bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transplantation immunity in the axolotl (Ambystoma mexicanum) studied by blastemal grafts
Authors: de Both N. J. 
Published: June 2005

AbstractTo verify data in the older literature concerning the survival of allografts in the axolotl, a transplantation‐immunological study was carried out in this species. Animals were used from four randomly bred laboratory populations, partly related and partly unrelated. Tolerance for blastemal allografts was shown at 20°C within two of the populations. In one of these the animals were provided with second and third set grafts, which were also tolerated. Allografts exchanged between larvae of related populations always showed prolonged survival. In contrast, grafts exchanged between non‐related populations were frequently rejected. In some cases this rejection was incomplete and was followed by regeneration. Axolotls which tolerated allografts nevertheless rejected blastemal xenografts from other urodelean species. It is concluded that neither immunological unresponsiveness of the host larvae, nor lack of antigenicity of the blastemal grafts is responsible for the prolonged survival of allografts, but that genetic relatedness is the main factor involved.
Physiological studies on supercooled killifish (Fundulus heteroclitus). III. Carbohydrate metabolism and survival at subzero temperatures
Authors: Umminger Bruce L. 
Published: June 2005

AbstractThe previously reported hyperglycemia induced in Fundulus heteroclitus by exposure to the subzero cold was investigated in more detail. It was found that the hyperglycemic response was elicited immediately when fish were transferred to water at − 1.5°C and that the striking increase in serum glucose was accompanied by a progressive depletion of hepatic glycogen. Muscle glycogen occasionally, but not always, showed a slight depletion after long exposure to the subzero cold. Serum glucose was not maintained at high levels indefinitely in the subzero cold. After hepatic glycogen was totally depleted, serum glucose levels began to drop. When serum glucose levels fell to normal, the fish began to die. Addition of glucose to the water elevated serum glucose levels and enhanced survival in the subzero cold. Winter fish, which produce higher levels of serum glucose in the subzero cold than do summer fish, survived the subzero cold almost twice as long as did summer fish. Serum nonglucose free carbohydrate levels were unaffected by the length of exposure to subzero temperatures. Liver protein levels were unaffected by temperatures from 20°C to − 1.5°C and muscle protein levels decreased slightly only after long exposure to the subzero cold.
Innervation and the regulation of acetylcholinesterase activity during the development of normal and dystrophic chick muscle
Authors: Wilson Barry W. , Kaplan Martha A. , Merhoff Wayne C. , Mori Susan S. 
Published: June 2005

AbstractTwo isozymes of acetylcholinesterase (AChE) in the skeletal muscles of the chick embryo decrease to very low levels after hatching. These isozymes have been shown to be maintained in fast twitch muscles, the superficial pectoral and biceps brachii, of birds homozygous for inherited muscular dystrophy. Histochemical studies are presented that associate these isozymes with diffuse AChE activity in the sarcoplasm of embryonic and dystrophic muscle fibers.The hypothesis that neural activity inhibits the activity of the embryonic AChE forms in normal but not in dystrophic muscle after hatching was supported by the fact that biceps muscles of normal chicks denervated at two days still retained embryonic AChE activity when examined one month after denervation. In addition embryonic AChE forms reappeared within three days after denervation in muscles from month old chicks. One month after surgery, total AChE activity of denervated normal muscle was three to four times that of the controls. Moreover, unlike the normal, the AChE activity of dystrophic biceps muscle did not increase following denervation. Tenotomy of muscles from month old chicks had little effect on AChE activity.
Malate dehydrogenases and glutamate dehydrogenase in chick liver and heart during embryonic development
Authors: Greenfield Phyllis C. , Boell E. J. 
Published: June 2005

