METHODS AND RESULTS: The effects of unfractionated CTs (F0) and CT fractions of different MWs (F1 > F2 > F3 > F4 > F5) on protozoal population and community were evaluated in vitro using rumen microbes and ground guinea grass as the substrate. Higher-MW CT fractions F1 and F2 significantly (P
METHODS AND RESULTS: Based on the sequences of internal transcribed spacer (ITS), TEF1-α and β-tubulin, as well as on the phylogenetic analysis of combined sequences, four species of Lasiodiplodia (L. theobromae,L. pseudotheobromae, L. iranensis, L. mahajangana) and two species of Neofusicoccum (N. ribis, N. parvum) were identified. Pseudofusicoccum violaceum, Neoscytalidium dimidiatum and three species of Botryosphaeria (B. scharifii, B. dothidea, B. ramosa) were identified based on sequences of ITS and TEF1-α. Pathogenicity test of selected isolates were tested on Chok Anan, Waterlily and Falan mango cultivars. Generally, all species were observed to be pathogenic on the three tested mango cultivars on wounded fruits, except for N. ribis and N. parvum, which were pathogenic on both wounded and unwounded fruits. However, N. ribis was only pathogenic on cultivar Falan, whereas B. ramosa were pathogenic on cultivars Waterlily and Falan.
CONCLUSIONS: Eleven species of Botryosphaeriaceae were associated with mango stem-end rot in Malaysia. To the best of our knowledge, four species, namely L. mahajangana, B. ramosa, N. ribis and P. violaceum are the first recorded Botryosphaeriaceae fungi associated with stem end rot of mango.
SIGNIFICANCE AND IMPACT OF THE STUDY: The identification of Botryosphaeriaceae fungi is important to establish suitable control measures and quarantine requirements. Many species have a wide host range, which means that there is a possibility of cross infection from other infected plants.
METHODS AND RESULTS: In this study, recombinant TYMVcHis6 expressed in Escherichia coli self-assembled into VLPs of approximately 30-32 nm. SDS-PAGE and Western blot analysis of protein fractions from the immobilized metal affinity chromatography (IMAC) showed that TYMVcHis6 VLPs interacted strongly with nickel ligands in IMAC column, suggesting that the fusion peptide is protruding out from the surface of VLPs. These VLPs are highly stable over a wide pH range from 3·0 to 11·0 at different temperatures. At pH 11·0, specifically, the VLPs remained intact up to 75°C. Additionally, the disassembly and reassembly of TYMVcHis6 VLPs were studied in vitro. Dynamic light scattering and transmission electron microscopy analysis revealed that TYMVcHis6 VLPs were dissociated by 7 mol l-1 urea and 2 mol l-1 guanidine hydrochloride (GdnHCl) without impairing their reassembly property.
CONCLUSIONS: A 10-residue peptide was successfully displayed on the surface of TYMVcHis6 VLPs. This chimera demonstrated high stability under extreme thermal conditions with varying pH and was able to dissociate and reassociate into VLPs by chemical denaturants.
SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first C-terminally modified TYMVc produced in E. coli. The C-terminal tail which is exposed on the surface can be exploited as a useful site to display multiple copies of functional ligands. The ability of the chimeric VLPs to self-assemble after undergo chemical denaturation indicates its potential role to serve as a nanocarrier for use in targeted drug delivery.
METHODS AND RESULTS: The leaves of D. linearis were subjected to sonication-assisted extraction using hexane (HEX), dichloromethane, ethyl acetate and methanol (MeOH). It was found that only the MeOH fraction exhibited antimicrobial activity using broth microdilution assay; while all four fractions do not exhibit biofilm inhibition activity against S. aureusATCC 6538P, S. aureusATCC 43300, S. aureusATCC 33591 and S. aureusATCC 29213 using crystal violet assay. Among the four fractions tested, only the HEX fraction showed biofilm disrupting ability, with 60-90% disruption activity at 5 mg ml-1against all four S. aureus strains tested. Bioassay-guided purification of the active fraction has led to the isolation of α-tocopherol. α-Tocopherol does not affect the cells within the biofilms but instead affects the biofilm matrix in order to disrupt S. aureus biofilms.
CONCLUSIONS: α-Tocopherol was identified to be the bioactive component of D. linearis with disruption activity against S. aureus biofilm matrix.
SIGNIFICANCE AND IMPACT OF THE STUDY: The use of α-tocopherol as a biofilm disruptive agent might potentially be useful to treat biofilm-associated infections in the future.
