Hemin with Peroxidase Activity Can Inhibit the Oxidative Damage Induced by Ultraviolet A

Excessive reactive oxygen species (ROS), a highly reactive substance that contains oxygen, induced by ultraviolet A (UVA) cause oxidative damage to skin. We confirmed that hemin can catalyze the reaction of tyrosine (Tyr) and hydrogen peroxide (H₂O₂). Catalysis was found to effectively reduce or eliminate oxidative damage to cells induced by H₂O₂ or UVA. The scavenging effects of hemin for other free-radical ROS were also evaluated through pyrogallol autoxidation, 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·)-scavenging assays, and phenanthroline–Fe²⁺ assays. The results show that a mixture of hemin and tyrosine exhibits strong scavenging activities for H₂O₂, superoxide anion (O₂⁻·), DPPH·, and the hydroxyl radical (·OH). Furthermore, the inhibition of oxidative damage to human skin keratinocyte (HaCaT) cells induced by H₂O₂ or UVA was evaluated. The results show that catalysis can significantly reduce the ratio of cell apoptosis and death and inhibit the release of lactate dehydrogenase (LDH), as well as accumulation of malondialdehyde (MDA). Furthermore, the resistance to apoptosis was found to be enhanced. These results show that the mixture of hemin and tyrosine has a significantly protective effect against oxidative damage to HaCaT cells caused by UVA, suggesting it as a protective agent for combating UVA damage.     

Fast classification and compositional analysis of cornstover fractions using Fourier transform near-infrared techniques

The objectives of this research were to determine the variation of chemical composition across botanical fractions of cornstover, and to probe the potential of Fourier transform near-infrared (FT-NIR) techniques in qualitatively classifying separated cornstover fractions and in quantitatively analyzing chemical compositions of cornstover by developing calibration models to predict chemical compositions of cornstover based on FT-NIR spectra. Large variations of cornstover chemical composition for wide calibration ranges, which is required by a reliable calibration model, were achieved by manually separating the cornstover samples into six botanical fractions, and their chemical compositions were determined by conventional wet chemical analyses, which proved that chemical composition varies significantly among different botanical fractions of cornstover. Different botanic fractions, having total saccharide content in descending order, are husk, sheath, pith, rind, leaf, and node. Based on FT-NIR spectra acquired on the biomass, classification by Soft Independent Modeling of Class Analogy (SIMCA) was employed to conduct qualitative classification of cornstover fractions, and partial least square (PLS) regression was used for quantitative chemical composition analysis. SIMCA was successfully demonstrated in classifying botanical fractions of cornstover. The developed PLS model yielded root mean square error of prediction (RMSEP %w/w) of 0.92, 1.03, 0.17, 0.27, 0.21, 1.12, and 0.57 for glucan, xylan, galactan, arabinan, mannan, lignin, and ash, respectively. The results showed the potential of FT-NIR techniques in combination with multivariate analysis to be utilized by biomass feedstock suppliers, bioethanol manufacturers, and bio-power producers in order to better manage bioenergy feedstocks and enhance bioconversion.     

In vitro development and transfer of resistance to chlortetracycline in Bacillus subtilis

The present criteria and rules controlling the approval of the use of probiotics are limited to antibiotic resistance patterns and the presence of antibiotic resistance genes in bacteria. There is little information available in the literature regarding the risk of the usage of probiotics in the presence of antibiotic pressure. In this study we investigated the development and transfer of antibiotic resistance in Bacillus subtilis selected in vitro by chlortetracycline in a stepwise manner. Bacillus subtilis was exposed to increasing concentrations of chlortetracyclineto induce in vitro resistance to chlortetracycline, and the minimal inhibitory concentrations were determinedfor the mutants. Resistant B. subtilis were conjugated with Escherichia coli NK5449 and Enterococcus faecalis JH2-2 using the filter mating. Three B. subtilis tetracycline resistant mutants (namely, BS-1, BS-2, and BS-3) were derived in vitro. A tetracycline resistant gene, tet (K), was found in the plasmids of BS-1 and BS-2. Three conjugates (BS-1N, BS-2N, and BS-3N) were obtained when the resistant B. subtilis was conjugated with E. coli NK5449. The conjugation frequencies for the BS-1N, BS-2N, and BS-3N conjugates were 4.57×10^?7, 1.4×10^?7, and 1.3×10^?8, respectively. The tet(K) gene was found only in the plasmids of BS-1N. These results indicate that long-term use of probiotics under antibiotic selection pressure could cause antibiotic resistance, and the resistance gene could be transferred to other bacteria. The risk arising from the use of probiotics under antibiotic pressure should be considered in the criteria and rules for the safety assessment of probiotics.     

