Antiviral drug discovery: preparing for the next pandemic
- Adamson, Catherine S, Chibale, Kelly, Goss, Rebecca J M, Jaspars, Marcel, Newman, David J, Dorrington, Rosemary A
- Authors: Adamson, Catherine S , Chibale, Kelly , Goss, Rebecca J M , Jaspars, Marcel , Newman, David J , Dorrington, Rosemary A
- Date: 2021
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/177499 , vital:42827 , DOI: 10.1039/d0cs01118e
- Description: Clinically approved antiviral drugs are currently available for only 10 of the more than 220 viruses known to infect humans. The SARS-CoV-2 outbreak has exposed the critical need for compounds that can be rapidly mobilised for the treatment of re-emerging or emerging viral diseases, while vaccine development is underway. We review the current status of antiviral therapies focusing on RNA viruses, highlighting strategies for antiviral drug discovery and discuss the challenges, solutions and options to accelerate drug discovery efforts.
- Full Text:
- Date Issued: 2021
- Authors: Adamson, Catherine S , Chibale, Kelly , Goss, Rebecca J M , Jaspars, Marcel , Newman, David J , Dorrington, Rosemary A
- Date: 2021
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/177499 , vital:42827 , DOI: 10.1039/d0cs01118e
- Description: Clinically approved antiviral drugs are currently available for only 10 of the more than 220 viruses known to infect humans. The SARS-CoV-2 outbreak has exposed the critical need for compounds that can be rapidly mobilised for the treatment of re-emerging or emerging viral diseases, while vaccine development is underway. We review the current status of antiviral therapies focusing on RNA viruses, highlighting strategies for antiviral drug discovery and discuss the challenges, solutions and options to accelerate drug discovery efforts.
- Full Text:
- Date Issued: 2021
Latrunculid sponges, their microbial communities and secondary metabolites: connecting conserved bacterial symbionts to pyrroloiminoquinone production
- Dorrington, Rosemary A, Hilliar, Storm Hannah, Kalinski, Jarmo-Charles J, Krause, Rui W M, McPhail, Kerry L, Parker-Nance, Shirley, Wlalmsley, Tara A, Waterworth, Samantha C
- Authors: Dorrington, Rosemary A , Hilliar, Storm Hannah , Kalinski, Jarmo-Charles J , Krause, Rui W M , McPhail, Kerry L , Parker-Nance, Shirley , Wlalmsley, Tara A , Waterworth, Samantha C
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/65915 , vital:28858 , https://doi.org/10.1055/s-0036-1596655
- Description: publisher version , The Latrunculiidae are cold water sponges known for their production of bioactive pyrroloiminoquinone alkaloids (e.g. makaluvamines, discorhabdins and tsitsikammamines). Since pyrroloiminoquinones have also been isolated from sponges belonging to other families, ascidians and microorganisms, the biosynthetic origin of these alkaloids in latrunculid sponges is likely microbial. This study focuses on the secondary metabolites produced by closely-related Tsitsikamma species and Cyclacanthia bellae, all latrunculid sponges endemic to Algoa Bay on the South African southeast coast. The sponges produced suites of related pyrroloiminoquinones, including tsitsikammine A and B, and discohabdin C and V, the combination and relative abundance of which is species-specific. Characterisation of the diversity of sponge-associated bacterial communities revealed the unprecedented conservation of two dominant bacterial species. The first, a Betaproteobacterium, is also found in other latrunculids and related sponge families, representing a novel clade of sponge endosymbionts that have co-evolved with their hosts. The second conserved bacterial symbiont is a spirochaete found only in Cyclacanthia and Tsitsikamma species that is likely to have been recruited from free-living spirochaetes in the environment. This study sheds new light on the interactions between latrunculid sponges, their dominant bacterial symbionts, and the potential involvement of these bacteria in pyrroloiminoquinone biosynthesis.
- Full Text: false
- Date Issued: 2016
- Authors: Dorrington, Rosemary A , Hilliar, Storm Hannah , Kalinski, Jarmo-Charles J , Krause, Rui W M , McPhail, Kerry L , Parker-Nance, Shirley , Wlalmsley, Tara A , Waterworth, Samantha C
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/65915 , vital:28858 , https://doi.org/10.1055/s-0036-1596655
- Description: publisher version , The Latrunculiidae are cold water sponges known for their production of bioactive pyrroloiminoquinone alkaloids (e.g. makaluvamines, discorhabdins and tsitsikammamines). Since pyrroloiminoquinones have also been isolated from sponges belonging to other families, ascidians and microorganisms, the biosynthetic origin of these alkaloids in latrunculid sponges is likely microbial. This study focuses on the secondary metabolites produced by closely-related Tsitsikamma species and Cyclacanthia bellae, all latrunculid sponges endemic to Algoa Bay on the South African southeast coast. The sponges produced suites of related pyrroloiminoquinones, including tsitsikammine A and B, and discohabdin C and V, the combination and relative abundance of which is species-specific. Characterisation of the diversity of sponge-associated bacterial communities revealed the unprecedented conservation of two dominant bacterial species. The first, a Betaproteobacterium, is also found in other latrunculids and related sponge families, representing a novel clade of sponge endosymbionts that have co-evolved with their hosts. The second conserved bacterial symbiont is a spirochaete found only in Cyclacanthia and Tsitsikamma species that is likely to have been recruited from free-living spirochaetes in the environment. This study sheds new light on the interactions between latrunculid sponges, their dominant bacterial symbionts, and the potential involvement of these bacteria in pyrroloiminoquinone biosynthesis.
