bluuebunny/crossref_metadata_2025 huggingface dataset:
The structural organisation of an elastic fibre network in the aorta of the cephalopod Octopus dofleini
Authors: Shadwick Robert E. , Gosline John M.
Published: January 2010

The dorsal aorta of the cephalopod Octopus dofleini is the large blood vessel through which blood flows from the systemic heart. The walls of this artery are composed of thick circular and longitudinal layers of striated muscle cells. Outside the muscle layers is a loose collagenous adventitia. Innermost and adjacent to the lumen is a layer of elastic fibres which have structural similarities to elastin fibres in the arteries of vertebrates. These fibres also extend into the muscle layers of the octopus aorta and appear to form a continuous network of extracellular connective tissue which provides the mechanical basis for long-range elasticity in the artery wall of this cephalopod.
Aerobic and anaerobic contributions to energy metabolism in perfused isolated sea raven (Hemitripterus americanus) hearts
Authors: Driedzic William R. , Scott Donna L. , Farrell Anthony P.
Published: January 2010

The relative contribution of aerobic and anaerobic metabolism to ATP production was assessed in sea raven (Hemitripterus americanus) hearts. The problem was approached by measuring the rates of oxygen consumption and lactate production by perfused isolated hearts performing mechanical work. In the experimental preparation aerobic metabolism could account for essentially all of the ATP synthesized; as such, the organization of metabolism in this fish heart appears similar to reptilian and mammalian hearts under conditions of adequate oxygen availability.
Does cuticular elasticity regulate the size of the blood meal imbibed by female Glossina austeni?
Authors: Carruthers C. B. , Davey K. G.
Published: January 2010

In tsetse flies, a larva grows to maturity inside the uterus of the female. The size of the blood meal imbibed by females is known to increase at ovulation and decrease as the larva gets larger, so that the total volume of the fly remains constant. This has led to the hypothesis that meal size is determined by cuticular elasticity. Direct measurement of the elasticity of abdominal cuticle in mated females, before and after ovulation, and in virgin females, which do not ovulate, demonstrates that cuticular elasticity is unrelated to ovulation. Further, meal size is not closely correlated with cuticular elasticity. The hypothesis is therefore rejected.
A revision of the genus Aptilotus Mik in North America (Diptera, Sphaeroceridae)
Authors: Marshall S. A.
Published: January 2010

The genus Aptilotus Mik is revised to include 10 Nearctic species. Aptilotus spatulatus n. sp., A. cruciatus n. sp., A. nigriscapus n. sp., and A. luteoscapus n. sp. are described as new and a key to the Nearctic species is provided. The genus Carolinaptera Richards is placed in synonomy with Aptilotus and the following new combinations are given: Aptilotus pulex (Richards), A. luctuosus (Spuler), A. concavus (Spuler), A. beckeri (Duda), A. anaptera (Papp and Roháček), A. franzi (Papp and Roháček), A. gomerensis (Papp and Roháček), A. pilifemorata (Papp and Roháček), and Minilimosina dissimilicosta (Spuler).
Physiological and pharmacological investigation of the nonvascularized marine teleost heart with adrenergic and cholinergic agents
Authors: Stuart Robert E. , Hedtke James L. , Weber Lavern J.
Published: January 2010

Teleost hearts can be classified as either vascularized (coronaries) or nonvascularized, based on the arrangement of the ventricular myocardium. Anatomical investigation of the buffalo sculpin (Enophrys bison) heart has revealed that it lacks coronary circulation. To see if Starling's law was applicable in the nonvascularized teleost heart and to characterize the heart as to the type of adrenergic receptors present, isolated sculpin hearts were attached by the sinus venosus to a modified Langendorff perfusion apparatus. A pressure transducer was placed in series between the bulbus arteriosus and a vertical 15-cm length of glass tubing so that the heart was forced to work against a pressure head of 15 cm H2O (1.5 kPa). Heart rate, pressure, and cardiac output were monitored. As atrial perfusion pressure was increased, the sculpin heart responded with a positive inotropy and an increase in cardiac output. Heart rate did not change. Epinephrine caused an increase in heart rate and a lowered stroke volume. Acetylcholine resulted in negative chronotropy and elevated stroke volume. The data indicate that the contractility increases with elevated filling pressure, demonstrating Starling's law. Isoproterenol administration resulted in positive chronotropy which could be blocked by propranolol. Methoxamine was without effect. The buffalo sculpin heart appears to be under the control of beta adrenergic receptors.
Neural pathways mediating salivary fluid secretion in the ixodid tick Amblyomma hebraeum
Authors: Kaufman W. R. , Harris R. A.
Published: January 2010

In ixodid ticks, the salivary glands are innervated by at least two nerves: one arising from the so called lateral plexus (SGNlp) and one arising as a branch of the palpal nerve (SGNpn). The injection of cholinomimetic drugs or large volumes of isosmotic saline into the haemocoel is known to stimulate salivary fluid secretion. The object of this study was to determine which nerves mediate the latter responses. We challenged ticks with either carbachol or isosmotic saline after cutting various nerves bilaterally. Cutting the SGNlp attenuated both carbachol-induced and saline-induced secretion. Cutting the opisthosomal nerves attenuated only saline-induced secretion. Cutting the SGNpn appeared to inhibit salivation in a nonspecific manner. The data indicate that saline-induced salivation is mediated by a sensory receptor located in the opisthosoma, whereas carbachol exerts its effect either in the central nervous system or via a sensory receptor located in the cephalothorax.
Rates of population increase and mortality for sessile ciliates on artificial substrates in a stream riffle
Authors: Taylor William D.
Published: January 2010

