bluuebunny/crossref_metadata_2025 huggingface dataset:
Post‐exercise acid‐base balance and ventilatory control in Birgus latro, the coconut crab
Authors: Smatresk N. J. , Cameron J. N.
Published: June 2005

There is a postexercise acidosis in the coconut crab, Birgus latro, which is initially due to an elevation in the hemolymph P, and a metabolic acidosis which is only partially due to lactic acid. Hyperventilation following exercise causes a respiratory alkalosis that helps to restore acid‐base balance. The ventilatory receptors appear to be internally located, and ventilation is stimulated by a drop in the hemolymph pH or [HCO], but not by P or P. Amelioration of the metabolic acidosis in normal crabs occurs in 1 hour despite elevated lactate levels. Crabs with their gills removed showed only a transient lag in both respiratory and metabolic recovery from acidosis, indicating the dominance of the branchial lung of Birgus in gas exchange. The data suggest that intra‐ and extracellular transfers may be significant in acid‐base regulation.
A survey of blood and tissue nitrogen compounds in terrestrial decapods of Palau
Authors: Henry Raymond P. , Cameron James N.
Published: June 2005

Terrestrial decapods have significant levels of ammonia, uric acid and free amino acids in their blood, but blood is hypo‐osmotic to local seawater by as much as 300 mOsm/kg. Blood water content is approximately 90%, with protein making up virtually all the difference, whereas tissue water is between 70% and 80%. The tissue free amino acid pool is composed primarily of glycine, serine, proline, alanine and arginine, which are typical of all crustaceans. The size of the muscle pool is reduced in comparison to aquatic species, while that of gill is comparable. Tissue ammonia levels are very low in comparison to FAA, but these levels are significantly higher in gill than in muscle.
Maintenance of mating reactivity and capacity of transferring meiotic induction by an activated to a homotypically united cell in Blepharisma
Authors: Santangelo Giovanni , Nobili Renzo
Published: June 2005

The two complementary mating types of Blepharisma japonicum, I and II, undergo cell pairing if activated by the complementary gamones. Pairs form in three possible combinations: I–I, II–II, I–II. In the two former unions (homotypic pairs), no nuclear changes occur in the cells. In the third union (heterotypic pairs), a diffusible factor produced during the first 2 hours of cell contact is assumed to induce meiosis and other nuclear changes in the cells. When cells were surgically separated during the first 2 hours after the onset of pairing, the behavior of cells from heterotypic pairs with respect to the occurrence of meiosis was alike in 93% of the cases. Cells of heterotypic pairs, separated from 0.66 to 2.66 hours after mixing complementary mating types, can homotypically reunite with gamone‐activated cells of their own mating type. The capacity of separated cells to reunite decreases as the time of heterotypic union increases. In 32 cases out of 80, separated cells whose partner underwent meiosis reunited, and three of them were able to induce macronuclear changes correlated to meiosis in the homotypically united cells.
A note on the inhibition of in vitro meiotic maturation of mammalian oocytes by dibutyryl cyclic AMP
Authors: Jagiello Georgiana , Ducayen Mercedes B. , Goonan William D.
Published: June 2005

Cytogenetic data are presented which indicate species differences in the response of oocytes maturing in vitro in the presence of dibutyryl cyclic AMP (dbcAMP). Inhibition of ewe oocyte maturation was noted at germinal vesicle, MI, and MII in the presence of 25–750 μg/ml of dbcAMP. Cow oocytes were primarily affected at MI and MII by similar concentrations, and only 750 μg/ml delayed golden hamster oocytes at these stages. These findings highlight the variability between the responses of the oocytes of these mammals and the rat, mouse, or pig.
Western fence lizard (Sceloporus occidentalis) chemical signals. II. A replication with naturally breeding adults and a test of the cowles and phelan hypothesis of rattlesnake olfaction
Authors: Duvall David
Published: June 2005

The capacity of naturally breeding western fence lizards (Sceloporus occidentalis biseriatus) to discriminate and respond to conspecific and control chemical cues was examined. Lizards were presented with markings and exudates of male and female donors, as well as cologne (a pungency control) and water, in a successive discrimination procedure. Behavioral actions quantified after exposure to the different chemical cue types included lingual extrusions (tongue flicks and substrate licks), rapid nasal inhalations, and the performance of push‐up visual displays. Initial latencies to lingual investigation of the different extracts and markings also were recorded as a measure of the extent to which nasal olfaction would switch on the tongue‐Jacobson's organ (vomeronasal olfactory) system. Although no sex differences in total levels of response were noted, males and females exhibited significant lingual discriminations equally to exudates collected from male or female conspecifics. Push‐up visual displays also were noted in response to conspecific markings. Cologne‐marked surfaces, however, elicited nonsignificant levels of lingual investigation and push‐up displaying. Latencies to initial tongue flicks, but not substrate licks, were significantly shorter when any material other than water was present. Therefore, as suggested by Cowles and Phelan ('58), nasal olfaction may indeed be more of a “quantitative,” distance sensing system that responds to the presence of any pungent substance by initiating further investigation via the tongue‐Jacobson's organ system. The latter appears to be more “qualitative,” or discriminating, as indexed by relatively greater levels of lingual investigation of conspecific markings than cologne. No differences were noted in rapid nasal inhalation activity. The results suggest that pheromone markings, along the ground or other surfaces, may be important to spacing and territorial maintenance in nature. This could occur through direct pheromone effects on signal recipients, or indirectly, through the stimulation of increased push‐up activity, which could make lizards more visible to one another.
Correlation of juvenile hormone titer changes with reproductive tract development in the posteclosion Monarch butterfly
Authors: Herman W. S. , Lessman C. A. , Johnson G. D.
Published: June 2005

