Phytoplankton population dynamics of a small reservoir: effect of intermittent mixing on phytoplankton succession and the growth of blue-green algae

The seasonal succession of the phytoplankton of a small reservoir(Guelph Lake, Ontario) in the spring-summer of 1982 was comparedto that in 1981. Mixing of the deeper waters occurred severaltimes throughout the summer in 1982 but not in 1981. The waterat 10 m became anoxic for only 2 weeks in late July in 1982.In contrast, in 1981, the water at 10 m became anoxic at thebeginning of July and remained so until mid-September. The phytoplanktondynamics observed in 1982 did not follow the typical progressionfrom spring diatoms to summer species adapted to survive understratified conditions, as in 1981. Diatoms were present throughoutthe summer in higher amounts in 1982 than in 1981. The mostobvious difference in the two summers was the much greater abundanceof Aphanizomenon flow-aquae in 1982. Other blue-green algaeincluding Microcystis aeruginosa, Gomphosphasria lacustris,and Lyngbya birgei appeared earlier on in 1982, but did notimmediately increase in abundance as in 1981. In 1982, ratesof phytoplankton community change were low in May and June andincreases were observed in mid-July, early August, late Augustand late September. In contrast, in 1981, the rate of communitychange increased in late May, mid-June, early July and lateJuly and remained low throughout August and September. ¹Present address: Department of Zoology, University of Alberta,Edmonton, Alberta T6G 2E1, Canada. ²Present address: CSIRO Division of Fisheries Research, G.P.O.Box 1538, Hobart, Tasmania 7001, Australia     

Phytoplankton population dynamics of a small reservoir: use of sedimentation traps to quantify the loss of diatoms and recruitment of summer bloom-forming blue-green algae

A vertical series of sedimentation traps was placed in a smallreservoir (Guelph Lake, Southern Ontario, Canada) in the springthrough summer of 1981 to intercept floating and sinking phytoplanktoncells. Information from the sedimentation traps was used todetermine the sinking loss rates of diatoms and to estimatethe relative contribution of sedimentation to the loss of thesespecies. Sinking loss rates varied with time and with depth.Sinking loss rates for Stephenodiscus astrea, Melosira granulata,and Asterionella formosa increased with the onset of thermalstratification. The abundance of Cyclotella meneghiniana declinedas the surface pH increased. The results showed good agreementbetween the proposed sedimentary fluxes of diatoms and the correspondingmaximum standing crop. Information from the trap catches wasalso used to examine the possibility of recruitment of summerblue-green species from the sediments. Specific migration ratesof floating colonies of Microcystis aeruginosa, Gompliosphaerialacustris and of Lyngbya Birgei filsments at 10 m were high(>1) for periods of time in August. For these blue-greenalgae, estimates of the population gain due to recruitment fromthe sediments ranged from 2 to 4% of the maximum standing crop.The high rates of accumulation of total phosphorus (TP) in thedownward facing trap at 10 m provided further evidence thatresuspension of material from the sediments occurred at thistime. The appearance of these blue-green algae cointided withhigh surface temperatures and the development of anoxic conditionsat 10 m. The growth or recruitment of Aphanizomenon flos-aquaewas initiated under different environmental conditions thanthose for Mierocystis, Gomphosphaeria and Lyngbya. Evidencesuggests that the Aphanizomenon filaments present at Station1 originated from the Station 3 end of the lake and were advectedtowards Station 1. ¹Present address: Zoology Department, University of Alberta,Edmonton, Alberta T6G 2E1, Canada. ²Present address: CSIRO Division of Fisheries Research, GPOBox 1538, Hobart, Tasmania, Australia 7001.     