Ciliophorans are capable of very high fission rates, but it is not known whether these rates are typical of field populations. This study measures rates of colony size and population increase, along with colony and individual survival times, for sessile species inhabiting artificial substrates placed in a stream riffle. This was accomplished by bringing the substrates into the laboratory for a short period each day and counting and recording the positions of individuals and colonies. Abundant species on the artificial substrates included Metacineta mystacina, Opercularia coarctata, and Epistylis plicatilis. Artificial substrates were colonized by these sessile ciliates within a week of being placed in the stream. After colonization, there was usually a period of exponential population growth, eventually followed by a levelling off or decline. Slow or negative population growth was associated with high mortality. Population doubling times and mean individual lifespan fall in the range of 5 to 24 h, indicating that these field populations displayed near-maximal fission rates.
Production of the amphipod Hyalella azteca (Saussure) in a northern Ontario lake
Authors: Lindeman Dorothy H. , Momot Walter T.
Published: January 2010

Annual production of the amphipod, Hyalella azteca, was estimated in three habitats of the upper littoral zone of Dock Lake, Ontario, over a 2-year period (1980–1981). Cohort production (P) by the size frequency method was 1.39 g/m2 (dry weight), mean annual biomass (B) was 0.36 g/m2, and the P/B ratio was 3.9 for the 1980 year class. Five other methods for estimating production were applied to this cohort, providing comparable estimates ranging from 1.21 (instantaneous growth) to 1.65 (cohort G) g/m2. Size frequency estimates of annual production for 1980 and 1981 were 1.24 and 1.40 g/m2, respectively. The annual P/[Formula: see text] ratios of 3.9 and 4.0 for these 2 years agree with the cohort value. A comparison of production estimates for Hyalella azteca in the literature shows a gradient of production which correlates with the habitat temperature regime.
A comparison of the biological characteristics of Trichinella spiralis var. pseudospiralis between mice and bird hosts
Authors: Bober Christiane M. , Dick T. A.
Published: January 2010

Biological characteristics and phenotypic variations of Trichinella spiralis var. pseudospiralis were determined from Crl: COBS CFW (Swiss Webster) mice, Coturnix coturnix japonica, Larus argentatus, L. delawarensis, and L. pipixcan. Trichinella spiralis var. pseudospiralis was located in the anterior part of the intestine of all hosts, but when surgically transplanted in mice the parasite did equally well in all sections of the small intestine. Differences in biological characteristics of T. s. var. pseudospiralis were noted between mouse and bird hosts and appear to be related to the more variable genome of the bird hosts, the nature of the digestive tract, and the intensity and timing of the host immune response. Larvae of T. s. var. pseudospiralis were concentrated in the muscles of legs, breasts, and thoracic and abdominal cavities. It was concluded that T. s. var. pseudospiralis may be a relatively recent parasite of birds that has limited chance for success.
Skrjabingylus Petrov, 1927 (Nematoda: Metastrongyloidea) emended with redescriptions of S. nasicola (Leuckart, 1842) and S. chitwoodorum Hill, 1939 from North American mustelids
Authors: Lankester Murray W.
Published: January 2010

Skrjabingylus Petrov, 1927 is emended. Skrjabingylus nasicola (Leuckart, 1842) in Mustela spp. and S. chitwoodorum Hill, 1939 of skunk are redescribed and distinguished from S. lutrae Lankester and Crichton, 1972, the only other species of the genus known to occur in North America. Each of the three species is identified by body size, length of the male spicules, the distinctive morphology of the distal tip of the spicules and the host in which they occur. Skrjabingylus magnus Webster, 1965 is considered a synonym of S. chitwoodorum. First- and second-stage larvae of S. nasicola and S. chitwoodorum are similar in appearance but the third-stage larvae can be distinguished from each other and from those of S. lutrae by the morphology of the cuticularized buccal capsule. The sex of third-stage S. chitwoodorum larvae can be determined by the length of the genital primordium. No sex differences were visible in third-stage larvae of S. nasicola.
Major range extensions of anadromous salmonids and first record of chinook salmon in the Mackenzie River drainage
Authors: McLeod C. L. , O'Neil J. P.
Published: January 2010

Spawning migrations of chum salmon, Oncorhynchus keta (Walbaum), and Arctic cisco Coregonus autumnalis (Pallas), in the Liard River system (Mackenzie River drainage) within the Northwest Territories and British Columbia were documented during the period 1978 to 1981. These species have not been reported previously from the Liard River. The points of capture, as far upstream as the Grand Canyon of the Liard, represent a major southerly range extension in the Mackenzie River drainage and upstream migrations of nearly 2000 km from the Beaufort Sea. The first record of a chinook salmon, Oncorhynchus tshawytscha (Walbaum), from the Mackenzie River drainage is reported also. The specimen was collected in the Liard River, Northwest Territories, and was probably a stray, accompanying a spawning escapement of chum salmon.
Effect of nonessential amino acids on phagostimulation and maintenance of the pea aphid, Acyrthosiphon pisum
Authors: Srivastava P. N. , Auclair J. L. , Srivastava U.
Published: January 2010

