bluuebunny/crossref_metadata_2025 huggingface dataset:
Calcium‐dependent proteolysis in crustacean claw closer muscle maintained in vitro
Authors: Mykles Donald L.
Published: June 2005

An organ culture system was developed to determine the role of calciumdependent proteinases (CDPs) and lysosomes in the degradation of proteins in the claw closer muscle of the land crab, Gecarcinus lateralis. Elevating intracellular calcium concentrations with caffeine, dibucaine, or ionophore A23187 stimulated proteolysis, as measured by the release of primary amines and tyrosine to the culture medium, 69 to 192%; A23187 also stimulated the degradation of actin and myosin heavy chain in the intact tissue. Cysteine proteinase inhibitors (leupeptin; L‐trans‐epoxysuccinyl‐leucylamido‐(3‐methyl)butane or Ep‐475; ethyl(+)‐(2S,3S)‐3‐[(S)‐methyl‐1‐(3‐methylbutylcarbamoyl)‐butylcarbamoyl]‐2‐oxiranecarboxylate or EST) suppressed proteolysis 24 to 53% while pepstatin A, an inhibitor of aspartic proteinases, and lysosomal inhibitors (chloroquine, 3‐methyladenine, monensin) had no effect. EST also suppressed, by 30 to 35%, A23187‐stimulated release while chloroquine did not; A23187‐stimulated hydrolysis of myosin heavy chain was inhibited 26% by EST and Ep‐475. The myosin heavy chain fragment pattern in supernatant fractions resembled that produced when CDPs were incubated with myofibrils in vitro; both lacked a 145‐kDa fragment produced in reaction mixtures containing purified myosin. This suggests that CDPs degrade in situ myosin polymerized into thick myofilaments rather than myosin monomers. Ultrastructural studies showed that A23187 also induced a preferential removal of the Z‐line. These results are consistent with the hypothesis that CDPs, but not lysosomes, are involved in the turnover of myofibrillar and non‐myofibrillar proteins in crustacean striated muscle.
Analysis of the inhibitory effect of inorganic phosphate on development of four‐cell hamster embryos in vitro
Authors: Monis Helena , Bavister Barry D.
Published: June 2005

Hamster 4‐cell stage embryos were cultured in a protein‐free, glucose‐free medium to study the nature of developmental inhibition by inorganic phosphate (Pi). In the absence of Pi, between 40 and 55% of embryos were able to develop to the blastocyst stage but addition of Pi to the medium reduced this proportion to 5–20%. The inhibition did not appear to be due to contamination of the Pi salt with heavy metals because EDTA did not relieve the effect. Inhibition by Pi showed no dose‐response relationship over the range tested (1–350 μM). In contrast, another divalent anion (sulphate) produced no inhibition of 4‐cell embryo development at concentrations as high as 5.6 mM. Embryos were less sensitive to inhibition by Pi after the third cleavage division had occurred, and development of mid or late 8‐cell embryos was unaffected by Pi. After exposure to Pi for 1 h, embryos could recover and continue development but longer exposure was detrimental to subsequent development. These results indicate that the inhibitory effect is specific to phosphate ions, is not due to contaminants in the Pi salt, is evoked by very low concentrations of Pi, is stage‐specific, and is reversible following brief exposure of embryos to Pi. These effects may be artifacts of the culture milieu, or they may reflect some unknown characteristic of the early cleavage stage hamster embryo.
Fatty acid synthesis and accumulation rates in daphniids
Authors: Goulden Clyde E. , Place Allen R.
Published: June 2005

Fatty acid accumulation and synthesis rates were measured in two species of daphniid Cladocera, Daphnia magna and D. pulex, to determine what fraction of deposited fatty acids accumulated by these zooplankton species are dietary and what fraction are synthesized de novo. Fatty acid accumulation rates were measured as the increment in lipid weight during the adult third instar. Lipids were extracted, separated on chromarods, and quantified by flame‐ionization detection. Fatty acid synthesis rates were measured by exposing adult third‐instar females to [3H]2O and [U‐14C]‐acetate. Synthetic rate estimates using [U‐14C]‐acetate were consistently less than estimates obtained by using [3H]2O. Lipid content (percent of dry weight) from D. magna cultures supplied with high algal food (100,000 cells/ml) increased from 16.6% at the beginning of the third instar (eggs removed from brood pouch) to 22% at the beginning of the fourth instar (with eggs). The increase in lipid of D. pulex under identical conditions ranged from 19.8% to 30.6% total lipid and under low food conditions (4,000 cells/ml) ranged from 37% to 40% lipid. Accumulated fatty acids were associated largely with triacylglycerol (60–80% of accumulated lipid) or phospholipid (10–20% of accumulated lipid). Fatty acid accumulation for high‐food animals was 1,043 ng/hr/individual and 364 ng/hr/individual for D. magna and D. pulex, respectively. The corresponding fatty acid synthesis rates were 17 ng/hr/individual and 6 ng/hr/individual, respectively. Low‐food adults of D. pulex accumulated fatty acids at a rate of 192 ng/hr/individual and only synthesized fatty acids at a rate of 0.3 ng/hr/individual. Incorporated label was present in a slow turnover pool of complex polar lipids. Fatty acid synthesis contributes less than 2% of the accumulated total fatty acids in these daphniids.
Differentiation in vitro of sea urchin micromeres on extracellular matrix in the absence of serum
Authors: Benson Steve , Chuppa Sandy
Published: June 2005

