User:Mws711/sandbox

Legionella cherrii (abbreviated as L. cherrii) is an aerobic, flagellated, gram negative bacteria from the genus Legionella that lacks the ability to form spores. It was isolated from a heated water sample in Minnesota. L. cherrii is similar to another Legionella species called Legionella pneumophila and is believed to cause major respiratory problems.

Discovery
The bacteria was first discovered by R. L. Tyndall and C. B. Duncan in 1982 who were a part of D.J. Brenner's team that discovered ten new species of Legionella. The isolation process initiated after collecting water samples and transferring them into guinea pig tissues before plating them onto buffered charcoal yeast extract agar (BCYE). Afterwords, L. cherrii strains on the CYE were cultured around 36 degrees Celsius in an environment containing 2.5% carbon dioxide.

Etymology
The genus Legionella is named after the 1976 pneumonia (Legionella pneumophila) outbreak at the American Legion convention at the Bellevue-Stratford Hotel in Philadelphia. The genus was previously unknown, but it was established three years later. The species term cherrii is derived from the scientist William B. Cherry due to his contributions on the studies of Legionellae.

Characterization and Genomics
Legionella cherrii is rod shaped and considered an oxidase-negative bacteria since it lacks cytochrome c oxidase and does not use oxygen in its electron transport chain. Brenner et. al performed an oxidase test under the instructions of Weaver and Feeley. L. cherrii also has the ability to auto-fluoresce a bluish-white color which was tested by placing the specimen under a Woods lamp-a mechanism that uses backlight to highlight bacteria-and measured under 366nm wavelengths. BCYE agar cultures were grown around 36 degrees Celsius. L. cherrii lacks the ability to reduce nitrate, does not contain a urease, or convert D-glucose to acid. This was determined by following Orrison et. al and Weaver and Feeley's methods respectfully. However, L. cherrii can ferment catalase and hydrolyze gelatin. When on a yeast extract agar plate, L. cherrii forms a dissolvable brown pigment containing tyrosine. One or a few flagella aid them in their motility. Legionella organisms’ dependence on L-cysteine as well as their unique fatty acids and isoprenoid ubiquinone, distinguishes them from other aerobic bacteria. Four strains of L. cherrii (ORB, ORZ, SC-65-C3, and ORW) as well as previously classified strains of Legionella were Gram-stained via the Hucker method. The Clark modification of the Leifson method was used also to stain flagellum. Like other Legionella species, L. cherrii does not form spores and is an aerobic, gram-negative bacterium. The genome size was sequenced using Illumina HiSeq 2000 and found to be 3.7 Mb. Scaffold assembly was conducted using whole genome shotgun sequencing and 13 scaffolds were found in the complete genome. The G/C content for this particular species of Legionella is 38.8 mol %. 3,111 protein coding genes, 4 rRNA genes, and 36 tRNA genes were also discovered in the genome.

Ecology
Various strains of L. cherrii were isolated in different areas in 1982. Strains ORW, ORB, and ORZ were discovered in Minnesota via a heated water sample. Another isolate, SC-65-C3, was found in a potable water stern on the island of St. Croix which is located in the Virgin Islands. Legionellae are mostly found in freshwater environments. However, various strains of Legionellae can congregate in water filtration systems, air conditioning units, humidifiers, and equipment used to combat respiratory infections.

Phylogeny
To determine previously classified Legionellae species relatedness to L. cherrii, Brenner et. al hybridized DNA reactions using an in vitro method with phosphate (32PO4). A similarity percent of 94% or higher was found between the four L. cherrii strains. Reassociation criteria differed between 60 to 75 degrees Celsius depending on the optimal or stringent growth of the bacteria. 0.0-0.5% divergence was found in related sequences. L. steigerwaltii was related to L. cherrii the most, and exhibited a 67% relatedness percent. Following L. steigerwalti, L. dumofii (57%), L anisa (56%), L. bozemanii (51%), and L. gormanii (47%) showed these levels of similarity. Although L. parisiensis is an auto-fluorescent species like L. cherrii, it only had a 24% relatedness percent to L. cherrii. Compared to other Legionella species, L. cherrii is 6-35% related.

Pathogenesis
Legionella cherrii as well as other Legionellae are considered to be intracellular bacteria that can cause major respiratory problems in humans. Infection occurs when a human host inhales the organism which may be carried in humidified air. It is difficult to distinguish patients with Legionnaire’s disease on the account that most are asymptomatic due to the effect that Legionnaire’s disease is similar to other types of pneumonia. Although L. pneumophila is the leading cause of Legionnaire’s disease, it is likely that other Legionellae (such as L. cherrii) are capable of causing this disease. The cultural growth period for Legionellae is typically 3-4 days. Lung biopsy or bronchoscopy are not necessary to obtain a clinical isolate from a human patient. Pre-plated acidification or using BCYE agar increases the level of selectivity and allows easier access to collecting a Legionella sample from an infected human’s sputum. Not much is known on how to treat Legionnaire’s disease, but one way could be to reduce the amount of biofilm production that Legionellae create.