bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seasonal variations in hair pigmentation of white‐tailed deer and their relationship to sexual activity and plasma testosterone
Authors: Bubenik G. A. , Bubenik A. B. 
Published: June 2005

AbstractIntensity of hair pigmentation of dorsal scrotum, nose, cheek and forehead areas of seven mature, male white‐tailed deer were determined from close‐up colour slides taken once a month during a 2‐year period. Blood samples and skin biopsies from forehead areas were taken at the same time as the photographs. Plasma testosterone (T) levels were measured by radioimmunoassay and T in the skin was investigated by immunohistology. Seasonal variations of hair pigmentation are most pronounced in the forehead region followed by the cheek, scrotum, and nose area. Peak blood levels of T (15.4 ng/ml) were detected in November. The highest correlation between T levels and pigmentation of the forehead area (R = 93%; R2 = 0.87), was established when pigmentation values were shifted two months ahead. Immunohistologically detectable T was localized in hair follicles, hair sheets and apocrine glands but not in the sebaceous glands. It is hypothesized that pigmentation of head regions might serve as a visual cue indicating the sexual status of an individual.
An α2‐macroglobulinlike activity in the blood of chelicerate and mandibulate arthropods
Authors: Armstrong Peter B. , Rossner Michael T. , Quigley James P. 
Published: June 2005

AbstractThe α2‐macroglobulins are large molecular weight proteinase‐binding proteins that inhibit the ability of proteinases to hydrolyze protein substrates without suppressing activity against amide or ester substrates. They are also able to protect the active site of bound proteinases from active site inhibitors of suitably high molecular weight. The ability to protect the amidolytic activity of trypsin from the macromolecular active site inhibitor, soybean trypsin inhibitor, was used to demonstrate an α2‐macroglobulinlike activity in the blood of the horseshoe crab, Limulus polyphemus and the crustaceans Libinia emarginata (the spider crab) and Cancer borealis (the Jonah crab). The α2‐macroglobulinlike activities of L. polyphemus and L. emarginata are sensitive to methylamine, but that of C. borealis is relatively insensitive. The molecular weights (mw) of the trypsin‐protecting proteins in L. emarginata and C. borealis, estimated from gelfiltration studies, are, respectively, 480 × 103 and 460 × 103, and are significantly smaller than that of L. polyphemus (Mr = 570 × 103).
Metabolic correlates of intracellular pH change during rapid contractile activity in a molluscan muscle
Authors: Chih C. P. , Ellington W. R. 
Published: June 2005

AbstractIntracellular pH (pHi) changes during burst contractile activity in in vitro preparations of phasic adductor muscle of the bay scallop, Argopecten irradians concentricus, were monitored using phosphorus nuclear magnetic resonance (31P‐NMR) spectroscopy. A transient alkalinization (from pHi 7.06 to 7.15) was observed during the first period of contractions. The predominant mode of adenosine triphosphate (ATP) production during this period was by hydrolysis of arginine phosphate, a proton consuming process. Subsequent contractions of the muscle resulted in a gradual acidification, with pHi approaching 6.94. During these later stages of contraction, glycolytic production of octopine was a major source of ATP. The net proton yields of energy transformations were estimated, based on proton consumption by arginine phosphate utilization and proton yield of octopine production. The resulting predicted pattern of proton change was very similar to those of observed changes in pHi. Intracellular pH changes during contractile activity in A. irradians concentricus phasic adductor muscle are strongly correlated with the pattern of proton yield of metabolic energy transformations taking place in the tissue.
Changes in the rates of glycogenesis, glycogenolysis, lipogenesis, and lipolysis in selected tissues of the coho salmon (Oncorhynchus kisutch) associated with parr‐smolt transformation
Authors: Sheridan Mark A. , Woo Norman Y. S. , Bern Howard A. 
Published: June 2005

