Fremdsprachen
Von: Rasta, 3.5.2004 17:59 Uhr
Ich habe hier eine Menge zu Übersetzen und würde mich freuen wenn mir hier jemand helfen kann!! Ist ziehmlich speziel deshallb tue ich mir selber sehr schwer!!!

Wenn ihr ein bißchen Arbeitteilung betreibt geht`s vielleicht?!!?
Ich hoffe es gibt hier ein paar Leute die Spass dran haben :-) ist echt ne Menge hab ich festgestellt!!


ADAPTATIONS OF THE TUBE WORM

most morphologically & physiologically specialized invertebrate/bacterial symbiosis in the hydrothermal vent environment
-giant tubeworm is large animal (1-2m in length, several cm diameter), largest measured 5 ft
-found in areas of strong flow of dilute vent fluid (max temp ~15-20°C)
-live at interface between sources of chemically reactive compounds
-experience erratic bursts of sulfide-rich vent fluids mixed with bursts of oxygen-rich seawater


TUBEWORM ADAPTATIONS CONT’D

-experiences gradient of temperature along body
-have a rapid growth rate
-4 distinct body regions 1)plume (red), 2)vestimentum, 3)trunk, 4)opisthosome
-anterior plume red –coloured tip, extends in and out of chitonous, cylindrical tube
-plume resembles feather; separate filaments extending outward which contain pair of blood vessels
-plume acts like a gill (exchange of nutrients & waste product release)
-worm anchored permanently to substrate on vent

TUBEWORMS AND BACTERIA

-trophosome in trunk, houses sulfide-oxidizing bacteria deep inside
-trophosome tissue contains yellow flecks of elemental sulfur & is rich with blood vessels
-bacteria densely packed in trophosome (several trillion per gram of tissue)
-juvenile worms have a mouth and digestive tract, bacteria get inside worm by mouth
-as worm grows, mouth disappears, along with gut and fills out with bacteria
-adult worms have no mouth or digestive system present

ADAPTATIONS FOR CARBON UPTAKE & TRANSPORT

-worm’s rapid growth & complete nutritional dependence rely on organic carbon fixed by symbiotic bacteria
-due to bacteria’s location, worm must effectively transport inorganic carbon from site of uptake to site for carbon fixation
-usually net flow carbon dioxide out of heterotroph, but to satisfy demands from bacteria, net flow of carbon dioxide must be inward
-~one-half of inorganic carbon fixed by bacteria from respiratory carbon dioxide from host, remaining derived from environment around plume
-seawater contains a lot of inorganic carbon but not readily diffusible across living tissues

CARBON TRANSPORT CONT’D

-total organic carbon correlated to partial pressure of environmental CO2 & able to reach very high levels (same levels as soft drinks)
-high capacity for CO2 essential for providing symbionts with organic carbon
-such large carbon fixation rates supply more than twice the organic carbon demand of tubeworm metabolism=tremendous growth
-optimal conditions for CO2 fixation for tubeworms are moderate temperatures (22-35°C) & low oxygen conc

HEMOGLOBIN SPECIALIZATION IN TUBEWORMS

-plume of worm is highly vascularized, allowing sufficient exchange of dissolved molecules between blood and environment
-blood of vascular system rich in extracellular hemoglobin (red colour of plume)
-differs from human hemoglobin; 30X larger than human hemoglobin (increased size allows separated sites where oxygen and sulfide attaches)
-hemoglobin in the tube worm allows enzyme activity in the presence of toxic sulfide
-tubeworm hemoglobin solves problem of sulfide toxicity and nutritional demands

SULFIDE TOXICITY ADAPTATIONS IN TUBEWORMS

-hosts must supply a source of reduced sulfur in form of hydrogen sulfide, to symbionts
-hydrogen sulfide releases a lot of energy when oxidized & this energy fuels chemoautotrophic production of organic carbon by bacteria
-sulfide is extremely toxic at micrometer concentrations found at hydrothermal vents
-sulfide poisoning occurs when respiration is blocked
-the worms’ hemoglobin binds with the sulfide and keeps it from poisoning worm & also transports sulfide & oxygen from plume to troposphere for bacteria met.
-sulfide-hemoglobin interactions in tubeworms are unusual; sulfide does not compete for oxygen binding site (no toxicity)

SULFIDE TOXITY ADAPTATIONS

-by transporting sulfide bound to hemoglobins, tubeworms can concentrate sulfide from environment maintaining low internal free-sulfide concentration
-larger hemoglobin has 3X sulfide-binding capacity of smaller hemoglobin=allows animal to concentrate sulfide from environment
-high affinity for sulfide allows animal to retain sulfide when exposed to periods with low sulfide
-once in trophosome, bacteria harvest E from sulfide & generate ATP needed to fuel inorganic C fixation
-symbionts detoxify sulfide through oxidation (metabolism)
-partial oxidation leads to elemental sulfur in trophosome tissue-contributes E to bacteria

OXYGEN REQUIREMENTS FOR TUBEWORMS/SYMBIONTS

-high concentrations of hemoglobin needed to transport large amount of O2 consumed by symbionts as well as controlling sulfide toxicity & facilitating sulfide transport
-bacteria demands for oxygen can exceed 2X demand of host
-hemoglobin has high affinity for oxygen--enables worms to take up& transport large amounts of O2 to maintain low internal dissolved oxygen
-at elevated temp, tubeworm hemoglobins have reduced affinity for oxygen & increased rates of O2 dissociation
-may be important reason why O2 unloaded in trophosome (warmer) rather than the plume (cooler)

NITROGEN DEMANDS FOR TUBEWORMS/SYMBIONTS

-have isotope ratios of 15N:14N, that suggest assimilation of local inorganic nitrogen rather than organic nitrogen
-ammonia conc. in area generally low, nitrate always present in surrounding seawater
-mechanisms of nitrate uptake, concentration and transport are unknown at this time
-nitrate-reductase activity in troposphere & represents first step in inorganic nitrogen assimilation of nitrate reduced to nitrite
-nitrate respiration allows O2 concentrations around symbiotic bacteria to be very low, yet energy can be gained through process of reduction of nitrate to nitrite



  1. Antwort von Rasta 0
    Schon mal Vielen Dank!!
    Da hab ich glatt vergessen mich schon mal zu bedanken!!!
    Ich hoffe Ihr könnt mir ein bißchen weiterhelfen!!!

    DANKE
    2 Kommentare
    • von Einzelkind (abgemeldet) 1
      Re: Schon mal Vielen Dank!!
      Hallo,
      schau mal einige Threads weiter unten! Christopher hat eine wunderbar treffende Antwort geschrieben auf eine Frage von Marc!
      Lieben Gruß und viel Erfolg damit!
    • von Rasta 0
      Re^2: Schon mal Vielen Dank!!
      Hallo,
      schau mal einige Threads weiter unten! Christopher hat eine
      wunderbar treffende Antwort geschrieben auf eine Frage von
      Marc!
      Lieben Gruß und viel Erfolg damit!
      Hallo!!

      Das Problem ist, dass ich keinen Deutschen Text habe!? Ich habe nur Englisch und bräuchte die deutsche überstetzung!! Nun ist es so das derjenige, der den Text geschrieben hat, wohl auch nicht so gut Englisch konnte. Mir kommt es nämlich so vor als seien da eine Menge Fehler drin!!
      Also wenn ihr mir helfen könnt würde ich mich freuen!!!!
  2. Antwort von miranda (abgemeldet) 0
    • von Einzelkind (abgemeldet) 0
      Re^2: Übersetzung von Englisch ins Deutsche
      außerdem
      http://www.leo.org!
      lieben gruß!