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Background Previous studies have shown that the risk of tuberculosis (TB) increases dramatically during adolescence. However, the burdens and trends of tuberculosis (TB) are poorly understood among them, especially in high-prevalence countries. Methods Based on the Global Burden of Disease (GBD) 2019, we analyzed the incidence and mortality of TB among young people globally and in five Asian countries from 1990 to 2019. The annual percentage change was calculated by joinpoint regression analysis to estimate the trends in the age-standardized incidence rate (ASIR) and age-standardized death rate (ASDR). Results The highest ASIR per 100,000 person-years in 2019 was in Mongolia [74 (95% uncertainty interval (UI), 51 to 105)], while the lowest was in Japan [4 (95% UI, 2 to 6)]. The highest ASDR per 100,000 person-years was in Mongolia [2 (95% UI, 1 to 3)], while the lowest was in Japan [0.009 (95% UI, 0.008 to 0.010)]. As the absolute number of cases and deaths decreased from 1990 to 2019, the ASIRs and ASDRs in all five countries also decreased. The decreasing trends were particularly significant in developed regions and varied across geographic regions. Conclusions This study may be crucial in helping policymakers make decisions and allocate appropriate resources toadolescent TB control strategies.

Hosts can initiate macroautophagy/autophagy as an antiviral defense response, while viruses have developed multiple ways to evade the host autophagic degradation. However, little is known as to whether viruses can target lipids to subvert autophagic degradation. Here, we show that a low abundant signaling lipid, phosphatidylinositol 3,5-bisphosphate (PtdIns(3,5)P

A field experiment was carried out to study the responses of soil respiration, soil C and N, composition of main microbial groups, enzyme activity, and microbial C source utilization to two organic amendments (i.e., straw and manure) added alone or combined with biochar for 9 months in an infertile soil. In comparison with the non-amended control, soil CO2 emission rates were significantly increased following straw and manure addition, but they were decreased by 19% and 36% on average when co-applied with biochar. Organic amendments significantly increased the size of labile C pool by 21%, total phospholipid-fatty acid (PLFA) concentrations by 32%, activities of α-glucosidase by 51%, β-glucosidase by 115%, β-D-cellobiosidase by 105%, β-xylosidase by 43%, phenol oxidase by 59%, and peroxidase by 91% on average relative to the non-amended control, whereas biochar co-application with organic amendments had no effect on soil PLFA concentrations but significantly decreased the enzyme activities by 38% and the sizes of labile C and N pools by 16% on average. The results of the substrate-induced respiration confirmed a lower capacity of biochar-treated soils to use the C sources of carbohydrates and carboxylic acids. Structural equation modeling indicated that the response of soil CO2 emission rates to organic amendment and biochar was directly linked to their effects on microbial activities. Therefore, our study demonstrated that biochar co-applied with straw or manure mitigated soil C loss by decreasing soil microbial activities.

What is already known about this topic? A passenger who was from the United States was taken to the hotel for the required isolation on November 13, 2020. During the quarantine she was diagnosed as the COVID-19 patient on November 15, 2020. Controlling the importation of COVID-19 remains a major challenge. What is added by this report? In this study, an epidemiological investigation was conducted for a confirmed case of COVID-19, including the treatment records in the hospital and 14-day travel trajectory before the onset of disease. What are the implications for public health practice? This study described an epidemiological investigation and management process on an imported case of COVID-19 and analyzed the test results, aiming to provide useful warnings to strengthen the capacity of public health system in response to the importation.

Changes in soil aggregation with biochar amendment have been investigated extensively, but how biochar affects the chemical composition of organic carbon (C) and biological binding agents in aggregates and their linkage with soil aggregate stability remains unclear. Soil samples were collected in a rice paddy treated with 0 (C0, control), 10 t ha

The small brown planthopper, Laodelphax striatellus (Fallén), is an important agricultural pest that causes significant losses by sucking and transmitting multiple plant viruses, such as rice black-streaked dwarf virus (RBSDV). Insecticides are commonly used to control planthoppers and cause the induction or overexpression of cytochrome P450 monooxygenases (P450s) from the CYP3 and CYP4 clades after insecticide application. However, little is known about the roles of insecticides and P450s in the regulation of viral replication in insects. In this study, RBSDV-infected L. striatellus were injected with imidacloprid, deltamethrin, pymetrozine, and buprofezin, respectively. The insecticide treatments caused a significant decrease in RBSDV abundance in L. striatellus. Treatment of piperonyl butoxide (PBO), an effective inhibitor of P450s, significantly increased the RBSDV abundance in L. striatellus. Fourteen P450 candidate genes in the CYP3 clade and 21 in the CYP4 clade were systematically identified in L. striatellus, and their expression patterns were analyzed under RBSDV infection, in different tissues, and at different developmental stages. Among the thirty-five P450 genes, the expression level of CYP6CW1 was the highest, while CYP6AY3 was the lowest after RBSDV infection. Knockdown of CYP6CW1 and CYP6AY3 significantly increased the virus abundance and promoted virus replication in L. striatellus. Overall, our data reveal that CYP6CW1 and CYP6AY3 play a critical role in the regulation of virus replication in L.striatellus.

