Geitlerinema Sp Research Articles

Requirement for Toll-like Receptor 4 (TLR4) in LPS-induced lung inflammation caused by atypical Cyanobacteria Lipopolysaccharide

Abstract Cyanobacterial blooms found in freshwater sources cause multiple human diseases, including lung inflammation. Cyanobacteria produce atypical lipopolysaccharides (LPS) that can act as either weak TLR4 agonists or even antagonists in in vitro and in vivo models. However, our laboratory demonstrated that LPS from the cyanobacteria Geitlerinema sp. activates immune cells, despite containing altered LPS sugar side chains and inducing modified TLR4 signaling. Additionally, Geitlerinema sp. LPS induced lung inflammation in vivo based on significant neutrophil infiltration 24 hours post LPS exposure. In the current study, we extend our initial findings and asked whether the atypical LPS from an additional cyanobacterial strain, Brasilonema sp., also induces lung inflammation and if TLR4 is required. Our data demonstrate that in vitro, Brasilonema sp. LPS stimulates both Interleukin (IL)-6 and IL-8 production by immortalized airway epithelial cells that is TLR4-dependent, since the addition of the SPA-4 peptide blocks LPS-mediated production of these cytokines. More importantly, Brasilonema sp. LPS induced lung inflammation in wildtype mice but did not induce lung inflammation in TLR4-deficient mice, suggesting that the atypical LPS from cyanobacteria binds to TLR4 to induce lung inflammation. These findings help us to understand the impact of cyanobacteria LPS in neutrophil-dependent airway inflammation in individuals living near freshwater sources contaminated with cyanobacteria.

Application of Spectroscopic Methods for the Identification of Superoxide Dismutases in Cyanobacteria.

Superoxide dismutases (SODs) belong to the group of metalloenzymes that remove superoxide anion radicals and they have been identified in three domains of life: Bacteria, Archaea and Eucarya. SODs in Synechocystis sp. PCC 6803, Gloeobacter violaceus CCALA 979, and Geitlerinema sp. ZHR1A were investigated. We hypothesized that iron (FeSOD) and/or manganese (MnSOD) dominate as active forms in these cyanobacteria. Activity staining and three different spectroscopic methods of SOD activity bands excised from the gels were used to identify a suitable metal in the separated samples. FeSODs or enzymes belonging to the Fe-MnSOD superfamily were detected. The spectroscopic analyses showed that only Fe is present in the SOD activity bands. We found FeSOD in Synechocystis sp. PCC 6803 while two forms in G. violaceus and Geitlerinema sp. ZHR1A: FeSOD1 and FeSOD2 were present. However, no active Cu/ZnSODs were identified in G. violaceus and Geitlerinema sp. ZHR1A. We have shown that selected spectroscopic techniques can be complementary to the commonly used method of staining for SOD activity in a gel. Furthermore, the occurrence of active SODs in the cyanobacteria studied is also discussed in the context of SOD evolution in oxyphotrophs.

Cyanobacteria Geitlerinema sp. lipopolysaccharide induces neutrophil-dependent lung inflammation

Abstract Cyanobacterial blooms found in freshwater systems are a source of environmental toxins that impact the immune system. Geitlerinema sp., a strain of cyanobacteria, produces toxins including lipopolysaccharide (LPS) which induces fever and potential respiratory disease. One mechanism of respiratory disease and inflammation is through the inhalation of LPS that is associated with neutrophil infiltration of the lungs. Based on our previous data that Geitlerinema sp. induces pro-inflammatory cytokines, we hypothesized that inhalation of Geitlerinema sp. LPS would induce lung inflammation in vivo. To address this hypothesis, c57Bl/6 mice were intranasally exposed to Geitlerinema sp. LPS before lungs and BAL fluid were assessed for inflammation and inflammatory markers 24 hours later. Our data show that inhalation of Geitlerinema sp. LPS induced lung inflammation by recruiting neutrophils into the airways. The data also demonstrate that Geitlerinema sp. LPS induces proinflammatory cytokines and chemokines: IL-6, IL-8, IFN-g, RANTES and TNF-a in the BAL fluid. Additionally, in vitro data using an airway epithelial cell line show that Geitlerinema sp. LPS induced production of pro-inflammatory cytokines is dependent on the NF-κB pathway. These data help to better understand the mechanism of Geitlerinema sp. LPS airway-induced inflammation and implicates the importance of the toxin in promoting human disease near freshwater ecosystems where cyanobacteria bloom.

