MALAYSIAN JOURNAL OF MICROBIOLOGY
2019 - Volume 15
Aims: Senna siamea has various medicinal functions but specific studies pertaining to the antioxidant and antibacterial potential that are related to ultrasound-assisted extraction from S. siamea have not been found to be reported yet. Therefore, this research was to determine antibacterial activities and antioxidant of S. siamea leaf extracts using solvent extraction and ultrasound-assisted extraction.
Methodology and results: Antibacterial activities were tested using the disc diffusion method and MIC and MBC values of seven bacterial strains. The ultrasound-assisted extraction extract had a higher yield, total phenolic content, antioxidant activities, and antibacterial activity than solvent extract. Interestingly, the strains of Staphylococcus sp., V. parahaemolyticus, E. coli, and S. enteritidis were not inhibited by the solvent extracts, but were significantly (p < 0.05) inhibited by the ultrasound-assisted extraction extracts. Besides, the MIC and MBC values of extracts from ultrasound-assisted extraction were lower than the extracts from solvent extraction.
Conclusion, significance and impact of study: The results revealed that extracts from ultrasound-assisted extraction have higher efficiency to treat bacterial strains due to the efficiency of extraction method towards the recovery and solubility of extractable compounds. The results concluded that the extracted using ultrasound-assisted extraction can be used as active pharmaceutical components for the treatment, prevention, and control of pathogenic bacteria, including to be applied as food ingredients
Aims: Rhizome of turmeric is known to possess therapeutic activities and has been used in medical practice as an anti-diabetic, hypolipidemic, hepatoprotective, anti-diarrheal, and anti-asthma agent. This study was designed to investigate the anti-inflammatory and antimicrobial activities of Curcuma longa.
Methodology and results: Rhizomes of Curcuma longa (Turmeric) purchased from markets in Ado-Ekiti, Nigeria, were analysed for anti-inflammatory and anti-microbial properties, as well as phytochemical constituents. The in vitro anti-inflammatory activities of the C. longa methanol extract (CLME) were evaluated by albumin denaturation, proteinase inhibitory activity, membrane stabilization, and anti-lipoxygenase activity, at different concentrations using Aspirin, Diclofenac sodium and Indomethacin as standard drugs. The in vitro antimicrobial activities of CLME were carried out on five pathogenic microbes namely Escherichia coli ATCC 29929, Staphylococcus aureus ATCC 29293, Salmonella typhimurium ATCC 14028, Klebsiella pneumoniae ATCC 4252 and Candida albicans ATCC 10231, using both agar well diffusion and broth dilution techniques. A S. typhimurium infected rat model was used for in vivo antimicrobial studies. Phytochemical analyses showed that C. longa rhizomes contain high concentrations of alkaloids, flavonoid and saponins, with moderate levels of phenols, tannin and ferric reducing antioxidant power. CLME was found to be rich in alkaloids, tannins, phenols, steroids, saponins, terpenoids, flavonoids and reducing sugars. CLME showed potent anti-inflammatory activities, and the results compared favourably with the standard anti-inflammatory drugs used. C. longa methanol extract significantly inhibited albumin denaturation and proteinase activity, stabilized membrane of red blood cell from haemolysis in heat and hypotonic conditions, as well inhibited lipoxygenase activity; all of which are associated with inflammatory processes. CLME was found to possess high in vitro antimicrobial activities against the five microorganisms tested. Rats orally infected with S. typhimurium, demonstrated bacteraemia five days post infection, with a total clearance of bacteraemia within 3-5 days following oral administration of CLME. The infected rats treated with CLME equally showed significant improvement in some haematological indices compared to infected rats that were not treated with CLME.
Conclusion, significance and impact of study: The results also showed that methanol extract of C. longa rhizome effectively cured with S. typhimurium infected rats. The overall results suggest that Curcuma longa is a potential source of anti-inflammatory and antimicrobial agents.
Aims: The aim of this study was to evaluate some chemical properties and the cytotoxic effect of aqueous and ethanolic crude polysaccharides extracted from five Lentinus spp. on human cancer cell lines. It was hypothesized that other species of the genus Lentinus could show the pharmacological actions as presence in L. edodes, especially anticancer properties.
Methodology and results: Crude extracts of dried fruit bodies and mycelia from L. edodes, L. sajor-caju, L. swartzii, L. squarrosulus and L. velutinus were extracted using two solvents, hot water and 95% ethanol, and evaluated for their total carbohydrates, proteins, reducing sugar, phenol contents, and cytotoxicity. The yield of crude extracts was 33.6 – 205.3 mg/g dry weight of a sample. Cytotoxicity was determined with 10 mg/mL of crude aqueous and 1 mg/mL of crude ethanolic extracts by using the [3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide] (MTT) method. All extracts showed non-cytotoxicity against the normal cell lines, LLC-MK2 and L929 cells. While, the extracts of L. edodes, L. sajor-caju, L. squarrosulus and L. velutinus displayed the cytotoxicity against the human cancer cell lines.
Conclusion, significance and impact study: The crude aqueous and ethanolic extract from fruit bodies of L. velutinus and the ethanolic extract from fruit bodies of L. sajor-caju and L. squarrosulus displayed the adverse effect against the human cancer cell lines. Hence, these extracts are a potential source of bioactive compounds for cancer treatment.
Aims: The aim of this study was to isolate the endophytic fungi from C. roseus and screen the cytotoxicity and antimicrobial activity of alkaloids extracted from these fungi.
Methodology and results: A total of 56 endophytic fungal isolates were screened from C. roseus plant parts. A. fumigatus and F. oxysporum were the most frequent species. Determinations of alkaloids extracted from the most dominant endophytic fungal species were done. The highest significant total alkaloids productions were by A. fumigatus and A. niger, while the least significant one was by Botrytis cinera. Antimicrobial assay of endophytic fungal extracts indicated that both A. niger and F. oxysporum exhibited significant antimicrobial activities, while A. fumigatus exerted the least activity. In vitro cytotoxicity assay of the endophytic fungal extracts was done against human breast cancer (MCF-7) and liver cancer (HEPG-2) cell lines using SRB assay method. A. niger extract showed potential cytotoxic effect on MCF-7 cell line with IC50 value of 42.1 µg/mL, while the least cytotoxic effect was exhibited by F. oxysporum on MCF-7 cell line with IC50 value of 66.9 µg/mL. Gas Chromatography Mass Spectroscopy (GC-MS) was used for analysis of alkaloids in mycelial and filtrate extracts of A. niger, where eleven compounds were detected.
Conclusion, significance and impact of study: Alkaloids extracted from Catharanthus roseus associated endophytic fungi had cytotoxic and antimicrobial activities.
Aims: The use of rhizobacteri as biofertilizer may help plants in obtaining nutrients from soil. A consortium inoculant (co-inoculant) consisting of nitrogen fixing and phosphate solubilizing bacteria is formulated to maintain its ability as booster of plant growth. This is easy to be stored and applied on plants. The aims of the study were to formulate rhizobacterial co-inoculant and its application on chili plants at greenhouse experiment.
Methodology and results: Isolates of Burkholderia cepacia KD 2.10, Serratia marcescens KAHN 15.12, and Bacillus thuringiensis SAHA 12.12 which have the ability in fixing nitrogen and solubilizing phosphate were used in this study. The three isolates did not show antagonistic activity and hypersensitivity reaction on chili plant. Biofertilizer as carrier material with talc-based powder was mixed with three isolates. This 109 CFU/g cell population of rhizobacterial consortium could be maintained up to six months of storage. Based on result of completely randomized design (CRD) using two factorials and four replicates, application of rhizobacterial co-inoculant significantly affected plant height, number of leaves, flowering age, dry weight of upper plant and root, and root length of chili plant.
