On the basis of DNADNA hybridisation there is 26 42 homology with T maritimum

On the basis of dnadna hybridisation there is 26 42

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On the basis of DNA:DNA hybridisation, there is 26-42% homology with T. maritimum. Certainly, the strains are distinct from T. maritimum, but it would be relevant to enquire about possible relationships with other cytophagas-flexibac- teria. Sporocytophaga spp. Negligible information is available about these Gram-negative, microcyst-forming organisms (see Pacha and Ordal, 1970). Francisellaceae representative Francisella sp. Francisella sp. Cultures initially developed small, opaque colonies on cysteine heart agar at 22°C, but not at 37°C. These colonies comprised non-motile, small (variable sizes). Gram-negative cysteine requiring strictly aerobic, catalase-negative (or weakly positive), oxidase-negative, non-haemolytic, facultatively intracellular cocco- bacilli that were examined by 16S rRNA sequencing for which the nearest match was Francisella philomiragia (99% identity) and several apparent Francisella from tilapia in Taiwan and three-lined grunt in Japan (Olsen et ciL, 2006). It was considered that the isolate from Atlantic cod was more fastidious that Francisella philonairagia (Olsen et al, 2006). Separately, intracellular bacteria were found in the kidney and spleen of three-line grunt from which DNA was extracted and small-subunit rRNA amplified by PCR, and sequenced. The outcome was 97.3-98.5% homology to Francisella, with Francisella philomiragia as the closest neighbour (Kamaishi et ai, 2005). Originally, Francisella philomiragia was classified in Yersinia as Y. philomiragia, which comprised bacteria first recovered from dying muskrat in Utah (Jensen et ai, 1969). The link to Yersinia resulted from the micro-morphology of the cells and supposed DNA related- ness to Y. pestis (Ritter and Gerloff, 1966). However, subsequent evaluation led to a transfer to Francisella (HolHs et ai, 1989).
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Characteristics of the pathogens: Gram-negative bacteria 123 Halomonadaceae representative Halomonas (=Deleya) cupida Homogenates of black sea bream revealed the presence of Halomonas (= Deleya) cupida (=Alcaligenes cupidus), V. alginolyticus and V. nereis (Kusuda et aL, 1986). H. cupida Cultures comprise motile, Gram-negative, salt-requiring rods, which grow at 10-25°C, but not at 4°C and 30°C, and are unreactive in the oxidative-fermenta- tive test. Arginine dihydrolase, catalase, and lysine and ornithine decarboxylase are produced, but not H2S, indole or oxidase. Nitrates are reduced, but the methyl red test and Voges Proskauer reaction are negative. Haemolysis is recorded to eel erythrocytes, but not those of sheep or yellowtail. Sensitivity is recorded to the vibriostatic agent, 0/129. Acid is produced from adonitol, galactose, lactose, maltose, mannitol, L-rhamnose, D-sorbitol, salicin, sucrose (weak) and trehalose, but not from fructose or inulin. From these characteristics, a close relationship to Alcaligenes cupidus was noted (see Kersters and De Ley, 1984). The only discrepancy concerned acid production from fructose. However, this taxon was re-classified as Deleya cupida (Baumann et aL, 1983), and by inference to Halomonas cupida on the basis of 16S rRNA sequenc- ing (Dobson and Franzmann, 1996).
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  • Bacteria, representative, gram-negative bacteria

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