bluuebunny/crossref_metadata_2025 huggingface dataset:
Regeneration in the sea cucumber Leptosynapta. II. The regenerative capacity
Authors: Smith Gerald N.
Published: June 2005

The dependence of survival and regeneration in the holothuroid Leptosynapta crassipatina (Apoda) on the oral complex—the mouth, the nerve ring, the calcareous ring, and the water vascular system—was investigated. The effect of surgical deletion of parts on survival and regeneration was determined. In isolated sections of the oral complex, the disk including the nerve ring and calcareous ring was able to survive and regenerate. Even small fractions of this disk began regeneration. Regeneration capacity and survival capacity were tested independently by deletion of parts from half animals. Regardless of the deletion, normal morphallactic posteriad regeneration occurred in animals surviving beyond five days. This was true even when the entire oral complex was deleted. Thus, no part of the oral complex is necessary for regeneration of posterior parts.

Survival of a high percentage of the population was restricted to populations lacking a coelomic cavity (i. e., isolated pieces of the oral complex), or to those with a complete water vascular system. Simple section of the connection between the tentacular ampullae and the water ring leads to death in all animals with a coelomic cavity. A role for these parts in oxygenation of the coelomic fluid is suggested.

Finally, the ability of the organism to regenerate deleted parts was tested. Missing parts posterior to the oral complex can be regenerated. In addition, lateral parts of the oral complex and the tentacles can be regenerated. Regeneration away from the disk containing the calcareous ring and the nerve ring always occurs. Regeneration towards this disk never occurs.
The Hi agglutinogen of chickens: Basis for cell transformations
Authors: Scheinberg S. L.
Published: June 2005

Investigations on the Hi substance, a red cell agglutinogen of chickens were continued. The objective was to understand the nature of the cyclic changes which red cells possessing the Hi substance undergo. It was postulated that in Hi birds the erythrocyte precursor cells possess the Hi agglutinogen; that binding of serum proteins to estrogen occurs in laying hens and in birds injected with estrogen and that the attachment of serum protein to the Hi sites of young cells results in non‐reactive cells. Support for the hypothesis was obtained in a variety of tests. Red cells were found to be reactive with anti‐chicken IgG in agglutination tests and red cells of estrogen injected birds were less reactive than non‐injected birds. Young cells from a non‐injected male were more reactive with Pisum arvense than the total red cell population with the converse the case with anti‐IgG. It was also possible to inhibit the agglutinability of embryonic cells for Pisum arvense by coating such cells with plasma from the embryo's male parent. This coating can be inhibited by molecules that specifically inhibit the in vitro agglutination reaction with Pisum arvense, i.e., D‐melezitose. The attachment of IgG therefore specific for Hi sites.
Expression of the paternal genes for glutamate‐oxaloacetate transaminase (GOT) during embryogenesis in Xenopus laevis
Authors: Johnson Kurt E. , Chapman Verne M.
Published: June 2005

Genetic differences in soluble glutamate‐oxaloacetate transaminase (GOT) electrophoretic mobility have been used to determine the time of expression of paternal genes in Xenopus laevis embryos. Maternal isozymes in unfertilized eggs persist through the first two days of development. Paternal‐type bands appear at three days of development when embryos are Stage 37 (gill circulation). The time of expression of paternal GOT genes appears to occur at the same stage as in R. pipiens ♀ × R. palustris ♂ hybrids. These results are discussed in terms of the genomic control of early amphibian development.
Regeneration of locally irradiated salamander limbs following superficial skin incisions or nerve transection
Authors: Conn H. , Wessels S. , Wallace H.
Published: June 2005

It is well known that prior local irradiation inhibits the ability of larval salamanders to regenerate an amputated limb, and that implantation of various non‐irradiated tissues at the site of amputation restores this ability. Neither wounds in the irradiated region, nor wounds in the non‐irradiated shoulder, promote regeneration. A superficial slit in the skin stretching from non‐irradiated tissue to the irradiated site of amputation, however, restores the ability to regenerate. It is presumed that non‐irradiated cells migrate down the slit during wound‐healing and are thus present at the site of amputation and stimulate regeneration.

Transection of the nerve roots following local irradiation of the limb permits a regrowth of non‐irradiated axons into the irradiated limb. Such limbs recover both sensory and motor co‐ordination and the ability to regenerate. Non‐irradiated sections of nervous tracts (axons, Schwann cells and connective tissue sheaths) also promote regeneration when transplanted into irradiated limbs.

Since a nerve supply is almost always needed for limb regeneration, yet an irradiated nerve is sufficient for this purpose, no special sensitivity of nerves to x‐rays is implied by these experiments. The normal function, regrowth and trophic effects of axons appear to be unimpaired by exposing the entire neuron to doses of irradiation that inhibit limb regeneration.
Effects of gonadotropins and testosterone on the testes of prepubertal mice
Authors: Hitzeman Sister Jean Walter
Published: June 2005

Pituitary follicle‐stimulating hormone FSH supports the synthesis of testicular proteins prior to the onset of spermatid formation. Supplementary FSH enhances the activities of certain enzymes that generate reduced nicotinamide adenine dinucleotide phosphate (NADPH) and induces the division and differentiation of Leydig cell precursors. In addition, exogenous FSH counteracts the effects of continued treatment with testosterone on Leydig cells up to the third week postpartum and offsets the effects of the steroid on the weights of the prepubertal testis and seminal vesicles. In its antagonism of testosterone and its activation of glucose‐6‐phosphate dehydrogenase (G6PDH), FSH clearly differs from the interstitial‐cell‐stimulating hormone ICSH during the first wave of spermatogenesis in the mouse testis.
An analysis of the formation of ciliary primordia in the hypotrichous ciliate Urostyla weissei. II. Results from ultraviolet microbeam irradiation
Authors: Jerka‐Dziadosz Maria
Published: June 2005

Localized UV irradiation and protargol staining were used to study the development of cirral primordia during regeneration of the promers of Urostyla weissei. The aim was to analyze the role of preexisting structures in the formation of primordia.

