TFIIB-related factor 1 is a nucleolar protein that promotes RNA polymerase I-directed transcription and tumour cell growth.

Eukaryotic RNA polymerase I (Pol I) products play fundamental roles in ribosomal assembly, protein synthesis, metabolism and cell growth. Abnormal expression of both Pol I transcription-related factors and Pol I products causes a range of diseases, including ribosomopathies and cancers. However, the factors and mechanisms governing Pol I-dependent transcription remain to be elucidated. Here, we report that transcription factor IIB-related factor 1 (BRF1), a subunit of transcription factor IIIB required for RNA polymerase III (Pol III)-mediated transcription, is a nucleolar protein and modulates Pol I-mediated transcription. We showed that BRF1 can be localized to the nucleolus in several human cell types. BRF1 expression correlates positively with Pol I product levels and tumour cell growth in vitro and in vivo. Pol III transcription inhibition assays confirmed that BRF1 modulates Pol I-directed transcription in an independent manner rather than through a Pol III product-to-45S pre-rRNA feedback mode. Mechanistically, BRF1 binds to the Pol I transcription machinery components and can be recruited to the rDNA promoter along with them. Additionally, alteration of BRF1 expression affects the recruitment of Pol I transcription machinery components to the rDNA promoter and the expression of TBP and TAF1A. These findings indicate that BRF1 modulates Pol I-directed transcription by controlling the expression of selective factor 1 subunits. In summary, we identified a novel role of BRF1 in Pol I-directed transcription, suggesting that BRF1 can independently regulate both Pol I- and Pol III-mediated transcription and act as a key coordinator of Pol I and Pol III.

Transcription factor AP-2α activates RNA polymerase III-directed transcription and tumor cell proliferation by controlling expression of c-MYC and p53.

Deregulation of transcription factor AP2 alpha (TFAP2A) and RNA polymerase III (Pol III) products is associated with tumorigenesis. However, the mechanism underlying this event is not fully understood and the connection between TFAP2A and Pol III-directed transcription has not been investigated. Here, we report that TFAP2A functions as a positive factor in the regulation of Pol III-directed transcription and cell proliferation. We found TFAP2A is also required for the activation of Pol III transcription induced by the silencing of filamin A, a well-known cytoskeletal protein and an inhibitor in Pol III-dependent transcription identified previously. Using a chromatin immunoprecipitation technique, we showed TFAP2A positively modulates the assembly of Pol III transcription machinery factors at Pol III-transcribed gene loci. We found TFAP2A can activate the expression of Pol III transcription-related factors, including BRF1, GTF3C2, and c-MYC. Furthermore, we demonstrate TFAP2A enhances expression of MDM2, a negative regulator of tumor suppressor p53, and also inhibits p53 expression. Finally, we found MDM2 overexpression can rescue the inhibition of Pol III-directed transcription and cell proliferation caused by TFAP2A silencing. In summary, we identified that TFAP2A can activate Pol III-directed transcription by controlling multiple pathways, including general transcription factors, c-MYC and MDM2/p53. The findings from this study provide novel insights into the regulatory mechanisms of Pol III-dependent transcription and cancer cell proliferation.

Species packing and the latitudinal gradient in beta-diversity.

The decline in species richness at higher latitudes is among the most fundamental patterns in ecology. Whether changes in species composition across space (beta-diversity) contribute to this gradient of overall species richness (gamma-diversity) remains hotly debated. Previous studies that failed to resolve the issue suffered from a well-known tendency for small samples in areas with high gamma-diversity to have inflated measures of beta-diversity. Here, we provide a novel analytical test, using beta-diversity metrics that correct the gamma-diversity and sampling biases, to compare beta-diversity and species packing across a latitudinal gradient in tree species richness of 21 large forest plots along a large environmental gradient in East Asia. We demonstrate that after accounting for topography and correcting the gamma-diversity bias, tropical forests still have higher beta-diversity than temperate analogues. This suggests that beta-diversity contributes to the latitudinal species richness gradient as a component of gamma-diversity. Moreover, both niche specialization and niche marginality (a measure of niche spacing along an environmental gradient) also increase towards the equator, after controlling for the effect of topographical heterogeneity. This supports the joint importance of tighter species packing and larger niche space in tropical forests while also demonstrating the importance of local processes in controlling beta-diversity.

