Sublethal effects of chlorantraniliprole to Helicoverpa armigera （Hiibner） larvae were evaluated through exposure of third instar larvae to the insecticide incorporated into an artificial diet. When larvae were fed ...Sublethal effects of chlorantraniliprole to Helicoverpa armigera （Hiibner） larvae were evaluated through exposure of third instar larvae to the insecticide incorporated into an artificial diet. When larvae were fed on the insecticide-containing diet for 7 d, the LC10, LC20, LC40, and LC50values were 3.790, 7.977, 21.577, and 33.121 μg active ingredient L^-1, respectively. Chlorantraniliprole at sublethal concentrations significantly reduced the larval body mass, emergence ratio, adult longevity and egg hatching rate in both the parental and offspring generations. The pupation and copulation rate in the parental generation and the pupal mass in the offspring also strongly decreased. Reproduction was seriously disturbed in both the parental and offspring groups even when only one of the partners was exposed to chlorantraniliprole at larval stages. However, at the lowest concentration of exposure （LC^0）, offspring fecundity was strongly reduced only when both partners were exposed. The net reproductive rate （R0）, intrinsic rate of increase （rm）, and gross reproduction rate （GRR） at LC20, LC40 concentrations were significantly lower than that of the control. Post-exposure effects also included an extended larval developmental time and increased male proportion in both generations. The doubling time （Dt） at LC20, LC40 concentrations as well as gross reproduction rate （GRR） at LC10 concentration were also significantly increased. Chlorantraniliprole might have significant effects on H. armigera population dynamics even at sublethal concentrations on both parental and offspring generations.展开更多
The cotton aphid,Aphis gossypii Glover(Hemiptera:Aphididae),is an important insect pest of cotton crops worldwide.The objectives of this study were to determine the acute toxicity of afidopyropen and whether there are...The cotton aphid,Aphis gossypii Glover(Hemiptera:Aphididae),is an important insect pest of cotton crops worldwide.The objectives of this study were to determine the acute toxicity of afidopyropen and whether there are any effects of sublethal concentrations of afidopyropen on the biological characteristics of A.gossypii.The results showed that afidopyropen possesses high acute toxicity to adult A.gossypii with a 72 h LC_(50) value of 1.062 mg L^(–1).A sublethal concentration(LC_(10))of afidopyropen significantly decreased adult longevity,fecundity and oviposition days of female adults in both F0 and F1 generations.The total pre-adult survival of F_(1) progeny was also significantly reduced by 30%at the LC_(10) of afidopyropen.In addition,the nymph developmental time,pre-adult period,adult pre-reproductive period(APRP),and total pre-reproductive period(TPRP)of the F1 progeny were significantly prolonged compared with the control.Several population parameters,including the net reproductive rate(R_(0)),intrinsic rate of increase(r)and finite rate of increase(λ)of F_(1) progeny were significantly decreased by a sublethal afidopyropen concentration exposure.These results indicated that sublethal concentration of afidopyropen can significantly suppress A.gossypii population growth.It would be useful for assessing the overall effects of afidopyropen on A.gossypii.展开更多
Metaflumizone is a novel sodium channel blocker insecticide, which has been registered for controling the diamondback moth （DBM）, Plutella xylostella （Lepidoptera： Plutellidae） in China. It is unavoidable for DBM...Metaflumizone is a novel sodium channel blocker insecticide, which has been registered for controling the diamondback moth （DBM）, Plutella xylostella （Lepidoptera： Plutellidae） in China. It is unavoidable for DBMs to be exposed to sublethal dose of metaflumizone in brassicaceous vegetable field. Sublethal effects of metaflumizone at LC15 （1.06 mg L-1） and LCz5 （2.03 mg L-1） on the biological characteristics were investigated. Pupation rate, pupal period and pupal weight were significantly declined comparing with the control （P=0.05） when third instar larvae were exposed to LC15 and LC25 of metaflumizone. Comparing the control group to LC15 and LC25 treatment groups, there were significant differences in the development periods of eggs, first instar larvae, pupae and total preoviposition period. The peak of age-specific fecundity in LC15 and LC25 treatment groups was lagged behind control group. Mean values of intrinsic rate of increase （rm）, net reproductive rate （R0） and finite rate of increase （λ） observed from the LCl5 and LC25 treatment groups were lower than those from the control group. But mean values of gross reproduction rate （GRR） was not different. The mean generation time （T） of the treatment groups was prolonged. Whether sublethal doses of metaflumizone could stimulate reproduction in the long term needs further investigation on continuous generations.展开更多
The green miridbug,Cyrtorhinus lividipennis,is an important predator of the rice brown planthopper,Nilaparvata lugens.In this study,the selective toxicity of seven commercial biopesticides for C.lividipennis was exami...The green miridbug,Cyrtorhinus lividipennis,is an important predator of the rice brown planthopper,Nilaparvata lugens.In this study,the selective toxicity of seven commercial biopesticides for C.lividipennis was examined under laboratory conditions; abamectin was the most selective to C.lividipennis,followed by matrine and azadirachtin.Veratridine,rotenone,Bacillus thuringiensis and Beauveria bassiana showed less selectivity for C.lividipennis.Subsequently,matrine,abamectin and azadirachtin were selected for sublethal assessments with respect to C.lividipennis due to their high toxicities to N.lugens.C.lividipennis treated with sublethal concentrations(LC10 and LC20) of the three biopesticides could distinguish volatiles released from healthy and N.lugens-infested plants indicating that the biopesticides tested did not affect the foraging ability of surviving miridbugs.Azadirachtin decreased the consumption capability of C.lividipennis when the densities of N.lugens were 20,30,40 and 50 insects per vial.Sublethal concentration treatment did not impact the pre-oviposition period or egg hatchability of C.lividipennis.However,the fecundity of C.lividipennis exposed to azadirachtin and abamectin increased by 27–41% compared to the untreated individuals.In summary,abamectin or matrine together with C.lividipennis could be considered an effective,sustainable pest management strategy for rice.展开更多
Sitobion avenae(F.) and Rhopalosiphum padi(L.) are two important pests of wheat in China.They typically coexist in fields during the late period of wheat growth.Sulfoxaflor is a novel sulfoximine insecticide that demo...Sitobion avenae(F.) and Rhopalosiphum padi(L.) are two important pests of wheat in China.They typically coexist in fields during the late period of wheat growth.Sulfoxaflor is a novel sulfoximine insecticide that demonstrates broad-spectrum efficacy,especially in targeting sap-feeding insects.This study was carried out to investigate the sublethal effects of sulfoxaflor on the development,longevity,and reproduction of two species of wheat aphids.Our results showed that sublethal concentrations of sulfoxaflor did not cause significant effects on the fecundity or the longevity of the parent generation(F0 generation) of either S.avenae or R.padi.However,it caused transgenerational sublethal effects.For S.avenae,adult longevity of F1 generation was significantly decreased.No significant differences were observed on the population parameters of S.avenae in the F1 generation.For R.padi,the adult preoviposition period(APOP) and the total preoviposition period(TPOP) of F1 generation were significantly reduced.The mean generation time(T) was significantly reduced in the R.padi F1 generation.What’s more,the intrinsic rate of increase(rm) and the finite rate of increase(λ) were significantly increased in the R.padi F1 generation.Taken together,these results suggest that exposure to the LC25 of sulfoxafl had no effects on the parent generation of S.avenae or R.padi,but it reduced adult longevity of S.avenae as a negative effect and increased the rm and λ of R.padi in the first progeny generation,which may have an impact on the population dynamics of R.padi.展开更多
