Displaying publications 41 - 60 of 382 in total

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  1. Selective isolation and characterisation of novel members of the family Nocardiopsaceae and other actinobacteria from a marine sediment of Tioman Island
    Ng ZY, Tan GYA
    Antonie Van Leeuwenhoek, 2018 May;111(5):727-742.
    PMID: 29511956 DOI: 10.1007/s10482-018-1042-8
    Tioman Island is one of many sources for underexplored actinobacterial diversity in Malaysia. Selective isolation, molecular profiling, 16S rRNA gene sequencing and phylogenetic analyses were carried out to highlight the diversity of the marine actinobacterial community in a sediment collected off Tioman Island. A high number of diverse actinobacteria were recovered using skim milk/HEPES pre-treatment on a mannitol-based medium. A total of 123 actinobacterial strains were isolated, including thirty obligate marine actinobacteria putatively identified as Salinispora spp. Molecular fingerprinting profiles obtained with a double digestion approach grouped the remaining non-Salinispora-like strains into 24 different clusters, with Streptomyces and Blastococcus as the major clusters. A total of 17 strains were identified as novel actinobacterial species within the genera Streptomyces (n = 6), Blastococcus (n = 5), Marinactinospora (n = 3), Nocardiopsis (n = 1), Agromyces (n = 1) and Nonomuraea (n = 1) based on 16S rRNA gene sequence analyses. Polyphasic data from three putative Marinactinospora spp. showed that the strains represent a new genus in the Nocardiopsaceae family. Crude extracts from the strains were also found to inhibit the growth of Gram-positive (Staphylococcus aureus, Bacillus subtilis) and Gram-negative (Providencia alcalifaciens) pathogens. Hierarchical clustering of the bioactivities of an active fraction revealed a unique profile, which is closely related that of fosfomycin.
    Matched MeSH terms: Culture Media
  2. Fulltext Basic fibroblast growth factor with human serum supplementation: enhancement of human chondrocyte proliferation and promotion of cartilage regeneration
    Chua KH, Aminuddin BS, Fuzina NH, Ruszymah BH
    Singapore Med J, 2007 Apr;48(4):324-32.
    PMID: 17384880
    The objectives of this study were to determine the optimum concentration of basic fibroblast growth factor (bFGF) in foetal bovine serum (FBS) or human serum (HS) supplemented medium for adult human nasal septum chondrocyte culture and to evaluate the potential of cartilage regeneration.
    Matched MeSH terms: Culture Media
  3. Fulltext RACK-1 overexpression protects against goniothalamin-induced cell death
    Inayat-Hussain SH, Wong LT, Chan KM, Rajab NF, Din LB, Harun R, et al.
    Toxicol Lett, 2009 Dec 15;191(2-3):118-22.
    PMID: 19698770 DOI: 10.1016/j.toxlet.2009.08.012
    Goniothalamin, a styryllactone, has been shown to induce cytotoxicity via apoptosis in several tumor cell lines. In this study, we have examined the potential role of several genes, which were stably transfected into T-cell lines and which regulate apoptosis in different ways, on goniothalamin-induced cell death. Overexpression of full-length receptor for activated protein C-kinase 1 (RACK-1) and pc3n3, which up-regulates endogenous RACK-1, in both Jurkat and W7.2 T cells resulted in inhibition of goniothalamin-induced cell death as assessed by MTT and clonogenic assays. However, overexpression of rFau (antisense sequence to Finkel-Biskis-Reilly murine sarcoma virus-associated ubiquitously expressed gene) in W7.2 cells did not confer resistance to goniothalamin-induced cell death. Etoposide, a clinically used cytotoxic agent, was equipotent in causing cytotoxicity in all the stable transfectants. Assessment of DNA damage by Comet assay revealed goniothalamin-induced DNA strand breaks as early as 1 h in vector control but this effect was inhibited in RACK-1 and pc3n3 stably transfected W7.2 cells. This data demonstrate that RACK-1 plays a crucial role in regulating cell death signalling pathways induced by goniothalamin.
    Matched MeSH terms: Culture Media
  4. Plant regeneration and floral bud formation from intact floral parts of African violet (Saintpaulia ionantha H. Wendl.) cultured in vitro
    Daud N, Taha RM
    Pak J Biol Sci, 2008 Apr 01;11(7):1055-8.
