Effects of chloride on paramagnetic coupling of manganese in calcium chloride-washed photosystem II preparations

The effect of chloride on paramagnetic coupling of manganese in the oxygen-evolving complex of CaCl2--washed PS II preparations was examined using Q-band ESR. When these PS II preparations were depleted of chloride, a strong 6-line ESR signal characteristic of protein-bound, uncoupled manganese was observed. Incubation at high chloride concentrations caused the disappearance of this signal. By repeated removal and addition of chloride, the signal could be cycled on and off without loss of bound manganese. When in a chloride-depleted state, the ESR-detectable protein-bound manganese could be removed by treatment with EDTA. Subsequent heating of EDTA-treated preparations revealed a second pool of protein-bound manganese associated with PS II. One of these pools requires a high concentration of chloride to maintain paramagnetic coupling while the second pool (within the limits of our observations) does not appear to require chloride for the maintenance of the paramagnetically coupled state. © 1986

Predictions Generated from a Simulation Engine for Gene Expression Micro-arrays for use in Research Laboratories

In this paper we introduce the technical components, the biology and data science involved in the use of microarray technology in biological and clinical research. We discuss how laborious experimental protocols involved in obtaining this data used in laboratories could benefit from using simulations of the data. We discuss the approach used in the simulation engine from [7]. We use this simulation engine to generate a prediction tool in Power BI, a Microsoft, business intelligence tool for analytics and data visualization [22]. This tool could be used in any laboratory using micro-arrays to improve experimental design by comparing how predicted signal intensity compares to observed signal intensity. Signal intensity in micro-arrays is a proxy for level of gene expression in cells. We suggest further development avenues for the prediction tool

Photosystem 2 Remains Capable of Oxygen Evolution After Losing 1/4 of its Initial Manganese Content

Photosystem 2 (PS 2) membranes were treated with CaCl2 to remove extrinsic polypeptides. After resuspension in a chloride-free buffer, manganese was extracted by leaching or with EDTA. Measurements made using three different methods (electron paramagnetic resonance, kinetics, and direct Mn analysis) agreed that one-fourth of the initial Mn content was lost and that the membrane preparation remained homogenous. Upon readdition of extrinsic polypeptides, the Mn-depleted membranes were capable of oxygen evolution. Thus not all the Mn in PS 2 is necessary for the oxygen evolution function

Predictions Generated from a Simulation Engine for Gene Expression Micro-arrays for use in Research Laboratories

In this paper we introduce the technical components, the biology and data science involved in the use of microarray technology in biological and clinical research. We discuss how laborious experimental protocols involved in obtaining this data used in laboratories could benefit from using simulations of the data. We discuss the approach used in the simulation engine from [7]. We use this simulation engine to generate a prediction tool in Power BI, a Microsoft, business intelligence tool for analytics and data visualization [22]. This tool could be used in any laboratory using micro-arrays to improve experimental design by comparing how predicted signal intensity compares to observed signal intensity. Signal intensity in micro-arrays is a proxy for level of gene expression in cells. We suggest further development avenues for the prediction tool

Purification of a Tat-associated kinase reveals a TFIIH complex that modulates HIV-1 transcription.

The Tat protein is a transcriptional activator which is required for efficient human immunodeficiency virus 1 (HIV-1) gene expression Tat stimulates HIV-1 transcriptional elongation by increasing the processivity of RNA polymerase II. To address whether Tat-mediated effects on HIV-1 gene expression are due to modulation in the phosphorylation of the RNA polymerase II C-terminal domain (CTD), we developed a purification protocol to identify cellular kinases that are capable of binding to Tat and hyperphosphorylating the RNA polymerase II CTD. A 600 kDa protein complex with these properties was isolated, and specific components were identified using peptide microsequence analysis. This analysis indicated that proteins comprising the multi-subunit TFIIH complex, in addition to several novel factors, were associated with Tat using both in vitro and in vivo analysis. The Tat-associated kinase bound to the activation domain of Tat, and its ability to hyperphosphorylate RNA polymerase II was markedly stimulated by Tat. Furthermore, the addition of the Tat-associated kinase to in vitro transcription assays stimulated the ability of Tat to activate HIV-1 transcription. These results define a cellular kinase complex whose activity is modulated by Tat to result in activation of HIV-1 trancription