bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of proteins secreted by mouse embryos developing in vivo and in vitro
Authors: Nieder Gary L.
Published: June 2005

Proteins secreted by mouse blastocysts developing in vitro were compared to those from blastocysts developing in utero to determine if a simple medium supporting blastocyst development also supports secreted protein expression. In‐vivo embryos were collected on days 3, 4, or 5 of pregnancy and incubated in 35S‐methionine to produce conditioned medium containing released, labeled proteins. Embryos for culture were collected on day 3 and after 48 or 72 h labeled conditioned medium was produced. Labeled proteins were separated by two‐dimensional electrophoresis and compared using a digital image analysis system. Day 3 embryos did not release proteins in detectable amounts, although synthesis of intracellular proteins was substantial. Day‐4 and ‐5 blastocysts released proteins in increasing amount and complexity, consistent with previous results. When day‐3 embryos were cultured in medium containing 4 mg/ml BSA for 48 h, secreted protein patterns were similar but not identical to those of day‐5 uterine blastocysts. Although most of the proteins produced by uterine blastocysts were secreted by cultured embryos, differences were found in the relative quantities of certain proteins. Neither crystallized BSA nor polyvinyl alcohol at 4 mg/ml supported development of protein secretion as well as the crude fraction‐V BSA. Blastocysts restricted to the oviduct also exhibited quantitative differences in protein secretion patterns compared to uterine blastocysts. Thus, although blastocyst development and the expression of many secreted proteins are supported outside the uterus, the full pattern of secretion characteristic of the peri‐implantation embryo may be dependent on specific uterine influences.
Hypercapnic and hypocapnic hypoxia in the lugworm arenicola marina: A 31P NMR study
Authors: Kamp Günter , Juretschke Hans Paul
Published: June 2005

Using the noninvasive method of 31P nuclear magnetic resonance(NMR) spectroscopy, the influence of hypoxia on intracellular pH (pHi) and on the energy metabolism was studied in the lugworm Arenicola marina.

1. During hypercapnic hypoxia (induced by the animal itself), pHi dropped from 7.3 ± 0.1 (n = 6) to 6.5 ± 0.1 (n = 4) within 24 hours, whereas during hypocapnic hypoxia pHi decreased by only 0.3 units (n = 4). The change in pHw (pH of the ambient water) was similar: strong acidification from about 8.1 to 6.1 during hypercapnic and moderate acidification to 7.8 during hypocapnic hypoxia.

2. Mobilization of phosphagen (phosphotaurocyamine) occurred faster during hypercapnic than hypocapnic hypoxia. Anaerobic end products (propionate and acetate), however, accumulated to a greater extent during hypocapnic than hypercapnic hypoxia.

3. Conclusion: The severe acidosis found during hypercapnic hypoxia depends on the amount of CO2 accumulation rather than on the amount of glycolytic end products. On the other hand, the lower accumulation of glycolytic end products and the faster mobilization of phosphagen with severe acidosis seem to reflect a regulatory effect of pHi on anaerobic metabolism.
Ecdysteroids and regeneration in the fiddler crab Uca pugilator
Authors: Hopkins Penny M.
Published: June 2005

Regeneration of lost walking legs in the fiddler crab Uca pugilator is divided into three distinct phases—wound healing, basal growth, and proecdysial growth. By means of HPLC/RIA analysis of levels and composition of endogenous ecdysteroid hormones and in vitro assays of 14C‐leucine incorporation, we have determined that the transition between anecdysis and proecdysis is the point at which limb bud growth is most affected by ecdysteroids. The growth that occurs during proecdysis is programmed during the anecdysis/proecdysis transition by a small peak of ecdysteroids (Peak I). Early exposure to 20‐hydroxyecdysone at this critical window is necessary for further proecdysial growth of limb buds. The later peak of ecdysteroids (Peak II) seen in the hemolymph of these crabs during late proecdysis does not seem to be involved in the regeneration process.
Effect of maternal age on the incidence of digynic triploidy in LT/SV strain mice: Implications for the ovulation of primary and secondary oocytes in this strain
Authors: Speirs S. , Kaufman M. H.
Published: June 2005

LT/Sv strain mice ovulate both primary and secondary oocytes, which are fertilisable, giving rise to digynic triploid and normal diploid fertilised conceptuses, respectively. Since the proportion of primary and secondary oocytes ovulated in our earlier studies varied widely among females, we investigated whether the proportion of primary oocytes ovulated in LT/Sv strain mice was influenced by maternal age. Females 6, 12, 18, 24, and 30 weeks old were mated with F1 hybrid males. The females were autopsied on the 10th day of gestation, and the intact conceptuses or extraembryonic membranes analysed cytogenetically.

Since no selective loss of the triploids occurs up to the 10th day of gestation, analysis at this time also provides indirect information on the proportion of primary and secondary oocytes ovulated. We observed 1) that the overall incidence of triploidy decreased from 55% in the 6‐week‐old females to 6% in the 30‐week‐old group; 2) that the number of females from which both triploid and diploid embryos were recovered decreased with increased maternal age; 3) that a substantial decrease in the proportion of triploid embryos was observed in those females in which both triploid and diploid embryos were recovered, in relation to increased maternal age; 4) that there was no overall decrease in the total number of implants with increasing age; and 5) that there was no increase in the incidence of resorptions with increasing maternal age. We believe that no comparable relationship between the ovulation of primary and secondary oocytes and maternal age has previously been reported.
Regulation of body volume by the peripheral nervous system of the terrestrial slug Ariolimax columbianus
Authors: Martin Arthur W. , Deyrup‐Olsen Ingrith , Stewart Doris M.
Published: June 2005

Responses to mechanical and chemical stimulation have been studied in an in vitro preparation of the body wall of the land slug Ariolimax columbianus. This preparation (posterior chamber, PC) is separated from the head ganglia and therefore has only peripheral nervous control. The volume contained within the PC (normally filled with viscera and hemolymph) is determined by 1) contraction or relaxation of muscle cells, causing exchange of fluid between the PC and the attached manometer that controls pressure within the PC; 2) secretion by epithelial channel cells moving fluid from inside the PC to the outside across the epithelial surface.

