bluuebunny/crossref_metadata_2025 huggingface dataset:
Stage‐specific response of preimplantation mouse embryos to W‐7, a calmodulin antagonist
Authors: Yamamura Hideki , Spindle Akiko
Published: June 2005

Involvement of calmodulin‐dependent processes in preimplantation development of mouse embryos was studied with the use of N‐(6‐aminohexyl)‐5‐chloro‐1‐naohthalenesulfonamide (W‐7), a specific antagonist of calmodulin. At 25 μM, W‐7 interfered with compaction of eight‐cell embryos, caused decompaction of compacted eight‐cell embryos, inhibited cavitation of late morulae, and caused collapse and degeneration of blastocysts. These effects of W‐7 appear to be due to specific inhibition of calmodulin‐dependent processes, because W‐5, a less active analogue of W‐7, was less effective in interfering with development; at 25 μM, W‐5 had only a slight effect on compaction and had no effect on blastocyst formation, maintenance of blastocoels, or post‐blastocyst development. In addition to the developmental effects just described, W‐7 inhibited cell proliferation in four‐cell embryos and reduced cell numbers of morulae after treatment at the two‐ to eight‐cell stages. There was a marked increase in embryos' sensitivity to W‐7 at the late morula stage, and the sensitivity increased further as embryos developed into blastocysts; the effects of W‐7 were largely reversible after treatment at the two‐cell through the compacted eight‐cell stages, but not after treatment at the late morula or blastocyst stage. At the blastocyst stage, inner cell mass cells appeared to be slightly more resistant to W‐7 than trophectoderm cells. This differential sensitivity became more pronounced at the late blastocyst stage: after 3.5–4‐h exposure of late blastocysts to 25 μM W‐7, all trophectoderm cells degenerated but most of the inner cell masses survived. From these results it appears that calmodulin‐dependent processes are involved in development of mouse embryos at all of the preimplantation stages examined.
Infertility in transgenic female mice with human growth hormone expression: Evidence for luteal failure
Authors: Bartke A. , Steger R. W. , Hodges S. L. , Parkening T. A. , Collins T. J. , Yun J. S. , Wagner T. E.
Published: June 2005

Introduction of the human growth hormone (hGH) gene fused with mouse metallothionein I promoter into domestic mice leads to ectopic synthesis of hGH, marked stimulation of somatic growth, and female sterility. Transgenic females (produced by mating transgenic males to normal females) mated but failed to become pregnant or pseudopregnant as evidenced by the recurrence of vaginal plugs every 5–7 days. Daily injections of 1 mg progesterone, starting on day 1 postcoitum (p.c.), maintained pregnancy, suggesting that the sterility of these animals is due to inadequate luteal function. In ovariectomized female transgenic mice, median eminence (ME) turnover of dopamine (DA) was increased, and plasma prolactin (PRL) levels were reduced, presumably because of the known lactogenic activity of hGH in rodents. From these observations we suspected that either (1) the corpora lutea of these animals are unresponsive to lactogenic hormones, or (2) hGH by stimulating tuberoinfundibular dopaminergic (TIDA) neurons interferes with the increase in PRL release that normally follows mating and this, in turn, leads to luteal failure. To distinguish between these possibilities, transgenic females were treated with PRL‐secreting ectopic pituitary transplants from normal females of the same strain on day 1 p.c. Eight of ten treated females became pregnant and delivered litters. We conclude that infertility of transgenic female mice with hGH expression is due to activation of the TIDA system, suppression of endogenous PRL release, and luteal deficiency.
Influence of postovulatory aging on chromosome segregation during the second meiotic division in mouse oocytes: A parthenogenetic analysis
Authors: O'Neill G. T. , Kaufman M. H.
Published: June 2005

A high incidence of parthenogenetic activation was observed when postovulatory aged mouse oocytes were exposed briefly to hyaluronidase in culture medium at 18–26 h after the human chorionic gonadotropin injection for inducing superovulation. The majority of the activated oocytes extruded a second polar body and developed a single haploid pronucleus. Cytogenetic analysis of this class of parthenogenone at metaphase of the first‐cleavage mitosis has clearly demonstrated that the completion of the second meiotic division in activated aged oocytes is not associated with a significant increase in the incidence of chromosome segregation errors. The increasing postovulatory age of oocytes prior to activation was observed to significantly decrease the capacity of activated oocytes to extrude the second polar body.
Localization of ecdysteroids in the eyestalk ganglia of the fiddler crab, Uca pugilator, during anecdysis and proecdysis
Authors: Hopkins Penny M.
Published: June 2005

Ecdysteroids have been found in eyestalk tissues of the fiddler crab, Uca pugilator. Throughout the molt cycle, ecdysteroids are present in much higher concentrations in the eyestalk tissues than can be accounted for by equilibrium diffusion from the hemolymph. The greatest eyestalk‐to‐hemolymph ratio is found during anecdysis, the nonmolting period when the highest levels of the molt‐inhibiting hormone are being produced and released from the eyestalks. RIA‐active ecdysteroids are localized primarily (but not exclusively) in the medulla terminalis (MT) and medulla interna (MI) portions of the eyestalk ganglia. Relative levels of ecdysteroids extracted from the MT and MI fluctuate during the molt cycle. Ecdysone was the predominant ecdysteroid present in the eyestalks. Histological examination of eyestalks revealed two areas of cell bodies in the MT and medulla externa (ME) that release colloidlike substances into the intraganglionic cortical glial spaces. The location of the MT cell bodies corresponds to the pars distalis‐X‐organ of other crustaceans, but no organ of Bellonci (which has been proposed as a source of ecdysteroidlike compounds in shrimp) was found.
Selectivity of protein sequestration by vitellogenic oocytes of the rainbow trout, Salmo gairdneri
Authors: Tyler Charles R. , Sumpter John P. , Bromage Niall R.
Published: June 2005

