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1
Vilar, Mauro C. P., Thiago F. C. P. Rodrigues, Luan O. Silva, Ana Beatriz F. Pacheco, Aloysio S. Ferrão-Filho et Sandra M. F. O. Azevedo. « Ecophysiological Aspects and sxt Genes Expression Underlying Induced Chemical Defense in STX-Producing Raphidiopsis raciborskii (Cyanobacteria) against the Zooplankter Daphnia gessneri ». Toxins 13, no 6 (8 juin 2021) : 406. http://dx.doi.org/10.3390/toxins13060406.
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Cyanobacteria stand out among phytoplankton when they form massive blooms and produce toxins. Because cyanotoxin genes date to the origin of metazoans, the hypothesis that cyanotoxins function as a defense against herbivory is still debated. Although their primary cellular function might vary, these metabolites could have evolved as an anti-predator response. Here we evaluated the physiological and molecular responses of a saxitoxin-producing Raphidiopsis raciborskii to infochemicals released by the grazer Daphnia gessneri. Induced chemical defenses were evidenced in R. raciborskii as a significant increase in the transcription level of sxt genes, followed by an increase in saxitoxin content when exposed to predator cues. Moreover, cyanobacterial growth decreased, and no significant effects on photosynthesis or morphology were observed. Overall, the induced defense response was accompanied by a trade-off between toxin production and growth. These results shed light on the mechanisms underlying zooplankton–cyanobacteria interactions in aquatic food webs. The widespread occurrence of the cyanobacterium R. raciborskii in freshwater bodies has been attributed to its phenotypic plasticity. Assessing the potential of this species to thrive over interaction filters such as zooplankton grazing pressure can enhance our understanding of its adaptive success.
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Mucci, Maíra, Iame A. Guedes, Elisabeth J. Faassen et Miquel Lürling. « Chitosan as a Coagulant to Remove Cyanobacteria Can Cause Microcystin Release ». Toxins 12, no 11 (10 novembre 2020) : 711. http://dx.doi.org/10.3390/toxins12110711.
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Chitosan has been tested as a coagulant to remove cyanobacterial nuisance. While its coagulation efficiency is well studied, little is known about its effect on the viability of the cyanobacterial cells. This study aimed to test eight strains of the most frequent bloom-forming cyanobacterium, Microcystis aeruginosa, exposed to a realistic concentration range of chitosan used in lake restoration management (0 to 8 mg chitosan L−1). We found that after 1 h of contact with chitosan, in seven of the eight strains tested, photosystem II efficiency was decreased, and after 24 h, all the strains tested were affected. EC50 values varied from 0.47 to > 8 mg chitosan L-1 between the strains, which might be related to the amount of extracellular polymeric substances. Nucleic acid staining (Sytox-Green®) illustrated the loss of membrane integrity in all the strains tested, and subsequent leakage of pigments was observed, as well as the release of intracellular microcystin. Our results indicate that strain variability hampers generalization about species response to chitosan exposure. Hence, when used as a coagulant to manage cyanobacterial nuisance, chitosan should be first tested on the natural site-specific biota on cyanobacteria removal efficiency, as well as on cell integrity aspects.
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Śliwińska-Wilczewska, Sylwia, Aldo Barreiro Felpeto, Katarzyna Możdżeń, Vitor Vasconcelos et Adam Latała. « Physiological Effects on Coexisting Microalgae of the Allelochemicals Produced by the Bloom-Forming Cyanobacteria Synechococcus sp. and Nodularia Spumigena ». Toxins 11, no 12 (6 décembre 2019) : 712. http://dx.doi.org/10.3390/toxins11120712.
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Only a few studies have documented the physiological effects of allelopathy from cyanobacteria against coexisting microalgae. We investigated the allelopathic ability of the bloom-forming cyanobacteria Synechococcus sp. and Nodularia spumigena filtrates on several aspects related to the physiology of the target species: population growth, cell morphology, and several indexes of photosynthesis rate and respiration. The target species were the following: two species of green algae (Oocystis submarina, Chlorella vulgaris) and two species of diatoms (Bacillaria paxillifer, Skeletonema marinoi). These four species coexist in the natural environment with the employed strains of Synechococcus sp. and N. spumigena employed. The tests were performed with single and repeated addition of cyanobacterial cell-free filtrate. We also tested the importance of the growth phase in the strength of the allelopathic effect. The negative effects of both cyanobacteria were the strongest with repeated exudates addition, and generally, Synechococcus sp. and N. spumigena were allelopathic only in the exponential growth phase. O. submarina was not negatively affected by Synechococcus filtrates in any of the parameters studied, while C. vulgaris, B. paxillifer, and S. marinoi were affected in several ways. N. spumigena was characterized by a stronger allelopathic activity than Synechococcus sp., showing a negative effect on all target species. The highest decline in growth, as well as the most apparent cell physical damage, was observed for the diatom S. marinoi. Our findings suggest that cyanobacterial allelochemicals are associated with the cell physical damage, as well as a reduced performance in respiration and photosynthesis system in the studied microalgae which cause the inhibition of the population growth. Moreover, our study has shown that some biotic factors that increase the intensity of allelopathic effects may also alter the ratio between bloom-forming cyanobacteria and some phytoplankton species that occur in the same aquatic ecosystem.
