bluuebunny/crossref_metadata_2025 huggingface dataset:
Localization of dopa decarboxylase in adult Aedes aegypti females
Authors: Schlaeger Dorothy A. , Fuchs Morton S.
Published: June 2005

Adult Aedes aegypti females contain very low levels of dopa decarboxylase activity. However, after a blood meal the activity of this enzyme rises dramatically.

Most of the dopa decarboxylase activity is lost after females are allowed to oviposit.

The bulk of the dopa decarboxylase activity observable was accounted for by direct assay of mature ovaries.

Blood feeding did not stimulate any increase of dopa decarboxylase levels in ovariectomized females.

It was concluded that after a blood meal the enzyme eventually becomes incorporated into the mature oocyte to be used for subsequent sclerotization when it is oviposited. Furthermore the presence of an intact resting ovary is necessary in order for the observed blood feeding stimulation of enzymatic activity to occur. This suggests that the follicular epithelium of the ovary may be the site of synthesis or activation of dopa decarboxylase.
Comparative study of the early embryonic cytology and nucleic acid synthesis of Ambystoma mexicanum normal and o mutant embryos
Authors: Carroll Carole R.
Published: June 2005

Maternal effect mutations are useful tools which may aid in determining how the morphogenetic organization of the egg cytoplasm controls the plan of early development. One of the most interesting of the several maternal effect genes in the axolotl, Ambystoma mexicanum, is the o gene. It is unique in that all embryos of o/o females are affected in identical fashion, uniformly stopping development during gastrulation just when the main events of organ formation should be initiated. This paper is an investigation of the cytology, karyotype, and nucleic acid synthesis in mutant and control embryos and provides some important clues as to the mechanism of action of the o+ gene. Cell division and DNA synthesis in mutant embryos are sharply reduced at the mid‐late blastula stage. At this time in normal embryos, RNA synthesis is activated but is not in embryos of o/o females. The evidence from classical hybridization experiments and experiments with enucleated embryos suggests that this RNA synthesis is necessary for gastrular morphogenesis to take place. Thus the product of the o+ gene, the o+ substance, may be a stored regulator involved in genome activation during the late blastula stage which is required for the succeeding events of gastrulation. How it is involved in regulation remains to be worked out.
Ultrastructure of early development of mouse parthenogenones
Authors: Solter Davor , Biczysko Wieslawa , Graham Chris , Pienkowski Marek , Koprowski Hilary
Published: June 2005

Mouse eggs were parthenogenetically stimulated with hyaluronidase and osmotic shock and the resulting two‐, four‐ and eight‐cell stage embryos examined with the electron microscope. The ultrastructure of parthenogenones during cleavage showed numerous differences when compared with normal development. Cortical reaction was absent and there were no microvilli on the cell surface of developing blastomeres. The cytoplasm contained numerous bundles of fibrous material, vacuoles and lipid droplets, multivesicular bodies, and agglomerates of vesicles sometimes connected with cortical granules. Cortical granules and vacuolated mitochondria were numerous and usually situated near the cell membrane. The number of free ribosomes was very small and agglomerates of ribosomes or rough endoplasmic reticulum were not observed. Nucleoli in almost all cells were so‐called primary nucleoli consisting of a dense, osmiophilic core and narrow ring of granular material. In only a few cells was reticulation of nucleoli and formation of fibrillar and granular parts noticed. Nuclear fragments and nuclei with broken membranes were present in some cells. Primary nucleoli persisted during mitosis and were in close contact with chromosomes. Cytokinesis was irregular and small and large fragments of cytoplasm surrounded by membrane were often observed between dividing cells. Our results suggested that failure of parthenogenones to develop normally is probably caused by numerous disturbances during early cleavage. Incomplete cortical reaction, persistence of primary nucleoli, a probable disturbance in RNA and protein synthesis, and irregularities during nuclear and cellular division were observed in all embryos.
Variation in dry mass and volume of nonfertilized oocytes and blastomeres of 1‐, 2‐ and 4‐celled mouse embryos
Authors: Abramczuk J. , Sawicki W.
Published: June 2005

Nonfertilized oocytes and 1‐, 2‐ and 4‐celled embryos were obtained from superovulated mice. The dry mass of cells was measured with an interference microscope either through the zona pellucida or after its removal with pronase. Volume was calculated from measurement of the diameter of the cells. From the dry mass/volume ratio the concentration of dry substance was calculated. Fertilization caused a drastic reduction in dry mass and volume from 34.6 to 31.4 ng and 189,500 to 165,000 μm3, respectively, while the concentration of dry mass of ova increased from 18.3 to 19.0 g/100 cm3. One‐celled embryos obtained 17, 23 and 34 hours after HCG gradually reduced their dry mass from 31.4 to 27.5 ng whereas their volume remained unchanged at the level of about 165,000 μm3. The increase of concentration after fertilization is followed by its reduction to about 17.0 g/100 cm3 between 17 and 23 hours after HCG and later till 34 hours remains unchanged. Mean dry mass of the blastomeres of 2‐celled embryos is one half, whereas that of blastomeres of 4‐celled embryos is one fourth of the dry mass of 34 hours 1‐celled embryos. A pronounced diversity of both dry mass and volume of the blastomeres of the embryo after second cleavage was observed.
Blood‐group‐like substances in some marine invertebrates. III. Glycoproteins with blood‐group a specificity in the cephalopods Sepia officinalis L. and Loligo vulgaris Lam
Authors: Renwrantz Lothar , Uhlenbruck Gerhard
Published: June 2005

