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Maximilian Weigend - One of the best experts on this subject based on the ideXlab platform.
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Distribution, Ecology, Chemistry and Toxicology of Plant Stinging Hairs
Toxins, 2021Co-Authors: Hans-jürgen Ensikat, Hannah Wessely, Marianne Engeser, Maximilian WeigendAbstract:Plant Stinging Hairs have fascinated humans for time immemorial. True Stinging Hairs are highly specialized plant structures that are able to inject a physiologically active liquid into the skin and can be differentiated from irritant Hairs (causing mechanical damage only). Stinging Hairs can be classified into two basic types: Urtica-type Stinging Hairs with the classical "hypodermic syringe" mechanism expelling only liquid, and Tragia-type Stinging Hairs expelling a liquid together with a sharp crystal. In total, there are some 650 plant species with Stinging Hairs across five remotely related plant families (i.e., belonging to different plant orders). The family Urticaceae (order Rosales) includes a total of ca. 150 Stinging representatives, amongst them the well-known Stinging nettles (genus Urtica). There are also some 200 Stinging species in Loasaceae (order Cornales), ca. 250 Stinging species in Euphorbiaceae (order Malphigiales), a handful of species in Namaceae (order Boraginales), and one in Caricaceae (order Brassicales). Stinging Hairs are commonly found on most aerial parts of the plants, especially the stem and leaves, but sometimes also on flowers and fruits. The ecological role of Stinging Hairs in plants seems to be essentially defense against mammalian herbivores, while they appear to be essentially inefficient against invertebrate pests. Stinging plants are therefore frequent pasture weeds across different taxa and geographical zones. Stinging Hairs are usually combined with additional chemical and/or mechanical defenses in plants and are not a standalone mechanism. The physiological effects of Stinging Hairs on humans vary widely between Stinging plants and range from a slight itch, skin rash (urticaria), and oedema to sharp pain and even serious neurological disorders such as neuropathy. Numerous studies have attempted to elucidate the chemical basis of the physiological effects. Since the middle of the 20th century, neurotransmitters (acetylcholine, histamine, serotonin) have been repeatedly detected in Stinging Hairs of Urticaceae, but recent analyses of Loasaceae Stinging hair fluids revealed high variability in their composition and content of neurotransmitters. These substances can explain some of the physiological effects of Stinging Hairs, but fail to completely explain neuropathic effects, pointing to some yet unidentified neurotoxin. Inorganic ions (e.g., potassium) are detected in Stinging Hairs and could have synergistic effects. Very recently, ultrastable miniproteins dubbed "gympietides" have been reported from two species of Dendrocnide, arguably the most violently Stinging plant. Gympietides are shown to be highly neurotoxic, providing a convincing explanation for Dendrocnide toxicity. For the roughly 648 remaining Stinging plant species, similarly convincing data on toxicity are still lacking.
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Stinging hair morphology and wall biomineralization across five plant families: Conserved morphology versus divergent cell wall composition.
American journal of botany, 2018Co-Authors: Adeel Mustafa, Hans-jürgen Ensikat, Maximilian WeigendAbstract:Premise of the study Stinging Hairs are striking examples of plant microengineering-the plant equivalent of the hypodermic syringe. The requisite mechanical properties are mostly achieved by cell wall mineralization. Stinging Hairs of Urtica dioica (Urticaceae) are known to be mineralized with silica and calcium carbonate and those of Loasaceae also with calcium phosphate, but no comparative study has been provided across different taxa with Stinging Hairs. Methods Light microscopy and scanning electron microscopy (SEM) with cryo-SEM and energy-dispersive x-ray spectroscopy were used to analyze morphology and biomineralization of Stinging Hairs of 43 species from the families Caricaceae, Euphorbiaceae, Loasaceae, Namaceae, and Urticaceae. Key results Stinging hair morphology is similar across the taxa studied, in striking contrast to the divergent patterns of biomineralization. Trichome bases are mostly calcified, sometimes silicified, the shafts are mostly calcified, and the apices silicified (Urticaceae), and contain calcium phosphate (Caricaceae, Namaceae), both silica and calcium phosphate (some Loasaceae), or no minerals (Cnidoscolus, Euphorbiaceae). Some Stinging Hairs are superficially thinly coated with silica over a cell wall otherwise mineralized with calcium carbonate or calcium phosphate. Conclusions Mineralization patterns are surprisingly diverse and involve three different biominerals deposited in different parts of individual trichomes with calcium phosphate a common component. The physical properties of different wall regions of the Stinging trichomes are thus fine-tuned to optimize their function via modulation of wall thickness and differential element deposition. Similar function is apparently achieved through divergent wall compositions.
