| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Sevilla, 41012 Sevilla, Spain
Correspondence
A. Ventosa
ventosa{at}us.es
 |
ABSTRACT |
|---|
 TOP ABSTRACT MAIN TEXTREFERENCES |
|---|
|
MAIN TEXT |
|---|
|
TOPABSTRACTMAIN TEXTREFERENCES |
|---|
Moderately halophilic bacteria have adapted to live in a wide range of salt concentrations (3–15 % NaCl) and constitute an interesting group of micro-organisms that could be used as a source of such salt-adapted enzymes (Ventosa et al., 1998
). A screening programme to detect hydrolytic activities, such as protease, amylase, cellulase, pullulanase and lipase, has recently been performed in different hypersaline environments of southern Spain (Sánchez-Porro et al., 2003). This study revealed a wide diversity of moderately halophilic bacteria with the potential to hydrolyse a range of structurally non-related polymers. Among the isolates, 207 moderately halophilic bacteria that display lipolytic activity have been detected. Applications of lipolytic enzymes, which comprise mainly esterases and lipases, are widely found in the food, detergents, pharmaceutical and chemical industries (Jaeger et al., 1999; Pandey et al., 1999). A large number of microbial lipolytic enzymes has been identified and characterized to date; however, no lipolytic enzymes have so far been characterized from moderate halophiles. Taxonomic/phylogenetic studies performed on these halophilic, lipolytic enzyme producers accommodate them within different genera, such as Salinivibrio, Halomonas, Chromohalobacter, Salibacillus, Marinococcus and Marinobacter. In this study, the most promising isolate among the lipolytic producers, strain SM19T, was assigned to the genus Marinobacter. This genus was proposed by Gauthier et al. (1992), belongs to the 
-subclass of the class Proteobacteria and, at the time of writing, includes two species with validly published names: Marinobacter hydrocarbonoclasticus (Gauthier et al., 1992) and Marinobacter aquaeolei (Nguyen et al., 1999). Species of this genus are able to degrade hydrocarbons and some crude oil components.
In this work, we present a taxonomic/phylogenetic study of strain SM19T, a moderately halophilic bacterium that shows lipolytic activity with potential industrial applications, in order to establish its exact taxonomic position. We show that it constitutes a novel species of the genus Marinobacter, for which we propose the name Marinobacter lipolyticus sp. nov.
Strain SM19T was isolated from saline soil in Cádiz, Spain. The following reference strains were used for comparative purposes: M. hydrocarbonoclasticus DSM 8798T, M. hydrocarbonoclasticus DSM 50418 and Marinobacter aquaeolei DSM 11845T. M. hydrocarbonoclasticus DSM 50418 was the type strain of the former species Pseudomonas nautica (Baumann et al., 1972), which was transferred to the genus Marinobacter following a polyphasic taxonomic approach (Spröer et al., 1998) and, consequently, it has been included in this study. These strains were cultured on a saline medium (SW-7·5) with a total salt concentration of 7·5 % (w/v), supplemented with 0·5 % (w/v) yeast extract (Ventosa et al., 1982). All cultures were cultivated at 37 °C in an orbital shaker (New Brunswick Scientific) at 200 r.p.m. When necessary, solid media were prepared by adding 20 g Bacto-agar l-1 (Difco).
Standard phenotypic tests were performed to characterize this new isolate, including Gram reaction, cell morphology, motility, growth under anaerobic conditions, catalase and oxidase production, hydrolysis of gelatin, starch and Tween 80, as well as other tests that are included in the species description. Procedures for all tests have been described previously (Ventosa et al., 1982; Quesada et al., 1984; Garcia et al., 1987). Unless otherwise indicated, tests were performed in media that contained 7·5 % (w/v) salt, at pH 7·5 and incubated at 37 °C in sealed containers.
