The histopathological effect of pentachlor,an organochlorine pesticide,on the gill and liver tissues of the African catfish(Clarias gariepinus)juvenile was carried out to investigate the toxicity of pentachlor when ad...The histopathological effect of pentachlor,an organochlorine pesticide,on the gill and liver tissues of the African catfish(Clarias gariepinus)juvenile was carried out to investigate the toxicity of pentachlor when administered on the test sample within concentrations of 0.073 mg/L,0.036 mg/L,0.024 mg/L and 0.018 mg/L and a control in those replicates was used.The fish were acclimatized for 7 days under laboratory conditions before exposure.Sixteen(16)troughs,each of seven(7)juvenile samples of length 2.3 cm and average weight of 10-15 g,were used for the study.Twelve(12)troughs exposed to varying concentrations of pentachlor were used as treatment samples while four(4)troughs served as control.The juveniles were exposed to sub-lethal concentrations for 21 days with a break at every 48 h.The gills and livers were collected for histological examination.Histological data revealed that at 0.1 m/L pentachlor concentration,the gills showed epithelial hyperplasia with heamorrhage in the central venous of the cartilaginous core with the lifting of the epithelia and hypertrophy at 0.2 mg/L.At 0.3 mg/L exposure,epithelia hyperplasia,dilation of the secondary lamellae occurred and severe deformation of the secondary gill lamellae at 0.4 mg/L.However,the control presented normal mucous and epithelial cells with normal secondary and primary gill lamellae.The liver sample treated with 0.1 mg/L showed complete vascular degeneration.Control sample revealed normal blood vessels,sinusoid vessels and hypatocystes.This showed that pentachlor can accumulate in the liver and potentially cause damage to tissue over time.展开更多
The potato tuberworm Phthorimaea operculella Zeller, is one of the most important potato pests worldwide including China. Several reports indicate that P. operculella could be controlled biologically by the use of ben...The potato tuberworm Phthorimaea operculella Zeller, is one of the most important potato pests worldwide including China. Several reports indicate that P. operculella could be controlled biologically by the use of beneficial fungus such as Beauveria bassiana(Bals.-Criv) Vuill. However, limited information is available under growing conditions in China. Thus, this study evaluated the sub-lethal effects of B. bassiana on the offspring of P. operculella by the age-stage, two-sex life table. First instar larva of P. operculella were treated with 1×107 conidia m L–1 of the fungus, and several biological parameters were evaluated. The fecundity, duration of the egg stage, all larval stages, pre-adult stage, and total pre-oviposition period, were significantly shorter than the control treatment. Offspring of treated parents, presented a net reproductive rate and mean generation time of 17.43 per day and 24.98 days, respectively, compared to 65.79 per day and 26.51 days for the untreated ones. This study provides basic information to help understanding the potential long-term effects of entomopathogenic fungi on P. operculella.展开更多
Lethal and sub-lethal effects of transgenic rice containing cry1Ac and CpTI genes on the pink stem borer, Sesamia inferens, were studied to collect information for ecological risk assessment on insect-resistance of tr...Lethal and sub-lethal effects of transgenic rice containing cry1Ac and CpTI genes on the pink stem borer, Sesamia inferens, were studied to collect information for ecological risk assessment on insect-resistance of transgenic rice. In vitro insect-feeding bioassays were conducted to evaluate the lethal and sub-lethal effects of transgenic rice lines （II YouKF6 and KF6） containing cry1Ac＋CpTI genes on S. inferens at four different growth stages, viz., seedling, tillering and elongation, booting, and milk and maturing. Transgenic rice at seedling stage showed significantly high lethal effect on S. inferens with the shortest lethal duration for 50 and 100% individuals and the highest corrected mortalities after feeding on transgenic lines at this stage for 3 and 6 d. Followed by tillering and elongation stage, 50 and 100% S. inferens were dead after feeding on transgenic lines at this stage for 4 and 10 d, respectively. Moreover, corrected mortalities for 6 d feeding on transgenic lines at this stage were significantly higher than that at booting, and milk and maturing stages. Lethal effect of KF6 on S. inferens decreased significantly at booting stage. Lethal duration for 50% S. inferens significantly extended and its corrected mortalities for 6 d feeding also declined remarkably. However, lethal effect of II YouKF6 on S. inferens did