AbstractThe rates of glycogenesis, glycogenolysis, lipogenesis and lipolysis were determined in selected tissues of the coho salmon, Oncorhynchus kisutch, during the period of parr‐smolt transformation between February 1983 and June 1983. Glycogen synthesis in the liver, measured by uridine diphosphate formation, decreased 54% from initial levels. Liver glycogen phosphorylase a activity increased by 66%. Neutral lipid (sterol) and fatty acid synthesis in the liver and mesenteric fat was measured by tritium incorporation. Fatty acid synthesis in the liver and mesenteric fat decreased by 88% and 81%, respectively, between late February (parrs) and early June (smolts). There was no significant change in the rate of tritium incorporation into liver or mesenteric fat neutral lipids during the sampling period. Lipolytic rates were assessed by measuring the release of 14C‐oleic acid from 14C‐triolein in the presence of partially purified triacylglycerol lipase enzyme preparations from the liver, dark muscle and mesenteric fat. Liver, dark muscle and mesenteric fat lipase activity increased by 86%, 146% and 289%, respectively, during the sampling period. Increased glycogen and lipid breakdown, and concomitant decreased glycogen and fatty acid synthesis would contribute to the lipid and glycogen depletion observed in salmonid species undergoing parr‐smolt transformation.
Fertilization potential and polyspermy prevention in the egg of the nemertean, Cerebratulus lacteus
Authors: Kline Douglas , Jaffe Laurinda A. , Tucker Richard P. 
Published: June 2005

AbstractWe investigated the electrical properties of the egg of the nemertean worm Cerebratulus, and found evidence that an electrically‐mediated polyspermy block operates for a period of about 1 hr after fertilization. At fertilization, in natural or artificial sea water, the membrane potential shifts from its resting level of about −66 mV to a peak of about +43 mV, and in most cases remains greater than 0 mV for more than 1 hr. The average potential during the first 30 min is +22 ± 8 mV (SD, n = 12). When the external Na+ concentration is reduced from 486 to 51 mM (choline substituted) the fertilization potential amplitude is reduced; the average potential during the first 30 min is −27 ± 21 mV (SD, n = 5). Eggs inseminated in 51 mM Na+ sea water become polyspermic, indicating that polyspermy prevention depends on an electrically‐mediated mechanism. The electrical block is required for about 60 min, since transfer to 51 mM Na+ sea water during this period results in polyspermy. During the first hour following fertilization, the egg is also developing a permanent, nonelectrical block; the degree of polyspermy which results upon transfer to low Na+ sea water decreases progressively with time. The permanent block appears to be at the level of the egg plasma membrane or glycocalyx, since the egg envelope is not a barrier to sperm penetration, nor does its removal induce polyspermy. Electron micrographs show no obvious changes in the morphology of the extracellular layers, plasma membrane or cortex of the egg after fertilization.
The morphology of the migrating epiblast edge in gastrulating quail embryos: An SEM study of the effects of tissue handling before fixation on the attachment side
Authors: Andries L. , Vakaet L. 
Published: June 2005

AbstractThe expansion of the quail extraembryonic epiblast is a useful system for the study of epithelial sheet locomotion. A band of cells at the epiblast edge, referred to as edge cells (EC), adheres to the vitelline membrane. The attachment side of the EC and the dorsal surface of the submarginal cells were examined with scanning electron microscopy (SEM) after different fixation procedures. Our results indicate that especially the number of the submarginal microvilli and the surface structures of the lamellipodia are affected by tissue handling before fixation. The attachment region consists of overlapping lamellipodia that are bordered by filopodia. Proximal edge cells have a smooth contour, and they are probably elongated and oriented perpendicularly to the direction of locomotion of the EC. Parts of the proximal edge are occupied by lamellipodia and threadlike extensions. The submarginal cells located nearest the EC are usually outlined by intercellular ridges and numerous blebs, whereas the more central cells are outlined by microvilli.
Testicular cell differentiation in fetal mouse ovaries following transplantation into adult male mice
Authors: Taketo‐Hosotani Teruko , Merchant‐Larios Horacio , Thau Rosemarie B. , Koide Samuel S. 
Published: June 2005

AbstractTesticular development is a complicated process involving differentiation and arrangement of several cell types. To analyze the process of testicular organization we examined the sequence of the appearance of testicular structures induced in fetal ovaries following transplantation. Fetal mouse ovaries on the twelfth day of gestation were transplanted beneath the kidney capsules of adult male mice. They continued to develop morphologically as ovaries until the eleventh day after transplantation, when seminiferous cord formation and testosterone production began in addition to follicle development (ovotestes). Between the eleventh and fourteenth day after transplantation, ovarian grafts frequently contained transitional structures consisting of Sertoli cells, pregranulosa cells, a third type of cells which show intermediate characteristics between Sertoli and pregranulosa cells, and oocytes enclosed by common basal lamina. Leydig cells or peritubular myoid cells were not found in the transitional area, whereas these cells were present around seminiferous cords composed only of Sertoli cells. Oocytes were absent or degenerated in the well‐developed seminiferous cords. The present findings suggest that, in ovarian grafts, pregranulosa cells can differentiate into Sertoli cells, which are responsible for the organization of the seminiferous cords, degeneration of oocytes, and differentiation of other testicular somatic cell types.
Proteolysis of the zona pellucida by acrosin: The nature of the hydrolysis products
Authors: Urch Umbert A. , Wardrip Nathan J. , Hedrick Jerry L. 
Published: June 2005

