Mourad A. M. Aboul-Soud

Antitumor Properties and Modulation of Antioxidant Enzymes Activity by Aloe vera Leaf Active Principles Isolated via Supercritical Carbon Dioxide Extraction

The aim of this study was to evaluate the potential anticancer properties and modulatory effect of selected Aloe vera (A. vera) active principles on antioxidant enzyme activities. Thus, three anthraquinones (Namely: aloesin, aloe-emodin and barbaloin) were extracted from A. vera leaves by supercritical fluid extraction and subsequently purified by high performance liquid chromatography. Additionally, the N-terminal octapeptide derived from verectin, a biologically active 14 kDa glycoprotein present in A. vera, was also tested. In vivo, active principles exhibited significant prolongation of the life span of tumor-transplanted animals in the following order: barbaloin> octapeptide> aloesin > aloe-emodin. A. vera active principles exhibited significant inhibition on Ehrlich ascite carcinoma cell (EACC) number, when compared to positive control group, in the following order: barbaloin> aloe-emodin > octapeptide > aloesin. Moreover, in trypan blue cell viability assay, active principles showed a significant concentration-dependent cytotoxicity against acute myeloid leukemia (AML) and acute lymphocytes leukemia (ALL) cancerous cells. Furthermore, in MTT cell viability test, aloe-emodin was found to be active against two human colon cancer cell lines (i.e. DLD-1 and HT2), with IC(50) values of 8.94 and 10.78 microM, respectively. Treatments of human AML leukemic cells with active principles (100 microg ml(-1)) resulted in varying intensities of internucleosomal DNA fragmentation, hallmark of cells undergoing apoptosis, in the following order: aloe-emodin> aloesin> barbaloin> octapeptide. Intererstingly, treatment of EACC tumors with active principles resulted in a significant elevation activity of key antioxidant enzymes (SOD, GST, tGPx, and LDH). Our data suggest that the tested A. vera compounds may exert their chemo-preventive effect through modulating antioxidant and detoxification enzyme activity levels, as they are one of the indicators of tumorigenesis. These findings are discussed in the light of the potential of A. vera plant extracts for developing efficient, specific and non-toxic anticancer drugs that are affordable for developing countries.

Improvement of mercuric chloride-induced testis injuries and sperm quality deteriorations by Spirulina platensis in rats.

The present study was undertaken to investigate the protective effect of the filamentous cyanobacterium Spirulina platensis (S. platensis) on mercury (II) chloride (HgCl2)-induced oxidative damages and histopathological alterations in the testis of Wistar albino rats. The animals were divided into four equal groups, i ) control, ii ) HgCl2, iii ) S. platensis and iv ) combination of HgCl2+S. platensis. Oxidative stress, induced by a single dose of HgCl2 (5 mg/kg, bw; subcutaneously, s.c.), substantially decreased (P<0.01) the activity level of testicular key enzymatic antioxidant biomarkers (superoxide dismutase, SOD; catalase, CAT and glutathione peroxidase, GPx), oxidative stress makers (blood hydroperoxide; testicular reduced glutathione, GSH and malondialdehyde, MDA), and testicular mercury levels. Moreover, HgCl2 administration resulted in a significant (P<0.01) increase in the number of sperms with abnormal morphology and decrease in epididymal sperm count, motility, plasma testosterone level and testicular cholesterol. Furthermore, HgCl2 exposure induced histopathological changes to the testis including morphological alterations of the seminiferous tubules, and degeneration and dissociation of spermatogenic cells. Notably, oral pretreatment of animals with Spirulina (300 mg/kg, bw) lowered the extent of the observed HgCl2-mediated toxicity, whereby significantly reducing the resulting lipid peroxidation products, mercury accumulation in the testis, histopathological changes of the testes and spermatozoal abnormalities. In parallel, the pretreatment with Spirulina also completely reverted the observed Hg-Cl2-induced inhibition in enzymatic activities of antioxidant biomarkers (SOD, CAT and GPx) back to control levels. The pretreatment of rats with S. platensis significantly recovered the observed HgCl2-mediated decrease in the weight of accessory sex organs. Taken together, our findings clearly highlight the role of S. platensis as a protective modulator of HgCl2-induced testicular injuries and suggest some therapeutic potential in mammals. Further investigation of therapeutic strategies employing Spirulina against heavy metals toxicity in humans is therefore warranted.

