Chaetoglobosin A is an antibacterial compound produced by Chaetomium globosum, with potential application as a biopesticide and cancer treatment drug. The aim of this study was to evaluate the feasibility of utilizing cornstalks to produce chaetoglobosin A by C. globosum W7 in solid-batch fermentation and to determine an optimal method for purification of the products. The output of chaetoglobosin A from the cornstalks was 0.34 mg/g, and its content in the crude extract was 4.80%. Purification conditions were optimized to increase the content of chaetoglobosin A in the crude extract, including the extract solvent, temperature, and pH value. The optimum process conditions were found to be acetone as the extractant, under room temperature, and at a pH value of 13. Under these conditions, a production process of the antifungal chaetoglobosin A was established, and the content reached 19.17%. Through further verification, cornstalks could replace crops for the production of chaetoglobosin A using this new production process. Moreover, the purified products showed great inhibition against Rhizoctonia solani, with chaetoglobosin A confirmed as the main effective constituent (IC50 = 3.88 μg/mL). Collectively, these results demonstrate the feasibility of using cornstalks to synthesize chaetoglobosin A and that the production process established in this study was effective.

In this study we investigated the use of a crude enzyme extract from Trichoderma viride to hydrolyze wheat straw for butanol production by Clostridium acetobutylicum ATCC824. Prior to fermentation, the wheat straw was hydrolyzed by the crude enzyme at the optimized conditions of 50.7 °C, pH 5.1, 41.1 IU/g cellulase dosage, and 38.1 g/L substrate concentration, in which the sugar yield was 17.32 g/L, resulting in a 82.2% saccharification efficiency of commercial cellulase. The final butanol concentration, yield, and maximum productivity, 7.05 g/L, 0.155 g/g of glucose, and 0.141 g/L·h, were observed in separated hydrolysis and fermentation after 54 h of fermentation using 2-fold concentrated hydrolysate. Simultaneous saccharification and fermentation was also investigated, and appreciable butanol concentration, yield, and productivity of 5.05 g/L, 0.127 g/g of glucose, and 0.080 g/L·h were attained. The results described here are comparable to those obtained by using commercial cellulase and clearly indicate the potential application of crude cellulase for enhanced butanol production from lignocellulose.

Liver metastasis is the major obstacle for prolonging the survival of colon cancer patients. Low-molecular-weight heparin (LMWH), a common drug for venous thromboembolism, has displayed beneficial effects in improving the survival of cancer patients, though the mechanism remains unclear. This study aimed to investigate the effects of LMWH on hepatic metastasis of colon cancer and its underlying molecular mechanism by targeting the interaction of the chemokine receptor CXCR4 and its ligand CXCL12 (formerly known as stromal cell-derived factor 1α, SDF-1α), as the CXCR4-CXCL12 axis has been shown to regulate the interaction of cancer cells and stroma. Experimental results revealed that LMWH (Enoxaparin, 3500–5500 Da) inhibited the CXCL12-stimulated proliferation, adhesion and colony formation of human colon cancer HCT-116 cells that highly expressed CXCR4. Interestingly, LMWH or an anti-CXCR4 blocking antibody diminished the migrating and invading abilities of HCT116 cells stimulated by the recombinant CXCL12 protein or liver homogenates which contained endogenous CXCL12 protein. Although LMWH did not significantly inhibit the growth of subcutaneous colon tumors, it significantly suppressed the formation of hepatic metastasis established by intrasplenic injection of colon cancer cells in nude Balb/c mice and also downregulated the expression of CXCL12 in hepatic sinusoidal endothelial cells. The results suggest that LMWH inhibits the formation of hepatic metastasis of colon cancer by disrupting the interaction of CXCR4 and CXCL12, supporting that perioperative administration of LMWH may help to prevent the seeding and subsequent growth of hepatic metastases of colon cancer cells.

A moderately halophilic bacterial strain 15-13T, which was isolated from soda meadow saline soil in Daqing City, Heilongjiang Province, China, was subjected to a polyphasic taxonomic study. The cells of strain 15–13 were found to be Gram-negative, rod-shaped, and motile. The required growth conditions for strain 15–13T were: 1–23% NaCl (optimum, 7%), 10–50°C (optimum, 35°C), and pH 7.0–11.0 (optimum, pH 9.5). The predominant cellular fatty acids were C18:1ω7c (60.48%) and C16:0 (13.96%). The DNA G+C content was 67.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequence comparisons indicated that strain 15–13T clustered within a branch comprising species of the genus Halomonas. The closest phylogenetic neighbor of strain 15–13T was Halomonas pantelleriensis DSM 9661T (98.9% 16S rRNA gene sequence similarity). The level of DNA-DNA relatedness between the novel isolated strain and H pantelleriensis DSM 9661T was 33.8%. On the basis of the phenotypic and phylogenetic data, strain 15–13T represents a novel species of the genus Halomonas, for which the name Halomonas alkalitolerans sp. nov. is proposed. The type strain for this novel species is 15–13T (=CGMCC 1.9129T =NBRC 106539T).