not decrease significantly at this stage. Transgenic rice at booting, and milk and maturing stages did not show significant lethal effect to S. inferens and it showed the longest lethal duration for 50% individuals and the lowest corrected mortalities for 3 and 6 d feeding. A few larvae of S. inferens could survive, pupate and emerge on these two transgenic lines at booting, and milk and maturing stages. Sub-lethal effect of two transgenic lines on S. inferens also differed significantly between different developmental stages. Continuously feeding on transgenic rice lines at seedling, and tillering and elongation stages delayed the development of larvae and pupae and decreased pupation rate, but no effect was observed on eclosion rate. Larval development was significantly inhibited after feeding on transgenic rice at booting stage, but no obvious effect was observed in pupal stage, pupation and eclosion rate. There were no significant differences for larval and pupal development, pupation, and eclosion rates between feeding on transgenic and control rice lines at milk and maturing stage. Larval and pupal weights significantly declined, but no influence was observed on fecundity when S. inferens infested on transgenic rice at any stage. These showed that there were significant differences in lethal and sub-lethal effects of transgenic rice on S. inferens among developmental stages, and the effects gradually decreased with the increase of growth stages of rice plant.展开更多
Specimens of Clarias gariepinus were treated with lethal(70,75,80,85,90,and 95 mg/L) and sub-lethal concentrations(8,12 and 16 mg/L) of uranyl acetate,a low-radiotoxicity uranium salt. The LC 50 value was registered a...Specimens of Clarias gariepinus were treated with lethal(70,75,80,85,90,and 95 mg/L) and sub-lethal concentrations(8,12 and 16 mg/L) of uranyl acetate,a low-radiotoxicity uranium salt. The LC 50 value was registered as 81.45 mg/L. The protein and glycogen concentrations in liver and muscles were decreased in the fish exposed to sub-lethal concentrations. The red blood cell(RBC) and white blood cell(WBC) counts,haemoglobin(Hb) concentration and haematocrit(Hct) values were decreased. Different blood indices like mean corpuscular volume(MCV),mean corpuscular haemoglobin(MCH) and mean corpuscular haemoglobin concentration(MCHC) were negatively affected. Level of plasma glucose was elevated whereas protein was decreased. The level of calcium concentration(Ca) was declined in the blood of exposed fish whereas magnesium(Mg) remains unchanged. The activity level of glutamic-oxaloacetic transaminase(GOT) and glutamic-pyruvic transaminase(GPT) was elevated in exposed fish. These effects were more pronounced in the last period of exposure and in higher concentrations. Results of the present study indicate that uranyl acetate has adverse effects on C larias gariepinus and causes changes in the biochemical and hematological parameters of the fish.展开更多
Different approaches were assessed in the development of a bioassay method that would provide data necessary to evaluate resistance of apple genotypes to the obliquebanded leafroller (OBLR) Choristoneura rosaceana (Ha...Different approaches were assessed in the development of a bioassay method that would provide data necessary to evaluate resistance of apple genotypes to the obliquebanded leafroller (OBLR) Choristoneura rosaceana (Harris). A leaf disc method used to evaluate the impact of pesticides on leafrollers resulted in high levels of leaf-abandonment of first and second instar larvae. Inserting leaf petioles into water soaked Oasis foam resulted in a significant reduction in overall leaf weight and diminished the appearance of leaf quality. When leaf petioles were inserted into water-filled Eppendorf vials, leaf weight increased and overall leaf quality appeared to be good. We opted to adopt this latter whole-leaf bioassay method, which though very time consuming, provided a robust assessment of OBLR life history parameters against different apple genotypes. Across all apple genotypes evaluated, male larvae developed faster than females to pupation as well as to adulthood, while females developed faster as pupae and were heavier than male pupae. OBLR larvae reared on leaves from different apple genotypes displayed significant variability in development time, pupal weight, larval survivorship, and number of offspring produced. We utilized three indices to characterize host acceptance, sub-lethal effects, and lethal effects of OBLR to apple genotypes. Our results indicated that ‘Lady’, ‘Viking’, and ‘Northern Spy’ show some of the highest levels of resistance against OBLR, while ‘Granny Smith’ was quite susceptible to OBLR and could be used in future studies identifying apple genotypes with relative resistance to OBLR.展开更多
