Seasonal shifts in the assembly dynamics of benthic macroinvertebrate and diatom communities in a subtropical river

Identifying seasonal shifts in community assembly for multiple biological groups is important to help enhance our understanding of their ecological dynamics. However, such knowledge on lotic assemblages is still limited. In this study, we used biological traits and functional diversity indices in association with null model analyses to detect seasonal shifts in the community assembly mechanisms of lotic macroinvertebrates and diatoms in an unregulated subtropical river in China. We found that functional composition and functional diversity (FRic, FEve, FDis, MNN, and SDNN) showed seasonal variation for macroinvertebrate and diatom assemblages. Null models suggested that environmental filtering, competitive exclusion, and neutral process were all important community assembly mechanisms for both biological groups. However, environmental filtering had a stronger effect on spring macroinvertebrate assemblages than autumn assemblages, but the effect on diatom assemblages was the same in both seasons. Moreover, macroinvertebrate and diatom assemblages were shaped by different environmental factors. Macroinvertebrates were filtered mainly by substrate types, velocity, and COD_Mn, while diatoms were mainly shaped by altitude, substrate types, and water quality. Therefore, our study showed (a) that different biological assemblages in a river system presented similarities and differences in community assembly mechanisms, (b) that multiple processes play important roles in maintaining benthic community structure, and (c) that these patterns and underlying mechanisms are seasonally variable. Thus, we highlight the importance of exploring the community assembly mechanisms of multiple biological groups, especially in different seasons, as this is crucial to improve the understanding of river community changes and their responses to environmental degradation.     

Ecological and morphological determinants of evolutionary diversification in Darwin's finches and their relatives

Darwin''s finches are a classic example of adaptive radiation, a process by which multiple ecologically distinct species rapidly evolve from a single ancestor. Such evolutionary diversification is typically explained by adaptation to new ecological opportunities. However, the ecological diversification of Darwin''s finches following their dispersal to Galápagos was not matched on the same archipelago by other lineages of colonizing land birds, which diversified very little in terms of both species number and morphology. To better understand the causes underlying the extraordinary variation in Darwin''s finches, we analyze the evolutionary dynamics of speciation and trait diversification in Thraupidae, including Coerebinae (Darwin''s finches and relatives) and, their closely related clade, Sporophilinae. For all traits, we observe an early pulse of speciation and morphological diversification followed by prolonged periods of slower steady‐state rates of change. The primary exception is the apparent recent increase in diversification rate in Darwin''s finches coupled with highly variable beak morphology, a potential key factor explaining this adaptive radiation. Our observations illustrate how the exploitation of ecological opportunity by contrasting means can produce clades with similarly high diversification rate yet strikingly different degrees of ecological and morphological differentiation.     

Genomic analysis of Asian honeybee populations in China reveals evolutionary relationships and adaptation to abiotic stress

The geographic and biological diversity of China has resulted in the differential adaptation of the eastern honeybee, Apis cerana, to these varied habitats. A. cerana were collected from 14 locations in China. Their genomes were sequenced, and nucleotide polymorphisms were identified at more than 9 million sites. Both STRUCTURE and principal component analysis placed the bees into seven groups. Phylogenomic analysis groups the honeybees into many of the same clusters with high bootstrap values (91%–100%). Populations from Tibet and South Yunnan are sister taxa and together represent the earliest diverging lineage included in this study. We propose that the evolutionary origin of A. cerana in China was in the southern region of Yunnan Province and expanded from there into the southeastern regions and into the northeastern mountain regions. The Cold‐Temperate West Sichuan Plateau and Tropical Diannan populations were compared to identify genes under adaptive selection in these two habitats. Pathway enrichment analysis showing genes under selection, including the Hippo signaling pathway, GABAergic pathway, and trehalose‐phosphate synthase, indicates that most genes under selection pressure are involved in the process of signal transduction and energy metabolism. qRT‐PCR analysis reveals that one gene under selection, the AcVIAAT gene, involved in the GABAergic pathway, is responding to cold temperature stress. Through homologous recombination, we show that the AcVIAAT gene is able to replace the CNAG_01904 gene in the fungus Cryptococcus neoformans and that it makes the fungus less sensitive to conditions of oxidative stress and variations in temperature. Our results contribute to our understanding of the evolutionary origin of A. cerana in China and the molecular basis of environmental adaptation.     