The preexisting frontal cirri were removed by UV irradiation and formation of a new ciliary streaks was observed. When one of the disaggregating old cirri was removed the rest dedifferentiated normally and in the precise place where the irradiated cirrus had been several new kinetosomes appeared. Thus, the formation of these kinetosomes does not depend on the presence of preexisting ciliature at this site. The results provide further support for the hypothesis of integrated cortical activation combined with localized competence of formation sites.
Fine structure of the neural fat‐body sheath in the stick insect and its physiological significance
Authors: Huddart Henry
Published: June 2005

The interganglionic connectives of the stick insect ventral nerve cord are surrounded by a fat‐body sheath, additional to the glial layer, perineurium and neural lamella found in other insects. The sheath is composed of a series of single‐cell lobes, bound together by an extracellular lamella of collagen fibrils in a mucopolysaccharide matrix. Each sheath cell contains a storage area of glycogen granules, fat‐droplets and protein secretory granules, and a secretory area with abundant granular endoplasmic reticulum which produces the protein granules. The fat‐body sheath appears to actively regulate the electrolytes in the extraneural space within the sheath. The low sodium and high potassium of the haemolymph, which are unfavourable for normal central nervous system activity, appear to be regulated in the extraneural space to surround the nerve elements with a fluid more favourable for impulse conduction. The presence of the fat‐body sheath is almost certainly related to the unusual haemolymph composition in the stick insect, and similar diffusion barriers may well be present in other herbivorous insects of unusual haemolymph composition.
Reciprocal fertilization between the ferret and short‐tailed weasel with special reference to the development of ferret eggs fertilized by weasel sperm
Authors: Wu J. T. , Chang M. C.
Published: June 2005

Epididymal spermatozoa of short‐tailed weasels (Mustela erminea) were inseminated into the uterine horns of ferrets (M. furd) and vice versa. When examined 46 hours to six days after injection of HCG for the induction of ovulation, 67 of 86 ferret eggs (78 %) were fertilized by weasel spermatozoa as shown by the enlargement of sperm head, formation of pronuclei, and the cleavage of eggs. The number of chromosomes in a few mitotic plates of cleaving eggs was much smaller than the diploid number of both the ferret and weasel. Implantation of ferret eggs fertilized by weasel spermatozoa occurred on days 13–14, similar to the ferret but different from the long delayed implantation in the weasel. On days 24–28 only seven of 39 implantation sites (18%) from six ferrets contained hybrid fetuses of varying sizes, which were much smaller than ferret fetuses. A nearly full‐grown hybrid fetus was obtained on day 42 from one of three ferrets, but no young was born from another three animals kept to day 54. Weasel eggs could be fertilized by ferret spermatozoa but their developmental potential was not determined.
Fertilization of frog body cavity eggs enhanced by treatments affecting the vitelline coat
Authors: Elinson Richard P.
Published: June 2005

Amphibian eggs which have not been coated with jelly in the oviduct (body cavity eggs) are not fertilized when placed with sperm. When body cavity eggs of the frog Rana pipiens were briefly treated with trypsin and then inseminated in a water‐extract of the jelly (egg‐water), however, high frequencies of fertilization were obtained. A low frequency of fertilization of trypsin treated eggs but not of untreated eggs was obtained even in the absence of egg‐water. Similar results were obtained when eggs were pretreated with cyanide. Both trypsin and cyanide produced a visible weakening of the vitelline coat, the extracellular coat surrounding a body cavity egg. When a rip was made in the vitelline coat and the eggs were inseminated in egg‐water, fertilization occurred. The success of these three pretreatments in producing fertilization of frog body cavity eggs strongly suggests that the vitelline coat is a block to fertilization of these eggs.

The fertilized body cavity eggs exhibited considerable difficulty in completing
gastrulation. Those that began neurulation often had abnormalities of the pos
terior end. However, tadpoles that appeared to be normal could be raised from
fertilized body cavity eggs.
Localization of phosphatase activity on the membranes of the mammalian sperm head
Authors: Gordon Mildred
Published: June 2005