Strain SM19T is a Gram-negative, motile rod that grows optimally in media that contain approximately 7·5 % (w/v) salt and does not grow on nutrient agar without NaCl. This isolate can be considered as a moderately halophilic bacterium according to Kushner & Kamekura (1988). M. hydrocarbonoclasticus is an extremely halotolerant species, whereas M. aquaeolei is a moderately halophilic bacterium with optimal growth at 5 % NaCl. Strain SM19T grows at 15–40 °C and pH 5–10; optimal growth occurs at 37 °C and pH 7·5. The new isolate is strictly aerobic and catalase- and oxidase-positive.
Ability to utilize 95 different compounds was tested by using the Biolog GN automatic identification system. Strains were grown on isolate medium at 37 °C for 24 h and suspended in pre-warmed sterile saline medium (3 % NaCl) within the density range specified by the manufacturer (determined with a Biolog model 21101 photometer). Immediately after suspending the cells in saline solution, suspensions were transferred into sterile multichannel pipetter reservoirs and the Biolog GN MicroPlates were inoculated with 125 µl cell suspension per well by means of an eight-channel repeating pipetter. Inoculated Biolog GN plates were incubated at 37 °C for 24 h and the results were read with a MicroPlate reader, using MicroLog 3.59 computer software to perform automated reading and identification. The results obtained are included below in the description of the species.
In this work, the almost-complete 16S rDNA sequence (approx. 1443 nt) of strain SM19T was obtained. For this purpose, DNA was extracted and precipitated by following the CTAB (cetyltrimethylammonium bromide) protocol for bacterial genomic DNA preparation (Wilson, 1987) and PCR amplification of the 16S rRNA gene was carried out by using methods that have been described previously in detail (Mellado et al., 1995). 16S rDNA sequence analyses were performed with the ARB software package (Ludwig & Strunk, 1996) as reported by Arahal et al. (2002). Based on this analysis, the phylogenetic position of strain SM19T was determined to be within the genus Marinobacter (Fig. 1). With respect to the sequences of the type species of the genus, M. hydrocarbonoclasticus, similarities were between 96·4 % (with GenBank sequence no. X67022) and 96·7 % (with AB021372, Y16735 and AB019148). X67022 corresponds to strain ATCC 49840T, the type strain of the species, whereas AB021372 and AB019148 are equivalent sequences of M. hydrocarbonoclasticus ATCC 27132 (DSM 50418), which was the type strain of Pseudomonas nautica (Spröer et al., 1998). Although information about the strain used to obtain sequence Y16735 is not available, it is almost coincident with AB021372.
|
) is an ecological article that is related to the abundance of pelagic bacteria in the North Sea and does not follow polyphasic taxonomic criteria. In our opinion, it would be more appropriate to consider strain KT02sd19 as Marinobacter sp.
Highest similarity values to the sequence of strain SM19T (98·0–98·8 %) corresponded to partially determined sequences, which are not significant for taxonomic purposes. ‘Marinobacter marinus’ has low sequence similarity to strain SM19T (94·8 %) and ‘Marinobacter arcticus’ shows 98·0 % sequence similarity to strain SM19T. However, these names have not yet been validly published. Moreover, the article in which the latter organism is studied (Button & Robertson, 2001) does not report any taxonomic description of this species. In conclusion, the results of the phylogenetic analyses clearly indicate that strain SM19T belongs to the genus Marinobacter but is sufficiently distant (with similarity values of <97 %) to other members of the genus, giving support to its proposal as a novel species.
Cellular fatty acids of strain SM19T and the type strains of M. aquaeolei and M. hydrocarbonoclasticus were analysed with the MIDI Microbial Identification system. Cells were cultured in SW-7·5 medium at 37 °C for 24 h. Results of the cellular fatty acid analysis are shown in Table 1. The predominant fatty acids of strain SM19T were C16 : 0, C18 : 1
9c, C12 : 0 3-OH and C16 : 19c. The fatty acid profile is very similar to those of other species of the genus Marinobacter (Spröer et al., 1998; Nguyen et al., 1999).
|
and its G+C content was determined according to Marmur & Doty (1962) by using the equation of Owen & Hill (1979). The DNA G+C content of strain SM19T was 57·0 mol%. This value is similar to those described for M. hydrocarbonoclasticus (57·5 mol%; Spröer et al., 1998) and M. aquaeolei (55·7 mol%; Nguyen et al., 1999).
