bluuebunny/crossref_metadata_2025 huggingface dataset:
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

The 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

Administration 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

Injection 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

Cycles 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

In 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

A 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

Slugs (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

The 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.
Free amino acids and cell volume regulation in the elasmobranch, Raja erinacea
Authors: Goldstein Leon
Published: June 2005

Free amino acids comprise a significant fraction of the total intracellular osmolality in skate tissues. The high amino acid concentrations are maintained by active, Na+‐dependent transport systems in the cell membranes. Following transfer to a hypo‐osmotic environment (dilute seawater) cellular concentrations of free amino acids are reduced mainly as a result of increased rates of outflux but decreased rate of influx can also play a role. Metabolism (oxidation and synthesis) does not appear to play a direct role in the modulation of free amino acid concentrations in skeletal muscle cells and erythrocytes. However, continued release of free amino acids from these cells during hypo‐osmotic stress is dependent on the ability of liver and kidney to either oxidize (β‐alanine, sarcosine) or excrete (taurine) amino acids at accelerated rates. A scheme for the overall modulation of cellular free amino acids in skate tissues by a combination of membrane transport, metabolism, and excretion is presented.
Circadian rhythm of nonpineal extraretinal photosensitivity in a teleost fish, the lake chub, Couesius plumbeus
Authors: Kavaliers Martin
Published: June 2005

Lake chub, Couesius plumbeus, displayed a diurnal rhythm of nonpineal extraretinal photosensitivity under laboratory light‐dark cycles. There was a bimodal pattern in the threshold intensity (energy fluence rate) for iniating extraretinally mediated photoresponses. Significantly greater intensitites were required in the scotophase than in the photophase of a 12‐hour‐light:12‐hour‐dark cycle. Maximal sensitivity was at the light‐dark and dark‐light transitions. Under constant darkness this pattern continued as a free‐running circadian rhythm of nonpineal extraretinal photosensitivity. The pineal organ, which is directly photosensitive and involved in the control of circadian rhythms in teleost fishes, is not essential for either the generation or expression of this circadian rhythm.
Extraocular photoentrainment of the circadian locomotor rhythm of the garden slug Limax
Authors: Beiswanger Christine M. , Sokolove Phillip G. , Prior David J.
Published: June 2005

Garden slugs (Limax maximus and Limax flavus) exhibit a circadian locomotor rhythm which persists in constant darkness or light and in constant temperature with a period of approximately 24 hours, entrains to lightdark cycles (LD 12:12 or LD 16:8), and can be phase shifted by changes in the LD cycle. Results of experiments comparing the locomotor activity of blinded slugs and unoperated control animals indicate that the eyes are not necessary for either maintenance of rhythmicity or for LD entrainment. In DD, locomotor activity of blinded and control animals is robust, and the active period in a freerun projects back to the dark phase of the previous light‐dark cycle. Blinded animals remain entrainable to white‐light LD cycles and are able to follow a 6 or 12 hour phase shift. However, eyeless animals do not entrain to LD cycles of wavelengths greater than about 600 nm, whereas intact animals entrain without difficulty. In additon, there is an approximately 2‐hour increase in the phase angle difference of blinded animals compared to either sham or unoperated controls. These observations suggest that the eyes provide photic input to the slug circadian system, even though they are not essential components of the circadian oscillator that controls locomotor activity.
Wound healing in the imaginal discs of Drosophila II. Transmission electron microscopy of normal and healing wing discs
Authors: Reinhardt Christoph A. , Bryant Peter J.
Published: June 2005

The normal elements of the cell surface and the cytoskeleton of imaginal wing disc cells in third‐instar larvae of Drosophila melanogaster are described. This serves as a background for understanding the process of wound healing after experimentally cutting the two disc epithelia (columnar epithelium and peripodial membrane).

The cells of both epithelial layers display microvilli at the apical surface, and there is a microvillar ridge at the periphery of each cell. The lateral cell surfaces display zonulae adhaerens, gap junctions, and septate junctions in characteristic patterns. A terminal web of 60–70‐Å microfilaments is located in the apical cell periphery, extends into the microvillar ridge, and is connected with the zonula adhaerens and probably also with the underlying belt of microtubules.

Immediately after an incision is made in a normal disc, the two wound edges move apart to form a gape of about 45°. This fast wounding reaction is reversibly inhibited by treatment with cytochalasin B (0.5 μg/ml), suggesting that the wounding reaction is achieved by actinlike microfilaments. Initial wound closure results in an apposition of the columnar epithelium and the peripodial membrane (heterotypic contacts). Close (10–20 nm) heterotypic membrane contacts are found beginning at 12 hours after wounding, but cell junctions are not observed at such contact sites.

