Displaying publications 641 - 660 of 1608 in total

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  1. Chan MK, Lim SK, Miswan N, Chew AL, Noordin R, Khoo BY
    Protein Expr Purif, 2018 Jan;141:52-62.
    PMID: 28893606 DOI: 10.1016/j.pep.2017.09.003
    This study described the isolation of the coding region of human topoisomerase I (TopoI) from MDA-MB-231 and the expression of multiple copy recombinant genes in four Pichia pastoris strains. First, polymerase chain reaction (PCR)-amplification of the enzyme coding region was performed. The PCR fragment was cloned into pPICZ-α-A vector and sequenced. It was then transformed into X33, GS115, SMD1168H and KM71H strains of Pichia. PCR-screening for positive clones was performed, and estimation of multiple copy integrants in each Pichia strain was carried out using agar plates containing increasing concentrations of Zeocin(®). The selected clones of multiple copy recombinant genes were then induced for TopoI expression in shaker flasks. GS115 and SMD1168 were found to be better Pichia strains to accommodate the recombinant gene for the expression of TopoI extracellularly. However, the DNA relaxation activity revealed that only the target enzyme in the culture supernatants of GS115-pPICZ-α-A-TopoI exhibited consistent enzyme activity over the cultivation time-points. Active enzyme activity was inhibited by Camptothecin. The enzyme produced can be used for in-house gel-based DNA relaxation assay development in performing high throughput screening for target-specific growth inhibitors that display similar effect as the TopoI inhibitors. These inhibitors may contribute to the improvement of the treatment of cancer patients.
    Matched MeSH terms: Recombinant Proteins/genetics
  2. Barloy F, Delécluse A, Nicolas L, Lecadet MM
    J Bacteriol, 1996 Jun;178(11):3099-105.
    PMID: 8655486
    A gene (cbm71) encoding a 71,128-Da mosquitocidal protein (Cbm71) was obtained by screening a size-fractionated XbaI digest of total genomic DNA from Clostridium bifermentans subsp. malaysia CH18 with two gene-specific oligonucleotide probes. The sequence of the Cbm71 protein, as deduced from the sequence of cbm71, corresponds to that of the 66-kDa protein previously described as one of the mosquitocidal components of C. bifermentans subsp. malaysia. Cbm71 shows limited similarities with Bacillus thuringiensis delta-endotoxins, especially in the four first conserved blocks. However, Cbm71 was not immunologically related to any of the Cry toxins and thus belongs to a novel class of mosquitocidal protein. The cbm71 gene was expressed in a nontoxic strain of B. thuringiensis, and Cbm71 was produced during sporulation and secreted to the supernatant of culture. Trichloroacetic-precipitated supernatant preparations were toxic for mosquito larvae of the species Aedes aegypti, Culex pipiens, and Anopheles stephensi.
    Matched MeSH terms: Bacterial Proteins/genetics*
  3. Chen H, Cao S, Chen J, Wang H, Wei Y, Chen Y, et al.
    J Plant Physiol, 2024 Sep;300:154297.
    PMID: 38945071 DOI: 10.1016/j.jplph.2024.154297
    Programmed cell death (PCD) is a genetically regulated process of cell suicide essential for plant development. The 'malate valve' is a mechanism that ensures redox balance across different subcellular compartments. In broccoli, the BomMDH1 gene encodes malate dehydrogenase in mitochondria, a critical enzyme in the 'malate circulation' pathway. This study investigates the functional role of BomMDH1 in malate (MA)-induced apoptosis in bright yellow-2 (BY-2) suspension cells. Findings revealed that transgenic cells overexpressing BomMDH1 showed enhanced viability under MA-induced oxidative stress compared to wild-type (WT) cells. Overexpression of BomMDH1 also reduced levels of reactive oxygen species (ROS), hydrogen peroxide (H2O2), and malondialdehyde (MDA), while increasing the expression of antioxidant enzyme genes such as NtAPX, NtAOX1a, NtSOD, and NtMDHAR. Additionally, treatment with salicylhydroxamic acid (SHAM), a characteristic inhibitor of mitochondrial respiration, further improved the anti-apoptotic activity of BY-2 cells. Overall, these results highlighted the function of the BomMDH1 gene and the potential of SHAM treatment in mitigating oxidative stress in BY-2 suspension cells.