DNA–DNA hybridization was studied by the competition procedure of Johnson (1994), described in detail elsewhere (Arahal et al., 2001). Hybridization experiments were carried out under optimal conditions at a temperature of 54·5 °C, which is within the limits of validity for the filter method (De Ley & Tijtgat, 1970). Hybridization (%) was calculated as described by Johnson (1994). Hybridization levels between strain SM19T and M. hydrocarbonoclasticus and M. aquaeolei are shown in Table 2. The low hybridization values (11–19 %) obtained in this study clearly demonstrate that isolate SM19T represents a novel species of the genus Marinobacter.
|
). Highest activity was observed with p-nitrophenyl caprilate (100 %). Activity was lower towards p-nitrophenyl esters with a longer chain, such as p-nitrophenyl laureate (42 %), p-nitrophenyl palmitate (17 %) and p-nitrophenyl stearate (8 %). In addition, the production of extracellular lipolytic activity during growth of strain SM19T was determined. Strain SM19T was able to grow in saline media that contained 2–15 % total salt, with optimum growth at 7·5 % salt. To determine the influence of salt on lipolytic activity, different saline media were used for bacterial growth. The highest level of activity in the supernant was reached after 8 h cultivation in medium SW-7·5 at 37 °C and pH 7·2. Activity was slightly lower in saline medium that contained 5 % NaCl; however, activity decreased severely when SW-10 was used. Overall, our results show that strain SM19T represents a novel species of the genus Marinobacter, for which the name Marinobacter lipolyticus sp. nov. is proposed.
Description of Marinobacter lipolyticus sp. nov.
Marinobacter lipolyticus (li.po.ly'ti.cus. Gr. n. lipos fat; N.L. adj. lyticus from Gr. adj. lytikos dissolving; N.L. adj. lipolyticus fat-dissolving).
Gram-negative, rod-shaped cells that are 0·3–0·5x2·5–3·5 µm in size and occur singly, in pairs or in short chains. Motile and non-spore-forming. Colonies on SW-7·5 medium are circular, convex, slightly elevated, 2–3 mm in diameter and cream-pigmented. Growth occurs in the presence of 1–15 % (w/v) total salt; optimal growth occurs in the presence of 7·5 % (w/v) total salt. No growth occurs in the absence of salt. Grows occurs at 15–40 °C (optimal temperature, 37 °C) and at pH 5·0–10·0 (optimal pH, 7·5). Strictly aerobic. Catalase and oxidase are produced. Acid is produced from D-glucose, maltose and D-mannitol. Acid is not produced from glycerol, D-lactose or D-melibiose. Tween 80 is hydrolysed, but DNA, gelatin and starch are not. Indole, methyl red, phosphatase, Voges–Proskauer, phenylalanine deaminase, arginine dihydrolase and lysine and ornithine decarboxylase tests are negative. Simmons' citrate test is positive. Nitrate and nitrite are not reduced. The following compounds are utilized as sole carbon and energy sources: dextrin, glycogen, Tween 40, Tween 80, N-acetyl-D-glucosamine, D-fructose, D-glucose, maltose, D-mannitol, D-trehalose, methyl pyruvate, D-gluconic acid, inosine and thymidine. The following compounds are not utilized as sole carbon and energy sources: 
-cyclodextrin, N-acetyl-D-galactosamine, adonitol, L-arabinose, D-arabitol, cellobiose, i-erythritol, L-fucose, D-galactose, m-inositol, -D-lactose, lactulose, D-mannose, D-melibiose, methyl 
-D-glucoside, D-psicose, D-raffinose, L-rhamnose, D-sorbitol, sucrose, turanose, xylitol, monomethyl succinate, acetic acid, cis-aconitic acid, citric acid, formic acid, D-galactonic acid, D-glucosaminic acid, D-glucuronic acid, -hydroxybutyric acid, -hydroxybutyric acid, -hydroxybutyric acid, p-hydroxyphenylacetic acid, itaconic acid, -ketobutyric acid, -ketoglutaric acid, -ketovaleric acid, DL-lactic acid, malonic acid, propionic acid, quinic acid, D-saccharic acid, sebacic acid, succinic acid, bromosuccinic acid, succinamic acid, glucuronamide, alaninamide, D-alanine, L-alanine, L-alanylglycine, L-asparagine, L-aspartic acid, L-glutamic acid, glycyl L-aspartic acid, glycyl L-glutamic acid, L-histidine, hydroxy L-proline, L-leucine, L-ornithine, L-phenylalanine, L-proline, L-pyroglutamic acid, D-serine, L-serine, L-threonine, DL-carnitine, -aminobutyric acid, urocanic acid, uridine, phenylethylamine, putrescine, 2-aminoethanol, 2,3-butanediol, glycerol, DL--glycerol phosphate, glucose 1-phosphate and glucose 6-phosphate. The G+C content of the DNA is 57·0 mol% (Tm method).
