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1.
Annu Rev Biochem ; 89: 821-851, 2020 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-32228045

RESUMO

Natural rubber (NR), principally comprising cis-1,4-polyisoprene, is an industrially important natural hydrocarbon polymer because of its unique physical properties, which render it suitable for manufacturing items such as tires. Presently, industrial NR production depends solely on latex obtained from the Pará rubber tree, Hevea brasiliensis. In latex, NR is enclosed in rubber particles, which are specialized organelles comprising a hydrophobic NR core surrounded by a lipid monolayer and membrane-bound proteins. The similarity of the basic carbon skeleton structure between NR and dolichols and polyprenols, which are found in most organisms, suggests that the NR biosynthetic pathway is related to the polyisoprenoid biosynthetic pathway and that rubber transferase, which is the key enzyme in NR biosynthesis, belongs to the cis-prenyltransferase family. Here, we review recent progress in the elucidation of molecular mechanisms underlying NR biosynthesis through the identification of the enzymes that are responsible for the formation of the NR backbone structure.


Assuntos
Hemiterpenos/biossíntese , Hevea/metabolismo , Látex/biossíntese , Proteínas de Plantas/química , Borracha/química , Transferases/química , Antígenos de Plantas/genética , Antígenos de Plantas/metabolismo , Clonagem Molecular , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Hemiterpenos/química , Hemiterpenos/metabolismo , Hevea/química , Hevea/genética , Látex/química , Látex/metabolismo , Modelos Moleculares , Compostos Organofosforados/química , Compostos Organofosforados/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Domínios e Motivos de Interação entre Proteínas , Multimerização Proteica , Estrutura Secundária de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Borracha/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Terpenos/química , Terpenos/metabolismo , Transferases/genética , Transferases/metabolismo
2.
Langmuir ; 40(17): 9197-9204, 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38639710

RESUMO

Waterborne coatings with intrinsic antibacterial attributes have attracted significant attention due to their potential in mitigating microbial contamination while simultaneously addressing the environmental drawbacks of their solvent-based counterparts. Typically, antimicrobial coatings are designed to resist and eliminate microbial threats, encompassing challenges such as biofilm formation, fungal contamination, and proliferation of black mold. Iodine, when solubilized using ethylene glycol and incorporated as a complex into waterborne latex dispersions, has shown remarkable antimicrobial activity. Here, we demonstrate the effect of the film formation process of these iodinated latex dispersions on their antimicrobial properties. The effect of iodine on the surface morphology and mechanical, adhesion, and antimicrobial properties of the generated films was investigated. Complete integration and uniform distribution of iodine in the films were confirmed through UV-vis spectrophotometry and a laser Raman imaging system (LRIS). In terms of properties, iodinated films showed improved mechanical strength and adhesion compared with blank films. Further, the presence of iodine rendered the films rougher, making them susceptible to bacterial adhesion, but interestingly provided enhanced antibiofilm activity. Moreover, thicker films had a lower surface roughness and reduced biofilm growth. These observations are elucidated through the complex interplay among film thickness, surface morphology, and iodine properties. The insights into the interlink between the film formation process and antimicrobial properties of iodinated latex dispersions will facilitate their enhanced application as sustainable alternatives to solvent-based coatings.


Assuntos
Biofilmes , Iodo , Látex , Látex/química , Látex/farmacologia , Iodo/química , Iodo/farmacologia , Biofilmes/efeitos dos fármacos , Propriedades de Superfície , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Antibacterianos/farmacologia , Antibacterianos/química , Aderência Bacteriana/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Halogenação
3.
Biomacromolecules ; 25(10): 6580-6590, 2024 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-39303012

RESUMO

The thiol-ene emulsion polymerization of three dienes synthesized from bioderived compounds, and subsequent preparation of core-shell polymer latexes, is reported. Levoglucosan (LGA), levogucosenone (LGO) and isosorbide were first modified with 4-pentenoic acid to install polymerizable groups. These monomers were used along with a dithiol to prepare poly(thioether) particles via ab initio emulsion polymerization using potassium persulfate as initiator and sodium dodecyl sulfate as surfactant. The structure of the diene significantly influenced the size of the resulting polymer latex particles. Given their low glass transition temperature, the LGA-derived poly(thioether) particles were used as a seed for the seeded emulsion polymerization of either styrene or methyl methacrylate. Core-shell latex particles with a high Tg core and a low Tg bioderived shell were formed, as verified by electron microscopy and in agreement with theoretical predictions of the equilibrium particle morphology based on the interfacial tensions of each particle phase.


