RESUMEN
BACKGROUND: Jasmonic acid (JA) is a phytohormone involved in regulating responses to biotic and abiotic stress. Although the JA pathway is well characterized in model plants such as Arabidopsis thaliana, less is known about many non-model plants. Phytolacca americana (pokeweed) is native to eastern North Americana and is resilient to environmental stress. The goal of this study was to produce a publicly available pokeweed genome assembly and annotations and use this resource to determine how early response to JA changes gene expression, with particular focus on genes involved in defense. RESULTS: We assembled the pokeweed genome de novo from approximately 30 Gb of PacBio Hifi long reads and achieved an NG50 of ~ 13.2 Mb and a minimum 93.9% complete BUSCO score for gene annotations. With this reference, we investigated the early changes in pokeweed gene expression following JA treatment. Approximately 5,100 genes were differentially expressed during the 0-6 h time course with almost equal number of genes with increased and decreased transcript levels. Cluster and gene ontology analyses indicated the downregulation of genes associated with photosynthesis and upregulation of genes involved in hormone signaling and defense. We identified orthologues of key transcription factors and constructed the first JA gene response network integrated with our transcriptomic data from orthologues of Arabidopsis genes. We discovered that pokeweed did not use leaf senescence as a means of reallocating resources during stress; rather, most secondary metabolite synthesis genes were constitutively expressed, suggesting that pokeweed directs its resources for survival over the long term. In addition, pokeweed synthesizes several RNA N-glycosylases hypothesized to function in defense, each with unique expression profiles in response to JA. CONCLUSIONS: Our investigation of the early response of pokeweed to JA illustrates patterns of gene expression involved in defence and stress tolerance. Pokeweed provides insight into the defense mechanisms of plants beyond those observed in research models and crops, and further study may yield novel approaches to improving the resilience of plants to environmental changes. Our assembled pokeweed genome is the first within the taxonomic family Phytolaccaceae to be publicly available for continued research.
Asunto(s)
Ciclopentanos , Regulación de la Expresión Génica de las Plantas , Genoma de Planta , Oxilipinas , Reguladores del Crecimiento de las Plantas , Oxilipinas/farmacología , Oxilipinas/metabolismo , Ciclopentanos/metabolismo , Ciclopentanos/farmacología , Reguladores del Crecimiento de las Plantas/metabolismo , Reguladores del Crecimiento de las Plantas/farmacología , Phytolacca americana/genética , Phytolacca americana/metabolismoRESUMEN
In response to varying environments along urban and rural gradients, invasive plants may strategically allocate resources to enhance their invasiveness. However, how invasive plants balance their resources for growth, reproduction, and defense as responses to biotic and abiotic factors across these gradients remain unclear. We conducted field surveys on the growth, reproduction, and herbivory of the invasive species Phytolacca americana across diverse urban and rural habitats. Leaf samples were collected to analyze the nutritional content, primary and secondary metabolites. We found that plant growth rates, specific leaf area, leaf nitrogen content, and concentrations of flavonoids and saponins were higher in urban habitats, while reproduction, herbivory, and carbon-tonitrogen ratios were lower than those in rural habitats. We also found a trade-off between growth rate and herbivory, as well as trade-offs among defense traits associated with herbivory (e.g., leaf mass per area, the inverse of leaf nitrogen content, and carbonnitrogen ratio) and the production of metabolites associated with abiotic stress tolerance (e.g., soluble sugars, flavonoids, and saponins). As earlier studies showed low levels of genetic diversity within and between populations, our findings suggest that the urban-rural gradient patterns of resource allocation are primarily phenotypic plasticity in response to herbivory in rural areas and abiotic factors in urban areas. Our study sheds light on the mechanisms by which urbanization affects plant invasions and offers insights for the implementation of their management strategies.
