In vitro rapid evolution of fungal immunomodulatory proteins by DNA family shuffling

Fungal immunomodulatory proteins (FIPs) found in a wide variety of mushrooms hold significant therapeutic potential. Despite much research, the structural determinants for their immunomodulatory functions remain unknown. In this study, a DNA shuffling technique was used to create two shuffled FIP protein libraries: an intrageneric group containing products of shuffling between FIP-glu (FIP gene isolated from Ganoderma lucidum) and FIP-gsi (FIP gene isolated from Ganoderma sinense) genes and an intergeneric group containing the products of shuffling between FIP-glu, FIP-fve (FIP gene isolated from Flammulina velutipes), and FIP-vvo (FIP gene isolated from Volvariella volvacea) genes. The gene shuffling generated 426 and 412 recombinant clones, respectively. Using colony blot analysis, we selected clones that expressed relatively high levels of shuffled gene products recognized by specific polyclonal antibodies. We analyzed the DNA sequences of the selected shuffled genes, and testing of their protein products revealed that they maintained functional abilities to agglutinate blood cells and induce cytokine production by splenocytes from Kunming mice in vitro. Meanwhile, the relationships between protein structure and the hemagglutination activity and between the changed nucleotide sites and expression levels were explored by bioinformatic analysis. These combined analyses identified the nucleotide changes involved in regulating the expression levels and hemagglutination activities of the FIPs. Therefore, we were able to generate recombinant FIPs with improved biological activities and expression levels by using DNA shuffling, a powerful tool for the generation of novel therapeutic proteins and for their structural and functional studies.     

Expression of a keratinase (kerA) gene from Bacillus licheniformis in Escherichia coli and characterization of the recombinant enzymes

The gene kerA (1,047 bp) encoding the main keratinase from Bacillus licheniformis was cloned into two conventional vectors, pET30α and pET32α, and expressed in Escherichia coli. From SDS-PAGE analysis, the recombinant keratinases were 45 and 55 kDa. They had different optimal pH values (7.5 and 8.5) but the same optimum temperature of 50 °C. The recombinant keratinase produced in E. coli pET30α-kerA was more stable than that produced in E. coli pET32α-kerA, and retained approx. 70 % of its total enzyme activity after 30 min at 70 °C.     

Phorbol 12-myristate 13-acetate induces protein kinase ceta-specific proliferative response in astrocytic tumor cells

Protein kinase C (PKC) activation has been implicated in cellular proliferation in neoplastic astrocytes. The roles for specific PKC isozymes in regulating this glial response, however, are not well understood. The aim of this study was to characterize the expression of PKC isozymes and the role of PKC-eta expression in regulating cellular proliferation in two well characterized astrocytic tumor cell lines (U-1242 MG and U-251 MG) with different properties of growth in cell culture. Both cell lines expressed an array of conventional (alpha, betaI, betaII, and gamma) and novel (theta and epsilon) PKC isozymes that can be activated by phorbol myristate acetate (PMA). Another novel PKC isozyme, PKC-eta, was only expressed by U-251 MG cells. In contrast, PKC-delta was readily detected in U-1242 MG cells but was present only at low levels in U-251 MG cells. PMA (100 nm) treatment for 24 h increased cell proliferation by over 2-fold in the U-251 MG cells, whereas it decreased the mitogenic response in the U-1242 MG cells by over 90%. When PKC-eta was stably transfected into U-1242 MG cells, PMA increased cell proliferation by 2.2-fold, similar to the response of U-251 MG cells. The cell proliferation induced by PMA in both the U-251 MG and U-1242-PKC-eta cells was blocked by the PKC inhibitor bisindolylmaleimide (0.5 micrometer) and the MEK inhibitor, PD 98059 (50 micrometer). Transient transfection of wild type U-251 with PKC-eta antisense oligonucleotide (1 micrometer) also blocked the PMA-induced increase in [(3)H]thymidine incorporation. The data demonstrate that two glioblastoma lines, with functionally distinct proliferative responses to PMA, express different novel PKC isozymes and that the differential expression of PKC-eta plays a determining role in the different proliferative capacity.     

