Cyanobacterial System Research Articles

Molecular modeling of abc transporter system — permease proteins from Microcoleus chthonoplastes PCC 7420 for effective binding against secreted aspartyl proteinases in Candida albicans — A therapeutic intervention

Secreted aspartyl proteinases (SAP) are the key virulence factors that play a central role in the pathogenesis of Candida albicans and always are the best target for designing potent antifungal agents. Cyanobacteria have already been recognized to provide chemical and pharmacological novelty and diversity over conventional sources of drugs for combating major diseases ranging from AIDS to cancer. In this study, the two ABC transporter systems - permease proteins from Microcoleus chthonoplastes PCC 7420 were modeled and the protein-protein interaction assessment of the modeled proteins with selective secreted aspartyl proteinases of Candida albicans was attempted. The modeled proteins were assigned PMDB IDs PM0077423 and PM0077424. The secreted aspartyl protease 5 of Candida albicans showed effective interaction with ABC transporter permease protein 2 of Microcoleus chthonoplastes PCC 7420. Hydrophobic interactions were found between Tyr, Phe and Pro in chain A and Pro and Tyr in chain B. Our results of the docked complexes clearly demonstrated the potentiality of permease proteins in arresting the virulence nature of SAP of Candida albicans effectively. This study is first of its kind in addressing the therapeutic intervention of virulence nature of Candida albicans by the cyanobacterial system.

(2195) Proposal to conserve the name Gloeothece (Cyanophyceae) with a conserved type

TAXONVolume 62, Issue 5 p. 1056-1056 Proposals to Conserve or Reject NamesFree Access (2195) Proposal to conserve the name Gloeothece (Cyanophyceae) with a conserved type Jan Mareš, Corresponding Author Jan Mareš mares@butbncas.cz University of South Bohemia, Faculty of Science, Branišovká 31, České Budějovice, 37005 Czech RepublicSearch for more papers by this authorTomáš Hauer, Tomáš Hauer University of South Bohemia, Faculty of Science, Branišovká 31, České Budějovice, 37005 Czech Republic Academy of Sciences of the Czech Republic, Institute of Botany, Dukelská 135, Třeboň, 37982 Czech Republic;Search for more papers by this authorJiří Komárek, Jiří Komárek University of South Bohemia, Faculty of Science, Branišovká 31, České Budějovice, 37005 Czech Republic Academy of Sciences of the Czech Republic, Institute of Botany, Dukelská 135, Třeboň, 37982 Czech Republic;Search for more papers by this authorPierre Compère, Pierre Compère National Botanic Garden of Belgium, Domein van Bouchout, Meise, 1860 BelgiumSearch for more papers by this author Jan Mareš, Corresponding Author Jan Mareš mares@butbncas.cz University of South Bohemia, Faculty of Science, Branišovká 31, České Budějovice, 37005 Czech RepublicSearch for more papers by this authorTomáš Hauer, Tomáš Hauer University of South Bohemia, Faculty of Science, Branišovká 31, České Budějovice, 37005 Czech Republic Academy of Sciences of the Czech Republic, Institute of Botany, Dukelská 135, Třeboň, 37982 Czech Republic;Search for more papers by this authorJiří Komárek, Jiří Komárek University of South Bohemia, Faculty of Science, Branišovká 31, České Budějovice, 37005 Czech Republic Academy of Sciences of the Czech Republic, Institute of Botany, Dukelská 135, Třeboň, 37982 Czech Republic;Search for more papers by this authorPierre Compère, Pierre Compère National Botanic Garden of Belgium, Domein van Bouchout, Meise, 1860 BelgiumSearch for more papers by this author First published: 30 December 2018 https://doi.org/10.12705/625.24Citations: 3AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume62, Issue5October 2013Pages 1056-1056 RelatedInformation

Phenotypic and ecological diversity of freshwater coccoid cyanobacteria from maritime Antarctica and islands of NW Weddell Sea. I. Synechococcales.

