In Situ Collection and Preservation of Intact Microcystis Colonies to Assess Population Diversity and Microcystin Quotas.

Jonathan Puddick,Ian Hawes,David P Hamilton,Eric O Goodwin,Susanna A Wood

doi:10.3390/toxins11080435

Jonathan Puddick, Ian Hawes + Show 3 more

Open Access

https://doi.org/10.3390/toxins11080435

Copy DOI

Abstract

Understanding of colony specific properties of cyanobacteria in the natural environment has been challenging because sampling methods disaggregate colonies and there are often delays before they can be isolated and preserved. Microcystis is a ubiquitous cyanobacteria that forms large colonies in situ and often produces microcystins, a potent hepatotoxin. In the present study a new cryo-sampling technique was used to collect intact Microcystis colonies in situ by embedding them in a sheet of ice. Thirty-two of these Microcystis colonies were investigated with image analysis, liquid chromatography-mass spectrometry, quantitative polymerase chain reaction and high-throughput sequencing to assess their volume, microcystin quota and internal transcribed spacer (ITS) genotype diversity. Microcystin quotas were positively correlated to colony volume (R2 = 0.32; p = 0.004). Individual colonies had low Microcystis ITS genotype diversity and one ITS operational taxonomic unit predominated in all samples. This study demonstrates the utility of the cryo-sampling method to enhance the understanding of colony-specific properties of cyanobacteria with higher precision than previously possible.

Highlights

Key Contribution: Using a new cryo-sampling technique this study demonstrates a positive relationship between Microcystis colony size and microcystin quotas
Microcystis is a common genus of bloom-forming freshwater cyanobacteria that is frequently associated with the production of the cyanotoxin microcystin [1]
Microcystis colonies were collected in situ from three locations at Lake Rotorua (Kaikoura, New Zealand) using a cryo-sampling technique designed to encapsulate cyanobacterial colonies in a sheet of ice

Summary

Introduction

Microcystis is a common genus of bloom-forming freshwater cyanobacteria that is frequently associated with the production of the cyanotoxin microcystin [1]. Potentially made up of hundreds of thousands of cells, are held together in an organic matrix comprised of a range of secreted organic polymers such as polysaccharides, nucleic acids, phospholipids and/or proteins [3,4]. The toxins predominantly affect the liver cells of mammals as they cannot be translocated across the membranes of most tissues and are actively transported into hepatocytes [7] by organic anion-transporting. Inhibition of hepatocyte protein phosphatases results in excessive signaling, leading to cellular disruption due to intermediate filaments of cytokeratin in the cytoskeleton becoming hyperphosphorylated [9], or cell proliferation and tumor promotion [10]

Methods

Results

Conclusion