bluuebunny/crossref_metadata_2025 huggingface dataset:
FACTORS GOVERNING ZOOSPORE RESPONSES OF PHYTOPHTHORA MEGASPERMA VAR. SOJAE TO PLANT ROOTS
Authors: Ho H. H. , Hickman C. J.
Published: August 2008

In the presence of plant roots, zoospores of Phytophthora megasperma var. sojae reacted in general as do other fungal zoospores: they were attracted to, and trapped in the immediate vicinity of the root surface, on which they encysted rapidly. Encysted zoospores formed a continuous sheath around the root, thickest just behind the root tip. Cyst germination was stimulated. Germ tubes were always initiated from the side of cysts closest to the root and grew towards it. In addition, a new feature was observed, suppression of repeated emergence of zoospores. Zoospore accumulation was nonspecific with respect to host and non-host, resistance, and susceptibility.Tests with exudates and extracts from roots of resistant and susceptible soybean varieties and a non-host, pea, confirmed the chemical nature of the stimulus inducing these responses. Zoospores observed in an electric field were not attracted towards either pole, but they were trapped and encysted rapidly around the negative pole. Cyst germination was not stimulated. Nevertheless, since encystment was more pronounced on root exudate agar mounted on the negative pole, electric charges on roots may also contribute to inducing early encystment of zoospores there.In an investigation of ions on zoospore responses, with ionic resins, all phases of zoospore response to roots, with the exception of attraction, occurred in the presence of hydrogen resin particles.
INTRAHYPHAL HYPHAE IN THE GENUS LINDERINA
Authors: Chan Christina , Stephen R. C.
Published: August 2008

The origin and development of intrahyphal hyphae in two species of Linderina are described. This is only the second record of endohyphae production by a Phycomycete. Injury and aging of the mycelium were factors stimulating production of intrahyphal growth. The evolutionary significance of intrahyphal hyphae growth in the genus Linderina is briefly discussed.
A RADIANT ENERGY METER AND INTEGRATOR FOR PLANT GROWTH STUDIES
Authors: Brach E. J. , Mack A. R.
Published: August 2008

An instrument designed to indicate, record, and integrate radiant energy sensed by an Eppley thermopile is described. The output of the thermopile is amplified by a d-c. operational amplifier. The amplified output is connected to a meter or a recorder and totalized by an integrator. The output is calibrated in Ly min−1 and the sensitivity in the three recording modes is better than 0.02 Ly min−1.
THE EFFECT OF LEAF WATER BALANCE ON THE SUSCEPTIBILITY OF FRENCH BEAN TO TOBACCO NECROSIS VIRUS
Authors: Kimmins W. C. , Litz R. E.
Published: August 2008

French beans were germinated under constant temperature, relative humidity, and day period, and were transferred to Hoagland's culture solution. Variations of the preinoculation treatment were begun at an age of 10 days for a period of 24 h. Treatments were selected which would induce turgor changes in the primary leaves.It was observed that susceptibility to tobacco necrosis virus infection was increased by preinoculation conditions of continuous darkness, high relative humidity, and low suction tension of the culture solution. Susceptibility was lowered by preinoculation conditions of continuous light, low relative humidity, and high suction tension of the culture solution.Diffusion pressure deficit, osmotic pressure, and turgor pressure measurements were made with the primary leaves at time of inoculation. Considerable agreement was noted between turgor changes and susceptibility.Preinoculation treatments such as darkening will alter susceptibility through changes in turgor pressure. It is suggested that there may be a direct effect of leaf turgor on the number of infectible sites.
BIOGEOGRAPHY OF JACK PINE
Authors: Yeatman C. W.
Published: August 2008

Interpretation of genetic variation associated with geographic origin must take into account the evolution and migratory history of the species being-studied. A literature survey was made to determine the probable origin of jack pine (pinus banksiana) and its migration from glacial refugia following the Wisconsin glacial maximum. Jack pine and contorta pine (Pinus contorta) became differentiated following cooling of the climate and crustal uplift in western North America in the late Tertiary. Modern hybrid swarms and introgression of jack pine and lodgepole pine (Pinus contorta var. lalifolia) east of the Rocky Mountains are of recent origin, dating from late post-glacial migration from the east and west respectively. Geological and paleobotanical evidence, particularly from fossil pollen depositions, indicate that jack pine survived glaciation in an extensive refugium centered on the Appalachian Highlands of eastern North America, and not in additional refugia south or west of the Great Lakes. This conclusion is consistent with the clinal pattern of geographic variation evident from genecological studies of the species.
ON THE EXTRACTION OF PEROXIDASE ISOZYMES FROM BEAN LEAVES
Authors: Adatthody Kumaran Kozhikot , Racusen David
Published: August 2008

Conditions for the extraction of peroxidase from bean leaves were studied. Both the pH and the ionic strength of the extraction medium played an important role in the recovery of certain peroxidase isozymes. It was found that a major portion of the cationic peroxidase in the leaf tissue was sorbed to naturally occurring insoluble polymers at low ionic strength and neutral pH. These polymers seemed to act as ion-exchangers from which the enzyme could be progressively eluted by increasing sodium chloride concentration.
ISOLATION, INCIDENCE, AND VIRULENCE OF ASCOCHYTA SPP. OF PEAS FROM THE SOIL
Authors: Wallen V. R. , Wong S. I. , Jeun Julie
Published: August 2008