Conclusion, significance and impact of study: Rhizobacterial co-inoculant was effective as biofertilizer to improve the growth of chili plants and it reduced the use of chemical fertilizer.
Aims: Present research is focused on the molecular level characterization of drug-resistant L. monocytogenes identified from food and water samples from Tamil Nadu, India.
Methodology and results: A total of 39 food and water samples were collected from local markets and retail shops in Tamil Nadu, India and processed for the isolation and identification of bacteria. Morphology of the bacteria was analysed under a fluorescent microscope. Isolated bacteria were serotyped and screened for the presence of virulence-associated genes haemolysin (hlyA) and invasive associated protein (iapA) by Real-time polymerase chain reaction. The qPCR positive isolates were also typed by random ampliﬁed polymorphic DNA–PCR for epidemiological study. Antibiotic resistance test was done with 16 commercial antibiotics by disc diffusion method. A total of 8 (20.51%) L. monocytogenes were identified belonging to the serotype group 1/2a, 1/2b, 1/2c and 4b. PCR assays revealed the presence of hlyA (456 bp) and iapA (131 bp) genes. In RAPD, OPA-10 primer was found to generate the distinct polymorphic fragment among the isolates. All the isolates were 100% resistant to rifampicin, co-methoxazole, linezolid and oxacillin and 100% sensitive to tetracycline and chloramphenicol. Tetracycline and chloramphenicol are suggested to be a very effective antibiotic against the tested L. monocytogenes isolates.
Conclusion, significance and impact of study: The hlyA and iapA based quantitative PCR technique could be a rapid molecular technique for the detection of L. monocytogenes used in this study. Serotyping along with RAPD-PCR was able to discriminate between the isolates and therefore could serve as a robust and sensitive tool for typing antibiotic-resistant strains of L. monocytogenes.
Keywords: L. monocytogenes, Antibiotic resistant, PCR, RAPD, Serotyping
Aims: Bacterial vaginosis (BV) is characterized by a transition in vaginal microflora from lactobacilli to anaerobic bacteria. Gardnerella vaginalis and Atopobium vaginae are considered the most responsible pathogens for the etiology of BV. Colonization of male urethra with BV-associated bacteria has been rarely investigated. The aim of this study was to investigate the differences in the presence of BV-associated bacteria in the healthy male urethra in regard to sexual exposure.
Methodology and results: The first-catch urine specimens, representative of urethral swabs, from 114 healthy male volunteers, were included in this study. Lactobacillus spp., L. crispatus, L. jensenii, L. gasseri, L. iners, G. vaginalis, A. vaginae, Peptoniphilus spp., P. lacrimalis, BVAB2, Mageeibacillus indolicus, Megasphaera type I, Mobiluncus mulieris, Leptotrichia/Sneathia, Corynebacterium spp., and Prevotella spp. were investigated using a PCR assay. The most frequently identified BV-associated bacteria were Lactobacillus spp., Peptoniphilus spp., and G. vaginalis. There was no association between any BV-associated bacteria and sexual exposure. There was statistically significant co-occurrence of A. vaginae and G. vaginalis in the MU of subjects independently of sexual exposure (p=0.025). Also, there was a significant association between G. vaginalis and smoking (p = 0.023).
Conclusion, significance and impact of study: To the best of our knowledge, this is the first study reporting the co-occurrence of G. vaginalis and A. vaginae in the male urethra independently of sexual exposure.
Keywords: Male urethra, bacterial vaginosis, Atopobium vaginae, Gardnerella vaginalis, sexual exposure
Aims: Biofilm formation by Methicillin-resistant Staphylococcus aureus on a variety of surfaces and detection of the biofilm-forming population by the most reliable method is very much essential to diagnose the nosocomial infection caused by S. aureus.
Methodology and results: This study is aimed to evaluate the biofilm producing ability of S. aureus by qualitative Congo red agar (CRA), and quantitative microtitre plate (MTP) methods. The morphological difference of biofilms analysis was done by SEM (Scanning Electron Microscope) and genotyping analysis of mecA and femA for determination of MRSA among isolated S. aureus strains and to check the biofilm producers among MRSA strains. Biofilm production was found to be at different intensities by MTP. The strong, moderate and weak biofilm producers were found to be 38.63%, 31.81%, and 29.54% respectively. The strong adherent biofilm formed by representative isolate developed a dense biofilm with thick mucus three-dimensional multilayered structure of macroscopic dimension. Conversely, SEM analysis of moderate and weak biofilm representative strain failed to form a monolayer of scattered single cells to three-dimensional structure. The 47.72% of S. aureus isolates have shown positive for the genotypic analysis of mecA and femA. The strong and moderate biofilm forming MRSA was found to be 38.63% and 9.09%, respectively.
Conclusion, significance and impact of study: The great challenge is associated with biofilm mediated infection caused S. aureus healthy and hospitalized individual hence the present study reinforces the need of precautionary measures to avoid the indiscriminate use of antibiotics in case of biofilm-forming MRSA.
Aims: Microbiota endogenous to oleaginous plants have attracted special attention in recent years for their
biotechnological potentials and applications including the production of biodegradable biopolyester poly(3-
hydroxybutyrate) [P(3HB)] as an alternative to thermoplastics. The present study is aimed to screen the endophytic
bacteria of selected oleaginous plants such as Arachis hypogaea L., Brassica napus L., Brassica nigra L., Helianthus
annuus L., Ricinus communis L. and Sesamum indicum L. for the production of P(3HB).
Methodology and results: Bacteria endogenous to the oleaginous plants were isolated from surface sterilized healthy
tissues following sterilization with 70% ethanol and 0.5% sodium hypochlorite and screened for P(3HB) production in
mineral salts medium. Nile blue A staining method was used for detection of intracellular P(3HB), while the accumulated
biopolyester was quantified spectrophotometrically following chemical conversion to chrotonic acid by treating with
sulfuric acid. Five potent P(3HB) accumulating isolates have been selected and identified as Cellulosimicrobium
cellulans AHS 01 (KX458038), Beijerinckia fluminensis AHR 02 (KX458039), Exiguobacterium acetylicum BNL 103
(KX458037), Bacillus toyonensis BNS 102 (KX458036) and Bacillus cereus RCL 02 (KX458035) based on
morphological, physio-biochemical and 16S rDNA sequence analysis. These endogenously growing bacterial isolates
accumulated intracellular biopolyester accounting 43-62% of their cell dry weight (CDW) when grown in mineral salts
medium supplemented with yeast extract. Intracellular accumulation of P(3HB) by these isolates have also been
confirmed by FTIR spectral analysis of lyophilized cell mass and 1HNMR spectra of the extracted polymer.
Conclusion, significance and impact of study: These findings, first of its kind point to exploration of endogenous
bacterial communities of oil-producing plants as a potential bioresource for production of P(3HB) bioplastics in a
Aims: Arbuscular mycorrhizal is an obligate mutualistic symbiosis fungus which survives by forming endomycorrhizal on
plant roots. The arbuscular mycorrhizal fungi are not host-specific, allowing them to form a mutualistic symbiosis with a
wide range of host plants including oil palm. In Malaysia, the arbuscular mycorrhizal fungi are used as a growth
enhancer for the oil palm: Elaeis guineensis. The arbuscular mycorrhizal fungi are introduced only during transplantation
to the field when the ages of the seedlings are approximately one year old. As such, this study is designed to investigate
the ability of the arbuscular mycorrhizal fungi to form colonisation with pre-nursery oil palm seedlings.