Microbial light-activatable proton pumps as neuronal inhibitors to functionally dissect neuronal networks in C. elegans

Essentially any behavior in simple and complex animals depends on neuronal network function. Currently, the best-defined system to study neuronal circuits is the nematode Caenorhabditis elegans, as the connectivity of its 302 neurons is exactly known. Individual neurons can be activated by photostimulation of Channelrhodopsin-2 (ChR2) using blue light, allowing to directly probe the importance of a particular neuron for the respective behavioral output of the network under study. In analogy, other excitable cells can be inhibited by expressing Halorhodopsin from Natronomonas pharaonis (NpHR) and subsequent illumination with yellow light. However, inhibiting C. elegans neurons using NpHR is difficult. Recently, proton pumps from various sources were established as valuable alternative hyperpolarizers. Here we show that archaerhodopsin-3 (Arch) from Halorubrum sodomense and a proton pump from the fungus Leptosphaeria maculans (Mac) can be utilized to effectively inhibit excitable cells in C. elegans. Arch is the most powerful hyperpolarizer when illuminated with yellow or green light while the action spectrum of Mac is more blue-shifted, as analyzed by light-evoked behaviors and electrophysiology. This allows these tools to be combined in various ways with ChR2 to analyze different subsets of neurons within a circuit. We exemplify this by means of the polymodal aversive sensory ASH neurons, and the downstream command interneurons to which ASH neurons signal to trigger a reversal followed by a directional turn. Photostimulating ASH and subsequently inhibiting command interneurons using two-color illumination of different body segments, allows investigating temporal aspects of signaling downstream of ASH.     

Development of mechanistically based model for simulating soluble microbial products generation in an aerated/non-aerated SBR

Soluble microbial products (SMPs) are considered as the main organic components in wastewater treatment plant effluent from biological wastewater treatment systems. To investigate and explore SMP metabolism pathway for further treatment and control, two innovative mechanistically based activated sludge models were developed by extension of activated sludge model no.3 (ASM3). One was the model by combining SMP formation and degradation (ASM3-SMP model) processes with ASM3, and the other by combining both SMP and simultaneous substrate storage and growth (SSSG) mechanisms with ASM3 (SSSG-ASM3-SMP model). The detailed schematic modification and process supplements were introduced for comprehensively understanding all the mechanisms involved in the activated sludge process. The evaluations of these two models were demonstrated by a laboratory-scale sequencing batch reactor (SBR) operated under aerated/non-aerated conditions. The simulated and measured results indicated that SMP comprised about 83% of total soluble chemical oxygen demand (SCOD) in which biomass-associated products (BAPs) were predominant compared with utilization-associated products (UAPs). It also elucidated that there should be a minimum SMP value as the reactive time increases continuously and this conclusion could be used to optimize effluent SCOD in activated sludge processes. The comparative results among ASM3, ASM3-SMP and SSSG-ASM3-SMP models and the experimental measurements (SCOD, ammonia and nitrate nitrogen) showed clearly the best agreement with SSSG-ASM3-SMP simulation values (R = 0.993), strongly suggesting that both SMP formation and degradation and SSSG mechanisms are necessary in biologically activated sludge modeling for municipal wastewater treatment.     

Cyanidin-3-glucoside, a natural product derived from blackberry, exhibits chemopreventive and chemotherapeutic activity

Epidemiological data suggest that consumption of fruits and vegetables has been associated with a lower incidence of cancer. Cyanidin-3-glucoside (C3G), a compound found in blackberry and other food products, was shown to possess chemopreventive and chemotherapeutic activity in the present study. In cultured JB6 cells, C3G was able to scavenge ultraviolet B-induced *OH and O2-* radicals. In vivo studies indicated that C3G treatment decreased the number of non-malignant and malignant skin tumors per mouse induced by 12-O-tetradecanolyphorbol-13-acetate (TPA) in 7,12-dimethylbenz[a]anthracene-initiated mouse skin. Pretreatment of JB6 cells with C3G inhibited UVB- and TPA-induced transactivation of NF-kappaB and AP-1 and expression of cyclooxygenase-2 and tumor necrosis factor-alpha. These inhibitory effects appear to be mediated through the inhibition of MAPK activity. C3G also blocked TPA-induced neoplastic transformation in JB6 cells. In addition, C3G inhibited proliferation of a human lung carcinoma cell line, A549. Animal studies showed that C3G reduced the size of A549 tumor xenograft growth and significantly inhibited metastasis in nude mice. Mechanistic studies indicated that C3G inhibited migration and invasion of A549 tumor cells. These finding demonstrate for the first time that a purified compound of anthocyanin inhibits tumor promoter-induced carcinogenesis and tumor metastasis in vivo.     

Characterization and function analysis of a cold-induced AmCIP gene encoding a dehydrin-like protein in Ammopiptanthus mongolicus.

A cDNA clone was isolated after difference screening from cotyledons of two-week cold-treated Ammopiptanthus mongolicus. The full-length cDNA sequence [designated as AmCIP (A. mongolicus cold-induced protein) gene] was 806 bp long and contained a 465 bp open reading frame (ORF) encoding a 16.6 kD protein of 154 amino acids. Bioinformatic analyses indicated that CIP belongs to dehydrin family with the features of high hydrophilicity, a helix K-segment, a long Gly-rich region and a phosphorylatable tract of Ser as well as deficiency in Cys and Trp. The expression of CIP gene increased after two weeks of cold treatment and more expression was detected in radicle than in cotyledon. And PCR amplification of the AmCIP gene from genome of A. mongolicus revealed this gene has no intron. Function prediction suggested this protein seems to protect the stabilization of membrane structure and prevent macromolecular coagulation or sequestrate calcium ions by association or disassociation with membrane under low temperature conditions.