bluuebunny/crossref_metadata_2025_split huggingface dataset:
L(+)‐lactate dehydrogenases from Hymenolepis diminuta (Cestoda)
Authors: Walkey Michael , Fairbairn Donald 
Published: June 2005

AbstractProperties of L( + )‐lactate dehydrogenases from infective eggs, cysticercoids, immature proglottids (anteriors), and pre‐patent (seven day) infections of H. diminuta were studied. Fractionation of isozymes by disc gel and cellulose acetate electrophoresis was unsatisfactory, but some fractionation was obtained by electrofocusing. Other evidence suggested that one form of LDH predominated in eggs and cysticercoids, and a second form in anteriors and pre‐patent worms. The first form was relatively resistant to thermal inactivation and was only slightly inhibited by pyruvate. The second resembled LDH−1 of mammals in being strongly inhibited by pyruvate, even though it occurred in life cycle stages that require no oxygen for grbwth and differentiation. In all tissues Km (lactate) was about 50–100 × Km (pyruvate), but Km (pyruvate) was much higher in eggs and cysticercoids (2.8 × 10−4) than in anteriors and pre‐patent worms (2.8 × 10−5 mole/li). Energies of activation were 8,419, 13,870, 16,107, and 22,633 cal/mole in cysticercoids, eggs, pre‐patent worms, and anteriors, respectively. In eggs and cysticercoids Km (pyruvate) passed through a minimum at 20−25°C, suggesting that LDH in these tissues may function efficiently at normal environmental temperatures. Anteriors and pre‐patent worms did not exhibit such a correlation.
Unscheduled synthesis of DNA during mammalian spermatogenesis in response to UV irradiation
Authors: Gledhill Barton L. , Darżynkiewicz Zbigniew 
Published: June 2005

AbstractUnscheduled incorporation of tritium‐labeled thymidine into nuclear DNA, induced by UV irradiation and presumed to indicate DNA repair replication, has been followed in differentiating male germ cells of the rat and rabbit by quantitative autoradiographic techniques. Cells at various stages of differentiation incorporated [3H] thymidine at different rates. The maximal rate was observed in nuclei of pachytene primary spermatocytes; the rate was markedly lower in spermatogonia and in leptotene and zygotene primary spermatocyte nuclei. No evidence of incorporation was found for nuclei of spermatids and testis spermatozoa.
Normal embryonic stages for salmonid fishes, based on Salmo gairdneri Richardson and Salvelinus fontinalis (Mitchill)
Authors: Ballard William W. 
Published: June 2005

AbstractAs a byproduct of a re‐examination of teleost morphogenetic movements, 23 stages in the normal development of salmonid fishes are presented, from fertilization to and beyond hatching, together with rates of their appearance at several constant temperatures. To aid in planning experiments, the period before closure of the germ ring is divided into 13 stages, with detailed discussion of internal structures and movements as well as external features, especially during gastrulation. The literature of salmonid development suggests that the stages are closely applicable to the embryos of any genera of Suborder Salmonoidei. except as to the rates of their appearance. Illustrations are designed for ready identification of stages. Tofacilitate their correlation with the older morphological literature, the principal events of organogenesis in the ectodermal, mesodermal, and endodermal categories are listed according to the stages at which they occur, as determined by dissections and serial sections.
An analysis of urodelian retinal regeneration: IV. Studies of the cellular source of retinal regeneration in Triturus cristatus carnifex using 3H‐thymidine
Authors: Keefe J. Richard 
Published: June 2005

