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1.
Genet Mol Biol ; 40(3): 591-596, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28863211

RESUMO

X-linked intellectual disability (XLID) has been associated with various genes. Diagnosis of XLID, especially for non-syndromic ones (NS-XLID), is often hampered by the heterogeneity of this disease. Here we report the case of a Chinese family in which three males suffer from intellectual disability (ID). The three patients shared the same phenotype: no typical clinical manifestation other than IQ score ≤ 70. For a genetic diagnosis for this family we carried out whole exome sequencing on the proband, and validated 16 variants of interest in the genomic DNA of all the family members. A missense mutation (c.710G > T), which mapped to exon 6 of the Rab GDP-Dissociation Inhibitor 1 (GDI1) gene, was found segregating with the ID phenotype, and this mutation changes the 237th position in the guanosine diphosphate dissociation inhibitor (GDI) protein from glycine to valine (p. Gly237Val). Through molecular dynamics simulations we found that this substitution results in a conformational change of GDI, possibly affecting the Rab-binding capacity of this protein. In conclusion, our study identified a novel GDI1 mutation that is possibly NS-XLID causative, and showed that whole exome sequencing provides advantages for detecting novel ID-associated variants and can greatly facilitate the genetic diagnosis of the disease.

2.
Bioorg Med Chem Lett ; 26(22): 5492-5496, 2016 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-27777007

RESUMO

A series of 12-oxime and O-oxime ether derivatives of dehydroabietic acid were synthesized and investigated for the antibacterial activity against Staphylococcus aureus Newman strain and five multidrug-resistant strains (NRS-1, NRS-70, NRS-100, NRS-108, and NRS-271). The aromatic oximate derivative 11a showed the highest activity with MIC of 0.39-0.78µg/mL against S. aureus Newman. Of note, compounds 10b, 11 and 14 showed the most potent antibacterial activity against five multidrug-resistant S. aureus with MIC values of 1.25-3.13µg/mL. These results offered useful information for further strategic optimization in search of the antibacterial candidates against infection of multidrug-resistant Gram-positive bacteria.


Assuntos
Abietanos/química , Abietanos/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Oximas/química , Oximas/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Abietanos/síntese química , Antibacterianos/síntese química , Farmacorresistência Bacteriana Múltipla , Humanos , Testes de Sensibilidade Microbiana , Oximas/síntese química , Infecções Estafilocócicas/tratamento farmacológico , Relação Estrutura-Atividade
3.
Plants (Basel) ; 13(11)2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38891236

RESUMO

Submerged macrophytes in eutrophic aquatic environments adapt to changes in ammonia nitrogen (NH4-N) levels by modifying their levels of free amino acids (FAAs) and soluble carbohydrates (SCs). As symbionts of submerged macrophytes, epiphytic bacteria have obvious host specificity. In the present study, the interspecific differences in the FAA and SC contents of Hydrilla verticillata (Linn. f.) Roylep, Vallisneria natans Hara and Chara braunii Gmelin and their leaf epiphytic bacterial communities were assessed in response to increased NH4-N concentrations. The results revealed that the response of the three submerged macrophytes to NH4-N stress involved the consumption of SCs and the production of FAAs. The NH4-N concentration had a greater impact on the variation in the FAA content, whereas the variation in the SC content was primarily influenced by the species. At the phylum level, the relative abundance of Nitrospirota on the leaves exhibited specific differences, with the order H. verticillata > V. natans > C. braunii. The dominant genera of epiphytic bacteria with denitrification effects on V. natans, H. verticillata and C. braunii leaves were Halomonas, Acinetobacter and Bacillus, respectively. When faced with NH4-N stress, the variation in epiphytic bacterial populations associated with ammonia oxidation and denitrification among submerged macrophytes could contribute to their divergent responses to heightened nitrogen levels.

