Harpal Singh - Academia.edu (original) (raw)
Papers by Harpal Singh
Electrochemistry Communications, 2008
21-mer peptide acid nucleic acid (PNA) probe specific to 16s–23s rRNA spacer region of Mycobacter... more 21-mer peptide acid nucleic acid (PNA) probe specific to 16s–23s rRNA spacer region of Mycobacterium tuberculosis has been covalently immobilized on polypyrrole–polyvinylsulphonate film electro-chemically deposited onto indium-tin-oxide (ITO) glass for detection of complementary target by monitoring guanine oxidation and redox indicators (methylene blue and ruthenium complex) up to 0.1 fmole, 0.1 attomole and 1.0 pmole, respectively within 30s of hybridization
Explants transformation through Agrobacterium, followed by in vitro regeneration is only method u... more Explants transformation through Agrobacterium, followed by in vitro regeneration is only method used for genetic improvement of cotton. The currently used method are based on somatic embryogenesis, therefore time consuming, genotype-dependent and expensive. We report here a genotype-independent method for genetic transformation of cotton. Embryonic axes of 48 hours of germinating cotton seeds were incised at the cotyledonary node and co-cultivated with A. tumefaciens. Transfected embryos were transferred into test tubes and grown for 10 days at 28 + 2 o C. Later, the seedlings were transferred to pots in glass house. T 1 seeds obtained from the putative T 0 transgenics were screened for the promising transformation events on the basis of formation of root laterals in Hoagland liquid medium containing hygromycin B. The transgenic nature of the positive T 1 seedlings was confirmed by PCR and PCR-Southern analysis. Histochemical assay showed the presence of the GUS reporter protein in ...
Nucleic acid sequence encoding Allium fistulosum leaf agglutinin (AFAL) is disclosed. The inventi... more Nucleic acid sequence encoding Allium fistulosum leaf agglutinin (AFAL) is disclosed. The invention provides Allium fistulosum leaf agglutinin (AFAL) recombinant protein, its encoding nucleotides, primers and the process of preparation thereof, said recombinant protein is useful for insect control and haemagglutination activity. AFAL is found more toxic to sap sucking insect pest Aphis gossypii (cotton aphid) and Bemisia tabaci (whiteflies) as compared to known Allium sativum leaf agglutinin. AFAL can be used in the development of transgenic plants for resistance against sap sucking and chewing pests.
PloS one, 2014
A Japanese man suffered from acute respiratory tract infection after returning to Japan from Bali... more A Japanese man suffered from acute respiratory tract infection after returning to Japan from Bali, Indonesia in 2007. Miyazaki-Bali/2007, a strain of the species of Nelson Bay orthoreovirus, was isolated from the patient's throat swab using Vero cells, in which syncytium formation was observed. This is the sixth report describing a patient with respiratory tract infection caused by an orthoreovirus classified to the species of Nelson Bay orthoreovirus. Given the possibility that all of the patients were infected in Malaysia and Indonesia, prospective surveillance on orthoreovirus infections should be carried out in Southeast Asia. Furthermore, contact surveillance study suggests that the risk of human-to-human infection of the species of Nelson Bay orthoreovirus would seem to be low.
Clinical cancer research : an official journal of the American Association for Cancer Research, Jan 23, 2015
Purpose: The MUC1-C oncoprotein is an intracellular target that is druggable with cell-penetratin... more Purpose: The MUC1-C oncoprotein is an intracellular target that is druggable with cell-penetrating peptide inhibitors. However, development of peptidyl drugs for treating cancer has been a challenge because of unfavorable pharmacokinetic parameters and limited cell penetrating capabilities. Experimental Design: Encapsulation of the MUC1-C inhibitor, GO-203, in novel polymeric nanoparticles (NPs) was studied for effects on intracellular targeting of MUC1-C signaling and function. Results: Our results show that loading GO-203 into tetrablock polylactic acid (PLA)-polyethylene glycol (PEG)-polypropylene glycol (PPG)-PEG copolymers is achievable and, notably, is enhanced by increasing PEG chain length. Additionally, we found that release of GO-203 from these NPs is controllable over at least 7 days. GO-203/NP treatment of MUC1-C-positive breast and lung cancer cells in vitro was more active with less frequent dosing than that achieved with non-encapsulated GO-203. Moreover, treatment wi...
Polymers for Advanced Technologies, 2010
Skip to Main Content. ...
