LISTSERV mailing list manager LISTSERV 16.5

Help for ISOGEOCHEM Archives


ISOGEOCHEM Archives

ISOGEOCHEM Archives


ISOGEOCHEM@LIST.UVM.EDU


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Proportional Font

LISTSERV Archives

LISTSERV Archives

ISOGEOCHEM Home

ISOGEOCHEM Home

ISOGEOCHEM  September 2018

ISOGEOCHEM September 2018

Subject:

Re: Autoclaving bio- and geopolymers affects hydrogen isotopes

From:

"Ambrose, Stanley H" <[log in to unmask]>

Reply-To:

Stable Isotope Geochemistry <[log in to unmask]>

Date:

Fri, 14 Sep 2018 19:35:41 +0000

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (291 lines)

Arndt,

Thanks very much for your important information about protein D/H exchange at high temperatures.  

UV sterilizers does not raise temperatures. Because it is a dry process, it should of course not leach any compounds from the sample. Experiments would still be worthwhile to check for UV effects on isotopes, particularly Compound-specific analyses.

Specimens should be laid on the bare UV box rack and turned over after an hour or so.  2 hours may be adequate.  Cheap models (less than $100) are widely available.  If more control on intensity is needed, then the more expense DNA UV annealing devices (they look like microwave ovens) might be a better choice.

Stanley H. Ambrose, Professor 
Department of Anthropology
University of Illinois, Urbana
Urbana, IL 61801 USA
217 244-3504
http://www.anthro.illinois.edu/people/ambrose
[log in to unmask]
 

On 9/14/18, 1:59 PM, "Stable Isotope Geochemistry on behalf of Schimmelmann, Arndt" <[log in to unmask] on behalf of [log in to unmask]> wrote:

Stan's comment about autoclaving having an effect on the 2H/1H of keratin (as well as of collagen, other biopolymers, kerogen, humic acids) is on target. The organic hydrogen in complex bio- and geopolymers spans a wide range of exchangeability with H2O. Some organic H-positions exchange very fast, while other chemical positions require higher activation energies and take their time. Then there is some potentially exchangeable organic H that is occluded in the interior of the dense organic matrix. H2O needs to diffuse to those locations before any exchange can occur. Deeply embedded, potentially exchangeable organic H behaves like non-exchangeable H during "equilibration" at lower temperatures. During autoclaving, H2O can reach positions at elevated temperature and pressure that equilibration with water vapor at lower temperature cannot exchange with rapidly. Hence, autoclaving as an aggressive form of equilibration effectively equilibrates much of the organic H in organic m!
 atter with water and overprints the bulk 2H/1H ratio. This overprinting at higher temperature cannot be reversed later at lower temperature, at least not fast. Many years ago, I made comparative H-equilibration experiments at different temperatures and can send publications upon request.
Cheers,
Arndt Schimmelmann

-----Original Message-----
From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On Behalf Of Ambrose, Stanley H
Sent: Friday, 14 September, 2018 12:13 PM
To: [log in to unmask]
Subject: Re: Autoclaving feathers for bulk N and C stable isotope analysis?

Would autoclaving (steam) affect D/H analysis of keratin.
Would UV sterilization be adequate?
I use a cheap hair salon type UV cabinet for sterilizing water and anything else that might be needed (weigh paper, disposable gloves, drill bits centrifuge tubes and plastic bags) for samples that may be used for ancient DNA analysis. This should kill any DNA, but I don't know if will kill bugs.

After UV treatment, dirty, unfiltered water samples from natural water holes in Kenya sat on my lab counter for a year in screw cap centrifuge tubes (irradiated in the tubes) and were completely stable. No algae 9or grew, no biogenic gas pressure.

Stanley H. Ambrose, Professor 
Department of Anthropology
University of Illinois, Urbana
Urbana, IL 61801 USA
217 244-3504
http://www.anthro.illinois.edu/people/ambrose
[log in to unmask]
 

On 11/27/16, 2:29 PM, "Stable Isotope Geochemistry on behalf of Robert Van Hale" <[log in to unmask] on behalf of [log in to unmask]> wrote:

Hi Travis,
There is a mechanical advantage to steaming of feathers - that is to make them subsequently easy to ball mill and indicating that this treatment causes structural change. Without steaming, the feather will be recovered undamaged from our rolling ball mills. I milled a large amount of feather for laboratory control materials after boiling 30 minutes at 1.5 bar, obtaining a 100 um powder.
See you
Robert

-----Original Message-----
From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On Behalf Of Travis Horton
Sent: Sunday, 27 November 2016 11:32 a.m.
To: [log in to unmask]
Subject: Re: [ISOGEOCHEM] Autoclaving feathers for bulk N and C stable isotope analysis?

Thank you Wolfram, Sergei, Len and others!

