bluuebunny/crossref_metadata_2025 huggingface dataset:
Cold shock damage is due to lipid phase transitions in cell membranes: A demonstration using sperm as a model
Authors: Drobnis Erma Z. , Crowe Lois M. , Berger Trish , Anchordoguy Thomas J. , Overstreet James W. , Crowe John H.
Published: June 2005

When cells are cooled to temperatures above the freezing point of water at rates greater than a few degrees per minute, they sustain irreversible injury. Reduction of this “cold shock” damage could increase the survival of animals and plants at low environmental temperatures and improve the cryopreservation of plant and animal cells. Leakage of solutes across membranes, associated with thermotropic phase transitions in membrane lipids, is thought to be responsible, but this hypothesis has not been tested directly. Using Fourier transform infrared spectroscopy (FTIR), we measured the lipid phase transitions in intact, living sperm, the animal cell in which cold shock has been studied most extensively. A shift in the CH2 absorbance peaks indicates the transition from liquid‐crystalline to gel phase. The phase transition in sperm membranes occurred at a lower temperature for a marine shrimp than for the pig. In each case, potassium leakage, which is a hallmark of cold shock damage, increased abruptly near the end of the phase transition. Human sperm are quite resistant to cold shock, and an abrupt lipid phase transition was not detected. This phase behavior is typical of membranes containing a high proportion of cholesterol, and human sperm have an unusually high sterol content. High cholesterol levels are known to stabilize membranes during cooling. Overall, the lipid phase behavior was consistent with the temperature range over which cooling was damaging for pig and shrimp sperm, and the with the extent of damage produced in pig and human sperm. This is the first direct evidence that cold shock results from lipid phase transitions in cell membranes. © 1993 Wiley‐Liss, Inc.
Physiology and morphology of the cord stretch receptors of the crayfish Cherax destructor
Authors: Savati Fiona , Macmillan David L.
Published: June 2005

The axons of stretch‐sensitive units were located in the isolated nerve cord of the crayfish Cherax destructor. Their physiology and distribution closely resembled that of the tonic and phasic cord stretch receptor (CSR) units of Procambarus clarkii (Grobstein: J. Comp. Physiol., 86:331–348, 1973a), phasic units responding to stretch of the ganglionic cord, and tonic units to stretch of the interganglionic connectives. Removal of the connective tissue sheath did not abolish either response. Small bundles of nerves containing a CSR from the ganglion or connective adjacent to the recording site were backfilled with cobalt. Two common cell types stained, one associated with each physiological result, and we propose that these are the CSRs. Both have cell bodies anteroventrally in the ganglion adjacent to the stretch‐sensitive area and neurites in the same dorsoventral plane as their axons. The neurites of the tonic CSRs are oriented transversely in the neuropile and those of the phasic CSRs longitudinally. We propose that the CSRs are the site of primary stretch activation, that they are either primary sensory neurons with an interneuron‐like structure or interneurons that have acquired a sensitivity to stretch, and that they are activated by connections to cord structures such as those described by Cobb and Heitler (J. Neurocytol., 14:413–426, 1985). We searched for and found no CSRs in the thorax or in the last abdominal ganglion. © 1993 Wiley‐Liss, Inc.
Sporadic appearance of histones, histone‐like proteins, and protamines in sperm chromatin of bony fish
Authors: Saperas Núria , Lloris Domènec , Chiva Manel
Published: June 2005

In this work we study the presence and the composition of 24 species of bony fish, representing 18 families and 7 orders of teleosts. The species studied belonging to orders Clupeiformes and Lophiiformes display typical protamines, whereas the species belonging to orders Notacanthi‐formes, Gadiformes, and Ophiidiformes contain histones instead of protamines in their sperm nuclei. In these species, one or more specific proteins are added to the pattern of canonical histones and, in the cases that have been analysed compositionally (Merluccius capensis, Cataetyx laticeps), the specific proteins seem to be related to histones. Among the order Scorpaeniformes, the species Helicolenus dactylopterus (family Scorpaenidae) presents protamines, whereas Trigla lucerna (family Triglidae) contains histones. Similarly, among the order Perciformes, the species from six families (Percichthyidae, Labridae, Trachinidae, Uranoscopidae, Gempylidae, and Scombridae) have protamines in sperm nuclei and species from two families (Sparidae and Trichiuridae) retain histones and increase the proportion of H1 histone approximately twofold. Two species of Mullus (family Mullidae, order Perciformes) display special proteins with an electrophoretic behaviour corresponding to histone H4 but an amino acid composition more basic.

The results indicate that bony fishes have adopted three main alternatives to condense their nuclear sperm chromatin: namely, protamines, histones, and histone‐like proteins. Moreover, these alternatives do not correspond strictly with phylogeny, favouring the hypothesis that the change “protamine → histone” (or alternatively “histone → protamine”) has occurred independently several times during the evolution of bony fishes. © 1993 Wiley‐Liss, Inc.
Comparison of a fluoresceinated lectin stain with triple staining for evaluating acrosome reactions of dog sperm
Authors: Kawakami Eiichi , Vandevoort Catherine A. , Mahi‐Brown Cherrie A. , Tollner Theodore L. , Overstreet James W.
Published: June 2005

