PDF of CyanoNews Volume 11 Number 2


                     Volume 11 Number 2        July 1995


CYANONEWS - a newsletter intended to provide cyanobacteriologists with a forum

       for rapid informal communication, unavailable through journals.

       Everything you read in this newsletter is contributed by readers like

       yourself. Published occasionally, about three times per year.

SUBSCRIPTIONS - $10 or equivalent/year. (See address label for expiration

       date). No charge for electronic version.

CONTRIBUTIONS - Expected every couple of years: a new result, an upcoming

       meeting or a summary of a past meeting, a post-doctoral opening, a new

       publication, a request for strains, a change of life... something. See

       last page for addresses you can send news to.


       prominently displayed, the name of a contact person. A Directory of

       Cyanobacteriologists is distributed every two years or on request. 


COPYRIGHT - This newsletter is not copyrighted and no rights are reserved. You

       are encouraged to reproduce or to transmit any part of this publication

       by whatever means at your disposal, no permission required.





  * Collaborators sought for study of photosystem segregation and stacking

  * Spirulina biotech offer

  * "Toxic Microcystis" published

  * Request for news, comments on pigment proteins for review

  * Meetings

  * Positions sought, Positions available


  * Comings and goings of ourselves

  * David Laudenbach


  * Allen's teaching toasted

  * Foreign gene expression tamed

  * Immobilized cells' boosted NH3 output tied to glutamine synthetase


  * Meeting Report: Congress on N2 Fixation

  * Meeting report: Euro Workshop on Mol Bio






                          ****** Matters Arising ******

Dalibor Stys seeks to complement his physico-chemical expertise and resources

with genetically- or theoretically-minded COLLABORATORS to study the influence

of individual proteins from thylakoid proteins on ion and temperature induced


membranes for studies on specific and unspecific lipid-protein and

protein-protein  interactions as well as formation of membrane domains and

ion-induced interactions between membrane lamellae.

He has access to and experience with many spectroscopical techniques and is

looking for collaboration with any group that will supply him with mutants

with defined modifications of thylakoid membranes. 

   CONTACT: Dalibor Stys, Plant Cell Biology, Box 7007, 220 07 Lund,  Sweden.

      Tel: 46-46-222-3318, Fax: 46-46-222-4009,

      E-mail: Placebio-Dali@Macpost.Lu.Se or Dalibor.Stys@Placebio.Lu.Se

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L.V. Venkataraman offers to provide SPIRULINA TECHNOLOGY, on all aspects

regarding setting up plants of various capacities, including information on

product formulations.

   CONTACT: L.V. Venkataraman, "Sudarshana", #236, 8th Cross, Gokulam 3rd

      Stage, Mysore 570 002 INDIA. TEL: 821-510006, FAX: 821-512539,

      TELEX: 0846-320 POLY IN

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CRC Press has just published a new monograph entitled TOXIC MICROCYSTIS,

edited by M.F. Watanabe, K.I. Harada, W.W. Carmichael, and H. Fujiki. It

includes chapters on the ecology of Microcystis, and the chemistry and

biologically effects of its toxins. The book is 400 pages long and costs

US$189.95 (within U.S.A.) and US$228 (outside U.S.A.)

   CONTACT: CRC Press, 2000 Corporate Blvd., N.W., Boca Raton, FL 33431-9868

      U.S.A. TEL: 800-272-7737 (within U.S.A.) 407-994-0555 (outside U.S.A.)

      FAX: 800-374-3401 (within U.S.A.)

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Beverley Green is writing a REVIEW ON PIGMENT-PROTEINS for Annual Review of

Plant Physiology, to be published in 1996 and would be grateful reprints of

articles she may not have caught. She would also appreciate comments or

questions on controversial points or any other aspect. The review covers

cyanobacterial as well as plant proteins, structure determination,

macromolecular organization, and molecular evolution.

   CONTACT: Beverley R. Green, Botany Dept., University of B.C., Vancouver,

      B.C. V6T 1Z4 CANADA. TEL: 604-822-2349, FAX: 604-822-6089,

      E-MAIL: Beverley.Green@Mtsg.Ubc.Ca

                          ****** MEETINGS ******


13-18 August 1995 at North Carolina State University, Raleigh.

   CONTACT: Gerald Elkan, Department of Microbiology, North Carolina State

      University, Box 7615, Raleigh, NC 27695-7615 U.S.A., TEL: 919-515-3945

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A forum on the BIOTECHNOLOGY OF ALGAE will be held in Lake San Marcos Resort,

San Diego, California (U.S.A.) 20 Sept 1995 in conjunction with the

International Symposium on Plant DNA Preservation (17-20 Sept 1995). 

   CONTACT: E-MAIL: jonthn@aol.com

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of the formerly biannual Nordic Symposia on Toxin-producing Algae. The

Congress will be held on the Danish island of Bornholm in the Baltic on 20-24

August 1995. It is planned that the proceedings will be published.

   CONTACT: Peter Henriksen, Dept. of Phycology, Botanical Institute,

      OE. Farimagsgade 2 D, DK-1353 Copenhagen K, DENMARK. TEL: 45-35-32-22-90

      or 45-35-32-22-99, FAX: 45-35-32-23-21, E-MAIL: PHenriks@Bot.Ku.Dk

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South Africa from 16-19 April 1996. Topics include algal production systems,

photosynthesis and physiology, waste water treatment, and commercial ventures.

Registration by the deadline of 30 Nov 1995 is US$200.

   CONTACT: Johan Grobbelaar, Bloemfontein, Department of Botany and Genetics,

      University of the OFS, Bloemfontein 9300, SOUTH AFRICA. TEL: 27-51-

      4012514, FAX: 27-51-488772, E-MAIL: pjg@Rs.Uovs.Ac.Za

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Rome 27 Aug to 3 Sep 1995. The Symposium will focus on taxonomy, extreme

environments, biodiversity, cyanobacterial associations with other organisms,

and ecophysiology. Registration is 200,000 lira. Meals and hotel

accommodations start at 900,000 lira for the nine day symposium.

   CONTACT: Patrizia Albertano, Department of Biology, University of Rome `Tor

      Vergata', via della Ricerca scientifica, 00133 Rome Italy.

      TEL: 39-6-72594345, FAX: 39-6-2023500,

      E-MAIL: Albertano@Tovvx1.Ccd.Utovrm.It

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The EUROPEAN SOCIETY FOR PHOTOBIOLOGY will hold its 6th Congress in Cambridge

(Churchill College) from 2nd to 9th September 1995. The congress will have

special session on "Carotenoids in Photosynthesis and Medicine" and "Appli-

cation of protein engineering for the study of light reactions of oxygenic


   CONTACT: Paul Heelis, Faculty of Science, Health and Medical Studies, The

      North East Wales Institute, Plas Coch, Mold Road, Wrexham, Clwyd, LLI

      2AW,UK. FAX: 44 (0) 1978 290008, E-MAIL: Heelisp@Newi.Ac.Uk

                      ****** POSITIONS OFFERED ******


CONTACT: C.A. Rebeiz, Laboratory of Plant Pigment Biochemistry and

      Photobiology, 240 A, PABL, 1201 West Gregory Avenue, University of

      Illinois, Urbana IL 61801 U.S.A. TEL: 217-333-1968,

      E-MAIL: Tino@Vmd.Cso.Uiuc.Edu 

RESEARCH: Either: (1) Study of apoprotein-chlorophyll interaction during the

      biosynthesis and assembly of functional light harvesting Chl a/b protein

      (LHC II) in higher plants, or (2) Cloning the [4-vinyl]chlorophyllide

      a reductase (4VCR) gene [Biochemistry 31:8460-8464 (1992)], an enzyme

      responsible for the heterogeneity of chlorophyll biosynthesis in plants

      [Ciba Foundation symposium 180, p177-193 (1994)].

REQUIREMENTS: Some expertise in one or more of the following: porphyrin

      biochemistry, protein isolation, purification and characterization, or

      plant molecular biological techniques. For the first position,

      experience in subcellular organelle isolation, purification and

      characterization would be helpful


SEND: CV and three letters of recommendation

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CONTACT: Terry Bricker, Dept. of Microbiology, Louisiana State University,

      Baton Rouge LA 70803, U.S.A. E-MAIL: Btbric@Lsuvm.Sncc.Lsu.Edu 

RESEARCH: Structure and function relationships in photosynthesis 

SEND: CV and three letters of recommendation

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CONTACT: P. Sebban, Photosynthese Bacterienne, Bat. 24, Centre de Genetique

      Moleculaire, CNRS, 91198, Gif FRANCE. TEL: 33-1-69-82-38-26

      FAX: 33-1-69-82-35-62 E-MAIL: Sebban@Citi2.Fr

RESEARCH: Electrostatic effects and proton conduction in bacterial reaction

      center membrane proteins.

