bluuebunny/crossref_metadata_2025 huggingface dataset:
Scanning the β‐globin gene for mutations in large populations by denaturing capillary and gel electrophoresis
Authors: Li‐Sucholeiki Xiao‐Cheng , Hu Gengxi , Perls Thomas , Tomita‐Mitchell Aoy , Thilly William G.
Published: June 2005

Separation of mutant from nonmutant DNA sequences of ˜100 bp may be accomplished by using defined denaturing conditions of chemical denaturant and/or elevated temperature during electrophoresis on either polyacrylamide slab gels (denaturing gradient gel electrophoresis, DGGE) or capillary gels (constant denaturant capillary electrophoresis, CDCE). In analysis of mutant directly from a polymerase chain reaction (PCR) product mixture, both have detection sensitivities of approximately 1%. CDCE that facilitates an intermediate mutant enrichment step permits detection of mutants at fractions as low as 2 × 10−6. Here we report the successful application of both approaches to scan for mutations of the human β‐globin gene (HBB) in two human population samples of approximately 5000 persons in the HBB. Using DGGE, the coding region and flanking intronic splice sites of HBB were scanned in a population of 4949 Han Chinese individuals in pool sizes of 48 individual DNA samples. Four point mutations ranging in mutant frequency from 0.5 to 0.0002 were identified. Using CDCE with a mutant enrichment step, these same sequences were scanned in a population of 5028, predominantly African‐American juveniles (<9 years) as a single pooled DNA sample. Three point mutations were identified ranging in mutant frequency from 0.13 to 0.0005. This study shows that both the DGGE/small pool and the CDCE/large pool approaches offer the means to define the fine structure map of genetic variation in large population samples, and with appropriately engineered facilities to provide high throughput, should be useful in pangenomic scans to discover genes carrying casual mutations for common diseases.
Hydrolytically stable, diaminocarboxylic acid‐based membranes buffering in the pH range from 6 to 8.5 for isoelectric trapping separations
Authors: Fleisher Helen C. , Vigh Gyula
Published: June 2005

Diaminocarboxylic acid carrier ampholytes, such as L‐histidine, 2,3‐diaminopropionic acid, L‐ornithine, and L‐lysine, were reacted with glycerol‐1,3‐diglycidyl ether (GDGE) and poly(vinyl alcohol) (PVA) in the presence of sodium hydroxide to produce hydrolytically and mechanically stable hydrogels, supported on a PVA substrate, for use as buffering membranes in isoelectric trapping (IET) separations. The pH values of the DACAPVA membranes were determined with the help of small‐molecule pI markers and proteins and were found to be in the 6 < pH < 8.5 range. The membranes were successfully used to isoelectrically trap small ampholytes, desalt ampholyte solutions in IET mode, and effect the binary separation of chicken egg white proteins.
A theoretical study on the structures and energetics of hypothetical TiM(NCN)3 compounds of the 3d transition metals
Authors: Launay Maxence , Dronskowski Richard
Published: June 2005

Quasi‐ternary cyanamides and carbodiimides of general formula AB(NCN)3 with A ≠ B have neither been predicted nor synthesized. Thus, hypothetical compounds of that kind containing 3d transition metals were considered (A = Ti, B = Mn, Fe, Co, Ni, Cu) by means of density‐functional calculations on 34 structural models, most of which were derived from chemically related phases. After performing structure optimizations based on the local‐density approximation, the relative energetic orderings are rationalized in terms of geometrical factors such as molar volumes and polyhedral connections. Total‐energy generalized‐gradient calculations evidence that the most stable models are enthalpically favored with respect to the elements. Even at ambient temperatures, the ternary phases are predicted as being thermodynamically stable in terms of their Gibbs free formation energies, especially if energetically competing and low‐lying binaries (TiC, TiN) can be excluded by a kinetic reaction control. The best models are characterized by low‐spin magnetic transition metals found in octahedral coordination, and the TiN6 and MN6 polyhedra either share faces or edges. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 1180–1188, 2005
Isolation and characterization of a vitellogenesis‐inhibiting factor from sinus glands of the lobster, Homarus americanus
Authors: Soyez D. , Van Deijnen J. E. , Martin M.
Published: June 2005

A vitellogenesis‐inhibiting (VI) factor has been characterized from extracts of lobster sinus glands (SG) using an in vivo bioassay developed in the shrimp, Palaemonetes varians. After a two‐step purification by reversedphase high‐performance liquid chromatography (RP‐HPLC), the bioactivity is recovered in one symmetrical peak. Sodium dodecyl sulfate‐urea‐polyacryl‐amide gel electrophoresis (SDS‐urea‐PAGE) of the bioactive fractions reveals, after silver staining, the presence of only one band corresponding to a 7—8 kD peptide.
Development of mitochondrion‐rich cells in the yolk‐sac membrane of embryos and larvae of tilapia, Oreochromis mossambicus, in fresh water and seawater
Authors: Ayson Felix G. , Kaneko Toyoji , Hasegawa Sanae , Hirano Tetsuya
Published: June 2005