The selectivity of protein sequestration by vitellogenic oocytes of the rainbow trout, Salmo gairdneri, was investigated by comparing the rates of uptake of radiolabelled vitellogenin (VTG) and bovine serum albumin (BSA). Fish were injected simultaneously with equal amounts of both 3H‐VTG and 14C‐BSA and sampled subsequently at varying time invervals to assess the rates of uptake of these proteins into the developing oocytes. Both labelled proteins were taken up rapidly into the blood after their injection into the peritoneal cavity. Once in the blood, they became available for sequestration by the vitellogenic oocytes. There was both rapid and selective uptake of 3H‐VTG; within 72 hours half of the 3H‐VTG injected was present within the ovary, whereas only 2.5% of the 14C‐BSA was similarly located. Once within the oocyte, 3H‐VTG was specifically and rapidly processed to yield its constituent yolk proteins, which included 3H‐lipovitellin. In contrast, after 72 hours 14C‐BSA was present in the oocyte as the native, intact protein. However, after 13 days, whereas the yolk proteins had undergone no further processing, remaining stable within the oocyte, much of the BSA within the ovary had been degraded to an array of smaller peptides. Furthermore, after 26 days, whereas all of the 3H‐VTG endocytosed remained within the oocytes as yolk protein, at least half of the BSA taken up initially had been exocytosed. Calculation suggested that 3H‐VTG was sequestered about 60 times more rapidly than 14C‐BSA. Other tissue did not incorporate 3H‐VTG to any significant degree. These results suggest that VTG was sequestered into vitellogenic oocytes by receptor‐mediated endocytosis, whereas BSA, along with other extraneous proteins, was taken up adventitiously.
Caffeine promotes in vitro fertilization of mouse ova within 15 minutes
Authors: Pomeroy K. O. , Dodds J. F. , Seidel G. E.
Published: June 2005

Epididymal sperm were collected from C57B16/J × DBA2/J (B6D2) males and allowed to capacitate for 2 hr. When cumulus‐fre oocytes were exposed to sperm for 15 min in either the presence (6.0 mM) or absence of caffeine, fertilization did not occur. However, when cumulus cells were left intact, 23% of oocytes were fertilized in caffeine‐free medium and 62% in caffeine‐containing medium. When cumulus‐free oocytes were incubated with sperm for 30 min, none was fertilized in the absence of caffeine, but 33% were fertilized when 6.0 mM caffeine was present (P < .02). These effects of caffeine were on the sperm, as sperm exposed to caffeine and then coincubated with oocytes for 15 min in essentially caffeine‐free media fertilized a similar percent of oocytes (93%) as when sperm and oocytes were exposed to caffeine during the fertilization period (86%). When sperm were capacitated in caffeine‐containing medium, the percentage of ova fertilized was similar to capacitation without caffeine. We conclude that both cumulus cells and caffeine speed up the fertilization process with mouse gametes and that the effect of caffeine is on the sperm, but not due to more rapid capacitation.
Recent applications of fish cell culture to biomedical research
Authors: Hightower Lawrence E. , Renfro J. Larry
Published: June 2005

Tissues of the fishes are as amenable to the techniques of modern cell culture as mammalian tissues and organs, and yet this vast resource, comprising thousands of vertebrate species, remains largely unexplored. The model systems that have been developed demonstrate the utility of fish cells as sources of special adaptations and exaggerated physiological systems. In this review, we briefly describe several of the successful models along with recent developments in fish cell culture with the hope of stimulating increased interest in the lower vertebrates as useful complements to mammalian cell culture in biomedical research. The topics covered include epithelial ion transport, endocrinological studies, the cellular stress (heat shock) response, thermotolerance, cancer biology, and environmental toxicology.
The occurrence of elongated intercellular bridges in deep cells of Oryzias embryos during blastula and gastrula stages
Authors: Kageyama Tetsuo
Published: June 2005

The occurrence of an elongated intercellular bridge (IB) connecting a pair of post‐mitotic cells in the middle of which a midbody intervenes has been reported in several lines of cultured cells and on the surface of embryonic epithelia. Using the cell isolation method, this same structure also was revealed to be present in inner blastomeres of the embryo of Oryzias latipes. The IB emerges in the midblastula stage, when cleavage has become asynchronous and deep cells with protruding pseudopodia begin their locomotion through expanding intercellular space. The paired cells interconnected by the IB occupy 7–10% of the total number of deep cells, and some IBs are elongated to as long as 50 μm from the midblastula until the beginning gastrula stage. The IB is produced by incomplete cytokinesis, and it probably elongates itself until it is approximately 5 μm in length. Several lines of evidence suggest that the IB elongates further as sister cells move apart by means of pseudopodia. The fraction of elongated IBs gradually decreases during the gastrula stage, until no IB is observed thereafter. One likely cause of the decrease is that the gastrula has less space for divided cells to separate from each other, preventing the IB from elongating further. Naturally, the maximal and average lengths of the IB decrease as the gastrula stage proceeds.
Cytology, embryology, and evolution of the developmental arrest syndrome in newts of the genus Triturus (Caudata: Salamandridae)
Authors: Sessions Stanley K. , Macgregor Herbert C. , Schmid Michael , Haaf Thomas
Published: June 2005

