Enhanced production of total flavones from Inonotus baumii by multiple strategies

As one kind of important secondary metabolites produced by Inonotus baumii, flavones can be applied in food, medicine, and other industries due to their biological activities such as antioxidant, anticancer, and antibacterial activity. To enhance total flavone production in submerged fermentation of I. baumii, three different strategies, optimization of fermentation parameters by statistical designs including Plackett–Burman design and response surface methodology, addition of precursors and elicitors, and two-phase culture, were used. The production of total flavones (PTF) reached 1532.83?mg/L when the optimized medium was used. All precursors and elicitors can increase the PTF. The maximum PTF (2184.06?mg/L, up to 1.57-fold) was obtained with the addition of both AgNO₃ and glutathione in fermentation media. Interestingly, when 0.5% (w/v) DM130 macroporous resin as adsorbent was added to fermentation broth on day 4 of culture, the highest production reached 2407.79?mg/L with this two-phase culture strategy. These methods can be further applied to large-scale industrial production and broaden the application of flavones.     

Color vision models: Some simulations,a general n‐dimensional model,and the colourvision R package

The development of color vision models has allowed the appraisal of color vision independent of the human experience. These models are now widely used in ecology and evolution studies. However, in common scenarios of color measurement, color vision models may generate spurious results. Here I present a guide to color vision modeling (Chittka (1992, Journal of Comparative Physiology A, 170, 545) color hexagon, Endler & Mielke (2005, Journal Of The Linnean Society, 86, 405) model, and the linear and log‐linear receptor noise limited models (Vorobyev & Osorio 1998, Proceedings of the Royal Society B, 265, 351; Vorobyev et al. 1998, Journal of Comparative Physiology A, 183, 621)) using a series of simulations, present a unified framework that extends and generalize current models, and provide an R package to facilitate the use of color vision models. When the specific requirements of each model are met, between‐model results are qualitatively and quantitatively similar. However, under many common scenarios of color measurements, models may generate spurious values. For instance, models that log‐transform data and use relative photoreceptor outputs are prone to generate spurious outputs when the stimulus photon catch is smaller than the background photon catch; and models may generate unrealistic predictions when the background is chromatic (e.g. leaf reflectance) and the stimulus is an achromatic low reflectance spectrum. Nonetheless, despite differences, all three models are founded on a similar set of assumptions. Based on that, I provide a new formulation that accommodates and extends models to any number of photoreceptor types, offers flexibility to build user‐defined models, and allows users to easily adjust chromaticity diagram sizes to account for changes when using different number of photoreceptors.     

One Dog,but Which Dog? How Researchers Guide Participants to Select Dogs in Surveys of Human–Dog Relationships

Surveys and questionnaires are regularly used in studies of human–animal relationships. However, little attention has been given to understanding how survey participants are provided with instructions for the selection of a single animal within a multi-pet household, let alone the implications for reporting and interpreting data. We reviewed the instructions for the selection of an individual animal in studies addressing emotional or psychological attachment between people and dogs. By searching multidisciplinary journals from the year 2000 onwards, we identified a total of 128 papers, of which 63 met the inclusion criteria. Where selection criteria/instructions were not clear, authors were contacted. One in five studies (21%, or n = 13) did not report their instructions. When provided, instructions varied considerably. The most commonly provided direction was “favorite/closest relationship” (n = 12, or 19%). The remainder (n = 38, or 60%) were spread across eight different categories. Around half of the studies used a validated questionnaire that already contained an instruction, though a similar proportion of studies implemented author-designed instruments. Overall, the common absence and inconsistency of instructions for individual dog selection is taken to imply that there is no standard expectation or approach for instructions to be reported in studies of human relationships with dogs, or human–animal relationships more generally. We recommend further research on the implication of selection methods to ensure that instructions can be matched with specific research aims.     

Identification and quantification of blood–brain barrier transporters in isolated rat brain microvessels

The blood–brain barrier (BBB ) maintains brain homeostasis by tightly regulating the exchange of molecules with systemic circulation. It consists primarily of microvascular endothelial cells surrounded by astrocytic endfeet, pericytes, and microglia. Understanding the make‐up of transporters in rat BBB is essential to the translation of pharmacological and toxicological observations into humans. In this study, experimental workflows are presented in which the optimization of (a) isolation of rat brain microvessels (b) enrichment of endothelial cells, and (c) extraction and digestion of proteins were evaluated, followed by identification and quantification of BBB proteins. Optimization of microvessel isolation was indicated by 15‐fold enrichment of endothelial cell marker Glut1 mRNA , whereas markers for other cell types were not enriched. Filter‐aided sample preparation was shown to be superior to in‐solution sample preparation (10251 peptides vs. 7533 peptides). Label‐free proteomics was used to identify nearly 2000 proteins and quantify 1276 proteins in isolated microvessels. A combination of targeted and global proteomics was adopted to measure protein abundance of 6 ATP‐binding cassette and 27 solute carrier transporters. Data analysis using proprietary Progenesis and open access MaxQuant software showed overall agreement; however, Abcb9 and Slc22a8 were quantified only by MaxQuant, whereas Abcc9 and Abcd3 were quantified only by Progenesis. Agreement between targeted and untargeted quantification was demonstrated for Abcb1 (19.7 ± 1.4 vs. 17.8 ± 2.3) and Abcc4 (2.2 ± 0.7 vs. 2.1 ± 0.4), respectively. Rigorous quantification of BBB proteins, as reported in this study, should assist with translational modeling efforts involving brain disposition of xenobiotics.