Cytochemical Localization of Calcium and Ca2+-ATPase Activity in Plant Cells under Chilling Stress: a Comparative Study between the Chilling-Sensitive Maize and the Chilling-Insensitive Winter Wheat

Electron microscopic observations revealed that electron-denseantimonate Ca²⁺ deposits were mostly localized in the vacuoleand the intercellular space in both maize and winter wheat whentheir seedlings were grown at 25°C. The reaction products—ceriumphosphate deposits of Ca²⁺- ATPase activity were mainly seenat the cytoplasmic side of the plasma membrane. Few cerium phosphatedeposits also were observed on the nuclear envelope. In bothspecies, after 1 or 3 h 2°C chilling, antimonate Ca²⁺ depositsincreased in the cytosol and the nucleus, but cerium phosphatedeposits showed no visible difference compared to their corresponding25°C seedlings. After 12, 24, or 72 h chilling, maize seedlingsstill maintained a high level of antimonate Ca²⁺ deposits inthe cytosol and the nucleus. During these periods, maize Ca²⁺-ATPase,as indicated by the number of cerium phosphate deposits, becameless and less active as chilling proceeded. In winter wheat,the increased cytosolic and nuclear antimonate Ca²⁺ depositswere restored to a low resting level after 12, 24, or 72 h chilling,while the Ca²⁺-ATPase was maintained active, contrary to maizescenario. The transient cytosolic and nuclear Ca²⁺ increaseand the activities of Ca²⁺-ATPase during chilling are discussedin relation to plant chilling injury and cold acclimation. ³ Present address: Department of Agricultural, Food and NutritionalScience, University of Alberta, Edmonton, Canada T6G 2P5.     

A molecular,isozyme and morphological map of the barley (Hordeum vulgare) genome

A map of the barley genome consisting of 295 loci was constructed. These loci include 152 cDNA restriction fragment length polymorphism (RFLP), 114 genomic DNA RFLP, 14 random amplified polymorphic DNA (RAPD), five isozyme, two morphological, one disease resistance and seven specific amplicon polymorphism (SAP) markers. The RFLP-identified loci include 63 that were detected using cloned known function genes as probes. The map covers 1,250 centiMorgans (cM) with a 4.2 cM average distance between markers. The genetic lengths of the chromosomes range from 124 to 223 cM and are in approximate agreement with their physical lengths. The centromeres were localized to within a few markers on all of the barley chromosomes except chromosome 5. Telomeric regions were mapped for the short (plus) arms of chromosomes 1, 2 and 3 and the long (minus) arm of chromosomes 7.This research was also supported by other members of the NABGMP: K. Kasha, Department of Crop Science, University of Guelph, Guelph, Ontario, Canada NIG 2W1; W. Kim, Agriculture Canada Research Station, 195 Dafoe Road, Winnipeg, Manitoba, Canada R3T 2M9; A. Laroche, Agriculture Canada Research Station, P.O. Box 3000 Main, Lethbridge, Alberta, Canada,TU 4B1; S. Molnar, Plant Research Centre Agriculture Canada, Central Experimental farm, Ottawa, Ontario, Canada K1A 0C6; G. Scoles, Department of Crop Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N OWOThis research is part of the North American Barley Genome Mapping Project, R. A. Nilan and K. Kasha, Coordinator and Associate Coordinator, respectively Permanent address: Department of Plant Genetics, NI Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow     

γ-Aminobutyric acid (GABA) and other amino acids in tissues of the tick,Amblyomma hebraeum (Acari: Ixodidae) throughout the feeding and reproductive periods

We assayed a variety of tick (Amblyomma hebraeum Koch; Acari, Ixodidae) tissues for a number of amino acids throughout the feeding and early reproductive periods. Our HPLC assay could detect as little as 2–5 pmol per sample of the following: GABA, glycine, serine, glutamine, alanine, taurine, glutamate and aspartate. All of these amino acids could be detected in the salivary gland, synganglion (=total CNS in acarines), haemolymph, Gené's organ, seminal receptacle and ovary. GABA reached high levels in the salivary gland of freshly engorged ticks (685 nmol g^-1) and in the synganglion it exceeded 1000 nmol g^-1 throughout most of the feeding cycle and the first week post-engorgement. GABA also reached a peak titre in the haemolymph of 40 nmol ml^-1. Taurine levels peaked at 1065 nmol g^-1 in the salivary gland from large partially fed ticks. Glutamate and aspartate were likewise found in the salivary gland and synganglion at high concentrations. For most of the amino acids there is insufficient information to correlate these titres (and fluctuations of titres) to neuromodulatory functions. It is possible, however, that the high GABA titre in the salivary gland of engorged ticks is correlated with an augmented level of fluid secretion.Deceased: Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada, T6G 2E9.     

