bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assimilation and deposition of dietary fatty alcohols in Leach's storm petrel,Oceanodroma leucorhoa
Authors: Place Allen R. , Roby Daniel D. 
Published: June 2005

AbstractThe diet of Leach's storm petrel (Oceanodroma leucorhoa) chicks has a high lipid content (up to 60% of fresh mass), and, for certain populations, much of the dietary lipids are wax esters (up to 70% of total lipid). In order to determine the metabolic fate of dietary wax esters, we fed chicks [1‐14C]cetyl oleate in either a low wax (20%, w/w) or a high wax (80%, w/w) mixture of wax ester and triacylglycerols. Wax ester in the stomach remained unhydrolyzed for extended periods, with up to 38% of the label still unassimilated after 36 hr. Hydrolysis occured principally in the duodenum, where the fatty alcohol product was rapidly oxidized to fatty acid, apparently at the intestinal epithelia. Assimilated label was primarily metabolized and respired as carbon dioxide, with most of the remainder incorporated into triacylglycerols and deposited in storage fat depots. Hydrolysis of wax ester and assimilation of the fatty alcohol moiety were extremely efficient, with less than 0.2% of ingested label excreted. Assimilation efficiencies for label in low wax and high wax meals were statistically indistinguishable. Chicks fed 20% (w/w) [1‐14C]cetyl alcohol in triacylglycerols had similar assimilation efficiencies as those fed labeled wax ester, indicating that hydrolysis of the ester linkage does not limit wax ester assimilation. This study suggests that sea birds can possess an efficient means for metabolizing wax esters, an abundant energy source in the marine environment, which have previously been thought to be difficult to assimilate.
Neoplastic transformation in the planarian: II. Ultrastructure of malignant reticuloma
Authors: Hall Frederick , Morita Michio , Best Jay Boyd 
Published: June 2005

AbstractCadmium and phorbol ester induced tumorigenesis in the planarian, Dugesia dorotocephala, develops as a cocarcinogenic process involving initiation and promotion in the progression of neoplastic disease. Treatment of intact planarians with sublethal concentrations of cadmium sulfate and 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) induced a type of infiltrating tumor that proved to be potentially lethal. Surgical transplantation of such tumorous tissues into otherwise healthy planarians resulted in the same histopathological progression to lethality, which confirmed the metastatic nature of the neoplasia. Electron microscopic studies revealed that both the chemically‐induced and the transplantation‐based tumors involved, exclusively, the proliferation and differentiation of abnormal reticular cells, referred to as reticuloma cells. Reticular cells normally are ameboid, phagocytic, and are thought to provide the planarian with a phylogenetic predecessor of an immune surveillance system. A considerable incidence of mitosis was observed within the tumor areas; and the sequence of differentiation, from transformed stem cells to mature but nonfunctional reticuloma cells, was elucidated. This profile of differentiation supports the concept of cellular derivation via stem cell dynamics as opposed to dedifferentiation. A variety of ultrastructural abnormalities were characterized: several of which tend to substantiate the anaplastic quality of the reticuloma, while others are more specifically diagnostic for malignancy. These findings further extend the potential usefulness of the planarian malignant reticuloma as a model system for the study of neoplastic stem cell diseases.
Differences between early‐ and late‐maturing genotypes of the platyfish (Xiphophorus maculatus) in the morphometry of their immunoreactive luteinizing hormone releasing hormone‐containing cells: A developmental study
Authors: Halpern‐Sebold Leslie R. , Schreibman Martin P. , Margolis‐Nunno Henrietta 
Published: June 2005