    Matched MeSH terms: Plant Proteins/genetics
  4. Jensen KS, Adams R, Bennett RS, Bernbaum J, Jahrling PB, Holbrook MR
    PLoS One, 2018;13(6):e0199534.
    PMID: 29920552 DOI: 10.1371/journal.pone.0199534
    Nipah virus (NiV) is a highly pathogenic zoonotic paramyxovirus that can result in severe pulmonary disease and fatal encephalitis in humans and is responsible for outbreaks in Bangladesh, Malaysia, Singapore, India and possibly the Philippines. NiV has a negative-sense RNA genome that contains six genes and serves as a template for production of viral mRNA transcripts. NiV mRNA transcripts are subsequently translated into viral proteins. Traditionally, NiV quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR) assays have relied on using primer sets that amplify a target (N that encodes the nucleocapsid) within the coding region of the viral gene that also amplifies viral mRNA. Here we describe a novel one-step qRT-PCR assay targeting the intergenic region separating the viral F and G proteins, thereby eliminating amplification of the viral mRNA. This assay is more accurate than the traditional qRT-PCR in quantifying concentrations of viral genomic RNA.
    Matched MeSH terms: Viral Proteins/genetics
  5. Lim SJ, Noor NDM, Sabri S, Ali MSM, Salleh AB, Oslan SN
    Microb Pathog, 2024 Aug;193:106773.
    PMID: 38960213 DOI: 10.1016/j.micpath.2024.106773
    Meyerozyma guilliermondii (Candida guilliermondii) is one of the Candida species associated with invasive candidiasis. With the potential for expressing industrially important enzymes, M. guilliermondii strain SO possessed 99 % proteome similarity with the clinical ATCC 6260 isolate and showed pathogenicity towards zebrafish embryos. Recently, three secreted aspartyl proteinases (SAPs) were computationally identified as potential virulence factors in this strain without in vitro verification of SAP activity. The quantification of Candida SAPs activity in liquid broth were also scarcely reported. Thus, this study aimed to characterize M. guilliermondii strain SO's ability to produce SAPs (MgSAPs) in different conditions (morphology and medium) besides analyzing its growth profile. MgSAPs' capability to cleave bovine serum albumin (BSA) was also determined to propose that MgSAPs as the potential virulence factors compared to the avirulent Saccharomyces cerevisiae. M. guilliermondii strain SO produced more SAPs (higher activity) in yeast nitrogen base-BSA-dextrose broth compared to yeast extract-BSA-dextrose broth despite insignificantly different SAP activity in both planktonic and biofilm cells. FeCl3 supplementation significantly increased the specific protein activity (∼40 %). The BSA cleavage by MgSAPs at an acidic pH was proven through semi-quantitative SDS-PAGE, sharing similar profile with HIV-1 retropepsin. The presented work highlighted the MgSAPs on fungal cell wall and extracellular milieu during host infection could be corroborated to the quantitative production in different growth modes presented herein besides shedding lights on the potential usage of retropepsin's inhibitors in treating candidiasis. Molecular and expression analyses of MgSAPs and their deletion should be further explored to attribute their respective virulence effects.
    Matched MeSH terms: Fungal Proteins/genetics
  6. Li Z, Gopinath SCB, Lakshmipriya T, Anbu P, Perumal V, Wang X
    Biomed Microdevices, 2020 Sep 17;22(4):67.
    PMID: 32940771 DOI: 10.1007/s10544-020-00522-3
    Nanoscale materials have been employed in the past 2 decades in applications such as biosensing, therapeutics and medical diagnostics due to their beneficial optoelectronic properties. In recent years, silver nanoparticles (AgNPs) have gained attention due to their higher plasmon excitation efficiency than gold nanoparticles, as proved by sharper and stronger plasmon resonance peaks. The current work is focused on utilizing self-assembled DNA-AgNPs on microdevices for the detection of gynecological cancers. Human papilloma virus (HPV) mostly spreads through sexual transmittance and can cause various gynecological cancers, including cervical, ovarian and endometrial cancers. In particular, oncogene E7 from the HPV strain 16 (HPV-16 E7) is responsible for causing these cancers. In this research, the target sequence of HPV-16 E7 was detected by an AgNP-conjugated capture probe on a dielectrode sensor. The detection limit was in the range between 10 and 100 aM (by 3σ estimation). The sensitivity of the AgNP-conjugated probe was 10 aM and similar to the sensitivity of gold nanoparticle conjugation sensors, and the mismatched control DNA failed to detect the target, proving selective HPV detection. Morphological assessments on the AgNPs and the sensing surfaces by high-resolution microscopy revealed the surface arrangement. This sensing platform can be expanded to develop sensors for the detection various clinically relevant targets.
