The Human Papillomavirus Type 11 E1∧E4 Protein Is Phosphorylated in Genital Epithelium

AbstractThe most abundant viral transcript in human papillomavirus (HPV) 11-infected xenograft tissue has been shown to encode the E1∧E4 protein. The function of E1∧E4 protein has not been determined. Several potential phosphorylation sequence motifs were identified in the HPV 11 E1∧E4 protein, including potential sites of phosphorylation by mitogen-activated protein kinase (MAPK), cAMP-dependent protein kinase (PKA), casein kinase II, and protein kinase C. To test phosphorylation of the HPV 11 E1∧E4 protein, a soluble maltose binding protein (MBP) fusion was produced in Escherichia coli. Only MAPK and PKA phosphorylated the E1∧E4 protein. Phosphoamino acid analysis showed that one or more threonine residues were phosphorylated by MAPK, and both serine and threonine residues were phosphorylated by PKA. MBP–E1∧E4 mutant proteins were designed to delineate the E1∧E4 phosphoacceptor residues. MAPK was shown to phosphorylate E1∧E4 on threonine 53 within a MAPK consensus phorphorylation sequence motif. PKA was shown to phosphorylate E1∧E4 at two residues: threonine 36 within a consensus motif and serine 44 within a variant of the PKA consensus phosphorylation sequence motif. HPV 11-infected human genital tissue grown as a xenograft in an athymic mouse was labeled with [32P]orthophosphate. Phosphoamino acid analysis of E1∧E4 protein immunoprecipitated from 32P-labeled tissue revealed that both serine and threonine residues were phosphorylated. Analysis by liquid chromatography–mass spectrophotometry was consistent with phosphorylation of residues within the PKA and MAPK phosphorylation sequence motifs. Expression of E1∧E4 protein containing phosphorylation substitution mutations showed that the PKA mutant did not differ from wild-type E1∧E4 protein in intracellular distribution. In contrast, the MAPK mutant did not localize exclusively to the cytoplasm nor did it colocalize with wild-type E1∧E4 protein. We conclude that HPV 11 E1∧E4 protein is phosphorylated in vitro and in vivo. Our data are consistent with phosphorylation of HPV 11 E1∧E4 protein by MAPK and PKA in infected tissue

Is the High Frequency of Postoperative Atrial Fibrillation after Cardiac and Lung Surgeries Related to Hypomagnesemia and Releases of Ceramides and Platelet-Activating Factor?

The authors discuss the possible role of hypomagnesemia, ceramides and platelet-activating factor in the incidence of postoperative atrial fibrillation after cardiac and lung surgeries

Euphoria from Drinking Alcoholic Beverages May Be Due to Reversible Constriction of Cerebral Blood Vessels: Potential Roles of Unrecognized Ionized Hypomagnesemia, and Release of Ceramides and Platelet-Activating Factor

The authors discuss the feeling of euphoria when drinking alcohol. They summarize studies that suggest this feeling is due to blood vessel constriction, and explain why they believe that the specific mechanism that results in euphoria is the rapid, reversible release o free magnesium ions ([Mg2+]) coupled to the release of ceramides and platelet-activating factor (PAF)

Sudden Cardiac Death in Infants, Children and Young Adults: Possible Roles of Dietary Magnesium Intake and Generation of Platelet-Activating Factor in Coronary Arteries

Magnesium (Mg) is a co-factor for more than 500 enzymes, and is the second most abundant intracellular cation after potassium. It is vital in numerous physiological, cellular and biochemical functions and systems necessary for life. Approximately 35 years ago, our laboratory suggested that a progressive, dietary deficiency and/or metabolic induced loss of Mg from the body, beginning early in life, particularly during development of the coronary arteries, could lead to coronary arterial vasospasm, ischemic heart disease, and sudden-cardiac death (SCD). Herein, we review evidence for a brand-new, novel hypothesis which combines knowledge suggesting a combined role for hypomagnesemia and platelet-activating factor (PAF) which may provide insights into unexplained SCD in infants, children, and young adults. This review documents what takes place in the cardiovascular system when the body and its tissues are subjected to lower than normal dietary Mg intake, and also provides new evidence for a series of heretofore unknown actions of PAF that are most likely involved and/or trigger coronary arterial vasospasm in the presence of low concentrations of ionized Mg levels. The roles of vascular remodeling, NF-κB and proto-oncogenes are considered to play major roles in this hypothesis

The Expression of Platelet-Activating Factor Is Induced by Low Extracellular Mg2+ in Aortic, Cerebral and Neonatal Coronary Vascular Smooth Muscle; Cross Talk with Ceramide Production, NF–kB and Proto-Oncogenes: Possible Links to Atherogenesis and Sudden Cardiac Death in Children and Infants, and Aging: Hypothesis, Review and Viewpoint