Within 24 hours after wounding, the first focal cell membrane contacts are made between cells of corresponding epithelial types across the wound (homotypic contacts), at which time the heterotypic contacts are broken. At the time of epithelial healing, the wound surfaces shorten (“wound contraction”), and this is associated with cell‐shape changes within the epithelial cells along the wound. Within 48 hours after wounding, homotypic cell junctions and nonjunctional membrane contacts are fully reestablished, and wound healing is completed.

We propose that the homotypic contacts between cells of the columnar epithelium are involved in the intercellular interactions controlling pattern regulation in the imaginal wing disc.
The hatching enzyme of Fundulus heteroclitus
Authors: DiMichele Leonard , Taylor Malcolm H. , Singleton Rivers
Published: June 2005

The chorionase (hatching enzyme) of Fundulus heteroclitus digests the chorion by producing water soluble peptide fragments. The chorion may be labeled with 14C‐iodoacetamide so that the soluble products of digestion are also labeled. We used this labeled substrate as the basis for a quantitative assay for chorionase. Chorionase was found to be quite stable at temperatures below 30°C and had a Q10 of 2.2 between 15 and 30°C. The pH optimum for enzymatic activity was between pH 8.0 and pH 8.5, and an ionic strength optimum was found between 0.1M and 0.2M. The enzyme was inhibited at ionic strengths similar to those found in sea water. Chorionase was also inhibited by divalent cations, EDTA, and PMSF. These results suggest that divalent cations are necessary for activity even though they are inhibitory at concentrations above 10mM.
Inhibition of in vitro fertilization of mouse eggs: 3‐quinuclidinyl benzilate specifically blocks penetration of zonae pellucidae by mouse spermatozoa
Authors: Florman Harvey M. , Storey Bayard T.
Published: June 2005

The fertilization in vitro of mouse eggs with intact zonae pellucidae by mouse cauda epididymal spermatozoa was inhibited in a concentration‐dependent fashion by 3‐quinuclidinyl benzilate (QNB), normally used as a specific antagonist for the muscarinic class of cholinergic receptors. Inhibition was observed with both cumulus‐intact and cumulus‐free preparations. QNB at 50 μM inhibited fertilization of cumulus‐free eggs by greater than 90% but had no effect on the fertilization of zona‐free eggs. At this concentration, QNB had no adverse effect on sperm motility, nor did it prevent binding of spermatozoa to the zona pellucida. The inhibitory effects of QNB were fully reversible. QNB is therefore a useful specific inhibitor of zona penetration. Spermatozoa in the in vitro fertilization medium bound QNB with a concentration dependence which matched that of the inhibition of fertilization. This binding was saturable and corresponded to 700 pmole/107 cells with KD = 10 μM. The in vitro fertilization medium contains 2% (w/v) bovine serum albumin (BSA) which also binds QNB according to the mass action law. The large amount of QNB bound to sperm in this medium appears to be QNB binding to BSA adsorbed on the sperm cell surface: these spermatozoa bind QNB specifically in the absence of BSA with a saturable capacity of only 70 fmole/107 cells with KD = 5 nM. Calculation of the distribution of QNB between BSA binding sites and sperm surface binding sites in the in vitro fertilization medium indicates that the specific sperm sites become saturated with the same concentration dependence as inhibition of fertilization. However, the dissociation rate of QNB from sperm in both the presence and absence of BSA is too rapid to permit confirmation of these sites as the locus of the inhibitory effect; this locus remains to be clarified.
The fertilization performance in vivo of rabbit spermatozoa capacitated in vitro
Authors: Viriyapanich P. , Bedford J. M.
Published: June 2005

