Showing papers by "Iqbal Ahmad published in 2011"
TL;DR: Cinnamaldehyde showed the most promising antifungal activity and killing potency against Aspergillus fumigatus MTCC2550 and Trichophyton rubrum IOA-9 and itraconazole, and showed strongest synergy with fluconazole against A. fumIGatus and T. rubrum.
Abstract: The aim of this study was to screen certain plant essential oils and active compounds for antifungal activity and their in vitro interaction with fluconazole against drug-resistant pathogenic fungi. The methods employed in this work included disc diffusion, broth macrodilution, time kill methods and checkerboard microtiter tests. Oil compositions were evaluated by gas chromatography-mass spectrometry (GC-MS) analysis. Transmission electron microscopy was used to assess the effect of essential oils on cellular structures of test fungi. Test fungal strains exhibited resistance to at least two drugs (fluconazole and itraconazole). Among the 21 essential oils or active compounds tested, ten showed promising antifungal activity. GC-MS analysis revealed the presence of major active compounds in the essential oils used. Cinnamaldehyde showed the most promising antifungal activity and killing potency against Aspergillus fumigatus MTCC2550 and Trichophyton rubrum IOA-9. Cinnamaldehyde showed strongest synergy with fluconazole against A. fumigatus and T. rubrum by reducing the minimum inhibitory concentration of fluconazole up to 8-fold. Zones of lysis of the cell wall and cell membrane appeared to be where cinnamaldehyde acted on fungi. This study highlights the broad spectrum antifungal activity of essential oils and active compounds and their synergy with fluconazole against drug-resistant fungi.
103 citations
TL;DR: These findings highlight anti-elastase and anti-keratinase activity of above mentioned essential oils as a novel property to be exploited in controlling invasive and superficial mycoses.
99 citations
01 Jan 2011
TL;DR: Recent developments in techniques for studying rhizobacterial communities and detection and tracking systems of inoculated bacteria are important in future application and assessment of effectiveness and consistent performance of microbial inoculants in crop production and protection.
Abstract: Roots serve a multitude of functions in plants including anchorage, acquisition of nutrients and water, and production of exudates with growth regulatory properties. The root–soil interface, or rhizosphere, is the site of greatest biological and chemical activity within the soil matrix. Plant growth-promoting rhizobacteria (PGPR) are known to influence plant health by controlling plant pathogens or via direct enhancement of plant development in the laboratory and in greenhouse experiments. Unfortunately, however, results in the field have been less consistent. The colonization of roots by inoculated bacteria is an important step in the interaction between beneficial bacteria and the host plant. However, colonization is a complex phenomenon influenced by many biotic and abiotic parameters, some of which are only now apparent. Monitoring fate and metabolic activity of microbial inoculants as well as their impact on rhizosphere and soil microbial communities are needed to guarantee safe and reliable application, independent of whether they are genetically modified or not. The first and most crucial prerequisite for effective use of PGPRs is that strain identity and activity are continuously confirmed. A combination of both classical and molecular techniques must be perfected for more effective monitoring of inoculants strain (both genetically modified and unmodified) after release into the soil. Recent developments in techniques for studying rhizobacterial communities and detection and tracking systems of inoculated bacteria are important in future application and assessment of effectiveness and consistent performance of microbial inoculants in crop production and protection.
41 citations
TL;DR: This study seems to provide some novel antimicrobial leads with strong antioxidant potential and the associated ability of antimutagenicity, as four compounds evaluated for their antimUTagenic activity against the directly acting mutagens, methyl methanesulfonate and sodium azide, in Salmonella typhimurium strains showed no sign of mutagenicity.
