bluuebunny/crossref_metadata_2025_split huggingface dataset:
Creatine kinase isozymes in pipid frogs: Their genetic bases, gene expressional differences, and evolutionary implications
Authors: Wolff J. , Kobel H. R. 
Published: June 2005

AbstractPipid frogs possess a creatine kinase isozyme repertory with a complexity paralleled only by teleostean fish. The effects of allelic polymorphism on their isozymes as well their differential solubility and resistance to heat denaturation suggest that species of Xenopus have at least four different CK loci. Each locus has its own tissue pattern of expression. CK‐I isozymes are found only in the eye and stomach of Xenopus, in the stomach but not the eyes of Pipa and Hymenochirus, and the latter appears to have this isozyme in the liver also. The tissue expression of CK‐II and CK‐IV, respectively, resembles that of CK‐A and CK‐C of fish and that of CK‐M (muscle) and CK‐B (brain) of higher vertebrates. CK‐III shows a striking developmental transition. In Xenopus heart muscle, additional CK isozymes are present that do not appear to be heterodimers. These may represent the contributions of additional creatine kinase genes or of epigenetic modification of other isozymes.The general tissue patterns of isozyme expression are similar but unique for each Xenopus species. The presumed allotetraploid species have essentially the same number of CK isozymes as the diploid X. tropicalis, suggesting a loss of duplicate gene expression or a cryptic expression due to coincident isozyme mobilities. It is possible that certain double banded isozymes in X. borealis and X. gilli represent the expressions of genes from a past polyploidization event.Two other genera of Pipidae, Hymenochirus and Pipa, differ from Xenopus in that they lack the CK‐III isozyme, and that the relative electrophoretic mobilities of the CK‐II and CK‐IV isozymes are reversed.
Role of the opercularis muscle in seismic sensitivity in the bullfrog Rana catesbeiana
Authors: Hetherington Thomas E. 
Published: June 2005

AbstractThe inner ear of anuran amphibians appears to be exceptionally sensitive to substrate vibration. The opercularis system, consisting of an opercularis muscle running from the shoulder girdle to a movable, cartilaginous operculum lying next to the inner ear, has been hypothesized to be involved in driving these seismic responses. Removal of the opercularis muscle of adult bullfrogs, Rana catesbeiana, caused clear decreases in microphonic responses of the inner ear to vibrations from 20–250 Hz and 0.05–5.0 cm/sec2 accelerations. Degree of decrease in responsiveness was variable between individuals and between different frequencies of stimulation, ranging up to 90% reduction at certain frequencies and in certain specimens. Decreases were most marked at lower frequencies below about 50 Hz. Additional removal of the levator scapulae superior muscle, which runs alongside the opercularis muscle from the shoulder girdle to ventrolateral portions of the otic capsule, also tended to depress responses, although this effect was substantially less (generally less than 10%) and also less consistent. As the opercularis muscle appears to be derived from the levator scapulae musculature, it is speculated that primitively seismic sensitivity was enhanced by a muscular connection that could transmit motion from the forelimb to the otic region, responsiveness being further enhanced by the subsequent evolution of the specialized opercularis system.
Melanin concentrating hormone (MCH) effects on teleost (Chrysiptera cyanea) melanophores
Authors: Oshima Noriko , Kasukawa Hiroaki , Fujii Ryozo , Wilkes Brian C. , Hruby Victor J. , de L. Castrucci Ana Maria , Hadley Mac E. 
Published: June 2005

AbstractThe in vitro biological actions of synthetic chum salmon melanin concentrating hormone (MCH) on melanophores of the blue damselfish (a teleost), Chrysiptera cyanea, were studied. This cyclic heptadecapeptide stimulated melanosome (melanin granule) aggregation (centripetal migration) within melanophores at a threshold concentration of about 10−10 M. The action of this putative hormone was not blocked by α‐ or β‐adrenoceptor antagonists. It was concluded that the effects of MCH were direct and were not mediated indirectly through the actions of adrenergic neurotransmitters released from nerve terminals. Further evidence for this view comes from the observation that, unlike the case of neurotransmitter release, melanosome aggregation in response to MCH proceeded in the absence of calcium. The possible role of MCH in the control of color change of teleost fishes is discussed.
Achromosomal cleavage of fertilized starfish eggs treated with cyclic guanosine 3′,5′‐monophosphate
Authors: Yamada Hisafumi , Hirai Setsuro , Suzuki‐Hori Chiyo , Nagano Hiroshi 
Published: June 2005

