scholarly journals PII Is Important in Regulation of Nitrogen Metabolism but Not Required for Heterocyst Formation in the Cyanobacterium Anabaena sp. PCC 7120

2007 ◽  
Vol 282 (46) ◽  
pp. 33641-33648 ◽  
Author(s):  
Ying Zhang ◽  
Hai Pu ◽  
Qingsong Wang ◽  
Shu Cheng ◽  
Weixing Zhao ◽  
...  
Keyword(s):  
Nitrogen Metabolism ◽  
Nitrate Uptake ◽  
Nitrogenase Activity ◽  
Tyrosine Nitration ◽  
Wild Type ◽  
Cyanobacterium Anabaena ◽  
In The Wild ◽  
Anabaena Sp ◽  
Key Residues ◽  
Pcc 7120

PII is an important signal protein for regulation of nitrogen metabolism in bacteria and plants. We constructed a mutant of glnB, encoding PII, in a heterocystous cyanobacterium, Anabaena sp. PCC 7120, with a cre-loxP system. The mutant (MP2α) grew more slowly than the wild type under all nitrogen regimens. It excreted a large amount of ammonium when grown on nitrate due to altered activities of glutamine synthetase and nitrate reductase. MP2α had a low nitrogenase activity but was able to form heterocysts under diazotrophic conditions, suggesting that PII is not required for heterocyst differentiation. Analysis of the PII with mass spectroscopy found tyrosine nitration at Tyr-51 under diazotrophic conditions while no phosphorylation at Ser-49 was detected. The strains 51F and 49A, which have PII with mutations of Y51F and S49A, respectively, were constructed to analyze the functions of the two key residues on the T-loop. Like MP2α, they had low nitrogenase activity and grew slowly under diazotrophic conditions. 49A was also impaired in nitrate uptake and formed heterocysts in the presence of nitrate. The up-regulation of ntcA after nitrogen step-down, which was present in the wild type, was not observed in 51F and 49A. While our results showed that the Ser-49 residue is important to the function of PII in Anabaena sp. PCC 7120, evidence from the PII pattern of the wild type and 49A in non-denaturing gel electrophoresis suggested that Ser-49 is not modified. The possible physiological roles of tyrosine nitration of PII are discussed.

scholarly journals Heterocyst Development and Diazotrophic Metabolism in Terminal Respiratory Oxidase Mutants of the Cyanobacterium Anabaena sp. Strain PCC 7120

2007 ◽  
Vol 189 (12) ◽  
pp. 4425-4430 ◽  
Author(s):  
Ana Valladares ◽  
Iris Maldener ◽  
Alicia M. Muro-Pastor ◽  
Enrique Flores ◽  
Antonia Herrero
Keyword(s):  
Nitrogenase Activity ◽  
Nitrogen Deprivation ◽  
Wild Type ◽  
Cyanobacterium Anabaena ◽  
In The Wild ◽  
Membrane Reorganization ◽  
Respiratory Oxidases ◽  
And Performance ◽  
Pcc 7120 ◽  
Heterocyst Development

ABSTRACT Heterocyst development was analyzed in mutants of the heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120 bearing inactivated cox2 and/or cox3 genes, encoding heterocyst-specific terminal respiratory oxidases. At the morphological level, the cox2 cox3 double mutant (strain CSAV141) was impaired in membrane reorganization involving the so-called honeycomb system that in the wild-type strain is largely or exclusively devoted to respiration, accumulated glycogen granules at conspicuously higher levels than the wild type (in both vegetative cells and heterocysts), and showed a delay in carboxysome degradation upon combined nitrogen deprivation. Consistently, chemical analysis confirmed higher accumulation of glycogen in strain CSAV141 than in the wild type. No impairment was observed in the formation of the glycolipid or polysaccharide layers of the heterocyst envelope, consistent with the chemical detection of heterocyst-specific glycolipids, or in the expression of the heterocyst-specific genes nifHDK and fdxH. However, nitrogenase activity under oxic conditions was impaired in strain CSAV135 (cox3) and undetectable in strain CSAV141 (cox2 cox3). These results show that these dedicated oxidases are required for normal development and performance of the heterocysts and indicate a central role of Cox2 and, especially, of Cox3 in the respiratory activity of the heterocysts, decisively contributing to protection of the N2 fixation machinery against oxygen. However, in contrast to the case for other diazotrophic bacteria, expression of nif genes in Anabaena seems not to be affected by oxygen.

scholarly journals A TRAP Transporter for Pyruvate and Other Monocarboxylate 2-Oxoacids in the Cyanobacterium Anabaena sp. Strain PCC 7120

