bluuebunny/crossref_metadata_2025 huggingface dataset:
Ontogenetic changes in water‐vapor conductance of eggs of yellow‐headed blackbirds (Xanthocephalus xanthocephalus)
Authors: Hanka Ladislav R. , Packard Gary C. , Sotherland Paul R. , Taigen Theodore L. , Boardman Thomas J. , Packard Mary J.
Published: June 2005

Eggs of Yellow‐headed Blackbirds were incubated in a forceddraft incubator, and conductance of eggs to water vapor was determined for eggs having undergone different amounts of development. Multiple regression analysis indicated that water‐vapor conductance is related to incubation time (expressed in both linear and quadratic forms) and to the length of pores through eggshells. Studies of geographic variation in conductance within a single avian species may be subject to serious sampling error if the eggs are at different stages of incubation at the time they are collected for study. Also, pore length is a better approximation to length of the diffusion pathway through an eggshell than is shell thickness.
Post‐exercise acid‐base disturbance in Gecarcinus lateralis, a Terrestrial Crab
Authors: Smatresk N. J. , Preslar A. J. , Cameron J. N.
Published: June 2005

Following enforced activity the hemolymph of Gecarcinus lateralis exhibits a “mixed” respiratory and metabolic acidosis. There is an elevation of hemolymph lactate and P levels and a reduction of total CO2. The lactate release is slow and peak concentrations are reached in 20 minutes. One hour after exercise hemolymph pH, total CO2 and P have returned to resting levels but lactate is elevated for four hours following activity. The metabolic acidosis is due only partly to lactate. A rapid change in base deficit following exercise appears to be independent of lactate concentrations.
Regulation of corticotype through kinety insertion in Tetrahymena
Authors: Nelsen E. Marlo , Frankel Joseph
Published: June 2005

Insertion of a new ciliary row (kinety) has been documented in cells of Tetrahymena thermophila subjected to certain nutritional shift‐down conditions. Under these conditions cells replace their oral structures and become rapid‐swimming, dispersal forms. During the oral replacement process cells with 18 or 19 kineties frequently add a kinety to express a corticotype (kinety number) of 19 or 20. Cells of corticotypes 20 or 21 do not change corticotype under these conditions. When cells undergo oral replacement upon entering stationary phase in nutrient medium, no increase in corticotype takes place even when the initial corticotype is 18 or 19. The increase in corticotype thus depends on the occurrence of oral replacement, the initial corticotype, and the nutritional shift‐down.

Examination of cells stained with protein‐silver indicates that a new kinety is inserted near the conclusion of the oral replacement process in a postoral position, between the two pre‐existing postoral kineties (1 and n). The process appears to involve the insertion of basal body couplets derived from the newlyformed undulating membrane. This process forms a third postoral kinety. One of the original postoral kineties (n) is eventually extended to the anterior end of the cell to the left of the new oral apparatus.

The present findings suggest that cortical stability characteristics are likely to be different under natural conditions, which are likely to involve periodic starvation, than they are under continuous cultivation in axenic nutrient media in the laboratory. It is predicted that under natural conditions a unique stability center near corticotype 20 will be manifested.
The effects of environmental oxygen levels on the respiratory function of hemocyanin in the crabs, Libinia emarginata and Ocypode quadrata
Authors: Burnett Louis E.
Published: June 2005

The respiratory function of the hemocyanin (Hcy)‐containing blood in the aquatic spider crab, Libinia emarginata, and the terrestrial ghost crab, Ocypode guadrata, was studied in animals exposed to normoxic and hypoxic conditions a t 25°C. In L. emarginata low concentrations of Hcy, although 90% O2, saturated at the gill, necessitate a high blood and water convection strategy. O. quadrata has blood with a higher concentration of hemocyanin which is 96% O2 saturated at the gill, obviating a very high rate of blood circulation. During progressive hypoxia convection initially increases on both sides of the gill in L. emarginata while in O. quadrata cardiac output decreases. Blood pH increases with decreasing ambient P, below 60 torr in L. emarginata, inducing a greater hemocyanin O2 affinity.
The effect of temperature on the male reproductive system of the common water snake (Nerodia sipedon)
Authors: Weil Michael R. , Aldridge Robert D.
Published: June 2005

The effect of various temperatures upon the male reproductive cycle of the common water snake (Nerodia sipedon) was studied. Snakes were divided into five groups and kept at five different temperature regimes and a 0L:24D photoperiod for ten weeks. Those kept in Chamber 1 were at 20°C the entire day while those kept in Chambers 2–5 were maintained at 21.3, 23.3, 27.4 and 29.3°C for eight hours per day respectively and 20°C for the remaining 16 hours each day.

Interstitial cell nuclear diameters, renal sexual segment tubule diameters and epithelial heights were found to be unrelated to increasing temperatures. Testicular growth was positively correlated to increasing temperatures. Seminiferous tubule diameters increased rapidly between 20 and 21.3°C with a Q10 = 39. Tubule diameters continued to increase, although at a slower rate, with further increases in temperature, with a Q10 = 1.72 between 21.3 and 29.3°C. Spermatogenesis increased with increasing temperatures; the threshold temperature for initiation of spermatogenesis was between 20 and 21°C.

