bluuebunny/crossref_metadata_2025 huggingface dataset:
Prostaglandin E2 and reproduction in the male crested newt, Triturus carnifex (Laur.)
Authors: Gobbetti Anna , Zerani Massimo
Published: June 2005

Plasma prostaglandin E2 (PGE2) and sex hormones (progesterone, androgens, and 17β‐estradiol) were determined in the male crested newt, Triturus carnifex, during the annual sexual cycle. In vivo experiments were carried out to study the effects of PGE2 on plasma sex hormones during prereproduction, reproduction, and postreproduction; contemporaneously, in vitro experiments were performed to study the effects of PGE2 on the testicular release of sex hormones. The effects of one week's captivity on PGE2 and sex hormones was also evaluated. Plasma PGE2 increases in autumn, during the recovery of gonad and secondary sexual characteristics; it peaks in January, at the start of reproduction, and decreases during reproduction to peak again in April, at the end of reproduction. Plasma sex hormones show trends similar to those found in previous studies. In autumn, PGE2 and androgen patterns are positively correlated, whereas the April PGE2 peak coincides with a drop in plasma androgens. In vivo and in vitro experiments suggest the causal relation between PGE2 and androgens. When injected in prereproductive newts or added to cultured testis in this period, PGE2 increases androgen production. An opposite in vivo and in vitro effect is obtained during reproduction. These findings suggest that PGE2 is involved in inducing the autumnal recovery of gonad and secondary sexual characters (through the stimulation of androgen production), and in terminating the breeding processes (through the inhibition of androgen production and/or clearance). Finally, captivity causes a decrease of plasma PGE2, androgens, and estradiol, a phenomenon quite common in captive vertebrates. © 1992 Wiley‐Liss, Inc.
Immunocytochemical analysis of the association of bovine oviduct‐specific glycoproteins with early embryos
Authors: Boice Melinda Lee , Mavrogianis Patricia A. , Murphy Clifford N. , Prather Randall S. , Day Billy N.
Published: June 2005

The bovine oviductal epithelium synthesizes and secretes a class of oviduct‐specific glycoproteins that is present in the luminal fluid when fertilization and early embryonic development occur. The objective of this study was to determine if these characterized glycoproteins become associated with oviductal embryos. Ovarian ova and oviductal embryos were recovered from super‐ovulated cows at 72 h after onset of estrus. Eggs were fixed in 3% paraformaldehyde‐1% gluteraldehyde and subsequently embedded in Lowicryl K4M. Sections (1 μm) were processed for peroxidase‐antiperoxidase immunocytochemistry. Immunolabeling was not detected in any region of ovarian ova. Oviductal embryos, regardless of cleavage stage, exhibited immunoperoxidase staining localized within their zona pellucidae. Sections (100 nm) obtained from a 4‐ and an 8‐cell embryo were also subjected to colloidal gold immunoelectron microscopy to determine conclusively the subcellular distribution of the oviduct‐specific glycoproteins. Gold particles were distributed uniformly throughout the width of the zona pellucida. Also, immunoreactivity was observed associated with flocculent material in the perivitelline space and with the vitelline membrane. These results indicate that the bovine oviduct‐specific secretory glycoproteins become associated with oviductal embryos. This association may be biologically important to the developing embryo. © 1992 Wiley‐Liss, Inc.
Ovarian stretch signals trigger volume increase in the magnocellular preoptic nuclear region in the brain of the catfish, Clarias batrachus (Linn.)
Authors: Deshmukh Makrand K. , Krishna N. S. Rama , Subhedar Nishikant
Published: June 2005

Intraovarian pressure of 10, 20, and 30 mm Hg magnitude was administered in the fish, Clarias batrachus, and the volume changes undergone by the magnocellular preoptic nucleus (NPO) were examined using serial brain sections of treated and sham‐treated fish. The treatment consistently resulted in statistically significant (P<0.001) increase in the volume of the NPO; a rise of up to 46.48% was observed in the paraventricular subdivision of the NPO following 20 mm Hg intraovarian pressure administration. The response was abolished following transection of the spinal cord. The results suggest the occurrence of an afferent pathway from the ovary capable of transducing stretch signals and conveying action potentials to the NPO via the spinal cord. The possibility that the pathway might serve as an afferent component in the spawning reflex is examined. © 1992 Wiley‐Liss, Inc.
Vitellogenesis level and induction of maturation in the ovary of the Blue Gourami Trichogaster trichopterus (Anabantidae, Pallas, 1770)
Authors: Degani Gad , Boker Rachel
Published: June 2005

The effectiveness of 17α‐hydroxyprogesterone (17‐P), 17α,20β‐dihydroxy‐4‐pregnen‐3‐one (17,20‐P), and carp gonadotropin (cGtH) in inducing germinal vesicle breakdown (GVBD) was examined in vitro in female blue gourami Trichogaster trichopterus (Pallas, 1770) as a model of multispawning, asynchronic fish. Induced GVBD was measured at three stages of ovary development: low (<25%), intermediate (≈30%), and high vitellogenesis (>45%).

The size of oocytes increased rapidly from the chromatin nucleolar stage to the stage of vitellogenesis, but little more thereafter. The effect of the hormones was to pass the oocytes from stage to stage, with very little effect on the size during maturation.

Only slight influence was detected on ovaries with a low percentage of vitellogenesis by treatment with 17‐P, 17,20‐P, cGtH, or any combination of these hormones.

In the intermediate percentage range, cGtH effected an increase in vitellogenesis, while cGtH in combination with 17‐P or 17,20‐P induced a low percentage of GVBD.