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Mallick, Ranjana. « Implication of blue green algae on yield attributes and economics of rice cultivation ». International Journal of Bioassays 6, no 06 (1 juin 2017) : 5386. http://dx.doi.org/10.21746/ijbio.2017.06.001.
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Indian agriculture is presently at cross roads as it has to increase output at one hand and has to take care of environmental aspects on the other hand. Rice cultivation is also facing the same dilemma. Use of blue green algae as bio fertilizer is one possible way to minimize application of synthetic fertilizers which have far reaching implications on environment and health. Present research study was formulated to screen most suitable combination of different species of cyanobacteria on yield attribute of Vandana variety of rice grown in Hazaribagh district. Three species of cyanobacteria, Anabaena + Nostoc + Gloeotrichia was studied and was compared with controlled condition and condition with conventional fertilization. It was observed that combination of biofertilizer gives better result on all parameters when compared to conventional fertilizer.
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dos Santos Costa, Rafaela, Gabrielle Rabelo Quadra, Helena de Oliveira Souza, Viviane Souza do Amaral et Julio Alejandro Navoni. « The link between pharmaceuticals and cyanobacteria : a review regarding ecotoxicological, ecological, and sanitary aspects ». Environmental Science and Pollution Research 28, no 31 (12 juin 2021) : 41638–50. http://dx.doi.org/10.1007/s11356-021-14698-5.
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Gӓrtner, Georg, Maya Stoyneva-Gӓrtner et Blagoy Uzunov. « Algal Toxic Compounds and Their Aeroterrestrial, Airborne and other Extremophilic Producers with Attention to Soil and Plant Contamination : A Review ». Toxins 13, no 5 (29 avril 2021) : 322. http://dx.doi.org/10.3390/toxins13050322.
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The review summarizes the available knowledge on toxins and their producers from rather disparate algal assemblages of aeroterrestrial, airborne and other versatile extreme environments (hot springs, deserts, ice, snow, caves, etc.) and on phycotoxins as contaminants of emergent concern in soil and plants. There is a growing body of evidence that algal toxins and their producers occur in all general types of extreme habitats, and cyanobacteria/cyanoprokaryotes dominate in most of them. Altogether, 55 toxigenic algal genera (47 cyanoprokaryotes) were enlisted, and our analysis showed that besides the “standard” toxins, routinely known from different waterbodies (microcystins, nodularins, anatoxins, saxitoxins, cylindrospermopsins, BMAA, etc.), they can produce some specific toxic compounds. Whether the toxic biomolecules are related with the harsh conditions on which algae have to thrive and what is their functional role may be answered by future studies. Therefore, we outline the gaps in knowledge and provide ideas for further research, considering, from one side, the health risk from phycotoxins on the background of the global warming and eutrophication and, from the other side, the current surge of interest which phycotoxins provoke due to their potential as novel compounds in medicine, pharmacy, cosmetics, bioremediation, agriculture and all aspects of biotechnological implications in human life.
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Shaw, G., et P. K. S. Lam. « Health aspects of freshwater cyanobacterial toxins ». Water Supply 7, no 2 (1 juillet 2007) : 193–203. http://dx.doi.org/10.2166/ws.2007.054.
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Cyanobacterial (blue-green algal) toxins are known to cause poisoning in humans, livestock and wild animals. Based on their toxic mechanisms, cyanobacterial toxins are generally categorized as neurotoxins, hepatotoxins or cytotoxins. The acute oral toxicities of these toxins vary substantially, with the saxitoxins being the most toxic having an LD50 of 60 μg/kg. By comparison, the acute oral LD50 for microcystin LR (the most toxic congener) and cylindrospermopsin are approximately 5,000 to 10,000 μg/kg and 6,000 μg/kg over 5 days, respectively. There are well known adverse health issues of cyanobacterial toxin poisonings. The most serious health consequences have occurred in Brazil with the reported deaths of people from gastrointestinal symptoms associated with exposure to microcystins and cylindrospermopsin. Increased number of symptoms has also been reported via exposure to cyanobacterial toxins through water-based recreational activities. Toxins may also be present in drinking water and thus guideline values are necessary to protect the health of the population. Guideline values are available for microcystins but not for saxitoxins, cylindrospermopsin or deoxycylindrospermopsin. Considerable research is being undertaken currently on more fully understanding the mechanisms of toxicity of cylindrospermopsin to enable relevant guidelines to be established.
