bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermoacclimatory response of nucleic acid and protein content of carp muscle tissue: influence of growth rate and relationship to glycine uptake by scales
Authors: Goolish Edward M. , Barron Mace G. , Adelman Ira R.
Published: December 2009

RNA concentration in carp (Cyprinus carpio) white muscle tissue increased with higher growth rate for all acclimation temperatures, while DNA, protein content, and tissue hydration were unaffected. For a given growth rate, RNA concentration per unit tissue weight and per unit DNA (RNA per cell) was higher in colder acclimated fish as a probable compensation for decreased RNA activity. Maximum growth resulted in an approximate doubling of the RNA/DNA ratio while, over the range of 12–30 °C, cold acclimation caused an increase of approximately 50%. Changes in DNA concentration and protein/DNA ratios at different acclimation temperatures indicated an increase in cell mass with warmer acclimation temperatures. Muscle RNA/DNA ratios and the rate of glycine uptake by scales were highly correlated. Regression equations describing this relationship for each acclimation temperature were not significantly different when scales were incubated at each fish's acclimation temperature, but were significantly different when glycine uptake was expressed for incubation at the temperature of maximum uptake. These results suggest a whole-body integration between thermoacclimatory changes in the RNA component of muscle protein synthesis and in the rate of amino acid transport by scales.
The influence of low pH environments on ion regulation in the larval stages of the anuran amphibian, Rana clamitans
Authors: McDonald D. G. , Ozog J. L. , Simons B. P.
Published: December 2009

Epithelial ion regulation by larval Rana clamitans (developmental stages III to XX) and early stage juveniles (stage XXV) was examined in soft water (Ca2+ = 300 μequiv./L) at circumneutral pH and during exposure to low pH (nominally 4.0). In tadpoles and juveniles, the acute acid exposure initially caused substantial increases in transepithelial net ion losses and in net acid uptake, and a slight inhibition of active ion transport. In tadpoles, these disturbances had largely disappeared by 7 h of acid exposure but they persisted in early stage juveniles with no apparent sign of recovery. Prior acclimation of tadpoles to a sublethal pH (12 days at pH 5.0) did not reduce the ionoregulatory disturbance at pH 4.0 and the acclimated animals were less able to restore those losses at circumneutral pH compared with a control group. It is concluded that larval amphibians show many similarities with fish in ionoregulatory responses to acid exposure including an inability to adapt to low pH, but the magnitude and duration of disturbances are generally less. This suggests that larval amphibians may be more able to resist acid exposure than many acid-intolerant fish species such as the salmonids.
Changes in cell number and activity of the corpora allata of the cockroach Diploptera punctata: a role for mating and the ovary
Authors: Tobe S. S. , Clarke N. , Stay B. , Ruegg R. P.
Published: December 2009

The corpora allata (CA) of mated female Diploptera punctata showed an increase in cell number from 6000 cells/CA on the day of emergence to a maximum of about 9000 cells/CA by day 5. The number of cells per CA then declined and, by day 8, the CA was composed of about 6000 cells. In the normal mated animal, the previously established increase in biosynthetic activity of the CA correlated with the increase in number of cells in the CA. In virgin females no significant change in cell number was observed during this period and this correlates with the demonstrated low and constant rates of juvenile hormone (JH) biosynthesis. Following ovariectomy, however, an increase in cell number occurred (to 10 000 cells/CA) by day 5 and cell number remained elevated until at least day 8. Low rates of JH biosynthesis have been observed previously in ovariectomized females and thus the increase in cell number observed in these females is not accompanied by a corresponding increase in biosynthetic activity. The cell number of the CA in ovariectomized females was reduced by injection of 20-hydroxyecdysone. We propose that either mating or surgical removal of inhibitory signals from cerebral neurosecretory cells permits the proliferation of the cells of the CA. We also propose that factors from the ovary are responsible for both the initiation of the cycle of JH biosynthesis and the reduction of CA cell number at the end of the gonotrophic cycle.
Delay of gametogenesis and spawning by constant illumination of rainbow trout (Salmo gairdneri) during the first reproductive cycle
Authors: Bourlier A. , Billard R.
Published: December 2009

Two-year-old, 500–600 g immature and prepuberal male and female rainbow trout were exposed on June 21 to continuous light (CL group) or, as a control, to the natural photoperiod in the Paris area (C group) and were kept under seasonal variation of temperature. Gametogenesis was studied by periodic sampling of the gonads for quantitative analysis of spermatogenesis and measurement of follicle diameter. Gonadotropin (GTH) profiles were measured in pituitary and plasma by radioimmunoassay. During spawning, the quantity and quality of gametes were measured. Under continuous light, gametogenesis and spawning were delayed by about 2 months as compared with the controls kept under a natural photoperiod. Delayed gametogenesis in the fish under continuous light showed some alterations. In the males, the dynamics of spermatogenesis was modified since the proportion of the germ cells in the testis was changed as compared with the controls; e.g., spermatids were present in the testicular lobules when spermiation started. The yield of spermiation measured in four samplings was lower in males under continuous light as compared with the controls. In the females, follicle diameter and gonadosomatic index tended to remain lower during vitellogenesis in the CL group as compared with the C group, but finally, the diameter of the eggs stripped and the fecundity were not different in both groups. GTH profiles were different only for the plasma in December. The pituitary GTH content was low in December in both groups and sexes, irrespective of the stage of the reproductive cycle and of the light environment. There was no difference in hepatosomatic and viscerosomatic indices between the two groups.
Selection of foraging sites and invertebrate prey by migrant Semipalmated Sandpipers, Calidris pusilla (Pallas), in Minas Basin, Bay of Fundy
Authors: Hicklin Peter W. , Smith P. C.
Published: December 2009