We will be exploring alternative 'sterilisation' approaches that don't involve autoclaving but remain acceptable to New Zealand biosecurity.  In the meantime, our plan will be to analyse some autoclaved and non-autoclaved feathers that are not subject to biosecurity sterilisation requirements.  

I hope to send a post with a general summary of our 'autoclaving experiment' results in the coming month.  It seems to me that it would be very interesting to also run the compound specific stable isotopes on these same autoclaved vs. non-autoclaved feathers, perhaps resulting in an RCMS manuscript.  I'll get in touch with my fellow NZ isotopists to see if any of them are interested in running the compound specifics as my lab is not able to do those analyses.

I wonder also if different feathers with different pigmentations and different feather structures/types/positions/ages would respond differently considering the fact that autoclaving will change protein structures?  Perhaps another can of worms for another day, but I've always been curious about how differences in pigmentation might influence individual feather isotopic compositions (and how these individual differences compare to homogenates derived from multiple feathers collected from the same individual).  Such information would be important to isotope tracing of bird movements/migrations between systems with distinctly different foodchain isotope architectures. These are not the primary topics of the current study (which is on Antarctic penguin feathers and Hg pathways through Ross Sea foodchains), but still very worth pursuing in my opinion.

Thanks for all your thoughts and knowledge sharing!  You guys are the best!

Travis





________________________________________
From: Stable Isotope Geochemistry [[log in to unmask]] on behalf of Wolfram Meier-Augenstein (aps) [[log in to unmask]]
Sent: Saturday, November 26, 2016 10:10 PM
To: [log in to unmask]
Subject: Re: [ISOGEOCHEM] Autoclaving feathers for bulk N and C stable isotope analysis?

There is no might about it.  The whole point of sterilization by autoclaving is to break down proteins.

Steam hydrolysis will not just break up intra-molecular hydrogen bonds or disulfide bonds between adjacent Cys residues thus changing protein structure.  Hydrolysis also breaks up peptide bonds. This process will result in at least partial formation of small oligopeptide pieces, and even in loss of individual AA residues. Terminal AAs of unravelled protein chains (or peptide fragments) would be most vulnerable.

Individual AAs and small oligopeptides could easily be lost (not on account of volatility but on account of solubility) thus changing THE BULK C and N isotopic composition in a measurable way.

Incidentally, steam hydrolyzed poultry feather meal is used as feed for livestock to replace more expensive protein sources.  Steam hydrolysis increases digestibility of feather protein.



-----Original Message-----
From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On Behalf Of Sergei Verenitch
Sent: 25 November 2016 23:00
To: [log in to unmask]
Subject: Re: [ISOGEOCHEM] Autoclaving feathers for bulk N and C stable isotope analysis?

Even if autoclaving might change structural composition of some proteins, I don¹t see how it can change THE BULK C and N isotopic values of feathers, unless the process breaks it down to light volatile compounds, which highly unlikely.




On 2016-11-25, 6:21 AM, "Stable Isotope Geochemistry on behalf of Wolfram Meier-Augenstein (aps)" <[log in to unmask] on behalf of [log in to unmask]> wrote:

>Depending on material to be autoclaved, autoclaving conditions range 
>from
>4 minutes at 132°C to 30 minutes at 121°C.  More to the point, 
>autoclaving is carried out under excess pressure.  Flash sterilization 
>at 132°C for 4 minutes is carried out at a pressure of 30 psi (2.07 bar)!
>
>The only types of protein (relatively) immune to such treatment are 
>prions.  Breaking down prions requires 60 min at 132°C.
>
>So, while typical autoclaving time may be short, it more than makes up 
>for this by doubling the amount of pressure compared to ambient.  Hence 
>the term "steam hydrolysis" for the underlying chemical reaction.
>Breaking a peptide bond is a hydrolysis reaction.
>
>If these were my samples and if the biosecurity people insist on 
>sterilization, I would explore other options of sterilization such as 
>gamma-irradiation or UV radiation.  Having said that, if the main 
>concern is to get rid of avian flu viruses I doubt UV radiation will suffice.
>
>
>-----Original Message-----
>From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On 
>Behalf Of Leonard Wassenaar
>Sent: 25 November 2016 10:27
>To: [log in to unmask]
>Subject: Re: [ISOGEOCHEM] Autoclaving feathers for bulk N and C stable 
>isotope analysis?
>
>The short answer below is not quite "fit for purpose".
>
>The problem with quoting that particular paper (aimed at archaeological
>issues) in this context, is their heated water exposure times - showing 
>minor and/or variable effects on C/H/N isotopes on non-homogenized wool 
>(not feathers) - is from 5-60 days!!!
>
>They show no data for minute-scale  preparative / sterilization 
>exposures, and even after 5 days of exposure 100 % of raw wool mass was 
>retained at 80 C.  They did not appear to control for residual moisture 
>content (for H or O), nor wool intra-sample isotopic heterogeneity for 
>all of the isotopes.  And they used median delta values with no 
>uncertainty at experimental exposure time=0, which suggests to me the 
>latter is a rather important point.  Nevertheless it is a nice work, 
>and does show important potential isotopic and structural changes that 
>are here particularly relevant to impacted archaeological wool and hair 
>samples.
>
>Autoclaving takes only 15-20 minutes, and will likely have a negligible 
>isotopic effect on whole feathers (I am NOT saying for all organics in 
>general).  Any autoclaving impact on whole feathers is likely to fall 
>within intra-sample CHNS isotopic variance, or even analytical 
>measurement uncertainty.  There lots of avian papers to show this, for 
>H at least.  I'd be interested to hear what others have found what 
>autoclaving does to CNS of feathers, if anything.
>
>Is alcohol sterilization an option?  (caveats for 13C).
>
>If in doubt, try before-and-after autoclaving snippets to see for 
>yourself.  I guess the problem is they won't give you the "before" sample.
>
>Len
>
>-----Original Message-----
>From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On 
>Behalf Of [log in to unmask]
>Sent: Friday, 25 November 2016 09:27
>To: [log in to unmask]
>Subject: Re: [ISOGEOCHEM] Autoclaving feathers for bulk N and C stable 
>isotope analysis?
>
>Hi Travis,
>
>The short answer is yes; exposing proteins to steam under pressure and 
>temperatures >100°C will change their stable isotopic composition. The 
>whole point of autoclaving (aka steam hydrolysis) is to sterilise 
>samples by destroying (hydrolysing) or at least denaturising protein 
>structures so as to nullify any infectious properties they might have had.
>
>As for the effect of hot water on keratin, Isabella von Holstein has 
>published a nice paper looking at changes in stable isotopic signature 
>with increasing temperature; cf. Figure 6 in:  I.C.C von Holstein, K.E.H.
>Penkman, E.E. Peacock and M.J. Collins (2014): "Wet degradation of 
>keratin proteins: linking amino acid, elemental and isotopic 
>compositions", Rapid Commun. Mass Spectrom., 28, 2121-2133.
>
>I sympathize with your biosecurity dept's worries about avian flu and 
>the like, but I wonder if they would be amenable to a solution 
>involving secure transport of the samples to your lab on the basis that 
>samples will be destroyed completely during the analytical process.
>
>Best,
>
>Wolfram
>
>
>-----Original Message-----
>From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On 
>Behalf Of Travis Horton
>Sent: 25 November 2016 00:51
>To: [log in to unmask]
>Subject: [ISOGEOCHEM] Autoclaving feathers for bulk N and C stable 
>isotope analysis?
>
>Howdy folks,
>
>New Zealand biosecurity would like us to autoclave imported feathers 
>prior to transfer to our stable isotope analytical facility for bulk C 
>and N stable isotope analyses.
>
>I'm not familiar with what autoclaving does to keratin and its isotopic 
>composition, thus I don't know if autoclaving the feathers would alter 
>the isotopic compositions.
>
>Any thoughts, comments, experiences or references to published works 
>would be immensely appreciated!
>
>Best,
>
>Travis
>
>This email may be confidential and subject to legal privilege, it may 
>not reflect the views of the University of Canterbury, and it is not 
>guaranteed to be virus free. If you are not an intended recipient, 
>please notify the sender immediately and erase all copies of the 
>message and any attachments.
>
>Please refer to http://www.canterbury.ac.nz/emaildisclaimer for more 
>information.
>
>----------
>
>This email has been scanned for spam and viruses by Proofpoint 
>Essentials. Visit the following link to report this email as spam:
>https://eu1.proofpointessentials.com/index01.php?mod_id=11&mod_option=l
>ogi
>tem&mail_id=1480035079-G9sA3-5ixVsU&r_address=w.meier-augenstein%40rgu.ac.
>uk&report=1
>
>________________________________
>
>Robert Gordon University is the top university for graduate jobs in the 
>UK HESA July 2015
>
>
>Robert Gordon University, a Scottish charity registered under charity 
>number SC 013781.
>
>This e-mail and any attachment is for authorised use by the intended
>recipient(s) only. It may contain proprietary material, confidential 
>information and/or be subject to legal privilege. It should not be 
>copied, disclosed to, retained or used by, any other party. If you are 
>not an intended recipient then please promptly delete this e-mail and 
>any attachment and all copies and inform the sender. Please note that 
>any views or opinions presented in this email are solely those of the 
>author and do not necessarily represent those of Robert Gordon 
>University. Thank you.
>This email message is intended only for the use of the named recipient.
>Information contained in this email message and its attachments may be 
>privileged, confidential and protected from disclosure. If you are not 
>the intended recipient, please do not read, copy, use or disclose this 
>communication to others. Also please notify the sender by replying to 
>this message and then delete it from your system.
>
>----------
>
>This email has been scanned for spam and viruses by Proofpoint 
>Essentials. Visit the following link to report this email as spam:
>https://eu1.proofpointessentials.com/index01.php?mod_id=11&mod_option=l
>ogi
>tem&mail_id=1480069627-96qgIdAoTsv2&r_address=w.meier-augenstein%40rgu.ac.
>uk&report=1

