From our experimental evidence that iron lirnitation greatly increases the extracellular concentration of strong copper-complexing agents in cultures of Anabaena flos-aquae and Anabaena cyhdrica, and that the iron-algal exudate complex is much more stable than the copper complex, we conclude that strong copper-complexing agents released by filamentous blue-green algae are siderophores. Further ...

Z. Naturforsch. 46c, 542-548 (1991); received February 13, 1991 Blue-Light Photoreceptor, Chlorophyll Synthesis, Desmarestia aculeata, Green-Light Photo­ receptor, Nitrate The chlorophyll synthesis in the brown algae Desmarestia aculeata is affected by light quali­ ty and by the nutrient state in the medium before the illumination. Pulses of 5 min of red, green and blue light together with 200 ...

Bathing in the Blue Lagoon, a specific geothermal biotope in Iceland has been known for many years to be beneficial for human skin in general and for patients with psoriasis and atopic dermatitis in particular. The scientific rationale for this empirical observation, however has remained elusive. We now report that extracts prepared from silica mud and two different microalgae species derived f...

As human populations increase and land-use intensifies, toxic and unsightly nuisance blooms of algae are becoming larger and more frequent in freshwater lakes. In most cases, the blooms are predominantly blue-green algae (Cyanobacteria), which are favored by low ratios of nitrogen to phosphorus. In the past half century, aquatic scientists have devoted much effort to understanding the causes of...

Algae green, blue–green, and diatom grown in inorganic media produced particulate and dissolved organic carbon DOC . DOC produced by a green-alga contains 25% hydrophobic acids. DOC from all algae had specific ultraviolet absorbance values less than 2.0 m−1 mg/L −1. Algae-produced DOC was biologically labile; greater than 60% degraded in bioreactors within 5 days. The biodegradable material lik...

The relationship of insect predators and phytoplankton with the abundance of Culex tritaeniorhynchus Giles, Cx. vishnui Theobald and Cx. pseudovishnui Colless mosquito larvae and pupae (Diptera: Culicidae) in ricefields was investigated during three rice growing seasons. Notonectids were the most abundant insect predators, whereas diatoms dominated among phytoplankton. Multiple regression analy...

A batch anaerobic test was conducted to evaluate the effects of adding high carbon content of corn straw to the digestion of Taihu blue algae to attain an optimal C/N ratio for higher methane yield. The addition of corn straw in algae at a C/N ratio of 20/1 increased methane yield by 61.69% at 325 mL g(-1)VS(-1) (compared with 201 mL g(-1) VS(-1) of algae digestion alone), followed by C/N ratio...

Four obligately photoautotrophic blue-green algae were shown to assimilate acetate. This reaction was light dependent and was greatly decreased in the absence of carbon dioxide. Acetate was incorporated mainly into the ethanol extractable (lipid) fraction of the organisms and into the protein fraction. Only four amino acids (glutamate, proline, arginine, leucine) were significantly radioactive ...

Culture conditions are described under which Cyanophora paradoxa grows with a generation time of less than two days. The organism is an obligate photoautotrophic flagellate unable to degrade exogenous carbohydrates via respiration. It does not synthesize nitrogenase but can form a hydrogenase with similar properties as in blue-green algae. The photosynthetic 0 2-evolution pro­ ceeds with essent...

Spherical bodies resembling coccidian oocysts and measuring 8.0 to 9.0 microns in diameter were seen in the stools of eight persons with explosive, watery diarrhea. Seven had recently traveled to tropical countries, mostly in the Caribbean, and four had acquired immunodeficiency syndrome. The structures were easily discernible in wet mounts by light microscopy and contained variable numbers of ...