bluuebunny/crossref_metadata_2025 huggingface dataset:
The function of hemocyanin in respiration of the blue crab Callinectes sapidus
Authors: Mangum C. P. , Weiland A. L.
Published: June 2005

Blood PO2 in the blue crab Callinectes sapidus, a very active species of tropical origin, is lower at 22°C than that of larger crabs in colder waters. These low oxygen levels permit its hemocyanin to be highly oxygenated at the gill, and to deliver almost half of its oxygen to the tissues in resting animals. Sustained muscular activity results in conspicuous decreases in blood PO2, pH and hemocyanin oxygenation. Although the venous reserve is fully utilized, hemocyanin oxygenation at the gill decreases so much that there is no change in its total quantitative function. The large Bohr shift becomes functional during activity, but its quantitative importance is not clear.
The neural control of contraction in a fast insect muscle
Authors: Josephson Robert K. , Stokes Darrell R. , Chen Victor
Published: June 2005

The wing muscles used in singing by the katydid, Neoconocephalus robustus, are extraordinarily fast. At 35°C, the animal's thoracic temperature during singing, an isometric twitch lasts only five to eight msec (onset to 50% relaxation) and the fusion frequency of these muscles is greater than 400 Hz. Stimulating the motornerve to a singing muscle initiates a short (2.5 msec at 35°C), sometimes overshooting depolarization of the muscle fibers. Despite their spike‐like appearance, the electrical responses are largely synaptic potentials. The muscle membrane appears to be capable of only weak, electrically‐excitable, depolarizing electrogenesis. The short synaptic potentials result in part from rapidly‐developing delayed rectification, in part from a low resting membrane resistance (Rm = 162 Ωcm2) and a concomitantly short membrane time constant (about 1.5 msec).
In vitro regression of cement gland epithelium from Xenopus laevis
Authors: Lyerla Timothy A.
Published: June 2005

The development of Xenopus laevis cement gland ectoderm cultured as epidermal vesicles from neurula stage embryos is described. The life cycle explanted gland cells closely parallels that seen in intact animals. The cells increase in height, extrude their secretory mucin and most of the oocyte pigment granule inclusions, and then regress. The entire sequence takes from 16 to 21 days at 18°C. The vesicles show no obvious changes in general appearance after gland cell senescence and remain viable up to 35 days of culture. Cement gland development progresses normally then in the absence of any influences that might come from the embryo and appears to be an autonomous sequence of the gland cells once they begin to differentiate in early neurula stages.
The avoidance of D‐tryptophan by the nematode Caenorhabditis elegans
Authors: Dusenbery David B.
Published: June 2005

In chemotactic studies employing countercurrent separation the nematode Caenorhabditis elegans was found to avoid D‐tryptophan with a threshold in the range 10−4 to 10−3 M. There was no response to L‐tryptophan up to 10−2 M although it appeared to partially in hibit the response to D‐tryptophan.
Water states and water gates in osmotic processes, and the inoperative concept of molfraction of water
Authors: Scholander P. F.
Published: June 2005

An historical account is given of concepts regarding the mechanism of osmosis and imbibition, starting with Lord Kelvin's gravitational column, where he pointed out that a capillary standing in a dish of water within an isothermal enclosure must have a lowered vapor pressure at its elevated meniscus so as to match that emanating from the surface in the dish, otherwise distillation would violate the Second law. A brilliant sequence to this simple idea followed through Poynting, Arrhenius, Noyes and culminated with Hulett, who in 1901 formulated the “solvent tension theory” of osmosis, stating in essence that the thermal motion of the solute molecules by impact with the free solvent surface put the solvent under tension. This lowers the vapor pressure and thereby also its freezing point. Perrin, in famous experiments on Brownian motion, demonstrated solute‐solvent independence within a solution and further support came through Herzfeld, Mysels and Duclaux. We measured negative pressures in saltfree sap of mangroves and other plants matching the osmotic pressure in the leaf cells. A series of measurements on magnetic and gravitational effects on osmotic pressure likewise bore out the tension theory. The fashionable “water concentration theory” is left experimentally contradicted and in violation of the Second law.
The role of sex hormones in the growth of antler bone tissue. I: Endocrine and metabolic effects of Antiandrogen therapy
Authors: Bubenik G. A. , Bubenik A. B. , Brown G. M. , Wilson D. A.
Published: June 2005

Cyproterone acetate (CA), an antiandrogenic compound, was used in order to investigate the role of testosterone in bone growth processes. The formation of Haversian systems in the growing antlers of white‐tailed deer (Odocoileus virginianus) were substantially affected by only 3.5 mg of CA kg/wk. The mineralization processes of the bone matrix were almost completely blocked and the antlers persisted in growing throughout the whole year. Plasma levels of thyroxine, alkaline phosphatase and GH were higher while cortisol and testosterone levels were lower than in controls. No differences were registered in plasma levels of Ca, P or urea nitrogen. Despite hypertrophy of interstitial tissue, spermatogenesis was almost completely blocked. The sexual behaviour and the body appearance of experimental animals was typical for castrates.
Structural and functional heterogeneity in an insect muscle
Authors: Stokes Darrell R. , Josephson Robert K. , Price Rebecca B.
Published: June 2005