The posteclosion growth of the reproductive tracts of male and female Monarch (Danaus plexippus) butterflies was quantified over a 30‐day period of storage in summer conditions. Concomitantly, the Galleria bioassay was used to quantify hemolymph juvenile hormone (JH) titers in both sexes. The data demonstrated rapid posteclosion growth, lasting for about one week, of the female ovaries and colleterial glands and the male accessory glands, tubular glands, and ejaculatory ducts. This rapid growth was not directly related to increased animal weight, but it was associated with high JH titers. The highest titers observed were found in females on the third day after eclosion. Subsequently, most of the above organs exhibited a reduced growth rate that appeared to depend upon increased body weight. Butterflies examined during this latter stage (from about 8‐30 days posteclosion) exhibited significant reductions of hemolymph JH. JH injections into both sexes showed that most organs known to be JH‐sensitive retained hormone sensitivity during the period of reduced growth. The growth of female receptacle glands and bursa copulatrix and the male testes and seminal vesicle‐vas deferens complex was not directly comparable to those organs discussed above.
The role of calcium in maintaining motility in mouse spermatozoa
Authors: Heffner Linda J. , Storey Bayard T.
Published: June 2005

Maintenance of mouse sperm motility requires exogenous Ca+2 in most, but not all, samples of epididymal spermatozoa. In these samples, the loss of motility with time is the same in Tris/NaCl buffer containing 1.7 mM Ca+2 (medium TNC) as it is in complete culture medium used for in vitro fertilization (medium CM) over the first 2 hours; spermatozoa in medium TNC lose motility at more rapid rate thereafter. The cation specificity for maintenance of motility is unusual in that both Sr+2 and Mg+2 substitute for Ca+2, with Mg+2 being the more effective. In the absence of Ca+2, these samples of mouse epididymal spermatozoa in Tris/NaCl buffer (medium TN) lose motility in about 30 minutes. If Ca+2 is added after incubation in TN for 15 minutes, motility is maintained as well as it is in medium TNC. If Ca+2 is added at 30 minutes, motility is partially restored. But if Ca+2 is added after 60 minutes, there is no restoration of motility. Spermatozoa suspended in medium TNC lose motility rapidly on addition of EGTA in excess of the Ca+2 present. Attempts to show uptake of Ca+2 by spectrophotometric assay, by effects of Ca+2 on oxidative metabolism, and by electron probe X‐ray microanalysis were unsucessful; motility is not maintained by entry of Ca+2 into the cells. Our results are consistent with a Ca+2 site on the plasma membrane and suggest that these sites function as oligomers of ordered subunits whose structure requires Ca+2. In the absence of Ca+2, the ability to form the oligomer is lost with time, possibly due to an irreversible conformational change.
Metabolic responses of striped bass (Morone saxatilis) to temperature acclimation. II. Alterations in metabolic carbon sources and distributions of fiber types in locomotory muscle
Authors: Jones Peter L. , Sidell Bruce D.
Published: June 2005

The effects of temperature acclimation on (1) fiber‐type distribution, and (2) alternate metabolic fuels for energy supply within different skeletal muscle fiber types in striped bass (Morone saxatilis) were examined. Histochemical analysis demonstrated an increase in the proportional cross sectional area of oxidative red fibers from 9.03% to 15.03% during cold acclimation (25°‐5°C). The rate of oxygen consumption was 1.78 times greater in red muscle than white in 25°C acclimated fish. This ratio increased to 2.32 in 5° fish. Oxidation of both 14C‐U‐glucose and 14C‐1‐palmitate was significantly greater in red muscle than in white at both acclimation temperatures. A lack of thermal compensation for metabolism of 14C‐U‐glucose was exhibited by both fiber types. Red muscle showed a dramatic increase in rate of 14C‐1‐palmitate oxidation after cold acclimation. Activities of glycolytic enzymes confirmed a high glycolytic capacity in white muscle; glycolytic capacities were dependent on acclimation temperature in both fiber types. Only red muscle showed a positive compensation for activities of key enzymes from aerobic metabolism. The results indicate an increasing reliance on aerobic metabolism of fat in the swimming musculature at cold acclimation temperatures. The capacity for sustained swimming under these conditions is conserved by (1) an increase in the relative proportion of red fibers, and (2) an enhanced capacity for energy supply in the red muscle by oxidative metabolism of stored lipid.
The role of the blood in the temperature dependence of oxidative metabolism in decapod crustaceans. II. Interspecific adaptations to latitudinal changes
Authors: Mauro Nicholas A. , Mangum Charlotte P.
Published: June 2005