The development and changes in the activity of mitochondrion‐rich (MR) cells in the yolk‐sac membrane of tilapia (Oreochromis mossambicus) embryos and larvae were examined in relation to environmental salinity. Size and density of MR cells were monitored until complete yolk resorption in embryos and larvae spawned and hatched in fresh water (FW) and seawater (SW), and in larvae transferred from FW to SW or from SW to FW. MR cells were present in the yolk‐sac membrane of embryos 2 days after fertilization and were significantly larger in SW than in FW. In embryos and larvae maintained until complete yolk resorption in FW, the size of MR cells tended to decrease as the larvae grew older, whereas in those maintained in SW, the large size of MR cells was maintained. After direct transfer of newly hatched larvae from FW to SW, the size of MR cells markedly increased, and decreased when newly hatched larvae were transferred from SW to FW. MR cell density did not vary appreciably between larvae in FW and those in SW, and was not significantly affected by transfer of larvae from FW to SW or vice versa. Electron‐microscope examination of MR cells in the yolk‐sac membrane revealed the presence of numerous mitochondria, well‐developed tubular system and apical pits, indicating similarity with MR cells in branchial and opercular epithelia of adult fish. In tilapia embryos, in which the gills, gut, and kidney are not yet fully developed, MR cells in the yolk‐sac membrane are potentially important sites for ion exchange in SW. © 1994 Wiley‐Liss, Inc.
Immunological detection of a vacuolar‐type H+‐ATPase in vanadocytes of the ascidian Ascidia sydneiensis samea
Authors: Uyama Taro , Moriyama Yoshinori , Futai Masamitsu , Michibata Hitoshi
Published: June 2005

Ascidians belonging to the family Ascidiidae are known to accumulate vanadium from seawater in their blood cells, concentrating vanadium by a factor of 107. Among several different types of blood cell, the signet ring cells have both high levels of vanadium and a low pH. These observations suggest the possibility that proton ions concentrated by a H+‐ATPase are energetically linked to the accumulation of vanadium. In the present experiments, therefore, we made an immunological search for a H+‐ATPase in the vacuolar membranes of the signet ring cells, as a first step in our attempts to clarify the energetics of the accumulation of vanadium by these cells. Antibodies raised against the 72‐kDa and 57‐kDa subunits of a vacuolar‐type H+‐ATPase from bovine chromaffin granules reacted with the vacuolar membranes of signet ring cells. Immunoblotting analysis confirmed that specific antigens in ascidian blood cells actually reacted with the antibodies. Furthermore, addition of bafilomycin A1, a specific inhibitor of vacuolar‐type H+‐ATPase, inhibited the uptake of protons by the vacuoles of signet ring cells. Thus, the addition of bafilomycin A1 inhibited the pumping function of the vacuoles of signet ring cells, with resultant neutralization of the contents of the vacuoles. © 1994 Wiley‐Liss, Inc.
Complex tibial organs in the forelegs, midlegs, and hindlegs of the bushcricket Gampsocleis gratiosa (tettigoniidae): Comparison of the physiology of the organs
Authors: Kalmring Klaus , Rössler Wolfgang , Unrast Clemens
Published: June 2005

Complex tibial organs are found in all three pairs of legs of tettigoniids and consist of the subgenual organ, the intermediate organ, and the crista acoustica. In the forelegs of most tettigoniids, the tibial organs in association with tympanic membrane, tracheal tube, and spiracle are highly developed sound transmitting structures (tympanal organs), but not so in the mid and hind pairs of legs (atympanal organs). We have studied the electrophysiology of the atympanal organs and in particular of the intermediate organ and the crista acoustica using extracellular recordings to obtain summed responses to vibratory and acoustic stimuli and single cell recordings from the different receptor cells.

Significant differences in the responses of the receptor cells of the tympanal and atympanal organs were found predominantly in the case of sound stimulation. Whereas the crista acoustica and the distal part of the intermediate organ of the foreleg are very sensitive auditory receptor organs, the same organs in the mid‐and hindlegs appear to respond not at all or only unspecifically to airborne sound stimuli. By contrast, the responses to vibratory stimuli are similar if not identical. The functions of the subgenual organs in all six legs are basically identical, but the function of the middle and distal parts of the crista acoustica in the mid‐and hindlegs remains to be characterized.© 1994 wiley‐lines, Inc.
Effects of larval eyestalk extirpation on morphogenesis and molting in the snapping shrimp Alpheus heterochaelis say
Authors: Knowlton Robert E.
Published: June 2005

