For about half a century, chemical control has played a major role in plant disease control. However, the long-term irrational use of chemical pesticide produces many problems. In nature, there exit extensive antagoni...For about half a century, chemical control has played a major role in plant disease control. However, the long-term irrational use of chemical pesticide produces many problems. In nature, there exit extensive antagonistic microorganisms which are tightly concerned with plant pathogenic microbes, and biological pesticides can be researched to control related pathogenic microbes from its metabolites. It's an important research direction of new pesticide development. The Bacillus is the ideal and frequently studied object of bio-control bacteria, and it can produce some entospores with following characteristics such as heat-resistant, drought tolerance, antiultraviolet and organic solvent. In this article, the bio-control mechanism, problems and application prospects of the Bacillus were reviewed to promote the application in new biological pesticide.展开更多
[Objective] This study aimed to explore the effects of spores and crude toxins of Helminthosporium gramineum Rabenh f. sp. echinochloae(HGE) on the ac- tivity of defensive enzymes of barnyardgrass [Echinochloa crus-...[Objective] This study aimed to explore the effects of spores and crude toxins of Helminthosporium gramineum Rabenh f. sp. echinochloae(HGE) on the ac- tivity of defensive enzymes of barnyardgrass [Echinochloa crus-galli (L.) Beauv.]. [Method] The effects of spores and crude toxins of HGE, as well as the mixture of spores and crude toxins on the activity of defensive enzymes in barnyardgrass were determined under laboratory conditions. [Result] Spores and crude toxins of HGE had varying degrees of effects on PAL and POD activity, and no obvious effect on SOD activity in barnyardgrass. In addition, spores and toxins had some similar im- pacts on the defensive enzymes in barnyardgrass. [Conclusion] Since toxins have similar effects on the hosts as spores of fungal pathogen do, they can be a substi- tute for the fungal pathogen in studying the partial pathogenic mechanism of this pathogen due to its complexity in pathogenic process.展开更多
[Objective] This study was conducted to screen high-efficient low-toxicity new compound preparation for control of Glomerella cingulata. [Method] The toxicity of pyraclostrobin, tebuconazole and their mixed preparatio...[Objective] This study was conducted to screen high-efficient low-toxicity new compound preparation for control of Glomerella cingulata. [Method] The toxicity of pyraclostrobin, tebuconazole and their mixed preparations to Glomerella cingulata was determined by mycelial growth rate method, and their control effects on Glomerella cingulata were evaluated by field efficacy test. [Result] The mixed preparations of pyraclostrobin and tebuconazole at mass ratios of 5:1, 3:1, 1:1, 1:3 and 1:5 exhibited ECso values to mycelial growth of Glomerella cingulata of 0.612 9, 0.530 1, 0.232 6, 0.232 8 and 0.329 6 iJg/ml, respectively; and the 5 preparations exhibit- ed synergistic coefficients (SRs) to Glomerella cingulata of 1.29, 1.33, 2.29, 1.84 and 1.22, respectively, and among them, the preparation with mass ratio of 1:1 showed the highest synergism. The field efficacy test showed that the field control effects of 1 000 times, 2 000 times and 3 000 times dilutions of 25% pyraclostrobin-tebuconazole suspension, 5 000 times dilution of 430 g/L tebuconazole suspension and 2 000 times dilution of 250 g/L pyraclostrobin EC were 91.54%, 90.80%, 82.88%, 76.43% and 74.10%, respectively. [Conclusions] Therefore, the mixed preparations of pyraclostrobin and tebuconazole showed remarkable synergism on control of Glomerella cingulata, and preparation with the mixing ratio of 1:1 exhibited the most significant synergism on Glomerella cingulata. For soaking treatment to fruit clusters with 1 000-2 000 times dilution of 25% pyraclostrobin .tebuconazole suspension, the field efficacy to Glomerella cingulata was over 90%.展开更多
