Helicoverpa armigera is an insect, causes important economical losses in crops. To reduce this loss, chemical insecticides such as pyrethroids have been commonly used against H. armigera in farming areas all over the world. However, excess and continuous usages of them cause resistance development in H. armigera. Insects develop resistance against applied insecticides by following three main mechanisms / by reducing the amount of insecticide entering into the insect body, developing insensitivity of the insecticide effective site and increasing detoxification metabolism of insecticides such as increased metabolism of them in midgut tissue of H. armigera. Therefore, changes in differentially expressed midgut proteins were analysed at protein level with two-dimensional gel electrophoresis (2D-PAGE) and matrix-assisted laser desorption/ionization-time-of-flight-mass spectrometry (MALDI-TOF-MS) together with examine biochemical activity changes of certain detoxification enzymes such as esterases (EST) and glutathione S-transferases (GST). Moreover, transcriptional level analysis of certain genes from EST and GST systems together with cytochrome P450 monooxygenases (CYP450) system were done with quantitative real-time PCR method, too. According to the comparative proteome analysis, it was found that H. armigera field samples overcome pyrethroid stress mainly by increasing energy metabolism related proteins expressions such as ATP synthase, Vacuolar ATPase A and B and arginine kinase proteins. Furthermore, certain detoxification enzymes such as thioredoxin peroxidase and NADPH cytochrome P450 reductase were up-regulated in Mardin population, suggesting that they were actively participating in response to pyrethroid stress. NADPH cytochrome P450 reductase could play a role in detoxification of toxic pyrethroid metabolites such as 3-phenoxybenzaldehyde. However, while glutathione S-transferases (GSTs) were not found up-regulated in the comparative proteome analysis, biochemical assays (GST-CDNB, GST-DCNB and GST-PNBC) showed significant increases in enzyme activities in the Adana and in the Mardin field population, as compared to the susceptible strain. Furthermore, GST-DCNB and GST-PNBC activities showed significant increase in &Ccedil / anakkale population. As overcoming energy crisis may lead to an increase in oxidative stress, detoxification enzymes (GSTs and thioredoxin peroxidase) might be involved in pathways for eliminating toxic reactive oxygen species such as H2O2. Similarly, although esterases (EST) were not found as differentially expressed, biochemical assays for ESTs showed significant increases in enzymatic activities in the Adana and the Mardin field populations. Thus, ESTs are also proposed to be involved in developing resistance as an initiator of pyrethroid metabolism in H. armigera from Turkey. Quantitative real-time PCR results showed that while CYP9A14 gene expression was up-regulated in all analyzed field populations, CYP9A12 gene expression was up-regulated in both &Ccedil / anakkale and Mardin populations. CYP4S1 gene expression was also up-regulated only in Mardin field population. However, while CYP6B7 gene expression together with CYP9A12 and CYP4S1 genes expressions were down-regulated in Adana population, CYP6B7 gene expression was not significantly changed in both &Ccedil / anakkale and Mardin populations. In addition, GST, GSTX01 and ESTX018 gene expressions were not significantly changed in all field populations in comparison to susceptible population. Therefore, CYP9A14, CYP9A12 and CYP4S1 genes proposed to be involved in detoxification of toxic pyrethroid metabolites possibly through regulation of NADPH cytochrome P450 reductase. In conclusion, it is suggested that one of the main mechanisms of resistance development is increased energy metabolism in the midgut tissue of H. armigera which may be a general prerequisite for compensating the costs of energy-consuming detoxification processes.

During 2013 and 2014, studies were conducted to determine the effects of Helicoverpa zea and Spodoptera frugiperda on both damage and yield of Sorghum bicolor. Results from damage ratings suggest that the amount of damage per single larva decreases as population density increases. Also, yield results suggest that one H. zea and one S. frugiperda larva per panicle results in a 3.6 and 4 percent yield loss, respectively. Additionally, a dynamic EIL was determined using crop value along with various yield potentials and control costs. Other research studies were conducted to determine the efficacy of diamide and pyrethroid insecticides on headworms when applied at midge timing for different locations and planting dates. Results suggest that diamides provide longer and better control of headworms than do pyrethroids. However, applying diamides as a preventative application at midge timing may not be economically feasible when grain prices are low.

The objectives of this study were to establish the effectiveness of chlorpyrifos in suppressing H. armigera population in oranges and to determine the effect chlorpyrifos had on the health of farm pesticide operators. Experiments showed that by applying chlorpyrifos on orange trees, H. armigera larvae population was suppressed significantly. High fruit yields were realized from trees that were sprayed with chlorpyrifos. Visual observation of personnel involved in pesticide related duties, revealed that judicious use of pesticides was not practiced by farm workers in all three farms. Data analysis from questionnaires, health records and interviews proved that farm workers suffered from illnesses that were pesticide related. It was mainly those farm workers in the age group of 31 to 35 years who suffered the most from pesticide related illnesses. / Agriculture and Life Sciences / M. Sc. (Agriculture)

The thesis entitled “Syntheses and Characterization of Novel Materials for Efficacious Anticancer Drug Delivery and Selective Sensing of Bioanalytes” encompasses the syntheses and characterization of various novel materials those are primarily used for efficacious pH-targeted chemotherapy, selective sensing and quantification of ATP inside a single living cell and also for specific sensing of female sex pheromone of certain agriculturally important pests. In recent era of cancer research, pH guided anticancer drug delivery is an emerging field by which not only the drug-sensitive, but also the drug-resistant cancer cell lines can be targeted efficiently. Scientists have paid lot of attentions to this area of research to design biocompatible, pH-responsive drug delivery vehicles, where most of the literatures are end up with complex, elaborated synthetic procedures and use of expensive chemicals. There are only a few reports in the literature on small molecule based drug delivery vehicles, which is not well explored. Herein some of the biocompatible, pH-sensitive lipid and short peptide sequences are synthesized in easy and short synthetic procedures and successfully tested for their efficacious anticancer drug delivery properties by various biophysical and biological techniques. A pH and reduction dual bio-responsive short peptide sequences are also generated in simple steps for the same cause. The formation of different nanostructures from the self-assembly of these short peptides is probed from high level of theoretical calculations and ultimately a well known chemotherapeutic drug, doxorubicin, has been delivered efficiently both to the drug-sensitive and drug-resistant cancer cell lines. In a particular case, in vivo study has also been performed to establish the drug delivery efficacy of those serum-stable vehicles that led to proficient reduction of tumour volume as compared to the free drug. On the other hand, a few of the molecules are synthesized and characterized by various analytical means for the selective sensing and quantification of adenosine 5’-triphosphate (ATP) inside a single living cell. Unique surface functionalized templates are also fabricated over MEMS devices for specific sensing of female sex pheromone of Helicoverpa armigera and Bactocera oleae pest in an agricultural field to detect the early pest infestation. Toward this end, an extensive study on the design, syntheses and characterization of different novel materials is presented below.

The objectives of this study were to establish the effectiveness of chlorpyrifos in suppressing H. armigera population in oranges and to determine the effect chlorpyrifos had on the health of farm pesticide operators. Experiments showed that by applying chlorpyrifos on orange trees, H. armigera larvae population was suppressed significantly. High fruit yields were realized from trees that were sprayed with chlorpyrifos. Visual observation of personnel involved in pesticide related duties, revealed that judicious use of pesticides was not practiced by farm workers in all three farms. Data analysis from questionnaires, health records and interviews proved that farm workers suffered from illnesses that were pesticide related. It was mainly those farm workers in the age group of 31 to 35 years who suffered the most from pesticide related illnesses. / Agriculture and Life Sciences / M. Sc. (Agriculture)