The effects of acclimation temperature on hemocyanin‐oxygen (HcO2) transport were examined in two species of decapod crustaceans representing different geographic and thermal ranges. In the coldwater species Cancer borealis and the warmwater species Menippe mercenaria, the performance of the HcO2 transport system is maximized at 15 °C, a summer temperature in the northern habitat and a winter temperature in the southern habitat. In C. borealis little unloading at the tissues occurs at 5 °C, and in M. mercenaria oxygenation at the gill is incomplete at 25 °C. The temperature coefficients describing rates of ventilation, heartbeat, and total oxidative metabolism fall within a narrow range (Q10 = 1.9−3.6), providing no indication of ventilatory or cardiovascular adjustments that would allow the HcO2 transport system to function at the maximum level at different temperatures. Comparison of the HcO2 equilibrium properties suggests that HcO2 affinity has been selected for a particular thermal range, but not cooperativity or pH dependence. The thermal limits of the O2 transport system are set by both the direct effect of temperature on HcO2 equilibrium and the indirect effect via the Bohr shift that accompanies the change in blood pH with temperature.
Experimental studies of the origin and expression of metameric pattern in the chick embryo
Authors: Meier Stephen , Jacobson Antone G.
Published: June 2005

On either side of Hensen's node of the fully extended primitive streak of the chick embryo (stage 4) the mesoderm is already organized into circular domains called somitomeres. As Hensen's node regresses, paraxial somitomeres are added in tandem and are early morphological representatives of metameric pattern in the mesoderm. These organized circular domains of mesenchyme cells are best visualized with stereo pair scanning electron microscopy. Experiments suggested that a prepattern of segmentation exists in and around the fully extended primitive streak. Streaks divested of Hensen's node can generate some paraxial somites, but only if surgically split down the midline. We assessed metameric pattern formation in nodeless streaks, both severed and unsevered down the midline. Operated blastoderms were cultured 15 hours, fixed, dissected, processed for scanning electron microscopy, and photographed in stereo. Split nodeless streaks produced a cranial to caudal sequence of somitomeric development. This sequence is similar to the sequential maturational events seen in the segmental plate of older embryos. The least mature somitomeres, toward the posterior end of the severed edge, appear as circular domains of radially oriented cells, looking much like the first somitomeres to emerge near Hensen's node of the stage 4 streak. More cranially along the severed edge, somitomeres are morphologically more mature, being more condensed, with cells oriented about a central myocoele. At the most cranial end of the severed piece, somitomeres are the most mature, having contracted about their centers to create intersomitomeric gaps that permit their identification with light microscopy as individual “somites.” Embryos from which the node was removed, but the streak left intact, generated only the most primitive somitomeric pattern repetitively along either side of the primitive groove. We conclude that regression of Hensen's node provides for the timely initiation of morphogenesis of somitomeres from a prepattern of segmentation that already exists.
Adaptive lung growth during chronic cold plus hypoxia is age‐dependent
Authors: Lechner Andrew J. , Grimes Margaret J. , Aquin Lynn , Banchero Natalio
Published: June 2005

Wealing male guinea pigs (Cavia porcellus) of initial body weight 207–271 g and 2–3 weeks of age were exposed for up to 16 weeks to combined cold (Ta = 6°C) and hypoxia (ambinet P = 85 torr) before analysis (range of body weights at sacrifice, 253–932 g). The body growth rate of the cold + hypoxia guinea pigs was not different from that of the control animals raised at Ta = 22°C and an ambient P = 133 torr. After 3 weeks of cold + hypoxia exposure, and a mean body weight of 402 g, the weight‐specifi lung volume, VL, of 3.59 ± 0.29 ml/100 g BW (mean ± SEM) in cold + hypoxia was significantly greater than the value of 2.65 ± 0.16 for age‐ and weight‐matched controls. However, by week 16 of exposure, there wer no significant differences in VL betweent he experimentals (2.24 ± 0.08) and the controls (2.04 ± 0.15). Similar relationships were found between the two groups for weight‐specific alveolar epithelial and capillary endothelial surface areas. Although chronic exposure to both increased oxidative demand and reduced oxygen availability trasiently increased the pulmonary dimensions suitable for gas exchange, normal adult dimensions were ultimately achieved. Furthermore, the similarity of lung growth in cold plus hypoxia to the patterns reported for exposure to cold or hypoxia alone suggests a common and rather nonspecific response mechanism for such adaptive growth in the lung.
Isolation and separation of cells from the digestive gland epithelium of Busycon canaliculatum
Authors: Cornell‐Bell A. H. , Munro D. R.
Published: June 2005

A structural analysis of the intact digestive gland epithelium of Busycon canaliculatum was undertaken at the light and ultrastructual levels. Procedures were developed for the isolation and separation of component epithelial cells by modifying existing pronase digestion techniques. Three distinct cell types were identified following separation by velocity sedimentation. Cells identified after isolation, and separation can be related to the intact digestive gland epithelium.
Mechanisms of G6PD isozyme pattern changes at fertilization
Authors: Barber Mary Lee , Kolan David M. , Yabuta Craig , Nielsen Blake
Published: June 2005

The electrophoretic pattern of G6PD changes in sea urchin egg supernatants, gels, and pellets (homogenized in 0.01 M MgCl2, 0.01 M Tris, pH 8, and centrifuged at 4 × 104g) within the first minute following sperm penetration. Therefore, the changes in pattern are an early event of egg activation and are not changes in gene activity. Calcium ionophore activation causes similar changes in G6PD in unfertilized eggs, so calcium is probably involved directly or indirectly. Treatment with 1 mg/ml of G6P and/or NADP, DTT, or papain also causes changes in the isozyme patterns, but the resulting patterns are different from patterns obtained from the fertilized fractions, and each treatment produces a unique pattern. The results lead to the conclusion that the different patterns of unfertilized and fertilized eggs are due to enzyme posttranslational modification. Different patterns may result from intrinsic differences in (1) —SH reduction or levels of glutathione, (2) substrate and cofactor levels, or (3) proteolytic enzymes released naturally or as a result of homogenization.
Low water vapor conductance of hard‐shelled eggs of the gecko lizards Hemidactylus and Lepidodactylus
Authors: Dunson William A.
Published: June 2005