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Calcium phosphate in plant trichomes: the overlooked biomineral
Planta, 2017Co-Authors: Maximilian Weigend, Adeel Mustafa, Hans-jürgen EnsikatAbstract:Main conclusion Calcium phosphate was unknown as a plant biomineral until recently reported in Neotropical Loasaceae. Here, we demonstrate its widespread occurrence in the trichomes of several plant families, including Brassicaceae. Calcium phosphate is the primary biomineral in, e.g., the bones and teeth of higher animals; in plants, it was only recently discovered in the Stinging Hairs and scabrid–glochidiate trichomes of South American Loasaceae (Ensikat et al. in Sci Rep UK 6:26073, 2016), where it appears to be deposited highly specifically, often replacing the common plant biomineral silica. We initiated a broader survey in a range of different plant orders to investigate a possibly wider distribution of calcium phosphate biomineralization in plants. Scanning electron microscopy with EDX element analysis and mapping was used for the detection of the biominerals: calcium phosphate, calcium carbonate, and silica in the trichomes of several common plant species of different orders. Results were authenticated with Raman spectroscopy. Calcium phosphate was found in the trichomes of several species in the orders Malpighiales, Rosales, Boraginales, and Brassicales. It occurred in trichome tips, replacing the more common silica, or together with silica and calcium carbonate at specific locations in the trichome cell walls. Most surprisingly, it was found in the trichomes of Arabidopsis thaliana, one of the most studied plant species—where it had been overlooked so far. The wide distribution of calcium phosphate as plant biomineral here demonstrated and the striking mineralization patterns with three different biominerals in the walls of single-celled trichomes underscore an unexpected complexity in plant biomineralization.
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Complex patterns of multiple biomineralization in single‐celled plant trichomes of the Loasaceae
American journal of botany, 2017Co-Authors: Hans-jürgen Ensikat, Adeel Mustafa, Maximilian WeigendAbstract:PREMISE OF THE STUDY Plants of the family Loasaceae are characterized by a usually dense indument of various trichome types, including two basically different types of mineralized, unicellular trichomes (Stinging Hairs or setae and scabrid-glochidiate trichomes). Mineralized trichomes have long been known to have silicified or calcified walls, but recent studies demonstrated that trichomes of Loasaceae may also contain calcium phosphate. The current study investigates the distribution of different biominerals in the mineralized trichomes across several different taxa. METHODS Plants from cultivation were studied with scanning electron microscopy including energy dispersive x-ray analyses and element mapping. KEY RESULTS The vast majority of the 31 species investigated had at least two different biominerals in their trichomes, and 22 had three different biominerals in their trichomes. Thirty of the species had calcium phosphate in their trichomes. Loasa was mostly free of silica, but contained calcium phosphate in trichome tips and barbs, whereas calcium phosphate and silica were found in representatives of other genera of the family (Blumenbachia, Caiophora, Nasa). CONCLUSIONS Biomineralization is remarkably diversified between species, different trichome types and parts of the same trichome. Individual genera largely had different patterns of biomineralization. The presence of three biominerals in the trichomes of the basally branching Eucnide urens indicates either an early evolution and subsequent loss or several independent origins of multiple biomineralization. Differential biomineralization of the parts of individual, unicellular trichomes clearly indicates an extraordinary degree of physiological control over this process.