2010 ◽  
Vol 192 (22) ◽  
pp. 6089-6092 ◽  
Author(s):  
Rafael Pernil ◽  
Antonia Herrero ◽  
Enrique Flores
Keyword(s):  
Open Reading Frames ◽  
Wild Type ◽  
Cyanobacterium Anabaena ◽  
Anabaena Sp ◽  
Significant Uptake ◽  
Pcc 7120 ◽  
Reading Frames ◽  
T System

ABSTRACT In the cyanobacterium Anabaena sp. strain PCC 7120, open reading frames (ORFs) alr3026, alr3027, and all3028 encode a tripartite ATP-independent periplasmic transporter (TRAP-T). Wild-type filaments showed significant uptake of [14C]pyruvate, which was impaired in the alr3027 and all3028 mutants and was inhibited by several monocarboxylate 2-oxoacids, identifying this TRAP-T system as a pyruvate/monocarboxylate 2-oxoacid transporter.

scholarly journals hetL Overexpression Stimulates Heterocyst Formation in Anabaena sp. Strain PCC 7120

2002 ◽  
Vol 184 (24) ◽  
pp. 6873-6881 ◽  
Author(s):  
Duan Liu ◽  
James W. Golden
Keyword(s):  
Null Mutant ◽  
Wild Type ◽  
Heterologous Promoter ◽  
Repeat Proteins ◽  
Overexpression Strain ◽  
In The Wild ◽  
Anabaena Sp ◽  
Pcc 7120 ◽  
Diazotrophic Growth ◽  
Heterocyst Development

ABSTRACT The cyanobacterium Anabaena sp. strain PCC 7120 forms single heterocysts about every 10 to 15 vegetative cells along filaments. PatS is thought to be a peptide intercellular signal made by developing heterocysts that prevents neighboring cells from differentiating. Overexpression of the patS gene suppresses heterocyst formation. The hetL gene (all3740) was isolated in a genetic screen to identify genes involved in PatS signaling. Extracopy hetL allowed heterocyst formation in a patS overexpression strain. hetL overexpression from a heterologous promoter in wild-type Anabaena PCC 7120 induced multiple-contiguous heterocysts (Mch) in nitrate-containing medium. The predicted HetL protein is composed almost entirely of pentapeptide repeats with a consensus of A(D/N)L*X, where * is a polar amino acid. Thirty Anabaena PCC 7120 genes contain this repeat motif. A synthetic pentapeptide corresponding to the last 5 amino acids of PatS, which suppresses heterocyst formation in the wild type, did not suppress heterocyst formation in a hetL overexpression strain, indicating that HetL overexpression is affecting heterocyst regulation downstream of PatS production. The transcription regulator NtcA is required for the initiation of heterocyst formation. hetL overexpression allowed the initiation of heterocyst development in an ntcA-null mutant, but differentiation was incomplete. hetR and hetC mutations that block heterocyst development are epistatic to hetL overexpression. A hetL-null mutant showed normal heterocyst development and diazotrophic growth, which could indicate that it is not normally involved in regulating development, that it normally plays a nonessential accessory role, or perhaps that its loss is compensated by cross talk or redundancy with other pentapeptide repeat proteins.

scholarly journals ThetrpEGene Negatively Regulates Differentiation of Heterocysts at the Level of Induction in Anabaena sp. Strain PCC 7120

2014 ◽  
Vol 197 (2) ◽  
pp. 362-370 ◽  
Author(s):  
Patrick Videau ◽  
Loralyn M. Cozy ◽  
Jasmine E. Young ◽  
Blake Ushijima ◽  
Reid T. Oshiro ◽  
...  
Keyword(s):  
Repeat Sequence ◽  
Mutant Phenotype ◽  
Wild Type ◽  
Content Type ◽  
Type Pattern ◽  
In The Wild ◽  
Anabaena Sp ◽  
Pcc 7120

Levels of 2-oxoglutarate (2-OG) reflect nitrogen status in many bacteria. In heterocystous cyanobacteria, a spike in the 2-OG level occurs shortly after the removal of combined nitrogen from cultures and is an integral part of the induction of heterocyst differentiation. In this work, deletion of one of the two annotatedtrpEgenes inAnabaenasp. strain PCC 7120 resulted in a spike in the 2-OG level and subsequent differentiation of a wild-type pattern of heterocysts when filaments of the mutant were transferred from growth on ammonia to growth on nitrate. In contrast, 2-OG levels were unaffected in the wild type, which did not differentiate under the same conditions. An inverted-repeat sequence located upstream oftrpEbound a central regulator of differentiation, HetR,in vitroand was necessary for HetR-dependent transcription of a reporter fusion and complementation of the mutant phenotypein vivo. Functional complementation of the mutant phenotype with the addition of tryptophan suggested that levels of tryptophan, rather than the demonstrated anthranilate synthase activity of TrpE, mediated the developmental response of the wild type to nitrate. A model is presented for the observed increase in 2-OG in thetrpEmutant.

