Potentiation of the Cytotoxic Activity of Copper by Polyphosphate on Biofilm-Producing Bacteria: A Bioinspired Approach

Adhesion and accumulation of organic molecules represent an ecologically and economically massive problem. Adhesion of organic molecules is followed by microorganisms, unicellular organisms and plants together with their secreted soluble and structure-associated byproducts, which damage unprotected surfaces of submerged marine structures, including ship hulls and heat exchangers of power plants. This is termed biofouling. The search for less toxic anti-biofilm strategies has intensified since the ban of efficient and cost-effective anti-fouling paints, enriched with the organotin compound tributyltin, not least because of our finding of the ubiquitous toxic/pro-apoptotic effects displayed by this compound [1]. Our proposed bio-inspired approach for controlling, suppressing and interfluencing the dynamic biofouling complex uses copper as one component in an alternative anti-fouling system. In order to avoid and overcome the potential resistance against copper acquired by microorganisms we are using the biopolymer polyphosphate (polyP) as a further component. Prior to being functionally active, polyP has to be hydrolyzed to ortho-phosphate which in turn can bind to copper and export the toxic compound out of the cell. It is shown here that inhibition of the hydrolysis of polyP by the bisphosphonate DMDP strongly increases the toxic effect of copper towards the biofilm-producing Streptococcus mutans in a synergistic manner. This bisphosphonate not only increases the copper-caused inhibition of cell growth but also of biofilm production by the bacteria. The defensin-related ASABF, a marine toxin produced by the sponge Suberites domuncula, caused only an additive inhibitory effect in combination with copper. We conclude that the new strategy, described here, has a superior anti-biofilm potential and can be considered as a novel principle for developing bio-inspired antifouling compounds, or cocktails of different compounds, in the future.     

用于测定黑茶中铅的荧光增强化学传感器

铅(Ⅱ)对固定在增塑的聚氯乙烯(PVC)敏感膜中的红霉素A有可逆荧光增强作用,据此研制了测定铅(Ⅱ)的荧光化学传感器。该传感膜的组成为:50.0 mg PVC、100.0 mg邻苯二甲酸二异辛酯和2.94 mg红霉素A。该传感器在pH 8.0的Tris-HCl缓冲溶液中,测定铅(Ⅱ)的动力学范围为4.00~6.00 mmol·L~(-1),检出限为0.10μmol·L~(-1),响应时间小于50 s。该传感器具有良好的重现性、可逆性和选择性,除Cr_2O_7~(2-)和MnO_4~-外,常见阴离子和阳离子不干扰测定。该传感器应用于黑茶水样中铅(Ⅱ)含量的测定,结果与GB 5009.12—2010法一致。     

Influence of water hardness on acid dyeing with silk

In this paper, the effect of water hardness, expressed in CaCO₃ equivalent, on the dyeing silk with acid dye under acid, alkaline and isoelectric point dyeing conditions was studied by zeta potential method. Under acid condition and in the presence of calcium ion, the positive zeta potential of silk was found to decrease with a reduction in the dye adsorption. Such a phenomenon might be due to the presence of cation which increased the dyeing potential barrier at the interface between fibre and dye solution. This would result in a higher resistance of dye anions passing through the interface. Under alkaline condition, the zeta potential on silk was negative and resulted in a strong potential barrier for the dye anions. The presence of calcium ion would result in a decrease in the absolute value of zeta potential of silk fibre with an overall increase in dye absorption. Under isoelectric point, the zeta potential of silk fibre was found to be near zero and dye adsorption was not influenced by the cations. When studying the effect of calcium ion on the silk dyeing with acid dye under acid, alkaline and isoelectric point dyeing conditions, it was found that calcium ions influenced dye exhaustion and fixation greatly under acidic and alkaline dyeing conditions, which such influence became much smaller when the pH of dyebath was at the isoelectric point of the fibre. These results showed that calcium ion could produce strong electrolytic effect on dyeing even under very low concentrations.     

