bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of rearing temperature on cuticle permeability and epicuticular lipid composition in Drosophila pseudoobscura
Authors: Toolson Eric C. 
Published: June 2005

AbstractThe effects of larval and pupal thermal regime on adult transcuticular water loss rates and epicuticular hydrocarbon composition in Drosophila pseudoobscura were determined. Temperatures encountered by the larval stage had no effect, but flies emerging from pupae maintained at 24°C exhibited significantly lower cuticular permeabilities than those emerging from pupae maintained at 17°C. More than 50% of the variance in cuticular permeability was accounted for by variation in the proportion of n‐pentacosadiene in the epicuticular hydrocarbons. High transcuticular water loss rates were correlated with higher proportions of relatively short‐chain, methyl‐branched alkanes and alkadienes. High proportions of longer chain lengths of both branched alkanes and alkadienes were associated with lower cuticular permeabilities. The molecular basis for these findings is discussed.
The dynamics of body water in the booklouse Liposcelis bostrychophilus (Badonnel)
Authors: Devine T. L. 
Published: June 2005

AbstractLiposcelis bostrychophilus, whether in culture or fasting, was found to maintain the amount of its body water at nearly 66% of its fresh weight while in air of at least 60% relative humidity between temperatures of 7°C and 42°C. In these conditions intervals of body water loss reaching 1 to 2 μg alternated with recovery of the loss by the physiological absorption of water from vapor at a rate many times that of the water loss. In other conditions a loss of one‐half of the body water could be survived. The time dependence of a change in the mass or the tritium content of body water was that of a single compartment from which water molecules were cleared by first‐order processes, primarily diffusion, having rates in proportion to the momentary mass of body water while water entered from vapor, was metabolically produced, and some evidently was cleared by processes having rates independent of the body water mass. The physiological absorption process was seen to reach its full rate or to stop within minutes, and it was accompanied by a reduced rate of body water clearance. In any particular physical surroundings the body water mass approached a steady‐state value with the half‐time of the first‐order clearance processes. A few measurements of these quantities, over the ranges of temperature and relative humidity, afforded accurate prediction of the recovery time or the longevity in other conditions.
Carbamoyl‐phosphate synthase (ammonia) of rat and axolotl liver: Determination of immunological cross‐reactivity without purification of the axolotl enzyme
Authors: Lamers Wouter H. , De Graaf Andre , Mooren Piet G. , Moorman Antoon F. M. , Charles Rob 
Published: June 2005

AbstractA method has been developed to establish the degree of cross‐reactivity of an antiserum raised against purified carbamoyl‐phosphate synthase (ammonia) from adult rat liver, toward a homologous enzyme from another species without purification of the latter enzyme. For that purpose the ratio between enzyme activity and enzyme protein, i.e., the molecular specific activity in crude liver extracts, was determined by two independent methods.When the molecular specific activity was determined by means of radioimmunoassay using a specific antiserum raised against rat liver carbamoyl‐phosphate synthase this ratio was a factor four higher for the axolotl than for the rat.Both axolotl and rat liver carbamoyl‐phosphate synthase appear as a very prominent band with an apparant molecular weight of 165,000 after sodium dodecyl sulphate‐polyacrylamide gelelectrophoresis. Therefore, the amount of enzyme protein could be determined by means of densitometry of this band using purified rat liver carbamoyl‐phosphate synthase as a standard. The ratio between enzyme activity and enzyme protein calculated from this method appeared to be the same for axolotl and rat.From these results it can be deduced that the degree of cross‐reactivity between rat and axolotl liver carbamoyl‐phosphate synthase is approximately 25% when using the antiserum raised against the rat liver antigen.
Regulation of crustacean morphogenesis in larvae of the mud crab Rhithropanopeus harrisii
Authors: McConaugha John R. 
Published: June 2005

AbstractStarvation of penultimate stage brachyuran larvae within 15 hours after ecdysis results in the suspension of the molt cycle in the early premolt stages. This suspension can be maintained for up to 7 days. Using this as a tool to extend the duration of the penultimate zoeal stage, it was possible to demonstrate that crustacean morphogenesis is at least partially regulated by a time‐dependent process which is independent of the number of larval instars.
Gonadal differentiation in frogs, Rana japonica and R. brevipoda, raised from UV irradiated eggs
Authors: Shirane Terukiyo 
Published: June 2005

