Displaying publications 1 - 20 of 23 in total

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  1. Fulltext Pathogenicity of a microsporidium isolate from the diamondback moth against Noctuid moths: characterization and implications for microbiological pest management
    Ghani IA, Dieng H, Abu Hassan ZA, Ramli N, Kermani N, Satho T, et al.
    PLoS One, 2013;8(12):e81642.
    PMID: 24349104 DOI: 10.1371/journal.pone.0081642
    Due to problems with chemical control, there is increasing interest in the use of microsporidia for control of lepidopteran pests. However, there have been few studies to evaluate the susceptibility of exotic species to microsporidia from indigenous Lepidoptera.
    Matched MeSH terms: Biological Control Agents
  2. Evaluation of a lytic bacteriophage, Φ st1, for biocontrol of Salmonella enterica serovar Typhimurium in chickens
    Wong CL, Sieo CC, Tan WS, Abdullah N, Hair-Bejo M, Abu J, et al.
    Int J Food Microbiol, 2014 Feb 17;172:92-101.
    PMID: 24361838 DOI: 10.1016/j.ijfoodmicro.2013.11.034
    In this study, a Salmonella Typhimurium lytic bacteriophage, Φ st1, which was isolated from chicken faecal material, was evaluated as a candidate for biocontrol of Salmonella in chickens. The morphology of Φ st1 showed strong resemblance to members of the Siphoviridae family. Φ st1 was observed to be a DNA phage with an estimated genome size of 121 kbp. It was found to be able to infect S. Typhimurium and S. Hadar, with a stronger lytic activity against the former. Subsequent characterisation of Φ st1 against S. Typhimurium showed that Φ st1 has a latent period of 40 min with an average burst size of 22 particles per infective centre. Approximately 86.1% of the phage adsorbed to the host cells within the initial 5 min of infection. At the optimum multiplicity of infection (MOI) (0.1), the highest reduction rate of S. Typhimurium (6.6 log₁₀ CFU/ml) and increment in phage titre (3.8 log₁₀ PFU/ml) was observed. Φ st1 produced adsorption rates of 88.4-92.2% at pH7-9 and demonstrated the highest bacteria reduction (6.6 log₁₀ CFU/ml) at pH9. Φ st1 also showed an insignificant different (P>0.05) reduction rate of host cells at 37 °C (6.4 log₁₀ CFU/ml) and 42 °C (6.0 log₁₀ CFU/ml). The in vivo study using Φ st1 showed that intracloacal inoculation of ~10¹² PFU/ml of the phage in the chickens challenged with ~10¹⁰ CFU/ml of S. Typhimurium was able to reduce (P<0.05) the S. Typhimurium more rapidly than the untreated group. The Salmonella count reduced to 2.9 log₁₀ CFU/ml within 6h of post-challenge and S. Typhimurium was not detected at and after 24h of post-challenge. Reduction of Salmonella count in visceral organs was also observed at 6h post-challenge. Approximately 1.6 log₁₀ FU/ml Φ st1 was found to persist in the caecal wall of the chicks at 72 h of post-challenge. The present study indicated that Φ st1 may serve as a potential biocontrol agent to reduce the Salmonella count in caecal content of chickens.
    Matched MeSH terms: Biological Control Agents*
  3. Isolation and identification of antagonistic bacteria from phylloplane of rice as biocontrol agents for sheath blight
    Akter S, Kadir J, Juraimi AS, Saud HM, Elmahdi S
    J Environ Biol, 2014 Nov;35(6):1095-100.
    PMID: 25522511
    A total of 325 bacteria were isolated from both healthy and sheath blight infected leaf samples of rice plants, collected from different places of Malaysia, following dilution technique. Sheath blight pathogen was isolated from infected samples by tissue plating method. Out of 325, 14 isolates were found to be antagonist against the pathogen in pre evaluation test. All the 14 isolates were morphologically characterized. Antagonistic activity of these isolates was further confirmed by adopting the standard dual culture and extracellular metabolite tests. The best isolates were selected, based on the results. In dual culture test, the selected bacterial isolates KMB25, TMB33, PMB38, UMB20 and BMB42 showed 68.44%, 60.89%, 60.22%, 50.00% and 48.22% fungal growth inhibition, respectively and in extracellular metabolite test these bacterial isolates exhibited 93.33%, 84.26%, 69.82%, 67.96% and 39.26% of the same, respectively. Biochemical tests of selected isolates were performed following standard procedure. These bacterial isolates were tentatively identified as fluorescent pseudomonas by morphological and biochemical characterization. The identities were further confirmed by Biolog microstation system as P. fluorescens (UMB20), P. aeruginosa (KMB25, TMB33 and PMB38) and P. asplenii (BMB42) with similarity index ranging from 0.517 to 0.697. The effective bacterial isolates obtained from the present study can be used in the management of soil borne fungal pathogen Rhizoctonia solani, causing sheath blight of rice.
