bluuebunny/crossref_metadata_2025 huggingface dataset:
Alcohol dehydrogenase and ethanol tolerance at the cellular level in Drosophila melanogaster
Authors: Geer Billy W. , Dybas Linda K. , Shanner Laura J.
Published: June 2005

Exposure of early third instar larvae of Drosophila melanogaster to a nonlethal dose of ethanol was detrimental to larvae lacking alcohol dehydrogenase (ADH) but beneficial to wild‐type larvae in terms of surviving a later ethanol tolerance test, indicating that one of the important functions of the ADH system is to supply derivatives of ethanol to larvae that in turn promote ethanol tolerance. High intracellular concentrations of ethanol in ADH‐deficient (Adhn2) larvae fed ethanol were accompanied by a decrease in the cell membrane infoldings of fat body cells, suggesting that the capacities to absorb and release molecules were reduced. Marked effects of ethanol on the endoplasmic reticulum and mitochondria of ADH‐deficient larvae were also evident. The absence of similar changes in wild‐type larvae that were fed moderate levels of ethanol showed that the ADH system kept the intracellular level of ethanol at a concentration low enough to avoid cell damage. A cytometric analysis of electron micrographs showed that there were ethanol‐induced reductions in glycogen, lipid, and protein stores in the fat body cells of ADH‐deficient larvae fed 1.25% ethanol (v/v) compared with null larvae fed an ethanol‐free diet. This finding implied that the capacities to synthesize or store these compounds may be limited by high intracellular concentrations of ethanol. The cytometric analysis also revealed that the consumption of diets containing 2.5% and 4.5% ethanol by Canton‐S wild‐type larvae for 3 days after 4 days of feeding on an ethanol‐free diet resulted in decreases in glycogen and protein deposits in fat body cells, but increased the amount of lipid deposits compared to larvae fed an ethanol‐free diet. This observation, coupled with the greater weight of wild‐type adults that were fed a growth‐limiting concentration of ethanol compared with control adults, suggested that a metabolic defense mechanism in larvae is to convert toxic ethanol to nontoxic storage products. Dietary ethanol alone and in combination with isopropanol stimulated an increase in the size of the NAD‐pool in larvae, a condition that may favor the activity of ADH. A low dietary level of isopropanol (1%) completely blocked glycogen deposition in wild‐type larvae, whereas ethanol did not. Thus ethanol and isopropanol exert some different toxic effects on larval fat bodies.
Prostaglandin F and E synthesis by specific tissue components of the brook trout (Salvelinus fontinalis) ovary
Authors: Goetz Frederick W. , Duman Priscilla , Ranjan Mukul , Herman Ceil A.
Published: June 2005

The synthesis of prostaglandins (PGs) by several tissue components of brook trout (Salvelinus fontinalis) ovaries was investigated using radiolabeled precursor incorporation and radioimmunoassays for PGE and PGF. PGE2 and PGF2α were synthesized from 14C arachidonic acid (AA) by the follicle walls of mature oocytes. Synthesis was significantly greater in follicles taken postovulation as compared to those sampled prior to germinal vesicle breakdown. However, the most extensive synthesis of PGs occurred with tissue outside of the mature follicles (i.e., extrafollicular[EF]). When incubated with AA, the predominant primary PG produced by this tissue was PGE2. EF tissue could be separated microscopically into two major fractions—immature follicles and stromal tissue. When these tissue fractions were incubated separately with AA the stromal fraction retained the ability to produce PGE2, while the immature follicles increased synthesis of PGF2α. 14C‐Eicosatrienoic acid was converted to PGE1 and PGF1α by EF tissue but in significantly reduced quantities relative to AA. Fatty acid analysis indicated that there were significant quantities of arachidonic, eicosapentaenoic, and docosahexaenoic acids in both follicles and EF tissue, but there was not a significant difference between the two tissues in the absolute amount of arachidonate/mg tissue.

In experiments using radioimmunoassays (RIAs), the highest quantities of PGE were measured in incubates containing EF tissue. This supported the results obtained through arachidonic acid incorporation and suggested that this tissue is the primary source of PGE in the brook trout ovary. In contrast, the mature follicules that were undergoing ovulation in vitro produced significant quantities of PGF, whereas the EF tissue production of PGF, measured by RIA, was very low.

The results clearly indicate that there are several potential sites for PG synthesis within the trout ovary that differ in their capacity to produce E and F prostaglandins.
The effect of tail morphology on locomotor performance of snakes: A comparison of experimental and correlative methods
Authors: Jayne Bruce C. , Bennett Albert F.
Published: June 2005

A combination of experimental and correlative analyses was used to study the effect of tail length on locomotor performance of garter snakes (Thamnophis sirtalis fitchi). Correlative analysis was used to determine whether naturally occurring morphological variation was associated with differences in performance, whereas experimental modification of morphology was used to test whether this variation was a causative factor for different performance. Burst speed of snakes performing terrestrial lateral undulation was measured for snakes with experimentally altered tail length and for snakes with partial and complete tails from a natural population. For 445 snakes with complete tails, regression analysis revealed a significant quadratic effect of relative tail length on size‐corrected performance, indicating that individuals with intermediate relative tail length had the fastest burst speeds. For 52 snakes that had naturally lost from 0.3% to 80.4% of their tail, there was no significant correlation between size‐corrected performance and the extent of the tail that was missing. Experimental ablation of the distal one third of the tail did not affect performance, whereas ablation of the distal two thirds of the tail caused a significant average decrease in speed of only 4.5%. Contrary to the correlative analysis, the experimental manipulation suggests that there is no detectable mechanical effect for minor variations in relative tail length. We conclude that minor deviations from intermediate relative tail length are not the causative factor for a decrement in performance among snakes, and this decrement was a correlated response to some other unmeasured variable.
The stellate layer and rhythmic contractions of the Oryzias latipes embryo
Authors: Cope Jeffrey , Fluck Richard , Nicklas Leena , Plumhoff Lou Anne , Sincock Stephanie
Published: June 2005

