Article
Biochemistry & Molecular Biology
Benjamin L. Springstein, Dennis J. Nurnberg, Christian Woehle, Julia Weissenbach, Marius L. Theune, Andreas O. Helbig, Iris Maldener, Tal Dagan, Karina Stucken
Summary: Filament-forming proteins play crucial roles in cellular processes such as cell division and growth. Two novel coiled-coil-rich proteins in the filament-forming cyanobacterium Anabaena assemble into heteropolymers and function in maintaining the multicellular shape. Their function is achieved through cooperation with other proteins to stabilize the cell shape.
Article
Microbiology
Li Wang, Tian-Cai Niu, Ana Valladares, Gui-Ming Lin, Ju-Yuan Zhang, Antonia Herrero, Wen-Li Chen, Cheng-Cai Zhang
Summary: This study investigates the regulation of FtsZ during heterocyst differentiation, revealing that the interaction between PatD and FtsZ interferes with FtsZ assembly, affecting cell division and differentiation processes.
ENVIRONMENTAL MICROBIOLOGY
(2021)
Article
Biochemistry & Molecular Biology
Ryo Nagao, Makio Yokono, Yoshifumi Ueno, Yoshiki Nakajima, Takehiro Suzuki, Ka-Ho Kato, Naoki Tsuboshita, Naoshi Dohmae, Jian-Ren Shen, Shigeki Ehira, Seiji Akimoto
Summary: Heterocysts are formed in filamentous heterocystous cyanobacteria under nitrogen-starvation conditions and have a lower amount of photosystem II (PSII) complexes compared to vegetative cells. Investigations on heterocysts have shown almost no PSII complexes but the presence of PSI complexes in the thylakoids. Analysis of fluorescence spectra and excitation-energy-relaxation processes in heterocysts revealed differences in fluorescence characteristics of PSII and PSI compared to vegetative thylakoids.
BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS
(2022)
Article
Microbiology
Chao Li, He Zhang, Yaru Du, Wei Zhang, Xudong Xu
Summary: The gene patU, particularly the patU3 variant in filamentous cyanobacteria, is crucial for both heterocyst patterning and cell size control. The N-terminal 16-amino-acid sequence of PatU3 is essential for its interaction with the cell division protein Ftn6 and for determining cell size. Furthermore, certain peptides within this sequence can restore cell size in a patU3 deletion mutant, suggesting a potential role in intercellular coordination in cyanobacteria.
JOURNAL OF BACTERIOLOGY
(2021)
Article
Biology
Lei Yin, Zhenggao Zheng, Yilin Li, Xiying Li, Dan Cheng, Chunxia Dong, Yixuan Liu, Jindong Zhao
Summary: Spatial periodic signal based on Turing's principle is used to simulate cell differentiation in multicellular organisms. In the filamentous cyanobacterium Nostoc sp. PCC 7120, a dividing cell delays differentiation until completion of division, resulting in only one daughter cell becoming heterocyst. Mutants of patU3, an inhibitor of heterocyst formation, do not show this delay and form heterocyst pairs or dumbbell-shaped heterocysts from dividing cells or cells undergoing cytokinesis. PatA mutant restores intercalary heterocysts by a single nucleotide mutation of patU3, and double mutants of patU3/patA and patU3/hetF exhibit patU3 mutant phenotypes. HetF, which degrades PatU3, is recruited to the cell divisome through its C-terminal domain. A HetF mutant lacking the C-terminal domain fails to prevent heterocyst pair formation, indicating the importance of divisome recruitment of HetF for delaying differentiation in dividing cells. This study highlights the key role of PatU3 in cell-division coupled control of differentiation.
SCIENCE CHINA-LIFE SCIENCES
(2023)
Article
Biochemistry & Molecular Biology
Wei-Yue Xing, Jing Liu, Cheng-Cai Zhang
Summary: This study reveals the importance of HetF protein in the morphogenesis of heterocysts in the filamentous cyanobacterium Anabaena sp. PCC 7120. The absence of HetF protein allows heterocyst differentiation to initiate and proceed to the stage just before heterocyst envelope formation.
MOLECULAR MICROBIOLOGY
(2023)
Article
Biochemistry & Molecular Biology
Jorge Guio, Maria Teresa Bes, Monica Balsera, Laura Calvo-Begueria, Emma Sevilla, Maria Luisa Peleato, Maria F. Fillat
Summary: FurA is a multifunctional regulator in cyanobacteria that can develop disulfide reductase activity due to lack of a structural zinc ion. The interaction between FurA and the type m thioredoxin TrxA was confirmed through in vitro and in vivo studies, suggesting TrxA as a redox partner that modulates FurA performance in facilitating interactions with different ligands.
Article
Microbiology
Hannah Schaetzle, Sergio Arevalo, Leonard Fresenborg, Hans-Michael Seitz, Enrique Flores, Enrico Schleiff
Summary: In the model cyanobacterium Anabaena sp. strain PCC 7120, TonB proteins such as TonB3 are involved in transporting ferric schizokinen, while TonB2 mutations strongly influence outer membrane integrity. The different TonB proteins appear to have distinct functions and play important roles in cellular metal concentrations and antibiotic susceptibility.
