Qazi Mohd. Rizwanul Haq

Dietary Flavonoid Quercetin and Associated Health Benefits—An Overview

Phytochemicals have received a considerable attention in the present day world. Epidemiological studies have established that phytochemicals contribute more qualitatively to the total antioxidant activity of foods than nutrient antioxidants like vitamin C and vitamin E. Among polyphenols, quercetin constitutes the main flavonoid in our daily diet being particularly abundant in onions and apples. Since the realization that many folk medicines in use contain flavonoids, interest in this class of compounds has intensified. Quercetin acts as a strong reducing agent, which together with other dietary reductants such as vitamin C, vitamin E, and carotenoids protect body tissue against oxidative stress. Recent reports suggest that quercetin as antioxidant improves normal cell survival and as pro-oxidant induces apoptosis in cancerous cells whereby prevents tumor proliferation. Among other important properties like modulation of genes related to cell cycle, signal transduction, and xenobiotic metabolism, quercetin has also been attributed with antiviral, anti-inflammatory, antibacterial, and muscle-relaxing properties. In the literature, only a few in vivo studies have been carried out; therefore, before making any authentic health claim about this compound, it is essential to know its nature and its dietary origin. Furthermore, it is important to know the amount present in different diets and its bioavailability, followed by clinical trials and investigations, if researchers are to use it as an chemo-preventive and chemotherapeutic agent against various deleterious degenerative diseases.

Heavy Metals and Human Health: Mechanistic Insight into Toxicity and Counter Defense System of Antioxidants

Heavy metals, which have widespread environmental distribution and originate from natural and anthropogenic sources, are common environmental pollutants. In recent decades, their contamination has increased dramatically because of continuous discharge in sewage and untreated industrial effluents. Because they are non-degradable, they persist in the environment; accordingly, they have received a great deal of attention owing to their potential health and environmental risks. Although the toxic effects of metals depend on the forms and routes of exposure, interruptions of intracellular homeostasis include damage to lipids, proteins, enzymes and DNA via the production of free radicals. Following exposure to heavy metals, their metabolism and subsequent excretion from the body depends on the presence of antioxidants (glutathione, α-tocopherol, ascorbate, etc.) associated with the quenching of free radicals by suspending the activity of enzymes (catalase, peroxidase, and superoxide dismutase). Therefore, this review was written to provide a deep understanding of the mechanisms involved in eliciting their toxicity in order to highlight the necessity for development of strategies to decrease exposure to these metals, as well as to identify substances that contribute significantly to overcome their hazardous effects within the body of living organisms.

Glutathione as an antioxidant in inorganic mercury induced nephrotoxicity

Heavy metal toxicity represents an uncommon but clinically significant medical condition, which if unrecognized or inappropriately treated results in significant morbidity and mortality. Among heavy metals, mercury is recognized as a potent and widely distributed toxicant having the ability to accumulate at various levels of food chain besides possessing ability to cross placental and blood-brain barrier. Symptom picture of mercury (Hg 2+ ) toxicity is characterized mainly by a series of renal disorders. Mechanism of inorganic mercury toxicity includes production of reactive oxygen species (ROS) capable of damaging lipids in membrane, proteins or enzymes in tissues, and DNA to induce oxidative stress as balance between generation, and elimination of ROS is essential for maintaining the functional integrity of a cell. Mitigation of endogenous mercury depends as a part on the presence of antioxidants such as glutathione - most abundant intracellular non-protein thiol that plays a central role in the maintenance of cellular redox status by quenching free radicals generated during oxidative stress. Ability of a cell to survive the threat posed by endogenous mercury represents a biological adaptation fundamental to survival. This review describes the current understanding and the mechanisms involved by different forms of mercury in eliciting their toxicity in kidney along with the knowledge of major intracellular reductant that plays important role in the mitigation of mercury toxicity for the maintenance of homeostasis within the body of living organisms.

