Cadmium recovery by a sulfate-reducing magnetotactic bacterium,Desulfovibrio magneticus RS-1, using magnetic separation

Cadmium recovery by a sulfate-reducing magnetotactic bacterium, Desulfovibrio magneticus strain RS-1, was investigated. D. magneticus precipitated >95% of cadmium at an initial concentration of 1.3 ppm in the growth medium. Electron microscopic analysis revealed that D. magneticus formed electron-dense particles on its surface when cultivated in the presence of cadmium ions (Cd²⁺). Sulfide was also found in the precipitate, and the composition ratio of sulfide/cadmium was 0.7. Sixty percent of viable RS-1 cells was recovered by a simple magnetic separation revealing the removal of 58% cadmium from the culture medium.     

Effects of organic acids,amino acids and ethanol on the radio-degradation of patulin in an aqueous model system

The effects of organic acids, amino acids, and ethanol on the radio-degradation of patulin by gamma irradiation in an aqueous model system were investigated. The patulin, dissolved in distilled water at a concentration of 50 ppm, was practically degraded by the gamma irradiation at the dose of 1.0 kGy, while 33% of the patulin remained in apple juice. In the aqueous model system, the radio-degradation of patulin was partially inhibited by the addition of organic acids, amino acids, and ethanol. The proportions of remaining patulin after irradiation with the dose of 1.0 kGy in the 1% solution of malic acid, citric acid, lactic acid, acetic acid, ascorbic acid, and ethanol were 31.4%, 2.3%, 31.2%, 6.1%, 50.8%, and 12.5%, respectively. During 30 days of storage, the remaining patulin was reduced gradually in the solution of ascorbic acid and malic acid compared to being stable in other samples. The amino acids, serine, threonine, and histidine, inhibited the radio-degradation of patulin. In conclusion, it was suggested that 1 kGy of gamma irradiation (recommended radiation doses for radicidation and/or quarantine in fruits) is effective for the reduction of patulin, but the nutritional elements should be considered because the radio-degradation effects are environment dependent.     

Determination of traces of cadmium in alloy steels by anodic stripping voltammetry

Concentrations of cadmium of the order of 0.1 ppm in alloy steels containing large concentrations of chromium and nickel (ca. 17 and 13% respectively), about 0.1% of copper and a number of metals at low concentrations, were determined by anodic stripping voltammetry with a hanging mercury-drop electrode in 1M hydrochloric acid. Cadmium was separated on Dowex 50W-X8 cation-exchanger in a medium at pH 1.3 containing excess of EDTA. Mercury-film electrodes cannot be used for this determination, because the peak for cadmium is distorted by evolution of hydrogen on the electrode support. The relative standard deviation of the determination of 0.44 ppm of cadmium in steel is 3.2% and the confidence limits for 95% probability are 0.44 +/- 0.02 ppm. The error in the cadmium recovery does not exceed + 8%.     

Amazonian lignocellulosic materials-V

A plate-agar technique for fungal screening was applied to evaluate the xylanolytic activities of 18Penicillium janthinellum and 10Aspergillus sydowi species from the Amazon region. In order to compare these genera with those of other regions, oneAspergillus sp., one P.janthinellum, and 12 unknown genera from the southern region of Chile were studied. From these fungi strain,A. sydowi (56 strain) (25.2 IU/mL),P. janthinellum (671 strain) (47.3 IU/mL) from Amazonia,P. janthinellum (X4Z2 strain) (9.5 IU/mL), and anAspergillus sp. (X2M1 strain) (33.3 IU/mL) from the southern region of Chile were identified.     

Different growth response of Euglena gracilis to Hg, Cd, Cr and Ni compounds

The toxicity of inorganic mercury, nickel, chromium and cadmium on the unicellular photosynthetic flagellate Euglena gracilis, strain Z (E.g.) has been tested. Under the conditions used each metal impaired the growth rate of E.g., and had a very strong effect on cell motility. The degree of cytotoxicity and motility decreased from mercury iodide to cadmium chloride to cadmium nitrate to potassium dichromate to nickel sulfate. No mutagenic effects of the metals investigated have been observed. Adverse effects of metal compounds can be tested on the eukaryotic species of Euglena gracilis used as an intermediate model system between bacterial and animal model.     

