bluuebunny/crossref_metadata_2025 huggingface dataset:
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

The 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

The 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

Dimensions 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

The 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

The 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

The 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

A 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

Rats 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

Various 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

Amounts 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

Female 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

Continuous 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

The 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

The 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

Puromycin 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.
A Photoperiodic influence on growth in rats
Authors: Young D. A. B.
Published: June 2005

In otherwise identical conditions, weanling male rats were found to gain weight more slowly over a period of 5 to 6 weeks when the day length of artificial light was reduced from 12 hours by daily decrements of up to five minutes than when kept on a constant day length of 12 hours. In the several experiments performed the differences were highly significant and the overall reduction in weight gain was of the order of 10%. No appreciable changes were found in either food consumption or final body composition. No such difference in weight gain was observed in the same experiments when the animals were kept singly in cages, which caused a greatly increased food consumption and gain in weight. Rats kept on a constant day length of eight and one‐half hours showed the same weight gain as those kept on a 12‐hour day. The difference in weight gain was also found in a simultaneous comparison of growth in male weanling rats kept on a constant 12‐hour day of artificial light and rats kept in the natural lighting conditions of late autumn.
In vitro fertilization of rabbit ova
Authors: Brackett Benjamin G. , Williams William L.
Published: June 2005

A repeatable procedure for in vitro fertilization of rabbit ova in which the percentage of ova fertilized is consistently high has been developed. When ova were recovered and subsequently incubated in vitro with capacitated spermatozoa at 37° or 39°C levels of ova fertilized were 15, 24 and 28% when 73–78%, 83%, and 90% relative humidities, respectively, were maintained. Twenty‐one per cent of all ova in these experiments were fertilized. When the ova were recovered at 30–39°C and subsequently incubated at 37° or 39°C with capacitated spermatozoa under paraffin oil only 19% of the ova were fertilized. However, when ova were recovered and subsequently incubated with capacitated spermatozoa and fluids from the female tract all under paraffin oil at 39°C with 96–97% relative humidity levels of ova fertilized were 30, 32 and 73% when stored oviduct fluid, stored uterine fluid, and fresh uterine fluid, respectively, were included in the media. Thirty‐seven per cent of all ova incubated with capacitated spermatozoa under paraffin oil were fertilized. This system with the inclusion of fresh uterine fluid in the medium yields the highest percentage of fertilization with greater consistency than any other system for in vitro fertilization of rabbit ova ever reported.
In vitro studies on 35S‐sulfate incorporation into the acid mucopolysaccharides of chick embryo cardiac jelly
Authors: Gessner Ira H. , Boström Harry
Published: June 2005

An experimental model has been devised for the study of radioactive sulfate incorporation into the cardiac jelly of the isolated stage 18–19 (three‐day) chick embryo heart. Isotope incorporation was found to be optimal in an incubation medium containing glucose, but containing no added unlabeled sulfate. The rate of isotope uptake demonstrated a slight lag during the first 5 to 10 minutes followed by a linear incorporation of at least four hours duration. It is believed that 35S‐sulfate incorporation into the hearts reflects sulfated acid mucopolysaccharide synthesis, and that this system will therefore be useful in studying the significance of this group of compounds in the cardiac jelly.

Radioactive sulfate incorporation per unit weight has been found to be inversely proportional to heart weight (i.e., embryo age) over the span of development from stage 14 to stage 24. This probably reflects the fact that cardiac jelly makes up proportionately a greater part of the younger hearts.