Lipopolysaccharide from the Cyanobacterium Geitlerinema sp. Induces Neutrophil Infiltration and Lung Inflammation.

Glucocorticoid-resistant asthma, which predominates with neutrophils instead of eosinophils, is an increasing health concern. One potential source for the induction of neutrophil-predominant asthma is aerosolized lipopolysaccharide (LPS). Cyanobacteria have recently caused significant tidal blooms, and aerosolized cyanobacterial LPS has been detected near the cyanobacterial overgrowth. We hypothesized that cyanobacterial LPS contributes to lung inflammation by increasing factors that promote lung inflammation and neutrophil recruitment. To test this hypothesis, c57Bl/6 mice were exposed intranasally to LPS from the cyanobacterium member, Geitlerinema sp., in vivo to assess neutrophil infiltration and the production of pro-inflammatory cytokines and chemokines from the bronchoalveolar fluid by ELISA. Additionally, we exposed the airway epithelial cell line, A549, to Geitlerinema sp. LPS in vitro to confirm that airway epithelial cells were stimulated by this LPS to increase cytokine production and the expression of the adhesion molecule, ICAM-1. Our data demonstrate that Geitlerinema sp. LPS induces lung neutrophil infiltration, the production of pro-inflammatory cytokines such as Interleukin (IL)-6, Tumor necrosis factor-alpha, and Interferongamma as well as the chemokines IL-8 and RANTES. Additionally, we demonstrate that Geitlerinema sp. LPS directly activates airway epithelial cells to produce pro-inflammatory cytokines and the adhesion molecule, Intercellular Adhesion Molecule-1 (ICAM-1), in vitro using the airway epithelial cell line, A549. Based on our findings that use Geitlerinema sp. LPS as a model system, the data indicate that cyanobacteria LPS may contribute to the development of glucocorticoid-resistant asthma seen near water sources that contain high levels of cyanobacteria.

Bioactivity of Dodecanoic Acid Extracted from Geitlerinema sp. TRV57

Bioactivity of Dodecanoic Acid Extracted from Geitlerinema sp. TRV57

Eukaryotic and Prokaryotic Phytochelatin Synthases Differ Less in Functional Terms Than Previously Thought: A Comparative Analysis of Marchantia polymorpha and Geitlerinema sp. PCC 7407.

This paper reports functional studies on the enzyme phytochelatin synthase in the liverwort Marchantia polymorpha and the cyanobacterium Geitlerinema sp. strain PCC 7407. In vitro activity assays in control samples (cadmium-untreated) showed that phytochelatin synthase was constitutively expressed in both organisms. In the presence of 100 µM cadmium, in both the liverwort and the cyanobacterium, the enzyme was promptly activated in vitro, and produced phytochelatins up to the oligomer PC4. Likewise, in vivo exposure to 10–36 µM cadmium for 6-120 h induced in both organisms phytochelatin synthesis up to PC4. Furthermore, the glutathione (GSH) levels in M. polymorpha were constitutively low (compared with the average content in higher plants), but increased considerably under cadmium stress. Conversely, the GSH levels in Geitlerinema sp. PCC 7407 were constitutively high, but were halved under metal treatments. At odds with former papers, our results demonstrate that, as in M. polymorpha and other plants, the cyanobacterial phytochelatin synthase exposed to cadmium possesses manifest transpeptidasic activity, being able to synthesize phytochelatins with a degree of oligomerization higher than PC2. Therefore, prokaryotic and eukaryotic phytochelatin synthases differ less in functional terms than previously thought.

Characterization of Phycocyanin Pigment from Marine Filamentous Cyanobacteria Geitlerinema sp.