AbstractThe specific activity of malate dehydrogenase isozymes in cytoplasm and mitochondria of liver and heart have been studied throughout development in the chick. The properties of the isozymes in these tissues are similar to those reported for other tissues. During development, the pattern of the specific activity of the isozymes of liver differs from that of the heart. Activities of the mitochondrial matrix and cytoplasmic isozymes of liver are constant; in heart they increase but not to the same extent. In mitochondria, the activity of malate dehydrogenase varies in the same way as that of cytochrome oxidase. Like cytochrome oxidase, malate dehydrogenase is therefore a constant proportion enzyme. Glutamate dehydrogenase is found in significant amounts in the liver; it is localized in the mitochondrial matrix, and its specific activity remains constant throughout development. In contrast, glutamate dehydrogenase can be detected in the heart only after hatching.
Oogenesis in the suppressor2of Hairy‐wing mutant of Drosophila melanogaster. II. Nucleolar morphology and in vitro studies of RNA protein synthesis
Authors: Klug William S. , King Robert C. , Wattiaux Jean M. 
Published: June 2005

AbstractCytological studies of ovaries from Drosophila melanogaster homozygous for the third chromosomal, female sterile gene, suppressor2 of Hairy‐wing (su2‐Hw), demonstrate that the nurse cell components of the egg chambers are primarily affected. Both chromosomes and nucleoli show qualitative and quantitative differencies from wild type. The in vitro culturing of mutant and wild type ovaries in the presence of labeled RNA and protein precursors were examined using liquid scintillation counting and autoradiography. The results of the scintillation experiments showed the mutant ovary to be nearly equivalent to wild type in the synthesis of RNA, but only half as active in protein synthesis. The autoradiographic analysis revealed that during very short incubation periods, the mutant ovary was more active than wild type in the production of RNA but that the mutant RNA was unstable. The lowered protein synthesis by mutant ovaries was also apparent using autoradiography. Morphometric measurements of mutant and wild type nurse nucleoli indicate a severe reduction in su2‐Hw compared to wild type. These findings suggest that the instability of mutant RNA may be due to some deficiency of the ribosomes produced in the absence of the su2‐Hw+ allele. On the other hand, the autoradiographic studies using H3‐uridine revealed the presence of an extranuclear label in the mutant nucleus not apparent in wild type. The possibility exists, therefore, that the unstable mutant RNA is of extranucleolar origin and thus not ribosomal. In the absence of the su2‐Hw+ allele, translation occurs with poor fidelity leading to the suppression of the phenotypic effects of certain mutant genes. If the ribosomes are responsible for the instability of mutant RNA, normal ribosomes contributed by the heterozygous mother may allow the survival of homozygous mutant flies.
Sulfated extracellular matrix production in the embryonic heart and adjacent tissues
Authors: Manasek Francis J. 
Published: June 2005

AbstractThe incorporation of S35‐sulfate into tissues and extracellular matrix of chick embryos ranging in age from stage 8 (4 somites) to stage 12 (16 somites) was examined. 0.05 mc S35 were added to embryos grown in vitro and after appropriate incubation periods the embryos were fixed and embedded in plastic. Radio‐autographs of 1 μ plastic sections of embryos between stages 8 and 9 (4 to 9 somites) showed heavy S35 incorporation by all tissues, especially the notochord, neural fold and precardia. Between stages 10 (10 somites) and 12 (16 somites) the incorporation of S35 decreases in all tissues examined except the myocardium.These results show that the production of sulfated extracellular matrix is not restricted to chondrogenic tissues in very young embryos, but that this function becomes selectively repressed as the embryo matures. This suggests that S35 incorporation during cartilage production by chondrogenic tissues (such as notochord) in older embryos involves the re‐expression of an earlier embryonic trait, rather than the acquisition of a wholly new capability.The myocardium, on the other hand, continues to secrete a sulfated matrix even after the cells contain well developed myofibrils and become functional myocytes. Embryonic cardiac muscle is therefore a secretory as well as contractile tissue and the two “specialized” functions are not mutually exclusive.
Developmental genetics of the lactate dehydrogenase isozymes of fish
Authors: Whitt Gregory S. 
Published: June 2005

