Displaying publications 21 - 40 of 41 in total

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  1. Enhanced secretion of cyclodextrin glucanotransferase (CGTase) by Lactococcus lactis using heterologous signal peptides and optimization of cultivation conditions
    Mahmud H, Ismail A, Abdul Rahim R, Low KO, Md Illias R
    J Biotechnol, 2019 Apr 20;296:22-31.
    PMID: 30878516 DOI: 10.1016/j.jbiotec.2019.02.013
    In previous studies of Lactococcus lactis, the levels of proteins secreted using heterologous signal peptides were observed to be lower than those obtained using the signal peptide from Usp45, the major secreted lactococcal protein. In this study, G1 (the native signal peptide of CGTase) and the signal peptide M5 (mutant of the G1 signal peptide) were introduced into L. lactis to investigate the effect of signal peptides on lactococcal protein secretion to improve secretion efficiency. The effectiveness of these signal peptides were compared to the Usp45 signal peptide. The highest secretion levels were obtained using the G1 signal peptide. Sequence analysis of signal peptide amino acids revealed that a basic N-terminal signal peptide is not absolutely required for efficient protein export in L. lactis. Moreover, the introduction of a helix-breaking residue in the H-region of the M5 signal peptide caused a reduction in the signal peptide hydrophobicity and decreased protein secretion. In addition, the optimization of cultivation conditions for recombinant G1-CGTase production via response surface methodology (RSM) showed that CGTase activity increased approximately 2.92-fold from 5.01 to 16.89 U/ml compared to the unoptimized conditions.
    Matched MeSH terms: Lactococcus lactis
  2. Fulltext The effect of Probiotic mouthrinse on plaque and gingival inflammation
    Noordin, K., Kamin, S.
    Ann Dent, 2007;14(1):19-25.
    MyJurnal
    This study evaluated the effect of a Probiotic mouthrinse containing nisin, a bacteriocin extracted from Lactococcus lactis on dental plaque and gingivitis in young adult population. A group of 32 subjects were randomly assigned into two groups of 16 each. The first group started using the control mouthrinse (placebo) for 2 weeks followed by a washout period of 4 weeks. This group then used the test mouthrinse (Probiotic) for a further duration of 2 weeks. The second group followed a similar protocol as the first except that this group started with the test mouthrinse (Probiotic). Plaque Index (PI) and Gingival Index (GI) were recorded at baseline and after 2 weeks for each group. All subjects were given full mouth prophylaxis after each measurements. The results of this study showed that rinsing with Probiotic mouthrinse resulted in a statistically significant reduction of plaque accumulation and gingivitis compared to rinsing with placebo. The results indicated that Probiotic mouthrinse containing nisin had the potential of inhibiting plaque accumulation and was effective in reducing gingivitis.
    Matched MeSH terms: Lactococcus lactis
  3. Cell surface display system for Lactococcus lactis: a novel development for oral vaccine
    Raha AR, Varma NR, Yusoff K, Ross E, Foo HL
    Appl Microbiol Biotechnol, 2005 Jul;68(1):75-81.
    PMID: 15635459
    The food-grade Lactococcus lactis is a potential vector to be used as a live vehicle for the delivery of heterologous proteins for vaccine and pharmaceutical purposes. We constructed a plasmid vector pSVac that harbors a 255-bp single-repeat sequence of the cell wall-binding protein region of the AcmA protein. The recombinant plasmid was transformed into Escherichia coli and expression of the gene fragment was driven by the T7 promoter of the plasmid. SDS-PAGE showed the presence of the putative AcmA' fragment and this was confirmed by Western blot analysis. The protein was isolated and purified using a His-tag affinity column. When mixed with a culture of L. lactis MG1363, ELISA and immunofluorescence assays showed that the cell wall-binding fragment was anchored onto the outer surface of the bacteria. This indicated that the AcmA' repeat unit retained the active site for binding onto the cell wall surface of the L. lactis cells. Stability assays showed that the fusion proteins (AcmA/A1, AcmA/A3) were stably docked onto the surface for at least 5 days. The AcmA' fragment was also shown to be able to strongly bind onto the cell surface of naturally occurring lactococcal strains and Lactobacillus and, with less strength, the cell surface of Bacillus sphericus. The new system designed for cell surface display of recombinant proteins on L. lactis was evaluated for the expression and display of A1 and A3 regions of the VP1 protein of enterovirus 71 (EV71). The A1 and A3 regions of the VP1 protein of EV71 were cloned upstream to the cell wall-binding domains of AcmA protein and successfully expressed as AcmA/A1 and AcmA/A3. Whole-cell ELISA showed the successful display of VP1 protein epitopes of EV71 on the surface of L. lactis. The success of the anchoring system developed in this study for docking the A1 and A3 epitopes of VP1 onto the surface of L. lactis cells opens up the possibilities of peptide and protein display for not only Lactococcus but also for other gram-positive bacteria. This novel way of displaying epitopes on the cell surface of L. lactis and other related organisms should be very useful in the delivery of vaccines and other useful proteins.