The effects of sublethal doses （LD10：1.00 ng larval-1; LD30： 3.75 ng larva-1） of chlorfluazuron on number and size of developmental spermatocytes in pupal-testis during spermatogenesis of the common cutworm, Spodo...The effects of sublethal doses （LD10：1.00 ng larval-1; LD30： 3.75 ng larva-1） of chlorfluazuron on number and size of developmental spermatocytes in pupal-testis during spermatogenesis of the common cutworm, Spodoptera litura （F.） are described. Chlorfluazuron was applied topically to newly-ecdysed fifth-instar larvae of S. litura under laboratory conditions. During first day of pupation, spermatids were the highest （3,430 ± 7）, however, elongated spermatocytes with mature sperm were the lowest （292 ± 16） in number in pupal-testis compared with other developing spermatocytes. During last day of pupation, elongated spermatocytes with mature sperm were the highest （3,581 ± 3）, however, spermatogonia were the lowest （86± 4） in number in pupal-testis compared with other developing spermatocytes. The number of spermatogonia, primary and secondary spermatocytes, spermatids and elongated cysts with mature sperm were increased during pupal-developmental days in the controls. However, their numbers were significantly reduced in LD10- and even more significantly reduced in LD30-treated pupal-testis compared with controls. Moreover, eupyrene sperm bundles were not present in pupal-testis. During pupal-developmental days, spermatids were the smallest （4.1 ± 0.9 dm in μm） and secondary spermatocytes were the largest （31.0 ± 1.8 dm in μm） in size compared with other developing spermatocytes. The sizes of the same developing spermatocytes were significantly reduced in LD10-treated and more significantly reduced in LD30-treated pupal-testis of S. litura compared with controls.展开更多
Lead has been recognized as a high risk toxic for most organisms including human. The effects of Pb in non-mammalian vertebrates are oprly known, particularly in anuran amphibians. The purpose of this study was to det...Lead has been recognized as a high risk toxic for most organisms including human. The effects of Pb in non-mammalian vertebrates are oprly known, particularly in anuran amphibians. The purpose of this study was to determine the effect of this metal on some hematological parameters of adult Bufo arenarum. It was found that all parameters remained unaltered within normal ranges, with the exception of reticulocyte counts which was significantly increased compared to the in controls (3. 7% vs. 0. 2 % ). It is suggested that the selective change found in reticulocyte count might be considered as an early response of a biomarker to sublethal exposition of Bufo arenarum to lead.展开更多
The time-course and dose-related action of amitraz (AMZ) on gut lipids of worker honeybees were examined over 3 hours following in vivo injections of 0.25, 0.5, 1 and 2 nmols of pesticide per bee. Significant decrease...The time-course and dose-related action of amitraz (AMZ) on gut lipids of worker honeybees were examined over 3 hours following in vivo injections of 0.25, 0.5, 1 and 2 nmols of pesticide per bee. Significant decreases were observed at 30-45 min with 0.25 nmols per bee, for phospholipids, fatty acids, steroids and triacylglycerols. However increases were observed either later or with higher doses. The decreasing action observed with 0.25 nmol AMZ per bee was inhibited by simultaneous injections of the a antagonist phentolamine (from 0.25 to 2.0 nmols per bee). The toxicity of AMZ to honeybees thus likely involves the mobilization of lipids from the gut, via action of this formamidine pesticide on a-adrenoceptors.展开更多
Chlorfluazuron is an insect growth regulator for controlling the major insect pests in crops. This paper describes the effects of sublethal doses （LD10：1.00 ng/larva; LD30：3.75 ng/larva） of chlorfluazuron on ovari...Chlorfluazuron is an insect growth regulator for controlling the major insect pests in crops. This paper describes the effects of sublethal doses （LD10：1.00 ng/larva; LD30：3.75 ng/larva） of chlorfluazuron on ovarioles during ovarian development and oogenesis of common cutworm, Spodoptera litura （F.）. It is a significant pest of cotton, tobacco and miscellaneous vegetables. The LDlo or LD3o was applied topically to the newly-ecdysed fifth-instars of S. litura under laboratory conditions. In controls, on 2nd day of adult emergence, the cell density in germarium was 1636 ± 9.17 nuclei/mm^2. It increased until 3rd day, i.e., 1829 ± 8.87 nuclei/mm^2 and decreased thereafter. In the LDloor LD-3o-treated insects, the patterns of the cell density was the same as in controls but values were significantly （P 〈 0.05） decreased in the LD10- and more in the LDa0-treated females compared with controls. In control, ovaries were normal type and had mature ova with an occasional one or two being absorbed. In LD10-treated females, ovaries had spaces in ovarioles and absorption of ova. In LD30-treated females, besides the spacing and absorption, sometimes only immature （germarium） ova were found.展开更多
Chlorfluazuron is an insect growth regulator for controlling the major insect pests in crops. This paper describes the effects of sublethal doses （LD10：1.00 ng/larva; LD3o： 3.75 ng/larva） of chlorfluazuron on sper...Chlorfluazuron is an insect growth regulator for controlling the major insect pests in crops. This paper describes the effects of sublethal doses （LD10：1.00 ng/larva; LD3o： 3.75 ng/larva） of chlorfluazuron on spermatogenesis in the adults of the common cutworm, Spodoptera litura （F.）. Chlorfluazuron was applied topically to the newly-ecdysed fifth-instars ofS. litura under laboratory conditions. The secondary spermatocytes, spermatids, elongated spermatocytes with mature sperm and eupyrene sperm bundles were present in testis of newly emerged, 1 and 2 day-old adults, but gradually decreased in their numbers in the controls. However, the spermatogonia were not present in newly emerged, 1 and 2 day-old adults. Moreover, primary spermatocytes were present （174 ± 4.0） in newly emerged adults, but not found in 1 and 2 day-old adults. In the testes of newly emerged LD10-treated adults, the numbers of eupyrene and apyrene sperm bundles were significantly reduced compared with controls, and even significantly reduced in LD30-treated adults compared with LDlo, however, their ratios were not affected. Moreover, the pattern of spermatogenesis was the same in LD10- and LD30-treated male adults compared with controls. Furthermore, numbers of developing spermatocytes were significantly reduced in the LD10 compared with controls, and even significantly reduced in LD30-treated male adults compared with LD10. In newly emerged adults, the width and length of elongated spermatocytes with mature sperm were significantly reduced in LDlo- and more significantly reduced in LD30-treated compared with controls of S. litura. In vas deferens of untreated pre- and newly emerged adult male, both eupyrene and apyrene sperm bundles were found, however, in treated pre-adult male, only apyrene sperm bundles and in treated newly emerged adult male, fe, w eupyrene and numerous apyrene sperm bundles were found. It is concluded that spermatogenesis was significantly affected by chlorfluazuron.展开更多
