Tenacibaculum skagerrakense sp. nov., a marine bacterium isolated from the pelagic zone in Skagerrak, Denmark.
Frette, L., Jørgensen, N. O. G., Irming, H. & Kroer, N. (2004). International Journal of Systematic and Evolutionary Microbiology, 54(2), 519-524.
A number of bacteria were isolated from sea water in Skagerrak, Denmark, at 30 m depth. Two of the isolates, strains D28 and D30T, belonged to the Flavobacteriaceae within the Cytophaga–Flavobacterium–Bacteroides group. Sequencing of 16S rRNA genes of the two strains indicated strongly that they belonged to the genus Tenacibaculum and that they showed greatest similarity to the species Tenacibaculum amylolyticum and Tenacibaculum mesophilum. DNA–DNA hybridization values, DNA base composition and phenotypic characteristics separated the Skagerrak strains from the other species within Tenacibaculum. Thus, it is concluded that the strains belong to a novel species within the genus Tenacibaculum, for which the name Tenacibaculum skagerrakense sp. nov. is proposed, with strain D30T (=ATCC BAA-458T=DSM 14836T) as the type strain.
Diversity and cold-active hydrolytic enzymes of culturable bacteria associated with Arctic sea ice, Spitzbergen.
Groudieva, T., Kambourova, M., Yusef, H., Royter, M., Grote, R., Trinks, H. & Antranikian, G. (2004). Extremophiles, 8(6), 475-488.
The diversity of culturable bacteria associated with sea ice from four permanently cold fjords of Spitzbergen, Arctic Ocean, was investigated. A total of 116 psychrophilic and psychrotolerant strains were isolated under aerobic conditions at 4°C. The isolates were grouped using amplified rDNA restriction analysis fingerprinting and identified by partial sequencing of 16S rRNA gene. The bacterial isolates fell in five phylogenetic groups: subclasses α and γof Proteobacteria, the Bacillus–Clostridium group, the order Actinomycetales, and the Cytophaga–Flexibacter–Bacteroides (CFB) phylum. Over 70% of the isolates were affiliated with the Proteobacteria γ subclass. Based on phylogenetic analysis (<98% sequence similarity), over 40% of Arctic isolates represent potentially novel species or genera. Most of the isolates were psychrotolerant and grew optimally between 20 and 25°C. Only a few strains were psychrophilic, with an optimal growth at 10–15°C. The majority of the bacterial strains were able to secrete a broad range of cold-active hydrolytic enzymes into the medium at a cultivation temperature of 4°C. The isolates that are able to degrade proteins (skim milk, casein), lipids (olive oil), and polysaccharides (starch, pectin) account for, respectively, 56, 31, and 21% of sea-ice and seawater strains. The temperature dependences for enzyme production during growth and enzymatic activity were determined for two selected enzymes, α-amylase and β-galactosidase. Interestingly, high levels of enzyme productions were measured at growth temperatures between 4 and 10°C, and almost no production was detected at higher temperatures (20–30°C). Catalytic activity was detected even below the freezing point of water (at −5°C), demonstrating the unique properties of these enzymes.
Bacillus plakortidis sp. nov. and Bacillus murimartini sp. nov., novel alkalitolerant members of rRNA group 6.
Borchert, M. S., Nielsen, P., Graeber, I., Kaesler, I., Szewzyk, U., Pape, T., Antranikian, G. & Schäfer, T. (2007). International Journal of Systematic and Evolutionary Microbiology, 57(12), 2888-2893.
The Gram-positive, alkali- and salt-tolerant marine bacterium strain P203T is described together with its closest phylogenetic neighbour, terrestrial isolate LMG 21005T. Strain P203T was isolated from material from the sponge Plakortis simplex that was obtained from the Sula-Ridge, Norwegian Sea. Strain LMG 21005T was an undescribed strain that was isolated from a church wall mural in Germany. Strains P203T and LMG 21005T were identified as novel alkalitolerant members of the Bacillus rRNA group 6 with a 16S rRNA gene sequence similarity of 99.5 %. The closest described neighbour, Bacillus gibsonii DSM 8722T, showed 99.0 % gene sequence similarity with P203T and 98.8 % similarity with strain LMG 21005T. Despite the high 16S rRNA gene sequence similarity, DNA–DNA cross-hybridization revealed only 25.8–34.1 % similarity amongst the three strains. The DNA G+C contents were 41.1 mol% for strain P203T and 39.6 mol% for strain LMG 21005T. Both strains grew well between pH 7 and pH 11. Strain P203T showed growth at moderate temperatures (from 4 to 30°C) and in the presence of up to 12 % (w/v) NaCl at pH 9.7, whereas strain LMG 21005T was not salt tolerant (up to 4 % NaCl) and no growth was observed at 4°C. The major fatty acids of strains P203T, LMG 21005T and the type strain of B. gibsonii were the saturated terminally methyl-branched compounds iso-C15 : 0 (19.8, 15.6 and 28.0 %, respectively) and anteiso-C15 : 0 (57.1, 48.6 and 45.2 %, respectively). Physiological and biochemical tests allowed genotypic and phenotypic differentiation of strains P203T and LMG 21005T from the six related Bacillus species with validly published names and supported the proposal of two novel species, Bacillus plakortidis [type strain P203T (=DSM 19153T=NCIMB 14288T)] and Bacillus murimartini [type strain LMG 21005T (=NCIMB 14102T)].