    PMID: 18810979
    Intact immature flower buds of African violet (Saintpaulia ionantha H. Wendl.) were used as explant sources for in vitro studies. The effect of exogenous hormones, NAA and BAP on the indirect organogenesis of this species was observed. Callus was formed on the cut end (base) of pedicels of floral buds where they were in contact with the medium. When maintained on the same medium, callus was differentiated into adventitious shoots after 10 weeks in culture. MS media supplemented with 2.0 mg L(-1) NAA and 1.0 mg L(-1) BAP gave the highest number of sterile or vegetative floral buds from the surface of callus of the explants, but these buds failed to develop further. The floral buds were expanded as abnormal flowers. The floral structures were smaller in size compared to intact flowers. Petals (corolla) were white to purple in colour but did not form any reproductive organs, i.e., stamens or pistils. All sterile or vegetative floral buds and abnormal flowers survived for 3 months in culture but failed to reach anthesis.
    Matched MeSH terms: Culture Media
  5. Fulltext Soluble factors from stellate cells induce pancreatic cancer cell proliferation via Nrf2-activated metabolic reprogramming and ROS detoxification
    Wu YS, Looi CY, Subramaniam KS, Masamune A, Chung I
    Oncotarget, 2016 Jun 14;7(24):36719-36732.
    PMID: 27167341 DOI: 10.18632/oncotarget.9165
    Pancreatic stellate cells (PSC), a prominent stromal cell, contribute to the progression of pancreatic ductal adenocarcinoma (PDAC). We aim to investigate the mechanisms by which PSC promote cell proliferation in PDAC cell lines, BxPC-3 and AsPC-1. PSC-conditioned media (PSC-CM) induced proliferation of these cells in a dose- and time-dependent manner. Nrf2 protein was upregulated and subsequently, its transcriptional activity was increased with greater DNA binding activity and transcription of target genes. Downregulation of Nrf2 led to suppression of PSC-CM activity in BxPC-3, but not in AsPC-1 cells. However, overexpression of Nrf2 alone resulted in increased cell proliferation in both cell lines, and treatment with PSC-CM further enhanced this effect. Activation of Nrf2 pathway resulted in upregulation of metabolic genes involved in pentose phosphate pathway, glutaminolysis and glutathione biosynthesis. Downregulation and inhibition of glucose-6-phosphate-dehydrogenase with siRNA and chemical approaches reduced PSC-mediated cell proliferation. Among the cytokines present in PSC-CM, stromal-derived factor-1 alpha (SDF-1α) and interleukin-6 (IL-6) activated Nrf2 pathway to induce cell proliferation in both cells, as shown with neutralization antibodies, recombinant proteins and signaling inhibitors. Taken together, SDF-1α and IL-6 secreted from PSC induced PDAC cell proliferation via Nrf2-activated metabolic reprogramming and ROS detoxification.
    Matched MeSH terms: Culture Media, Conditioned/pharmacology
  6. Fulltext The effect of environmental conditions on biofilm formation of Burkholderia pseudomallei clinical isolates
    Ramli NS, Eng Guan C, Nathan S, Vadivelu J
    PLoS One, 2012;7(9):e44104.
    PMID: 22970167 DOI: 10.1371/journal.pone.0044104
    Burkholderia pseudomallei, a Gram-negative saprophytic bacterium, is the causative agent of the potentially fatal melioidosis disease in humans. In this study, environmental parameters including temperature, nutrient content, pH and the presence of glucose were shown to play a role in in vitro biofilm formation by 28 B. pseudomallei clinical isolates, including four isolates with large colony variants (LCVs) and small colony variants (SCVs) morphotypes. Enhanced biofilm formation was observed when the isolates were tested in LB medium, at 30 °C, at pH 7.2, and in the presence of as little as 2 mM glucose respectively. It was also shown that all SVCs displayed significantly greater capacity to form biofilms than the corresponding LCVs when cultured in LB at 37 °C. In addition, octanoyl-homoserine lactone (C(8)-HSL), a quorum sensing molecule, was identified by mass spectrometry analysis in bacterial isolates referred to as LCV CTH, LCV VIT, SCV TOM, SCV CTH, 1 and 3, and the presence of other AHL's with higher masses; decanoyl-homoserine lactone (C(10)-HSL) and dodecanoyl-homoserine lactone (C(12)-HSL) were also found in all tested strain in this study. Last but not least, we had successfully acquired two Bacillus sp. soil isolates, termed KW and SA respectively, which possessed strong AHLs degradation activity. Biofilm formation of B. pseudomallei isolates was significantly decreased after treated with culture supernatants of KW and SA strains, demonstrating that AHLs may play a role in B. pseudomallei biofilm formation.