Two cephalopods, Sepia officinalis L. and Loligo vulgaris Lam., have been investigated for soluble inhibitors of anti human blood‐group agglutinins. Only a weak inhibition was observed with respect to human anti‐A isoagglutinin. In the agar‐gel double diffusion test, however, the test substances showed a very strong precipitation reaction with heterophile anti‐A from snails. The precipitation lines were identical with that of A substance from peptone. The A‐like substances found were identified as glycoproteins containing terminal, non‐reducing bound α‐N‐acetyl‐D‐galactosamine. The biological importance of these macromolecules is discussed with particular reference to their reactive site.
A perfusion study of the effect of stanniectomy on the net influx of calcium 45 across an isolated eel gill
Authors: Fenwick James C. , So Ying Peng
Published: June 2005

The effect of stanniectomy on the net influx of calcium 45 across the gill membrane was investigated using an isolated individual gill perfusion preparation. Two weeks post‐operatively the gills from stanniectomized eels displayed a considerably higher net calcium uptake relative to the gills from mock‐operated eels. This finding supports the suggestion that the characteristic hypercalcemic response to stanniectomy is due, at least in part, to an increase in branchial calcium uptake.
Pair formation in Tetrahymena pyriformis, an inducible developmental system
Authors: Bruns Peter J. , Brussard Trudy B.
Published: June 2005

The process of pair formation by sexual strains of Tetrahymena pyriformis is an inducible pathway interrupting the cellular activities of vegetative growth. A specific series of events leading from vegetatively growing cells to mating pairs is described. The sequence is composed of two separate stages: initiation and co‐stimulation. Initiation is the response to certain starvation conditions, is sensitive to tonicity, is independent of mating types, and takes about two hours at 30°C. Co‐stimulation is a reaction between already initiated cells of different mating types, requires specific cell‐cell interactions, takes about one hour at 30°C, and results in stimulated cells which are able to form pairs. An understanding of the sequence leading to the programmed developmental activities of conjugation makes possible efficient mating techniques and facilitates a search for genetic and physiological constituents of the entire pathway.
Some characteristics of the zona pellucida antigen in the hamster
Authors: Garavagno Anita , Posada Joaquin , Barros Claudio , Shivers C. Alex
Published: June 2005

Antibody prepared in rabbits against saline extracts of hamster ovary forms a precipitate on the zona pellucida surface of oviducal eggs and immature oocytes of adult and prepubertal females. The precipitate appears in a net‐like arrangement on the outer surface only and reflects the heterogeneity of the zona. The antibody diffuses through the cumulus cells of oviducal eggs but not the cumulus cells of ovarian oocytes. Trypsin digests the inner nonprecipitated portion of the antibody treated zona but not the outer precipitated region.

An important role for the zona antigen in sperm to zona attachment and in zona penetration is indicated by: (a) the failure of sperm to attach to the zona pellucida surface following treatment of eggs with antibody; (b) the polarity of the distribution of antigen in the zona; (c) the species‐specificity of the antigen; (d) the attachment of sperm to only the outer surface of zona ghosts; (e) and the concentration of the antigen at the surface of the sperm slits in the zona.
Secretion of collagen by corneal epithelium. II. Effect of the underlying substratum on secretion and polymerization of epithelial products
Authors: Dodson James W. , Hay Elizabeth D.
Published: June 2005

Corneal epithelium isolated with EDTA from 5–11 day old chick embryos was grown on a variety of substrata in organ culture to judge the effect of the substratum on the ability of the epithelium to produce a corneal stroma. When grown on the capsule of either living or frozen‐killed lens, the corneal epithelium synthesized and secreted a proline‐rich product (as judged by autoradiography) which was shown by electron microscopy to accumulate under and within the epithelium in the form of striated collagen fibrils, many of which were 250 Å in diameter and arranged at right angles to one another as in the normal corneal stroma. Basal lamina formed, but was not continuous under the epithelium. On EDTA‐treated frozen‐killed corneal stroma, new basal lamina formation was difficult to detect because of the persistence of the old basal lamina on the stroma. When this old basal lamina was digested by trypsin, the remaining corneal stroma failed to promote new basal lamina formation by the epithelium unless the stroma contained living fibroblasts. When grown on rat tendon collagen gels, epithelia produced a proline‐rich product which seemed to polymerize in the gel instead of forming a cornea‐like stroma. Millipore filter failed to elicit any basal lamina or collagen fibril formation. The data presented in this paper are consistent with the hypothesis that juxtaepithelial extracellular matrix may provide cell surface‐stabilizing factors which promote corneal epithelial differentiation.
The neurotrophic influence on RNA precursor incorporation into polyribosomes of regenerating adult newt forelimbs
Authors: Bantle John A. , Tassava Roy A.
Published: June 2005