Phorate-induced oxidative stress, DNA damage and transcriptional activation of p53 and caspase genes in male Wistar rats

Male Wistar rats exposed to a systemic organophosphorus insecticide, phorate [O,O-diethyl S-[(ethylthio) methyl] phosphorothioate] at varying oral doses of 0.046, 0.092 or 0.184mg phorate/kg bw for 14days, exhibited substantial oxidative stress, cellular DNA damage and activation of apoptosis-related p53, caspase 3 and 9 genes. The histopathological changes including the pyknotic nuclei, inflammatory leukocyte infiltrations, renal necrosis, and cardiac myofiber degeneration were observed in the liver, kidney and heart tissues. Biochemical analysis of catalase and glutathione revealed significantly lesser activities of antioxidative enzymes and lipid peroxidation in tissues of phorate exposed rats. Furthermore, generation of intracellular reactive oxygen species and reduced mitochondrial membrane potential in bone marrow cells confirmed phorate-induced oxidative stress. Significant DNA damage was measured through comet assay in terms of the Olive tail moment in bone marrow cells of treated animals as compared to control. Cell cycle analysis also demonstrated the G(2)/M arrest and appearance of a distinctive SubG(1) peak, which signified induction of apoptosis. Up-regulation of tumor suppressor p53 and caspase 3 and 9 genes, determined by quantitative real-time PCR and enzyme-linked immunosorbent assay, elucidated the activation of intrinsic apoptotic pathways in response to cellular stress. Overall, the results suggest that phorate induces genetic alterations and cellular toxicity, which can adversely affect the normal cellular functioning in rats.

Protection of α-tocopherol and selenium against acute effects of malathion on liver and kidney of rats

Protection from effects of the organophosphate insecticide, malathion on the liver and kidney of male Wistar albino rats by α-tocopherol and selenium was investigated. Significantly greater (P<0.01 ) mean concentrations of malondialdehyde (MDA) and lesser concentrations (P<0.01) of reduced glutathione (GSH) and tissues total proteins were observed in liver and kidney of rats exposed to malathion. Activities of the antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were less in livers and kidneys of rats exposed to malathion. These effects caused by exposure to malathion were reversed when rats were subsequently treated orally with 100 mg/kg b.w. tocopherol and/or 0.1 mg selenium/kg b.w. Both tocopherol and selenium (Se) reduced the concentration of MDA, and increased concentration of total proteins and reduced glutathione and mean activities of SOD, CAT and GPx, to levels that were not significantly different from unexposed, control rats, previous to exposure to malathion. Selenium was significantly ( P<0.05) more effective at recovering activities of SOD and GPx in liver and kidney of malathion treated rats than was αtocopherol, whereas, α-tocopherol was significantly ( P<0.05) more effective at recovering activities of CAT in liver and kidney than was Se. Both α-tocopherol and Se were effective in alleviating oxidative damage in liver and kidney of rats caused by malathion.