We have examined embryonic development in three species (T. carnifex, T. cristatus, and T. marmoratus) of European newts of the genus Triturus (subgenus Neotriton) in which developmental arrest occurs in embryos that are homomorphic for a chromosomal heteromorphism involving chromosome 1 (Horner and Macgregor: J. Herpetol., 19:261–270, 1985). Embryonic arrest occurred during tailbud stages in all three species, but at a slightly earlier stage in T. marmoratus. Two phenotypes were identified among the arrested embryos. One of these is indistinguishable in embryonic morphology from normal embryos at all stages up to the time of arrest, but the other is characterized by a protruding yolk plug, which persists from the late gastrula/early neurula stage to the tailbud arrest stage and apparently interferes with normal morphogenesis. Evidence is presented that the two arrested phenotypes, which occur in approximately equal numbers, represent embryos that carry the two alternative homomorphic chromosome pairs of chromosome 1 heteromorphism. We conclude that developmental arrest reflects a balanced lethal heterozygosity probably resulting from an unequal exchange of genic material between the homologues of chromosome 1 which occured in a common ancestor of the Neotriton species.
Maintenance of foreign gene expression and independent chromosome fragments in adult transgenic rainbow trout and their offspring
Authors: Disney Jane E. , Johnson Kenneth R. , Banks Deanna K. , Thorgaard Gary H.
Published: June 2005

Transgenic rainbow trout (RT) were generated in earlier experiments by an in vivo modification of the chromosome‐mediated gene transfer technique. This involved fertilizing albino RT eggs with gamma‐irradiated brook (speckled) trout (ST) sperm and then heat shocking the eggs to induce second polar body retention. Striped pigment patterns were stable in six mosaic individuals between the ages of 7 and 14 months. We estimated the total ST DNA contribution in adult transgenic fish using DNA dot blot analyses. An average of 7% ST DNA was obtained in analyses of 11 transgenic individuals. Nine of 55 transgenic individuals examined expressed a ST‐specific isozyme in adulthood; some were mosaic for foreign gene expression. Variable numbers of autonomous chromosome fragments were maintained in 10 adult transgenic individuals examined. Five transgenic RT were backcrossed to albino RT. Chromosome fragments were inherited by 29 of 31 backcross embryos examined. Additional active nucleolar organizer regions (NORs) were present on some fragments and may also have been integrated into some host chromosomes. This method may have numerous applications for basic and applied genetic research in fish.
Experimental induction of claw transformation in snapping shrimps
Authors: Govind C. K. , Wong Anna , Pearce Joanne
Published: June 2005

The effectiveness of various manipulations of the major claw in inducing the contralateral minor claw to transform into a major claw in adult snapping shrimps, Alpheus heterochelis, was studied. While removal of the major claw was 100% effective in inducing transformation, sectioning of its nerve was effective in about two‐thirds of the animals, and tenotomy of its closer muscle was effective in less than one‐half. Occasionally, tenotomy of the opener muscle induced transformation, whereas immobilizing the claw was totally ineffective. This gradation in effectiveness, which is related to the degree of trauma applied to the major claw, suggests a central mechanism regulating bilateral asymmetry of the claws.
Do amiloride and ouabain affect ammonia fluxes in perfused Carcinus gill epithelia?
Authors: Lucu Čedomil , Devescovi Massimo , Siebers Dietrich
Published: June 2005

The effects of inhibitors on the efflux of ammonia (from the basolateral to the apical side, Jb→a) were studied in preparation of isolated Carcinus gills immersed in dilute seawater (DSW) that was identical to the perfusion solution. Adding 10−4M amiloride to the solution bathing the gill preparations reduces the efflux of ammonia by 29% relative to the control value. Under experimental conditions, it appears that only about 1% of the amiloride‐sensitive influx of Na+ (Ja→b) can be exchanged with NH on an equimolar basis.

The ammonium ion is apparently transported at the basolateral side by a carrier‐mediated process. Kinetic analyses of the influx of ammonium ions revealed a Km of 36.99 μM and a maximum velocity (Vmax) equal to 19.6 μmol g−1 h−1.

Basolaterally applied ouabain (5 × 10−3M) and NaCN (10−3M) reduced the efflux of ammonia by 46.7 and 42.2%, respectively, suggesting an interaction of NH with the basolaterally located Na+/K+ exchanger in which NH appears to be able to substitute for K+.
Selective identification of the paternal mitochondrion in living sea urchin eggs and embryos by chlorotetracycline
Authors: Hinkley Robert E. , Newman Arthur N.
Published: June 2005

When sea urchin eggs are pretreated with fluorescent chelate probe chlorotetracycline (CTC) and then fertilized with unlabeled sperm, a small, brightly fluorescent particle resembling the mitochondrion of free‐swimming sperm both in size and fluorescent staining characteristics appears in the egg cytoplasm. This particle first appears near the base of the insemination cone and, like the paternal mitochondrion identified in previous ultrastructural studies, remains closely associated with the male pronucleus during its microtubule‐dependent migration toward the egg center. These similarities strongly suggest that the fluorescent particle observed in the cytoplasm of living, CTC‐pretreated sea urchin eggs is, in fact, the mitochondrion of the fertilizing sperm.
Seasonal variation in freeze tolerance and ice content of the tree frog Hyla versicolor
Authors: Layne Jack R. , Lee Richard E.
Published: June 2005