4.
J Colloid Interface Sci ; 657: 327-333, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38043234

RESUMO

We have learned from the recent COVID-19 pandemic that the emergence of a new virus can quickly become a global health burden and kill millions of lives. Antiviral drugs are essential in our fight against viral diseases, but most of them are virus-specific and are prone to viral mutations. We have developed broad-spectrum antivirals based on multivalent nanoparticles grafted with ligands that mimic the target of viral attachment ligands (VALs). We have shown that when the ligand has a sufficiently long hydrophobic tail, the inhibition mechanism switches from reversible (virustatic) to irreversible (virucidal). Here, we investigate further how ligand density and particle size affect antiviral efficacy, both in terms of half-inhibitory concentration (IC50) and of reversible vs irreversible mechanism. We designed antiviral silica nanoparticles modified with 11-mercaptoundecane-1-sulfonic acid (MUS), a ligand that mimics heparan sulfate proteoglycans (HSPG) and we showed that these nanoparticles can be synthesized with different sizes (4-200 nm) and ligand grafting densities (0.59-10.70 /nm2). By testing these particles against herpes simplex virus type 2 (HSV-2), we show that within the size and density ranges studied, the antiviral IC50 is determined solely by equivalent ligand concentration. The nanoparticles are found to be virucidal at all sizes and densities studied.


Assuntos
Antivirais , Nanopartículas , Humanos , Antivirais/farmacologia , Ligantes , Pandemias , Herpesvirus Humano 2 , Nanopartículas/química
5.
ACS Appl Mater Interfaces ; 16(20): 26808-26816, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38728746

RESUMO

Glassy polymer dielectrics exhibit significant advantages in energy storage density and discharge efficiency; however, their potential application in thin-film capacitors is limited by the complexity of the production process, rising costs, and processing challenges arising from the brittleness of the material. In this study, a small amount of the polar monomer glycidyl methacrylate (GMA) was copolymerized with vinyl chloride (VC) using a highly integrated and precisely controlled process. This effectively facilitated the bulk synthesis of P(VC-GMA) copolymers, aimed at enhancing the dielectric properties and energy storage capabilities of the copolymer. Moreover, the incorporation of GMA into PVC induces significant alterations in the structural sequence of the copolymer, resulting in an enhancement of interchain interactions that ultimately contribute to an increase in the modulus and improved breakdown strength. With a GMA content of 2.4 mol %, P(VC-GMA) exhibits a significant enhancement in discharge energy density, surpassing that of a pure PVC copolymer, while maintaining high discharge efficiency and stability. The finding of this study paves the way for future advancements in high-energy-storage polymer dielectrics, thereby expanding the scope of advanced dielectric materials.

6.
ACS Appl Mater Interfaces ; 16(23): 29867-29875, 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38825754

RESUMO

Antimicrobial surfaces limit the spread of infectious diseases. To date, there is no antimicrobial coating that has widespread use because of short-lived and limited spectrum efficacy, poor resistance to organic material, and/or cost. Here, we present a paint based on waterborne latex particles that is supramolecularly associated with quaternary ammonium compounds (QACs). The optimal supramolecular pairing was first determined by immobilizing selected ions on self-assembled monolayers exposing different groups. The QAC surface loading density was then increased by using polymer brushes. These concepts were adopted to develop inexpensive paints to be applied on many different surfaces. The paint could be employed for healthcare and food production applications. Its slow release of QAC allows for long-lasting antimicrobial action, even in the presence of organic material. Its efficacy lasts for more than 90 washes, and importantly, once lost, it can readily be restored by spraying an aqueous solution of the QAC. We mainly tested cetyltrimethylammonium as QAC as it is already used in consumer care products. Our antimicrobial paint is broad spectrum as it showed excellent antimicrobial efficiency against four bacteria and four viruses.


Assuntos
Compostos de Amônio Quaternário , Compostos de Amônio Quaternário/química , Compostos de Amônio Quaternário/farmacologia , Anti-Infecciosos/farmacologia , Anti-Infecciosos/química , Pintura , Propriedades de Superfície , Látex/química , Látex/farmacologia , Testes de Sensibilidade Microbiana , Bactérias/efeitos dos fármacos
7.
Adv Mater ; : e2408294, 2024 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-39344918