Epididymal and ejaculated rabbit sperm and ejaculated human sperm were incubated at pH 7.0 and pH 9.0 to test for phosphatase activity. With the substrates tested, ATP, ADP, AMP, ITP, p‐nitro‐phenyl phosphate, and glucose‐6‐phosphate, enzymes capable of dephosphorylating ATP at pH 7.0 were localized on the periacrosomal portion of the plasmalemma in epididymal but not in ejaculated sperm. The enzyme was active without divalent cations. In both epididymal and ejaculated sperm the outer membrane of the acrosome was reactive at pH 9.0 with ATP and Ca++. These strikingly different properties of the phosphatases on the plasmalemma and acrosome membrane indicate that the enzymes may be adapted to respond to particular environmental stimuli and function in tandem to bring about the capacitated state and acrosome reaction. The fact that the plasmalemmal enzyme could not be elicited in ejaculated sperm suggests that seminal plasma may contain an inhibitor for this enzyme which is removed in utero. Calcium ions are necessary for activation of acrosomal proteinases. During capacitation in the uterus, the plasmalemmal psphatase may move exogenous Ca++ into the cytosol surrounding the acrosome, thus stimulating the acrosomal membrane enzyme which may then transport Ca++ into the acrosomal vesicle. Calcium ions may also bind the plasma lemma to the outer acrosome membrane and so prepare the membranes for the acrosome reaction.
The distribution of ammonia‐generating enzymes along the intestine of the earthworm, Lumbricus terrestris L
Authors: Tillinghast Edward K. , MacDonnell Paul C.
Published: June 2005

The linear distribution of ammonia‐generating enzymes (L‐serine dehydratase and 5′‐AMP deaminase) along the gut of Lumbricus has been examined using that of the digestive enzymes as a frame of reference.

This study confirms the observations of earlier workers indicating a high activity of digestive enzymes in the anterior region of the gut with declining activity toward the posterior.

5′‐AMP deaminase has a distribution paralleling that of the digestive enzymes. In contrast, L‐serine dehydratase is exclusively confined to the hindgut. It appears, therefore, that two potential centers for ammonia production exist in this species.
Chemical modification of cell type determination in Amphibian embryos
Authors: McDonald Ruth I.
Published: June 2005

The polyanion, polyethylene sulfonate, and the polycation, protamine sulfate, alter the epidermal differentiation of ventral ectoderm in the axolotl, Ambystoma mexicanum. Polyethylene sulfonate reverts stage 121/2 ventral ectoderm, determined to become epidermis, to ectoderm competent for neuralization, while protamine sulfate reduces the neuralization of stages 10½–11 ectoderm. Polyethylene sulfonate also decreases the basic protein staining in the nuclei of stage 121/2 ventral ectoderm and the amount of intense staining heterochromatic DNA in stages 12, 121/2, and 13 ectoderm. Protamine sulfate, in contrast, increases the basic protein staining and the amount of heterochromatic DNA in stages 11 to 14 ventral ectoderm. In addition, polyethylene sulfonate also causes a doubling of the mitotio index of stage 121/2 ventral ectoderm. On the basis of these results, the theory is proposed that the reversal in determination of stage 121/2 ventral ectoderm following polyethylene sulfonate involves decreased histone‐DNA binding and increased DNA replication.
The antigenic pattern of the developing brain of the zebrafish, Brachydanio rerio. II. Brain specific antigens
Authors: Laale Hans , Singh Lakheram
Published: June 2005

Organ and tissue supernates of the zebrafish, Brachydanio rerio, were analysed by immunoelectrophoresis with unabsorbed and absorbed rabbit antiserum to adult zebrafish brain. Four brain specific antigens were detected.
Microtubules, microfilaments, and pigment movement in the chromatophores of Palaemonetes vulgaris (Crustacea)
Authors: Robison W. Gerald , Charlton Jeannette S.
Published: June 2005

The glass shrimp, Palaemonetes vulgaris changes to match the color of its background by a rapid, so‐called physiological color change and a much slower, morphological color change. Apparently both are controlled by hormones, but the rapid color change is mediated by translocations of pigments within stellate cells called chromatophores, whereas the slow color change is effected by selective increases in certain types of chromatophore pigments. The large, dark chromatophores of the ovary were isolated intact and shown to be polychromatic (perhaps four pigments) by correlating light and electron microscopy. Incubated chromatophores supplied with crude extracts of certain neurosecretory tissues exhibit centripetal movement of pigment equivalent to that observed in vivo when a prawn is transferred from a dark‐colored background to a light‐colored background. Centripetal translocation of pigment is not inhibited in the chromatophores by preincubation in 10−3 M colchicine or vinblastine sulfate even though the vinblastine treatment elicits production of crystalline complexes of microtubular protein in place of the normal bundles of microtubules. Cytochalasin B (10 μg/ml) blocks pigment migration reversibly, but does not disrupt microfilaments or other ultrastructural elements. Apparently, normal pigment aggregation depends on some function which is reversibly sensitive to cytochalasin B, and not on the impressive system of microtubules in these cells.
Gas exchange in a cerianthid
Authors: Sassaman Clay , Mangum Charlotte P.
Published: June 2005

Analysis of the determinants of oxygen exchange in Ceriantheopsis americanus, a tubicolous anthozoan, indicates that in the natural habitat the site of oxygen entry is restricted to the tentacular crown. Predicted rates of oxygen diffusion solely across the marginal tentacles are sufficient to account for observed uptake rates in intact animals. The anatomical restriction of the site of exchange is, in part, a result of the absence of active irrigation of the tube. This pattern of gas exchange is more like that in epifaunal anemones than in a previously studied burrowing anemone.

