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Sample records for cyanobacterial toxins

  1. Cyanobacterial toxins: risk management for health protection

    SciTech Connect

    Codd, Geoffrey A.; Morrison, Louise F.; Metcalf, James S

    2005-03-15

    This paper reviews the occurrence and properties of cyanobacterial toxins, with reference to the recognition and management of the human health risks which they may present. Mass populations of toxin-producing cyanobacteria in natural and controlled waterbodies include blooms and scums of planktonic species, and mats and biofilms of benthic species. Toxic cyanobacterial populations have been reported in freshwaters in over 45 countries, and in numerous brackish, coastal, and marine environments. The principal toxigenic genera are listed. Known sources of the families of cyanobacterial toxins (hepato-, neuro-, and cytotoxins, irritants, and gastrointestinal toxins) are briefly discussed. Key procedures in the risk management of cyanobacterial toxins and cells are reviewed, including derivations (where sufficient data are available) of tolerable daily intakes (TDIs) and guideline values (GVs) with reference to the toxins in drinking water, and guideline levels for toxigenic cyanobacteria in bathing waters. Uncertainties and some gaps in knowledge are also discussed, including the importance of exposure media (animal and plant foods), in addition to potable and recreational waters. Finally, we present an outline of steps to develop and implement risk management strategies for cyanobacterial cells and toxins in waterbodies, with recent applications and the integration of Hazard Assessment Critical Control Point (HACCP) principles.

  2. Formation and Control of Cyanobacterial Toxins

    EPA Science Inventory

    This presentation will cover the formation of harmful algal blooms and the control of their toxins. Data will be presented from current ORD projects on the treatment of cyanobacterial toxins through drinking water treatment facilities. The results will demonstrate that current c...

  3. Toxins produced in cyanobacterial water blooms – toxicity and risks

    PubMed Central

    Bláha, Luděk; Babica, Pavel; Maršálek, Blahoslav

    2009-01-01

    Cyanobacterial blooms in freshwaters represent a major ecological and human health problem worldwide. This paper briefly summarizes information on major cyanobacterial toxins (hepatotoxins, neurotoxins etc.) with special attention to microcystins-cyclic heptapeptides with high acute and chronic toxicities. Besides discussion of human health risks, microcystin ecotoxicology and consequent ecological risks are also highlighted. Although significant research attention has been paid to microcystins, cyanobacteria produce a wide range of currently unknown toxins, which will require research attention. Further research should also address possible additive, synergistic or antagonistic effects among different classes of cyanobacterial metabolites, as well as interactions with other toxic stressors such as metals or persistent organic pollutants. PMID:21217843

  4. Health Risk Assessment for Cyanobacterial Toxins in Seafood

    PubMed Central

    Mulvenna, Vanora; Dale, Katie; Priestly, Brian; Mueller, Utz; Humpage, Andrew; Shaw, Glen; Allinson, Graeme; Falconer, Ian

    2012-01-01

    Cyanobacteria (blue-green algae) are abundant in fresh, brackish and marine waters worldwide. When toxins produced by cyanobacteria are present in the aquatic environment, seafood harvested from these waters may present a health hazard to consumers. Toxicity hazards from seafood have been internationally recognised when the source is from marine algae (dinoflagellates and diatoms), but to date few risk assessments for cyanobacterial toxins in seafood have been presented. This paper estimates risk from seafood contaminated by cyanobacterial toxins, and provides guidelines for safe human consumption. PMID:22690165

  5. Toxicological Review of Cyanobacterial Toxins: Cylindrospermopsin (External Review Draft)

    EPA Science Inventory

    The National Center for Environmental Assessment has prepared the Toxicological Reviews of Cyanobacterial Toxins: Anatoxin-a, Cylindrospermopsin and Microcystins (LR, RR, YR and LA) as a series of dose-response assessments to support the health assessment of unregulated contamina...

  6. Cyanobacterial (blue-green algal) toxins in water supplies: Cylindrospermopsins.

    PubMed

    Falconer, Ian R; Humpage, Andrew R

    2006-08-01

    The toxic alkaloid cylindrospermopsin is produced by a range of cyanobacterial species worldwide. It was first identified in the species Cylindrospermopsis raciborskii from tropical waters, and has since been isolated from four other genera in locations ranging from Israel to Japan. High concentrations of the organisms and toxin have been identified in reservoirs, natural lakes, and rivers in summer in the USA and in Australia. The toxin is a particular problem in drinking water sources as concentrations in the free water are appreciable, so that removal of the filaments during water treatment does not remove the toxin. The toxicity resulting from oral ingestion is seen in the liver, kidneys, stomach, intestine, and white blood cells, with some vascular damage in mice. Gastrointestinal as well as liver injury has been observed in human poisoning. Studies of toxicity in vitro have shown inhibition of protein synthesis. Genotoxicity has also been demonstrated, and there is preliminary evidence for carcinogenicity. A Guideline Value for safe water supply of 1 microg/L has been proposed. Research into toxin measurement techniques and water treatment methods has indicated that effective control measures may be practicable for this toxin in drinking water. Considerably more research is needed to fully define the health risks from this toxin.

  7. Emerging high throughput analyses of cyanobacterial toxins and toxic cyanobacteria.

    PubMed

    Sivonen, Kaarina

    2008-01-01

    The common occurrence of toxic cyanobacteria causes problems for health of animals and human beings. More research and good monitoring systems are needed to protect water users. It is important to have rapid, reliable and accurate analysis i.e. high throughput methods to identify the toxins as well as toxin producers in the environment. Excellent methods, such as ELISA already exist to analyse cyanobacterial hepatotoxins and saxitoxins, and PPIA for microcystins and nodularins. The LC/MS method can be fast in identifying the toxicants in the samples. Further development of this area should resolve the problems with sampling and sample preparation, which still are the bottlenecks of rapid analyses. In addition, the availability of reliable reference materials and standards should be resolved. Molecular detection methods are now routine in clinical and criminal laboratories and may also become important in environmental diagnostics. One prerequisite for the development of molecular analysis is that pure cultures of the producer organisms are available for identification of the biosynthetic genes responsible for toxin production and for proper testing of the diagnostic methods. Good methods are already available for the microcystin and nodularin-producing cyanobacteria such as conventional PCR, quantitative real-time PCR and microarrays/DNA chips. The DNA-chip technology offers an attractive monitoring system for toxic and non-toxic cyanobacteria. Only with these new technologies (PCR + DNA-chips) will we be able to study toxic cyanobacteria populations in situ and the effects of environmental factors on the occurrence and proliferation of especially toxic cyanobacteria. This is likely to yield important information for mitigation purposes. Further development of these methods should include all cyanobacterial biodiversity, including all toxin producers and primers/probes to detect producers of neurotoxins, cylindrospermopsins etc. (genes are unknown). The on

  8. Toxicity and recovery in the pregnant mouse after gestational exposure to the cyanobacterial toxin, cylindrospermopsin.

    EPA Science Inventory

    Cylindrospermopsin (CYN) is a tricyclic alkaloid toxin produced by fresh water cyanobacterial species worldwide. CYN has been responsible for both livestock and human poisoning after oral exposure. This study investigated the toxicity of CYN to pregnant mice exposed during differ...

  9. DETOXIFICATION OF CYANOBACTERIAL TOXIN - CONTAMINATED WATER USING TIO2 PHOTOCATALYTIC FILMS

    EPA Science Inventory

    Cyanobacterial harmfal algal blooms (CyanoHABs) often produce undesirable color, odor and taste and more importantly, potent toxins that can cause chronic, acute and acute letha poisonings to wild and domestic animals and humans

  10. Kinetics of reactions between chlorine and the cyanobacterial toxins microcystins.

    PubMed

    Acero, Juan L; Rodriguez, Eva; Meriluoto, Jussi

    2005-04-01

    Blooms of cyanobacteria can give rise to the production of toxins which contaminate drinking water sources. Among the oxidants and disinfectants typically applied in waterworks, chlorine has been found to be effective for the degradation of microcystins. In the present study, unknown second-order rate constants for the reactions of microcystin-LR (MC-LR), -RR and -YR with chlorine were determined over a wide pH range. It was found that an increase of pH has a negative effect on the microcystin degradation rate. Apparent second-order rate constant for the chlorination of MC-LR at 20 degrees C varied from 475 M(-1)s(-1) at pH 4.8 to 9.8 M(-1)s(-1) at pH 8.8. From these apparent second-order rate constants, rate constants for the reactions of MC-LR with hypochlorous acid (HOCl) and hypochlorite (ClO-) were evaluated. Half-life times ranged from minutes at pH 6 to 1 h at pH 8 for a constant residual chlorine concentration of 1.0-0.5 mgl(-1), typical of oxidation pre-treatment and final disinfection. Similar reactivity with chlorine was found for MC-RR and MC-YR. Therefore, chlorination is a feasible option for microcystin degradation during oxidation and disinfection processes, and can be applied in drinking water treatment in case of cyanobacterial toxin risk if the pH is kept below 8.

  11. The integration of nutrients, cyanobacterial biomass and toxins: from a multi-use reservoir through water treatment

    EPA Science Inventory

    This presentation is an integrated evaluation of cyanobacterial growth and toxin production, from a reservoir through drinking water treatment - where biomass and toxin removal are achieved. Data is generated by a variety of methods: online instrumentation for chlorophyll, diss...

  12. Variable Cyanobacterial Toxin and Metabolite Profiles across Six Eutrophic Lakes of Differing Physiochemical Characteristics

    PubMed Central

    Beversdorf, Lucas J.; Weirich, Chelsea A.; Bartlett, Sarah L.; Miller, Todd. R.

    2017-01-01

    Future sustainability of freshwater resources is seriously threatened due to the presence of harmful cyanobacterial blooms, and yet, the number, extent, and distribution of most cyanobacterial toxins—including “emerging” toxins and other bioactive compounds—are poorly understood. We measured 15 cyanobacterial compounds—including four microcystins (MC), saxitoxin (SXT), cylindrospermopsin (CYL), anatoxin-a (ATX) and homo-anatoxin-a (hATX), two anabaenopeptins (Apt), three cyanopeptolins (Cpt), microginin (Mgn), and nodularin (NOD)—in six freshwater lakes that regularly experience noxious cHABs. MC, a human liver toxin, was present in all six lakes and was detected in 80% of all samples. Similarly, Apt, Cpt, and Mgn were detected in all lakes in roughly 86%, 50%, and 35% of all samples, respectively. Despite being a notable brackish water toxin, NOD was detected in the two shallowest lakes—Wingra (4.3 m) and Koshkonong (2.1 m). All compounds were highly variable temporally, and spatially. Metabolite profiles were significantly different between lakes suggesting lake characteristics influenced the cyanobacterial community and/or metabolite production. Understanding how cyanobacterial toxins are distributed across eutrophic lakes may shed light onto the ecological function of these metabolites, provide valuable information for their remediation and removal, and aid in the protection of public health. PMID:28208628

  13. Monitoring of shrimp and farmed fish sold in Canada for cyanobacterial toxins.

    PubMed

    Niedzwiadek, Barbara; Scott, Peter M; Lau, Ben P-Y

    2012-01-01

    Sixty-one samples of shrimp and 32 samples of farmed fish collected from retail markets across Canada were analyzed for cyanobacterial toxins, including microcystins, paralytic shellfish poisons (saxitoxins), cylindrospermopsin, and β-N-methylamino-L-alanine, using established methods of analysis. None of these toxins were detected in any of the samples. Some shrimp samples screened for paralytic shellfish poisons showed the presence of unknown peaks in the chromatogram after periodate oxidation.

  14. Impacts of Early-Stage Drinking Water Treatment on Cyanobacterial Toxin Release and Degradation

    EPA Science Inventory

    This presentation summarizes the impact of potassium permanganate application to suspensions of intact, toxin-producing cyanobacterial cells at pH 7 and 9, oxidant doses of 1, 2.5 and 5 mg/L, turbidities of 0.1, 5 and 20 NTU, and powdered activated carbon doses of 0 and 10 mg/L

  15. Effect of ozonation on the removal of cyanobacterial toxins during drinking water treatment.

    PubMed Central

    Hoeger, Stefan J; Dietrich, Daniel R; Hitzfeld, Bettina C

    2002-01-01

    Water treatment plants faced with toxic cyanobacteria have to be able to remove cyanotoxins from raw water. In this study we investigated the efficacy of ozonation coupled with various filtration steps under different cyanobacterial bloom conditions. Cyanobacteria were ozonated in a laboratory-scale batch reactor modeled on a system used by a modern waterworks, with subsequent activated carbon and sand filtration steps. The presence of cyanobacterial toxins (microcystins) was determined using the protein phosphatase inhibition assay. We found that ozone concentrations of at least 1.5 mg/L were required to provide enough oxidation potential to destroy the toxin present in 5 X 10(5 )Microcystis aeruginosa cells/mL [total organic carbon (TOC), 1.56 mg/L]. High raw water TOC was shown to reduce the efficiency of free toxin oxidation and destruction. In addition, ozonation of raw waters containing high cyanobacteria cell densities will result in cell lysis and liberation of intracellular toxins. Thus, we emphasize that only regular and simultaneous monitoring of TOC/dissolved organic carbon and cyanobacterial cell densities, in conjunction with online residual O(3) concentration determination and efficient filtration steps, can ensure the provision of safe drinking water from surface waters contaminated with toxic cyanobacterial blooms. PMID:12417484

  16. THE CYANOBACTERIAL TOXIN, CYLINDROSPERMOPSIN, INDUCES FETAL TOXICITY IN THE MOUSE AFTER EXPOSURE LATE IN GESTATION

    EPA Science Inventory

    Cylindrospermopsin (cyn) is a cyanobacterial toxin implicated in human and wildlife poisonings. We have completed studies investigating the potential of purified cyn to induce developmental toxicity in mammals. The teratology study involved intraperitoneal injections (8.0¿128ug/k...

  17. Effect of ozonation on the removal of cyanobacterial toxins during drinking water treatment.

    PubMed

    Hoeger, Stefan J; Dietrich, Daniel R; Hitzfeld, Bettina C

    2002-11-01

    Water treatment plants faced with toxic cyanobacteria have to be able to remove cyanotoxins from raw water. In this study we investigated the efficacy of ozonation coupled with various filtration steps under different cyanobacterial bloom conditions. Cyanobacteria were ozonated in a laboratory-scale batch reactor modeled on a system used by a modern waterworks, with subsequent activated carbon and sand filtration steps. The presence of cyanobacterial toxins (microcystins) was determined using the protein phosphatase inhibition assay. We found that ozone concentrations of at least 1.5 mg/L were required to provide enough oxidation potential to destroy the toxin present in 5 X 10(5 )Microcystis aeruginosa cells/mL [total organic carbon (TOC), 1.56 mg/L]. High raw water TOC was shown to reduce the efficiency of free toxin oxidation and destruction. In addition, ozonation of raw waters containing high cyanobacteria cell densities will result in cell lysis and liberation of intracellular toxins. Thus, we emphasize that only regular and simultaneous monitoring of TOC/dissolved organic carbon and cyanobacterial cell densities, in conjunction with online residual O(3) concentration determination and efficient filtration steps, can ensure the provision of safe drinking water from surface waters contaminated with toxic cyanobacterial blooms.

  18. Toxicological Review of Cyanobacterial Toxins: Microcystins Lr, Rr, Yr and La (External Review Draft)

    EPA Science Inventory

    The National Center for Environmental Assessment has prepared the Toxicological Reviews of Cyanobacterial Toxins: Anatoxin-a, Cylindrospermopsin and Microcystins (LR, RR, YR and LA) as a series of dose-response assessments to support the health assessment of unregulated contamina...

  19. Toxicological Review of Cyanobacterial Toxins: Anatoxin-a (External Review Draft)

    EPA Science Inventory

    The National Center for Environmental Assessment has prepared the Toxicological Reviews of Cyanobacterial Toxins: Anatoxin-a, Cylindrospermopsin and Microcystins (LR, RR, YR and LA) as a series of dose-response assessments to support the health assessment of unregulated contamina...

  20. CYANOBACTERIAL TOXINS AND 2005 ISOCHAB EXPOSURE ASSESSMENT WORKGROUP

    EPA Science Inventory

    The US EPA, Office of Research and Development, in collaboration with other US federal agencies, is leading the organization of an International Symposium on Cyanobacterial Harmful Algal Blooms on 6-10 September, 2005. The goal of this symposium is to develop a comprehensive nat...

  1. Dynamics of cyanobacteria and cyanobacterial toxins and their correlation with environmental parameters in Tri An Reservoir, Vietnam.

    PubMed

    Dao, Thanh-Son; Nimptsch, Jorge; Wiegand, Claudia

    2016-08-01

    This study evaluates the water quality from Tri An Reservoir, a drinking water supply for several million people in southern Vietnam, in terms of cyanobacterial biomass and their potent toxins, microcystins (MCs). Cyanobacteria, their toxins and environmental parameters were monitored monthly for 1 year (April 2008-March 2009) at six stations covering a transect through the reservoir. Dynamics of cyanobacterial abundance in relation to cyanobacterial biomass, toxins and environmental factors were investigated. Environmental variables from Tri An Reservoir favored algal and cyanobacterial development. However, cyanobacterial biomass and proportion varied widely, influenced by physical conditions, available nutrients and nutrient competition among the phytoplankton groups. Cyanobacterial biomass correlated slightly positively to temperature, pH and biochemical oxygen demand (BOD5), but negatively to total inorganic nitrogen concentrations. During most of the sampling times, MC concentrations in the reservoir were quite low (≤0.07 μg L(-1) MC-LR equivalent), and presented a slight positive correlation to BOD5, total nitrogen:total phosphorus ratio and cyanobacterial biomass. However, in cyanobacterial scum samples, which now and then occurred in the reservoir, MC concentrations reached up to 640 μg g(-1) DW(-1). The occurrence of MC in the reservoir poses a risk to local residents who use the water daily for domestic purposes.

  2. Cyanobacterial toxins: removal during drinking water treatment, and human risk assessment.

    PubMed

    Hitzfeld, B C; Höger, S J; Dietrich, D R

    2000-03-01

    Cyanobacteria (blue-green algae) produce toxins that may present a hazard for drinking water safety. These toxins (microcystins, nodularins, saxitoxins, anatoxin-a, anatoxin-a(s), cylindrospermopsin) are structurally diverse and their effects range from liver damage, including liver cancer, to neurotoxicity. The occurrence of cyanobacteria and their toxins in water bodies used for the production of drinking water poses a technical challenge for water utility managers. With respect to their removal in water treatment procedures, of the more than 60 microcystin congeners, microcystin-LR (L, L-leucine; R, L-arginine) is the best studied cyanobacterial toxin, whereas information for the other toxins is largely lacking. In response to the growing concern about nonlethal acute and chronic effects of microcystins, the World Health Organization has recently set a new provisional guideline value for microcystin-LR of 1.0 microg/L drinking water. This will lead to further efforts by water suppliers to develop effective treatment procedures to remove these toxins. Of the water treatment procedures discussed in this review, chlorination, possibly micro-/ultrafiltration, but especially ozonation are the most effective in destroying cyanobacteria and in removing microcystins. However, these treatments may not be sufficient during bloom situations or when a high organic load is present, and toxin levels should therefore be monitored during the water treatment process. In order to perform an adequate human risk assessment of microcystin exposure via drinking water, the issue of water treatment byproducts will have to be addressed in the future.

  3. Determining important parameters related to cyanobacterial alkaloid toxin exposure

    SciTech Connect

    Love, A H

    2005-09-16

    Science-based decision making required robust and high-fidelity mechanistic data about the system dynamics and impacts of system changes. Alkaloid cyanotoxins have the characteristics to warrant consideration for their potential threat. Since insufficient information is available to construct a systems model for the alkaloid cyanotoxins, saxitoxins, anatoxins, and anatoxin-a(S), an accurate assessments of these toxins as a potential threat for use for intentional contamination is not possible. Alkaloid cyanotoxin research that contributed to such a model has numerous areas of overlap for natural and intentional health effects issues that generates dual improvements to the state of the science. The use of sensitivity analyses of systems models can identify parameters that, when determined, result in the greatest impact to the overall system and may help to direct the most efficient use of research funding. This type of modeling-assisted experimentation may allow rapid progress for overall system understanding compared to observational or disciplinary research agendas. Assessment and management of risk from intentional contamination can be performed with greater confidence when mechanisms are known and the relationships between different components are validated. This level of understanding allows high-fidelity assessments that do not hamper legitimate possession of these toxins for research purposes, while preventing intentional contamination that would affect public health. It also allows for appropriate response to an intentional contamination event, even if the specific contamination had not been previous considered. Development of science-based decision making tools will only improve our ability to address the new requirements addressing potential threats to our nation.

  4. Degradation Mechanism of Cyanobacterial Toxin Cylindrospermopsin by Hydroxyl Radicals in Homogeneous UV/H2O2 Process

    EPA Science Inventory

    The degradation of cylindrospermopsin (CYN), a widely distributed and highly toxic cyanobacterial toxin (cyanotoxin), remains poorly elucidated. In this study, the mechanism of CYN destruction by UV-254 nm/H2O2 advanced oxidation process (AOP) was investigated by mass spectrometr...

  5. Trophic transfer of cyanobacterial toxins from zooplankton to planktivores: consequences for pike larvae and mysid shrimps.

    PubMed

    Karjalainen, Miina; Reinikainen, Marko; Spoof, Lisa; Meriluoto, Jussi A O; Sivonen, Kaarina; Viitasalo, Markku

    2005-06-01

    The aim of this study was to evaluate the potentially harmful effects of zooplankton preexposed to cyanobacteria on two planktivorous animals: a fish larva (pike, Esox lucius) and a mysid shrimp (Neomysis integer). The planktivores were fed zooplankton from a natural community that had been preexposed to cell-free extract or to purified toxin (nodularin) of the cyanobacterium Nodularia spumigena, and the growth, feeding, and pellet production of the planktivores, as well as the toxin content of the pellets, were measured. In addition, radiolabeled nodularin ((3)H-dihydronodularin) was used in separate experiments to measure the vector transfer of nodularin from zooplankton to their predators. During 11-day exposures, dissolved nodularin was transferred to pike larvae and N. integer via zooplankton at very low rates of accumulation. Treatment with N. spumigena extract decreased the ingestion and feces production rates of pike larvae. With purified nodularin alone, no such effect could be observed. No effect on molting cycle length, fecal pellet production, C:N ratio, or growth of N. integer was detected. The results suggest that dissolved cyanobacterial toxins released during bloom decay can have a negative impact on feeding and, hence, on the growth of fish larvae via zooplankton, even without direct contact between cyanobacteria and the fish.

  6. Effect of chlorine dioxide on cyanobacterial cell integrity, toxin degradation and disinfection by-product formation.

    PubMed

    Zhou, Shiqing; Shao, Yisheng; Gao, Naiyun; Li, Lei; Deng, Jing; Zhu, Mingqiu; Zhu, Shumin

    2014-06-01

    Bench scale tests were conducted to study the effect of chlorine dioxide (ClO2) oxidation on cell integrity, toxin degradation and disinfection by-product formation of Microcystis aeruginosa. The simulated cyanobacterial suspension was prepared at a concentration of 1.0×10(6)cells/mL and the cell integrity was measured with flow cytometry. Results indicated that ClO2 can inhibit the photosynthetic capacity of M. aeruginosa cells and almost no integral cells were left after oxidation at a ClO2 dose of 1.0mg/L. The total toxin was degraded more rapidly with the ClO2 dosage increasing from 0.1mg/L to 1.0mg/L. Moreover, the damage on cell structure after oxidation resulted in released intracellular organic matter, which contributed to the formation of trihalomethanes (THMs) and haloacetic acids (HAAs) as disinfection by-products. Therefore, the use of ClO2 as an oxidant for treating algal-rich water should be carefully considered.

  7. Guidelines for Design and Sampling for Cyanobacterial Toxin and Taste-and-Odor Studies in Lakes and Reservoirs

    USGS Publications Warehouse

    Graham, Jennifer L.; Loftin, Keith A.; Ziegler, Andrew C.; Meyer, Michael T.

    2008-01-01

    Cyanobacteria and associated toxins and taste-and-odor compounds are of increasing environmental concern. However, consistent guidelines for the development of studies assessing cyanobacterial toxins and taste-and-odor compounds presently are not available. This report provides guidance for the development of scientific studies of cyanobacteria and associated by-products in lakes and reservoirs. Topics include: background information on cyanobacteria, toxins, and taste-and-odor compounds; spatial and temporal considerations that are unique to the cyanobacteria in lakes and reservoirs; common study types, objectives, and approaches for studies of cyanobacteria and associated toxins and taste-and-odor compounds; general guidelines for collecting samples; and information on sample handling, preparation, processing, and shipping.

  8. Microcystins (cyanobacterial toxins) in surface waters of rural Bangladesh: pilot study.

    PubMed

    Welker, Martin; Khan, Saleha; Haque, Md Mahfuzul; Islam, Sirajul; Khan, Nurul Huda; Chorus, Ingrid; Fastner, Jutta

    2005-12-01

    In Bangladesh the exposure of millions of inhabitants to water from (shallow) tube wells contaminated with high geogenic loads of arsenic is a major concern. As an alternative to the costly drilling of deep wells, the return to the use of surface water as a source of drinking water is considered. In addition to the well-known hazards of water borne infectious diseases associated with the use of surface water, recently the potential public health implications of toxic cyanobacteria have been recognized. As a first step towards a risk assessment for cyanotoxins in Bangladesh surface waters, seston samples of 79 ponds were analysed in late summer 2002 for the presence of cyanobacteria and microcystins (MCYST), the most frequently detected cyanobacterial toxins worldwide. Microcystins could be detected in 39 ponds, mostly together with varying abundance of potentially microcystin-producing genera such as Microcystis, Planktothrix and Anabaena. Total microcystin concentrations ranged between <0.1 and > 1,000 microg l(-1), and more than half of the positive samples contained high concentrations of more than 10 microg l(-1). The results clearly show that concentrations of microcystins well above the provisional WHO guideline value of 1 microg l(-1) MCYST-LR can be frequently detected in Bangladesh ponds. Thus, an increasing use of surface water for human consumption introduces a risk of replacing one health hazard by another and therefore needs to be accompanied by cyanotoxin hazard assessments.

  9. Degradation mechanism of cyanobacterial toxin cylindrospermopsin by hydroxyl radicals in homogeneous UV/H₂O₂ process.

    PubMed

    He, Xuexiang; Zhang, Geshan; de la Cruz, Armah A; O'Shea, Kevin E; Dionysiou, Dionysios D

    2014-04-15

    The degradation of cylindrospermopsin (CYN), a widely distributed and highly toxic cyanobacterial toxin (cyanotoxin), remains poorly elucidated. In this study, the mechanism of CYN destruction by UV-254 nm/H2O2 advanced oxidation process (AOP) was investigated by mass spectrometry. Various byproducts identified indicated three common reaction pathways: hydroxyl addition (+16 Da), alcoholic oxidation or dehydrogenation (-2 Da), and elimination of sulfate (-80 Da). The initiation of the degradation was observed at the hydroxymethyl uracil and tricyclic guanidine groups; uracil moiety cleavage/fragmentation and further ring-opening of the alkaloid were also noted at an extended reaction time or higher UV fluence. The degradation rates of CYN decreased and less byproducts (species) were detected using natural water matrices; however, CYN was effectively eliminated under extended UV irradiation. This study demonstrates the efficiency of CYN degradation and provides a better understanding of the mechanism of CYN degradation by hydroxyl radical, a reactive oxygen species that can be generated by most AOPs and is present in natural water environment.

  10. Biodegradation of the cyanobacterial toxin microcystin LR in natural water and biologically active slow sand filters.

    PubMed

    Bourne, David G; Blakeley, Robert L; Riddles, Peter; Jones, Gary J

    2006-03-01

    A bacterium (MJ-PV) previously demonstrated to degrade the cyanobacterial toxin microcystin LR, was investigated for bioremediation applications in natural water microcosms and biologically active slow sand filters. Enhanced degradation of microcystin LR was observed with inoculated (1 x 10(6) cell/mL) treatments of river water dosed with microcystin LR (>80% degradation within 2 days) compared to uninoculated controls. Inoculation of MJ-PV at lower concentrations (1 x 10(2)-1 x 10(5) cells/mL) also demonstrated enhanced microcystin LR degradation over control treatments. Polymerase chain reactions (PCR) specifically targeting amplification of 16S rDNA of MJ-PV and the gene responsible for initial degradation of microcystin LR (mlrA) were successfully applied to monitor the presence of the bacterium in experimental trials. No amplified products indicative of an endemic MJ-PV population were observed in uninoculated treatments indicating other bacterial strains were active in degradation of microcystin LR. Pilot scale biologically active slow sand filters demonstrated degradation of microcystin LR irrespective of MJ-PV bacterial inoculation. PCR analysis detected the MJ-PV population at all locations within the sand filters where microcystin degradation was measured. Despite not observing enhanced degradation of microcystin LR in inoculated columns compared to uninoculated column, these studies demonstrate the effectiveness of a low-technology water treatment system like biologically active slow sand filters for removal of microcystins from reticulated water supplies.

  11. Nodularin, a cyanobacterial toxin, is synthesized in planta by symbiotic Nostoc sp.

    PubMed

    Gehringer, Michelle M; Adler, Lewis; Roberts, Alexandra A; Moffitt, Michelle C; Mihali, Troco K; Mills, Toby J T; Fieker, Claus; Neilan, Brett A

    2012-10-01

    The nitrogen-fixing bacterium, Nostoc, is a commonly occurring cyanobacterium often found in symbiotic associations. We investigated the potential of cycad cyanobacterial endosymbionts to synthesize microcystin/nodularin. Endosymbiont DNA was screened for the aminotransferase domain of the toxin biosynthesis gene clusters. Five endosymbionts carrying the gene were screened for bioactivity. Extracts of two isolates inhibited protein phosphatase 2A and were further analyzed using electrospray ionization mass spectrometry (ESI-MS)/MS. Nostoc sp. 'Macrozamia riedlei 65.1' and Nostoc sp. 'Macrozamia serpentina 73.1' both contained nodularin. High performance liquid chromatography (HPLC) HESI-MS/MS analysis confirmed the presence of nodularin at 9.55±2.4 ng μg-1 chlorophyll a in Nostoc sp. 'Macrozamia riedlei 65.1' and 12.5±8.4 ng μg-1 Chl a in Nostoc sp. 'Macrozamia serpentina 73.1' extracts. Further scans indicated the presence of the rare isoform [L-Har(2)] nodularin, which contains L-homoarginine instead of L-arginine. Nodularin was also present at 1.34±0.74 ng ml(-1) (approximately 3 pmol per g plant ww) in the methanol root extracts of M. riedlei MZ65, while the presence of [L-Har(2)] nodularin in the roots of M. serpentina MZ73 was suggested by HPLC HESI-MS/MS analysis. The ndaA-B and ndaF genomic regions were sequenced to confirm the presence of the hybrid polyketide/non-ribosomal gene cluster. A seven amino-acid insertion into the NdaA-C1 domain of N. spumigena NSOR10 protein was observed in all endosymbiont-derived sequences, suggesting the transfer of the nda cluster from N. spumigena to terrestrial Nostoc species. This study demonstrates the synthesis of nodularin and [L-Har(2)] nodularin in a non-Nodularia species and the production of cyanobacterial hepatotoxin by a symbiont in planta.

  12. Physiological and antioxidant responses of Medicago sativa-rhizobia symbiosis to cyanobacterial toxins (Microcystins) exposure.

    PubMed

    El Khalloufi, Fatima; Oufdou, Khalid; Lahrouni, Majida; Faghire, Mustapha; Peix, Alvaro; Ramírez-Bahena, Martha Helena; Vasconcelos, Vitor; Oudra, Brahim

    2013-12-15

    Toxic cyanobacteria in freshwaters can induce potent harmful effects on growth and development of plants irrigated with contaminated water. In this study, the effect of cyanobacteria extract containing Microcystins (MC) on Medicago sativa-rhizobia symbiosis was investigated in order to explore plants response through biomass production, photosynthetic pigment and antioxidant enzymes analysis: Peroxidase (POD), Polyphenoloxidase (PPO) and Catalase (CAT). Alfalfa plants were inoculated with two endosymbiotic rhizobial strains: RhOL1 (MC less sensitive strain) and RhOL3 (MC more sensitive strain), to evaluate the rhizobial contribution on the plant response cultured under cyanobacterial toxins stress. The two rhizobia strains were identified as Ensifer meliloti by sequence analysis of their rrs and atpD genes. The chronic exposure to MC extract showed shoot, root and nodules dry weight decrease, in both symbiosis cultures. The rate of decline in plants inoculated with RhOL3 was higher than that in symbiosis with RhOL1 mainly at 20 μg L(-1) of MC. Cyanotoxins also reduced photosynthetic pigment content and generated an oxidative stress observed at cellular level. POD, PPO and CAT activities were significantly increased in leaves, roots and nodules of alfalfa plants exposed to MC. These enzyme activities were higher in plants inoculated with RhOL3 especially when alfalfa plants were exposed to 20 μg L(-1) of MC. The present paper reports new scientific finding related to the behavior of rhizobia-M. sativa associations to MC (Microcystins) for later recommendation concerning the possible use of these symbiosis face to crops exposure to MC contaminated water irrigation.

  13. Variation in the response of the invasive species Potamopyrgus antipodarum (Smith) to natural (cyanobacterial toxin) and anthropogenic (herbicide atrazine) stressors.

    PubMed

    Gerard, Claudia; Poullain, Virginie

    2005-11-01

    In the context of increasing freshwater pollution, the impact on life-traits (survival, growth and fecundity) and locomotion of Potamopyrgus antipodarum of a 5-week field-concentration exposure to the cyanobacterial toxin microcystin-LR and the triazine herbicide, atrazine was studied. Whatever the age of exposed snails (juveniles, subadults, adults), microcystin-LR induced a decrease in survival, growth and fecundity but had no effect on locomotion. Atrazine induced a decrease in locomotory activity but had no significant effect on the life-traits. These results are discussed in terms of consequences to field populations.

  14. The Geographic Distribution of Liver Cancer in Canada Does Not Associate with Cyanobacterial Toxin Exposure

    PubMed Central

    Labine, Meaghan A.; Green, Chris; Mak, Giselle; Xue, Lin; Nowatzki, Janet; Griffith, Jane; Minuk, Gerald Y.

    2015-01-01

    Background: The incidence of liver cancer has been increasing in Canada over the past decade, as has cyanobacterial contamination of Canadian freshwater lakes and drinking water sources. Cyanotoxins released by cyanobacteria have been implicated in the pathogenesis of liver cancer. Objective: To determine whether a geographic association exists between liver cancer and surrogate markers of cyanobacterial contamination of freshwater lakes in Canada. Methods: A negative binomial regression model was employed based on previously identified risk factors for liver cancer. Results: No association existed between the geographic distribution of liver cancer and surrogate markers of cyanobacterial contamination. As predicted, significant associations existed in areas with a high prevalence of hepatitis B virus infection, large immigrant populations and urban residences. Discussion and Conclusions: The results of this study suggest that cyanobacterial contamination of freshwater lakes does not play an important role in the increasing incidence of liver cancer in Canada. PMID:26633441

  15. The Course of Toxicity in the Pregnant Mouse after Exposure to the Cyanobacterial Toxin, Cylindrospermopsin: Clinical Effects, Serum Chemistries, Hematology and Histopathology

    EPA Science Inventory

    Cylindrospermopsin (CYN) is a toxin produced by a wide variety of fresh water cyanobacterial species worldwide and induces significant adverse effects in both livestock and humans. This study investigated the course of CYN-induced toxicity in pregnant mice exposed during either t...

  16. Toxicological aspects of treatment to remove cyanobacterial toxins from drinking water determined using the heterozygous P53 transgenic mouse model.

    PubMed

    Senogles-Derham, P-J; Seawright, A; Shaw, G; Wickramisingh, W; Shahin, M

    2003-06-01

    The presence of toxic cyanobacteria in drinking water reservoirs renders the need to develop treatment methods for the 'safe' removal of their associated toxins. Chlorine has been shown to successfully remove a range of cyanotoxins including microcystins, cylindrospermopsin and saxitoxins. Each cyanotoxin requires specific treatment parameters, particularly solution pH and free chlorine residual. However, currently there has not been any investigation into the toxicological effect of solutions treated for the removal of these cyanotoxins by chlorine. Using the P53(def) transgenic mouse model male and female C57BL/6J hybrid mice were used to investigate potential cancer inducing effects from such oral dosing solutions. Both purified cyanotoxins and toxic cell-free extract cyanobacterial solutions were chlorinated and administered over 90 and 170 days (respectively) in drinking water. No increase in cancer was found in any treatment. The parent cyanotoxins, microcystins, cylindrospermopsin and saxitoxins were readily removed by chlorine. There was no significant increase in the disinfection by-products trihalomethanes or haloacetic acids, levels found were well below guideline values. Histological examination identified no effect of treatment solutions except male mice treated with chlorinated cylindrospermopsin (as a cell free extract). In this instance 40% of males were found to have fatty vacuolation in their livers, cause unknown. It is recommended that further toxicology be undertaken on chlorinated cyanobacterial solutions, particularly for non-genotoxic carcinogenic compounds, for example the Tg. AC transgenic mouse model.

  17. Cyanobacterial toxins: modes of actions, fate in aquatic and soil ecosystems, phytotoxicity and bioaccumulation in agricultural crops.

    PubMed

    Corbel, Sylvain; Mougin, Christian; Bouaïcha, Noureddine

    2014-02-01

    The occurrence of harmful cyanobacterial blooms in surface waters is often accompanied by the production of a variety of cyanotoxins. These toxins are designed to target in humans and animals specific organs on which they act: hepatotoxins (liver), neurotoxins (nervous system), cytotoxic alkaloids, and dermatotoxins (skin), but they often have important side effects too. When introduced into the soil ecosystem by spray irrigation of crops they may affect the same molecular pathways in plants having identical or similar target organs, tissues, cells or biomolecules. There are also several indications that terrestrial plants, including food crop plants, can bioaccumulate cyanotoxins and present, therefore, potential health hazards for human and animals. The number of publications concerned with phytotoxic effects of cyanotoxins on agricultural plants has increased recently. In this review, we first examine different cyanotoxins and their modes of actions in humans and mammals and occurrence of target biomolecules in vegetable organisms. Then we present environmental concentrations of cyanotoxins in freshwaters and their fate in aquatic and soil ecosystems. Finally, we highlight bioaccumulation of cyanotoxins in plants used for feed and food and its consequences on animals and human health. Overall, our review shows that the information on the effects of cyanotoxins on non-target organisms in the terrestrial environment is particularly scarce, and that there are still serious gaps in the knowledge about the fate in the soil ecosystems and phytotoxicity of these toxins.

  18. Identification of Microcystis aeruginosa Peptides Responsible for Allergic Sensitization and Characterization of Functional Interactions between Cyanobacterial Toxins and Immunogenic Peptides

    PubMed Central

    Geh, Esmond N.; Ghosh, Debajyoti; McKell, Melanie; de la Cruz, Armah A.; Stelma, Gerard

    2015-01-01

    Background The cyanobacterium species Microcystis aeruginosa produces microcystin and an array of diverse metabolites believed responsible for their toxicity and/or immunogenicity. Previously, chronic rhinitis patients were demonstrated to elicit a specific IgE response to nontoxic strains of M. aeruginosa by skin-prick testing, indicating that cyanobacteria allergenicity resides in a non-toxin–producing component of the organism. Objectives We sought to identify and characterize M. aeruginosa peptide(s) responsible for allergic sensitization in susceptible individuals, and we investigated the functional interactions between cyanobacterial toxins and their coexpressed immunogenic peptides. Methods Sera from patients and extracts from M. aeruginosa toxic [MC(+)] and nontoxic [MC(–)] strains were used to test IgE-specific reactivity by direct and indirect ELISAs; 2D gel electrophoresis, followed by immunoblots and mass spectrometry (MS), was performed to identify the relevant sensitizing peptides. Cytotoxicity and mediator release assays were performed using the MC(+) and MC(–) lysates. Results We found specific IgE to be increased more in response to the MC(–) strain than the MC(+) strain. This response was inhibited by preincubation of MC(–) lysate with increasing concentrations of microcystin. MS revealed that phycocyanin and the core-membrane linker peptide are the responsible allergens, and MC(–) extracts containing these proteins induced β-hexosaminidase release in rat basophil leukemia cells. Conclusions Phycobiliprotein complexes in M. aeruginosa have been identified as the relevant sensitizing proteins. Our finding that allergenicity is inhibited in a dose-dependent manner by microcystin toxin suggests that further investigation is warranted to understand the interplay between immunogenicity and toxicity of cyanobacteria under diverse environmental conditions. Citation Geh EN, Ghosh D, McKell M, de la Cruz AA, Stelma G, Bernstein JA. 2015

  19. Cyanobacterial Cells and Toxins:Evaluating Source Water Trends and Propagation through Lake Erie Treatment Facilities

    EPA Science Inventory

    Harmful algal blooms (HABs), and their associated toxins, in fresh water lakes and reservoirs are drawing the attention of utilities and state regulators nation-wide. Recognizing the potential health and economic consequences, the US Environmental Protection Agency, in partnersh...

  20. Monitoring and removal of cyanobacterial toxins from drinking water by algal-activated carbon.

    PubMed

    Ibrahim, Wael M; Salim, Emad H; Azab, Yahia A; Ismail, Abdel-Hamid M

    2016-10-01

    Microcystins (MCs) are the most potent toxins that can be produced by cyanobacteria in drinking water supplies. This study investigated the abundance of toxin-producing algae in 11 drinking water treatment plants (DWTPs). A total of 26 different algal taxa were identified in treated water, from which 12% were blue green, 29% were green, and 59% were diatoms. MC levels maintained strong positive correlations with number of cyanophycean cells in raw and treated water of different DWTPs. Furthermore, the efficiency of various algal-based adsorbent columns used for the removal of these toxins was evaluated. The MCs was adsorbed in the following order: mixed algal-activated carbon (AAC) ≥ individual AAC > mixed algal powder > individual algal powder. The results showed that the AAC had the highest efficient columns capable of removing 100% dissolved MCs from drinking water samples, thereby offering an economically feasible technology for efficient removal and recovery of MCs in DWTPs.

  1. subsection{Fate of the cyanobacterial toxin Microcystin-LR during bank filtration - column experiments and modelling}

    NASA Astrophysics Data System (ADS)

    Gerstenberg, Karen; Nützmann, Gunnar

    2010-05-01

    Over the past several years there has been an increasing interest in microcystins and other cyanobacterial toxins in surface waters and oxic groundwater. Since these compounds are strong hepatotoxic agents their presence in surface water is undesirable and can especially cause health problems if the contaminated surface water is used for drinking water abstraction by bank filtration. During the subsurface sediment passage microcystins are biodegraded by adapted microorganisms in a co-metabolic way together with other compounds - a process which causes depletion of oxygen in the sediment and production of anoxic zones in the underground. Presence or absence of oxygen as electron acceptor for microbial energetic metabolism is a crucial factor for degradation. Up to now most studies focused on the fate of microcystin under oxic conditions. But if during bank filtration anoxic zones occur, these approaches cannot be used for description and prediction of transport and degradation processes of microcystin in bank filtration sites. For a better understanding of anoxic degradation of microcystins during subsurface sediment passage laboratory column experiments were designed to simulate the transport and degradation conditions in the aquifer. In small columns of about 20 cm length different cyanobacterial concentrations and potential electron acceptors are adjusted. The outflowing water was analyzed with respect to Microcystin-LR and the main ion concentrations. Transport and sorption parameters were investigated by flow experiments, and quantification of the main parameters was done by inverse modelling using a MATLAB inverse transport model. Flow and sorption experiments reconfirmed that Microcystin-LR does not tend to sorb to the sandy material. Considering the anoxic degradation behaviour of the toxin the redox state of the system was assumed to be the most important factor and therefore varied during the experiments by adding supplemental nitrate or nitrite. The

  2. Inactivation Kinetics of the Cyanobacterial Toxin Microcystin-LR by Free Chlorine

    EPA Science Inventory

    Worldwide, the increasing occurrence of toxins produced by cyanobacteria in water bodies used as source waters for drinking water has become an important public health issue. Microcystin-LR is one of the most commonly found cyanotoxins. A detailed evaluation of the free chlorine ...

  3. Detection of the cyanobacterial toxin, microcystin-LR, using a novel recombinant antibody-based optical-planar waveguide platform.

    PubMed

    Murphy, Caroline; Stack, Edwina; Krivelo, Svetlana; McPartlin, Daniel A; Byrne, Barry; Greef, Charles; Lochhead, Michael J; Husar, Greg; Devlin, Shauna; Elliott, Christopher T; O'Kennedy, Richard J

    2015-05-15

    Microcystins are a major group of cyanobacterial heptapeptide toxins found in freshwater and brackish environments. There is currently an urgent requirement for highly-sensitive, rapid and in-expensive detection methodologies for these toxins. A novel single chain fragment variable (scFv) fragment was generated and is the first known report of a recombinant anti-microcystin avian antibody. In a surface plasmon resonance-based immunoassay, the antibody fragment displayed cross-reactivity with seven microcystin congeners (microcystin-leucine-arginine (MC-LR) 100%, microcystin-tyrosine-arginine (MC-YR) 79.7%, microcystin-leucine-alanine (MC-LA) 74.8%, microcystin-leucine-phenylalanine (MC-LF) 67.5%, microcystin-leucine-tryptophan (MC-LW) 63.7%, microcystin-arginine-arginine (MC-RR) 60.1% and nodularin (Nod) 69.3%, % cross reactivity). Following directed molecular evolution of the parental clone the resultant affinity-enhanced antibody fragment was applied in an optimized fluorescence immunoassay on a planar waveguide detection system. This novel immuno-sensing format can detect free microcystin-LR with a functional limit of detection of 0.19 ng mL(-1)and a detection range of 0.21-5.9 ng mL(-1). The assay is highly reproducible (displaying percentage coefficients of variance below 8% for intra-day assays and below 11% for inter-day assays), utilizes an inexpensive cartridge system with low reagent volumes and can be completed in less than twenty minutes.

  4. Immunoassays and Biosensors for the Detection of Cyanobacterial Toxins in Water

    PubMed Central

    Weller, Michael G.

    2013-01-01

    Algal blooms are a frequent phenomenon in nearly all kinds of fresh water. Global warming and eutrophication by waste water, air pollution and fertilizers seem to lead to an increased frequency of occurrence. Many cyanobacteria produce hazardous and quite persistent toxins, which can contaminate the respective water bodies. This may limit the use of the raw water for many purposes. The purification of the contaminated water might be quite costly, which makes a continuous and large scale treatment economically unfeasible in many cases. Due to the obvious risks of algal toxins, an online or mobile detection method would be highly desirable. Several biosensor systems have been presented in the literature for this purpose. In this review, their mode of operation, performance and general suitability for the intended purpose will be described and critically discussed. Finally, an outlook on current developments and future prospects will be given. PMID:24196435

  5. Neonatal exposure to the cyanobacterial toxin BMAA induces changes in protein expression and neurodegeneration in adult hippocampus.

    PubMed

    Karlsson, Oskar; Berg, Anna-Lena; Lindström, Anna-Karin; Hanrieder, Jörg; Arnerup, Gunnel; Roman, Erika; Bergquist, Jonas; Lindquist, Nils Gunnar; Brittebo, Eva B; Andersson, Malin

    2012-12-01

    The cyanobacterial toxin β-N-methylamino-L-alanine (BMAA) has been proposed to contribute to neurodegenerative disease. We have previously reported a selective uptake of BMAA in the mouse neonatal hippocampus and that exposure during the neonatal period causes learning and memory impairments in adult rats. The aim of this study was to characterize effects in the brain of 6-month-old rats treated neonatally (postnatal days 9-10) with the glutamatergic BMAA. Protein changes were examined using the novel technique Matrix-Assisted Laser Desorption Ionization (MALDI) imaging mass spectrometry (IMS) for direct imaging of proteins in brain cryosections, and histological changes were examined using immunohistochemistry and histopathology. The results showed long-term changes including a decreased expression of proteins involved in energy metabolism and intracellular signaling in the adult hippocampus at a dose (150 mg/kg) that gave no histopathological lesions in this brain region. Developmental exposure to a higher dose (460 mg/kg) also induced changes in the expression of S100β, histones, calcium- and calmodulin-binding proteins, and guanine nucleotide-binding proteins. At this dose, severe lesions in the adult hippocampus including neuronal degeneration, cell loss, calcium deposits, and astrogliosis were evident. The data demonstrate subtle, sometimes dose-dependent, but permanent effects of a lower neonatal dose of BMAA in the adult hippocampus suggesting that BMAA could potentially disturb many processes during the development. The detection of BMAA in seafood stresses the importance of evaluating the magnitude of human exposure to this neurotoxin.

  6. Occupational and environmental hazard assessments for the isolation, purification and toxicity testing of cyanobacterial toxins

    PubMed Central

    2009-01-01

    Cyanobacteria can produce groups of structurally and functionally unrelated but highly potent toxins. Cyanotoxins are used in multiple research endeavours, either for direct investigation of their toxicologic properties, or as functional analogues for various biochemical and physiological processes. This paper presents occupational safety guidelines and recommendations for personnel working in field, laboratory or industrial settings to produce and use purified cyanotoxins and toxic cyanobacteria, from bulk harvesting of bloom material, mass culture of laboratory isolates, through routine extraction, isolation and purification. Oral, inhalational, dermal and parenteral routes are all potential occupational exposure pathways during the various stages of cyanotoxin production and application. Investigation of toxicologic or pharmacologic properties using in vivo models may present specific risks if radiolabelled cyanotoxins are employed, and the potential for occupational exposure via the dermal route is heightened with the use of organic solvents as vehicles. Inter- and intra-national transport of living cyanobacteria for research purposes risks establishing feral microalgal populations, so disinfection of culture equipment and destruction of cells by autoclaving, incineration and/or chlorination is recommended in order to prevent viable cyanobacteria from escaping research or production facilities. PMID:19925679

  7. Hydroxyl radical oxidation of cylindrospermopsin (cyanobacterial toxin) and its role in the photochemical transformation.

    PubMed

    Song, Weihua; Yan, Shuwen; Cooper, William J; Dionysiou, Dionysios D; O'Shea, Kevin E

    2012-11-20

    Cylindrospermopsin (CYN), an alkaloid guanidinium sulfated toxin, is produced by a number of cyanobacteria regularly found in lakes, rivers, and reservoirs. Steady-state and time-resolved radiolysis methods were used to determine reaction pathways and kinetic parameters for the reactions of hydroxyl radical with CYN. The absolute bimolecular reaction rate constant for the reaction of hydroxyl radical with CYN is (5.08 ± 0.16) × 10(9) M(-1) s(-1). Comparison of the overall reaction rate of CYN with hydroxyl radical with the individual reaction rate for addition to the uracil ring in CYN indicate the majority of the hydroxyl radicals (84%) react at the uracil functionality of CYN. Product analyses using liquid chromatography-mass spectrometry indicate the major products from the reaction of hydroxyl radical with CYN involve attack of hydroxyl radical at the uracil ring and hydrogen abstraction from the hydroxy-methine bridge linking the uracil ring to the tricyclic guanidine functionality. The role of hydroxyl radical initiated pathways in the natural organic matter (NOM) photosensitized transformation of CYN were evaluated. Scavenger and trapping experiments indicate that hydroxyl radical mediated transformations account for approximately ~70% of CYN destruction in surface waters under solar irradiation in the presence of NOM. The absence of solvent isotope effect indicates singlet oxygen does not play a significant role in the NOM sensitized transformation of CYN. The primary degradation pathways for HO• mediated and NOM photosensitized destruction of CYN involve destruction of the uracil ring. The fundamental kinetic parameters determined from these studies are critical for the accurate evaluation of hydroxyl-radical based technologies for the remediation of this problematic cyanotoxin in drinking water and important in the assessment of the environmental oxidative transformation of uracil based compounds.

  8. Supported liquid membrane-liquid chromatography-mass spectrometry analysis of cyanobacterial toxins in fresh water systems

    NASA Astrophysics Data System (ADS)

    Mbukwa, Elbert A.; Msagati, Titus A. M.; Mamba, Bhekie B.

    Harmful algal blooms (HABs) are increasingly becoming of great concern to water resources worldwide due to indiscriminate waste disposal habits resulting in water pollution and eutrophication. When cyanobacterial cells lyse (burst) they release toxins called microcystins (MCs) that are well known for their hepatotoxicity (causing liver damage) and have been found in eutrophic lakes, rivers, wastewater ponds and other water reservoirs. Prolonged exposure to low concentrated MCs are equally of health importance as they are known to be bioaccumulative and even at such low concentration do exhibit toxic effects to aquatic animals, wildlife and human liver cells. The application of common treatment processes for drinking water sourced from HABs infested reservoirs have the potential to cause algal cell lyses releasing low to higher amounts of MCs in finished water. Trace microcystins in water/tissue can be analyzed and quantified using Liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) following solid-phase extraction (SPE) sample clean-up procedures. However, extracting MCs from algal samples which are rich in chlorophyll pigments and other organic matrices the SPE method suffers a number of drawbacks, including cartridge clogging, long procedural steps and use of larger volumes of extraction solvents. We applied a supported liquid membrane (SLM) based technique as an alternative sample clean-up method for LC-ESI-MS analysis of MCs from both water and algal cells. Four (4) MC variants (MC-RR, -YR, -LR and -WR) from lyophilized cells of Microcystis aeruginosa and water collected from a wastewater pond were identified) and quantified using LC-ESI-MS following a SLM extraction and liquid partitioning step, however, MC-WR was not detected from water extracts. Within 45 min of SLM extraction all studied MCs were extracted and pre-concentrated in approximately 15 μL of an acceptor phase at an optimal pH 2.02 of the donor phase (sample). The highest

  9. Crystal structures of protein phosphatase-1 bound to motuporin and dihydromicrocystin-LA: elucidation of the mechanism of enzyme inhibition by cyanobacterial toxins.

    PubMed

    Maynes, Jason T; Luu, Hue A; Cherney, Maia M; Andersen, Raymond J; Williams, David; Holmes, Charles F B; James, Michael N G

    2006-02-10

    The microcystins and nodularins are tumour promoting hepatotoxins that are responsible for global adverse human health effects and wildlife fatalities in countries where drinking water supplies contain cyanobacteria. The toxins function by inhibiting broad specificity Ser/Thr protein phosphatases in the host cells, thereby disrupting signal transduction pathways. A previous crystal structure of a microcystin bound to the catalytic subunit of protein phosphatase-1 (PP-1c) showed distinct changes in the active site region when compared with protein phosphatase-1 structures bound to other toxins. We have elucidated the crystal structures of the cyanotoxins, motuporin (nodularin-V) and dihydromicrocystin-LA bound to human protein phosphatase-1c (gamma isoform). The atomic structures of these complexes reveal the structural basis for inhibition of protein phosphatases by these toxins. Comparisons of the structures of the cyanobacterial toxin:phosphatase complexes explain the biochemical mechanism by which microcystins but not nodularins permanently modify their protein phosphatase targets by covalent addition to an active site cysteine residue.

  10. SURFACTANT TEMPLATED SOL-GEL SYNTHESIS OF MESOPOROUS TIO2 PHOTOCATALYSTS AND THEIR APPLICATION IN THE DESTRUCTION OF CYANOBACTERIAL TOXINS

    EPA Science Inventory

    In the symposium, we will present the synthesis and properties of the mesoporous TIO2 films and membranes and fundamental and systematic study on the decomposition pathway of such biological toxins.

  11. Mesoporous nitrogen-doped TiO2 for the photocatalytic destruction of the cyanobacterial toxin microcystin-LR under visible light irradiation.

    PubMed

    Choi, Hyeok; Antoniou, Maria G; Pelaez, Miguel; De la Cruz, Armah A; Shoemaker, Jody A; Dionysiou, Dionysios D

    2007-11-01

    The presence of the harmful cyanobacterial toxins in water resources worldwide drives the development of an innovative and practical water treatment technology with great urgency. This study deals with two important aspects: the fabrication of mesoporous nitrogen-doped TiO2 (N-TiO2) photocatalysts and their environmental application for the destruction of microcystin-LR (MC-LR) under visible light. In a nanotechnological sol-gel synthesis method, a nitrogen-containing surfactant (dodecylammonium chloride) was introduced as a pore templating material for tailor-designing the structural properties of TiO2 and as a nitrogen dopant for its visible light response. The resulting N-TiO2 exhibited significantly enhanced structural properties including 2-8 nm mesoporous structure (porosity 44%) and high surface area of 150 m2/g. Red shift in light absorbance up to 468 nm, 0.9 eV lower binding energy of electrons in Ti 2p state, and reduced interplanar distance of crystal lattices proved nitrogen doping in the TiO2 lattice. Due to its narrow band gap at 2.65 eV, N-TiO2 efficiently degraded MC-LR under visible spectrum above 420 nm. Acidic condition (pH 3.5) was more favorable for the adsorption and photocatalytic degradation of MC-LR on N-TiO2 due to electrostatic attraction forces between negatively charged MC-LR and +6.5 mV charged N-TiO2. Even under UV light, MC-LR was decomposed 3-4 times faster using N-TiO2 than control TiO2. The degradation pathways and reaction intermediates of MC-LR were not directly related to the energy source for TiO2 activation (UV and visible) and nature of TiO2 (neat and nitrogen-doped). This study implies a strong possibility for the in situ photocatalytic remediation of contaminated water with cyanobacterial toxins and other toxic compounds using solar light, a sustainable source of energy.

  12. The course of toxicity in the pregnant mouse after exposure to the cyanobacterial toxin cylindrospermopsin: clinical effects, serum chemistries, hematology, and histopathology.

    PubMed

    Chernoff, N; Rogers, E H; Zehr, R D; Gage, M I; Travlos, G S; Malarkey, D E; Brix, A; Schmid, J E; Hill, D

    2014-01-01

    Cylindrospermopsin (CYN) is a toxin produced by a variety of fresh-water cyanobacterial species worldwide and induces significant adverse effects in both livestock and humans. This study investigated the course of CYN-induced toxicity in pregnant mice exposed daily during either the period of major organogenesis (gestation days [GD] 8-12) or fetal growth (GD13-17). Endpoints include clinical signs of toxicity, serum analyses to evaluate hepatic and renal function, histopathology of liver and kidney, and hematology. Study animals were administered 50 μg/kg CYN once daily by ip route and euthanized 24 h after 1, 2, 3, 4, or 5 consecutive doses, or 6 or 13 d after the dosing period. The course of the CYN-induced effects was determined at all euthanasia times for the endpoints just outlined. Results indicated that CYN is a toxin, producing lethality in dams during the early part of gestation, significant weight loss, and bleeding in the gastrointestinal tract, tail tip, and peri-orbital tissues. Effects also included alterations in serum markers for liver function, histopathological changes in liver and kidney tissues, electrolyte abnormalities, leukocytosis, and posttreatment thrombocytopenia and reticulocytosis. The onset of symptoms was rapid, producing reductions in weight gain in GD8-12 animals, bleeding in the vaginal area in GD13-17 animals, and significant increases in sorbitol dehydrogenase (SDH) in both groups after a single dose. Although the GD8-12 dams displayed a 50% lethality, in GD13-17 animals only a single death occurred. Alterations seen in hepatic and renal function or histopathology do not appear to be of sufficient severity to produce death. Evidence indicates that bleeding may play a critical role in the onset of symptoms and eventually, in the observed lethality.

  13. The removal of endocrine disrupting compounds, pharmaceutically activated compounds and cyanobacterial toxins during drinking water preparation using activated carbon--a review.

    PubMed

    Delgado, Luis F; Charles, Philippe; Glucina, Karl; Morlay, Catherine

    2012-10-01

    This paper provides a review of recent scientific research on the removal by activated carbon (AC) in drinking water (DW) treatment of 1) two classes of currently unregulated trace level contaminants with potential chronic toxicity-pharmaceutically activate compounds (PhACs) and endocrine disrupting compounds (EDCs); 2) cyanobacterial toxins (CyBTs), which are a group of highly toxic and regulated compounds (as microcystin-LR); and 3) the above mentioned compounds by the hybrid system powdered AC/membrane filtration. The influence of solute and AC properties, as well as the competitive effect from background natural organic matter on the adsorption of such trace contaminants, are also considered. In addition, a number of adsorption isotherm parameters reported for PhACs, EDCs and CyBTs are presented herein. AC adsorption has proven to be an effective removal process for such trace contaminants without generating transformation products. This process appears to be a crucial step in order to minimize PhACs, EDCs and CyBTs in finished DW, hence calling for further studies on AC adsorption removal of these compounds. Finally, a priority chart of PhACs and EDCs warranting further study for the removal by AC adsorption is proposed based on the compounds' structural characteristics and their low removal by AC compared to the other compounds.

  14. Variable Cyanobacterial Toxin and Metabolite  Profiles across Six Eutrophic Lakes of Differing  Physiochemical Characteristics.

    PubMed

    Beversdorf, Lucas J; Weirich, Chelsea A; Bartlett, Sarah L; Miller, Todd R

    2017-02-10

    Future sustainability of freshwater resources is seriously threatened due to the presence  of  harmful  cyanobacterial  blooms,  and  yet,  the  number,  extent,  and  distribution  of  most  cyanobacterial toxins-including "emerging" toxins and other bioactive compounds-are poorly  understood.  We  measured  15  cyanobacterial  compounds-including  four  microcystins  (MC),  saxitoxin (SXT), cylindrospermopsin (CYL), anatoxin-a (ATX) and homo-anatoxin-a (hATX), two  anabaenopeptins (Apt), three cyanopeptolins (Cpt), microginin (Mgn), and nodularin (NOD)-in  six freshwater lakes that regularly experience noxious cHABs. MC, a human liver toxin, was present  in all six lakes and was detected in 80% of all samples. Similarly, Apt, Cpt, and Mgn were detected  in all lakes in roughly 86%, 50%, and 35% of all samples, respectively. Despite being a notable  brackish  water  toxin,  NOD  was  detected  in  the  two  shallowest  lakes-Wingra  (4.3  m)  and  Koshkonong (2.1 m). All compounds were highly variable temporally, and spatially. Metabolite  profiles were significantly different between lakes suggesting lake characteristics influenced the  cyanobacterial community and/or metabolite production. Understanding how cyanobacterial toxins  are  distributed  across  eutrophic  lakes  may  shed  light  onto  the  ecological  function  of  these  metabolites, provide valuable information for their remediation and removal, and aid in the  protection of public health.

  15. Single and combined exposure to MC-LR and BMAA confirm suitability of Aegagropila linnaei for use in green liver systems(®)-A case study with cyanobacterial toxins.

    PubMed

    Contardo-Jara, Valeska; Kuehn, Sandra; Pflugmacher, Stephan

    2015-08-01

    The filamentous green algae Aegagropila linnaei was tested for its uptake capacity of the cyanobacterial toxins microcystin-LR (MC-LR) and β-N-methylamino-l-alanine (BMAA) in order to approve the suitability of its use in the Green Liver System(®). Uptake into the algae and toxin reduction in the medium were analyzed by LC-MS/MS after static exposure for one week to 20μgL(-1) MC-LR, 80μgL(-1) BMAA, and 20μgL(-1) MC-LR together with 80μgL(-1) BMAA, respectively. BMAA was effectively removed by A. linnaei within 5 days compared to only around 35% removal of the initial exposure concentration in the case of MC-LR, independent of the application mode, in single or in a mixture. However, differences were found for BMAA amounts taken up into the tissue in that it was higher if applied in combination with MC-LR. Additionally, physiological responses such as the activity of biotransformation enzyme glutathione S-transferase (GST), antioxidant enzymes peroxidase (POD) and catalase (CAT) as well as the development of the reactive oxygen species hydrogen peroxide (H2O2) were compared between the different treatment groups in order to determine possible harmful effects of the toxin exposure on the algae. In contrast to the toxin exposure to a single toxin with no significant enzymatic response, exposure to the toxin mixture provoked an immediate increase in GST and CAT activity after one day as well as after longer exposure for one week, hinting on an enhanced need for prevention against exposure derived reactive oxygen species as well as putative biotransformation attempts in a mixture exposure scenario.

  16. Destruction of cyanobacterial toxin cylindrospermopsin by hydroxyl radicals and sulfate radicals using UV-254 nm activation of hydrogen peroxide, persulfate and peroxymonosulfate

    EPA Science Inventory

    Abstract: With increasing worldwide incidence of toxic cyanobacterial blooms in bodies of water, cylindrospermopsin (CYN) has become a significant concern to public health and water management officials. In this study, the removal of CYN by UV-254 nm-mediated advanced oxidation ...

  17. The integration of nutrients, cyanobacterial biomass and ...

    EPA Pesticide Factsheets

    This presentation is an integrated evaluation of cyanobacterial growth and toxin production, from a reservoir through drinking water treatment - where biomass and toxin removal are achieved. Data is generated by a variety of methods: online instrumentation for chlorophyll, dissolved oxygen, temperature and pH; enzyme linked immune substrate (ELISA) and liquid chromatography/mass spectrometric (LC/MS) methods for toxin analysis; microscopic methods for species identification; quantitative PCR methods for species identification; and bench-scale engineering studies for removal of toxins and biomass through drinking water treatment. This presentation is an integrated evaluation of cyanobacterial growth and toxin production, from a reservoir through drinking water treatment. The content will be useful for EPA regional office staff, state primacy personnel, state and local health personnel, drinking water treatment managers and consulting engineers.

  18. Ecotoxicological effects of selected cyanobacterial secondary metabolites a short review

    SciTech Connect

    Wiegand, C. . E-mail: cwiegand@igb-berlin.de; Pflugmacher, S. . E-mail: pflugmacher@igb-berlin.de

    2005-03-15

    Cyanobacteria are one of the most diverse groups of gram-negative photosynthetic prokaryotes. Many of them are able to produce a wide range of toxic secondary metabolites. These cyanobacterial toxins can be classified in five different groups: hepatotoxins, neurotoxins, cytotoxins, dermatotoxins, and irritant toxins (lipopolysaccharides). Cyanobacterial blooms are hazardous due to this production of secondary metabolites and endotoxins, which could be toxic to animals and plants. Many of the freshwater cyanobacterial blooms include species of the toxigenic genera Microcystis, Anabaena, or Plankthotrix. These compounds differ in mechanisms of uptake, affected organs, and molecular mode of action. In this review, the main focus is the aquatic environment and the effects of these toxins to the organisms living there. Some basic toxic mechanisms will be discussed in comparison to the mammalian system.

  19. Quality measures of imaging mass spectrometry aids in revealing long-term striatal protein changes induced by neonatal exposure to the cyanobacterial toxin β-N-methylamino-L-alanine (BMAA).

    PubMed

    Karlsson, Oskar; Bergquist, Jonas; Andersson, Malin

    2014-01-01

    Many pathological processes are not directly correlated to dramatic alterations in protein levels. The changes in local concentrations of important proteins in a subset of cells or at specific loci are likely to play a significant role in disease etiologies, but the precise location might be unknown, or the concentration might be too small to be adequately sampled for traditional proteomic techniques. Matrix-assisted laser desorption ionization (MALDI) imaging mass spectrometry (IMS) is a unique analytical method that combines analysis of multiple molecular species and of their distribution in a single platform. As reproducibility is essential for successful biomarker discovery, it is important to systematically assess data quality in biologically relevant MALDI IMS experiments. In the present study, we applied four simple tools to study the reproducibility for individual sections, within-group variation, and between-group variation of data acquired from brain sections of 21 animals divided into three treatment groups. We also characterized protein changes in distinct regions of the striatum from six-month-old rats treated neonatally (postnatal days 9-10) with the cyanobacterial toxin β-N-methylamino-l-alanine (BMAA), which has been implicated in neurodegenerative diseases. The results showed that optimized experimental settings can yield high-quality MALDI IMS data with relatively low variation (14% to 15% coefficient of variance) that allow the characterization of subtle changes in protein expression in various subregions of the brain. This was further exemplified by the dose-dependent reduction of myelin basic protein in the caudate putamen and the nucleus accumbens of adult rats neonatally treated with BMAA (150 and 460 mg/kg). The reduction in myelin basic protein was confirmed through immunohistochemistry and indicates that developmental exposure to BMAA may induce structural effects on axonal growth and/or directly on the proliferation of oligodendrocytes

  20. Status, Alert System, and Prediction of Cyanobacterial Bloom in South Korea

    PubMed Central

    Srivastava, Ankita; Ahn, Chi-Yong; Asthana, Ravi Kumar; Lee, Hyung-Gwan; Oh, Hee-Mock

    2015-01-01

    Bloom-forming freshwater cyanobacterial genera pose a major ecological problem due to their ability to produce toxins and other bioactive compounds, which can have important implications in illnesses of humans and livestock. Cyanobacteria such as Microcystis, Anabaena, Oscillatoria, Phormidium, and Aphanizomenon species producing microcystins and anatoxin-a have been predominantly documented from most South Korean lakes and reservoirs. With the increase in frequency of such blooms, various monitoring approaches, treatment processes, and prediction models have been developed in due course. In this paper we review the field studies and current knowledge on toxin producing cyanobacterial species and ecological variables that regulate toxin production and bloom formation in major rivers (Han, Geum, Nakdong, and Yeongsan) and reservoirs in South Korea. In addition, development of new, fast, and high-throughput techniques for effective monitoring is also discussed with cyanobacterial bloom advisory practices, current management strategies, and their implications in South Korean freshwater bodies. PMID:25705675

  1. Cyanobacterial Neurotoxin BMAA and Mercury in Sharks.

    PubMed

    Hammerschlag, Neil; Davis, David A; Mondo, Kiyo; Seely, Matthew S; Murch, Susan J; Glover, William Broc; Divoll, Timothy; Evers, David C; Mash, Deborah C

    2016-08-16

    Sharks have greater risk for bioaccumulation of marine toxins and mercury (Hg), because they are long-lived predators. Shark fins and cartilage also contain β-N-methylamino-l-alanine (BMAA), a ubiquitous cyanobacterial toxin linked to neurodegenerative diseases. Today, a significant number of shark species have found their way onto the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. Many species of large sharks are threatened with extinction due in part to the growing high demand for shark fin soup and, to a lesser extent, for shark meat and cartilage products. Recent studies suggest that the consumption of shark parts may be a route to human exposure of marine toxins. Here, we investigated BMAA and Hg concentrations in fins and muscles sampled in ten species of sharks from the South Atlantic and Pacific Oceans. BMAA was detected in all shark species with only seven of the 55 samples analyzed testing below the limit of detection of the assay. Hg concentrations measured in fins and muscle samples from the 10 species ranged from 0.05 to 13.23 ng/mg. These analytical test results suggest restricting human consumption of shark meat and fins due to the high frequency and co-occurrence of two synergistic environmental neurotoxic compounds.

  2. Cyanobacterial Neurotoxin BMAA and Mercury in Sharks

    PubMed Central

    Hammerschlag, Neil; Davis, David A.; Mondo, Kiyo; Seely, Matthew S.; Murch, Susan J.; Glover, William Broc; Divoll, Timothy; Evers, David C.; Mash, Deborah C.

    2016-01-01

    Sharks have greater risk for bioaccumulation of marine toxins and mercury (Hg), because they are long-lived predators. Shark fins and cartilage also contain β-N-methylamino-l-alanine (BMAA), a ubiquitous cyanobacterial toxin linked to neurodegenerative diseases. Today, a significant number of shark species have found their way onto the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. Many species of large sharks are threatened with extinction due in part to the growing high demand for shark fin soup and, to a lesser extent, for shark meat and cartilage products. Recent studies suggest that the consumption of shark parts may be a route to human exposure of marine toxins. Here, we investigated BMAA and Hg concentrations in fins and muscles sampled in ten species of sharks from the South Atlantic and Pacific Oceans. BMAA was detected in all shark species with only seven of the 55 samples analyzed testing below the limit of detection of the assay. Hg concentrations measured in fins and muscle samples from the 10 species ranged from 0.05 to 13.23 ng/mg. These analytical test results suggest restricting human consumption of shark meat and fins due to the high frequency and co-occurrence of two synergistic environmental neurotoxic compounds. PMID:27537913

  3. THE TRPV1 RECEPTOR: THE INTERAGENCY, INTERNATION SYMPOSIUM ON CYANOBACTERIAL HARMFUL ALGAL BLOOMS.

    EPA Science Inventory

    Background and Significance

    Evidence indicates that the frequency of occurrence of cyanobacterial harmful algal blooms (CHABs) is increasing in spatial and temporal extent in the US and worldwide. Cyanotoxins are among the most potent toxins known, causing death through ...

  4. Application of cellular biosensors for detection of atypical toxic bioactivity in microcystin-containing cyanobacterial extracts.

    PubMed

    Mankiewicz-Boczek, Joanna; Karwaciak, Iwona; Ratajewski, Marcin; Gągała, Ilona; Jurczak, Tomasz; Zalewski, Maciej; Pułaski, Łukasz

    2015-11-01

    Despite the focus of most ecotoxicological studies on cyanobacteria on a select group of cyanotoxins, especially microcystins, a growing body of evidence points to the involvement of other cyanobacterial metabolites in deleterious health effects. In the present study, original, self-developed reporter gene-based cellular biosensors, detecting activation of the main human xenobiotic stress response pathways, PXR and NFkappaB, were applied to detect novel potentially toxic bioactivities in extracts from freshwater microcystin-producing cyanobacterial blooms. Crude and purified extracts from cyanobacteria containing varying levels of microcystins, and standard microcystin-LR were tested. Two cellular biosensor types applied in this study, called NHRTOX (detecting PXR activation) and OXIBIOS (detecting NFkappaB activation), successfully detected potentially toxic or immunomodulating bioactivities in cyanobacterial extracts. The level of biosensor activation was comparable to control cognate environmental toxins. Despite the fact that extracts were derived from microcystin-producing cyanobacterial blooms and contained active microcystins, biosensor-detected bioactivities were shown to be unrelated to microcystin levels. Experimental results suggest the involvement of environmental toxins (causing a response in NHRTOX) and lipopolysaccharides (LPS) or other cell wall components (causing a response in OXIBIOS) in the potentially harmful bioactivity of investigated extracts. These results demonstrate the need for further identification of cyanobacterial metabolites other than commonly studied cyanotoxins as sources of health risk, show the usefulness of cellular biosensors for this purpose and suggest a novel, more holistic approach to environmental monitoring.

  5. Molecular characterization of cyanobacterial diversity in Lake Gregory, Sri Lanka

    NASA Astrophysics Data System (ADS)

    Magana-Arachchi, Dhammika; Wanigatunge, Rasika; Liyanage, Madhushankha

    2011-07-01

    Eutrophication or the process of nutrient enrichment of stagnant waters due to excessive use of fertilizer is becoming a critical issue worldwide. Lake Gregory, an artificial lake situated in Nuwara Eliya, Sri Lanka was once a very attractive landscape feature and recreational area attracting a large number of visitors. Rapid urbanization in surrounding areas and the consequent intensification of agricultural and industrial activities led to eutrophication and siltation in the lake. Present study was conducted to detect cyanobacterial diversity and their ability to produce hepatotoxic microcystins using polymerase chain reaction (PCR)-based techniques. Twenty five water samples (surface and bottom) were collected from the lake and total nitrogen and total carbon were estimated. Cyanobacterial cultures were grown in appropriate media and microscopic observations were used to determine the morphological diversity of cyanobacteria isolated from different sites. Genomic DNA was isolated and purified from cyanobacteria using Boom's method. DNA samples were analyzed by PCR with oligonucleotide primers for 16S rRNA gene and mcyA gene of the operon that encodes a microcystin synthetase. The 16S rRNA gene sequences revealed the presences of cyanobacteria belong to Synechococcus sp., Microcystis aeruginosa, Calothrix sp., Leptolyngbya sp., Limnothrix sp., order Oscillatoriales and order Chroococcales. The sequences obtained from this study were deposited in the database under the accession numbers (GenBank: GU368104-GU368116). PCR amplification of mcyA primers indicated the potential for toxin formation of isolated M. aeruginosa from Lake Gregory. This preliminary study shows that the Lake Gregory is under the potential risk of cyanobacterial toxicity. Clearly more work is needed to extend this finding and clarify if other cyanobacterial isolates have genetic potential to produce microcystin since this lake is utilized for recreational activities.