AbstractThree genes (A, B, and E) encoding lactate dehydrogenase (LDH) subunits are shown to be present in fish by: (1) molecular hybridization, (2) allelic variants at two loci, and (3) kinetic, physical, and immunochemical studies. The same studies reveal that the E4 isozyme is closely related to the B4 isozyme. The E4 isozyme is usually synthesized in the regions of the nervous system concerned with vision. However, in some species the E4 isozyme is found in non‐neural tissues such as lens. The closely related B and E loci tend to simulataneously functional in the same retinal cells. The act of hatching by itself does not appear to act as the stimulus to E gene activation. The E subunit facilitates the assembly of A and B subunits into the same teramer. The developmental and tissue specificity of the function of the LDH E gene suggests that the distinctive physical properties and the kinetic behavior of the LDH E4 isozyme may play an important role in the metabolism of teleost vision.
The function of the middle ear in lizards: Crotaphytus collaris (lguanidae)
Authors: Wever Ernest Glen , Werner Yehudah L. 
Published: June 2005

AbstractThe anatomy of the middle ear is outlined for lizards in general and described in detail for Crotaphytus collaris (Iguanidae). By use of the alternating potentials of the cochlea, the general function of the middle ear in the reception of aerial sounds was determined by comparing the ear's sensitivity when the middle ear mechanism was intact with the sensitivity remaining when the columellar shaft was severed, thus eliminating the connection between the stapedial footplate and the more peripheral parts. This comparison was made under two conditions, with the sound applied in the usual way at the external auditory meatus and with the sound introduced through a tube sealed over the oval window. The loss of transmission observed under the first condition is complicated by the presence in the sound path of the nonfunctioning tympanic membrane and by an interaction of sound waves reaching both round and oval windows of the cochlea, but the second condition, in which these complications are avoided, reflects the true performance of the middle ear as a mechanical transformer. This transformer action was measured as 35 db on the average for tones between 300 and 4000 Hz, which is the region of best hearing for this lizard.Further analysis of the operation of the tympanic mechanism was carried out by measurements of sensitivity before and after severing the connection between the internal process and the quadrate bone. These observations showed that the internal process makes little or no contribution to the ear's sensitivity. Other experiments performed with mechanical stimulation showed that the columellar system acts as a reduction lever, and the measurements gave a general indication of the amount of this lever action.The pressure increase provided by the columellar lever, together with a still greater increase produced by the areal ratio between the effective surface of the tympanic membrane and the surface of the columellar footplate, can account in large part at least for the total transformer action. This action makes it possible for acoustic energy to be conveyed with great efficiency from the air to the relatively dense and stiff sensory elements of the cochlea. This problem of the matching of impedances between two media, and its solution by the use of a mechanical transformer, has long been studied in mammals, and especially in the cat, and the solution provided by the lizard's middle ear seems altogether as satisfactory as that provided by the structurally different ossicular mechanism of the mammals.
The structure of pigeon muscle and its changes due to tenotomy
Authors: Hikida Robert S. , Bock Walter J. 
Published: June 2005

AbstractThe tendon of the pigeon's biventer cervicis was sectioned, and the muscle examined histologically after varying post‐operative intervals. Tissues were prepared by routine histological procedures and stained in a number of ways. The results indicate that the fast fibers of the muscle have a faster onset of atrophy than do the slow fibers, but the slow fibers attain the same degree of atrophy in later stages. The onset of atrophic activity is characterized by a swelling of the nuclei and their migration away from the subsarcolemmal position in the twitch fibers. Slow fibers do not show any histological changes at this early stage (6 days). Vacuolization and lipomatosis begin at this stage, as well as some phagocytosis. These characteristics become more prominent as the tenotomy period increases, and connective tissue formation within the fibers can be seen, as well as ring fiber formation and other pathological conditions. The tenotomized muscles demonstrate conditions typical of various human muscle diseases, but differences are noted, and discussed.
Uptake and incorporation of amino acids in minute mutants of Drosophila
Authors: Farnsworth M. W. 
Published: June 2005