Ascochyta pinodella, cause of footrot, and Ascochyta pinodes, cause of blight, of peas were isolated from field soil by heating the soil to 100 C for 12–15 h followed by plating the soil on a medium containing rose bengal and chlortetracycline. A. pinodella was present in most soils where peas were growing and also in some soils where peas had not been grown for 1 to 5 years. Soil cultures of A. pinodella were weakly virulent but by host passage, re-isolated cultures produced typical symptoms of footrot on young plants. A. pinodes was isolated less frequently from soil; however, cultures were strongly virulent and inoculated plants showed typical disease symptoms in 5 days. Although infected seed has been considered to be the main source of inoculum, the frequent isolation of A. pinodes and A. pinodella from soil demands a re-appraisal of the epidemiology of this disease complex.
Inheritance of minor reaction gene combinations in wheat to Puccinia striiformis at two temperature profiles
Authors: Lewellen R. T. , Sharp E. L.
Published: August 2008

The inheritance of resistance of Rego and P. I. 178383 wheat varieties to a specific pathogenic type of Puccinia striiformis, stripe rust, was investigated at two temperature profiles, 2 C night / 18 C day and 15 C night / 24 C day. Mean infection type on Rego was a 0 at 2/18 and a 3− at 15/24. Two complementary dominant genes conferred about a 3− reaction at both profiles. In addition, one or more recessive temperature-sensitive genes contributed to the greater level of resistance of Rego at the lower temperature profile. P. I.178383 has one major gene conditioning rust resistance and an undetermined number of minor genes that express greater resistance at 15/24 than at 2/18. In combination with the Rego factors, there is an additive interaction at both temperature profiles for greater resistance.
Anatomy of Culcita macrocarpa
Authors: Sen U.
Published: August 2008

The anatomy of Culcita macrocarpa Presl., the taxonomic position of which has been in dispute, is described in detail for the first time. The stem is solenostelic. Important diagnostic features are the presence of cubical cells with silica crystals in both cortex and pith, and a transverse orientation of some of the sieve cells. Each petiole has a U-shaped vascular bundle. Stomata are of the syndetocheilic type with one subsidiary cell. The indusium has abaxial and adaxial lips which are structurally dissimilar. Anatomical characteristics of the species justify its inclusion in the Cyatheaceae (sensu Holttum and Sen, 1961), and show close relationship with Thyrsopteris.
The effect of rust infection on DNA, RNA, and protein in nuclei of Khapli wheat leaves
Authors: Bhattacharya P. K. , Shaw Michael
Published: August 2008

The effects were determined of infection with Race 15B of the stem rust fungus on the levels of nuclear DNA (Feulgen), RNA (azure B), histone (fast green pH 8.1), and total protein (fast green pH 2.0) and on the size of the nuclei in the mesophyll cells of the primary leaf of Khapli wheat (rust reaction type 1). Nuclear size, RNA, and total protein content increased and histone content decreased by 3 days after inoculation. DNA content decreased from 4 days after inoculation. These results for the resistant variety Khapli are similar to those reported earlier for the susceptible variety, Little Club, but the observed changes occur more rapidly after inoculation than they do in Little Club.
Tomato bushy stunt virus from Prunus avium. II. Serological typing and the characterization of antibody types and activities
Authors: Allen Wayne R.
Published: August 2008

Serological comparisons between the type strain of tomato bushy stunt virus and a strain from sweet cherry demonstrated that the degree of relationship was highly dependent upon the time of bleeding during the primary response. Cross-reactivity decreased after injection until just before the maximum titer was reached, and then gradually increased until the maximum value was attained. The increase in cross-reactivity was due, mainly, to a decline in synthesis and (or) release of specific antibodies. Sera fractionation revealed specific and cross-reactive antibodies among both light and heavy globulins. The cross-reactivity of light antibodies increased from the time of injection, but it remained nearly constant for heavy antibodies. Immunoelectrophoresis associated the light and heavy antibodies with IgG and IgM globulins, respectively.
The mosses of Bathurst Island, N.W.T., Canada
Authors: Brassard Guy R. , Steere William C.
Published: August 2008

Eighty-two moss species are reported from Bathurst Island, in the Canadian High Arctic. Pterygoneurum arcticum is new to the bryoflora of Arctic Canada. Sixteen species were found in subfossil peats. The Bathurst Island moss flora is most similar to that of Prince Patrick Island.
Calcium localization in Hypomyces-infected squash hypocotyls and effect of calcium on pectate lyase activity and tissue maceration
Authors: Hancock J. G. , Stanghellini M. E.
Published: August 2008

Pectate lyase from squash plants infected with Hypomyces solani f. sp. cucurbitae is dependent upon Ca for activity. As the Ca level is increased in reaction mixtures, the rate of degradation of pectate is increased. However, when the uronic acid/Ca ratio is [Formula: see text], enzymatic breakdown of pectate is inhibited. Pectate lyase activity is affected similarly when the pectate substrate is in a semisolid agar medium. Moreover, maceration of potato tissues is stimulated by a low exogenous supply of Ca but inhibited as the level is increased.Calcium is present in higher concentrations in lesions than adjacent healthy tissues, and autoradiography indicated that 45Ca accumulated in cell walls and middle lamellae in infected areas. However, calcium accumulation around lesions apparently does not greatly influence the rate of maceration by pectate lyase.
Metabolism of glucose-14C, pyruvate-14C, and mannitol-14C by Melampsora lini. I. Uptake
Authors: Williams P. G. , Shaw Michael
Published: August 2008