    Matched MeSH terms: Culture Media/pharmacology
  7. Expansion of human articular chondrocytes and formation of tissue-engineered cartilage: a step towards exploring a potential use of matrix-induced cell therapy
    Munirah S, Samsudin OC, Aminuddin BS, Ruszymah BH
    Tissue Cell, 2010 Oct;42(5):282-92.
    PMID: 20810142 DOI: 10.1016/j.tice.2010.07.002
    Monolayer culture expansion remains as a fundamental step to acquire sufficient number of cells for 3D constructs formation. It has been well-documented that cell expansion is however accompanied by cellular dedifferentiation. In order to promote cell growth and circumvent cellular dedifferentiation, we evaluated the effects of Transforming Growth Factor Beta-2 (TGF-β2), Insulin-like Growth Factor-I (IGF-I) and basic Fibroblast Growth Factor (bFGF) combination on articular chondrocytes culture and 'chondrocytes-fibrin' construct formation. Chondrocytes were serially cultured in: (1) F12:DMEM+10% Foetal Bovine Serum (FBS) with growth factors (FD10GFs), (2) F12:DMEM+2%FBS with the growth factors (FD2GFs) and, (3) F12:DMEM+10%FBS without growth factors (FD) as control. Cultured chondrocytes were evaluated by means of growth kinetics parameters, cell cycle analysis, quantitative phenotypic expression of collagen type II, aggrecan core protein sox-9 and collagen type I and, immunochemistry technique. Harvested chondrocytes were incorporated with plasma-derived fibrin and were polymerized to form the 3D constructs and implanted subcutaneously at the dorsum of athymic nude mice for eight (8) weeks. Resulted constructs were assigned for gross inspections and microscopic evaluation using standard histochemicals staining, immunochemistry technique and, quantitative phenotypic expression of cartilage markers to reassure cartilaginous tissue formation. Growth kinetics performance of chondrocytes cultured in three (3) types of culture media from the most to least was in the following order: FD10GFs>FD2GFs>FD. Following growth kinetics analysis, we decided to use FD10GFs and FD (control) for further evaluation and 'chondrocytes-fibrin' constructs formation. Chondrocytes cultured in FD10GFs preserved the normal diploid state (2c) with no evidence of aneuploidy, haploidy or tetraploidy. Expression of cartilage-specific markers namely collagen type II, aggrecan core protein and sox-9 were significantly higher in FD10GFs when compared to control. After implantation, 'chondrocytes-fibrin' constructs exhibited firm, white, smooth and glistening cartilage-like properties. FD10GFs constructs formed better quality cartilage-like tissue than FD constructs in term of overall cartilaginous tissue formation, cells organization and extracellular matrix distribution in the specimens. Cartilaginous tissue formation was confirmed by the presence of lacunae and cartilage-isolated cells embedded within basophilic ground substance. Presence of proteoglycan was confirmed by positive Safranin O staining. Collagen type II exhibited immunopositivity at the pericellular and inter-territorial matrix area. Chondrogenic properties of the construct were further confirmed by the expression of genes encoding collagen type II, aggrecan core protein and sox9. In conclusion, FD10GFs promotes the proliferation of chondrocytes and formation of good quality 'chondrocytes-fibrin' constructs which may have potential use of matrix-induced cell implantation.
    Matched MeSH terms: Culture Media/pharmacology
  8. Expression of the Na+/H+ antiporter gene (g1-nhaC) of alkaliphilic Bacillus sp. G1 in Escherichia coli
    Liew CW, Illias RM, Mahadi NM, Najimudin N
    FEMS Microbiol Lett, 2007 Nov;276(1):114-22.