AbstractBoar sperm acrosin was previously shown to hydrolyze the porcine zona pellucida in a specific and limited fashion. The action of acrosin on its presumed physiological substrate was investigated further in terms of the hydrolysis products formed. Peptide mapping experiments of zona pellucida glycoprotein families using acrosin demonstrated the formation of several products 2–4K smaller than the original susceptible families. When zona pellucida hydrolysates were examined with gel filtration, the hydrolysis products were associated in large macromolecular aggregates. These observations suggest that zona pellucida solubilization by acrosin may not be a relevant criterion for assessing acrosin's role in sperm penetration of the zona pellucida.
Demonstration of the maternal inheritance of avian mitochondrial DNA in chicken‐quail hybrids
Authors: Watanabe T. , Mizutani M. , Wakana S. , Tomita T. 
Published: June 2005

AbstractThe mtDNAs of chicken and Japanese quail can be readily distinguished from each other following electrophoresis after digestion with the restriction endonucleases, Hind III and Sal I. In hybrids between female quail and male chicken, the cleavage patterns of mtDNA were the same as the quail restriction fragment patterns. These results indicate that the avian mtDNA is maternally inherited. On the other hand, isozyme analysis revealed that the nuclear encoded enzyme GPI was assembled from both paternal and maternal gene products.
The effect of hypoosmotic stress on glycine influx in isolated muscle cells of Cancer irroratus
Authors: Moran William M. , Pierce Sidney K. 
Published: June 2005

AbstractWhen the rock crab Cancer irroratus is exposed to hypoosmotic artificial seawater (ASW) its muscle cell volume is regulated, in part, by a reduction of the intracellular glycine concentration. Therefore, the effect of reduced ASW osmolarity on the unidirectional glycine influx and efflux of isolated rock crab muscle cells was assessed to determine whether changes in these fluxes might contribute to the decreased intracellular glycine concentration. The glycine influx (extracellular glycine concentration = 1mM) into muscle cells exposed to 60% ASW decreased from 810 nmol/g dry wt × 8 min (100% ASW) to 470 nmole/g dry wt × 8 min, whereas the glycine efflux increased from 3,410 nmole/g dry wt × 8 min (100% ASW) to 5,930 nmole/g dry wt × 8 min. The decrease in influx was due to the reduced osmolarity rather than the reduced Na+ concentration of the 60% ASW. Further, even the total replacement of Na+ (Li+ and Tris substituted) reduced the glycine influx by only 34%. Thus Na+‐coupled glycine influx is not an important factor in adjusting the intracellular glycine concentration of muscle cells exposed to reduced ASW osmolarity. Since under isosmotic conditions glycine efflux exceeds influx by a factor of four, the hypoosmotically induced increase in glycine efflux is largely responsible for the decrease of the intracellular glycine concentration during the initial stages of hypoosmotic stress.
Convergent evolution of reticulate scales
Authors: Brush Alan H. 
Published: June 2005

AbstractStructural proteins of scales with various morphologies were compared. Ventral reticulate scales have soluble proteins that differ from both dorsal reticulate scales and scutellate scales. Ventral reticulate scale proteins are more like those in reptilian scales, whereas both dorsal type scales have proteins of the ϕ‐keratin family found in beaks, claws, and feathers. The morphological similarity in avian reticulate scales is due to convergence as the result of functional requirements.
Light response of cultured melanophores of a teleost adult fish, Oryzias latipes
Authors: Negishi Sumiko 
Published: June 2005