Journal of Applied Polymer Science, 2008
Most known fire-retardant additives, particularly aliphatic phosphates, cause scorching (discolor... more Most known fire-retardant additives, particularly aliphatic phosphates, cause scorching (discoloration) of polyurethane foams because of the sensitivity of the foam components to even low concentrations of acids released on decomposition. Aliphatic phosphates are more ...
The Journal of Physical Chemistry, 1980
Studies of the kinetics of ruthenium(II1) chloride catalyzed oxidation of butan-2-01 and 2-methyl... more Studies of the kinetics of ruthenium(II1) chloride catalyzed oxidation of butan-2-01 and 2-methyl-1-propanol by aqueous alkaline potassium hexacyanoferrate(II1) were made at constant ionic strength. The results show that complex formation between the ruthenium(II1) ...
Journal of Macromolecular Science: Part A - Chemistry, 1990
Antimicrobial sutures were prepared by the radiation grafting of 2-hydroxyethyl methacrylate (HEM... more Antimicrobial sutures were prepared by the radiation grafting of 2-hydroxyethyl methacrylate (HEMA) monomer on polypropylene monofilament. It was found that the inherent characteristics of monofilaments are considerably influenced by the grafting of poly(HEMA). The grafting decreases the crystalline/amorphous ratio in the polymer by the incorporation of amorphous poly(HEMA) grafts. The tensile strength shows slight improvement for a low degree of
Journal of clinical and experimental dentistry, 2012
Techniques and recommendations for the restoration of endodontically treated teeth have changed f... more Techniques and recommendations for the restoration of endodontically treated teeth have changed from the use of custom cast metal post and core system to glass fiber-reinforced (GFRC) post and composite core system. Has this latest prefabricated glass fiber reinforced post and composite core system increased the fracture resistance of teeth and reduced the incidence of unrestorable root fractures. The purpose of this study was to evaluate the incidence of root fracture and mode of failure of endodontically treated teeth restored with two different post and core systems. Forty maxillary central incisors were randomly divided into two groups. (n=20). All teeth received endodontic treatment. First group was restored with custom cast post and core system. Second group was restored with glass fiber post and composite core system. In Both the groups posts were cemented with adhesive resin cement. Compressive load was applied at an angle of 130 to the long axis of teeth at a cross head spe...
Analytica Chimica Acta, 2010
A rapid and semi-quantitative immunochromatographic strip (ICS) test for cortisol analysis in ser... more A rapid and semi-quantitative immunochromatographic strip (ICS) test for cortisol analysis in serum was developed. The test strip was based on a competitive assay format. Colloidal gold nanoparticles were synthesized and coupled with cortisol-3-carboxymethyloxime–adipic acid dihydrazide–bovine serum albumin (F-3-CMO–ADH–BSA) antigen to directly compete with cortisol in human serum samples. F-3-CMO–ADH–BSA–gold label and uncoupled colloidal gold nanoparticles were appropriately characterized using
Clinica Chimica Acta, 2000
BackgroundA rapid and competitive immunochromatographic strip (ICS) test has been developed using... more BackgroundA rapid and competitive immunochromatographic strip (ICS) test has been developed using colloidal gold as nanoprobe for measuring 17-α-hydroxy progesterone in serum which is a marker for congenital adrenal hyperplasia, an inborn error of metabolism.
PLoS ONE, 2013
Background: RNA interference has been emerged as an utmost tool for the control of sap sucking in... more Background: RNA interference has been emerged as an utmost tool for the control of sap sucking insect pests. Systemic response is necessary to control them in field condition. Whitefly is observed to be more prone to siRNA in recent studies, however the siRNA machinery and mechanism is not well established.
Journal of Macromolecular Science, Part C: Polymer Reviews, 2004
Membranes have become a fascinating domain of present day separation science technology and envir... more Membranes have become a fascinating domain of present day separation science technology and environmental care because of their inter disciplinary nature and a wide range of application areas. Membranes play a vital role in a number of domains involving the industrial sector, human health care, and the management of the environment. The application of membrane as solid polymer electrolyte in
Talanta, 2008
The present study demonstrates improvement in sensitivity and specificity of hapten assay by usin... more The present study demonstrates improvement in sensitivity and specificity of hapten assay by using antigen heterology in conjunction with low molecular weight biotin label as compared to high molecular weight horseradish peroxidase (HRP) label. For generation of antiserum, cortisol-3-O-carboxylmethyl-oxime-bovine serum albumin (F-3-CMO-BSA) was used as immunogen whereas, for the preparation of primary label, corticosterone-3-carboxymethyl oxime (B-3-CMO) was coupled with biotinylcaproylhydrazide
British Polymer Journal, 1989
Abstract Poly (vinyl chloride)(PVC) films were grafted with methacrylic acid (MAA) using a simult... more Abstract Poly (vinyl chloride)(PVC) films were grafted with methacrylic acid (MAA) using a simultaneous-irradiation technique. The effect of solvent ratio (methanol-water) on grafting was studied and maximum grafting was found for an equivolume mixture of methanol and ...