AbstractThe gonadal differentiation of anurans, Rana japonica and R. brevipoda, was examined in animals raised from eggs which had been irradiated at the vegetal hemisphere with UV (9300 erg/mm2) at the 2‐cell stage. In R. japonica about 70% of the larvae at stage I from the pressed and UV‐irradiated eggs were germ cell free, but at a stage immediately after metamorphosis all animals had at least some germ cells, although their gonads often were extremely small and poorly differentiated. When male animals matured sexually, many of them had abnormal gonads. However, all of them were shown by artificial means to be capable of fertilization. In the nonpressed and irradiated group, no larvae were germ cell free and the animals immediately after metamorphosis showed nearly normal gonadal differentiation except for the presence of a few degenerate oocytes in the ovaries. The results in R. brevipoda were basically similar to those in R. japonica. In both species, sex ratios were determined at two stages, the first immediately after metamorphosis and the other when the animals matured, as based on gonad morphology and histology and on external sexually dimorphic characters as well. Sex ratios at these two stages in frogs from the pressed and irradiated eggs differed markedly in R. brevipoda. The ratio was normal at metamorphosis but high M/F ratios occurred when animals became mature. That sex reversal took place in this species as well as in R. japonica (in which sex‐ratio deviation was not statistically significant) was supported by the sex ratios of the progenies of these supernumerary males.
Gynogenesis caused by ultraviolet irradiation of salmonid sperm
Authors: Chourrout D. 
Published: June 2005

AbstractGynogenetic rainbow trout lines can be produced easily with the simple UV sperm irradiation technique detailed in this study. The dose effect on embryonic survival rate is called a pseudo “Hertwig effect” because of major differences with results of gamma irradiation: Some mixing of various karyotypes (from diploid to haploid number) were obtained with mean doses, probably because of the weak penetrating power of the ultraviolet rays. Irradiations lasting 4 minutes or more are required to produce homogeneous haploid progeny; heat shock applied to such fertilized eggs results in diploid fry of the maternal phenotype.
Cultivation of mouse embryos explanted at 11 days
Authors: De Villarreal L. Martínez , Fisher D. L. 
Published: June 2005

AbstractA method for cultivation of 11‐day mouse embryos (plug day = day 0) is presented. Competence of the visceral yolk sac and serum dilutions were tested. Eleven day mouse embryos were cultivated for 24 hours with the visceral yolk sac either opened or left intact. Fetal calf serum (FCS) at 0%, 25%, and 50% dilutions balanced with Waymouth's medium was used as cultivation medium. Viability and growth of the embryos were evaluated by heart rate at 6 hours, and protein accumulation and differentiation at 24 hours. At 6 hours, best results were found in those embryos with the visceral yolk sac intact. Serum dilutions at this time were not important for viability. At 24 hours, only those embryos cultivated with the visceral yolk sac opened were alive. Significant increase in viability was obtained when a 50% dilution of FCS was used. There was a significant increase in protein accumulation for viable embryos at 24 hours.
Lactate dehydrogenase of Xenopus laevis laevis and Xenopus borealis depends on a multiple gene system
Authors: Wolff J. , Kobel H. R. 
Published: June 2005

AbstractLactate dehydrogenase isozymes have been reinvestigated in Xenopus laevis laevis and Xenopus borealis. High resolution zymograms of various organs demonstrate that in both species the LDH isozymes are governed basically by a three‐gene system: Ldh‐a coding for positively charged polypeptide, and Ldh‐b and Ldh‐c for negatively charged polypeptides (at pH 8.9). These three LDH subunits when assembled in tetramers show differnetial sensitivity to heat intactivation; the C4 homotetramer in the most liable isozyme. Xenopus is thus similar to Ostechthyes, birds, and mammals that also have a three‐gene system for LDH. With respect to tissue specific isozyme expression, Xenopus resembles the more primitive families of bony fish.Superimposed on this three‐genesystem is a probable gene duplication for both LDH‐a AND LDH‐b. Heterotetrameric isozymes are formed between the various subunits leading to multibanded zymograms with a total of at least 21 distinct zones of LDH activity. The expression of genes is tissue specific not only for the basic genes, but also for their presumed duplicates. Since both species of Xenopus are ancient teetraploids, duplication of Ldh genes is not surprising.
Electron microscopic and biochemical analyses of the organization of human sperm chromatin decondensed with Sarkosyl and dithiothreitol
Authors: Sobhon Prasert , Tanphaichitr Nongnuj , Chutatape Chutima , Vongpayabal Padung , Panuwatsuk Wannana 
Published: June 2005

