bluuebunny/crossref_metadata_2025_split huggingface dataset:
Trout intestinal alkaline phosphatases. II. The effect of temperature upon enzymatic activity in vitro and in vivo
Authors: Whitmore Donald H. , Goldberg Erwin 
Published: June 2005

AbstractTwo fundamental physical properties of partially purified trout intestinal alkaline phosphatases which have been examined in detail are thermostability and activation energy. It has been clearly demonstrated that differences in thermostability exist between the trout isozymes, and that as a group they are more thermolabile than mammalian phosphatases. The activation energies of the two main trout phosphatase zones, however, are comparable to mammalian phosphatases.Experiments on cold‐acclimation of hatchery brook trout suggest that a fundamental reorganization of the intestinal alkaline phosphatase complement occurs. There are drastic quantitative differences in the isozyme patterns of 4° C‐acclimated fish and those acclimated to 10° C or 15° C. The 4° isozyme complement has a lower activation energy in the range of 2° C−10° C than does the 10° C isozyme complement. This finding strongly suggests that there is a reconstruction of the phosphatase isozyme complement with cold‐acclimation. This is functionally significant in that it results in the production of enzymes better suited to the new thermal regime. Three mechanisms are discussed as possible regulators of this process.
Experimental demonstration of holokinetic chromosomes, and of differential “radiosensitivity” during oogenesis, in the grass mite, Siteroptes graminum (Reuter)
Authors: Cooper Ruth S. 
Published: June 2005

AbstractEarly cleavage stages, mature eggs and developing oocytes of the grass mite Siteroptes graminum (Reuter), formerly Pediculopsis graminum (Reuter), (2n = 6; males haploid), were irradiated to: (a) test the hypothesis that the chromosomes are not monokinetic, (b) determine whether the chromosomes respond differently to irradiation during oogenesis and cleavage, and (c) find out whether a special region on the chromosome is required for elaboration of its chromosomoid (Feulgen‐negative body otherwise resembling the chromosome) which is left on the equator during both the meiotic and early cleavage mitoses. Fixation occurred 1–27 hours after irradiation.Chromosomal complements of more than 160 embryos (egg through 128 cell), and a few meiotic figures, were analyzed. Clusters of cells with decipherable chromosomal complements of 8–16 elements occurred frequently, and in especially favorable embryos karyotypes of all or nearly all the blastomeres could be analyzed. Many chromosomal fragments passed through at least three to five cleavage divisions in normal or nearly normal manner. Fragments which had come through one or both meiotic divisions behaved in blastomeres in a manner similar to those induced in cleavage stages. The chromosomes, therefore, are holo‐ or polykinetic in the classical sense. The tiniest fragments and very large translocations, however, tended to missegregate or to be eliminated.Some fragments were observed en route to or at the poles in both meiotic divisions. However, aberrancies in chromosomal behavior were more frequent during the maturation divisions, especially anaphase and telophase I, than during cleavage mitoses.Differential radiosensitivity was detected during the course of oogenesis, and between oogenesis and cleavage stages, the first known case in the class Arachnida. As earlier stages were irradiated, there was a trend in blastomeres toward fewer fragments, and far more normal and nearly normal karyotypes. Irradiation of cleavage stages yielded most fragments. Probable causes of this differential radiosensitivity are discussed.In the few cases with well‐preserved, discrete chromosomoids the relative size of the chromosomoid and its associated chromosomal elements (including very small fragments) were correlated, and in several cases more than the diploid number of each was present. This suggests, but does not prove, that any part of the chromosome can elaborate chromosomoidal material.Possible causes, other than restriction of the kinetochore, for aberrancies in chromosomal behavior during both somatic and meiotic mitoses are discussed. The more recent literature on holokinetic chromosomes is analyzed, and new speculations about differences between mono‐ and holokinetic chromosomes are made. Factors of importance in design of experiments to determine the location of kinetochores are discussed.
Inhibition of imaginal differentiation in Sarcophaga bullata by juvenile hormone
Authors: Bhaskaran G. 
Published: June 2005

