Synthesis and conformational analysis of linear homo- and heterooligomers from novel 2-C-branched sugar amino acids (SAAs).

Sugar amino acids (SAAs), as biologically interesting structures bearing both amino and carboxylic acid functional groups represent an important class of multifunctional building blocks. In this study, we develop an easy access to novel SAAs in only three steps starting from nitro compounds in high yields in analytically pure form, easily available by ceric (IV) mediated radical additions. Such novel SAAs have been applied in the assembly of total nine carbopeptoids with the form of linear homo- and heterooligomers for the structural investigations employing circular dichroism (CD) spectroscopy, which suggest that the carbopeptoids emerge a well-extended, left (or right)-handed conformation similar to polyproline II (PPII) helices. NMR studies also clearly demonstrated the presence of ordered secondary structural elements. 2D-ROESY spectra were acquired to identify i+1 NH ↔ i C 1 H, i C 2 H correlations which support the conformational analysis of tetramers by CD spectroscopy. These findings provide interesting information of SAAs and their oligomers as potential scaffolds for discovering new drugs and materials.

Colwellia agarivorans sp. nov., an agar-digesting marine bacterium isolated from coastal seawater.

A novel Gram-stain-negative, facultatively anaerobic, yellowish and agar-digesting marine bacterium, designated strain QM50T, was isolated from coastal seawater in an aquaculture site near Qingdao, China. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the isolate represented a member of the genus Colwellia and exhibited the highest sequence similarity (97.4 %) to Colwellia aestuarii SMK-10T. Average nucleotide identity (ANI) values based on draft genome sequences between strain QM50T and C. aestuarii KCTC 12480T showed a relatedness of 72.0 % (ANIb) and 85.1 % (ANIm). Cells of strain QM50T were approximately 0.3-0.6×0.8-2.5 µm in size and motile by means of a polar flagellum. Growth occurred in the presence of 1.0-6.0 % (w/v) NaCl (optimum, 2.0-3.0 %), at pH 6.5-8.5 (optimum, pH 7.0) and at 4-37 °C (optimum, 28-30 °C). Strain QM50T was found to contain ubiquinone 8 (Q-8) as the predominant ubiquinone and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH), C16 : 0 and C17 : 1ω8c as the main cellular fatty acids. Phosphatidylethanolamine and phosphatidylglycerol were found to be major polar lipids. The DNA G+C content of strain QM50T was determined to be 35.7 mol%. On the basis of phylogenetic and phenotypic data, strain QM50T represents a novel species of the genus Colwellia, for which the name Colwellia agarivorans sp. nov. is proposed. The type strain is QM50T (=KCTC 52273T=MCCC 1H00143T).

Marinifilum albidiflavum sp. nov., isolated from coastal sediment.

A novel Gram-stain-negative, facultatively anaerobic, filamentous, and yellowish-white-pigmented marine bacterium, designated strain FB208T, was isolated from marine sediment obtained off the coastal area of Weihai, China. Cells of strain FB208T were filamentous during exponential growth, fragmented to rods in the stationary growth phase and became spherical in aged cultures. It grew optimally at 33 °C, at pH 7.0-7.5 and in the presence of 2.0-3.0 % (w/v) NaCl. Based on the 16S rRNA gene sequence, strain FB208T was found to be closely related to Marinifilum flexuosum DSM 21950T (96.9 % similarity) and Marinifilum fragile JCM 15579T (96.4 %), with less than 90.0 % sequence similarity to other genera of the class Bacteroidia. Phylogenetic analysis, also based on 16S rRNA gene sequences, placed strain FB208T in the genus Marinifilum, family Marinifilaceae. The predominant isoprenoid quinone of strain FB208T was identified as menaquinone MK-7. The main cellular fatty acids were iso-C15 : 0, iso-C17 : 0 3-OH and iso-C17 : 1ω9c, and the major polar lipids were an unidentified lipid and aminophospholipid. The G+C content of the genomic DNA was 43.8 mol%. Based on these phylogenetic and phenotypic data, strain FB208T represents a novel species of the genus Marinifilum, for which the name Marinifilum albidiflavum sp. nov. is proposed. The type strain is FB208T (=KCTC 42591T=MCCC 1H00113T).

Nocardioides gilvus sp. nov., isolated from Namtso Lake.

A Gram-stain positive, facultatively anaerobic, non-motile and rod to coccoid-shaped bacterium, designated XZ17(T), was isolated from Namtso Lake of Tibet, China. Strain XZ17(T) grew optimally at pH 8.0-9.0, at 30-33 °C and in the presence of 0-1.0 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences demonstrated that strain XZ17(T) belongs to the genus Nocardioides in the family Nocardioidaceae. Strain XZ17(T) shared pairwise 16S rRNA gene sequence similarities of 97.2, 96.8, 96.5, 96.4 and <96.0 % to Nocardioides solisilvae KCTC 39528(T), Nocardioides daejeonensis JCM 16922(T), Nocardioides jensenii NCIB 9770(T), Nocardioides dubius KCTC 9992(T) and other Nocardioides species, respectively. It contained MK-8 (H4) as the predominant menaquinone and C17:1 ω8c, C15:0, C17:0 and C18:1 ω9c as the major fatty acid. The strain had cell wall peptidoglycan based on LL-2,6-diaminopimelic acid. The polar lipids of strain XZ17(T) comprised diphosphatidylglycerol, phosphatidylglycerol, three unidentified phospholipids, three unidentified glycolipids and two unidentified lipids. The DNA G+C content of strain XZ17(T) was 68.9 mol%. Based on distinctive phenotypic characteristics, phylogenetic analysis and chemotaxonomic data, it can be concluded that strain XZ17(T) represents a novel species within the genus Nocardioides, for which the name Nocardioides gilvus sp. nov. is proposed. The type strain is strain XZ17(T) (=KCTC 39561(T) = MCCC 1H00114(T)).

Kordiimonas sediminis sp. nov., isolated from a sea cucumber culture pond.

A marine bacterium, designated strain N39(T), was isolated from a sediment sample collected at a sea cucumber culture pond in Weihai, China. Cells of strain N39(T) were observed to be Gram-stain negative, facultatively anaerobic, motile rods showing catalase and oxidase negative reactions. Strain N39(T) was found to grow optimally at pH 8.0-8.5, 35-37 °C and in the presence of approximately 3.0 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain N39(T) belongs to the genus Kordiimonas in the family Kordiimonadaceae, appearing closely related to Kordiimonas lacus JCM 16261(T) (95.9 %), Kordiimonas aquimaris MEBiC06554(T) (95.1 %), Kordiimonas gwangyangensis JCM 12864(T) (94.2 %) and Kordiimonas aestuarii 101-1(T) (93.8 %). Ubiquinone 10 (Q-10) was found to be the major respiratory quinone. The dominant cellular fatty acids were identified as iso-C17:1 ω9c, iso-C17:0, iso-C15:0 and C17:1 ω6c. The predominant polar lipids were found to be phosphatidylglycerol, phosphatidylethanolamine and diphosphatidylglycerol. The DNA G + C content of strain N39(T) is 50.8 %. On the basis of genotypic, chemotaxonomic and phenotypic data, strain N39(T) is concluded to represent a novel species within the genus Kordiimonas, for which the name Kordiimonas sediminis sp. nov. is proposed. The type strain is N39(T) (=KCTC 42590(T) = MCCC 1H00112(T)).