Expression of L-amino acid oxidase of Trichoderma harzianum in tobacco confers resistance to Sclerotinia sclerotiorum and Botrytis cinerea.

L-amino acid oxidase (ThLAAO) secreted by Trichoderma harzianum ETS323 is a flavoenzyme with antimicrobial characteristics. In this study, we transformed the ThLAAO gene into tobacco to elucidate whether ThLAAO can activate defense mechanisms and confer resistance against phytopathogens. Transgenic tobacco overexpressing ThLAAO showed enhanced resistance against Sclerotinia sclerotiorum and Botrytis cinerea and activated the expression of defense-related genes and the genes involved in salicylic acid, jasmonic acid, and ethylene biosynthesis accompanied by substantial accumulation of H2O2 in chloroplasts, cytosol around chloroplasts, and cell membranes of transgenic tobacco. Scavenge of H2O2 with ascorbic acid abolished disease resistance against B. cinerea infection and decreased the expression of defense-related genes. ThLAAO-FITC application on tobacco protoplast or overexpression of ThLAAO-GFP in tobacco revealed the localization of ThLAAO in chloroplasts. Chlorophyll a/b binding protein (CAB) was isolated through ThLAAO-ConA affinity chromatography. The pull down assay results confirmed ThLAAO-CAB binding. Application of ThLAAO-Cy5.5 on cabbage roots promptly translocated to the leaves. Treatment of ThLAAO on cabbage roots induces systemic resistance against B. cinerea. Overall, these results demonstrate that ThLAAO may target chloroplast and activate defense mechanisms via H2O2 signaling to confer resistance against S. sclerotiorum and B. cinerea.

Gene-to-Gene Network Analysis of the Mediation of Plant Innate Immunity by the Eliciting Plant Response-Like 1 (Epl1) Elicitor of Trichoderma formosa.

A new clade, Trichoderma formosa, secretes eliciting plant response-like 1 (Epl1), a small peptide elicitor that stimulates plant immunity. Nicotiana benthamiana pretreated with Epl1 for 3 days developed immunity against Tomato mosaic virus (ToMV) infection. The transcriptome profiles of T. formosa and N. benthamiana were obtained by deep sequencing; the transcript of Epl1 is 736 nt in length and encodes a 12-kDa peptide. Identifying critical genes in Epl1-mediated immunity was challenging due to high similarity between the transcriptome expression profiles of Epl1-treated and ToMV-infected N. benthamiana samples. Therefore, an efficient bioinformatics data mining approach was used for high-throughput transcriptomic assays in this study. We integrated gene-to-gene network analysis into the ContigViews transcriptome database, and genes related to jasmonic acid and ethylene signaling, salicylic acid signaling, leucine-rich repeats, transcription factors, and histone variants were hubs in the gene-to-gene networks. In this study, the Epl1 of T. formosa triggers plant immunity against various pathogen infections. Moreover, we demonstrated that high-throughput data mining and gene-to-gene network analysis can be used to identify critical candidate genes for further studies on the mechanisms of plant immunity.

Anticancer activity of Kalanchoe tubiflora extract against human lung cancer cells in vitro and in vivo.

Uncontrolled cell proliferation is a common feature of human cancer. Some of herbal extract or plant-derived medicine had been shown as an important source of effective anticancer agents. We previously reported that an n-BuOH-soluble fraction of Kalanchoe tubiflora has antiproliferative activity by inducing mitotic catastrophe. In this study, we showed that the H2 O-soluble fraction of Kalanchoe tubiflora (KT-W) caused cell cycle arrest, and senescence-inducing activities in A549 cells. We used 2 dimensional PAGE to analyze the protein expression levels after KT-W treatment, and identified that the energy metabolism-related proteins and senescence-related proteins were disturbed. In vivo experiments showed that the tumor growths in A549-xenografted nude mice were effectively inhibited by KT-W. Our findings implied that KT-W is a putative antitumor agent by inducing cell cycle arrest and senescence. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1663-1673, 2016.

Euphorbia formosana root extract induces apoptosis by caspase-dependent cell death via Fas and mitochondrial pathway in THP-1 human leukemic cells.