AbstractCyclic guanosine 3′,5′‐monophosphate (cGMP) was injected into fertilized starfish eggs in order to study the effects of this cyclic nucleotide on early embryogenesis. cGMP at approximate intracellular concentrations higher than 0.05 mM causes achromosomal cleavage in the presence of 1 mM caffeine, that is, each blastomere is devoid of a nucleus but not spindle and asters. The treated embryos cleave slower than control, never form blastulae, and disintegrate just before blastulation. cAMP, dibutyryl cGMP and dibutyryl cAMP failed to cause achromosomal cleavage. These results suggest that unphysiologically high levels of intracellular cGMP inhibit in vivo DNA synthesis of fertilized starfish eggs.
A spawning female‐specific substance reactive to anti‐chorion (egg envelope) glycoprotein antibody in the teleost, Oryzias latipes
Authors: Hamazaki Tatsuo , Iuchi Ichiro , Yamagami Kenjiro 
Published: June 2005

AbstractA substance with high immunoreactivity to rabbit anti‐chorion (egg envelope) glycoprotein antibody was found in liver and blood plasma as well as ovary of the spawning female medaka, while it was absent in the male and the non‐spawning female fish. This substance disappeared first from the hepatic cells of the female fish when it ceased spawning, whereas the immunoreactivity still remained in ovary and blood plasma. The relative electrophoretic mobility of the antigenic substance derived from these tissues was identical. The molecular weight and isoelectric point (pI) of the substance, as determined by polyacrylamide electrophoresis with varied gel concentrations and isoelectric focusing method, were about 60,000 and about 4.5, respectively. The substance was evidently distinct from the unreactive band of probable vitellogenin (ca 420,000 and pI, ca 3.8–4.0) which was found in blood plasma of the spawning female. In ovary sections, cytoplasm of the oocyte at the initial stage of chorion formation, containing neither vitellogenin nor egg yolk, showed a strong immunoreactivity. Cytoplasm of the oocytes, later than the vitellogenic stage, exhibited little immunoreactivity. Changes of this substance in connection with the spawning cycle strongly suggest that this substance is related to oogenesis.
Localization of 3H‐norepinephrine binding sites in the trout gill
Authors: Nekvasil Nancy P. , Olson Kenneth R. 
Published: June 2005

AbstractTritiated norepinephrine (Nepi) or Epinephrine (Epi) was perfused through isolated gills of rainbow trout (Salmo gairdneri) and the affinity of vascular tissues for the amines examined by autoradiography. Pillar cells and certain endothelial cells in the filamental sinus accumulate 3H‐Nepi extensively. The afferent and efferent filamental arteries and filamental nutrient vessels did not bind 3H‐Nepi. Pillar cell and venous endothelial accumulation is selective for Nepi; Epi is not accumulated by these cells, and Nepi uptake can be inhibited by imipramine. These results suggest that pillar and venous endothelial cells are involved in regulation of plasma Nepi.
Induction of deer antlers by transplanted periosteum I. Graft size and shape
Authors: Goss Richard J. , Powel Robert S. 
Published: June 2005

AbstractWhen discs of frontal periosteum from presumptive antler sites of 6–8 month old male fawns of the fallow deer are grafted beneath the foreleg skin, they will differentiate into pedicle bones and induce small antlers in the overlying integument. These antlers shed their velvet in the fall, and in succeeding years are replaced by larger outgrowths not exceeding 7 cm in length. Periosteal transplants 1.5 cm in diameter gave rise to ectopic antlers in 100% of the grafts, while discs measuring 1.05 cm, 0.75 cm and 0.4 cm did so in only 20% of the cases. Conversely, the donor sites produced antlers in 20–23% of the cases following removal of 1.05 cm or 1.5 cm of periosteum, while 80% and 100% grew antlers after deletions of 0.75 cm and 0.4 cm discs of periosteum, respectively. Semicircular grafts of periosteum induced antler development in most cases, especially when derived from the lateral halves of the antlerogenic region on the frontal bone. These findings confirm that the histogenesis of a deer's first pedicle and antler resides in the frontal periosteum over an area about 1.5 cm wide. They also show that leg skin is capable of antlerogenic development under the inductive influence of frontal periosteum, and that integumental wounding may enhance inductive interactions.
Termination of seasonal breeding in a weaver finch, Ploceus philippinus: Role of photoperiod
Authors: Chakravorty Krishna , Chandola‐Saklani Asha 
Published: June 2005

