Displaying publications 1 - 20 of 63 in total

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  1. Fulltext Important zoonotic intestinal protozoan parasites in Asia
    Mak JW
    Trop Biomed, 2004 Dec;21(2):39-50.
    PMID: 16493397
    Intestinal protozoa are increasingly being studied because of their association with acute and chronic diarrhoea in immunocompromised as well as immunocompetent patients. Various community outbreaks due to contamination of water or food with these protozoa have further highlighted their importance in public health. Among these important pathogens are Giardia duodenalis, Entamoeba histolytica, Cryptosporidium parvum, Cyclospora cayetanensis, Isospora belli, and microsporidia. Except for the cyst-forming G. duodenalis and E. histolytica, the others are intracellular and form spores which are passed out with the faeces. These organisms are also found in various animals and birds and zoonotic transmission is thought to occur. These infections are distributed worldwide, with a higher prevalence in developing compared to developed countries. However, the relative importance of zoonotic infections especially in developing countries has not been studied in detail. The prevalence rates are generally higher in immunodeficient compared to immunocompetent patients. Higher prevalence rates are also seen in rural compared to urban communities. Most studies on prevalence have been carried out in developed countries where the laboratory and other health infrastructure are more accessible than those in developing countries. This relative inadequacy of laboratory diagnosis can affect accurate estimates of the prevalence of these infections in developing countries. However, reports of these infections in travellers and workers returning from developing countries can provide some indication of the extent of these problems. Most studies on prevalence of amoebiasis in developing countries were based on morphological identification of the parasite in faecal smears. As the pathogenic E. histolytica is morphologically indistinguishable from that of non-pathogenic E. dispar, estimates of amoebiasis may not be accurate. The epidemiology of human microsporidia infections is not completely understood. Two species, Enterocytozoon bieneusi and Encephalitozoon intestinalis, are associated with gastrointestinal disease in humans and it is believed that human to human as well as animal to human infections occur. However, the importance of zoonotic infections has not been fully characterised. G. duodenalis cysts, microsporidia and Cryptosporidium oocysts have been detected in various ground water resources, but their role in community outbreaks and maintenance of the infection has not been fully characterised. The taxonomic classification and pathogenic potential of B. hominis are still controversial. While considered by many as yeast, fungi or protozoon, recent sequence analysis of the complete SSUrRNA gene has placed it within an informal group, the stramenopiles. This review covers recent published data on these zoonotic infections and examines their public health importance in Asian countries.
    Matched MeSH terms: Yeast, Dried
  2. Culture and molecular identification of fungal contaminants in edible bird nests
    Chen JX, Wong SF, Lim PK, Mak JW
    Food Addit Contam Part A Chem Anal Control Expo Risk Assess, 2015;32(12):2138-47.
    PMID: 26429550 DOI: 10.1080/19440049.2015.1101494
    Widespread food poisoning due to microbial contamination has been a major concern for the food industry, consumers and governing authorities. This study is designed to determine the levels of fungal contamination in edible bird nests (EBNs) using culture and molecular techniques. Raw EBNs were collected from five house farms, and commercial EBNs were purchased from five Chinese traditional medicine shops (companies A-E) in Peninsular Malaysia. The fungal contents in the raw and commercial EBNs, and boiled and unboiled EBNs were determined. Culturable fungi were isolated and identified. In this study, the use of these methods revealed that all EBNs had fungal colony-forming units (CFUs) that exceeded the limit set by Standards and Industrial Research Institute of Malaysia (SIRIM) for yeast and moulds in EBNs. There was a significant difference (p < 0.05) in the number of types of fungi isolated from raw and commercial EBNs, but no significant difference in the reduction of the number of types of fungi after boiling the EBNs (p > 0.05). The types of fungi isolated from the unboiled raw EBNs were mainly soil, plant and environmental fungi, while the types of fungi isolated from the boiled raw EBNs, unboiled and boiled commercial EBNs were mainly environmental fungi. Aspergillus sp., Candida sp., Cladosporium sp., Neurospora sp. and Penicillum sp. were the most common fungi isolated from the unboiled and boiled raw and commercial EBNs. Some of these fungi are mycotoxin producers and cause opportunistic infections in humans. Further studies to determine the mycotoxin levels and methods to prevent or remove these contaminations from EBNs for safe consumption are necessary. The establishment and implementation of stringent regulations for the standards of EBNs should be regularly updated and monitored to improve the quality of the EBNs and consumer safety.
    Matched MeSH terms: Yeast, Dried
  3. Fulltext Phylogenetic and Transcripts Profiling of Glucose Sensing Related Genes in Candida glabrata
    Ng TS, Mohd Desa MN, Sandai D, Chong PP, Than LT
    Jundishapur J Microbiol, 2015 Nov;8(11):e25177.
