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Dive into the research topics where Gulshan Singh is active.

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Featured researches published by Gulshan Singh.


Journal of Photochemistry and Photobiology B-biology | 2016

Biosynthesis of ZnO nanoparticles using Jacaranda mimosifolia flowers extract: Synergistic antibacterial activity and molecular simulated facet specific adsorption studies.

Deepali Sharma; Myalowenkosi I. Sabela; Suvardhan Kanchi; Phumlane S. Mdluli; Gulshan Singh; Thor Axel Stenström; Krishna Bisetty

The naturally occurring biomolecules present in the plant extracts have been identified to play an active role in the single step formation of nanoparticles with varied morphologies and sizes which is greener and environmentally benign. In the present work, spherical zinc oxide nanoparticles (ZnO NPs) of 2-4nm size were synthesized using aqueous extract of fallen Jacaranda mimosifolia flowers (JMFs), treated as waste. The microwave assisted synthesis was completed successfully within 5min. Thereafter, phase identification, morphology and optical band gap of the synthesized ZnO NPs were done using X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and UV-Visible spectroscopy techniques. The composition of JMFs extract was analyzed by gas chromatography-mass spectrometry (GC-MS) and the ZnO NPs confirmation was further explored with fourier transform infrared spectroscopy (FTIR). The GC-MS results confirmed the presence of oleic acid which has high propensity of acting as a reducing and capping agent. The UV-Visible data suggested an optical band gap of 4.03eV for ZnO NPs indicating their small size due to quantum confinement. Further, facet specific adsorption of oleic acid on the surface of ZnO NPs was studied computationally to find out the impact of biomolecules in defining the shape and size of NPs. The viability of gram negative Escherichia coli and gram positive Enterococcus faecium bacteria was found to be 48% and 43%, respectively at high concentration of NPs.


Acta Tropica | 2017

Detection and quantification of soil-transmitted helminths in environmental samples: A review of current state-of-the-art and future perspectives

Isaac Dennis Amoah; Gulshan Singh; Thor Axel Stenström; Poovendhree Reddy

It is estimated that over a billion people are infected with soil-transmitted helminths (STHs) globally with majority occurring in tropical and subtropical regions of the world. The roundworm (Ascaris lumbricoides), whipworm (Trichuris trichiura), and hookworms (Ancylostoma duodenale and Necator americanus) are the main species infecting people. These infections are mostly gained through exposure to faecally contaminated water, soil or contaminated food and with an increase in the risk of infections due to wastewater and sludge reuse in agriculture. Different methods have been developed for the detection and quantification of STHs eggs in environmental samples. However, there is a lack of a universally accepted technique which creates a challenge for comparative assessments of helminths egg concentrations both in different samples matrices as well as between locations. This review presents a comparison of reported methodologies for the detection of STHs eggs, an assessment of the relative performance of available detection methods and a discussion of new emerging techniques that could be applied for detection and quantification. It is based on a literature search using PubMed and Science Direct considering all geographical locations. Original research articles were selected based on their methodology and results sections. Methods reported in these articles were grouped into conventional, molecular and emerging techniques, the main steps in each method were then compared and discussed. The inclusion of a dissociation step aimed at detaching helminth eggs from particulate matter was found to improve the recovery of eggs. Additionally the selection and application of flotation solutions that take into account the relative densities of the eggs of different species of STHs also results in higher egg recovery. Generally the use of conventional methods was shown to be laborious and time consuming and prone to human error. The alternate use of nucleic acid-based techniques has improved the sensitivity of detection and made species specific identification possible. However, these nucleic acid based methods are expensive and less suitable in regions with limited resources and skill. The loop mediated isothermal amplification method shows promise for application in these settings due to its simplicity and use of basic equipment. In addition, the development of imaging soft-ware for the detection and quantification of STHs shows promise to further reduce human error associated with the analysis of environmental samples. It may be concluded that there is a need to comparatively assess the performance of different methods to determine their applicability in different settings as well as for use with different sample matrices (wastewater, sludge, compost, soil, vegetables etc.).


