Methylobacterium radiodurans sp. nov., a novel radiation-resistant Methylobacterium.

A Gram-negative, aerobic, flagellated, rod-shaped, and pink-pigmented bacterium, strain 17Sr1-43 T, was isolated from a soil sample collected in Nowongu, Seoul, Korea. The isolate could grow at 18-37 °C (optimum, 28-30 °C), pH 6.0-8.0 (optimum, pH 7.0) and in the presence of 0-1.0% (w/v) NaCl (optimum, 0%) with aeration. The major cellular fatty acids were summed feature 8 (C18:1 ω7c and/or C18:1 ω6c) and summed feature 2 (iso-C16:1 I and/or C14:0 3-OH). The predominant respiratory quinone was Q-10 and the major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, phospholipid, and diphosphatidylglycerol. The G + C content of genomic DNA was 69.1 mol%. Strain 17Sr1-43 T was closely related to Methylobacterium gregans KACC 14808 T (98.4% 16S rRNA gene sequence similarity), Methylobacterium hispanicum KACC 11432 T (97.9%), and Methylobacterium phyllosphaerae CBMB27T (96.1%). The complete genome of strain 17Sr1-43 T contains essential genes related to DNA repair processes including bacterial RecBCD dependent pathway and UmuCD system. Based on the phenotypic, genotypic, and chemotaxonomic characteristics, strain 17Sr1-43 T represents a novel species in the genus Methylobacterium, for which the name Methylobacterium radiodurans sp. nov. is proposed. The type strain is strain 17Sr1-43 T (= KCTC 52906 T = NBRC 112875 T).

Complete genome sequence of Hymenobacter swuensis, an ionizing-radiation resistant bacterium isolated from mountain soil.

Hymenobacter swuensis is a gamma-radiation resistant bacterium isolated from mountain soil in South Korea (N 35°51'38″, E 127°44'47″; altitude 1500m). The complete genome of H. swuensis consists of one chromosome (4,904,241bp) with three plasmids. The genomic sequence indicated that H. swuensis includes a series of genes involved in 2'-hydroxy-carotenoid biosynthesis. This is the first report describing the Hymenobacter genome and key enzymes in the 2'-hydroxy-carotenoid biosynthesis pathway. These data may provide opportunities for genetic engineering and antioxidant 2'-hydroxy-carotenoid production.

Isolation and expression analysis of a novel major latex-like protein (MLP151) gene from Panax ginseng.

This is the first reports on isolation and expression analysis of a major latex-like protein (MLP151) gene in Panax ginseng C.A. Meyer. A full-length cDNA of MLP151 was 850 bp and contained a 456 bp open reading frame encoding a polypeptide of 151 amino acids. A theoretical pI value of MLP151 was 4.86 and calculated molecular weight was about 16.87 kDa. The MLP homolog proteins are found in various plants and the neighbor-joining analysis revealed that MLP151 has the closest distance with Sn-1 (bell pepper, MLP homolog gene). We analyzed the expression of MLP151 in different levels in various organs of ginseng and plantlet. In the result, the gene was low expressed in plantlet. We treated the ginseng plantlets with nine kinds of different stresses and analyzed the expression profile of MLP151. Transcript levels were significantly induced by stress treatment of light and mannitol, whereas transcript levels were drastically decreased in dark, H(2)O(2), salicylic acid and wounding samples.

Pedobacter agri sp. nov., from soil.

A Gram-negative strain, PB92(T), which belongs to the family Sphingobacteriaceae, was isolated from soil (Daejeon, Korea). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain PB92(T) was associated with the genus Pedobacter and was most closely related to the type strains Pedobacter sandarakinus DS-27(T) (97.7 %), Pedobacter roseus CL-GP80(T) (97.5 %) and Pedobacter suwonensis 15-52(T) (97.5 %). The major cellular fatty acid components of strain PB92(T) were C(16 : 1)omega7c (21.4 %), iso-C(15 : 0) (30.8 %), iso-C(17 : 0) 3-OH (9.3 %) and iso-C(15 : 0) 2-OH (11.2 %). The G+C content of the genomic DNA from strain PB92(T) was 41.4 mol%. Analysis of 16S rRNA gene sequences, as well as physiological and biochemical tests, indicated that strain PB92(T) could be differentiated genotypically and phenotypically from reference species of the genus Pedobacter. Strain PB92(T) (=KCTC 12511(T)=DSM 19486(T)) is proposed as the type strain of a novel species, Pedobacter agri sp. nov.

Chryseobacterium caeni sp. nov., isolated from bioreactor sludge.

A Gram-negative, non-spore-forming, yellow-pigmented bacterium, strain N4(T), was isolated from a nickel-complexed cyanide-degrading bioreactor and subjected to a polyphasic taxonomic study. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain N4(T) is affiliated to the genus Chryseobacterium of the family Flavobacteriaceae. The levels of 16S rRNA gene sequence similarity between strain N4(T) and the type strains of all known Chryseobacterium species were 93.2-95.8 %, suggesting that strain N4(T) represents a novel species within the genus Chryseobacterium. The strain contained iso-C(15 : 0) and summed feature 4 as the major fatty acids and menaquinone MK-6 as the predominant respiratory quinone. The G+C content of the genomic DNA was 38.2 mol%. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain N4(T) represents a novel species of the genus Chryseobacterium, for which the name Chryseobacterium caeni sp. nov. is proposed. The type strain is N4(T) (=KCTC 12506(T)=CCBAU 10201(T)=DSM 17710(T)).

Development of a plate technique for screening of polysaccharide-degrading microorganisms by using a mixture of insoluble chromogenic substrates.

A plate assay based on the visible solubilization of small substrate particles and the formation of haloes on Petri dishes, containing a mixture of different dye-labelled polysaccharides as substrates, provides a specific, reliable and rapid simultaneous detection of corresponding polysaccharide-degrading microorganisms. It has potential for increasing the efficacy of screening of microorganisms, utilizing different polysaccharides, in large numbers of natural samples. Diversely colored insoluble forms of amylose, xylan and hydroxyethyl-cellulose (HE-cellulose) were prepared as chromogenic substrates by using the cross-linking reagent 1,4-butanediol diglycidyl ether and the dyes Brilliant Red 3B-A, Cibacron Blue 3GA and Reactive Orange 14. Using the method, the bacteria with amylase or xylanase or cellulase or a combination of these activities were screened from soil and sludge samples, selected and identified according to 16S rDNA sequencing.

Kaistia adipata gen. nov., sp. nov., a novel alpha-proteobacterium.

A taxonomic study was carried out on Chj404T, a bacterial strain isolated from a soil sample collected in an industrial stream near the Chung-Ju industrial complex in Korea. The strain was a gram-negative, aerobic, short rod to coccus-shaped bacterium. It grew well on nutrient agar medium and utilized a broad spectrum of carbon sources. The G+C content of the DNA was 67.4 mol% and the major composition of ubiquinone was Q-10. The major fatty acid was C18:1. Comparative 16S rDNA studies showed a clear affiliation of this bacterium to alpha-Proteobacteria. Comparison of phylogenetic data indicated that it was most closely related to Prosthecomicrobium pneumaticum (92.7% similarity in 16S rDNA sequence). Since strain Chj404 is clearly distinct from closely related species, we propose the name Kaistia adipata gen. nov., sp. nov. for this strain Chj404T (=IAM 15023T=KCTC 12095T).