Cellulase production from Pseudoalteromonas sp. NO3 isolated from the sea squirt Halocynthia rorentzi.
ABSTRACT Pseudoalteromonas sp. NO3 was isolated from the hemolymph of diseased sea squirts (Halocynthia rorentzi) with symptoms of soft tunic syndrome. The strain was found to produce an extracellular cellulase (CelY) that consisted of a 1,476 bp open reading frame encoding 491 amino acid residues with an approximate molecular mass of 52 kDa. Homologies of the deduced amino acid sequence of celY with the products of the celA, celX, celG and cel5Z genes were 92.6, 93.3, 92.6, and 59.1%, respectively. Additionally, CelY had 50-80% remnant catalytic activity at temperatures of 10-20 degrees C. Highest carboxymethyl cellulose (CMC) hydrolysis was observed at pH 8.0 and 40 degrees C. CMC activity was determined by zymogram active staining and different degraded product profiles for CelY were obtained when cellotetraose, cellopentaose, and CMC were used as substrates. This study identified a transglycosylation activity in CelY that allows the enzyme to digest G4 to G2 and G3 without the production of G1.
SourceAvailable from: Sylvatrie-Danne Dinzouna-Boutamba[Show abstract] [Hide abstract]
ABSTRACT: Ascidian soft tunic syndrome (AsSTS) caused by Azumiobodo hoyamushi (A. hoyamushi) is a serious aquaculture problem that results in mass mortality of ascidians. Accordingly, the early and accurate detection of A. hoyamushi would contribute substantially to disease management and prevention of transmission. Recently, the loop-mediated isothermal amplification (LAMP) method was adopted for clinical diagnosis of a range of infectious diseases. Here, the authors describe a rapid and efficient LAMP-based method targeting the 18S rDNA gene for detection of A. hoyamushi using ascidian DNA for the diagnosis of AsSTS. A. hoyamushi LAMP assay amplified the DNA of 0.01 parasites per reaction and detected A. hoyamushi in 10 ng of ascidian DNA. To validate A. hoyamushi 18S rDNA LAMP assays, AsSTS-suspected and non-diseased ascidians were examined by microscopy, PCR, and by using the LAMP assay. When PCR was used as a gold standard, the LAMP assay showed good agreement in terms of sensitivity, positive predictive value (PPV), and negative predictive value (NPV). In the present study, a LAMP assay based on directly heat-treated samples was found to be as efficient as DNA extraction using a commercial kit for detecting A. hoyamushi. Taken together, this study shows the devised A. hoyamushi LAMP assay could be used to diagnose AsSTS in a straightforward, sensitive, and specific manner, that it could be used for forecasting, surveillance, and quarantine of AsSTS.The Korean Journal of Parasitology 06/2014; 52(3):305-10. DOI:10.3347/kjp.2014.52.3.305 · 0.97 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: Cellulases which are active and stable under extreme conditions have attracted considerable attention because of their potential industrial applications. Marinimicrobium sp. LS-A18 showed high extracellular carboxymethylcellulase (CMCase) activity when grown on mineral salt medium containing carboxymethylcellulose as the sole carbon source. Maximum CMCase activity was obtained at 55°C and pH 7.0 in the absence of NaCl. Under the optimized fermentation conditions, the yield of CMCase was increased up to 2.5 U/ml, which was 3.1-fold higher than that before optimization. The enzyme retained 84 % of residual activity after incubation at 60°C for 1 h and more than 88 % of residual activity after incubation for 72 h in the presence of different pH (5-11) and NaCl concentrations (0-25 %, w/v), indicating it was halotolerant, thermostable and alkali-stable. These characteristics made the CMCase from Marinimicrobium sp. LS-A18 as a potentially novel biocatalyst in biotechnological and industrial applications.Applied biochemistry and biotechnology 07/2012; 168(3):550-67. DOI:10.1007/s12010-012-9796-3 · 1.69 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: The edible ascidian, sea squirt Halocynthia roretzi (Drasche) is marine invertebrate that is a valuable source of foods and bioactive compounds. A severe disease of the sea squirt characterized by degeneration of tunic fibers formed of bundled cellulose microfibrils has occurred. We hypothesized that bacteria lyse the cellulose fibril structure, cellulase activity may be a causative agent of the disease. Among the bacteria isolated from diseased sea squirt, Pseudoalteromonas sp. NO3 had cellulase activity based on a Congo red overlay assay and starch-reducing activity. Sea squirts exhibited 40–100% cumulative mortality after injection with Pseudoalteromonas sp. NO3 using doses of 2×106−2×108 colony forming unit (CFU)/individual. Dead sea squirts possess thinner and ruptured tunics, which were similar to natural outbreaks. These results suggest that Pseudoalteromonas sp. NO3 possessing cellulase activity is one of the causes of tunic softness syndrome in sea squirt.Food science and biotechnology 10/2012; 21(5). DOI:10.1007/s10068-012-0185-z · 0.66 Impact Factor