Displaying publications 1 - 20 of 81 in total

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  1. Fulltext pH dominates variation in tropical soil archaeal diversity and community structure
    Tripathi BM, Kim M, Lai-Hoe A, Shukor NA, Rahim RA, Go R, et al.
    FEMS Microbiol Ecol, 2013 Nov;86(2):303-11.
    PMID: 23773164 DOI: 10.1111/1574-6941.12163
    Little is known of the factors influencing soil archaeal community diversity and composition in the tropics. We sampled soils across a range of forest and nonforest environments in the equatorial tropics of Malaysia, covering a wide range of pH values. DNA was PCR-amplified for the V1-V3 region of the 16S rRNA gene, and 454-pyrosequenced. Soil pH was the best predictor of diversity and community composition of Archaea, being a stronger predictor than land use. Archaeal OTU richness was highest in the most acidic soils. Overall archaeal abundance in tropical soils (determined by qPCR) also decreased at higher pH. This contrasts with the opposite trend previously found in temperate soils. Thaumarcheota group 1.1b was more abundant in alkaline soils, whereas group 1.1c was only detected in acidic soils. These results parallel those found in previous studies in cooler climates, emphasizing niche conservatism among broad archaeal groups. Among the most abundant operational taxonomic units (OTUs), there was clear evidence of niche partitioning by pH. No individual OTU occurred across the entire range of pH values. Overall, the results of this study show that pH plays a major role in structuring tropical soil archaeal communities.
  2. Fulltext Ultrasensitive and Highly Selective Graphene-Based Field-Effect Transistor Biosensor for Anti-Diuretic Hormone Detection
    Selvarajan RS, Rahim RA, Majlis BY, Gopinath SCB, Hamzah AA
    Sensors (Basel), 2020 May 06;20(9).
    PMID: 32384631 DOI: 10.3390/s20092642
    Nephrogenic diabetes insipidus (NDI), which can be congenital or acquired, results from the failure of the kidney to respond to the anti-diuretic hormone (ADH). This will lead to excessive water loss from the body in the form of urine. The kidney, therefore, has a crucial role in maintaining water balance and it is vital to restore this function in an artificial kidney. Herein, an ultrasensitive and highly selective aptameric graphene-based field-effect transistor (GFET) sensor for ADH detection was developed by directly immobilizing ADH-specific aptamer on a surface-modified suspended graphene channel. This direct immobilization of aptamer on the graphene surface is an attempt to mimic the functionality of collecting tube V 2 receptors in the ADH biosensor. This aptamer was then used as a probe to capture ADH peptide at the sensing area which leads to changes in the concentration of charge carriers in the graphene channel. The biosensor shows a significant increment in the relative change of current ratio from 5.76 to 22.60 with the increase of ADH concentration ranging from 10 ag/mL to 1 pg/mL. The ADH biosensor thus exhibits a sensitivity of 50.00 µA· ( g / mL ) - 1 with a limit of detection as low as 3.55 ag/mL. In specificity analysis, the ADH biosensor demonstrated a higher current value which is 338.64 µA for ADH-spiked in phosphate-buffered saline (PBS) and 557.89 µA for ADH-spiked in human serum in comparison with other biomolecules tested. This experimental evidence shows that the ADH biosensor is ultrasensitive and highly selective towards ADH in PBS buffer and ADH-spiked in human serum.
  3. Tropical soil bacterial communities in Malaysia: pH dominates in the equatorial tropics too
    Tripathi BM, Kim M, Singh D, Lee-Cruz L, Lai-Hoe A, Ainuddin AN, et al.
    Microb Ecol, 2012 Aug;64(2):474-84.
