bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chromosome assignments of the human TNF p55 and p75 receptor genes
Authors: Brownell Elise , Ranges G. E. , Sarr T. , Fiorentino L. , Godfrey M. , Pekar S. , Hart J. , Kamarck M. , Rae P. M. M. , Ruddle F. H. , Bayney R. 
Published: June 2005

AbstractAt least two different receptor molecules have been described that are capable of binding tumor necrosis factor alpha, a cytokine that plays an important role in inflammation and antitumor activity. Comparative analyses at the nucleotide sequence level suggest that these receptors are members of a newly defined protein family that also includes human and rat nerve growth factor receptors. In this study, we determine the chromosome assignments of the human TNF alpha receptor genes, one of which may have evolved as part of a conserved Hox locus‐containing chromosome segment. © 1992 Wiley‐Liss, Inc.
Atrial natriuretic peptide clearance receptors in trout: Effects of receptor inhibition in vivo
Authors: Duff Douglas W. , Olson Kenneth R. 
Published: June 2005

AbstractInactivation of circulating atrial natriuretic peptides (ANP) by specialized clearance (C) receptors has been characterized in mammals but has not been examined in fish. In the present study arterial blood pressure, urine flow, and urine electrolytes were measured in chronically cannulated rainbow trout, Oncorhynchus mykiss, during infusion of the specific C receptor inhibitor, SC‐46542. C receptor inhibition decreased blood pressure and pulse pressure, increased heart rate and urine flow, but did not affect urinary electrolyte concentrations. These responses are consistent with those produced by exogenous ANP administration and indicate that: (1) trout possess C‐type receptors capable of ANP inactivation, and (2) ANP‐like molecules are continuously released and metabolized by trout in vivo. Phosphoramidon, an inhibitor of neutral endopeptidase, did not enhance the SC‐46542 response, indicating that C receptors predominate in ANP inactivation in these fish. © 1992 Wiley‐Liss, Inc.
Prostaglandin synthesis in vitro by ovarian follicles and extrafollicular tissue of the viviparous guppy (Poecilia reticulata) and its regulation
Authors: Venkatesh B. , Tan C. H. , Lam T. J. 
Published: June 2005

AbstractDevelopmental changes in the prostaglandin synthesising potential in vitro of follicles of the viviparous guppy during oocyte growth and gestation were investigated. Basal production of PGE and PGF was low in follicles during oocyte growth, maturation, and early gestation, increased in mid and late gestation, and declined at postparturition. A similar pattern was also observed in the production of these prostaglandins by follicles at different developmental stages in the presence of exogenous arachidonic acid. Extrafollicular (EF) ovarian tissue of the guppy synthesised large amounts of PGE and PGF spontaneously as well as from exogenous arachidonic acid. Late gestation follicles and EF tissue incorporated 14C‐arachidonic acid into PGE2α, PGF2α, 6‐keto‐PGF1α, and monohydroxyeicosatetraenoic acids. The ability of mid and late gestation stage follicles to synthesise large amounts of prostaglandins suggests that it may be related to ovulation and parturition. Extrafollicular tissue may also play a role in the induction of ovulation and parturition. Dibutyryl cAMP inhibited prostaglandin production by late gestation follicles and EF tissue in a dose‐dependent manner. Although the physiological significance of the effect of cAMP is not known, it is possible that high levels of cAMP during oocyte maturation may inhibit ovulation of mature oocytes by inhibiting prostaglandin synthesis. Cortisol (25 and 250 ng/ml) inhibited PGE and PGF production by late gestation follicles. Both the doses of cortisol tested also inhibited PGE production by EF tissue. However, only the higher dose was effective in inhibiting PGF production by EF tissue. Ovarian steroids such as estradiol‐17β, testosterone, 17α,20β‐P, and progesterone (5 and 50 ng/ml) had no effect on PGE and PGF production by late gestation follicles and EF tissue. Our earlier studies on serum steroid profile in the guppy have shown that cortisol levels decline at periparturition. It is possible that this decline may remove the block on prostaglandin synthesis, leading to increased synthesis of prostaglandins, which are presumably involved in the induction of ovulation and parturition. © 1992 Wiley‐Liss, Inc.
Changes in growth hormone and prolactin messenger ribonucleic acid levels during seawater adaptation of amago salmon (Oncorhynchus rhodurus)
Authors: Yada Takashi , Kobayashi Tooru , Urano Akihisa , Hirano Tetsuya 
Published: June 2005