The PC maintained at constant internal pressure responded to mechanical stimulation (at ca. 1 Hz) of the epithelium with a brief burst of secretion. Prolonged (45 minutes) stretch of the body wall by maintenance at 11 torr or above resulted in intermittent pulses of secretion and muscle contraction. At very high pressure muscle contraction was suppressed, and secretion volumes were huge, gradually restoring the volume of the PC to its initial value (autoregulation).

When PCs were immersed in fluid containing garlic extract, skin receptors responded, initiating secretion comparable to the effects of mechanical stimulation in both amount and duration. Other chemicals (including capsaicine, cysteic acid, and geraniol) known to be aversive to pulmonates in vivo did not activate the secretory response.
Isosmotic swelling of skate (Raja erinacea) red blood cells causes a volume regulatory release of intracellular taurine
Authors: Goldstein Leon , Brill Susan
Published: June 2005

Animal cells swell when placed in a hypotonic medium and then regulate their volume by releasing intracellular solutes. The aim of this study was to determine whether hypoosmolarity or cell swelling is the stimulus that triggers the release of solutes. Swelling skate red blood cells (RBC) by placing them in isosmotic media containing rapidly penetrating solutes (NH4Cl, ethylene glycol) caused increased release of taurine from the cells. Isosmotic swelling also increased the cellular levels of radiolabeled diacylglycerol, a second messenger previously implicated in volume regulation by skate RBC. These results indicate that the release of intracellular solutes by hypoosmotically stressed skate RBC is brought about by cell swelling.
Phenotypic characterization of the transgenic mouse insertional mutation, legless
Authors: McNeish John D. , Thayer Jean , Walling Karen , Sulik Kathy K. , Potter S. Steven , Scott William J.
Published: June 2005

In this report, we describe the dysmorphologic phenotype associated with the transgenic insertional mutation legless. This autosomal recessive, perinatally lethal mutation results in an interesting pleiotropic array of congenital malformations. The phenotype of the legless mutation in homozygous perinatal mutants is compared to wild‐type nontransgenic and heterozygous siblings. Skeletal, craniofacial, and visceral malformations are characterized. We have observed by skeletal analysis a consistent loss of distal hindlimb structures, as well as the loss of distal forelimb structures with a predilection for the preaxial side of the developing forelimb. Craniofacial malformations commonly observed appear to represent a range of severity of affect, with the mildest manifestation evident as apparently shallow lateral clefts of the upper lip and mild midfacial clefts accompanied by clefts of the secondary palate. At the severe end of the spectrum, the midline clefts of the face (and secondary palate) are very wide, with obvious accompanying frontonasal encephaloceles and overt lateral clefts of the upper lip. Examination of the mutant brain has demonstrated marked defects in the anterior structures, particularly the olfactory lobes and cerebrum, in greater than 90% of the brains studied. Observation of the internal viscera has identified transposition of thoracic and abdominal organs in approximately 50% of the mutant offspring. The limb, head, and visceral defects were not observed in the wild‐type nontransgenic or heterozygous siblings. Transgenic insertional mutations leading to congenital malformations are useful because the transgene sequence may serve as a tag to facilitate molecular retrieval. Analysis of the flanking DNA sequences will allow the identification of the interrupted gene. A complete description of the mutant phenotype will assist in the understanding of this genetic locus.
Characterization of membrane‐associated actin in boar spermatozoa
Authors: Peterson R. N. , Bozzola J. J. , Hunt W. P. , Darabi A.
Published: June 2005

Biochemical, immunological, and electron microscopic methods have been used to provide semi‐quantitative estimates and to localize actin in membranes of boar spermatozoa. Immunoblots, using a monoclonal antibody raised against actin from chicken gizzard, detected the protein in caput and cauda sperm plasma membranes. Immunoassay indicated that approximately 1% of the total plasma membrane protein was actin. Monomeric actin accounted for more than onehalf of the membrane actin. Approximately 30–40% of plasma membrane actin was insoluble in Triton X‐100, and approximately 10% of the total actin remained insoluble after treatment with guanidine hydrochloride. The presence of F‐actin in sperm plasma membranes and in plasma membrane detergent‐insoluble proteins was detected by fluorescence microscopy using the specific probe NBD phallacidin. When S1 myosin subfragments attached to colloidal gold were used to localize F‐actin by electron microscopy, the label was restricted to the outer acrosomal membrane of intact epididymal and ejaculated sperm. Filaments appeared in short arrays along the anterior region of the membrane. S1/gold labeled detergent‐insoluble plasma membrane fractions but did not label the plasma membrane in intact sperm. Filaments were least prominent in intact caput spermatozoa and most prominent in ejaculated spermatozoa. We conclude that most actin associated with sperm membranes is in monomeric form in boar spermatozoa, but that actin filaments or protofilaments are components of the outer acrosomal membrane. These filaments may also associate with the plasma membrane overlying the acrosome.
Method for measuring submicrogram quantities of Cl− in minute tissue samples
Authors: Quinn R. H. , Pierce S. K.
Published: June 2005

