bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neural regulation of adenohypophysial prolactin secretion in tetrapods: Indications from in vitro studies
Authors: Nicoll Charles S. 
Published: June 2005

AbstractThe in vitro prolactin‐secreting capacities of adenohypophyses of Columba livia (pigeon) and Necturus maculosus (salamander) were compared with those of living and dead rat adenohypophyses over an eight‐day culture period. The living rat adenohypophysis produced prolactin at a constantly high rate. The dead rat tissue showed no evidence of active prolactin secretion. The secretion rate of prolactin by the pigeon adenohypophysis decreased rapidly with time in vitro and closely resembled the performance of dead rat adenohypophysis. Necturus adenohypophysis showed a slight initial decrease in prolactin secretion rate, which then plateaued at a constantly low level. The effects of acid extracts of cerebral and hypothalamic tissues of Agelaius tricolor (blackbird) on prolactin secretion in vitro by Agelaius adenohypophysis were examined. The extract of cerebral tissue had no effect, but the hypothalamic extract increased prolactin secretion, indicating that the blackbird hypothalamus contains a stimulator of prolactin secretion. These results indicate that the neural mechanism which controls prolactin secretion in Columba and Agelaius is different from that which exists in rats and other laboratory mammals. No definite conclusions can be drawn regarding neural regulation of prolactin secretion in Necturus.
Thyroid‐gonad relationship in spotted munia, Uroloncha punctulata
Authors: Thapliyal J. P. , Pandha S. K. 
Published: June 2005

AbstractThyroidectomy of adult Spotted munia (Uroloncha punctulata) leads to the gonads remaining permanently in full breeding condition and is responsible for an early increase in testis size and activity in juvenile birds. These effects may be due to (i) general disturbances in metabolism or (ii) continuous secretion of gonadotropic hormones from the hypopyhsis or (iii) to both of these processes.
An investigation on the swimming reaction of the anemone Stomphia coccinea. I. Partial isolation of a reacting substance from the asteroid dermasterias imbricata
Authors: Ward Jack A. 
Published: June 2005

AbstractBehaviorally the sea anemone, Stomphia coccinea, is an unusual actinarian compared to other members of the Actinaria. When the asteroid, Dermasterias imbricata, is brought into contact with Stomphia it responds by propelling itself through the water by a series of whip‐like swimming motions.Tissue homogenates from the aboral surface of Dermasterias proved to be as effective as the entire animal. Homogenates from all other tissues gave negative results. The substance which causes the swimming response is dialyzable, thermostable, and from qualitative tests proved to be primarily carbohydrate. Acidic hydrolysis (HCL) of the polysaccharide revealed three definitive products. Enzymatic hydrolysis by hemicellulase yields the same compounds but caused a complete degradation of the substance. Chromatographic results showed that the compounds are probably products from an amino‐polysaccharide.
RNA and DNA synthesis during activation and secretion of the prothoracic glands of saturniid moths
Authors: Oberlander Herbert , Berry Spencer J. , Krishnakumaran A. , Schneiderman Howard A. 
Published: June 2005

AbstractThe present work analyzes the mechanism of activation of the prothoracic glands in larvae and pupae of saturniid moths, and examines changes which occur in the prothoracic glands during the larval‐pupal and pupal‐adult transformation.The prothoracic glands of Samia cynthia ricini and Antheraea polyphemus synthesize DNA in the fourth instar. DNA synthesis occurred to a lesser extent in the fifth instar and in prepupae, but was not found in diapausing pupae or developing adults. Injury to diapausing pupae did not stimulate DNA synthesis in the prothoracic glands. The prothoracic glands of pupae of A. polyphemus injected with juvenile hormone extract did not synthesize DNA, nor did the prothoracic glands of pupae of Samia cynthia walkeri after transplantation into larvae. Apparently the prothoracic glands lose their ability to synthesize DNA during the larval‐pupal transformation.The prothoracic glands of larvae of S. cynthia ricini synthesized RNA at a high rate throughout the fourth larval instar. In A. Polyphemus the rate of RNA synthesis in the prothoracic glands of developing adults was several times greater than the rate of RNA synthesis in diapausing pupae. The injection of juvenile hormone extract into pupae of A. polyphemus caused a marked increase in the rate of RNA synthesis. Changes in the rate of RNA synthesis were correlated with cytological changes in developing adults and in pupae injected with juvenile hormone extract.Prothoracic gland cells were found in adult S. cynthia ricini. Some of the cells were degenerating while the others appeared inactive.The relationship of RNA synthesis to activation and secretion, and the significance and control of DNA synthesis in the prothoracic glands are considered. Preliminary work on protein synthesis on the prothoracic glands and their activation in vitro is evaluated.
The effect of nucleic acid antagonists on cell division and oral organelle development in Tetrahymena pyriformis
Authors: Frankel Joseph 
Published: June 2005