Reclassification of ‘Pseudomonas fluorescens subsp. cellulosa’ NCIMB 10462 (Ueda et al. 1952) as Cellvibrio japonicus sp. nov. and revival of Cellvibrio vulgaris sp. nov., nom. rev. and et al.
Humphry, D. R., Black, G. W. & Cummings, S. P. (2003). International Journal of Systematic and Evolutionary Microbiology, 53(2), 393-400.
Reclassification of ‘Pseudomonas fluorescens subsp. cellulosa’ NCIMB 10462 (Ueda et al. 1952) as Cellvibrio japonicus sp. nov. and revival of Cellvibrio vulgaris sp. nov., nom. rev. and Cellvibrio fulvus sp. nov., nom. rev.
Pseudomonas fluorescens subsp. cellulosa’ NCIMB 10462 has been demonstrated by a polyphasic taxonomic approach to be a member of the genus Cellvibrio. 16S rDNA sequence analysis suggests that this is the only genus that could accept this specimen. The sequence is 95·5 % similar to that of Cellvibrio mixtus subsp. mixtus ACM 2601T (the type strain of the type species of the genus), which is its closest relation. The genomic DNA G+C content was determined to be 53·3 mol%, which is similar to the values obtained for the validly described Cellvibrio species. DNA–DNA hybridization experiments have shown that strain NCIMB 10462T (=NCDO 2697T) represents a novel species; therefore, it is proposed that it be designated as the type strain of the novel species Cellvibrio japonicas sp. nov. This study also used 16S rDNA analysis, DNA–DNA hybridization experiments and phenotypic testing to revive the species Cellvibrio vulgaris sp. nov., nom. rev. and Cellvibrio fulvus sp. nov., nom. rev. C. vulgaris NCIMB 8633T (=LMG 2848T) and C. fulvus NCIMB 8634T (=LMG 2847T) are the proposed type strains.
Pseudoalteromonas arctica sp. nov., an aerobic, psychrotolerant, marine bacterium isolated from Spitzbergen.
Al Khudary, R., Stößer, N. I., Qoura, F. & Antranikian, G. (2008). International Journal of Systematic and Evolutionary Microbiology, 58(9), 2018-2024.
A novel aerobic, psychrotolerant marine bacterium was isolated at 4°C from seawater samples collected from Spitzbergen in the Arctic. The strain was a polar-flagellated, Gram-negative bacterium that grew optimally at 10–15°C and pH 7–8 in media containing 2–3 % NaCl (w/v), using various carbohydrates and organic acids as substrates. The main fatty acid components included 16 : 0 (12.7 % of total fatty acids), straight-chain saturated fatty acid methyl ester (FAME) and 16 : 1ω7c (40.2 %) monounsaturated FAME. Phylogenetic analysis revealed a close relationship (99 % 16S rRNA gene sequence similarity) between the novel isolate and Pseudoalteromonas elyakovii KMM 162T and some other species of the genus Pseudoalteromonas. The DNA G+C content of the novel strain was 39 mol%. DNA–DNA hybridization showed only 47.6 % DNA–DNA relatedness with P. elyakovii KMM 162T, 44.2 % with Pseudoalteromonas distincta KMM 638T and 22.6 % with Pseudoalteromonas nigrifaciens NCIMB 8614T Based on phylogenetic and phenotypic characteristics, this isolate represents a novel species of the genus Pseudoalteromonas for which the name Pseudoalteromonas arctica is proposed; the type strain is A 37-1-2T (=LMG 23753T=DSM 18437T).
Patterns of functional enzyme activity in fungus farming ambrosia beetles.
Licht, H. H. D. F. & Biedermann, P. H. (2012). Frontiers in Zoology, 9(1), 13.