Freeze tolerance and ice content of Hyla versicolor showed pronounced variation between summer (June) and winter (December). Summer frogs survived freezing at −3°C for up to 9 hr and ice accumulation up to 50% of their total body water. A time course of ice formation indicated that an equilibrium level was reached in approximately 15 hr. Thus, the lethal ice content was less than the equilibrium ice content for these conditions (63.1%). A second group was induced to enter an overwintering condition by holding them through the summer and then subjecting them to a progressive reduction in temperature and photoperiod for 2 months. These frogs survived freezing for 48 hr at −3°C. Their equilibrium ice content at this temperature was significantly lower (52.5%) than comparably treated summer animals. In the winter acclimatized group, frozen frogs had substantially higher blood glucose levels than unfrozen frogs (22.7 μmol/ml vs. 1.33 μmol/ml), but glycerol levels were not elevated after freezing. Freezing frogs conditioned for overwintering at −7°C resulted in a higher equilibrium ice content (62.6%), but none survived. It is evident that in preparation for overwintering, frogs reduce the amount of ice formed at a given subzero temperature, but there is little indication of a substantial change in the total amount of ice tolerated.
Plasma arginine vasotocin, angiotensin II, and salt gland function in freshwater‐ and seawater‐adapted kelp gulls (Larus dominicanus)
Authors: Gray David A. , Erasmus Theunis
Published: June 2005

Kelp gulls (mean body weight of 905.3 ± 46.5 g, plasma osmolality of 316.5 ± 1.5 mOsm.kg−1, plasma Na+ of 151.3 ± 0.8 mEq.liter−1, and plasma K+ of 3.1 ± 0.2 mEq.liter−1 (means ± SE) were adapted to fresh water and had basal plasma concentrations of arginine vasotocin (AVT) and angiotensin II (AII) of 13.6 ± 1.1 pg.ml−1 and 48.1 ± 3.4 pg.ml−1, respectively. Adaptation to seawater strengths of 25, 50, 75, and 100% produced significant elevations of plasma osmolality, electrolytes, and AVT concentrations that plateaued with 50% seawater. Body mass and plasma AII levels were not significantly altered.

Comparison of salt gland function in birds adapted to fresh water with those adapted to 100% seawater showed some differences in concentrating and secretory capabilities.
Bromocriptine prevents the castration‐induced rise in porphyrin concentration in the harderian glands of the male syrian hamster, Mesocricetus auratus
Authors: Buzzell Gerald R. , Menendez‐Pelaez Armando , Porkka‐heiskanen Tarja , Pangerl Andreas , Pangerl Brigitte , Vaughan Mary K. , Reiter Russel J.
Published: June 2005

The Harderian glands in Syrian hamsters exhibit a striking sexual dimorphism. Male Harderian glands show two cell types and low levels of porphyrins and melatonin. Of the enzymes involved in the synthesis of melatonin, N‐acetyltransferase (NAT) and hydroxyindole‐O‐methyltransferase (HIOMT) show high and low activity levels, respectively. Female Harderian glands show but one cell type and have high porphyrin and melatonin levels, low NAT activity, and high HIOMT activity. In castrated males, the Harderian glands exhibit a female pattern of morphology, porphyrin levels, and indoleamine metabolism. In an attempt to determine whether prolactin is involved in this sexually dimorphic response of the Harderian glands, intact and castrated male and intact female hamsters were injected daily with 500 μg of bromocriptine, a dopamine agonist. Bromocriptine led to reduced serum prolactin levels in all groups. It had no apparent effect on the Harderian glands of intact males. In contrast, in castrated males bromocriptine prevented the postcastrational rise in porphyrin levels but had no effect on NAT or HIOMT activities. In females, bromocriptine treatment had no effect on prophyrin concentrations or HIOMT activity; it led to a statistically significant increase in NAT activity. We propose that testosterone inhibits Harderian porphyrin synthesis while dopamine or prolactin stimulates it.
Interaction of proteins RSV IV and RSV V in rat seminal vesicle secretion
Authors: Manco G. , Sansone G. , Abrescia P.
Published: June 2005

The RSV IV polypeptide, molecular weight ratio (Mr = 10,000), which is produced by the rat seminal vesicle, has previously been suggested to be associated with another polypeptide in the gland secretion (Higgins et al., '76). This study provides that RSV IV is a component of a protein shown by immunoassays, electrophoresis, and amino acid composition analysis to contain, together with RSV IV, the seminal vesicle secretory RSV V polypeptide (Mr = 13,000). This RSV IV‐RSV V complex (namely CFS protein) had an isoelectric point at pH 7.2 and an approximate molecular weight of 22,000 daltons. This complex inhibits the previously reported in vitro binding of the isolated RSV IV to epididymal sperm cells, thus suggesting a functional role for the RSV IV‐RSV V interaction.
Synthesis and activity of Xenopus laevis oocyte tyrosinase
Authors: Kidson S. H. , Fabian B. C.
Published: June 2005

This study investigates the mechanisms that control pigment synthesis in Xenopus laevis oocytes. Although we find the molecular weight of oocyte tyrosinase to be similar to that of amphibian skin, we were unable to increase its activity by proteases or detergents, as has been reported for skin tyrosinase. On the other hand, by measuring the activity of polysomal‐bound enzyme, we were able to correlate increased tyrosinase activity with increased levels of enzyme synthesis. We therefore suggest that in oocytes, the activity of tyrosinase is primarily dependent on its synthesis, whereas in skin, the rate‐limiting step is the post‐translational activation of the enzyme. We speculate on these differences in relation to the functional role of melanin in skin and oocytes.
Histoincompatibility in a low invertebrate, Hydractinia echinata: Analysis of the mechanism of rejection
Authors: Lange R. , Plickert G. , Müller W. A.
Published: June 2005

