bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of excising the apical ectodermal ridge on the development of the marginal vasculature of the wing bud in the chick embryo
Authors: Feinberg Feinberg Richard N. , Saunders John W.
Published: June 2005

The limb bud of the chick embryo depends for its outgrowth on an interaction between the apical ectodermal ridge (AER), which rims the apex of the bud, and the subjacent limb bud mesoderm. This report describes the results of experiments that were designed to test whether a relationship exists between the AER and the origin of the distinctive marginal veins, which drain the early arterial supply and capillary bed of the wing bud. All of the AER or localized portions of it were excised from wing buds of embryos at stages 17–23. Effects of the operation on the vascular pattern were analyzed in specimens whose blood vessels were injected with India ink at appropriate postoperative intervals. Excision of all or part of the AER at stages prior to the formation of the marginal vein results in complete or partial failure of the marginal veins to form, depending on the extent of ridge deletion. Once the marginal vein is formed proximally, however, it persists proximally even after the AER is removed, but distally it fails to form. Limb bud mesoderm, encased in backskin ectoderm and grafted to a host embryo, fails to form a marginal vein, indicating that nonridge ectoderm will not substitute for the AER in promoting normal vascularization. Isolated limb buds grafted to the chorioallantoic membrane with their normal ectodermal covering show normal vasculogenesis, indicating that the vascular pattern of the limb is intrinsically determined. These results indicate that the AER is required for the establishment of the marginal veins and the formation of a characteristic vascular pattern in the limb.
Ammonia excretion by the gills of two marine teleost fish: The importance of NH4+ permeance
Authors: Goldstein Leon , Claiborne James B. , Evans David E.
Published: June 2005

Varying the concentration of un‐ionized ammonia (NH3) in the medium perfusing the gills of the isolated fish head while holding the total ammonia (NH4+ + NH3) concentration constant had no significant effect on gill ammonia excretion. In contrast, alteration in the medium NH4+ concentration at a fixed NH3 concentration produced a significant change in ammonia excretion. Thus, gill ammonia excretion was related to medium NH4+, not NH3, concentration.
Ecdysteroid induction of cell surface contacts in a Drosophila cell line
Authors: Yudin Ashley I. , Clark Wallis H. , Chang Ernest S.
Published: June 2005

Drosophila Kc cells are usually spherical in shape and are relatively free of cell‐cell contacts. Soon after exposure to 20‐hydroxyecdysone they develop extensions, assume a fibroblastic shape, and closely adhere to adjacent cells by means of cell‐cell contacts to form large multicellular aggregates. This adhesive nature is enhanced with trypsin treatment without disruption of cell shape. Simultaneous addition of 20‐hydroxyecdysone and juvenile hormone results in diminished aggregate formation without preventing the changes in cell shape. These factors point to the possibility that 20‐hydroxyecdysone stimulates modifications in the cell surface that may be important during embryological differentiation.
Effect of developmental stage and body size on oxygen consumption of anuran larvae: A reappraisal
Authors: Feder Martin E.
Published: June 2005

The rate of oxygen consumption (V̇) varies throughout metamorphosis in larvae of anuran amphibians. To determine whether variation in V̇ is best explained by variation in developmental stage (S), dry body mass (M), or their interaction, I measured V̇ in developmental series of four species. In all species M accounted for most (59–90%) of the variation in V̇. Developmental stage has relatively little effect on V̇ after appropriate correction for differences in M among samples; S accounted for no more than 2% of the variation in V̇ in two genera (Bufo, Rana) and no more than 7% in a third (Hymenochirus). Late stages of metamorphosis were not examined in these larvae. In Xenopus larvae, S has little effect upon V̇ until late stages of metamorphosis, in which some but not all larvae had reduced V̇. The general relationship between V̇ and M in anuran larvae at 25°C is V̇ = 3.1 M0.827, where V̇ is in μl O2 STPD ·hr−1 and M is in mg. Because the exponent of M, 0.827, is less than 1.0, expression of V̇ as V̇ ·M−1 fails to correct for differences in M in statistical analyses. Most prior studies of larval V̇ require reevaluation because of statistical and methodological problems.
Flight muscle development in a hemimetabolous insect
Authors: Ready Neal E. , Josephson R. K.
Published: June 2005

The size of the metathoracic dorsal longitudinal flight muscle (DLM) in the cricket Teleogryllus oceanicus remains a constant proportion of metathoracic volume during most of nymphal life. Between the middle of the last nymphal instar and the fifth day of adult life, the DLM grows more rapidly than the metathorax, so that the ratio of DLM weight to metathoracic volume increases by a factor of 4. During this time, the DLM changes in appearance from translucent to pink, indicating an increase in mitochondrial content. Isometric twitch duration remains unchanged through late nymphal and early adult life (21 msec, onset to 50% relaxation, 25°C), as does fusion frequency (approximately 100 Hz, 25°C). During late adult life, DLM size decreases to 13% of the average for a young adult, isometric twitch duration doubles, and the DLM changes in appearance from pink to white. Since the flight motor program develops late in nymphal life and wings are produced only at the terminal molt, contraction kinetics that are characteristic of adult flight muscles appear to develop before the DLM receives the neural activity pattern for or becomes functional in flight. The appearance of adult contraction kinetics is apparently controlled by factors different from those that control increase in muscle size and mitochondrial content, since these processes are temporally separated during development.
The agouti suppressor (As) coat color mutation in mice: Developmental effects on the expression of agouti locus alleles
Authors: Poole Timothy W.
Published: June 2005

