bluuebunny/crossref_metadata_2025 huggingface dataset:
Ontogenetic studies of cyclic AMP‐dependent protein kinase enzymes from Mouse Heart and Other Tissues
Authors: Malkinson Alvin M. , Hogy Lora , Gharrett Anthony J. , Gunderson Thomas J.
Published: June 2005

Cyclic AMP is one of the factors which regulate cell differentiation. In animals the apparent mechanism of action of cyclic AMP is the activation of protein kinase enzymes. Postnatal changes in cyclic AMP‐dependent protein kinase enzymes were therefore examined. Determinations were made of the protein kinase and cyclic AMP‐binding specific activities and of the isozyme content (as analyzed by DEAE‐cellulose chromatography) for cytosol fractions from different neonatal and adult mouse tissues. Slight or negligible differences in enzymatic activity and isozyme distribution were observed in comparisons between neonatal and adult samples obtained from brain, liver and lung. In contrast to these tissues, however, major ontogenetic changes were observed with heart. The protein kinase and cyclic AMP‐binding I activities were constant from birth until the end of postnatal week 2. Protein kinase activity decreased 40% between days 12 and 21, and cyclic AMP‐binding activity decreased 30% between days 17 and 25. Both activities then decreased gradually with age. By ten months the kinase activity had decreased 75%, and the cyclic AMP‐binding activity 60%, from the perinatal levels. In addition to these changes in specific activity there were also age‐dependent changes in the heart isozyme distribution. The apparent amounts of the Type I and Type II isozymes decreased 75% and 25%, respectively, with age. Thus, while neonatal heart cytosol contained two to three times more Type I activity than Type II, the relative activities of the two isozymes in adults were nearly equal. The fact that the most dramatic changes in the protein kinase and cyclic AMP‐binding specific activities occur at that time period when cardiac growth shifts from a mainly hyperplastic to a predominantly hypertrophic process suggests that this enzyme may have a regulatory role in heart development.
Inhibition of early events of sexual processes in Paramecium by concanavalin A
Authors: Tsukii Yuuji , Hiwatashi K.
Published: June 2005

The lectin concanavalin A (ConA) inhibited specifically an early step of sexual reproduction (conjugation or autogamy) in Paramecium caudatum. ConA (50 μg/ml) did not prevent the initial agglutinative mating reaction in natural conjugation or a specific swimming behavior observed prior to the induction of conjugation by chemicals, but inhibited pair formation which usually occurs about one hour later. Cells pretreated by protease, ficin or papain increased in their sensitivity to the inhibitory effect of ConA. Conjugating pairs once formed were not separated by the treatment with ConA and underwent nuclear changes normally. The sensitive period to ConA was proximately the first 30 minutes from the onset of mating reaction or of the chemical treatment for induction of conjugation.

The same kind of inhibition by ConA was observed in two other species, Paramecium trichium and Paramecium bursaria, but could not be demonstrated in Paramecium multimicronucleatum.

ConA (4 μg/ml) completely prevented chemical induction of autogamy in an early step but did not if applied 60 minutes after initiation of the induction. The inhibition of conjugation and autogamy was completely released by α‐methyl‐D‐mannoside or mannose, competitive inhibitors of ConA. PHA had no effect on these sexual processes.
Effect of light and dark adaptation upon the rhabdom in the compound eye of the mosquito
Authors: Brammer J. D. , Stein Peter J. , Anderson Ronald A.
Published: June 2005

During the first two hours of light adaptation rhabdom volume in compound eyes of adult mosquitoes is strikingly reduced. In females this involves a net loss of photoreceptor membrane of 500–700 μ2/cell/hour. Concurrently, numerous coated vesicles and multivesicular bodies appear in the cytoplasm adjacent the rhabdom. After longer illumination times (up to 5 hours) membrane loss averages considerably less, 220 μ2/cell/hour. Furthermore, puromycin experiments suggest that it is counter‐balanced by the formation of an equal amount of new membrane. Thus, despite substantial membrane turnover no net change in rhabdom volume takes place.

When light‐adapted mosquitoes are dark adapted for 12 to 36 hours there occurs a net increase of rhabdom membrane averaging 75 μ2/cell/hour, and a corresponding increase in rhabdom volume.
Ciliary membranes in water transport
Authors: Ciccolello Raymond F. , Gibor A.
Published: June 2005

The rate of contraction of the contractile vacuole was used as an indicator of water uptake by Paramecium caudatum. Water uptake by deciliated paramecia was found to be about half that of the controls. Normal rate returned with the regeneration of the cilia.
Genetic control of enzyme expression in Drosophila: A locus influencing tissue specificity of aldehyde oxidase
Authors: Dickinson W. J.
Published: June 2005

A natural genetic variant in Drosophila melanogaster with a highly tissue specific effect on the level of an enzyme (aldehyde oxidase) is described. This variant causes overproduction of the enzyme by a factor of 2‐ to 3‐ fold in paragonia (male accessory sex glands) while having no significant effect on the enzyme level in other tissues. This difference is controlled by a single genetic element in the vicinity of the aldehyde oxidase structural gene that operates in a strictly cis‐active mode. It is not associated with any change in enzyme primary structure detectable by a variety of physical, chemical and immunochemical tests. The most likely explanation for all of these observations is that the variant defines a cis‐active regulatory element adjacent to the structural site.
Lactate dehydrogenase C4 in male sex accessory glands of normal mice and in testes of sex‐reversed mice
Authors: Holmes Roger S. , Jones Janet T.
Published: June 2005

