bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of humidity in the seasonal reproduction of male spotted munia, Lonchura punctulata
Authors: Sikdar Malabika , Kar Anand , Prakash Prem 
Published: June 2005

AbstractA systematic long‐term study was made on the possible involvement of humidity in the reproduction of male spotted munia. Both high humidity (90 ± 2%) and continuous illumination (LL) exhibited precocious gonadal development, indicating positive involvement of these 2 factors in the reproduction of this bird. Delay in testicular regression by 2 months in high humidity treated birds suggests a greater role for humidity than photoperiod. © 1992 Wiley‐Liss, Inc.
Electrophoretic studies of meiotic segregation in inter‐ and intraspecific hybrids among East Asian species of the genus Oryzias (Pisces: Oryziatidae)
Authors: Sakaizumi Mitsuru , Shimizu Yasushi , Hamaguchi Satoshi 
Published: June 2005

AbstractThree species of Oryzias, namely, O. curvinotus, O. luzonensis, and four subspecific groups of O. latipes, have been found in East Asia. In order to elucidate the genetic relationships among theses species, fertility and meiotic segregation in hybrids were examined. Fertile males and females and normal segregation were observed in intraspecific crosses of O. latipes and in interspecific hybrids between O. luzonensis and O. curvinotus. By contrast, male sterility and production of non‐reductional 2nd eggs by female were observed in interspecific crosses between O. latipes and O. curvinotus. Similar results were obtained with luzonensis‐latipes hybrids. These results demonstrated that O. luzonensis and O. curvinotus are closely related, and that reproductive isolation is complete between O. latipes and O. luzonensis and between O. latipes and O. curvinotus. © 1992 Wiley‐Liss, Inc.
Gonadal involvement in sexual size dimorphism in the African bullfrog (Pyxicephalus adspersus)
Authors: Hayes Tyrone , Licht Paul 
Published: June 2005

AbstractSexual size dimorphism was investigated in the African bullfrog (Pyxicephalus adspersus), a species in which adult males are about 2.5 times larger than females. Growth profile analysis revealed that males and females begin to diverge in growth rates at 4 weeks postmetamorphosis, concurrent with the appearance of differentiated gonads. At the end of 300 days, males were about 75% heavier and 20% longer than females (females remained previtellogenic). The difference was attributable primarily to an extended period of accelerated linear growth in males between days 166 and 195, and an extended period of accelerated weight gain between days 139 and 166. Surgical gonadectomy did not affect growth in males or females. Reduced plasma steroid levels, failure to show steroid response to GnRH injection, and abolishment of male agonistic behaviors confirmed the completeness of gonadectomy. In addition, there was no correlation between plasma steroid hormones and size or growth rate. The current study suggests that gonadal hormones may not play an “activational” role in establishing sexually dimorphic growth patterns. Sexual size dimorphism may be due to either “organizational” hormonal effects or genetic control of growth patterns. © 1992 Wiley‐Liss, Inc.
Anti‐P450lpr antiserum inhibits specific monooxygenase activities in LPR house fly microsomes
Authors: Wheelock Geoffrey D. , Scott Jeffrey G. 
Published: June 2005

AbstractMonooxygenase activity in microsomes from the LPR strain of house fly (Musca domestica L.) was inhibited by anti‐P450lpr, an antiserum specific for house fly cytochrome P450lpr, Anti‐P450lpr did not inhibit house fly cytochrome P450 reductase or rat cytochrome P450 monooxygenase assays, consistent with specific inhibition of P450lpr. Anti‐P450lpr inhibited the ability of cytochrome P450 reductase to reduce carbon monoxide treated LPR microsomal cytochrome P450, up to 49% of the total, showing that inhibition of cytochrome P450 reduction is the major mechanism of inhibition. Anti‐P450lpr inhibited 98% of methoxyresorufin‐O‐demethylase activity and all the benzo(a)pyrene hydroxylase activity in LPR microsomes, but none of the pentoxyresorufin‐O‐dealkylase activity. The antiserum partially inhibited ethoxyresorufin‐O‐dealkylase and ethoxycoumarin‐O‐dealkylase activity. These results demonstrate that methoxyresorufin‐O‐demethylase activity and benzo(a)pyrene hydroxylase activity are characteristic substrates for P450lpr activity in the LPR strain of house fly. © 1992 Wiley‐Liss, Inc.
The duration of the effectiveness of vitamin A at causing proximodistal duplication in regenerating limbs of the axolotl, Ambystoma mexicanum, in relation to whole body retinoid levels
Authors: Johnson Keith J. , Scadding Steven R. 
Published: June 2005

