In the present investigation various bioassays were conducted to evaluate the anti-termite efficacy of plant latex based formulations to control population of Indian white termite in subtropical soil. Results reveal t...In the present investigation various bioassays were conducted to evaluate the anti-termite efficacy of plant latex based formulations to control population of Indian white termite in subtropical soil. Results reveal that crude latex, its fractions and combinatorial fractions have shown very high toxicity against O. obesus. The LD50 values for different latex fractions of 24 h were in a range of 5.0-17.613 μg/mg while combined mixtures of Calotropis procera have shown synergistic activity against termites and caused comparably high mortality with LD50 1.987-6.016 μg/mg. The mortality rate was found dose and time dependent as it was found to be increased with an increase in dose and exposure period. In olfactometry tests, C. procera latex solvent fractions have shown significant repellency at a very low dose 0.010-0.320 μg/mg. Interestingly, solvent fractions have significantly repelled large numbers of worker termites due to volatile action of active components of latex and different additives. ED50 values obtained in crude latex were 0.121 μg/mg body weights while combinatorial formulations have shown ED50 in between 0.015-0.036 μg/mg. Statistical analysis of repelled and un-repelled termites gave a low Chi-square value (X2 value = 0.890) which is an indicator of independence of repellent action in randomly selected termite groups. In field experiments pre-soaked cotton threads impregnated with Calotropis procera crude latex were tagged around tree trunks of Tectona grandis provided a wider protection against O. obesus. By employing these pre-coated threads, termite infestation and tunneling activity were significantly decreased (p Calotropis procera possesses enough anti-termite potential against Indian white termite, O. obesus population. If used these, formulations may also provide wide a range of control against other kinds of pests including house hold, medical and veterinary. However, Calotropis procera latex based formulations can be recommended for effective control of termites in high infestation areas by applying spray, or in form of poison baits or as fumigant in pure form.展开更多
In the present investigation, various bioassays were conducted to evaluate the alteration in levels of various enzymes i.e. alkaline phosphatase, acid phosphatase, glutamate oxaloacetate transaminase, glutamate pyruva...In the present investigation, various bioassays were conducted to evaluate the alteration in levels of various enzymes i.e. alkaline phosphatase, acid phosphatase, glutamate oxaloacetate transaminase, glutamate pyruvate transaminase and acetylcholinesterase. For this purpose worker termites were treated with sub-lethal doses of 40% and 80% of 24 hrs LD<sub>50</sub> of latex-based combinatorial formulations and observations were taken at 4 hours intervals up to 24 hours. Ficus benghalensis crude latex and its combinatorial mixtures, like C-MLT-A, CU-MLT-A, AQ-MLT, P-MLT and EA-MLT significantly altered the level of enzymes in Odontotermes obesus and this effect found time and dose-dependent. Reduction or increase in enzymes was calculated by using the corresponding control. The maximum decrease in acid phosphatase level was observed at 16 h when termites were treated with 80% of LD<sub>50</sub> of B-MLT-B and P-MLT i.e. 82.84% at 16 h of treatment. A similar dose caused a very slight decrease in glutamate pyruvate transaminase at 4 h of treatment but with the increase in time. Further decrease was noted in other successive treatments that were significant at p > 0.05. Similarly, 40% and 80% of LD<sub>50</sub> of the C-MLT-B mixture caused significant (p > 0.05) decrease in alkaline phosphatase and acid phosphatase level at 16 h treatment i.e. 93.42%, 89.46% and 95.89%, 88.17% respectively. The level of acetylcholinesterase was also found to be decreased when termites were treated with 40% and 80% of LD<sub>50</sub> of C-MLT-B mixture i.e. 92.72% and 97.27% respectively. All the above alterations noted in levels of various enzymes confirm the action of latex ingredients on worker termites that were anti-feedant or deterrent types. These ingredients can be used to control not only termites but also other phytophagous insects.展开更多