AbstractImmunoreactive luteinizing hormone releasing hormone (ir‐LHRH) containing perikarya, brain nuclei, and pituitary cells were studied during the postnatal development of male sibling platyfish (Xiphophorus maculatus) genetically determined to reach puberty at two different ages using immunocytochemical, cytological, and morphometric methods. Ir‐LHRH‐containing perikarya first appear in the nucleus olfactoretinalis (NOR) at 5 weeks of age in early maturers and at 11 weeks in late maturers at a maximum number which is similar in both genotypes and remains constant into adulthood. The dimensions of the NOR and its perikarya increase up to the initiation of sexual maturation (gonopodial stage 2) in both genotypes. In the nucleus preopticus periventricularis (NPP), ir‐perikarya appear at stage 2 and are maximum in number at maturity (stage 6) when early maturers have 50% more than late maturers. Measurements for the NPP increase between 1 week and stage 6 in both genotypes. In the nucleus lateralis tuberis (NLT), irperikarya appear soon after stage 2 in early maturers but are never seen in late maturers. Late maturers also have fewer ir‐LHRH containing pituitary cells than early maturers. In both genotypes, measurements for the NLT increase to stage 2 and then decrease to stage 6.During sexual development there are differences between early‐ and late‐maturing genotypes in the morphometry of their LHRH‐containing brain centers. The timing of sexual development creates significant differences in the cytological and cytometric characteristics of the three ir‐LHRH‐containing brain nuclei in fish of the same age but different genotype. Our results also show that for both genotypes there is a positive correlation between the total number of ir‐LHRH brain neurons and the total number of ir‐pituitary cells and both are lower for late maturers at every age and stage.
Integumentary uptake of acetate and propionate (VFA) by Tubifex sp., a freshwater oligochaete. I. Uptake rates and transport kinetics
Authors: Hipp Erich , Mustafa Tariq , Bickel Ursula , Hoffmann Klaus H. 
Published: June 2005

AbstractThe freshwater oligochaete Tubifex tubifex can achieve an uptake of short‐chain volatile fatty acids (VFA; acetate and propionate) from artificial tap water at naturally occurring interstitial concentrations of 5 to 1000 μM. The uptake results from a combination of saturable and nonsaturable transport, the former displaying Michaelis‐Menten‐type kinetics. The saturable component is susceptible to inhibition by structurally analogous substances. The kinetics of the inhibition were found to be competitive. VFA uptake rates are strongly depressed by potassium cyanide and iodoacetate. Furthermore, VFA uptake is susceptible to inhibition by ouabain and to Na+ depletion. Q10 values in excess of two are also consistent with the suggestion that a mediated system for VFA absorption exists in the integument of T. tubifex.
Loss of seawater preference in chum salmon (Oncorhynchus keta) fry retained in fresh water after migration season
Authors: Iwata Munehico , Ogura Hiroyuki , Komatsu Shichiko , Suzuki Keiji 
Published: June 2005

AbstractSalinity preference of chum salmon fry (Oncorhynchus keta) was measured by the use of a preference tank. In April, when they normally migrate down to the sea, freshwater chum fry weighing about 0.6 g preferred seawater diluted 1:2 with fresh water (11 parts per thousand in salinity) and seawater over fresh water. Chum fry acclimated to the diluted seawater for 1 day preferred seawater over fresh water. In May, however, freshwater fry preferred only diluted seawater. Furthermore, the preference for seawater of freshwater fry, and of fry that had become acclimated to diluted seawater, decreased significantly. Plasma levels of sodium ions in freshwater fish were 138–142 mmol/L in April and May. When the fish were transfered to diluted seawater in April and May, the levels of sodium ions increased gradually over 6 hours to the level in seawater‐acclimated fish, namely 153–155 mmol/L. Plasma levels of sodium ions in fry acclimated to diluted seawater did not change after exposure to seawater. In freshwater fry that were exposed to seawater, the maximum concentration in plasma of sodium ions was 165 mmol/L in April and 177 mmol/L in May. The preference of fry acclimated to seawater or to diluted seawater was also examined in April and May. More than 70% of fry that had acclimated to seawater showed a preference for diluted seawater and no preference for fresh water was noted in either the fry acclimated to seawater or to diluted seawater. Thus, for chum fry, the preference for seawater, as well as their adaptability to seawater, is maximal in April, during the migration period. No preference for fresh water was observed at any stage.
Factors regulating carbohydrate and lipid metabolism isolated from the corpus cardiacum of the Eastern lubber grasshopper, Romalea microptera
Authors: Spring Jeffrey H. , Gäde Gerd 
Published: June 2005

