DOCSLIB.ORG

Cell Size and Proportional Distance Assessment During Determination of Organelle Position in the Cortex of the Ciliate Tetrahymena

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Cell Size and Proportional Distance Assessment During Determination of Organelle Position in the Cortex of the Ciliate Tetrahymena J. Cell Set. ai, 35-46 (1976) 35 Printed in Great Britain CELL SIZE AND PROPORTIONAL DISTANCE ASSESSMENT DURING DETERMINATION OF ORGANELLE POSITION IN THE CORTEX OF THE CILIATE TETRAHYMENA D. H. LYNN AND J. B. TUCKER Department of Zoology, The University, St Andrews, Fife KY16 <)TS, Scotland SUMMARY Developing oral organelles of dividing Tetrahymena corlissi appear to be positioned by mechanisms which assess distances as a proportion of the organism's overall dimensions. In some respects, the cortex of this protozoan obeys the 'French flag' rule formulated by Wolpert for describing regulation of spatial proportions during differentiation of metazoan embryos. Dividing Tetrahymena of markedly different sizes occur when division is synchronized by starvation and refeeding. At the start of cell division, the distance between old and new mouth- parts varies proportionately with respect to cell length. In addition, determination of the site where new oral organelles will develop is apparently not directly related to the number of ciliated basal bodies which separate the 2 sets of mouthparts; the greater the distance between the old and developing sets of mouthparts, the greater the number of ciliated basal bodies in the rows between them. It is suggested that 2 distinct mechanisms are largely responsible for defining organelle position in ciliates. The new terms structural positioning and chemical signalling are denned to describe these mechanisms. INTRODUCTION Organelles are positioned in a very precise and specific fashion in many unicellular organisms. Precisely positioned organelles form particularly well ordered and charac- teristic patterns in the cortices of ciliates. The spatial complexity of these organelle arrays is comparable with the arrangement of different cell types, tissues, and organs in multicellular animals. Moreover, the body sizes of ciliates and the sizes of positional fields in multicellular animals and their embryos are quite similar (Frankel, 1974)- This fact, together with others, has led Frankel (1974) to argue that some of the mechanisms underlying the spatial specification of pattern are the same in both ciliates and multicellular animals. Universality of mechanisms for specifying posi- tional information, particularly among metazoa, has been proposed in Wolpert's (1969, 1971) theory of 'positional information'. Wolpert has emphasized the fact that positional fields are regulative. Regulative fields are capable of proportionately re- establishing the same pattern after their boundaries have been disturbed or altered. Wolpert (1969) has formalized this in his 'French flag' rule. Examples of such regula- tion are well documented for metazoan development (see Wolpert, 1969; Cooke, 1975)- 3-2 36 D.H. Lynn andj. B. Tucker Strict proportional regulation has not been clearly established for ciliates. Frankel (1974) has reviewed microsurgical experiments which demonstrate that Stentor obeys the 'French flag' rule within certain limitations. There have been several morphometric analyses which demonstrate that positioning of contractile vacuole pores in Tetrahymena (Nanney, 1966, 1967; Frankel, 1972; Doerder, Frankel, Jenkins & De Bault, 1975) and Chilodonella (Kaczanowska, 1974) is probably accomplished by assessment of the overall size of the positional field in which they develop. Kac- zanowska (1974) and Jerka-Dziadosz (1974) have discussed the congruence between the models of positional information for multicellular and unicellular organisms. Many new cortical organelles develop when a ciliate commences binary fission. Is spacing of the sites where new organelles form proportionately related to the sizes of dividing organisms ? It is difficult to assess whether such spatial regulation occurs, rather than positional specification by mechanisms relying on fixed or absolute distances, because, before starting to divide, most ciliates reach a specific, well defined size which shows little