AbstractHuman sperm chromatin was decondensed by treating the purified sperm heads with Sarkosyl for 60 minutes followed with dithiothreitol (DTT) for 20 minutes and overnight. Following Sarkosyl treatment all histones and nonhistones were removed; the remaining nucleoprotamines in the sperm heads exhibited two levels of higher‐order structure in the forms of 900–1200 Å thick and 380–520 Å thin knobby cords, which were randomly coiled. Subsequent treatment with DTT resulted in the dissociation of the 380–520 Å cords into subunits of 180–210 Å fibers, which were further decondensed into beads‐on‐a‐string structure with diameter of the beads about 120–150 Å.
Effects of advancing age on the ultrastructure of pinealocytes in the male white‐footed mouse (Peromyscus leucopus)
Authors: King Thomas S. , Karasek Michal , Petterborg Larry J. , Hansen John T. , Reiter Russel J. 
Published: June 2005

AbstractQuantitative comparison of pinealocyte ultrastructure in 3‐month‐old and 28‐month‐old male white‐footed mice (Peromyscus leucopus) revealed decreases both in the area of the Golgi apparatus and in the number of dense‐core vesicles. In contrast, no differences between these two age groups were noted in the areas of granular endoplasmic reticulum, vacuoles with flocculent content, lysosome‐like bodies, or motochondra. Nor were any changes between groups of mice apparent in pinealocyte nuclear or cytoplasmic areas, nuclear: cytoplasmic ratios, or the number of pinealocyte nuclei per unit area. areas of unusual, annulate lamellae‐like structures were increased in the pinealocytes of a group of 28‐month‐old mice. These observations suggest a possible age‐associated decrease in the neurosecretory‐like (but not ependymal‐like) secretory process in the pinealocyte of white‐footed mice.
Effects of hormones on postimplantation mouse embryos in vitro. II. Progesterone and estrogen
Authors: Fisher D. L. , De Villarreal L. Martínez 
Published: June 2005

AbstractMouse embryos at day 9 of development were cultured for 24 to 42 h in 50% fetal calf serum and 50% Waymouth's medium containing 0.5 μg/ml insulin supplemented with various amounts of progesterone and estradiol‐17‐β. Unmodified medium contained approximately 0.2% of the normal maternal blood levels for that stage of pregnancy. The addition of 1 × 10−7M progesterone to the medium brought the level near that of the normal maternal circulating amount and appeared to be beneficial for in vitro development. After 24 h of cultivation there was a statistically significant increase in somite number, the number of embryos developing posterior limb buds, and protein accumulation over the control embryos. The addition of small amounts of estradiol‐17‐β (1 × 10−10M) increased the protein accumulation of the embryo over that of progesterone alone and seems to enhance the beneficial effects of progesterone addition.
Development of the spot pattern in the leopard frog
Authors: Bagnara Joseph T. 
Published: June 2005

AbstractExpression of the spot pattern on the dorsal surface of metamorphosing froglets of Rana pipiens seems to be determined by the dorsal integument rather than by the neural crest. At the neurula stage, dorsal ectoderm appears to be loosely determined with respect to pigmentary pattern. Results of skin rotation experiments suggest that by early larval stages the prospective dorsal spot pattern is precisely fixed in the integument.
Studies on the water‐soluble lens proteins of the lizard, Calotes versicolor. II. Electrophoretic and immunological characterization
Authors: Pal J. K. , Nerurkar A. R. , Goel S. C. 
Published: June 2005

