ABSTRACT
Quartz, a common inorganic nonmetallic mineral, is usually removed or purified by beneficiation, normally flotation. Given the strong polarity of the quartz surface, it is easy to hydrate to form a hydroxylation layer, which makes it impossible to float quartz with sodium oleate (OL) used alone. An ideal flotation method for quartz is preactivation with Ca2+, followed by collection with OL. Herein, the effects of surface hydroxylation on the adsorption of the anionic collector OL on the quartz surface before and after Ca2+ activation are systematically investigated by density functional theory (DFT) calculations. The results show that the displacement adsorption of surface hydroxyl substituted by OL- is not feasible in thermodynamics, and the OL- can only bind to the H atoms of the hydroxylated quartz surface via hydrogen bonds, namely, hydrogen binding adsorption. Due to the electrostatic repulsion and steric hindrance effect induced by the surface hydroxylation structure, the adsorption ability of OL- on the quartz surface mediated by hydroxyl bridges is very weak, which is insufficient to realize quartz floating. However, Ca2+ ions are easily adsorbed on the hydroxylated quartz surface, providing favorable active sites for subsequent adsorption of OL-, thus becoming a credible solution for the industrial flotation of the strong hydrophilic mineral quartz. These findings shed some new insights for accurately understanding the flotation mechanism of strongly hydrophilic oxide minerals and are beneficial to promoting the development of mineral flotation fundamentals.
ABSTRACT
Dodecylamine (DDA) and sodium oleate (OL) are commonly used collectors in the reverse flotation and the direct flotation of goethite. However, the flotation mechanisms of DDA and OL on the goethite surface remain unclear. In this study, the first-principles density functional theory calculations were used to reveal the role of the hydration of the goethite surface and its effects on flotation reagents from a microscopic perspective. The calculation results showed that DDA was adsorbed on the surface of goethite by hydrogen bonds in the absence of hydration. However, the existence of the hydration microstructure hindered the formation of hydrogen bonds and made it difficult for DDA to be adsorbed on the goethite surface. In the OL system, oleate ions are chemically adsorbed on the surface Fe sites of goethite in the absence of hydration, while in the presence of hydration, the oleate ions were adsorbed on the H-terminal hydration surface of goethite by hydrogen bonds. This work sheds new light on the roles of the hydration microstructure and the adsorption mechanism of the flotation reagent on the oxide minerals.
ABSTRACT
Surface coordination chemistry is important in areas such as adsorption, separation, and catalysts. In this work, surface coordination interactions of benzohydroxamic acid (BHA) with the lead ion [Pb(II)] adsorbed on the cassiterite surface have been investigated by first-principles calculations due to its great significance in froth flotation. Cluster calculations show that BHA possesses the weakest chelation with Pb(II) due to the electron withdrawal ability of the benzyl ring in comparison with other hydroxamic acids. Pb(II) thermodynamically prefers to react with the cassiterite surface rather than BHA. On the other hand, the partial density of states and the atomic overlap populations have consistently verified that the adsorption of BHA results in a better symmetry in electron densities than the hydrated Pb(II). The electron density maps and the electronic localization functions have further visualized the rearrangement of the 6s2 lone pair around the lead atom. It can be concluded that the surface coordination mechanisms of Pb(II) on oxide minerals can be attributed to the coordination ability of BHA and the unique electronic structure of Pb(II), which accounts for the reported better flotation performance of the pre-assemble strategy than the pre-activating approach. This work sheds some new light on the unique coordination activation mechanism of metal ions on oxide mineral surfaces. It should be instructive to design and screen new environment-friendly flotation reagents and flotation flowsheets.
ABSTRACT
Pseudorabies virus (PRV) UL2 (pUL2) is a multifunctional protein, which is homologous with herpes simplex virus 1 early protein UL2 (hUL2) and crucial for the viral propagation. Yet, how pUL2 executes its roles in the viral life cycle remain inadequately understood. In order to uncover its effect on the procedure of PRV infection, investigation was performed to examine the subcellular distribution of pUL2 and establish its trafficking mechanism. In the present study, enhanced yellow fluorescent protein or Myc tag fused pUL2 was transiently overexpressed in transfected cells and exhibited an absolutely nuclear accumulation without the existence of other PRV proteins. Additionally, the nuclear trafficking of pUL2 was proved to rely on Ran-, transportin-1, importin ß1, importin α1, α3 and α5. Accordingly, these data will benefit the knowledge of pUL2-mediated biological effects in PRV infection cycle.