Typical reptilian eggs require a moist substrate for normal development and undergo a water loss across the shell in dry air many times that of avian eggs. Certain geckos lay hard‐shelled, calcareous eggs, often in arboreal locations, that have been postulated to be truly cleidoic. It has been demonstrated here for the first time that such hard‐shelled gecko eggs do in fact have extremely low rates of evaporative water loss in dry air. Indeed, values of water vapor conductance are considerably lower than those predicted for avian eggs of the same mass. Normal embryonic development apparently does not require absorption of liquid water from the environment. It is quite likely that these geckos represent an independent evolution of the cleidoic egg, separate from the reptilian lineage that led to the birds.
Purification and composition of protein antifreezes with high cysteine contents from larvae of the beetle, Tenebrio molitor
Authors: Patterson Jean L. , Duman John G.
Published: June 2005

Two antifreeze proteins with thermal hysteresis activity (they depress the freezing point of aqueous solutions by a noncolligative mechanism well below the melting point) were purified from cold‐acclimated larvae of the beetle, Tenebrio molitor. Both proteins have unusual amino acid compositions consisting of high levels of cysteine (15.4 and 28.0 mol%).
insect vitellins: Identification, purification, and characterization from eight orders
Authors: Harnish Delsworth G. , White Bradley N.
Published: June 2005

Vitellins were identified, purified, and analyzed from insects representing eight orders. The structures and polypeptide constituents of vitellins of Hyalophora cecropia, Tenebrio molitor, Rhodnius prolixus, Forficula auricularia, Periplaneta americana, and a mayfly were found to have common features. The native proteins had Mr of 385,000–470,000 (385–470 K) and were composed of high (100–180 K) and low (47–84 K) molecular weight polypeptides in equimolar proportions. The vitellins of Apis mellifera, a sphecid wasp, and Aedes aegypti, however, had lower Mr (200–350 K) and were composed of only large polypeptides (170–190 K). The higher Diptera form a distinct third group with vitellins made up entirely of small polypeptides of about 50 K.
Insect vitellins: Identification of primary products of translation
Authors: Harnish Delsworth G. , Wyatt G. R. , White Bradley N.
Published: June 2005

The primary products of translation of the vitellins of Hyalophora cecropia, Tenebrio molitor, and Aedes aegypti were identified by pulse‐chase labeling in fat body incubated in vitro, specific antisera being used to identify the immunospecific products. The vitellogenin of H. cecropia was found to be synthesized as a polypeptide of 220,000 daltons (220 K), which was cleaved to yield two polypeptides of 180 K and 47 K. The immunoprecipitable polypeptides secreted into the media during a 3‐hour culture were also 180 K and 47 K. The vitellogenin of T. molitor was synthesized as 204 K primary translation products, which were cleaved to yield polypeptides of 160 K, 56 K, and 45 K. A. aegypti vitellogenin differed from those H. cecropia and T. molitor in that the protein was synthesized as two closely migrating polypeptides of about 170 K, which were not cleaved prior to secretion. RNA from blood‐fed female A. aegypti directed the synthesis of polypeptides, in the rabbit reticulocyte cell‐free protein synthesizing system, which were of similar weight to the vitellin polypeptides. These results, taken together with data published elsewhere on certain higher Diptera, support the division of insect vitellins into three broad structural groups, as already proposed (Harnish and White, 1982).
Cytodifferentiation in the accessory glands of Tenebrio molitor. VII. Patterns of leucine incorporation by the bean‐shaped glands of males
Authors: Happ George M. , Yuncker Christine , Dailey Patrick J.
Published: June 2005

The bean‐shaped accessory glands of male mealworm beetles are morphologically complex. Seven distinct cell types produce a semisolid secretory mass that contains structural proteins of the spermatophore. Cell numbers increase 3.5‐fold over the pupal instar, and gland volume increases 30‐fold over the pupal and early adult stage. DNA content reaches its maximum at adult ecdysis (11 pg/secretory cell), RNA at 4 days later (55 pg/cell), and protein at 6 days after ecdysis (1,200 pg/cell). Rates of 14C‐ and 3H‐leucine incroporation increase in parallel to the rise in protein content. Over ten putative secretory protein bands were identified by using one‐dimensional SDS‐slab gel electrophoresis to compare BAG homogenates with homogenates of the secretory mass and the spermatophore. At least five of these secretory proteins accumulate in BAGs after adult ecdysis, and most show high rates of leucine incorporation in the adult. Twodimensional gel electrophoresis (pI and SDS) and fluorography allowed us to identify a score of reference spots, at least seven spots that are characteristic of the pupa, and over 40 spots that appear to be differentiation‐specific and are presumably secretory products. The fluorographic indices give an unambiguous means of scoring terminal differentiation in the BAG.
Preconjugant cell interaction in Euplotes crassus: An analysis by temporary cycloheximide treatments
Authors: Dini F. , Miyake A.
Published: June 2005

