DOCSLIB.ORG

Obecné Znaky Metabolismu + Bioenergetika

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Obecné Znaky Metabolismu + Bioenergetika Metabolism • General concept of metabolism + Bioenergetics • Cellular respiration (glykolysis + CKC + oxidative phosphorylation) • Sacharide metabolism + photosynthesis • Lipid metabolism • Metabolism of nitrous compounds Obecné znaky metabolismu + bioenergetika BUNĚČNÁ TEORIE Robert Hook (1667) "buňka" 1. Buňky tvoří veškerou živou hmotu (x viry). 2. Veškeré buňky pocházejí z jiných buněk (x samoplození). 3. Informace se předávají z generace na generaci. 4. V buňkách látky podléhají chemickým přeměnám. 5. Buňky reagují na vnější podněty. Otevřené systémy: tok látek, energie a informací dovnitř a ven dynamická rovnováha → ustálený stav Pravá rovnováha → smrt organismu Metabolic types (trofika, trofé = výživa): Energy source: light→ phototroph chemical reaction(redox) → chemotrophs Proton/electron donor acceptor Anorganic Organic Oxygen Other lithotrophs organotrophs aerobic anaerobic (líthos = stone) Fermentace: „disproporcionace“ Např.: C6H12O6 2 CH3-CH(OH)-COOH C6H12O6 2 CH3-CH2-OH + 2CO2 To be continued…….. Carbon source: anorganic → autotrophs organic → heterotrophs Common metabolic types METABOLISM Carbon source Proton source Proton example acceptor photolithotrophs CO2 H2O CO2 Green parts of (autotrophic) plant photolithotrophs Organic comp H2O (CO2) Some (heterotrophic) photosynthetic bacteria Photoorganotrophs Organic comp. Organic comp CO2 Some algae nad (heterotrophic) bacteria chemoorganotrophs Organic comp Organic comp O2 Animals, aerobic aerobic MO 2- Chemoorganotrophs Organic comp Organic comp SO4 Soil anaerobic - Anaerobic respiration NO3 bacteria - HCO3 Chemoorganotrophs Organic comp Organic comp ---- yeasts fermenting chemolithotrophs CO2 H2S, CH4, NH3, O2 sulphur bacteria, H2 nitrifying Metabolism katabolism anabolism Gain of energy Consumption of energy Interconected and coordinated + amfibolic and anaplerotic pathways Basic concept of metabolism and bioenergetics autorophs heterotrophs Main metabolic pathways http://expasy.org/tools/pathways/ Overview of catabolism chemoorganotrophic aerobic FATS POLYSACCHARIDES PROTEINS Stage 1 fatty acids, glucose, amino acids glycerol other sugars Stage 2 acetyl CoA H2O O2 CoA Stage 3 – v oxidative e Krebs cycle v phosphorylation CO2 ATP ADP + Pi 14 Anabolismus production phase of metabolism – biosynthesis Increasing complexity of products requires energy - ATP Reductive character – requires reducing agent - NADPH + H+ 1. stage: intermediates of 2. a 3. phase of catabolism (CKC) precursors 2. stage: biosynthesis of bulding blocs - monomers 3. stage: biosynthesis of polymers from activated monomers Summary Anabolic Catabolic • Divergent process • Convergent process • Reductive • Oxidative • End products are complex • End products are simple molecules molecules • Requires Energy • Releases Energy • Builds something • Breaks something down Localized in different compartmets Common : intermediates, some enzymatic reactions, starting and end products Metabolic pathway series of chemical reactions occurring within a cell Metabolic pathway involves the step-by-step modification of an initial molecule to form another product course of metabolic pathways: linear, branched, cyclic, spiral ATP = common currency ? ATP = společná měna 1. Electrostatic repulsion Enzyme 2. Resonance “handle” stabilization O- HO P O- O Bioenergetics Gibbs free energy -most useful termodynamic quantity for biological systems - measures the "useful" or process-initiating work obtainable from a reaction at a constant temperature and pressure G = H - TS Free energy is a measure of how far a reaction. is from equilibrium G r x n = Gp r o d u c t s - Gs u b s t r a t e s A + B P G rxn G A + B P rxn A + B P Free Energy G > 0 G < 0 G = 0 endergonic exergonic equilibrium How is ∆G related to ∆Go? The concentration dependence of G for a chemical reaction is: Ratio of products to reactants under the reaction conditions { o [products] ∆G = ∆G + R Tln ( [substrates] ) Gas constant Temperature (8.31 J/ Ko-mol) (in K)o o Under standard conditions:∆ G = ∆ G In bichemistry: G’o = free energy released for a reaction: • Under Standard Conditions – 1M reactants and products – 25oC – Ph 7.0 • Where Concentration Terms are Ignored for: – water – Protons G´ = G0´ + RT ln [produkty]/[reaktanty] Direction of the given reaction depends on the concentration of reactants and products Example: DAP GA3P G (kJ mol-1) (M) (M) 1,0 1,0 + 7,7 (G0) 2,0 x 10-1 9,0 x 10-3 0 (G) 1,0 x 10-1 1,0 x 10-4 - 9,5 (G) 1,0 x 10-4 1,0 x 10-1 + 24,8 (G) To be continued……… Exergonic reactions: G < 0 Endergonic reactions: G > 0 - Proceeds spontaneously does not proceed sponatneously - does not require energy - catabolism generally – don’t exist But : ligases active transport anabolism (celkově) ? Solution: coupling of reactions Glucose + Pi ↔ glucose phosphate + H2O ΔGº’ = +13.8 kJ/mol Glucose + Pi ↔ glucose 6-phosphate + H2O ΔGº’ = +13.8 kJ/mol ATP + H2O ↔ ADP + Pi ΔGº’ = -30.5 kJ/mol Glucose+ ATP ↔ glucose 6-phosphate+ ADP ΔGº’ = -16.7 kJ/mol Synthesis of ATP in organisms Substrate phosphorylation S-P + ADP S + ATP (transferase) G°’ADP = -30,5 kJ/mol S1-S2 + ADP + Pi S1 + S2 + ATP (+ H2O) (ligase) …. ATP synthesis in organisms Membrane phosphorylations: ADP + Pi ATP + H2O (hydrolases) ● oxidative phosphorylation ( in mitochondria) ● Photophosphorylation (chloroplasts) Usage of ATP • chemical work: transferases and ligases • Osmotic work – active transport of compounds (against concentration gradient) • Mechanical work: actomyosin complex (muscle contraction), flagela, cytoskeleton • Regulatory work – signal transduction Membrane transport Biological membranes are semi-permeable, very limited number of molecules can cross the membrane by plain diffusion Pasive transport Mobil trnasporter -valinomycin Chanel transporter- gramicidin Protein transporters Transport of compounds through permanent pores - porins Molecular sieve Gap junction Aperture like function Pasive vs active transport © Espero Publishing, s.r.o. Active tra nsport deltaGtransport= -RT ln Cvně/C uvnitř .
Load more

Recommended publications
  • Aerobic Respiration
    Life is based on redox • All energy generation in biological systems is due to redox (reduction-oxidation) reactions Aerobic Respiration: + - C6H12O6 + 6 H2O ==> 6 CO2 + 24 H +24 e oxidation electron donor (aka energy source) + - (O2+ 4H + 4e ==> 2H2O) x6 reduction electron acceptor --------------------------------------- C6H12O6 + 6 O2 ==> 6 CO2 + 6 H2O overall reaction (24 electrons) Types of bacterial metabolisms • While eukaryotes only reduce O2 and oxidize organic compounds, prokaryotes can use a variety of electron donors and acceptors, organic and inorganic. - • Aerobic respiration: e acceptor is O2 - • Anaerobic respiration: e acceptor is not O2 • Fermentation: e- donor and acceptor are organic molecules • Chemolithotrophy: e- donor and acceptor are inorganic molecules • Phototrophy: e- donor is light and e- acceptor is either organic or inorganic all microorganisms energy source? chemical light chemotroph phototroph carbon source? carbon source? organic organic CO CO compound 2 compound 2 chemoheterotroph chemoautotroph photoheterotroph photoautotroph e- acceptor? Nitrifying and sulfur- use H O to reduce CO ? oxidizing bacteria 2 2 green non-sulfur and O Other than O 2 2 purple non-sulfur bacteria anoxygenic oxygenic photosynthesis: photosynthesis: green sulfur and most bacteria Organic Inorganic cyanobacteria compound compound purple sulfur bacteria fermentative organism anaerobic respiration: nitrate, sulfate, Fe(III) Aerobic or anaerobic respiration Chemolithotrophy Important molecules Redox Electron Carrier: for example the
    [Show full text]