    PMID: 22395784 DOI: 10.1007/s00248-012-0028-8
    The dominant factors controlling soil bacterial community variation within the tropics are poorly known. We sampled soils across a range of land use types--primary (unlogged) and logged forests and crop and pasture lands in Malaysia. PCR-amplified soil DNA for the bacterial 16S rRNA gene targeting the V1-V3 region was pyrosequenced using the 454 Roche machine. We found that land use in itself has a weak but significant effect on the bacterial community composition. However, bacterial community composition and diversity was strongly correlated with soil properties, especially soil pH, total carbon, and C/N ratio. Soil pH was the best predictor of bacterial community composition and diversity across the various land use types, with the highest diversity close to neutral pH values. In addition, variation in phylogenetic structure of dominant lineages (Alphaproteobacteria, Beta/Gammaproteobacteria, Acidobacteria, and Actinobacteria) is also significantly correlated with soil pH. Together, these results confirm the importance of soil pH in structuring soil bacterial communities in Southeast Asia. Our results also suggest that unlike the general diversity pattern found for larger organisms, primary tropical forest is no richer in operational taxonomic units of soil bacteria than logged forest, and agricultural land (crop and pasture) is actually richer than primary forest, partly due to selection of more fertile soils that have higher pH for agriculture and the effects of soil liming raising pH.
  4. Fulltext The Discovery of New Antilisterial Proteins From Paenibacillus polymyxa Kp10 via Genome Mining and Mass Spectrometry
    Mokhtar NFK, Hashim AM, Hanish I, Zulkarnain A, Raja Nhari RMH, Abdul Sani AA, et al.
    Front Microbiol, 2020;11:960.
    PMID: 32714281 DOI: 10.3389/fmicb.2020.00960
    The inhibitory properties of novel antimicrobial proteins against food-borne pathogens such as Listeria monocytogenes offer extensive benefits to the food and medical industries. In this study, we have identified antimicrobial proteins from a milk curd-derived bacterial isolate that exhibits antilisterial activity using genome mining and mass spectrometry analysis. The analysis of the draft genome sequence identified the isolate as Paenibacillus polymyxa Kp10, and predicted the presence of antimicrobial paenibacillin, paenilan, paeninodin, sactipeptides, thiazole-oxazole modified microcin, and histone-like DNA binding protein HU encoded in its genome. Interestingly, nanoLC-MS/MS analysis identified two histone-like DNA binding proteins HU as predicted in silico earlier, exhibiting antilisterial activity. Additionally, translation initiation factor IF-1 and 50S ribosomal protein L29 were also discovered by the mass spectrometry in the active fractions. The antilisterial activity of the four proteins was verified through heterologous protein expression and antimicrobial activity assay in vitro. This study has identified structural regulatory proteins from Paenibacillus possessing antilisterial activity with potential future application in the food and medical industries.
  5. TRANSCRIPTOMIC ANALYSIS OF GRACILARIA CHANGII (RHODOPHYTA) IN RESPONSE TO HYPER- AND HYPOOSMOTIC STRESSES(1)
    Teo SS, Ho CL, Teoh S, Rahim RA, Phang SM
    J Phycol, 2009 Oct;45(5):1093-9.
    PMID: 27032354 DOI: 10.1111/j.1529-8817.2009.00724.x
    Osmotic stress is one of the most significant natural abiotic stresses that occur in the intertidal zones. Seaweeds may physiologically acclimate to changing osmolarity by altering their transcriptome. Here, we investigated the transcriptomic changes of Gracilaria changii (B. M. Xia et I. A. Abbott) I. A. Abbott, J. Zhang et B. M. Xia in response to hyper- and hypoosmotic stresses using a cDNA microarray approach. Microarray analysis revealed that 199 and 200 genes from ∼3,300 genes examined were up- and down-regulated by >2-fold in seaweed samples treated at 50 parts per thousand (ppt) artificial seawater (ASW) compared with those at 30 ppt ASW, respectively. The number of genes that were up- and down-regulated by >2-fold in seaweed samples treated at 10 ppt ASW compared with those at 30 ppt ASW were 154 and 187, respectively. A majority of these genes were only differentially expressed under hyper- or hypoosmotic conditions, whereas 67 transcripts were affected by both stresses. The findings of this study have shed light on the expression profiles of many transcripts during the acclimation of G. changii to hyperosmotic and hypoosmotic conditions. This information may assist in the prioritization of genes to be examined in future studies.