We determined the particle size composition of substrates, the species composition and abundances of mud-dwelling invertebrates, and the distribution, densities, and diets of Semipalmated Sandpipers foraging on different mud flats in Minas Basin, Bay of Fundy, during the birds' southward migration. Substrate types varied between the mud flats used by shorebirds; particle sizes ranged from sandy (coarse to fine sands) to muddy (mainly silt and clay). Of 34 species of invertebrates identified, the polychaetes Spiophanes bombyx (Clarapede) and Heteromastus filiformis (Clarapede) and the amphipod Corophium volutator (Pallas) were the most numerous and widely distributed. Spiophanes and the "bamboo" worm Clymenella torquata (Leidy) were more abundant in coarse sandy substrates whereas numbers of Heteromastus were negatively correlated with grain size. The densities of Corophium were positively correlated with the amount of very fine sand in the substrate. The sandpipers foraged in larger numbers on mud flats where densities of Corophium were greatest and it was the main prey taken at those sites. The birds' diet was more diverse in areas of low Corophium density. It appears that the birds use visual cues for foraging and that prey behavior is particularly important in their choice of prey items.
Sex ratios of two species of sea turtle nesting in Suriname
Authors: Mrosovsky N. , Dutton P. H. , Whitmore C. P.
Published: December 2009

The green turtle (Chelonia mydas) and the leatherback (Dermochelys coriacea) nest on the same beach in Suriname. For both species there are seasonal changes in the sex ratio of the hatchlings, with more males being produced during the wetter cooler months of the nesting season and more females during the drier warmer months. This shows that temperature determination of sexual differentiation has considerable demographic consequences in natural circumstances. Leatherbacks require slightly higher (ca. 0.5 °C) temperatures for female differentiation than green turtles and leatherbacks nest in relatively greater numbers during the warmer parts of the season. Estimates of overall sex ratio for hatchling green turtles (53.9% female) and for leatherbacks (49.0% female) were obtained by multiplying sex ratio and nesting frequency for different portions of the season. These estimates are tentative because there were differences between different years both in sand temperatures on the beach and in nesting distribution. Also discussed are the problems in assessing parental investment in the two sexes when the direction of sexual differentiation is determined after parental investment ends.
Proximate composition of the river lamprey, Lampetra fluviatilis, during the spawning run
Authors: Heikkala R. M. , Laukkanen A. T. , Mikkonen A. V.
Published: December 2009

The composition of the muscle, liver, and gonads of adult river lampreys (Lampetra fluviatilis L.) was studied in northern Finland from the beginning of the spawning run in August–September until the end of the spawning season in late May or early June of the following spring. During the spawning run period, which may last for9–10 months, lampreys spend 6 months in water with a temperature around 0 °C. These harsh physical circumstances only have remarkable delaying or economizing effects on the results when compared with findings on lampreys with a shorter spawning run. The locomotor activity of the lamprey was very minor during the winter, and so it did not need greater than 10–15% wet weight (w.w.) muscular lipid reserves as an energy source for swimming. The gonads were well developed; i.e., the gonadosomic index was 5% in males and 11% in females at the beginning of the spawning run (9 and 26%, respectively, during the spawning time) and, as a result, the lipid concentration of liver, where vitellogenesis takes place, was not greater than 15% w.w. in males and 5% w.w. in females. Our results suggested that after wintering in the northernmost parts of the species' range, river lampreys were prepared for the rapid start of spawning in the spring, as soon as the water temperature was appropriate.
Ecology and evolution of sympatric sticklebacks (Gasterosteus): specialization for alternative trophic niches in the Enos Lake species pair
Authors: Bentzen P. , McPhail J. D.
Published: December 2009

Two morphologically distinct species of threespine stickleback (Gasterosteus) coexist in Enos Lake on Vancouver Island. For convenience these species are referred to as "limnetics" and "benthics." We used three experiments to compare the feeding performance of the two species and to test the hypothesis that limnetics are adapted for planktivory whereas benthics are adapted to forage on substrates. The results support this conclusion. When tested for maximum prey size; benthics consumed larger prey (relative to their body size) than limnetics. Benthics also were more successful than limnetics in foraging on a substrate. When allowed to forage for a fixed time on a detritus substrate, benthics of both sexes captured more prey than male limnetics, even though male limnetics directed as many feeding strikes at the substrate as did the benthics. Female limnetics would not forage on a detritus substrate. Limnetics were more successful in feeding on plankton than benthics. When held in mesh enclosures suspended in Enos Lake, limnetics consumed more plankton than benthics. Small limnetics (26–36 mm standard length) consumed nearly four times more plankton than large limnetics (44–50 mm standard length). The small limnetics were all either mature females or immature males; the large limnetics were all mature males. The results of the benthic foraging and plankton feeding comparisons support the additional conclusion that Enos Lake limnetics are sexually dimorphic in their feeding behaviour.
Succession des communautés de gastéropodes dans deux milieux différant par leur degré d'eutrophisation
Authors: Legendre P. , Planas D. , Auclair M.-J.
Published: December 2009