A highly selective rhodamine based color turn on and fluorescence turn off sensor toward late IB metal ions

A fluorescence “turn-off” and color “turn-on” probe for late IB metal ions (Fe³⁺/Co²⁺/Ni²⁺/Cu²⁺/Zn²⁺) was developed based on rhodamine B. The probe was synthesized by condensation between rhodamine B and 8-hydroxyjulolidine-9-carboxaldehyde, which provided excellent selectivity function for late IB metal ions detection. It binds Cu²⁺ in a 1:1 stoichiometry in acetonitrile solution. This probe displays distinct color and fluorescence change upon the addition of late IB metal ions and little interference with other biologically relevant metal ions. Limit of detection for Cu²⁺, Fe³⁺, and Co²⁺ is higher than that of Zn²⁺ and Ni²⁺. In addition, the limit of detection toward Cu²⁺ is about 312 times lower than the World Health Organization (WHO) recommended level in drinking water.     

Colorimetric detection of transition metal ions with azopyridine-based probing molecule in aqueous solution and in PMMA film

We report on an azopyridine derivative for probing transition metal ions and fabrication of its films. The probe, AP, showed a sensitive absorption change toward transition metal ions, especially cobalt ion, even at the concentration of ppm range, accompanied by yellow-to-red color transition with noticeable isosbestic point. In addition, the AP-containing PMMA film with high transparency can be fabricated by spin-casting without any aggregation of AP. The film with PMMA matrix shows good sensitivity toward cobalt ion similar to the case in the solution with a feature of metallochromic transition.     

Synthesis and characterization of novel organo-soluble poly(ether-imide)s containing bulky moiety of triphenyl methane in the main chain

This paper describes the synthesis of novel thermally stable and organo-soluble poly(ether-imide)s (PEIs) by polycondensation reaction of a new synthesized diamine with different dianhydrides. Bis [4-(4-amino phenoxy)-2,5-dimethyl phenyl] paratolyl methane (6) as a new compound containing ether groups and bulky moiety of triphenyl methane was successfully prepared by a three step reaction. First, the diol compound (3) was prepared by a solvent free reaction of 2,5-dimethylphenol (1) with 4-methylbenzaldehyde (2). Then, the diol (3) was converted to dinitro (5) by reaction with 4-fluoronitrobenzene. Finally, dinitro (5) was reducted through the reaction with Pd/C 10 %. The structure of diamine (6) and resulting poly(ether-imide)s (8a-d) confirmed by ¹HNMR, FTIR spectroscopy and elemental analysis (CHN). Also the properties of poly(ether-imide)s (8a-d) were investigated by mean of thermal gravimetric analysis (TGA), differantial thermal gravimetric (DTG), differential scanning calorimetry (DSC), solubility tests and inherent viscosity. The resulted polymers show excellent thermal stability, good solubility in aprotic polar solvent and inherent viscosities between 0.37-0.50 dl/g.     

Detector for rapid detection of trace Cu<Superscript>2+</Superscript> in paddy water based on dual-wavelength quantum dot fluorescent probe

A novel device is designed for rapid detection of trace Cu²⁺ residues in paddy water using dual-wavelength quantum dot fluorescence probe. It includes three operation procedures: synthesis of dual-wavelength quantum dot, fluorescence excitation and acquisition of weak signal and signal conditioning. Based on the quenching principle of Cu²⁺ on quantum dot fluorescence, dual-wavelength quantum dot fluorescent probe can get lower limitation of detection. In addition, to improve the accuracy of testing results, two-channel detection was developed for avoiding interference. Experiment results demonstrate that the limitation for detection of trace Cu²⁺ in paddy water is 1.4 nM. The relationship between the Cu²⁺ concentration (x) and the ratio variation of dual wavelength (y) is y?=?2.15?×?exp(x/5.862)???1.154 with the coefficient of determination (R²) of 0.997 and the detection time of 4 min. Meanwhile, compared to other heavy metal ions, nutrient and organic compounds, the presented detector is of good selectivity for Cu²⁺ in paddy water. The repetitive detection experiments show that the developed device has high repeatability with relative standard deviation of 0.14%. The device can be used for quick and accurate detection of trace Cu²⁺ residues in paddy water with some specific advantages of high sensitivity, excellent selectivity and high repeatability.     

