bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of sustained swimming on rainbow trout muscle structure, blood oxygen transport, and lactate dehydrogenase isozymes: Evidence for increased aerobic capacity of white muscle
Authors: Davie Peter S. , Wells Rufus M. G. , Tetens Vilhelm 
Published: June 2005

AbstractGroups of rainbow trout (Salmo gairdneri, Richardson) were continuously swum at 20 cm s−1 (1.0 body lengths s−1) for 0, 3, 30, and 200 days. No significant changes in fish condition factor, combined red and white muscle mass, muscle fibre size or fibre size distribution were observed. After 200 days of swimming there was a significant 2.2 fold increase in red muscle mass.Number of capillaries per red muscle fibre increased significantly in each group by a maximum of 27% after 200 days exercise. Number of capillaries per white muscle fibre increased significantly by 95% after 200 days exercise. Blood lactate, haemoglobin (Hb) concentration haematocrit, erythrocyte adenosine triphosphate, and whole blood oxygen affinity P50 were unchanged by swimming. After 30 and 200 days swimming there was a shift in expression of white muscle lactate dehydrogenase (LDH) isozymes from LDH‐A to LDH‐B. Within the duplicated LDH‐B isozyme complex, there was a shift in expression from LDH‐B to LDH‐B′ subunits. These results suggest that sustained swimming at 1−1 bl s−1 increased the aerobic capacity of red and particularly white (fast) muscle of rainbow trout but did not alter the gas transport characteristics of the blood.
Metamorphosis of the American eel, Anguilla rostrata LeSeur: I. Changes in metabolism of skeletal muscle
Authors: Egginton Stuart 
Published: June 2005

AbstractUnequivocal demarcation between immature, nonmigratory yellow eels and migratory silver eels of greater sexual maturity is possible by measuring eye diameter and retial capillary length, which undergo a 1.5‐ and 2.3‐fold increase during metamorphosis, respectively. Anatomical arrangement of trunk musculature is similar in the two groups except for an increased depth of slow muscle in silver eel. Histochemical analysis reveals a progressive increase in numbers of “displaced” fast fibres within slow muscle of the lateral line triangle in maturing eels, although these are unlikely to affect recruitment pattern of muscle fibre types. Previous studies have suggested greater involvement of fast muscle in locomotion of migratory eels. In contrast, estimates of enzyme activity in fast muscle suggest an inadequate aerobic capacity to fuel sustained activity. Myoglobin content is extremely low, around 0.4 nM g wet wt−1. Prolonged anaerobic metabolism is also discounted as a migratory strategy. Increased energy provision for migration is apparently derived from increased capacity for both aerobic carbohydrate metabolism and mitochondrial fatty acid oxidation within slow muscle of silver eels. Activity of hexokinase (HK) shows a 1.6‐fold increase (to 0.51 μM g wet wt−1) and carnitine palmitoyltransferase (CPT) a 3.1‐fold increase (to 0.22 μM g wet wt−1 min−1), suggesting a maximal flux through these pathways of 18 and 14 ATP equivalents, respectively. However, the fatty acyl transferase system of skeletal muscle mitochondria displays up to threefold greater activity with palmitoleoyl CoA (C16:1) as substrate than with the usual palmitoyl CoA (C16:0). Slow muscle of silver eel is therefore capable of deriving aerobic energy from free fatty acids and carbohydrate in the ratio 2.3:1. Differences in aerobic enzyme activities are not paralleled by myoglobin content of slow muscle, being 15 and 16 nM g wet wt−1 for yellow and silver eel, respectively. Structural reorganization of muscle fibres during metamorphosis, however, results in a twofold elevation of cytoplasmic myoglobin concentration in silver eel. It would appear that dramatic differences in metabolic capacity between life history stages of eel is required to overcome locomotory inefficiency of yellow eels and to “preadapt” silver eels for migratory activity. This increased locomotory capacity may be amplified by a subsequent training response.
Development of the eye‐antenna imaginal disc and morphogenesis of the adult head in Drosophila melanogaster
Authors: Haynie John L. , Bryant Peter J. 
Published: June 2005