RESUMO

In Nature, most known objects can perform their functions only when in supramolecular self-assembled from, e.g. protein complexes and cell membranes. Here, a dendritic polymer is presented that inhibits severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with an irreversible (virucidal) mechanism only when self-assembled into a Two-dimmensional supramolecular polymer (2D-SupraPol). Monomeric analogs of the dendritic polymer can only inhibit SARS-CoV-2 reversibly, thus allowing for the virus to regain infectivity after dilution. Upon assembly, 2D-SupraPol shows a remarkable half-inhibitory concentration (IC50 30 nM) in vitro and in vivo in a Syrian Hamster model has a good efficacy. Using cryo-TEM, it is shown that the 2D-SupraPol has a controllable lateral size that can be tuned by adjusting the pH and use small angle X-ray and neutron scattering to unveil the architecture of the supramolecular assembly. This functional 2D-SupraPol, and its supramolecular architecture are proposed, as a prophylaxis nasal spray to inhibit the virus interaction with the respiratory tract.

8.
ACS Cent Sci ; 10(5): 1012-1021, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38799657

RESUMO

Most viruses start their invasion by binding to glycoproteins' moieties on the cell surface (heparan sulfate proteoglycans [HSPG] or sialic acid [SA]). Antivirals mimicking these moieties multivalently are known as broad-spectrum multivalent entry inhibitors (MEI). Due to their reversible mechanism, efficacy is lost when concentrations fall below an inhibitory threshold. To overcome this limitation, we modify MEIs with hydrophobic arms rendering the inhibitory mechanism irreversible, i.e., preventing the efficacy loss upon dilution. However, all our HSPG-mimicking MEIs only showed reversible inhibition against HSPG-binding SARS-CoV-2. Here, we present a systematic investigation of a series of small molecules, all containing a core and multiple hydrophobic arms terminated with HSPG-mimicking moieties. We identify the ones that have irreversible inhibition against all viruses including SARS-CoV-2 and discuss their design principles. We show efficacy in vivo against SARS-CoV-2 in a Syrian hamster model through both intranasal instillation and aerosol inhalation in a therapeutic setting (12 h postinfection). We also show the utility of the presented design rules in producing SA-mimicking MEIs with irreversible inhibition against SA-binding influenza viruses.

9.
Langmuir ; 29(19): 5631-7, 2013 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-23627275

RESUMO

Dual-responsive capsules sensitive to pH and temperature changes were successfully prepared by grafting random copolymer brushes of 2-(2-methoxyethoxy)ethyl methacrylate (MEO2MA) and oligo(ethylene glycol) methacrylate (OEGMA) from polydopamine (Pdop)-coated SiO2 via a surface-initiated atom-transfer radical polymerization (SI-ATRP) method with subsequent removal of the SiO2 core. The uptake and release properties of the resulting capsules are highly affected by changes in the pH values and temperature of the solution. The capsules can take up cationic dye rhodamine 6G (Rh6G) at high pH and T < LCST but not at low pH and T > LCST. In contrast, the capsules can release Rh6G at pH < 7 and temperature below the LCST, but release is less efficient under the opposite conditions. This dual-responsive property was also observed for the anionic dye methyl orange.

10.
J Nanosci Nanotechnol ; 13(2): 1578-82, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23646685

RESUMO

A small-diameter vascular graft (inner diameter 4 mm) was fabricated from polyurethane (PU) and poly(ethylene glycol) (PEG) solutions by electrospinning technology. The fiber diameter decreased from 1023 +/-185 nm to 394 +/- 106 nm with increasing weight ratio of PEG in electrospinning solutions. The PU/PEG scaffolds showed randomly nanofibrous morphology and well-interconnected porous structure. The hydrophilicity of these scaffolds was improved significantly with increasing weight ratio of PEG. The mechanical properties of electrospun PU/PEG scaffolds were obviously different from that of pure PU scaffold, which was caused by plasticizing or hardening effect imparted by PEG composition. Under hydrated state, the PU/PEG scaffolds demonstrated low mechanical performance due to the hydrophilic property of materials. Compared with dry PU/PEG scaffolds with the same weight ratio of PEG, the tensile strength and elastic modulus of hydrated PU/PEG scaffolds decreased significantly, while the elongation at break increased. The results demonstrated that the electrospun PU/PEG hybrid tubular scaffolds are potential candidates for artificial blood vessels.

