A novel higher polyhydroxybutyrate producer Halomonas halmophila 18H with unique cell factory attributes

For cost-competitive biosynthesis of polyhydroxybutyrate (PHB), the screening of efficient producers and characterization of their genomic potential is fundamental. In this study, 94 newly isolated halophilic strains from Turkish salterns were screened for their polyhydroxyalkanoates (PHAs) biosynthesis capabilities through fermentation. Halomonas halmophila 18H was found to be the highest PHB producer, yielding 63.72 % of its biomass as PHB. The PHB produced by this strain was physically and chemically characterized using various techniques. Its genome was also sequenced and found to be large (6,713,657 bp) and have a GC content of 59.9 %. Halomonas halmophila 18H was also found to have several copies of PHB biosynthesis genes, as well as 20 % more protein-coding genes and 1075 singletons compared to other high PHB producers. These unique genomic features make it a promising cell factory for the simultaneous production of PHAs and other biotechnologically important secondary metabolites.

A Comparative Study of Receptor-Targeted Magnetosome and HSA-Coated Iron Oxide Nanoparticles as MRI Contrast-Enhancing Agent in Animal Cancer Model

Magnetosomes are specialized organelles arranged in intracellular chains in magnetotactic bacteria. The superparamagnetic property of these magnetite crystals provides potential applications as contrast-enhancing agents for magnetic resonance imaging. In this study, we compared two different nanoparticles that are bacterial magnetosome and HSA-coated iron oxide nanoparticles for targeting breast cancer. Both magnetosomes and HSA-coated iron oxide nanoparticles were chemically conjugated to fluorescent-labeled anti-EGFR antibodies. Antibody-conjugated nanoparticles were able to bind the MDA-MB-231 cell line, as assessed by flow cytometry. To compare the cytotoxic effect of nanoparticles, MTT assay was used, and according to the results, HSA-coated iron oxide nanoparticles were less cytotoxic to breast cancer cells than magnetosomes. Magnetosomes were bound with higher rate to breast cancer cells than HSA-coated iron oxide nanoparticles. While 250 μg/ml of magnetosomes was bound 92 ± 0.2%, 250 μg/ml of HSA-coated iron oxide nanoparticles was bound with a rate of 65 ± 5%. In vivo efficiencies of these nanoparticles on breast cancer generated in nude mice were assessed by MRI imaging. Anti-EGFR-modified nanoparticles provide higher resolution images than unmodified nanoparticles. Also, magnetosome with anti-EGFR produced darker image of the tumor tissue in T2-weighted MRI than HSA-coated iron oxide nanoparticles with anti-EGFR. In vivo MR imaging in a mouse breast cancer model shows effective intratumoral distribution of both nanoparticles in the tumor tissue. However, magnetosome demonstrated higher distribution than HSA-coated iron oxide nanoparticles according to fluorescence microscopy evaluation. According to the results of in vitro and in vivo study results, magnetosomes are promising for targeting and therapy applications of the breast cancer cells.

Selection of newly isolated mushroom strains for tolerance and biosorption of zinc in vitro

Nine newly isolated mushroom strains were tested to assess both their zinc tolerance and potential for zinc removal from an aqueous solution. Four strains of ectomycorrhizal fungi, namely Clavariadelphus truncatus (T 192), Rhizopogon roseolus (T 21), Lepista nuda (T 373), and Tricholoma equestre (T 174), along with five strains of white rot fungi, Lenzites betulina (S 2), Trametes hirsuta (T 587), Ganoderma spp. (T 99), Polyporus arcularius (T 438), and Ganoderma carnosum (M 88), were investigated using zinc-amended solid and liquid media. Their biosorption properties were also determined. The colony diameter and dry weight were used as tolerance indices for fungal growth. C. truncatus and T. equestre were not strongly inhibited at the highest concentrations of (225 mg/l) zinc in solid media. The most tolerant four strains with solid media, C. truncatus, G. carnosum, T. hirsuta, and T. equestre, were then chosen for tolerance tests in liquid media. An ectomycorrhizal strain, C. truncatus, was also detected as the most tolerant strain in liquid media. However, the metal-tolerant strains demonstrated weak activity in the biosorption studies. In contrast, the highest biosorption activity was presented by a more sensitive strain, G. carnosum. In addition, seven different biosorbent types from G. carnosum (M 88) were compared for their Zn (II) biosorption in batch experiments.

