Landform and lithospheric development contribute to the assembly of mountain floras in China.

Although it is well documented that mountains tend to exhibit high biodiversity, how geological processes affect the assemblage of montane floras is a matter of ongoing research. Here, we explore landform-specific differences among montane floras based on a dataset comprising 17,576 angiosperm species representing 140 Chinese mountain floras, which we define as the collection of all angiosperm species growing on a specific mountain. Our results show that igneous bedrock (granitic and karst-granitic landforms) is correlated with higher species richness and phylogenetic overdispersion, while the opposite is true for sedimentary bedrock (karst, Danxia, and desert landforms), which is correlated with phylogenetic clustering. Furthermore, we show that landform type was the primary determinant of the assembly of evolutionarily older species within floras, while climate was a greater determinant for younger species. Our study indicates that landform type not only affects montane species richness, but also contributes to the composition of montane floras. To explain the assembly and differentiation of mountain floras, we propose the 'floristic geo-lithology hypothesis', which highlights the role of bedrock and landform processes in montane floristic assembly and provides insights for future research on speciation, migration, and biodiversity in montane regions.

Integrated multilevel investigation of photosynthesis revealed the algal response distinction to differentially charged nanoplastics.

Nanoplastics (NPs), especially those with different charges, as one of emerging contaminants pose a threat to aquatic ecosystems. Although differentially charged NPs could induce distinct biological effects, mechanistic understanding of the critical physiological processes of aquatic organisms from an integrated multilevel perspective on aquatic organisms is still uncertain. Herein, multi-effects of differentially charged nanosized polystyrene (nPS) including neutral nPS, nPS-COOH, and nPS-NH2 on the photosynthesis-related physiological processes of algae were explored at the population, individual, subcellular, protein, and transcriptional levels. Results demonstrated that both nPS and nPS-COOH exhibited hormesis to algal photosynthesis but nPS-NH2 triggered severe inhibition. As for nPS-NH2, the integrity of algal subcellular structure, chlorophyll biosynthesis, and expression of photosynthesis-related proteins and genes were interfered. Intracellular NPs' content in nPS treatment was 25.64 % higher than in nPS-COOH treatment, and the content of chloroplasts in PS and nPS-COOH treatment were 3.09 % and 4.56 % higher than control, respectively. Furthermore, at the molecular levels, more photosynthesis-related proteins and genes were regulated under nPS-COOH exposure than those exposed to nPS. Light-harvesting complex II could be recognized as an underlying explanation for different effects between nPS and nPS-COOH. This study first provides a novel approach to assess the ecological risks of NPs at an integrated multilevel.

Microbial-driven mechanisms for the effects of heavy metals on soil organic carbon storage: A global analysis.

Heavy metal (HM) enrichment is closely related to soil organic carbon (SOC) pools in terrestrial ecosystems, which are deeply intertwined with soil microbial processes. However, the influence of HMs on SOC remains contentious in terms of magnitude and direction. A global analysis of 155 publications was conducted to integrate the synergistic responses of SOC and microorganisms to HM enrichment. A significant increase of 13.6 % in SOC content was observed in soils exposed to HMs. The response of SOC to HMs primarily depends on soil properties and habitat conditions, particularly the initial SOC content, mean annual precipitation (MAP), initial soil pH, and mean annual temperature (MAT). The presence of HMs resulted in significant decreases in the activities of key soil enzymes, including 31.9 % for soil dehydrogenase, 24.8 % for ß-glucosidase, 35.8 % for invertase, and 24.3 % for cellulose. HMs also exerted inhibitory effects on microbial biomass carbon (MBC) (26.6 %), microbial respiration (MR) (19.7 %), and the bacterial Shannon index (3.13 %) but elevated the microbial metabolic quotient (qCO2) (20.6 %). The HM enrichment-induced changes in SOC exhibited positive correlations with the response of MBC (r = 0.70, p < 0.01) and qCO2 (r = 0.50, p < 0.01), while it was negatively associated with ß-glucosidase activity (r = 0.72, p < 0.01) and MR (r = 0.39, p < 0.01). These findings suggest that the increase in SOC storage is mainly attributable to the inhibition of soil enzymes and microorganisms under HM enrichment. Overall, this meta-analysis highlights the habitat-dependent responses of SOC to HM enrichment and provides a comprehensive evaluation of soil carbon dynamics in an HM-rich environment.

Bacterial community regulation of soil organic matter molecular structure in heavy metal-rich mangrove sediments.