AbstractWe have studied the organization and development of the eyeantenna imaginal disc of Drosophila melanogaster. We examined the pattern of gynandromorph mosaicism and determined the “sturt distances” between 42 different structures of the head, antenna, and maxillary palpus. A morphogenetic map based on these sturt distances resembles more closely in size and shape that of a single thoracic segment than that of two or more adjacent segments, suggesting that the eye‐antenna disc is derived from a single embryonic body segment. We examined the morphology of the eye‐antenna discs in situ in late third‐instar larvae in serial cross sections. The two discs are connected medially by a thin cellular membrane that probably serves to join the two discs during evagination and morphogenesis of the adult head. A fate map of the imaginal disc was established by cutting the mature disc into fragments and transplanting the fragments into host larvae for metamorphosis. The peripodial layer of the eye‐antenna disc is thickened in several regions, and our data suggest that these thickened areas represent primordia of adult head structures. A comparison of the location of precursors in the imaginal disc with those of the differentiated structures of the adult head revealed the nature of the morphogenetic movements that must occur during evagination and differentiation.
The defender role of the precocious larvae ofCopidosomopsis tanytmemusCaltagirone (Encyrtidae, Hymenoptera)
Authors: Cruz Y. P. 
Published: June 2005

AbstractA specialized larval morph, here called the precocious larvae, is present in broods of the polyembryonic encyrtid wasp,Copidosomopsis tanytmemusCaltagirone, an egg‐larval parasite of the Mediterranean flour moth,Anagasta kuehniella(Zeller). The precocious larvae are clonally derived from the same embryonic cells that produce the normal larvae. In contrast to their normal siblings, precocious larvae have well‐developed cranial structures and mouthparts, and are extremely motile. The most unusual feature of precocous larvae, however, is their failure to attain reproductive age; they invariably die in the host hemolymph as untransformed larvae. Competition experiments with the braconidPhanerotoma flavitestaceaFischer or one of the ichneumonidsVenturia canescens(Gravenhorst) andTrathalasp. showed that precocious larvae injured or killed these competitors in 74, 98, and 97%, respectively, of the observed cases of multiple parasitism.Dissection of parasitized host larvae revealed that dead parasite larvae had different fates. Although injured and dead braconid and ichneumonid parasites were encapsulated by aggregations of host lamellocytes, precocious larvae remained unencapsulated, regardless of whether death occurred normally or, rarely, resulted from injury. It is hypothesized that successful avoidance of encapsulation by both precocious and normal larvae ofC. tanytmemusis due to either or both of the host‐produced cyst or the parasite‐produced trophic membrane.The precocious larvae fulfill the requirements for the ultimate altruist predicted by kin‐selection theory. However, because they are genetically identical to the individuals whose survival they enhance, the precocious larvae paradoxically qualify as a completely selfish caste as well. It is thus pointed out that the biological role of the precocious larvae is most appropriately evaluated as that of defender.
Assimilation and deposition of wax esters in planktivorous seabirds
Authors: Roby Daniel D. , Place Allen R. , Ricklefs Robert E. 
Published: June 2005

AbstractWe have analyzed the lipid composition of meals fed to chicks and determined the ability of chicks to assimilate wax esters in four species of high latitude, plankton‐feeding seabirds: one alcid (Aethia pusilla; Alcidae: Charadriiformes) and three petrels (Pelecanoides urinatrix, P. georgicus, and Pachyptila desolata; Procellariiformes). Up to 63% of the estimated digestible energy in chick meals consists of wax esters. Using 14C‐labeled cetyl palmitate, we have shown that chicks of the four study species efficiently hydrolyze wax esters, with less than 1% of the ingested label excreted in most cases. Labeled fatty acids were assimilated and deposited primarily as triacylglycerols in storage fat depots. The one study species known to store lipids in the proventriculus retained much of the labeled wax ester unhydrolyzed in stomach oils. However, the capacity to store stomach oils was not a requisite for efficient assimilation of wax esters. This study provides the first direct evidence that seabirds have the inherent ability to digest and assimilate wax esters efficiently.
Variations in radiosensitivity during development of the frog Limnodynastes tasmaniensis
Authors: Panter H. C. 
Published: June 2005

