Effects of biodiversity,stand factors and functional identity on biomass and productivity during the restoration of subtropical forests in Central China

恢复梯度上华中亚热带森林生物多样性、林分因子及功能特性对生物量、生产力的影响 草地群落上进行的控制实验大都发现生物多样性对生态系统功能有显著促进作用。然而,在天然林中,多样性与林分因子、群落功能特性的相对作用大小仍存在争议。本文在森林恢复梯度上,研究这3类因素对生物量和生产力的相对影响。我们在湖北神农架设置了处于不同恢复阶段的24块(600 m²)亚热 带森林样地,计算了林分生物量和生产力。选择5个关键的植物功能性状,并计算了群落的功能多样性(功能丰富度、功能均匀度和功能离散度)和性状的加权平均值(CWM)。使用一般线性模型(GLMs)、变异分离等方法探究林分因子(密度、林龄、群落最大树高等)、功能特性、物种和功能多样性对生物量和生产力的相对重要性。研究结果表明,随着森林恢复,林分生物量和生产力显著增加,群落物种丰富度显著增加,而功能离散度显著降低。变异分离结果表明,多样性对生物量和生产力的单独效应不显著,但可能通过与林分因子和功能特性的协同效应来影响生物量和生产力。总体而言,我们发现林分因子对亚热带森林生物量和生产力的影响最大,功能特性显著影响生产力,但不影响生物量。这些结果说明,在森林经营中,调整林分结构和群落物种特性是提高森林碳储量和固碳潜力的有效途径。     

Nucleolin interacts with the rabbit hemorrhagic disease virus replicase RdRp,nonstructural proteins p16 and p23, playing a role in virus replication

Rabbit hemorrhagic disease virus (RHDV) is a member of the Caliciviridae family and cannot be propagated in vitro, which has impeded the progress of investigating its replication mechanism. Construction of an RHDV replicon system has recently provided a platform for exploring RHDV replication in host cells. Here, aided by this replicon system and using two-step affinity purification, we purified the RHDV replicase and identified its associated host factors. We identified rabbit nucleolin (NCL) as a physical link, which mediating the interaction between other RNA-dependent RNA polymerase (RdRp)-related host proteins and the viral replicase RdRp. We found that the overexpression or knockdown of NCL significantly increased or severely impaired RHDV replication in RK-13 cells, respectively. NCL was identified to directly interact with RHDV RdRp, p16, and p23. Furthermore, NCL knockdown severely impaired the binding of RdRp to RdRp-related host factors. Collectively, these results indicate that the host protein NCL is essential for RHDV replication and acts as a physical link between viral replicase and host proteins.     

Possible role of the CYC2c gene in the cornflower-like ray floret phenotype of Gaillardia cultivars

Journal of Plant Research - Gaillardia plants have been widely cultivated in China and have become an important component of garden landscaping. Different from the common ligulate ray floret, the...     

The Raf-like kinase Raf36 negatively regulates plant resistance against the oomycete pathogen Phytophthora parasitica by targeting MKK2

Oomycetes represent a unique group of plant pathogens that are phylogenetically distant from true fungi and cause significant crop losses and environmental damage. Understanding of the genetic basis of host plant susceptibility facilitates the development of novel disease resistance strategies. In this study, we report the identification of an Arabidopsis thaliana T-DNA mutant with enhanced resistance to Phytophthora parasitica with an insertion in the Raf-like mitogen-activated protein kinase kinase kinase gene Raf36. We generated additional raf36 mutants by CRISPR/Cas9 technology as well as Raf36 complementation and overexpression transformants, with consistent results of infection assays showing that Raf36 mediates Arabidopsis susceptibility to P. parasitica. Using a virus-induced gene silencing assay, we silenced Raf36 homologous genes in Nicotiana benthamiana and demonstrated by infection assays the conserved immune function of Raf36. Mutagenesis analyses indicated that the kinase activity of Raf36 is important for its immune function and interaction with MKK2, a MAPK kinase. By generating and analysing mkk2 mutants and MKK2 complementation and overexpression transformants, we found that MKK2 is a positive immune regulator in the response to P. parasitica infection. Furthermore, infection assay on mkk2 raf36 double mutant plants indicated that MKK2 is required for the raf36-conferred resistance to P. parasitica. Taken together, we identified a Raf-like kinase Raf36 as a novel plant susceptibility factor that functions upstream of MKK2 and directly targets it to negatively regulate plant resistance to P. parasitica.     