11.
Polymers (Basel) ; 15(11)2023 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-37299272

RESUMO

A rigid poly(vinyl chloride) foam with a cross-linked network structure was prepared by adding 3-glycidoxypropyltriethoxysilane (KH-561) into the universal formulation. The resulting foam had excellent heat resistance because of the increasing degree of cross-linking and number of Si-O bonds with a high heat resistance. The as-prepared foam was verified using Fourier-transform infrared spectroscopy (FTIR), energy-dispersive spectrometry (EDS) and foam residue (gel) analysis, which demonstrated that KH-561 was successfully grafted and cross-linked on the PVC chains. Finally, the effects of different KH-561 and NaHSO3 additions on the mechanical properties and heat resistance of the foams were studied. The results showed that the mechanical properties of the rigid cross-linked PVC foam were raised after adding a certain amount of KH-561 and NaHSO3. The residue (gel), decomposition temperature, and chemical stability of the foam significantly improved compared to the universal rigid cross-linked PVC foam (Tg = 72.2 °C). The Tg of the foam could reach 78.1 °C without any mechanical degradation. The results have important engineering application value regarding the preparation of lightweight, high-strength, heat-resistant, and rigid cross-linked PVC foam materials.

12.
J Mater Sci Mater Med ; 23(6): 1499-510, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22430593

RESUMO

Poly(ethylene glycol) methacrylate (PEGMA) was introduced into a polyurethane (PU) solution in order to prepare electrospun scaffold with improving the biocompatibility by electrospinning technology for potential application as small diameter vascular scaffolds. Crosslinked electrospun PU/PEGMA hybrid nanofibers were fabricated by a reactive electrospinning process with N,N'-methylenebisacrylamide as crosslinker and benzophenone as photoinitiator. The photoinduced polymerization and crosslinking reaction took place simultaneously during the electrospinning process. The electrospinning solutions with various weight ratios of PU/PEGMA were successfully electrospun. No significant difference in the scaffold morphology was found by SEM when PEGMA content was <20 wt%. The crosslinked fibrous scaffolds of PU/PEGMA exhibited higher mechanical strength than the pure PU scaffold. The hydrophilicity of scaffolds was controlled by varying the PU/PEGMA weight ratio. The tissue compatibility of electrospun nanofibrous scaffolds were tested using human umbilical vein endothelial cells (HUVECs). Cell morphology and cell proliferation were measured by SEM, fluorescence microscopy and thiazolyl blue assay (MTT) after 1, 3, 7 days of culture. The results indicated that the cell morphology and proliferation on the crosslinked PU/PEGMA scaffolds were better than that on the pure PU scaffold. Furthermore, the appropriate hydrophilic surface with water contact angle in the range of 55-75° was favorable of improvement the HUVECs adhesion and proliferation. Cells seeded on the crosslinked PU/PEGMA (80/20) scaffolds infiltrated into the scaffolds after 7 days of growth. These results indicated the crosslinked electrospun PU/PEGMA nanofibrous scaffolds were potential substitutes for artificial vascular scaffolds.


Assuntos
Prótese Vascular , Células Endoteliais/citologia , Metacrilatos/química , Polietilenoglicóis/química , Poliuretanos/química , Engenharia Tecidual/métodos , Alicerces Teciduais/química , Materiais Biocompatíveis/síntese química , Materiais Biocompatíveis/química , Fenômenos Biomecânicos , Adesão Celular , Proliferação de Células , Sobrevivência Celular , Reagentes de Ligações Cruzadas , Células Endoteliais/fisiologia , Células Endoteliais da Veia Umbilical Humana , Humanos , Interações Hidrofóbicas e Hidrofílicas , Teste de Materiais , Metacrilatos/síntese química , Microscopia Eletrônica de Varredura , Nanofibras/química , Nanofibras/ultraestrutura , Processos Fotoquímicos , Polietilenoglicóis/síntese química , Poliuretanos/síntese química
13.
ACS Sustain Chem Eng ; 10(42): 14001-14010, 2022 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-36312454

