bluuebunny/crossref_metadata_2025 huggingface dataset:
Trochlear‐oculomotor nerve interactions in Xenopus laevis tadpoles: A temporal study
Authors: Fangboner Raymond F.
Published: June 2005

When the trochlear nerve(NIV), which innervates the superior oblique muscle (SOM), is crushed or cut at stages 48–49 in Xenopus tadpoles, fibers from the oculomotor nerve (NIII) sprout and invade the SOM. The maximal percentage of specimens having at least one oculomotor nerve fiber on the SOM on a given day increased from 9.1% following a single crushing of NIV to 84.2% following three successive severings of NIV and the average number of silver‐impregnated NIII fibers per specimen increased from 0.23 ± 0.16 (mean ± S.E.M.) in the single‐crush experiment to 7.35 ± 1.33 in the triple‐cut experiment. This increase directly reflects the delay in the return of NIV. As NIV returns to the SOM, a portion of the inappropriate innervation is lost; while another portion appears to be stable and is in evidence 90 days after a single sectioning of NIV. The more rapidly NIV returns to the SOM, the more complete is the displacement of the NIII fibers. This suggests that the association between NIII and the SOM changes with time so that easy displacement of the inappropriate innervation is likely only when the reinnervation by the appropriate nerve fibers is rapid.
The origin of yolk‐DNA in Xenopus laevis
Authors: Opresko Lee , Wiley H. Steven , Wallace Robin A.
Published: June 2005

Xenopus laevis serum and plasma was found to contain an average of 25 μg DNA/ml. Isolated X. laevis oocytes incubated in medium containing 25 μg DNA/ml labeled with either 125I, 32P or 14C and from three different sources (bovine, E. coli and X. laevis), incorporated the label at an average rate of 0.11 ng·mm−·hr−1. Sucrose gradient fractionation of oocytes revealed that 40–75% of the acid‐precipitable label incorporated was associated with the yolk platelets. Additional incubations of oocytes in unlabeled medium demonstrated that the DNA incorporated into the yolk platelets was undergoing turnover; only 20% of the yolk‐associated DNA was still present after a one‐week incubation. Our data suggest that yolk‐DNA arises by the adventitious uptake of DNA present in the maternal serum by vitellogenic oocytes.
Reduction of sodium dependent stump currents disturbs urodele limb regeneration
Authors: Borgens Richard B. , Vanable Joseph W. , Jaffe Lionel F.
Published: June 2005

We have asked the question whether the natural electric currents which leave urodele limb stumps are in any way needed for their regeneration. As an initial test, we have greatly reduced such currents in the tiger salamander, Ambystoma tigrinum, by applying 0.5 mM amiloride to the stump skin or by immersion of the animals in sodium depleted media. We have also reduced such currents in the red spotted newt, Notophthalmus viridescens, by such immersion. Limb regeneration in half of the amiloride‐treated animals was either entirely blocked or grossly deficient, while the others regenerated normally. Limb regeneration in sodium depleted media was consistently inhibited for some weeks but then recovered.

These results are consistent with the hypothesis that stump currents are in some way needed for normal regeneration.
Stages of forelimb regeneration in Ambystoma maculatum
Authors: Stocum David L.
Published: June 2005

A series of normal stages describing the regeneration of larval A. maculatum limbs after amputation through the upper arm or wrist is described. Nine discrete stages were recognized, based on external morphological and associated histological features. These stages are Initial Dedifferentiation (ID), Early Bud (EB), Medium Bud (MB), Late Bud (LB), Early Redifferentiation (ER), Notch (N), 2‐Fingerbud (2‐FB), 3‐Fingerbud (3‐FB) and 4‐Fingerbud (4‐FB). Similarities and differences between this and other staging systems for urodele limb regeneration are discussed. The absence of osteoclasts was a striking feature during dedifferentiation of the wrist, in contrast to their presence in large numbers during dedifferentiation of the upper arm.
Reproductive failure and maternal‐fetal relationship in a Peromyscus species cross
Authors: Maddock M. B. , Chang M. C.
Published: June 2005

Mating, fertilization, implantation, prenatal mortality, fetal and placental size, and placental ultrastructure were studied in intraspecific and interspecific crosses involving Peromyscus maniculatus and P. polionotus. Failure to mate was a major factor in interspecific crosses and was much more pronounced in crosses between P. polionotus females and P. maniculatus males than in the reciprocal cross. Failure of implantation following mating, however, was more pronounced in crosses between P. maniculatus females and P. polionotus males. Failure of implanted embryos to survive to term was a factor in crosses between P. polionotus females and P. maniculatus males. Comparison of the placental labyrinth of conceptuses from intraspecific and interspecific crosses revealed no differences at the ultrastructural level. The relationship of these observations to the evolution of isolating mechanisms in mammals and to physiological aspects of the developing maternal‐fetal relationship are discussed. A model of placental and fetal size inheritance is presented.
The distribution of cells in the upper forelimb of the axolotl, Ambystoma mexicanum
Authors: Tank Patrick W. , Holder Nigel
Published: June 2005