Algae is a simple and vast group of photosynthetic organisms. Algae grow in most of the natural environments, including water, rocks, and soil, but interestingly also grow on and in other organisms. Their main habitats are freshwater, brackish and marine ecosystems, Also volcanic waters and salt waters. Among them, marine algae are recognized as a rich source of beneficial bioactive compounds. Marine algal originated compounds have been reported to exhibit various biological activities such as anticoagulant, anti-viral, antioxidant, anti-allergic, anti-cancer, anti-inflammatory, anti-obesity, etc. Phycocyanin is a blue-colored naturally existing phycobiliprotein pigment, which is abundant in cyanobacteria, blue-green algae. In this study, phycocyanin was extracted from the Geitlerinema sp. UV-Vis spectroscopic analysis and HPLC analysis confirmed the presence of phycocyanin. The extracted pigment was assessed for their antioxidant property by various methods such as Phosphomolybdenum assay, Ferric ions reducing power assay, DPPH radical scavenging activity, Hydrogen peroxide free radical scavenging assay, Anti-lipid peroxidation activity. The study reveals that the phycocyanin pigments possess the antioxidant property, and it can be used as a promising pharmaceutical and nutraceutical compound.

Physiological plasticity of high-temperature intertidal cyanobacterial microbial mats to temperature and salinity: daily and seasonal in situ photosynthetic performance

ABSTRACTThe physiological plasticity of five cyanobacteria microbial mats from an extreme high temperature intertidal environment (SW Iceland) was analysed both daily and seasonally. Daily cycles under in situ natural conditions were monitored from June to October using pulse-amplitude modulated (PAM) fluorometry and pigment composition in order to study the photosynthetic performance of these microbial mats in relation to environmental fluctuations linked to irradiance and temperature. In vitro temperature and salinity experiments of photosynthetic responses were also conducted. A total of 10 taxa were identified, the most abundant species being Cyanobacterium sp. and Geitlerinema sp. The microbial mats showed a remarkable photosynthetic adaptation to daily and seasonal changes in temperature and solar radiation. For all microbial mats, rETRmax values decreased from June to October, while Fv/Fm remained constant in terms of absolute values. Although high irradiances during June and July affected photosynthesis through photoinhibition, recovery was observed under high temperatures (between 40–50°C), which supports the hypothesis that temperature is a determining factor in the photosynthetic performance of these cyanobacterial mats. Our results showed a significant increase in the Chla-b and phycobiliproteins content from June to October, as well as a significant decrease in total carotenoids content.

Cyanobacteria Respond to Low Levels of Ethylene.

Ethylene is a gas that has long been known to act as a plant hormone. We recently showed that a cyanobacterium, Synechocystis sp. PCC 6803 (Synechocystis) contains an ethylene receptor (SynEtr1) that regulates cell surface and extracellular components leading to altered phototaxis and biofilm formation. To determine whether other cyanobacteria respond to ethylene, we examined the effects of exogenous ethylene on phototaxis of the filamentous cyanobacterium, Geitlerinema sp. PCC 7105 (Geitlerinema). A search of the Geitlerinema genome suggests that two genes encode proteins that contain an ethylene binding domain and Geitlerinema cells have previously been shown to bind ethylene. We call these genes GeiEtr1 and GeiEtr2 and show that in air both are expressed. Treatment with ethylene decreases the abundance of GeiEtr1 transcripts. Treatment of Geitlerinema with 1000 nL L–1 ethylene affected the phototaxis response to white light as well as monochromatic red light, but not blue or green light. This is in contrast to Synechocystis where we previously found ethylene affected phototaxis to all three colors. We also demonstrate that application of ethylene down to 8 nL L–1 stimulates phototaxis of both cyanobacteria as well as biofilm formation of Synechocystis. We formerly demonstrated that the transcript levels of slr1214 and CsiR1 in Synechocystis are reduced by treatment with 1000 nL L–1 ethylene. Here we show that application of ethylene down to 1 nL L–1 causes a reduction in CsiR1 abundance. This is below the threshold for most ethylene responses documented in plants. By contrast, slr1214 is unaffected by this low level of ethylene and only shows a reduction in transcript abundance at the highest ethylene level used. Thus, cyanobacteria are very sensitive to ethylene. However, the dose-binding characteristics of ethylene binding to Geitlerinema and Synechocystis cells as well as to the ethylene binding domain of SynEtr1 heterologously expressed in yeast, are similar to what has been reported for plants and exogenously expressed ethylene receptors from plants. These data are consistent with a model where signal amplification is occurring at the level of the receptors.

Biochemical and Functional Analysis of Cyanobacterium Geitlerinema sp. LPS on Human Monocytes.