Methods for measuring submicrogram quantities of Cl− are not as widely used by biologists as analogous measurements for small quantities of inorganic cations such as Na+ or K+. A portion of a project measuring osmolyte change during cell volume regulation in molluscan ganglia required Cl− measurement in minute tissue samples. We applied two methods to the determination of Cl− in these samples. Using ion chromatography on a high‐performance liquid chromatograph, submicrogram quantities of Cl− were measured in circumesophageal nerve rings from an opistobranch mollusc, Elysia chlorotica, with quantities of tissue as small as 0.0600 mg dry weight. Cl− was also measured in the range of 3–6 μ from larger quantities of ganglia by a less sensitive method, mercuric nitrate titration with a visual endpoint. Estimates of intracellular Cl−, calculated by subtracting estimates of extracellular Cl− from total tissue Cl−, showed that intracellular Cl− in the ganglia is reduced in response to a reduction in salinity. Thus Cl− loss contributes to osmotic readjustment of the ganglia cells during low‐salinity stress.
Enzymatic and immunological properties of alkaline phosphatase of bullfrog
Authors: Goseki M. , Oida S. , Sasaki S.
Published: June 2005

Enzymatic and immunological properties of alkaline phosphatase (ALPase) in several tissues of bullfrog (Rana catesbiana) were investigated. Inhibition and thermal inactivation studies showed that bullfrog ALPases in kidney, liver, and intestine had similar enzymatic properties. In addition, mouse antiserum against bullfrog liver ALPase cross‐reacted with kidney and intestine enzymes as well as with liver enzyme. These results suggest that a single phenotype of ALPase exists in all tissues of bullfrog in contrast to two or three isoenzymes in mammals.
Seasonally occurring lectins from the bryozoan Bugula neritina
Authors: Colon‐Urban Rita , Oppenheim Joel D.
Published: June 2005

Two different lectins (termed BnA‐I and BnA‐II) with distinct carbohydrate specificities were identified and subsequently isolated from the marine bryozoan Bugula neritina. BnA‐I hemagglutinating activity was inhibited by N‐acetylated hexosamines, their polymers, and glycoproteins rich in these moieties. BnA‐II‐induced hemagglutination was not blocked by any simple sugars but could be inhibited by several complex glycoproteins (e.g., thyroglobulin and orosomucoid). Both lectins required the presence of Ca+ + for reactivity and were purified by affinity chromatographic procedures. Purified BnA‐I was determined to have a native molecular weight of 240 Kd and appeared to be a hexameric homopolymer while BnA‐II was shown to be a 65–70 Kd monomer. Both lectins showed seasonality in expression, BnA‐I appearing in animal extracts prepared in the spring and fall while BnA‐II was expressed only during the summer and winter.
Fully differentiated Xenopus eye fragments regenerate to form pattern‐duplicated visuo‐tectal projections
Authors: Wunsh Lauren M. , Ide Charles F.
Published: June 2005

In order to determine if differentiated Xenopus retina is capable of undergoing regeneration and duplicative pattern formation, we devised a new surgical technique for removal of the temporal two‐thirds of the retina. In a series of progressively older larval eyes starting with late tailbud stage embryos (stage 38) and extending to limb‐bud stage tadpoles (stage 48), nasal onethird‐sized eye fragments successfully regenerated to form nearly normal sized eyes over 75% of the time. Histological preparations showed that early wound healing involved the formation of a neuroepithelium at the ventro‐temporal region of the fragment. The pigmented retinal epithelium and associated retinal tissue appeared to be involved in this process. Animals from each stage were reared through metamorphosis and electrophysiologic techniques were employed to determine visuo‐tectal projections. Seventy percent of stage 38 animals showed evidence of pattern‐duplicated projections. Ninety percent of their responding tectal points showed duplicate innervation from two retinal regions. Older animals (stages 44 to 48) showed less duplication. Only 52% of their responding tectal points duplicated (P < 0.001). Thus, fully differentiated Xenopus retina can undergo regeneration and duplicative pattern formation similar to that shown by embryonic retinal tissue.
Microvasculature of the nasal salt gland of the duckling, Anas platyrhynchos: Quantitative responses to osmotic adaptation and deadaptation studied with vascular corrosion casting
Authors: Hossler Fred E. , Olson Kenneth R.
Published: June 2005

The three‐dimensional microvasculature of the nasal salt gland of the duckling was studied by vascular corrosion casting and scanning electron microscopy. Changes in the vascular volume of the gland in response to osmotic stress were also determined using cast weights and densities. The richly vascularized gland is supplied on its medial surface by large branches of the supraorbital and ethmoidal arteries. Numerous arterial branches enter the gland and distribute to lobes via the interlobar connective tissue. Lobar arterioles penetrate to the periductal areas of the lobes before dividing into capillaries supplying the ductal epithelium and secretory tubules. Capillaries envelope the secretory tubules and run radially from the ducts toward the lobe periphery, so that blood flows counter to the tubular secretion. Blood is collected via venous plexuses seen as distinct drainage units on the periphery of each lobe. Veins exhibit large numbers of bicuspid valves. Following 1 day and 4 days of osmotic loading (feeding 1% NaCl), vascular volume of the gland increased fivefold and ninefold, respectively, a response that precedes and exceeds that of the gland weight or Na,K‐ATPase activity. When salt water‐adapted ducklings were fed fresh water for only 24 hr (deadaptation), vascular volume fell to 2.8 times the control level. Changes in blood flow to the gland during osmotic adaptation and deadaptation are rapid and dramatic and may represent the initial steps in the control of gland secretion.
Oogenesis in Fundulus heteroclitus. VI. Establishment and verification of conditions for vitellogenin incorporation by oocytes in vitro
Authors: Kanungo Jyotshnabala , Petrino Teresa R. , Wallace Robin A.
Published: June 2005

