Proteomics Approach (iTRAQ) to Test Subchronic and Chronic Toxicity Effects of Mice Exposed to Drinking Water Source from Yangtze River Delta

Objective: To investigate the combined effects of the pollutants in source of drinking water for local populations, mice models were used to test the subchronic toxicity for three months and chronic toxicity for six months. Methods and Results: By using proteomics approach (iTRAQ), we had identified 29 differentially expressed proteins, which were related to amino acids metabolism, cell skeleton reorganization, apoptosis and cancer genesis. Moreover, 12 out of these 29 identified proteins are located in mitochondria, indicating drinking water source from Yangtze River Delta may exert oxidative damage stress to liver cells. All these cellular processes had been verified by hepatic histopathology, real time-PCR, flow cytometry test and our previous metabolic profile results. Conclusion: All these tests indicated that drinking water source from Yangtze River Delta could accelerate aging, enhance apoptosis and carcinogenesis risk.

Characterizing mechanics of membrane tether from relaxation curve obtained by optical tweezers

Optical tweezers is a powerful tool in the study of membrane tension. Comparing to pulling out an entire membrane tether at one time, the step-like method is more efficient because multiple relaxation curves can be obtained from one membrane tether. However, there is few proper models that describe relaxation curves to characterize mechanical properties of cell membrane. Here we established a model to describe the relaxation curve of HeLa cells based on the relationship between membrane tether diameter and tensions. We obtained effective viscosities and static tensions by fitting relaxation curves to our model. We noticed the delicate structure of relaxation curves contains information of cell skeleton changes and protein diffusion. Our study paved a novel pathway to characterize the dynamics and mechanics of cell membrane.

Phosphoproteomic Analysis of Spiroplasma eriocheiris and Crosstalk with Acetylome Reveals the Role of Post-Translational Modifications in Metabolism

Background: Post-translational modifications (PTMs) such as phosphorylation are an essential regulatory mechanism of protein function and associated with a range of biological processes beyond genome and transcriptome. Spiroplasma eriocheiris, a wall-less helical bacterium, is one of the smallest known self-replicating bacteria and a novel pathogen of freshwater crustacean. Methods: To study the physiological characteristics and regulatory mechanism of S. eriocheiris, the protein phosphorylation in the bacterium were systematically investigated by iTRAQ analyzed by LC-MS/MS. Data are available via ProteomeXchange with identifier PXD015055. Results: We identified 465 phosphorylation sites in 246 proteins involved in a broad spectrum of fundamental biological process ranging from regulation of metabolic pathways to protein synthesis. Notably, most proteins in glycolysis and all proteins in the arginine deiminase system were phosphorylated. Meanwhile, the cytoskeleton proteins (Fibril, Mrebs and ET-Tu) were all phosphorylated suggest that the phosphorylation also may play a crucial role in cell skeleton formation. We have got a lot of highly conserved proteins and phosphorylation sites by analysis, and those proteins or phosphorylation sites were mainly participated in glucose metabolism and protein synthesis. Crosstalk analysis with protein-protein interaction networks in relation to phosphorylated proteins and acetylated proteins found that the two PTMs are required for playing crucial roles in many physiological processes in S. eriocheiris. By comparing the relative positions of acetylation versus phosphorylation, we found that the two modifications often found close to proximity on the same protein. Conclusions: The results imply that there is previously unreported hidden role of phosphorylation that define the functional state of Spiroplasma.

Effects of Cyclic Tensile Strain on Oxidative Stress and the Function of Schwann Cells

Schwann cells (SCs) are significant due to the way in which they sustain and myelinate axons within the peripheral nervous system (PNS). This study has investigated the effect of cyclic tensile strain (CTS) on the oxidative stress and function of SCs derived from the sciatic nerves of an infant rat population. A group of 20 6-day-old Wistar rats was selected, and SCs were separated from the sciatic nerve. The SCs then underwent a 6-hour period of cyclical straining, and ElectroForce 3200 in combination with the BioDynamic chamber was employed to apply 0% and 5% strains at a 0.25 Hz frequency. The results showed that the control group suffered higher oxidative stress than that in 5% strains group (P<0.05). The results RT-PCR analysis indicated a correlation between 5% CTS and a reduction in Netrin-1 expression (P<0.05). Furthermore, there was a significant upregulation in NGF, GDNF, and Slit-2 gene expression (P<0.05). Finally, the results showed that CTS stimulate SCs by increasing the expression of nerve-oriented factors, and these importantly caused the decrease of oxidative stress, reconstruction of cell skeleton, the promotion of axonal regrowth, and the augmentation of nerves.