  • MIXOTROPHY in FRESHWATER FOOD WEBS a Dissertation
    MIXOTROPHY IN FRESHWATER FOOD WEBS A Dissertation Submitted to the Temple University Graduate Board In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY by Sarah B. DeVaul May 2016 Examining Committee Members: Robert W. Sanders, Advisory Chair, Biology Erik E. Cordes, Biology Amy Freestone, Biology Dale Holen, External Member, Penn State Worthington Scranton © Copyright 2016 by Sarah B. DeVaul All Rights Reserved ii ABSTRACT Environmental heterogeneity in both space and time has significant repercussions for community structure and ecosystem processes. Dimictic lakes provide examples of vertically structured ecosystems that oscillate between stable and mixed thermal layers on a seasonal basis. Vertical patterns in abiotic conditions vary during both states, but with differing degrees of variation. For example, during summer thermal stratification there is high spatial heterogeneity in temperature, nutrients, dissolved oxygen and photosynthetically active radiation. The breakdown of stratification and subsequent mixing of the water column in fall greatly reduces the stability of the water column to a vertical gradient in light. Nutrients and biomass that were otherwise constrained to the depths are also suspended, leading to a boom in productivity. Freshwater lakes are teeming with microbial diversity that responds to the dynamic environment in a seemingly predictable manner. Although such patterns have been well studied for nanoplanktonic phototrophic and heterotrophic populations, less work has been done to integrate the influence of mixotrophic nutrition to the protistan assemblage. Phagotrophy by phytoplankton increases the complexity of nutrient and energy flow due to their dual functioning as producers and consumers. The role of mixotrophs in freshwater planktonic communities also varies depending on the relative balance between taxon-specific utilization of carbon and energy sources that ranges widely between phototrophy and heterotrophy.
    [Show full text]
  • Evolution of Oxygenic Photosynthesis
    EA44CH24-Fischer ARI 17 May 2016 19:44 ANNUAL REVIEWS Further Click here to view this article's online features: • Download figures as PPT slides • Navigate linked references • Download citations Evolution of Oxygenic • Explore related articles • Search keywords Photosynthesis Woodward W. Fischer, James Hemp, and Jena E. Johnson Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125; email: wfi[email protected] Annu. Rev. Earth Planet. Sci. 2016. 44:647–83 Keywords First published online as a Review in Advance on Great Oxidation Event, photosystem II, chlorophyll, oxygen evolving May 11, 2016 complex, molecular evolution, Precambrian The Annual Review of Earth and Planetary Sciences is online at earth.annualreviews.org Abstract This article’s doi: The origin of oxygenic photosynthesis was the most important metabolic 10.1146/annurev-earth-060313-054810 innovation in Earth history. It allowed life to generate energy and reducing Copyright c 2016 by Annual Reviews. power directly from sunlight and water, freeing it from the limited resources All rights reserved of geochemically derived reductants. This greatly increased global primary productivity and restructured ecosystems. The release of O2 as an end prod- Access provided by California Institute of Technology on 07/14/16. For personal use only. Annu. Rev. Earth Planet. Sci. 2016.44:647-683. Downloaded from www.annualreviews.org uct of water oxidation led to the rise of oxygen, which dramatically altered the redox state of Earth’s atmosphere and oceans and permanently changed all major biogeochemical cycles. Furthermore, the biological availability of O2 allowed for the evolution of aerobic respiration and novel biosynthetic pathways, facilitating much of the richness we associate with modern biology, including complex multicellularity.