Eleven nonessential amino acids and amides, at concentrations ranging from 0.001 to 1.0% in 35% sucrose solutions, were individually tested for their role in phagostimulation, growth, and survival in Acyrthosiphon pisum (Harris). Alanine and -γ-amino butyric acid were generally phagostimulatory, whereas asparagine, aspartic acid, cysteine, cystine, glutamic acid, glycine, proline, serine, and tyrosine were generally inhibitory. Asparagine, glutamic acid, glycine, and proline supported growth and prolonged survival; aspartic acid and tyrosine increased weight but did not prolong survival, and alanine, -γ-amino butyric acid, cystine, cysteine, and serine neither promoted growth nor prolonged survival.
Mink and otter as indicators of mercury in Manitoba waters
Authors: Kucera Emil
Published: January 2010

Tissues of mink (Mustela vison) and river otter (Lutra canadensis) from several Manitoba drainage basins were analyzed for total mercury. Results were compared among drainage basins and with published data. With some variations, mercury concentrations followed similar patterns in both species. Levels were highest in the samples from Winnipeg River and Burntwood River; these were significantly (p < 0.05) higher than in samples from Duck Mountain that were comparable to background levels reported in the literature. Mean concentrations of mercury in samples from all areas were well below the reported acutely toxic levels. Mink and otter accumulated about 10 times more mercury than did predatory fishes from the same drinage areas. Monitoring of environmental mercury levels through mink and otter is a viable method, and these furbearers can serve as sensitive indicators of mercury even at very low levels of environmental contamination.
The effects of interspecific competition on Diaptomus leptopus in a montane lake: an experimental field study
Authors: Olenick Roberta Jill
Published: January 2010

Despite high densities in an upstream lake, the calanoid copepod Diaptomus leptopus is extremely scarce in oligotrophic montane Eunice Lake, British Columbia. Field experiments tested the hypothesis that competition from zooplankton resident in Eunice Lake prevents immigrant D. leptopus from colonizing.Experiments in 1979 exposed a standard density of D. leptopus to all Eunice Lake zooplankton species at lake densities (control) and at reduced densities (low density), and to all Eunice Lake species except one of Daphnia rosea (Daphnia removal), Diaptomus kenai (kenai removal), or Diaptomus tyrrelli (tyrrelli removal). Improved D. leptopus performance in noncontrol treatments was evidence for competition in controls. Performance measures included density, survival, and reproduction. Similar and poor performances of D. leptopus in control, Daphnia-removal, and kenai-removal treatments plus high concentrations of D. leptopus nauplii in the tyrrelli-removal treatment suggested that only D. tyrrelli competed with D. leptopus. However, similarity between tyrrelli-removal and low-density treatments in D. leptopus naupliar concentrations confounded competition from D. tyrrelli with diffuse competition from several Eunice Lake species combined. Experiments in 1980, designed to separate these effects, provided no evidence of interspecific interactions. Cool 1980 temperatures presumably reduced competition for algal foods by lowering zooplankton respiration rates.
Substrate preferences of mitochondria isolated from locust (Locusta migratoria) and blowfly (Phormia regina) fat bodies
Authors: Ballantyne J. S. , Storey K. B.
Published: January 2010

The preferred substrate of the fat body mitochondria of both the locust (Locusta migratoria) and the blowfly (Phormia regina) based on state three rates of oxidation is palmitoyl-L-carnitine. The fat body mitochondria of the locust do not oxidize proline plus pyruvate, pyruvate plus malate, or α-glycerophosphate under the conditions used. The mitochondria of the blowfly fat body do oxidize these substrates at high rates. The mitochondria isolated from the locust fat body do not oxidize fumarate or oxaloacetate at measurable rates. The mitochondria isolated from the blowfly fat body do not oxidize citrate, isocitrate, or fumarate at measurable rates.
Studies on gametogenesis in Tachygonetria vivipara Wedl, 1862 and Thelandros alatus Wedl, 1862 (Oxyuroidea; Nematoda) from Uromastix acanthinurus in Morocco
Authors: Adamson Martin L. , Petter Annie J.
Published: January 2010

Chromosome changes during gametogenesis in Thelandros alatus and Tachygonetria vivipara, pharyngodonids (Oxyuroidea; Nematoda) from Uromastix acanthinurus from Morocco, indicate that both species are haplodiploid. Meiosis was normal in females of Thelandros alatus. There were five bivalents, indicating a diploid number of 10 chromosomes. Most embryos in utero contained 5 chromosomes but one was observed with 10. Spermatogonial divisions contained five chromosomes; there was no evidence of chromosome pairing nor bivalent formation in males and divisions in the transformation zone of the testis contained five chromosomes with fuzzy outlines. There was no evidence of chromosome pairing nor bivalent formation in males of Tachygonetria vivipara. Oviparous and ovoviviparous females were examined. Three bivalents formed indicating a diploid number of six chromosomes. Chromosomes were counted in 179 embryos from 79 oviparous females; 128 were diploid (i.e., female) and 51 were haploid (i.e., male). It is suggested that the life cycle of T. vivipara resembles that of Gyrinicola batrachiensis: hosts are colonized by thick-shelled eggs, most of which develop into ovoviviparous females, and these females, if not fecundated, produce males parthenogenetically which develop in the same host. After being fecundated (sometimes by way of mother-son matings) the same females produce oviparous female progeny which develop in the same host. Eggs from oviparous females colonize a new host.
Scent marking by cheek rubbing in the northern flying squirrel (Glaucomys sabrinus)
Authors: Ferron Jean
Published: January 2010