Lactate dehydrogenase (LDH) C4 activity was observed in testis extracts of sex‐reversed mice (Sxr) and in male sex accessory gland (seminal vesicle and prostate) extracts from C3H/He and C57BL/Go mice. These results reflect either (1) the presence of low concentrations of germinal cells in these tissues; or (2) the synthesis of LDH‐C4 by somatic cells in Sxr testes and normal male sex accessory glands.
The effect of a single epilation on successive hair eruptions in normal and hormone‐treated rats
Authors: Hale Patricia A. , Ebling F. J.
Published: June 2005

In intact female rats and in one receiving hormonal treatments which alter spontaneous follicular cycles, hairs were plucked before, during or after the spontaneous growth of G2 hairs. Several successive hair eruptions on the epilated and the contra‐lateral intact flank were then observed.

Epilation always advanced the next eruption, except that if performed during the last few days before spontaneous eruption was expected, it had no effect.

Eruption after a fixed interval characteristic of the region epilated followed the plucking of club hairs from resting follicles. After growing hairs were plucked, the interval to eruption was longer, and varied with the stage of anagen reached at epilation. Nevertheless the advance of eruption was even greater than after the epilation of resting follicles. The interval from epilation to eruption was increased by estradiol or propylthiouracil, which prolong both spontaneous and induced follicular cycles, and reduced by spaying or thyroxine, which shorten them.

Under all treatments, epilation also advanced subsequent eruptions, the second usually even more than the first. Comparison of cycle lengths of epilated and normal follicles, and correlation with observations on pulse‐labelled hairs, showed that while the first post‐epilation anagen was unaltered, the resting phase which followed it was shortened. Subsequent cycles tended to be prolonged.

Some evidence was found for a slow‐acting systemic control tending to resynchronize the cycles of epilated follicles with those of symmetrically‐placed nonapilated ones, although complete synchrony was not achieved within three or four cycles of a single epilation.
Investigations into the degree of cell mixing that occurs between the 8‐cell stage and the blastocyst stage of mouse development
Authors: Kelly Susan J.
Published: June 2005

This study was designed to assess the degree of cell mixing that occurs during the early development of the mouse embryo, and thus provide information which is important in relation to the current theories of differentiation. Previous studies of this nature have involved either chimeric composites, or have only followed a very limited number of cells in the embryo. Here the products of one of the 4‐cell stage blastomeres have been labeled with tritiated thymidine, at a level which allows their descendants to be identified three or four cell divisions later, and recombined with the remaining blastomeres of the same embryo. After fixing and sectioning of the embryos at the blastocyst stage the locations of the labelled cells have been analyzed to assess the degree of clumping that they display. A significant tendency for the products of this one 4‐cell stage blastomere to be confined to a single area in the blastocyst is demonstrated. This indicates that there is little marked cell movement during the observation period. The relevance of these results to current knowledge of blastocyst development is discussed.
Changes in internal pressure during puparium formation in flies
Authors: Zdarek Jan , Slama Karel , Fraenkel Gottfried
Published: June 2005

Changes in the internal pressure of fly larvae during puparium formation were measured by a method previously described. Two different types of pressure changes were recorded: (1) Reversible pulsations of various types corresponding to different kinds of muscular contractions, and (2) an irreversible increase of the pressure baseline caused by dimensional shrinkage and loss of elasticity of the cuticle, association with ultrastructural reorganization and sclerotization. The pressure pulses potentiated by neuromuscular activity are association with the initial stages of pupariation, immobilization, retraction of the anterior segments, and longitudinal body contraction, and can generate pressure peaks of up to 300 mm Hg. By contrast, the steady rise of the basic pressure during the final stages of pupariation is generated independently of muscular activity and is also independent of phenolic tanning. The basic pressure can reach levels of 100 mm Hg and is indispensable for the final rounding and smoothening of the ovoid puparium. Morphogenesis of the puparium thus can be understood as a result of a delicate concert between neuromuscular activity and structural changes in the integument.
Experimental analysis of lens regeneration in Xenopus laevis and Rana esculenta tadpoles by means of xenoplastic grafts
Authors: Filoni Sergio , Bosco Luigi , Cioni Carla
Published: June 2005

Lens forming capacities of the eye of Xenopus laevis and Rana esculenta tadpoles were studied by means of xenoplastic grafts. The results obtained demonstrated that the lentectomized eye of larval Rana esculenta transplanted under the outer cornea of larval Xenopus laevis was able to support lens regeneration in the outer cornea of Xenopus. This observation was confirmed by implanting the outer cornea of Xenopus into the eye cup of Rana and noting lens transformation in the implanted cornea. On the contrary, the lentectomized eye of larval Xenopus laevis transplanted under the outer cornea of Rana esculenta, was not able to allow the lens regeneration from the cornea.

