bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dietary regulation of digestive enzyme levels in the water snake, Natrix tessellata
Authors: Zhalka Mhmoud , Bdolah Avner 
Published: June 2005

AbstractLevels of digestive enzymes were analyzed in water snakes following artificial feeding. A prominent increase of total proteolytic activity in the stomach was evident after feeding with a casein solution or after the snake was offered a fish (9‐ and 6‐fold that of the fasting level, respectively). The activity following feeding with starch was much lower. Increased levels of chymotrypsin(ogen) as well as of amylase were evident in the pancreas 1 day after feeding the snake with fish. A specific induction of increased level of chymotrypsin in the pancreas of adult snakes was achieved by feeding with casein (12‐fold that of the fasting level). In the group fed with starch, the chymotrypsin level dropped, while a 3‐fold increase of amylase was evident. In newborn snakes, fed for the first time, casein induced a dramatic increase in the level of chymotrypsin in the pancreas (58 times the fasting level); feeding with starch induced an approximate 2‐fold increase of chymotrypsin. Histological examination of the pancreas 1 day following casein feeding showed acinar cells loaded with zymogen granules. In starved animals and in snakes fed with starch, a much lower concentration of zymogen granules was observed. The pancreas of the snake may, thus, be most suitable for studying the specific induction of synthesis of digestive enzymes.
Ketoglutarate dehydrogenase from ribbed mussel gill mitochondria: Modulation by adenine nucleotides and calcium ions
Authors: Karam George A. , Paynter Kennedy T. , Bishop Stephen H. 
Published: June 2005

AbstractThe transient accumulation of proline in the gills of the osmotically stressed ribbed mussel (Modiolus demissus), may be controlled by a transient regulation of the α‐ketoglutarate dehydrogenase (KGDH) activity. In this study, KGDH was partially purified from lysed mitochondria of gill tissue by differential centrifugation techniques. Various modulators of enzyme activity assayed at a saturating concentration (2.5 mM) of ketoglutarate (KG), showed inhibition by high concentrations of Cl− (10–100 mM) and a slight activation or inhibition by the other compounds (10 mM), when assayed in the absence of added Ca++. Addition of Ca++ at pH 7.2 caused no change in Ks0.5 for KG and a 1.5‐fold increase in Vmax whereas at pH 7.8, no change in Vmax but a 40–50% decrease in Ks0.5 and slight positive cooperative effects (“napp” 1.4–1.7) were observed. At pH 7.8, addition of adenine nucleotides (AMP, ADP, ATP at 5mM) had no effect on the Vmax; however, ATP and ADP lowered the Ks0.5 by 3.5–4‐fold. The CoA derivatives of short chain fatty acids were found to inhibit the enzyme by 30–60%. This inhibition was reversed by Ca++ but only at higher KG concentrations (250 μM). The enzyme showed a major change in activity at nicotinamide adenine dinucleotide/reduced nicotinamide adenine dinucleotide ratio (NAD/NADH) > 1, an effect that could not be modified by Ca++. It appears, therefore, that the mussel gill KGDH is mainly regulated by changes in mitochondrial pH and ketoglutarate or adenine nucleotide levels, rather than by changes in mitochondrial calcium levels.
Isolation and characterization of a taurine‐specific opine dehydrogenase from the pedicles of the brachiopod, Glottidea pyramidata
Authors: Doumen C. , Ellington W. R. 
Published: June 2005

AbstractTauropine dehydrogenase (pyruvate + taurine + NADH ⇋ tauropine + NAD+) was partially purified from the pedicles of the inarticulate brachiopod, Glottidea pyramidata. The molecular mass of this enzyme, as determined by high performance liquid chromatography (HPLC) using a TSK‐ 3000 SW column, was 39,500 daltons. This molecular mass value is consistent with a monomeric structure characteristic of all opine dehydrogenases. Kinetic studies revealed that taurine and pyruvate were the preferred substrates, although other amino acids and keto acids were used to some extent. This enzyme readily oxidized tauropine displaying an apparent Km of 3.1 mM. Taurine was found to be the most abundant free amino acid in neutralized perchloric acid extracts of pedicles. Thus, it is likely that taurine is a physiological substrate. This enzyme shows striking similarities to tauropine dehydrogenases from archeogastropods.
Differentiation of the anterior latissimus dorsi muscle of the chicken examined by anti‐myosin monoclonal antibodies
Authors: Zhang Yatian , Shafiq Saiyid A. 
Published: June 2005