AbstractThe Sephadex G‐200 gel filtration fractions C1 to C6 of the water‐soluble lens proteins of Calotes versicolor have been characterized by polyacrylamide gel electrophoresis (PAGE), 7 M urea PAGE, SDS PAGE, and immunological tests. C1 fraction, an α‐crystallin which cross‐reacts with chick α, has very low amount of B chains. It shows two bands in SDS PAGE, one strong and another weak. C2 and C3 fractions, both of which partially cross‐react with chick β ‐crystallins, are largely similar but not identical. C2 in SDS PAGE produces a faint band with a molecular weight of 54,500, which suggests that C2 may either contain a small amount of δ‐crystallin in addition to βH crystallin or that Calotes βH has a high molecular weight subunit like human βH; however, in immunological tests no material cross‐reacting with chick δ was seen. C4 and C5 are low molecular weight, monomeric, and basic proteins which in all probability are not γ‐crystallins.
Role of daylength in the regulation of reproductive function in the male mongoose, Herpestes auropunctatus
Authors: Soares Michael J. , Hoffmann Joan C. 
Published: June 2005

AbstractThe male mongoose, Herpestes auropunctatus, displays a distinct seasonal reproductive rhythm in environments which show minimal changes in daylength. This investigation was designed to evaluate whether the reproductive system of the male mongoose was responsive to photoperiodic manipulations. Four experiments were conducted; two during the breeding season, one during the inactive season, and one during the recrudescence phase. Serum androgen levels and reproductive organ weights were similar in males exposed to either short (6L:18D) or control photoperiods (14L:10D) when the photoperiodic adjustment was initiated in April; however, serum androgen levels were significantly depressed after 60 days exposure to short photoperiods as were weights of prostate glands when the photoperiodic manipulation was initiated in May. An increase in the number of hours of light per day during the inactive season did not affect serum androgen levels or reproductive organ weights. Exposure to a very short photoperiod (2L:22D) during the recrudescence phase delayed, but did not prevent, the increase in serum androgen levels. Although the reproductive system of the male mongoose is responsive to daylength adjustments, the response is less pronounced when compared to the effects of photoperiod in other seasonal breeders.
Spontaneous activation of ovulated rat oocytes during in vitro culture
Authors: Keefer Carol L. , Schuetz Allen W. 
Published: June 2005

AbstractOvulated rat oocytes were observed to activate spontaneously during in vitro culture. The possible mechanisms involved in this activation were studied by culturing oocytes at various times (0–6 hr) after ovulation, in different media, and for different incubation periods (0–5 hr). Activated oocytes extruded the second polar body within 60 to 90 min of culture. Following 3 to 4 hr of culture chromosomes were scattered throughout the cytoplasm; however, no pronuclear formation was observed. Neither time after ovulation nor incubation in different media affected the rate of activation. The length of time the oviducts remained in the animal after cervical dislocation, however, significantly (P < 0.01) affected the rate of activation. Oocytes obtained as rapidly as possible had an activation rate of 21% during in vitro culture, whereas oocytes obtained from oviducts which remained in the animal for 5 min after cervical dislocation had an activation rate of 94%. Therefore, exposure to changing oviductal conditions following cervical dislocation appears to be the critical factor influencing spontaneous activation of metaphase II rat oocytes during in vitro culture. Our studies demonstrate that rat oocytes can spontaneously activate during in vitro culture, a factor which may affect the fertilizability of the oocyte.
Effect of antimetabolites on programming of inner cells of the mouse blastocyst
Authors: McCue Peter A. , Sherman Michael I. 
Published: June 2005

AbstractWhen early blastocysts are subjected to immunosurgery, the resulting inner cell masses (ICMs) regenerate trophoblast cells. In contrast, ICMs from later blastocysts produce endoderm cells. We have found that if embryos are treated with cycloheximide during the transition from the early to late blastocyst stages, subsequently isolated ICMs give rise to trophoblast‐like giant cells. These cells do not, however, exhibit detectable levels of Δ5, 3β‐hydroxysteroid dehydrogenase, an enzyme normally found in primary trophoblast cells. Neither Colcemid nor α‐amanitin affects the conversion of the ICM program in the same way as cycloheximide, although α‐amanitin added at later stages interferes with the formation of a cohesive endoderm layer around the isolated ICM. We propose that the reprogramming of ICM cells involves at least two events: one terminates the giant cell program and the other, occurring later in development, promotes endoderm formation.
Trifluoperazine‐induced meiotic maturation in Xenopus laevis
Authors: Hollinger T. G. , Alvarez I. M. 
Published: June 2005