Folylpolyglutamate Derivatives of Pisum sativum L. Determination of Polyglutamate Chain Lengths by High Performance Liquid Chromatography Following Conversion to p-aminobenzoylpolyglutamates

The folypolyglutamate derivatives of pea seedlings (Pisum sativumL. cv. Homesteader) were extracted in the presence of 2-mercaptoethanoland cleaved to p-aminobenzoylpolyglutamates by treatment withZn-HCl. Azo dyes were formed by reaction with naphthylethylenediamine and purified by polyacrylamide gel chromatography. p-Aminobenzoylpolyglutamateswere regenerated from these dyes by Zn treatment and then concentratedin vacuo. These derivatives were separated according to glutamylchain length by high performance liquid chromatography on WhatmanPartisil SAX columns. The folylpolyglutamates of 4 day old peacotyledons, pea leaves and isolated chloroplasts were mainlytetra- and pentaglutamates. These and folates of shorter chainlength were labelled when seeds and aerial shoots were incubatedwith p-aminobenzoate-[¹⁴C]. Labelling of the pentaglutamatewas reduced in seeds that were imbibed in the presence of 0.1mM methotrexate. Studies of cotyledon folylpolyglutamate synthetaseshowed that polyglutamate chain length was affected by incubationtime and the concentration of tetra-hydrofolate monoglutamatein the reaction system. ¹Present address: Department of Biology, University of Lethbridge,Alberta, Canada T1K 3M4 ²Present address: Department of Horticulture, Xiong-yue AgriculturalCollege, Xiong-yue, Liaoning Province, China (Received August 4, 1989; Accepted December 5, 1989)     

Purification and characterization of uroporphyrinogen decarboxylase from tobacco leaves

1. Uroporphyrinogen decarboxylase which catalyzes the formationof coproporphyrinogen from uroporphyrinogen is located in thesoluble fraction of tobacco leaves and was purified 72 foldthrough ammonium sulphate precipitation and calcium phosphosphategel absorption. 2. Kinetic studies indicated that the apparentMichaelis constant was 1 ? 10^-6 M for uroporphyrinogen III (pH6.5; 37?C). Uroporphyrinogen III served as a much better substratethan uroporphyrinogen I under the standard conditions of thisstudy. 3. Enzyme activity was inhibited by thiol reagents andheavy divalent cations and was stimulated by some chelatingagents. 4. Both chloride and fluoride salts inhibited the formationof coproporphyrinogen from uroporphyrinogen. ¹Present address: Department of Chemistry, Simon Fraser University,Burnaby 2, British Columbia, Canada. ²Present address: Biology Department, Utah State University,Logan, Utah 84322, U. S. A. (Received June 8, 1974; )     

The utilization of aromatic compounds by yeasts

Yeasts belonging to 6 genera were isolated from sewage and tested for their ability to use 15 hydroxy derivatives of phenol and benzoic acid as carbon source. The majority were able to produce colonies on at least 10 of the simple monophenol derivatives tested. Salicylic acid,p-hydroxybenzoic acid and gentisic acid were the most commonly used benzoic acid derivatives and resorcinol and phloroglucinol the most frequently metabolized phenols. However, there was no obvious relationship between the utilization of these compounds and the generic classification of the yeasts.Summer student, 1967. Graduate Student, Department of Microbiology, University of Alberta, Edmonton, Alberta, Canada.The authors wish to acknowledge the capable assistance of Mrs. C. Knapp and Mr. N. R. Gardner.     

