CYANONEWS 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. HOW TO FIND OUT MORE ABOUT SOMETHING YOU READ HERE - Each news item contains, prominently displayed, the name of a contact person. A Directory of Cyanobacteriologists is distributed every two years or on request. INSTRUCTIONS TO AUTHORS - Send news. 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. ============================================================================== CONTENTS*CONTENTS*CONTENTS*CONTENTS*CONTENTS*CONTENTS*CONTENTS*CONTENTS*CONTEN ============================================================================== BULLETIN BOARD * 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 TRANSITIONS * Comings and goings of ourselves * David Laudenbach NEWS * Allen's teaching toasted * Foreign gene expression tamed * Immobilized cells' boosted NH3 output tied to glutamine synthetase expression * Meeting Report: Congress on N2 Fixation * Meeting report: Euro Workshop on Mol Bio REFERENCES ADDRESSES ============================================================================== BULLETIN BOARD*BULLETIN BOARD*BULLETIN BOARD*BULLETIN BOARD*BULLETIN BOARD*BUL ============================================================================== ****** 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 CHANGES IN PHOTOSYSTEM SEGREGATION AND STACKING. He wants to use thylakoid 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 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 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 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 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.) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 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 ****** The 15TH NORTH AMERICAN SYMBIOTIC NITROGEN FIXATION CONFERENCE will be held 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 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 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 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - The FIRST INTERNATIONAL CONGRESS ON TOXIC CYANOBACTERIA is the new descendent 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 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - The INTERNATIONAL ASSOCIATION OF APPLIED ALGOLOGY will hold its Congress in 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 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - The 13TH INTERNATIONAL SYMPOSIUM ON CYANOPHYTE RESEARCH will take place in 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 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 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 photosynthesis" 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 ****** POSITION OFFERED: Post-Doc 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 AVAILABLE: Oct 1995 SEND: CV and three letters of recommendation - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - POSITION OFFERED: Post-Doc 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 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - POSITION OFFERED: Post-Doc 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 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - POSITION OFFERED: Post-Doc 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 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - POSITION OFFERED: Post-Doc 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 efficiency. 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 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 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 7:623] 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. ============================================================================== TRANSITIONS*TRANSITIONS*TRANSITIONS*TRANSITIONS*TRANSITIONS*TRANSITIONS*TRANSI ============================================================================== 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 ============================================================================== NEWS*NEWS*NEWS*NEWS*NEWS*NEWS*NEWS*NEWS*NEWS*NEWS*NEWS*NEWS*NEWS*NEWS*NEWS*NEW ============================================================================== ALLEN ACCLAIMED BY NATIONAL SOCIETY 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 cyanobacteria. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - CONTROLLED EXPRESSION OF FOREIGN GENES IN CHROMOSOMES OF SYNECHOCOCCUS 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) tested. The work has recently been fully described [Geerts et al (1995) Microbiol-UK 141:831-841]. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - EXCRETION OF AMMONIA FROM IMMOBILIZED ANABAENA EXPLAINED 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 earlier. 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)]. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - X INTERNATIONAL CONGRESS ON NITROGEN FIXATION - MEETING REPORT 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 donor(s). 