Straightforward method for calibration of mechanistic cation exchange chromatography models for industrial applications

Mechanistic modeling of chromatography processes is one of the most promising techniques for the digitalization of biopharmaceutical process development. Possible applications of chromatography models range from in silico process optimization in early phase development to in silico root cause investigation during manufacturing. Nonetheless, the cumbersome and complex model calibration still decelerates the implementation of mechanistic modeling in industry. Therefore, the industry demands model calibration strategies that ensure adequate model certainty in a limited amount of time. This study introduces a directed and straightforward approach for the calibration of pH-dependent, multicomponent steric mass action (SMA) isotherm models for industrial applications. In the case investigated, the method was applied to a monoclonal antibody (mAb) polishing step including four protein species. The developed strategy combined well-established theories of preparative chromatography (e.g. Yamamoto method) and allowed a systematic reduction of unknown model parameters to 7 from initially 32. Model uncertainty was reduced by designing two representative calibration experiments for the inverse estimation of remaining model parameters. Dedicated experiments with aggregate-enriched load material led to a significant reduction of model uncertainty for the estimates of this low-concentrated product-related impurity. The model was validated beyond the operating ranges of the final unit operation, enabling its application to late-stage downstream process development. With the proposed model calibration strategy, a systematic experimental design is provided, calibration effort is strongly reduced, and local minima are avoided.     

NCAM regulates the proliferation,apoptosis, autophagy,EMT, and migration of human melanoma cells via the Src/Akt/mTOR/cofilin signaling pathway

The neural cell adhesion molecule (NCAM) plays critical roles in multiple cellular processes in neural cells, mesenchymal stem cells, and various cancer cells. However, the effect and mechanism of NCAM in human melanoma cells are still unclear. In this study, we found that NCAM regulated the proliferation, apoptosis, autophagy, migration, and epithelial-to-mesenchymal transition of human melanoma cells by determining the biological behavior of NCAM knockdown A375 and M102 human melanoma cells. Further studies revealed that NCAM knockdown impaired the organization of actin cytoskeleton and reduced the phosphorylation of cofilin, an actin-cleaving protein. When cells were transfected with cofilin S3A (dephosphorylated cofilin), biological behavior similar to that of NCAM knockdown cells was observed. Research on the underlying molecular mechanism showed that NCAM knockdown suppressed activation of the Src/Akt/mTOR pathway. Specific inhibitors of Src and PI3K/Akt were employed to further verify the relationship between Src/Akt/mTOR signaling and cofilin, and the results showed that the phosphorylation level of cofilin decreased following inhibition of the Src/Akt/mTOR pathway. These results indicated that NCAM may regulate the proliferation, apoptosis, autophagy, migration, and epithelial-to-mesenchymal transition of human melanoma cells via the Src/Akt/mTOR/cofilin pathway-mediated dynamics of actin cytoskeleton.     

Tanshinone IIA inhibits the adipogenesis and inflammatory response in ox-LDL-challenged human monocyte-derived macrophages via regulating miR-130b/WNT5A

Atherosclerosis is a kind of chronic cardiovascular disease, characterized by oxidized low-density lipoprotein (ox-LDL) accumulation in macrophage. Tanshinone IIA (Tan), a lipophilic pharmacologically activate compound from Salvia miltiorrhiza Bunge, has been indicated to exert cardioprotective roles. Nevertheless, the biological role of Tan and regulatory mechanism in atherosclerosis are not fully established. In present study, atherosclerosis model was established in THP-1-derived macrophages by treatment of ox-LDL. The adipogenesis was measured by Nile red staining. The expressions of inflammatory factors, microRNA-130b (miR-130b) and WNT5A were measured by quantitative real-time polymerase chain reaction or Western blot. The target association between miR-130b and WNT5A was explored via luciferase activity and RNA immunoprecipitation assay. The results showed that exposure of Tan inhibited ox-LDL-induced adipogenesis and expressions of interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-alpha in THP-1-derived macrophages. miR-130b expression was decreased in THP-1-derived macrophages treated by ox-LDL and its overexpression attenuated adipogenesis as well as inflammatory response. miR-130b knockdown reversed the regulatory effect of Tan on adipogenesis and inflammatory response in THP-1-derived macrophages stimulated by ox-LDL. In addition, WNT5A acted as a functional target of miR-130b and inhibited by Tan and miR-130b. As a conclusion, Tan decreased the adipogenesis and inflammatory response by mediating miR-130b and WNT5A, providing a novel theoretical foundation for treatment of atherosclerosis.     

A new Illumina MiSeq high-throughput sequencing-based method for evaluating the composition of the Bacteroides community in the intestine using the rpsD gene sequence

Bacteroides is a bacterial genus that is known to closely interact with the host. The potential role of this genus is associated with its ecological status and distribution in the intestine. However, the current 16S V3–V4 region sequencing method can only detect the abundance of this genus, revealing a need for a novel sequencing method that can elucidate the composition of Bacteroides in the human gut microbiota. In this study, a core gene, rpsD, was selected as a template for the design of a Bacteroides-specific primer set. We used this primer set to develop a novel assay based on the Illumina MiSeq sequencing platform that enabled an accurate assessment of the Bacteroides compositions in complex samples. Known amounts of genomic DNA from 10 Bacteroides species were mixed with a complex sample and used to evaluate the performance and detection limit of our assay. The results were highly consistent with those of direct sequencing with a low Bacteroides DNA detection threshold (0.01 ng), supporting the reliability of our assay. In addition, the assay could detect all the known Bacteroides species within the faecal sample. In summary, we provide a sensitive and specific approach to determining the Bacteroides species in complex samples.