In present investigation, various bio-molecular parameters i.e. glycogen, protein, amino acid, DNA, RNA and lipid, were determined for evaluation of anti-termite efficacy of Tagetes erecta essential oil based combinat...In present investigation, various bio-molecular parameters i.e. glycogen, protein, amino acid, DNA, RNA and lipid, were determined for evaluation of anti-termite efficacy of Tagetes erecta essential oil based combinatorial formulations against Indian white termite Odontotermes obesus. For this purpose, 40% and 80% of 24 hrs of LD50 values of various formulations were provided for treatment of termite workers. Observations were taken at 4 hrs time interval up to 16 hrs to know inhibitory activity of these combinatorial mixtures on termite species Odontotermes obesus. Significant (p > 0.05) alterations were observed in the level above mentioned bio-molecules when termites were treated with different combinatorial essential oils ingredients of Citrus maxima. Combinatorial mixtures of Tagetes erecta essential oils have shown synergistic activity against termites. This study will provide an overall sustainable way to termite control in crop field, gardens and houses. It also suggests use of essential oils as better alternative of synthetic termiticides as these are safer for environmental and human health.展开更多
Plant essential oils and their constituents have proven to be very effective against insects, especially termites. They are the best alternative to synthetic pesticides that are harmless to the environment and human h...Plant essential oils and their constituents have proven to be very effective against insects, especially termites. They are the best alternative to synthetic pesticides that are harmless to the environment and human health. In the present study, different enzymes, namely alkaline phosphatase, acid phosphatase, glutamate-oxaloacetate transaminase, glutamate-pyruvate transaminase and acetylcholinesterase, were evaluated in Indian termite Odontotermes obesus in a combination preparation based on Tagetes erecta essential oil. For the study of anti-termite effects against worker termites were treated topically with 40% and 80% of the 24-hour LD50 values of various combination formulations. Subsequent bioassays at 40% and 80% of LD50 of combinatorial preparations S-AST-A, S-AST-B, and S-AST-C resulted in a significant (p > 0.05) decrease in glutamate-oxaloacetate transaminase. After 16 hours of treatment, they were 87.92%, 80.17%, 89.30%, 79.17%, 81.92% and 73.17% respectively. In vivo exposures of 40% and 80% of the LD50 of the combination formulation caused a highly significant (p > 0.05) reduction (p > 0.05) of all test enzymes tested compared to controls. The effects of different oil formulations exhibited time- and dose-dependent responses, resulting in physiological changes in the concentrations of various enzymes. The combined mixture of Tagetes erecta essential oils has significantly better anti-termite ability compared to inorganic insecticides. Findings from this study will help support termite control in fields, gardens and homes in a sustainable way, without the downsides of insecticide resistance and pollution. These could potentially be used to produce commercial formulations for use against pests.展开更多
In the present study, Citrus maxima essential crude oil extract was used to prepare combinatorial formulations and workers of Indian white termite Odontotermes obesus were treated topically with 40% and 80% of 24 hr L...In the present study, Citrus maxima essential crude oil extract was used to prepare combinatorial formulations and workers of Indian white termite Odontotermes obesus were treated topically with 40% and 80% of 24 hr LD50 values of these formulations. In subsequent bioassays levels of various enzymes i.e. alkaline phosphatase, acid phosphatase, glutamate oxaloacetate transaminase, glutamate pyruvate transaminase and acetylcholinesterase were evaluated to determine the anti-termite efficacy of Citrus maxima essential oil based combinatorial formulations. S-RET-A, S-RET-B and S-RET-C caused significant (p > 0.05) decrease in glutamate oxaloacetate transaminase i.e. 87.47%, 86.81% and 81.77% & 82.04%, 79.39% and 74.75% respectively at 16 h treatment. In vivo exposure of 40% and 80% of LD<sub>50</sub> of combinatorial formulations caused very significant (p > 0.05) reduction in all the test enzymes i.e. alkaline phosphatase, acid phosphatase, glutamate oxaloacetate transaminase and glutamate pyruvate transaminase expect acetylcholinesterase levels after 16 h all tested treatments in comparison to control. Both dose-response and time period were found important in physiological alteration in levels of various enzymes. Combinatorial mixtures of Citrus essential oils have shown synergistic activity against termites. The research findings of the present study would help termite control in crop fields, gardens and houses in a sustainable way.展开更多