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Pereira, Alessandro Rhadamek Alves, João Batista Lopes, Giovana Mira de Espindola et Carlos Ernando da Silva. « Retrieval and mapping of chlorophyll-a concentration from Sentinel-2 images in an urban river in the semiarid region of Brazil ». Ambiente e Agua - An Interdisciplinary Journal of Applied Science 15, no 2 (8 avril 2020) : 1. http://dx.doi.org/10.4136/ambi-agua.2488.
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Recently, the Poti river mouth region has experienced environmental impacts that resulted in a change of landscape in its dry season, highlighting the eutrophication and proliferation of phytoplankton, algae, cyanobacteria and aquatic plants. Considering the aspects related to water-quality monitoring in the semiarid region of Brazil from remote sensing, this study aimed to evaluate the performance of Sentinel-2A satellite data in the retrieval of chlorophyll-a concentration in Poti River in Teresina, Piaui, Brazil. The chlorophyll-a concentration retrieval and mapping methodology involved the study of the water surface reflectance in Sentinel-2A images and their correlation with the chlorophyll-a data collected in situ during the years 2016 and 2017. The results generated by the Chl-1, Ha et al. (2017), Chl-2, Page et al. (2018), and Chl-3, Kuhn et al. (2019) equations show the need for calibrating the algorithms used for the Poti River water components. However, the empirical algorithm Chl-2 shows a correlation has been established to identify the spatiotemporal variation of chlorophyll-a concentration along the Poti River broadly and not punctually. The spatial distribution of this pigment in maps derived from Sentinel-2A is consistent with the pattern of occurrence determined by the in situ data. Therefore, the MSI sensor proved to be a tool suitable for the retrieval and monitoring of chlorophyll-a concentration along the Poti River.
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Cunha, Isabel, Rita Biltes, MGF Sales et Vitor Vasconcelos. « Aptamer-Based Biosensors to Detect Aquatic Phycotoxins and Cyanotoxins ». Sensors 18, no 7 (20 juillet 2018) : 2367. http://dx.doi.org/10.3390/s18072367.
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Aptasensors have a great potential for environmental monitoring, particularly for real-time on-site detection of aquatic toxins produced by marine and freshwater microorganisms (cyanobacteria, dinoflagellates, and diatoms), with several advantages over other biosensors that are worth considering. Freshwater monitoring is of vital importance for public health, in numerous human activities, and animal welfare, since these toxins may cause fatal intoxications. Similarly, in marine waters, very effective monitoring programs have been put in place in many countries to detect when toxins exceed established regulatory levels and accordingly enforce shellfish harvesting closures. Recent advances in the fields of aptamer selection, nanomaterials and communication technologies, offer a vast array of possibilities to develop new imaginative strategies to create improved, ultrasensitive, reliable and real-time devices, featuring unique characteristics to produce and amplify the signal. So far, not many strategies have been used to detect aquatic toxins, mostly limited to the optic and electrochemical sensors, the majority applied to detect microcystin-LR using a target-induced switching mode. The limits of detection of these aptasensors have been decreasing from the nM to the fM order of magnitude in the past 20 years. Aspects related to sensor components, performance, aptamers sequences, matrices analyzed and future perspectives, are considered and discussed.
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Tazart, Zakaria, Maura Manganelli, Simona Scardala, Franca Maria Buratti, Federica Nigro Di Gregorio, Mountasser Douma, Khadija Mouhri, Emanuela Testai et Mohammed Loudiki. « Remediation Strategies to Control Toxic Cyanobacterial Blooms : Effects of Macrophyte Aqueous Extracts on Microcystis aeruginosa (Growth, Toxin Production and Oxidative Stress Response) and on Bacterial Ectoenzymatic Activities ». Microorganisms 9, no 8 (23 août 2021) : 1782. http://dx.doi.org/10.3390/microorganisms9081782.
