The gut bacterial flora associated with brown planthopper is affected by host rice varieties.

Gut microbiota plays vital roles in the development, evolution and environmental adaptation of the host insects. The brown planthopper (BPH) is one of the most destructive pests of rice, but little is known about its gut microbiota. In this study, we investigated the gut bacterial communities in two BPH populations feeding on susceptible and resistant rice varieties by high-throughput amplicon sequencing. Our results revealed that the gut bacterial communities in BPH were species diverse. A total of 29 phyla and 367 genera were captured, with Proteobacteria and Acinetobacter being the most prominent phylum and genus, respectively. Comparative analysis showed that significant differences in the profile of gut bacterial communities existed between the two BPH populations. The species richness detected in the population feeding on the resistant rice variety was significantly higher than that in the population rearing on the susceptible rice variety. Although the most dominant gut bacteria at all taxonomic levels showed no significant differences between the two BPH populations, the relative abundances of two subdominant phyla (Firmicutes and Bacteroidetes) and two subdominant classes (Bacteroidia and Clostridia) were significantly different. FAPROTAX analysis further indicated that host rice varieties might induce changes of the gut bacterial flora in BPH, as significant differences in five metabolism-related functional categories (fermentation, methylotrophy, xylanolysis, nitrate reduction and ureolysis) were detected between the two BPH populations. Our results are informative for studies which focused on the interactions between BPH and its symbiotic microbes and could also provide the basis of future BPH biological management.

The Non-Concentration-Quenching Phosphor Ca3Eu2B4O12 for WLED Application.

Commercial white LED devices usually suffer from a high color temperature and poor color rendering. Developing a new, efficient, and stable red phosphor is the key to solving this problem. In this work, a series of pure Ca3Y2-xB4O12:xEu3+ (0 < x ≤ 2) samples, including the new and fully transitional borate phosphor Ca3Eu2B4O12 (CEBO), have been successfully prepared by solid-state reaction synthesis. CEBO is isostructural with Ca3Y2B4O12 (CYBO), belonging to the orthorhombic system with space group Pnma (No. 62). Under optimal 393 nm excitation, this borate exhibits a strong red emission, peaking at 615 nm, with high color purity. Interestingly, the luminescence of CEBO is relatively higher than that of CYBO:Eu3+ phosphors. The quantum yield of this non-concentration-quenching phosphor reaches 95.6%. Furthermore, a warm pc-WLED device has been fabricated by mixing as-prepared CEBO powders and commercial BaMgAl10O17:Eu2+ and (Sr, Ba)2SiO4:Eu2+ phosphors, which exhibits a high color rendering index (Ra = 83.7) along with a color temperature of around 3883 K. The present work indicates that this new borate, with outstanding quantum efficiency and favorable thermal stability, can be used as a red phosphor for application in WLEDs.

Complete mitochodrial genome of the crab spider Ebrechtella tricuspidata (Araneae: Thomisidae): A novel tRNA rearrangement and phylogenetic implications for Araneae.

Mitochondrial genomes are widely used for phylogenetic and phylogeographic analyses among arthropods, but there is a lack of sufficient mitochondrial genome sequence data for spiders. Herein, we sequenced and characterized the complete mitochondrial genome of a crab spider Ebrechtella tricuspidata (Araneae: Thomisidae). The circular mitochondrial genome is 14,352 bp long, including a standard set of 37 genes and an A + T-rich region. Nucleotide composition is highly biased toward A + T nucleotides (77.3%). A novel gene order rearrangement is detected by a tRNA (trnL1) translocation. Tandem repeats are not identified in the A + T-rich region. Most of the tRNAs are greatly reduced in size and cannot be folded into typical cloverleaf-shaped secondary structures. The phylogenetic analysis confirms that the mitochondrial genome sequences are useful in resolving higher-level relationship of Araneae. Overall, our data present in this study will elevate our knowledge on the architecture and evolution of spider mitochondrial genome.

The complete mitogenome of a jumping spider Carrhotus xanthogramma (Araneae: Salticidae) and comparative analysis in four salticid mitogenomes.