[Objective] To screen out the biological compound bactericides for grape anthracnose, reduce and replace the use of chemical pesticide. [Methods] The de- termination on the indoor bacteriostatic activity of different ...[Objective] To screen out the biological compound bactericides for grape anthracnose, reduce and replace the use of chemical pesticide. [Methods] The de- termination on the indoor bacteriostatic activity of different proportions of Bacillus subtilis and pyraclostrobin to grape anthracnose was carried out, and mycelial growth rate method was adopted to determine the toxicity of Bacillus subtilis and pyraclostrobin as well as their 5 mixtures to grape anthracnose. [Results] The EC50 of Bacillus subtilis and pyraclostrobin as well as their mixture combinations of 1:1, 1:2, 1:3, 1:4 and 1:5 to grape anthracnose were respectively 1.969 8, 1.527 4, 1.373 2, 1.294 8 and 1.247 3 μg/ml; the synergistic coefficients (SR) of the 5 mix- ture combinations to grape anthracnose were 1.70, 1.25, 1.13, 1.12 and 1.12, re- spectively, in which the synergistic effect of 1:1 was the largest. The indoor biologi- cal activity of pyraclostrobin(EC50 was 1.054 0μg/ml) was higher than that of Bacil- lus subtilis(EC50 was 15.017 5 μg/ml). 50 d after the agentia(before the harvesting), the investigation results showed that 1 000-fold dilution, 1 500-fold dilution and 2 000- fold dilution as well as each single dosage of 20% pyraclostrobin .200×10^8 cfu/g Bacillus subtili wettable powder all had better control efficiency to grape anthracnose after fruit setting and before bagging, in which the treatments of high concentration and middle concentration were higher than the treatments of low concentration and two single dosages: the highest control efficiency of high concentration was 90.03%, which was higher than all other treatments; the control efficiency of middle concen- tration was 87.01%, which was higher than that of low concentration and each sin- gle dosage; the control efficiency of low concentration was 84.11%, which was high- er than 1 000-fold dilution of 1 000×10^8 cfu/g Bacillus subti/i wettable powder (the control efficiency was 64.60%) and 2 000-fold dilution of 250 g/L Bacillus subti/i wettable powder (the control efficiency was 81.07%). In addition, each treatment al- so had better control efficiency to other cluster diseases, such as white rot, etc., and the control efficiency was almost the same as that of anthracnose. [Conclusion] It was suggested that the prevention concentration of 20% pyraclostrobin .200×10^8 cfu/g Bacillus subtili wettable powder to grape anthracnose after fruit setting and before bagging was 1 000-fold - 2 000-fold dilution.展开更多
[Objective] This study was conducted to investigate the biocontrol activity of Streptomyces corchorusii strain NF0919 and Bacillus subtilis D J-6 WP to grape downy mildew. [Methed] We determined the indoor toxicity of...[Objective] This study was conducted to investigate the biocontrol activity of Streptomyces corchorusii strain NF0919 and Bacillus subtilis D J-6 WP to grape downy mildew. [Methed] We determined the indoor toxicity of the supernatant of S. corchorusii strain NF0919, 1.0×1011 cfu/g B. subtilis D J-6 WP, mancozeb and dimethomorph on Plasmopara viticola by the leaf disc method, respectively, and a field efficacy trial was conducted. [Result] The results showed that the ECso values of the supernatant of strain NF0919, 1.0×1011cfu/g B. subtilis D J-6 WP, mancozeb and dimethomorph were 96.285 9, 86.603 8, 69.947 2 and 7.263 6 μg/ml, respec- tively. The values of field efficacy in preventive experiments for grape downy mildew on the 7th day after 2 times of spraying 20 times diluent of the supernatant of strain NF0919 and 1 000 times diluent of 1.0×1011 cfu/g B. subtilis D J-6 WP were 71.55% and 70.71%, respectively, and the values of field efficacy on the 14th day after the 2 times of fungicide application were 67.54% and 68.19%, respectively. The values of field efficacy in curative experiments on the 7th day after 2 times of spraying 20 times diluent of the supematant of strain NF0919 and 1 000 times diluent of 1.0×1011 cfu/g B. subtilis D J-6 WP were 59.72% and 56.07%, respectively, and the val- ues of field efficacy on the 14th day after the 2 times of fungicide application were 56.88% and 57.46%, respectively. The field efficacy values of the 2 tested biocon- trol agents were equivalent. The protective effect showed no significant difference between each of tested biocontrol agents and 300 times diluent of 50% mancozeb WP, but there was a significant difference in the efficacy between each of tested biocontrol agents and 200 times diluent of 40% dimethomorph SC. [Conclusion] The S. corchorusii strain NF0919 and B. subtilis D J-6 WP had certain biocontrol poten- tial to grape downy mildew and development value.展开更多
