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At least 163 records · Page 9Linked to original sources
PubMed2000

Galacturonic-acid-induced increase of superoxide production in red tide phytoplankton Chattonella marina and Heterosigma akashiwo.

Red tide phytoplankton, Chattonella marina and Heterosigma akashiwo, are known to generate superoxide anion (O2-). We found that galacturonic acid (GaLUA) stimulated C. marina and H. akashiwo to generate increased amounts of O2-. Since such effect was not observed in any other monosaccharides tested, our results suggest that the binding of GalUA to specific sites on the flagellate cell surface may induce the increase of 02- production.

Culture Media↗
PubMed2001

Bacterial resistance in urinary tract infections: how to stem the tide.

Each year, approximately 10% of the population is diagnosed with a urinary tract infection (UTI). Escherichia coli is the most prevalent pathogen in UTIs but other species make significant contributions. UTIs are commonly treated with antibiotics and, therefore, a potential source for the emergence and/or selection of resistant bacteria. Although susceptibility to some antibiotics for a number of species is still high, resistance is an issue both for community- and hospital-acquired UTI. However, often treatment is empiric, especially in the community setting. This empiric treatment is often guided by inadequate information about the (local) rates of resistance, selection and emergence of resistance, although there is a general consensus that there is a relationship between antibiotic use and resistance. It is well known that some antibiotics, e.g., some fluoroquinolones, are able to induce mutations leading to resistance but the antibiotics prescribed also affect the commensal flora, potentially selecting resistant organisms. However, antibiotics meant to treat other infections may select uropathogens and, thereby, the risk for UTIs increases. The duration of treatment of any infection is an important factor to consider in this respect, as well as subinhibitory concentrations of the antibiotic prescribed. Prudent use of new and still effective antibiotics is required. Although prudent use of these antibiotics may help to reduce the prevalence of antibiotic-resistant uropathogens, elimination will be hard to achieve. Therefore, we believe, that we can reduce the tide but we will still have to deal with the resistance problem in the future.

Anti-Bacterial Agents↗
PubMed2006

Concordance between short-term experiments and long-term censuses in tide pool fishes.

Sixteen years of annual censuses (1990-2005) of an assemblage of tide pool sculpins at Tatoosh Island, Washington, USA, revealed relative constancy in the numbers of recruits and adults. However, the dominant species as a recruit (Clinocottus globiceps) was always replaced numerically as an adult by another species (Oligocottus maculosus). When mechanisms of coexistence were evaluated, little support was found for either a lottery model, because competitive interactions are hierarchical, or a storage-effect model of coexistence, because the relative ranking of recruitment varied little among years and did not covary among species with environmental variables such as ocean temperature, upwelling indices, or an estimator of ocean productivity (oyster condition index). There was also little evidence of niche partitioning based on habitat affinities. Additionally, predation-mediated coexistence had little support, given that the competitive dominant did not have the greatest rates of mortality. Instead, a competition-colonization trade-off may contribute to the coexistence of these species, where C. globiceps always recruits in the greatest numbers, while O. maculosus dominates the adult assemblage via competitive processes. The importance of post-recruitment processes in this assemblage is further suggested by some negative associations among species, the presence of density dependence, some habitat affinities, and previously published experimental work that demonstrated the competitive dominance of O. maculosus over C globiceps.

Animals↗
PubMed2004

Aryloxy phosphoramidate triesters as pro-tides.

We herein describe the development of aryloxy phosphoramidate triesters as an effective pro-tide motif for the intracellular delivery of charged bio-active antiviral nucleoside monophosphates. The review covers the discovery of such aryl phosphoramidates, their mechanism of action and structure-activity relationships. The application of this strategy to a range of antiviral nucleosides is highlighted.

Amides↗
PubMed1977

An epizootic of waterfowl associated with a red tide episode in Florida.

During February and March, 1974, an epizootic involving lesser scaup (Aythya affinis) occurred in the Tampa Bay area on the west coast of Florida. Several thousand ducks are estimated to have died. Concurrent with this epizootic was a red tide caused by heavy blooms of the toxic dinoflagellate Gymnodinium breve intoxication were evident in some of the lesser scaup. A controlled experimental feeding of G. breve toxic material to White Pekin ducklings produced illness and death with signs comparable to some of those seen in the scaup.