    PMID: 17937670
    A Na(+)/H(+) antiporter gene was isolated from alkaliphilic Bacillus sp. G1. The full-length sequence of the Na(+)/H(+) antiporter gene was obtained using a genome walking method, and designated as g1-nhaC. An ORF preceded by a promoter-like sequence and a Shine-Dalgarno sequence, and followed by a terminator-like sequence was identified. The deduced amino acid sequence consists of 535 amino acids, and a calculated molecular mass of 57 776 Da. g1-nhaC was subsequently cloned into pET22b(+) and expressed in Escherichia coli BL21 (DE3). Recombinant E. coli harboring the g1-nhaC gene was able to grow in modified L medium at various concentrations of NaCl (0.2-2.0 M) at different pH values. The recombinant bacteria grew well in the medium with concentrations of NaCl as high as 1.75 M at pH 8.0-9.0. Minimal growth was observed at 2.0 M NaCl, pH 8.0-9.0. At pH 10, the recombinant bacteria grew well in a medium with a low concentration of NaCl (0.2 M). These results suggested that the g1-NhaC antiporter from Bacillus sp. G1 plays a role in Na(+) extrusion at lower pH values and in pH homeostasis at pH 10 under Na(+)-limiting conditions.
    Matched MeSH terms: Culture Media/chemistry
  9. S5 Lipase: an organic solvent tolerant enzyme
    Rahman RN, Baharum SN, Salleh AB, Basri M
    J Microbiol, 2006 Dec;44(6):583-90.
    PMID: 17205035
    In this study, an organic solvent tolerant bacterial strain was isolated. This strain was identified as Pseudomonas sp. strain S5, and was shown to degrade BTEX (Benzene, Toluene, Ethyl-Benzene, and Xylene). Strain S5 generates an organic solvent-tolerant lipase in the late logarithmic phase of growth. Maximum lipase production was exhibited when peptone was utilized as the sole nitrogen source. Addition of any of the selected carbon sources to the medium resulted in a significant reduction of enzyme production. Lower lipase generation was noted when an inorganic nitrogen source was used as the sole nitrogen source. This bacterium hydrolyzed all tested triglycerides and the highest levels of production were observed when olive oil was used as a natural triglyceride. Basal medium containing Tween 60 enhanced lipase production to the most significant degree. The absence of magnesium ions (Mg2+) in the basal medium was also shown to stimulate lipase production. Meanwhile, an alkaline earth metal ion, Na+, was found to stimulate the production of S5 lipase.
    Matched MeSH terms: Culture Media/chemistry
  10. Identification of novel extracellular protein for PCB/biphenyl metabolism in Rhodococcus jostii RHA1
    Atago Y, Shimodaira J, Araki N, Bin Othman N, Zakaria Z, Fukuda M, et al.
    Biosci Biotechnol Biochem, 2016 May;80(5):1012-9.
    PMID: 26828632 DOI: 10.1080/09168451.2015.1127134
    Rhodococcus jostii RHA1 (RHA1) degrades polychlorinated biphenyl (PCB) via co-metabolism with biphenyl. To identify the novel open reading frames (ORFs) that contribute to PCB/biphenyl metabolism in RHA1, we compared chromatin immunoprecipitation chip and transcriptomic data. Six novel ORFs involved in PCB/biphenyl metabolism were identified. Gene deletion mutants of these 6 ORFs were made and were tested for their ability to grow on biphenyl. Interestingly, only the ro10225 deletion mutant showed deficient growth on biphenyl. Analysis of Ro10225 protein function showed that growth of the ro10225 deletion mutant on biphenyl was recovered when exogenous recombinant Ro10225 protein was added to the culture medium. Although Ro10225 protein has no putative secretion signal sequence, partially degraded Ro10225 protein was detected in conditioned medium from wild-type RHA1 grown on biphenyl. This Ro10225 fragment appeared to form a complex with another PCB/biphenyl oxidation enzyme. These results indicated that Ro10225 protein is essential for the formation of the PCB/biphenyl dioxygenase complex in RHA1.
    Matched MeSH terms: Culture Media, Conditioned/chemistry
  11. Stemness and angiogenic gene expression changes of serial-passage human amnion mesenchymal cells
    Fatimah SS, Tan GC, Chua K, Fariha MM, Tan AE, Hayati AR
    Microvasc Res, 2013 Mar;86:21-9.