Scent marking is relatively well documented in ground squirrels. Some work has been conducted on arboreal sciurids, but no detailed study on scent marking has yet been published on flying squirrels, a distinct subfamily of the Sciuridae. The objective of the present study is to fill this gap by analysing scent-marking behaviour by cheek rubbing in the Northern flying squirrel, Glaucomys sabrinus. The presence and importance of oral glands are demonstrated histologically, and a detailed ethological study of 78 cases of scent marking is presented. A contextual analysis, as defined by Drummond, and a comparison with other sciurids are carried out in order to understand the role played by scent marking in this semisocial species. It appears that scent marking by cheek rubbing is used by G. sabrinus to maintain the animal's familiarity with its home range by "reassuring" and orienting it in that environment. In addition, scent marking by cheek rubbing may also function in intraspecific communication, notably with regard to sharing or avoidance of the same grooming, resting, and feeding sites.
The growth of Thick-billed Murre chicks at colonies in Hudson Strait: inter- and intra-colony variation
Authors: Gaston A. J. , Chapdelaine G. , Noble D. G.
Published: January 2010

Comparison of growth rates and fledging weights recorded for Thick-billed Murre chicks (Uria lomvia) by previous investigators shows that these parameters vary widely between studies. We measured growth rates and fledging weights at four colonies in the Hudson Strait area to examine the magnitude of variation both within and among colonies. Significant variations among years and among different areas of a single colony were detected but found to be less important than colony-specific factors in determining overall variation. A negative correlation between colony size and chick fledging weights suggests that colony size may be an important determinant of intercolony differences.
Choix d'une méthode d'estimation de densité de population de la marmotte commune (Marmota monax)
Authors: Nuckle Jacques R. , Bergeron Jean-Marie
Published: January 2010

Intensive trapping of 433 groundhogs (Marmota monax) between 1977 and 1980 led to the comparison of different methods designed to evaluate population density. Parametric (truncated Poisson distribution, geometric, linear regression) and nonparametric (Petersen, Schumacher–Eschmeyer, Schnabel–Overton, Overton) methods were tested; of these, only the Overton method and the method designed by Schnabel and modified by Overton gave results in accordance with the actual occupation of the groundhog dens. As a general rule, parametric methods tend to overestimate density whereas nonparametric methods give results that are closer to the observations and measures recorded in the field.
Spring migratory synchrony of salmonid, catostomid, and cyprinid fishes in Rivière à la Truite, Québec
Authors: Montgomery W. Linn , McCormick Stephen D. , Naiman Robert J. , Whoriskey Jr. Frederick G. , Black Geoff A.
Published: January 2010

During May–June 1980 and June–July 1982, six fish species exited Rivière à la Truite, a major tributary of the lower Moisie River, Quebec, in highly synchronized emigrations. Species included longnose sucker (Catostomus catostomus), white sucker (C. commersoni), lake chub (Couesius plumbeus), juvenile sea lamprey (Petromyzon marinus), Atlantic salmon (Salmo salar) parr and smolt, and anadromous brook trout (Salvelinus fontinalis). In 1980, emigration for all species except the lamprey began on 27 May and ended by 9–11 June; lamprey movements began on 4–5 June and peaked on 10 June. Similar but slightly later patterns occurred in 1982. Onset of the runs in each year coincided with declining water levels and discharge. Thus species of widely different habits exhibit similar and highly synchronized migratory patterns, possibly in response to strong changes in stream environment.
Bats of Kootenay, Glacier, and Mount Revelstoke national parks in Canada: identification by echolocation calls, distribution, and biology
Authors: Fenton M. B. , Merriam H. G. , Holroyd G. L.
Published: January 2010

We studied the behaviour, echolocation calls, and distribution of bats in Kootenay, Glacier, and Mount Revelstoke national parks in British Columbia, Canada. Presented here are keys for identification of nine species of bats by their echolocation calls as rendered by two different bat-detecting systems. The species involved include Myotis lucifugus, M. evotis, M. volans, M. septentrionalis, M. californicus, Lasionycteris noctivagans, Eptesicus fuscus, Lasiurus cinereus, and L. borealis. The distribution of these species within the three parks was assessed by capturing bats in traps and mist nets and by monitoring of their echolocation calls. Most of the species exploited concentrations of insects around spotlights, providing convenient foci of activity for assessing distribution. Although most species of Myotis were commonly encountered away from the lights, Lasiurus cinereus in Kootenay National Park was only regularly encountered feeding on insects at lights. This species was not detected in Glacier National Park, and although we regularly encountered it in the town of Revelstoke, it was rarely encountered in Mount Revelstoke National Park. Another focus of bat activity was small pools in cedar forest in Mount Revelstoke National Park. This involved high levels of Myotis spp. activity at dusk as the bats came to the pools to drink.
Ultrastructural changes in posterior midgut cells associated with blood feeding in adult female Rhodnius prolixus Stal (Hemiptera: Reduviidae)
Authors: Billingsley P. F. , Downe A. E. R.
Published: January 2010

Modifications of posterior midgut cells of Rhodnius prolixus following a meal of rabbit blood are described. Prominent stacks and whorls of rough endoplasmic reticulum become redistributed following a blood meal but later reform during the postfeeding period. Lysosomes undergo internal structural changes and apparent fluctuations in their number per cell as a result of blood meal ingestion. Before blood feeding, the apical surface of the midgut cells show a typical arrangement of a plasma membrane covered on the lumenal surface by a glycocalyx. After a blood meal, a more complex organisation appears, consisting of two plasma membranes separated by an electron-dense matrix. The lumenal apical membrane proliferates during the digestion period to form loosely organised extracellular membrane layers which may function as a peritrophic membrane. Changes in the rough endoplasmic reticulum and lysosomes and modifications to the apical cell surface appear to coincide with previously described proteinase activity cycles in the posterior midgut of R. prolixus. The implications of these results are discussed and are compared with similar ultrastructural events from haematophagous Diptera.
The contractile vacuole of Amoeba proteus. Some of the consequences of the microcoalescence hypothesis
Authors: Couillard Pierre , Bourdeau Marc
Published: January 2010