REQUIREMENTS: Well-organized and flexible candidate able to pursue a

      multidisciplinary approach. Desirable but not definitely needed is

      experience in biochemistry and spectroscopy and knowledge of molecular

      biology and genetics.

AVAILABLE: From 1 Oct 1995 for three years

SEND: CV and statement of research interests

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CONTACT: David Kramer, Institute of Biological Chemistry, Washington State

      University, Pullman WA U.S.A. TEL: 217-244-8913 or 217-333-7407, 

      E-MAIL: Kramer@Nemo.Life.Uiuc.Edu

RESEARCH: Characterization of photosynthetic electron transfer reactions in

      intact higher plants and in evolutionarily interesting algal and

      bacterial species.

REQUIREMENTS: U.S. citizenship or residence status. Experience desirable in

      one or more of following: isolation of membrane protein complexes,

      optical or electronics instrumentation, EPR spectroscopy, knowledge of

      photosynthetic or respiratory electron transfer reactions.

AVAILABLE: 1 Sept 1995

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CONTACT: H.Y. Yamamoto, University of Hawaii, 3050 Maile Way, Gilmore 202 B,

      Honolulu, HI 96822 U.S.A. E-MAIL: Yamamoto@Uhunix.Uhcc.Hawaii.Edu

RESEARCH: Molecular biology and physiological function of violaxanthin de-

      epoxidase, a key enzyme in the xanthophyll-dependent non-radiative

      energy dissipation of excess energy to down-regulate PSII photochemical


REQUIREMENTS: self-motivated individual with a strong background in molecular

      biology and publication record sought. Knowledge and interest in

      photosynthesis highly desirable. Ph.D. in plant physiology,

      biochemistry,  molecular biology, or related discipline required.

SEND: CV and names of three references

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POSITIONS OFFERED: Two post-doc openings

CONTACT: Sabeeha Merchant, Department of Chemistry and Biochemistry, UCLA, 405

      Hilgard Avenue, Los Angeles, CA 90095-1569. Tel: 310-825-8300,

      Fax: 310-206-1035, E-mail: Merchant@Chem.Ucla.Edu

RESEARCH (Position 1): Copper-responsive gene expression in the context of

      adaptation to copper-deficiency and the assembly of the photosynthetic

      apparatus [EMBO J (1991) 10:1383; EMBO J (1995) 14:857; Plant Cell


REQUIREMENTS (Position 1): Formal education and research experience in

      biochemistry, molecular biology, or genetics. 

RESEARCH (Position 2): Cytochrome biogenesis with an emphasis on the isolation

      and functional analysis of genes involved in the specification of

      cofactor (heme) -apoprotein assembly [EMBO J (1992) 11:2789; J Biol Chem

      269:5824; Mol Gen Genet (1995) 246:156].

REQUIREMENTS (Position 2): Research experience in biochemistry, molecular

      biology or genetics. 

SEND: CV, publication list, relevant reprints, and letters of recommendation 

                      ****** POSITIONS SOUGHT ******

POSITION SOUGHT: Visiting professor/scientist (for 2-3 weeks only).

CONTACT: L.V. Venkataraman, "Sudarshana", #236, 8th Cross, Gokulam 3rd Stage,

      Mysore 570 002 INDIA. TEL: 821-510006, FAX: 821-512539,

      TELEX: 0846-320 POLY IN

RESEARCH EXPERIENCE: 25 years, basic applied aspects of Spirulina effluent

      treatment, integrated systems, biotransformations, bioenergy production.

      Over 200 publications.




MASAHIRO ISHIURA, TAKAO KONDO, and the rest of the circadian rhythm team

formerly of National Institute for Basic Biology in Okazaki has moved to

Nagoya University, where they will continue studying cyanobacterial clocks.

      Department of Biology, Faculty of Science, Nagoya University, Furo-cho,

      Chikusa-ku, Nagoya, 464-01 JAPAN. Tel: 81-52-789-2495, Fax: 81-789-2963,

      E-mail: ishiura@Bio.Nagoya-U.Ac.Jp

L.V. VENKATARAMAN has taken an early retirement from the Central Food

Technological Research Institute in Mysore, India. He is keeping his academic

research alive, continuing to guide research students and consulting on

Spirulina biotechnology in India and abroad (see ANNOUNCEMENTS).

                      ****** DAVID LAUDENBACH ******

      We announce with great sadness that David Laudenbach died during surgery

on Thursday June 15, 1995 at the age of 35. It is always sad to lose a

colleague, and especially sad to lose a colleague who is so young and such an

integral part of the cyanobacterial community. 

      David received his MSc and PhD at the University of Toronto. His

research there focussed on the molecular genetic responses of Synechococcus

PCC 7942 to iron deficiency. He isolated the gene for flavodoxin and showed

that it was the second open reading frame of a dicistronic message whose

transcription was tightly regulated by iron. He demonstrated that the first

open reading frame encoded a protein with high homology to CP43, which he

correctly guessed to be the iron-stress-induced, PS II, chlorophyll-binding

protein that had been previously discovered in Lou Sherman's laboratory. He

also cloned the gene for ferredoxin and showed that its expression was not

affected by the concentration of iron in the growth medium. Before graduating

David isolated and created mutants for the genes encoding iron superoxide

dismutase and cytochrome c553. The productivity of his graduate years set a

pattern that would continue throughout the remainder of his career.

      David left Toronto to do postdoctoral research at the Carnegie

Institution for Plant Science, Stanford University. His project concerned the

acclimation of Synechococcus to sulfur deficiency. David was able to

functionally define systems involved in sulfate transport and sequence the

genes encoding the components of these systems. He also defined a novel sulfur

limitation induced gene, designated rhd, that may be involved in the

utilization of certain thiol compounds during sulfur-limited growth. Finally,

Dave discovered the regulatory gene cysR and postulated its involvement in

controlling the utilization of thiocyanate during sulfur limitation. This work

was extended to some of the highly productive projects that Dave developed

independently as an Assistant Professor at the University of Western Ontario.

      David was not the type of scientist that could be satisfied with one

project and his curiosity always got the better of him. For example, while at

Carnegie he started up collaborations with Dave Fork and Steve Herbert on the

acclimation of Synechococcus to oxidative stress and its affect on the

photosynthetic apparatus. His constant probing and 'playing' in the laboratory

provoked both new ideas and the development of new projects. David was a

talented and unique scientist.

      David is survived by his wife Lori and two children Adam (5) and Theresa

(3). A fund has been established for Adam and Theresa. If you wish to

contribute please make cheques payable to "Lori Laudenbach in trust"  and mail

them to CIBC, 228 Oxford Street East, London, Ontario N6A 1T7, Canada. Enclose

a letter stating who is making the contribution, including the names and

addresses of all for group contributions, and that the contribution is to be

directed to the trust fund for Adam and Theresa Laudenbach.

                      Arthur Grossman & Neil Straus   





      Mary Mennes Allen was honored at the 1995 meeting of the American

Society for Microbiology with the Carski Foundation Distinguished Teaching

Award, in recognition of her career in inspiring undergraduates towards a

career in science. Needless to say, a useful tool in her inspirational efforts

has been her ongoing research into the function of cyanophycin in


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      A few years ago workers at the University of Utrecht described a novel

method to facilitate the stable insertion of foreign genes into an innocuous

locus of the chromosome. The constructed chromosomal location, called PIM (for

platform for integration in metF), consists of a promoterless bla gene and

oriV, both from pBR322, a plasmid commonly used in molecular biology.

Insertion of genes of interest into that site could be achieved, with

selection for ampicillin (encoded by bla), upon recombination between the

platform and their pBR322-derived vector. Dirk Geerts now tells us that he and

others in Utrecht have extended the technique to permit inducible, high-level

expression of genes placed in the platform. The original method has further

been modified to greatly reduce the aberrant recombinational events that had

plagued the technique in the past.

