bluuebunny/crossref_metadata_2025 huggingface dataset:
In vitro uptake and incorporation of amino acids by blastocysts from intact and ovariectomized mice
Authors: Weitlauf Harry M.
Published: June 2005

Blastocysts were recovered from the uteri of intact or ovariectomized mice and incubated with a mixture of 14C amino acids in vitro. The level of uptake and incorporation of the amino acids as estimated by scintillation counting was higher in blastocysts from intact than in those from ovariectomized animals. Furthermore, when the two types of eggs were “pre‐incubated” for varying periods in non‐radioactive medium and then placed in 14C amino acids, the level of incorporation by blastocysts from intact animals remained constant while that in blastocysts from ovariectomized animals increased with time. The increasing ability to take up and incorporate amino acids in vitro by blastocysts recovered from the uteri of ovariectomized animals suggest that in the absence of ovarian hormones, the uterus exerts a negative influence on the metabolism of the blastocysts. In addition, incubation of the blastocysts with estradiol 17β and/or progesterone did not affect the uptake or incorporation of amino acids suggesting that the hormones do not influence protein synthesis in the eggs by direct action.
In vitro evidence of steroidogenesis in the amphibian (Rana pipiens) ovarian follicle and its relationship to meiotic maturation and ovulation
Authors: Snyder Ben W. , Schuetz A. W.
Published: June 2005

Cyanoketone (CK) was used to investigate the involvement of steroidogenesis on gonadotropic hormone‐induced oocyte germinal vesicle breakdown and ovulation in frog ovarian follicles in vitro. Cyanoketone inhibited pituitary hormone‐induced oocyte meiotic maturation and ovulation but had no inhibitory effects on progesterone‐induced germinal vesicle breakdown. In contrast, CK inhibited meiotic maturation induced by low but not high doses of pregnenolone. The effect of CK on the uptake and metabolic conversion of 3H‐pregnenolone by ovarian follicles was also studied. Ovarian follicles removed 3H‐pregnenolone from the incubation medium and frog pituitary homogenate stimulated the net uptake of this steroid by nearly 60%. Cyanoketone had no effect on this uptake. Thin layer chromatographic analysis of extracts of ovarian follicles previously incubated in 3H‐pregnenolone, indicated that radioactive progesterone as well as other products were synthesized in the presence or absence of pituitary hormones. Cyanoketone inhibited the amount of 3H‐pregnenolone converted by the follicles and similarly reduced the formation of steroid corresponding chromato‐graphically to 3H‐progesterone. These results indicate that metabolism of pregnenolone occurs in the amphibian follicle and that CK interferes with this process presumably as a result of the inhibition of 3β‐hydroxysteroid dehydro‐genase. These data further suggest that this enzyme is an important link in gonadotropic initiation of meiotic maturation and ovulation in amphibian ovarian follicles.
Postembryonic development in the antenna of the cockroach, Leucophaea maderae: Growth, regeneration, and the development of the adult pattern of sense organs
Authors: Schafer Rollie
Published: June 2005

Growth in the antenna of the cockroach, Leucophaea maderae, is achieved through the addition of new segments by the division of the third antennal segment (the meriston) and several segments immediately distal to it. The scape, pedicel, and meriston are all capable of regenerating lost segments. Proximal ablations of the antenna often drive the animal into one or two extra instars. The antennifer region of the head will also regenerate a new antenna after its total amputation, but the insect passes through at least one additional instar before new segments appear. The total number of antennal sensilla increases by a factor of nine times during postembryonic development. Most of the increase is due to the proliferation of olfactory sensilla. Nearly 40% of the total postembryonic increase in sensilla comes at the terminal molt, subsequent to a similarly large increase in antennal surface area in the previous nymphal instar. This finding supports the theory that surface area effects are vital in the differentiation of cuticular sensilla. Evidence from regeneration experiments suggests that the juvenile hormone may also inhibit the differentiation of new olfactory sensilla during the nymphal stages.
The development of eggs produced by the female‐sterile mutant almondex of Drosophila melanogaster
Authors: Shannon Mary P.
Published: June 2005

The embryological development of the eggs laid by the sex‐linked recessive female‐sterile mutant almondex (amx) of Drosophila melanogaster has been analyzed by use of both living and sectioned material.

The mating amx ♀ × amx ♂ is lethal to all embryos. Advanced but abnormal development occurs. Development is normal until shortly after the time of maximal germ band extension. The principal anomalies involve derivatives of the ectoderm and somatic mesoderm; both dorsal closure and head involution are impaired.

The mating amx ♀ × non‐amx (+) ♂ produces a similar pattern of damage in male (amx/Y) embryos, none of which hatch. In female (amx/+) embryos, however, there is an amelioration of development, although the pattern of damage is still so severe that most embryos succumb. A few female offspring and occasional non‐disjunctional non‐mutant (XO) male offspring survive to the adult stage; these adult progeny frequently have defects of the thorax and abdominal sternites.

