bluuebunny/crossref_metadata_2025_split huggingface dataset:
Accessibility of the insect nervous system to a neurotoxic polypeptide
Authors: Fishman Lena , Kagan Michael L. , Zlotkin Eliahu 
Published: June 2005

AbstractThe 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

AbstractOvarian 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

AbstractIn 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

AbstractThe 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

AbstractFilling 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

AbstractWe 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

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractHomozygous 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

AbstractThe 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

AbstractThe 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

AbstractConventional 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

AbstractLarvae 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

AbstractThe 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

AbstractThe 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.