult axolotls that were surveyed, which included solitary-housed males and group-housed females, approximately half presented abnormalities, including examples of extra or missing digits and limbs, fused digits, and digits growing from atypical anatomical positions. Bite injury likely explains these limb defects, and not abnormal development, because limbs with normal anatomy regenerated after performing rostral amputations. We infer that only 43% of AGSC larvae will present four anatomically normal looking adult limbs after incurring a bite injury. Our results show regeneration of normal limb anatomy to be less than perfect after bite injury.

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Denervation‐induced changes in soluble protein content during forelimb regeneration in the adult newt, Notophthalmus viridescens

Dearlove

Stocum

1974

J. Exp. Zool.

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Denervation-induced alterations in the composition of the soluble protein population of various stages of forelimb regenerates in the adult newt were examined. Denervation alters the normal protein arrays in three ways: (1) proteins may be eliminated from an array, (2) proteins not normally present in an array may be induced to appear, and (3) proteins unique to d e nervated regenerates may appear in an array. The character of the denervationinduced alteration at five days post-amputation is basically different from that at later stages of regeneration. The stages during which the regenerate is b e coming independent of the nerve for its morphogenetic activity are the ones in which the protein profiles are the most drastically altered. Morphogenetic independence of the nerve therefore does not require the synthesis of nerve dependent proteins, and it is concluded that nerve independence is a property generated by the production of a critical number of blastema cells. Nerve dependent proteins are required for the mitotic activity which leads to attainment of the critical mass, and the failure of denervated early regenerates to continue regeneration may be due solely to mitotic inhibition.

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Some Problems of Regeneration

Cited by 9 publications

References 0 publications

Regeneration in the Hydrozoa

Regeneration in the Hydrozoa

Probability of regenerating a normal limb after bite injury in the Mexican axolotl (Ambystoma mexicanum)

Denervation‐induced changes in soluble protein content during forelimb regeneration in the adult newt, Notophthalmus viridescens

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