The number and relative density of cells in specific regions of the upper forelimb of the axolotl were compared. Selected transverse sections taken from the distal one‐third of the upper forelimb were analysed by light microscopy. Comparisons were made between the total numbers of cells observed in each of the major tissue components of the forelimb (epidermis, dermis, muscle, connective tissues and skeletal tissues). Comparisons were also made between the total numbers of cells located in the major limb quadrants (anterior, posterior, dorsal and ventral). In addition, cellular density (cells/mm2) was compared among eight limb sectors. The results indicate that the posterior quadrant of the upper forelimb contains more cells than any other forelimb quadrant. Cellular density did not favor a particular forelimb quadrant. These results suggest that the proposed clumping of positional values in the posterior region of the forelimb in the axolotl (Tank, unpublished data) may correspond to the presence of a larger number of cells in the posterior quadrant, but does not correspond to a higher cellular density in that region of the upper forelimb.
Separation of the epithelial and mesenchymal components of the newt limb regenerate with salt
Authors: Jasch Laura G.
Published: June 2005

After incubation of isolated forelimb regenerates of Notophthalmus (Triturus) viridescens at all developmental stages for 60 minutes at 37°C in a salt medium containing 111 mM sodium chloride, 5.6 mM potassium chloride and 100 mM sodium phosphate buffer at pH 7.5, the wound epithelium of each regenerate was removed intact from its underlying mesenchymal component. The suggestion is made that the salt medium is an effective epithelialmesenchymal separating agent due to a combination of its hypertonicity, high ionic strength and the fact that the medium precipitates calcium as calcium phosphate. Attempts to dissect away the epithelium from the mesenchyme after incubation of isolated regenerates in sodium phosphate containing 1% or 3% Difco 1:250 trypsin, 10 mM EDTA or 150 units collagenase/ml medium were unsuccessful. Epidermis of adult newt forelimb skin was removed only after extended incubation of the forelimbs in the salt medium for three hours at 37°C or after freezing isolated forelimbs in buffer and subsequent thawing.
Comparison of DNA polymerase activity and cell division in normal and delayed‐implanting mouse embryos
Authors: Weitlauf H. , Kiessling A. , Buschman R.
Published: June 2005

Cell division stops in mouse blastocysts during the prolonged, free‐living phase associated with delayed implantation. It is not known how the embryos are rendered mitotically dormant and then reactivated to implant at a later time, and the present experiments were undertaken to determine whether or not changes in the level of DNA polymerase in the embryos could play a role in the regulation of cell division.

Unattached normal and delayed‐implanting blastocycts were recovered from pregnant mice at intervals between the fourth and the fifteenth day of pregnancy, and the number of cells and amount of DNA polymerase in the embryos were determined in order to correlate amount of enzyme with the rate of cell division. The number of cells in both types of embryos increased equally until noon of day 5. However, as expected, the rate of cell division in the delayed implanting blastocysts then slowed and there was no further increase in the number of cells beyond day 7 or 8. Termination of the dormant phase of delayed implantation by the injection of 17 β‐estradiol, resulted in a resumption of cell division within 24 hours. The total amount of DNA polymerase activity in normal blastocysts increased 200% between day 4 and day 5. In contrast, there was only a 60% increase in enzyme activity in the delayed implanting embryos during this interval. The level of polymerase activity in the delayed implanting embryos then decreased and remained depressed for the several days of the dormant period. Injecting 17 β‐estradiol on day 9 resulted in an increase (120%) in polymerase activity. Although the amount of DNA polymerase per cell in the dormant embryos was low by comparison with that in normal embryos, it was higher than that in adult spleen (a tissue that is active in DNA synthesis) and therefore it appears likely that other mechanisms are involved in regulating cell division in the embryos.
Liquid chromatographic demonstration of catecholamine release in fish heart
Authors: Cameron John S. , O'Connor Edward F.
Published: June 2005

High‐pressure liquid chromatography (HPLC) was used to assay for catecholamines released into the heart of the goldfish (Carassius auratus L.) upon stimulation of vagal nerve fibers. Stimulation induced the release of norepinephrine, epinephrine and dopamine into the lumen of the perfused, isolated heart. The results suggest that heart activity in teleosts is directly modulated by functional adrenergic, cardioacceleratory nerve fibers.
Modifications in the arrangement of thick and thin filaments in transforming shrimp muscle
Authors: Mellon DeForest , Stephens Philip J.
Published: June 2005

The fine structure and arrangement of thick and thin filaments in the main closer muscle were investigated for pincer, snapper and transforming claws of Alpheus armillatus. The snapper main closer muscle is composed of a uniform population of tonic‐type fibers with long sarcomeres and a thin‐to‐thick filament ratio of 7 to 1. In contrast, the pincer main closer muscle is made up of two populations of fibers. Phasic type fibers have large diameters, short sarcomeres and a thin‐to‐thick filament ratio of 3 to 1. Intermediate‐type fibers have smaller diameters, intermediate sarcomere lengths and a thin‐to‐thick filament ratio of between 5 and 6 to 1. In the pincer the thick filaments have a hollow appearance. During the transformation of a pincer to a snapper claw, the main closer muscle fibers develop tonic‐type characteristics. The sarcomeres increase in length, and the ratio of thin‐to‐thick filaments increases to 7 to 1. Furthermore, the thick filaments increase in both length and diameter, and develop a more uniform structure. These findings suggest that changes in myosin packing accompany transformation, with predictable consequences in both thick filament diameter and thin filament/thick filament ratio.
Alteration of locomotor behavior in wolf spiders carrying normal and weighted egg cocoons
Authors: Moffett Stacia , Doell Gail S.
Published: June 2005