In ovaries with a high percentage of vitellogenesis (>45%), in vitro treatment with 100 ng/ml cGtH had little effect, 300 ng/ml cGtH significantly increased vitellogenesis, and 600 ng/ml induced a low level of GVBD. In vitro treatment with 300 ng/ml cGtH and various concentrations of 17‐P caused a significant increase in the percentage of oocytes in GVBD, and even induced ovulation. Various combinations of cGtH, 17‐P, and 17,20‐P significantly increased the percentage of oocytes in maturation, and also caused ovulation.

A model of the relationship between sexual behavior, ovary development, and control by MIS and GtH in this type of fish is discussed. © 1992 Wiley‐Liss, Inc.
Cholinesterase in the Cnidarians Velella velella (Hydrozoa: Syphonophora) and Actinia equina (Anthozoa: Actiniaria): A comparative study
Authors: Talesa Vincenzo , Principato Giovanni B. , Mangiabene Carla , Giovannini Elvio , Norton Scott J. , Rosi Gabriella
Published: June 2005

Soluble cholinesterases were purified from the cnidarians, Velella velella (Hydrozoa), and Actinia equina (Anthozoa), using 100,000g supernatants of total homogenates by affinity chromatography on a procainamide‐containing gel. An overall purification of 2,340‐ and 1,970‐fold, respectively, was achieved with an about 10% final yield. Both purified enzymes (relative molecular mass: 300 kDa, V. velella; 330 kDa, A. equina) seem to be tetrameric proteins consisting of four apparently identical or quite similar monomers. According to the values of kinetic constants, kcat and kcat/Km values, both enzymes are acetylcholinesterases. However, on the basis of kinetic and inhibition studies, the cholinesterase from A. equina shows a poor substrate affinity and an approximately 20‐fold lower catalytic efficiency in comparison with the enzyme from V. velella. These findings suggest in the former a less specific and relatively unspecialized conformation of the active site. Such different features are likely due to particular adaptive patterns of cnidarians, also involving their nervous system. © 1992 Wiley‐Liss, Inc.
Homeobox DNA polymorphisms (RFLPs) in subterranean mammals of the Spalax ehrenbergi superspecies in Israel: Patterns, correlates, and evolutionary significance
Authors: Nevo Eviatar , Ben‐Shlomo Rachel , Beiles Avigdor , Hart Charles P. , Ruddle Frank H.
Published: June 2005

Homeobox DNA polymorphisms (restriction fragment length polymorphisms, RFLPs) were first found in 13 individuals, and then in 121 subterranean mole rats of the Spalax ehrenbergi superspecies in Israel. Spalacidae are adapted morphologically to life underground apparently since Oligocene times, 30 million years ago. The superspecies S. ehrenbergi comprises four chromosomal species (2n = 52, 54, 58, and 60) displaying active speciation and dynamic adaptive radiation into four climatic regimes. A Hox‐1.1 and ‐1.5 polymorphism was found with EcoRI, where three of four individuals of the species 2n = 60 were lacking the diagnostic locus‐specific band present in all other nine individuals tested in the first stage. Next we found monomorphism in 121 animals in Hox‐2.1 digested with five six‐base recognition endonucleases (EcoRI, HindIII, BstEII, KpnI, BamHI, and one four‐base enzyme, TaqI). However, we found in the same 121 animals from 13 populations of the four species in Hox‐3.1 species‐specific TaqI polymorphism in two populations of 2n = 54, and HindIII polymorphism in five populations, three of 2n = 54 and two of 2n = 58. The homeobox polymorphisms found display significant correlations with the burrow microclimates of mole rats. Furthermore, they are significantly correlated primarily with diverse morphological variables, and secondarily with protein (allozyme) and DNA polymorphisms, but very little with physiological and behavioral variables. We suggest that in subterranean mole rats, the variation in microclimatic factors, particularly in more unpredictable xeric regions, may maintain genetic polymorphisms by diversifying selection in the developmental control homeobox genes Hox‐1.1, ‐1.5, and Hox‐3.1, affecting regulatory morphogenetic processes in evolution. By contrast, the Hox‐2.1 monomorphism suggests strong purifying selection for conservation across the superspecies over long periods of evolutionary times. © 1992 Wiley‐Liss, Inc.
Rapid proliferation of historecognition alleles in populations of a colonial ascidian
Authors: Yund Philip O. , Feldgarden Michael
Published: June 2005

Previous work on the distribution of historecognition alleles in botrylloid ascidians has revealed extensive polymorphism at this locus, but has yielded little information on the distribution of alleles among populations and the rate of allele proliferation within populations. We first present preliminary data on the genetics of historecognition in Botrylloides diegense, a West Coast native that was introduced to the East Coast in 1972. We then compare the distribution of alleles in 2 populations of different size in a Maine estuary. Finally, we compare the alleles in those 2 populations to the alleles in a population at Woods Hole, the site of the original introduction. Our results indicate that a small, peripheral population contains fewer alleles than a large population and suggest that alleles have proliferated rapidly since this species was introduced to the East Coast. The rapid proliferation of alleles reported here provides additional support for the hypothesis that historecognition systems are subject to frequency dependent selection in natural populations. © 1992 Wiley‐Liss, Inc.
Micromanipulation of cleaved embryos cultured in protein‐free medium: A mouse model for assisted hatching
Authors: Alikani Mina , Cohen Jacques
Published: June 2005