    Matched MeSH terms: Biological Control Agents*
  4. In vitro and in vivo evaluation of streptomyces suppressions against anthracnose in chili caused by colletotrichum
    Shahbazi P, Md Yusoff Musa, Tan AGY, Farhat Ahmadi Avin, Teo AWF, Sabaratnam V
    Sains Malaysiana, 2014;43:697-705.
    The isolation of 66 streptomycetes from rhizosphere soil of chili plants was done for their inhibitory activities against three different dominant species of Colletotrichum namely C. acutatum, C. gloeosporioides and C. capsici. Twenty one streptomycetes strains were active against at least one of the Colletotrichum species. In addition, ten strains that inhibited the in vitro growth of Colletotrichum species showed chitinase activity. Strain P42, which displayed the highest inhibitory activity against all three anthracnose fungi species and high chitinase activity was tested as biological control agent in a greenhouse study. The strain successfully controlled chili anthracnose disease by significantly reducing the disease severity. Phylogenetic analysis of the 16S rRNA gene sequences showed that strain P42 belongs to the Streptomyces rochei clade. The results of the current study showed that rhizosphere-derived soil of chili plants is an important source of bioactive streptomycetes which are antagonistic against Colletotrichum.
    Matched MeSH terms: Biological Control Agents
  5. An in vitro study of the antifungal activity of Trichoderma virens 7b and a profile of its non-polar antifungal components released against Ganoderma boninense
    Angel LP, Yusof MT, Ismail IS, Ping BT, Mohamed Azni IN, Kamarudin NH, et al.
    J Microbiol, 2016 Nov;54(11):732-744.
    PMID: 27796927
    Ganoderma boninense is the causal agent of a devastating disease affecting oil palm in Southeast Asian countries. Basal stem rot (BSR) disease slowly rots the base of palms, which radically reduces productive lifespan of this lucrative crop. Previous reports have indicated the successful use of Trichoderma as biological control agent (BCA) against G. boninense and isolate T. virens 7b was selected based on its initial screening. This study attempts to decipher the mechanisms responsible for the inhibition of G. boninense by identifying and characterizing the chemical compounds as well as the physical mechanisms by T. virens 7b. Hexane extract of the isolate gave 62.60% ± 6.41 inhibition against G. boninense and observation under scanning electron microscope (SEM) detected severe mycelial deformation of the pathogen at the region of inhibition. Similar mycelia deformation of G. boninense was observed with a fungicide treatment, Benlate(®) indicating comparable fungicidal effect by T. virens 7b. Fraction 4 and 5 of hexane active fractions through preparative thin layer chromatography (P-TLC) was identified giving the best inhibition of the pathogen. These fractions comprised of ketones, alcohols, aldehydes, lactones, sesquiterpenes, monoterpenes, sulphides, and free fatty acids profiled through gas chromatography mass spectrometry detector (GC/MSD). A novel antifungal compound discovery of phenylethyl alcohol (PEA) by T. virens 7b is reported through this study. T. virens 7b also proved to be an active siderophore producer through chrome azurol S (CAS) agar assay. The study demonstrated the possible mechanisms involved and responsible in the successful inhibition of G. boninense.
    Matched MeSH terms: Biological Control Agents/isolation & purification; Biological Control Agents/pharmacology; Biological Control Agents/chemistry*
  6. The potential of endophytic bacteria as a biological control agent for ganoderma disease In oil palm
    Nur Rashyeda Ramli, Maizatul Suriza Mohamed, Idris Abu Seman, Madihah Ahmad Zairun, Nasyaruddin Mohamad
    Sains Malaysiana, 2016;45:401-409.
