n-Dodecyl β-D-maltoside specifically competes with general anesthetics for anesthetic binding sites

We recently demonstrated that the anionic detergent sodium dodecyl sulfate (SDS) specifically interacts with the anesthetic binding site in horse spleen apoferritin, a soluble protein which models anesthetic binding sites in receptors. This raises the possibility of other detergents similarly interacting with and occluding such sites from anesthetics, thereby preventing the proper identification of novel anesthetic binding sites. n-Dodecyl β-D-maltoside (DDM) is a non-ionic detergent commonly used during protein-anesthetic studies because of its mild and non-denaturing properties. In this study, we demonstrate that SDS and DDM occupy anesthetic binding sites in the model proteins human serum albumin (HSA) and horse spleen apoferritin and thereby inhibit the binding of the general anesthetics propofol and isoflurane. DDM specifically interacts with HSA (K_d?=?40?μM) with a lower affinity than SDS (K_d?=?2?μM). DDM exerts all these effects while not perturbing the native structures of either model protein. Computational calculations corroborated the experimental results by demonstrating that the binding sites for DDM and both anesthetics on the model proteins overlapped. Collectively, our results indicate that DDM and SDS specifically interact with anesthetic binding sites and may thus prevent the identification of novel anesthetic sites. Special precaution should be taken when undertaking and interpreting results from protein-anesthetic investigations utilizing detergents like SDS and DDM.     

Brown drug substance color investigation in cell culture manufacturing using chemically defined media: A case study

Drug substance (DS) color is an important quality attribute for release, stability and comparability studies of biologics. With the increase of DS concentrations and biologics pipelines made in chemically defined media, atypical DS color other than colorless or pale yellow has been recently reported in the biopharmaceutical industry. We recently observed a brown DS color in manufacturing. Although analytical characterization data indicated that the brown color DS had no major quality issue, it is necessary to find the root cause and reduce DS color to ease placebo design for clinical use. It was demonstrated that the brown color was caused by the chemically defined basal medium containing high levels of iron and vitamin B12 (VB12) regardless of cell lines. Iron caused tryptophan oxidation in the protein to form N-formylkynurenine and kynurenine products, which likely contributed to a yellow DS color. A pink DS color was caused by the residual VB12 bound to DS. The brown color was the result of the combinatory effect of yellow and pink colors. Finally a modified basal medium was developed to produce a pale yellow DS in manufacturing.     

Understanding telomerase in cancer stem cell biology

Comment on: Vicente-Dueñas C, et al. Oncotarget 2012; Epub ahead of print; PMID:22408137.     

Drugs derived from phage display: From candidate identification to clinical practice

Phage display, one of today’s fundamental drug discovery technologies, allows identification of a broad range of biological drugs, including peptides, antibodies and other proteins, with the ability to tailor critical characteristics such as potency, specificity and cross-species binding. Further, unlike in vivo technologies, generating phage display-derived antibodies is not restricted by immunological tolerance. Although more than 20 phage display-derived antibody and peptides are currently in late-stage clinical trials or approved, there is little literature addressing the specific challenges and successes in the clinical development of phage-derived drugs. This review uses case studies, from candidate identification through clinical development, to illustrate the utility of phage display as a drug discovery tool, and offers a perspective for future developments of phage display technology.     

致病性念珠菌对常见抗真菌药物的耐药性研究进展

近年来,致病性念珠菌感染引起的侵袭性念珠菌病患者人数逐年增多。白念珠菌仍是引起感染的主要致病菌,但是由非白念念珠菌引起的感染比例显著升高。致病性念珠菌对常见抗真菌药物的耐药现象呈上升趋势,这是导致临床治疗其所致的侵袭性感染失败的重要原因之一。本文就致病性念珠菌耐药性的流行病学以及其耐药机制方面的研究进展进行了介绍。     

Odoriferous Therapy: A Review Identifying Essential Oils against Pathogens of the Respiratory Tract

