摘要:
A simple and direct synthesis of 2-aminoimidazoles from vinyl azides and cyanamide was developed. An attractive feature of this protocol is that the desired products are generated in a highly efficient and eco-friendly manner without the use of a catalyst. A plausible mechanism has been proposed. (C) 2014 Elsevier Ltd. All rights reserved.
摘要:
The incidence of non-tuberculous mycobacteria (NTM)-related death has increased globally recently. To obtain information of the species and characterization of pathogens involved in NTM pulmonary infection in Southern-central China, we identified 160 non-tuberculous infection cases from 3995 acid-fast bacilli (AFB)-positive tuberculous suspects. We then randomly selected 101 non-tuberculous patients, isolated bacteria from their sputa and genotyped the pathogens using the 16S rRNA gene and 16S-23S rRNA internal transcribed spacer sequences. M. intracellulare (32.67%, 33/101), M. abscessus (32.67%, 33/101) and M. fortuitum (7.92%, 8/101) are identified in these isolates. Surprisingly, non-mycobacteria including Gordonia (8.91%, 9/101), Nocardia (5.94%, 6/101) and Tsukamurella (0.99%, 1/101) are also discovered, and the case of Tsukamurella pulmonis infection is first discovered in Southern-central China. Moreover, species of M. mucogenicum group, M. chubuense, M. kansasii, M. gastri, M. avium, M. porcinum and M. smegmatis are identified. In addition, nine immune compromised cases (8.91%, 9/101), including type two diabetes mellitus and HIV/AIDS are found to be infected with non-tuberculous bacteria. This study revealed the distribution and characteristics of non-tuberculous AFB pathogen infection occurred in Southern-central China, and suggested that physicians should be alert of the emerging of NTM and non-mycobacteria infection in AFB positive cases and take caution when choosing chemotherapy for tuberculosis-like pulmonary infections. Generally, this study may help with the development of new strategy for the diagnosis and treatment of mycobacterial infection.
摘要:
Diethylhexyl phthalate (DEHP) is an estrogen-like compound widely used as a plasticizer in commercial products and is present in medical devices, and common household items. It is considered an endocrine disruptor since studies on experimental animals clearly show that exposure to DEHP can alter epigenetics of germ cells. This study was designed to assess the effects of DEHP on DNA methylation of imprinting genes in germ cells from fetal and adult mouse. Pregnant mice were treated with DEHP at doses of 0 and 40 mu g DEHP/kg body weight/day from 0.5 to 18.5 day post coitum. The data revealed DEHP exposure significantly reduced the percentage of methylated CpG sites in Igf2r and Peg3 differentially methylated regions (DMRs) in primordial germ cells from female and male fetal mouse, particularly, in the oocytes of 21 dpp mice (F1), which were produced by the pregnant micetreated with DEHP. More surprisingly, the modification of the DNA methylation of imprinted genes in F1 mouse oocytes was heritable to F2 offspring which exhibit lower percentages of methylated CpG sites in imprinted genes DMRs. In conclusion, DEHP exposure can affect the DNA methylation of imprinting genes not only in fetal mouse germ cells and growing oocytes, but also in offspring's oocytes.
作者机构:
[Liu, Jianfang; Wang, Ding; Gu, Kali; Zhao, Yuan] Wuhan Res Inst Mat Protect, Wuhan 430030, Hubei, Peoples R China.;[Liu, Jianfang] Wuhan Polytech Univ, Dept Biol & Pharmaceut Engn, Wuhan 430023, Hubei, Peoples R China.
通讯机构:
[Liu, Jianfang] W;Wuhan Res Inst Mat Protect, Wuhan 430030, Hubei, Peoples R China.
关键词:
Hydraulic Fluid;Lubricant Physical and Chemical Analysis;Lubricant Recycling;Lubrication Performance
摘要:
Used lubricating oil contains more than 90% of good base oil and available additives, providing the potential of energy conservation, environmental protection, and economy, though it loses its useful performance because of contamination by impurities, oxidation, and degradation of additives. Many countries around the world have focused on reclamation and re-refining methods to treat and reuse waste lubricating oils for many years. But the regeneration rate of waste oils is very low in China, less than 20% of the lubricant consumption. Few studies on the performance, especially lubrication properties of recycled lubricating oils, have been considered. In this article, based on differences between used and fresh oils, used oils were reclaimed and replenished with additives (henceforth refortified oils). The physical and chemical properties, including viscosity, total acid number, moisture content, copper corrosion, and water separability from petroleum oil and synthetic fluid as well as the lubrication characteristics of three kinds of refortified hydraulic oils were investigated. The lubrication performance was evaluated using a four-ball tribotester and a Universal Micro-Tribotester (UMT) reciprocating tester. Moreover, the worn surfaces were analyzed using confocal scanning optical microscopy (CSOM), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS), and Raman spectroscopy. The results showed that refortified oils provided good physical and chemical properties, close to those of fresh oils, and produced better tribological characteristics than used and even fresh oils. There were compositional differences between the films of fresh, used, and refortified oils.