      Their new vector, pTrcIS, provides a strong trc promoter whose

expression is well controlled by the lactose repressor, encoded by the lacIq

gene also on the plasmid. Downstream from this promoter is the lac operon

ribosome binding site and a polylinker to facilitate transcriptional or

translational fusions of inserted genes. Of particular utility is an NcoI site

for the insertion of the 5'end of a gene directly to the ATG start codon.

Flanking this region are a complete version of bla and oriV, required for

integration into the platform. The Utrecht group also place aadA, determining

resistance to streptomycin and spectinomycin.

      They found, using petE (encoding the precursor to plastocyanin) from

Anabaena PCC 7937 (Anabaena variabilis), and uidA (encoding beta-

glucuronidase, GUS) from E. coli, that double recombination events placing the

foreign gene into the platform occurred with a very low incidence of false

positives when streptomycin was used as the selective agent. When ampicillin

alone was used, the number of colonies recovered was much higher but the

majority of recombinants were not true double recombinants, and the frequency

with which the foreign gene was expressed in the recombinant varied from 0 to

100%, depending on the insert. Selection for streptomycin evidently ensures

that virtually all of the colonies resulting from transformation of

Synechococcus have the desired phenotype. 

      Expression of the foreign gene could be controlled within a wide dynamic

range by the addition of graded amounts of the lac inducer IPTG, with full

repression in the absence of the inducer. The highest level of induction was

36-fold, as judged by expression of GUS, or 100-fold, as judged by expression

of petE. The level of expression by the Ptrc-uidA fusion is almost 4-fold

higher than that achieved by the strongest the cyanobacterial promoter (PpetF)


      The work has recently been fully described [Geerts et al (1995)

Microbiol-UK 141:831-841].

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      Symbiotic cyanobacteria commonly release fixed nitrogen resulting from

N2 fixation to their hosts. It has long been a hope of some that cyanobacteria

could be induced to excrete ammonia on a large-scale industrial setting. In

1987, Shi Ding-Ji and others [Planta 172:298-308] reported that ammonia

excretion occurred simply by N2-fixing cyanobacteria immobilized within

polyurethane foams. Why this should be the case has been a mystery, but Shi

describes to us how Duan Xue-Yan and others at Capital Normal University and

Academia Sinica in Beijing have brought us one step closer to its solution.

      The Beijing group found that Anabaena sp. strain 2B (isolated as an

epiphyte of Azolla caroliniana) immobilized within polyurethane showed higher

(1- to 2-fold) glutamine synthetase (GS) activity than a free-living culture

over the several days following initiation of the experiment. Over the longer

term, however, GS activity in immobilized Anabaena drops 10-20% below that of

the free-living culture. This period of low GS activity roughly corresponds

to the period of high production of ammonia by immobilized Anabaena reported


      Hybridization of mRNA isolated from free and long immobilized cultures

to a probe specific for GS mRNA indicate that the drop in GS activity is due

to a corresponding decrease in GS message. In order to achieve this result,

the group had to improve upon existing methods to extract RNA from immobilized

cyanobacteria. Their modification permits efficient isolation, as judged by

comparison of stable rRNA from immobilized and free cultures.

      Details of the work have been published [Duan et al (1994) Chinese J Bot

6:102-106 (English)].   

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      The 10th International Congress on Nitrogen Fixation took place 28 May

to 3 June of this year in St. Petersburg, Russia. While the majority of

presentations concerned themselves with the doings of heterotrophic bacteria,

there were a few cyanobacterial nuggets, some of which are reported below.

      Bernd Masepohl (Bonn) reported the identification of a NOVEL REPEATED

DNA ELEMENT in Anabaena PCC 7120 with so far unknown function. This long

tandemly repeated repetitive (LTRR) sequence is 37 bp long and contains an

inverted repeat sequence. An LTRR-specific probe hybridized to numerous DNA

regions in Anabaena PCC 7120 and many other cyanobacteria. 

      In addition he described the construction of a mutant derivative of

Anabaena PCC 7120 defective in the FERREDOXIN-encoding gene, fdxH. The mutant

exhibited much reduced nitrogenase activity, confirming that this [2Fe-2S]

heterocyst ferredoxin (see B. Schrautemeier, below) is the principal electron

donor to nitrogenase, but may also partly be replaced by (an) alternate


      The mechanism of cyanobacterial NITROGENASE REGULATION OR MODIFICATION

into the inactive form of the Fe-protein is still an enigma, according to John

Gallon (Swansea). ADP-ribosylation is evidently not involved, in contrast to

the importance of such a modification in the case of glutamine synthase, as

recently reported by Noel Carr and Nick Mann.

      The mechanism of OXYGEN SENSING is now better understood in Azotobacter

vinelandii (if we may slip in a noncyanobacterium). Ray Dixon (Sussex)

described the characterization of the oxygen-sensor protein NifL. It contains

FAD with FMN as minor component and controls the catalytic activity of NifA

in the active ADP-bound form.

      The regulatory protein OxyR plays a role under OXIDATIVE STRESS in

E. coli and Salmonella typhimurium. Karin Jaeger (Hannover) found an OxyR-like

protein in Anabaena variabilis and Anabaena PCC 7120 by using a specific

antibody against the E. coli protein. Southern blot analyses with the E.coli

gene probe reveled no signal with cyanobacterial genomic DNAs.

      Bernhard Schrautemeier (Bonn) reported on DUAL MO-NIF SYSTEMS expressed

from separate nif gene clusters (nif1, nif2) of Anabaena variabilis ATCC 29413

that also were independently discovered by Teresa Thiel and coworkers in St.

Louis. Teresa, using a lacZ reporter system with a fluorescent substrate,

conclusively demonstrated localized expression of nif1 (only in heterocysts)

versus nif2 (in all vegetative cells), Bernhard's approach emphasizes the time

component/differential kinetics of oxygen-controlled nif2- versus

developmentally controlled nif1-expression after nitrogen deprivation: Nif2

is expressed only under strictly anaerobic conditions as early as 1-2 hours

after nitrogen stepdown -- long before the appearance of proheterocysts. In

contrast, Nif1 is expressed only after (pro)heterocysts have appeared, i. e.

not earlier than about 10 hours after nitrogen depletion, irrespective of

anaerobic or aerobic growth conditions. By using a standardized comparative

induction assay monitoring nitrogenase activity during the 20 hours following

nitrogen deprivation, he additionally demonstrated that Anabaena PCC 7120 has

no characteristics of a functional Nif2 system.

      Examining the region upstream from each nifHDK cluster, Bernhard hit

upon different genes encoding ferredoxins: fdxH1 and fdxH2 for the nif1 and

nif2 clusters, respectively. It is interesting that FdxH1 is oxygen-tolerant

in vitro, while FdxH2 is rapidly inactivated by oxygen. Both are equally

effective in donating electrons to nitrogenase isolated from heterocysts. The

fdxH2 gene, but not fdxH1, is followed by a gene, fdxB, encoding a second

ferredoxin of unknown function, as also present downstream of fdxH from the

nonheterocystous filamentous Plectonema PCC 73110. Hence the Nif2 system is

homologous to the single, environmentally regulated Mo-Nif system expressed

in all cells of nonheterocystous filamentous species [Smoker et al (1990) Meth

Molec Cell Biol 2:59-65].

      Many additional questions now arise from the work of Bernhard, Teresa,

and coworkers. In particular: (a) How do nif1 and nif2 differ in their

regulatory mechanisms yet intersect in their dependence on nitrogen

deprivation? (b) What is the distribution of the two systems amongst nitrogen-

fixing cyanobacteria? (c) What is the benefit of two coexisting nif systems?

                              -- Karin Jaeger

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                ****** BIOENERGETICS AND PHYSIOLOGY ******

      Several presentations related to the structure and function of

FERREDOXIN-DEPENDENT ENZYMES. Data from Herbert Boehme's group in Bonn

suggests a common but not identical ferredoxin binding domain on the

ferredoxin-dependent enzymes nitrate reductase, nitrite reductase and

ferredoxin NADP-reductase (FNR). It is noteworthy that the same mutations in

specific amino acids of ferredoxin that stimulated the reversed flow from

NADPH-reduced FNR to oxidized ferredoxin also severely inhibited electron

transport from reduced ferredoxin to FNR. Carlos Gomez-Moreno (Zaragoza)

presented rapid kinetic characterizations of ferredoxin, flavodoxin and FNR

mutants in which amino acids involved in the interaction between these

proteins had been modified. Two others from Zaragoza, Maria Fillat and Marisa

Peleato, described, respectively: (1) the overexpression in a

protease-deficient E. coli of the 49-kDa form of FNR (the complete product of

petH) from Anabaena and (2) the characterization of different

FNR-phycobiliprotein complexes of Anabaena, isolated from vegetative cells and


      CAROTENOID BIOSYNTHESIS was the focus of presentations by Gerhard

Sandmann (Frankfurt) and Blanca Fernandez (Sevilla). Sandmann reported the

cloning of the zeta-carotene desaturase gene from Anabaena PCC 7120 by

heterologous complementation. Fernandez, using the cat gene as a reporter,

showed stimulation of the expression of the phytoene desaturase (crtP)

promoter at high light intensities, a result in agreement with the

photoprotective role ascribed to carotenes.