AbstractTwo new monoclonal antibodies (McAbs), ALD‐180 and ALD‐88, produced against the myosin of the slow anterior latissimus dorsi (ALD) muscle of the chicken are described. Their specificity for myosin heavy chain (MHC) was established by radioimmunoassay, immunoautoradiography, and immunofluorescence. They were used in conjunction with McAbs MF‐14 and MF‐30 (which have been characterized previously to be directed against MHC of the fast skeletal muscle) to examine the developmental changes of the chicken ALD muscle. At the 16‐day embryonic, early posthatch, and adult stages the ALD muscle fibers differed in their reaction pattern with the McAbs: at the embryonic stage all fibers reacted strongly with ALD‐180 and weakly with ALD‐88 and MF‐30; at the early posthatch stage there was a checkerboard pattern with many fibers not reacting with any of these three McAbs; and at the adult stage all fibers reacted strongly with ALD‐180 and ALD‐88 and weakly with MF‐30. The MF‐14 antibody did not react with ALD muscle at any developmental stage. The mature pattern of immunoreactivity of the ALD muscle fibers with the antibodies was established only after 9 weeks posthatch, and during this 9‐week period the immunofluorescence changes were nonsynchronous. Based on immunocytochemical evidence of changes in myosin isoform expression, this study clearly demonstrates a distinctive neonatal (early posthatch) stage in the development of the chicken slow muscle.
Uterine luminal proteins during the preimplantation period in the ferret
Authors: Foresman Kerry R. 
Published: June 2005

AbstractThe pattern of synthesis of uterine luminal proteins during the 6‐day preimplantation period of the ferret has been analyzed by polyacrylamide gel electrophoresis and fluorography. The results demonstrate that several classes of protein, in particular those of molecular weights of 75,000, 58,000, 50,000, 18,000, and 8,000, are actively synthesized and appear in the uterine lumen during this period. Quantitative changes in the amount of radioactivity incorporated by specific proteins as viewed on autoradiograms are also suggested in association with the observed qualitative changes and both become more prevalent as implantation approaches.
Role of fat bodies in oocyte growth and recruitment in the frog Rana cyanophlyctis (Schn.)
Authors: Prasadmurthy Y. S. , Saidapur S. K. 
Published: June 2005

AbstractEffects of 30‐day bilateral fat body excision in February and November and replacement with 10 or 20 mg fresh aqueous fat body homogenate 6 days a week for 30 days, unilaterally or bilaterally fat body excision plus 20 IU human chorionic gonadotrophin (HCG) in February, and long‐term (60 days) fat body excision in March—April were studied in Rana cyanophlyctis. In addition, the effect of ovariectomy on fat body weights in February and November was also studied. The frogs were fed 6 days a week with live guppies and libitum. The ovarian follicular kinetics was studied by estimating the numbers of first growth phase (FGP), medium and large second growth phase (MSGP and LSGP) oocytes and atretic follicles. Regardless of season, 1‐month fat body ablation caused a significant reduction in LSGP oocytes, gonadosomatic index, and increase in atretic follicles. Administration of 20 mg fat body homogenate to fat‐body‐excised frogs prevented the fall in the number of LSGP oocytes and the gonadosomatic index. In fact, there was a significant increase in the LSGP oocytes and percentage weight of ovaries in these frogs. Follicular atresia was greatly reduced due to fat body homogenate (10 or 20 mg) administration. In 30‐day unilaterally fat‐body‐extirpated frogs, the mean weight of the ipsilateral ovary was reduced to 50% compared to that of the shamoperated frogs due to increased follicular atresia and associated decrease in LSGP oocytes. The administration of HCG increased recruitment of SGP oocytes in unilaterally as well as bilaterally fat‐body‐ablated frogs. This was accompanied by a reduction in atresia of oocytes and elevation of the gonadosomatic index. Interestingly, in long‐term fat‐body‐ablated frogs, ovarian weight recovered and follicular kinetics in them was identical to that found in shamoperated control frogs. Furthermore in 30‐day ovariectomized frogs, in both seasons there was a significant rise in fat body weights. The above findings in R. cyanophlyctis suggest that fat bodies have a role in vitellogenesis, and they serve as immediate sources of lipid energy needed for follicular growth. If adequate food is provided to fat‐body‐excised frogs, after an initial setback, ovarian growth commences by drawing lipids from other sources. It is concluded that fat bodies in the frog have a supporting and possibly not an obligatory role in vitellogenic growth of oocytes.
Fucosylated glycoconjugates appear on mouse embryos during blastocyst formation
Authors: Dealtry Gillian B. , Curry Mark R. , Sellens Martin H. 
Published: June 2005