AbstractRomalea microptera corpus cardiacum (RCC) contains large quantities of peptide material that is capable of eliciting strong hyperlipemic (maximum increase, 26 mg/ml; locusts) and hypertrehalosemic (maximum increase, 27 mg/ml; cockroaches) responses in test species. Calculation indicate that RCC contain more than an order of magnitude more bioactive material than either Locusta or Periplaneta corpus cardiacum. R. microptera itself shows no response to injections of synthetic locust adipokinetic hormone I (AKH I) at doses of up to 100 pmol, although injection of RCC at high concentrations (up to 1.0 gland‐equivalents) causes moderate hyperlipemia (maximum increase, 3 mg/ml). Starved R. microptera do not exhibit the metabolic hyperlipemia observed in starved L. migratoria, but starvation does block the RCC‐stimulated hyperlipemia. Neither fed nor starved R. microptera show a hypertrehalosemic response to RCC or AKH I. Reversed‐phase high‐performance liquid chromatography (RP–HPLC) shows the adipokinetic/hypertrehalosemic bioactivity to be concentrated in two peaks, which are present in the ratio of 6:1 Peak I: Peak II. Further RP–HPLC studies suggest that Peak II is identical to the adipokinetic hormone from the cricket Gryllus bimaculatus, while Peak I appears to be a previously unknown neuropeptide.
Immunohistochemical study of calmodulin in developing mouse testis
Authors: Sano Mamoru , Ohshima Akiko‐Seto , Kawamura Noriko , Kitajima Satoko , Mizutani Akira 
Published: June 2005

AbstractThe purpose of this study was to determine the localization of calmodulin in the developing mouse testis by the indirect immunoperoxidase method. In addition, the amount of calmodulin in pachytene spermatocytes, spermatids, and residual bodies isolated from the mouse testis and epididymal spermatozoa was quantitated by the adenylate cyclase activation assay and by enzyme immunoassay. The relative levels of calmodulin in the developing mouse testis and in the isolated testicular germ cells were confirmed by western transfer staining. The level of immunoreactive calmodulin was very low in the testes from immature animals. In testes from the mature mouse, calmodulin was found to be localized in spermatocytes and spermatids, but was not found in spermatogonia, Sertoli cells, and interstitial cells. By contrast, immunochemical staining of tubulin was extremely intense in Sertoli cells. Biochemical determinations also showed that pachytene spermatocytes, round spermatids, spermatozoa, and residual bodies contained 14.9μg, 15.8μg, 2.3μg and 5.2μg of calmodulin per mg of protein, respectively. Both the immunochemical and the biochemical studies revealed that levels of calmodulin were high in the spermatocytes and in the round spermatids, as compared to the level in spermatozoa. This fact strongly suggests that the large amount of calmodulin in mammalian testes may be associated primarily with meiotic divisions and/or spermatogenesis.
Induction and inhibition of in vitro oocyte maturation and production of steroids in fish follicles by forskolin
Authors: Iwamatsu T. , Takahashi S. Y. , Sakai N. , Nagahama Y. , Onitake K. 
Published: June 2005

AbstractThe effects of forskolin (FK) on in vitro oocyte maturation and production of steroids were examined in Oryzias latipes. When oocytes within preovulatory follicles were preincubated in the presence of FK for 2–10 hr, they matured normally after additional incubation for 10–20 hr in plain culture medium. Naked (follicle cell‐free) oocytes did not mature under these conditions. FK stimulated dose‐dependent production of steroids (estradiol‐17β, E2, and 17α,20β‐dihydroxy‐4‐pregnen‐3‐one, 17α,20β‐diOHprog) and cAMP in follicle (granulosa) cells. On the other hand, exposure to FK within 2 hr after 17α,20β‐diOH prog stimulation caused reversible inhibition of gonadotropin (PMS)‐ or 17α,20β‐diOH prog‐induced maturation of the intrafollicular oocytes in vitro. FK also significantly inhibited the 17α,20β‐diOHprog‐induced maturation of naked oocytes, suggesting the existence of adenylate cyclase in fish oocytes. These data indicate that in Oryzias latipes, FK induces oocyte maturation by stimulating follicular production of maturation‐inducing steroid (MIS), probably 17α,20β‐diOH prog, via an increase in cAMP, and that it may inhibit oocyte maturation by increasing ooplasmic cAMP and some inhibitory interaction between the granulosa cells and the oocyte through intercellular communication.
Active ureogenesis in a freshwater air‐breathing teleost, Heteropneustes fossilis
Authors: Saha N. , Ratha B. K. 
Published: June 2005