The colonial hydroid Hydractinia echinata is able to discriminate between self and non‐self. Encounters between isogeneic, or allogeneic but histocompatible, colonies of this hydroid result in fusion, whereas incompatible colonies do not fuse but display a peculiar mode of rejection. A special type of nematocyte, the microbasic mastigophore, which occurs exclusively in the stolon compartment of a colony, migrates to and accumulates at contact sites. Here these nematocytes adjust their cnidocils toward the alien tissue and discharge their threads nearly synchronously. Later incoming nematocytes discharge without delay upon arrival. Nematocytes move to and accumulate at contact sites in both compatible and incompatible encounters. However, only contact between incompatible animals causes the discharge of the nematocytes.

Permanent contact between incompatible competitors leads to an increase in the density of microbasic mastigophores from 12 to a maximum of 450 per mm stolon length. As a consequence the stolons acquire a hyperplastic appearance.

Labeling experiments indicate that stem cells or precursor cells are sensitive to the contact stimulus shortly before or during the S‐phase of the cell cycle. Differentiation to mature microbasic mastigophores takes 4 days.

Upon interruption of contact, the density of microbasic mastigophores is regulated down to the normal level. Supernumerary cells are removed by phagocytosis.
Sperm basic proteins in the turtle Chrysemys picta: Characterization and evolutionary implications
Authors: Chiva M. , Kulak D. , Kasinsky H. E.
Published: June 2005

Basic proteins in the sperm nuclei of reptiles have been classified cytochemically as type 3 intermediate proteins (Kasinsky et al., '87) or electrophoretically as type 1 protamines (Elsevier and Pieau, '88) according to Bloch's ('69) classification scheme. In this paper we have purified the sperm basic proteins of the painted turtle Chrysemys picta and show that they display considerable microheterogeneity, like the protamines of some fishes and other vertebrates. In addition, the amino acid composition of C. picta sperm basic proteins is very similar to that of protamines in birds (Chiva et al., '87), although those of the turtle lack tyrosine and contain low amounts of lysine and histidine. These facts allow us to relate reptilian sperm basic proteins to the main evolutionary line of vertebrate protamines and to discuss possible mechanisms for the macroevolutionary trend of relative constancy of sperm basic proteins in reptiles, birds, and mammals.
Neurohumor effects on crustacean haemocyanin oxygen affinity
Authors: Morris S. , McMahon B. R.
Published: June 2005

Various monoamines released as neurohormones from the pericardial organs of crab hearts were found to potentiate the oxygen affinity of haemocyanin from Cancer magister. Of the compounds tested, the catechol dopamine was the most active. Preincubation of the haemocyanin with a dopamine antagonist abolished the effect, indicating a specific site. Haemocyanin may also retard the rapid auto‐oxidation of dopamine that normally occurs at physiological pH.
Thyroid involvement in the relative photorefractoriness of Japanese quail, Coturnix coturnix japonica
Authors: Chaturvedi C. M. , Meier Albert H.
Published: June 2005

Thyroid involvement in the photosexual response was examined in photosensitive and relative photorefractory Japanese quail. Surgical thyroidectomy was carried out in gonadally regressed adult males held for several months on natural daylengths of 13.5–14.5 h. These birds were considered relative photorefractory (birds that are gonadally regressed at daylengths, 12–15 h, and initially stimulatory for gonadal growth in photosensitive quail). Following thyroidectomy and sham‐operation (controls), one‐half of each group were exposed for 30 days to light:dark (LD) 16:8 and then transferred to LD 13.5:10.5 for another 30 days. The remaining operated quail were exposed for the first 30 days to LD 8:16 and then transferred to LD 13.5:10.5 for another 30 days. In quail examined after the first 30 days, the left testis sizes were greatly increased in both thyroidectomized and control birds held on LD 16:8 but completely regressed in both groups held on LD 8:16. The photosexual responses are characteristic for both photosensitive and relative photorefractory quail held on such daylengths. After the second 30 days, the testes were strongly stimulated in both thyroidectomized and control quail that were transferred from LD 8:16 (first 30 days) to LD 13.5:10.5 (second 30 days). Apparently, photosensitivity had been reestablished during the first 30 days on short daylengths. In quail transferred from LD 16:8 (first 30 days) to LD 13.5:10.5 (second 30 days), the testis sizes were reduced in control birds indicating a relative photorefractory response to this intermediate daylength. However, the testis continued to grow in the thyroidectomized quail transferred from LD 16:8 to LD 13.5:10.5. The results indicate that the thyroid is important in the maintenance of relative photorefractoriness in Japanese quail.
A specific androgen‐binding protein (ABP) in Necturus testis and its zonal distribution
Authors: Singh Sanjay , Callard Gloria V.
Published: June 2005

