Effect of elevated atmospheric CO2 concentration on growth and leaf litter decomposition of Quercus acutissima and Fraxinus rhynchophylla.

The atmospheric carbon dioxide (CO2) level is expected to increase substantially, which may change the global climate and carbon dynamics in ecosystems. We examined the effects of an elevated atmospheric CO2 level on the growth of Quercus acutissima and Fraxinus rhynchophylla seedlings. We investigated changes in the chemical composition of leaf litter, as well as litter decomposition. Q. acutissima and F. rhynchophylla did not show differences in dry weight between ambient CO2 and enriched CO2 treatments, but they exhibited different patterns of carbon allocation, namely, lower shoot/root ratio (S/R) and decreased specific leaf area (SLA) under CO2-enriched conditions. The elevated CO2 concentration significantly reduced the nitrogen concentration in leaf litter while increasing lignin concentrations and carbon/nitrogen (C/N) and lignin/N ratios. The microbial biomass associated with decomposing Q. acutissima leaf litter was suppressed in CO2 enrichment chambers, while that of F. rhynchophylla was not. The leaf litter of Q. acutissima from the CO2-enriched chambers, in contrast with F. rhynchophylla, contained much lower nutrient concentrations than that of the litter in the ambient air chambers. Consequently, poorer litter quality suppressed decomposition.

Henriciella litoralis sp. nov., isolated from a tidal flat, transfer of Maribaculum marinum Lai et al. 2009 to the genus Henriciella as Henriciella aquimarina nom. nov. and emended description of the genus Henriciella.

A Gram-staining-negative, strictly aerobic bacterium, designated strain SD10(T), was isolated from a tidal flat of the Yellow Sea, South Korea. Cells were non-spore-forming rods that showed catalase- and oxidase-positive reactions. Growth of strain SD10(T) was observed at 15-40 °C (optimum, 25-30 °C), at pH 6.0-9.0 (optimum, pH 6.5-8.5) and in the presence of 1-10 % (w/v) NaCl. Strain SD10(T) contained ubiquinone-10 (Q-10) as a major isoprenoid quinone and C(18 : 1)ω7c (39.3 %), C(16 : 0) (20.2 %), C(17 : 0) (8.9 %) and C(17 : 1)ω6c (8.1 %) as major fatty acids. The cellular polar lipids were identified as phosphatidylglycerol, monoglycosyldiglyceride, glucuronopyranosyldiglyceride and two unidentified glycolipids. The G+C content of the genomic DNA was 55.2 mol%. Based on 16S rRNA gene sequence similarities, the strain was most closely related to Henriciella marina Iso4(T) and Maribaculum marinum P38(T), with similarities of 97.8 and 97.0 %, respectively. The DNA-DNA relatedness between strain SD10(T) and H. marina Iso4(T) was 12.0±3.2 %. A phylogenetic analysis based on 16S rRNA gene sequences showed that M. marinum P38(T) and H. marina Iso4(T) formed a monophyletic cluster and that their 16S rRNA gene sequence similarity was 98.1 %. DNA-DNA hybridization between H. marina Iso4(T) and M. marinum LMG 24711(T) was 22.9±2.7 %, indicating that the two strains belong to separate species. On the basis of chemotaxonomic data and molecular properties, we propose that strain SD10(T) represents a novel species of the genus Henriciella, for which the name Henriciella litoralis sp. nov. is proposed. The type strain is SD10(T) ( = KACC 13700(T)  = DSM 22014(T)). In addition, we propose to transfer Maribaculum marinum Lai et al. 2009 to the genus Henriciella as Henriciella aquimarina nom. nov. (type strain P38(T)  = CCTCC AB 208227(T)  = LMG 24711(T)  = MCCC 1A01086(T)), and we present an emended description of the genus Henriciella.

Characterization of EamaT1, a member of maT family of transposable elements from the earthworm Eisenia andrei (Annelida, Oligochaeta).

The maT family is a unique clade within the Tc1-mariner superfamily, and their distribution is to date known as being limited to invertebrates. A novel transposon named EamaT1 is described from the genome of the earthworm Eisenia andrei. The full sized EamaT1 was obtained by degenerate and inverse PCR-based amplification. Sequence analysis of multiple copies of the EamaT1, which consisted of 0.9 and 1.4 kb elements, showed that the consensual EamaT1 with inverted terminal repeats (ITRs) of 69 bp was 1,422 bp long and flanked by a duplicated TA dinucleotide. The EamaT1 is present in approximately 120-250 copies per diploid genome but undergoes an inactivation process as a result of accumulating multiple mutations and is nonfunctional. The open reading frame (ORF) of the EamaT1 consensus encoding 356 amino acid sequences of transposase contained a DD37D signature and a conserved paired-like DNA binding motif for the transposition mechanism. The result of ITRs comparison confirmed their consensus terminal sequences (5'-CAGGGTG-3') and AT-rich region on the internal bases for ITRs-transposase interaction.