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Xinyu Liu - One of the best experts on this subject based on the ideXlab platform.
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characterization of non heme iron aliphatic halogenase welo5 fromhapalosiphon welwitschiiic 52 3 identification of a minimal protein sequence motif that confers enzymatic chlorination specificity in the biosynthesis of welwitindolelinones
Beilstein Journal of Organic Chemistry, 2017Co-Authors: Qin Zhu, Xinyu LiuAbstract:The in vitro biochemical characterization revealed that iron/2-oxoglutarate (Fe/2OG)-dependent aliphatic halogenase WelO5* in Hapalosiphon welwitschii IC-52-3 has an enhanced substrate specificity towards 12-epi-hapalindole C (1) in comparison to WelO5 in H. welwitschii UTEX B1830. This allowed us to define the origin of the varied chlorinated versus dechlorinated alkaloid structural diversity between the two welwitindolinone producers. Furthermore, this study, along with the recent characterization of the AmbO5 protein, collectively confirmed the presence of a signature sequence motif in the C-terminus of this newly discovered halogenase enzyme family that confers substrate promiscuity and specificity. These observations may guide the rational engineering and evolution of these proteins for biocatalyst application.
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characterization of non heme iron aliphatic halogenase welo5 from hapalosiphon welwitschii ic 52 3 identification of a minimal protein sequence motif that confers enzymatic chlorination specificity in the biosynthesis of welwitindolelinones
Beilstein Journal of Organic Chemistry, 2017Co-Authors: Qin Zhu, Xinyu LiuAbstract:The in vitro biochemical characterization revealed that iron/2-oxoglutarate (Fe/2OG)-dependent aliphatic halogenase WelO5* in Hapalosiphon welwitschii IC-52-3 has an enhanced substrate specificity towards 12-epi-hapalindole C (1) in comparison to WelO5 in H. welwitschii UTEX B1830. This allowed us to define the origin of the varied chlorinated versus dechlorinated alkaloid structural diversity between the two welwitindolinone producers. Furthermore, this study, along with the recent characterization of the AmbO5 protein, collectively confirmed the presence of a signature sequence motif in the C-terminus of this newly discovered halogenase enzyme family that confers substrate promiscuity and specificity. These observations may guide the rational engineering and evolution of these proteins for biocatalyst application.
Qin Zhu - One of the best experts on this subject based on the ideXlab platform.
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characterization of non heme iron aliphatic halogenase welo5 fromhapalosiphon welwitschiiic 52 3 identification of a minimal protein sequence motif that confers enzymatic chlorination specificity in the biosynthesis of welwitindolelinones
Beilstein Journal of Organic Chemistry, 2017Co-Authors: Qin Zhu, Xinyu LiuAbstract:The in vitro biochemical characterization revealed that iron/2-oxoglutarate (Fe/2OG)-dependent aliphatic halogenase WelO5* in Hapalosiphon welwitschii IC-52-3 has an enhanced substrate specificity towards 12-epi-hapalindole C (1) in comparison to WelO5 in H. welwitschii UTEX B1830. This allowed us to define the origin of the varied chlorinated versus dechlorinated alkaloid structural diversity between the two welwitindolinone producers. Furthermore, this study, along with the recent characterization of the AmbO5 protein, collectively confirmed the presence of a signature sequence motif in the C-terminus of this newly discovered halogenase enzyme family that confers substrate promiscuity and specificity. These observations may guide the rational engineering and evolution of these proteins for biocatalyst application.
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characterization of non heme iron aliphatic halogenase welo5 from hapalosiphon welwitschii ic 52 3 identification of a minimal protein sequence motif that confers enzymatic chlorination specificity in the biosynthesis of welwitindolelinones
Beilstein Journal of Organic Chemistry, 2017Co-Authors: Qin Zhu, Xinyu LiuAbstract:The in vitro biochemical characterization revealed that iron/2-oxoglutarate (Fe/2OG)-dependent aliphatic halogenase WelO5* in Hapalosiphon welwitschii IC-52-3 has an enhanced substrate specificity towards 12-epi-hapalindole C (1) in comparison to WelO5 in H. welwitschii UTEX B1830. This allowed us to define the origin of the varied chlorinated versus dechlorinated alkaloid structural diversity between the two welwitindolinone producers. Furthermore, this study, along with the recent characterization of the AmbO5 protein, collectively confirmed the presence of a signature sequence motif in the C-terminus of this newly discovered halogenase enzyme family that confers substrate promiscuity and specificity. These observations may guide the rational engineering and evolution of these proteins for biocatalyst application.
