bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of enzymes that degrade crab exoskeleton: II. Two acid proteinase activities
Authors: O'Brien Jack J. , Skinner Dorothy M.
Published: June 2005

Specific proteins extracted from the membranous layer of the exoskeleton of the Bermuda land crab, Gecarcinus lateralis, are degraded at acid pH values by two proteinase activities (AP I and AP II) extracted from integumentary tissues. The pH optimum of AP I was about 5; it does not bind to cation exchange resin and was strongly inhibited by pepstatin A. The pH optimum of AP II was about 4; it binds to a cation exchange resin and was inhibited by cysteine proteinase inhibitors. AP II shared some characteristics with the human lysosomal proteinase cathepsin B. Unlike cathepsin B, which binds to the cysteine proteinase inhibitor E‐64 in a 1:1 ratio, AP II was not completely inhibited by E‐64, and only at the lower concentrations of inhibitor was there a linear relationship between enzyme activity and amount of inhibitor.
Skull development during anuran metamorphosis: III. Role of thyroid hormone in chondrogenesis
Authors: Hanken James , Summers Cliff H.
Published: June 2005

Metamorphosis of cranial cartilages in anuran amphibians constitutes one of the most dramatic and extensive ontogenetic transformations in vertebrates. We quantitatively examined the role of thyroid hormone (3,3′,5‐triiodo‐L‐thyronine; T3) in mediating gross aspects of this morphological repatterning in the skull of the Oriental fire‐bellied toad, Bombina orientalis. T3 was administered via plastic (Elvax) micropellets in three treatment dosages (2.5, 0.25, and 0.025 μg) and one control dosage (0 μg) to tadpoles of three Gosner developmental stages–28/29, 30/31, and 32/33; tadpoles were recoved up to 8 d (treatment and control dosages) or 14 d (control dosage) later. Response of larval cartilages to exogenous T3 was dosage dependent but not implant‐stage dependent; chondrogenic tissues that participate in metamorphic transformation are competent to respond to T3 well before they normally do. Metamorphic effects of T3 were visible within 2 d; in most treatment groups, the normal metamorphic sequence was two‐thirds complete after 8 d. While T3 also induced precocious ossification, the normal temporal relation between bone formation and cartilage transformation was dissociated in experimental groups. Morphological integration between cartilage and bone during cranial metamorphosis is at least partly the result of each tissue responding independently to endocrine factors.
Locomotion of sponges and its physical mechanism
Authors: Bond Calhoun , Harris Albert K.
Published: June 2005

Active locomotion by individual marine and freshwater sponges across glass, plastic and rubber substrata has been studied in relation to the behavior of the sponges' component cells. Sequential tracing of sponge outlines on aquarium walls shows that sponges can crawl up to 160 μm/hr (4 mm/day). Time‐lapse cinemicrography and scanning electron microscopy reveal that moving sponges possess distinctive leading edges composed of motile cells. Sponge locomotion was found to be mechanically similar to the spreading of cell sheets in tissue culture both with respect to exertion of traction (which causes the wrinkling of rubber substrata) and with respect to the patterns of adhesive contacts formed with the substratum (as observed by interference reflection microscopy). Other similarities include the orientation of sponge locomotion along grooves and the preferential extension onto more adhesive substrata. Neither the patterns of wrinkling produced in rubber substrata nor the distributions of adhesive contacts seen by interference reflection microscopy show evidence of periodic, propagating waves of surface contractions, such as would be expected if the sponges' mechanism of locomotion were by peristalsis or locomotory waves. Our observations suggest that the displacement of sponges is achieved by the cumulative crawling locomotion of the cells that compose the sponge's lower surface. This mode of organismal locomotion suggests new explanations for the plasticity of sponge morphology, seems not to have been reported from other metazoans, and has significant ecological implications.
Sex pheromone in a marine polychaete: Determination of the chemical structure
Authors: Zeeck Erich , Hardege Jörg , Bartels‐Hardege Helga , Wesselmann Günter
Published: June 2005

A sex pheromone of the marine polychaetePlatynereis dumeriliiis chemically characterized as 5‐methyl‐3‐heptanone. There exist two optical isomers, the S(+)‐isomer produced by males and acting on females, the R(−)‐isomer produced by females and acting on males. The basic structure shows a close relationship to insect pheromones and is of interest with regard to the evolution of pheromones.
Direct observation of cold‐shock effects in ram spermatozoa with the use of a programmable cryomicroscope
Authors: Holt W. V. , Morris G. J. , Coulson G. , North R. D.
Published: June 2005

Cryoinjury in individual ram spermatozoa was investigated in cells cooled at 10°C/min on a programmable Cryomicroscope. In physiological buffer and cryoprotective media, there was a smooth decline in sperm swimming speed with decreasing temperature; cooling in buffer caused a marked decline in the proportion of cells displaying forward progression, especially once the temperature fell below 16°C. Spermatozoa cooled in the presence of rhodamine 123, a mitochondrial‐specific dye, showed that abolition of sperm motility by cold shock in buffer was not due to mitochondrial inactivation. Temperature decline through the region of 10°C caused a number of spermatozoa in buffer to undergo a sudden asymmetric bending of the flagellum in the region of the midpiece. Ultrastructural studies suggest that this was caused by an unstable, asymmetric membrane lesion. Spermatozoa cooled in the presence of cryoprotective media showed better recovery of motility after rewarming and failed to exhibit the bending effect described above.
Serum high‐density lipoprotein in the crab, Cancer antennarius Stimpson: II. Annual cycles
Authors: Spaziani Eugene
Published: June 2005