variation. However, these alternatives can be tested with the hymenostome Tetrahymena corlissi. In this species, dividing organisms of markedly different sizes occur during refeeding following a period of starvation. Little growth of the organisms takes place in the unusually short period which intervenes between the 2 fissions which follow release from starvation (Lynn, 1975). This paper examines the extent of spatial proportionality in the cortex of T. corlissi, by measuring the distances separating the sites of old and differentiating new oral organelles at the start of binary fission in organisms of varying lengths. Differences in the number of cortical fibre-lattice units situated between the 2 sets of oral organelles have also been investigated. The results are discussed in terms of recent proposals for positional determination in metazoans (Wolpert, 1969, 1971) and in ciliated protozoa (Frankel, 1974, 1975; Sonneborn, 1974). MATERIALS AND METHODS Culture techniques Tetrahymena corlissi strain WT, clone TC-2, was cultured axenically in 2 % (w/v) proteose- peptone with either o-i % yeast extract or o-i % neutralized liver digest. Dividing organisms of markedly different sizes are present after starved organisms are resupplied with nutrient culture medium. A variation of the starvation-refeeding technique described by Cameron & Jeter(i97o) was employed. A 200-ml culture of logarithmically growing T. corlissi (ca. 7000 cells/ml) was centrifuged to concentrate the organisms which were then washed twice in an inorganic 'starvation' buffer (Cameron & Jeter, 1970) and resuspended in 200 ml of starvation buffer. After 24 h, starved organisms were centrifuged down and resuspended in nutrient culture medium. The time at which the organisms started to divide again after release from starvation was ascertained by taking small samples from a culture at regular intervals, fixing the organisms in Lugol's iodine, and counting the numbers of dividing organisms in a standard volume. Experiments were conducted at 18-20 °C. Tetraliymena pyriformis strain W was cultured axenically in 1 % (w/v) proteose-peptone and o-i % yeast extract. Proportional distance assessment in Tetrahymena 37 Staining and microscopy The cortex of dividing organisms was stained with silver (Chatton & Lwoff, 1930; Corliss, 1953), protargol (McCoy, 1974) and nigrosin (MacKinnon & Hawes, 1961). Organisms were photographed with a Carl Zeiss Universal microscope fitted with bright-field, phase-contrast and Nomarski differential interference-contrast optics. Silver-stained organisms were measured with a Leitz filar ocular micrometer mounted on a Leitz Ortholux microscope. RESULTS Positioning of new mouthparts At the beginning of binary fission each organism develops one new set of mouth- parts. These form some distance from, and posterior to, the pre-existing old mouth- parts (Fig. 1). They usually develop alongside a ciliary row (kinety 1) which extends 30 fim Anterior mouthparts Kinety 1 Developing posterior mouthparts Fig. 1. Schematic scale drawing of first (I) and second (II) post-starvation dividers based on average measurements for 50 silver-stained specimens of each type of divider. d is the distance between mouthparts and / is the body length. The number of black dots in the first kinety of each divider represents the average number of basal bodies in the portion between the mouthparts. The old anterior mouthparts each include a curved undulating membrane and 3 membranelles. posteriorly along the length of the organism from the posterior end of the old set of mouthparts (Fig. 1). The distance (d) between old and new mouthparts (measured from the posterior end of the undulating membrane of the old anterior set of mouth- parts to the anterior extremity of the developing posterior set of mouthparts) has been measured for silver-stained organisms at an early stage of binary fission and stomatogenesis (Fig. 1). By this stage, the basal bodies of the developing oral ciliary organelles form a compact group but have not sorted out into the distinct arrays D.H. Lynn and J. B. Tucker Proportional distance assessment in Tetrahymena 39 which will form the undulating membrane and 3 membranelles (Fig. 1). The lengths of dividing organisms in logarithmically growing cultures {log dividers) vary between 6o-8 and 77-6/tm and their mouthparts are separated by distances of 14-1-21-8/un (Table 1). Much greater variation in these parameters is found in organisms after release from starvation. 