The objective of this study was to determine which cells in the medaka (Oryzias latipes) embryo participate in the rhythmic contraction waves that propagate slowly across the yolk sac throughout most of embryonic development. To facilitate observation of the cells, we inhibited the contractions temporarily by incubating the embryos with o‐nitrobenzylacetate, n‐heptanol, or n‐octanol. After we washed out the inhibitor, isolated cells in a subepithelial layer (similar to the stellate layer in Fundulus heteroclitus) began to pulse. Stellate cells are much smaller than cells in the surface epithelium (enveloping layer) and are present throughout the developmental period during which the contractions occur, stage 14 to stage 26. We conclude that the active force for the rhythmic contraction waves is provided by cells in the stellate layer and that cells in the enveloping layer are passively deformed by the contraction of cells in the closely apposed stellate layer.
Insulin cells are found in the main and accessory urinary bladders of the painted turtle, Chrysemys picta
Authors: Gapp David A. , Taranto Robert N. , Walsh Eric F. , Favorito Paul J. , Zhang Yun
Published: June 2005

Insulin has been localized immunocytochemically to cells in the main and accessory urinary bladders of the painted turtle, Chrysemys picta, and represents an unusual addition to the specturm of regulatory peptides associated with the urinary bladder. These stellate to fibroblastoid cells often possess neural‐like processes and are similar in morphology to neurotensin cells found in Chrysemys and Pseudemys urinary bladders. Radioimmunoassay of 2M acetic acid extracts of bladder tissue indicate that the insulin concentration of accessory bladder is several‐fold greater than main bladder but considerably lower than the insulin content of pancreas. Pieces of accessory bladder incubated in vitro exhibit a stable insulin release into the medium over 1 hour, but release is unaltered by known insulin secretagogues. It is tempting to postulate an endocrine or paracrine regulatory function for these cells, but at present their role in Chrysemys bladder function remains unknown.
sn‐1,2‐Diacylglycerol levels increase in progesterone‐stimulated Xenopus laevis oocytes
Authors: Wasserman William J. , Freedman Alan B. , Labella John J.
Published: June 2005

Full‐grown Xenopus laevis oocytes resume meiosis from prophase arrest in response to progesterone stimulation. Recent studies have shown that the tumor promoter, 12‐O‐tetradecanoylphorbol 13‐acetate (TPA), a very potent activator of protein kinase C, can also induce the resumption of meiosis in amphibian oocytes. We have investigated the possibility that sn‐1,2‐diacylglycerol (DAG), the intracellular activator of protein kinase C, may be involved in the pathway normally used by progesterone. We have found that full‐grown oocytes arrested in meiotic prophase contain 48 ± 5 pmoles DAG/oocyte. This level increases within the first 5 minutes following the addition of progesterone and reaches a maximum of 75 ± 10 pmoles following 60 minutes of steroid stimulation. Progesterone induces the up‐regulation of a Na+ /H+ antiport in the plasma membrane of the oocyte causing an increase in pHi following 60 minutes of steroid stimulation. We have found that the addition of 200 μM DAG (1,2‐dioctanoylglycerol, diC8) to the culture medium can cause a partial up‐regulation of this Na+ /H+ pump in the absence of hormonal stimulation. These results suggest that DAG and protein kinase C may be involved in regulating certain aspects of meiotic maturation in progesterone‐stimulated Xenopus oocytes.
Metabolic alkalosis in the larval salamander, Ambystoma tigrinum: Partitioning regulatory responses between the skin and kidneys
Authors: Stiffler Daniel F. , Bachoura Norma
Published: June 2005

Larval Ambystoma tigrinum were non‐occlusively cannulated in the truncus arteriosus for blood collection. One group was infused with a single dose of 1 ml of 200 mM NaHCO3 to induce a metabolic alkalosis. This increased pH from 7.79 to 8.22 after 5 minutes. Bicarbonate ion concentration increased from 16.3 mM to 48.6 mM during this time. After 2 h [HCO3−] was still elevated but pH had returned to control as the PCO2 became elevated. A series of infusions of 1 ml of 200 mM NaHCO3 at 40 minute intervals into a second group of animals produced a prolonged alkalosis that persisted 8 hours. During this period C1− influx increased by 130%. There was a similar increase in C1− efflux resulting in no change in net C1− flux. There was no significant change in Na+ influx, however, Na+ efflux increased by almost 150%. Bicarbonate fluxes were measured directly in a third group of serially infused animals whose cloacae were cannulated to permit partitioning of renal and extra renal routes of HCO3− excretion. There was a significant increase in total HCO3− excretion during alkalosis and 95% of it was extrarenal. Although the kidneys can increase base excretion during metabolic alkalosis their capacity is limited with the great majority of base excretion occurring across the skin and/or gills.
Binding of gonadotropins (GTH I and GTH II) to coho salmon gonadal membrane preparations
Authors: Yan Liguang , Swanson Penny , Dickhoff Walton W.
Published: June 2005