Zoea larvae of Alpheus heterochaelis were reared in isolation in the laboratory at selected temperature levels (17, 22, 25, and 27°C) and 32‰ salinity. One or both eyestalks were removed from some animals (experimentals), or antennae from others (operated controls), at various times during larval development. In all experiments virtually all unoperated animals (controls), operated controls, and zoeae lacking one eyestalk exhibited the same abbreviated pattern (three larval “stages” or instars) typical of this species. Ablation of both eyestalks during Stage II always produced an extra “Stage IV” zoea with postlarval features in the abdomen. These animals usually molted again without undergoing substantial structural changes. Ecdyses into the two supernumerary instars occurred significantly earlier than comparable ecdyses (to postlarva and juvenile) among all other experimentals and controls. Bilateral eyestalk removal a few hours before or after the molt to Stage III often generated forms ranging from precocious zoeae to postlarvae (megalopae) with some residual larval features. Some of these individuals subsequently molted into normal postlarvae and juveniles, as did all animals whose eyestalks were removed 12 or more hours into Stage III. Juveniles that developed from eyestalkless larvae were consistently darker (red) than stalked animals. These results suggest that the larval eyestalk contains a factor that promotes metamorphosis, a molt‐inhibiting hormone, and a chromatophorotropin. © 1994 Wiley‐Liss, Inc.
Anterior pituitary and adrenal cortical hormones accelerate or inhibit tadpole hindlimb growth and development depending on stage of spontaneous development or thyroxine concentration in induced metamorphosis
Authors: Wright Mary L. , Cykowski Lori J. , Lundrigan Leanne , Hemond Karen L. , Kochan Dorothy M. , Faszewski Ellen E. , Anuszewski Colleen M.
Published: June 2005

The effect of prolactin, growth hormone, and various adrenal corticoids on hindlimb growth, development, and differentiation was studied in Rana pipiens larvae. Experiments were performed at different stages of spontaneous development and during metamorphosis induced in premetamorphic tadpoles by various concentrations of exogenous T4. Prolactin at 10 μg/day inhibited the limb at spontaneous premetamorphosis, had no effect at prometamorphosis or when administered with 3.8 nM T4, and synergized with T4, at 63 nM T4 and above. Growth hormone (10 or 20 μg/day) promoted limb growth and development during premetamorphosis but had no effect on spontaneous or induced metamorphosis thereafter, nor did it stimulate limb epidermal differentiation. The adrenal corticoids inhibited limb growth and epidermal cell proliferation during pre and prometamorphosis but had no effect on limb morphogenesis or differentiation. The depressive effect of corticoids during spontaneous metamorphosis is at least partly through thyroid inhibition since hydrocortisone significantly reduced follicle cell height, lumen diameter, and cell proliferation in the thyroid. During induced metamorphosis, steroids (0.29 μM), especially corticosterone and aldosterone, antagonized the effect of 0.38 to 1.2 nM T4 on the limb. All steroids except deoxycorticosterone synergized with 3.8 nM T4, and at 31 nM T4, approximating the climax level with permeability factors taken into account, all corticoids synergized with T4 to promote limb growth and development. Aldosterone antagonized T4 at a higher T4 level than the other corticoids. The effect of all steroids except corticosterone was also corticoid dose‐dependent. The results show the importance of the T4 concentration in interactions of T4 with other hormones and suggest a scheme for hormonal control of limb growth and morphogenesis during metamorphosis. During premetamorphosis growth hormone synergizes with low endogenous T4 to promote initial limb growth and development while prolactin opposes this action. During prometamorphosis, as growth hormone and prolactin become ineffective corticosteroids begin to synergize with the rising level of endogenous T4. At climax, prolactin also augments the action of T4 to bring about rapid hindlimb growth. © 1994 Wiley‐Liss, Inc.
Uptake of 3H‐estradiol by embryonic crocodile gonads during the period of sexual differentiation
Authors: Smith Craig A. , Joss Jean M. P.
Published: June 2005

Egg incubation temperature controls sexual differentiation of the gonads in the saltwater crocodile, Crocodylus porosus. Embryos incubated at 30°C develop ovaries and hatch as females while most embryos incubated at 32–32.5°C develop testes and hatch as males. Several lines of evidence suggest that estrogen is involved in gonadal sex differentiation in crocodilians and other reptiles with temperature‐dependent sex determination (TSD). In vivo autoradiography was used here to identify sites of 3H‐estradiol uptake in the urogenital tissues of C. porosus embryos incubated at 30°C (female‐producing) and at 32.5°C (predominantly male‐producing). During the period of gonadal differentiation (developmental stage 23), 3H‐estradiol was specifically concentrated in the gonads of presumptive females at 30°C and presumptive males at 32.5°C. Binding was localised primarily in the medulla of the gonad in both sexes, with little or no uptake in the cortex. No uptake was detected in the adjoining adrenal glands, at either temperature, although some uptake was observed in the mesonephros at the female temperature (30°C). No specific binding of estradiol by the gonads was found prior to (stage 19) or after (stage 28) the period of gonadal differentiation. These results are consistent with the hypothesis that estrogen binding sites are present in the gonads of both sexes during a specific period of embryogenesis, which coincides with the time of gonadal sex differentiation. Furthermore, these observations suggest that the role of estrogen in TSD is not mediated through differential uptake of the steroid by presumptive ovaries and testes. It is therefore hypothesised that estrogen synthesis is temperature‐sensitive, rather than estrogen binding by the gonad. © 1994 Wiley‐Liss, Inc.
Bioluminescence of myctophid and stomiiform fishes is not due to bacterial luciferase
Authors: Haygood Margo G. , Edwards Deeanne B. , Mowlds Gabrielle , Rosenblatt Richard H.
Published: June 2005

