DOCSLIB.ORG

Growth of the Cyanobacterium Anabaena on Molecular Nitrogen: Nifj Is Required When Iron Is Limited CHRISTOPHER C

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Growth of the Cyanobacterium Anabaena on Molecular Nitrogen: Nifj Is Required When Iron Is Limited CHRISTOPHER C Proc. Natl. Acad. Sci. USA Vol. 90, pp. 8812-8816, October 1993 Plant Biology Growth of the cyanobacterium Anabaena on molecular nitrogen: NifJ is required when iron is limited CHRISTOPHER C. BAUER, LoRi SCAPPINO, AND ROBERT HASELKORN Department of Molecular Genetics and Ceil Biology, University of Chicago, 920 East 58th Street, Chicago, IL 60637 Contributed by Robert Haselkorn, June 21, 1993 ABSTRACT The nifJ gene of KkebsieUa pneumoniae en- lents of nifJ or niJF in photosynthetic prokaryotes, with two codes an oxidoreductase required for the transfer of electrons exceptions. A homologue of nifJ was detected in Rhodospi- from pyruvate to flavodoxin, which reduces nitrogenase. The rillum rubrum; the protein has been purified, and the gene has nifJ gene ofAnabaena 7120, isolated from a cosmid bank, was been sequenced, but its requirement for nitrogen fixation has found to contain an open reading frame encoding a 1197-aa not been established (8). The second exception is described protein. The deduced amino acid sequence shows 50% identity in this report. Anabaena 7120 contains a nifJ gene that is to the KkebsieUa homolog. The nifJ gene in Anabaena 7120 was dispensable for growth on normal cyanobacterial medium but inactivated by chromosomal interruption. The resulting mu- is essential for growth on medium depleted of iron and tant was unable to grow on medium depleted of both iron and combined nitrogen. Growth of cyanobacteria on iron- combined nitrogen but grew normally, fixng nitrgen, when depleted medium generally results in replacement of ferre- Iron was present. NiU transcripts of2.7 and 4.3 kb are induced doxin with flavodoxin (9, 10). Thus, the electron transfer path by iron depletion irrespective ofnitrogen status. One particular from pyruvate to flavodoxin to nitrogenase may operate in stretch of the Anabaena 7120 nifJ gene encodes 12 aa with no Anabaena as an alternative to a path through ferredoxin complementary matches in the Kkebsiela protein. This insert when iron is limiting. Additionally, the Anabaena nifJ gene contains five tandem repeats of the heptamer CCCCAGT. contains short tandemly repeated sequences within the open These heptamers, as well as heptamers and octamers of other reading frame (ORF), resulting in the apparent insertion ofan related sequences, have been located in a number of cyano- exceptional peptide in the interior of the protein. Other bacterial genomes but are usually not found within the coding strains of cyanobacteria with nifJ genes also have inserted region of a gene. The site of the Anabaena 7120 heptamers in peptides in this same site but the inserted peptides vary in the nifJ genes of other filamentous cyanobacteria contains a their sizes and sequences. surprising diversity of repeated sequences, both octamers and heptamers. The corresponding protein inserts range in length from 1 to 21 aa, relative to KkebsieUa NiO. MATERIALS AND METHODS Culture Conditions. Anabaena 7120 was grown in modified Biological nitrogen fixation is catalyzed by the nitrogenase Kratz and Myers medium C (termed KM) or in medium enzyme complex. Dinitrogen is bound to the molybdenum- BG-11 (11, 12). Half of the Na2HPO4, 1.125 mM, was iron cofactor of nitrogenase, where it is reduced by three replaced with K2HPO4 in the KM medium. Nitrogen sources successive two-electron two-proton transfers. The electrons were either 2.5 mM (NH4)2SO4 or 17.6 mM NaNO3. Plates are donated by an iron-sulfur center in nitrogenase reduc- contained KM or BG-11 with 17.6 mM NaNO3 (if a nitrogen tase. That center can be reduced, in turn, by a variety of source was included) and 1.3% BBL purified agar. Iron- redox proteins, such as flavodoxins or ferredoxins, that link limited plates contained BG-11 without the ferric ammonium nitrogen fixation to sources