    Matched MeSH terms: Lactococcus lactis/genetics*
  4. Construction of a novel inducible expression vector for Lactococcus lactis M4 and Lactobacillus plantarum Pa21
    Maidin MS, Song AA, Jalilsood T, Sieo CC, Yusoff K, Rahim RA
    Plasmid, 2014 Jul;74:32-8.
    PMID: 24879963 DOI: 10.1016/j.plasmid.2014.05.003
    A vector that drives the expression of the reporter gusA gene in both Lactobacillus plantarum and Lactococcus lactis was constructed in this study. This vector contained a newly characterized heat shock promoter (Phsp), amplified from an Enterococcus faecium plasmid, pAR6. Functionality and characterization of this promoter was initially performed by cloning Phsp into pNZ8008, a commercial lactococcal plasmid used for screening of putative promoters which utilizes gusA as a reporter. It was observed that Phsp was induced under heat, salinity and alkaline stresses or a combination of all three stresses. The newly characterized Phsp promoter was then used to construct a novel Lactobacillus vector, pAR1801 and its ability to express the gusA under stress-induced conditions was reproducible in both Lb. plantarum Pa21 and L. lactis M4 hosts.
    Matched MeSH terms: Lactococcus lactis/genetics*
  5. Fulltext Lactococcus lactis Strain Plasma Intake Suppresses the Incidence of Dengue Fever-like Symptoms in Healthy Malaysians: A Randomized, Double-Blind, Placebo-Controlled Trial
    Khor CS, Tsuji R, Lee HY, Nor'e SS, Sahimin N, Azman AS, et al.
    Nutrients, 2021 Dec 16;13(12).
    PMID: 34960061 DOI: 10.3390/nu13124507
    Dengue fever (DF) is a mosquito-borne disease still with no effective treatment or vaccine available. A randomized, placebo-controlled, double-blinded, parallel-group trial was undertaken to evaluate the efficacy of oral intake of Lactococcus lactis strain plasma (LC-Plasma) on the presentation and severity of DF-like symptoms among healthy volunteers. Study participants (320) were assigned into two groups, and consumed either placebo or LC-Plasma tablets (approximately 100 billion cells/day) for 8 weeks. The clinical symptoms of DF were self-recorded through questionnaires, and exposure to DENV was determined by serum antibody and/or DENV antigen tests. No significant differences between groups were observed for exposure to DENV, or the symptomatic ratio. Results obtained showed that participants from the LC-Plasma group reported a significant reduction in the cumulative incidence days of DF-like symptoms, which include fever (p < 0.001), muscle pain (p < 0.005), joint pain (p < 0.001), and pain behind the eyes (p < 0.001), compared to that of the placebo group. Subgroup analysis revealed a significantly (p < 0.05) reduced severity score in the LC-Plasma group when study sites were separately analyzed. Overall, our findings suggest that LC-Plasma supplementation reduces the cumulative days with DF-like symptoms, and the severity of the symptoms. Daily oral intake of LC-Plasma, hence, is shown to mitigate the DF-like symptoms.
    Matched MeSH terms: Lactococcus lactis/immunology*
  6. Fulltext Oral immunization of a non-recombinant Lactococcus lactis surface displaying influenza hemagglutinin 1 (HA1) induces mucosal immunity in mice
    Jee PF, Tiong V, Shu MH, Khoo JJ, Wong WF, Abdul Rahim R, et al.
    PLoS One, 2017;12(11):e0187718.