In this study a technique which utilized a fluoresceinated lectin and a fluorescent supravital stain was compared with the conventional triple stain technique for evaluating the viability and acrosomal status of dog sperm. Ten semen samples obtained from 6 normal beagle dogs were evaluated after incubation in vitro with canine capacitation medium. Sperm viability and acrosomal status were assessed at 0, 4, and 7 hours of incubation. Both staining techniques were capable of detecting the increase in spontaneous acrosome reactions which occurs during in vitro capacitation of dog sperm. High positive correlations were observed between the fluorescent stain and the triple stain in the mean values for the percentage of viable sperm and for the percentage of acrosome‐reacted sperm among the viable sperm (r = 0.91, r = 0.97, respectively). However, the fluorescent staining techniques could be carried out much more rapidly than the triple stain technique, and the slides prepared with fluorescent stain were more easily scored because of the higher intensity and greater consistency of staining. These characteristics make the fluoresceinated lectin and the fluorescent supravital stain superior for evaluating acrosome reactions and viability of dog sperm. © 1993 Wiley‐Liss, Inc.
Nightly increase in visual sensitivity correlated with bioluminescent flashing activity in the firefly Photuris versicolor (Coleoptera: Lampyridae)
Authors: Lall Abner B.
Published: June 2005

Changes in visual sensitivity as a function of time‐of‐day were studied in the firefly Photuris versicolor. The electroretinograms (ERGs) elicited by photic stimuli of constant intensity and duration were recorded over long periods (18–52 h) while the insect was in constant darkness. The amplitudes of the ERGs elicited by the standard flash were small and remained constant during the daytime hours and increased on average sixfold during the evening hours, reaching a maximum at the onset of darkness and remaining at that high level until the morning hours. The amplitude of the standard response again was reduced in the morning hours to a daytime low value which again persisted until the following evening (Fig. 1). In addition, a series of flashes of varying intensity were administered periodically and logV/logI curves as a function of time‐of‐day were obtained. Compared to the daytime logV/logI curves, the nighttime curves were shifted about 4 log units towards the left on the intensity axis (Fig. 2). This period of high visual sensitivity was correlated with the species' flashing activity period, which occurs during the night hours (Fig. 1). © 1993 Wiley‐Liss, Inc.
Presence of insulin‐like growth factor binding protein (IGF‐BP) in rainbow trout (Oncorhynchus mykiss) serum
Authors: Niu P.‐D. , Le Bail P.‐Y.
Published: June 2005

Recombinant human IGF‐I (hIGF‐I) binding to rainbow trout serum fractions was studied in vitro. Binding protein preparations, from human and trout serum (hBP and tBP), which were obtained using size exclusion chromatography (AcA 54) under acid conditions, were used to characterize IGF binding protein. Mammalian protein binding assay, using hIGF‐I as labeled hormone, was optimized (pH, Tris concentration, bound‐free 125I‐hIGF‐I separation conditions by charcoal) for trout serum. The association kinetics (T = 4°C) of specific binding presented a plateau from 20–30 h, and nonspecific binding remained stable for the same time. Percentage of 125I‐hIGF‐I which was able to bind to tBP was at least 55%. In the same incubation conditions, hIGF‐I binding to trout BP had a higher affinity (Ka = 2.8 1010 M–1) than those obtained with human BP preparation (Ka = 0.17 1010 M–1) which contains four molecular forms of BPs. The binding was saturable but its capacity was fourfold lower in trout (Bmax = 410 ng/ml of serum) than in human (Bmax = 1868 ng/ml) serum. Binding to trout BP is very specific for human IGF‐I and for trout IGF serum extract. hIGF‐II crossreacts partially but no binding was observed with porcine insulin. When trout serum was chromatographed on an analytic AcA 54 column (1 × 100 cm), the maximum hIGF‐I activity was found in a peak which corresponded to 55 kDa. Two other peaks (34 and 23 kDa) also bound hIGF‐I, but with a much lower activity. In Western‐ligand‐blot from SDS‐PAGE, binding of 125I‐hIGF‐I to trout serum presented a major band (MW = 41.5 kDa) similar to the biggest form of IGF‐BP‐3 from human serum. These results suggest that IGF binding protein(s) exists in trout serum but the majority of IGF binding activity is carried only by one form (41.5 kDa), in contrast to mammals which have four forms of BP with a similar magnitude of serum concentration. © 1993 Wiley‐Liss, Inc.
Effect of T3 or T4 challenge on inner‐ and outer‐ring deiodination of T3 and T4 in the liver, kidney, and gill of rainbow trout, Oncorhynchus mykiss
Authors: MacLatchy Deborah L. , Eales J. G.
Published: June 2005

The effects of feeding 3,5,3′‐triiodo‐L‐thyronine (T3)‐ and L‐thyroxine (T4)‐supplemented diets for 3 days on the plasma T3 and T4 concentrations and on the plasma outerring (5′D) and inner‐ring (5D) deiodination of T4 and T3 were studied in vitro for the liver, gill, and kidney of rainbow trout (Oncorhynchus mykiss) at 12°C. Trout were sampled 24 hr after their last meal. T3 treatment increased plasma T3 but did not alter plasma T4. T4 treatment did not alter plasma T3 or T4. In untreated trout, T45′D activity to form T3 occurred in all 3 tissues; T45D activity to form 3,3′,5′‐T3 (rT3) was not significant, T35D activity to form 3,3′‐T2 (diiodo‐L‐thyronine) was low, and T35′D activity to form 3,5‐T2 was barely detectable. A low‐Km T45′D (T4 concentration = 0.65 nM) was confirmed in liver and gill, and a high‐Km T45′D (T4 concentration = 12 nM) was confirmed in liver and kidney. For liver, T3 feeding depressed both low‐Km and high‐Km T45′D isozymes, but induced T45D and T35D; T4 feeding depressed only the high‐Km T45′D and increased T35′D slightly. For gill, T3 feeding depressed the low‐Km T45′D and induced T45D; T4 feeding increased T35′D. For kidney, T3 feeding depressed the high‐Km T45′d and induced T35′D; T4 feeding depressed the high‐Km T45′D and increased T35′D. We conclude that in response to either a T3 or a T4 challenge, trout tissues employ several T3 homeostatic mechanisms. Responses to a T3 challenge included (1) depression of both low‐Km and high‐Km T45′D activities to decrease production of T3, (2) elevation of T45D activity to direct T4 substrate to rT3, and (3) elevation of T35D activity to degrade T3 to 3,3′‐T2. In contrast, responses to a 4‐fold greater dietary T4 challenge were restricted primarily to depression of high‐Km T45′D activity in the liver and kidney. © 1993 Wiley‐Liss, Inc.
In vitro exposure of frog (Rana pipiens) pituitaries to gonadotropin‐releasing hormone results in a persistent stimulation of gonadotropin biosynthesis
Authors: Stamper Debra L. , Licht Paul
Published: June 2005

