User:KosinskiJ

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A Microbial Biorealm page on the genus KosinskiJ

Classification

Higher order taxa

Bacteria; Spirochaetes; Spirochaetales; Leptospiraceae; Leptospira; Leptospira interrogans [1].

Species

NCBI: Taxonomy [1]

Leptospira interrogans

Description and significance

The Leptospira genus comprises a heterogeneous group of pathogenic and saprophytic species belonging to the phylum Spirochaetes [2]. Leptospires are thin, helically coiled, motile, Gram negative, obligate aerobic bacteria, classified into hundreds of pathogenic serovars [3]. They live optimally at temperatures between 28-30°C [4].

Genome structure

L. interrogans genome is circular and contains two chromosomes, a large and small, both containing 4,277,185 and 350,181 base pairs respectively, roughly 4,768 genes [5].Their genomes consist of 35% G-C content. The large chromosome contains Ribosomal RNA genes: two 23S, two 16S and one 5S genes [6]. They contain 37 genes encoding transfer RNAs. The low number of tRNA and rRNA genes may be attributed to the fastidious growth of the L. interrogans. [7].

Cell structure and metabolism

Given that L. interrogans is a Gram negative microorganism, the outer membrane consists of lipopolysaccharide proteins (LPS) [8]. Spirochetal outer membrane proteins, mostly porins, are predicted to span the lipid bilayer in multiple amphipathic, membrane-spanning beta sheets arranged in a barrel [9]. The outer face of the beta-sheets is hydrophobic and interacts with the lipid bilayer, while the inner face is hydrophilic and interacts with the aqueous pore of the protein [10].

L. interrogans are found to be obligate aerobes and undergo oxidative respiration for growth and survival [11]. They are physiologically chemoheterotrophic [12].

Ecology

The habitat in which this organism resides is typically in tropical and subtropical regions after heavy rainfall and dispersal of leptospires in contaminated water [13].

Pathology

This organism is the causative agent of leptospirosis, a tropical zoonosis transmitted by direct contact with the urine of infected animals via contaminated soil or fresh water [14]. These microorganisms have adapted for specific mammalian reservoir hosts, allowing them to harbor the hosts renal tubules and shed the Leptospira in their urine [15]. The range of carriers includes mammals, birds amphibians, reptiles and humans, who are rarely chronic carriers but can be accidental host [16]. For humans, fever, chills, headache, and severe myalgias characterize the early phase of the disease. In more severe cases, jaundice, renal, failure, and/or pulmonary hemorrhaging [17]. Progression to multi-organ system complications occurs in 5 to 15% of cases, with mortality rates of 5 to 40% [18]. Leptospirosis has recently been recognized as a ‘re-emerging infectious disease’ among humans and animals and has the potential to become even more prevalent with anticipated global warming [19].

Current Research and or Application to Biotechnology

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References

[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.

Edited by student of Dr. Lynn M Bedard, DePauw University http://www.depauw.edu