Antioxidant,anticancer, apoptosis properties and chemical composition of black truffle Terfezia claveryi

Desert truffles are seasonal and important edible fungi that grow wild in many countries around the world. Truffles are natural food sources that have significant compositions. In this work, the antioxidant, chemical composition, anticancer, and antiangiogenesis properties of the Terfezia claveryi truffle were investigated. Solvent extractions of the T. claveryi were evaluated for antioxidant activities using (DPPH, FRAP and ABTS methods). The extracts cytotoxicity on the cancer cell lines (HT29, MCF-7, PC3 and U-87 MG) was determined by MTT assay, while the anti-angiogenic efficacy was tested using ex-vivo assay. All extracts showed moderate anticancer activities against all cancer cells (p < 0.05). The hexane extract inhibited the brain cell line (U-87 MG) with an IC₅₀ of 50 μg/ml and significantly promoted cell apoptosis through the mitochondrial pathway and DNA fragmentation p < 0.001. The ethanol extract demonstrated potent antioxidants; DPPH, FRAP, and ABTS with an IC₅₀ value of 52, 48.5 and 64.7 μg/ml, respectively. In addition, the hexane and ethyl acetate extract significantly (p < 0.001) inhibited the sprouting of microvessels by 100% and 81.2%, at 100 μg/ml, respectively. The GC analysis of the most active extract (hexane) showed the presence of several potent phytochemicals such as stigmasterol, beta-Sitosterol, squalene, lupeol, octadecadienoic acid, and oleic acid.     

Structural Characterization and Functional Validation of Aldose Reductase from the Resurrection Plant Xerophyta viscosa

Aldose reductases are key enzymes in the detoxification of reactive aldehyde compounds like methylglyoxal (MG) and malondialdehyde. The present study describes for first time the preliminary biochemical and structural characterization of the aldose reductase (ALDRXV4) enzyme from the resurrection plant Xerophyta viscosa. The ALDRXV4 cDNA was expressed in E. coli using pET28a expression vector, and the protein was purified using affinity chromatography. The recombinant protein showed a molecular mass of ~36 kDa. The K _M (1.2 mM) and k _cat (14.5 s^?1) of the protein determined using MG as substrate was found to be comparable with other reported homologs. Three-dimensional structure prediction based on homology modeling suggested several similarities with the other aldose reductases reported from plants. Circular dichroism spectroscopy results supported the bioinformatic prediction of alpha–beta helix nature of aldose reductase proteins. Subcellular localization studies revealed that the ALDRXV4-GFP fusion protein was localized both in the nucleus and the cytoplasm. The E. coli cells overexpressing ALDRXV4 exhibited improved growth and showed tolerance against diverse abiotic stresses induced by high salt (500 mM NaCl), osmoticum (10 % PEG 6000), heavy metal (20 mM CdCl₂), and MG (5 mM). Based on these results, we propose that ALDRXV4 gene from X. viscosa could be a potential candidate for developing stress-tolerant crop plants.     

A comparative study on phosphotransferase activity of acid phosphatases from Raoultella planticola and Enterobacter aerogenes on nucleosides,sugars, and related compounds

Natural and modified nucleoside-5′-monophosphates and their precursors are valuable compounds widely used in biochemical studies. Bacterial nonspecific acid phosphatases (NSAPs) are a group of enzymes involved in the hydrolysis of phosphoester bonds, and some of them exhibit phosphotransferase activity. NSAP containing Enterobacter aerogenes and Raoultella planticola whole cells were evaluated in the phosphorylation of a wide range of nucleosides and nucleoside precursors using pyrophosphate as phosphate donor. To increase the productivity of the process, we developed two genetically modified strains of Escherichia coli which overexpressed NSAPs of E. aerogenes and R. planticola. These new recombinant microorganisms (E. coli BL21 pET22b-phoEa and E. coli BL21 pET22b-phoRp) showed higher activity than the corresponding wild-type strains. Reductions in the reaction times from 21 h to 60 min, from 4 h to 15 min, and from 24 h to 40 min in cases of dihydroxyacetone, inosine, and fludarabine, respectively, were obtained.     