    PMID: 29108012 DOI: 10.1371/journal.pone.0187718
    Mucosal immunization of influenza vaccine is potentially an effective approach for the prevention and control of influenza. The objective of the present study was to evaluate the ability of oral immunization with a non-recombinant Lactococcus lactis displaying HA1/L/AcmA recombinant protein, LL-HA1/L/AcmA, to induce mucosal immune responses and to accord protection against influenza virus infection in mice. The LL-HA1/L/AcmA was orally administered into mice and the immune response was evaluated. Mice immunized with LL-HA1/L/AcmA developed detectable specific sIgA in faecal extract, small intestine wash, BAL fluid and nasal fluid. The results obtained demonstrated that oral immunization of mice with LL-HA1/L/AcmA elicited mucosal immunity in both the gastrointestinal tract and the respiratory tract. The protective efficacy of LL-HA1/L/AcmA in immunized mice against a lethal dose challenge with influenza virus was also assessed. Upon challenge, the non-immunized group of mice showed high susceptibility to influenza virus infection. In contrast, 7/8 of mice orally immunized with LL-HA1/L/AcmA survived. In conclusion, oral administration of LL-HA1/L/AcmA in mice induced mucosal immunity and most importantly, provided protection against lethal influenza virus challenge. These results highlight the potential application of L. lactis as a platform for delivery of influenza virus vaccine.
    Matched MeSH terms: Lactococcus lactis/metabolism*
  7. Fulltext Microencapsulation of Lactococcus lactis Gh1 with Gum Arabic and Synsepalum dulcificum via Spray Drying for Potential Inclusion in Functional Yogurt
    Fazilah NF, Hamidon NH, Ariff AB, Khayat ME, Wasoh H, Halim M
    Molecules, 2019 Apr 11;24(7).
    PMID: 30978923 DOI: 10.3390/molecules24071422
    There has been an explosion of probiotic incorporated based product. However, many reports indicated that most of the probiotics have failed to survive in high quantity, which has limited their effectiveness in most functional foods. Thus, to overcome this problem, microencapsulation is considered to be a promising process. In this study, Lactococcus lactis Gh1 was encapsulated via spray-drying with gum Arabic together with Synsepalum dulcificum or commonly known as miracle fruit. It was observed that after spray-drying, high viability (~10⁸ CFU/mL) powders containing L. lactis in combination with S. dulcificum were developed, which was then formulated into yogurt. The tolerance of encapsulated bacterial cells in simulated gastric juice at pH 1.5 was tested in an in-vitro model and the result showed that after 2 h, cell viability remained high at 1.11 × 10⁶ CFU/mL. Incubation of encapsulated cells in the presence of 0.6% (w/v) bile salts showed it was able to survive (~10⁴ CFU/mL) after 2 h. Microencapsulated L. lactis retained a higher viability, at ~10⁷ CFU/mL, when incorporated into yogurt compared to non-microencapsulated cells ~10⁵ CFU/mL. The fortification of microencapsulated and non-microencapsulated L. lactis in yogurts influenced the viable cell counts of yogurt starter cultures, Lactobacillus delbrueckii subs. bulgaricus and Streptococcus thermophilus.
    Matched MeSH terms: Lactococcus lactis/chemistry*
  8. Different effects of two newly-isolated probiotic Lactobacillus plantarum 15HN and Lactococcus lactis subsp. Lactis 44Lac strains from traditional dairy products on cancer cell lines
    Haghshenas B, Abdullah N, Nami Y, Radiah D, Rosli R, Khosroushahi AY
    Anaerobe, 2014 Dec;30:51-9.
