Manufacture and antibacterial characteristics of Eucommia ulmoides leaves vinegar.

In this work, the fermentation conditions and the antibacterial characteristics of Eucommia ulmoides leaves vinegar (EV) were studied. By single factor orthogonal test, it was found that under optimal fermentation conditions (bran addition 10%, sugar addition 8%, leaven addition 0.3% and acetic acid bacteria solution 12%), the acetic acid content and CA content of EV were 45.5 ± 2.8 mg/mL and 0.98 ± 0.08 mg/mL, respectively. Then, by the disc diffusion method, it was concluded that the antibacterial effect of EV was significantly higher than that of Eucommia ulmoides leaves enzymatic hydrolysate and Zhenjiang aromatic vinegar (P<0.05). An investigation into action mode of EV against Bacillus subtilis indicated that, under the combined action of CA and acetic acid, EV exerted its antibacterial effect by damaging bacterial cell wall and cell membrane, increasing the cell permeability which resulted in the structural lesions and release of cell components, thus led to cell death.

A thermostable Gloeophyllum trabeum xylanase with potential for the brewing industry.

A xylanase gene of glycoside hydrolase family 10, GtXyn10, was cloned from Gloeophyllum trabeum CBS 900.73 and expressed in Pichia pastoris GS115. Purified recombinant GtXyn10 exhibited significant activities to xylan (100.0%), lichenan (11.2%), glucan (15.2%) and p-nitrophenol-ß-cellobiose (18.6%), demonstrated the maximum xylanase and glucanase activities at pH 4.5-5.0 and 75°C, retained stability over the pH range of 2.0-7.5 and at 70°C, and was resistant to pepsin and trypsin, most metal ions and SDS. Multiple sequence alignment and modeled-structure analysis identified a unique Gly48 in GtXyn10, and site-directed mutagenesis of Gly48 to Lys improved the temperature optimum up to 80°C. Under simulated mashing conditions, GtXyn10 (80U) reduced the mash viscosity by 12.8% and improved the filtration rate by 31.3%. All these properties above make GtXyn10 attractive for potential applications in the feed and brewing industries.

Application of a novel alkali-tolerant thermostable DyP-type peroxidase from Saccharomonospora viridis DSM 43017 in biobleaching of eucalyptus kraft pulp.

Saccharomonospora viridis is a thermophilic actinomycete that may have biotechnological applications because of its dye decolorizing activity, though the enzymatic oxidative system responsible for this activity remains elusive. Bioinformatic analysis revealed a DyP-type peroxidase gene in the genome of S. viridis DSM 43017 with sequence similarity to peroxidase from dye-decolorizing microbes. This gene, svidyp, consists of 1,215 bp encoding a polypeptide of 404 amino acids. The gene encoding SviDyP was cloned, heterologously expressed in Escherichia coli, and then purified. The recombinant protein could efficiently decolorize several triarylmethane dyes, anthraquinonic and azo dyes under neutral to alkaline conditions. The optimum pH and temperature for SviDyP was pH 7.0 and 70°C, respectively. Compared with other DyP-type peroxidases, SviDyP was more active at high temperatures, retaining>63% of its maximum activity at 50-80°C. It also showed broad pH adaptability (>35% activity at pH 4.0-9.0) and alkali-tolerance (>80% activity after incubation at pH 5-10 for 1 h at 37°C), and was highly thermostable (>60% activity after incubation at 70°C for 2 h at pH 7.0). SviDyP had an accelerated action during the biobleaching of eucalyptus kraft pulp, resulting in a 21.8% reduction in kappa number and an increase of 2.98% (ISO) in brightness. These favorable properties make SviDyP peroxidase a promising enzyme for use in the pulp and paper industries.

Analysis of miRNAs and their targets during adventitious shoot organogenesis of Acacia crassicarpa.

Organogenesis is an important process for plant regeneration by tissue or cell mass differentiation to regenerate a complete plant. MicroRNAs (miRNAs) play an essential role in regulating plant development by mediating target genes at transcriptional and post-transcriptional levels, but the diversity of miRNAs and their potential roles in organogenesis of Acacia crassicarpa have rarely been investigated. In this study, approximately 10 million sequence reads were obtained from a small RNA library, from which 189 conserved miRNAs from 57 miRNA families, and 7 novel miRNAs from 5 families, were identified from A. crassicarpa organogenetic tissues. Target prediction for these miRNAs yielded 237 potentially unique genes, of which 207 received target Gene Ontology annotations. On the basis of a bioinformatic analysis, one novel and 13 conserved miRNAs were selected to investigate their possible roles in A. crassicarpa organogenesis by qRT-PCR. The stage-specific expression patterns of the miRNAs provided information on their possible regulatory functions, including shoot bud formation, modulated function after transfer of the culture to light, and regulatory roles during induction of organogenesis. This study is the first to investigate miRNAs associated with A. crassicarpa organogenesis. The results provide a foundation for further characterization of miRNA expression profiles and roles in the regulation of diverse physiological pathways during adventitious shoot organogenesis of A. crassicarpa.