Cyanobacterial blooms are an increasing source of environmental toxins that affect both human and animals. After ingestion of cyanobacteria, such as Geitlerinema sp., toxins and lipopolysaccharide (LPS) from this organism induce fever, gastrointestinal illness, and even death. However, little is known regarding the effects of cyanobacterial LPS on human monocytes after exposure to LPS upon ingestion. Based on our previous data using Geitlerinema sp. LPS (which was previously named Oscillatoria sp., a genus belonging to the same order as Geitlerinema), we hypothesized that Geitlerinema sp. LPS would activate human monocytes to proliferate, phagocytose particles, and produce cytokines that are critical for promoting proinflammatory responses in the gut. Our data demonstrate that Geitlerinema sp. LPS induced monocyte proliferation and TNF-α, IL-1, and IL-6 production at high concentrations. In contrast, Geitlerinema sp. LPS is equally capable of inducing monocyte-mediated phagocytosis of FITC-latex beads when compared with Escherichia coli LPS, which was used as a positive control for our experiments. In order to understand the mechanism responsible for the difference in efficacy between Geitlerinema sp. LPS and E. coli LPS, we performed biochemical analysis and identified that Geitlerinema sp. LPS was composed of significantly different sugars and fatty acid side chains in comparison to E. coli LPS. The lipid A portion of Geitlerinema sp. LPS contained longer fatty acid side chains, such as C15:0, C16:0, and C18:0, instead of C12:0 found in E. coli LPS which may explain the decreased efficacy and toxicity of Geitlerinema sp. LPS in comparison to E. coli LPS.

Antioxidant activity of phycocyanin pigment extracted from marine filamentous cyanobacteria Geitlerinema sp TRV57

Abstract Phycocyanin is a blue colored naturally existing phycobiliprotein pigment, which is abundant in cyanobacteria, a blue green algae. In this study, phycocyanin was extracted from the Geitlerinema sp. TRV57. The extracted pigment was assessed for their antioxidant property by various methods such as Phosphomolybdenum assay, Ferric ions reducing power assay, DPPH radical scavenging activity, Hydrogen peroxide free radical scavenging assay, Anti-lipid peroxidation activity. These assays revealed appreciable antioxidant activity of phycocyanin. At a concentration of 200 µg/mL, the phycocyanin exhibited a maximum absorbance of 0.49 by phosphomolybdenum assay, 0.85 absorbance by ferric ion reducing assay, 78.75% of DPPH scavenging activity, 95.27% of H2O2 scavenging activity. The IC50 value of phycocyanin was found to be 185 µg/mL for Anti-lipid peroxidation assay. The study reveals that the phycocyanin pigments possess antioxidant property and it can be used as a promising pharmaceutical and nutraceutical compound.

Screening cyanobacteria from marine coastal waters of Thailand for biohydrogen production

Cyanobacteria are prokaryotic organisms capable of oxygenic photosynthesis. H2 can be produced by cyanobacterial bidirectional hydrogenase, but mainly during anaerobic dark fermentation. Here, we screened H2 producing cyanobacteria isolated from marine environments in Thailand and optimized physiological conditions for maximizing H2 production of the selected isolate. Most of the 54 cyanobacterial strains isolated and purified from samples of seawater, stones, sand, and shells in the Gulf of Thailand and the Andaman Sea, southern part of Thailand produced H2 when cells were incubated in nitrogen-deprived medium under dark/anaerobic condition. The filamentous non-heterocystous cyanobacterium Geitlerinema sp. RMK-SH10 gave the highest H2 yield with highest H2 production rate found in 7-day grown cells. Geitlerinema sp. RMK-SH10 showed maximum H2 production rate of 0.271 ± 0.013 μmol H2 mg−1 dry weight h−1 when incubated in NaNO3-free ASN III medium containing 0.2 M NaCl, 18.9 mmol C-atom of glucose L−1, and 0.1 μM Ni2+. These results suggest that the marine filamentous cyanobacterium Geitlerinema sp. RMK-SH10 has high potential as a H2 producer amenable for further improvement by genetic manipulation.