300 .:> .* o. 200 100 00 400 500 600 70 0 800 Body length, Fig. 2. Graph showing the relationship between the distance between the mouth- parts (d) and body length (/) for 150 silver-stained dividing organisms (50 each of first and second post-starvation dividers and 50 log dividers). The line fitted by linear regression analysis has the equation d = o-3O55(/) - 2'474, where d and / are in /Jm. After transfer to the starvation buffer, the total number of organisms increased by about 10% over 24 h. The sizes of the organisms decreased as starvation pro- ceeded. After 24 h, the lengths of organisms averaged 53-3 fim (43-3-61-5/tm; N = 15) while the widths averaged 18-2 /tm (14-7-22-5 /tm; N = 15). Non-dividing organisms in logarithmically growing cultures have lengths averaging 64-6 /tm (51-1-75-6/4111; N = 15) and widths averaging 32-9fim (25-2-39-0fim; N = 15). Organisms start to divide again about 12-15 n a^-er transfer from the starvation buffer to a nutrient culture medium (see Materials and methods). During this 3-h period, division synchrony of up to 10% was achieved by the starvation-refeeding
Load more

Recommended publications
  • Wrc Research Report No. 131 Effects of Feedlot Runoff
    WRC RESEARCH REPORT NO. 131 EFFECTS OF FEEDLOT RUNOFF ON FREE-LIVING AQUATIC CILIATED PROTOZOA BY Kenneth S. Todd, Jr. College of Veterinary Medicine Department of Veterinary Pathology and Hygiene University of Illinois Urbana, Illinois 61801 FINAL REPORT PROJECT NO. A-074-ILL This project was partially supported by the U. S. ~epartmentof the Interior in accordance with the Water Resources Research Act of 1964, P .L. 88-379, Agreement No. 14-31-0001-7030. UNIVERSITY OF ILLINOIS WATER RESOURCES CENTER 2535 Hydrosystems Laboratory Urbana, Illinois 61801 AUGUST 1977 ABSTRACT Water samples and free-living and sessite ciliated protozoa were col- lected at various distances above and below a stream that received runoff from a feedlot. No correlation was found between the species of protozoa recovered, water chemistry, location in the stream, or time of collection. Kenneth S. Todd, Jr'. EFFECTS OF FEEDLOT RUNOFF ON FREE-LIVING AQUATIC CILIATED PROTOZOA Final Report Project A-074-ILL, Office of Water Resources Research, Department of the Interior, August 1977, Washington, D.C., 13 p. KEYWORDS--*ciliated protozoa/feed lots runoff/*water pollution/water chemistry/Illinois/surface water INTRODUCTION The current trend for feeding livestock in the United States is toward large confinement types of operation. Most of these large commercial feedlots have some means of manure disposal and programs to prevent runoff from feed- lots from reaching streams. However, there are still large numbers of smaller feedlots, many of which do not have adequate facilities for disposal of manure or preventing runoff from reaching waterways. The production of wastes by domestic animals was often not considered in the past, but management of wastes is currently one of the largest problems facing the livestock industry.
    [Show full text]
  • Review and Meta-Analysis of the Environmental Biology and Potential Invasiveness of a Poorly-Studied Cyprinid, the Ide Leuciscus Idus
    REVIEWS IN FISHERIES SCIENCE & AQUACULTURE https://doi.org/10.1080/23308249.2020.1822280 REVIEW Review and Meta-Analysis of the Environmental Biology and Potential Invasiveness of a Poorly-Studied Cyprinid, the Ide Leuciscus idus Mehis Rohtlaa,b, Lorenzo Vilizzic, Vladimır Kovacd, David Almeidae, Bernice Brewsterf, J. Robert Brittong, Łukasz Głowackic, Michael J. Godardh,i, Ruth Kirkf, Sarah Nienhuisj, Karin H. Olssonh,k, Jan Simonsenl, Michał E. Skora m, Saulius Stakenas_ n, Ali Serhan Tarkanc,o, Nildeniz Topo, Hugo Verreyckenp, Grzegorz ZieRbac, and Gordon H. Coppc,h,q aEstonian Marine Institute, University of Tartu, Tartu, Estonia; bInstitute of Marine Research, Austevoll Research Station, Storebø, Norway; cDepartment of Ecology and Vertebrate Zoology, Faculty of Biology and Environmental Protection, University of Lodz, Łod z, Poland; dDepartment of Ecology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia; eDepartment of Basic Medical Sciences, USP-CEU University, Madrid, Spain; fMolecular Parasitology Laboratory, School of Life Sciences, Pharmacy and Chemistry, Kingston University, Kingston-upon-Thames, Surrey, UK; gDepartment of Life and Environmental Sciences, Bournemouth University, Dorset, UK; hCentre for Environment, Fisheries & Aquaculture Science, Lowestoft, Suffolk, UK; iAECOM, Kitchener, Ontario, Canada; jOntario Ministry of Natural Resources and Forestry, Peterborough, Ontario, Canada; kDepartment of Zoology, Tel Aviv University and Inter-University Institute for Marine Sciences in Eilat, Tel Aviv,