    Matched MeSH terms: Papillomavirus E7 Proteins/genetics
  7. Ishak SNH, Kamarudin NHA, Ali MSM, Leow ATC, Shariff FM, Rahman RNZRA
    PLoS One, 2021;16(6):e0251751.
    PMID: 34061877 DOI: 10.1371/journal.pone.0251751
    5M mutant lipase was derived through cumulative mutagenesis of amino acid residues (D43E/T118N/E226D/E250L/N304E) of T1 lipase from Geobacillus zalihae. A previous study revealed that cumulative mutations in 5M mutant lipase resulted in decreased thermostability compared to wild-type T1 lipase. Multiple amino acids substitution might cause structural destabilization due to negative cooperation. Hence, the three-dimensional structure of 5M mutant lipase was elucidated to determine the evolution in structural elements caused by amino acids substitution. A suitable crystal for X-ray diffraction was obtained from an optimized formulation containing 0.5 M sodium cacodylate trihydrate, 0.4 M sodium citrate tribasic pH 6.4 and 0.2 M sodium chloride with 2.5 mg/mL protein concentration. The three-dimensional structure of 5M mutant lipase was solved at 2.64 Å with two molecules per asymmetric unit. The detailed analysis of the structure revealed that there was a decrease in the number of molecular interactions, including hydrogen bonds and ion interactions, which are important in maintaining the stability of lipase. This study facilitates understanding of and highlights the importance of hydrogen bonds and ion interactions towards protein stability. Substrate specificity and docking analysis on the open structure of 5M mutant lipase revealed changes in substrate preference. The molecular dynamics simulation of 5M-substrates complexes validated the substrate preference of 5M lipase towards long-chain p-nitrophenyl-esters.
    Matched MeSH terms: Bacterial Proteins/genetics
  8. Shi T, Gao J, Xu W, Liu X, Yan B, Azra MN, et al.
    PMID: 38908544 DOI: 10.1016/j.cbpb.2024.111001
    Mannose-binding lectin (MBL) is a vital member of the lectin family, crucial for mediating functions within the complement lectin pathway. In this study, following the cloning of the mannose-binding lectin (MBL) gene in the ridgetail white prawn, Exopalaemon carinicauda, we examined its expression patterns across various tissues and its role in combating challenges posed by Vibrio parahaemolyticus. The results revealed that the MBL gene spans 1342 bp, featuring an open reading frame of 972 bp. It encodes a protein comprising 323 amino acids, with a predicted relative molecular weight of 36 kDa and a theoretical isoelectric point of 6.18. The gene exhibited expression across various tissues including the eyestalk, heart, gill, hepatopancreas, stomach, intestine, ventral nerve cord, muscle, and hemolymph, with the highest expression detected in the hepatopancreas. Upon challenge with V. parahaemolyticus, RT-PCR analysis revealed a trend of MBL expression in hepatopancreatic tissues, characterized by an initial increase followed by a subsequent decrease, peaking at 24 h post-infection. Employing RNA interference to disrupt MBL gene expression resulted in a significant increase in mortality rates among individuals challenged with V. parahaemolyticus. Furthermore, we successfully generated the Pet32a-MBL recombinant protein through the construction of a prokaryotic expression vector for conducting in vitro bacterial inhibition assays, which demonstrated the inhibitory effect of the recombinant protein on V. parahaemolyticus, laying a foundation for further exploration into its immune mechanism in response to V. parahaemolyticus challenges.
    Matched MeSH terms: Arthropod Proteins/genetics
  9. Ch'ng LS, Lee WS, Kirkwood CD
    Emerg Infect Dis, 2011 May;17(5):948-50.
    PMID: 21529427 DOI: 10.3201/eid1705.101652
    Matched MeSH terms: Capsid Proteins/genetics
  10. Tun MM, Thant KZ, Inoue S, Nabeshima T, Aoki K, Kyaw AK, et al.
    Emerg Infect Dis, 2014 Aug;20(8):1378-81.