Soil extracellular enzyme activities among aggregate fractions are critical to short-term microbial activity and long–term carbon dynamics in forest ecosystems, but little is known regarding the effects of forest types on the soil enzyme activities in different soil aggregate fractions. Three typical subtropical forest types (Broadleaved forest, Moso bamboo forest and Chinese fir forest) were selected, and undisturbed soil samples (0–15 cm) were collected. We investigated the effects of forest types on aggregate stability (mean weight diameter, geometric mean diameter and fractal dimension), aggregate–associated organic carbon (OC) and the functionality of five enzymes (cellobiohydrolase, β-glucosidase, β-xylosidase, N–acetylglucosaminidase, leucine aminopeptidase) of different aggregate fractions (>2 mm, 0.25–2 mm, 0.053–0.25 mm and

The role of soil organic C (SOC) quality affecting microbial community composition and function under biochar application is poorly understood. We investigated the relationship between the pool size and chemical composition of SOC; composition of main microbial groups; enzyme activities involved in C, N, and P cycling; and soil respiration in a rice paddy amended with biochar for 20 months in a laboratory experiment at 15, 25, and 35 °C. Soil labile and recalcitrant organic C pools were determined by a two-step sulfuric acid (H2SO4) hydrolysis method. The chemical composition of SOC was determined with 13C-nuclear magnetic resonance spectroscopy. The biochar amendment at 20 and 40 t ha−1 significantly decreased the soil labile C pool I (extracted by 5 N H2SO4), alkyl, and carbonyl C contents and increased the recalcitrant C pool (acid-resistant) and aromatic C contents and the aromatic C to O-alkyl C ratio. The phospholipid-fatty acid concentrations and soil enzyme activities were unchanged by biochar application at 10 and 20 t ha−1, but both were increased at 40 t ha−1. Biochar increased the ratio of gram-positive (G+) to gram-negative (G−) bacteria and decreased that of fungi to bacteria. The recalcitrant C pool and aromatic C contents were positively correlated to the G+ bacteria abundance and were important factors in shaping composition of the main microbial groups and improving enzyme activities. Biochar application at 40 t ha−1 lowered soil respiration rates at 15 and 25 °C by decreasing labile C pool and increasing C recalcitrancy while increased temperature sensitivities of soil respiration at 25/15 °C and 35/25 °C by stimulating microbial abundance and enzyme activities. Together, our results suggest that biochar soil amendment shifted microbial community composition and function through influencing the composition of SOC.

Background MicroRNAs (miRNAs), a class of small non-coding endogenous RNAs, play key roles in various biological processes. Most plant viruses are transmitted by insect vectors. However, little is known about the function of miRNAs on plant virus-insect host interaction. Results We investigated the role of miR-315-5p in regulation of plant viral infection in insects using a rice black-streaked dwarf virus (RBSDV) and small brown planthopper (SBPH) interaction system. Our results showed that miR-315-5p had the highest expression level in 2nd-instar nymph, and was highly expressed in the salivary gland and midgut in SBPH. miR-315-5p was in response to and regulated RBSDV infection in SBPH. Injection of miR-315-5p mimic, agomir-315, significantly increased the RBSDV accumulation, whereas injection of miR-315-5p inhibitor, antagomir-315, reduced virus accumulation in SBPH. Furthermore, a melatonin receptor was identified as a target gene of miR-315-5p by the dual luciferase reporter assay. Knockdown of the melatonin receptor significantly increased the expression of RBSDV coat protein gene S10 and replication related genes, S5-1, S6, and S9-1. Furthermore, treatment with melatonin receptor antagonist luzindole and activator agomelatine significantly increased and reduced RBSDV accumulation in SBPH, respectively. Compared to the control, miR-315-5p did not affect the efficiency of RBSDV acquisition in SBPH. However, the efficiency of RBSDV transmission was significantly reduced after injecting antagomir-315. Conclusion Taken together, our data reveal that miR-315-5p is beneficial for RBSDV infection in its insect vector by directly targeting a melatonin receptor. These findings provide a new insight to the function of miRNAs in virus-insect vector interaction. © 2021 Society of Chemical Industry.

