Synthesis and decoloring properties of sodium humate/poly (N-isopropylacrylamide) hydrogels

A series of novel sodium humate/poly(N-isopropylacrylamide) (SH/PNIPA) hydrogels were synthesized by solution polymerization. The swelling and decoloring properties of SH/PNIPA hydrogels were also examined. Experiment results show that there exist hydrogen-bonding interactions between SH and PNIPA in the SH/PNIPA hydrogels network, which are not strong enough to disrupt the aggregation of dehydrated PNIPA chains at phase transition temperature, leading to the same volume phase transition temperature as pure PNIPA hydrogel. The adsorption and desorption of methylene blue (MB) for the hydrogels were influenced by temperature, initial MB concentration and SH amount. Low temperature favors the adsorption and desorption of MB. Appropriate SH amount of the hydrogels is crucial for the adsorption and desorption of MB. The maximum adsorption capacity was 10.8 mg MB per gram of SH/PNIPA gel.     

New platinum-oxicam complexes as anti-cancer drugs. Synthesis, characterization, release studies from smart hydrogels, evaluation of reactivity with selected proteins and cytotoxic activity in vitro

The reaction of aqueous cis-[Pt(NH₃)₂(H₂O)₂](NO₃)₂ with Na⁺HMEL⁻ (H₂MEL, meloxicam, 4-hydroxy-2-methyl-N-(5-methyl-1,3-thiazol-2-yl)-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide), and Na⁺HISO⁻ (H₂ISO, isoxicam, 4-hydroxy-2-methyl-N-(5-methylisoxazol-3-yl)-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide) at pH 7 produced micro-crystalline cis-[Pt(NH₃)₂(N^1′-HMEL)₂], 5 and cis-[Pt(NH₃)₂(N^1′-HISO)₂], 6. The X-ray diffraction structure of 5 shows two HMEL⁻ anions donating through the thiazole nitrogen atoms and adopting a head-to-tail (HT) conformation. The ¹H NMR spectrum for 5 from DMSO-d₆ shows inertness of the complex up to at least 24 h. Delivery studies for 5 and 6 from vinyl hydrogel based on l-phenylalanine (pH 6.5, 25 °C) show that concentrations of complexes ranging between 2.5 and 5 μM can be reached after a day. Compounds 5 and 6 show strong anti-proliferative effects on CH1 cells (ovarian carcinoma, human) in vitro, IC₅₀ values being 0.60 and 0.37 μM, respectively (0.16 μM for reference, cis-diamminodichloridoplatinum(II), cisplatin). ESI-MS measurements clearly documented that both 5 and 6 form adducts with the three model proteins ubiquitin (UBI), cytochrome c (CYT C) and superoxide dismutase (SOD), the HISO⁻ complex being significantly more effective than the HMEL⁻ one. Density functional methods help in finding rationale for the easiest dissociation of Pt-H₂ISO/HISO bonds when compared to the Pt-N^1′-H₂MEL/N^1′-HMEL linkages.     

Matrix-assisted ultraviolet laser-desorption ionization and electrospray-ionization time-of-flight mass spectrometry of sulfated neocarrabiose oligosaccharides

Several commercial sulfated neocarrabiose oligosaccharides were analyzed by matrix-assisted ultraviolet laser-desorption ionization time-of-flight mass spectrometry (UV-MALDI-TOF-MS). UV-MALDI-TOF-MS was carried out in the linear and reflectron modes and, as routine, in both the positive- and negative-ion modes. 2,5-Dihydroxybenzoic acid and nor-harmane were used as matrices. In the positive- and negative-ion modes, with both matrices, peaks corresponding to (M+Na)(+) and (M-Na)(-) ions, respectively, were obtained, with only some signals due to glycosidic linkage cleavages (prompt fragmentation). With 2,5-dihydroxybenzoic acid abundant matrix signals were observed; nor-harmane afforded very few matrix signals in both ion modes, but more desulfation (prompt fragmentation) of the compounds occurred. When the desorption/ionization process was highly efficient, the post-source decay (PSD) fragmentation patterns were also investigated; most of the fragments detected derived from glycosidic linkage cleavages. Electrospray-ionization time-of-flight mass spectrometry (ESI-TOF-MS) in the negative-ion mode confirmed, with the observation of the (M-Na)(-) and the multiply charged anions, the identity and the purity of the samples.     