      The molecular bases of the ADAPTIVE RESPONSES of cyanobacteria to

changes in light conditions were addressed by a few presentations. Jean

Houmard (Paris) reported that whereas changes in the photosynthetic photon

flux density exerts a major influence on the differential expression of genes

within the psbA and psbD multigene families, changes in light wavelength also

result in profound modifications of the light harvesting apparatus, in those

strains that exhibit chromatic adaptation. In Calothrix PCC 7601, different

phosphorylated DNA-binding proteins, namely RcaA and B (which specifically

bind to the promoter region of the phycoerythrin operon) and RcaD (which binds

to the phycocyanin-2 operon), are expressed under green-light and red-light,

respectively. However, no difference was found in the subunit composition of

the RNA polymerase isolated from cells grown under the two conditions.

      Insights into the LIGHT REGULATION of the PSBA GENE FAMILY (encoding D1

protein) in Synechocystis PCC 6803 were provided by Christer Jansson

(Stockholm) and David Campbell (Umea). Jansson found that psbA2 and psbA3, two

gene copies differing in their promoter elements, were light-regulated and

transcribed at vastly different levels (30-fold higher for psbA2).

Inactivation of psbA2 by in vitro mutagenesis led to an 8-fold up regulation

of psbA3 gene transcription. Site-specific mutagenesis permitted the

identification of putative Mn-binding amino acids within D1 and sequences

involved in the light-triggered proteolytic degradation of this protein.

Campbell reported that Synechococcus responds to excitation stress by

replacing the constitutive form of the D1 protein (D1:1) by another form,

D1:2, that confers increased resistance to photoinhibitory damage and a higher

photochemical efficiency of PS II. This D1 exchange is a response to excess

excitation of photosynthetic electron transport, and not a specific response

to light intensity per se. 

      Aaron Kaplan (Jerusalem) described novel HIGH-CO2-REQUIRING MUTANTS of

Synechococcus PCC 7942. These mutants were obtained upon integration of

plasmids containing DNA internal to the CO2-related operons, selected from a

library composed by short genomic fragments. The mutant-forming plasmids were

retrieved and their genomic regions used as probes of wild-type transcripts

and genomic DNA. By this means, Kaplan's group showed that the different

regions are transcribed and do not lie in close proximity to each other in the

chromosome. The study by fusion experiments of the promoter regions of genes

modulated by changing CO2 concentration indicated the presence of enhancing

and repressing elements. Conserved sequences were found in the promoter region

of several CO2-responding genes. Francoise Joset's group (Marseille) described

the characterization of a gene from Synechocystis PCC 6803, hatR, involved in

a high affinity system of HCO3- uptake and the identification of proteins

showing different levels of synthesis in response to changes in the levels of

inorganic carbon.

      Aurelio Serrano (Sevilla) cloned the NAD(P)-dependent GLYCERALDEHYDE

3-PHOSPHATE DEHYDROGENASE (G3P DHase) from Synechocystis PCC 6803, by

complementation of an E. coli gap- mutant with a genomic library. The enzyme

restored the glycolytic pathway in E.coli, and thus may be presumed able to

function in that capacity in Synechocystis as well. Since G3P DHase is already

known to be essential in the reductive  pentose phosphate pathway, the enzyme

may therefore play both anabolic and catabolic roles in Synechocystis. The

sequence of the complementing gene predicted a protein very similar (70-80%

identity) to G3P DHase from chloroplasts of higher plants. Southern blots

using as probes the cloned G3P DHase genes of Synechocystis and E. coli

indicated that two genes, one corresponding to each type, are present in the

Synechocystis genome. However, since immunological and biochemical data are

consistent with the presence in Synechocystis, of only an NAD(P)-dependent

enzyme, Serrano suggested that the E. coli-like gene may be a pseudogene or

a gene not expressed under normal culture conditions. 

      Two presentations had important implications regarding cyanobacterial

RESPIRATION. Georg Schmetterer (of Vienna) obtained cox- mutants of

Synechocystis PCC 6803 in which the three genes coding for the terminal

oxidase of aa3 type were inactivated. Surprisingly, although no cytochrome c

oxidation by membranes of the mutants was observed, the intact cells respire

almost normally. Schmetterer explained these results by postulating the

existence of An "alternative terminal oxidase", sensitive to KCN, that reduces

O2 in the dark with NAD(P)H. Gunther Peschek (Vienna) presented results

indicating that the cyanobacterial cytochrome c oxidase might be subject to

adenylate regulation. A putative mitochondria-like subunit IV gene (ctaIV) was

identified in Synechocystis exhibiting consensus sequences of

adenylate-binding enzymes.

      Norio Murata (Okazaki) described very interesting results on the GENETIC

MANIPULATION OF MEMBRANE LIPIDS in cyanobacteria. His group was able both to

decrease the degree of unsaturation of fatty acids in Synechocystis PCC 6803

(by inactivating the corresponding desaturase genes) and to increase the

degree of unsaturation of fatty acids in membranes of Synechococcus PCC 7942

(by transformation with foreign cyanobacterial desaturase genes). These

changes did not affect rates of photosynthesis and photosynthetic electron

transport and only scarcely affected heat stability of oxygen evolution.

However, a lower degree of unsaturation enhanced photoinhibition at low

temperatures and a higher degree of unsaturation accelerated recovery from

photoinhibition. These results may help to elucidate the mechanisms of

photoprotection of photosynthetic organisms at low temperatures.

                            -- Aurelio Serrano


      Antonia Herrero and Ignacio Luque (both of Sevilla) reported results

concerning the mechanism of GENE REPRESSION BY AMMONIA in Synechococcus

PCC 7942. They found that mutant strains that express NtcA to a high and

constitutive level still require the absence of ammonium to express

NtcA-regulated genes (e.g. nir operon, glnA). They suggested that a

coactivator may be required for the expression of nitrogen-regulated genes or

that NtcA protein is posttranscriptionally interconverted between an active

and an inactive form in response to the nitrogen status. Antonia also proposed

that the level of NtcA might contribute to the differential regulation of some

genes through weak binding of the protein to sites deviating from the known

NtcA consensus binding site.

      Jose Frias (Sevilla) discussed the GENES OF NITRATE assimilation: their

regulation and function. The nir-nrtABCD-narB gene cluster (the nir operon)

of Anabaena PCC 7120 was cloned and analyzed. Northern analysis showed that

the nir operon is transcribed in the absence of ammonium with or without

nitrate or nitrite in the medium, this despite the fact that high levels of

nitrate and nitrite reductase activities occur only in the former case. A 460

bp leader sequence between the Ntc-regulated promoter and the first codon of

nir seems to lack any function: when removed no change in phenotype was

observed. Insertional inactivation of nrtA resulted in mutants that were

unable to transport nitrate at low external concentration (0.1 mM), but at

high concentration (18 mM) nitrate  was taken up at a slow rate and reduced

to ammonium. High activities of the nitrate assimilation enzymes were observed

at either level of nitrate concentrations but neither could repress heterocyst


      Paco Navarro (Sevilla) found two different genes, gltS and gltB, in

Synechocystis PCC 6803, that encode ferredoxin-dependent GLUTAMATE SYNTHASES

(GOGAT). Inactivation of either one did not significantly impair growth

(concomitant inactivation of both has not yet been tried). While gltS was

present in many other cyanobacteria tested, gltB was additionally found only

in Pseudoanabaena PCC 6903. Both enzymes expressed in E. coli accept electrons

from PetF-type ferredoxins, but flavodoxin was inactive. Interestingly, GltB

was equally active with heterocyst ferredoxin (FdxH). Figueroa (Sevilla)

cloned gltS from Anabaena PCC 7120. GltS activity was highest in crude

extracts of cells using N2 as the nitrogen source, as opposed to nitrate or

ammonium, hinting at a role for this GOGAT in heterocyst metabolism.