of reductant from glycolysis or citrate component. Flame atomic absorption spectrophoto- photosynthesis (1). metric analysis of this medium found no detectable iron. The earliest complete picture of the genes required for Aqueous extracts of the agar also yielded no detectable iron nitrogen fixation was obtained for Klebsiellapneumoniae (2). by atomic absorption spectrophotometry. Small cultures Two of these genes, nifJ and nip;, encode proteins involved were grown under cool white fluorescent light at 30-40 ,uE in electron transfer to nitrogenase. NifF is a flavodoxin and per m2 per sec (where E is einstein; 1E = 1 mol of photons) Niff is a pyruvate:flavodoxin oxidoreductase. Mutations in at 25-30°C in an incubator gassed with 2% C02/98% air. either of these genes reduce nitrogenase activity =20-fold, Large-scale cultures were bubbled with 2% C02/98% air. For suffi'cient to prevent growth on N2 as the nitrogen source (3). Anabaena strains containing recombinant plasmids, selec- The residual activity of nitrogenase in these mutants is tion was made with neomycin at 30 ,g/ml. After chromo- probably due to a low constitutive level of ferredoxin. somal insertion ofthe plasmid, selection was maintained with In photosynthetic bacteria and cyanobacteria, the nif and neomycin at 100 ,g/ml. For selective growth of Escherichia nifJ genes are dispensable because photosynthesis produces coli DH5a carrying plasmids, ampicillin at 100 iLg/ml and enough reduced ferredoxin to support nitrogen fixation. kanamycin sulfate at 50 ug/ml were used. Heterocysts ofthe cyanobacterium Anabaena 7120 contain a Molecular Biology Techniques. All cloning, DNA manipu- unique ferredoxin, the fdxH gene product, that is the prin- lations, and gel electrophoresis were as described (13). cipal electron donor to nitrogenase in that organism (4). Southern and Northern blot hybridizations, the preparation Anabaena strains contain a flavodoxin whose abundance can of nested deletions, and DNA sequencing were as described be increased by iron starvation (5), but an early report that (14). this flavodoxin can donate electrons to Anabaena nitroge- RNA Isolation. Large-scale cultures of Anabaena 7120 nase (6) has not been confirmed (7). To date, both biochem- were induced to differentiate by transferring cells from KM ical and genetic approaches have failed to identify equiva- with NH4 to KM without combined nitrogen. For iron limitation, cells were grown to midlogarithmic phase (chlo- at 2-6 0.7-2 x 107 cells per ml) in BG-11 The publication costs of this article were defrayed in part by page charge rophyll ug/ml; payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact. Abbreviation: ORF, open reading frame. 8812 Downloaded by guest on September 26, 2021 Plant Biology: Bauer et aL Proc. Natl. Acad. Sci. USA 90 (1993) 8813 with NH4 and then transferred to BG-11 without combined Table 1. Growth of wild-type and nifJ mutants of nitrogen or ferric ammonium citrate. One-liter cultures har- Anabaena 7120 vested at 6-hr intervals and purified heterocysts from S liters Growth condition Wild type nifJ mutants of 24-hr-induced cultures were used to prepare total RNA as + + + described by Golden et aL (15). For the Northern blot in Fig. BG-11 N03 Fe + BG-llo + Fe + + 2, the RNA preparation was changed as follows: aurin BG-11 + N03 - Fe + + tricarboxylic acid was substituted for vanadyl ribonucleoside BG-lo- Fe + as the nuclease inhibitor and a 4 M LiCl precipitation was added to separate RNA from DNA and polysaccharides. An Cultures were incubated on agar plates for 2 weeks in an incubator Anabaena flavodoxin gene probe was generously provided under fluorescent lighting in 2%6 C02/98% air. BG-11o has no added NO3 or NHZ. Medium with Fe contained 32 pM ferric ammonium by N. Straus (University of Toronto) (16). citrate. Three independent isolates of nifJ insertional mutants were Heterocyst-Specific Subtracted cDNA Library. The details used. ofconstruction ofdevelopmental stage-specific cDNA librar- ies are described elsewhere (17). The heterocyst-specific RESULTS library from which