Asunto(s)
Ecosistema , Especies Introducidas , Phytolacca americana , Reproducción , Herbivoria , Hojas de la Planta/metabolismoRESUMEN
The increased usage of rare earth elements (REEs) leads to the extensive exploitation of rare earth mines, and the REEs pollution in soil caused by the legacy mine tailings has brought great harm to environment and human health. Although Phytolacca americana can remove REEs from contaminated soil to some extent, there is still an urgent problem to improve its efficiency. Hyperaccumulator extract is a new organic material with potential in metal phytoextraction, but its role in REEs phytoremediation and the related underlying processes remain unclear. In this study, hyperaccumulator extracts from P. americana root (PR), stem (PS), leaf (PL) and EDTA were used to improve the phytoremediation efficiency of REEs with P. americana. Soil zymography was applied to assess the enzyme hotspots' spatial distribution in the rhizosphere, and the hotspots' microbial communities were also identified. The results indicated that the application of hyperaccumulator extracts improved the biomass and REEs uptake of P. americana, and the highest REEs content in plant was observed in the treatment of PS, which increased 299% compared to that of the control. Hotspots area of ß-glucosidase, leucine aminopeptidase and acid phosphatase were concentrated in the pant rhizosphere along the roots and increased 2.2, 5.3 and 2.2 times after PS application compared to unamended soils. The PS application increased the relative abundance of Proteobacteria, Cyanobacteria, Bacteroidota and Firmicutes phyla in rhizosphere. Soil fungi have a higher contribution on promoting REEs activation than that of bacteria. Available P and extractable REEs were leading predictors for the plant biomass and REEs concentrations. The co-occurrence network showed that the application of PS creates a more efficient and stable microbial network compared to other treatments. In conclusion, stem-derived hyperaccumulator extract is excellent in stimulating REEs phytoremediation with P. americana by improving hotspots microbial activities and form a healthy rhizosphere microenvironment.
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Biodegradación Ambiental , Metales de Tierras Raras , Phytolacca americana , Rizosfera , Microbiología del Suelo , Contaminantes del Suelo , Metales de Tierras Raras/metabolismo , Contaminantes del Suelo/metabolismo , Phytolacca americana/metabolismo , Microbiota , Raíces de Plantas/microbiología , Raíces de Plantas/metabolismoRESUMEN
Rare earth elements (REEs) are considered to be emerging contaminants due to their widespread use and lack of recycling. Phytolacca americana L. has great potential for REEs phytoextraction. Our understanding of REEs in P. americana focuses mostly on root absorption and xylem translocation, but the role of phloem translocation has received little attention. In this research, the translocation and fractionation of REEs from phloem to organs in P. americana were investigated. In addition, the effect of organic acids in the REEs translocation via phloem exudates was also examined. The results showed that REEs could transport bidirectionally via the phloem, and 86% of REEs exported from old leaves could move downwards to the root, whereas only 14% of them transported upwards to the young leaves. Heavy rare earth elements (HREEs) enrichment was found in the REEs fractionation processes both from phloem to leaf and from stem to root, indicating that HREEs were preferentially transferred not only down to roots, but also up to the young leaves. The concentration of oxalic acid in phloem exudates was much higher than other organic acids. 94.7% oxalic acid in phloem exudates was preferred to combine with REEs, especially HREEs. Additionally, the concentrations of HREEs had a high positive correlation with oxalic acid in phloem exudates, which demonstrated oxalic acid may play a significant role in the long-distance transport of HREEs in phloem. In conclusion, HREEs have higher translocation ability than light rare earth elements (LREEs) in both xylem and phloem of P. americana. As far as we know, this is the first report focused on the phloem translocation and redistribution of REEs in P. americana, which provides a valuable understanding of the mechanism for phytoremediation of REEs contaminated soils.
Asunto(s)
Metales de Tierras Raras , Phytolacca americana , Contaminantes del Suelo , Floema/química , Suelo , Agricultura , Metales de Tierras Raras/análisis , Contaminantes del Suelo/análisis , Compuestos Orgánicos , Ácidos , OxalatosRESUMEN
Food packaging films were prepared by using guar gum/polyvinyl alcohol (GP) as the film matrix, 2% Ag nanoparticles (AgNPs) as reinforcing filler and antimicrobial agent, and 1%, 2% and 3% pokeweed betacyanins (PB) as the colorant and antioxidant agent. The structures and color-changing, barrier, mechanical, thermal and antioxidant/antibacterial properties of different films were measured. The results show that the PB were pH-sensitive pigments with pink, purple and yellow colors at pH 3-8, pH 9-11 and pH 12, respectively. PB improved the compatibility of guar gum and polyvinyl alcohol through hydrogen bonds. The films with PB showed a color-changing capacity under ammonia vapor and good color stability in chilled storage. AgNPs and PB elevated the barrier capacity of GP film to light, water vapor and oxygen gas. Meanwhile, AgNPs and PB improved the stiffness, thermal stability and antioxidant/antibacterial activity of GP film. The film with AgNPs and 3% PB showed the highest barrier capacity, stiffness, thermal stability and antioxidant/antimicrobial activity. In shrimp spoilage test, the films with AgNPs and 2% and 3% PB indicated shrimp freshness through film color changes. The results reveal the potential use of the prepared films in active and smart packaging.
