bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vivo induction of ovarian development in decapitated Aedes atropalpus by physiological levels of 20‐hydroxyecdysone
Authors: Kelly Thomas J. , Fuchs Morton S. 
Published: June 2005

AbstractThe Bass Rock strain of the mosquito Aedes atropalpus is autogenous for the first gonadotropic cycle; i.e. adult females will undergo normal oocyte maturation without the benefit of a blood meal. Yolk deposition can be completely inhibited if these animals are decapitated within 6 hours or abdominally ligated within 8 hours of adult emergence. Injection of 4.8 ng of 20‐hydroxyecdysion into 12‐hour‐old adult females that had been decapitated soon after eclosion restored vitellogenesis in 100% of the treated insects. With this dosage of hormone 50% of the oocytes appeared mature 72 hours after injection. When the amount of hormone administered was increased to 4.8 × 103 ng all of the follicles in 100% of the animals contained yolk, but the average follicle length was 35% less than the vitellogenic follicles of either the non‐decapitated controls or the decapitated females that had received 4.8 ng of hormone.Yolk deposition was not restored in isolated abdomens by 4.8 ng of 20‐hydroxyecdysone. When the dosage was increased to 5 × 103 ng, 100% of the abdomens injected had follicles with yolk, and almost all the follicles contained yolk, but the average follicular length was reduced by 42% compared to intact controls.The vitellogenic activity induced by μg quantities of 20‐hydroxyecdysone in decapitated females or in isolated abdomens is no doubt nonphysiological. However the fact that a single injection of only 4.8 ng of 20‐hydroxyecdysone was capable of inducing in vivo vitellogenesis in decapitated females suggests that this hormone is normally required for this process to occur. Since isolated abdomens did not respond to this amount of 20‐hydroxyecdysone, the possibility that the presence of a thoracic factor, perhaps juvenile hormone, may also be necessary for normal ovarian development in A. atropalpus is discussed.
Ventilation and oxygen consumption in the Dungeness crab, Cancer magister
Authors: McDonald D. G. , Wood C. M. , McMahon B. R. 
Published: June 2005

AbstractThe respiratory system of the crab Cancer magister has been investigated in unrestrained specimens fitted with electrodes for monitoring heart rate, branchial pressure catheters for monitoring scaphognathite rate, a ventilation mask containing an electromagnetic flow probe for measuring instantaneous branchial water flow and water sampling catheters for determining gill oxygen extraction and oxygen consumption. In animals recently stressed by physical restraint and air exposure, heart rate, branchial water flow and oxygen consumption were elevated and both scaphognathites pumped continuously in a predominantly forward direction, whereas in well‐acclimated animals ventilation rate and oxygen consumption were low, gill oxygen extraction was elevated, unilateral ventilation predominated and both ventilatory pauses and periodic reversals of scaphognathite beating were common. Analysis of the relationship between branchial water flow and scaphognathite rate reveals that the scaphognathite operated at a constant stroke volume for forward pumping but not for reverse pumping. Furthermore, the stroke volume was significantly lower for the latter over the normal range of scaphognathite rates in this mode. Reverse pumping and ventilatory pauses are behaviors that often occurred in the apparent absence of extrinsic stimuli in this species, thus their possible roles in gas exchange have been analyzed and are discussed.
Ultrastructure of cell hybrids between mouse oocytes and blastomeres
Authors: Szöllösi D. , Balakier H. , Czolowska R. , Tarkowski A. K. 
Published: June 2005

AbstractCell hybrids were formed between mouse ovarian oocytes and blastomeres from 2‐, 4‐ and 16‐cell stage embryos. No centrioles were located at the spindle pole, no matter what the origin of the blastomere, but microtubule organizing centers (MTOCs) of varying size were regularly present. After fusion the arrangement of the two chromosome sets varied. In some cases the meiotic chromosomes formed metaphase plate I, while the chromosomes of the blastomere under‐went premature condensation and were either scattered on the spindle surface or among the spindle microtubules. In other cases the meiotic and mitotic chromosomes intermingled at random within a large cytoplasmic islet, while a true spindle did not form. None of the hybrids cleaved, although on occasion the first polar body was extruded. The two hemispheres composing the hybrid and originating from the oocyte and blastomere could be recognized due to the presence or absence of cortical granules in the cell cortex.
Supernumerary limb structures with regenerated posterior chick wing bud tissue
Authors: Iten Laurie E. , Murphy Douglas J. 
Published: June 2005