AbstractThe effects of 5‐fluorodeoxyuridine, 5‐fluorouridine, actinomycin D, and p‐fluorophenylalanine on cell division and oral morphogenesis in both exponentially growing and synchronized Tetrahymena pyriformis GL were investigated. All of the inhibitors tested were capable of preventing and/or greatly delaying cell division in both growth situations. Associated with the block of cell division, there were pronounced effects on oral morphogenesis. Following addition of any one of the inhibitors to an exponetially growing culture, the proportion of cells with developing oral primordia (particularly primordia in the process of membranelle formation) declined sharply, and there appeared, after some time, primordia with oral membranelles in the process of resorption. In synchronized cultures, the effects of the inhibitors on specific developmental stages were followed with more precision. Development continued for about 30 minutes after addition, and then stopped in most of the cells. In cells which were undergoing membranelle formation (developmental stages 3 and 4) at the time when the inhibitor took effect, development was halted and oral primordia were resorbed. On the other hand, cells in which membranelle formation was complete or nearly so (stages 5 and 6) continued to develop and eventually divided. Stabilization occurred at late stage 4 with respect to all of the inhibitors considered in this study, as well as with high and low temperatures, considered earlier.At inhibitor concentrations just below those required to permanently block development in all cells, renewed development in some cells was observed several hours after addition of the agent. The oral structures formed during this period were always normal in both size and internal pattern. In this respect the effects of the chemical inhibitors differ from those of high temperature, which not only interferes in the maintenance of development, but also brings about abnormalities in spatial pattern.The following conclusions may be drawn from these studies: (a) both protein and template RNA synthesis must take place during the process of oral development in order to maintain further development; (b) the pattern and size of the oral structures that are formed is not affected by limitation in the supply of protein and RNA precursors.
Fine structure of the free cell surface in developing mouse intestinal mucosa
Authors: Overton Jane 
Published: June 2005

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.
Cultivation of the life stages of Aurelia aurita under controlled conditions
Authors: Spangenberg Dorothy Breslin 
Published: June 2005

AbstractThe life stages of Aurelia were raised under controlled conditions in a chemically defined salt solution. Scyphistomae have thrived for three years in this medium, budding and strobilating normally. Ephyrae developed into mature medusae within a four month period. A description of all the life stages of a known species of jellyfish was obtained for the first time.Laboratory cultured medusae underwent developmental changes very similar to medusae in nature. The development of new structures occurred in a chronological sequence which consistently appeared in this order: marginal veil and oral arms, circular canal, margin tentacles, marginal lappets and special sensory lappets, subgenital pits, eight‐partition scalloping of the bell, ruffling of the oral arms, and sexual products. Gastric filaments, nematocysts and mesogloea continually increased in number and amount throughout development.Laboratory cultured medusae differed from those developing in nature in that they (1) reached a maximum growth of 55 mm at the time of sexual maturation, (2) did not develop as many tentacles at the bell margin, and (3) did not yield as many planulae.It was not possible to correlate closely either the age or size of the medusae with the development of any specific morphological structure.All medusae underwent spontaneous deterioration. The extrusion of gastric filaments along with the release of sexual products indicated that medusae may starve to death since gastric filaments are believed necessary for digestion of food.The flexibility and variety of growth systems occurring in Aurelia under controlled conditions provide new opportunities for the study of basic mechanisms involved in normal and abnormal growth.
Autonomy of fu and fu59 ovarian implants with respect to rate of tumor production
Authors: Smith P. A. , Bodenstein D. , King R. C. 
Published: June 2005

