Experimental study of the spray characteristics of biodiesel based on inedible oil

We studied the spray characteristics of inedible oil using experimental and simulation methods. Spray penetration, spray cone angle and spray tip speed were measured at different biodiesel ratios in a constant volume vessel with wide visualization and high back pressure, using a high-speed camera. The characteristics of biodiesel spray were simulated under the same conditions using Star-CD software. The experimental results showed that, as the ratio of biodiesel in the blends increased, spray penetration and spray speed increased, but the spray cone angle decreased. Throughout the spray injection period, the region at 0.05–0.475S (spray tip penetration) was a key area affecting spray cone angle. From 0.8 ms after injection, the spray penetration deviation ratios started to increase with increasing biodiesel blend ratios. Simulation results showed similar macroscopic spray characteristics to the experimental results for jatropha oil. The results also showed that the Sauter mean diameter of blend fuels was greater than that of diesel, and spray was more concentrated, due to the higher viscosity and surface tension of the biodiesel, compared with conventional diesel fuel. The macroscopic and microscopic spray properties of blended fuels containing 5%, 10% and 20% biodiesel were similar to diesel.     

Role of ICAM-1 in antigen presentation demonstrated by ICAM-1 defective mutants

We report a methodology for selecting APC with mutations that have impaired their ability to present Ag to T cells. A20 B lymphoblastoid cells were mutagenized and then repeatedly cocultured with murine T-T hybridomas in the presence of specific Ag. During these cocultures, the T-T hybridomas kill the competent APC, allowing the outgrowth of inactive variants. Two variants, A20.M1 and A20.M2, were isolated and studied in detail. These variants are impaired in their ability to present multiple Ag to T cells. This defect is also observed for the presentation of processing independent peptides by fixed APC indicating that a lesion exists in a post-Ag processing step. The level of expression of MHC molecules is unaffected and the functional defect in the APC is not localized to a particular MHC molecule. In contrast, these mutants were found to have a selective decrease in the expression of the murine homolog of ICAM-1, and the residual ability of these cells to present Ag was not blocked by anti-ICAM-1 mAb. Conversely, Ag presentation by the wild-type A20 is inhibited by anti-ICAM-1 mAb. Similarly, anti-LFA-1 mAb inhibited the response of T cells to Ag presented by the wild-type A20 to a much greater degree than by the mutant cells, indicating that LFA-1 is involved in interaction of T cells with the former, but not latter, APC. In the apparent absence of a contribution of LFA-1 to the T cell-APC interaction, either as a result of mAb blocking or the disruption of the APC membrane, the mutant and wild-type APC have a similar level of Ag-presenting activity. Reconstitution of ICAM-1 expression in these mutants by transfection with murine ICAM-1 cDNA fully restores their ability to present Ag. Together these results demonstrate that a murine ICAM-1 homolog is expressed on A20 B cells, where it functions as a major cell interaction molecule. The degree of functional impairment in these mutant APC gives insight into the contribution of cell interaction molecules to efficient Ag presentation and T cell-B cell interaction. Finally, these results also demonstrate the feasibility of selecting APC with mutations affecting Ag presentation.     

Heparin requirement for the quantitation of fibrinogen production by primary hepatocyte cultures

We have reported a rapid method for the quantitation of proteins secreted in culture media ([12.]). Using the same method, we observe that serum-free rat hepatocyte cultures exhibited a 100% increase in detectable secreted fibrinogen-antigen in the presence of 1 unit/ml heparin or greater at 24 h of culture. The amount of transferrin, haptoglobin, and albumin detected was unaltered by the presence of heparin. Since heparin is known to affect certain cellular functions, the fates of [³⁵S]methonine-labeled fibrinogen in cell extracts and culture media were examined employing pulse-chase experiments. Labeled intracellular fibrinogen disappeared at similar rates and was initially released into the media in similar amounts in the presence or absence of heparin. At 8 h during the chase, there was a 40–50% reduction in fibrinogen-antigen in spent culture medium lacking heparin. The presence of heparin did not alter the proteolytic degradation of secreted fibrinogen as determined by immunoblotting of spent culture media proteins separated by polyacrylamide gel electrophoresis. In vitro experiments indicate that clotting of fibrinogen by thrombin reduces the amount of immunodetectable fibrinogen. The results indicate that heparin increases the amount of detectable fibrinogen secreted by cultured hepatocytes by preventing clotting and not by stimulating synthesis or secretion or by inhibiting degradation. Hence, it is critically important to include heparin when secreted fibrinogen is quantitated by the method that we have developed.     