Heavy metals (HMs) profoundly impact soil carbon storage potential primarily through soil carbon structure. The association between HM content and soil carbon structure in mangrove sediments remains unclear, likely due to the involvement of microorganisms. In this study, surface sediments in the Futian National Mangrove Nature Reserve were sampled to investigate the chemical structure of soil organic carbon (SOC), the molecular composition of dissolved organic matter (DOM), and potential interactions with microorganisms. HMs, except for Ni, were positively correlated with soil carbon. HMs significantly reduced the alkyl C/O-alkyl C ratio, aromaticity index, and aromatic C values, but increased the labile carboxy/amide C and carbonyl C ratio in SOC. HMs also increased DOM stability, as reflected by the reduced abundance of labile DOM (lipids and proteins) and increased proportion of stable DOM (tannins and condensed aromatics). Bacteria increased the decomposition of labile DOM components (unsaturated hydrocarbons) and the accumulation of stable DOM components (lignins) under HM enrichment. In addition, the association between the bacterial groups and DOM molecules was more robust than that with fungal groups, indicating bacteria had a more significant impact on DOM molecular composition. These findings help in understanding the molecular mechanisms of soil carbon storage in HM-rich mangroves.

The characteristics of the intestinal bacterial community from Oreochromis mossambicus and its interaction with microbiota from artificial fishery habitats.

BACKGROUND: Artificial habitats can allow many fish to flock together and interact and have been widely used to restore and protect fishery resources. The piece of research intends to elucidate the relationship of microbial communities between tilapia (Oreochromis mossambicus) intestines and artificial fishery habitats (water and sediments). Hence, 16 S rDNA sequencing technology was used to study the bacterial communities from intestines, water, and sediments. RESULTS: The results showed that the tilapia intestines had the lowest richness of Operational Taxonomic Units (OTUs) and the lowest diversity of the bacterial community compared to water and sediments. The intestine, water, and sediment microbial communities shared many OTUs. Overall, 663 shared OTUs were identified from the tilapia intestines (76.20%), the surrounding water (71.14%), and sediment (56.86%) in artificial habitats. However, there were unique OTUs that were detected in different sample types. There were 81, 77 and 112 unique OTUs observed in tilapia intestines, the surrounding water and sediment, respectively. Proteobacteria, Cyanobacteria, Actinobacteria, Firmicutes, Fusobacteria, and Bacteroidetes were the most common and dominant bacterial phyla between the tilapia intestines and habitats. In the two groups, the microbial communities were similar in the taxonomic composition but different in the abundance of bacterial phyla. Interestingly, Firmicutes increased, while Fusobacteria decreased in artificial habitats. These findings indicated that the artificial habitats had fewer effects on the water environment and indicated that the mode of artificial habitats could have an effect on the enriched bacteria in the tilapia intestines. CONCLUSIONS: This study analysed the bacterial communities of artificial habitats from the intestines, water, and sediments, which can explain the relationship between the tilapia intestines and habitats and strengthen the value of ecological services provided by artificial habitats.

Insights into eco-corona formation and its role in the biological effects of nanomaterials from a molecular mechanisms perspective.

Broad application of nanotechnology inevitably results in the release of nanomaterials (NMs) into the aquatic environment, and the negative effects of NMs on aquatic organisms have received much attention. Notably, in the natural aquatic environment, ubiquitous ecological macromolecules (i.e., natural organic matter, extracellular polymeric substances, proteins, and metabolites) can easily adsorb onto the surfaces of NMs and form an "eco-corona". As most NMs have such an eco-corona modification, the properties of their eco-corona significantly determine the fate and ecotoxicity of NMs in the natural aquatic ecosystem. Therefore, it is of great importance to understand the role of the eco-corona to evaluate the environmental risks NMs pose. However, studies on the mechanism of eco-corona formation and its resulting nanotoxicity on aquatic organisms, especially at molecular levels, are rare. This review systemically summarizes the mechanisms of eco-corona formation by several typical ecological macromolecules. In addition, the similarities and differences in nanotoxicity between pristine and corona-coated NMs to aquatic organisms at different trophic levels were compared. Finally, recent findings about potential mechanisms on how NM coronas act on aquatic organisms are discussed, including cellular internalization, oxidative stress, and genotoxicity. The literature shows that 1) the formation of an eco-corona on NMs and its biological effect highly depend on both the composition and conformation of macromolecules; 2) both feeding behavior and body size of aquatic organisms at different trophic levels result in different responses to corona-coated NMs; 3) genotoxicity can be used as a promising biological endpoint for evaluating the role of eco-coronas in natural waters. This review provides informative insight for a better understanding of the role of eco-corona plays in the nanotoxicity of NMs to aquatic organisms which will aid the safe use of NMs.

