摘要:

AbstractStudies were conducted in order to determine the nature of the action of x‐irradiation on regeneration of the urodele forelimb. Right and left forelimbs of adult newts were parabiosed along their posterior edges, after the right limbs had been irradiated with 2,000 r. Forelimbs of control animals underwent similar operations. However, both limbs remained unirradiated. The angles which the stumps made with each other were classified as parallel, acute, and wide angles. Sixty days after amputation of these limbs, the cartilage patterns of the two groups were compared. In the control series, as the angle between the stumps was increased, the number of digits in the bilaterally symmetrical regenerates decreased, with a loss of central structures. At very wide angles, the doubled stumps produced no regenerates. In the experimental series, there were no interference effects from the irradiated right forlimbs. Single normal asymmetric left hands regenerated, despite widening angles between the stumps. Sham operations, which were performed on irradiated and unirradiated limbs, seemed to have no effect on the regenerative capacities of the limbs, with no regeneration in 97.7% of the irradiated limbs and normal regeneration in 91.1% of the unirradiated limbs. X‐rays seem to act on the limb to eliminate the interference effects normally found in regenerating doubled stumps. This seems to involve a disruption of the longitudinal control of the regeneration field. The loss of inter‐tissue communication and possible loss of the bioelectric field is disc

ISSN:0022-104X    

DOI:10.1002/jez.1401680402

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

年代:1968

数据来源: WILEY

摘要:

AbstractThe chameleon ear presents special problems because of variations of structure from the usual lizard pattern: there is no external ear opening and no visible tympanic membrane, and the round window of the cochlea is usually said to be lacking.Measurements of auditory sensitivity in terms of the electrical potentials of the cochlea were carried out in two species,Chamaeleo senegalensisandChamaeleo quilensis. The results indicated poor sensitivity in comparison with lizards in general, yet the performance was not far below that found in many species with conventional sound‐conducting systems. The frequency range extended from 100 to 10,000 cps, with the best sensitivity in the region of 200 to 600 cps.Experiments were carried out to investigate the operation of these ears in response to aerial sounds and mechanical vibrations. The observations indicated that aerial sounds are received by a special surface, the pterygoid plate, embedded in the tissues at the side of the head. This system resembles that of snakes, in which a detached quadrate bone serves as a receptive surface.The round window problem is not yet solved, but the suggestion is made that there is a path of pressure discharge from the scala tympani to the air of the middle ear cavity by a circuitous route, through the tympanic recess and a series of small spaces and blood vessels traversing the glossopharyngeal foramen. The frictional resistance of such a hindered pathway of discharge could account for the poor sensitivity of these chameleon ear

ISSN:0022-104X    

DOI:10.1002/jez.1401680403

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

年代:1968

数据来源: WILEY

摘要:

AbstractVarious types of testicular abnormalities, encountered indeep orange (dor) Drosophila melanogastermales, have been described. These abnormalities range from complete failure of attachment and, therefore, of elongation and coiling of both testes, to attachment and partial elongation of one testis.The frequency of testicular dysgenesis among affected lines can be readily modified by varying the culture conditions or the genetic background.The occurrence of a relatively high incidence of abnormalities among males bearing an X‐chromosome balancer (FM4) is reporte

ISSN:0022-104X    

DOI:10.1002/jez.1401680404

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

年代:1968

数据来源: WILEY

摘要:

AbstractThe sensitivity of the chronically denervated salt gland of the domestic goose to hypertonic, oral salt loading was investigated. In conscious geese the chronically denervated salt gland was supersensitive to an oral salt load. d‐Aldosterone did not appear to stimulate either the normal or denervated glands above control experiments. However, aldosterone did have a tendency to cause prolongation of secretion tim

ISSN:0022-104X    

DOI:10.1002/jez.1401680405

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

年代:1968

数据来源: WILEY

摘要:

AbstractThe relation of embryonic age and state of differentiation of cells to their capacity to reconstruct integumental tissues was studied in aggregates of cells dissociated from the skin of 13‐ to 15‐day mouse and 8‐day chick embryos. To attain advanced morphogenesis of the reaggregates, cell suspensions were placed and aggregated on the chorioallantois of chick embryos; the following cell combinations were studied: (1) chick skin cells (epidermal and dermal; (CS), (2) mouse skin cells (epidermal and dermal; MS), (3) MS commingled with CS, (4) mouse epidermal cells (Me) commingled with CS, (5) mouse dermal cells (Md) commingled with CS. Reaggregated MS from 13‐ to 15‐day embryos reconstructed typical mouse skin structures: hair and stratified, keratinized epidermis. Similarly, reaggregated CS reconstructed typical feathers and thin nonkeratinized skin. In bispecific CS + MS aggregates, MS from older embryos (14–15 days) completely suppressed feather development, but formed hair and sheets of bispecific chimeric keratinized epidermis. In contrast, MS from 13‐day embryos co‐aggregated with CS did not suppress feather morphogenesis; in such bispecific aggregates both hair and feathers developed, as well as chimeric epidermis. Most striking was the frequent formation in this combination of “chimeric feathers” in which mouse cells were included in feather structures. Mecontributed to the epidermal elements of the feather; Mdformed groups at the site of the feather dermal papillae. This changeover in mouse cells from participation in feather morphogenesis in aggregates to its suppression is closely correlated with their developmental age. The contributions of these results to the understanding of histotypic specificity and morphogenetic cell interac

ISSN:0022-104X    

DOI:10.1002/jez.1401680406

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

年代:1968

数据来源: WILEY

摘要:

AbstractUtilizing starch gel electrophoresis, a study was made on the albuminlike plasma protein of a tetraploid South American species of frog. No allelic polymorphism at this locus was indicated in the congeneric diploid speciesO. cultripes, but five distinct electrophoretic phenotypes were encountered among 141 frogs of the tetraploid speciesO. americanus. These included two homozygous types each with a single distinctive albumin‐like band, and three heterozygous types. The three heterozygotes differed from each other by relative staining intensity of the bands, and presumably represent 3:1, 2:2, and 1:3 ratios of allelic dosage. The frequency distribution of the five phenotypes among 141 frogs fitted well with the expected values calculated on the basis of the binomial (p + q)4with allelic frequencies of 0.415 and 0.58

ISSN:0022-104X    

DOI:10.1002/jez.1401680407

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

年代:1968

数据来源: WILEY

摘要:

AbstractThein vitroresponse of renal microbodies and lysosomes to a variety of altered physical and chemical conditions was examined. The influence of these conditions upon the integrity of the organelles was determined as that proportion of the total activity of various “marker” enzymes (α‐hydroxy acid oxidase, catalase and D‐amino acid oxidase for microbodies, and acid phosphatase for lysosomes) which was released from the organelles and recovered in the soluble phase following treatment.Microbodies and lysosomes were separated by differential centrifugation from 15% homogenates of male, rat kidney prepared in 0.25 M sucrose. After exposure to experimental treatments, the preparation was further separated into sediment and supernatant fractions by centrifugation at 100,000 × g for 30 minutes. The sediment and supernatant fractions were assayed to determine the distribution of the “marker” enzymes.Eighty to 100% of the activities of α‐hydroxy acid oxidase and catalase were found in the supernatant after exposure of the microbody‐lysosome fraction to low concentrations of Triton‐X 100 or digitonin, or after treatment by sonic vibrations or high speed laminar shearing. Lesser but significant proportions of the total activities of these enzymes were recovered in the soluble phase after exposure of the organelles to distilled water, 0.1 M Sorensen's phosphate buffer or 0.1 M TRIS‐HCl buffer prepared in distilled water. Acid phosphatase showed lower levels of release into the supernatant under most of these conditions.When microbody‐lysosome preparations were exposed to sucrose in concentrations of 0.1 M to 0.8 M to phosphate buffer in 0.25 M sucrose or to TRIS‐HCl buffer prepared in 0.25 M sucrose, the release of α‐hydroxy acid oxidase, catalase and acid phosphatase was insignificant. However, under these conditions D‐amino acid oxidase was released into the soluble phase to a significant extent.These results suggest that α‐hydroxy acid oxidase and catalase are soluble constituents of renal microbodies while D‐amino acid oxidase is associated firmly with a sedimentable component of the organelle, and that renal microbodies a