This study was designed to optimize binding conditions of salmon gonadotropins (GTH I and GTH II) to membrane preparations of salmon gonadal tissues. Coho salmon (Oncorhynchus kisutch) GTH I and GTH II were radioiodinated by lactoperoxidase method. Binding conditions were characterized using membrane preparations from coho salmon postovulatory ovaries. The optimal conditions for specific binding were the following: pH 7.5, 20–40 mM MgCl2, 15°C, ⩾ 24 hr incubation time. Specific binding of 125I‐GTH I or 125I‐GTH II can be displaced by (in order of relative potency from high to low) GTH I, GTH II, GTH I β‐subunit, and GTH II β‐subunit. GTH α‐subunit did not displace labeled GTHs, but the mixture of α‐ and β‐subunits. GTH but the mixture of α‐ and β‐subunits was more potent than the β‐subunits alone, indicating that recombination of subunits probably occurred. In membranes of postovulatory ovaries, the affinity of the receptor(s) for GTH I was higher, Kd = 0.87 ± 0.12 nM (mean ± SEM), than that for GTH II, Kd = 2.76 ± 0.33 nM; but the receptor density (capacity) was lower for GTH I (31.02 ± 3.72 fmol/mg protein) than that for GTH II (47.01 ± 4.77 fmol/mg protein). Specific binding for both GTH I and GTH II was also detected in membranes of ovaries and testes of immature coho salmon. These resuls suggest the presence of some shared and some separate binding sites for the two gonadotropins.
Expression of an antigen specific for trunk lateral cells in quarter embryos of the ascidian, Halocynthia roretzi
Authors: Nishikata Takahito , Satoh Noriyuki
Published: June 2005

Cell‐lineage analysis has demonstrated that a pair of the right and left A7.6 cells of a 64‐cell embryo of the ascidian Halocynthia roretzi, descendants of A4.1 cells of an 8‐cell embryo, give rise to trunk lateral cells (TLCs). In this study, in order to investigate cellular mechanisms involved in the specification of TLCs, we have examined the expression of a TLC‐specific antigen in cleavage‐arrested embryos and in quarter partial embryos. Although cleavage arrest of embryos by treatment with cytochalasin B at early stages, prior to and including the 16‐cell stage, inhibited expression of the TLC‐specific antigen, embryos arrested at the 32‐cell stage and at later stages developed the antigen. The only blastomeres exhibiting expression of the antigen were the presumptive TLCs, as predicted by cell‐lineage assignments. When the developmental potential of quarter embryos that originated from four isolated blastomere‐pairs (a4.2, b4.2, A4.1, and B4.1 pairs) of an 8‐cell embryo was examined, the A4.1 quarter embryos, which are developmentally fated to give rise to TLCs, rarely showed evidence of expression of the antigen. Expression of the antigen was not observed in a4.2 and b4.2 quarter embryos, which are not associated with the TLC fate. By contract, expression of the antigen was detected in about a half of the B4.1 quarter embryos which are also not associated with the TLC fate. These results are discussed with reference to the relationship between TLCs and mesenchyme cells.
Inositol 1,4,5‐trisphosphate signals the motile response of fish chromatophores—I. Aggregation of pigment in the tilapia melanophore
Authors: Fujii Ryozo , Wakatabi Hoshitsugu , Oshima Noriko
Published: June 2005

After permeabilization of the cell membrance by the treatment with a surfactant, Brij 58, inositol 1,4,5‐trisphosphate (IP3) was found to be effective in causing aggregation of melanosomes within melanophores in primary cultures of the tilapia, Oreochromis niloticus. Inositol 1‐monophosphate (IP) and 1,4‐bisphosphate (IP2) did not have such an effect. Phentolamine, an alpha‐adrenolytic agent, and prazosin, a more specific alpha1‐blocker, did not interfere with the action of IP3, even though they were effective in antagonizing the aggregation of pigment in response to norepinephrine. It appears, therefore, that IP3 may function as an intracellular physiological mediator in the signal transduction of pigment‐aggregating stimuli, including at least alpha1‐adrenergic stimuli, possibly via the release of Ca2+ from the intracellular compartments in which they are stored.
Comparative survey of blood thyroxine binding proteins in turtles
Authors: Licht Paul , Denver Robert J. , Herrera Brenda E.
Published: June 2005

The nature of plasma thyroxine (T4) binding activity was surveyed in turtles; binding to [125I]T4 was measured on polyacrylamide gel electrophoresis—PAGE—and on minicolumns of Sephadex G‐25. An electrophoretically distinct T4 binding protein was identified in all 8 species of Pseudemys studied and in 3 other genera (Chrysemys, Deirochelys, and Emyoidea) of the same family, Emydidae. Levels of this binding activity were highly variable among individuals, but they consistently showed a similar low relative mobility (Rf) compared to albumin, and a relatively low capacity was indicated by displacement with unlabeled T4. Two emydids (Terrapene, Clemmys) showed a similar slow migrating binding peak, but binding activity was low and not as easily displaced by unlabeled T4. T4 binding to albumins was minimal in most of these emydid species, even when binding to the higher affinity, low capacity component was low or displaced by unlabeled T4 (2.5 μg/ml). In contrast, there was no clear evidence for a similar high affinity, low capacity binding protein in any of the other 19 species representing 13 genera of 8 families from two suborders. In these species, binding activity on Sephadex G‐25 was typically low and binding on PAGE was associated largely with albumin; binding levels for albumins were highly variable. In several nonemydids (from distant lineages), binding activity on Sephadex was elevated and PAGE showed a second binding protein distinct from albumin, but it had high capacity (not readily saturable). Thus, an evolutionary divergence in T4 transport proteins is suggested within Chelonia.
Importance of intromission in maintaining the alternating pattern of male mounting behavior and hemipenis use in the lizard Anolis sagrei
Authors: Tokarz Richard R. , Kirkpatrick Sean J.
Published: June 2005

