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Characterization of Vibrio parahaemolyticus isolated from coastal water in Eastern Province of Saudi Arabia

Malaysian Journal of Microbiology.2018;14(1):1-9.

Aims: Vibrio parahaemolyticus is a marine and estuarine bacterium that has been documented as the causative agent of food-borne outbreak worldwide. The aim of this study was to confirm the identification of presumptive V. parahaemolyticus isolates to the species level by using PCR targeted to the outer membrane protein regulation operon gene (toxR) and to investigate antibiotic resistance, plasmid profile, and the main core virulence genes of thermostable direct hemolysin (tdh) and tdh-related hemolysin (trh). Methodology and results: A total of 56 presumptive isolates of V. parahaemolyticus were isolated from seawater collected during year a 2010 sampling pilot study performed along the Arabian Gulf coast of the Eastern Province of Saudi Arabia. The purpose of this study was to confirm the identification of presumptive V. parahaemolyticus isolates to the species level by using PCR targeted to the toxR gene and to investigate antibiotic resistance, plasmid profile, and the main core virulence genes of tdh and trh. The toxR-specific PCR assay revealed that a total of 30 out of 56 isolates tested positive for V. parahaemolyticus. None of the 30 strains of the toxR gene were tested positive for tdh and trh genes. All (100%) of isolates were highly resistant to amikacin, cefuroxime, ampicillin, ticarcillin, cefaclor (80%), and tetracycline (70%). The multiple antibiotic resistance (MAR) index was measured for all 16 antimicrobial agents, and the high ranged from 0.25 to 0.56. Among the isolated V. parahaemolyticus, 22 out of 30 strains contained plasmid DNA bands ranging in size from 1.5 to 55 kb and no correlation was observed between the plasmid profiles and antibiotic resistance patterns. Conclusion, significance and impact of study The results obtained in this study indicate that V. parahaemolyticus is present in the coastal environment of the Eastern Province of Saudi Arabia.

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Biodegradation of natural rubber latex film added with Metroxylan Sagu pith form by Bacillus cereus ATCC 14579

Nuraiffa Syazwi Adzami ; Azura A. Rashid ; Husnul Azan Tajarudin

Malaysian Journal of Microbiology.2018;14(2):102-107.

Aims: This study is focused on the potential of Bacillus cereus ATCC 14579 to degrade natural rubber (NR) latex film and NR latex film added with Metroxylan sagu pith waste (NR/TSPW latex film). Methodology and results: Bacillus cereus is proved capable to utilise rubber as main source of carbon and energy. The biodegradation studies were analyzed by growth profile, weight loss, protein content and tensile strength test. Fourier Transform Infrared Spectroscopy (FTIR) test was applied to confirm the biodegradation process. In shake cultures, OD of culture increased by 19.2% from the initial inoculum after 14th cultivation days with NR/TSPW latex film. An increase in protein content up to 0.037 mg/g with 12.377% weight loss of film was obtained after biodegradation. Tensile test result shows tensile strength and elongation break are decreased by 10.203%. Conclusion, significance and impact of study The demand of rubber products is increasing time to time. Due to the high consumable and disposable of rubber latex products, hence remain inert to degradation and leading to their accumulation in the environment. An attempt to combine Natural Rubber (NR) latex system with other degrading materials have been made to facilitate biodegradation process. Thus, Bacillus cereus ATCC 14579 has potency to provide a biotechnological solution to the waste rubber disposal problem.

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Wastewater treatment by microalgae-bacteria co-culture system

Amirah Samsudin ; Azlin Suhaida Azmi ; Mohd Nazri Mohd Nawi ; Amanatuzzakiah Abdul Halim

Malaysian Journal of Microbiology.2018;14(2):131-136.

Aims: Microalgae is one of the bioremediation agents in wastewater treatment due to its ability to degrade nutrients and organic compounds. Several studies reported that co-cultivation of microalgae and bacteria, i.e. Microalgae Growth Promoting Bacteria (MGPB) could improve the nutrients removal process. This MGPB helps to degrade complex nutrient compounds into smaller components before being taken up by microalgae. The objective of this study is to investigate the effectiveness of co-cultured (microalgae and bacteria) system compared to axenic microalgae system in the removal of major nutrients (ammonium and phosphorus) and chemical oxygen demand (COD) in synthetic wastewater. Methodology and results: In this study, two different strains of microalgae (Chlorella vulgaris and Scenedesmus quadricauda) were each co-cultured with a MGPB (Azospirillum brasilense) and their effectiveness in the removal of major nutrients and COD were compared. The results show that, the nutrients and COD removal were higher in co-cultured system compared to the axenic microalgae under similar cultivation conditions for both microalgae strains. Higher percentage removal was obtained from co-cultured C. vulgaris compared to that from co-cultured S. quadricauda which were 86% and 48%, 44% and 31%, 62% and 35% for ammonium, phosphorus and COD removal respectively. Conclusion, significance and impact of study The findings of this study demonstrate the potential of the co-culture of C. vulgaris and A. brasilense to be applied in wastewater treatment, specifically replacing the aerobic digestion process in secondary stage of conventional wastewater treatment. This study provides an important insight into developing an efficient and environmental friendly method to treat wastewater by incorporating the green technology in the treatment system.