SOMATIC MITOSIS IN NEUROSPORA CRASSA

Ward , E. W. B., and K. W. Ciurysek . (Canada Department of Agriculture, Edmonton, Alberta.) Somatic mitosis in Neurospora crassa. Amer. Jour. Bot. 49(4): 393–399. Illus. 1962.—The process of nuclear division in the vegetative mycelium of Neurospora crassa was studied with the aid of the HCl-Giemsa staining technique. Division followed the conventional mitotic sequence and 7 morphologically distinct chromosomes were demonstrated at metaphase. The findings are discussed in relation to other proposed schemes of nuclear division in the fungi.     

Degradation of Xyloglucan by Wall-Bound Enzymes from Soybean Tissue II: Degradation of the Fragment Heptasaccharide from Xyloglucan and the Characteristic Action Pattern of the {alpha}-D-Xylosidase in the Enzyme System

Hydrolysis of the fragment heptasaccharide (glucose : xylose= 4 : 3) from xyloglucan with an enzyme preparation from soybeancell wall produced a penta- and a trisaccharide. The resultsof fragmentation analysis of these oligosaccharides with Aspergillusoryzae ß-D-glucosidase indicate the following structuresfor the penta- and trisaccharide. The detection of these intermediate products suggested thatdegradation of the heptasaccharide took place by sequentialsplitting of the -D-xylosidic and ß-D-glucosidic linkages.A characteristic action pattern of the a-D-xylosidase in theenzyme preparation was found. ¹Present address: Department of Biology, McGill University,Montreal, Canada. ²Present address: Department of Botany, Iowa State University,Ames, Iowa 50010, U.S.A. (Received August 20, 1982; Accepted December 7, 1982)     

Embryogenesis and plant regeneration of Medicago spp. in tissue culture

Ten cultivars and breeding lines from two species of alfalfa (Medicago media and M. sativa) were screened for their ability to produce embryos and plantlets from the root and hypocotyl under three different tissue culture protocols. The three protocols differed in basal salt composition, vitamins, hormones and cytokinin additions. That protocol having a high 2–4,D low cytokinin induction step gave the highest percentage of embryogenic calli in some cultivars and lines. M. media cultivars and breeding lines had a high percentage of embryoid formation. M. sativa cultivars gave no embryoid formation. Two M. media breeding lines (Br1 and Le1), which were intermediate in the percentage of embryogenic calli formed from explants, had the highest number of regenerated plants established in soil. The creeping rooted M. media cultivar Heinrichs produced the highest percentage of embryogenic calli from explants but most of these embryoids were abnormal and failed to grow in soil or vermiculite. Accordingly, successful regeneration is directly related to the quality and quantity of the embryoids produced. Respectively: Biotechnology Department, Alberta Research Council, Agriculture Canada, Beaverlodge, Alberta, and University of Alberta, Edmonton, Alberta, Canada     

Repeated use of Bacillus subtilis cell walls for copper binding

Purified cell walls from Bacillus subtilis were repeatedly suspended in 5 mm CuCl₂ and, after removing unbound Cu, were suspended in 1% (v/v) HNO₃ to release bound Cu. The walls were then regenerated by washing in H₂O. After five cycles, copper binding actually increased slightly, probably due to enhanced exposure of binding sites in the walls. Thus bacterial walls may be used repeatedly for metal removal during bioremediation of heavy metal pollution.R.J.C. McLean is with the Department of Biology, Southwest Texas State University, 601 University Drive, San Marcos, TX 78666-4616, USA A.M. Campbell is with the Department of Chemical Engineering, Queen's University, Kingston, Ontario, K7L 3N6, Canada. P.T. Khu is with the Department of Mining Engineering, Queen's University, Kingston, Ontario, K7L 3N6, Canada. A.T. Persaud, L.E. Bickerton and D. Beauchemin are with the Department of Chemistry, Queen's University, Kingston, Ontario, K7L 3N6, Canada.     

