bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evolution of immunity: Potential immunocompetence of the echinoid axial organ
Authors: Larson Maureen K. , Bayne Christopher J. 
Published: June 2005

AbstractAntigen‐specific recognition is a hallmark of vertebrate lymphoid immune responses. Although isolated studies have suggested specific responses in some invertebrate phyla, those claims remain to be independently verified. Echinoderms share the deuterostome lineage with vertebrates and thus represent an important group for examinations into the origins of vertebrate immune competence. Investigations in asteroids suggested axial organ involvement in an antigen‐specific immune response. To independently test this organ's role in echinoid immunity, Strongylocentrotus purpuratus axial organ cells from injected animals were monitored for the production of membrane‐bound and secreted molecules specific for the injected hapten (TNP). Cells of the axial organs were assayed for specific membrane receptors in an immunocytoadherence assay. Urchin axial organ cells did not bind TNP‐sheep red blood cells and, while hemagglutination was observed, it was neither TNP‐inhibitable, nor dependent on previous exposure to TNP. Secretion of antigen‐specific molecules was evaluated by enzyme‐linked immunosorbent assay. Coelomic fluids from several urchins contained molecules that bound TNP, but the presence of such molecules was not dependent on prior treatment. Titrational analysis revealed identical binding curves against the hapten, TNP, the carrier, LPS, or an unrelated protein, BSA, implying nonspecificity of binding. Assays were validated using rainbow trout immune responses to TNP. The data presented do not support the hypothesis that echinoid axial organ cells respond to antigenic challenge in a specific, inducible manner. The results do support the idea that the multigene complex necessary for the formation of antibodies evolved after echinoderm and chordate ancestors diverged. © Wiley‐Liss, Inc.
Female reproductive profile in a fertile, genetically obese line of rats
Authors: Hisano Noriyuki , D'Ottavio Alberto Enrique , Calderari Susana Agnese 
Published: June 2005

AbstractThe female reproductive profile of a fertile genetically obese line of rats, named β, is characterized. Hypophysis, ovaries, oviducts, and uteri weights do not differ from those of nonobese controls. Histological features in ovary, uterus, and vagina in β line and α controls are similar, in agreement with classical descriptions in the subject.Vaginal opening, number of estrus, number of corpora lutea at ovulation time, and pregnancy patterns (i.e., ovary weight, number of corpora lutea, sites of implantation, and living fetuses, as well as productivity, fertility, litter size, and preweaning mortality) show no significant differences between obese and nonobese animals.From a reproductive standpoint, obese β line would behave as nonobese. Up to now β would represent the only fertile genetically obese line of rats, appearing as a profitable biological model to widen and deepen reproductive analysis on obesity. © Wiley‐Liss, Inc.
Ontogeny of cardiac function in the brine shrimp Artemia franciscana Kellogg 1906 (Branchiopoda: Anostraca)
Authors: Spicer John I. 
Published: June 2005

AbstractIn newly hatched brine shrimp (Artemia franciscana) cardiac organogenesis and function could only take place with the onset of segmentation. Consequently differences in age, body size and temperature (in the range 22–34°C) affected the ontogeny of cardiac activity only indirectly, through their influence on developmental stage. Once present the frequency of cardiac activity (heart beat) increased with increasing body size and concomitant differentiation of cardiac tissue. At least initially, (dry body weight 11–16 μg) heart rate was independent of temperature and weight specific heart rate was independent of body size. When differentiation neared completion, and cardiac growth switched to elongation (dry body weight > 16 μg) there was a change in the pattern of cardiac function. There was now a decrease in heart beat with increasing body size and weight specific heart rate showed an inverse relationship with body weight. Heart rate also became temperature dependent, although it remained relatively insensitive. In conclusion it is suggested that the ontogeny of cardiac function in Artemia is constrained by an anamorphic (direct) pattern of development where segment formation occurs post hatch. Early cardiac functioning cannot be predicted on an allometric basis, as cardiovascular structure and function changes qualitatively during ontogeny. © Wiley‐Liss, Inc.
Existence of adrenodoxin‐like peptide in teleost fishes: Immunohistochemical evidence
Authors: Sampath‐Kumar R. 
Published: June 2005