AbstractMouse embryos were analysed for expression of surface glycoconjugates using a panel of fluorescein‐labelled lectins. Morulae and blastocysts but not early cleavage stages stained brightly with fucose binding lectins. By contrast, cleavage stages stained brightly with all the other lectins tested. These findings provide evidence for substantial reorganisation of the cell surface during blastocyst formation and are consistent with a role for fucosylated glycoconjugates in compaction.
Abnormal Development in Artemia: Defective emergence of the prenauplius with bicarbonate deficiency
Authors: Trotman Clive N. A. , Gieseg Steven P. , Pirie Richard S. , Tate Warren P. 
Published: June 2005

AbstractPrenauplius larvae of the brine shrimp Artemia emerged abnormally from their survival cysts in certain substitutes for seawater unless the concentration of metabolising cysts exceeded about 1 mg/ml. Emergence was normal in natural seawater. The abnormality was manifest as the release of prenauplii trapped within an additional membrane surrounding the hatching membrane, preventing normal development. It was shown to be caused by a failure of the cyst inner cuticular membrane to rupture when the remainder of the cuticle and the external tertiary envelope ruptured. The biochemical basis of the abnormal emergence was found to be a deficiency of bicarbonate ion, and a requirement for this ion for normal emergence was demonstrated. In the model of the normal emergence mechanism, bicarbonate is now implicated as an additional component in the energy‐requiring process for the generation of the osmotic potential necessary for successful expulsion of the prenauplius.
Actin‐plasma membrane associations in mouse eggs and oocytes
Authors: Longo Frank J. 
Published: June 2005

AbstractUsing rhodamine‐phalloidin stained preparations and extracted specimens labeled with heavy meromyosin or run on polyacrylamide gels, actin–plasma membrane associations in mouse mature eggs at the second metaphase of meiosis and oocytes at meiotic prophase have been examined. Cortices of extracted oocytes possessed numerous actin filaments that emanated from the plasma membrane delimiting regions between microvilli and from microvillar apices. The membrane anchorage sites of actin filaments were marked by an electron dense material on the inner leaflet of the plasma membrane. The free ends of filaments emanating from the plasma membrane of oocytes intermeshed to form a dense, cortical layer. With meiotic maturation, changes in the organization of cortical actin were first noted approximately 3 hr after the chromosomes had become localized at the oocyte's periphery. Fewer and shorter actin filaments, which did not form a well‐defined layer as in oocytes, were connected with electron‐dense material to the inner leaflet of the plasma membrane of extracted egg cortices in regions other than that associated with the meiotic spindle. Cortical actin adjacent to the meiotic spindle, however, was organized into a dense, cresentic aggregation in which clusters of filaments emanated from electron‐dense regions associated with both the inner and outer leaflets of the plasma membrane. These observations indicate that mouse oocyte maturation not only involves changes in the distribution of cortical actin but also local alterations in the association of actin with the plasma membrane.
The absence of DNA from the blood serum of Bufo arenarum
Authors: De Recondo Marta Elena Fernández , De Arcuri Beatriz Eugenia Fernández , Recondo Eduardo Francisco 
Published: June 2005

AbstractThe absence of DNA from the blood serum of the toad Bufo arenarum was confirmed by classical colorimetric techniques and by a new method which allows differentiation between DNA and the glycosaminoglycans (GAG). A component of serum which had some of the properties of DNA was identified as a GAG. This component gave positive reactions in colorimetric assays for DNA, but the absorption spectra were completely different from those of authentic DNA. The compound was also not hydrolized at all by treatment with deoxyribonuclease.
Role of carbohydrates in cell‐substrate interactions during newt epidermal cell migration
Authors: Atnip Karen Davenport , Mahan James T. , Donaldson Donald J. 
Published: June 2005

