Oxygen supply by photosynthesis to an implantable islet cell device.

Transplantation of islet cells is an effective treatment for type 1 diabetes with critically labile metabolic control. However, during islet isolation, blood supply is disrupted, and the transport of nutrients/metabolites to and from the islet cells occurs entirely by diffusion. Adequate oxygen supply is essential for function/survival of islet cells and is the limiting factor for graft integrity.

Repellency of naturally occurring volatile alcohols to fungus gnat Bradysia sp. nr. coprophila (Diptera: Sciaridae) adults under laboratory conditions.

This study, conducted under laboratory conditions, was designed to determine the repellent activity of 10 naturally occurring volatile alcohol constituents against adults of the fungus gnat, Bradysia sp. nr. coprophila (Lintner) (Diptera: Sciaridae).

Photosynthesis of Prochlorothrix hollandica under Sulfide-Rich Anoxic Conditions.

The photosynthetic activity and photosystem II fluorescence of Prochlorothrix hollandica were studied under anoxic, sulfide-rich conditions. Oxygenic photosynthetic activity with water as the electron donor was highly resistant to inhibition by sulfide. Cells still retained 50% of their oxygenic photosynthetic activity at >1 mM sulfide.

Nutritional and lifestyle habits and water-fiber interaction in colorectal adenoma etiology.

Adenomatous polyps are neoplasms that may progress to colorectal cancer. The role of diet and other lifestyle habits in their etiology is now being elucidated. The aim of this study was to evaluate effects of nutritional habits, weight and weight gain, tobacco smoking, and physical activity in adenoma etiology.

Evaluation of Cyanothece sp. ATCC 51142 as a candidate for inclusion in a CELSS.

Controlled ecological life support systems (CELSS) have been proposed to make long-duration manned space flights more cost-effective. Higher plants will presumably provide food and a breathable atmosphere for the crew. It has been suggested that imbalances between the CO2/O2 gas exchange ratios of the heterotrophic and autotrophic components of the system will inevitably lead to an unstable system, and the loss of O2 from the atmosphere.

Potential contribution of the diazotrophic cyanobacterium, Cyanothece sp. strain 51142, to a bioregenerative life support system.

Long-duration manned space missions will likely require the development of bioregenerative means of life support. Such a Controlled Ecological Life Support System (CELSS) would use higher plants to provide food and a breathable atmosphere for the crew and employ a waste processing system to recover elements for recycling. The current study identifies ways in which a cyanobacterial component may enhance the sustainability of a space-deployed CELSS, including balancing CO2/O2 gas exchange, production of bioavailable N, dietary supplementation, and contingency against catastrophic failure of the higher plant crops.

Compositional and toxicological evaluation of the diazotrophic cyanobacterium, Cyanothece sp. strain ATCC 51142.

Compositional analyses of Cyanothece sp. strain ATCC 51142 showed high protein (50-60%) and low fat (0.4-1%) content, and the ability to synthesize vitamin B12.

Purification and characterization of sulfide-quinone reductase, a novel enzyme driving anoxygenic photosynthesis in Oscillatoria limnetica.

An enzyme catalyzing sulfide quinone oxido-reduction (E.C.1.

Sulfide quinone reductase (SQR) activity in Chlorobium.

Membranes of the green sulfur bacterium, Chlorobium limicola f. thiosulfatophilum, catalyze the reduction of externally added isoprenoid quinones by sulfide. This activity is highly sensitive to stigmatellin and aurachins.

Sulfide-induced sulfide-quinone reductase activity in thylakoids of Oscillatoria limnetica.

Sulfide-dependent partial electron-transport reactions were studied in thylakoids isolated from cells of the cyanobacterium Oscillatoria limnetica, which had been induced to perform sulfide-driven anoxygenic photosynthesis. It was found that these thylakoids have the capacity to catalyze electron transfer, from sulfide to externally added quinones, in the dark. Assay conditions were developed to measure the reaction either as quinone-dependent sulfide oxidation (colorimetrically) or as sulfide-dependent quinone reduction (by UV dual-wavelength spectrophotometry).

Sulfide induction of synthesis of a periplasmic protein in the cyanobacterium Oscillatoria limnetica.

Two proteins which may play a role in the induction of anoxygenic photosynthesis in Oscillatoria limnetica have been demonstrated by comparing the pattern of labeling during pulses of [35S]methionine of cells incubated under inducing conditions [anaerobic conditions plus 3-(3,4-dichlorophenyl)-1,1-dimethylurea, light, and sulfide) with that of cells incubated under noninducing conditions (without sulfide). The major inducible protein has an apparent molecular mass of 11.5 kilodaltons and is associated with a less strongly labeled 12.

Sulfur metabolism in Beggiatoa alba.

The metabolism of sulfide, sulfur, and acetate by Beggiatoa alba was investigated under oxic and anoxic conditions. B. alba oxidized acetate to carbon dioxide with the stoichiometric reduction of oxygen to water.

Sulfide-dependent photosynthetic electron flow coupled to proton translocation in thylakoids of the cyanobacterium Oscillatoria limnetica.

Light-induced proton translocation coupled to sulfide-dependent electron transport has been studied in isolated thylakoids of the cyanobacterium Oscillatoria limnetica. The thylakoids are obtained by osmotic shock of washed spheroplasts, prepared with glycine-betaine as the osmotic stabilizer. 13C NMR studies suggests that betaine is the major osmoregulator in O.

Energy in avian eggs and hatchlings: utilization and transfer.

Energy content of eggs, hatchlings, and egg components (albumen, yolk, true hatchling = hatchling without spare yolk, and spare yolk) and the energy spent for metabolism were analyzed in 50 species of birds divided into four maturity types. Mass-specific energy density on the basis of fresh egg content mass appears to be mass-independent within each maturity group but different among the groups. Mass-specific energy densities calculated on the basis of dry component mass are the same for albumen, yolk, and spare yolk in all maturity groups but are different for true hatchlings, precocial hatchlings being richer in energy than all others.