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Antígenos de Grupos Sanguíneos , Nanopartículas del Metal , Phytolacca americana , Phytolacca , Betacianinas , Alcohol Polivinílico , Plata , Embalaje de Alimentos , Frutas , Antioxidantes/farmacología , Antígenos Fúngicos , Antibacterianos/farmacologíaRESUMEN
Research on the invasive plant Phytolacca americana (L.) mostly focuses on its medicinal value and enrichment of heavy metals. However, little is known regarding its impact on native herbivorous insects. In this study, we explored the effects of P. americana and the exotic noninvasive Phytolacca icosandra (L.) on the Spodoptera litura (Fabricius) (native tobacco cutworm) via bioassay, oviposition preference, detoxifying enzyme activity analysis, and phytochemical determination. We found that the oviposition preference index (OPI) of S. litura feeding on P. icosandra was higher than that of P. americana. The developmental duration of S. litura feeding on P. icosandra was shorter than that of P. americana. Additionally, the Acetylcholinesterase (AchE) and Glutathione-S-transferase (GST) activities of S. litura feeding on P. americana were higher than that of S. litura feeding on artificial diets or P. icosandra. The content of lignin and flavonoids in P. americana was relatively high, whereas starch content was relatively low. These findings suggest invasive plants have higher resistance to herbivores, thereby suffering less damage than exotic noninvasive plants.
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Acetilcolinesterasa , Herbivoria , Phytolacca , Spodoptera , Animales , Femenino , Acetilcolinesterasa/farmacología , Larva , Spodoptera/fisiología , Phytolacca americanaRESUMEN
Phytolacca americana is a Cd hyperaccumulator plant that accumulates significant amounts of Cd in leaves, making it a valuable phytoremediation plant species. Our previous research found enolase (ENO) may play an important part in P. americana to cope with Cd stress. As a multifunctional enzyme, ENO was involved not only in glycolysis but also in the response of plants to various environmental stresses. However, there are few studies on the function of PaENO (P. americana enolase) in coping with Cd stress. In this study, the PaENO gene was isolated from P. americana, and the expression level of PaENO gene significantly increased after Cd treatment. The enzymatic activity analysis showed PaENO had typical ENO activity, and the 42-position serine was essential to the enzymatic activity of PaENO. The Cd resistance assay indicated the expression of PaENO remarkably enhanced the resistance of E. coli to Cd, which was achieved by reducing the Cd content in E. coli. Moreover, both the expression of inactive PaENO and PaMBP-1 (alternative translation product of PaENO) can improve the tolerance of E. coli to Cd. The results indicated PaENO may be alternatively translated into the transcription factor PaMBP-1 to participate in the response of P. americana to Cd stress.
The expression of the Cd resistance related protein PaENO can significantly increase the tolerance of E. coli to Cd, which was achieved by reducing the content of Cd in E. coli cells, and was independent of the enzymatic activity of PaENO. Moreover, PaENO may be alternatively translated into the transcription factor PaMBP-1 to participate in the response of P. americana to Cd stress.