This study was designed to determine the effect of denervation on RNA and protein precursor incorporation into polyribosomes of nerve‐independent regenerates of the adult newt, Notophthalmus viridescens. The three stages of regeneration chosen for experimentation were the late paddle‐early digit stage (day 21), the 2–3 digit stage (day 28) and the 3–4 digit stage (day 35). Right forelimbs were denervated two days prior to polyribosome extraction while left forelimbs served as controls. To measure precursor incorporation, each newt was given either (1) H3‐uridine (six hours), (2) Na3P32O4 (90 minutes), or (3) H3‐amino acids (60 minutes). Following incorporation, regenerates were prepared for examination of either polysome profiles or polysomal RNA profiles. A technique was used which yielded undegraded, non‐membrane bound polyribosomes relatively uncontaminated by labeled cosedimenting material. It was found that denervation reduced the incorporation of RNA precursors into both ribosomal and putative messenger RNA of polyribosomes of all three stages examined. Of the three stages tested, the 35 day stage was least affected by denervation. Amino acid incorporation into polysomal nascent peptides of regenerates was also adversely affected.
Deafferentation studies on motor activity in the chick. II. Activity pattern of wings
Authors: Narayanan C. H. , Malloy R. B.
Published: June 2005

A study of the effects of deafferentation of the brachial level of the spinal cord in chick embryos was undertaken to examine the influence of afferent input on activity patterns of the wings, during embryonic, hatching and posthatching periods. Neural crest precursors of dorsal root ganglia were destroyed by superficial cauterization at somite levels 17 to 21 in embryos of stages 13–14. Between nine and 17 days of incubation no significant differences were observed in the frequency of wing movements as part of either total or local activity patterns. The prehatching and hatching behavior patterns were typical except that none of the experimental embryos managed to tuck the head under the right wing (tucking phase). Wing lifting and lowering were absent between day 18 and hatching. In hatched chicks, wings were incable of making synchronous bilateral flapping movements. The results indicate that afferent input from the wings to the spinal cord is probably involved in the patterning of wing movements. In the absence of afferent input, the chick embryos show gross disturbances in the pattern of behavior involving the wings during hatching and after hatching.
Nuclear transplantation from specialized and unspecialized gut epithelial cells of adult Xenopus laevis
Authors: McAvoy J. W. , Dixon K. E.
Published: June 2005

Two types of epithelial cells from the small intestine of adult Xenopus laevis were used as donor cells for nuclear transplantation. One type was morphologically and functionally unspecialized and mitotically active, whereas the other type was specialized and mitotically inactive. The similarity in the over all patterns of development of the two sets of transplants showed that these differences in the state of the donor cells did not affect the ability of their nuclei to support development after transplantation.
Correction of developmental abnormalities resulting from localized ultra‐violet irradiation of an amphibian egg
Authors: Malacinski George M. , Allis Charles D. , Chung Hae‐Moon
Published: June 2005

Ultra‐violet irradiation of the vegetal hemisphere of uncleaved R. pipiens eggs results in the development of characteristic defects in neural morphogenesis. These defects can be prevented from occurring if U.V. irradiated embryos are either (1) incubated at low temperature (cryoreversion), (2) microinjected with oocyte homogenate, or (3) surgically manipulated by replacing their dorsal lip with the lip of a normal (non U.V. irradiated ) embryo at the time of gastrulation.
The effects of temperature and photoperiod on antifreeze production in cold water fishes
Authors: Duman John G. , De Vries Arthur L.
Published: June 2005

A macromolecular “antifreeze” is present in the blood serum of fishes that inhabit subzero waters in winter. During the summer the “antifreeze” is not present. The effect of temperature and photoperiod on this circ‐annual cycle of “antifreeze” production was investigated. Fishes collected from subzero waters were acclimated to various temperature and photoperiod regimes. Only the combination of a long photoperiod and warm temperature resulted in the disappearance of “antifreeze” from the serum, thus providing for an efficient failsafe system. The time necessary for the complete loss of the macromolecular “antifreeze” ranged from 3 to 5 weeks. When summer fish were acclimated to various combinations of temperature and photoperiod, low temperatures resulted in the production of “antifreeze” regardless of the photo‐period. Serum Na and Cl−levels were significantly higher in cold acclimated than in warm acclimated fish. In general, fishes collected from more northerly latitudes had lower serum freezing points than the same species from warmer, more southerly waters. There seemed to be a genetic difference between populations ofAnoplarchus purpurescensfrom Amchitka, Alaska and San Simeon, California since the California fish were unable to produce “antifreeze” when acclimated to cold temperatures.
Dramatic mitotic response in planarians after feeding, and a hypothesis for the control mechanism
Authors: Baguñà Jaume
Published: June 2005

Using a new technique to stain and count planarian mitotic cells, a very rapid increase in neoblast mitotic activity has been found following feeding. The increase becomes visible 1 hour after feeding, reaches a maximum in 3–8 hours, and lasts for almost a week. These results suggest that a substantial proportion of neoblasts in the intact worm must be in the G2 phase ready to enter mitosis. The fact that the mitotic figures occur throughout the parenchyma also suggests that the stimulus may be of a neurohumoral kind.
The effect of hydrocortisone on the sheep red cell response in adult Xenopus laevis, the South African clawed toad
Authors: Ruben Laurens N. , Vaughan Margaret R.
Published: June 2005

