bluuebunny/crossref_metadata_2025_split huggingface dataset:
Histochemical determination of the fiber composition of locomotory muscles in a lizard, Dipsosaurus dorsalis
Authors: Putnam Robert W. , Gleeson Todd T. , Bennett Albert F. 
Published: June 2005

AbstractA histochemical survey was done on the fiber composition of 12 different locomotory muscles in the lizard Dipsosaurus dorsalis. Three types of fibers were found in all muscles: (1) fast‐twitch‐glycolytic (FG); (2) fast‐twitch‐oxidative‐glycolytic (FOG); and (3) tonic fibers. Virtually all locomotory muscles contain some tonic fibers. Most muscles have bulk white regions (containing mostly FG fibers) and distinct red, oxidative regions (with FOG and tonic fibers). These red regions are predominantly located around the joints in the hind limb muscles, and probably serve a postural and joint‐stabilizing function. The predominance of FG fibers in the bulk white regions is well‐correlated with the rapid, anaerobically supported predator escape behavior of D. dorsalis.
Proliferation, growth, and migration of nuclei the yolk syncytium of Salmo and Catostomus
Authors: Long Wilbur L. 
Published: June 2005

AbstractNuclei of the yolk syncytial layer (YSL) were counted, measured, and mapped at several stages of morphogenesis selected representatives of the Clupeiformes and Cypriformes. The data show coordated motion of nuclei before and durg morphogenetic movements of the cellular blastodisc. This motion may be used to trace cytoplasmic flow the syncytium at early stages. The data show that YSL nuclei proliferate mitotically at first. Further proliferation, after mitosis ceases, happens by an unknown mechanism. Growth of YSL nuclei Salmo gairdneri does not occur by fusion of smaller nuclei as others have suggested for teleosts. The matter is still unsetted for Catostomus commersoni.
In vitro capacitation and the chemically induced acrosome reaction in bovine spermatozoa
Authors: Byrd William 
Published: June 2005

AbstractThe effect of bovine serum albumin (BSA), calcium, and ionophore A23187 on in vitro capacitation and the induction of the acrosome reaction in bovine spermatozoa was examined using light, fluorescent, and electron microscopy and spectrofluorometry. Transmission electron microscopy of fixed spermatozoa labeled with the plant lectin concanavalin A indicated that a significant redistribution of lectin binding sites requires at least three hours of incubation in a capacitating medium that contains BSA and calcium. Spermatozoa underwent capacitation and the acrosome reaction following a minimum incubation time of 2–3 hours in capacitating medium in the continuous presence of calcium ionophore A23187 (1–10 μm). The induction of the acrosome reaction was determined by light microscopy of fixed‐stained cells as well as transmission electron microscopy. These data suggest that a minimum of 2–3 hours is required for in vitro capacitation of bovine spermatozoa. Capacitation was also examined using the tetracycline‐HCl (T‐HCl) binding assay of Ericsson ('67). Measurement of fluorescence by spectrofluorometry and by fluorescence microscopy demonstrated that the level of fluorescent T‐HCl bound to spermatozoa was dependent upon the concentration of BSA, the presence of calcium, and time of incubation. However, the loss of bound T‐HCl does not coincide with the development of the capacitated state determined by lectin binding and induction of the acrosome reaction. It is suggested that this loss of fluorescence may represent either a preliminary step in capacitation or result from nonspecific binding of fluorescent label to BSA.
Glycogen metabolism in the developing accessory lobes of Lachi in the nerve cord of the chick: Metabolic correlations with the avian glycogen body
Authors: Benzo Camillo A. , De Gennaro Louis D. 
Published: June 2005