These results indicate that the absence of lens regeneration in lentectomized eyes of larval Rana esculenta, demonstrated in previous researches, is due to the absence of lens forming capacity in the outer cornea of Rana.
Ultrastructure of the eggshell of two species of anoline lizards
Authors: Sexton Owen J. , Veith George M. , Phillips David M.
Published: June 2005

The role of the eggshell of two species of lizard (Anolis limifrons and A. sagrei, lguanidae, Squamata) in water transport is discussed. Levels of soil moisture in habitats of A. limifrons in Panama vary seasonally in two locales; the lowest values are attained during the dry season months of February–April. The transfer of water from the soil to the egg must be mediated by the biologically passive eggshell. The eggshells of these two species consist of five concentrically arranged zones of fibrils peripheral to the shell and egg membranes. The fibrils are covered by a granular layer containing CaCO3. This layer bounds irregular channels passing from the exterior to the interior of the eggshell. It is proposed that water moves from the soil through the eggshell by capillary.
Ultrastructure of normals and castrates and the effects of testosterone and ultraviolet (UVL‐B) irradiation on scrotal skin of rats
Authors: Glimcher Mark Edward , Flynn Evelyn A. , Szabo George
Published: June 2005

The ultrastructure of the testosterone dependent epidermal melanocyte system of the scrotal skin of normals and castrates, with and without testosterone replacement therapy, and UVL‐B (280–315 nm) radiation in black Long Evans rats is reported. UVL‐B increases melanocyte activity, melanosome forming apparatus, (size of Golgi zone and RER, and quantity of cytoplasmic vesicles, dendrites, and stages of melanosomes) in normals and in castrates. Testosterone replacement therapy to castrates is not a prerequisite for stimulation by UVL‐B, but it enhances the effects of UVL‐B without restoring normalcy as melanosome packaging into complexes predominates. After UVL‐B stimulation of normals or castrates, melanocyte dendrites are observed more often. Melanocyte dendrites of skin of castrated rats are observed less often than in normals, but with testosterone replacement therapy, the dendrites become more numerous. Melanosomes donated to keratinocytes are mostly located as singles in normals and as complexes in castrates. After UVL‐B, castration, or testosterone replacement therapy, the melanosomes are packaged in keratinocytes in complexes larger than in normals. In the epidermis of long term castrates (9–109 days), non‐specific clear cells are observed and Langerhans cells containing melanosomes; we did not observe them in normals. Melanocytes of castrates have a reduced melanosome forming apparatus. The dermis of castrates contains many dermal melanocytes in the superficial dermis with melanosomes in several stages of formation. These cells are not apparent in normals at this location in the dermis.

Testosterone replacement therapy and/or UVL‐B administered to castrates does not restore the epidermal melanocyte system nor the dermis to precastration ultrastructural appearance; castration has a permanent altering effect as melanosomes are packaged into complexes.
Influence of 3,3′,5′‐triiodo‐L‐thyronine on the involution of the cement gland of Xenopus laevis (Daudin) in vivo and in vitro
Authors: Weets J. , Picard J. J.
Published: June 2005

The cement gland of Xenopus laevis appears at stage 15. It increases rapidly in volume and reaches its maximum size five days after fertilization at 18° The growth is followed by involution and the gland eventually disappears at stage 50. The evolution of explanted glands cultured in vitro is similar to the evolution observed in vivo. The involution of explanted glands cultured in Barth solution suggests that the initiation of the involution is independent of hormonal control. However, 3,3′,5′‐triiodo‐L‐thronine increases the rate of the involution in vivo as well as in vitro and this rate is a function of the concentration of the hormone.
Xenopus oocyte cAMP‐dependent protein kinases before and during progesterone‐induced maturation
Authors: O'Connor Clare M. , Smith L. Dennis
Published: June 2005

Two cAMP‐dependent kinase activities, corresponding to the Type I and Type II isozymes characterized in other tissues, have been partially purified from Xenopus laevis oocytes both before and during progesteroneinduced maturation in vitro. The two activities are present in approximately equimolar concentrations in ovarian oocytes and the total kinase concentration has been estimated at 0.2–0.4 μM minimally. The relative activities of the two isozymes do not change during oocyte maturation.
Intrafollicular cumulus cell transformations associated with oocyte maturation following gonadotrophic hormone stimulation of adult mice
Authors: Schuetz Allen W. , Swartz William J.
Published: June 2005

Effects of gonadotrophic hormones on the intrafollicular morphological transformation of cumulus cells were examined in adult mice. Formation of transformed cumulus masses was examined during both the pre‐ and post‐ovulatory course of gonadotrophic (PMS or PMS + HCG) induction of follicular synchronization and ovulation. Within nine hours of PMS injection and prior to ovulation, transformed cumulus cell masses were present within ovaries. Injection of HCG within 48 hours of the PMS injection stimulated the formation of additional and increased numbers of pre‐ovulatory transformed cumulus cell masses. Ovulation occurred within 24 hours of both the PMS injection and the HCG injection when given to animals previously stimulated with PMS. Oocytes isolated from transformed cumulus cell masses following PMS or HCG injection had invariably undergone meiotic maturation. Transformed cumulus masses were also recovered from ovaries following induced ovulation; however, their numbers were decreased. Follicles stimulated by PMS remained sensitive to HCG (underwent ovulation) for approximately four days following a single injection of PMS. Results indicate that identifiable morphological and physiological changes in cumulus cells precede ovulation and are strongly correlated with the induction of the meiotic maturation process in the enclosed oocytes. The presence of mature oocytes in transformed cumulus masses following ovulation furthermore indicates that asynchrony of the oocyte maturation and ovulatory events are induced by the gonadotrophic hormones. Intrafollicular cumulus cell transformations are discussed in relation to dissociation of the somatic and germ cells, the mechanisms of meiotic induction and the process of atresia. Results suggest that the simple morphological changes described provide a quantitative and selective indicator of gonadotrophic action within the ovary.
The influence of inorganic ions and pH on oxygenation properties of the blood in the gastropod mollusc Busycon canaliculatum
Authors: Mangum C. P. , Lykkeboe G.
Published: June 2005