  6. Fulltext Surface display of respiratory syncytial virus glycoproteins in Lactococcus lactis NZ9000
    Lim SH, Jahanshiri F, Rahim RA, Sekawi Z, Yusoff K
    Lett Appl Microbiol, 2010 Dec;51(6):658-64.
    PMID: 20973806 DOI: 10.1111/j.1472-765X.2010.02950.x
    A system for displaying heterologous respiratory syncytial virus (RSV) glycoproteins on the surface of Lactococcus lactis NZ9000 was developed.
  7. Successful transfer of plasmid DNA into in vitro cells transfected with an inorganic plasmid-Mg/Al-LDH nanobiocomposite material as a vector for gene expression
    Masarudin MJ, Yusoff K, Rahim RA, Hussein MZ
    Nanotechnology, 2009 Jan 28;20(4):045602.
    PMID: 19417322 DOI: 10.1088/0957-4484/20/4/045602
    The delivery of a full plasmid, encoding the green fluorescent protein gene into African monkey kidney (Vero3) cells, was successfully achieved using nanobiocomposites based on layered double hydroxides. This demonstrated the potential of using the system as an alternative DNA delivery vector. Intercalation of the circular plasmid DNA, pEGFP-N2, into Mg/Al-NO(3)(-) layered double hydroxides (LDH) was accomplished through anion exchange routes to form the nanobiocomposite material. The host was previously synthesized at the Mg(2+) to Al(3+) molar ratio R(i) = 2 and subsequently intercalated with plasmid DNA. Size expansion of the interlamellae host from 8.8 A in LDH to 42 A was observed in the resulting nanobiocomposite, indicating stable hybridization of the plasmid DNA. The powder x-ray diffraction (PXRD) results, supplemented with Fourier-transform infrared (FTIR) spectroscopy, compositional and electrophoresis studies confirmed the encapsulation episode of the biomaterial. In order to elucidate the use of this resulting nanobiocomposite as a delivery vector, an MTT assay was performed to determine any cytotoxic effects of the host towards cells. The intercalated pEGFP-N2 anion was later successfully recovered through acidification with HNO(3) after treatment with DNA-degrading enzymes, thus also showing the ability of the LDH host to protect the intercalated biomaterial from degradation. Cell transfection studies on Vero3 cells were then performed, where cells transfected with the nanobiocomposite exhibited fluorescence as early as 12 h post-treatment compared to naked delivery of the plasmid itself.
  8. Fulltext Strategies in fed-batch cultivation on the production performance of Lactobacillus salivarius I 24 viable cells
    Ming LC, Halim M, Rahim RA, Wan HY, Ariff AB
    Food Sci Biotechnol, 2016;25(5):1393-1398.
    PMID: 30263421 DOI: 10.1007/s10068-016-0217-1
    The potential use of fed-batch cultivation (FBC) for improvement of the production of Lactobacillus salivarius I 24 biomass for subsequent use as probiotics was studied using a 2-L stirredtank bioreactor. Three different constant feeding rates (0.1, 0.05, and 0.033 L/h) were applied in FBCs and their effect on carbon metabolism was evaluated. The carbon flux for cell built-up with reduction in lactic acid synthesis was observed in the fed-batch as compared to the batch cultivation mode. The viable cell number obtained in the constant FBC (CFBC) operated at a feeding rate of 0.05 L/h was 8 times higher (10.7×1010 CFU/mL) than that recorded in the batch cultivation. This gave the viable cell yield based on glucose consumed for CFBC of 26 times higher (11.3×1012 CFU/gGlucose) than the batch cultivation. This study demonstrated CFBC, which is simple with minimal use of process control equipment, has an industrial potential for improvement of probiotic production.
  9. Fulltext Serum Anti-Müllerian Hormone in Polycystic Ovary Syndrome and its Relationship with Insulin Resistance, Lipid Profile and Adiponectin
    Jun TJ, Jelani AM, Omar J, Rahim RA, Yaacob NM
    Indian J Endocrinol Metab, 2020 04 30;24(2):191-195.
    PMID: 32699789 DOI: 10.4103/ijem.IJEM_305_19
    Objectives: This study was done to estimate serum anti-Müllerian hormone (AMH) level in polycystic ovary syndrome (PCOS) patients and to correlate serum AMH level with insulin resistance, lipid profile, and adiponectin levels.