These results can be explained by assuming that the cytoplasm of eggs produced by amx females is deficient for some material that is necessary for normal development. It is suggested that either an inherent structural defect in the presumptive ectoderm or some metabolic defect to which the ectoderm is particularly susceptible may underlie the morphological defects found in the progeny from amx females.
An analysis of urodelian retinal regeneration: I. Studies of the cellular source of retinal regeneration in Notophthalmus viridescens utilizing 3H‐thymidine and colchicine
Authors: Keefe J. Richard
Published: June 2005

The process of retinal degeneration and regeneration in retinectomized or enucleated and reimplanted eyes of adult Notophthalmus viridescens has been studied following staged administrations of tritiated thymidine or colchicine. In control left eyes, no labeled cells were observed in either the retina, pigment epithelium, or ora serrata. In retinectomized or enucleated eyes, retinal degeneration proceeded from the posterior central pole circumferentially to the ora serrata, with complete retinal degeneration being consistently observed. Retinal replacement originated from two cellular sources: the posterior pigment epithelium and the anterior complex, consisting of cells in the ora serrata and pars ciliaris retina.

The posterior pigment epithelium gave rise to an initial central retinal portion which differentiated in an annular pattern which extended from the optic nerve to the vortex veins. Cellular addition from the pigment epithelium became restricted to these two regions by day 25. The anterior retinal mass was regenerated from the anterior elements (ora serrata/pars ciliaris retina) with a minor contribution from the underlying anterior pigment epithelium. Data concerning the relative numbers of cellular types involved in the regenerative sequence and the times of their function are presented. Peak labeling occurred in the posterior pigment epithelium at day 20, the pars ciliaris retina at days 18 and 40, and the new retina at days 28 and 41. By 30 days regional sites of cellular proliferation became established that coincided with the pattern of ocular blood vessels. Retinal differentiation followed the pattern commonly observed during retinal development.

The significance of these observations with respect to earlier work demonstrating a different sequence for retinal restoration is discussed.
An analysis of urodelian retinal regeneration: II. Ultrastructural features of retinal regeneration in Notophthalmus viridescens
Authors: Keefe J. Richard
Published: June 2005

The process of retinal regeneration in the posterior pole of enucleated and reimplanted eyes of adult Notophthalmus viridescens was studied with the electron microscope. The posterior pigment epithelium displayed two distinct cellular types which served either as phagocytic cells or for repopulating the retina. The phagocytic cells, which displayed a marginal nuclear chromatin, numerous mitochondria and profiles of rough endoplasmic reticulum, served to remove degenerating retinal and lens debris. The cells destined to repopulate the retina appeared to pass through an indifferent phase in which both single melanin granules and sequestered areas of pigmented cytoplasm were extruded. These cells displayed a markedly heterochromatic nucleus surrounded by a cytoplasm with scattered free ribosomes, short profiles of endoplasmic reticulum, and small rounded mitochondria. Once the retinal regenerate has been formed, the pigment epithelium was restored upon Bruch's membrane and the cells displayed melanin formation and an extensive smooth endoplasmic reticulum. The development of the full melanin complement, with apical cytoplasmic fringes and rough endoplasmic reticulum, depended upon differentiation of the new retina.

By day 25, the newly reconstituted retina began to display vertical alignment of cells and differentiation of the inner layers. Each of the photoreceptors passed through an indifferent phase in which all cells showed a similar mitochondrial ellipsoid and small glycogen paraboloid. Rods, due to their increase in size, and double cones, due to the encapsulation of the principal element within the accessory element, were the first photoreceptors to become recognizable. The initial formation of the outer plexiform layer resulted from an outgrowth of horizontal cell processes coincident with a wave of local cellular degeneration. Synaptic bases of the photoreceptors developed fully after invagination by the principal bipolar and horizontal processes.

The significance of the cellular patterns observed during retinal restitution and differentiation, with respect to the origin of the double cone and the formation of rods and cones, and the nature of the pigment epithelial cells and their response to local degeneration of the retina, is discussed.
Effects of temperature on the ultrastructure of severed crayfish motor axons
Authors: Nordlander Ruth H. , Singer Marcus
Published: June 2005

Nerves containing opener and closer motor axons in the right claws of crayfish were severed and the animals maintained in three groups at 16, 22 or 28°C. After selected intervals ranging from 5 to 80 days the nerves were prepared for electron microscopy and examined 1.5 to 2 cm distal to the cut. The findings of our earlier study (Nordlander and Singer, '72) that motor axons of animals kept at 16°C showed no morphological evidence of degeneration was confirmed. At the elevated temperatures, however, 30% of the animals showed motor axon degeneration. There was no significant difference in the occurrence of degeneration between the 22 and 28° groups. In early stages degenerating axons were characterized by a central core of amorphous material in which some microtubules were embedded, a surrounding area with mitochondria and assorted vesicles, and often an interrupted or totally lacking axolemma. By two weeks after cutting the axons had completely degenerated. In some animals the axonal sheath later degenerated but in others it persisted for up to eight weeks. Motor axons which failed to degenerate at the higher temperatures showed reactive changes like those occurring at 16°C except that the changes progressed more rapidly; the glial wrappings were loosely arranged; glial cytoplasm swelled with organelles including mitochondria, endoplasmic reticulum and Golgi elements; and in advanced stages, regenerating axons appeared within the glial wrappings.
Relations of prolactin and thyroid hormone to molting, skin texture, and cutaneous secretion in the red‐spotted newt
Authors: Dent J. N. , Eng Ludeman A. , Forbes M. S.
Published: June 2005