This paper compares the succession of gastropods in two environments that are adjacent in space but differ as to their eutrophic level. One is hypereutrophic (du Sud River), the other is mesotrophic (Richelieu River). Canonical correlation analysis brings out the main differences between these two stations, while principal component analysis is used to describe the succession of species within each community. These analyses indicate that the occurrence of gastropod species, as well as their development cycles, may be adapted to the particular synecological evolution of each environment. Thus, the species would not react directly to nutrient concentrations but indirectly, through the effects of these concentrations on oxygen content, plant cover, and predators. In these two environments, some benthic species seem to be good indicators of the eutrophic level of the ecosystem.
Paragyptis margaretae, new genus and species of Hesionidae (Annelida: Polychaeta) from St. Margaret's Bay, Nova Scotia
Authors: Pocklington Patricia
Published: December 2009

Paragyptis margaretae n.g., n.sp. is described from St. Margaret's Bay, Nova Scotia. It is the only genus of the family Hesionidae with eight pairs of tentacular cirri, two antennae, and strongly biramous parapodia. Its relationship to other members of the family is discussed.
The influence of the physical, chemical, and microbiological characteristics of decomposing leaves on the growth of the detritivore Tipula abdominalis (Diptera: Tipulidae)
Authors: Lawson Daniel L. , Klug Michael J. , Merritt Richard W.
Published: December 2009

This study investigated the effects of changes in the physical, chemical, and microbiological characteristics of decomposing pignut hickory (Carya glabra) leaves on the consumption rate, assimilation efficiency, and growth rate of the detritivore Tipula abdominalis. Larval growth was highest on leaves that had undergone decomposition for intermediate time periods. During this period maximum concentrations in leaf nitrogen, microbial biomass (ATP), and changes in microbial community structure associated with the decomposing leaves were observed. Laboratory feeding studies that investigated the role of these factors on larval growth established that microbial biomass, estimated by 15N enrichment, and leaf nitrogen concentration did not influence larval growth. However, microbial community structure had a significant influence on T. abdominalis consumption rate, assimilation efficiency, and growth rate. Results suggest that for normal growth T. abdominalis requires a microbial community composed of at least fungi and bacteria within its diet, but for reasons other than as a direct source of carbon and nitrogen.
Experimental study on the role of intra- and inter-specific competition in the evolution of nest-destroying behavior in marsh wrens
Authors: Picman Jaroslav
Published: December 2009

Marsh wrens attack nests with eggs and young of other birds, including conspecifics. This study examined the relative role of interference from conspecifics and red-winged blackbirds in the evolution of the marsh wren nest-destroying behavior by giving male wrens a choice to attack a redwing or marsh wren nest. The combined data on wren responses from 4 years showed that male marsh wrens exhibited stronger responses to redwing than to wren nests, which suggests that in the study area the interference from blackbirds is usually more important than that from other marsh wrens. However, the between-year analysis, relating the intensity of marsh wren responses to nests of the two species to the intensity of intra- and inter-specific interference, indicated that marsh wrens adjust their responses to the prevailing type of interference. Thus marsh wrens attacked the redwing nest first when interspecific interference was more important, but their resonses to the wren nest became stronger with increasing intraspecific interference. These data support the idea that intense intraspecific competition as well as the interference from blackbirds have played an important role in the evolution of nest-destroying behavior by marsh wrens.
Comparative tolerance to low pH of three life stages of the crayfish Orconectes virilis
Authors: France R. L.
Published: December 2009

The response of three life cycle stages of Orconectes virilis to acidification was investigated in the laboratory. Chronic lethality tests revealed that compared with 2-week-old stage III hatchlings, 2.5-month-old juveniles were seven times more tolerant to acid but only one-twentieth as tolerant as 2- to 3-year-old adults. Juvenile crayfish recovered following exposure to acid stress (pH < 3.5). Comparison of laboratory survival results with data from the literature concerning the magnitude and duration of chemical fluctuations indicates that lentic populations of O. virilis are not likely to decline as a result of episodic acid events. Nevertheless, gradual acidification of a lake to an average annual pH below 5.5 could result in eventual population extinction as a result of mortality of the young.
Secretion and absorption of nutrients in the alimentary tract of reindeer fed lichens or concentrates during the winter
Authors: White R. G. , Jacobsen E. , Staaland H.
Published: December 2009

