Identification of linear plasmid pAM1 in the flavonoid degrading strain Actinoplanes missouriensis(T) (DSM 43046).

By pulsed-field gel electrophoresis, a linear DNA element of about 100 kb was identified in Actinoplanes missouriensis(T) DSM 43046, which grows on the flavonoids hesperidin, rutin and quercetin, and which contains a CO forming quercetinase. Among six Actinoplanes species and strains tested, including A. globisporus(T) DSM 43857, A. philippinensis(T) DSM 43019, A. brasiliensis(T) DSM 43805, A. auranticolor(T) DSM 43031, and A. utahensis(T) DSM 43147, only the A. missouriensis strain exhibited such a genetic element. The linear plasmid, named pAM1, has proteins covalently attached to its 5'-ends like other linear replicons of actinomycetes. Attempts to cure pAM1 failed, however a mutant with reduced plasmid content was obtained, which showed reduced ability to degrade the flavonoid rutinosides rutin and hesperidin. Plasmid pAM1 is the first extrachromosomal genetic element identified in an Actinoplanes species and may be useful to develop genetic tools for biotechnologically important Actinoplanes strains.

Occurrence and significance of precipitating antibodies against thermophilic actinomycetes in the sera of dairy herd workers, Nangali, Delhi.

The study was prompted by the lack of information on the role of thermophilic actinomycetes in hypersensitivity pneumonitis in India. It reports the occurrence of precipitating antibodies against clinically important thermophilic actinomycetes in the sera of a population sample of dairy herd workers, Nangali, Delhi. Of 112 workers investigated, 28 (25%) showed precipitins against Faenia rectivirgula, 4 (3.2%) against Saccharomonospora viridis, 2 against Thermoactinomyces thalpophilus and one each against T. vulgaris and T. sacchari. The results of enzyme-linked immunosorbent assay (ELISA) indicated that IgG antibody activity against F. rectivirgula was significantly higher in the symptomatic group than in the asymptomatic group (p less than 0.05) of workers and the controls (p less than 0.01). Significant difference in F. rectivirgula IgG activity was also obtained between the precipitin-positive symptomatic group and the precipitin-positive asymptomatic group (p less than 0.05). In strong contrast, the IgG antibody activity against T. thalpophilus was found to be uniformly low. A limited aeromicrobiological sampling of the dairy farm revealed S. viridis (55.8%) to be the commonest species followed by T. vulgaris (19.2%), T. thalpophilus (18.5%), F. rectivirgula (5%) and T. sacchari (1.5%). On the basis of suggestive clinical and laboratory findings, farmer's lung disease was suspected in four dairy herd workers. A comprehensive clinical evaluation including pulmonary function studies on the dairy herd workers and their long-term follow-up is indicated to determine the extent of respiratory morbidity caused by F. rectivirgula, S. viridis, T. thalpophilus, T. sacchari and T. vulgaris in India.

A partially purified antigen from Faenia rectivirgula in the diagnosis of farmer's lung disease.

An antigen fraction from Faenia rectivirgula (Micropolyspora faeni) having diagnostic significance for farmer's lung disease was isolated by Sephadex G-200 and G-100 fractionations. Antibody raised against this antigen fraction was used to make an immunoaffinity column to purify crude culture filtrate antigens of F. rectivirgula. The antigen has a molecular weight of 66,000 and an isoelectric point between pH 6.0 and 6.5. The yield of this antigen fraction was 1.02% of the total protein of the crude antigen. Although the crude antigen showed activity for several enzymes, the purified antigen showed enhanced activity for acid phosphatase and beta-glucosidase. Using this antigen fraction, an ELISA was developed for detecting circulating specific IgG antibody in farmer's lung patients. The antigen can be standardized by its immunochemical characteristics and may be used to detect circulating antibodies in the sera of patients with dependability and reproducibility.

Farmer's lung: immunological response to a group of extracellular enzymes of Micropolyspora faeni. An experimental and field study.

Potent immunogenicity of certain extracellular 'chymotrypsin-like' enzymes of Micropolyspora faeni are demonstrated. One of them, Enzyme 1 seems particularly active in stimulating the formation of percipitins after intratracheal exposure in rabbits. Man or cattle exposed naturally to mouldy hay, either with or without clinical farmer's lung symptoms show a rather constant immunological reaction against Enzyme 1 and partly also against others of the same group. The detection of specific percipitins against these enzymes is not likely to improve the diagnostic value of the standard farmer's lung serology. Possible implications of these proteolytic enzymes in the pathogenesis of farmer's lung are discussed.