1.Extracellular enzymatic activity of endophytic fungi isolated from spines of rattan palm (Calamus castaneus Griff.)
Nurul Farizah Azuddin ; Masratul Hawa Mohd ; Nik Fadzly Nik Rosely ; Asyraf Mansor ; Latiffah Zakaria
Malaysian Journal of Microbiology 2024;20(no.1):7-14
Aims:
Calamus castaneus is a non-climbing rattan plant widely distributed in tropical rainforests. The sharp spines of rattan palm harbour endophytic fungi, which may produce extracellular enzymes that contribute to various functions without harming the host plant. This study was aimed to evaluate the ability of fungal endophytes isolated from the C. castaneus spines to produce extracellular enzymes, including protease, pectinase, amylase, lipase and cellulase.
Methodology and results:
Thirty-four (34) endophytic fungal isolates were tested for their ability to produce extracellular enzymes using the agar plate method. Enzyme activity was measured using the enzyme index (EI) by measuring the halo (clear zone) on the agar medium. The EI value indicates the strength of the enzyme produced by the endophytes. Results demonstrated that all thirty-four fungal endophytes could produce at least one extracellular enzyme. Xylaria cubensis BR90 showed the highest protease activity of 5.73 EI. Muyocopron laterale (SM60) showed the highest pectinase activity of 2.74 EI. For lipase and cellulase activities, Cyphellophora guyanensis (BR71) produced 2.26 EI while Acremonium hennebertii (BR70) produced 1.97 EI, respectively.
Conclusion, significance and impact of study
Endophytic fungi from spines of C. castaneus were able to produce cellulase, pectinase, lipase, protease and amylase. The extracellular enzymes degraded different substrates, suggesting different types of interaction of the fungal endophytes with the host plant.
2.Antibiofilm activity of Nigrospora sphaerica CL-OP30 endophytic extract against Streptococcus mutans - the causative agent of dental caries
Nur A&rsquo ; fina Ahmad Mokhtar ; Darah Ibrahim ; Siti Shahara Zulfakar ; Latiffah Zakaria ; Kamarul Zaman Zarkasi
Malaysian Journal of Microbiology 2023;19(no.3):322-332
Aims:
The antibiofilm activity of endophytic fungus Nigrospora sphaerica CL-OP30 isolated from Swietenia macrophylla King was investigated.
Methodology and results:
The ability of the fungal endophytic crude extract to impede Streptococcus mutans biofilm formation was preliminarily screened with Congo red agar test. It was proven that S. mutans biofilm formation was hindered on the agar supplemented with the fungal endophytic crude extract. The antibiofilm activity of the fungal endophytic crude extract was evaluated using a microtiter plate method on both initially formed and preformed biofilm. Antibiofilm activity was recorded in a concentration-dependent pattern whereby higher concentrations reduced biofilm formation better than the lower concentrations of extract for both initially formed and preformed biofilm. The architecture of biofilm tested with fungal endophytic crude extract was also observed. Visualization under a light microscope and SEM revealed that the adherence of S. mutans biofilm treated with fungal endophytic crude extract was significantly
reduced in both initially formed and preformed biofilm. In addition, observation under SEM showed that the matrices surrounding the bacterial cells were disintegrated and bacterial cells in biofilm completely lost their original shape. The overall data demonstrated that the ethyl acetate N. spaherica CL-OP30 crude extract showed good antibiofilm activity.
Conclusion, significance and impact of study
The antibiofilm study suggested the potential of N. sphaerica CL-OP30 crude extract against S. mutans biofilm by disrupting the biofilm formation, the disintegration of matrices surrounding the biofilm and responsible for the formation of irregular cell shape. This extract may have a promising potential to be
developed as an antibiofilm agent.
3.Occurrence and identification of Penicillium and Talaromyces species from beach sand
Teh Li Yee ; Nurul Farizah Azuddin ; Masratul Hawa Mohd ; Latiffah Zakaria
Malaysian Journal of Microbiology 2022;18(6):652-664
Aims:
Penicillium and Talaromyces were among the species of microfungi that inhabit beach sand in Batu Ferringhi Beach, Penang Island, Malaysia. Previously, Talaromyces was described as the sexual stage of Penicillium, but both are now accepted as separate genera based on molecular phylogeny. The aim of the present study was to identify species of Penicillium and Talaromyces that are present in beach sand in Malaysia.
Methodology and results:
Species identities were confirmed according to similarities of the internal transcribed spacer regions and β-tubulin gene sequences and a phylogenetic analysis based on both regions/gene. Nine Penicillium spp. were identified as P. georgiense, P. chermesinum, P. pimiteouiense, P. citrinum, P. oxalicum, P. daleae, P. rolfsii and Penicillium sp. and the four Talaromyces spp. were T. siamense, T. atroroseus, T. minioluteus and T. fusiformis.