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Enhancement of cyanobacterial control by fungi degraded palm oil trunk

Tengku Nadiah T. Yusoff ; Mohd Rafatullah ; Norli Ismail ; Zarina Zainuddin ; Japareng Lalung

Malaysian Journal of Microbiology.2018;14(2):172-179.

Aims: Cyanbacterial bloom can cause unpleasant smell and taste. It can also produce toxins that can be harmful to animals or human. The capability of plant materials to control cyanobacterial bloom has been reported by many researchers. Among the plant materials were barley straw, banana skin, orange peel and many more. It was also showed that the ability of the plant material, especially barley straw to control cyanobacteria might likely involved complex microbial degradation and enhanced by fungal degradation. Therefore, experiments were set up to test the effect of fungi-degraded palm oil trunk on cyanobacterial growth. Methodology and results: In the study, 1 g of palm oil trunk was pre-treated with fungus Lichtheimia sp, for 30 days to allow degradation to occur. After the incubation, the fresh and degraded palm oil trunk was introduced to cyanobacterial culture for 30 days. Growth of culture were estimated based on its chlorophyll a concentration. This study showed an increase ability of fungi-degraded palm oil trunks in inhibiting cyanobacterial growth. Conclusion, significance and impact of study The results strengthened the theory of involvement of microbial degradation in controlling cyanobacterial growth.

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Purification and characterization of dehalogenase from Bacillus cereus SN1 isolated from cow dung

Siti Nurul Fasehah Ismail ; Mohamed Faraj Edbeib ; Wan Mohd Khairul ikhsan Wan Seman ; Mahzan Md. Tab ; Farahayu Khairuddin ; Amin Retnoningsih ; Roswanira Abdul Wahab ; FahrulHuyop

Malaysian Journal of Microbiology.2018;14(3):244-253.

Aims: This study was aimed to characterize a dehalogenase derived from Bacillus cereus SN1 isolated from cow dung. Methodology and results: Cell-free extract of Bacillus cereus SN1 was purified using ion exchange and gel filtration chromatography. Fraction B2 of gel filtration gave the highest enzyme specific activity (0.155 μmol CI¯/min/mg). The results of SDS-PAGE showed the enzyme was 25 kDa in size. The enzyme reached its optimum activity at 30 °C at pH 6, and was inhibited by Mercury(II) sulfate (HgSO4). The Km and kcat values were 0.2 mM and 1.22/sec, respectively. The partial dehalogenase gene sequence was amplified using Group I dehalogenase primers. The amplified gene sequence was designated as DehSN1. Conclusion, significance and impact of study Dehalogenase from Bacillus cereus strain SN1 revealed new characteristics of dehalogenase protein. The findings indicated that the DehSN1 dehalogenase is a promising candidate for further studies as a bioremediation agent for agricultural applications.

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Antibacterial potential of lactic acid bacteria isolated from local pickled Eleiodoxa conferta (kelubi) against selected foodborne pathogens

Nur Ilida Mohamad ; Musaalbakri Abdul Manan ; Norrakiah Abdullah Sani

Malaysian Journal of Microbiology.2018;14(6):490-496.

Aims: Pickled fruits are a popular condiment not only in Malaysia but throughout the world. Lactic acid bacteria (LAB) are known to be able to produce several antibacterial compounds during the pickling process. Pickled Eleiodoxa conferta or kelubi is among the commonly consumed pickled fruits in Malaysia and may be a promising source of LAB. This study was carried out to isolate and identify LAB from local pickled E. conferta and to determine their antibacterial activity against foodborne pathogens. Methodology and results: The isolation of LAB was conducted using standard methods and the isolated colonies were preliminarily identified based on their morphology on De Man, Rogosa and Sharpe (MRS) agar, Gram-positive staining characteristics and their catalase-negative reactions and subsequently chosen for identification with polymerase chain reaction (PCR) amplification of the 16S rRNA gene and sequencing. A total of four LAB isolates were successfully isolated and identified: Lactobacillus brevis (LABK1 and LABK2), L. plantarum (LABK3) and Leuconostoc mesenteroides (LABK4). The antibacterial activity of the identified LAB was determined against 10 commonly known foodborne bacterial pathogens using LAB cell cultures by agar spot test method. The antibacterial activity was also evaluated using the cell free supernatant (CFS) of the LAB through agar well diffusion method. All four LAB cultures were able to demonstrate antibacterial activity and inhibited five Gram-positive and five Gram-negative bacterial pathogens. Conclusion, significance and impact of study This study demonstrated that the isolated LAB from E. conferta has antibacterial effects against several foodborne pathogens. These LAB strains may have potential as a natural food preservative.

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This study demonstrated that the isolated LAB from E. conferta has antibacterial effects against several foodborne pathogens. These LAB strains may have potential as a natural food preservative.

Nur Afifah Binti Jamil ; Abeer Ameen Baqer ; Siti Noor Adnalizawati Adnan ; Ainulkhir Hussin ; Norefrina Shafinaz Md. Nor

Malaysian Journal of Microbiology.2018;14(6):563-569.

