Removal of methyl orange from aqueous solution by Azolla filicoloides:Synthesis of Fe_3O_4 nano-particles and its surface modification by the extracted pectin of Azolla

The modified Fe₃O₄ nano-particles with the extracted pectin from the cell wall of Azolla filicoloides（FN-EP） can remove methyl orange as a water-soluble azo dye from waste water better than Azolla and the extracted pectin from Azolla（EPA）,alone.It could be due to more crowding the main functional groups of uptake after binding pectin with nano-particles.Thermodynamic studies showed that adsorption equilibrium constant（K_L） and maximum adsorption capacities(Q_max) were increased with decreasing temperature（exothermic）.The maximum uptake capacity(Q_max) of dye by FN-EP in a batch reactor was 0.533,0.498 and 0.446 mmol/g at 5,25 and 50℃,respectively.The enthalpy change（△H） and entropy change（△S） were -15.31 kJ/mol and -0.02434 kJ/mol K,respectively.     

U(VI) biosorption by Azolla imbircata dry power from solution

Journal of Radioanalytical and Nuclear Chemistry - Azolla imbircata dry powder (Ai-dp) was prepared by collecting wild Azolla imbircata, drying and grinding. SEM, FTIR and XPS have been used to...     

Reveal 8-Hour Test System for detection of Escherichia coli O157:H7 in raw ground beef, raw beef cubes, and iceberg lettuce rinse: collaborative study.

Five different food types were analyzed by the Reveal for E. coli O157:H7 8-Hour Test System (Reveal 8) and either the U.S. Food and Drug Administration's Bacteriological Analytical Manual (BAM) culture method or the U.S. Department of Agriculture Food Safety Inspection Service (FSIS) culture method for the presence of E. coli O157:H7. A total of 27 laboratories representing academia and private industry in the United States and Canada participated. Food types were inoculated with E. coli O157:H7 at 2 different levels: a high level where predominantly positive results were expected, and a low level where fractional recovery was anticipated. During this study, 1,110 samples and controls were analyzed by both the Reveal 8 and by BAM or FSIS by each of the collaborators (2,220 samples in total). For each set of samples, 740 were artificially inoculated with E. coli O157:H7, and 370 were uninoculated controls. The Reveal 8 detected 528 presumptive positives of which 487 were confirmed positive by the BAM culture method. In comparison, BAM and FSIS detected 489 of the 740 artificially contaminated samples as positive. In an additional in-house study performed only on chilled and frozen raw ground beef, 240 artificially inoculated samples were analyzed by both the Reveal 8 and by FSIS. The Reveal 8 detected and confirmed 104 samples as positive compared to 79 confirmed positive by FSIS.     

UV-B-induced formation of reactive oxygen species and oxidative damage of the cyanobacterium Anabaena sp.: protective effects of ascorbic acid and N-acetyl-L-cysteine

Reactive oxygen species (ROS) are involved in the oxidative damage of the cyanobacterium Anabaena sp. caused by UV-B (280-315 nm) radiation. UV-B-induced overproduction of ROS as well as the oxidative stress was detected in vivo by using the ROS-sensitive probe 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA). Thiobarbituric acid reactive substances (TBARS) and fluorometric analysis of DNA unwinding (FADU) methods were adapted to measure lipid peroxidation and DNA strand breaks in Anabaena sp. Moderate UV-B radiation causes an increase of ROS production, enhanced lipid peroxidation and DNA strand breaks, yielding a significantly decreased survival. In contrast, the supplementation of UV-A in our work only showed a significant increase in total ROS levels and DNA strand breaks while no significant effect on lipid peroxidation, chlorophyll bleaching or survival was observed. The presence of ascorbic acid and N-acetyl-L-cysteine (NAC) reversed the oxidative stress and protected the organisms from chlorophyll bleaching and the damage of photosynthetic apparatus induced by UV-B significantly, resulting in a considerably higher survival rate. Ascorbic acid also exhibited a significant protective effect on lipid peroxidation and DNA strand breaks while NAC did not show a substantial effect. These results suggest that ascorbic acid exhibited significantly higher protective efficiency with respect to DNA strand breaks and survival than NAC while NAC appears to be especially effective in defending the photosynthetic apparatus from oxidative damage.     

