Umi Kalsom Yusuf

Genotoxicity of Euphorbia hirta: An Allium cepa Assay

The potential genotoxic effects of methanolic extracts of Euphorbia hirta which is commonly used in traditional medicine to treat a variety of diseased conditions including asthma, coughs, diarrhea and dysentery was investigated using Allium cepa assay. The extracts of 125, 250, 500 and 1,000 µg/mL were tested on root meristems of A. cepa. Ethylmethanesulfonate was used as positive control and distilled water was used as negative control. The result showed that mitotic index decreased as the concentrations of E. hirta extract increased. A dose-dependent increase of chromosome aberrations was also observed. Abnormalities scored were stickiness, c-mitosis, bridges and vagrant chromosomes. Micronucleated cells were also observed at interphase. Result of this study confirmed that the methanol extracts of E. hirta exerted significant genotoxic and mitodepressive effects at 1,000 µg/mL.

Differential expression of oil palm pathology genes during interactions with Ganoderma boninense and Trichoderma harzianum.

The expression profiles of Δ9 stearoyl-acyl carrier protein desaturase (SAD1 and SAD2) and type 3 metallothionein (MT3-A and MT3-B) were investigated in seedlings of oil palm (Elaeis guineensis) artificially inoculated with the pathogenic fungus Ganoderma boninense and the symbiotic fungus Trichoderma harzianum. Expression of SAD1 and MT3-A in roots and SAD2 in leaves were significantly up-regulated in G. boninense inoculated seedlings at 21 d after treatment when physical symptoms had not yet appeared and thereafter decreased to basal levels when symptoms became visible. Our finding demonstrated that the SAD1 expression in leaves was significantly down-regulated to negligible levels at 42 and 63 d after treatment. The transcripts of MT3 genes were synthesized in G. boninense inoculated leaves at 42 d after treatment, and the analyses did not show detectable expression of these genes before 42 d after treatment. In T. harzianum inoculated seedlings, the expression levels of SAD1 and SAD2 increased gradually and were stronger in roots than leaves, while for MT3-A and MT3-B, the expression levels were induced in leaves at 3d after treatment and subsequently maintained at same levels until 63d after treatment. The MT3-A expression was significantly up-regulated in roots at 3d after treatment and thereafter were maintained at this level. Both SAD and MT3 expression were maintained at maximum levels or at levels higher than basal. This study demonstrates that oil palm was able to distinguish between pathogenic and symbiotic fungal interactions, thus resulting in different transcriptional activation profiles of SAD and MT3 genes. Increases in expression levels of SAD and MT3 would lead to enhanced resistance against G. boninense and down-regulation of genes confer potential for invasive growth of the pathogen. Differences in expression profiles of SAD and MT3 relate to plant resistance mechanisms while supporting growth enhancing effects of symbiotic T. harzianum.

Morphological and molecular detection of Fusarium chlamydosporum from root endophytes of Dendrobium crumenatum

Fusarium has a cosmopolitan distribution, with some species able to cause diseases in agricultural crops. A number of isolates of endophytic fungi were isolated from healthy roots of Dendrobium crumenatum (Orchidaceae) at Universiti Putra Malaysia campus. The isolates were primarily identified as Fusarium chlamydosporum based on morphological characteristics. The cultures were produced in a range of chicory pink to red and brown pigmentation. Only morphological studies of Fusarium can not give any guarantee at the species levels of identification but key the putative species names. Therefore, molecular studies based on gene sequencing of the internal transcribed spacer 1 and 2 regions of the ribosomal DNA (rDNA) were carried out. The amplified DNA was sequenced and aligned against the reference sequences, previously identified as Fusarium species. Results obtained have shown that all of the isolates putatively identified as F. chlamydosporum were in agreement with the ex-type strains of F. chlamydosporum gene sequences collected from the GenBank database. Thus, data from the present study suggested that the best conceivable connection between the morphological characters and the molecular characters are to use sequence based analysis of the ITS 1/2 regions of the rDNA of the original specimen at the same times as it could be removed any kind of controversial identification of F. chlamydosporum at the species level.

Flavonoid glycosides in the leaves of Mimosa species

Mimosa L., a genus of pantropical legumes, contains 300–400 species with a heavy concentration of species in South America (Neilson, 1992). In Malaysia, Mimosa pudica L., M. quadrivalvis L. var. leptocarpa (DC.) Barneby, (syn: M. longihirsuta), M. pigra L. and M. invisa Mart. var. invisa are known as weedy elements that infest large areas of agricultural, residential, recreational, roadsides and derelict areas and ex-mining lands. Fresh leaves of the four species were collected from Bidong (Kedah) and Bidor (Perak). Representative voucher specimens of M. pudica (KLU22499), M. pigra (KLU-44404), M. quadrivalvis L. var. leptocarpa (KLU 44405) and M. invisa (KLU-001272) were deposited in the University of Malaya herbarium, Kuala Lumpur (KLU).