Previous investigations have demonstrated that differentiation in vitro of micromeres from sea urchin embryos requires the presence of serum. In this report we demonstrate that differentiation of micromeres, as judged by their ability to form spicules, will occur in the absence of serum if the cells are cultured on a reconstituted extracellular matrix prepared from Engelbreth‐Holm‐Swarm (EHS) tumors. These results suggest that a permissive environment provided by the EHS matrix is sufficient to induce micromere differentiation and may allow the isolation and characterization of the active component.
Behavior of rabbit dental tissues in heterospecific association with embryonic quail ectoderm
Authors: Fuenzalida Marcela , Lemus Roxana , Romero Sergio , Fernandez‐Valencia Rafael , Lemus David
Published: June 2005

The behavior of dental tissues from the rabbit, Oryctolagus cuniculus, in association with epithelium from the quail, Coturnix coturnix japonica, has been examined. Adult and embryo rabbits were employed in this study. Dental papillae from teeth at the cap stage from rabbit embryos and dental pulp from adult rabbits were isolated surgically and recombined with skin ectoderm from 72‐hour‐old quail embryos. The recombined tissues were cultured for 48 hours on semi‐solid medium and subsequently removed and placed on chorio‐allantoic membranes of 7‐day‐old chick embryos. Control cultures (dental pulp, dental papillae, and quail ectoderm) showed regression, atrophy, or differentiation according to the phenotype of the tissue. After 8 days in explant culture, heterologous recombinants composed of dental papillae and flank skin ectoderm from quail embryos developed differentiated chimeric tooth structures. It was unclear whether or not enamel was being secreted. The fact that the interactions between the enamel epithelium and the dental papillae are reciprocal is well known. The differentiation of odontoblasts can only occur in the presence of an enamel organ. Thus, the quail epithelium must have been induced to become an enamel organ, the lack of enamel proteins notwithstanding. Apical pulp and root pulp from adult rabbits plus quail ectoderm showed a high degree of regression and atrophy. At around 15 days of gestation, the rabbit dental papillae at the cap stage have already acquired odontogenic potential. By contrast, under the same experimental conditions, the dental pulp from continuous‐growth teeth from adult rabbits did not show odontogenic potential. It may be that, under less stringent experimental conditions (for example, in combinations of rabbit embryonic epithelium or first‐arch epithelium from quail embryos with pulp from adult rabbits), other results might be obtained.
β‐keratin expression in avian tongue cell aggregates
Authors: Carver W. E. , Knapp L. W. , Sawyer R. H.
Published: June 2005

Rotation‐mediated aggregation was used to test the capacity of early embryonic tongue cells from different regions of the tongue to reorganize histotypically and terminally differentiate in vitro. Cells dissociated from the anterior ventral (AV) or posterior ventral (PV) surface of the 12 day embryonic tongue were cultured 6 days, fixed, and embedded in paraffin. Indirect immunofluorescence microscopy was used to demonstrate the occurrence and distribution of β‐keratins, the presence of which represented regional and differentiation specific markers of late tongue development. Aggregates of AV cells were organized into a β‐keratin‐producing stratified epithelium. Similar PV aggregates formed only an α‐keratin‐producing stratified epithelium. The epithelial cells of these tongue tissue constructs expressed α‐ and β‐keratins in a manner consistent with the temporal and histotypical expression of keratins observed in vivo.
Accessibility of the insect nervous system to a neurotoxic polypeptide
Authors: Fishman Lena , Kagan Michael L. , Zlotkin Eliahu
Published: June 2005

The binding and accessibility of an insect selective neurotoxic polypeptide derived from scorpion venom (AaIT, Mr = 8 kDa) to the cockroach nervous system was studied by the aid of binding assays and light microscopy autoradiography resulting in the following information:

The toxin possesses high paralytic potency to the cockroach (ED50= 4 ng per 100 mg of body weight) and high binding capacity (13.8 ± 1.8 pmol per mg protein) to its nervous system.

When incubated with dissected and anatomically desheathed central nervous tissue the radioiodinated toxin ([125I]AaIT) revealed an obvious high affinity binding specificity. In contrast, the skeletal muscles of the cockroach were completely devoid of specific binding sites of the [125I]AaIT. The latter observation provides additional support for the sodium channel selectivity of the AaIT toxin.

Autoradiography of [125I]AaIT injected into the body cavity in doses inducing a fast paralysis revealed that the central and most parts of the peripheral nervous system are impermeable to the toxin.

In the above injection assays the toxin was shown to bind to the terminal branches of motor nerves at their close proximity to the skeletal muscles. Computerized image analysis of the autoradiographical data followed by electron microscopy of the neuromuscular junctions suggest an accessibility of the terminal axonal membranes to the toxin.