  6. Toxicity of harmful cyanobacterial blooms to bream and roach.

    PubMed

    Trinchet, Isabelle; Cadel-Six, Sabrina; Djediat, Chakib; Marie, Benjamin; Bernard, Cécile; Puiseux-Dao, Simone; Krys, Sophie; Edery, Marc

    2013-09-01

    Aquatic ecosystems are facing increasing environmental pressures, leading to an increasing frequency of cyanobacterial Harmful Algal Blooms (cHABs) that have emerged as a worldwide concern due to their growing frequency and their potential toxicity to the fauna that threatens the functioning of ecosystems. Cyanobacterial blooms raise concerns due to the fact that several strains produce potent bioactive or toxic secondary metabolites, such as the microcystins (MCs), which are hepatotoxic to vertebrates. These strains of cyanobacteria may be potentially toxic to fish via gastrointestinal ingestion and also by direct absorption of the toxin MC from the water. The purpose of our study was to investigate toxic effects observed in fish taken from several lakes in the Ile-de-France region, where MCs-producing blooms occur. This study comprises histological studies and the measurement of MC concentrations in various organs. The histological findings are similar to those obtained following laboratory exposure of medaka fish to MCs: hepatic lesions predominate and include cell lysis and cell detachment. MC concentrations in the organs revealed that accumulation was particularly high in the digestive tract and the liver, which are known to be classical targets of MCs. In contrast concentrations were very low in the muscles. Differences in the accumulation of MC variants produced by blooms indicate that in order to more precisely evaluate the toxic potential of a specific bloom it is necessary not only to consider the concentration of toxins, but also the variants produced.

  7. The Role of Nitrogen Fixation in Cyanobacterial Bloom Toxicity in a Temperate, Eutrophic Lake

    PubMed Central

    Beversdorf, Lucas J.; Miller, Todd R.; McMahon, Katherine D.

    2013-01-01

    Toxic cyanobacterial blooms threaten freshwaters worldwide but have proven difficult to predict because the mechanisms of bloom formation and toxin production are unknown, especially on weekly time scales. Water quality management continues to focus on aggregated metrics, such as chlorophyll and total nutrients, which may not be sufficient to explain complex community changes and functions such as toxin production. For example, nitrogen (N) speciation and cycling play an important role, on daily time scales, in shaping cyanobacterial communities because declining N has been shown to select for N fixers. In addition, subsequent N pulses from N2 fixation may stimulate and sustain toxic cyanobacterial growth. Herein, we describe how rapid early summer declines in N followed by bursts of N fixation have shaped cyanobacterial communities in a eutrophic lake (Lake Mendota, Wisconsin, USA), possibly driving toxic Microcystis blooms throughout the growing season. On weekly time scales in 2010 and 2011, we monitored the cyanobacterial community in a eutrophic lake using the phycocyanin intergenic spacer (PC-IGS) region to determine population dynamics. In parallel, we measured microcystin concentrations, N2 fixation rates, and potential environmental drivers that contribute to structuring the community. In both years, cyanobacterial community change was strongly correlated with dissolved inorganic nitrogen (DIN) concentrations, and Aphanizomenon and Microcystis alternated dominance throughout the pre-toxic, toxic, and post-toxic phases of the lake. Microcystin concentrations increased a few days after the first significant N2 fixation rates were observed. Then, following large early summer N2 fixation events, Microcystis increased and became most abundant. Maximum microcystin concentrations coincided with Microcystis dominance. In both years, DIN concentrations dropped again in late summer, and N2 fixation rates and Aphanizomenon abundance increased before the lake mixed in

  8. Effect of Environmental Factors on Cyanobacterial Abundance and Cyanotoxins Production in Natural and Drinking Water, Bangladesh.

    PubMed

    Affan, Abu; Khomavis, Hisham S; Al-Harbi, Salim Marzoog; Haque, Mahfuzul; Khan, Saleha

    2015-02-01

    Cyanobacterial blooms commonly appear during the summer months in ponds, lakes and reservoirs in Bangladesh. In these areas, fish mortality, odorous water and fish and human skin irritation and eye inflammation have been reported. The influence of physicochemical factors on the occurrence of cyanobacteria and its toxin levels were evaluated in natural and drinking water in Bangladesh. A highly sensitive immunosorbent assay was used to detect microcystins (MCs). Cyanobacteria were found in 22 of 23 samples and the dominant species were Microcystis aeruginosa, followed by Microcystisflosaquae, Anabeana crassa and Aphanizomenon flosaquae. Cyanobacterial abundance varied from 39 to 1315 x 10(3) cells mL(-1) in natural water and 31 to 49 x 10(3) cells mL(-1) in tap water. MC concentrations were 25-82300 pg mL(-1) with the highest value measured in the fish research pond, followed by Ishakha Lake. In tap water, MC concentrations ranged from 30-32 pg mL(-1). The correlation between nitrate-nitrogen (NO3-N) concentration and cyanobacterial cell abundance was R2 = 0.62 while that between cyanobacterial abundance and MC concentration was R2 = 0.98. The increased NO3-N from fish feed, organic manure, poultry and dairy farm waste and fertilizer from agricultural land eutrophicated the water bodies and triggered cyanobacterial bloom formation. The increased amount of cyanobacteria produced MCs, subsequently reducing the water quality.

  9. Cyanobacteria, Toxins and Indicators: Full-Scale Monitoring & Bench-Scale Treatment Studies

    EPA Science Inventory

    Summary of: 1) Lake Erie 2014 bloom season full-scale treatment plant monitoring data for cyanobacteria and cyanobacteria toxins; 2) Follow-up work to examine the impact of pre-oxidation on suspensions of intact toxin-producing cyanobacterial cells.

  10. Toxic cyanobacterial breakthrough and accumulation in a drinking water plant: a monitoring and treatment challenge.

    PubMed

    Zamyadi, Arash; MacLeod, Sherri L; Fan, Yan; McQuaid, Natasha; Dorner, Sarah; Sauvé, Sébastien; Prévost, Michèle

    2012-04-01

    The detection of cyanobacteria and their associated toxins has intensified in recent years in both drinking water sources and the raw water of drinking water treatment plants (DWTPs). The objectives of this study were to: 1) estimate the breakthrough and accumulation of toxic cyanobacteria in water, scums and sludge inside a DWTP, and 2) to determine whether chlorination can be an efficient barrier to the prevention of cyanotoxin breakthrough in drinking water. In a full scale DWTP, the fate of cyanobacteria and their associated toxins was studied after the addition of coagulant and powdered activated carbon, post clarification, within the clarifier sludge bed, after filtration and final chlorination. Elevated cyanobacterial cell numbers (4.7 × 10(6)cells/mL) and total microcystins concentrations (up to 10 mg/L) accumulated in the clarifiers of the treatment plant. Breakthrough of cells and toxins in filtered water was observed. Also, a total microcystins concentration of 2.47 μg/L was measured in chlorinated drinking water. Cyanobacterial cells and toxins from environmental bloom samples were more resistant to chlorination than results obtained using laboratory cultured cells and dissolved standard toxins.

  11. Cyanobacterial evolution during the Precambrian

    NASA Astrophysics Data System (ADS)

    Schirrmeister, Bettina E.; Sanchez-Baracaldo, Patricia; Wacey, David

    2016-07-01

    Life on Earth has existed for at least 3.5 billion years. Yet, relatively little is known of its evolution during the first two billion years, due to the scarceness and generally poor preservation of fossilized biological material. Cyanobacteria, formerly known as blue green algae were among the first crown Eubacteria to evolve and for more than 2.5 billion years they have strongly influenced Earth's biosphere. Being the only organism where oxygenic photosynthesis has originated, they have oxygenated Earth's atmosphere and hydrosphere, triggered the evolution of plants -being ancestral to chloroplasts- and enabled the evolution of complex life based on aerobic respiration. Having such a strong impact on early life, one might expect that the evolutionary success of this group may also have triggered further biosphere changes during early Earth history. However, very little is known about the early evolution of this phylum and ongoing debates about cyanobacterial fossils, biomarkers and molecular clock analyses highlight the difficulties in this field of research. Although phylogenomic analyses have provided promising glimpses into the early evolution of cyanobacteria, estimated divergence ages are often very uncertain, because of vague and insufficient tree-calibrations. Results of molecular clock analyses are intrinsically tied to these prior calibration points, hence improving calibrations will enable more precise divergence time estimations. Here we provide a review of previously described Precambrian microfossils, biomarkers and geochemical markers that inform upon the early evolution of cyanobacteria. Future research in micropalaeontology will require novel analyses and imaging techniques to improve taxonomic affiliation of many Precambrian microfossils. Consequently, a better understanding of early cyanobacterial evolution will not only allow for a more specific calibration of cyanobacterial and eubacterial phylogenies, but also provide new dates for the tree

  12. POTENTIAL DEVELOPMENTAL TOXICITY OF ANATOXIN-A, A CYANOBACTERIAL TOXIN

    EPA Science Inventory

    Anatoxin-a acts as a neuro-muscular blocking agent. Acute toxicity is characterized by rapid onset of paralysis, tremors, convulsions, and death. Human exposures may occur from recreational water activities and dietary supplements, but are primarily through drinking water. The...

  13. Occurrence, Monitoring and Treatment of Cyanobacterial Toxins in Drinking Water

    EPA Science Inventory

    In the summer of 2014 a number of drinking water treatment plants (DWTPs) on Lake Erie supplied water samples on a monthly basis for analysis. Chlorophyll-a measurements, LC/MS/MS and ELISA techniques specific to microcystins were employed to measure potential harmful algal bloom...

  14. Cyanotoxin mixtures and taste-and-odor compounds in cyanobacterial blooms from the midwestern united states

    USGS Publications Warehouse

    Graham, J.L.; Loftin, K.A.; Meyer, M.T.; Ziegler, A.C.

    2010-01-01

    The mixtures of toxins and taste-and-odor compounds present during cyanobacterial blooms are not well characterized and of particular concern when evaluating potential human health risks. Cyanobacterial blooms were sampled in twenty-three Midwestern United States lakes and analyzed for community composition, thirteen cyanotoxins by liquid chromatography/mass spectrometry and immunoassay, and two taste-and-odor compounds by gas chromatography/mass spectrometry. Aphanizomenon, Cylindrospermopsis and/or Microcystis were dominant in most (96%) blooms, but community composition was not strongly correlated with toxin and taste-and-odor occurrence. Microcystins occurred in all blooms. Total microcystin concentrations measured by liquid chromatography/mass spectrometry and immunoassay were linearly related (rs = 0.76, p < 0.01) and LC/MS/MS concentrations were lower than or similar to ELISA in most (85%) samples. Geosmin (87%), 2-methylisoborneol (39%), anatoxin-a (30%), saxitoxins (17%), cylindrospermopsins (9%), and nodularin-R (9%) also were present in these blooms. Multiple classes of cyanotoxins occurred in 48% of blooms and 95% had multiple microcystin variants. Toxins and taste-and-odor compounds frequently co-occurred (91% of blooms), indicating odor may serve as a warning that cyanotoxins likely are present. However, toxins occurred more frequently than taste-and-odor compounds, so odor alone does not provide sufficient warning to ensure human-health protection. ?? This article not subject to U.S. Copyright. Published 2010 by the American Chemical Society.

  15. Could the presence of larger fractions of non-cyanobacterial species be used as a predictor of microcystin production under variable nutrient regimes?

    PubMed

    Sinang, Som Cit; Reichwaldt, Elke S; Ghadouani, Anas

    2015-07-01

    The occurrence of cyanobacteria and microcystin is highly dynamic in natural environments and poses one of the biggest challenges to water resource management. While a number of drivers are known to be responsible for the occurrence of cyanobacterial blooms, the drivers of microcystin production are not adequately known. This study aims to quantify the effects of the changes in the structures of phytoplankton and cyanobacterial communities on the dynamics of microcystin production under highly variable nutrient concentration. In our study, nutrient variability could explain 64% of the variability in microcystin production. When changes in the fractions of non-cyanobacteria versus cyanobacteria genera were additionally included, 80% of the variability in microcystin production could be explained; under high nutrient concentrations, non-cyanobacterial phytoplankton groups were dominant over cyanobacteria and cyanobacteria produced more toxins. In contrast, changes in the cyanobacterial community structures could only explain a further 4% of the dynamics of microcystin production. As such, the dominance of non-cyanobacterial groups appears to be a useful factor to explain microcystin occurrence in addition to traditionally used factors such as absolute cyanobacterial cell numbers, especially when the nutrient regime is taken into account. This information could help to further refine the risk assessment frameworks which are currently used to manage the risk posed by cyanobacterial blooms.

  16. Appendages of the cyanobacterial cell.

    PubMed

    Schuergers, Nils; Wilde, Annegret

    2015-03-04

    Extracellular non-flagellar appendages, called pili or fimbriae, are widespread in gram-negative bacteria. They are involved in many different functions, including motility, adhesion, biofilm formation, and uptake of DNA. Sequencing data for a large number of cyanobacterial genomes revealed that most of them contain genes for pili synthesis. However, only for a very few cyanobacteria structure and function of these appendages have been analyzed. Here, we review the structure and function of type IV pili in Synechocystis sp. PCC 6803 and analyze the distribution of type IV pili associated genes in other cyanobacteria. Further, we discuss the role of the RNA-chaperone Hfq in pilus function and the presence of genes for the chaperone-usher pathway of pilus assembly in cyanobacteria.

  17. The effects of various control and water treatment processes on the membrane integrity and toxin fate of cyanobacteria.

    PubMed

    Fan, Jiajia; Hobson, Peter; Ho, Lionel; Daly, Robert; Brookes, Justin

    2014-01-15

    Cyanobacterial blooms are one of the main contaminants that can degrade drinking water quality with the associated taste, odour and toxic compounds. Although a wide range of techniques have shown promise for cyanobacterial bloom control and cyanobacterial cell/metabolite removal in reservoirs and water treatment plants (WTPs), these treatments may have negative consequences through release of intracellular metabolites into the surrounding water. This study assessed the impact of copper sulphate (CuSO4), chlorine, potassium permanganate (KMnO4), hydrogen peroxide (H2O2) and ozone on Microcystis aeruginosa culture and the toxins it produced. All of these agents induced the loss of cyanobacterial membrane integrity. However, no associated increase in dissolved toxins was detected during chlorine and H2O2 treatments which may be due to faster toxin oxidation rates than release rates. KMnO4 doses of 1 and 3mgL(-1) degraded dissolved toxins while having no impact on cyanobacterial membrane integrity. In contrast, ozone induced a significant increase in extracellular toxins but it was unable to degrade these toxins to the same degree as the other oxidants which may due to the lack of residual. All chemicals, except CuSO4, were able to reduce cyanotoxins and chlorine was the most effective with a rate up to 2161M(-1)s(-1).

  18. Gasification of cyanobacterial in supercritical water.

    PubMed

    Zhang, Huiwen; Zhu, Wei; Xu, Zhirong; Gong, Miao

    2014-01-01

    Cyanobacterial collected from eutrophic freshwater lakes constituted intractable waste with a rich algae biomass content. Supercritical water gasification (SCWG) was proposed to treat the cyanobacterial and to produce hydrogen for energy. The H 2 yield reached 2.92 mol/kg at reaction conditions of 500 °C, 30 min and 22 MPa; this yield accounted for 26% of the total gaseous products. Abundant ammonia and dissolved reactive phosphorous were concentrated in the liquid product, which could be recovered and used as a liquid fertilizer. Solid residue, which accounted only for about 1% of the wet weight, was mainly composed of coke and ash. The efficiency of H 2 production was better than that from other biomass, because of the abundant organic matter in cyanobacterial. Thus, cyanobacterial are an ideal biomass feedstock for H 2 production from SCWG.

  19. Structure and Effects of Cyanobacterial Lipopolysaccharides

    PubMed Central

    Durai, Prasannavenkatesh; Batool, Maria; Choi, Sangdun

    2015-01-01

    Lipopolysaccharide (LPS) is a component of the outer membrane of mainly Gram-negative bacteria and cyanobacteria. The LPS molecules from marine and terrestrial bacteria show structural variations, even among strains within the same species living in the same environment. Cyanobacterial LPS has a unique structure, since it lacks heptose and 3-deoxy-d-manno-octulosonic acid (also known as keto-deoxyoctulosonate (KDO)), which are present in the core region of common Gram-negative LPS. In addition, the cyanobacterial lipid A region lacks phosphates and contains odd-chain hydroxylated fatty acids. While the role of Gram-negative lipid A in the regulation of the innate immune response through Toll-like Receptor (TLR) 4 signaling is well characterized, the role of the structurally different cyanobacterial lipid A in TLR4 signaling is not well understood. The uncontrolled inflammatory response of TLR4 leads to autoimmune diseases such as sepsis, and thus the less virulent marine cyanobacterial LPS molecules can be effective to inhibit TLR4 signaling. This review highlights the structural comparison of LPS molecules from marine cyanobacteria and Gram-negative bacteria. We discuss the potential use of marine cyanobacterial LPS as a TLR4 antagonist, and the effects of cyanobacterial LPS on humans and marine organisms. PMID:26198237

  20. Structure and Effects of Cyanobacterial Lipopolysaccharides.

    PubMed

    Durai, Prasannavenkatesh; Batool, Maria; Choi, Sangdun

    2015-07-07

    Lipopolysaccharide (LPS) is a component of the outer membrane of mainly Gram-negative bacteria and cyanobacteria. The LPS molecules from marine and terrestrial bacteria show structural variations, even among strains within the same species living in the same environment. Cyanobacterial LPS has a unique structure, since it lacks heptose and 3-deoxy-d-manno-octulosonic acid (also known as keto-deoxyoctulosonate (KDO)), which are present in the core region of common Gram-negative LPS. In addition, the cyanobacterial lipid A region lacks phosphates and contains odd-chain hydroxylated fatty acids. While the role of Gram-negative lipid A in the regulation of the innate immune response through Toll-like Receptor (TLR) 4 signaling is well characterized, the role of the structurally different cyanobacterial lipid A in TLR4 signaling is not well understood. The uncontrolled inflammatory response of TLR4 leads to autoimmune diseases such as sepsis, and thus the less virulent marine cyanobacterial LPS molecules can be effective to inhibit TLR4 signaling. This review highlights the structural comparison of LPS molecules from marine cyanobacteria and Gram-negative bacteria. We discuss the potential use of marine cyanobacterial LPS as a TLR4 antagonist, and the effects of cyanobacterial LPS on humans and marine organisms.

  1. Symbiotic adaptation drives genome streamlining of the cyanobacterial sponge symbiont "Candidatus Synechococcus spongiarum".

    PubMed

    Gao, Zhao-Ming; Wang, Yong; Tian, Ren-Mao; Wong, Yue Him; Batang, Zenon B; Al-Suwailem, Abdulaz M; Bajic, Vladimir B; Qian, Pei-Yuan

    2014-04-01

    "Candidatus Synechococcus spongiarum" is a cyanobacterial symbiont widely distributed in sponges, but its functions at the genome level remain unknown. Here, we obtained the draft genome (1.66 Mbp, 90% estimated genome recovery) of "Ca. Synechococcus spongiarum" strain SH4 inhabiting the Red Sea sponge Carteriospongia foliascens. Phylogenomic analysis revealed a high dissimilarity between SH4 and free-living cyanobacterial strains. Essential functions, such as photosynthesis, the citric acid cycle, and DNA replication, were detected in SH4. Eukaryoticlike domains that play important roles in sponge-symbiont interactions were identified exclusively in the symbiont. However, SH4 could not biosynthesize methionine and polyamines and had lost partial genes encoding low-molecular-weight peptides of the photosynthesis complex, antioxidant enzymes, DNA repair enzymes, and proteins involved in resistance to environmental toxins and in biosynthesis of capsular and extracellular polysaccharides. These genetic modifications imply that "Ca. Synechococcus spongiarum" SH4 represents a low-light-adapted cyanobacterial symbiont and has undergone genome streamlining to adapt to the sponge's mild intercellular environment. IMPORTANCE Although the diversity of sponge-associated microbes has been widely studied, genome-level research on sponge symbionts and their symbiotic mechanisms is rare because they are unculturable. "Candidatus Synechococcus spongiarum" is a widely distributed uncultivated cyanobacterial sponge symbiont. The genome of this symbiont will help to characterize its evolutionary relationship and functional dissimilarity to closely related free-living cyanobacterial strains. Knowledge of its adaptive mechanism to the sponge host also depends on the genome-level research. The data presented here provided an alternative strategy to obtain the draft genome of "Ca. Synechococcus spongiarum" strain SH4 and provide insight into its evolutionary and functional features.

  2. Benthic Marine Cyanobacterial Mat Ecosystems: Biogeochemistry and Biomarkers

    NASA Technical Reports Server (NTRS)

    DesMarais, David J.; DeVincenzi, Donald (Technical Monitor)

    2001-01-01

    Cyanobacterial mats are complete ecosystems that can include processes of primary production, diagenesis and lithification. Light sustains oxygenic photosynthesis, which in turn provides energy, organic matter and oxygen to the community. Due to both absorption and scattering phenomena, incident light is transformed with depth in the mat, both in intensity and spectral composition. Mobile photo synthesizers optimize their position with respect to this light gradient. When photosynthesis ceases at night, the upper layers of the mat become reduced and sulfidic. Counteracting gradients of oxygen and sulfide combine to provide daily-contrasting environments separated on a scale of a few mm. The functional complexity of mats, coupled with the highly proximal and ordered spatial arrangement of biota, offers the potential for a staggering number of interactions. At a minimum, the products of each functional group of microorganisms affect the other groups both positively and negatively. For example, cyanobacteria generate organic matter (potential substrates) but also oxygen (a toxin for many anaerobes). Anaerobic activity recycles nutrients to the photosynthesizers but also generates potentially toxic sulfide. The combination of benefits and hazards of light, oxygen and sulfide promotes the allocation of the various essential mat processes between light and dark periods, and to various depths in the mat. Observations of mats have produced numerous surprises. For example, obligately anaerobic processes can occur in the presence of abundant oxygen, highly reduced gases are produced in the presence of abundant sulfate, meiofauna thrive at high sulfide concentrations, and the mats' constituent populations respond to environmental changes in complex ways. While photosynthetic bacteria dominate the biomass and productivity of the mat, nonphotosynthetic, anaerobic processes constitute the ultimate biological filter on the ecosystem's emergent biosignatures, including those

  3. Stool C difficile toxin

    MedlinePlus

    Antibiotic associated colitis - toxin; Colitis - toxin; Pseudomembranous - toxin; Necrotizing colitis - toxin; C difficile - toxin ... provider thinks that diarrhea is caused by the antibiotic medicines you have taken recently. Antibiotics change the ...

  4. Pertussis toxin

    SciTech Connect

    Sekura, R.D.; Moss, J.; Vaughan, M.

    1985-01-01

    This book contains 13 selections. Some of the titles are: Genetic and Functional Studies of Pertussis Toxin Substrates; Effect of Pertussis Toxin on the Hormonal Responsiveness of Different Tissues; Extracellular Adenylate Cyclase of Bordetella pertussis; and GTP-Regulatory Proteins are Introcellular Messagers: A Model for Hormone Action.

  5. Trophic state and geographic gradients influence planktonic cyanobacterial diversity and distribution in New Zealand lakes.

    PubMed

    Wood, Susanna A; Maier, Marcia Y; Puddick, Jonathan; Pochon, Xavier; Zaiko, Anastasija; Dietrich, Daniel R; Hamilton, David P

    2017-02-01

    Cyanobacteria are commonly associated with eutrophic lakes, where they often form blooms and produce toxins. However, they are a ubiquitous component of phytoplankton in lakes of widely varying trophic status. We hypothesised that cyanobacterial diversity would vary among lakes of differing trophic status, but that the relative importance of geographical and hydromorphological characteristics driving these patterns would differ across trophic groups. DNA from 143 New Zealand lakes that spanned a range of geographic, hydromorphological and trophic gradients was analysed using automated rRNA intergenic spacer analysis and screened for genes involved in cyanotoxin production. Statistical analysis revealed significant delineation among cyanobacterial communities from different trophic classes. Multivariate regression indicated that geographical features (latitude, longitude and altitude) were significant in driving cyanobacterial community structure; however, partitioning of their effects varied among trophic categories. High-throughput sequencing was undertaken on selected samples to investigate their taxonomic composition. The most abundant and diverse (71 operational taxonomic units) taxon across all lake types was the picocyanobacteria genus Synechococcus Cyanotoxins (microcystins n = 23, anatoxins n = 1) were only detected in eutrophic lowland lakes. Collectively, these data infer that increasing eutrophication of lakes will have broad-scale impacts on planktonic cyanobacteria diversity and the prevalence of cyanotoxins.

  6. Cyanobacterial KnowledgeBase (CKB), a Compendium of Cyanobacterial Genomes and Proteomes

    PubMed Central

    Mohandass, Shylajanaciyar; Varadharaj, Sangeetha; Thilagar, Sivasudha; Abdul Kareem, Kaleel Ahamed; Dharmar, Prabaharan; Gopalakrishnan, Subramanian; Lakshmanan, Uma

    2015-01-01

    Cyanobacterial KnowledgeBase (CKB) is a free access database that contains the genomic and proteomic information of 74 fully sequenced cyanobacterial genomes belonging to seven orders. The database also contains tools for sequence analysis. The Species report and the gene report provide details about each species and gene (including sequence features and gene ontology annotations) respectively. The database also includes cyanoBLAST, an advanced tool that facilitates comparative analysis, among cyanobacterial genomes and genomes of E. coli (prokaryote) and Arabidopsis (eukaryote). The database is developed and maintained by the Sub-Distributed Informatics Centre (sponsored by the Department of Biotechnology, Govt. of India) of the National Facility for Marine Cyanobacteria, a facility dedicated to marine cyanobacterial research. CKB is freely available at http://nfmc.res.in/ckb/index.html. PMID:26305368

  7. Potent toxins in Arctic environments--presence of saxitoxins and an unusual microcystin variant in Arctic freshwater ecosystems.

    PubMed

    Kleinteich, Julia; Wood, Susanna A; Puddick, Jonathan; Schleheck, David; Küpper, Frithjof C; Dietrich, Daniel

    2013-11-25

    Cyanobacteria are the predominant phototrophs in freshwater ecosystems of the polar regions where they commonly form extensive benthic mats. Despite their major biological role in these ecosystems, little attention has been paid to their physiology and biochemistry. An important feature of cyanobacteria from the temperate and tropical regions is the production of a large variety of toxic secondary metabolites. In Antarctica, and more recently in the Arctic, the cyanobacterial toxins microcystin and nodularin (Antarctic only) have been detected in freshwater microbial mats. To date other cyanobacterial toxins have not been reported from these locations. Five Arctic cyanobacterial communities were screened for saxitoxin, another common cyanobacterial toxin, and microcystins using immunological, spectroscopic and molecular methods. Saxitoxin was detected for the first time in cyanobacteria from the Arctic. In addition, an unusual microcystin variant was identified using liquid chromatography-mass spectrometry. Gene expression analyses confirmed the analytical findings, whereby parts of the sxt and mcy operon involved in saxitoxin and microcystin synthesis, were detected and sequenced in one and five of the Arctic cyanobacterial samples, respectively. The detection of these compounds in the cryosphere improves the understanding of the biogeography and distribution of toxic cyanobacteria globally. The sequences of sxt and mcy genes provided from this habitat for the first time may help to clarify the evolutionary origin of toxin production in cyanobacteria.

  8. Cyanobacterial Toxic and Bioactive Peptides in Freshwater Bodies of Greece: Concentrations, Occurrence Patterns, and Implications for Human Health.

    PubMed

    Gkelis, Spyros; Lanaras, Thomas; Sivonen, Kaarina

    2015-10-12

    Cyanobacterial harmful algal blooms represent one of the most conspicuous waterborne microbial hazards in aquatic environments mostly due to the production of toxic secondary metabolites, mainly microcystins (MCs). Other bioactive peptides are frequently found in cyanobacterial blooms, yet their concentration and ecological relevance is still unknown. In this paper we studied the presence and concentration of cyanobacterial peptides (microcystins, anabaenopeptins, anabaenopeptilides) in 36 Greek freshwater bodies, using HPLC-DAD, ELISA, and PP1IA. Microcystins were found in more than 90% of the samples investigated, indicating that microcystin-producing strains seem to also occur in lakes without blooms. Microcystins MC-RR, MC-LR, and MC-YR were the main toxin constituents of the bloom samples. Anabaenopeptin A and B were predominant in some samples, whereas anabaenopeptolide 90A was the only peptide found in Lake Mikri Prespa. The intracellular concentrations of anabaenopeptins produced by cyanobacterial bloom populations are determined for the first time in this study; the high (>1000 µg·L(-1)) anabaenopeptin concentration found indicates there may be some impacts, at least on the ecology and the food web structure of the aquatic ecosystems. The maximum intracellular MC values measured in Lakes Kastoria and Pamvotis, exceeding 10,000 µg·L(-1), are among the highest reported.

  9. Toxic Cyanobacterial Bloom Triggers in Missisquoi Bay, Lake Champlain, as Determined by Next-Generation Sequencing and Quantitative PCR

    PubMed Central

    Fortin, Nathalie; Munoz-Ramos, Valentina; Bird, David; Lévesque, Benoît; Whyte, Lyle G.; Greer, Charles W.

    2015-01-01

    Missisquoi Bay (MB) is a temperate eutrophic freshwater lake that frequently experiences toxic Microcystis-dominated cyanobacterial blooms. Non-point sources are responsible for the high concentrations of phosphorus and nitrogen in the bay. This study combined data from environmental parameters, E. coli counts, high-throughput sequencing of 16S rRNA gene amplicons, quantitative PCR (16S rRNA and mcyD genes) and toxin analyses to identify the main bloom-promoting factors. In 2009, nutrient concentrations correlated with E. coli counts, abundance of total cyanobacterial cells, Microcystis 16S rRNA and mcyD genes and intracellular microcystin. Total and dissolved phosphorus also correlated significantly with rainfall. The major cyanobacterial taxa were members of the orders Chroococcales and Nostocales. The genus Microcystis was the main mcyD-carrier and main microcystin producer. Our results suggested that increasing nutrient concentrations and total nitrogen:total phosphorus (TN:TP) ratios approaching 11:1, coupled with an increase in temperature, promoted Microcystis-dominated toxic blooms. Although the importance of nutrient ratios and absolute concentrations on cyanobacterial and Microcystis dynamics have been documented in other laboratories, an optimum TN:TP ratio for Microcystis dominance has not been previously observed in situ. This observation provides further support that nutrient ratios are an important determinant of species composition in natural phytoplankton assemblages. PMID:25984732

  10. Comparative summer dynamics of surface cyanobacterial communities in two connected lakes from the west of Ireland.

    PubMed

    Touzet, N; McCarthy, D; Gill, A; Fleming, G T A

    2016-05-15

    The eutrophication of lakes is typically associated with high biomass proliferations of potentially toxic cyanobacteria. At a regional level, the sustainable management of water resources necessitates an approach that recognises the interconnectivity of multiple water systems within river catchments. This study examined the dynamics in summer diversity of planktonic cyanobacterial communities and microcystin toxin concentrations in two inter-connected lakes from the west of Ireland prone to nutrient enrichment. DGGE analysis of 16S rRNA gene amplicons of genotype-I cyanobacteria (typically spherical) showed changes in the communities of both Lough Corrib and Ballyquirke Lough throughout the summer, and identified cyanobacterial genotypes both unique and shared to both lakes. Microcystin concentrations, estimated via the protein phosphatase 2A inhibition assay, were greater in August than in July and June in both lakes. This was concomitant to the increased occurrence of Microcystis as evidenced by DGGE band excision and subsequent sequencing and BLAST analysis. RFLP analysis of PCR amplified mcy-A/E genes clustered together the August samples of both lakes, highlighting a potential change in microcystin producers across the two lakes. Finally, the multiple factor analysis of the combined environmental data set for the two lakes highlighted the expected pattern opposing greater water temperature and chlorophyll concentration against macronutrient concentrations, but also indicated a negative relationship between microcystin concentration and cyanobacterial diversity, possibly underlining allelopathic interactions. Despite some element of connectivity, the dissimilarity in the composition of the cyanobacterial assemblages and the timing of community change in the two lakes likely were a reflexion of niche differences determined by meteorologically-forced variation in physico-chemical parameters in the two water bodies.

  11. Are cyanobacterial blooms trophic dead ends?

    PubMed

    Perga, Marie-Elodie; Domaizon, Isabelle; Guillard, Jean; Hamelet, Valérie; Anneville, Orlane

    2013-06-01

    Cyanobacterial blooms induce significant costs that are expected to increase in the near future. Cyanobacterial resistance to zooplankton grazing is one factor thought to promote bloom events. Yet, numerous studies on zooplankton ability to graze upon cyanobacteria have been producing contradictory results and such a puzzle might arise from the lack of direct observations in situ. Our objective was to track, using fatty acid (FA) and fatty acid stable isotope analyses (FA-SIA), the fate of cyanobacterial organic matter in the food web of a lake subjected to summer blooms of Planktothrix rubescens. A metalimnetic bloom of P. rubescens occurred in Lake Bourget (France) during the study period (May-November 2009). The bloom was especially rich in α-linolenic acid, 18:3(n-3), but none of the considered zooplankton taxa exhibited spiking content in this particular FA. FA-SIA revealed, however, that over a quarter of 18:3(n-3) in small zooplankton (<500 μm) was provided by P. rubescens while large cladocerans (>500 μm) did not benefit from it. P. rubescens 18:3(n-3) could be tracked up to perch (Perca fluviatilis) young of the year (YOY) to which it contributed to ~15 % of total 18:3(n-3). Although transferred with a much lower efficiency than micro-algal organic matter, the P. rubescens bloom supported a significant share of the pelagic secondary production and did not constitute, sensu stricto, a 'trophic dead end'. The cyanobacterial bloom also provided perch YOY with components of high nutritional values at a season when these are critical for their recruitment. This cyanobacterial bloom might thus be regarded as a significant dietary bonus for juvenile fish.

  12. Evaluation of usefulness of Microbial Assay for Risk Assessment (MARA) in the cyanobacterial toxicity estimation.

    PubMed

    Sieroslawska, Anna

    2014-07-01

    The aim of the study was to elucidate the usefulness of the Microbial Assay for Risk Assessment (MARA) to evaluate toxicity in samples containing cyanobacterial products. Cyanobacterial extracts with different cyanotoxin contents and pure cyanotoxins-microcystin-LR, cylindrospermopsin and anatoxin-a-were tested. On the basis of the microbial reaction, MARA indicated only slight or no toxicity in the studied extracts. Similarly, no or low toxicity of pure toxins was detected at the concentrations used (up to 10 μg/ml). Weak relationships between the reactions of individual organisms exposed to cyanotoxin-containing extracts and to the same pure toxins were observed. On the other hand, inhibition of some organisms, such as Pichia anomalia, whose growth was not impacted by pure cyanotoxins, indicated the presence of other biologically active compounds in the studied extracts. In conclusion, MARA assay is not enough sensitive to be used as a good tool for cyanotoxin screening. It may, however, be applied in searching for antimicrobial/antifungal cyanobacteria-derived compounds.

  13. The dual role of nitrogen supply in controlling the growth and toxicity of cyanobacterial blooms.

    PubMed

    Gobler, Christopher J; Burkholder, JoAnn M; Davis, Timothy W; Harke, Matthew J; Johengen, Tom; Stow, Craig A; Van de Waal, Dedmer B

    2016-04-01

    Historically, phosphorus (P) has been considered the primary limiting nutrient for phytoplankton assemblages in freshwater ecosystems. This review, supported by new findings from Lake Erie, highlights recent molecular, laboratory, and field evidence that the growth and toxicity of some non-diazotrophic blooms of cyanobacteria can be controlled by nitrogen (N). Cyanobacteria such as Microcystis possess physiological adaptations that allow them to dominate low-P surface waters, and in temperate lakes, cyanobacterial densities can be controlled by N availability. Beyond total cyanobacterial biomass, N loading has been shown to selectively promote the abundance of Microcystis and Planktothrix strains capable of synthesizing microcystins over strains that do not possess this ability. Among strains of cyanobacteria capable of synthesizing the N-rich microcystins, cellular toxin quotas have been found to depend upon exogenous N supplies. Herein, multi-year observations from western Lake Erie are presented demonstrating that microcystin concentrations peak in parallel with inorganic N, but not orthophosphate, concentrations and are significantly lower (p<0.01) during years of reduced inorganic nitrogen loading and concentrations. Collectively, this information underscores the importance of N as well as P in controlling toxic cyanobacteria blooms. Furthermore, it supports the premise that management actions to reduce P in the absence of concurrent restrictions on N loading may not effectively control the growth and/or toxicity of non-diazotrophic toxic cyanobacteria such as the cosmopolitan, toxin-producing genus, Microcystis.

  14. A synopsis of research needs identified at the Interagency, International Symposium on Cyanobacterial Harmful Algal Blooms (ISOC-HAB).

    PubMed

    Hudnell, H Kenneth; Dortch, Quay

    2008-01-01

    Evidence indicates that the incidence of cyanobacterial harmful algal blooms (CHABs) is increasing in spatial extent and temporal frequency worldwide. Cyanobacterial blooms produce highly potent toxins and huge, noxious biomasses in surface Waters used for recreation, commerce, and as drinking water sources. The Interagency, International Symposium on Cyanobacterial Harmful Algal Blooms (ISOC-HAB) characterized the state of the science and identified research needed to address the risks posed by CHABs to human health and ecosystem sustainability. This chapter provides a synopsis of CHAB research needs that were identified by workgroups that addressed charges in major topic areas. The research and infrastructure needed are listed under nine categories: 1) Analytical Methods; 2) CHAB Occurrence; 3) CHAB Causes; 4) Human Health; 5) Ecosystem Sustainability; 6) CHAB Prevention; 7) CHAB Control and Mitigation; 8) Risk Assessment and; 9) Infrastructure. A number of important issues must be addressed to successfully confront the health, ecologic, and economic challenges presented by CHABs. Near-term research goals include the development of field-ready tests to identify and quantify cells and toxins, the production of certified reference standards and bulk toxins, formal assessments of CHAB incidence, improved understanding of toxin effects, therapeutic interventions, ecologically benign means to prevent and control CHABs, supplemental drinking water treatment techniques, and the development of risk assessment and management strategies. Long-term goals include the assimilation of CHAB databases into emerging U.S. and international observing systems, the development of quantitative models to predict CHAB occurrence, effects, and management outcomes, and economic analyses of CAHB costs and management benefits. Accomplishing further infrastructure development and freshwater HAB research is discussed in relationship to the Harmful Algal Blooms and Hypoxia Research and Control

  15. Engineered Transcriptional Systems for Cyanobacterial Biotechnology

    PubMed Central

    Camsund, Daniel; Lindblad, Peter

    2014-01-01

    Cyanobacteria can function as solar-driven biofactories thanks to their ability to perform photosynthesis and the ease with which they are genetically modified. In this review, we discuss transcriptional parts and promoters available for engineering cyanobacteria. First, we go through special cyanobacterial characteristics that may impact engineering, including the unusual cyanobacterial RNA polymerase, sigma factors and promoter types, mRNA stability, circadian rhythm, and gene dosage effects. Then, we continue with discussing component characteristics that are desirable for synthetic biology approaches, including decoupling, modularity, and orthogonality. We then summarize and discuss the latest promoters for use in cyanobacteria regarding characteristics such as regulation, strength, and dynamic range and suggest potential uses. Finally, we provide an outlook and suggest future developments that would advance the field and accelerate the use of cyanobacteria for renewable biotechnology. PMID:25325057

  16. Cyanobacterial genomics for ecology and biotechnology.

    PubMed

    Hess, Wolfgang R

    2011-10-01

    Cyanobacteria are the only prokaryotes that directly convert solar energy and CO(2) into organic matter by oxygenic photosynthesis, explaining their relevance for primary production in many ecosystems and the increasing interest for biotechnology. At present, there are more than 60 cyanobacteria for which a total genome sequence is publicly available. These cyanobacteria belong to different lifestyles and origins, coming from marine and freshwater aquatic environments, as well as terrestrial and symbiotic habitats. Genome sizes vary by a factor of six, from 1.44 Mb to 9.05 Mb, with the number of reported genes ranging from 1241 to 8462. Several studies have demonstrated how these sequences could be used to successfully infer important ecological, physiological and biotechnologically relevant characteristics. However, sequences of cyanobacterial origin also comprise a significant portion of certain metagenomes. Moreover, genome analysis has been employed for culture-independent approaches and for resequencing mutant strains, a very recent tool in cyanobacterial research.

  17. Proteomic approaches in research of cyanobacterial photosynthesis.

    PubMed

    Battchikova, Natalia; Angeleri, Martina; Aro, Eva-Mari

    2015-10-01

    Oxygenic photosynthesis in cyanobacteria, algae, and plants is carried out by a fabulous pigment-protein machinery that is amazingly complicated in structure and function. Many different approaches have been undertaken to characterize the most important aspects of photosynthesis, and proteomics has become the essential component in this research. Here we describe various methods which have been used in proteomic research of cyanobacteria, and demonstrate how proteomics is implemented into on-going studies of photosynthesis in cyanobacterial cells.

  18. Eukaryotes in Arctic and Antarctic cyanobacterial mats.

    PubMed

    Jungblut, Anne D; Vincent, Warwick F; Lovejoy, Connie

    2012-11-01

    Cyanobacterial mats are commonly found in freshwater ecosystems throughout the polar regions. Most mats are multilayered three-dimensional structures with the filamentous cyanobacteria embedded in a gel-like matrix. Although early descriptions mentioned the presence of larger organisms including metazoans living in the mats, there have been few studies specifically focused on the microbial eukaryotes, which are often small cells with few morphological features suitable for identification by microscopy. Here, we applied 18S rRNA gene clone library analysis to identify eukaryotes in cyanobacterial mat communities from both the Antarctic and the extreme High Arctic. We identified 39 ribotypes at the level of 99% sequence similarity. These consisted of taxa within algal and other protist groups including Chlorophyceae, Prasinophyceae, Ulvophyceae, Trebouxiophyceae, Bacillariophyceae, Chrysophyceae, Ciliophora, and Cercozoa. Fungi were also recovered, as were 21 metazoan ribotypes. The eukaryotic taxa appeared habitat-specific with little overlap between lake, pond, and ice shelf communities. Some ribotypes were common to both Arctic and Antarctic mats, suggesting global dispersal of these taxa and similarity in the environmental filters acting on protist communities. Many of these eukaryotic taxa likely benefit from protected, nutrient-rich microhabitats within the cyanobacterial mat environment.

  19. Harmful cyanobacterial blooms: causes, consequences, and controls.

    PubMed

    Paerl, Hans W; Otten, Timothy G

    2013-05-01

    Cyanobacteria are the Earth's oldest oxygenic photoautotrophs and have had major impacts on shaping its biosphere. Their long evolutionary history (≈ 3.5 by) has enabled them to adapt to geochemical and climatic changes, and more recently anthropogenic modifications of aquatic environments, including nutrient over-enrichment (eutrophication), water diversions, withdrawals, and salinization. Many cyanobacterial genera exhibit optimal growth rates and bloom potentials at relatively high water temperatures; hence global warming plays a key role in their expansion and persistence. Bloom-forming cyanobacterial taxa can be harmful from environmental, organismal, and human health perspectives by outcompeting beneficial phytoplankton, depleting oxygen upon bloom senescence, and producing a variety of toxic secondary metabolites (e.g., cyanotoxins). How environmental factors impact cyanotoxin production is the subject of ongoing research, but nutrient (N, P and trace metals) supply rates, light, temperature, oxidative stressors, interactions with other biota (bacteria, viruses and animal grazers), and most likely, the combined effects of these factors are all involved. Accordingly, strategies aimed at controlling and mitigating harmful blooms have focused on manipulating these dynamic factors. The applicability and feasibility of various controls and management approaches is discussed for natural waters and drinking water supplies. Strategies based on physical, chemical, and biological manipulations of specific factors show promise; however, a key underlying approach that should be considered in almost all instances is nutrient (both N and P) input reductions; which have been shown to effectively reduce cyanobacterial biomass, and therefore limit health risks and frequencies of hypoxic events.

  20. Health-based cyanotoxin guideline values allow for cyanotoxin-based monitoring and efficient public health response to cyanobacterial blooms.

    PubMed

    Farrer, David; Counter, Marina; Hillwig, Rebecca; Cude, Curtis

    2015-02-05

    Human health risks from cyanobacterial blooms are primarily related to cyanotoxins that some cyanobacteria produce. Not all species of cyanobacteria can produce toxins. Those that do often do not produce toxins at levels harmful to human health. Monitoring programs that use identification of cyanobacteria genus and species and enumeration of cyanobacterial cells as a surrogate for cyanotoxin presence can overestimate risk and lead to unnecessary health advisories. In the absence of federal criteria for cyanotoxins in recreational water, the Oregon Health Authority (OHA) developed guideline values for the four most common cyanotoxins in Oregon's fresh waters (anatoxin-a, cylindrospermopsin, microcystins, and saxitoxins). OHA developed three guideline values for each of the cyanotoxins found in Oregon. Each of the guideline values is for a specific use of cyanobacteria-affected water: drinking water, human recreational exposure and dog recreational exposure. Having cyanotoxin guidelines allows OHA to promote toxin-based monitoring (TBM) programs, which reduce the number of health advisories and focus advisories on times and places where actual, rather than potential, risks to health exist. TBM allows OHA to more efficiently protect public health while reducing burdens on local economies that depend on water recreation-related tourism.

  1. Health-Based Cyanotoxin Guideline Values Allow for Cyanotoxin-Based Monitoring and Efficient Public Health Response to Cyanobacterial Blooms

    PubMed Central

    Farrer, David; Counter, Marina; Hillwig, Rebecca; Cude, Curtis

    2015-01-01

    Human health risks from cyanobacterial blooms are primarily related to cyanotoxins that some cyanobacteria produce. Not all species of cyanobacteria can produce toxins. Those that do often do not produce toxins at levels harmful to human health. Monitoring programs that use identification of cyanobacteria genus and species and enumeration of cyanobacterial cells as a surrogate for cyanotoxin presence can overestimate risk and lead to unnecessary health advisories. In the absence of federal criteria for cyanotoxins in recreational water, the Oregon Health Authority (OHA) developed guideline values for the four most common cyanotoxins in Oregon’s fresh waters (anatoxin-a, cylindrospermopsin, microcystins, and saxitoxins). OHA developed three guideline values for each of the cyanotoxins found in Oregon. Each of the guideline values is for a specific use of cyanobacteria-affected water: drinking water, human recreational exposure and dog recreational exposure. Having cyanotoxin guidelines allows OHA to promote toxin-based monitoring (TBM) programs, which reduce the number of health advisories and focus advisories on times and places where actual, rather than potential, risks to health exist. TBM allows OHA to more efficiently protect public health while reducing burdens on local economies that depend on water recreation-related tourism. PMID:25664510

  2. Botulinum Toxin

    DTIC Science & Technology

    2009-01-01

    resulting from antibiotic treatment (Cherington, 1998). Foodbome and inhalational have noninfectious etiologies and are the result of ingesting or...infants Self- Antibiotic -treated All exposed All exposed individuals Patients treated with local toxin injections (2 to 4 months of age) prior to...typically take place except under circumstances where the normal flora has been altered by antibiotic treatment (Cherington, 1998). Botulism results

  3. Cyanobacterial chassis engineering for enhancing production of biofuels and chemicals.

    PubMed

    Gao, Xinyan; Sun, Tao; Pei, Guangsheng; Chen, Lei; Zhang, Weiwen

    2016-04-01

    To reduce dependence on fossil fuels and curb greenhouse effect, cyanobacteria have emerged as an important chassis candidate for producing biofuels and chemicals due to their capability to directly utilize sunlight and CO2 as the sole energy and carbon sources, respectively. Recent progresses in developing and applying various synthetic biology tools have led to the successful constructions of novel pathways of several dozen green fuels and chemicals utilizing cyanobacterial chassis. Meanwhile, it is increasingly recognized that in order to enhance productivity of the synthetic cyanobacterial systems, optimizing and engineering more robust and high-efficient cyanobacterial chassis should not be omitted. In recent years, numerous research studies have been conducted to enhance production of green fuels and chemicals through cyanobacterial chassis modifications involving photosynthesis, CO2 uptake and fixation, products exporting, tolerance, and cellular regulation. In this article, we critically reviewed recent progresses and universal strategies in cyanobacterial chassis engineering to make it more robust and effective for bio-chemicals production.

  4. Legionella Toxin.

    DTIC Science & Technology

    1981-04-29

    of a cytotoxin produced by Legionella pneumophila. Infect. Immun. 29:271-274. Fumarola, D. (1978) Legionnaires ’ disease agent and Limulus endotoxin... Legionnaires ’ disease bacterium in the AKR/J mouse. Ann. intern. Med. 90:676-679. Hedlund, K. W. and Larson, R. (1981) Legionella pneumophila toxin, isolation... Legionella Species New Name Old Name Lpneumophila Legionnaires ’ disease organism, OLDA L. bozemanil WIGA, MI 15 L. dumoffii NY 23, TEX-KL *L. micdadei

  5. Evidence of freshwater algal toxins in marine shellfish: Implications for human and aquatic health.

    PubMed

    Gibble, Corinne M; Peacock, Melissa B; Kudela, Raphael M

    2016-11-01

    The occurrence of freshwater harmful algal bloom toxins impacting the coastal ocean is an emerging threat, and the potential for invertebrate prey items to concentrate toxin and cause harm to human and wildlife consumers is not yet fully recognized. We examined toxin uptake and release in marine mussels for both particulate and dissolved phases of the hepatotoxin microcystin, produced by the freshwater cyanobacterial genus Microcystis. We also extended our experimental investigation of particulate toxin to include oysters (Crassostrea sp.) grown commercially for aquaculture. California mussels (Mytilus californianus) and oysters were exposed to Microcystis and microcystin toxin for 24h at varying concentrations, and then were placed in constantly flowing seawater and sampled through time simulating riverine flushing events to the coastal ocean. Mussels exposed to particulate microcystin purged the toxin slowly, with toxin detectable for at least 8 weeks post-exposure and maximum toxin of 39.11ng/g after exposure to 26.65μg/L microcystins. Dissolved toxin was also taken up by California mussels, with maximum concentrations of 20.74ng/g after exposure to 7.74μg/L microcystin, but was purged more rapidly. Oysters also took up particulate toxin but purged it more quickly than mussels. Additionally, naturally occurring marine mussels collected from San Francisco Bay tested positive for high levels of microcystin toxin. These results suggest that ephemeral discharge of Microcystis or microcystin to estuaries and the coastal ocean accumulate in higher trophic levels for weeks to months following exposure.

  6. Cyanobacterial Neurotoxin β-N-Methylamino-L-alanine (BMAA) in Shark Fins

    PubMed Central

    Mondo, Kiyo; Hammerschlag, Neil; Basile, Margaret; Pablo, John; Banack, Sandra A.; Mash, Deborah C.

    2012-01-01

    Sharks are among the most threatened groups of marine species. Populations are declining globally to support the growing demand for shark fin soup. Sharks are known to bioaccumulate toxins that may pose health risks to consumers of shark products. The feeding habits of sharks are varied, including fish, mammals, crustaceans and plankton. The cyanobacterial neurotoxin β-N-methylamino-L-alanine (BMAA) has been detected in species of free-living marine cyanobacteria and may bioaccumulate in the marine food web. In this study, we sampled fin clips from seven different species of sharks in South Florida to survey the occurrence of BMAA using HPLC-FD and Triple Quadrupole LC/MS/MS methods. BMAA was detected in the fins of all species examined with concentrations ranging from 144 to 1836 ng/mg wet weight. Since BMAA has been linked to neurodegenerative diseases, these results may have important relevance to human health. We suggest that consumption of shark fins may increase the risk for human exposure to the cyanobacterial neurotoxin BMAA. PMID:22412816

  7. Cyanobacterial neurotoxin β-N-methylamino-L-alanine (BMAA) in shark fins.

    PubMed

    Mondo, Kiyo; Hammerschlag, Neil; Basile, Margaret; Pablo, John; Banack, Sandra A; Mash, Deborah C

    2012-02-01

    Sharks are among the most threatened groups of marine species. Populations are declining globally to support the growing demand for shark fin soup. Sharks are known to bioaccumulate toxins that may pose health risks to consumers of shark products. The feeding habits of sharks are varied, including fish, mammals, crustaceans and plankton. The cyanobacterial neurotoxin β-N-methylamino-L-alanine (BMAA) has been detected in species of free-living marine cyanobacteria and may bioaccumulate in the marine food web. In this study, we sampled fin clips from seven different species of sharks in South Florida to survey the occurrence of BMAA using HPLC-FD and Triple Quadrupole LC/MS/MS methods. BMAA was detected in the fins of all species examined with concentrations ranging from 144 to 1836 ng/mg wet weight. Since BMAA has been linked to neurodegenerative diseases, these results may have important relevance to human health. We suggest that consumption of shark fins may increase the risk for human exposure to the cyanobacterial neurotoxin BMAA.

  8. Microcystin accumulation and biochemical responses in the edible clam Corbiculaleana P. exposed to cyanobacterial crude extract.

    PubMed

    Pham, Thanh-Luu; Shimizu, Kazuya; Kanazawa, Ayako; Gao, Yu; Dao, Thanh-Son; Utsumi, Motoo

    2016-06-01

    We investigated the accumulation and effects of cyanobacterial crude extract (CCE) containing microcystins (MCs) on the edible clam Corbiculaleana P. Toxic effects were evaluated through the activity of antioxidant and detoxification enzymes: catalase (CAT), superoxide dismutase (SOD), and glutathione-S-transferases (GSTs) from gills, foot, mantle and remaining soft tissues. Clams were exposed to CCE containing 400μg MC-LReq/L for 10days and were then kept in toxin-free water for 5days. Clam accumulated MCs (up to 3.41±0.63μg/g dry weight (DW) of unbound MC and 0.31±0.013μg/g DW of covalently bound MC). Detoxification and antioxidant enzymes in different organs responded differently to CCE during the experiment. The activity of SOD, CAT, and GST in the gills and mantle increased in MC-treated clams. In contrast, CAT and GST activity was significantly inhibited in the foot and mostly only slightly changed in the remaining tissues. The responses of biotransformation, antioxidant enzyme activity to CCE and the fast elimination of MCs during depuration help to explain how the clam can survive for long periods (over a week) during the decay of toxic cyanobacterial blooms in nature.

  9. CYANOCHIP: an antibody microarray for high-taxonomical-resolution cyanobacterial monitoring.

    PubMed

    Blanco, Yolanda; Quesada, Antonio; Gallardo-Carreño, Ignacio; Aguirre, Jacobo; Parro, Victor

    2015-02-03

    Cyanobacteria are Gram-negative photosynthetic prokaryotes that are widespread on Earth. Eutrophication and global warming make some aquatic ecosystems behave as bioreactors that trigger rapid and massive cyanobacterial growth with remarkable economic and health consequences. Rapid and efficient early warning systems are required to support decisions by water body authorities. We have produced 17 specific antibodies to the most frequent cyanobacterial strains blooming in freshwater ecosystems, some of which are toxin producers. A sandwich-type antibody microarray immunoassay (CYANOCHIP) was developed for the simultaneous testing of any of the 17 strains, or other closely related strains, in field samples from different habitats (water, rocks, and sediments). We titrated and tested all of the antibodies in succession using a fluorescent sandwich microarray immunoassay. Although most showed high specificity, we applied a deconvolution method based on graph theory to disentangle the few existing cross-reactions. The CYANOCHIP sensitivity ranged from 10(2) to 10(4) cells mL(-1), with most antibodies detecting approximately 10(2) cells mL(-1). We validated the system by testing multiple isolates and crude natural samples from freshwater reservoirs and rocks, both in the laboratory and by in situ testing in the field. The results demonstrated that CYANOCHIP is a valuable tool for the sensitive and reliable detection of cyanobacteria for early warning and research purposes.

  10. Metatranscriptomic Evidence for Co-Occurring Top-Down and Bottom-Up Controls on Toxic Cyanobacterial Communities

    PubMed Central

    Steffen, Morgan M.; Belisle, B. Shafer; Watson, Sue B.; Boyer, Gregory L.; Bourbonniere, Richard A.

    2015-01-01

    Little is known about the molecular and physiological function of co-occurring microbes within freshwater cyanobacterial harmful algal blooms (cHABs). To address this, community metatranscriptomes collected from the western basin of Lake Erie during August 2012 were examined. Using sequence data, we tested the hypothesis that the activity of the microbial community members is independent of community structure. Predicted metabolic and physiological functional profiles from spatially distinct metatranscriptomes were determined to be ≥90% similar between sites. Targeted analysis of Microcystis aeruginosa, the historical causative agent of cyanobacterial harmful algal blooms over the past ∼20 years, as well as analysis of Planktothrix agardhii and Anabaena cylindrica, revealed ongoing transcription of genes involved in microcystin toxin synthesis as well as the acquisition of both nitrogen and phosphorus, nutrients often implicated as independent bottom-up drivers of eutrophication in aquatic systems. Transcription of genes involved in carbon dioxide (CO2) concentration and metabolism also provided support for the alternate hypothesis that high-pH conditions and dense algal biomass result in CO2-limiting conditions that further favor cyanobacterial dominance. Additionally, the presence of Microcystis-specific cyanophage sequences provided preliminary evidence of possible top-down virus-mediated control of cHAB populations. Overall, these data provide insight into the complex series of constraints associated with Microcystis blooms that dominate the western basin of Lake Erie during summer months, demonstrating that multiple environmental factors work to shape the microbial community. PMID:25662977

  11. Molecular biology of cyanobacterial salt acclimation.

    PubMed

    Hagemann, Martin

    2011-01-01

    High and changing salt concentrations represent major abiotic factors limiting the growth of microorganisms. During their long evolution, cyanobacteria have adapted to aquatic habitats with various salt concentrations. High salt concentrations in the medium challenge the cell with reduced water availability and high contents of inorganic ions. The basic mechanism of salt acclimation involves the active extrusion of toxic inorganic ions and the accumulation of compatible solutes, including sucrose, trehalose, glucosylglycerol, and glycine betaine. The kinetics of these physiological processes has been exceptionally well studied in the model Synechocystis 6803, leading to the definition of five subsequent phases in reaching a new salt acclimation steady state. Recent '-omics' technologies using the advanced model Synechocystis 6803 have revealed a comprehensive picture of the dynamic process of salt acclimation involving the differential expression of hundreds of genes. However, the mechanisms involved in sensing specific salt stress signals are not well resolved. In the future, analysis of cyanobacterial salt acclimation will be directed toward defining the functions of the many unknown proteins upregulated in salt-stressed cells, identifying specific salt-sensing mechanisms, using salt-resistant strains of cyanobacteria for the production of bioenergy, and applying cyanobacterial stress genes to improve the salt tolerance of sensitive organisms.

  12. Quantifying Phycocyanin Concentration in Cyanobacterial Algal Blooms from Remote Sensing Reflectance-A Quasi Analytical Approach

    NASA Astrophysics Data System (ADS)

    Mishra, S.; Mishra, D. R.; Tucker, C.

    2011-12-01

    Cyanobacterial harmful algal blooms (CHAB) are notorious for depleting dissolved oxygen level, producing various toxins, causing threats to aquatic life, altering the food-web dynamics and the overall ecosystem functioning in inland lakes, estuaries, and coastal waters. Most of these algal blooms produce various toxins that can damage cells, tissues and even cause mortality of living organisms. Frequent monitoring of water quality in a synoptic scale has been possible by the virtue of remote sensing techniques. In this research, we present a novel technique to monitor CHAB using remote sensing reflectance products. We have modified a multi-band quasi analytical algorithm that determines phytoplankton absorption coefficients from above surface remote sensing reflectance measurements using an inversion method. In situ hyperspectral remote sensing reflectance data were collected from several highly turbid and productive aquaculture ponds. A novel technique was developed to further decompose the phytoplankton absorption coefficients at 620 nm and obtain phycocyanin absorption coefficient at the same wavelength. An empirical relationship was established between phycocyanin absorption coefficients at 620 nm and measured phycocyanin concentrations. Model calibration showed strong relationship between phycocyanin absorption coefficients and phycocyanin pigment concentration (r2=0.94). Validation of the model in a separate dataset produced a root mean squared error of 167 mg m-3 (phycocyanin range: 26-1012 mg m-3). Results demonstrate that the new approach will be suitable for quantifying phycocyanin concentration in cyanobacteria dominated turbid productive waters. Band architecture of the model matches with the band configuration of the Medium Resolution Imaging Spectrometer (MERIS) and assures that MERIS reflectance products can be used to quantify phycocyanin in cyanobacterial harmful algal blooms in optically complex waters.

  13. Diversity and Impact of Prokaryotic Toxins on Aquatic Environments: A Review

    PubMed Central

    Valério, Elisabete; Chaves, Sandra; Tenreiro, Rogério

    2010-01-01

    Microorganisms are ubiquitous in all habitats and are recognized by their metabolic versatility and ability to produce many bioactive compounds, including toxins. Some of the most common toxins present in water are produced by several cyanobacterial species. As a result, their blooms create major threats to animal and human health, tourism, recreation and aquaculture. Quite a few cyanobacterial toxins have been described, including hepatotoxins, neurotoxins, cytotoxins and dermatotoxins. These toxins are secondary metabolites, presenting a vast diversity of structures and variants. Most of cyanobacterial secondary metabolites are peptides or have peptidic substructures and are assumed to be synthesized by non-ribosomal peptide synthesis (NRPS), involving peptide synthetases, or NRPS/PKS, involving peptide synthetases and polyketide synthases hybrid pathways. Besides cyanobacteria, other bacteria associated with aquatic environments are recognized as significant toxin producers, representing important issues in food safety, public health, and human and animal well being. Vibrio species are one of the most representative groups of aquatic toxin producers, commonly associated with seafood-born infections. Some enterotoxins and hemolysins have been identified as fundamental for V. cholerae and V. vulnificus pathogenesis, but there is evidence for the existence of other potential toxins. Campylobacter spp. and Escherichia coli are also water contaminants and are able to produce important toxins after infecting their hosts. Other bacteria associated with aquatic environments are emerging as toxin producers, namely Legionella pneumophila and Aeromonas hydrophila, described as responsible for the synthesis of several exotoxins, enterotoxins and cytotoxins. Furthermore, several Clostridium species can produce potent neurotoxins. Although not considered aquatic microorganisms, they are ubiquitous in the environment and can easily contaminate drinking and irrigation water

  14. The effect of cyanobacterial biomass enrichment by centrifugation and GF/C filtration on subsequent microcystin measurement.

    PubMed

    Rogers, Shelley; Puddick, Jonathan; Wood, Susanna A; Dietrich, Daniel R; Hamilton, David P; Prinsep, Michele R

    2015-03-10

    Microcystins are cyclic peptides produced by multiple cyanobacterial genera. After accumulation in the liver of animals they inhibit eukaryotic serine/threonine protein phosphatases, causing liver disease or death. Accurate detection/quantification of microcystins is essential to ensure safe water resources and to enable research on this toxin. Previous methodological comparisons have focused on detection and extraction techniques, but have not investigated the commonly used biomass enrichment steps. These enrichment steps could modulate toxin production as recent studies have demonstrated that high cyanobacterial cell densities cause increased microcystin levels. In this study, three microcystin-producing strains were processed using no cell enrichment steps (by direct freezing at three temperatures) and with biomass enrichment (by centrifugation or GF/C filtration). After extraction, microcystins were analyzed using liquid chromatography-tandem mass spectrometry. All processing methods tested, except GF/C filtration, resulted in comparable microcystin quotas for all strains. The low yields observed for the filtration samples were caused by adsorption of arginine-containing microcystins to the GF/C filters. Whilst biomass enrichment did not affect microcystin metabolism over the time-frame of normal sample processing, problems associated with GF/C filtration were identified. The most widely applicable processing method was direct freezing of samples as it could be utilized in both field and laboratory environments.

  15. Degradation of cyanobacterial biosignatures by ionizing radiation.

    PubMed

    Dartnell, Lewis R; Storrie-Lombardi, Michael C; Mullineaux, Conrad W; Ruban, Alexander V; Wright, Gary; Griffiths, Andrew D; Muller, Jan-Peter; Ward, John M

    2011-12-01

    Primitive photosynthetic microorganisms, either dormant or dead, may remain today on the martian surface, akin to terrestrial cyanobacteria surviving endolithically in martian analog sites on Earth such as the Antarctic Dry Valleys and the Atacama Desert. Potential markers of martian photoautotrophs include the red edge of chlorophyll reflectance spectra or fluorescence emission from systems of light-harvesting pigments. Such biosignatures, however, would be modified and degraded by long-term exposure to ionizing radiation from the unshielded cosmic ray flux onto the martian surface. In this initial study into this issue, three analytical techniques--absorbance, reflectance, and fluorescence spectroscopy--were employed to determine the progression of the radiolytic destruction of cyanobacteria. The pattern of signal loss for chlorophyll reflection and fluorescence from several biomolecules is characterized and quantified after increasing exposures to ionizing gamma radiation. This allows estimation of the degradation rates of cyanobacterial biosignatures on the martian surface and the identification of promising detectable fluorescent break-down products.

  16. Eutrophication and Warming Boost Cyanobacterial Biomass and Microcystins

    PubMed Central

    Lürling, Miquel; van Oosterhout, Frank; Faassen, Elisabeth

    2017-01-01

    Eutrophication and warming are key drivers of cyanobacterial blooms, but their combined effects on microcystin (MC) concentrations are less studied. We tested the hypothesis that warming promotes cyanobacterial abundance in a natural plankton community and that eutrophication enhances cyanobacterial biomass and MC concentrations. We incubated natural seston from a eutrophic pond under normal, high, and extreme temperatures (i.e., 20, 25, and 30 °C) with and without additional nutrients added (eutrophication) mimicking a pulse as could be expected from projected summer storms under climate change. Eutrophication increased algal- and cyanobacterial biomass by 26 and 8 times, respectively, and led to 24 times higher MC concentrations. This effect was augmented with higher temperatures leading to 45 times higher MC concentrations at 25 °C, with 11 times more cyanobacterial chlorophyll-a and 25 times more eukaryote algal chlorophyll-a. At 30 °C, MC concentrations were 42 times higher, with cyanobacterial chlorophyll-a being 17 times and eukaryote algal chlorophyll-a being 24 times higher. In contrast, warming alone did not yield more cyanobacteria or MCs, because the in situ community had already depleted the available nutrient pool. MC per potential MC producing cell declined at higher temperatures under nutrient enrichments, which was confirmed by a controlled experiment with two laboratory strains of Microcystis aeruginosa. Nevertheless, MC concentrations were much higher at the increased temperature and nutrient treatment than under warming alone due to strongly promoted biomass, lifting N-imitation and promotion of potential MC producers like Microcystis. This study exemplifies the vulnerability of eutrophic urban waters to predicted future summer climate change effects that might aggravate cyanobacterial nuisance. PMID:28208670

  17. Molecular Diffusion through Cyanobacterial Septal Junctions

    PubMed Central

    Nieves-Morión, Mercedes

    2017-01-01

    ABSTRACT Heterocyst-forming cyanobacteria grow as filaments in which intercellular molecular exchange takes place. During the differentiation of N2-fixing heterocysts, regulators are transferred between cells. In the diazotrophic filament, vegetative cells that fix CO2 through oxygenic photosynthesis provide the heterocysts with reduced carbon and heterocysts provide the vegetative cells with fixed nitrogen. Intercellular molecular transfer has been traced with fluorescent markers, including calcein, 5-carboxyfluorescein, and the sucrose analogue esculin, which are observed to move down their concentration gradient. In this work, we used fluorescence recovery after photobleaching (FRAP) assays in the model heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120 to measure the temperature dependence of intercellular transfer of fluorescent markers. We find that the transfer rate constants are directly proportional to the absolute temperature. This indicates that the “septal junctions” (formerly known as “microplasmodesmata”) linking the cells in the filament allow molecular exchange by simple diffusion, without any activated intermediate state. This constitutes a novel mechanism for molecular transfer across the bacterial cytoplasmic membrane, in addition to previously characterized mechanisms for active transport and facilitated diffusion. Cyanobacterial septal junctions are functionally analogous to the gap junctions of metazoans. PMID:28049144

  18. Molecular Diffusion through Cyanobacterial Septal Junctions.

    PubMed

    Nieves-Morión, Mercedes; Mullineaux, Conrad W; Flores, Enrique

    2017-01-03

    Heterocyst-forming cyanobacteria grow as filaments in which intercellular molecular exchange takes place. During the differentiation of N2-fixing heterocysts, regulators are transferred between cells. In the diazotrophic filament, vegetative cells that fix CO2 through oxygenic photosynthesis provide the heterocysts with reduced carbon and heterocysts provide the vegetative cells with fixed nitrogen. Intercellular molecular transfer has been traced with fluorescent markers, including calcein, 5-carboxyfluorescein, and the sucrose analogue esculin, which are observed to move down their concentration gradient. In this work, we used fluorescence recovery after photobleaching (FRAP) assays in the model heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120 to measure the temperature dependence of intercellular transfer of fluorescent markers. We find that the transfer rate constants are directly proportional to the absolute temperature. This indicates that the "septal junctions" (formerly known as "microplasmodesmata") linking the cells in the filament allow molecular exchange by simple diffusion, without any activated intermediate state. This constitutes a novel mechanism for molecular transfer across the bacterial cytoplasmic membrane, in addition to previously characterized mechanisms for active transport and facilitated diffusion. Cyanobacterial septal junctions are functionally analogous to the gap junctions of metazoans.

  19. A Review of Cyanobacterial Odorous and Bioactive Metabolites: Impacts and Management Alternatives in Aquaculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An increased demand has pushed extensive aquaculture towards intensively operated production systems, commonly resulting in eutrophic conditions and cyanobacterial blooms. This review summarizes cyanobacterial secondary metabolites that can cause undesirable tastes and odors (odorous metabolites) o...

  20. Rehabilitating the cyanobacteria - niche partitioning, resource use efficiency and phytoplankton community structure during diazotrophic cyanobacterial blooms.

    PubMed

    Olli, Kalle; Klais, Riina; Tamminen, Timo

    2015-09-01

    Blooms of nitrogen-fixing cyanobacteria are recurrent phenomena in marine and freshwater habitats, and their supplying role in aquatic biogeochemical cycles is generally considered vital. The objective of this study was to analyse whether an increasing proportion of nitrogen-fixing cyanobacteria affects (i) the composition of the non-diazotrophic component of ambient phytoplankton communities and (ii) resource use efficiency (RUE; ratio of Chl a to total nutrients) - an important ecosystem function. We hypothesize that diazotrophs increase community P use and decrease N use efficiencies, as new N is brought into the system, relaxing N, and concomitantly aggravating P limitation. We test this by analysing an extensive data set from the Baltic Sea (> 3700 quantitative phytoplankton samples), known to harbour conspicuous and recurrent blooms of Nodularia spumigena and Aphanizomenon sp.System-level phosphorus use efficiency (RUEP) was positively related to high proportion of diazotrophic cyanobacteria, suggesting aggravation of phosphorus limitation. However, concomitant decrease of nitrogen use efficiency (RUEN) was not observed. Nodularia spumigena, a dominant diazotroph and a notorious toxin producer, had a significantly stronger relationship with RUEP, compared to the competing non-toxic Aphanizomenon sp., confirming niche differentiation in P acquisition strategies between the major bloom-forming cyanobacterial species in the Baltic Sea. Nodularia occurrences were associated with stronger temperature stratification in more offshore environments, indicating higher reliance on in situ P regeneration.By using constrained and unconstrained ordination, permutational multivariate analysis of variance and local similarity analysis, we show that diazotrophic cyanobacteria explained no more than a few percentage of the ambient phytoplankton community variation. The analyses furthermore yielded rather evenly distributed negative and positive effects on individual co

  1. *CYANOBACTERIA AND THEIR TOXINS

    EPA Science Inventory

    Cyanobacteria, or blue-green algae, are naturally-occurring contaminants of surface waters worldwide. These photosynthesizing prokaryotes thrive in warm, shallow, nutrient-rich waters. Many produce potent toxins as secondary metabolites. Cyanobacteria toxins have been document...

  2. Detection of Protein Toxins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have focused on ricin, shiga-like toxin, botulinum neurotoxin (BoNT), and staphylococcal enterotoxin A (SEA), developing sensitive test methods for toxins and marker compounds in food matrices. Although animal models provide the best means for risk assessment, especially for crude toxins in compl...

  3. Lifestyle Evolution in Cyanobacterial Symbionts of Sponges

    SciTech Connect

    Burgsdorf, Ilia; Slaby, Beate M.; Handley, Kim M.; Haber, Markus; Blom, Jochen; Marshall, Christopher W.; Gilbert, Jack A.; Hentschel, Ute; Steindler, Laura

    2015-06-02

    The “Candidatus Synechococcus spongiarum” group includes different clades of cyanobacteria with high 16S rRNA sequence identity (~99%) and is the most abundant and widespread cyanobacterial symbiont of marine sponges. The first draft genome of a “Ca. Synechococcus spongiarum” group member was recently published, providing evidence of genome reduction by loss of genes involved in several nonessential functions. However, “Ca. Synechococcus spongiarum” includes a variety of clades that may differ widely in genomic repertoire and consequently in physiology and symbiotic function. Here, we present three additional draft genomes of “Ca. Synechococcus spongiarum,” each from a different clade. By comparing all four symbiont genomes to those of free-living cyanobacteria, we revealed general adaptations to life inside sponges and specific adaptations of each phylotype. Symbiont genomes shared about half of their total number of coding genes. Common traits of “Ca. Synechococcus spongiarum” members were a high abundance of DNA modification and recombination genes and a reduction in genes involved in inorganic ion transport and metabolism, cell wall biogenesis, and signal transduction mechanisms. Moreover, these symbionts were characterized by a reduced number of antioxidant enzymes and low-weight peptides of photosystem II compared to their free-living relatives. Variability within the “Ca. Synechococcus spongiarum” group was mostly related to immune system features, potential for siderophore-mediated iron transport, and dependency on methionine from external sources. The common absence of genes involved in synthesis of residues, typical of the O antigen of free-living Synechococcus species, suggests a novel mechanism utilized by these symbionts to avoid sponge predation and phage attack.

  4. Lifestyle Evolution in Cyanobacterial Symbionts of Sponges

    PubMed Central

    Burgsdorf, Ilia; Slaby, Beate M.; Handley, Kim M.; Haber, Markus; Blom, Jochen; Marshall, Christopher W.; Gilbert, Jack A.; Hentschel, Ute

    2015-01-01

    ABSTRACT The “Candidatus Synechococcus spongiarum” group includes different clades of cyanobacteria with high 16S rRNA sequence identity (~99%) and is the most abundant and widespread cyanobacterial symbiont of marine sponges. The first draft genome of a “Ca. Synechococcus spongiarum” group member was recently published, providing evidence of genome reduction by loss of genes involved in several nonessential functions. However, “Ca. Synechococcus spongiarum” includes a variety of clades that may differ widely in genomic repertoire and consequently in physiology and symbiotic function. Here, we present three additional draft genomes of “Ca. Synechococcus spongiarum,” each from a different clade. By comparing all four symbiont genomes to those of free-living cyanobacteria, we revealed general adaptations to life inside sponges and specific adaptations of each phylotype. Symbiont genomes shared about half of their total number of coding genes. Common traits of “Ca. Synechococcus spongiarum” members were a high abundance of DNA modification and recombination genes and a reduction in genes involved in inorganic ion transport and metabolism, cell wall biogenesis, and signal transduction mechanisms. Moreover, these symbionts were characterized by a reduced number of antioxidant enzymes and low-weight peptides of photosystem II compared to their free-living relatives. Variability within the “Ca. Synechococcus spongiarum” group was mostly related to immune system features, potential for siderophore-mediated iron transport, and dependency on methionine from external sources. The common absence of genes involved in synthesis of residues, typical of the O antigen of free-living Synechococcus species, suggests a novel mechanism utilized by these symbionts to avoid sponge predation and phage attack. PMID:26037118

  5. Lifestyle Evolution in Cyanobacterial Symbionts of Sponges

    DOE PAGES

    Burgsdorf, Ilia; Slaby, Beate M.; Handley, Kim M.; ...

