Molecular Cloning and Characterizations of Xylanase Inhibitor Protein from Wheat (Triticum Aestivum).

Xylanase inhibitor proteins (XIPs) were regarded to inhibit the activity of xylanases during baking and gluten-starch separation processes. To avoid the inhibition to xylanases, it is necessary to define the conditions under which the inhibition takes place. In this study, we cloned the XIP gene from 2 different variety of Triticum aestivum, that is, Zhengmai 9023 and Zhengmai 366, and investigated the properties of XIP protein expressed by Pichia pastoris. The results showed that the 2 XIP genes (xip-9023 and xip-366) were highly homologous with only 3 nucleotide differences. XIP-9023 showed the optimal inhibition pH and temperature were 7 °C and 40 °C, respectively. Inhibition of xylanase by XIP-9023 reached the maximum in 40 min. At 50% inhibition of xylanase, the molar ratio of inhibitor: xylanase was 26:1. XIP-9023 was active to various fungal xylanases tested as well as to a bacterial xylanase produced by Paenibacillus sp. isolated from cow rumen.

Antitumor Compounds from the Stout Camphor Mushroom Taiwanofungus camphoratus (Higher Basidiomycetes) Spent Culture Broth.

A known compound, 5-(hydroxymethyl) furan-2-carbaldehyde, and a novel compound, 3-isobutyl-1-methoxy-4-(4'-(3-methylbut-2-enyloxy)phenyl)-1H-pyrrole-2,5-dione were isolated from spent broth from submerged cultures of Taiwanofungus camphoratus. Their structures were elucidated by nuclear magnetic resonance (1H, 13C, and 2D) and mass spectra. These compounds inhibited the proliferation of K562 and HepG2 tumor cells in vitro.

Immobilization of Aspergillus niger xylanase on chitosan using dialdehyde starch as a coupling agent.

Dialdehyde starch (DAS) was used as a novel coupling agent to prepare chitosan carrier to immobilize the xylanase from Aspergillus niger A-25. Compared with glutaraldehyde-cross-linked chitosan (CS-GA) and pure chitosan beads, the DAS-cross-linked chitosan (CS-DAS) beads exhibited the highest xylanase activity recovery. The DAS adding amount and cross-linking time in CS-DAS preparation process were optimized with respect to activity recovery to the values of 1.0 g (6.7% w/v concentration) and 16 h, respectively. The optimum temperature of both the CS-DAS- and CS-GA-immobilized xylanase was observed to be 5 degrees C higher than that of free enzyme (50 degrees C). The CS-DAS-immobilized xylanase had the highest thermal and storage stability as compared to the CS-GA-immobilized and free xylanase. The apparent K (m) and V (max) values of the CS-DAS-immobilized xylanase were estimated to be 1.29 mg/ml and 300.7 mumol/min/mg protein, respectively. The CS-DAS-immobilized xylanase could produce from birchwood xylan high-quality xylo-oligosaccharides, mainly composed of xylotriose, as free xylanase did. The proposed CS-DAS carrier was more advantageous over the CS-GA or pure chitosan carrier for xylanase immobilization application.

[Degradation of soil phenolic acids by Phanerochaete chrysosporium under continuous cropping of cucumber].

With inoculation of Phanerochaete chrysosporium in shaking flask, this paper studied the degradation of soil p-hydroxybenzoic acid, vanillic acid and ferulic acid under continuous cropping of cucumber, and evaluated the effect of this inoculation in overcoming the continuous cropping obstacle of cucumber. The results showed that after 8 days of inoculation, more than 99% of soil phenolic acids were decomposed by P. chrysosporium. Compared with the control, the contents of soil phenolic acids under 7 years continuous cropping of cucumber declined, with a degradation rate of 54.46%. After inoculating P. chrysosporium, soil fungal population and the plant height, stem width, and fresh and dry mass of cucumber had less change, but the occurrence of cucumber root diseases reduced greatly, with the relative disease index of wilt and root knot nematode declined by 10.2% and 14.6%, respectively. It was suggested that inoculation of P. chrysosporium had definite effect in overcoming the continuous cropping obstacle of cucumber.

[Improved culturability of soil bacteria using proper combination with various culturing medium].

To isolate more unique and previously unrecognized bacteria in soil samples, the culture difference under three incubation modes was investigated by using trophic, low-nutrient broth and soil extract as growth medium. Plate count proved that the oligotrophic medium resulted in a slow growth and consecutive colony formation over the course of incubation. On the 5th day, the most number of colony-forming unit was found on trophic LB and low-nutrient R2A, which was approximate 5 times as many as that isolated on 0.1 x LB. Of the 7 media, LB broth harvested the maximum bacterial communities, and novel species could be isolated as the nutrient was diluted to appropriate extent. The DGGE patterns of oligotrophic and rich nutrient culture collection displayed low similarity, however, the bands at various lanes exhibited complementary effect. When cultivated with static flask, LB and R2A media obtained more bacterial species, which concluded most species isolated by the other five media. Under the test tube incubation mode, the most species was also found in LB medium except some appeared only on R2A and TSB. Apparent bacterial communities difference could be detected between R2A, LB and TSB media. The experiment data may contribute much to the special medium design as well as improvement of bacterial culturability by using proper medium.