The present study is on the haematological and hepatic responses of the African catfish fingerlings Clarias gariepinus to sublethal toxicity of industrial effluents(IE)from the environment of Ologe Lagoon,Lagos,Nigeri...The present study is on the haematological and hepatic responses of the African catfish fingerlings Clarias gariepinus to sublethal toxicity of industrial effluents(IE)from the environment of Ologe Lagoon,Lagos,Nigeria.The fish were cultured in five concentrations of industrial effluents:0%(control),5%,15%,25%,and 35%.Trials were carried out in triplicates for twelve(12)weeks.The culture system was a static renewable bioassay and was carried out in the fisheries laboratory of the Lagos State University,Ojo-Lagos.Weekly physico-chemical parameters:Temperature(°C),pH,conductivity(ppm)and dissolved oxygen(DO in mg/L)were measured in each treatment tank.Haematological parameters:packed cell volume(PCV),red blood cells(RBC),white blood cell(WBC),neutrophil and lymphocytes etc.,and hepatological alterations were measured after 12 weeks.The physico-chemical parameters showed that the pH ranged from 7.82±0.25~8.07±0.02.DO ranged from 1.92±0.66~4.43±1.24 mg/L.The conductivity values increased with increase in concentration of I.E.While the temperature difference remained insignificant with mean value range between 26.08±2.14~26.38±2.28.The DO showed significant differences at p<0.05.Though survival was 100%during the sublethal study,haematological results showed that C.gariepinus had PCV ranging from 13.0±1.7~27.7±0.6,RBC ranged from 4.7±0.6~9.1±0.1,and neutrophil ranged from 26.7±4.6~61.0±1.0 amongst others.The highest values of these parameters were obtained in the control and lowest at 35%.While the reverse effects were observed for WBC and lymphocytes,the liver shows normal liver cells in the control(0%),but at higher toxic levels,there were:vacoulation,destruction of the hepatic parenchyma,tissue becoming eosinophilic(i.e.tending towards Carcinogenicity)and severe disruption of the hepatic cord architecture.This study therefore shows that disposal of effluents into the aquatic environment affects the health of fishes by impairing normal hepatic functions and hindering vital physiological processes if exposure continues for a long period of time(sublethal effect).展开更多
Histopathological alterations induced by the sublethal concentration of (0.03 ppm) mercuric chloride solution on the epidermis of the fresh-water catfish Heteropneuates fossilis have been studied. It induces slow but ...Histopathological alterations induced by the sublethal concentration of (0.03 ppm) mercuric chloride solution on the epidermis of the fresh-water catfish Heteropneuates fossilis have been studied. It induces slow but significant histopathological changes in the various cellular components of the epidermis. It induces vacuolization, necrosis and pycnosis of the nuclei of the epithelial cells which subsequently shed. Loosening of epithelial cells of the outermost and middle layers following degeneration of the intercellular material and widened intercellular spaces is another important alteration. Prolonged mercury treatment also causes a gradual decrease in staining intensity for sulphated glycosaminoglycans in the outer border of the most superficial layer epithelial cells. The glandular elements (club cells and mucocytes) also get affected, showing cyclic degeneration followed by regeneration.展开更多
Considering the influence of sublethal concentration of pesticides on pests and natural enemies,we propose a pest-management model with impulsive effect on chemical control and biological control strategies periodic s...Considering the influence of sublethal concentration of pesticides on pests and natural enemies,we propose a pest-management model with impulsive effect on chemical control and biological control strategies periodic spraying pesticide and releasing predatory natural enemies.By using the Floquet theory and the comparison theorem of impulsive differential equations,a sufficient condition for the global asymptotic stability of the pest-eradication periodic solution is obtained.The persistence of the system is further studied,and a sufficient condition for the persistence of the system is obtained.Finally,some numerical simulations are shown to verify our theoretical works.Our works indicate that the sublethal effects of insecticides and the release of predatory natural enemies play significant roles in pest control in agricultural production.展开更多
The aboveground oligolectic bee,Heriades truncorum,is a particularly good model for studying the impact of pesticides on sexual communication,since some aspects of its mating behavior have previously been described.We...The aboveground oligolectic bee,Heriades truncorum,is a particularly good model for studying the impact of pesticides on sexual communication,since some aspects of its mating behavior have previously been described.We have tested(1)the interference of the pesticide flupyradifurone on male precopulatory behavior and male mating partner preferences,(2)the way that the pesticide interferes in male quality assessment by the female,and(3)the effects of the pesticide on the chemical compounds in the female cuticle.We exposed bees of both sexes to a sublethal concentration of flupyradifurone.Various behaviors were registered in a mating arena with two females(one unexposed and one exposed)and one male(either unexposed or exposed).Unexposed males were quicker to attempt to mate.Treatment also impacted precopulatory behavior and male quality assessment by females.Males approached unexposed females more quickly than insecticideexposed ones.Females exposed to insecticide produced lower amounts of some cuticular hydrocarbons(sex pheromone candidates)and appeared less choosy than unexposed females.Our findings suggest that insecticide exposure affects sexual communication,playing a role both in male preference and in male quality assessment by the female.展开更多
Effects of hexaflumuron at 10% lethal concentration （LC10） and LC25 on development and reproduction parameters of the diamondback moth, Plutella xylostella （Linnaeus, 1753） （Lep.： Yponomeutidae） were investigat...Effects of hexaflumuron at 10% lethal concentration （LC10） and LC25 on development and reproduction parameters of the diamondback moth, Plutella xylostella （Linnaeus, 1753） （Lep.： Yponomeutidae） were investigated. Estimated LC50, LC10 and LC25 values of leaf dip bioassay of hexaflumuron on the third instar larvae of the P xylostella were 1.48, 0.59 and 0.91 mg/L, respectively. Hexaflumuron decreased pupal weight in the parent generation at sublethal concentrations but in the offspring generation, this effect was not observed. Sublethal concentrations increased egg, first and second larval instar and pupa developmental time and shortened life span of adults, but did not change the third and fourth larval instars and pre-pupa developmental period. Also fecundity of females reduced significantly but hatchability of treatments and control were similar. Survival rate of pre-adult stages declined significantly at LC25 concentration. Reproduction parameters such as reproductive rate （R0） and intrinsic rate of increase in sublethal concentrations were significantly lower compared with control, but gross reproduction rate （GRR） at the LC10 concentration was increased and it could be hormoligosis. Also hexaflumuron significantly increased doubling time （Dt）. We conclude that the sublethal effects of hexaflumuron might exhibit significant effects on the population dynamics of P xylostella.展开更多