Flocculation Efficiency and Mechanism of Carbamazepine by Microbial Flocculant Extracted from Klebsiella pneumoniae J1.

The microbial flocculant (MFX) extracted from Klebsiella pneumoniae J1 was used to remove carbamazepine in prepared wastewater and domestic sewage. The influence factors and flocculation mechanism were studied. The optimal carbamazepine removal conditions for MFX were pH of 7-8, 7 mL of flocculant, 0.1 mL of coagulant, and 35°C, and the removal rate reached 81.75%. MFX was efficient in the removal of carbamazepine in both domestic sewage (75.03%) and secondary sedimentation tank effluent (69.76%). The pseudo-first-order kinetic equation fitted the adsorption process better than the pseudo-second-order kinetic equation, which suggested that the adsorption was not pure chemical adsorption. The analysis of floc size suggested that the repulsive force between carbamazepine and MFX was weakened under alkalescent conditions, which can help the growth and coherence of flocs and increase the carbamazepine removal efficiency. Enough dosage of MFX can generate larger flocs, but excessive dosage of MFX will decrease the carbamazepine removal rate because of increase in electrostatic repulsion. The analysis of 3D-EEM and FTIR suggested that hydroxyl, amino, and carboxyl in MFX played an important role in the removal of carbamazepine. As an eco-friendly and highly efficient microbial flocculant, MFX has potential for practical applications in carbamazepine removal.

Ultrasound measurement of laryngeal structures in the parasagittal plane for the prediction of difficult laryngoscopies in Chinese adults.

BACKGROUND: Abnormal laryngeal structures are likely to be associated with a difficult laryngoscopy procedure. Currently, laryngeal structures can be measured by ultrasonography, however, little research has been performed on the potential role of ultrasound on the evaluation of a difficult laryngoscopy. The present study investigated the value of laryngeal structure measurements for predicting a difficult laryngoscopy. OBJECTIVE: The main objective of this study was to explore the value of laryngeal structure measurements for predicting a difficult laryngoscopy. METHODS: Two hundred and eleven adult patients (over 18 years old) were recruited to undergo elective surgery under general anesthesia via endotracheal intubation. Ultrasound was utilized to measure the distance between the skin and thyroid cartilage (DST), the distance between the thyroid cartilage and epiglottis (DTE), and the distance between the skin and epiglottis (DSE) in the parasagittal plane. These metrics were then investigated as predictors for classifying a laryngoscopy as difficult vs easy, as defined by the Cormack and Lehane grading scale. RESULTS: Multivariate logistic regression showed that the DSE, but not DST or DTE, was significantly related to difficult laryngoscopies. Specifically, a DSE ≥ 2.36 cm predicted difficult laryngoscopies with a sensitivity and specificity of 0.818 (95% CI: 0.766-0.870) and 0.856 (95% CI: 0.809-0.904). Furthermore, when combining the best model constructed of other indicators (i.e. sex, body mass index, modified Mallampati test) to predict the difficult laryngoscopy, the AUC reached 93.28%. CONCLUSION: DSE is an independent predictor of a difficult laryngoscopy; a DSE cutoff value of 2.36 cm is a better predictor of a difficult laryngoscope than other ultrasound or physiological measurements for predicting a difficult laryngoscope. Nevertheless, it's more valuable to apply the best model of this study, composed of various physiological measurements, for this prediction purpose.

NbGIS regulates glandular trichome initiation through GA signaling in tobacco.