AbstractMelanophores of adult fish of Oryzias latipes in culture exhibited light‐sensitivity. They responded with pigment aggregation to darkness, and with dispersion to light. These responses, which could be repeated more than several times by changing the light intensity, were not affected by α‐ or β‐adrenergic blockers. These facts suggest that melanophores of Oryzias directly respond to light with pigment displacement. The degree of melanosome translocation was changed depending on the intensity of illumination. The most effective wavelength for the induction of melanosome dispersion was near 415 nm, and light with wavelength around 550 nm was scarcely effective. Theophylline (2mM) and cyclic AMP (50 μM) inhibited dark‐induced melanosome aggregation. Such inhibition suggests that light may act as a trigger to induce changes in the intracellular levels of cyclic AMP. Seasonal variation was observed in the light‐sensitivity of melanophores in culture; dark‐induced melanosome aggregation was less significant in winter. These facts suggest that a photoreceptive substance may play a role in the light‐sensitivity of melanophores as a trigger to induce the aggregation of melanosomes.
Changes in the amount of nonhaem iron in the plasma, whole body, and selected organs during the postlarval life of the lamprey Geotria australis
Authors: Smalley S. R. , Macey D. J. , Potter I. C. 
Published: June 2005

AbstractThe concentration of plasma nonhaem iron and the concentration and weight of all nonhaem iron in the whole body and selected organs, together with its partitioning into ferritin and haemosiderin iron, have been measured during the metamorphosis and upstream spawning migration of the Southern Hemisphere lamprey Geotria australis. Some nonhaem iron was lost from the animal during metamorphosis. However, the concentration and weight of nonhaem iron in the liver rose sharply at this time, following its release from important storage sites in adipose tissue and the degradation of larval haemoglobins. The nephric fold of larval and metamorphosing stages contained over 40% of all nonhaem iron in the body at the commencement of metamorphosis. This was predominantly in the form of haemosiderin. While the rise in liver iron during the transition from larva to adult primarily reflected an increase in the weight of ferritin iron, the amount of iron stored as haemosiderin rose conspicuously towards the end of metamorphosis. The rise in ferritin iron in the liver was accompanied by a decrease in ferritin iron in the plasma, which implies that changes in the liver during metamorphosis result in a greater filtering of circulating ferritin. Such a process would account for the very much lower plasma nonhaem iron concentrations which characterise later adult stages. The weight of nonhaem iron increased markedly in the liver and adult opisthonephros and in the whole animal during the nontrophic upstream spawning migration. This was primarily due to a marked rise in ferritin which in turn could be related to the degradation of adult haemoglobins. The concentration of nonhaem iron (54,700 μg/g) and of its ferritin component (52,300 μg/g) in the liver of animals approaching sexual maturity are apparently by far the highest yet recorded for any vertebrate.
Labelling of living mammalian spermatozoa with the fluorescent thiol alkylating agent, monobromobimane (MB): Immobilization upon exposure to ultraviolet light and analysis of acrosomal status
Authors: Cummins James M. , Fleming Alan D. , Crozet Nicole , Kuehl Thomas J. , Kosower Nechama S. , Yanagimachi Ryuzo 
Published: June 2005

AbstractLiving spermatozoa of seven mammalian species were treated with the thiol‐alkylating fluorescent labelling compound, monobromobimane (MBBR). MB‐labelling alone had no effect on sperm motility, nor on the time course or ability of golden hamster spermatozoa to undergo the acrosome reaction when capacitated in vitro. Exposure of MB‐labelled spermatozoa to ultraviolet (UV) light and excitation of the MB fluorochrome resulted in virtually immediate immobilization of the spermatozoa without affecting acrosomal status. UV exposure of unlabelled spermatozoa for up to 30 sec had no effect upon motility. Immobilization of MB‐labelled spermatozoa depended on the midpiece being irradiated, as irradiation of the head alone, or of the more distal parts of the principal piece, had little or no effect upon motility. Labelling with MB followed by immobilization of individually selected spermatozoa was most useful for detailing the course and site of occurrence of the acrosome reaction during penetration of the cumulus oophorus by golden hamster spermatozoa in vitro. In these often hyperactivated spermatozoa, precise determination of the acrosomal status could not often otherwise be made due to the difficulty in visualizing the acrosomal region of a vigorously thrashing, hyper‐activated spermatozoon. This technique should prove valuable in a variety of studies on sperm motility, capacitation and fertilization, and could also be extended to other cell systems.
Normal development of hamster and rabbit eggs fertilized by spermatozoa labelled with the fluorescent thiol alkylating agent, monobromobimane
Authors: Fleming Alan D. , Cummins James M. , Kuehl Thomas J. , Seidel George E. , Yanagimachi Ryuzo 
Published: June 2005