Aims: The aim of the study was to isolate and characterise bacteriophages specific to Pseudomonas aeruginosa carrying virulence genes. Methodology and results: Four clinical strains of P. aeruginosa CL1, CL2, CL3 and CL4 were obtained from Queen Elizabeth Hospital, Kota Kinabalu, Sabah. The bacterial strains were screened for virulence genes exoS, toxA and oprI and biofilm production. Six P. aeruginosa specific bacteriophages, namely PAtk1, PAtk2, PAtk3, PAtk4, PAtk5 and PAtk6, were isolated from Tasik Kejuruteraan, Universiti Kebangsaan Malaysia. These bacteriophages were screened for lytic spectrum against P. aeruginosa and two species of Enterobacteriaceae (Escherechia coli and Salmonella Typhi). PCR results showed that all strains possessed exoS, toxA and oprI genes except CL2 that lacked exoS. Nevertheless, it was CL2 that produced the highest biofilm density. Further, based on Transmission Electron Microscopy, PAtk15 and PAtk6 were classified into the family Myoviridae and Siphoviridae, respectively. Among all six isolated phages, only PAtk4 and PAtk6 showed the broadest lytic spectrum in which lytic activity was observed against all clinical P. aeruginosa strains. Conclusion, significance and impact of study In this study we reported the isolation of six bacteriophages from Myoviridae and Siphoviridae that are specific to P. aeruginosa possessing exoS, toxA and oprI genes. Bacteriophages Patk4 and PAtk6 were able to infect all four strains of P. aeruginosa, making these phages potential agents in combating infections by the bacterium.

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Virucidal properties of Orthosiphon stamineus against Herpes Simplex Virus Type 1 (HSV-1)

Nur Suhana Mohamad Ripim ; Norefrina Shafinaz Md Nor

Malaysian Journal of Microbiology.2018;14(6):570-578.

Aims: Phytochemical analysis showed Orthosiphon stamineus (OS) possessed bioactive compounds with antiviral properties against Herpes Simplex Virus Type 1 (HSV-1). However, there isn’t any study reported so far on OS virucidal properties towards HSV-1. Thus, this study aims to investigate virucidal mechanism of OS aqueous extract that possibly acts as a potent entry inhibitor against HSV-1 infection. Methodology and results: Virucidal attachment and penetration assays were done via plaque assay to investigate the virucidal anti-HSV-1 mechanism of OS. The aqueous extract of OS leaves (OSA) was found to reduce HSV-1 plaques in virucidal assays. Inhibitory effect by OSA was observed as early as 30 min after exposing OSA to HSV-1 in a concentration-dependent manner suggesting a direct anti-HSV-1 property of OSA. Further investigation of the stages in which OSA inhibits HSV-1 shows virions treated with OSA failed to attach onto the host cell which implicated a role of OSA in blocking HSV-1 attachment to its host. OSA was also found to reduce HSV-1 plaques in penetration assay. Further evaluation using transmission electron microscopy (TEM) on OSA treated virion showed defective HSV-1 virion without envelope and the remaining capsid was altered. Conclusion, significance and impact of study These findings concluded that Orthosiphon stamineus leaves extract have virucidal activity by disintegrating HSV-1 virion structure and interfering with the attachment and penetration of the virus into the host cell. Thus, through the new mechanism against HSV-1, OS has the potential to be further developed as an anti-HSV-1 agent.

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Comparison of gel-aided sample preparation (GASP) and two in-solution digestion workflows for proteomic analysis using Saccharomyces cerevisiae lysate

Nashriq Mohammad Jailani ; Asmahani Azira Abdu Sani ; Roman Fischer ; Honglei Huang ; Wan Mohd Aizat ; Sheila Nathan ; Holger B. Kramer ; Benedikt M. Kessler ; Mukram Mohamed Mackeen

Malaysian Journal of Microbiology.2018;14(6):579-584.

Abstracts Using Saccharomyces cerevisiae lysate, two in-solution trypsin digestions (chloroform-methanol-water precipitation and RapiGest) were compared to the recently reported gel-aided sample preparation (GASP) workflow. Our proteomic results showed that GASP afforded the highest number of overall protein identifications and peptide spectrum matches without systematic bias towards peptide or protein size.

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The importance of GDN motif in domain III and GXGXG motif in domain VI of L protein in replication of Nipah virus

Siti Aishah Jalani ; Nazlina Ibrahim

Malaysian Journal of Microbiology.2018;14(6):585-589.

Abstracts This study aims to determine the importance of conserved GDN motif in domain III and GXGXG motif in domain VI in Nipah virus (NiV) L protein. Four mutated L genes produced in an earlier study were inserted individually into plasmid pCITE. Optimised transfection protocol was successful in transfecting these plasmids, two helper plasmids (coding for N and P protein), NiV minigenome containing chloramphenicol acetyltransferase (CAT) reporter gene and T7 promoter. Successful in vitro transcription/translation in the NiV minireplicon system was monitored by CAT expression. In conclusion, GXGXG motif was important in the NiV minireplicon system but change of GDN motif does not affect L protein.

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