A procedure was developed for studying vitellogenin (VTG) incorporation by vitellogenic oocytes of Fundulus heteroclitus in vitro. Since homologous VTG can be obtained from this animal only with great difficulty, the use of [32P]VTG from Xenopus laevis was explored as an alternative. Vitellogenic as well as maturational‐stage oocytes were found to sequester X. laevis [32P]VTG from the medium, and incorporation was found to be linear with time for at least up to 12 hr. Once incorporated into the oocyte, [32P]VTG did not appear to undergo turnover. The effect of different [32P]VTG concentrations on incorporation indicated that the uptake mechanism was saturable. Unlabeled F. heteroclitus VTG and X. laevis VTG were also found to compete effectively with X. laevis [32P]VTG, whereas bovine serum albumin did not. These results represent the first documentation of a successful culture system for receptor‐mediated VTG incorporation by teleost oocytes.
Neurotransmitter‐related enzyme acetylcholinesterase in juveniles of Concholepas concholepas (Mollusca; gastropoda; muricidae)
Authors: González M. , Perelman A. , Fuentes M. E. , Castilla J. C. , Labarca R. , Brandan E. , González‐Plaza R. , Inestrosa Nibaldo C.
Published: June 2005

With the aim of understanding the organization of the nervous system in the Prosobranchia gastropod Concholepas concholepas, we studied the properties, specificity, sedimentation coefficient, and solubility of the cholinergic enzyme, acetylcholinesterase (AChE). It was found that 95% of the esterase was inhibited by BW284c51 dibromide but not by iso‐OMPA, which is consistent with the specificity of AChE. The calculated Km 0.22 mm is eight to ten times higher than are the Kms for AChE of other invertebrates and similar to the values reported for fishes and vertebrates.

The AChE shows a maximal activity around 22°C, has a glycoproteic character, and presents sedimentation coefficients of 6.5 S and 10.5 S. Most of this AChE activity is soluble under low ionic strength conditions; however, the enzyme aggregates in the absence of detergents.

In conclusion, our evidence indicates the presence of a well‐recognized molecular marker that could be useful for the study of the development of Concholepas concholepas.
Effects of osmolality and solutes on performance of shark heart mitochondria
Authors: Lea Malcolm , Hillman Stanley
Published: June 2005

Dogfish shark heart mitochondria isolated from Squalus acanthias were exposed to increasing concentrations of mannitol/sucrose, trimethylamine oxide (TMAO), betaine, and urea. For all but urea, respiratory control ratios (RCR) and rates of oxygen uptake (V̇O2) in the presence of malate/glutamate were low in basal medium (220 mOsm), increased with solute concerntration to about 420–870 mOsm, and declined in the highest concentrations (1,150 mOsm). Increasing urea concentration up to about 1,150 mOsm had relatively little effect on RCR or V̇O2. The results were not changed significantly by prolonged incubation in these media or by the addition of 0.3 M urea to either mannitol/sucrose or TMAO media. We conclude that, like mannitol/sucrose, betaine, and probably TMAO permeate shark heart mitochondria slowly or not at all, but that urea readily permeates the mitochondria and is thus osmotically inactive. The highest V̇O2 values were obtained in media at 580 mOsm, hypoosmotic to shark blood (897 mOsm) and to local seawater (879 mOsm) but approximately isoosmotic to blood without the osmotic contribution of the permeant urea. We conclude that V̇O2 is superior to RCR as a comparative measure of mitochondrial activity.
Induction of maturation of atlantic croaker oocytes by 17α,20β,21‐trihydroxy‐4‐pregnen‐3‐one in vitro: Consideration of some biological and experimental variables
Authors: Patiño Reynaldo , Thomas Peter
Published: June 2005

We characterized the in vitro control of germinal vesicle breakdown (GVBD) by 17α,20β,21‐trihydroxy‐4‐pregnen‐3‐one (20β‐S) in intact ovarian follicles of gonadotropin‐primed Atlantic croaker. 20β‐S‐induced GVBD was determined in relation to ovarian (oocyte) morphology, duration of incubation, steriod metabolism, and interaction with other steroids. The rate of GVBD in vitro in the absence of exogenous steriod was positively correlated with initial stage of ovarian morphological development. Maximal responsiveness to 20β‐S was seen in ovaries with oocytes showing the first signs of morphological maturation. Dose‐response experiments with 20β‐S and 17α,20β‐dihydroxy‐4‐pregnen‐3‐one (17α,20β‐P) over a range of incubation times yielded similar results for both steriods, suggesting that conversion of 17α,20β‐P to 20β‐S is not required for 17α,20β‐P‐induced GVBD. The ED50 of these steroids markedly decreased with increasing incubation times. Comparisons between patterns of follicular transformation of various radiolabelled steroids to 20β‐S and their respective activities (using unlabelled steroids) in the GVBD bioassay suggested that, in addition to 17α,20β‐P, progesterone has some intrinsic maturational activity. However, the maturational effects of 11‐deoxycortisol and pregnenolone may be explained by their conversion to 20β‐S. For the first time in any vertebrate, we showed that the proposed maturation‐inducing steroid (20β‐S) is not significantly transformed to any extractable, potentially active metabolite by intact, maturing ovarian follicles. These findings strongly suggest that 20β‐S is the terminal product of the MIS biosynthetic pathway in Atlantic croaker ovaries. Estradiol had no acute effects on 20β‐S‐induced GVBD. However, testosterone decreased and cortisol augmented the maturational activity of 20β‐S. Excess progesterone reduced the activity of a maximally effective dose of 20β‐S, but pregnenolone was without effect. The effects of these steroids on 20β‐S‐induced GVBD are discussed in relation to their possible interactions with 20β‐S at the MIS receptor level.
Analysis of myosins from lobster muscles: Fast and slow isozymes differ in heavy‐chain composition
Authors: Li Youlin , Mykles Donald L.
Published: June 2005