Subject(s)
Cell Nucleus/metabolism , Uracil-DNA Glycosidase/metabolism , Viral Proteins/metabolism , Active Transport, Cell Nucleus , Animals , COS Cells , Chlorocebus aethiops , Cloning, Molecular , Uracil-DNA Glycosidase/genetics , Viral Proteins/geneticsABSTRACT
Epstein-Barr virus (EBV), a ubiquitous gammaherpesvirus, can regulate the antiviral response of NF-κB signaling, which is critical for cell survival, growth transformation, and virus latency. Here, we showed that tegument protein BGLF2 could inhibit TNF-α-induced NF-κB activity. BGLF2 was shown to interplay with the NF-κB subunits p65 and p50, and the Rel homology domain of p65 was the pivotal region to interact with BGLF2. Nonetheless, BGLF2 did not influence the development of p65-p50 dimerization. Yet, overexpression of BGLF2 inhibited the phosphorylation of p65 Ser536 (but not Ser276) and blocked the nuclear translocation of p65. In addition, knockdown of BGLF2 during EBV lytic replication elevated NF-κB activity and the phosphorylation of p65 Ser536. Taken together, these results suggest that the inhibition of NF-κB activation may serve as a strategy to escape the host's antiviral innate immunity to EBV during its lytic infection.-Chen, T., Wang, Y., Xu, Z., Zou, X., Wang, P., Ou, X., Li, Y., Peng, T., Chen, D., Li, M., Cai, M. Epstein-Barr virus tegument protein BGLF2 inhibits NF-κB activity by preventing p65 Ser536 phosphorylation.
Subject(s)
Cell Nucleus/metabolism , Epstein-Barr Virus Infections/metabolism , Herpesvirus 4, Human/physiology , NF-kappa B/antagonists & inhibitors , Transcription Factor RelA/metabolism , Viral Fusion Proteins/metabolism , Epstein-Barr Virus Infections/virology , HEK293 Cells , HeLa Cells , Humans , NF-kappa B/genetics , NF-kappa B/metabolism , Phosphorylation , Protein Transport , Signal Transduction , Transcription Factor RelA/genetics , Viral Fusion Proteins/geneticsABSTRACT
Our hypothesis is that hyaluronic acid may regulate the differentiation of human amniotic epithelial cells (hAECs) into insulin-producing cells and help the treatment of type 1 diabetes. Herein, a protocol for the stepwise in vitro differentiation of hAECs into functional insulin-producing cells was developed by mimicking the process of pancreas development. Treatment of hAECs with hyaluronic acid enhanced their differentiation of definitive endoderm and pancreatic progenitors. Endodermal markers Sox17 and Foxa2 and pancreatic progenitor markers Pax6, Nkx6.1, and Ngn3 were upregulated an enhanced gene expression in hAECs, but hAECs did not express the ß cell-specific transcription factor Pdx1. Interestingly, hyaluronic acid promoted the expression of major pancreatic development-related genes and proteins after combining with commonly used inducers of stem cells differentiation into insulin-producing cells. This indicated the potent synergistic effects of the combination on hAECs differentiation in vitro. By establishing a multiple injection transplantation strategy via tail vein injections, hAECs transplantation significantly reduced hyperglycemia symptoms, increased the plasma insulin content, and partially repaired the islet structure in type 1 diabetic mice. In particular, the combination of hAECs with hyaluronic acid exhibited a remarkable therapeutic effect compared to both the insulin group and the hAECs alone group. The hAECs' paracrine action and hyaluronic acid co-regulated the local immune response, improved the inflammatory microenvironment in the damaged pancreas of type 1 diabetic mice, and promoted the trans-differentiation of pancreatic α cells into ß cells. These findings suggest that hyaluronic acid is an efficient co-inducer of the differentiation of hAECs into functional insulin-producing cells, and hAECs treatment with hyaluronic acid may be a promising cell-replacement therapeutic approach for the treatment of type 1 diabetes.
