Binding and entry of a non-enveloped T=4 insect RNA virus is triggered by alkaline pH
- Penkler, David L, Jiwaji, Meesbah, Domitrovic, Tatiana, Short, James R, Johnson, John E, Dorrington, Rosemary A
- Authors: Penkler, David L , Jiwaji, Meesbah , Domitrovic, Tatiana , Short, James R , Johnson, John E , Dorrington, Rosemary A
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/65995 , vital:28875 , https://doi.org/10.1016/j.virol.2016.08.028
- Description: publisher version , Tetraviruses are small, non-enveloped, RNA viruses that exclusively infect lepidopteran insects. Their particles comprise 240 copies of a single capsid protein precursor (CP), which undergoes autoproteolytic cleavage during maturation. The molecular mechanisms of capsid assembly and maturation are well understood, but little is known about the viral infectious lifecycle due to a lack of tissue culture cell lines that are susceptible to tetravirus infection. We show here that binding and entry of the alphatetravirus, Helicoverpa armigera stunt virus (HaSV), is triggered by alkaline pH. At pH 9.0, wild-type HaSV virus particles undergo conformational changes that induce membrane-lytic activity and binding to Spodoptera frugiperda Sf9 cells. Binding is followed by entry and infection, with virus replication complexes detected by immunofluorescence microscopy within 2 h post-infection and the CP after 12 h. HaSV particles produced in S. frugiperda Sf9 cells are infectious. Helicoverpa armigera larval virus biofeed assays showed that pre-treatment with the V-ATPase inhibitor, Bafilomycin A1, resulted in a 50% decrease in larval mortality and stunting, while incubation of virus particles at pH 9.0 prior to infection restored infectivity. Together, these data show that HaSV, and likely other tetraviruses, requires the alkaline environment of the lepidopteran larval midgut for binding and entry into host cells.
- Full Text: false
- Date Issued: 2016
- Authors: Penkler, David L , Jiwaji, Meesbah , Domitrovic, Tatiana , Short, James R , Johnson, John E , Dorrington, Rosemary A
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/65995 , vital:28875 , https://doi.org/10.1016/j.virol.2016.08.028
- Description: publisher version , Tetraviruses are small, non-enveloped, RNA viruses that exclusively infect lepidopteran insects. Their particles comprise 240 copies of a single capsid protein precursor (CP), which undergoes autoproteolytic cleavage during maturation. The molecular mechanisms of capsid assembly and maturation are well understood, but little is known about the viral infectious lifecycle due to a lack of tissue culture cell lines that are susceptible to tetravirus infection. We show here that binding and entry of the alphatetravirus, Helicoverpa armigera stunt virus (HaSV), is triggered by alkaline pH. At pH 9.0, wild-type HaSV virus particles undergo conformational changes that induce membrane-lytic activity and binding to Spodoptera frugiperda Sf9 cells. Binding is followed by entry and infection, with virus replication complexes detected by immunofluorescence microscopy within 2 h post-infection and the CP after 12 h. HaSV particles produced in S. frugiperda Sf9 cells are infectious. Helicoverpa armigera larval virus biofeed assays showed that pre-treatment with the V-ATPase inhibitor, Bafilomycin A1, resulted in a 50% decrease in larval mortality and stunting, while incubation of virus particles at pH 9.0 prior to infection restored infectivity. Together, these data show that HaSV, and likely other tetraviruses, requires the alkaline environment of the lepidopteran larval midgut for binding and entry into host cells.
- Full Text: false
- Date Issued: 2016
Exploring the potential impacts of tourism development on social and ecological change in the Solomon Islands
- Diedrich, Amy, Aswani, Shankar
- Authors: Diedrich, Amy , Aswani, Shankar
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67335 , vital:29074 , https://doi.org/10.1007/s13280-016-0781-x
- Description: publisher version , Pacific Island communities may be vulnerable to negative impacts of economic development, which is often considered a strategy for reducing vulnerability to environmental change. Studies that evaluate potential impacts of economic development in isolated communities may be inaccurate to only focus on asking people to anticipate impacts of phenomena they have had minimal exposure to. We used an open-ended approach to evaluate how communities in the Solomon Islands perceived change, and used this information to anticipate potential impacts of the government’s plans to develop tourism. Our results showed mostly negative expectations of change, particularly socio-cultural, which was perceived as being driven by diminishing social capital, foreign influence, and economic development. Despite minimal exposure, locals supported tourism and had more positive expectations of change associated with this activity. Our findings emphasize the need for locally appropriate planning to ensure intended positive impacts of tourism and other forms of economic development.
