An enzymatic solid-phase method for trace iodination of proteins and peptides with 125-iodine.

Solid-phase methodology has previously been applied to labeling of proteins and peptide hormones used in immunoassay with the aid of enzyme sorbent. In this publication a method based on the use of a new carrier-copolymer of maleic anhydride and butanediol divinylether is introduced. As a model, bovine serum albumin (BSA) was labeled using three different procedures: Chemical, with chloramine-T as oxidizing agent: enzymatic, in a liquid phase with lactoperoxidase (LP) and horseradish peroxidase (HRP); and enzymatic, in a solid phase with maleic anhydride butanediol divinylether-copolymer as the carrier of lactoperoxidase and horseradish peroxidase.The lactoperoxidase-mediated iodinating activity in both the liquid and solid phases was similar (incorporating 47 and 39% for the total ¹²⁵iodine added, 1 $\text{mCi}\text{10 μ}\text{g BSA}$), while HRP was more efficient in a liquid (11%) than in a solid phase (3%).Although the specific activity of the BSA labeled with chloramine-T was highest, this ¹²⁵I-labeled BSA was badly degraded during iodination. However, in either liquid or solid phase enzymatic iodinations, no degradation of the protein could be observed.Peptide hormones, luteinizing hormone, follicle-stimulating hormone and angiotensin II, iodinated with lactoperoxidase or lactoperoxidase sorbent for radioimmunoassays reacted better than peptide hormones iodinated with chemical oxidants and remained unaltered during storage.     

人工湿地植物种类及多样性对甲烷释放及功能基因丰度的影响

为了研究人工湿地处理中碳/氮水平的废水时植物种类及多样性对系统甲烷释放及功能基因丰度的影响,我们构建了实验尺度的人工湿地微宇宙实验系统。选取千屈菜(Lythrum salicaria L.)和海寿花(Pontederia cordata L.)2种人工湿地常用、景观效果好的植物,在系统中配置了单种处理和两物种混种处理。结果表明:千屈菜与海寿花混种系统的甲烷释放强度(8.78 mg CH_4 m~(-2) d~(-1))高于两物种单种系统的平均值(6.97 mg CH_4 m~(-2) d~(-1))(P0.001),同甲烷释放一样,混种系统的mcrA基因绝对丰度(977541.6 copies/g dw soil)也高于两物种单种系统的平均值(585146.8 copies/g dw soil),但混种系统的pmoA基因绝对丰度(326956.6 copies/g dw soil)低于两物种单种系统的平均值(1043616.0 copies/g dw soil)(P0.001)。此外,混种系统的微生物量、植物生物量高于两物种单种系统的平均值(P0.01),但出水铵态氮浓度低于两物种单种系统的平均值(P0.05),出水总有机碳浓度和硝态氮浓度在单混种系统间无显著差异(P0.05)。千屈菜单种系统和海寿花单种系统间的甲烷释放强度、pmoA基因绝对丰度、微生物量、植物生物量和出水铵态氮浓度存在显著差异(P0.05),但mcrA基因绝对丰度、出水总有机碳和硝态氮浓度无显著差异(P0.05)。为了达到人工湿地的高净化效率,需要将千屈菜与海寿花混合种植,但混合种植强化甲烷释放。通过植物种类和丰富度对各指标变异的解释度(ω~2)分析发现,植物种类对甲烷释放、pmoA基因绝对丰度、出水铵态氮的影响大于植物丰富度,但对mcrA基因绝对丰度的影响小于植物丰富度。     

Effect of spatial connectivity on host resistance in a highly fragmented natural pathosystem

Both theory and experimental evolution studies predict migration to influence the outcome of antagonistic coevolution between hosts and their parasites, with higher migration rates leading to increased diversity and evolutionary potential. Migration rates are expected to vary in spatially structured natural pathosystems, yet how spatial structure generates variation in coevolutionary trajectories across populations occupying the same landscape has not been tested. Here, we studied the effect of spatial connectivity on host evolutionary potential in a natural pathosystem characterized by a stable Plantago lanceolata host network and a highly dynamic Podosphaera plantaginis parasite metapopulation. We designed a large inoculation experiment to test resistance of five isolated and five well‐connected host populations against sympatric and allopatric pathogen strains, over 4 years. Contrary to our expectations, we did not find consistently higher resistance against sympatric pathogen strains in the well‐connected populations. Instead, host local adaptation varied considerably among populations and through time with greater fluctuations observed in the well‐connected populations. Jointly, our results suggest that in populations where pathogens have successfully established, they have the upper hand in the coevolutionary arms race, but hosts may be better able to respond to pathogen‐imposed selection in the well‐connected than in the isolated populations. Hence, the ongoing and extensive fragmentation of natural habitats may increase vulnerability to diseases.     

Centrally Symmetric Focusing of Surface Plasmon Polaritons with a Rectangular Holes Arrayed Plasmonic Lens

Plasmonics - Nano rectangular holes etched in a gold thin film are optimized and arrayed to form a plasmonic lens. We demonstrate both theoretically and numerically that the proposed plasmonic lens...     