The effects of prolactin on skin texture, on cutaneous secretion and on molting have been examined in the red‐spotted newt under several hormonal conditions. In the adult newt skin is smooth and is covered with varying amounts of cutaneous secretion. Under laboratory conditions the skin ordinarily becomes rough and tuberculated within one or two weeks. Doses of 1.2–120 units of prolactin caused the skin of intact, laboratory‐conditioned, red‐spotted newts to become smooth and slimy. Similar changes were seen in newts bearing pituitary autografts which are presumed to secrete excessive amounts of prolactin or prolactin‐like hormone. No change in skin texture or secretion was detected in hypophysectomized newts treated with prolactin. It has been reported recently that 120 units of prolactin induces molting in the hypophysectomized European crested newt (Vellano et al., ';70). Although 3 of 15 hypophysectomized red‐spotted newts molted in response to that dose of prolactin, TSH in amounts equivalent to that which may have contaminated the prolactin produced similar results. Thyroidectomized newts showed no cutaneous response to 120 units of prolactin. Thyroidectomized newts kept in water to which 10 μgm/liter of 1‐thyroxine had been added molted only rarely, but when thyroidectomized animals were put into 10 μgm/liter of 1‐thyroxine and injected with 12 units of prolactin they began to molt normally and their skins became smooth and slimy. It is concluded that in the red‐spotted newt prolactin alone does not induce molting but may facilitate molting, probably through the stimulation of cutaneous secretion, when introduced with thyroid hormone. It is further concluded that although prolactin induces changes in skin texture and in cutaneous secretion, those responses are to some extent mediated by the thyroid hormone.
Ecology and behavior of Anthias squamipinnis (peters, 1855) (Anthiidae, Teleostei) in the coral habitat of eilat (Red Sea)
Authors: Popper Dan , Fishelson Lev
Published: June 2005

Anthias squamipinnis (Anthiidae, Teleostei), a sexually dimorphic coral fish, is found in large swarms along the western coast of the Gulf of Aqaba. Each swarm is permanently bound to a particular rock or coral head. During daytime, the fish stay close to their coral head and spend the night in holes and crevices in the rock.

Some of the males are territorial, defending water spaces near the rock, performing special displays and chasing away male intruders. The nonterritorial males swim in separate swarms closer to the bottom. A third part of the population consists of females and young that swim above the swarm of nonterritorial males. These last two groups form the main mass of the population and are spread out rheotactically in front of the rock, feeding on the plankton carried by the current.

Spawning is carried out in the evening from November to June. It is preceded by a precopulatory “dance” initiated by the territorial males and joined by the females and nonterritorial males. The eggs are planktonic.

Sexual inversion was observed in many specimens in nature and in captivity. After a period of about one year, functional females gradually change coloration and switch into functional males. They may join either the swarm of nonterritorial males or the group of territorial males.
Nucleotide phosphatase in Strongylocentrotus purpuratus eggs. I. Localization
Authors: Schmidt Waldemar A.
Published: June 2005

The demonstration of nucleotide phosphatase activity in mature S. purpuratus eggs is reproducible with the methods used. A Mg + + sensitive activity is demonstrated with ATP as substrate. This activity is present throughout the medulloplasm and only occasionally in the cortex. The activity is lost from eggs stored for more than five days after fixation. In whole mounts of mature eggs, the activity in the medulloplasm suggests many possible subcellular localizations. Localization of the activity to subcellular structures in the medulloplasm was accomplished by density‐gradient centrifugation of the mature eggs. By this method nucleotide phosphatase activity was present in the fractions containing yolk granules and endoplasmic reticulum and was not associated with the lipid droplets, nuclei, Golgi complexes, atypical tubular endoplasmic reticulum, heavy bodies, annulate lamellae, or mitochondria.
Correlated physiological and ultrastructural studies on specialized muscles. IIIa. Neuromuscular physiology of the power‐stroke muscle of the swimming leg of Portunus sanguinolentus
Authors: Hoyle G. , Burrows M.
Published: June 2005

The power stroke for swimming in Portunid crabs is provided by the basi‐ischiopodite levator muscle of the fifth leg. This was studied in Hawaiian specimens of Portunus sanguinolentus and found to consist of three distinct portions comprising differently‐colored muscle fibers: white, light pink and deep pink. The innervation, membrane properties and the behavioral role of these fibers in swimming have been examined. Each portion is separately innervated. Fibers of the white portion have propagated action potentials producing rapid twitch contractions. They are used only in fast swimming or in escape responses. Membrane responsiveness of the deep pink fibers ranges from complete electrical inexcitability to moderate graded electrogenesis, whilst their contractions are slow and are probably used to maintain limb posture or in slow swimming. Fibers of the light pink portion range from ones capable of propagated action potentials and rapid twitches to others which produce graded responses only and slower contractions. The light pink portion provides the main thrust for swimming: during slow swimming only two axons are active but as the speed increases further units are recruited so that during escape responses all four axons innervating this portion are active.
Correlated physiological and ultrastructural studies on specialized muscles. IIIb. Fine structure of the power‐stroke muscle of the swimming leg of Portunus sanguinolentus
Authors: Hoyle Graham
Published: June 2005