Hemolymph lipoproteins in crustaceans are of the high‐density type (HDL). Serum concentrations of HDL were measured monthly during 1982–1987 in crabs (Cancer antennarius) collected off the coast of Southern California. The annual profiles of concentrations feature female‐specific elevations during October–December, with the peak in November being an average four‐fold higher than the lows of early summer. The single departure from this pattern occurred in February–March, 1983, coinciding with a rise in water temperature due to the El Nino phenomenon. Females collected in most months were in various stages of egg maturation and brooding females also could be found at any time of year. Despite this heterogeneity, evidence supports an hypothesis that the annual increase in serum HDL occurs when most females in the population are actively vitellogenic.
Differential expression of the C4 isozyme of lactate dehydrogenase (LDHC4) in developing bonefish (Albula sp.)
Authors: Pfeiler Edward , Vrijenhoek Robert C.
Published: June 2005

Starch‐gel electrophoresis revealed that the C4 isozyme of lactate dehydrogenase (LDHC4) predominated in the gelatinous, postcranial body mass of metamorphosing leptocephalous larvae of the bonefish (Albula sp.), a primitive teleost fish. At the end of metamorphosis, when the juvenile stage was reached and the gelatinous matrix had been resorbed and replaced by muscle and bone, the relative activity of the C4 isozyme was reduced, and the expression of the A4 and B4isozymes increased. The A4 isozyme then became the dominant form in white muscle of developing juveniles. The C4 isozyme was also expressed in juvenile eye, liver, heart, brain, gut, gill, and red muscle, but the B4 isozyme showed the highest relative activity in these tissues. These results suggest (1) that the Ldh‐C gene is the most active of the three LDH genes in the leptocephalus, (2) that the C4 isozyme of LDH performs a critical and specific function in larval metabolism, and (3) that metamorphosis is accompanied by tissue‐specific increases in activity of the Ldh‐A and Ldh‐B genes.
Evidence that regenerative ability is an intrinsic property of limb cells in Xenopus
Authors: Sessions Stanley K. , Bryant Susan V.
Published: June 2005

Xenopus laevis, exhibits an ontogenetic decline in the ability to regenerate its limbs: Young tadpoles can completely regenerate an amputated limb, whereas post metamorphic froglets regenerate at most a cartilagenous “spike.” We have tested the regenerative competence of normally regenerating limb buds of stage 52–53 Xenopus, tadpoles grafted onto limb stumps of postmetamorphic froglets. The limb buds become vascularized and innervated by the host and, when amputated, regenerate limbs with normal or slightly less than normal numbers of tadpole hindlimb digits. Reciprocal grafts of froglet forelimb blastemas onto tadpole hindlimb stumps resulted in either autonomous development of tadpole hindlimb structures and/or formation of a cartilaginous spike typical of froglet forelimb regeneration. Our results suggest that the Xenopus, froglet host environment is completely permissive for regeneration and that the ability to regenerate a complete limb pattern is an intrinsic property of young tadpole limb cells, a property that is lost during ontogenesis.
Triiodothyronine increases translatable albumin messenger RNA in Rana catesbeiana tadpole liver
Authors: Schultz James J. , Price Margaret P. , Frieden Earl
Published: June 2005

The effects of both 3,5,3′‐triiodo‐L‐thyronine and spontaneous metamorphosis on Rana catesbeiana, liver mRNA were studied using in vitro translation of isolated liver poly(A)+ RNA in a rabbit reticulocyte lysate system. Conventional phenol extraction methods yielded degraded RNA due to high levels of endogenous ribonucleases released upon homogenization of Rana catesbeiana, liver. Isolation of intact total RNA was achieved using the potent ribonuclease denaturant, guanidinium thiocyanate. Adult bullfrog serum albumin was purified to homogeneity and a monospecific antibody was elicited against it. A serum protein of 23,000 daltons that migrated near serum albumin on a 6% native gel was also purified to homogeneity. A monospecific antibody was also raised against this protein. Both antibodies were used to quantitatively immunoprecipitate the in vitro translation products of poly(A)+ RNA isolated at intervals following a single injection of triiodothyronine or during various stages of spontaneous amphibian metamorphosis. Triiodothyronine caused a sevenfold increase in translatable albumin mRNA and a threefold increase in translatable mRNA for the 23,000 dalton protein. These increases are consistent with a nuclear initiated mechanism for thyroid hormone action during amphibian metamorphosis.
Effect of a light pulse during the dark on photoperiodic regulation of the rate of thyroxine‐induced, spontaneous, and prolactin‐inhibited metamorphosis in Rana pipiens tadpoles
Authors: Wright Mary L. , Jorey Suzanne T. , Blanchard Linda S. , Basso Carolyn A.
Published: June 2005

Since Rana pipiens tadpoles injected with thyroxine (T4) early in the dark develop more slowly than those injected in the light, we studied the effect of giving a light pulse of 1 hr early in the dark. Tadpoles injected under a 7.5‐W red light bulb in a darkened room with 0.2 μg T4 daily at 2200 hr went through metamorphosis faster on a 12L:3D:1L:8D cycle with a light pulse after injection than on a 12L:12D cycle without a light pulse, and even faster on a 12L:1.5D:1L:9.5D cycle with a light pulse before the injection. Thus a 1‐hr light pulse counteracted the metamorphic delay resulting from administration of T4 in the dark, and set in motion the conditions that resulted in a more rapid response to an injection of T4. However, a 1‐hr light pulse in the early dark had no effect on growth and development of older or younger untreated tadpoles or those constantly immersed in 30 μg/liter T4.