KEY MESSAGE: A novel gene NbGIS positively regulates glandular trichome initiation through GA Signaling in tobacco. NbMYB123-like regulates glandular trichome initiation by acting downstream of NbGIS in tobacco. Glandular trichome is a specialized multicellular structure which has capability to synthesize and secrete secondary metabolites and protects plants from biotic and abiotic stresses. Our previous results revealed that a C2H2 zinc-finger transcription factor GIS and its sub-family genes act upstream of GL3/EGL3-GL1-TTG1 transcriptional activator complex to regulate trichome initiation in Arabidopsis. In this present study, we found that NbGIS could positively regulate glandular trichome development in Nicotiana benthamiana (tobacco). Our result demonstrated that 35S:NbGIS lines exhibited much higher densities of trichome on leaves, main stems, lateral branches and sepals than WT plants, while NbGIS:RNAi lines had the opposite phenotypes. Furthermore, our results also showed that NbGIS was required in response to GA signal to control glandular trichome initiation in Nicotiana benthamiana. In addition, our results also showed that NbGIS significantly influenced GA accumulation and expressions of marker genes of the GA biosynthesis, might result in the changes of growth and maturation in tobacco. Lastly, our results also showed that NbMYB123-like regulated glandular trichome initiation in tobacco by acting downstream of NbGIS. These findings provide new insights to discover the molecular mechanism by which C2H2 transcriptional factors regulates glandular trichome initiation through GA signaling pathway in tobacco.

Comparison of Microbial Diversity of Two Typical Volcanic Soils in Wudalianchi, China.

Volcanic lava is an excellent model of primary succession, in which basalt-associated microorganisms drive the cycling of different elements such as nitrogen, carbon, and other nutrients. Microbial communities in volcanic soils are of particular interest for study on the emergence and evolution of life within special and extreme conditions. The initial processes of colonization and subsequent rock weathering by microbial communities are still poorly understood. We analyzed the soil bacterial and fungal communities and diversities associated with lava (LBL) and kipuka (BK) sites in Wudalianchi using 16S and ITS rRNA Illumina Miseq sequencing techniques. The results showed that soil physical and chemical properties (pH, MC, TOC, TN, TP, AP, DOC, and DON) significantly differed between LBL and BK. The Shannon, Ace, and Pd indexes of fungi in the two sites showed a significant difference (p < 0.05). The dominant bacterial phyla forming communities at LBL and BK sites were Acidobacteria, Proteobacteria, Actinobacteria, and Basidiomycota, and their differences were driven by Gemmatimonadetes and Verrucomicrobia. The dominant fungal phyla of LBL and BK sites were Ascomycota, Zygomycota, and Rozellomcota, which differed significantly between the two sites. The microbial communities showed extremely significant differences (p < 0.05), with MC, pH, and nitrogen being the main influencing factors according to RDA/CCA and correlation analysis. Microbial functional prediction analysis across the two sites showed that the relative abundance of advantageous functional groups was significantly different (p < 0.05). The combined results drive us to conclude that the volcanic soil differences in the deposits appear to be the main factor shaping the microbial communities in Wudalianchi (WDLC) volcanic ecosystems.

Fabrication and properties of TiO2 nanofilms on different substrates by a novel and universal method of Ti-ion implantation and subsequent annealing.

We report a new, novel and universal method to fabricate high-quality titanium dioxide (TiO2) nanofilms on different substrates by a solid phase growth process of ion implantation and subsequent annealing in oxygen atmosphere. Ti ions were implanted into fused silica, soda lime glass, Z-cut quartz, or (0001) α-sapphire by a metal vapor vacuum arc (MEVVA) ion source implanter to fluences of 0.75, 1.5 and 3 × 10(17) ions cm(-2) with a nominal accelerating voltage of 20 kV. To understand the influence of the annealing temperature, time, and substrate on the formation and phase transformation of the TiO2 nanofilms, the Ti-ion-implanted substrates were annealed in oxygen atmosphere from 500 to 1000 °C for 1-6 h. The formation of TiO2 nanofilms resulted from the slow out-diffusion of implanted Ti ions from the substrates which were then oxidized at the surfaces. The thickness and phase of the nanofilms can be tailored by controlling the implantation and annealing parameters. Since the TiO2 nanofilms are formed under high temperature and low growth rate, they show good crystallinity and antibacterial properties, with good film adhesion and stability, suggesting that the TiO2 nanofilms formed by this method have great potential in applications such as antibacterial and self-cleaning transparent glass.