Previous studies of the lizard Anolis sagrei have shown that males in a series of copulations exhibit a significant alternating pattern of mounting behavior and hemipenis use and that this behavior may be adaptive by increasing sperm transfer. To investigate the role sensory feedback from the hemipenis may play in maintaining this alternation of mounting behavior and hemipenis use, the effects of preventing intromission, interrupting copulation, and controlling which hemipenis is used were examined. Males that were allowed to mount, but not to intromit in the first of two successive matings, or bilaterally hemipenectomized males that were allowed to complete four matings, did not exhibit significant alternation of mounting behavior. Significant alternation of hemipenis use was exhibited by males that were allowed to intromit but were interrupted in copulation immediately after intromission. Males that were allowed to intromit but were forced in the first of two copulations to use either the left hemipenis, the right hemipenis, or the hemipenis that was used in an earlier copulation did not exhibit significant alternation of hemipenis use. These results suggest that the alternation of male mounting behavior and hemipenis use observed in A. sagrei is dependent on a hemipenis being intromitted and which hemipenis is used, but is independent of copulation duration.
Estrogen‐independent growth of mouse vaginal epithelium in organ culture
Authors: Tsai Pei‐San , Bern Howard A.
Published: June 2005

A serum‐free vaginal explant culture system was established to investigate the in vitro effect of estrogen on the growth of mouse vaginal epithelium. Vaginal explants were isolated from 40‐day‐old, ovariectomized BALB/cCrgl mice and cultured in a basal unsupplemented medium or in basal medium plus various doses of 17β‐estradiol. Explants were processed for histology at the end of culture periods or were given 4‐hour pulses of tritiated thymidine at various times and processed for autoradiography. Vaginal epithelium increased 3‐ to 5‐fold in thickness and 2‐fold in the number of epithelial cell layers during 72 hours of culture without estrogen; addition of estrogen did not significantly influence epithelial growth. Keratinization of vaginal epithelium occurred within 48 hours of culture in the absence of estrogen, and again addition of estrogen did not accelerate its appearance. Covering the explants with collagen decreased the estrogen‐independent growth of vaginal epithelium. Autoradiography showed that ca. 70–90% of basal epithelial cells entered S phase during the initial 4 hours of culture and that this number declined rapidly after 48 hours to ca. 20%. Addition of 1.8 nM 17β‐estradiol significantly decreased the labelling index of basal cells at 48 hours, but did not affect the labelling index at 24 and 72 hours. Stromal cells were not labelled at any time. Thus, DNA synthesis, cellular proliferation, and differentiation (keratinization) of vaginal epithelium in organ culture occurred without estrogen and were not stimulated by the addition of estrogen.
Comparative aspects of spermatogenic cell metabolism and Sertoli cell function in Xenopus laevis and mammals
Authors: Risley Michael S. , Morse‐Gaudio Michèle
Published: June 2005

Due to the relative dearth of data regarding somatic cell‐germ cell interactions in the testes of non‐mammalian chordates, functional homologies between Sertoli cells from diverse organisms have been difficult to assess. However, recent developments in non‐mammalian testis cell and organ culture techniques have provided experimental approaches to compare Sertoli cell‐germ cell interactions in different vertebrates. Data from in vitro analyses of Sertoli cell‐germ cell interactions are presented to suggest that Sertoli cells from rodents and the frog Xenopus laevis have similarities in supporting energy metabolism and glutathione metabolism in spermatogenic cells. Comparative in vitro analyses of Sertoli cell functions should provide further insights into the evolution of cell‐cell interactions in the testes.
Aspects of the embryology and neural development of the American lobster
Authors: Beltz Barbara S. , Helluy Simone M. , Ruchhoeft Maureen L. , Gammill Laura S.
Published: June 2005

It is feasible to study the anatomical, physiological, and biochemical properties of identifiable neurons in lobster embryos. To exploit fully the advantages of this preparation and to lay the foundation for single‐cell studies, our recent goals have been to 1) establish a quantitative staging system for embryos, 2) document in detail the lobster's embryonic development, 3) determine when uniquely identifiable neurons first acquire their transmitter phenotypes, and 4) identify particular neurons that may serve developmental functions. Behavioral, anatomical, morphometric, and immunocytochemical studies have led to a detailed characterization of the growth and maturation of lobster embryos and to the adoption of a percent‐ staging system based upon the eye index of Perkins (Fish. Bull., 70:95–99, 1972). It is clear from these studies that the lobster nauplius molts at approximately 12% embryonic development (E12%) into a metanauplius, which subsequently undergoes a complete molt cycle within the egg. This molt cycle climaxes with the emergence of the first‐stage larva shortly after hatching.