AbstractThe effects of DL‐juvenile hormone on imaginal differentiation in Sarcophaga bullata were studied with particular reference to the tissues of the abdomen. The hormone was applied topically on the pupal cuticle at the time of eversion of the head. The development of the abdomen varied considerably but a majority of the animals showed morphological abnormalities and none emerged. Histological examination of the treated animals at different periods of adult development revealed that none of them had secreted a second pupal cuticle. The most severe morphogenetic effect observed was the inhibition of the spreading of the histoblast cells. Consequently the imaginal epidermis was not formed and cuticular structures xwere completely absent. The differential sensitivity of the various cell groups derived from the histoblasts and the genital disc to JH were reflected in their developmental behaviour and are described in detail. The most conspicuous cellular effect, however, appears to be the inhibition of differentiation. Hence the JH induced abnormalities show striking similarities to those induced by x‐irradiation as well as other inhibitory agents during the metamorphosis of higher Diptera and are probably related to the highly determinate state of the cells.
Isozyme patterns of lactate dehydrogenase, creatine phosphokinase, phosphoglucomutase and aldolase of guinea pig tissues during ontogeny
Authors: Prochazka B. , Wachsmuth E. D. 
Published: June 2005

AbstractQuantitative changes in the isozyme patterns of lactate dehydrogenase, creatine phosphokinase, phosphoglucomutase and aldolase during the ontogeny of guinea pig heart muscle, skeletal muscle, kidney and liver were investigated simultaneously.In nearly all organs these changes could be attributed to the increase of that subunit which was predominant in the adult tissue. The adult isozyme patterns of PGM and CPK appeared earlier than those of ALD and LDH.The findings that the distributions are different for different isozymes, different tissues and different stages of development are discussed.
The role of antlers in the behaviour of red deer
Authors: Lincoln G. A. 
Published: June 2005

AbstractThe behaviour of red deer stags following antler casting, antler breakage, antler amputation and antler stunting was studied to establish the ways in which antlers normally function. It was found that after the loss of antlers, either naturally or artificially, individuals became less effective in competition with other stags, resulting in loss of social rank in the bachelor group and failure to secure hinds in the rut.The observations indicate that antlers normally function as a weapon and guard in conflict between stags and allow animals to lock their heads together for fighting. Of equal importance is the visual effect of the antlers denoting status of the individual, allowing for domination without physical force. While the stags are living in the bachelor herds the antlers appear to be the principal status symbol. During the rutting season, additional display symbols and characteristics come into use, and it is the significance of these in intimidation which allows stags without antlers (hummels) to be successful in the rut. There is slight evidence to support the idea that the antlers function in attracting hinds.
In vitro uptake and incorporation of amino acids by blastocysts from intact and ovariectomized mice
Authors: Weitlauf Harry M. 
Published: June 2005

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

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

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

AbstractThe embryological development of the eggs laid by the sex‐linked recessive female‐sterile mutant almondex (amx) of Drosophila melanogaster has been analyzed by use of both living and sectioned material.The mating amx ♀ × amx ♂ is lethal to all embryos. Advanced but abnormal development occurs. Development is normal until shortly after the time of maximal germ band extension. The principal anomalies involve derivatives of the ectoderm and somatic mesoderm; both dorsal closure and head involution are impaired.The mating amx ♀ × non‐amx (+) ♂ produces a similar pattern of damage in male (amx/Y) embryos, none of which hatch. In female (amx/+) embryos, however, there is an amelioration of development, although the pattern of damage is still so severe that most embryos succumb. A few female offspring and occasional non‐disjunctional non‐mutant (XO) male offspring survive to the adult stage; these adult progeny frequently have defects of the thorax and abdominal sternites.These results can be explained by assuming that the cytoplasm of eggs produced by amx females is deficient for some material that is necessary for normal development. It is suggested that either an inherent structural defect in the presumptive ectoderm or some metabolic defect to which the ectoderm is particularly susceptible may underlie the morphological defects found in the progeny from amx females.
An analysis of urodelian retinal regeneration: I. Studies of the cellular source of retinal regeneration in Notophthalmus viridescens utilizing 3H‐thymidine and colchicine
Authors: Keefe J. Richard 
Published: June 2005

