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Burkholderia plantarii is a causal agent of bacterial seedling blight of rice. This pathogen is of strong infectivity, reproductive capacity and adapt ability, and thus poses a serious threat to rice production. Hereby, the occurrence, damage and pathogenic mechanism of B.plantarii are introduced. Research progress of physiological traits and the regulation of pathogenicity controlled by bacterial quorum sensing (QS) in B.plantarii are also discussed. Moreover, from the point of view of microbial interaction in rhizosphere, the mechanisms of quorum quenching by interspecific signaling molecules against bacterial pathogens are summarized. According to the characteristics of the interspecies signaling molecules, their importance and application potential in development of novel bactericides are also previewed. [ABSTRACT FROM AUTHOR]

Abstract: The delivery of anticancer agents to solid tumors is problematic. Nanomolecular drug carriers represent an attractive alternative strategy for efficient anticancer drug delivery to tumor tissue, because they appear to target tumors and have limited toxicity in normal tissue. However, inadequate and heterogeneous distribution of nanocarriers in tumor tissue is a major impediment for their efficient use in clinical cancer therapy. In the present study, we examined the effect of tumor type on the intratumor accumulation and distribution of polyethylene glycol (PEG)-coated liposomes using in vivo mouse models of three cancer cell lines: colon adenocarcinoma (C26), Lewis lung carcinoma (LLC), and B16BL6 melanoma (B16BL6). The tumor growth inhibition and the apoptotic response of oxaliplatin (l-OHP) encapsulated in the PEG-coated liposomes were tumor type dependent and correlated with a tendency toward tumor accumulation and intratumor distribution of PEG-coated liposome, in contrast to in vitro cytotoxicity of l-OHP. A potent antitumor effect observed in both C26 and LLC tumor-bearing mice was attributed to the enhanced extravasation with subsequent preferential accumulation of PEG-coated liposomes through tumor vasculature with high permeability. Our results suggest that the permeability of tumor vasculature constitutes a potential impediment to tumor localization and thereby to the antitumor efficacy of PEG-coated liposomal anticancer drugs. [Copyright &y& Elsevier]

See also the Commentary on this article by Zhang et al., 242: 327–330. [ABSTRACT FROM AUTHOR]

Rice false smut is an important fungal disease at the rice heading stage, which causes severe loss to yield production and rice quality. Due to insufficient growth performance of Ustilaginoidea virens in vitro, screening and observation of effective fungicides in bioassay have been restricted. In this work, selection, combination and optimization of various carbon, nitrogen sources and coagulants have been carried out, an optimized culture system for U. virens growth was developed. The growth rate of U. virens in 5 representative types of commercial media was only from 0.7 to 2.3 mm/d, while the significant growth promotion effect on U. virens was observed in 77% of 18 types of compound media. Especially, maximum growth rate of 3.4 mm/d was observed in the peptone sucrose gellan gum (PSGG) medium. Interestingly, growth promotion effect of this medium was also observed on different strains of U. virens collected from rice grown in geographically diverse regions. Moreover, supplementation of 0.02% MgSO4 into the media solidified using gellan gum could enhance the solidification degree of the culture system, but did not affect the growth of U. virens. This indicated that peptone and sucrose were ideal nitrogen and carbon sources, respectively, in the PSGG medium, and gellan gum was a favorable coagulant. Our results would improve the growth rate of U. virens in vitro, and advance the understanding of underlying mechanism involved in the growth of U. virens, and also serve as an basis for the efficiency improvement of the bioassay system for U. virens. [ABSTRACT FROM AUTHOR]