    [Show full text]
  • Chapter 4: PROKARYOTIC DIVERSITY
    Chapter 4: PROKARYOTIC DIVERSITY 1. Prokaryote Habitats, Relationships & Biomes 2. Proteobacteria 3. Gram-negative and Phototropic Non-Proteobacteria 4. Gram-Positive Bacteria 5. Deeply Branching Bacteria 6. Archaea 1. Prokaryote Habitats, Relationships & Biomes Important Metabolic Terminology Oxygen tolerance/usage: aerobic – requires or can use oxygen (O2) anaerobic – does not require or cannot tolerate O2 Energy usage: phototroph – uses light as an energy source • all photosynthetic organisms chemotroph – acquires energy from organic or inorganic molecules • organotrophs – get energy from organic molecules • lithotrophs – get energy from inorganic molecules …more Important Terminology Carbon Source: autotroph – uses CO2 as a carbon source • e.g., photoautotrophs or chemoautotrophs heterotroph – requires an organic carbon source • e.g., chemoheterotroph – gets energy & carbon from organic molecules Oligotrophs require few nutrients, the opposite of eutrophs or copiotrophs Facultative vs Obligate (or Strict): facultative – “able to, but not requiring” • e.g., facultative anaerobes can survive w/ or w/o O2 obligate – “absolutely requires” • e.g., obligate anaerobes cannot survive in O2 Symbiotic Relationships Symbiotic relationships (close, direct interactions) between different organisms in nature are of several types: • e.g., humans have beneficial bacteria in their digestive tracts that also benefit from the food we eat (mutualism) Microbiomes All the microorganisms that inhabit a particular organism or environment (e.g., human or
    [Show full text]
  • 7.014 Lectures 16 &17: the Biosphere & Carbon and Energy Metabolism
    MIT Department of Biology 7.014 Introductory Biology, Spring 2005 7.014 Lectures 16 &17: The Biosphere & Carbon and Energy Metabolism Simplified Summary of Microbial Metabolism The metabolism of different types of organisms drives the biogeochemical cycles of the biosphere. Balanced oxidation and reduction reactions keep the system from “running down”. All living organisms can be ordered into two groups1, autotrophs and heterotrophs, according to what they use as their carbon source. Within these groups the metabolism of organisms can be further classified according to their source of energy and electrons. Autotrophs: Those organisms get their energy from light (photoautotrophs) or reduced inorganic compounds (chemoautotrophs), and their carbon from CO2 through one of the following processes: Photosynthesis (aerobic) — Light energy used to reduce CO2 to organic carbon using H2O as a source of electrons. O2 evolved from splitting H2O. (Plants, algae, cyanobacteria) Bacterial Photosynthesis (anaerobic) — Light energy used to reduce CO2 to organic carbon (same as photosynthesis). H2S is used as the electron donor instead of H2O. (e.g. purple sulfur bacteria) Chemosynthesis (aerobic) — Energy from the oxidation of inorganic molecules is used to reduce CO2 to organic carbon (bacteria only). -2 e.g. sulfur oxidizing bacteria H2S → S → SO4 + - • nitrifying bacteria NH4 → NO2 → NO3 iron oxidizing bacteria Fe+2 → Fe+3 methane oxidizing bacteria (methanotrophs) CH4 → CO2 Heterotrophs: These organisms get their energy and carbon from organic compounds (supplied by autotrophs through the food web) through one or more of the following processes: Aerobic Respiration (aerobic) ⎯ Oxidation of organic compounds to CO2 and H2O, yielding energy for biological work.