Activation tagging of ADR2 conveys a spreading lesion phenotype and resistance to biotrophic pathogens

An Arabidopsis PR1::luciferase (LUC) transgenic line was transformed with activation T-DNA tags and the resulting population screened for dominant gain-of-function mutants exhibiting constitutive LUC activity. LUC imaging identified activated disease resistance 2 (adr2), which exhibited slowly spreading lesions in the absence of pathogen challenge. Molecular, genetic and histochemical analysis was employed to characterize this mutant in detail. adr2 plants constitutively expressed defence-related and antioxidant genes. Moreover, this line accrued increased quantities of salicylic acid (SA) and exhibited heightened mitogen-activated protein kinase activity. adr2 plants exhibited increased resistance against numerous biotrophic but not necrotrophic pathogens. The adr2 phenotype resulted from the overexpression of a Toll interleukin receptor (TIR) nucleotide binding site (NBS) leucine rich repeat (LRR) gene (At1g56510). Constitutive PR1 expression was completely abolished in adr2 nahG, adr2 npr1 and adr2 eds1 double mutants. Furthermore, heightened resistance against Hyaloperonospora arabidopsis Noco2 was compromised in adr2 nahG and adr2 eds1 double mutants but not in adr2 npr1, adr2 coi1 or adr2 etr1 plants. These data imply that adr2-mediated resistance operates through an Enhanced Disease Susceptibility (EDS) and SA-dependent defence signalling network which functions independently from COI1 or ETR1.

Transformation of Fusarium oxysporum by particle bombardment and characterisation of the resulting transformants expressing a GFP transgene

Fusarium is the causative agent of a variety of economically significant vascular wilt diseases of vegetables, flowers and field crops. The completion of the first Fusarium genome and the availability of an EST database now provides a platform for both forward and reverse genetic approaches to ascribe gene function in this phytopathogen. To underpin these strategies effective gene transfer procedures will be required. Here we describe an efficient and robust procedure for Fusarium oxysporum transformation based on particle bombardment. We utilised this procedure to introduce a chimeric gene comprised of the Aspergillus nidulans Pgdp promoter fused to a GFP reporter gene. A transformation efficiency of 45 transformants per μg of plasmid DNA was routinely achieved. The Pgdp promoter directed strong cytoplasmic expression of the GFP marker in transformed F. oxysporum monitored via fluorescence and confocal microscopy. A pathogenicity assay undertaken on Arabidopsis seedlings with selected transformants revealed that virulence was retained following transformation. Moreover, in a similar fashion to wild-type F. oxysporum, these transformants activated three distinct Arabidopsis defence gene promoter::luciferase fusions, which defined specific defence gene subsets.

From inflammation to gastric cancer: Role of Helicobacter pylori (Review)

Gastric cancer is a multifactorial disease and a leading cause of mortality and the risk factors for this include environmental factors and factors that influence host-pathogen interaction and complex interplay between these factors. Gastric adenocarcinomas are of two types, namely intestinal and diffuse type, and Helicobacter pylori (H. pylori) infection has been suspected of being causally linked to the initiation of chronic active gastritis, which leads to adenocarcinoma of the intestinal type. Even though most individuals with H. pylori infection do not show any clinical symptoms, long-term infection leads to inflammation of gastric epithelium and approximately 10% of infected patients develop peptic ulcers and 1–3% of patients develop gastric adenocarcinoma. Among the several mechanisms involved in tumorigenesis, CagA and peptidoglycan of H. pylori, which enter the infected gastric epithelial cells play an important role by triggering oncogenic pathways. Inflammation induced by H. pylori in gastric epithelium, which involves the cyclooxygenase-2/prostaglandin E2 pathway and IL-1β, is also an important factor that triggers chronic active gastritis and adenocarcinoma. H. pylori infection induced oxidative stress and dysregulated E-cadherin/β-catenin/p120 interactions and function also play a critical role in tumorigenesis. Environmental and dietary factors, in particular salt intake, are known to modify the pathogenesis induced by H. pylori. Gastric cancer induced by H. pylori appears to involve several mechanisms, making this mode of tumorigenesis a highly complicated process. Nevertheless, there are many events in this tumorigenesis that remain to be clarified and investigated.