The effect of hydrocortisone on the anti‐erythrocyte (SRBC) response of the South African clawed toad, Xenopus laevis, was studied. Hydrocortisone was administered two days prior to antigen injection and was found to reduce the eight‐day antigen‐binding response of sensitized spleen cells to 17% of its normal peak value. Control animals received injections of the vehicle solution the hormone is normally suspended in. Hemagglutination assays were also performed to ascertain whether the hydrocortisone treatment merely altered the ability of the spleen cells to bind antigen or suppressed their ability to produce antibody. Serum antibody titers were found to be depressed to 9% of the peak value by hydrocortisone treatment. Both thymus and spleen cells from the sensitized, hydrocortisone‐treated and control adult Xenopus were tested by immunocytoadherence. Unimmunized animals were also used to establish background levels. It was found that while the antigen‐binding response by immunized spleen cells was greatly decreased by hydrocortisone, thymocytes were particularly effected as their antigen‐binding capacities were reduced to background levels. It was concluded that these data support the view that the toad immune system is comparable to the mammalian with regard to hydrocortisone sensitivity of the anti‐red cell response.
Variation and its causation in earthworm regeneration
Authors: Moment Gairdner B.
Published: June 2005

The coefficient of variation for the number of segments regenerated posteriorly by earthworms (Eisenia foetida) rarely exceeds 10 but the range may be over 100% of the mean. The manner of wound healing after transection (open or enteroparietal vs. closed or cicatricial) can not be responsible for the variation since under the conditions of these experiments all worms healed in the open manner. The angle of transection can be varied widely without any measurable effect on the number of segments regenerated. However, when the cut leaves a piece of ventral body wall and nerve cord extending posteriorly, the mortality is greatly increased and the number of segments formed by the survivors greatly reduced.

Three successive regenerations in the same individuals revealed statistically highly significant consistencies indicating a genetic factor behind variation in segment number. Data from wild populations in similar but widely separated sites and also the large number of segments regenerated by individuals with initially very large numbers of segments all support the view that these worms are genetically heterogeneous regarding segment number. However, the effect of these genetic factors cannot be great.

Bilateral asymmetry in number of segments regenerated indicates that the counting mechanism underlying variation can hardly be humoral because both blood and coelomic fluid are common to both sides of the body.
Denervation‐induced changes in soluble protein content during forelimb regeneration in the adult newt, Notophthalmus viridescens
Authors: Dearlove George E. , Stocum David L.
Published: June 2005

Denervation‐induced alterations in the composition of the soluble protein population of various stages of forelimb regenerates in the adult newt were examined. Denervation alters the normal protein arrays in three ways: (1) proteins may be eliminated from an array, (2) proteins not normally present in an array may be induced to appear, and (3) proteins unique to denervated regenerates may appear in an array. The character of the denervation‐induced alteration at five days post‐amputation is basically different from that at later stages of regeneration. The stages during which the regenerate is becoming independent of the nerve for its morphogenetic activity are the ones in which the protein profiles are the most drastically altered. Morphogenetic independence of the nerve therefore does not require the synthesis of nerve‐dependent proteins, and it is concluded that nerve independence is a property generated by the production of a critical number of blastema cells. Nerve‐dependent proteins are required for the mitotic activity which leads to attainment of the critical mass, and the failure of denervated early regenerates to continue regeneration may be due solely to mitotic inhibition.
Oxygen consumptions of interscapular brown adipose tissue homogenates from two species of Peromyscus raised in different thermal environments
Authors: Mason Elliott B. , Prychodko William
Published: June 2005

The oxygen uptakes of interscapular brown adipose tissue sucrose homogenates from two species of Peromyscus that were raised in the laboratory at environmental temperatures of 5 °C, 23 °C, and 33 °C were measured by direct Warburg manometry with β‐hydroxybutyrate as substrate. Determinations were carried out at 37 °C on homogenates made from the tissues of animals remaining at the temperatures at which they were raised as well as on homogenates made from the tissues of animals that had been exposed for ninety minutes to the other temperatures of the study.

Homogenates made from the interscapular brown adipose tissues of the northern species, P. maniculatus bairdii, raised at 23 °C and 33 °C consumed comparatively small amounts of oxygen, but tissue homogenate oxygen uptakes were significantly higher when P. maniculatus bairdii raised at 23 °C and 33 °C were exposed for short periods to 5 °C. Homogenates made from the interscapular brown adipose tissues of the southern species, P. polionotus, raised at 33 °C consumed small amounts of oxygen, but tissue homogenate oxygen uptakes were significantly higher following short term exposures of P. polionotus raised at 33 °C to both 5 °C and 23 °C.

The comparatively high oxygen uptakes of homogenates made from the interscapular brown adipose tissues of both species raised at 5 °C and P. polionotus raised at 23 °C did not decrease when animals raised under these conditions were exposed for short periods to warmer environments.

The results of the study indicate a cold adaptive role for interscapular brown adipose tissue that is consistent with the events of temperature acclimation in rodents as well as the fact that species specific differences in homogenate oxygen uptakes appear to be representative of genetically based environmental adaptations.
Melanocyte developmental genetics: Biphasic control of dopa oxidase activity by the E locus of the fowl
Authors: Carver Virginia H. , Brumbaugh John A.
Published: June 2005

Aliquots of developing feather papillae isolates were measured for oxygen consumption before and after incubation in the substrate, L‐dopa. Net oxidation (dopa minus basal) indicated the amount of L‐dopa oxidized by melanocytes.

The albino‐like mutant ey/ey c/c showed minimal net oxidation when compared to its counterpart ey/ey +C/+C. This shows that the c mutation severely restricts dopa oxidase activity.