The slow locomotion (5–11 cycles/sec) of unloaded wolf spiders, Pardosa tristis, was compared with that of spiders moving at similar speeds supporting a normal or an artificially weighted egg cocoon attached to the opisthosoma or in the pedipalps. Spiders carrying an egg cocoon attached to the opisthosoma elevated the opisthosoma, while spiders carrying a cocoon in the pedipalps elevated the prosoma and curved the opisthosoma downward. Both loaded groups gathered their legs more closely under them and took shorter steps than unloaded spiders. Protraction/retraction ratios increased as a function of increasing walking speed and decreased as a function of increasing loads.
Study of intraclonal conjugation in Chilodonelia steini. Evidence of abortive conjugation
Authors: Kaczanowski Andrzej , Radzikowski Stefan , Malejczyk Jacek , Polakowski Igor
Published: June 2005

Mating and conjugation in the ciliate Chilodonella steini has been examined. Only intraclonal conjugation has been found thus far in this species. Stable opposite mating types have not been observed, even after extensive single cell isolations and the observation of cell lines following two consecutive generations of inbreeding. Following intraclonal conjugation, two kinds of selfing lines appear: 1) lines that enter long immaturity periods, 2) lines that do not enter immaturity at all, but maintain a permanent ability to pair. These lines do not yield immature progeny after a subsequent conjugation. Immature lines result from true conjugation as expected, whereas those lines that do not enter immaturity result from an abortive process. During normal conjugation the new macronuclear anlagen develop and the old macronucleus is resorbed. During abortive conjugation the new macronuclear anlagen also develop but the old macronucleus is not resorbed. Eventually the old macronucleus, instead of the new one, divides to provide a somatic nucleus for the progeny. Thus macronuclear retention occurs in some lines of Ch. steini similar to that observed in senescent lines of Tetrahymena thermophila.
Potentiation of the cGMP‐induced Guinea pig acrosome reaction by zinc
Authors: Santos‐Sacchi Joseph , Gordon Mildred , Williams William L.
Published: June 2005

The addition of 8 bromo cGMP (10 mM) immediately (∼2 min) upon suspension of Guinea pig sperm in glucose‐free BWW medium induces a significant number of acrosome reactions within minutes. The simultaneous addition of micromolar concentrations of ZnCl2 (25–1000 μM) potentiates the cGMP effects. Mid‐micromolar concentrations were able to dramatically increase the percentage of acrosome reactions by a factor of 6.5 over 8 bromo cGMP alone. The induction of acrosome reactions was dependent upon external Ca++, and it is suggested that in this species Zn++ flnctions by affecting cyclic nucleotide metabolism and/or Ca++ flux.
Direct visualization of dynamic membrane events in cilia
Authors: Bloodgood Robert A.
Published: June 2005

Cilia of the sea urchin embryo exhibit rapid translocation of marker objects along their surface membrane.
The effect of pinealectomy on hibernation in two species of seasonal hibernators, Citellus lateralis and C. richardsonii
Authors: Harlow Henry J. , Phillips John A. , Ralph Charles L.
Published: June 2005

Pinealectomies and radical sham pinealectomies were performed on golden‐mantled and Richardson's ground squirrels approximately 1 month prior to the date of normal immergence for each species. Pinealectomy did not disrupt the hibernating rhythm of either species. These results suggest (1) that the pineal is not required for torpor to be initiated or maintained, (2) that either melatonin is not required for hibernation or another melatonin‐producing organ compensates for the loss of the pineal, and (3) that the influence of the pineal is seasonal and had already acted prior to its surgical removal.
Methemoglobin reduction in crocodile blood: Are high levels of MetHb typical of healthy reptiles?
Authors: Gruca Margie , Grigg Gordon C.
Published: June 2005

In 82 wild‐caught Crocodylus porosus, levels of NADH‐MetHb reductase and GSH seem adequate to maintain hemoglobin in its reduced functional state. Studies of C. porosus erythrocytes in vitro show reduction of metHb in the presence of lactate, glucose and plasma, but not pyruvate.

These findings, together with recent data which show low metHb in a variety of reptiles, cast doubt on the accepted view that high levels of MetHb are typical of healthy reptiles.

One explanation for the sharp contrast between earlier and more recent data could be technical. We found low metHb in Crocodylus johnstoni, Chelodina longicollis and Sphenomorphus quoyi. However, high and variable values reminiscent of many of the earlier data were obtained by omitting final centrifugation prior to spectrophotometry. Interestingly, this step is not part of the standard clinical method but is necessary in analyses of blood with nucleated red cells. These observations suggest that high metHb may not be typical of reptiles after all.
The effects of constant light and constant darkness on the pineal organ of the goldfish, Carassius auratus
Authors: McNulty John A.
Published: June 2005

Goldfish (Carassius auratus) were subjected to both long‐ and short‐term (1, 3, 6, and 170 days) constant light or constant darkness to determine the effects of environmental lighting on the morphology of photoreceptor cells in the pineal organ. Morphometric analysis of electron micrographs from each experimental group suggested that the effects of constant darkness are morphologically expressed only after long‐term (6 months) exposure. These included an increase in the volume of photoreceptor and phagocytic cells, area of rough endoplasmic reticulum, and volume of mitochondria per photoreceptor cell, and a decrease in the size of individual Golgi bodies. On the other hand, the response to constant light occurred generally within the first 6 days. Under these conditions, there was a reduction in outer‐segment volume, but an increase in both the volume of Golgi per photoreceptor cell and size of individual Golgi bodies. Synaptic ribbons in these specimens were longer at every time sampled. The results of this study provide evidence that photoreceptor cell organelles involved in synthesis and secretion, as well as photosensory functions, are influenced by environmental lighting.
Dissection of circadian organization of Aplysia through connective lesions and electrophysiological recording
Authors: Roberts Michael H. , Block Gene D.
Published: June 2005