Asunto(s)
Cadmio , Phytolacca americana , Cadmio/metabolismo , Phytolacca americana/genética , Phytolacca americana/metabolismo , Escherichia coli/metabolismo , Fosfopiruvato Hidratasa/metabolismo , Biodegradación Ambiental , Raíces de Plantas/químicaRESUMEN
Phytolacca americana, known more commonly as "pokeweed", is a large perennial plant found ubiquitously throughout the United States. Despite known toxicities, characterization of pokeweed exposure demographics, symptoms, treatments, and outcomes is currently limited. The objective of this study is to describe human pokeweed exposures, treatments, and outcomes, in the state of Kentucky, between 2000 and 2019. The National Poison Database System was queried for all Phytolacca americana exposures in the state of Kentucky between 2000 and 2019. After the removal of non-human cases, investigators independently reviewed data to ensure all coding was appropriate per the standards set forth by NPDS. The primary objective of this study was to describe pokeweed exposure demographics within the state of Kentucky during the previously established timeframe. Secondary objectives included characterizing pokeweed treatment trends and evaluating their affiliated medical outcomes. 1669 cases of human pokeweed exposure were reported. Patients were predominantly young in age, with a median age of 3 years reported. The majority of patients were male (54.9%), with unintentional exposures representing most exposure reasons (97.2%). Oral ingestion of plant material represented the bulk of the exposure route (98.3%), with pokeberries most often implicated in these cases (93.9%). Exposures were generally well tolerated. 239 total adverse events were noted during the timeframe. Abdominal pain, nausea, vomiting, and diarrhea were most common. Dermal exposures resulted in cutaneous edema, pain, and swelling. Treatments were mainly supportive, with no deaths reported during the study timeframe. In conclusion, Phytolacca americana is commonly encountered in the United States. In this observational study, patients most heavily implicated in pokeweed exposures are young males. Oral ingestion was most commonly reported, with berries most often implicated. Exposures are generally well tolerated, with gastrointestinal symptoms most frequently reported. Cutaneous exposures represent an underappreciated exposure route. Treatments are largely supportive in nature.
Asunto(s)
Phytolacca americana , Masculino , Humanos , Estados Unidos , Femenino , Kentucky/epidemiología , Plantas , Vómitos , Frutas , Centros de Control de IntoxicacionesRESUMEN
Phytoremediation is an effective way to remove metals from contaminated soil, and selecting remediation plants suitable for climate conditions is a prerequisite for effective phytoremediation. In this study, a MaxEnt model was applied to investigate the potential distribution and habitat suitability of three Cd-accumulating plants in China- Sedum alfredii, Phytolacca americana, and Hylotelephium spectabile and explore the key environmental factors that affect their habitat suitability. A total of 44 environmental parameters, including bioclimatic variables, altitude, and soil property parameters were used. The results showed that: (1) For S. alfredii, suitable areas account for 14.9 % of the area of China, which are mainly distributed in the middle and lower reaches of the Yangtze River. (2) The suitable areas of P. americana account for 22.7 % of China and are mainly located in the regions of the Qinling Mountains and the south of China. (3) While that for H. spectabile are mainly located in the regions of northeastern China and certain regions of central China, with suitable areas account for 8.3 % of the area of China. (4) The distribution of these three plants is significantly affected by precipitation; specifically, solar radiation is an influential factor for the distribution of S. alfredii and H. spectabile, and temperature limits the distribution of P. americana. The selection and agronomic management of hyperaccumulators for phytoremediation requires multifactor consideration (e.g., climate, soil conditions and planting patterns). The results can provide guidance for identifying suitable areas for planting these three accumulating plants, which could not only prevent the unscientific cultivation of them in unsuitable habitats but also enhance the efficiency of phytoremediation. Meanwhile, these findings are expected to contribute to agronomic management for improved phytoremediation effects in different Cd-contaminated regions of China.
Asunto(s)
Phytolacca americana , Sedum , Contaminantes del Suelo , Cadmio/análisis , Contaminantes del Suelo/análisis , Biodegradación Ambiental , SueloRESUMEN
Phytoremediation is a potentially cost-effective and environmentally friendly remediation method for environmental pollution. However, the safe treatment and resource utilization of harvested biomass has become a limitation in practical applications. To address this, a novel manganese-carbon-based single-atom catalyst (SAC) method has been developed based on the pyrolysis of a manganese hyperaccumulator, Phytolacca americana. In this method, manganese atoms are dispersed atomically in the carbon matrix and coordinate with N atoms to form a Mn-N4 structure. The SAC developed exhibited a high photooxidation efficiency and excellent stability during the degradation of a common organic pollutant, rhodamine B. The Mn-N4 site was the active center in the transformation of photoelectrons via the transfer of photoelectrons between adsorbed O2 and Mn to produce reactive oxygen species, identified by in situ X-ray absorption fine structure spectroscopy and density functional theory calculations. This work demonstrates an approach that increases potential utilization of biomass during phytoremediation and provides a promising design strategy to synthesize cost-effective SACs for environmental applications.