The type strain is SM19T (=DSM 15157T=NCIMB 13907T =CIP 107627T=CCM 7048T). Habitat: saline soil.
|
ACKNOWLEDGEMENTS |
|---|
|
REFERENCES |
|---|
|
TOPABSTRACTMAIN TEXTREFERENCES |
|---|
Arahal, D. R., Ludwig, W., Schleifer, K. H. & Ventosa, A. (2002). Phylogeny of the family Halomonadaceae based on 23S and 16S rDNA sequence analyses. Int J Syst Evol Microbiol 52, 241–249.[Abstract]
Baumann, L., Baumann, P., Mandel, M. & Allen, R. D. (1972). Taxonomy of aerobic marine eubacteria. J Bacteriol 110, 402–429.
Button, D. K. & Robertson, B. R. (2001). Determination of DNA content of aquatic bacteria by flow cytometry. Appl Environ Microbiol 67, 1636–1645.
De Ley, J. & Tijtgat, R. (1970). Evaluation of membrane filter methods for DNA-DNA hybridization. Antonie van Leeuwenhoek 36, 461–474.[CrossRef][Medline]
Eilers, H., Pernthaler, J., Glöckner, F. O. & Amann, R. (2000). Culturability and in situ abundance of pelagic bacteria from the North Sea. Appl Environ Microbiol 66, 3044–3051.
Garcia, M. T., Ventosa, A., Ruiz-Berraquero, F. & Kocur, M. (1987). Taxonomic study and amended description of Vibrio costicola. Int J Syst Bacteriol 37, 251–256.
Gauthier, M. J., Lafay, B., Christen, R., Fernandez, L., Acquaviva, M., Bonin, P. & Bertrand, J.-C. (1992). Marinobacter hydrocarbonoclasticus gen. nov., sp. nov., a new, extremely halotolerant, hydrocarbon-degrading marine bacterium. Int J Syst Bacteriol 42, 568–576.
Jaeger, K. E., Dijkstra, B. W. & Reetz, M. T. (1999). Bacterial biocatalysts: molecular biology, three-dimensional structures, and biotechnological applications of lipases. Annu Rev Microbiol 53, 315–351.[CrossRef][Medline]
Johnson, J. L. (1994). Similarity analysis of DNAs. In Methods for General and Molecular Bacteriology, pp. 655–681. Edited by P. Gerhardt, R. G. E. Murray, W. A. Wood & N. R. Krieg. Washington, DC: American Society for Microbiology.
Kushner, D. J. & Kamekura, M. (1988). Physiology of halophilic eubacteria. In Halophilic Bacteria, vol. I, pp. 109–140. Edited by F. Rodríguez-Valera. Boca Raton, FL: CRC Press.
Ludwig, W. & Strunk, O. (1996). ARB – a software environment for sequence data (http://www.arb-home.de/).
Marmur, J. (1961). A procedure for the isolation of deoxyribonucleic acid from microorganisms. J Mol Biol 3, 208–218.