The complete mitogenome of the jumping spider Carrhotus xanthogramma was determined and comparative analysis among four salticid mitogenomes was conducted. The circular genome is 14,563 bp in size and contains a complete set of genes that usually present in the metazoa. All of the 13 protein-coding genes begin with a typical ATN codon and stop with the canonical stop codons, except for ND4 and ND4L genes with an incomplete stop codon T. All of the tRNAs cannot be formed the fully paired acceptor stems and seven out of them cannot be folded into the typical cloverleaf-shaped secondary structures. The tRNA Glu gene translocates its position as compared to the mitogenomes of other three determined jumping spiders. The A+T content of the majority strand and the A+T-rich region are 75.1 and 80%, respectively. The phylogenetic relationships based on concatenated nucleotide and amino acid sequences of 13 protein-coding genes using Maximum Likelihood and Bayesian Inference methods indicated that mitogenome sequences were useful in resolving higher-level relationship of Araneae.

Novel Diterpenoids from the Twigs of Podocarpus nagi.

Phytochemical investigation of the twigs of Podocarpus nagi (Podocarpaceae) led to the isolation of two new abietane-type diterpenoids, named 1ß,16-dihydroxylambertic acid (1) and 3ß,16-dihydroxylambertic acid (2), along with two new ent-pimarane-type diterpenoids, named ent-2ß,15,16,18-tetrahydroxypimar-8(14)-ene (3) and ent-15-oxo-2ß,16,18-trihydroxypimar-8(14)-ene (4). Their respective structures were elucidated on the basis of spectroscopic analyses, including 1D- and 2D-NMR, IR, CD, and HR-ESI-MS. This is the first time ent-pimarane-type diterpenoids from the genus Podocarpus has been reported. All four new compounds were tested for cytotoxic activity. The MTT assay results showed that compounds 3 and 4 significantly inhibited the proliferation of human cervical cancer Hela cells, human lung cancer A549 cells, and human breast cancer MCF-7 cells at a concentration of 10 µM. Furthermore, using the lipopolysaccharide (LPS)-stimulated RAW264.7 cells, compounds 2 and 4 were found to significantly inhibit nitrogen oxide (NO) production with IC50 values of 26.5 ± 6.1 and 17.1 ± 1.5 µM, respectively.

The role of three calcineurin subunits and a related transcription factor (Crz1) in conidiation, multistress tolerance and virulence in Beauveria bassiana.

The eukaryotic calcineurin (CN) pathway comprising catalytic A (CnA) and regulatory B subunits (CnB) is crucial for many biological processes but functionally unexplored in entomopathogenic fungi. Here, we characterise three CN subunits (CnA1, CnA2 and CnB) and a downstream CN-responsive zinc finger transcription factor (Crz1) in Beauveria bassiana. CN-mediated phosphatase activity decreased by 16-38 % in all deletion mutants compared with wild type. Growth and conidiation were most defective in ΔcnB, which showed a large proportion of abnormally branched germlings but were less defective in ΔcnA1 and ΔcnA2. Conidiation defects also occurred in Δcrz1, uniquely accompanied with slower germination. Compared with wild type, the four deletion mutants became, to varying degrees, more sensitive to Ca(2+), Mn(2+), Zn(2+), Mg(2+), two oxidants, three cell wall stressors, carbendazim, heat shock and ultraviolet (UV)-B irradiation. They were also less virulent to Spodoptera litura larvae. Only ΔcnB and Δcrz1 were less tolerant to high osmolarity. The altered phenotypes of the deletion mutants were associated with lower intracellular mannitol and trehalose levels, reduced overall activity of superoxide dismutases and catalases, altered cell wall composition and down-regulation of numerous phenotype-influencing genes. Additionally, the transcription of six cascaded genes in two stress-responsive mitogen-activated protein kinase (MAPK) pathways and the phosphorylation of hallmarking Hog1 and Slt2 were largely down-regulated in all the deletion mutants under osmotic and cell wall stresses, respectively. All the changes were restored by gene complementation. Taken together, three calcineurin subunits and Crz1 play vital, but variable, roles in B. bassiana responses to environmental stresses during development and host signals during infection.

Bbssk1, a response regulator required for conidiation, multi-stress tolerance, and virulence of Beauveria bassiana.