- Full Text: false
- Date Issued: 2016
Molecular Networking Reveals Two Distinct Chemotypes in Pyrroloiminoquinone-Producing Tsitsikamma favus Sponges
- Kalinski, Jarmo-Charles J, Waterworth, Samantha C, Noundou, Xavier S, Jiwaji, Meesbah, Parker-Nance, Shirley, Krause, Rui W M, McPhail, Kerry L, Dorrington, Rosemary A
- Authors: Kalinski, Jarmo-Charles J , Waterworth, Samantha C , Noundou, Xavier S , Jiwaji, Meesbah , Parker-Nance, Shirley , Krause, Rui W M , McPhail, Kerry L , Dorrington, Rosemary A
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/131618 , vital:36673 , https://doi.org/10.3390/md17010060
- Description: The temperate marine sponge, Tsitsikamma favus, produces pyrroloiminoquinone alkaloids with potential as anticancer drug leads. We profiled the secondary metabolite reservoir of T. favus sponges using HR-ESI-LC-MS/MS-based molecular networking analysis followed by preparative purification efforts to map the diversity of new and known pyrroloiminoquinones and related compounds in extracts of seven specimens. Molecular taxonomic identification confirmed all sponges as T. favus and five specimens (chemotype I) were found to produce mainly discorhabdins and tsitsikammamines. Remarkably, however, two specimens (chemotype II) exhibited distinct morphological and chemical characteristics: the absence of discorhabdins, only trace levels of tsitsikammamines and, instead, an abundance of unbranched and halogenated makaluvamines. Targeted chromatographic isolation provided the new makaluvamine Q, the known makaluvamines A and I, tsitsikammamine B, 14-bromo-7,8-dehydro-3-dihydro-discorhabdin C, and the related pyrrolo-ortho-quinones makaluvamine O and makaluvone. Purified compounds displayed different activity profiles in assays for topoisomerase I inhibition, DNA intercalation and antimetabolic activity against human cell lines. This is the first report of makaluvamines from a Tsitsikamma sponge species, and the first description of distinct chemotypes within a species of the Latrunculiidae family. This study sheds new light on the putative pyrroloiminoquinone biosynthetic pathway of latrunculid sponges
- Full Text:
- Date Issued: 2019
- Authors: Kalinski, Jarmo-Charles J , Waterworth, Samantha C , Noundou, Xavier S , Jiwaji, Meesbah , Parker-Nance, Shirley , Krause, Rui W M , McPhail, Kerry L , Dorrington, Rosemary A
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/131618 , vital:36673 , https://doi.org/10.3390/md17010060
- Description: The temperate marine sponge, Tsitsikamma favus, produces pyrroloiminoquinone alkaloids with potential as anticancer drug leads. We profiled the secondary metabolite reservoir of T. favus sponges using HR-ESI-LC-MS/MS-based molecular networking analysis followed by preparative purification efforts to map the diversity of new and known pyrroloiminoquinones and related compounds in extracts of seven specimens. Molecular taxonomic identification confirmed all sponges as T. favus and five specimens (chemotype I) were found to produce mainly discorhabdins and tsitsikammamines. Remarkably, however, two specimens (chemotype II) exhibited distinct morphological and chemical characteristics: the absence of discorhabdins, only trace levels of tsitsikammamines and, instead, an abundance of unbranched and halogenated makaluvamines. Targeted chromatographic isolation provided the new makaluvamine Q, the known makaluvamines A and I, tsitsikammamine B, 14-bromo-7,8-dehydro-3-dihydro-discorhabdin C, and the related pyrrolo-ortho-quinones makaluvamine O and makaluvone. Purified compounds displayed different activity profiles in assays for topoisomerase I inhibition, DNA intercalation and antimetabolic activity against human cell lines. This is the first report of makaluvamines from a Tsitsikamma sponge species, and the first description of distinct chemotypes within a species of the Latrunculiidae family. This study sheds new light on the putative pyrroloiminoquinone biosynthetic pathway of latrunculid sponges
- Full Text:
- Date Issued: 2019
Unlocking the Diversity of Pyrroloiminoquinones Produced by Latrunculid Sponge Species
- Kalinski, Jarmo-Charles J, Krause, Rui W M, Parker-Nance, Shirley, Waterworth, Samantha C, Dorrington, Rosemary A
- Authors: Kalinski, Jarmo-Charles J , Krause, Rui W M , Parker-Nance, Shirley , Waterworth, Samantha C , Dorrington, Rosemary A
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191802 , vital:45165 , xlink:href="https://doi.org/10.3390/md19020068"
- Description: Sponges of the Latrunculiidae family produce bioactive pyrroloiminoquinone alkaloids including makaluvamines, discorhabdins, and tsitsikammamines. The aim of this study was to use LC-ESI-MS/MS-driven molecular networking to characterize the pyrroloiminoquinone secondary metabolites produced by six latrunculid species. These are Tsitsikamma favus, Tsitsikamma pedunculata, Cyclacanthia bellae, and Latrunculia apicalis as well as the recently discovered species, Tsitsikamma nguni and Tsitsikamma michaeli. Organic extracts of 43 sponges were analyzed, revealing distinct species-specific chemical profiles. More than 200 known and unknown putative pyrroloiminoquinones and related compounds were detected, including unprecedented makaluvamine-discorhabdin adducts and hydroxylated discorhabdin I derivatives. The chemical profiles of the new species T. nguni closely resembled those of the known T. favus (chemotype I), but with a higher abundance of tsitsikammamines vs. discorhabdins. T. michaeli sponges displayed two distinct chemical profiles, either producing mostly the same discorhabdins as T. favus (chemotype I) or non- or monobrominated, hydroxylated discorhabdins. C. bellae and L. apicalis produced similar pyrroloiminoquinone chemistry to one another, characterized by sulfur-containing discorhabdins and related adducts and oligomers. This study highlights the variability of pyrroloiminoquinone production by latrunculid species, identifies novel isolation targets, and offers fundamental insights into the collision-induced dissociation of pyrroloiminoquinones.
- Full Text:
- Date Issued: 2021
- Authors: Kalinski, Jarmo-Charles J , Krause, Rui W M , Parker-Nance, Shirley , Waterworth, Samantha C , Dorrington, Rosemary A
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191802 , vital:45165 , xlink:href="https://doi.org/10.3390/md19020068"
- Description: Sponges of the Latrunculiidae family produce bioactive pyrroloiminoquinone alkaloids including makaluvamines, discorhabdins, and tsitsikammamines. The aim of this study was to use LC-ESI-MS/MS-driven molecular networking to characterize the pyrroloiminoquinone secondary metabolites produced by six latrunculid species. These are Tsitsikamma favus, Tsitsikamma pedunculata, Cyclacanthia bellae, and Latrunculia apicalis as well as the recently discovered species, Tsitsikamma nguni and Tsitsikamma michaeli. Organic extracts of 43 sponges were analyzed, revealing distinct species-specific chemical profiles. More than 200 known and unknown putative pyrroloiminoquinones and related compounds were detected, including unprecedented makaluvamine-discorhabdin adducts and hydroxylated discorhabdin I derivatives. The chemical profiles of the new species T. nguni closely resembled those of the known T. favus (chemotype I), but with a higher abundance of tsitsikammamines vs. discorhabdins. T. michaeli sponges displayed two distinct chemical profiles, either producing mostly the same discorhabdins as T. favus (chemotype I) or non- or monobrominated, hydroxylated discorhabdins. C. bellae and L. apicalis produced similar pyrroloiminoquinone chemistry to one another, characterized by sulfur-containing discorhabdins and related adducts and oligomers. This study highlights the variability of pyrroloiminoquinone production by latrunculid species, identifies novel isolation targets, and offers fundamental insights into the collision-induced dissociation of pyrroloiminoquinones.