Methodology and results: Here, the arbuscular mycorrhizal fungi were introduced at the pre-nursery stage oil palm
seedlings. After inoculation, the seedlings were harvested on different days, i.e. on day-3, day-7, day-14, day-21, day-40
and day-60 to determine the colonisation of arbuscular mycorrhizal fungi. We found that the arbuscular mycorrhizal fungi
are able to form a mycorrhizal association with the oil palm seedling at the pre-nursery stage after 40 days of
inoculation, and the arbuscular mycorrhizal fungi that formed the association are Glomus sp. and Scutellospora sp.
Conclusion, significance and impact of study: This study suggested that the oil palm seedling can be made into a
mycorrhizal plant as early as the nursery stage before transplanting them into the plantation.
Aims: Although several major food poisoning outbreaks caused by Staphylococcus aureus have been reported, monitoring of this pathogen is often neglected. The objectives of this study were to assess the contamination level of S. aureus and characterize the S. aureus isolated in ready-to-eat (RTE), food handlers, food contact surfaces, and table cleaning cloths (TCC).
Methodology and results: A total of 150 RTE foods, 59 food contact surfaces (FCS) and 34 table cleaning cloths (TCC) from food premises were examined. The contamination level of S. aureus in RTE foods was at acceptable level. However, more than 10% of the FCS and TCC were contaminated with high levels of S. aureus (>1.0 Log CFU/cm2, >2.7 Log CFU/piece). Eighty-one isolated S. aureus including those isolated from hands of food handlers were further characterized by antimicrobial susceptibility testing, virulotyping and PFGE. Out of 81 isolates, only three were multidrug resistant. More than 96% (n = 78) of the S. aureus harboured at least one virulence gene. Almost half of the isolates carried at least one staphylococcal enterotoxin in which SEC was the most common enterotoxin detected. Conclusion, significance and impact of study: The PFGE analysis showed that the S. aureus could be disseminated via the FCS, TCC and the hands of food handlers. Therefore, this study reiterates the importance of proper hand washing, sanitation of FCS and TCC, as well as continuous monitoring on S. aureus in food and the food handlers.
Keywords: genotyping, Staphylococcus aureus, ready-to-eat foods, virulence
Aims: Dendrobiums are majorly affected by Fusarium proliferatum and F. oxysporum. The aim of this research was to utilise the mycotoxin, fusaric acid (FA) on Dendrobium hybrid to produce cultivars that are resistant towards these fungi.
Methodology and results: FA of concentrations 0.05, 0.10, 0.15 and 0.20 mM were transferred to sterilised half-strength Murashige and Skoog (MS) medium and inoculated with four weeks old thin cell layer (TCL) of protocorm-like bodies (PLBs) for eight weeks. It was deduced that PLBs treated with 0.10 mM of FA resulted in highest survival and shoot regeneration rate but the survival and regeneration rate began to decline as the concentrations of FA were increased. Histology and scanning electron microscopy (SEM) observation showed prominent cell damage and stomatal closure in PLBs treated with FA. Direct amplification of minisatellite DNA (DAMD) markers showed polymorphism in the FA treated PLBs compared to the control PLBs. In the leaf bridge bioassay, plantlets treated with 0.05 mM of FA showed most resistance towards both fungal species.
Conclusion, significance and impact of study: Therefore, this research is a preliminary screening study where the optimum concentration of FA was selected based on the reaction of treated TCL of PLBs towards these mutagens.
Keywords: Orchid, fusaric acid, tissue culture, resistant, stomatal closure
Preliminary study on the effects of fusaric acid treated protocorm-like bodies of Dendrobium hybrid against Fusarium proliferatum and Fusarium oxysporum
- Siva Sangu, S. , Mohamed Nor, N. M. I., Zakaria, L., Mohamad, A., Subramaniam, S.
Aims: An actinomycete strain, designated KBS50, was isolated from a beach sediment sample collected from the Santubong area in Sarawak, Malaysia. This study reports on the identification, characterization and evaluation of the antimicrobial potential of this rare actinomycete.
Methodology and results: KBS50 was identified as a potentially new species of Plantactinospora genus using the 16S rRNA gene sequence analysis. The rare actinomycete showed distinct morphological and physiological characteristics from other species of Plantactinospora. KBS50 exhibited strong antagonistic activities against Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and fungi (Aspergillus niger, Ganoderma boninense, and Rhizoctonia solani). The actinomycete also tested positive for proteolytic activity. Meanwhile, secondary screening of the cell-free culture broths and the ethyl acetate crude extracts detected antimicrobial activity against the Gram-positive bacteria only. The minimum inhibitory concentration of the crude extract against B. subtilis and S. aureus was 5.21±1.30 µg mL-1 and 15.63±0.00 µg mL-1, respectively.
Conclusion, significance and impact of study: The results presented in this paper provided an insight into the capability of Plantactinospora sp. KBS50 as a potential source of bioactive secondary metabolites compounds. This study also showed that the marine-associated environment such as the coastal area in Sarawak can be a valuable source of unique actinomycetes that can be exploited for natural product discovery.
Keywords: Marine actinomycete, proteolytic, secondary metabolites, natural product
Aims: Reducing indiscriminate and over use of antibiotics and chemical preservatives, finding better probiotics and new bacteriocins should get paramount importance which will eventually contribute to save lives of newborn to elderly. Some probiotic Lactobacillus produces bacteriocins or bacteriocin-like-substances (BLS) which may be considered as candidates for biopreservatives. The aims of this study was to find probiotic Lactobacillus and assessing their bacteriocinogenic activity.
Methodology and results: Five vegetables were processed and isolated 38 Lactic acid bacteria (LAB) by using De Man Rogosa Sharpe (MRS) medium. Among 38 LAB, only 8 (21%) showed potential antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Salmonella Typhii in agar well diffusion method. Finally, we selected two Lactobacillus species such as Lactobacillus plantarum MG1 and Lactobacillus delbrueckii MT4 for further in vitro testing. Both isolates showed growth capability at wide range of temperatures (27-45°C), pH (2-9), NaCl (1-7%), bile salt (0.5-2%) and could produce bacteriocin or BLS; which indicated they have potentiality to be probiotic. Bacteriocin or BLS produced by L. plantarum inhibited E. coli and S. Typhii whereas bacteriocin or BLS of L. delbrueckii inhibited S. aureus, E. coli and S. Typhi. These crude bacteriocin or BLS reduced initial bacterial load of vegetables up to 79% after 48 h while 5% of its mixed with vegetables in room temperature.
Conclusion, significance and impact of study: The study showed that our isolated L. plantarum and L. delbrueckii could be used as probiotic to improve public health and their bacteriocin or BLS could be used as biopreservatives.
Keywords: Probiotics, bacteriocin, biopreservatives, lactic acid bacteria, Antimicrobials
In vitro evaluation of probiotic and bacteriocinogenic potentiality of Lactobacillus plantarum and Lactobacillus delbrueckii isolated from vegetables in Chittagong region, Bangladesh
- Rahman, M. M., Ferdouse, J., Akter, R., Uddin, M. S., Aktar, S., Paul, S. C., Anjum, K. I., Mithun, M., Anwar, M. N.
Aims: The objective of this study is to investigate the potential of fungi isolated from forest soil as biocontrol against Ganoderma boninense, the causal pathogen of basal stem rot disease in Elaeis guineensis Jacq. (oil palm).
