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The toxicological and biochemical properties of four organophosphate (OP) insecticides, chlorpyrifos, diazinon, phosalone and dichlorvos, were examined in terms of the diamond back moth, Plutella xylostella (L.) susceptible (Gu-S) and resistant (Kar-R) to OPs. The Kar-R population had significantly high resistance to chlorpyriphos (69.3 fold), medium resistance to diazinon (14.49-fold) and phosalone (10.3-fold), and had less resistance to dichlorvos (5.17-fold) compared to Gu-S population. DEM and TPP reduced Chlopyrifos resistance of Kar-R population as an inhibitor of glutathione S-transferase (GST) and esterases (EST), respectively. Biochemical studies clarified that GST and EST kinetic parameters in the Kar-R population were significantly higher than parameters of Gu-S population. Moreover, this study examined the Kinetics of hydrolysis of acetylthiocholine iodide, butyrylthiocholine iodide as artificial substrates by AChE of resistant and susceptible population. IC₅₀ of monocrotophos, neostigmine bromide and eserine were also determined on AChE of resistant and susceptible populations. Kinetic analysis and inhibition tests indicated that an alteration in AChE of Kar-R population has an effect on both kinetic and inhibition results. The results distinctly showed that multiple mechanisms such as GST, esterases and altered AChE created chlorpyrifos resistance in the Kar-R and insensitivity of AChE is a significant factor for resistance to conventional OP compounds.
 

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This study was aimed to evaluate the effect of Levels of Choline on the growth performance (WG, SGR, FCR, CF, PER and HIS), Carcass Compositions, and Haematological of Caspian salmon. 270 (8.82±0.38 g) were randomly distributed in 18 fiber glass tank with treeplicatefor 10 weeks. Experimental diets were also prepared by adding 0, 250, 500, 750, 1000 and 2000 mg/kg the basal diet (Control, Cho250، Cho500, Cho1000 and Cho2000) to evaluategrowth performance, carcass composition, and some haematological parameters. The final weight, weight gain, specific growth rate index, proteinefficiency ratio, obesity coefficient, and feed conversion ratio of fish fed with diet containing appropriate levels of choline (750-1000 mg/kg^-1) were significantlyhigher than fish fed with other diets. With increasing choline in fish diet, body fatand protein concentrations significantly increased, but carcass moisture decreased. Also, addition of 750-1000 mg/kg^-1choline to diet caused a significant diference in the activity of liver enzymes (ALT, AST, ALP and LDH), compared with control treatment and 2000 mg/kg^-1.The results showed a significant increase in growth parameters and optimal carcasscomposition of Caspian salmon, the most suitable amount of choline is 750-1000 mg/kg^-1in the fish diet (p<0.05).
The results of this study indicated, that dietaryup to 1000 mg/kg^-1 to be negetivecooparation on growth performance, liver enzymesin Caspian salmon, salmo trutta caspius has moderate Choline requirement 750-1000 mg/kg^-1 as fed

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 Betulin is a pentacyclic lupane-type triterpene, mainly obtained from Betula species plants with a variety of biological actions such as anti-HIV and anticancer properties. This study aimed to enhance the production of betulin in cultures of Betula litwinowii calli under the influence of concentrations and duration time of elicitors and precursors. Collected leaves from Sangdeh habitat in summer, were cultured in WPM medium containing 2,4-D and BAP hormones. Four month calli were sub-cultured in medium containing elicitors such as salicylic acid, chlorocholine chloride and cobalt chloride and precursors such as sucrose, vitamin and glucose. . Calli were harvested from new culture media after two, three and four weeks and their wet and dry weights were calculated. Data analysis was performed based on two-factor factorial experiment (the first factor, elicitors and precursors each in four levels and the second factor, time with three levels) in a completely randomized design with three replications with SPSS software. Duncan's multiple range test were performed to compare the mean (p≤0.01). The results showed that two week elicitation with chlorocholine chloride (1.5 mg/l for one week) was the best with a more than 3-fold increasing in betulin induction compared to the control treatment (0.068 mg / g). The use of vitamin precursor (ten-fold the normal amount in WPM culture medium) for three weeks, causes the highest increase in betulin induction compared to the control (0.1 mg / g, respectively). In general, in the present study, this treatment is introduced as the best. 