Assuntos
Emulsões , Látex , Polimerização , Compostos de Sulfidrila , Emulsões/química , Compostos de Sulfidrila/química , Látex/química , Tamanho da Partícula , Polímeros/química
4.
Biomacromolecules ; 25(5): 3018-3032, 2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38648261

RESUMO

Different cellulose nanocrystal (CNC) forms (dried vs never-dried) can lead to different degrees of CNC reassembly, the formation of nanofibril-like structures, in nanocomposite latex-based pressure-sensitive adhesive (PSA) formulations. CNC reassembly is also affected by CNC sonication and loading as well as the protocol used for CNC addition to the polymerization. In this study, carboxylated CNCs (cCNCs) were incorporated into a seeded, semibatch, 2-ethylhexyl acrylate/methyl methacrylate/styrene emulsion polymerization and cast as pressure-sensitive adhesive (PSA) films. The addition of CNCs led to a simultaneous increase in tack strength, peel strength, and shear adhesion, avoiding the typical trade-off between the adhesive and cohesive strength. Increased CNC reassembly resulted from the use of dried, redispersed, and sonicated cCNCs, along with increased cCNC loading and addition of the cCNCs at the seed stage of the polymerization. The increased degree of CNC reassembly was shown to significantly increase the shear adhesion by enhancing the elastic modulus of the PSA films.


Assuntos
Adesivos , Celulose , Látex , Nanopartículas , Celulose/química , Adesivos/química , Nanopartículas/química , Látex/química , Polimerização , Nanocompostos/química , Pressão
5.
Biomacromolecules ; 25(6): 3823-3830, 2024 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-38773865

RESUMO

Sustainability and circularity are key issues facing the global polymer industry. The search for biodegradable and environmentally-friendly polymers that can replace conventional materials is a difficult challenge that has been met with limited success. Alternatives must be cost-effective, scalable, and provide equivalent performance. We report that latexes made by the conventional emulsion polymerization of vinyl acetate and functional vinyl ester monomers are efficient thickeners for consumer products and biodegrade in wastewater. This approach uses readily-available starting materials and polymerization is carried out in water at room temperature, in one pot, and generates negligible waste. Moreover, the knowledge that poly(vinyl ester)s are biodegradable will lead to the design of new green polymer materials.


Assuntos
Emulsões , Emulsões/química , Polimerização , Polímeros/química , Álcalis/química , Biodegradação Ambiental , Látex/química , Compostos de Vinila/química , Águas Residuárias/química
6.
Macromol Rapid Commun ; 45(19): e2400314, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-38885940

RESUMO

The development of new materials for antifreezing and anti-icing applications is a big challenge in industry and academic area. Inspired by the antifreeze proteins, latex particles with superhydrophilic zwitterionic shells and superhydrophobic cores are synthesized by reversible addition-fragmentation chain transfer emulsion polymerization, and the applications of the latex particles in antifreezing and anti-icing applications are investigated. In antifreezing study, the critical aggregate temperature (CAT) of the latex particles decreases, and the separation of the melting and freezing temperature of ice increases with the particle concentration. Enzyme molecules can be cryopreserved in the particle solution, and their bioactivities are well maintained. Latex particles are casted into latex films with dynamic surfaces. Anti-icing performances, including antifrosting properties, freezing delay time, and ice adhesion strengths, are studied; and the water-treated latex films present stronger anti-icing properties than other films, due to the synergistic effects of the superhydrophilic and superhydrophobic components. In addition, latex particles with zwitterionic shells and poly(n-butyl methacrylate) cores, and latex particles with small molecular surfactant on the surfaces are synthesized. The antifreezing performances of the latex particles and anti-icing properties of the latex films are compared.