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Increasing toxic cyanobacterial blooms in freshwater demand environmentally friendly solutions to control their growth and toxicity, especially in arid countries, where most drinking water is produced from surface reservoirs. We tested the effects of macrophyte allelochemicals on Microcystis aeruginosa and on the fundamental role of bacteria in nutrient recycling. The effects of Ranunculus aquatilis aqueous extract, the most bioactive of four Moroccan macrophyte extracts, were tested in batch systems on M. aeruginosa growth, toxin production and oxidative stress response and on the ectoenzymatic activity associated with the bacterial community. M. aeruginosa density was reduced by 82.18%, and a significant increase in oxidative stress markers was evidenced in cyanobacterial cells. Microcystin concentration significantly decreased, and they were detected only intracellularly, an important aspect in managing toxic blooms. R. aquatilis extract had no negative effects on associated bacteria. These results confirm a promising use of macrophyte extracts, but they cannot be generalized. The use of the extract on other toxic strains, such as Planktothrix rubescens, Raphidiopsis raciborskii and Chrysosporum ovalisporum, caused a reduction in growth rate but not in cyanotoxin content, increasing toxicity. The need to assess species-specific cyanobacteria responses to verify the efficacy and safety of the extracts for human health and the environment is highlighted.
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Daus, Milan, Katharina Koberger, Nele Gnutzmann, Tobias Hertrich et Rüdiger Glaser. « Transferring Water While Transforming Landscape : New Societal Implications, Perceptions and Challenges of Management in the Reservoir System Franconian Lake District ». Water 11, no 12 (23 novembre 2019) : 2469. http://dx.doi.org/10.3390/w11122469.
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This study investigates the different stakeholder based discourses and challenges around the Franconian Lake District (FLD), a recently constructed large reservoir system in Germany. The construction and operation of reservoirs represent a massive alteration of their natural and social environments leading to discourses and potential conflicts between a wide scope of heterogeneous interest patterns. Studies have shown that large reservoirs can be an important contributor to water supply, irrigation, energy storage and therefore climate change mitigation on a global scale, which brings these conflicting interests to a broader societal concern. Yet, information about conflicts around existing (German) reservoirs is limited. To assess which issues and conflicts appear on the daily agenda and how they are perceived, communicated and addressed by the stakeholders, a total of 609 articles in the Nürnberger Nachrichten and 22 semi-structured expert interviews were analysed, using qualitative content analysis. The results show that discourses at FLD are predominantly determined by economic factors. Management issues are dominated by discussions about cyanobacteria, which can pose a health risk, thereby impeding recreational use of the lakes and consequently causing economic losses and an image problem for the region. The issue is also strongly interlinked with other aspects of concern and therefore one of the main challenges at the FLD. Due to the construction of the lakes and the evolving strong tourism sector, the formerly agricultural region was subject to a major structural change linking together a very heterogeneous set of interests. The results of this study can help in establishing a management framework to suit all stakeholders and possibly be transferrable to similar projects.
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Malviya, Deepti, Pramod Kumar Sahu, Udai B. Singh, Surinder Paul, Amrita Gupta, Abhay Raj Gupta, Shailendra Singh et al. « Lesson from Ecotoxicity : Revisiting the Microbial Lipopeptides for the Management of Emerging Diseases for Crop Protection ». International Journal of Environmental Research and Public Health 17, no 4 (23 février 2020) : 1434. http://dx.doi.org/10.3390/ijerph17041434.
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Microorganisms area treasure in terms of theproduction of various bioactive compounds which are being explored in different arenas of applied sciences. In agriculture, microbes and their bioactive compounds are being utilized in growth promotion and health promotion withnutrient fortification and its acquisition. Exhaustive explorations are unraveling the vast diversity of microbialcompounds with their potential usage in solving multiferous problems incrop production. Lipopeptides are one of such microbial compounds which havestrong antimicrobial properties against different plant pathogens. These compounds are reported to be produced by bacteria, cyanobacteria, fungi, and few other microorganisms; however, genus Bacillus alone produces a majority of diverse lipopeptides. Lipopeptides are low molecular weight compounds which havemultiple industrial roles apart from being usedas biosurfactants and antimicrobials. In plant protection, lipopeptides have wide prospects owing totheirpore-forming ability in pathogens, siderophore activity, biofilm inhibition, and dislodging activity, preventing colonization bypathogens, antiviral activity, etc. Microbes with lipopeptides that haveall these actions are good biocontrol agents. Exploring these antimicrobial compounds could widen the vistasof biological pest control for existing and emerging plant pathogens. The broader diversity and strong antimicrobial behavior of lipopeptides could be a boon for dealing withcomplex pathosystems and controlling diseases of greater economic importance. Understanding which and how these compounds modulate the synthesis and production of defense-related biomolecules in the plants is a key question—the answer of whichneeds in-depth investigation. The present reviewprovides a comprehensive picture of important lipopeptides produced by plant microbiome, their isolation, characterization, mechanisms of disease control, behavior against phytopathogens to understand different aspects of antagonism, and potential prospects for future explorations as antimicrobial agents. Understanding and exploring the antimicrobial lipopeptides from bacteria and fungi could also open upan entire new arena of biopesticides for effective control of devastating plant diseases.