Singing muscles of the katydid, Neoconocephalus robustus (Insecta, Tettigoniidae) are neurogenic, yet perform at contraction‐relaxation frequencies as high as 212 Hz (Josephson and Halverson, 71). The mechanical and electrical responses of different bands of one of these muscles (the dorsal longitudinal muscle, DLM) has been examined with respect to ultrastructurd features of each part which may be related to muscle performance. The DLM is composed of three bands and is innervated by four motoneurones. The cell bodies of three of these motoneurones occur ipsilaterally in the prothroracic ganglion; the cell body of the other motoneurone is contralateral in the mesothoracic ganglion. Three of the motoneurones (as yet unidentified fast axons) initiate extraordinarily fast twitches (rise time = 7.3 msec, half duration = 14.3 msec, 25 C), the fourth (an unidentified slower axon) evokes twitches which are considerably slower (rise time = 18.9 msec, half duration = 5.10 msec). Whereas the ventral and medial bands of the muscle are innervated only by fast axons (some fibers of the medial band are doubly innervated), the dorsal band is innervated by both a fast axon and the slower axon. A few fibers of the dorsal band are doubly innervated. The structure of fibers from the ventral and medial bands is very similar, with short sarcomeres (4.0 and 4.3 μm, respectively) and thin strap‐like myofibrils delineated by well‐developed sarcoplasmic reticulum (SR). Twenty‐four percent of the volume of ventral band fibers is SR and the diffusion distance from SR to the center of the adjacent myofibril averages 0.083 μm. Twenty percent of the medial band fiber volume is SR, with a diffusion distance of 0.118 μm. Ventral and medial band fibers contain about 40% mitochondria, and 33% myofibrils. The dorsal band fibers have longer sarcomeres (9.5 μm), and only 10% of the fiber folume is SR. The muscle fibrils of the dorsal band are larger and consequently the diffusion distance is greater (0.227 μm) than in the ventral and medial bands. Mitochondria comprise 23% of the volume of dorsal band fibers. Most dorsal band mitochondria are aggregated into distinct clumps. Although some dorsal band fibers are innervated by a fast axon and some by the slower axon, the dorsal band fibers are structurally homogeneous, suggesting that neurotrophic effects are not important in maintaining the structure of dorsal band fibers. The mechanical‐electrical performance and ultrastructure of the ventral and medial bands suggest their roll as fast, metabolically active but weak muscles, used in singing; the dorsal band as a slower but stronger muscle, perhaps involved in postural movements of the wing during singing.
Behavioral adaptation in neonatal chicks following embryonic vestibular system rearrangement
Authors: Heaton Marieta Barrow
Published: June 2005

Micro‐surgery was performed on chick embryos during the second day of incubation (45–50 hours). Either one otocyst was removed or was rotated 180° and reimplanted. The chicks' behavior was studied for 1–13 weeks after hatching. The unilateral loss or rearrangement of vestibular (and auditory) input led initially to abnormal behavior patterns, usually consisting of poor righting reflexes, deficits in locomotion, balance and pecking accuracy, and a pronounced head nystagmus. However, in every case, these abnormalities were corrected within a few days after hatching, so that the operated animals became almost indistinguishable from normal controls. Histological evidence confirmed the extent of the loss of the vestibular and auditory structures and nuclear amalgams. The observed capacity of the neonatal chick to adapt to this sensory loss or disorientation is a rather rare example of infraprimate behavioral adjustment or modifiability, contrasting with the frequent demonstrations of behavioral rigidity in lower forms.
The proportional regulation of cortical structures in a hypotrich ciliate Paraurostyla weissei
Authors: Jerka‐Dziadosz Maria
Published: June 2005

The relationships between the size of a cell and the number of some compound cortical structures (cirri and membranelles) were studied using cells of a hypotrich ciliate Paraurostyla weissei stained with protargol. The length of cells was measured, the number of AZM membranelles, frontal, transverse and left marginal cirri were counted in cells from growing populations and in miniaturized cells obtained by starvation or repetitive regeneration.

Changes in the number of cortical elements occur mainly through replacement of the whole ciliature during a morphogenetic process (division, reorganization, regeneration). In growing populations small postdividers and large predividers do not differ with respect to the number of membranelles and cirri despite the differences in size. In miniaturized cells the number of cortical elements formed decreases and is directly correlated with the length of the cell showing a proportional regulation in accordance to the cell size. Different modes of pattern regulation are discussed.
Changes in volume of the rhabdom in the compound eye of Aedes aegypti L.
Authors: Brammer J. D. , Clarin Bruce
Published: June 2005

The volume of the rhabdom in compound eyes of mosquitoes decreases upon illumination. This decrease is probably mediated by a bleaching of the visual pigment, since blue light is most effective in producing the change and red light is least effective. The reduction in rhabdom volume appears to be a result of rhabdomal membrane loss to coated vesicles and multivesicular bodies. These organelles were seen most frequently in blue adapted eyes, markedly less frequently in red adapted eyes, and only rarely in dark adapted eyes.
Mitosis in the intact and regenerating planarian Dugesia mediterranea n.sp. I. Mitotic studies during growth, feeding and starvation
Authors: Baguñà Jaume
Published: June 2005

Planarian neoblasts, the only cell type in this organism endowed with mitotic power, decrease in density as total body volume, total cell number, and length increase. Studies on mitosis show that the neoblast mitotic rate is a function of body length, being lower as the organism increases in length. The cephalo‐caudal distribution of mitotic figures in animals of different sizes shows a change towards a more even distribution of mitosis jointly with a mitotic increase in the caudal regions as length increases. However, in the sagittal and dorso‐ventral axes, the distribution of mitosis is always nonuniform, probably due to the uneven distribution of parenchymal tissue along them.