AbstractUptake into blood and incorporation into tissue protein of cystine‐35S were assayed in larvae of controls and of five heterozygous Minute mutants of Drosophila melanogaster. The mutants studied were M(2)S‐10, M(2)12, M(2)z, M(3)y and M(3)w. In all mutants, the level of cystine in the blood was significantly higher than in controls and differences in concentration between these mutants were evident. All mutants incorporated cystine into protein, although the specific activities obtained were dependent on genotype. The fraction of the cystine in the blood pool which was incorporated into protein was directly correlated with viability and rate of growth. In contrast, the radioactivity of leucine‐1‐14C, both in blood and in tissue proteins, was not different in M(2)12 and M(3)w heterozygotes as compared to controls, although in M(2)12 the fraction of leucine in the blood pool incorporated into protein was lowered. It was concluded that these mutants possessed a common inability to withdraw cystine (or other sulfur‐containing compounds) from the blood into various metabolic pathways. Feeding activity, digestion and absorption of nutrients appeared normal in these mutants.
Mammalian lung development: Interactions in primordium formation and bronchial morphogenesis
Authors: Spooner Brian S. , Wessells Norman K. 
Published: June 2005

AbstractThe manner in which mouse lung primordia form has been analyzed by observation of trypsin‐isolated gut endoderm from nine‐day embryos. The tissue interactions involved in initial formation of lung primordia and those involved in subsequent morphogenesis of the primordia have been investigated by various organ culture procedures. Mouse lungs form in a manner different from that generally described for amniote embryos. Thus, two lung buds appear first and form the primary bronchi, whereas the trachea appears secondarily.The initial lung buds form at the 25–27 somite stage. Whole‐guts from embryos as young as the two‐somite stage form lung buds in culture. Such buds do not undergo branching morphogenesis if the guts are taken from embryos younger than the 25‐somite stage, but undergo characteristic dichotomous branching if combined with older bronchial mesoderm. If 20–25 somite‐stage endoderm is isolated and cultured in direct combination with gut, older salivary or older bronchial mesoderms, lung buds form. However, such buds only branch in combinations containing bronchial mesoderm. Our results reveal two levels of mesodermal control of lung development. Interactions between nonspecific mesoderm and gut endoderm result in lung bud formation, while those between specific bronchial mesoderm and bud endoderm are required for branching morphogenesis.
Mammalian lung development: Interactions in formation and morphogenesis of tracheal buds
Authors: Wessells Norman K. 
Published: June 2005

AbstractMesoderm present in early developing lung is of two sorts: bronchial, which can evoke formation of bronchial buds from tracheal epithelium; and tracheal, which inhibits bronchial morphogenesis. The latter process correlates with the presence of highly ordered sheaths of collagen and mesoderm cells near the epithelial surface. In contrast, bronchial mesoderm lacks such regularly arrayed components. Initial formation of supernumerary buds on the trachea can be evoked by nonspecific mesoderms, but such buds never branch. Bronchial mesoderm is required if the latter morphogenetic process is to occur.Thymidine labeling experiments fail to provide evidence that differential mitotic activity leads to initial bud formation.
Polar granules of Drosophila. III. The continuity of polar granules during the life cycle of Drosophila
Authors: Mahowald Anthony P. 
Published: June 2005

AbstractPolar granules of Drosophila embryos fragment into fibrous bodies which become associated with the nuclear envelope of pole cells prior to the formation of the embryonic gonad. Similar fibrous structures are found attached to the outer nuclear membrane of primordial germ cells and oogonia throughout the life cycle of the fly. These structures have not been found in any other cell type except the germ cell of the testis. During oogenesis, the oocyte nucleus loses the fibrous bodies associated with the nuclear membrane, but the 15 sister nurse cells retain these structures until the end of vitellogenesis. At this time the cytoplasm and fibrous bodies of the nurse cells are contributed to the ooplasm. Occasionally, polar granules are found in previtellogenic stages of oogenesis, but they only accumulate at the posterior tip of the egg during the latter portion of vitellogenesis. After polar granules have formed, they attach to mitochondria in three species studies, but fail to form this association in D. hydei. Fibrous structures in the egg, believed to be the fibrous bodies attached to the nuclear envelope of nurse cells, are found throughout the mature egg, and have the same species‐specific property of associating or not with mitochondria as was found for polar granules. These fibrous bodies are no longer found following fertilization. A possible role of these fibrous bodies in the egg is discussed.
Culture stability of morphogenetic properties of chick limb‐bud mesoderm
Authors: Finch Robert A. , Zwilling Edgar 
Published: June 2005