The oxygen affinity of Busycon canaliculatum blood decreases with increasing pH in the range 6.6–7.9, and increases from 7.9–8.5, which encompasses the physiological range under normoxic conditions. When inorganic ions are removed from the blood, the oxygen affinity of the hemocyanin increases, the reverse Bohr shift diminishes and the normal Bohr shift cannot be detected. The addition of physiological levels of NaCl restores much, but not all, of the oxygen affinity and the Bohr shifts remain reduced or absent. The addition of physiological levels of Ca+2 and Mg+2 to the NaCl solution restores virtually all of the oxygen equilibrium properties that characterize native blood.

When the samples are buffered with CO2 instead of Tris Maleate, the salt and pH effects change above pH 7.9, which may be due to either an indirect effect of carbon anions on divalent cation activity or a heterotropic effect of CO2 on the hemocyanin molecule.

The pH dependence of oxygen affinity changes at low temperature.
Contact inhibition of cell movement in living embryos of an annual fish, Nothobranchius korthausae: Its role in the switch from persistent to random cell movement
Authors: Lesseps Roland , Hall Marian , Murnane Mary Beth
Published: June 2005

The deep blastomeres of annual fish embryos emigrate from the blastodisc to wander as single cells, during epiboly and early dispersed stages, between the periblast and the enveloping layer cells. Time‐lapse films of the deep blastomere movements were analyzed to determine whether the cells move persistently or randomly and whether or not they show contact inhibition of cell movement. Certain predictions which follow from the random‐walk model (uniform distribution of intersegmental angles, exponential distribution of squared segmental lengths, and a straight‐line plot – passing through the origin – of mean square displacement against time) were tested and, in general, found to apply to these deep blastomeres during dispersed phase 1 but not during epiboly stages. These results indicate that the cells tend to persist in their direction of movement during epiboly, but not during dispersed phase 1, when their movement is random. Upon completion of epiboly, there is a decrease in cell motility, as measured by the augmented diffusion constant, D*, and an increase in the average collision rate. Numerous cases of cell contact between deep blastomeres were observed (297 during epiboly and 167 during dispersed phase 1); in every case one or both cells changed their direction of movement. The role this contact inhibition might play in the persistent movement of epiboly and the random movement of dispersed phase 1 is discussed.
Mitogenic effect of a growth factor derived from myelin on denervated regenerates of newt forelimbs
Authors: Mescher Anthony L. , Gospodarowicz Denis
Published: June 2005

Fibroblast growth factor injected into denervated early regenerates of adult newt forelimbs promotes mitotic activity in the dedifferentiated mesodermal cells. The effect is dose‐dependent and is not produced with similar doses of cytochrome c, bovine serum albumin, or growth hormone. Epidermal growth factor has a mitogenic effect less than half as great as that of fibroblast growth factor. The results suggest the possibility of a role for myel in‐derived growth factors in blastema formation.
Response of the avian chorionic epithelium to presumptive scale‐forming dermis
Authors: Fisher C. , Sawyer R. H.
Published: June 2005

The isolated chorionic epithelium (CE) from 8‐day chick embryos responds to the inductive influence of anterior shank (scale) dermis (ASD) in different ways depending on the age of the dermis. Eleven‐day dermis induces the fomrmation of barb‐ridges, typical of feathers, yet, very little feather elongation; while 13‐day dermis induces the CE to form normal scale epidermis. Twelve‐day ASD elicits both the formation of barb‐ridges and scales. Thus, the ASD, in association with the overlying scale‐forming epidermis, becomes altered in its inductive ability between 11 and 12 days of development.
Dissolution of rabbit zona by acrosomal extract: Effect of calcium
Authors: Srivastava Prakash N. , Akruk Samir R. , Williams William L.
Published: June 2005

The acrosomal extracts from rabbit spermatozoa were more effective in dissolving the zona pellucida of the rabbit ova in the absence than in the presence of Ca+2. The extracts had high proteolytic activity but low esterolytic activity at alkaline pH in which pH effective zone hydrolysis occurred. The results suggest that acrosomal proteinases in addition to acrosin may be involved in the zona penetration.
Stomatogenesis during sexual and asexual reproduction in an amicronucleate strain of Paramecium caudatum
Authors: Mikami Kazuyuki
Published: June 2005

Amicronucleate cells of Paramecium caudatum, whose micronuclei have been artifically removed by micropipetting, are characterized by the appearance of a deciliated area at the posterior part of the buccal opening. These cells form food vacuoles at a slightly lower rate than micronucleate cells. Their mean interfission time is longer than that in micronucleates. The exconjugants of amicronucleate cells can not form food vacuoles and eventually die without fission, though conjugation proceeds normally in them as well as in their micronucleate mate. The oral apparatus of amicronucleate exconjugants seems can be seen through the buccal overture by scanning electron microscope. The results obtained from the cross of micronucleate and amicronucleate strains and from the induction of autogamy in amicronucleate strains suggest that the micronucleus has a primary role in developing the normal oral apparatus after nuclear reorganization.
Effect of thyrotropin releasing factor on body weight of the pond snail Lymnaea stagnalis
Authors: Grimm‐Jørgensen Yvonne
Published: June 2005