    [Show full text]
  • Arthropods of the Convoy Range They Will Provide Information on the Succession, Nutrition, and Other Features of These Organisms
    Beginning on December 10, 1967, and ending on February 5, 1968, visits were made about every five days to Coast Lake at Cape Royds to obtain en- vironmental and biological data, the former including maximum and minimum air and water temperatures, temperatures at the times of visits, cloud cover, and wind conditions. The types of lake-water data ob- tained are lisited below. pH Fe/Fe Cl- Dissolved oxygen Mg, Mn NO2—N Turbidity and color K NH3—N Conductivity Na, Li Ca Total hardness SO4--NO3—N Alkalinity PO41 ortho and meta Spathidium spathula, from a meltwater pond near Palmer The quantitative biological data consisted of sur- Station. face and bottom samples from nine stations arranged in transects across the lake. The samples were col- of Palmer Station, the British stations on Adelaide lected on millipore filters, then fixed and mounted on Island and the Argentine Islands, and near Argen- slides. Total species counts are being made of the tinas Almirante Brown base and the Chilean refuge Protozoa, primarily of ciliates. In addition, rotifers, near Adelaide Island. Near Palmer Station, collec- tardigrades, nematodes, and algae are being counted tions were made on Norsel and Bonaparte Points and because of their importance in understanding the on Cormorant, Humble, and Litchfield Islands. nutritional and competitive roles of Protozoa. Smears were made of blood collected from 17 fish, Generally, the lake water is characterized by low and special slides were made of free-living and cul- temperatures (0°C.-5°C.), dissolved oxygen satura- tured Protozoa. Data on communities of Protozoa tion, very high pH (9.2-9.9), and variable ionic con- and freshwater crustaceans were obtained from fresh- tent.
    [Show full text]
  • Changes in Nuclear Structure During Binary Fission in the Ciliate Nassula
    J. Cell Sci. 2, 481 -498 (1967) 481 Printed in Great Britain CHANGES IN NUCLEAR STRUCTURE DURING BINARY FISSION IN THE CILIATE NASSULA J. B. TUCKER Department of Zoology, University of Cambridge, and Department of Zoology, Indiana University, Bloomington, Indiana, U.S.A.* SUMMARY During binary fission intranuclear spindles are formed in the three micronuclei and in the macronucleus. The nuclear envelopes remain intact throughout nuclear division. At one stage all the nuclei are linked together by the formation of membrane bridges in continuity with the outer membranes of their envelopes. Three types of filamentous structure have been distinguished in the spindles: microtubules of diameter 210-240 A, fine branching filaments, and filaments which have a C-shaped transverse profile and a diameter of about 240 A, for which the term C-filament is suggested. At metaphase a polar vesicle is situated at each pole of the micronuclei but centrioles are absent. During late anaphase a long central spindle, called here a separation spindle, is situated inside eachmicronucleus and elongates between the separating chromosomes. The nuclear pores of both types of nuclei are partly filled with dense material. In long, late anaphase micronuclei, pores are abundant in the parts of the envelope surrounding the ends of the nuclei but are rarely found elsewhere. Large numbers of ribosome-like granules are attached to the outer surfaces of the micronuclear envelopes where they sheathe the separation spindles. INTRODUCTION This paper is mainly confined to a description of structural changes in the spindles and the nuclear envelopes of the dividing macronucleus and micronuclei of the ciliate Nassula during binary fission.
