scholarly journals Optimized culturing conditions for an algicidal bacterium Pseudoalteromonas sp. SP 48 on harmful algal blooms caused by Alexandrium tamarense

2019 ◽  
Vol 8 (8) ◽  
Author(s):  
Yi‐Hua Lyu ◽  
Yue‐Xia Zhou ◽  
Yi Li ◽  
Jin Zhou ◽  
Yi‐Xiao Xu
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Alexandrium Tamarense ◽  
Algicidal Bacterium ◽  
Culturing Conditions

scholarly journals Study on the metabolites of DH-e, a Halomonas marine bacterium, against three toxic dinoflagellate species

2018 ◽  
Vol 78 (7) ◽  
pp. 1535-1544 ◽  
Author(s):  
Di Wang ◽  
Liling Xie ◽  
Xingbiao Zhu ◽  
Xiao Bi ◽  
Yuzhong Zheng ◽  
...  
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Morphological Characteristics ◽  
Alexandrium Tamarense ◽  
Algicidal Bacteria ◽  
Bacterial Strains ◽  
16S Rdna Sequence ◽  
Algicidal Bacterium ◽  
16S Rdna Sequence Analysis ◽  
Acetone Peroxide

Abstract Algicidal bacteria play an important role in mitigating harmful algal blooms (HABs). In the study, five bacterial strains were isolated from the East China Sea. One strain of algicidal bacterium, named DH-e, was found to selectively inhibit the motor ability of Prorocentrum donghaiense, Alexandrium tamarense (ATDH-47) and Karenia mikimotoi Hansen. Both 16S rDNA sequence analysis and morphological characteristics revealed that the algicidal DH-e bacterium belonged to Halomonas. Furthermore, results showed that the metabolites in the DH-e cell-free filtrate could kill algae directly, and the minimum inhibitory concentrations (MICs) of the bacterial metabolites on the cells of the three dinoflagellate species ranged from 35.0–70.0 μg/mL. Following short-term inhibitory tests, the dinoflagellates in mixed crude extract solution (0.7 mg/mL) ceased movement after 5 min. The algicidal mechanism of the metabolites was investigated through enzyme activities, including that of catalase (CAT), alkaline phosphatase (AKP), acetone peroxide (T-ATP) synthetase and nitrite reductase (NR). Results indicated that metabolites did not disrupt the energy or nutrient routes of the algae (P > 0.05), but did initiate an increase in free radicals in the algal cells, which might explain the subsequent death of sensitive algae. Thus, the metabolites of the DH-e bacterium showed promising potential for controlling HABs.

scholarly journals Biochemical and Physiological Responses of Harmful Karenia mikimotoi to Algicidal Bacterium Paracoccus homiensis O-4

2021 ◽  
Vol 12 ◽  
Author(s):  
Ning Ding ◽  
Yanbing Wang ◽  
Junfeng Chen ◽  
Siyu Man ◽  
Feng Lan ◽  
...  
Keyword(s):  
Photosynthetic Pigments ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Physiological Responses ◽  
Antioxidant Defenses ◽  
Algicidal Bacteria ◽  
Antioxidant Systems ◽  
Karenia Mikimotoi ◽  
Algicidal Bacterium ◽  
And Control

Harmful algal blooms caused by Karenia mikimotoi frequently occur worldwide and severely threaten the marine environment. In this study, the biochemical and physiological responses of K. mikimotoi to the algicidal bacterium Paracoccus homiensis O-4 were investigated, and the effects on the levels of reactive oxygen species (ROS), malondialdehyde content, multiple antioxidant systems and metabolites, photosynthetic pigments, and photosynthetic index were examined. The cell-free supernatant in strain O-4 significantly inhibited K. mikimotoi cell growth. The bacterium caused the K. mikimotoi cells to activate their antioxidant defenses to mitigate ROS, and this effect was accompanied by the upregulation of intracellular antioxidant enzymes and non-enzyme systems. However, the overproduction of ROS induced lipid peroxidation and oxidative damage within K. mikimotoi cells, ultimately leading to algal death. In addition, the photosynthetic efficiency of the algal cells was significantly inhibited by O-4 and was accompanied by a reduction in photosynthetic pigments. This study indicates that O-4 inhibits K. mikimotoi through excessive oxidative stress and impaired photosynthesis. This research into the biochemical and physiological responses of K. mikimotoi to algicidal bacteria provides insights into the prophylaxis and control of harmful algal blooms via interactions between harmful algae and algicidal bacteria.

scholarly journals Intraspecific facilitation by allelochemical mediated grazing protection within a toxigenic dinoflagellate population

