bluuebunny/crossref_metadata_2025 huggingface dataset:
ON THE MORPHOLOGY, PHYLOGENY, AND TAXONOMY OF THE LICHEN GENUS STEREOCAULON
Authors: Lamb I. Mackenzie
Published: August 2008

Comparative morphological and anatomical studies on the fruticose lichen genus Stereocaulon show that the pseudopodetial structures originate in two distinct ways, according to which it is proposed to divide the genus into two new subgenera, Holostelidium and Enteropodium. These subgenera are further divided, on a phylogenetic basis, into sections and subsections, some of which are adaptations of previously existing groupings. A phytogeographical analysis of the present day distribution of the species confirms the phylogenetic validity of the proposed subdivisions, and shows that the subgenus Holostelidium originated in the southern hemisphere, while the subgenus Enteropodium is of boreal origin. An attempt is made to reconstruct the hypothetical ancestral crustaceous prototype, which approximates closely to certain forms of Toninia (Catillariales). The affinities of Stereocaulon are therefore with the Lecideaceae, and not with the Cladoniaceae, where it is commonly placed. The chemical compounds produced by Stereocaulon species are enumerated, and in order to simplify taxonomy in lichens generally, it is proposed to regard morphologically indistinguishable but chemically different individuals as chemical strains, and not as distinct species as has been the previous common practice.
THE SPLASH-CUPS OF POLYPORUS CONCHIFER
Authors: Brodie Harold J.
Published: August 2008

The cup-shaped structures produced by Polyporus conchifer are splash-cups from which oidia are thrown to a distance of four feet by raindrops. The oidia are developed on the inner surfaces of the cups in gelatinous masses. The jelly swells at once on being wetted and the cup is filled with oidia which germinate readily and give rise to dikaryotic mycelium. The cups are developed in late summer. From one rim of each cup the flat pore-bearing pileus grows out as the season advances and basidiospores are discharged from the pore layer. During winter, the flat pileus becomes detached from the cup and the latter persists until spring or longer and occasionally may regenerate a new pileus.The dispersal by rain of oidia from the cups of P. conchifer prolongs the reproductive period of the fungus.
CYTOGENETICAL RESPONSES OF CEREALS TO 2,4-D: I. A STUDY OF MEIOSIS OF PLANTS TREATED AT VARIOUS STAGES OF GROWTH
Authors: Unrau John , Larter E. N.
Published: August 2008

Different plots of Olli barley, Thatcher common wheat, and Stewart durum wheat were each sprayed with a single treatment of 2,4-D. The spraying was done at three-day intervals from emergence to heading time in order to study the effect of the herbicide when applied to plants at various developmental stages. An ester formulation equivalent to 12 oz. acid in 40 gal. of water per acre was used in all cases. Meiosis was studied in spikes obtained from plants of treated and untreated check plots. This material was fixed and stored in Carnoy's Fluid A. Meiotic irregularities were induced by the treatment in some plants of each of the three cereals at all stages of growth. The percentages of abnormal metaphases and anaphases ranged from 0.0 to 35.3 in barley, 0.0 to 33.3 in durum wheat, and 0.0 to 25.0 in common wheat. Chromosomal aberrations were of various types including bridges, fragmentation, asynapsis, aneuploidy, polyploidy, chain and ring formation, and in many cases extreme stickiness of chromosomes. These aberrations are similar to those induced by X irradiation or other mutagens. It is important to determine whether chromosomal aberrations in treated plants are transmissible and also whether gene mutations have been induced. Cytogenetical studies are under way on progenies of treated plants.
THE DECOMPOSITION OF DITHIOCARBAMATE FUNGICIDES, WITH SPECIAL REFERENCE TO THE VOLATILE PRODUCTS
Authors: Lopatecki L. E. , Newton W.
Published: August 2008

The gaseous exchange accompanying decomposition of dithiocarbamate fungicides was measured in the Warburg manometer. Sodium diethyl dithiocarbamate decomposed under slightly acid conditions, producing carbon disulphide and a salt of diethylamine. The insoluble zinc and iron salts of dimethyl dithiocarbamic acid also decomposed in a similar fashion, but no carbon disulphide was given off from the more stable copper salt of this compound. The rate of decomposition of these metallic salts fell in the following decreasing order:[Formula: see text]Disodium ethylene bis-dithiocarbamate (nabam) decomposed under slightly acid conditions to produce approximately equal volumes of hydrogen sulphide and carbon disulphide, and presumably left a residue of ethylene thiourea. In distilled water, on the other hand, nabam underwent a slow basic hydrolysis and oxidation, with absorption of approximately two volumes of oxygen, and evolution of one volume of carbon disulphide. Apparently the sulphur fraction which is evolved as hydrogen sulphide from nabam under acid conditions is, under basic conditions, oxidized in solution by atmospheric oxygen to sulphate.
CARBON AND OXIDATION–REDUCTION BALANCES AND THE ESTIMATION OF FERMENTATION EFFICIENCIES OF AEROBIC FERMENTATIONS
Authors: Shu P. , Thorn J. A.
Published: August 2008

