From:	IN%"BOTBML@LURE.LATROBE.EDU.AU"  "Ben Long" 16-MAY-1996 09:48:56.13

To:	IN%""


Subj:	Phototaxis in Microcystis?

Hi again all,

This is probably a question for the cyanobacterial culture people.  Does anyone

know if Microcystis spp. show phototaxis in culture?  I have a number of liquid

cultures growing in my CT room under lights.  Every morning when I come in, the

cells in each culture seem to have accumulated at one side of the flask, even

after swirling them and leaving them for a few hours.  Is this phototaxis or

just chance?  I admit I have not delved too far into Microcystis behaviour, but

does anyone know about this phenomenon or have experienced the same?

All comments welcome,



From: IN%"" "Mr Marty Saker" 16-MAY-1996 09:57:32.64 To: IN%"BOTBML@LURE.LATROBE.EDU.AU" "Ben Long" CC: Subj: phototaxis? Hi, ive noticed that Cylidrospermopsis raciborskii liquid cultures behave similarly. I have no idea why. Martin Saker James Cook University Townsville

From: IN%"" 16-MAY-1996 12:12:45.68 To: IN%"BOTBML@LURE.LATROBE.EDU.AU" "Ben Long" CC: Subj: RE: Phototaxis in Microcystis? I seem to recall a question about this a year or two ago. I notice a similar thing too but I can't say thast I have rigourously tested it. My thoughts were that it may be to do with temperature variation across the flask from variation in room circulation and/or radiative heating from lights. This could set up almost imperceptible currents in the flask that could shift the floating cells in one direction. I do not notice anything similar in cultures that are no longer buoyant. Cheers Chris ________________________________________ Christopher J. S. Bolch, Algal Geneticist/Ecologist, CSIRO Division of Fisheries, GPO Box 1538, Hobart, Tasmania, Australia, 7001. PH. 002 325314 (Aus), 061-02-325314 (Internat.) FAX. 002 325000 (Aus), 061-02-325000 (Internat.) ________________________________________

From: IN%"" "JEFF ELHAI" 17-MAY-1996 06:40:50.69 To: IN%"" CC: Subj: Phototactic Microcystis? Does any species of Microcystis show phototaxis in culture? Donat-P Haeder published a review on phototaxis that named lots of of cyanobacteria, but no Microcystis [Microbiol Rev (1987) 51:1-21]. In fact all the strains mentioned were filamentous. Waterbury et al [(1985) Science 230:74-76] published an account of a swimming unicellular strain, but no phototaxis (see also Willey & Waterbury (1989) Appl Environ Sci 55:1888-1894). So maybe not. On the other hand, Long described apparent phototactic behavior of Microcystis [(1996) Cyano-Tox 15 May 1996]. So maybe so. Jeff Elhai Department of Biological Sciences (Tel) 305-348-3584 Florida International University (Fax) 305-348-1986 University Park Campus (E-mail) Cyano@Servax.Fiu.Edu Miami FL 33199 U.S.A

From: IN%"" 17-MAY-1996 11:20:56.66 To: IN%"BOTBML@LURE.LATROBE.EDU.AU" "Ben Long" CC: Subj: RE: Phototaxis in Microcystis? I only know from my observations studying these buggers in lakes and from the writings of people such as CS Reynolds that Microcystis changes its buoyancy, generally due to changes in light. Low light increases the volume of the gas vacuoles so they can float up into the light and photosynthesize faster, high light increases the carbohydrate ballast and they sink. I've pulled a jar out from a lake I'm studying and within 20 minutes they had all floated up to the top 1 cm. Buoyancy regulation can only explain vertical motion, I can think of a means by which they could move laterally. Regards, Brad Dr. Bradford Sherman CSIRO-Centre for Environmental Mechanics GPO Box 821 Canberra, ACT 2601 Australia Internet> fax +61 6 246 5560 tel +61 6 246 5579