A recent report by D. Foran proposes that bioluminescence of myctophids and some stomiiform fishes is due to bacterial symbionts in their photophores, based on positive hybridization of bacterial luminescence (lux) gene probes to DNA from muscle and skin of myctophids and stomiiforms and in situ hybridization. Previous microscopic studies have not revealed the presence of bacteria in these fishes, and bioluminescence of myctophids has been attributed to a coelenterazine‐based system. We have investigated this finding by assay of bacterial luciferase and by lux hybridization to DNA from photophores and control samples in order to determine whether bacterial symbionts or bacterial lux genes are present in these fishes. Results of enzyme assays of photophores from six species of myctophids and two species of stomiiforms show bacterial luciferase activity ranging from 0 to 7 × 105 quanta sec−1 mg wet weight−1. The highest levels detected were 3–4 orders of magnitude less than the activity of luminous bacteria and symbiotic light organ extracts, and were less than or equal to the activity of gut homogenates, which were up to tenfold higher than the highest photophore activities. Hybridization with lux probes did not detect lux sequences in photophore DNA from three species of myctophids and three species of stomiiforms. We find no evidence that bacterial luciferase is the source of luminescence in myctophid and stomiiform light organs.
Presence of soluble tetrameric (blood) and membrane‐bound dimeric forms of cholinesterase in the mollusk Murex brandaris (Gastropoda: Neogastropoda)
Authors: Talesa Vincenzo , Grauso Marta , Principato Giovanni B. , Giovannini Elvio , Norton Scott J. , Rosi Gabriella
Published: June 2005

In the marine snail Murex brandaris about 80% of cholinesterase (ChE) activity lies in the blood. It can be recovered as a fully soluble (FS) form by mincing the whole animal. Two more ChE forms, detergent (DS) and high‐salt soluble (HSS) (18 and 2% of total ChE activity, respectively), can then be sequentially extracted from the other tissues. FS and DS ChEs were purified to homogeneity by affinity chromatography on procainamide‐or edrophonium‐Sepharose respectively. The small amount of HSS prevented a similar purification and an extensive characterization. According to density gradient centrifugation, gel‐filtration chromatography, and SDS‐PAGE, FS ChE is likely a globular tetramer of a 66 kDa subunit (10.8 sedimentation constant [S], 270 kDa). Moreover, it is an amphiphilic form including a hydrophobic domain. DS ChE appears to be a globular dimer of a 66 kDa subunit (5.6 S, 137 kDa). The amphiphilicity of this enzyme is likely due to a phosphatidylinositol on the catalytic subunits, also responsible for detergent interaction as well as cell membrane insertion. Both FS and DS forms hydrolyze propionylthiocholine faster than other choline thioester substrates. They also show high catalytic efficiency with other choline esters as substrates, likely due to a wide and relatively unspecialized conformation of the active site. Immunological cross‐reactivity showed wide structural affinity between FS and DS forms. Antibody‐enzyme bond gave partial inactivation. On the whole, the results suggest that both FS and DS forms likely originate from only one gene. Differences in quaternary structure and solubility could reflect posttranslational modifications or alternative splicing. © 1994 Wiley‐Liss, Inc.
Scaling of the locomotory apparatus and paddling rhythm in swimming mallard ducklings (Anas platyrhynchos): Test of a resonance model
Authors: Clark Brian D. , Fish Frank E.
Published: June 2005

It was hypothesized that the constant propulsive frequencies observed in several paddling animals as they swim at different speeds reflects “resonance‐like” swimming mechanics. This behavior may result if the hydrodynamic load on the paddle is dominated by acceleration‐dependent, rather than velocity‐dependent, terms, and the musculoskeletal system operates with nearly constant stiffness over a large fraction of the propulsive cycle. A model was developed that uses the form of the paddle and the architecture of a representative limb muscle (lateral gastrocnemius) to predict a value proportional to propulsive frequency in mallard ducklings of different size. Fifteen ducklings were videotaped as they swam in a water channel, and the measured frequencies were compared to model predictions. Although the predicted and measured frequencies were highly correlated (r = 0.926), the 95% confidence interval estimated for the intercept of the reduced major axis fit to the points did not span the origin. This lack of proportionality means that even though it could account for much of the observed variation in paddling frequencies, the present model of resonance‐like swimming is not supported. © 1994 Wiley‐Liss, Inc.
Regulation of DNA synthesis in goldfish vitellogenic ovarian follicles by hormones and growth factors
Authors: Srivastava Rakesh Kumar , Van Der Kraak Glen
Published: June 2005