Abstract: Multidrug resistance (MDR) in microorganisms is a cause of major concern for clinicians and pharmaceutical industries. Continuous development of new antimicrobial drugs with multiple targets and potentials is expected to efficiently combat MDR in these microorganisms. In a continued exploration of new antimicrobial drug leads, 11 marine natural products, semisynthetic, or related synthetic analogs (1-11) and two tobacco cembranoids (12 and 13) were screened for their antimicrobial, antioxidant, and antimutagenic activities. Eight compounds showed varying levels of both antibacterial and antifungal activities. Compounds such as 17-O-methyllatrunculin-A, verongiaquinol, (1S,2E,4R,6R,7E,11E)-2,7,11-cembratriene-4,6-diol), and manzamine-A showed a broad spectrum of activity, inhibiting six of seven tested bacteria with zone of inhibition diameter from 9 to 30 mm. Four of these active compounds also showed antifungal activity. The findings of the in vitro time-kill assay of the most active compound, verongiaquinol, against Staphylococcus aureus indicated its subinhibitory effect at the level lower than the minimal inhibitory concentration (MIC) values (i.e., 2 and 4 µg/mL). At the MIC (8 µg/mL), bacterial cells were completely killed within 18 hours of incubation. DPPH free radical scavenging activity was demonstrated by five compounds in the range of 89.65-36.19% decolorization. Further, four compounds evaluated for their antimutagenic activity against the directly acting mutagens, methyl methanesulfonate and sodium azide, in Salmonella typhimurium strains, interestingly, showed no sign of mutagenicity. Verongiaquinol and manzamine A, in fact, reduced the mutagenicity by 50-75% at a dose of 5 µg/plate in different test strains. Our study seems to provide some novel antimicrobial leads with strong antioxidant potential and the associated ability of antimutagenicity.
37 citations
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TL;DR: In this article, the authors investigated the relationship of employees' work-life conflict with their performance and found that the Pearson's product moment correlation showed no association for the said relationship.
Abstract: With the ever increasing requirements of the work, employees are likely to develop conflict between their work and non-work activities. This paper investigates the relationship of employees’ work-life conflict with their performance. A convenient sample of 103 respondents came from National Database and Registration Authority (NADRA) for the study. The Pearson’s product moment correlation showed no association for the said relationship. An inverse relationship was found working between age of the employees and work-life conflict they experience. Moreover differences of work-life conflict and performance for some demographic variables were measured by applying independent sample t test. The results of the study are compared to the available relevant studies.
21 citations
01 Jan 2011
TL;DR: In this paper, the authors provide an overview of recent trends in microbial exploitation in plant growth promotion and sustainable environment mainly through bioremediation, biodegradation, and biosorption processes.
Abstract: Microbial diversity is an important component of the overall global biological diversity Recent technological advances in exploring microbial diversity have revealed that a large proportion of microorganisms are still undiscovered, and their ecological roles are largely unknown Careful selection of microbes and intelligent design of test assays are the key steps in developing new technologies for effective utilization of microorganisms for sustainable agriculture, environmental protection, and human and animal health Several microbial applications are widely known in solving major agricultural (ie, crop productivity, plant health protection, and soil health maintenance) and environmental issues (ie, bioremediation of soil and water from organic and inorganic pollutants) Wastewater treatment and recycling of agricultural and industrial wastes are other important uses of microbial technology It is expected that microbes in combination with developments in electronics, software, digital imaging, and nanotechnology will play a significant role in solving global problems of the twenty-first century, including climate change These advances are expected to enhance sustainability of agriculture and the environment This chapter provides an overview of recent trends in microbial exploitation in plant growth promotion and sustainable environment mainly through bioremediation, biodegradation, and biosorption processes Recent uses and application of microbes such as biosensors, synthesis of nanomaterials, and probiotics are also discussed
21 citations
TL;DR: A series of novel chromone derivatives have been synthesized employing 3-formylchromones and 5-acetyl-1,3-dimethylbarbituric acid as starting materials both under conventional heating method and microwave irradiation technique in good yields as discussed by the authors.