Conclusion, significance and impact of study
These findings showed that beach sand harboured a variety of Penicillium and Talaromyces species. The occurrence of Penicillium and Talaromyces in beach sands is associated with the organic matter in the sand, which provides suitable substrates and nutrient sources. Due to this, beach sand might harbour many potentially pathogenic or opportunistic species that may pose a health concern to immunocompromised individuals.
Penicillium
;
Talaromyces
;
Sand
4.Colletotrichum spp. associated with agricultural crops in Malaysia, causal pathogens and potential control methods
Malaysian Journal of Microbiology 2020;16(6):530-544
ABSTRACT
Colletotrichum is one of the most significant and common plant pathogens, infecting many economically important crops
worldwide. Colletotrichum is also one of the most studied fungal genera in Malaysia because it contains many species
that infect various types of agricultural crop including fruit, vegetable and industrial crops. Studies on Colletotrichum spp.
are mostly focused on the causal pathogens, the host range and disease management. Among the host crops, most
studies on Colletotrichum spp. have been conducted on infection in chilli (Capsicum spp.), which, in Malaysia, first arose
in the 1980s and still continues to be a problem to this day. Studies have also been conducted on Colletotrichum spp.
associated with anthracnose in fruit crops including dragon fruit, papaya, banana and mango. Disease management of
anthracnose pathogens postharvest has also been conducted to prolong the shelf life of these fruit crops. In this review,
Colletotrichum spp. associated with chilli and several fruit crops as well as their disease management are highlighted.
There have been many changes in Colletotrichum taxonomy and systematics in recent years, affecting the identification
of anthracnose pathogens reported in Malaysia. Colletotrichum species identified solely by morphology or solely via the
internal transcribed spacer (ITS) region should be referred to as sensu lato (in the broad sense) since many species
belong to species complexes. Species within a species complex are closely related, and most are cryptic species
particularly species in the C. gloeosporioides and C. acutatum complexes which are commonly associated with
agricultural crops in Malaysia. Due to the importance of Colletotrichum spp. as plant pathogens, up-to-date identification
methods should be used since accurate species identification of Colletotrichum is crucial for formulating suitable disease
management programmes as well as for plant quarantine and biosecurity purposes. This review provides the current
knowledge on the status of Colletotrichum spp. associated with agricultural crops in Malaysia and potential control
methods on different types of agricultural crops.
Colletotrichum--pathogenicity
5.Preliminary study on the effects of fusaric acid treated protocorm-like bodies of Dendrobium hybrid against Fusarium proliferatum and Fusarium oxysporum
Sangeetha Siva Sangu ; Nik Mohd Izham Mohamed Nor ; Latiffah Zakaria ; Azhar Mohamad ; Sreeramanan Subramaniam
Malaysian Journal of Microbiology 2019;15(2):152-158
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.
6.Aspergillus species from groundnuts (Arachis hypogaea) and mycotoxin production by toxigenic species
Amalina Kamaruddin ; Latiffah Zakaria
Malaysian Journal of Microbiology 2019;15(6):471-479
Aims:
Groundnut is an important food crop and is susceptible to contamination by Aspergillus. The present study was conducted to identify Aspergillus spp. from groundnuts as well as to detect mycotoxin production by toxigenic species.
Methodology and results:
Molecular identification using ITS region, β-tubulin and calmodulin genes identified six species, A. niger, A. tubingensis, A. flavus, A. aculeatus, A. sydowii and A. fumigatus. Phylogenetic tree of combined sequences showed the isolates from the same species were grouped with reference strains in the same clade, thus the species identity was confirmed. Detection of mycotoxin biosynthesis genes can give an indication of mycotoxin production. Two ochratoxin A genes, PKS15KS and PKS15C-MeT were detected in seven A. niger isolates but none of the isolates produced ochratoxin A when quantification was conducted using Ultra-High Performance Liquid Chromatography. Two aflatoxin B1 biosynthesis genes, Nor-1 (norsolorinic acid) and Ver-1 (Versicolorin) genes were detected in A. flavus but only KDH7 and KL27b isolates produced aflatoxin B1 with concentrations of 1.0 μg/g and 1.1 μg/g, respectively.
Conclusion, significance and impact of study
Various species of Aspergillus found on groundnuts may lead to potential mycotoxin contamination as toxigenic species were also recovered. The occurrence of Aspergillus spp. can reduce the quality of the legumes as well as reducing their shelf life.