AbstractThis communication reports the first evidence, based on immunohistochemistry, for the presence of adrenodoxin‐like protein in poikilothermic vertebrates, two species of teleost fishes. Adrenodoxin (adrenal ferredoxin) is an iron‐sulphur protein present in the mitochondrial matrix of mammalian and avian adrenal cortex. Presence of this protein in the adrenal cortex or its equivalent (interrenal) of poikilothermic vertebrates is unknown to date. Contrary to the expectation, an earlier study using EPR spectrometry failed to demonstrate adrenodoxin in tiger shark and green turtle leading to the hypothesis that mitochondrial steroid hydroxylase systems (Type II enzymes) in poikilotherms might be similar to the microsomal counterparts (Type I enzymes) which does not involve adrenodoxin. ABC method of immunohistochemistry in the present study demonstrated that antiserum to bovine adrenodoxin reacts specifically and intensely with interrenal cells of the Asian seabass (Lates calcarifer) and the tilapia (Oreochromis mossambicus), indicating that adrenodoxin or its homologue is present in the poikilotherms also. The results further suggest the existence of a distinct electron transport system for mitochondrial steroid hydroxylation in poikilotherms as in mammals. © Wiley‐Liss, Inc.
Thread biomechanics in the two orb‐weaving spiders Araneus diadematus (Araneae, Araneidae) and Uloborus walckenaerius (Araneae, Uloboridae)
Authors: Köhler Tamara , Vollrath Fritz 
Published: June 2005

AbstractThe absorption of high kinetic energy by a small amount of material depends not only on the quality of the material but also on the structural design of the elements involved. Using a rapid response microbalance, we measured the tensions of radial threads in webs of the garden cross spider, Araneus diadematus. We also measured the stress‐strain characteristics of dry radius and wet spiral threads laid down by A. diadematus, as well as of the very different and dry spiral threads laid down by the hackled‐band weaver, Uloborus walckenaerius.The radius threads of A. diadematus showed good extensibility (e = 39. 4%), high tensile strength (s = 1153. 8 MPa) and large hysteresis (56%) which indicates that they can function as shock absorbers and structural elements. Although fewer radii were built in the upper than in the lower half of the Araneus web, our method found no systematic difference between the average pretensions of individual radius threads in these two halves. However, pretension in the upper half of the web showed greater variation.Orb weavers employ two different mechanisms to increase the energy‐absorbing capacity of their respective capture spirals. The sticky spiral of Araneus diadematus absorbed energy by large extensibility (about 475%) of the wetted thread which developed substantial force only after 100–200% extension, and the entire thread failed suddenly. The hackled band of Uloborus walckenaerius had shorter extensibility (about 125%) and it absorbed energy by friction of the fine hackled fibres, many of which needed to break in succession before a thread failed. © 1995 Wiley‐Liss, Inc.
Characterization of plasma membrane Na+/H+ exchange in eel (Anguilla anguilla) intestinal epithelial cells
Authors: Vilella S. , Zonno V. , Lapadula M. , Verri T. , Storelli C. 
Published: June 2005

AbstractThe ability of eel intestinal epithelial cells to recover from an acute acid load was analysed using the fluorescent dye 2′, 7′‐bis‐carboxy‐ethyl‐5, 6‐carboxyfluorescein (BCECF) and cell suspensions. Under these experimental conditions (bicarbonate‐free solutions) the resting pHi in cells prepared from sea‐water (7.52 ± 0.031) and fresh‐water (7.50 ± 0.094) adapted animals proved to be similar. The recovery rate (following an acid load) increases by increasing the Na ion concentration in the extracellular medium. This pHi recovery is competitively inhibited by the specific inhibitor dimethylamiloride (DMA) with a low Ki in sea‐ (1.2 μM) as well as in fresh‐water (1.3 μM) adapted animals, indicating the presence of a specific Na/H exchange activity in these cells. Using basolateral membrane vesicles it could be demonstrated that this activity is located on the basolateral side of the enterocyte membrane. The kinetic parameters (Kapp and Jmax) of this exchanger are similar in fresh‐water and sea‐water adapted animals suggesting that no salinity adaptation occurs, thus excluding the involvement of the antiporter in the osmoregulatory processes. These results are in agreement with the presence in the plasma membrane of the eel enterocytes of a Na/H‐l (housekeeper) form of the antiporter. © 1995 Wiley‐Liss, Inc.
Model for cooperative control of positional information in Drosophila by bicoid and maternal hunchback
Authors: Reinitz John , Mjolsness Eric , Sharp David H. 
Published: June 2005