Acinetobacter baumannii is one of the most prevalent pathogens in nosocomial infections and has been cause of concern in recent years because, it has presented multiresistance to antibiotics and besides can form biofi...Acinetobacter baumannii is one of the most prevalent pathogens in nosocomial infections and has been cause of concern in recent years because, it has presented multiresistance to antibiotics and besides can form biofilms on biotic and abiotic surfaces like tissues and medical devices. Therefore, the search for new alternatives of natural origin to inhibit biofilm formation is being conducted. In the present investigation, sub-lethal concentrations (5.61 mg/mL, 3.74 mg/mL and 1.87 mg/mL) of methanolic extract of Nothoscordum bivalve were evaluated, showing biofilm formation inhibition up to 40.8%, in one nosocomial isolated of A. baumannii by the microtiter biofilm formation assay using crystal violet. On the other hand, the concentrations of 5.61 mg/mL and 3.74 mg/mL, caused an overexpression (up to 15.4 times) in the genes involved in the formation of biofilm (abaI, bap and csuE);due to this, the interaction of the extract with the bacteria was analyzed by scanning electron microscopy (SEM) and cellular damage was observed in the structure and stability of biofilm.展开更多
Insecticides cause a range of sub-lethal effects on targeted insects, which are frequently detrimental to them. However, targeted insects are able to cope with insecti- cides within sub-lethal ranges, which vary with ...Insecticides cause a range of sub-lethal effects on targeted insects, which are frequently detrimental to them. However, targeted insects are able to cope with insecti- cides within sub-lethal ranges, which vary with their susceptibility. Here we assessed the response of three strains of the maize weevil Sitophilus zeamais Motschulsky （Coleoptera.＂ Curculionidae） to sub-lethal exposure to the pyrethoid insecticide cypermethrin. We ex- pected enzyme induction associated with cypermethrin resistance since it would aid the resistant insects in surviving such exposure. Lower respiration rate and lower activity were also expected in insecticide-resistant insects since these traits are also likely to favor survivorship under insecticide exposure. Curiously though, cypermethrin did not affect ac- tivity of digestive and energy metabolism enzymes, and even reduced the activity of some enzymes （particularly for cellulase and cysteine-proteinase activity in this case）. There was strain variation in response, which may be （partially） related to insecticide resistance in some strains. Sub-lethal exposure to cypermethrin depressed proteolytic and mainly cellulolytic activity in the exposed insects, which is likely to impair their fitness. However, such exposure did not affect respiration rate and walking behavior of the insects （except for the susceptible strain where walking activity was reduced）. Walking activity varies with strain and may minimize insecticide exposure, which should be a concern, particularly if associated with （physiological） insecticide resistance.展开更多
文摘The histopathological effect of pentachlor,an organochlorine pesticide,on the gill and liver tissues of the African catfish(Clarias gariepinus)juvenile was carried out to investigate the toxicity of pentachlor when administered on the test sample within concentrations of 0.073 mg/L,0.036 mg/L,0.024 mg/L and 0.018 mg/L and a control in those replicates was used.The fish were acclimatized for 7 days under laboratory conditions before exposure.Sixteen(16)troughs,each of seven(7)juvenile samples of length 2.3 cm and average weight of 10-15 g,were used for the study.Twelve(12)troughs exposed to varying concentrations of pentachlor were used as treatment samples while four(4)troughs served as control.The juveniles were exposed to sub-lethal concentrations for 21 days with a break at every 48 h.The gills and livers were collected for histological examination.Histological data revealed that at 0.1 m/L pentachlor concentration,the gills showed epithelial hyperplasia with heamorrhage in the central venous of the cartilaginous core with the lifting of the epithelia and hypertrophy at 0.2 mg/L.At 0.3 mg/L exposure,epithelia hyperplasia,dilation of the secondary lamellae occurred and severe deformation of the secondary gill lamellae at 0.4 mg/L.However,the control presented normal mucous and epithelial cells with normal secondary and primary gill lamellae.The liver sample treated with 0.1 mg/L showed complete vascular degeneration.Control sample revealed normal blood vessels,sinusoid vessels and hypatocystes.This showed that pentachlor can accumulate in the liver and potentially cause damage to tissue over time.