The contractile speed of striated muscle is correlated with myosin adenosine triphosphatase (ATPase) activity. In crustaceans, ATPase activity in fast muscle is about four‐fold greater than that in slow muscle. Slow and fast myosins were purified from the crusher claw closer and the deep abdominal muscles, respectively, of teh American lobster, Homarus americanus, and analyzed by peptide mapping, chymotryptic digestion, and two‐dimensional polyacrylamide gel electrophoresis (PAGE). Peptide mapping of myosin heavy chains with Staphylococcus aureus V8 protease produced seven peptides unique to slow‐muscle myosin and 11 peptides unique to fastmuscle myosin. Heavy‐chain fragments produced by chymotryptic digestion of native myosin differed in molecular weight and isoelectric point between the two muscle types, suggesting possible differences in the flexible hinge region in the rod portion of the molecule. In contrast, twodimensional PAGE showed that the corresponding light chains of both fast and slow myosins were identical in size and net charge. Therefore, the molecular basis of the difference in ATPase activities between fast‐ and slow‐muscle myosins can be attributed solely to heavy‐chain isoform composition.
Inhibition of serotonin‐induced oocyte maturation by a Spisula factor
Authors: Kadam Arjun L. , Koide Samuel S.
Published: June 2005

A factor that blocks serotonin (5‐hydroxytryptamine, 5‐HT)‐induced maturation of Spisula oocytes was purified from Spisula oocytes by ultrafiltration through a PM‐10 membrane, charcoal adsorption, and reversed‐phase HPLC on a Partisil ODS‐3 column, The oocyte factor is a heat‐stable, non‐proteinaceous compound with an estimated Mr of less than 1,000 Da. It blocked 5‐HT‐induced maturation of Spisula ooctyes at concentrations ranging from 10 to 100 μg/ml. It did not influence KCl‐ or potassium‐ glutamate‐induced maturation of Spisula oocytes or the maturation of mouse, Chaetopterus, Xenopus, or Asterias oocytes. The oocyte substance may function as a modulator of 5‐HT action and/or be the endogenous meiotic arresting factor in Spisula oocytes. At concentrations exceeding 100 μl/ml, the oocyte factor induced formation of blebs and cytoplasmic droplets.
Biosynthesis of 17α,20α‐dihydroxy‐4‐pregnen‐3‐one from 17α‐hydroxyprogesterone by spermatozoa of the common carp, Cyprinus carpio
Authors: Asahina Kiyoshi , Barry Terence P. , Aida Katsumi , Fusetani Nobuhiro , Hanyu Isao
Published: June 2005

Isolated sperm of the common (Cyprinus carpio) were incubated with 4‐14C‐labeled 17α‐hydroxyprogesterone at 22°C for 60 min; the medium was extracted, and the products were separated by thin‐layer chromatography (TLC). An autoradiogram of the TLC plate showed that a single major metabolite was produced, which had an Rf value lower than that of 17α,20β‐dihydroxy‐4‐pregnen‐3‐one (17α,20β‐diOHprog) but which was identical to that of its isomer, 17α,20α‐dihydroxy‐4‐pregnen‐3‐one (17α,20α‐diOHprog). The metabolite behaved identically on thin‐layer chromatograms to authentic 17α,20α‐diOHprog after both acetylation and oxidation, and had the same retention time as authentic 17α,20α‐diOHprog when separated by highperformance liquid chromatography (HPLC). The identity of the metabolite was confirmed by recrystallizing it to a constant specific activity after repeated crystallization with authentic 17α,20α‐diOHprog. These results indicate that the sperm cells of common carp contain the enzyme 20α‐hydroxysteroid dehydrogenase and have the capacity to produce high levels of 17α,20α‐diOHprog in the presence of 17α‐hydroxyprogesterone.
Fatty‐acyl coenzyme A pool in liver of rainbow trout (Salmo gairdneri): Effects of temperature acclimation
Authors: Hazel Jeffrey R. , Livermore Rochelle C.
Published: June 2005

The size and composition of the hepatic acyl‐CoA pool were determined in quickly frozen liver tissue of rainbow trout (Salmo gairdneri) acclimated to 5° and 20°C. Concentrations of 14:0‐, 16:1‐, 18:3‐, 20:2‐, 20:3‐, and 24:1‐CoA were significantly higher while proportions of 18:0‐, 18:1‐, 20:1‐, and 20:4‐CoA were significantly lower in warm‐ than cold‐acclimated trout. In spite of these differences, neither the size (although 28% larger in warm‐ than cold‐acclimated trout), total content of unsaturated acyl‐CoAs, average chain length, nor the degree of unsaturation of the acyl‐CoA pool was significantly influenced by acclimation temperature. Arachidonic acid (20:4n6) was the only polyunsaturated fatty acid present in significantly higher quantities in the acyl‐CoA pool of cold‐ than warm‐acclimated trout. Levels of n‐3 acids were similar in both acclimation groups, while proportions of n‐9 and n‐6 acids increased and decreased, respectively, with cold acclimation. It is concluded: 1) that the composition of the acyl‐CoA pool is unlikely to influence significantly the acyl chain composition of membrane lipids and 2) that the temperature dependence of substrate preference for the enzymes of phospholipid biosynthesis and turnover is likely to play a major role in determining which molecular species of phospholipid will accrue as environmental temperature changes.
Role of sialic acid in exogenous protein accumulation and water retention by the egg jelly of the salamander Ambystoma macrodactylum
Authors: Berner Nancy J. , Ingermann Rolf L.
Published: June 2005