AbstractCauda epididymal spermatozoa of the golden hamster were labelled with the thiol‐alkylating reagent, monobromobimane (MB). Female hamsters underwent uterine insemination with labelled spermatozoa at laparotomy under metofane anesthesia. All 12 females examined between 5 and 54 h postinsemination yielded a total of 83/100 (83%) eggs in the process of fertilization or embryos. Under ultraviolet (UV) exposure all exhibited a fluorescent tail which, in the 4‐ and 8‐cell embryos, could be seen to be fraying or disintegrating. As cleavage progressed, labelled tail components came to be restricted among the blastomeres such that at the 4‐ and 8‐cell stage the tail could be seen in only one to three blastomeres. To study complete development and pregnancy another 12 females received uterine insemination. After recovery from anesthesia (≃ 4 h) these females were mated with a vasectomized male bearing a dominant genetic marker (black eyes) to allow unequivocal determination of paternity in the fetuses and young produced. Seven became pregnant with one female losing her pregnancy about Day 7 of gestation. Two females sacrificed on Day 13 produced 17 normal fetuses and one resorption. Four females delivered 16 young, all normal at birth and in subsequent growth and fertility. In addition, insemination of female rabbits with MB‐labelled spermatozoa yielded normal embryos (50/52 96%) from 3 does on Day 2 and (38/64 60%) from 4 does on Days 4 or 5. Two normal litters (9 bunnies) have delivered from 3 does allowed to carry to term. These results suggest MB‐labelling of the fertilizing spermatozoon does not compromise normal development and may provide a valuable tool to determine the role and fate of some sperm components (non‐nuclear) to the process of development, particularly in the preimplantation embryo.
Taurine transport by the flounder (Pseudopleuronectes americanus) intestine
Authors: King Patricia A. , Goldstein Susanne R. , Goldstein Jonathan M. , Goldstein Leon 
Published: June 2005

AbstractTaurine transport by the flounder gut was characterized in isolated strips of intestine mounted between Ringer's solutions. Taurine was transported into the cell, against its concentration gradient, by a sodiumdependent system present in both the mucosal and serosal membranes. This system appears to be specific for β‐amino acids and is regulated by cyclic nucleotides (cGMP and cAMP). Kinetic analyses indicated that under physiological conditions the magnitudes of the bidirectional taurine uptake rates would favor net absorption of taurine from lumen to blood.
Insulin‐independent controlled physiological morphogenesis of chick muscle from fusion‐capable myoblasts
Authors: Ramírez Oscar , Alemán Victor 
Published: June 2005

AbstractThigh myogenic cells from 11–12‐day‐old chick embryos were cultured continuously in the presence of medium containing no chick embryo extract (CEE). It is known that CEE contains a muscle‐inducing protein of 35,000 daltons. In spite of the absence of embryo extract and provided that calcium, starting at a concentration as low as 3 × 10−4 M, was present in the tested media, typically aligned myotubes with 20 or more nuclei per fiber or abnormal myosymplasts were produced at will. In the first case, the result was systematically obtained when the media were unchanged. Consequently, the cell microenvironment remained undisturbed and therfore was autoconditioned throughout the 7 days of culture. In the second case, the result depended on the feeding schedules. Conversely, no myotubes were formed in cultures in embryo extract‐free medium without calcium, irrespective of the frequency of medium changes. Insulin, a serum factor believed to be involved in syncytium formation process in vitro, was present in all tested media. Undialyzed or dialyzed fetal calf serum (FCS), used for the preparation of the media, contained 11 μunits of insulin per milliliter. The insulin content in all tested media was diluted, however, to one tenth the physiological serum concentration. The hormone did not promote any kind of myoblast fusion in any experiment in which calcium was deleted as a component of the tested media, regardless of the feeding schedule followed. Contrary to former claims, the present results demonstrate that, as in the initial development of chick heart and skeletal muscle in vivo, insulin, which is not produced in significant amounts until day 12 of incubation, does not participate in the early differentiation of skeletal muscle in vitro. These results lend further support to the idea of the existence of an intrinsically ‘fusion‐capable’ myoblast.