Ammonia-oxidizing bacteria rather than ammonia-oxidizing archaea were widely distributed in animal manure composts from field-scale facilities.

The distribution of ammonia-oxidizing archaea (AOA) and bacteria (AOB) in cattle, swine, and chicken manure compost was analyzed. PCR-denaturing gradient gel electrophoresis (DGGE) showed that a Candidatus Nitrososphaera gargensis-like sequence dominated in cattle manure compost, while few AOA were detected in other composts. In the case of AOB, Nitrosomonas-like sequences were detected with higher diversity in cattle and swine manure composts. The relative abundance of ammonia oxidizers by real-time PCR revealed that more AOB was present in compost except in one swine manure compost. Our results indicated that AOB rather than AOA are widely distributed in animal manure compost.

Ammonia-oxidizing Archaea in laboratory-scale activated sludge systems for wastewater of low- or high-ammonium concentration.

Ammonia-oxidizing bacteria (AOB) is known as ammonia-oxidizer in wastewater treatment systems. However, ammonia-oxidizing Archaea (AOA) is found from various environments, including wastewater treatment systems. In this study, to investigate the relationships between AOA population and ammonia concentration, AOA was monitored in two laboratory-scale reactors treating artificial wastewater of different ammonium concentrations by denaturing gradient gel electrophoresis targeting ammonia monooxygenase genes. At day 60 of the operation, AOA populations dominant in each reactor differed, suggesting the importance of influent ammonia concentration in dominant AOA selection.

Growth of ammonia-oxidizing archaea and bacteria in cattle manure compost under various temperatures and ammonia concentrations.

A recent study showed that ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) coexist in the process of cattle manure composting. To investigate their physiological characteristics, liquid cultures seeded with fermenting cattle manure compost were incubated at various temperatures (37°C, 46°C, or 60°C) and ammonium concentrations (0.5, 1, 4, or 10 mM NH (4) (+) -N). The growth rates of the AOB and AOA were monitored using real-time polymerase chain reaction analysis targeting the bacterial and archaeal ammonia monooxygenase subunit A genes. AOB grew at 37°C and 4 or 10 mM NH (4) (+) -N, whereas AOA grew at 46°C and 10 mM NH (4) (+) -N. Incubation with allylthiourea indicated that the AOB and AOA grew by oxidizing ammonia. Denaturing gradient gel electrophoresis and subsequent sequencing analyses revealed that a bacterium related to Nitrosomonas halophila and an archaeon related to Candidatus Nitrososphaera gargensis were the predominant AOB and AOA, respectively, in the seed compost and in cultures after incubation. This is the first report to demonstrate that the predominant AOA in cattle manure compost can grow and can probably oxidize ammonia under moderately thermophilic conditions.

The first detection of Cryptosporidium deer-like genotype in cattle in Japan.

The general perception is that cattle are major reservoirs for Cryptosporidium parvum infections in humans and that C. parvum is a major cause of diarrhea and production loss in cattle. Adult cattle may play an important role as cryptic carrier of the infection. Cryptosporidium spp. in asymptomatic adult dairy cattle from some farms around Osaki area, Miyagi prefecture, Japan, was examined on a field visit during August, 2007, by polymerase chain reaction techniques for detection, genotyping, and subtyping. Cryptosporidium oocysts were detected in the feces of five out of 50 animals. Of the five Cryptosporidium-positive specimens available for molecular analysis, C. parvum was identified in three specimens, Cryptosporidium deer-like genotype in one, and Cryptosporidium andersoni in one specimen. Amplification of Cpgp60 from C. andersoni and Cryptosporidium deer-like genotype samples revealed that these samples have light concurrent C. parvum infection. Sequence analysis of the 60-kDa glycoprotein gene indicated that all C. parvum samples are IIa subtype. Detection of Cryptosporidium deer-like genotype is geographically unique in Japan. The genetic diversity of Cryptosporidium in dairy cattle in Japan may be much greater than that reported before.