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Addressing the global challenge of bacterial resistance demands innovative approaches, among which multitargeting is a widely used strategy. Current strategies of multitargeting, typically achieved through drug combinations or single agents inherently aiming at multiple targets, face challenges such as stringent pharmacokinetic and pharmacodynamic requirements and cytotoxicity concerns. In this report, we propose a bacterial-specific global disruption approach as a vastly expanded multitargeting strategy that effectively disrupts bacterial subcellular organization. This effect is achieved through a pioneering chemical design of ligand-receptor interaction-induced aggregation of small molecules, i.e., DNA-induced aggregation of a diarginine peptidomimetic within bacterial cells. These intracellular aggregates display affinity toward various proteins and thus substantially interfere with essential bacterial functions and rupture bacterial cell membranes in an "inside-out" manner, leading to robust antibacterial activities and suppression of drug resistance. Additionally, biochemical analysis of macromolecule binding affinity, cytoplasmic localization patterns, and bacterial stress responses suggests that this bacterial-specific intracellular aggregation mechanism is fundamentally different from nonselective classic DNA or membrane binding mechanisms. These mechanistic distinctions, along with the peptidomimetic's selective permeation of bacterial membranes, contribute to its favorable biocompatibility and pharmacokinetic properties, enabling its in vivo antimicrobial efficacy in several animal models, including mice-based superficial wound models, subcutaneous abscess models, and septicemia infection models. These results highlight the great promise of ligand-receptor interaction-induced intracellular aggregation in achieving a globally disruptive multitargeting effect, thereby offering potential applications in the treatment of malignant cells, including pathogens, tumor cells, and infected tissues.
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BACKGROUND: Saccharosydne procerus serves as a significant alternative host for parasitoids of the important rice pest, rice planthoppers. Rearing S. procerus on the water bamboo plants near rice field can provide a parasitic site for parasitic wasps during the idle period of rice fields, thereby stabilizing the number of parasitoids and suppressing the number of rice planthoppers in the field. However, limited understanding of genetic diversity of S. procerus restricts its application. Therefore, this study aims to analyze the genetic diversity of S. procerus in Hunan region. METHODS: In this study, 16 geographical populations of the S. procerus from the Hunan region were used. After screening, ISSR primers were employed for polymorphism detection. POPGENE32 software was used for genetic diversity analysis, and UPGMA clustering was applied for statistical analysis of different geographical populations to generate an evolutionary tree. RESULTS: Eleven ISSR primers were screened, resulting in the detection of 194 amplification locus, of which 126 were polymorphic. The average percentage of polymorphic locus was 64.95%. The mean Nei's gene diversity (H) was 0.2475, the mean Shannon's Information index (I) was 0.3708, and the Genetic diversity index among populations (Gst) was 0.3800. Cluster analysis identified three groups, with most populations concentrated in the second group, indicating no clear genetic structure. This suggests that the 16 populations of S. procerus exhibit high levels of genetic diversity.
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Variação Genética , Filogenia , China , Variação Genética/genética , Animais , Polimorfismo Genético , Repetições de Microssatélites/genética , Hemípteros/genética , Oryza/genética , Oryza/parasitologia , Genética Populacional/métodosRESUMO
BACKGROUND: Energy homeostasis is vital for insects to survive food shortages. This study investigated the starvation tolerance of Spodoptera frugiperda, which invaded China in 2019, focusing on its storage protein family, crucial for energy balance. 10 storage protein family members were identified and their expression patterns at different development stages and under different starvation stress were analyzed. METHODS AND RESULTS: We used qPCR to evaluate the expression levels of storage protein family members under various larval instars and starvation conditions. We discovered that, among above 10 members, only 2 storage proteins, SfSP8 and SfSP7 showed significant upregulation in response to starvation stress. Notably, SfSP8 upregulated markedly after 24 h of fasting, whereas SfSP7 exhibited a delayed response, with significant upregulation observed only after 72 h of starvation. Then we significantly reduced the starvation tolerance of larvae through RNAi-mediated knockdown of SfSP8 and also altered the starvation response of SfSP7 from a late to an early activation pattern. Finally, we constructed transgenic Drosophila melanogaster with heterologous overexpressing SfSP8 revealed that the starvation tolerance of the transgenic line was significantly stronger than that of wild-type lines. CONCLUSIONS: SfSP8 was the core storage protein member that mediated the starvation tolerance of larvae of S. frugiperda. Our study on the novel function of storage proteins in mediating larval starvation tolerance of S. frugiperda is conducive to understanding the strong colonization of this terrible invasive pest.