Assuntos
Interações Hidrofóbicas e Hidrofílicas , Látex , Látex/química , Propriedades de Superfície , Tamanho da Partícula , Congelamento , Proteínas Anticongelantes/química
7.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 55(4): 958-963, 2024 Jul 20.
Artigo em Zh | MEDLINE | ID: mdl-39170021

RESUMO

Objective: To investigate the biological safety of commercially available natural rubber latex and synthetic polyurethane condoms. Methods: Natural rubber latex condom brands of A1 and A2 and polyurethane condom brands of B1 and B2 were purchased from large chain pharmacies in Chengdu, with three packages randomly selected for each brand. The study assessed the toxic effects of condom extracts on L-929 mouse fibroblasts according to GB/T standards. Gross observation and histopathological evaluation were conducted to assess the irritation reactions of condoms on the vagina and penis of rabbits (3 rabbits were used for each brand), as well as their sensitization effects on guinea pig skin. Additionally, the impact of continuous perfusion of condom extracts of the vaginas of SD rats for 30 days on their reproductive systems was evaluated, following GB/T standards (5 rats were used for each brand). Results: Extracts from natural rubber latex condom brands A1 and A2, at concentrations of 100% and 50%, exhibited significant cytotoxicity, with optical density (OD) values being significantly lower than those of the blank control group and the polyurethane condom brands B1 and B2 (P<0.01). There was no significant difference in cell morphology and OD values between the extracts of B1 and B2 and the blank control group (P>0.05). Vaginal congestion was found in 3 rabbits from A1 group and 1 rabbit from the A2 group, while no obvious congestion was noted in rabbits from the B1 and the B2 groups. Histopathological examination showed scattered inflammatory cell infiltration in the vaginal tissue of 3 rabbits from the A1 group and 2 rabbits from the A2 group, and slight congestion in the blood vessels of the lamina propria. No obvious pathological changes were observed in the vaginal tissue of polyurethane brand rabbits. Two rabbits from the A1 group and 1 rabbit from the A2 group showed transient and mild erythema on the penis during the experiment. Histopathological examination showed that 1 rabbit from A1 group had small foci of pericapillary lymphocytes in the dermis of the penis, while no significant pathological changes were observed in the penile tissue of A2, B1, and B2 groups. After 30 days of continuous vaginal perfusion with condom extract, 3 rats in A1 group and 2 rats in the A2 group had uterine congestion, with the degree of congestion being lower in the A2 group. No significant congestion or pathological changes were observed in the vaginal and penile tissues of rabbits, or in the uterine tissues of rats from the polyurethane groups. None of the 4 groups of guinea pigs showed significant skin allergic reactions to the condom extracts. Conclusion: Significant differences in biosafety exist among condoms of various materials and brands. To ensure product safety, it is crucial to strengthen quality control and regulatory oversight after condoms become commercially available.


Assuntos
Preservativos , Látex , Poliuretanos , Ratos Sprague-Dawley , Animais , Coelhos , Feminino , Cobaias , Ratos , Masculino , Látex/química , Camundongos , Vagina/patologia , Fibroblastos/efeitos dos fármacos , Teste de Materiais , Borracha/efeitos adversos
8.
Biochem Biophys Res Commun ; 679: 205-214, 2023 10 30.
Artigo em Inglês | MEDLINE | ID: mdl-37708579

RESUMO

According to the fatty acid and headgroup compositions of the phospholipids (PL) from Hevea brasiliensis latex, three synthetic PL were selected (i.e. POPA: 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphate POPC: 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine and POPG: 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol) to investigate the effect of PL headgroup on the interactions with two major proteins of Hevea latex, i.e. Rubber Elongation Factor (REF1) and Small Rubber Particle Protein (SRPP1). Protein/lipid interactions were screened using two models (lipid vesicles in solution or lipid monolayers at air/liquid interface). Calcein leakage, surface pressure, ellipsometry, microscopy and spectroscopy revealed that both REF1 and SRPP1 displayed stronger interactions with anionic POPA and POPG, as compared to zwitterionic POPC. A particular behavior of REF1 was observed when interacting with POPA monolayers (i.e. aggregation + modification of secondary structure from α-helices to ß-sheets, characteristic of its amyloid aggregated form), which might be involved in the irreversible coagulation mechanism of Hevea rubber particles.