    PMID: 26855740 DOI: 10.5812/jjm.25177
    BACKGROUND: The sensing mechanism of glucose in Saccharomyces cerevisiae is well studied. However, such information is scarcely found in other yeast species such as Candida glabrata.

    OBJECTIVES: This study aimed to identify the glucose sensing pathway related genes of C. glabrata and to analyze the regulation pattern of these genes in response to different surrounding glucose concentrations through the quantitative real time polymerase chain reaction (qRT-PCR).

    MATERIALS AND METHODS: Phylogenetic analysis was carried out on predicted amino acid sequences of C. glabrata and S. cerevisiae to compare their degree of similarity. In addition, the growth of C. glabrata in response to different amounts of glucose (0%, 0.01%, 0.1%, 1% and 2%) was evaluated via the spot dilution assay on prepared agar medium. Besides, the SNF3 and RGT2, which act as putative glucose sensors, and the RGT1 and MIG1, which act as putative transcriptional regulators and selected downstream hexose transporters (HXTs), were analysed through qRT-PCR analysis for the gene expression level under different glucose concentrations.

    RESULTS: Comparative analysis of predicted amino acids in the phylogenetic tree showed high similarity between C. glabrata and S cerevisiae. Besides, C. glabrata demonstrated the capability to grow in glucose levels as low as 0.01% in the spot dilution assay. In qRT-PCR analysis, differential expressions were observed in selected genes when C. glabrata was subjected to different glucose concentrations.

    CONCLUSIONS: The constructed phylogenetic tree suggests the close evolutionary relationship between C. glabrata and S. cerevisiae. The capability of C. glabrata to grow in extremely low glucose environments and the differential expression of selected glucose-sensing related genes suggested the possible role of these genes in modulating the growth of C. glabrata in response to different glucose concentrations. This study helps deepen our understanding of the glucose sensing mechanism in C. glabrata and serves to provide fundamental data that may assist in unveiling this mechanism as a potential drug target.

    Matched MeSH terms: Yeast, Dried
  4. Fulltext Pre-grafting histological studies of skin grafts cryopreserved in α helix antarctic yeast oriented antifreeze peptide (Afp1m)
    Khan MS, Ibrahim SM, Adamu AA, Rahman MBA, Bakar MZA, Noordin MM, et al.
    Cryobiology, 2020 02 01;92:26-33.
    PMID: 31580830 DOI: 10.1016/j.cryobiol.2019.09.012
    A number of living creatures in the Antarctic region have developed characteristic adaptation of cold weather by producing antifreeze proteins (AFP). Antifreeze peptide (Afp1m) fragment have been designed in the sequence of strings from native proteins. The objectives of this study were to assess the properties of Afp1m to cryopreserve skin graft at the temperature of -10 °C and -20 °C and to assess sub-zero injuries in Afp1m cryopreserved skin graft using light microscopic techniques. In the present study, a process was developed to cryopreserve Sprague-Dawley (SD) rat skin grafts with antifreeze peptide, Afp1m, α-helix peptide fragment derived from Glaciozyma antractica yeast. Its viability assessed by different microscopic techniques. This study also described the damages caused by subzero temperatures (-10 and -20 °C) on tissue cryopreserved in different concentrations of Afp1m (0.5, 1, 2, 5 and 10 mg/mL) for 72 h. Histological scores of epidermis, dermis and hypodermis of cryopreserved skin grafts showed highly significant difference (p 
    Matched MeSH terms: Yeast, Dried
  5. Structure and function of the vacuolar Ccc1/VIT1 family of iron transporters and its regulation in fungi
    Sorribes-Dauden R, Peris D, Martínez-Pastor MT, Puig S
    Comput Struct Biotechnol J, 2020;18:3712-3722.