scholarly journals Septum-Localized Protein Required for Filament Integrity and Diazotrophy in the Heterocyst-Forming Cyanobacterium Anabaena sp. Strain PCC 7120

2007 ◽  
Vol 189 (10) ◽  
pp. 3884-3890 ◽  
Author(s):  
Enrique Flores ◽  
Rafael Pernil ◽  
Alicia M. Muro-Pastor ◽  
Vicente Mariscal ◽  
Iris Maldener ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Nitrogenase Activity ◽  
Early Stage ◽  
Vegetative Cells ◽  
Reading Frame ◽  
Cyanobacterium Anabaena ◽  
In The Wild ◽  
Z Ring ◽  
Green Fluorescent ◽  
Pcc 7120

ABSTRACT Heterocysts, formed when filamentous cyanobacteria, such as Anabaena sp. strain PCC 7120, are grown in the absence of combined nitrogen, are cells that are specialized in fixing atmospheric nitrogen (N2) under oxic conditions and that transfer fixed nitrogen to the vegetative cells of the filament. Anabaena sp. mutants whose sepJ gene (open reading frame alr2338 of the Anabaena sp. genome) was affected showed filament fragmentation and arrested heterocyst differentiation at an early stage. In a sepJ insertional mutant, a layer similar to a heterocyst polysaccharide layer was formed, but the heterocyst-specific glycolipids were not synthesized. The sepJ mutant did not exhibit nitrogenase activity even when assayed under anoxic conditions. In contrast to proheterocysts produced in the wild type, those produced in the sepJ mutant still divided. SepJ is a multidomain protein whose N-terminal region is predicted to be periplasmic and whose C-terminal domain resembles an export permease. Using a green fluorescent protein translationally fused to the carboxyl terminus of SepJ, we observed that in mature heterocysts and vegetative cells, the protein is localized at the intercellular septa, and when cell division starts, it is localized in a ring whose position is similar to that of a Z ring. SepJ is a novel composite protein needed for filament integrity, proper heterocyst development, and diazotrophic growth.

Expanding the Natural Products Heterologous Expression Repertoire in the Model Cyanobacterium Anabaena sp. Strain PCC 7120: Production of Pendolmycin and Teleocidin B-4

2019 ◽  
Author(s):  
Patrick Videau ◽  
Kaitlyn Wells ◽  
Arun Singh ◽  
Jessie Eiting ◽  
Philip Proteau ◽  
...  
Keyword(s):  
Natural Products ◽  
Genome Mining ◽  
Gene Clusters ◽  
Combinatorial Biosynthesis ◽  
Test Case ◽  
Biosynthetic Gene ◽  
Biosynthetic Gene Clusters ◽  
Cyanobacterium Anabaena ◽  
Anabaena Sp ◽  
Pcc 7120

Cyanobacteria are prolific producers of natural products and genome mining has shown that many orphan biosynthetic gene clusters can be found in sequenced cyanobacterial genomes. New tools and methodologies are required to investigate these biosynthetic gene clusters and here we present the use of <i>Anabaena </i>sp. strain PCC 7120 as a host for combinatorial biosynthesis of natural products using the indolactam natural products (lyngbyatoxin A, pendolmycin, and teleocidin B-4) as a test case. We were able to successfully produce all three compounds using codon optimized genes from Actinobacteria. We also introduce a new plasmid backbone based on the native <i>Anabaena</i>7120 plasmid pCC7120ζ and show that production of teleocidin B-4 can be accomplished using a two-plasmid system, which can be introduced by co-conjugation.

Target Gene Inactivation in Cyanobacterium Anabaena sp. PCC 7120

BIO-PROTOCOL ◽  
2016 ◽  
Vol 6 (15) ◽  
Author(s):  
Kangming Chen ◽  
Huilan Zhu ◽  
Liping Gu ◽  
Shengni Tian ◽  
Ruanbao Zhou
Keyword(s):  
Target Gene ◽  
Gene Inactivation ◽  
Cyanobacterium Anabaena ◽  
Anabaena Sp ◽  
Pcc 7120
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