Echinococcosis Is Associated with the Increased Prevalence of Intestinal Blastocystis Infection in Tibetans and Host Susceptibility to the Blastocystis in Mice.

Blastocystis is a common human intestinal protozoan parasite. Little is known about its prevalence in echinococcosis. This study tested whether Echinococcus multilocularis infection would increase host susceptibility to Blastocystis. A total of 114 fecal samples (68 hydatid disease patients and 46 healthy people) were collected from Tibetans in the Qinghai province in China. The presence of Blastocystis was identified by sequencing of the small subunit (SSU) rRNA gene. Balb/c mice were co-infected with Blastocystis and E. multilocularis and tested for host susceptibility to Blastocystis. The overall Blastocystis prevalence was 12.3%; 16.2% in the patients and 4.4% in healthy people (p < 0.05). Sequence analysis identified three known Blastocystis genotypes, including ST1, ST2, and ST3, and one unknown genotype. Experimental dual infection significantly reduced mouse survival rate (20%), induced more severe signs, and increased intestinal damages with a higher intestinal colonization level of Blastocystis. The mouse model showed that E. multilocularis infection increases host susceptibility to Blastocystis. Our study shows a significantly higher prevalence of Blastocystis in patients with liver echinococcosis and reveals that non-intestinal E. multilocularis infection increases host susceptibility to the Blastocystis. Our results highlight that E. multilocularis infection is associated with Blastocystis. These findings remind us that more attention should be paid to the gut health of the patients with a helminth infection during clinical patient care.

[Mechanism of thymol inhibiting Botrytis cinerea: PAO-H2O2 system]. / éºé¦™è‰é šæŠ‘åˆ¶ç°éœ‰èŒçš„ä½œç”¨æœºç†: PAO-H2O2系统.

Gray mold disease caused by Botrytis cinerea infection is one of the major crop diseases. The application of environmental-friendly fungicides to control gray mold disease has been drawing great attention. Thymol, a natural compound, showed strong antifungal activity against Botrytis cinerea. We investigated the role of polyamine oxidase (PAO)-dependent hydrogen peroxide (H2O2) production in thymol-inhibited B. cinerea growth by using physiological and biochemical approaches. The results showed that: 1) Thymol significantly inhibited the growth of B. cinerea, with remarkable increases in H2O2 content, malondialdehyde (MDA) content, and PAO activity in mycelium. 2) Inhibition of PAO activity (addition of specific inhibitor MDL, N,N'-butanedienyl butanediamine) resulted in significant decreases in the contents of H2O2 and MDA as well as the partial recovery of mycelial growth under thymol treatment, suggesting that thymol might trigger PAO-dependent H2O2 accumulation resulting in oxidative injury and thus inhibit the growth of mycelium. 3) A PAO homologue gene BcPAO was cloned from B. cinerea. Multi-alignment combined with phylogenetic analysis showed that BcPAO protein had typical conserved domain of PAO family members. 4) Thymol at low concentrations did not affect the transcriptional level of BcPAO. However, the transcription of BcPAO was up-regulated remarkably by thymol at high concentration. This suggested that thymol-stimulated PAO activity may be resulted from the regulation of BcPAO. We conclude that oxidative injury caused by PAO-dependent H2O2 production is one of the possible antifungal modes of thymol against B. cinerea. The antifungal mode of thymol found in this study may provide basis for the application of environmental-friendly fungicides.

Thymol confers tolerance to salt stress by activating anti-oxidative defense and modulating Na+ homeostasis in rice root.