AbstractTo examine the changes in secretion of growth hormone (GH) and prolactin (PRL) with reference to their osmoregulatory roles, changes in pituitary mRNA levels and plasma concentrations of these hormones were examined during seawater adaptation in silvery juveniles (smolts) and precociously mature males (dark parr) of amago salmon (Oncorhynchus rhodurus). Transfer to seawater increased plasma sodium levels in both smolts and dark parr. Smolts adjusted their plasma sodium to the level associated with seawater‐adaptation (165 mEq/liter) within 3 days, whereas no adjustment was seen in dark parr; the latter failed to survive in seawater for more than 3 days. In smolts, plasma GH levels increased significantly 1 day after transfer, whereas there was no significant change in dark parr. An increase in GH mRNA levels was observed in smolts in association with increased plasma GH, whereas there was no change in dark parr. In contrast, a reduction in plasma PRL levels was consistently observed in both smolts and dark parr after transfer to seawater. However, there was no significant change in PRL mRNA levels in either smolts or dark parr. These results suggest that both gene expression and release of GH are activated by seawater transfer only in smolts with adequate seawater adaptability, whereas PRL gene expression is decreased after sea‐water adaptability. © 1992 Wiley‐Liss, Inc.
The role of the adrenal glands in regulating onset of winter fur growth in mink (Mustela vison)
Authors: Rose Jack , Sterner Mauritz 
Published: June 2005

AbstractABSTRACT The role of the adrenal glands in regulating onset of winter fur growth in mink was investigated in long‐term adrenalectomized animals. Bilateral adrenalectomy of adult female standard dark mink between June 23 and July 11, 1990, initiated onset of winter fur growth approximately 6 weeks earlier than controls. One month following completion of the winter fur growth in adrenalectomized mink, molting and growth of a new coat was observed. The type of pelage that grew as a result of the second growth wave was less dense than the normal summer or winter fur. However, this renewed hair growth suggests that adrenal hormones not only inhibit the onset of winter fur growth but also influence the duration of inactivity following each period of hair growth. Administration of deoxycorticosterone as a mineralocorticoid supplement had no effect on initiation of fur growth. It would appear that adrenal hormones are part of the mechanism through which photoperiod regulates fur growth in the mink. The identity of the adrenal hormones and their site of action is unknown. © 1992 Wiley‐Liss, Inc.
Cytoskeletal sheets appear as universal components of mammalian eggs
Authors: Gallicano G. Ian , McGaughey Robert W. , Capco David G. 
Published: June 2005

AbstractThe eggs of two mammalian species have been shown to contain novel cytoskeletal elements, referred to as cytoskeletal sheets, which undergo stage‐specific changes in spatial organization at three key developmental transitions, fertilization, compaction, and blastocyst formation. If cytoskeletal sheets have an integral role in these developmental transitions, the sheets should be present in the eggs of other mammals as well. We examined the eggs of four additional species to determine if sheets were present. Our results indicate that sheets were present and they can be categorized into two classes based on their surface appearance. Cytoskeletal sheets in eggs of hamsters and rats have a smooth surface appearance, while eggs from humans, cows, pigs, and mice have a fibrous surface appearance. In addition, we observed that species‐specific variations exist in the width of the sheets and in the density of the sheets (i.e., number per μm2) in the eggs. These species‐specific variations may relate to the role of the sheets during early development. © 1992 Wiley‐Liss, Inc.
Photo‐regulation of the hatching process of halibut (Hippoglossus hippoglossus) eggs
Authors: Helvik Jon V. , Walther Bernt T. 
Published: June 2005

AbstractHatching occurs in all vertebrates, yet knowledge about the control of this developmental transition is incomplete. Incubation of halibut Hippoglossus hippoglossus eggs in light results in sustained inhibition of hatching. The inhibitory efficacy of light is affected both by its intensity and its colour. Transfer of hatching‐arrested eggs to darkness (0.1 lux and below) reverses such inhibition and causes hatching of all eggs between 80–140 min later. Darkness is only required during the first 60 min of this induced hatching and initiates a signal which makes hatching irreversible and darkness independent. The darkness‐generated signal ultimately causes release of hatching enzyme, which digests the zona radiata so that the eggshell may be mechanically opened by the larva. We conclude that light serves as a natural cue for hatching in halibut eggs, and that halibut larvae in nature hatch in darkness. © 1992 Wiley‐Liss, Inc.
Xenopus laevis sperm proteins, previously identified as surface proteins with egg coat binding capability, are indeed histone H4, histone H3, and sperm specific protein SP2
Authors: Bernardini Giovanni , Donne Isabella Dalle , Norreri Sabrina , Negri Armando , Milzani Aldo 
Published: June 2005