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 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - EUROPEAN WORKSHOP ON THE MOLECULAR BIOLOGY OF CYANOBACTERIA - MEETING REPORT ****** 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 heterocysts. 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 ****** NITROGEN REGULATION/METABOLISM AND N2 FIXATION ****** 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 formation. 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 CAPABILITY OF NONHETEROCYSTOUS CYANOBACTERIA TO FIX NITROGEN predominantly in 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 ============================================================================== REFERENCES*REFERENCES*REFERENCES*REFERENCES*REFERENCES*REFERENCES*REFERENCES*R ============================================================================== ****** 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. 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Turbulence and planktonic nitrogen fixation: A mesocosm experiment. Limnol Oceanogr 38:1696-1711 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 15:321-336 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. 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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 268:1480-1482 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) 56:1123-1129 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 36:1189-1192 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 117:5612-5613 ****** 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 39:301-303 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 306:657-665 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 variabilis, Bacillus subtilis and Treponema pallidum, by analysis of gene sequences. Gene 153:123-127 Falkner G, Wagner F (1994). The blue-green alga Anacystis nidulans can store information about previous phosphate fluctuations in the kinetic and energetic properties of the high affinity phosphate uptake system. In: Gnaiger E, Gellerich FN, Wyss M (eds) What Is Controlling Life? Publisher: Innsbruck Univ Press, Publikationsstelle Univ, Innsbruck, Austria Kashiwagi S, Irie J, Kanamaru K, Mizuno T (1994). Cloning and sequencing of a Synechococcus gene encoding a protein very similar to mammalian aldehyde dehydrogenases. Biosci Biotechnol Biochem 58:2299-2300 Muniz WH, Stevens SE (1994). Development of motility in cultures of the cyanobacterium Mastigocladus laminosus. FEMS Microbiol Ecol 15:259-264 Pena MMO, Burkhart W, Bullerjahn GS (1995). 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J Appl Bacteriol 78:194-199 ============================================================================== ADDRESSES*ADDRESSES*ADDRESSES*ADDRESSES*ADDRESSES*ADDRESSES*ADDRESSES*ADDRESSE ============================================================================== Send CONTRIBUTIONS to one of the addresses listed below. There is no charge to receive the newsletter electronically, and you may receive the electronic version even weeks earlier than others would receive the printed version. To get on the ELECTRONIC MAILING LIST, send your name, telephone, fax, and E-mail numbers (if any), and a brief description of your research interests for inclusion in the next Directory of Cyanobacteriologists and the name and model number of printer(s) available to you. To obtain a PRINTED VERSION OF THE NEWSLETTER BY MAIL, send $10 U.S. (please, no checks except in U.S. currency) per year to Jeff Elhai, along with the same information mentioned above (except printer name). If it is difficult for you to send hard currency, send a note indicating your interest. 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, Wahringerstrasse 42, A-1090 Wien (Tel) 43-1-31367-2555 (EMail) A8422dad@Awiuni11 CANADA Neil Strauss Dept. of Botany, University of Toronto, Toronto, Ontario M5S 1A1. (Tel) 416-978-3532/5563 (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, Nanjing. (Tel) 637551-2551 (Fax) 086025-302728 FRANCE Nicole Tandeau de Marsac Physiologie Microbienne, Institut Pasteur, 29 rue du Dr. Roux, 75724 Paris Cedex 15. (Tel) 567-46-98 (Fax) 40.56.01.25 (EMail) NTMarsac@Pasteur.Fr GERMANY Wolfgang Lockau Biochemie der Pflanzen, Fachbereich Biologie, Humboldt-Universit„t, Invalidenstr. 42, 10 115 Berlin (Tel) 30-2897-2686 (Fax) 30-2897-2641 INDIA Joe Thomas Biotechnology Division, SPIC Science Foundation, 110 Mount Road, Madras 600 032. (Tel) 432342 (Fax) 432163 ISRAEL Elisha Tel-Or Dept. of Agricultural Botany, The Hebrew University, Rehovot 76100 (Tel) 08-481262 ITALY Mario Tredici Departimento di Scienze e Tecnologie Alimentari e Microbiologiche. Universita degli Studi di Firenze, P.le.delle Cascine 27 51044 Firenze. (Tel) 055-352051 (Fax) 055-330431 (E-mail) Tredici@Csma.Fi.Cnr.It NETHERLANDS Luuc Mur Laboratorium voor Microbiologie, Universiteit voor Amsterdam, Nieuwe Achtergracht 127, 1018 WS Amsterdam (Tel) 31-20-525-7056 (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. (Tel) 305-348-3584, (Fax)305-348-1986 (E-mail) Cyano@Servax.Fiu.Edu