    Materials and Methods: A cross-sectional study was conducted at Hospital Universiti Sains Malaysia (Hospital USM), Health Campus, Kubang Kerian, Kelantan, Malaysia. Thirty newly diagnosed patients with PCOS attending gynecology clinic between July 2016 and April 2017 were recruited. Fasting venous blood samples were collected from the subjects. Serum AMH, insulin, adiponectin, triglycerides, high-density lipoprotein cholesterol (HDL-C), and plasma glucose levels were measured, and insulin resistance was calculated based on homeostasis model of assessment-insulin resistance (HOMA-IR). The serum AMH level was estimated, and the correlation of serum AMH level with the metabolic parameters was analyzed.

    Results: The median of serum AMH levels in women with PCOS was 6.8 ng/mL (interquartile range: 7.38 ng/mL). There was a significant negative correlation between serum AMH and HOMA-IR or triglyceride levels (r = -0.49, P = 0.006 and r = -0.55, P = 0.002, respectively). A significant positive correlation was observed between serum AMH and serum HDL-C or serum adiponectin levels (r = 0.56, P = 0.001 and r = 0.44, P = 0.014, respectively) in all study subjects.

    Conclusion: The serum AMH level is associated with HOMA-IR, triglycerides, HDL-C, and adiponectin levels, and hence it may be used as a potential cardiometabolic risk marker in women with PCOS.

  10. Sequence analysis and characterization of vacuolar-type H+ -ATPase proteolipid transcript from Acanthus ebracteatus Vah1
    Ho CL, Nguyen PD, Harikrishna JA, Rahim RA
    DNA Seq., 2008 Feb;19(1):73-7.
    PMID: 17852357
    The vacuolar-type H+ -ATPase (V-ATPase) is a multimeric enzyme with diverse functions in plants such as nutrient transport, flowering, stress tolerance, guard cell movement and development. A partial sequence of V-ATPase proteolipid was identified among the expressed sequence tags (ESTs) generated from Acanthus ebracteatus, and selected for full-length sequencing. The 876-nucleotide cDNA consists of an open reading frame of 165 amino acids. The deduced amino acid sequence displays high similarity (81%) with its homologs from Arabidopsis thaliana, Avecinnia marina and Gossypium hirsutum with the four transmembrane domains characteristics of the 16 kDa proteolipid subunit c of V-ATPase well conserved in this protein. Southern analysis revealed the existence of several members of proteolipid subunit c of V-ATPase in A. ebracteatus. The mRNA of this gene was detected in leaf, floral, stem and root tissues, however, the expression level was lower in stem and root tissues.
  11. Fulltext Psychoactive plant abuse: the identification of mitragynine in ketum and in ketum preparations
    Chan KB, Pakiam C, Rahim RA
    Bull Narc, 2005;57(1-2):249-56.
    PMID: 21338025
    Recently, the abuse of ketum, an indigenous psychoactive plant, has received a lot of attention in Malaysia. To help national law enforcement agencies control its abuse, the laboratory of the Forensic Division has developed a procedure for its positive identification. Botanical identification may not be practical or conclusive, owing to the wide range of ketum materials available on the market, including dry macerated leaves, powdered leaves and drinks. In order to confirm that a substance is, in fact, ketum or that a preparation is derived from ketum, gas chromatography-mass spectrometry is used to definitively identify the presence of the psychoactive principle mnitragynine.
  12. Proteome analysis of Escherichia coli periplasmic proteins in response to over-expression of recombinant human interferon α2b
    Heidary S, Rahim RA, Eissazadeh S, Moeini H, Chor AL, Abdullah MP
    Biotechnol Lett, 2014 Jul;36(7):1479-84.
    PMID: 24652546 DOI: 10.1007/s10529-014-1504-7
    The periplasmic proteome of recombinant E. coli cells expressing human interferon-α2b (INF-α2b) was analysed by 2D-gel electrophoresis to find the most altered proteins. Of some unique up- and down-regulated proteins in the proteome, ten were identified by MS. The majority of the proteins belonged to the ABC transporter protein family. Other affected proteins were ones involved in the regulation of transcription such as DNA-binding response regulator, stress-related proteins and ecotin. Thus, the production of INF-α2b acts as a stress on the cells and results in the induction of various transporters and stress related proteins.