AbstractRecently, four Xenopus sperm proteins thought to be involved in binding to the egg envelope were identified (Lindsay and Hedrick, J. Exp. Zool., 245:286–293, '88). We have studied the three more abundant ones of apparent molecular weight of 14, 19, and 25 kd in SDS‐PAGE. We have shown that these proteins are indeed nuclear basic proteins: the 14 kd is the histone H4, the 19 kd is the histone H3, and the 25 kd is the sperm‐specific protein SP2. © 1992 Wiley‐Liss, Inc.
A quantitative autoradiographic study of 125I atrial natriuretic factor in the heart of a teleost fish (Conger conger)
Authors: Cerra M. C. , Canonaco M. , Tota B. 
Published: June 2005

AbstractQuantitative receptor autoradiographic study of 125I‐atrial natriuretic peptide factor (ANF) in the heart of a teleost fish Conger conger has shown that a heterogenous distribution of 125I‐ANF binding exists in the different cardiac regions. Elevated ANF binding densities (3,790 fmol/mg protein) were encountered in the innermost layer (tunica intima) of the bulbus arteriosus while lower binding levels (293–403 fmol/mg protein) were revealed in atrium and ventricle. In order to determine 125I‐ANF binding characteristics (KD, Bmax) in the above cardiac sites, saturation binding assays were carried out. The results show that low 125I‐ANF KD values (28.8–52.6 pM) were found in the atrium and in the bulbus arteriosus with respect to the higher KD values (373 pM) of the ventricle. The number of binding sites were respectively 632 and 1,279 fmol/mg protein for the atrium and the ventricle, while a substantially elevated Bmax of 7,235 fmol/mg protein was found for the bulbus arteriosus. These results may furnish some insights concerning ANF receptor binding activity and its putative regulatory role of different cardiac functions. © 1992 Wiley‐Liss, Inc.
Identification of insulin‐like growth factor‐binding proteins in the circulation of four teleost fish species
Authors: Kelley Kevin M. , Siharath Kimmakone , Bern Howard A. 
Published: June 2005

AbstractInsulin‐like growth factor‐binding proteins (IGF‐BPs) were demonstrated in the circulation of four teleost fish species. In the coho salmon (Oncorhynchus kisutch), serum binding of 125I‐labelled human IGF‐I (125I‐hIGF‐I) was competitively inhibited by addition of excess recombinant bovine IGF‐I (rbIGF‐I) in a manner similar to that when rat serum was used. Western‐ligand blot procedure using the same labelled hormone identified at least three major forms of IGF‐BPs in the plasma of all four teleost species investigated: coho salmon, striped bass (Morone saxatilis), tilapia (Oreochromis mossambicus), and longjawed mudsucker (Gillichthys mirabilis). The first form is around 40–50 kDa, may be regulated by growth hormone (GH), and seems to be a good candidate for the fish version of mammalian IGF‐BP3 (which is in the same size range and is GH‐regulated). The second and third forms are 29 kDa and 31 kDa and are good candidates for the fish versions of mammalian IGF‐BP1 and IGF‐BP2, respectively, as they appear to be regulated by insulin and are in the same size range as their mammalian counterparts. Functionally different classes of circulating IGF‐BPs may be conserved between fish and mammal. © 1992 Wiley‐Liss, Inc.
Comparison of Cl−‐absorption in the intestine of the seawater‐ and freshwater‐adapted eel, Anguilla anguilla: Evidence for the presence of an Na‐K‐Cl cotransport system on the luminal membrane of the enterocyte
Authors: Trischitta F. , Denaro M. G. , Faggio C. , Schettino T. 
Published: June 2005

