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151.
Previous studies on biological pretreatment of switchgrass by solid-state fermentation with Acidothermus cellulolyticus 11B have shown that inhibitory compounds prevent growth on untreated switchgrass. A. cellulolyticus was grown in liquid medium containing cellobiose with phenolic monomers added to determine if the phenolic compounds are one possible source of inhibition. Cinnamic acid derivatives (trans-p-coumaric, trans-ferulic, and hydrocinnamic acids), hydroxybenzoic acids (p-hydroxybenzoic, syringic, and vanillic acids), benzaldehydes (vanillin and p-hydroxybenzaldehyde), and condensed tannin monomers (catechin and epicatechin) were tested at levels up to 20 mM. All compounds exhibited a dose-response relationship and strongly inhibited growth at 20 mM. trans-p-Coumaric acid was found to be the strongest inhibitor of A. cellulolyticus growth, with a specific growth rate of 0.004 h(-1) at 1 mM (0.18 h(-1) without phenolic monomer). GC-MS and HPLC methods were used to confirm the presence of these phenolic compounds in switchgrass and measure the amounts extracted using different conditions. The amounts of phenolic compounds measured were found to be higher than the threshold for growth inhibition. Leaching with water at 55°C was inefficient at removing bound phenolics, whereas NaOH treatment improved efficiency. Phenolic compounds spiked into alkaline pretreated switchgrass were also found to inhibit growth of A. cellulolyticus in solid-state fermentation. However, addition of insoluble polyvinylpolypyrrolidone (PVPP) to switchgrass improved growth of A. cellulolyticus in liquid cultures, providing a possible approach for alleviating microbial inhibition due to phenolic compounds in lignocellulose.  相似文献   
152.
Bats carry a variety of paramyxoviruses that impact human and domestic animal health when spillover occurs. Recent studies have shown a great diversity of paramyxoviruses in an urban-roosting population of straw-colored fruit bats in Ghana. Here, we investigate this further through virus isolation and describe two novel rubulaviruses: Achimota virus 1 (AchPV1) and Achimota virus 2 (AchPV2). The viruses form a phylogenetic cluster with each other and other bat-derived rubulaviruses, such as Tuhoko viruses, Menangle virus, and Tioman virus. We developed AchPV1- and AchPV2-specific serological assays and found evidence of infection with both viruses in Eidolon helvum across sub-Saharan Africa and on islands in the Gulf of Guinea. Longitudinal sampling of E. helvum indicates virus persistence within fruit bat populations and suggests spread of AchPVs via horizontal transmission. We also detected possible serological evidence of human infection with AchPV2 in Ghana and Tanzania. It is likely that clinically significant zoonotic spillover of chiropteran paramyxoviruses could be missed throughout much of Africa where health surveillance and diagnostics are poor and comorbidities, such as infection with HIV or Plasmodium sp., are common.  相似文献   
153.
154.
Photosystem II is responsible for the light-driven biological water-splitting system in oxygenic photosynthesis and contains a cluster of one calcium and four manganese ions at its water-oxidizing complex. This cluster may serve as a model for the design of artificial or biomimetic systems capable of splitting water into oxygen and hydrogen. In this study, we consider the ability of manganese oxide monosheets to self-assemble with organic compounds. Layered structures of manganese oxide, including guanidinium and imidazolium groups, were synthesized and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectrometry, and atomic absorption spectroscopy. The compounds can be considered as new structural models for the water-oxidizing complex of Photosystem II. The overvoltage of water oxidation for the compounds in these conditions at pH = 6.3 is ~0.6 V. These compounds may represent the first step to synthesize a hybrid of guanidinium or imidazole together with manganese as a biomimetic system for the water-oxidizing complex of Photosystem II.  相似文献   
155.