Study on the characterization of lead (II) biosorption by fungus Aspergillus parasiticus

The lead (II) biosorption potential of Aspergillus parasiticus fungal biomass has been investigated in a batch system. The initial pH, biosorbent dosage, contact time, initial metal ion concentrations and temperature were studied to optimize the biosorption conditions. The maximum lead (II) biosorption capacity of the fungal biosorbent was found as 4.02 x 10(-4) mol g(-1) at pH 5.0 and 20 degrees C. The biosorption equilibrium was reached in 70 min. Equilibrium biosorption data were followed by the Langmuir, Freundlich and Dubinin- Radushkevich (D-R) isotherm models. In regeneration experiments, no significant loss of sorption performance was observed during four biosorption-desorption cycles. The interactions between lead (II) ions and biosorbent were also examined by FTIR and EDAX analysis. The results revealed that biosorption process could be described by ion exchange as dominant mechanism as well as complexation for this biosorbent. The ion exchange mechanism was confirmed by E value obtained from D-R isotherm model as well.

Biosorption characteristics of Bacillus sp. ATS-2 immobilized in silica gel for removal of Pb(II)

The bacterial strain Bacillus sp. ATS-2 isolated from Pb(II) polluted soil was immobilized with a silica matrix and Pb(II) biosorption properties of immobilized biosorbent were examined. Optimum biosorption conditions were investigated in the fixed bed column with the variation in the parameters of pH, bed length, flow rate and influent concentration. The Pb(II) biosorption equilibrium was attained within 60 min and the maximum biosorption yield for silica gel immobilized Bacillus sp. ATS-2 was determined as 91.73% at pH 4.0. The higher biosorption yields were observed at flow rates of 60 and 180 ml h(-1). The optimum bed length for the column was found as 10 cm. Data obtained from batch studies were evaluated by Freundlich, Langmuir and Dubinin-Radushkevich (D-R) isotherm models. The maximum monolayer capacity of Bacillus sp. ATS-2 for Pb(II) was 2.36 x 10(-5) mol g(-1). The involvement of the functional groups on the surface of immobilized cells in biosorption process was also evaluated by FTIR spectral analysis.

Biodegradation of Cyanide by a White Rot Fungus, Trametes versicolor

The cyanide degradation abilities of three white rot fungi, Trametes versicolor ATCC 200801, Phanerochaete chrysosporium ME 496 and Pleurotus sajor-caju, were examined. T. versicolor was the most effective with 0.35 g dry cell/100 ml degrading 2 mM KCN (130 mg/l) over 42 h, at 30 degrees C, pH 10.5 with stirring at 150 rpm.

Biosorption potential of the macrofungus Ganoderma carnosum for removal of lead(II) ions from aqueous solutions

This paper reports the utilization of a macro-fungus Ganoderma carnosum as a biosorbent material for the removal of lead(II) ions from aqueous solutions. The biosorption potential of G. carnosum was investigated by batch experiments. The influences of physico-chemical parameters like pH, biosorbent dosage, contact time and initial metal ion concentration were evaluated. The biosorption equilibrium was attained in 10 minutes. Equilibrium biosorption data were analyzed by the Freundlich, Langmuir and Dubinin-Radushkevich (D-R) isotherm models. Maximum biosorption capacity of biosorbent was found to be 22.79 mg g(-1) (1.10 x 10(-4) mol g(-1)) at the pH value of 5.0. The biosorbent was regenerated using 10 mM HCl solution, with up to 96% recovery, and reused four times in biosorption-desorption cycles successively. Biosorption efficiency of G. carnosum was also examined in a real effluent. The mechanism of the biosorption was investigated with FTIR, SEM and EDAX analysis and the findings suggested that the biosorption process involved in ion exchange as dominant mechanism as well as complexation. The ion exchange mechanism was also confirmed by the mean free energy value obtained from D-R isotherm model.

Working Memory in Schizophrenia as Revealed by Event-Related Potentials

Abstract: In this study, we compared working memory (WM) functions for simple actions of healthy subjects and schizophrenic patients by means of behavioral and ERP measures. Healthy subjects showed a large frontal N2 amplitude in the hard WM task with updating demands of temporal sequence, but not in the easy WM and the control task. Schizophrenic patients had large frontal N2 amplitudes in all tasks without difference indicating that the patients had to activate the frontal cortex in tasks in which healthy subjects use automatized routines which do not involve the frontal cortex. Strong negative symptoms in schizophrenic patients were associated with small N2 amplitudes thus supporting the hypothesis of joint causes of cognitive and psychopathological features.