基金supported by the External Cooperation Program of Yunnan Province,China(2014IB002)
文摘The potato tuberworm Phthorimaea operculella Zeller, is one of the most important potato pests worldwide including China. Several reports indicate that P. operculella could be controlled biologically by the use of beneficial fungus such as Beauveria bassiana(Bals.-Criv) Vuill. However, limited information is available under growing conditions in China. Thus, this study evaluated the sub-lethal effects of B. bassiana on the offspring of P. operculella by the age-stage, two-sex life table. First instar larva of P. operculella were treated with 1×107 conidia m L–1 of the fungus, and several biological parameters were evaluated. The fecundity, duration of the egg stage, all larval stages, pre-adult stage, and total pre-oviposition period, were significantly shorter than the control treatment. Offspring of treated parents, presented a net reproductive rate and mean generation time of 17.43 per day and 24.98 days, respectively, compared to 65.79 per day and 26.51 days for the untreated ones. This study provides basic information to help understanding the potential long-term effects of entomopathogenic fungi on P. operculella.
基金funded by the National 973 Program of China (2007CB109204)the Major Projects of National Genetically Modified Organisms Breeding of China (2009ZX08011-007B, 2008ZX08011-001A)
文摘Lethal and sub-lethal effects of transgenic rice containing cry1Ac and CpTI genes on the pink stem borer, Sesamia inferens, were studied to collect information for ecological risk assessment on insect-resistance of transgenic rice. In vitro insect-feeding bioassays were conducted to evaluate the lethal and sub-lethal effects of transgenic rice lines （II YouKF6 and KF6） containing cry1Ac＋CpTI genes on S. inferens at four different growth stages, viz., seedling, tillering and elongation, booting, and milk and maturing. Transgenic rice at seedling stage showed significantly high lethal effect on S. inferens with the shortest lethal duration for 50 and 100% individuals and the highest corrected mortalities after feeding on transgenic lines at this stage for 3 and 6 d. Followed by tillering and elongation stage, 50 and 100% S. inferens were dead after feeding on transgenic lines at this stage for 4 and 10 d, respectively. Moreover, corrected mortalities for 6 d feeding on transgenic lines at this stage were significantly higher than that at booting, and milk and maturing stages. Lethal effect of KF6 on S. inferens decreased significantly at booting stage. Lethal duration for 50% S. inferens significantly extended and its corrected mortalities for 6 d feeding also declined remarkably. However, lethal effect of II YouKF6 on S. inferens did not decrease significantly at this stage. Transgenic rice at booting, and milk and maturing stages did not show significant lethal effect to S. inferens and it showed the longest lethal duration for 50% individuals and the lowest corrected mortalities for 3 and 6 d feeding. A few larvae of S. inferens could survive, pupate and emerge on these two transgenic lines at booting, and milk and maturing stages. Sub-lethal effect of two transgenic lines on S. inferens also differed significantly between different developmental stages. Continuously feeding on transgenic rice lines at seedling, and tillering and elongation stages delayed the development of larvae and pupae and decreased pupation rate, but no effect was observed on eclosion rate. Larval development was significantly inhibited after feeding on transgenic rice at booting stage, but no obvious effect was observed in pupal stage, pupation and eclosion rate. There were no significant differences for larval and pupal development, pupation, and eclosion rates between feeding on transgenic and control rice lines at milk and maturing stage. Larval and pupal weights significantly declined, but no influence was observed on fecundity when S. inferens infested on transgenic rice at any stage. These showed that there were significant differences in lethal and sub-lethal effects of transgenic rice on S. inferens among developmental stages, and the effects gradually decreased with the increase of growth stages of rice plant.
基金Supported by the Deanship of Scientific Research at King Saud University(No.PRG-1436-011)
文摘Specimens of Clarias gariepinus were treated with lethal(70,75,80,85,90,and 95 mg/L) and sub-lethal concentrations(8,12 and 16 mg/L) of uranyl acetate,a low-radiotoxicity uranium salt. The LC 50 value was registered as 81.45 mg/L. The protein and glycogen concentrations in liver and muscles were decreased in the fish exposed to sub-lethal concentrations. The red blood cell(RBC) and white blood cell(WBC) counts,haemoglobin(Hb) concentration and haematocrit(Hct) values were decreased. Different blood indices like mean corpuscular volume(MCV),mean corpuscular haemoglobin(MCH) and mean corpuscular haemoglobin concentration(MCHC) were negatively affected. Level of plasma glucose was elevated whereas protein was decreased. The level of calcium concentration(Ca) was declined in the blood of exposed fish whereas magnesium(Mg) remains unchanged. The activity level of glutamic-oxaloacetic transaminase(GOT) and glutamic-pyruvic transaminase(GPT) was elevated in exposed fish. These effects were more pronounced in the last period of exposure and in higher concentrations. Results of the present study indicate that uranyl acetate has adverse effects on C larias gariepinus and causes changes in the biochemical and hematological parameters of the fish.
