摘要:

AbstractIn the present study, lenses were removed from the eyes of adult anesthetized newts, macerated in 0.03Mborate buffer at pH 8.6, and separated by starch gel electrophoresis. Upon staining with amido black 10‐B, seven distinct staining areas appeared in the blocks. Three bands moved toward the anode, and three toward the cathode. In addition, a seventh moiety represented by a smear of material moved toward the anode. One millimeter times five tenths millimeter plugs were removed from each of these areas and were placed into freshly lentectomized eyes. Plugs from most strongly positive and most weakly negative proteins inhibited lens regeneration. In addition, plugs from the area containing the weakly negative protein induced either lenses with aberrant polarity or double centered lenses with centers of opposed polarity. All other protein bands had no significant effect on regeneration.In addition to the above experiments, homogenates and proteinase‐digested homogenates of lenses were injected into eyes following lentectomy. Three 5‐μl samples were injected in each case over a six day period. Injection of the plain homogenate stimulated lens regeneration markedly, while the proteinase destroyed the stimulatory activity.Theoretical considerations of the above data are dis

ISSN:0022-104X    

DOI:10.1002/jez.1401590202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1965

数据来源: WILEY

摘要:

AbstractThe isozymic forms of four dehydrogenases, separated by disc electrophoresis in acrylamide gels, have been studied during development and in adult organs in the cyprinodontiform fish,Oryzias latipes, the medaka. Xanthine dehydrogenase appears as a single molecular form at hatching, and in the adult fish is found only in the liver and gut. Glucose‐6‐phosphate dehydrogenase is a single enzyme in early development, just before hatching two new forms appear, and after hatching all three decrease in whole larval extracts. In adults, the enzymes were found only in brain, liver, and ovary. Malate dehydrogenase increases from a single molecular form in early stages to five or six after hatching. Each adult tissue has its characteristic assemblage of isozymes. The only lactate dehydrogenase detectable before hatching is isozyme 5, and four others appear abruptly at hatching. All adult organs have one to three LDH isozymes, but isozymes 1 and 2 were found only in the retina of the eye. The abrupt change from the single isozyme 5 to the full complement occurs also in eyes of the larvae taken pre‐ and post‐hatching. Homogenates of pre‐hatching embryos do not inhibit the electrophoretic separation or reactivity of isozymes 1, 2, 3, and 4 of post‐hatching larvae. Presumably hatching triggers the appearance of the more rapidly migrating isozymes, especially strongly in the retina. On the basis of the structure of LDH isozymes in other organisms, it can be concluded that polypeptide A is present before hatching, but some restraint on the synthesis or activation of polypeptide B seems to be removed by hatching. The importance of hatching as a time of qualitative change in these four enzymes is correlated with increases in other metabolic activities a

ISSN:0022-104X    

DOI:10.1002/jez.1401590203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1965

数据来源: WILEY

摘要:

AbstractThe fine structure of neurons from regenerating hydra was studied. The ganglion cells of regenerating hydra in contrast to those of normal hydra contain denser and sometimes multiple nucleoli, polyribosomes, and membrane‐bounded accumulations of dense homogeneous material which appears to be elaborated by the Golgi apparatus. During regeneration, membrane‐bounded dense granules disappear from the perikaryon of neurosecretory cells and accumulate in the processes. They are released by fusion of the vesicle membrane with the plasma membrane of the neurite. A large number of intermediate stages of differentiation of neurons from interstitial cells are present after 12 hours of regeneration. These observations support the hypothesis that neurosecretory substance released at nerve terminals plays a significant role in the regulation of growth and differentiation in the regenerating hy

ISSN:0022-104X    

DOI:10.1002/jez.1401590204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1965

数据来源: WILEY

摘要:

AbstractDimensions of the longest intestinal microvilli were measured in normal mice from the 14 day embryo through weaning. Major changes are associated with birth and weaning. Microvilli increase in height and volume before birth and after birth increase in height but keep the same volume by decreasing in diameter. There is thus an increase in surface area associated with birth and with weaning. This correlates with the increases in alkaline phosphatase activity of mouse intestine at these times as described by Moog. Location of reaction product suggests that phosphatase is associated with the inner layer of the unit membrane. Attempts to reproduce the normal shape changes of microvilli by injecting 9 to 10 day old mice with cortisone failed. The microvilli increased in height but did not decrease in diameter.