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Du, Xingde, Haohao Liu, Le Yuan, Yueqin Wang, Ya Ma, Rui Wang, Xinghai Chen, Michael Losiewicz, Hongxiang Guo et Huizhen Zhang. « The Diversity of Cyanobacterial Toxins on Structural Characterization, Distribution and Identification : A Systematic Review ». Toxins 11, no 9 (12 septembre 2019) : 530. http://dx.doi.org/10.3390/toxins11090530.
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The widespread distribution of cyanobacteria in the aquatic environment is increasing the risk of water pollution caused by cyanotoxins, which poses a serious threat to human health. However, the structural characterization, distribution and identification techniques of cyanotoxins have not been comprehensively reviewed in previous studies. This paper aims to elaborate the existing information systematically on the diversity of cyanotoxins to identify valuable research avenues. According to the chemical structure, cyanotoxins are mainly classified into cyclic peptides, alkaloids, lipopeptides, nonprotein amino acids and lipoglycans. In terms of global distribution, the amount of cyanotoxins are unbalanced in different areas. The diversity of cyanotoxins is more obviously found in many developed countries than that in undeveloped countries. Moreover, the threat of cyanotoxins has promoted the development of identification and detection technology. Many emerging methods have been developed to detect cyanotoxins in the environment. This communication provides a comprehensive review of the diversity of cyanotoxins, and the detection and identification technology was discussed. This detailed information will be a valuable resource for identifying the various types of cyanotoxins which threaten the environment of different areas. The ability to accurately identify specific cyanotoxins is an obvious and essential aspect of cyanobacterial research.
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Sotiroudis, Theodore, et Georgios Sotiroudis. « Health aspects of Spirulina (Arthrospira) microalga food supplement ». Journal of the Serbian Chemical Society 78, no 3 (2013) : 395–405. http://dx.doi.org/10.2298/jsc121020152s.
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Spirulina, now named Arthrospira, is a microscopic and filamentous cyanobacterium that has a long history of use as a safe food lacking toxicity. It is commercially produced in large outdoor ponds under controlled conditions. The aim of this review article is to summarize available recent information concerning human clinical potential and applications of Spirulina, as well as clinical data related to the safety and side effects of Spirulina. Potential health benefits of Spirulina are mainly due to its chemical composition, which includes proteins (the highest protein content of any natural food, 55%-70%), carbohydrates, essential amino acids, minerals (especially iron), essential fatty acids, vitamins, and pigments. In this respect, three major bioactive components of Spirulina, the protein phycocyanin (a biliprotein pigment), sulfated polysaccharides and gamma linolenic acid seem to play significant role in imparting improved human body functions. Furthermore, new experimental evidence supports the immunomodulation and antiviral effects of Spirulina supplementation. According to the Dietary Supplements Information Expert Committee of United States Pharmacopeial Convention the available clinical evidence does not indicate a serious risk to health or other public health concerns for Spirulina. However, a few cases of severe side-effects have been reported.
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Bereded, Negash Kabtimer, Getachew Beneberu Abebe, Solomon Workneh Fanta, Manuel Curto, Herwig Waidbacher, Harald Meimberg et Konrad J. Domig. « The Impact of Sampling Season and Catching Site (Wild and Aquaculture) on Gut Microbiota Composition and Diversity of Nile Tilapia (Oreochromis niloticus) ». Biology 10, no 3 (1 mars 2021) : 180. http://dx.doi.org/10.3390/biology10030180.
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The gut microbiota of fishes is known to play an essential role in diverse aspects of host biology. The gut microbiota of fish is affected by various environmental parameters, including temperature changes, salinity and diet. Studies of effect of environment on gut microbiota enables to have a further understanding of what comprises a healthy microbiota under different environmental conditions. However, there is insufficient understanding regarding the effects of sampling season and catching site (wild and aquaculture) on the gut microbiota of Nile tilapia. This study characterised gut microbial composition and diversity from samples collected from Lake Tana and the Bahir Dar aquaculture facility centre using 16S rDNA Illumina MiSeq platform sequencing. Firmicutes and Fusobacteria were the most dominant phyla in the Lake Tana samples, while Proteobacteria was the most dominant in the aquaculture samples. The results of differential abundance testing clearly indicated significant differences for Firmicutes, Fusobacteria, Bacteroidetes and Cyanobacteria across sampling months. However, Proteobacteria, Chloroflexi, Fusobacteria and Cyanobacteria were significantly enriched in the comparison of samples from the Lake Tana and aquaculture centre. Significant differences were observed in microbial diversity across sampling months and between wild and captive Nile tilapia. The alpha diversity clearly showed that samples from the aquaculture centre (captive) had a higher diversity than the wild Nile tilapia samples from Lake Tana. The core gut microbiota of all samples of Nile tilapia used in our study comprised Firmicutes, Proteobacteria and Fusobacteria. This study clearly showed the impact of sampling season and catching site (wild and aquaculture) on the diversity and composition of bacterial communities associated with the gut of Nile tilapia. Overall, this is the first study on the effects of sampling season and catching site on the gut microbiota of Nile tilapia in Ethiopia. Future work is recommended to precisely explain the causes of these changes using large representative samples of Nile tilapia from different lakes and aquaculture farms.