Subject(s)
Amnion/drug effects , Cell Differentiation/drug effects , Diabetes Mellitus, Experimental/therapy , Epithelial Cells/drug effects , Hyaluronic Acid/pharmacology , Activins/metabolism , Amnion/metabolism , Animals , Cell Culture Techniques/methods , Cell- and Tissue-Based Therapy/methods , Cells, Cultured , Disease Models, Animal , Embryonic Stem Cells/drug effects , Embryonic Stem Cells/metabolism , Endoderm/drug effects , Endoderm/metabolism , Epithelial Cells/metabolism , Humans , Inflammation/metabolism , Insulin/metabolism , Insulin-Secreting Cells/drug effects , Insulin-Secreting Cells/metabolism , Male , Mice , Pancreas/drug effects , Pancreas/metabolismABSTRACT
Pseudorabies virus (PRV) early protein EP0 is a homologue of the herpes simplex virus 1 (HSV-1) immediate-early protein ICP0, which is a multifunctional protein and important for HSV-1 infection. However, the definite function of EP0 during PRV infection is not clear. In this study, to determine if EP0 might localize to the nucleus, as it is shown for its homologue in HSV-1, the subcellular localization pattern and molecular determinants for the nuclear import of EP0 were investigated. EP0 was demonstrated to predominantly target the nucleus in both PRV infected- and plasmid-transfected cells. Furthermore, the nuclear import of EP0 was shown to be dependent on the Ran-, importin α1-, α3-, α7-, ß1- and transportin-1-mediated multiple pathways. Taken together, these data will open up new horizons for portraying the biological roles of EP0 in the course of PRV lytic cycle.
Subject(s)
Active Transport, Cell Nucleus , Herpesvirus 1, Suid/metabolism , Viral Proteins/metabolism , Animals , Cell Line , Karyopherins/metabolism , Protein BindingABSTRACT
BACKGROUND/AIMS: Epstein-Barr virus (EBV) BFLF2, the homologue of herpes simplex virus 1 (HSV-1) UL31, is crucial for the efficient viral DNA packaging and primary egress across the nuclear membrane. However, we still do not know its subcellular transport mechanisms. METHODS: Interspecies heterokaryon assays were utilized to detect the nucleocytoplasmic shuttling of BFLF2, and mutation analysis, plasmid transfection and fluorescence microscopy assays were performed to identify the functional nuclear localization sequence (NLS) and nuclear export sequence (NES) of BFLF2 in live cells. Furthermore, the nuclear import and export of BFLF2 were assessed by confocal microscopy, co-immunoprecipitation and immunoblot assays. RESULTS: BFLF2 was confirmed to shuttle between the nucleus and cytoplasm. Two predicted NESs were shown to be nonfunctional, yet we proved that the nuclear export of BFLF2 was mediated through transporter associated with antigen processing (TAP), but not chromosomal region maintenance 1 (CRM1) dependent pathway. Furthermore, one functional NLS, 22RRLMHPHHRNYTASKASAH40, was identified, and the aa22-23, aa22-25, aa28-30 and aa37-40 had an important role in the nuclear localization of BFLF2. Besides, the nuclear import of BFLF2 was demonstrated through Ran-, importin α7-, importin ß1- and transportin-1-dependent mechanism that does not require importin α1, α3 and α5. CONCLUSION: These works are of significance for the further study of the functions of BFLF2 during EBV infection, as well as for further insights into the design of new antiviral drug target and vaccine development against EBV.
Subject(s)
Active Transport, Cell Nucleus , Cell Nucleus/metabolism , Epstein-Barr Virus Infections/metabolism , Herpesvirus 4, Human/physiology , Viral Proteins/metabolism , Amino Acid Sequence , Animals , COS Cells , Cell Nucleus/virology , Chlorocebus aethiops , Cytoplasm/metabolism , Cytoplasm/virology , Epstein-Barr Virus Infections/virology , HEK293 Cells , Humans , Mice , NIH 3T3 Cells , Nuclear Export Signals , Nuclear Localization SignalsABSTRACT
As a crucial protein, the herpes simplex virus 1 (HSV-1) UL2 protein has been shown to take part in various stages of viral infection, nonetheless, its exact subcellular localization and transport molecular determinants are not well known thus far. In the present study, by using live cells fluorescent microscopy assay, UL2 tagged with enhanced yellow fluorescent protein was transiently expressed in live cells and showed a completely nuclear accumulation without the presence of other HSV-1 proteins. Moreover, the nuclear transport of UL2 was characterized to be assisted by multiple transport pathways through Ran-, importin α1-, α5-, α7-, ß1- and transportin-1 cellular transport receptors. Consequently, these results will improve understanding of UL2-mediated biological functions in HSV-1 infection cycles.