Methodology and results: Total 195 isolates were isolated from 20 soil samples collected from Crocker Range of Sabah and 54 fungal isolates were identified with 14 of them showed Percentage Inhibition of Radial Growth (PIRG) greater than 50%. A potential fungi (F15) with PIRG of 84.85% was later identified as Penicillium simplicissimum using molecular technique. Microscopy examination on P. simplicissimum and G. boninense interaction showed the evidence on the damage of pathogen hyphae when challenged by P. simplicissimum. The secondary metabolites of P. simplicissimum which may possibly contributed to this observation were later extracted using hexane, ethyl acetate and acetone and the extracts were tested in agar dilution bioassay (0.2 mg/mL to 1.0 mg/mL) against the pathogen. Ethyl acetate extract gave the highest inhibition to G. boninense (14.12 % in 0.4 mg/mL of ethyl acetate extract).
Conclusion, significance and impact of study: This is the first report, on the bioactivity of P. simplicissimum isolated from Crocker Range of Sabah against Ganoderma boninense, the causal pathogen of basal stem rot disease. Overall, our results indicated that P. simplicissimum has the potential to be further investigated as a biocontrol agent against G. boninense.
Keywords: Basal stem rot, oil palm, Ganoderma boninense, Penicillium simplicissimum
Aim: The increased importance of biosurfactant in the recent past is mainly due to their applications in various industries ranging from petroleum to pharmaceuticals. Their biodegradability and environmental compatibility with low toxicity makes it even more interesting. Microbial production of biosurfactant is found to be a viable option as they are diverse, eco-friendly, facilitate large scale production, ability to perform under extreme conditions etc. One class of microbes that is endophytes are known to show great potential in producing different varieties of medically and industrially significant biological compounds. The present study focuses on the screening and production of biosurfactant from endophytic bacteria.
Methodology and results: Of all the isolates tested, one endophyte identified as Bacillus cereus HM998898 was found to produce maximum biosurfactant. Statistical method Plackett burman was used to optimize the media for the maximum production and the ideal composition was found to be KNO3 (1g/l), Gingley oil (2ml), K2HPO4 (2.5g/l), KH2PO4 (0.75g/l), MgSO4.5H2O (0.5g/l), FeSO4.7H2O (0.005g/l) and NaCl (0.025g/l). The extracted biosurfactant was characterized and was identified to be glycolipid. This was further tested for biocompatibility against Fibroblast cell (3T3) cells and was evaluated for their anti tumor activity against Hep2 cells.
Conclusion, significance and impact of study: The biosurfactant produced was found to induce toxicity to cancer cells at appreciable levels while they remained non-toxic to normal cells supporting the possible applications of biosurfactant in medical field.
Keywords: Endophytic bacteria, Bacillus cereus, biosurfactant, Plackett-Burman design, cytotoxicity
Aims: Campylobacter is a major cause of gastroenteritis in humans worldwide, particularly in developed countries and is reported to show an increased trend in antibiotic resistance. The purpose of this study was to determine the occurrence of Campylobacter in wild birds, poultry and in poultry environments in Selangor, Malaysia as well as to determine the rate of antibiotic resistance among Campylobacter isolates from poultry and wild birds.
Methodology and results: The wild birds were trapped near poultry farm areas and in open areas which were more than 5 km away from poultry farms (referred to as open environment). Of 57 birds trapped near the farm’s environment, 17.5% were positive for Campylobacter and out of these, 90% were C. jejuni. Of a total of 77 birds in the open environment, 22.1% were positive for Campylobacter and 88.7% were C. jejuni. The poultry farms consisted of 3 chicken and 2 duck farms. About 60% of the chickens and 44.8% of the ducks were positive for Campylobacter of which 80% were C. jejuni, while 20% were C. coli. The Campylobacter isolates were subjected to antibiotic susceptibility test using disk diffusion method against 12 antibiotics. All the isolates (100%) from wild birds around poultry houses were resistant to at least one antibiotic.
Conclusion, significance and impact of study: The findings showed 93% of the isolates from wild birds were resistant to at least two antibiotics. Campylobacter isolates from poultry in the farms were resistant to at least one antibiotic. The antibiotic resistant Campylobacter is of public health importance.
Keywords: antibiotic, resistance, Campylobacter, poultry, wild birds
Aims: Benzalkonium chloride is used to disinfect hospital instruments to prevent nosocomial infection caused by microorganisms, such as Methicillin Resistant Staphylococcus aureus (MRSA). There are strains of MRSA isolated from hospitals that were found to be resistant towards benzalkonium chloride. This research was aimed to compare the affectivity of different concentrations of benzalkonium chloride to inhibit the growth of Hospital-Associated MRSA (HA-MRSA) and determine the Minimum Inhibitory Concentration (MIC) of benzalkonium chloride against HA-MRSA.
Methodology and results: The samples were five HA-MRSA isolates obtained from Dr. Soetomo Hospital Surabaya. It was identified by amplification of SCCmec genes. The HA-MRSA with SCCmec type III was divided into six flasks based on the concentration of benzalkonium chloride in their inoculation media (0 μg/mL, 0.625 μg/mL, 1.25 μg/mL, 2.5 μg/mL, 5 μg/mL, and 10 μg/mL). The growth of HA-MRSA in media was determined by the number of colonies after treatment. The result showed that the MIC of benzalkonium chloride for HA-MRSA was 5 μg/mL, where no growth of bacterial was observed. There was significant difference in MRSA colony count between different groups of benzalkonium chloride concentrations (P = 0.001), and there was negative correlation between benzalkonium chloride concentration and HA-MRSA growth (P = 0.0001 and r = ─0.880).
Conclusion, significance and impact of study: The concentration of benzalkonium chloride influences the growth of HA-MRSA. The higher the concentration, the fewer HA-MRSA growth. Application of benzalkonium chloride according to MIC will prevent HA-MRSA resistance towards benzalkonium chloride.
Keywords: HA-MRSA, benzalkonium chloride, concentration, MIC
Aims: Aqueous extract of Quercus infectoria (QI) galls has been reported to possess anti-fungal and anti-inflammatory activities. Hence, this study aimed to determine in vitro antimicrobial activity of formulated QI gall extract-based vaginal cream against Candida albicans and to evaluate the possible side effects on the cervicovaginal epithelium of healthy rat.
Methodology and results: Three different cream formulations containing 10%, 20%, and 30% of QI gall extract respectively were tested for their in vitro antimicrobial activity against C. albicans (ATCC 10231) by using disc diffusion test. Microbroth serial dilution method was performed in determining the minimum inhibitory concentration (MIC) and fungicidal concentration (MFC). The 30% formulated extract cream (FEC) was applied topically on the cervicovaginal surface of healthy Sprague Dawley (SD) rats and examined for in vivo local tissue effects histologically. The mean scores of inhibition zone diameter were compared by one-way ANOVA and post-hoc test using PRISM software. All extract cream formulations displayed a relatively good anti-Candida activity. The MIC values exhibited by 10%, 20%, and 30% FEC against C. albicans were 1.094 mg/mL, 0.547 mg/mL, and 0.068 mg/mL, respectively. The 10% and 20% FECs showed a significant difference (P=0.0254) in the mean of inhibition zone diameter. The lowest MFC value (0.068 mg/mL) was shown by 30% FEC. There were no abnormal changes seen at the vagina and cervical mucosa after 2 weeks application of 30% FEC.
Conclusion, significance and impact of study: QI gall extract formulated in cream base has an anti-Candida activity in vitro and may serve as one of the useful potential herbal formulations in the prevention of vaginal candidiasis without causing any unwanted local side effects.