    [Show full text]
  • Extremophile Cards
    hloroexus aurantiacus “Color-changer, green to orange” einococcus radiodurans yrococcus furiosus Domain: Bacteria “Terrible berry, survives radiation” “Raging reball” Habitat: Hot springs around the world, including Domain: Bacteria Domain: Archaea Yellowstone National Park. Habitat: Widespread, including deserts, hot springs, Habitat: Hydrothermal vents in ocean oor; rst Energy Source: Mixotroph (phototroph and high mountains, polar regions and animal gut. discovered near volcanic islands in Italy. chemotroph). Mainly uses light energy from the sun. In the dark, can use chemical energy from inorganic Energy Source: Chemotroph. Uses chemical energy Energy Source: Chemotroph. Uses chemical energy compounds (sulphur and hydrogen). from organic compounds. from organic compounds. Challenges to Life: Heat, UV exposure, changing Challenges to Life: Dehydration, cold, acidic pH, Challenges to Life: Heat, pressure, changes in levels of light and oxygen radiation, oxidative damage oxygen levels when vent uids contact sea water Adaptation: Can rebuild its genome, after radiation Adaptation: A protein called reverse gyrase helps breaks it into hundreds of fragments, using a unique maintain DNA structure in extreme heat. High Adaptation: Can do both photosynthesis (like DNA-repair mechanism. Produces antioxidants that temperatures tend to unzip double-stranded DNA. plants) and respiration (like animals), allowing it to protect proteins from radiation damage. Reverse gyrase twists DNA so much it can’t unravel. survive a range of light and oxygen levels. It is green during photosynthesis and orange during respiration. Talent: Radioresistant. Survives short doses of Talent: Hyperthermophile. rives in extremely hot radiation up to 5,000 Gy. Grows under constant temperatures. Grows best at 100°C (212°F), Talent: ermophile.
    [Show full text]
  • Identifying the Missing Steps of the Autotrophic 3-Hydroxypropionate
    Identifying the missing steps of the autotrophic SEE COMMENTARY 3-hydroxypropionate CO2 fixation cycle in Chloroflexus aurantiacus Jan Zarzyckia, Volker Brechtb, Michael Mu¨ llerb, and Georg Fuchsa,1 aMikrobiologie, Fakulta¨t fu¨ r Biologie, Universita¨t Freiburg, Scha¨nzlestrasse 1, D-79104 Freiburg, Germany; and bInstitut fu¨r Pharmazeutische Wissenschaften, Universita¨t Freiburg, Albertstrasse 25, D-79104 Freiburg, Germany Edited by Donald A. Bryant, Pennsylvania State University, University Park, PA, and accepted by the Editorial Board October 10, 2009 (received for review July 27, 2009) The phototrophic bacterium Chloroflexus aurantiacus uses a yet metabolite, from which all building blocks for polymers can be unsolved 3-hydroxypropionate cycle for autotrophic CO2 fixation. derived. It starts from acetyl-CoA, with acetyl-CoA and propionyl-CoA In nature 6 mechanisms to assimilate CO2 into cell material have carboxylases acting as carboxylating enzymes. In a first cycle, been established (1). In the reductive pentose phosphate (Calvin– (S)-malyl-CoA is formed from acetyl-CoA and 2 molecules of bicar- Benson–Bassham) cycle discovered about 50 years ago, CO2 reacts bonate. (S)-Malyl-CoA cleavage releases the CO2 fixation product with a 5-carbon sugar yielding 2 carboxylic acids from which the glyoxylate and regenerates the starting molecule acetyl-CoA. Here sugar is regenerated (2). This cycle operates in plants, algae, we complete the missing steps devoted to glyoxylate assimilation. cyanobacteria, and in aerobic or facultative anaerobic proteobac- In a second cycle, glyoxylate is combined with propionyl-CoA, an teria. The presence of the key enzyme, ribulose 1,5-bisphosphate intermediate of the first cycle, to form ␤-methylmalyl-CoA.