The pharynx of animals in all size groups examined shows no mitotic figures except some near its base. This may suggest for this organ a proximal type of growth with some cell migration.

Feeding elicits a very rapid increase in mitosis which lasts for almost a week, whereas long periods of starvation do not cause a significant increase or decrease in the basal mitotic rate. All these results stress the need of looking at the planarian neoblast mainly as a stem or replacement cell of most differentiated cell types and not as a mere “regeneration cell.” The implications of the results obtained for the mechanisms of growth and shrinkage are discussed.
Regional specialization for export protein synthesis in the male cricket accessory gland
Authors: Kaulenas M. S.
Published: June 2005

The accessory gland of the male cricket, Acheta domesticus, is a polytubular structure which produces a complex mixture of proteins used in the formation of the spermatophore. The synthetic capacity of individual accessory gland tubules has been analysed by micro‐scale SDS‐polyacrylamide gel electrophoresis. For the large and intermediate size tubules (approximately 300 in number), between 29 and 32 distinct protein synthetic patterns have been detected for individual tubules, with most of such patterns assignable to tubules at specific locations in the gland.

Analysis of labelled nascent peptide distribution on polysomes confirms regional heterogeneity in protein synthetic capacity and also demonstrates a corresponding regionality in the distribution of active messenger RNAs. Other experiments indicate that tubules with identical products can have different extents of protein labelling, suggesting that a capacity to regulate either precursor uptake or protein synthetic rate exists at the level of the individual tubule.
Cleavage initiation activities of microtubules and in vitro reassembled tubulins of sperm flagella
Authors: Iwamatsu T. , Miki‐Noumura T. , Ohta T.
Published: June 2005

Cleavage of fish (Oryzias latipes) eggs was induced by injection of heterologous (sea urchin Hemicentrotus pulcherrimus and oyster Crassostrea gigas) sperm microtubules. Cleavage initiating (CI) activity of microtubules was higher in 3% PVP suspension than in 6% BSA, and not affected significantly by the concentration of microtubules themselves. The CI activity of microtubules suspended in 3% PVP was comparatively stable in the frozen state. Heat‐treatment at more than 55°C resulted in the loss of most or all of their CI activity. Such activity was observed in side‐by‐side aggregates of tubulin linear polymers of sea urchin (Hemicentrotus pulcherrimus) spermatozoa but not in dispersed linear polymers or tubulin dimers. Microtubules with CI activity seem to participate in initiating cleavage as astral centers, or a “seed” for polymerization of ooplasmic tubulins in activated eggs.
The relationship between blood PH, ammonia excretion and adaptation to low salinity in the blue crab callinectes sapidus
Authors: Mangum C. P. , Silverthorn S. U. , Harris J. L. , Towle D. W. , Krall A. R.
Published: June 2005

The output of ammonia increases in dilute waters in which blue crabs absorb Na+ against a gradient, but not those in which crabs remain in salt balance with the medium. Net acid output does not clearly vary with salinity. The balance between ammonia and urea output shifts towards ammonotelism at low salinity. These results, and the temporal responses of blood NH4+, Na+ and Cl‐after a salinity change, support the hypothesis that excess ammonia in blood plays an important role in osmoregulation as well as opposing the effect of salt reduction on the oxygen transport system.
Neurohemal organ extracts effect the ventilation oscillator in crustaceans
Authors: Berlind Allan
Published: June 2005

Extracts of the pericardial organs of crabs injected into intact animals cause an increase in the frequency of scaphognathite beating. The active factor is not dopamine or 5‐hydroxytryptamine, which are present in pericardial organs; it is probably a peptide. The factor may represent a hormonal mechanism of coordinating heart rate and ventilation.
The sulfatides and some histochemical correlations of the lachrymal glands involved in salt secretion in Chelonia
Authors: Bolognani L. , Gerzeli G. , De Piceis Polver P. , Magnani P.
Published: June 2005

High concentrations of sulfolipids (four fractions having different hexose/sulfate ratio), intense enzyme activity (ATPase, oxoreductases) and evidence of mucines (staining with PAS and Alcian blue) in intercellular spaces were found in the lachrymal glands of Caretta caretta and Malaclemys terrapin adapted to sea water. In addition, the supranuclear region of the gland cells in Malaclemys terrapin is filled with mucin granules.

These biochemical and histochemical observations indicate that these glands have a function in salt secretion in both species and are also consistent with a function of mucous secretion exclusively in Malaclemys terrapin.

Limited signs of hypotrophy are not accompanied by changes in concentrations of sulfolipids in Malaclemys terrapin adapted to fresh water; only the reactions for enzyme activities are less intense. The mucous secretion is not affected, whereas, in correlation with changes in salt secretion, the change in ATPase activity is most conspicuous.