AbstractUrodele amphibians regenerate their limbs after amputation. Normally, only those parts of the limb distal to the plane of amputation are regenerated. However, retinoids are capable of inducing proximodistal (PD) duplication such that structures already present proximal to the plane of amputation are duplicated in the regenerating limb. PD duplication can be induced by retinoids even if amputation occurs some time after the retinoid treatment. Thus, the purpose of this investigation was to determine for how long after administration, retinoids were effective at inducing PD duplication, and to determine whether this persistent effectiveness was due to some change in the cells of the limb or to residual levels of retinoids in the body. Thus, forelimbs of larval axolotls, Ambystoma mexicanum, were amputated at various times in relation to retinol palmitate (RP) treatment to investigate the relationship between the induction of proximodistal duplications and the timing of the retinoid treatment. RP induced PD duplications when amputation was delayed for up to 2 weeks after cessation of the retinoid treatment. To measure the levels of retinoids actually present within the body, axolotls were treated with RP, and whole body retinoid levels were colorimetrically assayed during and after the RP treatment. Since high levels of retinoids were present for several weeks after the cessation of the treatment, we conclude that the induction of PD duplications, when amputation is delayed until after the RP treatment, is due to the persistence of retinoids in the axolotl body. © 1992 Wiley‐Liss, Inc.
Characterization and partial purification of sperm‐activating substance from eggs of the herring, Clupea palasii
Authors: Morisawa Masaaki , Tanimoto Satomi , Ohtake Hideki 
Published: June 2005

AbstractSpermatozoa of the herring, Clupea palasii, were immotile in a solution of isotonic to seminal plasma but swimming was initiated in a hypertonic solution such as 60% seawater. This suggests that hyperosmolality is a factor for the initiation of sperm motility in herring. The motility of herring spermatozoa in hypertonic solution remained very low but became active in “egg water,” suggesting that a sperm‐activating substance is released from unfertilized eggs and diffuses into the surrounding environment to promote fertilization. The activity of the egg water was heat stable and nondialyzable, and was lost upon digestion with the proteolytic enzyme, pronase E; thus the substance is a protein. During procedures for partial purification using gel‐filtration chromatography on Sephadex G‐75, the substance was found to be very adherent to the Sephadex beads when buffer solution or the lower salt solution was used as the eluate instead of 0.5 M NaCl. This suggests that the sperm‐activating substance might be attached to the surface of eggs in the relatively lower ionic environment of the female reproductive organ and is released from the eggs when they are spawned into the high salt environment of seawater. © 1992 Wiley‐Liss, Inc.
Glutamine metabolism in elasmobranch and agnathan muscle
Authors: Chamberlin M. E. , Ballantyne J. S. 
Published: June 2005

AbstractGlutamine metabolism was investigated in the little skate (Raja erinacea), spiny dogfish (Squalus acanthias), and hagfish (Myxine glutinosa). Amino acid analysis revealed that dogfish plasma glutamine concentration was 11.6 nmol/ml, whereas 48‐fold higher levels, 0.56 μmol/gm, were found in the red muscle. Mitochondria were isolated from the red muscle of the skate and dogfish. The isolation procedure yielded well‐coupled mitochondria, which oxidize glutamine and β‐hydroxybutyrate more rapidly than any other substrate tested. Palmitoyl carnitine was not oxidized, confirming previous studies that elasmobranch red muscle has a negligible capacity for fatty acid oxidation. Glutaminase and glutamine synthetase were measured in the muscle of the hagfish, dogfish, as well as several tissues of the skate. The brain and red muscle have the highest activities of glutaminase, and the activity in dogfish muscle is the highest reported for any muscle. Glutamine synthetase activity is highest in the brain, liver, and kidney, whereas the activity of this enzyme is low or not detectable in elasmobranch and hagfish muscle. The high glutaminase/glutamine synthetase ratio in the muscle indicates that the metabolic organization of elasmobranch and agnathan muscle is geared toward glutamine catabolism. The present study shows that, in addition to β‐hydroxybutyrate, glutamine is an important fuel for elasmobranch red muscle. © 1992 Wiley‐Liss, Inc.
Thyroid involvement in photoperiodically induced testicular and body weight cycles of the black‐headed bunting, Emberiza melanocephala
Authors: Devi Ksh. Pratima , Lal P. 
Published: June 2005