The above data, supported by previous electrophysiological studies, led to the conclusion that the peripheral terminal outbranchings of the motor nerves serve as the main sites of accessibility to paralytic polypeptide neurotoxins.
Involvement of protein kinase C in the regulation of oocyte maturation in amphibians (Rana dybowskii)
Authors: Kwon Hyuk B. , Lee Won K.
Published: June 2005

Ovarian oocytes of Rana dybowskii, isolated early in the hibernation period (late autumn), failed to mature, i.e., germinal vesicle breakdown (GVBD), in response to progesterone during in vitro follicle culture. Oocytes collected during the middle hibernation period matured in response to progesterone, whereas those collected late during the hibernation period (close to the breeding season) underwent spontaneous maturation without added hormone (Kwon et al., '89). The maturational response (GVBD) of oocytes, collected at the three stages of hibernation, to protein kinase C (PKC) activation was investigated and compared to that of progesterone stimulation. A phorbol ester, phorbol 12‐myristate 13‐acetate (TPA) was used for PKC activation. TPA addition to cultured follicles collected during the early or middle period of hibernation induced oocyte GVBD. The incidence of maturation (% GVBD) induced by TPA varied markedly between animals. TPA (10 μ) induced oocyte maturation in the presence or absence of follicle cells. The time course of the TPA‐induced maturation was similar to that of progesterone‐stimulated maturation (ED50, 7–9 h). TPA also accelerated the onset of maturation of the follicular oocytes exhibiting spontaneous in vitro maturation. Both TPA‐ and progesterone‐stimulated maturation was blocked by treatment with cycloheximide (1 ng/2 ml), forskolin (9 μ) (an adenylate cyclase stimulator), and verapamil (0.27 mM) (a calcium transport blocker). Treatment of oocytes with a calmodulin antagonist N‐(6‐aminohexyl)‐5‐chloro‐1‐naphthalenesulfonamide (W‐7 (100 μ) or a PKC inactivator 1‐(5‐isoquinolinylsulfonyl)‐2‐methyl‐piperazine (H‐7 (50 μM) likewise suppressed TPA‐ or progesterone‐induced maturation. The data suggest that PKC plays a role in the regulation of amphibian oocyte maturation and that the seasonal change in responsiveness (GVBD) of oocytes to steroid occurs after oocytes obtain responsiveness to PKC activation.
Isolation of ice nucleating active bacteria from insects
Authors: Lee Richard E. , Strong‐Gunderson Janet M. , Lee Marcia R. , Grove Kimberly S. , Riga Tammy J.
Published: June 2005

In preparation for winter many insects enhance the supercooling capacity of their body fluids by 25°C or more, thereby avoiding the lethal effects of tissue freezing. A primary factor limiting supercooling capacity is the presence of nucleating agents that catalyze ice formation at high subzero temperatures. Two species of ice nucleating active (INA) bacteria, Enterobacter agglomerans and Enterobacter taylorae, the latter with previously unknown ice nucleating activity, were isolated from the gut of two species of field‐collected beetles, Ceratoma trifurcata and Hippodamia convergens. Ingestion of these INA bacteria greatly diminished the capacity of our insect model, H. convergens, to supercool and caused freezing at temperatures as high as ‐ 1.5°C. Removal or masking of endogenous INA bacteria may be a major factor in the cold‐hardening of freeze intolerant insects for winter survival. Furthermore, these bacteria may provide a novel biological insecticide to control overwintering pest insects by decreasing their natural capacity to supercool.
Valency of vanadium in the vanadocytes of Ascidia gemmata separated by density‐gradient centrifugation
Authors: Hirata Junko , Michibata Hitoshi
Published: June 2005

The amounts of total vanadium and vanadyl (+4) species contained in each blood cell type of ascidians were determined under a nitrogen atmosphere, using a combined approach of cell fractionation and vanadium measurement by ESR spectrometry. The vanadium‐containing blood cells, the so‐called vanadocytes, were the signet ring cells in Ascidia gemmata as well as A. ahodori and A. sydneiensis samea. Among several types of blood cell, only the vanadocyte contained vanadium in both +3 and +4 oxidation states, with a ratio of 97. 6:2. 4. The oxidation state of vanadium in the vanadocyte remained constant during the process of cell separation. Further, the oxidation state did not change in the presence of air, provided the cell did not suffer damage.
Ontogeny of the olfacto‐retinalis projection in coho salmon (Oncorhynchus kisutch)
Authors: Ebbesson Sven O. E. , Meyer Dietrich L. , Malz Cordula R. , Bazer Gary T.
Published: June 2005

Filling of nucleus olfacto‐retinalis neurons by cobaltous lysine injections into one eye of coho salmon of different ages revealed that the terminal nerve projection to the retina is established when the fish leave their freshwater environment. At this time salmons go through a metamorphosis termed “smoltification”. FMRF‐amide‐like immunoreactive neurons in the nucleus olfacto‐retinalis already exist in pre‐smolts before the retino‐petal projection is established. Thus, for the first time in any vertebrate, a projection of the terminal nerve is shown to develop during an advanced ontogenetic state.
Hormonal and physiological control of clutch size, egg size, and egg shape in side‐blotched lizards (Uta stansburiana): Constraints on the evolution of lizard life histories
Authors: Sinervo Barry , Licht Paul
Published: June 2005

We present comparative data from studies of natural populations and experimental manipulations addressing the control of clutch size, egg size, and egg shape among three populations of side‐blotched lizards, Uta stansburiana. On a geographic basis, females from northern populations located in the Coast Range of California produced small clutches of large eggs compared to populations from more southern locations (as little as 60 km farther south). A similar tradeoff between clutch size and egg size was observed among individuals within a population, females that lay large eggs tend to produce small clutches; on a seasonal basis, females laid smaller clutches consisting of larger eggs later in the reproductive season.