(1)Aplysia californica exhibit a diurnal circadian locomotr rhythm (Strumwasser, '67). The rhythm appears to be timed by circadian pacemakers located within the eye, although extraocular photoreceptors and pacemakers also influence locomotor behavior (Strumwasser, '73; Lickey et al., '77). (2) The present study was undertaken in an attempt to identify the pathways ganglia, which are responsible for generatating locomotor movements. A lesion study was performed in which either of the two pairs of bilaterally symmetrical cerebral connectives were cut and the effect on locomotor behavior evaluated. (3) The results indicate that the cerebro‐pleural connectives are not involved in control of locomotor acitivity (Fig. 2). On the other hand, the cerebro‐pedal connectives are critical for ocular and extraocular control of locomotor thythmicity (Figs. 3,4). Animals with bilateral cerebropedal lesions are arrhythmic on light cycles. (4) Multiunit recording in vivo and in vitro revealed the presence of a descending signal in the cerebropedal connective upon the application of a light pulse to the animal. Further experimentation localized the origin of these signals to the tentacles, rhinophores and eyes (Figs. 6, 7). (5) We conclude that the elements comprising the circadian system of Aplysia are located in a restricted portion of the central nervous system including the cerebral and buccal ganglia, and sensory structures served by cerebral or buccal nerves.
Can differences in limb regeneration ability between amphibian species be explained by differences in quantity of innervation?
Authors: Scadding Steven R.
Published: June 2005

This investigation was designed to test the hypothesis that there is a direct relationship between quantity of innervation and regenerative capacity. This was done by measuring the quantity of innervation in 13 different species of amphibians chosen to represent a spectrum of regenerative abilities. When looking at the five urodele species alone, or when comparing urodeles and eight anuran species, the results show a lack of correlation between regenerative capacity and quantity of innervation. However, if the anurans alone are considered, the four species in which regeneration has been observed all have levels of innervation greater than in the four species that do not regenerate. This suggests the possibility that an adequate quantity of innervation may be a limiting factor for limb regeneration in anurans, but is not a limiting factor in urodeles.
Specificity of sperm‐zona interaction
Authors: Swenson Christine E. , Dunbar Bonnie S.
Published: June 2005

The specificity of early sperm‐zona interactions in vitro was studied using gametes from the mouse, rabbit, pig, and human. Mouse epididymal spermatozoa, capacitated in vitro, bound to the zonae of intact mouse oocytes and zona fragments removed mechanically from oocytes. When viewed with the scanning electron microscope (SEM), spermatozoa were found adherent more frequently to the external (cumulus) surface of the zonae than the internal (oocyte) surface. Noncapacitated mouse spermatozoa or spermatozoa incubated with zonae in the absence of external calcium did not bind to homologous zonae. By contrast, fresh, epididymal mouse spermatozoa and mouse spermatozoa capacitated in vitro appeared to attach equally well to both surfaces of zonae and zona fragments from rabbit and pig oocytes. Rabbit spermatozoa “capacitated” in vivo as well as noncapacitated rabbit spermatozoa, attached rapidly to both inner and outer surfaces of zonae from rabbit, mouse, and pig oocytes. This reaction was not dependent on external calcium. Human spermatozoa did not display any tendency to adhere to zonae from the rabbit, mouse, or pig. The results of these studies suggest that spermatozoa can associate with zona in a nonspecific as well as a specific manner. The use of heterologous systems in addition to homologous systems in sperm binding assays may be useful in distinguishing these two types of interaction.
Motor program of an intersegmental reflex in crayfish
Authors: Page Charles H. , Jones Kenneth A.
Published: June 2005

Flexion of a merocarpal joint of a single leg initiates a discharge of the efferent neurons that produces postural abdominal extension in the crayfish. This intersegmental reflex is characterized by the excitation of those efferents whose effects are synergistic to extension, and the incomplete suppression of those efferents that are extensor antagonists. Comparison of the latencies and discharge patterns that are generated in response to leg flexion with those produced during “command fiber” stimulation suggests that this intersegmental reflex is mediated by the activation of more than one “command fiber” interneuron.
Fish erythrocytes are bicarbonate permeable: Problems with determining carbonic anhydrase activity using the modified boat technique
Authors: Heming T. A. , Randall D. J.
Published: June 2005

Effects of foaming agents (blood plasma, bovine serum albumin, polyvinyl‐pyrrolidinone) and defoaming agents (octanol, No‐foam) on manometric determination of carbonic anhydrase activity in intact erythrocytes of fish were examined. Foaming agents abolished the activity of red cells. Defoaming agents increased the activity and negated any differences in carbonic anhydrase activity between whole blood (red cells in plasma) and “Cortland” blood (red cells in saline). It is concluded that effects of plasma on the carbonic anhydrase activity of intact erythrocytes of fish measured using the modified boat technique are largely non‐specific and related to reagent foaming during mixing, rather than to the action of a specific enzyme inhibitor.
Regeneration of transplanted chelae in two species of fiddler crabs (Uca pugilator and Uca pugnax)
Authors: Trinkaus‐Randall V.
Published: June 2005