Effects of Different Potassium (K) Fertilizer Rates on Yield Formation and Lodging of Rice

As one of the most important nutrients for plants, potassium (K) has substantial effects on growth and development of crops. Present study was conducted in three different sites in South China in late season in 2019 with the objective to study the effects of different applied amounts of K fertilizer on yield formation and lodging of rice. Four K fertilizer treatments, K₀: 0 kg potassium oxide (K₂O) ha⁻¹ (control); K₁: 64.20 kg K₂O ha⁻¹ ; K₂: 128.55 kg K₂O ha⁻¹ and K₃ 153.90 kg K₂O ha⁻¹ were applied in the field experiment. The results showed that K₂ and K₃ treatments significantly increased panicle number per unit area, grain number per panicle, seed-setting rate and the grain yield of rice compared with K₀ treatment. Higher net photosynthetic rates were recorded in K₂ and K₃ treatments than K₀ treatment at tillering stage, heading stage and maturity stage. K fertilizer treatments also increased the chlorophyll content and dry matter accumulation by 6.16–23.52% and 21.32–64.59% compared with K₀ treatment, respectively. Moreover, the total N and K accumulation in the aboveground tissues of rice significantly increased under K₂ and K₃ treatments compared with K₀ treatment. Furthermore, compared with K₀ treatment, K fertilizer treatments significantly enhanced the breaking-resistant strength by 40.94–144.24% and reduced the lodging index of rice by 13.14–36.72%.     

Molecular mechanisms of An-Chuan Granule for the treatment of asthma based on a network pharmacology approach and experimental validation

An-Chuan Granule (ACG), a traditional Chinese medicine (TCM) formula, is an effective treatment for asthma but its pharmacological mechanism remains poorly understood. In the present study, network pharmacology was applied to explore the potential mechanism of ACG in the treatment of asthma. The tumor necrosis factor (TNF), Toll-like receptor (TLR), and Th17 cell differentiation-related, nucleotide-binding oligomerization domain (NOD)-like receptor, and NF-kappaB pathways were identified as the most significant signaling pathways involved in the therapeutic effect of ACG on asthma. A mouse asthma model was established using ovalbumin (OVA) to verify the effect of ACG and the underlying mechanism. The results showed that ACG treatment not only attenuated the clinical symptoms, but also reduced inflammatory cell infiltration, mucus secretion and MUC5AC production in lung tissue of asthmatic mice. In addition, ACG treatment notably decreased the inflammatory cell numbers in bronchoalveolar lavage fluid (BALF) and the levels of pro-inflammatory cytokines (including IL-6, IL-17, IL-23, TNF-alpha, IL-1beta and TGF-beta) in lung tissue of asthmatic mice. In addition, ACG treatment remarkably down-regulated the expression of TLR4, p-P65, NLRP3, Caspase-1 and adenosquamous carcinoma (ASC) in lung tissue. Further, ACG treatment decreased the expression of receptor-related orphan receptor (RORγt) in lung tissue but increased that of Forkhead box (Foxp3). In conclusion, the above results demonstrate that ACG alleviates the severity of asthma in a ´multi-compound and multi-target’ manner, which provides a basis for better understanding of the application of ACG in the treatment of asthma.     