Conjugation in ciliates is induced by the interaction between preconjugant cells of complementary mating types. We investigated this interaction in Euplotes crassus by inserting a temporary treatment of 10 μg/ml cycloheximide before and during the interaction. This agent effectively inhibits protein synthesis and reversibly inhibits conjugation in this species. Our results indicate that 1) preconjugants of each mating type have a type‐specific protein factor for the interaction; 2) the factor is in a state of equilibrium of turnover and synthesis; 3) interaction by these factors induces a higher production of the same factors; 4) at the beginning of this interaction, a nonprotein factor, which participates in the preconjugant interaction in a still unspecified way, is produced; and 5) the interaction also transforms the cell surface so that cells can unite in conjugant pairs. Preconjugant interaction of E. crassus is, therefore, very similar to that of Paramecium in spite of the behavioral differences during preconjugant interaction—for example, presence (E. crassus) versus absence (Paramecium) of the waiting period. This investigation also supports the positive feedback hypothesis of the mating reaction by Heckmann and Siegel ('64). Our finding of the new reaction at the beginning of the interaction might provide a new clue for the analysis of preconjugant interaction in ciliates.
Enzymatic correlates and ontogeny of uricotelism in tree frogs of the genus Phyllomedusa
Authors: Shoemaker Vaughan H. , McClanahan Lon L.
Published: June 2005

Activities of arginase, xanthine dehydrogenase, and uricase were measured in liver and kidney of adult Phyllomedusa sauvagei and P. hypochondrialis to examine the enzymatic basis of their unusual ability to excrete uric acid. Comparable values were obtained for two species of ureotelic anurans and a uricotelic lizard. Both Phyllomedusa species exhibited high hepatic and renal levels of xanthine dehydrogenase, whereas this enzyme was not detected in the livers of the ureotelic frogs or the lizard. Hepatic xanthine dehydrogenase was significantly higher in P. sauvagei, which excretes urate predominantly, than in P. hypochondrialis, which excretes 20% of its nitrogen as urate. Hepatic arginase was much lower in both Phyllomedusa species than in the ureotelic frogs, but higher than in the lizard. Reduced levels of uricase were also associated with uricotelism in this genus.

Xanthine dehydrogenase was present in livers of larval P. sauvagei well in advance of the onset of uric acid excretion late in metamorphosis. Premetamorphic larvae excreted over 50% of their nitrogen waste as urea and the balance as ammonia.
Morphological analysis of the development of the primary organizer in avian embryos
Authors: Triplett Ronald L. , Meier Stephen
Published: June 2005

Scanning electron microscopic (SEM) analysis of the primary organizer region of the mesoblast of avian embryos, stages 3–5, showed that mesodermal cells gastrulated through the primitive streak are organized into distinct domains as early as stage 3. These domains initiate a metameric pattern consisting of prechordal plate and the first pair of somitomeres. The prechordal plate first appears immediately anterior to the primitive streak, along the embryonic midline, whereas the somitomeres are located on either side of the prechordal plate in the paraxial mesoblast region. The appearance of a metameric pattern during mesoblast expansion preceeds the formation of Hensen's node and full elongation of the primitive streak. By stage 4 of development the primitive streak is fully elongated, and Hensen's node is established as a raised hillock of epiblast at the cranialmost end of the axis. Also at this stage, avian embryos show the first indication of notochord formation. The notochord initially appears as a highly condensed, elliptical domain of concentrically organized chordamesoblast cells (100μm in length), deposited along the midline between the prechordal plate and Hensen's node (the source of chorda cells). This initial group of notochord cells has been termed a notochord segment. Continued regression of Hensen's node along the primitive streak results in the sequential generation of paraxial somitomeres and axial notochord segments, each segment measuring approximately 100 μm in length. By stage 5, the avian embryonic axis contains four pairs of somitomeres and four axial notochordal segments.
Intercalary and supernumerary regeneration in limbs of stages of the Egyptian toad, Bufo regularis Reuss
Authors: Michael Milad I. , Hassona Abdulla A.
Published: June 2005

Intercalary regeneration in the hind limbs of four larval stages of Bufo regularis Reuss (numbers 53, 54, 55, 56) was studied by either removal of the thigh region or removal of the shank and base of ankle region. No intercalary thigh regeneration had taken place in any of these stages. However, intercalary regeneration of the shank/ankle region took place in 52% of the cases of stage 53, in 40% of the cases of stage 54, in 22% of the cases of stage 55, but in none of the cases of stage 56. The intercalated skeleton, particularly that of the ankle, showed deformity in its organization by stage 55. Histologically, in a time series of cases fixed between the first and fifteenth postoperative days, mesenchyme cells began to accumulate and to intervene between the stump and graft tissues around the sixth day, in positive cases. The origin of these cells from stump or/and graft tissues could not be ascertained. Supernumeraries appeared close to the transplantation sites, of both levels, in the operated cases of three stages but not in the case of stage 56. Their incidence faded proximodistally, being lower at the thigh level than at the shank/ankle level. When two or more supernumeraries appeared in one case, they were oriented, according to their toes' arrangement, as mirror images to each other and relative to the graft itself, following Bateson's rule. We conclude that intercalary and supernumerary regeneration may be parallel to the normal regeneration events, since all are governed by the level of transplantation or transection and the grade of differentiation of the limb tissues at that level.
Macrocyst formation in Dictyostelium discoideum: Mating or selfing?
Authors: Bozzone Donna M. , Bonner John T.
Published: June 2005