[Objective] This study aims to screen for the high effective fungicides which could significantly decrease the disease incidence and disease index of rice false smut. [Method] The inhibitory activities of the fungicid...[Objective] This study aims to screen for the high effective fungicides which could significantly decrease the disease incidence and disease index of rice false smut. [Method] The inhibitory activities of the fungicide against mycelial growth of Ustilaginoidea virens were measured to in vitro evaluate the ECho values. And 17 fungicides were sprayed to evaluate the efficacy and effect of the fungicides tested in the field trials on the rice characters, [Result] The results showed that epoxicona- zole, difenoconazole, propiconazole and procloraz exhibited high inhibitory activity against mycelial growth of Ustilaginoidea virens with the ECso values 0.04, 0.07, 0.12 and 0.11 pg/ml, respectively. The results of field trials showed that the efficacy of Wen- quning, and fungicides such as difenoconazole, prochloraz, propiconazole, epoxi- conazole and their mixtures in controlling rice false smut were all 70% or more. [Conclusion] The 17 tested fungicides behaved efficacy in controlling rice false smut and did not cause drug injury on leaves and grains of rice plants, sprayed when flag leaves of rice fully expanded.展开更多
With the use of a seed washing technique, more than 4000 Gram negative bacteria were isolated by two improved isolation methods from 446 batches of 1 kg rice seed samples obtained from 22 provinces in the Philippines....With the use of a seed washing technique, more than 4000 Gram negative bacteria were isolated by two improved isolation methods from 446 batches of 1 kg rice seed samples obtained from 22 provinces in the Philippines. They were initially characterized on the basis of colony morphology and results of biochemical and pathogenicity tests. Six hundred and fifty two strains were further identified by Biolog, from which 133 were selected for fatty acid methyl ester (FAME) analysis together with 80 standard reference!strains. Sixteen species or types of Pseudomonas and 17 genera of non pseudomonads were identified, more than one third of which have not been recorded in rice. The most predominant species observed were P. putida and P. fulva. About 17% of the strains of Pseudomonas and 2% of the non pseudomonads were antagonistic to one or more fungal or bacterial pathogens of rice. Rice seed is an important source of biological control agents.展开更多
Clostridium septicum(C.septicum)gas gangrene is well documented in the literature,typically in the setting of trauma or immunosuppression.In this paper,we report a unique case of spontaneous clostridial myonecrosis in...Clostridium septicum(C.septicum)gas gangrene is well documented in the literature,typically in the setting of trauma or immunosuppression.In this paper,we report a unique case of spontaneous clostridial myonecrosis in a patient with Crohn's disease and sulfasalazineinduced neutropenia.The patient presented with left thigh pain,vomiting and diarrhea.Blood tests demonstrated a profound neutropenia,and magnetic resonance imaging of the thigh confirmed extensive myonecrosis.The patient underwent emergency hip disarticulation,followed by hemicolectomy.C.septicum was cultured from the blood.Following completion of antibiotic therapy,the patient developed myonecrosis of the right pectoral muscle necessitating further debridement,and remains on lifelong prophylactic antibiotic therapy.展开更多
According to a review article by Biecker et al published in a previous issue of World Journal of Gastroenterology in March 2011,intestinal decontamination with norfloxacin remains the mainstay of primary prophylaxis o...According to a review article by Biecker et al published in a previous issue of World Journal of Gastroenterology in March 2011,intestinal decontamination with norfloxacin remains the mainstay of primary prophylaxis of spontaneous bacterial peritonitis(SBP) at the expense of development of quinolone-resistant bacteria after long-term use.In our research,the administration of a 4-wk regimen with rifaximin 1200 mg/d reduced significantly the ascitic neutrophil count in cirrhotic patients with sterile ascites in line with a significant decrease in plasma endotoxin levels.Our observations concur with recent findings,showing a significantly reduced 5-year probability of SBP in cirrhotic patients taking rifaximin.展开更多
The water extract of dry mycelium ofPenicillium chrysogenum (DME) was used to induce resistance in Virginia tobacco plants against Phtophthora parasitica var. nicotianae. Results showed that the efficacy of DME in c...The water extract of dry mycelium ofPenicillium chrysogenum (DME) was used to induce resistance in Virginia tobacco plants against Phtophthora parasitica var. nicotianae. Results showed that the efficacy of DME in controlling black shank disease depended on both DME solution concentration and its' treatment methodology. Soil application of 1.5-5% DME 72 hr before inoculation with Phtophthora parasitica vat. nicotianae provided highly significant protection against black shank, relative to the control without DME treatment. Optimized tobacco plant treatment with 2.5% DME significantly increased peroxidase (POD) and polyphenol oxidase (PPO) activity levels in the upper leaf sections of the tobacco plants. DME had no direct antifungal activity on the growth of Phtophthora parasitica var. nicotianae in vitro, suggesting that disease control with DME treatment resulted from the induced propagation of natural defense mechanisms in the tobacco plants.展开更多
