Progress 10/01/09 to 01/12/12
Outputs
Progress Report Objectives (from AD-416): Compare and contrast biotic and abiotic factors that contribute to establishment and spread of Formosan subterranean termite (FST) populations in urban and rural forested areas. Determine intrinsic and extrinsic factors that regulate termite growth, metabolism, caste development, social behavior, and foraging. Identify and characterize genes involved in critical biological functions (e.g., apoptosis, metabolism, chemoreception, pheromone regulation, sexual reproduction, and sex determination) with the goal of developing gene- targeted technologies for species-specific, biologically-based control of termites. Develop more precise and accurate methods and survey protocols for assessing Formosan subterranean termite populations. Approach (from AD-416): The Formosan subterranean termite (FST), Coptotermes formosanus Shiraki, is native to Asia but it was introduced into the southern United States where it has become a devastating pest and in some states has been described as the most costly insect pest. The total annual economic loss due to all species of subterranean termites in the United States has been estimated to cost as much as $11 billion per year including preventive and remedial treatments and damage repair costs. Costs associated with the FST are estimated at $1-2 billion per year. In addition to structural infestations, C. formosanus infestations of living trees are common, causing unquantifiable aesthetic damage and serving as untreated refugia and a source for further structural attack. The known range of this important invasive species continues to expand indicating the need to minimize establishment of this species in new areas. Termites are also long-lived and cryptic insects that require novel treatments for population management to minimize economic damage. Much of the long distance spread of this termite has been attributed to movement of infested materials through commerce, particularly infested railroad ties that are subsequently used for landscape timbers. We plan to identify factors that are particularly conducive to colony establishment and growth that could provide new strategies to minimize the establishment of infestations in new areas. We will investigate landscape features that promote growth and colony development could provide establishment of guidelines to minimize termite colonization in areas into which they are inadvertently introduced. Research focused on identification of intrinsic and extrinsic factors that regulate termite growth, metabolism, caste development, social behavior, and foraging will provide critical information that could lead to development of novel termite control products. Research on caste development will be conducted to provide new target sites for chemical control. Determining factors involved in termite foraging behavior will enable us to improve monitoring programs and increase the efficacy of termite baits. Characterize genes associated with caste differentiation and development and regulation of physiological pathways (digestion, molting, immunity, symbiotic relationships, etc.) that is expected to provide novel target site(s) that would be developed into new strategies for the effective area-wide integrated management of FST. Plans are to develop more precise and accurate methods and survey protocols for assessing FST populations for improving our ability to accurately evaluate the effectiveness of termite control products, to increase our ability to detect the presence of FST, and to study the spread of this invasive pest species. Studies on the effects of temperature, humidity, and moisture on the survival of subterranean termite workers, soldiers, and alates were completed. Survival of alates at low humidity under various temperatures allowed geographic information systems (GIS) models of potential Formosan Subterranean termite (FST) distribution to be improved, particularly for the Southwestern United States. Previous models incorporated climate variables that provided a good fit for known distributions in the Southeast, but could not be assessed where there are no established populations. Soil physical and chemical properties can affect termite colony establishment and survival directly and indirectly by influencing moisture availability, compaction, termiticide performance, and the survival of other organisms. ARS scientists continued to assess correlations between soil properties and termite presence in field surveys. Effects of