Keywords: Vulvovaginal candidiasis, Quercus infectoria, formulated cream, anti-Candida activity, toxicity
Aims: Wolbachia is an endosymbiont and a gram-negative genus bacterium which has received the spotlight in the field of research studies due to its multiple capabilities to affect it hosts, including the bed bugs (Hemiptera: Cimcidae). While most investigations concentrated on the common bed bugs (Cimex lectularius), no published studies have yet to be done on molecular screenings of Wolbachi aassociated with tropical bed bugs (C. hemipterus). The present study was undertaken to screen Wolbachia infection from tropical bed bugs from Peninsular Malaysia.
Methodology and results: We attempted to screen and characterize Wolbachia infections in tropical bed bugs from 22 different localities throughout Peninsular Malaysia using a molecular approach; multiple Polymerase Chain Reaction (PCR) assays with four sets of primer sequences.
Conclusion, significance and impact of study: Our findings yielded negative results of Wolbachiainfectionsand, therefore,further confirmed that all bed bug samples from all localities in Peninsular Malaysia are free from Wolbachia infections. Our findings also suggested that the prevalence of Wolbachiain tropical bed bug populationsin Peninsular Malaysia is very unlikely.
Keywords: Tropical bed bugs, C. hemipterus, PCR, Wolbachia, molecular detection
Aims: Deoxynivalenol is a type B trichothecene produced by Fusarium graminearum that can cause serious health problems in human and livestock. The present study aimed to reduce and detoxify Deoxynivalenol using a local strain Aspergillus oryzae KKB4 and Rhizopus oryzae KP1R1.
Methodology and results: Corn as solid substrate artificially inoculated with F. graminearum bio 163252 to produced deoxynivalenol. Deoxynivalenol contaminated corn then inoculated with A. oryzae KKB4 and R. oryzae KP1R1. During fermentation, a decrease in deoxynivalenol levels is analyzed including loss of dry matter and glucosamine content. Deoxynivalenol was extracted from the substrate by solid phase extraction and quantified using high-performance liquid chromatography. The reduction of deoxynivalenol by A. oryzae KKB4 and R. oryzae KP1R1 were 65.91% and 56.82%, respectively after ten days of fermentation. Toxicity analysis revealed that residues of deoxynivalenol were not toxic to growth of Saccharomyces cerevisiae cells.
Conclusion, significance and impact of study: Local strains A. oryzae KKB4 and R. oryzae KP1R1 were able to reduce and detoxify deoxynivalenol in solid substrates. This study provides supporting data to control mycotoxin that is critical for food and feed safety.
Keywords: Deoxynivalenol, Aspergillus oryzae KKB4, Rhizopus oryzae KP1R1, solid state fermentation
Aims: Microalgae were very small in size (a few µm) and have a low concentration in the medium. Due to their size, harvesting of microalgae from their growth medium remain a major obstacle in downstream processing. Efficient harvesting method must be applied to ensure it is cost effective, preserves quality and improves the culture process which is important for commercial algal production. Common harvesting methods use to harvest microalgae from their growth medium are centrifugation, filtration, flotation, sedimentation, and flocculation. Flocculation is a common method use to harvest microalgae due to low cost, save time and highly efficient method for algae biomass recovery. The purpose of this study was to investigate the effects chitosan and eggshell on flocculation of microalga Spirulina platensis. Chitosan and eggshell were chosen as flocculant due to their biodegradability, non-toxicity and safe to handle.
Methodology and results: The efficiencies of flocculation process were examined by conducting experiments over a range of culture pH, flocculant concentrations and flocculation time using chitosan and eggshell as flocculant agent. Under optimized flocculation conditions of 50 mg/L chitosan at pH 8 culture media for 90 min of flocculation time and 4 mg/mL eggshell at pH 4 culture media for 8 min of flocculation time, the maximum flocculation efficiency obtained was 79.98±1.65% and 97.17±1.38%, respectively.
Conclusion, significance and impact of study: Therefore, it can be concluded that chitosan and eggshell could be used as flocculants for harvesting large scale microalgal biomass production. Nevertheless, eggshell is more economical and more efficient compared to chitosan in harvesting microalgae biomass.
Keywords: Bioflocculation, Spirulina platensis, chitosan, eggshell, flocculation efficiency
Aims: Pigments are coloured substances that exhibit important characteristics to many industries including food, textile, cosmetics, food, pharmaceutical and also aquaculture industry. Naturally derived pigments from marine bacteria do not only exhibit the tinctorial property but are also known to possess broad range of antimicrobial activities. From the industrial point of view, the necessity to obtain suitable culture conditions for maximum yield of cell growth and pigment production is of utmost importance.
Methodology and results: The effect of cultural conditions, including light, pH, temperature, agitation speed and size of inoculum on bioactivity of an epiphytic marine bacteria, Pseudoalteromonas rubra BF1A IBRL was studied using shake flask technology. The antimicrobial activity was determined using the Lorian method. As a result, prodigiosin pigment extract obtained from P. rubra BF1A IBRL showed inhibitory activity against the MRSA strain. Pseudoalteromonas rubra BF1A IBRL produced the highest level of prodigiosin and anti-MRSA activity (P<0.05) in Marine broth at initial pH of 7.6 incubated at dark condition at temperature of 26 °C, agitation speed of 120 rpm and 2% (v/v) (1 × 106 CFU/mL) of inoculums size.
Conclusion, significance and impact of study: A high correlation between pigmentation and antibacterial activity were observed anticipating that the pigment has its own antibacterial properties. The above findings supported the fact that epiphytic marine bacteria were fruitful source for pigmented bioactive compounds, and the physical parameters had significantly influence of the pigment production.
Keywords: Pseudoalteromonas rubra; marine bacteria; prodigiosin; antibacterial; red pigment
Aims: Distillers dried grains are the nutrient rich co-product of dry-milled ethanol production. The present study aimed to prove that the nutritional composition of distillers dried grain from a crude hydrolysate of rice husk fermented by co-cultures of Saccharomyces cerevisiae with Candida tropicalis difference from unfermented crude rice husk hydrolysate and mono-cultured S. cerevisiae or C. tropicalis.
Methodology and results: The effects of mono- and co-cultures S. cerevisiae with C. tropicalis on the nutrient compositions of distillers dried grain were investigated. The crude rice husk hydrolysate in distilled water contained molasses, urea, sodium nitrate, ammonium nitrate, potassium phosphate and magnesium sulfate heptahydrate were fermented by mono- and co-cultures of S. cerevisiae with C. tropicalis for 7 days at 28-30 °C and stored with a relative humidity of 60-70% in the dark. A mono- and a co-culture fermentation of S. cerevisiae and C. tropicalis increased the crude protein, crude fat, crude fibres, ash, and calcium contents of the rice husk feedstock and decreased the metabolic energy reducing sugars.
Conclusion, significance and impact of study: Some nutrient components of the DDG crude rice husk hydrolysate performed higher than the non-fermentation of rice husks. The finding of this study will serve as a basic reference for future studies to utilize by-product of ethanol production from rice husks for animal feed formulation.
Keywords: Rice husk, distiller dried grain, Saccharomyces cerevisiae, Candida tropicalis
Aims: This study aimed to determine the prevalence of pathogens in urinary tract and their antimicrobial susceptibilities, based on extended-spectrum β-lactamase (ESBL) and AmpC β-lactamase production in Bangladesh.
Methodology and results: The prevalence of pathogenic microorganisms in urinary tract and their antimicrobial resistance patterns were identified in 200 isolates from patients with urinary tract infections. Combined disc diffusion was performed to identify the presence of ESBL-producing strains. Moreover, disc approximation assay, disc potentiation test and double disc synergy test were performed to determine the presence of AmpC β-lactamase producing bacterial strains. This study demonstrated a higher prevalence of UTIs in females (83.5%) than in males (16.5%). The most common pathogen was found Escherichia coli (44.5%), followed by Enterococcus fecalis (24%), Klebsiella pneumoniae (7.5%), Staphylococcus aureus (6%), Pseudomonas aeruginosa (5.5%) and Staphylococcus saprophyticus (4.5%). ESBL and AmpC β-lactamase production occurred more frequently in E. coli (25.84%) and P.aeruginosa (100%) respectively.