mem-iLID,a fast and economic protein purification method

Protein purification is the vital basis to study the function, structure and interaction of proteins. Widely used methods are affinity chromatography-based purifications, which require different chromatography columns and harsh conditions, such as acidic pH and/or adding imidazole or high salt concentration, to elute and collect the purified proteins. Here we established an easy and fast purification method for soluble proteins under mild conditions, based on the light-induced protein dimerization system improved light-induced dimer (iLID), which regulates protein binding and release with light. We utilize the biological membrane, which can be easily separated by centrifugation, as the port to anchor the target proteins. In Xenopus laevis oocyte and Escherichia coli, the blue light-sensitive part of iLID, AsLOV2-SsrA, was targeted to the plasma membrane by different membrane anchors. The other part of iLID, SspB, was fused with the protein of interest (POI) and expressed in the cytosol. The SspB-POI can be captured to the membrane fraction through light-induced binding to AsLOV2-SsrA and then released purely to fresh buffer in the dark after simple centrifugation and washing. This method, named mem-iLID, is very flexible in scale and economic. We demonstrate the quickly obtained yield of two pure and fully functional enzymes: a DNA polymerase and a light-activated adenylyl cyclase. Furthermore, we also designed a new SspB mutant for better dissociation and less interference with the POI, which could potentially facilitate other optogenetic manipulations of protein–protein interaction.     

The correlation of microRNA-499 rs3746444 T>C locus with the susceptibility of gastric cancer: from a case–control study to a meta-analysis

The relationship between rs3746444 T>C single-nucleotide polymorphism (SNP) in microRNA (mir)-499 and risk of gastric cancer (GC) has been widely investigated. However, the association was still unconfirmed. Here, we first recruited 490 GC patients and 1476 controls, and conducted a case-control study. And we did not find any association between rs3746444 T>C SNP polymorphism and risk of GC. Subsequently, we conducted a meta-analysis to explore the association of mir-499 rs3746444 polymorphism with GC development. Two authors searched the PubMed and EMBASE databases up to October 15, 2019 independently. Finally, nine literatures involving 12 independent studies were included. In total, 3954 GC cases and 9745 controls were recruited for meta-analysis. The results suggested that allele model, homozygote model and recessive model could increase the risk of overall GC (P = 0.002, 0.009 and 0.013, respectively). When we excluded the studies violated HWE, this association was also found in allele model (P = 0.020) and dominant model (P= 0.044). In subgroup analyses, we identified that rs3746444 SNP in mir-499 increased the risk of GC in Asians and gastric cardiac adenocarcinoma (GCA) subgroups. No significant bias of selection was found (all P>0.1). Test of sensitivity analysis indicated that our findings were stable. Additionally, we found that the power value was 0.891 in the allele model, suggesting the reliability of our findings. In summary, our analysis confirmed the association between rs3746444 and the risk of GC, especially in Asians and in patients with GCA.     

HDAC6 inhibitor WT161 performs anti-tumor effect on osteosarcoma and synergistically interacts with 5-FU

Background: WT161, as a selective HDAC6 inhibitor, has been shown to play anti-tumor effects on several kinds of cancers. The aim of the present study is to explore the roles of WT161 in osteosarcoma and its underlying mechanisms.Methods: The anti-proliferative effect of WT161 on osteosarcoma cells was examined using MTT assay and colony formation assay. Cell apoptosis was analyzed using flow cytometer. The synergistic effect was evaluated by isobologram analysis using CompuSyn software. The osteosarcoma xenograft models were established to evaluate the anti-proliferative effect of WT161 in vivo.Results: WT161 suppressed the cell growth and induced apoptosis of osteosarcoma cells in a dose- and time-dependent manner. Mechanistically, we found that WT161 treatment obviously increased the protein level of PTEN and decreased the phosphorylation level of protein kinase-B (AKT). More importantly, WT161 showed synergistic inhibition with 5-FU on osteosarcoma cells in vitro and in vivo.Conclusions: These results indicate that WT161 inhibits the growth of osteosarcoma through PTEN and has a synergistic efficiency with 5-FU.     

Variation in rare earth element (REE), aluminium (Al) and silicon (Si) accumulation among populations of the hyperaccumulator Dicranopteris linearis in southern China

Plant and Soil - Dicranopteris linearis is a rare earth element (REE), aluminium (Al) and silicon (Si) hyperaccumulator plant which occurs in southern China. To date, there have been no studies on...