2015 ◽  
Vol 282 (1798) ◽  
pp. 20141268 ◽  
Author(s):  
Uwe John ◽  
Urban Tillmann ◽  
Jennifer Hülskötter ◽  
Tilman J. Alpermann ◽  
Sylke Wohlrab ◽  
...  
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Phenotypic Diversity ◽  
Marine Ecosystem ◽  
Paralytic Shellfish Poisoning ◽  
Alexandrium Tamarense ◽  
Shellfish Poisoning ◽  
Coastal Marine ◽  
The Impact ◽  
Intraspecific Facilitation

Dinoflagellates are a major cause of harmful algal blooms (HABs), with consequences for coastal marine ecosystem functioning and services. Alexandrium fundyense (previously Alexandrium tamarense ) is one of the most abundant and widespread toxigenic species in the temperate Northern and Southern Hemisphere and produces paralytic shellfish poisoning toxins as well as lytic allelochemical substances. These bioactive compounds may support the success of A. fundyense and its ability to form blooms. Here we investigate the impact of grazing on monoclonal and mixed set-ups of highly (Alex2) and moderately (Alex4) allelochemically active A. fundyense strains and a non-allelochemically active conspecific (Alex5) by the heterotrophic dinoflagellate Polykrikos kofoidii . While Alex4 and particularly Alex5 were strongly grazed by P. kofoidii when offered alone, both strains grew well in the mixed assemblages (Alex4 + Alex5 and Alex2 + Alex5). Hence, the allelochemical active strains facilitated growth of the non-active strain by protecting the population as a whole against grazing. Based on our results, we argue that facilitation among clonal lineages within a species may partly explain the high genotypic and phenotypic diversity of Alexandrium populations. Populations of Alexandrium may comprise multiple cooperative traits that act in concert with intraspecific facilitation, and hence promote the success of this notorious HAB species.

scholarly journals sxtA-Based Quantitative Molecular Assay To Identify Saxitoxin-Producing Harmful Algal Blooms in Marine Waters

2011 ◽  
Vol 77 (19) ◽  
pp. 7050-7057 ◽  
Author(s):  
Shauna A. Murray ◽  
Maria Wiese ◽  
Anke Stüken ◽  
Steve Brett ◽  
Ralf Kellmann ◽  
...  
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Harmful Algal Bloom ◽  
Effective Means ◽  
Molecular Genetic ◽  
Alexandrium Tamarense ◽  
Alexandrium Catenella ◽  
Content Type ◽  
Eukaryotic Phytoplankton ◽  
Novel Method

ABSTRACTThe recent identification of genes involved in the production of the potent neurotoxin and keystone metabolite saxitoxin (STX) in marine eukaryotic phytoplankton has allowed us for the first time to develop molecular genetic methods to investigate the chemical ecology of harmful algal bloomsin situ. We present a novel method for detecting and quantifying the potential for STX production in marine environmental samples. Our assay detects a domain of the genesxtAthat encodes a unique enzyme putatively involved in thesxtpathway in marine dinoflagellates,sxtA4. A product of the correct size was recovered from nine strains of four species of STX-producingAlexandriumandGymnodinium catenatumand was not detected in the non-STX-producingAlexandriumspecies, other dinoflagellate cultures, or an environmental sample that did not contain known STX-producing species. However,sxtA4was also detected in the non-STX-producing strain ofAlexandrium tamarense, Tasmanian ribotype. We investigated the copy number ofsxtA4in three strains ofAlexandrium catenellaand found it to be relatively constant among strains. Using our novel method, we detected and quantifiedsxtA4in three environmental blooms ofAlexandrium catenellathat led to STX uptake in oysters. We conclude that this method shows promise as an accurate, fast, and cost-effective means of quantifying the potential for STX production in marine samples and will be useful for biological oceanographic research and harmful algal bloom monitoring.

scholarly journals A Novel Algicidal Bacterium, Microbulbifer sp. YX04, Triggered Oxidative Damage and Autophagic Cell Death in Phaeocystis globosa , Which Causes Harmful Algal Blooms

2022 ◽  
Author(s):  
Xiaoying Zhu ◽  
Shuangshuang Chen ◽  
Guiying Luo ◽  
Wei Zheng ◽  
Yun Tian ◽  
...  
Keyword(s):  
Cell Death ◽  
Oxidative Damage ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Algal Bloom ◽  
Harmful Algal Bloom ◽  
Health Hazard ◽  
Autophagic Cell Death ◽  
Phaeocystis Globosa ◽  
Algicidal Bacterium