The eumelanic genotype (E/E) had high net oxidation at stage 34 which regressed to a low value by stage 38. The pheomelanic‐producing genotype (ey/ey) had a low net oxidation at stage 34 which progressed to a high value by stage 38. Dopa oxidase activity in the eumelanin and pheomelanin producing genotype (standard; +E/ +E) was biphasic. Cells from these embryos had high net oxidation at both stages 34 and 38 and a low value at stage 36. High net oxidation at stage 34 in E/E and +E/+E seem associated with eumelanogenesis, while the high net oxidation at stage 38 in +E/+E and ey/ey is thought to be related to pheomelanogenesis.

L‐dopa substrate utilization values were also completed for the heterozygote E/ey to determine if differences were detectable between this genotype and its respective homozygotes. The heterozygote net oxidation resembled E/E in pattern but at about one‐half the E/E values.

The data are discussed in terms of the E locus as a possible control gene locus which determines whether eumelanin or pheomelanin is synthesized.
The effects of epilation and hormones on the activity of rat hair follicles
Authors: Hale Patricia A. , Ebling F. J.
Published: June 2005

The growth of hair from epilated and non‐epilated areas of rats receiving a variety of hormonal treatments was investigated by pulse‐labelling with 35S‐cystine. While epilation at certain stages of the spontaneous cycle may rephase follicular activity, it did not affect the length, rate or duration of growth of the hairs which erupted subsequently, either in untreated or hormone‐treated rats.

Thyroxine shortened the active as well as the resting phase of the follicular cycle. It also increased the growth rate, so that hairs were ultimately the same length as those from untreated animals. Estradiol slightly shortened the duration of the active phase, even though the complete cycle was prolonged. It also decreased the hair growth rate. When administered simultaneously, estradiol and thyroxine exerted their effects independently.
Eye disk differentiation in the wax moth: Induction in vitro
Authors: Woolever Patricia , Pipa Rudolph L.
Published: June 2005

Ecdysterone‐induced differentiation of Galleria mellonella compound eyes in vitro is critically dependent on the age of the donor. It is greatest in explants from young prepupae, decreases with increasing donor age, and is absent in explants from 4–6 hour pupae. Failure of eye disks from pupae to differentiate in vitro seems to be the consequence of exposing them to culture conditions at a susceptible time in their development for, unlike eye disks from prepupae, they do not develop when removed from the medium and implanted into competent hosts. The explants most responsive in vitro are more liable to submerge, with resulting inhibition of development.

Three media allow differentiation of adult eye structures, and one of these is suitable without adding macromolecular compounds. Ecdysterone is essential, and will elicit ommatidia formation when it is added to the medium at concentrations ranging from 0.1–20 μg/ml. Rubrosterone is ineffective at 1.0 μ/ml of medium.

In the best‐differentiated explants each ommatidium consists of 8–10 pigmented retinal cells surrounding a rhabdom‐like core, and their axons can be traced to an enlarged optic nerve. Crystalline cones, adult cuticle in the form of facets (corneal lenses), and pigment cells also are formed.
The changes in cell shape during pigment migration in melanophores of a teleost, Oryzias latipes
Authors: Obika Masataka
Published: June 2005

The changes in cell shape of fish melanophores during pigment displacement, and the effects of colchicine and cytochalasin B on the surface morphology were studied by scanning electron microscopy. Dispersed melanophores are generally flat, with thick radiating dendritic processes. Aggregated melanophores are characterized by their swollen, hemispherical centrospheres and thin, collapsed dendrites. Colchicine induces a flattening of the entire surface of the cell while cytochalasin migration B elicits the swelling of the centrosphere accompanied by a partial migration (aggregation) of melanosomes.
Induction of nuclear breakdown and meiosis in Spisula solidissima oocytes by calcium ionophore
Authors: Schuetz Allen W.
Published: June 2005

Induction of germinal vesicle breakdown and reinitiation of the meiotic process resulted following exposure of immature Spisula solidissima oocytes to divalent ionophore A23187. Meiosis continued to completion in the presence of the ionophore; however, parthenogenetic development of the gametes did not occur. Incubation of oocytes in calcium deficient media (Ca++free or Ca++Mg++free seawater) but not Mg++ free seawater inhibited ionophore induced maturation. Effects of calcium deficiency were reversible. The results suggest that nuclear disintegration and the meiotic process induced by sperm are mediated by ionic stimuli and that the establishment of meiotic arrest is linked to the availability of calcium with in the oocyte.
Development and life cycle of the parthenogenetically activated sea urchin embryo
Authors: Brandriff B. , Hinegardner R. T. , Steinhardt R.
Published: June 2005

A method is reported for inducing parthenogenetic development in eggs of the sea urchinLytechinus pictus, a species which previously could not be artificially activated. NH4OH or the calcium ionophore A23187 are used as activating agents followed by hypertonic treatment. The ionophore is superior in activating large numbers of unfertilized eggs, whereas NH4OH produces a larger percent of embryos able to undergo gastrulation. Both feeding larvae and urchins arising from these artificially activated eggs are diploid. All individuals in which sex has been identified have been female. The viability of these completely homozygous organisms is low compared to their fertilized counterparts.
Ontogenetic expression of larval and adult hemoglobin phenotypes in the intergeneric salmonid hybrids
Authors: Iuchi Ichiro , Suzuki Ryo , Yamagami Kenjiro
Published: June 2005

Ontogeny of the hemoglobins of Honmasu (Oncorhynchus rhodurus, HXH), brook trout (Salvelinus fontinalis, BXB) and their reciprocal hybrids (HXB and BXH) was examined electrophoretically as well as spectrophotometrically. All of these fish have electrophoretically distinct larval and adult type hemoglobins and the transition from one type to the other occurred early during post‐hatching development.