Plant invasion can markedly alter soil fungal communities and nitrogen (N) availability; however, the linkage between the fungal decomposition capacity and N mineralization during plant invasion remains largely unknown. Here, we examined the relationship between net mineralization rates and relevant functional genes, as well as fungal species composition and function following Moso bamboo (Phyllostachys edulis) invasion of evergreen broadleaf forests, by studying broadleaf forests (non-invaded), mixed bamboo-broadleaf forests (moderately invaded) and bamboo forests (heavily invaded). Fungal species composition and functional genes involved in organic matter decomposition (laccase and cellobiohydrolase), N mineralization (alkaline peptidases) and nitrification (ammonia monooxygenase) were determined via high-throughput sequencing and real-time PCR. Both net ammonification and nitrification rates were generally increased with bamboo invasion into the broadleaf forest, where the net ammonification rate, on average, was 10.8 times higher than the nitrification rate across the three forest types. The fungal species composition and ecological guilds were altered with bamboo invasion, as demonstrated by the increased proportion of saprotrophs but decreased proportion of symbiotrophs in the bamboo forest. The increased net ammonification rate in bamboo forest was positively correlated with both fungal species composition and functional groups, and the fungal lcc gene (for lignin breakdown) abundance explained 67% of the variation of the net ammonification rate. In addition, the gene abundance of ammonia-oxidizing bacteria (AOB) explained 62% of the variation of net nitrification rate across the three forest types. The increased soil ammonification and nitrification rates following bamboo invasion of broadleaf forests suggest that the bamboo-invasion associated increase in soil N supply provided a positive feedback that facilitated bamboo invasion into broadleaf forests.

The fixation of atmospheric CO2 and N2 by soil bacteria is important to the terrestrial carbon (C) and nitrogen (N) cycles and can be greatly affected by anthropogenic disturbance. The application of mineral fertilizer combined with manure (MCM) instead of MF have been used to mitigate soil degradation caused by long term mineral fertilizer (MF) practiced in widely distributed Moso bamboo. We conducted an investigation, employing the statistical approach of space-for-time substitution, to evaluate the effect of MCM on soil CO2 and N2 fixation bacteria in subtropical region of China. Intensively managed Moso bamboo plantations receiving MCM for 0, 6, 10, 15, and 20 years were examined. MCM management enhanced the content of soil organic C and available soil N, P, K, although some fluctuating values were observed. Soil pH values were generally stable, ranging between 5.0 and 5.5. The abundance of the genes cbbL and nifH decreased significantlyafter 6 years of IM and then gradually recovered. Both CO2 and N2 fixation bacteria have their similar dominant species, such as Bradyrhizobium, but these differed in their relative abundances among treatments. The diversity of both bacterial groups either decreased or increased at the 10-year sampling and later returned to their original levels. The alterations of abundances and measures of community diversity for both CO2 and N2 fixation bacteria were not driven by unique factor. In conclusion, IM practice with MCM in Moso bamboo plantation had an overall positive effect on soil CO2- and N2-fixing bacteria as well as soil properties.

Bamboo is an important forest resource in many countries that serves as an excellent substitute for timber products and provides a multitude of other food and non-food uses. This societal and economic significance has led to increased bamboo cultivation globally. This review describes the rapid expansion of bamboo hectarage, both intentional and by encroachment, in native and non-native countries. Also presented are details of the influence of bamboo invasion on biodiversity and soil processes as well as potential ecological risk. Finally, we suggest some strategies for controlling bamboo invasion and needs for further research. Keywords: Biological invasion, Ecological risk, Environmental degradation, Monoculture

High waxy crude oil occupies an important proportion in oil resources, and its output is increasing year by year. At the temperature below the wax precipitation point, the wax in crude oil will precipitate and cross-link to form a spatial network structure, resulting in the gelation of crude oil. Once crude oil is gelled, it will exhibit viscoelastic-thixotropic characteristics, which will seriously affect the safety of crude oil pipeline transportation. In this paper, based on the principle of mechanical analogy, the elasticity, viscosity and structural strength of the gelled crude oil are characterized by springs, viscous pots, and structural parameters, respectively. On this basis, the viscoelastic-thixotropic model of waxy crude oil with 9 parameters is established. Meanwhile, the model applicability is verified by experimental data using two waxy crude oils under constant shear stress, shear stress step increase and shear stress hysteresis. Compared with the models in literatures, our model has clear physical meaning, relatively few parameters and high prediction accuracy.