AbstractGlycogen synthase, glycogen phosphorylase, glucose‐6‐phosphate dehydrogenase, 6‐phosphogluconate dehydrogenase, and glucose‐6‐phosphatase were determined for the first time in the accessory lobes of Lachi from late embryonic chicks. The activities of these enzymes were compared with those found in other glycogen‐metabolizing tissues, specifically the glycogen body, liver, and skeletal muscle, obtained from the same embryos. The data show that, as in the glycogen body, the accessory lobes of Lachi lack glucose‐6‐phosphatase, but contain relatively high activity levels of glycogen synthase I, total and active glycogen phosphorylase, and the dehydrogenases of glucose‐6‐phosphate and 6‐phosphogluconate. The percent of glycogen synthase I activity in the Lachi lobes is from two‐ to 20‐fold greater than that observed in the glycogen body, liver, or muscle, whereas the percent of glycogen phosphorylase a activity is comparable to that of the liver, but greater than that in the glycogen body or muscle. The activity of each dehydrogenase of the pentose phosphate cycle in the Lachi lobes is similar to that noted in the glycogen body, but is over two‐ or fivefold greater than that activity found in muscle or liver. Our data, together with other recent evidence, suggest that the role of glycogen in these functionally enigmatic tissues may be to support the precocious process of myelin synthesis in the developing bird, as well as possibly to provide alternate sources of energy for the avian central nervous system.
Glycoprotein secretions of the epididymis in the rabbit and hamster: Localization on epididymal spermatozoa and the effect of specific antibodies on fertilization in vivo
Authors: Moore H. D. M. 
Published: June 2005

AbstractTo assess the functional significance of glycoprotein secretions of the rabbit and hamster epididymis during sperm maturation and fertilization, antibodies have been raised against acidic protein fractions isolated from epididymal fluid. Specific antiserum was elicited against each of three rabbit glycoproteins designated R1, R2, and R3 with isoelectric points of pI 3.45, 4.15, and 4.65 respectively, and against one hamster glycoprotein (HI), pI 3.40.Epididymal glycoproteins on the surface of washed spermatozoa from various regions of the epididymis were localized by the fluorescent antibody technique and by sperm agglutination with antiserum. They were first detected on restricted regions of spermatozoa from the distal caput and corpus epididymidis and each antigen had a characteristic binding pattern. The effect of specific antibodies on fertilization in vivo was tested in rabbits by preincubating cauda epididymal spermatozoa with heat‐treated antiserum or univalent immunoglobulin fragments before their deposition into oviducts of does induced to ovulate. In all cases, fertilization rates were significantly reduced (P ≤ 0.05) compared with controls, the most effective antiserum being against glycoprotein antigen R1 found only on the anterior acrosome of spermatozoa. Heat‐treated antiserum against H1 glycoprotein placed in the bursal cavity of ovulating females significantly inhibited fertilization in the hamster (P ≤ 0.005). These results are discussed in relation to the modification to the sperm plasmalemma during maturation.
The effect of temperature on tyrosinase activity in Himalayan mouse skin
Authors: Kidson S. H. , Fabian B. C. 
Published: June 2005

AbstractThe tyrosinase activity of Himalayan mouse skin homogenates was measured over a range of temperatures using two sensitive radiometric assays—namely, (1) the measurement of 14C‐tyrosine incorporation into melanin, and (2) the measurement of 3HOH released as a by‐product of 3H‐tyrosine hydroxylation. Results show that Himalayan tyrosinase is maximally active at temperatures well below normal body temperature (15°C to 25°C). These results are in support of Danneel's visual observations ('41) that “ferment” activity of Himalayan rabbit skin is absent at temperatures above 25°C.Further results suggest the presence of a tyrosinase inhibitor in Himalayan mouse skin. First, removal of a low molecular weight fraction from Himalayan skin homogenates resulted in an increase in tyrosinase activity. Second, recombination of the low molecular weight fraction to the homogenate from which it was originally separated resulted in a decrease in tyrosinase activity when assayed at 37°C, but no decrease when assayed at 25°C. It is proposed that at the normal body temperature of 37°C, tyrosinase from Himalayan skin is strongly bound to an inhibitor. At lower body temperatures, the affinity of the enzyme for the inhibitor decreases, thus allowing the synthesis of melanin to increase. This change in affinity of the enzyme for the inhibitor could be regulated by temperature‐induced conformational changes in either the enzyme or the inhibitor or both.
Two types of tonic fibers in lobster muscle based on enzyme histochemistry
Authors: Kent Karla S. , Govind C. K. 
Published: June 2005

AbstractTonic fibers are differentiated into two types based on enzyme histochemistry in the claw opener and closer muscle of the lobster Homarus americanus. Some of the fibers have a much lower myofibrillar ATPase activity and much higher oxidative capacity (indicated by NADH diaphorase) than the remainder. These slower‐contracting, more fatigue‐resistant fibers are regionally distributed in the claw muscles. The occurrence of two types of tonic fibers particularly in the opener muscle, which is innervated by a single slow excitor axon, shows that the oxidative properties of these fibers are not controlled simply by the presence of this motoneuron as previously proposed.
Poly (A)·oligo (dT)‐stimulated DNA polymerase activity in preimplantation mouse embryos
Authors: Kiessling Ann A. , Weitlauf Harry M. 
Published: June 2005