- Full Text:
- Date Issued: 2021
The African coelacanth genome provides insights into tetrapod evolution:
- Amemiya, Chris T, Alföldi, Jessica, Lee, Alison P, Fan, Shaohua, Philippe, Herve´, MacCallum, Iain, Braasch, Ingo, Manousaki, Tereza, Schneider, Igor, Rohner, Nicolas, Organ, Chris, Chalopin, Domitille, Smith, Jeramiah J, Robinson, Mark, Dorrington, Rosemary A, Gerdol, Marco, Aken, Bronwen, Biscotti, Maria Assunta, Barucca, Marco, Baurain, Denis, Berlin, Aaron, Blatch, Gregory L, Buonocore, Francesco, Burmester, Thorsten, Campbell, Michael S, Canapa, Adriana, Cannon, John P, Christoffels, Alan, De Moro, Gianluca, Edkins, Adrienne L, Fan, Lin, Fausto, Anna Maria, Feiner, Nathalie, Forconi, Mariko, Gamieldien, Junaid, Gnerre, Sante, Gnirke, Andreas, Goldstone, Jared V, Haerty, Wilfried, Hahn, Mark E, Hesse, Uljana, Hoffmann, Steve, Johnson, Jeremy, Karchner, Sibel I, Kuraku, Shigehiro, Lara, Marcia, Levin, Joshua Z, Litman, Gary W, Mauceli, Evan, Miyake, Tsutomu, Mueller, M Gail, Nelson, David R, Nitsche, Anne, Olmo, Ettore, Ota, Tatsuya, Pallavicini, Alberto, Panji, Sumir, Picone, Barbara, Ponting, Chris P, Prohaska, Sonja J, Przybylski, Dariusz, Ratan Saha, Nil, Ravi, Vydianathan, Ribeiro, Filipe J, Sauka-Spengler, Tatjana, Scapigliati, Giuseppe, Searle, Stephen M J, Sharpe, Ted, Simakov, Oleg, Stadler, Peter F, Stegeman, John J, Sumiyama, Kenta, Tabbaa, Diana, Tafer, Hakim, Turner-Maier, Jason, van Heusden, Peter, White, Simon, Williams, Louise, Yandell, Mark, Brinkmann, Henner, Volff, Jean-Nicolas, Tabin, Clifford J, Shubin, Neil, Schartl, Manfred, Jaffe, David B, Postlethwait, John H, Venkatesh, Byrappa, Di Palma, Frederica, Lander, Eric S, Meyer, Axel, Lindblad-Toh, Kerstin
- Authors: Amemiya, Chris T , Alföldi, Jessica , Lee, Alison P , Fan, Shaohua , Philippe, Herve´ , MacCallum, Iain , Braasch, Ingo , Manousaki, Tereza , Schneider, Igor , Rohner, Nicolas , Organ, Chris , Chalopin, Domitille , Smith, Jeramiah J , Robinson, Mark , Dorrington, Rosemary A , Gerdol, Marco , Aken, Bronwen , Biscotti, Maria Assunta , Barucca, Marco , Baurain, Denis , Berlin, Aaron , Blatch, Gregory L , Buonocore, Francesco , Burmester, Thorsten , Campbell, Michael S , Canapa, Adriana , Cannon, John P , Christoffels, Alan , De Moro, Gianluca , Edkins, Adrienne L , Fan, Lin , Fausto, Anna Maria , Feiner, Nathalie , Forconi, Mariko , Gamieldien, Junaid , Gnerre, Sante , Gnirke, Andreas , Goldstone, Jared V , Haerty, Wilfried , Hahn, Mark E , Hesse, Uljana , Hoffmann, Steve , Johnson, Jeremy , Karchner, Sibel I , Kuraku, Shigehiro , Lara, Marcia , Levin, Joshua Z , Litman, Gary W , Mauceli, Evan , Miyake, Tsutomu , Mueller, M Gail , Nelson, David R , Nitsche, Anne , Olmo, Ettore , Ota, Tatsuya , Pallavicini, Alberto , Panji, Sumir , Picone, Barbara , Ponting, Chris P , Prohaska, Sonja J , Przybylski, Dariusz , Ratan Saha, Nil , Ravi, Vydianathan , Ribeiro, Filipe J , Sauka-Spengler, Tatjana , Scapigliati, Giuseppe , Searle, Stephen M J , Sharpe, Ted , Simakov, Oleg , Stadler, Peter F , Stegeman, John J , Sumiyama, Kenta , Tabbaa, Diana , Tafer, Hakim , Turner-Maier, Jason , van Heusden, Peter , White, Simon , Williams, Louise , Yandell, Mark , Brinkmann, Henner , Volff, Jean-Nicolas , Tabin, Clifford J , Shubin, Neil , Schartl, Manfred , Jaffe, David B , Postlethwait, John H , Venkatesh, Byrappa , Di Palma, Frederica , Lander, Eric S , Meyer, Axel , Lindblad-Toh, Kerstin
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165030 , vital:41202 , DOI: 10.1038/nature12027
- Description: The discovery of a living coelacanth specimen in 1938 was remarkable, as this lineage of lobe-finned fish was thought to have become extinct 70 million years ago. The modern coelacanth looks remarkably similar to many of its ancient relatives, and its evolutionary proximity to our own fish ancestors provides a glimpse of the fish that first walked on land. Here we report the genome sequence of the African coelacanth, Latimeria chalumnae. Through a phylogenomic analysis, we conclude that the lungfish, and not the coelacanth, is the closest living relative of tetrapods. Coelacanth protein-coding genes are significantly more slowly evolving than those of tetrapods, unlike other genomic features. Analyses of changes in genes and regulatory elements during the vertebrate adaptation to land highlight genes involved in immunity, nitrogen excretion and the development of fins, tail, ear, eye, brain and olfaction. Functional assays of enhancers involved in the fin-to-limb transition and in the emergence of extra-embryonic tissues show the importance of the coelacanth genome as a blueprint for understanding tetrapod evolution.
