Impact of Climate Change on the Distribution of Cinnamomum malabatrum (Laurales—Lauraceae), a Culturally and Ecologically Important Species of Malabar, Western Ghats, India
Article, Diversity, 2025, DOI Link
View abstract ⏷
The impact of climate change on the distribution of Cinnamomum malabatrum (Laurales—Lauraceae), a culturally and ecologically important species in the Malabar region of Western Ghats, India, was studied using a MaxEnt machine learning algorithm. The findings are rooted in extensive field data and advanced modeling techniques. The predicted range shifts and contraction of suitable habitats for the species indicate significant challenges ahead, especially in the Malabar midlands and coastal plains—areas of high endemicity. The proposed conservation strategies provide a comprehensive framework that encompasses the protection of sacred groves, sustainable land-use policies, afforestation, and community conservation strategies within protected areas. This study serves as a clarion call for concerted action and collaboration among researchers, policymakers, local communities, and conservation practitioners to preserve the delicate balance of the ecosystem in the face of environmental change.
Climate change impacts on habitat suitability of Cinnamomum travancoricum (Lauraceae), a critically endangered endemic vascular plant in the Western Ghats, India
Das M.L., Bondada S., Rajesh K., Subrahmanyam S.
Article, Israel Journal of Ecology and Evolution, 2023, DOI Link
View abstract ⏷
The habitat of Cinnamomum travancoricum, a critically endangered endemic vascular plant that thrives at high altitudes (1,500-3,500 m asl) and in moist environments (600-850 hPa) in Western Ghats (WG), is shrinking due to climate change (CC), increase in herbivore populations, urbanization, and over-exploitation of C. travancoricum. Cinnamomum travancoricum's current habitat and predictive range shift were modeled using MaxEnt for 2030, 2050, and 2070 CE under two emission scenarios: Representative Concentration Pathways (RCP) 4.5 and 8.5. The 19 WorldClim bioclimatic variables, including slope, aspect, elevation data, and 16 spatially dispersed-species-occurrence points, were used to predict the potential distribution. Jackknife test identified 'isothermality', 'mean diurnal range', and 'precipitation of the driest month' as the most impactful variables for modeling the habitat and range shift. This MaxEnt model was accurate with an area under curve (AUC) value of 0.995. This ecological model predicted a substantial range contraction in suitable habitats, with 'highly suitable' and 'moderately suitable' habitats shrinking by 100% in RCP 8.5, confirming that C. travancoricum is highly vulnerable to the effects of CC, making it one key species for conservation in WG. The present study suggests the restoration of existing protected areas, creation of specialized reserves, habitat connectivity, and further education towards local communities as the key adaptation strategies for conservation.
Climate Change Projections of Current and Future Distributions of the Endemic Loris lydekkerianus (Lorinae) in Peninsular India
Book chapter, Exploring Synergies and Trade-offs Between Climate Change and the Sustainable Development Goals, 2020, DOI Link
View abstract ⏷
Loris lydekkerianus (L. lydekkerianus) are endemic primates of peninsular India. The current and future potential distribution and range shift of L. lydekkerianus were studied using a maximum entropy (maxent) machine learning algorithm. Four scenarios of the Intergovernmental Panel on Climate Change (IPCC)’s fifth assessment, that is, representative concentration pathway (RCP) 4.5 and RCP 8.5 for the years 2050 and 2070, were examined using observed ecological variables and known data of species occurrence, obtained from both published literature and field surveys. This supplied 200 species occurrence points. Spatial thinning was applied to reduce dataset biases. The preliminary extraction of species occurrence data using quantum geographic information system (QGIS 2.14) generated a residual value of <0.001 reflecting reliable extraction. This ecological model suggests an expansion of potentially suitable habitat of Loris lydekkerianus malabaricus in the central Western Ghats (WG) and shrinking of the habitat of Loris lydekkerianus lydekkerianus in the Eastern Ghats (EG). A third unnamed, undescribed subspecies of Loris lydekkerianus found during this investigation was more vulnerable to climate change. Field-collected datasets confirm that Loris lydekkerianus malabaricus prefer wetter habitats of the WG, whereas Loris lydekkerianus lydekkerianus were more common in the dry, rainshadow areas of the WG and the Deccan plateau, extending into the EG and coastal areas of Tamil Nadu. The unnamed subspecies of L. lydekkerianus (hereafter L. lydekkerianus, ssp. A) prefers an intermediate climatic area, that is, neither the wet parts of the WG nor the dry parts. Ecological models on the future potential distribution of Loris lydekkerianus lydekkerianus predict positive expansion of the habitat for RCP 4.5 for 2050 and 2070, whereas the RCP 8.5 (2050) and RCP 8.5 (2070) scenarios predict high impacts on the habitat due to climate change. Range shift models predict a considerable shift in the present habitat range and expansion for Loris lydekkerianus malabaricus and Loris lydekkerianus lydekkerianus, respectively, and no expansion for the L. lydekkerianus ssp. A for 2050 and 2070. We also predict that suitable habitat areas of L. lydekkerianus ssp. A will shrink by 99%. Therefore, L. lydekkerianus ssp. A stands highly vulnerable to the changing climate of peninsular India.