Structural characterization and antioxidant potential of phycocyanin from the cyanobacterium Geitlerinema sp. H8DM

We are reporting characterization of phycocyanin (PC), a prime light harvesting pigment, composed of nearly the same molecular weight of alpha- (17.5 kDa) and beta- (18.1 kDa) subunits in Geitlerinema sp. H8DM. Phycocyanin was purified using ammonium sulfate and anionic exchange chromatography. The fluorescence emission spectrum of PC was 637 nm when excited over 589 nm, which denoted integrity and functionality of protein structure. PC was depicted as a single subunit of ~18 kDa based on SDS-PAGE. However, similarity between both subunits was proven by two spots on gel using two dimensional gel electrophoresis. MALDI ToF/ToF showed structure similarities with alpha and beta subunits of PC. Urea induced Gibbs free energy denoted that folding and structural stability of this pigment is similar to phycocyanin of other species. Biophysical properties of peptide sequence were analyzed for several parameters and 3D model for its correlation as antioxidant. Furthermore, verification of in-silico data of PC was done by in vitro anti-oxidant assays. Hence, due to high availability, stability and antioxidant properties it can be used for auxiliary applications as colorant and therapeutic agent against oxidative stress.

Whole genome sequence analysis of Geitlerinema sp. FC II unveils competitive edge of the strain in marine cultivation system for biofuel production

A filamentous cyanobacteria, Geitlerinema sp. FC II, was isolated from marine algae culture pond at Reliance Industries Limited (RIL), India. The 6.7 Mb draft genome of FC II encodes for 6697 protein coding genes. Analysis of the whole genome sequence revealed presence of nif gene cluster, supporting its capability to fix atmospheric nitrogen. FC II genome contains two variants of sulfide:quinone oxidoreductases (SQR), which is a crucial elector donor in cyanobacterial metabolic processes. FC II is characterized by the presence of multiple CRISPR- Cas (Clustered Regularly Interspaced Short Palindrome Repeats – CRISPR associated proteins) clusters, multiple variants of genes encoding photosystem reaction centres, biosynthetic gene clusters of alkane, polyketides and non-ribosomal peptides. Presence of these pathways will help FC II in gaining an ecological advantage over other strains for biomass production in large scale cultivation system. Hence, FC II may be used for production of biofuel and other industrially important metabolites.

CRISPR-Cas Defense System and Potential Prophages in Cyanobacteria Associated with the Coral Black Band Disease.

Understanding how pathogens maintain their virulence is critical to developing tools to mitigate disease in animal populations. We sequenced and assembled the first draft genome of Roseofilum reptotaenium AO1, the dominant cyanobacterium underlying pathogenicity of the virulent coral black band disease (BBD), and analyzed parts of the BBD-associated Geitlerinema sp. BBD_1991 genome in silico. Both cyanobacteria are equipped with an adaptive, heritable clustered regularly interspaced short palindromic repeats (CRISPR)-Cas defense system type I-D and have potential virulence genes located within several prophage regions. The defense system helps to prevent infection by viruses and mobile genetic elements via identification of short fingerprints of the intruding DNA, which are stored as templates in the bacterial genome, in so-called “CRISPRs.” Analysis of CRISPR target sequences (protospacers) revealed an unusually high number of self-targeting spacers in R. reptotaenium AO1 and extraordinary long CRIPSR arrays of up to 260 spacers in Geitlerinema sp. BBD_1991. The self-targeting spacers are unlikely to be a form of autoimmunity; instead these target an incomplete lysogenic bacteriophage. Lysogenic virus induction experiments with mitomycin C and UV light did not reveal an actively replicating virus population in R. reptotaenium AO1 cultures, suggesting that phage functionality is compromised or excision could be blocked by the CRISPR-Cas system. Potential prophages were identified in three regions of R. reptotaenium AO1 and five regions of Geitlerinema sp. BBD_1991, containing putative BBD relevant virulence genes, such as an NAD-dependent epimerase/dehydratase (a homolog in terms of functionality to the third and fourth most expressed gene in BBD), lysozyme/metalloendopeptidases and other lipopolysaccharide modification genes. To date, viruses have not been considered to be a component of the BBD consortium or a contributor to the virulence of R. reptotaenium AO1 and Geitlerinema sp. BBD_1991. We suggest that the presence of virulence genes in potential prophage regions, and the CRISPR-Cas defense systems are evidence of an arms race between the respective cyanobacteria and their bacteriophage predators. The presence of such a defense system likely reduces the number of successful bacteriophage infections and mortality in the cyanobacteria, facilitating the progress of BBD.