Injections of ovine follicle‐stimulating hormone (FSH) into vitellogenic females increased the mean clutch size (from 4.2 to 6.0 eggs) with a concomitant decrease in egg mass (from 0.43 to 0.33 g). By contrast, a surgical reduction of clutch size (yolkectomy of two follicles) caused an increase in egg mass (from 0.43 to 0.53 g)—egg shape changed (elongation) with egg hypertrophy. This increase in egg mass was due largely to increased yolk; hatchlings from these hypertrophied eggs were proportionately heavier than those from control eggs. Egg size was independent of the time course of follicular development (time to oviposition from the onset of yolking averaged 29 days).

These complementary manipulations indicate that (1) the number of eggs in the clutch is under the control of circulating plasma gonadotropin concentrations, and (2) the size of eggs is set by the number of follicles undergoing vitellogenesis and finally ovulated. Moreover, the effect of manipulations was dependent on the stage of vitellogenesis: production of large clutches of small eggs did not occur in females if administration of FSH commenced when follicles were above 4–5 mm in diameter (ovulation normally occurs at 8 mm), and some females undergoing yolkectomy during early vitellogenesis recruited new follicles.
Effects of hypoxia on acid‐base balance, blood gases, catecholamines, and cutaneous ion exchange in the larval tiger salamander (Ambystoma tigrinum)
Authors: Talbot Colleen R. , Stiffler Daniel F.
Published: June 2005

The effects of hypoxia on acid‐base balance and blood gases were examined in larval Ambystoma tigrinum. Environmental hypoxia (P = 24 mm Hg) resulted in a severe metabolic acidosis. During approximately 4 hr of hypoxia, arterial P fell from 23 to 8 mm Hg while P did not change; plasma lactate concentrations rose from 1.7 to 11 mM; pH fell from 7.9 to 7.3 and [HCO3−] decreased by 8.2 mM. After restoration of normoxia, P rose to 40 mm Hg within 1 hr. All variables returned to control levels between 4 and 24 hr. Circulating levels of norepinephrine were significantly increased and highly correlated with pH after 4 hr of hypoxia. Net and unidirectional Na+ and Cl− flux rates were measured before, during, and after hypoxia to determine if cutaneous ion exchange is associated with the acid‐base disturbance. Neither Na+ nor Cl− flux rates changed significantly during hypoxic exposure or recovery.
Developmental analysis of the facets, a group of intronic mutations at the Notch locus of Drosophila melanogaster that affect postembryonic development
Authors: Markopoulou Katerina , Artavanis‐Tsakonas Spyros
Published: June 2005

The activity of the Notch locus of Drosophila melanogaster during embryogenesis is necessary for the correct segregation of neural from epidermal lineages. The action of Notch is not confined to embryogenesis but is also essential for normal development during the postembryonic stages. Its action is pleiotropic, as revealed by the existence of several classes of mutations which affect various imaginal structures. Here, we examine a group of six recessive mutations, the facets (fa, fa3, fag, fag−2, fafx and fasw), which affect eye and optic lobe morphology and have been previously shown to be associated with the insertion of transposable elements into an intronic region of Notch. Using both somatic recombination and gynandromorph analysis, we find that their behavior in a mosaic analysis is not identical. While in the majority of alleles abnormal Notch function in the retina is sufficient to induce optic lobe abnormalities, in the case of fag−2, a considerable number of individuals having mosaic retinas exhibit normal optic lobe structure. All the facet alleles appear to behave in a cell‐autonomous manner. A developmental analysis of the eye and optic lobe defects associated with the facet mutations support the contention that Notch may be involved not only in the formation of certain structures but also in their maintenance.
Activation of the serotonergic system in chick spinal cord during hatching
Authors: Summers Tangi R. , Summers Cliff H. , Desan Paul H. , Smock Timothy K.
Published: June 2005

The objectives of the present study were to determine the levels of serotonin (5‐HT), its major catabolic metabolite, 5‐hydroxyindoleacetic acid (5‐HIAA), and norepinephrine (NE) in chick spinal cord before, during, and after hatching and also to determine if changes in the levels of these chemicals are directly related to the hatching behavior. The levels of 5‐HT, 5‐HIAA, and NE were measured by high performance liquid chromatography with electrochemical detection in whole spinal cords of 20‐day‐old “pre‐hatching” embryos, 21‐day‐old “normal hatching” embryos, 0‐day‐old “post‐hatching” chicks, and 0‐day‐old “glass egg hatching” chicks. NE was measured but no significant differences were found in NE levels among experimental groups. The concentration of 5‐HT was elevated in chick embryo spinal cords during normal hatching compared to pre‐hatching embryos and post‐hatching chicks. The concentration of 5‐HIAA was elevated during and after normal hatching compared to pre‐hatching embryos. However, neither 5‐HT nor 5‐HIAA levels were found to be elevated in chick spinal cords during glass egg hatching compared to pre‐hatching embryos or post‐hatching chicks. Therefore, there appears to be an activation of the serotonergic system in chick spinal cord related to the specific event of hatching but this activation is not directly related to the movements common to both hatching and glass egg hatching.
Analysis of the production of all homozygous lines of rainbow trout by gynogenesis
Authors: Quillet Edwige , Garcia Pascale , Guyomard R.
Published: June 2005

Homozygous gynogenetic (GE) rainbow trout (Oncorhynchus mykiss) were produced, using diploid gynogenesis with UV rays as an agent of sperm inactivation and heat shock as treatment for inhibition of first cleavage and restoration of diploid status. Their survival and growth performances were analysed in progenies from individual females, and compared with both diploid outbred control (D) and gynogenetics resulting from inhibition of meiosis II (GP).

