Bioscience

First Plant Microbiota Metagenome Bank

With three years’ efforts, Prof. Zeng Ying and her colleagues from Kunming Institute of Botany have recently first established a plant microbiota metagenome bank through independent innovation in the enrichment for plant microbiota. For microbes including a large number of plant microbiota that have not been successfully cultured, their genetic resources can be exploited using metagenome research strategy, so as to offer an opportunity to make significant results in medical, industrial biotechnological and other areas. Relevant achievements of this research were published on Journal of Applied Microbiology and Environmental Microbiology.
The metagenome bank established has great potential for future study and exploitation. It not only has a large capacity (1.37×106 clones, equivalent to 5,000 copies of streptomyces genome), but also contains a variety of microbes. The genomes in the bank cover seven phyla and over 200 species of microbes, particularly actinomycetes and proteobacteria, of which a large portion are microbes that can not be cultured or sources of new species.

Eco-rehabilitation Calls for Urgent Action

Recently, Nature carried an article entitled “Where the rubber meets the garden” to report the protection efforts of Xishuanbanna Tropical Botanical Garden, CAS in the tropical region. XTBG was established at a forest-surrounded tropical area in south Yunnan in 1959. The 900-hectare garden is renowned for its exceptional beauty and has a collection of 11,700 plant species. It has made positive contributions to the species introduction, conservation and sustainable utilization of economic plants, including natural rubber.
However, over the past decade, due to sharp increase of rubber price, the rubber plantation at Xishuanbanna has been expanded so rapidly. Now, XTBG is almost surrounded by a big labyrinth of rubber plantation. The article quoted the field survey data published by XTBG, in which relevant remote sensing research revealed that during 1976-2003, the forest area was decreased by 14,000 hectares annually. Now the forest coverage has been reduced to less than 50%, while the area of pristine tropical rainforest has been reduced to less than 3.6%. Facing the actual picture that profits from rubber plantations (15,000 RMB yuan /hectare) are far more than that from the padded fields and tea plantations (2,000-3,000 RMB yuan /hectare). However, XTBG is trying all means to change the eco-picture in this area, which have attracted serious international concern. But we may foresee that any protection endeavor in this area might encounter great challenges: sustainable eco-conservation or economic development, and/or how to balance the two.-3

A New Survival Mechanism of HBV-infected Cells

Arecent issue of Hepatology published the latest findings by Zhao Mujun Research Team of the Institute of Biochemistry and Cell Biology, Shanghai Institutes of Biological Sciences, CAS: Hepatitis B virus X protein (HBx) sensitizes cells to starvation-induced autophagy via upregulation of beclin 1 expression.

Dr. Tang Hong, together with other colleagues from Zhao Mujun Research Team, found a new function of HBx, that is, in regulating the autophagy of host cells. Aautophagy is a cellular self-eating process by which cells recycle cytoplasm and dispose excess or defective organelles. During starvation, autophagy is a cell-defense mechanism by which amino acids and other intracellular nutrients are recycled to maintain cell survival. Human beclin 1 gene is the first identified mammalian gene to induce autophagy. The Research Team found that human beclin 1 is over-expressed in HBV-infected liver cancerous tissues. After introduction of HBx into hepatic or hepatoma cell lines, they found that expression of HBx results in the up-regulation of endogenous Beclin1 levels in tested cells. Then, they identified the promoter region of beclin 1gene and demonstrated that HBx can enhance the beclin 1promoter activity, therefore, increase the level of beclin 1 protein in cells. Beclin 1 is one of key molecules in autophagy. It forms a complex with ClassⅢ PI3K and advances the forming of early augophagic membrane structure. Further investigations showed HBx sensitizes cells to starvation-induced autophagy via upregulation of beclin 1 expression. Study on HBV positive hepatic cells also showed that HBV infection enhances autophagy of host cells. This is what HBx depends on. The above results of research suggest a possible survival mechanism of HBV infected hepatocytes under nutrient-deficient conditions and provide a new concept for the study on HBV infection and liver tumorigenesis.