AbstractThe process of retinal regeneration in adult Triturus cristatus carnifex was analyzed autoradiographically following tritiated thymidine administration at closely spaced postoperative intervals. In unoperated control animals given five daily doses of labeled thymidine, a continuous input of two types of cells was observed from the ora serrata into the ganglion cell and inner nuclear layers. One cell type appeared to represent retinal neurons with dispersed nuclear chromatin while the second cell type, containing a nucleus with dense heterochromatic rim, was displaced into all retinal layers with time, ultimately appearing within the layer of photoreceptor outer segments approximating the pigment epithelium. In operated animals, both control and operated (enucleated) eyes showed a loss of proliferative capacity from the ora serrata by two days postoperative.Retinal degeneration and regeneration in this species differed from that observed earlier for Notophthalmus viridescens in that: (1) invading pigment epithelia dissected the degenerating retina sequestering the outer nuclear layer between two epithelial sheets for phagocytosis by day 8; (2) degenerating inner retinal cells demonstrated labeling with thymidine and mitotic division before degeneration; (3) the process of removal of retinal and lens debris was assisted by vascularly derived phagocytes. The restoration of the retina involves both cellular addition from the anterior pars ciliaris retina and ora serrata, forming the anterior half of the new retina, and the posterior pigment epithelium, forming the posterior half of the retina from the innermost lamina. Sites of regional cellular proliferation at the vortex veins do not develop in this species. The basal pigment epithelium, upon Bruch's membrane, does not contribute to the retinal regenerate.The species differences presented in the process of retinal regeneration and the implications for the understanding of the generation of retinotectal specificity are discussed. It is concluded that the specificity engendered during both development and regeneration in this system must: (1) be derived from the ganglion cells; (2) be responsible for not only tectal connections but intra‐retinal position and connectivity; and, (3) not be temporally related.
The effects of aging on in vitro fertilization of rabbit eggs and subsequent embryonic development
Authors: Fraser Lynn R. , Dandekar Pramila V. 
Published: June 2005

AbstractRabbit eggs, with or without folliculai cells, are highly fertilizable in vitro (Fraser et al., »71). In vitro aging of intact, cumulus‐devoid, and corona‐devoid rabbit eggs did not appreciably lower their subsequent fertilizability in vitro with fresh sperm. The intact and cumulus‐devoid eggs were somewhat less fertilizable than the corona‐devoid eggs when aged for two and one‐half hours (70%, 68%, 91%, respectively), but this difference disappeared when the aging period was six hours (83%, 82%, 91%) or 12 hours (83%, 81%, 82%). Chromosome complements ranged from hypodiploid to polyploid in all groups, regardless of time of aging. Viability of embryos from the three groups, as determined by continued cleavage in vitro, was much reduced when compared to that of unaged eggs similarly cultured. There was no observable correlation between ploidy and development in culture; polyploid complements, particularly triploids, were found in both advanced and retarded stages.The possible effect of aging at an earlier time was noted in studies involving transfer of two to four cell embryos to pseudopregnant recipients. Embryos derived from eggs recovered 13 hours post‐LH and fertilized in vitro had low implantation rates and none of the implants developed to full term fetuses. However, the development of embryos from eggs recovered 12 hours post‐LH was not significantly different from embryos fertilized in vivo and cultured prior to transfer; 21% and 24%, respectively, of the embryos transferred developed to term.A number of the offspring have been raised to maturity. Those from the in vivo fertilized embryos have appeared normal and their eggs and sperm have had no obvious defects. From a similar sample size of in vitro fertilized offspring, 2/14 have displayed defects of the limbs resembling a condition termed splayleg, thought to be a recessive genetic trait. Whether conditions of in vitro fertilization might favor the union of two gametes carrying the recessive gene is not known.
Nucleotide phosphatase in Strongylocentrotus purpuratus eggs. II. Reactivation, substrate specificity, activators, and inhibitors
Authors: Schmidt Waldemar A. 
Published: June 2005

AbstractA medullary nucleotide phosphatase activity can be demon‐strated in fixed mature S. purpuratus eggs. However, this enzymatic activity is lost from eggs stored for more than four days in a Michaelis buffer prepared in distilled water. The activity can be reinstituted by overnight incubation in sea water or solutions of its major cations, prior to reacting for enzymatic activity.The substrate characteristics of this nucleotide phosphatase system indicate that the activity is not due to nonspecific acid or alkaline phosphatases, organic or inorganic pyrophosphatases, or hexose phosphatases. The activity is present with ATP and other nucleoside tri‐, di‐, and monophosphates and is most accurately labelled as a nucleotide phosphatase.The effects of various selected enzymatic activators and inhibitors upon the nucleotide phosphatase activity, demonstrated with ATP as substrate, are also presented. This activity is inhibited by L‐cysteine, glutathione, sodium fluoride, sodium tartrate, and zinc chloride; not inhibited by p‐chloromercuribenzoic and mersalyl acids; and stimulated by 2,4‐dinitrophenol, sodium azide, iodo‐acetamide, and ouabain. These data indicate some similarities with other phosphatases, but there are discriminating differences which label the enzyme system as a distinct entity.
Nucleotide phosphatase in Strongylocentrotus purpuratus eggs. III. Multiple enzymatic activities in mature and immature eggs
Authors: Schmidt Waldemar A. 
Published: June 2005