Assuntos
Hevea , Fosfolipídeos , Fosfolipídeos/metabolismo , Hevea/química , Hevea/metabolismo , Látex/química , Látex/metabolismo , Fatores de Alongamento de Peptídeos/metabolismo , Estrutura Secundária de Proteína
9.
J Chem Ecol ; 49(5-6): 287-298, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36847993

RESUMO

Plant latex is sequestered in laticiferous structures and exuded immediately from damaged plant tissues. The primary function of plant latex is related to defense responses to their natural enemies. Euphorbia jolkinii Boiss. is a perennial herbaceous plant that greatly threaten the biodiversity and ecological integrity of northwest Yunnan, China. Nine triterpenes (1-9), four non-protein amino acids (10-13) and three glycosides (14-16) including a new isopentenyl disaccharide (14), were isolated and identified from the latex of E. jolkinii. Their structures were established on the basis of comprehensive spectroscopic data analyses. Bioassay revealed that meta-tyrosine (10) showed significant phytotoxic activity, inhibiting root and shoot growth of Zea mays, Medicago sativa, Brassica campestris, and Arabidopsis thaliana, with EC50 values ranging from 4.41 ± 1.08 to 37.60 ± 3.59 µg/mL. Interestingly, meta-tyrosine inhibited the root growth of Oryza sativa, but promoted their shoot growth at the concentrations below 20 µg/mL. meta-Tyrosine was found to be the predominant constituent in polar part of the latex extract from both stems and roots of E. jolkinii, but undetectable in the rhizosphere soil. In addition, some triterpenes showed antibacterial and nematicidal effects. The results suggested that meta-tyrosine and triterpenes in the latex might function as defensive substances for E. jolkinii against other organisms.


Assuntos
Euphorbia , Triterpenos , Látex/química , Euphorbia/fisiologia , China , Triterpenos/química , Glicosídeos
10.
Biochemistry (Mosc) ; 88(11): 1956-1969, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38105212

RESUMO

Euphorbiaceae, also known as the spurge family, is a large group of flowering plants. Despite being tropical natives, they are now widespread. Due to its medicinal and commercial importance, this family of plants attracted a lot of attention in the scientific community. The distinctive characteristic of the family is production of milky latex, which is a rich source of several lectins, the proteins that bind carbohydrates. Although their function is unclear, they are believed to defend plants against damaging phytopathogenic microorganisms, insects, and predatory animals. Additionally, they serve as crucial metabolic regulators under a variety of stressors. Detection, separation, purification, and characterization of lectins from the Euphorbiaceae family - mostly from the latex of plants - began over 40 years ago. This effort produced over 35 original research papers that were published. However, no systematic review that compiles these published data has been presented yet. This review summarizes and describes several procedures and protocols employed for extraction and purification of lectins belonging to this family. Physicochemical properties and biological activities of the lectins, along with their medicinal and pharmacological properties, have also been analyzed. Additionally, using examples of ricin and ricin agglutinin, we have structurally analyzed characteristics of the lectin known as Ribosome Inactivating Protein Type II (RIP-Type II) that belongs to this family. We anticipate that this review article will offer a useful compendium of information on this important family of lectins, show the scientists involved in lectin research the gaps in our knowledge, and offer insights for future research.


Assuntos
Euphorbiaceae , Ricina , Animais , Ricina/química , Lectinas de Plantas/farmacologia , Látex/química , Plantas
11.
Int J Mol Sci ; 24(7)2023 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-37047430

RESUMO

As a renewable biomass material, nano-cellulose has been investigated as a reinforcing filler in rubber composites but has seen little success because of its strong inclination towards aggregating. Here, a bottom-up self-assembly approach was proposed by regenerating cellulose crystals from a mixture of cellulose solution and natural rubber (NR) latex. Different co-coagulants of both cellulose solution and natural rubber latex were added to break the dissolution equilibrium and in-situ regenerate cellulose in the NR matrix. The SEM images showed that the sizes and morphologies of regenerated cellulose (RC) varied greatly with the addition of different co-coagulants. Only when a 5 wt% acetic acid aqueous solution was used, the RC particles showed an ideal rod-like structure with small sizes of about 100 nm in diameter and 1.0 µm in length. The tensile test showed that rod-like RC (RRC)-endowed NR vulcanizates with pronounced reinforcement had a drastic upturn in stress after stretching to 200% strain. The results of XRD and the Mullins effect showed that this drastic upturn in stress was mainly attributed to the formation of rigid RRC-RRC networks during stretching instead of the strain-induced crystallization of NR. This bottom-up approach provided a simple way to ensure the effective utilization of cellulosic materials in the rubber industry.