AbstractSeasonal gonadal regression in the photoperiodic weaver finch Ploceus philippinus occurs in the late summer despite the presence of long days. Earlier studies indicated a decline in photosensitivity in late summer, which might explain the failure of birds to respond to long days, resulting in gonadal regression. Results obtained in the present study suggest that 1) birds become refractory only to the stimulatory day lengths experienced in nature (longest day at 25° N 13.34 hr) and not to all long day lengths as in many other photoperiodic passerine species 2) birds become refractory in accordance with the day length they experience during the growth phase of the gonadal cycle. Thus birds held on 12 L/12 D become refractory to 12 L/12 D but are photosensitive to longer day lengths. Similarly, birds on natural day length become photorefractory to the longest day but are sensitive to higher day length, viz 15 L/9 D. 3) The long summer day lengths experienced in nature might cause the seasonal decline in photosensitivity.
Temperature‐sensitive mutations causing reversible paralysis in Caenorhabditis elegans
Authors: Hosono Ryuji , Kuno Sigeru , Midsukami Minoru 
Published: June 2005

AbstractA method has been developed for the isolation of temperature‐dependent paralytic mutants of the nematode Caenorhabditis elegans, based on a screening procedure using short‐time exposure to 30°C. Of ten mutants isolated, eight lose their motilities between 30°C and 33°C without prominent changes in body forms. The other two strains that are mainly described in this report are accompanied by alterations in body forms. One mutation, cn101, is recessive and an allele of cha‐1. The cn101 mutant shows reversible paralysis at 30°, accompanied by a hypercontracted and coiled body form. At the restrictive temperature, the strain is resistant to all tested inhibitors of acetylcholinesterase (AChE). Another mutation, designated mah‐2 (cn110), is a sex‐linked semidominant that is mapped as 0.6 map units left of dpy‐6. The cn110 mutant is rapidly paralyzed at the restrictive temperature and has a straight and rigid body form; the mutant rapidly recovers when the temperature is lowered. No disorganization of the muscle structure was detected by polarized light and electron microscopic inspection.
Identification of zona binding proteins of rabbit, pig, human, and mouse spermatozoa on nitrocellulose blots
Authors: O'Rand Michael G. , Matthews Jessica E. , Welch Jeffrey E. , Fisher Susan J. 
Published: June 2005

AbstractMammalian fertilization is a multi‐step process with different requirements for specificity at each step. In the present report we have examined the binding of spermatozoa to homologous and heterologous zonae pellucidae. The homologous zona binding proteins (ZBP) of ejaculated rabbit, pig and human spermatozoa and epididymal mouse spermatozoa have been identified. The rabbit's ZBPs have relative molecular weights (MW) of 32K, 18K, 16K and 14K; the pig's major ZBP is 16K while human spermatozoa bind human zona protein at 17K and 18K. Mouse sperm ZBPs are 19K, 18K and 16K.
Trimethylamine oxide and the maintenance of volume of dogfish shark rectal gland cells
Authors: Kleinzeller Arnost 
Published: June 2005