Essential oils are better alternative for synthetic termiticides with the inherent resistance by insects, environmental and health effects on humans. In present investigation, various bio-molecules i.e. glycogen, prot...Essential oils are better alternative for synthetic termiticides with the inherent resistance by insects, environmental and health effects on humans. In present investigation, various bio-molecules i.e. glycogen, protein, amino acid, DNA, RNA and lipid were evaluated to determine the anti-termite efficacy of Citrus maxima essential oil based combinatorial formulations against Indian white termite Odontotermes obesus. For this purpose, termites were treated topically with 40% and 80% of 24 hr LD<sub>50</sub> values of various combinatorial formulations. A significant (p > 0.05) alteration was noted in all the above biomolecules at various time intervals. Both dose response and time period was found important in physiological alteration in levels of various bio-molecules. Combinatorial mixtures of Citrus essential oils have shown synergistic activity against termites. The research outcomes of present investigation would help to open sustainable way to termite control in crop field, gardens and houses.展开更多
In present investigation, various bioassays were conducted to evaluate the alteration in levels of certain biomolecules, such as glycogen, protein, amino acid, DNA, RNA and lipids. For this purpose, worker termites we...In present investigation, various bioassays were conducted to evaluate the alteration in levels of certain biomolecules, such as glycogen, protein, amino acid, DNA, RNA and lipids. For this purpose, worker termites were treated with sub-lethal dose 40% and 80% of 24 hrs LD<sub>50</sub> values and observations were taken at 4 hrs interval up to 24 hrs. Crude latex and its combinatorial mixtures, like S-MLT-A, B-MLT-A, C-MLT-A, CU-MLT-A, AQ-MLT significantly altered level of bio-molecules in Odontotermes obesus. This effect was found time and dose dependent. Reduction or increase in biomolecules was calculated by using corresponding control. Maximum decrease in glycogen level was observed at 16 h when termites were treated with 80% of LD<sub>50</sub> of Ficus benghalensis aqueous extract i.e. 56.88% at 16 h of treatment. A similar dose caused very slight decrease in lipid contents at 4 h of treatment but it was found further significantly (p > 0.05) decreased in other successive treatments. 40% and 80% of LD<sub>50</sub> of C-MLT-B mixture caused significant (p > 0.05) decrease in DNA and RNA level at 16 h treatment. The level of DNA and RNA level was recorded 83.90%, 90.18% and 85.42% and 74.05% respectively. Similarly, total proteins were also found to be decreased with 40% and 80% of LD<sub>50</sub> of C-MLT-B mixture i.e. 71.47% and 66.45% respectively. All these alterations found in levels of various bio-molecules confirm the action of latex ingredients on worker termites that was antifeedant or deterrent types. These ingredients can be used to control not only termites but also other phytophagous insects in a sustainable and eco-friendly way.展开更多
Methane (CH4), carbon dioxide (CO2) and nitrous oxide (N2)O) are greenhouse gases (GHGs) which cause global warming. Natural sources of GHGs include wetlands and termites. Previous studies have quantified GHG emission...Methane (CH4), carbon dioxide (CO2) and nitrous oxide (N2)O) are greenhouse gases (GHGs) which cause global warming. Natural sources of GHGs include wetlands and termites. Previous studies have quantified GHG emissions from upland termites and no study has reported GHG emissions from seasonal wetlands (dambo) located termite mounds. The objective of this study was to evaluate the effect of dambo catena position on termite mound distribution and GHG emissions. It was hypothesized that mound density and GHG emissions from Odontotermes transvaalensis mounds, vary with catena position. The evaluated catena positions were margin, mid-slope, lower slope and bottom. Mound density was significantly lower in the bottom when compared to the other catena positions. The mean GHG fluxes were 88 μg m2 hr-1, 0.78 mg m2 hr-1 and 1361 mg m2 hr-1 for N2) O, CH4 and CO2 respectively. Fluxes varied with catena position and were 0.48, 0.72, 1.35 and 0.79 mg m-2 hr-1 for CH4 , and 1173.7, 1440.7, 1798.7 and 922.8 mg m-2 hr-1 for CO2 in the margin, mid-slope, lower slope and the bottom catena position respectively. For N2) O, there were no significant differences between catena positions. It was concluded that dambo located Odontotermes transvaalensis termite mounds are an important source of GHGs, and emissions varied with catena position for CO2 and CH4.展开更多
