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161.
Thi Thuy Duong Michel Coste Agnès Feurtet-Mazel Dinh Kim Dang Caroline Gold Young Seuk Park Alain Boudou 《Hydrobiologia》2006,563(1):201-216
The effects of urban pollution from Hanoi city on the benthic diatom communities of the Nhue–Tolich river system were studied
during the 2003 dry season. Benthic diatoms were allowed to grow on glass slides suspended in the water flow for 4 weeks.
To reveal the relationship between water quality and diatom communities, Canonical correspondence analysis (CCA) was used
on data concerning relative abundances of diatom species and environmental variables. Two diatom indices, IPS and DAIpo, were
applied to evaluate water quality in the three rivers. A total of 291 diatom taxa were found in the Red, Nhue and Tolich Rivers.
These were mainly cosmopolitan taxa, with some tropical, subtropical and endemic taxa. The most abundant taxa at the Red site
were Aulacoseira granulata, Achnanthidium minutissimum, Encyonema minutum, Navicula recens and other halophilous taxa such as Nitzschia kurzii, Seminavis strigosa, Entomoneis paludosa, Bacillaria paradoxa. Diatom assemblages at the Tolich site consisted mainly of Nitzschia umbonata, Nitzschia palea and Eolimna minima. Diatom density ranged from 660 to 30,000 cells/cm2. Environmental variables and diatom assemblage composition at all sites were significantly correlated. Two diatom indices
gave similar results and indicate the Tolich River with the lowest values as a highly polluted site. 相似文献
162.
Two novel ion-pair complexes, [RBzIQl]+[Ni(mnt)2]− (mnt2− = maleonitriledithiolate, [RBzIQl]+ = 4-R-benzylisoquinolinium; R = H (1), Cl (2)) have been characterized structurally and magnetically. The anions and [BzIQl]+ cations of 1 form 1D column of alternating between cations and anions via π?π stacking interaction between Ni(mnt)2 plane and isoquinoline ring, and the Ni(mnt)2 anions between adjacent columns exist C?N, C?N, and N?N interaction. The anions and cations of 2 stack into well-segregated columns in the solid state; and the Ni(III) ions form a 1D zigzag chain in a Ni(mnt)2 column through intermolecular Ni?S, S?S, Ni?Ni or π?π interactions. The chain is uniform in 2 with the Ni?Ni distances of 3.784 Å. Magnetic susceptibility measurements for these complexes in the temperature range 1.8-300 K show that 1 exhibits antiferromagnetic coupling behavior, and 2 exhibits unusual magnetic phase transitions around 45 K. The overall magnetic behavior for 2 indicates the presence of antiferromagnetic interaction in the high-temperature phase (HT) and spin gap in the low-temperature phase (LT). 相似文献
163.
Allozyme analysis, microsatellite primer PCR (SSRP-PCR), and amplified fragment length polymorphism (AFLP) techniques were used to assess genetic diversity and population structure of the Chinese oriental migratory locust, Locusta migratoria manilensis. A total of 299 PCR markers (67 SSRPs and 232 AFLPs) were detected in eight populations, of which 98.7% were polymorphic markers. The proportion of polymorphic loci (95.5-98.8%) by SSRP+AFLP markers indicated no significant differences between populations, and all populations exhibited a similar level of variability; results of the allozyme analysis demonstrated that 19 loci gave rise to a lower level of polymorphism (55.6-66.7%). The genetic distances between the populations were relatively low. Shannon's index and Nei's gene diversity showed low differentiation among the populations. Allozyme analysis, however, reflected greater similarity and smaller differentiation between the populations than those shown by SSRP and AFLP markers. Neighbor-joining dendrograms derived from both the allozyme and SSRP+AFLP markers showed that the genetic distances among Chinese oriental migratory locust populations were not greatly influenced by geographic distance and breeding habitats. 相似文献
164.
Fatal outcome of human influenza A (H5N1) is associated with high viral load and hypercytokinemia 总被引:1,自引:0,他引:1
de Jong MD Simmons CP Thanh TT Hien VM Smith GJ Chau TN Hoang DM Chau NV Khanh TH Dong VC Qui PT Cam BV Ha do Q Guan Y Peiris JS Chinh NT Hien TT Farrar J 《Nature medicine》2006,12(10):1203-1207
Avian influenza A (H5N1) viruses cause severe disease in humans, but the basis for their virulence remains unclear. In vitro and animal studies indicate that high and disseminated viral replication is important for disease pathogenesis. Laboratory experiments suggest that virus-induced cytokine dysregulation may contribute to disease severity. To assess the relevance of these findings for human disease, we performed virological and immunological studies in 18 individuals with H5N1 and 8 individuals infected with human influenza virus subtypes. Influenza H5N1 infection in humans is characterized by high pharyngeal virus loads and frequent detection of viral RNA in rectum and blood. Viral RNA in blood was present only in fatal H5N1 cases and was associated with higher pharyngeal viral loads. We observed low peripheral blood T-lymphocyte counts and high chemokine and cytokine levels in H5N1-infected individuals, particularly in those who died, and these correlated with pharyngeal viral loads. Genetic characterization of H5N1 viruses revealed mutations in the viral polymerase complex associated with mammalian adaptation and virulence. Our observations indicate that high viral load, and the resulting intense inflammatory responses, are central to influenza H5N1 pathogenesis. The focus of clinical management should be on preventing this intense cytokine response, by early diagnosis and effective antiviral treatment. 相似文献
165.
166.