AbstractThe blastoderm of the fruit fly Drosophila melanogaster is unusually well suited for analysis of fundamental questions in animal development. One such question is how genes specify the positional information which determines the developmental pathways (fate) of cells at appropriate spatial locations. In this paper we propose a dynamical model of gene regulation which explicitly describes how positional information is used in the blastoderm. The model is applied to analyze important experimental findings on the dependence of cell fate on the concentration of the Bicoid morphogen. The model shows that positional information in the presumptive middle body is cooperatively determined by maternal products of the bicoid and hunchback genes. © 1995 Wiley‐Liss, Inc.
Activation of murine oocytes with Ca2+ ionophore and cycloheximide
Authors: Hagemann L. J. , Hillery‐Weinhold F. L. , Rutledge M. L. Leibfried , First N. L. 
Published: June 2005

AbstractA Ca2+ ionophore (A23187, 3 μM) and inhibitor of protein synthesis (cycloheximide, 10 μg/ml) were used sequentially as a unique method for activating mouse oocytes in vitro. Brief exposure of oocytes to A23187 followed by 6 hr in cycloheximide resulted in a higher activation rate (93.8%) compared to A23187 or cycloheximide alone (37.7% and 36.5%, respectively) or the two reagents in reverse order (29.8%). The parthenogenones consistently contained a single pronucleus and second polar body, and showed a high degree of developmental potential, as assessed by transfer to recipient females or addition of a male pronucleus followed by transfer to recipients. This method is a useful way of obtaining large numbers of activated haploid mammalian oocytes for further developmental studies. © 1995 Wiley‐Liss, Inc.
Immunohistochemical evidence that gonads and gonad‐associated tissues are sites for enrichment with immunoglobulin‐containing cells in adult chickens
Authors: Zettergren Leslie D. 
Published: June 2005

AbstractImmunohistochemical staining of tissue sections prepared from gonads and gonad‐associated tissues obtained from adult chickens was performed in order to assess the possibility that these tissues may be sites of enrichment with IgM‐containing cells in various B lineages. Evidence is presented which suggests that IgM‐containing B lineage cells are present in 1) the ovarian stroma and subcapsular areas of the ovary and 2) the interstitium and subcapsular areas of the epididymis of the testes. These represent new sites reported for B lineage cells in adult chickens. Some questions relevant to the physiologic, ontogenetic, and phylogenetic implications of these observations relative to vertebrate hematolymphopoietic processes are included. © 1995 Wiley‐Liss, Inc.
Interdependence of corticosterone and thyroid hormones in larval toads (Bufo boreas). I. Thyroid hormone‐dependent and independent effects of corticosterone on growth and development
Authors: Hayes Tyrone B. 
Published: June 2005

AbstractIn a previous study (Hayes et al. [1993] J. Exp. Zool., 266: 206–215), we demonstrated that exogenous corticosterone (B) inhibited growth, and had varied effects on development and metamorphosis in the toad(Bufo boreas). The current study determined the relation between the action (length and height), rear leg growth and differentiation, and foreleg emergence (FLE). Thiourea (Thio; a goitrogen) and metyrapone (MTP; a glucocorticoid synthesis inhibitor) were used to determine the role of endogenous hormones in growth and development. These inhibitors were also used in various combinations with the thyroid hormones, thyroxine (T4) and triiodothyronine (T3), to determine the extent to which B's actions depend on the thyroid hormones. B was ineffective at inducing tail reduction (length and height) in the presence of Thio, but B enhanced the effects of both thyroid hormones, suggesting that the action of B on the tail were dependent on thyroid hormones. B inhibited body growth even in the presence of Thio, but did not enhance thyroid hormone's inhibition of growth. B alone stimulated foreleg emergence (FLE) and enhanced thyroid hormone's activity on FLE when B and the thyroid hormones were given in combination, but did not induce FLE in the presence of Thio. B stimulated rear leg development, but not in the presence of Thio, suggesting that this effect was due to interactions with thyroid hormones. Furthermore, MTP antagonized the stimulatory effect of T4 on rear leg development, suggesting that endogenous B also interacted with exogenous thyroid hormones. While the thyroid hormones stimulated rear leg growth, B inhibited rear leg growth and antagonized the effects of the thyroid hormones when the hormones were given together. This study demonstrated that while some of the effects of B (such as the stimulation of tail resorption) depend on endogenous thyroid hormones, other effects (such as the inhibition of rear leg growth) are antagonistic to the thyroid hormones. © 1995 Wiley‐Liss, Inc.
Interdependence of corticosterone and thyroid hormones in toad larvae (Bufo boreas). II. Regulation of corticosterone and thyroid hormones
Authors: Hayes Tyrone B. , Wu Tzu Hao 
Published: June 2005