The present study examines the effects of selected hormones and growth factors on deoxyribonucleic acid (DNA) synthesis by goldfish vitellogenic and prematurational full‐grown ovarian follicles in vitro. The synthesis of DNA was assessed from the incorporation of [3H]‐thymidine after preincubation in medium supplemented with fetal bovine serum, followed by a second incubation in serum‐free medium with several combinations of hormones and growth factors. DNA synthesis by vitellogenic ovarian follicles was enhanced by the addition of ovine and porcine insulin (0.4–40 μg/ml) and human recombinant insulin‐like growth factor I (IGF‐I, 12.5–100 ng/ml) and IGF‐II (50–100 ng/ml); the order of potency was IGF‐I > IGF‐II > insulin. The interactive effects of insulin, IGF‐I, and IGF‐II on DNA synthesis by vitellogenic follicles were additive, suggesting that these peptides may act through distinct receptors. By comparison, both insulin (4 μg/ml) and IGF‐I (100 ng/ml) had no effect on DNA synthesis by prematurational full‐grown follicles, suggesting that sensitivity of ovarian follicles to insulin and IGF‐I may change during follicular development. IGF‐I (25–200 ng/ml) and IGF‐II (25–200 ng/ml) had no effect on basal and human chorionic gonadotropin (hCG)‐stimulated testosterone and 17β‐estradiol production by vitellogenic follicles, suggesting that these growth factors may play a role in regulating follicular DNA synthesis but not ovarian steroidogenesis. Carp gonadotropins (cGtH‐I and cGtH‐II), hCG, and 17β‐estradiol also enhanced DNA synthesis by vitellogenic follicles. The effects of hCG and 17β‐estradiol on DNA synthesis were further enhanced in the presence of either insulin or IGF‐I. In conclusion, these data provide convincing evidence of the mitogenic actions of insulin, IGFs, gonadotropins, and 17β‐estradiol, suggesting that these hormones and growth factors may regulate follicular growth and development in the goldfish. © 1994 Wiley‐Liss, Inc.
Allorecognition/xenorecognition responses in Botrylloides (ascidiacea) subpopulations from the mediterranean coast of Israel
Authors: Rinkevich Baruch , Lilker‐Levav Tami , Goren Menachem
Published: June 2005

Examinations of Botrylloides colonies along the Mediterranean coast of Israel have revealed the existence of three distinct morphs (subpopulations, SPs) which differ in some morphological characteristics and life history patterns. Here we study allorecognition and xenorecognition responses expressed by colonies of three SPs, by employing >400 colony allorecognition and xenorecognition assays. SP1 colonies exhibited a new type of nonself response by the formation of giant ampullae, the megaloampullae. These special structures appeared 1–5 days after first ampullae‐to‐ampullae contacts were established, in assays either within SPs or between SPs, and in xenogeneic challenges with Botryllus schlosseri but not with Didemnum. The megaloampullae developed from regular ampullae, which dilated up to 7 times their normal width and 1.5 times their length, but were usually not involved in cytotoxic reactions. SP2 and SP3 colonies produced “fusion‐rejection” responses in within‐SP assays; however, they may develop hemorrhages only when challenged between SPs (also with SP1 colonies) or xenogenetically with B. schlosseri. No xenogeneic response was recorded when the colonies were assayed with Didemnum. The fusion‐rejection response is characterized by reciprocal penetration of ampullae, develops to short‐term blood vessel anastomosis with increased numbers of amebocytes and macrophages, followed by a limited exchange of blood cells, and subsequently terminates in ampullae amputation and cell death. Hemorrhages developed without ampullae penetration. We studied fusion frequencies in SP1 and SP3 colonies collected from an area of 20 × 30 m. Both combinations of within‐SP assays revealed high rates of fusion (12.5 and 35.0%, revealing 30 and 10 allorecognition alleles on the fusibility locus, respectively), but no fusion was recorded in 50 between‐SP assays. The types of allogeneic responses may indicate that SP2 and SP3 are taxonomically closer to one another than to SP1, a conclusion which is not supported by analyzing morphological, ecological, and developmental features characteristic of the three Botrylloides spp. We also discuss here the phenomenon that some invertebrates express repeatability and specifically more than one distinctive nonself reaction, which indicates the complexity of invertebrate immune responses. © 1994 Wiley‐Liss, Inc.
Origin of the oocyte shell membrane of a dasyurid marsupial: An immunohistochemical study
Authors: Roberts Claire T. , Breed William G. , Mayrhofer Graham
Published: June 2005