    PMID: 25168457 DOI: 10.1016/j.anaerobe.2014.08.009
    Lactobacillus and Lactococcus strains isolated from food products can be introduced as probiotics because of their health-promoting characteristics and non-pathogenic nature. This study aims to perform the isolation, molecular identification, and probiotic characterization of Lactobacillus and Lactococcus strains from traditional Iranian dairy products. Primary probiotic assessments indicated high tolerance to low pH and high bile salt conditions, high anti-pathogenic activities, and susceptibility to high consumption antibiotics, thus proving that both strains possess probiotic potential. Cytotoxicity assessments were used to analyze the effects of the secreted metabolite on different cancer cell lines, including HT29, AGS, MCF-7, and HeLa, as well as a normal human cell line (HUVEC). Results showed acceptable cytotoxic properties for secreted metabolites (40 μg/ml dry weight) of Lactococcus lactis subsp. Lactis 44Lac. Such performance was similar to that of Taxol against all of the treated cancer cell lines; however, the strain exhibited no toxicity on the normal cell line. Cytotoxic assessments through flow cytometry and fluorescent microscopy demonstrated that apoptosis is the main cytotoxic mechanism for secreted metabolites of L. lactis subsp. Lactis 44Lac. By contrast, the effects of protease-treated metabolites on the AGS cell line verified the protein nature of anti-cancer metabolites. However, precise characterizations and in vitro/in vivo investigations on purified proteins should be conducted before these metabolites are introduced as potential anti-cancer therapeutics.
    Matched MeSH terms: Lactococcus lactis/drug effects; Lactococcus lactis/isolation & purification; Lactococcus lactis/metabolism; Lactococcus lactis/physiology*
  9. Fulltext Engineering the lactococcal mevalonate pathway for increased sesquiterpene production
    Song AA, Abdullah JO, Abdullah MP, Shafee N, Othman R, Noor NM, et al.
    FEMS Microbiol Lett, 2014 Jun;355(2):177-84.
    PMID: 24828482 DOI: 10.1111/1574-6968.12469
    Isoprenoids are a large, diverse group of secondary metabolites which has recently raised a renewed research interest due to genetic engineering advances, allowing specific isoprenoids to be produced and characterized in heterologous hosts. Many researches on metabolic engineering of heterologous hosts for increased isoprenoid production are focussed on Escherichia coli and yeasts. E. coli, as most prokaryotes, use the 2-C-methyl-d-erythritol-4-phosphate (MEP) pathway for isoprenoid production. Yeasts on the other hand, use the mevalonate pathway which is commonly found in eukaryotes. However, Lactococcus lactis is an attractive alternative host for heterologous isoprenoid production. Apart from being food-grade, this Gram-positive prokaryote uses the mevalonate pathway for isoprenoid production instead of the MEP pathway. Previous studies have shown that L. lactis is able to produce sesquiterpenes through heterologous expression of plant sesquiterpene synthases. In this work, we analysed the gene expression of the lactococcal mevalonate pathway through RT-qPCR to successfully engineer L. lactis as an efficient host for isoprenoid production. We then overexpressed the mvk gene singly or co-expressed with the mvaA gene as an attempt to increase β-sesquiphellandrene production in L. lactis. It was observed that co-expression of mvk with mvaA doubled the amount of β-sesquiphellandrene produced.
    Matched MeSH terms: Lactococcus lactis/genetics*; Lactococcus lactis/metabolism
  10. Fulltext Live recombinant Lactococcus lactis vaccine expressing aerolysin genes D1 and D4 for protection against Aeromonas hydrophila in tilapia (Oreochromis niloticus)
    Anuradha K, Foo HL, Mariana NS, Loh TC, Yusoff K, Hassan MD, et al.
    J Appl Microbiol, 2010 Nov;109(5):1632-42.
    PMID: 20602654 DOI: 10.1111/j.1365-2672.2010.04789.x
    To evaluate a live recombinant Lactococcus lactis vaccine expressing aerolysin genes D1 (Lac-D1ae) and/or D4 (Lac-D4ae) in protection against Aeromonas hydrophila in tilapia (Oreochromis niloticus).
    Matched MeSH terms: Lactococcus lactis/genetics*; Lactococcus lactis/immunology*
  11. Fulltext Overexpressing 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) in the lactococcal mevalonate pathway for heterologous plant sesquiterpene production
    Song AA, Abdullah JO, Abdullah MP, Shafee N, Othman R, Tan EF, et al.
    PLoS One, 2012;7(12):e52444.