Aerial mycelium of the flax rust fungus (Melampsora lini (Pers.) Lév.) was grown on infected flax cotyledons in tissue culture. The endogenous respiration of detached mycelium varied from 1.5 to 4.8 μl/h per milligram dry weight, with a mean value of 2.6 ± 1.0. There was a significant negative correlation between respiration rate and percentage dry weight (r = −0.832; P < 0.025). The respiration of mycelium stored for longer than 10 h after excision was stimulated by the addition of glucose; such stimulation was not obtained consistently with freshly collected mycelium.The production of 14CO2 and the disappearance of radioactivity from the medium were measured at intervals during incubation of mycelium with glucose-1- and -6-14C, sodium pyruvate-1-, -2-, and -3-14C and mannitol-1-6-14C. Evidence was obtained that glucose is oxidized in the Embden–Meyerhof and pentose phosphate pathways and that pyruvate is oxidized via acetyl CoA and the tricarboxylic acid cycle. Rapid utilization of pyruvate- and mannitol-14C was preceded by a lag period of 4 to 9 h. The results are discussed in relation to the suitability of aerial mycelium for the study of rust metabolism.
Pigments of the genus Beauveria
Authors: Basyouni Sohair H. El , Brewer D. , Vining L. C.
Published: August 2008

Red coloring substances found in isolates of the imperfect fungus Beauveria were identified as the dibenzoquinone pigment oosporein. Yellow pigments were isolated from both B. bassiana and B. tenella cultures and found to be mixtures of similar compounds. Two types (designated tenellins and bassianins) occurred. Their distribution did not follow species lines. In cultures of a B. tenella isolate which produced both red and yellow pigments the optimum yield of oosporein was obtained with a glycerol–nitrate–salts medium and was unaffected by excess nitrogen source. Zinc ions stimulated and manganese ions depressed production. The optimum yield of bassianins occurred on a glucose – ammonium tartrate – salts medium with a high carbon:nitrogen ratio. Phosphate, above minimum requirements for growth, did not strongly influence the yield of either pigment. On a medium in which both oosporein and bassianins were produced, oosporein was formed first. Bassianins were accumulated rapidly only after depletion of the nitrogen source.
Some fungal parasites of Scrophulariaceae
Authors: Savile D. B. O.
Published: August 2008

Ramularia lewisii Savile sp. nov. on Mimulus lewisii in British Columbia, and Puccinia bhutanensis Savile sp. nov. on Pedicularis ? kingii in Bhutan, are described. Peronospora pedicularis, Melasmia mougeotii,Isariopsis veronicae (Pass.) Savile comb. nov., Ramularia bartsiae, and Schroeteria delastrina are newly reported in North America and Puccinia pedicularis in Canada. A small-spored Cylindrosporella, suspected to be the microconidial state of Guignardia veronicae, is newly reported from north-west North America. Host and range extensions are recorded for Peronospora grisea, Sphaerotheca fuliginea, Mycosphaerella pedicularis, Diplodina pedicularidis, Ramularia nivosa, Ramularia variabilis, Cronartium coleosporioides, Entyloma clintonianum, and E. linariae.
The inheritance of spore wall characteristics in Ustilago avenae and U. kolleri
Authors: Nielsen J.
Published: August 2008

Echinulation in Ustilago avenae is governed by complementarity of two dominant, indepèndently segregating genes. The gene for spore color, when homozygous recessive (buff spore wall), is epistatic to those for echinulation.
Pathogenic variability and the unit representing a single fertilization in Puccinia coronata var. avenae
Authors: Dinoor A. , Khair J. , Fleischmann G.
Published: August 2008

Single aeciospore analysis of progeny from both naturally and artificially fertilized crown rust pycnia support the conclusion that multiple fertilization may occur within a single protoaecial cup. Use of single aeciospore cultures afforded a higher level of purity of isolates than had previously been obtainable. Hybridization and genetic recombination can result in the production of many crown rust biotypes which differ pathogenically from each other.
A comparison of growth responses of Douglas fir and Sitka spruce to different nitrogen, phosphorus, and potassium levels in sand culture
Authors: Driessche R. van den
Published: August 2008

Douglas fir and Sitka spruce seedlings were grown in sand culture under controlled mineral nutrient conditions. Nitrogen, phosphorus, and potassium supply levels were varied one nutrient at a time in three separate experiments. The relative growth rate (RGR) of Sitka spruce was found to be higher than that of Douglas fir at high levels of N and K supply, although in all treatments the total dry matter production of Douglas fir was greater than that of Sitka spruce after 95 days. At low levels of P supply the RGR of Douglas fir was greater than that of Sitka spruce.Effects of treatment on RGR were apparently achieved mainly by their effect on net assimilation rate, but leaf weight ratio also showed a small, and significant, response to treatment.
The occurrence and pathogenicity of forms of Godronia cassandrae in Quebec
Authors: Smerlis E.
Published: August 2008