Systematic Study on Morphology of Anodic Alumina Produced by Hard Anodization in the Electrolytes Modified with Ethylene Glycol

The morphology of anodic aluminum oxide (AAO) produced by hard anodization (HA) in oxalic acid electrolyte modified with various amount of ethylene glycol (EG) was investigated. The EG induces a considerable changes in the AAO morphology. The AAO transforms from continuous nanoporous film to separated AAO nanotubes upon addition of increasing amount of EG. In the sample II (4:1 v/v water to EG mixture) well separated nanotubes with variable wall thickness are produced. In the sample III (1:1 v/v water to EG solution) the nanotubes “imprisoned” in a partially dissolved cell skeleton with regularly spaced apertures along the cell are formed. In the electrolyte with the highest amount of EG (1:4 v/v water to EG mixture) an irregular AAO consisted of formless oxide and the oxide in a form of separated tubes of thick walls and small pores is fabricated. Based on the data obtained in this work it is concluded that the C containing ionic species originating from the EG dissociation along with the high electric field (E) operating during the HA were responsible for the separation phenomena. These ions, driven by the high E, were transported from the electrolyte to the pore base, where they were being embedded into the AAO framework generating strong mechanical stresses at cell boundaries and initiating the cell cleavage process. Moreover, some of these charged particles were ionized under the high E providing additional electrons to the overall current flow and giving rise to a sudden current density boost in the samples II and III.

Anatomy of the red cell membrane skeleton: unanswered questions

The red cell membrane skeleton is a pseudohexagonal meshwork of spectrin, actin, protein 4.1R, ankyrin, and actin-associated proteins that laminates the inner membrane surface and attaches to the overlying lipid bilayer via band 3–containing multiprotein complexes at the ankyrin- and actin-binding ends of spectrin. The membrane skeleton strengthens the lipid bilayer and endows the membrane with the durability and flexibility to survive in the circulation. In the 36 years since the first primitive model of the red cell skeleton was proposed, many additional proteins have been discovered, and their structures and interactions have been defined. However, almost nothing is known of the skeleton’s physiology, and myriad questions about its structure remain, including questions concerning the structure of spectrin in situ, the way spectrin and other proteins bind to actin, how the membrane is assembled, the dynamics of the skeleton when the membrane is deformed or perturbed by parasites, the role lipids play, and variations in membrane structure in unique regions like lipid rafts. This knowledge is important because the red cell membrane skeleton is the model for spectrin-based membrane skeletons in all cells, and because defects in the red cell membrane skeleton underlie multiple hemolytic anemias.

Identification of the proteome of the midgut of silkworm, Bombyx mori L., by multidimensional liquid chromatography (MDLC) LTQ-Orbitrap MS

The midgut is the digestive apparatus of the silkworm and its proteome was studied by using nano-LC (liquid chromatography) electrospray ionization MS/MS (tandem MS). MS data were analysed by using X!Tandem searching software using different parameters and validated by using the Poisson model. A total of 90 proteins were identified and 79 proteins were described for the first time. Among the new proteins, (i) 22 proteins were closely related to the digestive function of the midgut, including 11 proteins of digestive enzymes secreted by the epithelium, eight proteins of intestine wall muscle and mechanical digestion and three proteins of peritrophic membrane that could prevent the epithelium from being mechanically rubbed; (ii) 44 proteins were involved in metabolism of substance and energy; and (iii) 11 proteins were associated with signal transduction, substance transport and cell skeleton.