Arabidopsis EPSIN1 plays an important role in vacuolar trafficking of soluble cargo proteins in plant cells via interactions with clathrin, AP-1, VTI11, and VSR1

Epsin and related proteins play important roles in various steps of protein trafficking in animal and yeast cells. Many epsin homologs have been identified in plant cells from analysis of genome sequences. However, their roles have not been elucidated. Here, we investigate the expression, localization, and biological role in protein trafficking of an epsin homolog, Arabidopsis thaliana EPSIN1, which is expressed in most tissues we examined. In the cell, one pool of EPSIN1 is associated with actin filaments, producing a network pattern, and a second pool localizes primarily to the Golgi complex with a minor portion to the prevacuolar compartment, producing a punctate staining pattern. Protein pull-down and coimmunoprecipitation experiments reveal that Arabidopsis EPSIN1 interacts with clathrin, VTI11, gamma-adaptin-related protein (gamma-ADR), and vacuolar sorting receptor1 (VSR1). In addition, EPSIN1 colocalizes with clathrin and VTI11. The epsin1 mutant, which has a T-DNA insertion in EPSIN1, displays a defect in the vacuolar trafficking of sporamin:green fluorescent protein (GFP), but not in the secretion of invertase:GFP into the medium. Stably expressed HA:EPSIN1 complements this trafficking defect. Based on these data, we propose that EPSIN1 plays an important role in the vacuolar trafficking of soluble proteins at the trans-Golgi network via its interaction with gamma-ADR, VTI11, VSR1, and clathrin.     

Secondary Structural Transformation of Bovine Lactoferricin Affects Its Antibacterial Activity

Probiotics and Antimicrobial Proteins - Lactoferricin (Lfcin) is a potent antibacterial peptide derived from lactoferrin by pepsin hydrolysis. It was hypothesized that structural transformation of...     

Microbiological and production characteristics of the Dagang high-temperature heavy oil reservoir (block no. 1) during trials of the biotechnology for enhanced oil recovery

Microbiological and biogeochemical data on the Kongdian bed (block no. 1) of the Dagang high-temperature oilfield during trials of the biotechnology for enhanced oil recovery are reported. Oil-bearing horizons of block no. 1 are characterized by high temperature (56.9–58.4°C), complex geological conditions, and heavy oil (density 0.966–0.969 g/cm³). The biotechnology implied injecting oxygen as an air-water mixture or H₂O₂ together with aqueous solution of nitrogen and phosphorus mineral salts through injection wells in order to activate the oilfield microbial community. In the course of trials, an increase in abundance of aerobic and anaerobic microorganisms was revealed, as well as increased methanogenesis rate in formation water. Microbial oxidation of heavy oil resulted in increased concentration of mineral carbonates dissolved in formation water, changes in the stable carbon isotopic composition δ¹³C/Σ(CO₂ + HCO₃ ^- + CO₃ ^2-), formation of biosurfactants, and decreased interfacial tension of formation water. Application of the biotechnology at the Kongdian bed (block no. 1) resulted in additional recovery of 6331 t oil. Oil viscosity in the zone of production wells located at the North block of the Kongdian bed decreased by 11%. A total of 46152 t additional oil was recovered at three experimental sites of the Dagang oilfield (North block and block no. 1 of the Kongdian bed and the Gangxi bed), which is an indication of high efficiency of the technology for activation of the oilfield microflora for heavy oil replacement from high-temperature oilfields.     

External Noise and External Signal Induced Transition of Gene Switch and Coherence Resonance in the Genetic Regulatory System

The transition of gene switch induced by external noises (multiplicative external noise and additive external noise) and external signals is investigated in the genetic regulatory system. Results show that the state-to-state transition of gene switch as well as resonant behaviors, such as the explicit coherence resonance (ECR), implicit coherence resonance (ICR) and control parameter coherence biresonance (CPCBR), can appear when noises are injected into the genetic regulatory system. The ECR is increased with the increase of the control parameter value when starting from the supercritical Hopf bifurcation parameter point, and there exists a critical control parameter value for the occurrence of ECR. However, the ICR is decreased as the control parameter value is increased when starting from the subcritical Hopf bifurcation point. In particular, the coherence of ECR is higher and more sensitive to noise than that of ICR. When an external signal is introduced into the system, the enhancement or suppression of the CPCBR and the number of peaks strongly depend on the frequency and amplitude of the external signal. Furthermore, the gene regulation system can selectively enhance or decrease the noise-induced oscillation signals at preferred frequency and amplitude of an external signal.     