Association of CYP24A1 gene polymorphism with colorectal cancer in the Jiamusi population.

BACKGROUND: The population in Jiamusi has been reported to have the highest prevalence of colorectal cancer (CRC) in China. The genetic causal-effect for this occurrence among the residents remains unclear. Given the long cold seasons with people wearing more clothes and reduced UV exposure, we aimed to study the association between the vitamin D metabolism-related gene CYP24A1 polymorphism and CRC susceptibility. METHOD: A case-control study was conducted that included 168 patients with CRC and 710 age-matched healthy individuals as the control group. Plausible susceptible variations were sought and clinical phenotypic-genotype association analysis was performed. RESULTS: Overall, two CYP24A1 polymorphisms, rs6013905 AX (P = 0.02, OR = 1.89, 95%CI: 1.09-3.29) and rs2762939 GX (P = 0.02, OR = 1.52, 95%CI: 1.08-2.13) were significantly associated with CRC in the Jiamusi population. In the female group, three CYP24A1 polymorphisms, rs6013905 AX (P = 0.04, OR = 2.59, 95%CI: 1.03-6.49), rs2762939 GX (P = 0.01, OR = 2.35, 95%CI: 1.25-4.42), and rs6068816 GG (P = 0.05, OR = 1.89, 95%CI: 0.99-3.59) carriers were significantly associated with CRC. In clinical phenotypic-genotype analysis, rs6013905 GG (P = 0.05, OR = 4.00, 95%CI: 0.92-17.48) and rs2762939 GX (P = 0.03, OR = 4.87, 95%CI: 1.00-23.69) carriers were significantly associated with poorly differentiated CRC, while CYP24A1 rs6068816 AX was significantly associated with the tumor type (P = 0.02, OR = 2.08, 95%CI: 1.10-3.96) and location (P = 0.04, OR = 2.24, 95%CI: 1.05-4.77). CONCLUSION: CYP24A1 gene polymorphism may be a genetic risk factor attributable to the highest prevalence of CRC in Jiamusi people. Individuals with CYP24A1 gene polymorphism may have an increased barrier for vitamin D absorption, thus contributing to the risk of CRC development.

Construction and Characterization of a Synergistic lncRNA-miRNA Network Reveals a Crucial and Prognostic Role of lncRNAs in Colon Cancer.

Non-coding RNAs such as long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) have been found to be indispensable factors in carcinogenesis and cancer development. Numerous studies have explored the regulatory functions of these molecules and identified the synergistic interactions among lncRNAs or miRNAs, while those between lncRNAs and miRNAs remain to be investigated. In this study, we constructed and characterized an lncRNA-miRNA synergistic network following a four-step approach by integrating the regulatory pairs and expression profiles. The synergistic interactions with more shared regulatory mRNAs were found to have higher interactional intensity. Through the analysis of nodes in the network, we found that lncRNAs played roles that are more central and had similar synergistic interactions with their neighbors when compared with miRNAs. In addition, known colon adenocarcinoma (COAD)-related RNAs were found to be enriched in this synergistic network, with higher degrees, betweenness, and closeness. Finally, we proposed a risk score model to predict the clinical outcome for COAD patients based on two prognostic hub lncRNAs, MEG3 and ZEB1-AS1. Moreover, the hierarchical networks of these two lncRNAs could contribute to the understanding of the biological mechanism of tumorigenesis. For each lncRNA-miRNA interaction in the hub-related subnetwork and two hierarchical networks, we performed RNAup method to evaluate their binding energy. Our results identified two important lncRNAs with prognostic roles in colon cancer and dissected their regulatory mechanism involving synergistic interaction with miRNAs.

Evaluation of three wheat (Triticum aestivum L.) cultivars as sensitive Cd biomarkers during the seedling stage.