Three forms of Godronia cassandrae Peck, f. cassandrae, f. betulicola Groves, and f. vaccinii Groves, are reported from Quebec. Pathogenicity is demonstrated for all three forms. Neither f. cassandrae nor f. betulicola are host-specific at the generic level but occur on plants of several or different genera.
Mineral requirements for the growth of Anabaena spiroides in vitro
Authors: Volk Sherry L. , Phinney Harry K.
Published: August 2008

Anabaena spiroides Klebahn, isolated from Upper Klamath Lake, Klamath County, Oregon, was cultured in Gerloff's modification of Chu's number 10 medium. Preliminary to a study of the major nutrient mineral requirements, the initial culture medium was modified by elimination of sodium silicate, the addition of Tris(hydroxymethyl)aminomethane, and the substitution of hydrogen ferric ethylenediamine di-o-hydroxyphenylacetate (EDDHA) for ferric citrate – citric acid.Provision of mineral nitrogen in the medium was found unnecessary for growth, strongly suggesting that A. spiroides can fix nitrogen, but final proof awaits the development of bacteria-free cultures. Although phosphorus was required in relatively high concentrations to obtain maximum growth, it was apparently accumulated in the cells, allowing them to survive long exposure in phosphorus-deficient media. Several other major elements either were required in very minute amounts or were accumulated by the alga. Iron provided in the alkaline-stable chelate EDDHA was required in lower concentration than in Gerloff's medium. A definite, high requirement for calcium was found.A balanced medium was developed that supported an increase of 100% in dry weight, 23% in chlorophyll content, and 10% in organic nitrogen above that obtained in the initial medium.
A systematic and genecological study of Picea glauca and P. engelmannii, using paper chromatograms of needle extracts
Authors: La Roi George H. , Dugle Janet R.
Published: August 2008

This paper describes some applications of Picea needle extract chromatography to the interspecific relations of P. engelmannii Parry and P. glauca (Moench) Voss, and the intraspecific relations of P. glauca. Sixty-eight branch and cone collections of Engelmann, intermediate, and white spruce were used to obtain 57 morphologically indexed and 68 chromatographed specimens. Morphological Index was significantly correlated with collection site elevation. Nine of 28 unidentified needle extract substances exhibited definite geographic patterns of occurrence in specimens. Eight substances were significantly correlated with elevation. Ten substances occurred much more frequently in one or two of the three Morphological Index groups; their combined diagnostic value was high. Sixteen substances showed positive correlation in a Chi-square association network. A dependency network described the contingent occurrence of substances. Spruce collections were objectively classified into seven "Normal Association-Analysis" (NAA) groups which showed strong correlation with geography, elevation, Morphological Index, and spot diversity. A three-dimensional ordination of specimens was constructed on needle extract criteria; substances, elevations, indices, and spot diversity exhibited definite patterns and gradients on it; and the structural relations of the NAA groups were clarified. Final evaluation of chromatographic evidence for continuous intergradation of Engelmann and white spruce, and for ecotypic differentiation in white spruce awaits future research on the influence of environmental factors on the presence and absence of substances.
The identification of poplar mosaic virus in Canada
Authors: Navrátil S. , Boyer M. G.
Published: August 2008

An important disease of poplar in Europe caused by the poplar mosaic virus is reported as occurring on Poplar deltoides ssp. angulata in Canada. In all characteristics studied the virus appears identical with the European form.
Altered polyphenol metabolism in the foliage of Pinus sylvestris associated with European pine sawfly attack
Authors: Thielges Bart A.
Published: August 2008

Modified polyphenol metabolism in Pinus sylvestris was correlated with European pine sawfly attack. The unknown compound was not restricted to damaged tissue, indicating a more general response to injury.
A rapid method of sectioning dried coniferous needles for mycological studies
Authors: Farris S. H.
Published: August 2008

A method is described whereby thin sections of dry herbarium coniferous needles may be cut on a cryostat microtome. Stained, temporary slides suitable for diagnostic and (or) photomicrography purposes may be made in [Formula: see text] hours. Permanent slides may also be made by this method.
Type studies of Pleospora calvescens, Pleospova papaveracea, and some allied species
Authors: Shoemaker R. A.
Published: August 2008

The type of Pleospora pellita (Fr.) Rab. proved to be a Nodulosphaeria,N. robusta (Fr.) n. comb. Pleospora papaveracea (De Not.) Sacc. and its conidial state Dendryphion penicillatum (Corda) Fr. are redescribed from their respective types, natural collections, and cultures, and contrasted with the similar but distinct hyphomycete, Pseudostemphylium chlamydosporum Hoes, Bruehl & Shaw. Pleospora calvescens (Fr.) Sacc. and its conidial state Microdiplodia henningsii Staritz are illustrated from the type of P. calvescens. Study of types of names of some Pleospora species resulted in the following additional synonymies: P. papaveracea (=P. pellita var. bardanae (Niessl) Wehm.), P. scirrhioides Sacc. (=P. pellita var. oligostachyae (Ell. & Ev.) Wehm.), P. thuemeniana Sacc. (=P. cereicola Speg.), P. chamaeropis (Dur. & Mont.) Sacc. (=P. opuntiicola Bub.), P. betae Newod. (=P. bjoerlingii Byford ≡ P. betae Björling).
Diploospora
Authors: Hughes S. J.
Published: August 2008

Diploospora rosea Grove, the type species of Diploospora Grove, is illustrated and redescribed from the type collection.
Observations on the occurrence of sporophytic characters in the gametophytes of Adiantum lunulatum
Authors: Sawhney V. K.
Published: August 2008