a fragment of the nifJ gene was isolated Identification of a nifJ-Like Gene. Anabaena 7120 contains was prepared as follows. Total heterocyst RNA was prepared a gene related to K. pneumoniae nifJ. This gene was discov- as described (15) and then used as a template for first-strand ered first as a fragment in a cDNA library corresponding to cDNA synthesis with reverse transcriptase, priming with a the RNAs present uniquely in heterocysts, the cells special- complete set of random hexamers (Pharmacia). RNA was ized for nitrogen fixation in filaments ofAnabaena. Ofthe 50 removed by treatment with RNase H and RNase A and then fragments from that library that were sequenced, 1 fragment the nucleases were removed by phenol extraction. Next, a contained a stretch of 261 nt that, when translated, is highly 10-fold excess of vegetative-cell RNA was annealed to the similar to a portion of the Klebsiella nifJ gene product. DNA, to prevent those cDNAs corresponding to vegetative- The putative nifJ cDNA was used to screen a cosmid cell RNA from serving as template for second-strand cDNA library ofAnabaena 7120 chromosomal DNA fragments. One synthesis. The second-strand DNA synthesis was carried out cosmid identified by the probe was reduced by deletion and with the Klenow fiagment of DNA polymerase I, using the then Ssp I fiagments spanning the entire ORF were sub- same collection of random hexamers to prime. The resulting cloned and sequenced (Fig. 1). The ORF contains 1197 aa, double-stranded DNA fragments were filed-in with T4 DNA with a predicted molecular weight of 132,166. With the polymerase, ligated into appropriately cut pUC19, and used exception ofa 12-aa insertion in the Anabaena sequence, the to transform E. coli DHSa. Anabaena and Klebsiella Nifi sequences are very similar: Cloning and Sequence Determination of the nifJ Gene. Fifty 50%6 of the residues are identical and an additional 19%o are clones from the heterocyst-specific library were sequenced similar.
Load more

Recommended publications
  • Azolla-Anabaena Symbiosis-From Traditional Agriculture to Biotechnology
    Indian Journal of Biotechnology Vol 2, January 2003, pp 26-37 Azolla-Anabaena Symbiosis-From Traditional Agriculture to Biotechnology Anjuli Pabby, Radha Prasanna and P K Singh* National Centre for Conservation and Utilization of Blue-Green Algae, Indian Agricultural Research Institute, New Delhi 110 012, India The Azolla - Anabaena symbiosis has attracted attention as a biofertilizer worldwide, especially in South East Asia. But its utilization and genetic improvement has been limited mainly due to problems associated with the isolation and characterization of cyanobionts and the relative sensitivity of the fern to extremes of temperature and light intensity. This paper reviews the historical background of Azolla, its metabolic capabilities and present day utilization in agriculture. An outline of biotechnological interventions, carried out in India and abroad, is also discussed for a better understanding of the symbiotic interactions, which can go a long way in further exploitation of this association in agriculture and environmental management. Keywords: Azolla, Anabaena, biofertilizer, fingerprinting, symbiont Introduction food and medicine, besides its role in environmental Azolla is a small aquatic fern of demonstrated management and as controlling agent for weeds and agronomic significance in both developed and mosquitoes. It also improves water quality by removal developing countries (Singh, 1979a; Lumpkin & of excess quantities of nitrate and phosphorus and is Plucknett, 1980; Watanabe, 1982; Giller, 2002). The also used as fodder, feed for fish, ducks and rabbits association between Azolla and Anabaena azollae is a (Wagner, 1997). Besides its extensive use as a N- symbiotic one, wherein the eukaryotic partner Azolla supplement in rice-based ecosystems, it has also been houses the prokaryotic endosymbiont in its leaf used in other crops such as taro, wheat, tomato and cavities and provides carbon sources and in turn banana (Van Hove, 1989; Marwaha et al.