- Full Text:
- Date Issued: 2013
- Authors: Amemiya, Chris T , Alföldi, Jessica , Lee, Alison P , Fan, Shaohua , Philippe, Herve´ , MacCallum, Iain , Braasch, Ingo , Manousaki, Tereza , Schneider, Igor , Rohner, Nicolas , Organ, Chris , Chalopin, Domitille , Smith, Jeramiah J , Robinson, Mark , Dorrington, Rosemary A , Gerdol, Marco , Aken, Bronwen , Biscotti, Maria Assunta , Barucca, Marco , Baurain, Denis , Berlin, Aaron , Blatch, Gregory L , Buonocore, Francesco , Burmester, Thorsten , Campbell, Michael S , Canapa, Adriana , Cannon, John P , Christoffels, Alan , De Moro, Gianluca , Edkins, Adrienne L , Fan, Lin , Fausto, Anna Maria , Feiner, Nathalie , Forconi, Mariko , Gamieldien, Junaid , Gnerre, Sante , Gnirke, Andreas , Goldstone, Jared V , Haerty, Wilfried , Hahn, Mark E , Hesse, Uljana , Hoffmann, Steve , Johnson, Jeremy , Karchner, Sibel I , Kuraku, Shigehiro , Lara, Marcia , Levin, Joshua Z , Litman, Gary W , Mauceli, Evan , Miyake, Tsutomu , Mueller, M Gail , Nelson, David R , Nitsche, Anne , Olmo, Ettore , Ota, Tatsuya , Pallavicini, Alberto , Panji, Sumir , Picone, Barbara , Ponting, Chris P , Prohaska, Sonja J , Przybylski, Dariusz , Ratan Saha, Nil , Ravi, Vydianathan , Ribeiro, Filipe J , Sauka-Spengler, Tatjana , Scapigliati, Giuseppe , Searle, Stephen M J , Sharpe, Ted , Simakov, Oleg , Stadler, Peter F , Stegeman, John J , Sumiyama, Kenta , Tabbaa, Diana , Tafer, Hakim , Turner-Maier, Jason , van Heusden, Peter , White, Simon , Williams, Louise , Yandell, Mark , Brinkmann, Henner , Volff, Jean-Nicolas , Tabin, Clifford J , Shubin, Neil , Schartl, Manfred , Jaffe, David B , Postlethwait, John H , Venkatesh, Byrappa , Di Palma, Frederica , Lander, Eric S , Meyer, Axel , Lindblad-Toh, Kerstin
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165030 , vital:41202 , DOI: 10.1038/nature12027
- Description: The discovery of a living coelacanth specimen in 1938 was remarkable, as this lineage of lobe-finned fish was thought to have become extinct 70 million years ago. The modern coelacanth looks remarkably similar to many of its ancient relatives, and its evolutionary proximity to our own fish ancestors provides a glimpse of the fish that first walked on land. Here we report the genome sequence of the African coelacanth, Latimeria chalumnae. Through a phylogenomic analysis, we conclude that the lungfish, and not the coelacanth, is the closest living relative of tetrapods. Coelacanth protein-coding genes are significantly more slowly evolving than those of tetrapods, unlike other genomic features. Analyses of changes in genes and regulatory elements during the vertebrate adaptation to land highlight genes involved in immunity, nitrogen excretion and the development of fins, tail, ear, eye, brain and olfaction. Functional assays of enhancers involved in the fin-to-limb transition and in the emergence of extra-embryonic tissues show the importance of the coelacanth genome as a blueprint for understanding tetrapod evolution.
- Full Text:
- Date Issued: 2013
An update on the indigenous vascular flora of sub-Antarctic Marion Island: taxonomic changes, sequences for DNA barcode loci, and genome size data
- Chau, John H, Mtsi, Nasipi I S, Münbergová, Zuzana, Greve, Michelle, le Roux, Peter C, Mairal, Mario, Le Roux, Johannes J, Dorrington, Rosemary A, van Vuuren, Bettine
- Authors: Chau, John H , Mtsi, Nasipi I S , Münbergová, Zuzana , Greve, Michelle , le Roux, Peter C , Mairal, Mario , Le Roux, Johannes J , Dorrington, Rosemary A , van Vuuren, Bettine
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160344 , vital:40437 , https://0-doi.org.wam.seals.ac.za/10.1007/s00300-020-02747-7
- Description: The flora of sub-Antarctic Marion Island forms part of the unique South Indian Ocean Biogeographic Province, and is under threat from climate change and invasive species. Current information on the flora is necessary to rapidly identify and manage future changes. We conducted a literature search on the taxonomy of indigenous vascular plant species on Marion Island and found nomenclatural changes following taxonomic revisions for Austroblechnum penna-marina (Poir.) Gasper and V.A.O.Dittrich, Carex dikei (Nelmes) K.L.Wilson, Leptinella plumosa Hook.f., Notogrammitis crassior (Kirk) Parris, Phlegmariurus saururus (Lam.) B.Øllg., and Polypogon magellanicus (Lam.) Finot. Additionally, Ranunculus moseleyi Hook.f. was removed from our species checklist due to its long absence in floristic surveys, leaving 21 species in the indigenous vascular plant flora present on Marion Island. We also amplified and sequenced the universal plant barcoding loci rbcL and matK for 19 and 13 species, respectively, and found that ample interspecific genetic distance and minimal intraspecific genetic distance allowed for easy discrimination between species.
- Full Text:
- Date Issued: 2020
- Authors: Chau, John H , Mtsi, Nasipi I S , Münbergová, Zuzana , Greve, Michelle , le Roux, Peter C , Mairal, Mario , Le Roux, Johannes J , Dorrington, Rosemary A , van Vuuren, Bettine
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160344 , vital:40437 , https://0-doi.org.wam.seals.ac.za/10.1007/s00300-020-02747-7
- Description: The flora of sub-Antarctic Marion Island forms part of the unique South Indian Ocean Biogeographic Province, and is under threat from climate change and invasive species. Current information on the flora is necessary to rapidly identify and manage future changes. We conducted a literature search on the taxonomy of indigenous vascular plant species on Marion Island and found nomenclatural changes following taxonomic revisions for Austroblechnum penna-marina (Poir.) Gasper and V.A.O.Dittrich, Carex dikei (Nelmes) K.L.Wilson, Leptinella plumosa Hook.f., Notogrammitis crassior (Kirk) Parris, Phlegmariurus saururus (Lam.) B.Øllg., and Polypogon magellanicus (Lam.) Finot. Additionally, Ranunculus moseleyi Hook.f. was removed from our species checklist due to its long absence in floristic surveys, leaving 21 species in the indigenous vascular plant flora present on Marion Island. We also amplified and sequenced the universal plant barcoding loci rbcL and matK for 19 and 13 species, respectively, and found that ample interspecific genetic distance and minimal intraspecific genetic distance allowed for easy discrimination between species.