----------

This email has been scanned for spam and viruses by Proofpoint Essentials. Visit the following link to report this email as spam:
https://eu1.proofpointessentials.com/index01.php?mod_id=11&mod_option=logitem&mail_id=1480115009-BiIJy%2BOANR-y&r_address=w.meier-augenstein%40rgu.ac.uk&report=1

________________________________

Robert Gordon University is the top university for graduate jobs in the UK HESA July 2015


Robert Gordon University, a Scottish charity registered under charity number SC 013781.

This e-mail and any attachment is for authorised use by the intended recipient(s) only. It may contain proprietary material, confidential information and/or be subject to legal privilege. It should not be copied, disclosed to, retained or used by, any other party. If you are not an intended recipient then please promptly delete this e-mail and any attachment and all copies and inform the sender. Please note that any views or opinions presented in this email are solely those of the author and do not necessarily represent those of Robert Gordon University. Thank you.
This email may be confidential and subject to legal privilege, it may not reflect the views of the University of Canterbury, and it is not guaranteed to be virus free. If you are not an intended recipient, please notify the sender immediately and erase all copies of the message and any attachments.

Please refer to http://www.canterbury.ac.nz/emaildisclaimer for more information.

Top of Message | Previous Page | Permalink

Advanced Options


Options

Log In

Log In

Get Password

Get Password


Search Archives

Search Archives


Subscribe or Unsubscribe

Subscribe or Unsubscribe


Archives

December 2019
November 2019
October 2019
September 2019
August 2019
July 2019
June 2019
May 2019
April 2019
March 2019
February 2019
January 2019
December 2018
November 2018
October 2018
September 2018
August 2018
July 2018
June 2018
May 2018
April 2018
March 2018
February 2018
January 2018
December 2017
November 2017
October 2017
September 2017
August 2017
July 2017
June 2017
May 2017
April 2017
March 2017
February 2017
January 2017
December 2016
November 2016
October 2016
September 2016
August 2016
July 2016
June 2016
May 2016
April 2016
March 2016
February 2016
January 2016
December 2015
November 2015
October 2015
September 2015
August 2015
July 2015
June 2015
May 2015
April 2015
March 2015
February 2015
January 2015
December 2014
November 2014
October 2014
September 2014
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007
May 2007
April 2007
March 2007
February 2007
January 2007
December 2006
November 2006
October 2006
September 2006
August 2006
July 2006
June 2006
May 2006
April 2006
March 2006
February 2006
January 2006
December 2005
November 2005
October 2005
September 2005
August 2005
July 2005
June 2005
May 2005
April 2005
March 2005
February 2005
January 2005
December 2004
November 2004
October 2004
September 2004
August 2004
July 2004
June 2004
May 2004
April 2004
March 2004
February 2004
January 2004
December 2003
November 2003
October 2003
September 2003
August 2003
July 2003
June 2003
May 2003
April 2003
March 2003
February 2003
January 2003
December 2002
November 2002
October 2002
September 2002
August 2002
July 2002
June 2002
May 2002
April 2002
March 2002
February 2002
January 2002
December 2001
November 2001
October 2001
September 2001
August 2001
July 2001
June 2001
May 2001
April 2001
March 2001
February 2001
January 2001
December 2000
November 2000
October 2000
September 2000
August 2000
July 2000
June 2000
May 2000
April 2000
March 2000
February 2000
January 2000
December 1999
November 1999
October 1999
September 1999
August 1999
July 1999
June 1999
May 1999
April 1999
March 1999
February 1999
January 1999
December 1998
November 1998
October 1998
September 1998
August 1998
July 1998
June 1998
May 1998
April 1998
March 1998
February 1998
January 1998
December 1997
November 1997
October 1997
September 1997
August 1997
July 1997
June 1997
May 1997
April 1997
March 1997
February 1997
January 1997
December 1996
November 1996
October 1996
September 1996
August 1996
July 1996
June 1996
May 1996
April 1996
March 1996
February 1996
January 1996
December 1995
November 1995
October 1995
September 1995
August 1995
July 1995
June 1995
May 1995
April 1995

ATOM RSS1 RSS2



LIST.UVM.EDU

CataList Email List Search Powered by the LISTSERV Email List Manager