AbstractIn the black‐headed bunting, Emberiza melanocephala, thyroidectomy suppressed the amplitude of light‐induced testicular growth and accelerated the onset of photorefractoriness. Extirpation of the thyroid glands during progressive phase inhibited further testicular growth and led to immediate testicular regression when performed during peak phase of a photostimulated cycle. The inhibitory influence of thyroidectomy on light‐induced testicular growth was fully reversed by daily im injection of L‐T4 at a dose level of 2 μg/bird/day. Neither thyroidectomy nor L‐T4 had any effect on the regressing testes of thyroidectomized buntings. Body weight which was about 26 g increased to about 37 g within 15 days of photostimulation by 20L/4D. Removal of thyroid glands suppressed light‐induced increase in body weight and resulted in premature decline. The inhibitory influence of thyroidectomy on body weight depended upon lipid reserves at the time of operation, an effect which could be reversed by daily im treatments of L‐T4 at dose level 2 μg/bird/day. It is suggested that in the black‐headed buntings thyroid hormones are required for sustaining light‐induced increase in the testes and body weight and may not necessarily be involved in the development of photorefractory states—gonadal and metabolic. © 1992 Wiley‐Liss, Inc.
Monoclonal antibody ST1 identifies an antigen that is abundant in the axolotl and newt limb stump but is absent from the undifferentiated regenerate
Authors: Yang Eric V. , Shima David T. , Tassava Roy A. 
Published: June 2005

AbstractMonoclonal antibodies (mAb) utilized in regeneration studies to date identify antigens that are up‐regulated in the blastema. We obtained a monoclonal antibody, designated ST1 (Stump 1), that is reactive to an extracellular matrix (ECM) antigen exhibiting the opposite distribution; ST1 is an abundant antigen of the limb stump soft tissues but is absent from within the blastema. The border between abundance and absence of mAb ST1 reactivity was sharp and extended as a concavity into the stump. This distinct dichotomy led to further studies relevant to understanding how this extracellular matrix antigen is modulated during regeneration. mAb ST1 reactivity decreased in the internal tissues at the distal end of the limb prior to blastema formation and remained absent until the onset of differentiation. The initial decrease in mAb ST1 reactivity was dependent on the combined effects of injury and the wound epithelium but was nerve independent. At blastema stages of regeneration, the distribution of tenascin, ascertained by mAb MT1 reactivity, closely matched the area without reactivity to mAb ST1. The spatial and temporal distribution of the ST1 antigen in unamputated limbs and during regeneration did not correspond to any previously described ECM component. © 1992 Wiley‐Liss, Inc.
Polarity of responsiveness to sperm and artificial stimuli in medaka eggs
Authors: Iwamatsu T. , Onitake K. , Nakashima S. 
Published: June 2005

AbstractExperiments were performed to ascertain the polarity of responsiveness to sperm and to artificial stimuli in the egg of teleost, the medaka Oryzias latipes. When the eggs were stimulated by sperm or by microinjection of inositol‐trisphosphate or calcium ions, exocytosis of cortical alveoli began earlier at the animal pole than at the equatorial or vegetal pole regions. The propagation velocity of the exocytosis wave through the cortex was constant to the antipode of the egg. When denuded (dechorionated) eggs were inseminated, the number of spermatozoa that penetrated into the cortical cytoplasm was greater in the animal hemisphere than in the vegetal hemisphere. Most of the swollen sperm heads were found around the animal pole area. This distribution pattern of the sperm heads was also observed in both cytochalasin B‐ and colchicine‐treated eggs. These results suggest that there is polarity in the medaka egg regulating the affinity of the plasma membrane for sperm and the responsiveness of the cortex to sperm or artificial stimuli. © 1992 Wiley‐Liss, Inc.
Heat flux, oxygen flux, and mitochondrial redox state as a function of oxygen availability and ciliary activity in excised gills of Mytilus edulis
Authors: Doeller Jeannette E. , Kraus David W. , Shick J. Malcolm , Gnaiger Erich 
Published: June 2005