The extensor muscle and chela of unoperated and transplanted regenerated limbs from two species of Uca were examined to test the theory of neurotrophic control on crustacean muscle. Initially, tuberculation patterns, sensory hair number, and claw shape of the transplanted regenerated limb resembled those of the donor. Sarcomere lengths were donorlike except when the transplant was from male to female. Eventually the transplanted regenerated limb acquired some recipientlike features, although the claw shape and sarcomere length measurements of secondary regenerates resembled those of the donor. Because of these findings, it is no longer possible to hypothesize that innervation alone controls the growth and differentiation of muscle.
Development of a latex‐conjugated immunocytological marker for scanning electron microscopic analysis of quail–chick chimeras
Authors: Meier Stephen , Drake Christopher
Published: June 2005

Quail–chick chimeras are created by transplanting pieces of quail tissue to chick. We have used antibodies combined with a cell surface marking technique [modified after Molday et al.('75)], to facilitate scanning electron microscopic (SEM) identification of quail cells in such chimeras. First, antibodies to quail RBCs were raised in rabbits by intravenous injection. Rabbit anti‐quail RBC serum was precipitated by ammonium sulfate, purified by DEAE chromatography, and cross‐absorbed with chicken RBCs. Second, sheep anti‐rabbit IgG was purchased commercially and further purified by affinity chromatography. Third, 900‐Å‐diameter latex beads were synthesized by aqueous emulsion copolymerization of methacrylates. Spheres were bound with diaminoheptane to create an extension arm which was further derivatized in a two‐step glutaraldehyde procedure. Purified sheep IgG was bound to the aldehyde‐activated spheres, with uncoupled sheep IgG removed by sucrose density centrifugation. To test the marker, rabbit anti‐quail IgG was added to 1% diluted quail RBCs. After washing, sheep anti‐rabbit IgG bound spheres were introduced. Washed cells were fixed in one‐half strength Karnovsky's and processed for SEM. Quail RBCs were uniformly decorated with beads, containing 2,000 beads per cell. Similarly treated chick RBCs show no binding to beads. Likewise, quail RBCs not pre‐treated with the rabbit IgG do not bind beads. Prefixed quail RBCs still bind latex‐conjugated beads, although at somewhat reduced levels. When mixtures of quail and chick RBCs were processed for identification: (1) sphere labeling was an “all or none” phenomenon; (2) the proportion of bead‐decorated cells observable in the SEM was the same as the proportion of quail RBCs provided in the initial mix; and (3) morphologically distinguishable embryonic chick RBCs did not label whereas under the same conditions, quail RBCs do. We further demonstrate that rabbit antibodies prepared by injection of stage 4 quail primitive streaks can be used to specifically label quail epiblast and mesoblast cells, providing markers for at least two germ layers. It is now possible to combine grafting techniques of known success, with SEM analysis of the chimera.
Edema formation and impaired O2 transfer in ringer‐perfused gills of the eel, Anguilla australis
Authors: Ellis A. G. , Smith D. G.
Published: June 2005

Isolated gills of the eel (Anguilla australis) were perfused with various solutions and subsequently examined using light or scanning electron microscopy. Oxygen transfer was measured in some perfusions. Ringer perfusion impaired O2 transfer and caused irreversible structural damage to the gills. Severe edema was consistently observed as a massive enlargement of the secondary lamellar subepithelial space. Addition of plasma protein substitutes (1–8% polyvinylpyrrolidone; 2–3% dextran) to Ringer perfusates failed to prevent edema, even when used in combination with 0.2% bovine serum albumin. Perfusion with fresh mammalian blood or plasma for up to 30 min did not cause edema, plasma perfusion significantly improving O2 transfer.

Unless autologous blood or plasma is available, mammalian plasma is the most suitable perfusate for exchange studies in fish gills.

As yet unidentified proteins in plasma probably reduce the pore dimensions of the pillar cell flanges, thereby reducing colloid loss from the vascular space.
The blockade of pigment displacement in swordtail erythrophores by microinjection of antiactin antibody
Authors: Akiyama Toyoko , Matsumoto Jiro
Published: June 2005

When antiactin antibody produced against carp skeletal muscle actins was microinjected into monolayer‐cultured swordtail erythrophores, pigment displacement was almost completely blocked. Moreover, the injected antibody was equally effective at blocking the aggregation of dispersed pigment and the dispersion of aggregated pigment. If antibody saturated with carp actins was microinjected, no such blockade occurred.

Microinjection of phalloidin or DNase I into these cells brought about an incomplete inhibition of their pigment displacement. These two drugs tended to inhibit pigment dispersion more than aggregation, suggesting that actins are differently involved in the two phases of pigment movement. The results all indicate that actins are functional elements in the pigment displacement of swordtail erythrophores, and that G‐F transformations of these molecules play little or no role in pigment aggregation, but are implicated in some way in dispersion.
Development of peroxisomes in amphibians. III. Study on liver, kidney, and intestine during thyroxine‐induced metamorphosis
Authors: Dauça M. , Calvert R. , Menard D. , Hugon J. S. , Hourdry J.
Published: June 2005