The molecular factors involved in the three-way interaction between plant, pathogenic fungi and antagonistic/biocontrol fungi, such as Trichoderma, are still poorly understood, even if they represent a matter of inter...The molecular factors involved in the three-way interaction between plant, pathogenic fungi and antagonistic/biocontrol fungi, such as Trichoderma, are still poorly understood, even if they represent a matter of interest for improving crop management and developing new strategies for plant diseases control. The aim of this work is to investigate the components involved in this interaction and, for this purpose, a proteomic approach was used. 2-D maps of the protein extracts from the single components in various interactions between plants (potato, bean, tobacco or tomato), pathogens (Botrytis cinerea, Rhizoctonia solani or Pythium ultimum) and biocontrol fungi (Trichoderma atroviride strain P1 or Trichoderma harzianum strain T22) were obtained. The proteome of each partner was collected separately and extracted by acetone precipitation in presence of trichloroacetic acid and a reducing agent (DTT). The extracted proteins were separated by isoelectrofocusing (IEF), using IPG (Immobilized pH gradient) strips, followed by SDS-PAGE. In order to improve resolution the separations were performed both on wide than narrow pH range and on different gel lengths. Differential spots were noted in the proteome of the three-way interaction when compared to each single component. These were further characterized by mass spectrometry and in silico analysis with the aim of identifying and cloning the relative genes. During the in vitro interaction of T. harzianum strain T22 with tomato and the culture filtrate or cell walls of pathogens, the spot number was higher than in the presence of pathogen biomass. In terms of Trichoderma differential proteins displayed on 2D gels, the most important changes were obtained in the presence of P. ultimum . During the in vivo interaction with tomato, the antagonist proteome changed much more in presence of soilborne fungi R. solani and P. ultimum than with the foliar fungus B. cinerea, both in terms of total and increased or novel spots. In silico analysis of some of those spots revealed homology with intracellular enzymes (GTPases, hydrolases) and with stress-related proteins (heat shock proteins HSP70, bacteriocin cloacin). Specific proteins in the plant proteome, i.e. pathogenesis-related proteins, have been identified during the in vivo interaction of bean with R. solani and T. atroviride strain P1. This is in agreement with the demonstrated ability of these beneficial fungi to induce plant systemic disease resistance by activating expression of defence-related genes. Proteins extracted from T. atrovride strain P1 which were analysed by mass spectrometry, revealed some interesting homologies with a fungal hydrophobin of Pleurotus ostreatus and an ABC transporter of Ralstonia metallidurans. These could represent molecular factors involved in the antagonistic mechanisms of Trichoderma and play a role in the three-way interaction with the plant and other microbes.展开更多
Bron et al presented a retrospective study regarding the prophylactic use of antibiotics for variceal hemorrhage. Antibiotics appeared to improve the survival rate of patients without increasing clostridium difficile ...Bron et al presented a retrospective study regarding the prophylactic use of antibiotics for variceal hemorrhage. Antibiotics appeared to improve the survival rate of patients without increasing clostridium difficile infection (CDI). We argue against the conclusion of the authors and consider that this result may be simply due to concurrent use of metronidazole, a therapeutic agent against CDI.展开更多
