bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of divalent cations in activation of the sea urchin egg. I. Effect of fertilization on divalent cation content
Authors: Azarnia Roobik , Chambers Edward L.
Published: June 2005

The Ca and Mg content of unfertilized sea urchin eggs (3 and 21 μmole/ml eggs) remains remarkably constant over periods of hours, even when the eggs are suspended in Ca‐ or Mg‐free sea water. After fertilization the Ca content of eggs in regular sea water increases sharply by about 20%, followed by a decrease to the unfertilized level by 40 minutes. However, if the fertilized eggs are washed three minutes in Ca‐free sea water a sharp decrease in the Ca content occurs amounting to 30% of the total in the first 40 minutes, with little change thereafter. Suspension of the eggs in Ca‐free sea water results in an even greater loss of Ca amounting to about 43% of the total in the same time interval, followed by a continuing slow loss. It is concluded that fertilization initiates the intracellular release of Ca, which is then extruded. For unwashed eggs this change is masked by the simultaneous generation of new extracellular coats with high affinity for Ca.

Changes in the Mg content of fertilized eggs follow the same general pattern except that absorption of this divalent cation to the extracellular coats is minimal.
Ultrastructural characterization of the accessory lobes of Lachi (Hofmann's nuclei) in the nerve cord of the chick. I. Axoglial synapses
Authors: De Gennaro Louis D. , Benzo Camillo A.
Published: June 2005

Light microscopic observations of the accessory lobes of Lachi of one‐day‐old chicks show that this tissue contains abundant amounts of glycogen and consists of cells which are similar in appearance to those of the glycogen body. Ultrastructural studies reported here for the first time confirm the presence of glycogen‐rich cells in the accessory lobes and reveal that these cells are intimately associated with nerve axons. The finding of synaptic complexes and other junctional specializations between nerves and accessory lobe cells suggests that they may have a functional relationship with the nervous system. It is felt that the accessory lobe cells may be neuroglia, possibly of the astrocytic type, which have an innate capacity for glycogen storage. While the functional significance of such glycogen remains obscure, the close morphological association between neurons and the accessory lobe cells enhances the hypothesis put forth by us regarding the glycogen body, namely that neural glycogen is involved in myelin synthesis in the avian nervous system.
Respiratory behaviour of sea‐urchin spermatozoa. II. Sperm‐activating substance obtained from jelly coat of sea‐urchin eggs
Authors: Ohtake Hideki
Published: June 2005

A sperm‐activating substance (SAS) was obtained from the jelly coat of sea‐urchin ova and its chemical properties were investigated in three seaurchin species. The SAS was partially purified from the jelly coat of pseudocentrotus eggs through several steps of purification by procedures consisting of charcoal adsorption, on Sephadex G‐15 columns. The partially purified SAS was found to contain a ninhydrin‐positive material and is inactivated by pronase digestion. The molecular weight of SAS was estimated as about 630 by gel‐filtration through Sephadex G‐25, and the isoelectric‐point of SAS is located at about pH 5.3 by isoelectrofocusing method. The SAS is non‐volatile, alcohol‐soluble, and labile in a diluted alkaline or acid solution. The origin of SAS is discussed.
Chemotactic behavior of mutants of the nematode Caenorhabditis elegans that are defective in their attraction to NaCl
Authors: Dusenbery David B.
Published: June 2005

Wild‐type C. elegans and 16 derivative strains previously selected for defective attraction to NaCl and shown to carry single‐gene mutations were tested for their responses to nine chemical stimuli to which the wild‐type responds. These were the attractants Na+, Cl−, OH−, cyclic AMP, CO2 in borate buffer, and pyridine and the repellents D‐tryptophan, CO2 in phosphate buffer, and acid. All together 563 measurements were performed. Most strains were defective in most responses but responded normally to some chemical stimuli. In a few cases mutant strains avoided a chemical that attracted the wild‐type. Analysis of the patterns of defective responses among these mutants indicates that there are probably at least four different receptors. If results previously reported are included, the minimum number of receptors is increased to six. These mutations appear to have rather discrete effects on behavior.
Electron microscope assessment of fertilization of rabbit ova treated with Concanavalin A and Wheat Germ Agglutinin
Authors: Gordon M. , Dandekar P. V.
Published: June 2005

Zonaless rabbit ova, exposed to Concanavalin A or Wheat Germ Agglutinin, then to uterine capacitated sperm produce pronuclear, 2 and 4 stage embryos that are indistinguishable from controls. Absence of cortical granules indicates that the ova were fertilized and not merely activated. Survival of lectin‐bearing receptors during the period necessary for fertilization was evaluated in ova marked with ferritin‐conjugated lectin.
The relationship between growth, developmental stage and postamputation age of the regeneration blastema of the newt, Notophthalmus viridescens
Authors: Connelly Thomas G.
Published: June 2005