    PMID: 25062511 DOI: 10.3201/eid2008.131431
    In 2010, chikungunya virus of the East Central South African genotype was isolated from 4 children in Myanmyar who had dengue-like symptoms. Phylogenetic analysis of the E1 gene revealed that the isolates were closely related to isolates from China, Thailand, and Malaysia that harbor the A226V mutation in this gene.
    Matched MeSH terms: Viral Proteins/genetics
  11. Ten KE, Rahman S, Tan HS
    Microb Genom, 2024 Nov;10(11).
    PMID: 39565092 DOI: 10.1099/mgen.0.001327
    Despite being a major human pathogen, limited studies have reported RNA modifications in Acinetobacter baumannii. These post-transcriptional modifications play crucial regulatory roles in bacteria and have also been shown to modulate bacterial virulence. Using nanopore sequencing, we characterized RNA modifications in a virulent A. baumannii strain (Ab-C98) under free-living (mid-exponential phase in vitro culture) and during an early stage of infection (3 h post-infection) in Galleria mellonella larvae. Analysis revealed that m5C methylations are essential for ribosome synthesis, while m6A and Ψ are involved in metabolic pathways and translation processes. Iron-chelating genes exbD (m5C and m6A) and feoB (m6A and Ψ) and RNA polymerase subunit rpoC (m6A and Ψ) were selectively modified during infection. This first transcriptome-wide study highlights the potential regulatory roles of m5C, m6A and Ψ modifications in A. baumannii during infection.
    Matched MeSH terms: Bacterial Proteins/genetics
  12. Rahmat NL, Zifruddin AN, Yusoff NS, Sulaiman S, Zainal Abidin CMR, Othman NW, et al.
    Comput Biol Chem, 2024 Oct;112:108176.
    PMID: 39181100 DOI: 10.1016/j.compbiolchem.2024.108176
    Metisa plana is a widespread insect pest infesting oil palm plantations in Malaysia. Farnesyl acetate (FA), a juvenile hormone analogue, has been reported to exert in vitro and in vivo insecticidal activity against other insect pests. However, the insecticidal mechanism of FA on M. plana remains unclear. Therefore, this study aims to elucidate responsive genes in M. plana in response to FA treatment. The RNA-sequencing reads of FA-treated M. plana were de novo-assembled with existing raw reads from non-treated third instar larvae, and 55,807 transcripts were functionally annotated to multiple protein databases. Several insecticide detoxification-related genes were differentially regulated among the 321 differentially expressed transcripts. Cytochrome P450 monooxygenase, carboxylesterase, and ATP-binding cassette protein were upregulated, while peptidoglycan recognition protein was downregulated. Innate immune response genes, such as glutathione S-transferases, acetylcholinesterase, and heat shock protein, were also identified in the transcriptome. The findings signify that changes occurred in the insect's receptor and signaling, metabolic detoxification of insecticides, and immune responses upon FA treatment on M. plana. This valuable information on FA toxicity may be used to formulate more effective biorational insecticides for better M. plana pest management strategies in oil palm plantations.
    Matched MeSH terms: Insect Proteins/genetics
  13. Shintani T, Higaki M, Rosli SNZ, Okamoto T
    In Vitro Cell Dev Biol Anim, 2024 Jun;60(6):583-589.
    PMID: 38713345 DOI: 10.1007/s11626-024-00913-3
    Heparin-binding protein 17 (HBp17), first purified in 1991 from the conditioned medium of the human A431 squamous cell carcinoma (SCC) cell line, was later renamed fibroblast growth factor-binding protein 1 (FGFBP-1). HBp17/FGFBP-1 is specifically expressed and secreted by epithelial cells, and it reversibly binds to fibroblast growth factor (FGF)-1 and FGF-2, as well as FGFs-7, -10, and -22, indicating a crucial involvement in the transportation and function of these FGFs. Our laboratory has investigated and reported several studies to elucidate the function of HBp17/FGFBP-1 in SCC cells and its potential as a molecular therapeutic target. HBp17/FGFBP-1 transgene exoression in A431-4 cells, a clonal subline of A431 that lacks tumorigenicity and does not express HBp17/FGFBP-1, demonstrated a significantly enhanced proliferation in vitro compared with A431-4 cells, and it acquired tumorigenicity in the subcutis of nude mice. Knockout (KO) of the HBp17/FGFBP-1 by genome editing significantly suppressed tumor growth, cell motility, and tumorigenicity compared with control cells. A comprehensive analysis of expressed molecules in both cell types revealed that molecules that promote epithelial cell differentiation were highly expressed in HBp17/FGFBP-1 KO cells. Additionally, we reported that 1α,25(OH)2D3 or eldecalcitol (ED-71), which is an analog of 1α,25(OH)2D3, suppresses HBp17/FGFBP-1 expression and tumor growth in vitro and in vivo by inhibiting the nuclear factor kappa-light-chain-enhancer of activated B cells signaling pathway. Here, we discuss the prospects of molecular targeted therapy targeting HBp17/FGFBP-1 with 1α,25(OH)2D3 or ED71 in SCC and oral SCC.
