bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neural factors and evitability in insect behavior
Authors: Roeder Kenneth D. 
Published: June 2005

AbstractCompared with more complex behavior patterns involving goal selection, evasive behavior of prey animals elicited by the presence of a natural predator is usually considered to be relatively inevitable and stereotyped. Noctuid moths, while flying in the field at night, show two types of evasive response pattern when their tympanic organs detect the ultrasonic cries of marauding insectivorous bats. Since sound is the sole communication channel between prey and predator, this situation invites neurophysiological and behavioral analysis. When, in the course of studying this behavior, moths are removed by stages from the natural circumstances of this interaction their evasion responses become much less invariant; that is, more evitable. The possible survival value of some evitability in this behavior under natural circumstances is discussed. The afferent nerve response of the noctuid auditory organ is highly stable; therefore, the source or sources of this evitability must lie down‐stream in the moth central nervous system. Acoustic interneuronal systems within the thoracic ganglia and the brain have been examined for lapses in responsiveness and for other indications of transsynaptic instability that might correlate with the demonstrated behavioral evitability.
Photoreceptor processes: Some problems and perspectives
Authors: Goldsmith Timothy H. 
Published: June 2005

AbstractVisual photoreceptors from both vertebrates and invertebrates are characterized by extensive elaboration of membrane which contains visual pigment (rhodopsin). Visual pigments in all phyla examined are chemically similar: the chromophore is 11‐cis retinaldehyde attached by an aldimine linkage (Schiff base) to a membrane protein, opsin. The effect of light is to isomerize the chromophore to the all‐trans configuration. Beyond these fundamental similarities, several specific areas are discussed in which variations and differences appear.

Light causes vertebrate visual pigments to bleach, liberating the chromophore. Most invertebrate visual pigments do not bleach in the light, but instead form a thermally stable metarhodopsin, with the chromophore in the all‐trans configuration still attached to the opsin.
In the disk membranes of vertebrate rod and cone outer segments, the rhodopsin molecules are oriented with their chromophores nearly coplanar with the disks. Within this plane, however, both rotational and translational diffusion are possible. In the microvillar membranes of arthropod and cephalopod rhabdoms, on the other hand, the situation is less clear. There is evidence for some preferential orientation of chromophores that implies restrictions on Brownian rotation.
In the outer segments of vertebrate receptors, absorption of light by rhodopsin causes the plasma membrane to hyperpolarize due to a decrease in sodium conductance, possibly mediated by calcium ions. In most invertebrate photoreceptors, light causes a depolarization due to an increase in conductance, principally to sodium ions. A subsequent entry of calcium causes a partial repolarization of the membrane, due to a decrease in sodium conductance.
For vertebrate receptors, log threshold is directly proportional to the fraction of rhodopsin bleached (Dowling‐Rushton relationship). The proportionality constant varies in different preparations from less than four to more than 30, and the physical basis for the relationship is unknown. For invertebrates, by contrast, the dependence of sensitivity on rhodopsin concentration is much less dramatic and may well depend simply on the probability of quantum catch.
In most species, vertebrate and invertebrate, the accumulation of photoproduct probably has no effect on membrane conductance, but several possible exceptions exist.
Photoregeneration of rhodopsin from metarhodopsin is likely an important mechanism of recovery in certain arthropods such as diurnal insects, but dark mechanisms of recovery also exist in all phyla. In no single case are they adequately understood.
How do biological systems discriminate among physically similar ions?
Authors: Diamond Jared M. 
Published: June 2005

AbstractThis paper reviews the history of understanding how biological systems can discriminate so strikingly among physically similar ions, especially alkali cations. Appreciation of qualitative regularities (“permitted sequences”) and quantitative regularities (“selectivity isotherms”) in ion selectivity grew first from studies of ion exchangers and glass electrodes, then of biological systems such as enzymes and cell membranes, and most recently of lipid bilayers doped with model pores and carriers. Discrimination of ions depends on both electrostatic and steric forces. “Black‐box” studies on intact biological membranes have in some cases yielded molecular clues to the structure of the actual biological pores and carriers. Major current problems involve the extraction of these molecules: how to do it, what to do when it is achieved, and how (and if) it is relevant to the central problems of membrane function. Further advances are expected soon from studies of rate barriers within membranes, of voltage‐dependent (“excitable”) conducting channels, and of increasingly complex model systems and biological membranes.
The relation of nerves to multiple regeneration in a single newt limb
Authors: Eiland Lonnie C. 
Published: June 2005