Earlier studies had demonstrated that in Lymnaea stagnalis thyrotropin releasing factor (TRF) may be the secretory product of the so‐called dark green neurosecretory cells. The dark green cells are believed to serve an osmoregulatory function. If TRF is the secretory product of the dark green cells, it should be capable of controlling the salt and water balance in L. stagnaus. In this study, the effect and fate of synthetic TRF injected in vivo into L. stagnalis was assessed. It was found that TRF caused an increase in the rate of loss of body water which normally occurs after anaesthesia. TRF also increased the loss of body water when it was administered to unanaesthetized animals. The peptide was accumulated and degraded by the tissues of the foot, mantle, and head regions, tissues which are believed to be the targets of the hormone of the dark green cells. Our results support the hypothesis that TRF may be the secretory product of the dark green cells and may be involved in osmoregulation in L. stagnalis.
Abnormal scale morphogenesis: Relationship of polypeptide patterns to action of the scaleless gene
Authors: Mirkes P. E. , Sawyer R. H.
Published: June 2005

The polyacrylamide gradient gel electrophoresis (PAGGE) pattern of polypeptides isolated from normal scuttate scale epidermis of 1‐week‐old chicks was different from that of the anterior shank epidermis from 1‐week‐old scaleless mutant chicks. The PAGGE patterns of polypeptides isolated from normal and scaleless reticulate scale epidermis (from 1‐week‐old chicks) differed by only one band, whereas comparison of mutant's scuttate and reticulate patterns showed three band differences. These data are discussed in relation to the action of the scaleless gene on early morphogenesis of the two types of scales.
Progesterone induction of oocyte maturation in Rana pipiens: Reversibility of cycloheximide inhibition
Authors: Samson Douglas A. , Schuetz Allen W.
Published: June 2005

The reversibility of cycloheximide inhibition of progesteroneinduced oocyte maturation was investigated. Progesterone treated immature oocytes underwent nuclear (germinal vesicle breakdown) and cytoplasmic maturation unless inhibited by incubation in the continuous presence of cycloheximide. However, when previously treated oocytes were simply washed in culture media on the day following the initial treatment, they matured without additional exposure to progesterone. The incidence of germinal vesicle breakdown observed after washing and reincubation was similar to that seen in paired oocytes retreated with progesterone, cycloheximide‐pretreated control oocytes newly treated with progesterone or control oocytes treated only with progesterone on the first day. Oocytes exposed to low concentrations of progesterone matured the following day whereas paired oocytes inhibited by cycloheximide during the first day did not mature at similar low doses following washing on the second day. The time of germinal vesicle breakdown in oocytes previously inhibited with cycloheximide was either slightly delayed or unaltered as compared to that of control oocytes newly treated with progesterone. The results indicate that an initial step of progesterone induced maturation in Rana is reversibly blocked but not detrimentally altered by cycloheximide. The evidence suggests that the effects of cycloheximide may be mediated through effects on the formation and/or autocatalytic production of maturation promoting factor (MPF). The cellular and molecular significance of these data to the process of meiotic arrest and oocyte maturation are discussed.
Acrosome removal induces features analogous to fertilization during mouse sperm fusion with somatic cells
Authors: Široký Jiří , Spurná Věra , Kopečný Václav , Tkadleček Ludvík
Published: June 2005

Spontaneous and induced fusion of intact and acrosome removed spermatozoa with mouse fibroblasts (L cells) was studied in vitro.

In the experiments with acrosome‐removed spermatozoa some features similar to physiological fertilization were seen during the process of spontaneous heterokaryon (Hk) formation. Even in the initial stage of co‐incubation the treated spermatozoa generally adhered to the surface of somatic cells by the posterior region of the head. The penetration of acrosome‐removed spermatozoa to the cytoplasm of L cells then occurred but was markedly delayed. Penetration of L cells by non‐treated spermatozoa did not occur. The observed triggering of sperm chromation decondensation in the heterokaryon indicates a “true membrane reaction” during the process of fusion of acrosome‐removed spermatozoa and L cells.

The degree of sperm head decondensation remained incomplete in all cases detected and only 10−3 Hk contained decondensed chromatin of spermatozoal origin.

It is concluded that a true membrane reaction may be induced between spermatozoa and somatic cells, after acrosome destruction by simple physico‐chemical agents, and without “fusogenic” agents.
The fine structure of developing cartilage in the chick embryo
Authors: Olson Mark D. , Low Frank N.
Published: June 2005

The fine structure of developing cartilage is described in the area of the future vertebral bodies in the cervical region of chick embryos. Incubation ages range from 36 hours, when the schlerotome.
Nerve dependent macromolecular synthesis in the pectoral fin regenerate of the fish, Fundulus
Authors: Géraudie Jacqueline , Singer Marcus
Published: June 2005

Total resection of the brachial plexus of the regenerating pectoral fin in the fish Fundulus immediately affects protein and DNA synthesis. As in the case of nerve dependent synthesis in urodele limb regeneration, there is at first an outburst in macromolecular synthesis which peaks in the early hours after denervation. Then there is just as rapid a decline to a plateau value about 50–60% of its normal one at 24 to 48 hours after denervation. These data are discussed against the background of previous results from this laboratory on denervated newt limb regenerates.
Interactions between irradiated and unirradiated tissues during supernumerary limb formation in the newt
Authors: Holder Nigel , Bryant Susan V. , Tank Patrick W.
Published: June 2005

