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81.
BJÖRN WISSEL RYAN N. COOPER PETER R. LEAVITT SAMANTHA V. PHAM 《Global Change Biology》2011,17(1):172-185
Endorheic lakes of the northern Great Plains encompass a wide range of environmental parameters (e.g., salinity, pH, DOC, Ca, nutrients, depth) that vary 1000‐fold among sites and through the past 2000 years due to variation in basin hydrology and evaporative forcing. However, while many environmental parameters are known to individually influence zooplankton diversity and taxonomic composition, relatively little is known of the hierarchical relationships among potential controls or of how regulatory mechanisms may change in response to climate variation on diverse scales. To address these issues, we surveyed 70 lakes within a 100 000 km2 prairie region to simulate the magnitude of environmental change expected to occur over 100–1000 years and to quantify the unique and interactive effects of diverse environmental parameters in regulating pelagic invertebrate community structure at that scale. Multivariate analyses showed that salinity was the principal correlate of changes in invertebrate composition among lakes, with a sequential loss of taxa between salinities of 4 and 50 g total dissolved solids L?1 until one to two species predominated in highly saline systems. In contrast, changes in the concentrations of Ca2+ and other mineral nutrients exerted secondary controls of invertebrate assemblages independent of salinity, whereas lake depth provided a tertiary regulatory mechanism structuring species composition. In contrast to these large‐scale hierarchical patterns, seasonal surveys (May, July, September) of a subset of 21 lakes in each of 2003–2005 revealed that annual meteorological variation had no measurable effect on pelagic invertebrates, despite large differences in temperature, precipitation, and evaporation arising from regional droughts. Together these findings show that pelagic invertebrate communities in saline lakes are resilient to interannual variability in climate, but suggest that lakes of the northern Great Plains may provide a sensitive model to forecast centennial effects of future climate change. 相似文献
82.
Increasing efforts are being made to develop more sensitive and faster molecular methodologies at the genomic and proteomic levels for the identification of protein markers after exposure to ionizing radiation (IR). However, few specific protein markers, especially organ-specific markers, have been identified. In this study, we analyzed altered protein expressions in various tissues, namely, brain, lung, spleen, and intestine, from 1 Gy-irradiated mice by employing 2-DE analysis. MALDI-TOF MS and peptide mapping identified 25 proteins that showed greater than twofold expressional changes. In order to confirm significant differences between control and IR-treated samples, ten identified proteins with available commercial antibodies were selected for immunoblotting. Of these, only five showed protein expression patterns that were similar to 2-DE data. These were heat shock protein 5 (HSP 5), HSP 90 kDa β, HSP 1, transaldolase 1 (TA1), and phosphoglycerate kinase 1 (PGK1). In particular, PGK1 was specifically upregulated in mouse intestine, and TA1 was specifically downregulated in brain by irradiation. TA1 expression was unaltered in other tissues. Based on these data, we suggest that TA1 and PGK1 can be considered as candidate tissue-specific protein markers of IR exposure. 相似文献
83.
Sheng XC Casarez A Cai R Clarke MO Chen X Cho A Delaney WE Doerffler E Ji M Mertzman M Pakdaman R Pyun HJ Rowe T Wu Q Xu J Kim CU 《Bioorganic & medicinal chemistry letters》2012,22(3):1394-1396
A potent and novel class of phosphinic acid derived product-like inhibitors of the HCV NS3/4A protease was discovered previously. Modification of the phosphinic acid and quinoline heterocycle led to GS-9256 with potent cell-based activity and favorable pharmacokinetic parameters. Based on these attributes, GS-9256 was advanced to human clinical trial as a treatment for chronic infection with genotype 1 HCV. 相似文献
84.
85.
Efficient Library Construction by In Vivo Recombination with a Telomere-Originated Autonomously Replicating Sequence of Hansenula polymorpha
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So-Young Kim Jung-Hoon Sohn Jung-Hoon Bae Yu-Ryang Pyun Michael O. Agaphonov Michael D. Ter-Avanesyan Eui-Sung Choi 《Applied microbiology》2003,69(8):4448-4454
A high frequency of transformation and an equal gene dosage between transformants are generally required for activity-based selection of mutants from a library obtained by directed evolution. An efficient library construction method was developed by using in vivo recombination in Hansenula polymorpha. Various linear sets of vectors and insert fragments were transformed and analyzed to optimize the in vivo recombination system. A telomere-originated autonomously replicating sequence (ARS) of H. polymorpha, reported as a recombination hot spot, facilitates in vivo recombination between the linear transforming DNA and chromosomes. In vivo recombination of two linear DNA fragments containing the telomeric ARS drastically increases the transforming frequency, up to 10-fold, compared to the frequency of circular plasmids. Direct integration of the one-end-recombined linear fragment into chromosomes produced transformants with single-copy gene integration, resulting in the same expression level for the reporter protein between transformants. This newly developed in vivo recombination system of H. polymorpha provides a suitable library for activity-based selection of mutants after directed evolution. 相似文献
86.