Sodium salicylate has been shown to inhibit 35S‐sulfate incorporation in this system, in direct relation to its concentration in the incubation medium. This is given as one example of the type of investigation to which this system is adaptable.
Acid mucopolysaccharide content of the cardiac jelly of the chick embryo
Authors: Gessner Ira H. , Lorincz Andrew E. , Boström Harry
Published: June 2005

Investigations of the stage 16 to 19 chick embryo have been performed specifically in relation to the composition of cardiac jelly. Biochemical analysis has demonstrated the presence of a non‐dialyzable sulfated mucopolysaccharide, containing hexosamine and uronic acid. This material can be complexed with cetylpyridinium chloride, and then exhibits differential salt solubility in accordance with known characteristics of acid mucopolysaccharides, suggesting that the chondroitin sulfates and heparin‐like compounds are the major sulfated components. Histochemical and 35S‐sulfate incorporation studies also support the interpretation that cardiac jelly contains a significant amount of sulfated acid mucopolysaccharide.
Vitally stained kappa in Paramecium aurelia
Authors: Mueller Jo Anne
Published: June 2005

Purified kappa particles stained with methylene blue were placed into fluid containing paramecia. The vitally stained kappa quickly aggregated in food vacuoles of both sensitive and killer animals. A few filamentous projections were observed protruding into the cytoplasm from vacuoles containing kappa. Occasionally food vacuoles packed with stained particles would disrupt and the contents would disperse throughout the cytoplasm. Paramecia with stained kappa in their food vacuoles were disrupted and the vacuolar contents examined. Virtually all of the kappa from the vacuoles were N particles. Among the thousands of particles observed, only a few B particles were detected.
The duodenal progenitor population. III. The progenitor cell cycle of principal, goblet and paneth cells
Authors: Thrasher J. D. , Greulich R. C.
Published: June 2005

The duodenal progenitor population has been investigated with tritium thymidine (H3‐T) and autoradiography in male Swiss albino mice to characterize the role that individual cell types (principal, goblet, and Paneth) have in the proliferative activity of the duodenal crypt of Lieberkühn.

Incorporation of H3‐T into newly synthesized DNA of all three cell types was observed by one‐half after injection of the isotope. Labeled principal and goblet cells were distributed from the first cell of the cryptal mouth to the last cell at the cryptal base. The majority of labeled cells was found in the central region of the crypt Labeled Paneth cells were restricted to the last four cells at the cryptal base.

Analysis of the percentage of labeled metaphase and mitotic figures after H3‐T administration showed that the progenitor cycle duration of principal and goblet cells was about 15 hours, while that of Paneth cells was approximately 80 hours. The mean S‐phase duration was 7.4, 7.4 and 8.7 hours for principal, goblet, and Paneth cells, respectively. Thus, the G1 portion of the cell cycle was considerably longer for Paneth cells, while all phases of the progenitor cycle were of the same duration for principal and goblet cells.

It appears from the data that the three cell types of the adult duodenal crypt comprise independent populations capable of self‐renewal. Our observations also suggest the existence of causal relationships between the positioning of the proliferative cells types in the duodenal microenvironment and their respective cycle durations.
In vivo culture of Drosophila melanogaster embryos containing the notch deficiencies Df(1)N8 and Df(1)N264‐40
Authors: McCrady Edward
Published: June 2005

Male Drosophila melanogaster embryos inheriting deficiencies of the Notch series on the X‐chromosome fail to hatch from the egg, and are characterized in part by almost complete lack of differentiation of the mesoderm. In order to determine the developmental capacities of these tissues, male embryos containing N8 and N264‐40 deficiencies were cultured in vivo in the hemocoeles of wild‐type D. melanogaster larvae and adults. After periods of five and 12 days, the Notch embryos were compared with similarly cultured wild‐type control embryos. The deficient embryos of both types revealed considerable growth. The mesodermal derivatives muscle, fat, and gonad sheath were well differentiated. In every case, embryos of the short deficiency, N264‐40, grew to a greater size than did those of the much longer deficiency, N8. They generally did not exceed the size attained by normal embryos cultured for the same length of time. The growth of transplants in larval hosts always exceeded that seen in adult hosts in the same period of time. Neither of the types of deficient embryos was able to molt in either type of host, although control embryos always molted in larval hosts. The results indicate that the mesodermal tissues of Notch embryos are capable of further differentiation than they are able to exhibit in their own environment, and that the genetic materal within the extent of the N8 deficiency may be involved in their capacity to grow in culture.
Synchronization of Oral Primordia in Stentor coeruleus
Authors: Tartar Vance
Published: June 2005