AbstractTwenty‐two stages of the life cycle of the laboratory‐reared frog Limnodynastes tasmaniensis, from the fertilised egg to the adult frog, have been subjected to acute irradiation from cobalt‐60 (60Co) gamma rays to determine the lethal dose (LD50) values. The period of observation was 40–160 days, depending on the stage irradiated. The most sensitive stage was the fertilised egg, with an LD50/40 of 0.6 Gy. Thereafter, radioresistance increased in an uneven pattern, with periods of relatively rapid increase alternating with periods of little change. The most resistant stages of the life cycle were medium to large tadpoles at limb bud and toe development stages (LD50/60 ∼ 25 Gy). At metamorphosis, resistance decreased significantly to an LD50/160 of 18.3 Gy, with a very similar result, 18.7 Gy, for young adult frogs. The latter figure, when compared with LD50 values for other frogs, is found to be in good agreement with other results obtained using gamma rays. Preliminary experiment on chronic caesium‐137 (137Cs) gamma irradiation are described.
Immunocompetence in Hydra: Epithelial cells recognize self‐nonself and react against it
Authors: Bosch Thomas C. G. , David Charles N. 
Published: June 2005

AbstractThe evolution of effective immunologic defense mechanisms in multicellular organisms involves the ability of host cells to distinguish betweeen “self” and “nonself” and to react appropriately to eliminate foreign tissue. By producing interspecies grafts we have obtained evidence that immunorecognition followed by incompatibility reactions occur in Hydra. Our results demonstrate that epithelial cells of Hydra recognize and phagocytose foreign hydra cells, indicating that they are the effector cells in the incompatibility reactions. This observation is consistent with the idea that immunocompetence appeared early in the evolution of multicellular organisms.
Induction of sea cucumber oocyte maturation by starfish radial nerve extracts
Authors: Maruyama Yoshihiko K. 
Published: June 2005

AbstractCross‐reactivity of maturation‐inducing factors was studied between sea cucumbers and starfish. Radial nerve extracts from both sea cucumbers and starfish induce maturation in ovarian oocytes associated with follicle cells but not in follicle‐free oocytes. Radial nerve extracts of sea cucumbers did not induce maturation in ovarian oocytes or follicle‐free oocytes of starfish. In contrast, radial nerve extracts of starfish induce maturation of both ovarian oocytes and follicle‐free oocytes of sea cucumbers. Based on protease sensitivity and elution patterns on Sephadex G‐15 or G‐50 columns, the active factor from starfish radial nerve extracts appears to be peptides similar in molecular weight to starfish gonad‐stimulating substance (GSS). Additionally, 1‐MeAde, a non‐species‐specific maturation‐inducing substance in starfishes, had no maturation‐inducing effects on sea cucumber oocytes. It was concluded that starfish radial nerve extracts contain a substance(s) which induces maturation of sea cucumber follicle‐free oocytes, and sea cucumber oocytes maturation is regulated by substances different from those in starfish.
Morphogenetic movements and a provisional fate map of development in the holostean fish Amia calva
Authors: Ballard William W. 
Published: June 2005

AbstractCell‐marking experiments using the vital dye Nile blue sulfate have shown that in embryos of the holostean fish Amia calva the first cleavage plane is normally the plane of bilateral symmetry, that no significant “in‐turning” of presumptive mesoderm occurs at the germ ring or terminal node, and that cells destined for the heart, head mesoderm, and foregut derivatives (adhesive organs and pharynx) are located near the animal pole already in late cleavage stages, rather than brought there by morphogenetic movements.As in teleosts, cells destined for the central nervous system (CNS), the first few somites, and also the kidneys and their longitudinal ducts are put in place directly by convergence of subsurface cells from less than the dorsal half of the blastoderm through the embryonic shield. While this is being completed the rest of the somite mesoderm is delivered to the body axis by convergence along the germ ring, which it has reached by earlier obliquely epibolic movements of internal cells.The outermost epithelium of the embryo moves chiefly by epibolic stretching and does not contribute significantly to any internal organ. Dye marks placed upon external cells of the rim of the germ ring or the terminal node remain there throughout epiboly, and those placed anterior to either the rim or the node fail to reach these. When dye carriers are placed upon the outer epithelium their dye is not only held within its cells, but by diffusion it is also brought to deeper cells that are destined for mesodermal and nervous structures. The convergent movements of these deeper cells tend to disengage them from the stained epithelium that originally covered them.The hindgut is apparently formed by the posterior hypoblast, a few cells of which may from time to time be seen from the outside of the embryo, protruding beyond some sector or other of the germ ring epiblast. The trunk‐tail bud is assembled as in teleosts by extension of the CNS, the notochord, the hindgut, and the primitive kidney ducts from the embryonic shield and also by the convergence of internal cells along the germ ring and from the mesodermal areola that is left by its closure.Rough charts of the morphogenetic movements before the major phase of differentiation and a first approximation of a fate map for Amia are presented. There is a discussion of the similarities and differences of these in comparison with those of teleosts and amphibia.
Characterization of the secretory proteins of rat preputial gland in relation to urinary proteins
Authors: Langeland Astrid 
Published: June 2005