Dexmedetomidine attenuates neuroinflammation and microglia activation in LPS-stimulated BV2 microglia cells through targeting circ-Shank3/miR-140-3p/TLR4 axis.

It has been shown that dexmedetomidine (Dex) could attenuate postoperative cognitive dysfunction (POCD) via targeting circular RNAs (circRNAs). Circ-Shank3 has been found to be involved in the neuroprotective effects of Dex against POCD. However, the role of circ-Shank3 in POCD remains largely unknown. Reverse transcription quantitative PCR (RT-qPCR) was performed to detect circ-Shank3 and miR-140-3p levels in lipopolysaccharide (LPS)-treated microglia BV-2 cells in the absence or presence of Dex. The relationship among circ-Shank3, miR-140-3p and TLR4 was confirmed by dual-luciferase reporter assay. Additionally, Western blot and immunofluorescence (IF) assays were conducted to evaluate TLR4, p65 and Iba-1 or CD11b levels in cells. In this study, we found that Dex notably decreased circ-Shank3 and TLR4 levels and elevated miR-140-3p level in LPS-treated BV2 cells. Mechanistically, circ-Shank3 harbor miR-140-3p, functioning as a miRNA sponge, and then miR-140-3p targeted the 3'-UTR of TLR4. Additionally, Dex treatment significantly reduced TLR4 level and phosphorylation of p65, and decreased the expressions of microglia markers Iba-1 and CD11b in LPS-treated BV2 cells. As expected, silenced circ-Shank3 further reduced TLR4, p65 and Iba-1 and CD11b levels in LPS-treated BV2 cells in the presence of Dex, whereas these phenomena were reversed by miR-140-3p inhibitor. Collectively, our results found that Dex could attenuate the neuroinflammation and microglia activation in BV2 cells exposed to LPS via targeting circ-Shank3/miR-140-3p/TLR4 axis. Our results might shed a new light on the mechanism of Dex for the treatment of POCD.

High Ammonium Addition Changes the Diversity and Structure of Bacterial Communities in Temperate Wetland Soils of Northeastern China.

The soil microbiome is an important component of wetland ecosystems and plays a pivotal role in nutrient cycling and climate regulation. Nitrogen (N) addition influences the soil's microbial diversity, composition, and function by affecting the soil's nutrient status. The change in soil bacterial diversity and composition in temperate wetland ecosystems in response to high ammonium nitrogen additions remains unclear. In this study, we used high-throughput sequencing technology to study the changes of soil bacterial diversity and community structure with increasing ammonium concentrations [CK (control, 0 kg ha-1 a-1), LN (low nitrogen addition, 40 kg ha-1 a-1), and HN (high nitrogen addition, 80 kg ha-1 a-1)] at a field experimental site in the Sanjiang Plain wetland, China. Our results showed that except for soil organic carbon (SOC), other soil physicochemical parameters, i.e., soil moisture content (SMC), dissolved organic nitrogen (DON), total nitrogen (TN), pH, ammonium nitrogen (NH4+), and dissolved organic carbon (DOC), changed significantly among three ammonium nitrogen addition concentrations (p < 0.05). Compared to CK, LN did not change soil bacterial α-diversity (p > 0.05), and HN only decreased the Shannon (p < 0.05) and did not change the Chao (p > 0.05) indices of soil bacterial community. Ammonium nitrogen addition did not significantly affect the soil's bacterial community structure based on non-metric multidimensional scaling (NMDS) and PERMANOVA (ADONIS) analyses. Acidobacteriota (24.96-31.11%), Proteobacteria (16.82-26.78%), Chloroflexi (10.34-18.09%), Verrucomicrobiota (5.23-11.56%), and Actinobacteriota (5.63-8.75%) were the most abundant bacterial phyla in the soils. Nitrogen addition changed the complexity and stability of the bacterial network. SMC, NO3-, and pH were the main drivers of the bacterial community structure. These findings indicate that enhanced atmospheric nitrogen addition may have an impact on bacterial communities in soil, and this study will allow us to better understand the response of the soil microbiome in wetland ecosystems in the framework of increasing nitrogen deposition.