Ssk1-type response regulator proteins are the core elements of histidine-to-aspartate systems that mediate fungal stress tolerance, a determinant to the biocontrol potential of fungal entomopathogens. We characterized the functions of Beauveria bassiana Ssk1 (Bbssk1) by analyzing multi-phenotypic changes in ΔBbssk1 and differentially expressed genes in the digital gene expression (DGE) libraries of ΔBbssk1 and wild-type constructed under osmotic stress. The Bbssk1 disruption caused 25 % reductions in conidial yield and virulence to Spodoptera litura larvae and significant defects in tolerances to two osmotic salts (81-84 %), H2O2 oxidation (23 %), two fungicides (21-58 %), three cell wall biosynthesis inhibitors (25-36 %), and three metal ions (~8 %) during colony growth, respectively, but little changes in cell sensitivity to menadione oxidation and in conidial thermotolerance and UV-B resistance. RNA-seq analysis with the DGE libraries revealed differential expressions of 1,003 genes in the ΔBbssk1 genome. Of those, many associated with conidiation, stress response, xenobiotic transport, cell wall integrity, and protein/carbohydrate metabolism were remarkably down-regulated, including the genes involved in mitogen-activated protein kinase (MAPK) signal pathway that downstream of Bbssk1. Our results indicate that Bbssk1 regulates positively the expressions of the MAPK cascade in the pathway of B. bassiana and many more downstream genes associated with conidiation, multi-stress tolerance, and virulence.

Catalases play differentiated roles in the adaptation of a fungal entomopathogen to environmental stresses.

The catalase family of Beauveria bassiana (fungal entomopathogen) consists of catA (spore-specific), catB (secreted), catP (peroxisomal), catC (cytoplasmic) and catD (secreted peroxidase/catalase), which were distinguished in phylogeny and structure and functionally characterized by constructing single-gene disrupted and rescued mutants for enzymatic and multi-phenotypic analyses. Total catalase activity decreased 89% and 56% in ΔcatB and ΔcatP, corresponding to the losses of upper and lower active bands gel-profiled for all catalases respectively, but only 9-12% in other knockout mutants. Compared with wild type and complement mutants sharing similar enzymatic and phenotypic parameters, all knockout mutants showed significant (9-56%) decreases in the antioxidant capability of their conidia (active ingredients of mycoinsecticides), followed by remarkable phenotypic defects associated with the fungal biocontrol potential. These defects included mainly the losses of 40% thermotolerance (45°C) in ΔcatA, 46-48% UV-B resistance in ΔcatA and ΔcatD, and 33-47% virulence to Spodoptera litura larvae in ΔcatA, ΔcatP and ΔcatD respectively. Moreover, the drastic transcript upregulation of some other catalase genes observed in the normal culture of each knockout mutant revealed functionally complimentary effects among some of the catalase genes, particularly between catB and catC whose knockout mutants displayed little or minor phenotypic changes. However, the five catalase genes functioned redundantly in mediating the fungal tolerance to either hyperosmotic or fungicidal stress. The differentiated roles of five catalases in regulating the B. bassiana virulence and tolerances to oxidative stress, high temperature and UV-B irradiation provide new insights into fungal adaptation to stressful environment and host invasion.

A Droplet Digital PCR-Based Approach for Quantitative Analysis of the Adulteration of Atlantic Salmon with Rainbow Trout.

Low-cost fish species are often used to adulterate or substitute for Atlantic salmon products, posing a serious threat to market order and public health. Hence, reliable techniques are urgently needed to detect Atlantic salmon adulteration. In this study, a precise method for identifying and quantifying adulterated Atlantic salmon with rainbow trout based on droplet digital PCR (ddPCR) testing was developed. Species-specific primers and probes were designed targeting the single-copy nuclear gene myoglobin of two salmonids. A quantitative formula for calculating the mass fraction of adulterated Atlantic salmon with rainbow trout was established based on a one-step conversion strategy, in which the DNA copy number ratios were directly transformed to meat mass fractions by introducing a fixed constant (the transfer coefficient). The dynamic range of the established ddPCR method was from 1% to 90%, with a limit of detection (LOD) of 0.2% and a limit of quantification (LOQ) of 0.8% for rainbow trout in Atlantic salmon, respectively. The quantification method demonstrated an acceptable level of repeatability and reproducibility, as the values of the relative standard deviation (RSD) for the tested meat mixtures with the known fractions were all less than 5%. Thermal and freezing treatments, as well as adding food additives within the recommended dosage limits, had no significant effect on the quantification accuracy. The method was successfully applied to detect rainbow trout adulteration in commercial raw and processed Atlantic salmon products. In comparison to real-time quantitative PCR (qPCR) testing, the established ddPCR method exhibited a higher level of stability and accuracy. Overall, the ddPCR-based quantitative method exhibited high levels of accuracy, stability, sensitivity, and practicability, suitable for applications in the routine surveillance and quality assurance of salmon products.