A method for preparing carbon and oxidation–reduction balances of aerobic fermentations is described. In spite of the complexity of the microbial cell, relatively few and simple analyses of the material are necessary for the purpose of constructing the balances. To test the method, balances were made on citric acid and ustilagic acid fermentations. Excellent results were obtained. Based on the principle of material balance, a number of formulae for calculating the fermentation efficiency and respiratory loss have been established for fermentations involving substrates and products of varied oxidation–reduction status. Limitations of the method and formulae are also discussed. Results obtained by the described methods and equations are of value in correlating the various processes occurring in an aerobic fermentation and in providing an over-all picture of the fermentation.
THE COMPOSITION OF AIR IN TRUNKS OF SUGAR MAPLE IN RELATION TO DECAY
Authors: Thacker D. G. , Good H. M.
Published: August 2008

The internal air of maple trunks was found to vary considerably in composition, particularly in decaying trees. In all cases carbon dioxide occurred in much larger, and oxygen in smaller amounts than in the atmosphere. Carbon dioxide content was highest in the summer and lowest in midwinter, oxygen varying reciprocally. Diurnal variations were also noted. Growth of maple rot fungi on malt agar was favored by carbon dioxide in concentrations found in living trees. In several cases, optimum concentrations were of the order of 10%, growth being approximately double that in carbon dioxide-free air. Oxygen had little effect within the range of concentrations occurring in trees. It is concluded that aeration is probably not an important factor in the development of decay, poor aeration tending to be stimulating rather than inhibiting.
PHLORETIN: AN ANTIBACTERIAL SUBSTANCE OBTAINED FROM APPLE LEAVES
Authors: MacDonald Russell E. , Bishop Charles J.
Published: August 2008

A crystalline antibacterial substance isolated from apple leaves has been identified as phloretin. It has been shown to inhibit the growth of a number of Gram-positive and Gram-negative bacteria. The activity of the compound is bacteriostatic in nature and is shown in concentrations as low as 30 p.p.m. Its antibacterial action may be related to inhibition of the uptake of phosphorus by the bacterial cell.
PRODUCTION OF VITAMIN B12 BY RHIZOBIUM SPECIES
Authors: Burton Margaret O. , Lochhead A. G.
Published: August 2008

A study was made of the capacity for synthesis of vitamin B12 by 70 strains representing six species of Rhizobium, namely, R. meliloti, R. trifolii, R. leguminosarum, R. japonicum, R. lupini, and R. phaseoli. Rhizobium meliloti was sharply distinguished from the other species by its ability to produce significantly higher quantities of the vitamin, one strain producing, under the experimental conditions, over 1000 mμgm. per ml. of culture liquid. The remaining species did not show significant differences in B12 synthesizing capacity. No correlation was noted between vitamin-producing capacity and effectiveness of the individual strains with respect to nitrogen fixation.
WINTER CROWN ROT OR SNOW MOLD OF ALFALFA, CLOVERS, AND GRASSES IN ALBERTA: II. FIELD STUDIES ON HOST AND VARIETAL RESISTANCE AND OTHER FACTORS RELATED TO CONTROL
Authors: Cormack M. W.
Published: August 2008

Many overwintering cultivated and native plants proved susceptible to the low-temperature basidiomycete which causes winter crown rot or snow mold of forage legumes and grasses in Alberta. Tests were made by inoculation in the late fall, or by planting in infested land. In the legumes, high resistance was found only in Medicago falcata and a Siberian strain of Trifolium pratense. T. hybridum, Melilotus spp., and the commonly grown varieties of alfalfa were particularly susceptible. Bromus spp. and Agropyron spp. proved highly resistant. Resistance was moderate in Elymus spp., Poa pratensis, and Festuca elatior; and slight in F. rubra and Phleum pratense. Agrostis alba, winter wheat, and winter rye were highly susceptible. In tests on horticultural plants, rhubarb and chives appeared to be immune; raspberry, peony, and columbine were resistant; and strawberry, parsnip, iris, and tulip were highly susceptible. A wide range of native plants and weeds suffered severe damage, and only Thalictrum spp. proved highly resistant. Shrubs and trees were not attacked.Following severe damage, crop rotation proved to be essential for the control of winter crown rot. The pathogen did not persist in the soil to any extent for longer than two to three years in land which was summer-fallowed or planted to annual crops or resistant grasses. Brome and other resistant grasses proved helpful in maintaining forage stands. Fertilizer treatments did not reduce the damage. Uncut tops and debris favored spread of the disease in alfalfa stands.
OBSERVATIONS ON THE HOST RANGE OF CUSCUTA EUROPEA AMONG THE COMPOSITAE
Authors: Gaertner Erika E.
Published: August 2008

One hundred and twenty-eight species of 44 genera of the family Compositae were examined as to their susceptibility to the dodder, Cuscuta europea. The indices presented are thus to supply additional data about host preference in the genus Cuscuta.
THE PROTEOLYTIC ENZYMES OF MICROORGANISMS: IV. PARTIAL PURIFICATION AND SOME PROPERTIES OF EXTRACELLULAR PROTEASE FROM MORTIERELLA RENISPORA DIXON-STEWART
Authors: Wetter L. R.
Published: August 2008

A protease concentrate was obtained from the culture medium of Mortierella renispora Dixon-Stewart (PRL 26) by repeated precipitation with ammonium sulphate. The specific activity of the mold protease compared favorably with that of crystalline trypsin. The pH optimum was broad, with a maximum at a pH of 7.5 when hemoglobin was used as the substrate. A study of the pH stability characteristics showed that it was stable over a wide range (4.9 to 9.5) at 1 °C. and 25 °C. Ferrous ions caused a considerable increase in the activity of the enzyme preparations, other metals were ineffective as activators.
STUDIES IN FOREST PATHOLOGY: IX. FOMES IGNIARIUS DECAY OF POPLAR
Authors: Riley C. G.
Published: August 2008