Electrical Resistivity of Plasma Treated Viscose and Cotton Fabrics with Incorporated Metal Ions

Cellulose fabrics (viscose and cotton) were treated with atmospheric pressure dielectric barrier discharge (DBD) in air. After DBD treatment, samples were characterized and volume electrical resistance was measured under different relative humidity conditions (φ=40-55 %). Results have shown that DBD treatment increases wettability and polar surface functional groups content, which consequently causes a decrease of volume electrical resistivity of cellulose fabrics in measured relative humidity range (φ=40-55 %). Metal ions (silver, copper, and zinc) were incorporated in untreated and plasma treated samples through sorption from aqueous solutions and incorporation of metal ions into plasma treated cellulose samples decreased electrical resistivity even further. Resistivity of cotton and viscose fabrics with incorporated metal ions followed the order Zn²⁺ > Cu²⁺ > Ag⁺. The most pronounced decrease, for entire order of a magnitude, was obtained by modification of cotton fabric with DBD and silver ions, where value of resistivity dropped from GΩ to a several dozens of MΩ.     

低温对杂交水稻及其亲本剑叶77K荧光的影响

 以大田栽培的三套杂交水稻组合汕优63、青优早和秀优57为材料， 研究了低温(5℃)与光照(210 μmol m^-2 s^-1 PFD)对杂交水稻F₁及其亲本剑叶77K荧光的影响。结果表明：低温引起77K荧光参数F0、Fm、Fv下降，可变荧光Fv的变化能反映三套杂交水稻组合间的抗冷性的差异。F₁的抗冷性居父母本之间。同时发现，在低光照下低温处理引起Fo，Fm，Fv上升，但未改变Fv／Fm，Fv／Fo的比值。证明在低温下，低于水稻生长光强210μmol m^-2 s^-1 PFD的光照对PSⅡ的最初光能转化效率和光能传递速率影响不大， 即对光合作用的光化学过程未产生光抑制现象。由此可见，取样于田间强光照下的水稻剑叶，在5℃和210μmol m^-2 s^-1 PFD 处理下，210μmol m^-2 s^-1 PFD可能有利于水稻对低温的适应， 从而减轻叶片的光化学过程的伤害程度。     

Cyclopeptide Derivatives from the Sponge-Derived Fungus Acremonium persicinum F10

Cyclopeptides usually play a pivotal role, either in the viability or virulence of fungi. Two types of cyclopeptides, six new hydroxamate siderophore cyclohexapeptides (1–6), including acremonpeptides E and F, and their complexes with aluminum and ferric ions; one new cyclic pentapeptolide, aselacin D (9); together with a known compound, aselacin C (10), were isolated and characterized from the sponge-derived fungus Acremonium persicinum F10. In addition, two new siderophore analogues chelating gallium ions (Ga³⁺), Ga (III)-acremonpeptide E (7) and Ga (III)-acremonpeptide F (8), using isolated acremonpeptides E and F, were prepared. The planar structures of 1–10 were elucidated by HRESIMS and (1D and 2D) NMR. The absolute configurations of amino acids were determined by means of the advanced Marfey’s method and X-ray single-crystal diffraction analysis. X-ray fluorescence (XRF) spectrometer was performed to disclose the elements of compound 1, indicating the existence of aluminum (Al). Al (III)-acremonpeptides E (1), Ga (III)-acremonpeptides E (5), Al (III)-acremonpeptide F (7), and Ga (III)-acremonpeptide F (8) displayed high in vitro anti-fungal activities, which are comparable to amphotericin B, against Aspergillus fumigatus and Aspergillus niger.     