The gut flora plays an important role in the pathogenesis of the complications of cirrhosis. Hepatic encephalopathy (HE) represents a broad continuum of neuropsychological dysfunction in patients with acute or chronic...The gut flora plays an important role in the pathogenesis of the complications of cirrhosis. Hepatic encephalopathy (HE) represents a broad continuum of neuropsychological dysfunction in patients with acute or chronic liver disease and/or porto-systemic shunting of blood flow and it manifests with progressive deterioration of the superior neurological functions. The pathophysiology of this disease is complex, as it involves overproduction and reduced metabolism of various neurotoxins, particularly ammonia. Management of HE is diversified and requires several steps: elimination of precipitating factors, removal of toxins, proper nutritional support, modulation of resident fecal flora and downregulation of systemic and gut-derived inflammation. This review will provide an overview of gut barrier function and the influence of gut-derived factors on HE, focusing on the role of gut microbiota in the pathogenesis of HE and the recent literature findings on its therapeutic manipulation.展开更多
基金Supported by Accelerated Program of Sichuan Academy of Agricultural Sciences(2013QNJJ-019)Spark Program of Ministry of Science and Technology(2011GA-810011)Special Program of Modern Agricultural Technological System(No.CARS-22)~~
文摘For about half a century, chemical control has played a major role in plant disease control. However, the long-term irrational use of chemical pesticide produces many problems. In nature, there exit extensive antagonistic microorganisms which are tightly concerned with plant pathogenic microbes, and biological pesticides can be researched to control related pathogenic microbes from its metabolites. It's an important research direction of new pesticide development. The Bacillus is the ideal and frequently studied object of bio-control bacteria, and it can produce some entospores with following characteristics such as heat-resistant, drought tolerance, antiultraviolet and organic solvent. In this article, the bio-control mechanism, problems and application prospects of the Bacillus were reviewed to promote the application in new biological pesticide.
基金Supported by Research Fund of the State Tobacco Monopoly Bureau(110201002002)the Open Research Project of Key Laboratory of Tobacco Genetics and Breeding in the Tobacco Industry(TB201006)~~
文摘[Objective] This study aimed to explore the effects of spores and crude toxins of Helminthosporium gramineum Rabenh f. sp. echinochloae(HGE) on the ac- tivity of defensive enzymes of barnyardgrass [Echinochloa crus-galli (L.) Beauv.]. [Method] The effects of spores and crude toxins of HGE, as well as the mixture of spores and crude toxins on the activity of defensive enzymes in barnyardgrass were determined under laboratory conditions. [Result] Spores and crude toxins of HGE had varying degrees of effects on PAL and POD activity, and no obvious effect on SOD activity in barnyardgrass. In addition, spores and toxins had some similar im- pacts on the defensive enzymes in barnyardgrass. [Conclusion] Since toxins have similar effects on the hosts as spores of fungal pathogen do, they can be a substi- tute for the fungal pathogen in studying the partial pathogenic mechanism of this pathogen due to its complexity in pathogenic process.
基金Supported by Jiangsu Agricultural Science and Technology Independent Innovation Fund(CX(14)2056)Science & Technology Specific Project for Enriching People and Strengthening County Economy in China(BN20156222)~~
文摘[Objective] This study was conducted to screen high-efficient low-toxicity new compound preparation for control of Glomerella cingulata. [Method] The toxicity of pyraclostrobin, tebuconazole and their mixed preparations to Glomerella cingulata was determined by mycelial growth rate method, and their control effects on Glomerella cingulata were evaluated by field efficacy test. [Result] The mixed preparations of pyraclostrobin and tebuconazole at mass ratios of 5:1, 3:1, 1:1, 1:3 and 1:5 exhibited ECso values to mycelial growth of Glomerella cingulata of 0.612 9, 0.530 1, 0.232 6, 0.232 8 and 0.329 6 iJg/ml, respectively; and the 5 preparations exhibit- ed synergistic coefficients (SRs) to Glomerella cingulata of 1.29, 1.33, 2.29, 1.84 and 1.22, respectively, and among them, the preparation with mass ratio of 1:1 showed the highest synergism. The field efficacy test showed that the field control effects of 1 000 times, 2 000 times and 3 000 times dilutions of 25% pyraclostrobin-tebuconazole suspension, 5 000 times dilution of 430 g/L tebuconazole suspension and 2 000 times dilution of 250 g/L pyraclostrobin EC were 91.54%, 90.80%, 82.88%, 76.43% and 74.10%, respectively. [Conclusions] Therefore, the mixed preparations of pyraclostrobin and tebuconazole showed remarkable synergism on control of Glomerella cingulata, and preparation with the mixing ratio of 1:1 exhibited the most significant synergism on Glomerella cingulata. For soaking treatment to fruit clusters with 1 000-2 000 times dilution of 25% pyraclostrobin .tebuconazole suspension, the field efficacy to Glomerella cingulata was over 90%.