The urodele amphibian Necturus maculosus has a zoned testis, which is advantageous for separating Leydig cells from germinal elements and for studying stage‐dependent biochemical changes. Using [3H]testosterone (T) in a standard binding assay and dextran‐coated charcoal (DCC) or Sephadex LH‐20 to separate free and bound steroids, we identified an androgenbinding protein (ABP) in Necturus testis cytosols. This protein was of high affinity (Kd = 10−9 M) and was saturable (Bmax = 10−9 M) and specific for androgen (T; 5 α‐dihydrotestosterone, DHT) but could be distinguished from the androgen receptor of Necturus testis by its relative abundance (300–550 fmol/mg protein), short half‐time of dissociation (3 min at 22°), inability to adhere to DNA‐cellulose, and absence from nuclear extracts. Additionally, when analyzed on sucrose gradients, the ABP of Necturus testis sedimented at 6–7 S in both low or high ionic strength buffers. In that estradiol (E2) is a poor competitor for T‐binding, this protein resembles a sex steroid‐binding protein previously identified in urodele serum but differs from the ABP and testosterone‐estradiol‐binding globulin (TEBG) of rodents, humans, goldfish, and sharks. It is differentially distributed within the testis, with the highest levels in immature lobular regions composed of Sertoli cells and germ cells in premeiotic stages and lower levels in regions composed primarily of Leydig cells. The cellular source and function of this protein in Necturus testis remain to be determined.
Localization of angiotensin‐converting enzyme in the trout gill
Authors: Olson Kenneth R. , Lipke David W. , Kullman Dixie , Evan Andrew P. , Ryan James W.
Published: June 2005

Angiotensin‐converting enzyme (ACE) was localized in perfused trout gills by measuring gill extraction of two radiolabeled ACE inhibitors, 125I‐351A (an iodinated derivative of lisinopril) and 3H‐RAC‐X‐65, and by autoradiography of gills perfused with 125I‐351A. A 125I‐351A pulse was preferentially extracted by the arterio‐arterial (AA) pathway (61.7% ± 1.8% extraction; mean ± SE, N = 4); the arteriovenous (AV) pathway extracted an additional 10%. Extraction by either pathway was reduced by simultaneous perfusion with 10−5 M unlabeled lisinopril. AA extraction of RAC‐X‐65 during continuous perfusion was maximal (75% ± 5%, N = 6) during the first few minutes of perfusion and decreased steadily to 38% ± 9% by 20 min and to less than 10% by 40 min. AV extraction of RAC‐X‐65 was negligible. Autoradiography of gills continuously perfused with 125I‐351A showed that the radiolabel was concentrated in the respiratory lamellae. The highest grain density was associated with the pillar cells nearest the medial (inner) lamellar margin. Afferent filamental arteries and afferent lamellar arterioles were labeled to a lesser extent. Relatively little label was found on the efferent lamellar arterioles or efferent filamental arteries. 125I‐351A binding was not evident in AV vessels. These findings support the hypothesis that the gill is an important site for formation of plasma angiotensin II and they suggest that enzymes associated with mammalian endothelial cells are also common to gill pillar cells.
Two histospecific enzyme expressions in the same cleavage‐arrested one‐celled ascidian embryos
Authors: Whittaker J. R. , Meedel Thomas H.
Published: June 2005

Fertilized eggs of the ascidian, Ciona intestinalis, were prevented from undergoing cytokinesis but not nuclear division by treatment with cytochalasin B. After appropriate times, such cleavage‐arrested multinucleate zygotes developed acetylcholinesterase of larval tail muscle and an alkaline phosphatase ordinarily localized in the larval endoderm tissues. Separate histo‐chemical reactions on one of a pair of samples taken from the eggs of single animals provided examples (6/34) in which the numbers of cytochalasin‐treated embryos displaying the respective reaction product overlapped sufficiently (15–29%) to indicate that some of the zygotes had developed both enzymes in the same uncleaved single cell. With an actual dual‐staining technique that can be applied to single cleavage‐arrested zygotes, 62% of those developing a strong alkaline phosphatase reaction also had a strong acetylcholinesterase reaction. In other experiments, quantitative measurements of enzyme activity in homogenates of 114 single cleavage‐arrested zygotes confirm directly that 18% of the zygotes produce both enzymes. There was no obligatory mutual exclusion of the potential for simultaneous expression of two tissue‐specific characteristics that would ordinarily be segregated into different lineages during early cleavages. The cytoplasmic determinants believed responsible for these histotypic expressions can apparently function independently in the same cell.
In vitro biosynthesis and secretion of rabbit epididymal secretory proteins: Regulation by androgens
Authors: Regalado F. , Nieto A.
Published: June 2005

The biosynthesis and secretion of epididymal proteins were studied in an in vitro system using explants from rabbit epididymis cultured in a defined medium. Epididymal explants actively incorporated [35S]methionine into cellular proteins, about 7% of them being secreted into the medium. SDS‐PAGE of the labeled proteins secreted to the medium showed regional differences in their synthesis and secretion along the epididymal tract. Castration resulted in the inhibition of the synthesis and secretion of at least two polypeptides of Mr 150,000 and 21,000, but at the same time induced the appearance of other polypeptides. Immunoprecipitations with a specific antibody indicated that the variations in the amounts of the secreted 21 kDa component were associated with differences in its rate of synthesis. Epididymis from immature rabbits synthesized some polypeptides that are repressed in the adult state. The results suggest a dual effect of testosterone on rabbit epididymal secretory proteins.
Presence of thermal hysteresis producing antifreeze proteins in the antarctic mite, Alaskozetes antarcticus
Authors: Block William , Duman John G.
Published: June 2005