    [Show full text]
  • The Ecology of Marine Microbenthos Ii. the Food of Marine Benthic Ciliates
    OPHELIA, 5: 73-121 (May 1968). THE ECOLOGY OF MARINE MICROBENTHOS II. THE FOOD OF MARINE BENTHIC CILIATES TOM FENCHEL Marine Biological Laboratory, 3000 Helsinger, Denmark CONTENTS Abstract 73 Introduction 73 Material and methods. .. .......... .. 74 General part. ............................ .. 75 The mechanical properties of the food. 75 Specificity in choice of food. ............. .. 78 Special part. ............................... 84 Orcer Gymnostomatida .. 84 Order Trichostomatida .................•.. 97 Order Hymenostomatida " 100 Order Heterotrichida 108 Order Odontostomatida 113 Order Oligotrichida I 13 Order Hypotrichida , 114 References. .............................. .. I 19 ABSTRACT The paper brings together knowledge on the food of marine benthic ciliates with the exception of sessile forms. References are given to 260 species of which 90 have been studied by the author. The classification of ciliates according to their natural food and the specificity in choice of food is discussed and the ecological significance of discrimination of food according to size is emphasized. INTRODUCTION In a previous study (Fenchel, 1967) the quantitative importance of protozoa - especially ciliates - in marine microbenthos was investigated and it was concluded Downloaded by [Copenhagen University Library], [Mr Tom Fenchel] at 01:12 22 December 2012 that the ciliates play an important role in certain sediments, viz. fine sands and sulphureta. A further analysis of the structure and function of the microfauna communities requires knowledge of factors which influence the animal popula- tions. Of these food is probably one of the most important. Thus Faure-Fremiet 74 TOM FENCHEL (1950a, b, 1951a), Fenchel & Jansson (1966), Lackey (1961), Noland (1925), Perkins (1958), Picken (1937), Stout (1956) and Webb (1956) all stress the im- portance of the food factor for the structure of protozoan communities.
    [Show full text]
  • Mesodinium Pulex MP 0004563695.P1
    Pseudocohnilembus persalinus KRX05445.1 Ichthyophthirius multifillis XP_004037375.1 Tetrahymena thermophila XP_001018842.1 Cryptocaryon irritans k141_54336.p1 Pseudocohnilembus persalinus KRX05059.1 Tetrahymena thermophila XP_001017094.3 Ichthyophthirius multifillis XP_004029899.1 Nassula variabilis k141_18808.p1 Cparvum_a_EAK89612.1 Paramecium tetraurelia XP_001437839.1 Paramecium tetraurelia XP_001436783.1 Paramecium tetraurelia XP_001426816.1 Paramecium tetraurelia XP_001428490.1 Colpoda aspera k119_31549.p1 Aristerostoma sp. MMETSP0125-20121206_1718_1 Aristerostoma sp. MMETSP0125-20121206_9427_1 Pseudomicrothorax dubius k141_16595.p1 Furgasonia blochmanni k141_76537.p1 Nassula variabilis k141_25953.p1 Protocruzia adherens MMETSP0216-20121206_9085_1 Heterocapsa artica_d_MMETSP1441-20131203_3016_1 Cryptocaryon irritans k141_19128.p1 Balantidium ctenopharyngodoni k141_68816.p2 Afumigatus_XP_754687.1 Panserina_f_CAP64624.1 Afumigatus_XP_755116.1 Panserina_f_CAP61434.1 Euplotes focardii MMETSP0206-20130828_15472_1 Pseuodokeronopsis sp. MMETSP1396-20130829_12823_1 Heterosigma akashiwo-CCMP2393-20130911_268255_1 Hakashiwo2_s_Heterosigma-akashiwo-CCMP452-20130912_5774_1 Phytophthora infestans_s_EEY69906.1 Mantarctica_v_MMETSP1106-20121128_20623_1 Mantarctica_v_MMETSP1106-20121128_10198_1 Mantarctica_v_MMETSP1106-20121128_26613_1 Mantoniella_v_MMETSP1468-20131203_2761_1 Dunaliella tertiolecta_v_CCMP1320-20130909_4048_1 Tetraselmis_v_MMETSP0419_2-20121207_8020_1 Tastigmatica_v_MMETSP0804-20121206_11479_1 Tetraselmis chui_v_MMETSP0491_2-20121128_10468_1