    [Show full text]
  • Understanding the Interaction Between Anabaena Sp. and a Heterocyst-Specific Epibiont
    Understanding the interaction between Anabaena sp. and a heterocyst-specific epibiont Iglika V. Pavlova MBL Microbial Diversity course 2005 Abstract Anabaena sp. and an associated heterocyst-specific epibiontic bacterium were isolated from School Street Marsh in Woods Hole, MA in 1997 during the Microbial Diversity course. A two-member culture of the cyanobacterium and the epibiont have been maintained at WHOI by John Waterbury. Anabaena species with similar heterocyst-specific epibionts have also been isolated from other locations (7, 8, 9). Successful culture of the epibiont separately from the School Street Marsh cyanobacterium was achieved on two occasions (1, 10), but the isolates were not preserved. The epibiont was identified to be an α-proteobacterium within the Rhizobiaceae group (10). The close and specific association between the cyanobacterium and the epibiont strongly suggests there might be a physiological benefit or benefits to the cyanobacterium, the epibiont, or to both partners. This study was designed to understand the potential benefits of the interaction for the epibiontic bacterium. Several approaches were used to isolate the epibiont in pure culture, unsuccessfully. This report describes the rationale for undertaking the project and the approaches used to isolate the epibiont, in the hopes that this will be useful information for the future isolation of an axenic epibiont culture. Rationale Cyanobacterial associations with heterotrophic bacteria from environmental isolates have been described before and have been implicated in increasing the growth of the cyanobacterium (5, 6, 7). Benefit to the cyanobacterium may be derived from a range of associations, including the presence of heterotrophic bacteria in the culture medium, attraction of such bacteria to cyanobacterial secretions (either along the whole filament, or secretions stemming from the heterocyst in filamentous bacteria), or the attachment of the bacterium to the cyanobacterium outer surface (5, 6, 7, 9).
    [Show full text]
  • Natural Product Gene Clusters in the Filamentous Nostocales Cyanobacterium HT-58-2
    life Article Natural Product Gene Clusters in the Filamentous Nostocales Cyanobacterium HT-58-2 Xiaohe Jin 1,*, Eric S. Miller 2 and Jonathan S. Lindsey 1 1 Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, USA; [email protected] 2 Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695-7615, USA; [email protected] * Correspondence: [email protected] Abstract: Cyanobacteria are known as rich repositories of natural products. One cyanobacterial- microbial consortium (isolate HT-58-2) is known to produce two fundamentally new classes of natural products: the tetrapyrrole pigments tolyporphins A–R, and the diterpenoid compounds tolypodiol, 6-deoxytolypodiol, and 11-hydroxytolypodiol. The genome (7.85 Mbp) of the Nostocales cyanobacterium HT-58-2 was annotated previously for tetrapyrrole biosynthesis genes, which led to the identification of a putative biosynthetic gene cluster (BGC) for tolyporphins. Here, bioinformatics tools have been employed to annotate the genome more broadly in an effort to identify pathways for the biosynthesis of tolypodiols as well as other natural products. A putative BGC (15 genes) for tolypodiols has been identified. Four BGCs have been identified for the biosynthesis of other natural products. Two BGCs related to nitrogen fixation may be relevant, given the association of nitrogen stress with production of tolyporphins. The results point to the rich biosynthetic capacity of the HT-58-2 cyanobacterium beyond the production of tolyporphins and tolypodiols. Citation: Jin, X.; Miller, E.S.; Lindsey, J.S. Natural Product Gene Clusters in Keywords: anatoxin-a/homoanatoxin-a; hapalosin; heterocyst glycolipids; natural products; sec- the Filamentous Nostocales ondary metabolites; shinorine; tolypodiols; tolyporphins Cyanobacterium HT-58-2.