The correlations between the different components of the gland and salt secretion are compared with salt glands of birds and elasmobranchs.
Acid phosphatase activity in the development of the cement gland in Xenopus laevis
Authors: Ling Brenda Yu‐Feng , Lyerla Timothy A.
Published: June 2005

The properties of acid phosphatase from the cement gland of Xenopus laevis embryos were investigated both biochemically and electrophoretically. The studies were made on excised glands at a preregressing stage (stage 35/36, Nieuwkoop and Faber staging series) and a regressing stage (stage 45). The total activity (amount of p‐nitrophenol released/hr/gland) of acid phosphatase increased 1.7‐fold while the specific activity (amount of p‐nitrophenol released/hr/μg protein) increased 2.8‐fold from stage 35/36 to stage 45. There was some indication of a changing pH pattern during regression. Acid phosphatase activity showed a slight peak at pH 4.5 at stage 35/36 but a sharp optimal peak at pH 5.0 at stage 45. Also, there was increased phosphatase activity in both isotonic and hypotonic homogenates, in the absence of Triton X‐100, during gland cell regression. Electrophoretic separation of acid phosphatases from cement gland homogenates resolved two isozymes at stage 35/36, and two more forms appeared at stage 45. Both the quantitative and qualitative changes seen during cement gland development suggest a correlation between acid phosphatase activity and gland cell regression.
Influence of embryonic estrogens on adult feather coloration in the duck Anas platyrhynchos
Authors: Mueller Nancy S.
Published: June 2005

Embryos of the Rouen duck were treated on day 11 to 18 with a single injection of estradiol benzoate in the air chamber. After hatching, skin grafts were exchanged between male ducklings that had been treated with estrogen in ovo and control males. The results showed that the skin of male embryos can be permanently feminized to the same extent as untreated female embryos simply by exposing embryonic male skin to female sex hormones during embryogenesis.
Control of spawning in the tunicate Styela plicata by variations in a natural light regime
Authors: West Alan B. , Lambert Charles C.
Published: June 2005

The physical parameters controlling the release of gametes in Styela plicata were studied in laboratory experiments designed to simulate environmental conditions. Gravid animals left in constant light did not spawn until subjected to a minimum dark period followed by a sufficient amount of light. The maximum spawning success, determined by laboratory experiments, was found during the period between September, 1974 and March, 1975. The minimum dark adaption time, derived statistically from the spawning curve, was found to be 8 hours, 30 minutes. Increasing the dark adaption time resulted in decreasing the amount of light necessary to induce spawning. The total time for an entire spawning cycle (i.e., from the beginning of the dark adaption period to gamete release) was found to be approximately 24 hours. Field collection data supported the laboratory observations showing gamete release in the late afternoon, close to sunset. The amount of dark adaption affects the amount of light necessary to induce spawning suggesting a reversible photochemical reaction. Temperature limits for spawning in the laboratory were found to be 11–28°.
Differential cortical degradation in the two members of early conjugant pairs of Oxytricha fallax
Authors: Hammersmith Robert L.
Published: June 2005

A differential resorption of the anterior ventral cortical structures is shown to occur in early conjugating pairs of Oxytricha. The member on the pair's left resorbs the collar membranelles and the frontal and right marginal cirri; the member on the pair's right resorbs the central and posterior membranelles (lapel) of the adoral zone of membranelles. The lapel of the left member then aligns with the collar of the right member to form a composite structure which appears with light and scanning electron microscopy to be completely integrated. Consequently, a 4–5‐hour‐old pair contains slightly more than one complete set of anterior ventral organelles (viz., one extra set of undulating membranes) and two complete sets of ventral and anal cirri.

Analysis of conjugant pairs in which the two members are joined in abnormal positions suggests that neither the proximity of certain cortical organelles to the region of cytoplasmic bridge formation, the specific pairing position, nor the relocation of certain cortical organelles into a different cortical region is directly responsible for determining which resorption pattern occurs. Furthermore, analysis of the cortical events in conjugating doublets suggests that neither nuclear determination nor differential gene expression can account for the phenomena observed in Oxytricha.
Neurotrophic activity of brain extracts in forelimb regeneration of the urodele, Triturus
Authors: Singer Marcus , Maier C. E. , McNutt Walter S.
Published: June 2005

The loss in protein synthesis which the regenerating forelimb of the newt suffers after denervation can be recovered by infusing into it an extract of newt soluble brain protein. Moreover, the synthesis of basic protein shows a greater response to the active brain principle than does that of acidic protein. The active agent of the nervous tissue is destroyed by heat and trypsin digestion. Extracts of liver and spleen, similarly prepared, do not evoke recovery of lost protein synthesis. Synaptosomal extracts of the frog brain also cause recovery of protein synthesis in the denervated regenerate, demonstrating the likelihood that the active agent is not species‐specific within these amphibians, that it is a constituent of the neuronal fraction of nervous tissue, and that it is present in axonal terminals. Additional experiments showed that the nervous agent is likely a basic protein, and that the amount of protein infused is of the order of only 1.0% of the total regenerate protein. The significance of the findings is discussed in relation to the nature of the effect on protein synthesis and the nature of the active principle.
Genetic control of cell differentiation in platyfish‐swordtail melanomas
Authors: Vielkind Ursula
Published: June 2005