    PMID: 23300671 DOI: 10.1371/journal.pone.0052444
    Isoprenoids are a large and diverse group of metabolites with interesting properties such as flavour, fragrance and therapeutic properties. They are produced via two pathways, the mevalonate pathway or the 2-C-methyl-D-erythritol-4-phosphate (MEP) pathway. While plants are the richest source of isoprenoids, they are not the most efficient producers. Escherichia coli and yeasts have been extensively studied as heterologous hosts for plant isoprenoids production. In the current study, we describe the usage of the food grade Lactococcus lactis as a potential heterologous host for the production of sesquiterpenes from a local herbaceous Malaysian plant, Persicaria minor (synonym Polygonum minus). A sesquiterpene synthase gene from P. minor was successfully cloned and expressed in L. lactis. The expressed protein was identified to be a β-sesquiphellandrene synthase as it was demonstrated to be functional in producing β-sesquiphellandrene at 85.4% of the total sesquiterpenes produced based on in vitro enzymatic assays. The recombinant L. lactis strain developed in this study was also capable of producing β-sesquiphellandrene in vivo without exogenous substrates supplementation. In addition, overexpression of the strain's endogenous 3-hydroxy-3-methylglutaryl coenzyme-A reductase (HMGR), an established rate-limiting enzyme in the eukaryotic mevalonate pathway, increased the production level of β-sesquiphellandrene by 1.25-1.60 fold. The highest amount achieved was 33 nM at 2 h post-induction.
    Matched MeSH terms: Lactococcus lactis/genetics*; Lactococcus lactis/metabolism*
  12. Lactococcus lactis harbouring Ara h 2.02 alleviates allergen-specific Th2-associated responses in sensitized mice
    Chan CJ, Yong YS, Song AAL, Abdul Rahim R, In LLA, Lim RLH
    J Appl Microbiol, 2020 Mar;128(3):862-874.
    PMID: 31758869 DOI: 10.1111/jam.14524
    AIM: To study the prophylactic effect of recombinant Lactococcus lactis (rLl) harbouring Ara h 2.02 peanut allergen, in sensitized and challenged mice.

    METHODS AND RESULTS: Ara h 2.02 cDNA was cloned into pNZ8048 for heterologous expression in L. lactis. The purified recombinant allergen showed IgE binding comparable with native Ara h 2. Balb/c mice were fed with either recombinant (rLl), nonrecombinant L. lactis (Ll) or NaHCO3 (Sham) prior to sensitization and challenged with rAra h 2.02, whereas the baseline group was only fed with Ll. Allergen-specific immunoglobulin and splenocyte cytokines responses were determined for each mouse. Mice fed with either Ll or rLl showed significant alleviation of IgE and IgG1 compared to the Sham group. Despite no significant decrease in Th2 (IL-4, IL-13, IL-6) or increase in Th1 (IFN-γ) cytokines, both groups showed lower IL-10 level, while the IL-4 : IFN-γ ratio was significantly lower for rLl compared to Ll group.

    CONCLUSIONS: Oral administration of rLl harbouring Ara h 2.02 demonstrated alleviation of Th2-associated responses in allergen-challenged mice and a possible added allergen-specific prophylactic effect.

    SIGNIFICANCE AND IMPACT OF THE STUDY: Ara h 2.02 coupled with the intrinsic properties of probiotic L. lactis as a delivery vehicle can be explored for the development of a commercially scalable vaccine.

    Matched MeSH terms: Lactococcus lactis/genetics*; Lactococcus lactis/immunology*
  13. Influence of Culture Conditions and Medium Compositions on the Production of Bacteriocin-Like Inhibitory Substances by Lactococcus lactis Gh1
    Jawan R, Abbasiliasi S, Tan JS, Mustafa S, Halim M, Ariff AB
    Microorganisms, 2020 Sep 23;8(10).
    PMID: 32977375 DOI: 10.3390/microorganisms8101454
    Antibacterial peptides or bacteriocins produced by many strains of lactic acid bacteria have been used as food preservatives for many years without any known adverse effects. Bacteriocin titres can be modified by altering the physiological and nutritional factors of the producing bacterium to improve the production in terms of yield and productivity. The effects of culture conditions (initial pH, inoculum age and inoculum size) and medium compositions (organic and inorganic nitrogen sources; carbon sources) were assessed for the production of bacteriocin-like inhibitory substances (BLIS) by Lactococcus lactis Gh1 in shake flask cultures. An inoculum of the mid-exponential phase culture at 1% (v/v) was the optimal age and size, while initial pH of culture media at alkaline and acidic state did not show a significant impact on BLIS secretion. Organic nitrogen sources were more favourable for BLIS production compared to inorganic sources. Production of BLIS by L. lactis Gh1 in soytone was 1.28-times higher as compared to that of organic nitrogen sources ((NH4)2SO4). The highest cell concentration (XmX = 0.69 ± 0.026 g·L-1) and specific growth rate (μmax = 0.14 h-1) were also observed in cultivation using soytone. By replacing carbon sources with fructose, BLIS production was increased up to 34.94% compared to BHI medium, which gave the biomass cell concentration and specific growth rate of 0.66 ± 0.002 g·L-1 and 0.11 h-1, respectively. It can be concluded that the fermentation factors have pronounced influences on the growth of L. lactis Gh1 and BLIS production. Results from this study could be used for subsequent application in process design and optimisation for improving BLIS production by L. lactis Gh1 at larger scale.