    2015-06-02

    The “Candidatus Synechococcus spongiarum” group includes different clades of cyanobacteria with high 16S rRNA sequence identity (~99%) and is the most abundant and widespread cyanobacterial symbiont of marine sponges. The first draft genome of a “Ca. Synechococcus spongiarum” group member was recently published, providing evidence of genome reduction by loss of genes involved in several nonessential functions. However, “Ca. Synechococcus spongiarum” includes a variety of clades that may differ widely in genomic repertoire and consequently in physiology and symbiotic function. Here, we present three additional draft genomes of “Ca. Synechococcus spongiarum,” each from a different clade. By comparing all fourmore » symbiont genomes to those of free-living cyanobacteria, we revealed general adaptations to life inside sponges and specific adaptations of each phylotype. Symbiont genomes shared about half of their total number of coding genes. Common traits of “Ca. Synechococcus spongiarum” members were a high abundance of DNA modification and recombination genes and a reduction in genes involved in inorganic ion transport and metabolism, cell wall biogenesis, and signal transduction mechanisms. Moreover, these symbionts were characterized by a reduced number of antioxidant enzymes and low-weight peptides of photosystem II compared to their free-living relatives. Variability within the “Ca. Synechococcus spongiarum” group was mostly related to immune system features, potential for siderophore-mediated iron transport, and dependency on methionine from external sources. The common absence of genes involved in synthesis of residues, typical of the O antigen of free-living Synechococcus species, suggests a novel mechanism utilized by these symbionts to avoid sponge predation and phage attack.« less

  6. Cyanobacterial Polyhydroxybutyrate (PHB): Screening, Optimization and Characterization.

    PubMed

    Ansari, Sabbir; Fatma, Tasneem

    2016-01-01

    In modern life petroleum-based plastic has become indispensable due to its frequent use as an easily available and a low cost packaging and moulding material. However, its rapidly growing use is causing aquatic and terrestrial pollution. Under these circumstances, research and development for biodegradable plastic (bioplastics) is inevitable. Polyhydroxybutyrate (PHB), a type of microbial polyester that accumulates as a carbon/energy storage material in various microorganisms can be a good alternative. In this study, 23 cyanobacterial strains (15 heterocystous and 8 non-heterocystous) were screened for PHB production. The highest PHB (6.44% w/w of dry cells) was detected in Nostoc muscorum NCCU- 442 and the lowest in Spirulina platensis NCCU-S5 (0.51% w/w of dry cells), whereas no PHB was found in Cylindrospermum sp., Oscillatoria sp. and Plectonema sp. Presence of PHB granules in Nostoc muscorum NCCU- 442 was confirmed microscopically with Sudan black B and Nile red A staining. Pretreatment of biomass with methanol: acetone: water: dimethylformamide [40: 40: 18: 2 (MAD-I)] with 2 h magnetic bar stirring followed by 30 h continuous chloroform soxhlet extraction acted as optimal extraction conditions. Optimized physicochemical conditions viz. 7.5 pH, 30°C temperature, 10:14 h light:dark periods with 0.4% glucose (as additional carbon source), 1.0 gl-1 sodium chloride and phosphorus deficiency yielded 26.37% PHB on 7th day instead of 21st day. Using FTIR, 1H NMR and GC-MS, extracted polymer was identified as PHB. Thermal properties (melting temperature, decomposition temperatures etc.) of the extracted polymer were determined by TGA and DSC. Further, the polymer showed good tensile strength and young's modulus with a low extension to break ratio comparable to petrochemical plastic. Biodegradability potential tested as weight loss percentage showed efficient degradation (24.58%) of PHB within 60 days by mixed microbial culture in comparison to petrochemical plastic.

  7. Comparing Band Ratio, Semi-Empirical, and Modified Gaussian Models in Predicting Cyanobacterial Pigments in Eutrophic Inland Waters

    NASA Astrophysics Data System (ADS)

    Robertson, A. L.; Lin, L.; Tedesco, L.; Wilson, J.; Soyeux, E.

    2008-12-01

    Cyanobacteria are known to produce toxins harmful to humans and compounds that alter the taste/odor of water. Monitoring cyanobacteria is of interest to surface water managers because eutrophication of these surface water bodies are common thus increasing the chances of cyanobacterial blooms. Traditionally cyanobacteria are remotely sensed using the spectral properties of the two pigments: chlorophyll a (Chl-a), indicative of all algal and cyanobacteria species, and phycocyanin (PC), specific to cyanobacteria in most freshwater systems. Initial algorithms identifying cyanobacterial pigments used ratios of reflectance at specific wavelengths. In an effort to increase transferability between different systems researchers have included optical properties of water and water constituents to build semi-empirical models. Recently researchers have applied a curve-fitting, modified Gaussian model (MGM), to predict these cyanobacterial pigments. To determine the best performing algorithm this study compares the performance of 4 band ratio, 4 semi-empirical, and 2 modified Gaussian models in predicting PC and Chl-a on three central Indiana reservoirs (Eagle Creek, Geist, Morse). For each of these reservoirs, spectral data were collected with three different sensors (boat-based: ASD Fieldspec, Ocean Optics USB4000; Ariel: AISA Eagle) over a three year period (2005-2007), and water samples concomitant with these spectra were analyzed for concentration of the two pigments and other water constituents. Comparison shows that a model using the MGM strength at 620 nm from a 2005 Morse Reservoir ASD Fieldspec data set shows that the MGM has the best transferability to a 2006 Morse Reservoir ASD Fieldspec data set in predicting phycocyanin (R2 = 0.77; RMSE= 52.45 ppb), and a band ratio model published by Mittenzwey et al. 1991 has the best transferability in predicting chlorophyll a (R2 = 0.74; RMSE 16.31=ppb).

  8. Cyanobacterial extracts containing microcystins affect the growth, nodulation process and nitrogen uptake of faba bean (Vicia faba L., Fabaceae).

    PubMed

    Lahrouni, Majida; Oufdou, Khalid; Faghire, Mustapha; Peix, Alvaro; El Khalloufi, Fatima; Vasconcelos, Vitor; Oudra, Brahim

    2012-04-01

    The use of irrigation water containing cyanobacterial toxins may generate a negative impact in both yield and quality of agricultural crops causing significant economic losses. We evaluated the effects of microcystins (MC) on the growth, nodulation process and nitrogen uptake of a Faba bean cultivar (Vicia faba L., Fabaceae), particularly the effect of MC on rhizobia-V. faba symbiosis. Three rhizobial strains (RhOF4, RhOF6 and RhOF21), isolated from nodules of local V. faba were tested. The exposure of rhizobia to MC showed that the toxins had a negative effect on the rhizobial growth especially at the highest concentrations of 50 and 100 μg/l. The germination of faba bean seeds was also affected by cyanotoxins. We registered germination rates of 75 and 68.75% at the toxin levels of 50 and 100 μg/l as compared to the control (100%). The obtained results also showed there was a negative effect of MC on plants shoot, root (dry weight) and total number of nodules per plant. Cyanotoxins exposure induced a significant effect on nitrogen assimilation by faba bean seedlings inoculated with selected rhizobial strains RhOF6 and RhOF21, while the effect was not significant on beans seedling inoculated with RhOF4. This behavior of tolerant rhizobia-legumes symbioses may constitute a very important pathway to increase soil fertility and quality and can represent a friendly biotechnological way to remediate cyanotoxins contamination in agriculture.

  9. Cyanobacterial bloom management through integrated monitoring and forecasting in large shallow eutrophic Lake Taihu (China).

    PubMed

    Qin, Boqiang; Li, Wei; Zhu, Guangwei; Zhang, Yunlin; Wu, Tingfeng; Gao, Guang

    2015-04-28

    The large shallow eutrophic Lake Taihu in China has long suffered from eutrophication and toxic cyanobacterial blooms. Despite considerable efforts to divert effluents from the watershed, the cyanobacterial blooms still reoccur and persist throughout summer. To mitigate cyanobacterial bloom pollution risk, a large scale integrated monitoring and forecasting system was developed, and a series of emergency response measures were instigated based on early warning. This system has been in place for 2009-2012. With this integrated monitoring system, it was found that the detectable maximum and average cyanobacterial bloom area were similar to that before drinking water crisis, indicating that poor eutrophic status and cyanobacterial bloom had persisted without significant alleviation. It also revealed that cyanobacterial bloom would occur after the intense storm, which may be associated with the increase in buoyance of cyanobacterial colonies. Although the cyanobacterial blooms had persisted during the monitoring period, there had been a reduction in frequency and intensity of the cyanobacterial bloom induced black water agglomerates (a phenomenon of algal bloom death decay to release a large amount black dissolved organic matter), and there have been no further drinking water crises. This monitoring and response strategy can reduce the cyanobacterial bloom pollution risk, but cannot reduce eutrophication and cyanobacterial blooms, problems which will take decades to resolve.

  10. Cyanobacterial Polyhydroxybutyrate (PHB): Screening, Optimization and Characterization

    PubMed Central

    Ansari, Sabbir; Fatma, Tasneem

    2016-01-01

    In modern life petroleum-based plastic has become indispensable due to its frequent use as an easily available and a low cost packaging and moulding material. However, its rapidly growing use is causing aquatic and terrestrial pollution. Under these circumstances, research and development for biodegradable plastic (bioplastics) is inevitable. Polyhydroxybutyrate (PHB), a type of microbial polyester that accumulates as a carbon/energy storage material in various microorganisms can be a good alternative. In this study, 23 cyanobacterial strains (15 heterocystous and 8 non-heterocystous) were screened for PHB production. The highest PHB (6.44% w/w of dry cells) was detected in Nostoc muscorum NCCU- 442 and the lowest in Spirulina platensis NCCU-S5 (0.51% w/w of dry cells), whereas no PHB was found in Cylindrospermum sp., Oscillatoria sp. and Plectonema sp. Presence of PHB granules in Nostoc muscorum NCCU- 442 was confirmed microscopically with Sudan black B and Nile red A staining. Pretreatment of biomass with methanol: acetone: water: dimethylformamide [40: 40: 18: 2 (MAD-I)] with 2 h magnetic bar stirring followed by 30 h continuous chloroform soxhlet extraction acted as optimal extraction conditions. Optimized physicochemical conditions viz. 7.5 pH, 30°C temperature, 10:14 h light:dark periods with 0.4% glucose (as additional carbon source), 1.0 gl-1 sodium chloride and phosphorus deficiency yielded 26.37% PHB on 7th day instead of 21st day. Using FTIR, 1H NMR and GC-MS, extracted polymer was identified as PHB. Thermal properties (melting temperature, decomposition temperatures etc.) of the extracted polymer were determined by TGA and DSC. Further, the polymer showed good tensile strength and young’s modulus with a low extension to break ratio comparable to petrochemical plastic. Biodegradability potential tested as weight loss percentage showed efficient degradation (24.58%) of PHB within 60 days by mixed microbial culture in comparison to petrochemical plastic

  11. Exploring cyanobacterial genomes for natural product biosynthesis pathways.

    PubMed

    Micallef, Melinda L; D'Agostino, Paul M; Al-Sinawi, Bakir; Neilan, Brett A; Moffitt, Michelle C

    2015-06-01

    Cyanobacteria produce a vast array of natural products, some of which are toxic to human health, while others possess potential pharmaceutical activities. Genome mining enables the identification and characterisation of natural product gene clusters; however, the current number of cyanobacterial genomes remains low compared to other phyla. There has been a recent effort to rectify this issue by increasing the number of sequenced cyanobacterial genomes. This has enabled the identification of biosynthetic gene clusters for structurally diverse metabolites, including non-ribosomal peptides, polyketides, ribosomal peptides, UV-absorbing compounds, alkaloids, terpenes and fatty acids. While some of the identified biosynthetic gene clusters correlate with known metabolites, genome mining also highlights the number and diversity of clusters for which the product is unknown (referred to as orphan gene clusters). A number of bioinformatic tools have recently been developed in order to predict the products of orphan gene clusters; however, in some cases the complexity of the cyanobacterial pathways makes the prediction problematic. This can be overcome by the use of mass spectrometry-guided natural product genome mining, or heterologous expression. Application of these techniques to cyanobacterial natural product gene clusters will be explored.

  12. Cyanobacterial reuse of extracellular organic carbon in microbial mats

    PubMed Central

    Stuart, Rhona K; Mayali, Xavier; Lee, Jackson Z; Craig Everroad, R; Hwang, Mona; Bebout, Brad M; Weber, Peter K; Pett-Ridge, Jennifer; Thelen, Michael P

    2016-01-01

    Cyanobacterial organic matter excretion is crucial to carbon cycling in many microbial communities, but the nature and bioavailability of this C depend on unknown physiological functions. Cyanobacteria-dominated hypersaline laminated mats are a useful model ecosystem for the study of C flow in complex communities, as they use photosynthesis to sustain a more or less closed system. Although such mats have a large C reservoir in the extracellular polymeric substances (EPSs), the production and degradation of organic carbon is not well defined. To identify extracellular processes in cyanobacterial mats, we examined mats collected from Elkhorn Slough (ES) at Monterey Bay, California, for glycosyl and protein composition of the EPS. We found a prevalence of simple glucose polysaccharides containing either α or β (1,4) linkages, indicating distinct sources of glucose with differing enzymatic accessibility. Using proteomics, we identified cyanobacterial extracellular enzymes, and also detected activities that indicate a capacity for EPS degradation. In a less complex system, we characterized the EPS of a cyanobacterial isolate from ES, ESFC-1, and found the extracellular composition of biofilms produced by this unicyanobacterial culture were similar to that of natural mats. By tracing isotopically labeled EPS into single cells of ESFC-1, we demonstrated rapid incorporation of extracellular-derived carbon. Taken together, these results indicate cyanobacteria reuse excess organic carbon, constituting a dynamic pool of extracellular resources in these mats. PMID:26495994

  13. Detection of various freshwater cyanobacterial toxins using ultra-performance liquid chromatography tandem mass spectrometry.

    PubMed

    Oehrle, Stuart A; Southwell, Ben; Westrick, Judy

    2010-05-01

    Several freshwater cyanobacteria species have the capability to produce toxic compounds, frequently referred to as cyanotoxins. The most prevalent of these cyanotoxins is microcystin LR. Recognizing the potential health risk, France, Italy, Poland, Australia, Canada, and Brazil have set either standards or guidelines for the amount of microcystin LR permissible in drinking water based on the World Health Organization guideline of one microg/L of microcystin LR. Recently, the United States Environmental Protection Agency has begun to evaluate the occurrence and health effects of cyanotoxins and their susceptibility to water treatment under the Safe Drinking Water Act through the Contaminant Candidate List (CCL). A recent update of the Contaminant Candidate List focuses research and data collection on the cyanotoxins microcystin LR, anatoxin-a, and cylindrospermopsin. Liquid Chromatography/Tandem-Mass Spectrometry (LC/MS/MS) is a powerful tool for the analysis of various analytes in a wide variety of matrices because of its sensitivity and selectivity. The use of smaller column media (sub 2 microm particles) was investigated to both improve the speed, sensitivity and resolution, and to quantify the CCL cyanotoxins, in a single analysis, using Ultra-Performance Liquid Chromatography (UPLC) combined with tandem mass spectrometry. Natural waters and spiked samples were analyzed to show proof-of-performance. The presented method was able to clearly resolve each of the cyanotoxins in less than eight minutes with specificity and high spike recoveries.

  14. The Risk of Cyanobacterial Toxins in Dialysate, What do we Know?

    EPA Science Inventory

    Surface waters are increasingly contaminated by cyanobacteria, which may produce potent cyanotoxins harmful to animals and humans. Hemodialysis patients are at high risk of injury from waterborne contaminants in the water used to prepare dialysate. Episodes of acute illness and d...

  15. The Presence of the Cyanobacterial Toxin Microcystin in Black Band Disease of Corals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Black band disease (BBD) of corals consists of a pathogenic consortium of microorganisms of four physiological functional groups: phototrophs, heterotrophs, sulfate reducers, and sulfide oxidizers. Together, using a combination of behavioral and physiological strategies, the members of the BBD con...

  16. Cyanobacterial bloom detection based on coherence between ferrybox observations

    NASA Astrophysics Data System (ADS)

    Groetsch, Philipp M. M.; Simis, Stefan G. H.; Eleveld, Marieke A.; Peters, Steef W. M.

    2014-12-01

    Cyanobacterial bloom detection from flow-through optical sensors on ships-of-opportunity ('ferryboxes') is challenging in periods of strong stratification and due to varying cell physiology and phytoplankton community composition. Wavelet coherence analysis between ferrybox parameters (chlorophyll-a fluorescence, phycocyanin fluorescence, turbidity) was used to delineate blooms in a dataset of ten ferrybox transects, recorded during the 2005 cyanobacterial bloom season in the Baltic Sea. Independent wind speed and sea-surface temperature data were used to classify areas of cyanobacterial dominance as mixed, stratified, or surfacing bloom. These classified subsets of ferrybox observations were compared against remotely sensed chlorophyll-a concentrations, which resulted in a scheme for the interpretation of surface water phytoplankton biomass from multi-source observations. Ferrybox optical signals were significantly coherent from the onset until the end of the cyanobacterial bloom period under both stratified and mixed conditions. This suggests that the coherence analysis is sensitive to high-level community composition. Strongly stratified and suspected surfacing bloom was associated with unrealistically high remotely sensed chlorophyll-a estimates, indicating the need to flag stratified bloom areas when interpreting remote sensing imagery. The ferrybox fluorescence and turbidity signals at the 5-m sampling depth were, paradoxically, low under these conditions, suggesting that direct comparison between remote sensing and flow-through observations is not useful for stratified blooms. Correlations between ferrybox measurements and remotely sensed observations improved consistently when stratified or surfacing cyanobacterial bloom was excluded from the regression. It is discussed how coherence analysis of ferrybox observations can aid the interpretation of remotely sensed data in situations where meteorological observations suggest incomplete vertical mixing.

  17. [Intoxication of botulinum toxin].

    PubMed

    Chudzicka, Aleksandra

    2015-09-01

    Botulinum toxin is an egzotoxin produced by Gram positive bacteria Clostridium botulinum. It is among the most potent toxins known. The 3 main clinical presentations of botulism are as follows: foodborne botulism, infant botulism and wound botulism. The main symptom of intoxication is flat muscles paralysis. The treatment is supportive care and administration of antitoxin. In prevention the correct preparing of canned food is most important. Botulinum toxin is accepted as a biological weapon.

  18. The Cyanobacterial Role in the Resistance of Feather Mosses to Decomposition—Toward a New Hypothesis

    PubMed Central

    Rousk, Kathrin; DeLuca, Thomas H.; Rousk, Johannes

    2013-01-01

    Cyanobacteria-plant symbioses play an important role in many ecosystems due to the fixation of atmospheric nitrogen (N) by the cyanobacterial symbiont. The ubiquitous feather moss Pleurozium schreberi (Brid.) Mitt. is colonized by cyanobacteria in boreal systems with low N deposition. Here, cyanobacteria fix substantial amounts of N2 and represent a potential N source. The feather moss appears to be resistant to decomposition, which could be partly a result of toxins produced by cyanobacteria. To assess how cyanobacteria modulated the toxicity of moss, we measured inhibition of bacterial growth. Moss with varying numbers of cyanobacteria was added to soil bacteria to test the inhibition of their growth using the thymidine incorporation technique. Moss could universally inhibit bacterial growth, but moss toxicity did not increase with N2 fixation rates (numbers of cyanobacteria). Instead, we see evidence for a negative relationship between moss toxicity to bacteria and N2 fixation, which could be related to the ecological mechanisms that govern the cyanobacteria – moss relationship. We conclude that cyanobacteria associated with moss do not contribute to the resistance to decomposition of moss, and from our results emerges the question as to what type of relationship the moss and cyanobacteria share. PMID:23614013

  19. Electrochemical immunoassay using quantum dot/antibody probe for identification of cyanobacterial hepatotoxin microcystin-LR.

    PubMed

    Yu, Hye-Weon; Lee, Jinwook; Kim, Sungyoun; Nguyen, Giang Huong; Kim, In S

    2009-08-01

    The presence of cyanobacterial hepatotoxins such as microcystin-LR poses health threats to humans due to their potential for causing severe physiological effects when contaminated drinking water is ingested. Here, the electrochemical detection of microcystin-LR is explored using a quantum dot/antibody (QD/Ab) probe for nanoparticle-based amplification and direct electrochemical transduction. The immunological recognition of microcystin-LR using the QD/Ab probe was amplified and converted to an electrochemical signal by measuring the cadmium ions released from QD based on square wave stripping voltammetry under optimized electrochemical factors. Whereas a qualitative analysis for microcystin-LR was achieved using the specific peak potential of the anodic voltammogram at -0.6 +/- 0.05 V, concentration of the toxin was quantified based on the charge density of the anodic peak; a dynamic range of 0.227 to 50 microg/L and limit of detection of 0.099 microg/L were obtained with high sensitivity. The extracted microcystin-LR from Microcystis aeruginosa was estimated as 1,944 microg/g of dried weight of the microorganism.

  20. Chorea caused by toxins.

    PubMed

    Miyasaki, Janis M

    2011-01-01

    Chorea is uncommonly caused by toxins. Anecdotal evidence from cases of toxin-induced chorea assists in our understanding of neurodegenerative diseases associated with chorea. Beginning in medieval Europe with ergotism and the "fire that twisted people," spanning to crack dancing in contemporary times and the coexistence of alcohol abuse with chorea, toxins may exert direct effects to enhance mesolimbic dopamine transmission or indirect effects through gamma-aminobutyric acid modulation. The following chapter will discuss toxins associated with chorea and the presumed pathophysiology underlying the movement disorders in these case series.

  1. Botulinum toxin injection - larynx

    MedlinePlus

    Injection laryngoplasty; Botox-larynx: spasmodic dysphonia-BTX; Essential voice tremor (EVT)-btx; Glottic insufficiency; Percutaneous electromyography-guided botulinum toxin treatment; Percutaneous indirect laryngoscopy- ...

  2. BMAA--an unusual cyanobacterial neurotoxin.

    PubMed

    Vyas, Kaivalya J; Weiss, John H

    2009-01-01

    Abstract The toxin ss-N-methylamino-L-alanine (BMAA) was proposed to contribute to the ALS/Parkinsonism-dementia complex of Guam (ALS/PDC) based on its presence in cycad seeds, which constituted a dietary item in afflicted populations, and its ability to induce a similar disease phenotype in primates. Although the role of BMAA in human neurodegenerative disease is still highly debated, it appears to injure cultured neurons via mechanisms involving overactivation of neuroexcitatory glutamate receptors. However, BMAA lacks the side-chain acidic group of glutamate and other excitatory amino acids, and in its place has an amino group. In past studies we found that toxic and excitatory effects of BMAA on cultured neurons were dependent upon the presence of bicarbonate in the medium, and suggested that formation of a carbamate adduct of the side-chain amino group might produce structures capable of activating glutamate receptors. Also, while BMAA is a weal agonist at NMDA-type glutamate receptors, we found low levels of BMAA to selectively damage vulnerable sub-populations of neurons, including motor neurons, via activation of AMPA/kainate receptors. Recent reports that BMAA is produced by cyanobacteria in diverse ecosystems and is present in brain and spinal cord tissues from sporadic ALS and Alzheimer's patients as well as brains of ALS/PDC patients provide strong motivation for further investigations of its toxic mechanisms and contributions to human disease.

  3. Defense against toxin weapons

    SciTech Connect

    Franz, D.R.

    1994-01-01

    The purpose of this manual is to provide basic information on biological toxins to military leaders and health-care providers at all levels to help them make informed decisions on protecting their troops from toxins. Much of the information contained herein will also be of interest to individuals charged with countering domestic and international terrorism. We typically fear what we do not understand.

  4. Fenced cultivation of water hyacinth for cyanobacterial bloom control.

    PubMed

    Qin, Hongjie; Zhang, Zhiyong; Liu, Haiqin; Li, Dunhai; Wen, Xuezheng; Zhang, Yingying; Wang, Yan; Yan, Shaohua

    2016-09-01

    To achieve the goals of harmful cyanobacterial bloom control and nutrient removal, an eco-engineering project with water hyacinth planted in large-scale enclosures was conducted based on meteorological and hydrographical conditions in Lake Dianchi. Water quality, cyanobacteria distribution, and nutrient (TN, TP) bioaccumulation were investigated. Elevated concentrations of N and P and low Secchi depth (SD) were relevant to large amount of cyanobacteria trapped in regions with water hyacinth, where biomass of the dominant cyanobacteria Microcystis (4.95 × 10(10) cells L(-1)) was more than 30-fold compared with values of the control. A dramatic increase of TN and TP contents in the plants was found throughout the sampling period. Results from the present study confirmed the great potential to use water hyacinth for cyanobacterial bloom control and nutrient removal in algal lakes such as Lake Dianchi.

  5. Integrating mass spectrometry and genomics for cyanobacterial metabolite discovery.

    PubMed

    Moss, Nathan A; Bertin, Matthew J; Kleigrewe, Karin; Leão, Tiago F; Gerwick, Lena; Gerwick, William H

    2016-03-01

    Filamentous marine cyanobacteria produce bioactive natural products with both potential therapeutic value and capacity to be harmful to human health. Genome sequencing has revealed that cyanobacteria have the capacity to produce many more secondary metabolites than have been characterized. The biosynthetic pathways that encode cyanobacterial natural products are mostly uncharacterized, and lack of cyanobacterial genetic tools has largely prevented their heterologous expression. Hence, a combination of cutting edge and traditional techniques has been required to elucidate their secondary metabolite biosynthetic pathways. Here, we review the discovery and refined biochemical understanding of the olefin synthase and fatty acid ACP reductase/aldehyde deformylating oxygenase pathways to hydrocarbons, and the curacin A, jamaicamide A, lyngbyabellin, columbamide, and a trans-acyltransferase macrolactone pathway encoding phormidolide. We integrate into this discussion the use of genomics, mass spectrometric networking, biochemical characterization, and isolation and structure elucidation techniques.

  6. Integrating mass spectrometry and genomics for cyanobacterial metabolite discovery

    PubMed Central

    Bertin, Matthew J.; Kleigrewe, Karin; Leão, Tiago F.; Gerwick, Lena

    2016-01-01

    Filamentous marine cyanobacteria produce bioactive natural products with both potential therapeutic value and capacity to be harmful to human health. Genome sequencing has revealed that cyanobacteria have the capacity to produce many more secondary metabolites than have been characterized. The biosynthetic pathways that encode cyanobacterial natural products are mostly uncharacterized, and lack of cyanobacterial genetic tools has largely prevented their heterologous expression. Hence, a combination of cutting edge and traditional techniques has been required to elucidate their secondary metabolite biosynthetic pathways. Here, we review the discovery and refined biochemical understanding of the olefin synthase and fatty acid ACP reductase/aldehyde deformylating oxygenase pathways to hydrocarbons, and the curacin A, jamaicamide A, lyngbyabellin, columbamide, and a trans-acyltransferase macrolactone pathway encoding phormidolide. We integrate into this discussion the use of genomics, mass spectrometric networking, biochemical characterization, and isolation and structure elucidation techniques. PMID:26578313

  7. Protection against Shiga Toxins

    PubMed Central

    Kavaliauskiene, Simona; Dyve Lingelem, Anne Berit; Skotland, Tore; Sandvig, Kirsten

    2017-01-01

    Shiga toxins consist of an A-moiety and five B-moieties able to bind the neutral glycosphingolipid globotriaosylceramide (Gb3) on the cell surface. To intoxicate cells efficiently, the toxin A-moiety has to be cleaved by furin and transported retrogradely to the Golgi apparatus and to the endoplasmic reticulum. The enzymatically active part of the A-moiety is then translocated to the cytosol, where it inhibits protein synthesis and in some cell types induces apoptosis. Protection of cells can be provided either by inhibiting binding of the toxin to cells or by interfering with any of the subsequent steps required for its toxic effect. In this article we provide a brief overview of the interaction of Shiga toxins with cells, describe some compounds and conditions found to protect cells against Shiga toxins, and discuss whether they might also provide protection in animals and humans. PMID:28165371

  8. The cyanobacterial hepatotoxin microcystin binds to proteins and increases the fitness of microcystis under oxidative stress conditions.

    PubMed

    Zilliges, Yvonne; Kehr, Jan-Christoph; Meissner, Sven; Ishida, Keishi; Mikkat, Stefan; Hagemann, Martin; Kaplan, Aaron; Börner, Thomas; Dittmann, Elke

    2011-03-18

    Microcystins are cyanobacterial toxins that represent a serious threat to drinking water and recreational lakes worldwide. Here, we show that microcystin fulfils an important function within cells of its natural producer Microcystis. The microcystin deficient mutant ΔmcyB showed significant changes in the accumulation of proteins, including several enzymes of the Calvin cycle, phycobiliproteins and two NADPH-dependent reductases. We have discovered that microcystin binds to a number of these proteins in vivo and that the binding is strongly enhanced under high light and oxidative stress conditions. The nature of this binding was studied using extracts of a microcystin-deficient mutant in vitro. The data obtained provided clear evidence for a covalent interaction of the toxin with cysteine residues of proteins. A detailed investigation of one of the binding partners, the large subunit of RubisCO showed a lower susceptibility to proteases in the presence of microcystin in the wild type. Finally, the mutant defective in microcystin production exhibited a clearly increased sensitivity under high light conditions and after hydrogen peroxide treatment. Taken together, our data suggest a protein-modulating role for microcystin within the producing cell, which represents a new addition to the catalogue of functions that have been discussed for microbial secondary metabolites.

  9. Microsensor measurements of hydrogen gas dynamics in cyanobacterial microbial mats.

    PubMed

    Nielsen, Michael; Revsbech, Niels P; Kühl, Michael

    2015-01-01

    We used a novel amperometric microsensor for measuring hydrogen gas production and consumption at high spatio-temporal resolution in cyanobacterial biofilms and mats dominated by non-heterocystous filamentous cyanobacteria (Microcoleus chtonoplastes and Oscillatoria sp.). The new microsensor is based on the use of an organic electrolyte and a stable internal reference system and can be equipped with a chemical sulfide trap in the measuring tip; it exhibits very stable and sulfide-insensitive measuring signals and a high sensitivity (1.5-5 pA per μmol L(-1) H2). Hydrogen gas measurements were done in combination with microsensor measurements of scalar irradiance, O2, pH, and H2S and showed a pronounced H2 accumulation (of up to 8-10% H2 saturation) within the upper mm of cyanobacterial mats after onset of darkness and O2 depletion. The peak concentration of H2 increased with the irradiance level prior to darkening. After an initial build-up over the first 1-2 h in darkness, H2 was depleted over several hours due to efflux to the overlaying water, and due to biogeochemical processes in the uppermost oxic layers and the anoxic layers of the mats. Depletion could be prevented by addition of molybdate pointing to sulfate reduction as a major sink for H2. Immediately after onset of illumination, a short burst of presumably photo-produced H2 due to direct biophotolysis was observed in the illuminated but anoxic mat layers. As soon as O2 from photosynthesis started to accumulate, the H2 was consumed rapidly and production ceased. Our data give detailed insights into the microscale distribution and dynamics of H2 in cyanobacterial biofilms and mats, and further support that cyanobacterial H2 production can play a significant role in fueling anaerobic processes like e.g., sulfate reduction or anoxygenic photosynthesis in microbial mats.

  10. Microsensor measurements of hydrogen gas dynamics in cyanobacterial microbial mats

    PubMed Central

    Nielsen, Michael; Revsbech, Niels P.; Kühl, Michael

    2015-01-01

    We used a novel amperometric microsensor for measuring hydrogen gas production and consumption at high spatio-temporal resolution in cyanobacterial biofilms and mats dominated by non-heterocystous filamentous cyanobacteria (Microcoleus chtonoplastes and Oscillatoria sp.). The new microsensor is based on the use of an organic electrolyte and a stable internal reference system and can be equipped with a chemical sulfide trap in the measuring tip; it exhibits very stable and sulfide-insensitive measuring signals and a high sensitivity (1.5–5 pA per μmol L-1 H2). Hydrogen gas measurements were done in combination with microsensor measurements of scalar irradiance, O2, pH, and H2S and showed a pronounced H2 accumulation (of up to 8–10% H2 saturation) within the upper mm of cyanobacterial mats after onset of darkness and O2 depletion. The peak concentration of H2 increased with the irradiance level prior to darkening. After an initial build-up over the first 1–2 h in darkness, H2 was depleted over several hours due to efflux to the overlaying water, and due to biogeochemical processes in the uppermost oxic layers and the anoxic layers of the mats. Depletion could be prevented by addition of molybdate pointing to sulfate reduction as a major sink for H2. Immediately after onset of illumination, a short burst of presumably photo-produced H2 due to direct biophotolysis was observed in the illuminated but anoxic mat layers. As soon as O2 from photosynthesis started to accumulate, the H2 was consumed rapidly and production ceased. Our data give detailed insights into the microscale distribution and dynamics of H2 in cyanobacterial biofilms and mats, and further support that cyanobacterial H2 production can play a significant role in fueling anaerobic processes like e.g., sulfate reduction or anoxygenic photosynthesis in microbial mats. PMID:26257714

  11. The Extracellular Matrix in Photosynthetic Mats: A Cyanobacterial Gingerbread House

    NASA Astrophysics Data System (ADS)

    Stuart, R.; Stannard, W.; Bebout, B.; Pett-Ridge, J.; Mayali, X.; Weber, P. K.; Lipton, M. S.; Lee, J.; Everroad, R. C.; Thelen, M.

    2014-12-01

    Hypersaline laminated cyanobacterial mats are excellent model systems for investigating photoautotrophic contributions to biogeochemical cycling on a millimeter scale. These self-sustaining ecosystems are characterized by steep physiochemical gradients that fluctuate dramatically on hour timescales, providing a dynamic environment to study microbial response. However, elucidating the distribution of energy from light absorption into biomass requires a complete understanding of the various constituents of the mat. Extracellular polymeric substances (EPS), which can be composed of proteins, polysaccharides, lipids and DNA are a major component of these mats and may function in the redistribution of nutrients and metabolites within the community. To test this notion, we established a model mat-building culture for comparison with the phylogenetically diverse natural mat communities. In these two systems we determined how proteins and glycans in the matrix changed as a function of light and tracked nutrient flow from the matrix. Using mass spectrometry metaproteomics analysis, we found homologous proteins in both field and culture extracellular matrix that point to cyanobacterial turnover of amino acids, inorganic nutrients, carbohydrates and nucleic acids from the EPS. Other abundant functions identified included oxidative stress response from both the cyanobacteria and heterotrophs and cyanobacterial structural proteins that may play a role in mat cohesion. Several degradative enzymes also varied in abundance in the EPS in response to light availability, suggesting active secretion. To further test cyanobacterial EPS turnover, we generated isotopically-labeled EPS and used NanoSIMS to trace uptake of this labeled EPS. Our findings suggest Cyanobacteria may facilitate nutrient transfer to other groups, as well as uptake of their own products through degradation of EPS components. This work provides evidence for the essential roles of EPS for storage, structural

  12. Occurrence of cyanobacteria and microcystin toxins in raw and treated waters of the Nile River, Egypt: implication for water treatment and human health.

    PubMed

    Mohamed, Zakaria A; Deyab, Mohamed Ali; Abou-Dobara, Mohamed I; El-Sayed, Ahmad K; El-Raghi, Wesam M

    2015-08-01

    Monitoring of cyanobacteria and their associated toxins has intensified in raw water sources of drinking water treatment plants (WTPs) in most countries of the world. However, it is not explored yet for Egyptian WTPs. Therefore, this study was undertaken to investigate the occurrence of cyanobacteria and their microcystin (MC) toxins in the Nile River source water of Damietta WTP during warm months (April-September 2013) and to evaluate the removal efficiency of both cyanobacterial cells and MCs by conventional methods used in this plant as a representative of Egyptian drinking WTPs. The results showed that the source water at the intake of Damietta WTP contained dense cyanobacterial population (1.1-6.6 × 107 cells L(-1)) dominated by Microcystis aeruginosa. This bloom was found to produce MC-RR and MC-LR. Both cyanobacterial cell density and intracellular MCs in the intake source water increased with the increase in temperature and nutrients during the study period, with maximum values obtained in August. During treatment processes, cyanobacterial cells were incompletely removed by coagulation/flocculation/sedimentation (C/F/S; 91-96.8%) or sand filtration (93.3-98.9%). Coagulation/flocculation induced the release of MCs into the ambient water, and the toxins were not completely removed or degraded during further treatment stages (filtration and chlorination). MCs in outflow tank water were detected in high concentrations (1.1-3.6 μg L - 1), exceeding WHO provisional guideline value of 1 μg L - 1 for MC-LR in drinking water. Based on this study, regular monitoring of cyanobacteria and their cyanotoxins in the intake source water and at different stages at all WTPs is necessary to provide safe drinking water to consumers or to prevent exposure of consumers to hazardous cyanobacterial metabolites.

  13. Cyanobacterial Biofuels: Strategies and Developments on Network and Modeling.

    PubMed

    Klanchui, Amornpan; Raethong, Nachon; Prommeenate, Peerada; Vongsangnak, Wanwipa; Meechai, Asawin

    2016-10-26

    Cyanobacteria, the phototrophic microorganisms, have attracted much attention recently as a promising source for environmentally sustainable biofuels production. However, barriers for commercial markets of cyanobacteria-based biofuels concern the economic feasibility. Miscellaneous strategies for improving the production performance of cyanobacteria have thus been developed. Among these, the simple ad hoc strategies resulting in failure to optimize fully cell growth coupled with desired product yield are explored. With the advancement of genomics and systems biology, a new paradigm toward systems metabolic engineering has been recognized. In particular, a genome-scale metabolic network reconstruction and modeling is a crucial systems-based tool for whole-cell-wide investigation and prediction. In this review, the cyanobacterial genome-scale metabolic models, which offer a system-level understanding of cyanobacterial metabolism, are described. The main process of metabolic network reconstruction and modeling of cyanobacteria are summarized. Strategies and developments on genome-scale network and modeling through the systems metabolic engineering approach are advanced and employed for efficient cyanobacterial-based biofuels production.

  14. Revealing the Dynamics of Thylakoid Membranes in Living Cyanobacterial Cells

    DOE PAGES

    Stingaciu, Laura-Roxana; O’Neill, Hugh; Liberton, Michelle; ...

    2016-01-21

    Cyanobacteria are photosynthetic prokaryotes that make major contributions to the production of the oxygen in the Earth atmosphere. The photosynthetic machinery in cyanobacterial cells is housed in flattened membrane structures called thylakoids. The structural organization of cyanobacterial cells and the arrangement of the thylakoid membranes in response to environmental conditions have been widely investigated. However, there is limited knowledge about the internal dynamics of these membranes in terms of their flexibility and motion during the photosynthetic process. We present a direct observation of thylakoid membrane undulatory motion in vivo and show a connection between membrane mobility and photosynthetic activity. High-resolutionmore » inelastic neutron scattering experiments on the cyanobacterium Synechocystis sp. PCC 6803 assessed the flexibility of cyanobacterial thylakoid membrane sheets and the dependence of the membranes on illumination conditions. We observed softer thylakoid membranes in the dark that have three-to four fold excess mobility compared to membranes under high light conditions. We find our analysis indicates that electron transfer between photosynthetic reaction centers and the associated electrochemical proton gradient across the thylakoid membrane result in a significant driving force for excess membrane dynamics. Lastly, these observations provide a deeper understanding of the relationship between photosynthesis and cellular architecture.« less

  15. Revealing the Dynamics of Thylakoid Membranes in Living Cyanobacterial Cells

    SciTech Connect

    Stingaciu, Laura-Roxana; O’Neill, Hugh; Urban, Volker S.; Ohl, Michael

    2016-01-21

    Cyanobacteria are photosynthetic prokaryotes that make major contributions to the production of the oxygen in the Earth atmosphere. The photosynthetic machinery in cyanobacterial cells is housed in flattened membrane structures called thylakoids. The structural organization of cyanobacterial cells and the arrangement of the thylakoid membranes in response to environmental conditions have been widely investigated. However, there is limited knowledge about the internal dynamics of these membranes in terms of their flexibility and motion during the photosynthetic process. We present a direct observation of thylakoid membrane undulatory motion in vivo and show a connection between membrane mobility and photosynthetic activity. High-resolution inelastic neutron scattering experiments on the cyanobacterium Synechocystis sp. PCC 6803 assessed the flexibility of cyanobacterial thylakoid membrane sheets and the dependence of the membranes on illumination conditions. We observed softer thylakoid membranes in the dark that have three-to four fold excess mobility compared to membranes under high light conditions. We find our analysis indicates that electron transfer between photosynthetic reaction centers and the associated electrochemical proton gradient across the thylakoid membrane result in a significant driving force for excess membrane dynamics. Lastly, these observations provide a deeper understanding of the relationship between photosynthesis and cellular architecture.

  16. Global change feed-back inhibits cyanobacterial photosynthesis

    PubMed Central

    Walter Helbling, E.; Banaszak, Anastazia T.; Villafañe, Virginia E.

    2015-01-01

    Cyanobacteria are an important component of aquatic ecosystems, with a proliferation of massive cyanobacterial blooms predicted worldwide under increasing warming conditions. In addition to temperature, other global change related variables, such as water column stratification, increases in dissolved organic matter (DOM) discharge into freshwater systems and greater wind stress (i.e., more opaque and mixed upper water column/epilimnion) might also affect the responses of cyanobacteria. However, the combined effects of these variables on cyanobacterial photosynthesis remain virtually unknown. Here we present evidence that this combination of global-change conditions results in a feed-back mechanism by which, fluctuations in solar ultraviolet radiation (UVR, 280–400 nm) due to vertical mixing within the epilimnion act synergistically with increased DOM to impair cyanobacterial photosynthesis as the water column progressively darkens. The main consequence of such a feed-back response is that these organisms will not develop large blooms in areas of latitudes higher than 30°, in both the Northern and Southern Hemispheres, where DOM inputs and surface wind stress are increasing. PMID:26415603

  17. Revealing the Dynamics of Thylakoid Membranes in Living Cyanobacterial Cells

    NASA Astrophysics Data System (ADS)

    Stingaciu, Laura-Roxana; O’Neill, Hugh; Liberton, Michelle; Urban, Volker S.; Pakrasi, Himadri B.; Ohl, Michael

    2016-01-01

    Cyanobacteria are photosynthetic prokaryotes that make major contributions to the production of the oxygen in the Earth atmosphere. The photosynthetic machinery in cyanobacterial cells is housed in flattened membrane structures called thylakoids. The structural organization of cyanobacterial cells and the arrangement of the thylakoid membranes in response to environmental conditions have been widely investigated. However, there is limited knowledge about the internal dynamics of these membranes in terms of their flexibility and motion during the photosynthetic process. We present a direct observation of thylakoid membrane undulatory motion in vivo and show a connection between membrane mobility and photosynthetic activity. High-resolution inelastic neutron scattering experiments on the cyanobacterium Synechocystis sp. PCC 6803 assessed the flexibility of cyanobacterial thylakoid membrane sheets and the dependence of the membranes on illumination conditions. We observed softer thylakoid membranes in the dark that have three-to four fold excess mobility compared to membranes under high light conditions. Our analysis indicates that electron transfer between photosynthetic reaction centers and the associated electrochemical proton gradient across the thylakoid membrane result in a significant driving force for excess membrane dynamics. These observations provide a deeper understanding of the relationship between photosynthesis and cellular architecture.

  18. Cyanobacterial diversity in the phyllosphere of a mangrove forest.

    PubMed

    Rigonato, Janaina; Alvarenga, Danillo Oliveira; Andreote, Fernando Dini; Dias, Armando Cavalcante Franco; Melo, Itamar Soares; Kent, Angela; Fiore, Marli Fátima

    2012-05-01

    The cyanobacterial community colonizing phyllosphere in a well-preserved Brazilian mangrove ecosystem was assessed using cultivation-independent molecular approaches. Leaves of trees that occupy this environment (Rhizophora mangle,Avicennia schaueriana and Laguncularia racemosa) were collected along a transect beginning at the margin of the bay and extending upland. The results demonstrated that the phyllosphere of R. mangle and L. racemosa harbor similar assemblages of cyanobacteria at each point along the transect. A. schaueriana, found only in the coastal portions of the transect, was colonized by assemblages with lower richness than the other trees. However, the results indicated that spatial location was a stronger driver of cyanobacterial community composition than plant species. Distinct cyanobacterial communities were observed at each location along the coast-to-upland transect. Clone library analysis allowed identification of 19 genera of cyanobacteria and demonstrated the presence of several uncultivated taxa. A predominance of sequences affiliated with the orders Nostocales and Oscillatoriales was observed, with a remarkable number of sequences similar to genera Symphyonemopsis/Brasilonema (order Nostocales). The results demonstrated that phyllosphere cyanobacteria in this mangrove forest ecosystem are influenced by environmental conditions as the primary driver at the ecosystem scale, with tree species exerting some effect on community structure at the local scale.

  19. Use of cyanobacterial diazotrophic technology in rice agriculture

    SciTech Connect

    Tiwari, D.N.; Kumar, A.; Mishra, A.K.

    1991-12-31

    Diazotrophic cyanobacteria are photoautotrophic organisms that require sunlight as a sole energy source for the fixation of carbon and nitrogen. Therefore, they have great potential as biofertilizers, and their use will decrease fuel demand for fertilizer production. The agronomic potential of heterocystous cyanobacteria, either free-living or in symbiotic association with water fern Azolla, has long been recognized. This has led to the development of small scale biotechnology involving the use of paddy soils with appropriate cyanobacterial strains as biofertilizers in rice culture, as has been reported from China, Egypt, Philippines, and India. Besides increasing soil fertility and sustaining rice yield, these forms are also reported to benefit rice seedlings by producing growth-promoting substances, the nature of which is said to resemble gibberellins. Whereas the incorporation of nif genes into the rice plants by using tissue culture and modern genetic tools remain one of the ambitious research goals, the use of cyanobacterial diazotrophic technology in rice agriculture offers an immediate or even long-term alternative to synthetic nitrogen fertilizers, particularly in developing countries and the world as a whole. However, one of the weaknesses in this technology is the heavy application of several toxic agrochemicals, especially herbicides, which are reported in most cases as inhibitors of cyanobacterial diazotrophic growth, and in some cases as mutagenic. Naturally, a successful biotechnology requires the selection of suitable diazotrophic strains, as biofertilizers, that could tolerate the field-dose concentrations of herbicides and secrete ammonia.

  20. Charismatic microfauna alter cyanobacterial production through a trophic cascade

    NASA Astrophysics Data System (ADS)

    Geange, S. W.; Stier, A. C.

    2010-06-01

    The trophic ecology of cyanobacterial blooms is poorly understood on coral reefs. Blooms of toxic cyanobacteria, Lyngbya majuscula, can quickly form large mats. The herbivorous sea hare, Stylocheilus striatus, and the predatory nudibranch, Gymnodoris ceylonica, often associate with these blooms, forming a linear food chain: nudibranch—sea hare—cyanobacteria. Using laboratory studies, this study quantified (1) the functional response of nudibranchs, (2) the effect of sea hare size on predation rates, and (3) the strength of the indirect effect of sea hare predation on cyanobacteria (i.e., a trophic cascade). Nudibranchs consumed on average 2.4 sea hares d-1, with the consumption of small sea hares 22 times greater than the consumption of large sea hares. Predation of sea hares reduced herbivory. Cyanobacterial biomass was 1.5 times greater when nudibranchs were present relative to when nudibranchs were absent. Although sea hare grazing can substantially reduce cyanobacterial biomass, predation of sea hares may mitigate grazing pressure, and therefore increase the abundance of cyanobacteria.

  1. Toxin content and cytotoxicity of algal dietary supplements

    SciTech Connect

    Heussner, A.H.; Mazija, L.; Fastner, J.; Dietrich, D.R.

    2012-12-01

    Blue-green algae (Spirulina sp., Aphanizomenon flos-aquae) and Chlorella sp. are commercially distributed as organic algae dietary supplements. Cyanobacterial dietary products in particular have raised serious concerns, as they appeared to be contaminated with toxins e.g. microcystins (MCs) and consumers repeatedly reported adverse health effects following consumption of these products. The aim of this study was to determine the toxin contamination and the in vitro cytotoxicity of algae dietary supplement products marketed in Germany. In thirteen products consisting of Aph. flos-aquae, Spirulina and Chlorella or mixtures thereof, MCs, nodularins, saxitoxins, anatoxin-a and cylindrospermopsin were analyzed. Five products tested in an earlier market study were re-analyzed for comparison. Product samples were extracted and analyzed for cytotoxicity in A549 cells as well as for toxin levels by (1) phosphatase inhibition assay (PPIA), (2) Adda-ELISA and (3) LC–MS/MS. In addition, all samples were analyzed by PCR for the presence of the mcyE gene, a part of the microcystin and nodularin synthetase gene cluster. Only Aph. flos-aquae products were tested positive for MCs as well as the presence of mcyE. The contamination levels of the MC-positive samples were ≤ 1 μg MC-LR equivalents g{sup −1} dw. None of the other toxins were found in any of the products. However, extracts from all products were cytotoxic. In light of the findings, the distribution and commercial sale of Aph. flos-aquae products, whether pure or mixed formulations, for human consumption appear highly questionable. -- Highlights: ► Marketed algae dietary supplements were analyzed for toxins. ► Methods: Phosphatase inhibition assay (PPIA), Adda-ELISA, LC-MS/MS. ► Aph. flos-aquae products all tested positive for microcystins. ► Products tested negative for nodularins, saxitoxins, anatoxin-a, cylindrospermopsin. ► Extracts from all products were cytotoxic.

  2. Siderophores: The special ingredient to cyanobacterial blooms

    NASA Astrophysics Data System (ADS)

    Du, Xue; Creed, Irena; Trick, Charles

    2013-04-01

    Freshwater lakes provide a number of significant ecological services including clean drinking water, habitat for aquatic biota, and economic benefits. The provision of these ecological services, as well as the health of these aquatic systems, is threatened by the excessive growth of algae, specifically, cyanobacteria. Historically, blooms have been linked to eutrophication but recent occurrences indicate that there are less dramatic changes that induce these blooms. Iron is an essential micronutrient required for specific essential metabolic pathways; however, the amount of biologically available iron in naturally occurring lake ranges from saturation to much lower than cell transport affinities. To assist in the modulation of iron availabilities, cyanobacteria in culture produce low molecular weight compounds that function in an iron binding and acquisition system; nevertheless, this has yet to be confirmed in naturally occurring lakes. This project explored the relationship of P, N and in particular, Fe, in the promotion of cyanobacteria harmful algal blooms in 30 natural freshwater lakes located in and around the Elk Island National Park, Alberta. It is hypothesized that cyanobacteria produce and utilize iron chelators called siderophores in low Fe and nitrogen (N) conditions, creating a competitive advantage over other algae in freshwater lakes. Lakes were selected to represent a range of iron availability to explore the nutrient composition of lakes that propagated cyanobacteria harmful algal blooms (cHABs) compared to lakes that did not. Lake water was analyzed for nutrients, microbial composition, siderophore concentration, and toxin concentration. Modifications were made to optimize the Czaky and Arnow tests for hydroxamate- and catecholate-type siderophores, respectively, for field conditions. Preliminary results indicate the presence of iron-binding ligands (0.11-2.34 mg/L) in freshwater lakes characterized by widely ranging Fe regimes (0.04-2.74 mg

  3. Structural Dynamics of Community Gene Expression In a Freshwater Cyanobacterial Bloom Over a Day-Night Cycle

    NASA Astrophysics Data System (ADS)

    Wang, J.; Fernando, S.; Thompson, J. R.

    2011-12-01

    Cyanobacterial blooms are a major problem in eutrophic lakes and reservoirs, negatively impacting the ecology of the water body through oxygen depletion upon bloom decay and in some cases through production of toxins. Waterborne cyanobacterial toxins pose a public health threat through drinking and recreational exposure. The frequency of harmful cyanobacterial blooms (cyanoHABs) is predicted to increase due to warming regional climates (Paerl et.al, 2011) and increases in non-point source pollution due to urban expansion (Novotny, 2011). CyanoHABs represent complex consortia of cyanobacteria that live in association with diverse assemblages of heterotrophic and anoxygenic photosynthetic bacteria. A better understanding of the structure, function, and interaction between members of the complex microbial communities that support the proliferation of toxigenic cyanobacteria will improve our ability to prevent and control cyanoHABs. Studies of community gene expression, or metatranscriptomics, provide a powerful approach for quantifying changes in both the taxonomic composition (structure) and activity (function) of complex microbial systems in response to dynamic environmental conditions. We have used next-generation Illumina sequencing to characterize the metatranscriptome of a tropical eutrophic drinking water reservoir dominated by the toxigenic cyanobacterium Microcystis aeruginosa over a day/night cycle. Bacterioplankton sampling was carried out at six time points over a 24 hour period to capture variability associated with changes in the balance between phototrophic and heterotrophic activity. Total RNA was extracted and subjected to ribosomal depletion followed by cDNA synthesis and sequencing, generating 493,468 to 678,064 95-101 bp post-quality control reads per sample. Hierarchical Clustering of transcriptional profiles supported sorting of samples into two clusters corresponding to "day" and "night" collection times. Annotation of reads through the MG

  4. Indicators: Algal Toxins (microcystin)

    EPA Pesticide Factsheets

    Algal toxins are toxic substances released by some types of algae (phytoplankton) when they are present in large quantities (blooms) and decay or degrade. High nutrient levels and warm temperatures often result in favorable conditions for algae blooms.

  5. Hydrogen from Water in a Novel Recombinant Oxygen-Tolerant Cyanobacterial System (Presentation)

    SciTech Connect

    Xu, Q.; Smith, H. O.; Maness, P.-C.

    2007-05-01

    The objective of this report is to develop an O{sub 2}-tolerant cyanobacterial system for continuous light-driven H{sub 2} production from water. The overall goal is to produce a cyanobacterial recombinant to produce H{sub 2} continuously.

  6. Molecular Analysis of the Cyanobacterial Community in Gastric Contents of Egrets with Symptoms of Steatitis

    PubMed Central

    Nishizawa, Tomoyasu; Neagari, Yasuko; Miura, Takamasa; Asayama, Munehiko; Murata, Koichi; Harada, Ken-Ichi; Shirai, Makoto

    2015-01-01

    Many deaths of wild birds that have drunk water contaminated with hepatotoxic microcystin-producing cyanobacteria have been reported. A mass death of egrets and herons with steatitis were found at the agricultural reservoir occurring cyanobacterial waterblooms. This study aimed to verify a hypothesis that the egrets and herons which died in the reservoir drink microcystin-producing cyanobacteria and microcystin involves in the cause of death as well as the symptoms of steatitis. The cyanobacterial community in gastric contents of egrets and herons that died from steatitis was assessed using cyanobacterial 16S rRNA-based terminal-restriction fragment length polymorphism (T-RFLP) profiling and a cyanobacterial 16S rRNA-based clone library analysis. In addition, PCR amplification of the mcyB–C region and the mcyG gene, involved in microcystin biosynthesis, was examined. The cyanobacterial community in the gastric contents of two birds showed a simplistic composition. A comparison of cyanobacterial T-RFLP profiling and cloned sequences suggested that the genus Microcystis predominated in both samples of egrets died. Although we confirmed that two egrets which died in the reservoir have taken in cyanobacterial waterblooms containing the genus Microcystis, no mcy gene was detected in both samples according to the mcy gene-based PCR analysis. This study is the first to show the profiling and traceability of a cyanobacterial community in the gastric contents of wild birds by molecular analysis. Additionally, we consider causing symptoms of steatitis in the dead egrets. PMID:26668668

  7. Molecular Analysis of the Cyanobacterial Community in Gastric Contents of Egrets with Symptoms of Steatitis.

    PubMed

    Nishizawa, Tomoyasu; Neagari, Yasuko; Miura, Takamasa; Asayama, Munehiko; Murata, Koichi; Harada, Ken-Ichi; Shirai, Makoto

    2015-01-01

    Many deaths of wild birds that have drunk water contaminated with hepatotoxic microcystin-producing cyanobacteria have been reported. A mass death of egrets and herons with steatitis were found at the agricultural reservoir occurring cyanobacterial waterblooms. This study aimed to verify a hypothesis that the egrets and herons which died in the reservoir drink microcystin-producing cyanobacteria and microcystin involves in the cause of death as well as the symptoms of steatitis. The cyanobacterial community in gastric contents of egrets and herons that died from steatitis was assessed using cyanobacterial 16S rRNA-based terminal-restriction fragment length polymorphism (T-RFLP) profiling and a cyanobacterial 16S rRNA-based clone library analysis. In addition, PCR amplification of the mcyB-C region and the mcyG gene, involved in microcystin biosynthesis, was examined. The cyanobacterial community in the gastric contents of two birds showed a simplistic composition. A comparison of cyanobacterial T-RFLP profiling and cloned sequences suggested that the genus Microcystis predominated in both samples of egrets died. Although we confirmed that two egrets which died in the reservoir have taken in cyanobacterial waterblooms containing the genus Microcystis, no mcy gene was detected in both samples according to the mcy gene-based PCR analysis. This study is the first to show the profiling and traceability of a cyanobacterial community in the gastric contents of wild birds by molecular analysis. Additionally, we consider causing symptoms of steatitis in the dead egrets.

  8. Chlorophyll f distribution and dynamics in cyanobacterial beachrock biofilms.

    PubMed

    Trampe, Erik; Kühl, Michael

    2016-12-01

    Chlorophyll (Chl) f, the most far-red (720-740 nm) absorbing Chl species, was discovered in cyanobacterial isolates from stromatolites and subsequently in other habitats as well. However, the spatial distribution and temporal dynamics of Chl f in a natural habitat have so far not been documented. Here, we report the presence of Chl f in cyanobacterial beachrock biofilms. Hyperspectral imaging on cross-sections of beachrock from Heron Island (Great Barrier Reef, Australia), showed a strong and widely distributed signature of Chl f absorption in an endolithic layer below the dense cyanobacterial surface biofilm that could be localized to aggregates of Chroococcidiopsis-like unicellular cyanobacteria packed within a thick common sheath. High-pressure liquid chromatography-based pigment analyses showed in situ ratios of Chl f to Chl a of 5% in brown-pigmented zones of the beachrock, with lower ratios of ~0.5% in the black- and pink-pigmented biofilm zones. Enrichment experiments with black beachrock biofilm showed stimulated synthesis of Chl f and Chl d when grown under near-infrared radiation (NIR; 740 nm), with a Chl f to Chl a ratio increasing 4-fold to 2%, whereas the Chl d to Chl a ratio went from 0% to 0.8%. Enrichments grown under white light (400-700 nm) produced no detectable amounts of either Chl d or Chl f. Beachrock cyanobacteria thus exhibited characteristics of far-red light photoacclimation, enabling Chl f -containing cyanobacteria to thrive in optical niches deprived of visible light when sufficient NIR is prevalent.

  9. Using a partial least squares (PLS) method for estimating cyanobacterial pigments in eutrophic inland waters

    NASA Astrophysics Data System (ADS)

    Robertson, A. L.; Li, L.; Tedesco, L.; Wilson, J.; Soyeux, E.

    2009-08-01

    Midwestern lakes and reservoirs are commonly exposed to anthropogenic eutrophication. Cyanobacteria thrive in these nutrient rich-waters and some species pose three threats: 1) taste & odor (drinking), 2) toxins (drinking + recreational) and 3) water treatment process disturbance. Managers for drinking water production are interested in the rapid identification of cyanobacterial blooms to minimize effects caused by harmful cyanobacteria. There is potential to monitor cyanobacteria through the remote sensing of two algal pigments: chlorophyll a (CHL) and phycocyanin (PC). Several empirical methods that develop spectral parameters (e.g., simple band ratio) sensitive to these two pigments and map reflectance to the pigment concentration have been used in a number of investigations using field-based spectroradiometers. This study tests a multivariate analysis approach, partial least squares (PLS) regression, for the estimation of CHL and PC. PLS models were trained with 35 spectra collected from three central Indiana reservoirs during a 2007 field campaign with dual-headed Ocean Optics USB4000 field spectroradiometers (355 - 802 nm, nominal 1.0 nm intervals), and CHL and PC concentrations of the corresponding water samples analyzed at Indiana University-Purdue University at Indianapolis. Validation of these models with 19 remaining spectra show that PLS (CHL R2=0.90, slope=0.91, RMSE=20.61 μg/L PC R2=0.65, slope=1.15, RMSE=23.04. μg/L) performed equally well to the band tuning model based on Gitelson et al. 2005 (CHL: R2=0.75, slope=0.84, RMSE=40.16 μg/L PC: R2=0.59, slope=1.14, RMSE=20.24 μg/L).

  10. Cryptoendolithic lichen and cyanobacterial communities of the Ross Desert, Antarctica.

    PubMed

    Friedmann, E I; Hua, M; Ocampo-Friedmann, R

    1988-01-01

    Cryptoendolithic microbial communities in the Ross Desert (McMurdo Dry Valleys) are characterized on the basis of photosynthetic microorganisms and fungi. Two eukaryotic communities (the lichen-dominated and Hemichloris communities) and three cyanobacterial communities (the red Gloeocapsa, Hormathonema-Gloeocapsa, and Chroococcidiopsis communities) are described. Eleven coccoid, one pleurocapsoid, and five filamentous cyanobacteria occurring in these communities are characterized and illustrated. The moisture grade of the rock substrate seems to affect pH, formation of primary iron stain, and the distribution of microbial communities.

  11. Cryptoendolithic lichen and cyanobacterial communities of the Ross Desert, Antarctica

    NASA Technical Reports Server (NTRS)

    Friedmann, E. I.; Hua, M.; Ocampo-Friedmann, R.

    1988-01-01

    Cryptoendolithic microbial communities in the Ross Desert (McMurdo Dry Valleys) are characterized on the basis of photosynthetic microorganisms and fungi. Two eukaryotic communities (the lichen-dominated and Hemichloris communities) and three cyanobacterial communities (the red Gloeocapsa, Hormathonema-Gloeocapsa, and Chroococcidiopsis communities) are described. Eleven coccoid, one pleurocapsoid, and five filamentous cyanobacteria occurring in these communities are characterized and illustrated. The moisture grade of the rock substrate seems to affect pH, formation of primary iron stain, and the distribution of microbial communities.

  12. Targeted silencing of anthrax toxin receptors protects against anthrax toxins.

    PubMed

    Arévalo, Maria T; Navarro, Ashley; Arico, Chenoa D; Li, Junwei; Alkhatib, Omar; Chen, Shan; Diaz-Arévalo, Diana; Zeng, Mingtao

    2014-05-30

    Anthrax spores can be aerosolized and dispersed as a bioweapon. Current postexposure treatments are inadequate at later stages of infection, when high levels of anthrax toxins are present. Anthrax toxins enter cells via two identified anthrax toxin receptors: tumor endothelial marker 8 (TEM8) and capillary morphogenesis protein 2 (CMG2). We hypothesized that host cells would be protected from anthrax toxins if anthrax toxin receptor expression was effectively silenced using RNA interference (RNAi) technology. Thus, anthrax toxin receptors in mouse and human macrophages were silenced using targeted siRNAs or blocked with specific antibody prior to challenge with anthrax lethal toxin. Viability assays were used to assess protection in macrophages treated with specific siRNA or antibody as compared with untreated cells. Silencing CMG2 using targeted siRNAs provided almost complete protection against anthrax lethal toxin-induced cytotoxicity and death in murine and human macrophages. The same results were obtained by prebinding cells with specific antibody prior to treatment with anthrax lethal toxin. In addition, TEM8-targeted siRNAs also offered significant protection against lethal toxin in human macrophage-like cells. Furthermore, silencing CMG2, TEM8, or both receptors in combination was also protective against MEK2 cleavage by lethal toxin or adenylyl cyclase activity by edema toxin in human kidney cells. Thus, anthrax toxin receptor-targeted RNAi has the potential to be developed as a life-saving, postexposure therapy against anthrax.

  13. Evolutionary analysis of Arabidopsis, cyanobacterial, and chloroplast genomes reveals plastid phylogeny and thousands of cyanobacterial genes in the nucleus

    PubMed Central

    Martin, William; Rujan, Tamas; Richly, Erik; Hansen, Andrea; Cornelsen, Sabine; Lins, Thomas; Leister, Dario; Stoebe, Bettina; Hasegawa, Masami; Penny, David

    2002-01-01

    Chloroplasts were once free-living cyanobacteria that became endosymbionts, but the genomes of contemporary plastids encode only ≈5–10% as many genes as those of their free-living cousins, indicating that many genes were either lost from plastids or transferred to the nucleus during the course of plant evolution. Previous estimates have suggested that between 800 and perhaps as many as 2,000 genes in the Arabidopsis genome might come from cyanobacteria, but genome-wide phylogenetic surveys that could provide direct estimates of this number are lacking. We compared 24,990 proteins encoded in the Arabidopsis genome to the proteins from three cyanobacterial genomes, 16 other prokaryotic reference genomes, and yeast. Of 9,368 Arabidopsis proteins sufficiently conserved for primary sequence comparison, 866 detected homologues only among cyanobacteria and 834 other branched with cyanobacterial homologues in phylogenetic trees. Extrapolating from these conserved proteins to the whole genome, the data suggest that ≈4,500 of Arabidopsis protein-coding genes (≈18% of the total) were acquired from the cyanobacterial ancestor of plastids. These proteins encompass all functional classes, and the majority of them are targeted to cell compartments other than the chloroplast. Analysis of 15 sequenced chloroplast genomes revealed 117 nuclear-encoded proteins that are also still present in at least one chloroplast genome. A phylogeny of chloroplast genomes inferred from 41 proteins and 8,303 amino acids sites indicates that at least two independent secondary endosymbiotic events have occurred involving red algae and that amino acid composition bias in chloroplast proteins strongly affects plastid genome phylogeny. PMID:12218172

  14. Evolutionary analysis of Arabidopsis, cyanobacterial, and chloroplast genomes reveals plastid phylogeny and thousands of cyanobacterial genes in the nucleus.

    PubMed

    Martin, William; Rujan, Tamas; Richly, Erik; Hansen, Andrea; Cornelsen, Sabine; Lins, Thomas; Leister, Dario; Stoebe, Bettina; Hasegawa, Masami; Penny, David

    2002-09-17

    Chloroplasts were once free-living cyanobacteria that became endosymbionts, but the genomes of contemporary plastids encode only approximately 5-10% as many genes as those of their free-living cousins, indicating that many genes were either lost from plastids or transferred to the nucleus during the course of plant evolution. Previous estimates have suggested that between 800 and perhaps as many as 2,000 genes in the Arabidopsis genome might come from cyanobacteria, but genome-wide phylogenetic surveys that could provide direct estimates of this number are lacking. We compared 24,990 proteins encoded in the Arabidopsis genome to the proteins from three cyanobacterial genomes, 16 other prokaryotic reference genomes, and yeast. Of 9,368 Arabidopsis proteins sufficiently conserved for primary sequence comparison, 866 detected homologues only among cyanobacteria and 834 other branched with cyanobacterial homologues in phylogenetic trees. Extrapolating from these conserved proteins to the whole genome, the data suggest that approximately 4,500 of Arabidopsis protein-coding genes ( approximately 18% of the total) were acquired from the cyanobacterial ancestor of plastids. These proteins encompass all functional classes, and the majority of them are targeted to cell compartments other than the chloroplast. Analysis of 15 sequenced chloroplast genomes revealed 117 nuclear-encoded proteins that are also still present in at least one chloroplast genome. A phylogeny of chloroplast genomes inferred from 41 proteins and 8,303 amino acids sites indicates that at least two independent secondary endosymbiotic events have occurred involving red algae and that amino acid composition bias in chloroplast proteins strongly affects plastid genome phylogeny.

  15. Variations in the mosquito larvicidal activities of toxins from Bacillus thuringiensis ssp. israelensis.

    PubMed

    Otieno-Ayayo, Zachariah Ngalo; Zaritsky, Arieh; Wirth, Margaret C; Manasherob, Robert; Khasdan, Vadim; Cahan, Rivka; Ben-Dov, Eitan

    2008-09-01

    Comparing activities of purified toxins from Bacillus thuringiensis ssp. israelensis against larvae of seven mosquito species (vectors of tropical diseases) that belong to three genera, gleaned from the literature, disclosed highly significant variations in the levels of LC(50) as well as in the hierarchy of susceptibilities. Similar toxicity comparisons were performed between nine transgenic Gram-negative species, four of which are cyanobacterial, expressing various combinations of cry genes, cyt1Aa and p20, against larvae of four mosquito species as potential agents for biological control. Reasons for inconsistencies are listed and discussed. Standard conditions for toxin isolation and presentation to larvae are sought. A set of lyophilized powders prepared identically from six Escherichia coli clones expressing combinations of four genes displayed toxicities against larvae of three mosquito species, with levels that differed between them but with identical hierarchy.

  16. Naturally Occurring Food Toxins

    PubMed Central

    Dolan, Laurie C.; Matulka, Ray A.; Burdock, George A.

    2010-01-01

    Although many foods contain toxins as a naturally-occurring constituent or, are formed as the result of handling or processing, the incidence of adverse reactions to food is relatively low. The low incidence of adverse effects is the result of some pragmatic solutions by the US Food and Drug Administration (FDA) and other regulatory agencies through the creative use of specifications, action levels, tolerances, warning labels and prohibitions. Manufacturers have also played a role by setting limits on certain substances and developing mitigation procedures for process-induced toxins. Regardless of measures taken by regulators and food producers to protect consumers from natural food toxins, consumption of small levels of these materials is unavoidable. Although the risk for toxicity due to consumption of food toxins is fairly low, there is always the possibility of toxicity due to contamination, overconsumption, allergy or an unpredictable idiosyncratic response. The purpose of this review is to provide a toxicological and regulatory overview of some of the toxins present in some commonly consumed foods, and where possible, discuss the steps that have been taken to reduce consumer exposure, many of which are possible because of the unique process of food regulation in the United States. PMID:22069686

  17. Contribution of cyanobacterial alkane production to the ocean hydrocarbon cycle.

    PubMed

    Lea-Smith, David J; Biller, Steven J; Davey, Matthew P; Cotton, Charles A R; Perez Sepulveda, Blanca M; Turchyn, Alexandra V; Scanlan, David J; Smith, Alison G; Chisholm, Sallie W; Howe, Christopher J

    2015-11-03

    Hydrocarbons are ubiquitous in the ocean, where alkanes such as pentadecane and heptadecane can be found even in waters minimally polluted with crude oil. Populations of hydrocarbon-degrading bacteria, which are responsible for the turnover of these compounds, are also found throughout marine systems, including in unpolluted waters. These observations suggest the existence of an unknown and widespread source of hydrocarbons in the oceans. Here, we report that strains of the two most abundant marine cyanobacteria, Prochlorococcus and Synechococcus, produce and accumulate hydrocarbons, predominantly C15 and C17 alkanes, between 0.022 and 0.368% of dry cell weight. Based on global population sizes and turnover rates, we estimate that these species have the capacity to produce 2-540 pg alkanes per mL per day, which translates into a global ocean yield of ∼ 308-771 million tons of hydrocarbons annually. We also demonstrate that both obligate and facultative marine hydrocarbon-degrading bacteria can consume cyanobacterial alkanes, which likely prevents these hydrocarbons from accumulating in the environment. Our findings implicate cyanobacteria and hydrocarbon degraders as key players in a notable internal hydrocarbon cycle within the upper ocean, where alkanes are continually produced and subsequently consumed within days. Furthermore we show that cyanobacterial alkane production is likely sufficient to sustain populations of hydrocarbon-degrading bacteria, whose abundances can rapidly expand upon localized release of crude oil from natural seepage and human activities.

  18. A Census of Nuclear Cyanobacterial Recruits in the Plant Kingdom

    PubMed Central

    Wang, Yuesheng; Chen, Mingjie; Yang, Zhaowan; Ma, Chuang; Guo, An-Yuan; Zhou, Yanhong; Chang, Junli; Yang, Guangxiao; He, Guangyuan

    2015-01-01

    The plastids and mitochondria of the eukaryotic cell are of endosymbiotic origin. These events occurred ~2 billion years ago and produced significant changes in the genomes of the host and the endosymbiont. Previous studies demonstrated that the invasion of land affected plastids and mitochondria differently and that the paths of mitochondrial integration differed between animals and plants. Other studies examined the reasons why a set of proteins remained encoded in the organelles and were not transferred to the nuclear genome. However, our understanding of the functional relations of the transferred genes is insufficient. In this paper, we report a high-throughput phylogenetic analysis to identify genes of cyanobacterial origin for plants of different levels of complexity: Arabidopsis thaliana, Chlamydomonas reinhardtii, Physcomitrella patens, Populus trichocarpa, Selaginella moellendorffii, Sorghum bicolor, Oryza sativa, and Ostreococcus tauri. Thus, a census of cyanobacterial gene recruits and a study of their function are presented to better understand the functional aspects of plastid symbiogenesis. From algae to angiosperms, the GO terms demonstrated a gradual expansion over functionally related genes in the nuclear genome, beginning with genes related to thylakoids and photosynthesis, followed by genes involved in metabolism, and finally with regulation-related genes, primarily in angiosperms. The results demonstrate that DNA is supplied to the nuclear genome on a permanent basis with no regard to function, and only what is needed is kept, which thereby expands on the GO space along the related genes. PMID:25794152

  19. Bioremediation of hexavalent chromium by a cyanobacterial mat

    NASA Astrophysics Data System (ADS)

    Shukla, Dhara; Vankar, Padma S.; Srivastava, Sarvesh Kumar

    2012-12-01

    The study comprises the use of cyanobacterial mat (collected from tannery effluent site) to remove hexavalent chromium. This mat was consortium of cyanobacteria/blue-green algae such as Chlorella sp., Phormidium sp. and Oscillatoria sp. The adsorption experiments were carried out in batches using chromium concentrations 2-10, 15-30 and 300 ppm at pH 5.5-6.2. The adsorption started within 15 min; however, 96 % reduction in metal concentration was observed within 210 min. The adsorption phenomenon was confirmed by Fourier transform-infrared spectroscopy and energy dispersive X-ray analysis. This biosorption fitted Freundlich adsorption isotherm very well. It was observed that the best adsorption was at 4 ppm, and at 25 ppm in the chosen concentration ranges. Scanning electron micrograph showed the physiology of mat, indicating sites for metal uptake. The main focus was collection of the cyanobacterial mat from local environments and its chromium removal potential at pH 5.5-6.2.

  20. Contribution of cyanobacterial alkane production to the ocean hydrocarbon cycle

    PubMed Central

    Lea-Smith, David J.; Biller, Steven J.; Davey, Matthew P.; Cotton, Charles A. R.; Perez Sepulveda, Blanca M.; Turchyn, Alexandra V.; Scanlan, David J.; Smith, Alison G.; Chisholm, Sallie W.; Howe, Christopher J.

    2015-01-01

    Hydrocarbons are ubiquitous in the ocean, where alkanes such as pentadecane and heptadecane can be found even in waters minimally polluted with crude oil. Populations of hydrocarbon-degrading bacteria, which are responsible for the turnover of these compounds, are also found throughout marine systems, including in unpolluted waters. These observations suggest the existence of an unknown and widespread source of hydrocarbons in the oceans. Here, we report that strains of the two most abundant marine cyanobacteria, Prochlorococcus and Synechococcus, produce and accumulate hydrocarbons, predominantly C15 and C17 alkanes, between 0.022 and 0.368% of dry cell weight. Based on global population sizes and turnover rates, we estimate that these species have the capacity to produce 2–540 pg alkanes per mL per day, which translates into a global ocean yield of ∼308–771 million tons of hydrocarbons annually. We also demonstrate that both obligate and facultative marine hydrocarbon-degrading bacteria can consume cyanobacterial alkanes, which likely prevents these hydrocarbons from accumulating in the environment. Our findings implicate cyanobacteria and hydrocarbon degraders as key players in a notable internal hydrocarbon cycle within the upper ocean, where alkanes are continually produced and subsequently consumed within days. Furthermore we show that cyanobacterial alkane production is likely sufficient to sustain populations of hydrocarbon-degrading bacteria, whose abundances can rapidly expand upon localized release of crude oil from natural seepage and human activities. PMID:26438854

  1. Light irradiance and spectral distribution effects on cyanobacterial hydrogen production

    NASA Astrophysics Data System (ADS)

    Fatihah Salleh, Siti; Kamaruddin, Azlina; Hekarl Uzir, Mohamad; Rahman Mohamed, Abdul; Halim Shamsuddin, Abdul

    2016-03-01

    Light is an essential energy source for photosynthetic cyanobacteria. Changes in both light irradiance and spectral distribution will affect their photosynthetic productivity. Compared to the light irradiance, little investigations have been carried out on the effect of light spectra towards cyanobacterial hydrogen production. Hence, this work aims to investigate the effects of both light quantity and quality on biohydrogen productivity of heterocystous cyanobacterium, A.variabilis. Under white light condition, the highest hydrogen production rate of 31 µmol H2 mg chl a -1 h-1 was achieved at 70 µE m-2 s-1. When the experiment was repeated at the same light irradiance but different light spectra of blue, red and green, the accumulations of hydrogen were significantly lower than the white light except for blue light. As the light irradiance was increased to 350 µE m-2 s-1, the accumulated hydrogen under the blue light doubled that of the white light. Besides that, an unusual prolongation of the hydrogen production up to 120 h was observed. The results obtained suggest that blue light could be the most desirable light spectrum for cyanobacterial hydrogen production.