Assuntos
Látex , Borracha , Borracha/química , Látex/química , Água , Excipientes
12.
Int J Mol Sci ; 24(23)2023 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-38069092

RESUMO

While fibrinolytic enzymes and thrombolytic agents offer assistance in treating cardiovascular diseases, the existing options are associated with a range of adverse effects. In our previous research, we successfully identified ficin, a naturally occurring cysteine protease that possesses unique fibrin and fibrinogenolytic enzymes, making it suitable for both preventing and treating cardiovascular disorders linked to thrombosis. Papain is a prominent cysteine protease derived from the latex of Carica papaya. The potential role of papain in preventing fibrino(geno)lytic, anticoagulant, and antithrombotic activities has not yet been investigated. Therefore, we examined how papain influences fibrinogen and the process of blood coagulation. Papain is highly stable at pH 4-11 and 37-60 °C via azocasein assay. In addition, SDS gel separation electrophoresis, zymography, and fibrin plate assays were used to determine fibrinogen and fibrinolysis activity. Papain has a molecular weight of around 37 kDa, and is highly effective in degrading fibrin, with a molecular weight of over 75 kDa. Furthermore, papain-based hemostatic performance was confirmed in blood coagulation tests, a blood clot lysis assay, and a κ-carrageenan rat tail thrombosis model, highlighting its strong efficacy in blood coagulation. Papain shows dose-dependent blood clot lysis activity, cleaves fibrinogen chains of Aα, Bß, and γ-bands, and significantly extends prothrombin time (PT) and activated partial thromboplastin time (aPTT). Moreover, the mean length of the infarcted regions in the tails of Sprague-Dawley rats with κ-carrageenan was shorter in rats administered 10 U/kg of papain than in streptokinase-treated rats. Thus, papain, a cysteine protease, has distinct fibrin and fibrinogenolytic properties, suggesting its potential for preventing or treating cardiovascular issues and thrombosis-related diseases.


Assuntos
Carica , Cisteína Proteases , Hemostáticos , Trombose , Ratos , Animais , Fibrinolíticos/farmacologia , Fibrinolíticos/química , Látex/química , Papaína , Anticoagulantes , Carragenina , Ratos Sprague-Dawley , Trombose/tratamento farmacológico , Fibrinogênio , Fibrina/química
13.
Molecules ; 28(23)2023 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-38067412

RESUMO

Euphorbia dentata (Euphorbiaceae), an invasive weed, is rarely eaten by herbivorous insects and could secrete a large amount of white latex, causing a serious threat to local natural vegetation, agricultural production and human health. In order to prevent this plant from causing more negative effects on humans, it is necessary to understand and utilize the chemical relationships between the latex of E. dentata and herbivorous insects. In this study, three new norsesquiterpenes (1-3), together with seven known analogues (4-10), were isolated and identified from the latex of E. dentata. All norsesquiterpenes (1-10) showed antifeedant and growth-inhibitory effects on H. armigera with varying levels, especially compounds 1 and 2. In addition, the action mechanisms of active compounds (1-3) were revealed by detoxifying enzyme (AchE, CarE, GST and MFO) activities and corresponding molecular docking analyses. Our findings provide a new idea for the development and utilization of the latex of E. dentata, as well as a potential application of norsesquiterpenes in botanical insecticides.


Assuntos
Euphorbia , Látex , Humanos , Mecanismos de Defesa , Euphorbia/química , Helicoverpa armigera , Látex/química , Simulação de Acoplamento Molecular , Animais
14.
J Sci Food Agric ; 103(2): 846-855, 2023 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-36071690

RESUMO

BACKGROUND: The achenes/seeds of endemic jelly fig (Ficus pumila var. awkeotsang) fruit have been applied to prepare a traditional beverage in Taiwan. Upon fruit harvest, jelly fig latex exuded from stalks was discarded. Protease activity was monitored in its latex. Proteases capable of hydrolyzing proteins have many application aspects based on diverse characteristics. Commercial plant proteases are frequently from latex. RESULTS: The latex protease of jelly fig, termed FaFicin, was purified to homogeneity with a molecular mass of ~32 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. According to liquid chromatographic-tandem mass spectrometric analyses, the expected protein band of protease was matched to ficin A, ficin B or chymopapain from common fig or papaya. Iodoacetamide, an inhibitor of cysteine protease, inhibited its protease activity completely. Hence FaFicin was identified as a papain-like cysteine protease (PLCP), exhibiting more than 80% and 70% activity as assayed at pH 5-8 and 40-70 °C, respectively. It maintained ~89% of initial activity after 120 min at 55 °C and pH 7. Moreover, FaFicin could degrade the myosin and actin of meat, and clot milk. CONCLUSION: The ficin FaFicin was obtained, purified and identified as a PLCP member from agricultural waste: jelly fig latex. It possessed activity under a wide range of pH values and temperature, and exhibited excellent thermostability. Based on its initial evaluation as a meat tenderizer and milk clotting reagent, the application of FaFicin was possible, which may extend utilization of jelly fig. © 2022 Society of Chemical Industry.