    [Show full text]
  • Planktothrix Agardhii É a Mais Comum
    Accessing Planktothrix species diversity and associated toxins using quantitative real-time PCR in natural waters Catarina Isabel Prata Pereira Leitão Churro Doutoramento em Biologia Departamento Biologia 2015 Orientador Vitor Manuel de Oliveira e Vasconcelos, Professor Catedrático Faculdade de Ciências iv FCUP Accessing Planktothrix species diversity and associated toxins using quantitative real-time PCR in natural waters The research presented in this thesis was supported by the Portuguese Foundation for Science and Technology (FCT, I.P.) national funds through the project PPCDT/AMB/67075/2006 and through the individual Ph.D. research grant SFRH/BD65706/2009 to Catarina Churro co-funded by the European Social Fund (Fundo Social Europeu, FSE), through Programa Operacional Potencial Humano – Quadro de Referência Estratégico Nacional (POPH – QREN) and Foundation for Science and Technology (FCT). The research was performed in the host institutions: National Institute of Health Dr. Ricardo Jorge (INSA, I.P.), Lisboa; Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), Porto and Centre for Microbial Resources (CREM - FCT/UNL), Caparica that provided the laboratories, materials, regents, equipment’s and logistics to perform the experiments. v FCUP Accessing Planktothrix species diversity and associated toxins using quantitative real-time PCR in natural waters vi FCUP Accessing Planktothrix species diversity and associated toxins using quantitative real-time PCR in natural waters ACKNOWLEDGMENTS I would like to express my gratitude to my supervisor Professor Vitor Vasconcelos for accepting to embark in this research and supervising this project and without whom this work would not be possible. I am also greatly thankful to my co-supervisor Elisabete Valério for the encouragement in pursuing a graduate program and for accompanying me all the way through it.
    [Show full text]
  • Anabaena Variabilis ATCC 29413
    Standards in Genomic Sciences (2014) 9:562-573 DOI:10.4056/sig s.3899418 Complete genome sequence of Anabaena variabilis ATCC 29413 Teresa Thiel1*, Brenda S. Pratte1 and Jinshun Zhong1, Lynne Goodwin 5, Alex Copeland2,4, Susan Lucas 3, Cliff Han 5, Sam Pitluck2,4, Miriam L. Land 6, Nikos C Kyrpides 2,4, Tanja Woyke 2,4 1Department of Biology, University of Missouri-St. Louis, St. Louis, MO 2DOE Joint Genome Institute, Walnut Creek, CA 3Lawrence Livermore National Laboratory, Livermore, CA 4Lawrence Berkeley National Laboratory, Berkeley, CA 5Los Alamos National Laboratory, Los Alamos, NM 6Oak Ridge National Laboratory, Oak Ridge, TN *Correspondence: Teresa Thiel ([email protected]) Anabaena variabilis ATCC 29413 is a filamentous, heterocyst-forming cyanobacterium that has served as a model organism, with an extensive literature extending over 40 years. The strain has three distinct nitrogenases that function under different environmental conditions and is capable of photoautotrophic growth in the light and true heterotrophic growth in the dark using fructose as both carbon and energy source. While this strain was first isolated in 1964 in Mississippi and named Ana- baena flos-aquae MSU A-37, it clusters phylogenetically with cyanobacteria of the genus Nostoc . The strain is a moderate thermophile, growing well at approximately 40° C. Here we provide some additional characteristics of the strain, and an analysis of the complete genome sequence. Introduction Classification and features Anabaena variabilis ATCC 29413 (=IUCC 1444 = The general characteristics of A. variabilis are PCC 7937) is a semi-thermophilic, filamentous, summarized in Table 1 and its phylogeny is shown heterocyst-forming cyanobacterium.