Polyclonal antibodies were raised against the extracellular coats (mucoid and shell membrane) of unfertilized oocytes and early embryos of a dasyurid marsupial, the fat‐tailed dunnart (Sminthopsis crassicaudata). Indirect immunofluorescence was used to test the specificity of the antibodies to the shell membrane. Streptavidin/biotin immunoperoxidase cytochemistry revealed that precursors of the tertiary egg membranes are secreted by the luminal epithelium of the ampulla, isthmus (including the crypts), utero‐tubal junction, and adjacent endometrial glands. Histochemistry distinguished between the sites of mucoid and shell membrane precursor secretion. The mucoid coat stained positively with Alcian blue at pH 1.0 and 2.5, with Alcian blue at pH 0.2 after performic acid oxidation, and with PAS which was amylase resistant. Some of the luminal epithelial cells of the ampulla and isthmus, as well as its crypts, also stained positively by these histochemical methods but the luminal epithelium of the utero‐tubal junction and endometrial glands were negative for all methods. The shell membrane did not stain with any of the above methods nor with dihydroxy‐dinapthyl‐disulphide (DDD) or ferric ferricyanide but it was eosinophilic and stained positively with the red cytoplasmic stain of Masson's trichrome. Therefore, it is concluded that shell membrane precursors are secreted by the luminal epithelium of the utero‐tubal junction, adjacent glands, and by scattered glands in the anterior region of the uterus but not by any cell population of the oviduct. © 1994 Wiley‐Liss, Inc.
Unusual response of Artemia franciscana embryos to prolonged anoxia
Authors: Clegg James S.
Published: June 2005

Encysted embryos of the crustacean Artemia franciscana are shown to survive at least 2 years of continuous anoxia, a record unequaled by any other free‐living animal. This result, in conjunction with previous findings, supports the possibility that these embryos are an exception to the generality that a constant flow of free energy is required for eukaryotic cell survival, under ordinary conditions of temperature and water content. © 1994 Wiley‐Liss, Inc.
The effect of blocking inputs of the acoustic trachea on the frequency tuning of primary auditory receptors in two species of tettigoniids
Authors: Kalmring Klaus , Jatho Martin
Published: June 2005

The effect of plugging the input structures of the acoustic trachea of the forelegs of two tettigoniid species on the frequency tuning of the auditory receptor cells of the intermediate organ and of the crista acoustica was investigated. This was performed by long‐lasting single cell recordings by which the threshold curves of the cells were studied before and after carrying out manipulations on the ipsilateral slits and/or the spiracles. In some cases the distal tibia was also cut off during the experiments. Plugging the ipsilateral slits and/or the spiracle with Vaseline has different effects on the frequency tuning of the auditory receptor cells. Closing the slits has a relatively small damping effect being uniform in the stimulus frequency range between 2 kHz and 40 kHz. The tuning curves are left basically unchanged apart from a low elevation of the threshold by a few dB. Occluding the ipsilateral spiracle leads to a frequency‐dependent damping on the activity of the receptors, becoming stronger with increase of the stimulus frequency. Generally, the threshold curves are a few dB less sensitive at their characteristic frequencies and the tuning curves are shifted to lower frequencies, whereby the low frequency threshold curve sides of the receptors are more sensitive by about +2dB to +10 dB and the high frequency sides of the neurons are less sensitive by −5 dB up to −30 dB, depending on the stimulus frequency. When calculating the threshold difference from the threshold curves before and after blocking the ipsilateral spiracle in Mygalopsis marki, three groups of receptor cells can be determined. All low frequency receptors and some of the middle range receptors have zero values (i.e., no difference before and after plugging the spiracle) of the threshold differences at 5 kHz. Many middle range receptors and some of the ultrasonic receptors possess zero values at 10 kHz, and some of the ultrasonic receptors even have them at 20 kHz. The conditions in Mygalopsis marki are similar to those in Gampsocleis gratiosa (the species investigated), although, in the latter, the whole effect is transformed to lower frequencies that may result from the different sensitivity of the organs at low frequency level. Gampsocleis gratiosa has a higher proportion of low frequency to high frequency receptor cells in the organs than Mygalopsis marki. The effect of plugging the inputs of the acoustic trachea on the tuning of the auditory receptor cells is explained by a simple (acousto‐mechanical) model of frequency‐induced movements at the receptor row inside the organ. © Wiley‐Liss, Inc.
Seasonal changes of the adrenocortical responses to stress in redpolls, Acanthis flammea, in Alaska
Authors: Wingfield John C. , Deviche Pierre , Sharbaugh Susan , Astheimer Lee B. , Holberton Rebecca , Suydam Robert , Hunt Kathleen
Published: June 2005

Male and female redpolls (Acanthis flammea) showed marked increases in circulating corticosterone up to 1 hour after exposure to a common stress—capture, handling and restraint—indicating that their hypothalamo‐pituitary‐adrenal axis responded to acute stress in a manner similar to that of other vertebrates. We used this protocol as a measure of responsiveness of the adrenocortical cells to acute stress in general and for comparison with gender and across seasons. In both sexes the adrenocortical response to stress was reduced in January (at Fairbanks, 64°N) and maximal when birds were breeding in June at Toolik Lake (69°N). The elevation of circulating corticosterone following capture and handling in breeding males at Barrow (71°N) was significantly less than in breeding males at Toolik Lake. There were also considerable variations among individuals in the intensity of the adrenocortical responses, particularly in the maximum levels of corticosterone attained. This individual variation correlated significantly with fat score and/or body mass in both sexes only in breeding birds at Barrow. This difference may be explained by generally lower, and thus reduced variability in body fat and mass in birds sampled in the warmer climate of Toolik Lake. A similar trend was seen in non‐breeding birds, but this was not significant. Additionally, in January, baseline cortisterone levels in males were correlated with body mass, although this relationship did not hold when both sexes were considered. Body mass and fat score in winter were similar to those of redpolls sampled at Barrow in June. These data suggest that redpolls may be able to adjust their responsiveness to acute stresses in relation to fat stores. Those with greater fat depots had reduced responsiveness to stress. © Wiley‐Liss, Inc.
Reactivated movement of decondensed rat sperm models and a description of their ultrastructure
Authors: Morcos Yvette , Swan Margaret Anne
Published: June 2005