AbstractThree amputation surfaces were formed on the lower arm of a single newt. Growth occurred on all combinations of these surfaces. The proximal surface (the only single surface to form regenerates) produced more regenerates (76% of the cases) than the two more distal surfaces. Blocking the proximal surface with whole skin greatly stimulates the production of accessory structures on the first and/or second more distal surfaces. The mean number of nerve fibers on the proximal surface is considerably higher than the nerve counts of the first more and second most distal surfaces. Limbs possessing a notch or digit(s) on the proximal surface and the absence of growth on the first more and second most distal surfaces also show a decrease in nerve number on the first more and second most distal surfaces. An analysis of the mean number of nerve fibers on the blocked (proximal) surface shows a noticeable decrease in comparison with nerve fibers in an equivalent level on normal limbs. Nerve fiber counts on the first more and second most distal surfaces are markedly increased on those limbs where the proximal surface was blocked with whole skin. Threshold experiments suggest that the irregular occurrence of accessory structures on the first more distal and second most distal surfaces may be related to an insufficient number of nerve fibers on these surfaces. Similarly, a possible explanation for the regular occurrence of accessory structures on the proximal surface is that nerve number on this surface is always above threshold.
Oxygen consumption in the symbiotic hydra Hydra viridis
Authors: Pardy Rosevelt L. , Dieckmann Carole 
Published: June 2005

AbstractOxygen consumption was measured in the algal‐bearing and aposymbiotic hydra, Hydra viridis using a microrespirometer. In the light, green animals exhibited a lower rate of oxygen consumption than green animals in the dark or aposymbiotic animals. Treatment of the algal‐bearing animals with the photosynthetic inhibitor DCMU demonstrated that oxygen produced by symbiotic algae as a result of photosynthesis may supply part of the host's respiratory needs.
Dietary tocopherol and sexual reproduction in the rotifers Brachionus calyciflorus and Asplanchna sieboldi
Authors: Gilbert John J. , Litton James R. 
Published: June 2005

AbstractBrachionus calyciflorus contained no detectable tocopherol (vitamin E) when cultured for long periods on the yeast Rhodutorula glutinis. Using a spectrofluorometric assay and the Asplanchna body‐wall‐outgrowth response bioassay the limits of detection were 6.4 ng and 3.78 pg α‐tocopherol per g dry weight Brachionus, respectively. These tocopherol‐free Brachionus reproduced normally both parthenogenetically and sexually, producing active and potent males and fertilized resting eggs which developed into viable young rotifers. The apparent lack of a tocopherol requirement for male fertility in B. calyciflorus probably also applies to Asplanchna sieboldi and A. brightwelli — rotifers whose male‐producing (mictic) females are induced by dietary tocopherol and whose males therefore are never tocopherol‐deficient. The adaptive significance of the tocopherol requirement for the initiation of sexual reproduction in Asplanchna sieboldi — formerly hypothesized to be the result of a tocopherol requirement for male fertility — is now thought to be related to the role of tocopherol in controlling female polymorphism in this species.
3H‐amino acid uptake and incorporation in sea urchin gastrulae and exogastrulae: An autoradiographic study
Authors: Karp Gerald C. , Weems Marion D. 
Published: June 2005

AbstractAutoradiographic analysis of gastrulae of the sea urchin, Lytechinus pictus, after brief incubation periods with 3H‐amino acids has indicated that the cells of the ectoderm incorporate significantly greater levels of isotope than the cells of the interior. Further analysis based primarily on incorporation patterns of exogastrulae indicate that the greatly lowered incorporation by the cells of the archenteron reflects the inability of small molecular weight precursors to reach the invaginated cells. The maintenance of high levels of 3H‐amino acid incorporation by ectodermal cells of exogastrulae indicates their relative independence with respect to macromolecular metabolism from the cells of the archenteron.
Delayed allatectomy and feeding in phormia regina (MEIG.): Effects on follicular development
Authors: Mjeni A. M. , Morrison P. E. 
Published: June 2005

