A three-dimensional (3-D) diffusion-reaction model was used to assess the effects of nitrifiers growing in cell clusters on the apparent oxygen half-saturation coefficients in activated sludge flocs. The model allows conciliation of seemingly contradictory reports by several research groups. Although intrinsic half-saturation coefficients (i.e., not affected by diffusion) show a better affinity...

The first step of nitrification, the oxidation of ammonia to nitrite, can be performed by ammonia-oxidizing archaea (AOA) or ammonium-oxidizing bacteria (AOB). We investigated the presence of these two groups in three structurally different types of coastal microbial mats that develop along the tidal gradient on the North Sea beach of the Dutch barrier island Schiermonnikoog. The abundance and ...

Karen M. Carney,* Pamela A. Matson and Brendan J. M. Bohannan Smithsonian Environmental Research Center, P.O. Box 28, Edgewater, MD 21037, USA Department of Geological and Environmental Sciences, Stanford University, Stanford, CA 94305, USA Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA *Correspondence: E-mail: [email protected] Abstract Ammonia-oxidizing bact...

Both ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) play an important role in nitrification in terrestrial environments. Most often AOA outnumber AOB, but the relative contribution of AOA and AOB to nitrification rates remains unclear. The aim of this experiment was to test the hypotheses that high nitrogen availability would favor AOB and result in high gross nitrificatio...

Ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) are a diverse and functionally important group in the nitrogen cycle. Nevertheless, AOA and AOB communities driving this process remain uncharacterized in tropical freshwater sediment. Here, the effect of human settlement on the AOA and AOB diversity and abundance have been assessed by phylogenetic and quantitative PCR analyse...

BACKGROUND Anterior open bite is said to exist when there is an actual vertical gap between the upper and lower incisors with the teeth in centric occlusion. This could occur in the anterior or posterior region, and may be attributed to the supra eruption of the posterior teeth or the infra eruption of the anterior teeth and it is common in both adults and children. OBJECTIVE To evaluate the ...

Antioxidant of bamboo leaves (AOB) was certified to be a natural antioxidant by the Chinese Ministry of Health in 2003. However, the effects of AOB on animal reproductive and developmental functions remain unclear. The present study aimed to investigate the effects of different concentrations of AOB on mouse embryonic fibroblast (MEF) cells, and to examine the underlying molecular mechanism thr...