Chemical investigations of the termite-associated Streptomyces tanashiensis BYF-112 resulted in the discovery of four novel alkaloid derivatives: vegfrecines A and B(1 and 2), exfoliazone A(3), and venezueline H(7), i...Chemical investigations of the termite-associated Streptomyces tanashiensis BYF-112 resulted in the discovery of four novel alkaloid derivatives: vegfrecines A and B(1 and 2), exfoliazone A(3), and venezueline H(7), in addition to nine known metabolites(4-6, 8-13). The structures of these compounds were elucidated through comprehensive spectroscopic analysis and comparison with existing literature data. Antibacterial assays revealed that viridomycin A(11) exhibited potent antibacterial activity against Staphylococcus aureus, with a zone of inhibition(ZOI) of 12.67 mm, in comparison to a ZOI of 17.67 mm for the positive control gentamicin sulfate. Viridomycin A(11) showed moderate activity against Micrococcus tetragenus and Pseudomonas syringae pv. actinidae, with ZOI values of 15.50 and 14.33 mm, respectively, which were inferior to those of gentamicin sulfate(34.67 and 24.00mm). Viridomycin F(12) also exhibited moderate antibacterial effects against S. aureus, M. tetragenus, and P. syringae pv. actinidae,with ZOI values of 8.33, 16.50, and 10.83 mm, respectively. Cytotoxicity assays demonstrated that viridobruunine A(5), exfoliazone(6), viridomycin A(11), and X-14881E(13) exhibited significant cytotoxicity against human malignant melanoma(A375), ovarian cancer(SKOV-3), and gastric cancer(MGC-803) cell lines, with IC_(50) values ranging from 4.61 to 19.28 μmol·L^(-1). Furthermore, bioinformatic analysis of the complete genome of S. tanashiensis suggested a putative biosynthetic gene cluster(BGC) responsible for the production of compounds 1-12. These findings indicate that the secondary metabolites of insect-associated S. tanashiensis BYF-112hold promise as potential sources of novel antibacterial and anticancer agents.展开更多
文摘In the present investigation various bioassays were conducted to evaluate the anti-termite efficacy of plant latex based formulations to control population of Indian white termite in subtropical soil. Results reveal that crude latex, its fractions and combinatorial fractions have shown very high toxicity against O. obesus. The LD50 values for different latex fractions of 24 h were in a range of 5.0-17.613 μg/mg while combined mixtures of Calotropis procera have shown synergistic activity against termites and caused comparably high mortality with LD50 1.987-6.016 μg/mg. The mortality rate was found dose and time dependent as it was found to be increased with an increase in dose and exposure period. In olfactometry tests, C. procera latex solvent fractions have shown significant repellency at a very low dose 0.010-0.320 μg/mg. Interestingly, solvent fractions have significantly repelled large numbers of worker termites due to volatile action of active components of latex and different additives. ED50 values obtained in crude latex were 0.121 μg/mg body weights while combinatorial formulations have shown ED50 in between 0.015-0.036 μg/mg. Statistical analysis of repelled and un-repelled termites gave a low Chi-square value (X2 value = 0.890) which is an indicator of independence of repellent action in randomly selected termite groups. In field experiments pre-soaked cotton threads impregnated with Calotropis procera crude latex were tagged around tree trunks of Tectona grandis provided a wider protection against O. obesus. By employing these pre-coated threads, termite infestation and tunneling activity were significantly decreased (p Calotropis procera possesses enough anti-termite potential against Indian white termite, O. obesus population. If used these, formulations may also provide wide a range of control against other kinds of pests including house hold, medical and veterinary. However, Calotropis procera latex based formulations can be recommended for effective control of termites in high infestation areas by applying spray, or in form of poison baits or as fumigant in pure form.