To further investigate the action of gonadotropin‐releasing hormone (GnRH) on gonadotropin (Gth) secretion and synthesis, pituitaries from frogs, Rana pipiens, were incubated in the presence or absence of 100 ng/ml GnRH for 12 h. GnRH was then removed from the medium and glands were labeled with 35S‐methionine either 12, 24, or 36 h after the conclusion of GnRH exposure. Immunoassayable LH and FSH (iLH and iFSH; both labeled and nonlabeled hormone) were determined by separate radioimmunoassays. Newly synthesized (radiolabeled) Gth was quantified by immunoprecipitation. When GnRH was present in the medium, it stimulated the secretion of both iLH and iFSH (compared to unexposed glands). Following withdrawal of the secretagogue, iLH and iFSH secretion diminished until they returned to control levels (within ca. 12 h). Previous exposure to GnRH enhanced the biosynthesis of Gth; this elevation was detectable up to 36 h after removal of the secretagogue. The magnitude of the elevation in Gth synthesis did not diminish with time, as secretion had, but remained constant. Gth synthesis was comparable in glands that had been exposed to GnRH 12 h and those exposed to the secretagogue 36 h prior. Thus, the GnRH‐induced elevation in Gth secretion and synthesis can be dissociated; the elevation in synthesis is more chronic than the elevation in secretion. © 1993 Wiley‐Liss, Inc.
Dual origin of yolk nuclei in the lesser spotted dogfish, Scyliorhinus canicula (Chondrichthyes)
Authors: Lechenault Henri , Mellinger Jean
Published: June 2005

Using plastic embedding techniques and semithin sections in order to overcome the difficulties encountered in the sectioning of yolky eggs, we made a histological study of the developing blastodisc and early embryo of the oviparous dogfish Scyliorhinus canicula (L.) (Pisces: Chondrichthyes) from Roscoff (Brittany, France). According to our observations, several conclusions based on classical studies on elasmobranch development have to be revised as follows: (i) Cleavage of the germinative disc into blastomeres lags considerably behind the mitotic activity of diploid nuclei derived from amphimixy. As a result, the number of surface blastomeres does not correspond in any way to the actual number of nuclei, even at the start of segmentation. Thus, segmentation is primarily syncytial. (ii) The first set of yolk nuclei corresponded to the deepest nuclei that remained beneath the segmentation cavity after complete cellularization of the blastodisc. They became polyploid, some of them degenerated, and the others multiplied while remaining close to the extraembryonic endoderm during epiboly. (iii) A second set of yolk nuclei was derived from the embryonic endoderm along its boundary with the extraembryonic endoderm. Endoderm cells escaped into the yolk layer nearby. They then give off free nuclei, which also became very large and finally were indistinguishable from the first set. (iv) No yolk nuclei were derived from supernumerary sperm nuclei, even when the latter were able to divide several times in synchrony. Nuclei from this haploid lineage were always smaller than those in the first set, and they were finally located in the deepest layer of the germinative disc, where they degenerated. It is concluded that this chondrichthyan fish generates its yolk syncytium in a very different way from teleosts, in which all yolk nuclei are derived from the blastodisc. © 1993 Wiley‐Liss, Inc.
Physiology and central projection of auditory receptor cells in the prothoracic ganglion of three closely related species of bushcrickets (Tettigoniidae, insecta)
Authors: Ahi Janak , Kalmring Klaus , Ebendt Rüttger , Hellweg Judith
Published: June 2005

A comparative study was made of the projection patterns of functionally and morphologically identified auditory receptor cells of the complex tibial organ in the forelegs of three closely related Decticine species. A combined recording and staining technique was used, with subsequent histological examination and morphometric measurements. Adult males and females of the species Psorodonotus illyricus, Decticus albifrons, and Decticus verrucivorus, were chosen for this investigation. No species‐specific differences were found in the projection patterns of receptor cells that belonged to the same or similar functional classes in the three species. The cells also occupied the same target areas within the neuropile. A significant overlapping of the projections of the different receptor cells within the neuropile of the anterior ring tract (aRT) was revealed, in particular of those cells that were tuned to characteristic frequencies within similar frequency bands. © 1993 Wiley‐Liss, Inc.
Recovery of viability in triploid hybrids between Japanese and European water frogs, and their reproductive capacity
Authors: Ohtani Hiromi , Kondo Yasuyuki
Published: June 2005