Xiaoquan Wang - One of the best experts on this subject based on the ideXlab platform.
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the complete mitochondrial genome of taxus cuspidata taxaceae eight protein coding genes have transferred to the nuclear genome
BMC Evolutionary Biology, 2020Co-Authors: Shenglong Kan, Tingting Shen, Ping Gong, Jinhua Ran, Xiaoquan WangAbstract:Gymnosperms represent five of the six lineages of seed plants. However, most sequenced plant mitochondrial genomes (mitogenomes) have been generated for angiosperms, whereas mitogenomic sequences have been generated for only six gymnosperms. In particular, complete mitogenomes are available for all major seed plant lineages except Conifer II (non-Pinaceae conifers or Cupressophyta), an important lineage including six families, which impedes a comprehensive understanding of the mitogenomic diversity and evolution in gymnosperms. Here, we report the complete mitogenome of Taxus cuspidata in Conifer II. In comparison with previously released gymnosperm mitogenomes, we found that the mitogenomes of Taxus and Welwitschia have lost many genes individually, whereas all genes were identified in the mitogenomes of Cycas, Ginkgo and Pinaceae. Multiple tRNA genes and introns also have been lost in some lineages of gymnosperms, similar to the pattern observed in angiosperms. In general, gene clusters could be less conserved in gymnosperms than in angiosperms. Moreover, fewer RNA editing sites were identified in the Taxus and Welwitschia mitogenomes than in other mitogenomes, which could be correlated with fewer introns and frequent gene losses in these two species. We have sequenced the Taxus cuspidata mitogenome, and compared it with mitogenomes from the other four gymnosperm lineages. The results revealed the diversity in size, structure, gene and intron contents, foreign sequences, and mutation rates of gymnosperm mitogenomes, which are different from angiosperm mitogenomes.
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The complete mitochondrial genome of Taxus cuspidata (Taxaceae): eight protein-coding genes have transferred to the nuclear genome
'Springer Science and Business Media LLC', 2020Co-Authors: Shenglong Kan, Tingting Shen, Ping Gong, Jinhua Ran, Xiaoquan WangAbstract:Abstract Background Gymnosperms represent five of the six lineages of seed plants. However, most sequenced plant mitochondrial genomes (mitogenomes) have been generated for angiosperms, whereas mitogenomic sequences have been generated for only six gymnosperms. In particular, complete mitogenomes are available for all major seed plant lineages except Conifer II (non-Pinaceae conifers or Cupressophyta), an important lineage including six families, which impedes a comprehensive understanding of the mitogenomic diversity and evolution in gymnosperms. Results Here, we report the complete mitogenome of Taxus cuspidata in Conifer II. In comparison with previously released gymnosperm mitogenomes, we found that the mitogenomes of Taxus and Welwitschia have lost many genes individually, whereas all genes were identified in the mitogenomes of Cycas, Ginkgo and Pinaceae. Multiple tRNA genes and introns also have been lost in some lineages of gymnosperms, similar to the pattern observed in angiosperms. In general, gene clusters could be less conserved in gymnosperms than in angiosperms. Moreover, fewer RNA editing sites were identified in the Taxus and Welwitschia mitogenomes than in other mitogenomes, which could be correlated with fewer introns and frequent gene losses in these two species. Conclusions We have sequenced the Taxus cuspidata mitogenome, and compared it with mitogenomes from the other four gymnosperm lineages. The results revealed the diversity in size, structure, gene and intron contents, foreign sequences, and mutation rates of gymnosperm mitogenomes, which are different from angiosperm mitogenomes
Theo Wassenaar - One of the best experts on this subject based on the ideXlab platform.