Effect of Biochemical Stimulants on Biomass Productivity and Metabolite Content of the Microalga, Chlorella sorokiniana

The influence of 12 biochemical stimulants, namely 2-phenylacetic acid (PAA; 30 ppm), indole-3 butyric acid (IBA; 10 ppm), 1-naphthaleneacetic acid (NAA; 2.5, 5 and 10 ppm ), gibberellic acid (GA3, 10 ppm), zeatin (ZT; 0.002 ppm), thidiazuron (0.22 ppm), humic acid (20 ppm), kelp extract (250 ppm), methanol (500 ppm), ferric chloride (3.2 ppm ), putrescine (0.09 ppm), spermidine (1.5 ppm) were prescreened for their impact on growth and chlorophyll for the green alga—Chlorella sorokiniana. C. sorokiniana responded best to phytohormones in the auxin family, particularly NAA. Thereafter, two studies were conducted on combinations of phytohormones to compare blends from within the auxin family as well as against other families. These treatments were NAA_{5 ppm}+PAA_{30 ppm}, NAA_{2.5 ppm}+PAA_15 ppm, NAA_5 ppm+IBA_10 ppm, NAA_5 ppm+GA3_10 ppm, NAA_5 ppm+ZT_1 ppm, and NAA_5 ppm+GA3_10 ppm+ZT_1 ppm. Combinations of NAA with other auxins did not have synergistic or antagonistic effects on the growth. However, combinations of compounds from different phytohormone families, such as NAA_5 ppm+GA3_10 ppm+ZT_1 ppm, dramatically increased the biomass productivity by 170% over the control followed by the treatments: NAA _5 ppm+GA3_10 ppm (138%), NAA _5 ppm+ZT_1 ppm (136%), and NAA _5 ppm ( 133%). The effect of biochemical stimulants were also measured on metabolites such as chlorophyll, protein, and lipids in C. sorokiniana. Renewed interest in microalgae for biotechnology and biofuel applications may warrant the use of biochemical stimulants for cost reduction in large-scale cultivation through increased biomass productivity.     

Larvicidal activity of some secondary lichen metabolites against the mosquito Culiseta longiareolata Macquart (Diptera: Culicidae)

The larvicidal activity of some lichen metabolites, (+)-usnic acid, atranorin, 3-hydroxyphysodic acid and gyrophoric acid, against the second and third instar larvae of the mosquito Culiseta longiareolata were studied. All metabolites caused high larvicidal activities. When metabolites were compared on the basis of their LC(50) values, the order of increasing toxicity was as follows: gyrophoric acid (0.41?ppm)?>?(+)-usnic acid (0.48?ppm)?>?atranorin (0.52?ppm)?>?3-hydroxyphysodic acid (0.97?ppm). However, when LC(90) values were compared, the order of toxicity was (+)-usnic acid (1.54?ppm)?>?gyrophoric acid (1.93?ppm)?>?3-hydroxyphysodic acid (4.33?ppm)?>?atranorin (5.63?ppm). In conclusion, our results found that lichen secondary metabolites may have a promising role as potential larvicides.     

Synthesis and Evaluation of a Molecularly Imprinted Polymer for Pre-concentration of Patulin from Apple Juice

Patulin, (4-hydroxy-4H-furo[3,2-c] pyran-2(6H)-one) is a toxic secondary metabolite produced by a wide range of fungal species growing on some fruits, including apples. A novel molecularly imprinted polymer (MIP) for patulin has been synthesized using oxindole as a dummy template. The synthesis of MIPs based on dummy templates is a solution to overcome “template bleeding” shortcoming in trace analysis. The polymer was prepared in a non-covalent approach with methacrylic acid as functional monomer and ethylene glycol dimethacrylate as cross-linker via free radical polymerization. It was revealed that the MIP particles in extraction columns displayed high affinity towards patulin and, therefore, subsequently employed for molecularly imprinted-solid phase extraction (MIP-SPE) of patulin from contaminated apple juice samples. The analysis of spiked samples showed good recoveries (>80%). Reproducibility, repeatability, and limit of detection of the proposed method were also investigated.     