AbstractTypically, the role of corticosterone (B) in metamorphosis is considered secondary to that of thyroid hormone, with B having only enhancing effects. In the current study, we demonstrate that the relationship between the thyroid hormones and B is much more complex and that thyroxine (T4) may depend on B for some of its functions. Tadpoles of the western toad (Bufo boreas) were treated with various combinations of corticosterone (B), thyroxine (T4), triiodothyronine (T3), a goitrogen (thiourea; Thio), and a corticoid synthesis inhibitor (metyrapone; MTP). Hormones were extracted from individual tadpoles and whole‐body hormone levels determined by radioimmunoassay. B‐treatment decreased the ratio of T4 to T3, suggesting that B increased the conversion of endogenous T4 to T3. In addition, B‐treatment in combination with T4 resulted in high whole body‐levels of T3. B also caused a decrease in whole body‐thyroid hormone levels (T4 and T3), suggesting negative feedback on the hypothalamo‐pituitary‐thyroid axis and T3 had a similar effect, decreasing whole body‐T4 levels. T4‐treatment, but not T3, increased whole body‐B levels and MTP‐treatment in combination with T4 prevented the stimulatory effect of T4 on B production. MTP‐treatment alone blocked all steroid metabolism of [3H]progesterone by the interrenal in vitro, and lowered whole body‐B levels three‐fold in vivo. Thio‐treatment reduced thyroid hormone levels and also resulted in decreased B. Finally, we suggest that these results demonstrate a system in which T4 may regulate its own potency: increasing T4 stimulates B production, which increases the conversion of T4 to its more active form T3. Rising T3 levels then cause a decrease in T4, removing the stimulatory effect of T4 on B. These interactions between the thyroid hormones and B help clarify the mechanisms underlying the morphological effects of these hormones described in the previous study. © 1995 Wiley‐Liss, Inc.
Role of steroids in antler growth of red deer stags
Authors: Suttie J. M. , Fennessy P. F. , Lapwood K. R. , Corson I. D. 
Published: June 2005

AbstractA series of six studies were carried out in red deer stages to test hypotheses concerning the importance of steroid control of velvet antler growth and to investigate mechanisms by which these hormones exert their effects. Medroxyprogesterone acetate (MPA) an LH inhibitor administered to stags during hard antler caused premature antler casting, reduced subsequent antler weight and caused a reduction in the LH and testosterone responses to GnRH. In two separate studies blockade of testosterone receptors with cyproterone acetate (CPA) administered to stags, either during early velvet antler growth or during the hard antler stage, significantly reduced LH and testosterone responses to GnRH. In both studies antler length, but not weight, was increased by CPA treatment. In another study testosterone implants were used to pervent the gradual decline in plasma testosterone levels normally observed during winter. Implants were removed 3 weeks before the anticipated date of antler casting. The implants significantly increased plasma testosterone levels and subsequent antler growth (expresses as a proportional increase compared with the previous year) compared with untreated controls. To determine whether the annual cycle of plasma testosterone response following GnRH stimulation was due simply to a lack of LH stimulation, ovine LH was injected on six occasions at defined stages of the antler cycle to red deer stags and the testosterone response measured. The testosterone responses were low at antler casting and during velvet antler growth compared with antler cleaning and peak rut. It appears low level of testosterone levels are due, in part, to a loss of responsiveness by the testes to LH as well as a low level of secretion of LH during the antler growing season. Finally synthetic ACTH was injected at the same defined stages of antler growth as in the previous study to determine whether cortisol and adrenal androgen production altered with the stage of the antler cycle. No significant differences were found in the dehydroepiandrosterone (DHEA) response, but cortisol responses were higher from late velvet antler growth to peak rut, compared with the times of antler casting and early velvet growth. Overall it was concluded that velvet antler growth can occur without testosterone stimulation during the period of velvet growth, but the data reinforce the concept that the timing of antler growth is linked to the annual cycle of testosterone. © 1995 Wiley‐Liss, Inc.
Lysophosphatidylcholine treatment allows interspecies fertilization of hamster oocytes with zona pellucida by human spermatozoa
Authors: Riffo Marta , Parraga Mario 
Published: June 2005