文摘Different approaches were assessed in the development of a bioassay method that would provide data necessary to evaluate resistance of apple genotypes to the obliquebanded leafroller (OBLR) Choristoneura rosaceana (Harris). A leaf disc method used to evaluate the impact of pesticides on leafrollers resulted in high levels of leaf-abandonment of first and second instar larvae. Inserting leaf petioles into water soaked Oasis foam resulted in a significant reduction in overall leaf weight and diminished the appearance of leaf quality. When leaf petioles were inserted into water-filled Eppendorf vials, leaf weight increased and overall leaf quality appeared to be good. We opted to adopt this latter whole-leaf bioassay method, which though very time consuming, provided a robust assessment of OBLR life history parameters against different apple genotypes. Across all apple genotypes evaluated, male larvae developed faster than females to pupation as well as to adulthood, while females developed faster as pupae and were heavier than male pupae. OBLR larvae reared on leaves from different apple genotypes displayed significant variability in development time, pupal weight, larval survivorship, and number of offspring produced. We utilized three indices to characterize host acceptance, sub-lethal effects, and lethal effects of OBLR to apple genotypes. Our results indicated that ‘Lady’, ‘Viking’, and ‘Northern Spy’ show some of the highest levels of resistance against OBLR, while ‘Granny Smith’ was quite susceptible to OBLR and could be used in future studies identifying apple genotypes with relative resistance to OBLR.
文摘Acinetobacter baumannii is one of the most prevalent pathogens in nosocomial infections and has been cause of concern in recent years because, it has presented multiresistance to antibiotics and besides can form biofilms on biotic and abiotic surfaces like tissues and medical devices. Therefore, the search for new alternatives of natural origin to inhibit biofilm formation is being conducted. In the present investigation, sub-lethal concentrations (5.61 mg/mL, 3.74 mg/mL and 1.87 mg/mL) of methanolic extract of Nothoscordum bivalve were evaluated, showing biofilm formation inhibition up to 40.8%, in one nosocomial isolated of A. baumannii by the microtiter biofilm formation assay using crystal violet. On the other hand, the concentrations of 5.61 mg/mL and 3.74 mg/mL, caused an overexpression (up to 15.4 times) in the genes involved in the formation of biofilm (abaI, bap and csuE);due to this, the interaction of the extract with the bacteria was analyzed by scanning electron microscopy (SEM) and cellular damage was observed in the structure and stability of biofilm.
文摘Insecticides cause a range of sub-lethal effects on targeted insects, which are frequently detrimental to them. However, targeted insects are able to cope with insecti- cides within sub-lethal ranges, which vary with their susceptibility. Here we assessed the response of three strains of the maize weevil Sitophilus zeamais Motschulsky （Coleoptera.＂ Curculionidae） to sub-lethal exposure to the pyrethoid insecticide cypermethrin. We ex- pected enzyme induction associated with cypermethrin resistance since it would aid the resistant insects in surviving such exposure. Lower respiration rate and lower activity were also expected in insecticide-resistant insects since these traits are also likely to favor survivorship under insecticide exposure. Curiously though, cypermethrin did not affect ac- tivity of digestive and energy metabolism enzymes, and even reduced the activity of some enzymes （particularly for cellulase and cysteine-proteinase activity in this case）. There was strain variation in response, which may be （partially） related to insecticide resistance in some strains. Sub-lethal exposure to cypermethrin depressed proteolytic and mainly cellulolytic activity in the exposed insects, which is likely to impair their fitness. However, such exposure did not affect respiration rate and walking behavior of the insects （except for the susceptible strain where walking activity was reduced）. Walking activity varies with strain and may minimize insecticide exposure, which should be a concern, particularly if associated with （physiological） insecticide resistance.
