bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tissue‐specific alanopine dehydrogenase and strombine dehydrogenase from the sea mouse, Aphrodite aculeata (polychaeta)
Authors: Storey Kenneth B. 
Published: June 2005

AbstractEach tissue of the sea mouse, Aphrodite aculeata, contains a single cytoplasmic dehydrogenase acting at the pyruvate branchpoint: Alanopine dehydrogenase (ADH) occurs in longitudinal muscle, nerve, and elytra, and strombine dehydrogenase (SDH) characterizes pharynx and intestine. Lactate and octopine dehydrogenases were not detected in any tissue. ADH from muscle and SDH from pharynx were partially purified. The two enzymes had the same molecular weight, 44,000 ± 4,000 but differed in isolelectric point. Although similar in keto acid specificity, the enzymes differed strongly in amino acid specificity. Pharynx SDH showed a very high specificity for glycine, all other alternative amino acids showing very high apparent Kms and/or low Vmaxs. Muscle ADH, however, displayed high velocities and relatively low apparent Kms with L‐alanine, L‐serine, L‐threonine, and L‐cysteine. Amino acid analysis of the tissues showed that serine and threonine contents were high enough in muscle to suggest that these amino acids might be alternative substrates to alanine in vivo; only glycine, present at 382 μmol/g in pharynx, is likely to be a physiological substrate for SDH, however. Absolute Kms for L‐alanine, glycine, and pyruvate were 2.75 ± 0.03, 285 ± 6, and 0.2 ± 0.006 for muscle ADH and 130 ± 2.2, 26 ± 1 and 0.15 ± 0.005 for pharynx SDH. In the reverse direction, apparent Kms for meso‐alanopine, D‐strombine, and NAD, at pH 9.5, were 1.68 ± 0.06, 87.0 (n = 1), and 0.75 ± 0.03 for ADH and 6.75 ± 0.20, 7.57 ± 0.07, and 0.54 ± 0.02 for SDH. The enzymes also differed strongly in effects of inhibitors. Meso‐alanopine, L‐lactate, and D‐lactate were strong inhibitors of the forward reaction for muscle ADH. Pharynx SDH, however, was strongly inhibited by meso‐alanopine and iminodiacetic acid but showed only weak inhibition by D‐ or L‐lactate or by its product, D‐strombine.
A histological and dynamic study of the gastric region of Discoglossus pictus larvae, cultured with or without thyroxine
Authors: Pouyet J. C. , Hourdry J. , Mesnard J. 
Published: June 2005

AbstractThe organotypic culture of the gastric region is carried out on premetamorphic Discoglossus pictus larvae. Adding thyroxine to the culture medium provokes various transformations. On the cytological level, the reactions observed, which are variable depending on the cell category concerned, can be divided into two types of phenomena: histolytic and histogenetic. Auto‐phagia linked to lysosome intervention is frequently found among the histolytic processes. Autophagic vacuoles and residual bodies are observed. The gastric lumen is filled with deteriorated cells that probably come from the degeneration of the tadpole epithelium (primary epithelium). The incorporation of tritiated thymidine makes it possible to study the evolution of cell proliferation in the control and in the thyroxinated cultures. After a 1–2 day latency period, possibly due to the adjustment of the tissue to the culture environment, the incorporation of the radioprecursor H3‐thymidine into the epithelium and the tunica muscularis of thyroxine‐treated gut tissue increased on day 3, reached a maximum on day 5, and then dropped slightly on day 7. In the control cultures H3‐thymidine incorporation showed the same pattern but lower levels on the same days. The histolytic phenomena induced by thyroxine in vitro are comparable to those of natural metamorphosis. On the other hand, the histogenetic phenomena are incomplete. Proliferating and transitional phases occur but neoformated (or secondary) epithelium does not replace the degenerated primary epithelium, whatever the culture time.
Studies on the mechanisms of neurulation in the chick: Possible involvement of myosin in elevation of neural folds
Authors: Lee Hsin‐Yi , Kosciuk Mary C. , Nagele Robert G. , Roisen Fred J. 
Published: June 2005