The homozygous status of GE fry was proved by electrophoretic control.

Mean survival of GE groups was quite low (around 19% of D control at feeding start, vs. 63% in GP) but much depended on the founder female. A positive correlation was found between early survival of haploids and late survival of diploid GE fry from the same mother.

Growth was also very reduced in both gynogenetics, though to a lesser extent (90 and 80% of D control at day 103 in GP and GE groups respectively).
Molluscan shell matrix phosphoproteins: Correlation of degree of phosphorylation to shell mineral microstructure and to in vitro regulation of mineralization
Authors: Borbas Jill E. , Wheeler A. P. , Sikes C. Steven
Published: June 2005

The potential role of phosphoproteins in the regulation of carbonate biomineralization is examined by comparing the EDTA‐soluble matrix (SM) of bivalve shells from representatives of eight superfamilies having various aragonitic and calcitic microstructures. In each case the SM is separated into two fractions by gel permeation chromatography. The lower molecular weight fractions (Mr range 15,000–500,000) were assayed for protein and phosphate content, and their ability to regulate calcitic CaCo3 formation was determined from their performance as inhibitors in a pH‐stat crystal growth assay. The SM fraction from two species with foliated calcitic shells is 12.9–15.7% phosphate by weight while SM fractions isolated from shells or shell layers of six species with calcitic prismatic or various aragonitic microstructures all contain significantly lower phosphate levels (0–3.3% by weight). The more highly phosphorylated SM fractions are significantly better inhibitors of calcitic crystal growth, requiring approximately 30% of the concentration on a weight basis as the low phosphate fractions to effect a 50% reduction in growth rate. Enzymatic dephosphorylation of the high phosphate SM fractions results in reduced inhibition capabilities that are approximately equal to those of the low phosphate SM fractions. Finally, neither dephosphorylated nor naturally low phosphate SM fractions were as effective as phosphorylated foliated matrix in maintaining inhibition in the pH‐stat assay as crystals continue to grow. In conclusion, it appears that degree of SM phosphorylation in part may be a factor in the regulation of carbonate crystal growth in vivo and thus explain its variability among the various shell microstructures.
Differential growth of male and female urinogenital systems of Caretta caretta, within the sex‐determining period
Authors: Harry Jenny L. , Williams Keith L.
Published: June 2005

The sex of loggerhead turtle embryos is determined by incubation temperature. We are interested in identifying temperature‐dependent events during the development of the urinogenital system to more clearly define the “window” where sex is determined. Consequently, we have closely monitored the stages of whole embryo development in conjunction with the development of the urinogenital system. While an increase in constant incubation temperature shortens the length of the incubation period for Caretta caretta, the wet weight of whole embryos (set at the male‐ (26°), pivotal‐ (28°C), and female‐ (32°C) determining temperatures) is very similar at each developmental stage. However, different growth patterns for the male and female urinogenital systems are found during the sex‐determining period (stages 22–27) of embryognesis. Thus, within this critical period, incubation temperature has a particular influence on the growth of urinogenital tissue.
Highly specialized sperm surface antigens in the Nile tilapia, Oreochromis niloticus, as revealed by conventional antisperm antibody and autoantibody
Authors: Lou Y.‐H. , Takahashi H.
Published: June 2005

Conventional antibodies and autoantibodies against spermatozoa of the Nile tilapia, Oreochromis niloticus, were used to study sperm surface antigens of the fish. Absorption assays using a variety of tilapia tissues demonstrated that antigens reacting to conventional antitilapia sperm (ATS) antibodies were highly specific to spermatozoa. By immunoblotting analyses of isolated plasma membrane of tilapia spermatozoa, at least 15 kinds of constituent proteins were recognized by ATS antibodies as surface antigens, among which six were identified as autoantigens by autoantibodies purified from male fish immunized with allogeneic spermatozoa. Immunohistochemistry of testis sections revealed that most of the antigens began to emerge on spermatids by the final stage of spermiogenesis. Immunofluorescent analysis of sperm smear, either using ATS antibodies or autoantibodies, showed that the antigens were mainly distributed on the surface of the sperm head and midpiece. The stage at which sperm‐specific antigens came to appear was discussed in relation to the stage for the formation of blood‐testis barrier in the tilapia.
Involvement of juvenile hormone in the induction of antifreeze protein production by the fat body of larvae of the beetle Dendroides canadensis
Authors: Xu Lei , Duman John G.
Published: June 2005

Larvae of the Pyrochroid beetle Dendroides canadensis produce hemolymph antifreeze proteins (AFPs) as an adaptation to subzero overwintering temperatures. The AFPs are produced in early autumn in response to various environmental cues (short photoperiod, low temperature, short thermoperiod). The study presented here reinforces and extends the initial finding (Horwath and Duman, '83b) that juvenile hormone is involved in stimulating production of AFPs. Dose response curves showed seasonal variation in the sensitivity of the larvae to topical application of Juvenile Hormone (JH), with late summer larvae being more sensitive than early summer ones. The time response curve for induction of AFP activity in late summer larvae demonstrated that ∼14 days are required after JH treatment for the appearance of a significant increase in AFP activity. The timing of this response to JH induction is similar to that seen previously when larvae were acclimated to a short photoperiod.