AbstractThe effect of several solubilized monosaccharides on epidermal cell migration from skin explants of the adult newt was examined. The ability of epidermal cells to migrate on substrates coated with these same sugars or with wheat germ agglutinin (WGA) was also determined. Adding 0.05 M Nacetyl‐glucosamine (GlcNAc) to the medium inhibited epidermal cell migration in dishes coated with either type I collagen or fibrinogen. The same concentration of fucose, galactose, or mannose had no effect. In contrast to type I collagen, which supported considerable migration when dried onto the bottom of plastic dishes, epidermal cells were unable to migrate on dishes coated similarly with WGA, mucin (a protein high in sialic acid residues), or bovine serum albumin (BSA) conjugated to galactose, mannose, or GlcNAc. Red blood cell (RBC) binding assays showed that drying WGA onto plastic did not destroy its GlcNAc binding sites—nor did it damage the GlcNAc residues of BSA‐GlcNAc. The RBC assay also verified that for both these proteins, substrates with distinctly different cell binding capacities had been tested in the migration experiments. In dishes coated with either WGA or BSA‐GlcNAc, red cells bound to dish bottoms in a GlcNAc‐specific manner right up to the margins of explants. Other control experiments showed that the failure of migration in WGA‐ and BSA‐GlcNAc‐coated dishes could not be explained by competition between adsorbed and desorbing protein for cell surface receptors. This work shows that adhesive bonds between epidermal cell surface GlcNAc and a GlcNAC‐specific lectin on the substrate are not by themselves adequate to support cell migration. Nor is GlcNAc, sialic acid, galactose, or mannose alone on the substrate sufficient. In conjunction with our earlier work (Donaldson and Mahan: J. Exp. Zool., 231:211–219, '84; Donaldson, Mahan, Hasty, McCarthy, and Furcht: J. Cell. Biol., 101: 73–78, '85), these observations suggest that factors other than carbohydrate content or capacity to act as a lectin determine whether a given extracellular protein will support migration.
Ontogeny‐related changes in the peptide profiles of the germinal epithelium: Analysis by sodium dodecyl sulfate gradient gel electrophoresis
Authors: Kumari Meena , Duraiswami S. 
Published: June 2005

AbstractThe premise that one manifestation of the nexus between Sertoli cells and germ cells may be an orderly and sequential change in their protein profiles has been examined in relation to the ontogeny of spermatogenesis in the colony‐bred albino rat. Viable “Sertoli cell—germ cell associations”The term “Sertoli cell—germ cell associations” is used to designate the groups of Sertoli cells together with the associated germ cells (in other words, a part of seminiferous epithelium) that are recovered after enzymatic removal of tunica propri from the seminiferous tubule fragments (Welsh and Wiebe, '75; Meenakumari and Duraiswami, '86b).
isolated from the testes of animals of defined postnatal age and incubated in an appropriate medium were separated into a Sertoli cell and a germ cell fraction and processed for analysis by sodium dodecyl sulfate gradient gel electrophoresis. The resulting stained bands were “mapped” and assigned relative mobility values by comparison with standard marker proteins. This enabled identification by serial number of individual bands from an overall total of 163. For purposes of detailed analysis, they were classified into high, medium‐high, medium, and low molecular weight bands. Two major categories were delineated: 1) those associated uniquely with a specified day of ontogeny and 2) those appearing intermittently. Significantly enough, not one of the bands was encountered on all days examined. The relevance of the patterns observed to the possible exchange of “information” between Sertoli cells and germ cells during spermatogenesis is mooted.
Inhibition of mouse oocyte cyclic AMP phosphodiesterase by steroid hormones: A possible mechanism for steroid hormone inhibition of oocyte maturation
Authors: Kaji Eugene , Bornslaeger Elayne A. , Schultz Richard M. 
Published: June 2005

AbstractTestosterone, progesterone, and estradiol‐17β each inhibit cAMP phosphodiesterase activity of mouse oocyte extracts in a concentrationdependent manner. This finding provides an explanation for the inhibitory effect of steroid hormones on germinal vesicle breakdown (GVBD) of mouse oocytes in vitro. Furthermore, it raises the possibility that steroid hormones present in follicular fluid participate in maintaining meiotic arrest in vivo by acting in a nonclassical manner.
New evidence of anuran oviducal pars recta involvement on gamete interaction
Authors: Miceli D. C. , Fernández S. N. , Mansilla Z. C. , Cabada M. O. 
Published: June 2005