Food preference strategy of four sympatric rodents in a temperate forest in northeast China.

Rodents are well known as both seed predators and dispersers of various plant species in forest ecosystems, and they play an important role in the regeneration of vegetation. Thus, the research on seed selection and vegetation regeneration by sympatric rodents is an interesting topic. To understand the characteristics of preferences of rodents for different seeds, a semi-natural enclosure experiment was performed with four rodent species (Apodemuspeninsulae, Apodemusagrarius, Tscherskiatriton, and Clethrionomysrufocanus) and the seeds of seven plant species (Pinuskoraiensis, Corylusmandshurica, Quercusmongolica, Juglansmandshurica, Armeniacasibirica, Prunussalicina, and Cerasustomentosa) to investigate the differentiation in niches and patterns of resource utilization of sympatric rodents. The results showed that all the rodents had consumed many seeds of Pi.koraiensis, Co.mandshurica, and Q.mongolica but differed significantly in how they selected the different seeds. The rate of utilization (Ri) of Pi.koraiensis, Co.mandshurica, and Q.mongolica exhibited the highest values. The Ei values indicated that the rodents tested exhibited differences in their priorities used to select the seeds from different plant species. All four species of rodents exhibited obvious preferences for certain seeds. Korean field mice preferentially consumed the seeds of Q.mongolica, Co.mandshurica, and Pi.koraiensis. Striped field mice favor the seeds of Co.mandshurica, Q.mongolica, P.koraiensis, and Nanking cherry. Greater long-tailed hamsters prefer to consume the seeds of Pi.koraiensis, Co.mandshurica, Q.mongolica, Pr.salicina, and Ce.tomentosa. Clethrionomysrufocanus likes to eat the seeds of Pi.koraiensis, Q.mongolica, Co.mandshurica, and Ce.tomentosa. The results supported our hypothesis that sympatric rodents overlap in food selection. However, each rodent species has a marked preference for food selection, and different rodent species differ in their food preferences. This reflects the role of distinct food niche differentiation in their coexistence.

Effects of habitat differences on the scatter-hoarding behaviour of rodents (Mammalia, Rodentia) in temperate forests.

To discover the differences in hoarding strategies of rodents for different seeds in different habitats, we labelled and released three different types of seeds, including Pinuskoraiensis, Corylusmandshurica, and Quercusmongolica, in temperate forests of northeastern China and investigated the fate of seeds in four different habitats that included a broad-leaved forest, mixed-forest edge, mixed forest, and artificial larch forest. Our research showed that the hoarding strategy of rodents was found to vary substantially in different habitats. The survival curves of seeds from different habitats showed the same trend, but the rates of consumption in different habitats varied. More than 50% of the seeds in the four habitats were consumed by the tenth day. It took 20 days to consume more than 70% of the seeds. The rate of consumption of P.koraiensis seeds reached 96.70%; 99.09% of the C.mandshurica seeds were consumed, and 93.07% of the Q.mongolica seeds were consumed. The seeds were consumed most quickly in the artificial larch forest. In general, most of the early seeds were quickly devoured. After day 20, the consumption gradually decreased. Rodents found the seeds in the artificial larch forest in a shorter average time than those in the other types of forests. The average earliest discovery time was 1.4 ± 0.9 d (1-3 d). The average earliest discovery time in all the other three habitats exceeded 7 d. The median removal times (MRT) was distributed around the seeds at 14.24 ± 10.53 d (1-60 d). There were significant differences in the MRT among different habitats. It was shortest in the artificial larch forest at 7.67 ± 6.80 d (1-28 d). In contrast, the MRT in the broad-leaved forest was the longest at 17.52 ± 12.91 d (4-60 d). There were significant differences in the MRT between the artificial larch forest and the other habitats. There was less predation of the three types of seeds at the mixed-forest edge, and the most seeds were dispersed. The rates of predation of the P.koraiensis, C.mandshurica, and Q.mongolica seeds were 28.33%, 15.83%, and 44.0%, and 59.17%, 84.17%, and 48.0% of the seeds were dispersed, respectively. The average dispersal distances of all the seeds were less than 6 m, and the longest distance recorded was 18.66 m. The dispersal distances and burial depths differed significantly among the four types of habitats. The distance of seed dispersal was primarily distributed in 1-6 m.