RESUMO

Transmission of viruses through contact with contaminated surfaces is an important pathway for the spread of infections. Antiviral surface coatings are useful to minimize such risks. Current state-of-the-art approaches toward antiviral surface coatings either involve metal-based materials or complex synthetic polymers. These approaches, however, even if successful, will have to face great challenges when it comes to large-scale applications and their environmental sustainability. Here, an antiviral surface coating was prepared by spin-coating lignin, a natural biomass residue of the paper production industry. We show effective inactivation of herpes simplex virus type 2 (>99% after 30 min) on a surface coating that is low-cost and environmentally sustainable. The antiviral mechanism of the lignin surface was investigated and is attributed to reactive oxygen species generated upon oxidation of lignin phenols. This mechanism does not consume the surface coating (as opposed to the release of a specific antiviral agent) and does not require regeneration. The coating is stable in ambient conditions, as demonstrated in a 6 month aging study that did not reveal any decrease in antiviral activity. This research suggests that natural compounds may be used for the development of affordable and sustainable antiviral coatings.

14.
PeerJ ; 9: e12601, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34993020

RESUMO

Wheat root rot disease due to soil-borne fungal pathogens leads to tremendous yield losses worth billions of dollars worldwide every year. It is very important to study the relationship between rhizosphere soil fungal diversity and wheat roots to understand the occurrence and development of wheat root rot disease. A significant difference in fungal diversity was observed in the rhizosphere soil of healthy and diseased wheat roots in the heading stage, but the trend was the opposite in the filling stage. The abundance of most genera with high richness decreased significantly from the heading to the filling stage in the diseased groups; the richness of approximately one-third of all genera remained unchanged, and only a few low-richness genera, such as Fusarium and Ceratobasidium, had a very significant increase from the heading to the filling stage. In the healthy groups, the abundance of most genera increased significantly from the heading to filling stage; the abundance of some genera did not change markedly, or the abundance of very few genera increased significantly. Physical and chemical soil indicators showed that low soil pH and density, increases in ammonium nitrogen, nitrate nitrogen and total nitrogen contributed to the occurrence of wheat root rot disease. Our results revealed that in the early stages of disease, highly diverse rhizosphere soil fungi and a complex community structure can easily cause wheat root rot disease. The existence of pathogenic fungi is a necessary condition for wheat root rot disease, but the richness of pathogenic fungi is not necessarily important. The increases in ammonium nitrogen, nitrate nitrogen and total nitrogen contributed to the occurrence of wheat root rot disease. Low soil pH and soil density are beneficial to the occurrence of wheat root rot disease.

15.
Huan Jing Ke Xue ; 41(6): 2698-2705, 2020 Jun 08.
Artigo em Zh | MEDLINE | ID: mdl-32608785

RESUMO

The micro-environment formed by the photosynthesis of submerged plants is conducive to the formation of CaCO3-P from co-precipitation of calcium and phosphorus in water, thereby permanently removing phosphorus from water to the bottom mud and avoiding secondary pollution after plants decay. However, CaCO3-P co-precipitation shows obvious specific-differences and environmental dependencies. In the present study, two different submerged plants, Myriophyllum aquaticum and Potamogeton crispus, were used as the research objects. Two variables, inorganic phosphorus level (0, 0.2, and 2 mg·L-1) and light intensity [66 µmol·(m2·s)-1 and 110 µmol·(m2·s)-1], were set. After cultivating for a week, the plant relative growth rate, plant total phosphorus, plant ash phosphorus, and Ca-P were measured to analyze the actual ability of phosphorus accumulation and clarify the effect of plant corruption on phosphorus increase in the water body. Results revealed that under various culture conditions, the relative growth rates (RGR) of P. crispus were significantly higher than those of M. aquaticum, and RGR reached the maximum at a P level of 2 mg·L-1 and a light intensity of 66 µmol·(m2·s)-1. The addition of inorganic phosphorus significantly affected plant ash phosphorus of the two plants (P. crispus 95.681%, M. aquaticum 85.432%), and the highest value of Ca-P content in the ash phosphorus of the two submerged plants appeared at a high phosphorus level. The total phosphorus in P. crispus was lower than that in M. aquaticum under various treatments, but the total ash phosphorus and Ca-P levels were higher than those in M. aquaticum. Consequently, M. aquaticum and P. crispus can effectively accumulate phosphorus during growth. However, the actual ability of P. crispus of removing phosphorus from water by the formation of CaCO3-P was higher than that of M. aquaticum at a P level of 2 mg·L-1.