  13. Profiling the transcriptome of Gracilaria changii (Rhodophyta) in response to light deprivation
    Ho CL, Teoh S, Teo SS, Rahim RA, Phang SM
    Mar Biotechnol (NY), 2009 Jul-Aug;11(4):513-9.
    PMID: 19043658 DOI: 10.1007/s10126-008-9166-x
    Light regulates photosynthesis, growth and reproduction, yield and properties of phycocolloids, and starch contents in seaweeds. Despite its importance as an environmental cue that regulates many developmental, physiological, and biochemical processes, the network of genes involved during light deprivation are obscure. In this study, we profiled the transcriptome of Gracilaria changii at two different irradiance levels using a cDNA microarray containing more than 3,000 cDNA probes. Microarray analysis revealed that 93 and 105 genes were up- and down-regulated more than 3-fold under light deprivation, respectively. However, only 50% of the transcripts have significant matches to the nonredundant peptide sequences in the database. The transcripts that accumulated under light deprivation include vanadium chloroperoxidase, thioredoxin, ferredoxin component, and reduced nicotinamide adenine dinucleotide dehydrogenase. Among the genes that were down-regulated under light deprivation were genes encoding light harvesting protein, light harvesting complex I, phycobilisome 7.8 kDa linker polypeptide, low molecular weight early light-inducible protein, and vanadium bromoperoxidase. Our findings also provided important clues to the functions of many unknown sequences that could not be annotated using sequence comparison.
  14. Primary recovery of a bacteriocin-like inhibitory substance derived from Pediococcus acidilactici Kp10 by an aqueous two-phase system
    Abbasiliasi S, Tan JS, Ibrahim TA, Kadkhodaei S, Ng HS, Vakhshiteh F, et al.
    Food Chem, 2014 May 15;151:93-100.
    PMID: 24423507 DOI: 10.1016/j.foodchem.2013.11.019
    A polymer-salt aqueous two-phase system (ATPS) consisting of polyethylene-glycol (PEG) with sodium citrate was developed for direct recovery of a bacteriocin-like inhibitory substance (BLIS) from a culture of Pediococcus acidilactici Kp10. The influences of phase composition, tie-line length (TLL), volume ratio (VR), crude sample loading, pH and sodium chloride (NaCl) on the partition behaviour of BLIS was investigated. Under optimum conditions of ATPS, the purification of BLIS was achieved at 26.5% PEG (8000)/11% sodium citrate with a TLL of 46.38% (w/w), VR of 1.8, and 1.8% crude load at pH 7 without the presence of NaCl. BLIS from P. acidilactici Kp10 was successfully purified by the ATPS up to 8.43-fold with a yield of 81.18%. Given that the operation of ATPS is simple, environmentally friendly and cost-effective, as it requires only salts and PEG, it may have potential for industrial applications in the recovery of BLIS from fermentation broth.
  15. Fulltext Prevalence of Staphylococcus aureus carriage by young Malaysian footballers during indoor training
    William JL, Radu S, Aziz SA, Rahim RA, Cheah YK, Liwan A, et al.
    Br J Sports Med, 2004 Feb;38(1):12-4.
    PMID: 14751938
    BACKGROUND: Research has shown that athletes are carriers of Staphylococcus aureus during physical activity.
    OBJECTIVE: To estimate the mean total plate count of S aureus carried by footballers before and after training at an indoor venue.