Removal of <Superscript>60</Superscript>Co<Superscript>2+</Superscript> and <Superscript>137</Superscript>Cs<Superscript>+</Superscript> ions from low radioactive solutions using <Emphasis Type="Italic">Azolla caroliniana</Emphasis> willd. water fern

This study concerns the removal of the ¹³⁷Cs⁺ and ⁶⁰Co²⁺ β+γ-radioactive ions in Azolla caroliniana Willd. water fern. The living fern and two different types of biosorbent prepared from Azolla caroliniana were tested to remove the above-mentioned radioactive ions from dilute solutions, in the absence and in the presence of the ionic competition. Effective ¹³⁷Cs⁺ and ⁶⁰Co²⁺ ions removal from low radioactive wastewaters was demonstrated. The time dependent K _d (t) values were calculated from the absorption data. These results indicate that removal process achieved equilibrium in about 120 min and that it involves two steps: rapid and slow absorption; the active process (metabolic bioaccumulation on the living fern) was responsible for above one half of the total removal process. A thin layer radiochromatography study leads to the conclusion that the biochemical components in which ¹³⁷Cs⁺ and ⁶⁰Co²⁺ place themselves are of a polysaccharide and lipoid fractions.     

Isolation and Total Synthesis of Kirkamide,an Aminocyclitol from an Obligate Leaf Nodule Symbiont

The new C₇N aminocyclitol kirkamide ( 1 ) was isolated from leaf nodules of the plant Psychotria kirkii by using a genome‐driven ¹H NMR‐guided fractionation approach. The structure and absolute configuration were elucidated by HRMS, NMR, and single‐crystal X‐ray crystallography. An enantioselective total synthesis was developed, which delivered kirkamide ( 1 ) on a gram scale in 11 steps and features a Ferrier carbocyclization and a Pd‐mediated hydroxymethylation. We propose that kirkamide is synthesized by Candidatus Burkholderia kirkii, the obligate leaf symbiont of Psychotria kirkii. Kirkamide ( 1 ) was shown to be toxic to aquatic arthropods and insects, thus suggesting that bacterial secondary metabolites play a protective role in the Psychotria/Burkholderia leaf nodule symbiosis.     

STUDY ON PREPARATION AND APPLICATION OF MONOCLONAL ANTIBODIES TO Anabaena azollae

Forty hybridoma cell lines secreting monoclonal antibodies against Anabaena azollae have been established by fusing SP_2/O myeloma cells with spleen cells from BALB/c mice immunized with purified antigen Anabaena azollae from different strains of azolla.According to the fluorescent antibody test, 40 McAbs were divided into 8 types. They may differentiate the Anabaena azollae in 195 azolla strains which are collected from different places in the world, into 8 antigenic groups.The identifying result of Anabaena azollae isolated from reconstituted azolla and sexual hybrid azolla showed that the Anabaena azollae in the reconstituted azolla retains its antigenicity from the donor azolla, and Anabacna azollae in hybrid azolla maintains its antigenicity from the female parent plant.     

Current Density Distribution as Parameter of Electroionite Process

The effect of artificially preset current density distribution in an electroionite apparatus on the ex-tent of water demineralization is considered. The change in the extent of demineralization on varying the distribution of one, the same current between parts of apparatus at the inlet, outlet of diluate is explained.     

A Comparative Kinetic Analysis of the Flavin-Photosensitized Oxidation and Reduction of Plastocyanin and Cytochrome c6 from Different Organisms