    [Show full text]
  • Impacts of Seasonality and Nutrients on Microbial Mat Community Structure and Function
    MARINE ECOLOGY PROGRESS SERIES Vol. 123: 207-216. 1995 Published July 20 Mar Ecol Prog Ser Impacts of seasonality and nutrients on microbial mat community structure and function J. Pinckney, H. W. Paerl, M. Fitzpatrick University of North Carolina at Chapel Hill, Institute of Marine Sciences, 3431 Arendell Street. Morehead City, North Carolina 28557, USA ABSTRACT. To understand the mechanisms responsible for seasonal fluctuations in growth and N2 fixation in intertidal microbial mat communties, we quantified seasonal changes in mat community composition, related these changes to die1 and seasonal N2 fixation rates, and evaluated community responses (growth, N2 fixation, composition) to long-term (22 d) nutrient addition bioassays. A tem- perate intertidal cyanobacterial mat community, located in coastal North Carolina, USA, was sampled at monthly intervals for 1 yr (1993-94) to determine changes in community composition. The abun- dances of major phototrophic groups were quantified based on the relative concentrations of taxa- specific photopigments (chlorophylls and carotenoids). The most abundant phototrophs were cyano- bacteria, diatoms, and photosynthetic bacteria. Mat blomass and community composition underwent marked changes on both monthly and seasonal scales and corresponded with seasonal shifts in the dlel patterns of N2 fixation. Diatom biomass increased during periods of low N2 fixation. Nutnent (nitrate and phosphate) addition bioassays indicated that both cyanobacterial and diatom growth were N limited. Cyanobacteria were able to circumvent N llmltation by N2 fixation. The addition of high con- centrations of N (100 ,pM NaNO,) in combination with P (100 ~JMNaH2P04) resulted In an Increase (163'Y") in the relative abundance of diatoms The addition of P alone more than doubled N2 fixation rates and cyanobacterial abundance increased (+34'h) relative to diatoms.
    [Show full text]
  • Becoming-Phototroph
    DasQuestões,n#6, setembro/dezembro, 2018 Becoming-Phototroph Ewen Chardronnet, Aliens in Green Humalga - photos by Spela Petric and Robertina Sebjanic In a 2015 short story written by science fiction author Kim Stanley Robinson,1 a glimpse of a very green future is offered: in a near future where the iGEM 2 Registry of Standard Biological Parts has significantly grown, synthetic biologists discover bio-bricks in the catalogue that may be combined to make synthetic chloroplast and thus create photosynthesizing human cells. Tattoo needles are modified in order to inject chloroplast- fibroblasts into human skin, in the manner of an ordinary tattoo. The biologists formed a limited liability corporation called SunSkin, but soon they decide to go open source, as photosynthesis is a natural process. "Once they published the recipe, and the knowledge spread that human photosynthesis worked, the injection method as such became what you might call generic. (…) when you photosynthesize sunlight you will be less hungry. You might also spend more of your day outdoors in the sun, that’s right, and subsequently decide that you didn’t need quite as much food or heating as before. Or clothing. Or housing, that’s right. I don’t see all these green naked people wandering around sleeping under tarps in the park like you seem to, but granted, there have been some changes in consumption. Did changes in consumption cause 1 Oral Argument, Kim Stanley Robinson, retrieved Jan, 21, 2016 from http://www.tor.com/2015/12/07/oral-argumentkim-stanley-robinson/ 2 The International Genetically Engineered Machine (iGEM) Competition Foundation organises every year student competition in Synthetic Biology.
    [Show full text]
  • Synthetic Biology Approach for Hydrocarbon Production In
    Cocultivation of Algae and Bacteria for Improved Productivity and Metabolic Versatility Pacific Rim Summit on Industrial Biotechnology and Bioenergy October 10-12, 2012 Vancouver, Canada Axenic Cultures in Algal Biotechnology A. Gene/pathway inactivation • Current approaches use axenic (pure) cultures of microalgae and/or 3-PGA cyanobacteria Photosynthesis • Productivity is manipulated by Fatty acids imposing environmental or genetic Carbohydrate perturbations (starch, glycogen) TAGs storage • Examples: A) Inactivation of competing pathways to redirect flux towards B. Nutrient limitation specific products 3-PGA B) Nutrient (N, S) limitation to Photosynthesis inhibit growth and enhance storage product accumulation -N