Photosynthetic Versatility in the Genome of Geitlerinema sp. PCC 9228 (Formerly Oscillatoria limnetica 'Solar Lake'), a Model Anoxygenic Photosynthetic Cyanobacterium.

Anoxygenic cyanobacteria that use sulfide as the electron donor for photosynthesis are a potentially influential but poorly constrained force on Earth’s biogeochemistry. Their versatile metabolism may have boosted primary production and nitrogen cycling in euxinic coastal margins in the Proterozoic. In addition, they represent a biological mechanism for limiting the accumulation of atmospheric oxygen, especially before the Great Oxidation Event and in the low-oxygen conditions of the Proterozoic. In this study, we describe the draft genome sequence of Geitlerinema sp. PCC 9228, formerly Oscillatoria limnetica ‘Solar Lake’, a mat-forming diazotrophic cyanobacterium that can switch between oxygenic photosynthesis and sulfide-based anoxygenic photosynthesis (AP). Geitlerinema possesses three variants of psbA, which encodes protein D1, a core component of the photosystem II reaction center. Phylogenetic analyses indicate that one variant is closely affiliated with cyanobacterial psbA genes that code for a D1 protein used for oxygen-sensitive processes. Another version is phylogenetically similar to cyanobacterial psbA genes that encode D1 proteins used under microaerobic conditions, and the third variant may be cued to high light and/or elevated oxygen concentrations. Geitlerinema has the canonical gene for sulfide quinone reductase (SQR) used in cyanobacterial AP and a putative transcriptional regulatory gene in the same operon. Another operon with a second, distinct sqr and regulatory gene is present, and is phylogenetically related to sqr genes used for high sulfide concentrations. The genome has a comprehensive nif gene suite for nitrogen fixation, supporting previous observations of nitrogenase activity. Geitlerinema possesses a bidirectional hydrogenase rather than the uptake hydrogenase typically used by cyanobacteria in diazotrophy. Overall, the genome sequence of Geitlerinema sp. PCC 9228 highlights potential cyanobacterial strategies to cope with fluctuating redox gradients and nitrogen availability that occur in benthic mats over a diel cycle. Such dynamic geochemical conditions likely also challenged Proterozoic cyanobacteria, modulating oxygen production. The genetic repertoire that underpins flexible oxygenic/anoxygenic photosynthesis in cyanobacteria provides a foundation to explore the regulation, evolutionary context, and biogeochemical implications of these co-occurring metabolisms in Earth history.

Unraveling the Physiological Roles of the Cyanobacterium Geitlerinema sp. BBD and Other Black Band Disease Community Members through Genomic Analysis of a Mixed Culture.

Black band disease (BBD) is a cyanobacterial-dominated polymicrobial mat that propagates on and migrates across coral surfaces, necrotizing coral tissue. Culture-based laboratory studies have investigated cyanobacteria and heterotrophic bacteria isolated from BBD, but the metabolic potential of various BBD microbial community members and interactions between them remain poorly understood. Here we report genomic insights into the physiological and metabolic potential of the BBD-associated cyanobacterium Geitlerinema sp. BBD 1991 and six associated bacteria that were also present in the non-axenic culture. The essentially complete genome of Geitlerinema sp. BBD 1991 contains a sulfide quinone oxidoreductase gene for oxidation of sulfide, suggesting a mechanism for tolerating the sulfidic conditions of BBD mats. Although the operon for biosynthesis of the cyanotoxin microcystin was surprisingly absent, potential relics were identified. Genomic evidence for mixed-acid fermentation indicates a strategy for energy metabolism under the anaerobic conditions present in BBD during darkness. Fermentation products may supply carbon to BBD heterotrophic bacteria. Among the six associated bacteria in the culture, two are closely related to organisms found in culture-independent studies of diseased corals. Their metabolic pathways for carbon and sulfur cycling, energy metabolism, and mechanisms for resisting coral defenses suggest adaptations to the coral surface environment and biogeochemical roles within the BBD mat. Polysulfide reductases were identified in a Flammeovirgaceae genome (Bacteroidetes) and the sox pathway for sulfur oxidation was found in the genome of a Rhodospirillales bacterium (Alphaproteobacteria), revealing mechanisms for sulfur cycling, which influences virulence of BBD. Each genomic bin possessed a pathway for conserving energy from glycerol degradation, reflecting adaptations to the glycerol-rich coral environment. The presence of genes for detoxification of reactive oxygen species and resistance to antibiotics suggest mechanisms for combating coral defense strategies. This study builds upon previous research on BBD and provides new insights into BBD disease etiology.