AbstractDNA polymerase activity with Poly (A)·oligo(dT) as a template‐primer has been found in preimplantation mouse embryos. A sharp increase in enzyme activity was observed at the time of formation of inner cell mass (ICM) and trophoblast cells. Differential inhibition of enzyme activity before and after ICM formation raised the possibility that more than one Poly(A)·oligo(dT)‐directed DNA polymerase was detected.
Differentiation of melanomas occurring in platyfish‐swordtail hybrids of different ages: An ultrastructural study
Authors: Esaka Takashi , Asada Mari , Wakamatsu Yuko , Ozato Kenjiro 
Published: June 2005

AbstractThe degree of differentiation of two types of hereditary melanomas of interspecific hybrids between the spotted variety of the platyfish (Xiphophorus maculatus) and the swordtail (Xiphophorus helleri) was examined electron microscopically. Melanomas of the fry consisted mainly of pigmented cells containing intermediately matured melanosomes and few other cytoplasmic structures. Melanomas of the adult consisted of lightly pigmented cells having a small number of immature melanosomes; numerous polysomes; well‐developed, rough‐surfaced endoplasmic reticulum (RER) and Golgi systems; and irregularly shaped nuclei. Thus the fry and adult melanomas appear to represent relatively well‐ and poorly differentiated states of fish melanophores, respectively. Amela‐notic melanomas in the adult melanotic F1 generation were also characterized. Virus‐like particles were often found in the nuclei of both melanotic and amelanotic melanoma cells in the adult fish.
Preamputation and postamputation histology of the neonatal opossum hindlimb: Implications for regeneration experiments
Authors: Fleming Michael W. , Tassava Roy A. 
Published: June 2005

AbstractMammalian limbs generally do not regenerate, regardless of added hormonal or nervous stimulation, whether amputation occurs during fetal life or post‐partum. The one exception, the newborn opossum, has been reported to regenerate the incompletely developed hindlimb (Mizell, '68). In an attempt to repeat and extend these earlier findings, we have examined the histology of the neonatal opossum hindlimb. After amputation on day 4 post‐partum, we correlated the histology of the amputated segment with the histology of the remaining stump after a “regeneration time” of several weeks. Amputations through the middle of the hindlimb on day 4 did not transect the tibia and fibula because the rudiments of these bones are still almost completely inside the body wall. Midlimb amputations transected instead the tarsal rudiments or even phalangeal rudiments. Limb stumps were therefore left with distal skeletal rudiments which subsequently underwent further embryonic development and growth giving the erroneous impression of regeneration. Of 30 amputated hindlimbs, none showed regeneration.
Development of swimming behavior in sea urchin embryos. I.
Authors: Maruyama Yoshihiko K. 
Published: June 2005

AbstractDevelopment of behavior in sea urchin embryos and larvae was studied with special attention to rotation on the animal‐vegetal axis. Within the fertilization membrane, each embryo rotated either clockwise or counterclockwise on the animal‐vegetal axis and the direction of rotation (= spin) sometimes reversed in the same embryo. However, the symmetric pattern of spinning motion in prehatching embryos was lost liberation of embryos from the fertilization membrane. Embryos hatching out with counterclockwise spin (as viewed from the vegetal region) maintained the same direction of spin even after hatching, whereas embryos with clockwise spin reversed the direction of spin through a characteristic transient swimming pattern. Eventually, all embryos swam with the animal pole forward and rotated counterclockwise on the animal‐vegetal axis. A developmental change of swimming behavior, first appearing at the pluteus stage, is a transient reversal of swimming direction. The direction of rotation during this backward swimming was invariably “counterclockwise” as in the case of forward swimming, if the larva was viewed from the rear with respect to the swimming direction.
Responses of denervated adult newt limb stumps to reinnervation and reinjury
Authors: Salley Judith D. , Tassava Roy A. 
Published: June 2005

