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"Yang, Shi-Zhong"
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هذه هي الصين : قوة تسير نحو العالم
يركز كتاب \"هذه هي الصين\" على سرد قصص تنمية الصين في العصر الجديد. وقد غير الدكتور تشانغ وي وي طريقته المعروفة بالتوجيه والإرشاد في البرامج الأيديولوجية والنظرية في الماضي، وعبر عنها بلغة شعبية سائغة، وحجج منطقية صارمة، وبيانات حقيقية، وتصادمات صريحة للأفكار، وتقنيات عرض مبتكرة لمساعدة الجمهور على فهم النموذج الصيني والطريق الصيني، وتعزيز ثقتهم بمستقبل الصين.
Book
Anaerobic hydrocarbon degradation in candidate phylum ‘Atribacteria’ (JS1) inferred from genomics
The hydrocarbon-enriched environments, such as oil reservoirs and oil sands tailings ponds, contain a broad diversity of uncultured microorganisms. Despite being one of the few prokaryotic lineages that is consistently detected in both production water from oil reservoirs and stable hydrocarbon-degrading enrichment cultures originated from oil reservoirs, the physiological and ecological roles of candidate phylum “Atribacteria” (OP9/JS1) are not known in deep subsurface environments. Here, we report the expanded metabolic capabilities of Atribacteria as inferred from genomic reconstructions. Seventeen newly assembled medium-to-high-quality metagenomic assembly genomes (MAGs) were obtained either from co-assembly of two metagenomes from an Alaska North Slope oil reservoir or from previous studies of metagenomes coming from different environments. These MAGs comprise three currently known genus-level lineages and four novel genus-level groups of OP9 and JS1, which expands the genomic coverage of the major lineages within the candidate phylum Atribacteria. Genes involved in anaerobic hydrocarbon degradation were found in seven MAGs associated with hydrocarbon-enriched environments, and suggest that some Atribacteria could ferment short-chain
n
-alkanes into fatty acid while conserving energy. This study expands predicted metabolic capabilities of Atribacteria (JS1) and suggests that they are mediating a key role in subsurface carbon cycling.
Journal Article
أفكار حول تعميق الإصلاح
يناقش الكتاب سلسلة من الإيضاحات الهامة قدمها الرئيس الصيني والأمين العام للجنة المركزية للحزب الشيوعي الصيني، شي جين بينغ، وتدور حول أفكار الإصلاح وتوسيع الانفتاح على نحو شامل في الصين. يضم الكتاب أكثر من 70 وثيقة هامة على صورة كلمات شي جين بينغ وخطاباته وتعليقاته وتوجيهاته وينقسم الكتاب إلى 12 موضوعا خاصا تتضمن 274 قطعة من مقتطفات الأقوال، نشر بعضها لأول مرة.
Book
The Metabolic and Physiological Responses to Spaceflight of a Lipopeptide‐Producing Bacillus subtilis
Outer space is an extreme environment and the survival of many microorganisms after spaceflight is well established. However, adaptations of Bacillus subtilis to space stress, particularly metabolism, are largely unknown. Here, we first performed a spaceflight mission of the B. subtilis TD7 strain and compared the spaceflight‐exposed strain with the wild‐type in terms of their phenotype, biofilm formation and secondary metabolism. The spaceflight‐exposed strain exhibited slower growth, different morphology and decreased biofilm formation. Importantly, a decline in lipopeptide production was observed after spaceflight. Multi‐omics approaches were used to uncover the molecular mechanisms underlying secondary metabolism and 997 differentially expressed genes (DEGs) were found, involving the TCA cycle, fatty acid degradation, amino acid biosynthesis and quorum sensing systems. Further analysis of 26 lipopeptide‐related DEGs further elucidated the relationship between the space environment and secondary metabolism regulation. Our findings could contribute to a better understanding of the relationship between the space environment and microbial adaptation mechanisms. In this study, we performed a spaceflight experiment with B. subtilis TD7 strain, and findings showed that spaceflight resulted in slower growth, higher cell density, different morphology, decreased biofilm formation and lipopeptide metabolism. Transcriptomic analysis indicated that these lipopeptide changes were related to the upregulated genes in fatty acid degradation and TCA cycle, as well as downregulated genes in surfactin biosynthesis, valine, leucine and isoleucine biosynthesis.