Blocking nonspecific adsorption of native food-borne microorganisms by immunomagnetic beads with iota-carrageenan

We present herein the partitioning characteristics of anti-Salmonella and anti-Escherichia coli O157 immunomagnetic beads (IMB) with respect to the nonspecific adsorption of several nontarget food-borne organisms with and without an assortment of well-known blocking agents, such as casein, which have been shown to be useful in other immunochemical applications. We found several common food-borne organisms that strongly interacted with both types of IMB, especially with anti-Salmonella form (av DeltaG0=-20 +/- 4 kJ mol(-1)) even in the presence of casein [1% (w/v): DeltaG0=-18 +/- 3 kJ mol(-1); DeltaDeltaG0 approximately -2 kJ mol(-1)]. However, when one of the most problematic organisms (a native K12-like E. coli isolate; DeltaG0=-19 +/- 2 kJ mol(-1)) was tested for nonspecific binding in the presence of iota-carrageenan (0.03-0.05%), there was an average decline of ca. 90% in the equilibrium capture efficiency xi (DeltaG0=-11 +/- 4 kJ mol(-1); DeltaDeltaG0 approximately -8 kJ mol(-1)). Other anionic polysaccharides (0.1% kappa-carrageenan and polygalacturonic acid) had no significant effect (av DeltaG0=-19 +/- 1 kJ mol(-1); DeltaDeltaG0 approximately 0 kJ mol(-1)). Varying iota-carrageenan from 0% to 0.02% resulted in xi significantly diminishing from 0.69 (e.g., 69% of the cells captured; DeltaG0=-19 +/- 3 kJ mol(-1)) to 0.05 (DeltaG0=-11 +/- 2 kJ mol(-1); DeltaDeltaG0 approximately -9 kJ mol(-1)) at about 0.03% iota-carrageenan where xi leveled off. An optimum blocking ability was achieved with 0.04% iota-carrageenan suspended in 100 mM phosphate buffer. We also demonstrated that the utilization of iota-carrageenan as a blocking agent causes no great loss in the IMBs capture efficiency with respect to the capture of its target organisms, various salmonellae.     

Role of extracellular polymeric substances in Cu(II) adsorption on Bacillus subtilis and Pseudomonas putida

The effect of extracellular polymeric substances (EPS) of Gram-positive Bacillus subtilis and Gram-negative Pseudomonas putida on Cu(II) adsorption was investigated using a combination of batch adsorption, potentiometric titrations, Fourier transform infrared spectroscopy. Both the potentiometric titrations and the Cu(II) adsorption experiments indicated that the presence of EPS in a biomass sample significantly enhance Cu(II) adsorption capacity. Surface complexation modeling showed that the pK_a values for the three functional groups (carboxyl, phosphate and hydroxyl) were very similar for untreated and EPS-free cells, indicating no qualitative difference in composition. However, site concentrations on the untreated cell surface were found to be significantly higher than those on the EPS-free cell surface. Infrared analysis provided supporting evidence and demonstrated that carboxyl and phosphate groups are responsible for Cu(II) adsorption on the native and EPS-free cells.     