AbstractCoelomic oocytes of the toad Bufo arenarum are not fertilizable when inseminated in egg water that assures fertilization of dejellied uterine eggs. However, when coelomic oocytes were pretreated with an extract from oviducal pars recta (PRE) and inseminated in egg water, a high frequency of fertilization was obtained.In this study the effect of PRE on acrosome breakdown (AB) was studied by means of vitelline envelope (VE) lysis and fertility tests with B. arenarum sperm, and by direct observations with the light microscope of the AB with Leptodactylus chaquensis sperm. The coelomic envelope becomes sensitive to lysin solution only after PRE treatment. The addition of sperm to PR‐treated oocytes, in a medium containing egg water, resulted in a marked swelling and softening of the VE. But this lytic effect by sperm can be observed only when egg water was present in the medium. These results indicate that jelly‐molecules are necessary for the acrosome process to begin and that PR components engulfed in the VE are not capable of inducing AB by themselves. Likewise, incubation of B. arenarum sperm with PRE did not impair their fertilizing capacity and the supernatant of this incubation medium did not have typical VE lytic activity.Moreover, when the effect of PRE on AB was studied by direct observation of L. chaquensis sperm, it was found that PRE neither induces AB nor modifies its time‐course.
Removal of enveloping follicle cells can trigger resumption of meiotic maturation in Fundulus heteroclitus oocytes
Authors: Greeley Mark S. , Begovac Paul C. , Wallace Robin A. 
Published: June 2005

AbstractThe various somatic cell layers surrounding large (1.3–1.4 mm in diameter) meiosis‐arrested oocytes of the saltmarsh teleost Fundulus heteroclitus were successively removed by a combination of manual dissection and exposure to calcium/magnesium‐free medium. The efficacy of these methods was verified by light and scanning electron microscopy. Oocytes within intact follicles, and oocytes in follicles with the outermost surface epithelium and theca layers removed, typically resumed meiosis only when treated with either a steroid, 17α‐hydroxy‐20β‐dihydroprogesterone, or an aqueous extract of Fundulus pituitaries. In contrast, removal of the follicle cell layer immediately surrounding the oocyte frequently triggered the resumption of meiosis in the absence of exogenous hormonal stimulation. These results suggest that the follicle cells may somehow be responsible for the maintenance of meiotic arrest in non‐hormone‐treated oocytes.
Fucosylated glycoconjugates in mouse preimplantation embryos
Authors: Kimber S. J. , MacQueen H. A. , Bagley P. R. 
Published: June 2005

AbstractPreimplantation mouse embryos were metabolically labelled with 3H or 14C‐fucose to investigate the synthesis of fucosylated macromolecules. Scintillation counting revealed that there was a progressive increase in both total fucose taken up by the embryo and incorporation of fucose into TCA‐precipitable material as embryos developed from the 4‐cell to the blastocyst stage. This was reflected in the increasing intensity of bands on autoradiographs of radioactive fucose labelled proteins separated on 10% SDS‐PAGs between the 4‐cell embryo (at which stage bands were first detectable) and the blastocyst. Minor qualitative changes in fucoproteins were detected at the time of compaction and additional bands appeared at the blastocyst stage. Preliminary analysis of fucolipids in 6‐ to 8‐cell embryos indicated that an approximately equal amount of fucose was incorporated into lipid and protein. Autoradiographs of semi‐thin sections of 3H‐fucose‐labelled embryos showed substantial amounts of radioactive material in the vicinity of the plasma membrane both adjacent to other cells and facing the zona pellucida. These data would support a predominant role for fucoconjugates in cell surface events in the preimplantation embryo from the 8‐cell stage.
Social control of testicular steroidogenic capacities in the Siamese fighting fish Betta splendens Regan
Authors: Leitz Thomas 
Published: June 2005

AbstractMale Siamese fighting fish (Betta splendens Regan) of the veiltail variety were raised. At the age of 4 ½ months they were either isolated or community‐housed for 2 ½ months. After that time the relative fin lengths were determined, and the in vitro metabolism of testosterone by the testes of the fishes was investigated. Community‐housed specimens had shorter fins than the isolated males. Their testes formed less 11‐oxy‐ and more 5β‐steroids than those of the isolated males. This difference was even larger when high‐ and low‐ranking community‐based specimens were compared. The appearance of low‐ranking males resembled that of females, and the main products of their testes were 5β‐reduced steroids. These results are interpreted as evidence for a social control of steroid metabolism and hence reproductive ability in the fighting fish.