Conclusion, significance and impact of study: The result of this study would provide physicians with important information which help them to make a judicious choice of antibiotics for therapeutic purposes. However, it is emphasized that continuous surveillance of antibiogram of medically important organisms causing UTI is necessary for adopting a rational antibiotic policy in the country.
Keywords: Urinary tract infection, ESBL, bacteria, antibiotic resistance
Aims: The objective of this research was to study the effect of bio-liquid organic fertilizer on the growth of Dipterocarpus alatus Roxb seedlings (30 days old) in the pot experiment.
Methodology and results: For the production of bio-liquid fertilizers, distillery slop; molasses and bio-methane waste water were fermented with plant growth promoting bacteria, which had potentials for nitrogen fixing, phosphate solubilizing and potassium solubilizing properties. It was found that treatment no. 13 (molasses + three bacterial isolates (PGPB), 30 days of fermentation) presented the best result on the growth parameters of D. alatus Roxb including root length (21.67 cm), shoot height (20.33 cm), root fresh weight (1.49 g), shoot fresh weight (3.61 g) and total biomass (4.13 g). Moreover, using liquid organic fertilizer produced from molasses supplemented with bacteria had higher growth-promoting effects on D. alatus than the effective microorganisms (EM).
Conclusion, significance and impact of study: To covert agricultural residues to the valuable product was the aim of this work. In our experiment, we found that molasses and bio-methane waste water were suitable for using as a material to produce liquid organic fertilizers which were beneficial for promoting growth of D. alatus seedlings.
Keywords: Bio-liquid organic fertilizer, Dipterocarpus alatus Roxb, seedling, Plant growth promoting microorganisms
Aims: Marine bacteria are a great source of natural pigments, which can be used as coloring agent in food, textile, cosmetics and aquaculture industry to overcome the drawbacks poses by the synthetic pigments. The aims of the study is to identify the potential biopigment producer, determine the antimicrobial susceptibilities, and characterize the pigment produced.
Methodology and results: In this study, the surface attached marine bacteria isolated from the surface of seaweed, Enteromorpha sp. has been identified as Pseudoalteromonas rubra BF1A IBRL through the molecular identification step. This species produced intracellular and extracellular red pigment with antibacterial activity. The susceptible bacteria includes Bacillus subtilis, Bacillus cereus, Methicillin Resistant Staphylococcus aureus, Staphylococcus aureus and also Acinetobacter anitratus with inhibition zone ranges from 7.33 to 10.33 mm, whereas Minimum inhibitory concentration (MIC) values ranges from 0.055 to 8.88 mg/mL. The UV/vis analysis indicated that the maximal absorbance of ISO and DE pigment extract were at 531 and 534 nm, respectively. Based on the antimicrobial activity, the extracellular extract poses greater antibacterial activity, thus was selected as the potential pigment extract and were further evaluated. The Thin Layer Chromatography (TLC) profile of the DE extract showed one major band under visible light ((Rf = 0.87) and the bioautograpgy analysis of the pigmented band showed positive activity against both Gram-positive and Gram-negative bacteria. The pigment in DE extract was identified as prodigiosin based on the spectroscopic properties, presumptive test and HPLC analysis.
Conclusion, significance and impact of study: This study highlights the dual benefits of the P. rubra BF1A IBRL pigment extract, which exhibited both tinctorial and pharmacology benefits, thus it can be act as colouring agent with own preservative value in food, textile, or cosmetics industries.
Keywords: Marine bacteria, Pseudoalteromonas rubra, prodigiosin, antimicrobial activity, biopigment
Aims: Fisheries-based food is needed by humans as a protein source, one of which is salted fish Lutjanus vivanus. Market demand for this product in Indonesia is quite high. The aim of the study was to identify pathogenic bacteria in salted fish Lutjanus vivanus.
Methodology and results: The method used in this study was descriptive method including pathogenic test, bacterial genomic DNA isolation based on 16 sRNA gene using prokaryotic specific primers, namely 63f forward primer (5′-CAG GCC TAA CAC ATG CAA GTC-3′) and reverse 1387r primer (5′-GGG CGG WGT GTA CAA GGC-3′). The results of this study indicated pathogenic bacteria in salted fish Lutjanus vivanus with pathogenic activity of α hemolytic and β hemolytic. The bacteria were identified as Serratia marcescens strain ZK2 16S for isolate KS and Bacillus altitudinis strains A-19 16S for isolate LG.
Conclusion, significance and impact of study: In salted fish Lutjanus vivanus in the Sorong city, West Papua, it was obtained Serratia marcescens strain ZK2 16S with total hemolytic activity and Bacillus altitudinis A-19 16S strain with partial hemolytic activity.
Keywords: Lutjanus vivanus, pathogenic bacteria, West Papua
Aims: To evaluate the anti-leptospiral activity of Canarium odontophyllum leaves against Leptospira interrogans serovar Bataviae and Leptospira borgpetersenii serovar Javanica.
Methodology and results: The extracts (hexane, acetone, methanol and aqueous) used in this study were tested at concentration ranging from 0.049 mg/mL to 25 mg/mL using broth microdilution method. Percentage inhibition (%) was obtained through OD reading at 400 nm. Only methanol extract was incubated with Leptospira to observe population changes under dark field microscope prior to subjected for DNA damaging studies through gel electrophoresis of genomic DNA. Methanol extract showed the highest percentage inhibition of 66% against L.interrogans serovar Bataviae and 74% against L.borgpetersenii serovar Javanica. The IC50 value of methanol extract was 4.60 mg/mL and 2.25 mg/mL against serovar Bataviae and serovar Javanica, respectively. Both Leptospira culture which was treated with IC50 value of methanol extract showed drastic decrease in population compared to untreated Leptospira for both serovar. There was no DNA damage towards serovar Bataviae. However, serovar Javanica exhibited DNA damage as observed from the presence of DNA fragmentation on the gel electrophoresis.
Conclusion, significance and impact of study: These findings confirmed that methanol leaves extract from of Canarium odontophyllum has a potential to control leptospirosis.
Keywords: anti-leptospiral, Leptospira interrogans, Leptospira borgpetersenii, Canarium odontophyllum
Moringa oleifera, considered a medicinal tree by many civilizations, owes its repute to its medicinal attributes, and in particular, to its antimicrobial properties. Different parts of this plant, including pods, stem bark, leaves, roots, and seeds contain bioactive agents such as quercetin, phenolic acids, alkaloids, flavonoids, etc. The modes of action of these bioactive agents are varied, ranging from the inhibition of enzymes to the disruption of bacterial cell membranes. The various antimicrobial properties of the plant are manifested in extracts of methanol, ethanol, hexane, chloroform, and water. Such extracts, which also display antibacterial activity against biofilms, can serve as therapeutic agents against multidrug resistant pathogens, including both Gram-negative and Gram-positive bacteria.
Keywords: Moringa oleifera, antimicrobial properties, Gram-positive bacteria, Gram-negative bacteria, bioactive agent
Aims: To investigate the influence of carbon sources and additives/surfactants on the mycelium growth and exopolysaccharides (EPS) production, including the morphology during submerged cultivation of Pleurotus ostreatus in the minimal-medium as the base medium.