This investigation was undertaken to study the ontogeny of hepatic, renal, and intestinal peroxisomes and/or microperoxisomes during thyroxine‐induced anuran metamorphosis. Catalase activity was localized cytochemically after incubation in DAB medium, and studied biochemically by a spectrophotometric method. Our morphological and biochemical investigations suggest the formation of a new population of peroxisomes during the hormonal treatment. This is obvious especially for microperoxisomes of the intestinal epithelium since the larval tissue is completely replaced by a new layer during thyroxine‐induced metamorphosis. For the peroxisomes of hepatocytes and kidney proximal tubule cells, our assumption is based on the following observations: (1) The number of peroxisomes increases in liver and kidney during thyroxine treatment; (2) this proliferation is accompanied by an enlargement of renal peroxisomes; and (3) 16 days after the beginning of the hormonal treatment, 5.4‐ and 2.4‐fold increases are found for the specific activities of hepatic and renal catalase, respectively. A temporal coordination exists between the structure and the metabolism of peroxisomes and mitochondria during thyroxine‐induced metamorphosis.
Pattern of growth in a temperate zone anuran (Bufo viridis Laur.)
Authors: Jørgensen C. Barker
Published: June 2005

Growth in body length and mass was followed in 1‐year‐old toads Bufo viridis collected early August, kept in the laboratory at 20°C, and fed meal worms ad libitum for 24 h once or twice a week. The nutritional condition of the toads was evaluated from the condition index (CI) = 1,000 × body mass (g) × length (cm)−3. The rates of growth in length were high initially, in August and September, and then dropped to insignificant levels. Growth was abruptly resumed in spring, and growth rates were high in March to May. The CI increased to a maximum in September. During the period of growth stagnation it tended to decrease. After growth was resumed in spring, the CI again increased, but with a delay. During autumn the toads allocated food for lean growth and fattening, and eventually reduced feeding and growth, according to the pattern typical of toads in nature. This pattern was not affected by artificial long days. It is thus suggested that 1‐year‐old Bufo viridis exhibit inherent control of the behavioral and physiological mechanisms that prepare the organism for hibernation. During the spring period of growth the toads were out of phase with toads in nature. However, the synchrony of growth among the experimental toads continued. It is suggested that the second growth period also may represent an inherent functional pattern that was prematurely initiated under the conditions of the experiment.
Sperm reception by an egg microvillus in the polychaete, Tylorrhynchus heterochaetus
Authors: Sato Masanori , Osanai Kenzi
Published: June 2005

A fine‐structure study of sperm‐egg interactions during normal fertilization in the polychaete Tylorrhynchus heterochaetus was carried out. Sperm initiated an acrosome reaction on the outermost layer of the chorion, which consisted of four layers. After the acrosomal vesicle opened, the subacrosomal space expanded to become a lobular acrosomal process, the frontal margin of which penetrated the first and second layers of the chorion and adhered to the third layer. The process did not penetrate the third and fourth layers. Within 1 min of insemination the acrosomal process of the fertilizing spermatozoon fused with a microvillus projecting from the egg through the chorion. The microvillus thickened and developed into a sperm penetration cone. The sperm nucleus entered the egg cortex through this cone 20–25 min after insemination. The result shows that the tips of egg microvilli are sites for sperm reception.
Mollusk shell organic matrix: Fourier transform infrared study of the acidic macromolecules
Authors: Worms Daniele , Weiner Stephen
Published: June 2005

Ion‐binding ligands and the conformations of some of the acidic matrix macromolecules present in the shells of a gastroped, a bivalve, and a cephalopod, are investigated in vitro by Fourier transform infrared spectroscopy. The complex assemblage of matrix constituents present in the EDTA‐soluble fraction is first separated into two quite different classes of macromolecules by a reversed‐phase chromatographic procedure. Infrared spectra indicate that the constituents of one class, which are proteins rich in aspartic acid, adopt the β‐sheet conformation upon binding calcium to the protein carboxylate groups. The second class of matrix constituents contains proteins rich in serine that appear to be associated with relatively large amounts of polysaccharide. They also bind calcium and upon doing so undergo a conformational change.
The influence of tunichrome and other reducing compounds on tunic and fin formation in embryonic Ascidia callosa Stimpson
Authors: Robinson William E. , Kustin Kenneth , Cloney Richard A.
Published: June 2005

Tunic in 46‐hr‐old Ascidia callosa larvae reared from dechorionated neurulae is either markedly reduced in thickness or absent altogether. The epidermis is fragile and cuticular fins fail to develop. Dechorionated neurulae treated with tunichrome and other reducing compounds (e.g., glutathione, ascorbate) show an enhancement in tunic formation and rudimentary fin development. UV absorbance spectra of extracts from unfertilized eggs, late tail‐bud embryos, and tadpole larvae indicate that tunichrome may be present in all developmental stages. Experiments with neurulae in which the chorion was punctured with tungsten needles but not removed signify that the test cells are the most likely source of tunichrome. Results are consistent with the hypothesis that tunichrome is involved in the natural processes of tunic morphogenesis in ascidian embryos.
Glycosaminoglycans stimulate the acrosome reaction of previously capacitated hamster sperm
Authors: Meizel Stanley , Turner Kenneth O.
Published: June 2005

The glycosaminoglycans (GAGs) hyaluronic acid and heparin were added (10 μg and 100 μg/ml to golden hamster sperm suspensions previously incubated for 4.5 h under capacitating conditions. After additions, sperm were incubated for 5–15 min and acrosome reactions (AR) assayed in motile sperm by phase contrast microscopy. Hyaluronic acid and heparin significantly stimulated AR over control levels. Hyaluronic acid did not stimulate AR 15 min after addition to sperm previously incubated for only 2.5 h. Pre‐incubation of hyaluronic acid with streptomyces hyaluronidase destroyed the ability of that GAG to stimulate the AR. These results indicate that GAGs (at least one of which, hyaluronic acid, is present in the oocyte cumulus oophorous) can rapidly stimulate the acrosome reaction in motile previously capacitated hamster sperm.
Urates and allantoic regulation in embryonic Japanese quail, Coturnix coturnix japonica
Authors: McNabb Roger A.
Published: June 2005