Larvae on 21L:3D with T4 injection in the dark and on 12L:3D:1L:8D with T4 injection at 0700 hr just before the start of the main light phase progressed faster than 12L:3D:1L:8D with injection at 2200 hr in the dark before only a 1‐hr light pulse. Thus the length of the light phase immediately after T4 injection was significant. There was no difference on 12L:12D and 12L:3D:1L:8D cycles in the effectiveness of daily injections of 10 μg prolactin (PRL) in the early dark at 2200 hr in promoting tail growth or antagonizing tail resorption induced by T4 immersion. Under these conditions, PRL utilization did not appear to be inhibited by the light pulse.
Strain differences in early mouse embryo development in vitro: Role of the nucleus
Authors: Robl J. M. , Lohse‐Heideman J. K. , First N. L.
Published: June 2005

Mouse embryos of many strains are blocked in development at the two‐cell stage when placed in culture at the one‐cell stage. If, however, they are placed in culture at the two‐cell stage, they develop to blastocysts at a high rate. We investigated the transcriptional and translational systems in blocked embryos by assaying enzymatic activity of the protein product of an injected gene and found these systems to be functioning normally. The role of the nucleus was investigated by reciprocal nuclear transplants between blocked and nonblocked embryos. The results indicate that the source of the nucleus was of equal importance to that of the cytoplasm for the successful development of embryos cultured from the one‐cell stage. When cultured from the two‐cell stage, however, the nucleus was solely responsible for strain differences in culture rates.
S6 phosphorylation is regulated at multiple levels in Xenopus laevis oocytes
Authors: Wasserman William J. , Freedman Alan , Penna Mary Jo
Published: June 2005

It is known that the 40s ribosomal protein S6 undergoes a dramatic increase in its level of phosphorylation during Xenopus oocyte meiotic maturation in response to progesterone stimulation. During prophase arrest, the majority of S6 has 0 moles phosphate per mole protein; this increases to 4–5 moles phosphate per mole protein by the time of germinal vesicle breakdown (GVBD). Our in vitro and in vivo studies indicate that the accumulation of phosphate on S6 is the net result of a 4–5‐fold increase in S6 kinase activity and a 30–50% decrease in the rate of dephosphorylation and/or turnover of phosphate groups on S6 in maturing oocytes. In addition, the level of phosphorylation of S6 on 80s monosomes injected into non‐hormone‐stimulated oocytes was unexpectedly high. This indicates that the S6 kinase/phosphatase ratio in prophase arrested oocytes is higher than anticipated from previous studies. This observation implies that the majority of the oocyte ribosomes may be sequestered from any S6 kinase during meiotic prophase. Furthermore, these observations suggest that a portion of the increased accumulation of phosphate on S6 may be the result of increased accessibility of the ribosomes to S6 kinase during oocyte meiotic maturation.
Renal structural flexibility in response to environmental water stress in feral hogs
Authors: Zervanos Stam. M. , Naveh Sharon
Published: June 2005

Several morphological characteristics of the kidney were studied to determine the degree of acclimatization that may occur in three groups of feral hogs raised under different environmental conditions. Two groups of hogs were living in the wild, while another was raised in captivity for three generations and was directly descended from one of the wild‐living groups. The two groups of wild hogs were living under two different types of water stress conditions. One group experienced periodic drought, and the other ate a high salt diet. The captive hogs were given food and water ad libitum. The captive‐raised hogs had significantly lower relative medullary thickness (RMT) and relative medullary area (RMA) values (RMT of 2.35; RMA of 0.35) than either group of hogs living in the wild (RMT of 2.70 and 2.69; RMA of 0.41 and 0.44). Since the feral hogs living in the wild were exposed to a higher degree of water stress than the captive‐raised hogs, it was concluded that the differences in observed kidney structure were due to acclimatization.
Multiple functions of carbonic anhydrase in the crustacean gill
Authors: Henry Raymond P.
Published: June 2005

The enzyme‐catalysed hydration of CO2 gas by carbonic anhydrase produces the ionic species H+ and HCO3−. The chemical species involved in the reaction scheme are further used in a variety of different physiological and biochemical processes, each of which at least potentially relies on carbonic anhydrase to keep those chemical species from being limiting. Two such processes, CO2 excretion and ion uptake, occur in the crustacean gill. On the surface it would appear that these processes are mutually exclusive in a single organ, as the former requires the net dehydration of HCO3−, and the latter requires the net hydration of CO2. That carbonic anhydrase can meet the requirements of both processes is due to its compartmentalization within different subcellular fractions of the gill tissue. Carbonic anhydrase associated with the basal‐lateral branchial membrane mobilizes hemolymph HCO3− to CO2 for excretion, while intracellular (cytoplasmic) carbonic anhydrase, through the catalysed hydration of CO2, provides H+ and HCO3− for use in Na+ and Cl− uptake.
Determinants of the larval molting pattern of the crustacean Balanus eburneus Gould (Cirripedia: Thoracica)
Authors: West Terry L. , Costlow John D.
Published: June 2005

Larval development of the thoracican cirripede Balanus eburneus is invariant, consisting of six naupliar instars and a terminal nonfeeding cypris instar. In order to elucidate determinants of its fixed instar molting pattern we tested the following hypotheses: (1) the rate of morphogenesis is correlated with the rate of molting; (2) the timing of the morphogenetic molt to the cyprid is time (age) dependent; and (3) initiation of the molt to the cyprid is dependent upon the accumulation of a minimum amount of energy reserves. Naupliar food supply was manipulated in order to vary rates of molting and accumulation of energy reserves. Total oil cell volume per larva was used to nondestructively estimate energy reserve level.