Animals↗
PubMed1977

Growth response of the marine blue-green alga, Gomphosphaeria aponina, to inorganic nutrients and significance to management of Florida red tide.

A bioactive isolate from the blue-green alga Gomphosphaeria aponina is cytolytic towards the dinoflagellate, Gymnodinium breve, Florida's red tide organism. Batch and continuous cultures of G. aponina were used to determine nutrient limitation and to optimize mass-culture conditions. Iron and inorganic carbon were growth limiting; first-order saturation kinetics were observed for both substrates. For Fe3+, kinetic parameters were: Ks = 62 +/- 9 microgram 1(-1), and Ke max = 2.14 days-1. Maximum growth was observed at 150 micrograms Fe3+1(-1), with minimal growth below 10 microgram 1(-1). Cells colonized with increasing Fe3+ supplements, and time to reach maximum culture populations was inversely related to the concentration. For HCO3-,Ks = 62 +/- 4 mg1(-1) and Ke max = 1.3 day-1. Additions of NH4+ up to 200 micrograms 1(-1) were not stimulatory, whereas at 1.0 mg 1(-1) levels, Ke was 50% greater than for NO3- enriched medium. Concentrations greater than 25 micrograms PO4(3-) 1(-1) were stimulatory. However, at 1 mg1(-1), growth was less than in controls. Comparison of similar data available for G. breve would suggest that the inorganic nutrient requirements of G. aponina were minimal. Potential for natural control of G. breve by G. aponina is perhaps related to the efficiency of contact of the two organisms.

Animals↗
PubMed1976

Bad tidings and the hospitalized patient.

The physician in hospital practice may be faced with a situation in which a patient under his care suffers a bereavement or some other unexpected tragedy but is unaware of the fact. Three such cases encountered in the context of our psychiatric sonsultation service are presented. Factors influencing the decision as to whether, when and how the patient should be informed are considered. The complex psychodynamic situation which arises and involves the patient, his family and the medical staff is described. Stress is laid on the role played by archaic fears of being the bearer of evil tidings. The situation is seen as being ideally handled by the direct treating physician in conjunction with the family, the extent of psychiatric intervention being dictated by the needs of each of the parties concerned. Ideally the patient should be told as soon as his physical and mental condition are seen as conducive and preferably before he leave hospital.

Adult↗
PubMed2001

Critical micelle concentrations of allelopathic substances produced by Nannochloris oculata which affect a red tide organism, Gymnodinium breve.

Laboratory cultures of the green algae Nannochloris oculata and Nannochloris eucaryotum are known to cause lysis of Gymnodinium breve, which is Florida's red tide organism. Two cytolytic agents were previously identified as methyl palmitate and methyl stearate. In this study, the critical micelle concentrations of these substances were determined by ultraviolet light and turbidimetric methods to be 3.5 +/- 0.3 ppm (methyl stearate) and 4.3 +/- 0.6 (methyl palmitate). There were no significant differences in results obtained using the two methods.

Animals↗
PubMedDate not supplied

[Effect of variable phases of tide cycle on reproduction of Laomedea flexuosa (Hydroidea, Thecaphora].

Colonial hydroid Laomedea flexuosa inhabits the narrow belt of low littoral zone in the White Sea. What is a reason of so limited habitat? The authors studied the time of planulae release and its behavior during free swimming stages and settlement of larvae in nature and under laboratory conditions. Three methods were used to registrate the tidal dependent dynamic of planulae release: 1) plankton collecting bags around Fucus inflatus kelp with mature hydroids colonies; 2) active stirring kelps with hydroids in container with water, which is an old way to stimulate planulae release; 3) direct account of the mature planulae into gonangia. The dynamic of intensity of L. flexuosa planulae release was investigated according 3-4 phases of tidal cycle. All data were statistically tested. For L. flexuosa a moment of general larvae release was found in phase with the period of low water. This correlation could explain strict limitation in occurrence of L. flexuosa only in the lower part of intertidal zone. Laboratory experiments show that planulae release is stimulated by littoral drainage, and renewal of water movement during the beginning of tide. The decrease in time of planulae settlement is an affective way for marine sedentary species to stay in a narrow zone of optimal habitat.

Animals↗
PubMed2003

Turning the tide: preserving community mental health services.