The review of freshwater natural populations of coccoid cyanobacteria from the ecosystems of the coastal Antarctica in the vicinity of Antarctic Peninsula is presented in two consequent articles. The natural cyanobacterial populations were studied from deglaciated regions with aquatic and terrestrial habitats, mainly from the islands Nelson and King George (South Shetland Islands) and from the northern deglaciated part of the James Ross Island (NW part of the Weddell Sea). Majority of identified morphospecies was distinctly ecologically restricted and their cultivation was not successful; the molecular evaluation was therefore not possible. All morphotypes appeared also in small quantities, and only few morphospecies created locally more intense populations. However, the knowledge of phenotype variation is important for the classification of Antarctic cyanobacterial diversity. This first article contains 11 taxa (morphospecies) from 9 genera from the simple phylogenetic clade, classified recently in the order Synechococcales (the second part will contain species from more complicated unicellular cyanobacterial orders). Our results were compared with literary data, but several populations occurred only rarely in atypical stages and their taxonomic classification was difficult. The modern cyanobacterial system (Hoffmann et al. 2005, Komárek et al. 2013) is used for the classification.

Cyanobacterial Timing System Differs from Those in Eukaryotes

Although circadian clocks were thought to be found only among eukaryotes, bacteria are also endowed with 24-hour timing systems, according to Susan Golden from the University of California in San Diego. “Photosynthetically growing cyanobacteria, for example, have a group of interacting proteins, KaiA, KaiB, and KaiC, at the heart of their circadian clock and kinases that help set the clock as well as transmit temporal information to its regulating genes,” she says. Golden described the system during a public lecture at Rockefeller University in New York, N.Y., last November.

Photosynthesis driven conversion of carbon dioxide to fatty alcohols and hydrocarbons in cyanobacteria

The production of high value biochemicals and high energy biofuels from sustainable resources through the use of microbial based, green conversion technologies could reduce the dependence on petrochemical resources. However, a sustainable source of carbon and a clean, cost effective method for its conversion to high quality biofuel products are obstacles that must be overcome. Here we describe the biosynthesis of fatty alcohols in a genetically engineered cyanobacterial system through heterologously expressing fatty acyl-CoA reductase and the effect of environmental stresses on the production of fatty alcohols in the mutant strains. Hydrocarbon production in three representative types of native cyanobacterial model strains and the mutant strain overexpressing acetyl-CoA carboxylase was evaluated. The results of this investigation demonstrate the potential for direct production of high value chemicals and high energy fuels in a single biological system that utilizes solar energy as the energy source and carbon dioxide as the carbon source.

An attempt to reveal a role of a transcription/translation feedback loop in the cyanobacterial KaiC protein-based circadian system by using a semi-synthetic method

The use of synthetic biology to design artificial gene circuits is an important approach for understanding the principles underlying the complicated dynamic behaviours of biomolecular networks, such as genetic switching and biological rhythms. The synthetic approach is also useful in systems biology in that it can be used to create artificial bypasses for processes related to cellular phenomena of interest for their easier analysis. To validate the role of transcription feedback in the cyanobacterial circadian system, we propose an experimental design for a 'semi-synthetic' approach that involves transplantation of the kaiABC genes into Escherichia coli and the construction of chimeric transcriptional outputs. The design principle and preliminary results are discussed.

Cyanobacteria respond to cytokinin

We studied the effects of trans-zeatin (10−9–10−5 M) on the RNA synthesis in the in vitro transcriptional system containing DNA and RNA polymerase of a cyanobacterium Synechocystis sp. PCC 6803. The cytokinin enhanced transcription in this system, and its action depended on the concentration applied: trans-zeatin exerted its highest effects at the concentrations of 10−8–10−6 M. Adenine, which derivatives are trans-zeatin and other purine cytokinins, did exert such an effect. Its wide range of concentrations (10−7–10−4 M) did not affect 3H-UMP incorporation into RNA. This indicates a specificity of trans-zeatin action. Culturing of cyanobacteria for 3 days in the presence of synthetic cytokinin benzyladenine (10−6 M) also enhanced 3H-UMP incorporation into RNA. A cytokinin-binding protein isolated earlier from plant chloroplasts, which is involved in the cytokinin-dependent control of chloroplastic transcription, enhanced substantially the response of the cyanobacterial transcriptional system to cytokinin. The results obtained show that cyanobacteria, evolutionary ancestors of chloroplasts, own the system of cytokinin signal recognition, which might be transferred to the plant cell. This inspires further investigation of the systems of cytokinin signal perception and transduction in cyanobacteria and elucidation of common and different traits of these systems in plants and cyanobacteria.