ISSN:0022-104X    

DOI:10.1002/jez.1401590205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1965

数据来源: WILEY

摘要:

AbstractThe photosensitive weaver bird (Ploceus philippinus) has a long juvenile phase when, while the bird is insensitive to photostimulation, the gonads respond to injected gonadotrophins. It is suggested that the immature status of the hypothalamo/hypophyseal complex may be responsible for the presence of a long pre‐photoresponsive phase in this bir

ISSN:0022-104X    

DOI:10.1002/jez.1401590206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1965

数据来源: WILEY

摘要:

AbstractThe prostatic complex ofDidelphis virginianaKerr has been studied by a variety of cytological and cytochemical means. Segment I was characterized by an apocrine type secretory mechanism. The apical parts of the epithelial cells, which were shed into the glandular lumen, contained vesicles which give positive cytochemical reactions for acid phosphatase, aliesterase, 5′‐nucleotidase, and nucleoside diphosphatase. These vesicles also contained material which was reactive with the periodic acid‐Schiff test for mucopolysaccharide and Baker's test for phospholipid. Segment II was characterized by the presence of two types of cells in the glandular epithelium. Type A cells contained large rounded secretory granules which gave positive reactions for acid mucopolysaccharides but not for proteins. Type B cells contained large elongate secretory granules which gave positive reactions for proteins but not for polysaccharides. Electronmicrographs indicated these secretory granules to have distinctive morphologies and to contain complex crystalloid material. No cells with characteristics intermediate between those of the A and B types were observed. Segment III of the prostatic complex was characterized by the presence of large amounts of glycogen both in the epithelial cells and within the glandular lumen. These observations indicate a remarkable degree of morphological and biochemical heterogeneity on the part of the prostatic complex of this a

ISSN:0022-104X    

DOI:10.1002/jez.1401590207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1965

数据来源: WILEY

摘要:

AbstractIt has been shown previously that the gonopodium ofLebistesdevelops and regenerates under the influence of testicular hormone. Since it has also been demonstrated that hypothyroidism inhibits gonopodial differentiation in the young fish, the relation between the hypothyroid state and gonopodial regeneration deserves investigation.Adult male guppies kept in 0.03% thiouracil fail to regenerate normal gonopodia and the longer the exposure, the greater the inhibition. However, thiouracil has no effect on the regeneration of the female and fin. Thiouracil treatment results in thyroid follicular hyperplasia and vacuolization of and fat deposit in the liver. However, it is postulated that inhibition of anal fin regeneration in the male following thiouracil treatment is not the result of disturbance in protein or fat metabolism, but is due to a hormonal imbalance.

ISSN:0022-104X    

DOI:10.1002/jez.1401590208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1965

数据来源: WILEY

摘要:

AbstractDevelopmental mechanisms inEuplotes plumipeswere analyzed in terms of theresponse to damage produced by a UV microbeam. Individual animals, representing all stages of the morphogenetic cycle, were irradiated at a variety of cortical sites, including bases of mature cirri and membranelles, primordial structures, and non‐ciliated regions; they were then observed and fixed for silver‐staining.Immediate damage is restricted to cortical and ciliary structures directly irradiated. Irradiated cirri and membranelles, including their associated basal structures (infraciliature), are effectively destroyed after about two minutes exposure to the UV microbeam. Contrary to what might be expected from the reports of earlier workers using microsurgical techniques, no regeneration response ensues following such damage in these animals. Damage to cirri perists until these organelles are replaced during normal pre‐division morphogenesis; damage to adoral membranelles, which are not normally replaced at division, persists indefinitely through succeeding generations of proters. It is concluded that destruction of infraciliary structures does not, in itself, provide a sufficient stimulus to regeneration inEuplotes.Irradiation of either mature or primordial cortical organelles can be effective, however, in causing the temporary arrest of normal pre‐division morphogenesis, including resorption of all primordial stuctures, and the arrest or disappearance of macronuclear replication bands. The probability that resorption will occur depends, in part, on the developmental stage of the structures irradiated: irradiation of primordial structures during early stages induces this response more frequently than does irradiation of late stage primordia or mature organelles. These results are discussed in terms of the functional relationship between infraciliary structures and the mechanisms controlling deve

ISSN:0022-104X    

DOI:10.1002/jez.1401590209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1965

数据来源: WILEY

摘要:

AbstractInductive tissue interaction involved in lens differentiation in the mouse embryo has been studied using millipore filter culture methods. The entire eye rudiment (nine day embryo) comprising optic vesicle, surrounding mesenchyme and overlying ectoderm differentiatedin vitrointo lens and retina, essentially as in normal development. Individual tissue components of trypsin‐separated lens primordia lost their structural organization when cultured alone, but lens epithelium in combination with mesenchyme was maintained as a vesicle without obvious lens fiber formation. Tissue recombination experiments show that differentiation of lens fibers in the presumptive lens ectoderm as well as in the lens placode depends on the inductive influence of optic cup. This influence can pass through a millipore filter barrier of 25 μ thickness and 0.45 μ porosity. Differentiation of lens fibers in the anterior lens epithelium of later embryos was also dependent on the inductive action of neural retina, suggesting the presence of continued inductive interaction in lens formation. The initial influence of optic vesicle on the presumptive lens ectoderm seems to be critical and of short duration, leading to the formation of a placode which has acquired stabilized lens forming property. Continued realization of this property depends on further inductive act

ISSN:0022-104X    

DOI:10.1002/jez.1401590210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1965

数据来源: WILEY

ISSN:0022-104X    

DOI:10.1002/jez.1401590201

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1965

数据来源: WILEY