In some of the gametophytes of the obligate apomict fern A. lunulatum, grown under artificial conditions, we observed patches of tissue which contained cells morphologically similar to the epidermis of the sporophytic leaf. There seems to be an imperceptible transition from gametophytic cell types with entire walls to sporophytic cell types with wavy margins. Stomata are frequently observed among these cells.The observations seem to favor the 'homologous theory' of alternation of generations.
Studies in the Alismataceae. I. Developmental morphology of Echinodorus tenellus
Authors: Charlton W. A.
Published: August 2008

Development of each shoot of Echinodorus tenellus proceeds through a vegetative phase when foliage leaves are formed and enters an abruptly initiated reproductive phase, when only scale leaves are formed, by conversion of the meristem into a different form, while a large and precocious bud in the axil of the last foliage leaf continues vegetative development. The reproductive meristem may, according to conditions, form an inflorescence or a “pseudostolon” with vegetative axillary buds in place of flowers. Both inflorescence and pseudostolon show a regular sequence of long and short internodes and a regular alternation of scale leaves with and without axillary buds, though the pattern of the inflorescence is less regular than that of the pseudostolon and the inflorescence has a terminal flower while the pseudostolon has unlimited growth. Phyllotaxis varies according to the stage of development of the plant and in the reproductive shoot is largely determined by the patterns of internode elongation and bud distribution. The significance of the developmental pattern is discussed.
The variation of carbohydrates in various species of grasses and legumes
Authors: Ojima Kunihiko , Isawa Takeshi
Published: August 2008

Qualitative and quantitative determinations were made of the available carbohydrates and the component sugars of hemicellulose in the aerial parts of a number of species of grasses and legumes cultured in the northern area of Japan. Plant materials used were leaf sheaths and stems from 25 species of grasses in the heading stage, and of 5 species of legumes at the flowering stage. The plants were found to vary in the type of storage carbohydrate contained in the aerial parts. Some species contained fructosan and sucrose, others starch and sucrose, while a few species contained very little fructosan or starch but mainly sucrose. The fructosan-storing species are members of the subfamily Festucoidea which are native to temperate or cooler climates. The species classified under subfamilies Eragrostoidea, Panicoidea, and Bambsoidea which are native to warmer climates, accumulated starch rather than fructosan. The hemicelluloses of southern grasses also contained a higher proportion of glucose relative to xylose than those of the northern grasses or subfamily Festucoidea. The plants were classified into groups according to differences in the type and relative proportion of individual carbohydrates and the results are discussed from a taxonomic point of view.
Developmental studies on leafy spurge (Euphorbia esula). Apices of seedling and adventitious shoots
Authors: Raju M. V. S.
Published: August 2008

The apex of leafy spurge (Euphorbia esula L.) has a stratified mantle and a subjacent core. The mantle of seedling shoots had two to four layers and that of the adventitious shoots developed on roots had three to eight layers. Results obtained from an analysis of the mantle carried out with reference to the mitotic activity indicated a greater frequency of divisions in the peripheral parts where the leaf primordia are initiated than in the middle part of the apex. The adventitious shoots that are normally determinate in their growth potentiality develop an extensive layering in their apices. The shoot apices of the seedlings, which have a more prolonged growth, show much less stratification than those of the adventitious shoots.
Changes in moisture content and color of the cambial zone in bolts of pine stemwood during colonization by Fomes annosus
Authors: Thompson J. H. , Cowling E. B. , Ross E. W.
Published: August 2008

Two isolates of Fomes annosus were found to grow with equal rapidity (about 12 mm per day at 24 C) through, or over, a split surface of fresh sapwood in bolts cut from pine stems, and at a similar rate over the surface of malt-extract agar. Since growth through wood was not substantially slower than growth over a similar but obstacle-free surface, penetration of cell walls by formation of boreholes or penetration of pit pairs evidently is a rapid process.As the fungus progressed through the bolts longitudinally, marked browning of the cambial zone was observed at whatever distance from the inoculated end of the bolts the fungus could be isolated. Also, as much as 13% of the water present was moved from infected portions of inoculated bolts to portions not yet colonized by the fungus. No satisfactory explanation for the observed movement of water was discovered although several hypotheses were considered or tested.
Amino acids as nitrogen sources for conidial production of Venturia inaequalis
Authors: Ross R. G.
Published: August 2008

Nineteen amino acids were compared in synthetic culture media as nitrogen sources for conidial production by isolates 1096 and 365-4 of Venturia inaequalis (Cke.) Wint. and 10 were rated with isolate K-100. With isolate 1096 only L-histidine supported appreciable conidia production and with 365-4 it was an excellent source of nitrogen for sporulation. Sporulation by isolates 365-4 and K-100 was generally excellent with DL-(α)-alanine and fair with DL-(β)-phenylalanine and DL-asparagine. DL-(α)-aminobutyric acid, L-proline, and glycine were good nitrogen sources for isolate 365-4. Few or no conidia were produced with the amino acids DL-aspartic, DL-glutamic, DL-glutamine, DL-methionine, DL-threonine, or DL-leucine.Maximum sporulation occurred as soon as good mycelial growth was established but amino acids suitable for growth were not necessarily good nitrogen sources for sporulation.
Etiological studies on needle fungi associated with semimature-tissue needle blight of eastern white pine
Authors: Linzon S. N.
Published: August 2008