Serotonin and proctolin, neurohormones widely distributed in the lobster nervous system, appear at different times in development. Serotonin immunoreactive neurons begin to appear at approximately E10%, with the adult complement being established by E50%. In contrast, proctolin immunoreactive neurons appear later and attain their full complement over a protracted period including larval and juvenile stages. The development of serotonergic deutocerebral neurons and their targets, the olfactory and accessory lobes in the brain, are also examined. The olfactory lobes are forming by E10% and have acquired their glomerulur organization by E50%, whereas the formation of the accessory lobes is delayed; the early rudiments of the accessory lobes are seen by E50%, and glomeruli do not form until the second larval stage.
Cardiac performance of an isolated eel heart: Effects of hypoxia and responses to coronary artery perfusion
Authors: Davie Peter S. , Farrell Anthony P. , Franklin Craig E.
Published: June 2005

The pericardial sac containing the heart was removed from large (2.7–6.3 kg) longfinned eels (Anguilla dieffenbachii). Coronary arteries were cannulated in preparation for perfusion with eel Ringer or red cell suspensions. The hearts were maintained by Ringer perfusion while the performance of the heart was assessed. Responses of the hearts to increases in filling pressure and output pressure were recorded. Maximum cardiac output was 22.3 ± 1.4 ml/min/kg body mass (mean ± 1 SEM; N = 9). The highest cardiac power output was measured at maximum cardiac output and was 3.39 ± 0.32 mW/g ventricle mass (mean ± 1 SEM; N = 9). Eel hearts could sustain output pressures near 80 cm H2O, but cardiac output was reduced and cardiac power output was 1.89 ± 0.24 mW/g ventricular mass (mean ± 1 SEM; N = 9). Maximum cardiac output decreased by 14% when hearts pumped hypoxic Ringer with a PO2 of 11.5 torr. At high input pressures concomitant with high output pressures (80 cm H2O), cardiac power output decreased by 38% upon exposure to hypoxic Ringer. Coronary perfusion of hypoxic hearts with red cell suspensions (mean hematocrit 10.4%) at a rate of 2% of control cardiac output (0.20 ml/min/kg body mass) had no effect on maximum cardiac output. However, coronary perfusion enabled hypoxic hearts to maintain cardiac output when output pressure was raised to 80 cm H2O. Under conditions of high input pressure and high output pressure, power output increased by 20% compared to hypoxic hearts without coronary perfusion. The role of the coronary supply to eel myocardium is discussed in the light of the differences in power output responses of the coronary perfused hypoxic heart to challenges with high filling pressures compared to high‐output pressure challenges. © 1992 Wiley‐Liss, Inc.
In vitro synthesis of oviductal secretory proteins by estrogen‐treated ovariectomized gilts
Authors: Buhi W. C. , Ashworth C. J. , Bazer F. W. , Alvarez I. M.
Published: June 2005

The objective of this study was to identify, characterize, and examine oviductal secretory proteins (OSP) synthesized de novo by whole oviduct (WO), ampulla (A), and isthmic (I) tissue from ovariectomized (OVX), corn oil (CO)‐, estrogen (E)‐, progesterone (P)‐, and E + P‐treated gilts. Oviducts were collected from OVX gilts after CO, E, P, or E + P treatment for 11 consecutive days and tissue was incubated with 3H‐leucine (3H‐leu). Rates of 3H‐leu incorporation into nondialyzable macromolecules by WO explants were greater (P < 0.01) with E‐ compared to CO‐, P‐, or E + P‐treated gilts and greater (P < 0.05) by A explants with E‐ compared to CO‐, P‐, or E + P‐treated gilts. An effect of location was noted, with A having a greater (P < 0.01) rate of incorporation than WO or I. Conditioned culture medium was analyzed by one (1D)‐ and two‐dimensional (2D) sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE) and fluorography. Analyses by 1D‐SDS‐PAGE revealed three major E‐dependent bands (335,000, 100,000, and 80,000 Mr) in WO and A, and one (335,000 Mr) in the I. A 20,000 Mr band found in A was inhibited by E, while a 60,000 Mr band found in the A was induced by P. Analyses by 2D‐SDS‐PAGE resolved major E‐dependent bands 2 (100,000 Mr) and 3 (80,000 Mr) into basic and acidic 100,000 Mr proteins and a 75,000–85,000 Mr protein (pI < 4), respectively, found in WO and A, but not in I. A basic 20,000 Mr protein and an acidic 45,000 Mr complex, both found in A, were inhibited by E. Gel filtration of culture medium revealed a high Mr fraction (> 2 × 106) that was induced by E and was 6.8‐fold greater in medium from A than from I. This study clearly demonstrates that 1) WO and A tissue from E‐treated gilts de novo synthesize and secrete three major proteins (basic 100,000, acidic 100,000, and 75,000–85,000 Mr); 2) these E‐dependent proteins are not found in I or with other treatment; 3) several protein complexes synthesized by A are inhibited by E treatment; and 4) a high Mr fraction, produced primarily in the A, is induced or amplified by E. © 1992 Wiley‐Liss, Inc.
The mechanism of antler casting in the fallow deer
Authors: Goss Richard J. , Van Praagh Andrew , Brewer Peter
Published: June 2005

