Salecan Enhances the Activities of β-1,3-Glucanase and Decreases the Biomass of Soil-Borne Fungi

<div><p>Salecan, a linear extracellular polysaccharide consisting of β-1,3-D-glucan, has potential applications in the food, pharmaceutical and cosmetic industries. The objective of this study was to evaluate the effects of salecan on soil microbial communities in a vegetable patch. Compositional shifts in the genetic structure of indigenous soil bacterial and fungal communities were monitored using culture-dependent dilution plating, culture-independent PCR-denaturing gradient gel electrophoresis (DGGE) and quantitative PCR. After 60 days, soil microorganism counts showed no significant variation in bacterial density and a marked decrease in the numbers of fungi. The DGGE profiles revealed that salecan changed the composition of the microbial community in soil by increasing the amount of <i>Bacillus</i> strains and decreasing the amount of <i>Fusarium</i> strains. Quantitative PCR confirmed that the populations of the soil-borne fungi <i>Fusarium oxysporum</i> and <i>Trichoderma</i> spp. were decreased approximately 6- and 2-fold, respectively, in soil containing salecan. This decrease in the amount of fungi can be explained by salecan inducing an increase in the activities of β-1,3-glucanase in the soil. These results suggest the promising application of salecan for biological control of pathogens of soil-borne fungi.</p></div

Profiles of reconstruction results.

<p>Reconstruction profiles through the marked lines in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0138483#pone.0138483.g005" target="_blank">Fig 5</a> containing large hot features. Note that all data have been normalized.</p

Flowchart of the proposed methods.

<p>It is illustrated for the introduction of total variation before 2D inverse FFT procedure of traditional direct Fourier method.</p

The principle of a rebinning algorithm.

<p>For multiring scanners, the oblique sinograms by 3D acquisition can be rebinned to several ordinary sinograms of N direct slices lying in the plane of the N detector and N-1 cross slices lying between adjacent detector rings.</p

Selected area of reconstructed results.

<p>Each row shows results using one slice of data, left: reference image with red rectangle indicating the zoomed-in box for comparison, middle: the zoomed-in boxes reconstructed with DF, right: the zoomed-in boxes reconstructed with BOSVS. From up to down, the slice of data is 19th, 27th, 35th and 43th slice.</p

Changes in soil bacteria community structure.

<p>(a) Bacterial colony-forming units assessed using the culture plating method. All values are the means ± SD (n = 3). (b) Similarity dendrogram of the bacterial banding patterns of soil samples. The scale for 0.44–1.00 was the similarity coefficient among the samples. DGGE fingerprints of 16S rDNA sequences amplified using the primer pair 357fGC/518r from soil-extracted community DNA. Lanes 1, 2 and 3 show the results of soil samples without salecan treatment (C); lanes 4, 5 and 6 show the results of 0.02% salecan-treated samples; and lanes 7, 8 and 9 show the results of 0.2% salecan-treated samples. Seven changed DGGE bands (B1, B2, B3, B4, B5, B6, B7) are marked by arrows. (c) The phylogenetic relationship between the 16S rRNA gene sequences of the soil samples and the related organisms from the GenBank database. The dendrogram was generated using the neighbor-joining method, with 1000 bootstrap resamplings. The scale bar represented 0.02, estimated nucleotide changes per sequence position.</p

Reconstructed results of the center slice.

<p>A central transaxial slice from (A) brain phantom data, (B) zubal phantom data. Left: the ground truth. Middle: reconstructed with DF. Right: reconstructed with BOSVS.</p

Image reconstruction with DF and BOSVS using four slices of CTI ECAT data.

<p>The upper row represents the results achieved from DF, while the bottom represents the results of BOSVS. From left to right, the slice of data is 19th, 27th, 35th and 43th slice.</p

The chemical structure of the repeated unit of salecan.

<p>The chemical structure of the repeated unit of salecan.</p

PCR primers and targeted microorganisms used in this study.

<p>^a Primers with a 40-bp GC clamp at the 5’ end.</p><p>^b Q-PCR primers.</p><p>PCR primers and targeted microorganisms used in this study.</p