Compound eye development and thoracic appendage development during the six naupliar instar were confined to specific phases of the molt cycle. Suspension of the molt cycle resulted in suspension of morphological development. Initiation of the molt to the cyprid was neither time dependent nor a function of larval oil cell volume. However, the rate of passage through the molt cycle increased abruptly in larvae having an oil cell volume greater than 4–6 × 104 μm3. Nauplii entering the final phase of the molt cycle (D2–4) would attempt to complete development to the cyprid irrespective of their oil cell volume. Correlations between cypris oil cell volume and cypris metamorphic success implied that the naupliar oil cell volume “threshold” of 4–6 × 104 μ3 represented the amount of energy reserves needed to complete covert developmental events rendering the cyprid capable of successfully metamorphosing to the juvenile.

These results suggest that molt cycle stage‐specific morphogenesis and growth (energy reserve accumulation) are important determinants of the fixed instar molting of B. eburneus larvae. Comparisons with studies of larval crustaceans which vary instar number indicate (1) greater independence between the processes of molting and morphogenesis among species with a variable instar molting pattern and also that (2) growth is an important determinant of each type of molting pattern.
Influence of thyroidal status on ovarian function in rainbow trout, Salmo gairdneri
Authors: Cyr Daniel G. , Eales J. G.
Published: June 2005

Female rainbow trout were rendered either hypothyroid by ipodate injection or hyperthyroid by immersion in a 3,5,3′‐triiodo‐L‐thyronine (T3) solution or by feeding T3‐supplemented pellets, and ovarian function was evaluated from the gonadosomatic index (gonad weight .102. body weight−1 = GSI), plasma 17β‐estradiol (E2) level, or the ability in vitro of ovarian pieces to release E2 in the presence of salmon gonadotropin (sGtH). Hypothyroidism for 7 or 22 days depressed GSI or in vitro ovarian E2 release. Modest hyperthyroidism for 7 or 22 days, which raised plasma T3 from 1.6–3.3 ng/ml (controls) to 4.1–7.7 ng/ml, significantly increased GSI and in vitro ovarian E2 release. However, at higher T3 levels (21–33 ng/ml) there was no increase in GSI and either no increase or a significant decrease in ovarian E2 release. None of these treatments altered the plasma E2 levels although T3 treatment significantly enhanced the effect of injected sGtH in elevating E2 level. It is concluded that T3 at physiologic levels enhances ovarian growth and GtH stimulation of E2 production, but when plasma T3 levels exceed those required to saturate putative T3 receptor sites, T3 tends to inhibit ovarian function.
Secretion of ecdysteroid by sheaths of testes of the gypsy moth, Lymantria dispar, and its regulation by testis ecdysiotropin
Authors: Loeb M. J. , Brandt E. P. , Woods C. W. , Bell R. A.
Published: June 2005

Testes of the gypsy moth, Lymantria dispar, secrete ecdysteroid in vitro during the silk‐spinning pharate pupa stage and in mid to late adult development during the pupal stage. Low titers (3–6 pg/μl) of exogenous 20‐hydroxyecdysone are required to elicit endogenous ecdysteroid production. Testis ecdysiotropin (TE) was detected in acid methanolic extracts of brains of immobile pharate pupae and mid‐development pupae. It was possible to activate early last‐instar testes of both L. dispar and Heliothis virescens to synthesize ecdysteroid by exposing them to TE prepared from pupae of either species. Although testes of L. dispar contained no detectable ecdysone, they were able to convert (3H) ecdysone to 20‐hydroxyecdysone and a highly polar fraction. The active ecdysteroid product of L. dispar testes is probably 20‐hydroxyecdysone.
Maternal triiodothyronine injections cause increases in swimbladder inflation and survival rates in larval striped bass, Morone saxatilis
Authors: Brown Christopher L. , Doroshov Serge I. , Nunez Jose M. , Hadley Carl , Vaneenennaam Joel , Nishioka Richard S. , Bern Howard A.
Published: June 2005

We have experimentally elevated the triiodothyronine (T3) content of striped bass (Morone saxatilis) eggs by injecting female striped bass intramuscularly with a large dose of T3 (20 μg/g body weight) shortly before the induction of spawning. The significant elevation of T3 concentrations in the eggs from the hormone‐injected fish (to 180 ng per gram), compared with those of vehicle injected controls (about 19 ng/g), confirms the transfer of T3 from the maternal circulation into oocytes. There were significant differences in the development of embryos and larvae from the two groups. Within the first week after hatching, the hormone‐treated cohorts showed significantly greater larval body area, length, and dry weight, despite similar patterns of yolk and oil‐globule utilization. The rate of swimbladder inflation and the survival rate were also significantly enhanced in the cohorts produced by T3‐treated females. There was a positive and highly significant correlation between the concentration of T3 in the unfertilized oocytes and the rate of survival within the cohort. The improvement in larval survival may be a result of the maintenance of elevated T3 levels through the first week of development: during the transition to active feeding but before the onset of larval thyroid function. Thyroid hormone supplements appear to confer a distinct advantage to larval striped bass during this early, fragile developmental stage.
Role of mitotic asters in accumulation of pigment granules around nuclei in early amphibian embryos
Authors: Kobayakawa Yoshitaka
Published: June 2005