Molecular Evolution of ldpA, a Gene Mediating the Circadian Input Signal in Cyanobacteria

The ldpA gene is an element of the cyanobacterial circadian system and mediates input to the clock. Using complete prokaryotic genomes from various public databases, I analyzed the structure and phylogeny of the ldpA genes. This gene belongs to the large superfamily of ferredoxins and has a HycB domain as a core element of its structure. In addition to this domain, ldpA has two conserved terminal domains that are specific to this gene and have no homologs in the databases. All three domains are under different selective constraints. The ldpA tree topology features two very distinct clades that are essentially the same as those in the previously reported trees of the sasA gene and the kaiBC operon, two other elements of the circadian system. The data on the ldpA polymorphism and evolutionary patterns give further support to the existence of two types of the system, kaiABC- and kaiBC-based, respectively. Each type has specific functional and selective constraints, which have likely been attained through highly concordant evolution of the system's components.

The accumulation and degradation dynamics of cyanophycin in cyanobacteria grown in symbiotic associations with plant tissues and cells

Five different artificial associations of cyanobacterial cells with the cells or tissues of nightshade and rauwolfia were studied. The associations grown on nitrogen-containing media produced heterocysts. Cyanobacterial cells in the associations retained their ability to take up bound nitrogen from the medium, to store it in the form of cyanophycin granules, and to use them in the process of symbiotic growth. The synthesis and degradation of cyanophycin granules in cyanobacterial cells were more active in the associations than in monocultures. In the symbiotic associations of Chlorogloeopsis fritschii ATCC 27193 with Solanum laciniatum cells and of Nostoc muscorum CALU 304 with the Rauwolfia serpentina callus, heterocysts were produced at 3- to 30-fold higher cyanophycin contents than in cyanobacterial monocultures. In contrast, in the association of N. muscorum CALU 304 with the Solanum dulcamara callus, heterocysts were produced at lower cyanophycin contents than in the N. muscorum CALU 304 monoculture. The degradation of cyanophycin granules in N. muscorum CALU 304 cells grown in associations with plant tissues or cells was subjected to mathematical analysis. The activation of cyanophycin degradation and heterocyst production in the associations N. muscorum CALU 304-R. serpentina and C. fritschii-S. laciniatum was accompanied by an enhanced synthesis of the nitrogen-containing alkaloids in plant cells. The data obtained suggest that an integrated system of nitrogen homeostasis can be formed in symbiotic associations. Depending on the growth stage of an association, its plant member can either stimulate the accumulation of bound nitrogen in vegetative cyanobacterial cells in the form of cyanophycin granules, or activate their degradation, or initiate the formation of heterocysts independently of the cyanobacterial sensory-signalling system.

シアノバクテリアの概日システムの解析

シアノバクテリアの概日システムの解析

The barbamide biosynthetic gene cluster: a novel marine cyanobacterial system of mixed polyketide synthase (PKS)-non-ribosomal peptide synthetase (NRPS) origin involving an unusual trichloroleucyl starter unit

Barbamide was extracted from the marine cyanobacterium Lyngbya majuscula strain 19L as a chlorinated lipopeptide for its potent molluscicidal activity. Precursor incorporation studies indicated that it is derived from acetate, l-phenylalanine, l-leucine and l-cysteine. The gene cluster responsible for biosynthesis of barbamide (bar) was cloned and characterized in this study. DNA sequence analysis of cosmid pLM49 revealed a cluster of 12 open reading frames (barA–barK) extending 26 kb including the expected polyketide synthase and non-ribosomal peptide synthetase modules and tailoring genes. The genetic architecture and domain organization of the bar cluster supports the assignment based on the apparent co-linearity of the systems. The activity assay of adenylation domains of barD (AD), barE (AE) and barG (AG2 for module 2) in an amino acid-dependent ATP-pyrophosphate exchange experiment supports the conclusion that barbamide is synthesized from acetate, l-phenylalanine, l-cysteine and l-leucine with trichloroleucine as a direct precursor by a mixed polyketide synthase/non-ribosomal polypeptide synthetase. Assembly of barbamide includes unique biochemical mechanisms for chlorination, one-carbon truncation during chain elongation, E-double bond formation and thiazole ring formation.