Journal Article
Microbial Lipopeptide-Producing Strains and Their Metabolic Roles under Anaerobic Conditions
The lipopeptide produced by microorganisms is one of the representative biosurfactants and is characterized as a series of structural analogues of different families. Thirty-four families covering about 300 lipopeptide compounds have been reported in the last decades, and most of the reported lipopeptides produced by microorganisms were under aerobic conditions. The lipopeptide-producing strains under anaerobic conditions have attracted much attention from both the academic and industrial communities, due to the needs and the challenge of their applications in anaerobic environments, such as in oil reservoirs and in microbial enhanced oil recovery (MEOR). In this review, the fifty-eight reported bacterial strains, mostly isolated from oil reservoirs and dominated by the species Bacillus subtilis, producing lipopeptide biosurfactants, and the species Pseudomonas aeruginosa, producing glycolipid biosurfactants under anaerobic conditions were summarized. The metabolic pathway and the non-ribosomal peptide synthetases (NRPSs) of the strain Bacillus subtilis under anaerobic conditions were analyzed, which is expected to better understand the key mechanisms of the growth and production of lipopeptide biosurfactants of such kind of bacteria under anaerobic conditions, and to expand the industrial application of anaerobic biosurfactant-producing bacteria.
Journal Article
New evidence for a hydroxylation pathway for anaerobic alkane degradation supported by analyses of functional genes and signature metabolites in oil reservoirs
Microbial degradation of recalcitrant alkanes under anaerobic conditions results in the accumulation of heavy oil fraction in oil reservoirs. Hydroxylation of alkanes is an important activation mechanism under anaerobic conditions, but the diversity and distribution of the responsible microorganisms in the subsurface environment are still unclear. The lack of functional gene polymerase chain reaction (PCR) primers and commercially available intermediate degradation chemical compounds are the major obstacles for this research. In this investigation, PCR primers for the ahyA gene (encoding alkane hydroxylase) were designed, evaluated, and improved based on the nucleotide sequences available. Using microbial genomic DNA extracted from oil-contaminated soil and production water samples of oil reservoirs, ahyA gene nucleotide sequences were amplified and retrieved successfully from production water sample Z3-25 of Shengli oilfield. Additionally, the signature biomarker of 2-acetylalkanoic acid was detected in both Shengli and Jiangsu oilfields. These results demonstrate that anaerobic hydroxylation is an active mechanism used by microorganisms to degrade alkanes in oxygen-depleted oil reservoirs. This finding expands the current knowledge of biochemical reactions about alkane degradation in subsurface ecosystems. In addition, the PCR primers designed and tested in this study serve as an effective molecular tool for detecting the microorganisms responsible for anaerobic hydroxylation of alkanes in this and other ecosystems.
Journal Article
Dynamic Changes in Microbial Communities in Oil Reservoirs Under a Long-Term Bio-Chemical Flooding Operation
Huge amounts of water and chemicals have been injected into subsurface oil reservoirs in secondary and tertiary oil recovery processes. Although the effects of injected water and chemicals on microbial communities have been investigated, knowledge about their long-term dynamic changes in oil reservoirs remains limited. To address this gap, we used 16S rRNA sequencing from cDNA and chemical analysis to track the dynamic changes in microbial communities in oil reservoirs under a long-term flooding operation over three years and five months using bio-chemical flooding in the Daqing Oilfield, China. Researchers observed dynamic changes in microbial composition and diversity during the flooding process. Long-term bio-chemical drainage leads to alterations in dominant bacterial community structure, with a decrease in methanogenic archaeal abundance. Bacterial metabolic functions remained stable, but archaeal functions changed notably. Our results indicate that the microbial community and its functions in the oil reservoirs have experienced significant dynamic changes under the long-term flooding intervention of bio-chemical flooding, which opens up a new window for further understanding the impact of injected water and chemicals on microbial community in oil reservoirs and expands our knowledge about the role of microbial community changes in reservoirs under the flooding process.
Journal Article
Molecular phylogenetic diversity of the microbial community associated with a high-temperature petroleum reservoir at an offshore oilfield
The microbial community and its diversity in production water from a high-temperature, water-flooded petroleum reservoir of an offshore oilfield in China were characterized by 16S rRNA gene sequence analysis. The bacterial and archaeal 16S rRNA gene clone libraries were constructed from the community DNA and, using sequence analysis, 388 bacterial and 220 archaeal randomly selected clones were clustered with 60 and 28 phylotypes, respectively. The results showed that the 16S rRNA genes of bacterial clones belonged to the divisions Firmicutes, Thermotogae, Nitrospirae and Proteobacteria, whereas the archaeal library was dominated by methanogen-like rRNA genes (Methanothermobacter, Methanobacter, Methanobrevibacter and Methanococcus), with a lower percentage of clones belonging to Thermoprotei. Thermophilic microorganisms were found in the production water, as well as mesophilic microorganisms such as Pseudomonas and Acinetobacter-like clones. The thermophilic microorganisms may be common inhabitants of geothermally heated specialized subsurface environments, which have been isolated previously from a number of high-temperature petroleum reservoirs worldwide. The mesophilic microorganisms were probably introduced into the reservoir as it was being exploited. The results of this work provide further insight into the composition of microbial communities of high-temperature petroleum reservoirs at offshore oilfields.
Journal Article