AbstractThe possible involvement of myosin in elevation of neural folds in the chick was studied. Indirect immunofluorescence revealed the presence of myosin in the neuroepithelium as early as the neural‐plate stage and was concentrated in the apical regions of neuroepithelial cells where microfilaments are known to be organized into discrete bundles. This fluorescent pattern persisted until closure of the neural tube. Actin‐specific fluorescence followed a similar distribution pattern as myosin. Diazepam (Valium/Roche), at 400 μg/ml, was found to preferentially inhibit elevation of neural folds in explanted stage 8 embryos within 6 hr of incubation. Affected neuroepithelial cells were often less elongated, contained thinner and less conspicuous microfilament bundles, and had apical surfaces which were smoother and broader than the controls. These morphological changes were accompanied by a considerable reduction in the intensity of myosin‐specific fluorescence, particularly in the cell apices. Results suggest that (1) diazepam inhibits elevation of neural folds through its disruptive effects on the organization and contractility of apical microfilament bundles in developing neuroepithelial cells and (2) myosin may be directly involved in elevation of neural folds.
Developmental arrest of endoparasitoid wasp larvae (Nemeritis canescens grav.) caused by an ectoparasitoid wasp (Bracon hebetor say)
Authors: Petters Robert M. , Stefanelli Joseph 
Published: June 2005

AbstractThe effect of Bracon hebetor‐induced host paralysis on the development of Nemeritis canescens was examined. These two wasp species were found to often coexist at the same location and can utilize the same host species. N. canescens females were allowed to oviposit into Anagasta kuehniella larvae. The parasitized host caterpillars were then exposed to B. hebetor females which paralyzed the caterpillars with a venom. Subsequent to host paralysis and removal of the B. hebetor females, host caterpillars were dissected daily to determine the developmental stage of the endoparasitoid N. canescens larvae. Virtually complete inhibition of development occurred when host paralysis was induced within 12 hours of N. canescens oviposition although larval movement and morphology were normal. Developmental inhibition also took place when host paralysis was induced 1 week after oviposition but it required a few days to become evident. The possible mechanisms of developmental arrest are discussed.
Adhesion of mouse blastocysts to uterine epithelium in culture: A requirement for mutual surface interactions
Authors: Morris John E. , Potter Sandra W. , Rynd Lori S. , Buckley Patricia M. 
Published: June 2005

AbstractBlastocysts readily adhered to inert materials in culture, but they resisted adhesion to living cells even after several days under conditions which encouraged cell aggregation. As far as could be determined by observing their spreading behavior on polylysine‐ and polyglutamate‐coated dishes, the mechanism of adhesion of blastocysts to inert surfaces was similar to that of freshly dissociated cells and cell lines. However, their adhesion to vesicles of isolated uterine epithelium, which was encouraged by hanging drop culture, was by a different mechanism that involved microvilli on both the embryonic and maternal surfaces. This interactive step, which was similar to that seen during attachment in vivo, was followed by a brief period of close trophoblast‐epithelial contact which led ultimately to phagocytosis of sloughed epithelium. Blastocysts showed a clear preference for adhesion to cultured epithelium in vesicles that had begun to collapse. In this case the cells showed a columnar profile with sharply defined microvillous apexes, unlike the flattened cells in fully expanded vesicles or on culture dishes. We conclude that the preimplantation adhesion of mouse blastocysts requires specific changes on both the embryonic and maternal surfaces to overcome the mutual nonadhesiveness typical of epithelia. The relatively rapid adhesion of blastocysts to a culture dish, on the other hand, is more typical of the well‐known spreading behavior of cells on a highly attractive surface.
Determination of the rate of rRNA synthesis in Xenopus laevis triploid embryos produced by low‐temperature treatment
Authors: Tashiro K. , Misumi Y. , Shiokawa K. , Yamana K. 
Published: June 2005

AbstractTriploid embryos of Xenopus laevis were obtained by cold‐temperature shocking of the fertilized eggs, and the rate of the ribosonial RNA (rRNA) synthesis was determined for comparison with that in diploid embryos. For this purpose, both triploid and diploid embryos were dissociated into cells at the neu‐rula stage, and then labeled with (3H)uridine for varying lengths of time. The rate of rRNA synthesis, as estimated after determination of (3H)UTP specific radioactivity and the total label incorporation into the purified rRNA, was about 0.1 pg/cell/hr for both diploid and triploid embryo cells.Nuclei of triploid embryo cells contained three nucleoli of apparently similar sizes—an indication of the functioning of all the three rRNA gene clusters to a more or less similar extent. Also, rates of synthesis of 4S RNA and 5S RNA were determined: Both rates did not change appreciably between triploid and diploid embryo cells. Based on these results, it appears that transcription of these redundant genes occurs at a constant rate on a per cell basis irrespective of the presence of 1.5 times as many genes as the control.
Localization of actin in the sperm head of the plains mouse, Pseudomys australis
Authors: Flaherty Sean P. , Breed William G. , Sarafis V. 
Published: June 2005