Ecological modelling of a wetland for phytoremediating Cu, Zn and Mn in a gold–copper mine Site using typha domingensis (Poales: Typhaceae) near Orange, NSW, Australia
Subrahmanyam S., Adams A., Raman A., Hodgkins D., Heffernan M.
Article, European Journal of Ecology, 2017, DOI Link
View abstract ⏷
An artificial wetland was computationally modelled using STELLA®, a graphical programming tool for an Au–Cu mine site in Central-west NSW, the aim of which was to offer a predictive analysis of a proposed wetland for Cu, Zn and Mn removal using Typha domingensis as the agent. The model considers the important factors that impact phytoremediation of Cu, Zn and Mn. Simulations were performed to optimise the area of the wetland; concentration of Cu, Zn and Mn released from mine (AMD); and flow rates of water for maximum absorption of the metals. A scenario analysis indicates that at AMD = 0.75mg/L for Cu, Zn and Mn, 12.5, 8.6, and 357.9 kg of Cu, Zn and Mn, respectively, will be assimilated by the wetland in 35 years, which would be equivalent to 61 mg of Cu/kg, 70 mg of Zn/kg and 2,886 mg of Mn/kg of T. domingensis, respectively. However, should Cu, Zn and Mn in AMD increase to 3 mg/L, then 18.6 kg of Cu and 11.8 kg of Zn, respectively, will be assimilated in 35 years, whereas no substantial increase in absorption for Mn would occur. This indicates that 91 mg of Cu, 96 mg of Zn and 2917 mg of Mn will be assimilated for every kg of T. domingensis in the wetland. The best option for Cu storage would be to construct a wetland of 50,000 m2 area (AMD = 0.367 mg/L of Cu), which would capture 14.1 kg of Cu in 43 years, eventually releasing only 3.9 kg of Cu downstream. Simulations performed for a WA of 30,000 m2 indicate that for AMD = 0.367 mg/L of Zn, the wetland captures 6.2 kg, releasing only 3.5 kg downstream after 43 years; the concentration of Zn in the leachate would be 10.2 kg, making this the most efficient wetland amongst the options considered for phytoremediating Zn. This work will help mine managers and environmental researchers in developing an effective environmental management plan by focusing on phytoremediation, with a view at extracting Cu, Zn and Mn from the contaminated sites.
Effective climate change adaptation strategies for biodiversity conservation
Article, Frontiers in Environmental Science, 2015, DOI Link
View abstract ⏷
Effective Climate Change (CC) adaptation strategies for biodiversity conservation have been heavily discussed recently. Currently, there are ~650 CC adaptation recommendations such as managing healthy vegetation on slopes (Veech, 2003), terrestrial and inland water systems (Settele et al., 2014), landscape restoration efforts (Pradhan and Shrestha, 2007), creation and protection of climate refuges (Lindenmayer et al., 2010), wildlife conservation (Mawdsley et al., 2009) among several others (Grabherr, 2009; Khattak et al., 2010). However, they are vague, lack specific solutions with limited analysis of significant benefits, advantages and disadvantages. Over the last few years, I have been developing a database which critically evaluates a variety of CC adaptation strategies, for several biodiversity conservation scenarios. After performing extensive analysis of the existing recommendations, and comparing them against the database that I have been populating, I have critically identified and analyzed 13 effective adaptation strategies for biodiversity conservation that confer significant ecological benefits, and therefore, I discuss them here as most effective. They are segmented under [1] identification and analysis of existing stressors, [2] initiation of strategic zoning of land uses, [3] better preparation for major disturbances, [4] identification and designation of reserves, and [5] increased communication of knowledge to stakeholders. Intended benefits of such adaptation strategies include [a] improved capacity of decision makers to adapt to CC; [b] ability to adapt CC with specific reference to the interactions between ecosystems, communities and populations; [c] ability to device most appropriate adaptation strategies for different CC scenarios; [d] increased flow of communication; [e] ability to device proactive adaptive strategies for different habitat; [f] establish cross-national collaboration among the organizations; [g]ability to develop guidelines for adapting to CC that is specific for regions prone to extremities of stress, and [h] quantify environmental susceptibility against adaptive capacity, for effective biodiversity conservation (see Table 1).