AbstractThe ciliated gill of bivalve molluscs is situated at an interface between animal and environment. Cilia propel water past the gills to deliver oxygen and nutrition to the animal. Ciliary activity is driven by dynein ATPases and requires a continual supply of ATP at a rate sufficient to match the rate of ATP hydrolysis. Control of the balance between ATP supply and demand in the ciliated gill, and how this balance may be altered by environmental stresses, is unknown. In this pilot study, metabolic flux of excised gills from the marine mussel Mytilus edulis was examined in response to oxygen availability and to serotonin‐stimulated ciliary activity. Heat flux and oxygen flux were measured simultaneously with calorespirometry. In parallel experiments, the redox state of mitochondrial cytochromes was determined with in vivo spectrophotometry. Above 4 kPapO2, heat flux was supported by aerobic metabolism. Anoxic heat flux was less than 5% of aerobic heat flux. Heat and oxygen fluxes nearly doubled in gills in the presence of 10 μM serotonin; however, half‐maximal pO2 for heat and oxygen fluxes and for reduction of mitochondrial cytochromes remained unchanged from control levels. In gills having inactive cilia in half‐strength seawater, half‐maximal pO2 for heat and oxygen fluxes and for cytochrome reduction nearly doubled compared with values in full‐strength seawater. These data indicate that limitation to oxygen delivery imposed by boundary layers may be reduced when ciliary beat frequency is elevated, leading to enhanced oxygen flux to intracellular mitochondria which matches the increased energy demand by the cilia. © 1993 Wiley‐Liss, Inc.
Ontogeny of the capacity for homeoviscous adaptation in white sturgeon (Acipenser transmontanus)
Authors: Buddington Randal K. , Hazel Jeffrey R. , Doroshov Serge I. , Van Eenennaam Joel 
Published: June 2005

AbstractMost fish species tolerate a narrower range of temperatures during their early life history. To ascertain whether this might be related to development of the capacity to regulate membrane fluidity (homeoviscous adaptation), we examined the fatty acid composition of tissue phospholipids from developing white sturgeon eggs, embryos, and prefeeding larvae incubated at temperatures both within the range of natural spawning temperatures (14°), and above (20°) and below (8°). Mortality was highest at low temperature, with the greatest losses prior to neurulation. High temperature also resulted in increased mortality relative to 14°, with peak mortality between neurulation and hatch. At a constant temperature of 14°, significant changes in the fatty acid composition of tissue phospholipids were observed during development, but the patterns of change were altered by development at low and high temperature. Contrary to homeoviscous theory, embryos incubated at low temperature exhibited a decline in the ratio of unsaturated to saturated fatty acids (U/S ratio). In contrast, posthatch larvae exposed to low and high temperature exhibited, respectively, higher and lower U/S ratios than larvae maintained at 14°, implying that the capacity for homeoviscous adaptation is acquired at the time of hatch. Although the lack of a homeoviscous response by embryos may account for low survival at temperature extremes, the specific influences of the observed changes in phospholipid fatty acid composition on the biophysical properties of cell membranes remain to be determined. © 1993 Wiley‐Liss, Inc.
The accumulation of vanadium and manifestation of an antigen recognized by a monoclonal antibody specific to vanadocytes during embryogenesis in the vanadium‐rich ascidian, Ascidia sydneiensis samea
Authors: Uyama Taro , Uchiyama Junko , Nishikata Takahito , Satoh Noriyuki , Michibata Hitoshi 
Published: June 2005

AbstractThe present experiments, using a combination of thermal‐neutron activation analysis for the determination of vanadium and an immunofluorescence method for the recognition of the manifestation of an antigen specific to vanadocytes, clearly revealed the time at which ascidians gain their unusual ability to accumulate vanadium ions during their development. Significant accumulation of these ions was observed after metamorphosis. Two and half months after fertilization, the amount of vanadium in juveniles was about 930 ng per individual, a concentration corresponding to more than 5 orders of magnitude greater than that in unfertilized eggs. A vanadocyte‐specific antigen, recognized by a monoclonal antibody specific to the signet ring cells, first appeared in the body wall after metamorphosis. Three weeks after metamorphosis, the antigen became evident within the cytoplasm of the coelomic cells, which have a single, small vacuole. One and a half months after metamorphosis, signet ring cells appeared for the first time and were specifically recognized by the monoclonal antibody. It is suggested that the accumulation of the vanadium coincides with the differentiation of the vanadocytes during the development of ascidians. © 1993 Wiley‐Liss, Inc.
Mesodermal cell adhesion to fibronectin‐rich fibrillar extracellular matrix is required for normal Rana pipiens gastrulation
Authors: Johnson Kurt E. , Darribère Thierry , Boucaut Jean‐Claude 
Published: June 2005

