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1.
Cephapirin, a cephalosporin antibiotic, is used by the majority of dairy farms in the US. Fecal and urinary excretion of cephapirin could introduce this compound into the environment when manure is land applied as fertilizer, and may cause development of bacterial resistance to antibiotics critical for human health. The environmental loading of cephapirin by the livestock industry remains un-assessed, largely due to a lack of appropriate analytical methods. Therefore, this study aimed to develop and validate a cephapirin quantification method to capture the temporal pattern of cephapirin excretion in dairy cows following intramammary infusion. The method includes an extraction with phosphate buffer and methanol, solid-phase extraction (SPE) clean-up, and quantification using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The LOQ values of the developed method were 4.02 µg kg−1 and 0.96 µg L−1 for feces and urine, respectively. This robust method recovered >60% and >80% cephapirin from spiked blank fecal and urine samples, respectively, with acceptable intra- and inter-day variation (<10%). Using this method, we detected trace amounts (µg kg−1) of cephapirin in dairy cow feces, and cephapirin in urine was detected at very high concentrations (133 to 480 µg L−1). Cephapirin was primarily excreted via urine and its urinary excretion was influenced by day (P = 0.03). Peak excretion (2.69 mg) was on day 1 following intramammary infusion and decreased sharply thereafter (0.19, 0.19, 0.08, and 0.17 mg on day 2, 3, 4, and 5, respectively) reflecting a quadratic pattern of excretion (Quadratic: P = 0.03). The described method for quantification of cephapirin in bovine feces and urine is sensitive, accurate, and robust and allowed to monitor the pattern of cephapirin excretion in dairy cows. This data will help develop manure segregation and treatment methods to minimize the risk of antibiotic loading to the environment from dairy farms. 相似文献
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Natural killer T (NKT) cells are a component of innate and adaptive immune systems implicated in immune, autoimmune responses and in the control of obesity and cancer. NKT cells develop from common CD4+ CD8+ double positive (DP) thymocyte precursors after the rearrangement and expression of T cell receptor (TCR) Vα14-Jα18 gene. Temporal regulation and late appearance of Vα14-Jα18 rearrangement in immature DP thymocytes has been demonstrated. However, the precise control of lifetime of DP thymocytes in vivo that enables distal rearrangements remains incompletely defined. Here we demonstrate that T cell factor (TCF)-1, encoded by the Tcf7 gene, is critical for the extended lifetime of DP thymocytes. TCF-1-deficient DP thymocytes fail to undergo TCR Vα14-Jα18 rearrangement and produce significantly fewer NKT cells. Ectopic expression of Bcl-xL permits Vα14-Jα18 rearrangement and rescues NKT cell development. We report that TCF-1 regulates expression of RORγt, which regulates DP thymocyte survival by controlling expression of Bcl-xL. We posit that TCF-1 along with its cofactors controls the lifetime of DP thymocytes in vivo. 相似文献
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Partha P. Majumder 《Current biology : CB》2010,20(4):R184-R187
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A hydrocarbon utilizing strain of Arthrobacter globiformis Lb isolated from local soil has been found to yield lysine 3.4 g l?1, keeping the medium optimal for pH, C- and N-sources. Addition of antibiotics and micronutrients to that optimal media stimulated cell growth and enhanced lysine yield. 相似文献
7.
Carlos A. Barrero Prasun K. Datta Satarupa Sen Satish Deshmane Shohreh Amini Kamel Khalili Salim Merali 《PloS one》2013,8(7)
Human immunodeficiency virus type 1 encoded viral protein Vpr is essential for infection of macrophages by HIV-1. Furthermore, these macrophages are resistant to cell death and are viral reservoir. However, the impact of Vpr on the macrophage proteome is yet to be comprehended. The goal of the present study was to use a stable-isotope labeling by amino acids in cell culture (SILAC) coupled with mass spectrometry-based proteomics approach to characterize the Vpr response in macrophages. Cultured human monocytic cells, U937, were differentiated into macrophages and transduced with adenovirus construct harboring the Vpr gene. More than 600 proteins were quantified in SILAC coupled with LC-MS/MS approach, among which 136 were significantly altered upon Vpr overexpression in macrophages. Quantified proteins were selected and clustered by biological functions, pathway and network analysis using Ingenuity computational pathway analysis. The proteomic data illustrating increase in abundance of enzymes in the glycolytic pathway (pentose phosphate and pyruvate metabolism) was further validated by western blot analysis. In addition, the proteomic data demonstrate down regulation of some key mitochondrial enzymes such as glutamate dehydrogenase 2 (GLUD2), adenylate kinase 2 (AK2) and transketolase (TKT). Based on these observations we postulate that HIV-1 hijacks the macrophage glucose metabolism pathway via the Vpr-hypoxia inducible factor 1 alpha (HIF-1 alpha) axis to induce expression of hexokinase (HK), glucose-6-phosphate dehyrogenase (G6PD) and pyruvate kinase muscle type 2 (PKM2) that facilitates viral replication and biogenesis, and long-term survival of macrophages. Furthermore, dysregulation of mitochondrial glutamate metabolism in macrophages can contribute to neurodegeneration via neuroexcitotoxic mechanisms in the context of NeuroAIDS. 相似文献
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Inducible nuclear expression of NF-kappa B in primary B cells stimulated through the surface Ig receptor 总被引:10,自引:0,他引:10
J L Liu T C Chiles R J Sen T L Rothstein 《Journal of immunology (Baltimore, Md. : 1950)》1991,146(5):1685-1691
Constitutive expression of NF-kappa B has been associated with developmental maturity in B cells on the basis of studies using continuously growing cell lines and plasmacytomas; however, little is known about the behavior of NF-kappa B in primary, mature B cells. In the present work, the regulation of NF-kappa B expression was studied by analyzing subcellular fractions of adult murine splenic B cells with the electrophoretic mobility shift assay using a kappa B-containing oligonucleotide. Although nuclear extracts from resting B cells contained kappa B-binding activity, additional kappa B-binding activity was present in cytosolic fractions in a form that became apparent after treatment with detergent. Competition analysis indicated that the DNA binding activity detected by electrophoretic gel mobility shift assay was specific for the kappa B motif, and UV photo-cross-linking showed the molecular size of kappa B-binding protein to be similar to that of the DNA binding subunit of NF-kappa B. Nuclear expression of kappa B-binding activity was markedly induced by treatment of B cells with phorbol ester or with LPS. Most notably, kappa B-binding activity was induced after surface IgR cross-linking, and the mechanism of this induction involved PKC. Further, anti-Ig-induced activity was superinduced in the presence of cycloheximide. These results indicate that nuclear NF-kappa B is rapidly induced as a result of B cell stimulation, and further suggest that NF-kappa B may play a specific role in mature B cells after ligand binding to surface Ig distinct from its postulated developmental role as a stage-specific factor involved in kappa-enhancer function. 相似文献
9.
Sarkar Avipsha Sen Shampa 《International journal of peptide research and therapeutics》2020,26(1):209-223
International Journal of Peptide Research and Therapeutics - Computer Aided Drug Discovery (CADD) has become a vital tool for the rapid identification of new candidate molecules prior to their... 相似文献
10.
Interspecific transformation in Azotobacter 总被引:8,自引:0,他引:8