使用透明质酸钠复合海藻酸钠水凝胶球3D培养软骨细胞抑制细胞去分化的研究

目的:验证海藻酸钠(Alginate,Alg)水凝胶球添加透明质酸钠(Sodium hyaluronate,HA)后,对大鼠膝软骨细胞体外3D培养时软骨细胞去分化的抑制情况。方法:用Ⅱ型胶原酶消化法获取2周龄SD大鼠膝关节原代软骨细胞,体外培养传代至P2。细胞分为2组,1组用2%海藻酸钠水凝胶球3D培养(Alg组),另一组用2%海藻酸钠+1%透明质酸钠的水凝胶球3D培养(Alg/HA组),采用正交法制作海藻酸钠水凝胶球。培养14天后,两组各取水凝胶球进行死活细胞染色观察细胞状态。其他水凝胶球收集后用4%多聚甲醛固定,30%蔗糖溶液脱水,OCT(Optimal cutting temperature compound)包埋剂包埋切片,采用苏木精-伊红染色法(Hematoxylin-eosin staining,HE染色)、甲苯胺蓝染色观察软骨细胞形态;采用阿利新蓝染色观察对比糖胺聚糖(Glycosaminoglycan,GAG)含量;采用免疫荧光染色对比Ⅱ型胶原(Collagen typeⅡ,ColⅡ)含量;采用蛋白质免疫印迹法(Western blot)检测软骨细胞ColⅡ和聚蛋白多糖(Aggrecan,ACAN)的表达情况。结果:死活细胞染色显示两组水凝球内软骨细胞状态良好,几乎无死细胞;阿利新蓝染色显示Alg/HA组与Alg组相比软骨细胞分泌更多的GAG;免疫荧光染色显示Alg/HA组比Alg组软骨细胞内含更多的Ⅱ型胶原;Western blot显示Alg/HA组软骨细胞比Alg组ColⅡ的蛋白表达更多。结论:含透明质酸钠的海藻酸钠水凝胶可以更好地维持软骨细胞的表型,抑制软骨细胞去分化。     

Waste biomass of Nostoc linckia as adsorbent of crystal violet dye: Optimization based on statistical model

The potential of spent biomass of a hydrogen producing cyanobacterial strain Nostoc linckia from a hydrogen fermentor was studied for decolorization of a tri-phenylmethane dye, crystal violet. The waste cyanobacterial biomass immobilized in calcium alginate was used as a biosorbent and the process variables were optimized for maximum dye removal using the statistical response surface methodology (RSM). Batch mode experiments were performed to determine the kinetic behavior of the dye in aqueous solution allowing the computation of kinetic parameters. Influence of interacting parameters like temperature (25-35 °C), pH (4-8), initial dye concentration (100-200 mg/L) and cyanobacterial dose (0.2-0.4 g) on dye removal were examined using central composite design (CCD) which included two additional levels for each parameter. Second-order polynomial regression model, was applied which was statistically validated using analysis of variance. Ability of the immobilized biomass to decolorize the dye was maximum (72%) at pH 8.0, temperature 35 °C, 200 mg/L initial dye concentration and 0.2 g cyanobacterial dose. Adsorption of the dye on cell surface was further confirmed by scanning electron micrographs of the biomass before and after dye loading. FT-IR studies revealed that decolorization was due to biosorption mediated mainly by functional groups like hydroxyl, amide, carboxylate, methyl and methylene groups present on the cell surface.     

Biodegradation of crystal violet by Pseudomonas putida

Crystal violet (CV), which has been extensively used as a biological stain and a commercial textile dye, is a recalcitrant molecule. A strain of Pseudomonas putida was isolated that effectively degraded CV: up to 80% of 60 μM CV as the sole carbon source, was degraded in liquid media within 1 week. Nine degradation products were isolated and identified. We propose that CV degradation occurs via a stepwise demethylation process to yield mono-, di-, tri-, tetra-, penta- and hexa-demethylated CV species.     

New cationic palladium(II) compounds with several bidentate nitrogen-donor ligands: Synthesis, spectroscopic analyses and X-ray crystal structure

A series of PdN₄core complexes has been synthesised. Reaction of [PdCl₂(CH₃CN)₂] with N-alkylaminopyrazole (NN′) ligands, 1-[2-(ethylamino)ethyl]-3,5-dimethylpyrazole (deae), 1-[2-(ⁱpropylamino)ethyl]-3,5-dimethylpyrazole (deai), and 1-[2-(^tbutylamino)ethyl]-3,5-dimethylpyrazole (deat) in the presence of AgBF₄ led to [Pd(NN′)₂](BF₄)₂. These palladium(II) compounds were characterised by elemental analyses, conductivity measurements, IR, ¹H and ¹³C{¹H} NMR spectroscopies. The NMR studies of the complexes prove the rigid conformation of the ligands when they are complexed. The X-ray analyses of one representative complex, [Pd(deat)₂](BF₄)₂, is reported. The crystal structure consists of discrete centrosymmetric cations involving a coordinated Pd(N_pz)₂(N_amino)₂core with planar geometry and anions.     