AbstractThe ovaries of females homozygous for any of the mutant alleles of the fused gene produce tumorous chambers. Tumor incidence increases with age, and the frequency of tumors in fu ovaries 0–12 days of age is six times that observed in the ovaries of fu59 females of the corresponding age. Ovaries of fu/fu and fu59/fu59 females were transplanted into hosts homozygous for the + allele of fused to determine if the extra‐ovarian environment has any relation to the rate at which tumors appear. The rates remain the same in each case indicating that the rate is a genetic characteristic of the cells of the ovary and is not affected by the extra‐ovarian environment.
The fine structure of the sperm of a tunicate, Ascidia nigra
Authors: Schabtach Eric , Ursprung Heinrich 
Published: June 2005

AbstractThe ultrastructure of the spermatozoon of Ascidia nigra is described. The head of this sperm contains an elongated nucleus flanked and surrounded by a single large mitochondrion. No other mitochondria are present. An acrosome is seen to extend over a large portion of the nucleus. The tail shows the typical 9 + 2 arrangement of fibrils, and in some region carries fins.
Effect of dosage on the survival of embryonic homotransplants in the leopard frog, Rana pipiens
Authors: Volpe E. Peter , Gebhardt Bryan M. 
Published: June 2005

AbstractA widespread conviction is that embryonic primordia may be successfully homotransplanted between amphibian embryos without any subsequent antagonism of an immune nature between host and graft tissues. Presumably the grafting of embryonic rudiments prior to the maturation of the immunological machinery of the host has the effect of prolonging, seemingly indefinitely, the survival time of the graft. It now can be shown, at least in the leopard frog, that an embryonic (neural fold) homograft can induce either immunity or tolerance, the given response being largely governed by the amount of tissue that is transplanted. Tolerance is not at all guaranteed simply by exposing the host to an antigenic stimulus before the functional differentiation of the immune system. Indeed, small quantities of homografted neural fold tissue confer immunity, not tolerance. The host's reactive system can only be suppressed by a large dose of transplanted neural fold material.
Relationships between body weight and skull development in rats raised in enriched and impoverished conditions
Authors: Diamond Marian C. , Rosenzweig Mark R. , Krech David 
Published: June 2005

AbstractRats experiencing an enriched environment develop a heavier, thicker visual cortex than rats living in an isolated condition (Bennett et al., '64). The present experiment was carried out to determine if these enriched‐environment animals also possessed a larger neurocranium.Eleven pairs of male littermate rats from the S1 strain were used in Experiment I and ten pairs in Experiment II. At 25 days of age one animal of each littermate pair was placed in an enriched environment, and his brother was assigned to an isolated condition. Roentgenograms were taken eight days after the animals entered their respective conditions and again 69 days later. Skeletal measures were made from the roentgenograms, and endocasts were also made.The intracranial dimensions and the endocast weights did not differ significantly between the two experimental groups. However, other aspects of skull development, e.g., bizygomatic width, maxillary width, and skull weight did differ significantly, with the isolated animals having the greater measures. The differences in the skulls appear simply to reflect differences in body weight with a positive correlation between body weight and facial bone development in both young and old animals. The positive correlation between body weight and cranial size in young animals is not maintained in old animals.
A histochemical analysis of lipid yolk deposition in the oocytes of cat and dog
Authors: Guraya Sardul S. 
Published: June 2005