- Full Text:
- Date Issued: 2020
Expanding the host range of small insect RNA viruses: Providence virus (Carmotetraviridae) infects and replicates in a human tissue culture cell line
- Jiwaji, Meesbah, Short, James R, Dorrington, Rosemary A
- Authors: Jiwaji, Meesbah , Short, James R , Dorrington, Rosemary A
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/65979 , vital:28874 , https://doi.org/10.1099/jgv.0.000578
- Description: publisher version , Tetraviruses are small, positive (+ve)-sense ssRNA viruses that infect the midgut cells of lepidopteran larvae. Providence virus(PrV) is the only member of the family Carmotetraviridae (previously Tetraviridae). PrV particles exhibit the characteristic tetraviral T=4 icosahedral symmetry, but PrV is distinct from other tetraviruses with respect to genome organization and viral non-structural proteins. Currently, PrV is the only tetravirus known to infect and replicate in lepidopteran cell culture lines. In this report we demonstrate, using immunofluorescence microscopy, that PrV infects and replicates in a human tissue culture cell line (HeLa), producing infectious virus particles. We also provide evidence for PrV replication in vitro in insect, mammalian and plant cell-free systems. This study challenges the long-held view that tetraviruses have a narrow host range confined to one or a few lepidopteran species and highlights the need to consider the potential for apparently non-infectious viruses to be transferred to new hosts in the laboratory.
- Full Text: false
- Date Issued: 2016
- Authors: Jiwaji, Meesbah , Short, James R , Dorrington, Rosemary A
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/65979 , vital:28874 , https://doi.org/10.1099/jgv.0.000578
- Description: publisher version , Tetraviruses are small, positive (+ve)-sense ssRNA viruses that infect the midgut cells of lepidopteran larvae. Providence virus(PrV) is the only member of the family Carmotetraviridae (previously Tetraviridae). PrV particles exhibit the characteristic tetraviral T=4 icosahedral symmetry, but PrV is distinct from other tetraviruses with respect to genome organization and viral non-structural proteins. Currently, PrV is the only tetravirus known to infect and replicate in lepidopteran cell culture lines. In this report we demonstrate, using immunofluorescence microscopy, that PrV infects and replicates in a human tissue culture cell line (HeLa), producing infectious virus particles. We also provide evidence for PrV replication in vitro in insect, mammalian and plant cell-free systems. This study challenges the long-held view that tetraviruses have a narrow host range confined to one or a few lepidopteran species and highlights the need to consider the potential for apparently non-infectious viruses to be transferred to new hosts in the laboratory.
- Full Text: false
- Date Issued: 2016
Keeping it in the family: coevolution of latrunculid sponges and their dominant bacterial symbionts
- Matcher, Gwynneth F, Waterworth, Samantha C, Walmsley, Tara A, Matsatsa, Tendayi, Parker-Nance, Shirley, Davies-Coleman, Michael T, Dorrington, Rosemary A
- Authors: Matcher, Gwynneth F , Waterworth, Samantha C , Walmsley, Tara A , Matsatsa, Tendayi , Parker-Nance, Shirley , Davies-Coleman, Michael T , Dorrington, Rosemary A
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/65603 , vital:28818 , https://doi.org/10.1002/mbo3.417
- Description: publisher version , The Latrunculiidae are a family of cold water sponges known for their production of bioactive pyrroloiminoquinone alkaloids. Previously it was shown that the bacterial community associated with a Tsitsikamma sponge species comprises unusual bacterial taxa and is dominated by a novel Betaproteobacterium. Here, we have characterized the bacterial communities associated with six latrunculid species representing three genera (Tsitsikamma, Cyclacanthia, and Latrunculia) as well as a Mycale species, collected from Algoa Bay on the South African southeast coast. The bacterial communities of all seven sponge species were dominated by a single Betaproteobacterium operational taxonomic unit (OTU0.03), while a second OTU0.03 was dominant in the Mycale sp. The Betaproteobacteria OTUs from the different latrunculid sponges are closely related and their phylogenetic relationship follows that of their hosts. We propose that the latrunculid Betaproteobacteria OTUs are members of a specialized group of sponge symbionts that may have coevolved with their hosts. A single dominant Spirochaetae OTU0.03 was present in the Tsitsikamma and Cyclacanthia sponge species, but absent from the Latrunculia and Mycale sponges. This study sheds new light on the interactions between latrunculid sponges and their bacterial communities and may point to the potential involvement of dominant symbionts in the biosynthesis of the bioactive secondary metabolites. , This research was supported by a SARChI grant from the South African National Research Foundation (NRF, GUN: 87583) and the Rhodes University Sandisa Imbewu Programme. S. C. W. was supported by an NRF Innovation PhD Scholarship and a Rhodes University Henderson PhD Scholarship. T. A. W. was supported by PhD Fellowships from the NRF and the German Academic Exchange Service (DAAD)
- Full Text:
- Date Issued: 2016
- Authors: Matcher, Gwynneth F , Waterworth, Samantha C , Walmsley, Tara A , Matsatsa, Tendayi , Parker-Nance, Shirley , Davies-Coleman, Michael T , Dorrington, Rosemary A
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/65603 , vital:28818 , https://doi.org/10.1002/mbo3.417
- Description: publisher version , The Latrunculiidae are a family of cold water sponges known for their production of bioactive pyrroloiminoquinone alkaloids. Previously it was shown that the bacterial community associated with a Tsitsikamma sponge species comprises unusual bacterial taxa and is dominated by a novel Betaproteobacterium. Here, we have characterized the bacterial communities associated with six latrunculid species representing three genera (Tsitsikamma, Cyclacanthia, and Latrunculia) as well as a Mycale species, collected from Algoa Bay on the South African southeast coast. The bacterial communities of all seven sponge species were dominated by a single Betaproteobacterium operational taxonomic unit (OTU0.03), while a second OTU0.03 was dominant in the Mycale sp. The Betaproteobacteria OTUs from the different latrunculid sponges are closely related and their phylogenetic relationship follows that of their hosts. We propose that the latrunculid Betaproteobacteria OTUs are members of a specialized group of sponge symbionts that may have coevolved with their hosts. A single dominant Spirochaetae OTU0.03 was present in the Tsitsikamma and Cyclacanthia sponge species, but absent from the Latrunculia and Mycale sponges. This study sheds new light on the interactions between latrunculid sponges and their bacterial communities and may point to the potential involvement of dominant symbionts in the biosynthesis of the bioactive secondary metabolites. , This research was supported by a SARChI grant from the South African National Research Foundation (NRF, GUN: 87583) and the Rhodes University Sandisa Imbewu Programme. S. C. W. was supported by an NRF Innovation PhD Scholarship and a Rhodes University Henderson PhD Scholarship. T. A. W. was supported by PhD Fellowships from the NRF and the German Academic Exchange Service (DAAD)