    Matched MeSH terms: Intercellular Signaling Peptides and Proteins/genetics
  14. Chang CH, See Too WC, Lim BH, Few LL
    Acta Parasitol, 2024 Mar;69(1):426-438.
    PMID: 38172465 DOI: 10.1007/s11686-023-00763-1
    PURPOSE: Entamoeba histolytica is one of the death-causing parasites in the world. Study on its lipid composition revealed that it is predominated by phosphatidylcholine and phosphatidylethanolamine. Further study revealed that its phosphorylated metabolites might be produced by the Kennedy pathway. Here, we would like to report on the characterizations of enzymes from this pathway that would provide information for the design of novel inhibitors against these enzymes in future.

    METHODOLOGY: E. histolytica HM-1:IMSS genomic DNA was isolated and two putative choline/ethanolamine kinase genes (EhCK1 and EhCK2) were cloned and expressed from Escherichia coli BL21 strain. Enzymatic characterizations were further carried out on the purified enzymes.

    RESULTS: EhCK1 and EhCK2 were identified from E. histolytica genome. The deduced amino acid sequences were more identical to its homologues in human (35-48%) than other organisms. The proteins were clustered as ethanolamine kinase in the constructed phylogeny tree. Sequence analysis showed that they possessed all the conserved motifs in choline kinase family: ATP-binding loop, Brenner's phosphotransferase motif, and choline kinase motif. Here, the open reading frames were cloned, expressed, and purified to apparent homogeneity. EhCK1 showed activity with choline but not ethanolamine. The biochemical characterization showed that it had a Vmax of 1.9 ± 0.1 µmol/min/mg. Its Km for choline and ATP was 203 ± 26 µM and 3.1 ± 0.4 mM, respectively. In contrast, EhCK2 enzymatic activity was only detected when Mn2+ was used as the co-factor instead of Mg2+ like other choline/ethanolamine kinases. Highly sensitive and specific antibody against EhCK1 was developed and used to confirm the endogenous EhCK1 expression using immunoblotting.

    CONCLUSIONS: With the understanding of EhC/EK importance in phospholipid metabolism and their unique characteristic, EhC/EK could be a potential target for future anti-amoebiasis study.

    Matched MeSH terms: Protozoan Proteins/genetics
  15. Kuah MK, Jaya-Ram A, Shu-Chien AC
    Biochim. Biophys. Acta, 2015 Mar;1851(3):248-60.
    PMID: 25542509 DOI: 10.1016/j.bbalip.2014.12.012
    The endogenous production of long-chain polyunsaturated fatty acids (LC-PUFA) in carnivorous teleost species inhabiting freshwater environments is poorly understood. Although a predatory lifestyle could potentially supply sufficient LC-PUFA to satisfy the requirements of these species, the nutrient-poor characteristics of the freshwater food web could impede this advantage. In this study, we report the cloning and functional characterisation of an elongase enzyme in the LC-PUFA biosynthesis pathway from striped snakehead (Channa striata), which is a strict freshwater piscivore that shows high deposition of LC-PUFA in its flesh. We also functionally characterised a previously isolated fatty acyl desaturase cDNA from this species. Results showed that the striped snakehead desaturase is capable of Δ4 and Δ5 desaturation activities, while the elongase showed the characteristics of Elovl5 elongases. Collectively, these findings reveal that striped snakehead exhibits the genetic resources to synthesise docosahexaenoic acid (DHA; 22:6n-3) from eicosapentaenoic acid (EPA; 20:5n-3). Both genes are expressed at considerable levels in the brain and the liver. In liver, both genes were up-regulated by dietary C18 PUFA, although this increase did not correspond to a significant rise in the deposition of muscle LC-PUFA. Brain tissue of fish fed with plant oil diets showed higher expression of fads2 gene compared to fish fed with fish oil-based diet, which could ensure DHA levels remain constant under limited dietary DHA intake. This suggests the importance of DHA production from EPA via the ∆4 desaturation step in order to maintain an optimal reserve of DHA in the neuronal tissues of carnivores.