Article
Microbiology
Qin-Xue Sun, Min Huang, Ju-Yuan Zhang, Xiaoli Zeng, Cheng-Cai Zhang
Summary: This study identified a two-component signaling system, composed of CdgK and CdgS, that regulates cell size in cyanobacteria. The GGDEF domain of CdgS was found to be essential in cell size control. This research provides insights into the mechanisms of cell size regulation in cyanobacteria.
MICROBIOLOGY SPECTRUM
(2023)
Article
Multidisciplinary Sciences
Wei-Yue Xing, Jing Liu, Ju-Yuan Zhang, Xiaoli Zeng, Cheng-Cai Zhang
Summary: In this study, a new negative regulator called PatU3 was identified in the prokaryote Anabaena, which regulates cell division and heterocyst development. The results showed that PatU3 is a specific substrate of the protease activity of HetF, and HetF controls cell division and heterocyst differentiation by controlling the inhibitory effects of PatU3.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Biology
Cristina Velazquez-Suarez, Ignacio Luque, Antonia Herrero
Summary: The cyanobacterium Anabaena sp. PCC 7120 forms filaments of communicating cells. Under nitrogen scarcity, some cells differentiate into heterocysts, allowing the oxygen-sensitive N-2-reduction system to be expressed and operated in oxic environments. Peptidoglycan plays a key role in heterocyst differentiation and intercellular communication. The Mre proteins are involved in regulating peptidoglycan growth, heterocyst neck formation, and maintenance of polar structures in mature heterocysts.
Article
Microbiology
T. V. Divya, Celin Acharya
Summary: In this study, we discovered a protein called AzuR that negatively regulates the metallothionein NmtA in cyanobacteria. We demonstrated that AzuR binds to the regulatory element of NmtA and that the presence of metal ions can disrupt this binding. Overexpression of AzuR in cyanobacteria increased their sensitivity to cadmium.
FRONTIERS IN MICROBIOLOGY
(2022)
Article
Microbiology
Hannah Schatzle, Sergio Arevalo, Enrique Flores, Enrico Schleiff
Summary: Cyanobacteria, such as Anabaena, exhibit spatial separation of nitrogen fixation and photosynthesis, with specialized cells called heterocysts playing a key role in nitrogen fixation. The novel protein SjdR is involved in septal structure remodeling and intercellular solute exchange, demonstrating its importance in cell communication and growth under nitrogen depletion. Calcium supplementation can compensate for impaired diazotrophic growth in the absence of SjdR, highlighting the crucial role of calcium in cell wall structure in cyanobacteria.
Article
Biology
Zi-Qian Wang, Yiling Yang, Ju-Yuan Zhang, Xiaoli Zeng, Cheng-Cai Zhang
Summary: A gene called trcR has been identified as a repressor for the transcription of the trn operon, which is activated under translational stress caused by antibiotics. Transcriptional and translational regulations play important roles in cell adaptation to environmental conditions.
COMMUNICATIONS BIOLOGY
(2023)
Article
Marine & Freshwater Biology
Zi-Qian Wang, Cheng-Cai Zhang
Summary: In this study, the authors demonstrate that the system responsible for modifying ANN-decoding tRNAs is involved in the sensitivity of cyanobacteria to the environmental neurotoxin BMAA. The study also reveals that both BMAA and inactivation of the t(6)A biosynthesis pathway affect translational fidelity and ribosome assembly. BMAA-resistant mutants screening is an effective method for gaining insight into the toxic mechanisms of BMAA.
AQUATIC TOXICOLOGY
(2022)
Article
Microbiology
Sergio Arevalo, Anja Nenninger, Mercedes Nieves-Morion, Antonia Herrero, Conrad W. Mullineaux, Enrique Flores
Summary: The study reveals that in cyanobacteria, intercellular communication is mediated through septal junctions and nanopores, with coordinated regulation of septal junctions observed in cell. Intercellular exchange in response to nitrogen deprivation, ammonium, and nitrate assimilation varies, indicating the importance of these structures in multicellular behavior of heterocyst-forming cyanobacteria.
Article
Multidisciplinary Sciences
Sergio Camargo, Dena Leshkowitz, Bareket Dassa, Vicente Mariscal, Enrique Flores, Joel Stavans, Rinat Arbel-Goren
Summary: Cell-cell communication plays a crucial role in multicellular organisms. Disruption of communication in septal protein mutants of Anabaena sp. PCC 7120 led to significant global changes in gene expression, particularly affecting genes related to carbon metabolism, with increased expression of genes encoding carbon uptake systems and photosynthetic apparatus components, as well as decreased expression of genes related to heterocyst differentiation and polysaccharide export.
Article
Microbiology
Sergio Arevalo, Enrique Flores
Summary: Our study revealed that in cyanobacteria like Anabaena, FraE is primarily involved in heterocyst maturation, while FraC and FraD play roles in forming large nanopores in heterocyst septa. Furthermore, a difference in nanopore size was found between heterocyst and vegetative cell septa, indicating variations in intercellular communication mechanisms within these cells.
