A qPCR-Based Tool to Diagnose the Presence of Harmful Cyanobacteria and Cyanotoxins in Drinking Water Sources

Chiu, Ying-Ta; Chen, Yi Hsuan; Wang, Ting Shaun; Yen, H. H.; Lin, Tsair Fuh

doi:10.3390/ijerph14050547

Cited by 30 publications

(20 citation statements)

References 79 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The morphospecies M. aeruginosa have been identified in brackish water blooming from El-Manzala Lake, Damietta, Egypt. Some species including M. aeruginosa are often found in North African freshwater habitats (Nasri et al, 2004) and drinking water sources (Chiu et al, 2017). The phylogenetic tree based on the 16S rDNA analysis confirmed the identification of the M. aeruginosa MDEG1 isolate as it exhibited high identity reached 99% -100% in one cluster with some Microcystis species including other M. aeruginosa strains.…”

Section: Discussionsupporting

confidence: 53%

Characterization and Antibacterial Effects of Microcystis aeruginosa Extracts

2019

View full text Add to dashboard Cite

M ICROCYSTIS aeruginosa MDEG1 strain from El-Manzala Lake (Damietta, Egypt) was identified classically by its morphological characteristics. Its identification was confirmed using 16S rRNA gene sequencing. Different concentrations (1, 10, 25 and 50mg/ ml) of petroleum ether and chloroform of M. aeruginosa MDEG1 extracts were examined for their antibacterial activity by well diffusion technique. Petroleum ether extract had a high activity against K. pneumoniae, P. aeruginosa and S. aureus. Chloroform extract exhibited higher activity against K. pneumoniae. Gas chromatography, mass spectrophotometry (GC-MS) and H-proton nuclear magnetic resonance ( 1 H-NMR) analysis revealed the presence of Hexadecanoic acid (Palmitic acid) and its methyl ester derivative as major constituents of petroleum ether and chloroform algal extract, that might be involved in their antibacterial activity. The cytomorphology using scanning electron microscopy (SEM) for treated K. pneumonia (Nosocomial infection bacteria) with M. aeruginosa extract (Chloroform, 50mg/ ml) showed appearance of giant cell formation, while transmission electron microscope (TEM) showed ruptured bacterial cell wall damage with extrusion of cytoplasmic content indicating its bactericidal effect.

show abstract

Section: Discussionsupporting

confidence: 53%

Characterization and Antibacterial Effects of Microcystis aeruginosa Extracts

2019

View full text Add to dashboard Cite

show abstract

“…Moreover, several studies (reviewed in [31]) indicate that microcystin production, and the level of toxicity in blooms, are influenced by environmental conditions, but also by the indirect effects of environment on cellular division and growth [31,37]. Furthermore, it has been shown that there is considerable temporal and spatial variation in microcystin production, and that microcystin variants vary in cytotoxicity [17,[38][39][40]. Altogether this illustrates that the function of microcystin variants as well as their dynamics and distribution is not fully understood, and warrants further investigation.…”

Section: Introductionmentioning

confidence: 99%

High Diversity of Microcystin Chemotypes within a Summer Bloom of the Cyanobacterium Microcystis botrys

Johansson

Legrand

Björnerås

et al. 2019

Toxins

View full text Add to dashboard Cite

The fresh-water cyanobacterium Microcystis is known to form blooms world-wide, and is often responsible for the production of microcystins found in lake water. Microcystins are non-ribosomal peptides with toxic effects, e.g. on vertebrates, but their function remains largely unresolved. Moreover, not all strains produce microcystins, and many different microcystin variants have been described. Here we explored the diversity of microcystin variants within Microcystis botrys, a common bloom-former in Sweden. We isolated a total of 130 strains through the duration of a bloom in eutrophic Lake Vomb, and analyzed their microcystin profiles with tandem mass spectrometry (LC-MS/MS). We found that microcystin producing (28.5%) and non-producing (71.5%) M. botrys strains, co-existed throughout the bloom. However, microcystin producing strains were more prevalent towards the end of the sampling period. Overall, 26 unique M. botrys chemotypes were identified, and while some chemotypes re-occurred, others were found only once. The M. botrys chemotypes showed considerable variation both in terms of number of microcystin variants, as well as in what combinations the variants occurred. To our knowledge, this is the first report on microcystin chemotype variation and dynamics in M. botrys. In addition, our study verifies the co-existence of microcystin and non-microcystin producing strains, and we propose that environmental conditions may be implicated in determining their composition. Key Contribution:This study demonstrates that a single bloom of Microcystis botrys consists of strains with different microcystin chemotypes, each producing from zero up to 12 different microcystin variants. We established that microcystin and non-microcystin producing strains co-occur, and that the chemotype composition varies during the bloom.Toxins 2019, 11, 698 2 of 16 bloom-forming cyanobacteria, and that harmful blooms will increase both in frequency and duration, due to direct and indirect effects of changes in hydrological cycling, increased water temperatures, and nutrient loading [4][5][6][7][8][9].In addition to forming dense blooms which can deteriorate water quality per se, many cyanobacterial genera produce secondary metabolites with significant bioactivity and toxicity to aquatic organisms and humans [10][11][12][13][14]. In freshwaters, microcystins are among the most common cyanotoxins [7,15]. These inhibit the eukaryotic protein phosphatases 1 and 2a, and have hepatotoxic effects in vertebrates [10,16,17]. Drinking water from surface water supplies must therefore be checked for microcystin content, and may not be higher than 1 µg microcystin L −1 according to WHO regulation. Microcystins are cyclic heptapeptides (Figure 1) and are produced by several cyanobacteria including Microcystis, Planktothrix, and Anabaena (Dolichospermum) [14,18,19]. The common structure and biosynthetic pathway of microcystin synthesis in these genera have been described [20][21][22][23][24][25]. In Microcystis, the microcystin synthetase gene cluster co...