Decay of Populus tremuloides Michx. and P. grandidentala Michx. caused by Fomes igniarius var. populinus (Neuman) Campbell was studied at the Petawawa Forest Experiment Station, Ont., in stands up to 70 years of age. In eight [Formula: see text] acre sample plots representing stands 60 to 70 years old, 28.6 to 69.2% of the trees were infected; the percentage of decay in the gross merchantable cubic volume was 3.2 to 14.3 in the decayed trees, and 0.9 to 8.1 in decayed and sound trees considered together. Equally variable results were obtained in younger age classes. No relation between decay and site could be established on the basis of actual cubic volume, but when the trees were measured in board feet a slightly higher percentage of cull occurred on the poorer sites, owing at least partly to the smaller trees. Net periodic increment continued to increase in the 60–70-year age class on favorable sites. Sporophore-bearing trees died in the second and third years after being girdled, and the original number of mature living sporophores was reduced to 13% six years after girdling. On similar trees which were felled and left intact on the ground during the same period the number of sporophores increased. Artificial inoculations in both sapwood and heartwood of living trees resulted in the development of typical decay from which the pathogen was re-isolated. Observations on 5 to 18 sporophores from May 4 to June 30 of the following year proved that sporulation of F. igniarius is continuous from early spring to late autumn. There is not necessarily any period of inactivity during which new tube layers are formed, though irregular periods of one to several days without sporulation are common. Sporulation is favored by high relative humidity and high temperature. The lowest temperature at which sporulation was observed was 40° F.
STUDIES OF CANADIAN THELEPHORAGEAE: IX. A CULTURAL AND TAXONOMIC STUDY OF THREE SPECIES OF PENIOPHORA
Authors: McKeen Constance G.
Published: August 2008

Close relationship between Peniophora heterocystidia Burt, P. mutata (Peck) Höhn. & Litsch., and P. populnea (Peck) Burt is indicated by similarities in their fruit bodies, but specific separation is warranted by differences in color and thickness of fruit bodies and in shape and relative numbers of cystidia and gloeocystidia. In addition, P. populnea is restricted to the host genus Populus and P. heterocystidia to broad-leaved trees other than Populus. This separation is confirmed by recognizable differences in the cultural characters of the three species and by interfertility tests. Pairings between monosporous mycelia from individual fruit bodies have shown that all three species are hermaphroditic, self-sterile, and interfertile, and of the bipolar type of interfertility. Pairings between monosporous mycelia from fruit bodies of the same species have shown complete or partial fertility, while pairings between fruit bodies of the different species have demonstrated complete sterility. Cultures from fruit bodies typical of P. allescheri (Bres.) Sacc. & Syd. behaved like those from typical P. mutata, confirming the combination of the two species. In interfertility tests between cultures of P. mutata, isolates from Populus were completely interfertile, as were those from hosts other than Populus, but pairings between isolates from Populus and other hosts exhibited various degrees of incompatibility. Sizes of basidiospores and conidia in collections and cultures of P. mutata from Populus were slightly larger than in collections from other hosts, but differences were not considered sufficiently great to justify the establishment of a variety. Conidiophores and conidia are produced abundantly in cultures of all the species but were found in nature only in two collections of P. heterocystidia.
Response and Recovery of Brain Acetylcholinesterase Activity in Atlantic Salmon (Salmo salar) Exposed to Fenitrothion
Authors: Morgan M. J. , Fancey L. L. , Kiceniuk J. W.
Published: August 2008

Atlantic salmon (Salmo salar) parr were exposed to a number of concentrations of either technical grade fenitrothion or an operational formulation of the pesticide for 7 d or to the operational formulation for two, 24 h periods separated by 7 d. Brain acetylcholinesterase (AChE) activity decreased as concentration, of fenitrothion increased. Recovery period was directly related to amount of depression, with recovery of AChE from exposure to 0.004 μL/L fenitrothion taking less than 1 wk. Samples must be taken soon after spray operations to detect exposure to such low levels of fenitrothion through AChE monitoring.
Effects of Calcium and pH on the Reproductive Success of Amnicola limosa (Gastropoda)
Authors: Shaw Margo A. , Mackie Gerry L.
Published: August 2008

Field and laboratory experiments were designed to examine the relationship between water chemistry (especially pH and calcium) and the reproductive success of Amnicola limosa. Fecundity (no. eggs∙female−1) was positively correlated with lake buffering capacity (P = 0.002) in naturally occurring populations. We documented a 66% reduction in fecundity in lakes over a pH range of 7.6–5.8. However, fecundity was higher than expected in a highly-coloured, low-pH lake. The number of juveniles produced per egg was not related to any water chemistry variable (multiple R2 = 0.186). A laboratory experiment demonstrated that pH, and not calcium, was limiting embryonic development. All embryos held at pH 4.5 failed to hatch. Eggs held at pH 5.5 experienced reduced hatching success (P = 0.013) and delayed development (P < 0.001) compared with those held at pH 6.5. Length of newly hatched snails did not differ significantly between treatments (P = 0.891). The critical calcium concentration required for embryonic development in laboratory incubation lay between 0.14 and 1.11 mg∙L−1. This is well below the calcium concentration of acidifying lakes in south-central Ontario.
Territory Size as a Predictor of the Upper Limit to Population Density of Juvenile Salmonids in Streams
Authors: Grant James W. A. , Kramer Donald L.
Published: August 2008