British Polymer Journal, 1990
The characterization of poly(viny1 chloride-g-methacrylic acid) (PVC-g-MAA) films, prepared by th... more The characterization of poly(viny1 chloride-g-methacrylic acid) (PVC-g-MAA) films, prepared by the simultaneous-irradiation technique, was undertaken through swelling measurements, attenuated total reflection infrared spectroscopy (ATRIR), scanning electron microscopy (SEM), electron spectroscopy for chemical analysis (ESCA) and thermogravimetric analysis (TGA). The per cent swelling of grafted PVC in various media increased with the increase in the graft level. A higher per cent swelling was observed in 0 . 5~ NaOH aqueous solution relative to that in distilled water. It is concluded from the ATRIR and ESCA studies that the concentration ratio of oxygen to chlorine atoms on the surface of grafted PVC increased compared with unmodified PVC, indicating grafting of methacrylic acid on to the surface. It was also found that the thermal properties of PVC improved after grafting with methacrylic acid.
The Analyst, 2008
Cysteine modified NH 2 -end peptide nucleic acid (PNA) (24-mer) probe and 5¢-thiol end labeled de... more Cysteine modified NH 2 -end peptide nucleic acid (PNA) (24-mer) probe and 5¢-thiol end labeled deoxyribonucleic acid (DNA) probes specific to Mycobacterium tuberculosis have been immobilized onto BK-7 gold coated glass plates for the detection of complementary, one-base mismatch, non-complementary targets and complementary target sequence in genomic DNA of Mycobacterium tuberculosis using a surface plasmon resonance (SPR) technique. The DNA/Au and PNA/Au bio-electrodes have been characterized using contact angle, atomic force microscopy (AFM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetric (CV) techniques, respectively. It is revealed that there is a 252 millidegrees SPR angle change in the case of PNA immobilization and 205 millidegrees for DNA immobilization, indicating increased amount of immobilized PNA molecules. Hybridization studies reveal that there is no binding of the non-complementary target to DNA/Au and PNA/Au electrode. Compared to the DNA/Au bioelectrode, PNA/Au electrode has been found to be more efficient for detection of one-base mismatch sequence. The PNA/Au bioelectrode shows better detection limit (1.0 ng ml -1 ) over the DNA-Au bioelectrode (3.0 ng ml -1 ). The values of the association (k a ) and dissociation rate constant (k d ) for the complementary sequence in case of the PNA/Au bioelectrode have been estimated as 8.5 ¥ 10 4 m -1 s -1 and 3.6 ¥ 10 -3 s -1 , respectively.
PLoS ONE, 2013
Plants naturally emit methanol as volatile organic compound. Methanol is toxic to insect pests; b... more Plants naturally emit methanol as volatile organic compound. Methanol is toxic to insect pests; but the quantity produced by most of the plants is not enough to protect them against invading insect pests. In the present study, we demonstrated that the over-expression of pectin methylesterase, derived from Arabidopsis thaliana and Aspergillus niger, in transgenic tobacco plants enhances methanol production and resistance to polyphagous insect pests. Methanol content in the leaves of transgenic plants was measured using proton nuclear spectroscopy (1H NMR) and spectra showed up to 16 fold higher methanol as compared to control wild type (WT) plants. A maximum of 100 and 85% mortality in chewing insects Helicoverpa armigera and Spodoptera litura larvae was observed, respectively when fed on transgenic plants leaves. The surviving larvae showed less feeding, severe growth retardation and could not develop into pupae. In-planta bioassay on transgenic lines showed up to 99 and 75% reduction in the population multiplication of plant sap sucking pests Myzus persicae (aphid) and Bemisia tabaci (whitefly), respectively. Most of the phenotypic characters of transgenic plants were similar to WT plants. Confocal microscopy showed no deformities in cellular integrity, structure and density of stomata and trichomes of transgenic plants compared to WT. Pollen germination and tube formation was also not affected in transgenic plants. Cell wall enzyme transcript levels were comparable with WT. This study demonstrated for the first time that methanol emission can be utilized for imparting broad range insect resistance in plants.