show abstract

“…They also examined the ratio of the mcyE gene to the cpcA gene as a measure of toxigenicity, finding highly variable ratios at different areas of the lake. Further work by Chiu et al [ 60 ] found similarly high correlations between qPCR results on eDNA with cyanotoxins with a multiplexed qPCR approach that simultaneously quantified genes from two common CHAB genera, Microcystis and Cylindrospermopsis . Although more work in correlating cellular biomass and eDNA concentrations in specific conditions is needed to use eDNA as an absolute measure of cyanobacteria abundance, relative abundance can be estimated with similar conditions between sampling sites.…”

Section: Discussionmentioning

confidence: 90%

“…Work on developing qPCR protocols for detecting toxic cyanobacterial strains have found high correlation between the presence of the mcy gene family and microcystins [ 59 ]. qPCR has also been used for the quantification of environmental bacterial samples and have corresponded with high precision to absolute cell numbers [ 60 ]. Otten et al [ 36 ] used the Microcystis mcyE and cpcA genes to quantify the presence of toxigenic and total Microcystis in Lake Taihu, China, and found significant positive correlations between microcystin concentration and concentrations of both genes.…”

Section: Discussionmentioning

confidence: 99%

Depth-Dependent Spatiotemporal Dynamics of Overwintering Pelagic Microcystis in a Temperate Water Body

et al. 2021

View full text Add to dashboard Cite

Cyanobacteria in the genus Microcystis are dominant components of many harmful algal blooms worldwide. Their pelagic–benthic life cycle helps them survive periods of adverse conditions and contributes greatly to their ecological success. Many studies on Microcystis overwintering have focused on benthic colonies and suggest that sediment serves as the major inoculum for subsequent summer blooms. However, the contemporaneous overwintering pelagic population may be important as well but is understudied. In this study, we investigated near-surface and near-bottom pelagic population dynamics of both microcystin-producing Microcystis and total Microcystis over six weeks in winter at Dog Lake (South Frontenac, ON, Canada). We quantified relative Microcystis concentrations using real-time PCR. Our results showed that the spatiotemporal distribution of overwintering pelagic Microcystis was depth dependent. The abundance of near-bottom pelagic Microcystis declined with increased depth with no influence of depth on near-surface Microcystis abundance. In the shallow region of the lake (<10 m), most pelagic Microcystis was found near the lake bottom (>90%). However, the proportion of near-surface Microcystis rose sharply to over 60% as the depth increased to approximately 18 m. The depth-dependent distribution pattern was found to be similar in both microcystin-producing Microcystis and total Microcystis. Our results suggest the top of the water column may be a more significant contributor of Microcystis recruitment inoculum than previously thought and merits more attention in early CHAB characterization and remediation.

show abstract

A qPCR-Based Tool to Diagnose the Presence of Harmful Cyanobacteria and Cyanotoxins in Drinking Water Sources

Cited by 30 publications

References 79 publications

Characterization and Antibacterial Effects of Microcystis aeruginosa Extracts

Characterization and Antibacterial Effects of Microcystis aeruginosa Extracts

High Diversity of Microcystin Chemotypes within a Summer Bloom of the Cyanobacterium Microcystis botrys

Depth-Dependent Spatiotemporal Dynamics of Overwintering Pelagic Microcystis in a Temperate Water Body

Contact Info

Product

Resources

About