A simple model describing the contractile vacuole cycle in the freshwater protozoan Amoeba proteus is used to compute coalescence frequencies of submicroscopic vesicles needed to account for the growth of the vacuole. With this model, microvesicles were first considered as the source of volume and then as contributing the surface for the growing vacuole. Results show that vacuole growth by microvesicle accretion entails excessive fusion frequencies, thus generating a huge surplus of membrane. It is thus unlikely that microvesicle accretion is the only process involved in the growth of the contractile vacuole. On the other hand, vacuolar surface growth through vesicle accretion is much more plausible. The consequences of these facts are discussed.
Organ-specific metabolism during anoxia and recovery from anoxia in the cherrystone clam, Mercenaria mercenaria
Authors: Korycan Sandra A. , Storey Kenneth B.
Published: January 2010

The levels of intermediary metabolites and end products were quantified in the tissues of the cherrystone clam, Mercenaria mercenaria, over a time course of 96 h of anoxia followed by 48 h of aerobic recovery. Succinate and alanine accumulated as anaerobic products while glycogen and aspartate were utilized as substrates. Succinate accumulation ranged from 12–14 μmol/g wet weight in muscle (phasic and catch adductor, foot) to 25 μmol/g in gill and mantle with 32 μmol/mL released into the mantle cavity fluid. Lesser amounts of alanine were produced, the ratio succinate:alanine varying from 1.4:1 in phasic adductor to 3.2:1 in mantle at 96 h. Aspartate reserves apparently supply the carbon for succinate synthesis over the first 6–12 h of anoxia; subsequent succinate and alanine production probably results from glycogen fermentation. The imino acids alanopine and strombine were not produced in appreciable amounts (<1 μmol/g) during anoxia. When returned to aerated seawater, control levels of alanine and aspartate were reestablished within 24 h; accumulated succinate was catabolized within 48 h. Glycogen content of all tissues showed a sharp decline after 6 h of recovery, perhaps due to enhanced energy demands, but levels increased later in recovery. Tissue ATP levels, which were depressed during anoxia, were restored by 24 h.
Anaerobiosis, recovery from anoxia, and the role of strombine and alanopine in the oyster Crassostrea virginica
Authors: Eberlee John C. , Storey Janet M. , Storey Kenneth B.
Published: January 2010

Tissue-specific metabolism was monitored in gill, mantle, and adductor muscle of the oyster Crassostrea virginica over a time course of 96 h of anoxia followed by 48 h of recovery from anoxia. Succinate and alanine accumulated as products of anaerobic metabolism while aspartic acid was utilized as a substrate of anaerobiosis. The imino acids alanopine and strombine were not produced during anoxia. During aerobic recovery tissue levels of metabolites returned to control levels, succinate within 2 h in mantle and gill and 6 h in muscle, while restoration of alanine levels required about 24 h. Aspartate pools were restored in 4 to 6 h. Alanopine and strombine accumulated during the recovery period. By 2 h of recovery, alanopine content of mantle and gill had risen by 1.3 and 0.5 μmol/g, respectively, while in adductor muscle both alanopine and strombine accumulated with net increases of 2 and 2.7 μmol/g. Imino acid content declined after 6–12 h of recovery returning to control levels by 24 h. The roles of alanopine and strombine in the oyster are not as products of anaerobic metabolism but rather as products of glycolytic function during recovery. The increased metabolic rate associated with the return to aquatic conditions appears to require some glycolytic energy production to meet overall tissue energy requirements of recovery.
Species specificity of giant nerve fiber conduction velocity in oligochaetes
Authors: Drewes C. D. , Callahan C. A. , Fender W. M.
Published: January 2010

Giant nerve fiber conduction velocities were studied using noninvasive electrophysiological recording techniques in adults from 12 species of oligochaetes, representing five different families. Two separate and stereotyped all-or-none response patterns to tactile stimulation (corresponding to medial and lateral giant fiber spike responses) were observed in all 12 species, suggesting that this functional dichotomy has been a conserved feature in the evolution of oligochaete escape reflexes. The results indicate that there is considerable species specificity with respect to medial and lateral giant fiber conduction velocities, which may derive from species differences in genetically determined limits in the radial growth of the giant fibers.
Age-related allozymic variation in the cyprinid fish Alburnus alburnus
Authors: Handford Paul
Published: January 2010

A polymorphism in water-soluble muscle esterases in the freshwater cyprinid fish Alburnus alburnus, the bleak, is described. The variation may be attributed to three codominant alleles at a single locus. Strong distortions from Hardy–Weinberg expectation are noted in samples from all length groups of fish at all times of the year. All homozygotes and one heterozygote are generally in deficit, while the two common heterozygotes are present in excess. Analysis of the genotype frequencies on a basis of random mating indicates that the polymorphism is stable and close to equilibrium. There are significant associations between size class and the frequencies of alleles 1 and 2 and genotype 33.
A preliminary survey of known and potentially Canadian and Alaskan centipedes (Chilopoda)
Authors: Kevan D. Keith McE.
Published: January 2010