[Display omitted] • The critical mechanisms underlying the microbiome assembly in the tea plants are revealed. • There is a trade-off between stochastic and deterministic processes in microbiome assembly in the tea plants. • Assembly processes were dominated by deterministic processes in bulk and rhizosphere soils. • The stochastic processes in roots and leaves was critically driven by amino acids for environmental selection. • The core taxa assembled in phyllosphere could attenuate the virulence of a prevalent foliar pathogen. Assembly and co-occurrence of the host co-evolved microbiota are essential ecological and evolutionary processes, which is not only crucial for managing individual plant fitness but also ecological function. However, understanding of the microbiome assembly and co-occurrence in higher plants is not well understood. The tea plant was shown to contribute the forest fitness due to the microbiome assembled in the phyllosphere; the landscape of microbiome assembly in the tea plants and its potential implication on phyllosphere homestasis still remains untangled. This study aimed to deciphering of the microbiome networks of the tea plants at a continental scale. It would provide fundamental insights into the factors driving the microbiome assembly, with an extended focus on the resilience towards the potential pathogen in the phyllosphere. We collected 225 samples from 45 locations spanning approximately 2000-km tea growing regions across China. By integration of high-throughput sequencing data, physicochemical properties profiling and bioinformatics analyses, we investigated continental scale microbiome assembly and co-occurrence in the tea plants. Synthetic assemblages, interaction assay and RT-qPCR were further implemented to analyze the microbial interaction indexed in phyllosphere. A trade-off between stochastic and deterministic processes in microbiomes community assembly was highlighted. Assembly processes were dominated by deterministic processes in bulk and rhizosphere soils, and followed by stochastic processes in roots and leaves with amino acids as critical drivers for environmental selection. Sphingobacteria and Proteobacteria ascended from soils to leaves to sustain a core leaf taxa. The core taxa formed a close association with a prevalent foliar pathogen in the co-occurrence network and significantly attenuated the expression of a set of essential virulence genes in pathogen. Our study unveils the mechanism underpinning microbiome assembly in the tea plants, and a potential implication of the microbiome-mediated resilience framework on the phyllosphere homeostasis. [ABSTRACT FROM AUTHOR]

A qualitative and quantitative method using UPLC-MS/MS was developed for the analysis of penoxsulam residues in rice paddy samples including rice plant, paddy water, soil and brown rice. The residue and dissipation of penoxsulam in the rice paddy were investigated for dietary risk assessment of residual penoxsulam in brown rice. Based on the analytical approach, the satisfied linearity was obtained in the concentration ranged from 0.005 mg/L to 0.5 mg/L with the limit of detection(LOD) from 0.001 mg/kg to 0.002 mg/kg and the limit of quantification(LOQ) from 0.003 mg/kg to 0.005 mg/kg. With the spiked concentrations of 0.005 to 0.5 mg/kg, the average recoveries varied from 89% to 106% with the relative standard deviation (RSD) from 2.8% to 8.5%. Those results indicated that this new method has favorable accuracy, precision and sensitivity, which meets the demand of pesticide residue analysis and is applicable for effective monitoring the penoxsulam residual in rice paddy field. The results of residue dynamics indicated that the half-lives of penoxsulam in rice plant, paddy soil and water were 1.5-3.3 d, 3.0-4.7 d, and 1.6-3.0 d, respectively. Hence, penoxsulam belongs to a class of readily-degradable herbicide in the rice paddy environment. After the application of 0.025% penoxsulam granules twice with the dosage at 37.5 g a.i./hm2 and 56.3 g a.i./hm2, respectively, the highest residues of penoxsulam in brown rice were lower than 0.005 mg/kg and the dietary risk was low in which the risk quotient was 2.22×10-4, which was obviously lower than risk threshold. Taken together, our data can be used as an important methodological and statistical basis for the further integrated evaluation of dietary risk and MRL formulation. [ABSTRACT FROM AUTHOR]

A method was developed for simultaneous determination of fluopyram and its metabolite residues in vegetables by gas chromatography-tandem mass spectrometry (GC-MS/MS). Samples were extracted with acetonitrile, and salted-out by magnesium sulfate and sodium chloride. After clean up with PSA, the analyte was subjected to determination using GC-MS/MS. The results showed that the average recoveries varied from 80% to 108% at the spiked concentrations of 0.01, 0.1 and 1 mg/kg, with the relative standard deviation (RSD) varied from 1.5% to 8.4%. The limits of detection (LOD, S/N = 3) varied from 2.17 μg/kg to 3.13 μg/kg for fluopyram in different vegetable samples, while the LOD of fluopyram metabolite varied from 1.22 μg/kg to 2.04 μg/kg. For both fluopyram and its metabolite, the limit of quantification (LOQ) (based on the recovery test) was 0.01 mg/kg. Hence, the method developed in this work is convenient, rapid, reliable, and, more importantly, applicable for qualitative and quantitative analyses of residues of fluopyram and its metabolite in the majority of vegetables. [ABSTRACT FROM AUTHOR]