Water, organic matter (OM), N, Ca, P, K, Na, and Cl exchange was estimated in the alimentary tract of reindeer given concentrate or lichen diets alone or supplemented with minerals. Chromic oxide was used as a nondigestible marker and results are discussed in relation to inaccuracies of this marker technique. The pattern of water, OM, and N exchange was similar to other ruminants; over 61% of OM digestion was due to the rumen–reticulum plus omasum and abomasum (stomachs). For the concentrate diet, 40–60% of N digestion occurred in the stomachs. Apparent absorption of Ca, P, and Mg in the stomachs was linearly related to intake. Ca and Mg supplemented to lichens was excreted because of an inability of the intestines to recover mineral secreted into duodenal contents. In contrast, the jejunum absorbed P added to the diet. Excretion of K in feces at 0.076 mM/g fecal dry matter placed a limit on K absorption; it was negative on the lichen diet. Cl was absorbed in the small and large intestines. Supplemental Na, part of the P, Ca, and K, but none of the supplemental Mg added to the lichen diet was absorbed. Lichens appeared to bind some minerals and could thereby place a limit on their absorption.
Relationships of maternal–fetal plasma steroid and amniotic fluid electrolyte levels to uterine myoelectrical activity during late gestation in sheep
Authors: Kitts D. D. , Krishnamurti C. R.
Published: December 2009

Paired bipolar electrodes were implanted in the corpus and uterotubal junctions in pregnant ewes. The temporal changes in uterine myoelectrical activity were monitored in conjunction with maternal and fetal plasma steroid and amniotic fluid electrolytes to evaluate the mechanisms regulating the prepartal uterine contractions in the ewe. Increases in total uterine myoelectrical activity were significant (P < 0.001) at both uterine locations as term approached, although significant (P < 0.01) variation existed between individual animals. Significant correlations between maternal progesterone (P < 0.05) and maternal and fetal estrogens (P < 0.01) and uterine myoelectrical activity were observed. The decline in maternal progesterone to levels of 2.03 ± 0.4 ng/mL and concomitant increases in both maternal and fetal total estrogens (199.3 ± 4.7 and 262.5 ± 11.0 pg/mL, respectively) resulted in a relatively high maternal estrogen/progesterone ratio just prior to parturition and corresponded to an approximate fivefold increase in total uterine electrical activity. Fetal cortisol concentrations were not significantly correlated with uterine myoelectrical activity; however, a positive correlation (P < 0.05) between fetal cortisol and maternal estrogen/progesterone ratios was obtained. The results of this study demonstrate a direct relationship between changes in the maternal estrogen/progesterone ratios and frequency and patterns of uterine electrical signals just prior to parturition, which may be ultimately triggered by the surge in fetal corticosteroid production.
Tissue regeneration in the amputated forelimb of Xenopus laevis froglets
Authors: Korneluk Robert G. , Liversage Richard A.
Published: December 2009

The present study directly compares the response of amputated forelimbs in Xenopus laevis froglets with epimorphic regeneration of forelimbs in adult newts (Notophthalmus viridescens). Epidermal wound healing was initiated following limb amputation in both froglets and newts. Dedifferentiation of mesodermal stump tissues was comparatively extensive in the regenerating newt limb, whereas Xenopus forelimbs underwent little if any tissue dedifferentiation. Blastema accumulation and growth are prominent features of newt forelimb regeneration. In contrast, only a small fibroblastlike cell accumulation was observed at the distal tip of the Xenopus limbs. Differentiation of blastemal cells in the urodele limb was delayed until extensive blastema growth was achieved, whereas differentiation was immediate in Xenopus. Morphogenesis of the regenerative outgrowth in Xenopus was limited to the differentiation of connective tissue elements, primarily cartilage. In contrast, complete regeneration of all limb tissues occurred in newt forelimbs. We conclude from our findings that a dominant tissue regenerative response exists following forelimb amputation in Xenopus froglets, whereas epimorphic regeneration prevails in the amputated adult newt limb.
Modification of the hydric environment by eggs of snapping turtles (Chelydra serpentina)
Authors: Gutzke William H. N.
Published: December 2009

Flexible-shelled eggs of snapping turtles (Chelydra serpentina) incubated on a dry substrate in the laboratory lost sufficient water to cause the water potential of their environment to increase significantly. This modification of the hydric environment prevented eggs from becoming desiccated and demonstrated the capacity of reptilian eggs to modify their environment in such a manner as to enhance their likelihood of completing development.
Energy budget for a stream population of the freshwater clam, Sphaerium striatinum Lamarck (Bivalvia: Pisidiidae)
Authors: Hornbach Daniel J. , Wissing Thomas E. , Burky Albert J.
Published: December 2009

An annual energy budget was constructed for a stream population of Sphaerium striatinum. The annual productivity (P) was 2.79 g C∙m−2∙year−1 and the average standing crop biomass (B) was 0.58 g C∙m−2; the resulting annual P:B ratio of 4.58 is below that expected for a bivoltine animal. The low value for reproductive effort (Re:P = 16.1%) may partially be attributed to the ovoviviparous, iteroparous nature of this population. A strategy of partitioning a large proportion of production to growth (G:P = 83.9%) may insure a high probability of attaining the minimum size necessary for reproduction. Production accounts for 44% of assimilation (A) with 56% of A lost through respiration. The net production efficiency (P:A = 44%) is high and indicates that this population is efficient in partitioning energy to growth and reproduction. The population must consume (C) 10.57 g C∙m−2∙year−1 to meet its energy needs. Only 35% of this could be accounted for by filter feeding; the remainder may have come from deposit feeding. Comparisons of P, P:B, Re:P and P:A with published values for corbiculacean clams indicates that this population of S. striatinum is one of the most productive and efficient in its energy partitioning of populations studied to date.
Trappability estimates for mark–recapture data
Authors: Krebs Charles J. , Boonstra Rudy
Published: December 2009