The centipedes of Canada and Alaska are poorly known. This paper indicates the present state of knowledge of the class, including "economic" and "biological" aspects, insofar as this is relevant to Canada and the adjacent United States of America. The systematic and other related literature applicable to the region is briefly reviewed. The principal part of the paper provides a classified list of the species of centipedes (with most of their synonyms) hitherto known for Canada and Alaska. In order to alert workers as to possible future additions to the Canadian fauna, those species known from other adjacent United States, southern New England, and Oregon are added. The known distribution of each species is given by province, territory, or state within the region, but known distributions further afield are not generally indicated. About 70 species (over a dozen of them introduced) are known for Canada and Alaska. Some 70 or so are found in the adjacent United States or southern New England. It is estimated that the Canadian–Alaskan fauna may eventually prove to comprise more than 100 species of Chilopoda. A note on Canadian Symphyla (including the record of a member of a hitherto unreported family) is appended.
ON STRUCTURAL AND GRAPH THEORETIC PROPERTIES OF HIGHER ORDER DELAUNAY GRAPHS
Authors: ABELLANAS MANUEL , BOSE PROSENJIT , GARCÍA JESÚS , HURTADO FERRAN , NICOLÁS CARLOS M. , RAMOS PEDRO
Published: January 2010

Given a set P of n points in the plane, the order-k Delaunay graph is a graph with vertex set P and an edge exists between two points p, q ∈ P when there is a circle through p and q with at most k other points of P in its interior. We provide upper and lower bounds on the number of edges in an order-k Delaunay graph. We study the combinatorial structure of the set of triangulations that can be constructed with edges of this graph. Furthermore, we show that the order-k Delaunay graph is connected under the flip operation when k ≤ 1 but not necessarily connected for other values of k. If P is in convex position then the order-k Delaunay graph is connected for all k ≥ 0. We show that the order-k Gabriel graph, a subgraph of the order-k Delaunay graph, is Hamiltonian for k ≥ 15. Finally, the order-k Delaunay graph can be used to efficiently solve a coloring problem with applications to frequency assignments in cellular networks.
Turbulent Plumes in Nature
Authors: Woods Andrew W.
Published: January 2010

This review describes a range of natural processes leading to the formation of turbulent buoyant plumes, largely relating to volcanic processes, in which there are localized, intense releases of energy. Phenomena include volcanic eruption columns, bubble plumes in lakes, hydrothermal plumes, and plumes beneath the ice in polar oceans. We assess how the dynamics is affected by heat transfer, particle fallout and recycling, and Earth's rotation, as well as explore some of the mixing of the ambient fluid produced by plumes in a confined geometry.
Measurement of the Velocity Gradient Tensor in Turbulent Flows
Authors: Wallace James M. , Vukoslavčević Petar V.
Published: January 2010

This article reviews the principal experimental methods currently available to simultaneously measure all the terms of the velocity gradient tensor of turbulent flows. These methods have been available only for a little more than 20 years. They have provided access to the most fundamental and defining properties of turbulence. The methods include small, multisensor, hot-wire probes that provide single-location, time-resolved measurements of the tensor and various optical arrangements, most of which provide the tensor information over a larger spatial extent but, in most cases, without resolution in time. Data-reduction algorithms, spatial-resolution issues, and the use of Taylor's hypothesis are addressed in evaluating the accuracy of the various methods.
Fluvial Sedimentary Patterns
Authors: Seminara G.
Published: January 2010

Geomorphology is concerned with the shaping of Earth's surface. A major contributing mechanism is the interaction of natural fluids with the erodible surface of Earth, which is ultimately responsible for the variety of sedimentary patterns observed in rivers, estuaries, coasts, deserts, and the deep submarine environment. This review focuses on fluvial patterns, both free and forced. Free patterns arise spontaneously from instabilities of the liquid-solid interface in the form of interfacial waves affecting either bed elevation or channel alignment: Their peculiar feature is that they express instabilities of the boundary itself rather than flow instabilities capable of destabilizing the boundary. Forced patterns arise from external hydrologic forcing affecting the boundary conditions of the system. After reviewing the formulation of the problem of morphodynamics, which turns out to have the nature of a free boundary problem, I discuss systematically the hierarchy of patterns observed in river basins at different scales.
Influence of cell background on pharmacological rescue of mutant CFTR
Authors: Pedemonte Nicoletta , Tomati Valeria , Sondo Elvira , Galietta Luis J. V.
Published: January 2010

Cystic fibrosis (CF) is caused by mutations in the CFTR chloride channel. Deletion of phenylalanine 508 (F508del), the most frequent CF mutation, impairs the maturation and gating of the CFTR protein. Such defects may be corrected in vitro by pharmacological modulators named as correctors and potentiators, respectively. We have evaluated a panel of correctors and potentiators derived from various sources to assess potency, efficacy, and mechanism of action. For this purpose, we have used functional and biochemical assays on two different cell expression systems, Fischer rat thyroid (FRT) and A549 cells. The order of potency and efficacy of potentiators was similar in the two cell types considered, with phenylglycine PG-01 and isoxazole UCCF-152 being the most potent and least potent, respectively. Most potentiators were also effective on two mutations, G551D and G1349D, that cause a purely gating defect. In contrast, corrector effect was strongly affected by cell background, with the extreme case of many compounds working in one cell type only. Our findings are in favor of a direct action of potentiators on CFTR, possibly at a common binding site. In contrast, most correctors seem to work indirectly with various mechanisms of action. Combinations of correctors acting at different levels may lead to additive F508del-CFTR rescue.
Prokineticin 2 modulates the excitability of area postrema neurons in vitro in the rat
Authors: Ingves Matthew V. , Ferguson Alastair V.
Published: January 2010

