摘要:

AbstractGraded dosages of x‐irradiation from 500r to 3000r inhibited destruction ofDiemictylus viridescensallografts at 23 ± 0.5°C for at least as long as the survival time of the hosts (up to 35 days). Lymphocytes were observed in 20% of the grafts whose hosts received 500r and 1000r but they were present in far weaker concentrations than seen in any control grafts at all stages of rejection. No lymphocytes were evident in any grafts on hosts irradiated with 1500r, 2000r, and 3000r.The effects of various temperatures on allograft rejection in the newt were also examined. There was no difference in the mean survival times of grafts maintained at 30°C and 23°C. At 20°C, however, hemostasis and hemorrhaging were significantly delayed by a factor of 1.6 and 1.7 times, respectively, when compared with the findings at 23°C. At 10–15°C, no hemostasis or hemorrhaging were displayed for 191 days after transplantation. Lymphocytes, however, were apparent in very low concentrations in the tissues of some of the grafts and localized destruction of a few melanophores were noted. Two grafts maintained at 10–15°C for 155 days and then transferred to 20°C were completely destroyed within 36 days. This destruction was more rapid than for grafts initially main

ISSN:0022-104X    

DOI:10.1002/jez.1401630302

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

年代:1966

数据来源: WILEY

摘要:

AbstractGradual osmotic hemolysis of camel erythrocytes was observed by means of phase contrast microscopy and recorded by microcinematographic methods. It was found that the normal ovoid erythrocytes become spherical when the solution surrounding the erythrocytes is diluted ionically, and they swell to 240% of the initial volume. After hemolysis the erythrocyte membranes (ghosts) revert to their original oval form.Comparative studies of osmotic fragility tests on red blood cells of growing and adult camels showed the presence of two distinct cell populations in growing camels. One corresponds to the adult blood. The second cell type is more resistant to osmotic pressure and is found only in the young camel.

ISSN:0022-104X    

DOI:10.1002/jez.1401630303

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

年代:1966

数据来源: WILEY

摘要:

AbstractThis report is concerned with the origin and elaboration of melanin in the retinal epithelium ofAmblystoma punctatum.The animals used in this study developed from a single clutch of unpigmented eggs. The tapetum of such animals is devoid of ovarian pigment and, consequently, the initial formation of melanin can be readily followed. Specifically examined is the possibility of active involvement of melanocytes in the formation of tapetal pigment.Eyes were transplanted from embryos at stage 32+ into the gill region and ventral flank of embryos at stage 28. Data were obtained concerning the initial appearance of melanin and its subsequent elaboration in the tapetum of the grafts correlated with the presence or absence of melanocytes in the immediate vicinity.Melanin first appears in the flank grafts two to three days before melanocytes reach the area. Sequence of melanin elaboration in both types of graft follows more closely that of the donor animals than that of the less advanced hosts. Melanin always appears first in the anterior portion of both grafts and intact eyes, despite the fact that melanocytes are just as closely associated with the posterior pole of the eyes. It is concluded that melanin production is an intrinsic property of the retinal epithelium inAmblystoma.

ISSN:0022-104X    

DOI:10.1002/jez.1401630304

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

年代:1966

数据来源: WILEY

摘要:

AbstractLactate dehydrogenase (LDH) isozymes of two genera within the family Salmonidae (SalvelinusandSalmo) were examined by acrylamide and starch gel electrophoresis. Those species examined contain three isozyme series involving five different kinds of subunits. TheA‐Bseries, believed to be homologous to LDH 1–5 in the majority of vertebrates, is found in nearly all tissues. Polymorphism for subunitBwas discovered inSalvelinus fontinalisin which two kinds,BandB', are present within a number of inbred strains. Various crosses and backcrosses involvingS. fontinalisandSalvelinus namaycushdemonstrate that subunitsAandBare each coded by different autosomal genes (LA and LB). A limited amount of test‐cross data indicates linkage of these genes. Partial genetic analysis indicates that a second series of several LDH isozymes, largely restricted to the retina, involves a third subunit, C, in combination withBand to a lesser extent withA.A variant form of subunit C was found inSalmo trutta.Comparison of patterns ofS. fontinalisandS. truttaand their hybrid seems to indicate that two additional subunits are involved in a third series of five isozymes found in the skeletal muscle of each species exa

ISSN:0022-104X    

DOI:10.1002/jez.1401630305

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

年代:1966

数据来源: WILEY

摘要:

AbstractThe three dimensional structure of the filiform papilla of the mouse tongue is presented.Two distinctly different keratinized cell products are found in the region of the filiform papilla. Evidence for the existence of the two cell types is based on a series of histological, cytological, micro‐manipulative and cell migration studies.A study of the tongues of embryonic and adult mice shows no morphological evidence of heterogeneity in the cells of the basal layer of epithelium which supports the concept that the two different keratinized cell products derive from a homogeneous cell population.Tritiated thymidine autoradiographic studies reveal that the proliferative pool of epithelial cells is limited to the basal cell layer. The avergae cell renewal rate of this layer is presented for the various parts of the tongue. The progenitor cell cycle is also described.The studies indicate that the movement of a cell from the basal layer to the spinous layer is a random event in time and that the movement of a cell out of the basal layer precludes further cell proliferation by that cell.The results indicate that it is positional chance at the time of cell birth which determines whether a cell will specialize into one of two different alternate fates. The fate of the cell in this particular case is based on the particular micro‐environment the cell is forced to occupy. The force is provided by the growth of cellular mass and the subsequent crowding out of those cells not able to remain attached to the basement membr