soil properties on persistence of termiticides in weathered soils were assessed, as determined by activity against FST and nontarget invertebrates. November 2011 Congress terminated the Formosan subterranean termite program. Accomplishments 01 ARS scientists initiated a joint project focused at sequencing termite genome. ARS scientists at Southern Regional Research Center (SRRC) in N Orleans, LA, initiated a joint project focused at sequencing the Coptotermes formosanus genome and its comparison to the Reticulitermes flavipes genome. This work is in collaboration with researchers at the J Craig Venter Institute (JCVI) and Purdue University. Currently we have completed 18x coverage of the 926 mb genome using Illumina Nextgen sequencing. The goals to have 80x coverage of the genome by fall 2011 a assembly and annotation completed by spring 2012 were thwarted with fisc year budget cuts. 02 Identified and characterized a novel endogenous endo-�-1,4-glucanase (named CfEG5) in the Formosan Subterranean termite (FST). Gene structur expression, function and phylogenetic relatedness of CfEG5 and the enzym specificity and kinetics of the recombinant CfEG5 were analyzed comparatively with the early-studied CfEG3a. 03 ARS scientists identify genes. ARS scientists at Southern Regional Research Center (SRRC) in New Orleans, LA, identified 11 out of 15 genes belonging to the metabolic mevalonate pathway. This pathway is responsib for the production of the morphogenic hormone, juvenile hormone. 04 ARS scientist develop phenotypic bioassays that promote and inhibit pathway. ARS scientists at Southern Regional Research Center (SRRC) in New Orleans, LA, gathered phenotypic data and gene expression profiles f the mevalonate pathway genes then developed phenotypic bioassays with chemicals that promote and inhibit the mevalonate pathway. Chemicals tha up-regulate the pathway increase worker to soldier differentiation, whil chemicals that inhibit the pathway decrease the worker to soldier differentiation. 05 ARS scientists discover Myosin heavy-chain in Coptotermes. Formosanus termites as a focus: ARS scientists at Southern Regional Research Center (SRRC) in New Orleans, LA, discovered a partial ene/protein sequence, ge and protein expression profiles between worker and soldier termites, and expression profiles between worker and soldier termite body regions. 06 Carbohydrate degrading enzyme inhibitor was identified and characterized as potent, stable, non-toxic, and bio-degradable. Bioassays showed that there is no feeding repellency or rejection with choice tests at lethal concentrations (0.25 mM � 1.0 mM or 0.008% to 0.03% of active ingredient in water, wt/wt). Lethal effects occurred 5 to 6 days after voluntary feeding of the inhibitor-treated cellulosic materials, resulting in 91% 100% mortality after another 5 to 8 days. 07 Completed laboratory studies on the effects of temperature, humidity, an moisture on the survival of subterranean termite workers, soldiers, and alates. Survival of alates at low humidity under various temperatures allowed geographic information system (GIS) models of potential Formosan Subterranean termite (FST) distribution to be improved, particularly for the Southwestern United States. Previous models incorporated climate variables that provided a good fit for known distributions in the southeast, but could not be assessed where there are no established populations. 08 ARS scientists uncover correlation between soil properties and termites. Soil physical and chemical properties can affect termite colony establishment and survival directly and indirectly by influencing moistu availability, compaction, termiticide performance, and the survival of other organisms. Correlations between soil properties and termite presen in field surveys will continued to be studied by ARS scientists at Southern Regional Research Center (SRRC) in New Orleans, LA. Effects of soil properties on persistence of termiticides in weathered soils were assessed, as determined by activity against the Formosan subterranean termite (FST) and nontarget invertebrates.
Impacts
(N/A)
Publications
- Zhang, D., Allen, A.B., Lax, A.R. 2012. Functional analyses of the digestive �-Glucosidase of Formosan Subterranean Termites (Coptotermes formosanus). Journal of Insect Physiology. 58(1):205-210.
- Zhang, D., Lax, A.R., Hennrisat, H., Coutinho, P., Katiya, N., Nierman, W. C., Fedorova, N. 2012. Carbohydrate active enzymes revealed in Coptotermes formosanus transcriptome. Insect Molecular Biology. 21(2):235-245.