The alleles at the agouti locus in the mouse determine whether eumelanin or pheomelanin is synthesized by the follicular melanocytes. The agouti suppressor (As) mutation, which is closely linked to the agouti locus, reduces the amount of pheomelanin produced by whatever agouti alleles are present in the animal's genome. Previous developmental studies have indicated that the agouti alleles exert their influence on the follicular melanocytes via interactions between the developing dermis and epidermis. Using the techniques of dermal‐epidermal recombination of embryonic agouti suppressor (AsAw/AsAw), white‐bellied agouti (Aw/Aw), yellow (Ay/a), viable yellow (Auy/Auy), black and tan (at/at), and nonagouti (a/a) mouse skin, the present study demonstrates that 1) the dermis is responsible for the development of regional pigmentation patterns in white‐bellied agouti mice, and 2) the agouti suppressor mutation interferes with the expression of the white‐bellied agouti allele by acting on the dermis as well as the epidermis. In addition, this study provides further evidence for the role of the epidermis in the expression of the agouti locus alleles.
Chicken fetal antigen: Association with lymphoid development and differentiation
Authors: Dietert R. R. , Lewin H. A. , Qureshi M. A. , Kass L. B.
Published: June 2005

Rabbit antisera capable of detecting chicken fetal antigen (CFA) was prepared against 1‐day chick red blood cells (RBCs) and made specific by exhaustive adsorption with adult chicken peripheral RBCs (PRBCs) from the same strain. Microcytotoxicity was used to study the incidence of CFA on lymphocytes obtained from several organs at different developmental stages in the chicken. Lymphocyte‐associated CFA (LA‐CFA) determinants and erythrocytespecific CFA (ES‐CFA) determinants were distinguished through the use of adsorption analysis. The high incidence of CFA‐positive lymphocytes found in the fetal bursa and thymus was not equaled in the peripheral organs of the spleen, cecal tonsils, and gland of Harder. CFA expression on adult lymphocytes was restricted to the thymus and peripheral blood. It is suggested that these cells may represent a subpopulation of T lymphocytes. Adult spleen, cecal tonsils, and gland of Harder were virtually devoid of CFA‐bearing lymphocytes. At fetal developmental stages when greater than 94% of the bursal B cells were CFA‐positive, few, if any, of the highly differentiated Harderian B cells possessed CFA. It is suggested that LA‐CFA expression is dependent upon B cell differentiation and/or the bursa (central) vs gland of Harder (peripheral) microenvironment. The pattern of CFA expression on bursacytes is discussed in light of the properties of age resistance and bursal‐dependent target cells associated with virally induced lymphoid leukosis.
Host location by the Japanese beetle: Evidence for a key role for olfaction in a highly polyphagous insect
Authors: Ahmad Sami
Published: June 2005

Olfaction plays a key role in host location and possibly also in host preference in a highly polyphagous insect, the Japanese beetle, Popillia japonica Newman. Moreover, this study also shows for the first time that impairment in olfaction by antennectomy affects feeding intensity. This suggests probable integration of olfactory and gustatory inputs in eliciting maximal/optimal feeding response.
Cell interactions and actin synthesis in mammalian oocytes
Authors: Osborn J. C. , Moor R. M.
Published: June 2005

In this study, we have examined the profiles of proteins synthesized by mammalian oocytes in the presence and absence of cumulus cells. The results show that the patterns of protein synthesis are broadly similar in cumulus‐enclosed and denuded oocytes, but that as a consequence of removing the cumulus cells, the presence of a 45,000‐dalton band is greatly reduced. This band, identified by comigration studies on two‐dimensional polyacrylamide gels as actin, is strongly synthesized in both isolated cumulus cells and in oocytes labeled in the presence of cumulus cells, but is only weakly synthesized by oocytes incubated in the absence of cumulus cells. We suggest that the presence of newly synthesized actin in the oocyte is dependent upon cellular cooperation between the cumulus cells and oocytes.
Presence and possible function of root effect hemoglobins in fishes lacking functional swim bladders
Authors: Ingermann Rolf L. , Terwilliger Robert C.
Published: June 2005

The adult hemoglobins of 15 species of teleost and the midgestation fetal hemoglobin of the seaperch Embiotoca lateralis show a pronounced decrease in oxygen‐carrying capacity at low pH, a Root effect. All of these fishes lack a functional swim bladder, which is generally thought to be the likely site of Root effect hemoglobin function. All of the teleosts examined, including the fetal sea perch, however, have a choroid rete, a structure that is proposed to be involved in oxygen secretion to the eye. The data are inconsistent with the generalization that only fishes with swim bladders possess Root effect hemoglobins, and that the only function of Root effect hemoglobins is in the secretion of oxygen to a swim bladder. The data for the fishes examined in this study suggest that a better correlation may exist between Root effect hemoglobins and the presence of a choroid rete. This is consistent with the hypothesis that Root effect hemoglobins may be involved in the physiology of the eye in many fishes.
Characterization of glycoprotein antifreeze biosynthesis in isolated hepatocytes from Pagothenia borchgrevinki
Authors: O'Grady Scott M. , Clarke Andrew , DeVries Arthur L.
Published: June 2005