Studies with cultured fat bodies showed that the fat body is a probable site of production of the AFP, and further emphasized a role for JH in AFP induction. However, stimulation of AFP production by fat body only occurred when the fat bodies were removed from larvae that had been pretreated with JH. The presence of JH in the culture medium did not stimulate fat bodies taken from larvae that had not been pre‐treated. This suggests that an additional hormone(s), or other factor, may be required to induce fat body production of AFPs.
Involvement of cyclic nucleotides in light‐induced resumption of development of Artemia embryos
Authors: Van Der Linden A. , Gadeyne J. , Van Onckelen H. , Van Laere A. , Decleir W.
Published: June 2005

The resumption of development upon light activation of Artemia embryos is accompanied by an immediate drop in cyclic adenosine monophosphate (cAMP) concentration. The concentration of cyclic guanosine monophosphate (cGMP) remains unaltered, however. A similar effect is observed when the cysts are treated with H2O2, with which we demonstrated that its action mimics light activation. The demonstrated decrease in cAMP is the earliest observed intracellular event after light induction. Possible regulatory roles of cyclic nucleotides in light‐induced resumption of development are discussed.
Developmental interactions in the pigmentary system of the tip of the mouse tail: Effects of coat‐color genes on the expression of a tail‐spotting gene
Authors: Hirobe Tomohisa
Published: June 2005

The tails of agouti C3H/HeJmsHir mice are completely pigmented, whereas the tails of black C57BL/10JHir animals possess unpigmented tips. Genetic analysis indicates that white tail‐tipping is due to an autosomal recessive gene, with incomplete penetrance, that segregates independently from the gene for agouti with a maternal influence in the F1 generation. To analyze the influence of specific coat‐color genes on the expression of tail‐spotting in mice, five congenic lines of C57BL/10JHir with different coat colors were prepared. No influence was observed on the occurrence of tail‐spotting in agouti (A/A) or dilute (d/d) mice or in F1 mice from crosses between black and albino (c/c), or in F1 mice from crosses between black and pink‐eyed dilution (p/p). However, the frequency of tail‐spotting was dramatically decreased in brown (b/b) mice. These results suggest that the mutant allele (b) at the brown locus is involved in determining the extent of pigmented areas in the tail tips of mice through an interaction with the tail‐spotting gene.
Sensitivity of hemoglobins to intracellular effectors: Primitive and derived features
Authors: Scholnick David A. , Mangum Charlotte P.
Published: June 2005

The sensitivity of hemoglobin‐O2 binding to urea and Cl−, effectors in higher vertebrates and also blood constituents that vary with salinity in elasmobranchs, was examined in the highly euryhaline cownose ray Rhinoptera bonasus. The response was compared with that in a closely related stenohaline species, as well as several other elasmobranchs, teleosts, and simpler hemoglobin‐containing animals. Although the O2 binding of R. bonasus red blood cells and stripped hemoglobin is not sensitive to urea, trimethylamine oxide, or Cl−, neither is the hemoglobin of the stenohaline butterfly ray. Cl− lowers O2 affinity of the hemoglobins of three species of stenohaline sharks; urea only slightly increases O2 affinity of one of these hemoglobins and another is insensitive. In contrast, the hemoglobins of two highly euryhaline teleosts are sensitive to urea as well as Cl−; urea raises and Cl− lowers O2 affinity. Thus, while urea insensitivity does appear to protect the respiratory properties of the O2 carrier in the elasmobranchs, Cl− sensitivity appears to be unrelated to changes in the blood. Since the red blood cells and/or hemoglobins of simpler animals such as annelids and molluscs are also insensitive to urea and Cl−, insensitivity in the elasmobranchs is more likely to represent a primitive, inherited feature than one specifically evolved along with their distinctive form of osmoregulation.

The limited information available suggests that ATP lowers O2 affinity of the shark but not ray hemoglobins, which may reflect the origin of intracellular modulation within the elasmobranchs.
Proportioning of body regions in the planarian Dugesia tigrina as a function of the length: Width ratio of the regenerating fragment
Authors: Mead Robert W.
Published: June 2005

Regeneration was examined in different regions of planaria (Dugesia tigrina) in order to determine the effect that the shape of a section exerts on proportion regulation during regeneration. Length: width ratios were used as an index of section shape and experiments utilized sections at which this ratio was below 1.0 Proportion regulation was evaluated by determining relative area of major body regions for normal and abnormal regenerates. Proportional area of body regions anterior to the pharynx increased with proportional decreases in the length: width ratio for all regenerates, but this increase was greater for regenerates that originated from segments anterior to the pharynx. Changes in proportional area of one anterior body region were closely correlated to changes in porportional area of other anterior body regions. The exact nature of these correlations varied as a function of originating segment. A hierarchy also exists in proportional head tissue between normal and abnormal regenerates as total relative head area of twoheaded regenerates was around three times that of normal planarians while regenerates with one large head and without a pharynx had a proportional head size that was less than that of two‐headed animals but more than twice that of normal planarians.
Toward an understanding of the epithelial requirement for osteogenesis in scleral mesenchyme of the embryonic chick
Authors: Pinto Cheryl B. , Hall Brian K.
Published: June 2005