Specific assay for homoserine and its lactone in Pisum sativum. Preparation of homoserine hydroxamic acid

The existence of homoserine lactone in Pisum sativum seedlings is demonstrated. L-Homoserine lactone reacts with hydroxylamine, at neutral or alkaline pH, to form homoserine hydroxamic acid. Procedures are described for preparing L-homoserine lactone and L-homoserine hydroxamic acid. The hydroxamic acid yields a color with maximum absorbance at 492 nm with Fe³⁺ in 0.25 N HCl. This reaction permitted assay for total homoserine and homoserine lactone. Six-day old Pisum sativum seedlings, with cotyledons removed, were extracted with 90% ethanol. Evaporation of the ethanol and addition of Na₂SO₄ solution and toluene and centrifugation removed protein lipids and esters. After clarification with activated charcoal, homoserine lactone content was estimated by reaction with NH₂OH and Fe³⁺ reagents. For total homoserine, protein precipitation was with 2 N HCl and toluene. Evaporation to dryness at 60 °C under vacuum converted all homoserine to the lactone. The values found for total homoserine (μmols/g, wet weight) and preformed lactone (%) with the various growth media used were as follows: nitrate 87.4 (14.7%), NH₂OH 75.2 (6.3%), water 70.5 (7.9%), urea 56.4 (18.9%). Acetic anhydride added to homoserine hydroxamic acid forms acetohydroxamic acid, which yields a color with maximum absorbance at 505 nm with Fe³⁺. This color reaction is seven times as sensitive as the reaction of Fe³⁺ with homoserine hydroxamic acid itself.     

Speziesanalytik von Cadmium und Thallium in nativen Rapspflanzen (Brassica napus)

Summary The speciation of cadmium and thallium was studied in leaves from unpolluted rape of two different growth stages. In average the cytoplasmic fraction contained 37% of the whole cadmium or 84% of the whole thallium, respectively. Gel filtration of the cytoplasmic samples revealed a high (M>80,000 g/mol) and two low molecular weight cadmium species (M=4400 g/mol), but only one thallium species (M=3800 g/mol). No free ionic species have been detected. The determinations of metals were performed by ET-AAS, with a recovery between 60% and 90%. The low molecular weight species containing most of the cadmium was further purified by means of ion-exchange chromatography and gel filtration. The resulting strong anionic peptide showed a low absorption at 280 nm. The molar cadmium/peptide ratio was about 1/140. An amino acid analysis indicated no cysteine or methionine. Conclusively, the main cytoplasmic cadmium species in native rape neither belongs to the well known classes of sulphureous phytochelatins nor to the metallothioneins.

---

---

Herrn Prof. Dr. Wilhelm Fresenius zum 75. Geburtstag in Verehrung gewidmet     

Spectrophotometric Estimation of Carbaryl Residue in Some Home Garden Vegetables

Abstract

Residues of carbaryl (1-Naphthyl N-methly carbamate) were determined in the fruit and foliage of seven home garden vegetables by a spectrophotometric method. Residues at harvest averaged the following levels; cabbage (head, 0.0 ppm), cucumber (foliage 0.0 ppm; fruit, 0.05 ppm), garden bush beans (fruit, 0.0 ppm), Okra (foliage, 0.0 ppm; fruit, 0.01 ppm), pepper (foliage, 2.72 ppm; fruit, 0.9 ppm), squash (foliage, 6.55 ppm; fruit, 0.0 ppm), and tomato (foliage, 2.07 ppm; green fruit, 0.09 ppm; mature fruit, 0.03 opm). Foliage of the vegetables contained higher concentrations of the insecticide, in most cases, than did the fruits. Even with excessive applications, the carbaryl residues were found to be below the tolerance level established by EPA.     

Determination of phenolic compounds,in vitro antioxidant activity and characterization of secondary metabolites in different parts of Passiflora cincinnata by HPLC-DAD-MS/MS analysis

Abstract

Ethanol extracts of different parts of Passiflora cincinnata were obtained by maceration. The total phenolic and flavonoid contents were evaluated. The antioxidant activities were determined by β-carotene-linoleic acid bleaching test, 2,2-diphenyl-1-picrylhydrazil (DPPH), and 2,2’-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging. The crude ethanol stem extract showed the highest amount of total polyphenols (45.53?mg gallic acid equivalent/g) while the highest total flavonoid contents (1.42?mg of quercetin equivalent/g) were observed in the leaf extract. The lowest IC₅₀ (25.65?μg/ml) by the DPPH method was observed for the stem extract. The ABTS method showed a significant antioxidant activity for all investigated extracts. The secondary metabolite composition of ethanol extracts was assessed by HPLC-DAD-MS/MS analysis, leading to the identification of fourteen secondary metabolites in P. cincinnata extracts. These results showed the potentiality of this species as a source of phenolic compounds and antioxidants.     