AbstractA delay in feeding a protein meal to the female blowfly following allatectomy results in inhibition of follicular development in the previtellogenic stage. On the other hand, a protein meal given immediately after the operation permits 55% of the flies to deposit yolk in their oocytes. It is concluded that those flies that do not deposit yolk in their oocytes fail to do so because of the absence of a corpus allatum hormone necessary for the synthesis of vitellogenin.
Biosynthesis of lipovitellin by the crustacean ovary. II. Characterization of and in vitro incorporation of amino acids into the purified subunits
Authors: Lui Chung W. , O'Connor John D. 
Published: June 2005

AbstractThe amino acid composition has been determined for two of the five subunits of the crayfish lipovitellin. In addition the molecular weight of each subunit has also been ascertained. Most importantly it is demonstrated that following in vitro incubation radioactive amino acids are incorporated into each of three purified subunits. These data strongly support the suggestion that the vitellogenic ovary of the crayfish is capable of in situ synthesis of lipovitellin.
Induction of antler growth in a congenitally polled Scottish red deer stag
Authors: Lincoln G. A. , Fletcher T. J. 
Published: June 2005

AbstractA congenitally polled red deer stag was captured from a Scottish deer forest and kept in an enclosure for observations. The animal had rudimentary antler pedicles but no antlers, and during five years of study no significant antler development occurred. Amputation of the apex of one antler pedicle in May 1974 when the stag was 12 years of age resulted in the growth of a complete antler on the operated side, and this antler was subsequently cleaned and cast in the normal way and a new antler cycle was initiated.The result illustrates that the primary abnormality in this polled stag lay not in his inability to grow antlers, but in his inability to develop fully formed antler pedicles from which normal antler tissue could differentiate. Traumatizing the rudimentary pedicle had the effect of stimulating growth of antler tissue, and once this was formed the process of cleaning, casting and regrowth occurred spontaneously. The incomplete development of the antler pedicles is considered to be responsible for the absence of antlers in the majority of “hummels” in Scotland, and the etiology of the condition is discussed.
Mitotic activity and nucleic acid precursor incorporation in denervated and innervated limb stumps of axolotl larvae
Authors: Tassava Roy A. , Mescher Anthony L. 
Published: June 2005

AbstractMitotic activity and DNA and RNA precursor incorporation were compared in innervated regenerating limbs and in denervated, nonregenerating limbs on days 8 and 9 post‐amputation. Innervated limbs had well‐developed cone stage blastemas which showed high cellular mitotic indices and H3‐thymidine labeling indices of 0.40–0.50 and H3‐uridine labeling indices of 0.50–0.75.In contrast, denervated limbs showed dedifferentiated cells distally under thickened wound epithelia, but essentially no mitotic activity and no blastema formation. These dedifferentiated cells showed lower levels of H3‐thymidine (0.10 index) and H3‐uridine (0.50) incorporation than regenerating limbs.Labeling indices of wound epithelia are also compared.
New observations on blood pressure in marine Crustacea
Authors: Belman Bruce W. 
Published: June 2005

AbstractThe pressures that drive blood in the circulatory systems of marine Crustacea are substantially higher than previously supposed. In recordings from the heart of nine species, absolute pressures (mean of systolic and diastolic) range from 6.7 cm‐H2O to 36.0 cm‐H2O. No relationship is apparent between blood pressure in these species and either wet weight or heart rate. It is proposed that the maintenance of high internal pressures may be of functional significance in Crustacea, both in urine formation by ultrafiltration and in molting.
The control of spermatogenesis in the green frog, Rana esculenta
Authors: Rastogi R. K. , Iela L. , Saxena P. K. , Chieffi G. 
Published: June 2005