Gradual decline in ambient pO2 leads to a gradual decrease in oxygen consumption rate. Although the partial pressure differential across the exchange surface drops with declining ambient pO2, this decrease is not sufficient in itself to explain the relationship between oxygen consumption rate and ambient pO2. We suggest that differential oxygen sensitivities of the epidermis and gastrodermis and changes in surface area and diffusion distance during expsure to lowered pO2 may modify the oxygen consumption response.
The effects of an elevated temperature, colchicine, and vinblastine on axonal microtubules of the crayfish (Procambarus clarkii)
Authors: Hinkley Robert E. , Samson Frederick E.
Published: June 2005

Microtubules of isolated crayfish ventral nerve cords rapidly dissociate at 40°C and upon reincubation at ambient temperatures part of the microtubule population transiently reforms. Colchicine had little effect on the structure or number of intact microtubules of unwarmed nerve connectives, but vinblastine caused a decrease in microtubular numbers and led to the formation of typical paracrystalline arrays. After warming, both colchicine and vinblastine treatment prevented microtubule reassembly, presumably by interacting with the heat‐induced microtubular dissociation products, and led to the formation of axoplasmic inclusions. The inclusions seen in vinblastine‐treated prewarmed connectives were identical to the paracrystalline arrays produced in unwarmed preparations but the inclusions seen following colchicine treatment of warmed connectives have a unique appearance and are ultrastructurally distinct from vinblastine‐induced arrays.
Effect of a highly purified growth hormone on limb regeneration in the hypophysectomized newt, Notophthalmus viridescens
Authors: Bromley Stephen C , Thornton Charles S
Published: June 2005

Preparations of ungulate growth hormone that have been used thus far to establish the role of that compound in supporting limb regeneration in hypophysectomized newts have contained significant prolactin contamination. Prolactin when present with thyroxin has been shown to be effective at low doses in supporting limb regeneration in these animals. The present communication demonstrates that a highly purified preparation of bovine growth hormone is able to support limb regeneration in hypophysectomized newts at essentially normal levels. Previous results indicating that prolactin and thyroxin in combination restore the regenerative response are corroborated. Thyroxin alone, or prolactin alone, gave a much reduced response. Purified growth hormone, while effective alone, is apparently antagonized by the presence of thyroxin.
Isocitrate lyase activity in the regenerating forelimb of the adult newt
Authors: Jasch Laura G. , Schmidt Anthony J.
Published: June 2005

Regenerating and non‐regenerating limb tissues from the adult newt, Diemictylus viridescens, were assayed for isocitrate lyase activity. The enzyme assays were performed by micromodifications of existing procedures. In general, the whole homogenate, or a soluble fraction of the homogenate, was incubated with the substrate isocitrate. Isocitrate is cleaved by isocitrate lyase to glyoxylate and succinate. At the termination of the reaction, the 2,4‐dinitrophenylhydrazone derivative of glyoxylate was produced, extracted and quantitated spectrophotometrically. Isocitrate lyase activity was localized to bulb and two‐digit regenerates. The reaction product, glyoxylate (a monocarboxylic keto acid), was of special interest due to its role as a potent in vitro metabolic inhibitor. Therefore, the endogenous level of monocarboxylic keto acids, and the ability of regenerating tissue to produce and accumulate monocarboxylic keto acids, were investigated. Whole homogenates of regenerating tissue always contained more monocarboxylic keto acids than intact forearm or stump tissue. Also, after 30 minutes incubation with buffer alone, only regenerating tissue produced and accumulated additional monocarboxylic keto acids. In regenerating tissue, the isocitrate lyase reaction may be utilized in the metabolism of lipid. Since regenerating tissue can produce and accumulate monocarboxylic keto acids in vitro, glyoxylate produced by the isocitrate lyase reaction may accumulate in vivo and participate in metabolic regulation.
Helical polysomes in muscles of regenerating newt limbs
Authors: Deck J. David
Published: June 2005

During the process of amphibian limb regeneration muscle fibers injured by the amputation lose their myofibrils and sarcoplasmic systems of membrane. Fragmentation of many of these dedifferentiated fibers to produce regeneration blastema cells has been reported numerous times by other investigators. The present work utilizing the electron microscope calls attention to dedifferentiated fibers that contain numerous helical polyribosomes and disorganized myofilaments. A number of polysome‐filled cells can be found beside mature muscle fibers as if in the process of fusing. In embryonic muscle, individual myoblasts containing helical polysomes fuse continually to form multinucleated fibers. The presence of the helical polysomes and myofilaments in sparsely fibrillar muscle elements of the regenerating limb, together with other features, is taken as evidence that the muscle elements are stages of regenerating fibers. These regenerating fibers can be found several days before the blastema becomes visible at the limb tip and are a normal part of the overall regeneration process. Indeed, tissue regenerative events marked by the appearance of helical polysomes become evident so soon after muscle injury/amputation that they imply a continuous but probably subliminal tissue turnover that is unmasked by the injury. According to the degree of injury, either the synthetic or the destructive phase of turnover might be favored, resulting in repair or extensive dedifferentiation of the individual fibers. Whether tissue regeneration or blastema cell formation thereafter occurs seems to be determined in part by the closeness of the fibers to the amputation surface.
In vitro analysis of gene depression in goldfish choroidal melanophores
Authors: Kajishima Takao
Published: June 2005