We examined the old, but untested hypothesis that territory size limits the maximum population density of salmonids in streams. We used published data to derive an interspecific regression of territory size (m2) on fork length (cm) (log10 territory size = 2.61 log10 length—2.83, r2 = 0.87, n = 23). Growth and mortality trajectories of salmonid cohorts from eight experimental studies were compared to the maximum-density regression, the inverse of the territory–size regression. In shallow habitats, such as riffles and raceways, the cohort trajectories followed the maximum density regression quite closely and were consistent with the territory–size hypothesis. In addition, natural densities in eight other studies did not exceed the predicted maximum density and tended to fail within the 95% C.L. of the maximum-density regression. Data from shallow habitats, therefore, provide strong support for the territory–size hypothesis. A linear logistic response model showed that the probability of observing density-dependent growth, mortality, or emigration increased significantly with increasing values of an index of habitat saturation, developed from the territory–size regression. Our results suggest that the territory–size regression has practical value for predicting the maximum densities of stream-dwelling salmonids in shallow habitats and the occurrence of density-dependent population responses.
Genetic Variation in One Bottlenecked and Two Wild Populations of the Japanese Scallop (Patinopecten yessoensis): Empirical Parameter Estimates from Coding Regions of Mitochondrial DNA
Authors: Boulding Elizabeth C. , Boom John D. C. , Beckenbach Andrew T.
Published: August 2008

Restriction analysis of the mitochondrial genome of 16 Japanese scallop (Patinopecten yessoensis) provided unique genotypes for each individual, mostly due to length variation. Fragment length variation was common, probably because tandemly repeated elements of noncoding mtDNA mutate to a different number of copies at high rates. To accurately estimate genetic diversity, we used the polymerase chain reaction (PCR) to selectively amplify coding mtDNA fragments and performed restriction analysis on these. Four pairs of PCR primers were used to amplify fragments encoding: (1) most of ATP synthetase subunit 6 and most of cytochrome c oxidase subunit 3, (2) part of cytochrome b apoenzyme, (3) tRNA for threonine, and (4) most of the large (16S) ribosomal gene. We used this technique to compare the genetic diversity of a population bred in a small experimental hatchery in British Columbia for three generations with its wild source population at Mutsu Bay, Aomori, Japan, and with a second wild population at Uchiura Bay, Hokkaido, Japan. The three populations were similar in the frequency distributions of the 11 mitochondrial clonal lines. This suggests that the experimental hatchery stock was not severely inbred and that gene flow between the two wild Japanese populations has been sufficient to prevent divergence.
Use of Path Analysis to Investigate Mercury Accumulation in Brown Trout (Salmo trutta) in Norway and the Influence of Environmental Factors
Authors: Fjeld Eirik , Rognerud Sigurd
Published: August 2008

We studied relationships between environmental factors and mercury accumulation in resident brown trout (Salmo trutta) in 25 lakes in Norway. Our survey showed that mercury concentrations in fish are elevated in areas receiving high atmospheric depositions of mercury. A path analysis revealed that the concentrations of total organic carbon had a critical influence on the bioaccumulation of mercury. This reflects the role of humic matter in the transportation of mercury to lake water and sediments, and perhaps also a stimulating effect on the microbial methylation of mercury. Lake depth influenced the concentration of mercury in sediments, probably due to the complexation of mercury with sedimenting humic matter. The effect of such sediment on mercury concentrations in fish indicated that there exists a concentration-dependent production and release of methyl mercury to the biota. Selenium deposited from the atmosphere seemed to lower the bioavailability of mercury to fish. No effect of pH could be detected. The strong effect of total organic carbon implies that even moderate atmospheric deposition rates may result in relatively high mercury levels in fish, if other local environmental factors favour this.
Use of Biochemical Genetic Markers to Discriminate between Adductor Muscles of the Sea Scallop (Placopecten magellanicus) and the Iceland Scallop (Chlamys islandica)
Authors: Kenchington E. , Naidu K. S. , Roddick D. L. , Cook D. I. , Zouros E.
Published: August 2008

Three biochemical techniques were applied to adductor muscles of Placopecten magellanicus and Chlamys islandica, two commercially important scallops, to search for species-specific genetic markers. Allozyme electrophoresis identified two enzyme systems, mannose phosphate isomerase and glutamic oxaloacetate transaminase, which appear to be diagnostic. Sequencing of the 18S rRNA gene in each species showed 15 nucleotide differences over 1815 base pairs. Digestion of the gene with the restriction enzyme XHO I released two fragments in Placopecten and three in Chlamys. All three techniques could be developed for management purposes as part of an enforcement programme to identify illegally caught scallops.
Occurrence of Sea Lamprey,Petromyzon marinus, in a Newfoundland River, with Additional Records from the Northwest Atlantic
Authors: Dempson J. B. , Porter T. R.
Published: August 2008

Information on adult and larval sea lamprey, Petromyzon marinus, from Terra Nova River, Newfoundland, provides the first documented occurrence of a spawning population of lamprey from this province. Sea lamprey captured on the spawning grounds in mid-July 1989 ranged in length from 530 to 687 mm. Larvae collected in 1989 and 1990 ranged in length from 22 to 176 mm, and specimens were found distributed as far as 5 km below the only known spawning area. Length of larval specimens displaying signs of metamorphosis ranged from 135 to 170 mm. The length frequency distribution of sea lamprey larvae collected in 1990 is suggestive of multiple age classes. Information on the marine distribution of sea lamprey is provided from 24 records of captures in marine waters adjacent to Newfoundland.
Interactive Effects of Nutrient Availability and Light Levels on the Periphyton Composition of a Large Oligotrophic Lake
Authors: Marks Jane Claire , Lowe Rex L.
Published: August 2008