Mark–recapture methods produce more accurate estimates when a high fraction of the population is trapped. Three estimates of trappability are used in the literature, and we compare them for four species of Microtus livetrapped in Longworth traps. The trappable population is defined by the weight at first capture and varies greatly in different species. Jolly trappability is the best estimate of trappability and is on average 4% above minimum trappability and 8% below maximum trappability. Trappability in Microtus varies seasonally, is lowest in summer, and may be reduced at high densities. Females are, on the average, 2% more trappable than males. Trappability is the same in fenced and unfenced populations and is highly consistent in different populations of the same species. Comparisons between different population studies or trapping techniques should utilize the Jolly trappability measure and recognize that it will usually have a positive bias if capture probabilities are heterogeneous. Minimum trappability is a good second choice.
Structure of the conus arteriosus and ventral aorta in the sea lamprey, Petromyzon marinus, and the Atlantic hagfish, Myxine glutinosa: microfibrils, a major component
Authors: Wright Glenda M.
Published: December 2009

Light and electron microscopic observations of the conus arteriosus (CA) and ventral aorta (VA) of the sea lamprey, Petromyzon marinus, and the Atlantic hagfish, Myxine glutinosa, reveal the presence of a unique form of fibrous extracellular matrix within their media and an unusual type of connective tissue forming the lateral subendothelial distensions found only in the lamprey CA. The extracellular matrix of the media in lamprey and hagfish CA and VA is characterized by large concentrations of tubular, elastic fibrelike microfibrils 11–17 nm in diameter. No elastic fibrelike elastin component could be found. Collagen fibrils, matrix granules, and intergranular filaments make up the remainder of the matrix. The loose connective tissue composing the lateral distensions of the larval and adult lamprey CA contains ultrastructural features similar to those of lamprey mucocartilage. It is speculated that since lampreys and hagfish are living representatives of the most primitive group of vertebrates, the microfibrils present in their major arteries may represent a primitive form of elastic fibre in which elastin has not yet developed. The functional significance of the extracellular microfibrils in the CA and VA of lamprey and hagfish and the occurrence of lateral distensions in the lamprey CA are discussed.
Morphologie externe et pigmentation du dauphin de Commerson, Cephalorhynchus commersonii (Lacépède, 1804), en particulier celui des îles Kerguelen
Authors: Robineau Daniel
Published: December 2009

Accurate data on the external morphology and color pattern of Commerson's dolphin (Cephalorhynchus commersonii) off the Kerguelen Islands were obtained by studying 11 individuals. The total length of the animals is 142,6 to 174 cm and their weight ranges between 55 and 86 kg. Their coloration is black, grey, and white; a sexual dimorphism exists in the form of genital patches. As far as I know, these dolphins are much bigger and heavier than South American specimens. Their coloration also differs from the typically black and white pattern of the latter. These characteristics suggest that the Kerguelen Islands population is isolated from the main stock of the species.
Morphometric study of the cochlea of the rabbit (Oryctulagus cuniculus)
Authors: Ramprashad Fred , Landolt Jack P. , Money Kenneth E. , Laufer Jerry
Published: December 2009

A detailed morphometric study of the cochleae in four rabbits (Oryctulagus cuniculus) was made from graphic reconstructions of serial sections. Morphometric changes studied along the length of the cochlea were (i) the cross-sectional areas of the scalae vestibuli, tympani, and media, (ii) the width of the basilar membrane, (iii) the cross-sectional area and thickness of the basilar membrane, and (iv) the density of the bipolar ganglion cells innervating the organ of Corti. Changes in the cross-sectional areas of the scalae tympani and vestibuli were similar, both decrease from the cochlear base to 1.2 mm, increase to maximum values of 1.4 mm2 at 3.0 mm, and decrease to 0.4 mm2 at 4.3 mm. The cross-sectional area of the scala media remained unchanged. Three distinct morphometric changes were observed in the width and cross-sectional area of the basilar membrane. Firstly, there is a steep increase from the basal end to 3.2 mm, secondly a gradual increase from 3.2 to 8.5 mm, and thirdly, the greatest values occurred between 8.5 and 9.1 mm. The average number of bipolar ganglion cells estimated within the spiral ganglion was 26 700. The density of ganglion cells decreased from the base to 1.9 mm and then increased to its greatest density of 2800 cells/mm2 between 8.5 and 10.5 mm. The location of maximum density coincided with the location of the basilar membrane where the stiffness gradient was relatively uniform.
Renal portal phagocytosis of bacteria in rainbow trout (Salmo gairdneri Richardson): ultrastructural observations
Authors: Ferguson H. W.
Published: December 2009