Subject(s)
Herpes Simplex/physiopathology , Herpes Simplex/virology , Herpesvirus 1, Human/physiology , Uracil-DNA Glycosidase/metabolism , Viral Proteins/metabolism , Active Transport, Cell Nucleus , Animals , COS Cells , Cell Nucleus/metabolism , Chlorocebus aethiops , HEK293 Cells , Humans , Subcellular Fractions , Tissue Distribution , Uracil-DNA Glycosidase/genetics , Viral Proteins/genetics , alpha Karyopherins/metabolism , beta Karyopherins/metabolismABSTRACT
This study investigated the pro-proliferative effect of hyaluronic acid (HA) on human amniotic mesenchymal stem cells (hAMSCs) and the underlying mechanisms. Treatment with HA increased cell population growth in a dose- and time-dependent manner. Analyses by flow cytometry and immunocytochemistry revealed that HA did not change the cytophenotypes of hAMSCs. Additionally, the osteogenic, chondrogenic, and adipogenic differentiation capabilities of these hAMSCs were retained after HA treatment. Moreover, HA increased the mRNA expressions of wnt1, wnt3a, wnt8a, cyclin D1, Ki-67, and ß-catenin as well as the protein level of ß-catenin and cyclin D1 in hAMSCs; and the nuclear localization of ß-catenin was also enhanced. Furthermore, the pro-proliferative effect of HA and up-regulated expression of Wnt/ß-catenin pathway-associated proteins - wnt3a, ß-catenin and cyclin D1 in hAMSCs were significantly inhibited upon pre-treatment with Wnt-C59, an inhibitor of the Wnt/ß-catenin pathway. These results suggest that HA may positively regulate hAMSCs proliferation through regulation of the Wnt/ß-catenin signaling pathway.
Subject(s)
Amnion/cytology , Hyaluronic Acid/pharmacology , Mesenchymal Stem Cells/cytology , Mesenchymal Stem Cells/metabolism , Wnt Signaling Pathway/drug effects , Benzeneacetamides/pharmacology , Cell Differentiation/drug effects , Cell Lineage/drug effects , Cell Proliferation/drug effects , Cell Shape/drug effects , Cyclin D1/metabolism , Female , Fluorescent Antibody Technique , Gene Expression Regulation/drug effects , Humans , Mesenchymal Stem Cells/drug effects , Osteogenesis/drug effects , Phenotype , Pregnancy , Proto-Oncogene Proteins c-myc/metabolism , Pyridines/pharmacology , Wnt Signaling Pathway/genetics , beta Catenin/metabolismABSTRACT
Natural killer cells (NK cells) and natural killer T cells (NKT cells) play a role in anti-infection, anti-tumor, transplantation immunity, and autoimmune regulation. However, the role of NK and NKT cells during Schistosoma japonicum (S. japonicum) infection has not been widely reported, especially regarding lung infections. The aim of this study was to research the NK and NKT cell response to S. japonicum infection in the lungs of mice. Using immunofluorescent histological analysis, NK and NKT cells were found near pulmonary granulomas. Moreover, flow cytometry revealed that the percentage and number of pulmonic NK cells in S. japonicum-infected mice were significantly increased (P < 0.05). However, the percentage and cell number of NKT cells were decreased compared to those of normal mice (P < 0.05). The expression of CD69 on pulmonic NK and NKT cells was increased after infection (P < 0.05), and CD25 expression increased only on NKT cells (P < 0.05). Intracellular cytokine staining showed a higher percentage of IFN-γ+ and lower percentage of IL-5+ pulmonic NK cells (P < 0.05) compared to controls. However, the percentage of IL-17+, IL-10+, and IL-5+ pulmonic NKT cells significantly increased (P < 0.05). Additionally, there was a significant decrease in NKG2A/C/E (CD94) expression and an increase of NKG2D (CD314) expression on pulmonic NKT cells (P < 0.05), which might serve as a mechanism for NKT cell activation during S. japonicum infection.