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very high extinction risk for Welwitschia mirabilis in the northern namib desert
Journal of Arid Environments, 2021Co-Authors: Pierluigi Bombi, Daniele Salvi, Titus Shuuya, Leonardo Vignoli, Theo WassenaarAbstract:Abstract One of the most recognizable icons of the Namib Desert is the endemic gymnosperm Welwitschia mirabilis. Recent studies indicated that climate change may seriously affect populations in the northern Namibia subrange (Kunene region), but their extinction risk has not yet been assessed. In this study, we apply IUCN criteria to define the extinction risk of Welwitschia populations in northern Namibia and assign them to a red list category. We collected field data to estimate relevant parameters for this assessment. We observed 1330 plants clustered in 12 small and isolated stands. The extent of occurrence has a surface area of 214.2 km2 (i.e., 50%) as a consequence of climate change predicted in the area. These data indicate a very high extinction risk for Welwitschia in northern Kunene, hence, we classify these populations as endangered (EN) according to IUCN criteria. Similar assessments for other subranges are prevented by the lack of relevant data, an issue that deserves further research attention. Our results advocate the necessity of a management plan for the species, including measures for mitigating the impact of climate change on isolated populations across its fragmented range.
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climate change effects on desert ecosystems a case study on the keystone species of the namib desert Welwitschia mirabilis
PLOS ONE, 2021Co-Authors: Pierluigi Bombi, Daniele Salvi, Titus Shuuya, Leonardo Vignoli, Theo WassenaarAbstract:Deserts have been predicted to be one of the most responsive ecosystems to global climate change. In this study, we examine the spatial and demographic response of a keystone endemic plant of the Namib Desert (Welwitschia mirabilis), for which displacement and reduction of suitable climate has been foreseen under future conditions. The main aim is to assess the association between ongoing climate change and geographical patterns of Welwitschia health, reproductive status, and size. We collected data on Welwitschia distribution, health condition, reproductive status, and plant size in northern Namibia. We used ecological niche models to predict the expected geographic shift of suitability under climate change scenarios. For each variable, we compared our field measurements with the expected ongoing change in climate suitability. Finally, we tested the presence of simple geographical gradients in the observed patterns. The historically realized thermal niche of Welwitschia will be almost completely unavailable in the next 30 years in northern Namibia. Expected reductions of climatic suitability in our study sites were strongly associated with indicators of negative population conditions, namely lower plant health, reduced recruitment and increased adult mortality. Population condition does not follow simple latitudinal or altitudinal gradients. The observed pattern of population traits is consistent with climate change trends and projections. This makes Welwitschia a suitable bioindicator (i.e. a 'sentinel') for climate change effect in the Namib Desert ecosystems. Our spatially explicit approach, combining suitability modeling with geographic combinations of population conditions measured in the field, could be extensively adopted to identify sentinel species, and detect population responses to climate change in other regions and ecosystems.
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very high extinction risk for Welwitschia mirabilis in the northern namib desert
bioRxiv, 2020Co-Authors: Pierluigi Bombi, Daniele Salvi, Titus Shuuya, Leonardo Vignoli, Theo WassenaarAbstract:One of the most recognisable icon of the Namib Desert is the endemic gymnosperm Welwitschia mirabilis. Recent studies indicated that climate change may seriously affect populations in the northern Namibia subrange (Kunene region) but their extinction risk has not yet been assessed. In this study, we apply IUCN criteria to define the extinction risk of Welwitschia populations in northern Namibia and assign them to a red list category. We collected field data in the field to estimate relevant parameters for this assessment. We observed 1330 plants clustered in 12 small and isolated stands. The extent of occurrence has a surface of 214.2 km2 (i.e. 50 %) as a consequence of climate change predicted in the area. These data indicate a very high extinction risk for Welwitschia in northern Kunene and classify these populations as endangered (EN) according to IUCN criteria. Similar assessments for other subranges are prevented by the lack of relevant data, an issue that deserves further research attention. Our results advocate the necessity of a management plan for the species, including measures for mitigating the impact of climate change on isolated populations across its fragmented range.