JOURNAL OF BACTERIOLOGY
(2021)
Article
Biology
Rinat Arbel-Goren, Valentina Buonfiglio, Francesca Di Patti, Sergio Camargo, Anna Zhitnitsky, Ana Valladares, Enrique Flores, Antonia Herrero, Duccio Fanelli, Joel Stavans
Summary: The study on the circadian clock in Anabaena sp. PCC 7120 cells reveals significant synchronization and spatial coherence, as well as features such as regulated gene expression, cell-cell communication, and cell cycle control. Additionally, the transcriptional oscillations of key genes suggest a multi-level regulation system.
Article
Microbiology
Li Wang, Tian-Cai Niu, Ana Valladares, Gui-Ming Lin, Ju-Yuan Zhang, Antonia Herrero, Wen-Li Chen, Cheng-Cai Zhang
Summary: This study investigates the regulation of FtsZ during heterocyst differentiation, revealing that the interaction between PatD and FtsZ interferes with FtsZ assembly, affecting cell division and differentiation processes.
ENVIRONMENTAL MICROBIOLOGY
(2021)
Article
Microbiology
Hannah Schatzle, Sergio Arevalo, Enrique Flores, Enrico Schleiff
Summary: Cyanobacteria, such as Anabaena, exhibit spatial separation of nitrogen fixation and photosynthesis, with specialized cells called heterocysts playing a key role in nitrogen fixation. The novel protein SjdR is involved in septal structure remodeling and intercellular solute exchange, demonstrating its importance in cell communication and growth under nitrogen depletion. Calcium supplementation can compensate for impaired diazotrophic growth in the absence of SjdR, highlighting the crucial role of calcium in cell wall structure in cyanobacteria.
Article
Microbiology
Mercedes Nieves-Morion, Enrique Flores, Martin J. Whitehouse, Aurelien Thomen, Rachel A. Foster
Summary: The study investigated single-cell C and N-2 fixation and metabolic dynamics along filaments in the model heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120 using stable isotopes and imaging techniques. The results revealed a substantial variability of metabolic states in wild-type filaments in culture, demonstrating the unpredicted heterogeneity of cellular metabolic activity.
Letter
Microbiology
Enrique Flores
Article
Microbiology
Hannah Schaetzle, Sergio Arevalo, Leonard Fresenborg, Hans-Michael Seitz, Enrique Flores, Enrico Schleiff
Summary: In the model cyanobacterium Anabaena sp. strain PCC 7120, TonB proteins such as TonB3 are involved in transporting ferric schizokinen, while TonB2 mutations strongly influence outer membrane integrity. The different TonB proteins appear to have distinct functions and play important roles in cellular metal concentrations and antibiotic susceptibility.
Article
Microbiology
Enrique Flores, Dwight K. Romanovicz, Mercedes Nieves-Morion, Rachel A. Foster, Tracy A. Villareal
Summary: In this study, an electron microscopy analysis revealed the unique cellular structures and adaptations of the symbiosis between Hemiaulus hauckii and Richelia intracellularis, including the presence of three to four vegetative cells and one heterocyst. The study also identified the specialized heterocyst envelope structure of R. intracellularis and the potential pathway for transferring fixed nitrogen to the diatom's cytoplasm.
FRONTIERS IN MICROBIOLOGY
(2022)
Article
Microbiology
Cristina Velazquez-Suarez, Ana Valladares, Ignacio Luque, Antonia Herrero
Summary: Peptidoglycan growth in bacteria is essential for their morphology and survival. Recent studies have revealed that the patterns of peptidoglycan growth are more diverse than previously thought. Anabaena, a filamentous bacterium, exhibits features of multicellular organisms and has a unique pattern of continuous peptidoglycan incorporation at the intercellular regions. This pattern contributes to the assembly and maintenance of protein complexes involved in intercellular molecular exchange.
Article
Multidisciplinary Sciences
Mercedes Nieves-Morion, Sergio Camargo, Sepehr Bardi, Maria Teresa Ruiz, Enrique Flores, Rachel A. Foster
Summary: Certain diatoms thrive in low-nutrient waters of the open ocean by forming a close association with N-2-fixing cyanobacteria. In one such symbiotic relationship, the endosymbiont R. euintracellularis lives inside the host H. hauckii and plays a role in N-2 fixation. The function of proteins from R. euintracellularis was identified through heterologous gene expression experiments.
Article
Microbiology
Rinat Arbel-Goren, Bareket Dassa, Anna Zhitnitsky, Ana Valladares, Antonia Herrero, Enrique Flores, Joel Stavans
Summary: This study investigates the dynamics of circadian clock-controlled gene expression in the multicellular cyanobacterium Anabaena under nitrogen-stress conditions. The results show that circadian clock synchronization is limited to contiguous photosynthetic cells in nitrogen-deprived conditions, and heterocyst differentiation occurs preferentially within a limited time window during the circadian clock period. Furthermore, the absence of the circadian clock core components affects nitrogen fixation rather than early or mid-heterocyst differentiation genes.