- Full Text:
- Date Issued: 2016
A cytotoxic pentadecapeptide from a South African Didemnid tunicate
- Gallegos, D, Serrill, J, Parker-Nance, Shirley, Dorrington, Rosemary A, Ishmael, J, McPhail, Kerry L
- Authors: Gallegos, D , Serrill, J , Parker-Nance, Shirley , Dorrington, Rosemary A , Ishmael, J , McPhail, Kerry L
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/65935 , vital:28863 , https://doi.org/10.1055/s-0036-1596683
- Description: publisher version , The rate of discovery of new natural product chemical entities has plateaued, and unique populations of endemic, biologically diverse sessile marine organisms represent increasingly critical opportunities to discover new chemistry. Discovery of the mandelalides [1] as potent inhibitors of cancer cell growth from the new South African tunicate Lissoclinum mandelai is an example of the diverse suites of metabolites with potent biological activities that have been isolated from tunicates and other filter-feeding sessile marine organisms that house complex microbial consortia. Further investigation of archived and new tunicate collections from Algoa Bay, South Africa, has revealed a group of didemnid tunicates with an unusual gelatinous morphology similar to Lissoclinum mandelai. Using a bioassay-guided isolation approach, a new “gelatinous” species of the genus Didemnum has yielded a cytotoxic pentadecapeptide with a molecular mass of 1603.7688 Da, comprising fifteen residues including both proteinogenic and non-proteinogenic amino acids. The pure compound inhibited both HeLa cervical cancer and NCI-H460 non-small cell lung cancer cell lines when tested at 30 nM in preliminary assays against cells seeded at low densities. Inhibition of cancer cells at low starting density may be indicative of an anti-proliferative mechanism of action. The compound did not show antibacterial activity against Vibrio cholera. Didemnin B and its clinically approved analogue dehydrodidemnin B (plitidepsin, Aplidin®) [2, 3] are important macrocyclic depsipeptides from a didemnid tunicate. The pentadecapeptide reported here provides justification for our continued investigation of unique, endemic didemnid tunicates from South Africa as a source of new macrocyclic natural products with cytotoxic, anti-viral or antimicrobial activity. , We acknowledge the South African government for permission to collect the subject tunicate (Collection Permit No. 278 RES2013/43)
- Full Text: false
- Date Issued: 2016
- Authors: Gallegos, D , Serrill, J , Parker-Nance, Shirley , Dorrington, Rosemary A , Ishmael, J , McPhail, Kerry L
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/65935 , vital:28863 , https://doi.org/10.1055/s-0036-1596683
- Description: publisher version , The rate of discovery of new natural product chemical entities has plateaued, and unique populations of endemic, biologically diverse sessile marine organisms represent increasingly critical opportunities to discover new chemistry. Discovery of the mandelalides [1] as potent inhibitors of cancer cell growth from the new South African tunicate Lissoclinum mandelai is an example of the diverse suites of metabolites with potent biological activities that have been isolated from tunicates and other filter-feeding sessile marine organisms that house complex microbial consortia. Further investigation of archived and new tunicate collections from Algoa Bay, South Africa, has revealed a group of didemnid tunicates with an unusual gelatinous morphology similar to Lissoclinum mandelai. Using a bioassay-guided isolation approach, a new “gelatinous” species of the genus Didemnum has yielded a cytotoxic pentadecapeptide with a molecular mass of 1603.7688 Da, comprising fifteen residues including both proteinogenic and non-proteinogenic amino acids. The pure compound inhibited both HeLa cervical cancer and NCI-H460 non-small cell lung cancer cell lines when tested at 30 nM in preliminary assays against cells seeded at low densities. Inhibition of cancer cells at low starting density may be indicative of an anti-proliferative mechanism of action. The compound did not show antibacterial activity against Vibrio cholera. Didemnin B and its clinically approved analogue dehydrodidemnin B (plitidepsin, Aplidin®) [2, 3] are important macrocyclic depsipeptides from a didemnid tunicate. The pentadecapeptide reported here provides justification for our continued investigation of unique, endemic didemnid tunicates from South Africa as a source of new macrocyclic natural products with cytotoxic, anti-viral or antimicrobial activity. , We acknowledge the South African government for permission to collect the subject tunicate (Collection Permit No. 278 RES2013/43)
- Full Text: false
- Date Issued: 2016
Stromatolite microbial communities as a source of new bioactive secondary metabolites
- Flatt, P M, Damarjanan, C, Isamonger, E, Kalinski, Jarmo-Charles J, Dorrington, Rosemary A, McPhail, Kerry L
- Authors: Flatt, P M , Damarjanan, C , Isamonger, E , Kalinski, Jarmo-Charles J , Dorrington, Rosemary A , McPhail, Kerry L
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/65871 , vital:28851 , https://doi.org/10.1055/s-0036-1596638
- Description: publisher version , Stromatolites represent some of the earliest microbial communities on Earth. They are formed by accretion and precipitation of layered calcium carbonate structures that result from the metabolic activity of complex microbial communities and the geochemical conditions of their environment. Modern stromatolite communities include aerobic heterotrophs, sulphide-oxidizing bacteria, sulphate-reducing bacteria, fermentative bacteria and cyanobacteria. Phylogenetic analyses revealed the presence of new and known cyanobacterial taxa related to known producers of biologically active secondary metabolites in tufa stromatolites along the South African southeast coast [1]. Prompted us to investigate their potential for producing novel bioactive secondary metabolites. A series of three tide pools provided the opportunity to collect stromatolites along a vertical transect from pool A (highest elevation, low nitrogen input, fresh water), pool B (within high tide zone, brackish water) and pool C (within tidal zone). The microbial community in pool A is particularly distinct. Chemical extracts of stromatolites from different pools have been profiled by LC-MS/MS and the data subjected to molecular spectral networking using the GnPS platform [2] in order to establish the diversity and biological potential of the microbial metabolome that is being expressed within each of these microhabitats. Correlation of the phylogenetic and secondary metabolomic data is expected to guide the isolation of new natural products with biomedical relevance.