Biosorption of phenol and 2-chlorophenol by Funaliatrogii pellets

The removal of phenol (Ph) and 2-chlorophenol (2-CPh) from aqueous solution by native and heat inactivated fungus Funaliatrogii pellets were investigated. The effects of contact time, solid/liquid ratio, optimum pH and temperature on the phenols removal capacity by the pellets were established. The removal efficiency of phenols increased significantly with increasing biomass dose. The optimum pH was detected to be 8.0. The second-order equations are described and evaluated on the basis of a comparative estimation of the corresponding coefficients. The phenol removal equilibrium isotherm was modeled by the Langmuir equations. The enthalpy change values were obtained between −7.62 and −10.64 kJ/mol. This indicated that the uptake of phenols either on native or heat inactivated fungal pellets was based on a physical adsorption process.     

Synthesis, crystal structure and luminescent behaviour of coordination complexes of copper with bi- and tridentate amines and phosphonic acids

The synthesis and crystal structure of four new copper(I) and copper(II) supramolecular amine, and amine phosphonate, complexes is reported. Reaction of copper(I) with 2-,9-dimethyl-1-10-phenanthroline (dmp) produced a stable 4-coordinate Cu(I) species, [Cu^(I)(dmp)₂]Cl · MeOH · 5H₂O (2), i.e., the increased steric hindrance in the ‘bite’ area of dmp did not prevent interaction with the metal and provided protection against oxidation which was not possible for the phen analogue [R. Clarke, K. Latham, C. Rix, M. Hobday, J. White, CrystEngCommun. 7(3) (2005), 28-36]. Subsequent addition of phenylphosphonic acid to (2) produced two structures from alternative synthetic routes. An ‘in situ’ process yielded red block Cu(I) crystals, [Cu^(I)(dmp)₂] · [C₆H₅PO₃H₂ · C₆H₅PO₃H] (4), whilst recrystallisation of (2) prior to addition of the acid (‘stepwise’ process) produced a green, needle-like Cu(II) complex, [Cu^(II)(dmp) · (H₂O)₂ · C₆H₅PO₂(OH)] [C₆H₅PO₂(OH)] (3). However, addition of excess dmp during the ‘stepwise’ process forced the equilibrium towards product (4) and resulted in an optimum yield (99%). The structure of (4) was similar to the phen analogue, [Cu^(II)Cl(phen)₂] · [C₆H₅PO₂(OH) · C₆H₅PO(OH)₂] (1) [R. Clarke, K. Latham, C. Rix, M. Hobday, J. White, CrystEngCommun. 7(3) (2005), 28-36], but the presence of dmp exerted some influence on global packing, whilst (3) exists as a polymeric layered material. In contrast, reaction of copper(I) with di-2-pyridyl ketone (dpk), followed by phenylphosphonic acid produced purple/blue Cu(II) species, [Cu^(II)(dpk · H₂O)₂] Cl₂ · 4H₂O (5), and [Cu^(II)(dpk · H₂O)₂] · [C₆H₅PO₂(OH)₂ · C₆H₅PO(OH)₂] (6), respectively, i.e., in both cases oxidation of copper occurred. Solid-state luminescence was observed in (2) and (4). The latter showing a 5-fold enhancement in intensity.     

Synthesis, structures and in vitro cytotoxicity of some cationic cis-platinum(II) complexes containing chelating thiocarbamates

The thiocarbamates 4-RC₆H₄NHC(S)NR₂′ (R = H, Cl; R′ = Me, Et), 4-ClC₆H₄NHC(S)NR (NR = 2-pyridylpiperazine) react with cis-[PtCl₂(PTA)₂] (PTA = 1,3,5-triaza-7-phosphaadamantane) in the presence of base to afford the monocationic platinum(II) complexes cis-[Pt{SC(NR₂′) = NC₆H₄R}(PTA)₂]⁺ (R = H, Cl; R′ = Me, Et), cis-[Pt{SC(NR) = NC₆H₄Cl}(PTA)₂]⁺ (NR = 2-pyridylpiperazine), which were isolated as their PF₆ salts in high yields. The complexes were fully characterised spectroscopically and also by X-ray crystallography. Cytotoxicity of these complexes was studied in vitro in three human cancer cell lines (CH1, A549 and SW480) using the MTT assay.     