Pigment granules accumulate around nuclei during the cleavage stage in amphibian embryos (Kobayakawa, J. Embryol. Exp. Morphol., 88:293–302, 1985). In Rana rugosa embryos, this unidirectional intracellular transport of pigment granules was found to occur mainly at each mitotic stage of 4th to 6th cell cycles in vegetal blastomeres. Immunocytochemical staining confirmed the growth of astral rays that fully develop at anaphase and telophase in each mitotic stage and also suggested an association of pigment granules with the microtubules. Microtubule inhibitors suppressed the accumulation of pigment granules, which appears to depend, around nuclei, on microtubular structures, probably astral rays in mitosis.
A prolonged cartilaginous phase in newt forelimb skeletal regeneration
Authors: Libbin Richard M. , Singh Inder J. , Hirschman Albert , Mitchell Ormond G.
Published: June 2005

The morphologic events leading to the regrowth of the amphibian limb have long been known, yet it is poorly appreciated that even when the limb appears outwardly restored, its skeletal parts may be formed entirely of cartilage. To determine when forelimb skeletal ossification begins and is completed in the spotted newt Notophthalmus viridescens, limbs from animals that had sustained midhumeral amputations were examined at intervals of up to 270 days. At this time, most regenerated skeletal parts were undergoing ossification, but those of the wrist remained entirely cartilaginous. Calcium content of regenerated bones was deficient, and X‐ray diffraction analysis disclosed the presence of apatite crystals with minimally discernible orientation.
Effect of dopamine, cyclic AMP, and pericardial organs on sodium uptake and Na/K‐ATPase activity in gills of the green crab Carcinus maenas (L)
Authors: Sommer Michael J. , Mantel Linda H.
Published: June 2005

Injection of 10−5 M dopamine or 10−6 M dibutyryl cyclic AMP (dbcAMP) into intact Carcinus maenas significantly increased influx of sodium from 100% sea water. Injection of pericardial organ (PO) extract, which contains dopamine, also increased influx of sodium. Animals injected with dopamine or PO extract and gills treated with dbcAMP in vitro showed increased Na/K‐ATPase activity in the microsomal fraction of the gills. These results suggest a mechanism for short‐term activation of Na/K‐ATPase when crabs are transferred to a dilute medium.
Effect of polyamines and palmitoyl‐coenzyme A on glucose‐6‐phosphate dehydrogenase from the hepatopancreas of the sea mussel Mytilus edulis L
Authors: Rodriguez‐Torres A. M. , Villamarin A. , Ramos‐Martinez J. I.
Published: June 2005

Aliphatic polyamines are able to relieve the inhibition of glucose‐6‐phosphate dehydrogenase (G6PDH) by palmitoyl‐coenzyme A (CoA). Of the polyamines assayed, spermine was the most effective in relieving this inhibition, followed by spermidine and ethylenediamine. These data suggest that the extent of the ability to relieve the inhibition depends on the number of amino groups in the polyamine.

The polyamines act specifically on palmitoyl‐CoA to free G6PDH from the inhibition by acyl‐CoA. Polyamines also decrease the inhibition of G6PDH by NADPH. The combination of these two effects results in an observed increase in G6PDH activity.
Critical period for determining claw asymmetry in developing lobsters
Authors: Govind C. K. , Pearce Joanne
Published: June 2005

The pair of enlarged chelipeds or claws in the lobster Homarus americanus is differentiated into a major crusher claw with a closer muscle of slow fibers only and a minor cutter claw with a closer muscle of predominatly fast fibers. Claw placement is random and can be controlled by removing one claw in the juvenile 4th or 5th stage. This induces the contralateral intact claw to become a cruscher, while the regenerated claw develops into a cutter (Emmel, '08). Rearing lobsters with a substrate (oyster chips) promotes the development of class asymmetry, whereas a substrate‐free environment (smooth surface) promotes the development of paired cutter claws (Lang et al., '78). Consequently, by rearing lobsters with or without a substrate at selected periods of juvenile development, we have delimited the critical period for claw determination to the 5th stage. During this 2‐week period, the presence of a substrate for a period of at least five days is necessary for the development of claw asymmetry.
Evidence for regulation following amputation and tissue grafting in the developing mouse limb
Authors: Wanek Nancy , Muneoka Ken , Bryant Susan V.
Published: June 2005

Procedures are now available to experimentally manipulate postimplantation mouse embryos in situ and allow development to continue into postnatal life (Muneoka, K., N. Wanek, and S.V. Bryant (1986) J. Exp. Zool., 239: 289–293). We have investigated the ability of the well formed hindlimb bud to regulate following two experimental operations: amputation and wedge grafts designed to confront anterior and posterior cells. After comparing the resultant limbs with the fate maps of the relevant states, we conclude that the developing hindlimb bud at stage 7/8 (equivalent to stage 27/28 of the chick) is capable of partial regeneration of the peripheral digits following amputation and capable of supernumerary digit tip formation after grafting of a wedge of anterior tissue to a posterior position.
Failure of fertilization following abbreviated copulation in the ferret (Mustela putorius furo)
Authors: Miller Brian J. , Anderson Stanley H.
Published: June 2005