Casein kinase II phosphorylates the eukaryote-specific C-terminal domain of topoisomerase II in vivo.

The decatenation activity of DNA topoisomerase II is essential for viability as eukaryotic cells traverse mitosis. Phosphorylation has been shown to stimulate topoisomerase II activity in vitro. Here we show that topoisomerase II is a phosphoprotein in yeast and that the level of incorporated phosphate is significantly higher at mitosis than in G1. Comparison of tryptic phosphopeptide maps reveals that the major phosphorylation sites in vivo are targets for casein kinase II. Incorporation of phosphate into topoisomerase II is nearly undetectable at the non-permissive temperature in a conditional casein kinase II mutant. The sites modified by casein kinase II are located in the extreme C-terminal domain of topoisomerase II. This domain is absent in prokaryotic and highly divergent among eukaryotic type II topoisomerases, and may serve to regulate functions of topoisomerase II that are unique to eukaryotic cells.     

中国人红细胞PGM(PGM位点1)多态性的等电聚焦电泳研究

用等电聚焦电泳技术对北京地区180人进行红细胞葡萄糖磷酸变位酶(PGM_1)遗传表型的分析鉴定。共检测出九个PGM_1亚型,可能由于检测样本数还不够多,目前尚未检测到PGM_1 2-亚型。根据测定结果,观察了我国人群中PGM_1亚型的分布情况,并计算出决定PGM_1亚型的四个等位基因频率为:PGM~(1+)_10617,PGM~(1-)_1 0.100,PGM~(2+)_1 0.236,PGM~(2-)_10.047。采用等电聚焦电泳可将PGM_1的个体识别能力(DP值)由用普通淀粉胶电泳分型的0.558提高到0.742。结果与世界上其他国家和地区人群相似,PGM_1在我国人群中同样是一个个体识别能力很高的多态性酶类。     

Profiling the interactome of protein kinase C ζ by proteomics and bioinformatics

Background

Protein kinase C ζ (PKCζ), an isoform of the atypical protein kinase C, is a pivotal regulator in cancer. However, the molecular and cellular mechanisms whereby PKCζ regulates tumorigenesis and metastasis are still not fully understood. In this study, proteomics and bioinformatics analyses were performed to establish a protein-protein interaction (PPI) network associated with PKCζ, laying a stepping stone to further understand the diverse biological roles of PKCζ.

Methods

Protein complexes associated with PKCζ were purified by co-immunoprecipitation from breast cancer cell MDA-MB-231 and identified by LC-MS/MS. Two biological replicates and two technical replicates were analyzed. The observed proteins were filtered using the CRAPome database to eliminate the potential false positives. The proteomics identification results were combined with PPI database search to construct the interactome network. Gene ontology (GO) and pathway analysis were performed by PANTHER database and DAVID. Next, the interaction between PKCζ and protein phosphatase 2 catalytic subunit alpha (PPP2CA) was validated by co-immunoprecipitation, Western blotting and immunofluorescence. Furthermore, the TCGA database and the COSMIC database were used to analyze the expressions of these two proteins in clinical samples.

Results

The PKCζ centered PPI network containing 178 nodes and 1225 connections was built. Network analysis showed that the identified proteins were significantly associated with several key signaling pathways regulating cancer related cellular processes.

Conclusions

Through combining the proteomics and bioinformatics analyses, a PKCζ centered PPI network was constructed, providing a more complete picture regarding the biological roles of PKCζ in both cancer regulation and other aspects of cellular biology.