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Proteínas de Insetos , Larva , Spodoptera , Inanição , Animais , Spodoptera/genética , Larva/genética , Larva/metabolismo , Inanição/genética , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Animais Geneticamente Modificados , Estresse Fisiológico/genéticaRESUMO
The development of effective antibacterial drugs to combat bacterial infections, particularly the biofilm-related infections, remains a challenge. There are two important features of bacterial biofilms, which are well-known critical factors causing biofilms hard-to-treat in clinical, including the dense and impermeable extracellular polymeric substances (EPS) and the metabolically repressed dormant and persistent bacterial population embedded. These characteristics largely increase the difficulty for regular antibiotic treatment due to insufficient penetration into EPS. In addition, the dormant bacteria are insensitive to the growth-inhibiting mechanism of traditional antibiotics. Herein, we explore the potential of a series of new oligopyridinium-based oligomers bearing a multi-biomacromolecule targeting function as the potent bacterial biofilm eradication agent. These oligomers were rationally designed to be "charge-on-backbone" that can offer a special alternating amphiphilicity. This novel and unique feature endows high affinity to bacterial membrane lipids, DNAs as well as proteins. Such a broad multi-targeting nature of molecules not only enables its penetration into EPS, but also plays vital roles in the bactericidal mechanism of action that is highly effective against dormant and persistent bacteria. Our in vitro, ex vivo, and in vivo studies demonstrated that OPc3, one of the most effective derivatives, was able to offer excellent antibacterial potency against a variety of bacteria and effectively eliminate biofilms in zebrafish models and mouse wound biofilm infection models.
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Infecções Bacterianas , Peixe-Zebra , Animais , Camundongos , Biofilmes , Bactérias , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Infecções Bacterianas/tratamento farmacológico , Infecções Bacterianas/microbiologiaRESUMO
Single Fe sites have been explored as promising catalysts for the CO2 reduction reaction to value-added CO. Herein, we introduce a novel molten salt synthesis strategy for developing axial nitrogen-coordinated Fe-N5 sites on ultrathin defect-rich carbon nanosheets, aiming to modulate the reaction pathway precisely. This distinctive architecture weakens the spin polarization at the Fe sites, promoting a dynamic equilibrium of activated intermediates and facilitating the balance between *COOH formation and *CO desorption at the active Fe site. Notably, the synthesized FeN5, supported on defect-rich in nitrogen-doped carbon (FeN5@DNC), exhibits superior performance in CO2RR, achieving a Faraday efficiency of 99% for CO production (-0.4 V vs. RHE) in an H-cell, and maintaining a Faraday efficiency of 98% at a current density of 270 mA cm-2 (-1.0 V vs. RHE) in the flow cell. Furthermore, the FeN5@DNC catalyst is assembled as a reversible Zn-CO2 battery with a cycle durability of 24 hours. In-situ IR spectroscopy and density functional theory (DFT) calculations reveal that the axial N coordination traction induces a transformation in the crystal field and local symmetry, therefore weakening the spin polarization of the central Fe atom and lowering the energy barrier for *CO desorption.
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BACKGROUND: Cyproflanilide is a novel chemical that is already undergoing insecticide registration in China and has been categorized as a member of group 30 by the IRAC. Since it was first detected in 2019, the fall armyworm (FAW), Spodoptera frugiperda, has become a serious pest in China. Our laboratory and field efficacy trials indicated that cyproflanilide exhibits high larvicidal activity against FAW. However, the effect of cyproflanilide against FAW remains unknown. And it is worth exploring further before the cyproflanilide becomes commercially available. RESULTS: We found larvae exposed to cyproflanilide had significantly shorter body length and higher death rates compared to control larvae. Additionally, we found surviving larvae had a significantly longer developmental period compared to control larvae. The potential molecular mechanisms of cyproflanilide against FAW were investigated using comparative transcriptomic analyses on larval samples subjected to three insecticide treatments, including cyproflanilide and two other commonly used insecticides against FAW in China, chlorantraniliprole and avermectin. We found that several subunits of the γ-aminobutyric acid receptor (GABAR), a possible target protein of cyproflanilide, were significantly up-regulated at the transcriptional level during cyproflanilide-induced stress. Additionally, between the control and cyproflanilide-treated samples, we identified 131 differentially expressed genes (DEGs) associated with detoxification metabolism. Of these, we found four P450 genes that were significantly up-regulated under cyproflanilide stress but were not DEGs when exposed to chlorantraniliprole and avermectin, or 23 other pesticides from previous reports. Furthermore, we discovered an interesting gene aggregation region for insect cuticle proteins (CPs) on the 18th chromosome, which is likely related to FAW cross-resistance to cyproflanilide and avermectin. CONCLUSIONS: Our results contribute to a greater understanding of the mechanisms by which cyproflanilide affects FAW. Additionally, we identified the similarities and differences in transcriptomic profiling of FAW between the novel insecticide cyproflanilide and two other commonly used insecticides.