Methodology and results: Pleurotus ostreatus was cultivated in different types of carbon sources to investigate the effects of carbon sources to mycelium growth and changes of mycelium morphology which directly affects the synthesis of EPS. In addition, additives or surfactants can increase the bioavailability of less soluble substrates in the cultured medium for the mycelium growth and indirectly affects the EPS production. In this study, the cultivation of P. ostreatus in the minimal-medium by using glucose as the carbon source with the addition of lecithin at 1 % (w/v) gave the highest EPS production 4.53 ± 0.30 g/L, an increase of about 89.53 % when compared to the cultivation without the addition of lecithin. Addition of lecithin changes morphology of the pellets outer layer and under microscope showing a dense hyphal network surrounding the pellets with the sizes of micro pellets almost 0.5-1.5 mm which contributed to the increase of EPS production after 14 days cultivation at 26 °C.
Conclusion, significance and impact of study: The choice of the carbon source should not only be for high productivity rate of mycelium growth and EPS production, but a cheaper alternative source should also be considered. In conclusion, high mycelium biomass and EPS production was achieved either by changes of the morphology through the type of carbon source and addition of additives such as lecithin.
Keywords: Pleurotus ostreatus, exopolysaccharide, submerged, morphology, additives, biomass
Effects of carbon source and additives on biomass, exopolysaccharide production and morphology of Pleurotus ostreatus in submerged cultivation
- Othman, N. Z., Mohd. Din, A. R. J., Zakaria, K. H. N., Ramli, S., Yeng, L. H., Abd. Rashid, S. N., Mohd. Yunus, M. M., Sarmidi, M. R.
Aims: Non-thermal atmospheric-pressure plasma (cold plasma), is described as a partly ionized gas. Cold plasma is a new method of medicine for killing the bacteria, treatment of cancer diseases, accelerates the healing of infectious ulcers, especially in infection caused by Meticillin-resistant Staphylococcus aureus (MRSA). This study aimed to investigate the impact of Non-thermal atmospheric-pressure plasma on MRSA S. aureus organism isolated from burn wound infection in vitro and in vivo.
Methodology and results: Five MRSA S. aureus strains were recovered in burn patients from Shahid Motahari Burns Hospital, Tehran, Iran. They confirmed by microbiology and biochemical tests. Antibiotic susceptibility testing was performed using Kirby Bauer Disk Diffusion Method with selected antibiotics. Then, the antibacterial impact of atmospheric non-thermal plasma on MRSA in vitro and in vivo at different times was assessed. After that, the tissue was randomly separated from the control and treated mice with plasma and transferred to the Histopathology Laboratory for further evaluation. Results of the inactivation of MRSA by non-thermal atmospheric plasma showed no bacterial growth. Also, the results of the impact of non-thermal helium plasma in vivo environment revealed that, in addition to healing in the animal wound, the burn wounds infection was healed and treated according to the histological results.
Conclusion, significance and impact of study: Our results confirmed the inactivation of MRSA S. aureus, healing of animal burn wound and complete treatment by non-thermal atmospheric plasma. It recommended that cold plasma can be used for the treatment of burn wounds infection due to the gentle on the human skin.
Keywords: Argon plasma, Staphylococcus aureus, burn
Aims: This study aimed to i) identify Pseudomonas savastanoi pv. savastanoi (Pss) as a causal agent of the olive knot on the basis of biochemical, pathogenicity and PCR technique ii) investigate in vitro bacterial resistance toward copper-based compounds and efficiency of some antibiotics on pathogen suppression.
Methodology and results: Biochemical, pathogenicity and molecular identification based on alkaline method for the DNA extraction were performed to identify possible causal agent of the olive knot. Copper resistance for Pss strains was evaluated by inoculation of bacterial suspensions into YPG medium, containing the cupric sulfate at 0, 100, 250 and 500 ppm. The efficiency of eight antibiotics on Pss strain was evaluated at different concentrations. Fifty-nine isolates caused typical knots at the site of inoculation with bacterial suspensions. All isolates have been identified as Pss using specific primers. No resistance to copper was detected with concentration of 500 ppm. In contrast, copper resistance was found during 48 h with lower concentration (100 or 250 ppm). The maximal inhibition of Pss 2102-4M was observed with the highest concentration (20 μg/mL) of the Aureomycin, Streptomycin and Novobiocin with inhibition diameters of 30, 24 and 10 mm, respectively. Whereas, Colchicine, Bacitracin, Cephalex, Ampicillin and Cycloserine have no inhibitory effect on the Pss 2102-4M strain.
Conclusion, significance and impact of study: The alkaline method for the DNA extraction from pure culture was reliable and rapid and can be recommended for molecular detection the causal agent of the olive knot. This is the first report determined copper resistance levels of Moroccan strains of Pss and in vitro evaluated for the susceptibility towards the antibiotics.
Keywords: olive knot, pathogenicity test, PCR, copper resistance, antibiotics
Molecular identification, in vitro copper resistance and antibiotics susceptibility of the causal agent of the olive knot disease in Morocco
- Abdelaaziz, B., Hanane, L., Mohamed, O., Imad, K., Khaoula, H., Abdellatif, B., Rachid, B., El hassan, A.
Aims: Diabetic patients with foot ulcer showed 150-fold increased risk of amputation, which is primarily caused by microbial infection. Silver ions are commonly incorporated into wound dressing to enhance the antimicrobial property. However, concerns have been expressed about the development of bacterial resistance to heavy metals. In this study, we extracted the nano-cellulose from medical cotton and reinforced with gelatin to develop a film for wound dressing.
Methodology and results: Garcinia mangostana L pericarp extract was incorporated into the nano-cellulose film as antimicrobial finishing. The efficacy of the developed nano-cellulose film was evaluated on diabetic wound microorganisms. We observed cellulose nano crystals with an average length of 133.71 nm under transmission electron microscope. The developed film showed gradual release of the extract over a period of 48 h and no burst effect was observed. The film exhibited significant inhibitory activity on 3 Gram positive bacteria, 3 Gram negative and all filamentous fungi tested. On Hohenstein challenge test, all test microorganisms showed significant growth reduction, with the treatment of the film. We also noticed that the antimicrobial activity of the film sustained even after 20 washes. Conclusion, significance and impact of study: Our results indicate that the G. mangostana L pericarp extract loaded nano-cellulose films exhibited significant inhibitory activity on diabetic wound microorganisms. The developed film can be potentially used to prevent foot ulcer infection among diabetic patients.
Keywords: G. mangostana, pericarp extract, antimicrobial activity, nanocellulose, gelatin
Aims: Erwinia psidii was first reported in 2017 to be the causal pathogen of papaya dieback disease (PDD) in Sabah, Malaysia. The present study aimed to isolate potential biocontrol agents against this pathogen.
Methodology and Results: Out of the 20 samples collected from Crocker Range of Sabah, 154 bacteria and 55 fungi isolates were isolated and screened for their antagonistic activity against E. psidii. The fungi and bacteria which gave the highest inhibition to E. psidii were identified using molecular technique as Alcaligenes faecalis and Lecanicillium sp., respectively. Both isolates were selected for extraction of their secondary metabolites to determine their bioactivity against E. psidii. Micro-well dilution method was used to determine minimum inhibitory concentration (MIC) for each microbes’ extract. GC-MS analysis was carried out to determine their secondary metabolites.
Conclusion, Significance and Impact of study: Lecanicillium sp. (Diethyl ether, chloroform and ethyl acetate) extracts and A. faecalis (Diethyl ether extract) showed positive inhibition against E. psidii. GC-MS analysis revealed that both A. faecalis and Lecanicillium sp. had secreted some secondary metabolites such as N-formylmaleamic acid, Oleamide and D-1-Piperideine-2-carboxylic acid that may relate to the growth inhibition. A. faecalis and Lecanicillium sp. are potential to be further investigated as biocontrol against E. psidii.