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Progress 10/01/10 to 09/30/11
Outputs
Progress Report Objectives (from AD-416) Compare and contrast biotic and abiotic factors that contribute to establishment and spread of Formosan subterranean termite (FST) populations in urban and rural forested areas. Determine intrinsic and extrinsic factors that regulate termite growth, metabolism, caste development, social behavior, and foraging. Identify and characterize genes involved in critical biological functions (e.g., apoptosis, metabolism, chemoreception, pheromone regulation, sexual reproduction, and sex determination) with the goal of developing gene- targeted technologies for species-specific, biologically-based control of termites. Develop more precise and accurate methods and survey protocols for assessing Formosan subterranean termite populations. Approach (from AD-416) The Formosan subterranean termite (FST), Coptotermes formosanus Shiraki, is native to Asia but it was introduced into the southern United States where it has become a devastating pest and in some states has been described as the most costly insect pest. The total annual economic loss due to all species of subterranean termites in the United States has been estimated to cost as much as $11 billion per year including preventive and remedial treatments and damage repair costs. Costs associated with the FST are estimated at $1-2 billion per year. In addition to structural infestations, C. formosanus infestations of living trees are common, causing unquantifiable aesthetic damage and serving as untreated refugia and a source for further structural attack. The known range of this important invasive species continues to expand indicating the need to minimize establishment of this species in new areas. Termites are also long-lived and cryptic insects that require novel treatments for population management to minimize economic damage. Much of the long distance spread of this termite has been attributed to movement of infested materials through commerce, particularly infested railroad ties that are subsequently used for landscape timbers. We plan to identify factors that are particularly conducive to colony establishment and growth that could provide new strategies to minimize the establishment of infestations in new areas. We will investigate landscape features that promote growth and colony development could provide establishment of guidelines to minimize termite colonization in areas into which they are inadvertently introduced. Research focused on identification of intrinsic and extrinsic factors that regulate termite growth, metabolism, caste development, social behavior, and foraging will provide critical information that could lead to development of novel termite control products. Research on caste development will be conducted to provide new target sites for chemical control. Determining factors involved in termite foraging behavior will enable us to improve monitoring programs and increase the efficacy of termite baits. We will characterize genes associated with caste differentiation and development and regulation of physiological pathways (digestion, molting, immunity, symbiotic relationships, etc.) that is expected to provide novel target site(s) that would be developed into new strategies for the effective area-wide integrated management of FST. We plan to develop more precise and accurate methods and survey protocols for assessing FST populations for improving our ability to accurately evaluate the effectiveness of termite control products, to increase our ability to detect the presence of FST, and to study the spread of this invasive pest species. Researchers in the Formosan Subterranean Termite Research Unit in New Orleans, LA, continue to sequence and annotate genes expressed by the Formosan Subterranean Termite (FST) and have begun complete genome sequencing of the FST. Using new technology, we were able to determine genes differentially expressed among various castes (workers, soldiers and reproductives) of the FST. We discovered and identified a group of enzymes from an expressed sequence tag (EST) library containing many of the representative genes in FST and expressed genes encoding those enzymes in the bacterium, E. coli. The proteins have been purified and were demonstrated to digest various sugar polymers including a trehalase enzyme. A novel female specific glucosidase has been discovered and seems to influence reproductive recognition. Various inhibitors that could be useful in termite control are being tested against several glycohydrolase enzyme. We have also identified a specific chemical isolated from the female reproductive caste of the Formosan subterranean termite. This chemical is a natural substrate of a termite specific glucosidase enzymes and seems to play a role in mate recognition. Further characterization of its biological activity is underway. We have demonstrated a strict temperature dependence of the action of a synthetic insect juvenile hormone to cause caste differentiation from workers to soldiers. Using this combination