The growth of the regeneration blastema of the newt forelimb has been quantitated and analyzed as a function of postamputation age, developmental stage animal weight, animal length, and cross sectional diameter of the blastemal base in both the anteroposterior and dorsoventral dimensions. Correlation coefficients computed for these variables show that growth of the regenerate in both length and volume is more closely correlated with developmental stage than postamputation age. In addition, the results show a linear relation between the loge (regenerate length) and developmental stage, and between regenerate length and volume. Thus, length can be used to assess growth of the regenerate according to a developmental rather than a chronological time scale. There were no significant correlations between regenerate length or volume and animal length, animal weight or cross sectional dimensions of the blastemal base. These results show that one can use a randomly selected population of animals and study the growth of the regeneration blastema by relating to a developmental time scale through a logarithmic transformation of the linear growth data.
Acetylcholinesterase isozymes in developing mouse tissues
Authors: Henderson Nanine S.
Published: June 2005

Several isozymes of acetylcholinesterase are separated by 10% acrylamide gel electrophoresis of mouse blood, brain, heart, muscle and tongue tissues. Two isozymes migrating near the origin are described which show changes in relative activity during development. The faster of the two bands is proportionately higher in concentration in embryonic tissues and is highly specific for the acetylthiocholine iodide substrate. This isozyme corresponds to the erythrocyte membrane AChE in electrophortic mobility and substrate specificity. The slower of the two bands is predominant in adult tissues and exhibits considerable cross reaction with the butyrylthiocholine iodide substrate. During embryonic and postnatal developmental stages there is a gradual shift from the faster migrating isozyme toward a predominance of the slower migrating isozyme.
The kinetics of rosette‐forming cell response against sharp erythrocytes in the lizard
Authors: Pillai P. Subramonia , Muthukkaruppan Vr.
Published: June 2005

The immune response of the lizard Calotes versicolor to sheep erythrocytes (SRBC) has been studied in terms of the appearance of rosette‐forming cells (RFC) and plaque‐forming cells (PFC). Two distinct RFC peaks were observed in the spleen, one within three days and the other, between six and ten days after immunization with 0.1 ml of 2.5%, 0.25% or 0.025% SRBC. Lower doses of antigen induced greater and quicker first RFC peaks, whereas higher doses stimulated increasing numbers of PFC as well as quicker appearance of second RFC peak. The early increase in RFC response is suggested to be due to “helper” activity and the second peak to the proliferation of precursors of antibody producing cells. Formalinised SRBC induced the formation of the first RFC peak but not the second, thus supporting the above suggestion. The interesting possibilities with regard to the dissociation of various cellular events during the development of antibody response in the lizard immune system are discussed.
Developmental expression and biochemical characterization of catalases and aminopeptidases of Nassarius obsoleta
Authors: Nelson Mark S. , Scandalios John G.
Published: June 2005

Electrophoretic analysis of catalase isozyme patterns of Nassarius obsoleta indicates that these isozymes are products of two separate loci. Five aminopeptidase isozymes have also been detected in N. obsoleta and the data suggest that at least two loci encode these aminopeptidase isozymes. Experiments designed to test for the interconvertibility of the isozymes indicate that the two catalase isozymes and that two of the five aminopeptidase isozymes tested were not conformational artifacts but distinct genetic products. No change in catalase isozyme expression, but considerable quantitative variation in catalase specific activity was noted during early developmental stages of N. obsoleta. Both qualitative and quantitative changes were noted in aminopeptidase expression during early developmental stages. This paper also describes several physicochemical parameters for each of the two enzymes under study.
Physiology and chemistry of cerebrospinal fluid, aqueous humor and endolymph in Squalus acanthias
Authors: Maren Thomas H.
Published: June 2005

By means of the appropriate isotopes injected into the spiny dogfish, Squalus acanthias, the transfer of all major ions into cerebrospinal fluid (CSF), aqueous humor (A) and endolymph (E) was studied. In addition, the effect of raising pCO2 in sea‐water upon HCO concentration of these fluids was measured. In the several types of experiments, acetazolamide or methazolamide was used to inhibit completely carbonic anhydrase. The rates of fluid formation and ion transfer in CSF and A were fairly close, but those for E were far slower. The general pattern of ion transport in the three fluids were the same, Na+ (or Na+ + K+ in E) entry > Cl‐ entry, and the difference was HCO. The greater rate constants for HCO, increase in its entry rate by elevation of pCO2, and inhibition of its appearance by the sulfonamides, show that this is a special case of transport; the ion is formed in secretory cells from gaseous CO2 + OH‐. Secretory cells at sites of formation of all the fluids contain both carbonic anhydrase and Na+‐K+‐ATP‐ase, which subserve HCO formation and Na+ (or K+) transport. Comparison of these results with studies in mammals show that the vertebrate pattern for secretion of these three fluids is well established in the elasmobranch.
Molecular aspects of chloride cell formation in Oncorhynchus. II. Isolation and characterization of gill transfer RNA's during active salt secretion
Authors: Conte F. P.
Published: June 2005

The transfer ribonucleic acids (tRNAs) from gill filaments of coho salmon, Oncorhynchus kisutch, have been isolated and were separated into individual species of acceptor tRNAs by reversed‐phase column chromotography. Crude tRNAs isolated from gill filaments undergoing active salt excretion were acylated with 14C‐amino acids and combined with tRNAs acylated with 3H‐amino acids, but obtained from non‐secreting filaments. The radioactively labeled tRNA mixture was cochromatographed and the results showed significant differences in the elution profiles of tRNAasp and tRNAtyr. These elution profiles may reflect the differentiation of the chloride cell population that is found within the gill epithelium.
Volume regulation of muscle fibres in the killifish, Fundulus heteroclitus
Authors: Schmidt‐Nielsen Bodil
Published: June 2005

