Seedling growth and soil nutrient availability in exotic and native tree species: implications for afforestation in southern China

Background and aims

The relationship between tree species and soil nutrient availability is critical for evaluating plantation succession and promoting forest restoration. This study was conducted to evaluate the impact of exotic and native tress species on soil nutrient availability.

Methods

Four exotic species (Eucalyptus urophylla, E. tereticornis, Acaia auriculaeformis, A. mangium) and four native species (Castanopsis fissa, Schima superba, C. hystrix, Michelia macclurei) were planted and grown for one-year. Soil solution (DOC, DON, NH₄?N, NO₃?N) was sampled and analyzed during the study. After the experiment, soil properties were determined, and plant tissues were analyzed.

Results

DOC levels were greater in soils with trees planted than controls without trees. Compared to native species, exotic species had much faster growth rates and greatly reduced DON and NO₃?N concentrations. Exotic species always had less P concentrations in leaves and stems than native species. Furthermore, N-fixing A. auriculaeformis led to greater soil available P compared to other species.

Conclusions

Based on these findings, we provide some recommendations for afforestation practice. This study highlights that a better understanding of the pros and cons of exotic species would be beneficial to advance afforestation in China and the world.     

Analysis of Fecal Lactobacillus Community Structure in Patients with Early Rheumatoid Arthritis

The objective of this study was to analyze human fecal Lactobacillus community and its relationship with rheumatoid arthritis. Samples taken from rheumatoid arthritis (RA) patients and healthy individuals were analyzed by quantitative real-time PCR. Bacterial DNA was extracted from feces, and amplicons of the Lactobacillus-specific regions of 16S rRNA were analyzed by denaturing gradient gel electrophoresis. The richness, Shannon-Wiener index, and evenness of gut microbiota of both groups were analyzed to compare fecal Lactobacillus community structures. Results of this study demonstrated that fecal microbiota of RA patients contained significantly more Lactobacillus (10.62 ± 1.72 copies/g) than the control group (8.93 ± 1.60 copies/g). Significant increases were observed in RA patients in terms of the richness, Shannon-Wiener, and evenness measures, indicating more bacterial species, and increased bacterial diversity and abundance. These results suggest a potential relationship between Lactobacillus communities and the development and progression of rheumatoid arthritis.     

Precursor engineering and cell physiological regulation for high level rapamycin production by Streptomyces hygroscopicus

A process for high level production of rapamycin by Streptomyces hygroscopicus using statistical designs and feeding strategy was developed. The amino acids (i.e. Lys, Tyr, and Gln) for precursor supply were screened out in the initial phase of fermentation. The optimum levels determined with Box-Behnken design were Lys 20, Tyr 4, and Gln 3 g/l. In the rapamycin biosynthesis phase, the important component, ammonium sulphate, was also identified. A novel two-stage feeding strategy was developed successfully to increase the flux of rapamycin biosynthesis, in which the optimized amino acid components were fed in the initial phase of fermentation, and then switched to feed 2 g/l ammonium sulphate at 72 h. The maximal rapamycin production reached 860.6 mg/l in a 7 l fermentor, which was 182 % higher than that of the control. This was the first report to integrate precursor engineering and cell physiological regulation methods to optimize rapamycin production.     

Law of the Sea Issues Between the United States and East Asian States

The United States is the sole superpower in the contemporary world and its role in the development of the law of the sea cannot be ignored. Although having not yet acceded to the U.N. Convention on the Law of the Sea, the United States has contributed to the development of the international law of the sea in numerous ways, including responding to the so-called excessive maritime claims in East Asia and creating new rules of maritime enforcement. This article assesses this recent U.S. practice.     

LncRNA OIP5-AS1 regulates radioresistance by targeting DYRK1A through miR-369-3p in colorectal cancer cells

Object

This study aimed to investigate the role of lncRNA OIP5-AS1 in regulating radioresistance of colorectal cancer (CRC) cells.

miR-3133 inhibits gastrointestinal cancer progression through activation of Hippo and p53 signalling pathways via multi-targets

Background

Malignant cell growth and chemoresistance, the main obstacles in treating gastrointestinal cancer (GIC), rely on the Hippo and p53 signalling pathways. However, the upstream regulatory mechanisms of these pathways remain complex and poorly understood.

Methods

Immunohistochemistry (IHC), western blot and RT-qPCR were used to analyse the expression of RNF146, miR-3133 and key components of Hippo and p53 pathway. CCK-8, colony formation, drug sensitivity assays and murine xenograft models were used to investigate the effect of RNF146 and miR-3133 in GIC. Further exploration of the upstream regulatory mechanism was performed using bioinformatics analysis, dual-luciferase reporter gene, immunoprecipitation assays and bisulfite sequencing PCR (BSP).

Results

Clinical samples, in vitro and in vivo experiments demonstrated that RNF146 exerts oncogenic effects in GIC by regulating the Hippo pathway. Bioinformatics analysis identified a novel miRNA, miR-3133, as an upstream regulatory factor of RNF146. fluorescence in situ hybridization and RT-qPCR assays revealed that miR-3133 was less expressed in gastrointestinal tumour tissues and was associated with adverse pathological features. Functional assays and animal models showed that miR-3133 promoted the proliferation and chemotherapy sensitivity of GIC cells. miR-3133 affected YAP1 protein expression by targeting RNF146, AGK and CUL4A, thus activating the Hippo pathway. miR-3133 inhibited p53 protein degradation and extended p53's half-life by targeting USP15, SPIN1. BSP experiments confirmed that miR-3133 promoter methylation is an important reason for its low expression.

Conclusion

miR-3133 inhibits GIC progression by activating the Hippo and p53 signalling pathways via multi-targets, including RNF146, thereby providing prognostic factors and valuable potential therapeutic targets for GIC.     

Characteristics of an anaerobic, syntrophic, butyrate-degrading bacterium in paddy field soil

The number of syntrophic butyrate-degrading bacteria in a flooded paddy field soil was 1.7 x 10(3) MPN/g dry soil. Butyrate was degraded to acetate and methane when paddy soils were incubated anaerobically with the addition of butyrate. However, butyrate degradation was completely suppressed by the addition of the specific inhibitor of methanogenesis, 2-bromoethanesulfonate (BES) to the soil. A hydrogen-using methanogen, strain TM-8, was isolated from flooded paddy field soil. Strain TM-8 was identified as Methanobacterium formicicum based on its physiology and phylogeny. Syntrophic butyrate-degrading bacteria were enumerated and isolated using strain TM-8. A syntrophic butyrate-degrading bacterium, strain TB-6, was isolated in coculture with strain TM-8 from paddy soil. The strain was Gram-negative, had curved rods, and grew on crotonate. Sulfate was not used as an electron acceptor. Strain TB-6 was closely related to S. wolfei subsp. wolfei. The relation between strain TB-6 and the members of Syntrophomonas are discussed.