AbstractWhen a large wedge of stage 21 posterior chick wing bud tissue was removed and the cut edges were pinned together, wings with a complete complement of skeletal elements developed in 91% of the cases. Twenty‐four hours after removing this wedge of posterior limb bud tissue, tissue had regenerated that was capable of causing the formation of supernumerary (extra) limb skeletal elements when transplanted to a site in the anterior half of a host wing bud. The extra structures formed were similar to those formed when a wedge of non‐regenerated, posterior edge, stage‐21 wing bud was transplanted to a more anterior position in a host wing bud. When a rectangular shaped portion of posterior edge stage‐21 wing buds was removed and the cut edges were not pinned together, five of 15 cases formed a wing with a complete set of skeletal elements and the rest were missing an ulna and/or digit IV or digits III and IV. Twenty‐four hours after removing this rectangle of posterior‐edge wing bud tissue, tissue had regenerated which, when transplanted to a more anterior position in a host wing bud, resulted in the formation of supernumerary skeletal elements. These results are contrary to those obtained by Fallon and Crosby ('75), who concluded that there was no regeneration of posterior wing bud tissue capable of causing the formation of supernumerary wing structures when transplanted to a more anterior position in a host wing bud.
Concanavalin A binding capacity of preimplation rat embryos
Authors: Wu Jung‐Tsung 
Published: June 2005

AbstractThe number of concanavalin A (Con A) binding sites was determined in Days 2–5 rat embryos (Day 1 = sperm‐positive) by Scatchard plot analysis. There were 127 ± 13 million sites on Day 2 (2‐cell), which were decreased slightly to 88 ± 9 million sites on Day 3 (2 ∼ 4‐cell), then increased to 200 ± 24 million sites on Day 5 morning (early blastocyst) and 175 ± 21 million sites on Day 5 evening (late, implanting blastocyst). However, the apparent association constant decreased steadily with development, from about 3 × 106 M−1 on Days 2 and 3 to 1.3 × 106 M−1 on Day 5 evening.Thus, in comparison with the results of mouse embryos (Wu, '80), the number of Con A binding sites was not increased in the implanting rat blastocyst, as it was in the mouse, although there were comparable numbers of Con A binding sites up to the early blastocyst stage in both species. The data also suggest some changes in the sugar groups, and probably the surrounding groups, on the surface coat of the plasma membrane during the preimplantation stages of development.
Studies on the female sterile mutant rudimentary of Drosophila melanogaster. III. Cell death in rudimentary wing imaginal discs
Authors: Fausto‐Sterling Anne 
Published: June 2005

AbstractPrevious work on the effect of the locus rudimentary on wing morphogenesis showed that a disproportionate reduction in the number of cells in the posterior region of the wing accounted for the changes in wing shape. In the present study, I used both clonal analysis and direct histological observations to demonstrate that the deficiency in cell number in the adult wing resulted from cell death and that cell death can account for the changes in both the size and shape of r wings. Some discussion was devoted to the possible mechanisms by which an alteration in pyrimidine metabolism might lead to cell death.
The physiological control of reproduction in Microdeutopus gryllotalpa (Crustacea: Amphipoda). I. The effects of exogenous ecdysterone on the females' molt and behavioral cycles
Authors: Borowsky Betty 
Published: June 2005

AbstractIn most amphipod crustacean females, the molt is followed shortly by copulation, and this is followed shortly by ovulation. Thus, the ovarian, molt, and behavioral cycles are hypothesized to be coordinated by a master physiological control system. This study presents evidence that the behavioral cycle is tied to the molt cycle. Injections of females with the crustacean molting hormone, 20‐hydroxyecdysone or ecdysterone, hastened the onset of the molt and receptive sexual behavior. This suggests that the behavioral cycle is either tied directly to the level of ecdysterone or tied to some other physiological change associated with the molt that is stimulated by the hormone.
Metabolism of chitin precursors by crayfish tissues during chitin synthesis
Authors: Stevenson J. Ross , Hettick Bruce P. 
Published: June 2005