A mouse model for studying anomalies of human embryonic hatching following micromanipulation is proposed. Initiation and completion of mouse blastocyst hatching was severely impaired (34/292; 12% and 28/292; 10%, respectively) with protein deprivation, resembling the situation in human in vitro fertilization. Hatching ability was restored when an artificial gap was introduced in the zona pellucida by micromanipulation at the cleaved embryo stage. This enabled 77% (285/371) and 36% (134/371) of the embryos to initiate and complete hatching in protein‐free medium. No differences were found in overall cell counts between the two groups of embryos. Transfer of micromanipulated blastocysts to pseudopregnant females resulted in development of healthy fetuses. © 1992 Wiley‐Liss, Inc.
Differential processing of the two prolactins of the tilapia (Oreochromis mossambicus) in relation to environmental salinity
Authors: Borski Russell J. , Hansen Mette U. , Nishioka Richard S. , Grau E. Gordon
Published: June 2005

Prolactin (PRL) is thought to play a significant role in the freshwater (FW) adaptation of euryhaline teleost fishes, including the tilapia, Orechromis mossambicus. Two PRLs (tPRL188 and tPRL177) have been characterized in the anteriormost portion of the tilapia pituitary, the rostral pars distalis (RPD; Specker et al., '85a,b; Yamaguchi et al., '88). Our studies were undertaken to determine whether the in vivo RPD content of tPRL188 and tPRL177 varied with environmental salinity. To this end, tilapia were reared from the period of yolk‐sac absortion for 7 months or acclimated for 21 and 35 days in FW or seawater (SW). In a parallel study, we also examined whether the release of the 2 tilapia PRLs from the RPD of FW or SW tilapia might be differentially sensitive to changes in medium osmotic pressure during 18–20 hr incubations. In agreement with earlier work, we found that the smaller tPRL177 molecule was present in greater quantities in the RPD of FW tilapia compared to the content in RPD of SW fish. For the first time, we show here that the content of tPRL188, like that of tPRL177, is also significantly greater in the RPD of FW fish compared to the quantity in RPD of SW tilapia. Nevertheless, the relative content or ratio of the 2 PRLs in the pituitary was dependent on rearing salinity. Thus, the relative content or ratio of the larger tilapia PRL to smaller PRL (tPRL188/tPRL177) in the RPD of FW tilapia was significantly higher (1.5:1) than that seen in SW fish (0.75:1). This ratio was not altered after 18–20 hr in vitro incubations in hyposmotic or hyperosomtic medium, suggesting that the shift in ratios did not result from differential release by osmotic pressure. During 18–20 hr incubation in either hyposmotic or hyperosmotic medium, the RPD of FW tilapia released more of both forms of PRL than did the RPD of SW fish. Consistent with previous studies, reductions in medium osmotic pressure within the physiological range of the tilapia stimulated the release of botg tPRL188 and tPRL177 from RPD of FW fish over levels observed during exposure to hyperosmotic medium. We report here, for the first time, that the reduction of medium osmotic pressure also stimulates the release of both tPRL188 and tPRL177 from RPD of SW fish. Throughout the experiments we did not observe differences between the release of tPRL188 and tPRL177 under our incubation conditions. The transfer of FW‐reared fish to SW and vice versa for 49 days altered the ratio of the 2 PRLs (tPRL188/tPRL177) to that observed in the RPD of SW‐reared and FW‐reared fish, respectively. Overall, our studies indicate that the processing of the 2 PRLs may be differentially sensitive to environmental salinity. © 1992 Wiley‐Liss, Inc.
Changes in brain gonadotropin‐releasing hormone, plasma estradiol 17‐β, and progesterone during the final reproductive cycle of the female sea lamprey, Petromyzon marinus
Authors: Bolduc Thomas G. , Sower Stacia A.
Published: June 2005

Changes in ovarian morphology, brain gonadotropin‐releasing hormone (GnRH), plasma estradiol, and progesterone were examined during the 1988 and 1989 spawning migrations of the adult female sea lamprey, Petromyzon marinus. There were significant increases through time in brain GnRH (1989) and plasma estradiol (1988 and 1989), with progesterone levels fluctuating (1988 and 1989) during the freshwater phase of the spawning migrations. In 1989, brain GnRH and plasma estradiol levels gradually increased through time until just prior to spawning when levels decreased. During 1988, there were no significant changes in GnRH, which may reflect lower temperatures in that year. These data provide new information on brain GnRH during final maturational processes in the female sea lamprey. © 1992 Wiley‐Liss, Inc.
Limb amputation and heat shock induce changes in protein expression in the newt, Notophthalmus viridescens
Authors: Tam Ying K. , Vethamany‐Globus Swani , Globus Morton
Published: June 2005

Traditional limb regeneration studies have been focused on events transpiring during or subsequent to the 24–48 hour wound healing stage. In this study, amputation‐induced changes in limb protein expression were identified during the first few hours following amputation of the limb. These changes included the elevated expression of several amputation‐induced proteins (AIPs). Exposure of newts to a temperature of 37°C also resulted in teh enhanced synthesis of several heat shock proteins (HSPs) in similar molecular weight ranges. However, the amputation and heat shock responses differed in terms of the relative levels of induction of the various protein size classes. Furthermore, amputation resulted in the induction of an array of proteins that differed from those induced by heat shock. Unlike HSPs, AIPs were found to be synthesized exclusively in the forelimb tissue and were not seen in brain, liver, hindlimb, or tail tissues of forelimb‐amputated animals. However, AIP synthesis was not localized to limb tissue adjacent to the amputation site but rather was found at similar levels throughout the entire forelimb area. Moreover, in unilaterally amputated animals AIPs were found in both the amputated limb and the unamputated, contralateral limb. In addition to induced proteins, amputation also resulted in the suppression of several protein species. The latter occurred rapidly following amputation and was localized within the forelimb tissue immediately adjacent to the amputation site but not in proximal limb tissue. © 1992 Wiley‐Liss, Inc.
A comparison of tritiated vitellogenins prepared by in vivo and in vitro techniques for studies of ovarian uptake in fish
Authors: Nagler James J. , Idler David R. , So Ying P.
Published: June 2005