Sirtuin-independent effects of nicotinamide on lifespan extension from calorie restriction in yeast 总被引:3,自引:0,他引:3
Tsuchiya M Dang N Kerr EO Hu D Steffen KK Oakes JA Kennedy BK Kaeberlein M 《Aging cell》2006,5(6):505-514
Two models have been proposed for how calorie restriction (CR) enhances replicative longevity in yeast: (i) suppression of rDNA recombination through activation of the sirtuin protein deacetylase Sir2 or (ii) decreased activity of the nutrient-responsive kinases Sch9 and TOR. We report here that CR increases lifespan independently of all Sir2-family proteins in yeast. Furthermore, we demonstrate that nicotinamide, an inhibitor of Sir2-mediated deacetylation, interferes with lifespan extension from CR, but does so independent of Sir2, Hst1, Hst2, and Hst4. We also find that 5 mm nicotinamide, a concentration sufficient to inhibit other sirtuins, does not phenocopy deletion of HST3. Thus, we propose that lifespan extension by CR is independent of sirtuins and that nicotinamide has sirtuin-independent effects on lifespan extension by CR. 相似文献
167.
Emanuel PA Dang J Gebhardt JS Aldrich J Garber EA Kulaga H Stopa P Valdes JJ Dion-Schultz A 《Biosensors & bioelectronics》2000,14(10-11):751-759
Antibodies are critical reagents used in several biodetection platforms for the identification of biological agents. Recent advances in phage display technology allow isolation of high affinity recombinant antibody fragments (Fabs) that may bind unique epitopes of biological threat agents. The versatility of the selection process lends itself to efficient screening methodologies and can increase the number of antigen binding clones that can be isolated. Pilot scale biomanufacturing can then be used for the economical production of these immunoglobulin reagents in bacterial fermentation systems, and expression vectors with hexahistidine tags can be used to simplify downstream purification. One such Fab reagent directed against botulinum neurotoxin A/B has been shown to be sensitive in a variety of assay formats including surface plasmon resonance (SPR), flow cytometry, enzyme linked immunosorbent assay (ELISA), and hand-held immunochromatographic assay. Recombinant antibodies can provide another source of high quality detection reagents in our arsenal to identify or detect pathogens in environmental samples. 相似文献
168.
Physcomitrella patens is an extremely dehydration-tolerant moss. However, the molecular basis of its responses to loss of cellular water remains unclear. A comprehensive proteomic analysis of dehydration- and rehydration-responsive proteins has been conducted using quantitative two-dimensional difference in-gel electrophoresis (2D-DIGE), and traditional 2-D gel electrophoresis (2-DE) combined with MALDI TOF/TOF MS. Of the 216 differentially-expressed protein spots, 112 and 104 were dehydration- and rehydration-responsive proteins, respectively. The functional categories of the most differentially-expressed proteins were seed maturation, defence, protein synthesis and quality control, and energy production. Strikingly, most of the late embryogenesis abundant (LEA) proteins were expressed at a basal level under control conditions and their synthesis was strongly enhanced by dehydration, a pattern that was confirmed by RT-PCR. Actinoporins, phosphatidylethanolamine-binding protein, arabinogalactan protein, and phospholipase are the likely dominant players in the defence system. In addition, 24 proteins of unknown function were identified as novel dehydration- or rehydration-responsive proteins. Our data indicate that Physcomitrella adopts a rapid protein response mechanism to cope with dehydration in its leafy-shoot and basal expression levels of desiccation-tolerant proteins are rapidly upgraded at high levels under stress. This mechanism appears similar to that seen in angiosperm seeds. 相似文献
169.
Yamazaki H Naito M Ghani FI Dang NH Iwata S Morimoto C 《Biochemical and biophysical research communications》2012,419(3):529-536
Malignant mesothelioma (MM) is an asbestos-related malignancy characterized by rapid growth and poor prognosis. In our previous study, we have demonstrated that several cancer stem cell (CSC) markers correlated with CSC properties in MM cells. Among these markers, we focused on two: CD24, the common CSC marker, and CD26, the additional CSC marker. We further analyzed the CSC properties of CD24 and CD26-positve MM cells. We established RNAi-knockdown cells and found that these markers were significantly correlated with chemoresistance, proliferation, and invasion potentials in vitro. Interestingly, while Meso-1 cells expressed both CD24 and CD26, the presence of each of these two markers was correlated with different CSC property. In addition, downstream signaling of these markers was explored by microarray analysis, which revealed that their expressions were correlated with several cancer-related genes. Furthermore, phosphorylation of ERK by EGF stimulation was significantly affected by the expression of CD26, but not CD24. These results suggest that CD24 and CD26 differentially regulate the CSC potentials of MM and could be promising targets for CSC-oriented therapy. 相似文献
170.
Membrane active antitumor activity of NK-18, a mammalian NK-lysin-derived cationic antimicrobial peptide 总被引:1,自引:0,他引:1
As the increasing emergence of multi-drug resistant tumor cells, there is an urgent need for developing new chemotherapeutic agents. NK-lysin was a novel effector of cytotoxic T cells and natural killer (NK) cells and had broad antimicrobial activity. In this study, we developed a core region of NK-lysin termed NK-18, and studied its antitumor activity and possible action mode. Our results showed that NK-18 (with 18 amino acids) possesses potent antitumor activity against bladder and prostate cancer cells by disrupting the integrity of cell membrane, but has negligible hemolysis activity against mouse erythrocytes. In addition, CD spectra was employed to study its conformation in membrane mimicking environment. NK-18 takes a standard α-helical conformation in membrane mimicking environment, which could be accounted for its more potent antitumor activity compared with its low α-helical content homologous derivatives. These findings together with its shorter amino acid sequence and lower synthesis cost suggest that NK-18 could present an alternative therapeutic strategy to cancer chemotherapy and play a promising role in fighting the multi-drug resistant tumors. 相似文献