Complete genome sequence of a marine bacterium with two chromosomes, Pseudoalteromonas translucida KMM 520(T).

Bacteria with multiple chromosomes provide new insights into the evolution of multipartite genome structures and bacterial survival strategies. In this study, we report the complete genome sequence of Pseudoalteromonas translucida KMM 520(T), which contains two circular chromosomes and comprises 4,147,593 bp with a mean G+C content of 40.1%. The two chromosomes have similar G+C contents and similar percentages of coding regions. Chromosome II of P. translucida possesses a plasmid-type replication initiator protein (RepA), which indicated that chromosome II is probably originated from a plasmid. COG functional categories revealed that the two chromosomes have divergent distributions of functional categories, which indicated that they bear different responsibilities for cellular functions. The complete genome sequence of P. translucida contributes to a better understanding of the origin and evolution of the additional chromosome and the physiology of Pseudoalteromonas genus.

Insight into the genome sequence of a sediment-adapted marine bacterium Neptunomonas antarctica S3-22(T) from Antarctica.

Neptunomonas antarctica S3-22(T) was isolated from marine sediment of the Nella Fjord, Antarctica. Here we report the draft genome sequence of N. antarctica, which comprises 4,568,828 bp with a mean G+C content of 45.7%. We found numerous genes related to resistance, motility and chemotaxis, nitrogen metabolism, aromatic compound metabolism and stress response. These metabolic features and related genes revealed genetic basis for the adaptation to the marine sediment environment in Antarctica. The genome sequence of N. antarctica S3-22(T) may also provide further insights into the ecological role of the genus Neptunomonas.

[Effect of timber moisture content and terrain conditions on the decay degree of Korean pine live standing trees].

Vast loss of timber resources can be reduced by preventing and controlling the decay of standing trees in forest management. Therefore, research concerning the effect of site conditions on decay of standing trees is particularly important for decay prevention and cure. A relevant study was carried out in Xiaoxing'anling Mountains on October, 2013, and thirty decayed and ten normal mature or postmature Korean pine (Pinus koraiensis) live standing trees were selected as sample trees, respectively. Two increment core samples were selected from the basal trunk of each sample tree to measure the mass loss ratio of rotted increment core samples. Meanwhile, moisture content of the soil near sample trees' roots and the gradient, exposure, slope position and elevation of the site where sample trees located were tested or measured. Analysis was made upon the relationship between factors such as sapwood and heartwood moisture contents and the decay of sample trees by correlation analysis and analysis of variance. The results indicated that moisture content of the sapwood negatively correlated with the decay degree of Korean pine live standing trees at a very significant level, so did the heartwood moisture content. Soil moisture content had a positive correlation with the decay degree at a highly significant level. Significant differences in the moisture contents of sapwood, heartwood and soils were observed between decayed and normal sample trees. Slope position was the only factor that had a significant effect on the decay degree among all the three slope factors. The decay degree of live standing trees on the middle part of slopes was significantly higher than that on the upper part of slope, mainly due to the significantly higher soil moisture content on the middle part of slope. Elevation of the site where sample trees located had no significant correlation with the decay degree of Korean pine.

[Correlations between standing trees trunk decay degree and soil physical-chemical properties in Korean pine-broadleaved mixed forest in Xiao Xing'an Mountains of Northeast China].

Standing trees decay often causes vast loss of timber resources. To investigate the correlations between the standing trees decay and the site conditions is of importance to scientifically and reasonably manage forests and to decrease wood resources loss. By using Resistograph and meter ruler, a measurement was made on the decay degree of the trunk near root and the diameter at breast height (DBH) of 15 mature Korean pine standing trees in a Korean pine-broadleaved mixed forest in Xiao Xing' an Mountains in May, 2011. In the meantime, soil samples were collected from the root zones of standing trees and the upslope and downslope 5 meters away from the trunks, respectively. Five physical-chemical properties including moisture content, bulk density, total porosity, pH value, and organic matter content of the soil samples were tested. The regression equations concerning the trunk decay degree of the standing trees, their DBH, and the 5 soil properties were established. The results showed that the trunk decay degree of the mature Korean pine standing trees had higher correlations with the bulk density, total porosity, pH value, and organic matter content (R = 0.687), and significant positive correlation with the moisture content (R = 0.507) of the soils at the root zones of standing trees, but less correlation with the 5 properties of the soils at both upslope and downslope 5 meters away from the trunks. The trunk decay degree was decreased when the soil moisture content was below 18.4%. No significant correlation was observed between the trunk decay degree of mature Korean pine standing trees and the tree age.