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Inseticidas , Animais , Inseticidas/farmacologia , Inseticidas/metabolismo , Spodoptera/metabolismo , Transcriptoma , Resistência a Inseticidas/genética , Larva/genéticaRESUMO
Since the Covid-19 epidemic, it has been clear that the availability of small and affordable drugs that are able to efficiently control viral infections in humans is still a challenge in medicinal chemistry. The synthesis and biological activities of a series of hybrid molecules that combine an emodin moiety and other structural moieties expected to act as possible synergistic pharmacophores in a single molecule were studied. Emodin has been reported to block the entry of the SARS-CoV-2 virus into human cells and might also inhibit cytokine production, resulting in the reduction of pulmonary injury induced by SARS-CoV-2. The pharmacophore associated with emodin was either a polyamine residue (emodin-PA series), a choice driven by the fact that a natural alkyl PA like spermine and spermidine play regulatory roles in immune cell functions, or a diphenylmethylpiperazine derivative of the norchlorcyclizine series (emoxyzine series). In fact, diphenylmethylpiperazine antagonists of the H1 histamine receptor display activity against several viruses by multiple interrelated mechanisms. In the emoxyzine series, the most potent drug against SARS-CoV-2 was (R)-emoxyzine-2, with an EC50 value = 1.9 µM, which is in the same range as that of the reference drug remdesivir. However, the selectivity index was rather low, indicating that the dissociation of antiviral potency and cytotoxicity remains a challenge. In addition, since emodin was also reported to be a relatively high-affinity inhibitor of the virulence regulator FIKK kinase from the malaria parasite Plasmodium vivax, the antimalarial activity of the synthesized hybrid compounds has been evaluated. However, these molecules cannot efficiently compete with the currently used antimalarial drugs.
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Antimaláricos , COVID-19 , Emodina , Plasmodium , Humanos , SARS-CoV-2 , Emodina/farmacologia , Antimaláricos/farmacologiaRESUMO
We present the complete genome sequence of an aviadenovirus obtained by metagenomics from cloacal swabs taken from a free-living Eurasian scops owl (Otus scops, a small raptor distributed in Europe and several parts of Asia) in China. Thirty protein coding genes were predicted in this 40,239-bp-long genome, which encodes the largest fiber protein among all reported aviadenoviruses. The viral genome sequence is highly divergent, and the encoded proteins have an average of only 55% amino acid sequence identity to those of other adenoviruses. In phylogenetic analysis, the new owl virus grouped with members of the genus Aviadenovirus and formed a common clade with another owl adenovirus reported previously in Japan. This is the second complete genome sequence of an aviadenovirus discovered in owls, and its proteins have an average of 62% amino acid sequence identity to those of the previously reported owl adenovirus. Combining this result with comparative genomic analysis of all aviadenoviruses, we propose that this owl virus and the previously described Japanese owl adenovirus can be assigned to two new species in the genus Aviadenovirus. This study provides new data on the diversity of aviadenoviruses in wild birds.