AbstractThe process of spermatogenesis in Rana esculenta (living in the surroundings of Naples) resurges gradually in the spring months, proceeds actively through the summer and declines gradually in the winter months reaching an almost total “quiescence” for a short length of time. The repeating from year to year with a distinct regularity of spermatogenetic cycle suggests that environmental cues play a role in timing its various phases. Both temperature and photoperiod appear to be potential modifiers of spermatogenetic activity in this species. It is, however, probable that photoperiod acts only in a permissive way to facilitate the temperature response which seems to be the more direct modifier of the testicular activity.The proliferation of primary spermatogonia seems to be favoured by only low temperatures. The formation of secondary spermatogonia, and primary and secondary spermatocytes occurs when there occurs a gradual increase in the ambient temperature, day length and gonadotropin secretion. This period is characterized by very low plasma level of testosterone, that, through the reduced negative feedback to the hypothalamus, favours an increased secretion of FSH‐like gonadotropin. Spermatid formation is entirely androgen‐dependent as confirmed by the use of a specific antiandrogen, cyproterone acetate. In fact spermatid formation naturally occurs in a period when plasma level of testosterone is increasing and pituitary gonadotrops are declining in their secretory activity. In this period the ambient temperature and the photoperiod gradually decline.The importance of lateral eyes and the pineal gland in the mediation of influence of photic cues has been shown. It seems that without either the eyes or the pineal gland both light and temperature are completely ineffective in stimulating the early spermatogenesis, which shows the permissive role of light on temperature influence upon spermatogenesis.Hypophysectomy impairs spermatogenesis, which can be restored by a replacement therapy with homoplastic pituitary extract. Testosterone alone does not restore spermatogenesis except enhancing spermatid formation. Pituitary extract stimulates mitotic activity of spermatogonia and formation of primary and secondary spermatocytes. Testosterone is not involved because the stimulatory effects of pituitary extract are only marginally blocked by the antiandrogen. In fact spermatogonial multiplication is partially inhibited, while spermatid formation is totally blocked, indicating that ICSH‐like gonadotropin acts upon the formation of spermatids through the stimulation of testosterone production.Thus it has been found that there exists a complex interaction between the environmental factors and the “endogenous hormonal trigger” that subsequently steps into the regulation of spermatogenesis.
Gustatory hairs on the mosquito, Culiseta inornata
Authors: Pappas Larry G. , Larsen Joseph R. 
Published: June 2005

AbstractGustatory hairs were investigated on the legs and mouthparts of Culiseta inornata (Williston) (Diptera: Culicidae). One type of hair, each innervated by four neurons, was found on the legs. Two of the neurons responded to NaCl stimulation, one neuron to water stimulation, and one neuron to sucrose stimulation. Three kinds of hairs designated Type 1 (T1), Type 2 (T2) and Type 3 (T3) were analyzed on the labella. The T1 hairs are innervated by one sugar neuron, one mechanoreceptor, two salt neurons and one water neuron. The T2 hairs are innervated by two salt neurons and one mechanoreceptor. The T3 hairs, located on the oral surface of the labella, are innervated by a variable number (2‐5) of neurons. Precise identification of the T3 chemosensory neurons was not made because of the small size and inaccessibility of the T3 hairs. Chemosensory hairs on the tip of the labrum were tested electrophysiologically. The sequence of decreasing effectiveness for the three salts tested was KCl > NaCl > LiCl. Labral chemoreceptors also responded positively to sucrose.
Regional differences between nuclear concentration of (3H) estradiol and (3H) progesterone and their action on the uterus of rat during delayed implantation
Authors: Prasad M. R. N. , Sar M. , Stumpf W. E. 
Published: June 2005

AbstractThe cellular and subcellular localization of radioactivity by drymount autoradiography was studied at 5, 15 and 30 minutes after intraluminal or at 5, 15 and 60 minutes after subcutaneous administration of (3H) estradiol or (3H) progesterone to rats in which implantation was delayed by ovariectomy on day 3 post‐coitum, followed by treatment with progesterone. After intraluminal instillation of (3H) estradiol or (3H) progesterone, radioactivity was cleared from the uterine lumen at 5 minutes. After intraluminal as well as subcutaneous injection of (3H) estradiol, radioactivity was concentrated at all time intervals in the nuclei of cells of the substantia propria, glands and muscularis, but not in the luminal epithelium. White blood cells and endothelial cells were unlabeled, while perivascular cells showed concentration of radioactivity.After intraluminal instillation of (3H) progesterone, radioactivity was retained in the cytoplasm of the luminal epithelium at 5 and 15 minutes, while no such concentration appeared after subcutaneous injection. No selective nuclear retention was observed in the luminal epithelium, in contrast to the substantia propria and muscularis.The autoradiographic results indicate that progesterone treatment simulating the conditions of early pregnancy, changes the uptake affinity of uterine tissues for (3H) estradiol. The lack of a detectable concentration of estrogen within nuclei of the luminal epithelium does not preclude hormone action. Possible mechanisms of metabolic activation of the uterine luminal epithelium in the apparent absence of concentration of (3H) estradiol to nuclei of the luminal epithelium are discussed.
Effects of seasonal and social factors on testicular activity and hormone levels in domestic pigeons
Authors: Haase E. , Paulke E. , Sharp P. J. 
Published: June 2005