    [Show full text]
  • Classification of the Phylum Ciliophora (Eukaryota, Alveolata)
    1! The All-Data-Based Evolutionary Hypothesis of Ciliated Protists with a Revised 2! Classification of the Phylum Ciliophora (Eukaryota, Alveolata) 3! 4! Feng Gao a, Alan Warren b, Qianqian Zhang c, Jun Gong c, Miao Miao d, Ping Sun e, 5! Dapeng Xu f, Jie Huang g, Zhenzhen Yi h,* & Weibo Song a,* 6! 7! a Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 8! China; b Department of Life Sciences, Natural History Museum, London, UK; c Yantai 9! Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China; d 10! College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China; 11! e Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystem, 12! Xiamen University, Xiamen, China; f State Key Laboratory of Marine Environmental 13! Science, Institute of Marine Microbes and Ecospheres, Xiamen University, Xiamen, 14! China; g Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China; h 15! School of Life Science, South China Normal University, Guangzhou, China. 16! 17! Running Head: Phylogeny and evolution of Ciliophora 18! *!Address correspondence to Zhenzhen Yi, [email protected]; or Weibo Song, 19! [email protected] 20! ! ! 1! Table S1. List of species for which SSU rDNA, 5.8S rDNA, LSU rDNA, and alpha-tubulin were newly sequenced in the present work. ! ITS1-5.8S- Class Subclass Order Family Speicies Sample sites SSU rDNA LSU rDNA a-tubulin ITS2 A freshwater pond within the campus of 1 COLPODEA Colpodida Colpodidae Colpoda inflata the South China Normal University, KM222106 KM222071 KM222160 Guangzhou (23° 09′N, 113° 22′ E) Climacostomum No.
    [Show full text]
  • Topic: Introduction to Protozoa:Structure, Life
    TOPIC: INTRODUCTION TO PROTOZOA:STRUCTURE, LIFE AND LOCOMOTION IN PARAMOECIUM LECTURE NO:03 B.SC PART 1 ZOOLOGY(HONS.)-PAPER I-GROUP A CHAPTER 2 DATE: 26TH MARCH 2020 AUTHOR: DR.NIRMAL KUMARI Class1. Telosporea Spores without polar capsules or filaments. Sporozoites elongated, microgamete flagellated. Trophozoties with one nucleus only. Subclass -1. Gregarinia Trophozoites large and found in the gut and body cavities (i.e. extracellular) of invertebrates. Zygote non motile. Male and female gametes merogamous. Sporozoites found in sporocyst. Parasites of invertebrates. Eg. Monocystis, Gregarine. Subclass- 2. Coccidia Trophozoites small and intracellular. Gametophytes dimorphic. Sporozoites in sporocysts. Blood or gut parasites of vertebrates. Eg- Eimeria, Isospora. Class 2. Toxoplasmea Spores not formed. Only asexual reproduction. E. g- Toxoplasma. Class 3. Haplosporea Spores with spore cases. Parasitic of fish and invertebrates. Pseudopodia may be present but no flagella. Reproduction by schizogony only (asexual) E.g. Ichthyosporidium, Haplosporidium Subphylum- III. Cnidospora Trophozoite has many nuclei. Spore formation occurs throughout life. Spores contain polar capsules with polar filaments. Class 1. Myxosporidea Spores develop from several nuclei. Spore within two or three valves. Order -1. Myxosporida. Spores large and with a bivalve membrane. Polar capsule 1, 2 or 4; each with a filament. Tropozoites amoeboid. Eg. Myxidium. Order- 2. Actinomyxida Spores large and with a trivalved membrane. Polar capsule 3, each with a filament. Eg. Triactinomyxon, Sphaeractinomyxon. Class-2. Microsporidea Spores small and with a univalved membrane. With or without polar capsule E.g. Nosema. Subphylum – IV. Ciliophora Body organization complex. Presence of cilia as feeding and locomotory organelles at some stage in the life cycle.
