Description of Hydrogenophaga Crocea Sp. Nov. Associated With Cyanobacterial Mat Isolated From Farmland Mud

A catalase and oxidase-positive strain BA0156T was isolated from a cyanobacterial mat collected from the farmland mud cultivated with sugarcane from Ahmednagar, India. The 16S rRNA gene of strain BA0156T showed the highest percent sequence similarity with Hydrogenophaga borbori LMG 30805T (98.55 %), followed by H. flava DSM 619T (98.35 %) and H. intermedia DSM 5680T (98.21 %). The strain BA0156T consisted of major fatty acids, C16:0 (25.1 %) and C17:0 cyclo (3.9 %), whereas phosphatidylethanolamine and diphosphatidylglycerol were the major polar lipids. The OrthoANI and dDDH values between strain BA0156T and its closest relative H. borbori LMG 30805T were 84.59 % and 28.3 %, respectively. The DNA G+C content of strain BA0156T was 69.42 mol %. Furthermore, the biochemical and physiological features of strain BA0156T showed a distinct pattern from their closest phylogenetic neighbours. The phenotypic, genotypic and chemotaxonomic characteristics indicated that the strain BA0156T represents a new species for which the name Hydrogenophaga crocea (type strain BA0156 T = MCC 3062T = KCTC 72452T = JCM 34507T) is proposed.

Omics-Inferred Partitioning and Expression of Diverse Biogeochemical Functions in a Low-O 2 Cyanobacterial Mat Community

Cyanobacterial mats are dense communities of microorganisms that contain photosynthetic cyanobacteria along with a host of other bacterial species that play important yet still poorly understood roles in this ecosystem. Although such cyanobacterial mats were critical agents of Earth’s biological and chemical evolution through geological time, little is known about how they function under the low-oxygen conditions that characterized most of their natural history.

Bloom Forming and Toxic Cyanobacteria in New Zealand Species Diversity and Distribution, Cyanotoxin Production and Accumulation of Microcystins in Selected Freshwater Organisms

<p>The objective of this doctoral study was to identify waterbodies in New Zealand containing cyanobacterial blooms and mats, to assess the species composition and to establish types and concentrations of cyanotoxins in samples obtained. A total of 271 water and cyanobacterial mat samples from 147 different waterbodies around New Zealand were collected or received between January 2001 and December 2004. Sixty seven percent were found to contain cyanobacteria and 4l% of the samples contained cyanobacteria in sufficiently high concentrations to be termed a bloom. A total of 54 different cyanobacteria species were recorded. Prior to 1987, 33 lakes in New Zealand were recorded as having experienced cyanobacterial blooms. In the present study an additional 18 lakes were recorded as having experienced blooms. Eight bloom forming cyanobacteria species not previously identified in New Zealand (Anabaena planktonica, Cylindrospermopsis raciborskii, Microcystis botrys, M. panniformis, M. icthtyoblabe, M. wesenbergii, Planktothrix peronata f. attenuata and Sphaerocavum brasiliense) were found to be dominant or co-dominant in at least some cyanobacterial blooms. In addition to these species, three non-dominant species were identified that were also new records for New Zealand. The water and cyanobacterial mat samples were analysed using ELISA's, LC/MS, HPLC and neuroblastoma assays for cyanotoxins and identified; microcystins/nodularins (102 samples from 54 different locations), anatoxin-a (3 samples from 3 different locations), cylindrospermopsins (l sample) and saxitoxins (48 santples from 4l different locations). Species from the genera Microcystis, Anabaena, Cylindrospermopsis, Nostoc, Planktothrix, Oscillatoria and Phormidium produce these cyanotoxins. An in-depth study in Lakes Rotoehu and Rotoiti investigated the relationship between cyanobacteria species composition and levels of microcystins over a six month period and examined accumulation of microcystins in rainbow trout (Oncorhynchtts mykiss) and freshwater mussels (Hydridella menziesi). Weekly water samples collected from both lakes showed that cyanobacteria species and levels of microcystins can vary over time during a bloom event. When phytoplankton samples were dominated by very high cell concentration of Microcystis spp. they were found to contain microcystins. Generally cell counts were found to be a poor indicator of levels of microcystins in the water samples, suggesting that cell counts alone are not a satisfactory way of identifying human health dangers in waterbodies containing cyanobacteria. Microcystins were detected in rainbow trout liver and muscle tissue, and in freshwater mussels. The Total Daily Intake of microcystins recommended by the World Health Organisation for humans is 0.04 pg kg-1 tdoy-1. A 70kg human consuming 300g of muscle tissue would have exceeded this level in 50% (Lake Rotoiti) and 7l% (Lake Rotoehu) of the samples. Health problems could result if more than 300 g of trout muscle tissue was consumed on a regular basis over an extended period. This study has demonstrated that the prevalence of freshwater cyanotoxin-producing cyanobacteria is widespread in New Zealand waterbodies and these cyanotoxins pose a potential health risk to both humans and animals either directly or indirectly.</p>

Bloom Forming and Toxic Cyanobacteria in New Zealand Species Diversity and Distribution, Cyanotoxin Production and Accumulation of Microcystins in Selected Freshwater Organisms