Determination of Traces of Copper,Lead, and Cadmium in Cobalt by Derivative Pulse Polarography

Abstract

A derivative pulse polarographic method is described for determining traces of copper, lead and cadmium in cobalt and its compounds without separation. In hydrochloric acid medium the detection limits are respectively about 0.02, 0.04 and 0.1 ppm in metallic cobalt when analysing 2 M cobalt solutions. The procedure was applied to the analyses of synthetic and commercially available cobalt samples and showed a satisfactory sensitivity and precision at various concentrations levels of the three impurities.     

Urine metabolomic characteristics of female patients with occupational chronic cadmium poisoning after 15 years of treatment

Occupational chronic cadmium poisoning (OCCP) can cause irreversible organ damage. Currently, no effective treatment is available for OCCP, and effective and sensitive biomarkers for treatment evaluation are still lacking. In this study, metabolomics techniques were used to analyze changes in endogenous metabolites in the urine of patients with OCCP after 15 years of treatment. Thirty urine samples from female patients with OCCP and healthy female controls (n = 15 per group) were assessed using gas chromatography–time-of-flight mass spectrometry and ultra-high-performance liquid chromatography–Q-Exactive mass spectrometry. The OCCP group had higher concentrations of blood urea nitrogen and urinary cadmium but near-normal urinary concentrations of β₂-microglobulin and retinol-binding protein. Compared with the control group, the OCCP group had 66 significantly different metabolites with a variable importance in projection score >1 and p < 0.05. These differential metabolites were involved in various metabolic pathways, such as creatine metabolism, nicotinate and nicotinamide metabolism, the pentose phosphate pathway, d -glutamine and d -glutamate metabolism, and amino acid metabolism. Compared with the control group, the OCCP group had significantly higher urinary concentrations of creatine, glutamic acid, quinolinic acid and nicotinic acid. In a receiver operator characteristic analysis, the area under the curve of creatine was higher than those for glutamic acid, quinolinic acid and nicotinic acid, indicating that urinary concentrations of creatine could be used as a sensitive biomarker for the diagnosis and prognosis of OCCP and for monitoring its treatment.     

Production of insoluble exopolysaccharide of Agrobacterium sp. (ATCC 31749 and IFO 13140)

Agrobacterium isolated from soil samples produced two extracellular polysaccharides: succinoglycan, an acidic soluble polymer, and curdlan gum, a neutral, insoluble polymer. Maize glucose, cassava glucose, and maize maltose were used in fermentation medium to produce insoluble polysaccharide. Two Agrobacterium sp. strains which were used (ATCC 31749 and IFO 13140) in the production of insoluble exopolysaccharide presented equal or superior yields compared to the literature. The strain ATCC 31749 yielded better production when using maize maltose, whose yield was 85%, whereas strain IFO 13140 produced more when fed maize glucose, producing a yield of 50% (on reducing sugars).     

Immobilization of plant cells in hybrid sol-gel materials

Cells of three different plant species were immobilized on a glass fiber fabric by sol-gel deposition. The process involved the following steps: (1) reinforcement of glass-fiber supports by coating with a gelling solution of hybrid-SiO₂ precursors, (2) entrapment of cells by stuffing the voids of the support with a suspension cell culture, (3) achievement of a definite immobilization by a primary treatment with SiO₂-sol, followed by gas phase reaction of tetraethoxysilane and diethoxymethylsilane with OH groups of cell wall and of surface silica. Immobilized cells maintained their viability as tested by the positive reaction to TTC and by the development of calli from stretched samples. The samples did not release cells in solution over a time period of four months, at least. The biosynthetic capability of one of immobilized species, Coronilla vaginalis, was studied by periodically monitoring the production of umbelliferone and marmesin which constituted the major secondary metabolites produced by in vitro cultured cells of this species. The results were evaluated in order to determine the versatility of the method and its potential for exploitation in continuous industrial-scale production of rare and fine chemicals.Abbreviations 2,4-D = 2,4-dichlorophenoxyacetic acid - K = kinetin - IAA = indol-3-acetic acid - NAA = naphthalenacetic acid - B5 = Gamborg's medium - MS = Murashige and Skoog medium - TEOS = tetraethoxysilane - DEMS = diethoxymethylsilane - DEDMS = diethoxydimethylsilane - TTC = tetrazolium salt     

