From: PO2::"avigad@BGUMAIL.BGU.AC.IL" 21-FEB-1995 05:18:53.71 To: Multiple recipients of list ALGAE-L CC: Subj: photosynthesis Dear friends I decided to response to Jan Conitz message through the all list in order to get your response and information if available. The instrumentation of photosynthesis measurement under field conditions has made a long way in recent years. Few portable instruments were developed employing chlorophyll fluorescence kinetics in order to estimate photosynthetic parameters and development of stress conditions in plants. The theory involved is not totally clear nevertheless no doubt this turned to be the most powerful technique available. Personally I have tested to instruments (PEA made by Hansatech and the PAM by Waltz) Vonshak, Avigad, Giuseppe Torzillo and Luisa Tomaseli. (1994) Use of Chlorophyll fluorescence to estimate the effect of photoinhibition in outdoor cultures of Spirulina platensis J. of Applied Phycology 6 31-34. The main problem is that most of the makers of the instruments are adapting it for higher plants and only few will provide the instruments with quvettes for liquid cultures. this is ofcourse not a problem for Laminaria but it is for the micro-algae. If any of you used one of the Fluorescence instruments and adapted it to be used with micro algae and cyanobacteria let me know. I have recently came across a new instrument made by PP systems looks very nice again can do for leafs and Lminaria. Have not seen it working with liquid. Does any one know more ? Looking forward for your response Avigad -------------------------------------------------------------------- Avigad Vonshak Algal Biotechnology J. Blaustein Institute for Desert Research Ben Gurion University Sede Boqer campus 84990 Israel Telephone: 7-565825; Facsimile: 7-570198; E-Mail address: avigad@BGUMAIL.BGU.AC.IL From: PO2::"HENLEY%OSUVM1.bitnet@IUBVM.UCS.INDIANA.EDU" "Bill Henley" 21-FEB-1995 12:58:52.48 To: Multiple recipients of list ALGAE-L CC: Subj: photosynthesis I have a few comments in response to Jan Conitz's request for information about photosynthesis measuring techniques and Avigad Vonshak's reply. In part the technique chosen must unfortunately depend on one's budget. The PEA and PAM fluorometers are expensive by many persons' standards: about $8,000 and $12,000+ U.S., respectively the last time I checked. Also, it is not always clear exactly what the fluorescence signals mean, although we have come a long way in the last few years in this respect. However, anytime you start to work with a new species, an extensive series of controlled laboratory experiments are advisable to relate fluorescence to photosynthesis parameters in that particular species. It is not a good idea to buy the instrument and directly start measuring under field conditions, because there are too many confounding factors. Despite the promise (see Seaton & Walker. 1990. Chlorophyll fluorescence as a measure of photosynthetic carbon assimilation. Proc. Roy. Soc. Lond. B 242:29-35.), I am not so confident yet that one can reliably predict photosytnhesis rate from fluorescence, though Fv/Fm, for example, does seem to be a reliable predictor of relative quantum efficiency. Incidentally, I think the PAM fluorometer is now available in a version that is supposed to be more amenable and sensitive to measurements of algae/phytoplankton (Walz-Heniz FAX = 49 09133 5395). As for direct measures of photosynthesis, either oxygen exchange or C-14 uptake are well-worked out methods and can be found in many references. I gave my personal opinion of guidelines that should be followed in measuring and especially interpreting photosynthesis vs. light (P-I) data in a recent review (Henley. 1993. J. Phycol. 29:729-739). I hope this can be of help or perhaps foster discussion. Bill Henley Dept. of Botany Oklahoma State Univ. Stillwater, OK 74078-0293 U.S.A. henley@vm1.ucc.okstate.edu From: PO2::"kculver@gsosun1.gso.uri.edu" "Karen Culver-Rymsza" 27-FEB-1995 14:17:10.35 To: Multiple recipients of list ALGAE-L CC: Subj: Re: photosynthesis Hello All, I was excited to see a brief discussion of photosynthesis appear here, as this is the area I am pursuing for my graduate research. A few updates may be helpful: The PAM fluorometer is available with a cuvette for algal suspensions. New mirrored cuvettes have been developed to increase sensitivity. There is still a need for a fairly thick culture (>10 ug chla/L?). This is quite a bit higher than many natural phytoplankton biomasses, so some sort of concentration would be necessary (reverse filtration?) Heinz Walz and U Schreiber, The developer of the PAM, are working on a more sensitive version that uses Xenon lamps (Sorry no ref) but I don't think it is yet available. Also there is a Pump-Probe fluorometer developed by Paul Falkowski at Brookhaven that is designed for field use on phytoplankton. It uses somewhat different principles, but still employs the Fv/Fm oncepts. Production delays have been a problem, but it is promising technology. There remain the conceptual problems of how fluorescence relates to productivity. The traditional methods (14C and O2) should still be used to substantiate fluorescence estimates. I believe (help me here) there are measurements of macroalgal PS by O2 evolution using blades isolated in jars or bags, and of course blade length increases for growth estimates. Hopefully helpful, Karen Culver-Rymsza kculver@gsosun1.gso.uri.edu From: PO3::"R.E.Warnock@BIOL.RUG.NL" "R.E.WARNOCK" 28-FEB-1995 18:01:27.43 To: Multiple recipients of list ALGAE-L CC: Subj: Photosynthesis Hi Karen, You're right, it is nice to see photosynthesis tpoics on ALGAE-L. The reference to the high sensitivity PAM fluorometer is: Schreiber U., Neubauer C. & Schliwa U. (1993) PAM fluorometer based on medium-frequency pulsed Xe-flash measuring light: A highly sensitive new tool in basic and applied photosynthesis research. Photosynthesis Research 36: 65-72. Best Wishes Roddy RODDY WARNOCK Email: WARNOCKR@BIOL.RUG.NL Tel: 31 50 632268 Biology Center - University of Groningen Fax: 31 50 635205 P.O.Box 14 - 9750 AA Haren - The Netherlands From: PO3::"avigad@BGUMAIL.BGU.AC.IL" 28-FEB-1995 18:24:51.32 To: Multiple recipients of list ALGAE-L CC: Subj: Photosynthesis Good morning Few more updates to the fluorescence and photosynthesis. 