Molecules | 2016

Antibiotic Resistant Superbugs: Assessment of the Interrelationship of Occurrence in Clinical Settings and Environmental Niches

Anthony A. Adegoke; Adekunle Christopher Faleye; Gulshan Singh; Thor Axel Stenström

The increasing threat to global health posed by antibiotic resistance remains of serious concern. Human health remains at higher risk due to several reported therapeutic failures to many life threatening drug resistant microbial infections. The resultant effects have been prolonged hospital stay, higher cost of alternative therapy, increased mortality, etc. This opinionated review considers the two main concerns in integrated human health risk assessment (i.e., residual antibiotics and antibiotic resistant genes) in various compartments of human environment, as well as clinical dynamics associated with the development and transfer of antibiotic resistance (AR). Contributions of quorum sensing, biofilms, enzyme production, and small colony variants in bacteria, among other factors in soil, water, animal farm and clinical settings were also considered. Every potential factor in environmental and clinical settings that brings about AR needs to be identified for the summative effects in overall resistance. There is a need to embrace coordinated multi-locational approaches and interrelationships to track the emergence of resistance in different niches in soil and water versus the hospital environment. The further integration with advocacy, legislation, enforcement, technological innovations and further research input and recourse to WHO guidelines on antibiotic policy would be advantageous towards addressing the emergence of antibiotic resistant superbugs.


Journal of Hazardous Materials | 2016

Exploring the potential reservoirs of non specific TEM beta lactamase (blaTEM) gene in the Indo-Gangetic region: A risk assessment approach to predict health hazards

Gulshan Singh; Poornima Vajpayee; Neetika Rani; Isaac Dennis Amoah; Thor Axel Stenström; Rishi Shanker

The emergence of antimicrobial resistant bacteria is an important public health and environmental contamination issue. Antimicrobials of β-lactam group accounts for approximately two thirds, by weight, of all antimicrobials administered to humans due to high clinical efficacy and low toxicity. This study explores β-lactam resistance determinant gene (blaTEM) as emerging contaminant in Indo-Gangetic region using qPCR in molecular beacon format. Quantitative Microbial Risk Assessment (QMRA) approach was adopted to predict risk to human health associated with consumption/exposure of surface water, potable water and street foods contaminated with bacteria having blaTEM gene. It was observed that surface water and sediments of the river Ganga and Gomti showed high numbers of blaTEM gene copies and varied significantly (p<0.05) among the sampling locations. The potable water collected from drinking water facility and clinical settings exhibit significant number of blaTEM gene copies (13±0.44-10200±316 gene copies/100mL). It was observed that E.crassipes among aquatic flora encountered in both the rivers had high load of blaTEM gene copies. The information on prevalence of environmental reservoirs of blaTEM gene containing bacteria in Indo-Gangetic region and risk associated will be useful for formulating strategies to protect public from menace of clinical risks linked with antimicrobial resistant bacteria.


Journal of Water and Health | 2017

Comparison of droplet digital PCR and quantitative PCR for the detection of Salmonella and its application for river sediments

Gulshan Singh; Ayanda Sithebe; Abimbola Motunrayo Enitan; Sheena Kumari; Faizal Bux; Thor Axel Stenström

Despite advances in microbial detection that quantitative polymerase chain reaction (qPCR) has led to, complex environmental samples, such as sediments, remain a challenge due to presence of PCR inhibitors. Aquatic sediments accumulate particle-bound microbial contaminants and thereby reflect a cumulative microbial load over time. The relatively new droplet digital PCR (ddPCR) has emerged as a direct quantitative method, highly tolerant to PCR inhibitors and relinquishing the necessity for calibration/standard curves. Information is virtually absent where ddPCR has been applied to detect pathogenic organisms in aquatic sediments. This study compared the efficacy of ddPCR with qPCR, for quantification of Salmonella in sediments from the Palmiet River near an informal settlement in Durban, South Africa. ddPCR significantly improved both analytical sensitivity and detection of low concentrations of Salmonella as compared to qPCR. The expected copy numbers measured from both qPCR and ddPCR showed good R2 values (0.999 and 0.994, respectively). The site mostly affected by the informal settlements exhibited Salmonella in the range of 255 ± 37 and 818 ± 30 Salmonella/g (p ≤ 0.0001) in qPCR and ddPCR, respectively. The improved detection of Salmonella in sediments with ddPCR makes it a promising technical method for the quantification of Salmonella in multifarious environmental samples.