Marmur, J. & Doty, P. (1962). Determination of the base composition of deoxyribonucleic acid from its thermal denaturation temperature. J Mol Biol 5, 109–118.[Medline]
Mellado, E., Moore, E. R. B., Nieto, J. J. & Ventosa, A. (1995). Phylogenetic inferences and taxonomic consequences of 16S ribosomal DNA sequence comparison of Chromohalobacter marismortui, Volcaniella eurihalina, and Deleya salina and reclassification of V. eurihalina as Halomonas eurihalina comb. nov. Int J Syst Bacteriol 45, 712–716.
Nguyen B. H., Denner, E. B. M., Dang, T. C. H., Wanner, G. & Stan-Lotter, H. (1999). Marinobacter aquaeolei sp. nov., a halophilic bacterium isolated from a Vietnamese oil-producing well. Int J Syst Bacteriol 49, 367–375.
Owen, R. J. & Hill, L. R. (1979). The estimation of base compositions, base pairing and genome size of bacterial deoxyribonucleic acids. In Identification Methods for Microbiologists, 2nd edn, pp. 217–296. Edited by F. A. Skinner & D. W. Lovelock. London: Academic Press.
Pandey, A., Benjamin, S., Soccol, C. R., Nigam, P., Krieger, N. & Soccol, V. T. (1999). The realm of microbial lipases in biotechnology. Biotechnol Appl Biochem 29, 119–131.
Quesada, E., Ventosa, A., Ruiz-Berraquero, F. & Ramos-Cormenzana, A. (1984). Deleya halophila, a new species of moderately halophilic bacteria. Int J Syst Bacteriol 34, 287–292.
Sánchez-Porro, C., Martín, S., Mellado, E. & Ventosa, A. (2003). Diversity of moderately halophilic bacteria producing extracellular hydrolytic enzymes. J Appl Microbiol 94, 295–300.[CrossRef][Medline]
Spröer, C., Lang, E., Hobeck, P., Burghardt, J., Stackebrandt, E. & Tindall, B. J. (1998). Transfer of Pseudomonas nautica to Marinobacter hydrocarbonoclasticus. Int J Syst Bacteriol 48, 1445–1448.
Ventosa, A., Quesada, E., Rodriguez-Valera, F., Ruiz-Berraquero, F. & Ramos-Cormenzana, A. (1982). Numerical taxonomy of moderately halophilic Gram-negative rods. J Gen Microbiol 128, 1959–1968.
Ventosa, A., Nieto, J. J. & Oren, A. (1998). Biology of moderately halophilic aerobic bacteria. Microbiol Mol Biol Rev 62, 504–544.
Wilson, K. (1987). Preparation of genomic DNA from bacteria. In Current Protocols in Molecular Biology, pp. 2.4.1–2.4.2. Edited by F. M. Ausubel, R. Brent, R. E. Kingston, D. D. Moore, J. G. Seidman, J. A. Smith & K. Struhl. New York: Wiley.
Winkler, U. K. & Stuckmann, M. (1979). Glycogen, hyaluronate, and some other polysaccharides greatly enhance the formation of exolipase by Serratia marcescens. J Bacteriol 138, 663–670.