Modulation of plant salt tolerance has been drawing great attention. Thymol is a kind of natural chemical that has been developed as anti-microbial reagent and medicine. To date, we still have limited knowledge about thymol-modulated plant physiology. In this work, physiological, histochemical, and biochemical methods were adopted to study thymol-conferred salt resistance in the root of rice (Oryza sativa). Thymol significantly rescued root growth under salt stress. Thymol ameliorated cell membrane damage, oxidative stress, ROS accumulation, and cell death in roots under salt stress. Thymol-attenuated oxidative stress may be resulted from the activation of anti-oxidative capacity, including both enzymatic and non-enzymatic system. Thymol treatment significantly decreased Na+ content in root cells upon salt stress, which might be ascribed to the upregulation of OsSOS1 (salt overly sensitive 1) facilitating Na+ exclusion. In addition, thymol stimulated the expression of genes encoding tonoplast OsNHX (Na+/H+antiporter), which may help root cells to compartmentalize Na+ in vacuole. The results of these works evidenced that thymol was capable of inducing salt tolerance by reestablishing ROS homeostasis and modulating cellular Na+ flux in rice roots. These findings may be applicable to improve crop growth in salinity area.

Eugenol Confers Cadmium Tolerance via Intensifying Endogenous Hydrogen Sulfide Signaling in Brassica rapa.

Eugenol, a plant-derived small compound, shows great medicinal potential. However, whether and how eugenol regulates crop physiology remains elusive. Here we reported that eugenol induced Cd (cadmium) tolerance in the root of Brassica rapa. Roots were treated with eugenol and CdCl2 simultaneously (eugenol + Cd) or pretreated with eugenol followed by CdCl2 treatment (eugenol → Cd). Eugenol significantly attenuated Cd-induced growth inhibition, ROS accumulation, oxidative injury, and cell death, which were confirmed by in vivo histochemical analysis. Eugenol remarkably decreased free Cd2+ accumulation in root. Eugenol intensified GSH (glutathione) accumulation in roots upon CdCl2 exposure, which explained the decrease in free Cd2+ and attenuation of oxidative injury. Eugenol stimulated endogenous H2S (hydrogen sulfide) generation by upregulating the expression of BrLCD ( l-cysteine desulfhydrase) and BrDCD ( d-cysteine desulfhydrase) as well as their enzymatic activities in CdCl2-treated root. Application of H2S biosynthesis inhibitor or H2S scavenger led to the decrease in endogenous H2S level in Cd-treated root, which further compromised all the above effects of eugenol. These findings suggested that eugenol triggered H2S → GSH signaling cassette in plants to combat Cd stress, which shed new light on eugenol-modulated plant physiology and the interaction between eugenol and H2S.

Thymol Ameliorates Cadmium-Induced Phytotoxicity in the Root of Rice (Oryza sativa) Seedling by Decreasing Endogenous Nitric Oxide Generation.

Thymol has been developed as medicine and food preservative due to its immune-regulatory effect and antimicrobial activity, respectively. However, little is currently known about the role of thymol in the modulation of plant physiology. In the present study, we applied biochemical and histochemical approaches to investigate thymol-induced tolerance in rice (Oryza sativa) seedlings against Cd (cadmium) stress. Thymol at 20 µM recovered root growth completely upon CdCl2 exposure. Thymol pronouncedly decreased Cd-induced ROS accumulation, oxidative injury, cell death, and Cd2+ accumulation in roots. Pharmaceutical experiments suggested that endogenous NO mediated Cd-induced phytotoxicity. Thymol decreased Cd-induced NO accumulation by suppressing the activity of NOS (nitric oxide synthase) and NR (nitrate reductase) in root. The application of NO donor (SNP, sodium nitroprusside) resulted in the increase in endogenous NO level, which in turn compromised the alleviating effects of thymol on Cd toxicity. Such findings may helpful to illustrate the novel role of thymol in the modulation of plant physiology, which may be applicable to improve crop stress tolerance.

Inhibition of the Aspergillus flavus Growth and Aflatoxin B1 Contamination on Pistachio Nut by Fengycin and Surfactin-Producing Bacillus subtilis UTBSP1.