Molecular cloning and expression of ranalexin, a bioactive antimicrobial peptide from Rana catesbeiana in Escherichia coli and assessments of its biological activities

The coding sequence, which corresponds to the mature antimicrobial peptide ranalexin from the frog Rana catesbeiana, was chemically synthesized with preferred codons for expression in Escherichia coli. It was cloned into the vector pET32c (+) to express a thioredoxin-ranalexin fusion protein which was produced in soluble form in E. coli BL21 (DE3) induced under optimized conditions. After two purification steps through affinity chromatography, about 1 mg of the recombinant ranalexin was obtained from 1 L of culture. Mass spectrometrical analysis of the purified recombinant ranalexin demonstrated its identity with ranalexin. The purified recombinant ranalexin is biologically active. It showed antibacterial activities similar to those of the native peptide against Staphylococcus aureus, Streptococcus pyogenes, E. coli, and multidrug-resistant strains of S. aureus with minimum inhibitory concentration values between 8 and 128 μg/ml. The recombinant ranalexin is also cytotoxic in HeLa and COS7 human cancer cells (IC₅₀?=?13–15 μg/ml).     

Intracellular production of IFN-alpha 2b in Lactococcus lactis

Human interferon alpha (IFN-α) was expressed in two strains of Lactococcus lactis by aid of two promoters (P32 and Pnis) giving rise to two recombinant strains: MG:IFN and NZ:IFN, respectively. The expression of IFN was confirmed by ELISA and western blotting. Highest production was achieved using glucose for growth of both recombinant strains with nisin, used for induction of the recombinant strain with Pnis promoter, at 30 ng/ml. The optimum time for MG:IFN was 9 h and for NZ:IFN was 4.5 h. The highest productions by MG:IFN and NZ:IFN were 1.9 and 2.4 μg IFN/l, respectively. Both of the expressed IFNs showed bioactivities of 1.9 × 10⁶ IU/mg that were acceptable for further clinical studies.     

Purification and characterization of a laccase from Coprinopsis cinerea in Pichia pastoris

A modified laccase gene, CcLCC6, from Coprinopsis cinerea was chemically synthesized according to the yeast codon bias and expressed in Pichia pastoris. The main properties of laccase, effects of ions and inhibitors, and optimal condition for decolouring malachite green (MG) were investigated in this study. The optimal pH level and temperature of laccase are 3.0 and 40 °C, respectively. The metal ions Mn²⁺, Zn²⁺, Fe³⁺ and Al³⁺ could inhibit laccase activity, as well as 1 mM of sodium dodecyl sulphate and sodium thiosulphate. 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), as a mediator, was necessary in decolorizing MG. The optimal pH and temperature for MG decolorization were 3.0 and 50 °C, respectively. Approximately 0.02 μM recombinant laccase could effectively decolour 0.05 mM of MG in 1 h. CcLCC6I could inhibit the toxicity of MG to P. pastoris. This is the first report on the successful expression in P. pastoris of CcLCC6I and its enzymatic property. Laccase can also be considered as a candidate for treating industrial effluent containing MG.     

siRNA-mediated knockdown of SMC1A expression suppresses the proliferation of glioblastoma cells

SMC1A is a member of cohesin complex which has essential functions in cell cycle progression and DNA repair. Therefore, we choose SMC1A as a target gene therapy of glioblastoma. It is well known that glioblastoma has very low survival rate because of ineffectiveness of conventional treatments. This study was designed to explore the possibilities of small interfering RNA (siRNA)-mediated SMC1A silencing as alternative method of treatment. We found that the lentivirus-mediated RNAi system efficiently decreased the expression level of SMC1A. Inhibiting SMC1A expression efficiently (P < 0.001) resulted in inhibiting the proliferation and colony formation of U251 and U87MG cells. Moreover, we found that SMC1A silencing led to S cell-cycle arresting. Collectively, these results demonstrated the possibility of siRNA-mediated silencing of SMC1A as a therapeutic tool for the treatment of glioblastoma.     

The plant Selaginella moellendorffii possesses enzymes for synthesis and hydrolysis of the compatible solutes mannosylglycerate and glucosylglycerate

A mannosylglycerate synthase (MgS) gene detected in the genome of Selaginella moellendorffii was expressed in E. coli and the recombinant enzyme was purified and characterized. A remarkable and unprecedented feature of this enzyme was the ability to efficiently synthesize mannosylglycerate (MG) and glucosylglycerate (GG) alike, with maximal activity at 50 °C, pH 8.0 and with Mg²⁺ as reaction enhancer. We have also identified a novel glycoside hydrolase gene in this plant’s genome, which was functionally confirmed to be highly specific for the hydrolysis of MG and GG and named MG hydrolase (MgH), due to its homology with bacterial MgHs. The recombinant enzyme was maximally active at 40 °C and at pH 6.0–6.5. The activity was independent of cations, but Mn²⁺ was a strong stimulator. Regardless of these efficient enzymatic resources we could not detect MG or GG in S. moellendorffii or in the extracts of five additional Selaginella species. Herein, we describe the properties of the first eukaryotic enzymes for the synthesis and hydrolysis of the compatible solutes, MG and GG.     