Nitrogen control in cyanobacteria.

Nitrogen is a quantitatively important bioelement which is incorporated into the biosphere through assimilatory processes carried out by microorganisms and plants. Numerous nitrogencontaining compounds can be used by different organisms as sources of nitrogen. These include, for instance, inorganic ions like nitrate or ammonium and simple organic compounds like urea, amino acids, and some nitrogen-containing bases. Additionally, many bacteria are capable of fixing N 2. Nitrogen control is a phenomenon that occurs widely among microorganisms and consists of repression of the pathways of assimilation of some nitrogen sources when some other, more easily assimilated source of nitrogen is available to the cells. Ammonium is the preferred nitrogen source for most bacteria, but glutamine is also a very good source of nitrogen for many microorganisms. Two thoroughly investigated nitrogen control systems are the NtrB-NtrC two-component regulatory system found in enterics and some other proteobacteria (80) and the GATA family global nitrogen control transcription factors of yeast and some fungi (75). Novel nitrogen control systems have, however, been identified in bacteria other than the proteobacteria, like Bacillus subtilis (26), Corynebacterium glutamicum (52), and the cyanobacteria. The cyanobacterial system is the subject of this review. The cyanobacteria are prokaryotes that belong to the Bacteria domain and are characterized by the ability to perform oxygenic photosynthesis. Cyanobacteria have a wide ecological distribution, and they occupy a range of habitats, which includes vast oceanic areas, temperate soils, and freshwater lakes, and even extreme habitats like arid deserts, frigid lakes, or hot springs. Photoautotrophy, fixing CO 2 through the Calvin cycle, is the dominant mode of growth of these organisms (109). A salient feature of the intermediary metabolism of cyanobacteria is their lack of 2-oxoglutarate dehydrogenase (109). As a consequence, they use 2-oxoglutarate mainly as a substrate for the incorporation of nitrogen, a metabolic arrangement that may have regulatory consequences. Notwithstanding their rather homogeneous metabolism, cyanobacteria exhibit remarkable morphological diversity, being found as either unicellular or filamentous forms and exhibiting a number of cell differentiation processes, some of which take place in response to defined environmental cues, as is the case for the differentiation of N 2-fixing heterocysts (109). Nitrogen control in cyanobacteria is mediated by NtcA, a transcriptional regulator which belongs to the CAP (the catabolite gene activator or cyclic AMP [cAMP] receptor protein) family and is therefore different from the well-characterized Ntr system. Interestingly, however, the signal transduction P II protein, which plays a key role in Ntr regulation, is found in cyanobacteria but with characteristics which differentiate it from proteobacterial P II. In the following paragraphs, we shall first briefly summarize our current knowledge of the cyanobacterial nitrogen assimilation pathways and of what is known about their regulation at the protein level. This description will introduce most of the known cyanobacterial nitrogen assimilation genes. We shall then describe the ntcA gene and the NtcA protein themselves to finally discuss NtcA function through a survey of the NtcA-regulated genes which participate in simple nitrogen assimilation pathways or in heterocyst differentiation and function.

Expression of a higher plant light-harvesting chlorophyll a/b-binding protein in Synechocystis sp. PCC 6803.