Explants of scleral tissue from chick embryos of H.H. stage 29–36 (6–10 days of incubation) were used to determine if the epithelial‐mesenchymal interaction which initiates scleral bone formation is cell contact, extracellular matrix, or diffusion mediated. Transfilter tissue recombinations, in which explanted interacting tissues are associated across interposing Nuclepore filters of various pore sizes and thicknesses, were performed with scleral mesenchyme and epithelium. When filters with pore sizes which would allow the passage of cell processes and diffusible substances were used, osteogenesis was initiated in the scleral mesenchyme. When cell processes were blocked with thicker filters or smaller pore sizes, bone formation still occurred, indicating that a diffusible substance mediates this tissue interaction. Further support for a diffusion‐mediated interaction came from transfilter experiments using dialysis membranes to discriminate the size of the molecule(s), and Millipore filters to determine the distance over which these molecules travel. These experiments revealed that the scleral epithelial diffusible factor has a molecular weight of between 3500 and 6000 daltons, and acts over distances between 150 and 300 μm.
Uniform myosin isoforms in the flight muscles of little brown bats, Myotis lucifugus
Authors: Hermanson John W. , LaFramboise William A. , Daood Monica J.
Published: June 2005

The present study used muscle histochemistry and polyacrylamide gel electrophoresis of native myosin and myosin heavy chains to establish a correlation, if any, between chiropteran histochemical fiber types and myosin isoform composition. Histochemical analysis of the primary flight muscle, the pectoralis profundus, documented the presence of a single histochemical fiber type, here termed Type II. Electrophoresis of native myosin isolated from pectoralis muscle yielded a single isoform that comigrated with the FM‐3 isoform of rat diaphragm. Heavy chain analysis of the Myotis pectoralis demonstrated a single heavy chain with comparable electrophoretic mobility to rat IIa myosin heavy chain. These data demonstrate unique histochemical and biochemicla homogeneity in the myosin composition of the pectoralis muscle of Myotis lucifugus. Thus this muscle is extremely specialized for flight at histochemical, morphologic, and molecular levels. These data contrast with the mixed myosin and histochemical fiber types found in other mammals, as well as in other muscles of Myotis lucifugus.
Monoclonal antibody specific to signet ring cells, the vanadocytes of the tunicate, Ascidia sydneiensis samea
Authors: Uyama Taro , Nishikata Takahito , Satoh Noriyuki , Michibata Hitoshi
Published: June 2005

Ascidians are known to accumulate vanadium in their blood cells and have six to nine different types of blood cells. Among these cells, the signet ring cell has been newly identified as the vanadocyte (vanadium‐containing blood cell). We have raised monoclonal antibodies specific to the signet ring cells of Ascidia sydneiensis samea for use in the identification of vanadocytes. A hybridoma cell line which secretes a monoclonal antibody specific to the signet ring cell has been established. Immunoblotting analysis showed that the antigen recognized by the antibody is a single polyptide of about 45 kDa. It appears that the monoclonal antibodies specific to the signet ring cells may be useful markers for studies for the process of differentiation of ascidian blood cells.
Testicular thymidine incorporation in the prawn Macrobrachium rosenbergii: Molt cycle variation and ecdysteroid effects in vitro
Authors: Sagi Amir , Karp Lee , Milner Yoram , Cohen Dan , Kuris Armand M. , Chang Ernest S.
Published: June 2005

While molting and reproduction in female crustaceans are often known to be coupled processes, the explicit nature of this coupling has not been studied in males. We examined the relationship between molting and spermatogenesis in 2 morphotypes of the freshwater prawn, Macrobrachium rosenbergii. These morphotypes were the rarely molting, dominant, blue‐claw male and the frequently molting, subdominant, orange‐claw male. Testes from the 2 morphotypes were dissected and cultured in vitro. The rate of [3H]‐thymidine incorporation (as a measure of DNA synthesis) was recorded. Autoradiography was performed with histological sections of the cultured tissue.

A strong correlation between the incorporation rate and the molt stage was found. The blue‐claw males were intermolt stage C4 and the testicular [3H]‐thymidine incorporation rate was relatively low. The incorporation rate in premolt orange‐claw males was at least three times higher than in these results: heavy silver grain precipitation was observed on top of the spermatogenic zone in the testicular sections taken from premolt orange‐claw males.

The correlation between DNA synthesis in the testes and the molt stage suggested that ecdysteroids either directly or indirectly participate in the regulation of spermatogenesis. We observed that 20‐hydroxyecdysone did indeed have a direct effect on DNA synthesis in cultured testis. Addition of 2.6 × 10−6M 20‐hydroxyecdysone increased [3H]‐thymidine incorporation into testes of premolt prawn by more than 50%.
Induction of deer antlers by transplanted periosteum: III. Orientation
Authors: Goss Richard J.
Published: June 2005

The effects of rotating, inverting, or mincing grafts of presumptive pedicle/antler periostea have been investigated in young male fallow deer. When discs of frontal periosteum were rotated 180° and replaced onto their pedicle regions, half of the resultant antlers grew in reversed orientation, while the others gave rise to appendages of indeterminate polarity. Transplantation of periosteal discs upside down beneath scalp or foreleg skin induced antlers of normal proximodistal orientation. Grafts inverted on top of intact pedicle protuberances with their anterior‐posterior and medial‐lateral axes in register produced antlers of normal lengths but with more points than in controls. If the antlerogenic periosteum is minced and scrambled before transplantation back onto the pedicle region, it is capable of producing an organized antler. It is concluded that the histogenesis of pedicle and antler resides in the frontal periosteum, and that the anterior‐posterior axis of antler orientation is determined by this tissue. The proximodistal axis of elongation is established in relation to the overlying skin. Other morphogenetic influences as yet to be identified contribute to the normalization of antler size and shape in the prospective sites of antlerogenesis on the head.
Egg capsule sheath of Loligo opalescens Berry: Structure and association with bacteria
Authors: Biggs James , Epel David
Published: June 2005