7.Identification and Characterization of Macrophomina phaseolina Causing Leaf Blight on White Spider Lilies (Crinum asiaticum and Hymenocallis littoralis) in Malaysia
Abd Rahim HUDA-SHAKIRAH ; Yee Jia KEE ; Abu Bakar Mohd HAFIFI ; Nurul Nadiah MOHAMAD AZNI ; Latiffah ZAKARIA ; Masratul Hawa MOHD
Mycobiology 2019;47(4):408-414
Crinum asiaticum and Hymenocallis littoralis, commonly known as spider lilies are bulbous perennial and herbaceous plants that widely planted in Malaysia as ornamental. During 2015–2016, symptom of leaf blight was noticed on the hosts from several locations in Penang. The symptom appeared as irregular brown to reddish lesions surrounded by yellow halos. As the disease progressed, the infected leaves became blighted, dried, and fell off with the presence of black microsclerotia and pycnidia on the lesions parts. The present study was conducted to investigate the causal pathogen of leaf blight on C. asiaticum and H. littoralis. Based on morphological characteristics and DNA sequences of internal transcribed spacer (ITS) region and translation elongation factor 1-alpha (TEF1-α) gene, the causal pathogen was identified as Macrophomina phaseolina. Phylogenetic analysis of combined dataset of ITS and TEF1-α grouped the isolates studied with other isolates of M. phaseolina from GenBank. The grouping of the isolates was supported by 96% bootstrap value. Pathogenicity test proved the role of the fungus in causing leaf blight on both hosts.
8.The pathogen and control management of rice blast disease
Latiffah Zakaria ; Norsuha Misman
Malaysian Journal of Microbiology 2018;14(7):705-714
Abstracts
Outbreak of rice blast disease is a serious problem in all rice growing regions worldwide and is a threat to rice production. In Malaysia, the outbreak of rice blast is a recurrent problem where rice plant remain vulnerable to the disease. Nowadays, the generic name of rice blast pathogen is Pyricularia oryzae and Magnaporthe oryzae is the synonym. Rice pathogen infects mainly aerial parts of rice plant causing rotting and blast on the leaves, stems, peduncles, panicles and seeds leading to crop failure. Rice blast pathogen population is regarded as highly variable and consisted of multiple pathotypes which contribute to genetic diversity as well virulence diversity of the pathogen. The pathotypes can only be determined through pathogenicity test using a set of differential rice cultivars which generally differ by one or more resistance genes. Knowledge on the rice blast virulence and host resistant is important to manage the disease. Among the control methods, utilizing resistant cultivars is considered as the most effective approach to manage rice blast disease. Therefore, development of blast resistant cultivar becomes a priority.
9.Characterization of two xerophilic Aspergillus spp. from peanuts (Arachis hypogaea)
Nur Amalina KAMARUDIN ; Latiffah ZAKARIA
Malaysian Journal of Microbiology 2018;14(1):41-48
Aims: Xerophilic Aspergillus spp. promote the growth of toxigenic species. Since mycotoxins are toxic to human andanimal, identification of these species is important.Methodology and results: Two xerophilic species isolated from peanuts (Arachis hypogaea) were identified based onmorphological characteristics, molecular identification, and phylogenetic analysis using internal transcribed spacerregion, β-tubulin, and calmodulin sequences.Conclusion, significance and impact of study: The occurrence of A. chevalieri and A. amstelodami on peanutsprovides favorable growth conditions for less xerophilic Aspergillus as well as other spoilage-related fungal genera,particularly mycotoxin-producing species that could lead to mycotoxin contamination. The occurrence of A. chevalieriand A. amstelodami on peanuts might also reduce shelf life and affect the quality of the kernels. To our knowledge, thisis the first report of the occurrence of A. chevalieri and A. amstelodami on a food product in Malaysia, and the finding ofthis study contributes to the repertoire of Aspergillus species that are associated with food products.
10.Occurrence of microfungi on several dried fruits
Latiffah Zakaria ; Lim Choong Yee ; Teh Li Yee
Malaysian Journal of Microbiology 2015;11(3):313-316
Aims: Dried fruits may harbour a variety of fungi especially those that can grow in low water activity conditions.
Knowledge on the occurrence of fungi on dried fruits is an important step to predict the possibility of mycotoxin
contamination, thus the present study was conducted to determine the occurrence of fungi on dates, figs, kiwi and
raisins.
Methodology and results: Based on morphological characteristics, six genera of fungi comprising eight species,
Aspergillus niger, A. flavus, Penicillium corylophilum, P. glabrum, Chaetomium globosum, Fusarium sacchari,
Acremonium strictum and Mycelia sterilia were identified. Three most commonly species isolated were A. niger (19
isolates), P. corylophilum (seven isolates) and A. flavus (five isolates). The less common species were C. globosum
(three isolates), Mycelia sterilia (three isolates), A. strictum (one isolate) and P. glabrum (one isolate).
Conclusion, significance and impact of study: Common mycotoxin producer are the fungi from the genera
Aspergillus, Penicillium and Fusarium. The occurrence of toxigenic fungi on dates, figs, kiwi and raisins suggested that
some of these fungi may be an important source of mycotoxin contamination.
Fungi


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