This study provides a comparison between serum vitellogenins (VGs), which have been radiolabelled with tritium (3H) using two different labelling methods, for ovarian uptake studies in fish. Purified VGs from winter flounder (Pseudopleuronectes americanus) and rainbow trout (Oncorhynchus mykiss) were radiolabelled in vitro following reaction with [3H]succinimidyl propionate which resulted in stable high specific activity [3H]propionyl‐VGs. Radiolabelled VGs were also prepared in vivo by injecting female winter flounder and rainbow trout with estradiol‐17β and [3H] amino acids intraperitoneally, and subsequently harvesting the serum and isolating the [3H]VGs. In winter flounder the ovarian uptake after a single intravenous injection of either [3H]propionyl‐VG or [3H]VG into female fish was determined after two weeks. Winter flounde VGs, radiolabelled either in vitro or in vivo, were similarly taken up by the ovary during early and mid phases of the annual vitellogenic cycle. It was demonstrated that both [3H]propionyl‐VG and [3H]VG were processed into a 280,000 relative molecular mass protein (i.e. lipovitellin). The small size of the vitellogenic winter flounder ovarian follicle precludes their use for in vitro culture, therefore an experiment was performed using rainbow trout ovarian follicles. Rainbow trout [3H]propionyl‐VG and [3H]VG were similarly incorporated by defolliculated ovarian follicles after 2, 6, and 12 hours of in vitro culture. © 1992 Wiley‐Liss, Inc.
Photoentrainment of the circadian rhythm in the electroretinogram of the crayfish and its dependence on the sinus gland
Authors: Moreno‐Sáenz Enrique , Fuentes‐Pardo Beatriz , Hernández‐Falcón Jesús
Published: June 2005

Sinus gland participation on the phase relationship between the circadian rhythms of the response to light (electroretinogram, ERG) of the visual photoreceptors in the crayfish was studied. Chronic ERG recordings were simultaneously obtained from both eyestalks in intact and sinus‐gland‐deprived animals during free‐running conditions and during the application of external periodic signals that consisted of 12 hr of light and 12 hr of darkness, or 12 hr of darkness and 12 hr of light, light regimens. It was found that the sinus glands are indispensable for preservation of the main characteristics of the circadian rhythm in the ERG and for the maintenance of a tight phase relationship between the rhythms of both eyes under free‐running conditions and during the application of the 2 kinds of light regimen. It is concluded that the sinus glands play a determining role in the processes that confer an internal temporal order on crayfish. © 1992 Wiley‐Liss, Inc.
Genetic and experimental studies on a new pigment mutant in Xenopus laevis
Authors: Droin Anne
Published: June 2005

White lethal (wl) is a recessive mutation affecting the differentiation of the three types of chromatophores in Xenopus laevis and eventually leading to the death of the mutants around stage 50. Melanophores appear at st. 33 but differentiate abnormally, remaining pale grey, and do not proliferate after st. 41. The rare xanthophores present contain only a few differentiated pterinosomes, and the iridophores consist of noniridescent white dots. When the albino gene (ap) is combined with wl, melanophores do not differentiate. Reciprocal heterotopic and orthotopic trunk neural crest grafts have shown that the defect is intrinsic to the neural crest cells but is not due, in the case of melanophores, to a tyrosinase deficiency as revealed by the dopa reaction. The mode of action of the gene, the abnormal pattern, and lethality are discussed. © 1992 Wiley‐Liss, Inc.
Protein kinase C modulators influence meiosis kinetics but not fertilizability of mouse oocytes
Authors: Lefèvre Brigitte , Pesty Arlette , Koziak Katarzyna , Testart Jacques
Published: June 2005

The role of protein kinase C (PKC) in the successive steps of mouse oocyte meiotic process was investigated. We have used either OAG, an analog of diacylglycerol, or mezerein, a nonphorbol ester diterpene, less tumor promoting than phorbol esters, as PKC activators, and staurosporine as PKC inhibitor. Cumulus‐free oocytes were cultured in minimum essential medium with each of these PKC modulators and maturation stages were screened every two hours until the end of the process. Both PKC activators prevented GVBD at each tested dose for 4 hr (OAG) and 8 hr (mezerein), and decreased the frequencies of PB oocytes. The inhibitory effects of both activators were dose dependent and reversible. The addition of OAG to the culture medium after GVBD occurence (i.e., after 4 hrs) did not affect PB extrusion whereas similar addition of mezerein significantly decreased the frequency of PB oocytes. Inhibition of PKC by staurosporine accelerated GVBD and increased the frequency of PB extrusion. When staurosporine was added after GVBD, PB extrusion occurred earlier but PB oocyte frequency was not increased. Fertilizability was not affected when oocyte maturation occurred in the presence of any of these substances despite the delay in maturation process. These results clearly indicate that the PKC pathway in involved in mouse oocyte meiotic process: activation of the enzyme would arrest meiotic process whereas its inhibition would participate in meiosis induction. © 1992 Wiley‐Liss, Inc.
Culture of postimplantation rat embryos in rabbit serum for the identification of the growth factor in fractionated rat serum
Authors: Usami Makoto , Nakaura Shinsuke , Kawashima Kunio , Tanaka Satoru , Takanaka Akira
Published: June 2005