The interactions between irradiated and unirradiated blastemas and stumps in the newt forelimb were studied. Irradiated right blstemas at the stage of early digits were grafted to unirradiated left stumps and unirradiated left blastemas were grafted to irradiated right stumps. Grafts were oriented with their anterior‐posterior axes opposed to that of the stumps. Supernumerary limbs ranging in completeness from one to four digits were found to arise predominantly on the anterior or posterior sides of the host limb. The graft developed well when the blastema was unirradiated and had reversed handedness with respect to the stump. Irradiated grafts developed poorly. On occasions, limbs with two supernumerary structures were found. The results are discussed in terms of the origin of the cells which comprise the supernumerary limbs and their bearing on a recently presented model concerned with pattern specification and regulation in epimorphic fields.
DNA polymerase activity in preimplantation mouse embryos
Authors: Kiessling A. A. , Weitlauf H. M.
Published: June 2005

DNA polymerase activity was measured in mouse embryos at stages before implantation to determine whether it increases in proportion to the amount of DNA synthesis, as it does in populations of differentiated mammalian cells, or remains constant, as it does in early sea urchin embryos. Total enzyme activity was found to be relatively unchanged following fertilization and in the first few cleavage stages. However, between the 12‐ and 120‐cell (blastocyst) stage, the amount of activity increased by several‐fold. These results indicate that the relationship between amount of DNA polymerase activity and DNA synthesis in mouse embryos exhibits two phases: in the early cleavage phase it is similar to that in sea urchin embryos, whereas, in the blastocyst phase, it is similar to that in differentiated mammalian cells.
Surface contractile activity of the Tubifex egg: Its relationship to the meiotic apparatus functions
Authors: Shimizu Takashi
Published: June 2005

The dependence of surface contractile activity (deformatin movement: DM) on the meiotic process in the fertilized Tubifex egg was examined with colchicine and dinitrophenol (DNP). The normal DM occurred at the time of the formation of the first and second polar bodies, during which the egg shows groove‐forming activity on the surface of the animal hemisphere and the equatorial regions. Grooves invariably appeared first on the equatorial surface, then on the animal hemisphere. A scanning electron microscopic observation revealed that the surface deformation of the animal hemisphere began concurrently with the appearance of proximal constriction of the cytoplasmic bulge for the polar body.

DNP of 2.5 × 10−5 M did not disturb the meiotic process but inhibited equatorial grooving. The animal hemisphere grooving in these eggs took place on the same schedule as for normal eggs. The number of microfilaments per unit area of the egg surface apparently decreased after DNP‐ treatment; the organization of microfilaments in the cortical layer was more heavily influenced at the equaorial region than in the animal hemisphere. Colchicine of 4 × 10−3 M destroyed the meiotic apparatus and completely prevented the grooving of the animal hemisphere. The equatorial grooving proceeded normally in these colchicine‐treated eggs. From these results, it is strongly suggested that there are regional differences in the contractile mechanism of the egg surface and that the animal hemisphere grooving is closely related to the presence of the meiotic apparatus while the equatorial grooving is independent of it.
Antibodies against invertebrate actin: Their phylogenetic cross‐reactivity
Authors: Kleve Maurice G. , Fuseler John W. , Clark Wallis H.
Published: June 2005

Invertebrate muscle actin was extracted from penaeid shrimp tail muscle and purified by self‐assembly polymerization. Further purification for use as an antigen was accomplished by SDS polyacrylamide gel electrophoresis. Antibodies to highly purified shrimp tail muscle actin were produced in rabbits and were collected as an ammonium sulfate gamma globulin fraction from sera. These antibodies, which cross react with native actin, SDS denatured actin, and formalin fixed actin were successfully used to immunofluorescently label actin in cells. Actin in muscle and non‐muscle cell types from species of five invertebrate phyla and numerous species of vertebrates were labeled with no apparent difference in antibody specificity or sensitivity. These results suggest that the immune identity of the actin molecule is conserved over the span of the phylogenetic tree.
Pineal involvement in the control of circadian rhythmicity in the lake chub, Couesius plumbeus
Authors: Kavaliers Martin
Published: June 2005

Removal of the pineal organ from the lake chub, Couesius plumbeus, had significant effects on circadian locomotor activity. In fish kept in continuous darkness the absolute length of the circadian period was significantly altered; the variability of the period was increased; and ultradian rhythms were eliminated. These findings indicate that the pineal organ is involved in the control of circadian rhythmicity in this teleost fish.
Biochemical studies of the hatching process in sea urchin embryos. I. Effects of protease inhibitors
Authors: Hoshi Motonori , Moriya Tsuneo , Aoyagi Takaaki , Umezawa Hamao
Published: June 2005