P. globosa is one of the most notorious harmful algal bloom (HAB)-causing species, which can secrete hemolytic toxins, frequently cause serious ecological pollution, and pose a health hazard to animals and humans. Hence, screening for bacteria with high algicidal activity against P. globosa and studies on the algicidal characteristics and mechanism will contribute to providing an ecofriendly microorganism-controlling agent for preventing the occurrence of algal blooms and reducing the harm of algal blooms to the environment.

scholarly journals Comparing metabarcoding and morphological approaches to identify phytoplankton taxa associated with harmful algal blooms

FACETS ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 784-811
Author(s):  
Svetlana Esenkulova ◽  
Ben J.G. Sutherland ◽  
Amy Tabata ◽  
Nicola Haigh ◽  
Christopher M. Pearce ◽  
...  
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Quantitative Polymerase Chain Reaction ◽  
Large Subunit ◽  
Molecular Techniques ◽  
Alexandrium Tamarense ◽  
Morphological Identification ◽  
Multiple Markers ◽  
Molecular Approaches ◽  
Polymerase Chain

Molecular techniques are expected to be highly useful in detecting taxa causing harmful algal blooms (HABs). This is the first report in Canada evaluating HABs-related species identification using a combination of morphological and molecular approaches. Microscopy, quantitative polymerase chain reaction (qPCR), and metabarcoding with multiple markers (i.e., 16S, 18S-dinoflagellate and 18S-diatom, large subunit (28S) rDNA) were applied on samples ( n = 54) containing suspected harmful algae (e.g., Alexandrium spp., Chattonella sp., Chrysochromulina spp., Dictyocha spp., Heterosigma akashiwo, Protoceratium reticulatum, Pseudochattonella verruculosa, Pseudo-nitzschia spp., Pseudopedinella sp.). Owing to methodology limitations, qPCR result interpretation was limited, although good detectability occurred using previously published assays for Alexandrium tamarense, H. akashiwo, and P. verruculosa. Overall, the multiple-marker metabarcoding results were superior to the morphology-based methods, with the exception of taxa from the silicoflagellate group. The combined results using both 18S markers and the 28S marker together closely corresponded with morphological identification of targeted species, providing the best overall taxonomic coverage and resolution. The most numerous unique taxa were identified using the 18S-dinoflagellate amplicon, and the best resolution to the species level occurred using the 28S amplicon. Molecular techniques are therefore promising for HABs taxa detection but currently depend on deploying multiple markers for metabarcoding.

scholarly journals Combining metabarcoding and morphological approaches to identify phytoplankton taxa associated with harmful algal blooms

2019 ◽  
Author(s):  
Svetlana Esenkulova ◽  
Ben J.G. Sutherland ◽  
Amy Tabata ◽  
Nicola Haigh ◽  
Christopher M. Pearce ◽  
...  
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Quantitative Polymerase Chain Reaction ◽  
Large Subunit ◽  
Molecular Techniques ◽  
Alexandrium Tamarense ◽  
Morphological Identification ◽  
Multiple Markers ◽  
Molecular Approaches ◽  
Polymerase Chain

AbstractMolecular techniques are expected to be highly useful in detecting taxa causing harmful algal blooms (HABs). This is the first report in Canada evaluating HABs-related species identification using a combination of morphological and molecular approaches. Microscopy, quantitative polymerase chain reaction (qPCR), and metabarcoding with multiple markers (i.e. 16S, 18S-dinoflagellate and 18S-diatom, large subunit (28S) rDNA) were applied on samples (n=54) containing suspected harmful algae (e.g. Alexandrium spp., Chattonella sp., Chrysochromulina spp., Dictyocha spp., Heterosigma akashiwo, Protoceratium reticulatum, Pseudochattonella verruculosa, Pseudo-nitzschia spp., Pseudopedinella sp.). Due to methodology limitations, qPCR result interpretation was limited, although good detectability occurred using previously published assays for Alexandrium tamarense, H. akashiwo, and P. verruculosa. Overall, the multiple-marker metabarcoding results were superior to the morphology-based methods, with the exception of taxa from the silicoflagellate group. The combined results using both 18S markers and the 28S marker together closely corresponded with morphological identification of targeted species, providing the best overall taxonomic coverage and resolution. The most numerous unique taxa were identified using the 18S-dinoflagellate amplicon, and the best resolution to the species level occurred using the 28S amplicon. Molecular techniques are therefore highly useful for HABs taxa detection, but currently depend on deploying multiple markers for metabarcoding.

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