In this study, the treatment of pistachio nuts by Bacillus subtilis UTBSP1, a promising isolate to degrade aflatoxin B1 (AFB1), caused to reduce the growth of Aspergillus flavus R5 and AFB1 content on pistachio nuts. Fluorescence probes revealed that the cell free supernatant fluid from UTBSP1 affects spore viability considerably. Using high-performance liquid chromatographic (HPLC) method, 10 fractions were separated and collected from methanol extract of cell free supernatant fluid. Two fractions showed inhibition zones against A. flavus. Mass spectrometric analysis of the both antifungal fractions revealed a high similarity between these anti-A. flavus compounds and cyclic-lipopeptides of surfactin, and fengycin families. Coproduction of surfactin and fengycin acted in a synergistic manner and consequently caused a strong antifungal activity against A. flavus R5. There was a positive significant correlation between the reduction of A. flavus growth and the reduction of AFB1 contamination on pistachio nut by UTBSP1. The results indicated that fengycin and surfactin-producing B. subtilis UTBSP1 can potentially reduce A. flavus growth and AFB1 content in pistachio nut.

[Formulation Optimization of Zuojin Floating-Bioadhesive Pellets by Central Composite Design-Response Surface Methodology].

OBJECTIVE: To optimize the formulation of Zuojin floating-bioadhesive pellets by the central composite design-response surface methodology (CCD-RSM). METHODS: In the formulation design using CCD-RSM, independent variables were the amounts of sodium bicarbonate (X1), HPMC (X2) and MCC (X3) as factors. Small pills roundness, 12 h floating rate and the percentages of in vitro cumulative releases at 2,6 and 12 h were dependent variables. Multilinear and quadratic model were used to estimate the relationship between the dependent and the independent variables. According to best model, the contour plots and RSM were drawn, and the optional formulation was selected. According to the optional formulation,the pellets were prepared and validated. RESULTS: The quadratic was the best fitting mode. Small pills roundness was 15.04 °. 12 h floating rate was 75.07%. Percentages of in vitro cumulation release at 2,6 and 12 h of the option formulation pellets was 27.01%, 70.00% and 84.61%, respectively. The actual value was close to the predicted value. Deviation was less than 5%. CONCLUSION: Quadratic model was preferred in the optimization of formulation due to the statistical confidence. The multi-objective simultaneous optimization of Zuojin floating pellet formulation can be achieved by the central composite design-response surface methodology.

Hydrogen sulfide is a novel gasotransmitter with pivotal role in regulating lateral root formation in plants.

Hydrogen sulfide (H 2S), the third gasotransmitter after nitric oxide (NO) and carbon monoxide (CO), is a critical neuromodulator in the pathogenesis of various diseases from neurodegenerative diseases to diabetes or heart failure. The crosstalk between NO and H 2S has been well established in mammalian physiology. In planta, NO is demonstrated to regulate lateral root formation by acting downstream of auxin. The recent reports revealed that H 2S is a novel inducer of lateral root (LR) formation by stimulating the expression of cell cycle regulatory genes (CCRGs), acting similarly with NO, CO, and IAA. Interestingly, during the initiation of lateral root primordia, IAA is a potent inducer of endogenous H 2S and CO, which is produced by L-cysteine desulfhydrase (LCD) and heme oxygenase-1 (HO-1), respectively. The increasing evidences suggest that H 2S-promoted LR growth is dependent on the endogenous production of CO. In addition, our results indicate that the H 2S signaling in the regulation of LR formation can be associated to NO and Ca 2+. In this addendum, we advanced a proposed schematic model for H 2S-mediated signaling pathway of plant LR development.

In site bioimaging of hydrogen sulfide uncovers its pivotal role in regulating nitric oxide-induced lateral root formation.