Dexmedetomidine attenuates the neuroinflammation and cognitive dysfunction in aged mice by targeting the SNHG14/miR­340/NF­κB axis.

Neuroinflammation plays a key role in the pathogenesis of postoperative cognitive dysfunction (POCD). Results of our previous study demonstrated that dexmedetomidine (Dex) attenuates neuroinflammation in BV2 cells treated with lipopolysaccharide (LPS) by targeting the microRNA (miR)-340/NF-κB axis. However, the molecular mechanisms by which Dex improves POCD remain unclear. In the present study, the association between long non-coding (lnc)RNA small nucleolar RNA host gene 14 (SNHG14) and miR-340 in BV2 microglial cells was determined using a dual-luciferase reporter assay. In addition, SNHG14, miR-340 and NF-κB expression levels were measured in LPS-treated BV-2 cells and hippocampal tissues of mice with POCD, and an enzyme-linked immunosorbent assay was used to determine the levels of proinflammatory mediators. Results of the present study demonstrated that SNHG14 exhibited potential as a target of miR-340. In addition, SNHG14 knockdown increased the levels of miR-340 and reduced the levels of NF-κB in LPS-treated BV2 cells. In addition, Dex treatment significantly reduced the levels of SNHG14 and NF-κB, and elevated the levels of miR-340 in the hippocampus of aged mice with POCD. Moreover, Dex treatment notably decreased the expression levels of TNF-α, IL-1ß, IL-2, IL-6, IL-8 and IL-12 in the hippocampus of aged mice with POCD by upregulating miR-340. The spatial memory impairments in aged mice with POCD were also notably increased following Dex treatment via upregulation of miR-340. Collectively, results of the present study demonstrated that Dex may protect microglia from LPS-induced neuroinflammation in vitro and attenuate hippocampal neuroinflammation in aged mice with POCD in vivo via the SNHG14/miR-340/NF-κB axis. The present study may provide further insights into the mechanisms underlying Dex in the treatment of POCD.

Effects of bacteria on early-stage litter decomposition in Wudalianchi volcanic forest.

To understand the role of microorganisms in litter decomposition and nutrient cycling in volcanic forest ecosystem, we conducted in-situ litterbag decomposition experiment and used Illumina MiSeq high-throughput sequencing to analyze the response of bacterial community structure and diversity during the decomposition of litters from Larix gmelinii, Betula platyphylla and Populus davidiana, the dominant tree species in volcanic lava plateau of Wudalianchi. The results showed that mass remaining percentage of litters of three species after 18-month decomposition was 63.9%-68.1%. Litter of B. platyphylla decomposed the fastest, with significant difference in N, C:N, and N:P before and after decomposition. The richness of bacterial species and diversity index differed significantly among the three litters. Proteobacteria, Actinomycetes, and Bacteroidetes were the dominant bacterial groups at the phylum level, while Rhizobium, Sphingomonas, and Pseudomonas were the dominant groups at the genus level, with significant difference among the three litters. After 18 months, the dominant bacterial groups in litter tended to be consistent with those in volcanic lava platform soil. In the volcanic forest ecosystem, bacterial diversity and community structure were mainly affected by P, C:N, and N:P in the litter.

Comparative transcriptomics reveals the immune dynamics during the molting cycle of swimming crab Portunus trituberculatus.