  2. Marine Toxins: An Overview

    NASA Astrophysics Data System (ADS)

    Fusetani, Nobuhiro

    Oceans provide enormous and diverse space for marine life. Invertebrates are conspicuous inhabitants in certain zones such as the intertidal; many are soft-bodied, relatively immobile and lack obvious physical defenses. These animals frequently have evolved chemical defenses against predators and overgrowth by fouling organisms. Marine animals may accumulate and use a variety of toxins from prey organisms and from symbiotic microorganisms for their own purposes. Thus, toxic animals are particularly abundant in the oceans. The toxins vary from small molecules to high molecular weight proteins and display unique chemical and biological features of scientific interest. Many of these substances can serve as useful research tools or molecular models for the design of new drugs and pesticides. This chapter provides an initial survey of these toxins and their salient properties.

  3. Polymyositis after ciguatera toxin exposure.

    PubMed

    Stommel, E W; Parsonnet, J; Jenkyn, L R

    1991-08-01

    Biopsy-proved polymyositis subsequently developed in two patients who were severely poisoned by ciguatera fish toxin. Ciguatera toxin may have several mechanisms of action and may represent more than one toxin. The patients' clinical courses and the unlikelihood of coincidence of contracting both diseases suggested to us a causal relationship. Although we cannot prove this relationship, we suggest a mechanism by which the toxin predisposed the muscle to inflammation.

  4. Integrated optical toxin sensor

    NASA Astrophysics Data System (ADS)

    Kelly, Dan; Song, Xuedong; Frayer, Daniel K.; Mendes, Sergio B.; Peyghambarian, Nasser; Swanson, Basil I.; Grace, Karen M.

    1999-12-01

    We have developed a method for simple and highly sensitive detection of multivalent proteins using an optical waveguide sensor. The optical biosensor is based on optically tagged glycolipid receptors imbedded within a fluid phospholipid bilayer membrane formed on the surface of a planar optical waveguide. The binding of multivalent toxin initiates a fluorescence resonance energy transfer resulting in a distinctive spectral signature that is monitored by measuring emitted luminescence above the waveguide surface. The sensor methodology is highly sensitive and specific, and requires no additional reagents or washing steps. Demonstration of the utility of protein-receptor recognition using planar optical waveguides is shown here by the detection of cholera toxin.

  5. Improving the coverage of the cyanobacterial phylum using diversity-driven genome sequencing.

    PubMed

    Shih, Patrick M; Wu, Dongying; Latifi, Amel; Axen, Seth D; Fewer, David P; Talla, Emmanuel; Calteau, Alexandra; Cai, Fei; Tandeau de Marsac, Nicole; Rippka, Rosmarie; Herdman, Michael; Sivonen, Kaarina; Coursin, Therese; Laurent, Thierry; Goodwin, Lynne; Nolan, Matt; Davenport, Karen W; Han, Cliff S; Rubin, Edward M; Eisen, Jonathan A; Woyke, Tanja; Gugger, Muriel; Kerfeld, Cheryl A

    2013-01-15

    The cyanobacterial phylum encompasses oxygenic photosynthetic prokaryotes of a great breadth of morphologies and ecologies; they play key roles in global carbon and nitrogen cycles. The chloroplasts of all photosynthetic eukaryotes can trace their ancestry to cyanobacteria. Cyanobacteria also attract considerable interest as platforms for "green" biotechnology and biofuels. To explore the molecular basis of their different phenotypes and biochemical capabilities, we sequenced the genomes of 54 phylogenetically and phenotypically diverse cyanobacterial strains. Comparison of cyanobacterial genomes reveals the molecular basis for many aspects of cyanobacterial ecophysiological diversity, as well as the convergence of complex morphologies without the acquisition of novel proteins. This phylum-wide study highlights the benefits of diversity-driven genome sequencing, identifying more than 21,000 cyanobacterial proteins with no detectable similarity to known proteins, and foregrounds the diversity of light-harvesting proteins and gene clusters for secondary metabolite biosynthesis. Additionally, our results provide insight into the distribution of genes of cyanobacterial origin in eukaryotic nuclear genomes. Moreover, this study doubles both the amount and the phylogenetic diversity of cyanobacterial genome sequence data. Given the exponentially growing number of sequenced genomes, this diversity-driven study demonstrates the perspective gained by comparing disparate yet related genomes in a phylum-wide context and the insights that are gained from it.

  6. Late Archean mineralised cyanobacterial mats and their modern analogs

    NASA Astrophysics Data System (ADS)

    Kazmierczak, J.; Altermann, W.; Kremer, B.; Kempe, S.; Eriksson, P. G.

    2008-09-01

    Abstract Reported are findings of Neoarchean benthic colonial coccoid cyanobacteria preserved as abundant remnants of mineralized capsules and sheaths visible in SEM images as characteristic patterns after etching highly polished carbonate rock platelets. The samples described herein were collected from the Nauga Formation at Prieska (Kaapvaal craton, South Africa). The stratigraphic position of the sampling horizon (Fig. 1) is bracketed by single zircon ages from intercalated tuffs, of 2588±6 Ma and 2549±7Ma [1]. The cyanobacteria-bearing samples are located within sedimentary sequence which begins with Peritidal Member displaying increasingly transgressive character, passing upward into the Chert Member and followed by the Proto-BIF Member and by the Naute Shale Member of the Nauga Formation successively. All three latter members were deposited below the fair weather wave base. As in our previous report [2], the samples are taken from lenses of massive micritic flat pebble conglomerate occurring in otherwise finely laminated siliceous shales intercalating with thin bedded platy limestone. This part of the Nauga Formation is about 30 m thick. The calcareous, cyanobacteria-bearing flat pebble conglomerate and thin intercalations of fine-grained detrital limestones embedded in the clayey sapropel-rich deposits are interpreted as carbonate sediments winnowed during stormy weather from the nearby located peritidal carbonate platform. The mass occurrence and exceptional preservation of mineralised cyanobacterial remains in the micritic carbonate (Mg-calcite) of the redeposited flat pebbles can be explained by their sudden burial in deeper, probably anoxic clay- and sapropel-rich sediments. When examined with standard petrographic optical microscopic technique, the micritic carbonates show rather obscure structure (Fig. 2a), whereas under the SEM, polished and slightly etched platelets of the same samples reveal surprisingly well preserved patterns (Fig. 2b

  7. Diffusion of Botulinum Toxins

    PubMed Central

    Brodsky, Matthew A.; Swope, David M.; Grimes, David

    2012-01-01

    Background It is generally agreed that diffusion of botulinum toxin occurs, but the extent of the spread and its clinical importance are disputed. Many factors have been suggested to play a role but which have the most clinical relevance is a subject of much discussion. Methods This review discusses the variables affecting diffusion, including protein composition and molecular size as well as injection factors (e.g., volume, dose, injection method). It also discusses data on diffusion from comparative studies in animal models and human clinical trials that illustrate differences between the available botulinum toxin products (onabotulinumtoxinA, abobotulinumtoxinA, incobotulinumtoxinA, and rimabotulinumtoxinB). Results Neither molecular weight nor the presence of complexing proteins appears to affect diffusion; however, injection volume, concentration, and dose all play roles and are modifiable. Both animal and human studies show that botulinum toxin products are not interchangeable, and that some products are associated with greater diffusion and higher rates of diffusion-related adverse events than others. Discussion Each of the botulinum toxins is a unique pharmacologic entity. A working knowledge of the different serotypes is essential to avoid unwanted diffusion-related adverse events. In addition, clinicians should be aware that the factors influencing diffusion may range from properties intrinsic to the drug to accurate muscle selection as well as dilution, volume, and dose injected. PMID:23440162

  8. CYANOBACTERIA AND THEIR TOXINS.

    EPA Science Inventory

    Science Questions

    Harmful algal blooms (HAB) of cyanobacteria, also known as blue-green algae, have recently become more spatially and temporally prevalent in the US and worldwide. Cyanobacteria and their highly potent toxins are a significant hazard for human health and ...

  9. CYANOBACTERIA AND THEIR TOXINS

    EPA Science Inventory

    Science Questions

    Harmful algal blooms (HAB) of cyanobacteria, also known as blue-green algae, have recently become more spatially and temporally prevalent in the US and worldwide. Cyanobacteria and their highly potent toxins are a significant hazard for human health and ...

  10. [Protein toxins of Staphylococcus aureus].

    PubMed

    Shamsutdinov, A F; Tiurin, Iu A

    2014-01-01

    Main scientific-research studies regarding protein bacterial toxins of the most widespread bacteria that belong to Staphylococcus spp. genus and in particular the most pathogenic species for humans--Staphylococcus aureus, are analyzed. Structural and biological properties of protein toxins that have received the name of staphylococcus pyrogenic toxins (PTSAg) are presented. Data regarding genetic regulation of secretion and synthesis of these toxins and 3 main regulatory genetic systems (agr--accessory gene regulator, xpr--extracellular protein regulator, sar--staphylococcal accessory regulator) that coordinate synthesis of the most important protein toxins and enzymes for virulence of S. aureus, are presented.

  11. A pair of chiral flavonolignans as novel anti-cyanobacterial allelochemicals derived from barley straw (Hordeum vulgare): characterization and comparison of their anti-cyanobacterial activities.

    PubMed

    Xiao, Xi; Huang, Haomin; Ge, Zhiwei; Rounge, Trine B; Shi, Jiyan; Xu, Xinhua; Li, Ruobing; Chen, Yingxu

    2014-05-01

    The inhibitory effect of barley straw (Hordeum vulgare) on cyanobacteria has been observed in many field and laboratory studies for over 30 years, although the compounds responsible for this anti-cyanobacterial effect have remained unknown. In this study, a pair of chiral flavonolignans were isolated from barley straw extract using a bioassay-guided isolation procedure against Microcystis sp. The structures of the allelopathic compounds were elucidated by NMR (nuclear magnetic resonance) and HPLC-MS (high performance liquid chromatography-mass spectrometry), and turned out to be salcolin A and B. The enantiomers differ in their anti-cyanobacterial abilities. Both enantiomers exhibited inhibitory effects on Microcystis sp., and the EC50 (concentration for 50% of maximal effect) of salcolin A and B were 6.02 × 10(-5) and 9.60 × 10(-5 ) mol l(-1) , respectively. Furthermore, the modes of actions of the enantiomers were investigated and compared at a single cell level by flow cytometry. Salcolin A was found to induce an increase on cyanobacterial intracellular ROS (reactive oxygen species) levels and to inhibit esterase activity, whereas salcolin B caused leakages of cyanobacterial cytoplasms. Thus, salcolin A was more 'algistatic', and salcolin B was more 'algicidal'. This study suggests that salcolin is the key allelochemical in barley straw's inhibitory effect on cyanobacteria and could be used as an agent in the future control of cyanobacterial harmful algae blooms.

  12. The cyanobacterial nitrogen fixation paradox in natural waters

    PubMed Central

    Paerl, Hans

    2017-01-01

    Nitrogen fixation, the enzymatic conversion of atmospheric N (N 2) to ammonia (NH 3), is a microbially mediated process by which “new” N is supplied to N-deficient water bodies. Certain bloom-forming cyanobacterial species are capable of conducting N 2 fixation; hence, they are able to circumvent N limitation in these waters. However, this anaerobic process is highly sensitive to oxygen, and since cyanobacteria produce oxygen in photosynthesis, they are faced with a paradoxical situation, where one critically important (for supporting growth) biochemical process is inhibited by another. N 2-fixing cyanobacterial taxa have developed an array of biochemical, morphological, and ecological adaptations to minimize the “oxygen problem”; however, none of these allows N 2 fixation to function at a high enough efficiency so that it can supply N needs at the ecosystem scale, where N losses via denitrification, burial, and advection often exceed the inputs of “new” N by N 2 fixation. As a result, most marine and freshwater ecosystems exhibit chronic N limitation of primary production. Under conditions of perpetual N limitation, external inputs of N from human sources (agricultural, urban, and industrial) play a central role in determining ecosystem fertility and, in the case of N overenrichment, excessive primary production or eutrophication. This points to the importance of controlling external N inputs (in addition to traditional phosphorus controls) as a means of ensuring acceptable water quality and safe water supplies. Nitrogen fixation, the enzymatic conversion of atmospheric N 2 to ammonia (NH 3) is a  microbially-mediated process by which “new” nitrogen is supplied to N-deficient water bodies.  Certain bloom-forming cyanobacterial species are capable of conducting N 2 fixation; hence they are able to circumvent nitrogen limitation in these waters. However, this anaerobic process is highly sensitive to oxygen, and since cyanobacteria produce oxygen in

  13. Cyanobacterial Diazotrophy and Earth’s Delayed Oxygenation

    PubMed Central

    Olson, Stephanie L.; Reinhard, Christopher T.; Lyons, Timothy W.

    2016-01-01

    The redox landscape of Earth’s ocean-atmosphere system has changed dramatically throughout Earth history. Although Earth’s protracted oxygenation is undoubtedly the consequence of cyanobacterial oxygenic photosynthesis, the relationship between biological O2 production and Earth’s redox evolution remains poorly understood. Existing models for Earth’s oxygenation cannot adequately explain the nearly 2.5 billion years delay between the origin of oxygenic photosynthesis and the oxygenation of the deep ocean, in large part owing to major deficiencies in our understanding of the coevolution of O2 and Earth’s key biogeochemical cycles (e.g., the N cycle). For example, although possible links between O2 and N scarcity have been previously explored, the consequences of N2 limitation for net biological O2 production have not been examined thoroughly. Here, we revisit the prevailing view that N2 fixation has always been able to keep pace with P supply and discuss the possibility that bioavailable N, rather than P, limited export production for extended periods of Earth’s history. Based on the observation that diazotrophy occurs at the expense of oxygenesis in the modern ocean, we suggest that an N-limited biosphere may be inherently less oxygenic than a P-limited biosphere—and that cyanobacterial diazotrophy was a primary control on the timing and tempo of Earth’s oxygenation by modulating net biogenic O2 fluxes. We further hypothesize that negative feedbacks inhibit the transition between N and P limitation, with the implication that the pervasive accumulation of O2 in Earth’s ocean-atmosphere system may not have been an inevitable consequence of oxygenic photosynthesis by marine cyanobacteria. PMID:27721813

  14. Microalgal and cyanobacterial cultivation: the supply of nutrients.

    PubMed

    Markou, Giorgos; Vandamme, Dries; Muylaert, Koenraad

    2014-11-15

    Microalgae and cyanobacteria are a promising new source of biomass that may complement agricultural crops to meet the increasing global demand for food, feed, biofuels and chemical production. Microalgae and cyanobacteria cultivation does not interfere directly with food production, but care should be taken to avoid indirect competition for nutrient (fertilizer) supply. Microalgae and cyanobacteria production requires high concentrations of essential nutrients (C,N,P,S,K,Fe, etc.). In the present paper the application of nutrients and their uptake by microalgae and cyanobacteria is reviewed. The main focus is on the three most significant nutrients, i.e. carbon, nitrogen and phosphorus; however other nutrients are also reviewed. Nutrients are generally taken up in the inorganic form, but several organic forms of them are also assimilable. Some nutrients do not display any inhibition effect on microalgal or cyanobacterial growth, while others, such as NO2 or NH3 have detrimental effects when present in high concentrations. Nutrients in the gaseous form, such as CO2 and NO face a major limitation which is related mainly to their mass transfer from the gaseous to the liquid state. Since the cultivation of microalgae and cyanobacteria consumes considerable quantities of nutrients, strategies to improve the nutrient application efficiency are needed. Additionally, a promising strategy to improve microalgal and cyanobacterial production sustainability is the utilization of waste streams by recycling of waste nutrients. However, major constraints of using waste streams are the reduction of the range of the biomass applications due to production of contaminated biomass and the possible low bio-availability of some nutrients.

  15. Cyanobacterial Blue Color Formation during Lysis under Natural Conditions

    PubMed Central

    Tsuji, Kiyomi; Tomita, Koji; Hasegawa, Masateru; Bober, Beata; Harada, Ken-Ichi

    2015-01-01

    Cyanobacteria produce numerous volatile organic compounds (VOCs), such as β-cyclocitral, geosmin, and 2-methylisoborneol, which show lytic activity against cyanobacteria. Among these compounds, only β-cyclocitral causes a characteristic color change from green to blue (blue color formation) in the culture broth during the lysis process. In August 2008 and September 2010, the lysis of cyanobacteria involving blue color formation was observed at Lake Tsukui in northern Kanagawa Prefecture, Japan. We collected lake water containing the cyanobacteria and investigated the VOCs, such as β-cyclocitral, β-ionone, 1-propanol, 3-methyl-1-butanol, and 2-phenylethanol, as well as the number of cyanobacterial cells and their damage and pH changes. As a result, the following results were confirmed: the detection of several VOCs, including β-cyclocitral and its oxidation product, 2,2,6-trimethylcyclohexene-1-carboxylic acid; the identification of phycocyanin based on its visible spectrum; the lower pH (6.7 and 5.4) of the lysed samples; and characteristic morphological change in the damaged cyanobacterial cells. We also encountered the same phenomenon on 6 September 2013 in Lake Sagami in northern Kanagawa Prefecture and obtained almost the same results, such as blue color formation, decreasing pH, damaged cells, and detection of VOCs, including the oxidation products of β-cyclocitral. β-Cyclocitral derived from Microcystis has lytic activity against Microcystis itself but has stronger inhibitory activity against other cyanobacteria and algae, suggesting that the VOCs play an important role in the ecology of aquatic environments. PMID:25662969

  16. Global distribution of cyanobacterial ecotypes in the cold biosphere.

    PubMed

    Jungblut, Anne D; Lovejoy, Connie; Vincent, Warwick F

    2010-02-01

    Perennially cold habitats are diminishing as a result of climate change; however, little is known of the diversity or biogeography of microbes that thrive in such environments. Here we use targeted 16S rRNA gene surveys to evaluate the global affinities of cold-dwelling cyanobacteria from lake, stream and ice communities living at the northern limit of High Arctic Canada. Pigment signature analysis by HPLC confirmed the dominance of cyanobacteria in the phototrophic communities of these High Arctic microbial mats, with associated populations of chlorophytes and chromophytes. Microscopic analysis of the cyanobacteria revealed a diverse assemblage of morphospecies grouping into orders Oscillatoriales, Nostocales and Chroococcales. The 16S rRNA gene sequences from six clone libraries grouped into a total of 24 ribotypes, with a diversity in each mat ranging from five ribotypes in ice-based communities to 14 in land-based pond communities. However, no significant differences in composition were observed between these two microbial mat systems. Based on clone-library and phylogenetic analysis, several of the High Arctic ribotypes were found to be >99% similar to Antarctic and alpine sequences, including to taxa previously considered endemic to Antarctica. Among the latter, one High Arctic sequence was found 99.8% similar to Leptolyngbya antarctica sequenced from the Larsemann Hills, Antarctica. More than 68% of all identified ribotypes at each site matched only cyanobacterial sequences from perennially cold terrestrial ecosystems, and were <97.5% similar to sequences from warmer environments. These results imply the global distribution of low-temperature cyanobacterial ecotypes throughout the cold terrestrial biosphere.

  17. Cyanobacterial blue color formation during lysis under natural conditions.

    PubMed

    Arii, Suzue; Tsuji, Kiyomi; Tomita, Koji; Hasegawa, Masateru; Bober, Beata; Harada, Ken-ichi

    2015-04-01

    Cyanobacteria produce numerous volatile organic compounds (VOCs), such as β-cyclocitral, geosmin, and 2-methylisoborneol, which show lytic activity against cyanobacteria. Among these compounds, only β-cyclocitral causes a characteristic color change from green to blue (blue color formation) in the culture broth during the lysis process. In August 2008 and September 2010, the lysis of cyanobacteria involving blue color formation was observed at Lake Tsukui in northern Kanagawa Prefecture, Japan. We collected lake water containing the cyanobacteria and investigated the VOCs, such as β-cyclocitral, β-ionone, 1-propanol, 3-methyl-1-butanol, and 2-phenylethanol, as well as the number of cyanobacterial cells and their damage and pH changes. As a result, the following results were confirmed: the detection of several VOCs, including β-cyclocitral and its oxidation product, 2,2,6-trimethylcyclohexene-1-carboxylic acid; the identification of phycocyanin based on its visible spectrum; the lower pH (6.7 and 5.4) of the lysed samples; and characteristic morphological change in the damaged cyanobacterial cells. We also encountered the same phenomenon on 6 September 2013 in Lake Sagami in northern Kanagawa Prefecture and obtained almost the same results, such as blue color formation, decreasing pH, damaged cells, and detection of VOCs, including the oxidation products of β-cyclocitral. β-Cyclocitral derived from Microcystis has lytic activity against Microcystis itself but has stronger inhibitory activity against other cyanobacteria and algae, suggesting that the VOCs play an important role in the ecology of aquatic environments.

  18. Cyanobacterium sp. host cell and vector for production of chemical compounds in cyanobacterial cultures

    DOEpatents

    Piven, Irina; Friedrich, Alexandra; Duhring, Ulf; Uliczka, Frank; Baier, Kerstin; Inaba, Masami; Shi, Tuo; Wang, Kui; Enke, Heike; Kramer, Dan

    2014-09-30

    A cyanobacterial host cell, Cyanobacterium sp., that harbors at least one recombinant gene for the production of a chemical compounds is provided, as well as vectors derived from an endogenous plasmid isolated from the cell.

  19. Cyanobacterium sp. host cell and vector for production of chemical compounds in Cyanobacterial cultures

    SciTech Connect

    Piven, Irina; Friedrich, Alexandra; Duhring, Ulf; Uliczka, Frank; Baier, Kerstin; Inaba, Masami; Shi, Tuo; Wang, Kui; Enke, Heike; Kramer, Dan

    2016-04-19

    A cyanobacterial host cell, Cyanobacterium sp., that harbors at least one recombinant gene for the production of a chemical compounds is provided, as well as vectors derived from an endogenous plasmid isolated from the cell.

  20. Interactions between a cyanobacterial bloom ( Microcystis) and the submerged aquatic plant Ceratophyllum oryzetorum Kom.

    NASA Astrophysics Data System (ADS)

    Li, Dunhai; Li, Genbao; Chen, Wuxiong; Liu, Yongding

    2009-02-01

    In aquatic ecosystems, macrophytes and phytoplankton are main primary producers, in which macrophyte plays an important role in maintaining clear water state, while phytoplankton often dominates in turbid waterbodies. In the present study, the growth and photosynthetic activity of the submerged aquatic plant Ceratophyllum oryzetorum Kom. in different cell densities of cyanobacterial bloom are studied. The results show that the plant length and fresh mass of C. oryzetorum are promoted by low cyanobacterial cell densities. Medium and high cyanobacterial cell densities, on the contrary, act as inhibitory. Furthermore, the photosynthetic activity of C. oryzetorum is strongly inhibited by high cyanobacterial cell densities. To a certain extent, the growth of cyanobacteria is inhibited by C. oryzetorum, but no significant effect is found in this study.

  1. Cylindrospermopsis in Lake Erie: Testing its association with other cyanobacterial genera and major limnological parameters

    EPA Science Inventory

    We report the first documented observation of the potentially toxic cyanobacterium Cylindrospermopsis in lake Erie and Sandusky Bay in 2005 and quantify the physical and chemical parameters and the cyanobacterial community composition contemporaneous to its occurrence. We hypothe...

  2. Type II Toxin-Antitoxin Systems in the Unicellular Cyanobacterium Synechocystis sp. PCC 6803.

    PubMed

    Kopfmann, Stefan; Roesch, Stefanie K; Hess, Wolfgang R

    2016-07-21

    Bacterial toxin-antitoxin (TA) systems are genetic elements, which are encoded by plasmid as well as chromosomal loci. They mediate plasmid and genomic island maintenance through post-segregational killing mechanisms but may also have milder effects, acting as mobile stress response systems that help certain cells of a population in persisting adverse growth conditions. Very few cyanobacterial TA system have been characterized thus far. In this work, we focus on the cyanobacterium Synechocystis 6803, a widely used model organism. We expand the number of putative Type II TA systems from 36 to 69 plus seven stand-alone components. Forty-seven TA pairs are located on the chromosome and 22 are plasmid-located. Different types of toxins are associated with various antitoxins in a mix and match principle. According to protein domains and experimental data, 81% of all toxins in Synechocystis 6803 likely exhibit RNase activity, suggesting extensive potential for toxicity-related RNA degradation and toxin-mediated transcriptome remodeling. Of particular interest is the Ssr8013-Slr8014 system encoded on plasmid pSYSG, which is part of a larger defense island or the pSYSX system Slr6056-Slr6057, which is linked to a bacterial ubiquitin-like system. Consequently, Synechocystis 6803 is one of the most prolific sources of new information about these genetic elements.

  3. Drivers of cyanobacterial diversity and community composition in mangrove soils in south-east Brazil.

    PubMed

    Rigonato, Janaina; Kent, Angela D; Alvarenga, Danillo O; Andreote, Fernando D; Beirigo, Raphael M; Vidal-Torrado, Pablo; Fiore, Marli F

    2013-04-01

    Cyanobacteria act as primary producers of carbon and nitrogen in nutrient-poor ecosystems such as mangroves. This important group of microorganisms plays a critical role in sustaining the productivity of mangrove ecosystems, but the structure and function of cyanobacteria assemblages can be perturbed by anthropogenic influences. The aim of this work was to assess the community structure and ecological drivers that influence the cyanobacterial community harboured in two Brazilian mangrove soils, and examine the long-term effects of oil contamination on these keystone species. Community fingerprinting results showed that, although cyanobacterial communities are distinct between the two mangroves, the structure and diversity of the assemblages exhibit similar responses to environmental gradients. In each ecosystem, cyanobacteria occupying near-shore areas were similar in composition, indicating importance of marine influences for structuring the community. Analysis of 16S rRNA sequences revealed the presence of diverse cyanobacterial communities in mangrove sediments, with clear differences among mangrove habitats along a transect from shore to forest. While near-shore sites in both mangroves were mainly occupied by Prochlorococcus and Synechococcus genera, sequences retrieved from other mangrove niches were mainly affiliated with uncultured cyanobacterial 16S rRNA. The most intriguing finding was the large number of potentially novel cyanobacteria 16S rRNA sequences obtained from a previously oil-contaminated site. The abundance of cyanobacterial 16S rRNA sequences observed in sites with a history of oil contamination was significantly lower than in the unimpacted areas. This study emphasized the role of environmental drivers in determining the structure of cyanobacterial communities in mangrove soils, and suggests that anthropogenic impacts may also act as ecological filters that select cyanobacterial taxa. These results are an important contribution to our

  4. Nitrogen Forms Influence Microcystin Concentration and Composition via Changes in Cyanobacterial Community Structure

    PubMed Central

    Monchamp, Marie-Eve; Pick, Frances R.; Beisner, Beatrix E.; Maranger, Roxane

    2014-01-01

    The eutrophication of freshwaters is a global health concern as lakes with excess nutrients are often subject to toxic cyanobacterial blooms. Although phosphorus is considered the main element regulating cyanobacterial biomass, nitrogen (N) concentration and more specifically the availability of different N forms may influence the overall toxicity of blooms. In this study of three eutrophic lakes prone to cyanobacterial blooms, we examined the effects of nitrogen species and concentrations and other environmental factors in influencing cyanobacterial community structure, microcystin (MC) concentrations and MC congener composition. The identification of specific MC congeners was of particular interest as they vary widely in toxicity. Different nitrogen forms appeared to influence cyanobacterial community structure leading to corresponding effects on MC concentrations and composition. Total MC concentrations across the lakes were largely explained by a combination of abiotic factors: dissolved organic nitrogen, water temperature and ammonium, but Microcystis spp. biomass was overall the best predictor of MC concentrations. Environmental factors did not appear to affect MC congener composition directly but there were significant associations between specific MC congeners and particular species. Based on redundancy analyses (RDA), the relative biomass of Microcystis aeruginosa was associated with MC-RR, M. wesenbergii with MC-LA and Aphanizomenon flos-aquae with MC-YR. The latter two species are not generally considered capable of MC production. Total nitrogen, water temperature, ammonium and dissolved organic nitrogen influenced the cyanobacterial community structure, which in turn resulted in differences in the dominant MC congener and the overall toxicity. PMID:24427318

  5. Conserved transcriptional responses to cyanobacterial stressors are mediated by alternate regulation of paralogous genes in Daphnia.

    PubMed

    Asselman, Jana; Pfrender, Michael E; Lopez, Jacqueline A; De Coninck, Dieter I M; Janssen, Colin R; Shaw, Joseph R; De Schamphelaere, Karel A C

    2015-04-01

    Despite a significant increase in genomic data, our knowledge of gene functions and their transcriptional responses to environmental stimuli remains limited. Here, we use the model keystone species Daphnia pulex to study environmental responses of genes in the context of their gene family history to better understand the relationship between genome structure and gene function in response to environmental stimuli. Daphnia were exposed to five different treatments, each consisting of a diet supplemented with one of five cyanobacterial species, and a control treatment consisting of a diet of only green algae. Differential gene expression profiles of Daphnia exposed to each of these five cyanobacterial species showed that genes with known functions are more likely to be shared by different expression profiles, whereas genes specific to the lineage of Daphnia are more likely to be unique to a given expression profile. Furthermore, while only a small number of nonlineage-specific genes were conserved across treatment type, there was a high degree of overlap in expression profiles at the functional level. The conservation of functional responses across the different cyanobacterial treatments can be attributed to the treatment-specific expression of different paralogous genes within the same gene family. Comparison with available gene expression data in the literature suggests differences in nutritional composition in diets with cyanobacterial species compared to diets of green algae as a primary driver for cyanobacterial effects on Daphnia. We conclude that conserved functional responses in Daphnia across different cyanobacterial treatments are mediated through alternate regulation of paralogous gene families.

  6. A Computational Analysis of Stoichiometric Constraints and Trade-Offs in Cyanobacterial Biofuel Production

    PubMed Central

    Knoop, Henning; Steuer, Ralf

    2015-01-01

    Cyanobacteria are a promising biological chassis for the synthesis of renewable fuels and chemical bulk commodities. Significant efforts have been devoted to improve the yields of cyanobacterial products. However, while the introduction and heterologous expression of product-forming pathways is often feasible, the interactions and incompatibilities of product synthesis with the host metabolism are still insufficiently understood. In this work, we investigate the stoichiometric properties and trade-offs that underlie cyanobacterial product formation using a computational reconstruction of cyanobacterial metabolism. First, we evaluate the synthesis requirements of a selection of cyanobacterial products of potential biotechnological interest. Second, the large-scale metabolic reconstruction allows us to perform in silico experiments that mimic and predict the metabolic changes that must occur in the transition from a growth-only phenotype to a production-only phenotype. Applied to the synthesis of ethanol, ethylene, and propane, these in silico transition experiments point to bottlenecks and potential modification targets in cyanobacterial metabolism. Our analysis reveals incompatibilities between biotechnological product synthesis and native host metabolism, such as shifts in ATP/NADPH demand and the requirement to reintegrate metabolic by-products. Similar strategies can be employed for a large class of cyanobacterial products to identify potential stoichiometric bottlenecks. PMID:25941672

  7. Toxins and drug discovery.

    PubMed

    Harvey, Alan L

    2014-12-15

    Components from venoms have stimulated many drug discovery projects, with some notable successes. These are briefly reviewed, from captopril to ziconotide. However, there have been many more disappointments on the road from toxin discovery to approval of a new medicine. Drug discovery and development is an inherently risky business, and the main causes of failure during development programmes are outlined in order to highlight steps that might be taken to increase the chances of success with toxin-based drug discovery. These include having a clear focus on unmet therapeutic needs, concentrating on targets that are well-validated in terms of their relevance to the disease in question, making use of phenotypic screening rather than molecular-based assays, and working with development partners with the resources required for the long and expensive development process.

  8. [Cytolethal distending toxins].

    PubMed

    Curová, K; Kmeťová, M; Siegfried, L

    2014-06-01

    Cytolethal distending toxins (CDT) are intracellularly acting proteins which interfere with the eukaryotic cell cycle. They are produced by Gram-negative bacteria with affinity to mucocutaneous surfaces and could play a role in the pathogenesis of various mammalian diseases. The functional toxin is composed of three proteins: CdtB entering the nucleus and by its nuclease activity inducing nuclear fragmentation and chromatin disintegration, CdtA, and CdtC, the two latter being responsible for toxin attachment to the surface of the target cell. Cytotoxic effect of CDT leads to the cell cycle arrest before the cell enters mitosis and to further changes (cell distension and death, apoptosis) depending on the cell type. Thus, CDT may function as a virulence factor in pathogenic bacteria that produce it and thus may contribute to the initiation of certain diseases. Most important are inflammatory bowel diseases caused by intestinal bacteria, periodontitis with Aggregatibacter actinomycetemcomitans as the aetiologic agent and ulcus molle where Haemophilus ducreyi is the causative agent.

  9. Environmental influence on cyanobacteria abundance and microcystin toxin production in a shallow temperate lake.

    PubMed

    Lee, Tammy A; Rollwagen-Bollens, Gretchen; Bollens, Stephen M; Faber-Hammond, Joshua J

    2015-04-01

    The increasing frequency of harmful cyanobacterial blooms in freshwater systems is a commonly recognized problem due to detrimental effects on water quality. Vancouver Lake, a shallow, tidally influenced lake in the flood plain of the Columbia River within the city of Vancouver, WA, USA, has experienced numerous summertime cyanobacterial blooms, dominated by Aphanizomenon sp. and Anabaena sp. Cyanobacteria abundance and toxin (microcystin) levels have been monitored in this popular urban lake for several years; however, no previous studies have identified which cyanobacteria species produce toxins, nor analyzed how changes in environmental variables contribute to the fluctuations in toxic cyanobacteria populations. We used a suite of molecular techniques to analyze water samples from Vancouver Lake over two summer bloom cycles (2009 and 2010). Both intracellular and extracellular microcystin concentrations were measured using an ELISA kit. Intracellular microcystin concentrations exceeded WHO guidelines for recreational waters several times throughout the sampling period. PCR results demonstrated that Microcystis sp. was the sole microcystin-producing cyanobacteria species present in Vancouver Lake, although Microcystis sp. was rarely detected in microscopical counts. qPCR results indicated that the majority of the Microcystis sp. population contained the toxin-producing gene (mcyE), although Microcystis sp. abundance rarely exceeded 1 percent of overall cyanobacteria abundance. Non-metric multidimensional scaling (NMDS) revealed that PO4-P was the main environmental variable influencing the abundance of toxic and non-toxic cyanobacteria, as well as intracellular microcystin concentrations. Our study underscores the importance of using molecular genetic techniques, in addition to traditional microscopy, to assess the importance of less conspicuous species in the dynamics of harmful algal blooms.

  10. Method for detecting biological toxins

    SciTech Connect

    Ligler, F.S.; Campbell, J.R.

    1992-01-01

    Biological toxins are indirectly detected by using polymerase chain reaction to amplify unique nucleic acid sequences coding for the toxins or enzymes unique to toxin synthesis. Buffer, primers coding for the unique nucleic acid sequences and an amplifying enzyme are added to a sample suspected of containing the toxin. The mixture is then cycled thermally to exponentially amplify any of these unique nucleic acid sequences present in the sample. The amplified sequences can be detected by various means, including fluorescence. Detection of the amplified sequences is indicative of the presence of toxin in the original sample. By using more than one set of labeled primers, the method can be used to simultaneously detect several toxins in a sample.

  11. [Today's threat of ricin toxin].

    PubMed

    From, Sławomir; Płusa, Tadeusz

    2015-09-01

    Since the late 70s of the last century there were more than 700 incidents related to the use of the ricin toxin. For this reason, CDC (Center of Disease Control and Prevention) recognized toxin as a biological weapon category B. The lethal dose of ricin toxin after parenteral administration is 0.0001 mg/kg and after oral administration 0.2 mg. The first symptoms of poisoning occur within a few hours after application of toxin as a nausea, vomiting and abdominal pain. In the final stage there are observed: cardiac arrhythmia, collapse and symptoms suggestive of involvement of the central nervous system. Stage immediately preceding death is a state of coma. The ricin toxin is still the substance against which action has no optimal antidote. Developed a vaccine called RiVax is waiting for its registration. It should be pointed out that the availability of a ricin toxin makes it possible to use it for real bioterrorists.

  12. Toxin-producing cyanobacteria in freshwater: a review of the problems, impact on drinking water safety, and efforts for protecting public health.

    PubMed

    Cheung, Melissa Y; Liang, Song; Lee, Jiyoung

    2013-02-01

    Cyanobacteria have adapted to survive in a variety of environments and have been found globally. Toxin-producing cyanobacterial harmful algal blooms (CHABs) have been increasing in frequency worldwide and pose a threat to drinking and recreational water. In this study, the prevalence, impact of CHABs and mitigation efforts were reviewed, focusing on the Lake Erie region and Ohio's inland lakes that have been impacted heavily as an example so that the findings can be transferrable to other parts of the world that face the similar problems due to the CHABs in their freshwater environments. This paper provides a basic introduction to CHABs and their toxins as well as an overview of public health implications including exposure routes, health effects, and drinking water issues, algal bloom advisory practices in Ohio, toxin measurements results in Ohio public water supplies, and mitigation efforts.

  13. Time-dependent alterations in growth, photosynthetic pigments and enzymatic defense systems of submerged Ceratophyllum demersum during exposure to the cyanobacterial neurotoxin anatoxin-a.

    PubMed

    Ha, Mi-Hee; Pflugmacher, Stephan

    2013-08-15

    Recently, aquatic macrophytes have been considered as promising tools for eco-friendly water management with a low running cost. However, only little information is available thus far regarding the metabolic capacity of macrophytes for coping with cyanobacterial toxins (cyanotoxins) in the aquatic environment. Cyanotoxins have become emerging contaminants of great concern due to the high proliferation of cyanobacteria (cyanobacterial bloom) accelerated by eutrophication and climate change. Anatoxin-a, one of the common and major cyanotoxins, is suggested as a high priority water pollutant for regulatory consideration owing to its notoriously rapid mode of action as a neurotoxin. In this study, the time-course metabolic regulation of the submerged macrophyte Ceratophyllum demersum (C. demersum) was investigated during exposure to anatoxin-a at an environmentally relevant concentration (15 μg/L). Biotransformation and antioxidative systems in C. demersum responded positively to anatoxin-a through the promoted synthesis of most of the involved enzymes within 8h. Maximum enzyme activities were exhibited after 24 or 48 h of exposure to anatoxin-a. However, an apparent decline in enzyme activities was also observed at longer exposure duration (168 and 336 h) in company with high steady-state levels of cell internal H₂O₂, which showed its highest level after 48 h. Meanwhile, irreversible inhibitory influence on chlorophyll content (vitality) was noticed, whereas the ratio of carotenoids to total chlorophyll was increased with the increase in exposure duration. Consequently, the reduction in growth (biomass) of C. demersum was observed in sub-chronic exposure to anatoxin-a (8 weeks). Overall results clearly indicate, on the one hand, that anatoxin-a causes negative allelopathic effects on the macrophyte by inducing oxidative stress. On the other hand, the macrophyte might have interactions with anatoxin-a, based on the prompt reaction of its enzymatic defense systems

  14. Pore formation by Cry toxins.

    PubMed

    Soberón, Mario; Pardo, Liliana; Muñóz-Garay, Carlos; Sánchez, Jorge; Gómez, Isabel; Porta, Helena; Bravo, Alejandra

    2010-01-01

    Bacillus thuringiensis (Bt) bacteria produce insecticidal Cry and Cyt proteins used in the biological control of different insect pests. In this review, we will focus on the 3d-Cry toxins that represent the biggest group of Cry proteins and also on Cyt toxins. The 3d-Cry toxins are pore-forming toxins that induce cell death by forming ionic pores into the membrane of the midgut epithelial cells in their target insect. The initial steps in the mode of action include ingestion of the protoxin, activation by midgut proteases to produce the toxin fragment and the interaction with the primary cadherin receptor. The interaction of the monomeric CrylA toxin with the cadherin receptor promotes an extra proteolytic cleavage, where helix alpha-1 of domain I is eliminated and the toxin oligomerization is induced, forming a structure of 250 kDa. The oligomeric structure binds to a secondary receptor, aminopeptidase N or alkaline phosphatase. The secondary receptor drives the toxin into detergent resistant membrane microdomains formingpores that cause osmotic shock, burst of the midgut cells and insect death. Regarding to Cyt toxins, these proteins have a synergistic effect on the toxicity of some Cry toxins. Cyt proteins are also proteolytic activated in the midgut lumen of their target, they bind to some phospholipids present in the mosquito midgut cells. The proposed mechanism of synergism between Cry and Cyt toxins is that Cyt1Aa function as a receptor for Cry toxins. The Cyt1A inserts into midgut epithelium membrane and exposes protein regions that are recognized by Cry11Aa. It was demonstrated that this interaction facilitates the oligomerization of Cry11Aa and also its pore formation activity.

  15. Toxin Plasmids of Clostridium perfringens

    PubMed Central

    Li, Jihong; Adams, Vicki; Bannam, Trudi L.; Miyamoto, Kazuaki; Garcia, Jorge P.; Uzal, Francisco A.; Rood, Julian I.

    2013-01-01

    SUMMARY In both humans and animals, Clostridium perfringens is an important cause of histotoxic infections and diseases originating in the intestines, such as enteritis and enterotoxemia. The virulence of this Gram-positive, anaerobic bacterium is heavily dependent upon its prolific toxin-producing ability. Many of the ∼16 toxins produced by C. perfringens are encoded by large plasmids that range in size from ∼45 kb to ∼140 kb. These plasmid-encoded toxins are often closely associated with mobile elements. A C. perfringens strain can carry up to three different toxin plasmids, with a single plasmid carrying up to three distinct toxin genes. Molecular Koch's postulate analyses have established the importance of several plasmid-encoded toxins when C. perfringens disease strains cause enteritis or enterotoxemias. Many toxin plasmids are closely related, suggesting a common evolutionary origin. In particular, most toxin plasmids and some antibiotic resistance plasmids of C. perfringens share an ∼35-kb region containing a Tn916-related conjugation locus named tcp (transfer of clostridial plasmids). This tcp locus can mediate highly efficient conjugative transfer of these toxin or resistance plasmids. For example, conjugative transfer of a toxin plasmid from an infecting strain to C. perfringens normal intestinal flora strains may help to amplify and prolong an infection. Therefore, the presence of toxin genes on conjugative plasmids, particularly in association with insertion sequences that may mobilize these toxin genes, likely provides C. perfringens with considerable virulence plasticity and adaptability when it causes diseases originating in the gastrointestinal tract. PMID:23699255

  16. Ricin detection: tracking active toxin.

    PubMed

    Bozza, William P; Tolleson, William H; Rosado, Leslie A Rivera; Zhang, Baolin

    2015-01-01

    Ricin is a plant toxin with high bioterrorism potential due to its natural abundance and potency in inducing cell death. Early detection of the active toxin is essential for developing appropriate countermeasures. Here we review concepts for designing ricin detection methods, including mechanism of action of the toxin, advantages and disadvantages of current detection assays, and perspectives on the future development of rapid and reliable methods for detecting ricin in environmental samples.

  17. THE SYNERGY OF BACTERIAL TOXINS,

    DTIC Science & Technology

    TOXINS AND ANTITOXINS, STRENGTH(PHYSIOLOGY), BACTERIA , CLOSTRIDIUM PERFRINGENS, CLOSTRIDIUM TETANI, CLOSTRIDIUM, STAPHYLOCOCCUS, ESCHERICHIA COLI, PROTEUS, ETIOLOGY, ANTIGENS, ANTIBODIES, AMINO ACIDS.

  18. How rising CO2 and global warming may stimulate harmful cyanobacterial blooms.

    PubMed

    Visser, Petra M; Verspagen, Jolanda M H; Sandrini, Giovanni; Stal, Lucas J; Matthijs, Hans C P; Davis, Timothy W; Paerl, Hans W; Huisman, Jef

    2016-04-01

    Climate change is likely to stimulate the development of harmful cyanobacterial blooms in eutrophic waters, with negative consequences for water quality of many lakes, reservoirs and brackish ecosystems across the globe. In addition to effects of temperature and eutrophication, recent research has shed new light on the possible implications of rising atmospheric CO2 concentrations. Depletion of dissolved CO2 by dense cyanobacterial blooms creates a concentration gradient across the air-water interface. A steeper gradient at elevated atmospheric CO2 concentrations will lead to a greater influx of CO2, which can be intercepted by surface-dwelling blooms, thus intensifying cyanobacterial blooms in eutrophic waters. Bloom-forming cyanobacteria display an unexpected diversity in CO2 responses, because different strains combine their uptake systems for CO2 and bicarbonate in different ways. The genetic composition of cyanobacterial blooms may therefore shift. In particular, strains with high-flux carbon uptake systems may benefit from the anticipated rise in inorganic carbon availability. Increasing temperatures also stimulate cyanobacterial growth. Many bloom-forming cyanobacteria and also green algae have temperature optima above 25°C, often exceeding the temperature optima of diatoms and dinoflagellates. Analysis of published data suggests that the temperature dependence of the growth rate of cyanobacteria exceeds that of green algae. Indirect effects of elevated temperature, like an earlier onset and longer duration of thermal stratification, may also shift the competitive balance in favor of buoyant cyanobacteria while eukaryotic algae are impaired by higher sedimentation losses. Furthermore, cyanobacteria differ from eukaryotic algae in that they can fix dinitrogen, and new insights show that the nitrogen-fixation activity of heterocystous cyanobacteria can be strongly stimulated at elevated temperatures. Models and lake studies indicate that the response of

  19. Regulation of Orange Carotenoid Protein Activity in Cyanobacterial Photoprotection.

    PubMed

    Thurotte, Adrien; Lopez-Igual, Rocio; Wilson, Adjélé; Comolet, Léa; Bourcier de Carbon, Céline; Xiao, Fugui; Kirilovsky, Diana

    2015-09-01

    Plants, algae, and cyanobacteria have developed mechanisms to decrease the energy arriving at reaction centers to protect themselves from high irradiance. In cyanobacteria, the photoactive Orange Carotenoid Protein (OCP) and the Fluorescence Recovery Protein are essential elements in this mechanism. Absorption of strong blue-green light by the OCP induces carotenoid and protein conformational changes converting the orange (inactive) OCP into a red (active) OCP. Only the red orange carotenoid protein (OCP(r)) is able to bind to phycobilisomes, the cyanobacterial antenna, and to quench excess energy. In this work, we have constructed and characterized several OCP mutants and focused on the role of the OCP N-terminal arm in photoactivation and excitation energy dissipation. The N-terminal arm largely stabilizes the closed orange OCP structure by interacting with its C-terminal domain. This avoids photoactivation at low irradiance. In addition, it slows the OCP detachment from phycobilisomes by hindering fluorescence recovery protein interaction with bound OCP(r). This maintains thermal dissipation of excess energy for a longer time. Pro-22, at the beginning of the N-terminal arm, has a key role in the correct positioning of the arm in OCP(r), enabling strong OCP binding to phycobilisomes, but is not essential for photoactivation. Our results also show that the opening of the OCP during photoactivation is caused by the movement of the C-terminal domain with respect to the N-terminal domain and the N-terminal arm.

  20. Separation of wind's influence on harmful cyanobacterial blooms.

    PubMed

    Wang, Hua; Zhang, Zhizhang; Liang, Dongfang; du, Hanbei; Pang, Yong; Hu, Kaimin; Wang, Jianjian

    2016-07-01

    Wind is an important physical factor involved in Harmful Cyanobacterial blooms (CyanoHABs). Its integrated influence was separated to three components: (a) Direct Disturbance Impact (DDI) on cyanbacterial proliferation, (b) Indirect Nutrient Impact (INI) by sediment release and (c) Direct Transportation Impact (DTI) by both gentle wind-induced surface drift and wave-generated Stokes drift. By the combination of field investigation, laboratory experiment and numerical simulation their individual contributions to the severe bloom event in May 2007 in Meiliang Bay, Lake Taihu, was explored. Wind synthetically made 10.5 percent promotion to the bloom on May 28, 2007, but the impact varied with locations. DTI was featured with the strongest contribution of wind's impacts on CyanoHABs, while INI stood at the lowest level and DDI played an intermediate role. From the point of whole Meiliang Bay, the influencing weights of DTI, DDI and INI were approximately 48.55%, 32.30% and 19.15% respectively. DTI exerted the higher promotion in the regions of middle-east (ME), southwest (SW) and southeast (SE), and its actual contribution rate on CyanoHABs ranged from 6.41% to 7.46%. Due to the background nutrient load, INI was characterized by a tiny effect with the contribution rate being 2.18% on average. From the south bay to the north, DDI was detected with a decreasing tendency, with the practical contribution rate generally falling from 4.13% to 2.7%.

  1. Insights into the Cyanobacterial Deg/HtrA Proteases

    PubMed Central

    Cheregi, Otilia; Wagner, Raik; Funk, Christiane

    2016-01-01

    Proteins are the main machinery for all living processes in a cell; they provide structural elements, regulate biochemical reactions as enzymes, and are the interface to the outside as receptors and transporters. Like any other machinery proteins have to be assembled correctly and need maintenance after damage, e.g., caused by changes in environmental conditions, genetic mutations, and limitations in the availability of cofactors. Proteases and chaperones help in repair, assembly, and folding of damaged and misfolded protein complexes cost-effective, with low energy investment compared with neo-synthesis. Despite their importance for viability, the specific biological role of most proteases in vivo is largely unknown. Deg/HtrA proteases, a family of serine-type ATP-independent proteases, have been shown in higher plants to be involved in the degradation of the Photosystem II reaction center protein D1. The objective of this review is to highlight the structure and function of their cyanobacterial orthologs. Homology modeling was used to find specific features of the SynDeg/HtrA proteases of Synechocystis sp. PCC 6803. Based on the available data concerning their location and their physiological substrates we conclude that these Deg proteases not only have important housekeeping and chaperone functions within the cell, but also are needed for remodeling the cell exterior. PMID:27252714

  2. Cyanobacterial clock, a stable phase oscillator with negligible intercellular coupling

    PubMed Central

    Amdaoud, M.; Vallade, M.; Weiss-Schaber, C.; Mihalcescu, I.

    2007-01-01

    Accuracy in cellular function has to be achieved despite random fluctuations (noise) in the concentrations of different molecular constituents inside and outside the cell. The circadian oscillator in cyanobacteria is an example of resilience to noise. This resilience could be either the consequence of intercellular communication or the intrinsic property of the built-in biochemical network. Here we investigate the intercellular coupling hypothesis. A short theoretical depiction of interacting noisy phase oscillators, confirmed by numerical simulations, allows us to discriminate the effect of coupling from noise. Experimentally, by studying the phase of concurrent populations of different initial phases, we evaluate a very small upper limit of the intercellular coupling strength. In addition, in situ entrainment experiments confirm our ability to detect a coupling of the circadian oscillator to an external force and to describe explicitly the dynamic change of the mean phase. We demonstrate, therefore, that the cyanobacterial clock stability is a built-in property as the intercellular coupling effect is negligible. PMID:17438272

  3. Microcystin in cyanobacterial blooms in a Chilean lake.

    PubMed

    Campos, V; Cantarero, S; Urrutia, H; Heinze, R; Wirsing, B; Neumann, U; Weckesser, J

    1999-05-01

    Cyanobacterial blooms dominated by Microcystis sp. occurred in lake Rocuant ("marisma", near Concepción/Chile) in February 1995 and 1996. In the bloom samples collected in both years the hepatotoxin microcystin was detected by RP-HPLC in both samples and in the sample of 1995 also by a toxicity assay using primary rat hepatocytes. In the bloom of 1995, the microcystin content of the dry bloom biomass was determined to be 130 micrograms/g on the basis of the RP-HPLC peak area and 800 micrograms/g on the basis of the rat hepatotoxicity assay, respectively. In the bloom of 1996, RP-HPLC analysis revealed a microcystin content of 8.13 micrograms/g bloom material dry weight. In this year no hepatotoxicity was measured using a concentration range up to 0.8 mg (d. w.) of bloom material per ml in the rat hepatotoxicity assay. This is the first report on the detection of microcystins in Chilean water bodies.

  4. Biotechnological and industrial significance of cyanobacterial secondary metabolites.

    PubMed

    Rastogi, Rajesh P; Sinha, Rajeshwar P

    2009-01-01

    Cyanobacteria are considered to be a rich source of novel metabolites of a great importance from a biotechnological and industrial point of view. Some cyanobacterial secondary metabolites (CSMs), exhibit toxic effects on living organisms. A diverse range of these cyanotoxins may have ecological roles as allelochemicals, and could be employed for the commercial development of compounds with applications such as algaecides, herbicides and insecticides. Recently, cyanobacteria have become an attractive source of innovative classes of pharmacologically active compounds showing interesting and exciting biological activities ranging from antibiotics, immunosuppressant, and anticancer, antiviral, antiinflammatory to proteinase-inhibiting agents. A different but not less interesting property of these microorganisms is their capacity of overcoming the toxicity of ultraviolet radiation (UVR) by means of UV-absorbing/screening compounds, such as mycosporine-like amino acids (MAAs) and scytonemin. These last two compounds are true 'multipurpose' secondary metabolites and considered to be natural photoprotectants. In this sense, they may be biotechnologically exploited by the cosmetic industry. Overall CSMs are striking targets in biotechnology and biomedical research, because of their potential applications in agriculture, industry, and especially in pharmaceuticals.

  5. Engineering a Cyanobacterial Cell Factory for Production of Lactic Acid

    PubMed Central

    Angermayr, S. Andreas; Paszota, Michal

    2012-01-01

    Metabolic engineering of microorganisms has become a versatile tool to facilitate production of bulk chemicals, fuels, etc. Accordingly, CO2 has been exploited via cyanobacterial metabolism as a sustainable carbon source of biofuel and bioplastic precursors. Here we extended these observations by showing that integration of an ldh gene from Bacillus subtilis (encoding an l-lactate dehydrogenase) into the genome of Synechocystis sp. strain PCC6803 leads to l-lactic acid production, a phenotype which is shown to be stable for prolonged batch culturing. Coexpression of a heterologous soluble transhydrogenase leads to an even higher lactate production rate and yield (lactic acid accumulating up to a several-millimolar concentration in the extracellular medium) than those for the single ldh mutant. The expression of a transhydrogenase alone, however, appears to be harmful to the cells, and a mutant carrying such a gene is rapidly outcompeted by a revertant(s) with a wild-type growth phenotype. Furthermore, our results indicate that the introduction of a lactate dehydrogenase rescues this phenotype by preventing the reversion. PMID:22865063

  6. Engineering a cyanobacterial cell factory for production of lactic acid.

    PubMed

    Angermayr, S Andreas; Paszota, Michal; Hellingwerf, Klaas J

    2012-10-01

    Metabolic engineering of microorganisms has become a versatile tool to facilitate production of bulk chemicals, fuels, etc. Accordingly, CO(2) has been exploited via cyanobacterial metabolism as a sustainable carbon source of biofuel and bioplastic precursors. Here we extended these observations by showing that integration of an ldh gene from Bacillus subtilis (encoding an l-lactate dehydrogenase) into the genome of Synechocystis sp. strain PCC6803 leads to l-lactic acid production, a phenotype which is shown to be stable for prolonged batch culturing. Coexpression of a heterologous soluble transhydrogenase leads to an even higher lactate production rate and yield (lactic acid accumulating up to a several-millimolar concentration in the extracellular medium) than those for the single ldh mutant. The expression of a transhydrogenase alone, however, appears to be harmful to the cells, and a mutant carrying such a gene is rapidly outcompeted by a revertant(s) with a wild-type growth phenotype. Furthermore, our results indicate that the introduction of a lactate dehydrogenase rescues this phenotype by preventing the reversion.

  7. Synchronized Cycles: An allosteric model of the cyanobacterial circadian oscillator

    NASA Astrophysics Data System (ADS)

    Lubensky, David; van Zon, J. S.; Altena, P.; Ten Wolde, P. R.

    2007-03-01

    In a remarkable experiment, Nakajima et al. [Science, 2005] showed that the 3 cyanobacterial clock proteins KaiA, KaiB, and KaiC are sufficient to generate circadian phosphorylation of KaiC in vitro. This system is thus a rare example of a functioning biochemical circuit that can be reconstituted in the test tube. Theoretically, it presents the further challenge that the only reactions driven out of equilibrium are those associated with KaiC phosphorylation and dephosphorylation. Here, we present a model of the Kai system. At its heart is the assumption, motivated by classical models of allostery, that each KaiC hexamer to tends to be phosphorylated in a cyclic manner. For macroscopic oscillations to be possible, however, the cycles of the different hexamers must be synchronized. We propose a novel synchronisation mechanism that allows us to reproduce a wide range of published data, including temperature compensation of the oscillation period, and to make nontrivial predictions about the effects of varying the concentrations of the Kai proteins.

  8. Lake Level Fluctuations Boost Toxic Cyanobacterial “Oligotrophic Blooms”

    PubMed Central

    Callieri, Cristiana; Bertoni, Roberto; Contesini, Mario; Bertoni, Filippo

    2014-01-01

    Global warming has been shown to strongly influence inland water systems, producing noticeable increases in water temperatures. Rising temperatures, especially when combined with widespread nutrient pollution, directly favour the growth of toxic cyanobacteria. Climate changes have also altered natural water level fluctuations increasing the probability of extreme events as dry periods followed by heavy rains. The massive appearance of Dolichospermum lemmermannii ( = planktonic Anabaena), a toxic species absent from the pelagic zone of the subalpine oligotrophic Lake Maggiore before 2005, could be a consequence of the unusual fluctuations of lake level in recent years. We hypothesized that these fluctuations may favour the cyanobacterium as result of nutrient pulses from the biofilms formed in the littoral zone when the lake level is high. To help verify this, we exposed artificial substrates in the lake, and evaluated their nutrient enrichment and release after desiccation, together with measurements of fluctuations in lake level, precipitation and D.lemmermannii population. The highest percentage of P release and the lowest C∶P molar ratio of released nutrients coincided with the summer appearance of the D.lemmermannii bloom. The P pulse indicates that fluctuations in level counteract nutrient limitation in this lake and it is suggested that this may apply more widely to other oligotrophic lakes. In view of the predicted increase in water level fluctuations due to climate change, it is important to try to minimize such fluctuations in order to mitigate the occurrence of cyanobacterial blooms. PMID:25295866

  9. An allele of the crm gene blocks cyanobacterial circadian rhythms.

    PubMed

    Boyd, Joseph S; Bordowitz, Juliana R; Bree, Anna C; Golden, Susan S

    2013-08-20

    The SasA-RpaA two-component system constitutes a key output pathway of the cyanobacterial Kai circadian oscillator. To date, rhythm of phycobilisome associated (rpaA) is the only gene other than kaiA, kaiB, and kaiC, which encode the oscillator itself, whose mutation causes completely arrhythmic gene expression. Here we report a unique transposon insertion allele in a small ORF located immediately upstream of rpaA in Synechococcus elongatus PCC 7942 termed crm (for circadian rhythmicity modulator), which results in arrhythmic promoter activity but does not affect steady-state levels of RpaA. The crm ORF complements the defect when expressed in trans, but only if it can be translated, suggesting that crm encodes a small protein. The crm1 insertion allele phenotypes are distinct from those of an rpaA null; crm1 mutants are able to grow in a light:dark cycle and have no detectable oscillations of KaiC phosphorylation, whereas low-amplitude KaiC phosphorylation rhythms persist in the absence of RpaA. Levels of phosphorylated RpaA in vivo measured over time are significantly altered compared with WT in the crm1 mutant as well as in the absence of KaiC. Taken together, these results are consistent with the hypothesis that the Crm polypeptide modulates a circadian-specific activity of RpaA.

  10. Cyanobacterial Metabolite Calothrixins: Recent Advances in Synthesis and Biological Evaluation

    PubMed Central

    Xu, Su; Nijampatnam, Bhavitavya; Dutta, Shilpa; Velu, Sadanandan E.

    2016-01-01

    The marine environment is host to unparalleled biological and chemical diversity, making it an attractive resource for the discovery of new therapeutics for a plethora of diseases. Compounds that are extracted from cyanobacteria are of special interest due to their unique structural scaffolds and capacity to produce potent pharmaceutical and biotechnological traits. Calothrixins A and B are two cyanobacterial metabolites with a structural assembly of quinoline, quinone, and indole pharmacophores. This review surveys recent advances in the synthesis and evaluation of the biological activities of calothrixins. Due to the low isolation yields from the marine source and the promise this scaffold holds for anticancer and antimicrobial drugs, organic and medicinal chemists around the world have embarked on developing efficient synthetic routes to produce calothrixins. Since the first review appeared in 2009, 11 novel syntheses of calothrixins have been published in the efforts to develop methods that contain fewer steps and higher-yielding reactions. Calothrixins have shown their potential as topoisomerase I poisons for their cytotoxicity in cancer. They have also been observed to target various aspects of RNA synthesis in bacteria. Further investigation into the exact mechanism for their bioactivity is still required for many of its analogs. PMID:26771620

  11. Botulinum toxin, Quo Vadis?

    PubMed

    Lim, Erle C H; Seet, Raymond C S

    2007-01-01

    Botulinum toxin (BTX), derived from the exotoxin of Clostridium botulinum, cleaves Soluble N-ethylmaleimide-sensitive factor-Attachment protein REceptor (SNARE) proteins, causing chemodenervation of cholinergic neurons. BTX also inhibits exocytosis of vesicles containing norepinephrine, glutamate, substance P and calcitonin gene-related peptide (CGRP) and inhibits expression of the vanilloid receptor. Clinical applications of BTX, which include the treatment of overactive skeletal and smooth muscles, hypersecretory and painful disorders, have increased exponentially since it was first used clinically to treat strabismus more than two decades ago. In this editorial, we discuss reports of new therapeutic indications of BTX, and propose new areas for research.

  12. Botulinum toxin: bioweapon & magic drug.

    PubMed

    Dhaked, Ram Kumar; Singh, Manglesh Kumar; Singh, Padma; Gupta, Pallavi

    2010-11-01

    Botulinum neurotoxins, causative agents of botulism in humans, are produced by Clostridium botulinum, an anaerobic spore-former Gram positive bacillus. Botulinum neurotoxin poses a major bioweapon threat because of its extreme potency and lethality; its ease of production, transport, and misuse; and the need for prolonged intensive care among affected persons. A single gram of crystalline toxin, evenly dispersed and inhaled, can kill more than one million people. The basis of the phenomenal potency of botulinum toxin is enzymatic; the toxin is a zinc proteinase that cleaves neuronal vesicle associated proteins responsible for acetylcholine release into the neuromuscular junction. As a military or terrorist weapon, botulinum toxin could be disseminated via aerosol or by contamination of water or food supplies, causing widespread casualties. A fascinating aspect of botulinum toxin research in recent years has been development of the most potent toxin into a molecule of significant therapeutic utility . It is the first biological toxin which is licensed for treatment of human diseases. In the late 1980s, Canada approved use of the toxin to treat strabismus, in 2001 in the removal of facial wrinkles and in 2002, the FDA in the United States followed suit. The present review focuses on both warfare potential and medical uses of botulinum neurotoxin.

  13. Lymphocyte receptors for pertussis toxin

    SciTech Connect

    Clark, C.G.; Armstrong, G.D. )

    1990-12-01

    We have investigated human T-lymphocyte receptors for pertussis toxin by affinity isolation and photoaffinity labeling procedures. T lymphocytes were obtained from peripheral human blood, surface iodinated, and solubilized in Triton X-100. The iodinated mixture was then passed through pertussis toxin-agarose, and the fractions were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Autoradiography of the fixed, dried gels revealed several bands in the pertussis toxin-bound fraction that were not observed in fractions obtained from histone or fetuin-agarose. Further investigations employed a photoaffinity labeling reagent, sulfosuccinimidyl 2-(p-azido-salicylamido)-1,3'-dithiopropionate, to identify pertussis toxin receptors in freshly isolated peripheral blood monocytic cells, T lymphocytes, and Jurkat cells. In all three cell systems, the pertussis toxin affinity probe specifically labeled a single protein species with an apparent molecular weight of 70,000 that was not observed when the procedure was performed in the presence of excess unmodified pertussis toxin. A protein comparable in molecular weight to the one detected by the photoaffinity labeling technique was also observed among the species that bound to pertussis toxin-agarose. The results suggest that pertussis toxin may bind to a 70,000-Da receptor in human T lymphocytes.

  14. Botulinum toxin: Bioweapon & magic drug

    PubMed Central

    Dhaked, Ram Kumar; Singh, Manglesh Kumar; Singh, Padma; Gupta, Pallavi

    2010-01-01

    Botulinum neurotoxins, causative agents of botulism in humans, are produced by Clostridium botulinum, an anaerobic spore-former Gram positive bacillus. Botulinum neurotoxin poses a major bioweapon threat because of its extreme potency and lethality; its ease of production, transport, and misuse; and the need for prolonged intensive care among affected persons. A single gram of crystalline toxin, evenly dispersed and inhaled, can kill more than one million people. The basis of the phenomenal potency of botulinum toxin is enzymatic; the toxin is a zinc proteinase that cleaves neuronal vesicle associated proteins responsible for acetylcholine release into the neuromuscular junction. As a military or terrorist weapon, botulinum toxin could be disseminated via aerosol or by contamination of water or food supplies, causing widespread casualties. A fascinating aspect of botulinum toxin research in recent years has been development of the most potent toxin into a molecule of significant therapeutic utility. It is the first biological toxin which is licensed for treatment of human diseases. In the late 1980s, Canada approved use of the toxin to treat strabismus, in 2001 in the removal of facial wrinkles and in 2002, the FDA in the United States followed suit. The present review focuses on both warfare potential and medical uses of botulinum neurotoxin. PMID:21149997

  15. Temporal shifts in cyanobacterial communities at different sites on the Nakdong River in Korea.

    PubMed

    Hur, Moonsuk; Lee, Injung; Tak, Bo-Mi; Lee, Hae Jin; Yu, Jae Jeong; Cheon, Se Uk; Kim, Bong-Soo

    2013-12-01

    The studies of cyanobacterial blooms resulting from eutrophication or climate change and investigation of changes in the cyanobacterial community in freshwater environments are critical for the management of drinking water. Therefore, we investigated the cyanobacterial communities at 6 sites along the Nakdong River in South Korea from May 2012 to October 2012 by using high-throughput sequencing techniques and studied their relationship with various geochemical factors at sampling sites. Diverse genera (total of 175 genera) were detected within the cyanobacteria, and changes in their compositions were analyzed. The genus Prochlorococcus predominated in the May samples, especially in those obtained from the upstream part of the river, whereas the relative abundance of Microcystis and Anabaena increased with increase in water temperature. The relationship between the cyanobacterial community and environmental factors was analyzed by canonical correlation analysis, and the correlation between harmful cyanobacteria and chemical factors was analyzed by nonmetric multidimensional scaling ordination. Various environmental factors such as dissolved oxygen, pH, electric conductivity, temperature were found to affect the cyanobacterial communities in the river. The results of this study could help in the management of freshwater environments and in maintenance of drinking water quality.

  16. Long-term influence of cyanobacterial bloom on the immune system of Litopenaeus vannamei.

    PubMed

    Gao, Jiefeng; Zuo, Hongliang; Yang, Linwei; He, Jian-Hui; Niu, Shengwen; Weng, Shaoping; He, Jianguo; Xu, Xiaopeng

    2017-02-01

    Cyanobacteria are ubiquitously distributed in water on the Earth. It has long been known that the cyanobacterial bloom in aquaculture ponds can cause acute and massive deaths of shrimp. However, the long-term and chronic effects of the cyanobacterial bloom on shrimp are still poorly understood. In this study, the immune state of white pacific shrimp, Litopenaeus vannamei, surviving a naturally occurring cyanobacterial bloom was investigated and tracked for 70 d. Compared with the control, the growth of shrimp suffering high concentrations of cyanobacteria was obviously postponed. In these shrimp, the activities of the NF-κB, JAK/STAT and P38 MAPK immune signaling pathways and the expression of many antimicrobial peptide genes were down-regulated, whereas the expression of C-type lectins was significantly up-regulated. Although the mRNA level of lysozyme was reduced, the expression of the invertebrate-type lysozyme gene was increased. Furthermore, the concentration of hemocytes in hemolymph was greatly decreased, but the phagocytic activity of hemocytes was increased. These suggested that the cyanobacterial bloom has significant and complex influences on the immune system of shrimp, and in turn, alteration of the immune state could be a factor by which few shrimp can survive the cyanobacterial bloom. Thus, the current study could help further understand the interactions between the aquaculture water environment and the immune system of shrimp.

  17. Cyanobacterial community composition in Arctic soil crusts at different stages of development.

    PubMed

    Pushkareva, Ekaterina; Pessi, Igor S; Wilmotte, Annick; Elster, Josef

    2015-12-01

    Cyanobacterial diversity in soil crusts has been extensively studied in arid lands of temperate regions, particularly semi-arid steppes and warm deserts. Nevertheless, Arctic soil crusts have received far less attention than their temperate counterparts. Here, we describe the cyanobacterial communities from various types of soil crusts from Svalbard, High Arctic. Four soil crusts at different development stages (ranging from poorly-developed to well-developed soil crusts) were analysed using 454 pyrosequencing of the V3-V4 variable region of the cyanobacterial 16S rRNA gene. Analyses of 95 660 cyanobacterial sequences revealed a dominance of OTUs belonging to the orders Synechococcales, Oscillatoriales and Nostocales. The most dominant OTUs in the four studied sites were related to the filamentous cyanobacteria Leptolyngbya sp. Phylotype richness estimates increased from poorly- to mid-developed soil crusts and decreased in the well-developed lichenized soil crust. Moreover, pH, ammonium and organic carbon concentrations appeared significantly correlated with the cyanobacterial community structure.

  18. Artificially accelerating the reversal of desertification: cyanobacterial inoculation facilitates the succession of vegetation communities.

    PubMed

    Lan, Shubin; Zhang, Qingyi; Wu, Li; Liu, Yongding; Zhang, Delu; Hu, Chunxiang

    2014-01-01

    Desertification has been recognized as a global environmental problem, and one region experiencing ongoing desertification is the eastern edge of Qubqi Desert (Inner Mongolia). To investigate the facilitating effects of cyanobacterial inoculation technology on the desertification control along this steppe-desert transition region, artificial cyanobacterial crusts were constructed with two filamentous cyanobacteria 3 and 8 years ago combined with Salix planting. The results showed that no crusts formed after 3 years of fixation only with Salix planting, whereas after cyanobacterial inoculation, the crusts formed quickly and gradually succeed to moss crusts. During that course, topsoil environments were gradually improved, providing the necessary material basis for the regeneration of vascular plants. In this investigation, total 27 species of vascular plants had regenerated in the experimental region, mainly belonging to Asteraceae, Poaceae, Chenopodiaceae and Leguminosae. Using space time substitution, the dominant species along with the application of cyanobacterial inoculation technology succeeded from Agriophyllum squarrosum ultimately to Leymus chinensis. In addition, it was found that the shady side of the dunes is more conducive to crust development and succession of vegetation communities. Conclusively, our results indicate artificial cyanobacterial inoculation technology is an effective and desirable path for desertification control.

  19. Cyanobacterial community composition in Arctic soil crusts at different stages of development

    PubMed Central

    Pushkareva, Ekaterina; Pessi, Igor S.; Wilmotte, Annick; Elster, Josef

    2015-01-01

    Cyanobacterial diversity in soil crusts has been extensively studied in arid lands of temperate regions, particularly semi-arid steppes and warm deserts. Nevertheless, Arctic soil crusts have received far less attention than their temperate counterparts. Here, we describe the cyanobacterial communities from various types of soil crusts from Svalbard, High Arctic. Four soil crusts at different development stages (ranging from poorly-developed to well-developed soil crusts) were analysed using 454 pyrosequencing of the V3-V4 variable region of the cyanobacterial 16S rRNA gene. Analyses of 95 660 cyanobacterial sequences revealed a dominance of OTUs belonging to the orders Synechococcales, Oscillatoriales and Nostocales. The most dominant OTUs in the four studied sites were related to the filamentous cyanobacteria Leptolyngbya sp. Phylotype richness estimates increased from poorly- to mid-developed soil crusts and decreased in the well-developed lichenized soil crust. Moreover, pH, ammonium and organic carbon concentrations appeared significantly correlated with the cyanobacterial community structure. PMID:26564957

  20. Sedimentary DNA Reveals Cyanobacterial Community Diversity over 200 Years in Two Perialpine Lakes.

    PubMed

    Monchamp, Marie-Eve; Walser, Jean-Claude; Pomati, Francesco; Spaak, Piet

    2016-11-01

    We reconstructed cyanobacterial community structure and phylogeny using DNA that was isolated from layers of stratified sediments spanning 200 years of lake history in the perialpine lakes Greifensee and Lake Zurich (Switzerland). Community analysis based on amplification and sequencing of a 400-nucleotide (nt)-long 16S rRNA fragment specific to Cyanobacteria revealed operational taxonomic units (OTUs) capturing the whole phylum, including representatives of a newly characterized clade termed Melainabacteria, which shares common ancestry with Cyanobacteria and has not been previously described in lakes. The reconstruction of cyanobacterial richness and phylogenetic structure was validated using a data set consisting of 40 years of pelagic microscopic counts from each lake. We identified the OTUs assigned to common taxa known to be present in Greifensee and Lake Zurich and found a strong and significant relationship (adjusted R(2) = 0.89; P < 0.001) between pelagic species richness in water and OTU richness in the sediments. The water-sediment richness relationship varied between cyanobacterial orders, indicating that the richness of Chroococcales and Synechococcales may be underestimated by microscopy. PCR detection of the microcystin synthetase gene mcyA confirmed the presence of potentially toxic cyanobacterial taxa over recent years in Greifensee and throughout the last century in Lake Zurich. The approach presented in this study demonstrates that it is possible to reconstruct past pelagic cyanobacterial communities in lakes where the integrity of the sedimentary archive is well preserved and to explore changes in phylogenetic and functional diversity over decade-to-century timescales.

  1. Toxin-induced hepatic injury.

    PubMed

    Lopez, Annette M; Hendrickson, Robert G

    2014-02-01

    Toxins such as pharmaceuticals, herbals, foods, and supplements may lead to hepatic damage. This damage may range from nonspecific symptoms in the setting of liver test abnormalities to acute hepatic failure. The majority of severe cases of toxin-induced hepatic injury are caused by acetaminophen and ethanol. The most important step in the patient evaluation is to gather an extensive history that includes toxin exposure and exclude common causes of liver dysfunction. Patients whose hepatic dysfunction progresses to acute liver failure may benefit from transfer to a transplant service for further management. Currently, the mainstay in management for most exposures is discontinuing the offending agent. This manuscript will review the incidence, pathophysiology, diagnosis and management of the different forms of toxin-induced hepatic injury and exam in-depth the most common hepatic toxins.

  2. Toxin production by Campylobacter spp.

    PubMed Central

    Wassenaar, T M

    1997-01-01

    Of all the virulence factors that were proposed for Campylobacter jejuni and related species to cause disease in humans, the discovery of toxin production was the most promising but led to a rather confusing and even disappointing stream of data. The discussion of whether proteinaceous exotoxins are relevant in disease remains open. One important reason for this lack of consensus is the anecdotal nature of the literature reports. To provide a basis for an unbiased opinion, this review compiles all described exotoxins, compares their reported properties, and provides a summary of animal model studies and clinical data. The toxins are divided into enterotoxins and cytotoxins and are sorted according to their biochemical properties. Since many Campylobacter toxins have been compared with toxins of other species, some key examples of the latter are also discussed. Future directions of toxin research that appear promising are defined. PMID:9227862

  3. Uremic toxins and oral adsorbents.

    PubMed

    Goto, Shunsuke; Yoshiya, Kunihiko; Kita, Tomoyuki; Fujii, Hideki; Fukagawa, Masafumi

    2011-04-01

    Uremic toxins are associated with various disorders in patients with end-stage renal disease and it is difficult to remove some of these toxins by dialysis. Since some uremic toxins are generated by bacterial metabolites in the colon, oral adsorbents that interfere with the absorption of uremic toxins or their precursors are believed to prevent their accumulation in the body. AST-120 adsorbs various uremic retention solutes in the gastrointestinal system and has potential for providing clinical benefit. Sevelamer hydrochloride binds some harmful compounds in addition to phosphate and seems to have pleiotropic effects that include lowering serum LDL cholesterol levels and reduction of inflammation. The effect of sevelamer hydrochloride on indoxyl sulfate and p-cresol has been shown in an in vitro study; however, in vivo studies in mice or humans did not demonstrate this effect on protein-binding uremic toxins. Oral adsorbents are thus one of the important modalities in the treatment of uremic syndrome.

