RNAi experiments are ubiquitously used in cell biology and are achieved by transfection of small interfering RNAs (siRNAs) into cells using a transfection reagent. These results in knock‐down of proteins of interest, and the phenotypic consequences are then analyzed. It is reported here that two common RNA interference (RNAi) transfection reagents, DharmaFECT 1 and INTERFERin, in mock transfections using non‐targeting siRNAs, cause alterations in the lipidome of HeLa cells. Some lipids change in response to both, presumably chemically different, transfection reagents, while other lipid species change only in response to one of the reagents. While the functional implications of these lipidomic alterations remain to be investigated, the authors' experiments suggest that it is important to use appropriate mock transfection controls during RNAi experiments, ideally complemented by an orthogonal perturbation, especially when investigating membrane‐associated phenomena. 相似文献
Around the world, many species are confined to “Sky Islands,” with different populations in isolated patches of montane habitat. How does this pattern arise? One scenario is that montane species were widespread in lowlands when climates were cooler, and were isolated by local extinction caused by warming conditions. This scenario implies that many montane species may be highly susceptible to anthropogenic warming. Here, we test this scenario in a montane lizard (Sceloporus jarrovii) from the Madrean Sky Islands of southeastern Arizona. We combined data from field surveys, climate, population genomics, and physiology. Overall, our results support the hypothesis that this species' current distribution is explained by local extinction caused by past climate change. However, our results for this species differ from simple expectations in several ways: (a) their absence at lower elevations is related to warm winter temperatures, not hot summer temperatures; (b) they appear to exclude a low‐elevation congener from higher elevations, not the converse; (c) they are apparently absent from many climatically suitable but low mountain ranges, seemingly “pushed off the top” by climates even warmer than those today; (d) despite the potential for dispersal among ranges during recent glacial periods (~18,000 years ago), populations in different ranges diverged ~4.5–0.5 million years ago and remained largely distinct; and (e) body temperatures are inversely related to climatic temperatures among sites. These results may have implications for many other Sky Island systems. More broadly, we suggest that Sky Island species may be relevant for predicting responses to future warming. 相似文献
Waxes are components of the cuticle covering the aerial organs of plants. Accumulation of waxes has previously been associated with protection against water loss, therefore contributing to drought tolerance. However, not much information is known about the function of individual wax components during water deficit. We studied the role of wax ester synthesis during drought. The wax ester load on Arabidopsis leaves and stems was increased during water deficiency. Expression of three genes, WSD1, WSD6 and WSD7 of the wax ester synthase/diacylglycerol acyltransferase (WS/DGAT or WSD) family was induced during drought, salt stress and abscisic acid treatment. WSD1 has previously been identified as the major wax ester synthase of stems. wsd1 mutants have shown reduced wax ester coverage on leaves and stems during normal or drought condition, while wax ester loads of wsd6, wsd7 and of the wsd6wsd7 double mutant were unchanged. The growth and relative water content of wsd1 plants were compromised during drought, while leaf water loss of wsd1 was increased. Enzyme assays with recombinant proteins expressed in insect cells revealed that WSD6 and WSD7 contain wax ester synthase activity, albeit with different substrate specificity compared with WSD1. WSD6 and WSD7 localize to the endoplasmic reticulum (ER)/Golgi. These results demonstrated that WSD1 is involved in the accumulation of wax esters during drought, while WSD6 and WSD7 might play other specific roles in wax ester metabolism during stress. 相似文献
In this work, an overview of the biosimilars market, pipeline and industry targets is discussed. Biosimilars typically have a shorter timeline for approval (8 years) compared to 12 years for innovator drugs and the development cost can be 10–20% of the innovator drug. The biosimilar pipeline is reviewed as well as the quality management system (QMS) that is needed to generate traceable, trackable data sets. One difference between developing a biosimilar compared to an originator is that a broader analytical foundation is required for biosimilars and advances made in developing analytical similarity to characterize these products are discussed. An example is presented on the decisions and considerations explored in the development of a biosimilar and includes identification of the best process parameters and methods based on cost, time, and titer. Finally factors to consider in the manufacture of a biosimilar and approaches used to achieve the target-directed development of a biosimilar are discussed.
PrrC is a Sco homologue in Rhodobacter sphaeroides that is associated with PrrBA, a two-component signal transduction system that induces photosynthesis gene expression in response to a decrease in oxygen tension. Although Sco proteins have been shown to bind copper the observation that they are structurally-related to thioredoxins suggested that they might possess thiol-disulfide oxidoreductase activity. Our results show that PrrC reduces Cu(2+) to Cu(+) and possesses disulfide reductase activity. These results indicate that some bacterial Sco proteins may have biochemical properties that are distinct from those of mitochondrial Sco proteins. 相似文献
Recent developments indicate that the regeneration of beta cell function and mass in patients with diabetes is possible. A regenerative approach may represent an alternative treatment option relative to current diabetes therapies that fail to provide optimal glycemic control. Here we report that the inactivation of GSK3 by small molecule inhibitors or RNA interference stimulates replication of INS-1E rat insulinoma cells. Specific and potent GSK3 inhibitors also alleviate the toxic effects of high concentrations of glucose and the saturated fatty acid palmitate on INS-1E cells. Furthermore, treatment of isolated rat islets with structurally diverse small molecule GSK3 inhibitors increases the rate beta cell replication by 2-3-fold relative to controls. We propose that GSK3 is a regulator of beta cell replication and survival. Moreover, our results suggest that specific inhibitors of GSK3 may have practical applications in beta cell regenerative therapies. 相似文献
Bacterial mechanosensitive channels are activated by increases in tension in the lipid bilayer of the cytoplasmic membrane, where they transiently create large pores in a controlled manner. Mechanosensitive channel research has benefited from advances in electrophysiology, genomics and molecular genetics as well as from the application of biophysical techniques. Most recently, new analytical methods have been used to complement existing knowledge and generate insights into the molecular interactions that take place between mechanosensitive channel proteins and the surrounding membrane lipids. This article reviews the latest developments. 相似文献