Carbon (C) storage in forest soils can be enhanced through increasing organic C input and decreasing soil heterotrophic respiration (RH). The inhibitory effect of biochar on RH has been extensively studied in agricultural soils, while such an effect and the mechanisms involved remain unknown in forest soils. Here, we examine the response of soil physicochemical and microbial properties to biochar application and how these factors mediate the biochar-induced change in soil RH in a subtropical bamboo plantation. Our results showed that biochar application significantly reduced RH, and markedly altered most of the studied soil properties important for RH in the bamboo plantation. Biochar application did not affect soil temperature and no relationship between soil RH and either soil moisture or labile organic C content was observed, excluding the possibility that biochar reduced the RH through changing soil temperature, moisture or labile organic C content, factors commonly considered to control RH. As compared to the control, biochar application significantly increased the aromatic C content and RubisCO enzyme activity, while decreased β-glucosidase and cellobiohydrolase (CBH) activities. In addition, the soil RH was positively (P

Plant invasion can alter the soil microbial community and carbon cycling in terrestrial ecosystems; however, shifts in soil autotrophic bacterial communities and their driving environmental factors after plant invasion remain largely unknown. This study examined the relationship between Moso bamboo (Phyllostachys pubscens) invasion into broadleaf forests and autotrophic bacterial community composition-function at two field sites. The abundance and composition of autotrophic bacteria were characterized by real-time PCR, terminal restriction fragment length polymorphism, and clone library based on the cbbL gene that encodes ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO). On average, the cbbL gene abundance was 89% higher and RubisCO enzyme activity 110% higher in the bamboo forest than in the broadleaf forests across the two field sites. The cbbL gene abundance was positively correlated with the RubisCO enzyme activity. The cbbL-containing communities were dominated by the order Rhizobiales, and their composition differed between the forest types and between the two sites, with the effect of site location being greater. Soil readily-oxidizable carbon concentration was a critical factor determining the site location effect on the diversity and activity of the cbbL-containing community. Greater abundance and activity of autotrophic bacteria were associated with bamboo invasion into broadleaf forests, implying that such invasions are expected to increase the CO2 fixation potential.

Moso bamboo (Phyllostachys edulis) invasions into adjacent forests have been reported to threaten aboveground biodiversity and alter belowground soil processes. However, the impacts of bamboo invasion on soil microbial community composition, co-occurrence network and enzyme activity remain largely unknown. We presented a cross site field investigation on soil bacterial and fungal communities and enzyme activities in three forests (an original broadleaf forest, a mixed bamboo-broadleaf forest and a pure bamboo forest) at three sites in South China. Our results showed that bamboo invasion consistently increased soil pH (by 6.72% − 17.56%) and soil organic carbon concentrations (by 11.75% − 40.63%) across the three sites. Bamboo invasion consistently decreased fungal ITS gene abundances across the sites, but had little effect on bacterial 16S rRNA gene abundances and diversity indices. The community composition of both bacteria and fungi and their functional guilds differed among the three sites and were significantly (P