AbstractActin was localized in the sperm head of the plains mouse, Pseudomys australis, using NBD‐phallacidin, a fluorescent‐labeled phallotoxin. It was found to be present in the two ventral hooks in sperm from the testis, epididymis, and vas deferens. Faint fluorescence was observed in other regions of the sperm head, whereas autofluorescence occurred in the midpiece of the tail in some preparations. The material in the ventral hooks was also found to be birefringent, which is consistent with it showing preferential orientation.
Evidence that the ciliate Euplotes raikovi releases mating inducing factors (gamones)
Authors: Luporini Pierangelo , Miceli Cristina , Ortenzi Claudio 
Published: June 2005

AbstractEight mating type complementary strains of E. raikovi were mixed two by two in all the possible combinations. In addition to heterotypic pairs, homotypic pairs of both mixed strains were usually found. Each strain was then suspended with the cell‐free fluid obtained from any other complementary strain. Most strains appeared capable of both producing an active cell‐free fluid and responding to a heterotypic cell‐free fluid by pairing. The induced pairs were usually able to complete conjugation, to survive, and to yield viable offspring. The results indicate that mating inducing factors (gamones) are normally released into the extracellular environment by the E. raikovi cells.
Oxygen consumption and whole body lactate accumulation during progressive hypoxia in the tropical freshwater prawn,Macrobrachium rosenbergii(de Man)
Authors: Spotts Daniel G. 
Published: June 2005

AbstractDaytime and nighttime rates of oxygen consumption (VO2) were determined for young freshwater prawns during progressive hypoxia. During daytime hypoxia VO2fell slightly, then was maintained at 0.200 ml O2/gm/h to 40 mm Hg partial pressure of oxygen. Below 40 mm Hg VO2fell markedly. At night VO2averaged 0.310 ml O2/gm/h before falling at a critical pressure (Pcr) of 65 mm Hg. Sets of prawns were exposed to progressive hypoxia both day and night at rates simulating conditions during the closed respirometry studies. Prawns were sacrificed at different PO2s and analyzed for whole body lactate concentrations. Concentrations of 0.153 mg lactate/gm body weight were unchanged until the respective Pcrwas reached during either day or night. Below Pcrlactate concentrations increased at a constant rate regardless of the severity of hypoxia. Combined aerobic metabolism and anaerobic glycolysis did not increase as a result of progressive hypoxia, indicating a small energy requirement for oxyregulation. Anaerobic energy production via glycolysis during hypoxia proceeded at only 1–3% of the regulated aerobic metabolism. This is much less than in other crustaceans, underscoring the importance of well‐aerated environments both inMachrobrachium rosenbergii'snatural habitat and under aquaculture conditions.
Increased amino acid oxidation in the gills of blue crabs acclimated to dilute seawater
Authors: Pressley Thomas A. , Graves James S. 
Published: June 2005

AbstractSubstrate oxidation was measured in the gills of blue crabs, Callinectes sapidus, acclimated to different salinities. The oxidation rates for glucose and the four major amino acids of hemolymph were about twice as great in the gills from crabs acclimated to 17%0 seawater relative to the gills from crabs acclimated to full‐strength, 35%0 seawater. Alanine oxidation contributed about 36% to the total CO2 released from amino acid oxidation. Alanine was also deaminated and released into the medium as α‐keto acids. Both alanine oxidation and α‐keto acid formation were concentration dependent and did not appear to reach saturation within physiological concentrations. However, the rates of amino acid oxidation were not sufficient to explain the efflux of NH4+ in excised gills.
Contractions of amphibian Wolffian duct in response to acetylcholine, norepinephrine, and arginine vasotocin
Authors: Zoeller R. Thomas , Lais L. Terry , Moore Frank L. 
Published: June 2005