    PMID: 33304466 DOI: 10.1016/j.csbj.2020.10.044
    Iron is an essential micronutrient for most living beings since it participates as a redox active cofactor in many biological processes including cellular respiration, lipid biosynthesis, DNA replication and repair, and ribosome biogenesis and recycling. However, when present in excess, iron can participate in Fenton reactions and generate reactive oxygen species that damage cells at the level of proteins, lipids and nucleic acids. Organisms have developed different molecular strategies to protect themselves against the harmful effects of high concentrations of iron. In the case of fungi and plants, detoxification mainly occurs by importing cytosolic iron into the vacuole through the Ccc1/VIT1 iron transporter. New sequenced genomes and bioinformatic tools are facilitating the functional characterization, evolution and ecological relevance of metabolic pathways and homeostatic networks across the Tree of Life. Sequence analysis shows that Ccc1/VIT1 homologs are widely distributed among organisms with the exception of animals. The recent elucidation of the crystal structure of a Ccc1/VIT1 plant ortholog has enabled the identification of both conserved and species-specific motifs required for its metal transport mechanism. Moreover, recent studies in the yeast Saccharomyces cerevisiae have also revealed that multiple transcription factors including Yap5 and Msn2/Msn4 contribute to the expression of CCC1 in high-iron conditions. Interestingly, Malaysian S. cerevisiae strains express a partially functional Ccc1 protein that renders them sensitive to iron. Different regulatory mechanisms have been described for non-Saccharomycetaceae Ccc1 homologs. The characterization of Ccc1/VIT1 proteins is of high interest in the development of biofortified crops and the protection against microbial-derived diseases.
    Matched MeSH terms: Yeast, Dried
  6. Fulltext Antifreeze Proteins and Their Practical Utilization in Industry, Medicine, and Agriculture
    Eskandari A, Leow TC, Rahman MBA, Oslan SN
    Biomolecules, 2020 12 09;10(12).
    PMID: 33317024 DOI: 10.3390/biom10121649
    Antifreeze proteins (AFPs) are specific proteins, glycopeptides, and peptides made by different organisms to allow cells to survive in sub-zero conditions. AFPs function by reducing the water's freezing point and avoiding ice crystals' growth in the frozen stage. Their capability in modifying ice growth leads to the stabilization of ice crystals within a given temperature range and the inhibition of ice recrystallization that decreases the drip loss during thawing. This review presents the potential applications of AFPs from different sources and types. AFPs can be found in diverse sources such as fish, yeast, plants, bacteria, and insects. Various sources reveal different α-helices and β-sheets structures. Recently, analysis of AFPs has been conducted through bioinformatics tools to analyze their functions within proper time. AFPs can be used widely in various aspects of application and have significant industrial functions, encompassing the enhancement of foods' freezing and liquefying properties, protection of frost plants, enhancement of ice cream's texture, cryosurgery, and cryopreservation of cells and tissues. In conclusion, these applications and physical properties of AFPs can be further explored to meet other industrial players. Designing the peptide-based AFP can also be done to subsequently improve its function.
    Matched MeSH terms: Yeast, Dried
  7. Fulltext Saprophytic yeasts: effective biocontrol agents against Aspergillus flavus
    Afsah-Hejri, L.
    International Food Research Journal, 2013;20(6):3403-3409.
    MyJurnal
    Aflatoxins are carcinogenic, mutagenic and teratogenic fungal toxins predominantly produced by Aspergillus flavus (A. flavus) and Aspergillus parasiticus (A. parasiticus). Members of the Aspergillus family are wound-invading pathogens that can infect pistachio trees and nuts. The pistachio nut is a favorite tree nut worldwide, and more than half of the world’s pistachio production is from Iran. Pistachio nuts can easily be infected with Aspergillus spp. due to early splitting or due to animal, insect or physical damage. Any established infection of Aspergillus under high relative humidity and temperature results in the production and rapid accumulation of aflatoxins in pistachio nuts. It is impractical to remove aflatoxins from pistachio nuts after they are produced. Some microorganisms (such as saprophytic yeasts) have been reported to have an antagonistic effect against Aspergillus spp. This study aimed to isolate saprophytic yeasts from pistachio fruits and leaves and investigate their biocontrol activities against a toxigenic strain of Aspergillus flavus (A. flavus). Saprophytic yeasts were identified based on their morphological properties and biochemical tests. In total, 24 yeast isolates were obtained from pistachio fruits and leaves, and their antagonistic effect on A. flavus (PTCC 5006) was investigated. Five saprophytic yeast isolates, displaying the highest biocontrol activities against A. flavus (PTCC 5006), were identified as Pseudozyma fusiformata, Cryptococcus albidus, Rhodotorula fragaria, Cryptococcus hungaricus and Rhodotorula hinula. The biocontrol activities of these yeast isolates were evaluated by their inhibitory effects on sporulation, colony expansion, biomass production and prevention of aflatoxin B1 (AFB1) production. Pseudozyma fusiformata was the most effective yeast isolate in terms of spore reduction (84.6%) and inhibition of AFB1 production (89.1%). Cryptococcus albidus produced the maximum reduction in fungal dry weight (77.9%). Based on these results, isolated saprophytic yeasts from pistachio fruits and leaves can be used as effective biocontrol agents against the growth of Aspergillus and aflatoxin production.
    Matched MeSH terms: Yeast, Dried
  8. Fulltext Potential of fermented papaya beverage in the prevention of foodborne illness incidence
    Koh, S.P., Aziz, N., Sharifudin, S.A., Abdullah, R., Hamid, N.S.A., Sarip, J.