Plant viruses trigger numerous responses in their insect vectors. Using iTRAQ-based quantitative proteomics analysis, early responses of the insect vector, the small brown planthopper (Laodelphax striatellus Fallén, SBPH), after acquiring Rice black-streaked dwarf virus (RBSDV) at 3 days and 5 days post first access to diseased plants (padp) were revealed. A total of 582 differentially abundant proteins (DAPs) in SBPH with a fold change1.500 or0.667 (p-value 0.05) were identified. The proteomic analysis in SBPH at 3 days padp revealed 106 highly abundant proteins and 193 of low abundance, while 5 days padp revealed 214 highly abundant proteins and 182 of low abundance. Among them, 51 highly abundant proteins and 42 of low abundance were shown consistently at both 3 days and 5 days padp. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis mapping and Gene Ontology (GO) term classification suggested impairment of mitochondria in SBPH after RBSDV acquisition, and the 77 out of 582 differentially abundant SBPH proteins analyzed by the STRING program revealed the interaction network of the mitochondrial DAPs, showing an overall down-regulation of mitochondrial proteins including the electron transport chain proteins and mitochondrial ribosome proteins. The high abundance of Parkin at 5 days padp suggests that activation of mitophagy induced degradation of mitochondria occurred. Further verification of autophagy/mitophagy-related genes by reverse-transcription quantitative RT-PCR (RT-qPCR) in SBPH after RBSDV acquisition showed up-regulation of the autophagy receptors Optineurin (OPTN), Sequestosome-1 (SQSTM1, also known as p62) and Tax1-binding protein 1 (TAX1BP1) which targets ubiquitinated damaged mitochondria during mitophagy. The phosphorylation of the three autophagy receptors may be up-regulated through an increase of transcription level TRAF-associated NFκB activator (TANK)-binding kinase 1 (TBK1). As a result, an overall reduction in the abundance of mitochondrial proteins was observed and the selective autophagic degradation was up-regulated through increased transcription level of OPTN, p62/SQSTM1, TAX1BP1 and TBK1. Therefore, acquisition of RBSDV associated with up-regulated autophagy and selective mitochondrial degradation in SBPH suggest prevention of mitochondrial-mediated apoptosis and extension of the vector life span. BIOLOGICAL SIGNIFICANCE: RBSDV causes severe yield loss in rice plants. RBSDV is transmitted efficiently only through SBPH. It is important to understand how RBSDV infects SBPH in a persistent, circulative and propagative manner. However, there has been no study on the interaction between RBSDV and SBPH at the early acquisition stage using a proteomics approach. In this study, we combined iTRAQ technique and LC-MS/MS to analyze the vector proteomics at both the initial and latent infection stages after RBSDV acquisition and verified the results by RT-qPCR. Our results revealed that significantly low DAPs were involved in various pathways, including biosynthesis of secondary metabolites, ribosomes, carbon metabolism, biosynthesis of amino acids and TCA cycle. Further clustering of the DAPs revealed significant changes in SBPH mitochondria, including decreased proteins in mitochondrial ribosomes and electron transport chain complex I, II and V. On the other hand, there was a high abundance of Parkin, suggesting the occurrence of mitochondria damage and subsequent Parkin-mediated mitophagy for clearance of impaired mitochondria. Moreover, the decreased level of PMPCB in terms of gene expression and protein abundance suggested decreased PINK1 turnover, promoting Parkin/PINK1-mediated mitophagy. Further analysis on autophagy/mitophagy-related gene transcription level indicated up-regulation of OPTN, p62/SQSTM1, TAX1BP1 and TBK1, promoting selective autophagy in SBPH after RBSDV acquisition. These findings provided new insights into the effects of RBSDV on SBPH after early acquisition by selective degradation of mitochondria, especially on reprogramming of energy metabolism and decreased mitochondria biogenesis, to prevent apoptosis and prolong the life span of SBPH post virus acquisition.

Moso bamboo (Phyllostachys pubescens) is a fast-growing species that can invade neighboring forests through its vigorous rhizome system, leading to large shifts of plant diversity and soil properties. A primary concern is the response of arbuscular mycorrhizal fungal (AMF) communities and related soil C sequestration to bamboo forest expansion. We used a long-term soil chronosequence from primary broadleaved forest to moso bamboo forest to examine the changes in AMF abundance and communities, as well as their role in soil C storage. AMF communities showed strong niche differentiation, and were highly structured by forest type (r 2 = 0.648, P = 0.001), and marginally correlated to soil pH and organic C. Bamboo forest expansion increased soil AMF biomass as indicated by neutral lipid fatty acids (NLFA) 16:1ω5 abundance, easily extracted glomalin-related soil protein (EE-GRSP), and water-stable macroaggregates. We observed that soil AMF biomass contributed substantially to both soil macroaggregates and EE-GRSP, which were tightly correlated with soil organic C. The influence of bamboo forest expansion on soil C sequestration was mainly due to its indirect effect on AMF biomass. Bamboo forest expansion significantly changed soil AMF communities and increased AMF biomass, which in turn contributed to enhanced soil aggregation and C storage.

Intensive management practices, such as inorganic fertilization, soil tillage and understory removal, have been widely used to increase bamboo products and economic return in Moso bamboo ( Phyllostachys pubescens ) forests. Arbuscular mycorrhizal fungi (AMF) play a critical role in soil aggregation and carbon cycling. However, little is known about the effects of such long-term soil disturbance on soil AMF community composition and abundance, and their linkage to aggregation in Moso bamboo forests. We investigated soil chemical properties, water-stable soil aggregates, glomalin-related soil protein (GRSP), AMF community composition and biomass across a chronosequence of long-term intensively managed Moso bamboo forests (0, 10, 15, 20 and 25 years of intensive management) in a subtropical region of China. Our results showed that intensive management resulted in significant decreases in soil pH and high accumulations of soil available N, P and K contents. Both soil AMF biomass (indicated by neutral lipid fatty acid) and total GRSP content were significantly decreased with increasing duration under intensive management. High-throughput sequencing showed that intensive management greatly altered soil AMF community composition, and soil available N, P and K were important driving factors shaping it. Soil macroaggregate (>250 μm) proportion decreased by 20–29% in bamboo forest soils after 15 years of intensive management. Soil macroaggregate proportion and organic C content were found significantly and positively correlated with AMF biomass and total GRSP content, respectively, indicating a high risk of soil erosion and organic C depletion when AMF biomass was reduced in long-term intensively managed bamboo forests. In conclusion, our study suggests that long-term intensive management induced alterations in abundance and community composition of AMF are responsible for the decrease in soil aggregation in the Moso bamboo forests. Alternative management practices, such as reduced tillage and organic amendments, are urgently needed to improve AMF community in order to enhance soil aggregation and C sequestration in Moso bamboo forests.