Abstract— Laser flash photolysis spectroscopy has been used to investigate the kinetics of oxidation and reduction of pho-tosynthetic plastocyanin (Pc) and cytochrome c₆ (Cyt) from the cyanobacteria Anabaena PCC 7119 and Syne-chocystis PCC 6803 by lumiflavin, riboflavin and flavin mononucleotide (FMN). For both redox reactions similar steric and electrostatic effects were observed with Syne-chocystis proteins and Anabaena Cyt, thus suggesting that the same (or closely adjacent) sites are being used for electron entry and removal. In the case of Anabaena Pc, however, both the steric and electrostatic effects suggest that FMN-dependent protein oxidation and reduction may occur at different sites, that is oxidation at the hydrophobic patch and reduction at the hydrophilic one. Kinetic pK_a values of 5.8 and 6.2 have been determined for the lumiflavin-dependent reduction of Anabaena and Monoraphidium Pc, respectively, whereas the oxidation reactions appear to be pH independent. Not only the reduction kinetics but also protein tyrosine fluorescence quenching by iodide ions suggest the occurrence of pH-induced conformational changes in Pc. In conclusion, kinetic and fluorescent studies indicate that there are considerable quantitative similarities between Cyt and Pc when isolated from the same organism, consistent with the identical physiological role that these two proteins play inside the cells.     

Effect of light irradiance on the production of sulfolipids from Anabaena 7120 in a fed-batch photobioreactor

Sulfolipids have recently emerged as promising antiHIV and antitumor therapeutics. These lipids have been found in association with the photosynthetic apparatus in most photoautotrophic organisms. To date there have been no quantitative studies on the effect of environmental factors on the production of sulfolipid. In this study, we present results on the effect of light irradiance on the production of sulfolipids using the cyanobacteriumAnabaena 7120. The cyanobacteria are grown in a 2 L fedbatch photobioreactor at various external-light intensities. Total lipids are extracted using the Folsch procedure and sulfolipids are quantified using thin-layer chromatography and scanning densitometry. We have achieved a maximum of 14 mg sulfolipid/g dry weight of cell. Our results indicate that there are two stages in the specific rate of production of sulfolipids, one in the declining exponential-growth phase of the cells and the other in the light-limited stage of growth.     

Laminarin Induces Defense Responses and Efficiently Controls Olive Leaf Spot Disease in Olive

Olive leaf spot (OLS) caused by Fusicladium oleagineum is mainly controlled using copper fungicides. However, the replacement of copper-based products with eco-friendly alternatives is a priority. The use of plant resistance-inducers (PRIs) or biological control agents (BCAs) could contribute in this direction. In this study we investigated the potential use of three PRIs (laminarin, acibenzolar-S-methyl, harpin) and a BCA (Bacillus amyloliquefaciens FZB24) for the management of OLS. The tested products provided control efficacy higher than 68%. In most cases, dual applications provided higher (p < 0.05) control efficacies compared to that achieved by single applications. The highest control efficacy of 100% was achieved by laminarin. Expression analysis of the selected genes by RT-qPCR revealed different kinetics of induction. In laminarin-treated plants, for most of the tested genes a higher induction rate (p < 0.05) was observed at 3 days post application. Pal, Lox, Cuao and Mpol were the genes with the higher inductions in laminarin-treated and artificially inoculated plants. The results of this study are expected to contribute towards a better understanding of PRIs in olive culture and the optimization of OLS control, while they provide evidence for potential contributions in the reduction of copper accumulation in the environment.     

Microscopic measurement of circular dichroism spectra

A microscope device to measure the circular dichroism (CD) spectra of a specified microscopic region of chiral samples was constructed by combining of a couple of objective lenses and a CCD camera, which was installed in a sample chamber of a commercially available CD spectropolarimeter. By using this apparatus, high quality micro-CD spectra in the 60 x 60 microm region of samples could be measured. Micro-CD spectra of thin film of chiral DNA samples on glass and a natural kidney bean leaf were measured, and the potential of the micro-CD apparatus was successfully demonstrated.     

Composition and antimicrobial activity of the leaf and twig oils of Litsea acutivena from Taiwan

The chemical composition, and antimicrobial and anti-wood-decay fungal activities of the essential oils isolated from the leaves and twigs of Litsea acutivena of Taiwan were investigated. The essential oils from the fresh leaves and twigs were isolated using hydrodistillation in a Clevenger-type apparatus, and characterized by GC-FID and GC-MS. Ninety-five and fifty-two compounds were identified in the leaf and twig oils, respectively. The main components of the leaf oil were gamma-patchoulene (11.0%), delta-cadinene (6.3%), trans-muurola-3,5-diene (5.9%), and beta-selinene (5.3%), whereas the main components of the twig oil were tau-cadinol (13.1%), beta-selinene (9.6%), trans-beta-ocimene (6.2%) and alpha-cadinol (7.7%). Bioactivity studies demonstrated that twig oil had excellent antimicrobial and anti-wood-decay fungal activities, superior to those of the leaf oil. For the antimicrobial and anti-wood-decay fungal activities of the twig oil, the active compounds were determined to be tau-cadinol and alpha-cadinol.     