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A first report of hydroxylated apatite as structural biomineral in Loasaceae – plants’ teeth against herbivores
Scientific Reports, 2016Co-Authors: Hans-jürgen Ensikat, Thorsten Geisler, Maximilian WeigendAbstract:Biomineralization provides living organisms with various materials for the formation of resilient structures. Calcium phosphate is the main component of teeth and bones in vertebrates, whereas especially silica serves for the protection against herbivores on many plant surfaces. Functional calcium phosphate structures are well-known from the animal kingdom, but had not so far been reported from higher plants. Here, we document the occurrence of calcium phosphate biomineralization in the South-American plant group Loasaceae (rock nettle family), which have Stinging trichomes similar to those of the well-known Stinging nettles ( Urtica ). Stinging Hairs and the smaller, glochidiate trichomes contained nanocrystalline hydroxylated apatite, especially in their distal portions, replacing the silica found in analogous structures of other flowering plants. This could be demonstrated by chemical, spectroscopic and diffraction analyses. Some species of Loasaceae contained both calcium phosphate and silica in addition to calcium carbonate. The intriguing discovery of structural hydroxylated apatite in plants invites further studies, e.g., on its systematic distribution across the family, the genetic and cellular control of plant biomineralization, the properties and ultrastructure of calcium phosphate. It may prove the starting point for the development of biomimetic calcium phosphate composites based on a cellulose matrix.
Tracy L Kivell - One of the best experts on this subject based on the ideXlab platform.
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manual skills for food processing by mountain gorillas gorilla beringei beringei in bwindi impenetrable national park uganda
Biological Journal of The Linnean Society, 2019Co-Authors: Johanna Neufuss, Jana Baeumer, Tatyana Humle, Tracy L Kivell, Martha M RobbinsAbstract:Although gorillas rarely use tools in the wild, their manipulative skills during plant processing may be similar to those of other tool-using great apes. Virunga mountain gorillas are known for the complexity in their methods of thistle and nettle plant preparation in the wild. However, there has been no comparable data on food processing in the population of mountain gorillas from the Bwindi Impenetrable National Park, Uganda. We investigated the manual actions and hand grips used when accessing edible parts of two hard-to-process plants defended by Stinging Hairs, epidermis or periderm (i.e., peel of Urera hypselodendron and pith of Mimulopsis arborescens) and one undefended plant (i.e., leaves of Momordica foetida) in 11 Bwindi wild mountain gorillas (Gorilla beringei beringei) using video records ad libitum. Similar to thistle feeding by Virunga gorillas, Bwindi gorillas used the greatest number of manual actions for the most hard-to-process plant (U. hypselodendron), the actions were ordered in several key stages and organised hierarchically. The demands of processing plant material elicited 19 different grips and variable thumb postures, of which three grips were new and 16 grips have either been previously reported or show clear similarities to grips used by other wild and captive African apes and humans. Moreover, our study only partly supports a functional link between diet and hand morphology in mountain gorillas and suggests that the gorilla hand is best adapted to forceful grasping that is required for both manipulation and arboreal locomotion.
Ken Oyama - One of the best experts on this subject based on the ideXlab platform.
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Variation in leaf trichomes of Wigandia urens: environmental factors and physiological consequences.
Tree physiology, 2000Co-Authors: Leticia B. Pérez-estrada, Zenón Cano-santana, Ken OyamaAbstract:Seasonal and environmentally induced variation in the type and frequency of leaf trichomes of Wigandia urens (Ruiz & Pavon) Kunth (Hydrophyllaceae) was studied. Depending on the microsite, W. urens plants had smooth leaves with glandular trichomes or bristly leaves with both glandular trichomes and urticant trichomes (Stinging Hairs). Trichome density (number of urticant trichomes per unit leaf area) was higher in the dry season than in the wet season, and was significantly correlated with both temperature (r = 0.353, P < 0.05) and photosynthetic active radiation (r = 0.313, P < 0.05). Plants established in sun-exposed areas had trichome densities three times higher than those of plants established in shaded areas during the dry season, and 28 times higher during the wet season. At both exposed and shaded sites, trichome densities of the youngest leaves of young plants were higher than those of the youngest leaves of mature plants. In smooth and bristly leaves, transpiration rates decreased with increasing temperature during the day. However, smooth leaves had higher transpiration rates than bristly leaves at both exposed and shaded sites. In laboratory studies, trichome density was significantly (P < 0.01) reduced when small sun-grown plants (0.20-0.30 m tall) were either shaded or irrigated. In larger plants, also, irrigation significantly (P < 0.01) reduced trichome density relative to that of unirrigated controls.