Catheterized rainbow trout (Salmo gairdneri) were inoculated with killed bacteria and the perfused – fixed kidney was examined in the electron microscope. The endothelium of the portal circulation was continuous but had evidence of marked pinocytotic activity with large numbers of intracytoplasmic vesicles, many of which were spiny coated. Intracytoplasmic transfer tubules were also a prominent feature. Bacteria were phagocytosed by macrophages closely associated with the endothelium, but not by the endothelial cells. Macrophage pseudopodia were occasionally seen traversing endothelium to touch the underlying haemopoietic tissue. The renal portal vasculature provides a large area for efficient antigen trapping.
Revision of the genus Viktorocara Guschanskaya, 1950 (Nematoda: Acuarioidea)
Authors: Wong P. L. , Lankester M. W.
Published: December 2009

Four species of Viktorocara Guschanskaya, 1950 are considered valid: (1) V. capillaris (Molin, 1860b) Wong and Lankester, 1984, designated the type species because the previous one, V. schejkini Guschanskaya, 1950, is considered its synonym; (2) V. limosae Daiya, 1966 with V. numenii Petter, 1967 and V. torea Clark. 1978 as its new synonyms; (3) V. garridoi Barus, 1968; and (4) V. charadrii Belopolskaya, 1953 with V. guschanskoi Leonov, 1958 as its new synonym. Viktorocara aulieatina is regarded as a species inquirenda. Lastly, V. acholonui Schmidt and Kuntz, 1972 is transferred to Ancyracanthopsis, thus becoming Ancyracanthopsis acholonui (Schmidt and Kuntz, 1972) n. comb. Viktorocara capillaris and V. limosae Daiya, 1966 are redescribed. Schistogendra Chabaud and Rousselot, 1956 is considered a synonym of Quasithelazia Maplestone, 1932. This genus now consists of three species: Quasithelazia tenuis Maplestone, 1932, Quasithelazia incisa (Chabaud and Rousselot, 1956) n. comb., and Quasithelazia caprona (Bain and Chabaud, 1965) n. comb.
The biochemical composition of fin whale blubber
Authors: Lockyer C. H. , McConnell L. C. , Waters T. D.
Published: December 2009

Fin whale blubber is a heterogenous tissue containing 8.9–77.4% lipid, 3.1–33.8% protein, and 0.07–0.73% ash by wet weight. The blubber may be subdivided into three macroscopically distinct zones. The outermost zones contain up to twice the lipid content of the innermost zone adjacent to the muscle, which contains more protein. Anterior ventral blubber contains less lipid, more protein (of which 50% is collagen), and more ash than posterior dorsal blubber. Foetal blubber contains 1.2% lipid, 10.6% protein, and 0.93% ash by wet weight. Blubber lipid contains ca. 60% triacylglycerol and ca. 25–30% free fatty acid, compared with ca. 25% triacylglycerol and ca. 10% free fatty acid in foetal blubber lipid, which also contains ca. 40% phospholipid. The high free fatty acid component is certainly partly due to postmortem hydrolysis in samples analysed. Monounsaturated fatty acids comprise ca. 60% of blubber lipid; 16:0, 16:1, 18:1, 20:1, 22:1, and 22:6 predominate, similar to the dietary intake. The predominant fatty acids in the outermost and the innermost blubber zones are 22:1 and 16:0, respectively. This may have significance in energy storage and catabolic breakdown.
Evidence for pregnancy failure in young female Lemmus lemmus and Microtus oeconomus
Authors: Jensen Per Magne , Gustafsson Torgny O.
Published: December 2009

Pregnancy success in wild Norwegian lemming, Lemmus lemmus, and root voles, Microtus oeconomus, was monitored by recording the occurrence and condition of copulatory plugs, embryos, and mammae in ear-tagged females, which were recaptured several times throughout the summer of 1981 at Finse, Norway. Both populations increased and peaked in density during this period and evidence of pregnancy failure was found in several young, nulliparous females of both species. Similar observations have been reported in several other microtine species and the results are discussed in relation to (i) infertility of immature females, (ii) pregnancy block caused by unfamiliar males, and (iii) other stress related phenomena.
Grizzly bear digging sites for Hedysarum sulphurescens roots in southwestern Alberta
Authors: Holcroft Anne C. , Herrero Stephen
Published: December 2009

Characteristics of sites where Hedysarum sulphurescens Rydb. roots were extensively, less extensively, or not dug by grizzly bears Ursus arctos horribilis Ord. were analyzed in relation to topographic, vegetative, soil, and geologic features. Discriminant function analysis significantly separated dug and undug sites, but did not separate extensively and less extensively dug sites. Ease of breaking the soil surface, presence of shaly rock fragments, loose cobble and gravel, and steep slopes were characteristic of dug sites. The abundance of H. sulphurescens appeared less important than the loose nature of the substrate indicating that digging time was important in optimizing energetics.
Caloric reserves in natural populations of a blackfly, Simulium decorum (Diptera: Simuliidae), and a deerfly, Chrysops ater (Diptera: Tabanidae)
Authors: Magnarelli Louis A. , Burger John F.
Published: December 2009