Introduction: In wood-dwelling fungus-farming weevils, the so-called ambrosia beetles (Curculionidae: Scolytinae and Platypodinae), wood in the excavated tunnels is used as a medium for cultivating fungi by the combined action of digging larvae (which create more space for the fungi to grow) and of adults sowing and pruning the fungus. The beetles are obligately dependent on the fungus that provides essential vitamins, amino acids and sterols. However, to what extent microbial enzymes support fungus farming in ambrosia beetles is unknown. Here we measure (i) 13 plant cell-wall degrading enzymes in the fungus garden microbial consortium of the ambrosia beetle Xyleborinus saxesenii, including its primary fungal symbionts, in three compartments of laboratory maintained nests, at different time points after gallery foundation and (ii) four specific enzymes that may be either insect or microbially derived in X. saxesenii adult and larval individuals. Results: We discovered that the activity of cellulases in ambrosia fungus gardens is relatively small compared to the activities of other cellulolytic enzymes. Enzyme activity in all compartments of the garden was mainly directed towards hemicellulose carbohydrates such as xylan, glucomannan and callose. Hemicellulolytic enzyme activity within the brood chamber increased with gallery age, whereas irrespective of the age of the gallery, the highest overall enzyme activity were detected in the gallery dump material expelled by the beetles. Interestingly endo-β-1,3(4)-glucanase activity capable of callose degradation was identified in whole-body extracts of both larvae and adult X. saxesenii, whereas endo-β-1,4-xylanase activity was exclusively detected in larvae. Conclusion: Similar to closely related fungi associated with bark beetles in phloem, the microbial symbionts of ambrosia beetles hardly degrade cellulose. Instead, their enzyme activity is directed mainly towards comparatively more easily accessible hemicellulose components of the ray-parenchyma cells in the wood xylem. Furthermore, the detection of xylanolytic enzymes exclusively in larvae (which feed on fungus colonized wood) and not in adults (which feed only in fungi) indicates that only larvae (pre-) digest plant cell wall structures. This implies that in X. saxesenii and likely also in many other ambrosia beetles, adults and larvae do not compete for the same food within their nests - in contrast, larvae increase colony fitness by facilitating enzymatic wood degradation and fungus cultivation.
Evolutionary transitions in enzyme activity of ant fungus gardens.
De Fine Licht, H. H., Schiøtt, M., Mueller, U. G. & Boomsma, J. J. (2010). Evolution, 64(7), 2055-2069.
Fungus-growing (attine) ants and their fungal symbionts passed through several evolutionary transitions during their 50 million year old evolutionary history. The basal attine lineages often shifted between two main cultivar clades, whereas the derived higher-attine lineages maintained an association with a monophyletic clade of specialized symbionts. In conjunction with the transition to specialized symbionts, the ants advanced in colony size and social complexity. Here we provide a comparative study of the functional specialization in extracellular enzyme activities in fungus gardens across the attine phylogeny. We show that, relative to sister clades, gardens of higher-attine ants have enhanced activity of protein-digesting enzymes, whereas gardens of leaf-cutting ants also have increased activity of starch-digesting enzymes. However, the enzyme activities of lower-attine fungus gardens are targeted primarily toward partial degradation of plant cell walls, reflecting a plesiomorphic state of nondomesticated fungi. The enzyme profiles of the higher-attine and leaf-cutting gardens appear particularly suited to digest fresh plant materials and to access nutrients from live cells without major breakdown of cell walls. The adaptive significance of the lower-attine symbiont shifts remains unclear. One of these shifts was obligate, but digestive advantages remained ambiguous, whereas the other remained facultative despite providing greater digestive efficiency.
The use of plant cell wall degrading enzymes from a newly isolated Penicillium ochrochloron Biourge for viscosity reduction in ethanol production with fresh sweet potato tubers as feedstock.
Huang, Y., Jin, Y., Shen, W., Fang, Y., Zhang, G. & Zhao, H. (2014). Biotechnology and Applied Biochemistry, 61(4), 480-491.
Penicillium ochrochloron Biourge, which was isolated from rotten sweet potato, can produce plant cell wall degrading enzymes (PCWDEs) with high viscosity reducing capability for ethanol production using fresh sweet potato tubers as feedstock. The enzyme preparation was characterized by a broad enzyme spectrum including 13 kinds of enzymes with the activity to hydrolyze cellulose, hemicellulose, pectin, starch and protein. The maximum viscosity reducing capability was observed when the enzyme preparation was obtained after five days fermentation using 20 g/L corncob as sole carbon source, 4.5 g/L NH4NO3 as sole nitrogen source, and an initial medium pH of 6.5. The sweet potato mash treated with the enzyme preparation exhibited much higher fermentation efficiency (92.58%) compared with commercial cellulase (88.06%) and control (83.5%). The enzyme production was then scaled up to 0.5, 5, and 100 L, and the viscosity reducing rates were found to be 85%, 90%, and 91%, respectively. Thus, P. ochrochloron Biourge displays potential viscosity reducing capability for ethanol production.