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Variation in leaf trichomes and nutrients of Wigandia urens (Hydrophyllaceae) and its implications for herbivory
Oecologia, 1992Co-Authors: Zenón Cano-santana, Ken OyamaAbstract:Leaf trichome variation was studied in a population of Wigandia urens (Hydrophyllaceae) in relation to water availability, diversity of herbivorous insects, and grazing rates. Plants of W. urens have glandular and urticant (Stinging Hairs) trichomes, and it is possible to distinguish two types of leaves: “smooth” leaves with only glandular trichomes and “bristly” leaves with both types of trichomes. Density of urticant trichomes was negatively correlated with weekly mean precipitation. Fourteen species of insects in five different orders feed on leaves of W. urens throughout the year. Grazing rates varied according to type and age of leaves. Grazing rates were lower in smooth than bristly young leaves but the rates were similar for mature leaves. Secondary metabolites, screened using qualitative methods, showed similar classes of compounds in both types of leaves. Bristly leaves had significantly higher concentrations of nitrogen, phosphorous and water and these nutritional differences were well correlated with the differences in grazing rates between bristly and smooth leaves.
Hans-jürgen Ensikat - One of the best experts on this subject based on the ideXlab platform.
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Distribution, Ecology, Chemistry and Toxicology of Plant Stinging Hairs
Toxins, 2021Co-Authors: Hans-jürgen Ensikat, Hannah Wessely, Marianne Engeser, Maximilian WeigendAbstract:Plant Stinging Hairs have fascinated humans for time immemorial. True Stinging Hairs are highly specialized plant structures that are able to inject a physiologically active liquid into the skin and can be differentiated from irritant Hairs (causing mechanical damage only). Stinging Hairs can be classified into two basic types: Urtica-type Stinging Hairs with the classical "hypodermic syringe" mechanism expelling only liquid, and Tragia-type Stinging Hairs expelling a liquid together with a sharp crystal. In total, there are some 650 plant species with Stinging Hairs across five remotely related plant families (i.e., belonging to different plant orders). The family Urticaceae (order Rosales) includes a total of ca. 150 Stinging representatives, amongst them the well-known Stinging nettles (genus Urtica). There are also some 200 Stinging species in Loasaceae (order Cornales), ca. 250 Stinging species in Euphorbiaceae (order Malphigiales), a handful of species in Namaceae (order Boraginales), and one in Caricaceae (order Brassicales). Stinging Hairs are commonly found on most aerial parts of the plants, especially the stem and leaves, but sometimes also on flowers and fruits. The ecological role of Stinging Hairs in plants seems to be essentially defense against mammalian herbivores, while they appear to be essentially inefficient against invertebrate pests. Stinging plants are therefore frequent pasture weeds across different taxa and geographical zones. Stinging Hairs are usually combined with additional chemical and/or mechanical defenses in plants and are not a standalone mechanism. The physiological effects of Stinging Hairs on humans vary widely between Stinging plants and range from a slight itch, skin rash (urticaria), and oedema to sharp pain and even serious neurological disorders such as neuropathy. Numerous studies have attempted to elucidate the chemical basis of the physiological effects. Since the middle of the 20th century, neurotransmitters (acetylcholine, histamine, serotonin) have been repeatedly detected in Stinging Hairs of Urticaceae, but recent analyses of Loasaceae Stinging hair fluids revealed high variability in their composition and content of neurotransmitters. These substances can explain some of the physiological effects of Stinging Hairs, but fail to completely explain neuropathic effects, pointing to some yet unidentified neurotoxin. Inorganic ions (e.g., potassium) are detected in Stinging Hairs and could have synergistic effects. Very recently, ultrastable miniproteins dubbed "gympietides" have been reported from two species of Dendrocnide, arguably the most violently Stinging plant. Gympietides are shown to be highly neurotoxic, providing a convincing explanation for Dendrocnide toxicity. For the roughly 648 remaining Stinging plant species, similarly convincing data on toxicity are still lacking.
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Stinging hair morphology and wall biomineralization across five plant families: Conserved morphology versus divergent cell wall composition.