Plant Signaling & Behavior, 2014
Electrochemistry Communications, 2008
21-mer peptide acid nucleic acid (PNA) probe specific to 16s–23s rRNA spacer region of Mycobacter... more 21-mer peptide acid nucleic acid (PNA) probe specific to 16s–23s rRNA spacer region of Mycobacterium tuberculosis has been covalently immobilized on polypyrrole–polyvinylsulphonate film electro-chemically deposited onto indium-tin-oxide (ITO) glass for detection of complementary target by monitoring guanine oxidation and redox indicators (methylene blue and ruthenium complex) up to 0.1 fmole, 0.1 attomole and 1.0 pmole, respectively within 30s of hybridization
Explants transformation through Agrobacterium, followed by in vitro regeneration is only method u... more Explants transformation through Agrobacterium, followed by in vitro regeneration is only method used for genetic improvement of cotton. The currently used method are based on somatic embryogenesis, therefore time consuming, genotype-dependent and expensive. We report here a genotype-independent method for genetic transformation of cotton. Embryonic axes of 48 hours of germinating cotton seeds were incised at the cotyledonary node and co-cultivated with A. tumefaciens. Transfected embryos were transferred into test tubes and grown for 10 days at 28 + 2 o C. Later, the seedlings were transferred to pots in glass house. T 1 seeds obtained from the putative T 0 transgenics were screened for the promising transformation events on the basis of formation of root laterals in Hoagland liquid medium containing hygromycin B. The transgenic nature of the positive T 1 seedlings was confirmed by PCR and PCR-Southern analysis. Histochemical assay showed the presence of the GUS reporter protein in ...
Nucleic acid sequence encoding Allium fistulosum leaf agglutinin (AFAL) is disclosed. The inventi... more Nucleic acid sequence encoding Allium fistulosum leaf agglutinin (AFAL) is disclosed. The invention provides Allium fistulosum leaf agglutinin (AFAL) recombinant protein, its encoding nucleotides, primers and the process of preparation thereof, said recombinant protein is useful for insect control and haemagglutination activity. AFAL is found more toxic to sap sucking insect pest Aphis gossypii (cotton aphid) and Bemisia tabaci (whiteflies) as compared to known Allium sativum leaf agglutinin. AFAL can be used in the development of transgenic plants for resistance against sap sucking and chewing pests.
PloS one, 2014
A Japanese man suffered from acute respiratory tract infection after returning to Japan from Bali... more A Japanese man suffered from acute respiratory tract infection after returning to Japan from Bali, Indonesia in 2007. Miyazaki-Bali/2007, a strain of the species of Nelson Bay orthoreovirus, was isolated from the patient's throat swab using Vero cells, in which syncytium formation was observed. This is the sixth report describing a patient with respiratory tract infection caused by an orthoreovirus classified to the species of Nelson Bay orthoreovirus. Given the possibility that all of the patients were infected in Malaysia and Indonesia, prospective surveillance on orthoreovirus infections should be carried out in Southeast Asia. Furthermore, contact surveillance study suggests that the risk of human-to-human infection of the species of Nelson Bay orthoreovirus would seem to be low.
Clinical cancer research : an official journal of the American Association for Cancer Research, Jan 23, 2015
Purpose: The MUC1-C oncoprotein is an intracellular target that is druggable with cell-penetratin... more Purpose: The MUC1-C oncoprotein is an intracellular target that is druggable with cell-penetrating peptide inhibitors. However, development of peptidyl drugs for treating cancer has been a challenge because of unfavorable pharmacokinetic parameters and limited cell penetrating capabilities. Experimental Design: Encapsulation of the MUC1-C inhibitor, GO-203, in novel polymeric nanoparticles (NPs) was studied for effects on intracellular targeting of MUC1-C signaling and function. Results: Our results show that loading GO-203 into tetrablock polylactic acid (PLA)-polyethylene glycol (PEG)-polypropylene glycol (PPG)-PEG copolymers is achievable and, notably, is enhanced by increasing PEG chain length. Additionally, we found that release of GO-203 from these NPs is controllable over at least 7 days. GO-203/NP treatment of MUC1-C-positive breast and lung cancer cells in vitro was more active with less frequent dosing than that achieved with non-encapsulated GO-203. Moreover, treatment wi...
Polymers for Advanced Technologies, 2010
Skip to Main Content. ...