AbstractThe regulation of sperm transport through the Wolffian duct of male amphibians is poorly understood. These experiments were conducted using rough‐skinned newts (Taricha granulosa) to determine if Wolffian ducts are capable of contracting in vitro and, if so, to characterize the contractile responses to acetylcholine (ACh), norepinephrine (NE), and neurohypophysial hormones. Dose‐response curves for NE and ACh, which were prepared by measuring isometric contractions, are similar to those reported for mammalian vas deferens. For NE, the minimum effective dose and ED50 were found to be 1 × 10−5 M and 4.17 × 10 −5 M, respectively. For ACh, the minimum effective dose was 3.2 × 10−8 M and the ED50 was 1.37 × 10−5 M. Alpha‐adrenorecep‐tors appear to mediate the contractile responses to NE because phentolamine (10 −5 M) blocked or attenuated the response to NE (10−6 M, 10−5 M or 10−4 M). Beta‐adrenoreceptors appear to mediate relaxation because dichloroisoproterenol (10 −5 M) enhanced the response to 10−5 M NE. The contractile response to three neurohypophysial hormones were also investigated. Arginine vasotocin was more effective in eliciting contractions than oxytocin. The effect of lysine vasopressin was intermediate between arginine vasotocin and oxytocin. These experiments demonstrate that amphibian (Taricha) Wolffian ducts contract in vitro in response to neurotransmitters and neurohypophysial hormones. The contractile response to neurotransmitters occurs in a dose‐dependent manner; the response to neurotransmitters and neurohypophysial hormones is hormone specific.
Hatching in the teleost Oryzias latipes: Limited proteolysis causes egg envelope swelling
Authors: Schoots Andréa F. M. , Sackers Ruud J. , Overkamp Perry S. G. , Denucé J. Manuel 
Published: June 2005

AbstractHomogenates of hatching gland explants were fractionated by means of different electrophoretic techniques, and the fractions analyzed for proteolytic activity and for their capacity to affect the envelope of the eggs. Agar gel electrophoresis resulted in two fractions that were able to digest the zona radiata interna, and a third fraction that caused a significant swelling of the egg envelope. All three fractions were proteolytically active. Agarose gel and polyacrylamide gel electrophoresis gave only two fractions that showed proteolytic activity and were capable of digesting the zona radiata interna. The presence of these two fractions may imply that hatching enzyme is stored as proenzyme in the hatching gland granules. Swelling of egg envelopes was also observed during envelope digestion by thermolysin, pronase, and 0.5–1.0 N NaOH. Moreover, breakdown by hatching enzyme and pepsin under suboptimal conditions showed a slight swelling of the envelope. These results demonstrate that substances capable of solubilizing the zona radiata interna may cause envelope swelling. The swelling of the envelopes probably represents an intermediate phase in the proteolysis of the zona radiata interna. The agar gel electrophoresis fraction of hatching gland homogenates that causes swelling may contain a physicochemically different form of hatching enzyme.
Syntheses of nucleic acids during spermatogenesis in Nereis diversicolor (Annelida Polychaeta): A quantitative autoradiographic study
Authors: Bertout Marc 
Published: June 2005

AbstractThe development of DNA and RNA synthesis in the germ cell population was studied after a 3H‐thymidine or 3H‐uridine pulse at each stage of spermatogenesis. The autoradiographic results show that the first sign (after 3 days in vitro) of cellular changes is an increase in RNA synthesis which reaches a maximum at day 5. DNA replication (premeiotic S phase) occurred at day 7, then cells entered meiotic prophase (day 9). Meiotic divisions and spermiogenesis occurred after 11 days. Silver grain counts permit the conclusion that RNA synthesis is clearly higher during premeiotic interphase (days 3–7) than during spermatogonial proliferation (day 0). It appears therefore that male meiotic differentiation in Nereidae is accompanied by increased RNA synthesis.
Carbonic anhydrase localization in the elasmobranch rectal gland
Authors: Lacy Eric R. 
Published: June 2005

AbstractCarbonic anhydrase (CA) activity was histochemically localized in the elasmobranch rectal gland at the light and electron microscopic levels. Reaction product in the secretory tubules was localized coincident with that reported for sodium‐potassium activated adenosine triphosphatase (Na‐KATPase): along the highly amplified basolateral plasma membranes of the epithelial cells. Reaction product was also localized along the plasma membrane of adjacent central canal epithelial cells. The results suggest that CA plays a role in modulating the environment of the intercellular space which in the secretory tubule is believed to be the paracellular pathway for sodium. The results also draw attention to the possible role of the central canal epithelium in modification of the secreted fluid.
Thermoperiodic and photoperiodic influences on daily and seasonal changes in the physiology of the male green anole, Anolis carolinensis
Authors: Noeske Teresa A. , Meier Albert H. 
Published: June 2005