In certain fish hybrids, malignant transformation of pigment cells is due to the presence of a tumor gene (Tu), the action of which is controlled by several regulatory elements. Absence of these controlling genes causes rapid proliferation of the Tu‐transformed cells and ultimately results in melanoma formation. One of these genes has been identified as a differentiation gene (Diff), since it seems to control the differentiation of the transformed pigment cells. Light and electron microscopy of Tu‐transformed cells of fish differing in the dosage of Diff, and the determination of tyrosinase activity in homogenates of the respective tissues revealed that the degree of cellular differentiation depends on the dosage of Diff present in the genome. It is concluded that the gene Diff promotes the differentiation of malignant melanoma cells into benign melanophores.
The effect of thymectomy at different stages of larval development on the immune response of the clawed toad to sheep erythrocytes
Authors: Horton J. D. , Rimmer J. J. , Horton Trudy L.
Published: June 2005

The role of the thymus during the first three weeks of larval life in the maturation of humoral immunity in the amphibian, Xenopus laevis, is examined. Thymectomy throughout this period dramatically affects the heterologous red cell response of young adults. Sheep erythrocyte (SRBC) administration elicited haemolytic antibody production in the blood and in the spleen (measured by the appearance of plaque forming cells) of control animals, but failed to do so in all thymectomized toadlets. Moreover, use of the immunocytoadherence assay, which proved to be a sensitive test for SRBC reactivity in control Xenopus, indicated a complete absence of induced responsiveness to this antigen in the spleens of thymectomized toadlets, even in those animals thymectomized as late as 22 days of age.

In contrast to allograft immunity in Xenopus, which is suppressed only by thymic ablation during the first two weeks of larval life, the development of reactivity to heterologous erythrocytes therefore requires an additional period of thymic influence during ontogeny. These experiments support a concept of thymus‐dependent cell heterogeneity in amphibians.
Stromal induction and specification of morphogenesis and cytodifferentiation of the epithelia of the mullerian ducts and urogenital sinus during development of the uterus and vagina in mice
Authors: Cunha Gerald R.
Published: June 2005

Homotypic and heterotypic recombinations were prepared with trypsin‐separated epithelium and stroma from uterus of 1‐ to 9‐day‐old and vagina of 2‐ to 150‐day‐old mice. Growth of homotypic recombinants in adult female hosts resulted in normal uterine and vaginal morphogenesis. Heterotypic recombinants composed of uterine stroma and vaginal epithelium (VE) usually formed uterus, while recombinants composed of vaginal stroma and uterine epithelium (UE) usually underwent vaginal morphogenesis.

The development response of these heterotypic recombinants was age‐dependent. Epithelia (UE and VE) from mice two to five‐days old were responsive to stromal induction. However, from days 5 to 9 postpartum a progressive loss in competence was observed in both epithelia, and vaginal epithelium nine or more days old was unresponsive to heterotypic inductores. Inductive activitves of uterine stroma were demonstrated in 2‐ to 7‐day‐old neonates and of vaginal stroma in 2‐ to 150‐day‐old mice. These results indicate that establishment of the regional specification of Mullerian and sinus epithelium during uterine and vaginal morphogenesis is due to inductive activities of the stroma.
Composition of bladder urine of the coelacanth, Latimeria chalumnae
Authors: Griffith Robert W. , Umminger Bruce L. , Grant Blake F. , Pang Peter K. T. , Goldstein Leon , Pickford Grace E.
Published: June 2005

Major inorganic electrolytes and organic solutes were measured in urine obtained from the bladder of a live specimen of the coelacanth, Latimeria chalumnae, and the results were compared with data on blood serum from the same fish. Osmolarity is essentially identical in the two fluids. Magnesium, phosphate, sulfate, creatine, creatinine and glucuronate are highly concentrated in the urine whereas chloride, bicarbonate, protein and glucose are much lower in urine than in serum. There are moderately higher levels of potassium, total amino acids and total carbohydrates and somewhat lower concentrations of sodium, trimethylamine oxide and lactate in urine than in serum. Total calcium levels in urine are considerably lower than serum total calcium, but are slightly higher than the dialyzable calcium fraction of serum. Urea levels in urine and serum are identical.
Some respiratory characteristics of the blood of four Antarctic fishes
Authors: Raymond J. A. , Devries A. L.
Published: June 2005

Oxygen equilibrium curves of blood form four antarctic fishes were obtained at subzero temperatures. Oxygen contents were measured directly and the results on two of these fishes agreed favorably with previous studies in which oxygen electrodes were used.
The oral apparatus ofTetrahymena pyriformis, Strain WH‐6. II. Cytochalasin B inhibition of oral apparatus morphogenesis
Authors: Gavin R. H.
Published: June 2005