    [Show full text]
  • Cyanobacterial Removal by a Red Soil-Based Flocculant and Its Effect on Zooplankton: an Experiment with Deep Enclosures in a Tropical Reservoir in China
    Environmental Science and Pollution Research https://doi.org/10.1007/s11356-018-2572-3 WATER ENVIRONMENT PROTECTION AND CONTAMINATION TREATMENT Cyanobacterial removal by a red soil-based flocculant and its effect on zooplankton: an experiment with deep enclosures in a tropical reservoir in China Liang Peng1 & Lamei Lei1 & Lijuan Xiao1 & Boping Han1,2 Received: 14 September 2017 /Accepted: 18 June 2018 # The Author(s) 2018 Abstract As one kind of cheap, environmentally-friendly and efficient treatment materials for direct control of cyanobacterial blooms, modified clays have been widely concerned. The present study evaluated cyanobaterial removal by a red soil-based flocculant (RSBF) with a large enclosure experiment in a tropical mesotrophic reservoir, in which phytoplankton community was domi- nated by Microcystis spp. and Anabaena spp. The flocculant was composed of red soil, chitosan and FeCl3. Twelve enclosures −1 were used in the experiment: three replicates for each of one control and three treatments RSBF15 (15 mg FeCl3 l ), RSBF25 −1 −1 (25 mg FeCl3 l ), and RSBF35 (35 mg FeCl3 l ). The results showed that the red soil-based flocculant can significantly remove cyanobacterial biomass and reduce concentrations of nutrients including total nitrogen, nitrate, ammonia, total phosphorus, and orthophosphate. Biomass of Microcystis spp. and Anabaena spp. was reduced more efficiently (95%) than other filamentous cyanobacteria (50%). In the RSBF15 treatment, phytoplankton biomass recovered to the level of the control group after 12 days and cyanobacteria quickly dominated. Phytoplankton biomass in the RSBF25 treatment also recovered after 12 days, but green algae co-dominated with cyanobacteria. A much later recovery of phytoplankton until the day of 28 was observed under RSBF35 treatment, and cyanobacteria did no longer dominate the phytoplankton community.
    [Show full text]
  • The Role of the Cytoskeleton in the Motility of Coccidian Sporozoites
    J. Cell Set. 50, 345-359 (1981) 345 Printed in Great Britain © Company of Biologittt Limited 1981 THE ROLE OF THE CYTOSKELETON IN THE MOTILITY OF COCCIDIAN SPOROZOITES D. G. RUSSELL AND R. E. SINDEN Department of Zoology and Applied Entomology, Imperial College, London SW7 2AZ, England SUMMARY The sporozoites of Eimeria tenella and Eimeria acervulina show bending, pivoting and gliding motility. All these types of motility occur intermittently and with decreasing frequency during the life of a sporozoite. Gliding is the only locomotive action expressed by these sporozoites and is only seen when the sporozoites are in contact with the substratum. All gliding sporozoites adopt a set pattern of body ' attitudes', which suggests that locomotion involves a fixed body shape. The microtubule inhibitors, colchicine, griseofulvin, vinblastine sulphate and nocodazole, have no effect on sporozoite motility. Ultrastructural examination reveals, in addition, that they have no effect on the subpellicular microtubules. The microfilament inhibitor, cytochalasin B, completely, and reversibly, inhibits pivoting and gliding but bending is only slightly depressed by the drug. High magnesium ion concentration inhibits all motility completely. The cell membrane was readily labelled with fluorescein isothiocyanate-conjugated cationized ferritin, the label was rapidly capped and shed from the posterior of the sporozoite. This capping reaction takes place only during sporozoite locomotion. The membrane label was seen to ' move' backwards relative to the sporozoite at the same rate as the sporozoite moved forwards relative to the substratum. The substratum and the leading edge of the cap remained static relative to each other. Both capping and locomotion are sensitive to low temperature and cytochalasin B.