The growth factor for postimplantation rat embryos was investigated on the basis of the serum species‐specificity in supporting embryonic development in culture. We used rabbit serum as a basal medium for the culture of head‐fold stage rat embryos, and examined the effects of various fractions of rat serum on their development. In rabbit serum alone, rat embryos developed poorly. With the rat serum ultrafiltrate of molecular weight (MW) < 300,000, embryonic development improved, but not with the ultrafiltrate of MW < 100,000. With dialyzed rat serum or the globulin fraction of rat serum, embryonic development improved, but the albumin fraction had no effect. It was concluded from these results that some macromolecular growth factor for cultured postimplantation rat embryos was present in the globulin fraction of rat serum. The molecular weight of this growth factor was estimated to be between 65,000 and 300,000. Rabbit serum was considered to be suitable as a medium for the identification of this growth factor. © 1992 Wiley‐Liss, Inc.
The ionophore‐induced acrosome reaction differs structurally from the spontaneous acrosome reaction
Authors: Watson P. F. , Plummer J. M. , Jones P. S.
Published: June 2005

The ultrastructure of the spontaneous acrosome reaction in ram spermatozoa has been compared with that induced by the ionophore, A23187. The spontaneous event was dependent on incubation for 4 h, on the temperature, and on dilution. Apart from the more rapid occurrence of the ionophore‐induced event, the mean diameter and distribution of vesicle size was also different. The ionophore‐induced vesicles were larger, more irregular, and heterogeneous in size compared with those occuring in the spontaneous acrosome reaction (average diameter 84 nm vs. 60 nm in the spontaneous acrosome reaction). These observations are interpreted in relation to capacitation. © 1992 Wiley‐Liss, Inc.
Secretion of prostaglandin F2α and E2 in vitro by the uterus of the American alligator (Alligator mississippiensis)
Authors: Dubois Daniel H. , Guillette Louis J.
Published: June 2005

This study determined whether uterine tissue of alligators produce prostaglandins F2α (PGF) and E2 (PGE) and examined the relationship between secretion of prostaglandins and reproductive stage. Uterine tissue from alligators (n = 8) was incubated in the presence of arachidonic acid (AA), banamine (B), arginine vasotocin (AVT), AA + AVT or incubation medium alone. Aliquots of the culture medium were collected at 0, 30, 60, and 90 min and at 24 h of culture. Secretion of PGF was not detected from uterine tissue collected from gravid alligators, whereas non‐gravid and post‐oviposition alligators secreted appreciable amounts of PGF. The addition of AA to uterine tissue from non‐gravid alligators increased secretion of PGF (P < 0.05), whereas AVT had no effect. Addition of AA or AVT decreased secretion of PGF and PGE by uterine tissue from post‐oviposition alligators (P < 0.05). Secretion of PGF and PGE by uterine tissue was greater from post‐oviposition than from non‐gravid and gravid alligators. Secretion of PGE from uterine tissue of non‐gravid alligators was not altered by AA or AVT. However, secretion of PGE from uterine tissue from gravid alligators increased in the presence of AVT and decreased when incubated with AA + AVT. Arachidonic acid alone did not significantly alter secretion of PGE in this group. This study demonstrated that uteri of alligators secrete PGF and PGE and production is related to reproductive status. © 1992 Wiley‐Liss, Inc.
Assembly and disassembly of axonal microtubules of the toad Xenopus laevis under the effect of temperature
Authors: Alvarez Jaime , Fadić Ricardo
Published: June 2005

In toads Xenopus laevis living at 11° (winter), the microtubular density of 4‐μm myelinated axons of lumbosacral nerves was assessed with the electron microscope. In controls, the density was 11.2 microtubules/μm2. In nerves incubated at 0°, microtubules decreased following a simple exponential curve with a half time of 4.7 min (k = 0.149 min−1); residual microtubules were 4.5%. After rewarming, the full complement of microtubules reappeared within 60 min. In steady state, the microtubular density exhibited a linear relationship with temperature (range: 0–22°;slope 0.94 microtubules/μm2 per degree; r, 0.96). After heating the nerve by 11° above the physiological temperature, microtubules increased by 83%, whereby the pool of unpolymerized tubulin was at least 2.7 mg/ml of axoplasm. A seasonal variation of the microtubular density was observed which accorded with the environmental temperature. The macroscopic kinetics of microtubule disassembly in the axoplasm is similar to that reported for purified tubulin but that of assembly is slower. Microtubules of peripheral axons of Xenopus are cold‐labile and vary during the annual cycle. © 1992 Wiley‐Liss, Inc.
Allogeneic recognition and sex differentiation in chimeras of the freshwater sponge Ephydatia muelleri
Authors: Mukai Hideo
Published: June 2005

Allogeneic recognition and sex differentiation in Ephydatia muelleri were studied with two types of chimeric sponges, mixed and unmixed. Using gemmules of nine original sponges (stocks) collected in a pond, chimeras were prepared in the laboratory. Subsequently, the chimeric sponges were transferred to and cultured in the pond of their origin. They were observed macroscopically and histologically. The unmixed chimeras consisted of halves of different stocks. All unmixed chimeras grew as a continuous sheet for more than 10 days. Then, some of them showed a demarcation line at the boundary of the paired partners. Histologically, the demarcation line of a grown chimera was detected as a gap, on either side of which a narrow zone of tissue was more or less disorganized, containing no sexual elements. The combinations of stocks showing a demarcation line in unmixed chimeras are called incompatible, and those with no demarcation line compatible. Five histocompatibility strains were distinguished among the nine stocks used. Some interstrain combinations were compatible. In the chimeric individuals, the putative male region contained spermatic cysts, and the putative female region contained oocytes and embryos. In compatible heterosexual chimeras, male and female sexual elements were sometimes more or less separated but often were intermingled in the boundary zone. Gender seems to be genetically determined. The mixed chimeras were produced from randomly mixed gemmules of different stocks. Mixed chimeras of heterosexual combinations gave the following results. Many chimeras of the incompatible combinations showed a few to several irregular demarcation lines and contained both male and female sexual elements. Some incompatible mixed chimeras, however, did not show a demarcation line and contained only male sexual elements. Some compatible mixed chimeras contained both male and female sexual elements, but the male area was usually larger than the female area. Moreover, some compatible mixed chimeras contained only male sexual elements. Thus, a dominance of the male over the female was revealed in the mixed chimeras. A replacement of female tissues by male tissues during a short period following gemmule hatching is assumed. This may be considered an example of somatic cell parasitism. © 1992 Wiley‐Liss, Inc.
Effect of air exposure on nitrogen metabolism in the crab Cancer pagurus
Authors: Regnault Michèle
Published: June 2005