    Matched MeSH terms: Recombinant Proteins/genetics; Fish Proteins/genetics
  16. Hartanto FK, Karen-Ng LP, Vincent-Chong VK, Ismail SM, Mustafa WM, Abraham MT, et al.
    Asian Pac J Cancer Prev, 2015;16(3):953-8.
    PMID: 25735388
    BACKGROUND: Expression of KRT13, FAIM2 and CYP2W1 appears to be influenced by risk habits, thus exploring the associations of these genes in oral squamous cell cancer (OSCC) with risk habits, clinico-pathological parameters and patient survival may be beneficial in identifying relevant biomarkers with different oncogenic pathways.

    MATERIALS AND METHODS: cDNAs from 41 OSCC samples with and without risk habits were included in this study. Quantitative real-time PCR was used to analyze KRT13, FAIM2 and CYP2W1 in OSCC. The housekeeping gene (GAPDH) was used as an endogenous control.

    RESULTS: Of the 41 OSCC samples, KRT13 was down-regulated in 40 samples (97.6%), while FAIM2 and CYP2W1 were down-regulated in 61.0% and 48.8%, respectively. Overall, there were no associations between KRT13, FAIM2 and CYP2W1 expression with risk habits, selected socio-demographic and clinico-pathological parameters and patient survival.

    CONCLUSIONS: Although this study was unable to show significance, there were some tendencies in the associations of KRT13, FAIM2 and CYP2W1 expression in OSCC with selected clinic-pathological parameters and survival.

    Matched MeSH terms: Membrane Proteins/genetics*; Apoptosis Regulatory Proteins/genetics*
  17. Hasima N, Ozpolat B
    Cell Death Dis, 2014;5:e1509.
    PMID: 25375374 DOI: 10.1038/cddis.2014.467
    Autophagy, a lysosomal degradation pathway for cellular constituents and organelles, is an adaptive and essential process required for cellular homeostasis. Although autophagy functions as a survival mechanism in response to cellular stressors such as nutrient or growth factor deprivation, it can also lead to a non-apoptotic form of programmed cell death (PCD) called autophagy-induced cell death or autophagy-associated cell death (type II PCD). Current evidence suggests that cell death through autophagy can be induced as an alternative to apoptosis (type I PCD), with therapeutic purpose in cancer cells that are resistant to apoptosis. Thus, modulating autophagy is of great interest in cancer research and therapy. Natural polyphenolic compounds that are present in our diet, such as rottlerin, genistein, quercetin, curcumin, and resveratrol, can trigger type II PCD via various mechanisms through the canonical (Beclin-1 dependent) and non-canonical (Beclin-1 independent) routes of autophagy. The capacity of these compounds to provide a means of cancer cell death that enhances the effects of standard therapies should be taken into consideration for designing novel therapeutic strategies. This review focuses on the autophagy- and cell death-inducing effects of these polyphenolic compounds in cancer.
    Matched MeSH terms: Membrane Proteins/genetics; Apoptosis Regulatory Proteins/genetics
  18. Ranjani V, Janeček S, Chai KP, Shahir S, Abdul Rahman RN, Chan KG, et al.
    Sci Rep, 2014 Jul 28;4:5850.
    PMID: 25069018 DOI: 10.1038/srep05850
    The α-amylases from Anoxybacillus species (ASKA and ADTA), Bacillus aquimaris (BaqA) and Geobacillus thermoleovorans (GTA, Pizzo and GtamyII) were proposed as a novel group of the α-amylase family GH13. An ASKA yielding a high percentage of maltose upon its reaction on starch was chosen as a model to study the residues responsible for the biochemical properties. Four residues from conserved sequence regions (CSRs) were thus selected, and the mutants F113V (CSR-I), Y187F and L189I (CSR-II) and A161D (CSR-V) were characterised. Few changes in the optimum reaction temperature and pH were observed for all mutants. Whereas the Y187F (t1/2 43 h) and L189I (t1/2 36 h) mutants had a lower thermostability at 65°C than the native ASKA (t1/2 48 h), the mutants F113V and A161D exhibited an improved t1/2 of 51 h and 53 h, respectively. Among the mutants, only the A161D had a specific activity, k(cat) and k(cat)/K(m) higher (1.23-, 1.17- and 2.88-times, respectively) than the values determined for the ASKA. The replacement of the Ala-161 in the CSR-V with an aspartic acid also caused a significant reduction in the ratio of maltose formed. This finding suggests the Ala-161 may contribute to the high maltose production of the ASKA.
