Toxin Dynamics among Populations of the Bioluminescent HAB Species from the Indian River Lagoon, FL.

Dinoflagellate species that form some of the most frequent toxic blooms are also bioluminescent, yet the two traits are rarely linked when studying bloom development and persistence. is a toxic, bioluminescent dinoflagellate that previously bloomed in Florida with no known record of saxitoxin (STX) production. Over the past 20 years, STX was identified in populations.

Linking Copper-Associated Signal Transduction Systems with Their Environment in Marine Bacteria.

Copper is an essential trace element for living cells. However, copper can be potentially toxic for bacterial cells when it is present in excess amounts due to its redox potential. Due to its biocidal properties, copper is prevalent in marine systems due to its use in antifouling paints and as an algaecide.

Development of a real-time quantitative PCR assay for detection and quantification of the marine bacterium Alteromonas macleodii from coastal environments.

Alteromonas macleodii is a ubiquitous marine bacterial species found in a variety of habitats that displays both planktonic and particle-associated lifestyles. Transcriptomic studies demonstrate that, even when present at low abundance, it can make significant contributions to biogeochemical cycles, and its specific association with key marine phytoplankton species indicates other ecological roles as well. It has also been shown to be one of the early colonizers of copper-treated marine vessels.

Enhanced copper-resistance gene repertoire in Alteromonas macleodii strains isolated from copper-treated marine coatings.

Copper is prevalent in coastal ecosystems due to its use as an algaecide and as an anti-fouling agent on ship hulls. Alteromonas spp. have previously been shown to be some of the early colonizers of copper-based anti-fouling paint but little is known about the mechanisms they use to overcome this initial copper challenge.

and Genotypes Occur Together within Natural Sub-Populations from the Western Atlantic.

Saxitoxin (STX) is a secondary metabolite and potent neurotoxin produced by several genera of harmful algal bloom (HAB) marine dinoflagellates. The basis for variability in STX production within natural bloom populations is undefined as both toxic and non-toxic strains (of the same species) have been isolated from the same geographic locations. is a STX-producing bioluminescent dinoflagellate that blooms along the east coast of Florida as well as the bioluminescent bays in Puerto Rico (PR), though no toxicity reports exist for PR populations.

Bioluminescence and toxicity as driving factors in harmful algal blooms: Ecological functions and genetic variability.

Dinoflagellates are an ecologically important group of marine microbial eukaryotes with a remarkable array of adaptive strategies. It is ironic that two of the traits for which dinoflagellates are best known, toxin production and bioluminescence, are rarely linked when considering the ecological significance of either. Although dinoflagellate species that form some of the most widespread and frequent harmful algal blooms (HABs) are bioluminescent, the molecular and eco-evolutionary associations between these two traits has received little attention.

Multiple Megaplasmids Confer Extremely High Levels of Metal Tolerance in Strains.

is a widely distributed genus of marine , with representatives shown to be key players in diverse processes, including biogeochemical cycling and biofouling of marine substrata. While spp. are early colonizers of copper-based antifouling paints on marine vessels, their mechanism of tolerance is poorly understood.

Gene Expression Changes in Long-Term In Vitro Human Blood-Brain Barrier Models and Their Dependence on a Transwell Scaffold Material.

Disruption of the blood-brain barrier (BBB) is the hallmark of many neurovascular disorders, making it a critically important focus for therapeutic options. However, testing the effects of either drugs or pathological agents is difficult due to the potentially damaging consequences of altering the normal brain microenvironment. Recently, in vitro coculture tissue models have been developed as an alternative to animal testing.

Adaptation to copper stress influences biofilm formation in Alteromonas macleodii.

An Alteromonas macleodii strain was isolated from copper-containing coupons incubated in surface seawater (Key West, FL, USA). In addition to the original isolate, a copper-adapted mutant was created and maintained with 0.78 mM Cu.

Draft Genome Sequences of Four Alteromonas macleodii Strains Isolated from Copper Coupons and Grown Long-Term at Elevated Copper Levels.

Alteromonas macleodii is a marine bacterium involved in the early stages of biofouling on ship hulls treated with copper as an antifouling agent. We report here the draft genome sequences of an A. macleodii strain isolated from copper coupons and three laboratory mutants grown long-term at elevated copper levels.

Molecular Mechanisms Contributing to the Growth and Physiology of an Extremophile Cultured with Dielectric Heating.