“稻—鳖—鱼”复合种养模式关键技术

"稻—鳖—鱼"复合种养模式具备良好的经济、社会、生态效益,是一种环境友好型的农业模式,能提高农民收入,有效降低农业面源污染,为人们提供绿色安全的食品.从稻田基础建设、"稻—鳖—鱼"复合种养技术、水稻种植技术等方面介绍"稻—鳖—鱼"复合种养技术要点,以供"稻—鳖—鱼"复合种养模式的推广.     

Dissolution and regeneration behavior of chitosan in 3-methyl-1-(ethylacetyl)imidazolium chloride

3-methyl-1-(ethylacetyl)imidazolium chloride ([EtMIM]Cl), was synthesized for chitosan dissolution, and the dissolution and regeneration behaviors of chitosan in [EtMIM]Cl were thoroughly investigated. The solubility of chitosan in [EtMIM]Cl was measured at temperatures ranging from 40 °C to 110 °C, based on which the thermodynamic parameters of chitosan in [EtMIM]Cl were calculated. The polarizability and hydrogen bond accepting ability was determined by solvatochromic UV/vis spectroscopy. The regenerated chitosan from [EtMIM]Cl by adding methanol was characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Density functional theory (DFT) computations were performed to study the interactions between [EtMIM]Cl and chitobiose. Five kinds of hydrogen bonds, C-H/O, O-H/O, O-H/Cl, C-H/Cl, N-H/Cl were found, suggesting strong interactions between [EtMIM]Cl and chitobiose. In particular, the oxygen atom and the active methylene group of carboxylic ester in [EtMIM]⁺, formed strong hydrogen bonding with chitobiose. The molecular simulation results indicated that both the Cl^? anions and [EtMIM]⁺ cation played important roles in the chitosan dissolution process, by the disruption of native hydrogen bonds of chitosan.     

Combined use of Multiple Methodologies for the Measurement of Total Antioxidant Capacity in UK Commercially Available Vegetable Juices

Substantial evidence exists to support the hypothesis that high fruit and vegetable consumption, rich in antioxidants, can reduce the incidence of several disease states. The aim of this study was to compare the results obtained by six spectrophotometric biochemical methods including the ferric reducing antioxidant power (FRAP), 2, 2-diphenyl-1-picryhydrazyl (DPPH?), 2,2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS??), copper (II) reducing capacity (CUPRAC) and Cerium (IV) reducing antioxidant capacity (CERAC) assays as well as Folin-Ciocalteu method (FC) for the measurement of total antioxidant capacity (TAC) and total polyphenols (TP) in different commercially available vegetable juices. There was a significant positive correlation between the results obtained for FRAP, ABTS??, CUPRAC, CERAC and FC (0.68?≤?r?≤?0.96, P?相似文献   

Whole blood cyanide levels of mainly dietary origin in a human population sample in Port Harcourt,Nigeria

Whole blood cyanide levels in a human population sample of volunteers known to each gari-based meals at least once a day were determined. The most widely eaten cassava product in the area of research is gari. The mean blood cyanide obtained for healthy normal volunteers was 0.294 ± 0.09 mol/L while the value for sicklers was 0.398±0.008 mol/L, indicating the possibility of reduced rate of metabolism and excretion of cyanide by sicklers as compared to non-sicklers.Investigation of post-absorption distribution indicated that whole blood cyanide increased by 0.014 mol/L, 3–4 hours after a gari-based meal in normal volunteers. A decrease of 0.012 mol/L occurred after a whole-rice meal. The increase in plasma cyanide 2–3 hours after a gari-based meal was about 25% more than the increase in erythrocyte cyanide suggesting a significant contribution of plasma cyanide to whole blood cyanide levels. 0.013–0.015 mg cyanide per kg of gari was determined for samples of this staple food in the locality of research.     