    This study was conducted to screen the endophytic bacteria as a biological control agent (BCA) against Ganoderma boninense. A total of 581 endophytic bacteria were successfully isolated from symptomless oil palm root tissues at Teluk Intan, Perak, Malaysia. Three endophytic bacteria, Pseudomonas aeruginosa GanoEB1, Burkholderia cepacia GanoEB2, and Pseudomonas syringae GanoEB3 were found to have a potential as BCA based on their percentage inhibition of radial growth (PIRG) in dual culture and culture filtrate tests. Two nursery trials were conducted to evaluate the capability of these bacteria to suppress Ganoderma disease in oil palm seedlings that were artificially infected with G. boninense using rubber wood block (RWB) sitting technique. The percentage of disease incidence (DI), severity of foliar symptoms (SFS) and dead seedlings were used as the assessment tools. As a result, DI and SFS have developed much slower in the seedlings that were pre-treated with bacteria compared to untreated seedlings. After 6 months of inoculation, Ganoderma disease incidence was reduced from 62-75% in the seedlings treated with P. aeruginosa GanoEB1, followed by B. cepacia GanoEB2 (31-59%) and P. syringae GanoEB3 (30-31%). Among these three endophytic bacteria, P. aeruginosa GanoEB1 was the most effective in controlling Ganoderma disease and the dead seedlings were in the range of 13.3-26.7%, followed by B. cepacia GanoEB2 (33.3% for both trials) and P. syringae GanoEB3 (33.3-40.0%) compared to untreated seedlings at 60% for both trials. A field study needs to be conducted to verify their effectiveness in controlling Ganoderma in oil palm.
    Matched MeSH terms: Biological Control Agents
  7. Spider (Araneae) predations on white-backed planthopper Sogatella furcifera in subtropical rice ecosystems, China
    Wang XQ, Wang GH, Zhu ZR, Tang QY, Hu Y, Qiao F, et al.
    Pest Manag Sci, 2017 Jun;73(6):1277-1286.
    PMID: 27739189 DOI: 10.1002/ps.4459
    BACKGROUND: Spiders are effective biological control agents in rice ecosystems, but the comparative study of predations among main spider species under field conditions has not been fully explored owing to a lack of practical methodology. In this study, more than 6000 spiders of dominant species were collected from subtropical rice ecosystems to compare their predations on Sogatella furcifera (Horváth) (white-backed planthopper, WBPH) using DNA-based gut content analysis.

    RESULTS: The positive rates for all spider taxa were closely related to prey densities, as well as their behaviors and niches. The relationships of positive rates to prey planthopper densities for Pardosa pseudoannulata (Böes. et Str.), Coleosoma octomaculata (Böes. et Str.), Tetragnatha maxillosa Thorell and Ummeliata insecticeps (Böes. et Str.) under field conditions could be described using saturated response curves. Quantitative comparisons of predations among the four spider species confirmed that P. pseudoannulata and C. octomaculata were more rapacious than U. insecticeps and T. maxillosa under field conditions. A comparison of ratio of spiders to WBPH and positive rates between fields revealed that biological control by spiders could be effectively integrated with variety resistance.

    CONCLUSION: Generalist spiders could follow up WBPH population timely, and assemblages of spiders coupled with variety resistance could effectively suppress WBPH population. © 2016 Society of Chemical Industry.

    Matched MeSH terms: Biological Control Agents
  8. Probiotics: From Isolation to Application
    Shokryazdan P, Faseleh Jahromi M, Liang JB, Ho YW
    J Am Coll Nutr, 2017 09 22;36(8):666-676.
    PMID: 28937854 DOI: 10.1080/07315724.2017.1337529
    Probiotics have become highly recognized as supplements for humans and animals because of their beneficial effects on health and well-being. The present review aims to provide an overview of different steps through which microbial strains become applicable probiotics in food and/or feed industries. Isolation of potential probiotic strains is the first step. Lactic acid bacteria are the most frequently used microorganisms as probiotics, which can be isolated from human, animal, plant, and environment. The next steps are identification of the isolates and characterization of them based on the main selection criteria for any potential probiotic microorganism, including resistance to gastric acidity and bile salt, adherence to mucus and/or intestinal epithelial cells and cell lines, and antimicrobial and antagonism activity against potentially pathogenic microbes. There are additional probiotic properties that may be considered for selection of probiotic strains with specific effects, such as cholesterol reduction ability, antioxidant activity, or cytotoxic effect against cancer cells. However, a potential probiotic does not need to fulfill all such selection criteria. As the last step, safety status of probiotics for humans is verified by taxonomy clarification, in vitro and in vivo tests, human trials, and genome sequencing.
