The complete 1.66-megabase pair genome sequence of an autotrophic archaeon, Methanococcus jannaschii, and its 58- and 16-kilobase pair extrachromosomal elements have been determined by whole-genome random sequencing. A total of 1738 predicted protein-coding genes were identified; however, only a minority of these (38 percent) could be assigned a putative cellular role with high confidence. Although the majority of genes related to energy production, cell division, and metabolism in M. jannaschii are most similar to those found in Bacteria, most of the genes involved in transcription, translation, and replication in M. jannaschii are more similar to those found in Eukaryotes.
The naturally transformable, Gram-negative bacterium Haemophilus influenzae Rd preferentially takes up DNA of its own species by recognizing a 9-base pair sequence, 5'-AAGTGCGGT, carried in multiple copies in its chromosome. With the availability of the complete genome sequence, 1465 copies of the 9-base pair uptake site have been identified. Alignment of these sites unexpectedly reveals an extended consensus region of 29 base pairs containing the core 9-base pair region and two downstream 6-base pair A/T-rich regions, each spaced about one helix turn apart. Seventeen percent of the sites are in inverted repeat pairs, many of which are located downstream to gene termini and are capable of forming stem-loop structures in messenger RNA that might function as signals for transcription termination.
Human infection by leptospires has highly variable clinical manifestations, which range from subclinical infection to fulminant disease. We conducted a population-based, cross-sectional seroepidemiologic study in Peru to determine potential relationships of environmental context to human exposure to Leptospira and disease associated with seroconversion. Three areas were studied: a flooded, urban slum in the Peruvian Amazon city of Iquitos; rural, peri-Iquitos villages; and a desert shantytown near Lima. Seroprevalence in Belen was 28% (182/650); in rural areas, 17% (52/316); and in a desert shantytown, 0.7% (1/150). Leptospira-infected peridomestic rats were found in all locales. In Belen, 20 (12.4%) of 161 patients seroconverted between dry and wet seasons (an incidence rate of 288/1,000). Seroconversion was associated with history of febrile illness; severe leptospirosis was not seen. Human exposure to Leptospira in the Iquitos region is high, likely related both to the ubiquity of leptospires in the environment and human behavior conducive to transmission from infected zoonotic sources.
Twelve avian diseases are listed by the World Organisation for Animal Health (OIE), although more than 100 infectious diseases have been described in commercial poultry. This article summarises a recent assessment of the biosecurity risks posed by non-listed avian diseases associated with imports of chilled or frozen chicken meat and meat products into New Zealand. Following the guidelines described in Chapter 2.1 of the OIE Terrestrial Animal Health Code, avian adenovirus splenomegaly virus, avian paramyxovirus-2 (APMV-2), Bordetella avium, Mycoplasma spp., Ureaplasma spp., Ornithobacterium rhinotracheale, Riemerella anatipestifer, and Salmonella arizonae have been identified as hazards. However, of all the non-listed avian diseases discussed here, only APMV-2 and S. arizonae are assessed as being risks associated with the commercial import of chicken meat into New Zealand. Specific control measures may have to be implemented to mitigate such risks. This conclusion is likely to reflect both the high-health status of New Zealand poultry and the threat posed by these infectious agents to New Zealand's unique population of native psittacine species.
This paper describes an attempt to clone the Bacillus licheniformis lep gene, encoding signal peptidase, using the Salmonella typhimurium lep gene as a hybridization probe. Although a hybridizing fragment was obtained, DNA sequence analysis indicated that it did not contain the lep gene. Instead, the protein encoded by the cloned fragment showed similarity with a variety of L-asparaginases.
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