Ecological and Pharmacological Activities of Polybrominated Diphenyl Ethers (PBDEs) from the Indonesian Marine Sponge Lamellodysidea herbacea

Two known Polybrominated Diphenyl Ethers (PBDEs), 3,4,5-tribromo-2-(2′,4′-dibromophenoxy)phenol (1d) and 3,4,5,6-tetrabromo-2-(2′,4′-dibromophenoxy)phenol (2b), were isolated from the Indonesian marine sponge Lamellodysidea herbacea. The structure was confirmed using ¹³C chemical shift average deviation and was compared to the predicted structures and recorded chemical shifts in previous studies. We found a wide range of bioactivities from the organic crude extract, such as (1) a strong deterrence against the generalist pufferfish Canthigaster solandri, (2) potent inhibition against environmental and human pathogenic bacterial and fungal strains, and (3) the inhibition of the Hepatitis C Virus (HCV). The addition of a bromine atom into the A-ring of compound 2b resulted in higher fish feeding deterrence compared to compound 1d. On the contrary, compound 2b showed only more potent inhibition against the Gram-negative bacteria Rhodotorula glutinis (MIC 2.1 μg/mL), while compound 1d showed more powerful inhibition against the other human pathogenic bacteria and fungi. The first report of a chemical defense by compounds 1d and 2b against fish feeding and environmental relevant bacteria, especially pathogenic bacteria, might be one reason for the widespread occurrence of the shallow water sponge Lamellodysidea herbacea in Indonesia and the Indo-Pacific.     

遮光对光照敏感型新梢白化茶春梢化学成分含量的影响

以光照敏感型新梢白化茶树‘黄-2’、‘黄-8’和‘黄-13’为供试材料,在春季一芽一叶期采用30%透光度的黑色遮阳网覆盖遮光处理7天,HLPC法检测一芽二叶新梢咖啡因、儿茶素类、氨基酸类和色素类化合物含量。结果显示,遮光处理对茶叶咖啡因含量无显著影响;遮光对儿茶素类总含量的影响因品种而异,在品系‘黄-2’显著提高,而品系‘黄-8’和‘黄-13’则显著降低;遮光显著提高品系‘黄-13’的氨基酸总含量,降低品系‘黄-8’氨基酸总含量,但对品系‘黄-2’无显著影响;遮光显著提高β-胡萝卜素、叶绿素a、叶绿素b和新黄质的含量,显著降低紫黄质含量。具有热耗散作用的黄体素在光照敏感新梢白化茶品种的含量很低,是其容易受到强光胁迫伤害的原因。在强光照条件下,光照敏感型新梢白化茶叶片呈现黄色,主要是叶绿素含量显著降低,而不是因为胡萝卜素和叶黄素含量提高所致。根据这些研究结果,作者认为:在高温强光季节采取适度遮光,将有助于光照敏感型新梢白化茶提高叶片叶绿素含量,增强光合作用,进而提高茶苗生长势和抗性,有助于提高茶苗移栽成活率。     

An anion sensor based on calix[4]arene-Reichardt’s dye

A highly selective colorimetric displacement assay for anions, F⁻ and H₂PO₄ ⁻, based on calix[4]arene-Reichardt’s dye was studied in DMSO. When calix[4]arene forms a complex with Reichardt’s, the absorption peak at 386, 419 and 632 nm disappeared. Addition of anions to solution of calix[4]arene-Reichardt’s dye causes the blue color of Reichardt’s dye to return as it is displaced from the calix[4]arene. These results demonstrate that this displacement assay can be favorably utilized for the development of potential sensors for the detection of anion such as F⁻ and H₂PO₄ ⁻ in relation to the other anions.     