AbstractIt is well known that denervated adult newt limbs do not regenerate. Not understood is why denervated newt limb stumps fail to initiate regeneration upon reinnervation. In an effort to define the regeneration limiting factors, we examined the histology of long‐term denervated newt limb stumps and tested the effects of various kinds of reinjury. In 5‐week denervated limb stumps there were present dedifferentiated cells, differentiated cartilage, and densely packed layered cells. The epidermis covering the limb tip resembled skin epidermis rather than wound epidermis. The kinds of reinjury that were successful in restoring the regeneration capabilities to 5‐week denervated limb stumps included: reamputation (100%), a single razor incision (60%), and removal of the healed tissues from the distal limb tip (70%). The results of this study emphasize the importance of both injury and wound epidermis in initiating regeneration.
Biochemical studies of mammalian oogenesis: Kinetics of accumulation of total and poly(A)‐containing RNA during growth of the mouse oocyte
Authors: Sternlicht Andrew L. , Schultz Richard M. 
Published: June 2005

AbstractKinetics of accumulation of total and poly(A)‐containing RNA have been measured during growth of the mouse oocyte. Total RNA from oocytes isolated at discrete stages of growth was determined by two independent micro‐assays. The fully‐grown oocyte contained about 0.60 ng of RNA. Kinetics of accumulation of total RNA with respect to oocyte volume were biphasic. Small, growing oocytes (about 30 pi) contained about 0.20 ng of RNA/oocyte. The amount of RNA increased in a quasi‐linear fashion until oocyte volume was about 160 pl, at which point there was about 0.57 ng of RNA/oocyte. Thus oocytes about 65% of their final volume had accumulated about 95% of the total amount of RNA present in the fully‐grown oocyte. The relative amount of poly(A)‐containing RNA in oocytes of various size was determined by in situ hybridization of [3H]poly(U) to ovarian sections from juvenile mice of known age, followed by autoradiography. The kinetics of accumulation of poly(A)‐containing RNA were similar to those of total RNA; oocytes about 70% of their final volume had accumulated about 95% of the amount of poly(A)‐containing RNA present in the fully‐grown oocyte. The poly(A)‐containing RNA resided predominantly in the cytoplasm and no obvious cytoplasmic localization was observed.Kinetics of accumulation of total RNA, which is mainly ribosomal, and poly(A)‐containing RNA were consistent with levels of RNA polymerases I and II measured by others during oocyte growth (Moore and Lintern‐Moore, '78). The number of ribosomes that could be made from the amount of rRNA present at various stages of growth was compared to the actual number of ribosomes calculated from a published morphometric study (Garcia et al., '79). Kinetic differences in accumulation between the theoretical and actual number of ribosomes suggested oocyte ribosomes are recruited into cytoplasmic lattice structures. These structures accumulate during oocyte growth and have been postulated to be a ribosomal storage form. In addition, the results from this study are compared to results derived from lower species.
Analysis of perinotochordal materials. I. Studies on proteoglycans synthesis
Authors: Vasan Nagaswamisri 
Published: June 2005

AbstractPerinotochordal proteoglycans have been shown to influence somite chondrogenic differentiation. However, information concerning the composition of the proteoglycan molecules synthesized by the notochord, or the exact type of molecule necessary for the induction of somite chondrogenesis is not known. The results of the present study indicate that the proteoglycan extracted from the 8 day old notochord culture consists of predominantly small proteoglycans, while the large aggregates form less than 30% of the total. The chondroitin sulfate composition also shows a cartilage type of proteoglycan molecules synthesized by the notochord.
State of water and electrolytes in mammalian cells during maturation and differentiation
Authors: Hempling H. G. , Cicoria A. D. , Dupre A. M. , Thompson S. 
Published: June 2005

AbstractThe state of water and electrolytes was examined (1) in the rat erythroblastic leukemic cell, as a model of a maturing erythrocyte; (2) in the mouse Ehrlich ascites tumor cell during the cell cycle as a model of the uninhibited proliferating cell; and (3) in a clonal population of proliferating and differentiating precursor cells cultured from the bone marrow of the rat. Methods used were phenomenological and included assessments of the volumes of osmotically active water, content of K+, Na+, and Cl−, volumes of distribution for Na+, urea, and ethylene glycol, and the thermodynamics of transport of water and solutes into and out of the cell. The erythroblastic leukemic cell provided evidence for compartments of osmotically active and inactive water and solute. The synchronized ascites tumor cell indicated that these compartments varied during the cell cycle. Membrane function as defined by its permeability to water also varied during the cell cycle. When proliferating cells matured, changes in membrane permeability to water and to nonelectrolytes also correlated with successive stages of differentiation.
Amino acid cycling in ribbed mussel tissues subjected to hyperosmotic shock
Authors: Bishop Stephen H. , Greenwalt Dale E. , Burcham James M. 
Published: June 2005