Despite recent evidence describing prokineticin 2 (PK2)-producing neurons and receptors in the dorsomedial medulla, little is known regarding the potential mechanisms by which this circadian neuropeptide acts in the medulla to influence autonomic function. Using whole cell electrophysiology, we have investigated a potential role for PK2 in the regulation of excitability in neurons of the area postrema (AP), a medullary structure known to influence autonomic processes in the central nervous system. In current-clamp recordings, focal application of 1 μM PK2 reversibly influenced the excitability of the majority of dissociated AP cells tested, producing depolarizations (38%) and hyperpolarizations (28%) in a concentration-dependent manner. Slow voltage ramps and ion-substitution experiments revealed that a PK2-induced Cl− current was responsible for membrane depolarization, whereas hyperpolarizations were the result of inhibition of a nonselective cation current. In contrast to these differential effects on membrane potential, nearly all neurons that displayed spontaneous activity responded to PK2 with a decrease in spike frequency. These observations are in accordance with voltage-clamp experiments showing that PK2 caused a leftward shift in Na+ channel activation and inactivation gating. Lastly, using post hoc single-cell RT-PCR technology, we have shown that 7 of 10 enkephalin-expressing AP neurons were depolarized by PK2 indicating that PK2 may have specific inhibitory actions on this population of neurons in the AP to reduce their sensitivity to homeostatic signals. These data suggest that the level of AP neuronal excitability may be regulated by PK2, ultimately affecting AP autonomic control.
Interleukin-10 reduces inflammation, endothelial dysfunction, and blood pressure in hypertensive pregnant rats
Authors: Tinsley John H. , South Sanique , Chiasson Valorie L. , Mitchell Brett M.
Published: January 2010

Hypertensive disorders of pregnancy are characterized by systemic and placental inflammation; however, treatment for these conditions has remained elusive. We tested whether administration of the anti-inflammatory cytokine interleukin-10 (IL-10) during pregnancy would attenuate the hypertension, endothelial dysfunction, proteinuria, and inflammation seen in pregnant DOCA/saline-treated (PDS) rats. Normal pregnant (NP) rats and PDS were given daily intraperitoneal injections of recombinant IL-10 from gestational day 13 until death on day 20. Systolic blood pressure, aortic endothelium-dependent relaxation responses, and urinary protein excretion were measured on days 13 and 20 of gestation. Fetal number and development, plasma endothelin-1 levels, serum and placental levels of IFNγ and IL-10, and aortic and placental levels of platelet endothelial cell adhesion molecule (PECAM) were assessed on gestational day 20. Systolic blood pressure, aortic endothelial dysfunction, and urinary protein excretion were significantly increased at gestational day 13 in PDS rats. However, all of these were restored to NP levels following IL-10 treatment in PDS rats. IL-10 treatment also significantly increased the number of pups per litter in PDS rats and did not further affect fetal development. The beneficial effects of IL-10 in PDS rats were likely mediated by the decreased plasma levels of endothelin-1, decreased levels of circulating and placental IFNγ, as well as decreased aortic and placental expression of PECAM. These data demonstrate that exogenous IL-10 can normalize blood pressure and endothelial function in pregnancy-induced hypertensive rats and may be beneficial in women with hypertensive disorders of pregnancy.
PKC-α mediates flow-stimulated superoxide production in thick ascending limbs
Authors: Hong Nancy J. , Silva Guillermo B. , Garvin Jeffrey L.
Published: January 2010

We showed that luminal flow increases net superoxide (O2−) production via NADPH oxidase in thick ascending limbs. Protein kinase C (PKC) activates NADPH oxidase activity in phagocytes, cardiomyocytes, aortic endothelial cells, vascular smooth muscle cells, and renal mesangial cells. However, the flow-activated pathway that induces NADPH oxidase activity in thick ascending limbs is unclear. We hypothesized that PKC mediates flow-stimulated net O2−production by thick ascending limbs. Initiation of flow (20 nl/min) increased net O2−production from 4 ± 1 to 61 ± 12 AU/s ( P < 0.007; n = 5). The NADPH oxidase inhibitor apocynin completely blocked the flow-induced increase in net O2−production (2 ± 1 vs. 1 ± 1 AU/s; P > 0.05; n = 5). Flow-stimulated O2−was also blocked in p47phox-deficient mice. We measured flow-stimulated PKC activity with a fluorescence resonance energy transfer (FRET)-based membrane-targeted PKC activity reporter and found that the FRET ratio increased from 0.87 ± 0.02 to 0.96 ± 0.04 AU ( P < 0.05; n = 6). In the absence of flow, the PKC activator phorbol 12-myristate 13-acetate (200 nM) enhanced net O2−production from 5 ± 2 to 92 ± 6 AU/s ( P < 0.001; n = 6). The PKC-α- and βI-selective inhibitor Gö 6976 (100 nM) decreased flow-stimulated net O2−production from 54 ± 15 to 2 ± 1 AU/s ( P < 0.04; n = 5). Flow-induced net O2−production was inhibited in thick ascending limbs transduced with dominant-negative (dn)PKC-α but not dnPKCβI or LacZ (Δ = 11 ± 3 AU/s for dnPKCα, 55 ± 7 AU/s for dnPKCβI, and 63 ± 7 AU/s for LacZ; P < 0.001; n = 6). We concluded that flow stimulates net O2−production in thick ascending limbs via PKC-α-mediated activation of NADPH oxidase.
p66SHC-mediated mitochondrial dysfunction in renal proximal tubule cells during oxidative injury
Authors: Arany Istvan , Faisal Amir , Clark Jeb S. , Vera Trinity , Baliga Radhakrishna , Nagamine Yoshikuni
Published: January 2010