Additional Evidence of the Trypanocidal Action of (?)-Elatol on Amastigote Forms through the Involvement of Reactive Oxygen Species

Chagas’ disease, a vector-transmitted infectious disease, is caused by the protozoa parasite Trypanosoma cruzi. Drugs that are currently available for the treatment of this disease are unsatisfactory, making the search for new chemotherapeutic agents a priority. We recently described the trypanocidal action of (−)-elatol, extracted from the macroalga Laurencia dendroidea. However, nothing has been described about the mechanism of action of this compound on amastigotes that are involved in the chronic phase of Chagas’ disease. The goal of the present study was to evaluate the effect of (−)-elatol on the formation of superoxide anions (O₂^•−), DNA fragmentation, and autophagy in amastigotes of T. cruzi to elucidate the possible mechanism of the trypanocidal action of (−)-elatol. Treatment of the amastigotes with (−)-elatol increased the formation of O₂^•− at all concentrations of (−)-elatol assayed compared with untreated parasites. Increased fluorescence was observed in parasites treated with (−)-elatol, indicating DNA fragmentation and the formation of autophagic compartments. The results suggest that the trypanocidal action of (−)-elatol might involve the induction of the autophagic and apoptotic death pathways triggered by an imbalance of the parasite’s redox metabolism.     

The Chemically Synthesized Ageladine A-Derivative LysoGlow84 Stains Lysosomes in Viable Mammalian Brain Cells and Specific Structures in the Marine Flatworm Macrostomum lignano

Based on the chemical structure and the known chemical synthesis of the marine sponge alkaloid ageladine A, we synthesized the ageladine A-derivative 4-(naphthalene-2-yl)-1H-imidazo[4,5-c]pyridine trifluoroacetate (LysoGlow84). The two-step synthesis started with the Pictet-Spengler reaction of histamine and naphthalene-2-carbaldehyde to a tetrahydropyridine intermediate, which was dehydrogenated with activated manganese (IV) oxide to LysoGlow84. Structure and purity of the synthesized LysoGlow84 were confirmed by NMR spectroscopy and mass spectrometry. The fluorescence intensity emitted by LysoGlow84 depended strongly on the pH of the solvent with highest fluorescence intensity recorded at pH 4. The fluorescence maximum (at 315 nm excitation) was observed at 440 nm. Biocompatibility of LysoGlow84 was investigated using cultured rat brain astrocytes and the marine flatworm Macrostomum lignano. Exposure of the astrocytes for up to 6 h to micromolar concentrations of LysoGlow84 did not compromise cell viability, as demonstrated by several viability assays, but revealed a promising property of this compound for staining of cellular vesicles. Conventional fluorescence microscopy as well as confocal scanning microscopy of LysoGlow84-treated astrocytes revealed co-localization of LysoGlow84 fluorescence with that of LysoTracker^® Red DND-99. LysoGlow84 stained unclear structures in Macrostomum lignano, which were identified as lysosomes by co-staining with LysoTracker. Strong fluorescence staining by LysoGlow84 was further observed around the worms’ anterior gut and the female genital pore which were not counterstained by LysoTracker Red. Thus, LysoGlow84 is a new promising dye that stains lysosomes and other acidic compartments in cultured cells and in worms.     

Synthesis,characterization and aggregation and fluorescence properties of novel highly soluble zinc phthalocyanines bearing tetrakis-4-(3-(piperidin-1-yl)phenoxy) with tetra and dodecachloro substituents

The synthesis of two new phthalocyanine precursors 4-(3-(piperidin-1-yl)phenoxy) with mono (2) and trichloro (3) substituents were carried out in this work. Cyclotetramerization of these precursors with zinc acetate gave novel tetrakis-4-(3-(piperidin-1-yl)phenoxy) with tetra (4) and dodecachloro (5) substituted zinc phthalocyanines. The synthesized new compounds were characterized using FT-IR, ¹H NMR, electronic absorption spectroscopy, mass spectra and elemental analysis. The aggregation behavior of zinc phthalocyanines 4 and 5 was investigated in different concentrations of dichloromethane (DCM). Zinc phthalocyanines 4 and 5 showed good solubility in different organic solvents such as DCM, CHCl₃, THF, benzene and toluene. Further, the aggregation behavior of zinc phthalocyanines 4 and 5 was studied before and after the addition of Triton X100. Further, the fluorescence quantum yields of zinc phthalocyanines 4 and 5 were calculated in the presence and absence of Triton X100.