Although mammalian spermatozoa can be capacitated in vitro appropriately for the accomplishment of fertilization in vitro, it has not been established whether such spermatozoa can fertilize immediately in the Fallopian tube nor whether their fertilizing ability is comparable to that of spermatozoa capacitated in vivo. Rabbit spermatozoa treated here in a way reported to capacitate them for fertilization in vitro (20 min in high ionic strength medium (HIS) of 380 mOsm/kg at 37°C) could not penetrate eggs in the Fallopian tube unless allowed a considerable time for further capacitation in the female tract. Thus, while it may initiate the events of capacitation, HIS treatment clearly does not complete the process. Spermatozoa cultured for 12 h under another set of defined conditions (BSA‐free medium +20% serum under oil equilibrated with 5% CO2 + 8% O2 at 37°C) did fertilize eggs in 7 of 14 trials, however, when inseminated 12–15 h post‐hCG. Therefore capacitation that allows fertilization in vivo soon after insemination can be achieved in at least some spermatozoa, largely and perhaps entirely in the absence of factors from the female tract. Nonetheless, the performance of the 12h in vitro spermatozoa (29% of 131 eggs fertilized: 0.3 perivitelline spermatozoa/egg) compared poorly with that of 10 times fewer uterine spermatozoa in the contralateral oviduct (81% of 43 eggs fertilized: 15 perivitelline spermatozoa/egg). Moreover, in a final series, 12 h in vitro capacitated spermatozoa failed to compete directly for ova if inseminated together with many fewer labeled uterine spermatozoa, even though they fertilized significant numbers when inseminated alone into the contralateral oviduct.

Current in vivo and in vitro fertilization systems for the assay of rabbit sperm capacitation are not entirely comparable because the penetrable life of rabbit ova is short in the Fallopian tube but prolonged in culture. Since fully capacitated spermatozoa begin to penetrate eggs almost immediately, assay of the capacitation status of spermatozoa of the rabbit or indeed of other species might best be evaluated within about 3 hours of gamete mixing. Such a limitation on the time allowed for sperm‐egg interaction in capacitation assays would minimize the possibility for completion of capacitation by factors present in the fertilization assay system.
Inhibition of two homeotic mutants of Drosophila by 5‐bromodeoxyuridine and fluorouracil
Authors: Ibars George C. , Selick Harold E. , Kauffman Stuart A.
Published: June 2005

Nasobemia (Ns) and spineless‐aristapedia (ssa40a) are dominant and recessive homeotic mutants of Drosophila which convert parts of the antenna to leg structures. Exposure of Ns and ssa40a larvae to half‐lethal concentrations of 5‐bromodeoxyuridine (BUdR) and flourouracil (FU) together or separately during the presumptive time of gene action suppresses the expressivity and penetrance of the mutants.
Experimental analysis of the lens‐forming competence of the cornea, iris, and retina in Xenopus laevis tadpoles
Authors: Bosco Luigi , Filoni Sergio , Paglioni Silvana
Published: June 2005

The present research was carried out using Xenopus laevis tadpoles at stage 50–51 to ascertain whether eye territories other than the outer cornea and the pericorneal epidermis have lens‐forming competence, particularly the iris and/or retina. Five experiments were performed: simple lentectomy; removal of lens, outer cornea, and pericorneal integument; removal of lens, outer cornea, and pericorneal integument, and simultaneous incision of retina; removal of lens, outer cornea and pericorneal integument, and simultaneous incision of dorsal iris; removal of lens and simultaneous lesion of iris and retina. Results show that when lentectomy is performed without damaging any territories other than the outer and inner cornea, lens regeneration is always from the outer cornea, and the iris and retina do not exhibit any lens‐forming competence. The iris and retina show no clear‐cut lens‐forming competence even after they have been stimulated by comparatively extensive lesions.
Aberrant spermiogenesis in X‐linked male‐sterile mutants of Drosophila melanogaster
Authors: Dybas Linda K. , Tyl Barbara T. , Geer Billy W.
Published: June 2005

Males expressing mutations of fertility genes situated in sections 19 and 20 of the X‐chromosome of D. melanogaster were examined to identify the genetic lesions. ms(1)16, located in 20B‐C, affected pre‐meiotic events and caused ultrastructural abnormalities of the axoneme and of the major mitochondrial derivative during spermiogenesis. ms(1)1, situated in 19F1–20A1–2 to 20A1–2–20B, influenced the stability of the axoneme. ms(1)14, located in 19E8–19F1 to 20A1–2, and ms(1)7, found in 19E6–8 to 19E8–19F1, did not effect detectable ultrastructural abnormalities in developing gametes. ms(1)4, located in 18F to 19C3–19E1, resulted in abnormal development of tbe paracrystalline body and elongation of the major mitochondrial derivative. The nature of the genetic defects makes it unlikely that these proximal genes act as components of a single regulatory unit.
Vision tuned to species bioluminescence emission in firefly Photinus pyralis
Authors: Lall Abner B.
Published: June 2005