Molting is one of the most important biological processes of crustacean species, and a number of molecular mechanisms facilitate this complex procedure. However, the understanding of the immune mechanisms underlying crustacean molting cycle remains very limited. This study performed transcriptome sequencing in hemolymph and hepatopancreas of the swimming crab (Portunus trituberculatus) during the four molting stages: post-molt (AB), inter-molt (C), pre-molt (D), and ecdysis (E). The results showed that there were 78,572 unigenes that were obtained in the hemolymph and hepatopancreas of P. trituberculatus. Further analysis showed that 98 DEGs were involved in immunity response of hemolymph and hepatopancreas, and most of the DEGs participated in the process of signal transduction, pattern recognition proteins/receptors, and antioxidative enzymes system. Specifically, the key genes and pathway involved in signal transduction including the GPCR126, beta-integrin, integrin, three genes in mitogen-activated protein kinase (MAPK) signaling cascade (MAPKKK10, MAPKK4, and p38 MAPK), and four genes in Toll pathway (Toll-like receptor, cactus, pelle-like kinase, and NFIL3). For the pattern recognition proteins/receptors, the lowest expression level of 11 genes was found in the E stage, including C-type lectin receptor, C-type lectin domain family 6 member A and SRB3/C in the hemolymph, and hepatopancreatic lectin 4, C-type lectin, SRB, Down syndrome cell adhesion molecule homolog, Down syndrome cell adhesion molecule isoform, and A2M. Moreover, the expression level of copper/zinc superoxide dismutase isoform 4, glutathione peroxidase, glutathione S-transferase, peroxiredoxin, peroxiredoxin 6, and dual oxidase 2 in stage C or stage D significantly higher than that of stage E or stage AB. These results fill in the gap of the continuous transcriptional changes that are evident during the molting cycle of crab and further provided valuable information for elucidating the molecular mechanisms of immune regulation during the molting cycle of crab.

Soil Acidobacterial community composition changes sensitively with wetland degradation in northeastern of China.

Acidobacteria are a major component of the soil bacteria and are conducted for many soil functions, and the soil Acidobacterial structure and diversity are affected by climate changes and human activities. However, soil Acidobacterial structure and diversity in wetland ecosystems are still limited recognized. The current study aimed to study the Acidobacterial community and diversity in relation to soil environmental factors along a typical degradation series from primitive wetland to forest in a representative fresh wetland in northeastern China. In this research, we assessed the soil Acidobacterial community composition, using Illumina MiSeq sequencing along a typical degradation series from primitive wetland to forest in a representative fresh wetland in northeastern China. The soil physico chemical properties changed significantly among the eight degrade stages (p < 0.05). The α diversity index (Shannon and Chao1 index) of soil Acidobacteria changed significantly between different degradation stages (p < 0.05). Principal Coordinates Analysis (PCoA) revealed that the soil acidobacteiral communities obviously separated into wetland group and forest group. The most abundant subgroups of Acidobacteria accounted for 31% (Gp1), 5% (Gp2), 12% (Gp3), 2% (Gp4), 5% (Gp6), and 2% (Gp7) in soils within eight successional series. The compositions of soil Acidobacteria in wetland stages were significantly affected by soil moisture content, soil total nitrogen and available nitrogen contents, while those in forest stages were significantly driven by soil pH, soil organic carbon, total nitrogen, available phosphorus and soil moisture content. Our results indicated that the soil Acidobacterial community was mainly structured by soil physico chemical parameters, and wetland degradation towards forests will greatly influence the soil Acidobacterial structure and thus the wetland functions.

[Effects of water levels in heterogeneous habitats on sexual reproductive allocation of Deyeuxia angustifolia.] / å¼‚è´¨ç”Ÿå¢ƒæ°´ä½å·®å¼‚å¯¹å°å¶ç« æœ‰æ€§ç¹æ®–åˆ†é çš„å½±å“.