Sensitive seedling crops have been developed to monitor Cadmium (Cd) contamination in agricultural soil. In the present study, 18 parameters involving growth conditions and physiological performances were assessed to evaluate Cd-responses of three wheat (Triticum aestivum L.) cultivars, Xihan1 (XH), Longzhong1 (LZ) and Dingfeng16 (DF). Principle component analysis illustrated that Factor 1, representing growth performance, soluble sugar content and catalase activity, responded to the Cd treatments in a dose dependent manner, while Factor 2 represented by chlorophyll content and germinating root growth was mainly dependent on cultivar differences. Higher inhibition rates were observed in growth performance than in physiological responses, with the highest inhibition rates of shoot biomasses (39.6%), root length (58.7%), root tip number (57.8%) and bifurcation number (83.2%), even under the lowest Cd treatment (2.5 mg·L-1). According to the Cd toxicity sensitivity evaluation, DF exerted highest tolerance to Cd stress in root growth while LZ was more sensitive to Cd stress, suggesting LZ as an ideal Cd contaminant biomarker. This study will provide novel insight into the cultivar-dependent response during using wheat seedlings as Cd biomarkers.

Novel and Neuroprotective Tetranortriterpenoids from Chinese Mangrove Xylocarpus granatum Koenig.

Eight new tetranortriterpenoids (1-8) were isolated from the twigs and leaves of the Chinese mangrove plant Xylocarpus granatum, together with four related known ones (9-12). The structures of new compounds were elucidated by detailed spectroscopic analysis. The absolute configuration of 9-epixylogranatin A (1) was determined by time-dependent density functional theory-electronic circular dichroism (TDDFT-ECD) calculations of the solution conformers. Xylogranatumin A (2) represents the first example of the 9, 10-seco limonoid with an unprecedented oxygen-bridged B ring (2,7-dioxabicyclo[2.2.1]-heptane). All the isolates were evaluated for the in vitro neuroprotective activity, both compounds 11 and 12 displayed moderate effects against H2O2-induced neurotoxicity in PC12 cells at the concentration of 10 µM, with an increase in cell viability of 12.0% and 11.6%, respectively.

Testing stem cell therapy in a rat model of inflammatory bowel disease: role of bone marrow stem cells and stem cell factor in mucosal regeneration.

BACKGROUND: The gastrointestinal (GI) mucosal cells turnover regularly under physiological conditions, which may be stimulated in various pathological situations including inflammation. Local epithelial stem cells appear to play a major role in such mucosal renewal or pathological regeneration. Less is clear about the involvement of multipotent stem cells from blood in GI repair. We attempted to explore a role of bone marrow mesenchymal stromal cells (BMMSCs) and soluble stem cell factor (SCF) in GI mucosa regeneration in a rat model of inflammatory bowel diseases (IBD). METHODS: BMMSCs labelled with the fluorescent dye PKH26 from donor rats were transfused into rats suffering indomethacin-induced GI injury. Experimental effects by BMMSCs transplant and SCF were determined by morphometry of intestinal mucosa, double labeling of PKH26 positive BMMSCs with endogenous proliferative and intestinal cell markers, and western blot and PCR analyses of the above molecular markers in the recipient rats relative to controls. RESULTS: PKH26 positive BMMSCs were found in the recipient mucosa, partially colocalizing with the proliferating cell nuclear antigen (PCNA), Lgr5, Musashi-1 and ephrin-B3. mRNA and protein levels of PCNA, Lgr5, Musashi-1 and ephrin-B3 were elevated in the intestine in BMMSCs-treated rats, most prominent in the BMMSCs-SCF co-treatment group. The mucosal layer and the crypt layer of the small intestine were thicker in BMMSCs-treated rats, more evident in the BMMSCs-SCF co-treatment group. CONCLUSION: BMMSCs and SCF participate in but may play a synergistic role in mucosal cell regeneration following experimentally induced intestinal injury. Bone marrow stem cell therapy and SCF administration may be of therapeutic value in IBD.

Heavy metal contamination in a vulnerable mangrove swamp in South China.

Concentrations of six heavy metals (Cu, Ni, Zn, Cd, Cr, and Pb) in sediments and fine roots, thick roots, branches, and leaves of six mangrove plant species collected from the Futian mangrove forest, South China were measured. The results show that both the sediments and plants in Futian mangrove ecosystem are moderately contaminated by heavy metals, with the main contaminants being Zn and Cu. All investigated metals showed very similar distribution patterns in the sediments, implying that they had the same anthropogenic source(s). High accumulations of the heavy metals were observed in the root tissues, especially the fine roots, and much lower concentrations in the other organs. This indicates that the roots strongly immobilize the heavy metals and (hence) that mangrove plants possess mechanisms that limit the upward transport of heavy metals and exclude them from sensitive tissues. The growth performance of propagules and 6-month-old seedlings of Bruguiera gymnorhiza in the presence of contaminating Cu and Cd was also examined. The results show that this plant is not sufficiently sensitive to heavy metals after its propagule stage for its regeneration and growth to be significantly affected by heavy metal contamination in the Futian mangrove ecosystem. However, older mangrove seedlings appeared to be more metal-tolerant than the younger seedlings due to their more efficient exclusion mechanism. Thus, the effects of metal contamination on young seedlings should be assessed when evaluating the risks posed by heavy metals in an ecosystem.