The jelly coat of eggs from the salamander Ambystoma macrodactylum is capable of binding and accumulating a high concentration of exogenous protein from a dilute incubation medium. This binding appears to be due to negatively charged moeities of the jelly structure. To examine whether sialic acid was responsible for the binding of exogenous protein as well as water retention, and thus the structural rigidity of the jelly, sialic acid was chemically removed from the jelly. There appeared to be a linear relationship between the sialic acid content of the jelly and the amounts of exogenous protein and water retained by the jelly. Furthermore, removal of about 90% of the sialic acid was associated with 89% and 70% decreases in accumulated hemoglobin and water content, respectively. The data are therefore consistent with the hypothesis that sialic acid is the exogenous protein binding site. The data are also consistent with the hypothesis that sialic acid is responsible for most of the water retention and thus the swollen state of the egg jelly.
Length‐tension and histochemical properties of select shoulder muscles of the savannah monitor lizard (Varanus exanthematicus): Implications for function and evolution
Authors: Young B. A. , Magon D. K. , Goslow G. E.
Published: June 2005

We explored the mechanical properties of four shoulder muscles of the Savannah Monitor Lizard (Varanus exanthematicus) and related these to locomotion. We studied the biceps brachii, supracoracoideus, two parts of the latissimus dorsi, and two parts of the pectoralis muscles by measuring twitch contraction time, peak tetanic tension, and contractile fatigue resistance to repetitive stimulation. In addition, we generated length‐passive and length‐active tension curves at those muscle lengths used during slow and moderate speed walking. Finally, we used conventional histochemistry to identify anatomical compartments within these muscles. Major findings include (1) the length‐active tension of the biceps brachii, supracoracoideus, both parts of the latissimus dorsi, and the pectoralis remains near peak value over a range of muscle lengths associated with normal limb movement, (2) all muscles possess a mean twitch contraction time of between 65 and 70 msec (24°C), (3) all muscles are relatively fatiguable, and (4) evidence for anatomical compartments exists for the latissimus dorsi, pectoralis, and supracoracoideus.

We compared the data for the pectoralis of V. exanthematicus to that for the domestic pigeon (Columba livia) in an effort to identify features of musculoskeletal design which may have accompanied the evolution of flight. We conclude that at least two factors were important: (1) the development of a capacity for sustained, aerobic contraction, and (2) a rearrangement of some of the anterior pectoralis fascicles so that they arise from the furcula. The latter provides for a distinct protractive component to the humerus, which is important during downstroke in some forms of flapping flight.
Spermatogenesis in XO,Sxr mice: Role of the Y chromosome
Authors: Kot Mary C. , Handel Mary Ann
Published: June 2005

The goal of this investigation was to evaluate the role of the Y chromosome in spermatogenesis by a quantitative and qualitative analysis of spermatogenesis as it occurs in the absence of a significant portion of the Y chromosome, i.e., in XO,Sxr male mice. Although these mice have the testis‐determining portion of the Y chromosome on their single X chromosome, they lack most of the Y chromosome. Since it was found that all sperm‐specific structures were assembled in a normal spatial and temporal pattern in spermatids of XO,Sxr mice, the genes controlling these structures cannot be located on the Y chromosome outside of the Sxr region, and are more likely to be on autosomes or on the X chromosome. In spite of the assembly of the correct sperm‐specific structures, spermatogenesis was not quantitatively normal in XO,Sxr mice and significantly reduced numbers of spermatids were found in the seminiferous tubules of these mice. Furthermore, two size classes of spermatids were found in the testes of XO,Sxr mice, normal and twice‐normal size. These findings are suggestive of abnormalities of meiosis in XO,Sxr spermatocytes, which lack one of the two sex chromosomes, and may not implicate function of specific genes on the Y chromosome. Morphological abnormalities of spermatids, which were not unique to XO,Sxr mice, were observed and these may be due to either a defective testicular environment because of reduced numbers of germ cells or to the lack of critical Y chromosome‐encoded products. Since pachytene spermatocytes of XO,Sxr mice exhibited a sex vesicle, it can be concluded that the assembly of this structure does not depend on the presence of either a complete Y chromosome or the pairing partner for the X chromosome.
Electrophoretic characterization of proteins in oviduct fluid of cows during the estrous cycle
Authors: Gerena R. L. , Killian G. J.
Published: June 2005

This study was undertaken to examine the in vivo protein composition of the bovine oviduct during the estrous cycle. Oviduct fluid was collected daily from four oviductcannulated dairy cows for a total of four complete estrous cycles. Fluid secretion followed a definite cyclic pattern, with maximum secretion occurring at estrus in all cycles. Protein concentration fluctuated during the cycle and varied among animals. In general, protein concentration was lower at the time of estrus. Total protein in oviduct fluid, however, was higher around estrus, indicating increased transudation or secretion by the oviduct. One‐dimensional SDS‐PAGE separation revealed the protein pattern of oviduct fluid to be generally similar to that of blood serum and follicular fluid. Two proteins appeared to be oviduct‐specific. The first, a protein of approximately 47 kDa, was evident in oviduct fluid throughout the estrous cycle. The second protein, evident as a broad diffuse staining band above albumin, appeared for only 3–4 days at or near ovulation. This protein had a molecular weight of 80–95 kDa and stained positive for carbohydrate with periodic acid‐Schiff reagent. These studies indicate that the in vivo protein composition of oviduct fluid varies with the estrous cycle, and that around estrus, an oviduct‐specific glycoprotein is present.
Calcium ion in chromatic nerve transmission and melanophore movements in teleosts
Authors: Miyashita Yoko , Moriya Tsuneo
Published: June 2005

Ca‐ionophore A23187 was examined for its action on innervated and denervated melanophores of the guppy Lebistes reticulatus and the Siamese fighting fish, Betta splendens.