    Matched MeSH terms: Biological Control Agents
  9. Global trends in research and commercialization of exogenous and endogenous RNAi technologies for crops
    Mat Jalaluddin NS, Othman RY, Harikrishna JA
    Crit Rev Biotechnol, 2018 Sep 09.
    PMID: 30198341 DOI: 10.1080/07388551.2018.1496064
    It has only been about 20 years since the first Nobel Prize-winning work on RNA interference (RNAi) in Caenorhabditis elegans was published in the journal Nature. Fast forward to today, and the use of RNA molecules as gene-silencing elements in crops has helped scientists to unveil possible solutions to the global problems of agricultural losses due to pests, viruses, pathogens, and to other abiotic and biotic stresses. The recent proliferation of publications suggests that the technology has gained significant attention and received ample funding support. In this article, an attempt has been made to visualize recent trends in Research & Development (R&D) investment in this field by analyzing top cited scholarly articles, patent trends, and commercialization activity. The publication and citation analysis identified that the development of RNAi-based crops conferring resistance against viruses, fungi, and pests are at the forefront of RNAi research and that Chinese and US institutions are the leaders in this field. The patent landscape analysis for RNAi technology over all aspects related to RNAi-derived crops provides an overview of patenting activity from a geographical, organizational, and legal perspective. Such an exercise is pivotal to industry players and public institutions aiming at creating intellectual property that is commercially appealing. An upswing in commercial interests in this technology in recent years is reflected by a consistent number of patent filings in US, European, and Chinese patent offices, with multinational giant firms as the most prolific patent filers. The expanding RNAi commercialization landscape is supported by a series of strategic partnerships, licensing agreements, and acquisitions created between agribusinesses, public research institutions, and startup companies. From key observations, we would like to highlight that such investments have very positive impacts on the development of RNAi technology. Nonetheless, the success of this technology is dependent on several factors, such as financial requirements, the complexity, and timeframe of the entire development process, as well as stringent regulations imposed by the relevant authorities. In most countries, RNAi-based transgenic crops are still considered as a genetically modified (GM) product, which necessitates the crops to undergo rigorous evaluation before approval is granted. Recent advancements in exogenous RNAi-derived biopesticides have provided a nontransgenic alternative to GM crops. However, challenges still remain in the form of technical hurdles and regulatory ambiguities surrounding this emerging technology. Its full potential remains to be realized.
    Matched MeSH terms: Biological Control Agents
  10. Optimization of metabolite extraction protocols for untargeted metabolite profiling of mycoparasitic scytalidium parasiticum using lc-tof-ms
    Lim CK, Nurul Fadhilah Marzuki, Goh YK, You KG, Kah JG, Rafidah Ahmad, et al.
    Sains Malaysiana, 2018;47:3061-3068.
    Basal stem rot disease of oil palm caused by Ganoderma boninense is one of the most devastating diseases in oil palm
    plantation resulting in low yield, loss of palm stands and shorter replanting cycle. To-date, there is no effective treatment
    for Ganoderma infected palms. Control measures, either chemical or cultural approaches, show varying degrees of
    effectiveness. The application of biological control agents which is environmental-friendly could be an attractive solution
    to overcome the problem. Earlier, we had isolated a mycoparasite, Scytalidium parasiticum, from the basidiomata of
    Ganoderma boninense. In vitro assay and nursery experiment showed that this fungus could suppress Ganoderma infection
    and reduce disease severity. However, metabolites which might contribute to the antagonistic or mycoparasitic effect
    remain unknown. In the current study, optimization of fungal sample processing, extraction, and analytical procedures
    were conducted to obtain metabolites from the maize substrate colonized by mycoparasitic ascomycetous Scytalidium
    parasiticum. This technique capable of producing sexual spores in sac-like organs. Untargeted metabolomics profiling
    was carried out by using Liquid Chromatography Time of Flight Mass Spectrometry (LC-ToF-MS). We found that
    S. parasiticum in both liquid- and solid-state cultivation gave higher metabolite when extracted with 60% methanol with
    1% formic acid in combination with homogenisation methods such as ultrasonication and grinding. The findings from
    this study are useful for optimisation of metabolite extraction from other fungi-Ganoderma-plant interactions.