In silico analysis reveals that several tomato microRNA/microRNA * sequences exhibit propensity to bind to tomato leaf curl virus (ToLCV) associated genomes and most of their encoded open reading frames (ORFs)

Tomato leaf curl virus (ToLCV) is a member of family geminiviridae that constitute rapidly emerging group of phytopathogens posing threat to a large number of vegetable crops worldwide. Three different genomes are found to be associated with ToLCV viz., DNA-A, DNA-B and beta satellite DNA. MicroRNAs (miRs) are known to govern several fundamental processes in eukaryotes, including basal defense mechanisms. In animals, it has been demonstrated that certain host miRs prevent viral establishment by directly interfering with pathogen replication or by binding to viral transcripts. However, in spite of the existence of huge families of phytopathogenic viruses, no such mechanism has been observed in plants. In the present study, we performed in silico analysis to investigate whether tomato encoded miR/miR* sequences possess any potential to bind to viral genome and/or encoded ORFs. We observed that different sequences can bind to ToLCNDV DNA-A, ToLCNDV DNA-B and ToLCNDV associated DNA beta genomes and most of the encoded ORFs. Interestingly, our analysis revealed that several miR* species could similarly target genome and ORFs of ToLCNDV suggesting novel role of miR* in host defense response. This observation holds much importance as miR* molecules are presently thought to follow degradation pathway and are not assigned with any function. Moreover, we could predict targets for these miR* sequences that are generally involved in plant metabolism. Overall, these results shed light on new paradigm of intricate host-pathogen interactions via miRNA pathway.

Novel approaches of beneficial Pseudomonas in mitigation of plant diseases – an appraisal

Control of plant diseases has always remained a challenge as diseases affecting plant health are a major and chronic threat not only to food production, but also to ecosystem stability worldwide. As agricultural production intensified over the past three decades, producers became dependent on agrochemicals as a relatively reliable method of crop protection. However, growing concerns regarding continued use of agrochemicals, posing adverse effects on human health besides posing the threat of environmental deterioration, has driven search for novel environment friendly methods to control plant diseases that in turn can contribute to the goal of sustainability in agriculture. Mitigation of plant diseases by naturally inhabiting antagonistic micro-organisms such as plant growth-promoting rhizobacteria has gained much importance as biocontrol agents seem to be the best possible measures for saving plants from phytopathogenic organisms without causing any harmful effect to mankind as well as to the environment. Mechanisms of microbial antagonism toward phytopathogenic organisms include competition for nutrients and space, production of siderophores, hydrogen cyanide, antibiotics, and/or production of fungal cell wall-degrading lytic enzymes. The present review is aimed at exploring benefits of natural alternatives for agrochemicals along with the study of their antagonistic mechanisms that makes them a novel substitute to agrochemicals.

Molecular Markers Detect Redundancy and Miss-identity in Genetic Stocks with Alien Leaf Rust Resistance Genes Lr32 and Lr28 in Bread Wheat

Ten elite near-isogenic line (NIL) pairs of bread wheat (Triticum aestivum L em Thell) each carrying one of the two alien leaf rust resistance (Lr) genes Lr32 and Lr28, derived from Triticum tauschii and Triticum speltoides, respectively were tested for disease phenotype in controlled conditions. The disease phenotype of the NIL pair detected distinction between the Lr32 donor parent and its derivatives in ten cultivar backgrounds documented as carrying the gene Lr32. The RAPD and SCAR molecular markers identified earlier as linked to Lr32 amplified the critical marker bands identically in eight of the ten NIL pairs as well as the Lr28 donor parent. The critical bands were not amplified in the Lr32 donor parent. A Triticum speltoides specific microsatellite null allele marker located on chromosome 4AL, the genomic region associated with Lr28, expressed in an identical polymorphism as the RAPD and SCAR markers. The PCR product sequenced from a NIL pair revealed 100% homology. It is confirmed that eight of the ten elite Lr32 lines carry the gene Lr28. Molecular marker tools need to be employed to eliminate such miss-identities and reduce redundancy in Indian elite germplasm stocks of wheat possessing the alien Lr genes.