Incorporation of 14C‐leucine and 3H‐alanine into TCA‐precipitable protein, TCA‐soluble protein, and antifreeze glycoproteins (AFGP) was measured in isolated hepatocytes from Pagothenia borchgrevinki Boulenger following acclimation to −1.5°C and + 4°C. The rate of 3H‐alanine incorporation into AFGP followed Michaelis‐Menten kinetics with a Vmax of 4.8 nM·mg protein−1·h−1 at −1.5°C and 7.5 nM·mg protein−1·h−1 at + 4°C. Km values were 27.8 μM and 41.7 μM at −1.5°C and + 4°C, respectively. Incorporation of 14C‐leucine into TCA‐precipitable protein also showed Michaelis‐Menten kinetics with a Vmax of 20 nM·mg protein −1·hr−1 at −1.5°C and 32.3 nM·mg protein −1·hr−1 at + 4°C. Km values were 83.3 μM at −1.5°C and 125 μM at + 4°C. AFGP synthesis was monitored over a 120‐h period by radioimmunoassay in cultures of hepatocyes from cold acclimated fish (− 1.5°C) incubated at both − 1.5°C and + 4°C. The estimated Q10 for AFGP from these data is 3.23. Polyacrylamide gel electrophoresis of antifreeze glycoproteins produced by isolated hepatocytes showed that all four antifreeze fractions normally present in the serum of P. borchgrevinki are also synthesized by isolated hepatocytes. The two major conclusions from these experiments were that 1) P. borchgrevinki, unlike many northern fishes, does not show thermal acclimation, and 2) environmental factors responsible for modification of peptide antifreeze synthesis in northern fishes do not elicit changes in AFGP synthesis in P. borchgrevinki.
Collagens from the skin and cartilage of the larval salamander Ambystoma tigrinum
Authors: Smith Gerald N. , Linsenmayer Thomas F.
Published: June 2005

The major collagens of larval salamander (Ambystoma tigrinum) skin and cartilage were purified and characterized by CM‐cellulose chromatography and amino acid analysis of the component α chains. The collagens are similar to type I (skin) and type II (cartilage) collagens of birds and mammals. The type I molecule has the chain composition (α1)2α2, and the type II molecule is an (α1)3 molecule. Both collagens have lower levels of proline hydroxylation than the collagens isolated from homoiotherms, and generally higher serine contents. The type II collagen molecule has about half of its lysine residues hydroxylated, as in cartilage collagens of other species. Cyanogen bromide digestion of the component α chains followed by CM‐cellulose chromatography or SDS gel electrophoresis of the peptides confirms that each chain is a different gene product and allows identification of the collagens in this species. Similar collagens were isolated from newt (Notophthalmus viridescens) tissues by pepsin extraction and fractional salt precipitation. These data will allow more effective utilization of the regenerating salamander limb for studies of collagen metabolism during regeneration.
The effect of primary and secondary immunization on the lymphoid tissues of the carp, Cyprinus carpio L
Authors: Secombes Christopher J. , Manning Margaret J. , Ellis Anthony E.
Published: June 2005

Mirror carp immunized with human gamma globulin (HGG) in Freund's complete adjuvant (FCA) show a proliferative response involving cells whose cytoplasm stains deep red with methyl green‐pyronin (pyroninophilic cells). This response occurs particularly in the haemopoietic parenchyma of the pronephros and mesonephros. It peaks at week 3, with the formation of clusters of pyroninophilic cells in the pronephros. Immunization with Aeromonas salmonicida elicited a less intense pyroninophilic response but caused a larger increase in pigment‐containing cells. After a secondary immunization with HGG in FCA, a distinct response was observed in the spleen: Pyroninophilic cells collected within the ellipsoid sheaths in large numbers and formed nodules. The reticulum of such nodules acquired spherical proportions and resembled the white pulp reticulum of the tetrapod spleen. The roles of such pyroninophilic cells and the possibility that aggregations of them may be functionally analogous to homoiotherm germinal centres are discussed.
Control of contour feather growth of Japanese quail
Authors: Honda H. , Tanaka Kumiko , Minamino T. , Konishi T.
Published: June 2005

Growth of a contour feather on a dorsal spinal tract of Japanese quail was investigated using a logistic model, in which feather length is determined by two factors, growth rate and growth period. Final feather lengths were constant under most experimental conditions including those under which the growth rate decreased while the growth period increased. Another experimental condition was discovered in which a feather elongated owing to an increase in growth period.

Once a feather had fully grown, its length remained constant. After plucking a feather, a new feather grew and its final length was correlated with the old one. Shortening a growing feather by cutting off a distal part did not affect its growth pattern. In addition, shortening a fully grown feather by cutting off the distal part did not activate its follicle. Plucking a feather during growth stopped and erased the present growing phase and initiated feather growth from the beginning to form a complete feather. Repetition of plucking four or five times did not affect the final length of a feather, but did decrease the growth rate, which was complemented by an elongation of the growth period. Feather formation under a short photoperiod condition (8L:16D) resulted in a longer feather which resulted from elongation of the growth period while the growth rate remained constant.
Hydromineral balance in the chick embryo: Effects of hypophysectomy
Authors: Murphy Michael J. , Brown Stephen C. , Brown Patricia Stocking
Published: June 2005