Cell volume regulation has been observed in vitro in many tissues. In the killifish it was studied in vivo during transfer from SW to FW and from FW to SW. It was found that the cell water content in acclimated fish varies inversely with the osmolality of the medium. During transfer from SW to FW the plasma osmolality decreased. Cell swelling was prevented through net loss of solutes from the cells. The solutes lost were not potassium or sodium and are presumed to be organic solutes. During transfer from FW to SW the plasma osmolality increased, cell shrinkage occurred and no significant increase in cell solute content could be found during eight hours. During prolonged acclimation cell water content returns to a higher value.
Cytological changes in chloride cells following altered ionic media
Authors: Doyle William L.
Published: June 2005

The rock‐eel, Pholis, and guppy, Lebistes, adapted to fresh or saltwater were exposed to low concentrations of unnatural ions or transport inhibitors including thiocyanate, potassium and ouabain, which caused cytological alterations in the chloride cells of the gills. Some of the other substances used caused generalized damage to intracellular membranes. Highly ordered geometric arrays of the tubular reticulum were produced under certain conditions. The conditions of the experiments suggest that the tubular reticulum plays a role in ionic segregation and that the normal configuration of the reticulum is dependent on the ionic composition of the intracellular milieu.
Physiological adjustments to dilution of the external medium in the lip‐shark Hemiscyllium plagiosum (bennett). II. Branchial, renal and rectal gland function
Authors: Wong T. M. , Chan D. K. O.
Published: June 2005

In undiluted sea water, the lip‐shark Hemiscyllium plagiosum excretes urine high in Mg++ and rectal‐gland fluid with high concentrations of Na+ and Cl−. Urea is excreted largely by the gills (87%), but also by kidney (5%) and rectal gland (6%).

In 50% sea water, the urine flow rate increases while the rate of excretion of Mg++ decreases. The rectal gland continues to secrete a fluid with Na+ and Cl− hypertonic to those of plasma. Branchial loss of urea is diminished as a result of a decline in plasma‐urea concentration so that the clearance rate is unaffected. The U/P ratio for urea increases and the kidney excretes 48.4% of the total urea loss. However, this change in excretion of urea is too small to account for the concomitant decline in body urea content indicating that a reduction in the rate of biosynthesis of urea occurs.
The effects of hydrocortisone and bacterial lipopolysaccharide on the anti‐erythrocyte response in the spleens of adult Triturus viridescens
Authors: Ruben Laurens N. , Gwinnell Esther M.
Published: June 2005

The effects of hydrocortisone (HC) and bacterial lipopolysaccharide (LPS) have been tested separately and in combination, on the antigen‐binding response of splenocytes of the newt, Triturus viridescens immunized with horse erythrocytes (HRBC). The timing of the presentation of each was made relative to when challenge with either low (0.0025%) or high (25%) doses of the immunogen (HRBC) was effected. Our results showed inhibition of both low and high dose responses by HC and additionally suggested that the helpercell population of the newt is HC‐sensitive. LPS given four days prior to antigen challenge initiated the generation of antigen‐binding cells which enhanced the low, but not the high dose response. The use of LPS in conjunction with HC provided suggestive evidence that those LPS stimulated cells which had enhanced the low immunogen dose antigen‐binding cell response were HC‐resistant. Thus LPS may stimulate a non‐helper cell population in the newt which is HC‐resistant. The use of these two immunologic probes has provided supportive evidence on the heterogeneity of the lymphoid population of the newt, Triturus viridescens.
Evidence for the dissimilarity of acrosin and pancreatic trypsin as revealed by a sensitive immunoassay
Authors: Allen Gerald J.
Published: June 2005

Common antigenic determinants between two species of pancreatic trypsin and twelve species of acrosin were studied using a highly sensitive, enzyme‐linked immunoassay. No common antigenic determinants between trypsin and acrosin could be detected.
Analysis of a newly‐isolated temperature sensitive maternal effect mutation of Drosophila melanogaster
Authors: Fausto‐Sterling Anne , Weiner Amy J. , Digan Mary Ellen
Published: June 2005

A mutation located near the tip of the X chromosome in Drosophila melanogaster has been isolated, and its developmental effects described. This mutation (1(1)ts‐1) is temperature sensitive, and at permissive temperature (18°C) develops normally. However, zygotes from females raised or aged at restrictive temperature (28°C) never hatch, regardless of the embryonic genotype. Midgut formation is abnormal in lethal zygotes and dorsal closure is probably incomplete. Temperature shift experiments have shown that the zygotic lethality is governed by a temperature sensitive period in oocytes of stage seven or older. If viable 1(1)ts‐1 embryos are shifted to restrictive temperatures, they develop as far as the pupal stage, but never eclose. The temperature sensitive period for pupal lethality includes the last 2.5 days of pupal development and does not involve a maternal effect.
Cytodifferentiation in the accessory glands of Tenebrio molitor. II. Patterns of leucine incorporation in the tubular glands of post‐ecdysial adult males
Authors: Happ George M. , Yuncker Christine , Huffmire Susan A.
Published: June 2005

The tubular accessory gland of male mealworm beetles undergoes rapid and progressive terminal differentiation in the 8‐day period after ecdysis to the adult. Total protein and RNA content are maximal at five and eight days respectively. Rates of leucine incorporation rise gradually through the first four days and then increase abruptly in the 5‐ to 7‐day interval. SDS‐polyacrylamide gel electrophoresis demonstrates a variety of proteins; two classes with high mobility (Class A and B) appear prominent in homogenates of 5‐ to 8‐day glands.