Diploid and triploid hybrids, consisting of the various combinations of chromosome set and cytoplasm between Rana nigromaculata and Rana lessonae, were generated in order to study their viability and reproductive capacity. Reciprocal diploid hybrids and allotriploids, which had two lessonae genomes and one nigromaculata genome in nigromaculata cytoplasm, all died without closing their neural folds. Allotriploids, which had two nigromaculata genomes and one lessonae genome in nigromaculata cytoplasm, all grew into healthy mature males in 12.4% (21 frogs) of zygotes. Following the elimination of lessonae chromosomes, ten of these males produced many spermatozoa containing a haploid set of nigromaculata chromosomes. Other allotriploids, which had either one nigromaculata genome and two lessonae genomes or two nigromaculata genomes and one lessonae genome in lessonae cytoplasm, exhibited slightly improved viability. © 1993 Wiley‐Liss, Inc.
Stimulation of oxidative metabolism by thyroid hormones in propranolol/alloxan‐treated bony fish, Anabas testudineus (Bloch)
Authors: Peter M. C. Subash , Oommen Oommen V.
Published: June 2005

The specific activities of oxidative enzymes, in response to 3,5,3′ triiodo‐L‐thyronine (T3) and L‐thyroxine (T4) administration, were assayed in the teleost, Anabas testudineus pretreated with the beta adrenergic antagonist, propranolol, and the beta islet cell cytotoxin, alloxan. Administration of propranolol or alloxan decreased the activity of cytochrome oxidase, succinate dehydrogenase (SDH), mitochondrial adenosine triphosphatase (Mg2+ ATPase), lactate dehydrogenase (LDH), and cytosolic malate dehydrogenase (cMDH) and did not change that of α‐glycerophosphate dehydrogenase (α‐GPDH) and glucose‐6‐phosphate dehydrogenase (G‐6‐PDH). Propranolol treatment decreased and alloxan administration did not change the mitochondrial MDH (mMDH) activity. A single injection of T3 or T4 significantly stimulated cytochrome oxidase and oc‐GPDH activities, and decreased Mg2+ ATPase, cMDH, and mMDH activities but did not affect SDH, G‐6‐PDH, or LDH. The activity of cytochrome oxidase, oc‐GPDH, SDH, and Mg2+ ATPase was increased by T4 or T3 injection into propranolol or alloxan‐treated fish. The data suggest that in teleosts, the stimulatory effect of thyroid hormones on oxidative metabolism is not mediated through the potentiation of adrenaline or insulin action. © 1993 Wiley‐Liss, Inc.
Stimulatory effect of fractions of brain homogenate on protein synthesis in ovaries of Eisenia fetida Sav. In Vitro (Oligochaeta, Annelida)
Authors: Lattaud C. , Marcel R.
Published: June 2005

In Eisenia fetida, during the period of genital activity, the synthesis of androgen by testicular tissues is under the control of a neurohormone elaborated by cerebral ganglia (CG). These ganglia also have a trophic effect on ovarian protein synthesis. Present results confirm that incorporation in vitro of [3H]‐leucine by ovaries is stimulated by a cerebral neurohormone. Furthermore, fractions of brain homogenate, obtained by gel filtration on Sephadex G 25, have the same action on ovaries in organ culture as CG. Two specific fractions (fractions 3 and 4) stimulate protein synthesis in the ovary. In the ovarian oocytes, the rate of vitellogenesis is low, since in cultured isolated ovaries the amount of radioactive precursor incorporated is only 0.06% of the amount added and this percentage remains low in the ovaries cultured with fractions 3 and 4 (0.15% and 0.21%, respectively) or with CG (0.24%). Further research is necessary to obtain and characterize the biologically active material. © 1993 Wiley‐Liss, Inc.
Metamorphosis‐dependent recognition of larval skin as non‐self by inbred adult frogs (Xenopus laevis)
Authors: Izutsu Yumi , Yoshizato Katsutoshi
Published: June 2005

Larval cells in tissues of the anuran tadpole are replaced by adult cells in the corresponding tissue of the frog during metamorphosis. As an extreme example of such replacement, tissues of the tail, which have no counterpart in the adult, are completely eliminated during metamorphosis. We postulated that some immunological recognition mechanism might be involved in this specific elimination of the tail tissue. Our working hypothesis was tested by applying the skin transplantation technique to individuals of the inbred J strain of Xenopus laevis, which accept homografts. We demonstrated that young adults reject skin grafts from larvae. This rejection was immunological in nature because the secondary response of rejection was observed. There was a clear difference in graft rejection between grafts from the tail and those from the body. Grafts of tail skin were rejected irrespective of the metamorphic stages of donors. By contrast, grafts of body skin became acceptable as donors metamorphosed. The mean survival time of the larval skin was much longer than that of major histocompatibility complex (MHC)‐disparate skin grafts reported by other investigators, suggesting that the rejection described in the present study is due to disparity in minor histocompatible (minor‐H) antigens. We propose the involvement of the immunological recognition mechanism in the process of specific detection and elimination of larval cells in the tail. © 1993 Wiley‐Liss, Inc.
Physiological response of Zebu and Taurine oxen to draught work
Authors: Zanzinger Johannes , Becker Klaus , Rometsch Martin
Published: June 2005

Four Zebu and four Simmental oxen were submitted to continuous and to graded draught work. Venous blood samples were taken before, during, and after exercise at intervals of 2–5 min. Anaerobic threshold was reached at a draught power of 1.6 ± 0.06 kW for Zebu and 0.7 ± 0.07 kW for Simmental. Corresponding plasma lactate concentrations were 1.7 ± 0.2 mmol/liter and 1.6 ± 0.3 mmol/liter, respectively. Partial pressure of oxygen (pvO2), carbon dioxide (pvCO2), and plasma free fatty acids (FFA) during and after work differed between breeds (P ∼ .001) and individuals (P ∼ .05). After work, an up to 8‐fold increase in FFA was found. Highest plasma lactate concentrations during continuous maximal draught were 3.75 ± 1.76 (Zebu) and 6.01 ± 0.88 mmol/liter (Simmental). Acid‐base‐state during and after exhaustive work remained stable. Heart rate in both breeds did not exceed 190 min−1. It is concluded that 1) even during heavy draught work, anaerobic energy formation plays a minor role for cattle, 2) fatigue in working oxen may be related to cardiovascular limitations, and 3) the physical fitness of European beef‐breed oxen is lower compared to multipurpose African Zebu oxen. © 1993 Wiley‐Liss, Inc.
Comparison of hemolymph lipoproteins from four species of crustacea
Authors: Komatsu Masaharu , Ando Seiichi , Teshima Shin‐Ichi
Published: June 2005