Simulium decorum and Chrysops ater immatures were collected in northern New Hampshire during 1982 and were reared to adults in the laboratory to describe follicular development, to quantify total available caloric reserves, and to determine longevity. Females of both species produced eggs without blood meals and sucrose solutions during the first ovarian cycle. Differences in mean fecundity (mean range, 152–215) were noted for the Chrysops obtained at three sites below a trout-rearing pond. A chemical test consisting of a sulfuric acid solution of sodium bichromate was used to quantify caloric reserves in the newly emerged blackflies and deerflies. Available reserves for S. decorum females, ≤4 h or 24 h after eclosion, were about sevenfold greater than those of the males. There were no significant differences in available reserves for adult deerflies. Although males and females of both species utilized stored reserves for survival during early adulthood, sugars greatly enhanced longevity.
Social organization of sea otters in Prince William Sound, Alaska
Authors: Garshelis David L. , Johnson Ancel M. , Garshelis Judith A.
Published: December 2009

Sea otters in Prince William Sound. Alaska, were spatially segregated into predominantly (97%) male areas at the front of the expanding population and breeding areas with fewer (up to 33%) males. From 1975 to 1984 we captured and marked 267 otters with tags and (or) radio transmitters and investigated their reproductive strategies, social relationships, and patterns of sexual segregation. Mating occurred year-round, but peaked in September and October. Females first bred at 4 years of age and were capable of pupping annually; they generally separated from their pup before mating. Males established breeding territories that enabled prolonged precopulatory interactions that may have prompted female–pup separation and post-copulatory interactions that precluded females from mating with other males. Male mating success was related to age, weight, territory quality, and the length of time they maintained their territory. After the breeding season, territorial males returned to male areas where food was more abundant. Young, dispersing males also entered male areas and remained there until attaining breeding age. In male areas, otters commonly rested in groups of >50 individuals. Gregariousness promoted social interactions and likely enhanced food finding and (historically) predator protection. As food diminished, males moved into adjacent, unoccupied regions; females then occupied former male areas.
Diurnal periodicity of plasma Cortisol and corticosterone in desert bighorn sheep demonstrated by radioimmunoassay
Authors: Turner Jack C.
Published: December 2009

A sensitive and specific radioimmunoassay (RIA) for Cortisol and corticosterone was validated for desert bighorn sheep (Oviscanadensis cremnobates) plasma. Statistical and physiological validation of assay accuracy, precision, sensitivity, and specificity demonstrated the RIA to be reliable. Coefficients for intra- and inter-assay variation were 1.20 and 2.35% for Cortisol and 3.50 and 3.97% for corticosterone, respectively. Sensitivity was 3.3 and 4.9 pg for cortisol and corticosterone, respectively. A distinct diurnal rhythm in plasma cortisol and corticosterone synchronous with photoperiod was found in free-ranging and captive bighorn sheep. A significant difference (P < 0.01) existed between the mean 24-h plasma cortisol concentration for captive (33.04 ± 5.97 ng/mL) and free-ranging (49.20 ± 8.17 ng/mL) bighorn. Corticosterone levels were not significantly distinct between captive and free-ranging bighorn. The mean scotophase cortisol concentration in free-ranging class III rams (60.97 ± 3.21 ng/mL) was significantly greater (P < 0.05) than the mean scotophase cortisol concentration (54.03 ± 5.97 ng/mL) of the free ranging group. Absence of group interactions in solitary rams may be sufficiently stressful so as to entrain increased plasma cortisol concentrations.
Seasonal dynamics of Allopodocotyle boleosomi (Pearse, 1924) n. comb. (Digenea: Opecoelidae) in Wisconsin darters (Etheostomatinae)
Authors: Kuntz Susan M. , Font William F.
Published: December 2009

Allopodocotyle boleosomi n. comb., created for Allocreadium boleosomi Pearse, 1924, is redescribed and its taxonomic history is reviewed. The purpose of our study was to determine seasonal population dynamics of A. boleosomi in O'Neil Creek darters. Etheostoma flabellare was most heavily infected with A. boleosomi. Etheostoma flabellare is one of the six species of darters occurring at a study site in O'Neil Creek, Chippewa County. Wisconsin. Seasonal changes in abundance and maturation of A. boleosomi in E. flabellare were studied for 14 consecutive months, and its occurrence in E. nigrum, E. caeruleum, E. zonale, Percina maculata, and P. caprodes was observed. Specimens of A. boleosomi were present in E. flabellare throughout the year, but displayed a distinct seasonal pattern of prevalence, relative density, and maturation. Most recruitment occurred in May and June and peak occurrence of gravid specimens was reached in July. Little growth or development of A. boleosomi took place during autumn, winter, or early spring. Each of the five other syntopic species of darters was less suitable as a host for A. boleosomi, some because of ecological differences and others perhaps because of physiological factors. Five additional species of helminths occurred in O'Neil Creek darters: Crepidostomum isostomum, Bothriocephalus formosus, Carnallanus oxycephalus, Pomphorhynchus bulbocolli, and Neoechinorhynchus sp.
Parental investment: the problem of currency
Authors: Knapton Richard W.
Published: December 2009