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Restauración y Remediación Ambiental , Phytolacca americana , Carbono/metabolismo , Carbón Orgánico , Manganeso/química , Phytolacca americana/metabolismoRESUMEN
Capsaicinoids are phenolic compounds that have health benefits. However, the pungency and poor water solubility of these compounds limit their exploitation. Glycosylation is a powerful method to improve water solubility and reduce pungency while preserving bioactivity. PaGT3, a uridine diphosphate glycosyltransferase (UGT) from Phytolacca americana, is known for its ability to glycosylate capsaicinoids and other phenolic compounds. While structural information on several UGTs is available, structures of UGTs that can glycosylate a range of phenolic compounds are rare. To fill this gap, crystal structures of PaGT3 with a sugar-donor analogue (UDP-2-fluoroglucose) and the acceptors capsaicin and kaempferol were determined. PaGT3 adopts a GT-B-fold structure that is highly conserved among UGTs. However, the acceptor-binding pocket in PaGT3 is hydrophobic and large, and is surrounded by longer loops. The larger acceptor-binding pocket in PaGT3 allows the enzyme to bind a range of compounds, while the flexibility of the longer loops possibly plays a role in accommodating the acceptors in the binding pocket according to their shape and size. This structural information provides insights into the acceptor-binding mechanism in UGTs that bind multiple substrates.
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Glicosiltransferasas , Phytolacca americana , Glicosilación , Glicosiltransferasas/química , Uridina Difosfato/química , Uridina Difosfato/metabolismoRESUMEN
BACKGROUND: Pokeweed (Phytolacca americana L.) is regarded as an invasive plant in many parts of the world but possesses therapeutic characteristics used for antitumor and rheumatism treatment. This study investigated the effects of auxins and four explants on pokeweed callus induction. The effects of cytokinins and combinations between cytokinins and NAA on shoot and root induction were also studied. TPC, TFC and antioxidant activity of calli were screened and compared with other pokeweed plant parts. METHODS: Four explants were used to induce callus using 2,4-D and IBA at 1, 2, 3 and 4 mg/l for each auxin. Direct shoot organogenesis from nodal explants was investigated using BAP, kinetin and TDZ (1, 2 and 4 mg/l for each cytokinin). Combined effects between cytokinins and NAA at 0.1, 0.2 and 0.3 mg/l were further simultaneously estimated with root induction. Calli derived from the leaves were compared with other plant parts for TPC, TFC and antioxidant activity using the Folin-Ciocalteu, AlCl3 colorimetric assay and DPPH assays, respectively. RESULTS: Results showed that MS medium containing 2 mg/l 2,4-D induced callus formation on leaf explants that provided highest fresh and dry weights. Three types of synthetic cytokinins as kinetin, TDZ and BAP were used for direct shoot organogenesis from pokeweed nodes. MS medium containing 2 mg/l kinetin was effective in stimulating normal shoots, with the largest number of shoots and leaves and the longest shoots. The combination between cytokinins and NAA showed no positive effect on shoot and root induction from pokeweed nodal explants. For TPC and TFC determination, pokeweed seeds and leaves possessed the highest phenolic and flavonoid contents, respectively. Highest phenolic content of pokeweed seeds led to lowest IC50 by DPPH assay. Phenolic content was higher than flavonoid content. CONCLUSION: Results suggested promising conditions for callus induction. Leaf explants cultured on MS medium with 2 mg/l 2,4-D and nodal explants cultured on MS medium with 2 mg/l kinetin provided the largest number of normal shoots and leaves. NAA did not show positive effects on shoot and root induction when combined with cytokinins. Chemical constituent screening indicated that seeds and leaves provided highest TPC and TFC, respectively, while pokeweed calli contained higher phenolic than flavonoid content. This is the first report describing chemical constituent screening and antioxidant activity of calli and other parts of the pokeweed plant. Results provided significant information to further enhance bioactive compound contents of pokeweed calli using elicitation methods.