Effect of the medium pH on the release of secondary metabolites from roots ofDatura stramonium,Catharanthus roseus,andTagetes patula cultured in vitro

The release of alkaloids from root culturesDatura stramonium andCatharanthus roseus and thiophenes from root cultures ofTagetes patula was found to increase when the pH of the culture media (ranging from 4.8 to 7.0) was reduced to 3.5. The extent of the effect was different in each type of culture. Increases ranged from 4- to 20-fold, which in some cases accounted for 75% of the total secondary metabolite pool produced per flask. When the release of individual metabolites was measured, even larger increases, were observed (nearly 400-fold for ajmalicine). Increased release of alkaloids fromC. roseus roots were also observed in cultures growing in a 14-L fermentor, when the medium pH was reduced. Reduction of the pH of the media did not affect growth of the root cultures in subsequent subcultures. The importance of this treatment as a stategy to improve the recovery of secondary metabolites from producing cultures is discussed.     

Production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from cottonseed oil and valeric acid in batch culture of Ralstonia sp. strain JC-64

A Ralstonia sp. strain JC-64 that is capable of accumulating poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P[3HB-co-3HV]) from cottonseed oil and valeric acid was isolated. By using a high limiting-nitrogen (HLN) mineral medium as the medium for the second stage of the fermentation process and by adding the two carbon sources at different times, a range of copolymers with 12–62 mol% of 3HV were produced from a series of HLN mineral mediums containing different compositions of cottonseed oil and valeric acid by Ralstonia sp. JC-64. The melting temperature (T _m ) of polyhydroxybutyrate from cottonseed oil was 174°C and that of P(3HB-co-3HV) with the highest 3HV-mol fraction (62%) was 81°C.     

Standardized high-performance liquid chromatography of 182 mycotoxins and other fungal metabolites based on alkylphenone retention indices and UV-VIS spectra (diode array detection)

A general standardized method for the analysis of mycotoxins and other fungal secondary metabolites has been developed, based on high-performance liquid chromatography (HPLC) with an alkylphenone retention index and photodiode-array detection combined with thin-layer chromatography (TLC) in two different eluents. Each fungal secondary metabolite is characterized by its bracketed alkylphenone retention time index, its UV-VIS absorption maxima and its retardation factors relative to griseofulvin in two TLC eluents. This system is effective for the comparison of chemotaxonomic data in different laboratories and for a precise identification of fungi based on organic solvent extracts of fungal cultures. All important groups of mycotoxins and other fungal secondary metabolites could be detected in the HPLC system described and data are listed for 182 metabolites. The fungal secondary metabolites separated and characterized include aflatoxin B1, B2, G1 and G2, ochratoxin A, citrinin, penicillin acid, viomellein, penitrem A, patulin, sterigmatocystin, alternariol, tenuazonic acid, trichothecenes, roquefortines, fusarin C, zearalenone, PR-toxin, citreoviridin, viridicatumtoxin, verruculogen, rugulosin, cyclopiazonic acid, penicillin G and many other alkaloids, polyketides and terpenes.     

Characterisation of B(a)P metabolites formed in an ex vivo pig skin model using three complementary analytical methods

An original method was developed to separate, identify and quantify the different benzo(a)pyrene (B(a)P) metabolites formed through oxidative and conjugative pathways. All B(a)P metabolites were separated by an improved high-performance liquid chromatography method, then detected and quantified relatively by online radioactivity detection. At the same time, metabolite structures were characterised by tandem mass spectrometry using two complementary ionisation modes: electrospray ionisation in the negative mode and atmospheric pressure chemical ionisation in the positive mode. This method was successfully applied to the analysis of B(a)P metabolites, produced by incubation of B(a)P with the ex vivo pig ear skin model. These include glucuronic acid and sulphate conjugates of B(a)P-OHs and B(a)P-diols, as well as direct phase I metabolites: B(a)P-tetrol, B(a)P-diones, B(a)P-catechols, B(a)P-diols and B(a)P-OHs.