In the first experiment, copulations in 10 domestic ferrets were interrupted 5 minutes after penetration. Ten control females were bred without interruption to the same males. Both control and experimental animals were rebred in the same manner to the same males 24 hours later. Sperm were present in all postcoital washes. We allowed all females from the first experiment to proceed to their expected data of parturition. All females who had been Interrupted during copulation failed to conceive, whereas all controls produced litters. In a second experiment, the same procedure was followed; however, in this experiment, ferret oviducts and uteri were flushed 10 days after copulation. Nine control females (one failed to ovulate) averaged 5.2 blastocysts (range 2–10; S.D. = 5.8) per animal. Of nine interrupted copulation ferrets (one failed to ovulate), only one animal produced a single blastocyst. The interrupted copulation group averaged 4.4 unfertilized eggs (range 2–10; S.D. = 5.0) per female. Although ferrets ovulated during short copulations, those eggs are not likely to be fertilized.
Oxygen binding of single red blood cells of the annelid bloodworm Glycera dibranchiata
Authors: Mangum C. P. , Colacino J. M. , Vandergon T. L.
Published: June 2005

The red blood cells of the annelid bloodworm Glycera dibranchiata contain two structurally and functionally distinct assemblages of hemoglobin. In the present sample the monomer comprised 57% and the polymer 43% of the total amount. The O2 affinities of the two differ by a factor of about two. Therefore, if the two assemblages occur in different cells, one would expect a bimodal distribution of P50 values for single RBCs and, if they coexist in the same cell, one would expect a monomodal distribution. The distribution is clearly monomodal, indicating no anatomical separation of mono‐ and polymeric hemoglobins.
Chemical access to the vomeronasal organs of the lizard Chalcides ocellatus
Authors: Graves Brent M. , Halpern Mimi
Published: June 2005

A functional association between tongue flicking and vomeronasal organ chemoreception in lizards has been assumed frequently, but never tested. To test this hypothesis, a cotton swab soaked in prey extract mixed with [3H]proline was touched ten times to the snouts of normal and tongueless lizards (Chalcides ocellatus), as well as normal lizards whose vomeronasal organ (VNO) ducts had been sealed with a tissue adhesive. Additionally, such a swab was held approximately 0.5 cm in front of the snout of normal and tongueless lizards for 1 min, which allowed no contact by tongueless animals and tongue contact only by normal lizards. Using autoradiography, substantial and comparable concentrations of labeled molecules were detected in the mouths, VNO ducts, and VNOs of normal subjects in both conditions, as well as tongueless lizards whose snouts made physical contact with swabs. No label was evident in VNOs of tongueless animals that did not contact swabs or normal animals with sealed VN ducts. Labeling was not apparent generally in the olfactory epithelium. These results suggest that: 1) the tongue is not required for, nor does it increase, chemical delivery to VNOs when snout contact occurs; 2) the tongue transfers molecules from the external environment to the oral region; 3) it is unlikely that nonvolatile chemicals reach the olfactory epithelium via an oral route; and 4) tissue adhesive is an effective means of preventing chemical access to the VN organs.
Spermatolysins in Bufo arenarum: Their activity on oocyte surface
Authors: Cabada Marcelo O. , Manes Mario E. , Gomez Marta I.
Published: June 2005

The activity of spermatolysins from Bufo arenarum spermatozoa on spawned dejellied oocytes is studied at structural and ultrastructural levels. After adding spermatolysins to spawned dejellied oocytes, a wrinkling of the animal hemisphere is first observed under a stereomicroscope. Two or three minutes later, the vitelline envelope in the animal hemisphere is completely digested, which produces oocyte flattening. The vitelline envelope covering the vegetal hemisphere is not modified with the treatment. Ultrastructural observations indicate that while the vitelline envelope of the vegetal hemisphere remains unaltered, the animal counterpart gradually loses its components and finally all structures disappear. Scanning microscope observations reveal that the microvilii of the plasma membrane in the animal hemisphere decreases in number and length, while the vegetal region is not altered by the enzyme.
Organic acid (or anion) and organic base (or cation) transport by renal tubules of nonmammalian vertebrates
Authors: Dantzler William H.
Published: June 2005

Organic acids (or anions) and organic bases (or cations) are transported by the renal tubules of nonmammalian vertebrates, but until recently the details of the transport processes have been poorly studied. Work with isolated perfused and nonperfused renal tubules and with membrane vesicles has now begun to supply information on the transepithelial transport processes and the transport steps at the individual cell membranes. The current information is reviewed for organic acids (or anions) as a general group, for urate (which generally appears to be transported by a separate system from that for other organic anions), and for organic bases (or cations) as a general group. Tentative cellular models for the transepithelial transport of each of these general categories of compounds are suggested.
Cytophysiology of growth pulsations in hydroid polyps
Authors: Beloussov L. V. , Labas J. A. , Kazakova N. I. , Zaraisky A. G.
Published: June 2005

Cell orientation and intercellular changes accompanying growth pulsations (GP) have been studied in the marine hydroids Obelia longissima, O. loveni, and Dynamena pumila with the use of time‐lapse filming, mechanography, optical microscopy, and electron microscopy. The extension phase of the GP was correlated with an increase in cell volume and the rotation of cells to a transverse orientation. Tip cells return to an oblique orientation during the retraction phase via a rapid (about 1 μm/second) distalward sliding of external cell poles. In most samples, a proximodistal wave of transversad cell rotations was observed within a period of 30–90 μm/minutes. In contrast, return to the oblique orientation is almost synchronous. The extension GP phase is correlated with extensive cell vacuolization and the retraction phase with fusion of these vacuoles into elongated channels opening into external space.