  4. Immunogenicity of Staphylococcus aureus delta-toxin.

    PubMed Central

    Nolte, F S; Kapral, F A

    1981-01-01

    Studies were conducted to determine the immunogenicity of purified Staphylococcus aureus delta-toxin. Rabbits and guinea pigs immunized with delta-toxin incorporated into a multiple antibody, whereas animals given toxin in saline or toxin in saline with Tween 80 did not produce antibody. The immunoglobulin G (IgG) fraction isolated by chromatography on protein A-Sepharose was examined for the presence of anti-delta-toxin antibody by immunoelectrophoresis, immunodiffusion, quantitative precipitation tests, affinity chromatography, and toxin neutralization tests. Although delta-toxin-specific IgG precipitated the toxin in agar gels, the antibody did not neutralize the toxin's hemolytic activity. Delta-toxin binding to human erythrocyte membranes was demonstrated by indirect immunofluorescent staining of toxin-treated erythrocytes. Images PMID:7014461

  5. Algal toxin profiles in Nigerian coastal waters (Gulf of Guinea) using passive sampling and liquid chromatography coupled to mass spectrometry.

    PubMed

    Zendong, Zita; Kadiri, Medina; Herrenknecht, Christine; Nézan, Elisabeth; Mazzeo, Antonia; Hess, Philipp

    2016-05-01

    Algal toxins may accumulate in fish and shellfish and thus cause poisoning in consumers of seafood. Such toxins and the algae producing them are regularly surveyed in many countries, including Europe, North America, Japan and others. However, very little is known regards the occurrence of such algae and their toxins in most African countries. This paper reports on a survey of phytoplankton and algal toxins in Nigerian coastal waters. Seawater samples were obtained from four sites for phytoplankton identification, on three occasions between the middle of October 2014 and the end of February 2015 (Bar Beach and Lekki in Lagos State, Port Harcourt in Rivers State and Uyo in Akwa Ibom State). The phytoplankton community was generally dominated by diatoms and cyanobacteria; however several species of dinoflagellates were also identified: Dinophysis caudata, Lingulodinium polyedrum and two benthic species of Prorocentrum. Passive samplers (containing Diaion(®) HP-20 resin) were deployed for several 1-week periods on the same four sites to obtain profiles of algal toxins present in the seawater. Quantifiable amounts of okadaic acid (OA) and pectenotoxin 2 (PTX2), as well as traces of dinophysistoxin 1 (DTX1) were detected at several sites. Highest concentrations (60 ng OA g(-1) HP-20 resin) were found at Lekki and Bar Beach stations, which also had the highest salinities. Non-targeted analysis using full-scan high resolution mass spectrometry showed that algal metabolites differed from site to site and for different sampling occasions. Screening against a marine natural products database indicated the potential presence of cyanobacterial compounds in the water column, which was also consistent with phytoplankton analysis. During this study, the occurrence of the marine dinoflagellate toxins OA and PTX2 has been demonstrated in coastal waters of Nigeria, despite unfavourable environmental conditions, with regards to the low salinities measured. Hence shellfish samples

  6. Binding of ATP by pertussis toxin and isolated toxin subunits

    SciTech Connect

    Hausman, S.Z.; Manclark, C.R.; Burns, D.L. )

    1990-07-03

    The binding of ATP to pertussis toxin and its components, the A subunit and B oligomer, was investigated. Whereas, radiolabeled ATP bound to the B oligomer and pertussis toxin, no binding to the A subunit was observed. The binding of ({sup 3}H)ATP to pertussis toxin and the B oligomer was inhibited by nucleotides. The relative effectiveness of the nucleotides was shown to be ATP > GTP > CTP > TTP for pertussis toxin and ATP > GTP > TTP > CTP for the B oligomer. Phosphate ions inhibited the binding of ({sup 3}H)ATP to pertussis toxin in a competitive manner; however, the presence of phosphate ions was essential for binding of ATP to the B oligomer. The toxin substrate, NAD, did not affect the binding of ({sup 3}H)ATP to pertussis toxin, although the glycoprotein fetuin significantly decreased binding. These results suggest that the binding site for ATP is located on the B oligomer and is distinct from the enzymatically active site but may be located near the eukaryotic receptor binding site.

  7. Local nutrient regimes determine site-specific environmental triggers of cyanobacterial and microcystin variability in urban lakes

    NASA Astrophysics Data System (ADS)

    Sinang, S. C.; Reichwaldt, E. S.; Ghadouani, A.

    2014-10-01

    Toxic cyanobacterial blooms in urban lakes present serious health hazards to humans and animals and require effective management strategies. In the management of toxic cyanobacteria blooms, understanding the roles of environmental factors is crucial. To date, a range of environmental factors have been proposed as potential triggers for the spatiotemporal variability of cyanobacterial biomass and microcystins in freshwater systems. However, the environmental triggers of cyanobacteria and microcystin variability remain a subject of debate due to contrasting findings. This issue has raised the question if the environmental triggers are site-specific and unique between water bodies. In this study, we investigated the site-specificity of environmental triggers for cyanobacterial bloom and cyanotoxins dynamics. Our study suggests that cyanobacterial dominance and cyanobacterial microcystin content variability were significantly correlated to phosphorus and iron concentrations. However, the correlations between phosphorus and iron with cyanobacterial biomass and microcystin variability were not consistent between lakes, thus suggesting a site specificity of these environmental factors. The discrepancies in the correlations could be explained by differences in local nutrient concentration and the cyanobacterial community in the systems. The findings of this study suggest that identification of site-specific environmental factors under unique local conditions is an important strategy to enhance positive outcomes in cyanobacterial bloom control measures.

  8. Cyanobacteria and their toxins in treated-water storage reservoirs in Abha city, Saudi Arabia.

    PubMed

    Mohamed, Zakaria A; Al Shehri, Abdulrahman M

    2007-07-01

    Occurrence of toxic cyanobacteria in drinking and recreational waters poses human health at risk as they can release potent toxins into the water. In the present study, open and covered treated-water storage reservoirs as well as their relevant tap waters in Abha city, Saudi Arabia, were surveyed for the presence of cyanobacteria and their toxins. The results revealed the contamination of most open reservoir and tap waters by algae and cyanobacteria, with an abundance of toxigenic species of cyanobacteria. Depending on the results of the Limulus amebocyte lysate (LAL) assay and enzyme linked immunosorbent assay (ELISA), endotoxins and microcystins (MCYSTs) were found in most open reservoir and tap waters at concentrations up to 32 EU ml(-1) and 0.3 microg ml(-1), respectively. The extracts of axenic cultures of most cyanobacterial species isolated from these reservoirs showed activity to LAL assay, with large endotoxin amounts obtained in Calothrix parietina (490 EU g(-1)) and Phormidium tenue (210 EU g(-1)). Based on ELISA and HPLC analysis for these extracts, only C. parietina can produce MCYSTs (202 microg g(-1)) with a profile consisting of MCYST-RR and -LR. This study suggests that open treated-water storage reservoirs should be covered to prevent the presence of cyanobacteria and their toxins in such drinking and recreational waters.

  9. Cyanobacterial-algal cenoses in ordinary chernozems under the impact of different phytoameliorants

    NASA Astrophysics Data System (ADS)

    Dubovik, I. E.; Suyundukov, Ya. T.; Khasanova, R. F.; Shalygina, R. R.

    2016-04-01

    General ecological and taxonomic characteristics of cyanobacterial-algal cenoses in ordinary chernozems under different ameliorative plants (phytoameliorants) were studied in the Trans-Ural region of the Republic of Bashkortostan. A comparative analysis of the taxa of studied cenoses in the soils under leguminous herbs and grasses was performed. The phytoameliorative effect of different herbs and their relationships with cyanobacterial-algal cenoses were examined. Overall, 134 cyanoprokaryotic and algal species belonging to 70 genera, 36 families, 15 orders, and 9 classes were identified. Cyanobacterial-algal cenoses included the divisions of Chlorophyta, Cyanoprokaryota, Xanthophyta, Bacillariophyta, and Euglenophyta. Representatives of Ch-, X-, CF-, and P-forms were the leading ecobiomorphs in the studied cenoses.

  10. Cloning of a marine cyanobacterial promoter for foreign gene expression using a promoter probe vector

    SciTech Connect

    Sode, Koji; Hatano, Naoaki; Tatara, Masahiro

    1996-06-01

    A marine cyanobacterial promoter was cloned to allow efficient foreign gene expression. This was carried out using chloramphenicol acetyl transferase (CAT) as a marker protein. For rapid and simple measurement of CAT activity, a method based on a fluorescently labeled substrate was improved by utilizing HPLC equipped with a flow-through fluorescent spectrophotometer. This method was used in conjunction with a newly constructed promoter probe vector. Cyanobacterial transformants, harboring plasmid containing a cloned 2-kbp marine cyanobacterial genomic fragment, showed a 10-fold higher CAT activity, compared with that achieved using the kanamycin-resistant gene promoter. From the sequence analysis of the cloned fragment, a putative promoter region was found. 20 refs., 7 figs., 2 tabs.

  11. Regulating the Energy Flow in a Cyanobacterial Light-Harvesting Antenna Complex.

    PubMed

    Eisenberg, Ido; Caycedo-Soler, Felipe; Harris, Dvir; Yochelis, Shira; Huelga, Susana F; Plenio, Martin B; Adir, Noam; Keren, Nir; Paltiel, Yossi

    2017-02-16

    Photosynthetic organisms harvest light energy, utilizing the absorption and energy-transfer properties of protein-bound chromophores. Controlling the harvesting efficiency is critical for the optimal function of the photosynthetic apparatus. Here, we show that the cyanobacterial light-harvesting antenna complex may be able to regulate the flow of energy to switch reversibly from efficient energy conversion to photoprotective quenching via a structural change. We isolated cyanobacterial light-harvesting proteins, phycocyanin and allophycocyanin, and measured their optical properties in solution and in an aggregated-desiccated state. The results indicate that energy band structures are changed, generating a switch between the two modes of operation, exciton transfer and quenching, achieved without dedicated carotenoid quenchers. This flexibility can contribute greatly to the large dynamic range of cyanobacterial light-harvesting systems.

  12. [Transformation of carbonate minerals in a cyano-bacterial mat in the course of laboratory modeling].

    PubMed

    Zaĭtseva, L V; Orleanskiĭ, V K; Alekseev, A O; Ushatinskaia, G T; Gerasimenko, L M

    2007-01-01

    A laboratory model of a cyano-bacterial mat with mineral layers of carbonates was used to examine the dynamics of the transformation of calcium-magnesium carbonate under the conditions of a soda lake. The activity of various organisms of the cyanobacterial community results in conditions under which the Ca-Mg carbonate precipitate undergoes changes. The crystal lattice of the initial carbonate is restructured; its mineralogical composition changes depending on the conditions of the mat. In magnesium calcites, which are formed under such low-temperature conditions, a rudimentary cation adjustment can occur with the formation of dolomite domains. These experiments confirm the hypothesis that the dolomite found in stromatolites is of a secondary origin and can be formed in the course of transformation of Ca-Mg carbonates under alkaline conditions in an alkaliphilic cyanobacterial community.

  13. Proteomics with a pinch of salt: A cyanobacterial perspective

    PubMed Central

    Pandhal, Jagroop; Wright, Phillip C; Biggs, Catherine A

    2008-01-01

    Cyanobacteria are ancient life forms and have adapted to a variety of extreme environments, including high salinity. Biochemical, physiological and genetic studies have contributed to uncovering their underlying survival mechanisms, and as recent studies demonstrate, proteomics has the potential to increase our overall understanding further. To date, most salt-related cyanobacterial proteomic studies have utilised gel electrophoresis with the model organism Synechocystis sp. PCC6803. Moreover, focus has been on 2–4% w/v NaCl concentrations within different cellular compartments. Under these conditions, Synechocystis sp. PCC6803 was found to respond and adapt to salt stress through synthesis of general and specific stress proteins, altering the protein composition of extracellular layers, and re-directing control of complex central intermediary pathways. Post-transcriptional control was also predicted through non-correlating transcript level data and identification of protein isoforms. In this paper, we also review technical developments with emphasis on improving the quality and quantity of proteomic data and overcoming the detrimental effects of salt on sample preparation and analysis. Developments in gel-free methods include protein and peptide fractionation workflows, which can increase coverage of the proteome (20% in Synechocystis sp. PCC6803). Quantitative techniques have also improved in accuracy, resulting in confidence in quantitation approaching or even surpassing that seen in transcriptomic techniques (better than 1.5-fold in differential expression). Furthermore, in vivo metabolic labelling and de novo protein sequencing software have improved the ability to apply proteomics to unsequenced environmental isolates. The example used in this review is a cyanobacterium isolated from a Saharan salt lake. PMID:18412952

  14. Soluble CuA domain of cyanobacterial cytochrome c oxidase.

    PubMed

    Paumann, Martina; Lubura, Borjana; Regelsberger, Günther; Feichtinger, Markus; Köllensberger, Gunda; Jakopitsch, Christa; Furtmüller, Paul G; Peschek, Günter A; Obinger, Christian

    2004-03-12

    The genomes of several cyanobacteria show the existence of gene clusters encoding subunits I, II, and III of aa(3)-type cytochrome c oxidase. The enzyme occurs on both plasma and thylakoid membranes of these oxygenic phototrophic prokaryotes. Here we report the expression and purification of a truncated subunit II copper A (Cu(A)) domain (i.e. the electron entry and donor binding site) of cytochrome c oxidase from the cyanobacterium Synechocystis PCC 6803 in high yield. The water-soluble purple redox-active bimetallic center displays a relatively low standard reduction potential of 216 mV. Its absorption spectrum at pH 7 is similar to that of other soluble fragments from aa(3)-type oxidases, but the insensitivity of both absorbance and circular dichroism spectra to pH suggests that it is less exposed to the aqueous milieu compared with other Cu(A) domains. Oxidation of horse heart cytochrome c by the bimetallic center follows monophasic kinetics. At pH 7 and low ionic strength the bimolecular rate constant is (2.1 +/- 0.3) x 10(4) m-1 s(-1), and the rates decrease upon the increase of ionic strength. Sequence alignment and modeling of cyanobacterial Cu(A) domains show several peculiarities such as: (i) a large insertion located between the second transmembrane region and the putative hydrophobic cytochrome c docking site, (ii) the lack of acidic residues shown to be important in the interaction between cytochrome c and Paracoccus Cu(A) domain, and (iii) an extended C terminus similar to Escherichia coli ubiquinol oxidase.

  15. Total synthesis of the marine cyanobacterial cyclodepsipeptide apratoxin A

    PubMed Central

    Chen, Jiehao; Forsyth, Craig J.

    2004-01-01

    A total synthesis of apratoxin A was developed. Apratoxin A, isolated from Lyngbya spp. cyanobacteria, is representative of a growing class of marine cyanobacterial cyclodepsipeptides wherein discrete polypeptide and polyketide domains are merged by ester and amide or amide-derived linkages. In the apratoxins, the N terminus of the peptide domain [(Pro)-(N-Me-Ile)-(N-Me-ala)-(O-Me-Tyr)-(moCys)] is a modified vinylogous cysteine that is joined to a novel ketide [3,7-dihydroxy-2,5,8,8-tetramethylnonanoic acid (Dtna)] by an acid-sensitive thiazoline. The C-terminal proline is esterified to a hindered hydroxyl vicinal to the ketide's tert-butyl terminus. Major synthetic challenges included assembly and maintenance the thiazoline-containing moiety and macrolide formation involving acylation of the C39 hydroxyl. The Dtna domain was assembled in the biogenetic direction beginning with a Brown allylation of trimethylacetaldehyde to establish the C39 alcohol configuration. Diastereofacial selective addition of a higher-order dimethylcuprate upon a ring-closing metathesis-derived α,β-unsaturated valerolactone installed the C37 methyl-bearing center. A Paterson anti-aldol process was used to incorporate the remaining two ketide stereogenic centers at C34 and C35. Although attempts to incorporate the thiazoline moiety by condensations of thiol esters bearing α-amino carbamate derivatives failed, an intramolecular Staudinger reduction–aza-Wittig process using α-azido thiol esters was uniquely successful. Late-stage macrocycle closure proceeded well by lactam formation between Pro and N-Me-Ile residues, but attempted lactonizations of the Pro carboxylate with the C39 hydroxyl failed. Optimization of C35 hydroxyl group protection-deprotection completed the effort, which culminated in the first total synthesis of apratoxin A and will enable analog generation toward improving differential cytotoxicity. PMID:15231999

  16. Anti-cyanobacterial activity of Moringa oleifera seeds

    PubMed Central

    Beekman, Wendy

    2009-01-01

    Filtrates from crushed Moringa oleifera seeds were tested for their effects on growth and Photosystem II efficiency of the common bloom-forming cyanobacterium Microcystis aeruginosa. M. aeruginosa populations exhibited good growth in controls and treatments with 4- and 8-mg crushed Moringa seeds per liter, having similar growth rates of 0.50 (±0.01) per day. In exposures of 20- to 160-mg crushed Moringa seeds L−1, growth rates were negative and on average −0.23 (±0.05) .day−1. Presumably, in the higher doses of 20- to 160-mg crushed seeds per liter, the cyanobacteria died, which was supported by a rapid drop in the Photosystem II efficiency (ΦPSII), while the ΦPSII was high and unaffected in 0, 4, and 8 mg L−1. High-density populations of M. aeruginosa (chlorophyll-a concentrations of ∼270 µg L−1) were reduced to very low levels within 2 weeks of exposure to ≥80-mg crushed seeds per liter. At the highest dosage of 160 mg L−1, the ΦPSII dropped to zero rapidly and remained nil during the course of the experiment (14 days). Hence, under laboratory conditions, a complete wipeout of the bloom could be achieved. This is the first study that yielded evidence for cyanobactericidal activity of filtrate from crushed Moringa seeds, suggesting that Moringa seed extracts might have a potential as an effect-oriented measure lessening cyanobacterial nuisance. PMID:20676212

  17. Plastid-localized amino acid biosynthetic pathways of Plantae are predominantly composed of non-cyanobacterial enzymes

    PubMed Central

    Reyes-Prieto, Adrian; Moustafa, Ahmed

    2012-01-01

    Studies of photosynthetic eukaryotes have revealed that the evolution of plastids from cyanobacteria involved the recruitment of non-cyanobacterial proteins. Our phylogenetic survey of >100 Arabidopsis nuclear-encoded plastid enzymes involved in amino acid biosynthesis identified only 21 unambiguous cyanobacterial-derived proteins. Some of the several non-cyanobacterial plastid enzymes have a shared phylogenetic origin in the three Plantae lineages. We hypothesize that during the evolution of plastids some enzymes encoded in the host nuclear genome were mistargeted into the plastid. Then, the activity of those foreign enzymes was sustained by both the plastid metabolites and interactions with the native cyanobacterial enzymes. Some of the novel enzymatic activities were favored by selective compartmentation of additional complementary enzymes. The mosaic phylogenetic composition of the plastid amino acid biosynthetic pathways and the reduced number of plastid-encoded proteins of non-cyanobacterial origin suggest that enzyme recruitment underlies the recompartmentation of metabolic routes during the evolution of plastids. PMID:23233874

  18. Cyanobacterial composition and spatial distribution based on pyrosequencing data in the Gurbantunggut Desert, Northwestern China.

    PubMed

    Zhang, Bingchang; Li, Renhui; Xiao, Peng; Su, Yangui; Zhang, Yuanming

    2016-03-01

    Cyanobacteria are the primary colonizers and form a dominant component of soil photosynthetic communities in biological soil crusts. They are crucial in improving soil environments, namely accumulating soil carbon and nitrogen. Many classical studies have examined cyanobacterial diversity in desert crusts, but relatively few comprehensive molecular surveys have been conducted. We used 454 pyrosequencing of 16S rRNA to investigate cyanobacterial composition and distribution on regional scales in the Gurbantunggut Desert. The relationship between cyanobacterial distribution and environmental factors was also explored. A total of 24,973 cyanobacteria partial 16S rRNA gene sequences were obtained, and 507OTUs were selected, as most OTUs had very few reads. Among these, 347 OTU sequences were of cyanobacteria origin, belonging to Oscillatoriales, Nostocales, Chroococcales, and uncultured cyanobacterium clone, respectively. Microcoleus vaginatus, Chroococcidiopsis spp. and M. steenstrupii were the dominant species in most areas of the Gurbantunggut Desert. Compared with other desert, the Gurbantunggut Desert differed in the prominence of Chroococcidiopsis spp. and lack of Pseudanabaenales. Species composition and abundance of cyanobacteria also showed distinct variations. Soil texture, precipitation, and nutrients and salt levels affected cyanobacterial distribution. Increased precipitation was helpful in improving cyanobacterial diversity. A higher content of coarse sand promoted the colonization and growth of Oscillatoriales and some phylotypes of Chroococcales. The fine-textured soil with higher nutrients and salts supported more varied populations of cyanobacteria, namely some heterocystous cyanobacteria. The results suggested that the Gurbantunggut Desert was rich in cyanobacteria and that precipitation was a primary regulating factor for cyanobacterial composition on a regional scale.

  19. Grain trapping by filamentous cyanobacterial and algal mats: implications for stromatolite microfabrics through time.

    PubMed

    Frantz, C M; Petryshyn, V A; Corsetti, F A

    2015-09-01

    Archean and Proterozoic stromatolites are sparry or fine-grained and finely laminated; coarse-grained stromatolites, such as many found in modern marine systems, do not appear until quite late in the fossil record. The cause of this textural change and its relevance to understanding the evolutionary history of stromatolites is unclear. Cyanobacteria are typically considered the dominant stromatolite builders through time, but studies demonstrating the trapping and binding abilities of cyanobacterial mats are limited. With this in mind, we conducted experiments to test the grain trapping and binding capabilities of filamentous cyanobacterial mats and trapping in larger filamentous algal mats in order to better understand grain size trends in stromatolites. Mats were cut into squares, inclined in saltwater tanks at angles from 0 to 75° (approximating the angle of lamina in typical stromatolites), and grains of various sizes (fine sand, coarse sand, and fine pebbles) were delivered to their surface. Trapping of grains by the cyanobacterial mats depended strongly on (i) how far filaments protruded from the sediment surface, (ii) grain size, and (iii) the mat's incline angle. The cyanobacterial mats were much more effective at trapping fine grains beyond the abiotic slide angle than larger grains. In addition, the cyanobacterial mats actively bound grains of all sizes over time. In contrast, the much larger algal mats trapped medium and coarse grains at all angles. Our experiments suggest that (i) the presence of detrital grains beyond the abiotic slide angle can be considered a biosignature in ancient stromatolites where biogenicity is in question, and, (ii) where coarse grains are present within stromatolite laminae at angles beyond the abiotic angle of slide (e.g., most modern marine stromatolites), typical cyanobacterial-type mats are probably not solely responsible for the construction, giving insight into the evolution of stromatolite microfabrics through time.

  20. Stoichiometric regulation of phytoplankton toxins.

    PubMed

    Van de Waal, Dedmer B; Smith, Val H; Declerck, Steven A J; Stam, Eva C M; Elser, James J

    2014-06-01

    Ecological Stoichiometry theory predicts that the production, elemental structure and cellular content of biomolecules should depend on the relative availability of resources and the elemental composition of their producer organism. We review the extent to which carbon- and nitrogen-rich phytoplankton toxins are regulated by nutrient limitation and cellular stoichiometry. Consistent with theory, we show that nitrogen limitation causes a reduction in the cellular quota of nitrogen-rich toxins, while phosphorus limitation causes an increase in the most nitrogen-rich paralytic shellfish poisoning toxin. In addition, we show that the cellular content of nitrogen-rich toxins increases with increasing cellular N : P ratios. Also consistent with theory, limitation by either nitrogen or phosphorus promotes the C-rich toxin cell quota or toxicity of phytoplankton cells. These observed relationships may assist in predicting and managing toxin-producing phytoplankton blooms. Such a stoichiometric regulation of toxins is likely not restricted to phytoplankton, and may well apply to carbon- and nitrogen-rich secondary metabolites produced by bacteria, fungi and plants.

  1. Food toxin detection with atomic force microscope

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Externally introduced toxins or internal spoilage correlated pathogens and their metabolites are all potential sources of food toxins. To prevent and protect unsafe food, many food toxin detection techniques have been developed to detect various toxins for quality control. Although several routine m...

  2. Detecting and discriminating among Shiga toxins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The virulence associated with Shiga toxin producing Escherichia coli (STEC) infections is from the Shiga toxins produced by the E. coli strain. Although Shiga toxins are associated with E. coli, the expression of the toxins is actually controlled by a temperate lambdoid phage that infects the host. ...

  3. Novel Structure and Function of Typhoid Toxin

    MedlinePlus

    ... toxin, it caused symptoms similar to those in humans with typhoid fever, implicating typhoid toxin in the illness caused by S. typhi. Typhoid toxin can bind to a wide variety of cells. Experiments revealed that the toxin attaches to certain types ...

  4. Local nutrient regimes determine site-specific environmental triggers of cyanobacterial and microcystin variability in urban lakes

    NASA Astrophysics Data System (ADS)

    Sinang, S. C.; Reichwaldt, E. S.; Ghadouani, A.

    2015-05-01

    Toxic cyanobacterial blooms in urban lakes present serious health hazards to humans and animals and require effective management strategies. Managing such blooms requires a sufficient understanding of the controlling environmental factors. A range of them has been proposed in the literature as potential triggers for cyanobacterial biomass development and cyanotoxin (e.g. microcystin) production in freshwater systems. However, the environmental triggers of cyanobacteria and microcystin variability remain a subject of debate due to contrasting findings. This issue has raised the question of whether the relevance of environmental triggers may depend on site-specific combinations of environmental factors. In this study, we investigated the site-specificity of environmental triggers for cyanobacterial bloom and microcystin dynamics in three urban lakes in Western Australia. Our study suggests that cyanobacterial biomass, cyanobacterial dominance and cyanobacterial microcystin content variability were significantly correlated to phosphorus and iron concentrations. However, the correlations were different between lakes, thus suggesting a site-specific effect of these environmental factors. The discrepancies in the correlations could be explained by differences in local nutrient concentration. For instance, we found no correlation between cyanobacterial fraction and total phosphorous (TP) in the lake with the highest TP concentration, while correlations were significant and negative in the other two lakes. In addition, our study indicates that the difference of the correlation between total iron (TFe) and the cyanobacterial fraction between lakes might have been a consequence of differences in the cyanobacterial community structure, specifically the presence or absence of nitrogen-fixing species. In conclusion, our study suggests that identification of significant environmental factors under site-specific conditions is an important strategy to enhance successful outcomes

  5. Comparative Transcriptome Analysis of a Toxin-Producing Dinoflagellate Alexandrium catenella and Its Non-Toxic Mutant

    PubMed Central

    Zhang, Yong; Zhang, Shu-Fei; Lin, Lin; Wang, Da-Zhi

    2014-01-01

    The dinoflagellates and cyanobacteria are two major kingdoms of life producing paralytic shellfish toxins (PSTs), a large group of neurotoxic alkaloids causing paralytic shellfish poisonings around the world. In contrast to the well elucidated PST biosynthetic genes in cyanobacteria, little is known about the dinoflagellates. This study compared transcriptome profiles of a toxin-producing dinoflagellate, Alexandrium catenella (ACHK-T), and its non-toxic mutant form (ACHK-NT) using RNA-seq. All clean reads were assembled de novo into a total of 113,674 unigenes, and 66,812 unigenes were annotated in the known databases. Out of them, 35 genes were found to express differentially between the two strains. The up-regulated genes in ACHK-NT were involved in photosynthesis, carbon fixation and amino acid metabolism processes, indicating that more carbon and energy were utilized for cell growth. Among the down-regulated genes, expression of a unigene assigned to the long isoform of sxtA, the initiator of toxin biosynthesis in cyanobacteria, was significantly depressed, suggesting that this long transcript of sxtA might be directly involved in toxin biosynthesis and its depression resulted in the loss of the ability to synthesize PSTs in ACHK-NT. In addition, 101 putative homologs of 12 cyanobacterial sxt genes were identified, and the sxtO and sxtZ genes were identified in dinoflagellates for the first time. The findings of this study should shed light on the biosynthesis of PSTs in the dinoflagellates. PMID:25421324

  6. Epsilon toxin: a fascinating pore-forming toxin.

    PubMed

    Popoff, Michel R

    2011-12-01

    Epsilon toxin (ETX) is produced by strains of Clostridium perfringens classified as type B or type D. ETX belongs to the heptameric β-pore-forming toxins including aerolysin and Clostridium septicum alpha toxin, which are characterized by the formation of a pore through the plasma membrane of eukaryotic cells consisting in a β-barrel of 14 amphipatic β strands. By contrast to aerolysin and C. septicum alpha toxin, ETX is a much more potent toxin and is responsible for enterotoxemia in animals, mainly sheep. ETX induces perivascular edema in various tissues and accumulates in particular in the kidneys and brain, where it causes edema and necrotic lesions. ETX is able to pass through the blood-brain barrier and stimulate the release of glutamate, which accounts for the symptoms of nervous excitation observed in animal enterotoxemia. At the cellular level, ETX causes rapid swelling followed by cell death involving necrosis. The precise mode of action of ETX remains to be determined. ETX is a powerful toxin, however, it also represents a unique tool with which to vehicle drugs into the central nervous system or target glutamatergic neurons.

  7. Botulinum toxin in clinical practice

    PubMed Central

    Jankovic, J

    2004-01-01

    Botulinum toxin, the most potent biological toxin, has become a powerful therapeutic tool for a growing number of clinical applications. This review draws attention to new findings about the mechanism of action of botulinum toxin and briefly reviews some of its most frequent uses, focusing on evidence based data. Double blind, placebo controlled studies, as well as open label clinical trials, provide evidence that, when appropriate targets and doses are selected, botulinum toxin temporarily ameliorates disorders associated with excessive muscle contraction or autonomic dysfunction. When injected not more often than every three months, the risk of blocking antibodies is slight. Long term experience with this agent suggests that it is an effective and safe treatment not only for approved indications but also for an increasing number of off-label indications. PMID:15201348

  8. [Biological and toxin terrorism weapons].

    PubMed

    Bokan, Slavko

    2003-03-01

    The use of biological agents and toxins in warfare and terrorism has a long history. Human, animal and plant pathogens and toxins can cause disease and can be used as a threat to humans, animals and staple crops. The same is true for biological agents. Although the use of biological agents and toxins in military conflicts has been a concern of military communities for many years, several recent events have increased the awareness of terrorist use of these weapons against civilian population. A Mass Casualty Biological (Toxin) Weapon (MCBTW) is any biological and toxin weapon capable of causing death or disease on a large scale, such that the military or civilian infrastructure of the state or organization being attacked is overwhelmed. A militarily significant (or terrorist) weapon is any weapon capable of affecting, directly or indirectly, that is physically or psychologically, the outcome of a military operation. Although many biological agents such as toxins and bioregulators can be used to cause diseases, there are only a few that can truly threaten civilian populations on a large scale. Bioregulators or modulators are biochemical compounds, such as peptides, that occur naturally in organisms. They are new class of weapons that can damage nervous system, alter moods, trigger psychological changes and kill. The potential military or terrorist use of bioregulators is similar to that of toxins. Some of these compounds are several hundred times more potent than traditional chemical warfare agents. Important features and military advantages of new bioregulators are novel sites of toxic action; rapid and specific effects; penetration of protective filters and equipment, and militarily effective physical incapacitation. This overview of biological agents and toxins is largely intended to help healthcare providers on all levels to make decisions in protecting general population from these agents.

  9. A green-light inducible lytic system for cyanobacterial cells

    PubMed Central

    2014-01-01

    Background Cyanobacteria are an attractive candidate for the production of biofuel because of their ability to capture carbon dioxide by photosynthesis and grow on non-arable land. However, because huge quantities of water are required for cultivation, strict water management is one of the greatest issues in algae- and cyanobacteria-based biofuel production. In this study, we aim to construct a lytic cyanobacterium that can be regulated by a physical signal (green-light illumination) for future use in the recovery of biofuel related compounds. Results We introduced T4 bacteriophage-derived lysis genes encoding holin and endolysin under the control of the green-light regulated cpcG2 promoter in Synechocystis sp. PCC 6803. When cells harboring the lysis genes were illuminated with both red and green light, we observed a considerable decrease in growth rate, a significant increase in cellular phycocyanin released in the medium, and a considerable fraction of dead cells. These effects were not observed when these cells were illuminated with only red light, or when cells not containing the lysis genes were grown under either red light or red and green light. These results indicate that our constructed green-light inducible lytic system was clearly induced by green-light illumination, resulting in lytic cells that released intracellular phycocyanin into the culture supernatant. This property suggests a future possibility to construct photosynthetic genetically modified organisms that are unable to survive under sunlight exposure. Expression of the self-lysis system with green-light illumination was also found to greatly increase the fragility of the cell membrane, as determined by subjecting the induced cells to detergent, osmotic-shock, and freeze-thaw treatments. Conclusions A green-light inducible lytic system was constructed in Synechocystis sp. PCC 6803. The engineered lytic cyanobacterial cells should be beneficial for the recovery of biofuels and related compounds

  10. Flow-induced Development of Unicellular Cyanobacterial Mats

    NASA Astrophysics Data System (ADS)

    Gong, J.; Tice, M. M.

    2011-12-01

    Microbial mats/biofilms are abundant microbial growth structures throughout the history of life on Earth. Understanding the mechanisms for their morphogenesis and interactions with physical sedimentary forces are important topics that allow deeper understanding of related records. When subjected to hydrodynamic influences, mats are known to vary in morphology and structure in response to fluid shear, yet mechanistically, the underlying cellular architecture due to interactions with flow remain unexplained. Moreover, mats are found to emerge larger scale roughness elements and modified cohesive strength growing under flow. It is a mystery how and why these mat-community-level features are linked in association with modified boundary layers at the mats surface. We examined unicellular cyanobacterium Synechocystis sp. PCC 6803 in a circular flow bioreactor designed to maintain a fixed set of hydrodynamic conditions. The use of monoculture strains and unidirectional currents, while not replicating natural mat systems (almost certainly multi-species and often multi-directional currents under complex wind or tidal wave actions), helps to simplify these systems and allows for specific testing of hypotheses regarding how mats evolve distinctive morphologies induced by flow. The unique design of the reactor also makes measurements such as critical erosional shear stress of the mats possible, in addition to microscopic, macroscopic imaging and weeks of continuous mats growth monitoring. We report the finding that linear chains, filament-like cell groups were present from unicellular cyanobacterial mats growing under flow (~1-5 cm/s) and these structures are organized within ~1-3mm size streamers and ~0.5-1mm size nodular macrostructures. Ultra-small, sub-micron thick EPS strings are observed under TEM and are likely the cohesive architectural elements in mats across different fluid regimes. Mat cohesion generally grows with and adapts to increasing flow shear stress within

  11. Cyanobacterial construction of hot spring siliceous stromatolites in Yellowstone National Park.

    PubMed

    Pepe-Ranney, Charles; Berelson, William M; Corsetti, Frank A; Treants, Merika; Spear, John R

    2012-05-01

    Living stromatolites growing in a hot spring in Yellowstone National Park are composed of silica-encrusted cyanobacterial mats. Two cyanobacterial mat types grow on the stromatolite surfaces and are preserved as two distinct lithofacies. One mat is present when the stromatolites are submerged or at the water-atmosphere interface and the other when stromatolites protrude from the hot spring. The lithofacies created by the encrustation of submerged mats constitutes the bulk of the stromatolites, is comprised of silica-encrusted filaments, and is distinctly laminated. To better understand the cyanobacterial membership and community structure differences between the mats, we collected mat samples from each type. Molecular methods revealed that submerged mat cyanobacteria were predominantly one novel phylotype while the exposed mats were predominantly heterocystous phylotypes (Chlorogloeopsis HTF and Fischerella). The cyanobacterium dominating the submerged mat type does not belong in any of the subphylum groups of cyanobacteria recognized by the Ribosomal Database Project and has also been found in association with travertine stromatolites in a Southwest Japan hot spring. Cyanobacterial membership profiles indicate that the heterocystous phylotypes are 'rare biosphere' members of the submerged mats. The heterocystous phylotypes likely emerge when the water level of the hot spring drops. Environmental pressures tied to water level such as sulfide exposure and possibly oxygen tension may inhibit the heterocystous types in submerged mats. These living stromatolites are finely laminated and therefore, in texture, may better represent similarly laminated ancient forms compared with more coarsely laminated living marine examples.

  12. Estimating genetic structure and diversity of cyanobacterial communities in Atlantic forest phyllosphere.

    PubMed

    Rigonato, Janaina; Gonçalves, Natalia; Andreote, Ana Paula Dini; Lambais, Marcio Rodrigues; Fiore, Marli Fátima

    2016-06-20

    Cyanobacterial communities on the phyllosphere of 4 plant species inhabiting the endangered Brazilian Atlantic Forest biome were evaluated using cultivation-independent molecular approaches. Total genomic DNA was extracted from cells detached from the surface of leaves of Euterpe edulis, Guapira opposita, Garcinia gardneriana, and Merostachys neesii sampled in 2 Brazilian Atlantic Forest locations along an elevational gradient, i.e., lowland and montane forest. The DNA fingerprinting method PCR-DGGE revealed that the cyanobacterial phyllosphere community structures were mainly influenced by the plant species; geographical location of the plant had little effect. The 16S rRNA gene sequences obtained by clone libraries showed a predominance of nitrogen-fixing cyanobacteria of the order Nostocales, even though the majority of retrieved operational taxonomic units (∼60% of the sequences) showed similarity only to uncultured cyanobacteria phylotypes. The leaf surface of Guapira opposita had the highest richness and diversity of cyanobacteria, whereas the M. neesii (bamboo) had the largest number of copies of cyanobacterial 16S rRNA gene per cm(2) of leaf. This study investigated cyanobacteria diversity and its distribution pattern in Atlantic forest phyllosphere. The results indicated that plant species is the main driver of cyanobacteria community assemblage in the phyllosphere and that these communities are made up of a high diversity of cyanobacterial taxa that need to be discovered.

  13. Quantifying cyanobacterial phycocyanin concentration in turbid productive waters: a quasi-analytical approach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this research, we present a novel technique to monitor cyanobacterial algal bloom using remote sensing measurements. We have used a multi-band quasi analytical algorithm that determines phytoplankton absorption coefficients, aF('), from above-surface remote sensing reflectance, Rrs('). In situ da...

  14. Cyanobacterial harmful algal blooms are a biological disturbance to Western Lake Erie bacterial communities.

    PubMed

    Berry, Michelle A; Davis, Timothy W; Cory, Rose M; Duhaime, Melissa B; Johengen, Thomas H; Kling, George W; Marino, John A; Den Uyl, Paul A; Gossiaux, Duane; Dick, Gregory J; Denef, Vincent J

    2017-03-01

    Human activities are causing a global proliferation of cyanobacterial harmful algal blooms (CHABs), yet we have limited understanding of how these events affect freshwater bacterial communities. Using weekly data from western Lake Erie in 2014, we investigated how the cyanobacterial community varied over space and time, and whether the bloom affected non-cyanobacterial (nc-bacterial) diversity and composition. Cyanobacterial community composition fluctuated dynamically during the bloom, but was dominated by Microcystis and Synechococcus OTUs. The bloom's progression revealed potential impacts to nc-bacterial diversity. Nc-bacterial evenness displayed linear, unimodal, or no response to algal pigment levels, depending on the taxonomic group. In addition, the bloom coincided with a large shift in nc-bacterial community composition. These shifts could be partitioned into components predicted by pH, chlorophyll a, temperature, and water mass movements. Actinobacteria OTUs showed particularly strong correlations to bloom dynamics. AcI-C OTUs became more abundant, while acI-A and acI-B OTUs declined during the bloom, providing evidence of niche partitioning at the sub-clade level. Thus, our observations in western Lake Erie support a link between CHABs and disturbances to bacterial community diversity and composition. Additionally, the short recovery of many taxa after the bloom indicates that bacterial communities may exhibit resilience to CHABs.

  15. Cyanobacterial Community Structure In Lithifying Mats of A Yellowstone Hotspring-Implications for Precambrian Stromatolite Biocomplexity

    NASA Technical Reports Server (NTRS)

    Lau, Evan; Nash, C. Z.; Vogler, D. R.; Cullings, K.; DeVincenzi, Donald (Technical Monitor)

    2002-01-01

    Denaturing Gradient Gel Electrophoresis (DGGE) of partial 16S rRNA gene sequences was used to investigate the molecular biodiversity of cyanobacterial communities inhabiting various lithified morpho-structures in two hotsprings of Yellowstone National Park. These morpho-structures - flat-topped columns, columnar cones, and ridged cones - resemble ancient stromatolites, which are possibly biogenic in origin. The top, middle and bottom sections of these lithified morpho-structures, as well as surrounding non-lithified mats were analyzed to determine the vertical and spatial distribution of cyanobacterial communities. Results from DGGE indicate that the cyanobacterial community composition of lithified morpho-structures (flat-topped columns, columnar cones, and ridged cones) were largely similar in vertical distribution as well as among the morpho-structures being studied. Preliminary results indicate that the cyanobacterial communities in these lithified morpho-structures were significantly different from communities in surrounding non-lithified mats. These results provide additional support to the theory that certain Phormidium/Leptolyngbya species are involved in the morphogenesis of lithifying morpho-structures in hotsprings and may have played a role in the formation of ancient stromatolites.

  16. Cyanobacterial diversity of western European biological soil crusts along a latitudinal gradient

    PubMed Central

    Williams, Laura; Loewen-Schneider, Katharina; Maier, Stefanie; Büdel, Burkhard

    2016-01-01

    Cyanobacteria associated with biological soil crusts (BSCs) have important attributes, such as nitrogen fixation and soil stabilisation. However, research on these organisms has been minimal, and their diversity and distribution throughout temperate Europe is currently unknown. The SCIN (Soil Crust International) project is a multidisciplinary research initiative that aims to achieve improved understanding of the BSCs of Europe, one facet being an investigation into the cyanobacterial communities of BSCs across a latitudinal gradient. Cyanobacteria assemblages were analysed by both morphological and molecular analysis. Two treatments were applied prior to DNA extraction, continued sample wetting and a dry sample process, and 16S ribosomal RNA (rRNA) amplicons were processed by Illumina MiSeq sequencing. The results reveal high and variable cyanobacterial diversity with each site showing a unique assemblage. Many common cyanobacterial genera, for example Nostoc and Microcoleus, were found in all sites but the abundances of different genera varied considerably. The polyphasic approach was found to be essential in recording the presence of important cyanobacteria that a single method itself did not highlight. The wet and dry treatments showed some differences in diversity, but mainly in abundance, this may suggest how cyanobacterial composition of BSCs changes with seasonal variability. PMID:27411981

  17. Global metabolome changes induced by cyanobacterial blooms in three representative fish species.

    PubMed

    Sotton, Benoît; Paris, Alain; Le Manach, Séverine; Blond, Alain; Lacroix, Gérard; Millot, Alexis; Duval, Charlotte; Qiao, Qin; Catherine, Arnaud; Marie, Benjamin

    2017-07-15

    Cyanobacterial blooms induce important ecological constraints for aquatic organisms and strongly impact the functioning of aquatic ecosystems. In the past decades, the effects of the cyanobacterial secondary metabolites, so called cyanotoxins, have been extensively studied in fish. However, many of these studies have used targeted approaches on specific molecules, which are thought to react to the presence of these specific cyanobacterial compounds. Since a few years, untargeted metabolomic approaches provide a unique opportunity to evaluate the global response of hundreds of metabolites at a glance. In this way, our study provides the first utilization of metabolomic analyses in order to identify the response of fish exposed to bloom-forming cyanobacteria. Three relevant fish species of peri-urban lakes of the European temperate regions were exposed for 96h either to a microcystin (MC)-producing or to a non-MC-producing strain of Microcystis aeruginosa and metabolome changes were characterized in the liver of fish. The results suggest that a short-term exposure to those cyanobacterial biomasses induces metabolome changes without any response specificity linked to the fish species considered. Candidate metabolites are involved in energy metabolism and antioxidative response, which could potentially traduce a stress response of fish submitted to cyanobacteria. These results are in agreement with the already known information and could additionally bring new insights about the molecular interactions between cyanobacteria and fish.

  18. Cyanobacterial diversity across landscape units in a polar desert: Taylor Valley, Antarctica.

    PubMed

    Michaud, Alexander B; Šabacká, Marie; Priscu, John C

    2012-11-01

    Life in the Taylor Valley, Antarctica, is dominated by microorganisms, with cyanobacteria being key primary producers in the region. Despite their abundance and ecological importance, the factors controlling biogeography, diversity, dispersal of cyanobacteria in Taylor Valley and other polar environments are poorly understood. Owing to persistent high winds, we hypothesize that the cyanobacterial diversity across this polar landscape is influenced by aeolian processes. Using molecular and pigment analysis, we describe the cyanobacterial diversity present in several prominent habitats across the Taylor Valley. Our data show that the diversity of cyanobacteria increases from the upper portion of the valley towards the McMurdo Sound. This trend is likely due to the net transport of organisms in a down-valley direction, consistent with the prevailing orientation of high-energy, episodic föhn winds. Genomic analysis of cyanobacteria present in aeolian material also suggests that wind mixes the cyanobacterial phylotypes among the landscape units. Our 16S rRNA gene sequence data revealed that (1) many of the cyanobacterial phylotypes present in our study site are common in polar or alpine environments, (2) many operational taxonomic units (OTUs) (22) were endemic to Antarctica and (3) four OTUs were potentially endemic to the McMurdo Dry Valleys.

  19. Genetic tools for advancement of Synechococcus sp. PCC 7002 as a cyanobacterial chassis

    DOE PAGES

    Ruffing, Anne M.; Jensen, Travis J.; Strickland, Lucas M.

    2016-11-10

    Successful implementation of modified cyanobacteria as hosts for industrial applications requires the development of a cyanobacterial chassis. The cyanobacterium Synechococcus sp. PCC 7002 embodies key attributes for an industrial host, including a fast growth rate and high salt, light, and temperature tolerances. Here, this study addresses key limitations in the advancement of Synechococcus sp. PCC 7002 as an industrial chassis.

  20. Visually assessing the level of development and soil surface stability of cyanobacterially dominated biological soil crusts

    USGS Publications Warehouse

    Belnap, J.; Phillips, S.L.; Witwicki, D.L.; Miller, M.E.

    2008-01-01

    Biological soil crusts (BSCs) are an integral part of dryland ecosystems and often included in long-term ecological monitoring programs. Estimating moss and lichen cover is fairly easy and non-destructive, but documenting cyanobacterial level of development (LOD) is more difficult. It requires sample collection for laboratory analysis, which causes soil surface disturbance. Assessing soil surface stability also requires surface disturbance. Here we present a visual technique to assess cyanobacterial LOD and soil surface stability. We define six development levels of cyanobacterially dominated soils based on soil surface darkness. We sampled chlorophyll a concentrations (the most common way of assessing cyanobacterial biomass), exopolysaccharide concentrations, and soil surface aggregate stability from representative areas of each LOD class. We found that, in the laboratory and field, LOD classes were effective at predicting chlorophyll a soil concentrations (R2=68-81%), exopolysaccharide concentrations (R2=71%), and soil aggregate stability (R2=77%). We took representative photos of these classes to construct a field guide. We then tested the ability of field crews to distinguish these classes and found this technique was highly repeatable among observers. We also discuss how to adjust this index for the different types of BSCs found in various dryland regions.

  1. Mining Metatranscriptomic Data of a Cyanobacterial Bloom for Patterns of Secondary Metabolism Gene Expression

    NASA Astrophysics Data System (ADS)

    Penn, K.; Wang, J.; Thompson, J. R.

    2012-12-01

    The secondary metabolism of bacterial cells produces small molecules that can have both medicinal properties and toxigenic effects. This study focuses on mining metatranscriptomes from a tropical eutrophic water reservoir in Singapore experiencing a cyanobacterial Harmful Algal Bloom dominated by Microcystis, to identify the types of secondary metabolites genes being expressed and by what taxa. A phylogenomic approach as implemented in the online tool Natural Product Domain Seeker (NaPDoS) was used. NaPDoS was recently developed to classify ketosynthase and condensation domains from polyketide synthases and non-ribosomal peptide synthetases, respectively, to provide insight into potential types of pathway products. Water samples from the reservoir were collected six times over a day/night cycle. Total RNA was extracted and subjected to ribosomal depletion followed by cDNA synthesis and next-generation Illumina DNA sequencing, generating 493,468 to 678,064 95-101 base pairs post-quality control reads per sample. Evidence for expression of PKS and NRPS type genes based on identification of a ketosynthase and condensation domains are present in all time points. KS domains fall into to two main phylogenetic groups, type I and type II, within the type II group of domains are domains for fatty acid biosynthesis (fab), which is considered a part of primary metabolism. Type I KS domains are part of the classic PKS natural product biosynthetic genes that make things such as antibiotics and other toxins such as microcystin. 2849 KS domains were detected in the combined reservoir samples, of these 1141 were likely from fatty acid biosynthesis and 1708 were related to secondary metabolism type KS domains. The most abundant KS domains (485) besides the fab genes are closely related to a KS domain that is not currently experimentally linked to a known secondary metabolite but the domain is found in four Microcystis genomes along with two other species of cyanobacteria. The three

  2. Hydrogen from Water in a Novel Recombinant Cyanobacterial System

    SciTech Connect

    Weyman, Philip D; Smith, Hamillton O.

    2014-12-03

    Photobiological processes are attractive routes to renewable H2 production. With the input of solar energy, photosynthetic microbes such as cyanobacteria and green algae carry out oxygenic photosynthesis, using sunlight energy to extract protons and high energy electrons from water. These protons and high energy electrons can be fed to a hydrogenase system yielding H2. However, most hydrogen-evolving hydrogenases are inhibited by O2, which is an inherent byproduct of oxygenic photosynthesis. The rate of H2 production is thus limited. Certain photosynthetic bacteria are reported to have an O2-tolerant evolving hydrogenase, yet these microbes do not split water, and require other more expensive feedstocks. To overcome these difficulties, the goal of this work has been to construct novel microbial hybrids by genetically transferring O2-tolerant hydrogenases from other bacteria into a class of photosynthetic bacteria called cyanobacteria. These hybrid organisms will use the photosynthetic machinery of the cyanobacterial hosts to perform the water-oxidation reaction with the input of solar energy, and couple the resulting protons and high energy electrons to the O2-tolerant bacterial hydrogenase, all within the same microbe (Fig. 1). The ultimate goal of this work has been to overcome the sensitivity of the hydrogenase enzyme to O2 and address one of the key technological hurdles to cost-effective photobiological H2 production which currently limits the production of hydrogen in algal systems. In pursuit of this goal, work on this project has successfully completed many subtasks leading to a greatly increased understanding of the complicated [NiFe]-hydrogenase enzymes. At the beginning of this project, [NiFe] hydrogenases had never been successfully moved across wide species barriers and had never been heterologously expressed in cyanobacteria. Furthermore, the idea that whole, functional genes could be extracted from complicated, mixed-sequence meta-genomes was not

  3. The calcium carbonate saturation state in cyanobacterial mats throughout Earth’s history

    NASA Astrophysics Data System (ADS)

    Aloisi, Giovanni

    2008-12-01

    Through early lithification, cyanobacterial mats produced vast amounts of CaCO 3 on Precambrian carbonate platforms (before 540 Myr ago). The superposition of lithified cyanobacterial mats forms internally laminated, macroscopic structures known as stromatolites. Similar structures can be important constituents of Phanerozoic carbonate platforms (540 Myr to present). Early lithification in modern marine cyanobacterial mats is thought to be driven by a metabolically-induced increase of the CaCO 3 saturation state ( Ω) in the mat. However, it is uncertain which microbial processes produce the Ω increase and to which extent similar Ω shifts were possible in Precambrian oceans whose chemistry differed from that of the modern ocean. I developed a numerical model that calculates Ω in cyanobacterial mats and used it to tackle these questions. The model is first applied to simulate Ω in modern calcifying cyanobacterial mats forming at Highborne Cay (Bahamas); it shows that while cyanobacterial photosynthesis increases Ω considerably, sulphate reduction has a small and opposite effect on mat Ω because it is coupled to H 2S oxidation with O 2 which produces acidity. Numerical experiments show that the magnitude of the Ω increase is proportional to DIC in DIC-limited waters (DIC < 3-10 mM), is proportional to pH when ambient water DIC is not limiting and always proportional to the concentration of Ca 2+ in ambient waters. With oceanic Ca 2+ concentrations greater than a few millimolar, an appreciable increase in Ω occurs in mats under a wide range of environmental conditions, including those supposed to exist in the oceans of the past 2.8 Gyr. The likely lithological expression is the formation of the microsparitic stromatolite microtexture—indicative of CaCO 3 precipitation within the mats under the control of microbial activity—which is found in carbonate rocks spanning from the Precambrian to recent. The model highlights the potential for an increase in the

  4. Antibody-based biological toxin detection

    SciTech Connect

    Menking, D.E.; Goode, M.T.

    1995-12-01

    Fiber optic evanescent fluorosensors are under investigation in our laboratory for the study of drug-receptor interactions for detection of threat agents and antibody-antigen interactions for detection of biological toxins. In a direct competition assay, antibodies against Cholera toxin, Staphylococcus Enterotoxin B or ricin were noncovalently immobilized on quartz fibers and probed with fluorescein isothiocyanate (FITC) - labeled toxins. In the indirect competition assay, Cholera toxin or Botulinum toxoid A was immobilized onto the fiber, followed by incubation in an antiserum or partially purified anti-toxin IgG. These were then probed with FITC-anti-IgG antibodies. Unlabeled toxins competed with labeled toxins or anti-toxin IgG in a dose dependent manner and the detection of the toxins was in the nanomolar range.

  5. Monitoring levels of cyanobacterial blooms using the visual cyanobacteria index (VCI) and floating algae index (FAI)

    NASA Astrophysics Data System (ADS)

    Oyama, Yoichi; Fukushima, Takehiko; Matsushita, Bunkei; Matsuzaki, Hana; Kamiya, Koichi; Kobinata, Hisao

    2015-06-01

    Cyanobacterial bloom is a growing environmental problem in inland waters. In this study, we propose a method for monitoring levels of cyanobacterial blooms from Landsat/ETM+ images. The visual cyanobacteria index (VCI) is a simple index for in-situ visual interpretation of cyanobacterial blooms levels, by classifying them into six categories based on aggregation (e.g., subsurface blooms, surface scum). The floating algae index (FAI) and remote sensing reflectance in the red wavelength domain, which can be obtained from Landsat/ETM+ images, were related to the VCI for estimating cyanobacteria bloom levels from the Landsat/ETM+ images. Nine field campaigns were carried out at Lakes Nishiura and Kitaura (Lake Kasumigaura group), Japan, from June to August 2012. We also collected reflectance spectra at 20 stations for different VCI levels on August 3, 2012. The reflectance spectra were recalculated in correspondence to each ETM+ band, and used to calculate the FAI. The FAI values were then used to determine thresholds for classifying cyanobacterial blooms into different VCI levels. These FAI thresholds were validated using three Landsat/ETM+ images. Results showed that FAI values differed significantly at the respective VCI levels except between levels 1 and 2 (subsurface blooms) and levels 5 and 6 (surface scum and hyperscum). This indicated that the FAI was able to detect the high level of cyanobacteria that forms surface scum. In contrast, the Landsat/ETM+ band 3 reflectance could be used as an alternative index for distinguishing surface scum and hyperscum. Application of the thresholds for VCI classifications to three Landsat/ETM+ images showed that the volume of cyanobacterial blooms can be effectively classified into the six VCI levels.

  6. Physiological interaction of Daphnia and Microcystis with regard to cyanobacterial secondary metabolites.

    PubMed

    Sadler, Thomas; von Elert, Eric

    2014-11-01

    Cyanobacterial blooms in freshwater ecosystems are a matter of high concern with respect to human health and ecosystem services. Investigations on the role of cyanobacterial secondary metabolites have largely been confined to microcystins, although cyanobacteria produce a huge variety of toxic or inhibitory secondary metabolites. Mass occurrences of toxic cyanobacteria strongly impact freshwater zooplankton communities; especially the unselective filter feeder Daphnia. Daphnids have been shown to successfully suppress bloom formation. However, the opposite situation, i.e. the suppression of Daphnia populations by cyanobacteria can be observed as well. To understand these contradictory findings the elucidation of the underlying physiological mechanisms that help daphnids to cope with cyanotoxins is crucial. We fed Daphnia magna with the cyanobacterium Microcystis aeruginosa PCC7806 for 24h and used high-resolution LCMS analytics to analyze the Microcystis cells, the Daphnia tissue and the surrounding medium in order to investigate the fate of seven investigated cyanobacterial compounds (cyanopeptolins A-C, microcyclamide 7806A and aerucyclamides B-D). For none of these bioactive compounds evidence for biotransformation or biodegradation by Daphnia were found. Instead feeding and subsequent release experiments point at the importance of transport mechanisms in Daphnia with regard to the cyanopeptolins A and C and microcyclamide 7806A. In addition we found hints for new inducible defense mechanism in Microcystis against predation by Daphnia. These putative defense mechanisms include the elevated production of toxic compounds other than microcystins, as could be demonstrated here for aerucyclamide B and D, cyanopoeptolin B and microcyclamide 7806A. Moreover, our data demonstrate the elevated active export of at least one cyanobacterial compound (microcyclamide 7806A) into the surrounding medium as a response to grazer presence, which might constitute an entirely new

  7. Temporal variation in community composition, pigmentation, and Fv/Fm of desert cyanobacterial soil crusts

    USGS Publications Warehouse

    Bowker, M.A.; Reed, S.C.; Belnap, J.; Phillips, S.L.

    2002-01-01

    Summers on the Colorado Plateau (USA) are typified by harsh conditions such as high temperatures, brief soil hydration periods, and high UV and visible radiation. We investigated whether community composition, physiological status, and pigmentation might vary in biological soil crusts as a result of such conditions. Representative surface cores were sampled at the ENE, WSW, and top microaspects of 20 individual soil crust pedicels at a single site in Canyonlands National Park, Utah, in spring and fall of 1999. Frequency of cyanobacterial taxa, pigment concentrations, and dark adapted quantum yield (Fv/Fm) were measured for each core. The frequency of major cyanobacterial taxa was lower in the fall compared to spring. The less-pigmented cyanobacterium Microcoleus vaginatus showed significant mortality when not in the presence of Nostoc spp. and Scytonema myochrous (Dillw.) Agardh. (both synthesizers of UV radiation-linked pigments) but had little or no mortality when these species were abundant. We hypothesize that the sunscreen pigments produced by Nostoc and Scytonema in the surface of crusts protect other, less-pigmented taxa. When fall and spring samples were compared, overall cyanobacterial frequency was lower in fall, while sunscreen pigment concentrations, chlorophyll a concentration, and Fv/Fm were higher in fall. The ratio of cyanobacterial frequency/chlorophyll a concentrations was 2-3 times lower in fall than spring. Because chlorophyll a is commonly used as a surrogate measure of soil cyanobacterial biomass, these results indicate that seasonality needs to be taken into consideration. In the fall sample, most pigments associated with UV radiation protection or repair were at their highest concentrations on pedicel tops and WSW microaspects, and at their lowest concentrations on ENE microaspects. We suggest that differential pigment concentrations between microaspects are induced by varying UV radiation dosage at the soil surface on these different

  8. Contributions of meteorology to the phenology of cyanobacterial blooms: implications for future climate change.

    PubMed

    Zhang, Min; Duan, Hongtao; Shi, Xiaoli; Yu, Yang; Kong, Fanxiang

    2012-02-01

    Cyanobacterial blooms are often a result of eutrophication. Recently, however, their expansion has also been found to be associated with changes in climate. To elucidate the effects of climatic variables on the expansion of cyanobacterial blooms in Taihu, China, we analyzed the relationships between climatic variables and bloom events which were retrieved by satellite images. We then assessed the contribution of each climate variable to the phenology of blooms using multiple regression models. Our study demonstrates that retrieving ecological information from satellite images is meritorious for large-scale and long-term ecological research in freshwater ecosystems. Our results show that the phenological changes of blooms at an inter-annual scale are strongly linked to climate in Taihu during the past 23 yr. Cyanobacterial blooms occur earlier and last longer with the increase of temperature, sunshine hours, and global radiation and the decrease of wind speed. Furthermore, the duration increases when the daily averages of maximum, mean, and minimum temperature each exceed 20.3 °C, 16.7 °C, and 13.7 °C, respectively. Among these factors, sunshine hours and wind speed are the primary contributors to the onset of the blooms, explaining 84.6% of their variability over the past 23 yr. These factors are also good predictors of the variability in the duration of annual blooms and determined 58.9% of the variability in this parameter. Our results indicate that when nutrients are in sufficiently high quantities to sustain the formation of cyanobacterial blooms, climatic variables become crucial in predicting cyanobacterial bloom events. Climate changes should be considered when we evaluate how much the amount of nutrients should be reduced in Taihu for lake management.

  9. Uremic toxins and peritoneal dialysis.

    PubMed

    Lameire, N; Vanholder, R; De Smet, R

    2001-02-01

    Uremic toxicity is related in part to the accumulation of toxic substances, the nature of which has only partly been characterized. Because of the use of a highly permeable membrane and better preservation of the residual renal function, it could be anticipated that some of these uremic toxins are more efficiently cleared across the peritoneal membrane, and that the plasma and tissue levels of these compounds are lower than in hemodialysis patients. This article analyzes the generation and removal of several uremic toxins in peritoneal dialysis patients. The following uremic toxins are discussed: beta2-microglobulin, advanced glycation end products, advanced oxidation protein products, granulocyte inhibitory proteins, p-Cresol, and hyperhomocysteinemia. Some recent studies are reviewed suggesting that uremic toxins are involved in the progression of renal failure and are at least partially removed by peritoneal dialysis. We conclude that, although the plasma levels of some of these compounds are lower in peritoneal dialysis versus hemodialysis patients, it does not mean that the peritoneal dialysis patient is "better" protected against the numerous disturbances caused by these toxins.

  10. Sodium Channel Inhibiting Marine Toxins

    NASA Astrophysics Data System (ADS)

    Llewellyn, Lyndon E.

    Saxitoxin (STX), tetrodotoxin (TTX) and their many chemical relatives are part of our daily lives. From killing people who eat seafood containing these toxins, to being valuable research tools unveiling the invisible structures of their pharmacological receptor, their global impact is beyond measure. The pharmacological receptor for these toxins is the voltage-gated sodium channel which transports Na ions between the exterior to the interior of cells. The two structurally divergent families of STX and TTX analogues bind at the same location on these Na channels to stop the flow of ions. This can affect nerves, muscles and biological senses of most animals. It is through these and other toxins that we have developed much of our fundamental understanding of the Na channel and its part in generating action potentials in excitable cells.

  11. Botulinum Toxin in Migraine Treatment

    PubMed Central

    ILGAZ AYDINLAR, Elif; YALINAY DİKMEN, Pınar; SAĞDUYU KOCAMAN, Ayşe

    2013-01-01

    Since botulinum toxin might have a therapeutic effect on pain, many studies investigating the efficiency of botulinum toxin in headache treatment have been done. The most satisfying results were achieved by botulinum toxin type A (BoNT/A) in the treatment of chronic migraine. In this paper, we reviewed the clinical effectiveness of BoNT/A in migraine and included our clinical experience. In our ongoing pilot study, where we have repeated BoNT/A injections every 12 weeks, The difference in the Migraine Disability Assessment (MIDAS) scores between the first and the second injections was 61.1%; and between the first and the 3rd injections was found to be 65.72%.

  12. Inhibition of cholera toxin and other AB toxins by polyphenolic compounds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    All AB-type protein toxins have intracellular targets despite an initial extracellular location. These toxins use different methods to reach the cytosol and have different effects on the target cell. Broad-spectrum inhibitors against AB toxins are therefore hard to develop because the toxins use dif...

  13. Relation between primary liver cancer occurrence and freshwater Cyanobacterial blooms in Serbia

    NASA Astrophysics Data System (ADS)

    Svirčev, Z.; Miladinov-Mikov, M.; Simeunović, J.; Vidović, M.; Stojanović, D.

    2009-04-01

    Since 1980 cyanobacterial blooms occurred in a large number of reservoirs, lakes and running water ecosystems (rivers and channels) in Serbia. Among 49 reservoirs examined, 32 were found in blooming condition almost every year during last 2 decades. All natural lakes and 12 river and channel localities in Vojvodina province (agricultural part) proved to be sites with cyanobacterial proliferation. The part of Central Serbia is very problematic for ground water supply. For that reason 21 reservoirs serve as drinking water suppliers. Significant and persistant cyanobacterial blooms have been recognized in 9 of them. Samples for cyanotoxin analyses were taken during and after blooms in Celije Reservoir and in drinking water in Krusevac town 2 days later. Concentratins of Microcystin-LR were 460 µg•L-1 and for Microcystin-RR 170 µg•L-1. Drinking water contained 2 and 0.6 µg•L-1, respectively. Serbia consists of 30 administrative units, in three of which studies for Primary Liver Cancer (PLC) were conducted independently: Vojvodina, where drinking-water is supplied only from deep wells where 7 regions were studied, Kosovo with a few high mountain reservoirs for water supply without cyanobacterial proliferation where 6 regions were studied, and Central Serbia, where 17 regions were studied. Central Serbia showed 7 regions with extremly high PLC incidence and 8 regions with lower PLC incidence. In the two investigated periods, the high PLC mortality of 11.6 in 1980-1995 and extremely high PLC incidence of 26 in 2000 was observed in the regions affected by heavy cyanobacterial blooms. In contrast, the regions not affected by the blooms, PLC mortality and incidence rates were substantially lower: from 1980-1995 mortality rate ammounted to 2.7 in Kosovo, 7.6 in Vojvodina, and 8.5 in the non-affected regions of Central Serbia, and in 2000 incidence rate ammounted to 4.1 (Kosovo), 6.6 (Vojvodina), and 7.5 in the non-affected regions of Central Serbia. The uneven

  14. Toxin yet not toxic: Botulinum toxin in dentistry.

    PubMed

    Archana, M S

    2016-04-01

    Paracelsus contrasted poisons from nonpoisons, stating that "All things are poisons, and there is nothing that is harmless; the dose alone decides that something is a poison". Living organisms, such as plants, animals, and microorganisms, constitute a huge source of pharmaceutically useful medicines and toxins. Depending on their source, toxins can be categorized as phytotoxins, mycotoxins, or zootoxins, which include venoms and bacterial toxins. Any toxin can be harmful or beneficial. Within the last 100 years, the perception of botulinum neurotoxin (BTX) has evolved from that of a poison to a versatile clinical agent with various uses. BTX plays a key role in the management of many orofacial and dental disorders. Its indications are rapidly expanding, with ongoing trials for further applications. However, despite its clinical use, what BTX specifically does in each condition is still not clear. The main aim of this review is to describe some of the unclear aspects of this potentially useful agent, with a focus on the current research in dentistry.

  15. Long-term MODIS observations of cyanobacterial dynamics in Lake Taihu: Responses to nutrient enrichment and meteorological factors

    NASA Astrophysics Data System (ADS)

    Shi, Kun; Zhang, Yunlin; Zhou, Yongqiang; Liu, Xiaohan; Zhu, Guangwei; Qin, Boqiang; Gao, Guang

    2017-01-01

    We developed and validated an empirical model for estimating chlorophyll a concentrations (Chla) in Lake Taihu to generate a long-term Chla and algal bloom area time series from MODIS-Aqua observations for 2003 to 2013. Then, based on the long-term time series data, we quantified the responses of cyanobacterial dynamics to nutrient enrichment and climatic conditions. Chla showed substantial spatial and temporal variability. In addition, the annual mean cyanobacterial surface bloom area exhibited an increasing trend across the entire lake from 2003 to 2013, with the exception of 2006 and 2007. High air temperature and phosphorus levels in the spring can prompt cyanobacterial growth, and low wind speeds and low atmospheric pressure levels favor cyanobacterial surface bloom formation. The sensitivity of cyanobacterial dynamics to climatic conditions was found to vary by region. Our results indicate that temperature is the most important factor controlling Chla inter-annual variability followed by phosphorus and that air pressure is the most important factor controlling cyanobacterial surface bloom formation followed by wind speeds in Lake Taihu.

  16. Long-term MODIS observations of cyanobacterial dynamics in Lake Taihu: Responses to nutrient enrichment and meteorological factors

    PubMed Central

    Shi, Kun; Zhang, Yunlin; Zhou, Yongqiang; Liu, Xiaohan; Zhu, Guangwei; Qin, Boqiang; Gao, Guang

    2017-01-01

    We developed and validated an empirical model for estimating chlorophyll a concentrations (Chla) in Lake Taihu to generate a long-term Chla and algal bloom area time series from MODIS-Aqua observations for 2003 to 2013. Then, based on the long-term time series data, we quantified the responses of cyanobacterial dynamics to nutrient enrichment and climatic conditions. Chla showed substantial spatial and temporal variability. In addition, the annual mean cyanobacterial surface bloom area exhibited an increasing trend across the entire lake from 2003 to 2013, with the exception of 2006 and 2007. High air temperature and phosphorus levels in the spring can prompt cyanobacterial growth, and low wind speeds and low atmospheric pressure levels favor cyanobacterial surface bloom formation. The sensitivity of cyanobacterial dynamics to climatic conditions was found to vary by region. Our results indicate that temperature is the most important factor controlling Chla inter-annual variability followed by phosphorus and that air pressure is the most important factor controlling cyanobacterial surface bloom formation followed by wind speeds in Lake Taihu. PMID:28074871

  17. Dietary exposure to an environmental toxin triggers neurofibrillary tangles and amyloid deposits in the brain

    PubMed Central

    Cox, Paul Alan; Davis, David A.; Mash, Deborah C.; Metcalf, James S.; Banack, Sandra Anne

    2016-01-01

    Neurofibrillary tangles (NFT) and β-amyloid plaques are the neurological hallmarks of both Alzheimer's disease and an unusual paralytic illness suffered by Chamorro villagers on the Pacific island of Guam. Many Chamorros with the disease suffer dementia, and in some villages one-quarter of the adults perished from the disease. Like Alzheimer's, the causal factors of Guamanian amyotrophic lateral sclerosis/parkinsonism dementia complex (ALS/PDC) are poorly understood. In replicated experiments, we found that chronic dietary exposure to a cyanobacterial toxin present in the traditional Chamorro diet, β-N-methylamino-l-alanine (BMAA), triggers the formation of both NFT and β-amyloid deposits similar in structure and density to those found in brain tissues of Chamorros who died with ALS/PDC. Vervets (Chlorocebus sabaeus) fed for 140 days with BMAA-dosed fruit developed NFT and sparse β-amyloid deposits in the brain. Co-administration of the dietary amino acid l-serine with l-BMAA significantly reduced the density of NFT. These findings indicate that while chronic exposure to the environmental toxin BMAA can trigger neurodegeneration in vulnerable individuals, increasing the amount of l-serine in the diet can reduce the risk. PMID:26791617

  18. A review of current knowledge on toxic benthic freshwater cyanobacteria--ecology, toxin production and risk management.

    PubMed

    Catherine, Quiblier; Susanna, Wood; Isidora, Echenique-Subiabre; Mark, Heath; Aurélie, Villeneuve; Jean-François, Humbert

    2013-10-01

    Benthic cyanobacteria are found globally in plethora of environments. Although they have received less attention than their planktonic freshwater counterparts, it is now well established that they produce toxins and reports of their involvement in animal poisonings have increased markedly during the last decade. Most of the known cyanotoxins have been identified from benthic cyanobacteria including: the hepatotoxic microcystins, nodularins and cylindrospermopsins, the neurotoxic saxitoxins, anatoxin-a and homoanatoxin-a and dermatotoxins, such as lyngbyatoxin. In most countries, observations of toxic benthic cyanobacteria are fragmented, descriptive and in response to animal toxicosis events. Only a limited number of long-term studies have aimed to understand why benthic proliferations occur, and/or how toxin production is regulated. These studies have shown that benthic cyanobacterial blooms are commonly a mixture of toxic and non-toxic genotypes and that toxin concentrations can be highly variable spatially and temporally. Physiochemical parameters responsible for benthic proliferation vary among habitat type with physical disturbance (e.g., flow regimes, wave action) and nutrients commonly identified as important. As climatic conditions change and anthropogenic pressures on waterways increase, it seems likely that the prevalence of blooms of benthic cyanobacteria will increase. In this article we review current knowledge on benthic cyanobacteria: ecology, toxin-producing species, variables that regulate toxin production and bloom formation, their impact on aquatic and terrestrial organisms and current monitoring and management strategies. We suggest research needs that will assist in filling knowledge gaps and ultimately allow more robust monitoring and management protocols to be developed.

  19. Genomic deletions disrupt nitrogen metabolism pathways of a cyanobacterial diatom symbiont.

    PubMed

    Hilton, Jason A; Foster, Rachel A; Tripp, H James; Carter, Brandon J; Zehr, Jonathan P; Villareal, Tracy A

    2013-01-01

    Diatoms with symbiotic N₂-fixing cyanobacteria are often abundant in the oligotrophic open ocean gyres. The most abundant cyanobacterial symbionts form heterocysts (specialized cells for N₂ fixation) and provide nitrogen (N) to their hosts, but their morphology, cellular locations and abundances differ depending on the host. Here we show that the location of the symbiont and its dependency on the host are linked to the evolution of the symbiont genome. The genome of Richelia (found inside the siliceous frustule of Hemiaulus) is reduced and lacks ammonium transporters, nitrate/nitrite reductases and glutamine:2-oxoglutarate aminotransferase. In contrast, the genome of the closely related Calothrix (found outside the frustule of Chaetoceros) is more similar to those of free-living heterocyst-forming cyanobacteria. The genome of Richelia is an example of metabolic streamlining that has implications for the evolution of N₂-fixing symbiosis and potentially for manipulating plant-cyanobacterial interactions.

  20. Distribution and dynamics of electron transport complexes in cyanobacterial thylakoid membranes☆

    PubMed Central

    Liu, Lu-Ning

    2016-01-01

    The cyanobacterial thylakoid membrane represents a system that can carry out both oxygenic photosynthesis and respiration simultaneously. The organization, interactions and mobility of components of these two electron transport pathways are indispensable to the biosynthesis of thylakoid membrane modules and the optimization of bioenergetic electron flow in response to environmental changes. These are of fundamental importance to the metabolic robustness and plasticity of cyanobacteria. This review summarizes our current knowledge about the distribution and dynamics of electron transport components in cyanobacterial thylakoid membranes. Global understanding of the principles that govern the dynamic regulation of electron transport pathways in nature will provide a framework for the design and synthetic engineering of new bioenergetic machinery to improve photosynthesis and biofuel production. This article is part of a Special Issue entitled: Organization and dynamics of bioenergetic systems in bacteria, edited by Conrad Mullineaux. PMID:26619924

  1. CO2-limitation-inducible Green Recovery of fatty acids from cyanobacterial biomass.

    PubMed

    Liu, Xinyao; Fallon, Sarah; Sheng, Jie; Curtiss, Roy

    2011-04-26

    Using genetically modified cyanobacterial strains, we engineered a Green Recovery strategy to convert membrane lipids into fatty acids for economical and environmentally sustainable biofuel production. The Green Recovery strategy utilizes lipolytic enzymes under the control of promoters induced by CO(2) limitation. Data indicate that strains of the cyanobacterium Synechocystis sp. PCC6803 engineered for Green Recovery underwent degradation of membrane diacylglycerols upon CO(2) limitation, leading to release of fatty acids into the culture medium. Recovered fatty acid yields of 36.1 × 10(-12) mg/cell were measured in one of the engineered strains (SD239). Green Recovery can be incorporated into previously constructed fatty-acid-secretion strains, enabling fatty acid recovery from the remaining cyanobacterial biomass that will be generated during fatty acid biofuel production in photobioreactors.