The sheath forming the outer layer of the egg capsule of the squid Loligo opalescens is an acellular matrix 1–2 mm thick which contains approximately 100 striations parallel to the capsule surface. Throughout this matrix is suspended a dense culture of bacteria arranged in one to five layers. The probable source of these bacteria is the accessory nidamental gland.
The role of the legs in the lateral giant fibre escape of the crayfish Cherax destructor (Crustacea: Decapoda: Astacura)
Authors: Davey Natalie , Macmillan David L.
Published: June 2005

It is known that leg positioning is important for reducing drag during escape mediated by the medial giant (MG) axon of the crayfish (Cooke and Macmillian, '85). This report examines the question of whether the legs also have a role in escape mediated by the lateral giant (LG) neuron. The trajectory and the dynamics of the lateral giant (LG) escape behaviour of the crayfish Cherax destructor were analyzed using high speed cinematographic techniques. The LG escape flip was found to be stereotyped for each particular animal but rested animals produce their own characteristic trajectories. We tested to see if denervation of the legs would alter the escape trajectory. Interference with the articulating membrane at the base of the legs alters escape performance and a new set of displacement curves characteristic of each animal is produced. This is the outcome whether or not the nerves are severed. Electrophysiological recordings confirmed earlier latency measurements (Cooke, '85) and indicate that the efferent signals to the legs evoked by LG activation arrive too late to position them to influence the escape trajectory. We suggest that operations on the articulating membrane produce their effects by altering the starting position of the legs. We provide some preliminary evidence that supports this hypothesis.
Branchial and branchiostegite carbonic anhydrase in decapod crustaceans: The aquatic to terrestrial transition
Authors: Henry Raymond P.
Published: June 2005

Carbonic anhydrase (CA) activity was measured in the gills, branchiostegite, and cuticle of 5 species of decapod crustaceans displaying fully aquatic, semi‐terrestrial, and fully terrestrial lifestyles. Density‐gradient and differential ultracentrifugation were used to separate 2 subcellular fractions from these tissues, basal‐lateral membranes, and cytoplasm, in which CA activity was determined. Callinectes sapidus, a euryhaline aquatic species, had high levels of CA activity in both the cytoplasmic and membrane fractions of the gills. These pools of CA are believed to function in ion transport and CO2 excretion, respectively. The branchiostegite and cuticle, which do not play an apparent role in either process in the blue crab, possess much lower levels of CA activity in both fractions. In contrast, a stenohaline, stenothermal species, Chaceon fenneri, which has a low metabolic rate, has low levels of CA activity in the cytoplasm and membrane fractions of the gills. As decapod crustaceans invade the terrestrial habitat and make the transition to breathing air, gill surface area is reduced and the branchiostegite develops into a primitive lung. In Cardisoma guanhumi, a semi‐terrestrial crab, branchiostegal tissue has very little CA activity in either fraction, and enzyme activity is not different from that in the general cuticle; the gills still possess the bulk of CA activity in the animal. In fully terrestrial species (Gecarcinus lateralis and Birgus latro), however, the membrane fraction of the branchiostegite has the same level of CA activity as that of the gills, regardless of species, while CA in the cuticle remains low. It appears, according to the distribution of membrane‐associated CA, that while the gills of aquatic crustaceans are the primary route of CO2 excretion, the branchiostegite can supplement branchial CO2 elimination in terrestrial species.
Daily variations in plasma hormone concentrations during the semilunar spawning cycle of the gulf killifish, Fundulus grandis
Authors: Emata Arnil C. , Meier Albert H. , Hsiao Shyh‐Min
Published: June 2005

Male and female gulf killifish, Fundulus grandis, were kept in large cages submerged in their natural habitat in the Gulf of Mexico. Gonadosomatic indices (GSI: 100 × gonad weight/body weight) and blood samples were obtained from male and female fish every 4 hours (beginning at 1600) throughout a day on 3 separate days of the semilunar cycle: at the GSI and spawning peak (July 27–28), at midcycle (August 2–3), and on a day prior to the probable spawning peak (August 9–10). Blood samples of females were assayed for cortisol, estradiol‐17β (E2), progesterone, testosterone, thyroxine (T4), and triiodothyronine (T3). The daily rhythms of hormones at each of the three days during the cycle differed markedly from one another. At the spawning peak, E2 and T3 peaks occurred at 1200, testosterone and progesterone peaks were found at 2400 and the GSI and cortisol peaks were at 0400. The GSI decreased sharply at 0800 indicating a period of probable spawning. At midcycle, most hormone levels were low throughout the day and the amplitudes of the hormone rhythms were suppressed. One day prior to the spawning peak, testosterone and progesterone variations (peaks at 2400) were similiar to those found on the day of the first semilunar GSI and spawning peaks. Daily variations of other hormones, especially E2, were prominent on the day prior to peak spawning but different from those found on the day of peak GSI/spawning. In males, plasma concentrations of cortisol, testosterone, T3 and T4 also underwent daily variations that differed from one another on the 3 days of the cycle. The results clearly demonstrate that there are dramatic changes in the daily variations of plasma hormone concentrations during the semilunar spwning cycle.