    Food Research, 2017;1(4):109-113.
    MyJurnal
    Foodborne illness is recognized as an emerging infectious disease. The incidence of foodborne
    infections is common and the majority cases are undiagnosed or unreported. Apart from some
    diarrhea or minor gastrointestinal problem, some foodborne pathogenic microbes may cause
    death, particularly to those people with weakened immune system. In this study, we have
    developed a new fermented papaya beverage using symbiotic culture of yeast and acetic acid
    bacteria under controlled biofermentation process. An in-vitro assessment of fermented papaya
    beverage against few foodborne pathogenic microorganism was conducted to determine
    its minimum bactericidal concentration (MBC>99). Three types of foodborne pathogen:
    Escherichia coli O157, Salmonella enterica serovar Typhimurium ATCC 53648, Salmonella
    enterica serovar Enteritidis (isolated from infectious chicken) were selected. From minimum
    bactericidal concentration (MBC>99) assay, both fermented papaya pulp and leaves beverages
    have shown 100% killing rate against three selected foodborne pathogenic microbes. Inversely,
    non-fermented papaya pulp and leaves beverages indicated no inhibition at all. In fact, further
    dilution of fermented papaya pulp and leaves beverages demonstrated different degree of
    MBC>99 and brix value, but the pH value remained less than 3.5. These findings indicated
    the combination of soluble solid compounds presents in both fermented papaya beverage and
    product acidity play an important role in the inhibition of pathogenic microorganisms. The
    preliminary promising results of this work have shown that the great potential of fermented
    papaya beverages as a preventive measure to reduce the incidence of foodborne illness.
    Matched MeSH terms: Yeast, Dried
  9. Responses of different strains of Saccharomyces cerevisiae to osmotic stress
    Noorhisham Tan Kofli, Nagahisa K, Shioya S, Shimizu H
    Sains Malaysiana, 2006;35:9-15.
    During fermentation cells are subjected to various kinds of stress. One of the stresses concerned is high osmotic environment, which cells need to encounter in order to continue growing. To understand how cells adapt to this stress condition, information from genome, proteome and metabolome levels are crucial. In yeast cells, it was report that they produce glycerol to avoid depletion of water in the cell that could lead to cell shrinkage and eventually death. Thus, investigation of physiological responses were executed by shake flask method using three different Saccharomyces cerevisiae strains namely s288c, IFO2347 and FY834 which were grown in yeast potato dextrose (YPD) medium under the treatment of sodium chloride (NaCl) and sorbitol at 1M concentration to create the osmotic condition. These agents were added into the medium after 5 hours of fermentation when the cells reached exponential phase and carbon source is still available. The results proved that addition of both NaCl and sorbitol created the osmotic condition during growth resulted in higher accumulation of glycerol and trehalose when compared to the control in all strains. Among these strains, production of glycerol (g glycerol/g cell dry weight) was found highest in IFO2347, followed by s288c and FY834.
    Matched MeSH terms: Yeast, Dried
  10. Antimicrobial activity of fungal endophytes from vaccinium dunalianum var. Urophyllum
    Xin Tong, Xiao-ye Shen, Cheng-lin Hou
    Sains Malaysiana, 2018;47:1685-1692.
    Fungi associated with Vaccinium species play important roles in plant growth and disease control, especially in the final
    blueberry production. Vaccinium dunalianum var. urophyllum (Ericaceae) is a well-known medicinal plant in Southern
    China used to treat inflammation and microbial infections. The endophytic fungi from these plants are therefore anticipated
    as potential new sources of antimicrobials. In this report, the inhibitory effects of endophytes against clinical bacteria
    and yeast were comprehensively screened and 11 isolates indicated high bioactivity by the agar diffusion method. The
    corresponding crude extracts of these fungi under submerged fermentation also demonstrated distinct differences and
    n-butyl alcohol displayed the lowest extraction efficiency among the extracts. The ethyl acetate and dichloromethane
    extracts of filtrates from the Colletotrichum sp. VD001, Epicoccum nigrum VD021 and E. nigrum VD022 strains
    displayed good properties against pathogenic microorganisms according to disc diffusion assays and minimal inhibitory
    concentration (MIC). This study is the first indicating that cultivable endophytic fungi associated with blueberry plants
    produce potential compounds against clinical pathogens.
    Matched MeSH terms: Yeast, Dried
  11. Structural insight into tanapoxvirus mediated inhibition of apoptosis
    Suraweera CD, Anasir MI, Chugh S, Javorsky A, Impey RE, Hasan Zadeh M, et al.
