Chronic hypoperfusion alters the content and structure of proteins and lipids of rat brain homogenates: a Fourier transform infrared spectroscopy study

Arteriovenous malformations (AVMs), masses of abnormal blood vessels which grow in the brain, produce high flow shunts that steal blood from surrounding brain tissue, which is chronically hypoperfused. Hypoperfusion is a condition of inadequate tissue perfusion and oxygenation, resulting in abnormal tissue metabolism. Fourier transform infrared (FTIR) spectroscopy is used in this study to investigate the effect of hypoperfusion on homogenized rat brain samples at the molecular level. The results suggest that the lipid content increases, the protein content decreases, the lipid-to-protein ratio increases, and the state of order of the lipids increases in the hypoperfused brain samples. FTIR results also revealed that, owing to hypoperfusion, not only the protein synthesis but also the protein secondary structure profile is altered in favor of -sheets and random coils. These findings clearly demonstrate that, FTIR spectroscopy can be used to extract valuable information at the molecular level so as to have a better understanding of the effect of hypoperfusion on rat brain.     

Recombinant biosynthesis of bacterial cellulose in genetically modified Escherichia coli

Bioprocess and Biosystems Engineering - Bacterial cellulose (BC) exhibits unique properties such as high purity compared to plant-based cellulose; however, commercial production of BC has remained...     

The investigation of glutamate transporter 1 (GLT-1) degradation pathway in glioblastoma cells

Molecular Biology Reports - Glioblastoma multiform is a primary brain tumor derived from glial cells. The aim of this study is to investigate how glutamate metabolism is regulated by glutamate...     

The Effect of Cisplatin Toxicity and Capsaicin on Electron Transport Chain in Liver and Kidney of Sprague Dawley Rats

Cisplatin accumulates in mitochondria, which is a potent and widely used chemotherapeutic agent. In order to clarify the potential effect of cisplatin on electron transport chain (ETC), the variation of succinate dehydrogenase (SDH) and cytochrome c oxidase (COX) enzyme activities, nucleotide levels, as well as catalase (CAT) enzyme and membrane lipid peroxidation (LPO) level with respect to liver and kidney of cisplatin-exposed rats were studied. We found that cisplatin caused significant impairment in the SDH, COX, and CAT activities, and nucleotide levels associated with membrane LPO in isolated mitochondria. It was determined whether capsaicin, as an antioxidant, has a possible protective role on all investigated parameters of liver and kidney induced by cisplatin. The results of capsaicin + cisplatin suggest that capsaicin have antioxidant capacity to scavenge ROS to prevent membrane damage.     

Proteomic profiling of HBV infected liver biopsies with different fibrotic stages

Background

Hepatitis B virus (HBV) is a global health problem, and infected patients if left untreated may develop cirrhosis and eventually hepatocellular carcinoma. This study aims to enlighten pathways associated with HBV related liver fibrosis for delineation of potential new therapeutic targets and biomarkers.

Methods

Tissue samples from 47 HBV infected patients with different fibrotic stages (F1 to F6) were enrolled for 2D-DIGE proteomic screening. Differentially expressed proteins were identified by mass spectrometry and verified by western blotting. Functional proteomic associations were analyzed by EnrichNet application.

Results

Fibrotic stage variations were observed for apolipoprotein A1 (APOA1), pyruvate kinase PKM (KPYM), glyceraldehyde 3-phospahate dehydrogenase (GAPDH), glutamate dehydrogenase (DHE3), aldehyde dehydrogenase (ALDH2), alcohol dehydrogenase (ALDH1A1), transferrin (TRFE), peroxiredoxin 3 (PRDX3), phenazine biosynthesis-like domain-containing protein (PBLD), immuglobulin kappa chain C region (IGKC), annexin A4 (ANXA4), keratin 5 (KRT5). Enrichment analysis with Reactome and Kegg databases highlighted the possible involvement of platelet release, glycolysis and HDL mediated lipid transport pathways. Moreover, string analysis revealed that HIF-1α (Hypoxia-inducible factor 1-alpha), one of the interacting partners of HBx (Hepatitis B X protein), may play a role in the altered glycolytic response and oxidative stress observed in liver fibrosis.

Conclusions

To our knowledge, this is the first protomic research that studies HBV infected fibrotic human liver tissues to investigate alterations in protein levels and affected pathways among different fibrotic stages. Observed changes in the glycolytic pathway caused by HBx presence and therefore its interactions with HIF-1α can be a target pathway for novel therapeutic purposes.

     

Forecasting Social Unrest Using Activity Cascades

Social unrest is endemic in many societies, and recent news has drawn attention to happenings in Latin America, the Middle East, and Eastern Europe. Civilian populations mobilize, sometimes spontaneously and sometimes in an organized manner, to raise awareness of key issues or to demand changes in governing or other organizational structures. It is of key interest to social scientists and policy makers to forecast civil unrest using indicators observed on media such as Twitter, news, and blogs. We present an event forecasting model using a notion of activity cascades in Twitter (proposed by Gonzalez-Bailon et al., 2011) to predict the occurrence of protests in three countries of Latin America: Brazil, Mexico, and Venezuela. The basic assumption is that the emergence of a suitably detected activity cascade is a precursor or a surrogate to a real protest event that will happen “on the ground.” Our model supports the theoretical characterization of large cascades using spectral properties and uses properties of detected cascades to forecast events. Experimental results on many datasets, including the recent June 2013 protests in Brazil, demonstrate the effectiveness of our approach.