      Reyes and Florencio (Sevilla) reported that the REDOX STATE controls the

transcription of glnA, encoding GLUTAMINE SYNTHETASE (GS). Transcript

abundance was high when Synechocystis PCC 6803 was grown in the light or in

the dark with glucose and low in the dark without glucose or when DCMU (a

PSII-inhibitor) or DBMIB (a cytochrome b6/f complex-inhibitor) was added.

N-starvation provoked a delay in decrease of glnA transcripts suggesting a

connection between nitrogen and redox controls of transcript levels. Crespo

(Sevilla) found that redox control seems also to govern inactivation of

glutamine synthetase (GSI) in vivo. In this case, however, the addition of

DBMIB, leading to a reduced plastoquinone (PQ) pool, was not inhibitory. This

result suggests that the redox state of PQ or a component of the b6/f-complex

is a signal for modification.

      The same group also characterized a SECOND TYPE OF GLUTAMINE SYNTHETASE

from Synechocystis PCC 6803, encoded by glnN, similar to the GSIII-type

enzymes found in the Bacteriodaceae. GlnN has a larger subunit size (75kD)

than the 50kD product of glnA and, unlike the dodecameric GlnA, probably

exists in its native state as a hexamer. According to Western blot analysis,

GSIII is more abundant in PCC 6803 and other non nitrogen-fixing cyanobacteria

when they are starved for nitrogen. GSIII is lacking, however, in N2-fixing

Anabaena PCC 7120.

      Nicole Tandeau de Marsac and coworkers (Paris) described PII PROTEIN as

the central node for the coordination of nitrogen and carbon assimilation in

cyanobacteria. PII is a protein whose homologue in enteric bacteria is

involved in regulation of GS activity and Ntr-regulated gene expression. She

reported that a PII-deficient mutant of Synechococcus PCC 7942 can take up

nitrate even in the normally inhibitory presence of ammonium. The mutant has

also lost the ability to adapt rapidly to changes in light, nitrogen, and

carbon supplies. PII thus functions to integrate nutritional stimuli and to

reestablish a proper C/N-ratio for balanced cell growth. In Calothrix

PCC 7504, PII is found to be unmodified during the hormogonial stage of

growth, whereas PII modification is most pronounced under conditions of

heterocyst differentiation. Thus, in filamentous strains PII may be

additionally involved in cell differentiation processes.

      Karl Forchhammer (Munich) devised an in vitro test for PHOSPHORYLATION

OF PII that clearly demonstrated that 2-ketoglutarate is sufficient to

activate PII kinase from Synechococcus PCC 7942. No other compound tested

(e.g., glutamine or other amino acids) could substitute or counteract the

stimulation by 2-ketoglutarate. The latter may serve as an intracellular

signal to monitor the balance of assimilated carbon and nitrogen that is

sensed by PII kinase and transmitted to PII by protein serine phosphorylation.

      Lucas Stal (Amsterdam) made an interesting observation related to the


the light. He noted that a Cyanothece strain is impaired in nitrogen fixation

when grown in batch cultures, where they produce sulfated extracellular

polysaccharides and thus rapidly deplete the medium of sulfate. In continuous

cultures with a continuous supply of sulfate nitrogenase activity was high and

confined predominantly to the light. The same was true when sulfate was added

to a sulfate-depleted batch culture. This intriguing observation leaves us

once more perplexed (as with the case of Trichodesmium): how do they do it

without heterocysts?

                         -- Bernhard Schrautemeier

                           ****** ECOLOGY ******

        One perennial problem for ecologists is that of IDENTIFYING the

ORGANISMS present in natural populations.  Strain identification is also a

problem for those of us working on newly isolated strains.  A variety of

molecular techniques are available for strain identification and

discrimination; the results presented on three posters (Anneliese Ernst,

Konstanz; Gary Barker, Bristol; Suzzanne McColl, Liverpool) lend yet more

evidence to what has been long suspected, namely that natural populations of

cyanobacteria consist of many distinct clones.

        The biology of GAS VACUOLATE CYANOBACTERIA was covered in two

presentations.  The advantages accruing from gas vesicle production by

Aphanizomenon in the Baltic Sea is being quantified by Walsby and co-workers

(Bristol); such colonial forms can gain a 3-fold photosynthetic advantage over

their non-buoyant competitors by rapidly moving back towards surface, and

light, after mixing-events. The genes involved in producing gas vesicles and

the interactions between the gene products were described by Hayes et al. Once

thought to be a simple structure formed by self assembly of a single type of

protein, it is now clear that it takes the concerted action of at least six

different gene products to assemble these structures.

        Elke Dittmann et al. (Berlin) described progress toward the complete

characterization of the genes encoding PEPTIDE SYNTHETASES of cyanobacteria. 

These incredibly complex enzymes are responsible for the synthesis of the

cyclic peptide toxins. The group in Berlin have partially characterized a gene

from Microcystis aeruginosa using conserved domains from peptide synthetases

to provide probes. This approach is similar to that described by Leo

Rouhiainen et al. (Helsinki) in Urbino for the genes from Nodularia. With the

genes available from a number of organisms it should now be possible to study

the biological role of these toxic compounds.

        Molecular mechanisms of SALT TOLERANCE were described in two

presentations (Martin Hagemann and Ellen Zuther, Rostok).  A total of 18 salt

sensitive mutants of Synechocystis PCC 6803 were produced by random cartridge

mutagenesis; 9 of these were unable to synthesize glucosylglycerol. One of the

genes identified, stpA, had been previously characterized (Francoise Joset,

Marseille).  Three other ORFs have been characterized in Rostock; the role of

theses genes has yet to be confirmed but glucosylglycerol transport and

positive regulation of glucosylglycerol synthesis seem likely candidates.

        Nigel Robinson (Newcastle) gave a lucid summary of work carried out

in his laboratory on the regulation of expression of the METALLOTHIONINE-

ENCODING GENE smtA from Synechococcus PCC 7942.  SmtB is a repressor of smtA

expression that dissociates from the smtA promoter in the presence of Zn2+.

Upstream of smtB is smtZ, a gene that encodes a protein the C-terminal end of

which has the features of a zinc-finger: SmtZ may up-regulate smtA expression

in the presence of Zn2+.  Upstream again is dnaG, encoding primase which could

be a zinc metalloprotein.  An octameric palindrome HIP1 (5'- GCGATCGC-3') is

involved in the deletion of smtB in cells selected for zinc tolerance.  This

sequence occurs at much higher than expected frequencies in many cyanobacteria

(but not in any of the marine isolates investigated); is it involved in genome

plasticity?  We will have to wait for the answer to that question.

        All of the presentations at the meeting were excellent and I wish I

had the time to write about them all (in particular Nick Mann, Warwick, gave

a first class talk of extreme ecological relevance, but mine came straight

afterwards so I missed most of what he saying) but at least you now have the

gist of some of the topics covered. 

                               - Paul Hayes




                    ****** EVOLUTION and ECOLOGY ******

Neilan BA (1995). Identification and phylogenetic analysis of toxigenic

      cyanobacteria by multiplex randomly amplified polymorphic DNA PCR. Appl

      Environ Microbiol 61:2286-2291

Nimura K, Yoshikawa H, Takahashi H (1994). Sequence analysis of the third dnaK

      homolog gene in Synechococcus sp PCC 7942. Biochem Biophys Res Commun

      205:2016-2017 (Correction to Vol 201, pg 848, 1994)

Sanangelantoni AM, Tiboni O (1993). The chromosomal location of genes for

      elongation factor Tu and ribosomal protein S10 in the cyanobacterium

      Spirulina platensis provides clues to the ancestral organization of the

      str and S10 operons in prokaryotes. J Gen Microbiol 139:2579-2584

Shimada A, Kanai S, Maruyama T (1995). Partial sequence of ribulose-1,5-

      bisphosphate carboxylase/oxygenase and the phylogeny of Prochloron and

      Prochlorococcus (Prochlorales). J Mol Evol 40:671-677

Budel B, Luttge U, Stelzer R, Huber O, Medina E (1994). Cyanobacteria of rocks

      and soils of the Orinoco lowlands and the Guayana uplands, Venezuela.

