Four species of tephritid fruit flies, Ceratitis capitata, Bactrocera dorsalis, B. cucurbitae, and B. latifrons were evaluated for toxic, developmental, and physiological responses to the chemosterilant lufenuorn incorporated in an agar adult diet and a liquid larval diet. No significant mortality o...
Mathew, G.; Rai, K.S.
The effect of chemosterilant, apholate, on oogenesis has been studied in Aedes aegypti. Treatment of larvae to 20 ppM of the chemical induced ultrastructural changes in the presumptive and primary follicles of the adult ovary. These changes comprised condensation of chromatin, disruption of nuclear envelope and extensive degeneration as evidenced by numerous myelin figures and residual bodies. In some primary follicles, where cellular degeneration was restricted to epithelial cells, no arrest in development was observed. However, in comparison with controls, these follicles also were retarded. Larval treatment with 30 ppM apholate completely suppressed ovariolar development. High incidence of autophagy was observed in tissues at both dose levels.
唐桦; 郑哲民; 杨卫东; 姜文胜; 康忠
Based on the success of the filtration indoor an d outdoor experiment on some chemosterilants, the chemosterilant which developed by the study group and proved having best sterile effect against Anoplophora glabripennis and Tetranychus viennensis, called CSⅡ (wettable powder), we re adopted on the mensuration about the toxicity and sterilizing activity of rats, in order to know the safety about human being. The toxicity including expedit ious toxicity, the influence on sperms and bone marrow derived cells. The result s showed that the expeditious toxicity of CSⅡ is middling; it has no injury on the bone marrow derived cells of rats, but has some actions of deformation on the sperms, so it has sterilizing activity on rats. It is concluded that this chem osterilant can be adopted in trees which are utilized in no edible purpose.
Navarro-Llopis, V; Vacas, S; Sanchis, J; Primo, J; Alfaro, C
During 2008 and 2009, the efficacy of the combination of two Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), control techniques, sterile insect technique (SIT) and a chemosterilant bait station system (Adress), was tested in three crops: citrus (Citrus spp.), stone fruit (Prunus spp.), and persimmon (Diospyros spp.). Two thousand sterile males were released per ha each week in the whole trial area (50,000 ha, SIT area). For 3,600 ha, within the whole trial area, 24 Adress traps per ha were hung (SIT + Adress area). Ten SIT + Adress plots and 10 SIT plots in each of three different fruit crops were arranged to assess Mediterranean fruit fly population densities and fruit damage throughout the trial period. To evaluate the efficacy of each treatment, the male and female populations were each monitored from August 2008 to November 2009, and injured fruit was assessed before harvest. Results showed a significant reduction in the C. capitata population in plots treated with both techniques versus plots treated only with the SIT. Likewise, a corresponding reduction in the percentage of injured fruit was observed. These data indicate the compatibility of these techniques and suggest the possibility of using Adress coupled with SIT to reduce C. capitata populations in locations with high population densities, where SIT alone is not sufficiently effective to suppress fruit fly populations to below damaging levels.
Siefkes, Michael J.; Bergstedt, Roger A.; Twohey, Michael B.; Li, Weiming
Release of males sterilized by injection with bisazir is an important experimental technique in management of sea lamprey (Petromyzon marinus), an invasive, nuisance species in the Laurentian Great Lakes. Sea lampreys are semelparous and sterilization can theoretically eliminate a male's reproductive capacity and, if the ability to obtain mates is not affected, waste the sex products of females spawning with him. It has been demonstrated that spermiating males release a sex pheromone that attracts ovulating females. We demonstrated that sterilized, spermiating males also released the pheromone and attracted ovulating females. In a two-choice maze, ovulating females increased searching behavior and spent more time in the side of the maze containing chemical stimuli from sterilized, spermiating males. This attraction response was also observed in spawning stream experiments. Also, electro-olfactograms showed that female olfactory organs were equally sensitive to chemical stimuli from sterilized and nonsterilized, spermiating males. Finally, fast atom bombardment mass spectrometry showed that extracts from water conditioned with sterilized and nonsterilized, spermiating males contained the same pheromonal molecule at similar levels. We concluded that injection of bisazir did not affect the efficacy of sex pheromone in sterilized males.
Reinbold, James B; Coetzee, Johann F; Hollis, Larry C; Nickell, Jason S; Riegel, Casey; Olson, K C; Ganta, Roman R
Chemosterilization is reported in cattle fed chlortetracycline hydrochloride (CTC) at dosages ranging from 1.1mg/kg for 120 days to 11 mg/kg for 30-60 days. The relationship between plasma CTC drug concentration and carrier clearance has not been described. Chronic carrier status was established in 21 steers with a Virginia isolate of Anaplasma marginale and confirmed by cELISA and an A. marginale-specific RT-PCR. Four negative, splenectomized steers served as active disease transmission sentinels. Steers were randomized to receive 4.4 mg/kg/day (LD); 11 mg/kg/day (MD); or 22 mg/kg/day (HD) of oral chlortetracycline; or placebo (CONTROL) for 80 days. The LD, MD and HD treatment groups consisted of 5 infected steers and 1 splenectomized steer; CONTROL group had six infected steers and 1 splenectomized steer. The daily treatments and ration were divided equally and fed twice daily. Blood samples were collected semi-weekly for determining plasma drug concentration by ultrahigh performance liquid chromatography-mass spectrometry/mass spectrometry method and assessment of disease status by both cELISA and RT-PCR. Mean (CV%) chlortetracycline plasma drug concentrations in the LD, MD, and HD groups were 85.3 (28%), 214.5 (32%) and 518.9 (40%)ng/mL during days 4 through 53 of treatment. A negative RT-PCR assay result was confirmed in all CTC-treated groups within 49 days of treatment; however, cELISA required an additional 49 to 88 days before similar results. Subinoculation of splenectomized steers confirmed chemosterilization. These results are important for influencing future chemosterilization strategies and impacting free trade policy among countries and regions of contrasting endemicity.
