scholarly journals Joint Action of Two Pesticides and an Oxidase Inhibitor on The Snail Lymnaea Acuminata

Author(s):  
Dr. Archana Dixit and Dr. Surya Prakash Mishra

Studies were conducted on synergism between an Organophosphate, Nuvan (dichlorvos) mixed with a carbamate, Sevin (carbaryl) in a 1:46 ratio against the snail Lymnaea acuminata. It was found that Sevin enhances the activity of Nuvan and thus the LC values ( LC10, LC50, LC90 ) obtained from this mixture were low as compared to Nuvan or Sevin alone. The acetylcholinesterase (AChE) inhibition was higher in case of Nuvan + Sevin (16.17%) as compared to Nuvan or Sevin (34.7% , 69.1%) alone. When Piperonyl Butoxide (PB), a mixed function oxidase inhibitor was given with Nuvan and Sevin in a 1:46:5 ratio, the LC value decrease still further. It appears that, in the tertiary mixture, while PB reduce the oxidative detoxification of Nuvan and Sevin the carbamate may also be preventing the hydrolysis of Nuvan may tertiary mixture lethal than of its components.

1996 ◽  
Vol 10 (1) ◽  
pp. 127-133 ◽  
Author(s):  
Chae Soon Kwon ◽  
Donald Penner

Greenhouse studies showed that the mixed function oxidase inhibitor, piperonyl butoxide (PBO), tank-mixed with the sulfonylurea herbicides, nicosulfuron, primisulfuron, and thifensulfuron, in the absence of effective adjuvants enhanced herbicide activity on both broadleaf and grass weed species. Effective adjuvants for nicosulfuron were K-3000 for common lambsquarters, Sylgard® 309 Surfactant for velvetleaf, K-2000 for barnyardgrass, and K-2000, K-3000, and Scoil® methylated seed oil for giant foxtail control. K-3000 and Sylgard 309 enhanced velvetleaf control with primisulfuron and thifensulfuron. The 28% urea and ammonium nitrate (UAN) was more effective as an adjuvant with thifensulfuron for velvetleaf than for common lambsquarters control. The enhancement of sulfonylurea herbicide activity with PBO was most apparent when other adjuvants were least effective.


Weed Science ◽  
1995 ◽  
Vol 43 (4) ◽  
pp. 561-565 ◽  
Author(s):  
Chae Soon Kwon ◽  
Donald Penner

Greenhouse and laboratory studies were conducted to determine kochia resistance to a spectrum of acetolactate synthase (E.C.4.13.18) (ALS)-inhibiting herbicides. The chlorsulfuron-resistant biotype plants were resistant to six herbicides: triflusulfuron, thifensulfuron, halosulfuron, imazamethabenz, chlorsulfuron, and nicosulfuron. But, the resistant biotypes showed sensitivity similar to the susceptible biotypes to three herbicides: metsulfuron, imazethapyr, and imazaquin. The resistant biotypes were slightly less sensitive to primisulfuron, chlorimuron, and flumetsulam than the sensitive biotypes. The I50values for 50% inhibition of the ALS enzyme indicated that the resistant biotype was 22, 18, and 16 times more resistant to primisulfuron, chlorsulfuron, and thifensulfuron than the susceptible biotype. In contrast, the I50ratios (resistant/susceptible) were 3, 2, and 1 for flumetsulam, nicosulfuron, and imazethapyr, respectively. The altered ALS enzyme system of the resistant biotype showed a differential response for the ALS-inhibiting herbicides. Addition of a mixed function oxidase inhibitor, piperonyl butoxide (PBO) at 2 kg ha−1, to primisulfuron and thifensulfuron increased visual injury and reduced plant height of the chlorsulfuron-sensitive kochia biotype plants. The addition of PBO to primisulfuron enhanced visual injury of the resistant biotype at low rates of primisulfuron.


Weed Science ◽  
1999 ◽  
Vol 47 (5) ◽  
pp. 492-497 ◽  
Author(s):  
Christy L. Sprague ◽  
Donald Penner ◽  
James J. Kells

The antidotes dichlormid, MON-4660, CGA-154281, R-29148, and MON-13900 were tested in the greenhouse to protectZea maysL. (corn) against RPA 201772 injury. High rates of RPA 201772 injured four Z.mayshybrids > 30%. R-29148 and MON-13900 were the most effective of the five antidotes evaluated. R-29148 applied at rates ⩾ 45 g ha−1provided excellent protection against RPA 201772 injury and also prevented injury toZ. maysfrom diketonitrile, the active metabolite of RPA 201772. In laboratory studies, R-29148 did not alter absorption of14C-RPA 201772 from soil; however, R-29148 significantly enhanced the rate of RPA 201772 metabolism and inactivation inZ. mays.The mixed function oxidase inhibitor piperonyl butoxide (PBO) increased RPA 201772 injury on all hybrids. These results demonstrate thatZ. maystolerance to RPA 201772 can be enhanced with the use of antidotes such as R-29148 and MON-13900, that R-29148 protectsZ. maysfrom RPA 201772 and diketonitrile by the enhancement of metabolism, and that oxidative reactions may be involved in the metabolism of RPA 201772 inZ. mays.