    PMID: 23261754 DOI: 10.1016/j.mvr.2012.12.004
    Particular attention has been directed towards human amnion mesenchymal stem cells (HAMCs) due to their accessibility, availability and immunomodulatory properties. Therefore, the aim of the present study was to determine the temporal changes of stemness and angiogenic gene expressions of serial-passage HAMCs.
    Matched MeSH terms: Culture Media/pharmacology
  12. Fulltext Optimization of the expression of surface antigen SAG1/2 of Toxoplasma gondii in the yeast Pichia pastoris
    Thiruvengadam G, Init I, Fong MY, Lau YL
    Trop Biomed, 2011 Dec;28(3):506-13.
    PMID: 22433878 MyJurnal
    Surface antigens are the most abundant proteins found on the surface of the parasite Toxoplasma gondii. Surface antigen 1 (SAG1) and Surface antigen 2 (SAG2) remain the most important and extensively studied surface proteins. These antigens have been identified to play a role in host cell invasion, immune modulation, virulence attenuation. Recombinant SAG1/2 was cloned and expressed in yeast Pichia pastoris. We describe here optimization of critical parameters involved in high yield expression of the recombinant SAG1/2. Our results suggest that recombinant SAG1/2 were best expressed at 30ºC, pH 6 and 1% methanol as the carbon source by X33 Pichia cells. Additional optimizations included the downstream process such as ammonium sulphate precipitation and dialysis. The fusion protein was purified using Ni-NTA purification system with 80% recovery. The purified protein was 100% specific and sensitive in detection of toxoplasmosis.
    Matched MeSH terms: Culture Media/chemistry
  13. Improvement of isolated caprine islet survival and functionality in vitro by enhancing of PDX1 gene expression
    Hani H, Allaudin ZN, Mohd-Lila MA, Sarsaifi K, Rasouli M, Tam YJ, et al.
    Xenotransplantation, 2017 05;24(3).
    PMID: 28397308 DOI: 10.1111/xen.12302
    BACKGROUND: Dead islets replaced with viable islets are a promising offer to restore normal insulin production to a person with diabetes. The main reason for establishing a new islet source for transplantation is the insufficiency of human donor pancreas while using xenogeneic islets perhaps assists this problem. The expression of PDX1 is essential for the pancreas expansion. In mature β-cells, PDX1 has several critical roles such as glucose sensing, insulin synthesis, and insulin secretion. In this study, we aimed to evaluate the expression of pancreatic duodenal homeobox-1 (PDX1) in treated caprine islets in culture and to assess the protective effects of antioxidant factors on the PDX1 gene in cultured caprine islets.

    MATERIALS AND METHODS: Purified islets were treated with serum-free, serum, IBMX, tocopherol, or IBMX and tocopherol media. Quantitative polymerase chain reaction and Western blotting were carried out to compare the expression levels of PDX1 in treated purified islets cultured with different media.

    RESULTS: Islets treated with IBMX/tocopherol exhibited the highest fold change in the relative expression of PDX1 on day 5 post-treatment (relative expression: 6.80±2.08), whereas serum-treated islets showed the lowest fold changes in PDX1 expression on day 5 post-treatment (0.67±0.36), as compared with the expression on day 1 post-treatment. Insulin production and viability tests of purified islets showed superiority of islet at supplemented serum-free media with IBMX/tocopherol compared to other cultures (53.875%±1.59%).

    CONCLUSIONS: Our results indicated that supplemented serum-free medium with tocopherol and IBMX enhances viability and PDX1 gene expression compared to serum-added and serum-free media.

    Matched MeSH terms: Culture Media; Culture Media, Serum-Free
  14. Umbilical Cord Mesenchymal Stem Cells Conditioned Medium Promotes Aβ25-35 phagocytosis by Modulating Autophagy and Aβ-Degrading Enzymes in BV2 Cells
    Xu Z, Nan W, Zhang X, Sun Y, Yang J, Lu K, et al.
    J Mol Neurosci, 2018 Jun;65(2):222-233.