As part of its continuing mission to serve trustees and staff of health foundations and corporate giving programs, Grantmakers In Health (GIH) convened a group of experts from the fields of philanthropy, research, government, and health care on September 19, 2002 to examine the status of community-based services for people with mental disorders. This Issue Dialogue, "Turning the Tide: Preserving Community Mental Health Services," explored how health grantmakers can support community programs that provide critical mental health intervention and treatment services to children and adults. This Issue Brief synthesizes key points from the day's discussion with a background paper previously prepared for Issue Dialogue participants. It includes quantitative and qualitative information on mental health, as well as profiles of public sector, private sector, and grantmaker strategies for promoting improvements.

Adolescent↗
PubMed2003

[Distribution features of chlorophyll a and primary productivity in high frequency area of red tide in East China Sea during spring].

The distributions of chlorophyll a and primary productivity were determined during April to May 2002 in the East China Sea. The results showed that the average concentration of chlorophyll a was 1.086 mg.m-3 at surface layer, and that nano- and pico-phytoplankton (< 20 microns) dominated the phytoplankton biomass in this sea region during Spring (up to 64% of total chlorophyll a content). Ultra-phytoplankton (< 5 microns) consisted 27% of total phytoplankton biomass. Nutrients and feeding pressure of zooplankton affected the distribution of chlorophyll a and its size-fractionation. The average primary productivity was 10.091 mg.m-3.h-1, while that of red tide tracking stations R-03, RL-01 and RG-01 was 399.984 mg.m-3.h-1. Light and nutrients were the main factors affecting the distributions of chlorophyll a and primary productivity. The station DC-11 had a high concentration of phytoplankton biomass. The surface layer concentration of chlorophyll a and primary productivity were up to 9,082 mg.m-3 and 128,79 mg.m-3.h-1, respectively, but the color of the seawater was normal.

Animals↗
PubMed2003

[Distribution of phytoplankton and water dynamical environmental factors in high red tide occurrence area of Changjiang River estuary].

Species composition and cell abundance of phytoplankton, and its relations with environmental factors were investigated in the Changjiang River estuary of east China sea (30 degrees 50'-31 degrees 50'N, 121 degrees 50'-123 degrees 00'E). A total of 110 taxa belonging to 45 genera of phytoplankton in the investigation area were identified. The main species of phytoplankton resulted in red tide were Skeletonema costatum and Prorocentrum dentatum, etc. Phytoplankton abundance in the day was higher than that at night. The vertical distribution of phytoplankton in different water bodies was not obvious. The ecological groups of phytoplankton were freshwater group, estuarine and brackish water and low salinity group in the coast, high salinity and warm water group in off-sea, and widely ranging group. The abundance of phytoplankton in the Changjiang River estuary was 1.6 x 10(3)-75.2 x 10(3) ind.dm-3. The species composition and cell abundance of phytoplankton were related to the freshwater pouring into the Changjiang River estuary. The three waters in the area affecting the distribution of phytoplankton were the Changjiang River estuary water, freshwater, and warm water from outsea.

Ecosystem↗
PubMed2003

[Povidone-iodine and isothiozolone for removing red tide algae Phaeoecystis globosa].

Studies on the removal and control of red tide algae Phaeoecystis globosa by povidone-iodine and isothiozolone algaecide showed that Phaeoecystis globosa could be killed and controlled by povidone-iodine and isothiozolone. The effective concentration of povidone-iodine was 30 mg.L-1, and that of isothiozolone was 0.30 mg.L-1. Using povidone-iodine and isothiozolone together could improve the effect, and the ideal composite ratio of povidone-iodine and isothiozolone was 1.0:0.15.

Eukaryota↗
PubMed2004

[Removal of red tide organisms by organo-modified bentonite].

A series of organo-bentonites were synthesized by exchanging cation surfactants such as cyltrimethylammonium bromide and cetyltrimethylammonium to remove red tide organisms Skeletonema costatum. The results showed that the removal rate of Skeletonema costatum by the bentonites was in the order of cyltrimethylammonium surfactant modified iron pillared bentonite > cetyltrimethylammoium surfactant modified iron pillared bentonite > iron pillared bentonite > cyltrimethylammonium surfactant modified sodium bentonite > cetyltrimethylammoium surfactant modified > sodium bentonite. The removal rate of Skeletonema costatum was related to the length of alkyl chains and the amount of cation surfactants exchanged on bentonites.