Mitochondrial dysfunction is involved in pathopysiology of ischemia-reperfusion-induced acute kidney injury (AKI). The p66shc adaptor protein is a newly recognized mediator of mitochondrial dysfunction, which might play a role in AKI-induced renal tubular injury. Oxidative stress-mediated Serine36 phosphorylation of p66shc facilitates its transportation to the mitochondria where it oxidizes cytochrome c and generates excessive amount of reactive oxygen species (ROS). The consequence is mitochondrial depolarization and injury. Earlier we determined that p66shc plays an essential role in injury of cultured mouse renal proximal tubule cells during oxidative stress. Here, we studied the role of p66shc in ROS generation and consequent mitochondrial dysfunction during oxidative injury in renal proximal tubule cells. We employed p66shc knockdown renal proximal tubule cells and cells that overexpress wild-type, Serine phosphorylation (S36A), or cytochrome c-binding (W134F) mutants of p66shc. Inhibition of the mitochondrial electron transport chain or the mitochondrial permeability transition revealed that hydrogen peroxide-induced injury is mitochondrial ROS and consequent mitochondrial depolarization dependent. We also found that through Ser36 phosphorylation and mitochondria/cytochrome c binding, p66shc mediates those effects. We propose a similar mechanism in vivo as we demonstrated mitochondrial binding of p66shc as well as its association with cytochrome c in the postischemic kidneys of mice. Thus, manipulating p66shc might offer a new therapeutic modality to ameliorate renal ischemic injury.
Accuracy of Self-Reported Reason for Colorectal Cancer Testing
Authors: Eberth Jan M. , Vernon Sally W. , White Arica , Abotchie Peter N. , Coan Sharon P.
Published: January 2010

Assessment of accuracy of self-reported reason for colorectal cancer testing has been limited. We examined the accuracy and correlates of self-reported reason (screening or diagnosis) for having a sigmoidoscopy or colonoscopy. Patients who had received at least one sigmoidoscopy or colonoscopy within the past 5 years were recruited from a large multispecialty clinic in Houston, TX, between 2005 and 2007. We calculated concordance, positive predictive value, negative predictive value, sensitivity, and specificity between self-reported reason and the medical record (gold standard). Logistic regression was performed to identify correlates of accurate self-report. Self-reported reason for testing was more accurate when the sigmoidoscopy or colonoscopy was done for screening, rather than diagnosis. In the multivariable analysis for sigmoidoscopy, age was positively associated with accurately reporting reason for testing, whereas having two or more colorectal cancer tests during the study period (compared with only one test) was negatively associated with accuracy. In the multivariable analysis, none of the correlates was statistically associated with colonoscopy although a similar pattern was observed for number of tests. Determining the best way to identify those who have been tested for diagnosis, rather than screening, is an important next step. Cancer Epidemiol Biomarkers Prev; 19(1); 196–200
Effects of Supplemental Vitamin D and Calcium on Oxidative DNA Damage Marker in Normal Colorectal Mucosa: A Randomized Clinical Trial
Authors: Fedirko Veronika , Bostick Roberd M. , Long Qi , Flanders W. Dana , McCullough Marjorie L. , Sidelnikov Eduard , Daniel Carrie R. , Rutherford Robin E. , Shaukat Aasma
Published: January 2010

The exact antineoplastic effects of calcium and vitamin D3 in the human colon are unclear. Animal and in vitro studies show that these two agents reduce oxidative stress; however, these findings have never been investigated in humans. To address this, we conducted a pilot, randomized, double-blind, placebo-controlled, 2 × 2 factorial clinical trial to test the effects of calcium and vitamin D3 on a marker of oxidative DNA damage, 8-hydroxy-2′-deoxyguanosine (8-OH-dG), in the normal colorectal mucosa. Patients (N = 92) with at least one pathology-confirmed colorectal adenoma were treated with 2 g/d calcium and/or 800 IU/d vitamin D3 versus placebo over 6 months. Overall labeling and colorectal crypt distribution of 8-OH-dG in biopsies of normal-appearing rectal mucosa were detected by standardized automated immunohistochemistry and quantified by image analysis. After 6 months of treatment, 8-OH-dG labeling along the full lengths of colorectal crypts decreased by 22% (P = 0.15) and 25% (P = 0.10) in the calcium and vitamin D3 groups, respectively, but not in the calcium plus vitamin D3 group. The estimated treatment effects were strongest among participants with higher baseline colon crypt vitamin D receptor expression (P = 0.05). Overall, these preliminary results indicate that calcium and vitamin D3 may decrease oxidative DNA damage in the normal human colorectal mucosa, support the hypothesis that 8-OH-dG labeling in colorectal crypts is a treatable oxidative DNA damage biomarker of risk for colorectal neoplasms, and provide support for further investigation of calcium and vitamin D3 as chemopreventive agents against colorectal neoplasms. Cancer Epidemiol Biomarkers Prev; 19(1); 280–91