Soil fungi play an important role in decomposing soil organic matter and facilitating nutrient uptake by plants, however, the relationship between fungal community and soil biogeochemical cycling during plant invasion is poorly understood. The objective of this study was to investigate the effects of Moso bamboo (Phyllostachys edulis) invasion into broadleaf forests on the soil organic C (SOC) chemical composition, fungal community and mineral N production. We collected soil samples in evergreen broadleaf forests, mixed bamboo-broadleaf forests and bamboo forests. Soil fungal community and SOC chemical composition were determined. Bamboo invasion decreased alkyl C but increased O-alkyl C contents. Soil fungal abundance (18S rRNA) was decreased, while their alpha diversity was increased by bamboo invasion. Additionally, bamboo invasion enhanced net N mineralization rate but reduced gross nitrification rate. The fungal community composition strongly correlated with alkyl C content, and alkyl C content explained 32% of the variation in the fungal abundance. Fungal community composition correlated with gross nitrification rate, with 43% of the variation in gross nitrification rate attributable to soil fungal abundance. Changes in soil fungal community caused by bamboo invasion into broadleaf forests were closely linked to changed soil organic C chemical composition and decelerated nitrate production.

Intensive forest management practices such as organic mulching and heavy fertilization can affect soil microbial composition and function, and soil organic carbon (SOC) forms. However, the linkage between soil microbial community composition and SOC forms is poorly understood in bamboo ( Phyllostachys praecox ) plantations under intensive management (mulching and fertilization). We examined the relationship between SOC (solid state 13 C NMR) and fungal community compositions (real-time PCR, terminal restriction fragment length polymorphism, and clone library) in a chronosequence of intensively managed bamboo plantations (0, 1, 6, 10, and 15 years of stand age). The fungal community composition (internal transcribed spacer, ITS) and function (cellobiohydrolases, cbhI ) and C forms in the top- (0–20) and subsoils (20–40 cm) were determined as fungi dominate cellulose (the main component of plant residues) decomposition in the soil. Soil fungal abundance (copy number of 18S rRNA) was positively correlated to O -alkyl C and aromatic C while negatively correlated to alkyl-C and carbonyl C concentrations. The alkyl C was the most influential SOC fraction on fungal community composition before intensive plantation management was applied, while O -alkyl C was the most influential C-form after more than 5 years of intensive management. The alkyl C, O -alkyl C, aromatic C and carbonyl C together explained 63.2 and 54.2% of the variations in total fungal composition in the top- and subsoils, respectively. Saprotrophic or cellulose-degrading species, mainly Mortierellales sp., Trichoderma sp. and Scheffersomyces sp., dominated the fungal community and the dominance increased with increasing plantation age (combined effects of stand age and duration of intensive management). The increased O -alkyl C concentration caused by increased plantation age explained shifts in the cbhI -containing community composition. Both the cbhI abundance and readily oxidizable C concentration increased with increasing plantation age in the topsoil but not in the subsoil. We conclude that in the intensively managed bamboo plantations changes in organic C forms were closely linked to changes in soil fungal community composition; such linkages have implications for soil nutrient cycling and C transformation in the plantation ecosystem.

Integrating land use type and other geographic information within spatial interpolation has been proposed as a solution to improve the performance and accuracy of soil nutrient mapping at the regional scale. This study developed a non–algorithm approach, i.e., applying inverse distance weighting (IDW) and ordinary kriging (OK), to individual land use types rather than to the whole watershed, to determine if this improved the performance in mapping soil total C (TC), total N (TN), and total P (TP) in a 200–km2 urbanizing watershed in Southeast China. Four land use types were identified by visual interpretation as forest land, agricultural land, green land, and urban land. One hundred and fifty soil samples (0–10 cm) were taken according to land use type and patch size. Results showed that the non–algorithm approach, interpolation based on individual land use types, substantially improved the performance of IDW and OK for mapping TC, TN, and TP in the watershed. Root mean square errors were reduced by 3.9% for TC, 10.7% for TN, and 25.9% for TP by the application of IDW, while the improvements by OK were slightly lower as 0.9% for TC, 7.7% for TN, and 18.1% for TP. Interpolations based on individual land use types visually improved depiction of spatial patterns for TC, TN, and TP in the watershed relative to interpolations by the whole watershed. Substantial improvements might be expected with denser sampling points. We suggest that this non–algorithm approach might provide an alternative to algorithm–based approaches to depict watershed–scale nutrient patterns.