This study aimed at finding optimal conditions to decondense rat sperm nuclear chromatin with minimal damage. This was judged by the ability of the sperm‐tail axoneme in the partially decondensed sperm models to be reactivated. Decondensation was assessed by phase contrast microscopy. Partial decondensation was judged to occur when the bright refractive appearance of the sperm nucleus turned black, and full decondensation when the nucleus turned pale and increased in volume. Demembranation was shown to have occurred by electron microscopy. With 0.03% Triton X‐100 rat caudal epididymal sperm were partially demembranated to produce sperm models. Demembranation using a 0.1% solution of Triton X‐100 was complete, but as with the solution of 0.05% Triton X‐100, resulted in poorer reactivation of the partially decondensed sperm models. Reactivated movement of decondensed sperm models was used to assess the effect of the decondensing agents DTT and heparin. We were only able to achieve reactivation of sperm models that had undergone partial decondensation. Optimal reactivation was obtained after rat sperm models had decondensed in the decondensation solution containing 5 mM DTT, 6 mM EDTA, and 27.3 or 34.1 USP/ml heparin. Concentrations of heparin above or below these values resulted in a decrease in the number of sperm models reactivated. Ultrastructurally, sperm partially decondensed with 5 mM DTT, 6 mM EDTA, and 34.1 USP/ml heparin had their plasma membrane further extracted compared with sperm treated with 0.03% Triton X‐100 alone. Decondensation was greatest in the peripheral regions of the nucleus with extraction of the acrosome but not of the perforatorium. The decondensed regions had a filamentous appearance. This procedure will allow access to sperm nuclear chromatin for experimental manipulation in rat sperm models. © Wiley‐Liss, Inc.
Hatchling sex in the marine turtle Caretta caretta is determined by proportion of development at a temperature, not daily duration of exposure
Authors: Georges Arthur , Limpus Colin , Stoutjesdijk Ros
Published: June 2005

Mean daily temperature in natural nests of freshwater turtles with temperature dependent sex determination is a poor predictor of hatchling sex ratios when nest temperatures fluctuate. To account for this, a mathematical model has been developed on the assumption that hatchling sex depends on the daily proportion of embryonic development that occurs above the threshold temperature for sex determination rather than the proportion of time spent above the threshold. The model predictions are borne out by experiments using the marine turtle Caretta caretta. Average developmental rates, both overall and during the period that sexual differentiation is sensitive to temperature, are unaffected by diel fluctuations about the mean incubation temperature. Sex ratios, on the other hand, were affected by diel fluctuations and ranged from ca. 100% males under regimes 26 ± 0°C and 26 ± 3°C to 100% females for regimes 26 ± 7°C and 26 ± 8°C. These and intermediate sex ratios were in close agreement with model predictions. Demonstration of an impact of temperature on sex, while holding overall developmental rate constant, gives support to hypotheses invoking a direct role for temperature rather than alternative hypotheses invoking overall developmental rate as a more proximal influence on sex. The model explains why mean temperature is a poor predictor of hatchling sex ratios. It urges caution in using “hours above the threshold” for predicting sex ratios, because 1 hr at 1°C above the threshold will not be equivalent to 1 hr at 4°C above the threshold. It provides a general framework for integrating experiments at constant temperatures with those in the field or laboratory using fluctuating regimes. It provides greater scope for exploring how reptiles with temperature dependent sex determination might respond to climatic change or other disturbances to the incubation environment. And it provides an explanation of why secondary factors such a hydric conditions and oxygen potentials might influence hatchling sex, even if temperature acts directly to influence sex ratios rather than through its influence on overall developmental rate. © Wiley‐Liss, Inc.
Hydrogen peroxide generating alcohol and aldehyde oxidases in the giant African land snail, Achatina fulica
Authors: Large Andrew T. , Connock Martin J.
Published: June 2005