Journal of Applied Polymer Science, 2008
Most known fire-retardant additives, particularly aliphatic phosphates, cause scorching (discolor... more Most known fire-retardant additives, particularly aliphatic phosphates, cause scorching (discoloration) of polyurethane foams because of the sensitivity of the foam components to even low concentrations of acids released on decomposition. Aliphatic phosphates are more ...
The Journal of Physical Chemistry, 1980
Studies of the kinetics of ruthenium(II1) chloride catalyzed oxidation of butan-2-01 and 2-methyl... more Studies of the kinetics of ruthenium(II1) chloride catalyzed oxidation of butan-2-01 and 2-methyl-1-propanol by aqueous alkaline potassium hexacyanoferrate(II1) were made at constant ionic strength. The results show that complex formation between the ruthenium(II1) ...
Journal of Macromolecular Science: Part A - Chemistry, 1990
Antimicrobial sutures were prepared by the radiation grafting of 2-hydroxyethyl methacrylate (HEM... more Antimicrobial sutures were prepared by the radiation grafting of 2-hydroxyethyl methacrylate (HEMA) monomer on polypropylene monofilament. It was found that the inherent characteristics of monofilaments are considerably influenced by the grafting of poly(HEMA). The grafting decreases the crystalline/amorphous ratio in the polymer by the incorporation of amorphous poly(HEMA) grafts. The tensile strength shows slight improvement for a low degree of
Journal of clinical and experimental dentistry, 2012
Techniques and recommendations for the restoration of endodontically treated teeth have changed f... more Techniques and recommendations for the restoration of endodontically treated teeth have changed from the use of custom cast metal post and core system to glass fiber-reinforced (GFRC) post and composite core system. Has this latest prefabricated glass fiber reinforced post and composite core system increased the fracture resistance of teeth and reduced the incidence of unrestorable root fractures. The purpose of this study was to evaluate the incidence of root fracture and mode of failure of endodontically treated teeth restored with two different post and core systems. Forty maxillary central incisors were randomly divided into two groups. (n=20). All teeth received endodontic treatment. First group was restored with custom cast post and core system. Second group was restored with glass fiber post and composite core system. In Both the groups posts were cemented with adhesive resin cement. Compressive load was applied at an angle of 130 to the long axis of teeth at a cross head spe...
Analytica Chimica Acta, 2010
A rapid and semi-quantitative immunochromatographic strip (ICS) test for cortisol analysis in ser... more A rapid and semi-quantitative immunochromatographic strip (ICS) test for cortisol analysis in serum was developed. The test strip was based on a competitive assay format. Colloidal gold nanoparticles were synthesized and coupled with cortisol-3-carboxymethyloxime–adipic acid dihydrazide–bovine serum albumin (F-3-CMO–ADH–BSA) antigen to directly compete with cortisol in human serum samples. F-3-CMO–ADH–BSA–gold label and uncoupled colloidal gold nanoparticles were appropriately characterized using
Clinica Chimica Acta, 2000
BackgroundA rapid and competitive immunochromatographic strip (ICS) test has been developed using... more BackgroundA rapid and competitive immunochromatographic strip (ICS) test has been developed using colloidal gold as nanoprobe for measuring 17-α-hydroxy progesterone in serum which is a marker for congenital adrenal hyperplasia, an inborn error of metabolism.
PLoS ONE, 2013
Background: RNA interference has been emerged as an utmost tool for the control of sap sucking in... more Background: RNA interference has been emerged as an utmost tool for the control of sap sucking insect pests. Systemic response is necessary to control them in field condition. Whitefly is observed to be more prone to siRNA in recent studies, however the siRNA machinery and mechanism is not well established.
Journal of Macromolecular Science, Part C: Polymer Reviews, 2004
Membranes have become a fascinating domain of present day separation science technology and envir... more Membranes have become a fascinating domain of present day separation science technology and environmental care because of their inter disciplinary nature and a wide range of application areas. Membranes play a vital role in a number of domains involving the industrial sector, human health care, and the management of the environment. The application of membrane as solid polymer electrolyte in
Talanta, 2008
The present study demonstrates improvement in sensitivity and specificity of hapten assay by usin... more The present study demonstrates improvement in sensitivity and specificity of hapten assay by using antigen heterology in conjunction with low molecular weight biotin label as compared to high molecular weight horseradish peroxidase (HRP) label. For generation of antiserum, cortisol-3-O-carboxylmethyl-oxime-bovine serum albumin (F-3-CMO-BSA) was used as immunogen whereas, for the preparation of primary label, corticosterone-3-carboxymethyl oxime (B-3-CMO) was coupled with biotinylcaproylhydrazide
British Polymer Journal, 1989
Abstract Poly (vinyl chloride)(PVC) films were grafted with methacrylic acid (MAA) using a simult... more Abstract Poly (vinyl chloride)(PVC) films were grafted with methacrylic acid (MAA) using a simultaneous-irradiation technique. The effect of solvent ratio (methanol-water) on grafting was studied and maximum grafting was found for an equivolume mixture of methanol and ...