    FEBS J, 2020 May 15.
    PMID: 32412687 DOI: 10.1111/febs.15365
    Premature programmed cell death or apoptosis of cells is a strategy utilized by multicellular organisms to counter microbial threats. Tanapoxvirus (TANV) is a large double-stranded DNA virus belonging to the poxviridae that causes mild Monkeypox-like infections in humans and primates. TANV encodes for a putative apoptosis inhibitory protein 16L. We show that TANV16L is able to bind to a range of peptides spanning the BH3 motif of human pro-apoptotic Bcl-2 proteins, and is able to counter growth arrest of yeast induced by human Bak and Bax. We then determined the crystal structures of TANV16L bound to three identified interactors, Bax, Bim and Puma BH3. TANV16L adopts a globular Bcl-2 fold comprising 7 a-helices, and utilizes the canonical Bcl-2 binding groove to engage pro-apoptotic host cell Bcl-2 proteins. Unexpectedly, TANV16L is able to adopt both a monomeric as well as a domain-swapped dimeric topology where the a1 helix from one protomer is swapped into a neighbouring unit. Despite adopting two different oligomeric forms, the canonical ligand binding groove in TANV16L remains unchanged from monomer to domain-swapped dimer. Our results provide a structural and mechanistic basis for tanapoxvirus mediated inhibition of host cell apoptosis, and reveal the capacity of Bcl-2 proteins to adopt differential oligomeric states whilst maintaining the canonical ligand binding groove in an unchanged state.
    Matched MeSH terms: Yeast, Dried
  12. Phomopsidione-Loaded Chitosan Polyethylene Glycol (PEG) Nanocomposite Dressing for Pressure Ulcers
    Chin IBI, Yenn TW, Ring LC, Lazim Y, Tan WN, Rashid SA, et al.
    J Pharm Sci, 2020 09;109(9):2884-2890.
    PMID: 32534882 DOI: 10.1016/j.xphs.2020.06.005
    Pressure ulcers are commonly associated with microbial infections on the wounds which require an effective wound dressing for treatment. Thus far, the available silver dressing has shown tremendous result, however, it may cause argyria and complicate the internal organ function. Hence, our study aims to develop and characterize phomopsidione-loaded chitosan-polyethylene glycol nanocomposite hydrogel (C/PEG/Ph) as an antimicrobial dressing. Physically, the C/PEG/Ph hydrogel demonstrated a uniform light blue color, soft, flexible, and elastic, with no aggregation form. The evaluation via Fourier Transform Infrared (FTIR) exposed the C/PEG/Ph hydrogel has a notable shift towards lower frequency at 1600 and 1554 cm-1. For drug release test, the phomopsidione attained plateau at 24 h, with a total release of 67.9 ± 6.4% from the C/PEG/Ph hydrogel. There was a null burst release effect discovered throughout the experimental period. The C/PEG/Ph hydrogel showed significant results against all 4 Gram-negative bacteria and 1 yeast, with 99.99-100% reduction of microbial growth. The findings revealed that the C/PEG/Ph hydrogel can potentially act as an antimicrobial dressing for pressure ulcers.
    Matched MeSH terms: Yeast, Dried
  13. Screening and identification of host proteins interacting with Toxoplasma gondii SAG2 by yeast two-hybrid assay
    Lai MY, Lau YL
    Parasit Vectors, 2017 Oct 02;10(1):456.
    PMID: 28969712 DOI: 10.1186/s13071-017-2387-y
    BACKGROUND: The identification of receptors or binding partners of Toxoplasma gondii from humans is an essential activity. Many proteins involved in T. gondii invasion have been characterized, and their contribution for parasite entry has been proposed. However, their molecular interactions remain unclear.

    RESULTS: Yeast two-hybrid (Y2H) experiment was used to identify the binding partners of surface antigens of T. gondii by using SAG2 as bait. Colony PCR was performed and positive clones were sent for sequencing to confirm their identity. The yeast plasmids for true positive clones were rescued by transformation into E. coli TOP 10F' cells. The interplay between bait and prey was confirmed by β-galactosidase assay and co-immunoprecipitation experiment. We detected 20 clones interacting with SAG2 based on a series of the selection procedures. Following the autoactivation and toxicity tests, SAG2 was proven to be a suitable candidate as a bait. Thirteen clones were further examined by small scale Y2H experiment. The results indicated that a strong interaction existed between Homo sapiens zinc finger protein and SAG2, which could activate the expressions of the reporter genes in diploid yeast. Co-immunoprecipitation experiment result indicated the binding between this prey and SAG2 protein was significant (Mann-Whitney U-test: Z = -1.964, P = 0.05).