Abstract: A series of novel chromone derivatives have been synthesized employing 3-formylchromones and 5-acetyl-1,3-dimethylbarbituric acid as starting materials both under conventional heating method and microwave irradiation technique in good yields. The synthesized compounds were screened in vitro antibacterial activity against the representative panel of two Gram-positive bacteria and two Gram-negative bacteria. The synthesized compounds were also tested for their inhibitory action against three strains of fungus. The various compounds show potent inhibitory action against test organisms.
17 citations
TL;DR: In this paper, the authors investigated the relationship of employees' work-life conflict with their performance and found that the Pearson's product moment correlation showed no association for the said relationship.
Abstract: With the ever increasing requirements of the work, employees are likely to develop conflict between their work and non-work activities. This paper investigates the relationship of employees’ work-life conflict with their performance. A convenient sample of 103 respondents came from National Database and Registration Authority (NADRA) for the study. The Pearson’s product moment correlation showed no association for the said relationship. An inverse relationship was found working between age of the employees and work-life conflict they experience. Moreover differences of work-life conflict and performance for some demographic variables were measured by applying independent sample t test. The results of the study are compared to the available relevant studies.
14 citations
01 Jan 2011
TL;DR: This chapter addresses the interactions of heavy metals with organisms for application in wastewater or soil treatment systems, with special emphasis on yeasts and fungi, and the biosorption abilities of fungal biomass toward metal ions are emphasized.
Abstract: Heavy metals pose a significant ecological and public health hazard because of their toxic effects and their ability to accumulate in terrestrial and aquatic food chains. This chapter addresses the interactions of heavy metals with organisms for application in wastewater or soil treatment systems, with special emphasis on yeasts and fungi. Conventional techniques to remove metals from wastewaters have several disadvantages; however, biosorption has demonstrated significant metal removal performance from large volumes of effluents. One key step of treatment processes for cleanup of heavy metal-enriched water or soil involves growing resistant cells that accumulate metals to optimize removal through a combination of biosorption and continuous metabolic uptake. Fungal biosorption can be used for the removal of metals from contaminated water and soil; fungal biosorbents are less expensive and more effective alternatives for the removal of metallic elements, especially heavy metals, from aqueous solution. In this chapter, the biosorption abilities of fungal biomass toward metal ions are emphasized. The chapter also highlights the mechanisms involved in fungal biosorption and the factors affecting the biosorption process. The current status and achievements of fungal biosorption technologies are reviewed.
9 citations
01 Jan 2011
TL;DR: This chapter provides an updated overview on bacterial QS, assays and methods for detecting signal molecules, and various approaches to inhibit AHL-based quorum sensing, and importance of QS interference by prokaryotic and eukaryotic organisms in relation to plant health and the environment is discussed.
Abstract: Bacteria use the language of low-molecular-weight ligands to assess their population densities in a process called quorum sensing (QS). Different types of quorum sensing pathways are present in Gram-negative and Gram-positive bacteria. Signal molecules most commonly used in Gram-negative bacteria are acyl homoserine lactones. In recent years, a substantial amount of literature and data have been available on bacterial QS. Recently, interest in modulation of quorum sensing with different approaches has increased among scientific communities. In this chapter, we provide an updated overview on bacterial QS, assays and methods for detecting signal molecules, and various approaches to inhibit AHL-based quorum sensing. Significance of QS interference by prokaryotic and eukaryotic organisms in relation to plant health and the environment is discussed here.
01 Jan 2011
TL;DR: A brief overview of the molecular detection methods applicable to microbes from food and their applications in the area of bacterial pathogens in the last 3 decades is reported.
Abstract: Conventional methods of pathogen identification have often depended on the identification of disease symptoms, isolation, and culturing of the organisms, and identification by morphology and biochemical tests. The major limitations of these culture-based morphological approaches, however, are the reliance on the ability of the organism to be cultured, the time-consuming nature, and requirement of extensive taxonomic expertise. The use of molecular methods can circumvent many of these shortcomings. Accordingly, there have been significant developments in the area of molecular detection of bacterial pathogens in the last 3 decades. We report here a brief overview of the molecular detection methods applicable to microbes from food.