Characterization and transcriptomic analysis of a native fungal pathogen against the rice pest Nilaparvata lugens.

The brown planthopper (BPH), Nilaparvata lugens, is one of the most destructive pests of rice. Given the threats posed by insecticide resistance to its control, eco-friendly strategies based on microbial pathogens emerged as a promising biocontrol alternative. In the present study, we isolated a native fungal pathogen against BPH from infected BPH cadavers and preliminarily identified as a strain of Aspergillus fumigatus based on morphological and molecular methods. Laboratory bioassay revealed that this fungal strain was highly virulent to BPH both at nymphal and adult stages, with the median lethal times (LT50) of 7.5 and 5.8 days under high conidial concentration of 1 × 109 conidia mL-1. A genome-wide view of gene expressions in BPH against fungal attack was analyzed by transcriptomic sequencing and consequently a large number of differentially expressed genes that mainly involved in host immune defense and cell detoxification were found. RNAi-mediated knockdown of an upregulated gene encoding a serine protease (NlSPN) could cause a significant decrease in BPH survival. Combination of dsRNA injection and fungal infection showed an additive effect on BPH mortality, which provided clues to develop new pest management strategies against BPH.

Primary roles of two dehydrogenases in the mannitol metabolism and multi-stress tolerance of entomopathogenic fungus Beauveria bassiana.

Knockout and complement mutants of mannitol-1-phosphate dehydrogenase (MPD) and mannitol dehydrogenase (MTD) were constructed to probe the roles of both enzymes in the mannitol metabolism and multi-stress tolerances of entomopathogenic fungus Beauveria bassiana. Compared with wild-type and complement mutants, ΔBbMPD lost 99.5% MPD activity for reducing fructose-6-phosphate to mannitol-1-phosphate while ΔBbMTD lost 78.9% MTD activity for oxidizing mannitol to fructose. Consequently, mannitol contents in mycelia and conidia decreased 68% and 83% for ΔBbMPD, and 16% and 38% for ΔBbMTD, accompanied by greatly enhanced trehalose accumulations due to 81-87% decrease in their neutral trehalase expression. Mannitol as mere carbon source in a nitrate-based minimal medium suppressed the colony growth of ΔBbMTD instead of ΔBbMPD, and delayed more conidial germination of ΔBbMTD than ΔBbMPD. Based on median lethal responses, conidial tolerances to H(2) O(2) oxidation, UV-B irradiation and heat stress at 45°C decreased 38%, 39% and 22% in ΔBbMPD, and 18%, 16% and 11% in ΔBbMTD respectively. Moreover, ΔBbMPD and ΔBbMTD lost 14% and 7% of their virulence against Spodoptera litura larvae respectively. Our findings highlight the primary roles of MPD and MTD in mannitol metabolism and their significant contributions to multi-stress tolerances and virulence influential on the biocontrol potential of B.bassiana.

Impact of an indigenous microbial enhanced oil recovery field trial on microbial community structure in a high pour-point oil reservoir.

Based on preliminary investigation of microbial populations in a high pour-point oil reservoir, an indigenous microbial enhanced oil recovery (MEOR) field trial was carried out. The purpose of the study is to reveal the impact of the indigenous MEOR process on microbial community structure in the oil reservoir using 16Sr DNA clone library technique. The detailed monitoring results showed significant response of microbial communities during the field trial and large discrepancies of stimulated microorganisms in the laboratory and in the natural oil reservoir. More specifically, after nutrients injection, the original dominant populations of Petrobacter and Alishewanella in the production wells almost disappeared. The expected desirable population of Pseudomonas aeruginosa, determined by enrichment experiments in laboratory, was stimulated successfully in two wells of the five monitored wells. Unexpectedly, another potential population of Pseudomonas pseudoalcaligenes which were not detected in the enrichment culture in laboratory was stimulated in the other three monitored production wells. In this study, monitoring of microbial community displayed a comprehensive alteration of microbial populations during the field trial to remedy the deficiency of culture-dependent monitoring methods. The results would help to develop and apply more MEOR processes.