AbstractXenopus oocytes were exposed to trifluoperazine, a drug that binds to the calcium‐regulating protein, calmodulin. The drug induced meiotic maturation even in the absence of progesterone. When trifluoperazine was microinjected directly into oocytes the maturation of the cells was partially inhibited in that the white spot, indicative of germinal vesicle breakdown, did not appear even though the germinal itself was absent in dissected oocytes.
Shift of seasonal cycle in white‐tailed deer by oral administration of melatonin
Authors: Bubenik G. A. 
Published: June 2005

AbstractA complete reversal of seasonally dependent events, like antler growth and change of pelage was achieved in white‐tailed bucks by oral application of melatonin. The drug was administered in a way that simulated the shortening of the natural photoperiod. Mineralization of antlers, shedding of velvet, complete change of summer pelage, and the onset of the rutting behavior was initiated aproximately 2 months ahead of time.
Visualization of the three‐dimensional distribution of collagen fibrils over preovulatory follicles in the hamster
Authors: Martin Gary G. , Miller‐Walker Cindy 
Published: June 2005

AbstractBefore an oocyte can escape from a preovulatory follicle, the apical wall must thin to the point of rupture. Although numerous layers of cells are present, it is the collagen fibrils in the theca externa that provide most of the strength to the developing follicle. The three‐dimensional distribution and integrity of these fibrils over a follicle cannot be appreciated with standard used methods such as examination of thin sections by transmission electron microscopy. In this paper we describe a technique that removes cells superficial to the collagen fibrils so that their distribution may be examined by scanning electron microscopy. On the third day of the hamster's 4‐day estrous cycle, bundles of fibrils pass from intrafollicular areas and ascend follicles. Approximately halfway up the follicle wall, the bundles fan out and form a meshwork of fibrils which covers the apex. As the time of ovulation approaches, the number of layers of fibrils decreases over the apex until a tear forms in the weakened matrix. Experimental results demonstrating that the meshwork is composed of collagen fibrils are presented. The usefulness of this technique in visualizing the collagen content in preovulatory follicles is discussed as well as factors that may aid in weakening this layer so that follicle rupture may occur.
Effect of selenium deficiency on liver and blood glutathione peroxidase activity in the black bullhead
Authors: Heisinger James F. , Dawson Steven M. 
Published: June 2005

AbstractMale black bullheads, approximately 4 gm, were fed a selenium‐deficient torula yeast‐based diet for 18 weeks, and the activity of glutathione peroxidase was studied in liver and blood using H2O2 as a substrate. Controls were on the same diet, but received weekly intraperitoneal injections of Na2SeO3. At 12 and 18 weeks significant decreases in blood and liver glutathione peroxidase activity were observed in the experimental animals. Liver showed an even greater decrease than blood in glutathione peroxidase activity in the selenium‐deficient animals. Females (4 gm) kept on the diet for 15 weeks showed similar results. Liver activities were not decreased nearly as much when cumene hydroperoxide was used as the substrate instead of H2O2. This indicates that at least two glutathione peroxidase activities are present in fish liver. One is selenium dependent; its activity, as measured with H2O2 as substrate, becomes almost undetectable in selenium‐deficient fish. This situation is very similar to that found in mammalian species.
Protein pattern variability of the hemolymph of mantis shrimp, Squilla mantis L. (crustacea, stomatopoda)
Authors: Ferrero Enrico A. , Graziosi Giorgio , Marzari Roberto , Mosco Alessandro 
Published: June 2005

AbstractThe SDS‐PAGE of Squilla mantis hemolymph reveals 16 major protein bands. Three of them, showing a molecular weight (MW) around 125 kdal, are female specific proteins (FSP) to be considered as vitellogenins because their amount increases with ovarian maturity. The MW of the hemocyanin subunit is confirmed around 70 kdal. Low MW proteins appear or intensify at molt. Hemolymph incubation with 35S‐Methionine and subsequent autoradiography of SDS‐PAGE slabs show that hemocyanin and vitellogenins are not synthesized by the circulating hemocytes, while some proteins connected with molt are heavily labeled by the tracer.