By grafting and other micrurgical operations, cells and cell‐systems bearing two oral regeneration primordia initially in different phases of development can be produced. There is a strong tendency for the two anlagen to synchronize their developments and complete the later stages of oral differentiation together. The minority of cases, which failed to synchronize the developing primordia, indicated the limits of this coordination and always revealed prominent interaction between the graft components. A simple substrate hypothesis will probably not explain the results. Conclusions are that the oral primordium, once initiated, does not develop autonomously at its own intrinsic rate, and that a cell or fusion of cells performing the same process (elaboration of feeding organelles) in two different places within the system, strongly tends not to do so out of phase but synchronously.
An ultrastructural study of the effects of aeration and physical activity on aging in Tetrahymena pyriformis
Authors: Elliott Alfred M. , Travis David M. , Work Janis A.
Published: June 2005

The ultrastructure of T. 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.
The role of the cellular envelope in the morphogenetic movements of teleost embryos
Authors: Ballard William W.
Published: June 2005

Nile 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 rim.
Origin of the hypoblast in Salmo. II. Outward movement of deep central cells
Authors: Ballard William W.
Published: June 2005

Vital 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 functions.
Reversible delay of normal development of frog embryos by inhibition of DNA synthesis
Authors: Flickinger R. A.
Published: June 2005

Demembranated 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 division.
Histochemical localization of acid phosphatase in the Ovary of Gerris remigis Say (Hemiptera)
Authors: Cone M. Virginia , Eschenberg Kathryn M.
Published: June 2005

The localization of acid phosphatase in the telotrophic ovary of the water strider, Gerris remigis, has been studied by light microscopy, utilizing a simultaneous coupling azo dye technique on frozen sections. The enzyme is demonstrable in the cytoplasm of advanced nurse cells, and to a variable degree in the trophic core. Reactivity is also distributed throughout the cytoplasm of young (germarial) oocytes. As oocytes enlarge and pass into the vitellarium, reactivity becomes confined to a peripheral band, which widens and becomes associated with a peripheral accumulation of preyolk bodies. This reactivity disappears from the ooplasm before vitellogenesis is entirely completed. Oocytes which undergo degeneration before completing maturation display large, internal, phosphatase‐reactive areas.

Acid phosphatase is first demonstrable in follicle cells at the onset of vitellogenesis. Variations in its intensity and intracellular localization are in conformity with previous suggestions in the literature that follicle cells are implicated in vitellogenesis and in subsequent chorion elaboration. Following ovulation, the follicle cells become intensely reactive and as they degenerate, some of this reactive material is expelled from the ovary through the follicle cell basal surfaces. Reactive residues accumulate in the yellow body at the base of the ovary. Thus the enzyme localization is correlated with physiological autolysis in nurse cells and post‐ovulatory follicle cells and with pathological autolysis in oocytes. Its localization in normally developing oocytes and follicle cells suggests involvement in the process of vitellogenesis and chorion formation as well.
Atypical transovarial transmission of sex ratio spirochetes by Drosophila robusta sturtevant
Authors: Williamson David L.
Published: June 2005

The pattern of transmission of Sex Ratio spirochetes to the progeny of Drosophila robusta females that had been injected with spirochete‐laden hemolymph was studied. Males appeared with about the same low frequencies in all the broods, but spirochetes were transmitted in high frequencies only to the early brood progeny, the transmission to later progeny being greatly reduced. This pattern is in striking contrast to that observed in D. melanogaster and D. pseudoobscura females in which males appear in nearly equal numbers along with females in the early broods, when the frequency of spirochete transmission is low, but disappear completely from the later broods, when all the females possess a dense population of spirochetes in their hemolymph.