AbstractDeterminants of the steady‐state vol of the dogfish shark (Squalus acanthias) rectal gland cells were studied. The cellular levels of trimethylamine oxide (TMAO) in fresh tissue and slices incubated aerobically 60 min in standard (TMAO‐free) elasmobranch saline were close to those in the plasma (71 ± 5 mM S.E.M.); therefore, under these conditions, the cell membrane appears to be impermeable to this solute. However, depolarization of the cells in high‐K+ media produced a rapid loss of TMAO. Thus, TMAO is a major, effectively impermeant solute in the rectal gland cells. The osmolarity of cell solutes in tissue water (fresh and incubated slices) did not differ significantly from values in the plasma or incubation medium, demonstrating the absence of an osmotic pressure gradient across the cell membrane. An analysis of a simple model of cell solutes under steady‐state conditions shows that the presence of an (effectively) impermeant osmolyte decreases the cellular concentration of bulk cations. The analysis is consistent with available observations on the distribution of cell Na+ and K+ in tissues containing high concentrations of (nitrogeneous) osmolytes. One simplifying assumption of the model, i.e., identity (or closeness) of the respective reflection coefficients σ for Na+ and K+ passage through the cell membranes could not be verified. Compared to available data on the steady‐state cellular fluxes of 42K+ in slices of the rectal gland, the uptake of 22Na+ by the tissue was slow (the derived rate constant k′ = 0.017 min−1, i.e., about one tenth of that for K+). Hence, σNa < σK. On the other hand, 36Cl− rapidly exchanged with cell Cl− with the first rate constant (k′ = 0.60 + 0.12 min−1) close to that of 3H2O.
Localization of cytoplasmic determinants responsible for primary mesenchyme formation and gastrulation in the unfertilized egg of the sea urchin Hemicentrotus pulcherrimus
Authors: Maruyama Yoshihiko K. , Nakaseko Yukinobu , Yagi Shintaro 
Published: June 2005

AbstractThe jelly canal of the unfertilized egg of the sea urchin H. pulcherrimus was found to serve as a stable landmark of the egg axis. The eggs were bisected with a micro glass needle into two egg‐halves either equatorially or meridionally in relation to the egg axis defined by the jelly canal. The development of both egg‐halves after fertilization was observed 1 or 2 days later until the control embryos reached the gastrula stage. The embryo derived from the vegetal half formed primary mesenchyme and gastrulated while the animal half remained as the permanent blastula forming neither primary mesenchyme nor archenteron. Both embryos obtained by the meridional bisection formed primary mesenchyme and gastrulated. The presence of the female pronucleus or its adjacent cytoplasm was not a prerequisite for the occurrence of primary mesenchyme formation and gastrulation. These results indicate that unfertilized eggs already localize the cytoplasmic determinant responsible for primary mesenchyme formation and gastrulation. Localization of the cytoplasmic determinant occurs independently of formation of the cortical pigmentation polarity.
The trophotaenial placenta of a viviparous goodeid fish. III: Protein uptake by trophotaeniae, the embryonic component
Authors: Lombardi Julian , Wourms John P. 
Published: June 2005

AbstractProtein uptake and degradation by trophotaenial cells of the viviparous goodeid fish Ameca splendens were studied colorimetrically and ultrastructurally using horseradish peroxidase (HRP) as a tracer and acid (ACPase) and alkaline (ALPase) phosphatase cytochemistry. Trophotaeniae are ribbon‐like external projections of the embryonic gut that are equivalent to greatly hypertrophied intestinal villi. During gestation within the ovarian lumen, trophotaeniae are directly apposed to the internal ovarian epithelium (IOE) where they establish a placental association between the developing embryo and maternal organism. Trophotaenial absorptive cells possess an ALPase reactive brush border, an endocytotic apparatus, and ACPase reactive standing lysosomes. Ultrastructural studies of protein uptake indicate that cells of the trophotaenial epithelium take up HRP by micropinocytosis and degrade it within lysosomes. Initially (from 1.5–10 min), HRP is taken up in vitro at 22° C at the apical cell surface and passes via endocytotic vesicles into an apical canalicular system. From 1.5 to 10 min exposure, HRP passes passes from the apical canalicular system to a series of small collecting vesicles. After 10 min, HRP is detected within large ACPase reactive supranuclear lysosomes. Three hours after an initial 1 h exposure to HRP, most peroxidase activity within supranuclear lysosomes is no longer detected. Presence of Golgi complexes, residual bodies, and secretory granules in the infranuclear cytoplasm suggest that products of protein uptake and hydrolysis are discharged across basal and lateral cell surfaces and into the trophotaenial circulation. Trophotaeniae of embryos incubated in vitro in HRP‐saline take up HRP at an initial rate of 13.5 ng HRP/mg trophotaenial protein/min. The system becomes saturated after 3 h. Trophotaeniae incubated at 4°C show little or no uptake. In trophotaeniae continuously pulsed with HRP for 1 h, then incubated in HRP‐free saline, levels of absorbed peroxidase declined at a rate of 0.5 ng/mg trophotaenial protein/min. HRP does not appear to enter the embryo via extratrophotaenial routes. These findings are consistent with the putative role of trophotaeniae as the embryonic component of the functional placenta of goodeid fishes. Trophotaenial uptake of maternal nutrients accounts for a massive (15,000%) increase in embryonic dry weight during gestation.
Significance of Con A binding sites in the conjugation of Euplotes vannus
Authors: Lueken W. , Oelgemöller B. 
Published: June 2005