  2. Synechococcus elongatus UTEX 2973, a fast growing cyanobacterial chassis for biosynthesis using light and CO₂.

    PubMed

    Yu, Jingjie; Liberton, Michelle; Cliften, Paul F; Head, Richard D; Jacobs, Jon M; Smith, Richard D; Koppenaal, David W; Brand, Jerry J; Pakrasi, Himadri B

    2015-01-30

    Photosynthetic microbes are of emerging interest as production organisms in biotechnology because they can grow autotrophically using sunlight, an abundant energy source, and CO₂, a greenhouse gas. Important traits for such microbes are fast growth and amenability to genetic manipulation. Here we describe Synechococcus elongatus UTEX 2973, a unicellular cyanobacterium capable of rapid autotrophic growth, comparable to heterotrophic industrial hosts such as yeast. Synechococcus UTEX 2973 can be readily transformed for facile generation of desired knockout and knock-in mutations. Genome sequencing coupled with global proteomics studies revealed that Synechococcus UTEX 2973 is a close relative of the widely studied cyanobacterium Synechococcus elongatus PCC 7942, an organism that grows more than two times slower. A small number of nucleotide changes are the only significant differences between the genomes of these two cyanobacterial strains. Thus, our study has unraveled genetic determinants necessary for rapid growth of cyanobacterial strains of significant industrial potential.

  3. Oligopeptides as biomarkers of cyanobacterial subpopulations. Toward an understanding of their biological role.

    PubMed

    Agha, Ramsy; Quesada, Antonio

    2014-06-23

    Cyanobacterial oligopeptides comprise a wide range of bioactive and/or toxic compounds. While current research is strongly focused on exploring new oligopeptide variants and their bioactive properties, the biological role of these compounds remains elusive. Oligopeptides production abilities show a remarkably patchy distribution among conspecific strains. This observation has prompted alternative approaches to unveil their adaptive value, based on the use of cellular oligopeptide compositions as biomarkers of intraspecific subpopulations or chemotypes in freshwater cyanobacteria. Studies addressing the diversity, distribution, and dynamics of chemotypes in natural systems have provided important insights into the structure and ecology of cyanobacterial populations and the adaptive value of oligopeptides. This review presents an overview of the fundamentals of this emerging approach and its most relevant findings, and discusses our current understanding of the role of oligopeptides in the ecology of cyanobacteria.

  4. Synechococcus elongatus UTEX 2973, a fast growing cyanobacterial chassis for biosynthesis using light and CO2

    DOE PAGES

    Yu, Jingjie; Liberton, Michelle; Cliften, Paul F.; ...

    2015-01-30

    Photosynthetic microbes are of emerging interest as production organisms in biotechnology because they can grow autotrophically using sunlight, an abundant energy source, and CO2, a greenhouse gas. Important traits for such microbes are fast growth and amenability to genetic manipulation. Here we describe Synechococcus elongatus UTEX 2973, a unicellular cyanobacterium capable of rapid autotrophic growth, comparable to heterotrophic industrial hosts such as yeast. Synechococcus 2973 can be readily transformed for facile generation of desired knockout and knock-in mutations. Genome sequencing coupled with global proteomics studies revealed that Synechococcus 2973 is a close relative of the widely studied cyanobacterium Synechococcus elongatusmore » PCC 7942, an organism that grows more than two times slower. A small number of nucleotide changes are the only significant differences between the genomes of these two cyanobacterial strains. Thus, our study has unraveled genetic determinants necessary for rapid growth of cyanobacterial strains of significant industrial potential.« less

  5. Synechococcus elongatus UTEX 2973, a fast growing cyanobacterial chassis for biosynthesis using light and CO2

    SciTech Connect

    Yu, Jingjie; Liberton, Michelle; Cliften, Paul F.; Head, Richard D.; Jacobs, Jon M.; Smith, Richard D.; Koppenaal, David W.; Brand, Jerry J.; Pakrasi, Himadri B.

    2015-01-30

    Photosynthetic microbes are of emerging interest as production organisms in biotechnology because they can grow autotrophically using sunlight, an abundant energy source, and CO2, a greenhouse gas. Important traits for such microbes are fast growth and amenability to genetic manipulation. Here we describe Synechococcus elongatus UTEX 2973, a unicellular cyanobacterium capable of rapid autotrophic growth, comparable to heterotrophic industrial hosts such as yeast. Synechococcus 2973 can be readily transformed for facile generation of desired knockout and knock-in mutations. Genome sequencing coupled with global proteomics studies revealed that Synechococcus 2973 is a close relative of the widely studied cyanobacterium Synechococcus elongatus PCC 7942, an organism that grows more than two times slower. A small number of nucleotide changes are the only significant differences between the genomes of these two cyanobacterial strains. Thus, our study has unraveled genetic determinants necessary for rapid growth of cyanobacterial strains of significant industrial potential.

  6. Oligopeptides as Biomarkers of Cyanobacterial Subpopulations. Toward an Understanding of Their Biological Role

    PubMed Central

    Agha, Ramsy; Quesada, Antonio

    2014-01-01

    Cyanobacterial oligopeptides comprise a wide range of bioactive and/or toxic compounds. While current research is strongly focused on exploring new oligopeptide variants and their bioactive properties, the biological role of these compounds remains elusive. Oligopeptides production abilities show a remarkably patchy distribution among conspecific strains. This observation has prompted alternative approaches to unveil their adaptive value, based on the use of cellular oligopeptide compositions as biomarkers of intraspecific subpopulations or chemotypes in freshwater cyanobacteria. Studies addressing the diversity, distribution, and dynamics of chemotypes in natural systems have provided important insights into the structure and ecology of cyanobacterial populations and the adaptive value of oligopeptides. This review presents an overview of the fundamentals of this emerging approach and its most relevant findings, and discusses our current understanding of the role of oligopeptides in the ecology of cyanobacteria. PMID:24960202

  7. Polymer antidotes for toxin sequestration.

    PubMed

    Weisman, Adam; Chou, Beverly; O'Brien, Jeffrey; Shea, Kenneth J

    2015-08-01

    Toxins delivered by envenomation, secreted by microorganisms, or unintentionally ingested can pose an immediate threat to life. Rapid intervention coupled with the appropriate antidote is required to mitigate the threat. Many antidotes are biological products and their cost, methods of production, potential for eliciting immunogenic responses, the time needed to generate them, and stability issues contribute to their limited availability and effectiveness. These factors exacerbate a world-wide challenge for providing treatment. In this review we evaluate a number of polymer constructs that may serve as alternative antidotes. The range of toxins investigated includes those from sources such as plants, animals and bacteria. The development of polymeric heavy metal sequestrants for use as antidotes to heavy metal poisoning faces similar challenges, thus recent findings in this area have also been included. Two general strategies have emerged for the development of polymeric antidotes. In one, the polymer acts as a scaffold for the presentation of ligands with a known affinity for the toxin. A second strategy is to generate polymers with an intrinsic affinity, and in some cases selectivity, to a range of toxins. Importantly, in vivo efficacy has been demonstrated for each of these strategies, which suggests that these approaches hold promise as an alternative to biological or small molecule based treatments.

  8. MCEARD - CYANOBACTERIA AND THEIR TOXINS

    EPA Science Inventory

    Harmful algal blooms (HAB) of cyanobacteria, also known as blue-green algae, have recently become more spatially and temporally prevalent in the US and worldwide. Waterborne cyanobacteria and their highly potent toxins are a significant hazard for human health and the ecosystem....

  9. Risk Assessment of Shellfish Toxins

    PubMed Central

    Munday, Rex; Reeve, John

    2013-01-01

    Complex secondary metabolites, some of which are highly toxic to mammals, are produced by many marine organisms. Some of these organisms are important food sources for marine animals and, when ingested, the toxins that they produce may be absorbed and stored in the tissues of the predators, which then become toxic to animals higher up the food chain. This is a particular problem with shellfish, and many cases of poisoning are reported in shellfish consumers each year. At present, there is no practicable means of preventing uptake of the toxins by shellfish or of removing them after harvesting. Assessment of the risk posed by such toxins is therefore required in order to determine levels that are unlikely to cause adverse effects in humans and to permit the establishment of regulatory limits in shellfish for human consumption. In the present review, the basic principles of risk assessment are described, and the progress made toward robust risk assessment of seafood toxins is discussed. While good progress has been made, it is clear that further toxicological studies are required before this goal is fully achieved. PMID:24226039

  10. The composition of the global and feature specific cyanobacterial core-genomes

    PubMed Central

    Simm, Stefan; Keller, Mario; Selymesi, Mario; Schleiff, Enrico

    2015-01-01

    Cyanobacteria are photosynthetic prokaryotes important for many ecosystems with a high potential for biotechnological usage e.g., in the production of bioactive molecules. Either asks for a deep understanding of the functionality of cyanobacteria and their interaction with the environment. This in part can be inferred from the analysis of their genomes or proteomes. Today, many cyanobacterial genomes have been sequenced and annotated. This information can be used to identify biological pathways present in all cyanobacteria as proteins involved in such processes are encoded by a so called core-genome. However, beside identification of fundamental processes, genes specific for certain cyanobacterial features can be identified by a holistic genome analysis as well. We identified 559 genes that define the core-genome of 58 analyzed cyanobacteria, as well as three genes likely to be signature genes for thermophilic and 57 genes likely to be signature genes for heterocyst-forming cyanobacteria. To get insights into cyanobacterial systems for the interaction with the environment we also inspected the diversity of the outer membrane proteome with focus on β-barrel proteins. We observed that most of the transporting outer membrane β-barrel proteins are not globally conserved in the cyanobacterial phylum. In turn, the occurrence of β-barrel proteins shows high strain specificity. The core set of outer membrane proteins globally conserved in cyanobacteria comprises three proteins only, namely the outer membrane β-barrel assembly protein Omp85, the lipid A transfer protein LptD, and an OprB-type porin. Thus, we conclude that cyanobacteria have developed individual strategies for the interaction with the environment, while other intracellular processes like the regulation of the protein homeostasis are globally conserved. PMID:25852675

  11. Molecular mechanisms of tolerance to cyanobacterial protease inhibitors revealed by clonal differences in Daphnia magna.

    PubMed

    Schwarzenberger, Anke; Kuster, Christian J; Von Elert, Eric

    2012-10-01

    Protease inhibitors of primary producers are a major food quality constraint for herbivores. In nutrient-rich freshwater ecosystems, the interaction between primary producers and herbivores is mainly represented by Daphnia and cyanobacteria. Protease inhibitors have been found in many cyanobacterial blooms. These inhibitors have been shown (both in vitro and in situ) to inhibit the most important group of digestive proteases in the daphnid's gut, that is, trypsins and chymotrypsins. In this study, we fed four different Daphnia magna genotypes with the trypsin-inhibitor-containing cyanobacterial strain Microcystis aeruginosa PCC 7806 Mut. Upon exposure to dietary trypsin inhibitors, all D. magna genotypes showed increased gene expression of digestive trypsins and chymotrypsins. Exposure to dietary trypsin inhibitors resulted in increased activity of chymotrypsins and reduced activity of trypsin. Strong intraspecific differences in tolerance of the four D. magna genotypes to the dietary trypsin inhibitors were found. The degree of tolerance depended on the D. magna genotype. The genotypes' tolerance was positively correlated with the residual trypsin activity and the different IC(50) values of the trypsins. On the genetic level, the different trypsin loci varied between the D. magna genotypes. The two tolerant Daphnia genotypes that both originate from the same lake, which frequently produces cyanobacterial blooms, clustered in a neighbour-joining phylogenetic tree based on the three trypsin loci. This suggests that the genetic variability of trypsin loci was an important cause for the observed intraspecific variability in tolerance to cyanobacterial trypsin inhibitors. Based on these findings, it is reasonable to assume that such genetic variability can also be found in natural populations and thus constitutes the basis for local adaptation of natural populations to dietary protease inhibitors.

  12. Genetic tools for advancement of Synechococcus sp. PCC 7002 as a cyanobacterial chassis

    SciTech Connect

    Ruffing, Anne M.; Jensen, Travis J.; Strickland, Lucas M.

    2016-11-10

    Successful implementation of modified cyanobacteria as hosts for industrial applications requires the development of a cyanobacterial chassis. The cyanobacterium Synechococcus sp. PCC 7002 embodies key attributes for an industrial host, including a fast growth rate and high salt, light, and temperature tolerances. Here, this study addresses key limitations in the advancement of Synechococcus sp. PCC 7002 as an industrial chassis.

  13. Experimental additions of aluminum sulfateand ammonium nitrate to in situ mesocosms toreduce cyanobacterial biovolume and microcystinconcentration

    USGS Publications Warehouse

    Harris, Theodore D.; Wilhelm, Frank M.; Graham, Jennifer L.; Loftin, Keith A.

    2014-01-01

    Recent studies suggest that nitrogen additions to increase the total nitrogen:total phosphorus (TN:TP) ratio may reduce cyanobacterial biovolume and microcystin concentration in reservoirs. In systems where TP is >100 μg/L, however, nitrogen additions to increase the TN:TP ratio could cause ammonia, nitrate, or nitrite toxicity to terrestrial and aquatic organisms. Reducing phosphorus via aluminum sulfate (alum) may be needed prior to nitrogen additions aimed at increasing the TN:TP ratio.We experimentally tested this sequential management approach in large in situ mesocosms (70.7 m3) to examine effects on cyanobacteria and microcystin concentration. Because alum removes nutrients and most seston from the water column, alum treatment reduced both TN and TP, leaving post-treatment TN:TP ratios similar to pre-treatment ratios. Cyanobacterial biovolume was reduced after alum addition, but the percent composition (i.e., relative) cyanobacterial abundance remained unchanged. A single ammonium nitrate (nitrogen) addition increased the TN:TP ratio 7-fold. After the TN:TP ratio was >50 (by weight), cyanobacterial biovolume and abundance were reduced, and chrysophyte and cryptophyte biovolume and abundance increased compared to the alum treatment. Microcystin was not detectable until the TN:TP ratio was <50. Although both treatments reduced cyanobacteria, only the nitrogen treatment seemed to stimulate energy flow from primary producers to zooplankton, which suggests that combining alum and nitrogen treatments may be a viable in-lake management strategy to reduce cyanobacteria and possibly microcystin concentrations in high-phosphorus systems. Additional studies are needed to define best management practices before combined alum and nitrogen additions are implemented as a reservoir management strategy.

  14. SAR analysis and bioactive potentials of freshwater and terrestrial cyanobacterial compounds: a review.

    PubMed

    Nagarajan, M; Maruthanayagam, V; Sundararaman, M

    2013-05-01

    Freshwater and terrestrial cyanobacteria resemble the marine forms in producing divergent chemicals such as linear, cyclic and azole containing peptides, alkaloids, cyclophanes, terpenes, lactones, etc. These metabolites have wider biomedical potentials in targeting proteases, cancers, parasites, pathogens and other cyanobacteria and algae (allelopathy). Among the various families of non-marine cyanobacterial peptides reported, many of them are acting as serine protease inhibitors. While the micropeptin family has a preference for chymotrypsin inhibition rather than other serine proteases, the aeruginosin family targets trypsin and thrombin. In addition, cyanobacterial compounds such as scytonemide A, lyngbyazothrins C and D and cylindrocyclophanes were found to inhibit 20S proteosome. Apart from proteases, metabolites blocking the other targets of cancer pathways may exhibit cytotoxic effect. Colon and rectum, breast, lung and prostate are the worst affecting cancers in humans and are deduced to be inhibited by both peptidic and non-peptidic compounds. Moreover, the growth of infections causing parasites such as Plasmodium, Leishmania and Trypanosoma are well controlled by peptides: aerucyclamides A-D, tychonamides and alkaloids: nostocarboline and calothrixins. Likewise, varieties of cyanobacterial compounds tend to inhibit serious infectious disease causing bacterial, fungal and viral agents. Interestingly, portoamides, spiroidesin, nostocyclamide and kasumigamide are the allelopathic peptides determined to suppress the growth of toxic cyanobacteria and nuisance algae. Thus cyanobacterial compounds have a broad bioactive spectrum; the analysis of SAR studies will not only assist to find out the mode of action but also reveal bioactive key components. Thereby, developing the drugs bearing these bioactive skeletons to treat various illnesses is wide open.

  15. Cyanobacterial biomass as carbohydrate and nutrient feedstock for bioethanol production by yeast fermentation

    PubMed Central

    2014-01-01

    Background Microbial bioconversion of photosynthetic biomass is a promising approach to the generation of biofuels and other bioproducts. However, rapid, high-yield, and simple processes are essential for successful applications. Here, biomass from the rapidly growing photosynthetic marine cyanobacterium Synechococcus sp. PCC 7002 was fermented using yeast into bioethanol. Results The cyanobacterium accumulated a total carbohydrate content of about 60% of cell dry weight when cultivated under nitrate limitation. The cyanobacterial cells were harvested by centrifugation and subjected to enzymatic hydrolysis using lysozyme and two alpha-glucanases. This enzymatic hydrolysate was fermented into ethanol by Saccharomyces cerevisiae without further treatment. All enzyme treatments and fermentations were carried out in the residual growth medium of the cyanobacteria with the only modification being that pH was adjusted to the optimal value. The highest ethanol yield and concentration obtained was 0.27 g ethanol per g cell dry weight and 30 g ethanol L-1, respectively. About 90% of the glucose in the biomass was converted to ethanol. The cyanobacterial hydrolysate was rapidly fermented (up to 20 g ethanol L-1 day-1) even in the absence of any other nutrient additions to the fermentation medium. Conclusions Cyanobacterial biomass was hydrolyzed using a simple enzymatic treatment and fermented into ethanol more rapidly and to higher concentrations than previously reported for similar approaches using cyanobacteria or microalgae. Importantly, as well as fermentable carbohydrates, the cyanobacterial hydrolysate contained additional nutrients that promoted fermentation. This hydrolysate is therefore a promising substitute for the relatively expensive nutrient additives (such as yeast extract) commonly used for Saccharomyces fermentations. PMID:24739806

  16. Effects of Hydrogen Peroxide and Ultrasound on Biomass Reduction and Toxin Release in the Cyanobacterium, Microcystis aeruginosa

    PubMed Central

    Lürling, Miquel; Meng, Debin; Faassen, Elisabeth J.

    2014-01-01

    Cyanobacterial blooms are expected to increase, and the toxins they produce threaten human health and impair ecosystem services. The reduction of the nutrient load of surface waters is the preferred way to prevent these blooms; however, this is not always feasible. Quick curative measures are therefore preferred in some cases. Two of these proposed measures, peroxide and ultrasound, were tested for their efficiency in reducing cyanobacterial biomass and potential release of cyanotoxins. Hereto, laboratory assays with a microcystin (MC)-producing cyanobacterium (Microcystis aeruginosa) were conducted. Peroxide effectively reduced M. aeruginosa biomass when dosed at 4 or 8 mg L−1, but not at 1 and 2 mg L−1. Peroxide dosed at 4 or 8 mg L−1 lowered total MC concentrations by 23%, yet led to a significant release of MCs into the water. Dissolved MC concentrations were nine-times (4 mg L−1) and 12-times (8 mg L−1 H2O2) higher than in the control. Cell lysis moreover increased the proportion of the dissolved hydrophobic variants, MC-LW and MC-LF (where L = Leucine, W = tryptophan, F = phenylalanine). Ultrasound treatment with commercial transducers sold for clearing ponds and lakes only caused minimal growth inhibition and some release of MCs into the water. Commercial ultrasound transducers are therefore ineffective at controlling cyanobacteria. PMID:25513892

  17. Inactivation of allergens and toxins.

    PubMed

    Morandini, Piero

    2010-11-30

    Plants are replete with thousands of proteins and small molecules, many of which are species-specific, poisonous or dangerous. Over time humans have learned to avoid dangerous plants or inactivate many toxic components in food plants, but there is still room for ameliorating food crops (and plants in general) in terms of their allergens and toxins content, especially in their edible parts. Inactivation at the genetic rather than physical or chemical level has many advantages and classical genetic approaches have resulted in significant reduction of toxin content. The capacity, offered by genetic engineering, of turning off (inactivating) specific genes has opened up the possibility of altering the plant content in a far more precise manner than previously available. Different levels of intervention (genes coding for toxins/allergens or for enzymes, transporters or regulators involved in their metabolism) are possible and there are several tools for inactivating genes, both direct (using chemical and physical mutagens, insertion of transposons and other genetic elements) and indirect (antisense RNA, RNA interference, microRNA, eventually leading to gene silencing). Each level/strategy has specific advantages and disadvantages (speed, costs, selectivity, stability, reversibility, frequency of desired genotype and regulatory regime). Paradigmatic examples from classical and transgenic approaches are discussed to emphasize the need to revise the present regulatory process. Reducing the content of natural toxins is a trade-off process: the lesser the content of natural toxins, the higher the susceptibility of a plant to pests and therefore the stronger the need to protect plants. As a consequence, more specific pesticides like Bt are needed to substitute for general pesticides.

  18. Complex polar lipids of a hot spring cyanobacterial mat and its cultivated inhabitants

    NASA Technical Reports Server (NTRS)

    Ward, D. M.; Panke, S.; Kloppel, K. D.; Christ, R.; Fredrickson, H.

    1994-01-01

    The complex polar lipids of the hot spring cyanobacterial mat in the 50 to 55 degrees C region of Octopus Spring, Yellowstone National Park, and of thermophilic bacteria cultivated from this or similar habitats, were compared in an attempt to understand the microbial sources of the major lipid biomarkers in this community. Intact complex lipids were analyzed directly by fast atom bombardment mass spectrometry (FAB-MS), two-dimensional thin-layer chromatography (TLC), and combined TLC-FAB-MS. FAB-MS and TLC gave qualitatively similar results, suggesting that the mat contains major lipids most like those of the cyanobacterial isolate we studied, Synechococcus sp. strain Y-7c-s. These include monoglycosyl, diglycosyl, and sulfoquinosovyl diglycerides (MG, DG, and SQ, respectively) and phosphatidyl glycerol (PG). Though Chloroflexus aurantiacus also contains MG, DG, and PG, the fatty acid chain lengths of mat MGs, DGs, and PGs resemble more those of cyanobacterial than green nonsulfur bacterial lipids. FAB-MS spectra of the lipids of nonphototrophic bacterial isolates were distinctively different from those of the mat and phototrophic isolates. The lipids of these nonphototrophic isolates were not detected in the mat, but most could be detected when added to mat samples. The mat also contains major glycolipids and aminophospholipids of unknown structure and origin. FAB-MS and TLC did not always give quantitatively similar results. In particular, PG and SQ may give disproportionately high FAB-MS responses.

  19. Three-dimensional structure and cyanobacterial activity within a desert biological soil crust.

    PubMed

    Raanan, Hagai; Felde, Vincent J M N L; Peth, Stephan; Drahorad, Sylvie; Ionescu, Danny; Eshkol, Gil; Treves, Haim; Felix-Henningsen, Peter; Berkowicz, Simon M; Keren, Nir; Horn, Rainer; Hagemann, Martin; Kaplan, Aaron

    2016-02-01

    Desert biological soil crusts (BSCs) are formed by adhesion of soil particles to polysaccharides excreted by filamentous cyanobacteria, the pioneers and main producers in this habitat. Biological soil crust destruction is a central factor leading to land degradation and desertification. We study the effect of BSC structure on cyanobacterial activity. Micro-scale structural analysis using X-ray microtomography revealed a vesiculated layer 1.5-2.5 mm beneath the surface in close proximity to the cyanobacterial location. Light profiles showed attenuation with depth of 1%-5% of surface light within 1 mm but also revealed the presence of 'light pockets', coinciding with the vesiculated layer, where the irradiance was 10-fold higher than adjacent crust parts at the same depth. Maximal photosynthetic activity, examined by O2 concentration profiles, was observed 1 mm beneath the surface and another peak in association with the 'light pockets'. Thus, photosynthetic activity may not be visible to currently used remote sensing techniques, suggesting that BSCs' contribution to terrestrial productivity is underestimated. Exposure to irradiance higher than 10% full sunlight diminished chlorophyll fluorescence, whereas O2 evolution and CO2 uptake rose, indicating that fluorescence did not reflect cyanobacterial photosynthetic activity. Our data also indicate that although resistant to high illumination, the BSC-inhabiting cyanobacteria function as 'low-light adapted' organisms.

  20. Dynamic metabolic profiling of cyanobacterial glycogen biosynthesis under conditions of nitrate depletion.

    PubMed

    Hasunuma, Tomohisa; Kikuyama, Fumi; Matsuda, Mami; Aikawa, Shimpei; Izumi, Yoshihiro; Kondo, Akihiko

    2013-07-01

    Cyanobacteria represent a globally important biomass because they are responsible for a substantial proportion of primary production in the hydrosphere. Arthrospira platensis is a fast-growing halophilic cyanobacterium capable of accumulating glycogen and has the potential to serve as a feedstock in the fermentative production of third-generation biofuels. Accordingly, enhancing cyanobacterial glycogen production is a promising biofuel production strategy. However, the regulatory mechanism of glycogen metabolism in cyanobacteria is poorly understood. The aim of the present study was to determine the metabolic flux of glycogen biosynthesis using a dynamic metabolomic approach. Time-course profiling of widely targeted cyanobacterial metabolic intermediates demonstrated a global metabolic reprogramming that involves transient increases in the levels of some amino acids during the glycogen production phase induced by nitrate depletion. Also, in vivo labelling with NaH(13)CO3 enabled direct measurement of metabolic intermediate turnover in A. platensis, revealing that under conditions of nitrate depletion glycogen is biosynthesized with carbon derived from amino acids released from proteins via gluconeogenesis. This dynamic metabolic profiling approach provided conclusive evidence of temporal alterations in the metabolic profile in cyanobacterial cells.

  1. Purification and characterization of C-Phycocyanin from cyanobacterial species of marine and freshwater habitat.

    PubMed

    Patel, Anamika; Mishra, Sandhya; Pawar, Richa; Ghosh, P K

    2005-04-01

    The present paper describes an efficient single step chromatographic method for purification of C-Phycocyanin from three cyanobacterial species, i.e., Spirulina sp. (freshwater), Phormidium sp. (marine water) and Lyngbya sp. (marine water). C-Phycocyanin from these cyanobacterial species was purified to homogeneity and some of their properties were investigated. The purification involves a multistep treatment of the crude extract by fractional precipitation with ammonium sulfate, followed by ion-exchange chromatography on DEAE-Sepharose CL-6B column. Pure C-Phycocyanin was finally obtained from Spirulina, Phormidium, and Lyngbya spp. with purity ratio (A620/A280) 4.42, 4.43, and 4.59, respectively, further the purity and homogeneity were confirmed by native and SDS-PAGE. The estimated molecular weights of purified C-PC from Spirulina, Phormidium, and Lyngbya spp. were 112, 131, and 81 kDa, respectively. SDS-PAGE of pure C-Phycocyanin yielded two bands corresponding to alpha and beta subunits. The results of SDS-PAGE demonstrate the same molecular weight of beta subunits (24.4 kDa) for all the three cyanobacterial species, whereas the molecular weight of the alpha subunit is different for all (17 kDa Spirulina sp., 19.1 kDa Phormidium sp., 15.2 kDa Lyngbya sp.). Thus, the C-Phycocyanin was characterized as (alphabeta)3 for Spirulina and Phormidium spp., while as (alphabeta)2 for Lyngbya sp.

  2. Scytonin, a novel cyanobacterial photoprotective pigment: calculations of Raman spectroscopic biosignatures.

    PubMed

    Varnali, Tereza; Edwards, Howell G M

    2014-03-01

    The Raman spectrum of scytonin, a novel derivative of the parent scytonemin, is predicted from DFT calculations of the most stable, lowest energy, conformational structure. The diagnostic importance of this study relates to the spectral ability to discriminate between scytonemin and its derivatives alone or in admixture with geological matrices from identified characteristic Raman spectral signatures. The successful interpretation of biosignatures from a wide range of cyanobacterial extremophilic colonization in terrestrial and extraterrestrial scenarios is a fundamental requirement of the evaluation of robotic spectroscopic instrumentation in search for life missions. Scytonemin is produced exclusively by cyanobacterial colonies in environmentally stressed habitats and is widely recognized as a key target biomarker molecule in this enterprise. Here, the detailed theoretical analysis of the structure of scytonin enables a protocol to be established for the recognition of characteristic bands in its Raman spectrum and to accomplish the successful differentiation between scytonin and scytonemin as well as other scytonemin derivatives such as the dimethoxy and tetramethoxy compounds that have been isolated from cyanobacterial colonies but which have not yet been characterized spectroscopically. The results of this study will facilitate an extension of the database capability for miniaturized Raman spectrometers which will be carried on board search for life robotic missions to Mars, Europa, and Titan.

  3. Electrochemical Detection of Circadian Redox Rhythm in Cyanobacterial Cells via Extracellular Electron Transfer.

    PubMed

    Nishio, Koichi; Pornpitra, Tunanunkul; Izawa, Seiichiro; Nishiwaki-Ohkawa, Taeko; Kato, Souichiro; Hashimoto, Kazuhito; Nakanishi, Shuji

    2015-06-01

    Recent research on cellular circadian rhythms suggests that the coupling of transcription-translation feedback loops and intracellular redox oscillations is essential for robust circadian timekeeping. For clarification of the molecular mechanism underlying the circadian rhythm, methods that allow for the dynamic and simultaneous detection of transcription/translation and redox oscillations in living cells are needed. Herein, we report that the cyanobacterial circadian redox rhythm can be electrochemically detected based on extracellular electron transfer (EET), a process in which intracellular electrons are exchanged with an extracellular electrode. As the EET-based method is non-destructive, concurrent detection with transcription/translation rhythm using bioluminescent reporter strains becomes possible. An EET pathway that electrochemically connected the intracellular region of cyanobacterial cells with an extracellular electrode was constructed via a newly synthesized electron mediator with cell membrane permeability. In the presence of the mediator, the open circuit potential of the culture medium exhibited temperature-compensated rhythm with approximately 24 h periodicity. Importantly, such circadian rhythm of the open circuit potential was not observed in the absence of the electron mediator, indicating that the EET process conveys the dynamic information regarding the intracellular redox state to the extracellular electrode. These findings represent the first direct demonstration of the intracellular circadian redox rhythm of cyanobacterial cells.

  4. The current status of cyanobacterial nomenclature under the "prokaryotic" and the "botanical" code.

    PubMed

    Oren, Aharon; Ventura, Stefano

    2017-02-27

    Cyanobacterial taxonomy developed in the botanical world because Cyanobacteria/Cyanophyta have traditionally been identified as algae. However, they possess a prokaryotic cell structure, and phylogenetically they belong to the Bacteria. This caused nomenclature problems as the provisions of the International Code of Nomenclature for algae, fungi, and plants (ICN; the "Botanical Code") differ from those of the International Code of Nomenclature of Prokaryotes (ICNP; the "Prokaryotic Code"). While the ICN recognises names validly published under the ICNP, Article 45(1) of the ICN has not yet been reciprocated in the ICNP. Different solutions have been proposed to solve the current problems. In 2012 a Special Committee on the harmonisation of the nomenclature of Cyanobacteria was appointed, but its activity has been minimal. Two opposing proposals to regulate cyanobacterial nomenclature were recently submitted, one calling for deletion of the cyanobacteria from the groups of organisms whose nomenclature is regulated by the ICNP, the second to consistently apply the rules of the ICNP to all cyanobacteria. Following a general overview of the current status of cyanobacterial nomenclature under the two codes we present five case studies of genera for which nomenclatural aspects have been discussed in recent years: Microcystis, Planktothrix, Halothece, Gloeobacter and Nostoc.

  5. Role of Cyanobacterial Exopolysaccharides in Phototrophic Biofilms and in Complex Microbial Mats

    PubMed Central

    Rossi, Federico; De Philippis, Roberto

    2015-01-01

    Exopolysaccharides (EPSs) are an important class of biopolymers with great ecological importance. In natural environments, they are a common feature of microbial biofilms, where they play key protective and structural roles. As the primary colonizers of constrained environments, such as desert soils and lithic and exposed substrates, cyanobacteria are the first contributors to the synthesis of the EPSs constituting the extracellular polymeric matrix that favors the formation of microbial associations with varying levels of complexity called biofilms. Cyanobacterial colonization represents the first step for the formation of biofilms with different levels of complexity. In all of the possible systems in which cyanobacteria are involved, the synthesis of EPSs contributes a structurally-stable and hydrated microenvironment, as well as chemical/physical protection against biotic and abiotic stress factors. Notwithstanding the important roles of cyanobacterial EPSs, many aspects related to their roles and the relative elicited biotic and abiotic factors have still to be clarified. The aim of this survey is to outline the state-of-the-art of the importance of the cyanobacterial EPS excretion, both for the producing cells and for the microbial associations in which cyanobacteria are a key component. PMID:25837843

  6. Antibody microarrays for native toxin detection.

    PubMed

    Rucker, Victor C; Havenstrite, Karen L; Herr, Amy E

    2005-04-15

    We have developed antibody-based microarray techniques for the multiplexed detection of cholera toxin beta-subunit, diphtheria toxin, anthrax lethal factor and protective antigen, Staphylococcus aureus enterotoxin B, and tetanus toxin C fragment in spiked samples. Two detection schemes were investigated: (i) a direct assay in which fluorescently labeled toxins were captured directly by the antibody array and (ii) a competition assay that employed unlabeled toxins as reporters for the quantification of native toxin in solution. In the direct assay, fluorescence measured at each array element is correlated with labeled toxin concentration to yield baseline binding information (Langmuir isotherms and affinity constants). Extending from the direct assay, the competition assay yields information on the presence, identity, and concentration of toxins. A significant advantage of the competition assay over reported profiling assays is the minimal sample preparation required prior to analysis because the competition assay obviates the need to fluorescently label native proteins in the sample of interest. Sigmoidal calibration curves and detection limits were established for both assay formats. Although the sensitivity of the direct assay is superior to that of the competition assay, detection limits for unmodified toxins in the competition assay are comparable to values reported previously for sandwich-format immunoassays of antibodies arrayed on planar substrates. As a demonstration of the potential of the competition assay for unlabeled toxin detection, we conclude with a straightforward multiplexed assay for the differentiation and identification of both native S. aureus enterotoxin B and tetanus toxin C fragment in spiked dilute serum samples.

  7. Toxins as Weapons: A Historical Review.

    PubMed

    Pita, R; Romero, A

    2014-07-01

    This review article summarizes the use of toxins as weapons dating from the First World War until today, when there is a high concern of possible terrorist attacks with weapons of mass destruction. All through modern history, military programs and terrorist groups have favored toxins because of their high toxicity. However, difficulties of extraction or synthesis, as well as effective dissemination to cause a large number of casualties, have been the most important drawbacks. Special emphasis is focused on ricin and botulinum toxin, the most important toxins that have attracted the attention of military programs and terrorist groups. Other toxins like trichothecenes, saxitoxin, and Staphylococcal enterotoxin B (SEB) are also discussed. A short section about anthrax is also included: Although Bacillus anthracis is considered a biological weapon rather than a toxin weapon, it produces a toxin that is finally responsible for the anthrax disease.

  8. Antibody-based bacterial toxin detection

    NASA Astrophysics Data System (ADS)

    Menking, Darrell E.; Heitz, Jonathon M.; Anis, Nabil A.; Thompson, Roy G.

    1994-03-01

    Fiber optic evanescent fluorosensors are under investigation in our laboratory for the study of drug-receptor interactions for detection of threat agents and antibody-antigen interactions for detection of biological toxins. In a one step assay, antibodies against Cholera toxin or Staphylococcus Enterotoxin B were noncovalently immobilized on quartz fibers and probed with fluorescein-isothiocyanate (FITC)-labeled toxins. In the two-step assay, Cholera toxin or Botulinum toxoid A was immobilized onto the fiber, followed by incubation in an antiserum or partially purified antitoxin IgG. These were then probed with FITC-anti-IgG antibodies. Unlabeled toxins competed with labeled toxins or antitoxin IgG in a dose-dependent manner and the detection of the toxins was in the nanomolar range.

  9. Nemertean Toxin Genes Revealed through Transcriptome Sequencing

    PubMed Central

    Whelan, Nathan V.; Kocot, Kevin M.; Santos, Scott R.; Halanych, Kenneth M.

    2014-01-01

    Nemerteans are one of few animal groups that have evolved the ability to utilize toxins for both defense and subduing prey, but little is known about specific nemertean toxins. In particular, no study has identified specific toxin genes even though peptide toxins are known from some nemertean species. Information about toxin genes is needed to better understand evolution of toxins across animals and possibly provide novel targets for pharmaceutical and industrial applications. We sequenced and annotated transcriptomes of two free-living and one commensal nemertean and annotated an additional six publicly available nemertean transcriptomes to identify putative toxin genes. Approximately 63–74% of predicted open reading frames in each transcriptome were annotated with gene names, and all species had similar percentages of transcripts annotated with each higher-level GO term. Every nemertean analyzed possessed genes with high sequence similarities to known animal toxins including those from stonefish, cephalopods, and sea anemones. One toxin-like gene found in all nemerteans analyzed had high sequence similarity to Plancitoxin-1, a DNase II hepatotoxin that may function well at low pH, which suggests that the acidic body walls of some nemerteans could work to enhance the efficacy of protein toxins. The highest number of toxin-like genes found in any one species was seven and the lowest was three. The diversity of toxin-like nemertean genes found here is greater than previously documented, and these animals are likely an ideal system for exploring toxin evolution and industrial applications of toxins. PMID:25432940

  10. Light Regimes Shape Utilization of Extracellular Organic C and N in a Cyanobacterial Biofilm

    SciTech Connect

    Stuart, Rhona K.; Mayali, Xavier; Boaro, Amy A.; Zemla, Adam; Everroad, R. Craig; Nilson, Daniel; Weber, Peter K.; Lipton, Mary; Bebout, Brad M.; Pett-Ridge, Jennifer; Thelen, Michael P.

    2016-06-28

    Although it is becoming clear that many microbial primary producers can also play a role as organic consumers, we know very little about the metabolic regulation of photoautotroph organic matter consumption. Cyanobacteria in phototrophic biofilms can reuse extracellular organic carbon, but the metabolic drivers of extracellular processes are surprisingly complex. We investigated the metabolic foundations of organic matter reuse by comparing exoproteome composition and incorporation of13C-labeled and15N-labeled cyanobacterial extracellular organic matter (EOM) in a unicyanobacterial biofilm incubated using different light regimes. In the light and the dark, cyanobacterial direct organic C assimilation accounted for 32% and 43%, respectively, of all organic C assimilation in the community. Under photosynthesis conditions, we measured increased excretion of extracellular polymeric substances (EPS) and proteins involved in micronutrient transport, suggesting that requirements for micronutrients may drive EOM assimilation during daylight hours. This interpretation was supported by photosynthesis inhibition experiments, in which cyanobacteria incorporated N-rich EOM-derived material. In contrast, under dark, C-starved conditions, cyanobacteria incorporated C-rich EOM-derived organic matter, decreased excretion of EPS, and showed an increased abundance of degradative exoproteins, demonstrating the use of the extracellular domain for C storage. Sequence-structure modeling of one of these exoproteins predicted a specific hydrolytic activity that was subsequently detected, confirming increased EOM degradation in the dark. Associated heterotrophic bacteria increased in abundance and upregulated transport proteins under dark relative to light conditions. Taken together, our results indicate that biofilm cyanobacteria are successful competitors for organic C and N and that cyanobacterial nutrient and energy requirements control the use of EOM.

  11. Epidemiology of cancers in Serbia and possible connection with cyanobacterial blooms.

    PubMed

    Svirčev, Zorica; Drobac, Damjana; Tokodi, Nada; Lužanin, Zorana; Munjas, Ana Marija; Nikolin, Branislava; Vuleta, Dušan; Meriluoto, Jussi

    2014-01-01

    Cyanobacteria produce toxic metabolites known as cyanotoxins. These bioactive compounds can cause acute poisoning, and some of them may promote cancer through chronic exposure. Direct ingestion of and contact with contaminated water is one of the many exposure routes to cyanotoxins. The aim of this article was to review the incidence of 13 cancers during a 10-year period in Serbia and to assess whether there is a correlation between the cancer incidences and cyanobacterial bloom occurrence in reservoirs for drinking water supply. The types of cancers were chosen and subjected to epidemiological analyses utilizing previously published data. Based on the epidemiological and statistical analysis, the group of districts in which the incidences of cancers are significant, and may be considered as critical, include Nišavski, Toplički, and Šumadijski district. A significantly higher incidence of ten cancers was observed in the three critical districts as compared to the remaining 14 districts in Central Serbia. These elevated incidences of cancer include: brain cancer, heart, mediastinum and pleura cancer, ovary cancer, testicular cancer, gastric cancer, colorectal cancer, retroperitoneum and peritoneum cancer, leukemia, malignant melanoma of skin, and primary liver cancer. In addition, the mean incidence of five chosen cancers was the highest in the three critical regions, then in the rest of Central Serbia, while the lowest values were recorded in Vojvodina. Persistent and recurrent cyanobacterial blooms occur during summer months in reservoirs supplying water to waterworks in the three critical districts. People in Central Serbia mainly use surface water as water supply (but not all the water bodies are blooming) while in Vojvodina region (control region in this study) only groundwater is used. Among the 14 "noncritical" districts, reservoirs used for drinking water supply have been affected by recurrent cyanobacterial blooms in two districts (Rasinski and Zaje

  12. Evaluating the effectiveness of copper sulphate, chlorine, potassium permanganate, hydrogen peroxide and ozone on cyanobacterial cell integrity.

    PubMed

    Fan, Jiajia; Ho, Lionel; Hobson, Peter; Brookes, Justin

    2013-09-15

    Cyanobacterial blooms are continuously critical challenges in drinking water systems which can have various negative impacts such as production of taste, odour and toxic compounds. Furthermore, the intracellular metabolites could be released into surrounding waters when the cyanobacterial membranes are destroyed. Although a variety of techniques have been developed to control cyanobacterial blooms and remove cyanobacterial cells or metabolites in water treatment processes, the effect of these treatments on the membrane integrity of cyanobacterial cells have not been systematically studied and compared. This study evaluated the effectiveness of copper sulphate (CuSO4), chlorine, potassium permanganate (KMnO4), hydrogen peroxide (H2O2) and ozone on the cell integrity and densities of Microcystis aeruginosa. All of these technologies can compromise the cell membrane of cyanobacteria to varying degrees. Chlorine showed the strongest ability to impair the cell integrity with a majority (≥ 88%) of the cells compromised within the first minute and with the cell lysis rates ranging of 0.640-3.82 h(-1) during 1-60 min. Ozone dose of 6 mg L(-1) also could induce 90% lysis of the cyanobacterial cells in 5 min and the cell lysis rate of KMnO4 (10 mg L(-1)) was 0.829 h(-1). CuSO4 and H2O2 could not only destroy the viability of cyanobacterial cells but also showed algistatic potential over the 7 day treatment. The potential of all the oxidants (chlorine, KMnO4, H2O2 and ozone) considered as algicides were discussed in this study. The benefits and drawbacks of these control and water treatment options were assessed as well.

  13. Why do we study animal toxins?

    PubMed Central

    ZHANG, Yun

    2015-01-01

    Venom (toxins) is an important trait evolved along the evolutionary tree of animals. Our knowledges on venoms, such as their origins and loss, the biological relevance and the coevolutionary patterns with other organisms are greatly helpful in understanding many fundamental biological questions, i.e., the environmental adaptation and survival competition, the evolution shaped development and balance of venoms, and the sophisticated correlations among venom, immunity, body power, intelligence, their genetic basis, inherent association, as well as the cost-benefit and trade-offs of biological economy. Lethal animal envenomation can be found worldwide. However, from foe to friend, toxin studies have led lots of important discoveries and exciting avenues in deciphering and fighting human diseases, including the works awarded the Nobel Prize and lots of key clinic therapeutics. According to our survey, so far, only less than 0.1% of the toxins of the venomous animals in China have been explored. We emphasize on the similarities shared by venom and immune systems, as well as the studies of toxin knowledge-based physiological toxin-like proteins/peptides (TLPs). We propose the natural pairing hypothesis. Evolution links toxins with humans. Our mission is to find out the right natural pairings and interactions of our body elements with toxins, and with endogenous toxin-like molecules. Although, in nature, toxins may endanger human lives, but from a philosophical point of view, knowing them well is an effective way to better understand ourselves. So, this is why we study toxins. PMID:26228472

  14. Toxins-antitoxins: diversity, evolution and function.

    PubMed

    Hayes, Finbarr; Van Melderen, Laurence

    2011-10-01

    Genes for toxin-antitoxin (TA) complexes are widespread in prokaryote genomes, and species frequently possess tens of plasmid and chromosomal TA loci. The complexes are categorized into three types based on genetic organization and mode of action. The toxins universally are proteins directed against specific intracellular targets, whereas the antitoxins are either proteins or small RNAs that neutralize the toxin or inhibit toxin synthesis. Within the three types of complex, there has been extensive evolutionary shuffling of toxin and antitoxin genes leading to considerable diversity in TA combinations. The intracellular targets of the protein toxins similarly are varied. Numerous toxins, many of which are sequence-specific endoribonucleases, dampen protein synthesis levels in response to a range of stress and nutritional stimuli. Key resources are conserved as a result ensuring the survival of individual cells and therefore the bacterial population. The toxin effects generally are transient and reversible permitting a set of dynamic, tunable responses that reflect environmental conditions. Moreover, by harboring multiple toxins that intercede in protein synthesis in response to different physiological cues, bacteria potentially sense an assortment of metabolic perturbations that are channeled through different TA complexes. Other toxins interfere with the action of topoisomersases, cell wall assembly, or cytoskeletal structures. TAs also play important roles in bacterial persistence, biofilm formation and multidrug tolerance, and have considerable potential both as new components of the genetic toolbox and as targets for novel antibacterial drugs.

  15. Exfoliative toxins of Staphylococcus aureus.

    PubMed

    Bukowski, Michal; Wladyka, Benedykt; Dubin, Grzegorz

    2010-05-01

    Staphylococcus aureus is an important pathogen of humans and livestock. It causes a diverse array of diseases, ranging from relatively harmless localized skin infections to life-threatening systemic conditions. Among multiple virulence factors, staphylococci secrete several exotoxins directly associated with particular disease symptoms. These include toxic shock syndrome toxin 1 (TSST-1), enterotoxins, and exfoliative toxins (ETs). The latter are particularly interesting as the sole agents responsible for staphylococcal scalded skin syndrome (SSSS), a disease predominantly affecting infants and characterized by the loss of superficial skin layers, dehydration, and secondary infections. The molecular basis of the clinical symptoms of SSSS is well understood. ETs are serine proteases with high substrate specificity, which selectively recognize and hydrolyze desmosomal proteins in the skin. The fascinating road leading to the discovery of ETs as the agents responsible for SSSS and the characterization of the molecular mechanism of their action, including recent advances in the field, are reviewed in this article.

  16. An update on uremic toxins.

    PubMed

    Neirynck, N; Vanholder, R; Schepers, E; Eloot, S; Pletinck, A; Glorieux, G

    2013-02-01

    In the last decade, uremic toxicity as a potential cause for the excess of cardiovascular disease and mortality observed in chronic kidney disease gained more and more interest. This review focuses on uremic toxins with known cardiovascular effects and their removal. For protein-bound solutes, for example, indoxylsulfate and the conjugates of p-cresol, and for small water-soluble solutes, for example, guanidines, such as ADMA and SDMA, there is a growing evidence for a role in cardiovascular toxicity in vitro (e.g., affecting leukocyte, endothelial, vascular smooth muscle cell function) and/or in vivo. Several middle molecules (e.g., beta-2-microglobulin, interleukin-6, TNF-alpha and FGF-23) were shown to be predictors for cardiovascular disease and/or mortality. Most of these solutes, however, are difficult to remove during dialysis, which is traditionally assessed by studying the removal of urea, which can be considered as a relatively inert uremic retention solute. However, even the effective removal of other small water-soluble toxins than urea can be hampered by their larger distribution volumes. Middle molecules (beta-2-microglobulin as prototype, but not necessarily representative for others) are cleared more efficiently when the pore size of the dialyzer membrane increases, convection is applied and dialysis time is prolonged. Only adding convection to diffusion improves the removal of protein-bound toxins. Therefore, alternative removal strategies, such as intestinal adsorption, drugs interfering with toxic biochemical pathways or decreasing toxin concentration, and extracorporeal plasma adsorption, as well as kinetic behavior during dialysis need further investigation. Even more importantly, randomized clinical studies are required to demonstrate a survival advantage through these strategies.

  17. Neutralising Antibodies against Ricin Toxin

    PubMed Central

    Prigent, Julie; Panigai, Laetitia; Lamourette, Patricia; Sauvaire, Didier; Devilliers, Karine; Plaisance, Marc; Volland, Hervé; Créminon, Christophe; Simon, Stéphanie

    2011-01-01

    The Centers for Disease Control and Prevention have listed the potential bioweapon ricin as a Category B Agent. Ricin is a so-called A/B toxin produced by plants and is one of the deadliest molecules known. It is easy to prepare and no curative treatment is available. An immunotherapeutic approach could be of interest to attenuate or neutralise the effects of the toxin. We sought to characterise neutralising monoclonal antibodies against ricin and to develop an effective therapy. For this purpose, mouse monoclonal antibodies (mAbs) were produced against the two chains of ricin toxin (RTA and RTB). Seven mAbs were selected for their capacity to neutralise the cytotoxic effects of ricin in vitro. Three of these, two anti-RTB (RB34 and RB37) and one anti-RTA (RA36), when used in combination improved neutralising capacity in vitro with an IC50 of 31 ng/ml. Passive administration of association of these three mixed mAbs (4.7 µg) protected mice from intranasal challenges with ricin (5 LD50). Among those three antibodies, anti-RTB antibodies protected mice more efficiently than the anti-RTA antibody. The combination of the three antibodies protected mice up to 7.5 hours after ricin challenge. The strong in vivo neutralising capacity of this three mAbs combination makes it potentially useful for immunotherapeutic purposes in the case of ricin poisoning or possibly for prevention. PMID:21633505

  18. Novel Class of Spider Toxin

    PubMed Central

    Vassilevski, Alexander A.; Fedorova, Irina M.; Maleeva, Ekaterina E.; Korolkova, Yuliya V.; Efimova, Svetlana S.; Samsonova, Olga V.; Schagina, Ludmila V.; Feofanov, Alexei V.; Magazanik, Lev G.; Grishin, Eugene V.

    2010-01-01

    Venom of the yellow sac spider Cheiracanthium punctorium (Miturgidae) was found unique in terms of molecular composition. Its principal toxic component CpTx 1 (15.1 kDa) was purified, and its full amino acid sequence (134 residues) was established by protein chemistry and mass spectrometry techniques. CpTx 1 represents a novel class of spider toxin with modular architecture. It consists of two different yet homologous domains (modules) each containing a putative inhibitor cystine knot motif, characteristic of the widespread single domain spider neurotoxins. Venom gland cDNA sequencing provided precursor protein (prepropeptide) structures of three CpTx 1 isoforms (a–c) that differ by single residue substitutions. The toxin possesses potent insecticidal (paralytic and lethal), cytotoxic, and membrane-damaging activities. In both fly and frog neuromuscular preparations, it causes stable and irreversible depolarization of muscle fibers leading to contracture. This effect appears to be receptor-independent and is inhibited by high concentrations of divalent cations. CpTx 1 lyses cell membranes, as visualized by confocal microscopy, and destabilizes artificial membranes in a manner reminiscent of other membrane-active peptides by causing numerous defects of variable conductance and leading to bilayer rupture. The newly discovered class of modular polypeptides enhances our knowledge of the toxin universe. PMID:20657014

  19. Removal of cyanobacterial bloom from a biopond-wetland system and the associated response of zoobenthic diversity.

    PubMed

    Wu, Yonghong; Kerr, Philip G; Hu, Zhengyi; Yang, Linzhang

    2010-06-01

    Harmful cyanobacterial bloom in water bodies frequently occurs due to eutrophication, leading to the excessive growth of cyanobacteria which in turn may lead to a decrease in biodiversity. A biopond-wetland system to control cyanobacterial bloom and stabilize or even increase biodiversity is proposed and applied in a pond, Kunming, western China where cyanobacterial blooms frequently break out. The biopond-wetland system examined includes three main parts: filter-feeding fish, replanted pond macrophytes, and a terminal artificial wetland. When the hydraulic load of the biopond-wetland system was 500m(3)/d on non-rainy days, the system successfully decreased the level of chlorophyll-a (Chl-a). The declining levels of total nitrogen (TN), total phosphorus (TP) and ammonia in the water after establishing the biopond-wetland system also coincided with the disappearance of the cyanobacterial bloom. In the second summer, when the biopond-wetland system was in a relatively steady-state condition, the overall average nutrient removal efficiencies were as follows, Chl-a (83%), TN (57%), TP (70%) and ammonia (66%), while in the second winter, the overall average removal efficiencies were Chl-a (66%), TN (40%), TP (53%) and ammonia (49%). Simpson's diversity index of zoobenthos indicated that the system increased the zoobenthic diversity and improved the growth conditions of the zoobenthos habitat. The results demonstrated that the biopond-wetland system could control cyanobacterial blooms.

  20. Bacterial Communities Associated with Four Cyanobacterial Genera Display Structural and Functional Differences: Evidence from an Experimental Approach

    PubMed Central

    Zhu, Lin; Zancarini, Anouk; Louati, Imen; De Cesare, Silvia; Duval, Charlotte; Tambosco, Kevin; Bernard, Cécile; Debroas, Didier; Song, Lirong; Leloup, Julie; Humbert, Jean-François

    2016-01-01

    To overcome the limitations associated with studying the interactions between bacterial communities (BCs) and cyanobacteria in natural environments, we compared the structural and functional diversities of the BCs associated with 15 non-axenic cyanobacterial strains in culture and two natural BCs sampled during cyanobacterial blooms. No significant differences in richness and diversity were found between the natural and cultivated BCs, although some of the cyanobacterial strains had been isolated 11 years earlier. Moreover, these BCs shared some similar characteristics, such as a very low abundance of Actinobacteria, but they display significant differences at the operational taxonomic unit (OTU) level. Overall, our findings suggest that BCs associated with cyanobacteria in culture are good models to better understand the interactions between heterotrophic bacteria and cyanobacteria. Additionally, BCs associated with heterocystous cyanobacterial strains cultivated in Z8X culture medium without nitrate (Aphanizomenon–Dolichospermum) demonstrated significant differences compared to BCs associated with non-heterocystous strains cultivated in Z8 culture medium (Planktothrix–Microcystis) in terms of their composition and their ability to utilize different carbon sources, suggesting the potential influence of cyanobacterial metabolism and/or culture media on associated BCs. Finally, half of the dominant OTUs in these BCs were specifically associated with cyanobacteria or other phytoplankton, whereas the remaining OTUs were generally associated with ecosystems containing high organic matter content, such as sludge or intestines. PMID:27822204

  1. Botulinum toxin to minimize facial scarring.

    PubMed

    Sherris, David A; Gassner, Holger G

    2002-02-01

    Botulinum toxin injection has been used for a variety of indications in humans, including blepharospasm and hyperfunctional facial lines. This article describes a novel formulation of botulinum toxin, which supplies immediate feedback to the injecting physician. Additionally, recent findings are described that indicate the immediate injection of botulinum toxin into the muscles underlying a wound can improve the cosmetic outcome of the facial cutaneous scar. Future applications of these findings are discussed.

  2. Medical Defense Against Protein Toxin Weapons

    DTIC Science & Technology

    2004-10-01

    greatly expanded the accessible delivery vehicles for protein toxins to include, for example, natural or genetically modified bacteria and engineered...01 OCT 2004 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Medical defense against protein toxin weapons: review and perspective...SUPPLEMENTARY NOTES 14. ABSTRACT The term " toxin weapon" has been used to describe poisons, classically of natural origin but increasingly

  3. Dinoflagellate Toxins Responsible for Ciguatera Food Poisoning

    DTIC Science & Technology

    1987-12-10

    AD____ AD-A 194 466 DNOFLACU.ATh TOXINS RESIONSIBLE FOR CIGUATERA FOOD POISONING Annual Summary Report 0 Donald M. Miller 10 December 1987 Supported...21701-5012 62770A 162770A87] AA 7 7 A11. TITLE (Include Security Classification) DINOFLAGELLATE TOXINS RESPONSIBLE FOR CIGUATERA FOOD POISONING .12...occurring in humans who have become intoxicated from eating poison fish. Fish spontaneously accumulate the toxin through the food chain or directly from

  4. Anti-Idiotype Probes for Toxin Detection

    DTIC Science & Technology

    1991-09-13

    used for polyclonal and mono- clonal antibody production . We have identified proteins on the cell surface of thymocytes that bind to exfoliative Toxin A...of toxins represents the novel aspect of this proposal. It will rely upon the production of anti-idiotypic antibodies to the receptor molecules. Such...specifically Ser-197 results in loss of biological activity suggests that the toxins may autodigest. This has yet to be proven. AnOibody Production At about the

  5. Cellular and Systemic Effects of Anthrax Lethal Toxin and Edema Toxin

    PubMed Central

    Moayeri, Mahtab; Leppla, Stephen H.

    2009-01-01

    Anthrax lethal toxin (LT) and edema toxin (ET) are the major virulence factors of anthrax and can replicate the lethality and symptoms associated with the disease. This review provides an overview of our current understanding of anthrax toxin effects in animal models and the cytotoxicity (necrosis and apoptosis) induced by LT in different cells. A brief reexamination of early historic findings on toxin in vivo effects in the context of our current knowledge is also presented. PMID:19638283

  6. Light Regimes Shape Utilization of Extracellular Organic C and N in a Cyanobacterial Biofilm

    PubMed Central

    Stuart, Rhona K.; Mayali, Xavier; Boaro, Amy A.; Zemla, Adam; Everroad, R. Craig; Nilson, Daniel; Weber, Peter K.; Lipton, Mary; Bebout, Brad M.; Pett-Ridge, Jennifer

    2016-01-01

    ABSTRACT Although it is becoming clear that many microbial primary producers can also play a role as organic consumers, we know very little about the metabolic regulation of photoautotroph organic matter consumption. Cyanobacteria in phototrophic biofilms can reuse extracellular organic carbon, but the metabolic drivers of extracellular processes are surprisingly complex. We investigated the metabolic foundations of organic matter reuse by comparing exoproteome composition and incorporation of 13C-labeled and 15N-labeled cyanobacterial extracellular organic matter (EOM) in a unicyanobacterial biofilm incubated using different light regimes. In the light and the dark, cyanobacterial direct organic C assimilation accounted for 32% and 43%, respectively, of all organic C assimilation in the community. Under photosynthesis conditions, we measured increased excretion of extracellular polymeric substances (EPS) and proteins involved in micronutrient transport, suggesting that requirements for micronutrients may drive EOM assimilation during daylight hours. This interpretation was supported by photosynthesis inhibition experiments, in which cyanobacteria incorporated N-rich EOM-derived material. In contrast, under dark, C-starved conditions, cyanobacteria incorporated C-rich EOM-derived organic matter, decreased excretion of EPS, and showed an increased abundance of degradative exoproteins, demonstrating the use of the extracellular domain for C storage. Sequence-structure modeling of one of these exoproteins predicted a specific hydrolytic activity that was subsequently detected, confirming increased EOM degradation in the dark. Associated heterotrophic bacteria increased in abundance and upregulated transport proteins under dark relative to light conditions. Taken together, our results indicate that biofilm cyanobacteria are successful competitors for organic C and N and that cyanobacterial nutrient and energy requirements control the use of EOM. PMID:27353754

  7. A PCR technique based on the Hip1 interspersed repetitive sequence distinguishes cyanobacterial species and strains.

    PubMed

    Smith, J K; Parry, J D; Day, J G; Smith, R J

    1998-10-01

    The use of primers based on the Hip1 sequence as a typing technique for cyanobacteria has been investigated. The discovery of short repetitive sequence structures in bacterial DNA during the last decade has led to the development of PCR-based methods for typing, i.e., distinguishing and identifying, bacterial species and strains. An octameric palindromic sequence known as Hip1 has been shown to be present in the chromosomal DNA of many species of cyanobacteria as a highly repetitious interspersed sequence. PCR primers were constructed that extended the Hip1 sequence at the 3' end by two bases. Five of the 16 possible extended primers were tested. Each of the five primers produced a different set of products when used to prime PCR from cyanobacterial genomic DNA. Each primer produced a distinct set of products for each of the 15 cyanobacterial species tested. The ability of Hip1-based PCR to resolve taxonomic differences was assessed by analysis of independent isolates of Anabaena flos-aquae and Nostoc ellipsosporum obtained from the CCAP (Culture Collection of Algae and Protozoa, IFE, Cumbria, UK). A PCR-based RFLP analysis of products amplified from the 23S-16S rDNA intergenic region was used to characterize the isolates and to compare with the Hip1 typing data. The RFLP and Hip1 typing yielded similar results and both techniques were able to distinguish different strains. On the basis of these results it is suggested that the Hip1 PCR technique may assist in distinguishing cyanobacterial species and strains.

  8. Simulating cyanobacterial phenotypes by integrating flux balance analysis, kinetics, and a light distribution function

    SciTech Connect

    He, Lian; Wu, Stephen G.; Wan, Ni; Reding, Adrienne C.; Tang, Yinjie J.

    2015-12-24

    In this study, genome-scale models (GSMs) are widely used to predict cyanobacterial phenotypes in photobioreactors (PBRs). However, stoichiometric GSMs mainly focus on fluxome that result in maximal yields. Cyanobacterial metabolism is controlled by both intracellular enzymes and photobioreactor conditions. To connect both intracellular and extracellular information and achieve a better understanding of PBRs productivities, this study integrates a genome-scale metabolic model of Synechocystis 6803 with growth kinetics, cell movements, and a light distribution function. The hybrid platform not only maps flux dynamics in cells of sub-populations but also predicts overall production titer and rate in PBRs. Analysis of the integrated GSM demonstrates several results. First, cyanobacteria are capable of reaching high biomass concentration (>20 g/L in 21 days) in PBRs without light and CO2 mass transfer limitations. Second, fluxome in a single cyanobacterium may show stochastic changes due to random cell movements in PBRs. Third, insufficient light due to cell self-shading can activate the oxidative pentose phosphate pathway in subpopulation cells. Fourth, the model indicates that the removal of glycogen synthesis pathway may not improve cyanobacterial bio-production in large-size PBRs, because glycogen can support cell growth in the dark zones. Based on experimental data, the integrated GSM estimates that Synechocystis 6803 in shake flask conditions has a photosynthesis efficiency of ~2.7 %. Conclusions: The multiple-scale integrated GSM, which examines both intracellular and extracellular domains, can be used to predict production yield/rate/titer in large-size PBRs. More importantly, genetic engineering strategies predicted by a traditional GSM may work well only in optimal growth conditions. In contrast, the integrated GSM may reveal mutant physiologies in diverse bioreactor conditions, leading to the design of robust strains with high

  9. Flavodiiron proteins Flv1 and Flv3 enable cyanobacterial growth and photosynthesis under fluctuating light

    PubMed Central

    Allahverdiyeva, Yagut; Mustila, Henna; Ermakova, Maria; Bersanini, Luca; Richaud, Pierre; Ajlani, Ghada; Battchikova, Natalia; Cournac, Laurent; Aro, Eva-Mari

    2013-01-01

    Cyanobacterial flavodiiron proteins (FDPs; A-type flavoprotein, Flv) comprise, besides the β-lactamase–like and flavodoxin domains typical for all FDPs, an extra NAD(P)H:flavin oxidoreductase module and thus differ from FDPs in other Bacteria and Archaea. Synechocystis sp. PCC 6803 has four genes encoding the FDPs. Flv1 and Flv3 function as an NAD(P)H:oxygen oxidoreductase, donating electrons directly to O2 without production of reactive oxygen species. Here we show that the Flv1 and Flv3 proteins are crucial for cyanobacteria under fluctuating light, a typical light condition in aquatic environments. Under constant-light conditions, regardless of light intensity, the Flv1 and Flv3 proteins are dispensable. In contrast, under fluctuating light conditions, the growth and photosynthesis of the Δflv1(A) and/or Δflv3(A) mutants of Synechocystis sp. PCC 6803 and Anabaena sp. PCC 7120 become arrested, resulting in cell death in the most severe cases. This reaction is mainly caused by malfunction of photosystem I and oxidative damage induced by reactive oxygen species generated during abrupt short-term increases in light intensity. Unlike higher plants that lack the FDPs and use the Proton Gradient Regulation 5 to safeguard photosystem I, the cyanobacterial homolog of Proton Gradient Regulation 5 is shown not to be crucial for growth under fluctuating light. Instead, the unique Flv1/Flv3 heterodimer maintains the redox balance of the electron transfer chain in cyanobacteria and provides protection for photosystem I under fluctuating growth light. Evolution of unique cyanobacterial FDPs is discussed as a prerequisite for the development of oxygenic photosynthesis. PMID:23431195

  10. Effects of Light Stress on Extracellular Cycling in a Cyanobacterial Biofilm Community

    NASA Astrophysics Data System (ADS)

    Stuart, R.; Mayali, X.; Pett-Ridge, J.; Weber, P. K.; Thelen, M.; Bebout, B.; Lipton, M. S.

    2015-12-01

    Cyanobacterial carbon excretion is crucial to carbon cycling in many microbial communities, but the nature and bioavailability of the carbon excreted is dependent on physiological function, which is often unknown. Cyanobacteria are the dominant primary producers in hypersaline mats and there is large reservoir of carbon in the extracellular matrix, but the nature and flux is understudied. In a previous study, we examined the macromolecular composition of the matrix of microbial mats from Elkhorn Slough in Monterey Bay, California and a unicyanobacterial culture, ESFC-1, isolated from the those mats, and found evidence for cyanobacterial degradation and re-uptake of extracellular organic matter. In this work, we further explore mechanisms of this degradation and re-uptake by examining effects of light using a combination of high-resolution imaging mass spectrometry (NanoSIMS) and metaproteomics of extracellular proteins. Based on these findings, we propose that mat Cyanobacteria store and recycle organic material from the mat extracellular matrix. Cyanobacteria can account for 70-90% of the biomass in the upper phototrophic layer of the mats, so their re-uptake of organic carbon and nitrogen has the potential to re-define organic matter availability in these systems. This work has implications for cyanobacterial adaptation to dynamic environments like microbial mats, where uptake of carbon and nitrogen in variable forms may be necessary to persist. This research was supported by the U.S. Department of Energy Office of Science, Office of Biological and Environmental Research Genomic Science program under FWP SCW1039. Work at LLNL was performed under the auspices of the U.S. Department of Energy under Contract DE-AC52-07NA27344.

  11. Avian vacuolar myelinopathy linked to exotic aquatic plants and a novel cyanobacterial species.

    PubMed

    Wilde, Susan B; Murphy, Thomas M; Hope, Charlotte P; Habrun, Sarah K; Kempton, Jason; Birrenkott, Anna; Wiley, Faith; Bowerman, William W; Lewitus, Alan J

    2005-06-01

    Invasions of exotic species have created environmental havoc through competition and displacement of native plants and animals. The introduction of hydrilla (Hydrilla verticillata) into the United States in the 1960s has been detrimental to navigation, power generation, water intake, and water quality (McCann et al., 1996). Our field surveys and feeding studies have now implicated exotic hydrilla and associated epiphytic cyanobacterial species as a link to avian vacuolar myelinopathy (AVM), an emerging avian disease affecting herbivorous waterbirds and their avian predators. AVM, first reported in 1994, has caused the death of at least 100 bald eagles (Haliaeetus leucocephalus) and thousands of American coots (Fulica americana) at 11 sites from Texas to North Carolina (Thomas et al., 1998; Rocke et al., 2002). Our working hypothesis is that the agent of this disease is an uncharacterized neurotoxin produced by a novel cyanobacterial epiphyte of the order Stigonematales. This undescribed species covers up to 95% of the surface area of leaves in reservoirs where bird deaths have occurred from the disease. In addition, this species is rare or not found on hydrilla collected at sites where AVM disease has not been diagnosed. Laboratory feeding trials and a sentinel bird study using naturally occurring blooms of cyanobacteria on hydrilla leaves and farm-raised mallard ducks (Anas platyrhynchos) induced the disease experimentally. Since 1994 AVM has been diagnosed in additional sites from Texas to North Carolina. Specific site characteristics that produce the disjunct distribution of AVM are unknown, but it is probable that the incidence of this disease will increase with the introduction of hydrilla and associated cyanobacterial species into additional ponds, lakes, and reservoirs.

  12. Simulating cyanobacterial phenotypes by integrating flux balance analysis, kinetics, and a light distribution function

    DOE PAGES

    He, Lian; Wu, Stephen G.; Wan, Ni; ...

    2015-12-24

    In this study, genome-scale models (GSMs) are widely used to predict cyanobacterial phenotypes in photobioreactors (PBRs). However, stoichiometric GSMs mainly focus on fluxome that result in maximal yields. Cyanobacterial metabolism is controlled by both intracellular enzymes and photobioreactor conditions. To connect both intracellular and extracellular information and achieve a better understanding of PBRs productivities, this study integrates a genome-scale metabolic model of Synechocystis 6803 with growth kinetics, cell movements, and a light distribution function. The hybrid platform not only maps flux dynamics in cells of sub-populations but also predicts overall production titer and rate in PBRs. Analysis of the integratedmore » GSM demonstrates several results. First, cyanobacteria are capable of reaching high biomass concentration (>20 g/L in 21 days) in PBRs without light and CO2 mass transfer limitations. Second, fluxome in a single cyanobacterium may show stochastic changes due to random cell movements in PBRs. Third, insufficient light due to cell self-shading can activate the oxidative pentose phosphate pathway in subpopulation cells. Fourth, the model indicates that the removal of glycogen synthesis pathway may not improve cyanobacterial bio-production in large-size PBRs, because glycogen can support cell growth in the dark zones. Based on experimental data, the integrated GSM estimates that Synechocystis 6803 in shake flask conditions has a photosynthesis efficiency of ~2.7 %. Conclusions: The multiple-scale integrated GSM, which examines both intracellular and extracellular domains, can be used to predict production yield/rate/titer in large-size PBRs. More importantly, genetic engineering strategies predicted by a traditional GSM may work well only in optimal growth conditions. In contrast, the integrated GSM may reveal mutant physiologies in diverse bioreactor conditions, leading to the design of robust strains with high chances of success in

  13. Genotoxicity of cyanobacterial extracts containing microcystins from Polish water reservoirs as determined by SOS chromotest and comet assay.

    PubMed

    Mankiewicz, Joanna; Walter, Zofia; Tarczynska, Malgorzata; Palyvoda, Olena; Wojtysiak-Staniaszczyk, Magdalena; Zalewski, Maciej

    2002-01-01

    Toxicity of cyanobacterial blooms, an increasing problem around the world, is connected to the increase in bloom samples containing microcystins, caused by excessive eutrophication of drinking- and recreational water reservoirs. Microcystins are the most common group of cyanobacterial hepatotoxins. In Poland they are produced mainly by the Microcystis genus. The toxicity of microcystins has been well documented, but investigation into their genotoxicity has been insufficient relative to the study of their overall toxicity. Therefore, the aim of this study was the estimation and comparison of the genotoxicity of cyanobacterial extracts with microcystins (CEMs) using the SOS chromotest (bacterial test) with Escherichia coli PQ37 and the comet assay with human lymphocytes. Cyanobacterial bloom samples were collected in the summer months from two Polish water reservoirs, one at Sulejów and one at Jeziorsko. The SOS chromotest, which used prokaryotic cells (without metabolic activation), and the comet assay, which used eukaryotic cells, both indicated the potential genotoxic effect of CEMs. Cyanobacterial extracts caused DNA damage in human lymphocytes in vitro. The maximum level of DNA damage was observed after 12 h incubation with CEMs. The bacterial test indicated a dependence of the degree of CEM genotoxicity, the composition, and the concentration of microcystins in each bloom sample examined with the time of exposure. Differences between the genotoxicity of cyanobacterial extract and the standard microcystin-LR were noticeable. This was probably caused by the interaction of different microcystin variants. The results showed that CEMs from Polish water reservoirs were genotoxic, which was reflected by the stimulation of the SOS repair system in bacterial cells (SOS chromotest) and by the damage induced in DNA in human lymphocytes (comet assay).

  14. Seasonal variation in nifH abundance and expression of cyanobacterial communities associated with boreal feather mosses

    PubMed Central

    Warshan, Denis; Bay, Guillaume; Nahar, Nurun; Wardle, David A; Nilsson, Marie-Charlotte; Rasmussen, Ulla

    2016-01-01

    Dinitrogen (N2)-fixation by cyanobacteria living in symbiosis with pleurocarpous feather mosses (for example, Pleurozium schreberi and Hylocomium splendens) represents the main pathway of biological N input into N-depleted boreal forests. Little is known about the role of the cyanobacterial community in contributing to the observed temporal variability of N2-fixation. Using specific nifH primers targeting four major cyanobacterial clusters and quantitative PCR, we investigated how community composition, abundance and nifH expression varied by moss species and over the growing seasons. We evaluated N2-fixation rates across nine forest sites in June and September and explored the abundance and nifH expression of individual cyanobacterial clusters when N2-fixation is highest. Our results showed temporal and host-dependent variations of cyanobacterial community composition, nifH gene abundance and expression. N2-fixation was higher in September than June for both moss species, explained by higher nifH gene expression of individual clusters rather than higher nifH gene abundance or differences in cyanobacterial community composition. In most cases, ‘Stigonema cluster' made up less than 29% of the total cyanobacterial community, but accounted for the majority of nifH gene expression (82–94% of total nifH expression), irrespective of sampling date or moss species. Stepwise multiple regressions showed temporal variations in N2-fixation being greatly explained by variations in nifH expression of the ‘Stigonema cluster'. These results suggest that Stigonema is potentially the most influential N2-fixer in symbiosis with boreal forest feather mosses. PMID:26918665

  15. Engineering Cyanobacterial Cell Morphology for Enhanced Recovery and Processing of Biomass.

    PubMed

    Jordan, Adam; Chandler, Jenna; MacCready, Joshua S; Huang, Jingcheng; Osteryoung, Katherine W; Ducat, Daniel C

    2017-02-24

    Cyanobacteria are emerging as alternative crop species for the production of fuels, chemicals, and biomass. Yet, the success of these microbes depends upon the development of cost-effective technologies that permit scaled cultivation and cell harvesting. Here, we investigate the feasibility of engineering cell morphology in order to improve biomass recovery and decrease energetic costs associated with lysing cyanobacterial cells. Specifically, we modify the levels of Min system proteins in Synechococcus elongatus sp. PCC 7942. The Min system has established functions in controlling cell division by regulating assembly of FtsZ, a tubulin-like protein required to define the bacterial division plane. We show that altering expression of two FtsZ-regulatory proteins, MinC and Cdv3, permits control over cell morphology by disrupting FtsZ localization and cell division, without preventing continued cell growth. By varying the expression of these proteins, we can tune the length of cyanobacterial cells across a broad dynamic range: anywhere from a ∼20% increased length relative to wildtype to near-millimeter lengths. Highly elongated cells exhibit increased rates of sedimentation under low centrifugal forces or by gravity-assisted settling. Furthermore, hyperelongated cells are also more susceptible to lysis through the application of mild physical stress. Collectively, these results demonstrate a novel approach towards decreasing harvesting and processing costs associated with mass cyanobacterial cultivation through altering morphology at the cellular level.Importance: We show that the cell length of a model cyanobacterial species can be programmed through the rational manipulation of expression of protein factors that suppress cell division. In some instances, we are able to increase the size of these cells to near millimeter lengths through this approach. The resulting elongated cells have favorable properties with regard to cell harvesting and lysis. Furthermore

  16. Large plasmonic fluorescence enhancement of cyanobacterial photosystem I coupled to silver island films

    NASA Astrophysics Data System (ADS)

    Czechowski, N.; Lokstein, H.; Kowalska, D.; Ashraf, K.; Cogdell, R. J.; Mackowski, S.