<p>The objective of this doctoral study was to identify waterbodies in New Zealand containing cyanobacterial blooms and mats, to assess the species composition and to establish types and concentrations of cyanotoxins in samples obtained. A total of 271 water and cyanobacterial mat samples from 147 different waterbodies around New Zealand were collected or received between January 2001 and December 2004. Sixty seven percent were found to contain cyanobacteria and 4l% of the samples contained cyanobacteria in sufficiently high concentrations to be termed a bloom. A total of 54 different cyanobacteria species were recorded. Prior to 1987, 33 lakes in New Zealand were recorded as having experienced cyanobacterial blooms. In the present study an additional 18 lakes were recorded as having experienced blooms. Eight bloom forming cyanobacteria species not previously identified in New Zealand (Anabaena planktonica, Cylindrospermopsis raciborskii, Microcystis botrys, M. panniformis, M. icthtyoblabe, M. wesenbergii, Planktothrix peronata f. attenuata and Sphaerocavum brasiliense) were found to be dominant or co-dominant in at least some cyanobacterial blooms. In addition to these species, three non-dominant species were identified that were also new records for New Zealand. The water and cyanobacterial mat samples were analysed using ELISA's, LC/MS, HPLC and neuroblastoma assays for cyanotoxins and identified; microcystins/nodularins (102 samples from 54 different locations), anatoxin-a (3 samples from 3 different locations), cylindrospermopsins (l sample) and saxitoxins (48 santples from 4l different locations). Species from the genera Microcystis, Anabaena, Cylindrospermopsis, Nostoc, Planktothrix, Oscillatoria and Phormidium produce these cyanotoxins. An in-depth study in Lakes Rotoehu and Rotoiti investigated the relationship between cyanobacteria species composition and levels of microcystins over a six month period and examined accumulation of microcystins in rainbow trout (Oncorhynchtts mykiss) and freshwater mussels (Hydridella menziesi). Weekly water samples collected from both lakes showed that cyanobacteria species and levels of microcystins can vary over time during a bloom event. When phytoplankton samples were dominated by very high cell concentration of Microcystis spp. they were found to contain microcystins. Generally cell counts were found to be a poor indicator of levels of microcystins in the water samples, suggesting that cell counts alone are not a satisfactory way of identifying human health dangers in waterbodies containing cyanobacteria. Microcystins were detected in rainbow trout liver and muscle tissue, and in freshwater mussels. The Total Daily Intake of microcystins recommended by the World Health Organisation for humans is 0.04 pg kg-1 tdoy-1. A 70kg human consuming 300g of muscle tissue would have exceeded this level in 50% (Lake Rotoiti) and 7l% (Lake Rotoehu) of the samples. Health problems could result if more than 300 g of trout muscle tissue was consumed on a regular basis over an extended period. This study has demonstrated that the prevalence of freshwater cyanotoxin-producing cyanobacteria is widespread in New Zealand waterbodies and these cyanotoxins pose a potential health risk to both humans and animals either directly or indirectly.</p>

Rotifers weaken the efficiency of the cyanobacterium defence against ciliate grazers

ABSTRACT Cyanobacteria can protect themselves through limited dispersion and by increasing the compactness of the mucilage-covered cyanobacterial mat as well as by producing sheaths covering their trichomes. These features have been used in research to measure their degree of inducible defence. The influence of the presence of the rotifers Lecane inermis on the effectiveness of Phormidium sp. (Ph2) cyanobacterium defence was investigated. Experiments were conducted on the ciliates Pseudomicrothorax dubius and Furgasonia blochmanni, specialised in the ingestion of filamentous cyanobacteria. The most compact were cyanobacterial mats that were subjected exclusively to ciliates and the most dispersed were mats in the presence of rotifers alone. The presence of rotifers feeding on cyanobacterial mucilage led to the decreased effectiveness of the defence in two ways, by increasing the dispersion of cyanobacterial trichomes, thus loosening the cyanobacterial mat, and through the ingestion of the exopolysaccharide material covering the trichomes. As a result, in the presence of rotifers and the high density of ciliates, almost all the trichomes were removed. Moreover, in comparison with other treatments, a higher number of ciliates and rotifers remained active until the end of the experiments. This is the first report to show how rotifers can weaken the defence of cyanobacteria.

Controls on O2Production in Cyanobacterial Mats and Implications for Earth's Oxygenation

Cyanobacterial mats are widely assumed to have been globally significant hot spots of biogeochemistry and evolution during the Archean and Proterozoic, but little is known about their quantitative contributions to global primary productivity or Earth's oxygenation. Modern systems show that mat biogeochemistry is the outcome of concerted activities and intimate interactions between various microbial metabolisms. Emerging knowledge of the regulation of oxygenic and sulfide-driven anoxygenic photosynthesis by versatile cyanobacteria, and their interactions with sulfur-oxidizing bacteria and sulfate-reducing bacteria, highlights how ecological and geochemical processes can control O2production in cyanobacterial mats in unexpected ways. This review explores such biological controls on O2production. We argue that the intertwined effects of light availability, redox geochemistry, regulation and competition of microbial metabolisms, and biogeochemical feedbacks result in emergent properties of cyanobacterial mat communities that are all critical yet largely overlooked mechanisms to potentially explain the protracted nature of Earth's oxygenation.