Nitric oxide triggers specific and dose-dependent cytosolic calcium transients in Arabidopsis

Calcium (Ca2+) transients have been shown to take place in response to diverse developmental and physiological cues. Also, it is involved in biotic and abiotic stress signaling. Nitric oxide (NO) is an important signaling molecule that plays a crucial role in plant growth and development, starting from germination to flowering, ripening of fruit and senescence of organs. Moreover, it plays a pivotal role in several biotic and abiotic stress signaling processes. In the present work, the ability of NO to trigger increases in cytosolic calcium concentration ([Ca2+]cyt) was investigated. For this purpose, transgenic Arabidopsis seedlings constitutively expressing the luminescent Ca2+-sensitive protein apoaequorin (35S::APOAEQUORIN) was employed. In chemiluminescence and in vivo Ca2+ imaging assays, the NO-donor sodium nitroprusside (SNP) brought about a strong, instantaneous, reproducible, and dose-dependent rise in [Ca2+]cyt. Moreover, the observed rise in [Ca2+]cyt was shown to be NO-specific and not associated with decomposition products of SNP, as the NO-scavenger 2-4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3 oxide (C-PTIO) significantly blunted the observed NO-mediated spike in [Ca2+]cyt. Interestingly, preincubation of 35S::APOAEQUORIN Arabidopsis seedlings with the plasma membrane channel blocker lanthanum chloride resulted in partial concentration-dependent blocking of the NO-specific Ca2+ transient. This observation indicates that, in addition to the mobilization of [Ca2+]cyt, as an external source in response to NO treatment, an appreciable contribution of yet unidentified internal pools also exist.

A54T polymorphism in the fatty acid binding protein 2 studies in a Saudi population with type 2 diabetes mellitus

BackgroundFatty acid-binding protein 2 (FABP2) is an intracellular protein expressed exclusively in the enterocytes of proximal small intestine. FABP2 has a high affinity for saturated and unsaturated long-chain fatty acids and is believed to be involved in the absorption and transport of dietary fatty acids.MethodsThis is a case–control study conceded in 438 T2DM cases and 460 subjects with normal glucose levels and non-obese considered as healthy controls. Allelic discrimination was performed using TaqMan single-nucleotide polymorphism was carried out by real time-polymerase chain reaction (RT-PCR) assays using purified DNA.ResultsClinical data and anthropometric measurements except age, glucose levels and lipid profile of the patients were significantly different from those of the controls (p < 0.05). Statistical analyses failed to show any type of significant association of the polymorphism between cases and controls. However logistic regression analyses was suggests that the TT genotype is significantly associated with male patients (p = 0.001). None of the allele or genotypes of FABP2 A54T was associated with T2DM cases versus the controls (AT genotype, OR = 0.85 (0.64-1.12), p = 0.25; TT genotype, OR = 0.66 (0.39-1.11), p = 0.11; T allele, 0.82 (0.67-1.02), p = 0.08).ConclusionIn conclusion, this study suggests that the above named variant in FABP2 gene is not potential contributor to the risk of T2DM and related traits in a Saudi population. However TT genotype is a risk factor for the disease in males.

Mosquito vectors survey in the AL-Ahsaa district of eastern Saudi Arabia

Abstract The present study aimed to identify the mosquito vectors distributed throughout AL-Ahsaa district situated in the eastern region of Saudi Arabia. Mosquito larvae were collected seasonally for one year (October 2009 to September 2010) from different breeding sites in seven rural areas utilizing long aquatic nets. Salinity and pH of these breeding sites were also measured seasonally. The survey revealed the presence of five mosquito species, Aedes caspius Pallas (Diptera: Culicidae), Anopheles multicolor Cambouliu, Culex perexiguus Theobald, Culex pipiens L., and Culex pusillus Macquart, representing three genera; four of them (Ae. caspius, An. multicolor, Cx. perexiguus, and Cx. pipiens) are important vectors of diseases. Ae. caspius is the most common vector followed by Cx. pipiens and then Cx. perexiguus. Mosquitoes in AL-Ahsaa are prevalent in both winter and spring seasons, rarely encountered in summer, and are found in moderation during the autumn months. These results are compared with results of other regions in the Kingdom of Saudi Arabia.