Acta Tropica | 2018

Methods for the detection of Cryptosporidium and Giardia: From microscopy to nucleic acid based tools in clinical and environmental regimes

Folasade Adeyemo; Gulshan Singh; Poovendhree Reddy; Thor Axel Stenström

The detection and characterization of genotypes and sub genotypes of Cryptosporidium and Giardia is essential for their enumeration, surveillance, prevention, and control. Different diagnostic methods are available for the analysis of Cryptosporidium and Giardia including conventional phenotypic tools that face major limitations in the specific diagnosis of these protozoan parasites. The substantial advancement in the development of genetic signature based molecular tools for the quantification, diagnosis and genetic variation analysis has increased the understanding of the epidemiology and preventive measures of related infections. The conventional methods such as microscopy, antibody and enzyme based approaches, offer better detection results when combined with advanced molecular methods. Gene based approaches increase the precision of identification, for example, many signatures detected in environmental matrices represent species/genotype that are not infectious to humans. This review summarizes the available methods and the advantages and limitations of advance detection techniques like nucleic acid-based approaches for the detection of viable oocysts and cysts of Cryptosporidium and Giardia along with the conventional and widely accepted detection techniques like microscopy, antibody and enzyme based ones. This technical article also encourages the wide application of molecular methods in genetic characterization of distinct species of Cryptosporidium and Giardia, to adopt necessary preventive measures with reliable identification and mapping the source of contamination.


Archive | 2017

Biotechnological Intervention to Enhance the Potential Ability of Bioenergy Plants for Phytoremediation

Gulshan Singh; Poonam Singh; Abhishek Guldhe; Thor Axel Stenström; Faizal Bux; Sheena Kumari

Phytoremediation has emerged as an attractive idea for the utilization of plants and the microbial communities for the environmental cleanup. Despite of advances made in this research area, there are still blockades for its implication on a wide scale. These hurdles include limited metabolic rate of plants and failure to break down numerous complex compounds or to tolerate/accumulate heavy metals. The in-depth knowledge of the factors affecting contaminant’s translocation, volatilization, uptake, bioavailability and degradation is required, in order to increase the phytoremediation potential of bioenergy crops. The use of bioenergy crops has offered a viable option for phytoremediation that can aid to the energy supply and showed a pivotal role in meeting the targeted goals for the use of renewable energy sources. Moreover, genetic engineering has opened new avenues in this research area, by offering the chance for the direct gene transfer to enhance bioenergy crops/plant capabilities for environmental cleanup. The advanced “omics” methods will increase our understanding towards integrated activity patterns between plants and associated microorganism and harness it to the growth, structural organization of microbial communities, accumulation, tolerance and detoxification to increase phytoremediation capability of the plant. In this chapter, the mechanism of phytoremediation and new high-throughput biotechnological strategies adopted to enhance the ability of phytoremediation potential of bioenergy crops have been described with challenges harnessing plants in phytoremediation.


Chronic Obstructive Pulmonary Disease: Open Access | 2018

Acute Pancreatitis and Pulmonary Complications

Murli Manohar; Gulshan Singh

Citation: Manohar M, Singh G (2018) Acute Pancreatitis and Pulmonary Complications. Chron Obstruct Pulmon Dis Vol No. 3 Iss No. 1:29. Copyright:


Journal of Nanoparticle Research | 2017

Novel aptamer-linked nanoconjugate approach for detection of waterborne bacterial pathogens: an update

Gulshan Singh; Murli Manohar; Anthony Ayodeji Adegoke; Thor Axel Stenström; Rishi Shanker


Energy Conversion and Management | 2017

ACCase and rbcL gene expression as a function of nutrient and metal stress for enhancing lipid productivity in Chlorella sorokiniana

Poonam Singh; Sheena Kumari; Abhishek Guldhe; Gulshan Singh; Faizal Bux

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Thor Axel Stenström

Durban University of Technology

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Murli Manohar

Central Drug Research Institute

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Faizal Bux

Durban University of Technology

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Sheena Kumari

Durban University of Technology

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Abhishek Guldhe

Durban University of Technology

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Folasade Adeyemo

Durban University of Technology

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Isaac Dennis Amoah

Durban University of Technology

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Poonam Singh

Durban University of Technology

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Poovendhree Reddy

Durban University of Technology

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