AbstractStability of morphogenetic properties of leg bud cells (stage 20+) after two culture procedures was tested with a technique described by Zwilling ('64). This technique involves the placing of the cells to be tested into ectodermal jackets obtained from stage 20–21 limb buds and then grafting the composites either to the dorsum of the wing bud or over the somites of a host embryo. There is a decline in the limb properties between 12 and 18 hours of either shaking flask or plate culture. This decline parallels that observed in the limb bud in vivo. The distal area of the wing dorsum as a graft site partially overcomes the decline of the limb properties. Plating at high cell density retards the decline in morphogenetic properties.It is concluded that the culture conditions used in the present experiments have little, if any, effect on the stability of the morphogenetic properties of leg bud cells. Loss of these properties appears to be time dependent. This situation has possible implications for future in vitro studies of the molecular basis for the properties of the morphogenetic phase of chick limb development.
Effects of diabetes on intestinal growth in the rat
Authors: Schedl Harold P. , Wilson Helen D. 
Published: June 2005

AbstractDiabetes mellitus in rats was induced with alloxan and streptozotocin. Growing rats, six to seven weeks of age, were studied. Growth of the small intestine was compared in diabetic and matched control animals at 5, 8, 44, 55, 70 and 140 days. After five days the total intestinal wet weight was significantly greater in diabetic animals. Intestinal weight of diabetic animals increased progressively in comparison with controls. By 140 days after induction of diabetes, intestinal wet weight was doubled and dry weight was increased by 50% in comparison with controls. Tissue water content was significantly higher in diabetic rats. Body weight of diabetic animals at 140 days was half that of controls. Thus, the ratio of wet weight of intestine to body weight was four times greater in diabetic than control animals. Intestinal length and circumference were significantly increased at 44 days of diabetes. Growth of full thickness gut wall (by the criterion of significantly increased dry weight in g/cm of length) was primarily in the proximal small intestine. The dry weight of mucosal scrapings (g/cm length) was significantly greater in diabetic animals at eight days. The weight of underlying tissue remaining after scraping off mucosa was not significantly different, localizing the growth to the mucosa.
The stress response in the abundance of circulating leucocytes in the killifish, Fundulus heteroclitus I. The cold‐shock sequence and the effects of hypophysectomy
Authors: Pickford Grace E. , Srivastava Anil K. , Slicher Anna M. , Pang Peter K. T. 
Published: June 2005

AbstractWhen intact male Fundulus heteroclitus, adapted to 20°C in sea water, are subjected to three minute immersion at ca. 1°C they pass into a state of transitory coma from which they recover when returned to warm temperature. Hematological studies at recovery time intervals revealed an alternating sequence of leucopenia and leucocytosis that was not accompanied by corresponding changes in the abundance of erythrocytes, in serum chloride or total osmolality. The typical sequence was as follows: leucopenia at three minutes, leucocytosis at 15 minutes, leucopenia at 30 to 60 minutes, and leucocytosis at two hours. This was followed by a gradual return to normal. The major leucocytic cell type resembles a lymphocyte; the cycle was not accompanied by corresponding changes in the abundance of small or large lymphocytes, or in the abundance of eosinophils. Hypophysectomy abolished, or minimized, the second leucocytic phase, but the earlier phases of the cycle were unaffected. Serum glucose increased significantly in the second leucocytic phase.