Synthesis of some O-, S- and N-glycosides of hept-2-ulopyranosonamides

(O-Peracylated α-d-gluco- and -galacto-hept-2-ulopyranosylbromide)onamides gave the corresponding (alkyl β-d-glyco-hept-2-ulopyranoside)onamides under Koenigs-Knorr conditions, and similar aryl glycosides were obtained with sodium phenolates; (aryl and hetaryl 2-thio-β-d-gluco-hept-2-ulopyranoside)onamides were formed with thiophenols in the presence of K₂CO₃ in acetone, and reactions with aniline in CH₂Cl₂ furnished (N-phenyl β-d-glyco-hept-2-ulopyranosylamine)onamides. Some deprotected derivatives of d-gluco configuration obtained by the Zemplén protocol showed no significant inhibition against rabbit muscle glycogen phosphorylase b.     

Trypanosoma cruzi: Activity of heterocyclic cationic molecules in vitro

Chagas disease remains a serious public health problem in several Latin American countries. New chemotherapy is urgently needed since current drugs are limited in efficacy and exhibit undesirable side effects. Aromatic diamidines and analogs are well known anti-parasitic agents and in this study, we have evaluated the in vitro trypanocidal effect of several different heterocyclic cationic compounds, including diamidines (DB1195, DB1196 and DB1345), a monoamidine (DB824), an arylimidamide (DB613A) and a guanylhydrazone (DB1080) against amastigotes and bloodstream trypomastigotes of Trypanosoma cruzi, the etiological agent of Chagas disease. Our present findings showed that all compounds exerted, at low-micromolar doses, a trypanocidal effect upon both intracellular parasites and bloodstream trypomastigotes of T. cruzi. The activity of DB1195, DB1345, DB824 and DB1080 against bloodstream forms was reduced when these compounds were assayed in the presence of mouse blood possibly due to their association with plasma constituents and/or due to metabolic instability of the compounds. However, trypanocidal effects of DB613A and DB1196 were not affected by plasma constituents, suggesting their potential application in the prophylaxis of banked blood. In addition, potency and selectivity of DB613A, towards intracellular parasites, corroborate previous results that demonstrated the highly promising activity of arylimidamides against this parasite, which justify further studies in experimental models of T. cruzi infection.     

Synthesis and rheological properties of hydrogels based on amphiphilic alginate-amide derivatives

New amphiphilic derivatives of sodium alginate were prepared by covalent attachment of dodecylamine onto the polysaccharide via amide linkages at different substitution ratios, using 2-chloro-1-methylpyridinium iodide (CMPI) as coupling reagent. The aim was to limit the progressive loss of associative behaviour which occurs in the case of previously described dodecyl ester alginate derivatives due to hydrolysis of ester bonds. A series of hydrogels was obtained which differed by the amount of attached dodecyl tails. The stability and viscoelastic properties were evaluated and compared to those of hydrogels obtained with alginate esters. The observed differences were discussed in relation to the synthesis procedures. The advantages of amide links are underlined, especially with regard to long-term stability of hydrogels.     

Storage temperature influences desiccation and ultra violet radiation tolerance of entomopathogenic nematodes

1. The effect of cold (5 °C) and warm (35 °C) storage on desiccation tolerance of cold-adapted Steinernema feltiae, intermediate S. carpocapsae and warm-adapted S. riobrave was evaluated at 5 and 35 °C.     