The results of etiological studies on semimature-tissue needle blight (SNB) of eastern white pine (Pinus strobus L.) deny any role to needle fungi as the primary cause. No mycelium was found in newly blighted semimature tissue by either cultural or histological methods. Mycelia of several saprophytic fungi were isolated from the blighted portions of current year needles about 2 weeks after the onset of SNB, and fruit-bodies of different organisms were found to occur both in the interior and on the exterior of blighted needles about 4 weeks after the first occurrence of disease symptoms. The fruit-bodies of two Ascomycetes, Cenangium acuum Peck & Cooke and Hypoderma desmazierii Duby (= Lophodermium brachysporum (Rostrup) Tub.), were found on the necrotic terminals of attached 1-year-old needles which had been blighted in the previous year. The morphological development of apothecia of C. acuum was studied. Hysterothecia of Lophodermium spp. (L. pinastri (Schrad. ex Fr.) Chev. and L. nitens Darker) occurred ubiquitously on fallen white pine needles. Aerial spore trapping snowed that ascospores of C. acuum were abundant, those of Lophodermium spp. were prevalent, and those of H. desmazierii were practically non-existent in the area investigated. There was little coincidence between the occurrence of SNB outbreaks and peak populations of air-borne ascospores of these fungi. Ascospore suspensions and needles bearing fructifications of C. acuum and Lophodermium spp. were used to inoculate the newly developing needles of SNB-susceptible and non-susceptible field trees and potted seedlings, but the typical symptoms of SNB did not develop as a result of these inoculations. Two fungicides, captan and Bordeaux mixture, were applied to SNB-susceptible and non-susceptible field trees throughout the growing season, but neither fungicide prevented the symptoms of SNB from appearing on the new needles of susceptible trees at the same time as they appeared on untreated susceptible trees in the area. The fungicidal sprays, however, did prevent saprophytic fungi from invading blighted portions of the needles. It is concluded from this investigation that SNB is not a disease of fungal origin.
Towards a mathematical model of limestone pavement vegetation. I. Vegetation and microtopography
Authors: Yarranton G. A. , Beasleigh W. J.
Published: August 2008

A model for the determination of the probability of occurrence of a species at a specified point is defined as: P = B0 + B1X1 + B11X12 + B111X13 … + B2X2 + B22X22 + B222X23 ….Limestone pavement was chosen to experiment with such models because of the relatively small number of evidently significant environmental variables. Species frequency data for 60 sites, classified in a block design involving microtopography, are presented. All sites were located in grikes, elongated fissures in the limestone with depths far exceeding their widths. Analyses of variance for 31 species show significant effects of width, depth, and aspect of grikes and of interactions between them, on the frequencies of most species. The matrix of between-species correlation coefficients suggests a continuous range of variation in distribution and presumably environmental response, of the species. Examination of the relationship between microclimatic and topographic variables is required before independent variables for incorporation into the model are selected.
Tolerance and Resistance to Cadmium in White Suckers (Catostomus commersoni) Previously Exposed to Cadmium, Mercury, Zinc, or Selenium
Authors: Duncan D. A. , Klaverkamp J. F.
Published: August 2008

White suckers' (Catostomus commersoni) tolerance of and resistance to Cd is increased as a consequence of previous metal exposure. The order of metal toxicity to white suckers was Hg > Cd > Zn >> Se. Toxicity curves clearly showed that white suckers exposed to sufficiently elevated Cd, Hg, or Zn levels subsequently survived longer than control suckers in Cd toxicity tests. The 96-h Cd LC50 increased by 61 or 127% following 1 wk exposure to.0.40 or 0.72, respectively, of the 96-h Cd LC50 (1.11 mg Cd/L) for control suckers. The 96-h Cd LC50 also increased by 260% following 1 wk exposure to 0.32 of the 96-h Hg LC50 (0.687 mg Hg/L). The 12- and 24-h Cd LC50 values were increased, but the 48-, 72-, and 96-h values were not, following 1 wk exposure to elevated Zn levels. Exposure to Se prior to toxicity testing had little or no effect on Cd toxicity. Mechanisms which might be responsible for the decreased Cd toxicity include decreased uptake, increased excretion, redistribution of metals to less-sensitive target sites, and/or induced synthesis of metallothionein. Possible consequences of increased tolerance to metals include compensatory adjustments which result in poor recruitment into the population, accumulation of potentially toxic metals, and increased survival in metal-impacted areas.Key words: tolerance, resistance, acclimation, cadmium, mercury, zinc, selenium, white sucker, Catostomus commersoni, toxicity
Simulation of Temperature and Upwelling Effects on the English Sole (Parophrys vetulus) Spawning Season
Authors: Kruse Gordon H. , Tyler Albert V.
Published: August 2008