The transmission pattern in D. robusta supports the idea of a separation between the spirochete itself and the factor responsible for male lethality.
On the application of immunological techniques in geographic group studies of Atlantic sea herring, Clupea harengus. I. Neutralization of immune precipitins as an aid to herring serum analysis by immunoelectrophoresis
Authors: Di Capua Richard A.
Published: June 2005

The sera of Atlantic sea herring, collected from 13 contiguous oceanic locations, were analyzed by immunoelectrophoresis for precipitinogen differences. An immune serum (rabbit) against the sera from each location was required. Electro‐phoretic characteristics suitable for identifying the geographic origins of herring sera were not detected. Immune serum aliquots were therefore individually neutralized with undiluted or one of a series of dilutions of herring serum from each geographic location prior to analysis. The use of undiluted serum resulted in complete precipitin neutralization regardless of its origin. Equivalent dilutions of each serum resulted in varying degrees of precipitin neutralization. This capacity of origin‐separate precipitinogens appears to be related to the geographical distance separating the origins of immunizing and neutralizing sera, i.e., the greater the distance the higher the concentration necessary for equivalent neutralization. Sera of unknown origins can be related to sera from specific origins by comparison at equivalent dilutions for equivalent precipitin neutralization, providing they originate from the overall area sampled. Immunoelectrophoretic results are consistent regardless of sex, number of individuals contributing to the sample or the collection date. Herring precipitinogens are identified by comparison with the well‐established mobilities of human precipitinogens and are discussed based on the frequency with which they are associated with geographic group differences.
Limb regeneration and nerve fiber number in Rana sylvatica and Xenopus laevis
Authors: Rzehak Karol , Singer Marcus
Published: June 2005

Adult Rana sylvatica does not regrow an amputated forelimb whereas Xenopus laevis does. This difference in regenerative behavior has been analyzed in terms of the number of nerve fibers available at the amputation surface because previous studies have shown that nerve fibers must satisfy a quantitative threshold in order that regeneration occur. Our results show that Xenopus has more fibers per unit area than Rana. However, the value for both is far below that of Triturus and, indeed, even lower than that of the mouse. The relative scarcity of fibers in the anuran limb thus brings into question the direct relation previously drawn between nerve number and regenerative capacity in vertebrates. However, anuran nerve fibers are much larger fibers than those of other vertebrates; and, indeed, those of Xenopus surpass in size the fibers of the vertebrates we have investigated. Initial studies show that if the size of fibers is taken into account and the inneryation is expressed as amount of neuroplasm available at the amputation surface rather than as the number of fibers, the limb of Xenopus is then as richly innervated as the limb of Triturus whereas that of Rana contains much less nervous substance.
Hypophysial cysts in a teleost fish
Authors: Schreibman Martin P.
Published: June 2005

In an investigation of six stocks of platyfish (Xiphophorus maculatus) in the Genetics Laboratory of the New York Zoological Society, only one exhibited pituitary cysts. Cysts were discovered in 58 of 76 (76%) of the fish of the Gp (Grijalva) strain that were one month or older. This strain originated from the Rio Grijalva, Mexico, and has been inbred for many generations in this laboratory.

Cysts were first seen shortly after birth and they increased in size with age. This enlargement results from an increase in the number of typical goblet cells that form the wall of the cyst and by an accumulation of their PAS — positive secretion. More than one cyst rarely occurs in a gland. Cysts may be found in all portions of the adenohypophysis, most frequently in the meso‐adenohypophysis, but they never occur in the neurohypophysis. Hypophysial cysts were not found in Gp embryos, in offspring of crosses between Gp females and males from other platyfish stocks and in wild‐caught fish from the Rio Grijalva. Fish of the Gp strain that showed abnormal gonadal development always possessed a pituitary cyst, but not all fish with pituitary cysts were hypogonadal.

