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Re: New work on Amphipleura pellucida

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  • rvanwezel
    Nice imagery, but I m still trying to figure out what his new findings are... René ... Findings ... Vol. ... version ... side ... don t ... anything I ... to
    Message 1 of 3 , Jun 1, 2007
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      Nice imagery, but I'm still trying to figure out what his new
      findings are...

      René

      --- In Microscope@yahoogroups.com, Gordon Couger <gordon.couger@...>
      wrote:
      >
      > Gary Gaugler's SEM Analysis Of Amphipleura pellucida with New
      Findings
      > gary <at>microtechnics.com is out in the May 2007 Microscopy Today
      Vol.
      > 15 #3 pp 12-17 and is on line on Gary's web site at
      > www.photoweb.net/micro/MT-articleR4.pdf
      > <http://www.photoweb.net/micro/MT-articleR4.pdf>. The on line
      version
      > doesn't include the cover using a pseudo color image of the concave
      side
      > of SEM image of A. pellucida. That's a shame for those of you that
      don't
      > get microscopy today.
      >
      > Gary used diatoms he got from Klaus Kemp of Microlife Services
      > www.diatoms.co.uk <http://www.diatoms.co.uk/> for his studies that
      > quantify the size and shape of A. pellucida much better than
      anything I
      > have seen before. Klaus Kemp supplies almost all the modern A.
      > pellucida slides I know of so Gary's quantification is very useful
      to
      > anyone using modern A pellucida slides.*
      >
      > *Gray's measurement and graphic description of the spacing and
      shape of
      > the pores in 3 dimensions shows why the individual pores are so
      > difficult to resolve with a visible light microscope. He also shows
      the
      > two sides of the diatom are very different as well.
      >
      > This article <http://www.photoweb.net/micro/MT-articleR4.pdf> is a
      must
      > have for anyone working with A. pellucida.
      >
      > I am trying to get my citation in BibTex format.
      > Gordon*
      > **
      >
      > *
      >
      > @article{APgg,
      > issn = {1551-9295},
      > author = {Gary Gaugler},
      > title = {SEM Analysis Of Amphipleura pellucida with New
      Findings},
      > journal = {Microscopy Today},
      > volume = {15},
      > number = {3},
      > year = {2007},
      > url = {www.photoweb.net/micro/MT-articleR4.pdf
      <http://www.photoweb.net/micro/MT-articleR4.pdf>},
      > pages = {12--17},
      > doi = {http://www.microscopy-today.com},
      > publisher = {Microscope Society of America},
      > address = {Largo Florida USA},
      > }
      >
      >
      > *
      > *
      >
    • scitech200
      Hi Rene, The published paper seems to be identical to that discussed by the group some months back with the addition of data for Mallorca A.pellucida
      Message 2 of 3 , Jun 3, 2007
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        Hi Rene,

        The published paper seems to be identical to that discussed by the
        group some months back with the addition of data for Mallorca
        A.pellucida specimens.

        I believe that these SEM images give us a detailed view of the Ap
        pores that is superior to anything previously published.

        However, I'm not real comfortable with the description of structure
        in terms of a "perpendicular orientation between pores on the
        concave (inside)and convex (outside) sides of the diatom" as
        diagrammed in Fig.10
        I have discussed an alternative description with Gary, following
        Stoermer et al (1964), as shown in a preliminary sketch:
        http://kscitech.com/MicGroup/Temp/Ap_Pores/
        The pore is the opening between the outside environment and an
        internal chamber. As I understand it, both the (outside) and
        (inside) openings are covered by membranes that give the living
        diatom a distinctive appearance:
        http://www.kscitech.com/MicGroup/Misc/Pic_103.htm
        It appears that the pore allows both ingestion of nutrients and
        expelling of waste material. The SEM image at 100Kx included in the
        above webpage clearly shows the pore-chamber structure and the
        ramifications for observation via light microscopy.

        Because of the silification process forming the pores, Gary's images
        demonstrate that they are quite irregular and vary widely in both
        form factor and dimensions over any Ap specimen. Therefore, it can
        be expected that the wide variance about mean values makes it
        difficult to easily find significant differences in structure
        between Ap specimens from different locations, for instance. Maybe a
        complete statistical analysis would uncover some reliable
        comparative information.

        Also, I'm not sure about the correlation between the reported convex
        and concave view pore measurements. There appears to be a
        discrepancy that cannot be explained by the curvature of the valve,
        but I do not have time to get back into this right now.

        Re the TEM study made by Stoermer et al (1964), Gary states
        that "their results and mine do not agree". But it's not obvious as
        to what exactly what results he is referring.

        As always, I would be interested in your comments.

        Best regards,
        Keith

        "rvanwezel" wrote:
        > Nice imagery, but I'm still trying to figure out what his new
        > findings are...

        "Gordon Couger" wrote:
        > Gary Gaugler's SEM Analysis Of Amphipleura pellucida with New
        > Findings gary <at>microtechnics.com is out in the May 2007
        > Microscopy Today Vol. 15 #3 pp 12-17 and is on line on Gary's web
        > site at www.photoweb.net/micro/MT-articleR4.pdf
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