to induce soldier formation will allow us to determine genes that are activated or down regulated that might control the differentiation process. Furthermore, the synthetic hormone causes changes in the levels of several forms of an enzyme responsible for the degradation of the native hormone. This change in levels of degrading enzyme may also play a significant role in the differentiation process. Genetic analysis of all castes of termites using techniques to show what genes are expressed continues to reveal genes involved with caste differentiation and colony development. This information should provide the basis for new targets for termite control. Improved methods for detecting juvenile hormone from termites are being developed. We have demonstrated that juvenile hormone affects levels of a muscle specific protein and carbohydrate degrading enzymes along with specific differentiation into pre-soldier castes. We have begun to investigate compounds from known termite attracting substrates to improve termite attraction to termite bait stations. We have updated a model for the distribution of FST using ARCGIS software based on climatological data habitat and other landscape features encompassing that might provide improved prediction for occurrence and future spread of FST. Diligent monitoring of termite habitat, presence, gathering samples and compiling that information into useable data is crucial and has always been key component in the management of this species. We employ a variety of methods achieve this goal from conducting laboratory and field surveys to determine effects of moisture on termite foraging and feeding and to help determine termite response to periodic flooding to genome sequencing. Accomplishments 01 Identified and characterized a novel endogenous endo-�-1,4-glucanase (named CfEG5) in the Formosan Subterranean Termite (FST). The gene structure, expression, function and phylogenetic relatedness of CfEG5 an the enzyme specificity and kinetics of the recombinant CfEG5 were analyz comparatively with the early-studied CfEG3a. 02 Unit has initiated a joint project focused at sequencing the Coptotermes formosanus genome and its comparison to the Reticulitermes flavipes geno This work is in collaboration with researchers at J. Craig Venter Institute, Inc. and Purdue University. Currently, the Formosan Subterranean Termite Research Unit in New Orleans, LA, has completed 18x coverage of the 926 mb genome using Illumina Nextgen sequencing. We expe 80x coverage of the genome by fall 2011 and assembly and annotation to b completed by spring 2012. 03 Formosan Subterranean Termite Research Unit in New Orleans, LA, has identified 11 out of 15 genes belonging to the metabolic mevalonate pathway. This pathway is responsible for the production of the morphogenic hormone, juvenile hormone. 04 Formosan Subterranean Termite Research Unit in New Orleans, LA, has developed phenotypic bioassays with chemicals that promote and inhibit t mevalonate pathway. Chemicals that up-regulate the pathway increase worker to soldier differentiation, while chemicals that inhibit the pathway decrease the worker to soldier differentiation. We have gathered phenotypic data and gene expression profiles for the mevalonate pathway genes. 05 Focus on myosin heavy-chain in Coptotermes formosanus termites. Formosa Subterranean Termite Research Unit in New Orleans, LA, has a partial gene/protein sequence, gene and protein expression profiles between work and soldier termites, and expression profiles between worker and soldier termite body regions. 06 Formosan Subterranean Termite Research Unit in New Orleans, LA, has identified and characterized a carbohydrate degrading enzyme inhibitor, which is potent, stable, non-toxic, and bio-degradable. Bioassays showe that there is no feeding repellency or rejection with choice tests at lethal concentrations (0.25 mM � 1.0 mM or 0.008% to 0.03% of active ingredient in water, wt/wt). Lethal effects occurred 5 to 6 days after voluntary feeding of the inhibitor-treated cellulosic materials, resulti in 91% to 100% mortality after another 5 to 8 days.
Impacts
(N/A)
Publications
- Zhang, D., Lax, A.R., Bland, J.M. 2011. Characterization of a new endogenous endo-�-1,4-glucanase of Formosan subterranean termite (Coptotermes formosanus). Journal of Insect Biochemistry and Molecular Biology. 41:211-218.
- Wiltz, B.A. 2010. Laboratory evaluation of effects of soil properties on termiticide performance against Formosan Subterranean Termites (Isoptera: Rhinotermitidae) Sociobiology 56(3):755-773.
- Tarver, M.R., Schmelz, E.A., Scharf, M.E. 2011. Soldier caste influences on candidate primer pheromone levels and juvenile hormone-dependent caste differentiation in workers of the termite Reticulitermes flavipes. Journal of Insect Physiology. 57:771�777.
- Osbrink, W.L., Cornelius, M.L., Lax, A.R. 2011. Area wide field study on effect of three chitin synthesis inhibitor baits on populations of Coptotermes formosanus Shiraki and Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae). Journal of Economic Entomology 104(3):1009- 1017.