    Matched MeSH terms: Lactococcus lactis
  14. Fulltext Lactococcus Lactis Strain A5 Producing Nisin-like Bacteriocin Active against Gram Positive and Negative Bacteria
    Azhar NS, Md Zin NH, Hamid THTA
    Trop Life Sci Res, 2017 Jul;28(2):107-118.
    PMID: 28890764 MyJurnal DOI: 10.21315/tlsr2017.28.2.8
    In this study, a Lactic acid bacteria (LAB) strain was isolated on MRS medium from gastro-intestinal tissues of Broadhead catfish (Clarias macrocephalus). Out of 50 isolates, 25 isolates were found to be positive on lactose utilisation test and were identified to be gram positive cocci. Using disc diffusion methods, one out of 22 isolates, i.e., a strain A5 demonstrated inhibitions against three indicator organisms; Bacillus cereus, Staphylococcus aureus and Salmonella thyphimurium. Partial 16S rDNA sequencing identified isolate A5 as a member of Lactococcus lactis, with 100% DNA homology. Cell free supernatant fluid from Lactococcus lactis A5 showed inhibitory activities against both gram positive pathogens (Bacillus cereus and Staphylococcus aureus) and gram negative pathogens (Salmonella thyphimurium). Chloroform precipitated bacteriocin retained antagonistic activities in the presence of catalase and lysozyme; and was completely inactivated by Proteinase K treatment. The bacteriocin has a molecular weight of 3.4 kDa, based on SDS-PAGE analysis and the extract was heat stable at 37°C and 65°C, for 15 minutes. The antibacterial activity was suppressed with the addition of EDTA but was significantly increased with the addition of SDS, Triton X-100, Tween 20 and Tween 80. This bacteriocin belongs to class 1 bacteriocin, which was shown to have a nisin-like properties. This strain can be used as potential probiotics in animal or aquaculture feeding; and the bacteriocin it produces will be useful in food preservative.
    Matched MeSH terms: Lactococcus lactis
  15. Insertion of single-chain variable fragment (scFv) peptide linker improves surface display of influenza hemagglutinin (HA1) on non-recombinant Lactococcus lactis
    Jee PF, Chen FS, Shu MH, Wong WF, Abdul Rahim R, AbuBakar S, et al.
    Biotechnol Prog, 2017 Jan;33(1):154-162.
    PMID: 27802566 DOI: 10.1002/btpr.2400
    Heterologous protein displayed on the surface of Lactococcus lactis using the binding domain of N-acetylmuramidase (AcmA) has a potential application in vaccine delivery. In this study, we developed a non-recombinant L. lactis surface displaying the influenza A (H1N1) 2009 hemagglutinin (HA1). Three recombinant proteins, HA1/L/AcmA, HA1/AcmA, and HA1 were overexpressed in Escherichia coli, and purified. In the binding study using flow cytometry, the HA1/L/AcmA, which contained the single-chain variable fragment (scFv) peptide linker showed significantly higher percentage of binding counts and mean fluorescence binding intensity (MFI) (51.7 ± 1.4% and 3,594.0 ± 675.9, respectively) in comparison to the HA1/AcmA without the scFv peptide linker (41.1 ± 1.5% and 1,652.0 ± 34.1, respectively). Higher amount of HA1/L/AcmA (∼2.9 × 10(4) molecules per cell) was displayed on L. lactis when compared to HA1/AcmA (∼1.1 × 10(4) molecules per cell) in the immunoblotting analysis. The HA1/L/AcmA completely agglutinated RBCs at comparable amount of protein to that of HA1/AcmA and HA1. Computational modeling of protein structures suggested that scFv peptide linker in HA1/L/AcmA kept the HA1 and the AcmA domain separated at a much longer distance in comparison to HA1/AcmA. These findings suggest that insertion of the scFv peptide linker between HA1 and AcmA improved binding of recombinant proteins to L. lactis. Hence, insertion of scFv peptide linker can be further investigated as a potential approach for improvement of heterologous proteins displayed on the surface of L. lactis using the AcmA binding domain. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:154-162, 2017.
