Yingnan Fu

The Fate of Marine Bacterial Exopolysaccharide in Natural Marine Microbial Communities

Most marine bacteria produce exopolysaccharides (EPS), and bacterial EPS represent an important source of dissolved organic carbon in marine ecosystems. It was proposed that bacterial EPS rich in uronic acid is resistant to mineralization by microbes and thus has a long residence time in global oceans. To confirm this hypothesis, bacterial EPS rich in galacturonic acid was isolated from Alteromonas sp. JL2810. The EPS was used to amend natural seawater to investigate the bioavailability of this EPS by native populations, in the presence and absence of ammonium and phosphate amendment. The data indicated that the bacterial EPS could not be completely consumed during the cultivation period and that the bioavailability of EPS was not only determined by its intrinsic properties, but was also determined by other factors such as the availability of inorganic nutrients. During the experiment, the humic-like component of fluorescent dissolved organic matter (FDOM) was freshly produced. Bacterial community structure analysis indicated that the class Flavobacteria of the phylum Bacteroidetes was the major contributor for the utilization of EPS. This report is the first to indicate that Flavobacteria are a major contributor to bacterial EPS degradation. The fraction of EPS that could not be completely utilized and the FDOM (e.g., humic acid-like substances) produced de novo may be refractory and may contribute to the carbon storage in the oceans.

Oceanitalea nanhaiensis gen nov, sp nov, an actinobacterium isolated from seawater

A Gram-positive, motile, short-rod-shaped bacterium, designated strain JLT1488(T), was isolated from the South China Sea and investigated in a taxonomic study using a polyphasic approach. The peptidoglycan type determined for strain JLT1488(T) was A4α with lysine as the diagnostic cell-wall diamino acid and an interpeptide bridge of L-Lys-L-Glu. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannosides, an unknown glycolipid and an unknown phospholipid. The only detected menaquinone was MK-8(H(4)), and the major fatty acids were summed feature 8 (C(18 : 1)ω7c/C(18 : 1)ω6c) , C(16 : 0) and summed feature 3 (C(16 : 1)ω7c/C(16 : 1)ω6c); significant amounts of C(12 : 0) 3-OH, C(10 : 0) and C(19 : 0) cyclo ω8c were also present. The G+C content of the genomic DNA was 62.3 mol%. Comparison of the 16S rRNA gene sequence of strain JLT1488(T) with those of related type strains demonstrated that it represented a novel lineage within the family Bogoriellaceae, suborder Micrococcineae, being closely related to species of the genera Georgenia, Bogoriella and Cellulomonas (94.6-96.8 % sequence similarity). These results demonstrate that strain JLT1488(T) is a member of a new genus, for which the name Oceanitalea nanhaiensis gen. nov., sp. nov. is proposed. The type strain of the type species is JLT1488(T) ( = JCM 17755(T) = CGMCC 1.10826(T)).

A Novel Exopolysaccharide with Metal Adsorption Capacity Produced by a Marine Bacterium Alteromonas sp. JL2810

Most marine bacteria can produce exopolysaccharides (EPS). However, very few structures of EPS produced by marine bacteria have been determined. The characterization of EPS structure is important for the elucidation of their biological functions and ecological roles. In this study, the structure of EPS produced by a marine bacterium, Alteromonas sp. JL2810, was characterized, and the biosorption of the EPS for heavy metals Cu2+, Ni2+, and Cr6+ was also investigated. Nuclear magnetic resonance (NMR) analysis indicated that the JL2810 EPS have a novel structure consisting of the repeating unit of [-3)-α-Rhap-(1→3)-α-Manp-(1→4)-α-3OAc-GalAp-(1→]. The biosorption of the EPS for heavy metals was affected by a medium pH; the maximum biosorption capacities for Cu2+ and Ni2+ were 140.8 ± 8.2 mg/g and 226.3 ± 3.3 mg/g at pH 5.0; however, for Cr6+ it was 215.2 ± 5.1 mg/g at pH 5.5. Infrared spectrometry analysis demonstrated that the groups of O-H, C=O, and C-O-C were the main function groups for the adsorption of JL2810 EPS with the heavy metals. The adsorption equilibrium of JL2810 EPS for Ni2+ was further analyzed, and the equilibrium data could be better represented by the Langmuir isotherm model. The novel EPS could be potentially used in industrial applications as a novel bio-resource for the removal of heavy metals.

Complete Genome Sequence of the d-Amino Acid Catabolism Bacterium Phaeobacter sp. Strain JL2886, Isolated from Deep Seawater of the South China Sea

ABSTRACT Phaeobacter sp. strain JL2886, isolated from deep seawater of the South China Sea, can catabolize d-amino acids. Here, we report the complete genome sequence of Phaeobacter sp. JL2886. It comprises ~4.06 Mbp, with a G+C content of 61.52%. A total of 3,913 protein-coding genes and 10 genes related to d-amino acid catabolism were obtained.

Erratum to: Coralslurrinella hongkonensis gen. nov., sp. nov., a novel bacterium in the family Psychromonadaceae, isolated from the coral Platygyra carnosus (Antonie van Leeuwenhoek, International Journal of General and Molecular Microbiology (2013) 104, (983-991) DOI: 10.1007/s10482-013-0017-z)

Subsequent to the publication of the above paper it has been brought to our attention that the name proposed for the taxon represented by strain JLT2006 T is problematic for several reasons. Consequently we here propose a corrected name for the taxon represented by strain JLT2006 T , which we propose be renamed as Corallincola platygyrae. The description of the genus is as given for Coral-slurrinella in Li et al. (2013) Antonie van Leeuwenhoek 104:983–991. The type species is Corallincola platygyrae.

Draft Genome Sequence of the Novel Exopolysaccharide-Producing Bacterium Altibacter lentus Strain JLT2010T, Isolated from Deep Seawater of the South China Sea

ABSTRACT Altibacter lentus strain JLT2010T is the type strain of the recently identified novel genus and species of the family Flavobacteriaceae and was first isolated from deep seawater of the South China Sea. It can produce exopolysaccharide. Here we report the first draft genome of JLT2010T (3,160,033 bp, with GC content of 42.12%) and major findings from its annotation. It is the first reported genome in the genus Altibacter.