Therefore, spermatogenesis and testicular recrudescence in Nerodia sipedon are temperature and not light dependent. Further, this report shows that weight of fat bodies does not affect normal spermatogenesis and testis growth in the presence of a sufficient food supply.
Polyspermy‐preventing mechanisms in mouse eggs fertilized in vitro
Authors: Sato Kodo
Published: June 2005

The time sequence of the mechanisms that prevent polyspermy in cumulus‐free mouse eggs was determined by continuous microscopic observations during in vitro fertilization. The zona reaction had begun, and the vitelline surface block to polyspermy was established, in less than one minute following sperm fusion with the vitellus. In less than five minutes, the zona reaction had advanced to the stage that no more spermatozoa could become firmly attached to the surface of the zona pellucida.
Composition of a protein antifreeze from larvae of the beetle, Tenebrio molitor
Authors: Patterson Jean L. , Duman John G.
Published: June 2005

A thermal hysteresis producing antifreeze protein was isolated from larvae of the beetle, Tenebrio molitor. This is the first thermal hysteresis protein purified from an insect. The specific activity of the Tenebrio antifreeze is somewhat greater than that of the fishes. The composition of the Tenebrio protein is quite different from those of the fish protein antifreezes. The most obvious difference is the lack of a large alanine component in the Tenebrio antifreeze. The significance of the differences are discussed.
Beat frequency is bimodally distributed in spermatozoa from T/t12 mice
Authors: Katz David F. , Erickson Robert P. , Nathanson Michael
Published: June 2005

Flagellar beat frequencies of spermatozoa from mice of varying genotype were studied using highspeed cinemicrography. Beat frequency was variable but unimodal in two inbred lines, their F1, and an outbred line. In contrast, beat frequency in spermatozoa from T‐complex, balanced lethal stocks (T/t6 and T/t12) tended not to vary between individual males of each genotype up to four hours after collection. The two‐hour distribution of beat frequency for T/t12 was, moreover, bimodal, suggesting the possible existence of two subpopulations of spermatozoa.
Toxicity to fish, effect on gill ATPase and gill ultrastructural changes induced by Pardachirus secretion and its derived toxin pardaxin
Authors: Primor Naftali , Sabnay Ilana , Lavie Vered , Zlotkin Eliahu
Published: June 2005

The ichthyotoxic mechanism of the Red Sea flatfish Pardachirus marmoratus crude secretion (PMC) and its derived toxin pardaxin was investigated using in vivo lethality tests and in vitro gill preparations of fish preadapted to different salinities. Comparative studies with ouabain and cytotoxin (a factor derived from cobra snake venom) were performed and it has been found that: 1) The lethal potencies of PMC increased in fish adapted to salinities above and below the isotonic level. 2) In contrast to PMC and pardaxin the lethal effects of ouabain and cytotoxin were weak upon external application and potent by injection. 3) When compared to ouabain, pardaxin was found to be about three and five orders of magnitude more potent gill ATPase inhibitor in fish and crustacean preparations, respectively. 4) EM studies of gills obtained from fish treated by sublethal doses of PMC revealed the appearance of apical crypts in gill chloride cells.
Seasonal variation of antifreeze peptide in the winter flounder, Pseudopleuronectes americanus
Authors: Petzel David H. , Reisman Howard M. , Devries Arthur L.
Published: June 2005

Serum ion concentrations, freezing and melting points were determined for the winter flounder, Pseudopleuronectes americanus collected from Shinnecock Bay, Long Island over the course of one year. Melting points and ion concentrations showed little variation, however freezing points decreased to a low of −1.7°C during the winter. Serum freezing points‐melting points were used as estimates of the amount of antifreeze peptide present in each monthly sample. Antifreeze peptide levels were highest (25 mg/ml serum) during the winter and less than 1 mg/ml during the summer.

A comparison of the concentrations of antifreeze peptide present in flounder from Shinnecock Bay with concentrations reported in flounder from Conception Bay, Newfoundland showed that both populations synthesize their antifreezes at the same time despite differences in temperature and photoperiod. However flounder from Conception Bay retain higher concentrations during the spring, presumably because of the lower water temperatures there.
The quantitative role of haemocyanin in the respiration of abalone (genus Haliotis)
Authors: Ainslie Robert C.
Published: June 2005

The bloods of the gastropod molluscs Haliotis ruber, H. laevigata, and H. roei deliver respectively 0.56 vol %, 0.62 vol %, and 0.90 vol % of oxygen to the tissues per circulatory cycle at the acclimation temperature 20°C. In each case over 80% of the oxygen delivered is bound to the haemocyanin. The greater amount of oxygen delivered by the blood of H. roei results primarily from the consistently higher haemocyanin concentration, hence oxygen carrying capacity, of the blood of, this species. It is hypothesized that this may be advantageous to this mobile, active abalone species by reducing the load on the circulatory system in maintaining respiration during activity.