    CONCLUSIONS: Homo sapiens zinc finger protein was found to interact with SAG2. To improve the understanding of this prey protein's function, advanced investigations need to be carried out.

    Matched MeSH terms: Yeast, Dried
  14. Evaluating the Potential of Oleaginous Yeasts as Feedstock for Biodiesel Production
    Mukhtar H, Suliman SM, Shabbir A, Mumtaz MW, Rashid U, Rahimuddin SA
    Protein Pept Lett, 2018;25(2):195-201.
    PMID: 29359654 DOI: 10.2174/0929866525666180122112805
    BACKGROUND: Lipid-producing microorganisms, said to be oleaginous have been recognized since several years. We had investigated the effects of medium components and culturing situations on cell growth and lipid accumulation of oleaginous yeasts which were analytically examined so as to enhance lipid yield for biodiesel production.

    OBJECTIVE: The main objective of this study was to explore oleaginous yeast, Yarrowia lipolytica isolated from soil and optimization of culture conditions and medium components to obtained better quality microbial oil for biodiesel production.

    METHODS: Fifty yeast strains were isolated from soil from different regions of Lahore and eleven of them were selected for oil production. The isolated yeast colonies were screened to further check their lipid producing capabilities by the qualitative analysis. Five yeast strains were designated as oleaginous because they produced more than 16% of oil based on their biomass. To estimate the total lipid content of yeast cells, the extraction of lipids was done by performing the procedure proposed by Bligh and Dyer. The transesterification of yeast oils was performed by using different methods. There were three different strategies customized to transesterifying microbial oil using base catalyzed transesterification, acid catalyzed transesterification and enzyme-based transesterification. After completion of transesterification, sample was used for fatty acid methyl esters (FAMEs) were analyzed by gas-chromatograph with ionization detector type MS.

    RESULTS: The isolate IIB-10 identified as Yarrowia lipolytica produced maximum amount of lipids i.e. 22.8%. More amount of biomass was obtained when cane molasses was utilized as carbon source where it produced 29.4 g/L of biomass while sucrose and lactose were not utilized by IIB-10 and no biomass was obtained. Similarly, meat extracts showed best results when it was used as nitrogen source because it resulted in 35.8 g/L biomass of Yarrowia lipolytica IIB-10. The culturing conditions like size of inoculum, effect of pH and time of incubation were also studied. The 10% of inoculum size produced 25.4 g/L biomass at 120 h incubation time, while the pH 7 was the optimum pH at which 24.8 g/L biomass was produced by Yarrowia lipolytica IIB-10. GC-MS analysis showed that biodiesel produced by transesterification contained similar fatty acids as found in vegetable oil for this reason it is widely accepted feedstock for biodiesel production.

    CONCLUSION: The analysis of fatty acids methyl esters showed the similar composition of microbial oil as in vegetable oils and high amount of methyl esters were obtained after transesterification. Therefore, potentially oleaginous yeast could be used to generate a large amount of lipids for biodiesel production that will be the better substitute of petroleum-based diesel and will also control the environmental pollution.

    Matched MeSH terms: Yeast, Dried
  15. Lipid biosynthesis in Cunninghamella bainieri 2A1 in N-limited and N-excess media
    Taha EM, Omar O, Yusoff WM, Hamid AA
    Annals of microbiology, 2010 Dec;60(4):615-622.
    PMID: 21125005
    Lipid biosynthesis and fatty acids composition of oleaginous zygomycetes, namely Cunninghamella bainieri 2A1, cultured in media with excess or limited nitrogen were quantitatively determined at different times of culture growth. Accumulation of lipids occurred even when the activity of NAD(+)-ICDH (β-Nicotinamide adenine dinucleotide-isocitrate dehydrogenase) was still detectable in both media. In C. bainieri 2A1, under nitrogen limitation, the ratio of lipids was around 35%, whereas in nitrogen excess medium (feeding media supplemented with ammonium tartarate), the lipid ratio decreased. The amount of this decrease depended on the level of ammonium tartarate in the media. The main findings in this paper were that C. bainieri 2A1 has the ability to accumulate lipid although nitrogen concentration detected inside the media and that NAD-ICDH was active in all culture periods. These results proved that the strain C. bainieri 2A1 has an alternative behavior in lipid biosynthesis that differs from yeast. According to the old hypotheses, yeasts could not accumulate lipid more than 10% when nitrogen was detected inside the media. Nitrogen-limited and excess media both contained the same fatty acids (palmitic acid, stearic acid, olic acid, linoleic acid and γ-linolenic acid), but at different concentrations. The C:N ratio was also studied and showed no effects on total lipid accumulation, but a significant effect on γ-linolenic acid concentration.