- Cornelius, M.L., Osbrink, W.L. 2011. Effect of seasonal changes in soil temperature and moisture on wood consumption and foraging activity of the Formosan Subterranean Termite (Isoptera: Rhinotermitidae). Journal of Economic Entomology 104:1009-1017.
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Progress 10/01/09 to 09/30/10
Outputs
Progress Report Objectives (from AD-416) Compare and contrast biotic and abiotic factors that contribute to establishment and spread of Formosan subterranean termite (FST) populations in urban and rural forested areas. Determine intrinsic and extrinsic factors that regulate termite growth, metabolism, caste development, social behavior, and foraging. Identify and characterize genes involved in critical biological functions (e.g., apoptosis, metabolism, chemoreception, pheromone regulation, sexual reproduction, and sex determination) with the goal of developing gene- targeted technologies for species-specific, biologically-based control of termites. Develop more precise and accurate methods and survey protocols for assessing Formosan subterranean termite populations. Approach (from AD-416) The Formosan subterranean termite (FST), Coptotermes formosanus Shiraki, is native to Asia but it was introduced into the southern United States where it has become a devastating pest and in some states has been described as the most costly insect pest. The total annual economic loss due to all species of subterranean termites in the United States has been estimated to cost as much as $11 billion per year including preventive and remedial treatments and damage repair costs. Costs associated with the FST are estimated at $1-2 billion per year. In addition to structural infestations, C. formosanus infestations of living trees are common, causing unquantifiable aesthetic damage and serving as untreated refugia and a source for further structural attack. The known range of this important invasive species continues to expand indicating the need to minimize establishment of this species in new areas. Termites are also long-lived and cryptic insects that require novel treatments for population management to minimize economic damage. Much of the long distance spread of this termite has been attributed to movement of infested materials through commerce, particularly infested railroad ties that are subsequently used for landscape timbers. We plan to identify factors that are particularly conducive to colony establishment and growth that could provide new strategies to minimize the establishment of infestations in new areas. We will investigate landscape features that promote growth and colony development could provide establishment of guidelines to minimize termite colonization in areas into which they are inadvertently introduced. Research focused on identification of intrinsic and extrinsic factors that regulate termite growth, metabolism, caste development, social behavior, and foraging will provide critical information that could lead to development of novel termite control products. Research on caste development will be conducted to provide new target sites for chemical control. Determining factors involved in termite foraging behavior will enable us to improve monitoring programs and increase the efficacy of termite baits. We will characterize genes associated with caste differentiation and development and regulation of physiological pathways (digestion, molting, immunity, symbiotic relationships, etc.) that is expected to provide novel target site(s) that would be developed into new strategies for the effective area-wide integrated management of FST. We plan to develop more precise and accurate methods and survey protocols for assessing FST populations for improving our ability to accurately evaluate the effectiveness of termite control products, to increase our ability to detect the presence of FST, and to study the spread of this invasive pest species. We have completed the first stages of sampling termite presence and habitat and have created a model for the distribution of the Formosan Subterranean Termite (FST) using ARCGIS based on climatological data encompassing areas known to have the termite. We are expanding the database to include habitat and other landscape features that might provide improved prediction for the occurrence and future spread of the termite. We conducted both laboratory and field surveys in order to determine whether seasonal changes cause significant effects on the foraging activity and wood consumption of FST in New Orleans and how changes in specific climatic variables affect termite foraging behavior. Wood consumption, number of stations occupied by FST, soil temperatures, and soil moisture were measured at 20 test stations monthly over a two-year period. In addition, foraging activity of FST at every