Following an abrupt temperature increase from 20°C–25°C the oxygen delivered by the blood to the tissues per circulatory cycle decreases in all species, the most marked decrease being in H. roei which only delivers 67% of the 20°C value. In each case however, over 80% of the total delivered oxygen is still carried by the haemocyanin. Owing to the large oxygen carrying capacity of H. roei haemocyanin, the absolute amount of oxygen delivered per cycle is still larger than that in theother two species. A large reverse Bohr effect is apparent in all species at both temperatures, but its importance to the abalone is not clear when their mode of existence is considered.
Trochlear nerve regeneration in Xenopus laevis larvae
Authors: Fangboner Raymond F. , Luncsford Amelita P. , Vanable Joseph W.
Published: June 2005

The trochlear nerve of Xenopus laevis larvae was sectioned in the orbit, and the nerve distal to the section was removed, so that it could not serve to guide the return of the regenerating nerve to the superior oblique muscle (SOM). In a second series, in addition to removing the distal nerve segment, the SOM was removed or damaged. The regeneration pattern of the trochlear nerve fibers was recorded in situ at 1 to 5‐day intervals with the aid of methylene blue staining. The early growth ofregenerating fibers was multidirectional; only some fibers encountered the SOM by day 6 or 7; others reached nerves, inappropriate muscle, and other tissues. Ultimately, the fibers that reached the SOM persisted and were reinforced, while those that reached other locations were withdrawn. By 20 days or so, the regenerated trochlear nerve usually had an appearance that was close to that of an uncut nerve. In the second series, in which the SOM was removed or damaged, the multidirectional character of the growth persisted through 20 days after section. These data suggest that: 1) Trochlear nerve regeneration is not guided by cues that closely control fiber growth along a direct path to the SOM, and 2) The SOM acts as a trap for regenerating trochlear nerve fibers, promoting the maintenance and the fasciculation of the trochlear nerve fibers that reach it, and the degeneration of the fibers that do not.
A fast‐oxidative crustacean muscle: Histochemical comparison with other crustacean muscle
Authors: Silverman Harold , Charlton Milton P.
Published: June 2005

The present study describes a fast contracting, fatigue resistant, highly oxidative muscle found in the mouth parts of decapod crustaceans. The muscle studied was isolated from the blue crab, Callinectes sapidus. Histochemical techniques modified from those commonly used in mammalian striated muscle fiber typing were used to facilitate comparison of this fast‐oxidative muscle with other crustacean muscle. Comparison was made between this muscle and the slower cheliped opener muscle and the levator muscle of the fifth periopod. Differences in both SDH activity and myofibrillar ATPase activity between these muscles are described. The advantages and the difficulties involved in interpreting the histochemical reactions of various crustacean muscle fibers are also reviewed.
The symbiotic association between intracellular zoochlorellae (chlorophyceae) and the coelenterate Anthopleura xanthogrammica
Authors: O'Brien Timothy L.
Published: June 2005

The ability of intracellular marine zoochlorellae (Chlorophyceae) to provide their host with photosynthetically fixed carbon in vivo or with algal by‐products via hetrophagy or autophagy is examined in the coelenterate A nthopleura xanthogrammica. Algae do fix 14CO2 within the gastrodermal tissue layer of the host and the level of 14C present within the gastrodermis is dependent upon the nutritional state of the host. The various techniques used to detect the percent light‐fixed 14C present within the tissues of the host result in values ranging from less than zero to 3.9%, independent of the nutritional state of the host, indicating that relatively small amounts of soluble fixed carbon are translocatedto, the host's tissues. Acid phosphatase reaction product is absent within vacuoles containing algae; cellular debris which co‐occurs within these same vacuoles is also free of reaction product, suggesting that the presence of an alga within a vacuole inhibits (in an unknown manner) the cellular digestive processes of the host. Further, reaction product is restricted to the exterior of the cell wall following expulsion of algae into the host's coelenteron, suggesting that the cell wall is resistant tolysosomal hydrolase activity. The distribution of acid phosphatase reaction product in situ suggests that little in the way of algal by‐products would be made available to the host by the process of heterophagy or autophagy.
Action spectrum for ultraviolet irradiation inactivation of a cytoplasmic component(s) required for neural induction in the amphibian egg
Authors: Youn B. Woo , Malacinski George M.
Published: June 2005

An action spectrum was established for the destruction by ultraviolet radiation of cytoplasmic components of the neural induction system in the eggs of the South African clawed frog, Xenopus laevis. The action spectrum showed a peak at 280 nm and a decline towards both 250 nm and 320 nm after quantum corrections were made. These results are compatible with the assumption that proteins are involved in the initial photoreaction.
Induction of triploidy in Xenopus laevis by heat shocking of the egg before and after fertilization
Authors: Cassidy Donna M. , Blackler Antonie W.
Published: June 2005

Eggs of the frog Xenopus laevis have been subjected to a temperature shock before or after fertilization. The shock provokes triploidy through suppression of elimination of the second polar body; application of the shock within ten minutes of fertilization was associated with triploid frequencies to 90%. All series in which eggs were shocked after fertilization manifested some abnormal development in the surviving eggs, the greatest abnormality frequency correlated with the period of greatest sensitivity for the induction of triploidy. Up to 50% triploidy was induced in the eggs of certain females when the temperature shock was applied before fertilization. In these series, the capacity for normal development was not appreciably lowered by the treatment. A comparison is made between thermal and pressure techniques for the induction of triploidy.
In vivo conduction properties of regenerating giant nerve fibers in earthworms
Authors: Balter R. J. , Drewes C. D. , McFall J. L.
Published: June 2005