    Matched MeSH terms: Yeast, Dried
  16. Sago starch and its utilisation
    Abd-Aziz S
    J Biosci Bioeng, 2002;94(6):526-9.
    PMID: 16233345
    The importance and development of industrial biotechnology processing has led to the utilisation of microbial enzymes in various applications. One of the important enzymes is amylase, which hydrolyses starch to glucose. In Malaysia, the use of sago starch has been increasing, and it is presently being used for the production of glucose. Sago starch represents an alternative cheap carbon source for fermentation processes that is attractive out of both economic and geographical considerations. Production of fermentable sugars from the hydrolysis of starches is normally carried out by an enzymatic processes that involves two reaction steps, liquefaction and saccharification, each of which has different temperature and pH optima with respect to the maximum reaction rate. This method of starch hydrolysis requires the use of an expensive temperature control system and a complex mixing device. Our laboratory has investigated the possibility of using amylolytic enzyme-producing microorganisms in the continuous single-step biological hydrolysis of sago flour for the production of a generic fermentation medium. The ability of a novel DNA-recombinated yeast, Saccharomyces cerevisiae strain YKU 107 (expressing alpha-amylase production) to hydrolyse gelatinised sago starch production has been studied with the aim of further utilizing sago starch to obtain value-added products.
    Matched MeSH terms: Yeast, Dried
  17. Fulltext Numerical Analysis of Hydrodynamic Flow in Microfluidic Biochip for Single-Cell Trapping Application
    Khalili AA, Ahmad MR
    Int J Mol Sci, 2015;16(11):26770-85.
    PMID: 26569218 DOI: 10.3390/ijms161125987
    Single-cell analysis has become the interest of a wide range of biological and biomedical engineering research. It could provide precise information on individual cells, leading to important knowledge regarding human diseases. To perform single-cell analysis, it is crucial to isolate the individual cells before further manipulation is carried out. Recently, microfluidic biochips have been widely used for cell trapping and single cell analysis, such as mechanical and electrical detection. This work focuses on developing a finite element simulation model of single-cell trapping system for any types of cells or particles based on the hydrodynamic flow resistance (Rh) manipulations in the main channel and trap channel to achieve successful trapping. Analysis is carried out using finite element ABAQUS-FEA™ software. A guideline to design and optimize single-cell trapping model is proposed and the example of a thorough optimization analysis is carried out using a yeast cell model. The results show the finite element model is able to trap a single cell inside the fluidic environment. Fluid's velocity profile and streamline plots for successful and unsuccessful single yeast cell trapping are presented according to the hydrodynamic concept. The single-cell trapping model can be a significant important guideline in designing a new chip for biomedical applications.
    Matched MeSH terms: Yeast, Dried
  18. Fulltext The effect of synbiotic Streptococcus salivarius K12 and Musa acuminata on Candida albicans biofilm formation
    Nurul Alia Risma Rismayuddin, Munirah Mokhtar, Noratikah Othman, Ahmad Faisal Ismail, Mohd Hafiz Arzmi
    Malaysian Journal of Medicine and Health Sciences, 2019;15(108):37-37.
    MyJurnal
    Introduction:Candida albicans is an opportunistic fungus that is associated with oral carcinogenesis. In addition, biofilm formation has been one of the important virulence factors of the yeast. Streptococcus salivarius K12 is an oral probiotic while Musa acuminata is a well-known prebiotic. The objective of this study is to investigate the effect of S. salivarius K12 and M. acuminata skin aqueous extract (synbiotic) on C. albicans with the hypothesis that S. salivariusK12 and M. acuminata inhibit C. albicans biofilm formation. Methods: To develop mono-species biofilm, C. albicans(ATCC MYA-4901 and cancer isolates, ALC2 and ALC3 strains) and S. salivarius K12 were standardised to 105 cells and 106 cells, respectively and grown in 96-well plate in nutrient broth (NB) or RPMI at 37 °C for 72 h. Polymicro-bial biofilms were developed by inoculating both microorganisms in the same well with similar cell number as in mono-species. To determine the effect of synbiotic, similar protocol was repeated by mixing with 800 mg mL-1 of M. acuminata skin extract and incubated at 37 °C for 72 h. The medium was replenished at every 24 h, aseptically. Finally, the biofilms were assessed using crystal violet assay and the optical density was measured at OD620nm. Results:C. albicans strain MYA-4901 and ALC3, when grown in polymicrobial with S. salivarius K12 in NB that is predominated by yeast-form C. albicans, exhibited decreased biofilms by 71.40±11.7% and 49.40±3.9%, respec-tively when compared to the expected biofilms. Meanwhile in RPMI, which C. albicans strain ATCC MYA-4901, ALC2 and ALC3 were predominated by hyphal-form showed decreased biofilms by 72.0±26.7%, 53.4±14.4% and 65.7±6.7%, respectively when compared to the expected biofilms. Conclusion:S. salivarius K12 and M. acuminata skin extract synbiotic inhibit biofilm formation of C. albicans yeast and hyphal forms thus supported the hypothesis of the present study.