This review explores the body of scientific information available on the antimicrobial properties of essential oils against pathogens responsible for respiratory infections and critically compares this to what is recommended in the Layman's aroma‐therapeutic literature. Essential oils are predominantly indicated for the treatment of respiratory infections caused by bacteria or viruses (total 79.0 %), the efficacy of which has not been confirmed through clinical trials. When used in combination, they are often blended for presumed holistic synergistic effects. Of the essential oils recommended, all show some degree of antioxidant activity, 50.0 % demonstrate anti‐inflammatory effects and 83.3 % of the essential oils showed antihistaminic activity. Of the essential oils reviewed, 43.8 % are considered non‐toxic while the remaining essential oils are considered slightly to moderately toxic (43.7 %) or the toxicity is unknown (12.5 %). Recommendations are made for further research into essential oil combinations.     

Three proline rotamases involved in calcium homeostasis play differential roles in stress tolerance,virulence and calcineurin regulation of Beauveria bassiana

FK506‐sensitive proline rotamases (FPRs), also known as FK506‐binding proteins (FKBPs), can mediate immunosuppressive drug resistance in budding yeast but their physiological roles in filamentous fungi remain opaque. Here, we report that three FPRs (cytosolic/nuclear 12.15‐kD Fpr1, membrane‐associated 14.78‐kD Fpr2 and nuclear 50.43‐kD Fpr3) are all equally essential for cellular Ca²⁺ homeostasis and contribute significantly to calcineurin activity at different levels in the insect‐pathogenic fungus Beauveria bassiana although the deletion of fpr1 alone conferred resistance to FK506. Radial growth, conidiation, conidial viability and virulence were less compromised in the absence of fpr1 or fpr2 than in the absence of fpr3, which abolished almost all growth on scant media and reduced growth moderately on rich media. The Δfpr3 mutant was more sensitive to Na⁺, K⁺, Mn²⁺, Ca²⁺, Cu²⁺, metal chelate, heat shock and UVB irradiation than was Δfpr2 while both mutants were equally sensitive to Zn²⁺, Mg²⁺, Fe²⁺, H₂O₂ and cell wall‐perturbing agents. In contrast, the Δfpr1 mutant was less sensitive to fewer stress cues. Most of 32 examined genes involved in DNA damage repair, Na⁺/K⁺ detoxification or osmotolerance and Ca²⁺ homeostasis were downregulated sharply in Δfpr2 and Δfpr3 but rarely so affected in Δfpr1, coinciding well with their phenotypic changes. These findings uncover important, but differential, roles of three FPRs in the fungal adaptation to insect host and environment and provide novel insight into their essential roles in calcium signalling pathway.     

Targeting selective autophagy by AUTAC degraders

ABSTRACT

Targeted degradation is a promising new modality in drug discovery that makes it possible to reduce intracellular protein levels with small molecules. It is a complementary approach to the conventional protein knockdown typically used in laboratories and may offer a way to approach the currently undruggable human proteome. Recently, the first autophagy-mediated degraders, called AUTACs, were developed based on observations in a xenophagy study.     

Experimental models of maternal–fetal interface and their potential use for nanotechnology applications

During pregnancy, the placenta regulates the transfer of oxygen, nutrients, and residual products between the maternal and fetal bloodstreams and is a key determinant of fetal exposure to xenobiotics from the mother. To study the disposition of substances through the placenta, various experimental models are used, especially the perfused placenta, placental villi explants, and cell lineage models. In this context, nanotechnology, an area of study that is on the rise, enables the creation of particles on nanometric scales capable of releasing drugs aimed at specific tissues. An important reason for furthering the studies on transplacental transfer is to explore the potential of nanoparticles (NPs), in new delivery strategies for drugs that are specifically aimed at the mother, the placenta, or the fetus and that involve less toxicity. Due to the fact that the placental barrier is essential for the interaction between the maternal and fetal organisms as well as the possibility of NPs being used in the treatment of various pathologies, the aim of this review is to present the main experimental models used in studying the maternal–fetal interaction and the action of NPs in the placental environment.