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Infecções por Adenoviridae , Aviadenovirus , Estrigiformes , Animais , Adenoviridae/genética , Aviadenovirus/genética , Filogenia , Genoma Viral , Infecções por Adenoviridae/veterináriaRESUMO
Eutrophication and exotic species invasion are key drivers of the global loss of biodiversity and ecosystem functions in lakes. We selected two exotic plants (Alternanthera philoxeroides and Myriophyllum aquaticum) and two native plants (Myriophyllum spicatum and Vallisneria spinulosa) to elucidate the effect of eutrophication on exotic plant invasiveness. We found that (1) elevated nutrient favored invasion of exotic species and inhibited growth of native plants. Species combinations and plant densities of native plants had limited effects on the resistance to invasion of the exotics. (2) A. philoxeroides featured the tightest connectivity among traits, which is consistent with its high competitive ability. Although eutrophication caused physiological stress to A. philoxeroides, it could effectively regulate enzyme activity and alleviate the stress. (3) M. aquaticum possessed strong tolerance to habitat disturbance and was highly disruptive to the surrounding plants. Eutrophication will exacerbate the adverse effects of M. aquaticum on the littoral ecosystem. (4) Nutrient enrichment reduced the biomass and relative growth rates of V. spinulosa and lowered phenolics and starch contents of M. spicatum, thereby making them more susceptible to habitat fluctuations. Overall, our study highlights how eutrophication alters the invasiveness of exotic plants and the resistance of native plants in the littoral zone, which is of relevance in a world with intensified human activities.
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Ecossistema , Lagos , Humanos , Espécies Introduzidas , Plantas , EutrofizaçãoRESUMO
BACKGROUND: Chlorantraniliprole is a diamide insecticide widely used in China over the last 15 years. The fall armyworm (FAW), Spodoptera frugiperda, newly invaded China in 2019. The response of FAW to chlorantraniliprole deserves more attention, in the context of many destructive lepidopteran species are resistant to diamide insecticides and the patent on core chemical of chlorantraniliprole in China expired in August 2022. METHODS AND RESULTS: This study investigated the response profile in larvae under chlorantraniliprole-induced (LC50) stress using methods of bioassay, RNA-Seq and qPCR. We observed growth inhibition and lethal effects in FAW larvae, but at a relatively high LC50 value compared to other several pests. Additionally, under chlorantraniliprole-induced stress, 3309 unigenes were found to be differentially expressed genes. The impacted genes included 137 encoding for detoxification enzymes, 29 encoding for cuticle proteins, and 20 key enzymes involved in the chitin metabolism, which all associated with metabolic resistance. Finally, we obtained the single nucleotide polymorphisms (SNPs) of two RyR genes, which are the target proteins for chlorantraniliprole. We also investigated the causes of the high LC50 value in our FAW, which possibly related to the stabilized 4743 M on SNP frequency of RyR. These findings documented the genetic background of RyR of FAW and indicated that application of chlorantraniliprole has a high risk of controlling FAW in China. CONCLUSION: In brief, our results provide a better understanding of the mechanisms of chlorantraniliprole toxicity and detoxification in FAW, and will aid in monitoring the development of resistant strains for a newly pest to an old insecticide.
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Inseticidas , Animais , Inseticidas/toxicidade , Spodoptera/genética , Transcriptoma/genética , Diamida/farmacologia , Resistência a Inseticidas/genética , Larva/genéticaRESUMO
Chilo suppressalis is one of the most damaging rice pests in China's rice-growing regions. Chemical pesticides are the primary method for pest control; the excessive use of insecticides has resulted in pesticide resistance. C. suppressalis is highly susceptible to cyproflanilide, a novel pesticide with high efficacy. However, the acute toxicity and detoxification mechanisms remain unclear. We carried out a bioassay experiment with C. suppressalis larvae and found that the LD10, LD30 and LD50 of cyproflanilide for 3rd instar larvae was 1.7 ng/per larvae, 6.62 ng/per larvae and 16.92 ng/per larvae, respectively. Moreover, our field trial results showed that cyproflanilide had a 91.24% control efficiency against C. suppressalis. We investigated the effect of cyproflanilide (LD30) treatment on the transcriptome profiles of C. suppressalis larvae and found that 483 genes were up-regulated and 305 genes were down-regulated in response to cyproflanilide exposure, with significantly higher CYP4G90 and CYP4AU10 expression in the treatment group. The RNA interference knockdown of CYP4G90 and CYP4AU10 increased mortality by 20% and 18%, respectively, compared to the control. Our results indicate that cyproflanilide has effective insecticidal toxicological activity, and that the CYP4G90 and CYP4AU10 genes are involved in detoxification metabolism. These findings provide an insight into the toxicological basis of cyproflanilide and the means to develop efficient resistance management tools for C. suppressalis.