Aphis gossypii Glover （Hemiptera： Aphididae） is a key pest in cotton crops, notably owing to its increasing resistance to commonly used pesticides. Such resistance prompts for the development of integrated pest man...Aphis gossypii Glover （Hemiptera： Aphididae） is a key pest in cotton crops, notably owing to its increasing resistance to commonly used pesticides. Such resistance prompts for the development of integrated pest management （IPM） programs that include novel pesticides being effective against the aphid. In the present study, we assessed lethal and sublethal effects of cycloxaprid, a novel chiral neonicotinoid pesticide developed in China, on A. gossypii. The lethal concentration at 50% （LCs0） value of cycloxaprid on A. gossypii was estimated, using the dipping method, at 7.73 mg/L. The impact of a sublethal concentration （LC10） and a lethal concentration （LC40） of cycloxaprid on A. gossypii population growth and feeding behavior （using electrical penetration graph technique [EPG]）, and its transgenerational effect were further assessed. Adult longevity and fecundity significantly decreased after exposure to LEa0 or LC10 of cycloxaprid. Cycloxaprid with sublethal concentrations （especially LC40） had negative effects on phloem ingestion by A. gossypii. Additionally, the offspring of the adults exposed to LC40 of cycloxaprid had shorter nymphal development duration and adult longevity than the control, and those from LC10 and LC40 treatments had lower adult fecundity and net productive rate. We demonstrated that cycloxaprid is a pesticide showing both lethal and sublethal activities, and transgenerational effects on,4. gossypii; it may be useful for implementation in IPM programs against this aphid pest.展开更多
Effects of sublethal piperonyl butoxide （PB） on parasitization of Bemisia tabaci （Gennadius） （Hemiptera： Aleyrodidae） by Encarsia bimaculata Heraty et Polaszek （Hymenoptera： Aphelinidae） were evaluated both ...Effects of sublethal piperonyl butoxide （PB） on parasitization of Bemisia tabaci （Gennadius） （Hemiptera： Aleyrodidae） by Encarsia bimaculata Heraty et Polaszek （Hymenoptera： Aphelinidae） were evaluated both in cage and greenhouse experiments. When first, second and third instar B. tabaci nymphs were treated with PB, all but the first instar were significantly prolonged. Data indicated that sublethal PB could improve E. bimaculata parasitism rates without influencing parasitoid eclosion rates. Prolonged development increased rates of parasitism by E. bimaculata, from 17.6% to 24.7% in cages, presumably by increasing the duration of host exposure. Sublethal PB combined with E. bimaculata as an integrated approach to control B. tabaci was evaluated using life table parameters under greenhouse conditions. Indices of population trend （I） calculated from life tables were estimated at 4.6 for B. tabaci exposed to PB and parasitoids compared to 14.1 with parasitoids alone and 23.5 in un- treated controls. The results showed that after PB was sprayed and parasitoids introduced, development ofB. tabaci was delayed and the peak of each stage was postponed. The older nymphal stage had highest mortality, primarily due to mortality caused by parasitism by E. bimaculata.展开更多
Non-myeloablative regimens for host conditioning have been widely used in clinical hematopoietic stem cell transplantation due to their reduced toxicity on the recipients. But a milder conditioning regimen may require...Non-myeloablative regimens for host conditioning have been widely used in clinical hematopoietic stem cell transplantation due to their reduced toxicity on the recipients. But a milder conditioning regimen may require a higher engrafting ability of donor stem cells in competing with endogenous stem cells. Thus, new strategies for enhancing the competitiveness of donor stem cells in non-myeloablative recipients would have important implications for current clinical stem cell trans- plantation. It is known that the absence of p18INK4C (p18) gene can enhance the self-renewal potential of hematopoietic stem cells (HSCs). We applied the approach of competitive bone marrow trans- plantation to evaluate the impact of p18 gene deletion on long-term engraftment of HSCs in sub- lethally irradiated hosts. We found that p18?/? HSCs had a significant advantage over wild-type HSCs during long-term engraftment in the mouse recipients that received a sub-lethal irradiation (5-Gy). The engraftment efficiency of p18?/? HSCs in the sub-lethally irradiated recipients was similar to that in the lethally irradiated (10-Gy) recipients. Our current study demonstrates that enhanced engraftment of donor HSCs in the absence of p18 does not strictly depend on the dose of irradiation used for host conditioning. Therefore, p18 might serve as a potential drug target for increasing the efficacy of stem cell transplant in the patients that are preconditioned with either a myeloablative or non-myeloablative regimen.展开更多
Insecticides are anthropogenic environmental stressors and also a common stressor for mosquito vectors.However,the use of insecticides is often guided by short-term efficacy,and the sublethal effect on their target or...Insecticides are anthropogenic environmental stressors and also a common stressor for mosquito vectors.However,the use of insecticides is often guided by short-term efficacy,and the sublethal effect on their target or nontarget species has long been ignored.Here,we analyzed how sublethal exposure of the promising vector-control bioinsecticide spinetoram to Aedes aegypti larvae alter adult performance and susceptibility to dengue virus(DENV)infection.We found that the surviving adult mosquitoes were significantly smaller and exhibited weaker blood-feeding capacity than control females,apart from the extended immature development period.In terms of reproductive potential,although the F_(0) generation produced a similar number of eggs and offspring during the first gonotrophic cycle,the survival rates of the F_(1) generations were significantly lower as compared to the control group,suggesting transgenerational sublethal effects on the F_(1) generation.Notably,surviving adult females had higher DENV-2 viral loads than the control group after spinetoram sublethal exposure.Mechanistically,transcriptomic analysis showed that inhibition of oxidative phosphorylation may function in stimulating DENV production in adult Ae.aegypti.In Aag2 cells,significant accumulation of apoptosis,mitochondrial reactive oxygen species production,and DENV-2 replication by spinetoram exposure consistently support our conclusion.Our study highlights the threat of sublethal spinetoram exposure on outbreaks of mosquito-borne viruses.展开更多