This article has been cited by other articles:
|
|
 |
|
  M. J. Montes, N. Bozal, and E. Mercade Marinobacter guineae sp. nov., a novel moderately halophilic bacterium from an Antarctic environment Int J Syst Evol Microbiol, June 1, 2008; 58(6): 1346 - 1349. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
X.-W. Xu, Y.-H. Wu, C.-S. Wang, J.-Y. Yang, A. Oren, and M. Wu Marinobacter pelagius sp. nov., a moderately halophilic bacterium Int J Syst Evol Microbiol, March 1, 2008; 58(3): 637 - 640. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Guo, J. Gu, Y.-G. Ye, Y.-Q. Tang, K. Kida, and X.-L. Wu Marinobacter segnicrescens sp. nov., a moderate halophile isolated from benthic sediment of the South China Sea Int J Syst Evol Microbiol, September 1, 2007; 57(9): 1970 - 1974. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. A. Mikucki and J. C. Priscu Bacterial Diversity Associated with Blood Falls, a Subglacial Outflow from the Taylor Glacier, Antarctica Appl. Envir. Microbiol., June 15, 2007; 73(12): 4029 - 4039. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Antunes, L. Franca, F. A. Rainey, R. Huber, M. F. Nobre, K. J. Edwards, and M. S. da Costa Marinobacter salsuginis sp. nov., isolated from the brine-seawater interface of the Shaban Deep, Red Sea Int J Syst Evol Microbiol, May 1, 2007; 57(5): 1035 - 1040. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Gu, H. Cai, S.-L. Yu, R. Qu, B. Yin, Y.-F. Guo, J.-Y. Zhao, and X.-L. Wu Marinobacter gudaonensis sp. nov., isolated from an oil-polluted saline soil in a Chinese oilfield Int J Syst Evol Microbiol, February 1, 2007; 57(2): 250 - 254. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P.-P. Liebgott, L. Casalot, S. Paillard, J. Lorquin, and M. Labat Marinobacter vinifirmus sp. nov., a moderately halophilic bacterium isolated from a wine-barrel-decalcification wastewater. Int J Syst Evol Microbiol, November 1, 2006; 56(Pt 11): 2511 - 2516. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B.-Y. Kim, H.-Y. Weon, S.-H. Yoo, J.-S. Kim, S.-W. Kwon, E. Stackebrandt, and S.-J. Go Marinobacter koreensis sp. nov., isolated from sea sand in Korea. Int J Syst Evol Microbiol, November 1, 2006; 56(Pt 11): 2653 - 2656. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. H. Green, J. P. Bowman, E. A. Smith, T. Gutierrez, and C. J. S. Bolch Marinobacter algicola sp. nov., isolated from laboratory cultures of paralytic shellfish toxin-producing dinoflagellates. Int J Syst Evol Microbiol, March 1, 2006; 56(Pt 3): 523 - 527. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J.-M. Lim, C. O. Jeon, J.-C. Lee, S.-M. Song, K.-Y. Kim, and C.-J. Kim Marinimicrobium koreense gen. nov., sp. nov. and Marinimicrobium agarilyticum sp. nov., novel moderately halotolerant bacteria isolated from tidal flat sediment in Korea. Int J Syst Evol Microbiol, March 1, 2006; 56(Pt 3): 653 - 657. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Shivaji, P. Gupta, P. Chaturvedi, K. Suresh, and D. Delille Marinobacter maritimus sp. nov., a psychrotolerant strain isolated from sea water off the subantarctic Kerguelen islands Int J Syst Evol Microbiol, July 1, 2005; 55(4): 1453 - 1456. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. C. Marquez and A. Ventosa Marinobacter hydrocarbonoclasticus Gauthier et al. 1992 and Marinobacter aquaeolei Nguyen et al. 1999 are heterotypic synonyms Int J Syst Evol Microbiol, May 1, 2005; 55(3): 1349 - 1351. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. A. Romanenko, P. Schumann, M. Rohde, N. V. Zhukova, V. V. Mikhailov, and E. Stackebrandt Marinobacter bryozoorum sp. nov. and Marinobacter sediminum sp. nov., novel bacteria from the marine environment Int J Syst Evol Microbiol, January 1, 2005; 55(1): 143 - 148. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J.-H. Yoon, S.-H. Yeo, I.-G. Kim, and T.-K. Oh Marinobacter flavimaris sp. nov. and Marinobacter daepoensis sp. nov., slightly halophilic organisms isolated from sea water of the Yellow Sea in Korea Int J Syst Evol Microbiol, September 1, 2004; 54(5): 1799 - 1803. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J.-H. Yoon, T.-K. Oh, and Y.-H. Park Kangiella koreensis gen. nov., sp. nov. and Kangiella aquimarina sp. nov., isolated from a tidal flat of the Yellow Sea in Korea Int J Syst Evol Microbiol, September 1, 2004; 54(5): 1829 - 1835. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| INT J SYST EVOL MICROBIOL | MICROBIOLOGY | J GEN VIROL |
| J MED MICROBIOL | ALL SGM JOURNALS | |
