70 research outputs found

    Quantitative assessment on the cloning efficiencies of lentiviral transfer vectors with a unique clone site

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    Lentiviral vectors (LVs) are powerful tools for transgene expression in vivo and in vitro. However, the construction of LVs is of low efficiency, due to the large sizes and lack of proper clone sites. Therefore, it is critical to develop efficient strategies for cloning LVs. Here, we reported a combinatorial strategy to efficiently construct LVs using EGFP, hPlk2 wild type (WT) and mutant genes as inserts. Firstly, site-directed mutagenesis (SDM) was performed to create BamH I site for the inserts; secondly, pWPI LV was dephosphorylated after BamH I digestion; finally, the amounts and ratios of the insert and vector DNA were optimized to increase monomeric ligation. Our results showed that the total percentage of positive clones was approximately 48%±7.6%. Using this method, almost all the vectors could be constructed through two or three minipreps. Therefore, our study provided an efficient method for constructing large-size vectors

    Transcriptome dynamics of a broad host-range cyanophage and its hosts

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    Cyanobacteria are highly abundant in the oceans and are constantly exposed to lytic viruses. The T4-like cyanomyoviruses are abundant in the marine environment and have broad host-ranges relative to other cyanophages. It is currently unknown whether broad host-range phages specifically tailor their infection program for each host, or employ the same program irrespective of the host infected. Also unknown is how different hosts respond to infection by the same phage. Here we used microarray and RNA-seq analyses to investigate the interaction between the Syn9 T4-like cyanophage and three phylogenetically, ecologically and genomically distinct marine Synechococcus strains: WH7803, WH8102 and WH8109. Strikingly, Syn9 led a nearly identical infection and transcriptional program in all three hosts. Different to previous assumptions for T4-like cyanophages, three temporally regulated gene expression classes were observed. Furthermore, a novel regulatory element controlled early-gene transcription, and host-like promoters drove middle gene transcription, different to the regulatory paradigm for T4. Similar results were found for the P-TIM40 phage during infection of Prochlorococcus NATL2A. Moreover, genomic and metagenomic analyses indicate that these regulatory elements are abundant and conserved among T4-like cyanophages. In contrast to the near-identical transcriptional program employed by Syn9, host responses to infection involved host-specific genes primarily located in hypervariable genomic islands, substantiating islands as a major axis of phage-cyanobacteria interactions. Our findings suggest that the ability of broad host-range phages to infect multiple hosts is more likely dependent on the effectiveness of host defense strategies than on differential tailoring of the infection process by the phage

    Combined intravenous methotrexate and cyclophosphamide for refractory childhood lupus nephritis

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    Methods: Five children were treated with nine monthly doses of IV CYTX (750–1000 mg/m(2)/month) and IV MTX (50–300 mg/m(2)/month) given on the same day. Their clinical and laboratory measurements were collected every other week throughout the nine months. Results: All children improved dramatically. SLEDAI scores decreased from an average of 13.8 to 4.4, mean (SD) serum creatinine level fell from 100 (60) to 80 (40) µmol/l, and serum albumin rose from 28 (11) g/l to 41 (6) g/l, while the mean (SD) C3 level increased from 0.5 (0.1) g/l to 0.9 (0.4) g/l. Clinical improvement persisted after 4 years' follow up despite discontinuing MTX and CYTX after 9 months. The average daily dose of corticosteroids has been reduced from 27.6 mg/day at the start of treatment to 12.5 mg/day at follow up. Conclusion: Combined IV MTX and IV CYTX treatment effectively controls recurrent or refractory lupus nephritis in children with significant disease activity after treatment with IV CYTX alone

    A new methyl mark on messengers

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    Impact of HLA-B27 and Disease Status on the Gut Microbiome of the Offspring of Ankylosing Spondylitis Patients

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    Multiple studies have shown the microbiota to be abnormal in patients with spondyloarthri-tis (SpA). The purpose of this study was to explore the genetic contributions of these microbiota abnormalities. We analyzed the impact of HLA-B27 on the microbiota of children at risk for SpA and compared the microbiota of HLA-B27+ pediatric offspring of ankylosing spondylitis (AS) patients with that of HLA-B27+ children with SpA. Human DNA was obtained from the offspring for determination of HLA-B27 status and polygenic risk score (PRS). Fecal specimens were collected from both groups for sequencing of the V4 region of the 16S ribosomal RNA gene. Among the offspring of AS patients, there was slight clustering by HLA-B27 status. After adjusting for multiple comparisons, five operational taxonomic units (OTUs) representing three unique taxa distinguished the HLA-B27+ from negative children: Blautia and Coprococcus were lower in the HLA-B27+ offspring, while Faecalibacterium prausnitzii was higher. HLA-B27+ offspring without arthritis were compared to children with treatment-naïve HLA-B27+ SpA. After adjustments, clustering by diagnosis was present. A total of 21 OTUs were significantly associated with diagnosis state, including Bacteroides (higher in SpA patients) and F. prausnitzii (higher in controls). Thus, our data confirmed associations with B fragilis and F prausnitzii with juvenile SpA, and also suggest that the mechanism by which HLA-B27 is associated with SpA may not involve alterations of the microbiota.</p
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