The fine structures of muscle fibers of the white, light pink and deep pink portions of the power‐stroke muscle of the swimming leg of Portunus sanguinolentus are described. Although the parts are very different functionally, there are only slight differences in the sarcomere lengths of component fibers. The sub‐structures of thick filaments, Z lines, double M lines and sarco plasmic reticulum are also similar. The principal differences between them lies in different numbers of mitochondria which are very numerous in the deep pink fibers, occupying up to half the fiber volume, fairly numerous in light pink fibers, but sparse in white fibers. The mitochondria are responsible for the color differences. Neuromuscular junctions in deep pink fibers lie deeply embedded, close to the contractile material. A slow relaxation rate of pink fibers appears to be related to the presence of the mitochondria.
The peripheral dependency of Rohon‐Beard cells
Authors: Bacher Beatrice E.
Published: June 2005

Sensory Rohon‐Beard cells of Rana pipiens embryos were examined for dependency on the peripheral innervation. Flank ectoderm was surgically removed, the area being maintained skinless by lateral parabiosis. The Rohon‐Beard cells in each side of the spinal cord were counted at a later developmental stage; the number was always less on the side with the reduced skin area. Intact animals, operated controls, and tails of the parabiotic pairs did not show such a bias in cell distribution. Deprivation of the neurotrophic periphery is postulated as the cause of the premature disappearance of the Rohon‐Beard cells; it is further suggested that the disappearance of these cells during normal development might be effected through the peripheral innervation.
Effect of pinealectomy and photoperiod on oviposition and gonadal development in the fish, Oryzias latipes
Authors: Urasaki Hiroshi
Published: June 2005

Intact females of Oryzias latipes exposed to 14 hours of light per day for 40 days continued to lay eggs for as long as 35 days. Under a similar photoperiod, pinealectomy shortened the period of oviposition to four days and enucleation to seven days. Moreover, the mean gonosomatic indices (GSI: the gonadal weight expressed as a percentage of the body weight) of intact, pineal‐ectomized, and blinded female fish under the same photoperiod were 10.56 ± 0.53, 3.77 ± 0.31, and 6.31 ± 0.48, respectively. Fish receiving eight hours of light per day laid eggs for only two to seven days, whether they were intact or operated. The GSI's were slightly larger in both pinealectomized and enucleated females than in intact ones (P < 0.1).

The significant difference in GSI between blinded females subjected to the eight‐hour photoperiod (3.45 ± 0.48) suggests the presence of an extraocular photoreceptive organ mediating the effects of light on the gonad.

The shortening of the period of oviposition in pinealectomized fish seems to show the involvement of the pineal in gonadal development and oviposition; probably the pineal functions as the photoreceptor.
Lipids of the fertilized egg and adult brain of Fundulus heteroclitus
Authors: Bailey Claudia F.
Published: June 2005

Column chromatography of lipid extracts from the fertilized egg and adult brain of Fundulus heteroclitus separated three major fractions: neutral lipid, glycolipid and phospholipid. The neutral lipid fraction of the egg, approximately 61% of the total, consisted primarily of triglyceride. Cholesterol was present in significant amounts, along with smaller quantities of cholesterol esters and hydrocarbons, and a diverse group of fatty acids were released upon saponification. The neutral lipid fraction from brain, about 30% of the total lipid, exhibited less variety in fatty acid composition and consisted primarily of cholesterol.

Phospholipids accounted for 37% of the egg total lipid and 60% of the brain total lipid. Thin‐layer chromatography revealed phosphatidyl choline and phosphatidyl ethanolamine as the major components of the egg phospholipid fraction. Brain phospholipids included phosphatidyl choline, phosphatidyl ethanolamine and many additional components. Phosphatidyl choline accounted for approximately 55% of the phospholipid in both egg and brain samples.

Fundulus eggs contain all lipid components previously identified in yolky vertebrate eggs. The presence of glycolipids, cholesterol esters, hydrocarbons and the tendency toward unsaturation in fatty acids of the neutral lipids in fish eggs has been demonstrated.

The lipid composition of Fundulus brain conforms to that of the usual vertebrate brain, with its low triglyceride, high cholesterol and high phospholipid content. In contrast to avian and mammalian brain, however, in Fundulus brain phosphatidyl choline rather than phosphatidyl ethanolamine is the major phospholipid and the amount of glycolipid is small.
Persistence of maternal RNA in Engystomops embryos
Authors: Hough Barbara R. , Yancey Paul H. , Davidson Eric H.
Published: June 2005

Females of the neotropic anuran Engystomops pustulosus were injected with 3H‐uridine and produced eggs containing RNA labeled during synchronous oogenesis. The >4S, labeled RNA extracted from these eggs, and from embryos which developed from them, was hybridized with an isolated repetitive fraction of Engystomops DNA, and the hybrids were assayed on hydroxyapatite columns. About 1% of the egg RNA is transcribed from DNA sequences included in this fraction. Hybridization of labeled ribosomal RNA was minimized by the addition of excess unlabeled ribosomal RNA extracted from Xenopus ovaries. The labeled RNA of embryos up to the tadpole stage was identified as maternal transcript by competition experiments with unlabeled Engystomops oocyte RNA. It was found that maternally‐labeled RNA is retained in embryos at least up to the tadpole stage.
The respiratory physiology of hemocyanin in Limulus polyphemus
Authors: Falkowski Paul
Published: June 2005

Data obtained from measurements of internal pO2's with oxygen micro‐electrodes and measurements of oxygenation are used to interpret the respiratory function of Limulus hemocyanin.