    [Show full text]
  • Umezakia Natans M.Watan. Does Not Belong to Stigonemataceae but To
    Fottea 11(1): 163–169, 2011 163 Umezakia natans M.WATAN . does not belong to Stigonemataceae but to Nostocaceae Yuko NIIYAMA 1, Akihiro TUJI 1 & Shigeo TSUJIMURA 2 1Department of Botany, National Museum of Nature and Science, 4–1–1 Amakubo, Tsukuba, Ibaraki 305–0005, Japan; e–mail: [email protected] 2Lake Biwa Environmental Research Institute, 5–34 Yanagasaki, Otsu, Shiga 520–0022, Japan Abstract: Umezakia natans M.WA T A N . was described by Dr. M. Watanabe in 1987 as a new species in the family of Stigonemataceae, following the rules of the Botanical Code. According to the original description, this planktonic filamentous species grows well in a growth media with pH being 7 to 9, and with a smaller proportion of sea water. Both heterocytes and akinetes were observed, as well as true branches developing perpendicular to the original trichomes in cultures older than one month. Watanabe concluded that Umezakia was a monotypic and only planktonic genus belonging to the family of Stigonemataceae. Unfortunately, the type culture has been lost. In 2008, we successfully isolated a new strain of Umezakia natans from a sample collected from Lake Suga. This lake is situated very close to the type locality, Lake Mikata in Fukui Prefecture, Japan. We examined the morphology of this U. natans strain, and conducted a DNA analysis using 16S rDNA regions. Morphological characters of the newly isolated strain were in a good agreement with the original description of U. natans. Furthermore, results of the DNA analysis showed that U. natans appeared in a cluster containing Aphanizomenon ovalisporum and Anabaena bergii.
    [Show full text]
  • Protein Phosphorylation and a Novel Phosphatase in the Cyanobacterium Anabaena
    Cyanobacteria 1 Running head: CYANOBACTERIA Protein Phosphorylation and a Novel Phosphatase in the Cyanobacterium Anabaena Robert Mullis A Senior Thesis submitted in partial fulfillment of the requirements for graduation in the Honors Program Liberty University Spring 2008 Cyanobacteria 2 Acceptance of Senior Honors Thesis This Senior Honors Thesis is accepted in partial fulfillment of the requirements for graduation from the Honors Program of Liberty University. _______________________________ L. Daniel Howell, Ph.D. Chairman of Thesis _______________________________ Mark Hemric, Ph.D. Committee Member _______________________________ Emily Heady, Ph.D. Committee Member _______________________________ Brenda Ayres, Ph.D. Honors Assistant Director _______________________________ Date Cyanobacteria 3 Abstract The focus of this paper is a dual-specific protein phosphatase (DSP) previously found in the periplasm of the cyanobacterium Anabaena PCC 7120 that may regulate circadian rhythms in that organism. To fully understand the topic, summaries of enzyme action, cyanobacteria, circadian rhythms, and phosphorylation cycles are required and therefore discussed in this report before the presentation of previous and current laboratory research centered on the phosphatase. A continuous cyanobacterial culture was maintained while cells were collected for harvesting periplasm. Tests to determine size, enzyme activity, and protein content were performed on the periplasm of the bacterial cells. Initial findings revealed at least one periplasmic protein
    [Show full text]
  • Harmful Cyanobacteria Blooms and Their Toxins In
    Harmful cyanobacteria blooms and their toxins in Clear Lake and the Sacramento-San Joaquin Delta (California) 10-058-150 Surface Water Ambient Monitoring Program (SWAMP) Prepared for: Central Valley Regional Water Quality Control Board 11020 Sun Center Drive, Suite 200 Rancho Cordova, CA 95670 Prepared by: Cécile Mioni (Project Director) & Raphael Kudela (Project co-Director) University of California, Santa Cruz - Institute of Marine Sciences Dolores Baxa (Project co-Director) University of California, Davis – School of Veterinary Medicine Contract manager: Meghan Sullivan Central Valley Regional Water Quality Control Board _________________ With technical contributions by: Kendra Hayashi (Project manager), UCSC Thomas Smythe (Field Officer) and Chris White, Lake County Water Resources Scott Waller (Field Officer) and Brianne Sakata, EMP/DWR Tomo Kurobe (Molecular Biologist), UCD David Crane (Toxicology), DFG-WPCL Kim Ward, SWRCB/DWQ Lenny Grimaldo (Assistance for Statistic Analyses), Bureau of Reclamation Peter Raimondi (Assistance for Statistic Analyses), UCSC Karen Tait, Lake County Health Office Abstract Harmful cyanobacteria and their toxins are growing contaminants of concern. Noxious toxins produced by HC, collectively referred as cyanotoxins, reduce the water quality and may impact the supply of clean water for drinking as well as the water quality which directly impacts the livelihood of other species including several endangered species. USEPA recently (May 29, 2008) made the decision to add microcystin toxins as an additional cause of impairment for the Klamath River, CA. However, harmful cyanobacteria are some of the less studied causes of impairment in California water bodies and their distribution, abundance and dynamics, as well as the conditions promoting their proliferation and toxin production are not well characterized.
