Proteomic and physiological analyses reveal detoxification and antioxidation induced by Cd stress in Kandelia candel roots

The heavy metal Cadmium (Cd), added to the water bodies through weathering of rocks and human activities, constitutes one of the major environmental pollutants toxic to plants. This study examines the proteome changes in roots of actively growing Kandelia candel (L.) Druce when challenged with Cd. This mangrove-like species proliferates in estuaries and bays and is a potential choice for phytoremediation of Cd. A total of 53 proteins were up- or down-regulated following a short-term Cd treatment. The identities of the differentially expressed proteins were determined by MALDI-TOF/TOF. Approximately half of the up-regulated proteins are involved in oxidative response, including antioxidant enzymes, enzymes required for glutathione biosynthesis, enzymes in TCA and PPP cycles for generating ATP, NADH and NADPH. These results support the prediction that a prompt antioxidative response is necessary for the reduction of the oxidative stress caused by Cd and set the stage for further investigating of Cd up-regulated proteins in Kandelia candel.     

Cloning and characterization of a novel cry8Ab1 gene from Bacillus thuringiensis strain B-JJX with specific toxicity to scarabaeid (Coleoptera: Scarabaeidae) larvae

Isolation of Bacillus thuringiensis (Bt) strain or its cry gene encoding insecticidal crystal protein (ICP) with specific toxicity is of great importance to biological control of insect pests. In this study, by screening 66 strains of Bt isolated from soil samples collected in Shandong Province, China, a new cry8-type gene from Bt strain B-JJX was identified via PCR-RFLP method. This novel gene, cry8Ab1, was cloned from the Bt strain B-JJX and expressed in an acrystalliferous mutant strain HD-73^?. The open reading frame of the cry8Ab1 gene consists of 3543 bp with a G + C content of 37.99% and encodes a protein of 1180 amino acids with a putative MW of 133.3 kDa which was confirmed by SDS-PAGE analysis. The Cry8Ab1 protein was expressed and released as spherical parasporal crystals from Bt acrystalliferous mutant strain HD-73^? along with the presence of spores. In bioassays, this protein was toxic to 3-day-old larvae of the scarabaeid pests, Holotrichia oblita and H. parallela, with an LC₅₀ of 5.72 and 2.00 μg toxin g^?1 soil, respectively. The results are in accordance with the insecticidal activities of the original Bt strain B-JJX, which had an LC₅₀ of 1.72 and 0.96 μg toxin g^?1 soil against H. oblita and H. parallela, respectively.     

Genome-wide identification and expression profiling of ankyrin-repeat gene family in maize

Members of the ankyrin repeats (ANK) gene family encode ANK domain that are common in diverse organisms and play important roles in cell growth and development, such as cell-cell signal transduction and cell cycle regulation. Recently, genome-wide identification and evolutionary analyses of the ANK gene family have been carried out in Arabidopsis and rice. However, little is known regarding the ANK genes in the entire maize genome. In this study, we described the identification and structural characterization of 71 ANK genes in maize (ZmANK). Then, comprehensive bioinformatics analyses of ZmANK genes family were performed including phylogenetic, domain and motif analysis, chromosomal localization, intron/exon structural patterns, gene duplications and expression profiling. Domain composition analyses showed that ZmANK genes formed ten subfamilies. Five tandem duplications and 14 segmental duplications were identified in ZmANK genes. Furthermore, we took comparative analysis of the total ANK gene family in Arabidopsis, rice and maize, ZmANKs were more closely paired with OsANKs than with AtANKs. At last, expression profile analyses were performed. Forty-one members of ZmANK genes held EST sequences records. Semi-quantitative expression and microarray data analysis of these 41 ZmANK genes demonstrated that ZmANK genes exhibit a various expression pattern, suggesting that functional diversification of ZmANK genes family. The results will present significant insights to explore ANK genes expression and function in future studies in maize.     