In animals acclimated to 8°C the coelomic fluid pO2's are lower than in those acclimated to 24°C.

Oxygen equilibrium curves of Limulus hemocyanin are shifted to the left at a lowered temperature.

The possible respiratory adaptations of Limulus to low environmental oxygen and their ecological significance are discussed.
Rabbit blastocoele pH
Authors: Cross M. H.
Published: June 2005

Antimony pH microelectrodes were used to measure the pH of blastocoele fluid (pHb) of the six‐day intact rabbit blastocyst. The average pHb of blastocysts measured a short time after collection in a medium containing 25 mM HCO3− at 5% CO2 in air was 7.49 ± 0.03 (S.E.). The pHb of blastocysts incubated in vitro was affected by changes in P and external bicarbonate ion concentration. In general, variations of pH of the medium bring about changes in pHb in the same direction. On the assumption that the changes in pHb were due to H+ movement across the blastocoele wall, a H+ flux of 1.8 × 10−8 mole/cm2/sec was calculated. The corresponding H+ permeability coefficient was 8 × 10−2 cm/sec. It is concluded that H+ is passively distributed across the blastocoele wall.
The nerve fiber content of Amblystoma aneurogenic limbs
Authors: Egar M. , Yntema C. L. , Singer M.
Published: June 2005

The nerveless state of larval Amblystoma limbs rendered aneurogenic by removal of the embryonic neural tube and crest was examined in silver stained light microscope sections and in sections prepared for electron microscopy. The regenerates of these forelimbs were similarly studied. The sections were compared with those taken from the limb and regenerate of normal animals to which the aneurogenic animal had been parabiosed for survival. Nerve fibers were found in 62% of the “aneurogenic” limbs studied at ultrastructural levels. The number of fibers was less than one‐tenth of that in the normal limb and thus well below the expected level required for regeneration. The number of fibers counted with the electron microscope exceeded those observed with the light microscope, emphasizing the limitations of silver stains for the small unmyelinated axons.
Ontogeny and localization of the crystallins during embryonic lens development in Xenopus laevis
Authors: McDevitt David S. , Brahma Samir K.
Published: June 2005

The time of appearance and histological localization of the crystallins, especially the lens‐fiber specific γ crystallins, in the normally developing lens of Xenopus laevis were determined by immunofluorescence techniques. Antibodies to total soluble lens proteins as well as to purified γ crystallins were applied to sections through the eye region of X. laevis embryos, Nieuwkoop‐Faber Stages 23–45. Seven stages of lens development, the earliest highly atypical, were recognized in this species. The first positive immunofluorescence reaction for both the anti‐total and anti‐γ crystallin antibodies occurred at Lens Developmental Stage 3. At this time the lens rudiment is irregular and flattened, with a slightly‐condensed central mass of cells. These centrally located cells, probably prospective primary lens fiber cells, are positive for γ crystallins, while both they and surrounding retinally‐oriented lens cells are positive for total lens crystallins. This general immunofluorescence profile continues during lens development, with only the lens fiber areas positive for γ crystallins. No reaction with either antibody type, however, could be detected in the corneally‐oriented external layer or, later, the lens epithelium, until very late in the development of the lens (Nieuwkoop‐Faber Stage 45). The lack of crystallins in this cell type, together with the transitory appearance of a lens vesicle (lens cavity), delayed until after fiber cells have been formed, sets X. laevis morphological and biochemical lens development apart from that of other vertebrates.
The effects of inhibitors of RNA synthesis (α‐amanitin and actinomycin D) on preimplantation mouse embryogenesis
Authors: Golbus Mitchell S. , Calarco Patricia G. , Epstein Charles J.
Published: June 2005

Actinomycin D and α‐amanitin (an inhibitor of RNA polymerase II) were used to determine the effect of inhibiting RNA synthesis during pre‐implantation mouse embryogenesis. Actinomycin D (0.01 μg/ml) was an effective inhibitor of blastulation and of cleavage from the 1 cell stage on. The first cleavage of day 0 (1 cell) embryos cultured for 24 hours in α‐amanitin (10−7 to 10−5 M) was reduced to 35‐42% from a control value of 60%. Cleavage of day 1 (2 cell) embryos and day 2 (8–12 cell) embryos was only modestly inhibited during the first 24 hours of culture in α‐amanitin, but development beyond that point was seriously impaired. Day 3 morulae were inhibited from blastu‐lating although the degree of inhibition was not dose related. Electron microscopy of embryos cultured in α‐amanitin revealed predominantly nucleolar changes.

No difference in the activities of hypoxanthine‐guanine phosphoribosyltrans‐ferase (HGPRT) and guanine deaminase were found in morulae developed from the 4 cell or later stages in control medium or medium containing 10−5 M α‐amanitin, despite an 87% inhibition of leucine incorporation into protein. Neither the normal rise in HGPRT activity nor the normal fall in guanine deaminase activity occurred in the morulae developed from the 2 cell stage in the presence of α‐amanitin, even though both α‐amanitin treated and control embryos had the same number of blastomeres.

