摘要:

AbstractSpecimens of the newt,Triturus cristatus carnifex(Laurenti), rendered totally anemic, restore erythron by cyclic waves of erythropoietic activity that alternate with intervals of stasis. Hemolysis is obtained by administering 25 mg/liter of acetylphenylhydrazine in the breeding water for 36 h. The first cycle of erythropoietic activity produces microcytes, which have completely differentiated by 8 weeks after treatment. However, if the animals are raised in a hyperbaric chamber at a pressure of 1.5 atmospheres, in order to compensate for hypoxia, normocytes are produced. In both cases the hematocrit and hematic concentration of hemoglobin reach analogous values, so microcythemia appears to be the only effect of hypoxia. The hemoglobin, hematocrit values, and normocyte counts in hyperbaric animals are about onehalf those of the controls newts. These data, together with those on the life span of red blood cells (RBC) and time span between two successive erythropoietic cycles (2 months and 1 month, respectively), indicate that the newts normally keep only two sets (one new, one old) of RBC in circulation, whose approximate parameters can be defined as RBC count: 60,000/mm3, hematocrit: 17%, and hemoglobin: 5.4 g/100 ml.

ISSN:0022-104X    

DOI:10.1002/jez.1402440202

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

年代:1987

数据来源: WILEY

摘要:

AbstractThe central projection patterns of afferents from normal and duplicated legs and antennal aristae inD. melanogasterwere established by horseradish peroxidase or cobalt labelling. Duplications were obtained genetically, by usingl(1)ts726andengrailedmutants, which are known to produce supernumerary legs and aristae, respectively. In normal legs, afferents from singly innervated mechanoreceptive (M‐) bristles terminate in the lateral and medial periphery of the corresponding leg neuromere. The medial periphery is also occupied by terminals of multiply innervated chemoreceptive (C‐) bristles; another target of C‐bristles is the anterior margin of the neuromere. The sensory projection patterns of homologous M‐bristles on different leg segments are overlapping, suggesting that terminals are not ordered according to the proximo‐distal location of their cell bodies on the leg. The sensory projections of duplicated legs or aristae overlap the corresponding normal projections. However, when stimulating supernumerary legs in the proboscis extension paradigm, the frequency and intensity of reflex activity are significantly reduced compared to normal legs. These data suggest that normal and supernumerary afferents compete with one another in a subtle way which is not accompanied by gross morphological changes of the projection

ISSN:0022-104X    

DOI:10.1002/jez.1402440203

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

年代:1987

数据来源: WILEY

摘要:

AbstractWe have compared the anatomy of immature axolotl integument from limb‐forming regions with adjacent non‐limb‐forming regions of the flank, concentrating on the earliest stages of limb bud development. We have extended these observations to include prominent buds just prior to their differentiation. At the ultrastructural level, we note striking differences between these two regions of skin, including a complete loss of hemidesmosomes and tonofilaments in the basal cells of the epidermis; a marked deterioration of the basal lamella; and focal areas of desquamating cells in the apical regions of the bud—all characteristics of limb‐forming regions. These observations were made in the same larvae which provided measurements of a steady endogenous electric (ionic) current that either was coincident with or predicted the area of limb bud outgrowth (Borgens et al.:J. Exp. Zool.228:491–503, 1983). We discuss these physiological measurements, the changes in the anatomy of the bud‐forming region, and the relevance of these observations to our theory of early l

ISSN:0022-104X    

DOI:10.1002/jez.1402440204

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

年代:1987

数据来源: WILEY

摘要:

AbstractIn some species of sea urchin, such asLytechinus variegatusβ‐1, 3‐glucanase activity is present at two distinct developmental stages (in the unfertilized egg and again following gastrulation). There is a different form of the enzyme β‐1, 3‐glucanase specific to each stage, and these forms can be distinguished immunologically and biochemically. The distinguishing characteristics of the egg and embryonic enzymes were used to analyze the forms of β‐1, 3‐glucanase present in other species that express activity at only one of the two stages. The enzyme present inTripneustes esculentes, which has activity only early in development, is an 80,000 dalton enzyme antigenically similar to the egg enzyme inLytechinus.The enzyme present following gastrulation inEchinometra lucunter, however, is distinct from the egg enzyme and is similar to the embryonic enzyme inLytechinus, despite the absence of activity in the eggs ofEchinometra.These results indicate the two forms of β‐1, 3‐glucanase (egg and embryonic) are expressed independently and in a stage‐specific manner, suggesting they are not functionally equivalent. β‐1, 3‐glucanase ase activity was also analyzed in interspecific hybrids.Tripneustes esculentes(which normally lacks the embryonic form) suppressed the expression of the embryonic enzyme in crosses withLytechinus variegatus(which normally does express it). This suppression occurred whether theTripneustesgenetic material was maternal or paternal in origin. However, the embryonic enzyme normally expressed byEchinometrawas expressed in crosses of this species withTripneustes, i.e,Tripneustesdid not suppress enzyme expression in these hybrids. This differential effect on the expression of the embryonic stage enzyme in these hybrids suggests that the mechanisms leading to the expression of this enzyme differ inLytechinusandEchinometra, despite the biochemical

ISSN:0022-104X    

DOI:10.1002/jez.1402440205

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

年代:1987

数据来源: WILEY

摘要:

AbstractGuppy (Lebistes reticulatus) embryos pass through a distinct sequence of motor behaviors that leads to swimming capability during the course of their development. We have characterized these activities in order of appearance, with several corresponding morphological features, as belonging to the coil stage, tail‐twitch stage, S‐movement stage, and swimming stage. A primary feature of development was an increase in the amount of activity per unit of time over these four stages. The developmental pattern of motility was not interrupted by spinal transection until the onset of swimming, implying that supraspinal information is not required for the occurrence of the primitive behaviors that precede swimming. Elimination of swimming by spinal transection did not elicit a reversion to less complex activities, suggesting that once the cerebral control for swimming is developed, it represents a hardwired system not behaviorally reducible to antecedent compone

ISSN:0022-104X    

DOI:10.1002/jez.1402440206

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

年代:1987

数据来源: WILEY

摘要:

AbstractGrafts from pigmented donor embryonic eye rudiments into albino hosts were used to chart i) fates of local cell groups in three positions in whole eye rudiments, and ii) alterations in graft‐derived territories when the posterior half of the rudiment was ablated. Small pigmented patches of graft‐derived tissue were conspicuous in albino embryos and tadpoles, enabling us to directly monitor their location and size in the eyes of living animals. The three (right eye) positions marked by pigmented grafts were dorsal (12 o'clock), anterior (3 o'clock), and anteroventral (5 o'clock). Control transplants reared without secondary ablation produced blacksectorterritories in pigment retinal epithelium and iris at corresponding 12 o'clock or 2 o'clock or 4 o'clock positions on the larval eyeball. In the experimental series posterior half‐anlagen were ablated. The remaining anterior half‐anlagen, each containing a pigmented graft, reconstituted spherical larval eyeballs of reduced size. During healing, donor‐derived pigmented sector territories remained coherent, but were altered in position and size compared to controls. Dorsal cells (from 12 o'clock grafts) appeared to move rapidly along the newly formed cut edge into the wound and went on to form expanded black sectors in posterior eye regions. More gradually, sector territories of anterior cells (3 o'clock grafts) and anteroventral cells (5 o'clock grafts) shifted toward dorsal in a counterclockwise direction. Thus all three types of graft derived pigment territories were altered in eye anlage fragments as they healed to form half‐size sph

ISSN:0022-104X    

DOI:10.1002/jez.1402440207

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

年代:1987

数据来源: WILEY

摘要:

AbstractA simple and rapid method for mechanically isolating cells from fixed embryos ofOryzias latipeswas developed, in order to study the mitotic and pseudopodial activities of the cells during early development. Most of the sister cells retain cytoplasmic connections with each other until the prophase of the next mitosis, during the synchronous cleavage stage. The cells of the enveloping layer (EVL), an embryonic epithelium, never extrude pseudopodia. The appearance and the increase and decrease of six types of pseudopodial activity in deep cells during the blastula and gastrula stages are described, and an antagonism between the mitotic and the pseudopodial activities in deep cells has been documented in a quantitative manner. A noteworthy finding in the present study is the occurrence of an elongated intercellular cytoplasmic bridge, which connects members of pairs of postmitotic deep cells from the midblastula stage until the late gastrula stage. The intercellular bridge has been found for the first time in theOryziasembryo as a result of the newly developed method for the isolation of cells.