AbstractAggregations of Con A binding sites that occur on the surface of preconjugant cells have been studied in order to reveal their possible functions in the conjugation process. By means of a newly adapted horseradish peroxidase method, they can be visualized in distinctly shaped oval fields (OF) as soon as 10–15 min after mixing cells of opposite mating types. Cycloheximide (CHX) prevents establishment of new OFs but does not effect preexisting ones. In the absence of previously developed OFs, cells cannot form pairs. However, even if OFs are fully present, pairing still can be inhibited by CHX, high K+ concentrations (≥ 60 mmol/liter), or the K+‐channel blocker tetraethyl‐ammonium (TEA, 10 mmol/liter). A doublet cell with OFs on both halves normally binds to one singlet. This partner, after a stay of 10 min in an angled agglutination position, quickly rotates into the parallel pairing position. At this moment, the doublet suddenly loses its affinity for complementary cells at its free OF. This behavior explains why many doublets pair only with one singlet. The Con A binding sites themselves seem not to be active in cell pairing; they are regarded as a marker for a region of the cell surface whose contact with a complementary cell subsequently results in the unmasking of unidentified compounds that serve as adhesive agents and/or the hinge for the quick rotation of agglutinated cells.
Development of the masseter muscle and oral behavior in the pig
Authors: Herring Susan W. , Wineski Lawrence E. 
Published: June 2005

AbstractDuring mastication the adult pig masseter contracts with a complex pattern involving a wave of electromyographic (EMG) activity moving from the ventro‐rostral corner to the dorso‐caudal corner. The present study was undertaken to ascertain the ontogeny of that contraction pattern. Anatomical measurements were made on masseters from fetal, infant, and juvenile pigs. EMG activity from different parts of the masseter was recorded along with oral movements in infant and juvenile pigs as they suckled, drank, and chewed on food and non‐food objects. The basic arrangement of muscle fibers and tendinous aponeuroses was found to be the same in all ages. The longest and most vertical fibers were found rostrally and ventrally, whereas the shortest and most horizontal fibers were found caudally and dorsally. The length of fasciculi decreased with age, relative to muscle weight. Variance in length among different parts of the muscle increased with age. Fetal masseters were oriented generally more horizontally than the masseters of older animals, except that the dorso‐caudal corner, usually the most horizontal portion, is not developed in fetuses. The contraction patterns within the infant masseter were less complex than those of older animals; only the dorso‐caudal corner was distinct. The further development of intramuscular differences in activity may be associated with the increasing anatomical complexity of the masseter, which augments its functional capabilities.
Hormonal regulation of growth and life span of bullfrog tadpole tail epidermal cells cultured in vitro
Authors: Nishikawa Akio , Yoshizato Katsutoshi 
Published: June 2005

AbstractEpidermal cells were dissociated from tails of the bullfrog tadpole, Rana catesbeiana, and cultured to investigate their response to steroid and thyroid hormones. Charcoal‐treated serum (CTS) was used in the growth medium when cells were to be grown in the absence of steroid and thyroid hormones. The cells could be maintained for 2 weeks with a small increase in cell number in medium that contained CTS (CTS medium). Addition of cortisol to CTS medium increased both cellular attachment to the culture dishes and the proliferation of the attached cells with an optimum concentration of 5 × 10−7 M. The cells remained viable and attached for at least a week. Cortisol stimulated the rate of protein synthesis 1.8‐fold but did not alter the rate of DNA synthesis. The cells did not proliferate in the medium containing triiodothyronine (T3) and detached themselves from the dish within 5 days, which occurred in a dose‐dependent manner with a maximum effect at 10−8 M. It drastically decreased the rate of DNA synthesis but did not influence the rate of protein synthesis. These responses of cells to cortisol and T3 may reflect growth and death of tail epidermal cells in vivo at metamorphosis.