    PMID: 29845511 DOI: 10.1007/s12031-018-1075-5
    Mesenchymal stem cell (MSC) therapy is a promising prospect for the treatment of Alzheimer's disease (AD); however, the underlying mechanisms by which MSCs mediate positive effects are still unclear. We speculated that MSCs mediate microglial autophagy and enhance the clearance of Aβ. To test this hypothesis, we cultured BV2 microglial cells with umbilical cord mesenchymal stem cells conditioned medium (ucMSCs-CM) in the presence or absence of Aβ25-35 oligomers. We investigated BV2 cell proliferation, cell death, and Aβ25-35 phagocytosis as well as protein expression levels of LC3, Beclin-1, p62, insulin-degrading enzyme (IDE), and neprilysin (Nep) with western blotting. The results showed that ucMSCs-CM inhibited the proliferation and decreased cell death of BV2 cells induced by Aβ25-35. ucMSCs-CM also promoted the phagocytosis of Aβ25-35 by BV2 cells and changed the expression of autophagy-related proteins LC3, Beclin-1, and p62. Treatment also upregulated the expression of Aβ-degrading enzymes IDE and Nep. Furthermore, the culture medium in BV2 cells with Aβ25-35 and ucMSCs-CM prevented neuronal cell SH-SY5Y from cell death compared to control medium without ucMSCs-CM. Altogether, these data suggested that ucMSCs-CM protect microglial and neuronal cells from Aβ25-35-induced cell death and promote Aβ phagocytosis by modulating autophagy and enhancing the expression of Aβ-degrading enzymes in microglia.
    Matched MeSH terms: Culture Media, Conditioned/pharmacology
  15. Guided evaluation and standardisation of mesenchymal stem cell culture conditions to generate conditioned medium favourable to cardiac c-kit cell growth
    Ng WH, Umar Fuaad MZ, Azmi SM, Leong YY, Yong YK, Ng AMH, et al.
    Cell Tissue Res, 2019 Feb;375(2):383-396.
    PMID: 30232595 DOI: 10.1007/s00441-018-2918-7
    Mesenchymal stem cells (MSCs) are known to secrete cardioprotective paracrine factors that can potentially activate endogenous cardiac c-kit cells (CCs). This study aims to optimise MSC growth conditions and medium formulation for generating the conditioned medium (CdM) to facilitate CC growth and expansion in vitro. The quality of MSC-CdM after optimisation of seeding density during MSC stabilisation and medium formulation used during MSC stimulation including glucose, ascorbic acid, serum and oxygen levels and the effects of treatment concentration and repeated CdM harvesting were assessed based on CC viability in vitro under growth factor- and serum-deprived condition. Our data showed that functional CdM can be produced from MSCs with a density of 20,000 cells/cm2, which were stimulated using high glucose (25 mM), ascorbic acid supplemented, serum-free medium under normoxic condition. The generated CdM, when applied to growth factor- and serum-deprived medium at 1:1 ratio, improved CC viability, migration and proliferation in vitro. Such an effect could further be augmented by generating CdM concentrates without compromising CC gene and protein expressions, while retaining its capability to undergo differentiation to form endothelial, smooth muscle and cardiomyocytes. Nevertheless, CdM could not be repeatedly harvested from the same MSC culture, as the protein content and its effect on CC viability deteriorated after the first harvest. In conclusion, this study provides a proof-of-concept strategy to standardise the production of CdM from MSCs based on rapid, stepwise assessment of CC viability, thus enabling production of CdM favourable to CC growth for in vitro or clinical applications.
    Matched MeSH terms: Culture Media, Conditioned/pharmacology*
  16. The NLRP3 inflammasome is involved in the neuroprotective mechanism of neural stem cells against microglia-mediated toxicity in SH-SY5Y cells via the attenuation of tau hyperphosphorylation and amyloidogenesis
    Chan EWL, Krishnansamy S, Wong C, Gan SY
    Neurotoxicology, 2019 01;70:91-98.