Plant abiotic stress: deciphering remedial strategies for emerging problem

Growing in their natural environment, plants often encounter unfavorable environmental conditions that interrupt normal plant growth and productivity. Drought, high/low temperature and saline soils are the most common abiotic stresses that plants encounter in their natural environments. Molecular and genomic analyses have facilitated gene discovery and enabled genetic engineering using several functional or regulatory genes that are known to be involved in stress response and preliminary tolerance, to activate specific or broad pathways related to abiotic stress tolerance in plants. Through the use of transgenic technology, goals such as production of plants with desired traits that were unattainable with traditional selection programs are achieved. This review deals with recent advancement in understanding the role of various stress responsive genes and their critical importance for explaining the control mechanism of abiotic stress tolerance and engineering stress tolerant crops based on the expression of specific stress related genes.

Characterization, Genetic Diversity, and Evolutionary Link of Cucumber mosaic virus Strain New Delhi from India

The genome of Cucumber mosaic virus New Delhi strain (CMV-ND) from India, obtained from tomato, was completely sequenced and compared with full genome sequences of 14 known CMV strains from subgroups I and II, for their genetic diversity. Sequence analysis suggests CMV-ND shares maximum sequence identity at the nucleotide level with a CMV strain from Taiwan. Among all 15 strains of CMV, the encoded protein 2b is least conserved, whereas the coat protein (CP) is most conserved. Sequence identity values and phylogram results indicate that CMV-ND belongs to subgroup I. Based on the recombination detection program result, it appears that CMV is prone to recombination, and different RNA components of CMV-ND have evolved differently. Recombinational analysis of all 15 CMV strains detected maximum recombination breakpoints in RNA2; CP showed the least recombination sites.

Prospects for Exploiting Bacteria for Bioremediation of Metal Pollution

Metals being recalcitrant to biodegradation process pose a persistent threat to human health and environment. In view of increase in discharge along with improper management of persistent metal pollutants, it is imperative to develop cost-effective and efficient methods for their remediation. As contamination of soil and water has threatened the well being of humans and natural environment, microorganisms play crucial role in combating the widespread pollution of global environment. Clusters of genes coding for catabolic transformation facilitate their detoxification from the environment. Development of effective tools to facilitate environmental cleanup of metal pollutants beyond genetic confines of natural host has resulted in the expressional enhancement of promiscuous enzymes, involved in the transformation of metal compounds. A thorough understanding of microbes that express heterologous proteins for metal transformation would result in economic production and as such its application in bioremediation process. This review summarizes fundamental insights regarding metals in relation to oxidative stress, insights on metal binding proteins/peptides for immobilization, information regarding genetic engineering for enzymes involved in metal transformation, and strategies that can be employed to overcome the bottlenecks associated with microbial based remediation strategies.

Nanostructured coordination complexes/polymers derived from cardanol: “one-pot, two-step” solventless synthesis and characterization

Growing interests in the development of advanced functional materials from renewable resources due to the depleting petroleum resources, increasing costs, and associated hazards reflect global requirement for increased sustainability. Cardanol [Col] is an agro by-product of the cashew nut industry. It is cost effective, nontoxic, biodegradable and an abundantly available renewable resource. In the present study, we report the development of nanostructured coordination polymer [CP] self-standing transparent films from Col (as an organic linker or bridging-ligand) and Mn(II) ‘d5’ and Co(II) ‘d7’ divalent metal ions (as metal nodes) by a solid-state in situ method. The resulting CP films showed nanoporous morphology, amorphous behaviour, good thermal stability up to 260–300 °C, moderate antibacterial activity against Staphylococcus aureus (MTCC 902), Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa (MTCC 2453) and also good anti-biofilm activity.