Optimisation of experimental conditions for synthesis of high affinity MIP nanoparticles
Subrahmanyam S., Guerreiro A., Poma A., Moczko E., Piletska E., Piletsky S.
Article, European Polymer Journal, 2013, DOI Link
View abstract ⏷
Molecularly imprinted nanoparticles were synthesised via iniferter polymerisation in the presence of a chain terminator agent and at high monomer and template concentration. The amount of initiator, chain terminator agent and UV irradiation time were optimised in order to achieve maximum yield of discrete nanoparticles without causing macrogelation of the polymerisation mixture. Resultant particles were then purified from unreacted monomers via gel permeation and characterised by size-exclusion chromatography, dynamic light scattering and electron microscopy. The affinity towards the target was verified via surface plasmon resonance on immobilised templates. The yield of nanoparticles obtained using this approach was 14%, a significant increase when compared with similar methods using high monomer concentration and UV initiation.© 2012 Elsevier Ltd. All rights reserved.
Molecularly imprinted polymer-hybrid electrochemical sensor for the detection of β-estradiol
Des Azevedo S., Lakshmi D., Chianella I., Whitcombe M.J., Karim K., Ivanova-Mitseva P.K., Subrahmanyam S., Piletsky S.A.
Conference paper, Industrial and Engineering Chemistry Research, 2013, DOI Link
View abstract ⏷
This paper discusses the construction of a novel electrochemical sensor for 17β-estradiol (E2) based on a molecularly imprinted polymer (MIP)-conducting polymer modified hybrid electrode. A bifunctional monomer, N-phenylethylene diamine methacrylamide (NPEDMA), was used for the construction of the electrochemical sensor. Conducting films were prepared on the surface of a gold electrode by electropolymerization of the aniline moiety of NPEDMA. A layer of MIP was photochemically grafted over the polyaniline, via N,N-diethyldithiocarbamic acid benzyl ester (iniferter) activation of the methacrylamide groups. Computational modeling was used to select the most suitable monomer for preparation of MIPs for E2. Experimental parameters such as deposition time, cyclic voltammetric (CV) scan cycles, and conditions for polymer accumulation were optimized. The detection limit of the resulting sensor, determined by CV, was 6.86 × 10-7 M. Furthermore, the hybrid electrode was successfully used to analyze E2 in water without complex sample pretreatment. These results reveal that the MIP hybrid sensor has potential to be an effective technique for the electrochemical determination of E2 in real-time in complicated matrices. © 2013 American Chemical Society.
Salivary gland transcriptomes and proteomes of phlebotomus tobbi and phlebotomus sergenti, vectors of leishmaniasis
Rohousova I., Subrahmanyam S., Volfova V., Mu J., Volf P., Valenzuela J.G., Jochim R.C.