Double‐label procedures show that as the glands mature, an increasing proportion of the total leucine incorporation passes into Class A and B proteins, until at eight days, Class A and B proteins account for 50% of the total for the gland. The relative incroporation into A vs. B also changes linearly over this interval. The developmental program of the tubular gland includes both a linearly biosynthetic increase in the proportion of differentiation‐specific proteins and an abrupt change in the overall rates of leucine incorporation.
The role of cortical pattern in timing of cell division and morphogenesis in Stentor
Authors: de Terra Noël
Published: June 2005

This paper describes experiments involving reciprocal exchange of the oral apparatus between a large (L) and a small (S) strain of Stentor coeruleus. Mature L‐strain stentors given an S‐strain oral apparatus formed an oral primordium in response to the presence of abnormally small oral structures and mostly divided although a few reorganized instead. Conversely, when S‐strain stentors in early division were given a large L‐strain oral apparatus, they resorbed the developing primordium and returned to interphase. When combined with previous results, these findings provide evidence for the hypothesis that the time of cell division in Stentor is determined by a “critical” ratio between the size of the oral apparatus and the size of the cell body (somatic) cortex. This ratio develops because the somatic cortex grows during interphase and the oral apparatus does not. Cell division in Stentor therefore appears to be initiated by a cortical pattern change resulting from cell surface growth during interphase.
Epidermal‐dermal tissue interactions between mutant and normal embryonic back skin: Site of mutant gene activity determining abnormal feathering is in the epidermis
Authors: Brotman Harris F.
Published: June 2005

The site of the scaleless gene's activity in the development of abnormal feathers was determined by reciprocally recombining epidermis and dermis between normal and scaleless chick embryos and culturing the recombinants for seven days on the chorioallantoic membrane.

When recombined with a common dermal source, feather development is enhanced by scaleless high line as compared to scaleless low line epidermis. Against a common responding tissue, 7‐day normal back epidermis, significant differences were not found in feature inducing ability between normal, scaleless high line and scaleless low line dermis. It was concluded that, in relation to abnormal feathering, these tissue interaction reveal that the site of the scaleless gene's activity is the epidermis.

A model of tissue interactions in the development of normal and abnormal feathers is presented. According to the model, the focus of the scaleless mutation and the genes accumulated by selection for high or low feather numbers is the epidermis, the effect being that the reactivity of the epidermis to dermal stimuli is altered, Subsequently, the epidermis controls the morphogenetic organization of the dermis. The scaleless dermis is presumed to contain normal positional information for the determination of feather structure and pattern.
The production of ganglionic hypertrophy in Rana pipiens larvae
Authors: Bibb Harold D.
Published: June 2005

The periphery available to the ninth spinal ganglion of Rana pipiens larvae was effectively increased by the unilateral removal at stage V of two (8 and 10) of the three (8, 9 and 10) spinal ganglia which normally provide the bulk of the sensory innervation to the hindlimb. The levels of the resulting hypertrophy of the ninth ganglion were found to compare favorably with those produced by other workers using other techniques.

The effect of peripheral increase on mitotic activity, nerve cell number, and neuronal size (as indicated by nuclear cross sectional area) was determined. Differences in nuclear cross sectional area between neurons in hypertrophic and control ganglia were not found to be significant; however, the interaction between peripheral increase and developmental stage was found to be significant, leaving open the possibility that neurons might temporarily respond to peripheral increase by increasing in size.

Mitotic activity and neuronal numbers in ganglia with increased peripheries were greater than those in controls at all stages at which counts were made. It is concluded that either, or both, of two mechanisms could be active in producing the observed neuronal hyperplasia in hypertrophic ganglia. Daughter products from the increased numbers of mitoses could provide additional cells which differentiate to become neurons, or normally occurring neuronal loss could be reduced.

Results are discussed in the context of current ideas dealing with the regulation of neuronal numbers.
Pituitary enhancement of wolffian lens regeneration in vitro: Spatial and temporal requirements
Authors: Connelly Thomas G.
Published: June 2005

When irido‐corneal complexes (ICC's) from eyes of adult newts (Notophthalmus viridescens) are cultured on top of pituitary glands they produce advanced lens regenerates in up to 90% of the cases (this report and Connelly et al., '73). To determine if the iris and pituitary gland must be in direct contact with each other in order to produce this enhancement of lens regeneration, ICC's were cultured next to pituitary glands or separated from them by a Nuclepore filter. Cultures behaved as ICC's cultured in the absence of the pituitary gland and produced few advanced lens regenerates. To determine how long the iris and pituitary must be in contact for the enhancement to occur, ICC's were explanted and 5, 10 or 15 days later pituitary glands were placed beneath the dorsal iris pupillary margin. There was a progressive decrease in the number of advanced lens regenerates formed in cultures receiving pituitary glands later than five days after initial explantation of the iris. The conclusions drawn from these experiments are that the iris and pituitary gland must be in extensive direct contact during the first five to ten days in culture in order for pronounced enhancement of lens regeneration to occur.
Polymorphism and reproductive mode in the rotifer, Asplanchna sieboldi: Relationship between meiotic oogenesis and shape of body‐wall outgrowths
Authors: Kabay Michel E. , Gilbert John J.
Published: June 2005