      Bot Acta 107:422-431

Caumette P, Matheron R, Raymond N, Relexans J-C (1994). Microbial mats in the

      hypersaline ponds of Mediterranean salterns (Salins-de-Giraud, France).

      FEMS Microbiol Ecol 13:273-286

Howarth RW, Butler T, Lunde K, Swaney D, Chu CR (1993). Turbulence and

      planktonic nitrogen fixation: A mesocosm experiment. Limnol Oceanogr


Kevbrin VV, Kostrikina NA, Lysenko AM (1994). Isolation and identification of

      Pseudomonas nautica, a heterotrophic satellite of Microcoleus

      chthonoplastes cyanobacteria. Microbiol-Engl Tr 63:607-612

Kraus MP, Gorsuch JW, Lower WR (1991) Cyanophage/host assay for toxicity

      assessment in water, wastewater, sludges, and composts. In: Lewis MA,

      Wang W (eds) Plants for Toxicity Assessment, vol 2. American Society for

      Testing and Materials, Philadelphia, PA (U.S.A.). pp.383-391

Lassen C, Jorgensen BB (1994). A fiber-optic irradiance microsensor (cosine

      collector): Application for in situ measurements of absorption

      coefficients in sediments and microbial mats. FEMS Microbiol Ecol


Luttge U, Budel B, Ball E, Strube F, Weber P (1995). Photosynthesis of

      terrestrial cyanobacteria under light and desiccation stress as

      expressed by chlorophyll fluorescence and gas exchange. J Exp Bot


Mishra SR, Saksena DN (1993). Planktonic flora of textile mill waste water

      from Birla Nagar industrial complex at Gwalior, Madhya Pradesh. Comp

      Physiol Ecol 18:124-126

Moller A, Norrby AM, Gustafsson K, Jansson J (1995). Luminometry and PCR-based

      monitoring of gene-tagged cyanobacteria in Baltic Sea microcosms. FEMS

      Microbiol Lett 129:43-49

Neale PJ, Priscu JC (1995). The photosynthetic apparatus of phytoplankton from

      a perennially ice-covered Antarctic lake: Acclimation to an extreme

      shade environment. Plant Cell Physiol 36:253-263

Sellner KG, Brownlee DC, Bundy MH, Brownlee SG, Braun KR (1993). Zooplankton

      grazing in a Potomac River cyanobacteria bloom. Estuaries 16:859-872

Singh NK (1993). Studies on density, productivity and species composition of

      phytoplankton in relation to abiotic spectrum of the Ganges at

      Sahibganj. J Freshwat Biol 5:1-8

Soto Y, Bianchi M, Martinez J, Rego JV (1993). Seasonal evolution of

      microplanktonic communities in the estuarine front ecosystem of the

      Rhone River plume (North-western Mediterranean Sea). Estuar Coast Shelf

      Sci 37:1-13

Srivastava AK, Renu (1988). Physico-chemical and biological characteristics

      of a sugar factory effluent. Indian J Ecol 15:192-193

Vaulot D, Marie D, Olson RJ, Chisholm SW (1995). Growth of Prochlorococcus,

      a photosynthetic prokaryote, in the equatorial Pacific Ocean. Science


Wood MD, Oliver RL (1995). Fluorescence transients in response to nutrient

      enrichment of nitrogen- and phosphorus-limited Microcystis aeruginosa

      cultures and natural phytoplankton populations: A measure of nutrient

      limitation. Aust J Plant Physiol 22:331-340

                          ****** SYMBIOSIS ******

Baulina OI, Yagodina IB, Korzhenevskaya TG, Gusev MV (1994). Morphology and

      ultrastructure of cyanobacterium Synechococcus elongatus grown in

      association with plant cells. Microbiol-Engl Tr 63:365-372

Caudales R, Wells JM, Antoine AD, Butterfield JE (1995). Fatty acid

      composition of symbiotic cyanobacteria from different host plant

      (Azolla) species: Evidence for coevolution of host and symbiont. Int J

      Syst Bact 45:364-370

Cohen MF, Wallis JG, Campbell EL, Meeks JC (1994). Transposon mutagenesis of

      Nostoc sp strain ATCC 29133, a filamentous cyanobacterium with multiple

      cellular differentiation alternatives. Microbiol UK 140:3233-3240

Gantar M, Kerby NW, Rowell P, Obreht Z, Scrimgeour C (1995). Colonization  

      of  wheat (Triticum  vulgare L.) by N2-fixing cyanobacteria: IV. Dark

      nitrogenase activity and effects of cyanobacteria on natural 15N

      abundance in plants. New Phytol 129:337-343

Rasmussen U, Johansson C, Bergman B (1994). Early communication in the

      Gunnera-Nostoc symbiosis: Plant-induced cell differentiation and protein

      synthesis in the cyanobacterium. Mol Plant Microbe Interaction 7:696-702

Schussler A, Schnepf E, Mollenhauer D, Kluge M (1995). The fungal bladders of

      the endocyanosis Geosiphon pyriforme, a Glomus-related fungus: Cell wall

      permeability indicates a limiting pore radius of only 0.5 nm.

      Protoplasma 185:131-139

Uheda E, Kitoh S, Dohmaru T, Shiomi N (1995). Isolation and analysis of gas

      bubbles in the cavities of Azolla leaves. Physiol Plant 93:1-4

                ****** TOXINS and NATURAL SUBSTANCES ******

Cardellina JH II, Munro MHG, Fuller RW, Manfredi KP, McKee TC, Tischler M,

      Bokesch HR, Gustafson KR, Beutler JA, Boyd MR (1993). A chemical

      screening strategy for the dereplication and prioritization of HIV-

      inhibitory aqueous natural products extracts. J Nat Prod (Lloydia)


Echavarren AM, Castano AM (1995). Synthesis of 3-methylaspartic acids by ring-

      contraction of a nickelacycle derived from glutamic anhydride.

      Tetrahedron 51:2369-2378

Harada K, Fujii K, Shimada T, Suzuki M, Sano H, Adachi K, Carmichael WW

      (1995). Two cyclic peptides, anabaenopeptins, a third group of bioactive

      compounds from the cyanobacterium Anabaena flos-aquae NRC 525-17.

      Tetrahedron Lett 36:1511-1514

Horner RA, Postel JR (1993). Toxic diatoms in western Washington waters (U.S.

      West Coast). Hydrobiol 269-270:197-205

Ikawa M, Sasner JJ, Haney JF, Foxall TL (1995). Pterins of the cyanobacterium

      Aphanizomenon flos-aquae. Phytochemistry 38:1229-1232

Ishida K, Murakami M, Matsuda H, Yamaguchi K (1995). Micropeptin 90, a plasmin

      and trypsin inhibitor from the blue-green alga Microcystis aeruginosa

      (NIES-90). Tetrahedron Lett 36:3535-3538

Jefford CW, McNulty J (1994). A practical synthesis of (2S,3R)-3-amino-2-

      methylpentanoic acid from L-aspartic acid. Helv Chim Acta 77:2142-2146

Jones GJ, Orr PT (1994). Release and degradation of microcystin following

      algicide treatment of a Microcystis aeruginosa bloom in a recreational

      lake, as determined by HPLC and protein phosphatase inhibition assay.

      Water Res 28:871-876

Kos P, Gorzo G, Suranyi G, Borbely G (1995). Simple and efficient method for

      isolation and measurement of cyanobacterial hepatotoxins by plant tests

      (Sinapis alba L). Anal Biochem 225:49-53

Lee ESJ, Gleason FK (1994). A second algicidal natural product from the

      cyanobacterium, Scytonema hofmanni. Plant Sci 103:155-160

Menges M, Bruckner R (1995). Enantioselective synthesis of bis(gamma-

      butyrolactones). Their oxidative degradation to tetraols as a key step

      in stereoselective syntheses of 1,3,5,7,9-pentaol synthons for

      polyhydroxylated natural products. Liebigs Annalen:365-384

Murata H, Shoji H, Oshikata M, Harada KI, Suzuki M, Kondo F, Goto H (1995).

      High-performance liquid chromatography with chemiluminescence detection

      of derivatized microcystins. J Chromatogr A 693:263-270

Nagle DG, Geralds RS, Yoo HD, Gerwick WH, Kim TS, Nambu M, White JD (1995).