     

Utilization of Organic Liquid Fertilizer in Microalgae Cultivation for Biodiesel Production

The utilization of organic liquid fertilizer PAL-1 as the culture medium of the microalga Chlorella vulgaris was investigated for the purpose of biodiesel production. Cell growth and lipid accumulation in PAL-1 were evaluated and compared with those in the artificial medium BG-11. Cells showed mixotrophic growth when utilizing the organic liquid fertilizer PAL-1. The rates of cell growth (0.143 d^-1) and N consumption (14.9 mg/L/d) in PAL-1 were almost the same as those in BG-11, under the presence of 2% CO₂-enriched aeration and light irradiation. Lipid synthesis was triggered in PAL-1 on day 4, when nitrogen was completely consumed, and the lipid content reached up to 48% thereafter. Lipid productivity could be enhanced using repeated-batch cultivation in which cells were exposed to N limitation repeatedly, and thus lipid synthesis was induced while maintaining a sufficiently high cell density.     

Histopathological Features and Viral Antigen Distribution in the Lung of Fatal Patients with <Emphasis Type="Italic">Enterovirus</Emphasis> 71 Infection

Enterovirus 71 (EV71) infection causes hand-foot-and-mouth disease (HFMD) in children and might be accompanied by severe neurological complications. It has become one of the most important pathogens of central nervous system infection. To explore the causes of lung injury by EV71, the distribution of EV71 receptors, SCARB2 and PSGL-1, in human lung tissues was examined. Our results revealed that SCARB2 was positively distributed in the bronchial and bronchiolar epithelial cells, alveolar cells and macrophages, while PSGL-1 was positively scattered in bronchial and bronchiolar epithelial cells and macrophages, and negatively distributed in alveolar cells. The pathological changes of fatal lung with EV71 infection demonstrated intrapulmonary bronchitis and bronchiolitis, diffuse or focal infiltration of inflammatory cells, such as T cells and B cells in the wall and surrounding tissues, widened alveolar septum, capillaries in the septum with highly dilated and congested, and infiltrated inflammatory cells, showing different degrees of protein edema with fibrin exudation in the alveolar cavity, as well as obvious hyaline membrane formation in some alveolar cavities. The EV71 antigen in lung tissues was detected, and the viral antigen was positive in lung bronchial and bronchiolar epithelial cells, and positively scattered in the alveolar cells and macrophages. Therefore, in addition to the complications of central nervous system injury, the lung remains the main target organ for virus attack in severe EV71 infected patients. Lung injury was mainly caused by neurogenic damage and/or direct invasion of the virus into the lungs in critically serious children, and the lesions were mainly pulmonary edema and interstitial pneumonia.     

Selectively screen the antibacterial peptide from the hydrolysates of highland barley

Highland barley is one of the most important industrial crops in Tibetan plateau. Previous research indicated that highland barley has many medical functions. In this work, the antibacterial abilities of highland barley were investigated. The protein solutions hydrolyzed by trypsin for 4 h exhibited the highest antibacterial activity. An antibacterial peptide, barleycin, was screened and purified by magnetic liposome extraction combining with the protein profiles of reversed‐phase high‐performance liquid chromatography (RP‐HPLC). Structure, characterization, and safety evaluation of barleycin were further investigated. Amino acids sequence was determined as Lys‐Ile‐Ile‐Ile‐Pro‐Pro‐Leu‐Phe‐His by N‐sequencing. Circular dichroism spectra indicated the a‐helix conformation of barleycin. The activity spectrum included Bacillus subtilis, Staphylcoccus aureus, Listeria innocua and Escherichia coli and the MICs were from 4 to 16 μg/mL. Safety evaluations with cytotoxicity and hemolytic suggested this antibacterial peptide could be considered as safe at MICs. Finally, mode of action of barleycin on sensitive cells was primarily studied. The results suggested the damage of cell membrane.