    Matched MeSH terms: Yeast, Dried
  19. Fulltext Effect of fennel (Foeniculum vulgare Mill.) and coriander (Coriandrum sativum L.) on microbial quality and sensory acceptability of frozen paratha
    Rosli, N.A., Azilan, N A., Mahyudin, N.A., Mahmud Ab Rashid, N.K., Meon, F.N.S., Ismail, Z., et al.
    International Food Research Journal, 2019;26(3):945-952.
    MyJurnal
    Fennel (Foeniculum vulgare Mill.) and coriander (Coriandrum sativum L.) are known to possess good antimicrobial properties. In the present work, spice-infused frozen parathas were formulated to investigate the effect of fennel and coriander on microbial (aerobic mesophilic bacteria, yeast and mould, and Bacillus cereus) reduction and sensory acceptability of frozen paratha throughout the storage at -18°C. The present work was also aimed at determining the relationship between spice concentrations and storage durations on microbiological quality of the samples. Fennel and coriander seed powder were used at concentrations of 2, 4 and 6% of wheat flour (w/w). The microbiological analysis was performed by total plate count, yeast and mould count, and Bacillus cereus count after 9, 12 and 15 weeks of storage. Sensory evaluation was conducted using hedonic scales at the end of storage durations. Results showed that spice infusion in frozen paratha significantly delayed the growth of aerobic mesophilic bacteria, yeasts and moulds, and Bacillus cereus during storage. The lowest log count was demonstrated by coriander at 6% in total plate count (3.85, 3.90 and 3.91 log10 CFU/g), and yeast and mould count (2.54, 2.59 and 2.60 log10 CFU/g) after 9, 12 and 15 weeks, respectively. Bacillus cereus was not detected throughout the storage durations. Fennel exhibited minimum activity against Bacillus cereus with no significant difference on log count reduction when compared with control. Coriander showed the highest decrease in both total plate count and Bacillus cereus count during the storage duration. Sensory evaluation result indicated that control sample exhibited the highest preference over all attributes when compared with fennel and coriander. Coriander-infused paratha was slightly darker in colour due to high concentration of 6%. Fennel yielded the lowest score in terms of taste among all samples. Fennel and coriander showed no significant difference for sensory acceptability. Overall, all frozen parathas were in good quality after 15 weeks of frozen storage. It can thus be concluded that fennel and coriander can be used as potential natural preservatives to inhibit the growth of microorganisms in paratha during frozen storage. Nevertheless, the optimum spice concentration should be determined to minimise the effects on the sensory attributes.
    Matched MeSH terms: Yeast, Dried
  20. Fulltext Potential of Zeolite and Algae in Biomass Immobilization
    Emami Moghaddam SA, Harun R, Mokhtar MN, Zakaria R
    Biomed Res Int, 2018;2018:6563196.
    PMID: 30643814 DOI: 10.1155/2018/6563196
    The interest in utilizing algae for wastewater treatment has been increased due to many advantages. Algae-wastewater treatment system offers a cost-efficient and environmentally friendly alternative to conventional treatment processes such as electrocoagulation and flocculation. In this biosystem, algae can assimilate nutrients in the wastewater for their growth and simultaneously capture the carbon dioxide from the atmosphere during photosynthesis resulting in a decrease in the greenhouse gaseousness. Furthermore, the algal biomass obtained from the treatment process could be further converted to produce high value-added products. However, the recovery of free suspended algae from the treated effluent is one of the most important challenges during the treatment process as the current methods such as centrifugation and filtration are faced with the high cost. Immobilization of algae is a suitable approach to overcome the harvesting issue. However, there are some drawbacks with the common immobilization carriers such as alginate and polyacrylamide related to low stability and toxicity, respectively. Hence, it is necessary to apply a new carrier without the mentioned problems. One of the carriers that can be a suitable candidate for the immobilization is zeolite. To date, various types of zeolite have been used for the immobilization of cells of bacteria and yeast. If there is any possibility to apply them for the immobilization of algae, it needs to be considered in further studies. This article reviews cell immobilization technique, biomass immobilization onto zeolites, and algal immobilization with their applications. Furthermore, the potential application of zeolite as an ideal carrier for algal immobilization has been discussed.
    Matched MeSH terms: Yeast, Dried
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