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 The toxicity of chlorpyrifos to three Iranian populations of two-spotted spider mite, collected from Isfahan (ISR), Yazd (Yz) and Guilan (GUS2) Provinces were surveyed using the residual contact vial bioassay. The bioassay results showed that resistance ratios of ISR and Yz populations were 176.90 and 9.78 fold compared to the GUS2 population, respectively. Determination of esterase and glutathione-S-transferase activity and their kinetic parameters showed that ISR population had the highest specific activity and specificity constant among the studied populations. Besides, the content of mixed function oxidases in ISR population was the highest. However, synergistic effects of Piperonyl Butoxide, Diethyl Maleate and Triphenyl Phosphate showed that metabolic enzymes did not play an important role in resistance to chlorpyrifos in ISR and Yz populations and enhanced activity of esterase, glutathione-S-transferase and content of mixed function oxidases in these populations were probably due to resistance to some other acaricides. To determine the role of acetylcholinesterase insensitivity in resistance mechanisms, kinetic parameters and inhibitory effect of chlorpyrifos-oxon on this enzyme were investigated. The K_m value of acetylcholinesterase was determined as 0.036, 0.04, and 0.050 mM using acetylthiocholine iodide for GUS2, Yz, and ISR populations, respectively. In addition, the insensitivity ratios of chlorpyrifos-oxon on acetylcholinesterase activity were estimated at 23.30 and 2.96 for ISR and Yz populations, respectively. These results confirmed amino acid substitutions in active site of this enzyme and also indicated that resistant population possed qualitatively altered AChE.

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B-biotype Bemisia tabaci is a severe insect pest worldwide in many ornamental, agricultural, and horticultural crops. Control of this insect is obstructed by resistance to many AcetylCholinEsterase (AChE)-inhibiting insecticides, such as organophosphates and carbamates. In the present work, we evaluated the acetylcholinesterase inhibitory activity of six monoterpenoids namely α-pinene, terpineol, linalool, ß-myrcene, nerol and geraniol in vitro and in vivo. Inhibition of AChE of B. tabaci was measured by colorimetric method. The results showed that all of the monoterpenoids produced AChE inhibitory activity, with IC₅₀ values ranging from 0.96 to 26.85 mM. Alpha-pinene showed the most potent inhibitory activity (IC₅₀= 0.96 mM). Kinetic analysis showed reversible non-competitive type inhibition, revealing that these components might bind both the enzyme alone and the enzyme-substrate. Results demonstrate the AChE inhibitory activity as mode of action of these monoterpenoids at relatively high concentrations. Thus, this could be useful for investigation of new ecofriendly natural insecticidal compounds.

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Diamondback moth (Plutella xylostella) is a serious pest of cruciferous vegetables worldwide. In Iran, it is commonly controlled by using chlorpyrifos. Due to a range of biochemical and behavioral features, this pest can rapidly develop resistance to many insecticides from different groups. To achieve a better resistance management plan, a chlorpyrifos resistant strain of P. xylostella was selected under laboratory conditions and its cross resistance to five other insecticides and resistance characteristics were investigated. After 15 generations of selection, the selected strain (CLRS) developed 39.61-fold higher resistance to chlorpyrifos in comparison with susceptible strain (AL). CLRS exhibited 19.62-, 17.84-, 3.43- and 3.33-fold cross resistance to hexaflumuron, indoxacarb, thiodicarb and flubendiamide, respectively, but showed no cross resistance to abamectin. Synergism and biochemical studies suggested potential involvement of Esterase (EST) in CLRS. However, no difference was seen for Glutahion-S-Transferase (GSTs) and Mixed Function Oxidase (MFO) in CLRS and AL strains. To determine the role of AcetylCholinEsterase (AChE) insensitivity in resistance mechanism, Kinetic parameters (K_m and V_max) and inhibitory effect of chlorpyrifos-oxon on this enzyme were evaluated. Affinities and hydrolyzing efficiencies of AChE in CLRS were higher than AL. This enzyme in CLRS was also less sensitive to inhibition by chlorpyrifos-oxon. Results indicated that chlorpyrifos resistance exhibited cross resistance to other insecticides from different classes and enhanced EST activity and AChE insensitivity were probably the main factors in chlorpyrifos resistance. These results can help the users of insecticides and can delay the resistance development of P. xylostella.