The process by which antlers are detached from their pedicles was examined histologically in fallow deer castrated in the autumn to induce precocious casting. Osteoclastic erosion across an abscission line between the dead bone of the antler and the living bone of the pedicle was found to be responsible for the separation of the 2. As early as 3 days after castration, osteoclasts and associated lacunae were present on the sides of the pedicle bone. These were then found in progressively deeper locations, by 2 weeks extending across the entire width of the pedicle. Concomitant with the centripetal spread of osteoclasts was the enlargement of Haversian canals, the surfaces of which became lined with osteoclasts. These widening vascular channels within the bone were filled with connective tissue, which in precasting stages formed a mesodermal pad about 1 mm thick. In later stages, a circumferential cleft was excavated beneath the antler burr, and connective tissues from the surrounding pedicle skin invaded the space between the antler and pedicle. After casting, the ingrowing integumental tissues fused with the mesodermal tissues derived from the vascular channels of the pedicle to give rise to an incipient antler bud beneath the scab. The ingrowth of epidermis capable of de novo hair follicle formation gave rise to the future velvet skin that envelops the elongating antler. © 1992 Wiley‐Liss, Inc.
Is the anterior‐posterior axis of the fetus specified before implantation in the mouse?
Authors: Gardner R. L. , Meredith M. R. , Altman D. G.
Published: June 2005

The mouse conceptus is generally held to be radially symmetrical about its embryonicabembryonic axis from the blastocyst stage until the primitive streak appears at the beginning of gastrulation. However, this notion has been challenged by recent observations on conceptuses sectioned in utero which suggest that the blastocyst is already bilaterally symmetrical when it begins to implant. Accordingly, the blastocyst has been assigned an anterior‐posterior axis which appears to persist through gastrulation and is claimed to coincide with the anterior‐posterior axis of the future fetus in both orientation and polarity.

In the present investigation the relationship between these two axes was examined in conceptuses dissected from the uterus early in gastrulation so that it could be determined more accurately than is possible in situ. The anterior‐posterior axis of the conceptus and nascent fetus were found to be either parallel or antiparallel to each other, suggesting that while the orientation of the fetal axis may be specified at the blastocyst stage its polarity is not. © 1992 Wiley‐Liss, Inc.
Purification and characterization of m‐calpain from the skeletal muscle of the amphibian Rana ridibunda
Authors: Sargianos N. , Gaitanaki C. , Beis I.
Published: June 2005

Calpain was purified to apparent homogeneity from the skeletal muscle of the amphibian Rana ridibunda. It is composed of two subunits of 78 and 28 kDa, respectively.

The enzyme exhibits kinetic properties similar to those of mammalian and avian skeletal muscle m‐calpains. Ca2+ requirements for half and maximum activities are 400 μM and 1.5 mM, respectively. It is strongly inhibited by thiol protease inhibitors such as leupeptin, E‐64, and antipain and by alkylating thiol group agents such as iodoacetic acid (IAA), iodoacetamide (IAM), and N‐ethylmaleimide (NEM). Its activity is enhanced by reduced thiols such as dithiothreitol (DTT), cysteine, and 2‐mercaptoethanol. The enzyme is stable in the absence of Ca2+ at 55°C, it displays maximum activity at 25°C, and it shows a broad pH optimum between 6.5 and 7.8. In the absence of Ca2+, various divalent cations such as Sr2+, Mn2+, and Ba2+ strongly activate, while other divalent cations such as Ni2+, Co2+, Cd2+, Zn2+, and Cu2+ have no effect on its activity. In the presence of Ca2+, the cations Sr2+, Mn2+, and Ba2+ show a synergistic effect, while the cations of the other group strongly inhibit the calpain activity. The above data demonstrate that calpain from the skeletal muscle of the amphibian Rana ridibunda is a neutral, Ca2+‐activated thiol protease and that it belongs to the class of m‐calpains. © 1994 Wiley‐Liss, Inc.
Effects of extracellular matrix proteins on macrophage differentiation, growth, and function: Comparison of liquid and agar culture systems
Authors: Armstrong Jason W. , Chapes Stephen K.
Published: June 2005

Both spaceflight and skeletal unloading suppress the haematopoietic differentiation of macrophages (Sonnenfeld et al., Aviat. Space Environ. Med., 61:648–653, 1990; Armstrong et al., J. Appl. Physiol., 75:2734–2739, 1993). The mechanism behind this reduction in haematopoiesis has yet to be elucidated. However, changes in bone marrow extracellular matrix (ECM) may be involved. To further understand the role of ECM products in macrophage differentiation, we have performed experiments evaluating the effects of fibronectin, laminin, collagen type I, and collagen type IV on macrophage development and function. Bone marrow–derived macrophages cultured on four different ECM substrates in liquid culture medium showed less growth than those cultured on plastic. Significant morphological differences were seen on each of the substrates used. Phenotypically and functionally, as measured by class II major histocompatibility molecule (MHCII) expression, MAC‐2 expression, and the secretion of interleukin‐6 (IL‐6) and tumor necrosis factor‐α (TNF‐α), these macrophages were similar. In contrast, bone marrow—derived macrophages cultured in suspension, using agar, showed no difference in growth when exposed to ECM proteins. However, IL‐6 and TNF‐α secretion was affected by fibronectin, laminin, collagen type I, and collagen type IV in a concentration‐dependent manner. We conclude that the ECM products fibronectin, laminin, collagen type I, and collagen type IV have profound effects on macrophage development and function. Additionally, we suggest that an ECM‐supplemented agar culture system provides an environment more analogous to in vivo bone marrow than does a traditional liquid culture system. © 1994 Wiley‐Liss, Inc.
Pattern of cell proliferation in the early stages of arm regeneration in the feather star Antedon mediterranea
Authors: Candia Carnevali M. Daniela , Bonasoro Francesco , Lucca Elisa , Thorndyke Michael C.
Published: June 2005