摘要:
Cellulolytic bacteria in forest soil provide carbon sources to improve the soil fertility and sustain the nutrient balance of the forest ecological system through the decomposition of cellulosic remains. These bacteria can also be utilized for the biological conversion of biomass into renewable biofuels. In this study, the community compositions and activities of cellulolytic bacteria in the soils of forests planted with broad-leaved deciduous (Chang Qing Garden, CQG) and broad-leaved evergreen (Forest Park, FP) trees in Wuhan, China were resolved through restriction fragment length polymorphism (RFLP) and sequencing analysis of the 16S rRNA gene. All of the isolates exhibited 35 RFLP fingerprint patterns and were clustered into six groups at a similarity level of 50 %. The phylogeny analysis based on the 16S rRNA gene sequence revealed that these RFLP groups could be clustered into three phylogenetic groups and further divided into six subgroups at a higher resolution. Group I consists of isolates from Bacillus cereus, Bacillus subtilis complex (I-A) and from Paenibacillus amylolyticus-related complex (I-B) and exhibited the highest cellulase activity among all of the cellulolytic bacteria isolates. Cluster II consists of isolates belonging to Microbacterium testaceum (II-A), Chryseobacterium indoltheticum (II-B), and Flavobacterium pectinovorum and the related complex (II-C). Cluster III consists of isolates belonging to Pseudomonas putida-related species. The community shift with respect to the plant species and the soil properties was evidenced by the phylogenetic composition of the communities. Groups I-A and I-B, which account for 36.0 % of the cellulolytic communities in the CQG site, are the dominant groups (88.4 %) in the FP site. Alternatively, the ratio of the bacteria belonging to group III (P. putida-related isolates) shifted from 28.0 % in CQG to 4.0 % in FP. The soil nutrient analysis revealed that the CQG site planted with deciduous broad-leaved trees has a richer organic nutrient (total organic carbon and total nitrogen) than the FP site planted with evergreen broad-leaved trees. Against this background, the population density and the diversity of cellulolytic bacteria in the CQG site are clearly higher than those in the FP site, and the latter was dominated with high-cellulase-activity Bacillus- and Paenibacillus-related bacteria. The canonical correspondence analysis further indicated that the distribution of these groups is correlated with the FP site, whereas groups II and III are correlated with the organic nutrient-rich CQG site.
摘要:
AIM: To study the chemical constituents of the rhizomes of Alpinia officinarum Hance. METHOD: Compounds were isolated by repeated column chromatography, and their structures were elucidated on the basis of spectral analysis. The cytotoxic activities of these compounds were evaluated with the T98G and B16F10 cell lines by the MTT assay. RESULTS: A dimeric diarylheptanoid, named alpinin B (1), along with three known diarylheptanoids were obtained, and their structures were identified as alpinin B (1), 1, 7-diphenyl-3,5-heptanedione (2), (4E)-1, 7-diphenylhept-4-en-3-one (3) and (4E)-7- (4-hydroxyphenyl)-1-phenylhept-4-en-3-one (4). CONCLUSION: Compound 1 is a new dimeric diarylheptanoid. The biosynthetic pathway of 1 was speculated to originate from a Michael reaction between compounds 2 and 3. Compound 3 showed cytotoxicity against the human glioblastoma T98G cell line with IC_(50) of 27 μmol?L~(-1).
摘要:
We previously demonstrated that the effects of diethylhexyl phthalate (DEHP) alter reproduction function on male mice. Immature male mice were treated daily with DEHP from postnatal day 7-21, 7-35, 7-49, in a dose-dependent manner. As results, both the quality and quantity of spermatozoa were decreased in 60-day-old mice. The results by RT-PCR analysis indicated that DDx3Y, Usp9Y, RBM, E1F1AY, EGF, FSHR and EGFR genes were down-regulated, and LHR, Cyp17a1 and Cyp19a1 were down-regulated in response to DEHP. These genes were selected based on their markedly increased or decreased expression levels. However, DEHP had no effect on the meiotic process and recombination levels in male mouse germ cells. Treatment with DEHP induced histopathological changes in the testes. Taken together, these results provide a new insight into the molecular mechanisms underlying the detrimental impacts of DEHP in humans and wildlife.