Keywords: Papaya dieback disease, Erwinia psidii, Alcaligenes faecalis, Lecanicillium sp.
Aims: Microencapsulation has been used to protect the viability of probiotics in harsh environments such as gastrointestinal conditions and food composition. The present study aimed to optimize the microencapsulation of Lactobacillus plantarum 299v (Lp299v) using co-extrusion by varying two parameters (calcium chloride (CaCl2) and oligofructose (FOS) concentrations) and storage stability of the beads produced in ambarella juice at refrigerated and room temperature. Methodology and results: Chitosan coated-alginate microcapsule prepared with 4.0% (w/v) FOS and 2.5% (w/v) CaCl2 showed highest microencapsulation efficiency (93%). The microcapsules were subjected to gastrointestinal treatment and storage test in ambarella juice. Both encapsulated Lp299v with and without FOS showed higher viabilities compared with free cells after incubated in simulated gastric juice (SGJ) and simulated intestinal juice (SIJ). After 5 h of incubation in SIJ, the viabilities of both encapsulated probiotic with and without FOS were more than 107 CFU/mL. The Lp299v were stored in ambarella juice under refrigerated (4 °C) and room temperature (25 °C) for 4 weeks. At 25 °C, all forms of Lp299v lost their viabilities after one week. On the other hand, at 4 °C, viable cells count of both encapsulated Lp299v with and without FOS were reported to be more than 107 CFU/mL after 4 weeks of storage. Conclusion, significance and impact of study: Microencapsulation with FOS was able to improve Lp299v’s viability during storage in low pH fruit juices compared to those without FOS. The microencapsulated probiotics could be applied in ambarella juice for the development of functional food.
Keywords: Ambarella, encapsulation, gastrointestinal condition, Lactobacillus plantarum, oligofructose
Aims: Paddy straw is known to have lignocellulosic materials such as cellulose and hemicellulose which can be readily converted into fermentable sugar for production of bioethanol via simultaneous saccharification and fermentation (SSF). In order to produce ethanol competently, the degradation of biomass by cellulase and highly ethanol-producing microorganism in fermentation process are necessarily needed. However, there is lacking in cellulose degrading organism in producing adequate amount of lignocellulosic enzyme. Therefore, the screening and selection for the best fungi to hydrolyze the lignocellulosic materials as well as forming consortium between two species of fungi has become the main focus.
Methodology and results: Thirteen strains of fast-growing fungi were tested qualitatively for cellulase (congo red staining) and polyphenol oxidase (Bavendamm test). All tested strains displayed lignocellulolytic fungi characteristics. The selection was narrowed down by quantitative assay on endoglucanase, exoglucanase, β-glucosidase and xylanase and the highest cellulases enzyme producer were T. asperellum B1581 (3.93 U/mL endoglucanase; 2.37 U/mL exoglucanase; 3.00 IU/mL β-glucosidase; 54.87 U/mL xylanase), followed by A. niger B2484 (5.60 U/mL endoglucanase; 1.08 U/mL exoglucanase; 1.57 IU/mL β-glucosidase; 56.85 U/mL xylanase). In compatibility test, both T. asperellum B1581 and A. niger B2484 were inoculated on the same petri dish for 4 days and the interaction showed by the two species was mutual intermingling.
Conclusions, significance and impact of study: Both Trichoderma asperellum B1581 and Aspergillus niger B2484 produced the highest cellulase enzyme. Since both strains can co-exist and produce enzymes that complete each other, a fungal consortium was suggested to increase the yield of sugars in saccharification process.
Keywords: Cellulose, hemicellulose, consortia, qualitative assay, quantitative assay
Aims: Candida albicans is a diploid yeast which interacts with the host in a complex nature involving several fungal virulence factors and host’s response. In this study, we investigated the different ABC genotypes of 26 clinical C. albicans isolates which is based on the presence of absence of transposable intron in the 25S rDNA, and the phenotypic expression of their virulence factors: phospholipase production, esterase production, haemolytic activities, biofilm formation, and white-opaque switching.
Methodology and Results: In this study, we investigated the ABC genotypes of 26 clinical C. albicans isolates, and the phenotypic expression of their virulence factors. The C. albicans isolates were tested for their in vitro abilities in exhibiting the following virulence factors: phospholipase, biofilm, esterase, hemolysin and phenotypic switching. Phospholipase activities and biofilm formation were detected in 57.7% and 65.38% of the isolates, respectively. All of the isolates showed phenotypic white-type colony, while none showed esterase and hemolytic activities. ABC genotyping revealed that 50% of the isolates were grouped under Genotype A, followed by Genotype C (42.3%), and B (7.69%).
Conclusion, Significance and Impact of study: This study provides information in regard to virulence potential and the ABC genotype of C. albicans from the Philippines.
Keywords: Phospholipase, biofilm, white-opaque switching, introns, ABC genotype
Aims: Up to date, there is limited heat-treated non-dairy probiotic food products in the market. Therefore, this study aims to develop a new functional cracker containing microencapsulated pumpkin-probiotics with acceptable sensory characteristics.
Methodology and results: The sample crackers (crackers with beads containing pumpkin and probiotic) have achieved a minimum required viable count of 6.26 ± 0.05 Log10 CFU/g and showed significantly (p<0.05) lower viability loss compared to control crackers (crackers with beads containing probiotic only). Sample crackers were perceived as acceptable (score 6.61) by 93 untrained panelists when tested using 9-point hedonic test. The ash content of sample pumpkin crackers was significantly higher (p<0.05) than the control. Both sample and control pumpkin crackers exhibit high level of total dietary fiber (>6%).
Conclusion, significance and impact of study: In summary, development of pumpkin crackers with microencapsulated L. acidophilus could be an alternative healthy option cracker for consumers. In addition, the results also suggested a new technique to deliver live culture in baked goods.
Keywords: Microencapsulation, pumpkin, Lactobacillus, crackers, probiotics
Aims: Oil palm (Elaeis guineensis) is the most productive and the highest yielding edible oil crop in the world and economic crop cultivated in Ghana. In September 2017, an outbreak of leaf spot caused by Pestalotiopsis sp, on oil palm seedlings was reported for the first time in Ghana. The disease incidence reached 85%, assuming an epidemic situation. This study is geared towards developing appropriate management strategies by identifying phytopathogenic fungi that caused leaf spot on oil palm seedlings.
Methodology and Results: Ten symptomatic leaves were picked per plot into sterilized plastic Ziploc bags and brought to laboratory. The leaves were washed under running tap water, cut into 1 cm pieces each, surface-sterilized with 10% sodium hypochlorite solution, rinsed three times in sterile distilled water and blotted on tissue paper (Gonthier et al., 2001). The sterilized samples were transferred aseptically onto potato dextrose agar (PDA) plate containing 0.5 mg/L of chloramphenicol and subcultured till pure culture was obtained. The result showed pure white colony which was concentric, cottony and velvety with slimy black dots of conidia mass on the tip of aerial mycelia. The fungus isolated and identified from the lesions on the leaf was Pestalotiopsis. sp and its pathogenicity confirmed.
Conclusion, significance and impact of study: the result from the study concludes that Pestalotiopsis. sp. could infect E. guineensis, which developed the same symptoms observed naturally in the field after inoculation. The fungus was identified based on morphological characteristics.
Keywords: Pestalotiopsis, Elaeis guineensis, leafspot, Pathogenicity, Carbendazim.