Fresh Water Cyanobacteria Geitlerinema sp. CCC728 and Arthrospira sp. CCC729 as an Anticancer Drug Resource.

An increasing number of cancer patients worldwide, especially in third world countries, have raised concern to explore natural drug resources, such as the less explored fresh water filamentous cyanobacteria. Six strains of cyanobacteria (Phormidium sp. CCC727, Geitlerinema sp. CCC728, Arthrospira sp. CCC729, Phormidium sp. CCC731, Phormidium sp. CCC730, and Leptolyngbya sp. CCC732) were isolated (paddy fields and ponds in the Banaras Hindu University, campus) and five strains screened for anticancer potential using human colon adenocarcinoma (HT29) and human kidney adenocarcinoma (A498) cancer cell lines. Geitlerinema sp. CCC728 and Arthrospira sp. CCC729 were the most potent as determined by examination of morphological features and by inhibition of growth by graded concentrations of crude extracts and thin-layer chromatography (TLC) eluates. Cell cycle analysis and multiplex assays using cancer biomarkers also confirmed Geitlerinema sp. CCC728 and Arthrospira sp. CCC729 as cancer drug resources. Apoptotic studies in the cells of A498 (cancer) and MCF-10A (normal human epithelial) exposed to crude extracts and TLC fractions revealed no significant impact on MCF-10A cells emphasizing its importance in the development of anticancer drug. Identification of biomolecules from these extracts are in progress.

Effect of copper and lead on two consortia of phototrophic microorganisms and their capacity to sequester metals

The roles of consortia of phototrophic microorganisms have been investigated in this paper to determine their potential role to tolerate or resist metals and to capture them from polluted cultures. With this purpose, two consortia of microorganisms: on one hand, Geitlerinema sp. DE2011 (Ge) and Scenedesmus sp. DE2009 (Sc) (both identified in this paper by molecular biology methods) isolated from Ebro Delta microbial mats, and on the other, Spirulina sp. PCC 6313 (Sp) and Chroococcus sp. PCC 9106 (Ch), from Pasteur culture collection were polluted with copper and lead. In order to analyze the ability of these consortia to tolerate and capture metals, copper and lead were selected, because both have been detected in Ebro Delta microbial mats.The tolerance-resistance to copper and lead for both consortia was determined in vivo and at cellular level by Confocal Laser Scanning Microscopy (CLSM-λscan function). The results obtained demonstrate that both consortia are highly tolerant-resistant to lead and that the limits between the copper concentration having cytotoxic effect and that having an essential effect are very close in these microorganisms.The capacity of both consortia to capture extra- and intracellular copper and lead was determined by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) respectively, coupled to an Energy Dispersive X-ray detector (EDX). The results showed that all the microorganisms assayed were able to capture copper extracellularly in the extrapolymeric substances, and lead extra- and intracellularly in polyphosphate inclusions. Moreover, the studied micro-organisms did not exert any inhibitory effect on each other's metal binding capacity.From the results obtained in this paper, it can be concluded that consortia of phototrophic microorganisms could play a very important role in biorepairing sediments polluted by metals, as a result of their ability to tolerate or resist high concentrations of metals and to bioaccumulate them, extra- and intracellulary.

Detection of Bioactive Exometabolites Produced by the Filamentous Marine Cyanobacterium Geitlerinema sp.

Marine cyanobacteria are noted for their ability to excrete metabolites with biotic properties. This paper focuses on such exometabolites obtained from the culture of the marine filamentous cyanobacterium Geitlerinema sp. strain, their purification and subsequent analyses. By this means the recoveries of the active compounds, a prerequisite for properly determining their concentration, are quantified here for the first time. We demonstrate a new procedure using Amberlite XAD-1180 resin in combination with the eluent isopropanol for extraction of the culture media and gas chromatography as simplified chemical analysis. This procedure reduced necessary bacteria cultivation time (from 150 to 21 days) at low volumes of culture media (300 mL) required for identification of two selected bioactive compounds: 4,4′-dihydroxybiphenyl and harmane.