Mated 3-day-old female boll weevils, Anthonomus grandis grandis Boheman, reared from field-infested cotton （Gossypium hirsutum L.） squares were topically treated with an estimated LD50 of malathion （2μg） to asses...Mated 3-day-old female boll weevils, Anthonomus grandis grandis Boheman, reared from field-infested cotton （Gossypium hirsutum L.） squares were topically treated with an estimated LD50 of malathion （2μg） to assess its effects on fecundity, oviposition, and body fat condition. Two different food sources, cotton squares and artificial diet, were assessed in malathion-treated and nontreated （control） weevils. The LD50 caused ≈ 50% mortality in the square-fed malathion treatment, but the artificial diet-fed malathion-treated weevils were less susceptible. LD50 survivors fed on the squares produced ≥ 9 times more chorionated eggs in the ovaries and oviposited ≥ 19-fold more than survivors fed artificial diet, regardless of the malathion treatment. Boll weevils that survived a 2μg LD50 malathion and also fed squares were ≈4.5-fold leaner than diet-fed weevils. Our findings demonstrate that non-resistant boll weevils surviving a sublethal dose of malathion will reproduce without any delay or significant loss in fecundity, and the food source for which boll weevils are maintained when conducting these assays will directly affect the results. The significance of these findings and how they are related to the final stages of eradicating the boll weevil from the US are discussed.展开更多
基金supported by the National 863 Program of China(2012AA101502)the Special Fund for Agro-Scientific Research in the Public Interest, China (200903033)
文摘Sublethal effects of chlorantraniliprole to Helicoverpa armigera （Hiibner） larvae were evaluated through exposure of third instar larvae to the insecticide incorporated into an artificial diet. When larvae were fed on the insecticide-containing diet for 7 d, the LC10, LC20, LC40, and LC50values were 3.790, 7.977, 21.577, and 33.121 μg active ingredient L^-1, respectively. Chlorantraniliprole at sublethal concentrations significantly reduced the larval body mass, emergence ratio, adult longevity and egg hatching rate in both the parental and offspring generations. The pupation and copulation rate in the parental generation and the pupal mass in the offspring also strongly decreased. Reproduction was seriously disturbed in both the parental and offspring groups even when only one of the partners was exposed to chlorantraniliprole at larval stages. However, at the lowest concentration of exposure （LC^0）, offspring fecundity was strongly reduced only when both partners were exposed. The net reproductive rate （R0）, intrinsic rate of increase （rm）, and gross reproduction rate （GRR） at LC20, LC40 concentrations were significantly lower than that of the control. Post-exposure effects also included an extended larval developmental time and increased male proportion in both generations. The doubling time （Dt） at LC20, LC40 concentrations as well as gross reproduction rate （GRR） at LC10 concentration were also significantly increased. Chlorantraniliprole might have significant effects on H. armigera population dynamics even at sublethal concentrations on both parental and offspring generations.
基金supported by the National Natural Science Foundation of China(31801760 and 31871997)the Fundamental Research Funds for the Central Universities,China(2662019QD052)。
文摘The cotton aphid,Aphis gossypii Glover(Hemiptera:Aphididae),is an important insect pest of cotton crops worldwide.The objectives of this study were to determine the acute toxicity of afidopyropen and whether there are any effects of sublethal concentrations of afidopyropen on the biological characteristics of A.gossypii.The results showed that afidopyropen possesses high acute toxicity to adult A.gossypii with a 72 h LC_(50) value of 1.062 mg L^(–1).A sublethal concentration(LC_(10))of afidopyropen significantly decreased adult longevity,fecundity and oviposition days of female adults in both F0 and F1 generations.The total pre-adult survival of F_(1) progeny was also significantly reduced by 30%at the LC_(10) of afidopyropen.In addition,the nymph developmental time,pre-adult period,adult pre-reproductive period(APRP),and total pre-reproductive period(TPRP)of the F1 progeny were significantly prolonged compared with the control.Several population parameters,including the net reproductive rate(R_(0)),intrinsic rate of increase(r)and finite rate of increase(λ)of F_(1) progeny were significantly decreased by a sublethal afidopyropen concentration exposure.These results indicated that sublethal concentration of afidopyropen can significantly suppress A.gossypii population growth.It would be useful for assessing the overall effects of afidopyropen on A.gossypii.
基金the Huazhong Agricultural University Scientific & Technological Self-Innovation Foundation, China (2009SC001)
文摘Metaflumizone is a novel sodium channel blocker insecticide, which has been registered for controling the diamondback moth （DBM）, Plutella xylostella （Lepidoptera： Plutellidae） in China. It is unavoidable for DBMs to be exposed to sublethal dose of metaflumizone in brassicaceous vegetable field. Sublethal effects of metaflumizone at LC15 （1.06 mg L-1） and LCz5 （2.03 mg L-1） on the biological characteristics were investigated. Pupation rate, pupal period and pupal weight were significantly declined comparing with the control （P=0.05） when third instar larvae were exposed to LC15 and LC25 of metaflumizone. Comparing the control group to LC15 and LC25 treatment groups, there were significant differences in the development periods of eggs, first instar larvae, pupae and total preoviposition period. The peak of age-specific fecundity in LC15 and LC25 treatment groups was lagged behind control group. Mean values of intrinsic rate of increase （rm）, net reproductive rate （R0） and finite rate of increase （λ） observed from the LCl5 and LC25 treatment groups were lower than those from the control group. But mean values of gross reproduction rate （GRR） was not different. The mean generation time （T） of the treatment groups was prolonged. Whether sublethal doses of metaflumizone could stimulate reproduction in the long term needs further investigation on continuous generations.
基金financially supported by the Jiangsu Agricultural Scientific Self-innovation Fund,China (CX(15)1057)the Fund of Science and Technology of Jiangsu Province,China (BE2015342)the National Key Research and Development Program of China (2017YFD0200400 and 2016YFD0300706)
文摘The green miridbug,Cyrtorhinus lividipennis,is an important predator of the rice brown planthopper,Nilaparvata lugens.In this study,the selective toxicity of seven commercial biopesticides for C.lividipennis was examined under laboratory conditions; abamectin was the most selective to C.lividipennis,followed by matrine and azadirachtin.Veratridine,rotenone,Bacillus thuringiensis and Beauveria bassiana showed less selectivity for C.lividipennis.Subsequently,matrine,abamectin and azadirachtin were selected for sublethal assessments with respect to C.lividipennis due to their high toxicities to N.lugens.C.lividipennis treated with sublethal concentrations(LC10 and LC20) of the three biopesticides could distinguish volatiles released from healthy and N.lugens-infested plants indicating that the biopesticides tested did not affect the foraging ability of surviving miridbugs.Azadirachtin decreased the consumption capability of C.lividipennis when the densities of N.lugens were 20,30,40 and 50 insects per vial.Sublethal concentration treatment did not impact the pre-oviposition period or egg hatchability of C.lividipennis.However,the fecundity of C.lividipennis exposed to azadirachtin and abamectin increased by 27–41% compared to the untreated individuals.In summary,abamectin or matrine together with C.lividipennis could be considered an effective,sustainable pest management strategy for rice.