Malignancy arising in fibrous dysplasia (FD) is rare. Approximately 100 cases have been reported so far, and osteosarcoma is the most common malignancy. We report a case of osteosarcoma in a 33-year-old Japanese man with monostotic FD of the right proximal femur from the age of 16 years. Histologically, relatively well-differentiated osteosarcoma was found in the FD lesion. Immunohistochemically, the FD was negative for p53 or MDM2, and the MIB-1 index was less than 1%, whereas the osteosarcoma was positive for both p53 and MDM2, and the MIB-1 index was up to 15%. The FD and osteosarcoma were negative for CDK4. Fluorescent in situ hybridization assay showed no amplification of the MDM2 gene, indicating that the osteosarcoma was a conventional osteosarcoma, not an intraosseous well-differentiated type. The original cell of malignancy in FD is unclear. Malignancy can be potentially derived from dysplastic cells in the area of the FD or cells in the adjacent normal tissues. GNAS gene mutation has recently been reported for fibrous dysplasia and the mutation is highly specific to fibrous dysplasia among fibro-osseous lesions including osteosarcoma. In this case, point mutations of GNAS were found in the FD and osteosarcoma but not in the adjacent normal tissues, suggesting that osteosarcoma was derived from the spindle cells of FD. This is the first report to clearly show that osteosarcoma is derived from the spindle cells in fibrous dysplasia (FD). [ABSTRACT FROM AUTHOR]

The auditory pressure thresholds of red sea bream were examined using cardiac response in the field by placing fish subjects far from the sound source to prevent particle motion. Pressure and particle motion thresholds were also obtained using the auditory brainstem response (ABR) technique. The thresholds at 100 and 200 Hz were significantly higher when measured using the cardiac response in the far field than those obtained in previously conducted experiments in experimental tub. However, thresholds obtained using ABR from 200 to 500 Hz were not remarkably lower, although significantly different (0.01 < P < 0.05), compared with those obtained using cardiac response in the far field. Furthermore, calculated particle velocity thresholds indicated that fish probably detected particle motion within the frequency range of 50–200 Hz, even in fish with a deactivated lateral line. Although the ABR method is widely applied in fish auditory study, hearing thresholds are apparently affected by particle motion. [ABSTRACT FROM AUTHOR]

The increasing input of fungicides has emerged as a global concern for agroecosystem stability and sustainability. Agroecosystem resilience has been linked to microbiome response, however, is not well understood. Focusing on a widespread triazole-class fungicide triadimefon in the paddy ecosystem, we characterized that the soils and sediments were dominant triadimefon reservoirs with the peak level at 195 μg kg−1 and 31.3 μg kg−1, respectively, but essential for the resilience of paddy ecosystem to triadimefon. In paddy simulation models, the half-life of triadimefon in soil-sediment was 8.4–28.9 days, while it was prolonged to 86.6–115.5 days after elimination of resident microbial community. Phospholipid fatty acid profiling and high-throughput sequencing showed that the distinctive bacterial community responses contributed to variable degradation of triadimefon in paddy soils and sediments. Sphingomonas and Xanthomonas were identified as positive responders of the keystone taxa in the responsive bacteriome, whereas Enterobacter were negative responders that declined over time. Synthetic assemblages combined with quantitative polymerase chain reaction further validated that Sphingomonas and Xanthomonas were involved in sustaining soil-sediment resilience to triadimefon contamination. Collectively, our results revealed that the shaping of soil and sediment bacteriomes was responsible for the resilience of the paddy agroecosystem to fungicide contamination. [Display omitted] • The resilience of the paddy ecosystem to triadimefon was dominantly conferred by the soils and sediments. • The resilience in paddy soils and sediments was associated with bacterial community. • Distinctive bacteriome responses to triadimefon were observed between paddy soils and sediments. • The keystone taxa of triadimefon-responsive bacteriome were characterized in paddy soils and sediments. [ABSTRACT FROM AUTHOR]