AbstractIn order to follow changes in chitin precursors during chitin synthesis in the crayfish, Orconectes sanborni, tissue extracts were analyzed with an anion exchange column before and after injection of 14C‐N‐acetylglucosamine. Glucose concentration was found to be much lower in the blood than in the other tissues. Therefore, any movement into the tissues must occur against a steep concentration gradient. In the epidermis, most of the metabolites of the chitin synthetic pathway were absent in early premolt stage D0, and they were at their highest concentration in late premolt stage D3, when chitin synthesis was underway. Apparently the synthesis of these chitin precursors is initiated after premolt state D0. In epidermis, midgut gland, and muscle, the chitin precursors found in highest concentration, N‐acetylglucosamine‐6‐phosphate and UDP‐N‐acetyl‐glucosamine, decreased in concentration between stage D3 and postmolt stage C1‐2, the stage when rate of chitin synthesis is highest. This suggests the early enzymes in the chitin synthetic pathway, but not the late enzymes, increase in activity in premolt, causing accumulation of these two compounds. Then the late enzymes increase in activity in postmolt, reducing the levels of accumulated precursors and raising the overall rate of chitin synthesis. Chitin precursors were found in midgut gland and muscle, but little incorporation of label into macromolecules was seen. This suggests the possibility that these tissues may synthesize chitin precursors for use in chitin synthesis by the epidermis. Some N‐acetyl‐glucosamine‐6‐phosphate was found in the blood, possibly en route from the tissues that synthesize it, such as midgut gland and muscle, to the epidermis, which uses it for chitin synthesis. Even late in premolt, the chitin of the old cuticle, soon to be shed, became labeled. Therefore, the cuticle may serve as a reserve food supply by its continual breakdown and resynthesis.
Variability of response of early Drosophila embryos to heat shock
Authors: Graziosi G. , Micali F. , Marzari R. , de Cristini F. , Savoini A. 
Published: June 2005

AbstractSeveral embryonic stages (nuclear multiplication stage up to blastoderm) were incubated at 37°C. The 84,000 dalton heat‐shock protein was always present in the heat‐shocked embryos at all these stages. This protein was also found in nonheat‐shocked controls. Different amounts of two other heat‐shock proteins, the 70,000 and 68,000 daltons, were synthesized depending upon the embryonic stage. A massive synthesis of these two later proteins was observed in embryos which were able to recover from the heat‐shock.
Polar differences of delayed and implanting mouse blastocysts in binding of Alcian Blue and concanavalin A
Authors: Nilsson B. Ove , Naeslund G. , Curman B. 
Published: June 2005

AbstractMouse blastocysts in delay of implantation and after an 18‐hour activation for implantation by estrogen were recovered by flushing with glutaraldehyde containing Alcian Blue or by flushing with cold Dulbecco's PBS containing 0.1% sodium azide for further processing according to an Alcian Blue technique and a ConA‐latex technique, respectively.Blastocysts in delay of implantation showed no or only faint staining with Alcian Blue, while blastocysts activated for 18 hours displayed a marked staining of the abembryonic pole. Binding of ConA‐latex spheres demonstrated a markedly higher density at the abembryonic end of both delayed and implanting blastocysts. It is concluded that, as demonstrated by the Alcian Blue technique, the abembryonic trophoblast, which is the first one to attach and invade at implantation, has changed the properties of the extracellular coat, probably in a way that favors increase of adhesiveness and invasiveness. The similarity in pattern of ConA binding of both delayed and implanting blastocysts, however, suggests that this property is related more to preimplantational differences in proliferative activity of the two poles than to implantatory changes.
Lactate increases the oxygen affinity of crab hemocyanin
Authors: Truchot J.‐P. 
Published: June 2005

AbstractAt concentrations between 0 and 15 mM, L‐lactate increases the oxygen affinity of the hemocyanin in hemolymph dialysates of the crabs Carcinus means and Cancer pagurus without changing the Bohr effect. A possible role of lactate and other anaerobic end products as cofactors regulating the oxygen transport function is suggested.
Leucine aminopeptidase (aminopeptidase‐I), N‐acetyl‐β‐hexosaminidase and lysosomes in the mussel, Mytilus edulis L., in response to salinity changes
Authors: Moore Michael N. , Koehn Richard K. , Bayne Brian L. 
Published: June 2005