基金supported by the National Barley Industry Technology System of China(CARS-05)
文摘Sitobion avenae(F.) and Rhopalosiphum padi(L.) are two important pests of wheat in China.They typically coexist in fields during the late period of wheat growth.Sulfoxaflor is a novel sulfoximine insecticide that demonstrates broad-spectrum efficacy,especially in targeting sap-feeding insects.This study was carried out to investigate the sublethal effects of sulfoxaflor on the development,longevity,and reproduction of two species of wheat aphids.Our results showed that sublethal concentrations of sulfoxaflor did not cause significant effects on the fecundity or the longevity of the parent generation(F0 generation) of either S.avenae or R.padi.However,it caused transgenerational sublethal effects.For S.avenae,adult longevity of F1 generation was significantly decreased.No significant differences were observed on the population parameters of S.avenae in the F1 generation.For R.padi,the adult preoviposition period(APOP) and the total preoviposition period(TPOP) of F1 generation were significantly reduced.The mean generation time(T) was significantly reduced in the R.padi F1 generation.What’s more,the intrinsic rate of increase(rm) and the finite rate of increase(λ) were significantly increased in the R.padi F1 generation.Taken together,these results suggest that exposure to the LC25 of sulfoxafl had no effects on the parent generation of S.avenae or R.padi,but it reduced adult longevity of S.avenae as a negative effect and increased the rm and λ of R.padi in the first progeny generation,which may have an impact on the population dynamics of R.padi.
文摘The effects of sublethal doses （LD10：1.00 ng larval-1; LD30： 3.75 ng larva-1） of chlorfluazuron on number and size of developmental spermatocytes in pupal-testis during spermatogenesis of the common cutworm, Spodoptera litura （F.） are described. Chlorfluazuron was applied topically to newly-ecdysed fifth-instar larvae of S. litura under laboratory conditions. During first day of pupation, spermatids were the highest （3,430 ± 7）, however, elongated spermatocytes with mature sperm were the lowest （292 ± 16） in number in pupal-testis compared with other developing spermatocytes. During last day of pupation, elongated spermatocytes with mature sperm were the highest （3,581 ± 3）, however, spermatogonia were the lowest （86± 4） in number in pupal-testis compared with other developing spermatocytes. The number of spermatogonia, primary and secondary spermatocytes, spermatids and elongated cysts with mature sperm were increased during pupal-developmental days in the controls. However, their numbers were significantly reduced in LD10- and even more significantly reduced in LD30-treated pupal-testis compared with controls. Moreover, eupyrene sperm bundles were not present in pupal-testis. During pupal-developmental days, spermatids were the smallest （4.1 ± 0.9 dm in μm） and secondary spermatocytes were the largest （31.0 ± 1.8 dm in μm） in size compared with other developing spermatocytes. The sizes of the same developing spermatocytes were significantly reduced in LD10-treated and more significantly reduced in LD30-treated pupal-testis of S. litura compared with controls.
文摘Lead has been recognized as a high risk toxic for most organisms including human. The effects of Pb in non-mammalian vertebrates are oprly known, particularly in anuran amphibians. The purpose of this study was to determine the effect of this metal on some hematological parameters of adult Bufo arenarum. It was found that all parameters remained unaltered within normal ranges, with the exception of reticulocyte counts which was significantly increased compared to the in controls (3. 7% vs. 0. 2 % ). It is suggested that the selective change found in reticulocyte count might be considered as an early response of a biomarker to sublethal exposition of Bufo arenarum to lead.
文摘The time-course and dose-related action of amitraz (AMZ) on gut lipids of worker honeybees were examined over 3 hours following in vivo injections of 0.25, 0.5, 1 and 2 nmols of pesticide per bee. Significant decreases were observed at 30-45 min with 0.25 nmols per bee, for phospholipids, fatty acids, steroids and triacylglycerols. However increases were observed either later or with higher doses. The decreasing action observed with 0.25 nmol AMZ per bee was inhibited by simultaneous injections of the a antagonist phentolamine (from 0.25 to 2.0 nmols per bee). The toxicity of AMZ to honeybees thus likely involves the mobilization of lipids from the gut, via action of this formamidine pesticide on a-adrenoceptors.
文摘Chlorfluazuron is an insect growth regulator for controlling the major insect pests in crops. This paper describes the effects of sublethal doses （LD10：1.00 ng/larva; LD30：3.75 ng/larva） of chlorfluazuron on ovarioles during ovarian development and oogenesis of common cutworm, Spodoptera litura （F.）. It is a significant pest of cotton, tobacco and miscellaneous vegetables. The LDlo or LD3o was applied topically to the newly-ecdysed fifth-instars of S. litura under laboratory conditions. In controls, on 2nd day of adult emergence, the cell density in germarium was 1636 ± 9.17 nuclei/mm^2. It increased until 3rd day, i.e., 1829 ± 8.87 nuclei/mm^2 and decreased thereafter. In the LDloor LD-3o-treated insects, the patterns of the cell density was the same as in controls but values were significantly （P 〈 0.05） decreased in the LD10- and more in the LDa0-treated females compared with controls. In control, ovaries were normal type and had mature ova with an occasional one or two being absorbed. In LD10-treated females, ovaries had spaces in ovarioles and absorption of ova. In LD30-treated females, besides the spacing and absorption, sometimes only immature （germarium） ova were found.
文摘Chlorfluazuron is an insect growth regulator for controlling the major insect pests in crops. This paper describes the effects of sublethal doses （LD10：1.00 ng/larva; LD3o： 3.75 ng/larva） of chlorfluazuron on spermatogenesis in the adults of the common cutworm, Spodoptera litura （F.）. Chlorfluazuron was applied topically to the newly-ecdysed fifth-instars ofS. litura under laboratory conditions. The secondary spermatocytes, spermatids, elongated spermatocytes with mature sperm and eupyrene sperm bundles were present in testis of newly emerged, 1 and 2 day-old adults, but gradually decreased in their numbers in the controls. However, the spermatogonia were not present in newly emerged, 1 and 2 day-old adults. Moreover, primary spermatocytes were present （174 ± 4.0） in newly emerged adults, but not found in 1 and 2 day-old adults. In the testes of newly emerged LD10-treated adults, the numbers of eupyrene and apyrene sperm bundles were significantly reduced compared with controls, and even significantly reduced in LD30-treated adults compared with LDlo, however, their ratios were not affected. Moreover, the pattern of spermatogenesis was the same in LD10- and LD30-treated male adults compared with controls. Furthermore, numbers of developing spermatocytes were significantly reduced in the LD10 compared with controls, and even significantly reduced in LD30-treated male adults compared with LD10. In newly emerged adults, the width and length of elongated spermatocytes with mature sperm were significantly reduced in LDlo- and more significantly reduced in LD30-treated compared with controls of S. litura. In vas deferens of untreated pre- and newly emerged adult male, both eupyrene and apyrene sperm bundles were found, however, in treated pre-adult male, only apyrene sperm bundles and in treated newly emerged adult male, fe, w eupyrene and numerous apyrene sperm bundles were found. It is concluded that spermatogenesis was significantly affected by chlorfluazuron.