    Matched MeSH terms: Bacterial Proteins/genetics; Recombinant Proteins/genetics
  19. Cheah PL, Looi LM, Teoh KH, Rahman NA, Wong LX, Tan SY
    Asian Pac J Cancer Prev, 2014;15(7):3287-91.
    PMID: 24815484
    BACKGROUND: The interesting preponderance of Chinese with colorectal carcinoma (CRC) amongst the three major ethnic groups in Malaysia prompted a study to determine DNA mismatch repair (MMR) status in our CRC and attempt correlation with patient age, gender and ethnicity as well as location, grade, histological type and stage of tumour. Histologically re-confirmed CRC, diagnosed between 1st January 2005 and 31st December 2007 at the Department of Pathology, University of Malaya Medical Centre, were immunohistochemically stained with monoclonal antibodies to MMR proteins, MLH1, MSH2, MSH6 and PMS2 on the Ventana Benchmark XT autostainer. Of the 142 CRC cases entered into the study, there were 82 males and 60 females (M:F=1.4:1). Ethnically, 81 (57.0%) were Chinese, 32 (22.5%) Malays and 29 (20.4%) Indians. The patient ages ranged between 15-87 years (mean=62.4 years) with 21 cases <50-years and 121 ≥50-years of age. 14 (9.9%) CRC showed deficient MMR (dMMR). Concurrent loss of MLH1 and PMS2 occurred in 10, MSH2 and MSH6 in 2 with isolated loss of MSH6 in 1 and PMS2 in 1. dMMR was noted less frequently amongst the Chinese (6.2%) in comparison with their combined Malay and Indian counterparts (14.8%), and was associated with right sided and poorly differentiated tumours (p<0.05). 3 of the 5 (60.0%) dMMR CRC cases amongst the Chinese and 1 of 9 cases (11.1%) amongst the combined Malay and Indian group were <50-years of age. No significant association of dMMR was noted with patient age and gender, tumour stage or mucinous type.
    Matched MeSH terms: DNA-Binding Proteins/genetics; Nuclear Proteins/genetics
  20. Goulter RM, Taran E, Gentle IR, Gobius KS, Dykes GA
    Colloids Surf B Biointerfaces, 2014 Jul 1;119:90-8.
    PMID: 24880987 DOI: 10.1016/j.colsurfb.2014.04.003
    The role of Escherichia coli H antigens in hydrophobicity and attachment to glass, Teflon and stainless steel (SS) surfaces was investigated through construction of fliC knockout mutants in E. coli O157:H7, O1:H7 and O157:H12. Loss of FliC(H12) in E. coli O157:H12 decreased attachment to glass, Teflon and stainless steel surfaces (p<0.05). Complementing E. coli O157:H12 ΔfliC(H12) with cloned wildtype (wt) fliC(H12) restored attachment to wt levels. The loss of FliCH7 in E. coli O157:H7 and O1:H7 did not always alter attachment (p>0.05), but complementation with cloned fliC(H12), as opposed to cloned fliCH7, significantly increased attachment for both strains compared with wt counterparts (p<0.05). Hydrophobicity determined using bacterial adherence to hydrocarbons and contact angle measurements differed with fliC expression but was not correlated to the attachment to materials included in this study. Purified FliC was used to functionalise silicone nitride atomic force microscopy probes, which were used to measure adhesion forces between FliC and substrates. Although no significant difference in adhesion force was observed between FliC(H12) and FliCH7 probes, differences in force curves suggest different mechanism of attachment for FliC(H12) compared with FliCH7. These results indicate that E. coli strains expressing flagellar H12 antigens have an increased ability to attach to certain abiotic surfaces compared with E. coli strains expressing H7 antigens.
    Matched MeSH terms: Recombinant Proteins/genetics; Escherichia coli Proteins/genetics
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