ISSN:0022-104X    

DOI:10.1002/jez.1402440208

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

年代:1987

数据来源: WILEY

摘要:

AbstractHemolymph and egg yolk proteins in the camel cricket,Ceuthophilussp., were analyzed by native and SDS‐polyacrylamide gel electrophoresis. Four sex‐specific polypeptides (FSYPs I–IV) accounted for 44% of the hemolymph protein in adult females. These polypeptides were absent from the blood of adult males and female nymphs but composed 63% of the yolk protein in fully grown oocytes. Hemolymph FSYPs became labeled with [35S]‐methionine after a 1‐hour period of in vivo incorporation and appeared in terminal, vitellogenic follicles after 2 hours of incorporation. Two‐dimensional gel electrophoresis showed that all four FSYPs occur in a single egg‐yolk glycoprotein also present in adult female hemolymph. We conclude that this glycoprotein is a multisubunit vitellogenin (VG). Two high molecular weight polypeptides synthesized by the fat body of adult females and immunoreactive with VG‐specific antiserum were tentatively ident

ISSN:0022-104X    

DOI:10.1002/jez.1402440209

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

年代:1987

数据来源: WILEY

摘要:

AbstractThyroid function was studied in Japanese quail,Coturnix japonica, and Ring doves,Streptopelia risoria, when both were fed the same dietary iodine (I; 930 μg I/kg). We also compared thyroid function in groups of doves receiving low I (<100 μg I/kg) or moderate I (930 μg I/kg). We measured thyroid gland (TG) weight, TG stable I content, TG125I uptake, and125I labeling of thyroid hormones. Triiodothyronine (T3) and thyroxine (T4) concentrations in TGs and serum were also determined. Our results indicate that doves and quail receiving the same dietary I show similar serum T3(the presumed metabolically active hormone) and TG functional state but that there are some differences between the species in the way in which this functional state is achieved.We also assessed the effects of differences in I availability on thyroid function in doves. With low dietary I doves show decreases in some measures of thyroid function (reduced serum T4and TG‐hormone stores) compared to doves with moderate I but maintain a comparable level of serumT3. This regulation of T3appears to be independent of serum T4or TG‐hormone

ISSN:0022-104X    

DOI:10.1002/jez.1402440210

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

年代:1987

数据来源: WILEY

摘要:

AbstractGolden hamster testes regress after short day exposure. The present study asks: 1) are Leydig cell numbers depleted during short days, and 2) if so, how are they replenished during recrudescence. Control hamsters were shown 14 h of light and 10 h of dark (LD 14:10) for 10 weeks (n = 12). Testicular regression was induced by LD 6:18 for 10 weeks (n = 4), and recrudescence by switching regressed hamsters to LD 14:10 for 3 and 5 weeks (n = 8 for each group). All hamsters were injected with [3H]thymidine [3 μCi/gm body wt., intraperitoneally (i.p.)]1 h or 2 weeks before sacrifice. Leydig cell number per testis was determined by stereological analysis of sections of perfusion‐fixed testes, and labeling indices were determined by autoradiography. Leydig cell numbers were reduced significantly from 18.2 × 106in control to 9.0 × 106in regressed testes (p<0.05); then increased to 14.0 × 106and 17.9 × 106in 3‐ and 5‐week recrudesced hamsters. The labeling index was nondetectable (n.d.) for regressed hamsters. In control and recrudescing hamsters the labeling index was measured at two times (t1= 1 h vs. t2= 2 weeks post‐injection): in controls, t1= 0.22 ± 0.15% (mean ± SEM) vs. t2= 0.28 ± 0.22%; in 1 week recrudesced, n.d. vs. 1.92 ± 0.77% (p<0.05); at 3 wk, n.d. vs. 4.58 ± 1.74% (p<0.05); at 5 weeks, 1.92 ± 0.61% vs. 2.25 ± 0.59%. These results are indicative of the existence of interstitial precursor cells that divide, then differentiate, and thus replenish the Leydig cell population during testi

ISSN:0022-104X    

DOI:10.1002/jez.1402440211

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

年代:1987

数据来源: WILEY