The ERG spectral sensitivity of the dorsal sector of the compound eye in firefly Photinus pyralis possesses two maxima, one in the violet and the second in the yellow region of the spectrum, with a marked attenuation of sensitivity in the green resulting in a narrow yellow sensitivity identical in shape to the species bioluminescence emission spectrum. Since the spectral sensitivity curves of the lamina response obtained from eyes devoid of cornea and distal screening sleeve were similar to the ERG spectral sensitivity curves obtained form intact eyes, the distal screening pigment and the cornea cannot be implicated in causing the attenuation of sensitivity in the green.
Implanted cerebral ganglia produce supernumerary eyes and tentacles in host snails
Authors: Moffett Stacia , Austin Daniel R.
Published: June 2005

In the pulmonate snail Melampus bidentatus, cerebral ganglia from adult donors implanted into the hemocoel of adult host snails form connections with the host nervous system and periphery. In addition, approximately 50% of the implanted ganglia develop an eye on the surface of the ganglion, and approximately 25% of the host snails develop a supernumerary tentacle above the site where the implanted ganglion lies. The morphology of these sensory structures was examined by light and electron microscopy. Comparison of implant eyes with adult control eyes and regenerated eyes indicates that the same elements are present (cornea, lens, microvillar layer, pigment layer and cell layer), although implant eyes at four months and regenerated eyes at two months do not have pigment and microvillar layers as thick as the controls. The receptor cell structure is similar in all cases. The surface of the supernumerary tentacles is not as convoluted as that of control tentacles, but sensory cells and a neural link to the implant ganglion are present. An eye is often produced in the skin at the base of the supernumerary tentacle.
Drugs that block smooth muscle contraction inhibit in vivo ovulation in hamsters
Authors: Martin Gary G. , Talbot Prudence
Published: June 2005

We have demonstrated previously that smooth muscle cells (SMC) in the base of hamster follicles contract minutes before ovulation. The contraction of these cells correlates well in time with the development of a constriction in the base of the follicle. The purpose of this study was to determine whether contraction of SMC (1) produces this constriction and (2) is necessary for ovulation. We treated preovulatory hamster ovaries with six classes of drugs (lanthanides, calcium antagonists, local anesthetics, prostaglandins, cAMP modulators, and cytochalasin B) known to inhibit SMC contraction in other tissues. Drugs were injected into the experimental bursal cavity of a hamster 3 hours before ovulation; the contralateral ovary received no treatment and served as a control. Three hours after ovulation, the number of ruptured follicles on experimental and control ovaries were compared by light and electron microscopy. All the smooth muscle (SM) inhibitors, except those that affect cAMP levels and cytochalasin B, prevented (1) contraction of follicular SM, (2) constriction of the base of the follicle, and (3) ovulation. These results support the idea that contraction of follicular SMC constricts the follicle and is required for ovulation. The results further show that follicular SMC are activated by an influx of extracellular calcium and that prostaglandin F2α may be involved in promoting this contraction.
Ejection of algae in the green hydra symbiosis
Authors: McAuley P. J.
Published: June 2005

Green hydra appears to regulate strictly the symbiotic algae within its digestive cells. Numbers of algae in the Frome and Jubilee strains were not affected by either sulphate enrichment of the medium or starvation, although numbers of algae fell when photosynthesis was inhibited by darkness and /or DCMU, due to cessation of algal growth. Treatment with glycerol or the antibiotic trimethoprim caused ejection of algae; trimethoprim, but not glycerol, also inhibited algal growth. Glycerol and trimethoprim caused an increase in numbers of algae at the apical ends of digestive cells, and appearance of cohesive algal pellets in treated hydras' coelenterons and in the culture dish; in control hydra and those treated with darkness or DCMU, fewer algae were at the apexes of digestive cells, and no algal pellets were produced. It was concluded that ejection of algae is not the normal regulatory mechanism in the green hydra symbiosis, although the fact that certain treatments may cause algal ejection should be taken into account when algal proliferation is measured in green hydra.
Developmental expression of glucose and triose phosphate isomerase genes in teleost fishes (Brachydanio)
Authors: Pontier Paul J. , Hart Nathan H.
Published: June 2005