The effects of cytochalasin B on oral apparatus morphogenesis and cell division were studied in synchronizedTetrahymena pyriformis, strain WH‐6, syngen 1. Cytochalasin B brought about the rapid arrest of oral apparatus primordium development when added prior to the completion of oral apparatus membranelle differentiation. Cells arrested in development did not divide. When cytochalasin B was added after this transition point, oral apparatus morphogenesis and cell division were completed. The effects of cytochalasin B could be reversed by washing it from the medium. Even though cytochalasin B (at 400 μg/ml) reduced protein synthesis by 30%, the data are consistent with the interpretation that cytochalasin B prevents an assembly process during the membranelle differentiation phase of oral apparatus development.
Fertilization acid of sea urchin eggs is not a consequence of cortical granule exocytosis
Authors: Paul Miles , Johnson James D. , Epel David
Published: June 2005

Sea urchin eggs treated with 10 mM NH4Cl release a “fertilization acid” although cortical granule exocytosis does not take place. If the eggs are inseminated following ammonia activation, the cortical reaction occurs and a fertilization membrane elevates in the absence of detectable acid release. Examination by electron microscopy of eggs fixed between ammonia activation and insemination confirms the presence of intact granules. Thus, the fertilization acid is not caused by the release of the cortical granules. Ammonia treatment of fertilized eggs stimulates further release of acid. The release of acid can occur repeatedly in ammonia activated eggs if they are washed into normal seawater between successive ammonia treatments. Our results suggest that the release of fertilization acid is related to some metabolic process which can be turned “on or off”.
In vitro utilization of exogenous procollagen by embryonic tooth germs
Authors: Galbraith Donald B. , Kollar Edward J.
Published: June 2005

Embryonic mouse tooth germs treated with L‐azetidine‐2‐carboxylic acid cease their development, undergo a regression of the enamel organ, and do not maintain the histological characteristics of the explanted dental organ. On the other hand if procollagen is added exogenously to explants continuously treated with Lazetidine, the effects of the inhibitor are not seen and the tissue is maintained. Thus, exogenously supplied procollagen supports morphogesis in tooth rudiments that are unable to synthesize procollagen.
Stability of RNA synthesized by the mouse oocyte during its major growth phase
Authors: Jahn Carolyn L. , Baran Madelyn M. , Bachvarova Rosemary
Published: June 2005

The RNA of growing mouse oocytes and ovulated ova was labeled by injection of a solution containing tritiated uridine into the ovarian bursa. The time course of incorporation into RNA by oocytes was followed by analysis of alkali‐labile acid insoluble radioactivity and by autoradiography. The results show that most of the incorporation into RNA by growing oocytes takes place within one day of bursal injection of the precursor, reflecting the rapid fall of label in the acid soluble precursor pool. The RNA of growing oocytes of all sizes is unusually stable, at least 80% of the labeled RNA present two days after bursal injection being retained until ovulation 10 to 20 days later. The fraction of heterogeneous RNA in labeled RNA of ova was estimated as 20% by sucrose gradient analysis. It is likely that egg RNA is synthesized primarily during the period of oocyte growth one to three weeks before ovulation.
A role for esterases in the fertilization process
Authors: Bradford Marion M. , McRorie Robert A. , Williams William L.
Published: June 2005

The corona penetrating enzyme of sperm is shown to be esterolytic in nature. This is the first known function of the several sperm esterases and indicates the cementing substance between cells of the corona radiata contains an essential ester linkage.
Frog lysozyme III. The effects of metamorphic inhibition on Rana pipiens lysozyme ontogeny
Authors: Ostrovsky David
Published: June 2005

The inhibition of Rana pipiens metamorphosis by thiouracil altered the ontogeny of lysozyme. Certain isozymes of the enzyme remained absent. There was, nevertheless, an increase in tissue lysozyme concentration.
Cell migration kinetics in the stomach of Styela clava (Urochordata: Ascidiacea)
Authors: Ermak Thomas H.
Published: June 2005

By autoradiography with tritiated thymidine, the rate of cell migration was studied for the groove population of epithelial cells lining the stomach of Styela. After one hour, the tritiated thymidine is incorporated into undifferentiated, dividing cells. Labeled differentiated cells appear after three days, and the migration of labeled cells to the extrusion zone takes about 16 days (T= 19°C). Stomach growth is accomplished by an increase in both number and height of epithelial folds. The percentage rate of cell migration probably remains fairly constant throughout adult life. However, it is decreased by starvation and low temperatures.
A reversible, hydrogen lon blockade of spontaneous oocyte maturation in the starfish: Locus of action
Authors: Cloud J. G. , Schuetz A. W.
Published: June 2005

Starfish (Asterias forbesi) oocytes encased within their follicle cells mature spontaneusly during a portion of the normal reproductive period when released from the ovary into seawater. A previous report has shown that oocytes isolated in acidic seawater do not mature spontaneously but retain the capacity to do so when returned to normal seawater. The object of this study was to determine the mechanism by which acidic pH reversibly blocks spontaneous oocyte maturation in isolated follicles. Incidence of spontaneous oocyte maturation in follicles isolated in acidic seawater decreased as pH decreased from 7 to 4. Oocytes in which spontaneous maturation was inhibited (ASW at pH 4.7 to 5.4) underwent germinal vesicle breakdown with the addition of 1‐methyladenine. Oocytes isolated in acidic seawater (pH 4 or 5) with intact follicle cells matured spontaneously when transferred immediately to normal seawater (pH 8); after four hours, 60‐65% of the follicles incubated in seawater at pH 5 matured spontaneously when returned to normal seawater as compared to less than 10% of the follicles maintained at pH 4. Inhibition of spontaneous maturation was not reversible in the absence of the follicle cells. Oocytes isolated in acidic seawater with their follicle cells did not spontaneously mature when transferred to calcium‐free seawater at pH 8. The results obtained support the hypothesis that acidic seawater reversibly inhibits spontaneous oocyte maturation by interfering with the release of meiosis‐inducing substance from the follicle cells.
Anesthesia as an effective agent against the production of congenital anomalies in mouse fetuses exposed to electromagnetic radiation
Authors: Rugh Roberts , McManaway Mary
Published: June 2005