Non‐invasive electrophysiological techniques have been used to study spatial and temporal aspects of conduction properties in regenerating earthworm giant nerve fibers. The initial coupling of medial giant fiber (MGF) spikes across the lesion can occur as early as five (and usually within seven) days after severing the ventral nerve cord. In the case of the lateral giant fiber (LGF), the initial coupling of spikes across the lesion occurs as early as 12 days after severing the cord. During the first, few days after initial coupling across the lesion, properties of the recovering giant fibers included: a) intermittent and labile coupling of spikes across the lesion, b) long conduction times (up to 6 msec) across the lesion, c) frequent occurrence of, “rebound” spikes initiated in the lesion area, and d) similarity of conduction properties across the lesion for orthodromic and antidromic spikes. Three to four weeks after initial coupling, the following changes were observed: a) increased tendency for,1:1 coupling of spikes across the lesion, b) reduction in conduction time across the lesion, and c) decreased tendency for “rebound” spikes. The results are consistent with a model in which conduction across the lesion, during the first few days after initial coupling and thereafter, occurs by means of an electrical junction established between the severed giant fibers.
Further evidence for visual cell independent light effect on retina development in Tilapia leucosticta (teleostei)
Authors: Grün Gerd
Published: June 2005

The earlier conclusion that the influence of light on retina development in Tilapia leucosticta is not mediated by the visual cells has been tested by application of various light regimes. The effect of 10 days of continuous light resp. darkness on the growth of the inner plexiform layer is mimicked by only 24 hours of light resp. darkness when given on day 4. This is long before rods and cones become differentiated.
Effect of cAMP and related compounds on newt epidermal cell migration both in vivo and in vitro
Authors: Dunlap Mary K. , Donaldson Donald J.
Published: June 2005

The effect of cyclic AMP and related compounds on both in vivo and in vitro epidermal cell migration during wound closure in the adult newt was examined. Cyclic AMP (cAMP) mand N6, O2′‐didbutyryl cyclic AMP (bd‐cAMP) inhibited migration both in vivo and in vitro when used with equimolar concentrations of theophylline, an inhibitor of 3′, 5′‐cyclic nucleotide phosphodiesterase. Neither db‐cAMP nor theophylline alone inhibited migration in vivo. Adenosine 5′ monophosphate (AMP), cyclic guanosine 3′, 5′ monophosphate (cGMP) and imidazole, a potentiator of phosphodiesterase were tested in vivo and had no effect on migration. Isoproterenol and epinephrine, which are known to stimulate adenylate cyclase, inhibited migration in vitro. Experiments using the protein synthesis inhibitor, cycloheximide, suggest that cAMP could be acting partially through regulation of protein synthesis but that other factors are involved. Dibutyryl cyclic AMP and theophylline had no effect on the incorporation of 3H‐leucine into protein. The inhibition of migration both in vivo and in vitro provides further evidence for a role of a cAMP in the regulation of cell motility.
Amino acid metabolism and cell volume regulation in the little skate, Raja erinacea. II. Synthesis
Authors: King Patricia A. , Cha Chung‐Ja , Goldstein Leon
Published: June 2005

The capacity for synthesis of β‐alanine, sarcosine, and taurine was investigated in tissue slices from the little skate (Raja erinacea). Synthesis of β‐alanine was found to occur predominantly in the liver and at a rate comparable to the β‐alanine oxidation rate previously measured for this tissue. Synthesis rate did not change when tissues were incubated in a diluted saline medium or when skates were gradually acclimated to half‐strength seawater. Sarcosine was found to be synthesized primarily in the liver, but at a much lower rate than β‐alanine. Taurine synthesis could not be demonstrated definitely in any of the tissues tested. Amino acid analysis of liver, red blood cells, and wing muscle were performed on tissues of skates gradually acclimated to half‐strength seawater and then reacclimated to full‐strength seawater. Only β‐alanine levels returned to predilution values upon reacclimation to full‐strength seawater.
In vitro translatability of RNP‐particles from insect eggs and embryos (Smittia spec., Chironomidae, Diptera)
Authors: Jäckle Herbert
Published: June 2005

Maternal messenger ribonucleoprotein (mRNP)‐particles from eggs and mRNP‐particles from embryos of the chironomid midge Smittia spec. were compared with respect to translatability in a mRNA‐dependent cell‐free translation system. The reticulocyte lysate system used was almost not stimulated by addition of native cytoplasmic mRNP‐particles from both eggs and embryos. RNP‐particles from embryos were fully translatable after partial release of proteins by high‐salt treatment. However, complete removal of proteins was necessary for translation of mRNP‐particles from eggs. Maternal mRNP‐particles of eggs consist of salt‐resistant RNP‐core proteins, which repressed translatability of the associated mRNA. The data support the hypothesis of “masked” maternal mRNA in insect embryos.
Effects of RNA inhibitors on the development of Drosophila embryos permeabilized by a new technique
Authors: Arking Robert , Parente Anthony
Published: June 2005

The molecular analysis of Drosophila embryogenesis has been hindered by the impermeable nature of the vitelline membrane, which has made it difficult to introduce exogenous substances into the developing embryo. We have developed a modification of the permeabilization technique of Limbourg and Zalokar ('73) in which octane is used to permeabilize the vitelline membrane and dimethylsulfoxide is used to facilitate the transport of exogenous substance across the cell membranes. The procedure is highly effective (ca. 95%) and is consistent with a high frequency of normal development. We have used this technique to analyze the effect in vivo of four inhibitors of RNA synthesis (alphaamanitin, actinomycin‐D, rifampin, and rifamycin SV) on the embryogenesis of Drosophila. We have found that there are characteristic stage‐specific alternations in the sensitivity of the embryo to these inhibitors which is reflected both by changes in the ID50 dosages and by changes in the developmental abnormalities caused by the drugs. Embryos aged 2–12 hours old undergo a developmental arrest within 30 minutes after application of the inhibitors. Embryos older than 12 hours are able to develop for 140+ minutes after treatment before arresting. The effects of these drugs are consistent with the idea that there exists a definite sequential program of gene activity that is necessary to the normal embryonic development of Drosophila.
Innervation of the crayfish thoracic deep flexor musculature
Authors: Crabtree Robert L. , Sherman R. G.
Published: June 2005

The innervation and neuromuscular physiology of the deep flexor muscles in the thorax of the crayfish, Orconectes rusticus are described. Four muscles arise ventrally from the endophragmal shelf and join at segmental inscriptions to form a single functional mass. Deep flexor 1 (DF1) extends from the anterior thoracic endoskeleton to be joined by DF2, DF3, and DF4 in more posterior segments. The mass inserts on the abdominal flexor at the common flexor inscription.