- Full Text: false
- Date Issued: 2016
- Authors: Flatt, P M , Damarjanan, C , Isamonger, E , Kalinski, Jarmo-Charles J , Dorrington, Rosemary A , McPhail, Kerry L
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/65871 , vital:28851 , https://doi.org/10.1055/s-0036-1596638
- Description: publisher version , Stromatolites represent some of the earliest microbial communities on Earth. They are formed by accretion and precipitation of layered calcium carbonate structures that result from the metabolic activity of complex microbial communities and the geochemical conditions of their environment. Modern stromatolite communities include aerobic heterotrophs, sulphide-oxidizing bacteria, sulphate-reducing bacteria, fermentative bacteria and cyanobacteria. Phylogenetic analyses revealed the presence of new and known cyanobacterial taxa related to known producers of biologically active secondary metabolites in tufa stromatolites along the South African southeast coast [1]. Prompted us to investigate their potential for producing novel bioactive secondary metabolites. A series of three tide pools provided the opportunity to collect stromatolites along a vertical transect from pool A (highest elevation, low nitrogen input, fresh water), pool B (within high tide zone, brackish water) and pool C (within tidal zone). The microbial community in pool A is particularly distinct. Chemical extracts of stromatolites from different pools have been profiled by LC-MS/MS and the data subjected to molecular spectral networking using the GnPS platform [2] in order to establish the diversity and biological potential of the microbial metabolome that is being expressed within each of these microhabitats. Correlation of the phylogenetic and secondary metabolomic data is expected to guide the isolation of new natural products with biomedical relevance.
- Full Text: false
- Date Issued: 2016
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
SEAmester – South Africa’s first class afloat
- Ansorge, Isabelle J, Brundrit, Geoff, Brundrit, Jean, Dorrington, Rosemary A, Fawcett, Sarah, Gammon, David, Henry, Tahlia, Hermes, Juliet, Hölscher, Beate, d’Hotman, Jethan, Meiklejohn, Ian, Morris, Tammy, Pinto, Izidine, Du Plessis, Marcel, Roman, Raymond, Saunders, Clinton, Shabangu, Fannie W, De Vos, Marc, Walker, David R, Louw, Gavin
- Authors: Ansorge, Isabelle J , Brundrit, Geoff , Brundrit, Jean , Dorrington, Rosemary A , Fawcett, Sarah , Gammon, David , Henry, Tahlia , Hermes, Juliet , Hölscher, Beate , d’Hotman, Jethan , Meiklejohn, Ian , Morris, Tammy , Pinto, Izidine , Du Plessis, Marcel , Roman, Raymond , Saunders, Clinton , Shabangu, Fannie W , De Vos, Marc , Walker, David R , Louw, Gavin
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/65539 , vital:28808 , https://doi.org/10.17159/sajs.2016/a0171
- Description: publisher version , From Introduction: Marine science is a highly competitive environment. The need to improve the cohort of South African postgraduates, who would be recognised both nationally and internationally for their scientific excellence, is crucial. It is possible to attract students early on in their careers to this discipline via cutting-edge science, technology and unique field experiences. Through the engagement of students with real-life experiences such as SEAmester, universities supporting marine science postgraduate degree programmes can attract a sustainable throughput of numerically proficient students. By achieving a more quantitative and experienced input into our postgraduate degree programmes, we will, as a scientific community, greatly improve our long-term capabilities to accurately measure, model and predict the impacts of current climate change scenarios. The short-term goal is to attract and establish a cohort of proficient marine and atmospheric science graduates who will contribute to filling the capacity needs of South African marine science as a whole. The SEAmester programme, by involving researchers from across all the relevant disciplines and tertiary institutions, provides an opportunity to build a network of collaborative teaching within the marine field. In doing so, these researchers will foster and strengthen new and current collaborations between historically white and black universities (Figure 1). The long-term objective of SEAmester is to build critical mass within the marine sciences to ensure sustained growth of human capacity in marine science in South Africa – aligning closely with the current DST Research and Development strategies and the Operation Phakisa Oceans Economy initiative.
- Full Text:
- Date Issued: 2016
- Authors: Ansorge, Isabelle J , Brundrit, Geoff , Brundrit, Jean , Dorrington, Rosemary A , Fawcett, Sarah , Gammon, David , Henry, Tahlia , Hermes, Juliet , Hölscher, Beate , d’Hotman, Jethan , Meiklejohn, Ian , Morris, Tammy , Pinto, Izidine , Du Plessis, Marcel , Roman, Raymond , Saunders, Clinton , Shabangu, Fannie W , De Vos, Marc , Walker, David R , Louw, Gavin
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/65539 , vital:28808 , https://doi.org/10.17159/sajs.2016/a0171
- Description: publisher version , From Introduction: Marine science is a highly competitive environment. The need to improve the cohort of South African postgraduates, who would be recognised both nationally and internationally for their scientific excellence, is crucial. It is possible to attract students early on in their careers to this discipline via cutting-edge science, technology and unique field experiences. Through the engagement of students with real-life experiences such as SEAmester, universities supporting marine science postgraduate degree programmes can attract a sustainable throughput of numerically proficient students. By achieving a more quantitative and experienced input into our postgraduate degree programmes, we will, as a scientific community, greatly improve our long-term capabilities to accurately measure, model and predict the impacts of current climate change scenarios. The short-term goal is to attract and establish a cohort of proficient marine and atmospheric science graduates who will contribute to filling the capacity needs of South African marine science as a whole. The SEAmester programme, by involving researchers from across all the relevant disciplines and tertiary institutions, provides an opportunity to build a network of collaborative teaching within the marine field. In doing so, these researchers will foster and strengthen new and current collaborations between historically white and black universities (Figure 1). The long-term objective of SEAmester is to build critical mass within the marine sciences to ensure sustained growth of human capacity in marine science in South Africa – aligning closely with the current DST Research and Development strategies and the Operation Phakisa Oceans Economy initiative.