It is suggested that RNA synthesis is necessary throughout the mouse pre‐implantation period, including the 1 cell stage.
A qualitative analysis of the form, function and interrelationships of fat body and associated tissues in adult ticks (Acari‐ixodoidea)
Authors: Obenchain Frederick D. , Oliver James H.
Published: June 2005

Tick peripheral and central fat body (FB) contains distinct acidophilic and basophilic cell types. Previous workers call them trophocytes and nephrocytes, respectively, but overlapping physiological functions make histological descriptors more serviceable. Acidophils in Argasidae and Ixodidae contain sudanophilic vacuoles with localized caps showing nonspecific esterase activity. They are implicated in trophic lipid storage but also contain carbohydrate and protein. FB acidophils are also implicated in purine metabolism and may serve the function of insect urate cells. Basophils may contain abundant carbohydrate and protein but little lipid. Pinocytosis of dyes and incorporation of presumptive hemoglobin derivatives implicates them in deposit excretion. Pinocytosis by hemocytes, pericardial cells, Malpighian tubules and basophils indicates a probable division of labor in uptake of various sized particles from tick hemolymph.

Differentiation of central FB is coordinated with maturation of reproductive organs, usually in response to adult blood meals. There is a simultaneous development of central and peripheral FB only in ixodid females. Timing and extent of FB differentiation implicates these tissues in vitellogenic processes associated with the extensive fecundity and strict gonotrophic requirements of female ixodids. Absence of peripheral differentiation in male ixodids and most argasids appears related to persistence of gonotrophic rhythms. Ixodid peripheral FB autolysis may be related to connective tissue formation or reproductive development but should also release tick symbiotes or agents of disease. Resulting increases in circulating titer should significantly affect the vector capacity of ixodid ticks.
Cleavage initiating activities of sperm fractions injected into the egg of the medaka, Oryzias latipes
Authors: Iwamatsu T. , Ohta T.
Published: June 2005

Fractions of sperm homogenates from various animals (medaka, loach, toad, and rat) have been injected into unfertilized mature eggs of the medaka, Oryzias latipes, to test their cleavage‐initiating activity (CIA). The relationship between CIA and components of each fraction was also examined by observation with an electron microscope. It was found that there was high CIA in the fraction containing flagella or microtubules, but little CIA in the supernatant fluid without them. The CIA was closely related to the concentration of flagellum components and had no species‐specificity. However, further development after the blastula stage might be influenced by a species‐specific factor(s) of some flagellum components.
Regulation of trehalose synthesis in the silkmoth Hyalophora cecropia: The role of magnesium in the fat body
Authors: Jungreis Arthur M. , Jatlow Peter , Wyatt G. R.
Published: June 2005

During the larval‐pupal transformation of the cecropia silkmoth, the concentration of magnesium in the fat body declines from about 40 to 20 mEq/I cell water, while intracellular trehalose drops to a similar extent. Among fullygrown larvae and early pharate pupae, the hemolymph trehalose level (which is close to the fat body trehalose level in these stages) is correlated with the concentration of magnesium in the fat body but not with that in the hemolymph.

Injection into larvae, of sufficient magnesium chloride to double the magnesium content in the hemolymph, did not lead to elevated magnesium in the fat body.

It is concluded that the concentration of magnesium in the fat body is regulated independently from that in the hemolymph. Since the trehalose phosphate synthetase is activated by magnesium, the concentration of magnesium in the fat body may play a significant role in regulating the rate of synthesis, and hence the steady state level, of trehalose.
Behavioral and physiological studies of a convulsing mutant chicken (Gallus domesticus)
Authors: Kuenzel Wayne J. , Rubenstein James B.
Published: June 2005

Female chicks carrying a recessive lethal, sex‐linked gene designated px (paroxysm) develop seizures. In a population of px chicks (hemizygous females), the mean age of showing the first seizure is 19 days. The seizure syndrome can be generally divided into four phases: (1) alert phase (vocalization and/or running), (2) clonic phase (wing flapping, legs flex), (3) tonic phase (opisthotonos), and, (4) recovery phase. Seizures are spontaneous and recurrent but can also be precipitated by various environmental stimuli or by electrical stimulation of brain. Electroencephalogram recordings during seizures consistently show repetitive high amplitude spikes. Dilantin and sodium pentobarbital were effective in inhibiting electrically induced convulsions. No gross brain lesions were detected with light microscopy.
Lactate dehydrogenase and glycerol‐3‐phosphate dehydrogenase gene expression during ontogeny of the mosquito (Anopheles albimanus)
Authors: Ved Brat Sharanjit S. , Whitt Gregory S.
Published: June 2005

The specific activities (and activity per organism) of L‐lactate dehydrogenase (LDH) and glycerol‐3‐phosphate dehydrogenase (G3PDH) were determined for developmental stages of the mosquito Anopheles albimanus. The G3PDH specific activity is initially quite low, then undergoes a 5‐fold increase in the fourth instar larva. During the transitional pupal stage to adult, enzyme activity increases 25‐fold. The LDH specific activity in larval stages is initially about 100 times greater than that of G3PDH and reaches a peak in the late fourth instar larva. A 7‐fold decrease in LDH activity occurs just before moulting to early pupa. However, in contrast to reports for Drosophila, there is then a 3‐fold resurgence of LDH activity from pupal stage to the adult, mainly in the abdominal region. This is the same period in which G3PDH activity increases dramatically, primarily in the thorax. Thus, there is more than one pattern of gene expression for LDH and G3PDH within developing diptera.
The tail‐darkening reaction of phyllomedusine tadpoles
Authors: Bagnara Joseph T.
Published: June 2005