AbstractMale green anole lizards, Anolis carolinensis, were kept for 22 days on one of five temperature regimes: constant 20°C, constant 30°C, or a thermoperiod (8 h at 30°C, 16 h at 20°C) with heat onset at 0, 8, or 16 h after light onset. Groups of animals on each temperature regime were sacrificed at one of six times of day, every 4 h, for 24 h. The experiment was repeated at three different times of year: April (animals were kept on a photoperiod of LD 13:11), August (LD 13.5:10.5), and December (LD 10.5:13.5). Weight gain, testes weights, reproductive stage, and abdominal fat body weights varied with the temperature treatment and with the season. Depending on the time of day lizards received the warm temperature phase of the thermoperiod, increased heat could be stimulatory to weight gain and reproductive indexes in comparison to heat treatment at other times of day. The effect of constant temperatures on testis state and body weight gain was different from that of the thermoperiod regimes and of the natural environment on these processes.There were also diel variations in both testis DNA synthesis and fat body lipogenesis in the green anole. The photoperiod appeared to set the daily variation of DNA synthesis in the testis, whereas the thermoperiod phased the daily variation of fat body lipogenesis.
Characterization of molluscan phagocyte subpopulations based on lysosomal enzyme markers
Authors: Granath Willard O. , Yoshino Timothy P. 
Published: June 2005

AbstractThis study quantitatively analyzed the distribution and abundance of the lysosomal enzyme markers, acid phosphatase (AP), nonspecific esterase (NE), and peroxidase (PO) within and between the phagocytes (hemocytes) of two strains of the snail, Biomphalaria. Glabrata, vector host for the human blood fluke, Schistosoma mansoni. Discrete subpopulations of AP‐, NE‐, and PO‐staining cells were found in the glass‐adherent hemocyte population of both schistosome‐resistant (10‐R2) and susceptible (PR albino) strains of the snail. Furthermore, there were significant differences in the distribution and abundance of the different enzymes defining the subpopulations within and between the snail strains. Generally, 10‐R2 hemocytes have a higher enzymatic activity than PR albino cells, which, in part, can be attributed to larger NE‐only, AP‐only, and AP + NE‐staining hemocytes in the 10‐R2 strain, and a larger subpopulation of negative cells in PR albino snails. Moreover, these differences in hemocyte enzyme content are further augmented by the fact that the 10‐R2 strain has nearly twice as many circulating, glass‐adherent blood cells when compared to PR albino snails. These findings may be of additional significance, since previous studies have implicated hemocyte lysosomal enzymes in the killing of schistosome larvae in naturally resistant 10‐R2 snails, although accurate measurements of strain‐specific enzyme levels in these cells have not been conducted. The present study provides direct evidence that 10‐R2 snails naturally possess a much greater lysosomal enzyme content than do those of the PR albino strain, which, in turn, may be related to the observed resistance or susceptibility in these two molluscan strains.
Vitellogenic cycles in laboratory‐maintained females of the leopard frog, Rana pipiens
Authors: Smalley Katherine N. , Nace George W. 
Published: June 2005

AbstractAs a part of studies on the reproduction of laboratory maintained frogs, wild‐caught Rana pipiens were ovulated and maintained a t 22–27°C for up to 18 months. Vitellogenic oocytes were periodically staged and counted, and a “maturity index” was calculated to assess the progress of the vitellogenic cycle. The initial cycle was similar to that of wild frogs except that the first oocytes to reach stage 5 (mature eggs) usually began to degenerate before later starting oocytes became mature. In addition, a second cycle began before the first was completed. After more than 1 year at room temperature, abnormal cycles were common. Ovaries of such animals contained very few mature eggs. Many of their oocytes were in early stages of vitellogenesis or, if pigmented, had begun to degenerate. These deficiencies were partially corrected in females placed in 4°C for 4–6 weeks. The average number of mature eggs increased 15‐fold and ovary weights more than doubled. Oviduct weights almost doubled. Although the rates of cooling, photoperiod, and nutritional status could be important influences, the results imply that cold treatment alone increases estrogen secretion. We suggest that low estrogen secretion may account for the reproductive deficiencies seen in R. pipiens cultured at room temperature.