Subject(s)
Killer Cells, Natural/immunology , Natural Killer T-Cells/immunology , Schistosoma japonicum/physiology , Schistosomiasis japonica/immunology , Animals , Female , Humans , Interferon-gamma/genetics , Interleukin-10/genetics , Interleukin-10/immunology , Interleukin-17/genetics , Interleukin-17/immunology , Interleukin-5/genetics , Interleukin-5/immunology , Lung/immunology , Lymphocyte Activation/immunology , Mice , Mice, Inbred C57BL , Schistosoma japonicum/immunology , Schistosomiasis japonica/genetics , Schistosomiasis japonica/parasitologyABSTRACT
The herpes simplex virus 1 (HSV-1) UL31 protein is a multifunctional nucleoprotein that is important for viral infection; however, little is known concerning its subcellular localization signal. Here, by transfection with a series of HSV-1 UL31 deletion mutants fused to enhanced yellow fluorescent protein (EYFP), a bipartite nuclear localization signal (NLS) was identified and mapped to amino acids (aa) 1 to 27 (MYDTDPHRRGSRPGPYHGKERRRSRSS). Additionally, fluorescence results showed that the predicted nuclear export signal (NES) might be nonfunctional, and the functional NES of UL31 might require a specific conformation. Taken together, these results would provide significant information for the study of the biological function of UL31 during HSV-1 infection.
Subject(s)
Active Transport, Cell Nucleus/physiology , Herpesvirus 1, Human/metabolism , Nuclear Localization Signals/metabolism , Nuclear Proteins/metabolism , Viral Proteins/metabolism , Amino Acid Sequence , Animals , Bacterial Proteins , COS Cells , Chlorocebus aethiops , Cloning, Molecular , Gene Expression Regulation, Viral , Herpesvirus 1, Human/genetics , Luminescent Proteins , Mutation , Nuclear Localization Signals/genetics , Nuclear Proteins/genetics , Protein Transport , Viral Proteins/geneticsABSTRACT
Herpes simplex virus 1 (HSV-1) UL31 is a multifunctional protein and important for HSV-1 infection. Pseudorabies virus (PRV) UL31 is a late protein homologous to HSV-1 UL31. Previous studies showed that PRV UL31 is predominantly localized to nucleus, however, the molecular determinants for its nuclear import were unclear to date. Here, by utilizing live cells fluorescent microscopy, UL31 fused with enhanced yellow fluorescent protein was transiently expressed in live cells and confirmed to exclusively target to the nucleus in the absence of other viral proteins. Furthermore, the nuclear import of UL31 was found to be dependent on the Ran-, importin α1-, α3-, α5-, α7-, ß1-and transportin-1-mediated pathway. Therefore, these results would open up new avenues for depicting the biological functions of UL31 during PRV infection.
Subject(s)
Cell Nucleus/virology , Herpesvirus 1, Suid/physiology , Pseudorabies/metabolism , Pseudorabies/virology , Viral Proteins/metabolism , Active Transport, Cell Nucleus , Animals , COS Cells , Cell Nucleus/metabolism , Chlorocebus aethiops , HEK293 Cells , Humans , Karyopherins/metabolism , Signal TransductionABSTRACT
The Mongolian gerbil (Meriones unguiculatus) has been indicated to be a useful experimental model host for studying nematode. To understand the possibility of the Mongolian gerbil as an animal model of Angiostrongylus cantonensis infection, we investigated the development, migration, and tissue distribution of A. cantonensis and pathological changes in the brain and lungs of the infected Mongolian gerbils. The first stage larvae of A. cantonensis in the stool of the infected gerbils were examined by direct smear method at 45th day postinfection (PI). In addition, a group of the infected gerbils were orally fed with albendazole (100 mg/kg/day/gerbil) at the 8th day PI and continued for 3 consecutive days. The results showed that mortality rate of Mongolian gerbils infected with 10 third stage larvae of A. cantonensis was about 62% at the 30th day PI; the peak period of death was from the 23rd to 30th day PI. About 93% (27/29) of the worms in survivors of infected gerbils could develop to complete sexual maturity at the 46th day PI, and the examinations of 12 gerbils in G3 group revealed that first stage larvae of A. cantonensis could be found in the feces of 4 gerbils at the 45th day PI. About 80% of the worms were in the brain of infected gerbils and 20% in the lungs from the 23rd to 25th day PI; during migration of the worms from the brain to lungs, more than 90% of the worms arrived to the lungs and less than 10% of them still stayed in the brain during from the 45th to 46th day PI. Pathological examination revealed that injuries induced by A. cantonensis in infected gerbils were characterized by eosinophilic meningitis and granulomatous pneumonia. Otherwise, albendazole exhibited a good larvicidal activity in the infected Mongolian gerbils. In contrast with infected control group, no gerbils died in administering albendazole, no worms were recovered, and no nervous system symptoms caused by the infection occurred at the 26th day PI. These findings clearly indicated that Mongolian gerbils should be a potential incomplete permissive host for A. cantonensis and are very susceptive to A. cantonensis infection. Moreover, it has been certified that gerbils as an experimental animal can be used in screening of drug against A. cantonensis. The study provides us a new, selectable experimental animal model for research of A. cantonensis.