Comprehensive insights into host-pathogen interaction between brown planthopper and a fungal entomopathogen by dual RNA sequencing.

BACKGROUND: The brown planthopper (BPH) is one of the most destructive pests of rice, causing tremendous yield and economic losses every year. The fungal entomopathogen Metarhizium anisopliae was previously proved to have great potential for BPH biocontrol. Genome-wide insight into the insect-fungus interaction is crucial for genetic improvement of M. anisopliae to enhance its virulence to BPH but still has been poorly explored. RESULTS: Using dual RNA-seq approach, we present here a global view of host and fungal gene expressions in BPH adults during the fungal infection. The results revealed that BPH could initiate strong defense responses against the fungal attack by upregulating the expressions of a large number of genes, including genes involved in cuticle formation, immune response, cell detoxification and biomacromolecule metabolism. Correspondingly, the fungal entomopathogen could induce a series of genes to infect and modulate BPH, including genes involved in fungal penetration, invasive growth, stress resistance and virulence. Three host defense-related genes (NlPCE4, NlPOD1 and NlCYP4DE1) were chosen for further function analysis. RNAi-mediated knockdown of NlPCE4 caused a significant decrease in BPH survival, but no obvious effects on the survival rates were detected by the suppression of NlPOD1 and NlCYP4DE1. Combination of dsRNA injection and fungal infection could significantly enhance the BPH-killing speed, as synergistic mortalities were observed in co-treatments of RNAi and M. anisopliae infection. CONCLUSION: Our study provides a comprehensive insight into molecular mechanisms of host-pathogen interaction between BPH and M. anisopliae and contributes to future development of new efficient biocontrol strategies for BPH biocontrol.

Host-Plant Induced Shifts in Microbial Community Structure in Small Brown Planthopper, Laodelphax striatellus (Homoptera: Delphacidae).

Microbiome associated with insects play vital roles in host ecology and physiology. The small brown planthopper (SBPH), Laodelphax striatellus, is a polyphagous insect pest that caused enormous damage to a wide range of cereal crops. Previous studies have assessed the effects of environmental factors, such as antibiotics, insecticide, and geographical habitat on the bacterial composition of SBPH. However, the influence of host plants on the microbial community in SBPH still unclear. Here, we characterized and compared the microbial community in three SBPH populations feeding on rice, barley, and wheat, respectively, using high-throughput amplicon sequencing. Our observations revealed that the microbiome harbored by SBPH was abundant and diverse. Ten phyla comprising 141 genera of bacteria were annotated, and four fungal phyla consisting of 47 genera were assigned. The bacteria belonging to the phylum Proteobacteria were the most prevalent and the fungi with the highest abundance were from the order Hypocreales. Comparative analysis showed that host plants could significantly induce structural changes of SBPH microbiome. Significant differences in abundance were observed in two main bacterial orders (Rickettsiales and Rhodospirillales) and three fungal classes (Sordariomycetes, an unclassified class in Ascomycota and Eurotiomycetes) among three host-adapted SBPH populations. Our results could broaden our understanding of interactions among SBPH, its microbial associates and host plants, and also represented the basis of future SBPH biological management.

Cullin 4B regulates cell survival and apoptosis in clear cell renal cell carcinoma as a target of microRNA-217.

Cullin 4B (CUL4B) was reported to be closely related to the progression of some tumors, but its function in clear cell renal cell carcinoma (ccRCC) has not been reported. Our present study found CUL4B was upregulated in ccRCC, and CUL4B knockdown markedly inhibited ccRCC cell growth and induced apoptosis. In addition, CUL4B knockdown markedly inhibited antiapoptotic proteins' expression in ccRCC cells, including Mcl-1 and Bcl-2, and silenced CUL4B also induced the cleavages of PARP, an important index of apoptosis. We also confirmed microRNA-217 (miR-217) was downregulated in ccRCC tumor tissues, and negatively correlated with CUL4B expression. Further investigations revealed miR-217 targeted CUL4B and markedly inhibited its expression in ccRCC cells. In addition, overexpression of miR-217 by mimics significantly suppressed ccRCC cell growth. In contrast, enforced expression of CUL4B significantly abolished miR-217-induced cell survival inhibition in ccRCC cells. In conclusion, our present results suggested targeting miR-217-CUL4B axis would be a promising strategy for ccRCC treatment.