Asunto(s)
Antioxidantes , Phytolacca americana , Antioxidantes/farmacología , Brotes de la Planta , Cinetina/farmacología , Citocininas/farmacología , Plantas , Ácidos Indolacéticos/farmacología , Ácido 2,4-Diclorofenoxiacético/farmacologíaRESUMEN
Organic acids play an important role in metal tolerance, uptake, and translocation in hyperaccumulators. Phytolacca americana is a rare earth element (REE) hyperaccumulator, but the underlying mechanisms on REE tolerance and accumulation mediated by organic acids are poorly understood. Here, we reported for the first time the strategy of P. americana to enhance REE tolerance and accumulation through organic acids from root external secretion to internal biosynthesis. Different from the exclusion of heavy metal by organic acid in the typical plants, the results showed that oxalate secretion (0.3-0.6 µmol h-1 g-1 root DW) induced by yttrium (Y) could not prevent Y from entering the roots, resulting in excess Y uptake by P. americana. Yttrium stress also stimulated the accumulation of malate and citrate by 1.4- and 2.0-folds in the root cortex. Exogenous malate and citrate promoted the redistribution of Y from the root cell walls to the shoot by 30% and 21%, respectively. Based on comparative transcriptome analysis, 6-fold up-regulation was observed in PaNIP1;2, whose homology AtNIP1;2 is responsible for the transport of Al-malate in Arabidopsis. These results suggested that the promoted formation of Y-malate complexes within the roots potentially accelerated the transport of Y from P. americana roots to shoots through PaNIP1;2. Our study revealed the potential mechanism of organic acids in the external exclusion and internal detoxification and translocation of REE in P. americana roots, which provided a basis for improving the efficiency of REE phytoextraction.
Asunto(s)
Arabidopsis , Metales de Tierras Raras , Phytolacca americana , Compuestos Orgánicos , Raíces de PlantasRESUMEN
Engineered biochar represents a promising material for green remediation practices. In this paper, we present an innovative approach to produce MnOx-loaded biochars by pyrolyzing the biomass of a Mn-hyperaccumulator species (Phytolacca americana). Batch sorption and stirred-flow kinetic experiments were combined with spectroscopic techniques to elucidate the mechanisms behind the Cd sorption onto those biochars, named here as PABCs. The incorporation of MnOx into the PABCs increased their surface densities of oxygen-containing functional groups. The average Mn leaching (< 9%) from PABCs was lower than that measured for the non-pyrolyzed biomass of P. americana (30-43%). PABCs pyrolyzed at 500 °C had Cd sorption capacities as high as 212-337 mg/g, which achieved by far the best performance reported for biochar materials. The stirred-flow experiments showed that MnOx loading was instrumental in increasing both the Cd sorption onto PABCs as well as its irreversibility. Extended X-ray absorption fine structure spectroscopy revealed that the Cd immobilization occurred mainly through its association with organic matter (Cd-OM) and, to a lesser extent, with carbonate (CdCO3) and MnOx (Cd-MnOx). In short, MnOx-loaded biochar prepared from the biomass of a Mn-hyperaccumulator species proved to be an effective, sustainable, and eco-friendly material for remediating Cd-contaminated waters.
Asunto(s)
Phytolacca americana , Adsorción , Cadmio , Carbón OrgánicoRESUMEN
In recent years, nano-contamination in the soil environment has aroused concern. But it is still uncertain whether the interactions of nano- and metal-pollutants would have a combined toxic effect on plants. In this study, we investigated the effects of joint exposure to zinc oxide nanoparticles (ZnO NPs) and Cd on the root tissue of Phytolacca americana L. Spin-polarized density functional theory simulations assumed that the plant may undergo metal toxicity or acidosis upon joint exposure to ZnO NPs/Cd. Subsequently, experimental exposure of P. americana verified the combined toxic effects. The plant grew normally with a single treatment of ZnO NPs (500 mg/kg) or low doses of Cd (10 mg/kg). However, root growth was significantly inhibited with the combined treatments (up to 43% reduction); additionally, Cd ions were transported to the shoot, leading to shoot growth inhibition (translocation factor > 1). The antioxidant enzymes in the root (superoxide dismutase, peroxidase, and catalase) were highly activated to resist stress, accompanied by a greater than two-fold increase in thiobarbituric acid reactive substances. Corresponding to physiological indicators, biological transmission electron microscopy revealed severe damage to the root cells. Moreover, ZnO NPs/Cd accumulation was observed in the root cytoderm, which confirmed the toxicity of the combined effects. Our study provides insight into the potential combined toxicity of ZnO NPs and heavy metals in polluted environments, such as mining areas and electronic waste sites, and agricultural soils.