The developing chick embryo exhibits a regular pattern of accumulation and reabsorption of fluid in its extraembryonic compartments. Fluid volume (measured by dye dilution) peaks at Day 14 in both the allantois (12.4 ml) and the amnion (5.1 ml). The standard experimental procedure of removing 2 ml of albumen at 33–36 hr of incubation does not alter this pattern, but leads to a maximum decrease in fluid volume of ca. 1 ml in both amniotic and allantoic compartments. Although [Na] and [Cl] remain essentially constant in the serum, they steadily decrease in the allantois (remaining substantially below serum levels). In the amnion, [Cl] is maintained above that of serum, whereas [Na] falls below serum [Na] by Day 14. In the Day 12 (stage 38) embryo, hypophysectomy (HX) causes a substantial increase in the allantoic fluid volume and [Na] and [Cl], thus resulting in a 166% increase in total Na and Cl over that of sham‐operated embryos. By contrast, HX did not alter amniotic fluid volume, although it did decrease [Na] and to a lesser degree, [Cl]. Serum [Na], but not [Cl], was reduced by HX. HX abolished the normally steep ionic gradients maintained between the allantois and both serum and amnion. Thus, the most dramatic effects of HX at Day 12 are on the allantois, which accumulates both Na and Cl at the expense of the amnion and serum. This suggests that pituitary hormones may normally act by Day 12 to reduce urinary volume and electrolyte excretion and/or to increase fluid and electrolyte reabsorption from the allantois.
Development of embryonic chick oviducts in organ culture under the influences of steroid hormones
Authors: Kiell Charles S. , Cohen Ira T. , Fell Paul E.
Published: June 2005

Explanted oviducts from 13‐ and 16‐day embryonic female chicks responded to estradiol (1 to 4 μg/ml) in the culture medium by forming a thickened epithelium folded into crypts and containing goblet cells and by development of the stroma. In medium containing 3 μg/ml estradiol and 0.125 μg/ml hydrocortisone, 13‐day embryonic oviducts exhibited further development: The columnar epithelial cells formed cilia and tubular glands were formed.
In vivo and in vitro effect of cold on the degree of polymerization of tubulin in toad brain and testis
Authors: Lopez Luis A. , Bertini Francisco
Published: June 2005

The tubulin of both brain and testis of the toad Bufo arenarum was partially depolymerized when the animals were maintained on ice for 90 minutes or 17 hours. Recovery of the animals at room temperature restored the normal degree of polymerization in both organs. Normalization of the polymerization degree also occurred in organs separated from cooled animals and incubated in vitro for 90 minutes at 20°C. When the organs were cooled in vitro, only testicular tubulin underwent depolymerization, and in a degree similar to that occurring by incubation at 20°C. The results suggest that the mechanisms regulating tubulin depolymerization in vivo are different from those taking place in vitro.
Western Fence Lizard (Sceloporus occidentalis) chemical signals. III. An experimental ethogram of conspecific body licking
Authors: Duvall David
Published: June 2005

The loci and frequency of conspecific body licking actions of naturally breeding, adult western fence lizards, Sceloporus occidentalis biseriatus, were catalogued and analyzed in an experimental ethogram procedure. The purpose of the study was to begin to localize regions of the western fence lizard body that might exude or carry conspecific chemical signals, or pheromones, important in social encounters of close physical proximity. Among pairs of males, females, and males and females, male stimulus lizards were licked more than stimulus females on (1) the head and face and (2) the flank‐back region, and this was exhibited equally by both male and female experimental lizards (each pair was composed of an experimental and stimulus lizard). Although male and female stimulus animals were licked equally on their legs, experimental females exhibited higher levels of this action than did experimental males. A few tail licks occurred, but no differences of any type were obtained. The results suggest the possibility that pheromones carried on, or exuded from, certain fence lizard body regions, such as the head and face, for example, may play a releasing or eliciting function in social encounters of close physical proximity. Such cues probably are detected by the tongue‐vomeronasal system.
The adaptive significance of the reversed bohr and root shifts in blood from the marine gastropod, Buccinum undatum
Authors: Brix Ole
Published: June 2005

The adjustments of blood respiratory properties to hypoxic conditions (PWO2 = 30 Torr) have been investigated in relation to salinity acclimation in the marine prosobranch, Buccinum undatum. (1) In whole blood the reversed Bohr effect and the cooperativity of O2 binding are not influenced by acclimation history. (2) Blood from high‐salinity (35%) animals is isoosmotic to the ambient water under normoxic conditions (PWO2 = 150 Torr), but hypoosmotic under hypoxic conditions by a regulated decrease in the Cl− ion concentration of about 90 mM. The lower [Cl−] induces, via the reversed Root effect, an approximate doubling of the amount of hemocyanin‐bound oxygen, when blood pCO2 is increased in the range 1 to 8 Torr. (3) Blood from low‐salinity (20%) animals is also isoosmotic to the ambient water under hypoxic conditions, and the reversed Root effect is present under both normoxic and hypoxic conditions. (4) At both high and low salinity no change in blood hemocyanin concentration is seen in hypoxiaacclimated animals.
Roles of ectodermal and endodermal epithelial cells in hydra morphogenesis: Construction of chimeric strains
Authors: Wanek Nancy , Campbell Richard D.
Published: June 2005

A method is described for constructing chimeric hydra that consist of ectoderm from one strain of hydra and endoderm from a different strain. A ring of vitally stained tissue (ectoderm and endoderm) is grafted into an unmarked polyp. Differential movement of the ectoderm and endoderm eventually results in chimeric regions which are visible as marked ectoderm overlying unmarked endoderm and unmarked ectoderm overlying marked endoderm. These chimeric regions are then excised and each is allowed to regenerate, forming a whole chimeric animal. Isolated chimeric regions smaller than 0.5 mm in length were grafted into nitrogen mustard treated animals as hosts for in vivo culturing. Reciprocal chimeras between the 40L strain of H. magnipapillata (40L) and H. attenuata (Ha) were used to illustrate the effectiveness of the method for constructing chimeras. These two strains are different in body morphology, size, and color. The [40L ectoderm/Ha endoderm] chimera has 40L shape but is the size and color of Ha. The [Ha ectoderm/40L endoderm] chimera resembles Ha in body shape but is the size and color of 40L. The stability of these traits indicates that the original parental lineage of the epithelial cells is maintained in the chimeric hydra.
Effect of augmentation of nerve supply upon limb regeneration in the chick embryo
Authors: Fowler Ira , Sisken Betty F.
Published: June 2005