AbstractThe process of retinal degeneration and regeneration in retinectomized or enucleated and reimplanted eyes of adult Notophthalmus viridescens has been studied following staged administrations of tritiated thymidine or colchicine. In control left eyes, no labeled cells were observed in either the retina, pigment epithelium, or ora serrata. In retinectomized or enucleated eyes, retinal degeneration proceeded from the posterior central pole circumferentially to the ora serrata, with complete retinal degeneration being consistently observed. Retinal replacement originated from two cellular sources: the posterior pigment epithelium and the anterior complex, consisting of cells in the ora serrata and pars ciliaris retina.The posterior pigment epithelium gave rise to an initial central retinal portion which differentiated in an annular pattern which extended from the optic nerve to the vortex veins. Cellular addition from the pigment epithelium became restricted to these two regions by day 25. The anterior retinal mass was regenerated from the anterior elements (ora serrata/pars ciliaris retina) with a minor contribution from the underlying anterior pigment epithelium. Data concerning the relative numbers of cellular types involved in the regenerative sequence and the times of their function are presented. Peak labeling occurred in the posterior pigment epithelium at day 20, the pars ciliaris retina at days 18 and 40, and the new retina at days 28 and 41. By 30 days regional sites of cellular proliferation became established that coincided with the pattern of ocular blood vessels. Retinal differentiation followed the pattern commonly observed during retinal development.The significance of these observations with respect to earlier work demonstrating a different sequence for retinal restoration is discussed.
An analysis of urodelian retinal regeneration: II. Ultrastructural features of retinal regeneration in Notophthalmus viridescens
Authors: Keefe J. Richard 
Published: June 2005

AbstractThe process of retinal regeneration in the posterior pole of enucleated and reimplanted eyes of adult Notophthalmus viridescens was studied with the electron microscope. The posterior pigment epithelium displayed two distinct cellular types which served either as phagocytic cells or for repopulating the retina. The phagocytic cells, which displayed a marginal nuclear chromatin, numerous mitochondria and profiles of rough endoplasmic reticulum, served to remove degenerating retinal and lens debris. The cells destined to repopulate the retina appeared to pass through an indifferent phase in which both single melanin granules and sequestered areas of pigmented cytoplasm were extruded. These cells displayed a markedly heterochromatic nucleus surrounded by a cytoplasm with scattered free ribosomes, short profiles of endoplasmic reticulum, and small rounded mitochondria. Once the retinal regenerate has been formed, the pigment epithelium was restored upon Bruch's membrane and the cells displayed melanin formation and an extensive smooth endoplasmic reticulum. The development of the full melanin complement, with apical cytoplasmic fringes and rough endoplasmic reticulum, depended upon differentiation of the new retina.By day 25, the newly reconstituted retina began to display vertical alignment of cells and differentiation of the inner layers. Each of the photoreceptors passed through an indifferent phase in which all cells showed a similar mitochondrial ellipsoid and small glycogen paraboloid. Rods, due to their increase in size, and double cones, due to the encapsulation of the principal element within the accessory element, were the first photoreceptors to become recognizable. The initial formation of the outer plexiform layer resulted from an outgrowth of horizontal cell processes coincident with a wave of local cellular degeneration. Synaptic bases of the photoreceptors developed fully after invagination by the principal bipolar and horizontal processes.The significance of the cellular patterns observed during retinal restitution and differentiation, with respect to the origin of the double cone and the formation of rods and cones, and the nature of the pigment epithelial cells and their response to local degeneration of the retina, is discussed.
Effects of temperature on the ultrastructure of severed crayfish motor axons
Authors: Nordlander Ruth H. , Singer Marcus 
Published: June 2005

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

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

AbstractAnthias squamipinnis (Anthiidae, Teleostei), a sexually dimorphic coral fish, is found in large swarms along the western coast of the Gulf of Aqaba. Each swarm is permanently bound to a particular rock or coral head. During daytime, the fish stay close to their coral head and spend the night in holes and crevices in the rock.Some of the males are territorial, defending water spaces near the rock, performing special displays and chasing away male intruders. The nonterritorial males swim in separate swarms closer to the bottom. A third part of the population consists of females and young that swim above the swarm of nonterritorial males. These last two groups form the main mass of the population and are spread out rheotactically in front of the rock, feeding on the plankton carried by the current.Spawning is carried out in the evening from November to June. It is preceded by a precopulatory “dance” initiated by the territorial males and joined by the females and nonterritorial males. The eggs are planktonic.Sexual inversion was observed in many specimens in nature and in captivity. After a period of about one year, functional females gradually change coloration and switch into functional males. They may join either the swarm of nonterritorial males or the group of territorial males.