Two different lipoproteins, lipoprotein I and very high density lipoprotein (VHDL), were isolated from the male hemolymphs of freshwater prawn, mitten crab, and striped stone crab by a different density gradient ultracentrifugation. Lipoprotein II as well as lipoprotein I and VHDL was further found in the female hemolymphs of these crustacea. Lipoprotein II seemed to be a vitellogenin and spawned kuruma prawn without eggs lacked lipoprotein II in their hemolymph. The densities of lipoprotein I varied between 1.12 and 1.18 g/ml reflecting the difference of protein‐lipid ratio. In contrast lipoprotein II and VHDL had approximately constant densities of 1.19—1.21 g/ml and 1.26—1.27 g/ml, respectively. Lipoprotein I, lipoprotein II, and VHDL isolated from the crustacean hemolymph contained phospholipid as a predominant lipid component. Crustacean lipoprotein was divided into the freshwater type and the seawater type. Freshwater prawn and mitten crab classified into the freshwater type tended to have high protein concentrations in lipoprotein I and VHDL. In contrast both lipoprotein I and VHDL protein concentrations from kuruma prawn and striped stone crab, which were classified into the seawater type, were much lower than those from the freshwater type. Lipoprotein I from freshwater prawn and mitten crab had two major apolipoproteins with apparent molecular weights of 230,000 and 100,000, and 340,000 and 100,000, respectively, while lipoprotein I from kuruma prawn and striped stone crab consisted of three major apolipoproteins (molecular weights 180,000, 100,000, and 80,000). VHDL found for the first time in crustacea probably plays an important role in lipid transfer reaction between lipoproteins. © 1993 Wiley‐Liss, Inc.
Effects of insulin on the glucose uptake by the thyroid gland of the turtle Chrysemys dorbigni acclimated to different temperatures
Authors: Machado Vera L. A. , Marques Maria
Published: June 2005

Insulin stimulation of the glucose uptake by the thyroid gland of the turtle (Chrysemys dorbigni) has been previously reported. The aim of the present study was to examine the influence of different temperatures (6, 25, or 36°C) on this effect. Insulin‐stimulated glucose uptake was evident when turtles were acclimated for 15 days at 25° or 36°C, and their glands studied at the respective temperatures. In glands from turtles acclimated at 6°C, this effect was only seen when the preincubation and incubation time was extended from 60 to 300 min. The findings show that in this ectotherm species (1) the insulin effect is temperature dependent, and (2) can be expressed at very low temperature. © 1993 Wiley‐Liss, Inc.
In vitro release of lectins from Phallusia mamillata hemocytes after their fractionation on a density gradient
Authors: Cammarata Matteo , Parrinello Nicolo , Arizza Vincenzo
Published: June 2005

Hemocytes were fractionated by centrifugation on a discontinuous Percoll density gradient from the hemolymph of Phallusia mamillata. Results obtained from microcultures of the fractionated hemocytes, sugar‐inhibition experiments, SDS‐PAGE, and immunoblotting indicate that “compartment cells” release cellular‐type (CL) lectins that are specific for α‐lactose and lactulose. The released lectins have the same properties as the CL lectins that were previously isolated from sonicated unfractionated hemocytes, but they differ in terms of some molecular and immunological properties from the lectins (SL) purified from the serum. SLs were never found in the supernatants from microcultures of the fractionated hemocytes. © 1993 Wiley‐Liss, Inc.
Immunological detection of an oviductal glycoprotein in the rat
Authors: Abe Hiroyuki , Abe Miki
Published: June 2005

In the golden hamster, high‐molecular‐weight glycoproteins are secreted by the epithelial cells of the oviduct. The present study was designed to investigate the possibility that the rat oviduct produces specific glycoproteins similar to the oviductal glycoproteins (GHOGPs) of the golden hamster. Oviductal extracts and oviductal fluids obtained from ovulatory rats were analysed by immunoblotting for the presence of glycoproteins that cross‐react with a monoclonal antibody (MAb) against GHOGPs. The MAb immunoreacted with a broad band of proteins with a range of molecular weights (MWs) of above 330 kD in oviductal extracts or oviductal fluid after fractionation by electrophoresis under reducing conditions, but these proteins were not present in serum and uterine flushings. An immunohistochemical study demonstrated that the MAb bound strongly to the epithelial cells of the oviduct and, to a lesser extent, to those of the large intestine. Weak reactions were also observed with some other tissues. However, similar material of high MW was not detected in extracts of tissues from the other organs, suggesting that the glycoprotein of high MW that reacted with the MAb is specific for the oviduct. Ultrastructural immunocytochemistry revealed that the MAb reacted specifically with putative secretory granules of nonciliated cells in the oviductal epithelium. These results indicate that the oviductal epithelial cells of the rat produce a specific glycoprotein that is immunologically similar to GHOGPs. © 1993 Wiley‐Liss, Inc.
Endocrine regulation of the elasmobranch reproductive tract
Authors: Callard Ian P. , Koob Thomas J.
Published: June 2005