Evolutionary thinking of sexual strategies has been shaped by a stimulating paper by R. L. Trivers on parental investment and sexual selection. However, there is a major problem in the practical application of the concept of parental investment to those systems in which both males and females offer a substantial amount of parental investment in each offspring, but where the investment of each parent takes different forms. Quantifiable measures (i.e., currency) of the investments of each parent can be of different units (in terms of time, energy, and a risk factor) and hence not additive, and thus one cannot predict who will be the choosier sex.
Limb regeneration in newts with spontaneous skin cancer
Authors: Tsonis Panagiotis A.
Published: December 2009

In the present investigation, newts bearing spontaneous papillomas were used to study whether the presence of the tumors (regardless of location) influence regeneration of limbs amputated distal to the elbow. In addition, when the growing papillomas were found in limbs or tails, the amputation was performed through the sites of the tumor to study how these tumor cells behave under the influence of regeneration and whether morphogenesis is affected owing to the presence of a cancer at the amputation site. Limb regeneration was found to be generally retarded in spontaneous papilloma-bearing newts. The regenerating limbs of these animals reached the digit stage much later than tumor-free controls. When the regenerative part was amputated through the tumor, the normal epithelium covered the wound and the papilloma cells divided over it, thus forming a separate cell layer. The tumor cells grew rapidly and replaced the lost part of the tumor, but did not invade the blastema, even though they metastasized along the regenerates. Morphogenesis of the limbs did not appear to be affected.
ELECTRIC CHARGE ESTIMATION OF A NEWBORN BLACK HOLE
Authors: BAUSHEV ANTON , CHARDONNET PASCAL
Published: December 2009

Though a black hole can theoretically possess a very big charge ([Formula: see text]), the charge of the real astrophysical black holes is usually considered to be negligible. This supposition is based on the fact that an astrophysical black hole is always surrounded by some plasma, which is a very good conductor. However, it disregards the fact that black holes usually have some angular momentum, which can be interpreted as their rotation of a sort. If in the plasma surrounding the hole there is some magnetic field, it leads to electric field creation and, consequently, charge separation.

In this article we estimate the upper limit of the electric charge of stellar mass astrophysical black holes. We have considered a new black hole formation process and shown that the charge of a newborn black hole can be significant (~ 1013 C ). Though the obtained charge of an astrophysical black hole is big, the charge-to-mass ratio is small, [Formula: see text], and it is not enough to affect significantly either the gravitational field of the star or the dynamics of its collapse.
OBSERVATIONAL CONSTRAINTS ON THE GENERALIZED CHAPLYGIN GAS
Authors: CAMPO SERGIO DEL , VILLANUEVA J. R.
Published: December 2009

In this paper we study a quintessence cosmological model in which the dark energy component is considered to be the generalized Chaplygin gas and the curvature of the three-geometry is taken into account. Two parameters characterize this sort of fluid: ν and α. We use different astronomical data for restricting these parameters. It is shown that the constraint ν ≲ α agrees well enough with the astronomical observations.
Variscan intra-orogenic extensional tectonics in the Ossa-Morena Zone (Évora-Aracena-Lora del Rı́o metamorphic belt, SW Iberian Massif): SHRIMP zircon U-Th-Pb geochronology
Authors: Pereira M. Francisco , Chichorro Martim , Williams Ian S. , Silva José B. , Fernández Carlos , Dı́az-azpı́roz Manuel , Apraiz Arturo , Castro Antonio
Published: December 2009

Following a Middle–Late Devonian (
c
. 390–360 Ma) phase of crustal shortening and mountain building, continental extension and onset of high-medium-grade metamorphic terrains occurred in the SW Iberian Massif during the Visean (
c
. 345–326 Ma). The Évora–Aracena–Lora del Rı́o metamorphic belt extends along the Ossa–Morena Zone southern margin from south Portugal through the south of Spain, a distance of 250 km. This major structural domain is characterized by local development of high-temperature–low-pressure metamorphism (
c
. 345–335 Ma) that reached high amphibolite to granulite facies. These high-medium-grade metamorphic terrains consist of strongly sheared Ediacaran and Cambrian–early Ordovician (
c
. 600–480 Ma) protoliths. The dominant structure is a widespread steeply-dipping foliation with a gently-plunging stretching lineation generally oriented parallel to the fold axes. Despite of the wrench nature of this collisional orogen, kinematic indicators of left-lateral shearing are locally compatible with an oblique component of extension. These extensional transcurrent movements associated with pervasive mylonitic foliation (
c
. 345–335 Ma) explain the exhumation of scarce occurrences of eclogites (
c
. 370 Ma). Mafic-intermediate plutonic and hypabyssal rocks (
c
. 355–320 Ma), mainly I-type high-K calc-alkaline diorites, tonalites, granodiorites, gabbros and peraluminous biotite granites, are associated with these metamorphic terrains. Volcanic rocks of the same chemical composition and age are preserved in Tournaisian–Visean (
c
. 350–335 Ma) marine basins dominated by detrital sequences with local development of syn-sedimentary gravitational collapse structures. This study, supported by new U–Pb zircon dating, demonstrates the importance of intra-orogenic transtension in the Gondwana margin during the Early Carboniferous when the Rheic ocean between Laurussia and Gondwana closed, forming the Appalachian and Variscan mountains.