Enrichment and identification of large filamentous sulfur bacteria related to Beggiatoa species from brackishwater ecosystems of Tamil Nadu along the southeast coast of India.

Beggiatoa species are filamentous sulfide-oxidizing bacteria belonging to the family Beggiatoaceae that contains several largest bacteria known today. These large sulfur bacteria occur in diverse ecosystems and play an important role in the global sulfur, nitrogen and phosphorus cycle. In this study, sediment samples from brackishwater shrimp culture ponds and other brackishwater ecosystems from Tamil Nadu, southeast coast of India, were enriched for Beggiatoa species. Extracted hay medium supplemented with catalase was used and were incubated for two weeks at 28°C. Out of seven set-ups, four yielded positive growth of filamentous sulfide-oxidizing bacteria. The filaments were several millimeters long, ranged in width between 2 and 15 µm and exhibited typical gliding motility. The 16S rRNA gene of four single filaments representing the four positive enrichments was subjected to PCR-DGGE followed by sequencing. All four filaments were affiliated to the Beggiatoaceae, but showed less than 89% identity with the Beggiatoa type strain Beggiatoa alba and less than 93% identity with any other sequence of the family. One of the four filaments revealed a nearly full-length 16S rDNA sequence (1411bp) and it formed a monophyletic cluster with two of the partial DGGE-16S rRNA gene sequences (99-100% identity) within the Beggiatoa species cluster. These organisms could possibly represent a novel genus within the family Beggiatoaceae. The fourth partial sequence affiliated with less than 93% sequence identity to the genera Parabeggiatoa, Thioploca and Thiopilula, and was likewise strongly delineated from any sequence published in the family.

[Effect of captopril on pulmonary function].

During the past few years, dry cough has been described as a possible adverse effect of treatment with angiotensin converting enzyme (ACE) inhibitors. There have been several studies of the effect of long-term administration of ACE inhibitors on pulmonary function. We examined spirometrically the effect of a single oral dose of captopril (25 mg) on bronchial tonus in those who had not received the drug previously, in 4 patients who had previously had dry cough during ACE inhibitor therapy, in 20 patients with obstructive pulmonary disease and in 20 control subjects without pulmonary disease. 1 hour after ingestion of captopril there were no significant changes in the spirometric tests of any group. These findings supplement the results of similar tests done during longterm administration of ACE inhibitors, indicating that the pathogenesis of cough elicited by ACE inhibitor therapy does not seem to have an asthmatic basis.