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Mazurkiewicz, Jakub, Agata Mazur, Robert Mazur, Krzysztof Chmielowski, Wojciech Czekała et Damian Janczak. « The Process of Microbiological Remediation of the Polluted Słoneczko Reservoir in Poland : For Reduction of Water Pollution and Nutrients Management ». Water 12, no 11 (26 octobre 2020) : 3002. http://dx.doi.org/10.3390/w12113002.
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The article discusses the impact of nutrients from sewage on the state of the sewage receiver. Bioremediation was carried out through the use of effective microorganisms. The potential recovery of valuable mineral and organic substances in the form of fertilizers was also examined. The Słoneczko Reservoir is a bathing area and serves many people in the summertime as a place of water recreation. Water quality deteriorated intensively from 2006 as a result of illegal wastewater discharge and the impact of fecal pollution from bathers. The high concentration of nutrients in the water was the cause of the eutrophication process and blooms of cyanobacteria, which pose a threat to human health in the bathing area. The bathing area was also closed many times by sanitary services as a result of exceeding the number of Escherichia coli and Enterococcus faecalis in the water. At the bottom of the reservoir, there was a layer of sediments with a thickness of 30–70 cm. Thus, the processes of anaerobic decomposition generated odor, causing nuisance in the reservoir area. Water transparency varied from 30 to 50 cm, due to the accumulation of suspensions and biomass of planktonic algae. The reservoir was subjected to microbiological bioremediation in 2017 and 2018 to polluted water treatment and to reduce the organic content of bottom sediments. Already after the first application of biopreparations putrefactive odors and the eutrophication process disappeared at the end of the 2017 summer season. Bioremediation reduced the value of E. coli and E. feacalis to the acceptable level. After the second application in 2018, the organic fraction of the bottom sediments was reduced to a very low level and the water transparency reached the bottom (maximum depth was 2.2 m) throughout the entire bathing area. The effect of the water remediation was maintained until 2019, and the surface water quality remained at a very good level. An important aspect in this case is also the exploitation of bottom sediments, because they are rich in nutrients and organic matter, and therefore it may have some potential as a fertilizer. The recovery of nutrients can be used in plant or pot production. However, they contain compounds that degrade quickly, causing unpleasant odors and threatening the environment. Thus, they should be managed and handled in an environmentally friendly and sustainable way.
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Adamski, Michał, Ewelina Chrapusta, Beata Bober, Ariel Kamiński et Jan Białczyk. « Cylindrospermopsin : cyanobacterial secondary metabolite. Biological aspects and potential risk for human health and life ». Oceanological and Hydrobiological Studies 43, no 4 (1 janvier 2014). http://dx.doi.org/10.2478/s13545-014-0148-5.
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AbstractCylindrospermopsin (CYN) is a cytotoxin produced by several species of cyanobacteria, which occur all over the world. It was demonstrated that CYN has a wide spectrum of biological activity in animal cells, involving hepatotoxicity, genotoxicity, cytotoxicity and carcinogenic potential, and is considered as one of the factors that caused human poisoning in Palm Island (Australia) and in Caruaru (Brazil). This compound may be introduced into organism by several ways, including consumption of water, fishes and seafood as well as accidental swallowing or aerosol spray inhalation during recreational using of reservoirs covered by cyanobacterial blooms. The information about the CYN impact on environment and its degradation processes under natural conditions is scant. Taking this into consideration CYN should be regarded as a potential threat to human health and life. This review presents physicochemical characteristic and biological activity of CYN, occurrence in freshwaters and its sensitivity to the influence of some environmental factors.
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Zeigler Allen, Lisa, John P. McCrow, Karolina Ininbergs, Christopher L. Dupont, Jonathan H. Badger, Jeffery M. Hoffman, Martin Ekman, Andrew E. Allen, Birgitta Bergman et J. Craig Venter. « The Baltic Sea Virome : Diversity and Transcriptional Activity of DNA and RNA Viruses ». mSystems 2, no 1 (14 février 2017). http://dx.doi.org/10.1128/msystems.00125-16.