Biochar incorporated into soil has been known to affect soil nutrient availability and act as a habitat for microorganisms, both of which could be related to its particle size. However, little is known about the effect of particle size on soil microbial community structure and function. To investigate short-term soil microbial responses to biochar addition having varying particle sizes and addition rates, we established a laboratory incubation study. Biochar produced via pyrolysis of bamboo was ground into three particle sizes (diameter size Phyllostachys praecox ) plantation soil. The results showed that the fine particle biochar resulted in significantly higher soil pH, electrical conductivity (EC), available potassium (K) concentrations than the medium and coarse particle sizes. The fine-sized biochar also induced significantly higher total microbial phospholipid fatty acids (PLFAs) concentrations by 60.28% and 88.94% than the medium and coarse particles regardless of addition rate, respectively. Redundancy analysis suggested that the microbial community structures were largely dependent of particle size, and that improved soil properties were key factors shaping them. The cumulative CO 2 emissions from biochar-amended soils were 2–56% lower than the control and sharply decreased with increasing addition rates and particle sizes. Activities of α-glucosidase, β-glucosidase, β-xylosidase, N -acetyl-β-glucosaminidase, peroxidase and dehydrogenase decreased by ranging from 7% to 47% in biochar-amended soils over the control, indicating that biochar addition reduced enzyme activities involved carbon cycling capacity. Our results suggest that biochar addition can affect microbial population abundances, community structure and enzyme activities, that these effects are particle size and rate dependent. The fine particle biochar may additionally produce a better habitat for microorganisms compared to the other particle sizes.

The reverse transcription quantitative polymerase chain reaction (RT-qPCR) has been widely used to determine gene functions in Laodelphax striatellus (Fallén) (small brown planthopper). Selection of suitable reference gene(s) for normalizations of RT-qPCR data is critical for reliable results. To date, reports on identification of suitable L. striatellus reference genes are still very limited. L. striatellus is a destructive rice pest and it can transmit multiple viruses, including Rice black-streaked dwarf virus (RBSDV), Rice stripe virus (RSV), and Maize rough dwarf virus (MRDV), to many important cereal crops worldwide. In this study, we examined the stablity of seven selected candidate reference genes in L. striatellus at different developmental stages, in different tissues, in RBSDV- or RSV-infected L. striatellus or in RBSDV-infected and Lssynaptojanin 1 (LsSYNJ1)-silenced L. striatellus. The RT-qPCR data representing individual candidate genes were analyzed using five different methods: the delta Ct method, geNorm, NormFinder, BestKeeper, and the RefFinder algorithm, respectively. The most stable reference gene for the specific condition was selected according to a comprehensive analysis using the RefFinder method. Ribosomal protein L5 (LsRPL5) and LsRPL8 are the most stably expressed genes in L. striatellus at different developmental stages. Alpha-1-tubulin (Lsα-TUB) is the most stably expressed reference gene in different tissues of RBSDV viruliferous (RBSDV-V) or non-viruliferous (RBSDV-NV) L. striatellus. LsRPL8 is the most stably expressed reference gene in RBSDV-V or RSV viruliferous (RSV-V) L. striatellus, while beta-tubulin (Lsβ-TUB) is the most stably expressed reference gene in RBSDV-V and LsSYNJ1-silenced L. striatellus. The selected reference genes were further investigated during analyses of RBSDV P5-1 and P10 gene expression in different tissues from RBSDV-V or RBSDV-NV L. striatellus. The stably expressed reference genes identified in this study will benefit future gene function studies using L. striatellus.