Article, PLoS Neglected Tropical Diseases, 2012, DOI Link
View abstract ⏷
Background: Phlebotomus tobbi is a vector of Leishmania infantum, and P. sergenti is a vector of Leishmania tropica. Le. infantum and Le. tropica typically cause visceral or cutaneous leishmaniasis, respectively, but Le. infantum strains transmitted by P. tobbi can cause cutaneous disease. To better understand the components and possible implications of sand fly saliva in leishmaniasis, the transcriptomes of the salivary glands (SGs) of these two sand fly species were sequenced, characterized and compared. Methodology/Principal Findings: cDNA libraries of P. tobbi and P. sergenti female SGs were constructed, sequenced, and analyzed. Clones (1,152) were randomly picked from each library, producing 1,142 high-quality sequences from P. tobbi and 1,090 from P. sergenti. The most abundant, secreted putative proteins were categorized as antigen 5-related proteins, apyrases, hyaluronidases, D7-related and PpSP15-like proteins, ParSP25-like proteins, PpSP32-like proteins, yellow-related proteins, the 33-kDa salivary proteins, and the 41.9-kDa superfamily of proteins. Phylogenetic analyses and multiple sequence alignments of putative proteins were used to elucidate molecular evolution and describe conserved domains, active sites, and catalytic residues. Proteomic analyses of P. tobbi and P. sergenti SGs were used to confirm the identification of 35 full-length sequences (18 in P. tobbi and 17 in P. sergenti). To bridge transcriptomics with biology P. tobbi antigens, glycoproteins, and hyaluronidase activity was characterized. Conclusions: This analysis of P. sergenti is the first description of the subgenus Paraphlebotomus salivary components. The investigation of the subgenus Larroussius sand fly P. tobbi expands the repertoire of salivary proteins in vectors of Le. infantum. Although P. tobbi transmits a cutaneous form of leishmaniasis, its salivary proteins are most similar to other Larroussius subgenus species transmitting visceral leishmaniasis. These transcriptomic and proteomic analyses provide a better understanding of sand fly salivary proteins across species and subgenera that will be vital in vector-pathogen and vector-host research.
Chimeric polymers formed from a monomer capable of free radical, oxidative and electrochemical polymerisation
Lakshmi D., Whitcombe M.J., Davis F., Chianella I., Piletska E.V., Guerreiro A., Subrahmanyam S., Brito P.S., Fowler S.A., Piletsky S.A.
Article, Chemical Communications, 2009, DOI Link
View abstract ⏷
A new monomer, which incorporates both aniline and methacrylamide functional groups, was shown to possess orthogonal polymerisation behaviour to produce conjugated polyaniline suitable for a wide range of applications. © The Royal Society of Chemistry 2009.
Analytical methods for determination of mycotoxins: A review
Review, Analytica Chimica Acta, 2009, DOI Link
View abstract ⏷
Mycotoxins are small (MW ∼700), toxic chemical products formed as secondary metabolites by a few fungal species that readily colonise crops and contaminate them with toxins in the field or after harvest. Ochratoxins and Aflatoxins are mycotoxins of major significance and hence there has been significant research on broad range of analytical and detection techniques that could be useful and practical. Due to the variety of structures of these toxins, it is impossible to use one standard technique for analysis and/or detection. Practical requirements for high-sensitivity analysis and the need for a specialist laboratory setting create challenges for routine analysis. Several existing analytical techniques, which offer flexible and broad-based methods of analysis and in some cases detection, have been discussed in this manuscript. There are a number of methods used, of which many are lab-based, but to our knowledge there seems to be no single technique that stands out above the rest, although analytical liquid chromatography, commonly linked with mass spectroscopy is likely to be popular. This review manuscript discusses (a) sample pre-treatment methods such as liquid-liquid extraction (LLE), supercritical fluid extraction (SFE), solid phase extraction (SPE), (b) separation methods such as (TLC), high performance liquid chromatography (HPLC), gas chromatography (GC), and capillary electrophoresis (CE) and (c) others such as ELISA. Further currents trends, advantages and disadvantages and future prospects of these methods have been discussed. © 2008 Elsevier B.V. All rights reserved.
Electrochemical sensor for catechol and dopamine based on a catalytic molecularly imprinted polymer-conducting polymer hybrid recognition element
Lakshmi D., Bossi A., Whitcombe M.J., Chianella I., Fowler S.A., Subrahmanyam S., Piletska E.V., Piletsky S.A.