    Matched MeSH terms: Lactococcus lactis
  16. Fulltext Functional expression of an orchid fragrance gene in Lactococcus lactis
    Song AA, Abdullah JO, Abdullah MP, Shafee N, Rahim RA
    Int J Mol Sci, 2012;13(2):1582-97.
    PMID: 22408409 DOI: 10.3390/ijms13021582
    Vanda Mimi Palmer (VMP), an orchid hybrid of Vanda tesselata and Vanda Tan Chay Yan is a highly scented tropical orchid which blooms all year round. Previous studies revealed that VMP produces a variety of isoprenoid volatiles during daylight. Isoprenoids are well known to contribute significantly to the scent of most fragrant plants. They are a large group of secondary metabolites which may possess valuable characteristics such as flavor, fragrance and toxicity and are produced via two pathways, the mevalonate (MVA) pathway or/and the 2-C-methyl-D-erythritol-4-phosphate (MEP) pathway. In this study, a sesquiterpene synthase gene denoted VMPSTS, previously isolated from a floral cDNA library of VMP was cloned and expressed in Lactococcus lactis to characterize the functionality of the protein. L. lactis, a food grade bacterium which utilizes the mevalonate pathway for isoprenoid production was found to be a suitable host for the characterization of plant terpene synthases. Through recombinant expression of VMPSTS, it was revealed that VMPSTS produced multiple sesquiterpenes and germacrene D dominates its profile.
    Matched MeSH terms: Lactococcus lactis/genetics*
  17. DNA sequence analysis of a small cryptic plasmid from Lactococcus lactis subsp. lactis M14
    Raha AR, Hooi WY, Mariana NS, Radu S, Varma NR, Yusoff K
    Plasmid, 2006 Jul;56(1):53-61.
    PMID: 16675013
    A small plasmid designated pAR141 was isolated from Lactococcus lactis subsp. lactis M14 and its complete 1,594 base pair nucleotide sequence was determined. Analysis of the sequence indicated that this plasmid does not carry any industrially important determinants besides the elements involved in plasmid replication and control. The transcriptional repressor CopG and replication initiation protein RepB appeared as a single operon. A small countertranscribed RNA (ctRNA) coding region was found between the copG and repB genes. The double strand origin (dso) and single strand origin (sso) of rolling circle replicating (RCR) plasmids were also identified in pAR141, suggesting that this plasmid replicates by rolling circle (RC) mode. This observation was supported by S1 nuclease and Southern hybridization analyses.
    Matched MeSH terms: Lactococcus lactis/genetics*
  18. Fulltext Molecular characterization of a recombinant manganese superoxide dismutase from Lactococcus lactis M4
    Tan BH, Chor Leow T, Foo HL, Abdul Rahim R
    Biomed Res Int, 2014;2014:469298.
    PMID: 24592392 DOI: 10.1155/2014/469298
    A superoxide dismutase (SOD) gene of Lactococcus lactis M4 was cloned and expressed in a prokaryotic system. Sequence analysis revealed an open reading frame of 621 bp which codes for 206 amino acid residues. Expression of sodA under T7 promoter exhibited a specific activity of 4967 U/mg when induced with 1 mM of isopropyl-β-D-thiogalactopyranoside. The recombinant SOD was purified to homogeneity by immobilised metal affinity chromatography and Superose 12 gel filtration chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and western blot analyses of the recombinant SOD detected a molecular mass of approximately 27 kDa. However, the SOD was in dimer form as revealed by gel filtration chromatography. The purified recombinant enzyme had a pI of 4.5 and exhibited maximal activity at 25°C and pH 7.2. It was stable up to 45°C. The insensitivity of this lactococcal SOD to cyanide and hydrogen peroxide established that it was a MnSOD. Although it has 98% homology to SOD of L. lactis IL1403, this is the first elucidated structure of lactococcal SOD revealing active sites containing the catalytic manganese coordinated by four ligands (H-27, H-82, D-168, and H-172).