    METHODS: Forty Malay and 20 Indian students volunteered to participate. There was also a control group consisting of 40 Malay and 20 Indian students who were not active. The experimental group were active footballers who had played at school or club level. The subjects were healthy and free of skin infection. The experiment was divided into three sessions, with 20 subjects present at each. At each session, the subjects trained for one hour. Swabs were taken from the skin, nose, and ear before and after training. For the control group, swabs were taken only once from the skin, nose, and ear. The swabs were subjected to biochemical tests and then streaked and cultured aerobically in Baird Parker agar plates for 24 hours at 37 degrees C. Black colonies with a clear zone were presumed to be S aureus, and the mean total plate count of the colonies was estimated. Gram staining, catalase, coagulase slide, coagulase tube, acetoin production, o-nitrophenyl beta-D-galactopyranoside (ONPG), and mannitol fermentation tests were used to confirm the colonies as S aureus. A haemolysin test was conducted with human blood to confirm haemolytic activity.
    RESULTS: All subjects in the experimental group were carrying S aureus both before and after training. The estimated mean total counts of colonies from the skin, ear, and nose for the Malays before training were 33, 71, and 312 respectively. Counts after training were 21, 44, and 452 respectively. The results for the Indians were 72, 80, and 309 respectively before training and 55, 200, and 466 respectively after training. The positive results for Gram staining, catalase, coagulase slide, coagulase tube, acetoin production, ONPG, and mannitol fermentation tests were 100%, 96%, 95%, 95%, 93%, 93%, and 90% respectively. All subjects in the control group were also carrying S aureus.
    CONCLUSIONS: All of the players were carriers of S aureus during training. The decrease in total count from the skin for both races may be due to lysozyme activity lysing the bacterial cells. Contamination of the environment with these bacteria may have increased the estimated total plate count in the nose. The experimental group face a higher risk of infection because of lower immunity during training and higher rate of injuries compared with the control group.
  16. Prevalence of Listeria spp and Listeria monocytogenes in meat and fermented fish in Malaysia
    Hassan Z, Purwati E, Radu S, Rahim RA, Rusul G
    Southeast Asian J. Trop. Med. Public Health, 2001 Jun;32(2):402-7.
    PMID: 11556596
    Fermented fish and meat samples were purchased from supermarket and wet market for microbiological analysis of Listeria species and Listeria monocytogenes contamination. Listeria species were isolated from 17 (73.9%) of 23 samples of imported frozen beef, 10 (43.5%) of the 23 samples of local beef and 14 (56%) of the 25 samples of fermented fish from wet market. Listeria monocytogenes occurred in 15 (75%) of the frozen beef samples, 6 (30.4%) of the 23 samples of local meat and 3 (12%) of the 25 samples from fermented fish. Listeria species was not isolated from any of the 23 samples of imported frozen beef from supermarket and from the 5 samples of buffalo meat examined. This highlights the possibility of Listeria spp or L. monocytogenes to persist in meat and fermented fish in wet market and raises the problem of illness due to the handling and consumption of Listeria-contaminated meat or fermented fish are likely as evidence by the high contamination rates of samples sold at the wet market.
  17. Fulltext Overexpression and optimization of glutamate decarboxylase in Lactobacillus plantarum Taj-Apis362 for high gamma-aminobutyric acid production
    Tajabadi N, Baradaran A, Ebrahimpour A, Rahim RA, Bakar FA, Manap MY, et al.
    Microb Biotechnol, 2015 Jul;8(4):623-32.
    PMID: 25757029 DOI: 10.1111/1751-7915.12254
    Gamma-aminobutyric acid (GABA) is an important bioactive compound biosynthesized by microorganisms through decarboxylation of glutamate by glutamate decarboxylase (GAD). In this study, a full-length GAD gene was obtained by cloning the template deoxyribonucleic acid to pTZ57R/T vector. The open reading frame of the GAD gene showed the cloned gene was composed of 1410 nucleotides and encoded a 469 amino acids protein. To improve the GABA-production, the GAD gene was cloned into pMG36e-LbGAD, and then expressed in Lactobacillus plantarum Taj-Apis362 cells. The overexpression was confirmed by SDS-PAGE and GAD activity, showing a 53 KDa protein with the enzyme activity increased by sevenfold compared with the original GAD activity. The optimal fermentation conditions for GABA production established using response surface methodology were at glutamic acid concentration of 497.973 mM, temperature 36°C, pH 5.31 and time 60 h. Under the conditions, maximum GABA concentration obtained (11.09 mM) was comparable with the predicted value by the model at 11.23 mM. To our knowledge, this is the first report of successful cloning (clone-back) and overexpression of the LbGAD gene from L. plantarum to L. plantarum cells. The recombinant Lactobacillus could be used as a starter culture for direct incorporation into a food system during fermentation for production of GABA-rich products.