The ontogeny of glucosephosphate isomerase (GPI; E.C. 5.3.1.9) and triosephosphate isomerase (TPI; E.C. 5.3.1.1) isozymes in Brachydanio rerio, (zebra danio), B. albolineatus (pearl danio) and hybrids formed by their reciprocal crosses were examined by electrophoretic and spectrophotometric methods. The two species showed virtually identical adult, tissue‐specific distributions and developmental progressions for both GPI and TPI isozymes. The Gpi‐A and Tpi‐B loci were expressed in all tissues studied. The Gpi‐B locus was predominantly expressed in skeletal muscle and the Tpi‐A locus in eye, brain and ovary. The GPI‐A2, TPI‐A2, TPI‐AB and TPI‐B2 isozymes were continuously expressed from fertilization through 5 days postfertilization. The GPI‐B2 isozyme initially appeared at 35 hours postfertilization, temporally correlating with the early differentiation of trunk somite myoblasts. Spectrophotometric analysis of total GPI showed fluctuations in activity through 48 hours, followed by a steady increase through 4 days postfertilization. Total TPI showed increased activity by the end of gastrulation and a sharp rise in activity beginning at 25 hours postfertilization.

Embryos of reciprocal hybrids between B. rerio and B. albolineatus showed that isozymes derived from the activation of the paternal Tpi‐B, Gpi‐A and Tpi‐A alleles were initially detected at 20, 25, and 48 hours following fertilization, respectively. The maternal and paternal isozymes of the Gpi‐B locus were synchronously expressed at 35 hours postfertilization. The pattern of GPI‐B2 expression in hybrids followed a pattern similar to that in intraspecific crosses.

Exposure of B. rerio embryos to pulses of actinomycin D at various stages prior to 35 hours postfertilization showed that messenger RNA encoding the GPI‐B2 isozyme was first transcribed over a 14‐hour interval initiated during mid‐gastrulation. Translation of the GPI‐B2 message occurred during a 13‐hour period immediately preceding the embryonic expression of the GPI‐B2 isozyme. Our studies with Brachydanio indicate that several gene loci are activated at gastrulation and transcribe messenger RNA molecules coding for histospecific isozymes associated with later stages of organogenesis.
Magnetic field detection in sockeye salmon
Authors: Quinn Thomas P. , Merrill Ronald T. , Brannon Ernest L.
Published: June 2005

Previous research has indicated that lake‐migrating sockeye salmon fry have compass directional preferences, cued in part by magnetic fields. This paper reports the results of experiments designed to compare the magnetosensory system of salmon with those of other organisms. Unlike birds, the fry did not reverse their compass orientation 180° when the magnetic field's vertical component was inverted, but rather displayed northerly (31°) orientation similar to that of fry in two different control conditions (325° and 22°). These results agreed with the 349° bearing displayed in 1979.

Magnetized material (implicated as possible transducers in the magnetosensory systems of bacteria, honeybees, and homing pigeons) was not found (<2 × 10−7 e.m.u.) in 26 out of 30 fry examined. The material in the other 4 was probably environmental contamination, and not part of a sensory system. The mechanism of magnetic detection in salmon remains unknown, but consideration of the evolution and life history of the fish provides some clues as to the possible nature of the mechanism.
Inhibition of the hamster sperm acrosome reaction by transmethylation inhibitors
Authors: Meizel Stanley
Published: June 2005

Two inhibitors of somatic cell transmethylation, homocysteine thiolactone (Hcy) and 3–deazadenosine (3–DZA), inhibited the acrosome reactions of hamster sperm in vitro. Hcy (250 μM) or 3–DZA (200 μM) inhibited acrosome reactions by approximately 30% after 4 hours of incubation with washed sperm in a capacitating medium containing epinephrine, taurine, and bovine serum albumin. Inhibition by 3–DZA decreased by 5 hours, but inhibition by Hcy did not. Incubation of sperm with the combination of both inhibitors inhibited acrosome reactions by nearly 60% at 4 hours, and did not appreciably decrease with time up to 5 hours. These results are the first to demonstrate that such inhibitors can interfere with the acrosome reaction and taken together with the effects of Hcy and 3 – DZA on somatic cells, suggest that sperm protein and/or phospholipid transmethylation is/are involved in capacitation and/or the acrosome reaction.
Physalia venom mediates histamine release from mast cells
Authors: Cormier Susan M.
Published: June 2005

A proteinaceous venom isolated from Portuguese man‐of‐war (Physalia physalis) nematocysts causes degranulation and histamine release from mesenteric mast cells and isolated peritoneal mast cells.
Makisterone A: The molting hormone of larval Oncopeltus?
Authors: Kelly Thomas J. , Woods Charles W. , Redfern Robert E. , Bořkovec Alexej B.
Published: June 2005