Motor axons from thoracic ganglionic third roots 1–3 innervate the deep flexor muscles. Light and electron microscopical examination indicates that the third root of the first thoracic ganglion contains only three or four axons that innervate the musculature, and the third root of the second thoracic ganglion usually contains five. The largest number of deep flexor axons (10) occurs in the third root of the third thoracic ganglion.

Methylene blue staining and microelectrode recording methods show that each deep flexor muscle fiber is innervated by three motoneurons: the motor giant, a non‐giant excitor and an inhibitor. The motor giant elicits excitatory postsynaptic potentials (EPSPs) that rapidly antifacilitate, while the non‐giant excitor elicits EPSPs that do not antifacilitate. Both excitors produce spiking activity in the deep flexors. The inhibitory motor neuron reduces the amplitude and duration of the EPSP and prevents spiking activity. These results show that the thoracic deep flexor system is similar to the homologous system in the abdomen.
Entire litters developed from transferred eggs in whole body X‐irradiated female mice
Authors: Lin T. P.
Published: June 2005

The sensitivity of mouse eggs to sublethal X‐irradiation was determined in vitro and in vivo with regard to the development of donor litters in foster mothers. One thousand seven hundred fifty‐eight unfertilized eggs of agouti dark‐eyed donor mice were transferred into 293 unirradiated or X‐irradiated, mated female pink‐eyed mice. Two hundred thirty‐nine recipients became pregnant; of these 35 produced litters containing solely dark‐eyed fetuses. Sublethal doses of X‐radiation administered to donor eggs in vitro before transferring into unirradiated recipients did not influence significantly the number of litters of exclusively dark‐eyed fetuses produced. However, recipients irradiated by 250 roentgens (r) produced more solely dark‐eyed litters than did those irradiated with 100 r. In 21 pregnant females irradiated by 100 r, only 3 (14%) developed solely dark‐eyed fetuses as compared to 22 pregnant females irradiated by 250 r, of which 13 (59%) developed solely dark‐eyed fetuses, all from unirradiated, transferred eggs. Of another group of 22 pregnant females which received 250 r body irradiation and subsequently received eggs also irradiated by 250 r, only 7 (32%) produced litters of dark‐eyed fetuses. No one female of these three groups carried native fetuses. Such radiation‐induced infertility resulting from damage of native eggs rather than loss of the mother's ability to carry a pregnancy, is frequently remedied by egg transfer.
Morphogenetic movements in acipenserid embryos
Authors: Ballard William W. , Ginsburg Anna S.
Published: June 2005

A fate map for the late blastula stage of a sturgeon is presented for the first time, together with descriptions of the principal morphogenetic movements, and a timetable of involution, based on vital dye experiments on Huso and three species of Acipenser. Massive migration of internal cells from the blastocoel roof to an inner marginal zone precedes the earliest drift of cells at the surface. The definitive endoderm which lines the archenteron is derived from a complete band of cells encircling 360° of the surface of the blastula from the equator up to 20° latitude. Their movement across the lips of the blastopore to the interior is strictly defined as an involution, not an invagination. After involution of the prechordal endoderm, the right and left components of the sub‐notochordal endoderm fuse with each other as they pass across the blastopore lip in the midline. Above the band of prospective endoderm on the blastula surface there is a complete band of both surface and inner marginal cells up from 20° to about 30° latitude, which produces notochord and somite mesoderm, also by involution. Mesoderm of the tail has all reached the interior before closure of the blastopore. Head mesoderm, and intermediate and lateral plate mesoderm are not represented at or near the blastula surface. The neural plate is derived from material at and immediately inside the blastula surface lying above 30° latitude and between right and left 90° longitudes.

The remarkable contrast between the morphogenetic movements and fate maps of the meroblastic teleost and the holoblastic sturgeon embryos—both actinopterygian fishes—and the close resemblance of sturgeon embryos to those of frogs, are discussed.
Developmental and ploidy characteristics of “senescent” unfertilized eggs of Xenopus laevis
Authors: Blackler Antonie W. , Cassidy Donna M.
Published: June 2005

Unfertilized eggs of Xenopus laevis have been stored in a high salt physiological saline (De Boer's solution) over a period of about 24 hours. During this time, aliquots have been subjected to lowered salinity and fertilized. The stored eggs undergo a defined series of morphological changes, which are initially reversible upon fertilization. Length of storage may have little or no effect on the capacity of the eggs to undergo cleavage, but the normal developmental capacity declines with increasing storage time. Among the characteristics of this decline is a regressive cytokinesis, early arrest, and the appearance in surviving larvae of a definable syndrome of morphological type. Increasing storage times predispose the eggs to subsequent triploid development, the triploidy arising as a consequence of failure of second polar body emission. The possible interest of these findings for a model system of mammalian gamete aging is discussed.
Appearance of RNA with a specific size class of poly(A) in oocytes and eggs in HCG‐stimulated Xenopus laevis females
Authors: Sagata N. , Shiokawa K. , Yamana K.
Published: June 2005

