OBT Speciation by the Germany BIOCHEM Model Franz Baumgrtner - - PowerPoint PPT Presentation

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Feb 04, 2023 42 likes •162 views

OBT- speciation dynamics as viewed from biochemistry F Baumgartner OBT Speciation by the Germany BIOCHEM Model Franz Baumgrtner Institut fr Radiochemie Technische Universitt Munich The BIOCHEM model assumes that OBT = X + C B ound T

SLIDE 1

OBT- speciation dynamics as viewed from biochemistry F Baumgartner Germany

OBT Speciation by the BIOCHEM Model

Franz Baumgärtner Institut für Radiochemie Technische Universität Munich

SLIDE 2

The BIOCHEM model assumes that

OBT = X + C Bound Tritium = XBTburied+ CBT

X = N,O,S buried = non-accessible by the

rinsing solvent

OBT = Carbon Bound Tritium = CBT (a biological product) caused by photosynthesis or incorporation Test of BIOCHEM aspects by analysis of OBT formation

This OBT definition contradicts the common opinion:

SLIDE 3

Therefore, No difference in the course of XBT- and CBT- formation

In order to identify biological growth the fact is used:

“

biological growth is composed of a

I. Self-Accelerating Phase (Brody 1945, 1964)

But,

Mono-molecular reactions like isotope- exchange follow the same course

and a

II. Self-Inhibiting Phase (Brody 1945,1964)

Formation Time Product OBT = B*2t/τ A Formation Time Product OBT = A*(1-2–(t-to)/τ) = A – C*2t/τ A Formation Time Product OBT = A*(1-2–(t-to)/τ) = A – C*2t/τ OBT = B*2t/τ A

Thus, Biological formation contains Phase I and Phase II

SLIDE 4

without atomic shell inclusive atomic shell

Fundamental differences in XBT- and CBT-formation rate species mobility is XBT CBT the movement of cationic or anionic tritium is

very fast reaction rate conventional reaction rate like electrons

(mass related)

like atoms

(mass related)

T+

Cationic Tritium

T

Anionic Tritium is formed from HTO by

SLIDE 5

168 336 504 672 840 1008117613441512 Hours HTO Exposure 5.000 10.000 15.000 20.000 25.000 30.000 35.000 40.000 OBT [pCi/gH]

14d 7d 21d 28d 35d 42d 49d 56d 63d

Tomato plants, 9 weeks exposed to atmospheric HTO (F.S.Spencer 1984: ONTARIO HYDRO 84‐69‐K) OBT dynamics of Abrupt start of HTO exposure

TEST OF NON‐BIOLOGICAL OBT FORMATION

24 48 72 Hours HTO Exposure 1.000 2.000 3.000 4.000 5.000 6.000 OBT[pCi/gH] 1.000 2.000 3.000 4.000 5.000 6.000 TFWT[pCi/mL] 24 48 72 Hours HTO Exposure 1.000 2.000 3.000 4.000 5.000 6.000 OBT[pCi/gH] 1.000 2.000 3.000 4.000 5.000 6.000 TFWT[pCi/mL]

Mechanism of OBT formation recognized at the very beginning

OBT, TFWT form synchroneously early OBT = XBTburied

because of no accelerating phase

= OBT FORMATION WITHOUT PHASE I

SLIDE 6

Ribonuclease T1, Arni R, Heinemann U,Tokuoka R, Saenger W, 1988

multi ms

Molecular visualisation of the early window: formation of proteins

Consequences of the rapid triton mobility: Aminoacids Peptide chain Secondary Quartenary Structures ms ms ms µs

(we consider the case Ribonuclease)

HTO µs

H+/T+

Ribonuclease T1, Takahashi K,1985

Early OBT window and a Late OBT window

SLIDE 7

Molecular visualisation of the late window: H+migration into proteins

case Ribonuclease)

weeks months years

HTO Similar in polysaccharides, cellulose, starch

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168 336 504 672 840 1008 1176 1344 1512

Hours HTO Exposure

5.000 10.000 15.000 20.000 25.000 30.000 35.000 40.000 OBT [pCi/gH] 14d 7d 21d 28d 35d 42d 49d 56d 63d

2 x OBT courses suspected to be caused by photosynthesis No photosynthesis because of 6 weeks delay Photosynthesis

The XBTburied fraction in tomato OBT

Comparision abrupt + chronic HTO exposure

chronic HTO forms 5x larger OBT than abrupt OBT photosynthetic OBT

Late H+/T+ After 7 weeks abrupt meets chronic OBT

abrupt HTO start

Early H+/T+

chronic HTO exposure ∼10% Spence 1984: “H+/T+ exchange paralleling photosynthesis“

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Chronic HTO exposure

OBT content/compartment Compart‐ ment No x Compart‐ ment No y Timesteps

H+migration weeks into months bio‐polymers years

Timesteps OBT content/compartment Compart‐ ment No x Compart‐ ment No y Timesteps OBT content/compartment Compart‐ ment No x Compart‐ ment No y

Abrupt start of HTO exposure

Timesteps OBT content/compartment Compart‐ ment No x Compart‐ ment No y

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0,01 0,1 1 10 100 Days after Transplantation 500 1000 1500 2000

Freshwater Mussels Exposed to 4.500 Bq/L HTO

0,01 0,1 1 10 100 Days after Transplantation 500 1000 1500 2000

Freshwater Mussels Exposed to 4.500 Bq/L HTO

0,01 0,1 1 10 100 Days after Transplantation 500 1000 1500 2000 OBT [BqL-1]

Freshwater Mussels Exposed to 4.500 Bq/L HTO

The XBTburied fraction in mussel OBT

Final OBT 100%

Larvae Sperm

∆ =1d 62% OBTfast =XBT (swallowing) 18% OBTfast =XBT (respiration) 20% OBT slow by food OBT reproduction free

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⇒ fast and late window of OBT formation Conclusion OBT formation (abrupt and chronic, fast and slow) can be modeled by respecting ⇒ OBT = XBT buried + CBT ⇒ XBH/compartment from food tables ⇒ XBTburied estimated from XBH

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OBT Speciation by the BIOCHEM Model

OBT = X + C Bound Tritium = XBTburied+ CBT

X = N,O,S buried = non-accessible by the

OBT = Carbon Bound Tritium = CBT (a biological product) caused by photosynthesis or incorporation Test of BIOCHEM aspects by analysis of OBT formation

Fundamental differences in XBT- and CBT-formation rate species mobility is XBT CBT the movement of cationic or anionic tritium is

T+

T

The XBTburied fraction in tomato OBT

⇒ fast and late window of OBT formation Conclusion OBT formation (abrupt and chronic, fast and slow) can be modeled by respecting ⇒ OBT = XBT buried + CBT ⇒ XBH/compartment from food tables ⇒ XBTburied estimated from XBH

Thank you for your attention