    Matched MeSH terms: Biological Control Agents
  11. Interaction study of binary solvent systems ionic liquid and deep eutectic solvent with rotenone
    Zetty Shafiqa Othman, Nurul Huda Abd Karim, Saiful Irwan Zubairi, Nur Hasyareeda Hassan, Mamoru Koketsu
    Sains Malaysiana, 2018;47:1473-1482.
    [BMIM]OTf and alcohol-based DES combination with a selected organic solvent (acetone and acetonitrile) have
    been proven to efficiently extracting rotenone (isoflavonoid biopesticide) compound compared to individual organic
    solvents. Their efficiency builds up interest to study the solvent-solute interaction that occurs between both selected
    solvent systems with rotenone. The interaction study was analyzed using FTIR, 1D-NMR and 2D- NMR (NOESY, HMBC).
    Correlation portrayed by NOESY and HMBC of [BMIM]OTf - standard rotenone mixture predicted probable hydrogen
    bonding between the oxygen of rotenone with acidic proton C2-H of [BMIM]OTf. While for the alcohol-based DESrotenone
    mixture, the correlation shows probable interaction to occur between methyl and methoxy group rotenone
    with the hydroxyl group of 1,4-butanediol. In conclusion, potential hydrogen bonding that occurs between solvent
    and solute aid towards the solvent efficiency in extracting rotenone compound while emphasizing on the low cost and
    green mediated solvent systems.
    Matched MeSH terms: Biological Control Agents
  12. Proteomics as a tool for tapping potential of entomopathogens as microbial insecticides
    Harith Fadzilah N, Abdul-Ghani I, Hassan M
    Arch Insect Biochem Physiol, 2019 Jan;100(1):e21520.
    PMID: 30426561 DOI: 10.1002/arch.21520
    Biopesticides are collective pest control harnessing the knowledge of the target pest and its natural enemies that minimize the risks of synthetic pesticides. A subset of biopesticides; bioinsecticides, are specifically used in controlling insect pests. Entomopathogens (EPMs) are micro-organisms sought after as subject for bioinsecticide development. However, lack of understanding of EPM mechanism of toxicity and pathogenicity slowed the progress of bioinsecticide development. Proteomics is a useful tool in elucidating the interaction of entomopathogenic fungi, entomopathogenic bacteria, and entomopathogenic virus with their target host. Collectively, proteomics shed light onto insect host response to EPM infection, mechanism of action of EPM's toxic proteins and secondary metabolites besides characterizing secreted and membrane-bound proteins of EPM that more precisely describe relevant proteins for host recognition and mediating pathogenesis. However, proteomics requires optimized protein extraction methods to maximize the number of proteins for analysis and availability of organism's genome for a more precise protein identification.
    Matched MeSH terms: Biological Control Agents
  13. Effect of bioformulations on the biocontrol efficacy, microbial viability and storage stability of a consortium of biocontrol agents against Fusarium wilt of banana
    Wong CKF, Saidi NB, Vadamalai G, Teh CY, Zulperi D
    J Appl Microbiol, 2019 Aug;127(2):544-555.
    PMID: 31077517 DOI: 10.1111/jam.14310
    AIMS: This study sought to investigate the effect of bioformulation on the biocontrol efficacy, microbial viability and storage stability of a consortium of Pseudomonas aeruginosa DRB1 and Trichoderma harzianum CBF2 against Foc Tropical Race 4 (Foc-TR4).

    MATERIALS AND RESULTS: Four bioformulations consisting of dry (pesta granules, talc powder and alginate beads) and liquid formulations were evaluated for their ability to control Foc-TR4, sustain microbial populations after application and maintain microbial stability during storage. All tested bioformulations reduced disease severity (DS) by more than 43·00% with pesta granules producing the highest reduction in DS by 66·67% and the lowest area under the disease progress curve value (468·75) in a glasshouse trial. Microbial populations of DRB1 and CBF2 were abundant in the rhizosphere, rhizoplane and within the roots of bananas after pesta granules application as compared to talc powder, alginate beads and liquid formulations 84 days after inoculation (DAI). The stability of both microbial populations after 180 days of storage at 4°C was the greatest in the pesta granule formulation.

    CONCLUSION: The pesta granule formulation was a suitable carrier of biological control agents (BCA) without compromising biocontrol efficacy, microbial population and storage stability as compared to other bioformulations used in this study.