A tail‐darkening reaction is described for tadpoles of the phyllomedusine frogs, Agalychnis dacnicolor and Phyllomedusa trinitatus. Tails are pale in the light because melanophores in the dermis of the fin are punctate. In darkness the melanophores become dendritic and the tail appears black. This photosensitivity is local since tail‐darkening in isolated tails and in intact tadpoles occurs equally well. Tails cultured for many days retain fully the capacity for tail darkening. Correlations between tail darkening and filter feeding and swimming are made from comparisons with Xenopus tadpoles.
Morphogenetic interactions between minced limb muscle and transplanted blastemas in the axolotl
Authors: Dinsmore Charles E.
Published: June 2005

The regeneration blastema when autoplastically transplanted to the enucleated orbit of a larval axolotl will differentiate only those structures which lie distal to the level of its origin. Minced limb muscle treated in the same manner will reorganize into muscle, however imperfect, but form no regenerate. When a distal limb blastema is superimposed on minced limb muscle in the orbital site, it produces structures proximal as well as distal to the original level of amputation. Epimorphic regeneration therefore appears to be dominant over tissue regeneration of minced muscle and hypermorphogenesis may be elicited from a distal blastema by augmenting the mesenchymal mass with minced limb muscle.
Effect of pituitary extracts on the hypophysial gonadotrophes and its relation to the spermatogenesis in Rana hexadactyla Lesson
Authors: Kasinathan S. , Basu S. L. , Sriramulu V.
Published: June 2005

Pituitary extracts from 560 mature Rana hexadactyla of both sexes from winter and summer seasons were collected locally and were injected into frogs from summer and winter months. The adenohypophysial gonadotrophes were studied from normal animals and from the animals injected with pituitary extracts. The pituitary cell types changed in experimental frogs in comparison to the corresponding cells of normal animals. An attempt has been made to correlate the changes of gonadotrophes with changes in spermatogenetic proliferation as reported earlier (Kasinathan and Basu, '72).
Influence of the nutritional state on repeated head regeneration, growth, and fission in the planarian, Dugesia dorotocephala
Authors: Nentwig M. Ruth , Schauble Muriel K.
Published: June 2005

Starved and fed animals were repeatedly decapitated to determine the influence of nutritional state on regeneration rate and capacity, growth in length, fission, and formation of abnormal heads in Dugesia dorotocephala. Animals fed at the end of each regenerative period were able to regenerate a maximum of 40 times, with no significant change in regeneration rate compared to controls decapitated once. Growth in length of the whole animal continued throughout the study and fissioning capacity was maintained. Abnormal head formation was minimal. However, starved animals showed a marked reduction in regenerative capacity and were unable to regenerate more than 16 times. There was also a retardation of regeneration rate, decline in growth rate, loss of fissioning capacity, and a 13‐fold increase in formation of abnormal heads compared to fed animals. Fissioning cyclicity was an interesting and unexpected finding in intact fed controls and fed and starved regenerating animals. An apparently inherent four‐week frequency pattern in fission cyclicity was observed in intact fed controls, while regenerating animals exhibited an initial three‐week cycling pattern, but an alteration occurred after eight or nine regenerations and fed animals changed to a two‐week cycle, while starved animals ceased fissioning entirely. The act of decapitation and subsequent regeneration appeared to alter fissioning cyclicity. Comparative analysis of fission, growth, and abnormal head formation in regenerating animals showed different relationships in both groups. In fed animals fission and growth were inversely related the first eight decapitations, then growth leveled off while fissioning frequency changed. After 13 decapitations fission and growth were directly related and cyclic. Starved animals showed initial fissioning cyclicity, but growth steadily declined and leveled off. Head abnormalities began to increase greatly after the ninth decapitation.
Duration of life and mortality rates in male and female phenotypes in three sex chromosomal genotypes (XX,XY,YY) in the killifish, Oryzias latipes
Authors: Fineman Robert , Hamilton James , Siler William
Published: June 2005

Males were shown to be shorter‐lived than females in most species for which data have been avaiable. The present study, utilizing phenotypic sex‐reversal in various genotypes (XX,XY,YY) of the killifish Oryzias latipes, suggests that males outlive females. The stress of producing many large eggs over the major part of the female's life was probably associated with their significantly shorter lifespan.
Maturation of mouse sperm in vitro
Authors: Hoppe P. C. , Whitten W. K.
Published: June 2005

Preincubation of sperm in medium for three hours before mixing with ova increased the number of ova fertilized after one hour, thus indicating that sperm maturation occurs in vitro. The presence of cumulus cells increased the proportion of ova fertilized as observed at two and at three hours after the addition of sperm. However, no difference in the proportion of ova fertilized after one hour of incubation was observed using fresh epididymal sperm and ova with or without cumulus cells. No additive effect of cumulus cells and sperm preincubation on fertilization was observed. Sperm preincubation for three hours in the presence of ova either with or without cumulus cells resulted in fertilization similar to that achieved by sperm preincubated in medium alone.
Subcellular localization of the first three enzymes of the ommochrome synthetic pathway in Drosophila melanogaster
Authors: Sullivan David T. , Grillo Santo L. , Kitos Robert J.
Published: June 2005