AbstractNew observations on thin strips of cells from the leading edge of the involuting presumptive mesoderm explanted onto FN‐coated substrata show a striking preferential cellular emigration from the leading edge of explants. Microinjected probes (Fab′ anti‐FN, Fab' anti‐integrin and RGD‐peptides) that disrupt cell adhesion to the FN‐matrix on basal surface of the blastocoel roof also disrupt normal anuran gastrulation, producing blocked embryos with no adhesion of leading edge mesodermal cells to the blastocoel roof, abnormal epiboly, and defects of mesodermal cell spreading across the basal surface of the blastocoel roof toward the animal pole. These results show that the FN‐rich fibrillar extracellular matrix on the basal surface of the blastocoel roof is required for normal gastrulation in Rana pipiens embryos. © 1993 Wiley‐Liss, Inc.
Factors involved in the development of and decline in photoperiodism as it relates to the gonadal activity of a spring‐spawning bitterling, Acheilognathus tabira
Authors: Shimizu Akio , Hanyu Isao 
Published: June 2005

AbstractThe involvement of changes in photoperiodism in gonadal activity was investigated in the spring‐spawning bitterling, Acheilognathus tabira, in which photoperiodism develops during the summer and declines during the winter. In spring, gonadal development occurred without a need for photoperiodic stimulation and independently of the preceding photoperiod (9 hours or 12 hours light; 9L or 12L) during the winter. This observation indicates that the natural photoperiod during the corresponding season is not responsible for the decline in photoperiodism. Fish kept at moderate temperatures (16°C or 22°C) during the winter eventually achieved gonadal maturation, even under short daylength conditions (11L), indicating that low temperature during the winter is not necessary for the decline in photoperiodism. Both treatment with moderate temperature and long days (22°C, 15L) treatment and treatment with moderate temperature and short days (22°C, 11L) induced the development of photoperiodism during the summer, an indication that neither high temperatures during the summer nor long days during the early summer are necessary for the development of photoperiodism in this species. Since the natural photoperiod and temperature conditions during the corresponding seasons are not responsible for the changes in photoperiodism, these changes are probably caused by an internal factor such as circannual rhythm.Alteration of the photoperiodic regime from 11L to even fewer hours of daylight during the period when photoperiodism was declining did not affect subsequent gonadal development. The nature of the changes in photoperiodism in this species is, therefore, a rapid switchover of the responsiveness to daylength rather than a gradual change in the critical daylength for gonadal development. © 1993 Wiley‐Liss, Inc.
Gonadal differentiation and secretions of estradiol and testosterone of the ovaries of Rana catesbeiana tadpoles treated with 4‐hydroxyandrostenedione
Authors: Yu Nai‐Wen , Hsu Chih‐Yun , Ku Hung‐Hai , Chang Li‐Tze , Liu Hwan‐Wun 
Published: June 2005

AbstractLaparotomized female tadpoles of Rana catesbeiana at TK stages X–XII, about 9 months old, were implanted intraperitoneally with empty capsules or capsules containing 4‐hydroxyandrostenedione (4‐OHA), known as an aromatase inhibitor in vertebrates. Histology, gonosomatic index, and secretions of estradiol (E2) and testosterone (T) of the ovaries were investigated. Three months after the treatment, histological examination revealed various degrees of sex reversal in the ovaries treated with 4‐OHA and 79% (57 in 72) were transformed into testes. The ovaries of control tadpoles, however, displayed normal histological appearance. Radioimmunoassay showed that secretion of E2 was decreased while that of T was increased in 4‐OHA treated ovaries. The gonosomatic index displayed a decline tendency from control females through experimental animals to untreated control males. These results indicated that activity of aromatase in the ovaries was inhibited by 4‐OHA, resulting in accumulation of T which induced transformation of the ovaries into testes. © 1993 Wiley‐Liss, Inc.