Oxidative decarboxylation of mandelic acid derivative by recombinant Escherichia coli: a novel method of ethyl vanillin synthesis

The benzoylformate decarboxylase gene (mdlC) from Pseudomonas putida was expressed in Escherichia coli BL21(DE3). The recombinant strain together with E. coli/pET30a-mdlB converted (S)-3-ethoxy-4-hydroxymandelic acid (S-EMA) into ethyl vanillin without ethyl vanillin degradation. 4 g ethyl vanillin/l was obtained from 10 g EMA/l within 12 h at 30 °C. This is the first report on the biotransformation of (S)-EMA to ethyl vanillin.     

Downregulation of Oxytocin Receptor Decreases the Length of Projections Stimulated by Retinoic Acid in the U-87MG Cells

Oxytocin is a neuropeptide widely expressed in the brain. Oxytocin plays a role in both proliferation and differentiation of various cells. Previous studies have suggested that oxytocin could affect the morphology of neuronal cells, therefore the objective of the present study was to test whether (1) oxytocin receptor stimulation/inhibition by specific ligands may change cell morphology and gene expression of selected cytoskeletal proteins (2) oxytocin receptor silencing/knockdown may decrease the length of cell projections (3) oxytocin receptor knockdown may affect human glioblastoma U-87MG cell survival. We confirmed the stimulatory effect of retinoic acid (10 µM) and oxytocin (1 µM) on projection growth. The combination of retinoic acid (10 µM) and oxytocin receptor antagonist (L-371,257, 1 µM) decreased projections length. Contrary to our assumptions, oxytocin receptor silencing did not prevent stimulation of length of projection by retinoic acid. Retinoic acid’s and oxytocin’s stimulation of projections length was significantly blunted in U-87MG cells with oxytocin receptor knockdown. Cell viability was significantly decreased in U-87MG cells with oxytocin receptor knockdown. Significantly higher levels of mRNA for cytoskeletal proteins drebrin and vimentin were observed in response to oxytocin incubation for 48 h. The data obtained in the present study clearly show that oxytocin induces formation and elongation of cell projections in astrocyte-like U-87MG cells. The effect is mediated by oxytocin receptors and it is accompanied by an increase in gene expression of drebrin and vimentin. Thus, oxytocin receptor signaling, particularly in the glial cells, may play an important role in native cell life, differentiation processes, and tumor progression, as well.     

Effect of combined treatment with recombinant interleukin-2 and allicin on pancreatic cancer

This study aimed to evaluate the efficacy of combined treatment with recombinant interleukin-2 (rIL-2) and allicin on pancreatic cancer and explore the potential immunological mechanism. A total of 60 C57/BL6 nude mice pancreatic cancer xenograft models were randomized into four groups of 15 mice per group: control group, allicin treatment group, rIL-2 treatment group, combined treatment with allicin and rIL-2 group. Mice in each group were treated with saline, rIL-2, allicin, or combination of rIL-2 and allicin by weekly i.v injection for four weeks. After four weeks of treatment, eyeballs of the mice were extracted and blood was drawn, percentages of CD4+T, CD8+T and NK cell were analyzed by FACS, IFN-γ level was detected by ELISA. One mouse in each group was sacrificed to measure the weight and volume of the tumor and prepared to the paraffin section of tumor tissue. Apoptosis of the tumor cells was analyzed by TUNEL and FACS. Other mice continued to receive treatment, survival period were compared between each group. We observed a significant suppression of xenograft growth and a significant prolonged survival time in the combined treatment with allicin and rIL-2 group (P < 0.05). The most amount of apoptotic cells were observed in the combined therapy group (P < 0.05). The percentages of CD4+T, CD8+T and NK cell and serum IFN-γ level increased significantly in the combined treatment group compared with other groups (P < 0.05). Combined treatment with allicin and rIL-2 resulted in suppression of tumor growth and prolonged survival time possibly through activation of CD4+T, CD8+T and NK cell.     