    2014-07-01

    A large, two-orders-of-magnitude enhancement of fluorescence emission from cyanobacterial Photosystem I (PSI) coupled to plasmonic excitations in silver island films was observed. Such a high value has not been reported for metal-enhanced fluorescence of photosynthetic pigment-protein complexes before. The dramatic enhancement of the PSI emission occurs when PSI is excited resonantly into the Qx and Qy bands of chlorophyll a. In contrast, excitation in the carotenoid absorption band yields ten times lower enhancement factors. We attribute these large values of enhancement factor to plasmon-induced activation of excitation and emission channels absent for isolated PSI complexes.

  17. Freshwater cyanobacterial blooms and primary liver cancer epidemiological studies in Serbia.

    PubMed

    Svircev, Zorica; Krstic, Svetislav; Miladinov-Mikov, Marica; Baltic, Vladimir; Vidovic, Milka

    2009-01-01

    A large part of Central Serbia experiences continual shortage of sufficient ground water resources. For that reason, more than 20 reservoirs serve as drinking water suppliers. Significant and persistent cyanobacterial "blooms" have been recognized in nine of them. Samples for cyanotoxin analyses were taken during and after "blooms" in Celije Reservoir and from Krusevac town-supplied tap water from that reservoir two days later. Concentration of microcystin-LR was 650 microg L(-1) in the reservoir, while the tap water contained 2.5 microg L(-1). In the two investigated periods, the high primary liver cancer (PLC) mortality of 11.6 from 1980-1990 and extremely high PLC incidence of 34.7 from 2000-2002 were observed in the regions affected by heavy cyanobacterial "blooms." In contrast, PLC mortality and incidence rates were substantially lower in the regions not affected by cyanobacterial blooms: in 1980-1990 the rate of PLC mortality amounted to 2.7 in Kosovo, 7.6 in Vojvodina, and 8.3 in the non-affected regions of Central Serbia; while in 2000-2002 PLC incidence amounted to 4.1 in Kosovo, 5.2 in Vojvodina, and 13.6 in the non- or less-affected regions of Central Serbia. Keeping in mind that the most affected PLC regions in Central Serbia (Toplicki, Niski, and Sumadijski regions) have the water supply systems based on six reservoirs found regularly in bloom during summer months and that some of the regions are also connected with two boundary "blooming" reservoirs, representing a total of eight of nine blooming reservoirs, it is easy to presume that the PLC incidence could be related to drinking water quality. The uneven geographic distribution of liver cancer in Serbia is conspicuous and hot spots could be related to drinking water supply. It is very clear that the high-risk regions for PLC occurrence correspond with drinking water reservoirs continually found with cyanobacterial blooms, and the low risk regions correspond with water supplies not affected by

  18. Dynamics of cyanobacterial bloom formation during short-term hydrodynamic fluctuation in a large shallow, eutrophic, and wind-exposed Lake Taihu, China.

    PubMed

    Wu, Tingfeng; Qin, Boqiang; Zhu, Guangwei; Luo, Liancong; Ding, Yanqing; Bian, Geya

    2013-12-01

    Short-term hydrodynamic fluctuations caused by extreme weather events are expected to increase worldwide because of global climate change, and such fluctuations can strongly influence cyanobacterial blooms. In this study, the cyanobacterial bloom disappearance and reappearance in Lake Taihu, China, in response to short-term hydrodynamic fluctuations, was investigated by field sampling, long-term ecological records, high-frequency sensors and MODIS satellite images. The horizontal drift caused by the dominant easterly wind during the phytoplankton growth season was mainly responsible for cyanobacterial biomass accumulation in the western and northern regions of the lake and subsequent bloom formation over relatively long time scales. The cyanobacterial bloom changed slowly under calm or gentle wind conditions. In contrast, the short-term bloom events within a day were mainly caused by entrainment and disentrainment of cyanobacterial colonies by wind-induced hydrodynamics. Observation of a westerly event in Lake Taihu revealed that when the 30 min mean wind speed (flow speed) exceeded the threshold value of 6 m/s (5.7 cm/s), cyanobacteria in colonies were entrained by the wind-induced hydrodynamics. Subsequently, the vertical migration of cyanobacterial colonies was controlled by hydrodynamics, resulting in thorough mixing of algal biomass throughout the water depth and the eventual disappearance of surface blooms. Moreover, the intense mixing can also increase the chance for forming larger and more cyanobacterial colonies, namely, aggregation. Subsequently, when the hydrodynamics became weak, the cyanobacterial colonies continuously float upward without effective buoyancy regulation, and cause cyanobacterial bloom explosive expansion after the westerly. Furthermore, the results of this study indicate that the strong wind happening frequently during April and October can be an important cause of the formation and expansion of cyanobacterial blooms in Lake Taihu.

  19. Synthesis and biology of cyclic imine toxins, an emerging class of potent, globally distributed marine toxins.

    PubMed

    Stivala, Craig E; Benoit, Evelyne; Aráoz, Rómulo; Servent, Denis; Novikov, Alexei; Molgó, Jordi; Zakarian, Armen

    2015-03-01

    From a small group of exotic compounds isolated only two decades ago, Cyclic Imine (CI) toxins have become a major class of marine toxins with global distribution. Their distinct chemical structure, biological mechanism of action, and intricate chemistry ensures that CI toxins will continue to be the subject of fascinating fundamental studies in the broad fields of chemistry, chemical biology, and toxicology. The worldwide occurrence of potent CI toxins in marine environments, their accumulation in shellfish, and chemical stability are important considerations in assessing risk factors for human health. This review article aims to provide an account of chemistry, biology, and toxicology of CI toxins from their discovery to the present day.

  20. Botulinum toxin: The Midas touch

    PubMed Central

    Shilpa, P. S.; Kaul, Rachna; Sultana, Nishat; Bhat, Suraksha

    2014-01-01

    Botulinum Toxin (BT) is a natural molecule produced during growth and autolysis of bacterium called Clostridium botulinum. Use of BT for cosmetic purposes has gained popularity over past two decades, and recently, other therapeutic uses of BT has been extensively studied. BT is considered as a minimally invasive agent that can be used in the treatment of various orofacial disorders and improving the quality of life in such patients. The objective of this article is to review the nature, mechanism of action of BT, and its application in various head and neck diseases. PMID:24678189

  1. Burn sepsis and burn toxin

    PubMed Central

    Allgöwer, Martin; Städtler, Karl; Schoenenberger, Guido A

    1974-01-01

    The salient steps of a 20-year programme of research into the nature of burn disease are described. By burn disease we mean the late mortality and morbidity following burns. We have isolated a burn toxin which is derived from a thermal polymerization of cell membrane lipoproteins within the dermis and have studied its influence on the effects of sepsis. We have also used it in the development of active and passive immunization therapy of severe burns. ImagesFig. 2Fig. 5Fig. 6Fig. 7Fig. 8Fig. 9 PMID:4429330

  2. Designing Inhibitors of Anthrax Toxin

    PubMed Central

    Nestorovich, Ekaterina M.; Bezrukov, Sergey M.

    2014-01-01

    Introduction Present-day rational drug design approaches are based on exploiting unique features of the target biomolecules, small- or macromolecule drug candidates, and physical forces that govern their interactions. The 2013 Nobel Prize in chemistry awarded “for the development of multiscale models for complex chemical systems” once again demonstrated the importance of the tailored drug discovery that reduces the role of the trial and error approach to a minimum. The “rational drug design” term is rather comprehensive as it includes all contemporary methods of drug discovery where serendipity and screening are substituted by the information-guided search for new and existing compounds. Successful implementation of these innovative drug discovery approaches is inevitably preceded by learning the physics, chemistry, and physiology of functioning of biological structures under normal and pathological conditions. Areas covered This article provides an overview of the recent rational drug design approaches to discover inhibitors of anthrax toxin. Some of the examples include small-molecule and peptide-based post-exposure therapeutic agents as well as several polyvalent compounds. The review also directs the reader to the vast literature on the recognized advances and future possibilities in the field. Expert opinion Existing options to combat anthrax toxin lethality are limited. With the only anthrax toxin inhibiting therapy (PA-targeting with a monoclonal antibody, raxibacumab) approved to treat inhalational anthrax, in our view, the situation is still insecure. The FDA’s animal rule for drug approval, which clears compounds without validated efficacy studies on humans, creates a high level of uncertainty, especially when a well-characterized animal model does not exist. Besides, unlike PA, which is known to be unstable, LF remains active in cells and in animal tissues for days. Therefore, the effectiveness of the post-exposure treatment of the individuals

  3. Multifunctional-autoprocessing repeats-in-toxin (MARTX) Toxins of Vibrios

    PubMed Central

    Satchell, Karla J. F.

    2015-01-01

    Multifunctional-autoprocessing repeats-in-toxin (MARTX) toxins are a heterogeneous group of toxins found in a number of Vibrio species and other Gram-negative bacteria. The toxins are composed of conserved repeat regions and an autoprocessing protease domain that together function as a delivery platform for transfer of cytotoxic and cytopathic domains into target eukaryotic cell cytosol. Within the cells, the effectors can alter biological processes such as signaling or cytoskeletal structure, presumably to the benefit of the bacterium. Ten effector domains are found in the various Vibrio MARTX toxins, although any one toxin carries only two to five effector domains. The specific toxin variant expressed by a species can be modified by homologous recombination to acquire or lose effector domains, such that different strains within the same species can express distinct variants of the toxins. This review examines the conserved structural elements of the MARTX toxins and details the different toxin arrangements carried by Vibrio species and strains. The catalytic function of domains and how the toxins are linked to pathogenesis of human and animals is described. PMID:26185092

  4. Stool Test: C. Difficile Toxin (For Parents)

    MedlinePlus

    ... Your 1- to 2-Year-Old Stool Test: C. Difficile Toxin KidsHealth > For Parents > Stool Test: C. Difficile Toxin A A A What's in this ... Questions en español Muestra de materia fecal: toxina C. difficile What It Is A stool (feces) sample ...

  5. The Ins and Outs of Anthrax Toxin

    PubMed Central

    Friebe, Sarah; van der Goot, F. Gisou; Bürgi, Jérôme

    2016-01-01

    Anthrax is a severe, although rather rare, infectious disease that is caused by the Gram-positive, spore-forming bacterium Bacillus anthracis. The infectious form is the spore and the major virulence factors of the bacterium are its poly-γ-D-glutamic acid capsule and the tripartite anthrax toxin. The discovery of the anthrax toxin receptors in the early 2000s has allowed in-depth studies on the mechanisms of anthrax toxin cellular entry and translocation from the endocytic compartment to the cytoplasm. The toxin generally hijacks the endocytic pathway of CMG2 and TEM8, the two anthrax toxin receptors, in order to reach the endosomes. From there, the pore-forming subunit of the toxin inserts into endosomal membranes and enables translocation of the two catalytic subunits. Insertion of the pore-forming unit preferentially occurs in intraluminal vesicles rather than the limiting membrane of the endosome, leading to the translocation of the enzymatic subunits in the lumen of these vesicles. This has important consequences that will be discussed. Ultimately, the toxins reach the cytosol where they act on their respective targets. Target modification has severe consequences on cell behavior, in particular on cells of the immune system, allowing the spread of the bacterium, in severe cases leading to host death. Here we will review the literature on anthrax disease with a focus on the structure of the toxin, how it enters cells and its immunological effects. PMID:26978402

  6. [Axillary hyperhidrosis, botulinium A toxin treatment: Review].

    PubMed

    Clerico, C; Fernandez, J; Camuzard, O; Chignon-Sicard, B; Ihrai, T

    2016-02-01

    Injection of type A botulinum toxin in the armpits is a temporary treatment for axillary hyperhidrosis. This technique described in 1996 by Bushara et al., is known to be efficient and safe. The purpose of this article was to review the data concerning the treatment of axillary hyperhidrosis with botulinum toxin type A, and discuss the other treatment modalities for this socially disabling entity.

  7. Dermatitis from purified sea algae toxin (debromoaplysiatoxin).

    PubMed

    Solomon, A E; Stoughton, R B

    1978-09-01

    Cutaneous inflammation was induced by debromoaplysiatoxin, a purified toxin extracted from Lyngbya majuscula Gomont. This alga causes a seaweed dermatitis that occurs in persons who have swum off the coast of Oahu in Hawaii. By topical application, the toxin was found to produce an irritant pustular folliculitis in humans and to cause a severe cutaneous inflammatory reaction in the rabbit and in hairless mice.

  8. Botulinum Toxin and Gastrointestinal Tract Disorders

    PubMed Central

    Weiser, Kirsten; Kennedy, Abigail

    2008-01-01

    The history of botulinum toxin is fascinating. First recognized as the cause of botulism nearly 200 years ago, it was originally feared as a deadly poison. Over the last 30 years, however, botulinum toxin has been transformed into a readily available medication used to treat a variety of medical disorders. Interest in the use of botulinum toxin has been particularly strong for patients with spastic smooth muscle disorders of the gastrointestinal tract. Patients with achalasia, diffuse esophageal spasm, gastroparesis, sphincter of Oddi dysfunction, and anal fissures have all been treated with botulinum toxin injections, often with impressive results. However, not all patients respond to botulinum toxin therapy, and large randomized controlled trials are lacking for many conditions commonly treated with botulinum toxin. This paper reviews the history, microbiology, and pharmacology of botulinum toxin, discusses its mechanism of action, and then presents recent evidence from the literature regarding the use of botulinum toxin for the treatment of a variety of gastrointestinal tract disorders. PMID:21960915

  9. Target-Driven Evolution of Scorpion Toxins.

    PubMed

    Zhang, Shangfei; Gao, Bin; Zhu, Shunyi

    2015-10-07

    It is long known that peptide neurotoxins derived from a diversity of venomous animals evolve by positive selection following gene duplication, yet a force that drives their adaptive evolution remains a mystery. By using maximum-likelihood models of codon substitution, we analyzed molecular adaptation in scorpion sodium channel toxins from a specific species and found ten positively selected sites, six of which are located at the core-domain of scorpion α-toxins, a region known to interact with two adjacent loops in the voltage-sensor domain (DIV) of sodium channels, as validated by our newly constructed computational model of toxin-channel complex. Despite the lack of positive selection signals in these two loops, they accumulated extensive sequence variations by relaxed purifying selection in prey and predators of scorpions. The evolutionary variability in the toxin-bound regions of sodium channels indicates that accelerated substitutions in the multigene family of scorpion toxins is a consequence of dealing with the target diversity. This work presents an example of atypical co-evolution between animal toxins and their molecular targets, in which toxins suffered from more prominent selective pressure from the channels of their competitors. Our discovery helps explain the evolutionary rationality of gene duplication of toxins in a specific venomous species.

  10. Stool Test: C. Difficile Toxin (For Parents)

    MedlinePlus

    ... Your 1- to 2-Year-Old Stool Test: C. Difficile Toxin KidsHealth > For Parents > Stool Test: C. Difficile Toxin Print A A A What's in ... Questions en español Muestra de materia fecal: toxina C. difficile What It Is A stool (feces) sample ...

  11. Plant Insecticidal Toxins in Ecological Networks

    PubMed Central

    Ibanez, Sébastien; Gallet, Christiane; Després, Laurence

    2012-01-01

    Plant secondary metabolites play a key role in plant-insect interactions, whether constitutive or induced, C- or N-based. Anti-herbivore defences against insects can act as repellents, deterrents, growth inhibitors or cause direct mortality. In turn, insects have evolved a variety of strategies to act against plant toxins, e.g., avoidance, excretion, sequestration and degradation of the toxin, eventually leading to a co-evolutionary arms race between insects and plants and to co-diversification. Anti-herbivore defences also negatively impact mutualistic partners, possibly leading to an ecological cost of toxin production. However, in other cases toxins can also be used by plants involved in mutualistic interactions to exclude inadequate partners and to modify the cost/benefit ratio of mutualism to their advantage. When considering the whole community, toxins have an effect at many trophic levels. Aposematic insects sequester toxins to defend themselves against predators. Depending on the ecological context, toxins can either increase insects’ vulnerability to parasitoids and entomopathogens or protect them, eventually leading to self-medication. We conclude that studying the community-level impacts of plant toxins can provide new insights into the synthesis between community and evolutionary ecology. PMID:22606374

  12. Brown spider dermonecrotic toxin directly induces nephrotoxicity

    SciTech Connect

    Chaim, Olga Meiri; Sade, Youssef Bacila; Bertoni da Silveira, Rafael; Toma, Leny; Kalapothakis, Evanguedes; Chavez-Olortegui, Carlos; Mangili, Oldemir Carlos; Gremski, Waldemiro; Dietrich, Carl Peter von; Nader, Helena B.; Sanches Veiga, Silvio . E-mail: veigass@ufpr.br

    2006-02-15

    Brown spider (Loxosceles genus) venom can induce dermonecrotic lesions at the bite site and systemic manifestations including fever, vomiting, convulsions, disseminated intravascular coagulation, hemolytic anemia and acute renal failure. The venom is composed of a mixture of proteins with several molecules biochemically and biologically well characterized. The mechanism by which the venom induces renal damage is unknown. By using mice exposed to Loxosceles intermedia recombinant dermonecrotic toxin (LiRecDT), we showed direct induction of renal injuries. Microscopic analysis of renal biopsies from dermonecrotic toxin-treated mice showed histological alterations including glomerular edema and tubular necrosis. Hyalinization of tubules with deposition of proteinaceous material in the tubule lumen, tubule epithelial cell vacuoles, tubular edema and epithelial cell lysis was also observed. Leukocytic infiltration was neither observed in the glomerulus nor the tubules. Renal vessels showed no sign of inflammatory response. Additionally, biochemical analyses showed such toxin-induced changes in renal function as urine alkalinization, hematuria and azotemia with elevation of blood urea nitrogen levels. Immunofluorescence with dermonecrotic toxin antibodies and confocal microscopy analysis showed deposition and direct binding of this toxin to renal intrinsic structures. By immunoblotting with a hyperimmune dermonecrotic toxin antiserum on renal lysates from toxin-treated mice, we detected a positive signal at the region of 33-35 kDa, which strengthens the idea that renal failure is directly induced by dermonecrotic toxin. Immunofluorescence reaction with dermonecrotic toxin antibodies revealed deposition and binding of this toxin directly in MDCK epithelial cells in culture. Similarly, dermonecrotic toxin treatment caused morphological alterations of MDCK cells including cytoplasmic vacuoles, blebs, evoked impaired spreading and detached cells from each other and from

  13. Biological methods for marine toxin detection.

    PubMed

    Vilariño, Natalia; Louzao, M Carmen; Vieytes, Mercedes R; Botana, Luis M

    2010-07-01

    The presence of marine toxins in seafood poses a health risk to human consumers which has prompted the regulation of the maximum content of marine toxins in seafood in the legislations of many countries. Most marine toxin groups are detected by animal bioassays worldwide. Although this method has well known ethical and technical drawbacks, it is the official detection method for all regulated phycotoxins except domoic acid. Much effort by the scientific and regulatory communities has been focused on the development of alternative techniques that enable the substitution or reduction of bioassays; some of these have recently been included in the official detection method list. During the last two decades several biological methods including use of biosensors have been adapted for detection of marine toxins. The main advances in marine toxin detection using this kind of technique are reviewed. Biological methods offer interesting possibilities for reduction of the number of biosassays and a very promising future of new developments.

  14. Crystallization of isoelectrically homogeneous cholera toxin

    SciTech Connect

    Spangler, B.D.; Westbrook, E.M. )

    1989-02-07

    Past difficulty in growing good crystals of cholera toxin has prevented the study of the crystal structure of this important protein. The authors have determined that failure of cholera toxin to crystallize well has been due to its heterogeneity. They have now succeeded in overcoming the problem by isolating a single isoelectric variant of this oligomeric protein (one A subunit and five B subunits). Cholera toxin purified by their procedure readily forms large single crystals. The crystal form has been described previously. They have recorded data from native crystals of cholera toxin to 3.0-{angstrom} resolution with our electronic area detectors. With these data, they have found the orientation of a 5-fold symmetry axis within these crystals, perpendicular to the screw dyad of the crystal. They are now determining the crystal structure of cholera toxin by a combination of multiple heavy-atom isomorphous replacement and density modification techniques, making use of rotational 5-fold averaging of the B subunits.

  15. Cyanobacterial Alkanes Modulate Photosynthetic Cyclic Electron Flow to Assist Growth under Cold Stress

    PubMed Central

    Berla, Bertram M.; Saha, Rajib; Maranas, Costas D.; Pakrasi, Himadri B.

    2015-01-01

    All cyanobacterial membranes contain diesel-range C15-C19 hydrocarbons at concentrations similar to chlorophyll. Recently, two universal but mutually exclusive hydrocarbon production pathways in cyanobacteria were discovered. We engineered a mutant of Synechocystis sp. PCC 6803 that produces no alkanes, which grew poorly at low temperatures. We analyzed this defect by assessing the redox kinetics of PSI. The mutant exhibited enhanced cyclic electron flow (CEF), especially at low temperature. CEF raises the ATP:NADPH ratio from photosynthesis and balances reductant requirements of biosynthesis with maintaining the redox poise of the electron transport chain. We conducted in silico flux balance analysis and showed that growth rate reaches a distinct maximum for an intermediate value of CEF equivalent to recycling 1 electron in 4 from PSI to the plastoquinone pool. Based on this analysis, we conclude that the lack of membrane alkanes causes higher CEF, perhaps for maintenance of redox poise. In turn, increased CEF reduces growth by forcing the cell to use less energy-efficient pathways, lowering the quantum efficiency of photosynthesis. This study highlights the unique and universal role of medium-chain hydrocarbons in cyanobacterial thylakoid membranes: they regulate redox balance and reductant partitioning in these oxygenic photosynthetic cells under stress. PMID:26459862

  16. Ecology and spatial pattern of cyanobacterial community island patches in the Atacama Desert, Chile

    NASA Astrophysics Data System (ADS)

    Warren-Rhodes, Kimberley A.; Dungan, Jennifer L.; Piatek, Jennifer; Stubbs, Kristin; Gómez-Silva, Benito; Chen, Yong; McKay, Christopher P.

    2007-12-01

    Plant landscape ecology studies have been carried out for decades and are fundamental to biological research. In contrast, few corollary spatial landscape studies exist for microorganisms, particularly in extreme environments. To address this gap, we mapped the abundance and spatial distribution of photoautotrophs colonizing translucent rocks in several sites in the Atacama Desert, including the hyperarid core. Cyanobacterial communities at all sites are predominantly (≥75%) `perilithic' (confined to the periphery of rocks) and occur in non-random spatial patterns ("island patches") at multiple scales. Cyanobacterial patches typically contain 1-5 colonized rocks but in some cases support much higher numbers. A high resolution mapping of a single 18-m2 rock cluster at the Aguas Calientes study site (25°S, 69°W) revealed colonization of 5.2% (49 of 948 quartz rocks) and showed colonized rocks to be much larger (˜2X) than the available mean rock size. Ripley's K and point pattern analyses show that quartz rocks are not "selected" or occupied by cyanobacteria randomly, but that non-random processes distinct from those creating the background rock pattern must be invoked to explain microbial patchiness in the Atacama Desert. These processes include physical controls (rock size/orientation, microtopography) that reflect resource (water) limitations, and biological dispersal via rainfall, fog and wind.

  17. Treatment of Cyanobacterial (Microcystin) Toxicosis Using Oral Cholestyramine: Case Report of a Dog from Montana

    PubMed Central

    Rankin, Kelly A.; Alroy, Karen A.; Kudela, Raphael M.; Oates, Stori C.; Murray, Michael J.; Miller, Melissa A.

    2013-01-01

    A two and a half year old spayed female Miniature Australian Shepherd presented to a Montana veterinary clinic with acute onset of anorexia, vomiting and depression. Two days prior, the dog was exposed to an algal bloom in a community lake. Within h, the animal became lethargic and anorexic, and progressed to severe depression and vomiting. A complete blood count and serum chemistry panel suggested acute hepatitis, and a severe coagulopathy was noted clinically. Feces from the affected dog were positive for the cyanobacterial biotoxin, microcystin-LA (217 ppb). The dog was hospitalized for eight days. Supportive therapy consisted of fluids, mucosal protectants, vitamins, antibiotics, and nutritional supplements. On day five of hospitalization, a bile acid sequestrant, cholestyramine, was administered orally. Rapid clinical improvement was noted within 48 h of initiating oral cholestyramine therapy. At 17 days post-exposure the dog was clinically normal, and remained clinically normal at re-check, one year post-exposure. To our knowledge, this is the first report of successful treatment of canine cyanobacterial (microcystin) toxicosis. Untreated microcystin intoxication is commonly fatal, and can result in significant liver damage in surviving animals. The clinical success of this case suggests that oral administration of cholestyramine, in combination with supportive therapy, could significantly reduce hospitalization time, cost-of-care and mortality for microcystin-poisoned animals. PMID:23888515

  18. A cyanobacterial recombination study, involving an efficient N2-fixing non-heterocystous partner.

    PubMed

    Vaishampayan, A; Sinha, R P; Gupta, A K; Häder, D P

    2000-09-01

    Many filamentous cyanobacteria fix atmospheric nitrogen under natural conditions in specialized anaerobic compartments, heterocysts, interspersed between vegetative cells, which provide protection to the O2-sensitive nitrogenase. A few unicellular cyanobacterial strains are also known to fix nitrogen aerobically at a slower rate. Filamentous cyanobacteria lacking heterocysts are not known so far to fix nitrogen. We describe the isolation and purification of a non-heterocystous filamentous cyanobacterium from the fronds of the water-fern Azolla, fixing nitrogen at 18.7+/-0.2 n moles ethylene microg Chl. a(-1) h(-1) when grown in nitrogen-free medium at a low level of oxygen between two layers of agar. This strain of Anabaena azollae has been designated as het- nif+ (non-heterocystous and nitrogen-fixing), and is found to be easily and effectively preserved in nitrogen-free medium in standard synthetic cyanobacterial nutrient medium (pH 8.5) at a continuous light intensity of 2800 lx at 25+/-1 degrees C. This het- nif+ strain is an effective donor of the nif+ marker to a het+ nif- strain of another cyanobacterium, Nostoc muscorum, when both are grown together in a recombination study.

  19. Restriction analysis and quantitative estimation of methylated bases of filamentous and unicellular cyanobacterial DNAs.

    PubMed Central

    Padhy, R N; Hottat, F G; Coene, M M; Hoet, P P

    1988-01-01

    The DNAs of strains of three cyanobacterial genera (Anabaena, Plectonema, and Synechococcus) were found to be partially or fully resistant to many restriction endonucleases. This could be due to the absence of specific sequences or to modifications, rendering given sequences resistant to cleavage. The latter explanation is substantiated by the content of N6-methyladenine and 5-methylcytosine in these genomes, which is high in comparison with that in other bacterial genomes. dcm- and dam-like methylases are present in the three strains (based on the restriction patterns obtained with the appropriate isoschizomeric enzymes). Their contribution to the overall content of methyladenine and methylcytosine in the genomes was calculated. Partial methylation of GATC sequences was observed in Anabaena DNA. In addition, the GATC methylation patterns might not have been random in the three cyanobacterial DNA preparations, as revealed by the appearance of discrete fragments (possibly of plasmid origin) withstanding cleavage by DpnI (which requires the presence of methyladenine in the GATC sequence). Images PMID:2832390

  20. Phylogenetic analyses of cyanobacterial genomes: Quantification of horizontal gene transfer events

    PubMed Central

    Zhaxybayeva, Olga; Gogarten, J. Peter; Charlebois, Robert L.; Doolittle, W. Ford; Papke, R. Thane

    2006-01-01

    Using 1128 protein-coding gene families from 11 completely sequenced cyanobacterial genomes, we attempt to quantify horizontal gene transfer events within cyanobacteria, as well as between cyanobacteria and other phyla. A novel method of detecting and enumerating potential horizontal gene transfer events within a group of organisms based on analyses of “embedded quartets” allows us to identify phylogenetic signal consistent with a plurality of gene families, as well as to delineate cases of conflict to the plurality signal, which include horizontally transferred genes. To infer horizontal gene transfer events between cyanobacteria and other phyla, we added homologs from 168 available genomes. We screened phylogenetic trees reconstructed for each of these extended gene families for highly supported monophyly of cyanobacteria (or lack of it). Cyanobacterial genomes reveal a complex evolutionary history, which cannot be represented by a single strictly bifurcating tree for all genes or even most genes, although a single completely resolved phylogeny was recovered from the quartets’ plurality signals. We find more conflicts within cyanobacteria than between cyanobacteria and other phyla. We also find that genes from all functional categories are subject to transfer. However, in interphylum as compared to intraphylum transfers, the proportion of metabolic (operational) gene transfers increases, while the proportion of informational gene transfers decreases. PMID:16899658

  1. Interrelated modules in cyanobacterial photosynthesis: the carbon-concentrating mechanism, photorespiration, and light perception.

    PubMed

    Montgomery, Beronda L; Lechno-Yossef, Sigal; Kerfeld, Cheryl A

    2016-05-01

    Here we consider the cyanobacterial carbon-concentrating mechanism (CCM) and photorespiration in the context of the regulation of light harvesting, using a conceptual framework borrowed from engineering: modularity. Broadly speaking, biological 'modules' are semi-autonomous functional units such as protein domains, operons, metabolic pathways, and (sub)cellular compartments. They are increasingly recognized as units of both evolution and engineering. Modules may be connected by metabolites, such as NADPH, ATP, and 2PG. While the Calvin-Benson-Bassham Cycle and photorespiratory salvage pathways can be considered as metabolic modules, the carboxysome, the core of the cyanobacterial CCM, is both a structural and a metabolic module. In photosynthetic organisms, which use light cues to adapt to the external environment and which tune the photosystems to provide the ATP and reducing power for carbon fixation, light-regulated modules are critical. The primary enzyme of carbon fixation, RuBisCO, uses CO2 as a substrate, which is accumulated via the CCM. However RuBisCO also has a secondary reaction in which it utilizes O2, a by-product of the photochemical modules, which leads to photorespiration. A complete understanding of the interplay among CCM and photorespiration is predicated on uncovering their connections to the light reactions and the regulatory factors and pathways that tune these modules to external cues. We probe this connection by investigating light inputs into the CCM and photorespiratory pathways in the chromatically acclimating cyanobacterium Fremyella diplosiphon.

  2. Phosphorus removal coupled to bioenergy production by three cyanobacterial isolates in a biofilm dynamic growth system.

    PubMed

    Gismondi, Alessandra; Pippo, Francesca Di; Bruno, Laura; Antonaroli, Simonetta; Congestri, Roberta

    2016-09-01

    In the present study a closed incubator, designed for biofilm growth on artificial substrata, was used to grow three isolates of biofilm-forming heterocytous cyanobacteria using an artificial wastewater secondary effluent as the culture medium. We evaluated biofilm efficiency in removing phosphorus, by simulating biofilm-based tertiary wastewater treatment and coupled this process with biodiesel production from the developed biomass. The three strains were able to grow in the synthetic medium and remove phosphorus in percentages, between 6 and 43%, which varied between strains and also among each strain according to the biofilm growth phase. Calothrix sp. biofilm turned out to be a good candidate for tertiary treatment, showing phosphorus reducing capacity (during the exponential biofilm growth) at the regulatory level for the treated effluent water being discharged into natural water systems. Besides phosphorus removal, the three cyanobacterial biofilms produced high quality lipids, whose profile showed promising chemical stability and combustion behavior. Further integration of the proposed processes could include the integration of oil extracted from these cyanobacterial biofilms with microalgal oil known for high monounsaturated fatty acids content, in order to enhance biodiesel cold flow characteristics.

  3. Transfer of a cyanobacterial neurotoxin within a temperate aquatic ecosystem suggests pathways for human exposure.

    PubMed

    Jonasson, Sara; Eriksson, Johan; Berntzon, Lotta; Spácil, Zdenek; Ilag, Leopold L; Ronnevi, Lars-Olof; Rasmussen, Ulla; Bergman, Birgitta

    2010-05-18

    beta-methylamino-L-alanine (BMAA), a neurotoxic nonprotein amino acid produced by most cyanobacteria, has been proposed to be the causative agent of devastating neurodegenerative diseases on the island of Guam in the Pacific Ocean. Because cyanobacteria are widespread globally, we hypothesized that BMAA might occur and bioaccumulate in other ecosystems. Here we demonstrate, based on a recently developed extraction and HPLC-MS/MS method and long-term monitoring of BMAA in cyanobacterial populations of a temperate aquatic ecosystem (Baltic Sea, 2007-2008), that BMAA is biosynthesized by cyanobacterial genera dominating the massive surface blooms of this water body. BMAA also was found at higher concentrations in organisms of higher trophic levels that directly or indirectly feed on cyanobacteria, such as zooplankton and various vertebrates (fish) and invertebrates (mussels, oysters). Pelagic and benthic fish species used for human consumption were included. The highest BMAA levels were detected in the muscle and brain of bottom-dwelling fishes. The discovery of regular biosynthesis of the neurotoxin BMAA in a large temperate aquatic ecosystem combined with its possible transfer and bioaccumulation within major food webs, some ending in human consumption, is alarming and requires attention.

  4. Transfer of a cyanobacterial neurotoxin within a temperate aquatic ecosystem suggests pathways for human exposure

    PubMed Central

    Jonasson, Sara; Eriksson, Johan; Berntzon, Lotta; Spáčil, Zdenĕk; Ilag, Leopold L.; Ronnevi, Lars-Olof; Rasmussen, Ulla; Bergman, Birgitta

    2010-01-01

    β-methylamino-L-alanine (BMAA), a neurotoxic nonprotein amino acid produced by most cyanobacteria, has been proposed to be the causative agent of devastating neurodegenerative diseases on the island of Guam in the Pacific Ocean. Because cyanobacteria are widespread globally, we hypothesized that BMAA might occur and bioaccumulate in other ecosystems. Here we demonstrate, based on a recently developed extraction and HPLC-MS/MS method and long-term monitoring of BMAA in cyanobacterial populations of a temperate aquatic ecosystem (Baltic Sea, 2007–2008), that BMAA is biosynthesized by cyanobacterial genera dominating the massive surface blooms of this water body. BMAA also was found at higher concentrations in organisms of higher trophic levels that directly or indirectly feed on cyanobacteria, such as zooplankton and various vertebrates (fish) and invertebrates (mussels, oysters). Pelagic and benthic fish species used for human consumption were included. The highest BMAA levels were detected in the muscle and brain of bottom-dwelling fishes. The discovery of regular biosynthesis of the neurotoxin BMAA in a large temperate aquatic ecosystem combined with its possible transfer and bioaccumulation within major food webs, some ending in human consumption, is alarming and requires attention. PMID:20439734

  5. Improving derivatization efficiency of BMAA utilizing AccQ-Tag in a complex cyanobacterial matrix.

    PubMed

    Eriksson, Johan; Jonasson, Sara; Papaefthimiou, Dimitra; Rasmussen, Ulla; Bergman, Birgitta

    2009-01-01

    Two different assays have been developed and used in order to investigate the optimal conditions for derivatization and detection of acid beta-N-methyl-amino-L-alanine (BMAA) in a cyanobacterial sample. BMAA was extracted from cyanobacterial cultures both from the cytosolic ("free") fraction and in the precipitated ("protein") fraction using a newly developed extraction scheme and the sample matrix was standardized according to protein concentration to ensure the highest possible derivative yield. A rapid and sensitive HPLC method for fluorescence detection of the non-protein amino acid BMAA in cyanobacteria, utilizing the Waters AccQ-Tag chemistry and Chromolith Performance RP-18e columns was developed. Using this new method and utilizing a different buffer system and column than that recommended by Waters, we decreased the time between injections by 75%. The limit of quantification was determined to be 12 nmol and limit of detection as 120 fmol. The linear range was in the range of 8.5 nmol-84 pmol. Accuracy and precision were well within FDA guidelines for bioanalysis.

  6. Temperature and Cyanobacterial Bloom Biomass Influence Phosphorous Cycling in Eutrophic Lake Sediments

    PubMed Central

    Chen, Mo; Ye, Tian-Ran; Krumholz, Lee R.; Jiang, He-Long

    2014-01-01

    Cyanobacterial blooms frequently occur in freshwater lakes, subsequently, substantial amounts of decaying cyanobacterial bloom biomass (CBB) settles onto the lake sediments where anaerobic mineralization reactions prevail. Coupled Fe/S cycling processes can influence the mobilization of phosphorus (P) in sediments, with high releases often resulting in eutrophication. To better understand eutrophication in Lake Taihu (PRC), we investigated the effects of CBB and temperature on phosphorus cycling in lake sediments. Results indicated that added CBB not only enhanced sedimentary iron reduction, but also resulted in a change from net sulfur oxidation to sulfate reduction, which jointly resulted in a spike of soluble Fe(II) and the formation of FeS/FeS2. Phosphate release was also enhanced with CBB amendment along with increases in reduced sulfur. Further release of phosphate was associated with increases in incubation temperature. In addition, CBB amendment resulted in a shift in P from the Fe-adsorbed P and the relatively unreactive Residual-P pools to the more reactive Al-adsorbed P, Ca-bound P and organic-P pools. Phosphorus cycling rates increased on addition of CBB and were higher at elevated temperatures, resulting in increased phosphorus release from sediments. These findings suggest that settling of CBB into sediments will likely increase the extent of eutrophication in aquatic environments and these processes will be magnified at higher temperatures. PMID:24682039

  7. A natural view of microbial biodiversity within hot spring cyanobacterial mat communities

    NASA Technical Reports Server (NTRS)

    Ward, D. M.; Ferris, M. J.; Nold, S. C.; Bateson, M. M.

    1998-01-01

    This review summarizes a decade of research in which we have used molecular methods, in conjunction with more traditional approaches, to study hot spring cyanobacterial mats as models for understanding principles of microbial community ecology. Molecular methods reveal that the composition of these communities is grossly oversimplified by microscopic and cultivation methods. For example, none of 31 unique 16S rRNA sequences detected in the Octopus Spring mat, Yellowstone National Park, matches that of any prokaryote previously cultivated from geothermal systems; 11 are contributed by genetically diverse cyanobacteria, even though a single cyanobacterial species was suspected based on morphologic and culture analysis. By studying the basis for the incongruity between culture and molecular samplings of community composition, we are beginning to cultivate isolates whose 16S rRNA sequences are readily detected. By placing the genetic diversity detected in context with the well-defined natural environmental gradients typical of hot spring mat systems, the relationship between gene and species diversity is clarified and ecological patterns of species occurrence emerge. By combining these ecological patterns with the evolutionary patterns inherently revealed by phylogenetic analysis of gene sequence data, we find that it may be possible to understand microbial biodiversity within these systems by using principles similar to those developed by evolutionary ecologists to understand biodiversity of larger species. We hope that such an approach guides microbial ecologists to a more realistic and predictive understanding of microbial species occurrence and responsiveness in both natural and disturbed habitats.

  8. Photosynthetic action spectra and adaptation to spectral light distribution in a benthic cyanobacterial mat

    NASA Technical Reports Server (NTRS)

    Jorgensen, B. B.; Cohen, Y.; Des Marais, D. J.

    1987-01-01

    We studied adaptation to spectral light distribution in undisturbed benthic communities of cyanobacterial mats growing in hypersaline ponds at Guerrero Negro, Baja California, Mexico. Microscale measurements of oxygen photosynthesis and action spectra were performed with microelectrodes; spectral radiance was measured with fiber-optic microprobes. The spatial resolution of all measurements was 0.1 mm, and the spectral resolution was 10 to 15 nm. Light attenuation spectra showed absorption predominantly by chlorophyll a (Chl a) (430 and 670 nm), phycocyanin (620 nm), and carotenoids (440 to 500 nm). Blue light (450 nm) was attenuated 10-fold more strongly than red light (600 nm). The action spectra of the surface film of diatoms accordingly showed activity over the whole spectrum, with maxima for Chl a and carotenoids. The underlying dense Microcoleus population showed almost exclusively activity dependent upon light harvesting by phycobilins at 550 to 660 nm. Maximum activity was at 580 and 650 nm, indicating absorption by phycoerythrin and phycocyanin as well as by allophycocyanin. Very little Chl a-dependent activity could be detected in the cyanobacterial action spectrum, even with additional 600-nm light to excite photosystem II. The depth distribution of photosynthesis showed detectable activity down to a depth of 0.8 to 2.5 mm, where the downwelling radiant flux at 600 nm was reduced to 0.2 to 0.6% of the surface flux.

  9. Rapid Reactivation of Cyanobacterial Photosynthesis and Migration upon Rehydration of Desiccated Marine Microbial Mats

    PubMed Central

    Chennu, Arjun; Grinham, Alistair; Polerecky, Lubos; de Beer, Dirk; Al-Najjar, Mohammad A. A.

    2015-01-01

    Desiccated cyanobacterial mats are the dominant biological feature in the Earth’s arid zones. While the response of desiccated cyanobacteria to rehydration is well-documented for terrestrial systems, information about the response in marine systems is lacking. We used high temporal resolution hyperspectral imaging, liquid chromatography, pulse-amplitude fluorometry, oxygen microsensors, and confocal laser microscopy to study this response in a desiccated microbial mat from Exmouth Gulf, Australia. During the initial 15 min after rehydration chlorophyll a concentrations increased 2–5 fold and cyanobacterial photosynthesis was re-established. Although the mechanism behind this rapid increase of chlorophyll a remains unknown, we hypothesize that it involves resynthesis from a precursor stored in desiccated cyanobacteria. The subsequent phase (15 min–48 h) involved migration of the reactivated cyanobacteria toward the mat surface, which led, together with a gradual increase in chlorophyll a, to a further increase in photosynthesis. We conclude that the response involving an increase in chlorophyll a and recovery of photosynthetic activity within minutes after rehydration is common for cyanobacteria from desiccated mats of both terrestrial and marine origin. However, the response of upward migration and its triggering factor appear to be mat-specific and likely linked to other factors. PMID:26733996

  10. A Natural View of Microbial Biodiversity within Hot Spring Cyanobacterial Mat Communities

    PubMed Central

    Ward, David M.; Ferris, Michael J.; Nold, Stephen C.; Bateson, Mary M.

    1998-01-01

    This review summarizes a decade of research in which we have used molecular methods, in conjunction with more traditional approaches, to study hot spring cyanobacterial mats as models for understanding principles of microbial community ecology. Molecular methods reveal that the composition of these communities is grossly oversimplified by microscopic and cultivation methods. For example, none of 31 unique 16S rRNA sequences detected in the Octopus Spring mat, Yellowstone National Park, matches that of any prokaryote previously cultivated from geothermal systems; 11 are contributed by genetically diverse cyanobacteria, even though a single cyanobacterial species was suspected based on morphologic and culture analysis. By studying the basis for the incongruity between culture and molecular samplings of community composition, we are beginning to cultivate isolates whose 16S rRNA sequences are readily detected. By placing the genetic diversity detected in context with the well-defined natural environmental gradients typical of hot spring mat systems, the relationship between gene and species diversity is clarified and ecological patterns of species occurrence emerge. By combining these ecological patterns with the evolutionary patterns inherently revealed by phylogenetic analysis of gene sequence data, we find that it may be possible to understand microbial biodiversity within these systems by using principles similar to those developed by evolutionary ecologists to understand biodiversity of larger species. We hope that such an approach guides microbial ecologists to a more realistic and predictive understanding of microbial species occurrence and responsiveness in both natural and disturbed habitats. PMID:9841675

  11. Influence of alum on cyanobacterial blooms and water quality of earthen fish ponds.

    PubMed

    Dawah, Aida; Soliman, Ashraf; Abomohra, Abd El-Fatah; Battah, Mohamed; Anees, Doaa

    2015-11-01

    Eruption of blue-green algal blooms occurs frequently in eutrophic lakes and fish ponds, with associated unpleasant odor and horrid scums. In the present study, we conducted a pre-test experiment in 3 m(3) outdoor concrete ponds to determine the optimum concentration of aluminum sulfate (alum) required for reduction of the cyanobacterial blooms without negative effect on fish growth. As a consequence, 10 mg L(-1) alum was named as the optimum concentration that was applied in 1000 m(3) earthen fish ponds. Obtained results showed that Secchi disc values significantly increased from 10 to 24 cm after 14 days of alum application. Alum-treated ponds showed a reduction in total phytoplankton counts by 94 and 96% compared to the corresponding controls after 10 and 14 days, respectively. Abundance of blue-green algae in the treated ponds was decreased by 98% compared to the corresponding control after 14 days of alum application. Consequently, dissolved oxygen, pH, total phosphorus, orthophosphate, and chlorophyll "a" content declined significantly. Our study revealed that using 10 mg L(-1) of alum is an effective way to control cyanobacterial blooms in eutrophic waters, especially in fish ponds, without negative effect in water quality.

  12. Cyanobacterial distributions along a physico-chemical gradient in the Northeastern Pacific Ocean.

    PubMed

    Sudek, Sebastian; Everroad, R Craig; Gehman, Alyssa-Lois M; Smith, Jason M; Poirier, Camille L; Chavez, Francisco P; Worden, Alexandra Z

    2015-10-01

    The cyanobacteria Prochlorococcus and Synechococcus are important marine primary producers. We explored their distributions and covariance along a physico-chemical gradient from coastal to open ocean waters in the Northeastern Pacific Ocean. An inter-annual pattern was delineated in the dynamic transition zone where upwelled and eastern boundary current waters mix, and two new Synechococcus clades, Eastern Pacific Clade (EPC) 1 and EPC2, were identified. By applying state-of-the-art phylogenetic analysis tools to bar-coded 16S amplicon datasets, we observed higher abundance of Prochlorococcus high-light I (HLI) and low-light I (LLI) in years when more oligotrophic water intruded farther inshore, while under stronger upwelling Synechococcus I and IV dominated. However, contributions of some cyanobacterial clades were proportionally relatively constant, e.g. Synechococcus EPC2. In addition to supporting observations that Prochlorococcus LLI thrive at higher irradiances than other LL taxa, the results suggest LLI tolerate lower temperatures than previously reported. The phylogenetic precision of our 16S rRNA gene analytical approach and depth of bar-coded sequencing also facilitated detection of clades at low abundance in unexpected places. These include Prochlorococcus at the coast and Cyanobium-related sequences offshore, although it remains unclear whether these came from resident or potentially advected cells. Our study enhances understanding of cyanobacterial distributions in an ecologically important eastern boundary system.

  13. Ultrastructural and genetic characteristics of endolithic cyanobacterial biofilms colonizing Antarctic granite rocks.

    PubMed

    de los Ríos, Asunción; Grube, Martin; Sancho, Leopoldo G; Ascaso, Carmen

    2007-02-01

    The precise identification of the cyanobacteria that comprise an endolithic biofilm is hindered by difficulties in culturing the organisms found in these biofilms and a lack of previous molecular and ultrastructural data. This study characterizes, both at the ultrastructural and molecular level, two different cyanobacterial biofilms found in fissures of granite from continental Antarctica. Electron microscopy revealed structural differences between the two biofilms. One was only loosely adhered to the substrate, while the other biofilm showed a closer association between cells and rock minerals and was tightly attached to the substrate. Cells from both biofilms where ultrastructurally distinct, displaying, for instance, clear differences in their sheaths. The amounts of EPS and their organization associated with the cyanobacteria may determine the differences in adhesion and effects on the lithic substrate observed in the biofilms. By sequencing part of the 16S rRNA gene, the two cyanobacteria were also genetically characterized. The gene sequence of the cells comprising the biofilm that was tightly attached to the lithic substrate showed most homology with that of an endolithic cyanobacterium from Switzerland (AY153458), and the cyanobacterial type loosely adhered to the rock, clustered with Acaryochloris marina, the only organism unequivocally known to contain chlorophyll d. This study reveals the presence of at least two different types of endolithic biofilm, dominated each by a single type of cyanobacterium, able to withstand the harsh conditions of the Antarctic climate.

  14. The cyanobacterial metabolite nocuolin a is a natural oxadiazine that triggers apoptosis in human cancer cells

    PubMed Central

    Voráčová, Kateřina; Hájek, Jan; Mareš, Jan; Urajová, Petra; Kuzma, Marek; Cheel, José; Villunger, Andreas; Kapuscik, Alexandra; Bally, Marcel; Novák, Petr; Kabeláč, Martin; Krumschnabel, Gerhard; Lukeš, Martin; Voloshko, Ludmila; Kopecký, Jiří; Hrouzek, Pavel

    2017-01-01

    Oxadiazines are heterocyclic compounds containing N-N-O or N-N-C-O system within a six membered ring. These structures have been up to now exclusively prepared via organic synthesis. Here, we report the discovery of a natural oxadiazine nocuolin A (NoA) that has a unique structure based on 1,2,3-oxadiazine. We have identified this compound in three independent cyanobacterial strains of genera Nostoc, Nodularia, and Anabaena and recognized the putative gene clusters for NoA biosynthesis in their genomes. Its structure was characterized using a combination of NMR, HRMS and FTIR methods. The compound was first isolated as a positive hit during screening for apoptotic inducers in crude cyanobacterial extracts. We demonstrated that NoA-induced cell death has attributes of caspase-dependent apoptosis. Moreover, NoA exhibits a potent anti-proliferative activity (0.7–4.5 μM) against several human cancer lines, with p53-mutated cell lines being even more sensitive. Since cancers bearing p53 mutations are resistant to several conventional anti-cancer drugs, NoA may offer a new scaffold for the development of drugs that have the potential to target tumor cells independent of their p53 status. As no analogous type of compound was previously described in the nature, NoA establishes a novel class of bioactive secondary metabolites. PMID:28253280

  15. Cyanobacterial community structure as seen from RNA polymerase gene sequence analysis

    SciTech Connect

    Palenik, B.

    1994-09-01

    PCR was used to amplify DNA-dependent RNA polymerase gene sequences specifically from the cyanobacterial population in a seawater sample from the Sargasso Sea. Sequencing and analysis of the cloned fragments suggests that the population in the sample consisted of two distinct clusters of Prochlorococcus-like cyanobacteria and four clusters of Synechococcus-like cyanobacteria. The diversity within these clusters was significantly different, however. Clones within each Synechococcus-like cluster were 99 to 100% identical, while each Prochlorococcus-like cluster was only 91% identical at the nucleotide level. One Prochlorococcus-like cluster was significantly more closely related to a Mediterranean Sea (surface) Prochlorococcus isolate than to the other cluster, showing the highly divergent nature of this group even in one sample. The approach described here can be used as a general method for examining cyanobacterial diversity, while an oligotrophic ocean ecosystem such as the Sargasso Sea may be an ideal model for examining diversity in relation to environmental parameters. 51 refs., 3 figs., 2 tabs.

  16. Diversification of DnaA dependency for DNA replication in cyanobacterial evolution.

    PubMed

    Ohbayashi, Ryudo; Watanabe, Satoru; Ehira, Shigeki; Kanesaki, Yu; Chibazakura, Taku; Yoshikawa, Hirofumi

    2016-05-01

    Regulating DNA replication is essential for all living cells. The DNA replication initiation factor DnaA is highly conserved in prokaryotes and is required for accurate initiation of chromosomal replication at oriC. DnaA-independent free-living bacteria have not been identified. The dnaA gene is absent in plastids and some symbiotic bacteria, although it is not known when or how DnaA-independent mechanisms were acquired. Here, we show that the degree of dependency of DNA replication on DnaA varies among cyanobacterial species. Deletion of the dnaA gene in Synechococcus elongatus PCC 7942 shifted DNA replication from oriC to a different site as a result of the integration of an episomal plasmid. Moreover, viability during the stationary phase was higher in dnaA disruptants than in wild-type cells. Deletion of dnaA did not affect DNA replication or cell growth in Synechocystis sp. PCC 6803 or Anabaena sp. PCC 7120, indicating that functional dependency on DnaA was already lost in some nonsymbiotic cyanobacterial lineages during diversification. Therefore, we proposed that cyanobacteria acquired DnaA-independent replication mechanisms before symbiosis and such an ancestral cyanobacterium was the sole primary endosymbiont to form a plastid precursor.

  17. Diel Variation in Gene Expression of the CO2-Concentrating Mechanism during a Harmful Cyanobacterial Bloom

    PubMed Central

    Sandrini, Giovanni; Tann, Robert P.; Schuurmans, J. Merijn; van Beusekom, Sebastiaan A. M.; Matthijs, Hans C. P.; Huisman, Jef

    2016-01-01

    Dense phytoplankton blooms in eutrophic waters often experience large daily fluctuations in environmental conditions. We investigated how this diel variation affects in situ gene expression of the CO2-concentrating mechanism (CCM) and other selected genes of the harmful cyanobacterium Microcystis aeruginosa. Photosynthetic activity of the cyanobacterial bloom depleted the dissolved CO2 concentration, raised pH to 10, and caused large diel fluctuations in the bicarbonate and O2 concentration. The Microcystis population consisted of three Ci uptake genotypes that differed in the presence of the low-affinity and high-affinity bicarbonate uptake genes bicA and sbtA. Expression of the bicarbonate uptake genes bicA, sbtA, and cmpA (encoding a subunit of the high-affinity bicarbonate uptake system BCT1), the CCM transcriptional regulator gene ccmR and the photoprotection gene flv4 increased at first daylight and was negatively correlated with the bicarbonate concentration. In contrast, genes of the two CO2 uptake systems were constitutively expressed, whereas expression of the RuBisCO chaperone gene rbcX, the carboxysome gene ccmM, and the photoprotection gene isiA was highest at night and down-regulated during daytime. In total, our results show that the harmful cyanobacterium Microcystis is very responsive to the large diel variations in carbon and light availability often encountered in dense cyanobacterial blooms. PMID:27148233

  18. Prevalence of Ca2+-ATPase-Mediated Carbonate Dissolution among Cyanobacterial Euendoliths

    PubMed Central

    Ramírez-Reinat, E. L.

    2012-01-01

    Recent physiological work has shown that the filamentous euendolithic cyanobacterium Mastigocoleus testarum (strain BC008) is able to bore into solid carbonates using Ca2+-ATPases to take up Ca2+ from the medium at the excavation front, promoting dissolution of CaCO3 there. It is not known, however, if this is a widespread mechanism or, rather, a unique capability of this model strain. To test this, we undertook a survey of multispecies euendolithic microbial assemblages infesting natural carbonate substrates in marine coastal waters of the Caribbean, Mediterranean, South Pacific, and Sea of Cortez. Microscopic examination revealed the presence of complex assemblages of euendoliths, encompassing 3 out of the 5 major cyanobacterial orders. 16S rRNA gene clone libraries detected even greater diversity, particularly among the thin-filamentous forms, and allowed us to categorize the endoliths in our samples into 8 distinct phylogenetic clades. Using real-time Ca2+ imaging under a confocal laser scanning microscope, we could show that all communities displayed light-dependent formation of Ca2+-supersaturated zones in and around boreholes, a staple of actively boring phototrophs. In 3 out of 4 samples, boring activity was sensitive to at least one of two inhibitors of Ca2+-ATPase transporters (thapsigargin or tert-butylhydroquinone), indicating that the Ca2+-ATPase mechanism is widespread among cyanobacterial euendoliths but perhaps not universal. Function-community structure correlations point to one particular clade of baeocyte-forming euendoliths as the potential exception. PMID:22038600

  19. The cyanobacterial metabolite nocuolin a is a natural oxadiazine that triggers apoptosis in human cancer cells.

    PubMed

    Voráčová, Kateřina; Hájek, Jan; Mareš, Jan; Urajová, Petra; Kuzma, Marek; Cheel, José; Villunger, Andreas; Kapuscik, Alexandra; Bally, Marcel; Novák, Petr; Kabeláč, Martin; Krumschnabel, Gerhard; Lukeš, Martin; Voloshko, Ludmila; Kopecký, Jiří; Hrouzek, Pavel

    2017-01-01

    Oxadiazines are heterocyclic compounds containing N-N-O or N-N-C-O system within a six membered ring. These structures have been up to now exclusively prepared via organic synthesis. Here, we report the discovery of a natural oxadiazine nocuolin A (NoA) that has a unique structure based on 1,2,3-oxadiazine. We have identified this compound in three independent cyanobacterial strains of genera Nostoc, Nodularia, and Anabaena and recognized the putative gene clusters for NoA biosynthesis in their genomes. Its structure was characterized using a combination of NMR, HRMS and FTIR methods. The compound was first isolated as a positive hit during screening for apoptotic inducers in crude cyanobacterial extracts. We demonstrated that NoA-induced cell death has attributes of caspase-dependent apoptosis. Moreover, NoA exhibits a potent anti-proliferative activity (0.7-4.5 μM) against several human cancer lines, with p53-mutated cell lines being even more sensitive. Since cancers bearing p53 mutations are resistant to several conventional anti-cancer drugs, NoA may offer a new scaffold for the development of drugs that have the potential to target tumor cells independent of their p53 status. As no analogous type of compound was previously described in the nature, NoA establishes a novel class of bioactive secondary metabolites.

  20. Variability in the sxt Gene Clusters of PSP Toxin Producing Aphanizomenon gracile Strains from Norway, Spain, Germany and North America

    PubMed Central

    Cerasino, Leonardo; Hostyeva, Vladyslava; Cirés, Samuel

    2016-01-01

    Paralytic shellfish poisoning (PSP) toxin production has been detected worldwide in the cyanobacterial genera Anabaena, Lyngbya, Scytonema, Cuspidothrix and Aphanizomenon. In Europe Aphanizomenon gracile and Cuspidothrix issatschenkoi are the only known producers of PSP toxins and are found in Southwest and Central European freshwater bodies. In this study the PSP toxin producing Aphanizomenon sp. strain NIVA-CYA 851 was isolated from the Norwegian Lake Hillestadvannet. In a polyphasic approach NIVA-CYA 851 was morphologically and phylogenetically classified, and investigated for toxin production. The strain NIVA-CYA 851 was identified as A. gracile using 16S rRNA gene phylogeny and was confirmed to produce neosaxitoxin, saxitoxin and gonyautoxin 5 by LC-MS. The whole sxt gene clusters (circa 27.3 kb) of four A. gracile strains: NIVA-CYA 851 (Norway); NIVA-CYA 655 & NIVA-CYA 676 (Germany); and UAM 529 (Spain), all from latitudes between 40° and 59° North were sequenced and compared with the sxt gene cluster of reference strain A. gracile NH-5 from the USA. All five sxt gene clusters are highly conserved with similarities exceeding 99.4%, but they differ slightly in the number and presence of single nucleotide polymorphisms (SNPs) and insertions/deletions (In/Dels). Altogether 178 variable sites (44 SNPs and 4 In/Dels, comprising 134 nucleotides) were found in the sxt gene clusters of the Norwegian, German and Spanish strains compared to the reference strain. Thirty-nine SNPs were located in 16 of the 27 coding regions. The sxt gene clusters of NIVA-CYA 851, NIVA-CYA 655, NIVA-CYA 676 and UAM 529, were characterized by 15, 16, 19 and 23 SNPs respectively. Only the Norwegian strain NIVA-CYA 851 possessed an insertion of 126 base pairs (bp) in the noncoding area between the sxtA and sxtE genes and a deletion of 6 nucleotides in the sxtN gene. The sxtI gene showed the highest variability and is recommended as the best genetic marker for further phylogenetic studies

  1. Variability in the sxt Gene Clusters of PSP Toxin Producing Aphanizomenon gracile Strains from Norway, Spain, Germany and North America.

    PubMed

    Ballot, Andreas; Cerasino, Leonardo; Hostyeva, Vladyslava; Cirés, Samuel

    2016-01-01

    Paralytic shellfish poisoning (PSP) toxin production has been detected worldwide in the cyanobacterial genera Anabaena, Lyngbya, Scytonema, Cuspidothrix and Aphanizomenon. In Europe Aphanizomenon gracile and Cuspidothrix issatschenkoi are the only known producers of PSP toxins and are found in Southwest and Central European freshwater bodies. In this study the PSP toxin producing Aphanizomenon sp. strain NIVA-CYA 851 was isolated from the Norwegian Lake Hillestadvannet. In a polyphasic approach NIVA-CYA 851 was morphologically and phylogenetically classified, and investigated for toxin production. The strain NIVA-CYA 851 was identified as A. gracile using 16S rRNA gene phylogeny and was confirmed to produce neosaxitoxin, saxitoxin and gonyautoxin 5 by LC-MS. The whole sxt gene clusters (circa 27.3 kb) of four A. gracile strains: NIVA-CYA 851 (Norway); NIVA-CYA 655 & NIVA-CYA 676 (Germany); and UAM 529 (Spain), all from latitudes between 40° and 59° North were sequenced and compared with the sxt gene cluster of reference strain A. gracile NH-5 from the USA. All five sxt gene clusters are highly conserved with similarities exceeding 99.4%, but they differ slightly in the number and presence of single nucleotide polymorphisms (SNPs) and insertions/deletions (In/Dels). Altogether 178 variable sites (44 SNPs and 4 In/Dels, comprising 134 nucleotides) were found in the sxt gene clusters of the Norwegian, German and Spanish strains compared to the reference strain. Thirty-nine SNPs were located in 16 of the 27 coding regions. The sxt gene clusters of NIVA-CYA 851, NIVA-CYA 655, NIVA-CYA 676 and UAM 529, were characterized by 15, 16, 19 and 23 SNPs respectively. Only the Norwegian strain NIVA-CYA 851 possessed an insertion of 126 base pairs (bp) in the noncoding area between the sxtA and sxtE genes and a deletion of 6 nucleotides in the sxtN gene. The sxtI gene showed the highest variability and is recommended as the best genetic marker for further phylogenetic studies

  2. Cyanobacterial crusts linked to soil productivity under different grazing management practices in Northern Australia

    NASA Astrophysics Data System (ADS)

    Alchin, Bruce; Williams, Wendy

    2015-04-01

    In arid and semi-arid Australia, the central role of healthy soil ecosystems in broad-acre grazing lands may be attributed to the widespread presence of cyanobacterial crusts. In terms of soil nutrient cycling and stability their role is particularly crucial in a climate dominated by annual dry seasons and variable wet seasons. In this study, we aimed to measure the contribution of cyanobacteria to soil nutrient cycling under contrasting levels of disturbance associated with grazing management. Field sampling was carried out on six paired sites (twelve properties) located across an east-west 3,000 km transect that covered different rangeland types on grazing properties in northern Australia (Queensland, Northern Territory and Western Australia). At each location paired sites were established and two different management systems were assessed, cell-paddock rotations (25-400 ha) and continuous grazing (200-2,000 ha). Cyanobacterial soil crusts were recorded from all of the twelve sites and cyanobacteria with the capacity to fix nitrogen were found at ten of the twelve sites. The overall diversity of cyanobacteria varied from three to ten species under any type of grazing system. As field work was conducted in the dry season, it is likely that the diversity may be greater in the wet season than the initial data may indicate. The average cyanobacterial soil crust cover across soil surfaces, between grass tussocks, during the dry season was estimated to be 50.9% and, 42.6% in the early wet season. This reflected longer established crust cover (dry season) versus newly established crusts. There was a high level of variability in the biomass of cyanobacteria however; the grazing system did not have any marked effect on the biomass for any one rangeland type. The grazing system differences did not appear to significantly influence the diversity at any location except on a floodplain in the Pilbara (WA). Biological nitrogen fixation by cyanobacteria was recorded at all

  3. Toxins

    MedlinePlus

    ... trace metals and others. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine . 25th ed. Philadelphia, PA: ... Ford MD. Acute poisoning. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine . 25th ed. Philadelphia, PA: ...

  4. Effects of cyanobacterial lipopolysaccharides from microcystis on glutathione-based detoxification pathways in the zebrafish (Danio rerio) embryo.

    PubMed

    Jaja-Chimedza, Asha; Gantar, Miroslav; Mayer, Gregory D; Gibbs, Patrick D L; Berry, John P

    2012-06-01

    Cyanobacteria ("blue-green algae") are recognized producers of a diverse array of toxic secondary metabolites. Of these, the lipopolysaccharides (LPS), produced by all cyanobacteria, remain to be well investigated. In the current study, we specifically employed the zebrafish (Danio rerio) embryo to investigate the effects of LPS from geographically diverse strains of the widespread cyanobacterial genus, Microcystis, on several detoxifying enzymes/pathways, including glutathione-S-transferase (GST), glutathione peroxidase (GPx)/glutathione reductase (GR), superoxide dismutase (SOD), and catalase (CAT), and compared observed effects to those of heterotrophic bacterial (i.e., E. coli) LPS. In agreement with previous studies, cyanobacterial LPS significantly reduced GST in embryos exposed to LPS in all treatments. In contrast, GPx moderately increased in embryos exposed to LPS, with no effect on reciprocal GR activity. Interestingly, total glutathione levels were elevated in embryos exposed to Microcystis LPS, but the relative levels of reduced and oxidized glutathione (i.e., GSH/GSSG) were, likewise, elevated suggesting that oxidative stress is not involved in the observed effects as typical of heterotrophic bacterial LPS in mammalian systems. In further support of this, no effect was observed with respect to CAT or SOD activity. These findings demonstrate that Microcystis LPS affects glutathione-based detoxification pathways in the zebrafish embryo, and more generally, that this model is well suited for investigating the apparent toxicophore of cyanobacterial LPS, including possible differences in structure-activity relationships between heterotrophic and cyanobacterial LPS, and teleost fish versus mammalian systems.

  5. USE OF PHOSPHOLIPID FATTY ACID PROFILES TO STUDY THE MICROBIAL COMPOSITION OF CYANOBACTERIAL MATS IN CABO ROJO SOLAR SALTERNS

    EPA Science Inventory

    The Cabo Rojo Saltern located in the West side of Puerto Rico is a hypersaline ecosystem that consists of crystallizer ponds surrounded by series of cyanobacterial mats. Although this ecosystem harbors a variety of microorganisms not much is known about their identity and relati...

  6. UV-induced photochemical heterogeneity of dissolved and attached organic matter associated with cyanobacterial blooms in a eutrophic freshwater lake.

    PubMed

    Xu, Huacheng; Jiang, Helong

    2013-11-01

    Cyanobacterial blooms represent a significant ecological and human health problem worldwide. In aquatic environments, cyanobacterial blooms are actually surrounded by dissolved organic matter (DOM) and attached organic matter (AOM) that bind with algal cells. In this study, DOM and AOM fractionated from blooming cyanobacteria in a eutrophic freshwater lake (Lake Taihu, China) were irradiated with a polychromatic UV lamp, and the photochemical heterogeneity was investigated using fluorescence excitation-emission matrix (EEM)-parallel factor (PARAFAC) analysis and synchronous fluorescence (SF)-two dimensional correlation spectroscopy (2DCOS). It was shown that a 6-day UV irradiation caused more pronounced mineralization for DOM than AOM (59.7% vs. 41.9%). The EEM-PARAFAC analysis identified one tyrosine-, one humic-, and two tryptophan-like components in both DOM and AOM, and high component photodegradation rates were observed for DOM versus AOM (k > 0.554 vs. <0.519). Moreover, SF-2DCOS found that the photodegradation of organic matters followed the sequence of tyrosine-like > humic-like > tryptophan-like substances. Humic-like substances promoted the indirect photochemical reactions, and were responsible for the higher photochemical rate for DOM. The lower photodegradation of AOM benefited the integrality of cells in cyanobacterial blooms against the negative impact of UV irradiation. Therefore, the photochemical behavior of organic matter was related to the adaptation of enhanced-duration cyanobacterial blooms in aquatic environments.

  7. Practices that Prevent the Formation of Cyanobacterial Blooms in Water Resources and remove Cyanotoxins during Physical Treatment of Drinking Water

    EPA Science Inventory

    This book chapter presents findings of different studies on the prevention and elimination of cyanobacterial blooms in raw water resources as well as the removal of cyanotoxins during water treatment with physical processes. Initially,treatments that can be applied at the source ...

  8. Fine gravel controls hydrologic and erodibility responses to trampling disturbance for coarse-textured soils with weak cyanobacterial crusts.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We compared short-term effects of lug-soled boot trampling disturbance on water infiltration and soil erodibility on coarse-textured soils covered by a mixture of fine gravel and coarse sand over weak cyanobacterially-dominated biological soil crusts. Trampling significantly reduced final infiltrati...

  9. Correlations between cyanobacterial density and bacterial transformation to the viable but nonculturable (VBNC) state in four freshwater water bodies.

    PubMed

    Chen, Huirong; Shen, Ju; Pan, Gaoshan; Liu, Jing; Li, Jiancheng; Hu, Zhangli

    2015-10-01

    Nutrient concentrations, phytoplankton density and community composition, and the viable but nonculturable (VBNC) state of heterotrophic bacteria were investigated in three connected reservoirs and a small isolated lake in South China to study the relationship between biotic and abiotic factors and the VBNC state in bacteria. Nutrient concentrations in the reservoirs increased in the direction of water flow, whereas Wenshan Lake was more eutrophic. Cyanobacterial blooms occurred in all four water bodies, with differing seasonal trends and dominant species. In Xili and Tiegang Reservoirs, the VBNC ratio (percent of VBNC state bacteria over total viable bacteria) was high for most of the year and negatively correlated with cyanobacterial density. Laboratory co-culture experiments were performed with four heterotrophic bacterial species isolated from Wenshan Lake (Escherichia coli, Klebsiella peneumoniae, Bacillus megaterium and Bacillus cereus) and the dominant cyanobacterial species (Microcystis aeruginosa). For the first three bacterial species, the presence of M. aeruginosa induced the VBNC state and the VBNC ratio was positively correlated with M. aeruginosa density. However, B. cereus inhibited M. aeruginosa growth. These results demonstrate that cyanobacteria could potentially regulate the transformation to the VBNC state of waterborne bacteria, and suggest a role for bacteria in cyanobacterial bloom initiation and termination.

  10. Nutrient reduction magnifies the impact of extreme weather on cyanobacterial bloom formation in large shallow Lake Taihu (China).

    PubMed

    Yang, Zhen; Zhang, Min; Shi, Xiaoli; Kong, Fanxiang; Ma, Ronghua; Yu, Yang

    2016-10-15

    Cyanobacterial bloom formation is dependent on nutrient levels and meteorological conditions. In this study, we elucidated the effects of extreme weather events (EWEs, heavy rainfall and strong winds) on the cyanobacterial blooms in Lake Taihu in recent years based on an analysis of the meteorological, nutrient, and bloom area data from 2007 to 2015. The levels of total phosphorus (TP) and total nitrogen (TN) decreased by 42.5% and 31.2%, respectively, in the water of Lake Taihu over the past nine years. However, the frequency and intensity of cyanobacterial blooms did not significantly decrease. A total of 50.5% of the extended blooms (>300 km(2)) were associated with EWEs from 2007 to 2015, 36.2% of which were due to heavy rainfall and 38.3% of which were due to strong winds (25.5% were due to both). Interestingly, the frequency of the EWE-induced extended blooms significantly increased after 2012. Principal component analysis (PCA) showed that this frequency correlated positively with EWE-induced nutrient increases in the water, indicating that the complement from nutrient increases induced by EWE allow cyanobacterial cells to reach high biomass under relatively low nutrient condition. Our results suggest that EWEs play a more important role in extended bloom formation after the nutrient levels in shallow lakes are reduced.

  11. Modulation of biochemical indices in common carp (Cyprinus carpio L.) under the influence of toxic cyanobacterial biomass in diet.

    PubMed

    Kopp, Radovan; Palíková, Miroslava; Navrátil, Stanislav; Mareš, Jan

    2014-12-01

    Cyanobacteria are producers of potent and environmentally abundant microcystins, representing an emerging global health issue. In the present study, we investigated the impact of cyanobacterial biomass on biochemical indices of common carp (Cyprinus carpio L., average weight of 246 ± 73 g) under laboratory conditions. The fish were fed a diet containing cyanobacterial biomass with microcystins in high concentration (0.4 mg/kg of fish weight and day) for 28 days. Statistical evaluation of the influence of the cyanobacterial biomass in food on the biochemical indices of the juvenile carp showed only minor differences. The activity of aspartate aminotransferase value and the urea concentration were significantly reduced compared to control group. The biochemical parameters of fish blood plasma significantly rose during the experiment in the control group as well as in the experimental group. This state was probably influenced by the environmental conditions and the fish diet. A significant rising value was established in calcium creatinine, total protein, phosphorus, lactate, urea and natrium. The present study demonstrates that the oral exposure of toxic cyanobacterial biomass has a minor influence on the biochemical indices of common carp and that the effect of other factors, e.g., nutrition is more visible.

  12. Predicting cyanobacterial abundance, microcystin, and geosmin in a eutrophic drinking-water reservoir using a 14-year dataset

    USGS Publications Warehouse

    Harris, Ted D.; Graham, Jennifer

    2017-01-01

    Cyanobacterial blooms degrade water quality in drinking water supply reservoirs by producing toxic and taste-and-odor causing secondary metabolites, which ultimately cause public health concerns and lead to increased treatment costs for water utilities. There have been numerous attempts to create models that predict cyanobacteria and their secondary metabolites, most using linear models; however, linear models are limited by assumptions about the data and have had limited success as predictive tools. Thus, lake and reservoir managers need improved modeling techniques that can accurately predict large bloom events that have the highest impact on recreational activities and drinking-water treatment processes. In this study, we compared 12 unique linear and nonlinear regression modeling techniques to predict cyanobacterial abundance and the cyanobacterial secondary metabolites microcystin and geosmin using 14 years of physiochemical water quality data collected from Cheney Reservoir, Kansas. Support vector machine (SVM), random forest (RF), boosted tree (BT), and Cubist modeling techniques were the most predictive of the compared modeling approaches. SVM, RF, and BT modeling techniques were able to successfully predict cyanobacterial abundance, microcystin, and geosmin concentrations <60,000 cells/mL, 2.5 µg/L, and 20 ng/L, respectively. Only Cubist modeling predicted maxima concentrations of cyanobacteria and geosmin; no modeling technique was able to predict maxima microcystin concentrations. Because maxima concentrations are a primary concern for lake and reservoir managers, Cubist modeling may help predict the largest and most noxious concentrations of cyanobacteria and their secondary metabolites.

  13. Roles of Anthrax Toxin Receptor 2 in Anthrax Toxin Membrane Insertion and Pore Formation.

    PubMed

    Sun, Jianjun; Jacquez, Pedro

    2016-01-22

    Interaction between bacterial toxins and cellular surface receptors is an important component of the host-pathogen interaction. Anthrax toxin protective antigen (PA) binds to the cell surface receptor, enters the cell through receptor-mediated endocytosis, and forms a pore on the endosomal membrane that translocates toxin enzymes into the cytosol of the host cell. As the major receptor for anthrax toxin in vivo, anthrax toxin receptor 2 (ANTXR2) plays an essential role in anthrax toxin action by providing the toxin with a high-affinity binding anchor on the cell membrane and a path of entry into the host cell. ANTXR2 also acts as a molecular clamp by shifting the pH threshold of PA pore formation to a more acidic pH range, which prevents premature pore formation at neutral pH before the toxin reaches the designated intracellular location. Most recent studies have suggested that the disulfide bond in the immunoglobulin (Ig)-like domain of ANTXR2 plays an essential role in anthrax toxin action. Here we will review the roles of ANTXR2 in anthrax toxin action, with an emphasis on newly updated knowledge.

  14. Activation of syndecan-1 ectodomain shedding by Staphylococcus aureus alpha-toxin and beta-toxin.

    PubMed

    Park, Pyong Woo; Foster, Timothy J; Nishi, Eiichiro; Duncan, Sheila J; Klagsbrun, Michael; Chen, Ye

    2004-01-02

    Exploitation of host components by microbes to promote their survival in the hostile host environment has been a recurring theme in recent years. Available data indicate that bacterial pathogens activate ectodomain shedding of host cell surface molecules to enhance their virulence. We reported previously that several major bacterial pathogens activate ectodomain shedding of syndecan-1, the major heparan sulfate proteoglycan of epithelial cells. Here we define the molecular basis of how Staphylococcus aureus activates syndecan-1 shedding. We screened mutant S. aureus strains devoid of various toxin and protease genes and found that only strains lacking both alpha-toxin and beta-toxin genes do not stimulate shedding. Mutations in the agr global regulatory locus, which positively regulates expression of alpha- and beta-toxins and other exoproteins, also abrogated the capacity to stimulate syndecan-1 shedding. Furthermore, purified S. aureus alpha- and beta-toxins, but not enterotoxin A and toxic shock syndrome toxin-1, rapidly potentiated shedding in a concentration-dependent manner. These results establish that S. aureus activates syndecan-1 ectodomain shedding via its two virulence factors, alpha- and beta-toxins. Toxin-activated shedding was also selectively inhibited by antagonists of the host cell shedding mechanism, indicating that alpha- and beta-toxins shed syndecan-1 ectodomains through stimulation of the host cell's shedding machinery. Interestingly, beta-toxin, but not alpha-toxin, also enhanced ectodomain shedding of syndecan-4 and heparin-binding epidermal growth factor. Because shedding of these ectodomains has been implicated in promoting bacterial pathogenesis, activation of ectodomain shedding by alpha-toxin and beta-toxin may be a previously unknown virulence mechanism of S. aureus.