The major ecdysteroids of last‐stage Oncopeltus fasciatus larvae were determined by HPLC/RIA analysis. An ecdysteroid other than ecdysone or 20‐hydroxyecdysone, probably makisterone A, was the major ecdysteroid in hemolymph and in whole body extracts of 4‐ to 5‐day‐old larvae, when hemolymph ecdysteroid titers were at their peak. Little, if any, ecdysone or 20‐hydroxyecdysone was detected in the hemolymph. Bioassay of the relative activities of ecdysone, 20‐hydroxyecdysone, and makisterone A in last‐stage larvae revealed that makisterone A was ten times more active than 20‐hydroxyecdysone, and that ecdysone was inactive at doses as high as 1 mg/ml, its limit of solubility in 10% ethanol. Thus, it is suggested that makisterone A is the molting hormone in Oncopeltus. The implications of this discovery are discussed.
Cuticle synthesis and inhibition of vitellogenesis: Makisterone A is more active than 20‐hydroxyecdysone in female milkweed bugs
Authors: Aldrich J. R. , Svoboda J. A. , Thompson M. J.
Published: June 2005

Makisterone A (24‐methyl‐20‐hydroxyecdysone) is approximately ten times more potent than 20‐hydroxyecdysone in the stimulation of cuticle synthesis and inhibition of vitellogenesis when injected into 3‐day‐old virgin females of Oncopeltus fasciatus. By day 6 postinjection with an active dose of makisterone A, the new cuticle appears identical in color pattern and morphology to the old adult cuticle, although the insects never undergo ecdysial contractions. Since milkweed bugs are also known to be incapable of dealkylating phytosterols, and makisterone A has been previously identified as the predominant ecdysteroid from embryonated eggs of this species, it is likely that makisterone A is the molting hormone of O. fasciatus or is closer to the structure of the indigenous hormone than is 20‐hydroxyecdysone.
Differentiation of the avian latissimus dorsi primordium: Analysis of fiber type expression using the myosin ATPase histochemical reaction
Authors: Butler Jane , Cosmos Ethel
Published: June 2005

Typically, fast twitch fibers of the adult avian posterior latissimus dorsi (PLD) muscle express alkali stable myosin ATPase histochemical activity, whereas slow tonic fibers of the anterior latissimus dorsi (ALD) muscle exhibit dual acid and alkali stability. Since PLD fibers cross‐reinnervated by the nerve of the ALD muscle also demonstrate dual stability, we sought to determine whether the ALD nerve induces this new phenotype de novo or de‐represses an embryonic phenotype repressed during further development in ovo. Chick embryos from Day 2 in ovo onward were frozen in toto, and the development of myosin ATPase histochemical profiles following alkali and acid preincubation was determined for myo‐genic cells destined to form the ALD and PLD muscles. In addition, the silver cholinesterase reaction was employed on serial sections to investigate early muscle‐nerve interaction in ovo. Our results indicate that all myogenic cells of the primary dorsal muscle mass, including those of the future ALD and PLD muscles, demonstrate their first myosin ATPase response at Stage (St) 25. At this time (4.5 days in ovo), only alkali stable enzymic activity is expressed. By St 28 (5.5 days) a distinct latissimus dorsi (LD) primordium has cleaved from the dorsal muscle mass and the entire primordium still exhibits only alkali stability. As development proceeds and the LD primordium separates into recognizable anterior and posterior regions (St 29, 6.0 days through St 30, 6.5 days), the future PLD muscle continues to express only alkali stability, whereas the future ALD muscle now demonstrates dual stability. By St 32 (7.5 days), these two muscles are completely separated, and during the remainder of in ovo development the profiles characteristic of adult slow tonic versus fast twitch fibers remain unaltered. Thus, our results indicate that, during cross‐reinnervation ex ovo, the ALD nerve induces the expression of a new phenotype never exhibited by potential fast twitch PLD fibers during the entire embryonic period, including their incipient formation. Moreover, our results indicate that the histochemical reaction for myosin ATPase activity provides an excellent enzymic marker both for the identification of myogenic cells and individual muscle primordia, and, for the detection of muscle fiber type differentiation during the first week of development in ovo.
Regional changes in the binding of [3H] concanavalin A to mouse blastocysts at implantation: An autoradiographic study
Authors: Carollo J. R. , Weitlauf H. M.
Published: June 2005