      Absolute configuration of curacin A, a novel antimitotic agent from the

      tropical marine cyanobacterium Lyngbya majuscula. Tetrahedron Lett


Nagle DG, Gerwick WH (1995). Nakienones A-C and nakitriol, new cytotoxic

      cyclic C-11 metabolites from an Okinawan cyanobacterial (Synechocystis

      sp) overgrowth of coral. Tetrahedron Lett 36:849-852

Nicholson BC, Rositano J, Burch MD (1994). Destruction of cyanobacterial

      peptide hepatotoxins by chlorine and chloramine. Water Res 28:1297-1303

Park H-D, Watanabe MF, Harada KI, Nagai H, Suzuki M, Watanabe M, Hayashi H

      (1993). Hepatotoxin (microcystin) and neurotoxin (anatoxin-a) contained

      in natural blooms and strains of cyanobacteria from Japanese

      freshwaters. nat toxins 1:353-360

Rapala J, Lahti K, Sivonen K, Niemela SI (1994). Biodegradability and

      adsorption on lake sediments of cyanobacterial hepatotoxins and

      anatoxin-a. Lett Appl Microbiol 19:423-428

Rinehart KL, Namikoshi M, Choi BW (1994). Structure and biosynthesis of toxins

      from blue-green algae (cyanobacteria). J Appl Phycol 6:159-176

Shi L, Carmichael WW, Miller I (1995). Immuno-gold localization of

      hepatotoxins in cyanobacterial cells. Arch Microbiol 163:7-15

Stratmann K, Burgoyne DL, Moore RE, Patterson GML, Smith CD (1994). Hapalosin,

      a cyanobacterial cyclic depsipeptide with multidrug-resistance reversing

      activity. J Org Chem 59:7219-7226

Stratmann T, Burgoyne DL, Moore RE, Patterson GML, Smith CD (1995). Hapalosin,

      a cyanobacterial cyclic depsipeptide with multidrug-resistance reversing

      activity (vol 59, pg 7222, 1994). J Org Chem 60:2950

Utkilen H, Gjolme N (1995). Iron-stimulated toxin production in Microcystis

      aeruginosa. Appl Environ Microbiol 61:797-800

White JD, Kim TS, Nambu M (1995). Synthesis of curacin A: A powerful

      antimitotic from the cyanobacterium Lyngbya majuscula. J Am Chem Soc


    ****** TOXINS and NATURAL SUBSTANCES (Physiological Effects) ******

An JS, Carmichael WW (1994). Use of a colorimetric protein phosphatase

      inhibition assay and enzyme linked immunosorbent assay for the study of

      microcystins and nodularins. Toxicon 32:1495-1507

Claeyssens S, Francois A, Chedeville A, Lavoinne A (1995). Microcystin-LR

      induced an inhibition of protein synthesis in isolated rat hepatocytes.

      Biochem J 306:693-696

Elsaadi O, Esterman AJ, Cameron S, Roder DM (1995). Murray River water, raised

      cyanobacterial cell counts, and gastrointestinal and dermatological

      symptoms. Med J Aust 162:122-125

English WR, Schwedler TE, Dyck LA (1993). Aphanizomenon flos-aquae, a toxic

      blue-green alga in commercial channel catfish, Ictalurus punctatus,

      ponds: A case history. J Appl Aquacult 3:195-209

Golowasch J, Paupardintritsch D, Gerschenfeld HM (1995). Enhancement by

      muscarinic agonists of a high voltage-activated Ca2+ current via

      phosphorylation in a snail neuron. J Physiol-London 485:21-28

Hamel E, Blokhin AV, Nagle DG, Yoo HD, Gerwick WH (1995). Limitations in the

      use of tubulin polymerization assays as a screen for the identification

      of new antimitotic agents: The potent marine natural product curacin A

      as an example. Drug Develop Res 34:110-120

Hayakawa K, Kohama K (1995). Reversible effects of okadaic acid and

      microcystin-LR on the ATP-dependent interaction between actin and

      myosin. J Biochem Tokyo 117:509-514

Hori K, Ishibashi G, Okita T (1994). Hypocholesterolemic effect of blue-green

      alga, ishikurage (Nostoc commune) in rats fed atherogenic diet. Plant

      Foods Hum Nutr 45:63-70

Kiviranta J, Abdel-Hameed A (1994). Toxicity of the blue-green alga

      Oscillatoria agardhii to the mosquito Aedes aegypti and the shrimp

      Artemia salina. World J Microbiol Biotechnol 10:517-520

Lahitova N, Doupovcova M, Zvonar J, Chandoga J, Hocman G (1994). Antimutagenic

      properties of fresh-water blue-green algae. Folia Microbiol Prague


Murphy J, Crompton CM, Hainey S, Codd GA, Hutchison CJ (1995). The rote of

      protein phosphorylation in the assembly of a replication competent

      nucleus: Investigations in Xenopus egg extracts using the cyanobacterial

      toxin microcystin-LR. J Cell Sci 108:235-244

Ohta T, Sueoka E, Iida N, Komori A, Suganuma M, Nishiwaki R, Tatematsu M, Kim

      SJ, Carmichael WW, Fujiki H (1994). Nodularin, a potent inhibitor of

      protein phosphatases 1 and 2A, is a new environmental carcinogen in male

      F344 rat liver. Cancer Res 54:6402-6406 

Papadogiannakis N (1995). (-)-Indolactam V-induced mitogenesis in human fetal

      neonatal and adult T cells: Lower response of neonatal cells and

      possible regulatory role of monocytes in protein kinase C-mediated

      pathways. Cell Immunol 162:288-294

Pennings SC, Paul VJ (1993). Secondary chemistry does not limit dietary range

      of the specialist sea hare Stylocheilus longicauda (Quoy et Gaimard

      1824). J Exp Mar Biol Ecol 174:97-113

Runnegar MT, Kong SM, Zhong YZ, Lu SC (1995). Inhibition of reduced

      glutathione synthesis by cyanobacterial alkaloid cylindrospermopsin in

      cultured rat hepatocytes. Biochem Pharmacol 49:219-225

Takai A, Sasaki K, Nagai H, Mieskes G, Isobe M, Isono K, Yasumoto T (1995).

      Inhibition of specific binding of okadaic acid to protein phosphatase

      2A by microcystin-LR, calyculin-A and tautomycin: Method of analysis of

      interactions of tight-binding ligands with target protein. Biochem J


Williams DE, Kent ML, Andersen RJ, Klix H, Holmes CFB (1995). Tissue

      distribution and clearance of tritium-labeled dihydromicrocystin-LR

      epimers administered to Atlantic salmon via intraperitoneal injection.

      Toxicon 33:125-131

                         ****** PHYSIOLOGY ******

Bonilla I, Bolanos L, Mateo P (1995). Interaction of boron and calcium in the

      cyanobacteria Anabaena and Synechococcus. Physiol Plant 94:31-36

Evans DJ, Evans DG, Lampert HC, Nakano H (1995). Identification of four new

      prokaryotic bacterioferritins, from Helicobacter pylori, Anabaena

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                     ****** MEMBRANES & LIPIDS ******

Avelange-Macherel MH, Macherel D, Wada H, Murata N (1995). Site-directed

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                      ****** STRESS RESPONSES ******

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                     ****** NITROGEN METABOLISM ******

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               ****** NITROGENASE and DIFFERENTIATION ******

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                      ****** CARBON METABOLISM ******

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               ****** PHOTOSYNTHESIS and PHOTOSYSTEMS ******

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              ****** PHYCOBILISOMES and OTHER PIGMENTS ******

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            ****** ELECTRON TRANSPORT and BIOENERGETICS ******

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Brown II (1994). Hypothesis - Is Ca2+ the third coupling ion? Biochemistry-

      Engl Tr 59:1321-1323

Steinemann D, Engelbrecht S, Lill H (1995). Reassembly of Synechocystis sp

      PCC 6803 F-1-ATPase from its over-expressed subunits. FEBS Lett 362:171-



Churin YN, Shalak IN, Borner T, Shestakov SV (1995). Physical and genetic map

      of the chromosome of the unicellular cyanobacterium Synechocystis sp

      strain PCC 6803. J Bacteriol 177:3337-3343

Barten R, Lill H (1995). DNA-uptake in the naturally competent cyanobacterium,

      Synechocystis sp PCC 6803. FEMS Microbiol Lett 129:83-88

Moser D, Zarka D, Hedman C, Kallas T (1995). Plasmid and chromosomal DNA

      recovery by electroextraction of cyanobacteria. FEMS Microbiol Lett


Zaug AJ, Davilaaponte JA, Cech TR (1994). Catalysis of RNA cleavage by a

      ribozyme derived from the group I intron of Anabaena pre-tRNALeu.

