166 research outputs found
Genome-Wide Transcriptional Profiling of the Response of Staphylococcus aureus to Cryptotanshinone
Staphylococcus aureus (S. aureus) strains with multiple antibiotic resistances are increasingly widespread, and new agents are required for the treatment of S. aureus. Cryptotanshinone (CT), a major tanshinone of medicinal plant Salvia miltiorrhiza Bunge, demonstrated effective in vitro antibacterial activity against all 21 S. aureus strains tested in this experiment. Affymetrix GeneChips were utilized to determine the global transcriptional response of S. aureus ATCC 25923 to treatment with subinhibitory concentrations of CT. Transcriptome profiling indicated that the antibacterial action of CT may be associated with its action as active oxygen radical generator; S. aureus undergoes an oxygen-limiting state upon exposure to CT
A novel HIV-1-encoded microRNA enhances its viral replication by targeting the TATA box region
BACKGROUND: A lot of microRNAs (miRNAs) derived from viral genomes have been identified. Many of them play various important roles in virus replication and virus-host interaction. Cellular miRNAs have been shown to participate in the regulation of HIV-1 viral replication, while the role of viral-encoded miRNAs in this process is largely unknown. RESULTS: In this report, through a strategy combining computational prediction and deep sequencing, we identified a novel HIV-1-encoded miRNA, miR-H3. MiR-H3 locates in the mRNA region encoding the active center of reverse transcriptase (RT) and exhibits high sequence conservation among different subtypes of HIV-1 viruses. Overexpression of miR-H3 increases viral production and the mutations in miR-H3 sequence significantly impair the viral replication of wildtype HIV-1 viruses, suggesting that it is a replication-enhancing miRNA. MiR-H3 upregulates HIV-1 RNA transcription and protein expression. A serial deletion assay suggests that miR-H3 targets HIV-1 5β² LTR and upregulates the promoter activity. It interacts with the TATA box in HIV-1 5β² LTR and sequence-specifically activates the viral transcription. In addition, chemically-synthesized small RNAs targeting HIV-1 TATA box activate HIV-1 production from resting CD4(+) T cells isolated from HIV-1-infected patients on suppressive highly active antiretroviral therapy (HAART). CONCLUSIONS: We have identified a novel HIV-1-encoded miRNA which specifically enhances viral production and provide a specific method to activate HIV-1 latency
Similar operation template attack on RSA-CRT as a case study
A template attack, the most powerful side-channel attack methods, usually first builds the leakage profiles from a controlled profiling device, and then uses these profiles to recover the secret of the target device. It is based on the fact that the profiling device shares similar leakage characteristics with the target device. In this study, we focus on the similar operations in a single device and propose a new variant of the template attack, called the similar operation template attack (SOTA). SOTA builds the models on public variables (e.g., input/output) and recovers the values of the secret variables that leak similar to the public variables. SOTAβs advantage is that it can avoid the requirement of an additional profiling device. In this study, the proposed SOTA method is applied to a straightforward RSA-CRT implementation. Because the leakage is (almost) the same in similar operations, we reduce the security of RSA-CRT to a hidden multiplier problem (HMP) over GF(q), which can be solved byte-wise using our proposed heuristic algorithm. The effectiveness of our proposed method is verified as an entire prime recovery procedure in a practical leakage scenario
YeastWeb: a workset-centric web resource for gene family analysis in yeast
<p>Abstract</p> <p>Background</p> <p>Currently, a number of yeast genomes with different physiological features have been sequenced and annotated, which provides invaluable information to investigate yeast genetics, evolutionary mechanism, structure and function of gene families.</p> <p>Description</p> <p>YeastWeb is a novel database created to provide access to gene families derived from the available yeast genomes by assigning the genes into putative families. It has many useful features that complement existing databases, such as SGD, CYGD and GΓ©nolevures: 1) Detailed computational annotation was conducted with each entry with InterProScan, EMBOSS and functional/pathway databases, such as GO, COG and KEGG; 2) A well established user-friendly environment was created to allow users to retrieve the annotated genes and gene families using functional classification browser, keyword search or similarity-based search; 3) Workset offers users many powerful functions to manage the retrieved data efficiently, associate the individual items easily and save the intermediate results conveniently; 4) A series of comparative genomics and molecular evolution analysis tools are neatly implemented to allow users to view multiple sequence alignments and phylogenetic tree of gene families. At present, YeastWeb holds the gene families clustered from various MCL inflation values from a total of 13 available yeast genomes.</p> <p>Conclusions</p> <p>Given the great interest in yeast research, YeastWeb has the potential to become a useful resource for the scientific community of yeast biologists and related researchers investigating the evolutionary relationship of yeast gene families. YeastWeb is available at <url>http://centre.bioinformatics.zj.cn/Yeast/</url>.</p
p38 Mitogen-activated Protein Kinase (MAPK) Promotes Cholesterol Ester Accumulation in Macrophages through Inhibition of Macroautophagy
p38 MAPK has been strongly implicated in the development of atherosclerosis, but its role in cholesterol ester accumulation in macrophages and formation of foam cells, an early step in the development of atherosclerosis, has not been investigated. We addressed this issue and made some brand new observations. First, elevated intracellular cholesterol level induced by the exposure to LDL-activated p38 MAPK and activation of p38 MAPK with anisomycin increased the ratio of cholesterol esters over free cholesterol, whereas inhibition of p38 MAPK with SB203580 or siRNA reduced the LDL loading-induced intracellular accumulation of free cholesterol and cholesterol esters in macrophages. Second, exposure to LDL cholesterol inhibited autophagy in macrophages, and inhibition of autophagy with 3-methyladenine increased intracellular accumulation of cholesterol (free cholesterol and cholesterol esters), whereas activation of autophagy with rapamycin decreased intracellular accumulation of free cholesterol and cholesterol esters induced by the exposure to LDL cholesterol. Third, LDL cholesterol loading-induced inhibition of autophagy was prevented by blockade of p38 MAPK with SB203580 or siRNA. Neutral cholesterol ester hydrolase was co-localized with autophagosomes. Finally, LDL cholesterol loading and p38 activation suppressed expression of the key autophagy gene, ulk1, in macrophages. Together, our results provide brand new insight about cholesterol ester accumulation in macrophages and foam cell formation
