Synergistic deletion of RGS1 and COS1 may reduce the pathogenicity of Magnaporthe oryzae.

Rice blast, caused by Magnaporthe oryzae, is a serious threat to global rice production. In recent years, many pathogenicity genes of M. oryzae have been identified, although most of their functions remain unknown. In this study, we report the synergistic deletion of RGS1 and COS1 that may reduce the pathogenicity of M. oryzae. The investigation involved comparing ΔMorgs1, ΔMocos1, and ΔMorgs1/ΔMocos1 mutants. The ΔMorgs1/ΔMocos1 mutant showed a weak reduction in vegetative growth, and the colonies displayed fewer and smoother aerial hyphae. The ΔMorgs1/ΔMocos1 mutant exhibited delayed appressorium-like structure formation and 'low pathogenicity' on detached rice seedling leaves when compared with ΔMocos1. Moreover, the melanin content of the single and double mutants was remarkably lower than that of the WT type. Thus, our results indicate that the synergy between RGS1 and COS1 may be crucial in the pathogenicity of M. oryzae.

Research progress on chemical constituents and quality control methods of Succus Bambusae / 中国中药杂志

Through the investigation of a large number of both domestic and overseas literatures and related quality standards, chemical compositions, quality evaluation system and quality control methods of Succus Bambusae were systematic summarized in this study. There were abundant chemical constituents in Succus Bambusae, mainly including volatile ingredients, amino acids, flavonoids, trace elements and vitamins, with high medicinal and edible value. The quality control methods involved traditional morphological identification, spectroscopy, chromatography and other techniques. However, the current quality standards of Succus Bambusae are relatively low, lacking safety indicators, and cannot effectively ensure its quality, seriously affecting the safety and effectiveness of its clinical use. Therefore, it is particularly important to establish a set of highly sensitive and specific quality evaluation system for Succus Bambusae. In this paper, the current research status of the chemical compositions and quality standards of Succus Bambusae were reviewed, with the purpose of providing a basis for further improvement of its quality evaluation system.

Influence of oxidative/antioxidative biomarkers and inflammatory cytokines on rats after sub-acute orally administration of titanium dioxide nanoparticles / 北京大学学报(医学版)

OBJECTIVE@#To evaluate the sub-acute oral effect of titanium dioxide (TiO2) nanoparticles on the oxidation/antioxidation biomarkers and inflammatory cytokines in blood, liver, intestine, and colon in rats.@*METHODS@#Twenty four 4-week-old clean-grade Sprague Dawley (SD) rats were randomly devided into 4 groups by body weight (n=6, control, low, middle, and high), in which the rats were orally exposed to TiO2 nanoparticles at doses of 0, 2, 10 and 50 mg/kg body weight/day for 28 consecutive days separately. Food intake, body weight and abnormal behaviors during the experiment were recorded. The rats were euthanized on the 29th day. The blood was collected via abdominal aortic method and centrifuged to collect the serum. Tissues from liver, intestine and colon were collected and homogenated. Then enzyme-linked immunosorbent assay (ELISA) and microwell plate methods were used to detect oxidation/antioxidation biomarkers including superoxide dismutase (SOD), glutathione (GSH), glutathione peroxidase (GSH-Px), total mercapto (T-SH), glutathione disulfide (GSSG), malomdialdehvde (MDA) and inflammatory cytokines including interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) in the serum, liver, intestine and colon in the rats.@*RESULTS@#Compared with the control group, no significant differences in body weight, food intake and organ coefficients were observed in all the three groups after TiO2 gavage. No significant changes in GSH, GSH-Px, T-SH, and IL-6 were observed. Compared with the control group, significant increase of SOD activity in serum in high dose group, signi-ficant increase of GSSG concentration in intestine in middle and high dose group and significant increase of MDA concentration in liver in low and high dose group were observed. Compared with the control group, a significant increase of TNF-α in liver in middle and high dose group was observed.@*CONCLUSION@#TiO2 nanoparticle can increase antioxidant enzymes activities in blood, increase oxidative biomarkers in liver and intestine, increase inflammatory cytokines in liver in rats after a 28-day sub-acute orally administration. Among blood, liver, intestine, and colon, liver is most sensitive to the toxicity induced by TiO2 nanoparticles, followed by intestine, blood, and colon in sequence.

Early effects of low-level long-term occupational chromate exposure on workers'health / 北京大学学报(医学版)

OBJECTIVE@#To explore the effects of low-level long-term occupational exposure to chromate on the health of workers, and the potential biomarkers of early health effects in terms of lung function, immune toxicity and genetic damage.@*METHODS@#A total of 22 chromate contact workers and 44 non-chromate contact workers from an electroplating enterprise with long-term occupational environment monitoring in line with the national standards in Inner Mongolia were investigated. The questionnaire survey was conducted to collect the basic situation, the history of smoking, drinking, diseases and so on. The portable lung function instrument, inductively coupled plasma mass spectrometry and cytokinesis-blocked micronucleus test were performed to measure the chromate contact workers'lung function, whole blood Cr (WB-Cr) and micronuclei frequency (MNF) of peripheral blood lymphocytes respectively. The cytometric bead array was used to detect the levels of IL-1β, IL-6, IL-8, IL-10, IL-12P70 and TNFα in the serum among the two groups. The effects of chromate exposure on the above-mentioned indexes involved biological exposure, lung function, immune response and genetic damage, and their correlation were analyzed with different statistical methods.@*RESULTS@#(1) the average length of service for chromate contact workers was 31 years, and their concentration of WB-Cr was 1.11-4.19 μg/L. They were divided into high and low exposure groups according to the median of 1.72 μg/L. The WB-Cr in the high exposure group (2.17 μg/L) was higher than that in the low exposure group (1.58 μg/L) as well as the reference value of the healthy population (1.74 μg/L, P<0.05); (2) the lung function test showed 10 (45.45%) chromate exposure workers had single or multiple abnormal lung function indexes, among which large airway injury index PEF, and small airway injury indexes MVV and FEF25%-75% were all negatively correlated with WB-Cr (r=-0.53, P<0.05; r=-0.52, P<0.05; r=-0.44, P<0.05); (3) IL-1β, IL-6, IL-8 and TNFα in the serum of chromate contact workers were higher than those in the control group (P<0.05), and there was a positive correlation between TNFα and WB-Cr, and among these cytokines (P<0.05); (4) the average lymphocyte MNF in chromate contact workers was 1.341%, higher than the reference value of the general population (0.436%, P<0.01). Poisson regression analysis showed MNF in thehigh exposure group was higher than that in the low exposure group, OR (95%CI) =1.323 (1.049, 1.669); (5) multiple linear regression analysis showed that the lung function index FEF25%-75% decreased with the increase of TNFα (P<0.05), no significant correlation was found between other cytokines, MNF and lung function indexes.@*CONCLUSION@#Long-term low-level occupational exposure to chromate can cause the decline of lung function, immune inflammatory reaction and genetic damage in workers, in which local or systemic inflammatory response is associated with decreased lung function. Lung function indexes PEF, FEF25%-75% and MVV, serum cytokines IL-1β, IL-6, IL-8, and TNFα, and peripheral blood lymphocyte MNF may be used as early health effects biomarkers of chromate exposure.