A direct and rapid leaf water extraction method for isotopic analysis

Isotopic measurements of leaf water have provided insights into a range of ecophysiological and biogeochemical processes, but require an extraction step which often constitutes the major analytical bottleneck in large-scale studies. Current standard procedures for leaf water analysis are based on cryogenic vacuum or azeotrophic distillation, and are laborious, require sophisticated distillation lines and the use of toxic materials. We report a rapid technique based on centrifugation/filtration of leaf samples pulverised in their original sampling tubes, using a specifically adapted, simple apparatus. The leaf water extracts produced are suitable for isotopic analysis via pyrolysis gas chromatography isotope ratio mass spectrometry (PYR/GC/IRMS). The new method was validated against cryogenic vacuum distillation and showed an overall accuracy of +/-0.5 per thousand (nine grouped comparisons, n = 110) over a range of 21 per thousand. Effects due to the presence of soluble carbohydrates were near the detection limits for most samples analysed, and these effects could be corrected for (the extracted soluble organics could also be used for isotopic analysis). The extraction time for a routine eight-sample subset was reduced from 4 h (cryogenic distillation) to 45 min, limited only by the size of the centrifuge(s) used. This method provides a rapid, low-cost and reliable alternative to conventional vacuum and other distillation methods that can alleviate current restrictions on ecosystem- and global-scale studies that require high-throughput leaf water isotopic analysis. Copyright (c) 2008 John Wiley & Sons, Ltd.     

Comparison of Petrifilm Staph Express Count System with the bacteriological analytical manual direct-plating method for enumeration of Staphylococcus aureus in artificially contaminated hard cheese

The 3M Petrifilm Staph Express Count System was compared with the U.S. Food and Drug Administration's Bacteriological Analytical Manual (BAM) direct-plate count method for the enumeration of Staphylococcus aureus in 6 types of artificially contaminated hard cheese (Asiago, Cheddar, Gruyère, Parmesan, Romano, and Swiss). Five different samples of each cheese type were inoculated with S. aureus (ATCC 25923) to achieve low, medium, and high inoculum levels. S. aureus was enumerated by the Petrifilm and BAM methods, and the results were compared. Multivariate analysis of variance revealed no significant differences (P<0.05) between the 2 methods. The Petrifilm method compared favorably with the BAM procedure. The rapid method was more convenient to use, considerably faster, and less expensive to perform than the BAM method.     

Studying the signaling role of 2-oxoglutaric acid using analogs that mimic the ketone and ketal forms of 2-oxoglutaric acid

2-Oxoglutaric acid (2-OG), a Krebs cycle intermediate, is a signaling molecule in many organisms. To determine which form of 2-OG, the ketone or the ketal form, is responsible for its signaling function, we have synthesized and characterized various 2-OG analogs. Only 2-methylenepentanedioic acid (2-MPA), which resembles closely the ketone form of 2-OG, is able to elicit cell responses in the cyanobacterium Anabaena by inducing nitrogen-fixing cells called heterocysts. None of the analogs mimicking the ketal form of 2-OG are able to induce heterocysts because none of them are able to interact with NtcA, a 2-OG sensor. NtcA interacts with 2-MPA and 2-OG in a similar manner, and it is necessary for heterocyst differentiation induced by 2-MPA. Therefore, it is primarily the ketone form that is responsible for the signaling role of 2-OG in Anabaena.     