monitoring station was recorded monthly. Foraging activity of termites was also compared with average monthly air temperature and total monthly precipitation. In addition, differences in wood consumption and length of time individual test stations were occupied were compared over the two-year period. We continue to sequence and annotate genes expressed by the FST. Further, we have begun using gene sequencing technology to determine genes differentially expressed among various castes (workers, soldiers, and reproductives) of the FST. We have identified a group of enzymes from an expressed sequence tag (EST) library containing many of the representative genes in FST and have expressed the genes encoding those enzymes in the bacterium, E. coli. The proteins have been purified and were demonstrated to digest various sugar polymers. A combination of one endoglucanase and a glycosidase are capable of digesting cellulose completely to glucose. We are using the enzymes in vitro to test various inhibitors that could be useful in termite control. A specific chemical has been isolated from the female reproductive caste of the Formosan subterranean termite and has been identified. This chemical is a natural substrate of one of the termite specific glucosidase enzymes and may play some role in mate recognition. Further characterization of its biological activity is underway. We have demonstrated a strict temperature dependence of the action of a synthetic insect juvenile hormone to cause caste differentiation from workers to soldiers. Using this combination to induce soldier formation will allow us to determine genes that are activated or down regulated that might control the differentiation process. We have further demonstrated that the synthetic hormone causes changes in the levels over time of several forms of an enzyme responsible for the degradation of the native hormone. This change in levels of the degrading enzyme may also play a significant role in the differentiation process. Genetic analysis of all castes of termites using techniques to show what genes are expressed is continuing to reveal those that are involved with caste differentiation and colony development that should provide the basis for new targets for termite control. Accomplishments 01 Cloning and Expression of Glycohydrolases Capable of Converting Cellulos to Glucose as New Termite Control Target Sites. There are few molecular target sites for the development of new termite control chemicals. ARS scientists in New Orleans, LA, have cloned two enzymes from the Formosan subterranean termite and expressed them in a bacterial expression system Incubation of the two enzymes together with cellulose results in digesti of the cellulose to glucose. This will allow us to test a variety of possible inhibitory compounds against the digestive enzymes necessary fo the termites as a possible wood preservative or termite control agent. A additional outcome for this research is the possible use of these enzyme for the conversion of biomass into biofuel.
Impacts
(N/A)
Publications
- Lax, A.R., Wiltz, B.A. Swarming of the Formosan Subteranean Termite (Isoptera: Rhinotermitidae) in Southern Mississippi. Midsouth Entomologist. 3(1):18�25. 2010.
- Zhang, D., Lax, A.R., Yu, J., Nierman, W.C., Fedorova, N. 2010. Hydrolysis of Filter-Paper Cellulose to Glucose by Two Recombinant Endogenous Glycosyl Hydrolases of Coptotermes formosanus. Insect Science. 17(3) :245�252.
- Tarver, M.R., Zhou, X., Scharf, M. 2010. Socio-environmental influences on 1 developmental and caste-regulatory gene expression in the eusocial insect Reticulitermes flavipes. BioMed Central (BMC) Molecular Biology. (11)28:1471-2199.
- Guillot, F.S., Lax, A.R., Ring, D.R., Morgan, A., Brown, K., Riegel, C., Boykin, D.L. 2010. Area-Wide Management of the Formosan subterranean termite, Coptotermes formosanus, Shiraki (Isoptera: Rhinotermitidae) in the New Orleans French Quarter. Sociobiology 55(2): 311-338.
- Cornelius, M.L., Osbrink, W.L. 2010. Effect of Soil Type and Moisture Availability on the Foraging Behavior of the Formosan Subterranean Termite (Isoptera: Rhinotermitidae). Journal of Economic Entomology. 103(3):799- 807.
- Tarver, M.R., Schmelz, E.A., Rocca, J.R., Scharf, M.E. 2009. Effects of soldier-derived terpenes on soldier caste differentiation in the termite Reticulitermes flavipes. Journal of Chemical Ecology. 35: 256-264.
- Wiltz, B.A., Woodson, W.D., Puterka, G.J. 2010. Potential of Kaolin-based Particle Film Barriers for Formosan Subterranean Termite (Isoptera: Rhinotermitidae) Control. Sociobiology. 55(2):405-413.
- Wiltz, B.A., Suiter, D.R., Gardner, W.A., Berisford, C.W. A Novel delivery Method for Ant (Hymenoptera: Formicidae) toxicants. Midsouth Entomologist. 3(2)79-88. 2010.
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