The extension phase was stabilized in hypotonic medium, isotonic medium with increased NaCl concentration, and by ionic transport inhibitors (which increase cytoplasmic concentration of Na+ and Cl−). GP are arrested in the retraction phase in hypertonic medium, isotonic medium with decreased Na+ and Cl− concentration, and by inhibitors whose decreasing cytoplasmic concentrations of Na+ and Cl− arrest GP in the retraction phase. These data point out the participation of osmotic mechanisms in the regulation of GP.
Reevaluation of the effects of growth hormone and prolactin on anuran tadpole growth and development
Authors: Delidow Beverly C.
Published: June 2005

The effects of ovine prolactin (oPRL) and ovine (o) or porcine (p) growth hormone (GH) on growth of anuran larvae were compared. In grass frog tadpoles (Rana pipiens), injections of oPRL (10 μg/gm/day) increased tail growth and body weight but had no effect on hindlimb growth or development. The same dose of oGH did not significantly affect the tail or body weight but it caused a striking increase in limb length and development. In bullfrog tadpoles (Rana catesbeiana) given an ergot drug (bromocryptine) to induce metamorphic changes, significant tail regression and loss of body weight occurred. Treatment with oPRL reversed these effects but had no effect on hindlimb growth or development. The pGH was much less effective than the oPRL in blocking tail regression and body weight loss but it significantly increased limb growth and development. These results show that GH and PRL can differentially regulate growth and development of structures in larval anurans. The effects of GH on limb growth and development can not be explained simply by a thyrotropic effect.
In vivo cellular reactions and clearance of bacteria from the coelomic fluid of the marine annelid, Arenicola marina L. (polychaeta)
Authors: Fitzgerald S. W. , Ratcliffe N. A.
Published: June 2005

The coelomocyte reactions of the polychaeta Arenicola marina L. in reponse to experimental infection and the fate of the injected bacteria have been investigated utilizing unlabelled and radiolabelled bacteria. In A. marina, 60–75% of the inoculum is cleared from the coelomic fluid within the first 10 min and this increases to over 95% by 3 h postinjection. These changes appear to be correlated with a reduction of freely circulating coelomocytes and the appearance of cellular aggregates. These clumps serve to contain the bacteria and many are eventually incorporated into “brown bodies” which become necrotic and melanised. Coelomocytes enclosing ingested bacteria also migrate into many of the surrounding tissues. Nephridia too are involved in the removal of bacteria from the coelom either by filtration from the coelomic fluid or, to a lesser extent, by the phagocytotic activity of the cells of the nephridial walls.

Lack of appreciable amounts of free radiolabel in the coelomic fluid indicates that humoral bacteriolysins do not play a major role in the clearance process.
Sites of zona pellucida shedding by mouse embryo other than muran trophectoderm
Authors: Yamazaki Kimie , Kato Yoshihiro
Published: June 2005

The sites at which a mouse embryo sheds the zona pellucida in preparation for its hatching were investigated in vitro. Of all cases examined, 24% shedding occurred at the mural site, 24% at the inner cell mass site, 17% at the equatorial site, and 35% at other sites. It thus appears reasonable to conclude that there is no particular site destined for shedding and the site at which it does take place in vitro is irrelevant to that at which the uterus later becomes attached. Expressing its frequency in terms of a unit of area indicated shedding to occur markedly at the axis penetrating the inner cell mass and mural trophectoderm. The ratio of hatching frequency along this axis to that at other areas was determined as 7:1.
Nosema kingi: Effects on fecundity, fertility, and longevity of Drosophila melanogaster
Authors: Armstrong Earlene , Bass Linda K.
Published: June 2005

The effects of Nosema kingi on the fecundity, fertility, and longevity of Drosophila melanogaster were investigated. These studies revealed that parasitized D. melanogaster lay significantly fewer eggs and produce fewer offspring than nonparasitized flies. Although males tended to live longer than females, the life span of both sexes of infected D. melanogaster was significantly reduced.
Activation of fat body glycogen phosphorylase in the eastern lubber grasshopper (Romalea microptera) by the endogenous neuropeptides Ro I and Ro II
Authors: Gäde Gerd , Spring Jeffrey H.
Published: June 2005