文摘In the present investigation, various bioassays were conducted to evaluate the alteration in levels of various enzymes i.e. alkaline phosphatase, acid phosphatase, glutamate oxaloacetate transaminase, glutamate pyruvate transaminase and acetylcholinesterase. For this purpose worker termites were treated with sub-lethal doses of 40% and 80% of 24 hrs LD<sub>50</sub> of latex-based combinatorial formulations and observations were taken at 4 hours intervals up to 24 hours. Ficus benghalensis crude latex and its combinatorial mixtures, like C-MLT-A, CU-MLT-A, AQ-MLT, P-MLT and EA-MLT significantly altered the level of enzymes in Odontotermes obesus and this effect found time and dose-dependent. Reduction or increase in enzymes was calculated by using the corresponding control. The maximum decrease in acid phosphatase level was observed at 16 h when termites were treated with 80% of LD<sub>50</sub> of B-MLT-B and P-MLT i.e. 82.84% at 16 h of treatment. A similar dose caused a very slight decrease in glutamate pyruvate transaminase at 4 h of treatment but with the increase in time. Further decrease was noted in other successive treatments that were significant at p > 0.05. Similarly, 40% and 80% of LD<sub>50</sub> of the C-MLT-B mixture caused significant (p > 0.05) decrease in alkaline phosphatase and acid phosphatase level at 16 h treatment i.e. 93.42%, 89.46% and 95.89%, 88.17% respectively. The level of acetylcholinesterase was also found to be decreased when termites were treated with 40% and 80% of LD<sub>50</sub> of C-MLT-B mixture i.e. 92.72% and 97.27% respectively. All the above alterations noted in levels of various enzymes confirm the action of latex ingredients on worker termites that were anti-feedant or deterrent types. These ingredients can be used to control not only termites but also other phytophagous insects.
文摘In present investigation, various bio-molecular parameters i.e. glycogen, protein, amino acid, DNA, RNA and lipid, were determined for evaluation of anti-termite efficacy of Tagetes erecta essential oil based combinatorial formulations against Indian white termite Odontotermes obesus. For this purpose, 40% and 80% of 24 hrs of LD50 values of various formulations were provided for treatment of termite workers. Observations were taken at 4 hrs time interval up to 16 hrs to know inhibitory activity of these combinatorial mixtures on termite species Odontotermes obesus. Significant (p > 0.05) alterations were observed in the level above mentioned bio-molecules when termites were treated with different combinatorial essential oils ingredients of Citrus maxima. Combinatorial mixtures of Tagetes erecta essential oils have shown synergistic activity against termites. This study will provide an overall sustainable way to termite control in crop field, gardens and houses. It also suggests use of essential oils as better alternative of synthetic termiticides as these are safer for environmental and human health.