The presence of hemolymph thermal hysteresis antifreeze proteins is described in both the nymphs and adults of the Antarctic oribatid mite, Alaskozetes antarcticus collected from Signy Island in the South Orkney Islands. These proteins, functionally similar to the antifreeze proteins of polar marine fish and certain cold‐tolerant insects, lower the freezing point of water by a noncolligative mechanism while not significantly affecting the melting point, thus producing their characteristic thermal hysteresis. This is the first finding of these proteins in mites and the first description of them in an arthropod from the southern hemisphere.
Levels of tyrosinase and its mRNA in coat‐color mutants of C57Bl/10J congenic mice: Effects of genic substitution at the agouti, brown, albino, dilute, and pink‐eyed dilution loci
Authors: Tamate Hidetoshi B. , Hirobe Tomohisa , Wakamatsu Kazumasa , Ito Shosuke , Shibahara Shigeki , Ishikawa Kiichi
Published: June 2005

The levels of tyrosinase activities, tyrosinase cross‐reacting material (TY‐CRM), and tyrosinase mRNA were determined for skins from five congenic strains of mice (Mus musculus) with different coat colors. The dopa oxidase activity and melanin formation activity were directly proportional to the abundance of TY‐CRM in all of the mutants. The levels of the enzyme activities and TY‐CRM were increased in brown (b/b) and dilute (d/d) mice, while they were reduced in agouti (A/A) and pink‐eyed dilution (p/p) animals. In albino (c/c) mice, the tyrosinase activities and melanin formation activity were scarcely detectable, and no TY‐CRM was observed.

Contrary to these, the levels of tyrosinase mRNA in agouti and albino mutants were almost the same as that in black mice, and those in brown and dilution mutants were 20–30% higher than that in black mice. These results indicate that the mutations at the brown and dilute loci exert their influence on the tyrosinase mRNA level, presumably by affecting the transcription of the tyrosinase gene, and that the mutations at the agouti and albino loci exert their influence on the TY‐CRM level by regulating translation of tyrosinase mRNA and/or post‐translation modification of the enzyme.
Melanophore dispersion in northern amphibian larva induced by exposure to cold
Authors: Moriya Tsuneo , Miyashita Yoko
Published: June 2005

Isolated tails from larvae of the northern amphibians Rana chensinensis and Hynobius retardatus showed light skin color in physiological salt solution at room temperature. However, when the tails were exposed to cold, they became dark. Microscopic observation revealed that exposure to cold caused reversible dispersion of melanin granules within integumental melanophores. There was no darkening, however, in the tail of the Xenopus tadpole at low temperatures, as the dispersion effect of melanophore‐stimulation hormone (MSH) on melanophores in Xenopus was blocked. Calcium ions are required for the action of MSH, but the effect of cold on melanophore dispersion observed in R. chensinensis and H. retardatus was not dependent on calcium ions. Beta adrenergic agents dispersed the melanophores of isolated tail from these amphibian larvae and propranolol antagonized the effect. However, during exposure to cold, this beta antagonist failed to inhibit the melanophore dispersion.
Discrete localization of distinct alkaline phosphatase isozymes in the cell surface of silkworm midgut epithelium
Authors: Azuma Masaaki , Eguchi Masaharu
Published: June 2005

Alkaline phosphatase (ALP) isozymes were localized in the larval midgut epithelium of the silkworm, Bombyx mori (Insecta: Bombycidae) by immunohistochemistry with the peroxidase‐conjugated antibody technique. The monospecific antibodies were produced against purified membrane‐bound ALP (m‐ALP) and soluble ALP (s‐ALP), respectively. The anti‐(m‐ALP)‐antibody did not cross‐react with the purified s‐ALP and vice versa. The m‐ALP was localized at the brush border of columnar cells in the middle and posterior midgut epithelium, but very weakly at that in the anterior midgut. In contrast, the s‐ALP was localized at the apical surface of goblet cells throughout the length of midgut. The extent of positive staining gradually increased toward the posterior midgut, where strong staining was also detected in the goblet cavity. From these results, it is concluded that two ALP isozymes distribute in the different cell types of Bombyx midgut epithelium and that the regional differentiation along the length of midgut exists on columnar and goblet cells.
Plasminogen activator activity is associated with neural crest cell motility in tissue culture
Authors: Erickson Carol A. , Isseroff R. Rivkah
Published: June 2005

We have examined the possibility that proteases such as plasminogen activator (PA) contribute to the extraordinary motile capability of neural crest cells. We show that trunk neural crest cells that migrate from isolated neural tubes in vitro produce PA and that the level of cell‐associated PA increases dramatically after 8 days in culture. This increase is not the result of differentiation or time in culture, because neural crest cell clusters that form on top of the neural tube and differentiate into pigment cells but are immotile produce very low levels of PA. If these clusters are removed from the neural tube and replated on a plastic substratum where they migrate, the level of PA associated with the cells increases dramatically, suggesting that PA production is associated with motility. Inhibitors of PA/plasmin activity significantly reduce neural crest cell motility in vitro, further supporting the idea that proteases are important in neural crest cell migration.
Cells from Rana pipiens gastrulae and arrested hybrid gastrulae show differences in adhesion to fibronectin‐Sepharose beads
Authors: Johnson Kurt E. , Silver Michael H.
Published: June 2005