The advances in the application of sterilizing techniques against pest rodents in China are introduced in the paper. The development of chemosterilants, improvements of botanic sterilants, production of new steroid hormone sterilants, introduction of immunosterility and excellent properties of the sterilants are outlined. The "Space Occupation Theory" of sterile techniques is advanced after practice. The botanic sterilants with gossypol and trichosanthin as its main agents were screened and successfully applied in the large area control in the northern forest area of China. The safety of sterilants to non-target animals such as rats, rabbits, dogs, monkeys and chickens was summarized.
Le, Binh V.; Nguyen, Jennifer B.; Logarajah, Shankar; Wang, Bo; Marcus, Jacob; Williams, Hazel P.; Catteruccia, Flaminia; Baxter, Richard H. G.
Male Anopheles mosquitoes coagulate their seminal fluids via cross-linking of a substrate, called Plugin, by the seminal transglutaminase AgTG3. Formation of the “mating plug” by cross-linking Plugin is necessary for efficient sperm storage by females. AgTG3 has a similar degree of sequence identity (∼30%) to both human Factor XIII (FXIII) and tissue transglutaminase 2 (hTG2). Here we report the solution structure and in vitro activity for the cross-linking reaction of AgTG3 and Plugin. AgTG3 is a dimer in solution and exhibits Ca2+-dependent nonproteolytic activation analogous to cytoplasmic FXIII. The C-terminal domain of Plugin is predominantly α-helical with extended tertiary structure and oligomerizes in solution. The specific activity of AgTG3 was measured as 4.25 × 10−2 units mg−1. AgTG3 is less active than hTG2 assayed using the general substrate TVQQEL but has 8–10× higher relative activity when Plugin is the substrate. Mass spectrometric analysis of cross-linked Plugin detects specific peptides including a predicted consensus motif for cross-linking by AgTG3. These results support the development of AgTG3 inhibitors as specific and effective chemosterilants for A. gambiae. PMID:23288850
Schermeister, L.J.; Sandal, P.C.; Frye, R.D.
Over 3000 crude water, alcohol and pet-ether plant part extracts were bioassayed with mosquitoes and Drosophila in an effort to identify agents which specifically interfere with insect metamorphosis, and which could provide environmentally safe insect control. About 10% of the extracts modified metamorphosis. Juvenile hormone type activity was noted in some extracts. Preliminary fractionation of promising extracts revealed fractions-bioassay results similar to that of the crude extracts. Exact nature of active fractions was not fully determined; however, flavanoids, alkaloids, and glycosides were suggested. Other agents including teratogens, hormones, and chemosterilant apholate, and gamma-radiation showed promise as potential vector control agents. Wing movements, sound patterns, and population dynamics of mosquitoes were studied as a step toward developing insect behavior and confusion and surveillance techniques. Transmission electron microscopy revealed the morphological nature of the cuticle layer of mosquito but additional studies are needed to understand chemical penetration of the cuticle. The septum of mosquito testes was found to be layered and surrounded by mitochondria. Ovaries were cultured on artificial media and a stain for neurosecretory activity was developed. Synthesis of Difluroperazine dihydro chloride and position labeling was achieved.
Twohey, Michael B.; Heinrich, John W.; Seelye, James G.; Fredricks, Kim T.; Bergstedt, Roger A.; Kaye, Cheryl A.; Scholefield, Ron J.; McDonald, Rodney B.; Christie, Gavin C.
The implementation of a sterile-male-release technique from 1991 through 1999 and evaluation of its effectiveness in the Great Lakes sea lamprey (Petromyzon marinus) management program is reviewed. Male sea lampreys were injected with the chemosterilant bisazir (P,P-bis(1-aziridinyl)-N-methylphosphinothioic amide) using a robotic device. Quality assurance testing indicated the device delivered a consistent and effective dose of bisazir. Viability of embryos in an untreated control group was 64% compared to 1% in a treatment group. A task force developed nine hypotheses to guide implementation and evaluation of the technique. An annual average of 26,000 male sea lampreys was harvested from as many as 17 Great Lakes tributaries for use in the technique. An annual average of 16,100 sterilized males was released into 33 tributaries of Lake Superior to achieve a theoretical 59% reduction in larval production during 1991 to 1996. The average number of sterile males released in the St. Marys River increased from 4,000 during 1991 to 1996 to 20,100 during 1997 to 1999. The theoretical reduc-stertion in reproduction when combined with trapping was 57% during 1991 to 1996 and 86% during 1997 to 1999. Evaluation studies demonstrated that sterilized males were competitive and reduced production of larvae in streams. Field studies and simulation models suggest reductions in reproduction will result in fewer recruits, but there is risk of periodic high recruitment events independent of sterile-male release. Strategies to reduce reproduction will be most reliable when low densities of reproducing females are achieved. Expansion of the technique is limited by access to additional males for sterilization. Sterile-male release and other alternative controls are important in delivering integrated pest management and in reducing reliance on pesticides.