American journal of botany, 2018Co-Authors: Adeel Mustafa, Hans-jürgen Ensikat, Maximilian WeigendAbstract:Premise of the study Stinging Hairs are striking examples of plant microengineering-the plant equivalent of the hypodermic syringe. The requisite mechanical properties are mostly achieved by cell wall mineralization. Stinging Hairs of Urtica dioica (Urticaceae) are known to be mineralized with silica and calcium carbonate and those of Loasaceae also with calcium phosphate, but no comparative study has been provided across different taxa with Stinging Hairs. Methods Light microscopy and scanning electron microscopy (SEM) with cryo-SEM and energy-dispersive x-ray spectroscopy were used to analyze morphology and biomineralization of Stinging Hairs of 43 species from the families Caricaceae, Euphorbiaceae, Loasaceae, Namaceae, and Urticaceae. Key results Stinging hair morphology is similar across the taxa studied, in striking contrast to the divergent patterns of biomineralization. Trichome bases are mostly calcified, sometimes silicified, the shafts are mostly calcified, and the apices silicified (Urticaceae), and contain calcium phosphate (Caricaceae, Namaceae), both silica and calcium phosphate (some Loasaceae), or no minerals (Cnidoscolus, Euphorbiaceae). Some Stinging Hairs are superficially thinly coated with silica over a cell wall otherwise mineralized with calcium carbonate or calcium phosphate. Conclusions Mineralization patterns are surprisingly diverse and involve three different biominerals deposited in different parts of individual trichomes with calcium phosphate a common component. The physical properties of different wall regions of the Stinging trichomes are thus fine-tuned to optimize their function via modulation of wall thickness and differential element deposition. Similar function is apparently achieved through divergent wall compositions.
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Calcium phosphate in plant trichomes: the overlooked biomineral
Planta, 2017Co-Authors: Maximilian Weigend, Adeel Mustafa, Hans-jürgen EnsikatAbstract:Main conclusion Calcium phosphate was unknown as a plant biomineral until recently reported in Neotropical Loasaceae. Here, we demonstrate its widespread occurrence in the trichomes of several plant families, including Brassicaceae. Calcium phosphate is the primary biomineral in, e.g., the bones and teeth of higher animals; in plants, it was only recently discovered in the Stinging Hairs and scabrid–glochidiate trichomes of South American Loasaceae (Ensikat et al. in Sci Rep UK 6:26073, 2016), where it appears to be deposited highly specifically, often replacing the common plant biomineral silica. We initiated a broader survey in a range of different plant orders to investigate a possibly wider distribution of calcium phosphate biomineralization in plants. Scanning electron microscopy with EDX element analysis and mapping was used for the detection of the biominerals: calcium phosphate, calcium carbonate, and silica in the trichomes of several common plant species of different orders. Results were authenticated with Raman spectroscopy. Calcium phosphate was found in the trichomes of several species in the orders Malpighiales, Rosales, Boraginales, and Brassicales. It occurred in trichome tips, replacing the more common silica, or together with silica and calcium carbonate at specific locations in the trichome cell walls. Most surprisingly, it was found in the trichomes of Arabidopsis thaliana, one of the most studied plant species—where it had been overlooked so far. The wide distribution of calcium phosphate as plant biomineral here demonstrated and the striking mineralization patterns with three different biominerals in the walls of single-celled trichomes underscore an unexpected complexity in plant biomineralization.
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Complex patterns of multiple biomineralization in single‐celled plant trichomes of the Loasaceae
American journal of botany, 2017Co-Authors: Hans-jürgen Ensikat, Adeel Mustafa, Maximilian WeigendAbstract:PREMISE OF THE STUDY Plants of the family Loasaceae are characterized by a usually dense indument of various trichome types, including two basically different types of mineralized, unicellular trichomes (Stinging Hairs or setae and scabrid-glochidiate trichomes). Mineralized trichomes have long been known to have silicified or calcified walls, but recent studies demonstrated that trichomes of Loasaceae may also contain calcium phosphate. The current study investigates the distribution of different biominerals in the mineralized trichomes across several different taxa. METHODS Plants from cultivation were studied with scanning electron microscopy including energy dispersive x-ray analyses and element mapping. KEY RESULTS The vast majority of the 31 species investigated had at least two different biominerals in their trichomes, and 22 had three different biominerals in their trichomes. Thirty of the species had calcium phosphate in their trichomes. Loasa was mostly free of silica, but contained calcium phosphate in trichome tips and barbs, whereas calcium phosphate and silica were found in representatives of other genera of the family (Blumenbachia, Caiophora, Nasa). CONCLUSIONS Biomineralization is remarkably diversified between species, different trichome types and parts of the same trichome. Individual genera largely had different patterns of biomineralization. The presence of three biominerals in the trichomes of the basally branching Eucnide urens indicates either an early evolution and subsequent loss or several independent origins of multiple biomineralization. Differential biomineralization of the parts of individual, unicellular trichomes clearly indicates an extraordinary degree of physiological control over this process.