Romalea corpus cardiacum (CC) contains large quantities of two neuropeptides, named Ro I and Ro II, that are capable of eliciting strong hyperlipemic (locusts) and hypertrehalosemic (cockroaches) responses in test species (Spring and Gäde: Journal of Experimental Zoology 241:41–50, 1987). Although clearly members of the locust adipokinetic hormone/crustacean red pigment‐concentrating hormone (AKH/RPCH) family of peptides (Gäde: Zeitschrift für Naturforschung, Section C 41:315–320, 1986), these neuropeptides have no discernible effect on hemolymph lipids or carbohydrates in Romalea itself, and neither do large doses of synthetic locust AKH I (1,000 pmol) nor stick insect hypertrehalosemic factor II (HTF II: 500 pmol). Injections of its own CC are capable of stimulating Romalea fat body glycogen phosphorylase in a dose‐dependent manner, and this effect can be mimicked by Ro I and Ro II. Neither extracts of pars intercerebralis nor subesophageal ganglion have any significant effect on phosphorylase activation. Using synthetic peptides, we determined dose‐response curves for phosphorylase activation. Ro I is the more effective in stimulating phosphorylase, with a maximum activation of 70%, compared to 50% for Ro II. Ro II is more potent, however, producing a significant activation with 0.1 pmol, compared to 0.5 pmol of Ro I. Although these peptides are powerful activators of endogenous fat body glycogen phosphorylase in Romalea, this function does not explain the enormous quantities of neuropeptide (2,800 pmol Ro I; 650 pmol Ro II) found in the CC. Glycogen phosphorylase is also activated by starvation, and this effect is reversed by feeding. It is not clear at present whether the starvation‐induced activation is hormonally controlled.
Thyroid hormones in trout reproduction: Enhancement of gonadotropin‐releasing hormone analogue and partially purified salmon gonadotropin‐induced ovarian maturation in vivo and in vitro
Authors: Sullivan Craig V. , Bernard Melinda G. , Hara Akihiko , Dickhoff Walton W.
Published: June 2005

Maturing female rainbow trout were injected two times with gonadotropin‐releasing hormone analogue (GnRHa) or once with triiodothyronine (T3) alone or in combination. GnRHa treatment caused ovulation within 10 days after the second injection. T3 treatment caused a severalfold increase in blood plasma T3 concentrations and increased the ovulatory response to GnRHa. Ninety percent of the fish injected with both T3 and GnRHa ovulated within 3 days after the second GnRHa injection, as opposed to 50% of the fish injected only with GnRHa, or 25% of the controls. In all groups total androgen (TA) and 17α‐20β‐dihydroxy‐4‐pregnen‐3‐one (DHP) levels increased and estradiol (E2) levels decreased between the time of the first injection and the time of spawning. GnRHa decreased TA levels and increased thyroxine and T3 levels, but did not affect either E2 or DHP concentration in the blood plasma of the fish at the time of spawning. To investigate the mechanism of action of T3 on trout maturation, oocytes within intact follicles were cultured in the presence of various concentrations (0.1 to 1,000 ng/ml) of partially purified salmon gonadotropin (SG‐G100) with or without various concentrations (0.5 to 500 ng/ml) of T3. The lower concentrations of T3 (0.5 to 50 ng/ml) potentiated oocyte maturation (germinal vesicle breakdown [GVBD]) in response to SG‐G100. The highest concentration of T3 inhibited GVBD. T3 was effective in increasing GVBD only at the lowest concentration of SG‐G100 (10 ng/ml) that was effective in stimulating GVBD. The percentage of oocytes that had undergone GVBD was positively correlated with the concentration of DHP in the culture medium. These results suggest that thyroid hormones may influence final maturation of trout by potentiating the steroidogenic responses of the ovary to gonadotropin.
Determination of cell death in the developmental process of anuran larval skin
Authors: Kinoshita Tsutomu , Takahama Hideki , Sasaki Fumie , Watanabe Kyozo
Published: June 2005

In metamorphosis of anuran tadpoles, tail skin degenerates concomitantly with tail resorption, whereas back skin develops from larval to adult type. Such a difference in developmental fate of the tadpole skin is called regional specificity. To examine when cell death of tail skin is determined during development, prospective skins of embryos or larval skins were reciprocally transplanted between back and tail of the same animal at various developmental stages. Operated animals were reared until the end of metamorphosis, when the phenotypic expression of the grafts was examined. Regional specificity could not be observed in most of the tadpoles that were operated at the neurula stage. However, specificity‐positive cases were found among the animals operated during a period from late neurula to tail‐bud stage. This period corresponded to the developmental stage prior to the appearance of basal lamina and collagen fibers of the skin. When skins were grafted at larval stages after hatching, almost all of the operated tadpoles showed the regional specificity in graft areas of both tail and back. In order to determine the cell type that is responsible for the developmental fate of skin, cell blocks dissected from ectoderm or dermatome of mesoderm were reciprocally transplanted between presumptive regions of back and tail at the tail‐bud stage. The developmental fate of the skin in the operated areas was significantly altered by mesodermal but not by ectodermal transplantation. These results suggest that the developmental fate of anuran larval skin, especially cell death of tail skin, is determined by factors contained within the dermatome at embryonic stage preceding tail‐bud formation.
Changing localizations of site‐specific sperm surface antigens during sea urchin fertilization
Authors: Nishioka David , Gorman Elizabeth A. , Ward Rita D.
Published: June 2005

Indirect immunofluorescence studies show that monoclonal antibody (mAb) J18/2 binds site‐specifically to surface antigens localized over the acrosome and tail regions of mature Strongylocentrotus purpuratus spermatozoa. Within 5 min after induction of the acrosome reaction by exposure to egg jelly or ionophore A23187, these surface antigens become detectable over the lateral region of the head so that the entire surface of the spermatozoon is labeled. Polyspermically fertilized S. purpuratus eggs fixed at varying times after insemination and exposed to mAb J18/2 reveal that these surface antigens are quickly incorporated into the egg plasma membrane and begin to disperse as early as 1.5 min after insemination. At subsequent times, they undergo further dispersal so that by 45 min they are distributed over the entire surface of the egg. These results suggest that the sperm surface components recognized by mAb J18/2 gain the ability to disperse laterally during the acrosome reaction and proceed to do so in the egg plasma membrane after fertilization.