  18. Oral vaccine of Lactococcus lactis harbouring pandemic H1N1 2009 haemagglutinin1 and nisP anchor fusion protein elevates anti-HA1 sIgA levels in mice
    Joan SS, Pui-Fong J, Song AA, Chang LY, Yusoff K, AbuBakar S, et al.
    Biotechnol Lett, 2016 May;38(5):793-9.
    PMID: 26758876 DOI: 10.1007/s10529-016-2034-2
    An oral lactococcal-based vaccine which haboured the haemagglutinin1 (HA1) antigen fused to nisP anchor protein for the purpose of surface displaying the HA1 antigen was developed against H1N1 virus.
  19. Oral vaccination with Lactococcus lactis expressing the Vibrio cholerae Wzm protein to enhance mucosal and systemic immunity
    Zamri HF, Shamsudin MN, Rahim RA, Neela V
    Vaccine, 2012 May 2;30(21):3231-8.
    PMID: 22426330 DOI: 10.1016/j.vaccine.2012.02.012
    A gene associated with lipopolysaccharide (LPS) transport was cloned from a local clinical Vibrio cholerae O1 strain of the Ogawa serotype by using the Lactococcus lactis nisin-controlled expression (NICE) system. The V. cholerae wzm gene, which codes for an integral membrane transporter protein, was expressed and targeted to the cytoplasmic membrane, and was crudely isolated through simple centrifugation and SDS solubilization. To examine seroreactivity of this construct, rabbits were orally fed with 10(9) cfu/ml of live, recombinant L. lactis carrying the wzm gene, induced with nisin prior to administration. Recombinant plasmids were retrieved from L. lactis cultured directly from stool samples of inoculated rabbits. Reverse-transcriptase PCR of wzm using the retrieved plasmids confirmed transcription of this gene, indicating viability and stability of the recombinants in vivo. The L. lactis-Wzm construct elicited substantial levels of IgG and sIgA, and challenge with virulent V. cholerae O1 evoked severe diarrhoea in the naive, non-immunised control group, but not in those fed with either recombinant or non-recombinant L. lactis. Oral administration with recombinant L. lactis expressing the V. cholerae wzm gene increases both systemic and mucosal immunity, whereas L. lactis itself appears capable of protecting against the diarrhoeal symptoms caused by V. cholerae. Wzm is a conserved membrane protein associated with the LPS endotoxin, and together with the food-grade L. lactis, represent an attractive target for the development of a safer, live anti-infective therapy against V. cholerae.
  20. Fulltext Optimization of γ-aminobutyric acid production by Lactobacillus plantarum Taj-Apis362 from honeybees
    Tajabadi N, Ebrahimpour A, Baradaran A, Rahim RA, Mahyudin NA, Manap MY, et al.
    Molecules, 2015 Apr 15;20(4):6654-69.
    PMID: 25884548 DOI: 10.3390/molecules20046654
    Dominant strains of lactic acid bacteria (LAB) isolated from honey bees were evaluated for their γ-aminobutyric acid (GABA)-producing ability. Out of 24 strains, strain Taj-Apis362 showed the highest GABA-producing ability (1.76 mM) in MRS broth containing 50 mM initial glutamic acid cultured for 60 h. Effects of fermentation parameters, including initial glutamic acid level, culture temperature, initial pH and incubation time on GABA production were investigated via a single parameter optimization strategy. The optimal fermentation condition for GABA production was modeled using response surface methodology (RSM). The results showed that the culture temperature was the most significant factor for GABA production. The optimum conditions for maximum GABA production by Lactobacillus plantarum Taj-Apis362 were an initial glutamic acid concentration of 497.97 mM, culture temperature of 36 °C, initial pH of 5.31 and incubation time of 60 h, which produced 7.15 mM of GABA. The value is comparable with the predicted value of 7.21 mM.
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