Acute myeloid leukemia (AML), a very rare type of cancer, generally affects patients over 50 years old. While clinical drugs to treat advanced stages of AML exist, the disease becomes increasingly resistant to therapies. Euphorbia formosana Hayata (EF) is a native Taiwanese medicinal plant used to treat rheumatism, liver cirrhosis, herpes zoster, scabies, and photoaging, along with tumor suppression. However, the mechanisms by which it suppresses tumors have not been explored. Here, we provide molecular evidence that a hot-water extract of Euphorbia formosana (EFW) selectively inhibited the growth of human leukemic cancer cells more than other solid human cancer cell lines. Most importantly, the plant extract had limited toxicity toward healthy peripheral blood mononuclear cells (PBMCs). After THP-1 leukemic cells were treated with 50-100 µg/mL EFW for one day, the S phase DNA content of the cells increased, while treatment with 200-400 µg/mL caused the cells to accumulate in the G0/G1 phase. Notably, EFW did not affect A-549 lung cancer cells. The effectiveness of EFW against THP-1 cells may be through caspase-dependent apoptosis in leukemic cells, which is mediated through the Fas and mitochondrial pathways. The potent antileukemic activity of EFW in vitro warrants further investigation of this plant to treat leukemias and other malignancies.

Antagonism of Trichoderma harzianum ETS 323 on Botrytis cinerea mycelium in culture conditions.

ABSTRACT Previous studies have shown that the extracellular proteins of Trichoderma harzianum ETS 323 grown in the presence of deactivated Botrytis cinerea in culture include a putative l-amino acid oxidase and have suggested the involvement of this enzyme in the antagonistic mechanism. Here, we hypothesized that the mycoparasitic process of Trichoderma spp. against B. cinerea involves two steps; that is, an initial hyphal coiling stage and a subsequent hyphal coiling stage, with different coiling rates. The two-step antagonism of T. harzianum ETS 323 against B. cinerea during the mycoparasitic process in culture was evaluated using a biexponential equation. In addition, an l-amino acid oxidase (Th-l-AAO) was identified from T. harzianum ETS 323. The secretion of Th-l-AAO was increased when T. harzianum ETS 323 was grown with deactivated hyphae of B. cinerea. Moreover, in vitro assays indicated that Th-l-AAO effectively inhibited B. cinerea hyphal growth, caused cytosolic vacuolization in the hyphae, and led to hyphal lysis. Th-l-AAO also showed disease control against the development of B. cinerea on postharvest apple fruit and tobacco leaves. Furthermore, an apoptosis-like response, including the generation of reactive oxygen species, was observed in B. cinerea after treatment with Th-l-AAO, suggesting that Th-l-AAO triggers programmed cell death in B. cinerea. This may be associated with the two-step antagonism of T. harzianum ETS 323 against B. cinerea.

Involvement of pachybasin and emodin in self-regulation of Trichoderma harzianum mycoparasitic coiling.

Our aim was to determine the effects of two secondary metabolites secreted by Trichoderma harzianum, pachybasin and emodin, on the mycoparasitic coiling behavior and cAMP content of T. harzianum. The number of T. harzianum coils around Nylon 66 fiber was increased in the presence of R. solani. The number of T. harzianum coils around R. solani hyphae and Nylon 66 fiber were significantly increased in the presence of pachybasin and emodin. The cAMP level in T. harzianum was significantly increased by close contact with R. solani and much higer cAMP level in the presence of exogenous pachybasin and emodin. A cAMP inhibitor diminished the effect of pachybasin and emodin on T. harzianum coiling around Nylon 66 fiber. The results suggest that pachybasin and emodin mediate the increase in the number of Trichoderma mycoparasitic coils via cAMP signaling. This is the first report to suggest that pachybasin and emodin play roles in the biocontrol mechanism of Trichoderma.

Preferential promotion of apoptosis of monocytes by Lactobacillus casei rhamnosus soluble factors.