AbstractVariations in the high concentrations of intracellular amino acids in the tissues of osmoconforming, euryhaline animals such as the ribbed mussel (Modiolus demissus) appear to have a major role in adjusting intracellular osmotic pressure in response to extracellular osmotic change. The experiments discussed here on the metabolic origins and fates of these amino acids are part of a continuing study on the physiological mechanisms regulating the concentrations of these amino acids. Tissues isolated from ribbed mussels adapted at 12 o/oo were incubated for 8 hrs. in artificial seawater media at 12 o/oo or 32 o/oo. The total marked increase in total intracellular amino acid levels at 32 o/oo vs. 12 o/oo was not blocked by addition of 1 mM amino oxyacetic acid (AOA). However, with AOA the usual increase in alanine and proline concentrations was offset by increases in a variety of amino acids including ornithine. AOA inhibited transaminases associated with ornithine, alanine, and glutamate metabolism (I50s:10−8 to 10−5 M) but did not inhibit the L‐amino acid oxidase. 14C‐tracer experiments with isolated gill tissue indicated no synthesis of proline from glutamate and enhanced synthesis of proline, alanine, and glutamate from ornithine and arginine at 32 o/oo vs. 12 o/oo. L‐amino acid oxidase, proline oxidase, glutamate dehydrogenase, and enzymes in the metabolic pathway between arginine and proline were found in cell‐free extracts of gill tissue. During hyperosmotic stress, proline was apparently derived from the phosphoarginine‐arginine pool, whereas alanine and the other accumlating amino acids have multiple metabolic origins including the amino acids released during protein turnover, the metabolites of the phosphoarginine pool, and possibly endogenous carbohydrate.
Volume regulation in aquatic invertebrates
Authors: Oglesby Larry C. 
Published: June 2005

AbstractVolume regulation in marine and estuarine invertebrates is usually assessed by the extent of restoration of original weight following a salinity transfer. However, volume regulation also includes the limitation of osmotic water movements. Mechanisms of volume regulation include (1) reduction of permeability of the body wall to water, reducing the rate of osmotic water movement; euryhaline species are less permeable to water than stenohaline species, and may show further adaptive reduction when in low salinities; (2) expulsion of excess water following osmotic influx, primarily as bulk elimination in the urine; and (3) changes in the numbers of extracellular osmolytes, also reducing the osmotic gradient, the major route being loss of solutes to the medium across the body wall and through the urine. Two theoretical approaches to analysis of volume regulation are discussed (Machin, '75; Oglesby, '75) and it is concluded that while both are somewhat imprecise, the approach of Oglesby ('75) has more versatility and resolving power in dealing with both osmoregulators and osmoconformers.
The role of amino acids in anaerobiosis and osmoregulation in bivalves
Authors: Zurburg Wouter , De Zwaan Albertus 
Published: June 2005

AbstractThe role of free amino acids as solutes for cell volume regulation in marine molluscs under salinity stress is well established. Under hypoosmotic stress the intracellular concentrations of amino acids decrease by extrusion from the cells, followed by deamination and/or excretion. However, no uncontroversial evidence is available about mechanisms involved in the enlargement of the free amino acid pool during hyperosmotic stress.Since anaerobic metabolism in bivalves can result in the accumulation of the amino acids alanine and glutamate, a possible contribution of the anaerobic metabolic pathways to the osmotic adjustment of the cell during hyperosmotic stress has been considered. The net gain of amino acids implies the fixation of ammonia to 2‐oxo acids. The low activity of glutamate dehydrogenase found in bivalves does not exclude its role in osmoregulation and anaerobiosis. Another ammonia‐fixating enzyme may be alanine dehydrogenase, but so far evidence for its presence in bivalves is lacking. In bivalves the source of ammonia for these enzymes may be found in part in uric acid or other amino compounds that are present in reasonable amounts.