Effects of 12 protease inhibitors both on the hatching process and on the activity of the hatching enzyme of the sea urchins, Hemicentrotus pulcherrimus and Strongylocentrotus intermedius, were studied. Synthetic inhibitors, N‐tosyl‐L‐phenylalanyl‐chloromethane (often called tosylphenylalanine chloromethylketone; TPCK), N‐α‐tosyl‐L‐lysyl‐chloromethane (often called tosyllysine chloromethylketone; TLCK), p‐nitrophenyl p'‐guanidinobenzoate (NPGB), diphenylcarbamyl chloride (DPCC) and phenylmethane sulfonyl fluoride (PMSF), caused cytolysis of embryos, whereas the microbial inhibitors, chymostatin, leupeptin, antipain, pepstatin, elastatinal and phosphoramidon, and soybean trypsin inhibitor did not. Among them, the inhibitors specific against chymotrypsmsy chymostatin and TPCK, delayed the hatching process and inhibited the hatching enzyme. NPGB also inhibited the enzyme but its effect on the hatching process was uncertain because of its general toxicity to embryos. Esterolytic hydrolysis of N‐acetyl‐L‐tyrosine ethyl ester (ATEE) by a crude preparation of the enzyme was found.

The evidence presented suggests that the hatching enzyme of sea urchins is similar to chyrmotrypsin.
Inhibition of desmosome formation in chick cell aggregates
Authors: Overton Jane
Published: June 2005

Desmosomes (macula adherens) have been associated with the function of adhesion. Their possible role in aggregation and sorting of chick and mouse epithelial cells has been investigated. Treatment of aggregates with 2–5 μg/ml of actinomycin D which inhibited RNA synthesis also inhibited both desmosome formation and aggregation if administered at the beginning of the aggregation process. In contrast, if the drug was administered at six hours, when the cells had recovered from the process of dissociation, then aggregation over the following six hours appeared normal from observation of living samples. Such aggregates incorporated leucine‐3H at roughly 85% of the control level. A quantitative comparison was made of desmosome formation in aggregates treated with actinomycin D for hours 6–12 and those cultured in normal medium. Desmosome formation was inhibited by the drug, although aggregation could proceed. Combinations of chick corneal and mouse skin cells sorted out in the presence of actinomycin D to the same extent as controls. Thus desmosome formation, which normally occurs during aggregation of the epithelial cells studied here, is not coupled with the aggregation or cell sorting process in these cells of stratified epithelia. When cells were treated with cycloheximide (100 μM) both desmosome formation and the progressive rounding up of aggregates was inhibited.
Evidence for a broadly‐specific, amino acid requiring dehydrogenase at the pyruvate branchpoint in sea anemones
Authors: Ellington W. Ross
Published: June 2005

The tissues of a number of species of sea anemones contain an enzyme(s) capable of oxidizing NADH in the presence of pyruvate and either L‐arginine or L‐alanine. The activities using either amino acid coelute on Sephadex G‐100 and DEAE‐Sephadex −50 columns. In addition, the peak DEAE‐Sephadex fractions utilize other amino acids including glycine, lysine and threonine. The above catalytic activities may be due to a single, broadly‐specific enzyme.
Some peripheral auditory characteristics of the marsupial brush‐tailed possum, Trichosurus vulpecula
Authors: Aitkin L. M. , Gates G. R. , Kenyon C. E.
Published: June 2005

Some anatomical and physiological aspects of the peripheral auditory system were examined in anesthetized brush‐tailed possums (Trichosurus vulpecula) and compared with those in the cat. Cochlear microphonic potentials (CM) in response to tones of varying frequency and intensity were recorded at the round window.

The cochlea of Trichosurus has a typically mammalian appearance, with three and one‐half turns and a basilar membrane approximately 17 mm in length upon which sit three rows of outer and one of inner hair cells. Three middle ear ossicles, including a delicate stapes of columelliform appearance, are housed in a cavity adjacent to a spongy mass of bone. The latter surrounds the round window and is quite unlike the bullae of many eutherian mammals.

Round window recordings revealed that CM potentials of the possum rarely attained magnitudes, for any tone, in excess of 500 μV and were always 10–25 dB less in amplitude than CM of the cat at a given frequency and intensity. The threshold intensities required to elicit a 50 μV CM at frequencies between 0.4 kHz and 10 kHz were smaller for the cat than the possum, but a slightly greater sensitivity was shown by the possum between 0.1 kHz and 0.4 kHz.

Peripheral auditory characteristics of the marsupial brush‐tailed possum thus appear to have some features in common, and others at variance, with commonly‐studied placental mammals.
Activity of the cortical ampules during the vegetative cycle of the ciliate Euplotes crassus
Authors: Rosati Giovanna , Verni Franco
Published: June 2005

The activity of cortical Ampules (As) was followed during the vegetative cycle of Euplotes crassus. The storage and release of As contents occur according to a well defined cycle which is correlated with the macronuclear phases.
Acute and chronic hypoxia in rats. II. Effect on oxidative phosphorylation and in vitro protein synthesis in liver mitochondria and its subpopulations
Authors: Pickett Cecil B. , Cascarano Joseph
Published: June 2005