AbstractThe intracellular distribution of aminopeptidase‐I in the intestinal and digestive cells of Mytilus edulishas been shown to be the same as the lysosomal marker enzymes β‐glucuronidase and N‐acetyl‐β‐hexosaminidase. Activity for these enzymes was also associated with the intestinal apical cytoplasm and microvillous border where there was pronounced staining for aminopeptidase‐I. Experimental alterations of salinity induced changes in both microdensitometrically and spectrophotometrically determined aminopeptidase‐I activity, as an increase with raised salinity and a decrease with lowered salinity. Lysosomal hexosaminidase showed similar changes in activity with altered salinity. Cytochemically determined lysosomal stability was also responsive to salinity changes, indicative of alterations in lysosomal functional capability. The lysosomal distribution of aminopeptidase‐I is discussed in terms of the function of lysosomes in intracellular protein turnover, their high concentrations of free amino acids, and the possible roles which these might play in intracellular osmoregulation in response to salinity change.
Influence of thyroxine on suckling rat intestinal alkaline phosphatase and effects of undernutrition on the same
Authors: Subramoniam A. , Ramakrishnan C. V. 
Published: June 2005

AbstractAdministration of daily doses of L‐thyroxine to rats from 18–20 days, but not from 4–7, 11–13, or 25–27 days of age, increased intestinal alkaline phosphatase activity. The typical anterior‐to‐posterior gradient in the enzyme activity was abolished in the hormone‐treated (18–20 days of age) rat small intestine (thyroxine prevented the fall of the enzyme activity orrurring at weaning in the distal part of the small intestine). Thyroidectomy at 14 days of age decreased the enzyme activity (units/gm wet tissue) in the distal part of the small intestine at 21 days of age, but the enzyme activity was unaltered in the duodenum.The enzyme activity in the distal part of the small intestine of pups undernourished by maternal protein deficiency is not influenced by the hormone administration, even from 18–20 days of age, strengthening the hypothesis that failure of maturation of alkaline phosphatase occurs as a result of neonatal undernutrition.
Impaired prepubertal uterine responsivity after neonatal exposure to steroid hormone esters
Authors: Campbell P. S. 
Published: June 2005

AbstractInjection of neonatal rats on day 3 after birth with a single dose of 5 μg or 100 μg estradiol benzoate (EB) or 30 μg or 1,250 μg testosterone propionate (TP) drastically impairs the development of uterine growth responses to exogenous estradiol on day 21 of life. Reduction of uterine responsivity was augmented by EB treatment compared to TP treatment. This may be explained by an apparent reduction in available cytoplasmic estrogen binding sites in the uterus with a concomitant decrease in nuclear retention of the receptor‐estrogen complex which was in addition to the effect upon estrogen‐stimulated metabolic activity (glucose oxidation) resultant from either TP or EB exposure. The degree of reduced uterine responsivity at 21 days of age directly corresponds to the degree of reduction in the ovarian weights observed in the neonatally treated rats. Neonatal ovariectomy on day 3 of life also produced a uterine response syndrome characteristic of neonatal estrogenization. Thus, it is suggested that endogenous estrogen secretion during infancy may be important in end organ conditioning in the development of a functionally competent uterus.
Synchrony of oogenesis in laboratory‐maintained and wild populations of the purple sea urchin (Stronglyocentrotus purpuratus)
Authors: Leahy Patrick S. , Hough‐Evans Barbara R. , Britten Roy J. , Davidson Eric H. 
Published: June 2005