文摘The present study is on the haematological and hepatic responses of the African catfish fingerlings Clarias gariepinus to sublethal toxicity of industrial effluents(IE)from the environment of Ologe Lagoon,Lagos,Nigeria.The fish were cultured in five concentrations of industrial effluents:0%(control),5%,15%,25%,and 35%.Trials were carried out in triplicates for twelve(12)weeks.The culture system was a static renewable bioassay and was carried out in the fisheries laboratory of the Lagos State University,Ojo-Lagos.Weekly physico-chemical parameters:Temperature(°C),pH,conductivity(ppm)and dissolved oxygen(DO in mg/L)were measured in each treatment tank.Haematological parameters:packed cell volume(PCV),red blood cells(RBC),white blood cell(WBC),neutrophil and lymphocytes etc.,and hepatological alterations were measured after 12 weeks.The physico-chemical parameters showed that the pH ranged from 7.82±0.25~8.07±0.02.DO ranged from 1.92±0.66~4.43±1.24 mg/L.The conductivity values increased with increase in concentration of I.E.While the temperature difference remained insignificant with mean value range between 26.08±2.14~26.38±2.28.The DO showed significant differences at p<0.05.Though survival was 100%during the sublethal study,haematological results showed that C.gariepinus had PCV ranging from 13.0±1.7~27.7±0.6,RBC ranged from 4.7±0.6~9.1±0.1,and neutrophil ranged from 26.7±4.6~61.0±1.0 amongst others.The highest values of these parameters were obtained in the control and lowest at 35%.While the reverse effects were observed for WBC and lymphocytes,the liver shows normal liver cells in the control(0%),but at higher toxic levels,there were:vacoulation,destruction of the hepatic parenchyma,tissue becoming eosinophilic(i.e.tending towards Carcinogenicity)and severe disruption of the hepatic cord architecture.This study therefore shows that disposal of effluents into the aquatic environment affects the health of fishes by impairing normal hepatic functions and hindering vital physiological processes if exposure continues for a long period of time(sublethal effect).
基金Supported by the University Grants Commission,Govt.of India,New Delhi Project No.F.3-66/89(SR-Ⅱ).
文摘Histopathological alterations induced by the sublethal concentration of (0.03 ppm) mercuric chloride solution on the epidermis of the fresh-water catfish Heteropneuates fossilis have been studied. It induces slow but significant histopathological changes in the various cellular components of the epidermis. It induces vacuolization, necrosis and pycnosis of the nuclei of the epithelial cells which subsequently shed. Loosening of epithelial cells of the outermost and middle layers following degeneration of the intercellular material and widened intercellular spaces is another important alteration. Prolonged mercury treatment also causes a gradual decrease in staining intensity for sulphated glycosaminoglycans in the outer border of the most superficial layer epithelial cells. The glandular elements (club cells and mucocytes) also get affected, showing cyclic degeneration followed by regeneration.
基金supported by the National Natural Science Foundation of China(No.12261018)Youth Science and Technology Talent Growth Project of Guizhou Provincial Department of Education(KY[2018]341,KY[2018]157).
文摘Considering the influence of sublethal concentration of pesticides on pests and natural enemies,we propose a pest-management model with impulsive effect on chemical control and biological control strategies periodic spraying pesticide and releasing predatory natural enemies.By using the Floquet theory and the comparison theorem of impulsive differential equations,a sufficient condition for the global asymptotic stability of the pest-eradication periodic solution is obtained.The persistence of the system is further studied,and a sufficient condition for the persistence of the system is obtained.Finally,some numerical simulations are shown to verify our theoretical works.Our works indicate that the sublethal effects of insecticides and the release of predatory natural enemies play significant roles in pest control in agricultural production.
文摘The aboveground oligolectic bee,Heriades truncorum,is a particularly good model for studying the impact of pesticides on sexual communication,since some aspects of its mating behavior have previously been described.We have tested(1)the interference of the pesticide flupyradifurone on male precopulatory behavior and male mating partner preferences,(2)the way that the pesticide interferes in male quality assessment by the female,and(3)the effects of the pesticide on the chemical compounds in the female cuticle.We exposed bees of both sexes to a sublethal concentration of flupyradifurone.Various behaviors were registered in a mating arena with two females(one unexposed and one exposed)and one male(either unexposed or exposed).Unexposed males were quicker to attempt to mate.Treatment also impacted precopulatory behavior and male quality assessment by females.Males approached unexposed females more quickly than insecticideexposed ones.Females exposed to insecticide produced lower amounts of some cuticular hydrocarbons(sex pheromone candidates)and appeared less choosy than unexposed females.Our findings suggest that insecticide exposure affects sexual communication,playing a role both in male preference and in male quality assessment by the female.
文摘Effects of hexaflumuron at 10% lethal concentration （LC10） and LC25 on development and reproduction parameters of the diamondback moth, Plutella xylostella （Linnaeus, 1753） （Lep.： Yponomeutidae） were investigated. Estimated LC50, LC10 and LC25 values of leaf dip bioassay of hexaflumuron on the third instar larvae of the P xylostella were 1.48, 0.59 and 0.91 mg/L, respectively. Hexaflumuron decreased pupal weight in the parent generation at sublethal concentrations but in the offspring generation, this effect was not observed. Sublethal concentrations increased egg, first and second larval instar and pupa developmental time and shortened life span of adults, but did not change the third and fourth larval instars and pre-pupa developmental period. Also fecundity of females reduced significantly but hatchability of treatments and control were similar. Survival rate of pre-adult stages declined significantly at LC25 concentration. Reproduction parameters such as reproductive rate （R0） and intrinsic rate of increase in sublethal concentrations were significantly lower compared with control, but gross reproduction rate （GRR） at the LC10 concentration was increased and it could be hormoligosis. Also hexaflumuron significantly increased doubling time （Dt）. We conclude that the sublethal effects of hexaflumuron might exhibit significant effects on the population dynamics of P xylostella.