Insecticidal activity of Bacillus thuringiensis crystal proteins

Published data on insecticidal activity of crystal proteins from Bacillus thuringiensis are incorporated into the Bt toxin specificity relational database. To date, 125 of the 174 holotype known toxins have been tested in ∼1700 bioassays against 163 test species; 49 toxins have not been tested at all; 59 were tested against 71 Lepidoptera species in 1182 bioassays; 53 toxins were tested against 23 Diptera species in 233 bioassays; and 47 were tested against 39 Coleoptera species in 190 bioassays. Activity spectra of the tested toxins were summarized for each order. Comparisons of LC₅₀ values are confounded by high variability of the estimates, mostly due to within-species variation in susceptibility, and errors associated with estimation of toxin protein content. Limited analyses suggest that crystal protein toxicity is not affected by quarternary toxin rank or host used for gene expression, but that pre-ingestion treatment by solubilization or enzymatic processing has a large effect. There is an increasing number of toxin families with cross-order activity, as 15 of the 87 families (secondary rank) that are pesticidal are active against more than one order. Cross-order activity does not threaten environmental safety of B. thuringiensis-based pest control because toxins tend to be much less toxic to taxa outside the family’s primary specificity range.     

Complete assignment of 1H and 13C NMR spectra of Gigartina skottsbergii lambda-carrageenan using carrabiose oligosaccharides prepared by enzymatic hydrolysis

lambda-Carrageenan extracted from Gigartina skottsbergii tetrasporophyte was completely digested by a purified Pseudoalteromonas carrageenovora lambda-carrageenase. The main digestion products were fractionated and analysed by (1)H and (13)C NMR spectroscopy. All the oligosaccharides observed belong to the neo-carrabiose oligosaccharide series indicating that the lambda-carrageenase cleaves the beta-(1-->4) glycosidic bonds. (1)H and (13)C NMR spectra recorded on oligomers from DP 2 to DP 8 were fully interpreted allowing unambiguous assignment of the lambda-carrageenan spectra. Besides the typical oligo-lambda-carrageenans, we have also characterised a heptasulfated tetrasaccharide which demonstrates the random over-sulfation along the chain of G. skottsbergii lambda-carrageenan.     

Preparation, properties and crystal structure of two isomers of R,R,S,S- and R,S,R,S-[chloro(1,3,10,12,16,19-hexaazatetracyclo[17,3,1,1,0]tetracosane)copper(II)]

Two isomers (R,S,R,S- and R,R,S,S-) of five coordinate complex [Cu(L)Cl]⁺ have been separated and characterised. These two isomers have significantly different spectrochemical and electrochemical properties. Absorption maximum of R,S,R,S-[Cu(L)Cl]⁺ shifts to longer wavelength and its reduction potential shifts to more positive direction comparing those of R,R,S,S-[Cu(L)Cl]⁺. R,S,R,S-[Cu(L)Cl]⁺ is significantly distorted to trigonal-bipyramidal structure, whereas R,R,S,S-[Cu(L)Cl]⁺ retains almost square-planar geometry. The average bond distance of Cu-N in basal plane of R,S,R,S-[Cu(L)Cl]⁺ is longer by 0.024 Å than that of R,R,S,S-[Cu(L)Cl]⁺, whereas the bond distance of Cu-Cl in former is shorter by 0.200 Å than that in latter. The isolated square-planar complexes of R,R,S,S- and R,S,R,S-[Cu(L)](ClO₄)₂ are converted to the R,R,S,S- and R,S,R,S-[Cu(L)Cl]⁺ by the addition of Cl⁻ in nitromethane solution with the rate constants, k=1.70 (±0.02) and 8.31 (±0.07) M⁻¹ s⁻¹, respectively.     

Synthesis of a C-galactopyranosyl-linked N-substituted 1,2-ethylenediamine

A straightforward route to a C-galactopyranosyl-linked 1,2-ethylenediamine is described. The five-step synthetic procedure involves: (i) C-allenylation of d-galactopyranose pentaacetate with propargyl trimethylsilane in the presence of a Lewis acid, (ii) iodination of allenyl galactopyranosyl tetraacetate to diiodoallyl galactopyranosyl tetraacetate, (iii) displacement of the allylic iodide with N-Boc-ethylenediamine, (iv) catalytic hydrogenation of vinyl iodide to alkane, (v) deprotection of the acetyl and N-Boc-groups using acid-catalyzed hydrolysis. This method demonstrates a general method to access a new class of carbohydrate-ethylenediamine C-glycosyl chelators.