文摘Plant essential oils and their constituents have proven to be very effective against insects, especially termites. They are the best alternative to synthetic pesticides that are harmless to the environment and human health. In the present study, different enzymes, namely alkaline phosphatase, acid phosphatase, glutamate-oxaloacetate transaminase, glutamate-pyruvate transaminase and acetylcholinesterase, were evaluated in Indian termite Odontotermes obesus in a combination preparation based on Tagetes erecta essential oil. For the study of anti-termite effects against worker termites were treated topically with 40% and 80% of the 24-hour LD50 values of various combination formulations. Subsequent bioassays at 40% and 80% of LD50 of combinatorial preparations S-AST-A, S-AST-B, and S-AST-C resulted in a significant (p > 0.05) decrease in glutamate-oxaloacetate transaminase. After 16 hours of treatment, they were 87.92%, 80.17%, 89.30%, 79.17%, 81.92% and 73.17% respectively. In vivo exposures of 40% and 80% of the LD50 of the combination formulation caused a highly significant (p > 0.05) reduction (p > 0.05) of all test enzymes tested compared to controls. The effects of different oil formulations exhibited time- and dose-dependent responses, resulting in physiological changes in the concentrations of various enzymes. The combined mixture of Tagetes erecta essential oils has significantly better anti-termite ability compared to inorganic insecticides. Findings from this study will help support termite control in fields, gardens and homes in a sustainable way, without the downsides of insecticide resistance and pollution. These could potentially be used to produce commercial formulations for use against pests.
文摘In the present study, Citrus maxima essential crude oil extract was used to prepare combinatorial formulations and workers of Indian white termite Odontotermes obesus were treated topically with 40% and 80% of 24 hr LD50 values of these formulations. In subsequent bioassays levels of various enzymes i.e. alkaline phosphatase, acid phosphatase, glutamate oxaloacetate transaminase, glutamate pyruvate transaminase and acetylcholinesterase were evaluated to determine the anti-termite efficacy of Citrus maxima essential oil based combinatorial formulations. S-RET-A, S-RET-B and S-RET-C caused significant (p > 0.05) decrease in glutamate oxaloacetate transaminase i.e. 87.47%, 86.81% and 81.77% & 82.04%, 79.39% and 74.75% respectively at 16 h treatment. In vivo exposure of 40% and 80% of LD<sub>50</sub> of combinatorial formulations caused very significant (p > 0.05) reduction in all the test enzymes i.e. alkaline phosphatase, acid phosphatase, glutamate oxaloacetate transaminase and glutamate pyruvate transaminase expect acetylcholinesterase levels after 16 h all tested treatments in comparison to control. Both dose-response and time period were found important in physiological alteration in levels of various enzymes. Combinatorial mixtures of Citrus essential oils have shown synergistic activity against termites. The research findings of the present study would help termite control in crop fields, gardens and houses in a sustainable way.
文摘Essential oils are better alternative for synthetic termiticides with the inherent resistance by insects, environmental and health effects on humans. In present investigation, various bio-molecules i.e. glycogen, protein, amino acid, DNA, RNA and lipid were evaluated to determine the anti-termite efficacy of Citrus maxima essential oil based combinatorial formulations against Indian white termite Odontotermes obesus. For this purpose, termites were treated topically with 40% and 80% of 24 hr LD<sub>50</sub> values of various combinatorial formulations. A significant (p > 0.05) alteration was noted in all the above biomolecules at various time intervals. Both dose response and time period was found important in physiological alteration in levels of various bio-molecules. Combinatorial mixtures of Citrus essential oils have shown synergistic activity against termites. The research outcomes of present investigation would help to open sustainable way to termite control in crop field, gardens and houses.
文摘In present investigation, various bioassays were conducted to evaluate the alteration in levels of certain biomolecules, such as glycogen, protein, amino acid, DNA, RNA and lipids. For this purpose, worker termites were treated with sub-lethal dose 40% and 80% of 24 hrs LD<sub>50</sub> values and observations were taken at 4 hrs interval up to 24 hrs. Crude latex and its combinatorial mixtures, like S-MLT-A, B-MLT-A, C-MLT-A, CU-MLT-A, AQ-MLT significantly altered level of bio-molecules in Odontotermes obesus. This effect was found time and dose dependent. Reduction or increase in biomolecules was calculated by using corresponding control. Maximum decrease in glycogen level was observed at 16 h when termites were treated with 80% of LD<sub>50</sub> of Ficus benghalensis aqueous extract i.e. 56.88% at 16 h of treatment. A similar dose caused very slight decrease in lipid contents at 4 h of treatment but it was found further significantly (p > 0.05) decreased in other successive treatments. 40% and 80% of LD<sub>50</sub> of C-MLT-B mixture caused significant (p > 0.05) decrease in DNA and RNA level at 16 h treatment. The level of DNA and RNA level was recorded 83.90%, 90.18% and 85.42% and 74.05% respectively. Similarly, total proteins were also found to be decreased with 40% and 80% of LD<sub>50</sub> of C-MLT-B mixture i.e. 71.47% and 66.45% respectively. All these alterations found in levels of various bio-molecules confirm the action of latex ingredients on worker termites that was antifeedant or deterrent types. These ingredients can be used to control not only termites but also other phytophagous insects in a sustainable and eco-friendly way.