Unlabelled: The effect of microwave frequency electromagnetic fields on living microorganisms is an active and highly contested area of research. One of the major drawbacks to using mesophilic organisms to study microwave radiation effects is the unavoidable heating of the organism, which has limited the scale (<5 ml) and duration (<1 h) of experiments. However, the negative effects of heating a mesophile can be mitigated by employing thermophiles (organisms able to grow at temperatures of >60°C).

Differences in Physical and Biochemical Properties of Thermus scotoductus SA-01 Cultured with Dielectric or Convection Heating.

A thermophile, Thermus scotoductus SA-01, was cultured within a constant-temperature (65°C) microwave (MW) digester to determine if MW-specific effects influenced the growth and physiology of the organism. As a control, T. scotoductus cells were also cultured using convection heating at the same temperature as the MW studies.

Selection and Evaluation of Reference Genes for Reverse Transcription-Quantitative PCR Expression Studies in a Thermophilic Bacterium Grown under Different Culture Conditions.

The phylum Deinococcus-Thermus is a deeply-branching lineage of bacteria widely recognized as one of the most extremophilic. Members of the Thermus genus are of major interest due to both their bioremediation and biotechnology potentials. However, the molecular mechanisms associated with these key metabolic pathways remain unknown.

Suppressing the Neurospora crassa circadian clock while maintaining light responsiveness in continuous stirred tank reactors.

Neurospora crassa has been utilized as a model organism for studying biological, regulatory, and circadian rhythms for over 50 years. These circadian cycles are driven at the molecular level by gene transcription events to prepare for environmental changes. N.

Selection and evaluation of reference genes for expression studies with quantitative PCR in the model fungus Neurospora crassa under different environmental conditions in continuous culture.

Neurospora crassa has served as a model organism for studying circadian pathways and more recently has gained attention in the biofuel industry due to its enhanced capacity for cellulase production. However, in order to optimize N. crassa for biotechnological applications, metabolic pathways during growth under different environmental conditions must be addressed.

An overview on the marine neurotoxin, saxitoxin: genetics, molecular targets, methods of detection and ecological functions.

Marine neurotoxins are natural products produced by phytoplankton and select species of invertebrates and fish. These compounds interact with voltage-gated sodium, potassium and calcium channels and modulate the flux of these ions into various cell types. This review provides a summary of marine neurotoxins, including their structures, molecular targets and pharmacologies.

Paralytic shellfish toxins inhibit copper uptake in Chlamydomonas reinhardtii.

Paralytic shellfish toxins are secondary metabolites produced by several species of dinoflagellates and cyanobacteria. Known targets of these toxins, which typically occur at detrimental concentrations during harmful algal blooms, include voltage-gated ion channels in humans and other mammals. However, the effects of the toxins on the co-occurring phytoplankton community remain unknown.

Inhibition of copper uptake in yeast reveals the copper transporter Ctr1p as a potential molecular target of saxitoxin.

Saxitoxin is a secondary metabolite produced by several species of dinoflagellates and cyanobacteria which targets voltage-gated sodium and potassium channels in higher vertebrates. However, its molecular target in planktonic aquatic community members that co-occur with the toxin producers remains unknown. Previous microarray analysis with yeast identified copper and iron-homeostasis genes as being differentially regulated in response to saxitoxin.

Perturbation of FliL interferes with Proteus mirabilis swarmer cell gene expression and differentiation.

Proteus mirabilis is a dimorphic, motile bacterium often associated with urinary tract infections. Colonization of urinary tract surfaces is aided by swarmer cell differentiation, which is initiated by inhibition of flagellar rotation when the bacteria first contact a surface. Mutations in fliL, encoding a flagellar structural protein with an enigmatic function, result in the inappropriate production of differentiated swarmer cells, called pseudoswarmer cells, under noninducing conditions, indicating involvement of FliL in the surface sensing pathway.

Sphaerochaeta globosa gen. nov., sp. nov. and Sphaerochaeta pleomorpha sp. nov., free-living, spherical spirochaetes.

Free-living bacteria with spherical cells 0.5-2.5 µm in diameter were isolated from freshwater sediment.

Transcriptional profiling of Saccharomyces cerevisiae upon exposure to saxitoxin.

Saxitoxin is a potent neurotoxin produced by several species of dinoflagellates and cyanobacteria. The molecular target of saxitoxin in higher eukaryotes is the voltage-gated sodium channel; however, its target in lower eukaryotic organisms remains unknown. The goal of this study was to obtain the transcriptional fingerprint of the model lower eukaryote Saccharomyces cerevisiae upon exposure to saxitoxin to identify potential genes suitable for biomarker development.