Sexuality and polymorphism are closely coupled in the rotifer Asplanchna sieboldi. In a graded response to dietary tocopherol, embryos develop body‐wall outgrowths of various sizes and shapes. Also in a graded response to this compound, some of the affected females produce eggs undergoing meiotic instead of mitotic oogenesis. The haploid eggs of such mictic females develop parthenogenetically into males instead of females. The incidence of mictic females among animals with different shapes was studied among cohorts from mothers subjected to different inducing conditions. The hypothesis that external tocopherol concentrations absolutely fix the probability of meiotic oogenesis was rejected. The other extreme hypothesis, that the probability of meiotic oogenesis is fixed by morphotype, was rejected for animals at the low end of the morphotypic scale but accepted for the more strongly‐affected individuals. The probability of meiotic oogenesis is thus constant for the higher morphotypes. The ascertainment of morphotype frequencies in natural or laboratory populations may suffice for estimating the incidence of sexual forms; furthermore, studies of factors affecting the body‐wall‐outgrowth response may also bear directly upon regulation of sexual reproduction in this species.
Studies of the development of frog hemopoietic tissue in vitro. I. Spleen culture assay of an erythropoietic factor in anemic frog blood
Authors: Carver Franklin J. , Meints Russel H.
Published: June 2005

A new in vitro technique has been described for demonstrating the presence of an erythropoietic factor in the circulating blood of frogs. The assay system consisted of MC33 medium, erythropoietically active spleen cells from Rana pipiens, and plasma or serum from frogs made anemic via phenylhydrazine or bleeding. The spleen cells, which remain erythropoietically active for up to nine days, were found to incorporate 59Fe, [3H] thymidine, [3H]uridine, and [3H]leucine at a greater rate in the presence of plasma or serum from anemic versus normal frogs. The hormones triiodothyronine, prolactin, and erythropoietin were not effective in eliciting an hemopoietic response. The data presented suggest that the spleen from that adult frog is a major site of erythroid differentiation and maturation.
Ontogenetic change in molecular and functional properties of blood of garter snakes, Thamnophis sirtalis
Authors: Pough F. Harvey
Published: June 2005

At birth the blood of garter snakes (Thamnophis sirtalis) has high oxygen affinity (P50 at 25°C and pH 7.2 = 21 mm Hg), low hematocrit (14%), and a high proportion of inactive hemoglobin (44%). Growth of the snakes is accompanied by a steady decrease in oxygen affinity (P50 = 44 mm Hg in adults), increased hematocrit (to 44%), and decreased inactive hemoglobin (to 3%). These adult values are reached in the second or third year of a snake's life. There is a continuous change in the electrophoretically separable hemoglobin fractions during this period, but there is no ontogenetic change in the oxygen affinity of phosphate‐stripped hemoglobin in solution. Organic triphosphates do not fully explain the ontogenetic change in blood oxygen affinity.

Similar ontogenetic changes in blood oxygen affinity were found in two other species of snakes. The unusual morphology of snake lungs and consequent changes in pulmonary pO2 and pCO2 during ontogeny may be the basis for the unusual relationship between body size and blood oxygen affinity in snakes.
Alteration of structure and penetrability of the vitelline envelope after passage of eggs from coelom to oviduct in Xenopus laevis
Authors: Grey Robert D. , Working Peter K. , Hedrick Jerry L.
Published: June 2005

The vitelline envelope (VE) that surrounds an egg released from the ovary into the coelom of Xenopus laevis differs markedly, in structure and penetrability, from the VE surrounding an oviposited egg. In a coelomic egg, the filaments that form the VE are arranged in distinct fascicles or bundles. The exterior surface of the VE is irregular in contour and is permeated by channels. In an oviposited egg, the filaments are evenly dispersed and lack a fasciculated arrangement; the exterior surface is smooth and no channels are present. The fascicular arrangement of fibrils in the coelomic VE is maintained only at neutral pH, and is not visibly altered by the cortical reaction. VEs from coelomic eggs retain their fasciculated morphology after isolation from the egg. In an in vitro test system, sperm penetrated VEs isolated from oviposited eggs, but failed to penetrate VEs isolated from coelomic eggs. The structural transformation of the VE from the coelomic type to the oviposited type occurs in the first 1‐cm segment of the oviduct, prior to addition of jelly to the egg. Neither intact jelly, solubilized jelly, nor jelly extracts were capable of altering the structural organization of coelomic VEs, suggesting that the structural transformation of the VE is effected by some oviducal factor other than jelly.
Distribution of immunoglobulin determinants on the surface of Xenopus laevis splenic lymphocytes
Authors: Azimi Irandokht Hadji
Published: June 2005

The distribution of surface immunoglobulin (Ig) determinants on Xenopus laevis splenic lymphocytes after combination with divalent rabbit anti‐Ig coupled to ferritin was studied. The electron micrographs showed the presence of immune complexes in 67% of lymphocytes treated at 0°C–4°C. The complexes were located all around the membrane and uniformly distributed in a random fashion. The variation of ferritin grain counts on cell sections is such, that the existence of two major subclasses of Ig‐positive cells may be suggested.