Arm regeneration in the crinoid echinoderm Antedon mediterranea can provide a very useful model for studying regenerative development. This process can be described as an epimorphic process in which new structures develop from migratory actively proliferating cells. Both the repair and the regenerative phases are due to this fundamental mechanism, which is the only way of recruiting cells to form the cicatricial layer and the blastema. In order to identify the source, the proliferation sites and the recruitment times of these cells, cell proliferation was monitored by employing an immunocytochemical system to detect the thymidine analogue bromodeoxyuridine (BrdU) incorporated by S‐phase cells of the regenerating tissues. On the basis of BrdU incorporation the actively proliferating elements can be identified both close and far from the amputation 1) in the populations of migratory cells which are produced at the level of the brachial nerve and the coelomic wall and 2) in the coelomic epithelium itself. These structures are preferential sources of new cells and give a differential contribution during the repair and the regenerative phases in terms of potential of cell proliferation. © 1995 Wiley‐Liss, Inc.
Assembly of somatic histone H1 onto chromatin during bovine early embryogenesis
Authors: Smith Lawrence C. , Meirelles Flávio V. , Bustin Michael , Clarke Hugh J.
Published: June 2005

We have examined the distribution of somatic histone H1 in bovine oocytes and preimplantation embryos, using an antibody that recognizes histone H1 subtypes present in somatic cells. Immunoreactive H1 was not detectable on the chromosomes of metaphase II of meiosis nor in the nuclei of early cleavage‐stage embryos. In most embryos, immunoreactive H1 was assembled onto embryonic chromatin during the fourth to sixth cell cycle after fertilization. No immunoreactive somatic histone H1 was detected, however, when embryos were incubated in the presence of α‐amanitin beginning early during the fourth cell cycle. These results indicate that somatic subtypes of histone H1 are assembled onto embryonic chromatin in a developmentally regulated manner that requires embryonic transcription. Aphidicolin, an inhibitor of DNA replication, also inhibited the assembly of somatic histone H1 onto chromatin when present at early stages of the 4th cell cycle. It is suggested that, because the bulk of histone gene expression in proliferating cells occurs during DNA replication, expression of genes encoding immunoreactive H1 is inhibited in embryos blocked before or soon after entering the S‐phase. These findings on the control of somatic histone H1 assembly onto chromatin in cattle show a remarkable similarity to those found in the mouse. Such evolutionary conservation suggests that the somatic histone H1 complement of chromatin may regulate critical aspects of chromatin activity during mammalian oogenesis or early embryogenesis. © 1995 Wiley‐Liss, Inc.
Quantifying random measurement errors in Voluntary Observing Ships' meteorological observations
Authors: Kent Elizabeth C. , Berry David I.
Published: June 2005

Estimates of the random measurement error contained in surface meteorological observations from Voluntary Observing Ships (VOS) have been made on a 30° area grid each month for the period 1970 to 2002. Random measurement errors are calculated for all the basic meteorological variables: surface pressure, wind speed, air temperature, humidity and sea‐surface temperature. The random errors vary with space and time, the quality assurance applied and the types of instrument used to make the observations. The estimates of random measurement error are compared with estimates of total observational error, which includes uncertainty due both to measurement errors and to observational sampling. In tropical regions the measurement error makes a significant contribution to the total observational error in a single observation, but in higher latitudes the sampling error can be much larger. Copyright © 2005 Royal Meteorological Society
Impacts of in situ and additional satellite data on the accuracy of a sea‐surface temperature analysis for climate
Authors: Reynolds Richard W. , Zhang Huai‐Min , Smith Thomas M. , Gentemann Chelle L. , Wentz Frank
Published: June 2005

Additional in situ and satellite data improve the accuracy of a blended (in situ and satellite) sea‐surface temperature (SST) analysis using optimum interpolation (OI). Two studies were conducted to evaluate the impacts of in situ and additional satellite data. One study evaluated the adequacy of the recent in situ network. Because of the high coverage of satellite data, in situ data used in the analysis tends to be overwhelmed by satellite data. Thus, the most important role of the in situ data in the analysis is to correct large‐scale satellite biases. Simulations with different buoy densities showed the need for at least two buoys on a 10° spatial grid. This will ensure that satellite biases do not exceed 0.5 °C. Using this criterion, regions were identified where additional buoys are needed.

A second study evaluated the impact of satellite SST retrievals from the tropical rainfall measuring mission microwave imager (TMI) on the OI analysis. The present version only uses infrared satellite data from the advanced very high resolution radiometer (AVHRR) instrument. The results of the intercomparisons showed that both AVHRR and TMI data have biases that must be corrected for climate studies. The addition of TMI data clearly improved the OI analysis accuracy without bias correction, but was less significant when bias correction was used. However, there are areas of the ocean with limited in situ data and restricted AVHRR coverage due to cloud cover, and the use of both TMI and AVHRR should improve the accuracy of the analysis in those areas. Copyright © 2005 Royal Meteorological Society
Objective analyses of sea‐surface temperature and marine meteorological variables for the 20th century using ICOADS and the Kobe Collection
Authors: Ishii Masayoshi , Shouji Akiko , Sugimoto Satoshi , Matsumoto Takanori
Published: June 2005

Data for the 20th century from the International Comprehensive Ocean and Atmosphere Data Set and the Kobe Collection have been used as input data for global objective analyses of sea‐surface temperatures (SSTs) and other marine meteorological variables. This study seeks a better understanding of the historical marine meteorological data and an evaluation of the quality of the data in the Kobe Collection. Objective analyses yield gridded data that are less noisy than observed data, which facilitates handling of historical data. The observed data determine the quality of the objective analyses, and quality control specified for historical data is incorporated into the objective analysis to reduce artificial errors. The objective analyses are based on optimum interpolation and reconstruction with empirical orthogonal functions. The final database produced in this study not only contains analysed values, but also analysis errors and data distributions at each time step of the objective analyses.