- Full Text: false
- Date Issued: 2016
- Authors: Diedrich, Amy , Aswani, Shankar
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67335 , vital:29074 , https://doi.org/10.1007/s13280-016-0781-x
- Description: publisher version , Pacific Island communities may be vulnerable to negative impacts of economic development, which is often considered a strategy for reducing vulnerability to environmental change. Studies that evaluate potential impacts of economic development in isolated communities may be inaccurate to only focus on asking people to anticipate impacts of phenomena they have had minimal exposure to. We used an open-ended approach to evaluate how communities in the Solomon Islands perceived change, and used this information to anticipate potential impacts of the government’s plans to develop tourism. Our results showed mostly negative expectations of change, particularly socio-cultural, which was perceived as being driven by diminishing social capital, foreign influence, and economic development. Despite minimal exposure, locals supported tourism and had more positive expectations of change associated with this activity. Our findings emphasize the need for locally appropriate planning to ensure intended positive impacts of tourism and other forms of economic development.
- Full Text: false
- Date Issued: 2016
Water footprint assessment of citrus production in South Africa: A case study of the Lower Sundays River Valley
- Munro, Samantha A, Fraser, Gavin C G, Snowball, Jeanette D, Pahlow, Markus
- Authors: Munro, Samantha A , Fraser, Gavin C G , Snowball, Jeanette D , Pahlow, Markus
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69240 , vital:29463 , https://doi.org/10.1016/j.jclepro.2016.06.142
- Description: Water footprint assessment is a developing method that is being increasingly applied to quantify water use, prioritise reductions, assess sustainability and provide information to achieve sustainable, efficient, and equitable water use. The objectives of this paper were to conduct a water footprint assessment of primary citrus production within the Lower Sundays River Valley in South Africa using local, high-resolution data and to examine indicators (water scarcity, pollution, efficiency, productivity and access) to determine the sustainability of blue, green and grey water footprints of a wet, dry and average year. Lemons were found to have the lowest blue and combined green-blue water footprint per ton of production across all climatic years, followed by soft citrus, valencias and navels. Valencias had the lowest, and navels the highest grey WF (relating to inorganic nitrogen). Lemons, despite their high crop water and fertiliser requirements, were regarded more economically efficient in comparison to valencias, soft citrus and navels, in that they provided higher net income and more employment hours per m3 of water in comparison to other citrus crops. In an average season, lemons generated approximately 39% more income per m3 of water than navels, despite navels being the dominant cultivar. Blue water consumption for citrus in the catchment was calculated to be 58.7 Mm3 for an average season and 89.2 Mm3 for a dry season. Due to an inter-basin transfer scheme, no physical water scarcity occurred, and both environmental and basic human needs are met. Water pollution levels related to nitrogen however, exceeded the assimilative capacity of the run-off in dry years. The area also experiences institutional and infrastructural scarcity and 14% of the population do not have access to piped water. Stakeholders and governments may use the results of water footprint assessments to determine the status of river basins, make evaluations for future water usage and the potential impacts of expanding agriculture and different management strategies. Including environmental and socio-economic indicators will also improve the integrity of water footprint assessments.
- Full Text: false
- Date Issued: 2016
- Authors: Munro, Samantha A , Fraser, Gavin C G , Snowball, Jeanette D , Pahlow, Markus
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69240 , vital:29463 , https://doi.org/10.1016/j.jclepro.2016.06.142
- Description: Water footprint assessment is a developing method that is being increasingly applied to quantify water use, prioritise reductions, assess sustainability and provide information to achieve sustainable, efficient, and equitable water use. The objectives of this paper were to conduct a water footprint assessment of primary citrus production within the Lower Sundays River Valley in South Africa using local, high-resolution data and to examine indicators (water scarcity, pollution, efficiency, productivity and access) to determine the sustainability of blue, green and grey water footprints of a wet, dry and average year. Lemons were found to have the lowest blue and combined green-blue water footprint per ton of production across all climatic years, followed by soft citrus, valencias and navels. Valencias had the lowest, and navels the highest grey WF (relating to inorganic nitrogen). Lemons, despite their high crop water and fertiliser requirements, were regarded more economically efficient in comparison to valencias, soft citrus and navels, in that they provided higher net income and more employment hours per m3 of water in comparison to other citrus crops. In an average season, lemons generated approximately 39% more income per m3 of water than navels, despite navels being the dominant cultivar. Blue water consumption for citrus in the catchment was calculated to be 58.7 Mm3 for an average season and 89.2 Mm3 for a dry season. Due to an inter-basin transfer scheme, no physical water scarcity occurred, and both environmental and basic human needs are met. Water pollution levels related to nitrogen however, exceeded the assimilative capacity of the run-off in dry years. The area also experiences institutional and infrastructural scarcity and 14% of the population do not have access to piped water. Stakeholders and governments may use the results of water footprint assessments to determine the status of river basins, make evaluations for future water usage and the potential impacts of expanding agriculture and different management strategies. Including environmental and socio-economic indicators will also improve the integrity of water footprint assessments.
- Full Text: false
- Date Issued: 2016
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