Limb regeneration was induced in 4‐day chick embryos by implanting stage 15 neural tube into the amputated stump of the limb. In control animals, amputation alone or amputation with implant of either notochord or somites resulted in development of proximal wing segments only. In experimental animals, more than one‐fourth of the animals containing viable neural tube implants developed proximal, middle, and distal limb segments. These regenerated limb segments contained muscle groups, cartilage models, and nervous structures that approximated the normal situations. Since some new parts regenerated in more than one‐fourth of the cases, it may be concluded that augmentation of nerve supply is an effective method of inducing regeneration in limbs of chick embryos. Volume measurements of the neural tube implant indicate that a “critical mass” of nerve tissue may be necessary for regeneration to occur.
Studies on cockroach flight: The role of continuous neural activation of non‐flight muscles
Authors: Fourtner C. R. , Randall J. B.
Published: June 2005

The primary purpose of this study was to identify the muscles active during flight and determine their temporal relationships in the flight‐cycle, thereby laying the foundations for further investigations of the neural control of flight in the cockroach. The wing‐beat frequency of tethered roaches and the frequency of the flight‐cycle in restrained animals was similar, varying between 23 and 30 beats/second. Intracellular recordings of metathoracic and metacoxal muscle were made simultaneously with electromyograms from the elevators of the wing. Muscles 155, 157, 161, 162, 163, 177A, and 174‐6 were active near the onset of elevator activity; muscles 153, 154, 164, 165, 167, 169, and 177C were active approximately 180° out of phase with the elevators. Muscles 177A and 177C, bifunctional in nature, act as antagonists during flight and as synergists to extend the femur. Since the femur is held flexed during flight, the activity of the femoral flexors, 181A‐C and 182C, was determined during flight. 181A and B showed a bimodal phase distribution while 181C and 182C was almost continuously active during flight. Therefore, the flight‐motor‐program reciprocally drives the elevators and depressors and can continuously drive the motor‐neuronal pool operating the femoral flexor. This continuous drive fixes the femur and permits 177A and 177C to act on the thoracic box.
Time course of changes in fatty acid composition of gills and liver from rainbow trout (Salmo gairdneri) during thermal acclimation
Authors: Sellner Peggy A. , Hazel Jeffrey R.
Published: June 2005

Rainbow trout (Salmo gairdneri), acclimated to 5°C or 20°C, were reacclimated to water of the opposite temperature. The time course of alterations in fatty acid composition of microsomes from gills and liver was monitored over a 28‐day period. Two to six days were required for maximum changes in fatty acid levels with acclimation to 20°C, whereas 10—17 days were required in the opposite direction. Fatty acids from gill microsomes had lower U/S (ratio of unsaturates to saturates) and UI (unsaturation index) and a shorter average chain length than liver microsomes; these differences were preserved with acclimation. In both tissues the U/S, UI, and chain length increased with cold adaptation and decreased with warm adaptation. In gill microsomes, changes in UI and U/S were due primarily to altered levels of saturated fatty acids and 20:4 (n‐6) and 20:5 (n‐3). The latter two acids, products of the Δ5 desaturation step in PUFA biosynthesis, also contributed to the changes in unsaturation indexes were initially mediated by large but transient changes in levels of saturates and monoenes, whereas changes in polyunsaturated fatty acids of the n‐6 and n‐3 families were delayed 3—6 days. Thus, changes in fatty acid composition that accompany acclimation to a different temperature can be resolved into those metabolic reactions (e.g., Δ5 desaturation) that are of major importance and, in the liver, into temporally more than one mechanism (e.g., altering monoenes and PUFA at different times).
Urea cycle enzymes and glutamate dehydrogenase in Xenopus laevis and Bufo viridis adapted to high salinity
Authors: Lee Anina R. , Silove Michelle , Katz Uri , Balinsky John B.
Published: June 2005

Xenopus laevis was adapted stepwise to 600 m osmolar sodium chloride. After adaptation, the level of argininosuccinate lyase was raised 9‐fold, carbamoylphosphate synthetase 6‐fold, and ornithine carbamoyltransferase and arginase 3‐fold. Liver glutamate dehydrogenase was also raised 5‐fold; kidney glutamate dehydrogenase was unchanged. In Bufo viridis similarly adapted, there was a 5‐fold increase in argininosuccinate lyase. When Xenopus laevis was adapted to 600 m osmolar sucrose, there was only an increase in argininosuccinate lyase, and that was only 2.4‐fold. This indicates that the increases in urea cycle enzymes are at least in part responses to sodium chloride rather than just to osmotic stress.
Muscle protein phenotypes and the probable evolutionary origin of a unisexual fish, Poecilia formosa, and its triploid derivatives
Authors: Monaco Paul J. , Rasch Ellen M. , Balsano Joseph S. , Turner Bruce J.
Published: June 2005