ISSN:0022-104X    

DOI:10.1002/jez.1401680408

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

年代:1968

数据来源: WILEY

摘要:

AbstractThe specific activities of succinic dehydrogenase (SD) and cytochrome oxidase (COX) were determined for mitochondria of chick liver, heart, and skeletal muscle from the seventh day of incubation through the time of hatching. The levels of activity of both enzymes at hatching and the rate and course of the developmental changes by which the final levels are reached are different and specific for mitochondria of the three tissues studied. During development changes in activity of both enzymes occur in parallel so that the ratio of SD/COX remains constant. Furthermore, the ratio is the same for the three types of mitochondria. Cytochrome oxidase is completely localized in the insoluble protein fraction (membrane fraction) of all mitochondria examined, and the change in COX during development varies temporally and quantitatively with the proportion of insoluble protein. When calculated on the basis of insoluble protein, specific activities of SD and COX are constant throughout development; furthermore, differences in activity among the mitochondria of the three tissues disappear. It is concluded that mitochondrial differentiation reflects the appearance of specific proportions of membranes and matrix.

ISSN:0022-104X    

DOI:10.1002/jez.1401680409

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

年代:1968

数据来源: WILEY

摘要:

AbstractPronuclear mouse eggs were maintained in globulin‐citrate‐Locke's solution for 120 to 180 minutes at one of the following temperatures: 22–23°C (room), 35–36°C (incubator) or 2–3°C (refrigerator). Their viability was then compared with that of untouched eggs and with eggs immediately transferred from donor to host. After maintenance at room temperature the vitelline membrane shrank irregularly within the zona pellucida; on the other hand, in the pronuclear eggs maintained at refrigeration temperature this did not occur. In contrast, the cytoplasm of the incubated eggs was highly condensed and the vitellus shrunken, although the vitelline surface remained smooth. Survival rate of eggs, as tested by transplantation, was lower after incubation than after refrigeration. Body weight of fetuses developed from eggs maintained at room temperature and refrigeration temperature was significantly less than that of fetuses developed from untouched control eggs, from eggs immediately transferred to a host animal, or from eggs maintained at incubation

ISSN:0022-104X    

DOI:10.1002/jez.1401680410

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

年代:1968

数据来源: WILEY

摘要:

AbstractThe possibility of obtaining fertilization of mammalian eggs at sites in the reproductive tract other than the ampulla of the Fallopian tube appears to have received little attention. Following transplantation of recently‐ovulated hamster eggs from the tubes of 66 donors into the uterine horns of a similar number of mated or inseminated recipients at known stages of the estrous cycle, none of 392 recovered eggs was found to be fertilized after periods of between two and eight hours in the uterus. All eggs were completely denuded of cells of the cumulus oophorus and corona radiata at recovery, but spermatozoa were not found attached to or within the zona pellucida. Large globules, presumably derived from deutoplasmic components of the vitellus, were observed in the perivitelline space of transferred eggs recovered from the uterus on the morning after ovulation; the vitelline membrane appeared to be damaged in a proportion of these eggs. However, apart from such adverse effects of the uterine fluids upon the egg membranes, it should also be considered that hamster spermatozoa may require exposure to the environment of the Fallopian tube before they acquire the ability to penetrate the egg

ISSN:0022-104X    

DOI:10.1002/jez.1401680411

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

年代:1968

数据来源: WILEY