Assuntos
Fósforo , Potamogetonaceae , Luz , Nitrogênio , Saxifragales
16.
RSC Adv ; 9(4): 2042-2054, 2019 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-35516149

RESUMO

Here, we selected macromolecular polyallylamine (PAH) as the monomer in an aqueous-phase reaction for the first time, which underwent interfacial polymerization with 1,3-benzenedisulfonyl chloride (BDSC) on the surface of a polyethersulfone (PES) ultrafiltration membrane to prepare a new PSA composite membrane with positive charge, acid stability and high separation performance. By tailoring the polymerization conditions, the desired PSA composite membrane exhibited excellent rejection of different salts [MgCl2 (92.44%) > MgSO4 (89.2%) > NaCl (56.8%) > Na2SO4 (55.2%)] and a high permeation flux of up to 34.10 L m-2 h-1 at 0.5 MPa. The properties of the membrane were evaluated using various characterization techniques. The results indicated that the new PSA membrane is more positively charged and more compact than reported PSA composite membranes. In addition, it exhibited high acid stability. After exposure to a 20% (w/v) H2SO4 solution for 30 days, the MgCl2 rejection level reached 88.3%. Finally, we used the new PSA composite membrane to test some heavy metal ions and found that the rejection level was always greater than 90%. Therefore, the new PSA composite membrane exhibited potential for water desalination and the removal of heavy metal ions from an acidic environment.

17.
Chemosphere ; 63(9): 1459-65, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16289224

RESUMO

In order to evaluate risk spreading among clones and antioxidant defence response of clonal ramets, turions of Vallisneria spinulosa, the dominant clonal plant of the submerged plant community in most of the lakes in Middle and Lower Reaches of Yangtze Rive, China, were planted in the heterogeneous soils contaminated with 40 and 160 microg g(-1) Pb (dry weight) in a greenhouse. After 100 d, the ranking order of tissue Pb concentrations in organs of the ortets (parental plants) was root>turion>rhizome>leaf, but that of tissue Pb quantities was leaf>turion>rhizome>root, due to their different biomass. Some of Pb was transferred from the ortets exposed in the Pb-supplied soil to leaves of the offspring growing in the favorable patch through rhizome (connective organ). A high foliar Pb concentration induced a significant decrease in superoxide dismutases, peroxidase and catalase activities. Catalase was more sensitive to Pb than the other two antioxidant enzymes. However, a low foliar Pb concentration, in the ortets exposed to 40 microg g(-1) Pb and in all of the offspring, slightly increased the activities of superoxide dismutases and peroxidase. The biomass accumulation per ortet and the biomasses percentages allocation to the roots and the leaves in Pb treatments decreased markedly. Nevertheless, there was no significant difference in biomass accumulation of the offspring between the low Pb level treatment and the control. The biomass percentage allocated to the root of the offspring was found to be larger than that of the ortets.


Assuntos
Chumbo/toxicidade , Magnoliopsida/fisiologia , Poluentes do Solo/toxicidade , Adaptação Fisiológica , Antioxidantes/metabolismo , Biomassa , Catalase/efeitos dos fármacos , Catalase/metabolismo , China , Chumbo/metabolismo , Magnoliopsida/efeitos dos fármacos , Malondialdeído/metabolismo , Peroxidase/efeitos dos fármacos , Peroxidase/metabolismo , Superóxido Dismutase/efeitos dos fármacos , Superóxido Dismutase/metabolismo , Superóxidos/metabolismo
18.
Chemosphere ; 93(2): 373-9, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23755986