    PMID: 30408495 DOI: 10.1016/j.neuro.2018.11.001
    The cognitive impairment caused by Alzheimer's disease (AD) is associated with beta-amyloid (Aβ) and tau proteins, and is accompanied by inflammation. Recently, a novel inflammasome signaling pathway has been uncovered. Inflammasomes are implicated in the execution of inflammatory responses and pyroptotic death leading to neurodegeneration. Thus, the inflammasome signaling pathway could be a potential therapeutic target for AD. Neural stem cells (NSCs) are multipotent cells that can self-renew and differentiate into distinct neural cells. NSC therapy has been considered to be a promising therapeutic approach in protecting the central nervous system and restoring it following damage. However, the mechanisms involved remain unclear. The aims of this study were to investigate the protective effects of NE4C neural stem cells against microglia-mediated neurotoxicity and to explore molecular mechanisms mediating their actions. NE4C decreased the levels of caspase-1 and IL-1β, and attenuated the level of the NLRP3 inflammasome and its associated protein adapter, apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain (ASC) in LPS-stimulated BV2 microglial cells, possibly by regulating the phosphorylation of p38α MAPK. The conditioned media obtained from co-culture of LPS-stimulated BV2 and NE4C cells exhibited protective effects on SH-SY5Y cells against microglia-mediated neurotoxicity; this was associated with an attenuation of tau phosphorylation and amyloidogenesis and accompanied by down-regulation of GSK-3β and p38α MAPK signalling pathways. In conclusion, the present study suggested that NSC therapy could be a potential strategy against microglia-mediated neurotoxicity. NSCs regulate NLRP3 activation and IL-1β secretion, which are critical in the initiation of the inflammatory responses, hence preventing the release of neurotoxic pro-inflammatory factors by microglia. This eventually reduces tau hyperphosphylation and amyloidogenesis, possibly through the regulation of GSK-3β and p38α MAPK signalling pathways, and thus protects SH-SY5Y cells against microglia-mediated neurotoxicity.
    Matched MeSH terms: Culture Media, Conditioned/pharmacology
  17. Fulltext Antimicrobial activities of Bacillus velezensis strains isolated from stingless bee products against methicillin-resistant Staphylococcus aureus
    Baharudin MMA, Ngalimat MS, Mohd Shariff F, Balia Yusof ZN, Karim M, Baharum SN, et al.
    PLoS One, 2021;16(5):e0251514.
    PMID: 33974665 DOI: 10.1371/journal.pone.0251514
    Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) have reached epidemic proportions globally. Therefore, there is an urgent need for a continuous supply of antibiotics to combat the problem. In this study, bacteria initially identified as species belonging to the Bacillus amyloliquefaciens operational group were re-identified based on the housekeeping gene, gyrB. Cell-free supernatants (CFS) from the strains were used for antimicrobial tests using the agar well diffusion assay against MRSA and various types of pathogenic bacteria. The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and physicochemical characteristics of the CFS were determined. Based on gyrB sequence analysis, five strains (PD9, B7, PU1, BP1 and L9) were identified as Bacillus velezensis. The CFS of all B. velezensis strains showed broad inhibitory activities against Gram-negative and -positive as well as MRSA strains. Strain PD9 against MRSA ATCC 33742 was chosen for further analysis as it showed the biggest zone of inhibition (21.0 ± 0.4 mm). The MIC and MBC values obtained were 125 μl/ml. The crude antimicrobial extract showed bactericidal activity and was stable at various temperatures (40-80°C), pH (4-12), surfactants (Tween 20, Tween 80, SDS and Triton X-100) and metal ions (MgCI2, NaCI2, ZnNO3 and CuSO4) when tested. However, the crude extract was not stable when treated with proteinase K. All these properties resembled the characteristics of peptides. The antimicrobial compound from the selected strain was purified by using solvent extraction method and silica gel column chromatography. The purified compound was subjected to High Performance Liquid Chromatography which resulted in a single peak of the anti-MRSA compound being detected. The molecular weight of the anti-MRSA compound was determined by using SDS-PAGE and zymogram. The size of the purified antimicrobial peptide was approximately ~ 5 kDa. The antimicrobial peptide produced from B. velezensis strain PD9 is a promising alternative to combat the spread of MRSA infections in the future.
    Matched MeSH terms: Culture Media, Conditioned/pharmacology
  18. Benchtop Isolation and Characterisation of Small Extracellular Vesicles from Human Mesenchymal Stem Cells
    Tan KL, Chia WC, How CW, Tor YS, Show PL, Looi QHD, et al.
