JAMES M. TIEDJE, Editor

A publicatim of thr Amrr*arr sOei#lY for MtimtiOhY
                                  ---3

Dept. Of Crop b Soil Sciences
Michigan State University
East Lansing, Mich. 43824

Area 517 353 9021

MantiptNo. AM 4%

Editaid Board Memk    Dr. J. Lederberg                                                       . .
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Kelley,Lee M. et al.,   Stereoisomeric specificity and soil gas disequilibria...

----g..--     p.6 discussion.  I don't follow why the authors are surprised to find the
    results they did.  They were empirically anticipated in ref. 5; and, theoretically,
     we have no  information  on the intensity of racemase action that would suggest that
    the rates of catabolism would be equalized thereby.   The basic interest of this paper

     ,  is in the exhibition of another, and in some respects simpler, method than in (5) for
  detecting metabolic activity of soil; and I suspect readers of Applied Microbiology
   would prefer to see a more detailed analysis of the~respective methodologies, their
  j strengths, weaknesses, and reliabilities, than this belaboring of the obvious. I do not
kndw how interested this audience will be in detailed discussions of policies for exobiological -:
research.  Surely they would like to hear more about possible applications in terrestrial
contexts, although they could readily use their  own imagination therefore.  The paper would
be of great interest, as written, for Space Life Sciences or a similar journal; for the
present vehicle, I would some thought be given to revision for the actual readership of
Applied Microbiology, which should not be difficult!          2-
        The statistical analysis on which m&h of the argument rests is not fully
explained except by reference,to a computer program not available to the reviewer. Without   3
knowing more clearly just  how the .99 confidence limits were calculated, it is not possible   r
                                                                           ~
to verify the authors' assert&s.  This may be more than needs to be in the final paper;          .
but a professional statistician should have access to theseadditional detai&s for review   R
  purposes.                              b-

     p.5 Did the authors make their own determination of the viable bacterial &ount
in the Antarctic soil sample?  Perhaps it should also be pointed out that there was surely subst f
                                                                           I-
tial proliferatioti-during the incubatio9 period.                           r)
     Fig 1.  Is there any explanation for the decresaes observed at day 5? Are they
"statistically significantW?                                70

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Further comment from a co&ague:                  9

      I would like to know more  about the gas measurements (p.3). What were the      6
     relative strengths of the sibnals?  reproducibility?  How were the gas samples      r
     transferred to the spectrometer?                                                               .

Low resolution rapid scans were used. How rapid?  Rapid scans will introduce
ion statistical errors especially in the weak signals. When were HRMS scans
necessary?  To which data do they contribute?