Asunto(s)
Nanopartículas del Metal , Nanopartículas , Phytolacca americana , Contaminantes del Suelo , Óxido de Zinc , Cadmio/toxicidad , Nanopartículas del Metal/toxicidad , Nanopartículas/toxicidad , Raíces de Plantas , Contaminantes del Suelo/toxicidad , Óxido de Zinc/toxicidadRESUMEN
The plant Phytolacca americana L. simultaneously hyperaccumulates manganese (Mn) and rare earth elements (REEs), but the underlying mechanisms are largely unknown. In this study, P. americana and the corresponding rhizosphere soil samples were collected from an ion-adsorption REE mine area in China, and the elemental composition and soil properties were analyzed in order to explore the relationship between metal accumulation and soil properties. The results show that P. americana accumulates high concentrations of REEs (up to 1040 mg kg-1), Mn (up to 10400 mg kg-1) and aluminum (Al) (up to 5960 mg kg-1) in leaves. The REE concentrations in leaves were positively correlated with those of Al, Fe and Zn, while light REE concentrations were negatively correlated with P concentrations (p < 0.05). The soil properties explained 81.7%, 72.9% and 67.1% of REEs, Mn and Al accumulated in P. americana, respectively. The variation of REE accumulation in P. americana was primarily explained by plant available P (24.4%), pH (12.9%), TOC (9.4%) and total P (7.7%). The accumulation of Mn was primarily explained by plant available REEs (42.9%) and available Al (13.1%) while Al in P. americana was primarily explained by soil pH (14.4%). This study suggests the potential by regulation of soil properties in improving the efficiency of phytoextraction for REEs by hyperaccumulators.
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Metales de Tierras Raras , Phytolacca americana , Contaminantes del Suelo , Aluminio , Biodegradación Ambiental , Manganeso , Raíces de Plantas , SueloRESUMEN
The biotransformations of capsaicin and dihydrocapsaicin were investigated using cultured plant cells of Phytolacca americana as biocatalysts. Four products, ie 15-hydroxycapsaicin, dihydrocapsaicin, 15-hydroxydihydrocapsaicin, and capsaicin 4-ß-glucoside, were isolated from the suspension cultures of P. americana treated with capsaicin for 3 days, showing that capsaicin was regioselectively hydroxylated, reduced, and glucosylated by cultured P. americana cells. On the other hand, dihydrocapsaicin was regioselectively dehydrogenated, hydroxylated, reduced, and glucosylated to give four products, ie capsaicin, 15-hydroxycapsaicin, 15-hydroxydihydrocapsaicin, and capsaicin 4-ß-glucoside, by cultured P. americana cells. In this paper, it is reported, for the first time, that dihydrocapsaicin is converted into 15-hydroxydihydrocapsaicin by plant cultured cells.
Asunto(s)
Capsaicina/química , Capsaicina/metabolismo , Phytolacca americana/metabolismo , Biotransformación , Hidrogenación , Hidroxilación , Phytolacca americana/citología , Phytolacca americana/crecimiento & desarrollo , EstereoisomerismoRESUMEN
Diverse arrays of naturally occurring compounds in plants are synthesized by specialized metabolic enzymes, many of which are distributed taxonomically. Although anthocyanin pigments are widely distributed and ubiquitous, betalains have replaced anthocyanins in most families in Caryophyllales. Anthocyanins and betalains never occur together in the same plant. The formation of betalamic acid, catalyzed by 3,4-dihydroxyphenylalanine (DOPA) 4,5-extradiol dioxygenase (DOD), is a key step in betalain biosynthesis. DODs in betalain-producing plants are coded by LigB genes, homologs of which have been identified in a wide range of higher plant orders, as well as in certain fungi and bacteria. Two classes of LigB homologs have been reported: those found in anthocyanin-producing species and those found in betalain-producing species, which contain DOD. To gain insight into the evolution of specialized metabolic enzymes involved in betalain biosynthesis, we performed a comparative biochemical analysis of Arabidopsis LigB, an extradiol ring-cleavage dioxygenase in anthocyanin-producing Arabidopsis and Phytolacca DOD1 of betalain-producing Phytolacca americana. We show that Arabidopsis LigB catalyzes 2,3-extradiol cleavage of DOPA to synthesize muscaflavin, whereas Phytolacca DOD1 converts DOPA to betalamic acid via 4,5-extradiol cleavage. Arabidopsis LigB also converts caffeic acid, a ubiquitous phenolic compound in higher plants, to iso-arabidopic acid in vitro via 2,3-extradiol cleavage of the aromatic ring. Amino-acid substitution in Arabidopsis LigB and Phytolacca DOD1 led to variable extradiol ring-cleavage function, supporting the suggestion that catalytic promiscuity serves as a starting point for the divergence of new enzymatic activities.