基金Supported by the Independent Innovation Fund Project of Agricultural Science and Technology in Jiangsu Province[CX(14)2056]Agricultural Science&Technology Supporting Program of Zhenjiang City(NY2014005)Science and Technology Innovation Items of Jurong City(NY2013026)~~
文摘[Objective] To screen out the biological compound bactericides for grape anthracnose, reduce and replace the use of chemical pesticide. [Methods] The de- termination on the indoor bacteriostatic activity of different proportions of Bacillus subtilis and pyraclostrobin to grape anthracnose was carried out, and mycelial growth rate method was adopted to determine the toxicity of Bacillus subtilis and pyraclostrobin as well as their 5 mixtures to grape anthracnose. [Results] The EC50 of Bacillus subtilis and pyraclostrobin as well as their mixture combinations of 1:1, 1:2, 1:3, 1:4 and 1:5 to grape anthracnose were respectively 1.969 8, 1.527 4, 1.373 2, 1.294 8 and 1.247 3 μg/ml; the synergistic coefficients (SR) of the 5 mix- ture combinations to grape anthracnose were 1.70, 1.25, 1.13, 1.12 and 1.12, re- spectively, in which the synergistic effect of 1:1 was the largest. The indoor biologi- cal activity of pyraclostrobin(EC50 was 1.054 0μg/ml) was higher than that of Bacil- lus subtilis(EC50 was 15.017 5 μg/ml). 50 d after the agentia(before the harvesting), the investigation results showed that 1 000-fold dilution, 1 500-fold dilution and 2 000- fold dilution as well as each single dosage of 20% pyraclostrobin .200×10^8 cfu/g Bacillus subtili wettable powder all had better control efficiency to grape anthracnose after fruit setting and before bagging, in which the treatments of high concentration and middle concentration were higher than the treatments of low concentration and two single dosages: the highest control efficiency of high concentration was 90.03%, which was higher than all other treatments; the control efficiency of middle concen- tration was 87.01%, which was higher than that of low concentration and each sin- gle dosage; the control efficiency of low concentration was 84.11%, which was high- er than 1 000-fold dilution of 1 000×10^8 cfu/g Bacillus subti/i wettable powder (the control efficiency was 64.60%) and 2 000-fold dilution of 250 g/L Bacillus subti/i wettable powder (the control efficiency was 81.07%). In addition, each treatment al- so had better control efficiency to other cluster diseases, such as white rot, etc., and the control efficiency was almost the same as that of anthracnose. [Conclusion] It was suggested that the prevention concentration of 20% pyraclostrobin .200×10^8 cfu/g Bacillus subtili wettable powder to grape anthracnose after fruit setting and before bagging was 1 000-fold - 2 000-fold dilution.