Using a 3H‐poly(U) binding technique, poly(A) content has been measured in Xenopus laevis eggs consisting of two groups: one was obtained from females 12 to 16 hr after a single injection of human chorionic gonadotropin (HCG) (designated “unstimulated” eggs), and the other was obtained one week later from the same females by the second injection of the hormone (“stimulated” eggs). The stimulated egg contained about a 1.2‐fold larger amount of poly(A) than the unstimulated one. Gel electrophoresis has revealed that this slight but reproducible increase in the poly(A) (i.e., about 80 nucleotides long). This poly(A) was also detectable in the oocytes obtained one week after a single injection but not in those from uninjected females. Poly(A)+ RNA was analyzed by sucrose density gradient centrifugation, and it has been shown that most of the 80 nucleotidelong poly(A) sequences in the stimulated eggs were associated with RNA whose size distribution was less heterogeneous than, and hence distinguishable from, that of the bulk poly(A)+ RNA. The possibility is discussed that HCG hormone may stimulate the synthesis of a specific class of poly(A)+ RNA in smaller oocytes, which may not normally take place to a significant extent during maturation.
Isolation of pituitary proteins from Mexican axolotls (Ambystoma mexicanum COPE) by polyacrylamide gel electrophoresis. I. Assay for thyrotropic activity
Authors: Schultheiss Hartmut
Published: June 2005

Pituitaries from male, sexually mature neotenic axolotls were subjected to polyacrylamide gel electrophoresis (PAGE). Eight protein fractions were isolated from unstained gels. They were tested for thyrotropic activity in two different systems: 1) 131iodide uptake into the thyroids of hypophysectomized neotenic axolotls was followed over a 72‐hour period after pretreatment with the protein fractions (one pituitary‐equivalent per animal and day); 2) The thyroxine (T4)‐release in vitro from thyroid glands was measured by radioimmunoassay (RIA). PAGE fractions were added to the culture medium. Three fractions (A1, A2, and A4) were found to increase 131iodide uptake significantly. Specific release of T4 by axolotl thyroid glands was stimulated by only one fraction (B2), corresponding to the two fractions (A1 and A2) which caused the greatest 131I uptake. The T4‐release was dose‐dependent, and on a μg‐basis, axolotl‐TSH, (a‐TSH), B2, was approximately eight times more potent than the reference bovine TSH (b‐TSH), NIH‐TSH‐B8. It was shown the pituitary of neotenic axolotls contains proteins with high thyrotropic activity.
Age‐ and region‐dependent redistribution of con A binding sites on chick wing‐bud mesoderm cells
Authors: Paulsen Douglas F. , Finch Robert A. , Parker Curtis L.
Published: June 2005

The distribution of concanavalin A (con A) binding sites on chick wing‐bud mesoderm cells from two different developmental stages and from different regions of the same embyronic limbs was examined. Fluorescein isothiocyanate (FITC)‐labeled con A binding sites on mesoderm cells from whole stage 19–20 and the distal third of stage 25 limbs redistributed from a random array over the cell surface to form clusters or caps of binding sites. In contrast, a significantly smaller percentage of developmentally “older” mesoderm cells from the proximal third of stage 25 limbs underwent redistribution of bound con A from its normal random arrangement. In order to further examine the basis for the decrease in con A redistribution in the stage 25 proximal cells, this segment was subdivided into a core (presumptive chondrogenic) and peripheral (presumptive myogenic) region. The results of con A redistribution studies utilizing these two cell populations indicate that a significantly smaller percentage of the core cells are capable of forming clusters or caps. Likewise, in agglutination studies, core cells proved significantly less susceptible to con A‐induced agglutination. These findings indicates that the differences in agglutination and con A redistribution, seen when comparing the proximal cells with the other cell populations, is attributable to a subpopulation of the proximal cells, specifically, those located in the chondrogenic core region. Since the proximal core and peripheral cells are of the same developmental age, these findings suggest that developmental age is not solely responsible for the differences reported here. Thus, prospective phenotype appears also to be involved in the decreased agglutination and a con A redistribution of the chondrogenic core cells.
Lanthanum blockade of serotonin release from the branchial nerve of the mussel Mytilus edulis
Authors: Stefano G. B. , Brogan J. J. , Aiello E. , Hiripi L.
Published: June 2005

The study demonstrates that lanthanum at low levels (5mM) can block the neuronal release of serotonin. In addition, the postlateral ciliated cell serotonergic receptor is not affected by this blockade at this particular concentration of lanthanum, but is affected at higher levels (10 mM).
An experimental analysis of shoulder and lateral body wall development in the chick embryo
Authors: Yander Gail , Searls Robert L.
Published: June 2005