AbstractActivities of all the enzymes of ornithine‐urea (o‐u) cycle and uricolytic pathway were assayed in different tissues of a freshwater air‐breathing teleost, Heteropneustes fossilis. High activity of all o‐u cycle enzymes as observed in the liver and kidney, were comparable to those of actively ureogenic fishes and amphibians. All the three enzymes of uricolytic pathway were found only in liver tissue. These observations strengthen an earlier suggestion made that active ureogenesis did exist in some freshwater teleosts such as H. fossilis. Presence of an active o‐u cycle in H. fossilis indicates that this fish is either relatively primitive to the purely aquatic freshwater teleosts retaining the ancestral character of a functional o‐u cycle or the genes for the synthesis of o‐u cycle enzymes might have been derepressed as a secondary modification for its adaptation to temporary dehydration or hyper‐ammonia environment.
Effects of catecholamines on early development of the chick embryo: Relationship to effects of calcium and cAMP
Authors: Sarasa Manuel , Climent Salvador 
Published: June 2005

AbstractCatecholamines (dopamine or norepinephrine) injected under the blastoderm of the unincubated chick embryo produced a thickened primitive streak and prevented the migration of axial mesoblast after 24 h. The mesoblastic cells that accumulated in the primitive streak contained many intracytoplasmic yolk granules. After 48 h, neural tube, notochord, and somites were severely affected, and their cells appeared loaded with yolk inclusions. Heart, lateral plates, blood cells, and blood vessels differentiated normally. At the onset of gastrulation, the level of glycogen was fivefold lower in catecholamine‐treated embryos than in control embryos. Injection of glucose plus dopamine, at equimolar concentrations resulted in normal development both at 24 h and at 48 h. Because adrenegic stimulation of glycogenolysis in differentiated cells is usually mediated by cAMP and/or by calcium, we attempted to determine whether these substances could reproduce the effects of catecholamines. Only calcium was able to produce, to a limited extent, the same morphogenetic disturbances as those produced by catecholamines, whereas the chelating agent, ethylenediamine tetraacetic acid, when administered with dopamine, partially inhibited the effects of catecholamines. An increase in the number of yolk granules was the only common finding among embryos treated with cAMP and catecholamines. Blood and a well differentiated, gastrular endoderm always developed, independently of the nature of the substance with which the embryos had been treated. Morphogenetic disturbances caused by exogenous catecholamines could be due to depletion of glucose. Alternatively, a different metabolic commitment might exist within the diverse populations of cells that constitute the mesoblastic layer.
Hormonal regulation of myoblast proliferation and myotube production in vivo: Influence of prostaglandins
Authors: McLennan Ian S. 
Published: June 2005

AbstractThe study of myoblast proliferation and fusion to form myotubes in vivo has centered around the role of the innervating motoneurones. Hormonal factors such as prostaglandin E1 (PGE1) are important during in vitro myogenesis, but their role in vivo has yet to be elucidated. In vitro, PGE1 appears to switch myoblast from a mitotic to a fusion mode. Consistent with this hypothesis, administration of PGE1 to chicken embryos decreased the number of myonuclei incorporated into their muscles. The effect of inhibitors of prostaglandin synthesis (aspirin and indomethacin) on in vivo myogenesis was not, however, as expected. Both drugs decreased the number of myonuclei incorporated into the muscles of treated embryos, which is the opposite of what would have been expected if they were enabling myoblasts to undergo additional divisions by delaying their onset from the mitotic cycle. The simplest explanation of this observation is that the effect of aspirin and indomethacin is mediated by a prostaglandin other than E1, or by a systemic factor whose levels are regulated by a prostaglandin. The maximum extent of the reduction caused by PGE1 and the inhibitors of prostaglandin synthesis was only 25–30%, suggesting that only a subpopulation of myoblasts is effected by these drugs. The number of myotubes formed in the treated embryos closely paralleled the total number of myonuclei, indicating that the number of myoblasts fusing to form a myotube is constant even when the total number of available myoblasts is diminished.
Discrimination of male conspecific from male heterospecific odors by male scincid lizards (Eumeces laticeps)
Authors: Cooper William E. , Garstka William R. 
Published: June 2005

AbstractMale broad‐headed skinks, Eumeces laticeps, were tested for the ability to discriminate the odors of conspecific males from those of males of the broadly sympatric and closely related E. fasciatus, which is similar in appearance. Tongue‐flicks elicited in 1 min by male cloacal odors of both species presented to 28 males in counterbalanced order. Data were analyzed by one‐way analysis of variance (ANOVA) for a repeated measures design. Male E. laticeps had significantly higher tongue‐flick rates when responding to conspecific male odors than to odors of male E. fasciatus. The adaptive advantage of interspecific discrimination of male odors may be recognition of sexual rivals or avoidance of injury incurred during interspecific fighting.
Cortical granules products and fertility prevention in Bufo arenarum oocytes
Authors: Cabada Marcelo O. , Mariano Marta I. , Gómez Marta I. 
Published: June 2005

