The ultrastructure of sectioned cells of mutant and wild type Rhodopseudomonas spheroides has been examined by electron microscopy. The characteristic vesicles associated with the presence of bacteriochlorophyll were found in wild type cells grown with low aeration. These were also found in mutant TA-R which forms bacteriochlorophyli under high aeration. None of the mutants with blocks in bacte...

BACKGROUND Bacillus anthracis produces two catecholate siderophores, petrobactin and bacillibactin, under iron-limited conditions. Here, we investigate how variable iron and oxygen concentrations influence the biosynthetic output of both siderophores in B. anthracis. In addition, we describe the differential levels of transcription of select genes within the B. anthracis siderophore biosyntheti...

In this research, constructed wetlands were applied to remove the nitrogen of lightly polluted wastewater from a wastewater treatment plant in Tangshan. The results showed that a favorable removal effect of nitrogen could be obtained through constructed wetland. Moreover, the aeration device added to the bottom could increase the removal rates of ammonia nitrogen in lightly polluted wastewater,...

A laboratory-scale experiment presents data that reveal the temporal characteristics of solids, biochemical oxygen demand (BOD5) and volatile fatty acids (VFAs) in the aerated liquid swine manure for minimizing odor generation potential during 190-day storage. The performance of 15-day aeration of liquid manure with initial total solids (TS) content from 0.5% to 4.0% was examined at low-intensi...

This study investigated the influence of dissolved oxygen concentration and aeration time on nitrification and nitrite accumulation in an attempt to optimize the recently developed biological-partial-nitritation process for the treatment of strong nitrogen wastewaters. Investigation of dissolved oxygen concentration on ammonium and nitrite oxidation was carried out in a batch reactor. The disso...

INTRODUCTION There is an increasing interest in biphasic positive airway pressure with spontaneous breathing (BIPAP+SBmean), which is a combination of time-cycled controlled breaths at two levels of continuous positive airway pressure (BIPAP+SBcontrolled) and non-assisted spontaneous breathing (BIPAP+SBspont), in the early phase of acute lung injury (ALI). However, pressure support ventilation ...

Outdoor tanks containing the floating aquatic macrophyte water hyacinth [Eichhornia crassipes (Mart) Solms] were provided with diffuse aeration to evaluate its effect on wastewater treatment efficiency and plant growth. Light aeration (0.003 and 0.021 L nr min ') had no effect on the treatment of primary domestic effluent in the batch-fed water hyacinth tanks. Heavy aeration (1.03 and 3.53 L nr...

Enterotoxin B, nuclease, and total exoprotein production by Staphylococcus aureus strain S-6 was studied in a 0.5-liter fermentor system. While these extracellular products were elaborated over a wide range of aeration rates, maximal production occurred within the very narrow range of 125 to 150 cm(3) of air per min. The levels attained at the optimal aeration rate were not increased by maintai...

Campylobacter is one of the most commonly reported bacterial causes of human foodborne infections in the United States. Recent evidence has demonstrated that Campylobacter is present in poultry semen and may contribute to the vertical transmission between the breeder hen and offspring. As Campylobacter is considered sensitive to oxygen and cold temperature, the objective of this study was to de...

A direct relationship has been shown between the maximum cell concentration and aeration efficiency with aerobic microorganisms (Maxon and Johnson, 1953; Smith and Johnson, 1954). Since the antibiotic titer generally varies directly with the weight of mycelium in streptomycete fermentations, it is imperative to define the dependence of antibiotic and mycelial syntheses on the aeration efficienc...