1- Fv/Fm measurements are nor enough for the photosynthetic activity estimates. Most of the new instruments will give other information as well (Y, ETR) which show better correlation with quantum yield . 2- The PAM is of no doubt the best instrument in the market. The sensitive version based on a medium frequency pulsed Xe - flash lamp can use samples of 1mg / L. (for more see Photosynthesis Research 36 pp. 65-72 1993)The mirrored cuvette is useful only when using dilute cultures. At 10mg/L the mirrored side is not effective. The main problem is the price comes to 30,000 DM F.O.B. Buy it if you have the money and need all the option it provides. I have just ordered a OS 500 PP Systems ( cost about half the price of PAM).. Promise to let you know if it is working as good as the PAM or " You get what you pay for" Have a nice day Avigad -------------------------------------------------------------------- Avigad Vonshak Algal Biotechnology J. Blaustein Institute for Desert Research Ben Gurion University Sede Boqer campus 84990 Israel Telephone: 7-565825; Facsimile: 7-570198; E-Mail address: avigad@BGUMAIL.BGU.AC.IL From: PO3::"R.E.Warnock@BIOL.RUG.NL" "R.E.WARNOCK" 28-FEB-1995 18:52:15.66 To: Multiple recipients of list ALGAE-L CC: Subj: Photosynthesis Hi Karen, You're right, it is nice to see photosynthesis topics on ALGAE-L. The reference to the high sensitivity PAM fluorometer is: Schreiber U., Neubauer C. & Schliwa U. (1993) PAM fluorometer based on medium-frequency pulsed Xe-flash measuring light: A highly sensitive new tool in basic and applied photosynthesis research. Photosynthesis Research 36: 65-72. Best Wishes Roddy RODDY WARNOCK Email: WARNOCKR@BIOL.RUG.NL Tel: 31 50 632268 Biology Center - University of Groningen Fax: 31 50 635205 P.O.Box 14 - 9750 AA Haren - The Netherlands From: PO2::"delwiche@bio.indiana.edu" 5-APR-1995 18:42:42.40 To: Multiple recipients of list ALGAE-L CC: Subj: Re: ALGAE-L: Attention physiologists! Date: Wed, 5 Apr 1995 09:21:02 +0000 Content-Type: text Is anyone aware of work that has been done or is currently in progress using C-13 instead of C-14 in photosynthetic work? Using C-14 in remote places (eg. Arctic or Antarctic) is becoming an incredible headache due to restrictions in both shipping and disposal of C-14 bicarbonate. However, stable isotope mass spectrometry has improved remarkably over the past decade, and now may offer an alternative that is affordable and environmentally more acceptable without sacrificing sensitivity or accuracy. Any thoughts on this? Thanks a lot. Ken Dunton Reply to algae-l@irlearn.ucd.ie or dunton@utmsi.zo.utexas.edu Ken - Yes, stable isotopes can be used for photosynthesis research. I have used 13C to measure the link between isoprene emission and photosynthesis in oak leaves (see references below), and have also followed the labeling of PGA and other compounds via gas chromatography/mass spectrometery (GC/MS), but have only published the work on isoprene. If you have access to a first-rate mass spectrometer you could go a long ways with these methods. The machine I was using was OK, but didn't have the sensitivity I would have liked. Unfortunately stable isotopic methods will, with some exceptions, be less sensitive than radioisotopic methods, but there are also some distinct advantages to stable isotopic methods. One key advantage is the fact that if you collect a full mass spectrum you can positively identify the molecule being studied, so there is no doubt that you are measuring labeling of the molecule of interest. You can also set the mass spectrometer to measure only a key peak, and in so doing measure a specific compound in a somewhat mixed sample. In general radiometric methods are more sensitive, but less precise than stable isotopic methods. As with any labeling method, the further you get from the Calvin Cycle the more diluite the label with be, and consequently the more dificult it will be to detect. For that reason your results will be much better if you are able to enrich the metabolite of interest. Depending upon the problem, GC/MS, LC/MS, or MS/MS (where the first mass spectrometer is used to isolate a peak, and the second instrument is used to fragment it for analysis) can be used for analyzing mixtures. These methods can also be combined. Mass spectrometers are pretty expensive instruments, but can do great things. I'm not doing physiological work any more, but Tom Sharkey has continued to work on non-radioisotopic methods in photosynthesis research, including both mass spectrometric and fluorescent/enzymatic detection methods. If you are interested in pursuing some of these techniques I would suggest that you contact him. Chuck Delwiche Delwiche, CF, and Sharkey, TD (1993). Rapid appearance of 13C in biogenic isoprene when 13CO2 is fed to intact leaves. Plant, Cell, and Environment 16:587-591. Sharkey, TD, Loreto, F and Delwiche, CF (1991). The biochemistry of isoprene emission from leaves during photosynthesis. In Trace Gas Emissions From Plants (eds. TD Sharkey, EA Holland, and HA Mooney), pp. 153-184. Academic Press, NY. -- Dr. Charles F. Delwiche -- delwiche@bio.indiana.edu Dept. of Biology, JH 142, I.U. phone: (812) 855-2549 Bloomington, IN 47405 FAX: (812) 855-6705 "Well, if you wanted to make Serac the Preparer cry, mission accomplished."