METHODS AND RESULTS: Extracts were obtained via sequential solvent extraction method using hexane, dichloromethane, ethyl acetate, methanol and water. Antimicrobial activity testing was done using broth microdilution assay against 17 strains of bacteria. The leaf hexane extract of E. coccinea and rhizome hexane extract of E. sessilanthera showed best antimicrobial activities, with minimum inhibitory concentration (MIC) values ranging from 0·016 to 1 mg ml-1 against Gram-positive bacteria. From these active extracts, two antimicrobials were isolated and identified as trans-2-dodecenal and 8(17),12-labdadiene-15,16-dial with MIC values ranging from 4 to 8 μg ml-1 against Bacillus cereus, Bacillus subtilis and Staphylococcus aureus.
CONCLUSION: Etlingera coccinea and E. sessilanthera demonstrated good antimicrobial activities against clinically relevant bacteria strains. The antimicrobial compounds isolated showed low MIC values, hence suggesting their potential use as antimicrobial agents.
SIGNIFICANCE AND IMPACT OF THE STUDY: This study is the first to identify the potent antimicrobials from these gingers. The antimicrobials isolated could potentially be developed further for use in treatment of bacterial infections. Also, this study warrants further research into other Etlingera species in search for more antimicrobial compounds.
METHODS AND RESULTS: The crude extracts of E. pubescens were obtained through methanol extraction, and evaluated for antimicrobial activities. From this extract, 1,7-bis(3,4-dihydroxyphenyl)heptan-3-yl acetate (etlingerin) was isolated. When compared to curcumin (a compound with a similar chemical structure), etlingerin showed twofold lower minimum inhibitory concentration values while also being bactericidal. Through time kill assay, etlingerin showed rapid killing effects (as fast as 60 min) against the Gram-positive bacteria (Staphylococcus aureus ATCC 43300 and Bacillus subtilis ATCC 8188). Further assessment revealed that etlingerin caused leakage of intracellular materials, therefore suggesting alteration in membrane permeability as its antimicrobial mechanism. Cytotoxicity study demonstrated that etlingerin exhibited approximately 5- to 12-fold higher IC50 values against several cell lines, as compared to curcumin.
CONCLUSIONS: Etlingerin isolated from E. pubescens showed better antibacterial and cytotoxic activities when compared to curcumin. Etlingerin could be safe for human use, though further cytotoxicity study using animal models is needed.
SIGNIFICANCE AND IMPACT OF THE STUDY: Etlingerin has a potential to be used in treating bacterial infections due to its good antimicrobial activity, while having potentially low cytotoxicity.
METHODS AND RESULTS: Wild-type flies (Oregon-R) were crossed with glass multimer reporter-GAL4 (GMR-GAL4) to produce GMR-OreR (Control), while UAS-Aβ42 (#33769) were crossed with GMR-GAL4 to produce transgenic Drosophila line that expressed Aβ42 (GMR-Aβ42). Feed containing seven different LAB strains (Lactobacillus paracasei 0291, Lactobacillus helveticus 1515, Lactobacillus reuteri 30242, L. reuteri 8513d, Lactobacillus fermentum 8312, Lactobacillus casei Y, Lactobacillus sakei Probio65) were given to GMR-Aβ42 respectively, while feed without LAB strains were given to control and transgenic GMR-Aβ42.nf Drosophila lines. The morphology of the eyes was viewed with scanning electron microscopy (SEM). The changes in gut microbiota profiles associated with LAB were analysed using 16s high throughput sequencing. Malformation of eye structures in transgenic GMR-Aβ42 Drosophila were reversed upon the administration of LAB strains, with more prevalent effects from L. sakei Probio65 and L. paracasei 0291. The GMR-Aβ42.nf group showed dominance of Wolbachia in the gut, a genus that was almost absent in the normal control group (P
METHODS AND RESULTS: Ara h 2.02 cDNA was cloned into pNZ8048 for heterologous expression in L. lactis. The purified recombinant allergen showed IgE binding comparable with native Ara h 2. Balb/c mice were fed with either recombinant (rLl), nonrecombinant L. lactis (Ll) or NaHCO3 (Sham) prior to sensitization and challenged with rAra h 2.02, whereas the baseline group was only fed with Ll. Allergen-specific immunoglobulin and splenocyte cytokines responses were determined for each mouse. Mice fed with either Ll or rLl showed significant alleviation of IgE and IgG1 compared to the Sham group. Despite no significant decrease in Th2 (IL-4, IL-13, IL-6) or increase in Th1 (IFN-γ) cytokines, both groups showed lower IL-10 level, while the IL-4 : IFN-γ ratio was significantly lower for rLl compared to Ll group.