Spawning times for English sole (Parophrys vetulus) in Oregon waters were estimated for 13 yr using data on adult female gonadal condition, and surveys of pelagic larvae and benthic juveniles of known ages. The spawning season for this species is extremely protracted and variable. Some spawning may occur in all months, but most occurs between September and April, with a peak lasting 1–3 mo within this period. Variations in the English sole spawning season appear to be largely accountable by variations in a continental shelf temperature index (developed from a relationship with Neah Bay sea level). The following three hypotheses about temperature control of spawning were described by mathematical relationships which were incorporated into a simulation model that was driven by the time series of the bottom temperature index: (1) the rate of gonadal development is inversely related to summer bottom temperatures; (2) spawning is inhibited by temperatures below about 7.8 °C; and (3) spawning is delayed by rapid increases in bottom temperature. The model in its present form can be used to simulate spawning activity for years void of empirical spawning records and to design laboratory experiments capable of validating cause-and-effect relationships.Key words: Oregon, English sole, spawning time, upwelling, shelf temperature, hypotheses, simulation model
Ammonia-Caused Gill Damage in Channel Catfish (Ictalurus punctatus): Confounding Effects of Residual Chlorine
Authors: Mitchell Stephen J. , Cech Jr. Joseph J.
Published: August 2008

Histological evidence failed to confirm that ammonia is a direct causative agent of gill hyperplasia, as previously believed, in channel catfish, Ictalurus punctatus. Levels of residual chlorine compounds, which are typical of charcoal-filtered municipal water or chlorinated sewage effluent, together with moderate ammonia levels caused severe gill hyperplasia. These results both question the validity of attributing gill tissue hyperplasia to ammonia alone by past investigations and emphasize the serious problem of obtaining contaminant-free water for aquatic toxicological studies.Key words: Ictalurus punctatus, channel catfish; ammonia, gills, chloramine, hyperplasia, water quality
Seasonal Variation in Weight-Specific Growth Rates, Feeding Rates, and Growth Efficiencies in Microgadus tomcod
Authors: Salinas I. M. , McLaren I. A.
Published: August 2008

Among Microgadus tomcod from Cumberland Basin, Bay of Fundy, exponents of the weight–length relationship (liver, gonads removed) ranged from 2.74 in April, after spawning, to 3.47 in September, after summer feeding. This implies that growth rate per unit of weight is seasonally higher in larger fish, although this diminishes on an annual basis after 2 yr in these short-lived (< 4 yr) fish. In feeding experiments larger fish after spawning increased feeding (weight-specific ration declined with weight in September, not in April-May) and grew faster, using proportionately more food for growth (growth efficiency not correlated with weight in September, positively so in April–May).
The English–Wabigoon River System: III. Selenium in Lake Enclosures: Its Geochemistry, Bioaccumulation, and Ability to Reduce Mercury Bioaccumulation
Authors: Turner Michael A. , Rudd John W. M.
Published: August 2008

Aquatic biota have been shown previously to bioaccumulate selenium rapidly with a concomitant reduction in accumulation of mercury when exposed to 100 μg Se/L. Using radioisotope techniques this experiment extends these observations by examining the effects of single additions of sodium selenite at 1, 10, and 100 μg Se/L to experimental ecosystems (130 m3) located in mercury-contaminated Clay Lake, northwestern Ontario (50°03′N, 90°30′W). The major sink for added selenium and mercury was the sediment. Movement of 75Se into the sediments in control enclosures (< 0.2 μg Se/L) appeared to stabilize within 6 wk; however, movement did not stabilize in the selenium enclosures where selenium remaining in water was largely ionic. At first, selenium accumulated rapidly in net plankton but then declined in correspondence with water concentrations. In Anadonta sp. and Orconectes virilis, selenium increased with time and in proportion to ambient selenium. Stable concentrations of selenium were not achieved in fish after 2 mo, but levels always varied according to the following sequence: Semotilus margarita < Perca flavescens < Catostomus commersoni, ranging from 0.2 to 0.4 μg Se/g (wet wt) at 1 μg Se/L. Accumulation of mercury was reduced in several biota in a concentration-dependent manner, with greatest reductions observed at 100 μg Se/L. These reductions appeared to depend on the position of the organism in the food web. In fish, the reduction was proportional to the amount of selenium accumulated. If not present in excessive amounts, selenium might be of benefit in the treatment of aquatic ecosystems with either atmospheric or point-source mercury pollution problems.
Size-Biased Survival in Steelhead Trout (Oncorhynchus mykiss): Back-Calculated Lengths from Adults' Scales Compared to Migrating Smolts at the Keogh River, British Columbia
Authors: Ward B. R. , Slaney P. A. , Facchin A. R. , Land R. W.
Published: August 2008

Lengths of wild, winter-run steelhead smolts, estimated by back-calculation procedures from adults' scales, were compared with observed lengths of migrating smolts sampled near the mouth of the Keogh River, Vancouver Island. Size-biased smolt-to-adult survival rates were estimated for several length categories by utilizing length frequencies from observed smolts, smolt length frequencies which were back calculated from adults' scales, smolt yield, and adult returns. Back-calculated smolt length (BSL) of adults returning from smolts of 1977 to 1982 averaged 193 mm compared to 176 mm for observed smolt length (OSL). Mean BSL was larger than OSL in every year. Adults from odd-numbered smolt years had larger BSL than adults from even-numbered smolt years similar to the pattern in OSL. BSL increased with increased years spent in salt water, based on ageing adults' scales. Males and females had different BSL based on number of years spent in fresh water and salt water, although they exhibited the same mean BSL overall. The smolt-to-adult survival estimates were in close agreement with previous estimates derived from the mean OSL. Predictability of survival in the ocean based on the length of smolts was extended over a broad range of the length distribution of wild steelhead smolts.
A Genetic Comparison of Sympatric Populations of Sand Lance (Genus Ammodytes) from the Region East of Cape Soya, Japan
Authors: Okamoto Hiroaki
Published: August 2008