This Ca‐ionophore (5 × 10−6 M) induced melanin aggregation in innervated melanophores of both species. This aggregating response disappeared in the presence of an alpha‐adrenolytic agent, phentolamine.

However, in denervated skin melanophores of these fish, A23187 failed to aggregate melanosomes.

An inhibitor for intracellular calcium release, 8‐(N,N‐diethylamino)octyl 3,4,5‐trimethoxybenzoate hydrochloride (TMB‐8), inhibited the melanophore‐aggregating responses induced by A23187 and by electrical stimulation of nerves.

In the presence of TMB‐8 (less than 10−4 M), the melanin aggregation response to norepinephrine (NE) commenced normally and both the rate and degree of aggregation were identical to those in saline solution alone. However, the time course of re‐dispersion from the aggregated state after NE treatment clearly shortened with TMB‐8. This action of TMB‐8 on the response to NE was enhanced in calcium‐free saline solution.

We discuss the possible roles and origin of calcium ions in chromatic nerve transmission and melanophore movements in teleost fish.
Sperm histones and chromatin structure of the “primitive” sea urchin Eucidaris tribuloides
Authors: Vodicka M. , Green G. R. , Poccia D. L.
Published: June 2005

The “primitive” sea urchin Eucidaris tribuloides resembles the advanced sea urchins (euechinoids) in many respects, yet some features of its biochemistry and morphogenesis are more similar to other echinoderms such as starfish or sea cucumbers. Two unique characteristics of the sperm chromatin of all known euechinoids are an extremely long average nucleosomal repeat length and the presence of two male germ‐line‐specific histone variants, Sp H1 and Sp H2B. Histone composition and nucleosomal repeat length of the sperm chromatin of Eucidaris were compared to those of several euechinoids and a starfish. Eucidaris sperm chromatin contained large H1 and H2B histone variants typical of euechinoids. The H1 was about nine amino acids smaller than Sp H1 of the advanced urchin Strongylocentrotus purpuratus. Its Sp H2B molecules were the same size as in the euechinoids. Peptide maps showed that N‐terminal regions of Sp H1 and Sp H2B contained repeating basic amino acid motifs characteristic of euechinoids. The smaller size of Eucidaris H1 is accounted for by a smaller C‐terminal region. The repeat length of Eucidaris sperm chromatin was slightly shorter than that of two euechinoids, but significantly larger than starfish, which lacks a large H2B. The Sp H2B gene of Eucidaris was expressed during spermatogenesis in the same cell types as for S. purpuratus. Thus Sp histone subtype expression and chromatin structure in this distantly related echinoid closely resemble the euechinoids. The presence of an Sp H2B and a very long repeat length appear to be characteristic of the echinoids only.
Influence of intracellular pH on reduction of energy metabolism during hypoxia in the lugworm Arenicola marina
Authors: Juretschke Hans‐Paul , Kamp Günter
Published: June 2005

The influence of intracellular pH (pHi) on the energy metabolism during hypoxia was studied in the lugworm Arenicola marina using in vivo 31P nuclear magnetic resonance (NMR) spectroscopy and biochemical analysis of the metabolic end products during hypoxia. By addition of phenylphosphonic acid (PPA) to the incubation medium to increase the extracellular H+ buffering capacity, different degrees of intracellular acidosis during hypoxia could be attained.

At low extracellular PPA concentrations pHi dropped within 12 h of hypoxia from 7.3 to 6.7. High extracellular PPA concentrations (50 mM) kept pH1 stable at 7.2. Glycogenolysis was enhanced during hypoxia at high pHi, as shown by the measured amounts of accumulated end products. ATP production at high pHi was 31 μmol/g h vs. 15 at low pHi‐ The mobilisation of the phosphagen phosphotaurocyamine (PTC) was, in contrast, decreased at high pHi: the ratio PTC/β‐ATP dropped from 4.8 (normoxia) to 2.8 at high vs. 1.3 at low pHi. The reduction of the metabolic rate during hypoxia hence depends on intracellular acidosis: the rate of the Embden‐Meyerhof‐Parnas pathway at high pHi was 4.5 μmol/g h vs. 1.9 at low pHi.
Heat shock protein 70 gene expression in intact salamanders (Eurycea bislineata) in response to calibrated heat shocks and to high temperatures encountered in the field
Authors: Near Joseph C. , Easton Douglas P. , Rutledge Paul S. , Dickinson Douglas P. , Spotila James R.
Published: June 2005