The information presented points to the fact that the origin of cysts has a genetic basis and perhaps arose as a result of inbreeding. It is suggested that cysts result when cells of the adenohypophysial anlage fail to differentiate into pituitary cells but become goblet cells instead.
Rejection of skin homografts in larvae of Rana pipiens
Authors: Bovbjerg Ann M.
Published: June 2005

Larvae of the leopard frog, Rana pipiens, regularly reject skin homo‐grafts. Grafts from sibling larvae show initial signs of necrosis later than grafts from non‐siblings; grafts between very young feeding larvae also show initial necrosis later than those between older larvae. Homograft rejection pattern is essentially the same in larvae of stage IV and older, in hypophysectomized larvae, and in larvae immersed in thyroxine for two weeks after grafting. Second grafts from the same donor are necrotic 4 to 5 days before first grafts are. The conclusion is drawn that destruction of skin homografts in frog larvae is independent of metamorphic phenomena, and is an immunologic reaction, possibly involving the thymus gland. The weakened response of very young larvae may reflect an immunologic mechanism that is not yet mature.
A quantitative comparison of the growth of the embryonic chick tibiotarsus in vivo and in vitro
Authors: Schryver Herbert F.
Published: June 2005

The increase in length, wet weight, dry weight, DNA content and chondroitin sulfate content of the tibiotarsus of the embryonic chick has been compared in vivo and in vitro on a chemically defined medium. Both the rate and magnitude of increase were lower in tibiotarsi in organ culture than those in the whole animal.

Comparison of ratios of various growth responses gave some indication of the mode of growth in the two situations. The dry weight/wet weight ratio of tibiotarsi in vivo remained virtually unchanged during the growth period in this study, while the ratio of tibiotarsi in vitro declined continually during the cultivation period. The hydration of skeletal elements growing in culture is probably due to degenerative phenomena. The ratio of dry weight to DNA showed that the cells of tibiotarsi in culture did not synthesize dry matter as rapidly as those in the whole chick. On the other hand, the ratio of chondroitin sulfate to DNA indicated that the cells of tibiotarsi in culture were producing chondroitin sulfate at a rate similar to that in vivo. Furthermore, the proportion of chondroitin sulfate in vitro tended to be greater than in the chick embryo. These findings suggest that the matrix of skeletal elements growing in culture, although chondroitin sulfate rich, may be deficient in one or more matrix components.
Motility in the chick embryo in the absence of sensory input
Authors: Hamburger Viktor , Wenger Eleanor , Oppenheim Ronald
Published: June 2005

The following experiment was designed to test the role of sensory input in the motility of the chick embryo: Complete deafferentation of the leg level was accomplished in 2‐day embryos by extirpation of the dorsal half of the lumbar spinal cord including the precursor cells of spinal ganglia; and simultaneous extirpation of the entire spinal cord in the thoracic level to exclude sensory input from more rostral levels. In control embryos, only the thoracic gap was made. The embryos were reared to eight and one‐half, 11, 13, 15 and 17 days, respectively, and manual recordings were made of the leg motility before the embryos were sacrificed. It had been reported by us that the motility of normal chick embryos is periodic, activity phases alternating with inactivity phases. Both the overall activity, i.e., percent of activity during a standard 15‐minute observation period, and the durations of activity and inactivity phases were found to be the same in experimental embryos and in control embryos with thoracic gaps, at least up to and including 15‐day embryos. Histological checks showed the complete absence of lumbar spinal ganglia in the majority of embryos and, the presence of a few small thoracic ganglia in some cases. All embryos with lumbar ganglia were discarded. The motor roots formed a normal plexus, and the pure motor nerves emerging from it showed a normal peripheral distribution and muscle innervation. It is concluded that the leg motility results from autonomous discharges of the lateral motor or internuncial neurons, and that sensory input is not necessary for the triggering, the maintenance or the periodicity of the leg motility. A sharp decline of motility was observed in 17‐day embryos. A study of the histological condition of the residual spinal cord showed a numerical depletion and partial degeneration of the lateral motor column. This deterioration is considered to be responsible for the functional impairments.

The implication of these results for the widespread notion that “self‐stimulation” and similar “experiences” during embryonic development play an important role in the molding of behavior is discussed.