The common goldfish depigments its larval choroidal melanophores as well as the skin melanophores for about two to three months following hatching. Thereafter it begins to show a characteristic xanthic coloration. This depigmentation is under the control of depigmentation genes Dp1 and Dp2. The larval choroidal melanophores of the common goldfish were cultured in vitro for more than four months without showing any sign of depigmentation. During the same period the skin and choroidal melanophores in the control fish had completely depigmented. The addition of thyroid hormone and ACTH to the culture medium had no effect on depigmentation. The mechanisms of depigmentation in the goldfish are discussed.
Limb development in Diplopodia4: A polydactylous mutation in the chicken
Authors: Maccabe Jeffrey A. , Maccabe Astrida B. , Abbott Ursula K. , McCarrey John R.
Published: June 2005

In a study of the polydactylous mutation of the domestic chicken, diplopodia4, we have found that the genetic lesion affects primarily the mesoderm and only secondarily the ectoderm. The effect of this mutant mesenchyme on overlying ectodermal ridge, either mutant or normal, is to thicken the ridge preaxially, leading to increased outgrowth and preaxial polydactylism. A “zone of polarizing activity” in the normal limb‐bud seems to have a role in the control of its anteroposterior polarity. We have examined diplopodia4 limb‐buds for polarizing activity and found it to be normal in its activity and distribution. These results suggest that the supernumerary outgrowth in the mutant limbs result from increased ridge maintenance activity by the mesoderm without a concomitant increase in the activity or distribution of the polarizing zone.
On the mode of action of hydroxyproline in Drosophila development
Authors: Rapport E. W.
Published: June 2005

Hydroxyproline (OHP) fed to Drosophila larvae is known to impair the ability of pupae to evert cephalic structures and leg and wing discs. In order to gain insight into the metabolic basis of OHP action we have investigated the effects of combined feeding of OHP and several compounds. Proline, glucosamine HCl, and N‐acetyl glucosamine considerably reduced the extent of morphological defects of OHP, while alanine and sodium glutamate were less effective. Glutamine and glutathione did not reduce the effects of OHP. The results are consistent with the hypothesis that OHP may indirectly interfere with cuticle synthesis.
Epilation of growing hair follicles
Authors: Johnson Elizabeth
Published: June 2005

Epilated growing follicles continue to grow. They produce a length of hair which is shorter than that produced by intact follicles over the same period of time, because they grow for a shorter time and at a lower rate.
A new behavioral bioassay for an analysis of sexual attraction and pheromones in insects
Authors: Nissani Moti
Published: June 2005

Drosophila melanogaster gynandromorphs were introduced into a mating chamber containing two wild type males. From the differential courtship responses of these males it could be concluded that the only important factor which enables a male to distinguish between conspecific males and females and to direct persistent courtship only toward females is tissue composition of females. This fact is interpreted in terms of a female‐specific sex pheromone. Most of this pheromone is produced by cells whose precursors on the blastoderm surface are very close to, or identical with, the blastoderm precursors of the tergites. Some of this pheromone is probably produced by cells whose precursors are very close to, or identical with, the precursors of the sternites and thorax.
Glycoprotein and protein antifreezes in two Alaskan fishes
Authors: Raymond J. A. , Lin Y. , DeVries A. L.
Published: June 2005

Two macromolecular freezing point depressants have been isolated from the serums of two species of Alaskan fishes. A common property of the four antifreezes thus far isolated is a high alanine content which suggests that the mechanism of these antifreezes may be related to a repeating tripeptide unit.
Comparative physiology and the challenge of design
Authors: Barrington E. J. W.
Published: June 2005

Analysis of the complexity of biological organization commonly takes us through an initial and necessary stage of over‐simplification towards the ultimate goal of an appreciation of the subtle intricacy of nature.

One example of this is that recent advances in studies of the phosphagens Have failed to confirm earlier hopes that the distribution of these substances could be used to confirm phylogenetic relationships. It is now suggested that a previously unrecognized factor influencing this distribution may be competing demands for arginine in the development of the testes.

Another illustration is the belief that the presence of iodine in ascidians may provide a clue to the origin of thyroidal biosynthesis. This belief is probably sound, but the presence of abundant iodine in the tunic may well be a false trail. More significant is the presence of much smaller amounts of bound iodine in the endostyle, where its presence is probably correlated with specialized protein metabolism associated with the ciliary feeding mechanism.

A third illustration, discussed in more detail, is provided by recent recognition that the gut is a major component of the vertebrate endocrine system. This lays open attractive fields of research, ranging from problems of molecular and hormonal evolution to aspects of fish farming and the physiology of gut parasites.