CONCLUSIONS: Oral administration of rLl harbouring Ara h 2.02 demonstrated alleviation of Th2-associated responses in allergen-challenged mice and a possible added allergen-specific prophylactic effect.
SIGNIFICANCE AND IMPACT OF THE STUDY: Ara h 2.02 coupled with the intrinsic properties of probiotic L. lactis as a delivery vehicle can be explored for the development of a commercially scalable vaccine.
METHODS AND RESULTS: The anti-ageing mechanism of three probiotics strains Lactobacillus fermentum DR9, Lactobacillus paracasei OFS 0291 and L. helveticus OFS 1515 were evaluated on gastrocnemius muscle and tibia of d-galactose-induced ageing rats. Upon senescence induction, aged rats demonstrated reduced antioxidative genes CAT and SOD expression in both bone and muscle compared to the young rats (P
METHODS AND RESULTS: The lactobacilli putative probiotic (SynForU-HerCare; two capsules/day of 9·5 log CFU per capsule) or placebo was administered for 8-weeks in a randomized, double-blind, placebo-controlled study. Subjects were assessed for vaginal and gut health conditions at baseline, week-4 and week-8 via questionnaires. The vulvovaginal symptom questionnaire not only covered aspects pertaining to vulvovaginal symptoms but also the quality of life impacts such as emotional, social and sexual. The administration of lactobacilli reduced symptoms of irritation (P = 0·023) and discharge (P = 0·011) starting week-4 and continued after week-8 (P
METHODS AND RESULTS: The POME final discharge, upstream (unpolluted by POME), and downstream (effluent receiving point) parts of the rivers from two sites were physicochemically characterized. The taxonomic and gene profiles were then evaluated using de novo metatranscriptomics, while the metabolites were detected using qualitative metabolomics. A similar bacterial community structure in the POME final discharge samples from both sites was recorded, but their composition varied. Redundancy analysis showed that several families, particularly Comamonadaceae and Burkholderiaceae [Pr(>F) = 0.028], were positively correlated with biochemical oxygen demand (BOD5) and chemical oxygen demand (COD). The results also showed significant enrichment of genes regulating various metabolisms in the POME-receiving rivers, with methane, carbon fixation pathway, and amino acids among the predominant metabolisms identified (FDR 4, and PPDE > 0.95). This was further validated through qualitative metabolomics, whereby amino acids were detected as the predominant metabolites.
CONCLUSIONS: The results suggest that genes regulating amino acid metabolism have significant potential for developing effective biomonitoring and bioremediation strategies in river water influenced by POME final discharge, fostering a sustainable palm oil industry.
METHODS AND RESULTS: In our work, 10 naturally occurring phenolic compounds were evaluated for their inhibitory potential towards the lignolytic enzymes of G. boninense. Additionally, the lignin-degrading enzymes were characterized. Most of the peholic compounds exhibited an uncompetitive inhibition towards the lignin-degrading enzymes. Benzoic acid was the superior inhibitor to the production of lignin-degrading enzymes, when compared between the 10 phenolic compounds. The inhibitory potential of the phenolic compounds towards the lignin-degrading enzymes are higher than that of the conventional metal ion inhibitor. The lignin-degrading enzymes were stable in a wide range of pH but were sensitive to higher temperature.
CONCLUSION: The study demonstrated the inhibitor potential of 10 naturally occurring phenolic compounds towards the lignin-degrading enzymes of G. boninense with different efficacies.
SIGNIFICANCE AND IMPACT OF THE STUDY: The study has shed a light towards a new management strategy to control basal stem rot disease in oil palm. It serves as a replacement for the existing chemical control.
METHODS AND RESULTS: Ten naturally occurring phenolic compounds were assessed for their inhibitory effect on the hydrolytic enzymes of G. boninense. The enzyme kinetics (Vmax and Km ) and the stability of the hydrolytic enzymes were also characterized. The selected compounds had shown inhibitory effect at various concentrations. Two types of inhibitions namely uncompetitive and noncompetitive were observed in the presence of phenolic compounds. Among all the phenolic compounds tested, benzoic acid was the most effective compound suppressive to the growth and production of hydrolytic enzymes secreted by G. boninense. The phenolic compounds as inhibitory agents can be a better replacement for the metal ions which are known as conventional inhibitors till date. The three hydrolytic enzymes were stable in a wide range of pH and temperature.
CONCLUSION: These findings highlight the efficacy of the applications of phenolic compounds to control Ganoderma.
SIGNIFICANCE AND IMPACT OF THE STUDY: The study has proved a replacement for chemical controls of G. boninense with naturally occurring phenolic compounds.