Taking Deyeuxia angustifolia as the research object, a representative plant of wetland in Sanjiang Plain, we analyzed the variations of individual size and biomass among the habitats of swamp wetlands, swampy meadows, typical meadows and miscellaneous grass meadows, and the relationship between reproductive components and plant biomass. We explored the effects of water level on individual biomass and reproductive allocation of D. angustifolia in different types of wetlands. The results showed that plant biomass, height and the characteristics of sexual reproduction significantly decreased with the increases of water level. The reproductive thresholds of D. angustifolia in miscellaneous grass meadow, typical meadow, swampy meadow, and swamp wetland were 0.245, 0.149, 0.148 and 0.157 g, respectively. There was a significantly negative correlation between plant size and reproductive allocation in three habitats except swampy meadow. Compared with individual size, soil water content had a stronger effect on reproductive allocation of D. angustifolia. The different investment between individual size and reproductive allocation in different habitats was the basic condition that contributes to the good ecological adaptability of D. angustifolia.

Controllable growth of conical and cylindrical TiO2-carbon core-shell nanofiber arrays and morphologically dependent electrochemical properties.

Quasi-aligned cylindrical and conical core-shell nanofibers consisting of carbon shells and TiO(2) nanowire cores are produced in situ on Ti foils without using a foreign metallic catalyst and template. A cylindrical nanofiber has a TiO(2) nanowire core 30-50 nm in diameter and a 5-10 nm-thick cylindrical carbon shell, while in the conical nanostructure the TiO(2) nanowire core has a diameter of 20-40 nm and the thickness of the carbon shell varies from about 200 nm at the bottom to about 5 nm at the tip. Electrochemical analysis reveals well-defined redox peaks of the [Fe(CN)(6)](3-/4-) redox couple and heterogeneous charge-transfer rate constants of 0.010 and 0.062 cm s(-1) for the cylindrical and conical nanofibers, respectively. The coverage of exposed edge planes on the cylindrical and conical carbon shells is estimated to be 2.5 and 15.5 % respectively. The more abundant exposed edge planes on the conical nanofiber decrease the overpotential and increase the voltammetric resolution during electrochemical detection of uric acid and ascorbic acid. Our results suggest that the density of edge-plane sites estimated from Raman scattering is not necessarily equal to the density of exposed edge-plane sites, and only carbon electrodes with a large density of exposed edge planes or free graphene sheet ends exhibit better electrochemical performance.

Soil physicochemical properties drive the variation in soil microbial communities along a forest successional series in a degraded wetland in northeastern China.

The Sanjiang Plain is the biggest freshwater wetland locating in northeastern China. Due to climate change and human activities, that wetland has degraded to a successional gradient from the original flooded wetland to dry shrub vegetation and a forest area with lower ground water level, which may result in changes in soil microbiologic structure and functions. The present study investigated the microbial diversity and community structure in relation to soil properties along that successional gradient. The soil physico-chemical properties changed significantly with degradation stage. The Shannon diversity index of both soil bacteria (5.90-6.42) and fungi (1.7-4.19) varied significantly with successional stage (both p < .05). The community structures of soil bacteria and fungi in the early successional stages (i.e., the wetland) were significantly determined by water content, total nitrogen, and available nitrogen concentrations in soils, while those in the later successional stages (i.e., forests) were significantly structured by soil organic carbon, soil pH, and available phosphorus concentrations. These results suggest that the soil microbial structure is mainly determined by soil properties rather than by plant community such as plant species composition along successional stages.

Electrical conductivity in a non-covalent two-dimensional porous organic material with high crystallinity.

Electroactive macrocycle building blocks are a promising route to new types of functional two-dimensional porous organic frameworks. Our strategy uses conjugated macrocycles that organize into two dimensional porous sheets via non-covalent van der Waals interactions, to make ultrathin films that are just one molecule thick. In bulk, these two-dimensional (2D) sheets stack into a three-dimensional van der Waals crystal, where relatively weak alkyl-alkyl interactions constitute the interface between these sheets. With the liquid-phase exfoliation, we are able to obtain films as thin as two molecular layers. Further using a combination of liquid-phase and mechanical exfoliation, we are able to create non-covalent sheets over a large area (>100 µm2). The ultrathin porous films maintain the single crystal packing from the macrocyclic structure and are electrically conductive. We demonstrate that this new type of 2D non-covalent porous organic framework can be used as the active layer in a field effect transistor device with graphene source and drain contacts along with hexagonal boron nitride as the gate dielectric interface.