AbstractThe study of interspecific gamete interactions has been improved by the use of in vitro fertilization techniques. Zona pellucida is at the cellular level the main barrier to cross‐fertilization. Moreover, there are several cases in which the heterologous spermatozoa fail to enter the cytoplasm of zona‐free oocytes, emphasizing the notion that another important barrier exists to cross‐fertilization at the egg plasma membrane level. We report here a simple method to fertilize hamster oocytes with zona pellucida by human spermatozoa. We used lysophosphatidylcholine (LPC), a fusogenic agent, to treat spermatozoa, spermatozoa and zona‐intact oocytes, or zona‐intact oocytes alone. This molecule allows the penetration of hamster oocytes zona by human spermatozoa. Our results suggest that LPC modifies the zona pellucida of oocytes and the plasma membrane of both gametes in vitro, favouring sperm penetration through the zona pellucida and gamete fusion. © 1995 Wiley‐Liss, Inc.
Effects of acclimation salinity and in vitro medium osmotic pressure on the incorporation of3H‐leucine into the two prolactins of the tilapia, Oreochromis mossambicus
Authors: Yoshikawa‐Ebesu Joanne S. M. , Borski Russell J. , Richman N. Harold , Grau E. Gordon 
Published: June 2005

AbstractThe control of synthesis of the two prolactins (tPRL188 and tPRL177) in the anterior‐most portion of the pituitary, the rostral pars distalis (RPD), was investigated in freshwater (FW)‐ and seawater (SW)‐ acclimated tilapia. Individual RPD of FW and SW male tilapia were incubated in either hyposmotic or hyperosmotic medium containing3H‐leucine for various intervals, up to 360 min. The total quantity of the two tPRLs in media and RPD was assessed by gel electrophoresis and scanning densitometry of the stained bands. Synthesis was characterized as the uptake of3H‐leucine into the tPRL molecules. Results showed greater synthesis and release of both3H‐tPRLs in the RPD from FW tilapia than in those from SW‐ acclimated tilapia. The in vitro synthesis of both prolactins tPRLl88 and tPRL177 in RPD of FW tilapia and tPRLl77 in RPD of SW fish was also augmented by exposure to hyposmotic medium. The ratio of the appearance of newly synthesized3H‐ tPRLl88:3H‐tPRL177was approximately 1.3 in FW tilapia RPD and approximately 0.5 in SW tilapia RPD. The delay between effect of osmotic pressure on tPRL release and its effect on tPRL synthesis suggests that the rapid effect of osmotic pressure upon PRL release is at least partially independent of its effect upon tPRL synthesis. Moreover, the altered ratios of tPRL188 and tPRL177 observed in our studies suggest that the synthesis rates of the two tPRLs are differentially sensitive to environmental salinity. © 1995 Wiley‐Liss, Inc.
Incilaria mucus agglutinated human erythrocytes
Authors: Furuta Emiko , Takagi Takashi , Yamaguchi Keiichiro , Shimozawa Atsumi 
Published: June 2005

AbstractThe body surface mucus from the land slug, Incilaria fruhstorferi, not only opsonized sheep red blood cells (SRBC) and agglutinated human types A and B erythrocytes (HRBC) but also caused hemolysis of B type HRBC 12 h after agglutination. The mucus‐induced hemagglutination was specifically inhibited by a low concentration of N‐acetyl D‐galactosamine (GaINAc), and all of this activity was completely inactivated by heating at 56°C for 30 min. SDS‐polyacrylamide gel electrophoresis of water soluble fraction of the mucus showed that this fraction contained several proteins, the molecular mass of the main band being 35 KD. © 1995 Wiley‐Liss, Inc.