AbstractA description of some properties of the cortical granule products (CGP) is provided. After activation, cortical granules (CG) discharge their content to the perivitelline space where most of these products remain. Two types of CGP preparations were used: one obtained by activating oocytes deprived of their vitelline envelope (tCGP), and the other obtained by activating oocytes covered by the vitelline envelope (vCGP). Both types of CGP were similar as regarding their capacity to modify oocyte sensitivity to spermatolysin. CGP modify the vitelline envelope (VE) of unactivated dejellied oocytes, which becomes insensitive to spermatolysin. This activity depends on both CGP concentration in the incubation media and the length of the incubation period. Once the effect of CGP on the oocyte is established it can not be completely eliminated by extensive washings, suggesting a lectin‐type association with the componenets of the VE. Treatment of dejellied oocytes with CGP results in fertility loss. The biological activity of CGP is related to thermolabile and nondialyzable substances. Lytic activity of spermatolysin on isolated VE is inhibited by CGP at a concentration at which trypsin inhibitors from soybean, lima bean, and ovomucoid are ineffective. The electrophoretic pattern of CGP indicates that most of the proteins present in the vCGP are derived from the VE. Ultrastructural modifications are observed in dejellied deposed oocytes after incubation with CGP.
Photoperiodic modulation of cephalic melatonin in planarians
Authors: Morita Michio , Hall Frederick , Best Jay Boyd , Gern William 
Published: June 2005

AbstractEndogenous melatonin was detected by high‐performance liquid chromatography (HPLC) with electrochemical detection (EC) in the head of the planarian Dugesia dorotocephala. The identity of this elution peak was further confirmed by radioimmunoassay. In groups of planarians adapted to either normal or reversed photoperiods, the melatonin levels were always higher in those heads collected in the dark period than in those collected in the light period. This indicates that primitive animals such as planarians have already evolved a melatonin‐metabolizing system that is photically driven in a manner suggestive of the way melatonin synthesis is influenced by light and dark cycles in vertebrates.
Assay and subcellular localization of H2O2 generating mannitol oxidase in the terrestrial slug Arion ater
Authors: Malik Zulfiqar , Jones Carolyn J. P. , Connock Martin J. 
Published: June 2005

AbstractAn assay is described that allows the measurement of H2O2‐generating mannitol oxidase activity in sucrose‐containing homogenates and subcellular fractions. Using this assay high activity was found in digestive gland and crop of the slug Arion ater. The subcellular localization of mannitol oxidase in these tissues was examined using sucrose density gradient centrifugation in a B‐XIV zonal rotor. Mannitol oxidase was found to reside in a lowdensity membrane tentatively identified as golgi or plasma membrane, rather than in mitochondria or peroxisomes as had previously been supposed.
Adenohypophysial‐thyroid activity of the tiger salamander, Ambystoma tigrinum, as a function of metamorphosis and captivity
Authors: Norman Mark F. , Carr James A. , Norris David O. 
Published: June 2005

AbstractThe aim of this study was to determine the timing of adeno‐hypophysial activation during metamorphosis of the tiger salamander, Ambystoma tigrinum. It consisted of two parts: (1) determination of plasma thyroid hormone concentrations and analysis of thyroid gland histology as a function of metamorphic stage and (2) analysis of the time‐course of uptake of 125I by the thyroids during metamorphosis as an indicator of endogenous thyrotropin (TSH) levels. Significant increases in both triiodothyronine (T3) and thyroxine (T4) first were evident at the onset of metamorphic climax (stage II). Maximum levels of both hormones were not observed, however, until the completion of gill resorption (stage VII). No changes in thyroid histology were observed that could be unambiguously related to metamorphic transformation. The thyroids accumulated 125I in a slow but linear fashion in premetamorphic larvae (stage I). However, uptake exhibited a rapid peak during early climax (stage II), before maximum concentrations of thyroid hormones were observed. In addition, uptake was maintained above premetamorphic levels at stage VII, in conjunction with maximum levels of T4 and T3. Captivity alone produced a small but significant increase in plasma concentrations of T3. It produced no significant effect on either thyroid histology or uptake of 125I. These results indicate that adenohypophysial activation occurs rapidly and is maximal at the onset of metamorphic climax.