Mechanism of attenuation of protein loss in murine C2C12 myotubes by d-myo-inositol 1,2,6-triphosphate

d-Myo-inositol 1,2,6-triphosphate (alpha trinositol, AT) has been shown to attenuate muscle atrophy in a murine cachexia model through an increase in protein synthesis and a decrease in degradation. The mechanism of this effect has been investigated in murine myotubes using a range of catabolic stimuli, including proteolysis-inducing factor (PIF), angiotensin II (Ang II), lipopolysaccharide, and tumor necrosis factor-α/interferon-γ. At a concentration of 100 μM AT was found to attenuate both the induction of protein degradation and depression of protein synthesis in response to all stimuli. The effect on protein degradation was accompanied by attenuation of the increased expression and activity of the ubiquitin-proteasome pathway. This suggests that AT inhibits a signalling step common to all four agents. This target has been shown to be activation (autophosphorylation) of the dsRNA-dependent protein kinase (PKR) and the subsequent phosphorylation of eukaryotic initiation factor 2 on the α-subunit, together with downstream signalling pathways leading to protein degradation. AT also inhibited activation of caspase-3/-8, which is thought to lead to activation of PKR. The mechanism of this effect may be related to the ability of AT to chelate divalent metal ions, since the attenuation of the increased activity of the ubiquitin-proteasome pathway by PIF and Ang II, as well as the depression of protein synthesis by PIF, were reversed by increasing concentrations of Zn²⁺. The ability of AT to attenuate muscle atrophy by a range of stimuli suggests that it may be effective in several catabolic conditions.     

FBXO6介导的ERO1L泛素化降解对膀胱癌细胞增殖、迁移和侵袭的作用研究

目的探究F盒蛋白6 （FBXO6）对膀胱癌细胞的作用及其作用机制。 方法体外培养人正常膀胱上皮细胞株（SV-HUC-1）和人膀胱癌细胞株（T24）。用过表达载体阴性对照（oe-NC）、过表达FBXO6 （oe-FBXO6）、过表达内质网氧化还原蛋白-1样蛋白（oe-ERO1L）及oe-FBXO6和oe-ERO1L慢病毒液（MOI = 20）感染T24细胞。RT-qPCR检测细胞FBXO6和ERO1L mRNA表达;放线菌酮（CHX）蛋白合成抑制实验检测T24细胞ERO1L蛋白稳定性;免疫共沉淀（Co-IP）实验检测FBXO6对ERO1L泛素化调控;Western blot检测细胞FBXO6和ERO1L蛋白表达;CCK-8检测细胞活力;克隆形成实验检测细胞增殖;Transwell实验检测细胞迁移和侵袭。两组间比较采用独立样本t检验,多组间比较采用单因素方差分析,组间两两比较采用LSD-t检验。 结果与SV-HUC-1相比,T24细胞中FBXO6 mRNA （1.00±0.05比0.33±0.02）和蛋白表达（1.00±0.11比0.31±0.03）均降低（P均< 0.05）,而ERO1L mRNA （1.00±0.05比2.70±0.12）和蛋白表达（1.00±0.16比3.27±0.09）均升高（P均< 0.05）。FBXO6可降低ERO1L蛋白稳定性并促进ERO1L泛素化。与空白对照和oe-NC相比,oe-FBXO6细胞中FBXO6 mRNA （1.00±0.06比3.74±0.18）和蛋白表达（1.00±0.10比2.25±0.06）均升高,ERO1L蛋白表达（0.99±0.08比0.21±0.03）,细胞活力、克隆形成数[（78.00±3.00）比（41.67±2.52）个]、迁移[（150.67±5.03）比（91.67±5.51）个]和侵袭细胞数[（122.00±7.00）比（74.67±5.51）个]均降低（P均< 0.05）;与oe-NC相比,oe-ERO1L细胞中ERO1L蛋白表达（1.01±0.06比2.58±0.02）、细胞活力、克隆形成数[ （78.00±3.00）比（121.67±7.64）个]、迁移[（150.67±5.03）比（230.33±12.01）个]和侵袭细胞数[（122.00±7.00）比（203.00± 11.53）个]均升高（P均< 0.05）;与oe-FBXO6相比,oe-FBXO6+oe-ERO1L细胞中ERO1L蛋白表达（0.54±0.02比1.02±0.06）,细胞活力、克隆形成数[（41.67±2.52）比（62.00±3.61）个]、迁移[（91.67±5.51）比（131.67±6.03）个]和侵袭细胞数[（74.67±5.51）比（102.67±7.51）个]均升高（P均< 0.05）。 结论FBXO6通过介导ERO1L泛素化降解抑制膀胱癌细胞增殖、迁移和侵袭。     

Priming nonlinear searches for pathway identification

Background  

Dense time series of metabolite concentrations or of the expression patterns of proteins may be available in the near future as a result of the rapid development of novel, high-throughput experimental techniques. Such time series implicitly contain valuable information about the connectivity and regulatory structure of the underlying metabolic or proteomic networks. The extraction of this information is a challenging task because it usually requires nonlinear estimation methods that involve iterative search algorithms. Priming these algorithms with high-quality initial guesses can greatly accelerate the search process. In this article, we propose to obtain such guesses by preprocessing the temporal profile data and fitting them preliminarily by multivariate linear regression.     

Chromosome‐level assembly of wild Bactrian camel genome reveals organization of immune gene loci

Camelids are characterized by their unique adaptive immune system that exhibits the generation of homodimeric heavy‐chain immunoglobulins, somatic hypermutation of T‐cell receptors, and low genetic diversity of major histocompatibility complex (MHC) genes. However, short‐read assemblies are typically highly fragmented in these gene loci owing to their repetitive and polymorphic nature. Here, we constructed a chromosome‐level assembly of wild Bactrian camel genome based on high‐coverage long‐read sequencing and chromatin interaction mapping. The assembly with a contig N50 of 5.37 Mb and a scaffold N50 of 76.03 Mb, represents the most contiguous camelid genome to date. The genomic organization of immunoglobulin heavy‐chain locus was similar between the wild Bactrian camel and alpaca, and genes encoding for conventional and heavy‐chain antibodies were intermixed. The organizations of two immunoglobulin light‐chain loci and four T cell receptor loci were also fully deciphered using the new assembly. Additionally, the complete classical MHC region was resolved into a single contig. The high‐quality assembly presented here provides an essential reference for future investigations examining the camelid immune system.