Experiments were performed to examine adhesion of Rana pipiens gastrula cells and arrested hybrid gastrula cells to fibronectin‐Sepharose beads (FN‐beads). Blastula cells from both normal and hybrid embryos show poor adhesion to FN‐beads. Beginning at the early gastrula stage, however, normal cells show a progressively increasing tendency to adhere to beads. In two different arrested hybrid embryos, cells from all developmental stages lack the ability to adhere to beads. A third hybrid shows an increase and then a decrease in cell‐bead adhesion. A fourth hybrid shows a late increase in cell‐bead adhesion in animal‐half cells and no increase at all in vegetal‐half cells. Blastula‐stage cells have the ability to adhere to con A–beads and two kinds of Cytodex beads but will not adhere to FN‐beads. Similarly, some cells from arrested hybrid embryos lack the ability to adhere to FN‐beads but will adhere to con A–beads and cytodex beads. Observations in the light and scanning electron microscope show that normal cells form lamellipodia on FN‐beads and move about actively on them, much like they do in vivo on surfaces coated by fibrils containing fibronectin. For adherent hybrid cells attached to beads, one kind does so by small pseudopodia but does not move on them and another kind forms active lamellipodia at the tips of fusiform cells and moves on beads.
Pattern formation models and developmental constraints
Authors: Oster George F. , Murray James D.
Published: June 2005

Most schemes for embryonic pattern formation are built around the notion of lateral inhibition. Models of this type arise in many settings, and all share some common characteristics. In this paper we examine a number of pattern formation models and show how the phenomenon of lateral inhibition constrains the possible geometries that can arise.
Identification of puberty‐accelerating pheromones in male mouse urine
Authors: Nishimura K. , Utsumi K. , Yuhara M. , Fujitani Y. , Iritani A.
Published: June 2005

Gas chromatography–mass spectrometry was employed to identify the two volatile amines in male mouse urine. These amines were much less concentrated in urine of castrated males. The identified amines, isobutylamine and isoamylamine, were assayed for the potential of puberty acceleration in postweaning female mice. A total of 105 young female mice were exposed to one of the following five odors: distilled water (control), 0.1 M isobutylamine, 0.1 M isoamylamine, a mixture of 0.05 M isobutylamine and 0.05 M isoamylamine, or fresh male mouse urine. The mixture of these amines accelerated the vaginal opening of young females. Except for the control, all experimental odors accelerated the first vaginal estrus in ICR strain mice.
Cardiovascular anatomy and physiology of the black‐lip abalone, Haliotis ruber
Authors: Russell C. W. , Evans B. K.
Published: June 2005

The anatomy of the cardiovascular system of Haliotis ruber is described on the basis of observations from dissection, routine histology, and scanning electron microscopy of vascular casts and critical‐point dried tissue. The finest channels, lacunar tissue spaces, were around 10 μm and appear to lack an endothelial lining. A vascular connection, which exists between the cephalic arterial sinus and the cephalopedal venous sinus, may allow redirection of blood back to the heart during circumstances in which blood flow through the pedal vessels is prevented. 5‐Hydroxytryptamine (5‐HT) immunoreactive nerves were observed in atrial and ventricular walls, pericardium, cephalic arterial sinus, and afferent ctenidial vein. In unrestrained animals, pairs of in vivo pressure measurements were made from the right atrium, the ventricle, the pericardial chamber, the right efferent ctenidial vein, and the renal sac. All sites showed pulsatile pressures of low magnitude. Ventricular systolic:diastolic pressures were typically 8:4 cm water. In unrestrained animals, heart‐rate responses to changes in water temperature and pO2 were established and show H. ruber to be an imperfect regulator with respect to O2. Structural characteristics of the heart and vascular anatomy, pressure measurements, and heart rate are discussed in relation to whole animal function.
Relationships between spleen and respiration in the newt
Authors: Frangioni Giuliano , Borgioli Gianfranco
Published: June 2005

Specimens of newt, Triturus cristatus carnifex (Laurenti), anesthetized by submersion in 0.2% chlorbutol in tap water for 15 min, and then placed out of water in a damp terrarium, show hypertrophy of the spleen that in 2 hr gradually increases from 0.31 ± 0.12% with respect to body weight to 1.56 ± 0.26% (means and standard deviation calculated for groups of six animals). Other anesthetics either do not produce hypnosis (Veronal), do not have a prolonged enough effect (ethyl ether, chloroform), or induce vasodilatation, which prevents hypertrophy (MS‐222, urethane). The spleen hypertrophy, seen histologically to be due exclusively to blood congestion, is not caused by either a pharmacological effect of the chlorbutol or by the hypnotic state, as it does not appear in submerged anesthetized animals, unless the water is constantly stirred by a magnetic agitator, and can be reversed depending on the ventilation of the animal's skin. The spleen hoards blood when oxygenation is good (in air or stirred water) and releases this supply in the bloodstream when oxygenation is insufficient (in still water). The hypoxic “diffusion boundary layer”, which, in still water, forms around the immobile newts, hampers respiratory exchange and stimulates the spleen contraction. This mechanism and its relationship to oxygenation has been demonstrated statistically in unanesthetized newts as well, in both air and water, despite the interference of two contrasting factors—lung respiration and spontaneous motor activity—absent in anesthetized animals. Congestion and decongestion of the spleen are the physiological mechanisms compensating for variations in the level of oxygenation, an alternative to the “capillary recruitment” described by Poczopko (Zool Pol 6:161–175, 1957) and Burggren and Moalli (Respir Physiol 55:379–392, 1984) in many amphibians that appears to be absent in newts. The newt spleen, known to play a lesser role in erythropoiesis and destruction of aged erythrocytes than that traditionally assigned to it (Frangioni and Borgioli: J Exp Zool 243:409–416, 1987; 247:244–250, 1988), is thus of primary importance in respiration.