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evidence of climate change impacts on the iconic Welwitschia mirabilis in the namib desert
bioRxiv, 2020Co-Authors: Pierluigi Bombi, Daniele Salvi, Titus Shuuya, Leonardo Vignoli, Theo WassenaarAbstract:Abstract Climate change represents an important threat to global biodiversity and African ecosystems are particularly vulnerable. Recent studies predicted substantial variations of climatic suitability for Welwitschia mirabilis under future conditions. Latitudinal/altitudinal range shifts are well-known responses to climate change but not coherent patterns were documented. This study aims to verify whether Welwitschia populations are responding to climate change and if the assumption of a latitudinal/altitudinal shift is applicable. We collected field data on Welwitschia distribution, health condition, reproductive status, and plant size in northern Namibia. We used ecological niche models to predict the expected geographic shift of climatic suitability under future scenarios. For each variable, we compared the observed pattern with the expected responses. Finally, we tested the presence of simple geographical gradients in the observed patterns. The realized thermal niche of Welwitschia will be almost completely unavailable in the next 30 years in northern Namibia. Expected reductions of climatic suitability in the stand sites are strongly associated with indicators of negative population conditions. The same population conditions does not fit any simple latitudinal or altitudinal gradient. The observed pattern of population conditions mirrors the expected pattern of climate change effect but no simple geographical gradient was relieved. Overall, we observed negative population conditions in areas with stronger reductions of suitability. This makes Welwitschia a suitable sentinel for climate change effect in the Namib Desert ecosystems. Our approach to detect population responses to climate change could be extensively adopted for selecting sentinel species in other regions and ecosystems.
Pierluigi Bombi - One of the best experts on this subject based on the ideXlab platform.
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very high extinction risk for Welwitschia mirabilis in the northern namib desert
Journal of Arid Environments, 2021Co-Authors: Pierluigi Bombi, Daniele Salvi, Titus Shuuya, Leonardo Vignoli, Theo WassenaarAbstract:Abstract One of the most recognizable icons of the Namib Desert is the endemic gymnosperm Welwitschia mirabilis. Recent studies indicated that climate change may seriously affect populations in the northern Namibia subrange (Kunene region), but their extinction risk has not yet been assessed. In this study, we apply IUCN criteria to define the extinction risk of Welwitschia populations in northern Namibia and assign them to a red list category. We collected field data to estimate relevant parameters for this assessment. We observed 1330 plants clustered in 12 small and isolated stands. The extent of occurrence has a surface area of 214.2 km2 (i.e., 50%) as a consequence of climate change predicted in the area. These data indicate a very high extinction risk for Welwitschia in northern Kunene, hence, we classify these populations as endangered (EN) according to IUCN criteria. Similar assessments for other subranges are prevented by the lack of relevant data, an issue that deserves further research attention. Our results advocate the necessity of a management plan for the species, including measures for mitigating the impact of climate change on isolated populations across its fragmented range.
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climate change effects on desert ecosystems a case study on the keystone species of the namib desert Welwitschia mirabilis
PLOS ONE, 2021Co-Authors: Pierluigi Bombi, Daniele Salvi, Titus Shuuya, Leonardo Vignoli, Theo WassenaarAbstract:Deserts have been predicted to be one of the most responsive ecosystems to global climate change. In this study, we examine the spatial and demographic response of a keystone endemic plant of the Namib Desert (Welwitschia mirabilis), for which displacement and reduction of suitable climate has been foreseen under future conditions. The main aim is to assess the association between ongoing climate change and geographical patterns of Welwitschia health, reproductive status, and size. We collected data on Welwitschia distribution, health condition, reproductive status, and plant size in northern Namibia. We used ecological niche models to predict the expected geographic shift of suitability under climate change scenarios. For each variable, we compared our field measurements with the expected ongoing change in climate suitability. Finally, we tested the presence of simple geographical gradients in the observed patterns. The historically realized thermal niche of Welwitschia will be almost completely unavailable in the next 30 years in northern Namibia. Expected reductions of climatic suitability in our study sites were strongly associated with indicators of negative population conditions, namely lower plant health, reduced recruitment and increased adult mortality. Population condition does not follow simple latitudinal or altitudinal gradients. The observed pattern of population traits is consistent with climate change trends and projections. This makes Welwitschia a suitable bioindicator (i.e. a 'sentinel') for climate change effect in the Namib Desert ecosystems. Our spatially explicit approach, combining suitability modeling with geographic combinations of population conditions measured in the field, could be extensively adopted to identify sentinel species, and detect population responses to climate change in other regions and ecosystems.
