Cells of "Paenibacillus fukuinensis" D2 produced chitosanase into surrounding medium, in the presence of colloidal chitosan or glucosamine. The gene of this enzyme was cloned, sequenced, and subjected to site-directed mutation and deletion analyses. The nucleotide sequence indicated that the chitosanase was composed of 797 amino acids and its molecular weight was 85,610. Unlike conventional family 46 chitosanases, the enzyme has family 8 glycosyl hydrolase catalytic domain, at the amino-terminal side, and discoidin domain at the carboxyl-terminal region. Expression of the cloned gene in Escherichia coli revealed ␤-1,4-glucanase function, besides chitosanase activity. Analyses by zymography and immunoblotting suggested that the active enzyme was, after removal of signal peptide, produced from inactive 81-kDa form by proteolysis at the carboxyl-terminal region. Replacements of Glu 115 and Asp 176 , highly conserved residues in the family 8 glycosylase region, with Gln and Asn caused simultaneous loss of chitosanase and glucanase activities, suggesting that these residues formed part of the catalytic site. Truncation experiments demonstrated indispensability of an amino-terminal region spanning 425 residues adjacent to the signal peptide.

We tried to detect C. burnetii in market chicken eggs and mayonnaise by nested PCR assay. The PCR target was the com 1 gene of C. burnetii. The positive rate for egg and mayonnaise samples was 4.2% and 17.6%, respectively. Direct sequence of some of the positive egg samples shows mutations whereas no mutation was found in the positive mayonnaise samples. The number of molecules of the Q fever agent is estimated at 10(4) to 10(6) per egg, according to our quantitative PCR test.

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Oxidation of CO by 0, has been carried out over Rh/SiO, and Rh-Sn/SiO, catalysts. The temperature at which the activity for CO oxidation appeared was lowered in the presence of Sn. The reaction kinetics were not affected by the addition of Sn, the adsorption capacity for H, and CO decreased, whereas the capacity for 0, increased. Sn enhanced dissociative adsorption of molecular oxygen. Successive adsorption of CO and 0, indicated that the preadsorption of CO or 0, did not decrease the adsorption capacity of Rh-Sn/SiO, for 0, and CO, respectively. On the other hand, strong inhibition of the adsorption capacity was observed on Rh/SiO, after preadsorption. Temperature-programmed desorption of adsorbed CO and co-adsorbed CCO, showed that the chemisorption of CO on Rh was weakened by the addition of Sn and that a larger amount of CO, (product of CO oxidation reaction) was desorbed from Rh-Sn/SiO, than from Rh/SiO, . The surface reaction between adsorbed CO and 0 was enhanced by the addition of Sn. The role of Sn in Rh-Sn/SiO, for CO oxidation is considered as:(1) to enhance the activation of oxygen molecules, (2) to decrease the self-poisoning by CO and/or O, , (3) to enhance the surface reaction between adsorbed oxygen and weakly adsorbed CO.