During embryonic development, allantoic fluid represents the shifting balance between renal excretion and reabsorption by chorioallantoic membranes. Allantoic contents of Na+, K+, Cl−, urate, pH, and water were followed over days 10–15 of the 16 day incubation. Water volume remained near 0.9 ml until day 13, then declined very rapidly. The pH declined more steadily, from 8 to 5.5. Contents of Na+ and Cl− fell regularly to final values 80–88% below day 10. The K+ content changed differently and nearly doubled by day 13 but returned to day 10 values at the end. Urate content rose until day 13, then fell suddenly to low levels. This was due to the abrupt precipitation of most urate into masses not sampled by our method, so that after day 13, urate was underestimated (probably by 90–96%). Ion binding by urates was low (about 3% of Na+ and Cl−, 10% of K+) and appeared to be nonspecific. The underestimate of urate contents means, however, that in late incubation about one third of allantoic Na+ and 65–70% of K+ and Cl− are bound to precipitated urate and do not appear in balance sheets of allantoic ions. These precipitated ions account for the significant amounts of Na+ and K+ that remain in the allantoic remnant, left in the eggshell after hatching, but whose presence is not predicted by analysis of allantoic fluid.
Matrix proteins of the teeth of the sea urchin Lytechinus variegatus
Authors: Veis Deborah J. , Albinger Todd M. , Clohisy John , Rahima Mohammed , Sabsay Boris , Veis Arthur
Published: June 2005

The teeth of the sea urchin Lytechinus variegatus grow continuously. The mineral phase, a high magnesium calcite, grows into single crystals within numerous compartments bounded by an organic matrix deposited by the odontoblasts. Electron microscopic examination of glutaraldehyde‐fixed Ethylene Diamine Tetra acetic acid (EDTA) demineralized teeth shows the compartment walls to be organized from multiple layers of cell membrane which might contain cytoplasmic protein inclusions. Proteins extracted during demineralization of unfixed teeth were examined by gel electrophoresis, high performance liquid chromatography, and amino acid analysis. The tooth proteins were acidic, they contained phosphoserine, and they were rich in aspartic acid. By contrast, the proteins of similarly extracted mineralized Aristotle's lantern skeletal elements were nonphosphorylated and were rich in glutamic acid. Vertebrate tooth and bone matrix proteins show similar differences. Surprisingly, an antibody to the principle rat incisor phosphoprotein showed a significant cross‐reactivity with the urchin tooth protein, by dot‐blot and enzyme‐linked immunosorbent assay procedures. Thus, the urchin tooth proteins contain epitope regions similar to those which are phenotypic markers of vertebrate odontoblasts. Whether this is an expression of convergent or divergent evolutionary processes, it is likely that the matrix proteins play a similar role in matrix mineralization. The sea urchin tooth may thus be an excellent model for the study of odontoblast‐mediated mineral–matrix relationships.
Experimental analysis of cytokinesis in Amoeba proteus
Authors: Rappaport R. , Rappaport Barbara N.
Published: June 2005

The purpose of this investigation was to determine whether the mechanism of cytokinesis in Amoeba proteus depends primarily upon locomotion and traction (fission) or whether the mechanism resembles that of metazoan cells. Cytokinesis is unaffected by measures that prevent attachment of the organism to the substratum. Amoebae divided when they were (1) detached from the substratum and repeatedly shifted, (2) suspended in fluid medium by one pole, (3) placed on an oil–water interface, and (4) transferred to de‐ionized water so that attachment was prevented. Unilateral furrows formed when the mitotic apparatus was shifted to an eccentric position. Enucleated portions of cytoplasm containing part of the equatorial region were amputated at different phases of the mitotic cycle. Enucleated pieces amputated at later prophase never formed permanent furrows, although 3 of 17 showed furrowlike activity. Of 26 enucleated pieces amputated at metaphase, 23 showed division activity. Of these, 21 formed temporary furrows and 2 completed division.

Although attachment and locomotion may be normal during division of A. proteus, they were not essential for cytokinesis, and their involvement is restricted to the final parting of the cytoplasmic thread that connects the daughter cells. The mechanism responsible for the greater part of the constriction activity in the furrow region resembles that of metazoan cells in that it is localized in the surface and it is established by the mitotic apparatus.
Development of the prepupal Verson's gland of the tobacco hornworm, Manduca sexta, and its hormonal control
Authors: Lane Sandra , Riddiford Lynn M. , Truman James W. , Conitz Jan
Published: June 2005

The segmentally arranged Verson's glands are epidermal derivatives comprised of three cells: the duct, saccule, and secretory cells. The development of these glands was followed through the 5th instar and larvalpupal transition of Manduca sexta. The glands are relatively small during the feeding stage, begin to grow at wandering, and undergo about a 50‐fold increase in size during the prepupal period. The increase in size is due mainly to the hypertrophy of the secretory cell which synthesizes a heterogeneous set of proteinaceous secretory products. Three prominent 11 to 12 kiloDalton (kD) polypeptides are made by the pharate fifth larval gland, whereas the pupal gland produces polypeptides ranging from 14 to 75 kD with a major complex at 30 to 34 kD. The secretory product is poured out onto the surface of the new cuticle at the time of ecdysis and contains all of the major proteins detected in extracts of the whole gland. The accumulation of secretory products by the gland occurs during the prepupal peak of ecdysteroid and is blocked if this rise is prevented by abdominal isolation. Infusion of 30 μg 20‐hydroxyecdysone (20‐HE) into such isolated abdomens caused synthesis of the pupal products. Treatment with the juvenile hormone mimic, methoprene, during the fifth instar showed that the commitment of the glands to produce the pupal proteins is independent of and occurs before the overlying epidermis becomes committed to make pupal cuticle.
Microcythemia from anemic hypoxia and normal erythropoiesis in the newt
Authors: Frangioni Giuliano , Borgioli Gianfranco , Martini Remo
Published: June 2005