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Bacillus thuringiensis , Inseticidas , Mariposas , Oryza , Praguicidas , Animais , Praguicidas/farmacologia , Bacillus thuringiensis/genética , Transcriptoma , Controle Biológico de Vetores/métodos , Plantas Geneticamente Modificadas/genética , Proteínas de Bactérias/metabolismo , Mariposas/genética , Inseticidas/toxicidade , Inseticidas/metabolismo , Larva/genética , Oryza/genéticaRESUMO
Aquaporins are important transmembrane water transport proteins which transport water and several neutral molecules. However, how aquaporins are involved in the synergistic transport of Mg2+ and water remains poorly understood. Here, we found that the cassava aquaporin MePIP2;7 was involved in Mg2+ transport through interaction with MeMGT9, a lower affinity magnesium transporter protein. Knockdown of MePIP2;7 in cassava led to magnesium deficiency in basal mature leaves with chlorosis and necrotic spots on their edges and starch over-accumulation. Mg2+ content was significantly decreased in leaves and roots of MePIP2;7-RNA interference (PIP-Ri) plants grown in both field and Mg2+ -free hydroponic solution. Xenopus oocyte injection analysis verified that MePIP2;7 possessed the ability to transport water only and MeMGT9 was responsible for Mg2+ efflux. More importantly, MePIP2;7 improved the transportability of Mg2+ via MeMGT9 as verified using the CM66 mutant complementation assay and Xenopus oocytes expressing system. Yeast two-hybrid, bimolecular fluorescence complementation, co-localization, and co-immunoprecipitation assays demonstrated the direct protein-protein interaction between MePIP2;7 and MeMGT9 in vivo. Mg2+ flux was significantly elevated in MePIP2;7-overexpressing lines in hydroponic solution through non-invasive micro-test technique analysis. Under Mg2+ -free condition, the retarded growth of PIP-Ri transgenic plants could be recovered with Mg2+ supplementation. Taken together, our results demonstrated the synergistic effect of the MePIP2;7 and MeMGT9 interaction in regulating water and Mg2+ absorption and transport in cassava.
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Aquaporinas , Manihot , Manihot/genética , Aquaporinas/genética , Aquaporinas/metabolismo , Transporte Biológico , Água/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Raízes de Plantas/metabolismoRESUMO
Chilo suppressalis is one of the most prevalent and damaging rice pests, causing significant economic losses each year. Chemical control is currently the primary method of controlling C. suppressalis. However, the indiscriminate use of chemical insecticides increases pest resistance, pollutes the environment and poses a significant health threat to humans and livestock, highlighting the need to find safer, more pest-specific and more effective alternatives to pest control. Plant-mediated RNA interference (RNAi) is a promising agricultural pest control method that is highly pest-specific and has less of an impact on the environment. Using multi-sgRNAs/Cas9 technology to delete Fatty acyl-CoA reductase (FAR) of C. suppressalis in the G0 generation, we show that downregulating FAR transcription may significantly increase the mortality rate and darken the epidermis of C. suppressalis compared with the control. Subsequently, we developed dsFAR transgenic rice lines using Agrobacterium-mediated genetic transformation and then screened three strains expressing dsFAR at high levels using transcriptional level analysis. Using transgenic rice stems, a laboratory feeding bioassay indicated that at least one line (L#10) displayed a particularly high level of insect resistance, with an insect mortality rate of more than 80%. In the field trials, dsFAR transgenic rice displayed high levels of resistance to C. suppressalis damage. Collectively, these results suggest the potential of a new environment-friendly, species-specific strategy for rice pest management.
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Oryza , Aldeído Oxirredutases , Oryza/genética , RNA de Plantas , TransgenesRESUMO
Determination of the correct water surface height (WSH) from green laser (532 nm) echoes alone in bathymetry LiDAR is challenging, as the green laser return near the water surface involves both specular reflection from the air-water interface and backscattered return from the water volume. In this paper, a low-complexity method based on linear approximation of the leading edge (LLE) is proposed. The results of this LLE method were compared with those of three common algorithms of peak detection, half peak power, and surface-volume-bottom implemented on airborne datasets with various surface roughness conditions. In addition, the method was evaluated in waters with a wide range of optical properties through a controllable tank experiment. The uncertainties in the WSHs of all algorithms were greater when the water volume backscattering dominated the surface return; they were sensitive to variations in the optical properties of water, and increased exponentially with decreasing LiDAR attenuation coefficient (KLiDAR). Comparatively, the LLE algorithm had the fastest computational speed and demonstrated the best performance in situations where specular reflection or volume backscatter return was dominant, with average and maximum errors of less than 0.06 and 0.13 m, respectively.