BACKGROUND & AIMS: Inflammatory bowel disease (IBD) is characterized by dense infiltrates of and defective apoptosis by mucosal cell populations. Some probiotics inhibit monocytes' expansion, although mechanisms remain unknown. Supernatants of Lactobacillus strains were investigated for inducing apoptosis of monocytes. METHODS: Secreted factors produced by Lactobacillus strains were tested on human lymphocytes, monocytes and a human monocytic leukemia-cell line (THP-1). Cell death mechanisms were investigated by a variety of methods. Lipopolysaccharide (LPS)-induced proinflammatory cytokines (IL-1beta, IL-6, IL-8, TNF-alpha) and anti-inflammatory TGF-beta1 were determined. RESULTS: Soluble factor(s) from Lactobacillus casei rhamnosus strain supernatants (LcrS) effectively induced apoptosis of immune cells. These were mainly soluble proteins (MW 5-30 kDa; LcrS(5-30)). For immune cells, but not human colonic epithelial carcinoma cells (HT-29), pretreatment with LcrS(5-30) significantly promoted apoptosis via a mitochondrial pathway. LcrS(5-30) suppressed pro-inflammatory cytokines and induced anti-inflammatory TGF-beta1. CONCLUSIONS: Probiotic Lcr produced heat-stable molecules (MW range 5-30 kDa) that promoted immune cell apoptosis without affecting intestinal epithelial cells. LcrS(5-30) triggered apoptosis by a mitochondrial pathway, but not via TGF-beta signaling pathway. LcrS(5-30) also inhibited LPS-induced inflammatory cytokines by immune cells. Thus, LcrS(5-30) promotes apoptosis of immune cells, and suggests probiotics-based regimens for prevention of IBD.

Piezoelectric immunochip for the detection of dengue fever in viremia phase.

The global prevalence of dengue fever has grown so dramatically in recent years that it is endemic in more than 100 countries and has become a major international public health concern. Moreover, since the flu-like symptoms that accompany dengue fever are atypical and varied, the detection procedures currently used to identify it are cumbersome and time-consuming, making early stage epidemiological control and effective medical treatment of this epidemic almost impossible. In this study, a QCM-based detection system was developed in which two monoclonal antibodies against dengue E and NS-1 protein, respectively, were control orientated immobilized on QCM via protein A to produce an immunochip. Various sample pretreatment procedures were evaluated to ascertain the most suitable combination, and both the simulating samples and the clinical specimen were examined by the immunochip. The results revealed that the cibacron blue 3GA gel-heat denature (CB-HD) method was the most effective sample pretreatment technique. Due to the complex composition of the serum, the immunochip could only effectively quantify dengue viral antigens in a 1/1000 untreated simulated sample. With the help of the CB-HD method, the dilution folds were found to capable of being reduced from 1000 to 100, and the detection limit lowered to 1.727 microg/ml (E protein) and 0.740 microg/ml (NS-1 protein) in the original sample. While the cocktail immunochip could not quantify both antigens separately, the higher signal level rendered it a more effective qualification tool for suspect screening. Moreover, the results of the analysis of clinical specimens also proved the ability and future potential of cocktail immunochip in discriminating dengue-positive cases from negative serum specimens in the viremia phase.

Circular dichroism analysis of destruxins from Metarhizium anisopliae.

Destruxins are secondary metabolites secreted by Metarhizium anisopliae [Y. Kodaira, Toxic substances to insects, produced by Aspergillus ochraceus and Oopsra destructor, Agric. Biol. Chem., 25 (1961) 261-262. D.W. Roberts, Toxins from the entomogenous fungus Metarhizium anisoplaie: Isolation from submerged cultures, J. Invertebr. Pathol., 14 (1969) 82-88. D.W. Roberts, Toxins from the entomogenic fungi in microbial control of pest and plant disease, Academic press, New York, 1981, pp441-464.]. In recent research, other than being used as insecticides, destruxins exhibited great potential in therapeutical applications such as antitumor, antivirus, and animal cell immunization effectiveness, etc. In this study, the conformations purified destruxins were determined by circular dichroism (CD). The results indicated that these cyclic peptides have the type I beta-turn conformation. In addition, different types of destruxins exhibited different CD spectra in acetonitrile. Therefore, these characters can be used as fingerprints to identify each type of destruxin. To further investigate the interactions among destruxins, various combinations of destruxins in 10 mM phosphate-buffered saline (PBS) were also studied by CD. The results strongly suggested that destruxins might work independently in vivo. To our knowledge, this is the first report presenting the CD analysis of purified destruxins.