Hydrophobicity-related protein contents and surface areas of aerial conidia are useful traits for formulation design of fungal biocontrol agents.

To clarify the potential use of hydrophobicity-related traits of aerial conidia in formulation design of fungal biocontrol agents, hydrophobicity rates (H (r)) and surface areas (S (a)) of aerial conidia were assessed with 48 strains of Beauveria bassiana, Isaria fumosorosea and Metarhizium spp. Inter- or intra-specific variation was large in H (r) (59.7-92.2%) and S (a) (7.9-25.3 microm(2) conidium(-1)) measurements, which were significantly correlated (r (2) = 0.55). Six isolates of the three fungi with distinguished H (r) and S (a) were further studied. Conidial wall proteins of these isolates were sequentially extracted with sodium dodecyl sulfate (SDS), formic acid (FA) and trifluoroacetic acid (TFA). Their H (r) values were significantly correlated to the contents (P (c)) of TFA-soluble, but FA-insoluble, proteins (2.7-44.8 microg per 10(7) conidia; r (2) = 0.79) and reduced drastically by the FA/TFA treatments, which eliminated the hydrophobin-based rodlet layers of conidial surfaces. However, the SDS treatments had no effect on either H (r) or rodlet layers. The dispersancy of a tested emulsifier to oil formulations of the six isolates in water was adversely correlated to their H (r) (r (2) = 0.94). The results indicate that both P (c) and S (a) are inherent hydrophobicity-related traits and can be utilized to select fungal biocontrol candidates for improved formulation and application.

[A prospective controlled comparative study of Doppler-guided hemorrhoidal artery ligation versus operative procedures for prolapse and hemorrhoids].

OBJECTIVE: To compare the safety and efficacy of Doppler-guided hemorrhoidal artery ligation and operative procedures for prolapse and hemorrhoids. METHODS: Ninety-two cases with a diagnosis of hemorrhoids from June 1, 2006 to June 1, 2008 at our hospital were collected and divided into the observation group (A, n = 40) and the control group (B, n = 52). They received Doppler-guided hemorrhoidal artery ligation and operative procedures for prolapse and hemorrhoids respectively. The efficacy of two groups was compared with regards to efficacy, operative duration, postoperative pain score, postoperative analgesic use, postoperative complications, hospitalization duration, recovery time, total treatment expenditure, patient satisfaction and 1-year follow-up. RESULTS: After treatment, two groups demonstrated similar profiles of efficacy, operative duration, patient satisfaction and the relapsing rate at 1 year. Group A was obviously better than Group B. with regards to recovery time, hospitalization duration and total treatment expenditure. Furthermore the incidence of such complications as postoperative pain, urinary retention, anal bulge, hemorrhage, perianal infections, anal edema and anal fissure was lower. CONCLUSION: Doppler-guided hemorrhoidal artery ligation has many advantages, such as safety, effectiveness, less trauma, a quick recovery, less treatment expenditure and a lower incidence of complications. Thus it is worthy of a wider popularization. However, its long-term effect remains to be seen.

The zinc finger transcription factors Bbctf1α and Bbctf1ß regulate the expression of genes involved in lipid degradation and contribute to stress tolerance and virulence in a fungal insect pathogen.