Development of the shoulder and a change in the axis of outgrowth of the wing in the chick embryo have been shown to be accompanied by morphogenetic movements in the lateral body wall adjacent to the base of the wing. The manner in which the cells moved was studied by grafting labeled mesoderm into unlabeled hosts and by periodic photographs of carbon particles placed in live embryos. Histological techniques were used to determine the final location of the markers, and maps were constructed of the cell movements. It was observed that cells in the lateral body wall cranial to the wing and overlying the pleural coelom moved caudally to form the base of the shoulder. This movement occurred between stage 23 and stage 27. Starting at stage 25, the cells in the lateral body wall caudal to the wing moved ventrally and then cranially to form the sternum and connective tissue of the ventro‐medial thoracic body wall; this movement was complete by stage 31. As a result of these two morphogenetic movements, cells in the proximal portion of the wing were also displaced. The net effect is formation of the shoulder, while the base of the wing rotates ventrally with respect to the somites.
Relation of mitochondria‐rich chloride cells to active chloride transport in the skin of a marine teleost
Authors: Marshall William S. , Nishioka Richard S.
Published: June 2005

Mitochondria‐rich cells in the skin of the marine teleost, Gillichthys mirabilis, were found to be ultrastructurally similar to typical chloride‐secreting cells of marine fish gill, but had a tall, spindlelike shape due to the thickness of the stratified epithelium. The fluorophore, dimethylaminostyrylethylpyridiniumiodide (DASPEI), was used to visualize and count skin chloride cells so that cell density could be regressed against the in vitro short‐circuit current (ISC) measured on the same tissue. The regression (r2 = 0.76; n = 72) demonstrated that chloride cells are responsible for anion transport across Grillichthys skin.
Ecdysteroid titers of juvenile lobsters following molt induction
Authors: Chang Ernest S. , Bruce Marilyn J.
Published: June 2005

By means of radioimmunoassay, the circulating ecdysteroid (molting hormone) titers have been obtained for both normal and eyestalkablated juvenile lobsters. It is seen that these animals, following molt induction, have rapid elevations in their hemolymph ecdysteroids. The hormonal titers for these premolt‐induced animals closely resemble those of normal animals. In addition, the effects of temperature upon molting and ecdysteroid titers are examined in ablated lobsters.
Interlimb coordination in 20‐day‐old rat fetuses
Authors: Bekoff Anne , Lau Bradley
Published: June 2005

Evidence for short sequences of interlimb coordination was found in 20‐day‐old rat fetuses. Frame‐by‐frame analysis of videotape records showed phase relationships indicating a pattern of alternation in sequences involving forelimb‐forelimb and hindlimb‐hindlimb coordination. Forelimb‐hind‐limb coordination was not observed.
Abdominal extension‐evoking interneurons in crayfish: Characteristics of the ganglionic driving networks
Authors: Williams Benjamin J. , Larimer James L.
Published: June 2005

Several different paradigms of extension‐evoking command fiber (CF) stimulation were used in order to characterize functional properties of the networks controlling abdominal posture in the crayfish. The types of connections between CFs and abdominal postural driving networks were first studied by stimulating several extension CFs from the same preparation at different frequencies. Differences in the recruitment order of extensor motoneurons imply that each CF makes unique synaptic connections with the abdominal ganglionic driving interneurons and/or the postural efferents. Furthermore, the ability of an extension CF to activate excitatory efferents after another extension CF has been driven to fatigue suggests that each CF has functionally distinct pathways to the extensor motoneuron pool. The second main objective of this paper was to determine if direct extension CF stimulation would produce integrative properties of the driving networks similar to those seen previously in the reflexively extending animal. As in reflex‐evoked behavior, the ganglionic driving networks are capable of spatially summating the input from two co‐activated CFs. In particular, low frequency co‐activation of two CFs recruited motoneurons which were inactive when single CFs were stimulated alone at the same frequency. Co‐stimulation of an extension CF with strong flexor‐biasing sensory input suppressed the flexors and resulted in a nearly pure extension motor program similar to that seen during reflex‐evoked extensions. Thus, overriding of antagonistic reflexes by CF activity argues for synaptic systems in each ganglion which rejects or reduces the gain of opposing relflexes, including those due to reafference during the commanded movements. These results strongly suggest a causal role for CFs in the generation of reflexive behavior in the freely behaving animal.
Norepinephrine: Its presence in the central nervous system of the bivalve mollusc, Mytilus edulis
Authors: Stefano George B. , Catapane Edward J.
Published: June 2005

The present study demonstrates the existence of norepinephrine in the ganglia of the mussel Mytilus edulis. The identification of this catecholamine is based on the specificity of the radioenzymatic and spectroflurometric methods of analysis and by the specific actions of FLA‐63. Key words: norepinephrine, radioenzymatic, FLA‐63‐DOPS, invertebrate nervous tissue.
Histochemical determination of the fiber composition of locomotory muscles in a lizard, Dipsosaurus dorsalis
Authors: Putnam Robert W. , Gleeson Todd T. , Bennett Albert F.
Published: June 2005

A histochemical survey was done on the fiber composition of 12 different locomotory muscles in the lizard Dipsosaurus dorsalis. Three types of fibers were found in all muscles: (1) fast‐twitch‐glycolytic (FG); (2) fast‐twitch‐oxidative‐glycolytic (FOG); and (3) tonic fibers. Virtually all locomotory muscles contain some tonic fibers. Most muscles have bulk white regions (containing mostly FG fibers) and distinct red, oxidative regions (with FOG and tonic fibers). These red regions are predominantly located around the joints in the hind limb muscles, and probably serve a postural and joint‐stabilizing function. The predominance of FG fibers in the bulk white regions is well‐correlated with the rapid, anaerobically supported predator escape behavior of D. dorsalis.
Proliferation, growth, and migration of nuclei the yolk syncytium of Salmo and Catostomus
Authors: Long Wilbur L.
Published: June 2005