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very high extinction risk for Welwitschia mirabilis in the northern namib desert
bioRxiv, 2020Co-Authors: Pierluigi Bombi, Daniele Salvi, Titus Shuuya, Leonardo Vignoli, Theo WassenaarAbstract:One of the most recognisable icon of the Namib Desert is the endemic gymnosperm Welwitschia mirabilis. Recent studies indicated that climate change may seriously affect populations in the northern Namibia subrange (Kunene region) but their extinction risk has not yet been assessed. In this study, we apply IUCN criteria to define the extinction risk of Welwitschia populations in northern Namibia and assign them to a red list category. We collected field data in the field to estimate relevant parameters for this assessment. We observed 1330 plants clustered in 12 small and isolated stands. The extent of occurrence has a surface of 214.2 km2 (i.e. 50 %) as a consequence of climate change predicted in the area. These data indicate a very high extinction risk for Welwitschia in northern Kunene and classify these populations as endangered (EN) according to IUCN criteria. Similar assessments for other subranges are prevented by the lack of relevant data, an issue that deserves further research attention. Our results advocate the necessity of a management plan for the species, including measures for mitigating the impact of climate change on isolated populations across its fragmented range.
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evidence of climate change impacts on the iconic Welwitschia mirabilis in the namib desert
bioRxiv, 2020Co-Authors: Pierluigi Bombi, Daniele Salvi, Titus Shuuya, Leonardo Vignoli, Theo WassenaarAbstract:Abstract Climate change represents an important threat to global biodiversity and African ecosystems are particularly vulnerable. Recent studies predicted substantial variations of climatic suitability for Welwitschia mirabilis under future conditions. Latitudinal/altitudinal range shifts are well-known responses to climate change but not coherent patterns were documented. This study aims to verify whether Welwitschia populations are responding to climate change and if the assumption of a latitudinal/altitudinal shift is applicable. We collected field data on Welwitschia distribution, health condition, reproductive status, and plant size in northern Namibia. We used ecological niche models to predict the expected geographic shift of climatic suitability under future scenarios. For each variable, we compared the observed pattern with the expected responses. Finally, we tested the presence of simple geographical gradients in the observed patterns. The realized thermal niche of Welwitschia will be almost completely unavailable in the next 30 years in northern Namibia. Expected reductions of climatic suitability in the stand sites are strongly associated with indicators of negative population conditions. The same population conditions does not fit any simple latitudinal or altitudinal gradient. The observed pattern of population conditions mirrors the expected pattern of climate change effect but no simple geographical gradient was relieved. Overall, we observed negative population conditions in areas with stronger reductions of suitability. This makes Welwitschia a suitable sentinel for climate change effect in the Namib Desert ecosystems. Our approach to detect population responses to climate change could be extensively adopted for selecting sentinel species in other regions and ecosystems.
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Potential impacts of climate change on Welwitschia mirabilis populations in the Namib Desert, southern Africa
Journal of Arid Land, 2018Co-Authors: Pierluigi BombiAbstract:Climate change is threatening natural ecosystems in the Earth, and arid regions of southern Africa are particularly exposed to further drying. Welwitschia mirabilis Hook. (Welwitschiaceae) is an unusual gymnosperm tree that is recognized as an icon of the Namib Desert, southern Africa. Many aspects of its biology were investigated in the past, with a special emphasis for its physiology and adaptations, but nothing is known about its potential sensitivity to current climate changes. In this study, we adopted an approach based on distribution data for W. mirabilis and ecological niche models for clarifying the species-climate interactions and for predicting the potential impacts of climate change on W. mirabilis populations in three well-separated sub-ranges (northern, southern and central) in northwestern Namibia, southern Africa. We evidenced that the populations occurring in the northern sub-range have peculiar climatic exigencies compared with those in the central and southern sub-ranges and are particularly exposed to the impact of climate change, which will consist of a substantial increase in temperature across the region. These impacts could be represented by demographic changes that should be detected and monitored detailedly to plan efficient measures for managing populations of this important species on the long-term scale.