British Polymer Journal, 1990
The characterization of poly(viny1 chloride-g-methacrylic acid) (PVC-g-MAA) films, prepared by th... more The characterization of poly(viny1 chloride-g-methacrylic acid) (PVC-g-MAA) films, prepared by the simultaneous-irradiation technique, was undertaken through swelling measurements, attenuated total reflection infrared spectroscopy (ATRIR), scanning electron microscopy (SEM), electron spectroscopy for chemical analysis (ESCA) and thermogravimetric analysis (TGA). The per cent swelling of grafted PVC in various media increased with the increase in the graft level. A higher per cent swelling was observed in 0 . 5~ NaOH aqueous solution relative to that in distilled water. It is concluded from the ATRIR and ESCA studies that the concentration ratio of oxygen to chlorine atoms on the surface of grafted PVC increased compared with unmodified PVC, indicating grafting of methacrylic acid on to the surface. It was also found that the thermal properties of PVC improved after grafting with methacrylic acid.
The Analyst, 2008
Cysteine modified NH 2 -end peptide nucleic acid (PNA) (24-mer) probe and 5¢-thiol end labeled de... more Cysteine modified NH 2 -end peptide nucleic acid (PNA) (24-mer) probe and 5¢-thiol end labeled deoxyribonucleic acid (DNA) probes specific to Mycobacterium tuberculosis have been immobilized onto BK-7 gold coated glass plates for the detection of complementary, one-base mismatch, non-complementary targets and complementary target sequence in genomic DNA of Mycobacterium tuberculosis using a surface plasmon resonance (SPR) technique. The DNA/Au and PNA/Au bio-electrodes have been characterized using contact angle, atomic force microscopy (AFM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetric (CV) techniques, respectively. It is revealed that there is a 252 millidegrees SPR angle change in the case of PNA immobilization and 205 millidegrees for DNA immobilization, indicating increased amount of immobilized PNA molecules. Hybridization studies reveal that there is no binding of the non-complementary target to DNA/Au and PNA/Au electrode. Compared to the DNA/Au bioelectrode, PNA/Au electrode has been found to be more efficient for detection of one-base mismatch sequence. The PNA/Au bioelectrode shows better detection limit (1.0 ng ml -1 ) over the DNA-Au bioelectrode (3.0 ng ml -1 ). The values of the association (k a ) and dissociation rate constant (k d ) for the complementary sequence in case of the PNA/Au bioelectrode have been estimated as 8.5 ¥ 10 4 m -1 s -1 and 3.6 ¥ 10 -3 s -1 , respectively.
PLoS ONE, 2013
Plants naturally emit methanol as volatile organic compound. Methanol is toxic to insect pests; b... more Plants naturally emit methanol as volatile organic compound. Methanol is toxic to insect pests; but the quantity produced by most of the plants is not enough to protect them against invading insect pests. In the present study, we demonstrated that the over-expression of pectin methylesterase, derived from Arabidopsis thaliana and Aspergillus niger, in transgenic tobacco plants enhances methanol production and resistance to polyphagous insect pests. Methanol content in the leaves of transgenic plants was measured using proton nuclear spectroscopy (1H NMR) and spectra showed up to 16 fold higher methanol as compared to control wild type (WT) plants. A maximum of 100 and 85% mortality in chewing insects Helicoverpa armigera and Spodoptera litura larvae was observed, respectively when fed on transgenic plants leaves. The surviving larvae showed less feeding, severe growth retardation and could not develop into pupae. In-planta bioassay on transgenic lines showed up to 99 and 75% reduction in the population multiplication of plant sap sucking pests Myzus persicae (aphid) and Bemisia tabaci (whitefly), respectively. Most of the phenotypic characters of transgenic plants were similar to WT plants. Confocal microscopy showed no deformities in cellular integrity, structure and density of stomata and trichomes of transgenic plants compared to WT. Pollen germination and tube formation was also not affected in transgenic plants. Cell wall enzyme transcript levels were comparable with WT. This study demonstrated for the first time that methanol emission can be utilized for imparting broad range insect resistance in plants.
Plant Signaling & Behavior, 2014