It is known from previous work that macrocysts are formed when the two strains of Dictyostelium discoideum (NC4 and V12) are mixed. By culturing NC4 and V12 amoebae together in various ratios and at several densities, and in experiments using vitally stained cells, we have shown that the number of macrocysts formed is directly related to the number of V 12 (but not NC4) cells present and that macrocysts may occur without sexual fusion.
Relationships between size of hypostome and number of tentacles in hydra
Authors: O'hern Jennie , Lenhoff Howard M.
Published: June 2005

Plots of the circumference of the hypostome of hydra against the number of tentacles surrounding each hypostome gave a linear relationship. The slope of the line is a characteristic of each species and strain of hydra studied and represents the amount of the circumference of the hypostome relegated to each tentacle. We interpret the intercept on the ordinate of such plots to represent the minimum amount of tissue needed, expressed as circumference of that hypostome, before a first tentacle can form. Hypostomes of newly dropped buds have about the same circumferences as those of adult animals. Diagrams of spacing patterns of tentacles from different species illustrate that the larger the animal, the greater the space between the tentacles. Intertentacular space occupies from 22 to 37% of the hypostome circumferences. The relationship between the average size of the hypostome for a number of groups of hydra and the average size of an animal (measured in micrograms of protein per animal) shows that the size of the hypostome is proportional to the size of the group of hydra being measured, with larger species of hydra having larger hypostomes until a maximum size is reached. We noticed a similar relationship between the part of the circumference of the hypostome occupied to each tentacle vs. animal size. Apparently more hypostomal tissue is allotted to each tentacle in specimens of larger species than to those of smaller ones, and the amount of hypostomal tissue per tentacle reaches a limit regardless of the size of the species.
Blastocyst protein synthesis during obligate delay of implantation and embryo activation in the western spotted skunk
Authors: Rourke A. W. , Mead Rodney A.
Published: June 2005

The in utero protein synthetic activity of embryos of the western spotted skunk has been examined by one‐dimensional gel electrophoresis and fluorography. The results indicate that delayed‐implanting embryos synthesize a large variety of proteins with molecular weights from < 15,000 to > 200,000. Delayed‐implanting blastocysts synthesize several very large proteinaceous molecules which do not appear to be produced by activated, preimplantation embryos. Activated embryos show increased synthetic activity, but there are many qualitative similarities in the molecular weight profiles characteristic of delay and activated blastocysts.
Ultrastructure of the body‐wall muscle of the ascidian Halocynthia roretzi: Smooth muscle cell with multiple nuclei
Authors: Shinohara Yoshiko , Konishi Kazuhiko
Published: June 2005

The structure of the body‐wall muscle of the ascidian, Halocynthia roretzi, was investigated by electron and light microscopy. Thin (about 8 nm in diameter), (18–20 nm in diameter), and 10‐nm filaments were seen in this muscle cell. These filaments, however, did not have the regular arrangement of a striated or oblique structure. We also found by three‐dimensional reconstruction that this muscle cell is multinucleated. Based on these observations, we report that the body‐wall muscle of the ascidian, Halocynthia roretzi, is smooth and multinucleated.
Influence of vasopressin and oxytocin on neoteny in the adult mexican axolotl Ambystoma mexicanum
Authors: Wells Dan E. , Moser Charles R.
Published: June 2005

Lysine‐vasopressin and oxytocin were tested on the normally neotenous adult Mexican axolotl, Ambystoma mexicanum, to determine their influence on metamorphosis. The salamanders were divided into four groups, and daily injections of saline, lysine‐vasopressin, oxytocin, and TSH were made over a 28‐day test period. Tail height, gill length, and body weight were measured as indicators of metamorphic change. Additionally, thyroid uptake of 131I was determined.

The results showed that the vasopressin and oxytocin groups had a significant (P < 0.01) loss in tail height and body weight compared to controls, but showed no gill rachis resorption or 131I uptake. These results suggest that the effects of vasopressin and oxytocin were not mediated by TSH and thyroxine, but rather may be caused by an antagonism of prolactin.
Bioelectric activity in the rabbit ear regeneration
Authors: Chang K. S. , Snellen J. W.
Published: June 2005

A 1‐cm‐diameter hole was punched through rabbits' ears. The surface potentials during wound healing of regenerating (normal) and partially and nonregenerating (decartilaged) ears were measured. The time sequence of these surface potentials were similar to those reported to occur in regenerating amphibians forelimbs. A small positive potential was observed for about 1 week, and this was followed by a larger negative potential of up to 20 mV, with different durations. The duration of the positive potential was about the same as which was observed in amphibians. The duration and the amplitude of the negative potential were greatest for completely regenerating ears with overgrowth, smaller for partially regenerating ears, and smallest for the nonregenerating ears. The surface potential was localized. If a nipple‐shaped outgrowth developed after the hole was closed, the surface potential was observed only on this outgrowth; immediately outside it, the potential was normal. We concluded that the negative bioelectric activity accompanies growth, and while growth continues, negative bioelectric potential continues.
Differential proliferation in morphogenesis of lateral body folds
Authors: Miller S. A.
Published: June 2005