Article, Analytical Chemistry, 2009, DOI Link
View abstract ⏷
One of the difficulties with using molecularly imprinted polymers (MIPs) and other electrically insulating materials as the recognition element in electrochemical sensors is the lack of a direct path for the conduction of electrons from the active sites to the electrode. We have sought to address this problem through the preparation and characterization of novel hybrid materials combining a catalytic MIP, capable of oxidizing the template, catechol, with an electrically conducting polymer. In this way a network of "molecular wires" assists in the conduction of electrons from the active sites within the MIP to the electrode surface. This was made possible by the design of a new monomer that combines orthogonal polymerizable functionality; comprising an aniline group and a methacrylamide. Conducting films were prepared on the surface of electrodes (Au on glass) by electropolymerization of the aniline moiety. A layer of MIP was photochemically grafted over the polyaniline, via N,N′-diethyldithiocarbamic acid benzyl ester (iniferter) activation of the methacrylamide groups. Detection of catechol by the hybrid-MIP sensor was found to be specific, and catechol oxidation was detected by cyclic voltammetry at the optimized operating conditions: potential range -0.6 V to +0.8 V (vs Ag/AgCl), scan rate 50 mV/s, PBS pH 7.4. The calibration curve for catechol was found to be linear to 144 μM, with a limit of detection of 228 nM. Catechol and dopamine were detected by the sensor, whereas analogues and potentially interfering compounds, including phenol, resorcinol, hydroquinone, serotonin, and ascorbic acid, had minimal effect (≤3%) on the detection of either analyte. Nonimprinted hybrid electrodes and bare gold electrodes failed to give any response to catechol at concentrations below 0.5 mM. Finally, the catalytic properties of the sensor were characterized by chronoamperometry and were found to be consistent with Michaelis-Menten kinetics. © 2009 American Chemical Society.
An in silico strategy towards the development of legume genome anchor markers using comparative sequence analysis
Schauser L., Subrahmanyam S., Madsen L.H., Sandal N., Stougaard J.
Book chapter, Lotus Japonicus Handbook, 2005, DOI Link
View abstract ⏷
Development of molecular markers and the transfer of marker information from one species to another are limiting steps in the assembly of genetic maps and the use of map information in breeding programs. To identify potential marker sequences more efficiently, we have established procedures combining multi-species EST and genome sequence data for a genome-wide, in silico identification of molecular markers. Taking advantage of information from a few related species, comparative EST sequence analysis identifies evolutionarily conserved sequences (ECSs) that with high probability are conserved in less characterised species in the same family. The chance of observing variation between any two mapping parents is increased by selecting ECS that are interrupted by introns in corresponding genomic regions. Our procedure simultaneously optimizes (1) primer selection for stable performance of PCR across species by choosing ECS as the target sequences for priming, (2) the likelihood of polymorphism discovery by selecting intron-containing ECSs, (3) marker transfer between species, and (4) information content by counting copy numbers of homologous sequences in Arabidopsis. We illustrate our procedure in legumes, where model plant genome and EST sequence data have great potential re influencing crop legume breeding programs.
Application of natural receptors in sensors and assays
Review, Analytical Chemistry, 2002, DOI Link
View abstract ⏷
Biosensors are analytical devices that use a biological or biologically derived material immobilized at a physicochemical transducer to measure one or more analytes. Although there are a large number of reviews on biosensors in general, there has been little systematic information presented on the application of natural receptors in sensor technology. This perspective discusses broadly the fundamental properties of natural receptors, which make them an attractive option for use as biorecognition elements in sensor technology. It analyses the current situation by reference to typical examples, such as the application of nicotinic acetylcholine receptor and G protein-linked receptors in affinity sensors and analyses the problems that need to be resolved prior to any commercialization of such devices.
Amperometric biochemical characterization of isolated fungal strains
Subrahmanyam S., Kodandapani N., Ahamarshan J.N., Ranganathan B., Shanmugam K., Jeyakumar D., Subramanian T.V.
Article, Electroanalysis, 2001, DOI Link
View abstract ⏷
The identification and biochemical characterization of microbial species by electrochemical methods have helped to develop microbial sensors that are rapid and effective. In this article, we present results of biochemical characterization of five fungi, the assimilation and biochemical characterization of various substrates and tolerance to selected inhibitors. The results are based on the respiratory rate and assimilatory profile of these fungi and are more rapid and reliable. The experimental results are discussed here with reference to individual fungus. Further, the advantages of the electrochemical assimilation for the biochemical characterization of the microbes have been discussed.
Voltammetric studies of Aspergillus niger. Assessment of their growth using electroactive extracellular production of metabolite
Subrahmanyam S., Shanmugam K., Murali Madhav V., Murugesan M., Subramanian T.V., Jeyakumar D.
Article, Electroanalysis, 2001, DOI Link
Development of electrochemical microbial biosensor for ethanol based on Aspergillus niger
Subrahmanyam S., Shanmugam K., Subramanian T.V., Murugesan M., Murali Madhav V., Jeyakumar D.