Biochemical and Biophysical Response to Calcium Chloride Stress in Aspergillus niger and its Role in Malachite Green Degradation

Filamentous fungi show great promise in remediation of environmental contaminants such as industrial dyes. In the current study, Aspergillus niger (Genbank ID: JF437542) decolorized 82 % of the test dye malachite green (MG; 50 mg/l) during cultivation for 24 h. The organism decolorized only 6 % of the MG at higher concentration (250 mg MG/l) during the same time period and growth was inhibited at this higher MG concentration. Exposing A. niger to different types of stress resulted in variable impacts on ability to decolorize MG. CaCl₂ had the largest positive impact on decolorization. A. niger cultures treated with CaCl₂ (1 M) decolorized 46 % of the MG (250 mg/l) in 1 h compared to 6 % in untreated control cultures. CaCl₂ also increased catalase production in A. niger which strongly supported a direct relationship between stress response and decolorizing ability. Spectrophotometric measurement confirmed MG decolorization while Fourier transform infrared spectroscopy suggested that biodegradation of MG occurred. Cultures treated with CaCl₂ accumulated fewer toxic MG by-products than untreated cultures. CaCl₂-induced stress increased the permeability and conductivity of the fungal cell membrane. An observed increase in medium [H⁺] also suggested a change in Ca²⁺/H⁺ exchange capacity in the fungal cell. Calcium ions had a pronounced effect on membrane properties and this may have had an important impact on signal transduction. We conclude that A. niger decolorizes MG and that CaCl₂ enhances this process; the CaCl₂ effect appears to be associated with stress response.     

基于网络药理学分析瑞香素抗多种肿瘤的作用机制及体外实验验证

基于网络药理学预测瑞香素抗恶性胶质瘤、肝癌和三阴性乳腺癌的共同靶点及可能机制,并对其进行体外实验验证。利用Swiss Target Prediction和GeneCards等数据库检索瑞香素与恶性胶质瘤、肝癌和三阴性乳腺癌的共同靶点。使用Cytoscape构建瑞香素-三种肿瘤蛋白质相互作用网络图(PPI)并筛选出核心靶点,并对核心靶点进行GO及KEGG富集分析;通过AutoDock Tools对瑞香素与核心靶点进行分子对接。体外实验验证:采用CCK-8和Western blot法行体外实验验证不同浓度瑞香素对U-251 MG、HepG-2和MDA-MB231细胞系细胞抑制率和P53、RRM2蛋白的表达水平的影响。共筛选出瑞香素抗三种肿瘤核心靶点56个,富集分析显示靶点富集在P53通路和癌症通路,参与细胞周期调节、细胞凋亡、DNA生物合成和修复等生物过程;分子对接结果显示瑞香素与P53、RRM2有较好的结合作用。体外验证实验显示,与对照组比较,瑞香素能显著抑制U-251 MG、HepG-2、MDA-MB231的增殖(P<0.01),并显著上调其P53蛋白及下调RRM2蛋白的表达,且...     

Cloning, Expression, and Characterization of Iron Superoxide Dismutase in Sonneratia alba, a Highly Salt Tolerant Mangrove Tree

In this study, a novel iron superoxide dismutase (FeSOD) gene from Sonneratia alba was cloned and then expressed in Escherichia coli Rosetta-gami, designated as SaFeSOD. The DNA sequence of SaFeSOD contained a 786-bp open reading frame which encodes a 261 amino-acid protein of 30.0 kDa. The 651-bp fragment coding for putative mature SaFeSOD was amplified and inserted into pET15b for expression. This recombinant SaFeSOD was subsequently isolated by Ni-trap column protein purification system. The apparent molecular mass of the purified enzyme was 25 kDa on SDS-PAGE. In comparison with FeSODs from other plant species, all iron-binding sites (His 27, His 80, Asp 164 and His 168) of SaFeSOD were conserved. SaFeSOD was found to have good pH stability in the pH range of 3.5–9.5 at 25 °C after 1 h incubation and was relatively stable and showed 78 % activity when incubated in 50 °C for 1 h. Quantitative real-time PCR experiments demonstrated that SaFeSOD was expressed in leaf, stem, flower, fruit and root tissues with the highest expression in leaf tissues.