Ahmad Aziz

Cinnamic acid, coumarin and vanillin: Alternative phenolic compounds for efficient Agrobacterium-mediated transformation of the unicellular green alga, Nannochloropsis sp.

The use of acetosyringone in Agrobacterium-mediated gene transfer into plant hosts has been favored for the past few decades. The influence of other phenolic compounds and their effectiveness in Agrobacterium-mediated plant transformation systems has been neglected. In this study, the efficacy of four phenolic compounds on Agrobacterium-mediated transformation of the unicellular green alga Nannochloropsis sp. (Strain UMT-M3) was assessed by using β-glucuronidase (GUS) assay. We found that cinnamic acid, vanillin and coumarin produced higher percentages of GUS positive cells as compared to acetosyringone. These results also show that the presence of methoxy group in the phenolic compounds may not be necessary for Agrobacterium vir gene induction and receptor binding as suggested by previous studies. These findings provide possible alternative Agrobacterium vir gene inducers that are more potent as compared to the commonly used acetosyringone in achieving high efficiency of Agrobacterium-mediated transformation in microalgae and possibly for other plants.

Differential regulation of fatty acid biosynthesis in two Chlorella species in response to nitrate treatments and the potential of binary blending microalgae oils for biodiesel application

This study was undertaken to investigate the effects of different nitrate concentrations in culture medium on oil content and fatty acid composition of Chlorella vulgaris (UMT-M1) and Chlorella sorokiniana (KS-MB2). Results showed that both species produced significant higher (p<0.05) oil content at nitrate ranging from 0.18 to 0.66 mM with C. vulgaris produced 10.20-11.34% dw, while C. sorokiniana produced 15.44-17.32% dw. The major fatty acids detected include C16:0, C18:0, C18:1, C18:2 and C18:3. It is interesting to note that both species displayed differentially regulated fatty acid accumulation patterns in response to nitrate treatments at early stationary growth phase. Their potential use for biodiesel application could be enhanced by exploring the concept of binary blending of the two microalgae oils using developed mathematical equations to calculate the oil mass blending ratio and simultaneously estimated the weight percentage (wt.%) of desirable fatty acid compositions.

The apoptotic effect of 1′S-1′-acetoxychavicol acetate from Alpinia conchigera on human cancer cells.

1’-(S)-1’-Acetoxychavicol acetate (ACA) isolated from the Malaysian ethno-medicinal plant Alpinia conchigera Griff. was investigated for its potential as an anticancer drug. In this communication, we describe the cytotoxic and apoptotic properties of ACA on five human tumour cell lines. Data from MTT cell viability assays indicated that ACA induced both time- and dose-dependent cytotoxicity on all tumour cell lines tested and had no adverse cytotoxic effects on normal cells. Total mortality of the entire tumour cell population was achieved within 30 hrs when treated with ACA at 40.0 µM concentration. Flow cytometric analysis for annexin-V and PI dual staining demonstrated that cell death occurred via apoptosis, followed by secondary necrosis. The apoptotic effects of ACA were confirmed via the DNA fragmentation assay, in which consistent laddering of genomic DNA was observed for all tumour cell lines after a 24 hrs post-treatment period at the IC50 concentration of ACA. A cell cycle analysis using PI staining also demonstrated that ACA induced cell cycle arrest at the G0/G1 phase, corresponding to oral tumour cell lines. In conclusion, ACA exhibits enormous potential for future development as a chemotherapeutic drug against various malignancies.

Indole-3-acetic acid (IAA) induced changes in oil content, fatty acid profiles and expression of four fatty acid biosynthetic genes in Chlorella vulgaris at early stationary growth phase.