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ABSTRACT Inferred virus-host relationships, community structures of ubiquitous ecologically relevant groups, and identification of transcriptionally active populations have been achieved with our Baltic Sea study. Further, these data, highlighting the transcriptional activity of viruses, represent one of the more powerful uses of omics concerning ecosystem health. The use of omics-related data to assess ecosystem health holds great promise for rapid and relatively inexpensive determination of perturbations and risk, explicitly with regard to viral assemblages, as no single marker gene is suitable for widespread taxonomic coverage. Metagenomic and metatranscriptomic data were generated from size-fractionated samples from 11 sites within the Baltic Sea and adjacent marine waters of Kattegat and freshwater Lake Torneträsk in order to investigate the diversity, distribution, and transcriptional activity of virioplankton. Such a transect, spanning a salinity gradient from freshwater to the open sea, facilitated a broad genome-enabled investigation of natural as well as impacted aspects of Baltic Sea viral communities. Taxonomic signatures representative of phages within the widely distributed order Caudovirales were identified with enrichments in lesser-known families such as Podoviridae and Siphoviridae. The distribution of phage reported to infect diverse and ubiquitous heterotrophic bacteria (SAR11 clades) and cyanobacteria (Synechococcus sp.) displayed population-level shifts in diversity. Samples from higher-salinity conditions (>14 practical salinity units [PSU]) had increased abundances of viruses for picoeukaryotes, i.e., Ostreococcus. These data, combined with host diversity estimates, suggest viral modulation of diversity on the whole-community scale, as well as in specific prokaryotic and eukaryotic lineages. RNA libraries revealed single-stranded DNA (ssDNA) and RNA viral populations throughout the Baltic Sea, with ssDNA phage highly represented in Lake Torneträsk. Further, our data suggest relatively high transcriptional activity of fish viruses within diverse families known to have broad host ranges, such as Nodoviridae (RNA), Iridoviridae (DNA), and predicted zoonotic viruses that can cause ecological and economic damage as well as impact human health. IMPORTANCE Inferred virus-host relationships, community structures of ubiquitous ecologically relevant groups, and identification of transcriptionally active populations have been achieved with our Baltic Sea study. Further, these data, highlighting the transcriptional activity of viruses, represent one of the more powerful uses of omics concerning ecosystem health. The use of omics-related data to assess ecosystem health holds great promise for rapid and relatively inexpensive determination of perturbations and risk, explicitly with regard to viral assemblages, as no single marker gene is suitable for widespread taxonomic coverage.
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Petersen, Jillian M., et Benedict Yuen. « The symbiotic ‘all-rounders’ : Partnerships between marine animals and chemosynthetic nitrogen-fixing bacteria ». Applied and Environmental Microbiology, 18 décembre 2020, AEM.02129–20. http://dx.doi.org/10.1128/aem.02129-20.
Texte intégralRésumé :
Nitrogen fixation is a widespread metabolic trait in certain types of microorganisms called diazotrophs. Bioavailable nitrogen is limited in various habitats on land and in the sea, and accordingly, a range of plant, animal, and single-celled eukaryotes have evolved symbioses with diverse diazotrophic bacteria, with enormous economic and ecological benefits. Until recently, all known nitrogen-fixing symbionts were heterotrophs such as nodulating rhizobia, or photoautotrophs such as cyanobacteria. In 2016, the first chemoautotrophic nitrogen-fixing symbionts were discovered in a common family of marine clams, the Lucinidae. Chemosynthetic nitrogen-fixing symbionts use the chemical energy stored in reduced sulfur compounds to power carbon and nitrogen fixation, making them metabolic ‘all-rounders’ with multiple functions in the symbiosis. This distinguishes them from heterotrophic symbionts that require a source of carbon from their host, and their chemosynthetic metabolism distinguishes them from photoautotrophic symbionts that produce oxygen, a potent inhibitor of nitrogenase. In this review, we consider evolutionary aspects of this discovery, by comparing strategies that have evolved for hosting intracellular nitrogen-fixing symbionts in plants and animals. The symbiosis between lucinid clams and chemosynthetic nitrogen-fixing bacteria also has important ecological impacts, as they form a nested symbiosis with endangered marine seagrasses. Notably, nitrogen fixation by lucinid symbionts may help support seagrass health by providing a source of nitrogen in seagrass habitats. These discoveries were enabled by new techniques for understanding the activity of microbial populations in natural environments. However, an animal (or plant) host represents a diverse landscape of microbial niches due to its structural, chemical, immune and behavioural properties. In future, methods that resolve microbial activity at the single cell level will provide radical new insights into the regulation of nitrogen fixation in chemosynthetic symbionts, shedding new light on the evolution of nitrogen-fixing symbioses in contrasting hosts and environments.