Asunto(s)
Proteínas de Arabidopsis/metabolismo , Betalaínas/metabolismo , Dioxigenasas/metabolismo , Phytolacca americana/enzimología , Proteínas de Plantas/metabolismo , Sustitución de Aminoácidos , Proteínas de Arabidopsis/química , Dihidroxifenilalanina/metabolismo , Dioxigenasas/química , Proteínas de Plantas/química , Piridinas/metabolismoRESUMEN
CONTEXT: With the rise of antibiotic resistance, new strategies are needed to treat minor bacterial infections so that conventional antibiotics may be reserved for more serious conditions. One herbal formula, known as the HMPE formula, is often prescribed for minor infections. It includes Hydrastis canadensis (H. canadensis), Commiphora habessinica (C. habessinica), Phytolacca americana (P. americana), and Echinacea purpurea (E. purpurea). These herbs offer promise as treatments that may inhibit bacterial growth and stimulate the immune system. OBJECTIVE: To investigate the antibacterial effects of the HMPE formula and its constituent herbs against two organisms, Staphylococcus epidermidis and Escherichia coli. DESIGN: The research team performed an in-vitro study. SETTING: The study occurred at the Helfgott Research Institute at the National University of Natural Medicine in Portland, OR, USA. INTERVENTION: The study tested HMPE and each of its ingredients alone for antibacterial properties. OUTCOME MEASURES: The outcome measure was a disc diffusion assay. Sterile paper discs were impregnated with 15 µl of E. purpurea, H. canadensis, C. habessinica , or P. americana as herbal tinctures; with the complete HMPE formula; or with 65% ethanol as the negative control, and dried at room temperature for 40 minutes. Commercially prepared 10 µg ampicillin discs were used as a positive control. RESULTS: H. Canadensis and, to a lesser extent, the complete HMPE formula significantly inhibited the growth of the gram-positive bacteria Staphylococcus epidermidis, but not the gram-negative bacteria Escherichia coli. C. habessinica, P. americana, and E. purpurea alone did not inhibit growth of either bacterial strain. CONCLUSIONS: The results demonstrated that H. canadensis had antibacterial activity against S. epidermidis, but the HMPE formula was not active against S. epidermidis, when a zone of inhibition threshold of 12 millimeters (mm) was used to determine antibiotic activity. Because the HMPE formula was shown to be less effective than H. canadensis alone, the formula might benefit from an increased percentage of H. canadensis.
Asunto(s)
Echinacea , Hydrastis , Phytolacca americana , Antibacterianos/farmacología , Commiphora , Humanos , Extractos Vegetales/farmacologíaRESUMEN
The potential of plant extracts as bioinsecticides has been described as a promising field of agricultural development. In this work, the extracts of Punica granatum (pomegranate), Phytolacca americana (American pokeweed), Glandora prostrata (shrubby gromwell), Ulex europaeus (gorce), Tagetes patula (French marigold), Camellia japonica red (camellia), Ruta graveolens (rue or herb-of-grace) were obtained, purified, and their activity against Spodoptera frugiperda (Sf9) insect cells was investigated. From the pool of over twenty extracts obtained, comprising different polarities and vegetable materials, less polar samples were shown to be more toxic towards the insect cell line Sf9. Among these, a dichloromethane extract of R. graveolens was capable of causing a loss of viability of over 50%, exceeding the effect of the commercial insecticide chlorpyrifos. This extract elicited chromatin condensation and the fragmentation in treated cells. Nanoencapsulation assays of the cytotoxic plant extracts in soybean liposomes and chitosan nanostructures were carried out. The nanosystems exhibited sizes lower or around 200 nm, low polydispersity, and generally high encapsulation efficiencies. Release assays showed that chitosan nanoemulsions provide a fast and total extract release, while liposome-based systems are suitable for a more delayed release. These results represent a proof-of-concept for the future development of bioinsecticide nanoformulations based on the cytotoxic plant extracts.