Absolute configurations of integracins A, B, and 15'-dehydroxy-integracin B.

Integracins A (1) and B (2), potent HIV-1 integrase inhibitors, and 15'-dehydroxy-integracin B (3) were isolated for the first time from Chinese mangrove plant Sonneratia hainanensis. Their absolute configurations were determined by the Mosher's method and specific rotation analysis of alcohols (6 and 7) obtained from integracin A in two steps and by chemical correlation. Integracin A (1) also exhibited significant cytotoxicity against the tumor cell lines HepG2 and NCI-H460 with both 100% inhibitions at 25 µg/ml.

Flooding greatly affects the diversity of arbuscular mycorrhizal fungi communities in the roots of wetland plants.

The communities of arbuscular mycorrhizal fungi (AMF) colonizing the roots of three mangrove species were characterized along a tidal gradient in a mangrove swamp. A fragment, designated SSU-ITS-LSU, including part of the small subunit (SSU), the entire internal transcribed spacer (ITS) and part of the large subunit (LSU) of rDNA from samples of AMF-colonized roots was amplified, cloned and sequenced using AMF-specific primers. Similar levels of AMF diversity to those observed in terrestrial ecosystems were detected in the roots, indicating that the communities of AMF in wetland ecosystems are not necessarily low in diversity. In total, 761 Glomeromycota sequences were obtained, which grouped, according to phylogenetic analysis using the SSU-ITS-LSU fragment, into 23 phylotypes, 22 of which belonged to Glomeraceae and one to Acaulosporaceae. The results indicate that flooding plays an important role in AMF diversity, and its effects appear to depend on the degree (duration) of flooding. Both host species and tide level affected community structure of AMF, indicating the presence of habitat and host species preferences.

Paracaseolide A, first α-alkylbutenolide dimer with an unusual tetraquinane oxa-cage bislactone skeleton from Chinese mangrove Sonneratia paracaseolaris.

A novel α-alkylbutenolide dimer, paracaseolide A (2), characterized by an unusual tetraquinane oxa-cage bislactone skeleton bearing two linear alkyl chains, was isolated from the mangrove plant Sonneratia paracaseolaris. The structure of 2 was elucidated by extensive spectroscopic analysis. A plausible retrosynthetic pathway for paracaseolide A (2) was proposed. Compound 2 exhibited significant inhibitory activity against dual specificity phosphatase CDC25B, a key enzyme for cell cycle progression, with an IC(50) value of 6.44 µM.

Piperidine alkaloids from Chinese mangrove Sonneratia hainanensis.

A new diphenacyl-piperidine alkaloid, sonneratine A (2), identified as a piperidine ring bearing two phenacyl substitutes at C-2 and C-6, and a known related derivative, (+/-)1-(2-piperidyl)-4-( P-methoxyphenyl)-butanone-2 (3), were isolated from the leaves and stems of the Hainan mangrove Sonneratia hainanensis. The structure of the new compound was determined by extensive analysis of its spectroscopic data and by comparison of its NMR data with those reported in the literature.

Diastereoisomeric macrocyclic polydisulfides from the mangrove Bruguiera gymnorrhiza.

The uncommon macrocyclic polydisulfides, trans-3,3'-dihydroxy-1,5,1',5'-tetrathiacyclodecane (1), cis-3,3'-dihydroxy-1,5,1',5'-tetrathiacyclodecane (2), along with five known related cyclic disulfides, gymnorrhizol (3), neogymnorrhizol (4), bruguiesulfurol (5), brugierol (6), and isobrugierol (7), were isolated from the mangrove Bruguiera gymnorrhiza collected from Guangdong Province, China. Structures of compounds 1 and 2 were determined by extensive analysis of their spectroscopic data, by comparison of their NMR spectroscopic data with those of the co-occurring known compounds, as well as by single-crystal X-ray diffraction analysis. A possible biogenetic origin was also proposed.