Several species‐specific proteins have been identified by polyacrylamide gel electrophoresis (PAGE) of skeletal muscle extracts from the diploid gynogen, Poecilia formosa, its related triploid unisexuals, and their sympatric, bisexual species, P. mexicana and P. latipinna. These water‐soluble, low molecular weight proteins (7,000‐13,000) comigrate with a fraction of purified rabbit parvalbumin on nondenaturing gels and show staining properties similar to rabbit parvalbumins. The electrophoretic patterns of these muscle proteins provide a set of distinctive phenotypic markers for each of the host species involved in naturally occurring breeding complexes with P. mexicana × P. latipinna show no evidence of sexual dimorphisms. Furthermore, the hybrid phenotypes are those that would be predicted from appropriate combinations of parental alleles at three gene loci. The patterns found by PAGE for several generations of pedigreed stocks of P. formosa show strictly matroclinous inheritance of a characteristic muscle protein phenotype and coupled with the electrophoretic patterns of several enzymic proteins reflect the probable hybrid origin of this diploid unisexual. Finally, paternal contributions by P. mexicana to the hybrid genome of triploid unisexuals are clearly demonstrated by comparative analyses of muscle protein phenotypes for P. formosa and its contemporary host species. Our identification of distinctive phenotypic markers in the muscle proteins of several poeciliid species involved in unisexual‐bisexual breeding complexes provides an important new tool for further studies on the adaptive significance of unisexuality, hybridization, and fixed heterozygosity in the evolutionary biology of these fishes.
Peptidase lsozymes of the leopard frog Rana pipiens: Properties and genetics
Authors: Wright David A. , Richards Christina M.
Published: June 2005

The substrate specificity of five peptidases in tissues of the leopard frog, Rana pipiens, corresponds to mammalian peptidases (Pep) A, B, C, D, and S. The inheritance of electrophoretic variants of Pep A, B, C, and D verifies the genetic basis of the variants and the control of the enzymes by separate genetic loci. Electrophoretic patterns of heterozygotes suggest that Pep A, B, and D are dimers, whereas Pep C has a monomer structure. The tissue distribution and developmental patterns suggest that frog peptidases are subject to cellular regulation. Tests of genetic linkage show independent assortment for Pep A and Pep C and for Pep C and Pep D. Pep C is closely linked to superoxide dismutase‐1 (6.87% recommbination), and Pep B is linked to mannose phosphate isomerase (30.4% recommbination).
Effects of eyestalk removal in crabs: Relation to normal premolt
Authors: Spaziani Eugene , Ostedgaard Lynda S. , Vensel William H. , Hegmann Joseph P.
Published: June 2005

Thirty‐six measured variables were compared in crabs de‐eye‐stalked (DE) for 24 hours to 45 days and with normal animals well advanced in the premolt stage of the molting cycle. DE crabs generally differed from premolts in water and ion composition of carapace and blood, but not in organ water content, and differences were independent of time after DE. Furthermore, acute (24‐hour) DE animals displayed 30‐fold higher uptake of cholesterol‐14C in Y‐organs (four to fivefold higher in hepatopancreas and hypodermis) than premolts; uptakes dropped to premolt levels in long‐term DE animals. It is concluded that acute and long‐term de‐eyestalking induce abnormalities in several physiological parameters but also induce changes in cholesterol processing suggestive of normal early and late premolt stages, respectively.
Cellular proliferation in the skin of x‐rayed newt limbs (with a note on x‐ray‐induced limb regression)
Authors: Wertz Richard L.
Published: June 2005

Left hind limbs, including the pelvis, of adult newts (Notophthalmus viridescens) were locally irradiated with a dose of x‐rays that inhibited regeneration (2,000 R). This x‐ray dose and other doses (700‐2,000 R) capable of inhibiting limb regeneration also cause limb regression prior to amputation. Before limb regression occurred, there was a latent period of 3 to 6 weeks. Limb regression was characterized by necrotic wasting and resorption of distal elements. The degree of loss was variable and dependent upon dosage. After this further degenerative changes were not noted. Proliferation of epidermal cells was examined 4 days after irradiation prior to limb regression or after x‐ray‐induced degeneration of the limbs had ended. Proliferative activity in x‐ray limbs was also compared at various stages of contralateral control limb regeneration. Limbs examined after x‐ray‐induced limb regression had ended showed levels of [3H]‐thymidine incorporation into DNA comparable to normal epidermis. In contrast, limbs examined 4 days after irradiation had lower levels of DNA synthesis (P ≪ 0.01). Amputation of limbs in both groups caused an increase in DNA synthesis (P ≪ 0.01). Histological examination showed that cellular proliferation was associated primarily with the epidermis. These results indicate that epidermal cell proliferation was not resistant to x‐rays. However, levels of normal cell division were observed after amputation or after cessation of x‐ray‐induced limb regression.
Properties of an oviducal protein involved in amphibian oocyte fertilization
Authors: Miceli Dora C. , Fernandez Silvia N.
Published: June 2005