The analysis database contains ample information on historical observations, as well as signals of marine climate variations during the century. Time series of global mean marine temperatures and cloud cover include trends linked to global warming, and local peaks appear commonly in all the time series around the 1940s. Sea‐level pressure and sea‐surface wind fields show significant linear trends at high latitudes and over the North Pacific Ocean respectively. These trends seem to be artificial. An SST analysis used widely in climatological studies was verified against HadISST from the Hadley Centre and an SST analysis derived from satellite and in situ observations. El Niño and southern oscillation indices for the century are successfully reproduced, even though observations in the tropics are much rarer before 1950 than after 1950. Copyright © 2005 Royal Meteorological Society
Assessing bias corrections in historical sea surface temperature using a climate model
Authors: Folland Chris
Published: June 2005

Analyses of simulations of variations in global and large‐regional land surface air temperature (LSAT) for 1872–1998 using the HadAM3 atmospheric general circulation model are reported. The analyses are designed to test the accuracy of bias corrections to sea‐surface temperature (SST) used in the Hadley Centre's global sea ice and SST (GISST3.1) data set, the more recent Hadley Centre sea ice and SST (HadISST) data set, and in the underlying Met Office historical SST (MOHSST and HadSST1) data sets. The tests are important because SST corrections considerably affect estimates of the magnitude of global warming since the late 19th century. Two ensembles of simulations were created using GISST3.1 as the lower boundary condition. The first ensemble, of six integrations, was forced using GISST with bias‐corrections applied from 1871 until 1941, and was continued with no bias corrections to 1998. A second ensemble of four integrations, for 1871 to 1941, was forced with uncorrected GISST data. Simulations with uncorrected GISST show a substantial and often highly significant cold bias in simulated global and large‐regional annual mean LSAT changes before 1942 relative to a 1946–65 reference period. By contrast, corrected SST data led to simulations of LSAT changes that are generally insignificantly different from those of observed LSAT in most regions before 1942. Tests on extratropical hemispheric scales generally validate the seasonal variation of the bias corrections, though less clearly before 1890 in some seasons. Issues about the quality of the LSAT data are raised by the results in a couple of regions. Over Australia, the model may have reconstructed LSAT changes using bias‐corrected GISST with greater accuracy than the observations before about 1910. © Crown Copyright 2005. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.
Regime shift in the global sea‐surface temperatures: its relation to El Niño–southern oscillation events and dominant variation modes
Authors: Yasunaka Sayaka , Hanawa Kimio
Published: June 2005

Significant changes of mean state appearing widely in the global sea‐surface temperature (SST) anomaly field have happened five times from the 1910s to the 1990s: 1925, 1942, 1957, 1970 and 1976. Since the regions of change spread over both hemispheres and/or multiple oceanic basins, they can be considered as ‘global regime shifts’. The years of regime shifts are consistent with those of the Northern Hemisphere regime shifts reported by previous studies.

It is also shown that the regime shifts have happened concurrently with El Niño–southern oscillation (ENSO) events, which seems to suggest that the ENSO event acts as a trigger of the regime shift. At the regime shift, the tropical Pacific SSTs change from La Niña (El Niño) to El Niño (La Niña) conditions within 1 year. Further, the ENSO events occur just after the regime shifts begin in the July to September (JAS) season and reach the mature phase in the January to March (JFM) season as a typical evolution of the ENSO events. After that, they continue to at least the next year.

The five regime shifts detected have similar features in their seasonal evolution and persistence of signals. First, the shifts start in the JAS season: an SST change occurs in the eastern and central tropical Pacific, and a change in the mid‐latitudes of the North and South Pacific appears with the opposite sign. Then the shifts in the JFM season. The spatial patterns are similar to those of the JAS season, but signals in the North Pacific become remarkable. These features resemble those corresponding to a series of evolutions of ENSO events, but the signals in the North Pacific and the North Atlantic are much stronger than those of the typical ENSO events. After the shifts have happened, the changes in spatial patterns of SST that occurred at the regime shift persist until the next shift. The persistence of signals is more prominent in the JFM season than in the JAS season.

From a review of the dominant variation modes in global SSTs using empirical orthogonal function (EOF) analyses, four modes are identified: the ENSO mode, the Southern Hemisphere trend mode, the North Pacific (NP) mode, and the Arctic oscillation (AO) mode. In the years when regime shifts occur, the ENSO mode, the NP mode, and the AO mode show significant concurrent phase reversals on the global scale as previously shown in the Northern Hemisphere. These findings provide a possible reason why SST changes in the regime shift are similar but not exactly the same pattern as that of ENSO. Furthermore, it can be considered that a simultaneous phase reversal of the NP mode would suppress the growth of anticyclonic (or cyclonic) circulation in the atmosphere over the western tropical Pacific. This suggests that an ENSO event, which begins with a regime shift, would not reverse its condition and last for the following several seasons. Copyright © 2005 Royal Meteorological Society