Effects of 2,6-dichlorobenzonitrile on suspension-cultured soybean cells

2,6-Dichlorobenzonitrile, a new cellulose-synthesis inhibitor,induced remarkable cell swelling and characteristic modificationof cell form in suspension cultured soybean. The cell form wasquite similar to that induced by coumarin, but was obviouslydifferent from that induced by colchicine. ¹Present address: Department of Entomology, Division of Toxicologyand Physiology, University of California, Riverside, California92502, U.S.A. (Received April 10, 1976; )     

INHIBITORY EFFECT OF AMITROLE ON SCENEDESMUS QUADRICAUDA

The multiplication of the alga Scenedesmus quadricauda is inhibited by Amitrole (3-amino-1,2,4-triazole). This inhibition is reversed by addition of adenine to the growth medium. An electron-microscopic study has been made of the cytological changes which accompany the inhibition by Amitrole and the subsequent reversal. In the presence of Amitrole the cells accumulate a large quantity of starch which is lost very rapidly as soon as the Amitrole block is released and cell multiplication is resumed. ³Present address: Department of Biology and Botany, University of British Columbia, Vancouver, Canada.     

Analysis And Localization of the Water-Deficit Stress-Induced Gene ( lp3)

LP3 is a water-deficit-induced protein, which is highly homologous to ASR (ABA, stress and ripening) proteins. Homology was found in the C-terminal region of the putative LP3 protein while lower homologies were found in the N-terminal region. The goal of this study was to investigate the function of the LP3 protein and the mechanism of the lp3 promoter in response to water-deficit stress (WDS) and other stresses. In regenerated transgenic tobacco (T₀), expression of -glucuronidase (GUS) from the lp3 promoter-GUS construct was observed in polyethylene glycol (PEG), abscisic acid (ABA), methyl-jasmonate (MeJa), and fluridone (Flu) treatments. GUS expression was not observed following gibberellin (GA₃), 2-methyl-4-dichlorophenoxy acetic acid (2,4-D), silver nitrate, or ethephon (ethylene releasing agent) treatments. Germinated T₁ seedlings containing the lp3 promoter-GUS construct exhibited GUS activity up to 40 days postgermination. Expression could be restored when 5-azacytidine was included in the culture media, indicative of a developmentally regulated silencing mechanism involving methylation. In transgenic tobacco, the LP3 protein localized in the cell nucleus was induced by WDS and appeared to be developmentally regulated. Mailing address of Jau-Tay Wang: 4 Lane 9 Minsheng Rd., Wufeng 413, Taichung, Taiwan. Present address of Jean H. Gould: Department of Forest Science Texas A&M University College Station, Texas 77843-2135, USA; Present address of Veera Padmanabhan: Pioneer HiBred International Inc., 7250 NW 62nd Ave, Johnston, Iowa 50131-0552, USA; Present address of Ronald J. Newton: Department of Biology, East Carolina University, Greenville, North Carolina 27858-4353, USA     

Effects of Cytokinin and Light on Polyamines during the Greening Response of Cucumber Cotyledons

The cucumber cotyledon greening test was used as a model systemto study possible relationships between cytokinins and polyaminesduring the greening process. When cytokinin was applied to dark-growncotyledons, large increases in chlorophyll and putrescine levelswere observed. However, inhibition of putrescine biosynthesiswith D-arginine and difluoromethylarginine did not affect chlorophyllproduction, and applied polyamines proved inhibitory to greening.Addition of 50 mM K^$ to the cytokinin treatments increased chlorophyllsynthesis but caused a marked reduction in putrescine levels.These results indicate that the large increase in putrescinecontent that derives from cytokinin treatment of the cotyledonsis not essential for the cytokinin-induced greening response. ¹Present address: Crop Science Department, University of Guelph,Guelph, Ontario, Canada, NIG 2W1. ²Present address: Agrogen Biotechnologies Inc., 520W. 6th Ave.,Vancouver, B.C., Canada, V5Z 4H5. (Received June 29, 1987; Accepted October 9, 1987)     