A chimeric lhcb gene, coding for Lhcb, a higher plant chlorophyll a/b-binding light-harvesting complex of photosystem II (LHCII), was constructed using the Synechocystis sp. PCC 6803 psbA3 promoter and a modified lhcb gene from pea. This construct drives synthesis of full-length, mature Lhcb under the control of the strong psbA3 promoter that usually drives expression of the D1 protein of photosystem II. This chimeric gene was transformed into a photosystem I-less/chlL(-) Synechocystis sp. PCC 6803 strain that is unable to synthesize chlorophyll in darkness. In the resulting strain, a high level of lhcb transcript was detected and transcript accumulation was enhanced by addition of exogenous Zn-chlorophyllide b. The chimeric lhcb gene was translated to produce full-length Lhcb as demonstrated by pulse-labeling: a new radioactively labeled band of a size corresponding to full-length Lhcb was visible on autoradiograms. Using Triton X-114 phase fractionation, this labeled protein band was found to partition to the phase containing integral membrane proteins, indicating that the pulse-labeled Lhcb is readily integrated into the membrane. However, Lhcb was rapidly degraded and did not accumulate in thylakoid membranes to levels that were detectable other than by pulse labeling. Upon immunological detection with LHCII antibodies, a small protein (approximately 8 kDa) was found specifically in the lhcb-containing mutant. We interpret this protein to be a degradation product of the full-length Lhcb. This fragment was stabilized by supplementing cells with xanthophylls, which incorporated into thylakoid membranes only in the mutant carrying lhcb. The lutein/chlorophyll ratio of thylakoids of this mutant was about 1 : 10. These results indicate that in this cyanobacterial system Lhcb is synthesized, integrated into the membrane, and then degraded to a approximately 8 kDa fragment that is stabilized by pigment binding and does not require the presence of chlorophyll b.

REGULATION OF PHOTOSYNTHETIC ENZYMES IN LIGHT- OR DARK-GROWN CYNANOBACTERIUM NOSTOC SP. MAC.

Cyanobacteria, like higher plant chloroplasts, must deal with the demands of diurnal metabolism. Carbohydrate, made in the light by the reductive pentose phosphate cycle, is catabolised at night mainly by the oxidative pentose phosphate pathway. The fedoxin-thioredoxin system is important in regulating these competing pathways in chloroplasts. The vicinal disulphide of thioredoxin is reduced by photosynthetic electron transport in the light [ I ] . This in turn activates several enzymes of the Calvin cycle and deactivates Glucose 6-phosphate dehydrogenase (G6PDH), the enzyme controlling entry of carbohydrates to the oxidative pentose phosphate pathway. At night, in the dark, thioredoxin is largely oxidised reversing the activity state of the two pathways. We recently provided a direct demonstration of lightactivatioddark-deactivation of several Calvin cycle enzymes both in Nosroc sp. Mac [2] and Synechocysris PCC 6803 [3], presumed to reflect regulation by the thioredoxin system. No significant G6PDH activity was detected in the light or dark. Compared with plant chloroplasts, the only cyanobacterial enzyme which differed in its control was the protonmotive ATPase, F,-F,. The y subunit of the cyanobacterial enzyme has already been shown [4,5] to lack a thioredoxin sequence present in higher plants and the presumed lack of lightldark control was confirmed by direct assays [2,3]. In our previous w o k [2,31, cells were grown in continuous light. Nosroc is almost unique amongst the cyanobacteria in that it can grow heterotrophically in complete darkness. We took advantage of this to investigate if enzyme regulation by thioredoxin is flexible and can vary with the mode of growth of the organism. Adaptations of cyanobacterial metabolism were studied in Nosroc sp. Mac cells grown under (a) continuous white light, (b) 14hrs/lOhrs light/dark cycle and (c) complete darkness. Cells were grown in BG11 medium supplemented with 5mM glucose, harvested, and treated with lysozyme [6] to render them osmotically fragile as previously described [2] Dark-adapted lysozyme-treated cells were diluted into an isotonic activation medium (0.33M sorbitol, 3OmM Tricine-KOH, pH 8.0, 5mM MgCI,, 750 U catalaselml), and incubated in the dark or light for 5 min. Aliquots were then taken and enzyme activities measured in a hypotonic medium that caused rapid lysis of the cells. F,-F, and fructose 1,6-bisphosphatase (FBPase) were assayed by the release of phosphate from their respective substrates in a medium containing 5mM MgCI,, 30 mM Tricine-KOH, pH 8.0 and either 2mM ATP or 1mM FBP. G6PDH activity was measured by following NADPH absorbance at 340nm after lysis of the activated cells in a hypotonic medium (5mM MgCI,, 50mM HEPES-KOH pH 7.0) Both dark and light/dark grown cells displayed generally lowered photosynthetic activities compared to light-grown cells. However, the photosynthetic induction period was markedly shorter in the light/dark-grown cells (results not shown). Fig. l(a) shows that F,-F, follows these general trends whereas FBPase activity was actually highest in dark-grown cells. Significantly, FBPase was lightactivated in vivo by the cyanobacterial thioredoxin system in all conditions. By lowering the pH of the assy medium, we were able to detect G6PDH, Fig l(c), which was light-deactivated to some degree in all growth conditions. However, ATPase activity which could not be light-activated regardless of the growth regime. Fig.2 compares the pigment content of cells grown in the differing regimes. Chlorophyll content remains relatively static whilst large changes in phycobiliprotein composition occur that are reminiscent of those seen during complementary chromatic adaptation. Growth in darkness lowers phycoerythrin content and enhances the phycocyanin content. This is under the control of a FIG. 1 Enzymo rctiritios FIG. 2 Pigmontr