AbstractThe mechanism(s) of absorption of chloride ions (Cl‐absorption), as measured by the short‐circuit current (Isc, μA·cm−2), was investigated in the intestinal middle part of the seawater‐(SW) and the freshwater‐(FW) adapted eel. Tissues, mounted in an Ussing chamber and continuously perfused by gravity flow on both sides with 20 mM HCO3− ‐ 1% CO2 Ringer's solution at pH 8.0, developed a serosa‐negative transepithelial voltage (Vt, mV) and an Isc that were both lower in FW‐adapted than in SW‐adapted eels.Bilateral removal of Na+ or Cl− from the bathing solutions reduced both electrical variables to zero. Removal of K+ from or addition of Ba2+ (1 mM) to the luminal bath markedly decreased Isc and Vt. When a K+‐free plus Ba2+‐containing solution perfused the lumen, Isc and Vt were almost completely abolished. Luminal bumetanide (10−5 M), an inhibitor of Na+‐K+‐2Cl− cotransport, reduced Isc and Vt by about 90% in a few minutes.Amiloride (10−3 M) and DIDS (4,4′‐diisothiocyanostilbene‐2,2‐disulphonic acid; 10−4 M), inhibitors of Na+/H+ and Cl−/HCO3− exchangers, and hydrochlorothiazide (10−4 M), an inhibitor of the Na‐Cl symport, had no effect on Isc and Vt when added luminally. Serosal ouabain (10−3 M) abolished Isc and Vt in about 30 min. All the above experimental manoeuvres led to similar results in both SW‐adapted and FW‐adapted eels.The data suggest that in the intestine of both SW and FW eels, Cl−‐absorption is mediated by a luminally located neutral Na+‐K+‐2Cl− cotransport system. The basolaterally located Na+, K+‐ATPase, by generating an inwardly directed electrochemical gradient for Na+, provides the driving force for the active accumulation of Cl− by the electroneutral cotransporter. The K+ accumulated is refluxed by a Ba2+‐inhibitable luminal K+ conductance. © 1992 Wiley‐Liss, Inc.
Comparative kinetics of meiosis in hybrid crosses of Pacific oyster Crassostrea gigas and Suminoe oyster C. rivularis with the American oyster C. virginica
Authors: Scarpa John , Allen Standish K. 
Published: June 2005

AbstractInterspecific hybridization of bivalve molluscs within the genera Crassostrea and Pinctada have yielded progeny of one parental type, leading to speculation of gynogenetic or androgenetic development. Therefore, meiotic and early mitotic events of oocytes from the oysters Crassostrea gigas and C. rivularis fertilized with C. virginica sperm, as well as the reciprocal and control crosses, were critically observed in samples taken up to 90 minutes post‐insemination. Chromosomal material in oocytes was visualized with the DNA‐specific fluorochrome DAPI and epifluorescence microscopy. All crosses produced fertilized oocytes which were observed to proceed through meiosis and early mitosis. Fertilization was ∼20% less successful in hybrid than straight crosses of C. gigas and C. virginica (P = 0.022) but no difference in fertilization was evident in C. rivularis and C. virginica crosses (P = 0.169). The time interval between meiotic and mitotic landmarks was not significantly different among all crosses within each full reciprocal cross. There was no cytological evidence of parthenogenetic, gynogenetic, or androgenetic development. In previous reports, non‐hybrid progeny found in hybrid groups were probably contaminants. © 1992 Wiley‐Liss, Inc.
Sexually differentiated mechanisms of sterility in interspecific hybrids between Oryzias latipes and O. curvinotus
Authors: Hamaguchi Satoshi , Sakaizumi Mitsuru 
Published: June 2005

AbstractFertility of interspecific hybrids between Oryzias latipes and O. curvinotus was examined. F1 females were able to lay eggs but males were sterile. Histological examination of the ovaries of hybrids revealed that oogenesis does not proceed normally in spite of the apparent fertility. Most oocytes degenerated at the pachytene stage of the meiotic prophase, and only a few entered the diplotene stage to develop into ova. Hybrid males could induce females to spawn eggs, an indication that they had differentiated completely into true males. However, they did not produce fertile sperm. Most germ cells in testes of hybrids passed through almost the entire process of spermatogenesis, but deviations from the normal course of events were observed during spermiogenesis. The condensation of chromatin in spermatids occurred, but the diameters of sperm heads were about 1.5‐fold larger than those of normal ones. Prominent abnormalities were apparent in the quantity and arrangement of microtubules in the cytoplasm. Abnormal spermatozoa were phagocytized by Sertoli cells. These observations indicate that the mechanisms of impaired gametogenesis in these interspecific hybrids are sexually differentiated. © 1992 Wiley‐Liss, Inc.
Osmotic and ionic regulation during hypoxia in the medicinal leech, Hirudo medicinalis L.
Authors: Hildebrandt Jan‐Peter , Zerbst‐Boroffka Irene 
Published: June 2005