    [Show full text]
  • Responses of Intermittent Pond Ciliate Populations and Communities to in Situ Bottom-Up and Top-Down Manipulations
    AQUATIC MICROBIAL ECOLOGY Vol. 42: 293–310, 2006 Published March 29 Aquat Microb Ecol Responses of intermittent pond ciliate populations and communities to in situ bottom-up and top-down manipulations Oksana P. Andrushchyshyn, A. Katarina Magnusson, D. Dudley Williams* Surface and Groundwater Ecology Research Group, Department of Life Sciences, University of Toronto at Scarborough, 1265 Military Trail, Ontario M1C 1A4, Canada ABSTRACT: Pond physicochemical characteristics and bottom-up effects were more important than top-down effects in governing ciliate community structure in 2 adjacent intermittent ponds in South- ern Ontario, Canada. The ciliates showed a bimodal seasonal pattern with abundances peaking early and late in the hydroperiods, and the communities showed a strong seasonal succession of species — only 15% of the 162 ciliate species were present throughout the hydroperiods. Less than half of the species occurred in both ponds. Adding riparian leaf litter to large pond enclosures affected several physicochemical variables, increased bacterial abundance, and promoted the appearance of particu- lar species — many of which are known to be associated with nutrient- or organic matter-enriched conditions. This treatment resulted in higher ciliate abundance (mainly small-sized bacterivores) and lower ciliate diversity in mid-hydroperiod in one of the ponds. The removal of plant litter generally produced effects in the physicochemical variables that were opposite to those seen in the leaf litter addition, and resulted in a 15% decrease in the proportion of ciliate bacterivores in one pond. The effects of top-down manipulations (i.e. prevention of aerial colonization of insects) were minor. Many treatment effects were season-, and pond-specific.
    [Show full text]
  • Cercozoa Apusozoa Heliozoa Phytomyxids Haplosporidia Filosa Foraminifera Radiolaria Opisthokonts Fungi
    PROTISTS GROUPS (ref. 1) Cercozoa Apusozoa Heliozoa Phytomyxids Haplosporidia Filosa Foraminifera Radiolaria Opisthokonts Fungi Animals Nuclearids Ichthyosporea Choanoflagellates Amoebozoa Lobosea Slime Molds Archamoebae Excavates Oxymonads Trimastix Hypermastigotes Trichomonads Retortamonads Diplomonads Carpediamonas Jakobids (core) Discicristates Kinetoplastids Diplonemids Euglenids Heterolobosea Chromists Cryptomonads Haptophytes Opalinids Bicosoecids Oomycetes Diatoms Brown Algae Alveolates Ciliates Colpodellids Apicomplexa Dinoflagellates Oxyrrhis Perkinsus Plantae Plants (Plants and other autotrophs ignored.) Charophytes Chlorophytes Red Algae Glaucophytes SUMMARY: NUMBER OF SPECIES IN EACH GROUP CONTAINING INFORMATION ON PLOIDY AND LIFE STYLE Diploid Parasite (~1468-1963 species) Some Lobosea (<10 species?, ref. 2, p. 7-8) Some Diplomonads (~8 species, ref. 2, p. 202) Some Trypanosomes (unknown fraction of ~495 species are diploid, ref. 2, p. 218) Some Oomycetes (>250 species, ref. 2, p. 672-678) Some Ciliates (~1200 species; ref. 3, p. 40) Haploid Parasite (~2573-3068 species) All Phytomyxids (~29 species, ref. 2, p. 399) Some Trichomonads (~4 species, ref. 4) Some Trypanosomes (unknown fraction of ~495 species are haploid, ref. 2, p. 218) All Apicomplexa (~2400 species, ref. 2, p. 549) Some Dinoflagellates (~140 species, ref. 5, p. 1) Diploid Non-Parasite (~7284 species) All Heliozoa (~90 species, ref. 2, p. 347) Most Lobosea (~200 species, ref. 2, p. 3) Some Oxymonads (~20 species, ref. 6) Some Hypermastigotes (~4 species, ref. 6) Most Diplomonads (~100 species, ref. 2, p. 202) Most Ciliates (>6300 species = 85% of 7500, ref. 2, p. 498) All Opalinids (~400 species, ref. 2, p. 239) Some Oomycetes (>170 species, ref. 2, p. 672-678) Haploid Non-Parasite (~1465 species) Dictyostelium (~50 species, ref. 2, p.
    [Show full text]