Assuntos
Cisteína Proteases , Ficus , Ficina/química , Ficina/metabolismo , Ficus/química , Látex/química , Alérgenos , Peptídeo Hidrolases
15.
Plant J ; 107(4): 1040-1055, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34053139

RESUMO

The hyperaccumulator Pycnandra acuminata is a New Caledonian rainforest tree known to have the highest concentration of nickel in any living organism, with 25 wt% nickel in its latex. All trees (with a diameter of >10 cm) and soil profiles in a 0.25-hectare permanent plot were sampled to assess the biogeochemical compartmentalisation of nickel in a dense stand of P. acuminata trees. Nickel stable isotope analysis permitted insights into the cycling of nickel in this ecosystem. The total tree biomass of the plot was calculated to be 281 tonnes ha-1 , which contained 0.44 kg of cobalt, 49.1 kg of manganese, 257 kg of nickel and 6.76 kg of zinc. Nickel stable isotope analysis identified the biotic origin of the nickel in the soil upper layers, with P. acuminata shoots enriched in lighter nickel isotopes. The δ60 Ni latex signature suggests that long-distance transport, radial xylem and phloem loading are at play in P. acuminata.


Assuntos
Florestas , Níquel/análise , Níquel/farmacocinética , Sapotaceae/metabolismo , Solo/química , Biomassa , Isótopos/análise , Látex/química , Metais Pesados/análise , Nova Caledônia , Folhas de Planta/química , Sapotaceae/efeitos dos fármacos , Oligoelementos/análise , Oligoelementos/farmacocinética , Árvores , Clima Tropical , Xilema/química
16.
J Mol Recognit ; 35(7): e2957, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35218251

RESUMO

Jatropha mollissima is endemic to Brazil and is used for traditional medicinal purposes, including the treatment of snakebite. In this study, latex obtained from this plant was fractioned using reversed-phase chromatography, and the fractions were then screened for peptides. A 755 g/mol peptide was obtained, and MS/MS analyses indicated it had a cyclic sequence (Pro-Leu-Gly-Val-Leu-Leu-Tyr). This peptide sequence was present in the Jatropha genome database, and an identity value of 90.71%, an E-value of 0.0, and a score of 883 with NO-associated protein 1/chloroplastic/mitochondria of Jatropha curcas were obtained from the NCBI nonredundant protein sequence (nr) database. Molecular docking analyses performed with the peptide against a metalloendopeptidase belonging to Crotalus adamanteus snake venom suggested the cyclic peptide establishes favorable interactions with the catalytic site of the enzyme. Therefore, it could inhibit enzyme catalysis. This belief was corroborated by the formation of 6 hydrogen bonds with the linear form of the peptide. Tighter complexation of the cyclic form (41 kcal/mol more energetic) revealed better spatial blocking. The linear form outperformed the cyclic form in complexing the required energy, recruiting more catalytic residues (6/2), and in establishing more hydrogen bonds (6/3). However, cyclic folding provided a more significant spatial block within the catalytic site. The set of results suggests that the cycle peptide, here called Jatromollistatin, which was previously described as jatrophidin and pohlianin A in two other species of Jatropha, is a promising candidate to inhibit venom proteases. This belief is corroborated by the topical use of the latex for initial treatment of snakebites.