Animals↗
PubMed2001

[Red tide bloom produced by Lingulodinium polyedrum (Peridiniales, Dinophyceae) in Bahía Culebra, Papagayo Gulf, Costa Rica].

This is the first record of the dinoflagellate Lingulodinium polyedrum in a red tide bloom in the North Pacific coast of Costa Rica. The sample was collected on April 2000 at Culebra Bay, Gulf of Papagayo, from a patch of aproximatly 2000 m2, which produced a red discoloration of the water and a peculiar strong odor. This species produces spherical hypnocysts that may remain for decades when dark or anoxic conditions are present; L. polyedrum had been associated with the production of paralyzing toxins such as saxitoxins and yessotoxins. A second smaller patch was observed close Panama beach, into the bay, where we found seven puffer fish (Diodontidae) and two lobsters dead in the sand. It is important to develop a monitoring program to identify seasonal behavior of this species and ameliorate its impact on coastal human communities.

Animals↗
PubMed2004

Axenic culture of Gyrodinium impudicum strain KG03, a marine red-tide microalga that produces exopolysaccharide.

An exopolysaccharide-producing microalgal dinoflagellate was isolated from a red-tide bloom and designated strain KG03. A bacteria-free culture of strain KG03 was achieved using a modified wash with phototaxis and antibiotic treatment. Combined treatment with neomycin and cephalosporin was the most effective for eliminating the bacteria associated with the microalgae. Strain KG03 was identified as Gyrodinium impudicum by analyzing the ITS regions of the 5.8S rDNA, 18S rDNA, morphological phenotype and fatty acid composition. The exopolysaccharide production and cell growth in a 300-ml photobioreactor were increased 2.7- and 2.4-fold, respectively, compared with that in a flask culture at the first isolation step.

Animals↗
PubMed1979

Uptake of iron by Gomphosphaeria aponina, a possible control organism for the Florida red tide Pytochodiscus brevis.

The assimilation of iron, a growth-limiting metal ion of the cytotoxic marine cyanobacterium, Gomphosphaeria aponina, has been examined in both static and steady-state cultures using 59Fe (III). Uptake of iron by cells followed first-order kinetics, and biphasic (absorption and uptake) behavior was observed as suggested by noted differences between cultures incubated in the light and in the dark. Iron removal in illuminated cultures was rapid, occurring at rates comparable to exponential growth rates. Although uptake was mediated by a chelating agent (EDTA), synthesis and iron assisted transport by hydroxamate-type siderophores was not involved in the uptake of iron by cells, as determined by standard chemical and biological assays of iron deficient cultures. The ecological implications of this research is considered with respect to the cytotoxic antagonism between the cyanobacterium and Florida's red tide organism, Pytochodiscus brevis (Gymnodinium breve).

Biological Transport↗
PubMed1984

Depolarizing action of a red-tide dinoflagellate brevetoxin on axonal membranes.

The neurotoxic actions of T17 , a toxin isolated from the red-tide dinoflagellate Ptychodiscus brevis, on membrane excitability were investigated by the intracellular microelectrode technique on the crayfish giant axons and by the voltage clamp experiments on the squid giant axons. External application of T17 toxin caused a concentration-dependent depolarization, transient repetitive discharges, followed by depression of the action potential leading to a complete block of excitability. The reversibility of the depolarizing action upon washing decreased as the time of toxin treatment was increased. The T17 -induced depolarization was effectively reversed by 0.3 microM tetrodotoxin or 1 mM Na external solution. Pretreatment with tetrodotoxin completely antagonized the T17 depolarizing action. However, upon washing the axon with the normal external solution, depolarization occurred. Pretreatment with either procaine or dibucaine at high doses also offered protection against the depolarization. The toxin action was greatly potentiated by the sea anemone toxin, anthopleurin-A. The voltage clamp experiments showed that T17 toxin affected sodium current only. The activation voltage for sodium current was shifted in the hyperpolarizing direction by more than 35 mV. T17 toxin also greatly depressed the fast inactivation of sodium current. However, there was no significant change in the kinetics of the sodium tail current. These results indicate that T17 toxin depolarizes the membrane by selectively opening sodium channels at fairly negative potentials and by inhibiting the fast sodium inactivation. We also infer that the binding site for T17 toxin is different from those for tetrodotoxin and sea anemone toxin.

Anesthetics, Local↗