AbstractOn the basis of reaction patterns of eggs treated with activators and inhibitors and selected reactivating agents, there are at least three separate nucleotide phosphatase activities identifiable in maturing sea urchin eggs. Of these activities, the first two are sensitive to K + and Mg + +, respectively. The third activity is enhanced by both Na + and Ca + + and may represent two separate enzymes. These enzymatic activities are associated with different localizations and lead to a hypothesis of changing enzymatic patterns and localizations during the course of oogenesis.
The formation of the feeding organelle in Paramecium aurelia
Authors: Hanson Earl D. , Ungerleider Ross M. 
Published: June 2005

AbstractThe control of formation of the feeding or buccal structures in Paramecium aurelia has been studied by damaging or eliminating this organelle by means of a microbeam of ultraviolet light and following the fate of treated cells through subsequent fissions and autogamy. Homopolar doublets, with two sets of buccal parts per cell, provided one set as a control and to feed the cell while the other was used experimentally. The evidence shows that buccal morphogenesis is not simply self‐assembly of gene products but depends also on pre‐existing cytoplasmic differentiations of the cell.
Characteristics of hairs and related mechanoreceptors in the mouse and rabbit
Authors: Straile William E. , Mann Stanley J. 
Published: June 2005

AbstractCertain distinctive forms of hair act as levers for specific tactile receptors. Thus, information about hair structure can be used to locate and compare receptors among species and among different body areas. For example, the tylotrichs and bristles in both mice and rabbits activate special groups of receptors in the dermis, and the tylotrichs also displace innervated Merkel cells in the epidermis. Each of these hairs has definite structural features, which include a long graduated tip and wide shaft. This basic form characterizes all of the tylotrichs or bristles that grow in succession within a single follicle and related nerve cylinder during the life‐span of an animal. Most of the other hairs in mice have short tips and have narrow shafts with one or more constrictions. A short‐tipped hair with one constriction as well as a hair with three constrictions can grow through the same follicle and nerve cylinder in different hair growth cycles. Variations in hair constrictions probably have no bearing on receptor identification but must be investigated and thus eliminated as sources of confusion. There are more constrictions in first‐generation hairs than in the hairs formed in subsequent growth cycles. First‐generation hairs activate densely distributed receptors in a thin juvenile integument, whereas the less constricted hairs in adult animals activate receptors that are widely separated in a thick, fully expanded integument.
Specialized lactate dehydrogenase isozymes: The molecular and genetic basis for the unique eye and liver LDHS of teleost fishes
Authors: Shaklee James B. , Kepes Kathryn L. , Whitt Gregory S. 
Published: June 2005

AbstractElectrophoretic and immunochemical analysis of the lactate dehydrogenase isozyme patterns of fishes indicates that these isozymes are the tetrameric products of three LDH loci — A, B, and C — which are present in virtually all teleost fishes. The A and B genes of fishes and their corresponding isozymes have previously been shown to be homologous to the A and B genes of other vertebrates. The eye‐band LDH characteristic of many groups of teleosts, and the liver‐band LDH of gadoid and cyprinid fishes are shown in this report to be encoded in the same LDH locus, designated C. In different groups of fishes this third LDH gene (C) is extremely varied both with regard to its tissue‐specific regulation and with regard to the physical properties of its corresponding subunit. The electrophoretic mobility of the C4 isozyme ranges from highly anodal in some species to slightly cathodal in others while the mobilities of the A4 and B4 tetramers remain relatively constant. Most fish species express the A and B genes for LDH in nearly all tissues. In contrast, the C gene is highly restricted in tissue expression in most advanced teleosts where its isozymic products are found predominantly in the eye of some species or in the liver of others.
Adrenocorticosteroid levels in adult Diemictylus viridescens plasma following hypophysectomy and forelimb amputation
Authors: Liversage Richard A. , Price Brian W. 
Published: June 2005