    SIGNIFICANCE AND IMPACT OF THE STUDY: Pesta granules could be utilized to formulate BCA consortia into biofertilizers. This formulation could be further investigated for possible applications under agricultural field settings.

    Matched MeSH terms: Biological Control Agents*
  14. Complete genome sequence of Oryctes rhinoceros nudivirus isolated from the coconut rhinoceros beetle in Solomon Islands
    Etebari K, Filipović I, Rašić G, Devine GJ, Tsatsia H, Furlong MJ
    Virus Res, 2020 03;278:197864.
    PMID: 31945420 DOI: 10.1016/j.virusres.2020.197864
    Oryctes rhinoceros nudivirus (OrNV) has been an effective biocontrol agent against the insect pest Oryctes rhinoceros (Coleoptera: Scarabaeidae) for decades, but there is evidence that resistance could be evolving in some host populations. We detected OrNV infection in O. rhinoceros from Solomon Islands and used Oxford Nanopore Technologies (ONT) long-read sequencing to determine the full length of the virus genomic sequence isolated from an individual belonging to a mitochondrial lineage (CRB-G) that was previously reported as resistant to OrNV. The complete circular genome of the virus consisted of 125,917 nucleotides, 1.698 bp shorter than the originally-described full genome sequence of Ma07 strain from Malaysia. We found 130 out of 139 previously annotated ORFs (seven contained interrupted/non-coding sequences, two were identified as duplicated versions of the existing genes), as well as a putatively inverted regions containing four genes. These results demonstrate the usefulness of a long-read sequencing technology for resolving potential structural variations when describing new virus isolates. While the Solomon Islands isolate exhibited 99.41 % nucleotide sequence identity with the originally described strain, we found several genes, including a core gene (vlf-1), that contained multiple amino acid insertions and/or deletions as putative polymorphisms of large effect. Our complete annotated genome sequence of a newly found isolate in Solomon Islands provides a valuable resource to help elucidate the mechanisms that compromise the efficacy of OrNV as a biocontrol agent against the coconut rhinoceros beetle.
    Matched MeSH terms: Biological Control Agents
  15. Fulltext Phytopathogenic organisms and mycotoxigenic fungi: Why do we control one and neglect the other? A biological control perspective in Malaysia
    Yazid SNE, Jinap S, Ismail SI, Magan N, Samsudin NIP
    Compr Rev Food Sci Food Saf, 2020 03;19(2):643-669.
    PMID: 33325175 DOI: 10.1111/1541-4337.12541
    In this review, we present the current information on development and applications of biological control against phytopathogenic organisms as well as mycotoxigenic fungi in Malaysia as part of the integrated pest management (IPM) programs in a collective effort to achieve food security. Although the biological control of phytopathogenic organisms of economically important crops is well established and widely practiced in Malaysia with considerable success, the same cannot be said for mycotoxigenic fungi. This is surprising because the year round hot and humid Malaysian tropical climate is very conducive for the colonization of mycotoxigenic fungi and the potential contamination with mycotoxins. This suggests that less focus has been made on the control of mycotoxigenic species in the genera Aspergillus, Fusarium, and Penicillium in Malaysia, despite the food security and health implications of exposure to the mycotoxins produced by these species. At present, there is limited research in Malaysia related to biological control of the key mycotoxins, especially aflatoxins, Fusarium-related mycotoxins, and ochratoxin A, in key food and feed chains. The expected threats of climate change, its impacts on both plant physiology and the proliferation of mycotoxigenic fungi, and the contamination of food and feed commodities with mycotoxins, including the discovery of masked mycotoxins, will pose significant new global challenges that will impact on mycotoxin management strategies in food and feed crops worldwide. Future research, especially in Malaysia, should urgently focus on these challenges to develop IPM strategies that include biological control for minimizing mycotoxins in economically important food and feed chains for the benefit of ensuring food safety and food security under climate change scenarios.
    Matched MeSH terms: Biological Control Agents
  16. Plant growth-promoting bacteria as potential bio-inoculants and biocontrol agents to promote black pepper plant cultivation
    Lau ET, Tani A, Khew CY, Chua YQ, Hwang SS
    Microbiol Res, 2020 Nov;240:126549.