In the case of larval hemoglobins, the electrophoretic pattern of a hybrid, BXH, resembled that of the maternal parent, brook trout (BXB), while the hemoglobin of the reciprocal hybrid, HXB, differed markedly from that of the maternal parent, Honmasu (HXH), in that it possesses a diffuse pattern. Spectrophotometric examinations indicated that this was mostly methemoglobin.

Adult type hemoglobins at more advanced stages of both hybrids were electrophoretically resolved into the parental hemoglobins. However, no “hybrid” hemoglobins were detected.

Because there was abnormal hemoglobin formation in the larval erythrocytes (erythrocytes L) of the HXB hybrid, and then normal hemoglobin synthesis in the adult erythrocytes (erythrocytes A) of the same fish at later developmental stages, it appears that the paternal effects upon the hemoglobin differed in these two erythroid cell lines of the developing trout.
DNA synthesis during lens regeneration in larval Xenopus laevis
Authors: Waggoner Phillip R. , Reyer Randall W.
Published: June 2005

Larvae of Xenopus laevis at stages 50–53 were lentectomized and then injected with tritiated thymidine at various times after lentectomy. In Series I, the animals were injected 1, 2, 3, 4, 6, 8, 10, 12, 15, or 17 days after lens removal and fixed three hours after injection. Autoradiographs of serial cross sections through the eyes were prepared. Increased incorporation of thymidine in the cells of the regenerating lens was first observed two days (stage 2) after lentectomy. All of the cells of the lens vesicle incorporated H3‐thymidine until stage 4 at which time the cells in the inner wall of the vesicle began to differentiate into lens fibers. Labelling then became restricted to the peripheral cells (prospective lens epithelium and prospective lens fibers). At stage 5 of regeneration, only cells of the lens epithelium incorporated H3‐thymidine. In Series II, animals injected three or four days after lentectomy were fixed daily from one to seven days after injection. Many stage 3 and stage 4 regenerates were recovered with label throughout and stage 5 regenerates were found, seven days after injection, with label over the lens fibers as well as over the lens epithelium.
Composition of fluid from the notochordal canal of the coelacanth,Latimeria chalumnae
Authors: Griffith Robert W. , Mathews Martin B. , Umminger Bruce L. , Grant Blake F. , Pang Peter K. T. , Thomson Keith S. , Pickford Grace E.
Published: June 2005

Fluid from the notochordal canal of the coelacanth,Latimeria chalumnae, was analyzed for major inorganic and organic constituents and compared with blood serum from the same fish. Significantly or suggestively lower levels of sodium, magnesium, calcium, bicarbonate, sulfate, total carbohydrates, glucose, lactate, cholesterol, bound phosphate and total proteins were found in notochordal fluid than in serum, whereas potassium, chloride, urea, trimethylamine oxide, and total free amino acids were higher and inorganic phosphorus essentially identical. Osmolarity of notochordal fluid (1058 mOsm) exceeds that of serum (942 mOsm). A whitish precipitate in the fluid consisted of a matrix of fibers 100 Å in diameter and of indefinite length. It resembled a sialoglycoprotein in composition and was stabilized by disulfide bonds. The fluid contained cellular debris.
Influence of antigen dose on antibody production of intact and splenectomised Xenopus laevis
Authors: Collie Madeleine H. , Turner Rodney J.
Published: June 2005

Antigen persistence and serum antibody production in intact Xenopus were monitored using human gamma globulin (HGG), in adjuvant, in various immunisation schedules. Retention of HGG in spleen and serum was directly related to the quantity injected. However, antibody responses to a dose range between 1 μg‐6 mg antigen were similar in intensity. These were detected in the serum two weeks after injection and at this stage were exclusively mercapto‐ethanol (ME) sensitive; ME‐resistant antibodies had appeared by four weeks. No antibodies were detected below a dose of 100 ng HGG.

The effect of splenectomy on antibody levels was tested using HGG/adjuvant or sheep erythrocytes (SRBC) in saline. Splenectomised toads showed impairment of antibody responses only to threshold doses of HGG (100 ng) but to a wider range of SRBC doses.
Fine structure of the zona pellucida of unfertilized egg cells and embryos
Authors: Barańska Wanda , Konwiński Marian , Kujawa Marek
Published: June 2005

The fine structure of the zona pellucida of mouse unfertilized egg cells and of mouse embryos was investigated. In addition to standard fixation for electron microscopy, fixation with an addition of ruthenium red was used and found to be especially valuable for the purpose of studying the zona pellucida.