Microalgae lipids and oils are potential candidates for renewable biodiesel. Many microalgae species accumulate a substantial amount of lipids and oils under environmental stresses. However, low growth rate under these adverse conditions account for the decrease in overall biomass productivity which directly influence the oil yield. This study was undertaken to investigate the effect of exogenously added auxin (indole-3-acetic acid; IAA) on the oil content, fatty acid compositions, and the expression of fatty acid biosynthetic genes in Chlorella vulgaris (UMT-M1). Auxin has been shown to regulate growth and metabolite production of several microalgae. Results showed that oil accumulation was highest on days after treatment (DAT)-2 with enriched levels of palmitic (C16:0) and stearic (C18:0) acids, while the linoleic (C18:2) and α-linolenic (C18:3n3) acids levels were markedly reduced by IAA. The elevated levels of saturated fatty acids (C16:0 and C18:0) were consistent with high expression of the β-ketoacyl ACP synthase I (KAS I) gene, while low expression of omega-6 fatty acid desaturase (ω-6 FAD) gene was consistent with low production of C18:2. However, the increment of stearoyl-ACP desaturase (SAD) gene expression upon IAA induction did not coincide with oleic acid (C18:1) production. The expression of omega-3 fatty acid desaturase (ω-3 FAD) gene showed a positive correlation with the synthesis of PUFA and C18:3n3.

Synthesis, crystal structure, DFT studies and evaluation of the antioxidant activity of 3,4-dimethoxybenzenamine schiff bases.

Schiff bases of 3,4-dimethoxybenzenamine 1–25 were synthesized and evaluated for their antioxidant activity. All the synthesized compounds were characterized by various spectroscopic techniques. In addition, the characterizations of compounds 13, 15 and 16 were supported by crystal X-ray determinations and their geometrical parameters were compared with theoretical DFT calculations at the B3LYP level of theory. Furthermore, the X-ray crystal data of two non-crystalline compounds 8 and 18 were theoretically calculated and compared with the practical values of compounds 13, 15, 16 and found a good agreement. The compounds showed good DPPH scavenging activity ranging from 10.12 to 84.34 μM where compounds 1–4 and 6 showed stronger activity than the standard n-propyl gallate. For the superoxide anion radical assay, compounds 1–3 showed better activity than the standard.

Essential Oils of Elettariopsis curtisii (Zingiberaceae) and Their Antimicrobial Activities

Abstract The essential oils of leaves and rhizomes (fresh and dried) of Elettariopsis curtisii collected from Jeli, Kelantan were isolated by hydrodistillation and were analyzed using capillary GC and GC/MS. The most abundant components in both leaf and rhizome oils were (E)-2-octenal (1.0–19.3%), (E)-2-decenal (17.4–69.4%) and (E)-2-decenoic acid (7.4–57.2%). None of the oils exhibited remarkable inhibition potential against the microbes Microsporum canis, Trichophyton mentagrophytes, Trichophyton rubrum, Pseudomonas aeruginosa, Pseudomonas cepacia, Staphylococcus aureus and Staphylococcus epidermidis except for the fresh rhizome oil which showed an MIC value of 0.938 μg/μL against T. mentagrophytes.

Grandine A, a New Proaporphine Alkaloid from the Bark of Phoebe grandis

The stem bark of Phoebe grandis afforded one new oxoproaporphine; (–)-grandine A (1), along with six known isoquinoline alkaloids: (–)-8,9-dihydrolinearisine (2), boldine, norboldine, lauformine, scortechiniine A and scortechiniine B. In addition to that of the new compound, complete 1H- and 13C-NMR data of the tetrahydroproaporphine (–)-8,9-dihydrolinearisine (2) is also reported. The alkaloids’ structures were elucidated primarily by means of high field 1D- and 2D-NMR and HRMS spectral data.

(E)-N'-(3,4-Dihy-droxy-benzyl-idene)-2,4-dimethyl-benzohydrazide monohydrate.

In the title compound, C16H16N2O3·H2O, the dihedral angle between the benzene rings is 30.27 (7)°. In the crystal, the components are linked by N—H⋯O, O—H⋯O and C—H⋯O interactions into a three-dimensional network.

Metabolites Re-programming and Physiological Changes Induced in Scenedesmus regularis under Nitrate Treatment

Nitrate is required to maintain the growth and metabolism of plant and animals. Nevertheless, in excess amount such as polluted water, its concentration can be harmful to living organisms such as microalgae. Recently, studies on microalgae response towards nutrient fluctuation are usually limited to lipid accumulation for the production of biofuels, disregarding the other potential of microalgae to be used in wastewater treatments and as source of important metabolites. Our study therefore captures the need to investigate overall metabolite changes via NMR spectroscopy approach coupled with multivariate data to understand the complex molecular process under high (4X) and low (1/4X) concentrations of nitrate (