Although the rich variety of reproductive tract adaptations in elasmobranchs has been well documented and involves many variants associated with oviparity and extensive evolution of viviparity in the group, little is known of the hormone dependence of reproductive tract development, differentiation, and function in the adult. In this paper, we present a brief review of some of our observations on the subject made over the past 15 years in the context of earlier observations. In total, despite the paucity of information, the observations suggest that hormonal mechanisms of reproductive tract regulation, considered until recently to be the priority of mammals, have been in place since the era of very early vertebrate evolution, 400 million years before present. These reinforce the view that the endocrine regulatory mechanisms of reproduction in elasmobranchs may serve as models for more highly evolved mammalian species including the human. Indeed, the enormous variety of reproductive tract adaptations in elasmobranchs foreshadows those subsequently evolved in mammals, and because of transitional stages provide needed insight into process which is not possible in the study of mammals alone. © 1993 Wiley‐Liss, Inc.
Pregnancy in chiroptera
Authors: Rasweiler John J.
Published: June 2005

As with other aspects of their biology, bats exhibit considerable diversity in their reproductive characteristics. While early embryonic development in many species generally adheres to the pattern shown by more commonly studied eutherian mammals, others demonstrate advanced development in the oviduct (to the zona‐free blastocyst stage) and a prolonged tubal journey of the embryo in a temporal sense. In some bats, the process for transporting ova through the oviducts can distinguish between living embryos and the remnants of dead ova. Implantation in bats is unusually diverse with respect to localization of the nidation sites (which in most species seem to be predetermined), orientation of the inner cell mass during implantation, depth of implantation, and trophoblastic invasiveness. Some species which can be bred in captivity would appear to be promising experimental models for studies of implantation because both this process and their endometrial biology in general exhibit many similarities to those of humans. Depending upon the species, bats develop either endotheliochorial or hemochorial placentas. Studies on black mastiff bats (Molossus ater) indicate that maternal endometrial endothelial cells probably play a very important morpho‐genetic role during placental development in this species. Similarities in placental structure suggest that this may also be the case in a number of other eutherian mammals. © 1993 Wiley‐Liss, Inc.
Implantation: A cell biological paradox
Authors: Denker H.‐W.
Published: June 2005

Implantation initiation in eutherian mammals requires, at least in invasive types of implantation, that 1) the trophoblast or subpopulations of it have reached a state of “invasiveness” and, synchronously, 2) the endometrium has reached a state of “receptivity” (“implantation window”). The cell biological basis of “receptivity” as well as of “invasiveness” has long remained unknown, but recently it appears that the application of modern concepts of cell and developmental biology is opening new views of it, concentrating on cell adhesion and cell polarity phenomena.

Implantation initiation requires that the trophoblast attaches via its apical plasma membrane to the apical plasma membrane of the uterine epithelium. Since apical plasma membranes of epithelia are normally non‐adhesive, this represents a cell biological paradox. In development, cells can express two major phenotypes and switch between these: 1) the mesenchymal/fibroblastoid phenotype that is compatible with cells moving individually; 2) the epithelioid phenotype which is characterized by cells expressing apico‐basal polarity and a strong association with neighbouring cells via various junctions, so that they can migrate as sheets but not as individual cells. Application of this concept to embryo implantation would seem to lead to the hypothesis that the trophoblast of blastocysts has to give up part of its typical epithelial organization when becoming invasive; it must express cell‐cell adhesion molecules or matrix receptors non‐typically at its apical plasma membrane, change the spectrum of expressed adhesion molecules, and alter its motility apparatus. This applies in a somewhat similar way to the uterine epithelium at “receptivity.” Interestingly, recent data show that a substantial number of differentiation parameters of these cells change in addition. It appears that part of the epithelial differentiation program is down‐regulated at this phase. This also suggests interesting new aspects of the basis of steroid hormone action at the endometrium, as well as of trophoblast invasiveness, possibly involving switches in the activity of regulatory “master” genes as are also involved in decision making during development. © 1993 Wiley‐Liss, Inc.
Ultrastructural and biochemical analysis of the sarcoplasmic reticulum from crayfish fast and slow striated muscles
Authors: Ushio Hideki , Watabe Shugo
Published: June 2005

Ultrastructural and biochemical properties were compared between two types of the sarcoplasmic reticulum (SR), one from the deep extensor abdominal muscle medialis (fast muscle) and the other from the flexor muscle of carpopodite in meropodite (slow muscle) of crayfish Procambarus clarkii. Electron microscopic observations revealed that terminal cisternae of the SR of crayfish fast muscle was well‐developed and contained feet‐like structures. In transverse sections, the SR of slow muscle was tubule‐like in shape and the terminal cisternae of the SR occupied smaller area than those of the fast muscle SR. The fragmented SR obtained from the homogenized fast muscle was poorly separated by ultracentrifugation with a sucrose gradient (25–50%): both vesicles from light and heavy fractions contained terminal cisternae and were connected to transverse tubules via the feet‐like structures. In contrast, the slow muscle fragmented SR could be separated in to the light and heavy fractions, which contained elliptical vesicles and vesicles with the feet‐like structures, respectively. Sodium dodecyl sulfate (SDS)‐polyacrylamide gel electrophoresis and subsequent 45Ca ligand overlay analyses revealed that a 105,000 ( =105 k) Da protein was the major protein in both SRs, which lacked Ca2+‐binding proteins corresponding to vertebrate calsequestrins. On the other hand, peptide‐mapping of the 105 kDa protein in SDS‐gels suggested no difference in the primary structure between fast and slow SR. Ca2+‐ATPase and Ca2+ uptake activities of the fast muscle SR at 20°C were 0.39 μmol Pi/min·mg and 0.57 μmol Ca/min·mg, respectively, which were clearly higher than those of the slow muscle SR, 0.27 μmol Pi/min·mg, and 0.37 μmol Ca/min·mg, respectively.