The need is thus plain for breadth of perspective in comparative physiological research, and for recognition that the ultimate concern of the biologist is with the life and relationships of the whole organism.
Multienzymic nature of pyruvate kinase during development of Hymenolepis diminuta (Cestoda)
Authors: Carter Clint E. , Fairbairn Donald
Published: June 2005

H. diminuta at different stages of development contained as many as five pyruvate kinase isozymes. Four of these were unusually sensitive to allosteric activation by fructose‐1,6‐P2. One isozyme which occurred only in adults or near‐adults was insensitive but had a relatively low Km. All were inhibited by ATP and Ca2+, none by alanine, and the pH optimum was unaffected by fructose‐1,6‐P2. The five isozymes were present in gravid or reproductively active proglottids. Two of them occurred after eight days growth in the rat intestine, and three after four days. These three were also present in the immature, anterior proglottids of adult parasites. Hexacanth larvae from gravid proglottids, as well as cysticercoids developing from these larvae in Tenebrio molitor, possessed only two isozymes. It was inferred from information on tissue concentrations of ADP, ATP, phosphoenolpyruvate (PEP), and on K0.5s and Km that competition between pyruvate kinase and PEP carboxykinase is probably controlled by fructose‐1,6‐P2 concentrations. Since H. diminuta is an obligatory fermenter in which gluconeogenesis is minimal, the probable function of its L‐type pyruvate kinases is to control the specific composition of lactic, acetic and succinic acid mixtures that are excreted at different stages of development.
Effects of wheat germ agglutinin on fertilization of mouse ova in vivo and in vitro
Authors: Parkening Terry A. , Chang M. C.
Published: June 2005

Mouse ova with or without follicular cells (denuded) were treated with wheat germ agglutinin (WGA) in concentrations ranging from 5–500 μg/ml and fertilized in vitro. Ova subjected to concentrations greater than 10 μg/ml WGA were incapable of fertilization in vitro, although sperm were observed adhering to the zona pellucida after treatment in concentrations as high as 500 μg/ml WGA. At concentrations of 50 μg/ml or higher, WGA adversely affected the shape of the vitellus. Of various saccharides employed to block the effects of WGA D‐glucose was the most effective.

Injections of 0.03 ml of 100 μg/ml or 500 μg/ml WGA into the ovarian bursa two to three hours before the expected time of ovulation had little or no effect on fertilization in vivo.
Frog lysozyme. I. Its identification, occurrence as isozymes, and quantitative distribution in tissues of the leopard frog, Rana pipiens,
Authors: Ostrovsky David S. , Snyder John A. , Iwata Takuzo , Izaka Ken‐Ichi , Maglott Donna S. , Nace George W.
Published: June 2005

In the course of examining the etiology of the Lucké renal adenocarcinoma of the frog, Rana pipiens, it was found that organs of the normal adult contain bacteriolytic enzymes. These enzymes all satisfied the six criteria for the identification of lysozymes and at least eight forms were separable by polyacrylamide gel electrophoresis. Their qualitative and quantitative distribution was organ‐specific. All eight isozymes were found in normal kidney, while liver and spleen contained seven forms; skin, six; ovarian egg, five; and serum, two.

In quantitative assays using a radial diffusion test, spleen had the greatest lysozyme concentration, followed in descending order by kidney, liver, skin, and ovary. Serum contained very low amounts. In terms of enzyme activity per animal, ovary was the highest ranking organ. As such a large number of lysozyme isozymes has not been reported in any other organism, their origins and functions are considered in the context of their presence in an ectotherm.
Polarizing activity in the developing limb of the Syrian hamster
Authors: Maccabe Jeffrey A. , Parker Brenda W.
Published: June 2005

The transplantation of small pieces of tissue from the limb buds of 9 1/2 – 10 day hamster embryos to the wing bud of the chick results in the induction of supernumerary wing structures. The anteroposterior polarity of these induced structures is under the control of the transplanted hamster tissue. The developing hamster limb thus has limb polarizing activity similar to that found in avian species and, as in the chick, the activity is found primarily in the posterior region of the limb bud.
Mouse sperm genotype and the rate of egg penetration in vitro
Authors: Fraser Lynn R. , Drury Linda M.
Published: June 2005

(C57BL/10 × CBA)F1 mouse eggs were incubated in vitro with either F1 or outbred TO sperm for 15 minutes‐6 hours. Upon removal from the sperm suspensions some eggs were treated with pronase to remove zonae and then cultured, while the remainder were simply cultured to allow a comparison of the fertilization rates in the two groups. Although a brief incubation was sufficient for a high rate of fertilization when the zonae remained intact, results from the zona‐free eggs indicated that penetration, i.e., sperm fusion with the vitellus, had not been achieved in all eggs during the shorter incubations. Results from the latter groups of eggs indicated that a 1 hour incubation with TO sperm and a 2 hour incubation with F1 sperm were needed to obtain a mean fertilization rate of 50%. Fertilization was complete within 1.5 hours using TO sperm and 2.5 hours using F1 sperm, thus indicating that under similar environmental conditions sperm genotype can significantly affect the rate of penetration.
Humoral immune responses in Rana catesbiana frogs and tadpoles
Authors: Pross Susan H. , Rowlands David T.
Published: June 2005

Rana catesbiana adult frogs and tadples were immunized with the bacteriophage F2, ϕX‐174, and T4 and the haptens 2,4 dinitrophenyl (DNP) and fluorescein (FTC). The haptens were conjugated with bovine serum albumin (BSA), bovine gamma globulin (BGG), or horseshoe crab hemocyanin (Hycn). Sera were obtained from immunized animals at intervals up to six months after immunization. The antibody activities were measured by bacteriophage neutralization techniques. Sucrose density gradients were used to separate the antibody classes.