Raising the temperature produced a rapid interiorization of the complexes in vesicles without any previous aggregation to form a “cap” having occurred.
Failure of immunoperoxidase staining to detect acrosin in the equatorial segment of spermatozoa
Authors: Garner Duane L. , Reamer Sharon A. , Johnson Lawrence A. , Lessley Bruce A.
Published: June 2005

An immunoperoxidase staining procedure that readily demonstrated acrosin in the rostral portion of the acrosome failed to detect acrosin in the equatorial segment of spermatozoa representing the mammalian orders artiodactyla (bull and boar), lagomorpha (rabbit) and primate (human).
Environmental effects on antifreeze levels in larvae of the darkling beetle, Meracantha contracta
Authors: Duman John G.
Published: June 2005

Acclimation of Meracantha contracta larvae collected in late summer to low temperatures, short photoperiods or low relative humidities induces production of a macromolecular antifreeze which functions to depress the freezing and supercooling points of the larvae. Overwintering larvae must be exposed to a combination of high temperature and long photoperiod before the antifreeze is lost.
Electron‐microscope investigations on the endonuclear DNA‐RNA bodies of the midgut epithelial cells of Bacillus rossius (insecta, cheleutoptera)
Authors: Bedini C. , Lanfranchi A. , Montanelli E. , Scali V.
Published: June 2005

Fourth instar larvae and adults of the stick insect B. rossius develop endonuclear bodies in about 10% of the columnar epithelial cells of the midgut. E.M. sections show that the bodies start as loose bundles of fibrils, independent from the intranucleolar chromatin. Large bodies retain a similar structure but also contain larger fibers and electron dense granules, sometimes clustered in small groups. In the nuclei containing these bodies, the other components are similar to those found in ordinary nuclei, apart from the frequent reduction in size and structural changes of the nucleoli. In the cytoplasm of both ordinary cells and those containing bodies, the rough endoplasmic reticulum is strikingly developed and towards the gut lumen many secretion vesicles are found. In EDTA treated sections the endonuclear bodies show intermingled bleached and unbleached areas, the electron density of unbleached structures being increased when compared with controls and reaching the same contrast as the fibrillar‐granular components of the nucleolus. In DNase treated specimens both the chromatin and the endonuclear bodies lose their contrast; RNase solutions digest the electron dense granules of the endonuclear bodies and the combined action of RNase and DNase further disintegrates the bodies. Ultrastructural and enzyme digestion data therefore indicate a DNA‐RNA composition for the endonuclear bodies and support, together with 3H‐thymidine uptake, the hypothesis that they are the expression of a somatic gene amplification. Their origin distinct from the nucleolar chromatin further suggests that the DNA of the bodies is not rDNA and a possible link of the bodies with the production of digestive enzymes is indicated.
Development of the compound eyes of dragonflies (odonata). I. Larval compound eyes
Authors: Sherk Truman E.
Published: June 2005

Interommatidial angles and numbers of ommatidia that viewed each segment of the visual field were mapped for a variety of dragonfly larvae from four families, selected for different behaviors and phylogenetic divergence, by measuring the directions of view of ommatidia contributing to the pseudopupil.

The size of the visual field and the amount of interommatidial angle specialization are greater than reported from histological sections, primarily because the optical axes are not perpendicular to the cornea.

Each species has interommatidial angle specializations that match its behavior. Larvae which are visual predators (family Aeshnidae) have interommatidial angles which vary from 4.9° in some parts of the eye to as little as 0.13° in the developing ommatidia at the anterior border. A foveal area can be defined with interommatidial angles of 0.2° which is the theoretical limit for ommatidia of their diameter, and is narrower than the interommatidial angles reported for adult insects. Foveal interommatidial angles measured along a vertical plane are considerably smaller than along a horizontal plane, resulting in an extremely elongate pseudopupil.

Larvae which are less dependent on vision for prey capture have correspondingly less structural specialization in the eye, but the same pattern of regional variation is still recognizable.

In contrast to the great range of interommatidial angles, ommatidial diameters are relatively uniform; the inverse relationship expected for highest visual acuity is not found.
Mitosis in beating cardiac myoblasts treated with cytochalasin‐B
Authors: Sanger Joseph W.
Published: June 2005

Time‐lapse pictures of isolated chick cardiac myoblasts grown in a medium with cytochalasin‐B reveal that normal mitotic chromosomal separation and muscle contraction can take place simultaneously. These observations indicate that the contractile stimulation for the cells' myofibrils does not affect the movement of the chromosomes and that the cell can regulate two different motile systems inside one cell.
An allelic isozyme of mouse PGK‐2 with low activity
Authors: Vandeberg J. L. , Blohm S. V.
Published: June 2005

Two allelic isozymes of PGK‐2, the testicular form of phosphoglycerate kinase, have been described previously in mice. Evidence is now presented for a third allelic isozyme, which is negatively charged and which exhibits much less enzyme activity than the other two.
The effects of actinomycin D and cycloheximide upon the ultrastructural localization of 3H‐DOPA in differentiating chick neural crest melanocytes in vitro
Authors: Brumbaugh J. A. , Schall D. G.
Published: June 2005

Cultured neural crest melanocytes from chick embryos were treated with actinomycin D or cycloheximide. The effects of these inhibitors upon melanogenesis was determined by monitoring the incorporation of 3H‐DOPA into premelanosomes and melanosomes using high resolution autoradiography.