    PMID: 32688172 DOI: 10.1016/j.micres.2020.126549
    Black pepper production in Malaysia was restricted by various diseases. Hazardous chemical products appear to be the best solution to control diseases in black pepper cultivation. However, persistence of chemical residues in peppercorns could affect the quality of exports and consumptions. Application of fertilizers is crucial to sustain pepper growth and high yield. But, continuous use of chemical fertilizers could affect the soil ecosystem and eventually restrict nutrient uptake by pepper roots. Therefore, we propose biological approaches as an alternative solution instead of chemical products to sustain pepper cultivation in Malaysia. In this study, we have isolated a total of seven indigenous rhizobacteria antagonistic to soil-borne Fusarium solani, the causal fungus of slow decline, the most serious debilitating disease of black pepper in Malaysia. The isolated bacteria were identified as Bacillus subtilis, Bacillus siamensis, Brevibacillus gelatini, Pseudomonas geniculata, Pseudomonas beteli, Burkholderia ubonensis and Burkholderia territorii. These bacteria were effective in production of antifungal siderophore with the amount of 53.4 %-73.5 % per 0.5 mL of cell-free supernatants. The bacteria also produced appreciable amount of chitinase with chitinolytic index was ranged from 1.19 to 1.76. The bacteria have shown phosphate solubilizing index within 1.61 to 2.01. They were also efficient in ACC deaminase (0.52 mM-0.62 mM) and ammonia (60.3 mM-75.3 mM) production. The isolated antagonists were efficacious in stimulation of black pepper plant growth and root development through IAA (10.5 μg/mL-42.6 μg/mL) secretion. In conclusion, the isolated rhizobacteria are potent to be developed not only as biocontrol agents to minimize the utilization of hazardous chemicals in black pepper disease management, but also developed as bio-fertilizers to improve black pepper plant growth due to their capabilities in plant growth-promotion.
    Matched MeSH terms: Biological Control Agents/pharmacology*
  17. Fulltext Wide area spray of bacterial larvicide, Bacillus thuringiensis israelensis strain AM65-52, integrated in the national vector control program impacts dengue transmission in an urban township in Sibu district, Sarawak, Malaysia
    Bohari R, Jin Hin C, Matusop A, Abdullah MR, Ney TG, Benjamin S, et al.
    PLoS One, 2020;15(4):e0230910.
    PMID: 32236146 DOI: 10.1371/journal.pone.0230910
    Several sites, Z-7L, Z-5 and Z-14, in Sibu district, Sarawak, Malaysia, experienced intense dengue transmission in 2014 that continued into 2015. A pilot study with Bacillus thuringiensis israelensis (Bti) to control Aedes aegypti (L.) and Ae. albopictus (Skuse) was evaluated in Z-7L, a densely populated site of 12 ha. Bti treatments were conducted weekly from epidemiology week (EW) 24/2015 for 4 weeks, followed by fortnight treatments for 2 months, in addition to the routine control activities. Bti was directly introduced into potable containers and the outdoor artificial and natural containers were treated via a wide area spray application method using a backpack mister. Aedes indices significantly reduced during the treatment and post treatment phases, compared to the control site, Z-5 (p<0.05). A 51 fold reduction in the incidence rate per 100,000 population (IR) was observed, with one case in 25 weeks (EW 29-52). In Z-5 and Z-14, control sites, a 6 fold reduction in the IR was observed from EW 29-52. However, almost every week there were dengue cases in Z-14 and until EW 44 in Z-5. In 2016, dengue cases resurfaced in Z-7L from EW 4. Intensive routine control activities were conducted, but the IR continued to escalate. The wide area Bti spray misting of the outdoor containers was then included from EW 27 on fortnight intervals. A 6 fold reduction in IR was observed in the Bti treatment phase (EW 32-52) with no successive weekly cases after EW 37. However, in the control sites, there were dengue cases throughout the year from EW 1-52, particularly in Z-14. We feel that the wide area Bti spray application method is an integral component in the control program, in conjunction with other control measures carried out, to suppress the vector population in outdoor cryptic containers and to interrupt the disease transmission.
    Matched MeSH terms: Biological Control Agents*
  18. Fulltext Lactobacillus plantarum strain HT-W104-B1: potential bacterium isolated from Malaysian fermented foods for control of the dermatophyte Trichophyton rubrum
    Danial AM, Medina A, Magan N
    World J Microbiol Biotechnol, 2021 Feb 24;37(4):57.