Synthesis of heat shock proteins (hsps) is a universal response of cells to heat shock. Recent evidence suggests that hsps are involved in the repair of damage caused by heat or other protein‐denaturing insults. We have determined kinetics of induction for the 70 kD heat shock protein (hsp 70) and hsp 70 mRNA in adult salamanders, Eyrycea bislineata. We demonstrate that the extent of expression of the hsp protein and mRNA is proportional to the heat dose but differs with respect to tissue. Hsp 70 synthesis was shown to be controlled primarily at the level of mRNA transcription. Hsp 70 mRNA accumulation is prolonged in the adult animal when compared to cultured cells from other vertebrate ectotherms given similar heat shocks. Additionally, we show that the hottest of four animals captured in the field on a hot summer day had synthesized hsp 70 mRNA in its tissues. These findings are discussed relative to the thermal biology of vertebrate ectotherms.
Metabolic implications of Ldh‐B genotype during early development in Fundulus heteroclitus
Authors: Paynter Kennedy T. , DiMichele Leonard , Hand Steven C. , Powers Dennis A.
Published: June 2005

The metabolic rates of different Ldh‐B genotypes of developing Fundulus heteroclitus embryos were examined. Within 24 hours after fertilization, eggs homozygous for the southern (Ldh‐Ba) allele began to exhibit significantly higher oxygen consumption than eggs homozygous for the northern (Ldh‐Bb) allele. No significant differences existed between genotypes with respect to total LDH‐B4 activity or ontogeny throughout development. Lactate concentrations were significantly different in the oocytes between genotypes (Ldh‐Ba = 48 mM; Ldh‐Bb = 40 mM). Furthermore, lactate was utilized at a high rate during early development. Lactate utilization was approximately 100 times higher than apparent glucose utilization, and both rates were significantly different between genotypes. Within 24 hours after fertilization, half of the lactate present in the oocyte was utilized in both genotypes. Oxygen consumption and heat dissipation measurements demonstrated that the Ldh‐Ba homozygotes increased their metabolic rate dramatically between 10 and 15 hours after fertilization and that the Ldh‐Bb homozygotes did not. It is suggested that lactate is a source of intermediates important for early development and that LDH‐B4 may mediate the accumulation of that lactate in the oocyte and the utilization of lactate in the early development of the embryo. This metabolic role may lead to environmentally induced selection at the Ldh‐B locus.
Timing in the movement of jaws, tongue, and hyoid during feeding in the hyrax, Procavia syriacus
Authors: German Rebecca Z. , Franks Herschel A.
Published: June 2005

The anatomical structures used during mammalian feeding are morphologically linked by their connecting musculature, suggesting a predictable timing relationship among their movements. Cine‐x‐ray (100 frames per second) was used to record feeding behavior in four adult hyraxes (Procavia syriacus), herbivores. Movement of jaws, tongue, and hyoid bone was cyclic, and prior to the first swallow cycle, cycle duration was constant through time for all structures. Minimum gape, beginning of forward movement of the tongue and hyoid, and beginning of intrinsic tongue expansion occurred simultaneously over a large number of cycles. However, maximum gape, maximum protrusion of hyoid, and maximum forward position of the tongue happened at statistically different points in time. After the first swallow, cycle duration increased. Most of the variation in cycle duration can be explained by variation in the opening or forward phase of movement; the closing and return phases are constant in duration. These results are a quantitative description of the coordination that exists during different feeding behaviors (ingestion, intraoral transport, mastication, and swallowing) in normal, freely functioning hyraxes. The patterns of phase duration differ from some results obtained by using anesthetized animals.
Effects of 20‐hydroxyecdysone on protein synthesis in tissues of the land crab Gecarcinus lateralis
Authors: Paulson Charles R. , Skinner Dorothy M.
Published: June 2005

The endocrine regulation of molting was investigated in the crab Gecarcinus lateralis by treating tissues from anecdysial (intermolt) animals with the arthropod molting hormone 20‐hydroxyecdysone (20HE) in vitro and observing changes in the incorporation of [35S]‐methionine into proteins. Although total protein synthesis was not affected by levels of 20HE ranging from 10−9 to 10−5 M, synthesis of five out of 30 protein bands was significantly stimulated at hormone concentrations of 10−9−10−7 M, the latter characteristic of proecdysis. Increases were as large as eightfold. Synthesis was not significantly inhibited for any of the integumentary proteins. Treatment of integumentary tissues with 10−5 M 20HE (approx. 100 times greater than the highest endogenous concentration) had less effect than physiological concentrations. The dose response varied substantially among integumentary proteins. In some instances, the effects were similar to changes in synthesis that occur in vivo during specific stages of proecdysis (Stringfellow and Skinner, Dev. Biol., 128: 97–110, '88). Midgut gland (hepatopancreas) was also treated with 20HE in vitro. Treatment with 20HE significantly inhibited total protein synthesis in tissue from males, but not in that from females. This treatment inhibited the synthesis of a number of the 32 protein bands examined in both sexes. Synthesis of six protein bands was significantly inhibited in males, while synthesis of three different bands was significantly inhibited in females. This inhibitory action of 20HE is consistent with the atrophy of the midgut gland that occurs during proecdysis (Gibson and Barker, Oceanogr. Mar. Biol. Annu. Rev., 17: 285–346, 79).
Ontogenetic changes in fusibility in the colonial hydroid Hydractinia symbiolongicarpus
Authors: Shenk M. Andrew , Buss Leo W.
Published: June 2005

Invertebrate fusion and rejection responses are typically assumed to be mutually exclusive and temporally stable states. We here describe a segregant class appearing in an F1 cross of the colonial hydroid, Hydractinia symbiolongicarpus, that displays an ontogenetic change in fusibility. Reproductively immature offspring fuse to parental strains and have been observed to remain continuously fused for up to 76 days. By contrast, reproductively mature offspring initially fused with parental strains, only to separate into distinct colonies after a period of 3–21 days postfusion. Experimental manipulations demonstrate that (1) ontogenetic changes in fusibility cannot be removed by resetting a colony to a reproductively immature state, and (2) secondary contact does not result in an accelerated response.