Article, Electroanalysis, 2001, DOI Link
View abstract ⏷
Electrochemical biosensors have become very important tools in analytical chemistry because of their advantages like accuracy, great sensitivity and easy handling. This article reports on the electrochemical detection of ethanol based on the fungus Aspergillus niger. The fungus was isolated from polyurethane waste, at a factory in India. The fungal assimilation of ethanol came to light, when detailed biochemical characterization of the fungus for alcohols, organic acids, and amino acids was studied using cyclic voltammetry. The fungus was cultured in Czepek-Dox media. A dissolved oxygen (DO) probe was fabricated using a gold cathode, a platinum counter electrode and Ag/AgCl reference electrode. The biosensor employed for the assimilation characterization was fabricated by coupling the immobilized membrane with the DO probe using dialysis tubing. A microbial dispersion containing 0.2 g (wet weight) of the organisms/mL was used for immobilization upon cellulose nitrate membrane. The membrane retaining the fungus was placed on the Teflon membrane of the oxygen electrode so that the fungus was trapped between the two membranes. The maximum detectable concentration was 35.3 ppm (v/v) and the linear range was between 1 and 32 ppm (v/v) of ethyl alcohol. By dipping the assembly with the microbe in phosphate buffer, the sensor was found to have an extended lifetime of 90 days with about 1000 determinations.
Cyclic voltammetric measurements of growth of Aspergillus terreus
Subrahmanyam S., Kodandapani N., Shanmugam K., Moovarkumuthalvan K., Jeyakumar D., Subramanian T.V.
Article, Analytical Sciences, 2001, DOI Link
View abstract ⏷
A detailed study using the cyclic voltammogram was done on the live cells of Aspergillus terreus. The peak current values were obtained for different days of growth and plotted against time. The response of cyclic voltammogram showed the phases of the growth of the fungus. The growth curve obtained matched well with the conventional methodology, which assesses the increase of dry weight of the organisms against time. The electrochemical method is more advantageous because it is easy to assess and consumes less time. Further the electrochemical method clearly shows the decline phase which is generally not very defined in the conventional method of assessment of the growth curve. It was confirmed by further experiments that the metabolites were responsible for the anodic peak and not the biomass. Further work is in progress in order to analyze the metabolite(s) that is/are responsible for the anodic peak.
Development of a sensor for acetic acid based on Fusarium solani
Subrahmanyam S., Kodandapani N., Shanmugam K., Moovarkumuthalvan K., Jeyakumar D., Subramanian T.V.
Article, Electroanalysis, 2001, DOI Link
View abstract ⏷
Electrochemical biosensors have become very important tools in analytical chemistry because of their advantages like accuracy, high sensitivity and easy handling. This article describes electrochemical detection of acetic acid based on the fungus Fusarium solani. The biosensor employed for the study of assimilation of substrates was fabricated by coupling the immobilized membrane with the DO probe using dialysis tubing. A microbial dispersion containing 0.2 g of wet weight of the organisms per mL was used for immobilization upon cellulose nitrate membrane. The membrane retaining the fungus was placed on the Teflon membrane of the oxygen electrode so that the fungus was trapped between the two membranes. The linear range was found to be between 2 and 70 ppm (v/v) of acetic acid. A polypropylene net increases the lifetime of the sensor due to its retention of humidity in the net. By dipping the electrochemical probe onto buffer (pH 7.2), the sensor was found to have an extended lifetime of 120 days with about 800 determinations.
A new reactive polymer suitable for covalent immobilisation and monitoring of primary amines
Piletska E.V., Piletsky S.A., Subrahmanyam S., Karim K., Turner A.P.F.
Article, Polymer, 2001, DOI Link
View abstract ⏷
A new polymer capable of reacting with primary amines was synthesised from allyl mercaptan, o-phthalic dialdehyde and ethylene glycol dimethacrylate by radical polymerisation. Reactive hemithioacetal formed by allyl mercaptan and dialdehyde can bind primary amino groups without additional pre-activation forming the fluorescent isoindole complex. It gives a great opportunity to monitor binding and perform loading of the amino compounds onto the reactive surface. The reactive polymer is found to be an effective matrix for immobilisation of the proteins and other amino-containing compounds in affinity chromatography and could be used for their detection in solution. © 2001 Elsevier Science Ltd.