- Full Text:
- Date Issued: 2016
Conserved bacterial genomes from two geographically isolated peritidal stromatolite formations shed light on potential functional guilds
- Waterworth, Samantha C, Isemonger, Eric W, Rees, Evan R, Dorrington, Rosemary A
- Authors: Waterworth, Samantha C , Isemonger, Eric W , Rees, Evan R , Dorrington, Rosemary A
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429411 , vital:72608 , xlink:href="https://doi.org/10.1111/1758-2229.12916"
- Description: Stromatolites are complex microbial mats that form lithified layers. Fossilized stromatolites are the oldest evidence of cellular life on Earth, dating back over3.4 billion years. Modern stromatolites are relatively rare but may provide clues about the function and evolution of their ancient counterparts. In this study, we focus on peritidal stromatolites occurring at Cape Recife and Schoenmakerskop on the southeastern South African coastline, the former being morphologically and structurally similar to fossilized phosphatic stromatolites formations. Using assembled shotgun metagenomic analysis, we obtained 183 genomic bins, of which the most dominant taxa were from the Cyanobacteria phylum. We identified functional gene sets in genomic bins conserved across two geographically isolated stromatolite formations, which included relatively high copy numbers of genes involved in the reduction of nitrates and phosphatic compounds. Additionally, we found little evidence of Archaeal species in these stromatolites, suggesting that they may not play an important role in peritidal stromatolite formations, as proposed for hypersaline formations.
- Full Text:
- Date Issued: 2020
- Authors: Waterworth, Samantha C , Isemonger, Eric W , Rees, Evan R , Dorrington, Rosemary A
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429411 , vital:72608 , xlink:href="https://doi.org/10.1111/1758-2229.12916"
- Description: Stromatolites are complex microbial mats that form lithified layers. Fossilized stromatolites are the oldest evidence of cellular life on Earth, dating back over3.4 billion years. Modern stromatolites are relatively rare but may provide clues about the function and evolution of their ancient counterparts. In this study, we focus on peritidal stromatolites occurring at Cape Recife and Schoenmakerskop on the southeastern South African coastline, the former being morphologically and structurally similar to fossilized phosphatic stromatolites formations. Using assembled shotgun metagenomic analysis, we obtained 183 genomic bins, of which the most dominant taxa were from the Cyanobacteria phylum. We identified functional gene sets in genomic bins conserved across two geographically isolated stromatolite formations, which included relatively high copy numbers of genes involved in the reduction of nitrates and phosphatic compounds. Additionally, we found little evidence of Archaeal species in these stromatolites, suggesting that they may not play an important role in peritidal stromatolite formations, as proposed for hypersaline formations.
- Full Text:
- Date Issued: 2020
Living phosphatic stromatolites in a low-phosphorus environment: Implications for the use of phosphorus as a proxy for phosphate levels in paleosystems
- Buttner, Steffen H, Isemonger, Eric W, Isaacs, Michelle, van Niekerk, Deon, Sipler, Rachel E, Dorrington, Rosemary A
- Authors: Buttner, Steffen H , Isemonger, Eric W , Isaacs, Michelle , van Niekerk, Deon , Sipler, Rachel E , Dorrington, Rosemary A
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429450 , vital:72611 , xlink:href="https://doi.org/10.1111/gbi.12415"
- Description: In the geological record, fossil phosphatic stromatolites date back to the Great Oxidation Event in the Paleoproterozoic, but living phosphatic stromatolites have not been described previously. Here, we report on cyanobacterial stromatolites in a supratidal freshwater environment at Cape Recife, South African southern coast, precipitating Ca carbonate alternating with episodes of Ca phosphate deposition. In their structure and composition, the living stromatolites from Cape Recife closely resemble their fossilized analogues, showing phosphatic zonation, microbial casts, tunnel structures and phosphatic crusts of biogenic origin. The microbial communities appear to be also similar to those proposed to have formed fossil phosphatic stromatolites. Phosphatic domains in the material from Cape Recife are spatially and texturally associated with carbonate precipitates, but form distinct entities separated by sharp boundaries. Electron Probe Micro-Analysis shows that Ca/P ratios and the overall chemical compositions of phosphatic precipitates are in the range of octacalcium phosphate, amorphous tricalcium phosphate and apatite. The coincidence in time of the emergence of phosphatic stromatolites in the fossil record with a major episode of atmospheric oxidation led to the assumption that at times of increased oxygen release the underlying increased biological production may have been linked to elevated phosphorus availability. The stromatolites at Cape Recife, however, form in an environment where ambient phosphorus concentrations do not exceed 0.28μM, one to two orders of magnitude below the previously predicted minimum thresh-old of >5 μM for biogenic phosphate precipitation in paleo-systems. Accordingly, we contest the previously proposed suitability of phosphatic stromatolites as a proxy for high ambient phosphate concentrations in supratidal to shallow ocean settings in earth history.
- Full Text:
- Date Issued: 2020
- Authors: Buttner, Steffen H , Isemonger, Eric W , Isaacs, Michelle , van Niekerk, Deon , Sipler, Rachel E , Dorrington, Rosemary A
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429450 , vital:72611 , xlink:href="https://doi.org/10.1111/gbi.12415"
- Description: In the geological record, fossil phosphatic stromatolites date back to the Great Oxidation Event in the Paleoproterozoic, but living phosphatic stromatolites have not been described previously. Here, we report on cyanobacterial stromatolites in a supratidal freshwater environment at Cape Recife, South African southern coast, precipitating Ca carbonate alternating with episodes of Ca phosphate deposition. In their structure and composition, the living stromatolites from Cape Recife closely resemble their fossilized analogues, showing phosphatic zonation, microbial casts, tunnel structures and phosphatic crusts of biogenic origin. The microbial communities appear to be also similar to those proposed to have formed fossil phosphatic stromatolites. Phosphatic domains in the material from Cape Recife are spatially and texturally associated with carbonate precipitates, but form distinct entities separated by sharp boundaries. Electron Probe Micro-Analysis shows that Ca/P ratios and the overall chemical compositions of phosphatic precipitates are in the range of octacalcium phosphate, amorphous tricalcium phosphate and apatite. The coincidence in time of the emergence of phosphatic stromatolites in the fossil record with a major episode of atmospheric oxidation led to the assumption that at times of increased oxygen release the underlying increased biological production may have been linked to elevated phosphorus availability. The stromatolites at Cape Recife, however, form in an environment where ambient phosphorus concentrations do not exceed 0.28μM, one to two orders of magnitude below the previously predicted minimum thresh-old of >5 μM for biogenic phosphate precipitation in paleo-systems. Accordingly, we contest the previously proposed suitability of phosphatic stromatolites as a proxy for high ambient phosphate concentrations in supratidal to shallow ocean settings in earth history.
- Full Text:
- Date Issued: 2020
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