Background: Fluconazole resistance in Candida albicans has become a serious public health problem. Most previous studies have focused on deciphering the relationship between fluconazole resistance and amino acid substitutions in ERG11, which encodes cytochrome P450 lanosterol 14α-demethylase whose enzymatic activity is inhibited by azoles. However, azole resistance in C. albicans is a multifactorial phenomenon and several lines of evidence indicate that other genes and mechanisms may contribute to the development of fluconazole resistance. Objectives: The present study aimed to investigate the underlying role of six genes in fluconazole-resistant clinical strains of C. albicans, including ERG11, RTA2, and the efflux pump genes CDR1, CDR2, MDR1, and FLU1. Methods: We collected 40 fluconazole-resistant isolates and 40 susceptible isolates from patients with Candida infections in the First Affiliated Hospital of Nanchang University in China from 2005 to 2008. The susceptibility of the isolates to antifungal agents was tested by the M27-A3 broth microdilution method following the Clinical and Laboratory Standards Institute (CLSI) guidelines. Then, the gene expression levels of several key players in azole resistance were quantified. Results: Most fluconazole-resistant strains analyzed in this study were found to be cross-resistant to ketoconazole, itraconazole, and clotrimazole. We observed that the FLU1 gene expression significantly increased (P < 0.05) and exhibited major changes in most of the fluconazole-resistant isolates (75.0%). In addition, the expression of a novel gene, RTA2, was remarkably upregulated (P < 0.05). Interestingly, we found that 10% of the fluconazole-resistant isolates were simultaneously associated with ERG11 mutation and overexpression of RTA2, CDR1, and FLU1 genes. Unlike other studies, we did not find any difference in the expression of CDR2, MDR1, and ERG11 genes between the fluconazole-susceptible and resistant isolates. Conclusions: Our findings suggested that the overexpression of FLU1 and RTA2 genes may cause azole resistance; this finding had not been reported previously in clinical isolates of C. albicans. The upregulation of FLU1 and RTA2 genes was the predominant mechanism of fluconazole resistance in C. albicans in China.

Long-term intensive management, such as inorganic fertilization and soil tillage, have been reported to decrease soil organic carbon content (SOC) and diversity of soil bacterial communities, as well as increase N2O emissions in moso bamboo forests. However, the response of the N-cycling soil microbial community to intensive management remains unclear. To address this, we examined the effects of intensive moso bamboo management on nitrifying and denitrifying microorganisms. Soils receiving non-management (NM) and 10, 15, 20, and 25 years of intensive management (IM10, IM15, IM20, IM25) were characterized using quantitative real-time PCR (qPCR) and high-through sequencing methods. Our results showed that abundances of ammonia monooxygenase (amoA) from ammonia-oxidizing archaea (AOA) significantly increased (P

Root-associated fungal communities play a key role in plant productivity and soil processes in forest ecosystems. However, how diversity and composition of root-associated fungi change with forest development and their linkage with soil enzyme activities remain largely unknown. We characterized the root-associated fungal communities, plant and soil properties, and extracellular enzyme activities along a chronosequence spanning young (15 years old) to over-mature (63 years old) Pinus massoniana forest development stages. Our results showed that P. massoniana roots harbored diverse root-associated fungal communities and they varied with forest development. Near-mature (36 years old) forest stands had the lowest alpha-diversity but higher relative abundances of ericoid mycorrhizal and activities of enzymes involved in C, N and P acquisition. The relative abundances of ectomycorrhizal fungi and endophyte were higher in middle-age (24 years old) and mature stands (45 years old), whereas the relative abundance of ericoid mycorrhizal fungi was highest in the near-mature stand. Soil pH, soil C:P and N:P ratios were important factors shaping the diversity and composition of root-associated fungal communities. Structural equation modeling indicated that changes in the community composition, but not richness of root-associated fungi, had significant correlations with soil enzymatic C:N and N:P stoichiometry. In conclusion, this study suggests that different stand development stages exhibit distinct diversity and composition of root-associated fungal communities, which affecting soil functions in terms of enzymatic activity.

Summary The canker disease caused by Botryosphaeria dothidea in China has resulted in serious damage and death to Carya cathayensis and continues to expand its range. A Bacillus strain, designated Bacillus amyloliquefaciens subsp. plantarum CGMCC 11640, was successfully screened from 103 field isolates from local soils by a plate dual-culture method. It showed inhibition zones between B. dothidea and CGMCC 11640 in vitro. From a methyl alcohol extract of the filtrate, the antifungal compounds were identified as a series of lipopeptides by HPLC, namely fengycins, surfactins and iturins, with fengycins being the dominant component. The fengycins were further identified by LC–MS to be a mixture of C15, C16, C17 and C18 fengycin A and their isomers (normal, iso and anteiso). The strong anti-B. dothidea activity indicated that the B. amyloliquefaciens subsp. plantarum CGMCC 11640 and its bioactive components might provide an alternative bioresource for the biocontrol of C. cathayensis canker.