Systematic review of the perioperative immunotherapy in patients with non-small cell lung cancer: evidence mapping and synthesis
ObjectivesThis study aimed to use evidence mapping to provide an overview of immune checkpoint inhibitors (ICIs) as perioperative treatments for non-small cell lung cancer (NSCLC) and to identify areas of this field where future research is most urgently needed.MethodsMultiple databases (PubMed, EMBASE, Cochrane Library, and Web of Science) were searched to identify clinical trials published up to November 2021 that examined the effect of perioperative ICIs for perioperative treatment of NSCLC. Study design, sample size, patient characteristics, therapeutic regimens, clinical stages, short-term and long-term therapeutic outcomes, surgery associated parameters, and therapeutic safety were examined.ResultsWe included 66 trials (3564 patients) and used evidence mapping to characterize the available data. For surgery associated outcomes, sixty-two studies (2480 patients) provided complete information regarding the use of surgery after neoadjuvant immunotherapy and data on R0 resection were available in 42 studies (1680 patients); for short-term clinical outcomes, 57 studies (1842 patients) evaluated pathologic complete response (pCR) after neoadjuvant immunotherapy and most of included studies achieved pCR in the range of 30 to 40%; for long-term clinical outcomes, 15 studies (1932 patients) reported DFS, with a median range of 17.9-53.6 months; and only a few studies reported the safety profiles of perioperative immunotherapies.ConclusionOur evidence mapping systematically summarized the results of all clinical trials and studies that examined ICIs as perioperative treatments for NSCLC. The results indicated more studies that evaluate long-term patient outcomes are needed to provide a stronger foundation for the use of these treatments
Transcriptional and Functional Analysis of the Effects of Magnolol: Inhibition of Autolysis and Biofilms in Staphylococcus aureus
BACKGROUND: The targeting of Staphylococcus aureus biofilm structures are now gaining interest as an alternative strategy for developing new types of antimicrobial agents. Magnolol (MOL) shows inhibitory activity against S. aureus biofilms and Triton X-100-induced autolysis in vitro, although there are no data regarding the molecular mechanisms of MOL action in bacteria. METHODOLOGY/PRINCIPAL FINDINGS: The molecular basis of the markedly reduced autolytic phenotype and biofilm inhibition triggered by MOL were explored using transcriptomic analysis, and the transcription of important genes were verified by real-time RT-PCR. The inhibition of autolysis by MOL was evaluated using quantitative bacteriolytic assays and zymographic analysis, and antibiofilm activity assays and confocal laser scanning microscopy were used to elucidate the inhibition of biofilm formation caused by MOL in 20 clinical isolates or standard strains. The reduction in cidA, atl, sle1, and lytN transcript levels following MOL treatment was consistent with the induced expression of their autolytic repressors lrgA, lrgB, arlR, and sarA. MOL generally inhibited or reversed the expression of most of the genes involved in biofilm production. The growth of S. aureus strain ATCC 25923 in the presence of MOL dose-dependently led to decreases in Triton X-100-induced autolysis, extracellular murein hydrolase activity, and the amount of extracellular DNA (eDNA). MOL may impede biofilm formation by reducing the expression of cidA, a murein hydrolase regulator, to inhibit autolysis and eDNA release, or MOL may directly repress biofilm formation. CONCLUSIONS/SIGNIFICANCE: MOL shows in vitro antimicrobial activity against clinical and standard S. aureus strains grown in planktonic and biofilm cultures, suggesting that the structure of MOL may potentially be used as a basis for the development of drugs targeting biofilms
A Small Amount of Dietary Carbohydrate Can Promote the HFD-Induced Insulin Resistance to a Maximal Level
Both dietary fat and carbohydrates (Carbs) may play important roles in the development of insulin resistance. The main goal of this study was to further define the roles for fat and dietary carbs in insulin resistance. C57BL/6 mice were fed normal chow diet (CD) or HFD containing 0.1β25.5% carbs for 5 weeks, followed by evaluations of calorie consumption, body weight and fat gains, insulin sensitivity, intratissue insulin signaling, ectopic fat, and oxidative stress in liver and skeletal muscle. The role of hepatic gluconeogenesis in the HFD-induced insulin resistance was determined in mice. The role of fat in insulin resistance was also examined in cultured cells. HFD with little carbs (0.1%) induced severe insulin resistance. Addition of 5% carbs to HFD dramatically elevated insulin resistance and 10% carbs in HFD was sufficient to induce a maximal level of insulin resistance. HFD with little carbs induced ectopic fat accumulation and oxidative stress in liver and skeletal muscle and addition of carbs to HFD dramatically enhanced ectopic fat and oxidative stress. HFD increased hepatic expression of key gluconeogenic genes and the increase was most dramatic by HFD with little carbs, and inhibition of hepatic gluconeogenesis prevented the HFD-induced insulin resistance. In cultured cells, development of insulin resistance induced by a pathological level of insulin was prevented in the absence of fat. Together, fat is essential for development of insulin resistance and dietary carb is not necessary for HFD-induced insulin resistance due to the presence of hepatic gluconeogenesis but a very small amount of it can promote HFD-induced insulin resistance to a maximal level
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