AbstractTesticular morphology and plasma concentrations of luteinizing hormone (LH), testosterone, progesterone, and estradiol‐17βT were compared in paired (n = 8) and unpaired (n = 7) racing pigeons killed in December. The birds were housed mixed together under natural lighting conditions in two unheated lofts which contained no nesting facilities, in Kiel (54°N), Germany. The paired birds had been paired for at least two months. Testicular weights and diameters of tubules were significantly higher (p < 0.05) in paired (1.64 ± 0.25 gm; 218 ± 12 μm) than in unpaired birds (0.79 ± 0.25 gm; 165 ± 20 μm). The testes of paired birds were spermatogenetically more active than those of unpaired birds. Plasma concentrations of some hormones concerned with reproduction were, in paired and unpaired birds respectively: LH, 2.28 ± 0.43 ng/ml and 0.98 ± 0.36 ng/ml (significantly different, p < 0.1); testosterone, 1.24 ± 0.51 ng/ml and 0.59 ± 0.12 ng/ml (not significantly different); progesterone, 0.58 ± 0.08 ng/ml and 0.90 ± 0.12 ng/ml (significantly different, p < 0.05); and estradiol‐17βT, 16.3 ± 0.95 pg/ml and 18.7 ± 2.25 pg/ml (not significantly different). Thus, the stimulatory effects of a mate on gonadotropin secretion and gonadal activity which have often been reported for female ring doves and domestic pigeons are also demonstrable in males during the late fall. Seasonal testicular regression in the unpaired males at this time of year was not prevented by the presence of paired females.
How X‐rays inhibit amphibian limb regeneration
Authors: Maden M. , Wallace H. 
Published: June 2005

AbstractThe effects of an inhibiting dose of 2,000 rad of X‐rays on the regenerating limbs of axolotl larvae have been examined in a histological and cytological study. Particular attention was paid to the mitotic indices of normal and irradiated epidermal and blastemal cells. Both the characteristic pattern of epidermal mitotic stimulation which normally follows amputation and the later increase in blastemal mitoses are suppressed by irradiation. In most cells the effects are permanent, but in a small proportion a mitotic delay is induced and upon subsequent division chromosome damage in the form of micronuclei is revealed. Thus irradiated cells which do divide almost certainly die. These results are discussed in relation to other theories of X‐ray inhibition of regeneration with particular reference to the view that irradiated cells can be reactivated.
The development of regional pigmentation patterns in black and tan (at) Mice
Authors: Poole Timothy W. , Silvers Willys K. 
Published: June 2005

AbstractMice which express the black and tan (at) allele at the agouti locus have black dorsal and yellow ventral hairs. To determine the site of action of this allele, the kind of hair pigment produced by various dermal‐epidermal recombinations of dorsal and ventral black and tan (at / at), ventral nonagouti (at / at) and ventral yellow (Ay / a) embryonic skin has been investigated. The results indicate that it is the dermis which is responsible for the development of regional pigmentation patterns in black and tan mice.
Sperm proteinase release during fertilization of rabbit ova
Authors: Stambaugh Richard , Smith Monica 
Published: June 2005

AbstractProteinase activity was found to be present along the sides of sperm penetration tunnels through the zonae pellucidae of rabbit ova using silver‐proteinate staining techniques. This is the first direct confirmation of the generally accepted concept of sperm penetration by proteinase release and digestion of the zona pellucida.