Endoglucanase is a major cellulolytic enzyme produced by the fungus Trichoderma viride. The 1,317 bp cDNA of endoglucanase gene egVIII was cloned from T. viride AS3.3711, encoding a 438 amino acid protein with a calculated molecular mass of 46.86 kDa and isoelectric point of 4.32. Sequence analysis suggested that EGVIII belonged to the glycosyl hydrolase family 5. The N-terminal region of EGVIII contains a signal peptide sequence of 19 amino acid residues, indicating that it is an extracellular enzyme. Transcription of the egVIII gene in T. viride AS3.3711 can be induced by carboxymethyl cellulose sodium (CMC-Na), sucrose, microcrystalline cellulose, and corn stalk, and inhibited by glucose and fructose. The α-mating factor signal can effectively enhance the secretion of the recombinant EGVIII in Saccharomyces cerevisiae, as demonstrated by the enzymatic activity of recombinant yeast IpYEMα-xegVIII in the supernatant, which was 0.86 times higher than that of the IpYES2-egVIII. Recombinant endoglucanase EGVIII showed optimal activity at a temperature of 60°C and pH of 6.0. It was stable when incubated from 35°C to 70°C for 1 h. The enzymatic activity of recombinant EGVIII was stable at a pH 3.0 to 7.5 at 50°C and reached the highest level at 0.174U when activated by 75 mM of Zn2+. The Michaelis–Menten constant (Km) and Kcat values for CMC-Na and cellotriose hydrolysis were 3.82 mg/ml, 9.56 s−1 and 1.75 mg/ml, 7.08 s−1, respectively. Transgenic yeast strain IpYEMα-xegVIII might be useful for renewable fuels industries.

An antifungal protein was isolated from a culture of Bacillus subtilis strain B29. The isolation procedure comprised ion exchange chromatography on diethylaminoethyl (DEAE)-52 cellulose and gel filtration chromatography on Bio-Gel® P-100. The protein was absorbed on DEAE-cellulose and Bio-Gel® P-100. The purified antifungal fraction was designated as B29I, with a molecular mass of 42.3 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), pI value 5.69 by isoelectric focusing (IEF)-PAGE, and 97.81% purity by high performance liquid chromatography (HPLC). B29I exhibited inhibitory activity on mycelial growth in Fusarium oxysporum, Rhizoctonia solani, Fusarium moniliforme, and Sclerotinia sclerotiorum. The 50% inhibitory concentrations (IC50) of its antifungal activity toward Fusarium oxysporum and Rhizoctonia solani were 45 and 112 μmol/L, respectively. B29I also demonstrated an inhibitory effect on conidial spore germination of Fusarium oxysporum and suppression of germ-tube elongation, and induced distortion, tumescence, and rupture of a portion of the germinated spores.

The purpose of this study is to investigate the function of a novel potassium transporter gene (NrHAK1) isolated from Nicotiana rustica roots using yeast complement and real-time PCR technique. The complementary DNA (cDNA) of NrHAK1, 2 488 bp long, contains an open reading frame (ORF) of 2 334 bp encoding a protein of 777 amino acids (87.6 kDa) with 12 predicted transmembrane domains. The NrHAK1 protein shows a high sequence similarity to those of high-affinity potassium transporters in Mesembryanthemum, Phytolacca acinosa, Arabidopsis thaliana, and so on. We found that the NrHAK1 gene could complement the yeast-mutant defect in K+ uptake. Among several tissues surveyed, the expression level of NrHAK1 was most abundant in the root tip and was up-regulated when exposed to potassium starvation. Moreover, the transcript accumulation was significantly reduced by adding 5 mmol/L NH4+ to the solution. These results suggest that NrHAK1 plays an important role in potassium absorption in N. rustica.

Chitinases play a major role in the defensive strategies of plants against fungal pathogens. In the current study, the gene for a 46-kDa endochitinase (chi46) was cloned from Chaetomium globosum, an important biocontrol fungus. The corresponding complementary deoxyribonucleic acid sequence was 1,350 bp in length, encoding 449 amino acid residues. The temporal expression of chi46, in response to the treatments of cell walls of six pathogens and confrontation against two fungal pathogens, was measured in C. globosum using real-time reverse transcription polymerase chain reaction. The expression of chi46 can be highly induced by exposure to the cell walls of plant pathogens and living pathogens, suggesting a role in plant disease resistance. The chi46 gene was inserted into the pPIC9 vector and transferred into the cells of Pichia pastoris GS115 for heterologous expression. The optimal reaction conditions for chitinase CHI46 activity were: 45°C, pH of 5.0, and 5 mmol l−1 of Cu2+. The maximum enzyme activity was 1.42 U ml−1 following exposure to the cell wall chitin of Septoria tritici. The CHI46 enzyme can efficiently degrade cell walls of the phytopathogenic Rhizoctonia solani, Fusarium oxysporum, Sclerotinia sclerotiorum, Valsa sordida, S. tritici, and Phytophthora sojae, demonstrating that it may be involved in the biocontrol mechanism of C. globosum.

A small heat shock protein gene (hsp22.4) was cloned from Chaetomium globosum using rapid amplification of cDNA ends (RACE). The 986-bp full-length hsp22.4 cDNA contains a 609-bp open reading frame encoding a 202-amino-acid protein with an estimated molecular mass of 22.4 kDa. The hsp22.4 gene was amplified using specific primers in the 5′ and 3′ untranslated regions of the hsp22.4 cDNA. The temporal expression of hsp22.4 was measured in C. globosum by real-time reverse transcriptase-polymerase chain reaction after exposure to heat, cold, Na2CO3, and NaCl. The expression of hsp22.4 was induced by heat and Na2CO3 treatment and inhibited by cold and NaCl treatment. The hsp22.4 gene was inserted into pYES2 containing the inducible GAL1 promoter and transferred into yeast (Saccharomyces cerevisiae) for expression. The hsp22.4 transgenic yeast displayed significantly greater resistance to heat and Na2CO3 stresses than control (yeast cells transformed with empty pYES2), suggesting that the expression of hsp22.4 gene confers not only heat tolerance but also significant alkali (Na2CO3) stress tolerance.