The zona pellucida of unfertilized egg cells and of embryos consisted mainly of fibrillar and granular material. There were two layers: a thicker internal and a denser external layer in the zona pellucida of the unfertilized egg cells. The zona pellucida of embryos had, in addition to these two layers, a coarsegrained intimal layer inside the internal layer and a fine‐grained peripheral layer outside the external layer. The intimal layer seems to be the product of cortical reaction whereas the peripheral layer can be accumulated and modified during the passage of the embryo through the female genital tract. The influence of developmental events and environmental factors on the fine structure of zona pellucida was discussed.
Cellular basis for the production and secretion of the hatching enzyme by frog embryos
Authors: Yoshizaki Norio , Katagiri Chiaki
Published: June 2005

Stage 17, 19, and 21 embryos of the grass frog, Rana chensinensis, were deprived of their envelopes, cultured for 36 hours, and the proteolytic activity of the culture media was determined. The activity is low during stages 17–19, increases sharply during stages 19–21, and remains at a high level during stages 21, 22. Comparison of the media in which the embryonic halves were cultured revealed that the secretion of the enzyme is dependent on the anterior part of the embryo. Embryonic extracts showed no significant activity at any stages examined. Culture of the epidermal explants from different embryonic regions proved further that the enzyme secretion is restricted in the dorsal frontal portion where a particular type of cells is predominant.

In the tailbud embryo, large, flask‐shaped epidermal cells, designated as the hatching gland cells (HGCs), are mostly distributed in the dorsal frontal region, and in small number along the dorsal mid‐line. Electron microscopically, the HGC is characterized by prominent microvilli at the apical cell surface, a number of apically localized, membrane‐limited secretory granules, well‐developed Golgi complexes, as well as an abundance of rough‐surfaced endoplasmic reticula. The differentiation of HGC is first discernible at stage 17, and the cell acquires its histotypic characteristics at stage 18. The cell continues to synthesize and secrete granules during stages 18–21 and undergoes gradual regression after the hatching stage, accompanied by the formation of an elaborate phagolysosome within the cell.

The evidence presented strongly indicates that HGC is a specific epidermal cell adapted for synthesizing and secreting the hatching enzyme in the prehatched frog embryos.
Elimination of 137Cs and 59Fe and its relationship to metabolic rates of wild small rodents
Authors: Baker Charles E. , Dunaway Paul B.
Published: June 2005

Elimination of 137Cs and 59Fe by three species of wild rodents was measured in laboratory and field experiments to determine whether excretion rates of these nuclides are influenced directly by general metabolic (CO2 production) rates. Sigmodon hispidus and Peromyscus leucopus were used in both field and laboratory experiments, and Reithrodontomys humulis was investigated only in the laboratory.

Final‐component biological half‐lives (Tb) of 59Fe for Sigmodon averaged 108 days in winter, 144 days in spring, and means ranged from 176 to 242 days under various laboratory conditions (ambient temperature, cold‐exposure, irradiation, and chemical metabolic inhibition); for Peromyscus, values were 50 days in winter, 47 days in spring, and 289 days (at ambient temperature only) in the laboratory; for Reithrodontomys mean values ranged from 121 to 178 days at different laboratory treatment levels.

Biological half‐lives of final‐component 137Cs elimination for Sigmodon averaged 7.5 days in winter, 7.9 days in spring, and means ranged from 7.7 to 8.6 days at the different treatment levels in the laboratory. Laboratory mean values for Reithrodontomys ranged from 3.5 to 3.9 days. For Peromyscus, Tb values averaged 3.4 days in winter, 3.6 days in spring, and 3.5 days in the laboratory.

The data suggested that elimination of 59Fe is influenced by metabolic rates of rodents in the field, but laboratory experiments were unable to demonstrate any predictable relationship. Neither did the rate of final‐component 137Cs loss from rodents appear to be influenced by metabolic rate in the laboratory or in the field.

However, final‐component Y‐axis intercept values of 137Cs exhibited a linear correlation with metabolic rates, and equations were derived from these intercept values to predict metabolism in the field for two species: for Sigmodon, Daily Average CO2 Production (ml/hr/g, STP) [5.24–0.9172 (logea)] [0.886]; and for Reithrodontomys, = [12.51–1.80 (logea)] [0.886].
Effect of UV on cleavage of Xenopus laevis
Authors: Beal Clayton M. , Dixon K. E.
Published: June 2005

UV irradiation of the vegetal pole of stage 2 X. laevis embryos with doses of 6000–18000 ergs/mm2 delayed or inhibited cytokinesis in the vegetal hemisphere. Nuclear division continued so that a syncytium was formed, the size and persistence of which depended on the dose. Embryos which received a low UV dose were subsequently able to recover whereas embryos receiving a high dose were unable to gastrulate successfully. The implications for investigations into the role of cytoplasmic determinants are discussed.
Effects of parathyroidectomy on calcium and sodium concentrations of serum and coelomic fluid in bullfrog tadpoles
Authors: Sasyama Yuichi , Oguro Chitaru
Published: June 2005

Parathyroidectomy of larval and metamorphosing tadpoles of Rana catesbeiana caused significant decrease in Ca concentrations in serum and coelomic fluid, although their Na levels did not show significant changes. These results suggest that the parathyroid gland of the tadpole plays an important role in the elevation of Ca level in larval stages as well as in adults.
Non‐glial phagocytes within the degenerating optic nerve of the newt (Triturus viridescens)
Authors: Turner James E.
Published: June 2005

Two non‐glial phagocytes were found to participate along with ependymoglial cells in Wallerian degeneration of the severed optic nerve of the newt (Triturus viridescens). The first type of non‐glial cell (a polymorphonuclear phagocyte) was positively identified as a neutrophil and participates in the early stages of degeneration. Cells of this type make a brief appearance, reaching a peak by the second postoperative day (2 p.o.d.), and quickly diminish until few can be found by 4 p.o.d. Neutrophils invade the degenerating optic nerve from surrounding connective tissue spaces, most likely, through channels which penetrate the nerve parenchyma.

