Effects of warming and eutrophication on coastal phytoplankton production.

Phytoplankton production in coastal waters influences seafood production and human health and can lead to harmful algal blooms. Water temperature and eutrophication are critical factors affecting phytoplankton production, although the combined effects of warming and nutrient changes on phytoplankton production in coastal waters are not well understood. To address this, phytoplankton production changes in natural waters were investigated using samples collected over eight months, and under 64 different initial conditions, established by combining four different water temperatures (i.

Effects of light intensity, temperature, and salinity on the growth and ingestion rates of the red-tide mixotrophic dinoflagellate Paragymnodinium shiwhaense.

Among mixotrophic dinoflagellates, the maximum mixotrophic growth rate of the red-tide dinoflagellate Paragymnodinium shiwhaense is relatively high, whereas mortality due to predation is low. To investigate the effects of major environmental parameters on P. shiwhaense, growth and ingestion rates of one strain of P.

Islandinium minutum subsp. barbatum subsp. nov. (Dinoflagellata), a New Organic-Walled Dinoflagellate Cyst from the Western Arctic: Morphology, Phylogenetic Position Based on SSU rDNA and LSU rDNA, and Distribution.

A study of modern sediment from the Western Arctic has revealed the presence of a distinctive brown-colored cyst with a spherical central body bearing unbranched processes that are usually solid with a small basal pericoel. Distinctive barbs project from some processes, and process tips are usually minutely expanded into conjoined barbs. The archeopyle is apical and saphopylic.

Structure Elucidation and in Vitro Toxicity of New Azaspiracids Isolated from the Marine Dinoflagellate Azadinium poporum.

Two strains of Azadinium poporum, one from the Korean West coast and the other from the North Sea, were mass cultured for isolation of new azaspiracids. Approximately 0.9 mg of pure AZA-36 (1) and 1.

Gymnodinium smaydae n. sp., a new planktonic phototrophic dinoflagellate from the coastal waters of Western Korea: morphology and molecular characterization.

The marine phototrophic dinoflagellate Gymnodinium smaydae n. sp. is described from cells prepared for light, scanning, and transmission electron microscopy.

Cyst-theca relationship of the arctic dinoflagellate cyst Islandinium minutum (Dinophyceae) and phylogenetic position based on SSU rDNA and LSU rDNA.

Round brown spiny cysts constitute a morphological group common in high latitude dinoflagellate cyst assemblages. The dinoflagellate cyst Islandinium minutum (Harland et Reid) Head, Harland et Matthiessen is the main paleoecological indicator of seasonal sea-ice cover in the Arctic. Despite the importance of this cyst in paleoceanographical studies, its biological affinity has so far been unknown.

New azaspiracids in Amphidomataceae (Dinophyceae).

Azaspiracids (AZAs) are a group of lipophilic polyether toxins implicated in incidents of shellfish poisoning in humans, particularly in northern Europe, which are produced by the small marine dinoflagellate Azadinium spinosum. Other related species/strains of the Amphidomataceae have not been proven to date to contain any of the known azaspiracids. Closer analyses of these species/strains by triple quadrupole mass spectrometry in the precursor and product ion mode now revealed four new compounds with high similarity to azaspiracids, all of them with a characteristic m/z 348 fragment but with absence of the m/z 362 fragment.

First report of the photosynthetic dinoflagellate genus Azadinium in the Pacific Ocean: morphology and molecular characterization of Azadinium cf. poporum.

A strain of a dinoflagellate belonging to the genus Azadinium was obtained by the incubation of sediments collected from Shiwha Bay, Korea. This report of the genus Azadinium is the first outside of northern Europe and furthermore from the Pacific Ocean. The diagnostic morphological features of the isolate very closely resemble the recently described species Azadinium poporum isolated from the North Sea.

Cooperative action of multiple cis-acting elements is required for N-myc expression in branchial arches: specific contribution of GATA3.

The precise expression of the N-myc proto-oncogene is essential for normal mammalian development, whereas altered N-myc gene regulation is known to be a determinant factor in tumor formation. Using transgenic mouse embryos, we show that N-myc sequences from kb -8.7 to kb +7.

Proteomic, microarray, and signature-tagged mutagenesis analyses of anaerobic Pseudomonas aeruginosa at pH 6.5, likely representing chronic, late-stage cystic fibrosis airway conditions.

Patients suffering from cystic fibrosis (CF) commonly harbor the important pathogen Pseudomonas aeruginosa in their airways. During chronic late-stage CF, P. aeruginosa is known to grow under reduced oxygen tension and is even capable of respiring anaerobically within the thickened airway mucus, at a pH of approximately 6.

Sigma factors in Pseudomonas aeruginosa.

In Pseudomonas aeruginosa, as in most bacterial species, the expression of genes is tightly controlled by a repertoire of transcriptional regulators, particularly the so-called sigma (sigma) factors. The basic understanding of these proteins in bacteria has initially been described in Escherichia coli where seven sigma factors are involved in core RNA polymerase interactions and promoter recognition. Now, 7 years have passed since the completion of the first genome sequence of the opportunistic pathogen P.

Comparative signature-tagged mutagenesis identifies Pseudomonas factors conferring resistance to the pulmonary collectin SP-A.

The pulmonary collectin, surfactant protein A (SP-A), is a broad spectrum opsonin with microbicidal membrane permeabilization properties that plays a role in the innate immune response of the lung. However, the factors that govern SP-A's microbial specificity and the mechanisms by which it mediates membrane permeabilization and opsonization are not fully understood. In an effort to identify bacterial factors that confer susceptibility or resistance to SP-A, we used comparative signature-tagged mutagenesis to screen a library of 1,680 Pseudomonas aeruginosa mutants for evidence of differential pulmonary clearance in SP-A-sufficient (SP-A) and SP-A-deficient (SP-A) mice.

Identification of novel pathogenicity genes by PCR signature-tagged mutagenesis and related technologies.

Microbial pathogens possess a repertoire of virulence determinants that make unique contributions to bacterial fitness during infection. In this chapter, we focus on the recent progress and adaptations of signature-tagged mutagenesis (STM) by PCR instead of hybridization. This is a PCR-based STM mutation-based screening method using a population of bacterial mutants for the simultaneous identification of multiple virulence genes in microbial pathogens by negative selection.

In vivo functional genomics of Pseudomonas aeruginosa for high-throughput screening of new virulence factors and antibacterial targets.

Pseudomonas aeruginosa is a model for studying opportunistic pathogens that are highly resistant to most classes of antibiotics and cause chronic pulmonary infections. We have developed and adapted a multiplex polymerase chain reaction-based signature-tagged mutagenesis (STM) for high-throughput screening of a collection of 7968 P. aeruginosa mutants in a rat model of chronic respiratory infection.