RESUMO

Increased ammonium (NH4-N) concentrations in water bodies have been reported to adversely affect the dominant species of submersed vegetation in meso-eutrophic waters worldwide. However calcareous plants were lowly sensitive to NH4-N toxicity. In order to make clear the function of calcification in the tolerance of calcareous plants to NH4-N stress, we studied the effects of increased HCO3(-) and additional NH4-N on calcification and utilization of dissolve inorganic carbon (DIC) in Chara vulgaris Linn in a 7-d sub-acute experiment (light:dark 12:12h) carried out in an open experimental system in lab. Results revealed that calcification was dependent of utilization of dissolve inorganic carbon. Additional HCO3(-) significantly decreased the increase of pH while additional NH4-N did not. And additional HCO3(-) significantly improved calcification while NH4-N did in versus in relation to the variation of DIC concentration. However, addition of both HCO3(-) and NH4-N increased utilization of DIC. This resulted in calcification to utilization of DIC ratio decreased under additional NH4-N condition while increased under additional HCO3(-) conditions in response to the variation of solution pH. In the present study, external HCO3(-) decreased the increase of solution pH by increasing calcification, which correspondingly mitigated the toxic effect of high NH4-N. And we argue that the mitigating effect of increased HCO3(-) on NH4-N toxicity is dependent of plant calcification, and it is a positive feedback mechanism, potentially leading to the dominance of calcareous plants in meso-eutrophic water bodies.


Assuntos
Compostos de Amônio/toxicidade , Cálcio/metabolismo , Carbono/metabolismo , Chara/efeitos dos fármacos , Chara/metabolismo , Bicarbonatos/farmacologia , Chara/fisiologia , Concentração de Íons de Hidrogênio , Estresse Fisiológico/efeitos dos fármacos
19.
J Agric Food Chem ; 61(50): 12232-7, 2013 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-24308285

RESUMO

A thermoresponsive release multi-element compound fertilizer was first reported on the basis of a polydopamine-graft-poly(N-isopropylacrylamide) bilayer coated on a salty core by a combination of dopamine chemistry and surface-initiated atom transfer radical polymerization techniques, and the control of nutrient release in response to the environmental temperature was investigated. The successful synthesized stimuli-responsive fertilizers were confirmed by transmission electron microscopy (TEM), Fourier transforms infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and gel permeation chromatography (GPC). The release of elements from fertilizer was determined by an inductively coupled plasma (ICP) emission spectrometer. The thermosensitive fertilizers exhibit outstanding stimuli-responsive permeability to encapsulated nutrients, and the release rate of coated elements can be tailored by the ambient temperature. They can release nutrients easily at T < lower critical solution temperature (LCST) but slow at T > LCST. This strategy of grafting thermoresponsive polymer brushes on polydopamine (Pdop)-coated substrates is useful to prepare a stimuli-responsive release system, which can adjust the release rate according to different conditions, and will be effective and promising in the research and development of a stimuli-sensitive controlled-release system.


Assuntos
Resinas Acrílicas/química , Preparações de Ação Retardada/química , Fertilizantes/análise , Indóis/química , Polímeros/química , Animais , Bivalves/química , Cinética , Polimerização , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura
20.
J Agric Food Chem ; 61(12): 2919-24, 2013 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-23464683

RESUMO

This work reports on a facile and reliable method to prepare a polydopamine film coated controlled-release multielement compound fertilizer (PCMCF) based on mussel-inspired chemistry for the first time. The polydopamine (Pdop) film was coated on double copper potassium pyrophosphate trihydrate, providing three essential nutrients (Cu, K, and P) by spontaneous oxidative polymerization of dopamine. The thickness of the polymer coating of the fertilizer was controlled by using the multistep deposition technique. The morphology and composition of the products were characterized by transmission electron microscopy, inductively coupled plasma emission spectrometer, a vis spectrophotometer, and a Kjeltec autoanalyzer. The controlled-release behavior of four elements, including nitrogen from Pdop, was evaluated in water and in soil (sterilized or not). The results revealed that the coated fertilizers had good slow-release properties, incubated in either water or soil. It is noted that the release rate of nutrients of PCMCF can be tailored by the thickness of the Pdop coating, and the Pdop coating can be biodegraded in soil. This coating technology will be effective and promising in the research and development of controlled-release fertilizer.


Assuntos
Bivalves/química , Fertilizantes/análise , Indóis , Polímeros , Animais , Cobre , Preparações de Ação Retardada , Microscopia Eletrônica de Transmissão , Oxirredução , Fósforo , Polímeros/química , Potássio , Solo/química , Água/química
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