Hydrogen sulfide (H2S) is an important gasotransmitter in mammals. Despite physiological changes induced by exogenous H2S donor NaHS to plants, whether and how H2S works as a true cellular signal in plants need to be examined. A self-developed specific fluorescent probe (WSP-1) was applied to track endogenous H2S in tomato (Solanum lycopersicum) roots in site. Bioimaging combined with pharmacological and biochemical approaches were used to investigate the cross-talk among H2S, nitric oxide (NO), and Ca(2+) in regulating lateral root formation. Endogenous H2S accumulation was clearly associated with primordium initiation and lateral root emergence. NO donor SNP stimulated the generation of endogenous H2S and the expression of the gene coding for the enzyme responsible for endogenous H2S synthesis. Scavenging H2S or inhibiting H2S synthesis partially blocked SNP-induced lateral root formation and the expression of lateral root-related genes. The stimulatory effect of SNP on Ca(2+) accumulation and CaM1 (calmodulin 1) expression could be abolished by inhibiting H2S synthesis. Ca(2+) chelator or Ca(2+) channel blocker attenuated NaHS-induced lateral root formation. Our study confirmed the role of H2S as a cellular signal in plants being a mediator between NO and Ca(2+) in regulating lateral root formation.

Microcystin-LR-induced phytotoxicity in rice crown root is associated with the cross-talk between auxin and nitric oxide.

Irrigation with cyanobacterial-blooming water containing microcystin-LR (MC-LR) poses threat to the growth of agricultural plants. Large amounts of rice (Oryza sativa) field in the middle part of China has been irrigating with cyanobacterial-blooming water. Nevertheless, the mechanism of MC-LR-induced phytotoxicity in the root of monocot rice remains unclear. In the present study, we demonstrate that MC-LR stress significantly inhibits the growth of rice root by impacting the morphogenesis rice crown root. MC-LR treatment results in the decrease in IAA (indole-3-acetic acid) concentration as well as the expression of CRL1 and WOX11 in rice roots. The application of NAA (1-naphthylacetic acid), an IAA homologue, is able to attenuate the inhibitory effect of MC-LR on rice root development. MC-LR treatment significantly inhibits OsNia1-dependent NO generation in rice roots. The application of NO donor SNP (sodium nitroprusside) is able to partially reverse the inhibitory effects of MC-LR on the growth of rice root and the expression of CRL1 and WOX11 by enhancing endogenous NO level in rice roots. The application of NO scavenger cPTIO [2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylinidazoline-1-oxyl-3-oxide] eliminates the effects of SNP. Treatment with NAA stimulates the generation of endogenous NO in MC-LR-treated rice roots. Treatment with NO scavenger cPTIO abolishes the ameliorated effect of NAA on MC-LR-induced growth inhibition of rice root. Treatment with SNP enhanced IAA concentration in MC-LR-treated rice roots. Altogether, our data suggest that NO acts both downstream and upstream of auxin in regulating rice root morphogenesis under MC-LR stress.

Antifungal activity of the osthol derivative JS-B against Phytophthora capsici.

JS-B (C(12)H(10)O(3)) is a derivative compound of osthol. The antifungal properties of JS-B were tested against 10 economically important plant pathogens. JS-B was effective in inhibiting the mycelial growth of Phytophthora capsici, and its inhibition on different stages of the life cycle of P. capsici was observed. The 50% effective concentration (EC(50)) of JS-B on mycelial dry weight and zoospore germination of P. capsici was 43.74 and 86.03 microg/ml, respectively. The rupture of released zoospores induced by JS-B was reduced by the addition of 100 mM glucose. The ultrastructural study showed that JS-B caused destruction of most of the mitochondrions, the concentration of cell nuclear, and the existing vesicles. When compared with dimethomorph, the activity of JS-B on P. capsici was determined under pot conditions. The result showed that JS-B has a curative effect on pepper blight.

Degradation of microcystin-LR and RR by a Stenotrophomonas sp. strain EMS isolated from Lake Taihu, China.

A bacterial strain EMS with the capability of degrading microcystins (MCs) was isolated from Lake Taihu, China. The bacterium was tentatively identified as a Stenotrophomonas sp. The bacterium could completely consume MC-LR and MC-RR within 24 hours at a concentration of 0.7 microg/mL and 1.7 microg/mL, respectively. The degradation of MC-LR and MC-RR by EMS occurred preferentially in an alkaline environment. In addition, mlrA gene involved in the degradation of MC-LR and MC-RR was detected in EMS. Due to the limited literature this gene has rare homologues. Sequencing analysis of the translated protein from mlrA suggested that MlrA might be a transmembrane protein, which suggests a possible new protease family having unique function.