These results suggest that the SR of crayfish fast and slow muscles were morphologically and enzymatically different, which might partly cause differences in the contractile properties of fast and slow muscles. © 1993Wiley‐Liss, Inc.
The energetics of osmotic regulation in ureotelic and hypoosmotic fishes
Authors: Kirschner Leonard B.
Published: June 2005

The major mechanisms of urea turnover and of active ion transport in osmoregula‐ tory organs are reviewed. Using published values for the molecular flow through these systems it is possible to estimate the energetic cost of osmotic regulation in hyporegulating marine teleosts and in ureotelic elasmobranchs. Oxygen consumption dedicated to osmotic regulation in the flounder (Platichthys flesus) is about 7 ml kg−1 hr−1 and in the rainbow trout (Salmo gairdneri) 6 ml kg−1 hr−1 For a dogfish (Scyliorhynus canicular) it was 5 ml kg−1 hr−1 and for the skate (Raja erinacea) 5 or 11 ml kg−1 hr−1 based on two values for urea loss by the fish. Both groups of fish used 10–15% of their standard metabolism for osmotic regulation. There are a number of uncertainties that may require modification of these values. It is not known whether TMAO lost by ureotelic regulators is replaced by ingestion or by synthesis. If by synthesis, the cost of regulation would be higher than calculated. Even more serious is the uncertainty regarding the use of organic osmolytes to maintain equilibrium between cells and blood. This strategy almost certainly requires some energy input, but there is insufficient information to permit its quantitative estimation, so the factor was omitted from the calculation. Among hyporegulators the sole unknown is whether the esophagus may absorb some of the ingested salt by diffusion. If so, it would decrease the energy expended in the intestinal tract and lower the total cost of regulation. The conclusion, based on known factors for the species examined, is that both modes are about equally efficient. If it becomes possible to factor in the unknowns it may be that hyporegulation is slightly more economical than ureosmotic. © 1993 Wiley‐Liss, Inc.
Egg capsule structure and permeability in the viviparous shark, Mustelus canis
Authors: Lombardi Julian , Files Tamarah
Published: June 2005

The structure and permeability characteristics of egg capsules of the viviparous matrotrophic elasmobranch Mustelus canis were investigated by scanning electron microscopy (SEM), X‐ray microprobe elemental analysis, and through the use of modified Ussing chambers. The egg capsule surrounds the developing embryo during gestation and consists of a four or more orthogonally arranged laminae of fibrous material. SEM and energy dispersive spectroscopy (EDS) of inner and outer capsular surfaces reveal that the capsule is 4.7 μm in thickness and possesses scattered calcium deposits along its inner and outer surfaces. Transcapsular permeability studies qualitatively demonstrate that capsules are readily permeable to fast green fcf (808 Da) and rose bengal (1,000 Da). Capsules are impermeable to insulin (5, 750 Da), lysozyme (14,300 Da) and bovine albumin (66,000Da). Glucose (P= 3.3 × 10−4 ± 1.2 × 10−4cm/sec[n = 120])and urea(P= 4.5 × 10−4 ± 2.3 × 10−4cm/sec [n = 139]) readily pass across the egg capsules. It is suggested that maternal‐embryonic nutrient transfer primarily involves the transcapsualr passage of low (<5 kDa) molecualr weight components. These data are discussed in relation to the mechanisms of placental attachment in matrotrophic sharks. © 1993 Wiley‐Liss, Inc.
Effects of protease inhibitors on binding of sperm to the vitelline coat of ascidian eggs: Implications for participation of a proteasome (multicatalytic proteinase complex)
Authors: Takizawa Satoshi , Sawada Hitoshi , Someno Tetsuya , Saitoh Yoshiko , Yokosawa Hideyoshi , Hoshi Motonori
Published: June 2005

Among various protease inhibitors, chymostatin (an inhibitor of sperm chymotrypsinlike protease) strongly inhibited the binding of sperm to the vitelline coat of glycerinated eggs of the ascidian Halocynthia roretzi, whereas leupeptin (an inhibitor for sperm acrosin), antipain, and soybean trypsin inhibitor had no significant inhibitory effects. Dansyl‐Val‐Pro‐argininal (an inhibitor of the sperm trypsin‐like protease, spermosin) had an inhibitory effect on the binding of sperm that was much smaller than its effect on fertilization. Since the sperm chymotrypsin‐like protease that is involved in ascidian fertilization has been identified as a proteasome (multicatalytic, proteinase complex), we tested the effects of several peptidyl argininals, inhibitors of the activities of proteasomes, on this binding process. The ranking of the inhibitory effects of these compounds on the binding of sperm was the same as that of their effects on the chymotrypsin‐like activity of the proteasome, reported previously. The potent inhibitors of binding used in these studies had no or minimal effects on sperm motility. These results suggest that a sperm chymotrypsin‐like protease (most probably the chymotrypsin‐like protease in the proteasome) plays a key role in binding of sperm to the vitelline coat of the ascidian egg. © 1993 Wiley‐Liss, Inc.
Significance of circulating catecholamines in regulation of trout splanchnic vascular resistance
Authors: Xu Hao Y. , Olson Kenneth R.
Published: June 2005