Subject(s)
Angiostrongylus cantonensis , Disease Models, Animal , Strongylida Infections/pathology , Albendazole/therapeutic use , Animals , Anthelmintics/therapeutic use , Brain/parasitology , Brain/pathology , Female , Gerbillinae , Larva , Lung/parasitology , Lung/pathology , Male , Strongylida Infections/drug therapyABSTRACT
Carboxylatopillar[5]arene (CP[5]A), a new water-soluble macrocyclic synthetic receptor, has been employed as a stabilizing ligand for in situ preparation of gold nanoparticles (AuNPs) to gain new insights into supramolecular host-AuNP interactions. CP[5]A-modified AuNPs with good dispersion and narrow size distributions (3.1 ± 0.5 nm) were successfully produced in aqueous solution, suggesting a green synthetic pathway for the application of AuNPs in biological systems. Supramolecular self-assembly of CP[5]A-modified AuNPs mediated by suitable guest molecules was also investigated, indicating that the new hybrid material is useful for sensing and detection of the herbicide paraquat.
Subject(s)
Gold/chemistry , Metal Nanoparticles/chemistry , Quaternary Ammonium Compounds/chemistry , Viologens/chemistry , Models, Molecular , Molecular Structure , Particle Size , Surface PropertiesABSTRACT
Mechanized silica nanoparticles, equipped with pillar[5]arene-[2]pseudorotaxane nanovalves, operate in biological media to trap cargos within their nanopores, but release them when the pH is lowered or a competitive binding agent is added. Although cargo size plays an important role in cargo loading, cargo charge-type does not appear to have any significant influence on the amount of cargo loading or its release. These findings open up the possibility of using pillar[n]arene and its derivatives for the formation of robust and dynamic nanosystems that are capable of performing useful functions.
ABSTRACT
The immune responses of Angiostrongylus cantonensis infection are closely relevant to the host's self-protection and the nematode's pathogenesis. In the present study, BALB/c mice were randomly divided into uninfected control group, infection group 1, and infection group 2. The infection group 1 and infection group 2 were infected with 20 and 40 third-stage larvae of A. cantonensis per mouse, respectively. The splenocytes from the mice were collected and cultured on the 19th and 25th days post-infection; the subtypes of T cells in splenocytes were detected by flow cytometry with fluorescence staining method, and the cytokines in cultured supernatants of splenocytes were assayed by the method of ELISA. The specific IgG and IgE antibodies in sera of the mice were periodically detected by ELISA. The results showed that the percentages of CD4(+) and CD4(+) IL-4(+) T cells in splenocytes of infected mice were much higher (P < 0.05) than those in control mice; however, the percentages of CD4(+) IL-17(+) and CD4(+) IFN-γ(+) T cell were much lower(P < 0.01) after the infection. The levels of CD8(+) T cells in infected mice also rose, but differences between control mice and infected mice were not significant. In comparison with control mice, the concentration of IL-4 in the cultured supernatants of splenocytes in infected mice increased significantly (P < 0.05), but that of IL-17 decreased significantly (P < 0.01). In addition, the number of larvae infected and days after infection may influence levels of the T cell subtypes and the cytokines in spleen, too (P > 0.05). On humoral immunity, the levels of specific IgG antibodies in sera rose a bit at the fifth day post-infection, and reached a peak at the 20th day post-infection; the specific IgE antibodies gradually heightened during first 10 days post-infection; then, it showed a downward trend during the 15th to 25th days post-infection. It is evident that the percentages of CD4(+) T lymphocytes of spleen in the mice infected with A. cantonensis markedly increase and polarize to Th2 phenotypes, and the function of Th17 cells is inhibited. In addition, the elevation of specific IgG antibodies in sera of the infected mice is more significant than that of specific IgE antibodies.