    Mol Biotechnol, 2021 Sep;63(9):780-791.
    PMID: 34061307 DOI: 10.1007/s12033-021-00339-2
    The objective of this study is to develop a simple protocol to isolate and characterise small extracellular vesicles (sEVs) from human umbilical cord-derived MSCs (hUC-MSCs). hUC-MSCs were characterised through analysis of morphology, immunophenotyping and multidifferentiation ability. SEVs were successfully isolated by ultrafiltration from the conditioned medium of hUC-MSCs. The sEVs' size distribution, intensity within a specific surface marker population were measured with zetasizer or nanoparticle tracking analysis. The expression of surface and internal markers of sEVs was also assessed by western blotting. Morphology of hUC-MSCs displayed as spindle-shaped, fibroblast-like adherent cells. Phenotypic analysis by flow cytometry revealed that hUC-MSCs expressed MSC surface marker, including CD90, CD73, CD105, CD44 and exhibited the capacity for osteogenic, adipogenic and chondrogenic differentiation. Populations of sEVs with CD9, CD63 and CD81 positive were detected with size distribution in the diameter of 63.2 to 162.5 nm. Typical sEVs biomarkers such as CD9, CD63, CD81, HSP70 and TSG101 were also detected with western blotting. Our study showed that sEVs from hUC-MSCs conditioned medium were successfully isolated and characterised. Downstream application of hUC-MSCs-sEVs will be further explored.
    Matched MeSH terms: Culture Media, Conditioned/chemistry
  19. Fulltext A Fatal Case of Candida auris and Candida tropicalis Candidemia in Neutropenic Patient
    Mohd Tap R, Lim TC, Kamarudin NA, Ginsapu SJ, Abd Razak MF, Ahmad N, et al.
    Mycopathologia, 2018 Jun;183(3):559-564.
    PMID: 29383574 DOI: 10.1007/s11046-018-0244-y
    We report a fatal case of Candida auris that was involved in mixed candidemia with Candida tropicalis, isolated from the blood of a neutropenic patient. Identification of both isolates was confirmed by amplification and sequencing of internal transcribed spacer and D1/D2 domain of large subunit in rRNA gene. Antifungal susceptibility test by E-test method revealed that C. auris was resistant to amphotericin B, anidulafungin, caspofungin, fluconazole, itraconazole and voriconazole. On the other hand, C. tropicalis was sensitive to all antifungal tested. The use of chromogenic agar as isolation media is vital in detecting mixed candidemia.
    Matched MeSH terms: Culture Media/chemistry
  20. Synthesis of geranyl propionate in a solvent-free medium using Rhizomucor miehei lipase covalently immobilized on chitosan-graphene oxide beads
    Isah AA, Mahat NA, Jamalis J, Attan N, Zakaria II, Huyop F, et al.
    Prep Biochem Biotechnol, 2017 Feb 07;47(2):199-210.
    PMID: 27341522 DOI: 10.1080/10826068.2016.1201681
    The chemical route of producing geranyl propionate involves the use of toxic chemicals, liberation of unwanted by-products as well as problematic separation process. In view of such problems, the use of Rhizomucor miehei lipase (RML) covalently bound onto activated chitosan-graphene oxide (RML-CS/GO) support is suggested. Following analyses using Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and thermogravimetry, properties of the RML-CS/GO were characterized. A response surface methodological approach using a 3-level-four-factor (incubation time, temperature, substrate molar ratio, and stirring rate) Box-Behnken design was used to optimize the experimental conditions to maximize the yield of geranyl propionate. Results revealed that 76 ± 0.02% of recovered protein had yielded 7.2 ± 0.04 mg g(-1) and 211 ± 0.3% U g(-1) of the maximum protein loading and esterification activity, respectively. The actual yield of geranyl propionate (49.46%) closely agreed with the predicted value (49.97%) under optimum reaction conditions (temperature: 37.67°C, incubation time: 10.20 hr, molar ratio (propionic acid:geraniol): 1:3.28, and stirring rate: 100.70 rpm) and hence, verifying the suitability of this approach. Since the method is performed under mild conditions, the RML-CS/GO biocatalyst may prove to be an environmentally benign alternative for producing satisfactory yield of geranyl propionate.
    Matched MeSH terms: Culture Media
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