    PMID: 33625606 DOI: 10.1007/s11274-021-03020-7
    The objective was to screen and evaluate the anti-fungal activity of lactic acid bacteria (LABs) isolated from Malaysian fermented foods against two Trichophyton species. A total of 66 LAB strains were screened using dual culture assays. This showed that four LAB strains were very effective in inhibiting growth of T. rubrum but not T. interdigitale. More detailed studies with Lactobacillus plantarum strain HT-W104-B1 showed that the supernatant was mainly responsible for inhibiting the growth of T. rubrum. The minimum inhibitory concentration (MIC), inhibitory concentration, the 50% growth inhibition (IC50) and minimum fungicide concentration (MFC) were 20 mg/mL, 14 mg/mL and 30 mg/mL, respectively. A total of six metabolites were found in the supernatant, with the two major metabolites being L-lactic acid (19.1 mg/g cell dry weight (CDW)) and acetic acid (2.2 mg/g CDW). A comparative study on keratin agar media showed that the natural mixture in the supernatants predominantly contained L-lactic and acetic acid, and this significantly controlled the growth of T. rubrum. The pure two individual compounds were less effective. Potential exists for application of the natural mixture of compounds for the treatment of skin infection by T. rubrum.
    Matched MeSH terms: Biological Control Agents/pharmacology*
  19. Fulltext Interaction between Metarhizium anisopliae and Its Host, the Subterranean Termite Coptotermes curvignathus during the Infection Process
    Syazwan SA, Lee SY, Sajap AS, Lau WH, Omar D, Mohamed R
    Biology (Basel), 2021 Mar 25;10(4).
    PMID: 33806225 DOI: 10.3390/biology10040263
    Metarhizium anisopliae (Metchnikoff) Sorokin, a pathogenic fungus to insects, infects the subterranean termite, Coptotermes curvignathus Holmgren, a devastating pest of plantation trees in the tropics. Electron microscopy and proteomics were used to investigate the infection and developmental process of M. anisopliae in C. curvignathus. Fungal infection was initiated by germ tube penetration through the host's cuticle as observed at 6 h post-inoculation (PI), after which it elongated into the host's integumental tissue. The colonization process continued as seen from dissemination of blastospores in the hemocoel at 96 h PI. At this time point, the emergent mycelia had mummified the host and forty-eight hours later, new conidia were dispersed on the termites' body surface. Meanwhile, hyphal bodies were observed in abundance in the intercellular space in the host's body. The proteomes of the pathogen and host were isolated separately using inoculated termite samples withdrawn at each PI-time point and analyzed in two-dimensional electrophoresis (2-DE) gels. Proteins expressed in termites showed evidence of being related to cell regulation and the immune response, while those expressed in M. anisopliae, to transportation and fungal virulence. This study provides new information on the interaction between termites and its entomopathogen, with potential utilization for developing future biopesticide to control the termite population.
    Matched MeSH terms: Biological Control Agents
  20. Fulltext Current strategies and perspectives in detection and control of basal stem rot of oil palm
    Siddiqui Y, Surendran A, Paterson RRM, Ali A, Ahmad K
    Saudi J Biol Sci, 2021 May;28(5):2840-2849.
    PMID: 34012325 DOI: 10.1016/j.sjbs.2021.02.016
    The rapid expansion of oil palm (OP) has led to its emergence as a commodity of strategic global importance. Palm oil is used extensively in food and as a precursor for biodiesel. The oil generates export earnings and bolsters the economy of many countries, particularly Indonesia and Malaysia. However, oil palms are prone to basal stem rot (BSR) caused by Ganoderma boninense which is the most threatening disease of OP. The current control measures for BSR management including cultural practices, mechanical and chemical treatment have not proved satisfactory. Alternative control measures to overcome the G. boninense problem are focused on the use of biological control agents and many potential bioagents were identified with little proven practical application. Planting OP varieties resistant to G. boninense could provide the ideal long-term solution to basal stem rot. The total resistance of palms to G. boninense has not yet been reported, and few examples of partial resistances have been observed. Importantly, basidiospores are now recognized as the method by which the disease is spread, and control methods require to be revaluated because of this phenomenon. Many methods developed to prevent the spread of the disease effectively are only tested at nursery levels and are only reported in national journals inhibiting the development of useful techniques globally. The initial procedures employed by the fungus to infect the OP require consideration in terms of the physiology of the growth of the fungus and its possible control. This review assesses critically the progress that has been made in BSR development and management in OP.
    Matched MeSH terms: Biological Control Agents
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