The second type of non‐glial cell is an invading mononuclear phagocyte which exhibits characteristics of microglial cells reported in other vertebrate species. Such cells appear in the nerve much later than the neutrophils and towards the end of Wallerian degeneration (6–10 p.o.d.). Their mode of entry and exit appears to be the same as that reported for neutrophils.

The neutrophils and microglial‐like, mononuclear phagocytes may serve to supplement the histolytic action of the ependymoglial cells, picking up scattered fragments of degenerating myelin and axons.
Absence of maternal proteins in 5–7‐day blastocyst fluid indicates limited protein passage before implantation
Authors: Kulangara Abraham C.
Published: June 2005

Rabbit serum albumin (RSA) and gamma globulin (RGG) were measured in fluid collected from single 5, 5.5, 6 and 6.5‐day blastocysts of New Zealand White rabbits, using a radial immunodiffusion method capable of detecting a minimum of 2–5 μg/ml in 1 μl. The samples showed little or no RSA and RGG. Three sources of contamination in fluid collection were identified. They are, blastocyst contact with aqueous solutions used to flush them out or rinse them, carrying in of surface proteins by pipette tips and withdrawal of trophoblast from lemmas. It is shown that fluid collected without precautions to avoid contamination will contain uterine fluid constituents.

Bovine serum albumin (BSA), RSA and RGG pass readily into blastocyst fluid in vitro and after intrauterine injection. However, such passage is abnormal because BSA does not appear in 5–7‐day blastocyst fluid after intravenous injection of the mother (Kulangara and Crutchfield, '73) and normal 5–7‐day fluid shows little or no RSA and RGG. High viscosity and pH in the normal uterine lumen greatly reduce protein passage so that only traces reach trophoblast cells, which seem to digest this protein with lysosomal enzymes and/or transport it outward, thereby maintaining a virtually protein‐free blastocyst fluid, prior to implantation. Restriction of protein passage appears to be essential, since normal development is interrupted by intrauterine injections.
Phenogenetics of a suppressor and an enhancer gene of the lozenge34k allele of Drosophila melanogaster
Authors: Beeson Virginia S. , Bender Harvey A.
Published: June 2005

The recessive sex‐linked gene, lozenge34k was initially identified on the basis of its effect on the compound eye of Drosophila melanogaster. However, its pleiotropic effects include modification of the antennae, legs and female reproductive structures as well. Two modifier genes, a third chromosome suppressor, su(lz34k), and a fourth chromosome enhancer, spae(lz), have been previously described and their effects on the various mutant characters of the lozenge34k phenotype were the basis of this study. These investigations included scanning electron microscope observations of the external morphology of the compound eye, a quantitative determination of the effects of the mutant genes on the tarsal claws, antennae and female reproductive capacity, and an examination of the functional ability of the compound eye. It was found that the modifier genes had little effect on the aspects of the lozenge34k phenotype other than the compound eye. The enhancer seems to suppress the lozenge phenotype with regard to the length of the antenna but otherwise there is no effect of the modifiers with regard to antennae, tarsal claws, spermathecae or female reproductive capacity (the number of eggs oviposited or the number of adult progeny ensuing from females tested). The lozenge‐enhanced males also differed significantly from the other types in being less successful at inseminating females in the light. The lozenge and lozenge‐suppressed males were more successful than the lozenge‐enhanced but less so than the wild type. This can be related to their ability to “see” since in the dark all types were at an equal disadvantage. Wild flies exhibited a positive phototactic response, lozenge were significantly less responsive, and both the suppressed and enhanced flies were even less so. Compound‐X females lacking the lozenge34k allele were tested for phototaxis. Those homozygous for the suppressor were significantly less phototactic than the others indicating that the suppressor alone has a phenotype at this level. Except for the phototactic response of lozenge‐suppressed flies, the functional ability of the compound eye can be correlated with its morphology.
Acetylcholinesterase in singly and multiply innervated muscles of normal and dystrophic chickens. II. Effects of denervation
Authors: Linkhart T. A. , Wilson B. W.
Published: June 2005

Neural regulation of mature normal fast twitch muscle of the chicken suppresses high activity, extrajunctional localization, and isozyme forms of acetylcholinesterase (AChE) characteristic of embryonic, denervated and dystrophic muscle. Normal adult slow tonic muscle of the chicken retains intermediate levels of activity and embryonic isozyme forms but not extrajunctional activity; it is not affected by muscular dystrophy. The hypothesis that neural regulation of the AChE system is lacking in slow tonic muscle and thus not affected by dystrophy was tested by denervating the fast twitch posterior latissimus dorsi and slow tonic anterior latissimus dorsi muscles of normal and dystrophic chickens. Extrajunctional AChE activity and embryonic isozyme forms increased, then declined, in both muscles. The results suggest that control of AChE is qualitatively similar in slow tonic and fast twitch muscle of the chicken.