The secretion produced at the most cephalic portion of the oviduct of the toad (pars recta in Bufo arenarum) is involved in fertilization. Although the present study indicates that a prerequisite for the fertilization of coelomic eggs is either their passage through the pars recta (PR) or their treatment with PR secretion fluid prior to insemination, the exact role of this secretion in the fertilization process is still not clearly understood. A protein acting upon the vitelline envelope (VE) of Bufo arenarum coelomic eggs has been purified from secretion fluid (pars recta protein, PRP). Some properties of both this protein and the secretion fluid are examined in an effort to understand their mechanism of action. It was shown that PRP partially dissolves the VE of coelomic oocytes in a way that resembles the action of proteolytic enzymes. PRP has also proved to be active on synthetic substrates of proteolytic enzymes such as p‐Tosyl‐L‐arginine methyl ester‐HCl (TAME), α‐N‐benzoyl‐L‐arginine ethyl ester‐HCl (BAEE), and α‐N‐benzoyl‐DL‐arginine‐p‐nitroanilide HCl (BAPNA). PR enzyme is activated by calcium ions, shows a broad peak of maximum activity at pH 7.8, is stable at alkaline pH, and is inhibited by soybean trypsin inhibitor (SBTI) and N‐α‐p‐tosyl‐L‐lysine chloromethyl ketone HCl (TLCK) but not by lima bean trypsin inhibitor (LBTI) or L‐1‐tosyl‐amide‐2‐phenylethylchloro‐methyl‐ketone (TPCK).
Sperm nuclear decondensation in Barnea candida (Mollusca, Pelecypoda) oocytes does not require germinal vesicle breakdown
Authors: Dubé FrançLois , Dufresne‐Dubé Louise , Guerrier Pierre
Published: June 2005

Barnea candida oocytes, submitted to D‐600 (100 μM) 15–20 seconds after insemination in order to inhibit Ca++ uptake but not acid release, fail to exhibit germinal vesicle breakdown (GVBD) whereas penetrated spermatozoa are able to decondense normally. Oocytes transferred in 100 mM Na‐acetate seawater at pH 6.3, 1 minute after insemination, in order to inhibit acid release, fail to undergo GVBD and sperm nuclear decondensation. Upon return of these oocytes to normal seawater and treatment with an excess of KCl, they exhibit GVBD and decondensed sperm nuclei are seen within their cytoplasm. These results show that sperm nuclear decondensation does not require GVBD or Ca++ uptake but may be related to an intracellular pH increase.
Significance of periodic fluctuations in the haemolymph proteins and their catabolic products during starvation and repeated injury in Scylla serrata (Forskal)
Authors: Subhashini M. H. , Ravindranath M. H.
Published: June 2005

The fate of haemolymph proteins during the course of prolonged starvation was investigated. Two different experimental protocols were set up. In experiment 1, sampling of the haemolymph was done in a group of six crabs at 3‐day intervals up to 33 days (group 1). In experiment 2, separate groups of crabs were sampled at 3‐day intervals up to 33 days (group 2).

There is no change in body weight. The haemolymph volume and water increase significantly indicating hydration of haemolymph. The haemolymph protein concentration and quantity decline significantly in both groups during the course of prolonged starvation. Concomitantly, the haemolymph free amino acids concentration and quantity increase in both the groups, indicating degradation of protein during the course of starvation.

That degradation of protein cannot occur continuously but rather takes place on specific days in both groups is indicated by the increase in the products of protein catabolism—namely, free amino acids and ammonia. The results also provide evidence for the mobilization of proteins from storage sites. Nonprotein dry weight increases markedly during the course of starvation, the significance of which is discussed.
Timing of X‐chromosome inactivation is stage dependent rather than age dependent
Authors: Kratzer Paul G.
Published: June 2005

The timing of X‐chromosome inactivation was compared in two mouse strains that differ in their rates of development. The occurrence of X inactivation was measured by dosage changes for the X‐linked enzyme hypoxanthine phosphoribosyl transferase. It was found in intrastrain and reciprocal hybrids that X inactivation was dependent on morphological stage and not on the age of the embryo.
Purification and physical properties of arginase from Xenopus laevis
Authors: Peiser Liora , Balinsky John B.
Published: June 2005

Arginase from the liver of Xenopus laevis has been purified to homogeneity by heat treatment, acetone fractionation, and isoelectric focussing. The main component had an isoelectric point (I.E.P.) of 7.3; there is a minor component of I.E.P. 7.8. The molecular weight of the enzyme, as determined by gel filtration on Sephadex G200, is 76,000 daltons, substantially less than that of rat liver arginase studied concurrently. The molecular weight of the subunits, as determined by electrophoresis in sodium dodecyl sulfate, is 18,000 daltons, again less than that of rat liver arginase. The data indicate that Xenopus liver arginase, like rat liver arginase, is a tetramer. The molecular weight of arginase from adult Xenopus laevis corresponds to that from larval Rana esculenta.
Characterization of spermatid/sperm basic chromosomal proteins in the genus Xenopus (Anura, Pipidae)
Authors: Mann M. , Risley M. S. , Eckhardt R. A. , Kasinsky H. E.
Published: June 2005

Spermatid/sperm basic chromosomal proteins from 17 species and subspecies of the genus Xenopus (Anura, Pipidae) were compared. Electrophoresis on acetic acid/urea/Triton X‐100 polyacrylamide gels revealed that each Xenopus species with a diploid chromosome number of 36, 72, or 108 showed multiple, diverse spermatid/sperm‐specific basic chromatin proteins with mobilities greater than the somatic histones. The numbers and mobilities of these proteins were characteristic of each Xenopus species and each subspecies of Xenopus laevis. Cytochemical tests revealed that the sperm basic nuclear proteins of these Xenopus species and subspecies were rich in arginine and lysine and contained more arginine than the nuclear proteins of somatic cells.

X. tropicalis (2n = 20) and X. sp. n. (Zaire) displayed spermatid/sperm‐specific basic chromatin proteins which migrated within the histone H1 region of acetic acid/urea/Triton X‐100 polyacrylamide gels. Cytochemically the sperm nuclei of these species resembled those of somatic cells.