一种新型的重组单链三特异抗体的构建与表达

双特异抗体由于其缺乏共刺激信号 ,激活的T细胞往往会导致凋亡。为了更有效地杀伤肿瘤细胞 ,构建了抗卵巢癌单链×抗CD3单链×抗CD2 8单域重组三特异抗体的表达载体。利用大肠杆菌中的分子伴侣FkpA与三特异抗体共表达 ,提高了三特异抗体的在BL2 1Star菌中的可溶性原核表达。ELISA结果显示 ,可溶性的重组单链三特异抗体 (sTRI)与SK OV 3细胞的膜抗原 ,Jurkat细胞上的CD3分子以及重组CD2 8抗原均有较强的结合活性。桥连试验证明该抗体能同时与SK OV 3细胞和Jurkat细胞结合。体外杀伤试验表明该抗体能激活外周血T细胞来杀伤肿瘤细胞。形态学观察也进一步说明该抗体具有良好的结合活性以及体外杀伤活性。这种新型的重组单链三特异抗体为基于T细胞的癌症免疫治疗建立了一个新的技术平台。     

Microbial transformation of ginsenoside Rb1 by Rhizopus stolonifer and Curvularia lunata

Of 49 microbial strains screened for their capabilities to transform ginsenoside Rb₁, Rhizopus stolonifer and Curvularia lunata produced four key metabolites: 3-O-[-d-glucopyranosyl-(1,2)--d-glucopyranosyl]- 20-O-[-d-glucopyranosyl]-3,12, 20(S)-trihydroxydammar-24-ene (1), 3-O-[-d-glucopyranosyl-(1,2)--d- glucopyranosyl]-20-O-[-d-glucopyranosyl]-3,12, 20(S)-trihydroxydammar-24-ol (2), 3-O-[-d-gluco- pyranosyl-(1,2)--d-glucopyranosyl]-3, 12, 20(S)-trihydroxydammar-24-ene (3), and 3-O--d-glucopyranosyl-3, 12, 20(S)-trihydroxydammar-24-ene (4), identified by TOF-MS, ¹H- and ¹³C-NMR spectral data. Metabolites 1, 3 and 4 were from the incubation with R. stolonifer, and 1 and 2 from the incubation with C. lunata. Compound 2 was identified as a new compound.     

A subset of chaperones and folding enzymes form multiprotein complexes in endoplasmic reticulum to bind nascent proteins

We demonstrate the existence of a large endoplasmic reticulum (ER)-localized multiprotein complex that is comprised of the molecular chaperones BiP; GRP94; CaBP1; protein disulfide isomerase (PDI); ERdj3, a recently identified ER Hsp40 cochaperone; cyclophilin B; ERp72; GRP170; UDP-glucosyltransferase; and SDF2-L1. This complex is associated with unassembled, incompletely folded immunoglobulin heavy chains. Except for ERdj3, and to a lesser extent PDI, this complex also forms in the absence of nascent protein synthesis and is found in a variety of cell types. Cross-linking studies reveal that the majority of these chaperones are included in the complex. Our data suggest that this subset of ER chaperones forms an ER network that can bind to unfolded protein substrates instead of existing as free pools that assembled onto substrate proteins. It is noticeable that most of the components of the calnexin/calreticulin system, which include some of the most abundant chaperones inside the ER, are either not detected in this complex or only very poorly represented. This study demonstrates an organization of ER chaperones and folding enzymes that has not been previously appreciated and suggests a spatial separation of the two chaperone systems that may account for the temporal interactions observed in other studies.