A total of 130 female mice pregnant at 8 days were exposed singly to a 7.3 watt microwave waveguide at 2,450 MHz wave length while being monitored for total absorbed dose, the exposure being four minutes. Among the 1,328 offspring examined (327 of which were controls) those not anesthetized but irradiated showed greater fetal damage than those that were anesthetized and placed in one of the three positions with respect to the radiation beam. Immobilization with anesthesia and restraint in the broadside position provided the greatest protection to the fetus against any teratologic effects. Anesthesia reduces the body temperature to a degree equivalent to the rise in temperature expected from the radiation conditions used, hence the protection against the primary thermal effect of microwave irradiation.
Production of retarded, albino, regenerates in newts by alpha‐methyl‐p‐tyrosine
Authors: Taban C. H. , Cathieni M. , Constantinidis J.
Published: June 2005

Inhibition of tyrosine hydroxylase with alpha‐methyl‐p‐tyrosien retarded growth and prevented melanization of limb regenerate in adult newts (Triturus cristatus).
Body temperature of the lizard (Anolis carolinensis): Effect of parietalectomy
Authors: Roth Jan J. , Ralph Charles L.
Published: June 2005

Thermal behavior of parietalectomized, sham‐parietalectomized or intact lizards (Anolis carolinensis) was recorded in a test chamber containing moving photothermal gradients. Following parietalectomy, animals chose significantly higher temperatures than sham‐parietalectomized or intact control animals, which chose lower and statistically identical temperatures. When pre‐surgical and post‐surgical means are compared within groups, the eccritic temperature was 2.10°C higher following parietalectomy, 0.72°C higher following sham‐parietalectomy, and 0.31°C higher in intact controls during the postoperative measurements. The effects of parietalectomy indicate that the parietalpineal complex may be involved in behavioral thermoregulation by precisely regulating exposure to heat sources (e.g., sunlight).
Parietalectomy and thermal selection in the lizard Sceloporus magister
Authors: Engbretson Gustav A. , Hutchison Victor H.
Published: June 2005

Lizards were acclimatized to various regimes of temperature (15°, 35°C) and photoperiod (LD 08:16, 16:8). Parietalectomized, sham operated, and control animals were placed in thermal gradients and their body temperatures monitored for periods of up to 15 days. Daily rhythms of thermal selection were evident with higher temperatures selected in late photophase and lower temperatures selected in scotophase. Thermal selection was more variable in scotophase than in photophase. Parietalectomized lizards chose significantly higher body temperatures than did shams or controls. Acclimatization to temperature and photoperiod had little or no effect on the thermal preferendum. The preferred body temperature of controls was 33.2°C ± 3.59. Length of time in the gradient tended to change thermal preference, especially in lizards acclimated to 15°C. Through interactions with the pineal gland the parietal eye is probably important in synchronizing many bodily functions with photoperiod.
Phospholipase activity of sea urchin sperm: Its possible involvement in membrane fusion
Authors: Conway A. F. , Metz C. B.
Published: June 2005

Phospholipase activity of egg‐water treated Arbacia punctulata and Lytechinus variegatus sperm was shown to result from the sequential action of phospholipase A and lysophospholipase. A transient burst of phospholipase A activity followed induction of the acrosome reaction with egg water. The time of appearance suggested an acrosomal localization of the enzyme. The peak activity of phospholipase A correlated with initiation of sperm‐egg fusion, suggesting a role for sea urchin sperm phospholipase A in membrane fusion and/or egg activation during fertilization.
Muscle satellite cells in urodele amphibians: Facilitated identification of satellite cells using ruthenium red staining
Authors: Popiela Heinz
Published: June 2005

The ruthenium red (RR) stained forelimb musculature of three species of urodeles Triturus (Notophthalmus) viridescens, Amblystoma maculatum, Amblystoma opacum in various stages of growth were examined with the electron microscope for the presence of satellite cells. It was found that RR staining facilitated greatly the identification of satellite cells. In young larvae of all three species satellite cells were detected with a frequency of 29% to 48% per total number of nuclei. In adult Triturus and Amblystoma maculatum satellite cells were no longer detected; instead “pericytes” as described by Hay ('74) were seen with a frequency of 12% and 3% respectively. During metamorphosis of Triturus satellite cells, with part of their myofiber‐satellite cell intercellular space filled with basement membrane material, occurred at a peak frequency. The cells presumably are intermediate in the formation of “pericytes.” At ten days after metamorphosis satellite cells and intermediate cells were no longer detected and the limb musculature contained only “pericytes” similar to the ones observed in adult newts. The significance of the presence of satellite cells in relation to limb regeneration and muscle regeneration is discussed.
The effect of growth and joint formation on bristle pattern in D. melanogaster
Authors: Tokunaga Chiyoko , Gerhart John C.
Published: June 2005