Kim CH Kang SU Pyun J Lee MH Hwang HS Lee H 《Apoptosis : an international journal on programmed cell death》2008,13(9):1184-1194
Cisplatin, a chemotherapeutic drug that is widely used to treat various cancers, promotes ototoxicity at higher doses. In
this study, the effect of epicatechin (EC) on cisplatin-induced hair cell death was investigated in a cochlear organ of Corti-derived
cell line, HEI-OC1, and in vivo in zebrafish. Cisplatin promoted apoptosis and altered mitochondrial membrane potential (MMP)
in HEI-OC1 cells. EC inhibited cisplatin-induced apoptosis and intracellular reactive oxygen species (ROS) generation. Labeling
of zebrafish lateral line hair cells by the fluorescent dye YO-PRO1 was lost upon exposure to cisplatin, and EC protected
against this cisplatin-induced loss of labeling in a dose-dependent manner. Scanning and transmission electron micrographs
showed that treatment with EC protected against cisplatin-induced loss of kinocilium and stereocilia in zebrafish neuromasts.
These results suggest that EC prevents cisplatin-induced ototoxicity by blocking ROS generation and by preventing changes
in MMP. 相似文献
87.
MG Mullender NA Blom M De Kleuver JM Fock WMGC Hitters AMC Horemans CJ Kalkman JEH Pruijs RR Timmer PJ Titarsolej NC Van Haasteren Tol-de MJ Van Jager AJ Van Vught BJ Van Royen 《Scoliosis》2008,3(1):1-14
Background
Children with neuromuscular disorders with a progressive muscle weakness such as Duchenne Muscular Dystrophy and Spinal Muscular Atrophy frequently develop a progressive scoliosis. A severe scoliosis compromises respiratory function and makes sitting more difficult. Spinal surgery is considered the primary treatment option for correcting severe scoliosis in neuromuscular disorders. Surgery in this population requires a multidisciplinary approach, careful planning, dedicated surgical procedures, and specialized after care.Methods
The guideline is based on scientific evidence and expert opinions. A multidisciplinary working group representing experts from all relevant specialties performed the research. A literature search was conducted to collect scientific evidence in answer to specific questions posed by the working group. Literature was classified according to the level of evidence.Results
For most aspects of the treatment scientific evidence is scarce and only low level cohort studies were found. Nevertheless, a high degree of consensus was reached about the management of patients with scoliosis in neuromuscular disorders. This was translated into a set of recommendations, which are now officially accepted as a general guideline in the Netherlands.Conclusion
In order to optimize the treatment for scoliosis in neuromuscular disorders a Dutch guideline has been composed. This evidence-based, multidisciplinary guideline addresses conservative treatment, the preoperative, perioperative, and postoperative care of scoliosis in neuromuscular disorders. 相似文献88.
Background
Obligate asexual reproduction is rare in the animal kingdom. Generally, asexuals are considered evolutionary dead ends that are unable to radiate. The phytophagous mite genus Bryobia contains a large number of asexual species. In this study, we investigate the origin and evolution of asexuality using samples from 111 populations in Europe, South Africa and the United States, belonging to eleven Bryobia species. We also examine intraspecific clonal diversity for one species, B. kissophila, by genotyping individuals from 61 different populations. Knowledge on the origin of asexuality and on clonal diversity can contribute to our understanding of the paradox of sex. 相似文献89.
Pyun HJ Fardis M Tario J Yang CY Ruckman J Henninger D Jin H Kim CU 《Bioorganic & medicinal chemistry letters》2004,14(1):91-94
Modification of fumagillin was conducted to develop MetAP-2 inhibitors with desirable pharmacological properties. Replacement of the C4 side chain by benzyloxime preserves the inhibitory activity against MetAP-2 enzyme. Fumagillin analogues containing the C4 benzyloxime moiety were found to be very sensitive to the nature of the C6 substituent on the inhibition activity of HUVEC proliferation. This lack of correlation between MetAP-2 and HUVEC activities might be due to the cellular metabolism of the compounds by epoxide hydrolase, which is present in the cell. Compound (E)-3d, containing ethylpiperazinyl carbamate at C6 position, exhibited antiangiogenic effects similar to TNP-470 on matrigel plug assay and rat corneal micropocket assay. 相似文献
90.
Kim SY Sohn JH Bae JH Pyun YR Agaphonov MO Ter-Avanesyan MD Choi ES 《Applied and environmental microbiology》2003,69(8):4448-4454
A high frequency of transformation and an equal gene dosage between transformants are generally required for activity-based selection of mutants from a library obtained by directed evolution. An efficient library construction method was developed by using in vivo recombination in Hansenula polymorpha. Various linear sets of vectors and insert fragments were transformed and analyzed to optimize the in vivo recombination system. A telomere-originated autonomously replicating sequence (ARS) of H. polymorpha, reported as a recombination hot spot, facilitates in vivo recombination between the linear transforming DNA and chromosomes. In vivo recombination of two linear DNA fragments containing the telomeric ARS drastically increases the transforming frequency, up to 10-fold, compared to the frequency of circular plasmids. Direct integration of the one-end-recombined linear fragment into chromosomes produced transformants with single-copy gene integration, resulting in the same expression level for the reporter protein between transformants. This newly developed in vivo recombination system of H. polymorpha provides a suitable library for activity-based selection of mutants after directed evolution. 相似文献