Phosphorus uptake by immobilized cells of the alkali‐tolerant cyanobacteriumoscillatoria amphibiaag. ex gomont

Abstract The phosphorus removal potential of the bloom‐forming, alkali‐tolerant cyanobacterium Oscillatoria amphibia was studied by entrapping and immobilizing it in calcium alginate. The uptake kinetics for orthophosphate‐phosphorus (PO4‐P) were determined by growing O. amphibia in Jaworski medium (pH 9) in 14.6 Wm‐2 light intensity at 24±1°C. The pH of the culture medium increased to 11.0 during growth. This facilitated the maintenance of unialgal cultures in the absence of any contaminants. Immobilized filaments showed potential capability of phosphorus accumulation. A stocking biomass of 0.4 μg chl a bead‐1 at external pH 9 was found to be suitable for rapid phosphorus removal. Phosphorus uptake kinetics of immobilized filaments were also dependent on the initial phosphorus concentration. These findings may be useful for designing a bioreactor to optimize phosphorus removal using an immobilized cyanobacterial system.

Regulation of Photosystem Composition in Cyanobacterial Photosynthetic System: Evidence Indicating that Photosystem I Formation is Controlled in Response to the Electron Transport State

Regulation of Photosystem Composition in Cyanobacterial Photosynthetic System: Evidence Indicating that Photosystem I Formation is Controlled in Response to the Electron Transport State

Chromatic Regulation of Photosystem Composition in the Cyanobacterial Photosynthetic System: Kinetic Relationship between Change of Photosystem Composition and Cell Proliferation

Chromatic Regulation of Photosystem Composition in the Cyanobacterial Photosynthetic System: Kinetic Relationship between Change of Photosystem Composition and Cell Proliferation

Regulation of Photosystem Composition in the Cyanobacterial Photosynthetic System: the Regulation Occurs in Response to the Redox State of the Electron Pool Located between the Two Photosystems

Regulation of Photosystem Composition in the Cyanobacterial Photosynthetic System: the Regulation Occurs in Response to the Redox State of the Electron Pool Located between the Two Photosystems

A cyanobacterial system for consolidation of phosphate slimes

Abstract Dilute aqueous suspensions of finely divided mineral waste from phosphate ore beneficiation were allowed to consolidate in the presence of either Anacystis nidulans or Anabaena cylindrica. Addition to this mineral suspension of 2.2 mg (dry weight) of fresh A. nidulans per milliliter of suspension resulted in solids consolidation that exceeded the untreated control by 65% after 11 days. When fresh A. cylindrica was mixed with the slimes suspension, no enhancement of consolidation occurred. Addition of either 1 mgof dry A. nidulans or 1 mg of dry A. cylindrica per milliliter of suspension resulted in consolidation that exceeded the untreated control by 25% after 9 days. Direct addition of A. nidulans to the process water of facilities relying on gravitational dewatering of such mineral suspensions could reduce the residence time in the initial settling ponds. Whether such a process would affect long‐term settling is unknown.