Author(s):  
Anja Köhler ◽  
Benjamin Escher ◽  
Laura Job ◽  
Marianne Koller ◽  
Horst Thiermann ◽  
...  

AbstractHighly toxic organophosphorus nerve agents, especially the extremely stable and persistent V-type agents such as VX, still pose a threat to the human population and require effective medical countermeasures. Engineered mutants of the Brevundimonas diminuta phosphotriesterase (BdPTE) exhibit enhanced catalytic activities and have demonstrated detoxification in animal models, however, substrate specificity and fast plasma clearance limit their medical applicability. To allow better assessment of their substrate profiles, we have thoroughly investigated the catalytic efficacies of five BdPTE mutants with 17 different nerve agents using an AChE inhibition assay. In addition, we studied one BdPTE version that was fused with structurally disordered PAS polypeptides to enable delayed plasma clearance and one bispecific BdPTE with broadened substrate spectrum composed of two functionally distinct subunits connected by a PAS linker. Measured kcat/KM values were as high as 6.5 and 1.5 × 108 M−1 min−1 with G- and V-agents, respectively. Furthermore, the stereoselective degradation of VX enantiomers by the PASylated BdPTE-4 and the bispecific BdPTE-7 were investigated by chiral LC–MS/MS, resulting in a several fold faster hydrolysis of the more toxic P(−) VX stereoisomer compared to P(+) VX. In conclusion, the newly developed enzymes BdPTE-4 and BdPTE-7 have shown high catalytic efficacy towards structurally different nerve agents and stereoselectivity towards the toxic P(−) VX enantiomer in vitro and offer promise for use as bioscavengers in vivo.


1989 ◽  
Vol 121 (3) ◽  
pp. 219-223 ◽  
Author(s):  
Everett C. Burts ◽  
Hugo E. van de Baan ◽  
Brian A. Croft

AbstractAdult pear psylla, Psylla pyricola Foerster, from commercial pear orchards near Wenatchee, WA, were tested using a slide-dip technique for susceptibility to fenvalerate over a 5-year period from 1984 to 1988. Results were compared with those from similar tests using psyllids from an unexposed population near Corvallis, OR. During 5 years, resistance of adults to fenvalerate increased by 16- to 32-fold at Wenatchee while that of the Corvallis population did not change. In 1988, tests with five pyrethroids and pyrethroid – piperonyl butoxide combinations indicated that pear psylla adults also were resistant to permethrin and flucythrinate but not to fenpropathrin or cyfluthrin which contain a cyano group that reduces their susceptibility to oxidase metabolism. Piperonyl butoxide synergism was proportional to the level of resistance, indicating that resistance is probably due to increased mixed function oxidase activity. Implications of this study to control of post-diapause winter form adults in commercial pear orchards is discussed.


1991 ◽  
Vol 46 (9-10) ◽  
pp. 893-896 ◽  
Author(s):  
Dale L. Shaner

Abstract The tolerance of maize to root-applied imazethapyr can be increased by pretreating plants with the potassium salt of naphthalic acid (NAK). This safening effect appears to be the result of NAK stimulating the ability of maize to rapidly metabolize imazethapyr to 5′-hydroxyethyl-imazethapyr, possibly through a mixed function oxidase. The safening effect of NAK can be antagonized by 1-aminobenzotriazole (ABT), a mixed function oxidase inhibitor. The increased rate of hydroxylation of imazethapyr to 5′-hydroxyethyl-imazethapyr immobilizes the herbicide in the root system which decreases the accumulation of herbicide in the meristematic tissue. This decreased accumulation, in turn, lowers the phytotoxicity of imazethapyr on maize.


2007 ◽  
Vol 79 (4) ◽  
pp. 469-479 ◽  
Author(s):  
Donglu Bai

Recent studies have proved that huperzine A (HupA) possesses different pharmacological actions other than the inhibition of hydrolysis of ACh. These noncholinergic roles, for instance, the antagonist effect on NMDA receptor, the protection of neuronal cells against β-amyloid, free radicals, and hypoxia-ischemia-induced injury, could be important too in Alzheimer's disease (AD) treatment. The therapeutic effects of HupA are probably based on a multitarget mechanism. By targeting dual active sites of AChE, a series of bis- and bifunctional HupB compounds with various lengths of tether were designed, synthesized, and tested for the inhibition and selectivity of AChE. The most potent bis-HupB compound exhibited increase by three orders of magnitude in AChE inhibition and two orders of magnitude in selectivity for AChE than its parent HupB.


1998 ◽  
Vol 26 (2) ◽  
pp. 301-303
Author(s):  
O. Takahashi ◽  
S. Oishi ◽  
M. Yoneyama ◽  
T. Tanaka ◽  
T. Fujitani

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