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BACKGROUND: The nutritional signaling pathway regulates an insect's size, development, and lifespan, as well as playing a vital role in reproduction. The insulin/insulin-like growth factor signaling (IIS) pathway plays a key role in the nutrition signaling pathway. As an integral component of the IIS pathway, insulin receptor (InR), a receptor tyrosine kinase, plays a role in the insulin pathway by controlling reproduction in many insect species. However, the precise molecular function of InR in non-model insect reproduction is poorly understood. METHODS: In our study, Chilo suppressalis, a well-known rice pest, was used as a molecular system to determine the role of InR in insect reproduction. Sequencing the InR gene of C. suppressalis, comparing the amino acid sequence-specific structure, and constructing a phylogenetic tree revealed that this gene has four main domains: ligand binding L domain, Furin-like region, fibronectin type III domains, and Tyrosine kinase catalytic domain, which were all highly conserved in insects. RESULTS: By characterizing the spatiotemporal expression profile of InR in different developmental stages and tissues, we found that InR gene expression was highest on the 3-day old in female pupae, 6th instar larvae, and fat body on the 6-day old in female pupae. InR gene expression may promote the molting and pupation of larvae and play a role in reproduction in the fat body. Furthermore, the RNA interference knockdown of InR dramatically reduced yolk deposition and blocked oocyte maturation. After suppression of InR, the expression of several other genes fluctuated to varying degrees. CONCLUSION: In conclusion, InR is vital to reproduction and is expected to become a new target for pest management.
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Insulinas , Mariposas , Animais , Interferência de RNA , Receptor de Insulina/genética , Receptor de Insulina/metabolismo , Filogenia , Mariposas/genética , Larva/metabolismo , Insulinas/genética , Insulinas/metabolismoRESUMO
The changes of microbial communities of rhizospheric soil in different ages are speculated to cause soil-borne diseases and replanting problem in American ginseng (Panax quinquefolius L.) cultivation. This study analyzed the physicochemical properties and microbial communities of rhizospheric soil during the planting of American ginseng in the Wendeng area of Weihai, China. The water content and organic matter content of American ginseng rhizospheric soil decreased year by year. A decline in the diversity of bacteria and fungi was observed in the rhizospheric soils planting American ginseng compared with the traditional crop wheat in the control group. During the later planting stage, the abundances of Proteobacteria, Actinobacteria, and Basidiomycota were lower, whereas that of Acidobacteria, Firmicutes, and Mucoromycota were higher. Through the correlation analysis between environmental factors and microbial community, it was found that the content of soil phosphorus was significantly positively correlated with the root rot pathogen Fusarium. The results of functional prediction showed that the decrease of secondary metabolite synthesis of rhizospheric soil bacteria and the increase of plant pathogenic fungi may be the important reasons for the increase of diseases in the later stage of American ginseng planting. This study revealed the evolution of rhizosphere microbial community and function in the process of American ginseng planting, which is valuable for planting management.
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Microbiota , Panax , Bactérias/genética , Fungos , Panax/microbiologia , Rizosfera , Solo/química , Microbiologia do SoloRESUMO
A new lignan (4,4',5'-trihydroxy-5,3'-dimethoxy-3-O-9',2-(7'R)-lignan, 1) and eight C(6)-oxygenated flavonoids (2-9), including a newly identified flavonoid (7,3',4'-trihydroxy-3,5,6-trimethoxyflavone, 2), were isolated from the inflorescence of Ambrosia artemisiifolia L. The structures of these isolates were determined using extensive spectroscopic analyses and comparison with data previously reported in the literature. The absolute configuration of compound 1 was established using electronic circular dichroism (ECD) spectrum. All the flavonoids (2-9) showed inhibitory effects on LPS-induced NO production in RAW264.7 cells, with the inhibition rate ranging from 24.51 % to 69.82 % at 50â µM. The inâ vitro cytotoxicity study showed that compounds 3-8 have a 60 % inhibition rate against SMMC-7721 at a concentration of 40â µM, while compounds 5 and 8 also exhibited inhibitory activity against HL-60 at 40â µM with the inhibition rate of 83.36 % and 52.01 %, respectively.
