Antepenultimate residue at the C-terminus of NADPH oxidase RBOHD is critical for its function in the production of reactive oxygen species in Arabidopsis / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Production of reactive oxygen species (ROS) is a conserved immune response primarily mediated by NADPH oxidases (NOXs), also known in plants as respiratory burst oxidase homologs (RBOHs). Most microbe-associated molecular patterns (MAMPs) trigger a very fast and transient ROS burst in plants. However, recently, we found that lipopolysaccharides (LPS), a typical bacterial MAMP, triggered a biphasic ROS burst. In this study, we isolated mutants defective in LPS-triggered biphasic ROS burst (delt) in Arabidopsis, and cloned the DELT1 gene that was shown to encode RBOHD. In the delt1-2 allele, the antepenultimate residue, glutamic acid (E919), at the C-terminus of RBOHD was mutated to lysine (K). E919 is a highly conserved residue in NADPH oxidases, and a mutation of the corresponding residue E568 in human NOX2 has been reported to be one of the causes of chronic granulomatous disease. Consistently, we found that residue E919 was indispensable for RBOHD function in the MAMP-induced ROS burst and stomatal closure. It has been suggested that the mutation of this residue in other NADPH oxidases impairs the protein's stability and complex assembly. However, we found that the E919K mutation did not affect RBOHD protein abundance or the ability of protein association, suggesting that the residue E919 in RBOHD might have a regulatory mechanism different from that of other NOXs. Taken together, our results confirm that the antepenultimate residue E is critical for NADPH oxidases and provide a new insight into the regulatory mechanisms of RBOHD.

Antepenultimate residue at the C-terminus of NADPH oxidase RBOHD is critical for its function in the production of reactive oxygen species in Arabidopsis / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Production of reactive oxygen species (ROS) is a conserved immune response primarily mediated by NADPH oxidases (NOXs), also known in plants as respiratory burst oxidase homologs (RBOHs). Most microbe-associated molecular patterns (MAMPs) trigger a very fast and transient ROS burst in plants. However, recently, we found that lipopolysaccharides (LPS), a typical bacterial MAMP, triggered a biphasic ROS burst. In this study, we isolated mutants defective in LPS-triggered biphasic ROS burst (delt) in Arabidopsis, and cloned the DELT1 gene that was shown to encode RBOHD. In the delt1-2 allele, the antepenultimate residue, glutamic acid (E919), at the C-terminus of RBOHD was mutated to lysine (K). E919 is a highly conserved residue in NADPH oxidases, and a mutation of the corresponding residue E568 in human NOX2 has been reported to be one of the causes of chronic granulomatous disease. Consistently, we found that residue E919 was indispensable for RBOHD function in the MAMP-induced ROS burst and stomatal closure. It has been suggested that the mutation of this residue in other NADPH oxidases impairs the protein’s stability and complex assembly. However, we found that the E919K mutation did not affect RBOHD protein abundance or the ability of protein association, suggesting that the residue E919 in RBOHD might have a regulatory mechanism different from that of other NOXs. Taken together, our results confirm that the antepenultimate residue E is critical for NADPH oxidases and provide a new insight into the regulatory mechanisms of RBOHD.

Pathological comparison of lipopolysaccharide-and graphite particle-induced acute lung injury / 中国实验动物学报

Objective To compare the differences of lung pathological changes of acute lung injury in mice in-duced by lipopolysaccharide ( LPS) and graphite particles, and to explore the possible mechanisms of acute lung injury in-duced by fine particles of different origins.Methods 140 male specific-pathogen-free Kunming mice weighing 18-20 g were randomly divided into 7 experimental groups, in addition to the normal control group.The experimental groups were treated by intratracheal instillation of LPS solution or graphite powder suspension in different doses, respectively, to induce acute lung injury in the mice.The mortality of the mice was observed, and pathological changes of the lung tissues were ex-amined by light and transmission electron microscopy.Western blot was used to detect the protein expression of neutrophil elastase ( NE) in lung tissues , and real-time quantitative PCR was used to detect mRNA expression of monocyte chemotac-tic protein-1 ( MCP-1) in the lung tissue .Results Compared with the normal control group, some pathological changes were observed in the lung tissues of the groups L ( LPS) and G ( graphite) .There were numerous macrophages in the lung tissues in the group G mice, and exudate, mainly neutrophils, in the lung tissues of the group L.The NE protein expres-sion in the lung tissue was significantly higher than that of the normal control group ( P<0.05) , and there was also a sig-nificant difference between the groups L and G (P<0.05).The MCP-1 mRNA expression in lung tissues was higher in the control group (P<0.01), and there was also a significant difference between the groups L and G (P<0.01).Conclu-sions Diverse types of particulate matters induce different pathological changes in the lungs, therefore the mechanism may also be different in the inflammatory responses.It means that the lung injuries caused by fine particles of mixed composition may have complex mechanisms.

Protection of 1-hydroxy-2, 3, 5-trimethoxyxanthone on acute lung injury of mice induced by lipopolysaccharide / 中草药

Objective To investigate the protective effects of 1-hydroxy-2, 3, 5-trimethoxyxanthone (QGS) on acute lung injury of mice induced by ip lipopolysaccharide (LPS). Methods Mice were pretreated with QGS for 7 d. Murine models of acute lung injury were duplicated by injection of LPS 20 mg/kg intraperitoneally. In 12 h, the lung weight index was observed and the NO level in the bronchoalveolar lavage fluid (BALF) was measured with kits. The lung was also assessd for the expression of I-?B, inducible nitric oxide synthase (iNOS), and cyclooxygenase-Ⅱ (COX-2) using Western blotting analysis. Lung pathological changes were also observed by HE in each group. Results The lung weight index of injury lung in mice induced by LPS was decreased in 500 mg/kg QGS group (P