Implanting and delayed‐implanting mouse blastocysts were incubated in vitro with [3H] concanavalin A (Con A), and the distribution of binding on their surfaces was determined by light microscopic autoradiography. The density of binding was uniform on the trophectoderm of delayed‐implanting embryos and was not changed on the polar surface of implanting embryos. However, binding was reduced on the proximal mural and distal mural trophectoderm of implanting blastocysts by 36% and 60%, respectively. These results suggest that there is a regional reduction in the density of mannose‐like sugars on the surface of mouse blastocysts at the time of attachment and implantation.
Resumption of DNA synthesis during activation of delayed implanting mouse blastocysts
Authors: Given Randall L. , Weitlauf Harry M.
Published: June 2005

Cell division ceases in mouse blastocysts during the extended dormant period associated with delayed implantation but resumes following activation of the embryos by administration of 17β‐estradiol to the mother. To determine the temporal and spatial aspects of the resumption of DNA synthesis during activation, blastocysts were recovered from delayed implanting females at various intervals after an injection of 17β‐estradiol, incubated with 3H‐thymidine in vitro, and prepared for light microscopic autoradiography.

Although less than 4% of the cells were labeled in delayed implanting embryos, the proportion of labeled cells increased soon after the administration of 17β‐estradiol and reached a maximum of over 50% by 24 hours. This increase in labeling was not uniform in all regions of the embryo, i.e., the labeling index of the inner cell mass began a steady increase immediately after the injection of 17β‐estradiol while labeling of the polar and proximal mural trophoblast remained depressed for 6 and 12 hours, respectively, and only then began to increase. No labeling was present over the distal mural trophoblast in delayed implanting or activated blastocysts although cytological changes characteristic of primary giant cell transformation were present in activated embryos. These results indicate that the resumption of DNA synthesis is part of the overall increase in metabolic activity associated with activation. Furthermore, the sequential pattern of resumption of synthesis suggests that the ICM may influence the initiation of DNA synthesis in the surrounding trophoblast.
Scanning electron microscopic observations on sperm penetration in teleostean fish
Authors: Iwamatsu T. , Ohta T.
Published: June 2005

The process by which a spermatozoon penetrates through the micropyle apparatus into the egg cytoplasm in the teleost, Oryzias latipes, was examined with scanning electron microscopy. In the unfertilized egg, the egg surface beneath the inner opening of the micropylar canal did not differ distinctly from the rest of the animal pole area. A spermatozoon attached effectively to the egg 1–3 seconds after insemination. In the initial step of penetration, the spermatozoon still within the micropylar canal attached perpendicularly at its apical tip to the egg surface, then the sperm head was rapidly engulfed by the folded egg surface with its many microvilli. A large blister‐like fertilization cone with a microvillus‐free surface appeared on the egg surface surrounding the penetrating spermatozoon. Concomitantly, breakdown of the cortical alveoli was initiated in the animal pole. The spermatozoon disappeared from the outer surface of the egg before the fertilization cone completely retracted.

On the basis of these observations with Oryzias eggs, two steps in the sperm penetration process could be recognized: The first step was a rapid engulfment by the folded egg surface and the second was a slow engulfment by fertilization cone synchronized approximately with the initiation of the cortical reaction. The mechanism of block to polyspermy in teleostean eggs was discussed.
Comparison of hemoglobins from the genus Xenopus (amphibia salienta)
Authors: Muir A. V.
Published: June 2005

A survey of the electrophoretic mobility of hemoglobins of 14 species and subspecies of the genus Xenopus was undertaken. It was found that the variation between the different taxons considered was quite important in the number and the degree of the hemoglobin bands on polyacrylamide slab gels. The profiles of the hemoglobin electrophoretic pattern in tube gels gave corresponding results, confirming the variation between the different Xenopus species. The degree of resolution obtained on polyacrylamide slab gels was insufficient to allow one to distinguish between the subspecies of Xenopus laevis. Specific staining of the gels showed that the protein bands were in fact hemoglobins.