Subject(s)
Angiostrongylus cantonensis/immunology , Antibodies, Helminth/blood , Spleen/immunology , Strongylida Infections/immunology , T-Lymphocytes/immunology , Animals , Cytokines/metabolism , Disease Models, Animal , Enzyme-Linked Immunosorbent Assay , Female , Flow Cytometry , Immunoglobulin E/blood , Immunoglobulin G/blood , Mice , Mice, Inbred BALB C , T-Lymphocyte Subsets/immunologyABSTRACT
This experimental research was aimed to establish an optimum system of enucleation, purification and identification for preparing the cytoplasts of suspension culture cells in order to undertake cell recombination. Human leukemia HL-60 cells in suspension culture were purified by 42% Percoll density gradient centrifugation and low-speed centrifugation at 1 500r/min, respectively. The purified HL-60 cells were treated with cytochalasin B (CB) alone or combined with colcchicine and enucleated by isopycnic gradient centrifugation on 50% Percoll at 25 degrees C and 34 degrees C, respectively. Cytoplasts made from HL-60 cells were purified through gradient centrifugation by 37%, 38% and 40% Percoll, respectively. The final cytoplasts were identified by Wright-Giemsa staining and 4,6-diamidino-2-phenylidole dihydrochloride (DAPI)/5, 6-carboxyflu-orescein diacetate succinimidyl ester (CFSE) double-staining. The phenotype and mitochondrial membrane potential of HL-60 cytoplasts were analyzed by flow cytometry. The results indicated that the enucleation ratio of HL-60 cells induced by CB combined with colcchicine was up to 91. 98% +/-4. 29%, which was significantly higher than that in CB alone group (74. 95% +/- 3. 02%)(P<0. 01). The rates of enucleation and cytoplast with diameter over 5min in 34 degrees C group were higher than those in 25 degrees C group (all P<0. 01). The cytoplast purities were (95.43 +/- 0. 59)% in 38% Percoll groups,which were higher than those of 40% Percoll (P<0. 05). Nucleus and caryoplasm could be clearly distinguished by DAPI and CFSE double labeling. The results further showed that the phenotype of HL-60 cytoplasts had no significant change, and the activity of the cytoplasts was above 80% within 12h. It is concluded that enucleation throuth density gradient centrifugation on 50% Percoll mediated by CB combined with colcchicine, 38%Percoll of purification followed by DAPI/CFSE double labeling and MMP detection is an optimum scheme for preparation and identification of cytoplast from suspension culture cells.
Subject(s)
Cell Compartmentation , Cell Nucleus , Cytochalasin B/pharmacology , Cytoplasm , Cell Separation , Centrifugation, Density Gradient , Colchicine/analogs & derivatives , Colchicine/pharmacology , HL-60 Cells , HumansABSTRACT
A practical and effective trifluoromethanesulfonic acid (TfOH)-catalyzed cyclooligomerization strategy was developed for the synthesis of functionalized pillar[n]arenes and copillar[5]arenes from 1,4-dialkoxybenzenes with paraformaldehyde under mild reaction conditions, and the reaction mechanism of solution-phase catalytic synthesis of pillararenes was investigated by room-temperature X-band ESR spectroscopy, mass spectroscopy, NMR and control experiments, suggesting a free radical process initially and a Friedel-Crafts alkylation process during the consequent coupling and ring-closure stage.
ABSTRACT
Cordyceps taii, an edible medicinal mushroom native to south China, is recognized as an unparalleled resource of healthy foods and drug discovery. In the present study, the antioxidant pharmacological properties of C. taii were systematically investigated. In vitro assays revealed the scavenging activities of the aqueous extract and polysaccharides of C. taii against various free radicals, that is, 1,1-diphenyl-2-picrylhydrazyl radical, hydroxyl radical, and superoxide anion radical. The EC(50) values for superoxide anion-free radical ranged from 2.04 mg/mL to 2.49 mg/mL, which was at least 2.6-fold stronger than that of antioxidant thiourea. The polysaccharides also significantly enhanced the antioxidant enzyme activities (superoxide dismutase, catalase, and glutathione peroxidase) and markedly decreased the malondialdehyde production of lipid peroxidation in a D-galactose-induced aging mouse model. Interestingly, the immune function of the administration group was significantly boosted compared with the D-galactose-induced aging model group. Therefore, the C. taii polysaccharides possessed potent antioxidant activity closely associated with immune function enhancement and free radical scavenging. These findings suggest that the polysaccharides are a promising source of natural antioxidants and antiaging drugs. Consequently, a preliminary chemical investigation was performed using gas chromatography-mass spectroscopy and revealed that the polysaccharides studied were mainly composed of glucose, mannose, and galactose. Fourier-transform infrared spectra also showed characteristic polysaccharide absorption bands.