In C. pagurus exposed to air for 18h, blood ammonia content decreased within the 2 first hours, then increased at a relatively constant rate (25 μM/h); blood urate content increased at a lower rate (10 μM/h) and a classical blood acidosis was observed. In the cheliped muscle, a transient 22% decrease in GDH activity for ammonia formation and a 48% increase in GDH activity in the reverse reaction (glutamate synthesis) occurred following 6 and 12 h of emersion, respectively. Changes in LDH activity, used as an indicator of anaerobic potential of muscle, were not observed, except for an 18% increase in crabs exposed to air for 24 h.

The increase in blood urate content, not known as a response to emersion in decapods, appeared to be different from that observed in response to hypoxia. The relatively low blood ammonia overload and the GDH increased activity for glutamate synthesis suggested that part of the produced ammonia was stored under a bound from in some tissues. The response of C. pagurus to air exposure is discussed on account of the Storey and Storey ('90) theory. © 1992 Wiley‐Liss, Inc.
Histochemical heterogeneity of fibers in the abdominal superficial flexor muscles of the Norway lobster, Nephrops norvegicus (L.)
Authors: Fowler William S. , Neil Douglas M.
Published: June 2005

The superficial flexor muscle in the abdomen of the Norway lobster Nephrops norvegicus (L.), comprises medial and lateral bundles with distinct fiber type composition. Fibers of the medial bundle have long sarcomeres (>9 μm) and a thick fringe of subsarcolemmal mitochondria. In histochemical tests they have a low total myofibrillar ATPase activity, a pH‐stable isoform of myosin ATPase, and a high level of oxidative enzyme activity. A few fibers of the lateral bundle also display these morphological and histochemical properties. However, the majority of lateral fibers have shorter sarcomeres (<8 μm), no subsarcolemmal mitochondria, but a well‐developed tubular system. They also have a higher total myofibrillar ATPase activity, a pH‐labile isoform of myosin ATPase, and a low level of oxidative enzyme activity. The heterogeneous pattern of different fiber types in the lateral bundle of this muscle is similar but not identical in the different abdominal segments and in different individuals. © 1992 Wiley‐Liss, Inc.
Cryopreservation of Atlantic croaker spermatozoa: Evaluation of morphological changes
Authors: Gwo Jin‐Chywan , Arnold Connie R.
Published: June 2005

The spermatozoon of the Atlantic croaker (Micropogonias undulatus) is a primitive type in that it lacks an acrosome. The kidney‐shaped head has a diameter of about 1.5 μm and is occupied by a granular and electron‐dense nucleus. The short midpiece contains 3 spherical mitochondria and encircles the basal body of the flagellum but is separated from it. The flagellum consists of the typical 9 + 2 axoneme and surrounding plasma membrane but lacks a lateral ridge. Spermatozoa of Atlantic croaker diluted in either NaCl or sodium citrate solutions with or without DMSO were examined with the electron microscope before freezing in liquid nitrogen and after thawing. Damage following cryopreservation appeared to be greater to the mitochondria, plasma membrane, and 9 + 2 axoneme than to the nucleus. The incidence of postthaw damage in spermatozoa diluted with NaCl solutions containing DMSO was remarkably lower than that with either pure NaCl solutions, pure sodium citrate solutions, or sodium citrate solutions containing DMSO. © 1992 Wiley‐Liss, Inc.
Arginine vasotocin concentrations in the supraoptic nucleus of the lizard Anolis carolinensis are associated with reproductive state but not oviposition
Authors: Propper Catherine R. , Jones Richard E. , Dores Robert M. , Lopez Kristin H.
Published: June 2005

Arginine vasotocin (AVT) is a neuropeptide involved in reproductive function in many nonmammalian vertebrates. We determined brain and plasma AVT concentrations during the estrous cycle and oviposition in the lizard Anolis carolinensis. There were no differences in AVT concentrations in the plasma or any brain region during the ovipositional sequence. However, we found that females with an egg in each oviduct and a large pre‐ovulatory follicle (diameter > 4.5 mm) in oneovary had significantly higher AVT concentrations in the supraoptic nucleus (SON) of the hypothalamus than did females with small pre‐ovulatory follicles in both ovaries. In a second study, females with an egg in each oviduct and a large pre‐ovulatory follicle had significantly greater AVT concentrations in the SON than females with only one oviductal egg and a large pre‐ovulatory follicle or females with an egg in each oviduct and a small pre‐ovulatory follicle in each ovary. Concentrations of AVT in other brain regions and in the plasma did not differ among these groups. Changes in steroid profiles during estrous and/or direct neural communication between the uterus, ovary, and brain may account for the changes in AVT concentrations seen in the supraoptic nucleus during the estrous cycle of Anolis carolinensis. © 1992 Wiley‐Liss, Inc.
Lack of coupling between onset of giant transformation and genome endoreduplication in the mural trophectoderm of the mouse blastocyst
Authors: Gardner R. L. , Davies T. J.
Published: June 2005