文摘Methane (CH4), carbon dioxide (CO2) and nitrous oxide (N2)O) are greenhouse gases (GHGs) which cause global warming. Natural sources of GHGs include wetlands and termites. Previous studies have quantified GHG emissions from upland termites and no study has reported GHG emissions from seasonal wetlands (dambo) located termite mounds. The objective of this study was to evaluate the effect of dambo catena position on termite mound distribution and GHG emissions. It was hypothesized that mound density and GHG emissions from Odontotermes transvaalensis mounds, vary with catena position. The evaluated catena positions were margin, mid-slope, lower slope and bottom. Mound density was significantly lower in the bottom when compared to the other catena positions. The mean GHG fluxes were 88 μg m2 hr-1, 0.78 mg m2 hr-1 and 1361 mg m2 hr-1 for N2) O, CH4 and CO2 respectively. Fluxes varied with catena position and were 0.48, 0.72, 1.35 and 0.79 mg m-2 hr-1 for CH4 , and 1173.7, 1440.7, 1798.7 and 922.8 mg m-2 hr-1 for CO2 in the margin, mid-slope, lower slope and the bottom catena position respectively. For N2) O, there were no significant differences between catena positions. It was concluded that dambo located Odontotermes transvaalensis termite mounds are an important source of GHGs, and emissions varied with catena position for CO2 and CH4.
基金supported by the Natural Science Funds for Distinguished Young Scholars of Anhui Province(No. 2108085J18)the National Natural Science Foundation of China (Nos. 32011540382 and 32102272)。
文摘Chemical investigations of the termite-associated Streptomyces tanashiensis BYF-112 resulted in the discovery of four novel alkaloid derivatives: vegfrecines A and B(1 and 2), exfoliazone A(3), and venezueline H(7), in addition to nine known metabolites(4-6, 8-13). The structures of these compounds were elucidated through comprehensive spectroscopic analysis and comparison with existing literature data. Antibacterial assays revealed that viridomycin A(11) exhibited potent antibacterial activity against Staphylococcus aureus, with a zone of inhibition(ZOI) of 12.67 mm, in comparison to a ZOI of 17.67 mm for the positive control gentamicin sulfate. Viridomycin A(11) showed moderate activity against Micrococcus tetragenus and Pseudomonas syringae pv. actinidae, with ZOI values of 15.50 and 14.33 mm, respectively, which were inferior to those of gentamicin sulfate(34.67 and 24.00mm). Viridomycin F(12) also exhibited moderate antibacterial effects against S. aureus, M. tetragenus, and P. syringae pv. actinidae,with ZOI values of 8.33, 16.50, and 10.83 mm, respectively. Cytotoxicity assays demonstrated that viridobruunine A(5), exfoliazone(6), viridomycin A(11), and X-14881E(13) exhibited significant cytotoxicity against human malignant melanoma(A375), ovarian cancer(SKOV-3), and gastric cancer(MGC-803) cell lines, with IC_(50) values ranging from 4.61 to 19.28 μmol·L^(-1). Furthermore, bioinformatic analysis of the complete genome of S. tanashiensis suggested a putative biosynthetic gene cluster(BGC) responsible for the production of compounds 1-12. These findings indicate that the secondary metabolites of insect-associated S. tanashiensis BYF-112hold promise as potential sources of novel antibacterial and anticancer agents.