      Biochemistry 33:14935-14947

Kim ST, Sancar A (1995). Photorepair of nonadjacent pyrimidine dimers by DNA

      photolyase. Photochem Photobiol 61:171-174

Nagaraja R, Haselkorn R (1994). Protein HU from the cyanobacterium Anabaena.

      Biochimie 76:1082-1089

Robinson NJ, Robinson PJ, Gupta A, Bleasby AJ, Whitton BA, Morby AP (1995).

      Singular over-representation of an octameric palindrome, HIP1, in DNA

      from many cyanobacteria. Nucl Acids Res 23:729-735

Kawaguchi R, Nagaoka T, Burgess JG, Takeyama H, Matsunaga T (1994). Sequence

      of a 2.6-kb cryptic plasmid from a marine cyanobacterium Synechococcus

      sp. Plasmid 32:245-253

Durner J, Boger P (1995). Ubiquitin in the prokaryote Anabaena variabilis. J

      Biol Chem 270:3720-3725

Mann NH (1994). Protein phosphorylation in cyanobacteria. Microbiol UK


Nakai M, Goto A, Nohara T, Sugita D, Endo T (1994). Identification of the SecA

      protein homolog in pea chloroplasts and its possible involvement in

      thylakoidal protein transport. J Biol Chem 269:31338-31341

Packer JCL, Andre D, Howe CJ (1995). Cloning and sequence analysis of a signal

      peptidase I from the thermophilic cyanobacterium Phormidium laminosum.

      Plant Mol Biol 27:199-204

Sugita M, Sugita C, Sugiura M (1995). Structure and expression of the gene

      encoding ribosomal protein S1 from the cyanobacterium Synechococcus sp

      strain PCC 6301: Striking sequence similarity to the chloroplast

      ribosomal protein CS1. Mol Gen Genet 246:142-147

Sarma TA, Singh R (1995). Characterization of ts-mutants of cyanophage N-1.

      By their inactivation by physical and chemical agents. Acta Virol 39:65-


                  ****** APPLIED CYANOBACTERIOLOGY ******

Duan Xue-Y, Shi Ding-J, Wu Xiao-Q, Wu Yu-H, Qiu Ze-S (1994). The effects of

      immobilization on the activity of glutamine synthetase and the

      expression of the glnA gene in Anabaena sp. strain 2B. Chinese J Bot


Miura Y (1995). Hydrogen production by biophotolysis based on microalgal

      photosynthesis. Process Biochem 30:1-7

Murphy RC, Stevens SE (1995). Development of a cyanobacterial biolarvicide.

      Mem Inst Oswaldo Cruz 90:109-113

Orduz S, Restrepo W, Patino MM, Rojas W (1995). Transfer of toxin genes to

      alternate bacterial hosts for mosquito control. Mem Inst Oswaldo Cruz


Shi D, Wu X, Hao Y, Qiu Z (1994). Effects of immobilization on ammonia

      secretion and the activity of glutamine synthetase in Nostoc

      flagelliforme. Bot Res 7:331-334 [Chinese; Engl Summary]

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      cryIVB expression in the cyanobacterium Synechococcus PCC 7942. Mol Gen

      Genet 246:301-308

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      nitrogen fixing cyanobacteria in rice fields of Bangladesh. Phykos


Painter TJ (1995). Biofertilizers: Exceptional calcium binding affinity of a

      sheath proteoglycan from the blue-green soil alga Nostoc calcicola.

      Carbohyd Polym 26:231-233

Doumenge F, Durand-Chastel H, Toulemont A (eds) (1993) Spirulina: Algae of

      Life. Musee Oceanographique, Monaco

Kapoor R, Mehta U (1992). Iron bioavailability from Spirulina platensis, whole

      egg and whole wheat. Indian J Exp Biol 30:904-907

Kapoor R, Mehta U (1993). Iron status and growth of rats fed different dietary

      iron sources. Plant Foods Hum Nutr 44:29-34

Marquez FJ, Sasaki K, Kakizono T, Nishio N, Nagai S (1993). Growth

      characteristics of Spirulina platenis in mixotrophic and heterotrophic

      conditions. J Ferment Bioeng 76:408-410 

Ogbonna JC, Yada H, Tanaka H (1995). Effect of cell movement by random mixing

      between the surface and bottom of photobioreactors on algal

      productivity. J Ferment Bioeng 79:152-157

Olguin EJ, Hernandez B, Araus A, Camacho R, Gonzalez R, Ramirez ME, Galicia

      S, Mercado G (1994). Simultaneous high-biomass protein production and

      nutrient removal using Spirulina maxima in sea water supplemented with

      anaerobic effluents. world j microbiol biotechnol 10:576-578

Singh G, Kothari RM, Sharma RK, Ramamurthy V (1995). Enhancement of Spirulina

      biomass productivity by a protein hydrolysate. Appl Biochem Biotechnol


Tanticharoen M, Reungjitchachawali M, Boonag B, Vonktaveesuk P, Vonshak A,

      Cohen Z (1994). Optimization of gamma -linolenic acid (GLA) production

      in Spirulina platensis. J Appl Phycol 6:295-300

Vonshak A, Torzillo G, Tomaseli L (1994). Use of chlorophyll fluorescence to

      estimate the effect of photoinhibition in outdoor cultures of Spirulina

      platensis. J Appl Phycol 6:31-34

Canizares RO, Dominguez AR, Rivas L, Montes MC, Traveiso L, Benitez F (1993).

      Free and immobilized cultures of Spirulina maxima for swine waste

      treatment. Biotechnol Lett 15:321-326

Canizares RO, Rivas L, Montes C, Traveiso L, Benitez F (1994). Aerated swine-

      wastewater treatment with K-carrageenan-immobilized Spirulina maxima.

      Bioresourc Technol Biomass 47:89-91

Canizares-Villanueva RO, Ramos A, Lemus R, Gomez-Lojero C, Travieso L (1994).

      Growth of Phormidium sp in aerobic secondary piggery waste-water. Appl

      Microbiol Biotechnol 42:487-491

Kuritz T, Wolk CP (1995). Use of filamentous cyanobacteria for biodegradation

      of organic pollutants. Appl Environ Microbiol 61:234-238 (Correction:

      vol 61, pg 234, 1995)

Sorkhoh NA, Alhasan RH, Khanafer M, Radwan SS (1995). Establishment of oil-

      degrading bacteria associated with cyanobacteria in oil-polluted soil.

      J Appl Bacteriol 78:194-199




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AUSTRALIA     Steve Delaney            Department of Biotechnology,

 /NEW ZEALAND                          University of New South Wales, P.O.

                                       Box 1, Kensington, New South Wales

                                       AUSTRALIA 2033 (Tel) 02-697-2056

AUSTRIA       Georg Schmetterer        Institut fur Physikalische Chemie,

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CANADA        Neil Strauss             Dept. of Botany, University of

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                                       (Fax) 416-978-5878

                                       (E-mail) Straus@Botany.UToronto.Ca

P.R.CHINA     Chao-Tsi Tseng           Centre of Marine Sciences, Dept. 

                                       of Biology, Nanjing University,

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                                       (Fax) 086025-302728

FRANCE        Nicole Tandeau de Marsac Physiologie Microbienne, Institut

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INDIA         Joe Thomas               Biotechnology Division, SPIC Science

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ISRAEL        Elisha Tel-Or            Dept. of Agricultural Botany, The

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ITALY         Mario Tredici            Departimento di Scienze e Tecnologie

                                       Alimentari e Microbiologiche.

                                       Universita degli Studi di Firenze,

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                                       (Fax) 31-20-525-5802

                                       (E-mail) A417LMur@Horus.Sara.NL

SCANDANAVIA   Olav Skulberg            Norwegian Institute for Water

                                       Research, P.O.box 69 Korsvall, N-0808

                                       Oslo 8 NORWAY. (Tel) 47 22 185266

                                       (Fax) 47 22 185200

U.K.          Tony Walsby              Dept. of Botany, University of

                                       Bristol, Bristol BS8 1UG.

                                       (Tel) 0272-303030

ANYWHERE ELSE Jeff Elhai               Dept. of Biological Sciences, Florida

                                       International University, University

                                       Park Campus, Miami FL 33199 USA. 

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                                       (E-mail) Cyano@Servax.Fiu.Edu