Seven‐day cultures were treated with actinomycin D (1 μm/ml) or cycloheximide (1 μm/ml) for five hours with the terminal three hours in labeled medium (0.5 m Ci/ml). They were compared to control cultures which were labeled three hours in the absence of inhibitors. Actinomycin D reduced the quantity of silver grains associated with melanogenic organelles to 39.7%‐62.5% (different determinations) of the control value. Similarly, cycloheximide reduced the grain quantity to 58.9% of the control value.

In a second type of experiment, 6.5‐day cultures that had been subcultured once were treated with cycloheximide (1 μgm/ml) for 11 hours with the terminal three hours in 3H‐DOPA. In this case, the quantity of silver grains associated with melanogenic organelles was reduced to 22.7% of the control value.

Actinomycin D reduces 3H‐DOPA incorporation by about one‐half in from four to seven hours, while cycloheximide takes from six to seven hours to achieve a similar reduction. Therefore, RNA synthesis is at least as rate limiting as protein synthesis with regard to melanogenesis.

Based on determinations from the literature regarding the minimal half‐lives of ribosomal and transfer RNA's in cultured cells it is possible to infer that the main effect of actinomycin D was upon messenger RNA synthesis. Therefore, the ability of differentiating chick neural crest melanocytes to incorporate 3H‐DOPA is under transcriptional control.
Rapid modulation of gill Na+ + K+‐dependent ATPase activity during acclimation of the killifish Fundulus heteroclitus to salinity change
Authors: Towle David W. , Gilman Mary E. , Hempel John D.
Published: June 2005

The enzymatic properties of membrane‐bound Na+ + K+‐ATPase from gills of killifish acclimated to fresh water, to 16‰ sea water, or to 30‰ sea water appear to be identical, indicating that the same enzyme may function to absorb Na+ in low salinities and excrete Na+ at the gills in high salinities. Ammonium ion is an effective substitute for K+: in the ATPase reaction itself, in blocking phosphorylation of the ATPase protein, and in inhibiting the binding of ouabain to the enzyme. The specific activities of the Na+ + K+‐ATPase in the three different salinities are consistent with the expected Na+ pumping rates: higher in fresh water and 30‰ sea water than in 16‰ sea water. Within one‐half hour after transfer of killifish from one salinity to another, gill Na+ + K+‐ATPase activities reach equilibrium levels. The rapid increase in Na+ + K+‐ATPase activity in gill microsomes of fish acclimating from fresh water to 30‰ sea water is accompanied by a slow decrease in the number of binding sites for ouabain, supporting the idea that acclimation to short‐term salinity changes may involve modifications in the catalytic rate rather than the number of Na+ + K+‐ATPase molecules.
Fluorescence identification of zoochlorellae: A rapid method for investigating alga‐invertebrate symbioses
Authors: Williamson Craig E.
Published: June 2005

Using fluorescence microscopy I have developed a technique for the rapid identification and enumeration of zoochlorellae which does not require sectioning. Chlorophyll in algal symbionts fluoresces bright red when excited by ultra‐violet light. In a test of this system using green and white Spongilla lacustris I found a ratio of 42:1 (green:white) in the number of symbionts and a similar ratio of 36:1 in the amount of chlorophyll a and b present.
Chemotactic behavior of the sperm of chitons (Mollusca: Polyplacophora)
Authors: Miller Richard L.
Published: June 2005

Observations of sperm behavior in the vicinity of gradients of egg‐water or alcohol extracts of whole freshly‐spawned eggs of several chitons reveal what appear to be directed movements of sperm up the gradient, resulting in the aggregation of motile sperm at the gradient source. Plots of the tracks of the sperm approaching the gradient source show that the cells increase the time during which they move toward the source and decrease the time spent moving away. Although this resembles the kinesis behavior shown by bacteria in a gradient, the path directions are markedly non‐random. The reorientation behavior of thigmotactic sperm involves enlargement of the normal circular path diameter in the direction of the source and an alternation of tight loops and wide circular arcs, with the latter made in the direction of the source. The form of the path of attracted chiton sperm is like that observed during chemotaxis of the sperm of the hydroid Tubularia and the tunicate Ciona and resembles the behavior of Ciona sperm in that there is no increase in velocity as the cells move up the gradient. However, unlike the cnidarian and urochordate cases, the attracting substances extracted from chiton eggs do not act species‐specifically.
The effect of nerve growth factor and limb regeneration on the spinal and sympathetic ganglia of Triturus
Authors: Grillo R. S. , Detmar C. F. , Mitchell O. G.
Published: June 2005

In Triturus administration of NGF causes hypertrophy of neuronal perikarya of third dorsal root ganglia and post‐subclavian sympathetic ganglia.

Two classes of neurons were characterized cytologically in the third dorsal root ganglia. Some evidence is presented which indicates that Class I neurons respond more vigorously to NGF. It is suggested that Class I neurons are similar to the medio‐dorsal neuroblasts of chick embryos in their response to NGF.