Lysis of Microcystis aeruginosa with extracts from Chinese medicinal herbs.

Boiling water extracts of 66 selected Chinese medicinal herbs were screened for their anticyanobaterial activity against Microcystis aeruginosa by the soft-agar overlayer (SAO) method. Results indicated that extracts from 16 materials could inhibit the growth of this bacterial species. Among these anticyanobacterial samples, eight extracts showed low minimum inhibitory concentrations (MIC), including four extracts with MICs between 1 and 6 mg/mL, and four extracts with MICs < 1 mg/mL which could be considered useful to prevent the outbreak of cyanobacteria before the appearance of cyanobacterial blooms. Further study showed that three extracts with MIC values < 1 mg/mL induced intensive chlorophyll-a lysis within 7 days at the MIC. The results suggested that highly efficient anticyanobacterial compounds must be involved in the inhibitory activities. The final results indicated these three extracts (from Malaphis chinensis, Cynips gallae-tinctoriae and Fructus mume) had the potential to be developed as algicides due to their remarkably anticyanobacterial activities.

Isolation of a Methylobacillus sp. that degrades microcystin toxins associated with cyanobacteria.

Sludge from cyanobacteria-salvaged yard in Meiliang Bay, Lake Taihu in Wuxi, China was cultured and acclimated by inoculating microcystins (MCs) extract. Strain J10 was isolated by degrading the MC-RR and MC-LR and was identified as Methylobacillus sp. Further research showed that both MC-LR and MC-RR could be completely degraded at 17h after inoculation of J10, and the degradation probably was mediated by oxygen. Different enzymes, oxygen-dependent as well as oxygen-independent, with MC-degrading activity were found in the different fractions of J10 culture. However, the enzymes mainly responsible for MC degradation by J10 were oxygen-dependent and were probably bound to cell wall or outside the cytoplasmic membrane.

Efficacy of osthol, a potent coumarin compound, in controlling powdery mildew caused by Sphaerotheca fuliginea.

The efficacy of osthol, a natural coumarin compound, in controlling powdery mildew was evaluated in 2004-2005 in Anhui and Hebei Provinces of China. In both years, the treatments (osthol 15.0 and 18.0 g ai ha(- 1)) showed a stable control efficiency of 75.42, 81.24% and 76.36, 84.84%, respectively, at the Institutes of Plant Protection of Hebei Academy of Agricultural Sciences. In field experiments, osthol was as effective as difenoconazole in controlling powdery mildew and was more effective than triadimefon against Sphaerotheca fuliginea. Protection was expressed as a significant reduction (up to 87% compared with the control) in the mildewed leaf area in young pumpkin plants. Osthol strongly inhibited spore germination and mycelial growth of S. fuliginea in vitro, damaged the cell wall and the organelles of the pathogen. At 48 h after incubation, 50 microg ml(- 1) osthol could completely inhibit spore germination. These findings suggested that the effect of osthol on powdery mildew may be associated with the direct fungitoxic property against the pathogen. We conclude that osthol would be an attractive natural compound for practical agronomic use against powdery mildew.

Fengycin antibiotics isolated from B-FS01 culture inhibit the growth of Fusarium moniliforme Sheldon ATCC 38932.

Strain B-FS01, isolated from rape (Brassica napus) stem infected by Slerotinia sclerotiorum and identified as Bacillus subtilis, exhibited predominantly antagonistic activities against Fusarium moniliforme Sheldon ATCC 38932. Antifungal active compounds (AAC) were isolated and purified from the cultures of strain B-FS01 against ATCC 38932. The HPLC/electron spray ionization/collision-induced dissociation mass spectrum of AAC revealed a cluster of fengycin homologues containing fengycins A, fengycins B and a new type of fengycin. Further toxic assay of AAC in vitro against F. moniliforme indicated that AAC could strongly inhibit the growth of both mycelia and spores. In addition, treatment with AAC significantly modified the maize seed infection by ATCC 38932.