摘要:

AbstractThe submicroscopic morphology of the corpus allatum‐corpus cardiacum complex of wild type adult femaleDrosophila melanogasteris described. These endocrine organs are compared with those of females homozygous for the recessive, female sterile gene,fes.The corpus allatum is known to produce a hormone influencing vitellogenesis. The ultrastructure of the gland suggests that this hormone is synthesized by a smooth surfaced, membranous system organized into a reticulum of filaments and tubules from which vesicles are derived by abscission of terminal and lateral blebs. The allatum cells of genetically ovatectomized,fesfemales are inhibited from releasing the hormone they synthesize. They swell and undergo characteristic, degenerative changes. The corpus cardiacum consists of a central bundle of axons surrounded by cortical cells. Many of the axons are thought to originate as projections from specialized, secretory neurons residing in the pars intercerebralis. Neurosecretory spheres are carried posteriorly in these axons by traveling bulges. The cortical cells contain myriads of neurosecretory spheres suspended in their cytoplasm, and most of these are believed to have been donated by contiguous axons. Cortical cells are also characterized by an extensive, rough surfaced, endoplasmic reticulum consisting of interconnected bloated cisternae which arise from localized, blister‐like proliferations of the outer membranes of the nuclei. The cortical cells offesfemales also swell, and their nuclear blisters reach immense sizes. Vitellogenesis within a wild type ovary previously implanted into the abdomen offesfemales is accompanied by release of products from the host allatum and cardiacum cells and the return of these cells to their normal morpholog

ISSN:0022-104X    

DOI:10.1002/jez.1401610202

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

年代:1966

数据来源: WILEY

摘要:

AbstractThe ultrastructure ofT. pyriformis, strain E, is markedly influenced by the physical conditions of the medium during the growth cycle. Logarithmic growth cells contain a minimal number of mitochondria which are peripherally distributed. Rough endoplasmic reticulum (RER) is abundant and numerous primary lysosomes are scattered throughout the cytoplasm. Lipid droplets are sparse. This situation is unchanged in quiet culture flasks or those that are aerated and/or stirred. When cells enter stationary growth the physical treatment of the medium has profound effects on the cytoarchitecture. In quiet flasks the mitochondria have increased several times over that in young cultures and they are randomly distributed. Lipid droplets are abundant. Very little RER can be seen and primary lysosomes are scarce. A few autophagic vacuoles appear at this phase of growth. When the culture medium has been stirred throughout the growth cycle the ciliates appear quite different. No lipid droplets are formed; the mitochondria are few and peripherally distributed as in young cells. Primary lysosomes and RER are scarce. An occasional autophagic vacuole is observed. Aeration of the medium does not alter this cytoarchitecture. Physical activity of the cells seems to influence the distribution, number, and kinds of particulates. These observations suggest that certain metabolic processes as reflected by ultrastructure are dependent on the physical activity of the ciliates during the growth cycle.

ISSN:0022-104X    

DOI:10.1002/jez.1401610203

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

年代:1966

数据来源: WILEY

摘要:

AbstractNile blue sulfate solutions can be applied to teleost blastoderms in dosages sufficient to stain only the cellular envelope, or to penetrate uniformly from the surface to desired depths among the interior cells. Surface cells, if overstained, break loose from the cellular envelope and migrate to the interior, with subsequent failure of epiboly and differentiation. Less dosage slows down epiboly but does not disrupt organogenesis. The cellular envelope does not contribute any substantial number of cells to the terminal node or any at all to the inner germ ring. The hypoblast is not invaginated from it, nor does it contribute to the notochord, the mesoderm, or the endoderm sheet. Its fate is exclusively epidermal, and it is at all times separable from the inner blastomeres and embryonic tissues. Previously published “fate maps” of the teleost blastodisc must be understood as relating to the internal cells, not the cellular envelope. No conclusive evidence yet exists that the morphogenetic movements of teleosts include either an invagination or an inturning movement, at or inside the blastodisc

ISSN:0022-104X    

DOI:10.1002/jez.1401610204

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

年代:1966

数据来源: WILEY

摘要:

AbstractNile blue sulfate stain spots printed upon the teleost blastodisc may penetrate to deep cells. Spots printed upon the periblast just outside the rim of the early blastodisc remain stationary, and when overridden by the spreading disc may transmit their stain to cells of its floor that come progressively in contact with them. Such spots do not give reliable evidence of invagination movements, or of a wheeling‐in of cells that lie inside the cellular envelope though close to the surface. Small spots printed upon the surface at the margin of the blastodisc do not necessarily disappear from the margin, and if they do they cannot subsequently be discovered in the interior. Patterns of chalk particles injected into the blastodisc for the purpose of demonstrating the origin of the hypoblast by a wheeling‐in movement of cells at the rim have produced no such evidence, but show a direct migration of originally internal cells toward the definitive somites. Conclusions drawn from theSalmofate map and scheme of morphogenetic movements (Pasteels, '36) are not substantiated insofar as they pertain to the origin of the hypoblast and the behavior of cells at the blastodisc rim. There is no inturning of cells to produce the hypoblast, either at the axis or along the germ r

ISSN:0022-104X    

DOI:10.1002/jez.1401610205

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

年代:1966

数据来源: WILEY

摘要:

AbstractVital dye carriers implanted under the blastodisc and chalk markers injected among the blastomeres provide a new interpretation of the origin of the hypoblast in teleost embryos. This first inner layer of cells is formed along the sides of the embryonic area and around the germ ring, not by invagination from the surface, or by wheeling in of deeper cells, or by delamination at the blastodisc rim, but by the migration outward of deep central cells. The layering is interpreted as the effect of a shear between superficial cells in pure epibolic motion and deeper cells which are at the same time undergoing convergent movement toward the axis. The whole blastodisc could be stained to controllable depths by suitable exposure to vital dye solutions. Subsequent location of the colored cells indicates that at the late “pregastrula” stage the prospective CNS cells overlap those which will become the first 10 pairs of somites, and all the prospective somite material overlaps prospective notochord and endoderm. A teleost pregastrular fate map thus cannot be a surface map as in amphibia. The rim of the teleost blastodisc and the amphibian blastopore carry out totally different functi

ISSN:0022-104X    

DOI:10.1002/jez.1401610206

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

年代:1966

数据来源: WILEY

摘要:

AbstractAn inherited disturbance in egg polarity has been observed inDrosophila melanogaster.Thebicaudalabnormal embryos develop the terminal segments of a second larval abdomen in mirror‐image symmetry to the terminal segments of the normal abdomen. The two abdomens may be symmetrical with four or five segments at each end of the egg or have more abdominal segments at the normal posterior end than at the reversed end. The reversed posterior ends appear to have normal spiracles, hindgut and Malpighian tubules. The bicaudal embryos and two other specific lethal types associated with them are produced in very low frequency. The production of these lethals is associated with an unmarked second chromosome, which has been carried in three separate inbred lines in combination with a Curly, Lobe, speck balancer chromosome. Flies homozygous for the chromosome and flies heterozygous for this chromosome and a second chromosome containing a deficiency at the vestigial locus can produce the syndrome. Reciprocal crosses, of flies of a genotype which can produce the syndrome with flies which do not, have shown that the maternal genotype is the controlling factor in the production of the abnormalitie

ISSN:0022-104X    

DOI:10.1002/jez.1401610207

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

年代:1966

数据来源: WILEY

摘要:

AbstractDemembranated gastrulae that had been cultured in 0.05% cytosine arabinoside for a day and subsequently cultured in a saline medium, experienced a delay (1–2 days) in the time at which flexure of the tail‐buds first occurred. Histological sections showed these embryos to be essentially normal. Isotopic experiments revealed that cytosine arabinoside inhibited DNA synthesis, but stimulated the incorporation of C14‐uridine into RNA. There was a slight inhibition of protein synthesis. The results suggest that the reversible delay in normal development during gastrulation is primarily due to the inhibition of DNA synthesis and cell div

ISSN:0022-104X    

DOI:10.1002/jez.1401610208

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

年代:1966

数据来源: WILEY

摘要:

AbstractOxidative and hydrolytic enzymes were localized histochemically in the developing chick liver and in liver grown as chorioallantoic (CAM) transplants or as explants in organ culture.In thein situliver, parenchymal cells exhibited an increase in succinate (SDH) andaglycerophosphate (GDH) dehydrogenase activity and a decrease in NADP diaphorase (TPND) during development. NAD diaphorase (DPND) and nonspecific esterase (NSE) activity remained constantly high throughout the period studied. Within the stromal cells, DPND and NSE activity decreased and SDH, GDH and alkaline phosphatase (ALP) increased. The ALP activity of the sinusoidal cells appeared to increase coincident with a redistribution of TPND within the cytoplasm of the parenchymal cells.In CAM transplants, the enzyme activity of all tissues was nearly the same as the five day liver even though the total age of the tissues was 15 days.Liver explants exhibited enzyme activity similar in part to both the 5 and 15 day liver.In both explants and transplants, ALP activity was highest in areas where the parenchymal‐sinusoidal relationship was maintained and absent in areas where the parenchyma and sinusoidal cells were not in contac

ISSN:0022-104X    

DOI:10.1002/jez.1401610209

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

年代:1966

数据来源: WILEY

摘要:

AbstractSkin fromRana catesbeianaadults and tapoles was found to contain an unusually high concentration of inorganic phosphate which was chemically identified and histologically localized as dense granules of calcium phosphate deposited as a discrete layer at the junction between thestratum spongiosumand thestratum compactumof the dermis. Electron microscopic studies revealed that the granules were composed of fine needle‐like crystals and were not associated with cells which seemed obviously related to their genesis. Although no definite function was established for this apparently normal structure of bullfrog skin, its possible role as a reservoir of readily available calcium was suggested. As such, it would represent an important factor to be considered in studies of the biochemistry and physiology of frog skin, especially those which deal with the effects of calcium depletio

ISSN:0022-104X    

DOI:10.1002/jez.1401610210

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

年代:1966

数据来源: WILEY

摘要:

AbstractExperiments were conducted to evaluate the effects of mammalian hypophysial hormones, placental gonadotrophins, gonadal hormones, and adrenal corticosteroids on ovulation and spawning in three‐day hypophysectomized gravid catfish. Of the hypophysial hormones tested (FSH, LH, LtH, STH, TSH, ACTH, and oxytocin), at various dose levels, LH alone consistently induced ovulation and spawning of eggs; administration of 5 mg/fish evoked the best response. The weak response obtained with FSH, STH, or TSH was not due to LH contamination. HCG at a dose level of 100 IU/fish induced ovulation and spawning, whereas in the case of PMS, doses of 250 IU/fish and above were equally effective. None of the gonadal hormones tested (estradiol, testosterone, and progesterone) evoked ovulation or spawning. All the adrenal corticosteroids tested (hydrocortisone, cortisone, and DOCA) proved to be powerful ovulating agents, DOCA (5 mg/fish) being the most effective. These findings indicate that in the catfish, LH and HCG as well as adrenal corticosteroids are effective in inducing ovulation and spawning in three‐day hypophysectomized gravid catfish. The possible mechanisms involved are discus

ISSN:0022-104X    

DOI:10.1002/jez.1401610211

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

年代:1966

数据来源: WILEY