    Matched MeSH terms: Lactococcus lactis/enzymology*
  19. Fulltext K-Ras Peptide Mimotope Induces Antigen Specific Th1 and B-Cell Immune Responses against G12A-Mutated K-Ras Antigen in Balb/c Mice
    Siak PY, Wong KY, Song AA, Rahim RA, In LLA
    Vaccines (Basel), 2021 Feb 26;9(3).
    PMID: 33652552 DOI: 10.3390/vaccines9030195
    KRAS G12A somatic point mutation in adenocarcinomas is categorized clinically as ineligibility criteria for anti-epidermal growth factor receptor (EGFR) monoclonal antibody therapies. In this study, a modified G12A-K-ras epitope (139A) with sequence-specific modifications to improve immunogenicity was developed as a potential vaccine against G12A-mutant KRAS cancers. Additionally, coupling of the 139A epitope with a tetanus toxoid (TTD) universal T-cell epitope to improve antigenicity was also reported. To facilitate convenient oral administration, Lactococcus lactis, which possesses innate immunomodulatory properties, was chosen as a live gastrointestinal delivery vehicle. Recombinant L. lactis strains secreting a G12A mutated K-ras control and 139A with and without TTD fusion were generated for comparative immunogenicity assessment. BALB/c mice were immunized orally, and high survivability of L. lactis passage through the gastrointestinal tract was observed. Elevations in B-cell count with a concomitant titre of antigen-specific IgG and interferon-γ secreting T-cells were observed in the 139A treated mice group. Interestingly, an even higher antigen-specific IgA response and interferon-γ secreting T-cell counts were observed in 139A-TTD mice group upon re-stimulation with the G12A mutated K-ras antigen. Collectively, these results indicated that an antigen-specific immune response was successfully stimulated by 139A-TTD vaccine, and a TTD fusion was successful in further enhancing the immune responses.
    Matched MeSH terms: Lactococcus lactis
  20. Fulltext Influence of miracle fruit (Synsepalum dulcificum) extract and microencapsulated Lactococcus lactis Gh1 on the antioxidant activity and probiotic viability of functional yogurt
    Fazilah, N. F., Zani, N. F. A., Wasoh, H., Ariff, A., Halim, M.
    International Food Research Journal, 2020;27(4):683-693.
    MyJurnal
    Nowadays, functional food market is dominated by dairy-based probiotic products, mainly
    yogurt. The nutritional values of yogurt can be further enhanced by the inclusion of miracle
    fruit (Synsepalum dulcificum) and potential probiotic Lactococcus lactis Gh1. The present
    work investigated the anti-oxidative capacity and survivability of probiotic strains of six
    yogurts fortified with S. dulcificum pulp extract and encapsulated L. lactis Gh1 (in
    alginate-starch coating agent via extrusion technique). The flavonoid contents (TFC) were not
    significantly different between yogurts, whereas the phenolic contents (TPC) showed an
    increasing trend throughout the storage. Among the yogurts, the one supplemented with both
    S. dulcificum and encapsulated L. lactis Gh1 showed the highest TFC (1.18 µg QE/mL) and
    TPC (15.382 μg GAE/mL). The antioxidant assay (DPPH) showed a gradual increase on the
    first 7 d, but decreased afterward. In comparison, yogurts fortified with S. dulcificum demonstrated higher antioxidant activity (± 80% DPPH inhibition) than the plain yogurts (± 50%
    DPPH inhibition). The viability of starter cultures (Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus) drastically increased during the first week (log 8 ~ 10
    CFU/mL) especially for yogurts containing free cell L. lactis, but subsequently decreased ( log
    6 ~ 8 CFU/mL). The viability of L. lactis Gh1 in yogurts maintained at high count (log 9.43
    and 9.04 CFU/mL) throughout 21 d when it was being encapsulated. In general, the fortification of S. dulcificum extract with microencapsulated L. lactis Gh1 had greatly enhanced the
    quality and potential benefits of the functional yogurts.
    Matched MeSH terms: Lactococcus lactis
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