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A first report of hydroxylated apatite as structural biomineral in Loasaceae – plants’ teeth against herbivores
Scientific Reports, 2016Co-Authors: Hans-jürgen Ensikat, Thorsten Geisler, Maximilian WeigendAbstract:Biomineralization provides living organisms with various materials for the formation of resilient structures. Calcium phosphate is the main component of teeth and bones in vertebrates, whereas especially silica serves for the protection against herbivores on many plant surfaces. Functional calcium phosphate structures are well-known from the animal kingdom, but had not so far been reported from higher plants. Here, we document the occurrence of calcium phosphate biomineralization in the South-American plant group Loasaceae (rock nettle family), which have Stinging trichomes similar to those of the well-known Stinging nettles ( Urtica ). Stinging Hairs and the smaller, glochidiate trichomes contained nanocrystalline hydroxylated apatite, especially in their distal portions, replacing the silica found in analogous structures of other flowering plants. This could be demonstrated by chemical, spectroscopic and diffraction analyses. Some species of Loasaceae contained both calcium phosphate and silica in addition to calcium carbonate. The intriguing discovery of structural hydroxylated apatite in plants invites further studies, e.g., on its systematic distribution across the family, the genetic and cellular control of plant biomineralization, the properties and ultrastructure of calcium phosphate. It may prove the starting point for the development of biomimetic calcium phosphate composites based on a cellulose matrix.
Rongnan Huang - One of the best experts on this subject based on the ideXlab platform.
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identification of oxalic acid and tartaric acid as major persistent pain inducing toxins in the Stinging Hairs of the nettle urtica thunbergiana
Annals of Botany, 2006Co-Authors: Shiangjiuun Chen, Rueifeng Chen, Wang Hsien Ding, Linglong Kuohuang, Rongnan HuangAbstract:Background and Aims Once human skin contacts Stinging Hairs of Urtica spp. (Stinging nettles), the irritant is released and produces pain, wheals or a Stinging sensation which may last for >12h. However, the existence of pain-inducing toxins in the Stinging Hairs of Urtica thunbergiana has never been systematically demonstrated. Experiments were therefore conducted to identify the persistent pain-inducing agents in the Stinging Hairs of U. thunbergiana. Methods The Stinging Hairs of U. thunbergiana were removed and immersed in deionized water. After centrifugation, the clear supernatants were then subjected to high-performance liquid chromatography (HPLC), enzymatic analysis and/or behavioural bioassays. Key Results The HPLC results showed that the major constituents in the Stinging Hairs of U. thunbergiana were histamine, oxalic acid and tartaric acid. However, the well-recognized pain-inducing agents, serotonin and formic acid, existed at a low concentration as estimated by HPLC and/or enzymatic analyses. The behavioural tests showed that 2% oxalic acid and 10% tartaric acid dramatically elicited persistent pain sensations in rats. In contrast, 10% formic acid and 2% serotonin only elicited moderate pain sensation in the first 10min. Moreover, no significant pain-related behavioural response was observed after injecting 10% acetylcholine and histamine in rats. Conclusions Oxalic acid and tartaric acid were identified, for the first time, as major long-lasting pain-inducing toxins in the Stinging Hairs of U. thunbergiana. The general view that formic acid, histamine and serotonin are the pain-inducing agents in the Stinging Hairs of U. dioica may require updating, since their concentrations in U. thunbergiana were too low to induce significant pain sensation in behavioural bioassays.