We investigated the effects of nitrogen, phosphorus, and light on periphyton in a clear oligotrophic lake. Experimental treatments consisted of three levels each of nitrogen, phosphorus, and light in a three-way factorial design. Nitrogen and phosphorus concentrations were manipulated using nutrient-diffusing clay substrates; light levels were manipulated with shade cloth. Periphyton biovolume and cell densities increased significantly with both nitrogen and phosphorus enrichment but were not affected by shading. Phosphorus enrichment increased periphyton accumulation only when nitrogen levels were high, indicating a significant interactive effect between nitrogen and phosphorus. Differences in species composition among treatments were mostly due to changes in the diatoms Nitzschia palea and Rhopalodia gibba. Ambient and phosphorus-enriched substrates were dominated by R. gibba, which contains a nitrogen-fixing endosymbiont, and blue-green algae. Nitrogen enrichment and nitrogen and phosphorus in combination resulted in an assemblage dominated by N. palea. Unshaded and highly shaded substrates were dominated by N. palea and Achnanthes minutissima, but the medium-shade substrates were dominated by R. gibba.
Direct and Indirect Effects of Fish Predation on the Replacement of a Native Crayfish by an Invading Congener
Authors: Mather Martha E. , Stein Roy A.
Published: August 2008

In Ohio streams, the crayfish Orconectes rusticus is replacing O. sanborni, and herein we test how predators influence this replacement. In a field survey, crayfish were scarce when fish were abundant, suggesting that predators can adversely affect these prey. In laboratory experiments, we examined underlying mechanisms for this inverse relationship; specifically, we tested how crayfish species, adult aggression, and habitat heterogeneity influenced the predator–prey interaction. In a laboratory stream, smallmouth bass (Micropterus dolomieu) ate similar numbers of equal-sized O. rusticus and O. sanborni, but when sizes mimicked those in the field (i.e., O. rusticus 4 mm > O. sanborni), fewer O. rusticus were eaten. Fish also reduced juvenile activity and behaviors whereas adult aggression increased the frequency of these risky responses. More affected by adult crayfish, O. sanborni should suffer disproportional predation where adults and juveniles interact. Thus, fish predators should increase replacement rates and adult aggression should further accelerate this process. Manifested through crayfish size, both indirect and direct predator effects contribute to the replacement of O. sanborni by O. rusticus.
Changes in Prey Fish Populations in Western Lake Erie, 1969–88, as Related to Walleye, Stizostedion vitreum, Predation
Authors: Knight Roger L. , Vondracek Bruce
Published: August 2008

Relative abundance of the total prey fish community in the western basin of Lake Erie varied little from 1969 to 1988, but species composition changed significantly. Soft-rayed fishes such as emerald shiner, Notropis atherinoides, spottail shiner, N. hudsonius, and alewife, Alosa pseudoharengus, declined significantly after 1977 whereas only one spiny-rayed species, white bass, Morone chrysops, declined over the same period. Trout-perch, Percopsis omiscomaycus, a relatively abundant species rarely eaten by piscivores in this system, experienced only minor shifts in abundance between 1969 and 1988. Although several factors could be responsible for the shift in species composition, predation by increasingly abundant walleye, Stizostedion vitreum, played a major role. Walleye prefer to eat soft-rayed fishes; thus, observed shifts in the community match expectations of selection noted in the diet. We suggest that management goals focusing primarily on walleye affected not only the targeted species but the entire fish community of western Lake Erie.
A novel and efficient synthesis of bis(benzofuranyl)methanes and 2-benzofuran-1-nitroalkanes catalyzed by Bi(OTf)
Authors: Chen Ren Er , Wang Yan Li , Chen Zhi Wei , Su Wei Ke
Published: August 2008

Bismuth (III) triflate-catalyzed Friedel-Crafts reactions between benzofuran and aldehydes in different solvents were investigated. Bis(benzofuranyl)methanes were obtained with good yields when acetonitrile was used as solvent, while in the case of nitromethane the multi-component reaction products, 2-benzofuran-1-nitroalkanes, were formed under similar conditions. A plausible mechanism is given.Key words: benzofuran, aldehyde, bis(benzofuranyl)methanes, Bi(OTf)3, 2-benzofuran-1-nitroalkane.
Numerical taxonomy of hybridizing Lepomis (Centrarchidae) in Lake Opinicon, Ontario
Authors: Colgan P. W. , Ballantyne P. K. , Wilson M. V. H.
Published: August 2008

Cluster analysis of hybridizing Lepomis gibbosus (pumpkinseedsl and L. macrochirus (bluegills)collecled in Lake Opinicon, Ontario, using data on 20 morphological characters in 108 specimens, revealed three groups, the two parental species and a group of hybrids, all of which were clearly separated by discriminant analysis. Discriminant functions based on the red opercular flap, the pharyngeal dentition, and body depth, correctly assigned all specimens to the appropriate group. Discriminant functions are also reported for external characters only, but the assignment to groups is not perfect. A sample of L. gibbosus, taken from a locality in which other Lepomis species were not present, was found to be very similar to the Lake Opinicon sample of this species. The hybrids of Lake Opinicon do not appear to backcross frequently with the parental species, possibly because of nonintermediacy in reproductive behavior.
Observations on the freeze-cleaved ultrastructure of fenestrated endothelial cells in mouse thyroid
Authors: Nohr Carl W. , Costerton J. W. , Henderson Nancy E.
Published: August 2008