AbstractThe relative levels of plasma adrenocorticosteroids in control regenerate, sham hypophysectomized and hypophysectomized adult male and female Diemictylus viridescens (common newt) were measured ten days after forelimb amputation and compared with those of intact animals.Our data provide evidence for an anterior pituitary‐adrenocortical axis in this urodele since hypophysectomy was followed by an appreciable decrease in the levels of plasma corticoids (corticosterone + cortisol) compared to control, sham and intact newts. The data also indicate that plasma adrenocorticos‐teroids are not abolished ten days post‐hypophysectomy. Corticosterone is the major adrenocortical steroid hormone in the plasma of this species.In the presence of markedly reduced titres of adrenocorticosteroids, our experimental newts were in an abnormal physiological state and exhibited typical non‐regenerating forelimbs ten days after concomitant hypophysectomy and amputation.
Functional development of the hypothalamo‐hypophyseal‐adrenal cortex axis in the chick embryo, Gallus domesticus
Authors: Wise Phyllis M. , Frye B. E. 
Published: June 2005

AbstractBasal plasma levels of corticosterone increased gradually during the second half of incubation, reaching a peak around the time of hatching. Stress resulted in a very significant elevation of corticosterone above the basal level in embryos 16 days or older, but not in younger embryos. Newly hatched chicks did not respond to stress, but a typical stress response was evident one week after hatching. Adrenocorticotropin (100 mU) elicited a significant rise in plasma corticosterone in 14‐day embryos and in newly hatched chicks, demonstrating that the adrenal is capable of responding to pituitary stimulation at these times when a stress response does not occur.Decapitated 16‐day embryos had significantly lower basal levels of corticosterone than normal, and showed no rise in corticosterone in response to stress. Basal levels of corticosterone were unaffected by decapitation of 14‐day embryos. Grafting ten‐day embryonic pituitaries to the chorioallantoic membrane on day 9 of incubation restored normal basal hormone levels on day 16 in decapitated embryos, but did not restore the ability to respond to stress.This study demonstrates that the hypothalamo‐hypophyseal‐adrenal axis is functional before hatching in chicks. The adrenal exhibits significant autonomous functional capability prior to day 14, and the pituitary becomes important in maintaining both the resting level of hormone and the stress response between days 14 and 16 of incubation. The hypothalamus does not appear to control normal resting levels of corticosterone, but is essential for the stress response.
Studies on hydra cells in vitro
Authors: Trenkner Ekkhart , Flick Kristine , Hansmann Gerald , Bode Hans , Bode Patricia 
Published: June 2005

AbstractMethods for the disaggregation of hydra and maintenance of hydra cells are described. The cells synthesize DNA, RNA and Protein linearly for about 16 to 24 hours. DNA synthesized by cells in vitro has the same buoyant density in CsCl as DNA synthesized in the animal. The size distribution and processing of RNA synthesized in cultured cells is similar to that in the whole animal. Conversion of large RNA molecules to 28S and 18S rRNA species occurs in cultured cells. Interstitial cells committed to nematoblast differentiation complete development of the nematocyst in vitro.
Effect of pinealectomy and photoperiodism in the reproduction of indian weaver birds, Ploceus philippinus
Authors: Balasubramanian K. S. , Saxena R. N. 
Published: June 2005

AbstractIndian weaver birds, Ploceus philippinus, are seasonal breeders and breed during June to August. Exposure of the adult male birds to long photoperiod (18L‐6D) during their nonbreeding period (November‐December), causes gonadal development and external changes (plumage and bill colour) characteristic of the breeding season, to occur a few months earlier than normal. Pinealectomy in winter also caused precocious sexual recrudescence. A combination of pinealectomy and long photoperiod accelerated the onset of the reproductive state more than either treatment alone. A short photoperiod (9L‐15D) which is normally nonstimulatory becomes stimulatory in pinealectomised birds which go into the breeding phase under this photoperiod within a few months of constant exposure.In the juvenile birds, which normally start breeding in the second year of life, precocious gonadal development and breeding can be induced by exposure to long day length and/or pinealectomy when they are only one year old. It seems that pineal in these birds inhibits early gonadal growth in the adults and delays the onset of puberty in juveniles under natural day length.
Lens differentiation from the cornea following lens extirpation or cornea transplantation in Xenopus laevis
Authors: Waggoner Phillip R. 
Published: June 2005