Both adults and tadpoles responded to each of the antigens tested. High molecular weight antibodies were predominant in both groups of animals. Low molecular weight antibody activity was not found in adults until nine weeks post immunization but, thereafter, this fraction increased throughout the immune response. Low molecular weight antibodies could also be identified in serum of tadpoles, but only under certain conditions.
Failure of XX cells containing the sex reversed gene to produce gametes in allophenic mice
Authors: Gordon Jon
Published: June 2005

Allophenic mice have been produced by combining embryos from normal albino mice with embryos of normally pigmented mice carrying the autosomal dominant for sex reversed (Sxr) in order to determine the ability of XXSxr cells to differentiated either into sperm or eggs. Sixteen male and six female allophenes have thus far produced more than 1,200 offspring, none of which arose from an XXSxr primordial germ cell. Two allophenic mice were sterile hermaphrodites, and 13 others have yet to be tested. These results indicate that an XX cell is incapable of spermatogenesis even when supplied with the male determining Sxr gene, and that this gene also prevents XX cells from undergoing oogenesis. The latter result contrasts with a previous report of a functional sex reversed oocyte in the mouse.
Effect of streptomycin on the structure and function of the photoreceptor apparatus of Euglena gracilis
Authors: Ferrara Romano , Banchetti Rosalba
Published: June 2005

The progressive modification of the photoreceptor apparatus, induced by addition of streptomycin (SM) to cultures of dark‐bleached Euglena, is correlated with the change of the photomotor response. One of the effects of drugtreatment is the reduction of carotenoid synthesis; the total carotenoid content decreases from 0.20 to 0.01 pg/cell after seven weeks of treatment. The parallel progressive reduction of the stigma vesicles and their carotenoid content is observed by electron microscopy. Micrographs and microscopic fluorescence observations do not indicate alterations of the paraflagellar body (PFB). During the SM‐treatment the initial positive phototactic response decreases until it disappears after five weeks.

The loss of the absorbing properties of the stigma prevents the cell from orienting itself towards the light. The probability that the cell orients seems to depend on the light modulation amplitude and the light/dark ratio on the PFB due to the shading device. After seven weeks of SM‐treatment we observe a cell movement away from the illuminated zone. The mechanism of this escape is discussed.
Three dimensional structure of the endochorion in wild type Drosophila melanogaster
Authors: Margaritis Lukas H. , Petri William H. , Kafatos Fotis C.
Published: June 2005

The endochorion of the Drosophila melanogaster eggshell has been isolated and its structure examined by transmission and scanning electron microscopy. In the main shell the thin inner endochorion (floor) shows small pits or pores and characteristic fenestrae crossed by irregular strands; vertical columns surrounded by air spaces separate this layer from the thick outer endochorion (roof) which is covered by a regular, external reticulum of thin fibers. The endochorion of the respiratory horns has sharply divided dorsal and ventral surfaces, with characteristic structures somewhat reminiscent of the floor and the external reticulum of the roof, respectively.
Electrophysiological responses of chemosensitive sensilla in the wolf spider
Authors: Drewes Charles D. , Bernard Rudy A.
Published: June 2005

Electrophysiological recordings from single, open‐pored sensilla on the pedipalps of intact wolf spiders confirm the presence of numerous chemosensory neural units in the sensilla. The presence of one or two mechanosensory neurons in these sensilla is also confirmed.
The nature and development of sex attractant specificity in cockroaches of the genus Periplaneta. III. Normal intra‐ and interspecific behavioral responses and responses of insects with juvenile hormone‐altered antennae
Authors: Schafer Rollie
Published: June 2005

Male cockroaches of the species Periplaneta americana rely on a female‐produced airborne pheromone to initiate courting behavior. The male responds to the presence of the pheromone with rapid, oriented locomotion. Contact with the female (or other males or larvae) elicits wing‐raising and other responses characteristic of male courtship behavior. Males of other species within the genus Periplaneta also respond to a female‐produced pheromone, but with less intensity than P. americana. Cross‐species testing shows that P. brunnea males respond to the Periplaneta pheromone with the same intensity elicited by the P. brunnea pheromone. A second reaction group containing P. australasiae, P. fuliginosa, and P. japonica also responds to the P. americana pheromone and their conspecific pheromones, but with a low intensity characteristic of these species. Alteration of the antennal morphology of P. americana males can be experimentally induced by manipulating the level of juvenile hormone during development. Males with a full adult complement of olfactory receptors all respond behaviorally to the pheromone. Adult males with larval antennae produced by bilateral treatment with exogenous juvenile hormone‐mimic do not respond to the pheromone, although they are completely adult in other respects.
Activation of hamster eggs by pricking
Authors: Uehara T. , Yanagimachi R.
Published: June 2005

When mature unfertilized eggs of the golden hamster were pricked with a glass needle, nearly 80% of them were activated. The diameter of needle was of critical importance for the successful induction of activation. It appeared that extracellular calcium was not necessary for the establishment (reception) of stimulation by pricking but was necessary for later phases of activation. The possible mechanisms by which pricking with a needle triggers the activation of the egg were compared with the mechanisms by which divalent ionophore induces activation.
Kinetics of sperm penetration into and the zona reaction of mouse ova inseminated in vitro
Authors: Wolf D. P. , Hamada M. , Inoue M.
Published: June 2005