Prominent among the various types of cell that differentiate from the trophectoderm of the mouse blastocyst are trophoblastic giant cells. Repeated endoreduplication of the genome accompanies the growth of these cells, which have been shown to be polytene rather than polyploid. Early stages in giant transformation have been examined, mainly in the mural trophectoderm of the implanting blastocyst which gives rise to the primary trophoblastic giant cells. One confusing issue is whether these early stages include the onset of endoreduplication of the genome. This issue has been addressed in the present study by comparing the DNA content of nuclei in isolated trophectoderm and ICM tissue rather than, as previously, by relating measurements on air‐dry preparations of entire blastocysts to those of adult liver. The results, particularly those from delayed and reactivated blastocysts, show that genome endoreduplication is not an obligatory early event in the transformation of mural trophectoderm cells. © 1993 Wiley‐Liss, Inc.
Production and characterization of monoclonal antibodies specific for bovine oviductal glycoproteins
Authors: Abe Hiroyuki , Numazawa Chikako , Abe Miki , Hoshi Hiroyoshi , Oikawa Taneaki
Published: June 2005

Four monoclonal antibodies (MAbs) were produced in rat cells against materials obtained from the bovine oviduct. The MAbs (1H10, 2A4, 2C5, and 1B12) reacted strongly with the oviductal epithelium of cows in the follicular phase. An immunohistochemical study demonstrated that each of the MAbs bound strongly to the supranuclear cytoplasm of epithelial cells of the oviduct, but not of the stromal cells. Antigens that reacted with the MAbs were characterized by immunoblotting analysis of proteins after fractionation by SDS‐PAGE under reducing conditions of oviductal flushings obtained from cows at estrus. All MAbs strongly stained a band of protein with a molecular weight (MW) of 85–97 kD. MAb 1H10 also reacted with the minor band of a 55‐kD protein. Similar antigens were not detected in uterine flushings, follicular fluid, and serum. No specific immunohistochemical reactivity with the MAbs was observed with other tissues from the reproductive tract and with nonreproductive tissues. The immunohistochemical reactions were completely eliminated by pretreatment of tissues with trypsin, but not with periodic acid, results that suggest that the antigenic determinants that react with the MAbs were proteinaceous rather than carbohydrate. We have thus established clones that produce 4 MAbs that are specific for oviduct‐specific glycoproteins of the cow. © 1993 Wiley‐Liss, Inc.
Retinoic acid, cortisone, or thyroxine suppresses the mutant phenotype of the eyelid development mutation, lgMI, in mice
Authors: Juriloff D. M. , Harris M. J.
Published: June 2005

The development of the mammalian eyelid is one of the last major morphogenetic events during prenatal development. The eyelids originate as outgrowths of epithelium and mesenchyme above and below the eye; they grow and flatten across the eyes, and meet and fuse firmly but temporarily until several days after birth in mice. In mouse lidgap mutants, eyelid development fails. Previously, we have shown that normal eyelid development can be induced in lidgap mutants by maternal treatment with cortisone or thyroxine. These hormones have been reported to interact with members of a receptor superfamily, and their response elements have been shown to induce transcription of hormone‐regulated genes; retinoic acid also interacts with members of this superfamily. The purposes of our study were to examine the joint effect of thyroxine and cortisone on induced eyelid development in lidgap‐Miller mutant fetuses (lgMI/lgM1), to test for synergism, and also to test whether retinoic acid also induces eyelid development in this mutant. We found that the combined effect of thyroxine and cortisone was significantly greater than that of either hormone alone, but that the dose‐response slopes (log dose, probit scale) for eyelid development induced by cortisone alone or by cortisone preceded by 0.1 mg thyroxine were parallel, suggesting that their action is additive, not synergistic. We found that retinoic acid administered on day 14 of gestation induced eyelid development in lgMI/lgM1 mutant fetuses, with a significant dose response and ED50 of 24 ± 6 mg/kg. The response was treatment‐time dependent, with optimal responses after day 14 or 11 treatment. We conclude that the overlapping genetic regulatory network that orchestrates eyelid development can utilize at least 3 of the hormones that interact with members of the steroid receptor superfamily and its response elements. © 1993 Wiley‐Liss, Inc.
Differences in chromatin condensation during spermiogenesis in two species of fish with distinct protamines
Authors: Saperas N. , Ribes E. , Buesa C. , García‐Hegart F. , Chiva M.
Published: June 2005

The sperm cells of Mullus surmuletus (family Mullidae, order Perciformes) and Dicentrarchus labrax (family Percichthyidae, order Perciformes) belong respectively to “type I” and “type II” spermiogenesis categorized by Mattei ('70). The protein content in their sperm nuclei consists of two histone‐like proteins (Mullus surmuletus) and one typical protamine (D. labrax). In order to correlate the molecular characteristics of these proteins with their function, we have analyzed the molecules in detail and studied at the ultrastructural level the condensation of chromatin during the spermiogenesis in both species. D. labrax has a true protamine of 34 amino acid residues and its sequence (PR4QASRPVR5TR2STAER5V2R4) contains four arginine clusters. The sperm proteins of M. surmuletus contain 110 and 115 amino acid residues and, by their composition (23–24% Lys, 21–22% Arg, 11–12% Ala), they are similar to protamine‐like molecules from sperm of molluscs. During the spermiogenesis of D. labrax, chromatin condensation progresses from small fibro‐granular structures (25 ± 5 nm in diameter), to larger granules (150 ± 50 nm diameter). M. surmuletus accumulates 25 ± 5 nm diameter structures in the basal pole of the nucleus; these structures grow till they reach a diameter of 50 ± 10 nm and finally go through a process of fusion that changes the condensation of chromatin in sperm nuclei, acquiring a homogeneous aspect.