    [Show full text]
  • Azolla-Anabaena Symbiosis : Its Physiology and Use in Tropical
    6. Azolla-Anabaena symbiosis - its physiology and use in tropical agriculture 1. WATANABE 1. Introduction Azolla is a water fem widely distributed in aquatic habitats like ponds, canals, and paddies in temperate and tropical regions. This plant has been of interest to botanists and Asian agronoTIÙsts because of its symbiotic association with a N2 ­ fIxing blue-green alga and rapid growth in nitrogen-defIcient habitats. Recently, the interest in this plant-alga association has been renewed by the demand for less fossil energy·dependent agricultural technology. Reviews on updatinginformation were made by Moore [20], Watanabe [42] ,and Lumpkin and Plucknett [19]. A bibliographic list was published by the Inter­ national Rice Research Institute [15] . 2. Biology and physiology of Azolla-alga relation Azolla belongs to the Azollaceae, a heterosporous free-floating fem, and is close to the family Salviniaceae. There are six extant species of Azolla (Table 1) and 25 fossil species are recorded [14]. These are divided into two subgenera: El{azolla, a New World azolla, and Rhizosperma. Species differentiation is based on the morphology of the sexual organ. The number of septa in the glochidia was used as a taxonomic tool to differentiate Euazolla. This criterion was questioned by taxonomists because of variations within a given species [10] . In the subgenus Rhizosperma, the glochidia are replaced by a root-like structure emerging from the massulae in the micro­ sporangium. In A. nilotica, neither the glochidia nor the root-lïke structure is present on the massulae (Fig. 1). Because the sporocarps are usually absent in naturally grown azolla, it is difft­ cult to identify species.
    [Show full text]
  • Biomass Production of Azolla Pinnata R
    Biomass production of Azzolla Pinnata R. BR. in contaminated soils of Punjab (India) Dr. Hardip Kaur* Department of Botany, S. D. College, Barnala-148 101. India. [email protected] Our modern agriculture is heavily dependent upon chemical fertilizers for increasing crop yield which slowly accumulated in the environment and pose a danger to the activity of many other organisms including man. More so, one of the constraints to high yields is the limited availability and high prices of N & P fertilizers. It has therefore became imperative to seek alternative to the chemical fertilizers through renewable organic sources which will not disturb ecology. Photosynthetic biofertilizers have drawn considerable attention to maintain the fertility status of soil. The conversion of molecular nitrogen into organic form by cynobacteria is considered today as one of the most direct method of utilization of solar energy and also considered as an extremely low cost biofertilizers. Azolla – Anabaena symbiotic system has proved to potential N- source in water logged rice ecosystem which is most effective when ploughed into the soil. The natural floating ‘nitrogen factory’ consists of two plants-the water fern Azolla and blue green alga Anabaena azollae living together in symbiotic association. The use of Azolla with its ‘nif’ genes receives considerable interest as an efficient biofertilizer. The algal symbiont Anabaena is harboured in the ventral side of the dorsal leaves of Azolla and remained present during all stages of frond development. It is very sensitive to the presence or absence of suitable concentration of nutrients and soil pH. Azolla grows well in alkaline soils.