Specimens of the newt, Triturus cristatus carnifex (Laurenti), rendered totally anemic, restore erythron by cyclic waves of erythropoietic activity that alternate with intervals of stasis. Hemolysis is obtained by administering 25 mg/liter of acetylphenylhydrazine in the breeding water for 36 h. The first cycle of erythropoietic activity produces microcytes, which have completely differentiated by 8 weeks after treatment. However, if the animals are raised in a hyperbaric chamber at a pressure of 1.5 atmospheres, in order to compensate for hypoxia, normocytes are produced. In both cases the hematocrit and hematic concentration of hemoglobin reach analogous values, so microcythemia appears to be the only effect of hypoxia. The hemoglobin, hematocrit values, and normocyte counts in hyperbaric animals are about onehalf those of the controls newts. These data, together with those on the life span of red blood cells (RBC) and time span between two successive erythropoietic cycles (2 months and 1 month, respectively), indicate that the newts normally keep only two sets (one new, one old) of RBC in circulation, whose approximate parameters can be defined as RBC count: 60,000/mm3, hematocrit: 17%, and hemoglobin: 5.4 g/100 ml.
Vitellogenin in the camel cricket Ceuthophilus sp. (orthoptera, gryllacrididae)
Authors: Bradley James T. , Kerle Karen Koon , Wolfe Karen G.
Published: June 2005

Hemolymph and egg yolk proteins in the camel cricket, Ceuthophilus sp., were analyzed by native and SDS‐polyacrylamide gel electrophoresis. Four sex‐specific polypeptides (FSYPs I–IV) accounted for 44% of the hemolymph protein in adult females. These polypeptides were absent from the blood of adult males and female nymphs but composed 63% of the yolk protein in fully grown oocytes. Hemolymph FSYPs became labeled with [35S]‐methionine after a 1‐hour period of in vivo incorporation and appeared in terminal, vitellogenic follicles after 2 hours of incorporation. Two‐dimensional gel electrophoresis showed that all four FSYPs occur in a single egg‐yolk glycoprotein also present in adult female hemolymph. We conclude that this glycoprotein is a multisubunit vitellogenin (VG). Two high molecular weight polypeptides synthesized by the fat body of adult females and immunoreactive with VG‐specific antiserum were tentatively identified as proVGs.
Renal and hormonal responses to atrial natriuretic peptide and turtle atrial extract in the freshwater turtle, Amyda japonica
Authors: Cho Kyung Woo , Kim Suhn Hee , Koh Gou Young , Seul Kyung Hwan
Published: June 2005

The effects of synthetic atrial natriuretic peptide and turtle atrial extract on cardiovascular and renal functions were examined in the freshwater turtle, Amyda japonica.

Both the atrium and ventricle of the turtle heart contained an immunoreactive atrial natriuretic peptide. Synthetic rat atrial natriuretic peptide (atriopeptin III) and turtle atrial extract caused a dose‐dependent decrease in mean arterial blood pressure. In turtles that received either atriopeptin III or turtle atrial extract, no significant changes in renal function were observed. However, furosemide was effective in altering renal function. Levels of aldosterone in plasma decreased after 2 hours and increased after 24 hours following injection of atriopeptin III, although the plasma renin concentration did not change.

We suggest that the heart of the freshwater turtle may contain an immunoreactive atrial natriuretic peptide and that the atrial natriuretic peptide is more important in the regulation of blood pressure than in the regulation of renal function.
Quantitative studies on variation in sperm head morphology of the hopping mouse, Notomys alexis
Authors: Suttle J. M. , Moore H. D. M. , Peirce E. J. , Breed W. G.
Published: June 2005

Spermatozoa from the Australian conilurine rodent, Notomys alexis, display a remarkable degree of variability in head morphology. This variation was quantified by differential counting (n=18 animals) and image analysis (n=4 animals) of spermatozoa recovered from the cauda epididymidis and vasa deferentia. Variability in sperm morphology was exhibited in all individuals examined regardless of age. Sperm heads examined by phase contrast microscopy could be classified into four main types, and in addition, often bizarre forms occurred that ranged in shape from having a small dorsocaudal projection to being ovoid or dome‐shaped. Measured by image analysis, sperm nuclear size for Notomys alexis ranged from 2.21 to 6.94 μm2 (mean 4.34 ± 0.94 μm2) as compared with a range of 4.53–5.82 μm2 (mean 5.33 ± 0.26 μm2) for spermatozoa from Pseudomys australis, a closely related species. The acrosome of Notomys alexis spermatozoa also exhibited considerable morphological variation as detected by immunolocalisation with a monoclonal antibody to a mammalian acrosomal antigen.

This variability exhibited by both the acrosome and the nucleus of the sperm head in Notomys alexis may relate to low levels of intermale sperm competition that probably occurs in these animals.