Morphometric analysis and thymidine autoradiography were used to test the hypothesis that differential growth in the form of proliferative asymmetry is a major contributor to formation of lateral body folds in somatopleure. Chick embryos provided an opportunity to study both spatial and temporal differentials within an individual stage of development. Ectoderm and mesoderm were studied as separated tissues. Thymidine labeling index ranged from 34% to 49% in ectoderm and 43% to 66% in mesoderm and was assumed to reflect rate of proliferation in populations with a 100% proliferation index. Density of cell ranged from ten to 13 cells/1,000 μm2 in ectoderm and ten to 15 cells/1,000 μm2 in mesoderm, with a mean density of 12 cells/1,000 μm2. Cellular proliferation was important in folding, because ectoderm showed highest frequencies of labeling and highest cell density in folding levels. Correlation of proliferative differentials with morphogenesis suggests that proliferation is the form of growth contributing to formation of lateral body folds in 20‐somite chick embryos.
An ultrastructural‐histochemical dichotomy in crayfish muscle
Authors: Crabtree R. L. , Tse Fred
Published: June 2005

Histochemical staining of the promotor muscles in the crayfish indicates that ATPase activities are not differentiated between the short sarcomere fibers of the lateral head and many long sarcomere fibers of the anterior head.
The distribution and partial characterization of carbonic anhydrase in selected aquatic and terrestrial decapod crustaceans
Authors: Henry Raymond P. , Cameron James N.
Published: June 2005

A sensitive pH‐stat assay was used to determine the distribution in aquatic and terrestrial decapod crustaceans, correlation to osmoregulation, and selected kinetic properties of carbonic anhydrase. In all species the enzyme was concentrated in the gills, and specifically the posterior three or four gill pairs. Activity was highest in the gills of osmoregulating species, and the enzyme could be localized in the areas of the gill lamellae which contained a high density of salt absorbing cells. The enzyme from the blue crab, Callinectes sapidus, exhibits a number of characteristics remarkably similar to the Na+/K+ ATPase from that species. Both enzymes show the same inter‐ and intrabrachial distribution and the same reactions to altered environmental salinity. Branchial CA from both species was inhibited by high concentrations of NaCl and increasing pH. The enzyme showed a temperature optimum of 25°C. On the basis of these initial results, it appears that crustacean gill carbonic anhydrase plays an important role in the blood osmoregulatory process.
Cytokinesis: The effect of initial distance between mitotic apparatus and surface on the rate of subsequent cleavage furrow progress
Authors: Rappaport R.
Published: June 2005

The purpose of this investigation was to determine whether furrows which develop in surfaces distant from the mitotic apparatus function at the same rate as those which develop in surfaces close to the mitotic apparatus. Fertilized, denuded Echinarachnius parma eggs were flattened to a diameter of 175 μm and a thickness of 60 μm 30 to 45 minutes before cleavage in such a way that the mitotic apparatus was eccentric. The initial distance between the mitotic apparatus and the equatorial margin before furrowing was determined as well as the rates of progress of the furrows formed in the opposite margins. The mean rate of progress of furrows which develop in margins 100 to 110 μm from the mitotic apparatus was 5.2 ± 2.8 μm/minute (n = 11). Furrows that developed in margins 65 – 75 μm from the mitotic apparatus progressed at a rate of 10.8 ± 1.8 μm/minute (n = 12). The difference between the means is significant (P < 0.001; t = 6.04; 21 degrees of freedom). The ten fastest furrows progressed at a mean rate of 12.1 ± 0.2 μm/minute and the mean initial distance was 76.3 ± 6.7 μm. The ten slowest furrows progressed at a mean rate of 2.9 ± 0.9 μm/minute and the mean initial distance was 100.5 ± 8.7 μm. The difference between the means of the initial distance measurements is significant (P < 0.001; t = 6.97; 18 degrees of freedom). There was a positive correlation between the difference in initial distances and the difference in rates of progress of two furrows formed in the same cell (r = 0.68; P < 0.005; n = 37) as well as an inverse proportionality between the ratio of the rates of the slower and faster furrows and the ratio of the distances from the mitotic apparatus to the closer and more distant margins (r = 0.63; P < 0.005; n = 37).
Direct determination of the growth rate of Drosophila imaginal discs
Authors: Martin Presley F.
Published: June 2005

A simple technique is described which allows the number of cells in the imaginal discs of Drosophila melanogaster to be determined directly, by dissociation of the tissue into single cells. This technique was used to determine the growth rates for the eye‐antenna, wing, leg, and haltere discs during the second and third larval instars. The results obtained for the number of cells present at particular stages and for the growth rates during this period are similar to those determined previously using either indirect or more tedious procedures.
Volume regulation in an intertidal oligochaete, Clitellio arenarius (Müller). I. Short‐term effects and the influence of the supra‐ and subesophageal ganglia
Authors: Ferraris Joan D. , Schmidt‐Nielsen Bodil
Published: June 2005

