A critical review of the postulated role of the non-essential amino acid, β-N-methylamino-L-alanine, in neurodegenerative disease in humans.

The compound BMAA (β-N-methylamino-L-alanine) has been postulated to play a significant role in four serious neurological human diseases: Amyotrophic Lateral Sclerosis/Parkinsonism Dementia Complex (ALS/PDC) found on Guam, and ALS, Parkinsonism, and dementia that occur globally. ALS/PDC with symptoms of all three diseases first came to the attention of the scientific community during and after World War II. It was initially associated with cycad flour used for food because BMAA is a product of symbiotic cycad root-dwelling cyanobacteria.

A bioengineering system for in situ bioremediation of contaminated groundwater.

Much of the past and current focus of bioremediation has been on laboratory studies of microbial processes. By necessity, early studies have ignored important field properties, parameters, and processes that control the ultimate success of in situ bioremediation of contaminated groundwater. This paper presents a bioengineering systems approach that examines the impact of some of these field variables on common bioremediation practices.

Biosorption of uranium by Pseudomonas aeruginosa strain CSU: characterization and comparison studies.

Pseudomonas aeruginosa strain CSU, a nongenetically engineered bacterial strain known to bind dissolved hexavalent uranium (as UO(2) (2+) and/or its cationic hydroxo complexes), was characterized with respect to its sorptive activity (equilibrium and dynamics). Living, heat-killed, permeabilized, and unreconstituted lyophilized cells were all capable of binding uranium. The uranium biosorption equilibrium could be described by the Langmuir isotherm.

Degradation of organic sulfur compounds by a coal-solubilizing fungus.

Paecilomyces sp. TLi, a coal-solubilizing fungus, was shown to degrade organic sulfur-containing coal substructure compounds. Dibenzothiophene was degraded via a sulfur-oxidizing pathway to 2,2'-dihydroxybiphenyl.

Binding of Dissolved Strontium by Micrococcus luteus.

Resting cells of Micrococcus luteus have been shown to remove strontium (Sr) from dilute aqueous solutions of SrCl(2) at pH 7. Loadings of 25 mg of Sr per g of cell dry weight were achieved by cells exposed to a solution containing 50 ppm (mg/liter) of Sr. Sr binding occurred in the absence of nutrients and did not require metabolic activity.

Role of Veratryl Alcohol in Regulating Ligninase Activity in Phanerochaete chrysosporium.

Ligninase activity in Phanerochaete chrysosporium is stimulated by incubating cultures with various substrates for the enzyme, including veratryl (3,4-dimethoxybenzyl) alcohol, which is a secondary metabolite of this fungus. This study was designed to provide insight into the mechanism involved in this stimulation. Ligninase activity increased 2 to 4 h after the addition of exogenous veratryl alcohol to ligninolytic cultures.

Factors Involved in the Regulation of a Ligninase Activity in Phanerochaete chrysosporium.

The regulation of an H(2)O(2)-dependent ligninolytic activity was examined in the wood decay fungus Phanerochaete chrysosporium. The ligninase appears in cultures upon limitation for nitrogen or carbohydrate and is suppressed by excess nutrients, by cycloheximide, or by culture agitation. Activity is increased by idiophasic exposure of cultures to 100% O(2).

Biochemistry of the oxidation of lignin by Phanerochaete chrysosporium.

The objective of this research was to identify the biochemical agents responsible for the oxidative degradation of lignin by the white-rot fungus Phanerochaete chrysosporium. We examined the hypothesis that activated oxygen species are involved, and we also sought the agent in ligninolytic cultures responsible for a specific oxidative degradative reaction in substructure model compounds. Results of studies of the production of activated oxygen species by cultures, of the effect of their removal on ligninolytic activity, and of their action on substructure model compounds support a role for hydrogen peroxide (H(2)O(2)) and possibly superoxide (O(2)(*)(-)) in lignin degradation.

Relationship Between Lignin Degradation and Production of Reduced Oxygen Species by Phanerochaete chrysosporium.

The relationship between the production of reduced oxygen species, hydrogen peroxide (H(2)O(2)), superoxide (O(2)), and hydroxyl radical (.OH), and the oxidation of synthetic lignin to CO(2) was studied in whole cultures of the white-rot fungus Phanerochaete chrysosporium Burds. The kinetics of the synthesis of H(2)O(2) coincided with the appearance of the ligninolytic system; also, H(2)O(2) production was markedly enhanced by growth under 100% O(2), mimicking the increase in ligninolytic activity characteristic of cultures grown under elevated oxygen tension.