AbstractCycles of oogenesis were studied in populations of Strongylocentrotus purpuratus by disaggregation of ovaries and measurement of the number of vitellogenic and mature oocytes. Average egg yields upon spawning were recorded. As reported by many previous authors, fecundity of intertidal S. purpuratus females is seasonal. Two peaks of fertility are observed per year in subtidal animals from a southern California location, and for some months of each year virtually none of these animals contain vitellogenic or mature oocytes. In contrast, a fraction of animals living at 50–70‐foot depths in a kelp bed display vitellogenic and mature oocytes at all seasons of the year. Different individuals in these deep‐water sea urchin populations are in different stages of the process of oogenesis at any one time, and their fecundity is not entrained with the seasons. Annual yield of eggs of average females in deep‐water and intertidal populations is about the same. Groups of mature females derived from both deep‐water and subtidal populations and held in our large scale laboratory S. purpuratus maintenance system (SpMS) resemble the deep‐water populations. Reproductive cycles in these females are in different phases even within the same tank and remain so for at least several years. Initially synchronous populations eventually drift apart in phase when held in the SpMS in the absence of seasonal environmental stimuli. We show that in SpMS females the fertility of each group can be predicted from oocyte count data, and that it can to a large extent be controlled by the frequency of induced spawning.
Absorption of protein molecules by the small intestine of the bullfrog tadpole, Rana catesbeiana
Authors: Sugimoto Keiji , Ichikawa Yasuaki , Nakamura Itsuo 
Published: June 2005

AbstractIn the tadpole of the bullfrog, Rana catesbeiana, the absorptive cells of the small intestine are characterized by the presence of invaginations of the surface plasma membrane or pinocytic vesicles in the apical cytoplasm and numerous lysosomes in the supranuclear region. These cytological features suggest that the absorptive cells may be able to ingest some macromolecules or particles. The possibility of macromolecular absorption in this animal was examined by using horseradish peroxidase (HRP) and the electron microscopic cytochemical technique. Exogenous HRP was ingested in the absorptive cells by pinocytosis and then accumulated in multivesicular bodies (MVBs) by the contribution of pinocytic vesicles to MVBs. The pinocytic vesicle changed its shape to have an inner vesicle. Some of the inner vesicles of MVBs seem to have originated from the inner vesicles of pinocytic vesicles. Almost all the MVBs in the subapical region showed HRP activity, but some of them showed no acid phosphatase (AcPase) activity; those in the supranuclear region always showed an intense AcPase activity. Therefore some of the subapical MVBs are heterophagosomes and may be joined with lysosomes during the movement toward the supranuclear region. The MVBs with lysosomal enzymes in the subapical or supranuclear region are presumably important sites of intracellular digestion. The results indicate that intracellular digestion may occur in the small intestine of the bullfrog tadpole under natural conditions.
A triple‐stain technique for evaluating normal acrosome reactions of human sperm
Authors: Talbot Prudence , Chacon Richard S. 
Published: June 2005

AbstractA triple‐stain technique has been developed to score normal acrosome‐reacted human sperm in fixed smears. Live and dead sperm are first differentiated using the vital stain trypan blue. Sperm are then fixed in glutar‐aldehyde, dried onto slides, and the postacrosomal region and acrosome are differentiated using Bismark brown and Rose Bengal. Slides are examined at 1,000 × with a bright‐field microscope and assessed for (1) the percentage of sperm that were alive at the time of fixation and (2) the percentage of sperm that had undergone normal acrosome reactions. Experiments are included that show that trypan blue is a reliable stain for dead sperm and that Rose Bengal stains only sperm having intact acrosomes. This technique may have applications in experimental and clinical studies on sperm capacitation, acrosome reactions, and fertilization in laboratory and domestic animals as well as in man.
Red light insensitivity of the extraocular pathway for photoperiodic stimulation of reproductive development in the slug, Limax maximus
Authors: Sokolove Phillip G. , Kirgan James , Tarr Robert 
Published: June 2005

AbstractSlugs (Limax maximus) that have been blinded by removal of their optic tentacles mature in long days with white light photoperiods (LD 16:8) but fail to undergo male‐phase reproductive maturation in response to long‐day, red‐light photoperiods (> 600 nm; RD 16:8). Intact slugs, in contrast, mature in either RD 16:8 or LD 16:8 light cycles. On short days (LD 8:16) both intact and blinded slugs remain immature and gain less weight than on long days.
Effects of amiloride and SITS on branchial ion fluxes in rainbow trout, Salmo gairdneri
Authors: Perry S. F. , Randall D. J. 
Published: June 2005

AbstractThe effects of amiloride and SITS on branchial ion fluxes in rainbow trout were examined. Each drug was found significantly to inhibit both influx of Na+ and Cl− ions. It is postulated that the inhibitory effects on the contralateral exchange processes result from changes in gill epithelial cell pH.