AbstractThe water‐soluble proteins of the rat preputial gland secretion were characterized in native and SDS‐treated form on polyacrylamide gel electrophoresis. Nine major proteins were present in the secretion. One protein was a glycoprotein of molecular weight greater than 200,000 with β‐glucuronidase activity, and the other eight proteins had a molecular weight of 17,000, but with different charges. Acid phosphatase and arylsulphatase activities were present in the secretion in minor amounts. The isoelectric points of the secretory proteins ranged from 8.5 to 5.3; none of the proteins were lipoproteins, and there were no sex differences. The male and female rat urinary proteins were also characterized electrophoretically. The male rats had two different protein patterns, probably genetically determined. The female rats showed basically one urinary protein pattern, but their urines were frequently mixed with the preputial gland secretory proteins, which most likely played a part in the chemical communication. The mixing could not be correlated to daytime or estrous cycle.
Gill ammonia transport
Authors: Evans David H. , Cameron James N. 
Published: June 2005

AbstractAmmonia theoretically can traverse the gill epithelium of aquatic animals in a variety of ways. Recent experiments utilizing both whole animals (fish and arthropods), and perfused heads of fishes indicate that diffusional movement of both NH3 and NH4+ takes place, as well as basolateral (serosal) Na+/NH4+ exchange. Data supporting the presence of apical (mucosal) Na+/NH4+ exchange are more equivocal, and there is no published evidence for transport via basolateral NH4Cl + NaCl co‐transport. The relative roles of various pathways may depend upon the species and its salinity of acclimation.
Immunocytochemical demonstration of steroid hormones in the granulosa cells of the medaka, Oryzias latipes
Authors: Onitake Kazuo , Iwamatsu Takashi 
Published: June 2005

AbstractImmunocytochemical identification of steroid hormones was performed in granulosa cells isolated from large ovarian follicles of the medaka. The granulosa cells recovered from daily spawning females, 8.5 h after the onset of light, reacted with anti‐progesterone and anti‐17α‐hydroxyprogesterone antibody, while the granulosa cells treated 2.5 h after the onset of light did not. After 6 h stimulation with gonadotropin (PMS) in vitro, the isolated granulosa cells reacted with anti‐progesterone antibody. The granulosa cells examined 8.5 h after the onset of light did not react with anti‐estradiol or antiestriol antibody.These results demonstrate that, in Oryzias latipes, progestins (progesterone and 17α‐hydroxyprogesterone) are synthesized in the granulosa cells which are directly stimulated by gonadotropin.
Characterization of macrophages in the tail of the anuran tadpole
Authors: Nishikawa Akio , Yoshizato Katsutoshi 
Published: June 2005

AbstractMacrophage‐like cells in the tail mesenchyme of bullfrog tadpoles were isolated and characterized. These cells actively ingested latex beads into their perinuclear cytoplasm and thyroid hormone was essential for their survival in vitro. The requirement for this hormone is a unique property of these cells since other types of tail cells, such as epidermal cells and mesenchymal fibroblasts, are unable to survive in the presence of the hormone. The unusual characteristics of the cells suggest that they are indeed phagocytic macrophages and that they play a crucial role in the thyroid hormone‐dependent breakdown of the tail.
Membrane activity and its correlation with vacuolar contraction in the heliozoan Echinosphaerium
Authors: Nishi Takako , Kobayashi Makoto , Shigenaka Yoshinobu 
Published: June 2005

AbstractMembrane potentials were recorded from two species of Heliozoa, Echinosphaerium akamae and E. nucleofilum. The resting potential ranged from −20 to −50 mV with an average value of −33.7 ± 12.9 mV (± SD, n = 10) and −31.6 ± 9.5 mV (± SD, n = 10) in E. akamae and E. nucleofilum, respectively. Action potentials were elicited spontaneously or in response to applied current. They were abolished in Ca2+ ‐deficient solution with no effect by Na+ or Mg2+, indicating Ca‐spikes. Membrane hyperpolarization, which correlated with the contraction of contractile vacuole (H‐CV), was recorded. The onset of hyperpolarization appeared to be simultaneous with the initiation of contraction. The amplitude of H‐CV was dependent on K+ ‐concentration in the external fluid with reduction by increasing K+. The results suggested that H‐CV was caused mainly by the increase in K+ ‐conductance of the membrane with a contribution in part by Cl−.
Neuromuscular properties in serially homologous lobster limbs
Authors: Mearow K. M. , Govind C. K. 
Published: June 2005