     

Preserving racial hierarchy amidst changing racial demographics: how neighbourhood racial preferences are changing while maintaining segregation

Despite long-term, documented declines in racialized attitudes, racial inequality persists. Scholars have theorized why this dissonance exists but few have empirically demonstrated how views can become more progressive while simultaneously maintaining inequality. The present study uses neighbourhood racial preferences and their influence on racial residential segregation to demonstrate how in a diversifying context residents can become more “accepting” while simultaneously maintaining the racial hierarchy, the opposite of what most of the literature currently assumes. Using data from three distinct sources in the United States, this research finds that U.S. residents are increasingly willing to live amidst diversity yet whites still concentrate in white neighbourhoods. In short, white Americans are more willing to live in diverse neighbourhoods than in the past, but they are not willing to desegregate. We argue this preserves racial inequality. We conclude with a discussion of our findings and their implications for future research and practice.     

A multi‐resolution model to capture both global fluctuations of an enzyme and molecular recognition in the ligand‐binding site

In multi‐resolution simulations, different system components are simultaneously modeled at different levels of resolution, these being smoothly coupled together. In the case of enzyme systems, computationally expensive atomistic detail is needed in the active site to capture the chemistry of ligand binding. Global properties of the rest of the protein also play an essential role, determining the structure and fluctuations of the binding site; however, these can be modeled on a coarser level. Similarly, in the most computationally efficient scheme only the solvent hydrating the active site requires atomistic detail. We present a methodology to couple atomistic and coarse‐grained protein models, while solvating the atomistic part of the protein in atomistic water. This allows a free choice of which protein and solvent degrees of freedom to include atomistically. This multi‐resolution methodology can successfully model stable ligand binding, and we further confirm its validity by exploring the reproduction of system properties relevant to enzymatic function. In addition to a computational speedup, such an approach can allow the identification of the essential degrees of freedom playing a role in a given process, potentially yielding new insights into biomolecular function. Proteins 2016; 84:1902–1913. © 2016 Wiley Periodicals, Inc.     

响应面-满意度函数优化重组大肠杆菌产NMN转移酶发酵条件

重组大肠杆菌Escherichaia coli能高效表达NMN转移酶,以此为出发菌株,以菌体生长量OD600和NMN转移酶的活力为响应值,对重组大肠杆菌产NMN转移酶的发酵条件进行优化.首先以Plackett-Burman实验设计优化筛选出3个主要影响因子:胰蛋白胨、甘油、MgSO4;随后以Box-Behnken中心组合设计建立上述3个因子对OD600和NMN转移酶活力水平的数学模型;最后通过满意度函数获得最佳发酵条件为:酵母粉30 g/L,胰蛋白胨10.5 g/L,甘油3.49 mL/L,MgSO40.45 g/L,K2 HPO440.5 g/L,KH2 PO46.0 g/L,NH4 Cl 1.5 g/L,NaCl 0.6 g/L,接种量1.5%,诱导时间12 h.在该优化条件下,菌体生长和产酶水平均获得了显著的提升.重组NMN转移酶的活力水平从8.85 U/mg提高到15.48 U/mg,菌体生长量OD600从4.85提高到6.01,提高幅度分别为74.92%和23.92%.     

Optimization and effect of dairy industrial waste as media components in the production of hyaluronic acid by Streptococcus thermophilus

Hyaluronic acid (HA) production using a dairy industrial waste is a more cost-efficient strategy than using an expensive synthetic medium. In this study, we investigated the production of HA using Streptococcus thermophilus under shake flask conditions using dairy industrial waste as nutritional supplements, namely whey permeate (WP) and whey protein hydrolysate (WPH). Preliminary screening using Plackett–Burman design exhibited WP, WPH, initial pH, and inoculum size as significant factors influencing HA titer. Response surface methodology design of four factors was formulated at three levels for enhanced production of HA. Shake flask HA fermentation by S. thermophilus was performed under global optimized process conditions and the optimal HA titer (342.93?mg?L^?1) corroborates with Box–Behnken design prediction. The molecular weight of HA was elucidated as 9.22–9.46?kDa. The ultralow-molecular weight HA reported in this study has a potential role in drug and gene delivery applications.