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Kubickova, Barbara, Carmel Ramwell, Klara Hilscherova et Miriam Naomi Jacobs. « Highlighting the gaps in hazard and risk assessment of unregulated Endocrine Active Substances in surface waters : retinoids as a European case study ». Environmental Sciences Europe 33, no 1 (13 février 2021). http://dx.doi.org/10.1186/s12302-020-00428-0.
Texte intégralRésumé :
AbstractRegulatory hazard and risk assessment of endocrine-active substances currently specifies four modes of action: interference with sex hormone (oestrogen, androgen) pathways, steroidogenesis, and thyroid hormone signalling. This does not encompass the full complexity of the endocrine system and its extended interfaces with environmental pollutants that can potentially disrupt the carefully maintained balance. Here we take the retinoid signalling pathway as a European case study for both, under- and unregulated endocrine pathways and outline the different levels of interference, discuss their adversity, and indicate crosstalk to other signalling pathways. Retinoid compounds already exist in drinking water sources, occur naturally in cyanobacterial blooms and/or enter surface waters via wastewater discharge, where they pose a potential hazard to the environment and human health - a situation that can be expected to worsen due to water shortages induced by climate-change and population growth. We briefly review relevant aspects of current endocrine disruptor (ED) testing for regulatory purposes and then expand upon the needs for inclusion of disruption of retinoid signalling in (ED) regulatory safety assessment contributing to adverse health outcomes that include cognitive function and neurological disease. An overview of developmental effects of retinoid signalling disruption across species highlights critical processes and potential crosstalk with other signalling pathways. A focused weight of evidence-based evaluation of the biologically plausible associations between neurological disorders and altered retinoid signalling highlights the evidence gaps. We show that monitoring only a limited number of anthropogenic priority chemicals in water is insufficient to address the environmental risks of retinoid signalling disruption. To comprehensively assess impacts on the endpoints, processes, and pathways of the endocrine system that are most vulnerable to chemical interference we need further investigation of the true mixture composition in environmental matrices. On a weight of evidence-basis this information can then be integrated into a reliable, inclusive, quantitative approach that ultimately accommodates all the critical pathways. By focusing on the retinoid signalling pathway, we intend to improve the scope and relevance of an integrated approach for the risk assessment of endocrine disruptors.
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Zhang, Chiqian, Ke Qin, Ian Struewing, Helen Buse, Jorge Santo Domingo, Darren Lytle et Jingrang Lu. « The Bacterial Community Diversity of Bathroom Hot Tap Water Was Significantly Lower Than That of Cold Tap and Shower Water ». Frontiers in Microbiology 12 (23 avril 2021). http://dx.doi.org/10.3389/fmicb.2021.625324.
Texte intégralRésumé :
Microbial drinking water quality in premise plumbing systems (PPSs) strongly affects public health. Bacterial community structure is the essential aspect of microbial water quality. Studies have elucidated the microbial community structure in cold tap water, while the microbial community structures in hot tap and shower water are poorly understood. We sampled cold tap, hot tap, and shower water from a simulated PPS monthly for 16 consecutive months and assessed the bacterial community structures in those samples via high-throughput sequencing of bacterial 16S rRNA genes. The total relative abundance of the top five most abundant phyla (Proteobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, and Firmicutes) was greater than 90% among the 24 identified phyla. The most abundant families were Burkholderiaceae, Sphingomonadaceae, unclassified Alphaproteobacteria, unclassified Corynebacteriales, and Mycobacteriaceae. A multiple linear regression suggests that the bacterial community diversity increased with water temperature and the age of the simulated PPS, decreased with total chlorine residual concentration, and had a limited seasonal variation. The bacterial community in hot tap water had significantly lower Shannon and Inverse Simpson diversity indices (p < 0.05) and thus a much lower diversity than those in cold tap and shower water. The paradoxical results (i.e., diversity increased with water temperature, but hot tap water bacterial community was less diverse) were presumably because (1) other environmental factors made hot tap water bacterial community less diverse, (2) the diversity of bacterial communities in all types of water samples increased with water temperature, and (3) the first draw samples of hot tap water could have a comparable or even lower temperature than shower water samples and the second draw samples of cold tap water. In both a three-dimensional Non-metric multidimensional scaling ordination plot and a phylogenetic dendrogram, the samples of cold tap and shower water cluster and are separate from hot tap water samples (p < 0.05). In summary, the bacterial community in hot tap water in the simulated PPS had a distinct structure from and a much lower diversity than those in cold tap and shower water.