An attempt is made, herein, to reconcile, and integrate, various phenomena associated with magnesium deficiency (MgD) in cardiovascular health, disease, and aging as well as reasons for the high incidence of sudden cardiac death in infants and young adults. With new experiments, we demonstrate, for the first time, that very low concentrations of platelet-activating factor (PAF), when added to primary cultured cerebral, neonatal coronary, and aortic vascular smooth muscle (VSM) cells (from three different mammals) promote rapid rises in free intracellular Ca2+ ions and a significant, concomitant reduction in free intracellular Mg2+ ions; these actions of PAF being curtailed with a specific membrane-receptor inhibitor of PAF. Our new experiments also demonstrate that addition of PAF to the VSM cells result in activation of NF-kB, activation of the proto-oncogenes c-fos and c-jun, a generation/release of ceramide, and synthesis of DNA; most of these actions being inhibited by a specific membrane-receptor antagonist of PAF. In addition, we show, for the first time, formation of 4-hydroxy-2-nonenal (4-HNE) in VSM cells incubated in Mg-deficient (MgD) environments or after addition of PAF. This is important because 4-HNE is a well-known inducer of hydrogen peroxide, known to be formed in MgD VSM cells and that 4-HNE is known to induce DNA damage and fragmentation, events that we have shown previously in VSM and cardiac muscle cells exposed to low Mg environments. Lastly, our experiments demonstrate that incubation of cerebral, neonatal coronary and aortic VSM cells in low Mg2+ induces: 1. rapid formation of PAF which can be attenuated greatly with a specific membrane-receptor antagonist of PAF; and 2. rises in cellular levels of ceramide, NF-kB activation and formation of the proto-oncogenes, and synthesis of DNA, all of which could be inhibited with a specific membrane-receptor antagonist of PAF. These new findings suggest major roles for PAF (and probably PAF-like lipids) and ceramide formation in the cardiovascular manifestations of MgD, inflammation, atherogenesis, aging, and sudden cardiac death in children. The significance of our new findings are reviewed in light of other works on MgD, inflammation, atherogenesis, sudden cardiac death, and aging

Why Is There an Association Between Retinal Vein Occlusion, Vision Loss, Myocardial Infarction, Stroke and Mortality: Potential Roles of Hypomagnesaemia, Release of Sphingolipids, and Platelet-Activating Factor

Although numerous hypotheses (and potential risk factors), have been offered to explain the origins and potential mechanism(s) for central retinal vein occlusion (RVO) in patients of diverse ages, there is no agreement. Recently, considerable epidemiological evidence has been brought forth which indicates a strong association between RVO, myocardial infarctions, heart failure, and stroke. Magnesium (Mg) deficiency (mgD) has long-been associated with glaucoma and diabetic retinopathy. Over the past three decades, our laboratories have found strong associations of mgD linked to morbidity/ mortality in cardiovascular diseases such as myocardial infarctions, cardiac failure, atherogenesis, and strokes, both experimentally and clinically. More recently, we have reported direct links of mgD in these disease syndromes with generation and release of ceramides and platelet-activating factor (PAF). In this report, we present a novel hypothesis for a probable underlying mgD and release of ceramides and PAF as causal factors in development and progression of RVO. We believe this hypothesis could prove useful in the diagnosis and treatment of RVO

Diradical intermediate within the context of tryptophan tryptophylquinone biosynthesis

Despite the importance of tryptophan (Trp) radicals in biology, very few radicals have been trapped and characterized in a physiologically meaningful context. Here we demonstrate that the diheme enzyme MauG uses Trp radical chemistry to catalyze formation of a Trp-derived tryptophan tryptophylquinone cofactor on its substrate protein, premethylamine dehydrogenase. The unusual six-electron oxidation that results in tryptophan tryptophylquinone formation occurs in three discrete two-electron catalytic steps. Here the exact order of these oxidation steps in the processive six-electron biosynthetic reaction is determined, and reaction intermediates are structurally characterized. The intermediates observed in crystal structures are also verified in solution using mass spectrometry. Furthermore, an unprecedented Trp-derived diradical species on premethylamine dehydrogenase, which is an intermediate in the first two-electron step, is characterized using high-frequency and -field electron paramagnetic resonance spectroscopy and UV-visible absorbance spectroscopy. This work defines a unique mechanism for radical-mediated catalysis of a protein substrate, and has broad implications in the areas of applied biocatalysis and understanding of oxidative protein modification during oxidative stress

Applications of long period gratings in solid core photonic bandgap fibers

Solid core photonic bandgap fibres are photonic crystal fibres with a solid core surrounded by high index inclusions. The guidance properties of these fibers are very sensitive to the refractive index of the inclusions, making them widely tunable and making them very promising for sensing applications. Combining these fibers with long period gratings unleashes their full potential, enabling narrow band notch filters tunable over hundreds of nm, refractive index sensors with sensitivity comparable to that of surface plasmon resonance sensors, but also the extraction of the full band diagrams of these bandgap fibres

Sensitivity Analysis and Optimization Using Energy Finite Element and Boundary Element Methods

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76597/1/AIAA-20811-196.pd

Thermodynamic Simulation of the RDX-Aluminum Interface Using ReaxFF Molecular Dynamics

We use reactive molecular dynamics (RMD) simulations to study the interface between cyclotrimethylene trinitramine (RDX) and aluminum (Al) with different oxide layers to elucidate the effect of nanosized Al on thermal decomposition of RDX. A published ReaxFF force field for C/H/N/O elements was retrained to incorporate Al interactions and then used in RMD simulations to characterize compound energetic materials. We find that the predicted adsorption energies for RDX on the Al(111) surface and the apparent activation energies of RDX and RDX/Al are in agreement with ab initio calculations. The Al(111) surface-assisted decomposition of RDX occurs spontaneously without potential barriers, but the decomposition rate becomes slow when compared with that for RDX powder. We also find that the Al(111) surface with an oxide layer (Al oxide) slightly increases the potential barriers for decomposition of RDX molecules, while α-Al_2O_3(0001) retards thermal decomposition of RDX, due to the changes in thermal decomposition kinetics. The most likely mechanism for the thermal decomposition of RDX powder is described by the Avrami–Erofeev equation, with n = 3/4, as random nucleation and subsequent growth model. Although the decomposition mechanism of RDX molecules in the RDX/Al matrix complies with three-dimensional diffusion, Jander’s equation for RDX(210)/Al oxide and the Zhuralev–Lesokin–Tempelman (Z-L-T) equation for RDX(210)/Al_2O_3(0001) provide a more accurate description. We conclude that the origin of these differences in dynamic behavior is due to the variations in the oxide layer morphologies