Monomer blocks for Storage polymers growth (nucleotides, (carbohydrates, amino acids, etc) lipids) Axenic Culture Challenges • Process engineering: mass-transfer limitations involving gaseous substrate CO2 O2 delivery (CO2) and product removal (O2) delivery removal • Growth physiology: balance the energy input with the downstream biosynthetic RuBisCo processes (growth vs. storage compounds) • Metabolic engineering: coordination of Photosynthesis 3-PGA various pathways needed; changes in expression and/or activity levels may have Storage Growth ACC unanticipated secondary consequences upon product yields. Some functions are Lipids Hydrocarbons subject to product inhibition or allosteric regulation (e.g., RuBisCo photorespiration; acetyl-CoA carboxylase regulation by palmitoyl-CoA). Co-Existence of Algae & Bacteria in Nature
    [Show full text]
  • Planktonic Food Web Structure at a Coastal Time-Series Site I
    Deep–Sea Research Part I 121 (2017) 14–29 Contents lists available at ScienceDirect Deep–Sea Research I journal homepage: www.elsevier.com/locate/dsri Planktonic food web structure at a coastal time-series site: I. Partitioning of MARK microbial abundances and carbon biomass ⁎ David A. Carona, , Paige E. Connella, Rebecca A. Schaffnerb, Astrid Schnetzerc, Jed A. Fuhrmana, Peter D. Countwayd, Diane Y. Kima a Department of Biological Sciences, University of Southern California, 3616 Trousdale Parkway, Los Angeles, CA 90089-0371, USA b Maine Department of Environmental Protection, 17 State House Station, Augusta, ME 04333-0017, USA c Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, Raleigh, NC 27695, USA d Bigelow Laboratory for Ocean Sciences, East Boothbay, ME 04544, USA ARTICLE INFO ABSTRACT Keywords: Biogeochemistry in marine plankton communities is strongly influenced by the activities of microbial species. Microbial abundance Understanding the composition and dynamics of these assemblages is essential for modeling emergent Microbial biomass community-level processes, yet few studies have examined all of the biological assemblages present in the Viruses plankton, and benchmark data of this sort from time-series studies are rare. Abundance and biomass of the Bacteria entire microbial assemblage and mesozooplankton ( > 200 µm) were determined vertically, monthly and Protists seasonally over a 3-year period at a coastal time-series station in the San Pedro Basin off the southwestern Zooplankton Time-series coast of the USA. All compartments of the planktonic community were enumerated (viruses in the femtoplankton size range [0.02–0.2 µm], bacteria + archaea and cyanobacteria in the picoplankton size range [0.2–2.0 µm], phototrophic and heterotrophic protists in the nanoplanktonic [2–20 µm] and microplanktonic [20–200 µm] size ranges, and mesozooplankton [ > 200 µm].
    [Show full text]
  • Ecophysiology of Mixotrophs
    Ecophysiology of mixotrophs Erwin Schoonhoven January 19, 2000 Contents 1 Introduction 3 1.1 Definition of the mixotroph . 3 2 Different strategies in mixotrophy 6 3 Mixotrophic organisms and their ways of mixotrophic feeding 8 3.1 Mixotrophic organisms . 8 3.1.1 Phytoplankton . 8 3.1.2 Planktonic ciliates . 8 3.1.3 Cyanobacteria . 9 3.1.4 Zooplankton, multicellular organisms . 9 3.2 Mixotrophic feeding . 9 3.2.1 Obligate mixotrophs . 9 3.2.2 Facultative mixotrophs . 10 3.2.3 `True' facultative mixotrophs . 14 4 Basics of feeding 16 4.1 Usage of both strategies in a obligate mixotroph . 16 4.2 Switching in a facultative mixotroph . 16 4.2.1 Facultative mixotroph that is obligate phototrophic . 17 4.2.2 Facultative mixotroph that is obligate heterotrophic . 17 4.3 Switching in the `true' facultative mixotroph . 18 5 Conceptual dynamics of feeding 20 5.1 Usage of both strategies in the obligate mixotroph . 20 5.2 Switching in the facultative mixotroph . 21 5.2.1 Facultative mixotroph that is obligate phototrophic . 22 5.2.2 Facultative mixotroph that is obligate heterotrophic . 23 5.3 Dynamics of feeding in the `true' facultative mixotroph . 24 6 Models for mixotrophy 27 6.0.1 A list of data on the ecophysiology of mixotrophs . 28 7 Symbiosis and mixotrophy, the same thing? 29 8 Conclusions 31 2 Chapter 1 Introduction 1.1 Definition of the mixotroph Mixotrophy is defined as the capability of one organism to be autotrophic and heterotrophic at the same time. Therefor an organism that can survive in water as a chemolitho-autotroph and, at the same time, is capable of ingestion and digestion of organic compounds from human blood, is called a mixotroph.
    [Show full text]