Forelimb amputation did not cause neuronal hypertrophy in either third dorsal root ganglia or post‐subclavian sympathetic ganglia.

The incorporation of (3H)‐uridine increases to a highly significant extent in third dorsal root ganglia following NGF treatment or limb amputation. When NGF treatment and limb amputation were combined, no further increase in (3H)‐uridine incorporation was noted. This suggests that RNA synthesis is maximally stimulated by either NGF treatment alone or limb amputation alone.
Persistence of circadian activity rhythms in pinealectomized European Starlings (Sturnus vulgaris)
Authors: Rutledge James T. , Angle Marlane J.
Published: June 2005

Surgical removal of pineal glands from adult male European Starlings (Sturnus vulgaris) does not alter circadian perch‐hopping activity rhythms characteristic of this species maintained in constant darkness. The average free‐running period of the activity rhythms of ten pinealectomized birds was 24.61 hours, compared to the previously reported period of 24.48 hours for intact starlings under identical conditions. These results conflict with those reported for three other passerine species in which pinealectomy abolishes circadian activity patterns. In addition, the data do not support the recently proposed model of Menaker and Zimmerman that suggests that the pineal gland is the site of the self‐sustained oscillator in the circadian timing system of birds.
Surface modification of guinea pig sperm during in vitro capacitation: An assessment using lectin‐induced agglutination of living sperm
Authors: Talbot Prudence , Franklin L. E.
Published: June 2005

Plant lectins have been used to advantage to study carbohydrate‐containing cell surface receptors in numerous systems. In this study, a simple, reliable assay was developed to quantitate lectin‐induced agglutinability of sperm. This assay was used successfully to compare some of the surface properties of uncapacitated and capacitated guinea pig sperm. Capacitation was induced by incubating sperm in minimum capaciting sperm in minimum capacitation medium (MCM) or modified Tyrodes solution (T‐PL). Control incubations were done in Ham's F‐10 or Hank's balanced salt solution which do not support capacitation. At timed intervals during incubation, sperm samples were assessed for pattern and degree of lectin‐induced agglutination. Results establish that: (1) soybean agglutinin (SBA) and to a lesser extent concanavalin A (Con A) induced agglutinability of guinea pig sperm increase during in vitro capacitation in MCM; (2) a similar increase in SBA induced agglutinability occurs during capacitation in T‐PL, but not in the non‐capacitating media; and (3) for sperm incubated in MCM or T‐PL, there is a significant increase in tail to tail agglutination after capacitation. The results with SBA demonstrate that D‐galactose and/or N‐acetyl‐D‐galactosamine containing receptor sites or the guinea pig sperm surface are affected by capacitation, and this effect occurs, at least in part, in the sperm tail. Possible explanations for the observed increase in agglutinability are discussed. The agglutination assay may prove useful as a direct test for the occurrence of capacitation and may be especially valuable for species having a small acrosome or limited number of eggs.
Z‐line and supercontraction in the hydraulic muscular systems of insect larvae
Authors: Carnevali M. Daniela Candia
Published: June 2005

An electron microscopic study has been made on the body wall muscles from Lepidoptera (Noctua pronuba, Philosamia cynthia) and Diptera larvae (Tipula tipula), whose locomotion is based on a hydraulic muscle antagonism.

All the fibers examined had interrupted Z‐bands, formed of single dense bodies, irregularly placed around the sarcomere; myosin filaments could pass through the spaces between one Z‐body and the next, making it possible for the sarcomere to shorten its resting length by up to 60%. In supercontracted muscles, both the thick and the thin filaments pass through the Z‐line; since these actin filaments are very long, they can overlap and interact with the myosin filaments of the adjacent sarcomeres.

The muscles examined can be placed in the category of supercontracting muscles and can be considered a type of striated muscle, with morphological and functional characteristics similar to those of helical or smooth muscle.
Cell proliferation in the intestinal epithelium of Xenopus laevis tadpoles
Authors: Marshall J. A. , Dixon K. E.
Published: June 2005

Light microscope, electron microscope and autoradiographic techniques were used to determine whether, in the small intestinal epithelium of feeding tadpoles of Xenopus laevis, proliferation is limited to particular cells or to particular regions. Mitotic figures were classified as apical, medial or basal according to their position relative to the gut lumen. Apically dividing cells represent 75% of all mitoses and were identified on histological and ultrastructural criteria as specialized principal cells or rarely, as specialized gland cells. This interpretation was confirmed by autoradiographic evidence that specialized principal and gland cells incorporate (3H) thymidine into DNA. Basally dividing cells represent 25% of all mitoses and medial mitotic figures are very rare. Histological and ultrastructural evidence indicated that basal and medial mitotic figures are due to the division of intra‐epithelial lymphocytes and it was demonstrated that lymphocytes incorporate (3H) thymidine into DNA. Growth and replacement in the epithelium are therefore due to the mitotic activity of specialized cells. The results also suggest that all specialized cells can divide and that proliferation is not localized in particular regions of the epithelium as it is in other vertebrates. The significance of these conclusions for the interpretation of nuclear transplantation experiments using donor nuclei from intestinal epithelial cells is briefly discussed.