AbstractLarvae of Xenopus laevis at stage 46 or 50 were lentectomized and then fixed at various time intervals after the operation. Serial sections through the eye region were stained with hematoxylin and eosin or by the Himes‐Moriber technique to follow the histological changes taking place and to demonstrate any alterations in the basement membrane of the outer cornea. Lenses were observed to regenerate from the outer cornea while the basement membrane contributed to the capsule of the developing lens. A small lens with primary and secondary fibers was usually present by ten days after lentectomy.Corneas of Xenopus laevis larvae were implanted into lentectomized eyes, dorsal fins, amputated hindlimbs or subcutaneously in the head region. Lenses formed from the implants in the lentectomized eyes and in the amputated hind‐limbs, but no lenses developed in the dorsal fins or from the subcutaneous implants. It is hypothesized that some conditions in the environment of the lentectomized eye and the amputated hindlimb may be similar.
Aspects of adrenal function in neonatally estrogenized male mice
Authors: Simmons J. Emmett , DiClementi David , Maxted George 
Published: June 2005

AbstractNeonatal injection (day 5) of male CF1 mice with 50 μg of estradiol undecylate resulted in decreased body and testes weight and adrenal hypertrophy when these animals were examined at 95 days of age. The adrenal hypertrophy was associated with an increase in adrenal total cholesterol and plasma corticosterone after maximal ACTH stimulation. Orchiectomy of estradiol‐injected or oil‐injected control males did not significantly modify their response to ACTH stimulation. It is concluded that neonatal estrogenization of male mice causes, in addition to previously reported defects in subsequent reproductive function, long‐lasting changes in adrenal function.
Changes in liver metabolites during forelimb regeneration in the adult newt, D. viridescens
Authors: Procaccini Donald J. , Doyle Catherine M. , Procaccini Robert L. 
Published: June 2005

AbstractQuantitative extraction, histological, and histochemical procedures were used to investigate the effects of the stress of forelimb amputation on liver metabolites in the adult newt, D. viridescens. Results of these experiments showed that hepatic PAS responsive stores were depleted two hours through one week after amputation while protein decreased 24 hours — one week after amputation. There was no change in hepatic lipid. Hepatic GLU 6‐PDH and α‐glucan phosphorylase activities increased almost immediately after limb amputation and did not return to normal until one week and two weeks later, respectively. These and previous experiments suggest a systemic response to forelimb amputation whereby liver metabolites may initially provide energy reserves for escape and survival and then contribute to the early phases of regeneration.
Tissue distribution and properties of the lactate and supernatant Malate dehydrogenase isozymes of the grayling, Thymallus arcticus (Pallas)
Authors: Massaro Edward J. 
Published: June 2005

AbstractBy gel exclusion chromatography the molecular weight of T. arcticus LDH was estimated to be 135,000–140,000 and that of MDH to be 65,000–70,000. Employing electrophoretic mobility in starch gel, molecular hybridization, and immunoprecipitation, the LDH isozymes could be classified into three major groups designated a, b and c and a minor group designated β. The c group was found exclusively in the eye. All tissues examined contained a, b and c group isozymes. The interaction of skeletal muscle a‐group isozymes with rabbit anti‐weak fish (Cynoscion regalis) A4 LDH antiserum was weak and, therefore, similar to that of the group of isozymes of Prosobium cylindraceum previously designated f (Massaro, '72). Starch gel electrophoresis at pH 8.6 resolved three major isozymes of supernatant MDH. In skeletal muscle, two additional minor, weakly detectable isozymes were observed. These exhibited a greater net negative charge than the major isozymes and may be conformational isozymes.