文摘Aphis gossypii Glover （Hemiptera： Aphididae） is a key pest in cotton crops, notably owing to its increasing resistance to commonly used pesticides. Such resistance prompts for the development of integrated pest management （IPM） programs that include novel pesticides being effective against the aphid. In the present study, we assessed lethal and sublethal effects of cycloxaprid, a novel chiral neonicotinoid pesticide developed in China, on A. gossypii. The lethal concentration at 50% （LCs0） value of cycloxaprid on A. gossypii was estimated, using the dipping method, at 7.73 mg/L. The impact of a sublethal concentration （LC10） and a lethal concentration （LC40） of cycloxaprid on A. gossypii population growth and feeding behavior （using electrical penetration graph technique [EPG]）, and its transgenerational effect were further assessed. Adult longevity and fecundity significantly decreased after exposure to LEa0 or LC10 of cycloxaprid. Cycloxaprid with sublethal concentrations （especially LC40） had negative effects on phloem ingestion by A. gossypii. Additionally, the offspring of the adults exposed to LC40 of cycloxaprid had shorter nymphal development duration and adult longevity than the control, and those from LC10 and LC40 treatments had lower adult fecundity and net productive rate. We demonstrated that cycloxaprid is a pesticide showing both lethal and sublethal activities, and transgenerational effects on,4. gossypii; it may be useful for implementation in IPM programs against this aphid pest.
基金Acknowledgments This research was supported by the China National Natural Science Foundation （30400292, 31071743）, National Basic Research Program of China （973 project 2006CB 102005, 948 project 2011 4 6 1） and Na- tional Department Public Benefit Research Foundation （201003065）.
文摘Effects of sublethal piperonyl butoxide （PB） on parasitization of Bemisia tabaci （Gennadius） （Hemiptera： Aleyrodidae） by Encarsia bimaculata Heraty et Polaszek （Hymenoptera： Aphelinidae） were evaluated both in cage and greenhouse experiments. When first, second and third instar B. tabaci nymphs were treated with PB, all but the first instar were significantly prolonged. Data indicated that sublethal PB could improve E. bimaculata parasitism rates without influencing parasitoid eclosion rates. Prolonged development increased rates of parasitism by E. bimaculata, from 17.6% to 24.7% in cages, presumably by increasing the duration of host exposure. Sublethal PB combined with E. bimaculata as an integrated approach to control B. tabaci was evaluated using life table parameters under greenhouse conditions. Indices of population trend （I） calculated from life tables were estimated at 4.6 for B. tabaci exposed to PB and parasitoids compared to 14.1 with parasitoids alone and 23.5 in un- treated controls. The results showed that after PB was sprayed and parasitoids introduced, development ofB. tabaci was delayed and the peak of each stage was postponed. The older nymphal stage had highest mortality, primarily due to mortality caused by parasitism by E. bimaculata.
基金partially supported by the Outstanding Award for Chinese Oversea Scholar by the National Natural Science Foundation of China(Grant No.30228011)the General Award of National Natural Science Foundation of China(Grant No.39970709).
文摘Non-myeloablative regimens for host conditioning have been widely used in clinical hematopoietic stem cell transplantation due to their reduced toxicity on the recipients. But a milder conditioning regimen may require a higher engrafting ability of donor stem cells in competing with endogenous stem cells. Thus, new strategies for enhancing the competitiveness of donor stem cells in non-myeloablative recipients would have important implications for current clinical stem cell trans- plantation. It is known that the absence of p18INK4C (p18) gene can enhance the self-renewal potential of hematopoietic stem cells (HSCs). We applied the approach of competitive bone marrow trans- plantation to evaluate the impact of p18 gene deletion on long-term engraftment of HSCs in sub- lethally irradiated hosts. We found that p18?/? HSCs had a significant advantage over wild-type HSCs during long-term engraftment in the mouse recipients that received a sub-lethal irradiation (5-Gy). The engraftment efficiency of p18?/? HSCs in the sub-lethally irradiated recipients was similar to that in the lethally irradiated (10-Gy) recipients. Our current study demonstrates that enhanced engraftment of donor HSCs in the absence of p18 does not strictly depend on the dose of irradiation used for host conditioning. Therefore, p18 might serve as a potential drug target for increasing the efficacy of stem cell transplant in the patients that are preconditioned with either a myeloablative or non-myeloablative regimen.
基金funded by the National Natural Science Foundation of China(82002166)the fellowship of China Postdoctoral Science Foundation(2020M672676)+3 种基金the Guangdong Project of Basic and Applied Basic Research(20201910240000150)funded by the National Natural Science Foundation of China(81902093)Guangzhou Science and Technology Project(202002030100)Funding from State Key Laboratory of Biocontrol(Sun Yat-sen University)(2020SKLBC-KF01).
文摘Insecticides are anthropogenic environmental stressors and also a common stressor for mosquito vectors.However,the use of insecticides is often guided by short-term efficacy,and the sublethal effect on their target or nontarget species has long been ignored.Here,we analyzed how sublethal exposure of the promising vector-control bioinsecticide spinetoram to Aedes aegypti larvae alter adult performance and susceptibility to dengue virus(DENV)infection.We found that the surviving adult mosquitoes were significantly smaller and exhibited weaker blood-feeding capacity than control females,apart from the extended immature development period.In terms of reproductive potential,although the F_(0) generation produced a similar number of eggs and offspring during the first gonotrophic cycle,the survival rates of the F_(1) generations were significantly lower as compared to the control group,suggesting transgenerational sublethal effects on the F_(1) generation.Notably,surviving adult females had higher DENV-2 viral loads than the control group after spinetoram sublethal exposure.Mechanistically,transcriptomic analysis showed that inhibition of oxidative phosphorylation may function in stimulating DENV production in adult Ae.aegypti.In Aag2 cells,significant accumulation of apoptosis,mitochondrial reactive oxygen species production,and DENV-2 replication by spinetoram exposure consistently support our conclusion.Our study highlights the threat of sublethal spinetoram exposure on outbreaks of mosquito-borne viruses.
文摘Mated 3-day-old female boll weevils, Anthonomus grandis grandis Boheman, reared from field-infested cotton （Gossypium hirsutum L.） squares were topically treated with an estimated LD50 of malathion （2μg） to assess its effects on fecundity, oviposition, and body fat condition. Two different food sources, cotton squares and artificial diet, were assessed in malathion-treated and nontreated （control） weevils. The LD50 caused ≈ 50% mortality in the square-fed malathion treatment, but the artificial diet-fed malathion-treated weevils were less susceptible. LD50 survivors fed on the squares produced ≥ 9 times more chorionated eggs in the ovaries and oviposited ≥ 19-fold more than survivors fed artificial diet, regardless of the malathion treatment. Boll weevils that survived a 2μg LD50 malathion and also fed squares were ≈4.5-fold leaner than diet-fed weevils. Our findings demonstrate that non-resistant boll weevils surviving a sublethal dose of malathion will reproduce without any delay or significant loss in fecundity, and the food source for which boll weevils are maintained when conducting these assays will directly affect the results. The significance of these findings and how they are related to the final stages of eradicating the boll weevil from the US are discussed.