Hydrogen peroxide generating alcohol oxidase (membrane bound) and aldehyde oxidase (cytosolic) were detected in tissues of the giant African land snail Achatina fulica. The highest specific activities were found in the kidney followed by the digestive gland. Solubilised digestive gland alcohol oxidase had a pH optimum of approximately 7.2. The enzyme oxidises a broad range of aromatic and aliphatic (C2C16) primary alcohols. Subcellular fractionation of digestive gland homogenate indicates that alcohol oxidase is most likely located in the endoplasmic reticulum. Cytosolic aldehyde oxidase was active with aromatic and aliphatic aldehyde but is not active with purines. A digestive role is suggested for these two enzymes. © Wiley‐Liss, Inc.
Mechanism of defensive inflation in the chuckwalla, Sauromalus obesus
Authors: Deban Stephen M. , O'Reilly James C. , Theimer Tad
Published: June 2005

The chuckwalla, Sauromalus obesus, avoids predation by wedging itself in a rock crevice and inflating its lungs beyond their normal inspiratory volume. Buccal and pulmonary pressures were recorded in S. obesus during defensive inflation and wedging. Maximum pulmonary pressure generated during defensive wedging was significantly higher and was achieved faster than that of nonwedging inflation. During inflation and wedging, S. obesus forces air into the lungs by pulsatile contraction of the buccal cavity. Buccal pulse pumping is an ancestral ventilation behavior of vertebrates that S. obesus uses for defensive inflation. © Wiley‐Liss, Inc.
Influence of estrogen on intermediary metabolism in a teleost, Anabas testudineus and the lizard Calotes versicolor
Authors: Kaippallil Jose D. , Oommen Oommen V.
Published: June 2005

Administration of different doses of estrogen (5, 10, and 25 μg) in Anabas testudineus and Calotes versicolor inhibited the activities of alanine aminotransferase and aspartate aminotransferase. In Calotes, higher doses of estrogen (10 and 25 μg) increased the activity of glutamate dehydrogenase and in Anabas it was stimulated by all three doses. The total protein and RNA were also increased by all three doses of hormone in Anabas and Calotes. Higher doses of estrogen stimulated total DNA in Anabas and Calotes and the lowest dose (5 μg) did not have any significant effect. Activities of transaminases and glutamate dehydrogenase were inhibited and the protein content decreased by the administration of actinomycin and puromycin or simultaneous administration of estrogen and protein synthesis inhibitors. Actinomycin and puromycin alone did not have any significant effect on total DNA in Anabas and Calotes. Actinomycin reduced the level of RNA and puromycin did not produce any significant effect in Calotes. In Anabas actinomycin as well as puromycin decreased total RNA content. Simultaneous administration of estrogen and these inhibitors prevented the hormone mediated increase in the level of RNA and DNA both in Anabas and Calotes. © Wiley‐Liss, Inc.
Evolution of immunity: Potential immunocompetence of the echinoid axial organ
Authors: Larson Maureen K. , Bayne Christopher J.
Published: June 2005

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

The female reproductive profile of a fertile genetically obese line of rats, named β, is characterized. Hypophysis, ovaries, oviducts, and uteri weights do not differ from those of nonobese controls. Histological features in ovary, uterus, and vagina in β line and α controls are similar, in agreement with classical descriptions in the subject.

Vaginal opening, number of estrus, number of corpora lutea at ovulation time, and pregnancy patterns (i.e., ovary weight, number of corpora lutea, sites of implantation, and living fetuses, as well as productivity, fertility, litter size, and preweaning mortality) show no significant differences between obese and nonobese animals.

From a reproductive standpoint, obese β line would behave as nonobese. Up to now β would represent the only fertile genetically obese line of rats, appearing as a profitable biological model to widen and deepen reproductive analysis on obesity. © Wiley‐Liss, Inc.
Ontogeny of cardiac function in the brine shrimp Artemia franciscana Kellogg 1906 (Branchiopoda: Anostraca)
Authors: Spicer John I.
Published: June 2005

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

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

The absorption of high kinetic energy by a small amount of material depends not only on the quality of the material but also on the structural design of the elements involved. Using a rapid response microbalance, we measured the tensions of radial threads in webs of the garden cross spider, Araneus diadematus. We also measured the stress‐strain characteristics of dry radius and wet spiral threads laid down by A. diadematus, as well as of the very different and dry spiral threads laid down by the hackled‐band weaver, Uloborus walckenaerius.

The radius threads of A. diadematus showed good extensibility (e = 39. 4%), high tensile strength (s = 1153. 8 MPa) and large hysteresis (56%) which indicates that they can function as shock absorbers and structural elements. Although fewer radii were built in the upper than in the lower half of the Araneus web, our method found no systematic difference between the average pretensions of individual radius threads in these two halves. However, pretension in the upper half of the web showed greater variation.

Orb weavers employ two different mechanisms to increase the energy‐absorbing capacity of their respective capture spirals. The sticky spiral of Araneus diadematus absorbed energy by large extensibility (about 475%) of the wetted thread which developed substantial force only after 100–200% extension, and the entire thread failed suddenly. The hackled band of Uloborus walckenaerius had shorter extensibility (about 125%) and it absorbed energy by friction of the fine hackled fibres, many of which needed to break in succession before a thread failed. © 1995 Wiley‐Liss, Inc.