Book reviews

Book reviewed in this article: Radioisotopes and Ionizing Radiations in Entomology Glenn B. Wiggins . Centennial of Entomology in Canada 1863–1963. A Tribute to Edmund M. Walker J. Forsyth : Agricultural Insects of Ghana. Z. Avidov (Editor): Studies in Agricultural Entomology and Plant Pathology. G. Domenichini : Index of Palaearctic Tetrastichinae, dans: V. Delucchi & G. Remaudiere Z. Waloff : The upsurges and recessions of the desert locust plague: an historical survey. Cell Differentiation and Morphogenesis , International Lecture Course, Wageningen, The Netherlands. April 26–29, 1965, by W. Beerman , R. J. Gautheret , P. D. Nieuwkoop , C. W. Wardlaw , V. B. Wigglesworth , E. Wolff , J. A. D. Zeevaart G. H. Yeoman & J. B. Walker : The ixodid ticks of Tanzania.     

Comparison of coulter volumes with radiometrically determined intracellular water volumes for cultured cells

Summary During methotrexate-induced differentiation of cultured human choriocarcinoma (BeWo) cells, proliferation is inhibited, morphologic and biochemical changes occur, and giant, often multinucleated, cells form. We have used the increase in cell volume as a marker of the mature syncytiotrophoblastlike phenotype. Uninduced and differentiated BeWo cells are not spherical, and theoretical considerations suggested that deviations in shape could result in significant errors in Coulter volume. To determine if the values obtained by electrical pulse sizing reflected the actual mass of BeWo cells, we have evaluated the relationship between Coulter volumes and intracellular water volumes obtained using a shape-independent estimate for eight cell types. A close correlation (r ²=0.97) was found, indicating that cell volume changes in populations of irregularly shaped cells can be accurately measured using a Coulter instrument. Supported by an operating grant from the National Cancer Institute of Canada. N.S.B. was a recipient of a studentship award from the Alberta Heritage Foundation for Medical Research. C.E.C. is a Senior Research Scientist of the National Cancer Institute of Canada. The McEachern Laboratory is a research facility of the Faculty of Medicine, University of Alberta, and the Cross Cancer Institute, Edmonton, Alberta.     

CHOICE OF BIOASSAY IN ASSESSING ACTIVITY OF ENDOGENOUS GROWTH SUBSTANCES

A chloroform extract of peelings and buds of ‘Red Pontiac’potato tubers yielded chromatographic eluates that exhibitedqualitatively and quantitatively different stimulating and inhibitingresponses on four bioassays. The essentiality of selecting asatisfactory array of bioassays, coupled with a thorough extractionprocedure, is emphasized. ¹This research was supported by United States Public HealthService Grant EF-61 ²Present address: Department of Botany, Hebrew University, Jerusalem,Israel ³Present address: Department of Agronomy, University of Tokyo,Bunkyo-ku, Tokyo     

A Requirement for Polyamines during the Cell Division Phase of Radicle Emergence in Seeds of Acer saccharum

When stratified sugar maple seeds were germinated at 5C, celldivision did not contribute to radicle emergence or to earlygrowth of the embryonic axis. Putrescine, spermidine and sperminecontents remained low throughout stratification, but followinggermination their levels rose gradually for several days andthen entered a phase of rapid accumulation concurrent with initiationof rapid cell division. When inhibitors of putrescine and polyaminebiosynthesis were applied to newly germinated seeds, levelsof the amines and cell division were markedly reduced, but cellelongation, as evidenced by growth of hypocotyls, was not affected. ¹ Present address: Department of Chemistry and Biochemistry,University of Guelph, Guelph, Ontario, Canada N1G 2W1.