AbstractThe concentrations of inorganic and organic ions and osmolality in the blood of the medicinal leech, Hirudo medicinalis, were determined during normoxia and hypercapnic and hypocapnic hypoxia. In normoxic animals, the blood sodium concentration was 124.5 ± 4.2 mmol/l and the total cation concentration was 132.2 ± 4.3 mEq/l (mean ± S.D.). Major anionic compounds were chloride (40.8 ± 1.6 mmol/l), bicarbonate (8.4 ± 1.3 mmol/l), and organic anions (42.5 ± 2.3 mEq/l). Among the latter, malate accounts for 30.4 ± 2.2 mEq/l. The nature of the remaining anion fraction, which balances cation and anion concentrations in leech blood, remains unknown.Within 96 h of hypercapnic hypoxia, the amount of organic osmolytes in leech tissue increased from the control level of 56.6 ± 9.1 to 158.3 ± 19.5 μmol/g dry weight. An even higher amount of organic acids was accumulated within 96 h of hypocapnic hypoxia (218.0 ± 53.7 μmol/g dry weight). A possible reason for this is that lactate, which is a major end‐product of hypocapnic hypoxia, cannot be excreted to the external medium as easily as propionate.The accumulation of blood organic acids generating osmotic stress in the animals was compensated by an equimolar decrease in sodium and chloride ion concentrations. In hypercapnic animals these changes resulted in a constant osmotic concentration of the blood (200 mosmol/kg H2O) during the experimental period. Between 24 and 96 h of hypocapnic hypoxia, however, the increase in the osmotic gradient between animal and medium was correlated with further net water uptake and the obvious deterioration of the volume‐ and ion‐regulatory mechanisms in these animals. © 1992 Wiley‐Liss, Inc.
Epibolic extension of the presumptive ectodermal layer of embryos of the newt Cynops pyrrhogaster before and during gastrulation
Authors: Komazaki Shinji 
Published: June 2005

AbstractEpibolic extension of the presumptive ectodermal layer (PEL) was investigated in embryos of the newt Cynops pyrrhogaster before and during gastrulation. The PEL was composed of only one layer of columnar cells at all stages examined. The cells of the PEL became elongated from the blastula to the early gastrula stage. They were most elongated at the early gastrula stage and then shortened during gastrulation. Present observations suggest that changes in cell shape of the PEL play an important role in the control of the epibolic extension of the newt embryos.The morphology and movement of the isolated cells from the PEL were examined in an attempt to elucidate the role of cell movement in epibolic extension of the PEL. Blebbing and vermiform cells which showed active cell movement appeared at the early blastula stage. The blebbing cells, which formed large hyaline blebs that moved around the circumference of each cell, appeared in large numbers at the early blastula stage. The frequency of the blebbing cells decreased from the early blastula to the early gastrula stage and increased again during gastrulation. The vermiform cells, which had an elongated cell body and moved in a worm‐like manner, increased in frequency from the early blastula to the early gastrula stage. The relative number of such vermiform cells was maximal at the early gastrula stage and decreased abruptly during gastrulation. These results suggest that the elongation of the cells of the PEL is controlled by the active cell movement which resembles that of a worm. © 1992 Wiley‐Liss, Inc.
Body temperature rhythm of the tree shrew, Tupaia belangeri
Authors: Refinetti Roberto , Menaker Michael 
Published: June 2005

AbstractThe circadian rhythm of body temperature of the tree shrew Tupaia belangeri was studied by telemetry. The amplitude of the daily (or circadian) variation was found to be much larger than that of most endotherms (amplitude ∼ 5°C) and the bimodal shape of the rhythm differed from the cosine waveform that characterizes the temperature rhythms of most other species. In free‐running conditions, as well as in the entrained state, the temperature rhythm remained synchronized to the rhythm of locomotor activity. © 1992 Wiley‐Liss, Inc.
Cleavage inhibition by cell shape change
Authors: Rappaport R. 
Published: June 2005

AbstractThe division mechanism of animal cells is positioned by the mitotic apparatus. The mitotic apparatus determines the position by a pattern of regional inequality of its effect on the surface and cortex. Because the effect of the asters decreases with distance, the location of the division plane can be manipulated geometrically. It follows that cytokinesis should be preventable by imposition of a cell shape that prevents the normal pattern of unequal aster effect. The shape that inhibits division reveals something of the normal pattern of aster effect as well as the nature of the immediate response of the surface to the aster.In 13 of 13 experiments, sand dollar (Echinarachnius parma) eggs fail to cleave when the polar and subpolar regions are extruded in the mitotic axis, although some surface contraction may develop in the extruded region. Extrusion was accomplished by sucking the appropriate regions into opposed pipets. A computer model of the relative aster effect in this circumstance indicates that the minimum is at the equator, and the maximum is in the extruded regions. These experiments indicate that furrows do not form where the aster effect is minimal. Previous experiments showed that cells divide when cells are artificially constricted in the equatorial plane where the aster effect is maximal. Together, the geometrical experiments strongly suggest that furrowing activity occurs in maximally affected areas. These results are consistent with the equatorial contraction theory of cell division, but inconsistent with the aster relaxation theory. © 1992 Wiley‐Liss, Inc.