Multicolor fluorescence imaging of leaves--a useful tool for visualizing systemic viral infections in plants

Abstract Multicolor fluorescence induced by UV light is a sensitive and specific tool that may be used to provide information about the primary and secondary metabolism of plants by monitoring signals of the chlorophyll fluorescence (Chl-F) and blue-green fluorescence (BGF), respectively. We have followed the systemic infection of Nicotiana benthamiana plants with the Pepper mild mottle virus (PMMoV) by means of a multicolor fluorescence-imaging system, to detect differences between two strains of PMMoV during the infection process and to establish a correlation between the virulence and changes induced in the host plant. Changes in both BGF and Chl-F were monitored. BGF increased mainly in the abaxial side of the leaf during pathogenesis and the corresponding images showed a clear vein-associated pattern in leaves of infected plants. HPLC analysis of leaf extracts was carried out to identify compounds emitting BGF, and determined that chlorogenic acid was one of the main contributors. BGF imaging was able to detect viral-induced changes in asymptomatic (AS) leaves before detection of the virus itself. Chl-F images confirmed our previous results of alterations in the photosynthetic apparatus of AS leaves from infected plants that were detected with other imaging techniques. Fluorescence ratios F440/F690 and F440/F740, which increase during pathogenesis, were excellent indicators of biotic stress.     

Evaluation of sample preparation methods for the isolation of Salmonella from alfalfa and mung bean seeds with the Bacteriological Analytical Manual's Salmonella culture method

Five pre-enrichment methods were evaluated for effectiveness with the U.S. Food and Drug Administration's Bacteriological Analytical Manual Salmonella culture method in recovering S. Stanley, S. Poona, and S. Muenchen from artificially contaminated alfalfa seeds, and S. Saintpaul, S. Anatum, and S. Infantis from artificially contaminated mung bean seeds. The methods included: (1) Soak.--Test portions were inoculated into pre-enrichment media; (2) Rinse.--Test portions were rinsed with pre-enrichment media, and the media was decanted from the test portions; (3) Rinsed seed.--Pre-enrichment media was added to the test portions that were rinsed in the rinse method; (4) Wet blend.--Test portions were blended with the pre-enrichment media; and (5) Dry blend.--Test portions were blended prior to pre-enrichment. The methods of pre-enrichment were also evaluated for effectiveness in recovering Pantoea agglomerans from alfalfa and mung bean seeds with a modified culture method for the recovery of Enterobacteriaceae from foods. The purpose of these studies was to provide a model for the recovery of Salmonella that may occur in seeds as a natural contaminant. The relative effectiveness of the soak method was consistently superior to the rinse method in isolating the selected Salmonella serovars from both seed types. Statistically, the rinsed seed method was as effective as the soak method in all trials, except 1 of 3, with S. Muenchen and alfalfa seeds (P > 0.05). The relative effectiveness of the methods in isolating P. agglomerans from alfalfa and mung bean seeds was similar to that observed with the artificially contaminated test portions. The soak method was consistently the most effective method and the rinse method was consistently the most ineffective method. The rinsed seed, wet blend, and dry blend methods were also as effective as the soak method in all 3 trials with each seed type (P > 0.05).     

Evaluation of a dry, rehydratable film method for rapid enumeration of Staphylococcus aureus

Results with the new 3M Petrifilm Rapid S. aureus Count (RSA) Plate method were compared with those of the classical Baird-Parker agar (BPA) method for detection and enumeration of Staphylococcus aureus. Studies on 219 bacterial strains demonstrated that the Petrifilm RSA plate is more sensitive than and as specific as the classical BPA method for confirmed identification of S. aureus. Counts of colonies from 71 pure cultures, 61 naturally contaminated food samples, and more than 750 artificially inoculated food samples showed that the Petrifilm RSA method was as effective as the classical BPA method for identification and enumeration of S. aureus. The Petrifilm RSA method gave results in one-third the time required for the classical method.     

Comparison of Atmospheric Pressure Chemical Ionization and Electrospray:Determination of Monogalactosyl Diacylglycerols from Cyanobacteria by Liquid Chromatography/Mass Spectrometry

Atmospheric pressure chemical ionization (APCI) and electrospray (ES) mass spectrometry (MS) in both positive and negative ionization modes coupled to high-performance liquid chromatography (HPLC) have been used for the characterization of monogalactosyl diacylglycerols (MGDG) from cyanobacteria Anabaena cylindrica and Aphanizomenon flos-aquae.