AbstractVarious cell components such as yolk nucleus, loose basophilic substance, mitochondria and lipid bodies (L2) proliferate with the growth of previtellogenic oocytes in cat and dog, investigated with various histochemical techniques. The yolk nucleus and its fragments consist of RNA, protein and some lipoprotein. The loose basophilic substance reacts mainly for RNA and protein. The mitochondria show phospholipid and protein. The lipid bodies (L2) contain phospholipid. The sites of distribution of lipid bodies (L2) and vacuoles in the oocytes and granulosa suggest a nutrient transfer design. Some large vacuoles, which react negatively with the various techniques used, gradually accumulate in the central cytoplasm of large oocytes which abundantly store sudanophilic lipid yolk droplets of various sizes. These consist mainly of phospholipid and neutral fat (triglyceride); the latter increases in amount during atresia of oocytes. They are formed by the coalescence and condensation of small lipid granules whose precursors appear to be transported from outside the oocyte, as judged from the corresponding infiltration of lipids through the zona pellucida into the oocyte. The incoming lipids are physicochemically changed before they are converted into lipid yolk droplets. This change may be brought about by the peripheral cell organelles (mitochondria and yolk nucleus substance) and ground cytoplasm. The direct transformation of cell organelles into lipid yolk has been ruled out in the present material.
Cytophotometric evidence for triploidy in hybrids of the gynogenetic fish, Poecilia formosa
Authors: Rasch Ellen M. , Darnell Rezneat M. , Kallman Klaus D. , Abramoff Peter 
Published: June 2005

AbstractAmounts of DNA per nucleus were estimated by microphotometry in Feulgen‐stained tissue sections from several species of poeciliid fish and their hybrid offspring. In terms of average nuclear volumes as well as relative DNA levels, the all‐female gynogenetic species P. formosa was indistinguishable from the related bisexual species P. sphenops, confirming the essentially diploid nature of the amazon molly, P. formosa. Although DNA values from the less closely related species P. vittata were about 15% higher than those from P. sphenops, both species showed expected patterns of DNA behavior in several somatic tissues and in developing male sex cells.Somatic nuclei from two types of interspecific hybrids contained more DNA than corresponding types of nuclei from typical maternal P. formosa, the additional amount being equivalent to the haploid DNA value characteristic of the participating paternal species. The results strongly suggest that these hybrids are genetic triploids, probably containing diploid maternal and haploid paternal chromosome contributions. The high incidence of chromosomal stickness, bridging, and fragmentation observed during metaphase I of spermatogenesis, and the occurrence of both “giant” and “micro” spermatids in testis of the hybrid P. formosa X P. vittata may well account for the apparent sterility of amazon molly offspring which show transmission of paternal characteristics.Production of triploid interspecific hybrids in poeciliid fish and corollary implications for interpreting previous tissue transplantation studies are discussed.
The effect of Co60‐radiation on development and DNA synthesis in the 11‐day rat embryo
Authors: Skalko Richard G. 
Published: June 2005

AbstractFemale albino rats of a Wistar strain were exposed to either 135 r or 270 r of Co60‐radiation on the morning of day 11 (Witschi stage 17). Autopsy on day 20 revealed that the lower dose produced a slight increase in the degree of resorption, no effect on fetal weight and no malformations in the survivors. The higher dose, on the other hand, produced a large increase in the degree of resorption, a pronounced effect on fetal weight and many malformations.Radioactive phosphorus (P32) was injected into irradiated and non‐irradiated pregnant females to study DNA synthesis in individual litters after irradiation. Isotopically‐labeled DNA was extracted from embryo homogenates by a modified Schmidt‐Thannhauser procedure. DNA synthesis was suppressed in both series of irradiated embryos at 3, 6 and 12 hours after irradiation, the higher dose producing the larger amount of suppression. At 24 hours after irradiation, no significant difference was observed in the degree of DNA synthesis in control and irradiated embryos. No difference was observed between the specific activity of P32 in the acid‐soluble fractions of placenta and embryo in control and irradiated litters, indicating that suppression of DNA synthesis reflected a change in the cellular population which is synthesizing DNA. Histological criteria indicate that this initial effect is cellular death and that the embryo compensates for this damage by regulatory processes.
The effects of actinomycin D and ribonuclease on oral regeneration in Stentor coeruleus
Authors: Whitson G. L. 
Published: June 2005