The endothelium of the capillaries in the thyroid of the mouse was found to be fenestrated. These fenestrae are similar to those described in mouse kidney, rat kidney, and rat liver in their size and distribution, and they occupy about 17% of the areas in which the endothelial cells are < 100 nm thick. Where the cells are > 100 nm thick, numerous smooth-surfaced vesicles are seen in the cytoplasm. It is suggested that both the fenestrae and the vesicles play a role in transport across the capillary wall.
Social behavior and feeding ability of two phenotypes of Gasterosteus aculeatus in relation to their spatial and trophic segregation in a temperate lake
Authors: Larson Gary Lee
Published: August 2008

Significant differences in morphology, behavior, spatial distribution, and feeding habits were found between limnetic and benthic forms of the threespine stickleback (Gasterosteus aculeatus) in a small British Columbia lake. The social behavior and feeding ability of each form were studied experimentally to provide a basis for determining the mechanisms of spatial and trophic segregation observed in the lake. The hypothesis that the benthic form was solitary, aggressive, and attracted to lake-bottom cover, and the limnetic form was gregarious, nonaggressive, and attracted to lake-surface cover was supported by the laboratory experiments. Furthermore, the hypothesis that the limnetic form could feed more successfully on zooplankton, and the benthic form on macrobenthos was supported by the experiments. The benthic form spent significantly more time in search of food in lake-bottom cover than did the limnetic form. It is suggested that the two forms of stickleback had undergone extensive adaptations to very different habitats in the lake, and therefore, their spatial and food segregation was not maintained entirely by interactions, but at least partially by inherent behavioral differences.
Fecundity of mooneye, Hiodon tergisus, in the Assiniboine River
Authors: Glenn C. L. , Williams R. R. G.
Published: August 2008

Age at sexual maturity, seasonal gonadal development, and fecundity estimates of mooneye were determined from 695 samples captured in the Assiniboine River between November 17, 1972, and November 2, 1973. Most mooneye became sexually mature in their 4th (III +) or 5th (IV +) year of life, with more males mature at age III + than females. During 1973, spawning began after May 8 and was completed by June 12. The peak spawning activity occurred during mid-May when water temperatures ranged from 10 to 13 °C. All age groups of sexually mature females had rapid ovarian development during the summer months with about 80% of maximum ovarian weight present by October 17. Ripe ova have a mean diameter of 1.98 ± 0.07 mm. The mean annual total fecundity of Assiniboine River mooneye was about 5000–9000 ova per female. The mean annual relative fecundity was about 2000–2400 ova per 100 g body weight.
Reproductive growth in normal, allatectomized, median-neurosecretory-cell-cauterized, and ovariectomized females of Melanoplus sanguinipes
Authors: Gillott C. , Elliott R. H.
Published: August 2008

Changes in the weight of the whole insect, fat body, and ovary during successive gonotrophic cycles have been measured. The effects of ovariectomy, cautery of the median neurosecretory cells (mNSC), or removal of the corpora allata (CA) on the development of the fat body and reproductive system have also been observed.After an initial period of somatic growth, changes in body weight are very largely due to growth of the proximal oocytes and to oviposition. Yolk deposition begins when the oocytes are1.0 mm long and occurs most rapidly during the final stages of their development. Vitellogenesis begins in the penultimate oocytes when the proximal oocytes are 3.0–3.5 mm long. Ovariectomy results in a significant increase in the weight of the fat body. Removal of the CA prevents oocyte development beyond the 1-mm stage and production of secretion in the lateral oviducts. Both effects can be reversed by treating operated insects with juvenile hormone. Cautery of the mNSC, provided it is carried out within 3 h of emergence, also inhibits oocyte growth and delays the appearance of secretion in the lateral oviducts.
A model of foregut activity in the blowfly Phormia regina Meigen. II. Peristalsis in the crop duct during the crop-emptying process
Authors: Thomson A. J. , Holling C. S.
Published: August 2008

The effects of the mechanical properties of the crop-duct musculature on the production of pressure increase in the crop duct by peristalsis are examined by the application of the model of Thomson and Holling to a mechanical analogue of the crop duct. Behavior of the crop-duct model in terms of the initiation of both peristalsis and reverse peristalsis reflects the observed behaviour of the crop duct of Phormia regina. Although the properties of the peristaltic wave such as amplitude, wavelength, and velocity vary in a complex manner with crop-duct volume, and also with the distance which the peristaltic wave has travelled, the structure of the model accurately reflects these variations.
Thyroxine concentrations in plasma of normal and hypophysectomized hagfish, Myxine glutinosa (Cyclostomata)
Authors: Henderson Nancy E.
Published: August 2008

The influence of the pituitary on thyroid function in hagfish was investigated using the direct approach of hypophysectomy. Plasma thyroxine (T4) concentration, measured by competitive protein-binding analysis, was used as the index of thyroid activity. Two months postoperatively, T4 levels were similar in hypophysectomized, partially hypophysectomized, and sham-operated fish, but the levels were reduced to about 50% of the titres in intact controls. No morphological changes were observed in the thyroid tissue of any of the operated groups of fish. The experiment provides no evidence for the existence of a pituitary thyrotropin in hagfish.
The life cycle of Eubranchipus bundyi (Forbes) (Crustacea: Anostraca) in a temporary vernal pond of Alberta
Authors: Daborn Graham R.
Published: August 2008