In diagnostic research challenges, quantitative real-time PCR (QPCR) has been widely utilized in gene expression analysis because of its sensitivity, accuracy, reproducibility, and most importantly, quantitativeness. Real-time PCR base kits are wildly applicable in cancer signaling pathways, especially in cancer investigations. T-cell acute lymphoblastic leukemia (T-ALL) is a type of leukemia that is more common in older children and teenagers. Deregulation of the Notch signaling pathway promotes proliferation and inhibits apoptosis of the lymphoblastic T cells. The aim of this study was to investigate the effect of Notch signaling activation on the expression of target genes using real-time QPCR and further use this method in clinical examination after validation. Two T-ALL cell lines, Jurkat and Molt-4, were used as models for activation of the Notch signaling via over-expression of the Notch1 intracellular domain. Expression analysis was performed for six downstream target genes (NCSTN, APH1, PSEN1, ADAM17, NOTCH1 and C-MYC) which play critical roles in the Notch signaling pathway. The results showed significant difference in the expression of target genes in the deregulated Notch signaling pathway. These results were also verified in 12 clinical samples bearing over-expression of the Notch signaling pathway. Identification of such downstream Notch target genes, which have not been studied inclusively, provides insights into the mechanisms of the Notch function in T cell leukemia, and may help identify novel diagnoses and therapeutic targets in acute lymphoblastic leukemia.  相似文献   
156.
Two-spotted spider mite, Tetranychus urticae Koch, is one of the most important pests of agricultural products that have a global distribution. Now, the control is dependent on the use of chemical pesticides. The effects of the sublethal concentrations (LC10 and LC25) of the essential oil of Cinnamomum zeylanicum were evaluated on some parameters of the life table of the pest, at the constant temperature of 30?°C, relative humidity of 40?±?5% and photoperiod of 16L: 8D. Our results showed that the essential oil of cinnamon is effective on female adult stage. Lethal concentration at which 50% mortality (LC50) for the essential oils is from C. zeylanicum on female adult mite was 23.39?μl/L air. Sublethal concentrations of the essential oil of C. zeylanicum also impair the natural biology of the mite. Concentrations of sublethal of essential oil decreased age-specific fertility (mx) of T. urticae compared with the control. Sublethal concentrations (LC10 and LC25) have reduced the life expectancy (ex) in egg stage. Sublethal effects of the essential oil of C. zeylanicum and its impact on T. urticae management are discussed.  相似文献   
157.
Natural killer cells, which play a pivotal role in the establishment and maintenance of normal pregnancy, are the most abundant leukocytes at the fetomaternal interface that their subsets frequencies and cytokine profile are influential factors in the preservation of the decidual tolerogenic microenvironment. Any imbalance in NK cells' frequency and functions could be associated with pregnancy failure. Mesenchymal stem cells (MSCs) are shown to have immunomodulatory effects on NK cells and their cytokine profile. The purpose of this study is to evaluate the impact of MSCs therapy on the cytokine profiles and subpopulations of NK cells in a murine model of recurrent pregnancy loss. Adipose-derived MSCs were injected intraperitoneally to the abortion-prone mice on Day 4.5 of gestation. The abortion rate was determined after MSCs administration and the frequency and cytokine profiles of the different subsets of NK cells were determined using the flow cytometry. Our results showed that, in abortion-prone mice, the frequency of CD49b+ NK cells was significantly higher than normal pregnant mice that decreased after therapy. We also demonstrated that MSCs downregulated the production of IFN-γ and upregulated IL-4 and IL-10 production by uNK cells. These findings indicate that MSCs can decrease the infiltration of CD49b+ NK cells to the fetomaternal interface and modulate the cytokine profile of NK cells from inflammatory to tolerogenic profile and thereby improve the tolerogenic microenvironment at the fetomaternal interface in benefit of pregnancy maintenance.  相似文献   
158.
Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is uncontrollably spread all over the world. The host immune responses strongly try to confront it with all the potential cells and cytokines. With chronically condition of SARS‐CoV‐2, natural killer cells and T cells become exhausted and decreasing their count leads to lymphopenia. Inability to eradicate the infected organ makes hyperinitiation of the immune system, which releases the excessive inflammatory cytokines to compensate the exhausted one as well as the low lymphocytes counts; it consequently leads to the cytokine storm syndrome. These mechanisms and the potential therapeutic targeting are discussed in this paper.  相似文献   
159.
Plasmonics - In this paper, a graphene-based patch antenna is proposed. The antenna structure is designed so that each of the various antenna sections affected by chemical potential changes can...  相似文献   
160.
International Journal of Peptide Research and Therapeutics - Hepatitis C virus (HCV) is an important causative agent of acute and chronic hepatitis. The non-structural protein 3 (NS3) of HCV...  相似文献   
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