The kinetics of capacitated epididymal sperm penetration into cumulus‐intact and completely cumulus‐free mouse ova were studied. Penetration was complete within two hours of insemination in cumulus‐intact ova incubated with 2 × 105 sperm/ml, as evidenced by the attainment of constant values for the mean number of sperm/penetrated ovum. A reduction in sperm viability was not a factor in the cessation of zonae penetration, since high penetration levels were obtained when fresh ova were added to 3‐hour inseminations containing “aged” sperm. With completely cumulus‐free ova, capacitated sperm penetration was initiated between one and two hours post‐insemination, and penetration levels increased over the entire 6‐hour incubation period. Final penetration levels for cumulus‐free ova were generally lower than for their intact counterparts. A constant value for the mean number of sperm/penetrated ovum was obtained after three hours of sperm exposure, indicating that the cumulus‐free ovum also underwent a zona reaction. Similar results were observed when sperm were capacitated in the presence or absence of cumulus and/or epididymal components, suggesting that inadequate capacitation was not the causative agent in the altered penetration of cumulus‐free ova. These results indicate that a zona reaction occurs in both ovum types, although in many cases only after multiple sperm penetration has occurred. In addition, evidence was obtained for a cumulus‐dependent enhancement in the rate of sperm penetration which could not be related to a cumulus involvement in sperm capacitation.
Variations in macromolecular antifreeze levels in larvae of the darkling beetle, Meracantha contracta
Authors: Duman John G.
Published: June 2005

Overwintering larvae of the darkling beetle, Meracantha contracta, produce a macromolecular antifreeze that is similar in activity to the glycoproteinaceous and proteinaceous antifreezes found in some cold‐water, marine teleost fishes. The antifreeze is not present in the hemolymph of the Meracantha larvae in summer, but its production begins by late September in the wild population. The antifreeze reaches a maximum concentration in February, decreases slowly through spring, and disappears by early June. The supercooling points of the larvae are lowest in February, when the antifreeze levels are highest, and increase as the antifreeze concentrations in the hemolymph decrease in the spring. Larvae collected in mid‐February and warm‐acclimated lost the antifreeze within 12 days. Larvae collected in early September and cold‐acclimated required nearly two months to produce concentrations of antifreeze comparable to those of overwintering larvae. Temperature seems to be the major environmental factor responsible for the control of antifreeze levels in Meracantha; however, other environmental factors may also be involved.
Indirect immunofluorescent identification of 19S immunoglobulin‐containing cells in the intestinal mucosa of Xenopus laevis
Authors: Michea‐Hamzehpour Mehrbanou
Published: June 2005

The lymphoid structures in the gastrointestinal tract of immunized and non‐immunized, adult Xenopus laevis were studied by light and fluorescent microscopy. Serial sections stained with May‐Grun̈nwald Giemsa showed that lymphoid aggregations and scattered lymphoid cells are present along the whole digestive tract. The aggregations are few and rather small in the oesophagus and stomach, they are particularly voluminous in the duodenum.

An indirect immunofluorescent technique using antisera against Xenopus laevis 19S and 7S immunoglobulins and their heavy polypeptide chains, revealed the presence of immunoglobulin‐containing cells in the duodenal region. The oesophagus and stomach were devoid of these. It has been shown that the immunoglobulins produced in the duodenal lamina propria are formed of both heavy and light polypeptide chains, and that the heavy chains are of the 19S H‐type.
Nuclear decondensation of mammalian spermatozoa: Changes during maturation and in vitro storage
Authors: Beil Richard E. , Graves Charles N.
Published: June 2005

Swelling of the spermatozoan nucleus and decondensation of the chromatin occur soon after penetration of spermatozoa into the egg cytoplasm. This decondensation was duplicated in vitro by incubating pre‐ejaculatory ram, rabbit and bovine spermatozoa and also stored post‐ejaculatory bovine spermatozoa in 1% sodium dodecyl sulfate and 2.0 mM dithiothreitol. Spermatozoa obtained from the testis and epididymal caput, corpus and cauda showed a progressive resistance to nuclear decondensation, while no change was evident in the decondensation time of spermatozoa obtained from the epididymal cauda, vas deferens and ejaculated semen. There was also a significant increase in decondensation time after the spermatozoa had been stored in vitro at 25°C. This increased resistance to nuclear decondensation in the in vitro stored spermatozoa, reflecting an increase in cross‐linking within the spermatozoan histones by formation of disulfide bonds, may account for part of the increased embryonic mortality observed when spermatozoa are stored in vitro prior to insemination.
Low NA+ concentration: A factor contributing to diminished uptake and incorporation of amino acids by diapausing mouse blastocysts?
Authors: Van Winkle Lon J.
Published: June 2005

Uptake and incorporation of 14C amino acids by normal and diapausing blastocysts was found to be Na+ dependent with one exception. Delayed embryos preincubated 25 h in medium containing 124 mM Na+ had labeling characteristics independent of the Na+ concentration present during labeling. Since diapausing embryos preincubated 25 h in low Na+ medium (55 mM) retained their Na+ dependent labeling characteristics, delayed blastocysts may be in a low Na+ environment in situ. Low Na+ may explain why delayed blastocysts are unable to utilize radioactive methionine in vivo (Weitlauf and Greenwald, '68).