The life cycle of Eubranchipus bundyi (Forbes) in a vernal temporary pond is described for 1969. Hatching was restricted to 6–7 days immediately after spring thaw in early April. Growth was rapid for 12 days, reaching a maximum of 0.68 mm per day in males and females on the 13th day. Maximum daily dry-weight increment was 16 μg. Maximum lengths were 12.9 mm for a male and 13.8 mm for a female, but mean lengths of mature animals varied around 10.6 mm. A brief cessation of growth in late April corresponded to a sudden drop in temperature; otherwise, the mean growth curve was well fitted by the logistic formula.Mean clutch size was 22, and no significant relationship could be found between female length and egg number. Most females died after producing one clutch. High mortality of males preceded that of females.
Growth and development of larvae and adults of Tipula sacra Alexander (Insecta: Diptera) in a series of abandoned beaver ponds
Authors: Pritchard G.
Published: August 2008

Collections of all stages of the crane fly, Tipula sacra have been made over a period of years from a series of abandoned beaver ponds in the Kananaskis Valley, Alberta. The growth of larvae was followed by head-capsule measurements and weights. Eggs hatch within a month; first-instar larvae grow rapidly and enter the second instar after a few weeks. The second instar may last for 3 months and the third instar usually lasts for 6 months, including the first winter. Most larvae spend almost a full year in the fourth instar and overwinter for a second time. However, there was much variation in growth rate within the population. Adult emergence curves were consistent in form in 4 years. Each spanned a period of just over 2 months, although individual adults lived for only a few days. These curves snowed two peaks, the second of which contained 15–20% of the year's emergents. These two groups may represent different cohorts that have grown at different rates, suggesting that the life history may be semivoltine or univoltine. The sex ratio changes from about 1:1 in the third instar to 2:1 in favor of males in the late fourth instar, pupa, and adult.
Maintenance of spermatogenesis and seminal vesicles in the hypophysectomized catfish, Heteropneustes fossilis (Bloch): effects of ovine and salmon gonadotropin, and testosterone
Authors: Nayyar S. K. , Keshavanath P. , Sundararaj B. I. , Donaldson E. M.
Published: August 2008

The effects of 20-day treatment with ovine luteinizing (LH) and follicle-stimulating hormone (FSH), partially purified salmon gonadotropin (SG-G100), and testosterone were investigated by evaluating the maintenance of spermatogenesis in the testes and secretory activity in the seminal vesicles of the catfish, Heteropneustes fossilis, after hypophysectomy during the prespawning period. Low doses of LH (0.1 or 1 μg per fish) neither maintained spermatogenesis in the testes nor secretory activity in the seminal vesicles, whereas a higher dose of LH (10 μg per fish) maintained spermatogenesis qualitatively, and sustained the seminal vesicles in a moderately secretory state. One microgram of SG-G100 per fish partially maintained spermatogenesis but the seminal vesicles showed poor maintenance. Ten micrograms of SG-G100 per fish not only sustained spermatogenesis qualitatively and quantitatively, but also induced spermiation; the seminal vesicles, though enlarged, contained little secretion, indicating possible reduction through spermiation. FSH did not maintain spermatogenesis in the testes or secretory activity in the seminal vesicles. Testosterone (10, 100, or 500 μg per fish) had a dose-dependent maintenance response in the testes and seminal vesicles; with 500 μg of testosterone the maintenance of testes and seminal vesicles was similar to that in initial intact controls, with no indication of spermiation.
Observations on the social behaviour of the Chinese hamster, Cricetulus griseus
Authors: Skirrow Margaret H. , Ryšan Milada
Published: August 2008

Social behaviour between individuals and between mixed-sex pairs of Cricetulus griseus was observed in large floor pens. The species exhibited strong intolerance of conspecifics. Females were highly aggressive and dominant over males. Their presence seemed to inhibit aggression between males. Marking appeared to be positively correlated with dominance in females, and may have served for sexual identification in mixed-sex encounters. The site familiarity imposed by the experimental conditions had no effect on the outcome of encounters. Areas of exclusive occupancy were not recognized and defended, although the animals did show respect for nest sites. Aggressive behaviour was normally elicited by violation of an individual distance of about 15 cm.The absence of contact-promoting behaviour and preliminary warnings to attacks suggests a solitary, dispersed existence of C. griseus. The characteristics of a solitary species, such as a burrowing pattern of life, food caching, and a brief period of pair formation, are discussed in relation to earlier studies on the social organization of rodents.
Glycogen pools in the arterial thoracic retia of the narwhal, Monodon monoceros, and their possible significance
Authors: Vogl A. Wayne , Fisher H. Dean
Published: August 2008

Ultrastructural observations of glycogen pools in the arterial walls of the thoracic retia are reported in the narwhal, Monodon monoceros. The possible significance in blood glucose regulation is briefly discussed.
Studies on Ergasilus labracis Krøyer (Cyclopidea: Ergasilidae) parasitic on striped bass, Morone saxatilis, from the lower Chesapeake Bay. I. Distribution, life cycle, and seasonal abundance
Authors: Paperna I. , Zwerner D. E.
Published: August 2008