The subcellular distribution of the first three enzymes in the ommochrome eye pigment pathway were studied by means of differential centrifugation. Tryptophan pyrrolase and kynurenine formamidase are found in the soluble fraction of the homogenate. A relatively small amount of tryptophan pyrrolase, 10 to 15% of the total, is sedimentable. The head region of pupae contains approximately 15% of the total activity of the animal. The subcellular distribution of the activity of the head is not appreciably different from the distribution of activity in the rest of the animal. Therefore no evidence suggests that the enzyme exists in a particulate form specifically in the head. Kynurenine hydroxylase is judged to be a mitochondrial enzyme on the basis of its co‐sedimentation with particles containing cytochrome oxidase and by the demonstration of mitochondria in the sedimented fractions containing kynurenine hydroxylase activity. Kynurenine hydroxylase was judged not to be present in pigment granules since developmental and genetic changes in pigment granule morphology do not affect the sedimentation of kynurenine hydroxylase containing particles. These results on the three enzymes lead us to conclude that they are not organized into a single multi‐enzyme complex as has been previously suggested. A consideration of the six ommochrome deficient mutants indicates that four of these can be explained by existing data. A hypothesis which does not involve enzyme complexes is presented to account for the remaining two.
Functional units in the labellar chemosensory hairs of the mosquito Culiseta inornata (Williston)
Authors: Owen William B. , Larsen Joseph R. , Pappas Larry G.
Published: June 2005

Electron micrographs of the labellar chemosensory hairs of the mosquito show that these sensilla have either three or four dendrites extending the length of the shaft. At the tip of each hair is a circular pore. The dendrites are enclosed within a scolopoid structure. At the distal end of the dendrites the microtubules are arranged in a random manner, but, in the proximal area, they are grouped into nine pairs. Near the base the pairs assume a spiral pattern giving rise to a three‐compartmented structure which forms the root proper.

Action potentials were recorded from the hairs, using NaCl at concentrations of 0.002 M to 1.0 M. Four different spikes were recognized — water and three salt. The salt spikes were labeled Types a, b, and c. None of these is identical with the L spike from the blowfly. All four spikes were recorded from some hairs which were certainly those with four dendrites.

Behavioral studies demonstrated that the rejection threshold of NaCl for labellar hairs was 0.28 M. This coincides with a rapid increase in the electrical activity of the Type c salt cell. From behavioral and electrophysiological evidence it was concluded that acceptance by Culiseta of NaCl in aqueous solution is the result of activity of the water receptor plus input from the salt receptors Types a and b, and that rejection results from activity of the Type c salt cell.
Non‐visual light responsiveness in the pigeon: Developmental and comparative considerations
Authors: Heaton Marieta Barrow , Harth Marshall Stephen
Published: June 2005

Non‐visual responsiveness to photic stimulation was investigated in pigeon embryos (days 11½–17½ of incubation) and neonates (6–24 hours posthatch). At all ages observed, these animals exhibited a marked overt response to light onset, a response which occurred even when the entire head was occluded from light, but which could be blocked (in hatchlings) by covering all of the body except the head. It was therefore concluded that retinal or direct brain mediation did not underlie the response, but rather, some form of dermal sensitivity would best account for it. Chicken embryos (day 19 of incubation) and Ring dove hatchlings (12–24 hours posthatch) were similarly investigated. Although there was evidence in both of these species for light‐contingent motility, their responsiveness was seemingly mediated by either visual or direct brain stimulation, since occlusion of the head eliminated the effect. Thus, of the three species tested, only the pigeon appeared to possess the non‐visual dermal light sensitivity. Possible significance of this responsiveness for this species was discussed.
Development of lethal yellow (Ay/Ay) mouse embryos in vitro
Authors: Pedersen Roger A.
Published: June 2005

Preimplantation embryos from matings between mice heterozygous for the yellow allele (Ay) of the agouti locus were cultured in vitro and their development was compared with embryos from control matings (Ay/a × a/a). No morphological abnormalities were consistently observed at the eightcell stage, but after 24 hours of culture there were abnormalities in 16.8% of embryos from Ay/a × Ay/a matings. The abnormalities, which consisted primarily of arrest of several blastomeres and their exclusion from the embryo, were also present in 23.9% of embryos removed from the uterus as morulae and blastocysts. Those embryos that became abnormal during preimplantation stages were presumed to be the Ay/Ay homozygotes because their frequency approximated the Mendelian expectation of 25% in Ay/a × Ay/a matings but not in control matings. The morphological abnormalities indicated an effect of the Ay allele as early as the fourth cleavage division.

Presumed Ay/Ay early blastocysts collapsed and died without hatching when cultured for five days under conditions that allowed normal embryos to hatch and grow out on the substrate. If the zona pellucida was removed from these blastocysts before culture, limited trophoblastic outgrowth occurred, but the outgrown cells were few and small and the inner cell mass disintegrated entirely.

The Ay allele in the homozygous condition thus appears to be a cell lethal that allows growth up to the early blastocyst stage but prevents the normal postblastocyst growth and differentiation of either trophoblast or inner cell mass.