  15. Fungi and fungal toxins as weapons.

    PubMed

    Paterson, R Russell M

    2006-09-01

    Recent aggressive attacks on innocent citizens have resulted in governments increasing security. However, there is a good case for prevention rather than reaction. Bioweapons, mycotoxins, fungal biocontrol agents (FBCA), and even pharmaceuticals contain, or are, toxins and need to be considered in the context of the new paradigm. Is it desirable to discuss such issues? None of the fungi are (a) as toxic as botulinum toxin from Clostridium botulinum, and (b) as dangerous as nuclear weapons. One toxin may be defined as a pharmaceutical and vice versa simply by a small change in concentration or a moiety. Mycotoxins are defined as naturally occurring toxic compounds obtained from fungi. They are the biggest chronic health risk when incorporated into the diet. The current list of fungal toxins as biochemical weapons is small, although awareness is growing of the threats they may pose. T-2 toxin is perhaps the biggest concern. A clear distinction is required between the biological (fungus) and chemical (toxin) aspects of the issue. There is an obvious requirement to be able to trace these fungi and compounds in the environment and to know when concentrations are abnormal. Many FBCA, produce toxins. This paper indicates how to treat mycotoxicosis and decontaminate mycotoxins. There is considerable confusion and inconsistency surrounding this topic which requires assessment in an impartial and scientific manner.

  16. Clostridium difficile: its disease and toxins.

    PubMed Central

    Lyerly, D M; Krivan, H C; Wilkins, T D

    1988-01-01

    Clostridium difficile is the etiologic agent of pseudomembranous colitis, a severe, sometimes fatal disease that occurs in adults undergoing antimicrobial therapy. The disease, ironically, has been most effectively treated with antibiotics, although some of the newer methods of treatment such as the replacement of the bowel flora may prove more beneficial for patients who continue to relapse with pseudomembranous colitis. The organism produces two potent exotoxins designated toxin A and toxin B. Toxin A is an enterotoxin believed to be responsible for the diarrhea and mucosal tissue damage which occur during the disease. Toxin B is an extremely potent cytotoxin, but its role in the disease has not been as well studied. There appears to be a cascade of events which result in the expression of the activity of these toxins, and these events, ranging from the recognition of a trisaccharide receptor by toxin A to the synergistic action of the toxins and their possible dissemination in the body, are discussed in this review. The advantages and disadvantages of the various assays, including tissue culture assay, enzyme immunoassay, and latex agglutination, currently used in the clinical diagnosis of the disease also are discussed. PMID:3144429

  17. Single toxin dose-response models revisited

    PubMed Central

    Glaholt, SP; Kyker-Snowman, E; Shaw, JR; Chen, CY

    2016-01-01

    The goal of this paper is to offer a rigorous analysis of the sigmoid shape single toxin dose-response relationship. The toxin efficacy function is introduced and four special points, including maximum toxin efficacy and inflection points, on the dose-response curve are defined. The special points define three phases of the toxin effect on mortality: (1) toxin concentrations smaller than the first inflection point or (2) larger then the second inflection point imply low mortality rate, and (3) concentrations between the first and the second inflection points imply high mortality rate. Probabilistic interpretation and mathematical analysis for each of four models, Hill, logit, probit, and Weibull is provided. Two general model extensions are introduced: (1) the multi-target hit model that accounts for the existence of several vital receptors affected by the toxin, and (2) model with a nonzero mortality at zero concentration to account for natural mortality. Special attention is given to statistical estimation in the framework of the generalized linear model with the binomial dependent variable as the mortality count in each experiment, contrary to the widespread nonlinear regression treating the mortality rate as continuous variable. The models are illustrated using standard EPA Daphnia acute (48 hours) toxicity tests with mortality as a function of NiCl or CuSO4 toxin. PMID:27847315

  18. Mechanism of Shiga Toxin Clustering on Membranes.

    PubMed

    Pezeshkian, Weria; Gao, Haifei; Arumugam, Senthil; Becken, Ulrike; Bassereau, Patricia; Florent, Jean-Claude; Ipsen, John Hjort; Johannes, Ludger; Shillcock, Julian C

    2017-01-24

    The bacterial Shiga toxin interacts with its cellular receptor, the glycosphingolipid globotriaosylceramide (Gb3 or CD77), as a first step to entering target cells. Previous studies have shown that toxin molecules cluster on the plasma membrane, despite the apparent lack of direct interactions between them. The precise mechanism by which this clustering occurs remains poorly defined. Here, we used vesicle and cell systems and computer simulations to show that line tension due to curvature, height, or compositional mismatch, and lipid or solvent depletion cannot drive the clustering of Shiga toxin molecules. By contrast, in coarse-grained computer simulations, a correlation was found between clustering and toxin nanoparticle-driven suppression of membrane fluctuations, and experimentally we observed that clustering required the toxin molecules to be tightly bound to the membrane surface. The most likely interpretation of these findings is that a membrane fluctuation-induced force generates an effective attraction between toxin molecules. Such force would be of similar strength to the electrostatic force at separations around 1 nm, remain strong at distances up to the size of toxin molecules (several nanometers), and persist even beyond. This force is predicted to operate between manufactured nanoparticles providing they are sufficiently rigid and tightly bound to the plasma membrane, thereby suggesting a route for the targeting of nanoparticles to cells for biomedical applications.

  19. Mechanism of Shiga Toxin Clustering on Membranes

    PubMed Central

    2016-01-01

    The bacterial Shiga toxin interacts with its cellular receptor, the glycosphingolipid globotriaosylceramide (Gb3 or CD77), as a first step to entering target cells. Previous studies have shown that toxin molecules cluster on the plasma membrane, despite the apparent lack of direct interactions between them. The precise mechanism by which this clustering occurs remains poorly defined. Here, we used vesicle and cell systems and computer simulations to show that line tension due to curvature, height, or compositional mismatch, and lipid or solvent depletion cannot drive the clustering of Shiga toxin molecules. By contrast, in coarse-grained computer simulations, a correlation was found between clustering and toxin nanoparticle-driven suppression of membrane fluctuations, and experimentally we observed that clustering required the toxin molecules to be tightly bound to the membrane surface. The most likely interpretation of these findings is that a membrane fluctuation-induced force generates an effective attraction between toxin molecules. Such force would be of similar strength to the electrostatic force at separations around 1 nm, remain strong at distances up to the size of toxin molecules (several nanometers), and persist even beyond. This force is predicted to operate between manufactured nanoparticles providing they are sufficiently rigid and tightly bound to the plasma membrane, thereby suggesting a route for the targeting of nanoparticles to cells for biomedical applications. PMID:27943675

  20. Botulinum toxin for the treatment of bruxism.

    PubMed

    Tinastepe, Neslihan; Küçük, Burcu Bal; Oral, Koray

    2014-08-14

    Aims: Botulinum toxin, the most potent biological toxin, has been shown to be effective for a variety of disorders in several medical conditions, when used both therapeutically and cosmetically. In recent years, there has been a rising trend in the use of this pharmacological agent to control bruxing activity, despite its reported adverse effects. The aim of this review was to provide a brief overview to clarify the underlying essential ideas for the use of botulinum toxin in bruxism based on available scientific papers. Methodology: An electronic literature search was performed to identify publications related to botulinum toxin and its use for bruxism in PubMed. Hand searching of relevant articles was also made to identify additional studies. Results: Of the eleven identified studies, only two were randomized controlled trials, compared with the effectiveness of botulinum toxins on the reduction in the frequency of bruxism events and myofascial pain after injection. The authors of these studies concluded that botulinum toxin could be used as an effective treatment for reducing nocturnal bruxism and myofascial pain in patients with bruxism. Conclusion: Evidence-based research was limited on this topic. More randomized controlled studies are needed to confirm that botulinum toxin is safe and reliable for routine clinical use in bruxism.

  1. Isolation and characterization of a variety of microcystins from seven strains of the cyanobacterial genus Anabaena.

    PubMed Central

    Sivonen, K; Namikoshi, M; Evans, W R; Carmichael, W W; Sun, F; Rouhiainen, L; Luukkainen, R; Rinehart, K L

    1992-01-01

    Hepatotoxins (microcystins) from seven freshwater Anabaena strains originating from three different Finnish lakes and one lake in Norway were isolated by high-performance liquid chromatography and characterized by amino acid analysis and fast atom bombardment mass spectrometry. All strains produced three to seven different microcystins. A total of 17 different compounds were isolated, of which 8 were known microcystins. The known compounds identified from six strains were MCYST (microcystin)-LR, [D-Asp3]MCYST-LR, [Dha7]MCYST-LR, [D-Asp3,Dha7]MCYST-LR, MCYST-RR, [D-Asp3]MCYST-RR, [Dha7]MCYST-RR, and [D-Asp3,Dha7]MCYST-RR. With the exception of MCYST-LR and [D-Asp3]MCYST-LR, this is the first time that isolation of these toxins from Anabaena strains has been reported. Three of the strains produced one to three toxins as minor components which could not be identified. Anabaena sp. strain 66 produced four unidentified toxins. The other Anabaena strains always contained both MCYST-LR and MCYST-RR and/or their demethyl variants. Quantitative differences between toxins within and between strains were detected; at times MCYST-LR and at other times MCYST-RR or demethyl derivatives thereof were the most abundant toxins found in a strain. PMID:1514796

  2. Polypeptide toxins from animal venoms.

    PubMed

    Kozlov, Sergey A

    2007-01-01

    In the course of evolution, venomous animals developed highly specialized venomous systems that provided for drastic increase in hunting and defense efficiency. Venoms of a vast number of animal species represent complex mixtures of compounds such as ions, biogenic amines, polyamines, polypeptide neurotoxins, cytolytic peptides, enzymes, etc. that exert different functions. Natural toxins are sequentially variable molecules that are very stable structurally and produce pronounced biological effects on molecular targets. High activity made them very attractive in terms of novel structure discovery and characterization. In the present review we draw attention to the structure of polypeptide molecules preferably in the 2-12 kDa molecular mass range produced by various venomous animals that were published in patent literature. The structures were reviewed on the basis of functional relation to molecular targets. We also compared the sequence information from patents with Uniprot and other protein databanks to define structures that were patented but missing from the public databases.

  3. Association of a new type of gliding, filamentous, purple phototrophic bacterium inside bundles of Microcoleus chthonoplastes in hypersaline cyanobacterial mats

    NASA Technical Reports Server (NTRS)

    D'Amelio, E. D.; Cohen, Y.; Des Marais, D. J.

    1987-01-01

    An unidentified filamentous purple bacterium, probably belonging to a new genus or even a new family, is found in close association with the filamentous, mat-forming cyanobacterium Microcoleus chthonoplastes in a hypersaline pond at Guerrero Negro, Baja California Sur, Mexico, and in Solar Lake, Sinai, Egypt. This organism is a gliding, segmented trichome, 0.8-0.9 micrometer wide. It contains intracytoplasmic stacked lamellae which are perpendicular and obliquely oriented to the cell wall, similar to those described for the purple sulfur bacteria Ectothiorhodospira. These bacteria are found inside the cyanobacterial bundle, enclosed by the cyanobacterial sheath. Detailed transmission electron microscopical analyses carried out in horizontal sections of the upper 1.5 mm of the cyanobacterial mat show this cyanobacterial-purple bacterial association at depths of 300-1200 micrometers, corresponding to the zone below that of maximal oxygenic photosynthesis. Sharp gradients of oxygen and sulfide are established during the day at this microzone in the two cyanobacterial mats studied. The close association, the distribution pattern of this association and preliminary physiological experiments suggest a co-metabolism of sulfur by the two-membered community. This probable new genus of purple bacteria may also grow photoheterotrophically using organic carbon excreted by the cyanobacterium. Since the chemical gradients in the entire photic zone fluctuate widely in a diurnal cycle, both types of metabolism probably take place. During the morning and afternoon, sulfide migrates up to the photic zone allowing photoautotrophic metabolism with sulfide as the electron donor. During the day the photic zone is highly oxygenated and the purple bacteria may either use oxidized species of sulfur such as elemental sulfur and thiosulfate in the photoautotrophic mode or grow photoheterotrophically using organic carbon excreted by M. chthonoplastes. The new type of filamentous purple sulfur

  4. Occurrence and origin of mono-, di-, and trimethylalkanes in modern and Holocene cyanobacterial mats from Abu Dhabi, United Arab Emirates

    SciTech Connect

    Kenig, F. |; Huc, A.Y.; Rijpstra, W.I.C.

    1995-07-01

    n-Alkanes, highly branched isoprenoids, monomethylalkanes (MMAs), dimethyalkanes (DMAs), and trimethylalkanes (TMAs) are the most abundant components in the hydrocarbon fractions of extracts of four modern and two Holocene cyanobacterial mats ({approximately}1500 and 5110 {+-} 170 y BP) collected in Abu Dhabi (United Arab Emirates). The homologous families of MMAs, DMAs, and TMAs were identified by comparison of mass spectral and relative retention time data with published data. DMAs were also identified by synthesis of authentic standards, 3,9-dimethyltricosane, 5,9-dimethyltricosane, and 11,15-dimethylheptacosane. MMAs, DMAs, and TMAs of the cyanobacterial mats can be separated into two groups on the basis of their distribution patterns and structures. MMAs and DMAs in the C{sub 16}-C{sub 22} range are characterized by methyl substituents mainly located at C-6 (or {omega}6) and C-7 (or {omega}7) and are derived from cyanobacteria. They are relatively abundant components in the modern cyanobacterial mats, but with increasing age of the mats they become much less abundant. On the contrary MMAs, DMAs, and TMAs in the C{sub 24}-C{sub 45} range are exclusively found in the Holocene cyanobacterial mats. Their longest chains mainly contain an odd number of carbon atoms and they always carry the methyl substituents at odd numbered carbon atoms. The similarity in composition of this very specific group of branched alkanes with that encountered in insect epicuticular waxes suggests that these sedimentary hydrocarbons originate from insects, which probably grazed on the cyanobacterial mats.

  5. The cyanobacterial CCM as a source of genes for improving photosynthetic CO2 fixation in crop species.

    PubMed

    Price, G Dean; Pengelly, Jasper J L; Forster, Britta; Du, Jiahui; Whitney, Spencer M; von Caemmerer, Susanne; Badger, Murray R; Howitt, Susan M; Evans, John R

    2013-01-01

    Crop yields need to nearly double over the next 35 years to keep pace with projected population growth. Improving photosynthesis, via a range of genetic engineering strategies, has been identified as a promising target for crop improvement with regard to increased photosynthetic yield and better water-use efficiency (WUE). One approach is based on integrating components of the highly efficient CO(2)-concentrating mechanism (CCM) present in cyanobacteria (blue-green algae) into the chloroplasts of key C(3) crop plants, particularly wheat and rice. Four progressive phases towards engineering components of the cyanobacterial CCM into C(3) species can be envisaged. The first phase (1a), and simplest, is to consider the transplantation of cyanobacterial bicarbonate transporters to C(3) chloroplasts, by host genomic expression and chloroplast targeting, to raise CO(2) levels in the chloroplast and provide a significant improvement in photosynthetic performance. Mathematical modelling indicates that improvements in photosynthesis as high as 28% could be achieved by introducing both of the single-gene, cyanobacterial bicarbonate transporters, known as BicA and SbtA, into C(3) plant chloroplasts. Part of the first phase (1b) includes the more challenging integration of a functional cyanobacterial carboxysome into the chloroplast by chloroplast genome transformation. The later three phases would be progressively more elaborate, taking longer to engineer other functional components of the cyanobacterial CCM into the chloroplast, and targeting photosynthetic and WUE efficiencies typical of C(4) photosynthesis. These later stages would include the addition of NDH-1-type CO(2) pumps and suppression of carbonic anhydrase and C(3) Rubisco in the chloroplast stroma. We include a score card for assessing the success of physiological modifications gained in phase 1a.

  6. The effect of rock composition on cyanobacterial weathering of crystalline basalt and rhyolite.

    PubMed

    Olsson-Francis, K; Simpson, A E; Wolff-Boenisch, D; Cockell, C S

    2012-09-01

    The weathering of volcanic rocks contributes significantly to the global silicate weathering budget, effecting carbon dioxide drawdown and long-term climate control. The rate of chemical weathering is influenced by the composition of the rock. Rock-dwelling micro-organisms are known to play a role in changing the rate of weathering reactions; however, the influence of rock composition on bio-weathering is unknown. Cyanobacteria are known to be a ubiquitous surface taxon in volcanic rocks. In this study, we used a selection of fast and slow growing cyanobacterial species to compare microbial-mediated weathering of bulk crystalline rocks of basaltic and rhyolitic composition, under batch conditions. Cyanobacterial growth caused an increase in the pH of the medium and an acceleration of rock dissolution compared to the abiotic controls. For example, Anabaena cylindrica increased the linear release rate (R(i)(l)) of Ca, Mg, Si and K from the basalt by more than fivefold (5.21-12.48) and increased the pH of the medium by 1.9 units. Although A. cylindrica enhanced rhyolite weathering, the increase in R(i)(l) was less than threefold (2.04-2.97) and the pH increase was only 0.83 units. The R(i)(l) values obtained with A. cylindrica were at least ninefold greater with the basalt than the rhyolite, whereas in the abiotic controls, the difference was less than fivefold. Factors accounting for the slower rate of rhyolite weathering and lower biomass achieved are likely to include the higher content of quartz, which has a low rate of weathering and lower concentrations of bio-essential elements, such as, Ca, Fe and Mg, which are known to be important in controlling cyanobacterial growth. We show that at conditions where weathering is favoured, biota can enhance the difference between low and high Si-rock weathering. Our data show that cyanobacteria can play a significant role in enhancing rock weathering and likely have done since they evolved on the early Earth.

  7. A Comprehensive Study of Cyanobacterial Morphological and Ecological Evolutionary Dynamics through Deep Geologic Time

    PubMed Central

    Harmon, Luke J.; Blank, Carrine E.

    2016-01-01

    Cyanobacteria have exerted a profound influence on the progressive oxygenation of Earth. As a complementary approach to examining the geologic record—phylogenomic and trait evolutionary analyses of extant species can lead to new insights. We constructed new phylogenomic trees and analyzed phenotypic trait data using novel phylogenetic comparative methods. We elucidated the dynamics of trait evolution in Cyanobacteria over billion-year timescales, and provide evidence that major geologic events in early Earth’s history have shaped—and been shaped by—evolution in Cyanobacteria. We identify a robust core cyanobacterial phylogeny and a smaller set of taxa that exhibit long-branch attraction artifacts. We estimated the age of nodes and reconstruct the ancestral character states of 43 phenotypic characters. We find high levels of phylogenetic signal for nearly all traits, indicating the phylogeny carries substantial predictive power. The earliest cyanobacterial lineages likely lived in freshwater habitats, had small cell diameters, were benthic or sessile, and possibly epilithic/endolithic with a sheath. We jointly analyzed a subset of 25 binary traits to determine whether rates of trait evolution have shifted over time in conjunction with major geologic events. Phylogenetic comparative analysis reveal an overriding signal of decreasing rates of trait evolution through time. Furthermore, the data suggest two major rate shifts in trait evolution associated with bursts of evolutionary innovation. The first rate shift occurs in the aftermath of the Great Oxidation Event and “Snowball Earth” glaciations and is associated with decrease in the evolutionary rates around 1.8–1.6 Ga. This rate shift seems to indicate the end of a major diversification of cyanobacterial phenotypes–particularly related to traits associated with filamentous morphology, heterocysts and motility in freshwater ecosystems. Another burst appears around the time of the Neoproterozoic

  8. Organo-mineral imprints in fossil cyanobacterial mats of an Antarctic lake

    NASA Astrophysics Data System (ADS)

    Javaux, E.; Lepot, K.; Deremiens, L.; Namsaraev, Z.; Compere, P.; Gerard, E.; Verleyen, E.; Tavernier, I.; Hodgson, D.; Vyverman, W.; Wilmotte, A.

    2010-12-01

    Lacustrine microbial mats in Antarctic ice-free oases are considered to be modern analogues of early microbial ecosystems because they are dominated by cyanobacteria that need to cope with elevated UV radiation during summer by producing protective compounds such as UV-screening pigments. These microbial consortia offer a unique opportunity to (i) identify biogeochemical signatures to study the fossil record of microorganisms, and (ii) better understand their imprint mineral record. We studied sediment cores from a meromictic brackish-water lake, Kobachi Ike, Skarvsnes Peninsula, Lützow Holm Bay, East Antarctica, where primary production is dominated by photosynthetic benthic communities. The faintly to finely laminated (stromatolitic) sediments include variable amounts of organic-rich laminae, micritic carbonate, clays and silicate sand. We studied the microstructure and chemistry of organo-mineral associations in a suite of sediments ranging in age from several tens to ca. 3500 years. We examined Os- and U- stained polished resin-embedded sediments in a scanning electron microscope (SEM). We imaged photosynthetic pigments of microorganisms in fluorescence by confocal laser scanning microscopy (CLSM). We analyzed organic matter chemistry in demineralized sediments and cultured cyanobacteria using Fourier-Transform Infrared (FTIR) spectromicroscopy. Molecular analyses of fossil cyanobacterial DNA were performed using Denaturating Gradient Gel Electrophoresis of partial 16S rRNA genes and sequencing. SEM revealed an intimate association between nanostructured Ca-carbonate peloids, fossil cell clusters resembling colonies of unicellular coccoid cyanobacteria, and cell-like imprints preserved in nanocarbonates. Diffuse organic matter (kerogen or EPS) is associated with nanoclays to form a laminae-building network around the carbonates. These organo-mineral microstructures strongly resemble those of the 2.7 Gyrs old Tumbiana stromatolites. CLSM imaging and fossil DNA

  9. A Comprehensive Study of Cyanobacterial Morphological and Ecological Evolutionary Dynamics through Deep Geologic Time.

    PubMed

    Uyeda, Josef C; Harmon, Luke J; Blank, Carrine E

    2016-01-01

    Cyanobacteria have exerted a profound influence on the progressive oxygenation of Earth. As a complementary approach to examining the geologic record-phylogenomic and trait evolutionary analyses of extant species can lead to new insights. We constructed new phylogenomic trees and analyzed phenotypic trait data using novel phylogenetic comparative methods. We elucidated the dynamics of trait evolution in Cyanobacteria over billion-year timescales, and provide evidence that major geologic events in early Earth's history have shaped-and been shaped by-evolution in Cyanobacteria. We identify a robust core cyanobacterial phylogeny and a smaller set of taxa that exhibit long-branch attraction artifacts. We estimated the age of nodes and reconstruct the ancestral character states of 43 phenotypic characters. We find high levels of phylogenetic signal for nearly all traits, indicating the phylogeny carries substantial predictive power. The earliest cyanobacterial lineages likely lived in freshwater habitats, had small cell diameters, were benthic or sessile, and possibly epilithic/endolithic with a sheath. We jointly analyzed a subset of 25 binary traits to determine whether rates of trait evolution have shifted over time in conjunction with major geologic events. Phylogenetic comparative analysis reveal an overriding signal of decreasing rates of trait evolution through time. Furthermore, the data suggest two major rate shifts in trait evolution associated with bursts of evolutionary innovation. The first rate shift occurs in the aftermath of the Great Oxidation Event and "Snowball Earth" glaciations and is associated with decrease in the evolutionary rates around 1.8-1.6 Ga. This rate shift seems to indicate the end of a major diversification of cyanobacterial phenotypes-particularly related to traits associated with filamentous morphology, heterocysts and motility in freshwater ecosystems. Another burst appears around the time of the Neoproterozoic Oxidation Event in

  10. Collaborative Research Program on Seafood Toxins

    DTIC Science & Technology

    1988-08-14

    AD-A 2 6 0 073 9 COLLABORATIVE RESEARCH PROGRAM ON SEAFOOD TOXINS FINAL REPORT SAMUEL W. PAGE D TI. DCTI AUGUST 14, 1988 JAN26 1993Wý--- Supported by...NO. NO. 3M- NO. ACCESSION NO. _ 62787A 62787A871 I A96 11. TITLE (Include Security Clastficarion) (U) Collaborative Research Program on Seafood Toxins ...FIELD GROUP SUB-6ROUP RA 1; Workshop; LHI; Seafood toxins ; Assays; BD 07_ 04 nL 2! 19. ABSTRACT (Continue on reverse of necessary and identi(y by

  11. Emerging insights into the biology of typhoid toxin.

    PubMed

    Fowler, Casey C; Chang, Shu-Jung; Gao, Xiang; Geiger, Tobias; Stack, Gabrielle; Galán, Jorge E

    2017-02-14

    Typhoid toxin is a unique A2B5 exotoxin and an important virulence factor for Salmonella Typhi, the cause of typhoid fever. In the decade since its initial discovery, great strides have been made in deciphering the unusual biological program of this toxin, which is fundamentally different from related toxins in many ways. Purified typhoid toxin administered to laboratory animals causes many of the symptoms of typhoid fever, suggesting that typhoid toxin is a central factor in this disease. Further advances in understanding the biology of this toxin will help guide the development of badly needed diagnostics and therapeutic interventions that target this toxin to detect, prevent or treat typhoid fever.

  12. Clostridium perfringens type A-E toxin plasmids.

    PubMed

    Freedman, John C; Theoret, James R; Wisniewski, Jessica A; Uzal, Francisco A; Rood, Julian I; McClane, Bruce A

    2015-05-01

    Clostridium perfringens relies upon plasmid-encoded toxin genes to cause intestinal infections. These toxin genes are associated with insertion sequences that may facilitate their mobilization and transfer, giving rise to new toxin plasmids with common backbones. Most toxin plasmids carry a transfer of clostridial plasmids locus mediating conjugation, which likely explains the presence of similar toxin plasmids in otherwise unrelated C. perfringens strains. The association of many toxin genes with insertion sequences and conjugative plasmids provides virulence flexibility when causing intestinal infections. However, incompatibility issues apparently limit the number of toxin plasmids maintained by a single cell.

  13. Clostridium perfringens type A–E toxin plasmids

    PubMed Central

    Freedman, John C.; Theoret, James R.; Wisniewski, Jessica A.; Uzal, Francisco A.; Rood, Julian I.; McClane, Bruce A.

    2014-01-01

    Clostridium perfringens relies upon plasmid-encoded toxin genes to cause intestinal infections. These toxin genes are associated with insertion sequences that may facilitate their mobilization and transfer, giving rise to new toxin plasmids with common backbones. Most toxin plasmids carry a transfer of clostridial plasmids locus mediating conjugation, which likely explains the presence of similar toxin plasmids in otherwise unrelated C. perfringens strains. The association of many toxin genes with insertion sequences and conjugative plasmids provides virulence flexibility when causing intestinal infections. However, incompatibility issues apparently limit the number of toxin plasmids maintained by a single cell. PMID:25283728

  14. Presence of Potential Toxin-Producing Cyanobacteria in an Oligo-Mesotrophic Lake in Baltic Lake District, Germany: An Ecological, Genetic and Toxicological Survey

    PubMed Central

    Dadheech, Pawan K.; Selmeczy, Géza B.; Vasas, Gábor; Padisák, Judit; Arp, Wolfgang; Tapolczai, Kálmán; Casper, Peter; Krienitz, Lothar

    2014-01-01

    Massive developments of potentially toxic cyanobacteria in Lake Stechlin, an oligo-mesotrophic lake in the Baltic Lake District of Germany raised concerns about toxic contamination of these important ecosystems. Field samples in the phase of mass developments of cyanobacteria were used for genetic and toxicological analyses. Microcystins and microcystin genes were detected in field samples of the lake for the first time. However, the toxins were not produced by the dominant taxa (Dolichospermum circinale and Aphanizomenon flos-aquae) but by taxa, which were present only in low biomass in the samples (Microcystis cf. aeruginosa and Planktothrix rubescens). The phytoplankton successions during the study period revealed an increase of cyanobacterial populations. The findings contribute to the changes that have been investigated in Lake Stechlin since the mid-1990s. The possible reasons behind these developments may be climate change, special weather conditions and an increased nutrient pool. PMID:25268981

  15. Presence of potential toxin-producing cyanobacteria in an oligo-mesotrophic lake in Baltic Lake District, Germany: an ecological, genetic and toxicological survey.

    PubMed

    Dadheech, Pawan K; Selmeczy, Géza B; Vasas, Gábor; Padisák, Judit; Arp, Wolfgang; Tapolczai, Kálmán; Casper, Peter; Krienitz, Lothar

    2014-09-29

    Massive developments of potentially toxic cyanobacteria in Lake Stechlin, an oligo-mesotrophic lake in the Baltic Lake District of Germany raised concerns about toxic contamination of these important ecosystems. Field samples in the phase of mass developments of cyanobacteria were used for genetic and toxicological analyses. Microcystins and microcystin genes were detected in field samples of the lake for the first time. However, the toxins were not produced by the dominant taxa (Dolichospermum circinale and Aphanizomenon flos-aquae) but by taxa, which were present only in low biomass in the samples (Microcystis cf. aeruginosa and Planktothrix rubescens). The phytoplankton successions during the study period revealed an increase of cyanobacterial populations. The findings contribute to the changes that have been investigated in Lake Stechlin since the mid-1990s. The possible reasons behind these developments may be climate change, special weather conditions and an increased nutrient pool.

  16. Investigating the role of solanapyrone toxins in Ascochyta blight using toxin-deficient mutants of Asochyta rabiei

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ascochyta rabiei, the causal agent of Ascochyta blight of chickpea, produces solanapyrone toxins (solanapyrone A, B and C). However, very little is known about the genetics of toxin production and the role of the toxins in pathogenesis. Generating mutants deficient in the toxin biosynthesis would p...

  17. The Interactions of Human Neutrophils with Shiga Toxins and Related Plant Toxins: Danger or Safety?

    PubMed Central

    Brigotti, Maurizio

    2012-01-01

    Shiga toxins and ricin are well characterized similar toxins belonging to quite different biological kingdoms. Plant and bacteria have evolved the ability to produce these powerful toxins in parallel, while humans have evolved a defense system that recognizes molecular patterns common to foreign molecules through specific receptors expressed on the surface of the main actors of innate immunity, namely monocytes and neutrophils. The interactions between these toxins and neutrophils have been widely described and have stimulated intense debate. This paper is aimed at reviewing the topic, focusing particularly on implications for the pathogenesis and diagnosis of hemolytic uremic syndrome. PMID:22741061

  18. Circadian rhythms. Atomic-scale origins of slowness in the cyanobacterial circadian clock.

    PubMed

    Abe, Jun; Hiyama, Takuya B; Mukaiyama, Atsushi; Son, Seyoung; Mori, Toshifumi; Saito, Shinji; Osako, Masato; Wolanin, Julie; Yamashita, Eiki; Kondo, Takao; Akiyama, Shuji

    2015-07-17

    Circadian clocks generate slow and ordered cellular dynamics but consist of fast-moving bio-macromolecules; consequently, the origins of the overall slowness remain unclear. We identified the adenosine triphosphate (ATP) catalytic region [adenosine triphosphatase (ATPase)] in the amino-terminal half of the clock protein KaiC as the minimal pacemaker that controls the in vivo frequency of the cyanobacterial clock. Crystal structures of the ATPase revealed that the slowness of this ATPase arises from sequestration of a lytic water molecule in an unfavorable position and coupling of ATP hydrolysis to a peptide isomerization with high activation energy. The slow ATPase is coupled with another ATPase catalyzing autodephosphorylation in the carboxyl-terminal half of KaiC, yielding the circadian response frequency of intermolecular interactions with other clock-related proteins that influences the transcription and translation cycle.

  19. Distinguishing the cyanobacterial neurotoxin β-N-methylamino-L-alanine (BMAA) from other diamino acids.

    PubMed

    Banack, S A; Metcalf, J S; Spáčil, Z; Downing, T G; Downing, S; Long, A; Nunn, P B; Cox, P A

    2011-04-01

    β-N-methylamino-L-alanine (BMAA) is produced by diverse taxa of cyanobacteria, and has been detected by many investigators who have searched for it in cyanobacterial blooms, cultures and collections. Although BMAA is distinguishable from proteinogenic amino acids and its isomer 2,4-DAB using standard chromatographic and mass spectroscopy techniques routinely used for the analysis of amino acids, we studied whether BMAA could be reliably distinguished from other diamino acids, particularly 2,6-diaminopimelic acid which has been isolated from the cell walls of many bacterial species. We used HPLC-FD, UHPLC-UV, UHPLC-MS, and triple quadrupole tandem mass spectrometry (UHPLC-MS/MS) to differentiate BMAA from the diamino acids 2,6-diaminopimelic acid, N-2(amino)ethylglycine, lysine, ornithine, 2,4-diaminosuccinic acid, homocystine, cystine, tryptophan, as well as other amino acids including asparagine, glutamine, and methionine methylsulfonium.

  20. Relationship between cyanobacterial biomass and total microcystin-LR levels in drinking and recreational water.

    PubMed

    Kim, Baik-Ho; Hwang, Soon-Jin; Park, Myung-Hwan; Kim, Yong-Jae

    2010-11-01

    Cyanobacterial biomass, chlorophyll-a, and microcystin-LR levels were monitored in drinking and recreational water in Seoul, South Korea and three satellite cities from Oct 2006 to Aug 2007. Total microcystin-LR was the sum of particulate and dissolved microcystin. Except during cold periods, toxic cyanobacteria, including Anabaena flos-aquae, were found at all sites. The total microcystin-LR levels were below guideline danger levels (<1.0 μg/L) except one time (1.27 μg/L in October), whereas chl-a (111.7 μg/L) and cell levels (2.6 × 10⁵ cells/mL) were at 'vigilance' and 'alert' levels for drinking water and at 'guidance' level for recreational water, respectively. Discrepancies in these parameters may thus lead to frequent unnecessary alerts, thereby increasing water management costs.

  1. Cyanobacterial harmful algal blooms and U.S. Geological Survey science capabilities

    USGS Publications Warehouse

    Graham, Jennifer L.; Dubrovsky, Neil M.; Eberts, Sandra M.

    2016-09-29

    Cyanobacterial harmful algal blooms (CyanoHABs) are increasingly a global concern because CyanoHABs pose a threat to human and aquatic ecosystem health and cause economic damages. Despite advances in scientific understanding of cyanobacteria and associated compounds, many unanswered questions remain about occurrence, environmental triggers for toxicity, and the ability to predict the timing, duration, and toxicity of CyanoHABs. U.S. Geological Survey (USGS) scientists are leading a diverse range of studies to address CyanoHAB issues in water bodies throughout the United States, using a combination of traditional methods and emerging technologies, and in collaboration with numerous partners. By providing practical applications of cutting edge CyanoHAB research, USGS studies have advanced scientific understanding, enabling the development of approaches to help protect ecological and human health.

  2. Hypersaline cyanobacterial mats as indicators of elevated tropical hurricane activity and associated climate change.

    PubMed

    Paerl, Hans W; Steppe, Timothy F; Buchan, Kenneth C; Potts, Malcolm

    2003-03-01

    The Atlantic hurricanes of 1999 caused widespread environmental damage throughout the Caribbean and US mid-Atlantic coastal regions. However, these storms also proved beneficial to certain microbial habitats; specifically, cyanobacteria-dominated mats. Modern mats represent the oldest known biological communities on earth, stromatolites. Contemporary mats are dominant biological communities in the hypersaline Bahamian lakes along the Atlantic hurricane track. We examined the impacts of varying levels of hypersalinity on 2 processes controlling mat growth, photosynthesis and nitrogen fixation, in Salt Pond, San Salvador Island, Bahamas. Hypersalinity (> 5 times seawater salinity) proved highly inhibitory to these processes. Freshwater input from Hurricane Floyd and other large storms alleviated this salt-inhibition. A predicted 10 to 40 year increase in Atlantic hurricane activity accompanied by more frequent "freshening" events will enhance mat productivity, CO2 sequestration and nutrient cycling. Cyanobacterial mats are sensitive short- and long-term indicators of climatic and ecological changes impacting these and other waterstressed environments.

  3. Community phylogenetic diversity of cyanobacterial mats associated with geothermal springs along a tropical intertidal gradient.

    PubMed

    Jing, Hongmei; Lacap, Donnabella C; Lau, Chui Yim; Pointing, Stephen B

    2006-04-01

    The 16S rRNA gene-defined bacterial diversity of tropical intertidal geothermal vents subject to varying degrees of seawater inundation was investigated. Shannon-Weaver diversity estimates of clone library-derived sequences revealed that the hottest pools located above the mean high-water mark that did not experience seawater inundation were most diverse, followed by those that were permanently submerged below the mean low-water mark. Pools located in the intertidal were the least biodiverse, and this is attributed to the fluctuating conditions caused by periodic seawater inundation rather than physicochemical conditions per se. Phylogenetic analysis revealed that a ubiquitous Oscillatoria-like phylotype accounted for 83% of clones. Synechococcus-like phylotypes were also encountered at each location, whilst others belonging to the Chroococcales, Oscillatoriales, and other non-phototrophic bacteria occurred only at specific locations along the gradient. All cyanobacterial phylotypes displayed highest phylogenetic affinity to terrestrial thermophilic counterparts rather than marine taxa.

  4. [Botulinum toxin in disabling dermatological diseases].

    PubMed

    Messikh, R; Atallah, L; Aubin, F; Humbert, P

    2009-05-01

    Botulinum toxin could represent nowadays a new treatment modality especially for cutaneous conditions in course of which conventional treatments remain unsuccessful. Besides palmar and plantar hyperhidrosis, botulinum toxin has demonstrated efficacy in different conditions associated with hyperhidrosis, such as dyshidrosis, multiple eccrine hidrocystomas, hidradenitis suppurativa, Frey syndrome, but also in different conditions worsened by hyperhidrosis such as Hailey-Hailey disease, Darier disease, inversed psoriasis, aquagenic palmoplantar keratoderma, pachyonychia congenital. Moreover, different cutaneous conditions associated with sensitive disorders and/or neurological involvements could benefit from botulinum toxin, for example anal fissures, leg ulcers, lichen simplex, notalgia paresthetica, vestibulitis. Endly, a case of cutis laxa was described where the patient was improved by cutaneous injections of botulinum toxin.

  5. How Parkinsonian Toxins Dysregulate the Autophagy Machinery

    PubMed Central

    Dagda, Ruben K.; Das Banerjee, Tania; Janda, Elzbieta

    2013-01-01

    Since their discovery, Parkinsonian toxins (6-hydroxydopamine, MPP+, paraquat, and rotenone) have been widely employed as in vivo and in vitro chemical models of Parkinson’s disease (PD). Alterations in mitochondrial homeostasis, protein quality control pathways, and more recently, autophagy/mitophagy have been implicated in neurotoxin models of PD. Here, we highlight the molecular mechanisms by which different PD toxins dysregulate autophagy/mitophagy and how alterations of these pathways play beneficial or detrimental roles in dopamine neurons. The convergent and divergent effects of PD toxins on mitochondrial function and autophagy/mitophagy are also discussed in this review. Furthermore, we propose new diagnostic tools and discuss how pharmacological modulators of autophagy/mitophagy can be developed as disease-modifying treatments for PD. Finally, we discuss the critical need to identify endogenous and synthetic forms of PD toxins and develop efficient health preventive programs to mitigate the risk of developing PD. PMID:24217228

  6. [Cyclic imine toxin gymnodimine: a review].

    PubMed

    Liu, Ren-yan; Liang, Yu-bo

    2009-09-01

    Gymnodimine (GYM), an algal toxin first detected from New Zealand oysters in 1994, is identified as a cyclic imine toxin and produced by Karenia selliformis, with imino nitrogen attached on loop-coil. Imine is the poisonous functional group of the toxin. GYM has a low oral toxicity, but its acute lethal toxicity of intra-peritoneal injection for mice is very high. Up to now, few reports have been published on the detailed information about the toxicity mechanism of GYM. Based on limited literatures, this paper reviewed the GYM's structure, producer, toxicity mechanism, carrying animals, geological distribution, degradation metabolism, dose-effect relation, and risk evaluation, and proposed the further research directions on algal toxin.

  7. INVESTIGATOIN OF CYANOBACTERIA TOXINS IN WATER

    EPA Science Inventory

    Introduction:

    Approximately 80 alkaloid and cyclic peptide toxins produced by various freshwater and marine cyanobacteria (blue-green algae) have been identified and their structures determined. The U. S. Environmental Protection Agency has identified two neurotoxin alkalo...

  8. Clostridium difficile and C. difficile Toxin Testing

    MedlinePlus

    ... C diff antigen; GDH Formal name: Clostridium difficile Culture; C. difficile Toxin, A and B; C. difficile Cytotoxin Assay; Glutamate Dehydrogenase Test Related tests: Stool Culture ; O&P At a Glance Test Sample The ...

  9. Hemolytic anemia caused by chemicals and toxins

    MedlinePlus

    ... Rho immune globulin (WinRho) Ribavirin Snake bites (some snake venom contains hemolytic toxins ) Sulfonamides Sulfones This list is not all-inclusive. Alternative Names ... Review Date 2/12/2016 Updated ...

  10. [Potential antinociceptive mechanisms of botulinum toxin].

    PubMed

    Aoki, K R; Francis, J; Jost, W H

    2006-09-01

    Botulinum toxin has been used in pain therapy for several years. Its application in migraine and headaches is particularly interesting. Clinical results have not yet been definitely conclusive, and a uniform model of the mode of action has not been established either. Apart from a purely muscular effect, a direct antinociceptive effect of botulinum toxin has been found in patients, in the preclinical model, and in a clinical pain model. This is contradicted by negative observations in the clinical model of pain, which might be related to methodological deficits. Further basics need to be worked out before arriving at any final result. Clinical studies with patients and pain models should then follow. Studying botulinum toxin within the context of pain will also provide many new insights into pain therapy in general. In which pain model botulinum toxin may play a role in the future, has to be awaited.

  11. Metagenomic Study of Iron Homeostasis in Iron Depositing Hot Spring Cyanobacterial Community

    NASA Technical Reports Server (NTRS)

    Brown, I.; Franklin H.; Tringe, S. G.; Klatt, C. G.; Bryant, D. A.; Sarkisova, S. A.; Guevara, M.

    2010-01-01

    Introduction: It is not clear how an iron-rich thermal hydrosphere could be hospitable to cyanobacteria, since reduced iron appears to stimulate oxidative stress in all domains of life and particularly in oxygenic phototrophs. Therefore, metagenomic study of cyanobacterial community in iron-depositing hot springs may help elucidate how oxygenic prokaryotes can withstand the extremely high concentrations of reactive oxygen species (ROS) produced by interaction between environmental Fe2+ and O2. Method: Anchor proteins from various species of cyanobacteria and some anoxygenic phototrophs were selected on the basis of their hypothetical role in Fe homeostasis and the suppression of oxidative stress and were BLASTed against the metagenomes of iron-depositing Chocolate Pots and freshwater Mushroom hot springs. Results: BLASTing proteins hypothesized to be involved in Fe homeostasis against the microbiomes from the two springs revealed that iron-depositing hot spring has a greater abundance of defensive proteins such as bacterioferritin comigratory protein (Bcp) and DNA-binding Ferritin like protein (Dps) than a fresh-water hot spring. One may speculate that the abundance of Bcp and Dps in an iron-depositing hot spring is connected to the need to suppress oxidative stress in bacteria inhabiting environments with high Fe2+ concnetration. In both springs, Bcp and Dps are concentrated within the cyanobacterial fractions of the microbial community (regardless of abundance). Fe3+ siderophore transport (from the transport system permease protein query) may be less essential to the microbial community of CP because of the high [Fe]. Conclusion: Further research is needed to confirm that these proteins are unique to photoautotrophs such as those living in iron-depositing hot spring.

  12. Different physiological and photosynthetic responses of three cyanobacterial strains to light and zinc.

    PubMed

    Xu, Kui; Juneau, Philippe

    2016-01-01

    Zinc pollution of freshwater aquatic ecosystems is a problem in many countries, although its specific effects on phytoplankton may be influenced by other environmental factors. Light intensity varies continuously under natural conditions depending on the cloud cover and the season, and the response mechanisms of cyanobacteria to high zinc stress under different light conditions are not yet well understood. We investigated the effects of high zinc concentrations on three cyanobacterial strains (Microcystis aeruginosa CPCC299, M. aeruginosa CPCC632, and Synechocystis sp. FACHB898) grown under two light regimes. Under high light condition (HL), the three cyanobacterial strains increased their Car/Chl a ratios and non-photochemical quenching (NPQ), with CPCC299 showing the highest growth rate-suggesting a greater ability to adapt to those conditions as compared to the other two strains. Under high zinc concentrations the values of maximal (ФM) and operational (Ф'M) photosystem II quantum yields, photosystem I quantum yield [Y(I)], and NPQ decreased. The following order of sensitivity to high zinc was established for the three strains studied: CPCC299>CPCC632>FACHB898. These different sensitivities can be partly explained by the higher internal zinc content observed in CPCC299 as compared to the other two strains. HL increased cellular zinc content and therefore increased zinc toxicity in both M. aeruginosa strains, although to a greater extent in CPCC299 than in CPCC632. Car/Chl a ratios decreased with high zinc concentrations under HL only in CPCC299, but not under low light (LL) conditions for all the studied strains, suggesting that the three strains have different response mechanisms to high zinc stress when grown under different light regimes. We demonstrated that interactions between light intensity and zinc need to be considered when studying the bloom dynamics of cyanobacteria in freshwater ecosystems.

  13. Spatial and temporal distribution of cyanobacterial soil crusts in the Kalahari: Implications for soil surface properties

    NASA Astrophysics Data System (ADS)

    Thomas, A. D.; Dougill, A. J.

    2007-03-01

    Localised patterns of erosion and deposition in vegetated semi-arid rangelands have been shown to influence ecological change and biogeochemical cycles. In the flat, vegetated Kalahari rangelands of Southern Africa the factors regulating erodibility of the fine sand soils and the erosivity of wind regimes require further investigation. This paper reports on the spatial and temporal patterns of cyanobacterial soil crust cover from ten sites at five sampling locations in the semi-arid Kalahari and discusses the likely impact on factors regulating surface erodibility and erosivity. Cyanobacterial soil crust cover on Kalahari Sand varied between 11% and 95% of the ground surface and was higher than previously reported. Cover was inversely related to grazing with the lowest crust cover found close to boreholes and the highest in the Game Reserve and Wildlife Management Zone. In grazed areas, crusts form under the protective canopies of the thorny shrub Acacia mellifera. Fenced plot data showed that crusts recover quickly from disturbance, with a near complete surface crust cover forming within 15 months of disturbance. Crust development is restricted by burial by wind blown sediment and by raindrop impact. Crusts had significantly greater organic matter and total nitrogen compared to unconsolidated surfaces. Crusts also significantly increased the compressive strength of the surface (and thus decreased erodibility) and changed the surface roughness. Establishing exactly how these changes affect aeolian erosion requires further process-based studies. The proportion of shear velocity acting on the surface in this complex mixed bush-grass-crust environment will be the key to understanding how crusts affect erodibility.

  14. Comparative assessment of the efficacy of bacterial and cyanobacterial phytohormones in plant tissue culture.

    PubMed

    Hussain, Anwar; Hasnain, Shahida

    2012-04-01

    Efficient callus and explant regeneration medium, using microbial extract (SPE purified) or supernatant has been formulated for Brassica oleracea L. var. capitata. Two cyanobacterial strains (Anabaena sp. Ck1 and Chroococcidiopsis sp. Ck4) and two bacterial strains, (Pseudomonas spp. Am3 and Am4) known to produce a number of cytokinins, tZ, cZ, ZR, DHZR and IAA were selected for the media formulation. Supernatant from strains with high cytokinin to IAA ratio, including Pseudomonas aeruginosa Am3 (2.08) and Chroococcidiopsis sp. Ck4 (0.8) efficiently induced compact calli which were turned green upon exposure to light. The strains producing lower cytokinins to IAA ratio (0.11-0.13) on the other hand induced friable callus which were unable to regenerate on the selected media combinations. Leaf, stem and root explants of Brassica oleracea L. regenerated on MS medium supplemented with phytohormones from microbial origin with efficiency comparable to standard cytokinins and IAA. Supplements from cyanobacterial origin proved to be the best for induction of adventitious roots and shoots on internodal and petiolar segments. Hypocotyl explants however, responded well on MS supplemented with bacterial metabolites. Induction of adventitious shoots on root explants was supported by phytohormones from both origin equally well. Callus induction on the seeds and regeneration of shoots on calli was also observed. Cyanobacteria based media were more efficient to induce calli capable of regeneration upon exposure to light. Internodal explants were highly amenable to regenerate shoot and roots simultaneously. Root explants were the less successful to regenerate shoots.

  15. Predicting the vulnerability of reservoirs to poor water quality and cyanobacterial blooms.

    PubMed

    Leigh, Catherine; Burford, Michele A; Roberts, David T; Udy, James W

    2010-08-01

    Cyanobacterial blooms in drinking water reservoirs present a major ecosystem functioning and human health issue. The ability to predict reservoir vulnerability to these blooms would provide information critical for decision making, hazard prevention and management. We developed a new, comparative index of vulnerability based on simple measures of reservoir and catchment characteristics, rather than water quality data, which were instead used to test the index's effectiveness. Testing was based on water quality data collected over a number of seasons and years from 15 drinking water reservoirs in subtropical, southeast Queensland. The index correlated significantly and strongly with algal cell densities, including potentially toxic cyanobacteria, as well as with the proportions of cyanobacteria in summer months. The index also performed better than each of the measures of reservoir and catchment characteristics alone, and as such, was able to encapsulate the physical characteristics of subtropical reservoirs, and their catchments, into an effective indicator of the vulnerability to summer blooms. This was further demonstrated by calculating the index for a new reservoir to be built within the study region. Under planned dimensions and land use, a comparatively high level of vulnerability was reached within a few years. However, the index score and the number of years taken to reach a similar level of vulnerability could be reduced simply by decreasing the percentage of grazing land cover via revegetation within the catchment. With climate change, continued river impoundment and the growing demand for potable water, our index has potential decision making benefits when planning future reservoirs to reduce their vulnerability to cyanobacterial blooms.

  16. THE ELECTRICAL CHARGE OF TOXIN AND ANTITOXIN.

    PubMed

    Field, C W; Teague, O

    1907-01-23

    1. Both diphtheria and tetanus toxin and their antitoxins arc electro-positive, that is, they pass to the cathode under the influence of an electric current. 2. The character of the charge is not altered by a change in the reaction of the solvent. 3. The combination of toxin and antitoxin would seem to represent not a true chemical reaction but the adsorption of one colloid by another.

  17. Mojave Toxin: A Selective Ca(++) Channel Antagonist

    DTIC Science & Technology

    1988-07-01

    other than maitotoxin, blocking 3H-nitrendipine binding to the high affinity dihydropyridine receptor associated with the Ca++ channel, as well as... dihydropyridine receptors in rat synaptic membranes suggests that this toxin may be a useful proble of the Ca++ channel complex. It is not certain whether MoTX has...increase in intracellular Ca++ resulting from the binding of the toxin to dihydropyridine receptors coupled to Ca++ channels. The resolution of this

  18. Toxin-Antitoxin Systems of Staphylococcus aureus

    PubMed Central

    Schuster, Christopher F.; Bertram, Ralph

    2016-01-01

    Toxin-antitoxin (TA) systems are small genetic elements found in the majority of prokaryotes. They encode toxin proteins that interfere with vital cellular functions and are counteracted by antitoxins. Dependent on the chemical nature of the antitoxins (protein or RNA) and how they control the activity of the toxin, TA systems are currently divided into six different types. Genes comprising the TA types I, II and III have been identified in Staphylococcus aureus. MazF, the toxin of the mazEF locus is a sequence-specific RNase that cleaves a number of transcripts, including those encoding pathogenicity factors. Two yefM-yoeB paralogs represent two independent, but auto-regulated TA systems that give rise to ribosome-dependent RNases. In addition, omega/epsilon/zeta constitutes a tripartite TA system that supposedly plays a role in the stabilization of resistance factors. The SprA1/SprA1AS and SprF1/SprG1 systems are post-transcriptionally regulated by RNA antitoxins and encode small membrane damaging proteins. TA systems controlled by interaction between toxin protein and antitoxin RNA have been identified in S. aureus in silico, but not yet experimentally proven. A closer inspection of possible links between TA systems and S. aureus pathophysiology will reveal, if these genetic loci may represent druggable targets. The modification of a staphylococcal TA toxin to a cyclopeptide antibiotic highlights the potential of TA systems as rather untapped sources of drug discovery. PMID:27164142

  19. Toxin-Antitoxin Systems of Staphylococcus aureus.

    PubMed

    Schuster, Christopher F; Bertram, Ralph

    2016-05-05

    Toxin-antitoxin (TA) systems are small genetic elements found in the majority of prokaryotes. They encode toxin proteins that interfere with vital cellular functions and are counteracted by antitoxins. Dependent on the chemical nature of the antitoxins (protein or RNA) and how they control the activity of the toxin, TA systems are currently divided into six different types. Genes comprising the TA types I, II and III have been identified in Staphylococcus aureus. MazF, the toxin of the mazEF locus is a sequence-specific RNase that cleaves a number of transcripts, including those encoding pathogenicity factors. Two yefM-yoeB paralogs represent two independent, but auto-regulated TA systems that give rise to ribosome-dependent RNases. In addition, omega/epsilon/zeta constitutes a tripartite TA system that supposedly plays a role in the stabilization of resistance factors. The SprA1/SprA1AS and SprF1/SprG1 systems are post-transcriptionally regulated by RNA antitoxins and encode small membrane damaging proteins. TA systems controlled by interaction between toxin protein and antitoxin RNA have been identified in S. aureus in silico, but not yet experimentally proven. A closer inspection of possible links between TA systems and S. aureus pathophysiology will reveal, if these genetic loci may represent druggable targets. The modification of a staphylococcal TA toxin to a cyclopeptide antibiotic highlights the potential of TA systems as rather untapped sources of drug discovery.

  20. Sea Anemone Toxins Affecting Potassium Channels

    NASA Astrophysics Data System (ADS)

    Diochot, Sylvie; Lazdunski, Michel

    The great diversity of K+ channels and their wide distribution in many tissues are associated with important functions in cardiac and neuronal excitability that are now better understood thanks to the discovery of animal toxins. During the past few decades, sea anemones have provided a variety of toxins acting on voltage-sensitive sodium and, more recently, potassium channels. Currently there are three major structural groups of sea anemone K+ channel (SAK) toxins that have been characterized. Radioligand binding and electrophysiological experiments revealed that each group contains peptides displaying selective activities for different subfamilies of K+ channels. Short (35-37 amino acids) peptides in the group I display pore blocking effects on Kv1 channels. Molecular interactions of SAK-I toxins, important for activity and binding on Kv1 channels, implicate a spot of three conserved amino acid residues (Ser, Lys, Tyr) surrounded by other less conserved residues. Long (58-59 amino acids) SAK-II peptides display both enzymatic and K+ channel inhibitory activities. Medium size (42-43 amino acid) SAK-III peptides are gating modifiers which interact either with cardiac HERG or Kv3 channels by altering their voltage-dependent properties. SAK-III toxins bind to the S3C region in the outer vestibule of Kv channels. Sea anemones have proven to be a rich source of pharmacological tools, and some of the SAK toxins are now useful drugs for the diagnosis and treatment of autoimmune diseases.

  1. [Botulinum toxin therapy for spasticity].

    PubMed

    Masakado, Yoshihisa

    2014-09-01

    Botulinum toxin (BTX) administered as an adjunct to other interventions for spasticity can act as a useful and effective therapeutic tool for treating patients disabled by spasticity. Presence of other non-reflex motor disorders (muscle stiffness, shortness, and contracture) can complicate the clinical course and disturb rehabilitative process of patients with spasticity. Treatment of spasticity using BTX can improve paralysis by correcting muscular imbalance that follows these diseases. In patients with chronic severe spasticity, we also have to address unique and difficult-to-treat clinical conditions such as abnormal posture and movement disorders. The effectiveness of BTX in treating some of these conditions is discussed. Because patients with neurological disabilities can show complex dysfunctions, specific functional limitations, goals, and expected outcomes of treatment should be evaluated and discussed with the patient, family members, and caregivers, prior to initiating BTX therapy. BTX therapy might improve not only care, passive function, but also motor functions in these patients by supplementing intensive rehabilitation with repetitive transcranial magnetic stimulation, transcranial direct-current stimulation, peripheral electrical stimulation, muscle stretching, and other rehabilitation strategies.

  2. Botulinum toxin: mechanisms of action.

    PubMed

    Dressler, Dirk; Adib Saberi, Fereshte

    2005-01-01

    Botulinum toxin (BT) has been perceived as a lethal threat for many centuries. In the early 1980s, this perception completely changed when BT's therapeutic potential suddenly became apparent. We wish to give an overview over BT's mechanisms of action relevant for understanding its therapeutic use. BT's molecular mode of action includes extracellular binding to glycoprotein structures on cholinergic nerve terminals and intracellular blockade of the acetylcholine secretion. BT affects the spinal stretch reflex by blockade of intrafusal muscle fibres with consecutive reduction of Ia/II afferent signals and muscle tone without affecting muscle strength (reflex inhibition). This mechanism allows for antidystonic effects not only caused by target muscle paresis. BT also blocks efferent autonomic fibres to smooth muscles and to exocrine glands. Direct central nervous system effects are not observed, since BT does not cross the blood-brain barrier and since it is inactivated during its retrograde axonal transport. Indirect central nervous system effects include reflex inhibition, normalisation of reciprocal inhibition, intracortical inhibition and somatosensory evoked potentials. Reduction of formalin-induced pain suggests direct analgesic BT effects possibly mediated by blockade of substance P, glutamate and calcitonin gene-related peptide.

  3. A biomimetic nanosponge that absorbs pore-forming toxins.

    PubMed

    Hu, Che-Ming J; Fang, Ronnie H; Copp, Jonathan; Luk, Brian T; Zhang, Liangfang

    2013-05-01

    Detoxification treatments such as toxin-targeted anti-virulence therapy offer ways to cleanse the body of virulence factors that are caused by bacterial infections, venomous injuries and biological weaponry. Because existing detoxification platforms such as antisera, monoclonal antibodies, small-molecule inhibitors and molecularly imprinted polymers act by targeting the molecular structures of toxins, customized treatments are required for different diseases. Here, we show a biomimetic toxin nanosponge that functions as a toxin decoy in vivo. The nanosponge, which consists of a polymeric nanoparticle core surrounded by red blood cell membranes, absorbs membrane-damaging toxins and diverts them away from their cellular targets. In a mouse model, the nanosponges markedly reduce the toxicity of staphylococcal alpha-haemolysin (α-toxin) and thus improve the survival rate of toxin-challenged mice. This biologically inspired toxin nanosponge presents a detoxification treatment that can potentially treat a variety of injuries and diseases caused by pore-forming toxins.

  4. A biomimetic nanosponge that absorbs pore-forming toxins

    NASA Astrophysics Data System (ADS)

    Hu, Che-Ming J.; Fang, Ronnie H.; Copp, Jonathan; Luk, Brian T.; Zhang, Liangfang

    2013-05-01

    Detoxification treatments such as toxin-targeted anti-virulence therapy offer ways to cleanse the body of virulence factors that are caused by bacterial infections, venomous injuries and biological weaponry. Because existing detoxification platforms such as antisera, monoclonal antibodies, small-molecule inhibitors and molecularly imprinted polymers act by targeting the molecular structures of toxins, customized treatments are required for different diseases. Here, we show a biomimetic toxin nanosponge that functions as a toxin decoy in vivo. The nanosponge, which consists of a polymeric nanoparticle core surrounded by red blood cell membranes, absorbs membrane-damaging toxins and diverts them away from their cellular targets. In a mouse model, the nanosponges markedly reduce the toxicity of staphylococcal alpha-haemolysin (α-toxin) and thus improve the survival rate of toxin-challenged mice. This biologically inspired toxin nanosponge presents a detoxification treatment that can potentially treat a variety of injuries and diseases caused by pore-forming toxins.

  5. Simultaneous modifications of sodium channel gating by two scorpion toxins.

    PubMed Central

    Wang, G K; Strichartz, G

    1982-01-01

    The effects of purified scorpion toxins from two different species on the kinetics of sodium currents were evaluated in amphibian myelinated nerves under voltage clamp. A toxin from Leiurus quinquestriatus slowed and prevented sodium channel inactivation, exclusively, and a toxin from Centruroides sculpturatus Ewing reduced transient sodium currents during a maintained depolarization, and induced a novel inward current that appeared following repolarization, as previously reported by Cahalan (1975, J. Physiol. [Lond.]. 244:511-534) for the crude scorpion venom. Both of these effects were observed in fibers treated with both of these toxins, and the kinetics of the induced current were modified in a way that showed that the same sodium channels were modified simultaneously by both toxins. Although the toxins can act on different sites, the time course of the action of C. sculpturatus toxin was accelerated in the presence of the L. quinquestriatus toxin, indicating some form of interaction between the two toxin binding sites. PMID:6293596

  6. Selective brain uptake and behavioral effects of the cyanobacterial toxin BMAA (beta-N-methylamino-L-alanine) following neonatal administration to rodents.

    PubMed

    Karlsson, Oskar; Lindquist, Nils Gunnar; Brittebo, Eva B; Roman, Erika

    2009-06-01

    Cyanobacteria are extensively distributed in terrestrial and aquatic environments all over the world. Most cyanobacteria can produce the neurotoxin beta-N-methylamino-L-alanine (BMAA), which has been detected in several water systems and could accumulate in food chains. The aim of the study was to investigate the transfer of BMAA to fetal and neonatal brains and the effects of BMAA on the development of behavioral characteristics during the brain growth spurt (BGS) in rodents. Pregnant and neonatal mice were given an injection of (3)H-BMAA on gestational day 14 and postnatal day (PND) 10, respectively, and processed for tape-section autoradiography. The study revealed transplacental transfer of (3)H-BMAA and a significant uptake in fetal mouse brain. The radioactivity was specifically located in the hippocampus, striatum, brainstem, spinal cord and cerebellum of 10-day-old mice. The effect of repeated BMAA treatment (200 or 600 mg/kg s.c.) during BGS on rat behavior was also studied. BMAA treatment on PND 9-10 induced acute alterations, such as impaired locomotor ability and hyperactivity, in the behavior of neonatal rats. Furthermore, rats given the high dose of BMAA failed to habituate to the test environment when tested at juvenile age. In conclusion, the results demonstrated that BMAA was transferred to the neonatal brain and induced significant changes in the behavior of neonatal rats following administration during BGS. The observed behavioral changes suggest possible cognitive impairment. Increased information on the long-term effects of BMAA on cognitive function following fetal and neonatal exposure is required for assessment of the risk to children's health.

  7. Liquid chromatographic determination of the cyanobacterial toxin beta-n-methylamino-L-alanine in algae food supplements, freshwater fish, and bottled water.

    PubMed

    Scott, Peter M; Niedzwiadek, Barbara; Rawn, Dorothea F K; Lau, Ben P-Y

    2009-08-01

    Beta-N-Methylamino-L-alanine (BMAA) is a neurotoxin originally found in cycad seeds and now known to be produced by many species of freshwater and marine cyanobacteria. We developed a method for its determination in blue-green algae (BGA) food supplements, freshwater fish, and bottled water by using a strong cation-exchange, solid-phase extraction column for cleanup after 0.3 M trichloroacetic acid extraction of BGA supplements and fish. Bottled water was applied directly onto the solid-phase extraction column. For analysis of carbonated water, sonication and pH adjustment to 1.5 were needed. To determine protein-bound BMAA, the protein pellet left after extraction of the BGA supplement and fish was hydrolyzed by boiling with 6 M hydrochloric acid; BMAA was cleaned up on a C18 column and a strong cation-exchange, solid-phase extraction column. Determination of BMAA was by liquid chromatography of the fluorescent derivative formed with 9-fluorenylmethyl chloroformate. The method was validated by recovery experiments using spiking levels of 1.0 to 10 microg/g for BGA supplements, 0.5 to 5.0 microg/g for fish, and 0.002 microg/g for bottled water; mean recoveries were in the range of 67 to 89% for BGA supplements and fish, and 59 to 92% for bottled water. Recoveries of BMAA from spiked extracts of hydrolyzed protein from BGA supplements and fish ranged from 66 to 83%. The cleanup developed provides a useful method for surveying foods and supplements for BMAA and protein-bound BMAA.

  8. Clostridium perfringens Delta-Toxin Induces Rapid Cell Necrosis

    PubMed Central

    Seike, Soshi; Miyamoto, Kazuaki; Kobayashi, Keiko; Takehara, Masaya; Nagahama, Masahiro

    2016-01-01

    Clostridium perfringens delta-toxin is a β-pore-forming toxin and a putative pathogenic agent of C. perfringens types B and C. However, the mechanism of cytotoxicity of delta-toxin remains unclear. Here, we investigated the mechanisms of cell death induced by delta-toxin in five cell lines (A549, A431, MDCK, Vero, and Caco-2). All cell lines were susceptible to delta-toxin. The toxin caused rapid ATP depletion and swelling of the cells. Delta-toxin bound and formed oligomers predominantly in plasma membrane lipid rafts. Destruction of the lipid rafts with methyl β-cyclodextrin inhibited delta-toxin-induced cytotoxicity and ATP depletion. Delta-toxin caused the release of carboxyfluorescein from sphingomyelin-cholesterol liposomes and formed oligomers; toxin binding to the liposomes declined with decreasing cholesterol content in the liposomes. Flow cytometric assays with annexin V and propidium iodide revealed that delta-toxin treatment induced an elevation in the population of annexin V-negative and propidium iodide-positive cells. Delta-toxin did not cause the fragmentation of DNA or caspase-3 activation. Furthermore, delta-toxin caused damage to mitochondrial membrane permeability and cytochrome c release. In the present study, we demonstrate that delta-toxin produces cytotoxic activity through necrosis. PMID:26807591

  9. Exposure to anthrax toxin alters human leucocyte expression of anthrax toxin receptor 1.

    PubMed

    Ingram, R J; Harris, A; Ascough, S; Metan, G; Doganay, M; Ballie, L; Williamson, E D; Dyson, H; Robinson, J H; Sriskandan, S; Altmann, D M

    2013-07-01

    Anthrax is a toxin-mediated disease, the lethal effects of which are initiated by the binding of protective antigen (PA) with one of three reported cell surface toxin receptors (ANTXR). Receptor binding has been shown to influence host susceptibility to the toxins. Despite this crucial role for ANTXR in the outcome of disease, and the reported immunomodulatory consequence of the anthrax toxins during infection, little is known about ANTXR expression on human leucocytes. We characterized the expression levels of ANTXR1 (TEM8) on human leucocytes using flow cytometry. In order to assess the effect of prior toxin exposure on ANTXR1 expression levels, leucocytes from individuals with no known exposure, those exposed to toxin through vaccination and convalescent individuals were analysed. Donors could be defined as either 'low' or 'high' expressers based on the percentage of ANTXR1-positive monocytes detected. Previous exposure to toxins appears to modulate ANTXR1 expression, exposure through active infection being associated with lower receptor expression. A significant correlation between low receptor expression and high anthrax toxin-specific interferon (IFN)-γ responses was observed in previously infected individuals. We propose that there is an attenuation of ANTXR1 expression post-infection which may be a protective mechanism that has evolved to prevent reinfection.

  10. Purification of the Clostridium spiroforme binary toxin and activity of the toxin on HEp-2 cells.

    PubMed Central

    Popoff, M R; Milward, F W; Bancillon, B; Boquet, P

    1989-01-01

    The two components Sa (Mr, 44,000) and Sb (Mr, 92,000) of Clostridium spiroforme toxin were identified and characterized. Serological data permitted the identification of two groups of actin ADP-ribosylating clostridial toxins. The first consists of only C. botulinum C2. The second group includes spiroforme toxin, iota toxin of C. perfringens E, and an enzyme called CDT found in one strain of C. difficile, antibodies against which cross-react with all of the members of both groups. C. spiroforme toxin acted on cells by disrupting microfilaments by ADP-ribosylation of G actin. Toxicity was not blocked by 10 or 20 mM ammonium chloride and was only moderately inhibited by 30 mM NH4Cl. Inhibition of coated-pit formation in HEp-2 cells by potassium depletion strongly protected against the effect of C. spiroforme toxin. Toxicity was not blocked by incubation of HEp-2 cells and spiroforme toxin at 15 degrees C. These results suggest that this new binary toxin enters cells via the coated-pit-coated-vesicle pathway and might reach the cytoplasm at the same time as or before transfer to early endosomes. Images PMID:2545625

  11. Metabolism of HT-2 Toxin and T-2 Toxin in Oats

    PubMed Central

    Meng-Reiterer, Jacqueline; Bueschl, Christoph; Rechthaler, Justyna; Berthiller, Franz; Lemmens, Marc; Schuhmacher, Rainer

    2016-01-01

    The Fusarium mycotoxins HT-2 toxin (HT2) and T-2 toxin (T2) are frequent contaminants in oats. These toxins, but also their plant metabolites, may contribute to toxicological effects. This work describes the use of 13C-assisted liquid chromatography–high-resolution mass spectrometry for the first comprehensive study on the biotransformation of HT2 and T2 in oats. Using this approach, 16 HT2 and 17 T2 metabolites were annotated including novel glycosylated and hydroxylated forms of the toxins, hydrolysis products, and conjugates with acetic acid, putative malic acid, malonic acid, and ferulic acid. Further targeted quantitative analysis was performed to study toxin metabolism over time, as well as toxin and conjugate mobility within non-treated plant tissues. As a result, HT2-3-O-β-d-glucoside was identified as the major detoxification product of both parent toxins, which was rapidly formed (to an extent of 74% in HT2-treated and 48% in T2-treated oats within one day after treatment) and further metabolised. Mobility of the parent toxins appeared to be negligible, while HT2-3-O-β-d-glucoside was partly transported (up to approximately 4%) through panicle side branches and stem. Our findings demonstrate that the presented combination of untargeted and targeted analysis is well suited for the comprehensive elucidation of mycotoxin metabolism in plants. PMID:27929394

  12. Exposure of Lycopersicon esculentum to microcystin-LR: effects in the leaf proteome and toxin translocation from water to leaves and fruits.

    PubMed

    Gutiérrez-Praena, Daniel; Campos, Alexandre; Azevedo, Joana; Neves, Joana; Freitas, Marisa; Guzmán-Guillén, Remédios; Cameán, Ana María; Renaut, Jenny; Vasconcelos, Vitor

    2014-06-11

    Natural toxins such as those produced by freshwater cyanobacteria have been regarded as an emergent environmental threat. However, the impact of these water contaminants in agriculture is not yet fully understood. The aim of this work was to investigate microcystin-LR (MC-LR) toxicity in Lycopersicon esculentum and the toxin accumulation in this horticultural crop. Adult plants (2 month-old) grown in a greenhouse environment were exposed for 2 weeks to either pure MC-LR (100 μg/L) or Microcystis aeruginosa crude extracts containing 100 μg/L MC-LR. Chlorophyll fluorescence was measured, leaf proteome investigated with two-dimensional gel electrophoresis and Matrix Assisted Laser Desorption Ionization Time-of-Flight (MALDI-TOF)/TOF, and toxin bioaccumulation assessed by liquid chromatography-mass spectrometry (LC-MS)/MS. Variations in several protein markers (ATP synthase subunits, Cytochrome b6-f complex iron-sulfur, oxygen-evolving enhancer proteins) highlight the decrease of the capacity of plants to synthesize ATP and to perform photosynthesis, whereas variations in other proteins (ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit and ribose-5-phosphate isomerase) suggest an increase of carbon fixation and decrease of carbohydrate metabolism reactions in plants exposed to pure MC-LR and cyanobacterial extracts, respectively. MC-LR was found in roots (1635.21 μg/kg fw), green tomatoes (5.15-5.41 μg/kg fw), mature tomatoes (10.52-10.83 μg/kg fw), and leaves (12,298.18 μg/kg fw). The results raise concerns relative to food safety and point to the necessity of monitoring the bioaccumulation of water toxins in agricultural systems affected by cyanotoxin contamination.

  13. Exposure of Lycopersicon Esculentum to Microcystin-LR: Effects in the Leaf Proteome and Toxin Translocation from Water to Leaves and Fruits

    PubMed Central

    Gutiérrez-Praena, Daniel; Campos, Alexandre; Azevedo, Joana; Neves, Joana; Freitas, Marisa; Guzmán-Guillén, Remédios; Cameán, Ana María; Renaut, Jenny; Vasconcelos, Vitor

    2014-01-01

    Natural toxins such as those produced by freshwater cyanobacteria have been regarded as an emergent environmental threat. However, the impact of these water contaminants in agriculture is not yet fully understood. The aim of this work was to investigate microcystin-LR (MC-LR) toxicity in Lycopersicon esculentum and the toxin accumulation in this horticultural crop. Adult plants (2 month-old) grown in a greenhouse environment were exposed for 2 weeks to either pure MC-LR (100 μg/L) or Microcystis aeruginosa crude extracts containing 100 μg/L MC-LR. Chlorophyll fluorescence was measured, leaf proteome investigated with two-dimensional gel electrophoresis and Matrix Assisted Laser Desorption Ionization Time-of-Flight (MALDI-TOF)/TOF, and toxin bioaccumulation assessed by liquid chromatography-mass spectrometry (LC-MS)/MS. Variations in several protein markers (ATP synthase subunits, Cytochrome b6-f complex iron-sulfur, oxygen-evolving enhancer proteins) highlight the decrease of the capacity of plants to synthesize ATP and to perform photosynthesis, whereas variations in other proteins (ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit and ribose-5-phosphate isomerase) suggest an increase of carbon fixation and decrease of carbohydrate metabolism reactions in plants exposed to pure MC-LR and cyanobacterial extracts, respectively. MC-LR was found in roots (1635.21 μg/kg fw), green tomatoes (5.15–5.41 μg/kg fw), mature tomatoes (10.52–10.83 μg/kg fw), and leaves (12,298.18 μg/kg fw). The results raise concerns relative to food safety and point to the necessity of monitoring the bioaccumulation of water toxins in agricultural systems affected by cyanotoxin contamination. PMID:24921194

  14. Synthesis and Biology of Cyclic Imine Toxins, An Emerging Class of Potent, Globally Distributed Marine Toxins

    PubMed Central

    Stivala, Craig E.; Benoit, Evelyne; Araoz, Romulo; Servent, Denis; Novikov, Alexei

    2014-01-01

    From a small group of exotic compounds isolated only two decades ago, Cyclic Imine (CI) toxins have become a major class of marine toxins with global distribution. Their distinct chemical structure, biological mechanism of action, and intricate chemistry ensures that CI toxins will continue to be the subject of fascinating fundamental studies in the broad fields of chemistry, chemical biology, and toxicology. The worldwide occurrence of potent CI toxins in marine environments, their accumulation in shellfish, and chemical stability are important considerations in assessing risk factors for human health. This review article aims to provide an account of chemistry, biology, and toxicology of CI toxins from their discovery to the present day. PMID:25338021

  15. Efficient recovery of nitrate and phosphate from wastewater by an amine-grafted adsorbent for cyanobacterial biomass production.

    PubMed

    Kim, Jungmin; Hwang, Min-Jin; Lee, Sang-Jun; Noh, Won; Kwon, Jung Min; Choi, Jin Soo; Kang, Chang-Min

    2016-04-01

    Various types of wastewater have been widely utilized in microalgae and cyanobacteria cultivation for environmental and economic reasons. However, the problems of low cell growth and biomass contamination due to direct use of wastewater remain unresolved. In the present study, nitrate and phosphate were separated from wastewater by adsorption and subsequently used for cyanobacterial biomass production. To this end, an amine-grafted magnetic absorbent was synthesized. The synthesized absorbent recovered ca. 78% nitrate and 93% phosphate from wastewater. Regenerated medium was prepared using recovered nutrients as nitrogen and phosphate sources, which were efficiently assimilated by cyanobacterial culture. Compared to synthetic medium, there was no difference in growth and nutrient removal using regenerated medium. The proposed indirect method of wastewater utilization would prevent contamination of the produced biomass by unfavorable substances, which will broaden its potential applications.

  16. Expression of a cyanobacterial {del}{sup 6}-desaturase gene results in {gamma}-linolenic acid production in transgenic plants

    SciTech Connect

    Reddy, A.S.; Thomas, T.L.

    1996-05-01

    Gam