AbstractContinuous exposure to a high concentration of actinomycin D (250 μg/ml) completely inhibits oral regeneration in amputated tail pieces of Stentor coeruleus. Once oral regeneration is initiated, the same concentration of actinomycin D no longer inhibits normal regeneration. Concentrations of actinomycin which inhibit complete regeneration also inhibit incorporation of H3‐cytidine into RNA.Ribonuclease (1 mg/ml) completely inhibits normal oral regeneration in posterior pieces exposed continuously to this enzyme. Pretreatment of whole stentors with ribonuclease completely inhibits regeneration in cells exposed continuously for two hours but only partially inhibits it in cells exposed for shorter periods. During the same two‐hour period, cytoplasmic RNA is reduced to about a third its normal value. The results suggest that both newly formed (messenger?) and preexisting (ribosomal?) RNA are necessary for regeneration.During the last 3–4 hours of regeneration posterior pieces slough off developing oral anlagen as a result of addition of 1 mg/ml of ribonuclease. This sloughing of oral anlagen may indicate either a loss of RNA needed to maintain oral regeneration or a general response to injury.
Chromatophore control and the cephalic neurosecretory system in the burrowing shrimp, Upogebia major De Haan
Authors: Oguro Chitaru 
Published: June 2005

AbstractThe red chromatophores of Upogebia major are concentrated by the injection of extracts from the sinus gland and the supraesophageal ganglia but not by the eyestalk extract. The former two cause dispersion of dark pigment of Idotea japonica but the eyestalk extract is ineffective. The sinus gland and the optic medulla lie in the cephalon. In the eyestalk, a structure is present which is considered to be homologous with the sensory pore x‐organ of macruran decapods. Evidence of secretory activity by certain cells in the sensory pore x‐organ has been adduced.
Re‐investigation of the possible occurrence of maternally induced tolerance in guinea pigs
Authors: Billingham R. E. , Silvers Willys K. 
Published: June 2005

AbstractThe possibility that an immunological tolerance of maternal skin homografts may be acquired naturally in guinea pigs as a consequence of the accidental incorporation of maternal cells into the fetuses has been re‐investigated. F1 hybrids between two isogenic strains, 2 and 13, were reciprocally backcrossed to strain 13 animals to produce two genetically heterogeneous populations which differed only insofar as those animals which had developed in an F1 hybrid uterine environment had had an opportunity to incorporate strain 2 cellular antigens ante partum.To test for any altered immunological reactivity this might have caused, both populations of animals were challenged with strain 2 skin homografts when they were 30 days of age. Although two of 192 offspring of F1 mothers failed to reject their grafts during the 200 day observation period, the distribution of survival times of the remaining grafts in this group of animals was very similar to that of the grafts transplanted to 167 offspring of strain 13 females.It is concluded that the two exceptional cases are most probably the result of chance antigenic compatibility and that maternally acquired tolerance is a very rare phenomenon in guinea pigs, if it occurs at all.
Aggregation of chemically dissociated sponge cells in the absence of protein synthesis
Authors: Humphreys Tom 
Published: June 2005

AbstractPuromycin and ethionine immediately inhibit protein synthesis more than 90% in chemically dissociated sponge cells. Initial aggregation proceeds normally in the presence of both inhibitors, indicating that protein synthesis is not necessary for the aggregation of these cells. After six hours in puromycin, the cells stop aggregating and die. In ethionine, the cells aggregate and remain aggregated for at least 48 hours, although protein synthesis remains repressed. Thus protein synthesis is not necessary for producing the material which binds these cells together. Although the aggregation is not dependent on concurrent protein synthesis, it was conceivable that protein which was stored in the cell was secreted during aggregation. However, sponge cells could aggregate over and over in ethionine, indicating that the cells were not dependent on a stored supply of material.