Antimicrobial effects of allicin and ketoconazole on trichophyton rubrum under in vitro condition

Dermatophytosis is caused by a group of pathogenic fungi namely, dermatophytes, is among the most prevalent infectious diseases worldwide. Azole drugs are widely used in the treatment of dermatomycosis, but can cause various side effects and drug resistance to the patients. Hence, for solving this problem can be used from the plant extract as alternative for chemical drugs. Allicin is a pure bioactive compound isolated from garlic was tested for its potential as a treatment of dermatomycosis in this study. This study evaluated the in vitro efficacy of pure allicin against ten isolates of Trichophyton rubrum and the MIC50 and MIC90 ranged from 0.78-12.5 μg/ml for allicin. The results revealed that the order of efficacy based on the MICs values, all isolates showed almost comparable response to allicin and ketoconazole except for some isolates, at 28 °C for both 7 and 10 days incubation. Mann-Whitney test indicate that MICs at 7 days incubation was not observed a significant difference between the effects of allicin and ketoconazole (p > 0.05), but MICs at 10 days incubation, a significant difference was observed (p ≤ 0.05). On the other side, time kill studies revealed that allicin used its fungicidal activity within 12-24 h of management in vitro as well as ketoconazole. In conclusion, allicin showed very good potential as an antifungal compound against mycoses-causing dermatophytes, almost the same as the synthetic drug ketoconazole. Therefore, this antifungal agent appears to be effective, safe and suitable alternative for the treatment of dermatomycosis.

mRNA Expression of EgCHI1, EgCHI2, and EgCHI3 in Oil Palm Leaves (Elaeis guineesis Jacq.) after Treatment with Ganoderma boninense Pat. and Trichoderma harzianum Rifai

Background. Basal stem rot (BSR) disease caused by the fungus Ganoderma boninense is the most serious disease affecting the oil palm; this is because the disease escapes the early disease detection. The biocontrol agent Trichoderma harzianum can protect the disease only at the early stage of the disease. In the present study, the expression levels of three oil palm (Elaeis guineensis Jacq.) chitinases encoding EgCHI1, EgCHI2, and EgCHI3 at 2, 5, and 8 weeks inoculation were measured in oil palm leaves from plants treated with G. boninense or T. harzianum alone or both. Methods. The five-month-old oil palm seedlings were treated with Gano-wood blocks inoculum and trichomulch. Expression of EgCHI1, EgCHI2, and EgCHI3 in treated leaves tissue was determined by real-time PCR. Results. Oil palm chitinases were not strongly expressed in oil palm leaves of plants treated with G. boninense alone compared to other treatments. Throughout the 8-week experiment, expression of EgCHI1 increased more than 3-fold in leaves of plants treated with T. harzianum and G. boninense when compared to those of control and other treated plants. Conclusion. The data illustrated that chitinase cDNA expression varied depending on tissue and the type of treatment.

Conventional and molecular characterization of Trichophyton rubrum

Different studies illustrated that Trichophyton rubrum, among all species of Trichophyton, is the most prevalent and consequently the most important genus. T. rubrum as a worldwide filamentous pathogen fungus can infect human keratinized tissue (skin, nails and rarely hair), and causes dermatophytosis. Researchers use two general methods for the identification of dermatophytes namely, conventional methods on the basis of phenotype variations and molecular methods on the basis of molecular differences. Due to some limitations in traditional methods, in the recent years, molecular biological methods are regarded as useful in the exact and rapid recognition of dermatophytes. The present study identified nine clinical isolates and one ATCC as a control strain of T. rubrum by using both conventional and molecular methods. The molecular systematics method was used to elucidate genetic diversity among strains of T. rubrum and within Trichophyton species. Morphological characteristics of all colonies T. rubrum quite varies among each other; we revealed that that conventional methods are generally prolonged and may be indecisive. However, molecular studies based on internal transcribed spacer (ITS) sequencing provides a very accurate result, which is more than 96% the similarity of T. rubrum among all isolates, and more than 90% similarity within Trichophyton spp.

Storage behaviour of exotic potato genotypes and hybrid clones under natural condition

An experiment was conducted to evaluate the storability of hybrid clones and exotic genotypes at room temperature during April to August 2011 and April to August 2012. Fourteen hybrid clones and 14 exotic genotypes were stored for five months at ambient temperature. Hybrid clones 7.33 and 7.12 showed better performance in respect of storage behaviour (minimum weight and rottage loss) at ambient temperature. The maximum storability was found in Labadia, Liseta, Albaata, Lambada and Amanda exotic genotypes. Moreover, hybrid clones 7.33 and 7.12 exhibited minimum weight and rottage loss in both the hybrid clones and the exotic genotypes. Based on their storage behaviour at ambient temperature, it may be concluded that hybrid clones 7.33 and 7.12 are found to be suitable for storage under ordinary room temperature conditions for a period of 90 to 120 days and slow release to market for avoiding distress sale.