The objective of this investigation was to examine liver mitochondrial functions in rats exposed to 0.4 atm for 0, 5 and 27 days. Liver homogenates were fractionated by rate‐zonal centrifugation utilizing iso‐osmotic Ficoll‐sucrose gradients; this eliminates loss of large and small mitochondria and makes possible the separation of mitochondria into subpopulations according to sedimentation coefficient. After pooling all mitochondrial fractions for obtaining composite determinations of the entire population, large diminutions in states 3 and 4 respiration (succinate as substrate) were obtained in day‐5 and day‐27 rats but no changes were evident with regard to ADP:O ratios, respiratory control indices or the capacity for in vitro protein synthesis. By examination of subpopulations of mitochondria, it was found that mitochondria are heterogeneous with regard to ADP:O ratios, respiratory control indices, states 3 and 4 respiration and the capacity for in vitro protein synthesis. The heterogeneity for each of these parameters was altered in day‐5 and day‐27 animals. Although states 3 and 4 respiration were depressed throughout the entire mitochondrial population for day‐5 and day‐27 rats, a subpopulation of mitochondria from day‐27 rats showed respiratory control indices and ADP:O ratios which were higher than any subpopulation of mitochondria of either day‐5 or day‐0 animals.
Interaction between normal and pigment cell populations mutant at the diominant‐spotting (W) and steel(Sl) loci in the mouse
Authors: Mayer Thomas C.
Published: June 2005

Through the use of dermal‐epidermal recombination methods a competition between mouse embryo melanoblasts of the genotype Wν/w C/C, w/w c/c, Sld/sl C/C and sl/sl c/c was established. Control combinations were made between C/C and c/c components. The extent of pigment found in hair of grafts after three weeks growth in mouse testes was used as evidence of an interac‐tion between populations. Normal and albino melanoblasts were found to be similar in viability, whereas melanoblasts of the genotype Wν/w C/C were largely excluded from hair follicles when placed in competition with w/w c/c melanoblasts. No difference in competitive advantage was observed between Sld/sl C/C and sl/sl c/c populations. These results confirm that the W and S1 loci act at different sites. In addition they suggest that Wν/w melanoblasts are marginally viable cells that cannot compete with normal melanoblasts when the populations interact. The Wν/w melanoblast failure can also explain the spotting pattern and pigment dilution characteristic of dominant‐spotting heterozygous mice.
Taurine maintains and stimulates motility of hamster sperm during capacitation in vitro
Authors: Mrsny Randall J. , Waxman Lloyd , Meizel Stanley
Published: June 2005

It is known that hamster sperm require an unidentified low molecular weight “factor” found in several cells and tissue types in order to remain strongly motile during in vitro capacitation. The β‐amino acid taurine (2‐aminoethane sulfonic acid) is present in a partially purified “factor” from bovine adrenal glands and can substitute for that “factor” in maintaining and stimulating hamster sperm motility. Incubation of washed hamster sperm with bovine serum albumin and 2 × 10−3 to 2 × 10−5M taurine for periods of approximately 5 hr. resulted in a higher number of strongly motile sperm compared to controls in the absence of exogenous taurine. Incubation of sperm with (‐)epinephrine in the absence of taurine resulted in nearly all sperm becoming immotile. Activation (whiplash flagellar movement characteristic of capacitated hamster sperm) did not occur in the absence of taurine, but high percentages of activation occurred in the presence of 2 × 10−3, 2−10−4 and 2 × 10−5M taurine. Acrosome reactions occurred in the presence of taurine, even in the absence of (‐)‐epinephrine. However, (‐)‐epinephrine, previously shown to stimulate activation and acrosome reactions, was required for the maximum number of the latter. These results suggest that in addition to its importance for motility taurine might stimulate capacitation. The mechanism through which taurine supports and stimulates motility is not yet known, but its use results in the first relatively “defined” in vitro capacitation medium for hamster sperm.
Reversal of polarity in ciliated cells of the isolated sea urchin pluteus gut
Authors: Amemiya Shonan , Akasaka Kohji , Terayama Hiroshi
Published: June 2005

Guts isolated from pluteus embryos of Hemicentrotus pulcherrimus were observed by scanning electron microscopy in the course of 24 h culturing in normal sea water. They showed marked morphological changes such as disappearance of the regional features, closure of the endings (oral and anal), and reappearance of the regional features corresponding to the stomach and esophagus (but lacking the intestinal and pharyngeal regions). In parallel to the above morphological changes, the cilia usually associated with the interior surface of isolated guts disappeared and new cilia appeared on the exterior surface of the isolated guts, causing the isolated guts swim around by the end of the culture period. These results suggest the reversion of cellular polarity in the isolated gut wall in response to the environmental change.
Osmotic and cell volume regulation in the goby, Gillichthys mirabilis
Authors: Loretz Christopher A.
Published: June 2005

The gobiid teleost Gillichthys mirabilis acclimated successfully to external environments ranging from 100% seawater to freshwater. Plasma composition and cell volume are regulated in both hypo‐ and hyperosmotic environments. Significant declines in plasma electrolyte concentrations and increase in intracellular hydration were observed only in freshwater‐acclimated fish. Cell volume regulation in hypoosmotic media appears to result from the loss of intracellular solutes. Hypophysectomy seriously impaired regulation of plasma composition and cell volume in dilute external environments, a finding consistent with the known role of prolactin in promoting freshwater survival of teleosts.
Ecdysteroid levels and pupariation in drosophila melanogaster
Authors: Berreur P. , Porcheron P. , Berreur‐Bonnenfant J. , Simpson P.
Published: June 2005

Ecdysteroid titers measured in the haemolymph of third instar larvae of Drosophila revealed the existence of a small peak (40 ng/ml) preceding the major peak at pupariation. Under experimental conditions of delayed pupariation, the release of both ecdysteroid peaks is retarded. The possibility that the earlier pulse is implicated in the programming of the time of pupariation is raised.