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Ambrosia , Lignanas , Ambrosia/química , Flavonoides/química , Flavonoides/farmacologia , Inflorescência , Lignanas/química , Lignanas/farmacologia , Estrutura MolecularRESUMO
The successful invasion of Ambrosia artemisiifolia is largely due to allelopathy. As an invasive alien plant, A. artemisiifolia has spread rapidly in Asia and Europe. Studies have shown that sesquiterpenoids play an important role in plant allelopathy. However, it is unclear whether the inflorescence of A. artemisiifolia also contains allelopathic components. In this paper, our phytochemical research focuses on the inflorescence of A. artemisiifolia. Twenty sesquiterpenoids, including four new ones (1-4) were isolated through successive chromatographic columns and identified by spectroscopic methods. At a concentration of 200 µg/mL, all the compounds tested were evaluated for their allelopathic activities on seedling growth of wheat. Our results indicate that nine compounds inhibited both the root and shoot growth of seedlings. Compounds 14, 15, 17, and 20 significantly inhibited root length, which was more than 50% shorter than the control. This study identified the chemical profile of the sesquiterpenoids occurring in the inflorescence of A. artemisiifolia. The bioactivity screening results provide further understanding of the chemical basis of allelopathy in A. artemisiifolia.
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Ambrosia , Sesquiterpenos , Alelopatia , Ambrosia/química , Inflorescência , Plântula , Sesquiterpenos/química , Sesquiterpenos/farmacologiaRESUMO
Heavy metal pollution is a global problem although its sources and trends differ by region and time. To data, no published research has reported heavy metal pollution in global rivers and lakes. This study reviewed past sampling data across six continents from 1970 to 2018 and analyzed the trends and sources of 10 heavy metal species in sediments from 289 rivers and 133 lakes. Collectively, river sediments showed increasing trends in Cd, Cr, Ni, Mn, and Co and decreasing trends in Hg, indicating that rivers acted as a sink for the former and a source for the latter. Lake sediments showed increasing trends in Pb, Hg, Cr, and Mn, and decreasing trends in Cd, Zn, and As, indicating that lakes acted as a sink for the former and a source for the latter. Due to difference in natural backgrounds and development stage in continents, mean metal concentrations were generally higher in Europe and North America than in Africa, Asia, and South America. Principal component analysis showed that main metal source was mining and manufacturing from the 1970s to 1990s and domestic waste discharge from the 2000s to 2010s. Metal sources in sediments differed greatly by continent, with rock weathering dominant in Africa, mining and manufacturing dominant in North America, and domestic waste discharge dominant in Asia and Europe. Global trends in sediment metal loads and pollution-control measures suggest that the implementation of rigorous standards on metal emissions, limitations on metal concentrations in manufactured products, and the pretreatment of metal-contaminated waste have been effective at controlling heavy metal pollution in rivers and lakes. Thus, these efforts should be extended globally.
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Metais Pesados , Poluentes Químicos da Água , China , Monitoramento Ambiental , Sedimentos Geológicos , Lagos , Metais Pesados/análise , Medição de Risco , Rios , Poluentes Químicos da Água/análiseRESUMO
In this study, the concentrations of six toxic metals (Cd, Cr, Cu, Ni, Pb, and Zn) in surface sediments within the Yangtze, Yellow, Pearl, and Liaohe rivers, China, were analyzed, and their associated pollution statuses and potential ecological risks were assessed using the geoaccumulation index (Igeo), sediment quality guidelines (SQGs), and the potential ecological risk index (RI). Relatively high toxic metal concentrations were observed in the Pearl and Yangtze rivers, whereas relatively low concentrations were observed in the Yellow and Liaohe rivers. In the Yangtze, Pearl, and Liaohe rivers, the concentrations of these six toxic metals were higher than their background values. Based on the SQGs, the concentrations of Cd, Cr, and Cu in the four rivers were found to be higher than the threshold effect levels (TELs) but lower than the probable effect levels (PELs); however, the concentration of Ni exceeded the PEL in the Pearl River sediments. The Igeo index indicated that all four rivers were heavily contaminated with Cd. The RI of the Pearl and Yellow rivers was classed as high and low, respectively, and that of the Yangtze and Liaohe rivers as moderate. The pollution status of the sediments in the four major rivers was explored in relation to the geochemical background, the ecological toxicity of metals, and the sensitivity of the local benthic communities. These results provide meaningful information for directing river management priorities.