Information on the distribution, life cycle, and seasonal abundance of the copepod Ergasilus labracis Krøyer, parasitic on the gills of lower Chesapeake Bay striped bass, Morone saxatilis (Walbaum), is presented after a 12-month survey. The overall prevalence of E. labracis was 90% in all localities sampled and it was found to be as euryhaline as its host; it has been found in salinities from 0.l‰ to 32.0‰. E. labracis was present and reproductively active throughout the year, suffering only a temporary slowdown in egg production at the beginning of the winter. Peak invasion of striped bass gills by infective larvae occurred during April and May; minor peaks were also recorded during July and October. The free-living stage was estimated to last as long as 6 weeks during early spring. Duration of other developmental stages was also extrapolated. Attempts to rear larvae in the laboratory past the metanauplius stage failed. Larvae could be kept for a maximum of 23 days after hatching if fed nannoplankton and kept at 20 °C in river water of 16–18‰.
Rôle de l'épiphyse dans la migration du pigment épithélial rétinien chez quelques Téléostéens
Authors: Chèze Genevieve , Ali M. A.
Published: August 2008

Role of the pineal organ (epiphysis) in the migration of the retinal epithelial pigment in response to changes in ambient light conditions was investigated. Pinealectomy, and section of the optic nerves and the spinal cord enable us to conclude that the influence of the nervous system is minimal or lacking in this phenomenon, which seems to be controlled mainly by a humoral factor. Pigment migration within retinal cells is directly affected by intraocular injection of melatonin. The results suggest that a humoral factor of the pineal organ, possibly melatonin, may play a role in the physiological control of retinal pigment-granule movements.
Relative toxicity of organic and inorganic compounds of selenium to newly hatched zebrafish (Brachydanio rerio)
Authors: Niimi A. J. , Laham Q. N.
Published: August 2008

Newly hatched zebrafish (Brachydanio rerio) were exposed to eight compounds of selenium to establish their relative toxicities. The compounds examined included the organoselenides of methionine and cystine, the inorganic selenite salts of sodium and potassium, selenium dioxide, and the inorganic selenate salts of calcium, sodium, and potassium. The selenite compounds were more toxic to zebrafish than the selenates; the 96-h concentrations lethal to 50% of the fish ranged from 15 to 23 μg/ml for the selenites and from 81 to 82 μg/ml for potassium and sodium selenate. The limited solubility of selenocystine and the significant losses of selenomethionine from the test solutions did not allow comparable estimates to be made for the selenides. These differences in toxicity between the selenites and selenates were also demonstrated when selenium levels required to produce a 5% mortality at the end of the 10-day observation period were estimated. There was a marked difference in toxicity between the organoselenides at this level, with the toxicity of selenocystine being similar to the selenates, and selenomethionine being the most toxic of all the compounds tested.The probable role of selenium in the aquatic environment is also examined. The increasing awareness of this potentially significant pollutant, and its antagonistic nature with seven toxic or potentially toxic elements is also noted.
The influence of TSH and ACTH on purine and pteridine deposition in the skin of rainbow trout (Salmo gairdneri)
Authors: Premdas F. H. , Eales J. G.
Published: August 2008

The specific activities (s.a.) and levels of skin purines and pteridines were determined in 1-year-old rainbow trout that were injected with [14C]glycine and treated for 20–28 days with bovine thyroid-stimulating hormone (TSH) or adrenocorticotropic hormone (ACTH). TSH increased significantly the s.a. and levels of guanine and hypoxanthine, but had no effect on these parameters for guanosine monophosphate (GMP), biopterin, 2-amino-4-hydroxypteridine (AHP), and ichthyopterin. The s.a. of isoxanthopterin (IXP) was significantly decreased. ACTH increased significantly the s.a. and levels of GMP, biopterin, AHP, IXP, and ichthyopterin. The s.a. and levels of guanine and hypoxanthine were not altered significantly. Thus TSH promotes purine synthesis with no significant change in the synthesis of most pteridines, while ACTH promotes pteridine synthesis with no significant change in purine synthesis. These observations on trout skin do not favour a previously advanced generalization that purine and pteridine biosynthetic pathways compete for a common substrate.
Protoariciella oligobranchia new species (Orbiniidae) and six new records of Orbiniidae, Questidae, and Paraonidae (Annelida, Polychaeta) from British Columbia
Authors: Hobson Katharine D.
Published: August 2008

Protoariciella oligobranchia n.sp. is described from shell–gravel in the intertidal zone in Victoria, British Columbia. Orbiniella nuda, Scoloplos (Haploscoloplos) panamensis, Questa caudicirra, Aricidea assimilis, Aricidea minuta, and Paraonella platybranchia are briefly described and newly recorded from British Columbia.
Experimental infection of mammals with larval Echinocephalus sinensis (Nematoda: Gnathostomatidae) from oysters (Crassostrea gigas)
Authors: Ko Ronald C.
Published: August 2008

Seasonal variations were observed in Echinocephalus sinensis infections in 1159 Crassostrea gigas examined in Hong Kong in 1974. The highest incidence and intensity of infection was recorded in August. Worms recovered at various times during the year from naturally infected oysters were fed to 37 kittens, 11 monkeys, and two puppies, but infections were successful only with larvae collected from August to October. It is suggested that the infectivity of E. sinensis to mammals may be dependent on the ambient temperature. Some worms penetrated the gastrointestinal tract and underwent a random visceral migration in mammals. Worms were located in many organs of three kittens that died 16–30 h postinfection. Degenerating worms were found in a fibrous nodule in the stomach wall of a monkey examined 14 days postinfection; one worm was also recovered from the lung. The histopathology of the infection is briefly described and the possibility of E. sinensis infecting man is discussed.