Article

Phylogeography of the invasive cyanobacterium Cylindrospermopsis raciborskii

School of Microbiology and Immunology, University of New South Wales, Sydney, New South Wales 2051, Australia.
Molecular Ecology (Impact Factor: 5.84). 02/2003; 12(1):133-40. DOI: 10.1046/j.1365-294X.2003.01709.x
Source: PubMed

ABSTRACT Cylindrospermopsis raciborskii is a planktonic freshwater cyanobacterium that has become increasingly prevalent in tropical and temperate water bodies world-wide. This species is of concern from a water-quality perspective because of its known ability to produce toxins that can affect the health of humans and other animals. This study investigates genetic variation between strains of C. raciborskii isolated from freshwater rivers and reservoirs in Australia, Brazil, Germany, Hungary, Portugal and the USA. Strains were first characterized by analysis of their 16S rRNA gene nucleotide sequences and were found to have a sequence divergence of 99.1%. A phylogenetic tree, constructed using the 16S rRNA gene sequences showed that strains grouped into Australian, European and North/South American phylotypes. To investigate further the observed separation of strains into geographically distinct groups, we applied a cyanobacterium-specific short tandem repeat sequence technique, HIP1. An electrophoretic comparison of the HIP1 polymerase chain reaction products showed clear distinctions between the C. raciborskii strains. A phylogenetic tree, based on the repeat element banding patterns, also revealed three distinct groups of C. raciborskii strains. The first group consisted of strains from the USA and Brazil; the second comprised European strains from Germany, Hungary and Portugal; and the third were strains from Australia. In general, between-country variation was greater than within-country variation, indicating that this fingerprinting technique can successfully distinguish C. raciborskii strains taken from different global locations. The relationship between toxicity and the observed HIP1 polymerase chain reaction fingerprint profiles was less clear, although it is interesting to note that of the strains analysed in this study, only Australian strains are known to produce cylindrospermopsin and only Brazilian strains have been reported to produce paralytic shellfish poisoning toxins.

Download full-text

Full-text

Available from: Martin L Saker, Jun 09, 2014
0 Followers
 · 
138 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Eutrophication damages water supply by promoting the proliferation of potentially toxin-producing cyanobacteria. In Ceara State, the abundance of these algae in artificial reservoirs has been reaching up to 95% phytoplankton density of cells. The knowledge of the species growth dynamics depending on the availability of nutrients can promote the understanding of a recurring natural phenomenon, the cyanobacteria blooms. This study aimed to evaluate the influence of macronutrient depletion on the development of C. raciborskii T3 cultures. Experiments were conducted in ASM-1 medium and variations with the removal of 75 and 50% phosphorus and nitrogen from its original composition. Cultures were grown in non-axenic conditions, under constant light of 6.75 μ.mol.m-2 .s-1 , 12: 12 photoperiod, and at temperature of 24 ± 2ºC. Nitrogen-depleted cultures clearly showed lower growth in comparison with other experiments, reaching the stationary phase earlier, besides lower cell concentrations. Whereas, phosphorus-depleted cultures presented steeper growth curves, similar to the growth registered in the regular ASM-1 medium, and thereby demonstrating that under these experimental conditions, nitrogen was the limiting nutrient for the growth of C. raciborskii.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Molecular assessment of a large portion of traditional cyanobacterial taxa has been hindered by the failure to isolate and grow them in culture. In this study, we developed an optimized protocol for single cell/filament isolation and 16S rRNA gene sequencing of terrestrial cyanobacteria with large mucilaginous sheaths, and applied it to determine the phylogenetic position of typical members of the genera Petalonema and Stigonema. A methodology based on a glass-capillary isolation technique and a semi-nested PCR protocol enabled reliable sequencing of the 16S rRNA gene from all samples analysed. Ten samples covering 7 species of Stigonema from Europe, North and Central America, and Hawaii, and the type species of Petalonema from Slovakia were sequenced. Contrary to some previous studies, which proposed a relation to heteropolar nostocalean cyanobacteria, Petalonema appeared to belong to the family Scytonemataceae. Analysis of Stigonema specimens recovered a unique coherent phylogenetic cluster, substantially broadening our knowledge of the molecular diversity within this genus. Neither the uni- to biseriate species nor the multiseriate species formed monophyletic subclusters within the genus.Typical multiseriate species of Stigonema clustered in a phylogenetic branch derived from uni- to biseriate S. ocellatum Thuret ex Bornet & Flahault in our analysis, suggesting that species with more complex thalli may have evolved from the more simple ones. We propose the technique tested in this study as a promising tool for a future revision of the molecular taxonomy in cyanobacteria.This article is protected by copyright. All rights reserved.
    Journal of Phycology 02/2015; 51(2). DOI:10.1111/jpy.12273 · 2.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Highly iterated palindromes (HIP) have been used as high resolution molecular markers for assessing the genetic variability and phylogenetic relatedness of heterocystous cyanobacteria (subsections IV and V) representing 12 genera of heterocystous cyanobacteria, collected from different geographical areas of India. DNA fingerprints generated using four HIP markers viz. HIP-AT, HIP-CA, HIP-GC, and HIP-TG showed 100 % polymorphism in all the heterocystous cyanobacteria studied and each marker produced unique and strain-specific banding pattern. Furthermore, phylogenetic affinities based on the dendrogram constructed using HIP DNA profiles of heterocystous cyanobacteria suggest the monophyletic origin of this entire heterocystous clade along with a clear illustration of the polyphyletic origin of the branched Stigonematalean order (Subsection V). In addition, phylogenetic affinities were validated by principal component analysis of the HIP fingerprints. The overall data obtained by both the phylogeny and principal component assessments proved that the entire heterocystous clade was intermixed, and there are immediate needs for classificatory reforms that satisfy morphological plasticity and environmental concerns.
    Physiology and Molecular Biology of Plants 07/2014; DOI:10.1007/s12298-014-0244-4