Assuntos
Crotalus , Látex , Animais , Crotalus/genética , Látex/química , Metaloendopeptidases , Simulação de Acoplamento Molecular , Peptídeos/farmacologia , Peptídeos Cíclicos/química , Peptídeos Cíclicos/farmacologia , Espectrometria de Massas em Tandem
17.
Biotechnol Appl Biochem ; 69(6): 2580-2591, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34967474

RESUMO

The investigation of a plant glycosylated serine protease (EuRP-61) isolated from Euphorbia resinifera latex for potential antiplatelet and anticoagulation activities has been previously reported. In the present study, the protein sequence and native crystal structure of EuRP-61 were characterized. The structure was identified using single-wavelength anomalous diffraction with a refinement resolution of 1.7 Å (PDB ID: 7EOX). The main structural components of EuRP-61 were composed of three domains: catalytic, protease-associated (PA), and fibronectin type III (Fn3)-like domains. The crystal structure revealed that some loops in the PA and catalytic domains of EuRP-61 were different from the other subtilisin-like proteases (cucumisin and SBT3). These different loops might be involved in the general monomer formation of EuRP-61, substrate specificity, and maintenance of the catalytic domain. The Fn3-like domain may provide flexibility to the enzyme to bind with various substrates and cell receptors. Additionally, the active site of EuRP-61 consisted of the catalytic triad of Ser434, His106, and Asp32, similar to other serine proteases. The present study provides additional information and insight into the protease and antithrombotic activities of EuRP-61, which could contribute to further development of this enzyme for biomedical treatment.


Assuntos
Euphorbia , Látex/química , Serina Proteases/química , Sequência de Aminoácidos , Análise de Sequência
18.
J Sep Sci ; 45(18): 3491-3500, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35855582

RESUMO

The current method used in latex industries to determine the volatile fatty acids contents of Hevea brasiliensis latex is steam distillation. However, the accuracy of the method has been debated for some time. We assessed the accuracy of the method and developed a new, more reliable high-performance liquid chromatographic method of determining acids in latex. The volatile fatty acids (formic, acetic, propionic, butyric, and valeric acids) and nonvolatile organic acids (oxalic, malic, lactic, citric, and succinic acids) in latex are directly determined simultaneously for the first time with high sensitivity and without losses during sample preparation. To avoid errors from derivatization, an acid-resistant Prevail HPLC column and a gradient mobile phase of 25 mM potassium dihydrogen phosphate (pH 2.5) and acetonitrile were employed. Under optimum conditions, the calibrations of both types of acids demonstrated satisfactory correlation coefficients of  ≥0.990, with limits of detection ranging from 0.02 to 395 mM. The developed method demonstrated the profiles of acids in field and concentrated latex of the same batch. Moreover, the evolution of the profiles of all studied acids in both types of latex during a 3-month period was also revealed.


Assuntos
Hevea , Látex , Acetonitrilas , Ácidos/análise , Ácidos Graxos Voláteis , Hevea/química , Látex/química , Compostos Orgânicos/análise , Vapor , Succinatos
19.
J Asian Nat Prod Res ; 24(4): 311-320, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34142616

RESUMO

Five new triterpenoids named as euphatexols C - G (1-5) were isolated from the latex of Euphorbia resinifera. Their chemical structures were determined by extensive spectroscopic analysis, including IR, HRMS, 1 D and 2 D NMR data. Compounds 1-5 showed moderate anti-inflammatory activity with IC50 values of 22.30, 48.04, 21.89, 38.15 and 41.15 µM, respectively.


Assuntos
Euphorbia , Triterpenos , Anti-Inflamatórios , Euphorbia/química , Látex/química , Estrutura Molecular , Triterpenos/química , Triterpenos/farmacologia
20.
Int J Mol Sci ; 23(16)2022 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-36012145

RESUMO

IAN873, Dongfang93114 and Reyan73397, created through vegetative propagation for their high yield and excellent cold resistance, are major clones planted in China. In this work, latexes with rubber particles of the same size from these clones are separated from fresh natural rubber latex, and corresponding rubber films are prepared from each latex. The structure and components of each film are measured. This indicates that the characteristics of the rubbers obtained from latexes with similar particle sizes show some resembling trends among different clones, while for specific samples, those characteristics vary depending on the clone. The molecular weight is generally highest in IAN873 and lowest in Reyan73397. Rubber chains in small rubber particles are longer, and large rubber particles show a wider molecular weight distribution. The gel content of every sample from Reyan73397 is lower than the other two clones. The nitrogen content increases with the size of rubber particles in all clones. The ester content of small rubber particles in IAN873 and Reyan73397 is almost zero. Large rubber particles have more branching points formed via esters. This study provides a new perspective on the influence of clones on the relationship between characteristics of natural rubber and the size of rubber particles in natural rubber latex.


Assuntos
Látex , Borracha , Células Clonais , Látex/química , Peso Molecular , Proteínas de Plantas/química , Plantas
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