These observations suggest that spermatid/sperm basic nuclear proteins can be used as molecular markers for individual species and subspecies of the genus Xenopus.
Water balance and apparent oocyte resorption in desert millipedes
Authors: Crawford C. S. , Warburg M. R.
Published: June 2005

Oosorption in response to desiccation stress was tested in spirostreptid millipedes from arid environments. Seasonally collected and experimentally stressed adult females were examined for penetration of oocytes by trypan blue, for compartment levels of water in cuticle + tissue and gut + gut contents, and for hemolymph osmolalities.

Archispirostreptus syriacus from the winter‐rainfall Judaean and Negev deserts decreased in total body water during the hot dry summer. Simultaneously, water in cuticle + tissue and in gut + gut contents increased and decreased respectively in proportion to total water. Water in both compartments decreased in starved specimens exposed for 19 days to 76% relative humidity; these millipedes resorbed a higher percentage of oocytes than did field controls but not more than specimens in saturated air.

Groups of starved premolt (spring) and postmolt (summer) Orthoporus ornatus from New Mexico (summer rainfall) each responded differently when exposed to humidities found in their respective habitats. Compartment water levels in the former remained constant for 19 days under moderate conditions; they declined in the latter after 36–42 days of relative moisture stress. Neither stage showed increased oosorption over field controls when exposed to seasonal humidity ranges.

Archispirostreptus syriacus resorbed a higher proportion of oocytes than did O. ornatus, which matured oocytes only in summer rather than most of the year. Patterns of oosorption and oocyte development probably reflect species‐specific life histories and relative states of starvation rather than seasonal water balance and desiccation stress.
Mechanisms of water vapor absorption in insects
Authors: Machin John , O'Donnell Michael J. , Coutchié Pamela A.
Published: June 2005

Vapor absorption is the mechanism by which specially adapted terrestrial arthropods expend energy to escape from conventional equilibria, dictated by the difference between water activity of the body fluids (aw = 0.99) and the environment. vapor absorbers have an identifiable “condensing” or “carrying” fluid compartment with significantly lower activity. The sites of vapor uptake may be limited to mouth or rectal regions because the mechanisms have probably evolved by modifying existing water transport systems. Morphometric analysis of condensing structures have helped understand the vapor uptake mechanism in Arenivaga and tenebrionid larvae. Activity lowering of condensing fluid is accomplished either by solute‐independent capillary condensation or by solute transport. Linear absorption kinetics, shown by the better‐known vapor absorbers, is achieved by flow‐modulated fluid or ion transport. Comparative studies may help identify anomalous uptake mechanisms worth further study and predict where other examples of the phenomenon may be found.
Pattern regulation during regeneration of embryonically produced symmetrical forelimbs in the axolotl, Ambystoma mexicanum
Authors: Tank Patrick W.
Published: June 2005

Embryonic axolotls (Stages 32–34) underwent surgery during which a graft of flank tissue was transferred from a donor animal to the anterior margin of the forelimb field in a host animal. Double‐posterior forelimbs containing from one to eight digits developed. These limbs were amputated at a level proximal to the elbow to assess their regenerative ability. The majority (62%) of these limbs failed to regenerate externally visible structures. Symmetrical limbs bearing five digits or more than five digits regenerated with greatest frequency (54%). Symmetrical forelimbs bearing four digits or fewer than four digits regenerated less frequently (31%). All regenerates displayed double‐posterior symmetry and usually contained fewer digits than were present in the original limb. The significance of these findings is discussed in the context of a current model for pattern regulation in epimorphic fields.
Enzyme clusters during the metamorphic period of Ambystoma mexicanum: Role of thyroid hormone
Authors: Lamers Wouter H. , Mooren Piet G. , De Graaf Andre , Charles Rob
Published: June 2005

Enzyme activities and DNA content have been measured in axolotl liver during the metamorphic period (4–8 months after spawning). Three different types of enzyme activity profiles were observed. In the type I profile (carbamoyl‐phosphate synthase, arginase, ornithine transcarbamoylase, and glutamate dehydrogenase) enzyme activity is high in the youngest animals studied, and shows a minimum at 5 months followed by a maximum at 8 months of age. Thereafter activities do not change or slightly decrease. In the type II profile (tyrosine aminotransferase, glucose–6–phosphatase) enzyme activity shows a peak at 5 months of age and is low thereafter. Hexokinase, the enzyme with a type III profile, shows high activity throughout the metamorphic period. DNA content remains high throughout the metamorphic period but decreases 50% between 9 and 12 months of age, probably due to an increase in the size of the hepatocytes. No glucokinase activity was detected. High activities of cluster II enzymes represent early metamorphic events, while the rising part of cluster I is associated with late metamorphic events.

The apparent molecular specific activity increases during natural development between 5 and 9 months of age, or precociously, upon thyroid hormone treatment. This change in apparent molecular specific activity is correlated to the advent of ureotelism.
Cytochemical localization of adenylate cyclase activity in planarian tissues
Authors: Pascolini Rita , Gargiulo A. M. , Spreca A. , Ceccarelli P.
Published: June 2005

Cytochemical studies of adenylate cyclase activity were performed on Dugesia lugubris s.l. to ascertain which cell types, among the heterogenous cell population, showed significant adenylate cyclase activity on their plasma membranes.

Nondecapitated worms and cephalic regenerants were examined in replicated experiments. Evidence of adenylate cyclase activity was noted in secretory tissues and the protonephridial system of non‐operated worms, and also in dedifferen‐tiating and regenerating tissues of operated worms. Observations presented in this study call attention to the role of adenylate cyclase in some of the main physiological processes of triclads, such as secretion, excretion, and regeneration.