AbstractThe lobster Homarus americanus has five pairs of serially homologous thoracic limbs, the most anterior being the paired chelae followed by four pairs of walking limbs (WLs). We have examined the opener and closer muscles of the WLs in terms of their fiber composition, axonal branching pattern, and synaptic properties. The opener muscle is similar in these serially homologous limbs being composed of all slow fibers. The closer muscle, however, differs in fiber composition amongst the limbs. In the small, nonchelate 3rd and 4th WL, it consists of only slow fibers, while in the much larger, chelate 1st and 2nd WL it has 40% fast and 60% slow fibers. In the chelae, which are bilaterally asymmetric, the closer muscle is known to consist of 70% fast and 30% slow fibers in the cutter chela and all slow fibers in the crusher chela. These differences in the closer muscle reflect differences in the function of the thoracic limbs. Differentiation in the serially homologous limbs occurs to a lesser extent in the pattern of axonal branching and excitatory innervation. Thus bifurcation of the motor axons into two primary branches each supplying one‐half of the bipinnate muscle is found in the anterior limbs but tends to disappear in the most posterior limb. Fast axon synapses are more prevalent in the closer muscle of the 1st WL than in the 4th WL. Such differences in distribution between 1st and 4th WLs are also found for the single excitor axon synapses to the opener muscle.
Distribution of interstitial retinol‐binding protein (IRBP) in the vertebrates
Authors: Bridges C. D. B. , Liou G. I. , Alvarez R. A. , Landers R. A. , Landry Andre M. , Fong S.‐L. 
Published: June 2005

AbstractImmunoblots of interphotoreceptor matrix preparations from 20 species belonging to six vertebrate classes were probed with antibodies against bovine interstitial retinol‐binding protein (b‐IRBP). Each preparation displayed an immunoreactive protein band. In the Osteichthyes, the apparent Mr of this band was 67,600 ± 2,700 (x̄ ± SD, n = 8). In two of the Osteichthyes, the band was resolved into a closely spaced doublet. Including previously published data for five mammals and one amphibian, species from the other classes (Chondrichthyes, one species; Amphibia, four species; Reptilia, one species; Aves, one species; Mammalia, nine species) had IRBPs with Mr that averaged 2.0 times that of the Osteichthyes, namely 134,200 ± 8,600 (x̄ ± SD, n = 17). Frog IRBP was very similar to mammalian IRBP in terms of its immunohistochemical distribution (determined with rabbit anti‐frog IRBP antibodies), its molecular weight (sodium dodecyl sulfate polyacrylamide gel electrophoresis and gel‐filtration chromatography), retinol‐ and concanavalin A‐binding ability, and because it was synthesized and secreted in vitro by the isolated retina but not by the pigmented layers of eye. Goldfish IRBP apparently binds exogenous (3H)‐retinol but does not bind concanavalin A and has about half the Mr of frog IRBP. The occurrence of IRBP‐like proteins crossreacting with anti b‐IRBP antibodies in the interphotoreceptor matrix of all six major vertebrate classes is consistent with the hypothesis that IRBP is an important element in the vertebrate visual cycle.
Assisted fertilization by zona drilling: A mouse model for correction of oligospermia
Authors: Gordon Jon W. , Talansky Beth E. 
Published: June 2005

AbstractA micromanipulation apparatus was used to produce holes in the zonae pellucidae of unfertilized mouse oocytes. A microneedle loaded with acid Tyrode's solution was brought into contact with the zona surface, and positive flow was used in conjunction with mechanical pressure to cause a localized dissolution of the zona. Treated eggs were then fertilized in vitro in comparison with control cells. The zona drilling procedure decreased the sperm count required to achieve fertilization by a factor of approximately 100. The rate of polyspermy in zona‐drilled oocytes was not greater than in controls, and oocytes fertilized after drilling, when implanted into pseudopregnant foster females, developed to term at the same rate as controls. The results demonstrate that zona drilling is a safe, effective method of increasing the efficiency of fertilization in vitro and may be useful both in agriculture and medicine for conferring fertility upon males with low sperm counts.