BACKGROUND: To initiate insect infection, entomopathogenic fungi produce diverse cuticle-degrading enzymes. Of those, lipolytic enzymes participate in epicuticular lipid hydrolysis and thus facilitate fungal penetration through the outermost cuticular barrier of the insect host. The Far/CTF1-type zinc finger transcription factors play an important role in the regulation of lipolytic activity and fungal pathogenicity in plant pathogens but remain functionally unknown in fungal insect pathogens. RESULTS: Two Far/CTF1-type transcription factor Bbctf1α and Bbctf1ß, which are essential for differential expression of genes involved in the fungal lipid degradation, were identified and functionally characterized in a fungal entomopathogen Beauveria bassiana. Disruption of each gene led to drastic losses of extracellular lipolytic activities under lipidic substrate-inducing conditions, followed by remarkable phenotypic defects associated with the fungal biocontrol potential. These defects mainly included severe impairments of mycelial growth and conidium formation, and drastic losses of tolerance to the stresses of oxidation and cell wall perturbation during colony growth under either normal or induction conditions. Bioassays showed that the virulence of each disruption mutant on the greater wax moth was remarkably attenuated in topical immersion. However, there was no significant difference in intrahemolymph injection when the cuticle penetration process was bypassed. CONCLUSIONS: Bbctf1α and Bbctf1ß are multifunctional transcription factors that play vital roles in the regulation of fungal lipid utilization and contribute to the vegetative growth, sporulation capacity, environmental fitness and pest control potential in B. bassiana. © 2020 Society of Chemical Industry.

Diversity and dynamics of microbial communities in brown planthopper at different developmental stages revealed by high-throughput amplicon sequencing.

The microbiome associated with brown planthopper (BPH) plays an important role in mediating host health and fitness. Characterization of the microbial community and its structure is prerequisite for understanding the intricate symbiotic relationships between microbes and host insect. Here, we investigated the bacterial and fungal communities of BPH at different developmental stages using high-throughput amplicon sequencing. Our results revealed that both the bacterial and fungal communities were diverse and dynamic during BPH development. The bacterial communities were generally richer than fungi in each developmental stage. At 97% similarly, 19 phyla and 278 genera of bacteria were annotated, while five fungal phyla comprising 80 genera were assigned. The highest species richness for the bacterial communities was detected in the nymphal stage. The taxonomic diversity of the fungal communities in female adults was generally at a relatively higher level when compared to other developmental stages. The most dominant phylum of bacteria and fungi at each developmental stage all belonged to Proteobacteria and Ascomycota, respectively. A significantly lower abundance of bacterial genus Acinetobacter was recorded in the egg stage when compared to other developmental stages, while the dominant fungal genus Wallemia was more abundant in the nymph and adult stages than in the egg stage. Additionally, the microbial composition differed between male and female adults, suggesting that the microbial communities in BPH were gender-dependent. Overall, our study enriches our knowledge on the microbial communities associated with BPH and will provide clues to develop potential biocontrol techniques against this rice pest.

Efficient and stable Sr3Eu2B4O12 red phosphor benefiting from low symmetry and distorted local environment.

The development of suitable red phosphors to obtain improved white color stands a good chance to serve in the new generation of white light-emitting diodes. Owing to multi-elements via doping and oxidation of reduced valence state of lanthanide or transition metal ions, most of the reported phosphors usually suffer from complex synthetic processes and unstable color of the lighting industry cycle. In this work, we present a new red emitting and stable Sr3Eu2B4O12 phosphor with regard to its special structure. It crystallizes as an orthorhombic cell, with Sr and Eu atoms co-occupying three different lattice sites in the space group of Pnma (no. 62). It is proposed that the long bond distance between activators minimizes the content quenching, while the high disorder of location restricts the thermal quenching. This phosphor emits bright red light with good color purity under UV excitation, with the luminescence intensity and quantum yield tunable via the fabrication temperature. Through a preliminary optimization of the synthesis process, the Sr3Eu2B4O12 phosphor prepared at 1250 °C has high quantum yields of about 94.7% and excellent thermal stability of 85.6% intensity retention at 150 °C relative to the initial value at room temperature. The calculated Judd-Ofelt intensity parameters (Ω2, Ω4) further clarified that the Eu3+ site in Sr3Eu2B4O12 had lower symmetry without an inversion center, and more distorted local environment and structural rigidity of the host, predicting excellent thermal stability. Finally, a warm pc-WLED device has been produced by mixing as-prepared Sr3Eu2B4O12 powders and commercial BaMgAl10O17:Eu2+ and (Sr, Ba)2SiO4:Eu2+ phosphors, which exhibits a high color rendering index (Ra = 83.4) along with a color temperature at around 4102 K. The present work indicates that the Sr3Eu2B4O12 phosphor is an efficient red component with excellent thermal stability for white-light production of near-UV-excited w-LEDs.