From the results obtained it appears that there are relative differences in the number and mobility of hemoglobin bands between the different species, these differences being important enough to stimulate interest in further investigation in this field, but, as far as this preliminary investigation indicates, not clear‐cut enough to use as a method of identification for isolated unknown species.
Development of the adult pelage in normal and hormone‐injected spiny mice (Acomys cahirinus)
Authors: Martin‐Dennis G. , Peitz B.
Published: June 2005

The dorsal pelage of the adult Egyptian spiny mouse (Acomys cahirinus) consists primarily of coarse brittle spines which differ from those of the juvenile pelage. The development of the adult pelage in juvenile spiny mice was examined in normal and estradiol‐or testosterone‐injected animals. Females complete the development of their adult pelage significantly faster than males. Both estradiol and testosterone injections speed pelage development in males. Testosterone causes a significant delay in the completion of the female's pelage. Studies of replacement of adult spines show that spine replacement is mosaic and slower than in other murid rodents.
The effect of pinealectomy, continuous light, and continuous darkness on metamorphosis of anadromous sea lampreys, Petromyzon marinus L.
Authors: Cole W. C. , Youson J. H.
Published: June 2005

The role of the pineal complex in lamprey metamorphosis was investigated by examining the influence of pinealectomy and continuous light and darkness on the initiation of this event in anadromous sea lampreys, Petromyzon marinus L. Larval lampreys, which on the basis of a condition factor were considered likely to enter metamorphosis in July, were separated in May of 1979 and 1980 into the following groups: (1) intact controls, (2) sham‐operated controls, (3) pinealectomized individuals, (4) those exposed to continuous light, and (5) those exposed to continuous dark. A statistical analysis of the numbers of animals that entered metamorphosis in each group indicated that the pineal complex is essential for the initiation of metamorphosis but that this process is not influenced by continuous light or dark. The importance of the pineal complex to metamorphosis was supported by morphological evidence that, in all presumably pinealectomized individuals that entered metamorphosis, the complex had apparently not been removed during the surgical procedure. The ways in which the pineal complex may be involved in lamprey metamorphosis are discussed.
Sexual dimorphism of SDS peptide patterns from the submaxillary glands of mice
Authors: Kim Yong Kyu , Ogita Zen‐Ichi
Published: June 2005

In mice (Mus musculus) sexual dimorphism is evident in the structure and function of the submaxillary glands, convoluted tubules being much more prominent in males than in females. Several enzymes are more abundant in the male gland. We have examined the submaxillary glands of male and female mice for the amounts of arginine peptidase and have made electrophoretic scans of SDS peptides in extracts of male and female glands during postnatal development and after androgen treatment. Larger peptides are relatively more abundant in female extracts, and smaller peptides are more abundant in the male extracts. The peptide patterns reflect the amount of arginine peptidase present in the extracts. No arginine peptidase could be detected in submaxillary salivary glands of mice from birth until 3 weeks of age. Then enzyme activity gradually increased, apparently induced by androgen hormones. The amounts of SDS peptides of high molecular weight steadily decreased with increasing age of the mouse and with increasing titers of arginine peptidase. Castration of the male led to the appearance of female SDS patterns; male patterns reappeared after treatment with testosterone. Females could be induced to form male patterns of SDS peptides by treatment with androgen hormones.
The level of N‐acetylserotonin and melatonin in the brain of male rats: Diurnal variations and effects of pinealectomy
Authors: Pang S. F. , Tang P. L. , Yu H. S. , Yip M. K.
Published: June 2005

The levels of N‐acetylserotonin and melatonin (n‐acetyl‐5‐methoxytryptamine) in the rat brain were studied. Male rats were housed under a photoperiod of 12L:12D. After 2 weeks, the rats were sacrificed in light or in dark at 4‐hour intervals round the clock. Brain melatonin and N‐acetylserotonin were extracted by chloroform at ⩾ pH 10 and ethyl acetate at ⩽ pH 3 respectively and quantified by radioimmunoassay. There was a circadian rhythm of brain melatonin (F < 0.05) with a nadir at 1600 h and a zenith at 0400 h. Brain N‐acetyl‐serotonin, unlike brain melatonin, demonstrated no diurnal variation. Effects of pinealectomy on brain N‐acetylserotonin and melatonin were also studied. Male rats were housed as noted. After 2 weeks, they were pinealectomized or shamoperated. The animals were killed in light or in dark 1 week after operation. The levels of brain melatonin at 2400 h and 0400 h were significantly lowered (P < 0.5) following pineal removal. Pinealectomy, however, has no observable effect on the level of brain N‐acetylserotonin. Our findings suggest that (1) there is a diurnal rhythm of brain melatonin, (2) the elevation of brain melatonin in the dark period is dependent on the pineal, (3) brain N‐acetylserotonin has no diurnal variation, and (4) brain N‐acetylserotonin is not affected by pinealectomy.