Differential regulation of Ota and Otb, two primary glycine betaine transporters in the methanogenic archaeon Methanosarcina mazei go1

Methanogenic archaea accumulate glycine betaine in response to hypersalinity, but the regulation of proteins involved, their mechanism of activation and regulation of the corresponding genes are largely unknown. Methanosarcina mazei differs from most other methanoarchaea in having two gene clusters both encoding a potential glycine betaine transporter, Ota and Otb. Western blot as well as quantitative real-time PCR revealed that Otb is not regulated by osmolarity. On the other hand, cellular levels of Ota increased with increasing salt concentrations. A maximum was reached at 300-500 m M NaCl. Ota concentrations reached a maximum 4 h after an osmotic upshock. Hyperosmolarity also caused an increase in cellular Ota concentrations. In addition to osmolarity Ota expression was regulated by the growth phase. Expression of Ota as well as transport of betaine was downregulated in the presence of glycine betaine. Copyright (c) 2007 S. Karger AG, Basel

Cell cycle plasticity underlies fractional resistance to palbociclib in ER+/HER2− breast tumor cells

The CDK4/6 inhibitor palbociclib blocks cell cycle progression in Estrogen receptor-positive, human epidermal growth factor 2 receptor-negative (ER+/HER2-) breast tumor cells. Despite the drug's success in improving patient outcomes, a small percentage of tumor cells continues to divide in the presence of palbociclib-a phenomenon we refer to as fractional resistance. It is critical to understand the cellular mechanisms underlying fractional resistance because the precise percentage of resistant cells in patient tissue is a strong predictor of clinical outcomes. Here, we hypothesize that fractional resistance arises from cell-to-cell differences in core cell cycle regulators that allow a subset of cells to escape CDK4/6 inhibitor therapy. We used multiplex, single-cell imaging to identify fractionally resistant cells in both cultured and primary breast tumor samples resected from patients. Resistant cells showed premature accumulation of multiple G1 regulators including E2F1, retinoblastoma protein, and CDK2, as well as enhanced sensitivity to pharmacological inhibition of CDK2 activity. Using trajectory inference approaches, we show how plasticity among cell cycle regulators gives rise to alternate cell cycle "paths" that allow individual tumor cells to escape palbociclib treatment. Understanding drivers of cell cycle plasticity, and how to eliminate resistant cell cycle paths, could lead to improved cancer therapies targeting fractionally resistant cells to improve patient outcomes

Specifically decreased collagen biosynthesis in scurvy dissociated from an effect on proline hydroxylation and correlated with body weight loss. In vitro studies in guinea pig calvarial bones.

The question whether ascorbate regulates collagen production solely through its direct role in proline hydroxylation was investigated. Proteins in calvarial bones from control and scorbutic weanling guinea pigs were labeled in short-term cultures with radioactive proline. Proteins were digested with purified bacterial collagenase to distinguish between effects on collagen polypeptide production and hydroxyproline formation. There was a preferential decrease in the absolute rate of collagen biosynthesis beginning after 2 wk of ascorbate deficiency, and this effect was temporally dissociated from decreased proline hydroxylation. There were no significant changes in the absolute rates of collagen degradation or noncollagen protein production. In vitro inhibition of proline hydroxylation in normal bone with alpha, alpha'-dipyridyl did not affect the relative rate of collagen synthesis, further dissociating these functions. Ascorbate added to scorbutic bone cultures reversed defective proline hydroxylation but not defective collagen synthesis, suggesting that the latter was an indirect effect of scurvy. There was a linear correlation between the extent of body weight lost during the 3rd and 4th wk of scurvy and the rate of collagen synthesis in scorbutic bone. This correlation also applied to control animals receiving ascorbate, but with weight loss induced by food restriction. These studies establish for the first time that ascorbate deficiency in guinea pigs leads to a specific decrease in collagen polypeptide synthesis and suggest that this decrease results from the reduced food intake and/or weight-loss characteristic of scurvy

Long-Term Lipid Effects of Pioglitazone by Baseline Anti-Hyperglycemia Medication Therapy and Statin Use from the PROactive Experience (PROactive 14)

Studies have shown that pioglitazone treatment in patients with type 2 diabetes mellitus can improve parameters of diabetic dyslipidemia. The aim of this study was to examine the effect of pioglitazone on triglycerides, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol levels in patients from the Prospective Pioglitazone Clinical Trial in Macrovascular Events (PROactive) to determine whether pioglitazone-induced lipid effects were altered by different baseline antihyperglycemia medication or statin use. PROactive was a long-term, randomized, double-blind, cardiovascular outcomes study in patients with type 2 diabetes at high cardiovascular risk who had pioglitazone or placebo added to existing treatment. The present post hoc study analyzed lipid results from patients who received different baseline antihyperglycemia regimens and the presence or absence of baseline statin use. Independent of antihyperglycemia medication and statin use, triglyceride levels decreased in all subgroups treated with pioglitazone (-9.9% to -12.3%), whereas little change was observed in placebo groups. High-density lipoprotein cholesterol increased nearly twice as much with pioglitazone (18.1% to 20.3%) as with placebo (8.1% to 11.8%) across all subgroups. Low-density lipoprotein cholesterol increased moderately with pioglitazone (5.2% to 9.6%) compared with placebo (3.3% to 7.6%) (placebo-adjusted range 1.11% to 4.37%). In conclusion, long-term pioglitazone therapy led to durable improvements in triglyceride and high-density lipoprotein cholesterol levels, irrespective of baseline antihyperglycemia therapy or statin use. (C) 2009 Published by Elsevier Inc. (Am J Cardiol 2009;104:234-239

Nanostructured LiMPO

Nanostructured materials are considered to be strong candidates for fundamental advances in efficient storage and/or conversion. In nanostructured materials transport kinetics and surface processes play determining roles. This work describes recent developments in the synthesis and characterization of composites which consist of lithium metal phosphates (LiMPO4, M = Fe, Mn, Co, Ni) coated on nanostructured carbon supports (unordered nanofibers, foams). The composites have been prepared by coating the carbon structures in aqueous (or polyols) solutions containing lithium, metal ions and phosphates. After drying out, the composites have been thermally treated at different temperatures (between 600-780°C) for 5-12 hours under nitrogen. The formation of the olivine structured phase was confirmed by the X-ray diffraction analysis on powders prepared under very similar conditions. The surface investigation revealed the formation of an homogeneous coating of the olivine phase on the carbon structures. The electrochemical performance on the composites showed a dramatic improvement of the discharge specific capacity (measured at a discharge rate of C/25 and room temperature) compared to the prepared powders. The delivered values were 105 mAhg-1 for M = Fe, 100 mAhg-1 for M = Co, 70 mAhg-1 for M = Mn and 30 mAhg-1 for M = Ni respectively