bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nucleotide phosphatase in Strongylocentrotus purpuratus eggs. I. Localization
Authors: Schmidt Waldemar A. 
Published: June 2005

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractSensory 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

AbstractIntact 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

AbstractColumn 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

AbstractFemales 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

Abstract

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

AbstractAntimony 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

AbstractThe 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

AbstractThe 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

AbstractActinomycin 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

AbstractTick 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

AbstractFractions 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

AbstractDuring 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

AbstractFemale 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

AbstractThe 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

AbstractA 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

AbstractThe 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

AbstractPituitary 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).