These observations show that during spermiogenesis in the studied types, the last stages of chromatin condensation are dependent on the type of nuclear proteins. © 1993 Wiley‐Liss, Inc.
Proteins Of crustacean exoskeleton II: Immunological evidence for their relatedness to cuticular proteins of two insects
Authors: Kumari S. Sindhu , Skinner Dorothy M.
Published: June 2005

The exoskeletons of crustaceans and cuticles of insects are characterized by an abundance of proteins with acidic pIs and Mrs 31 kDa or smaller. Immunochemical data described here further demonstrate the similarities of such proteins among representatives of these two major classes of Arthropoda. Proteins extracted from the four individual layers of the exoskeletons of Bermuda land crabs Gecarcinus lateralis at different stages of the intermolt cycle and from exuviae, the partially degraded old exoskeleton that is cast at ecdysis, were analyzed on Western blots with polyspecific polyclonal antibodies against either larval cuticular proteins (anti‐LCP) or pupal cuticular proteins (anti‐PCP) of the tobacco hornworm Manduca sexta, or against two pairs of larval cuticular proteins from third instar larvae (anti‐L3CPs) of Drosophila melanogaster. M. sexta anti‐LCP cross‐reacted with many of the crab proteins extracted at all stages of the intermolt cycle. It reacted with more high Mr proteins from late proecdysial exoskeleton and exuviae than with such proteins from anecdysial or early proecdysial exoskeletons, probably because the larger Mr proteins are enriched when the lower Mr proteins are degraded during proecdysis. M. sexta anti‐PCP cross‐reacted hardly at all with the crab proteins. Both D. melanogaster anti‐L3CPs cross‐reacted with crab epicuticular proteins at all stages of the intermolt cycle and from exuviae. Anti‐L3CP 3 + 4 reacted even more intensely and with many more proteins from the three inner layers of the exoskeleton than did anti‐L3CP 1+2. Controls included 2D gels with rabbit anti‐ovalbumin to detect glycoproteins containing mannose and N‐acetyl‐glucosamine; it cross‐reacted with only one protein in membranous layer of an anecdysial crab, while rabbit anti‐fluorescein reacted with none. By contrast, the intensity and specificity of the cross‐reactions of crab exoskeletal proteins with antibodies against cuticular proteins of members of two orders of insects suggest that at least some cuticular proteins in the two arthropod Classes, Crustacea and Insecta, are evolutionarily conserved. Published 1993 Wiley‐Liss, Inc.
Metabolic adaptations by the leech Nephelopsis obscura during long‐term anoxia and recovery
Authors: Reddy D. C. , Davies Ronald W.
Published: June 2005

Metabolic adaptations to long‐term (40 day) anoxia were determined in two size groups (small and large) of the freshwater leech Nephelopsis obscura. Neither size group accumulated the lactic acid during anoxia; rather succinate and alanine were the major end products. Glycogen and amino acids were the primary energy reserves utilized with lipid also utilized by small N. obscura. After 40 days of anoxia glycolytic flux was reduced by 99.8% in small and 99.7% in large N. obscura. Cellular energy status adenosine triphosphate/adenosine diphosphate (ATP/ADP) also declined significantly in small (79%) and large (69%) leeches. After return to normoxia the energy charge in small N. obscura was restored within 6 hours and glycogen, malate, succinate, alanine, and aspartate restored within 24 hours. Large N. obscura utilized lower proportions of their energy reserves than small N. obscura. © 1993 Wiley‐Liss, Inc.
Mapping of the chicken N‐CAM gene and a myosin heavy chain gene: Avian microchromosomes are not genetically inert reserves of DNA
Authors: Dominguez‐Steglich Marina , Robbins Jeffrey , Schmid Michael
Published: June 2005

Physical mapping of the chicken neural cell adhesion molecule gene and of a chicken myosin fast‐white heavy chain gene via in situ hybridization has assigned both loci to different‐sized microchromosomes in this species. Two genomic cloned chicken DNA probes of 16 kb (λ cN6) and 15 kb (DCM 11), respectively, were biotin labeled for fluorescent detection of the genes. The implications derived from these results, together with further data just now beginning to accumulate regarding the genetic content of avian microchromosomes, confirm an unexpectedly active role for these minute chromosomes. © 1993 Wiley‐Liss, Inc.
The role of organic osmolytes in osmoregulation: From bacteria to mammals
Authors: Kinne Rolf K. H.
Published: June 2005

Cells of marine species are known to establish osmotic balance with their environment by adjusting the concentrations of organic osmolytes rather than inorganic osmolytes such as sodium, potassium, and chloride. These organic osmolytes fall into three classes: polyhydric alcohols such as sorbitol, amino acids and amino acid derivatives, and urea and trimethylamines. Substantial evidence is available for a central role of each of these classes in osmoregulation in marine species. In this chapter information on the importance of organic osmolytes is extended to a study of isolated mammalian kidney cells. The intracellular concentration of organic osmolytes in these cells responds dramatically to changes in the osmotic environment. The release of sorbitol following hypoosmotic exposure appears to be triggered by calcium, possibly via a mechanism involving membrane recycling. The summarized experiments provide a basis for further work in marine species. © 1993 Wiley‐Liss, Inc.