摘要:
Listeria monocytogenes is a foodborne bacterial pathogen and the causative agent of an infectious disease, listeriosis. L. monocytogenes is ubiquitous in nature and has the ability to persist in food processing environments for extended periods of time by forming biofilms and resisting industrial sanitization. Human listeriosis outbreaks are commonly linked to contaminated dairy products, ready-to-eat meats, and in recent years, fresh produce such as lettuce and cantaloupes. We identified a putative Crp/Fnr family transcription factor Lmo0753 that is highly specific to human-associated genetic lineages of L. monocytogenes. Lmo0753 possesses two conserved functional domains similar to the major virulence regulator PrfA in L. monocytogenes. To determine if Lmo0753 is involved in environmental persistence-related mechanisms, we compared lmo0753 deletion mutants with respective wild type and complementation mutants of two fully sequenced L. monocytogenes genetic lineage II strains 10403S and EGDe for the relative ability of growth under different nutrient availability and temperatures, soil survival, biofilm productivity and attachment to select fresh produce surfaces including romaine lettuce leaves and cantaloupe rinds. Our results collectively suggested that Lmo0753 plays an important role in L. monocytogenes biofilm production and attachment to fresh produce, which may contribute to the environmental persistence and recent emergence of this pathogen in human listeriosis outbreaks linked to fresh produce.
作者机构:
[Gao TuLing; Zhao Gong; Chen Cheng; He XinYi; Deng ZiXin] Shanghai Jiao Tong Univ, State Key Lab Microbial Metab, Shanghai 200030, Peoples R China.;[Gao TuLing; Zhao Gong; Chen Cheng; He XinYi; Deng ZiXin] Shanghai Jiao Tong Univ, Sch Life Sci & Biotechnol, Shanghai 200030, Peoples R China.;[Gao TuLing; Hu ShenCai] Wuhan Polytech Univ, Sch Biol & Pharmaceut Engn, Wuhan 430023, Peoples R China.;[Xu, H. Howard] Calif State Univ Los Angeles, Dept Biol Sci, Los Angeles, CA 90032 USA.
通讯机构:
[He XinYi] S;Shanghai Jiao Tong Univ, State Key Lab Microbial Metab, Shanghai 200030, Peoples R China.
摘要:
Lipopolysaccharide (LPS) is a known activator of mononuclear phagocytes. LPS activates the pro-inflammatory gene expression and induces the release of mediators/cytokines by TLR4-NF-kappa B signaling pathway. The purpose of this study was to investigate the effects of acetaminophen (AAP) and N-acetylcysteine (NAC), individually as well as in combination on LPS-induced cytokines production and NF-kappa B activation in piglets. AAP (0.125-1.0 mM) and NAC (0.0625-1.0 mM) down-regulate the expression of cytokines and inhibit NF-kappa B p65 protein transfer from the cytoplasm to the nucleus in vitro. NAC enhances the inhibition action of AAP on cytokines expression in vitro. IL-6 in piglet plasma of the AAP group (mixed feed concentration of 600 mg/kg) was significantly reduced (P<0.05) at3 h after LPS-challenge as compared with the LPS control group. IL-10 also significantly reduced (P<0.05) at 24 h after LPS injection. The levels of inflammatory cytokines (TNF-alpha, IL-1p, IL-6, and IL10) in piglet plasma of the NAC group (mixed feeding concentration of 1200 mg/kg) were significantly lower at 3 h after LPS stimulation (P<0.05). IL-10 was significantly decreased in the NAC group at 24 h after LPS stimulation (P<0.05). AAP or NAC treated alone could reduce the NF-kappa B p65 concentration ratio. The levels of cytokines (TNF-alpha, IL-1 p, IL-6, and IL-10) in the group with piglet plasma of AAP (mixed feed concentration of 600 mg/kg) plus NAC (mixed feeding concentration of 1200 mg/kg) group were significantly lower (P<0.05) at 3 h after LPS activation. The level of IL-10 in the group with AAP plus NAC was significantly lower (P<0.05) at 24h after LPS stimulation, while the rest of the inflammatory cytokines were returned to the original levels. The NF-kappa B p65 concentration ratio had significantly reduced (P<0.05) when AAP and NAC were used in combination. In summary, NAC could enhance the anti-inflammatory effects of AAP both in vitro and in vivo. (C) 2013 Elsevier B.V. All rights reserved.