2,4-Toluene diamines – Their carcinogenicity, biodegradation, analytical techniques and an approach towards development of biosensors
Shanmugam K., Subrahmanyam S., Tarakad S.V., Kodandapani N., Stanly D.F.
Review, Analytical Sciences, 2001, DOI Link
View abstract ⏷
2,4-Toluene diamine (TDA), a class A carcinogen, is a major raw material for the productiOn of toluene diisocyanate (TDI), which is one of the precursors for the production of polyurethane foams (PU). This review deals with 2,4-toluene diamine's (TDA) carcinogenicity, analytical techniques, biodegradation and use as a biosensor for biogenic and synthetic amines, emphasizing various carcinogenicity studies by 2,4-TDA on animals and humans. This review reports some publications of the analysis of body fluid samples of workers from a PU producing factory for presence of TDA and TDI, since TDI gets absorbed into the worker's body, getting metabolized into TDA. Biodegradations of 2,4-TDA by various researchers are reported and also our own research experience with biodegradation of 2,4-TDA using Aspergillus nidulans isolated from soil site at a polyurethane foam dumping site have been discussed in this review. Biosensors for various biogenic and synthetic amines are discussed.
‘Bite-and-Switch’ approach using computationally designed molecularly imprinted polymers for sensing of creatinine
Subrahmanyam S., Piletsky S.A., Piletska E.V., Chen B., Karim K., Turner A.P.F.
Conference paper, Biosensors and Bioelectronics, 2001, DOI Link
View abstract ⏷
A method for the selective detection of creatinine is reported, which is based on the reaction between polymerised hemithioacetal, formed by allyl mercaptan, o-phthalic aldehyde, and primary amine leading to the formation of fluorescent isoindole complex. This method has been demonstrated previously for the detection of creatine using creatine-imprinted molecularly imprinted polymers (MIPs) Since MIPs created using traditional methods were unable to differentiate between creatine and creatinine, a new approach to the rational design of a molecularly imprinted polymer (MIP) selective for creatinine was developed using computer simulation. A virtual library of functional monomers was assigned and screened against the target molecule, creatinine, using molecular modelling software. The monomers giving the highest binding score were further tested using simulated annealing in order to mimic the complexation of the functional monomers with template in the monomer mixture. The result of this simulation gave an optimised MIP composition. The computationally designed polymer demonstrated superior selectivity in comparison to the polymer prepared using traditional approach, a detection limit of 25 μM and good stability. The 'Bite-and-Switch' approach combined with molecular imprinting can be used for the design of assays and sensors, selective for amino containing substances. © 2001 Elsevier Science B.V. All rights reserved.
Application of molecularly imprinted polymers in sensors for the environment and biotechnology
Review, Sensor Review, 2001, DOI Link
View abstract ⏷
Molecular imprinting is a generic technology, which introduces recognition properties into synthetic polymers using appropriate templates. Over the last two decades molecularly imprinted polymers (MIPs) have become a focus of interest for scientists engaged in the development of biological and chemical sensors. This is due to the many and considerable advantages they possess in comparison to natural receptors, enzymes and antibodies such as superior stability, low cost and ease of preparation. This brief review covers recent achievements and potential applications of imprinted sensors with specific reference to the environment and biotechnology.
Assessment of growth of Fusarium solani by cyclic voltammetry and possible bioanalytical applications
Subrahmanyam S., Shanmugam K., Madhav V.M., Murugesan M., Subramanian T.V., Jeyakumar D.
Article, Analyst, 2000, DOI Link
View abstract ⏷
Fusarium solani, the fungus isolated from polyurethane waste scraps, was studied for its voltammetric response. The peak current values were obtained for different days and were plotted against time. This electrochemical method based on the voltammetric response showed all the four phases of the growth of the fungus. The growth curve obtained matched well with the conventional methodology, which is obtained by assessing the increase of dry weight of the organisms against time. The electrochemical method is more advantageous than the conventional method because the conventional method is very time consuming and difficult to work with. Further, the electrochemical method clearly shows the decline phase, which is generally not very well defined in the conventional method of assessment of the growth curve. It was confirmed by further experiments that the metabolites were responsible for the anodic peak and not the, fungal biomass. Identification of the metabolites that are responsible for the anodic peak is presently being studied.