ISSN:0022-104X    

DOI:10.1002/jez.1401630306

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

年代:1966

数据来源: WILEY

摘要:

AbstractA quantitative radioautographic study of RNA synthesis in the diverse cell types of theXenopusblastula and gastrula is described. Nuclear activation, studied as increase in the number of grains in nuclear RNA after pulse‐labelling with uridine H3, was found to occur abruptly just before gastrular movements become observable. Presumptive endoderm and mesoderm participate in this widespread activation, while presumptive ectoderm becomes activated shortly after, at mid‐gastrulation. It is shown that per‐nucleus rates of high molecular weight, non‐ribosomal RNA synthesis increase at least 20 fold within one hour in endoderm and mesoderm as the embryo prepares to enter gastr

ISSN:0022-104X    

DOI:10.1002/jez.1401630307

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

年代:1966

数据来源: WILEY

摘要:

AbstractCiliates dividing and not dividing were fused by cell grafting to characterize, by the interactions, cell states during division and interdivision. Control grafts of divider × divider showed that the operation itself was unimportant for the results (contrary to Weisz, '56). In the majority of cases the trophic component of a graft induced primordium resorption and regression of division in the divider. Thus it appears that trophic stentors actively inhibit their own division with a blockage that can extend to a conjoined divider. That disinhibition is the onset of division and persists only until division is assured was indcated by the findng that both late dividers and predividers can induce division regression. Only in grafts precisely balanced with respect to relative sizes of the partners and division stage of the divider did dividers induce direct division of fusion partners that would not otherwise have divided. In fork‐tailed stentors both cell bodies divide although a division primordium appears in only o

ISSN:0022-104X    

DOI:10.1002/jez.1401630308

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

年代:1966

数据来源: WILEY

摘要:

AbstractAnin vivoexperimental design is described for the study of capacitation that permits simultaneous testing of both sperm capacitation and viability in two series of recipient does. In this system, superimposed capacitation is prevented in one of the series by performing tubal insemination 13 hours after HCG injection.Using this system it is possible to demonstrate that: the timing of tubal insemination is critical for the study of capacitation; there is no difference in terms of time required for capacitation between spermatozoa from the distal cauda epididymidis and from the ejaculate;in vitrocapacitation does not result from sperm incubation with endometrium strips; ten hours incubation of sperm suspensionin vivoin a double ligated and distended uterine horn delays capacitation without altering sperm fertilizing ability.

ISSN:0022-104X    

DOI:10.1002/jez.1401630309

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

年代:1966

数据来源: WILEY

摘要:

AbstractWhen spermatozoa from specific segments of the epididymis were inseminated intra‐tubally, ten hours before ovulation, virtually no ova were fertilized by sperm samples taken from the regions proximal to the middle of the corpus epididymidis. Sperm from the caput epididymidis and the proximal half of the corpus region not only fail to fertilize, but are also apparently unable to establish contact with the surface of the zona pellucida. Although a maximal fertilization rate was obtained with sperm samples from the lower part of the corpus epididymidis, significantly greater numbers of supplementary and zona surface spermatozoa were found in association with tubal ova exposed to similar numbers of sperm from the cauda epididymidis. This latter finding suggests that the cauda region contains a relatively higher percentage of mature spermatozoa, and thus that a proportion of spermatozoa do not become functionally mature until they have passed from the corpus epididymidis.Approximately 7% and 5% of ova exposed to spermatozoa from the lower corpus and cauda regions, respectively, contained three and occasionally four pronuclei, quite probably as a consequence of polyspermic fertilization. As no polyploid ova were found after similar exposure to greater numbers of ejaculated spermatozoa (Adams and Chang, '62), it is conceivable that there may be other systems on the sperm head, as well as those concerned with penetration of the zona, which also mature in some way during epididymal passag

ISSN:0022-104X    

DOI:10.1002/jez.1401630310

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

年代:1966

数据来源: WILEY

摘要:

AbstractTrunk neural folds from both black and white axolotls,Ambystoma mexicanum, were transplanted unilaterally in place of folds ofTaricha torosaneurulae. Melanophores from either kind of axolotl completely suppress the differentiation ofT. torosamelanophores for several stages and largely suppress it for much longer. During larval stages host pigmentation gradually develops, but axolotl pigmentation always dominates. After metamorphosis the typicalAmbystomaspotted pattern appears. During all stages donor melanophores are almost equally distributed on both flanks, with only slightly more on the grafted side. Guanophores predominate on the grafted side, while xanthophores predominate on the opposite side. With the exception of the distribution of axolotl melanophores, these results confirm results of others with the black axolotl and offer additional evidence that the chromatophores of both black and white axolotls are equivalent. New suggestions are made to explain the unequal distribution of xanthophores and guanophores in view of the nearly equal distribution of axolotl melanophores.Trunk neural folds ofT. torosawere transplanted bilaterally in place of white axolotl neural folds. The typicalT. torosalarval pigment pattern is expressed in the grafted area, but host melanophores suppress donor melanophores beyond the confines of the graft. Eventually all axolotls immunologically rejected their neural crest grafts. Only 13% of theT. torosarejected their grafts. These results confirm thatT. torosahas a much greater tolerance to grafted foreign tissue than do axolotls. The immunological behavior of these animals is discussed in the context of results of similar experiments in anurans.

ISSN:0022-104X    

DOI:10.1002/jez.1401630311

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

年代:1966

数据来源: WILEY