Characterisation of H+ and Cu2+ binding to humic and fulvic acids

Abstract

The nature of H⁺ and Cu²⁺ binding by soil-derived humic (HA) and fulvic (FA) acid was characterised using potentiometric titrations. The experimental data obtained showed that the derived proton balance equation was valid and capable of describing proton consumption by both polyelectrolytes. HA was found to be more acidic and more reactive as shown by its lower equivalent weight compared to FA. Acid consumption by HA during titrations was little affected at ionic strength (μ) up to 0.1 M although it was enhanced at higher μ. Displacement of protons by Cu²⁺ resulted in a nonlinear sigmoidal pattern suggesting the formation of different Cu-HA chelates, or existence of sites that differed in their affinities for Cu on the ligand. Different concentrations of added Cu appeared to favour one or both mechanisms, although the titration method could not differentiate which of the probable mechanisms was more dominant at a specific level of Cu added. Similar values were obtained for conditional stability constants using either the equation of Scatchard or Ruzic.     

Optimization of soluble human interferon-γ production in Escherichia coli using SUMO fusion partner

Interferon-γ (IFN-γ) is a broad-spectrum antiviral glycoprotein that produced by lymphatic T cells and natural killer cells those who had stimulated by antigen. Human IFN-γ (hIFN-γ) often used in clinical research and practice because of its bioactivity, for example, antivirus, antitumor, controlling cell apoptosis, and the strict selectivity. However, due to the difficulties of Escherichia coli expression system meet in protein folding, the hIFN-γ often existed as inclusion body. The production of soluble hIFN-γ can be developed to shorten the production cycle and decrease the cost. In this study, small ubiquitin-related modifier fusion technology was used to express and purify recombinant hIFN-γ. Expression induced by adding 50 mM arginine and 1 % (w/v) glycerol into the culture at 24 °C existed as a soluble form of 70 % in total protein. Finally, about 62 mg recombinant hIFN-γ was obtained from 1 L fermentation culture with no less than 96 % purity. Determined by cytopathic effect inhibition assay, the specific activity of the recombinant hIFN-γ achieved at 7.78 × 10⁵ IU/mL.     

Responses of a rice–wheat rotation agroecosystem to experimental warming

Climate change is likely to affect agroecosystems in many ways. This study was performed to investigate how a rice–winter wheat rotation agroecosystem in southeast China would respond to global warming. By using an infrared heater system, the soil surface temperature was maintained about 1.5 °C above ambient milieu over 3 years. In the third growing season (2009–2010), the evapotranspiration (ET) rate, crop production, soil respiration, and soil carbon pool were monitored. The ET rate was 23 % higher in the warmed plot as compared to the control plot during the rice paddy growing season, and the rice grain yield was 16.3 % lower, but there was no significant difference in these parameters between the plots during the winter wheat-growing season. The phenology of the winter wheat shifted under experimental warming, and ET may decrease late in the winter wheat-growing season. Experimental warming significantly enhanced soil respiration, with mean annual soil respiration rates of 2.57 ± 0.17 and 1.96 ± 0.06 μmol CO₂ m^?2 s^?1 observed in the warmed and control plots, respectively. After 3 years of warming, a significant decrease in the total organic carbon was observed, but only in the surface soil (0–5 cm). Warming also stimulated the belowground biomass, which may have compensated for any heat-induced loss of soil organic carbon. Paddy rice seemed to be more vulnerable to warming than winter wheat in terms of water-use efficiency and grain production.     

Studies on the Phenylphenol Derivatives with Biological Activity

More than ninety phenylphenol derivatives were tested for fungistatic activity toward ten species of agriculturally important fungi. One of N-methylcarbamates and some nitro- or chloro-substituted derivatives were highly toxic against Piricularia oryzae. From the relationship between the chemical structure and the activity, it is supposed that the reactivity, the permeability, the steric effect and the metabolic activation of the compound are the responsible factors for the fungistatic activity.