Sand fance (Genus Ammodytes) collected from four stations off Japan and one station at Kodiak, Alaska were genetically characterized at 17 protein coding loci using starch-gel electrophoresis. Sand lance in Wakkanai (Cape Soya, Japan) consist of two genetically distinct groups. They are fixed for different alleles at four loci (Ldh-2, -3, G3pdh-2, and Mdhp-2). The genetic structure of one of the groups (Wakkanai-a group, W-a) is similar to that of A. personatus around Japan. The other group (Wakkanai-b group, W-b) has different genetic structure from either A. personatus or the Alaskan collection, which is presumed to belong to A. hexapterus. It is not presently possible to identify the affiliation of the W-b group; however, despite its sympatry with the W-a group, it is reproductively isolated and therefore is probably a distinct species occurring northeast of Hokkaido.
Absorption of Ascorbic Acid and Ascorbic Sulfate and their Interaction with Minerals in the Digestive Tract of Rainbow Trout (Oncorhynchus mykiss)
Authors: Dabrowski K. , Köck G.
Published: August 2008

The sites of absorption of ascorbic acid (AA) in the rainbow trout (Oncorhynchus mykiss) gut were located in the stomach (20.7%), pyloric caecae region (23.4%), middle intestine (21.9%) and posterior intestine (20.1%). Ascorbic sulfate (AS) were found to be absorbed in the stomach (27.7%) although it is likely that the figure obtained is an overestimate. This conclusion is based on the concentration factor of the intestinal contents (faeces/food ratio) being much higher for ascorbic sulfate than for an external dietary marker, chromic oxide. The apparent protein absorption rates from the three diets used were not significantly different (P < 0.01), ranging from 86.9 to 91.5%. Three subsequent samplings, one week apart, did not reveal changes in AA or AS absorption in trout, suggesting that fish were neither "saturated" with AA nor had they developed the means to utilize the dietary AS. In most cases, the mineral contents in faeces were similar for all diets, although the concentration factors (faeces/food level), varied greatly during the course of the trial (1.9–7.1 for Zn, 1.8–4.9 for Fe, and 2.4–3.7 for Cu). The concentrations of Fe and Zn in the contents of the posterior intestine were lower in the fish fed an AA-supplemented diet than in fish fed on AS and deficient diets, which may suggest an increased absorption of these elements.
Jet propulsion of Nautilus: a surviving example of early Paleozoic cephalopod locomotor design
Authors: Chamberlain Jr. John A.
Published: August 2008

Like its coleoid relatives, Nautilus swims by jet propulsion. However, in the structure and functioning of its motor, Nautilus differs markedly from its contemporaries. Compared with that of squids, Nautilus locomotion is based on small propellant volume, low mantle cavity pressure, low propellant velocity, and small propulsive muscle mass. Propulsive performance of Nautilus is consequently unspectacular, with as little as one-eighth the thrust and one-tenth the burst speed observed in squids of equivalent size. Nautilus survives as a result of its slow-moving, vertically mobile, foraging life-style limited to habitats where competition with fast-moving, agile swimmers is minimal. Fossil cephalopods faced similar design constraints, which may have contributed to their decline, but nonbiologic factors such as sea level fluctuations may also have been important in directing the course of cephalopod evolution.
Neurally-derived nitric oxide regulates vascular tone in pulmonary and cutaneous arteries of the toad,Bufo marinus
Authors: Jennings Brett L. , Donald John A.
Published: August 2008

In this study, the role of nitric oxide (NO) in regulation of the pulmocutaneous vasculature of the toad, Bufo marinus was investigated. In vitro myography demonstrated the presence of a neural NO signaling mechanism in both arteries. Vasodilation induced by nicotine was inhibited by the soluble guanylyl cyclase (GC) inhibitor, 1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one, and the NO synthase (NOS) inhibitor, Nω-nitro-l-arginine (l-NNA). Removal of the endothelium had no significant effect on the vasodilation. Furthermore, pretreatment with N5-(1-imino-3-butenyl)-l-ornithine (vinyl-l-NIO), a more specific inhibitor of neural NOS, caused a significant decrease in the nicotine-induced dilation. In the pulmonary artery only, a combination of l-NNA and the calcitonin gene-related peptide (CGRP) receptor antagonist, CGRP(8-37), completely blocked the nicotine-induced dilation. In both arteries, the vasodilation was also significantly decreased by glibenclamide, an ATP-sensitive K+(K+ATP) channel inhibitor. Levcromakalim, a K+ATPchannel opener, caused a dilation that was blocked by glibenclamide in both arteries. In the pulmonary artery, NO donor-mediated dilation was significantly decreased by pretreatment with glibenclamide. The physiological data were supported by NADPH-diaphorase histochemistry and immunohistochemistry, which demonstrated NOS in perivascular nerve fibers but not the endothelium of the arteries. These results indicate that the pulmonary and cutaneous arteries of B. marinus are regulated by NO from nitrergic nerves rather than NO released from the endothelium. The nitrergic vasodilation in the arteries appears to be caused, in part, via activation of K+ATPchannels. Thus, NO could play an important role in determining pulmocutaneous blood flow and the magnitude of cardiac shunting.