Terrestrial oligochaetes demonstrate significant volume and osmoregulatory abilities that are under neurosecretory control. In the marine Oligochaete, little is known of volume or osmoregulatory capacities. However, histological evidence has linked cerebral neurosecretion and osmoregulation. The present study investigates water, ion, and volume regulation in an intertidal oligochaete and the effects of ablation of primary neurosecretory centers (supra‐and subesophageal ganglia) on these parameters. Control, sham‐operated, and ablated Clitellio arenarius were acutely transferred to diluted seawaters. Osmolality and Na, K, Cl (mEq/liter) concentrations were determined in total tissue water and in extracellular fluids. Extracellular volume was determined (using micropuncture techniques) as the fraction of the total tissue water in which 14C‐polyethylene glycol was distributed. With transfer to diluted seawater, all worms demonstrated hyperosmotic conformity. Tissue osmolality decreased in all animals at the same rate indicating no effect of ablation on integumental water permeability. Two phases of volume regulation were observed. In phase 1 (0–6 hours) osmolality decreased while water content (gm H2O/gm solute free dry weight = s.f.d.w.) increased both intra‐ and extracellularly. During this period, some volume regulation was accomplished in the control groups, particularly during the first 5 minutes, by the excretion of extracellular Na and Cl (μmoles/gm s.f.d.w.) which limited water gain. Ablated worms, reflecting less extracellular solute loss, gained more water than control groups. In phase 2 (6–18 hours) osmolality was constant, and all groups demonstrated a slow intra‐ (IC) and extracellular (EC) regulatory volume decrease. The solutes that accompanied volume loss were Na (EC), Cl (IC), and unmeasured solutes (IC). Reduction in intracellular solute content was the most significant loss occurring during this period with little difference among the groups tested. We hypothesize the primary effect of ablation is on extra‐ rather than intracellular volume regulation.
Physiology of cave arthropods in Hawaii
Authors: Ahearn Gregory A. , Howarth Francis G.
Published: June 2005

Lava tube caves in the Hawaiian Islands contain an impressive array of troglobitic arthropod species. These animals exhibit striking morphological adaptations to their subterranean environment including loss of eyes and body pigment, reduction or elimination of wings, and hypertrophication of chemosensory and tactile organs. Certain modifications of water balance and metabolic rates are also apparent in these cave‐adapted animals.

Neither Hawaiian troglobites nor their surface relatives can absorb water vapor from a saturated atmosphere even following a period of prolonged desiccation, whereas both forms are able to restore water deficits adequately through drinking. Lava tube crickets (34.5 and 52.3 μg cm−2 hour−1 mmHg−1) and spiders (33.4 μg cm−2 hour−1 mmHg−1) possess greater integumentary permeabilities than their epigean relatives (crickets, 26.2; spiders, 3.1 μg cm−2 hour−1 mmHg−1).

Hawaiian troglobitic crickets lack a diel metabolic rate (night = 279.5 ± 20.1; day = 280.8 ± 13.5 μl 02 gm−1 hour−1). The daily average metabolic rates of cave‐adapted (280.2 ± 15.3) and surface crickets (277.4 ± 9.8 μl 02 gm−1 hour−1) are not significantly different (P > 0.05), however, suggesting differential strategies of caloric utilization in the two environments which may be related to water availability.
Simultaneous measurement of evaporative water loss, oxygen consumption, and thoracic temperature during flight in a carpenter bee
Authors: Nicolson Susan W. , Louw Gideon N.
Published: June 2005

The carpenter bee Xylocopa capitata has a high wing loading (425 mg cm−2 in females with empty crops) and exhibits a very high mass‐specific oxygen consumption during flight (mean for free flight 52.3 ml O2 gm−1 hour−1). Evaporative water loss is also high during flight (26.6 mg gm−1hour−1) and is significantly correlated with rate of oxygen consumption (r = 0.73) as well as with temperature of the ambient air (r = 0.80) and the water vapor deficit (r = 0.66). No indication of active evaporative cooling was evident and the bees are true endotherms capable of rapid preflight thermogenesis. Analysis of the osmotic and ionic concentrations of the body fluids showed that no water stress was experienced by the bees.

The use of suitable thermocouples and a sensitive capacitance‐type humidity meter in an open flow‐through system allowed instantaneous and simultaneous measurement of oxygen consumption, evaporative water loss, and thoracic temperature. All three variables fluctuated in close synchrony during preflight warmup, flight, and subsequent cooling.
Monoaminergic mechanisms associated with control of luminescence and contractile activities in the coelenterate, Renilla köllikeri
Authors: Anctil Michel , Boulay Danielle , Larivière Luc
Published: June 2005

The effects of monoamines and adrenergic drugs on luminescent responses and rachidial contractions were investigated in the colony of the sea pansy Renilla köllikeri. Of several transmitter candidates tested, only adrenaline induced localized, phasic luminescence at low concentrations. Propranolol (1 mM) depressed adrenaline‐induced and suppressed electrically stimulated luminescence, the latter being also abolished by 6‐hydroxydopamine (6‐OHDA) and reserpine. Desmethylimipramine (DMI, 20 μM), an uptake inhibitor of adrenergic neurons, potentiated luminescent responses to both adrenaline and electrical stimulation, and induced luminescence at higher concentrations. Pargyline, a monoamine oxidase inhibitor, produced DMI‐like effects. Rachidial contractions in Renilla are biphasic events which are usually spontaneous and rhythmic, or can be induced by electrical stimulation. Noradrenaline and adrenaline enhanced the second phase of ongoing rhythmic contractions, but failed to induce contractions. Reserpine and 6‐OHDA abolished electrically stimulated luminescence, but reserpine further depressed evoked contractions while 6‐OHDA failed to affect rhythmic or evoked contractions. DMI (0.5 mM) initiated rhythmic contractile activity in quiescent preparations. These observations suggest that adrenaline or an as yet unidentified catecholamine may be involved as a neurotransmitter in luminescence control. Noradrenaline and/or adrenaline act possibly as neuromodulators for rachidial contractions in the sea pansy.