Dependence of bristle pattern on size and joint formation was studied for male first leg tarsi of fj (four jointed) and d (dachs) mutants in homozygotes and in mosaics resulting from X‐ray induced mitotic recombination. Homozygotes have four tarsal segments, lacking a third tarsal joint in most cases. The two proximal segments are shortened, the first by one‐third, and altered in bristle pattern, whereas the distal two segments are little affected. Expressivity of fj is high, and of d is low, for the extent and frequency of joint failure. The longer the second segment, the more complete the third joint and the greater the bristle number. Only the jointed side of the segment approximates two segments in its bristle pattern. Mosaic studies show that joint failure occurs autonomously in fj, or in the majority of d clones, and that joint formation by heterozygous clones is autonomous except in the border area contacting a fj or d spot lacking a joint, in which area joint failure occurs. Bristle pattern in this jointless heterozygous area switches to that of a single segment. Localized nonautonomy also occurs in the t‐rows of heterozygous tissue contacting a fj or d spot. Both mutant genes are interpreted as reducing longitudinal growth of the proximal tarsi, with joint failure as a consequence, and with alterations of bristle pattern resulting directly from size reduction, or indirectly through joint failure.
Renewal of normal and degenerating photoreceptor outer segments in the Ozark cave salamander
Authors: Besharse Joseph C. , Hollyfield Joe G.
Published: June 2005

To determine whether photogoreceptor degeneration in the Ozark cave salamander is associated with cessation or changes in the kinetics of outer segment (OS) renewal, an autoradiographic study of 3H‐leucine incorporation in photoreceptors was carried out. Six days after isotope injection rods and cones showed labeling in both inner and outer segments. Cone OS were diffusely labeled whereas rods contained a band of radioactivity at the base of the OS. At 13 and 21 days the radioactive band in rods was located progressively nearer the distal tip of the OS. The rate of rod OS renewal ranged from 0.30 to 0.38 μ of OS length per day at 18°C. L‐thyroxin induced metamorphosis and light increased the renewal rate compared to larvae in darkness, and adults with photoreceptors in an early stage of degeneration had a slightly higher renewal rate than larvae. Light and electron microscope autoradiographs of degenerate photoreceptors revealed that even in the final stages of degeneration when OS are reduced to small, irregular whorls of membrane, 3H‐leucine labeling was present in inner segments and OS membranes. These observations demonstrate that OS renewal occurs in both larvae and adults, and suggest that photoreceptor degeneration may be due to disruption of some aspect of the OS disposal process.
Protein synthesis and germ plasm in cleavage embryos of Xenopus laevis
Authors: Hogarth K. , Dixon K. E.
Published: June 2005

(3H) Leucine was injected into unfertilized eggs, fertilized eggs, and Stage 2–12 embryos of X. laevis. Incorporation of the leucine into protein by blastomeres containing germ plasm was studied autoradiographically. Eggs, both fertilized and unfertilized, actively synthesized protein, as did embryos from Stage 2 onwards. Probably all blastomers containing germ plasm were labelled. In embryos from Stages 4–12, the germ plasm itself was also labelled, and this result suggests that the germ plasm is metabolically active during cleavage.
Developmental effects of exposing Drosophila embryos to ether vapour
Authors: Bownes Mary , Seiler Maxine
Published: June 2005

Drosophila embryos at precise developmental stages were exposed to ether vapour. The defects in the resulting embryos and adults were observed. Ether disrupted embryogenesis in specific ways, causing defects primarily at the anterior of the embryo and disorganizing the arrangement of the segments. Adults showed deficiencies and duplications of many imaginal disc and histoblast derivatives. Phenocopies of the bithorax mutation which transforms metathorax to mesothorax were observed. They were first induced at the syncytial blastoderm stage, had their peak of production at the cellular blastoderm, and were no longer observed after the anterior and posterior midgut were partially invaginated. It was observed that not only are the haltere/wing transformations confined to the anterior compartment, but also leg 3 to leg 2 transformations only occurred in the anterior leg compartment.
The activities of some lysosomal hydrolases in the development of the cement gland in Xenopus laevis
Authors: Hsu Teresa Wei , Lyerla Timothy A.
Published: June 2005

The hydrolases B‐glucuronidase, B‐galactosidase and N‐acetyl‐B‐D‐glucosaminidase were examined in Xenopus laevis for their pH optima, sedimentability by differential centrifugation and optimal incubation temperatures for their assays. Enzyme activities were enriched in the 20,000 × g fraction of tissue homogenates, and all three of the enzymes exhibited acid pH optima, supporting the assumption that these are lysosomal enzymes in X. laevis. Total and specific activities of B‐glucuronidase and N‐acetyl‐B‐D‐glucosaminidase were significantly higher in homogenates from regressing cement glands compared with those from preregressing glands. Cement gland regression, then is, apparently accompanied by lysosomal activation.