It has been generally presumed that circulating catecholamines have little if any effect on systemic vascular resistance in resting trout; however, this question has not been directly addressed. In the present study, the response of isolated vessel rings and perfused tissues to catecholamines and the importance of circulating epinephrine in the vasoconstrictor response of the splanchnic circulation to splanchnic nerve stimulation were examined. Epinephrine (EPI) and norepinephirine (NEPI) produced dose‐dependent contractions of celiacomesenteric (CM) and epibranchial (EB) arteries, anterior cardinal (AC) veins, and increased vascular resistance in the perfused dorsal aorta (PDA; skeletal muscle‐kidney‐distal intestine) and perfused celiacomesenteric (PCM; splanchnic) vascular beds. In all instances the threshold catecholamine concentration for in vitro vasocnstriction was greater than plasma atecholamine concentrations in vivo. Neither EPI nor NEPI contracted ventral aorta rings. Addition of non‐constrictor, but physiological, concentrations of EPI to the perfusate (10‐9M) tripled the increase in PCM resistance produced by splanchnic nerve stimulation. Perfusate EPI also prevented or reversed splanchnic nerve fatigue and restored PCM resistance in fatigued preparations. These results indicate that a direct effect of circulating EPI may be an important source of neuronal catecholamine uptake and may be required to sustain neuronal sympathetic tone. © 1993 Wiley‐Liss, Inc.
Periventricular nucleus lesioning modulates specific somatostatin binding in various brain regions and anterior pituitary
Authors: Sabry Ismail , Suzuki Mitsuo , Shigematsu Kazuto , Kakegawa Tadao
Published: June 2005

The effects of periventricular nucleus (Pe) lesioning on the plasma growth hormone (GH) levels and the anterior pituitary (A.P.) and brain somatostatin (SRIF) receptors were studied. A transient significant increase in plasma GH level in lesioned rats was detected 1 day after the were paralleled by an increase in binding of 125I‐Tyr11‐SRIF‐14 to the A.P. 1 day after lesioning. This result could further confirm that the SRIF inhibitory action on GH release takes place at the A.P. level. Also, a transient increase in binding of the radioligand was detected in some brain areas 1 and 4 days after the lesion. However, the mechanism by which this increase takes place remains to be elucidated. © 1993 Wiley‐Liss, Inc.
Inter‐ and intraspecific distribution of an antigenic epitope found in an inbred strain of the Medaka, Oryzias latipes
Authors: Matsuzaki Takashi , Sakaizumi Mitsuru , Shima Akihiro
Published: June 2005

We attempted to produce monoclonal antibodies against strain‐specific antigens of the Medaka, Oryzias latipes, using eight inbred strains and several wild populations. One monoclonal antibody, named m11C1, showed reactivity to the cells of one inbred strain HB11C but not to the cells of the other inbred strain HNI. The reactivity was also found for the cells of four other inbred strains but not to that for two inbred strains. To understand the character of the antigen recognized by the m11C1, wer examined wild populations of the Medaka in regard to reactivity for the m11C1. Among fish collected from 122 localities, the m11C1 exclusively recognized the cells of the fish which were classified as the Southern Population. None of the fish from the Northern, the East Korean, and the China‐West Korean Populations reacted with the m11C1 antibody. Thus, the antigen recognized by the m11C1 was named SA1 (Southern Population‐specific Antigen 1). The SA1 antigen from liver cells appeared as a single band on Western blot with a molecular mass of 31 kDa. This antigen mainly localized in epithelia of intestinal vili and in melano‐macrophages which were frequently observed in spleen and anterior kidney. Genetic corsses suggested that SA1‐positive phenotype was dominant. Moreover, SA1 was also detected in two closely related species, O. luzonensis and O. curvinotus, but not in less‐ related five species of the genus Oryzias. Origin and propagation of the SA1 antigen were discussed based on geographic and phylogenic distribution pattern of SA1. © 1993 Wiley‐Liss, Inc.
Isosmotic modulation of cell volume and intracellular ion activities during stimulation of single exocrine cells
Authors: Foskett J. Kevin , Wong Monica M. M. , Sue‐A‐Quan Greg , Robertson Marli A.
Published: June 2005

Stimulation of salivary secretion is associated with a rise of [Ca2+]i in acinar cells. We examined the osmotic and ionic consequences of activation of Ca2+‐dependent K+ and Cl− channels, by simultaneous optical determinations of cell volume and [Ca2+]i, [Cl−]i or [Na+]i during muscarinic stimulation of single salivary acinar cells, using a differential interference contrast (DIC)‐fluorescence microscope. Carbachol caused a rapid rise of [Ca2+]i, as well as a substantial cell shrinkage. Despite variability in the level and kinetics of the subsequent sustained phase of the [Ca2+]i response, cell volume was correlated with [Ca2+]i in all cases. Elevated [Ca2+]i was both necessary and sufficient to cause these changes in cell volume. The proposition that changes in cell volume reflected changes in cell solute content was confirmed by simultaneously measuring [Cl−]i and cell volume. Simultaneous determinations of cell volume and [Na+]i indicated that the initial cell shrinkage was due entirely to K+ and Cl− efflux. Subsequent to the initial shrinkage, [Na+]i rose to high levels, primarily due to activation of Na+/H+ exchange. Thus, modulation of ion transport activities under isosmotic conditions results in substantial changes in cell solute content and cell volume. Subsequent to the early Ca2+‐induced changes in these parameters, other transporters become active, but it is unclear what signals their activation. Cell swelling by osmotic dilution of the bath resulted in compensatory cell shrinkage (RVD) which was sensitive to K+ and Cl− gradients. Nevertheless, a rise of [Ca2+]i was not necessary for RVD. Osmotic shrinkage and/or cell acidification were insufficient to activate Na+ influx. Our data suggest that the intracellular signalling pathways used by cells to activate ion transport under anisosmotic conditions may not be the same as those employed under isosmotic conditions. © 1994 Wiley‐Liss, Inc.