    [Show full text]
  • A New and Three Rare Species of Planktonic Anabaena (Nostocales, Cyanophyta/Cyanobacteria) from Japan
    Bull. Natn. Sci. Mus., Tokyo, Ser. B, 32(3), pp. 109–116, September 22, 2006 A New and Three Rare Species of Planktonic Anabaena (Nostocales, Cyanophyta/Cyanobacteria) from Japan Masayuki Watanabe Department of Botany, National Science Museum, Amakubo 4–1–1, Tsukuba 305–0005, Japan E-mail: [email protected] Abstract A new species of planktonic Anabaena, A. tsugaruensis, is described from Lake Hig- urashi-no-ike of the Tsugaru-Juniko lakes in Aomori Prefecture, northern Japan. Further, three rare species of planktonic Anabaena, A. cf. heterospora Nyg., A. levanderi Lemm., and A. cf. solitaria Kleb., are added to the Japanese cyanophyte flora with taxonomic notes. Key words : new species, new records, Anabaena, plankton, Cyanophyta, Japan. Since Professor Okamura recorded planktonic Results and Discussions Anabaena, A. flos-aquae and A. spiroides var. crassa from Japanese waters for the first time Anabaena cf. heterospora Nygaard, 1949 (Okamura 1916), 25 planktonic species of the (Figs. 1–5) genus Anabaena have been recorded up to now. Trichomes free-floating, straight, constricted at The present author has recorded 20 planktonic the cross walls, delicately attenuated at the species of Anabaena including five new species apices. Cells barrel-shaped or shortly cylindrical, (A. akankoensis, A. citrispora, A. minispora, A. 3.2–3.8 mm wide, 2–6 mm long. Heterocytes oumiana, and A. pseudocompacta) from Japan spherical or cylindrical, 4.5–5 mm wide, 5–7 mm and proposed two new combinations (A. smithii long. Akinetes cylindrical, with rounded ends, and A. ucrainica) for the Japanese populations 5–6 mm wide, 10–23 mm long, usually near the (Watanabe 1985, 1992, 1996, 1996a, 1998, 2003, both side of the heterocytes.
    [Show full text]
  • The Study on the Cultivable Microbiome of the Aquatic Fern Azolla Filiculoides L
    applied sciences Article The Study on the Cultivable Microbiome of the Aquatic Fern Azolla Filiculoides L. as New Source of Beneficial Microorganisms Artur Banach 1,* , Agnieszka Ku´zniar 1, Radosław Mencfel 2 and Agnieszka Woli ´nska 1 1 Department of Biochemistry and Environmental Chemistry, The John Paul II Catholic University of Lublin, 20-708 Lublin, Poland; [email protected] (A.K.); [email protected] (A.W.) 2 Department of Animal Physiology and Toxicology, The John Paul II Catholic University of Lublin, 20-708 Lublin, Poland; [email protected] * Correspondence: [email protected]; Tel.: +48-81-454-5442 Received: 6 May 2019; Accepted: 24 May 2019; Published: 26 May 2019 Abstract: The aim of the study was to determine the still not completely described microbiome associated with the aquatic fern Azolla filiculoides. During the experiment, 58 microbial isolates (43 epiphytes and 15 endophytes) with different morphologies were obtained. We successfully identified 85% of microorganisms and assigned them to 9 bacterial genera: Achromobacter, Bacillus, Microbacterium, Delftia, Agrobacterium, and Alcaligenes (epiphytes) as well as Bacillus, Staphylococcus, Micrococcus, and Acinetobacter (endophytes). We also studied an A. filiculoides cyanobiont originally classified as Anabaena azollae; however, the analysis of its morphological traits suggests that this should be renamed as Trichormus azollae. Finally, the potential of the representatives of the identified microbial genera to synthesize plant growth-promoting substances such as indole-3-acetic acid (IAA), cellulase and protease enzymes, siderophores and phosphorus (P) and their potential of utilization thereof were checked. Delftia sp. AzoEpi7 was the only one from all the identified genera exhibiting the ability to synthesize all the studied growth promoters; thus, it was recommended as the most beneficial bacteria in the studied microbiome.
    [Show full text]