Nuclei of the yolk syncytial layer (YSL) were counted, measured, and mapped at several stages of morphogenesis selected representatives of the Clupeiformes and Cypriformes. The data show coordated motion of nuclei before and durg morphogenetic movements of the cellular blastodisc. This motion may be used to trace cytoplasmic flow the syncytium at early stages. The data show that YSL nuclei proliferate mitotically at first. Further proliferation, after mitosis ceases, happens by an unknown mechanism. Growth of YSL nuclei Salmo gairdneri does not occur by fusion of smaller nuclei as others have suggested for teleosts. The matter is still unsetted for Catostomus commersoni.
In vitro capacitation and the chemically induced acrosome reaction in bovine spermatozoa
Authors: Byrd William
Published: June 2005

The effect of bovine serum albumin (BSA), calcium, and ionophore A23187 on in vitro capacitation and the induction of the acrosome reaction in bovine spermatozoa was examined using light, fluorescent, and electron microscopy and spectrofluorometry. Transmission electron microscopy of fixed spermatozoa labeled with the plant lectin concanavalin A indicated that a significant redistribution of lectin binding sites requires at least three hours of incubation in a capacitating medium that contains BSA and calcium. Spermatozoa underwent capacitation and the acrosome reaction following a minimum incubation time of 2–3 hours in capacitating medium in the continuous presence of calcium ionophore A23187 (1–10 μm). The induction of the acrosome reaction was determined by light microscopy of fixed‐stained cells as well as transmission electron microscopy. These data suggest that a minimum of 2–3 hours is required for in vitro capacitation of bovine spermatozoa. Capacitation was also examined using the tetracycline‐HCl (T‐HCl) binding assay of Ericsson ('67). Measurement of fluorescence by spectrofluorometry and by fluorescence microscopy demonstrated that the level of fluorescent T‐HCl bound to spermatozoa was dependent upon the concentration of BSA, the presence of calcium, and time of incubation. However, the loss of bound T‐HCl does not coincide with the development of the capacitated state determined by lectin binding and induction of the acrosome reaction. It is suggested that this loss of fluorescence may represent either a preliminary step in capacitation or result from nonspecific binding of fluorescent label to BSA.
Glycogen metabolism in the developing accessory lobes of Lachi in the nerve cord of the chick: Metabolic correlations with the avian glycogen body
Authors: Benzo Camillo A. , De Gennaro Louis D.
Published: June 2005

Glycogen synthase, glycogen phosphorylase, glucose‐6‐phosphate dehydrogenase, 6‐phosphogluconate dehydrogenase, and glucose‐6‐phosphatase were determined for the first time in the accessory lobes of Lachi from late embryonic chicks. The activities of these enzymes were compared with those found in other glycogen‐metabolizing tissues, specifically the glycogen body, liver, and skeletal muscle, obtained from the same embryos. The data show that, as in the glycogen body, the accessory lobes of Lachi lack glucose‐6‐phosphatase, but contain relatively high activity levels of glycogen synthase I, total and active glycogen phosphorylase, and the dehydrogenases of glucose‐6‐phosphate and 6‐phosphogluconate. The percent of glycogen synthase I activity in the Lachi lobes is from two‐ to 20‐fold greater than that observed in the glycogen body, liver, or muscle, whereas the percent of glycogen phosphorylase a activity is comparable to that of the liver, but greater than that in the glycogen body or muscle. The activity of each dehydrogenase of the pentose phosphate cycle in the Lachi lobes is similar to that noted in the glycogen body, but is over two‐ or fivefold greater than that activity found in muscle or liver. Our data, together with other recent evidence, suggest that the role of glycogen in these functionally enigmatic tissues may be to support the precocious process of myelin synthesis in the developing bird, as well as possibly to provide alternate sources of energy for the avian central nervous system.
Glycoprotein secretions of the epididymis in the rabbit and hamster: Localization on epididymal spermatozoa and the effect of specific antibodies on fertilization in vivo
Authors: Moore H. D. M.
Published: June 2005

To assess the functional significance of glycoprotein secretions of the rabbit and hamster epididymis during sperm maturation and fertilization, antibodies have been raised against acidic protein fractions isolated from epididymal fluid. Specific antiserum was elicited against each of three rabbit glycoproteins designated R1, R2, and R3 with isoelectric points of pI 3.45, 4.15, and 4.65 respectively, and against one hamster glycoprotein (HI), pI 3.40.

Epididymal glycoproteins on the surface of washed spermatozoa from various regions of the epididymis were localized by the fluorescent antibody technique and by sperm agglutination with antiserum. They were first detected on restricted regions of spermatozoa from the distal caput and corpus epididymidis and each antigen had a characteristic binding pattern. The effect of specific antibodies on fertilization in vivo was tested in rabbits by preincubating cauda epididymal spermatozoa with heat‐treated antiserum or univalent immunoglobulin fragments before their deposition into oviducts of does induced to ovulate. In all cases, fertilization rates were significantly reduced (P ≤ 0.05) compared with controls, the most effective antiserum being against glycoprotein antigen R1 found only on the anterior acrosome of spermatozoa. Heat‐treated antiserum against H1 glycoprotein placed in the bursal cavity of ovulating females significantly inhibited fertilization in the hamster (P ≤ 0.005). These results are discussed in relation to the modification to the sperm plasmalemma during maturation.