基金Supported by Science&Technology Specific Project for Enriching People and Strengthening County Economy in China(BN20156222)Jiangsu Agricultural Science and Technology Independent Innovation Fund(CX(14)2056)
文摘[Objective] This study was conducted to investigate the biocontrol activity of Streptomyces corchorusii strain NF0919 and Bacillus subtilis D J-6 WP to grape downy mildew. [Methed] We determined the indoor toxicity of the supernatant of S. corchorusii strain NF0919, 1.0×1011 cfu/g B. subtilis D J-6 WP, mancozeb and dimethomorph on Plasmopara viticola by the leaf disc method, respectively, and a field efficacy trial was conducted. [Result] The results showed that the ECso values of the supernatant of strain NF0919, 1.0×1011cfu/g B. subtilis D J-6 WP, mancozeb and dimethomorph were 96.285 9, 86.603 8, 69.947 2 and 7.263 6 μg/ml, respec- tively. The values of field efficacy in preventive experiments for grape downy mildew on the 7th day after 2 times of spraying 20 times diluent of the supernatant of strain NF0919 and 1 000 times diluent of 1.0×1011 cfu/g B. subtilis D J-6 WP were 71.55% and 70.71%, respectively, and the values of field efficacy on the 14th day after the 2 times of fungicide application were 67.54% and 68.19%, respectively. The values of field efficacy in curative experiments on the 7th day after 2 times of spraying 20 times diluent of the supematant of strain NF0919 and 1 000 times diluent of 1.0×1011 cfu/g B. subtilis D J-6 WP were 59.72% and 56.07%, respectively, and the val- ues of field efficacy on the 14th day after the 2 times of fungicide application were 56.88% and 57.46%, respectively. The field efficacy values of the 2 tested biocon- trol agents were equivalent. The protective effect showed no significant difference between each of tested biocontrol agents and 300 times diluent of 50% mancozeb WP, but there was a significant difference in the efficacy between each of tested biocontrol agents and 200 times diluent of 40% dimethomorph SC. [Conclusion] The S. corchorusii strain NF0919 and B. subtilis D J-6 WP had certain biocontrol poten- tial to grape downy mildew and development value.
基金Supported by Agricultural S&T Innovation:Genetic Structure Analysis and Parasitism Fitness of U.virens in Anhui Province(14B1148)Special Fund for Talent Development:Pesticide Innovation and High-efficient Application Technology(13C1109)~~
文摘[Objective] This study aims to screen for the high effective fungicides which could significantly decrease the disease incidence and disease index of rice false smut. [Method] The inhibitory activities of the fungicide against mycelial growth of Ustilaginoidea virens were measured to in vitro evaluate the ECho values. And 17 fungicides were sprayed to evaluate the efficacy and effect of the fungicides tested in the field trials on the rice characters, [Result] The results showed that epoxicona- zole, difenoconazole, propiconazole and procloraz exhibited high inhibitory activity against mycelial growth of Ustilaginoidea virens with the ECso values 0.04, 0.07, 0.12 and 0.11 pg/ml, respectively. The results of field trials showed that the efficacy of Wen- quning, and fungicides such as difenoconazole, prochloraz, propiconazole, epoxi- conazole and their mixtures in controlling rice false smut were all 70% or more. [Conclusion] The 17 tested fungicides behaved efficacy in controlling rice false smut and did not cause drug injury on leaves and grains of rice plants, sprayed when flag leaves of rice fully expanded.
文摘With the use of a seed washing technique, more than 4000 Gram negative bacteria were isolated by two improved isolation methods from 446 batches of 1 kg rice seed samples obtained from 22 provinces in the Philippines. They were initially characterized on the basis of colony morphology and results of biochemical and pathogenicity tests. Six hundred and fifty two strains were further identified by Biolog, from which 133 were selected for fatty acid methyl ester (FAME) analysis together with 80 standard reference!strains. Sixteen species or types of Pseudomonas and 17 genera of non pseudomonads were identified, more than one third of which have not been recorded in rice. The most predominant species observed were P. putida and P. fulva. About 17% of the strains of Pseudomonas and 2% of the non pseudomonads were antagonistic to one or more fungal or bacterial pathogens of rice. Rice seed is an important source of biological control agents.
文摘Clostridium septicum(C.septicum)gas gangrene is well documented in the literature,typically in the setting of trauma or immunosuppression.In this paper,we report a unique case of spontaneous clostridial myonecrosis in a patient with Crohn's disease and sulfasalazineinduced neutropenia.The patient presented with left thigh pain,vomiting and diarrhea.Blood tests demonstrated a profound neutropenia,and magnetic resonance imaging of the thigh confirmed extensive myonecrosis.The patient underwent emergency hip disarticulation,followed by hemicolectomy.C.septicum was cultured from the blood.Following completion of antibiotic therapy,the patient developed myonecrosis of the right pectoral muscle necessitating further debridement,and remains on lifelong prophylactic antibiotic therapy.
文摘According to a review article by Biecker et al published in a previous issue of World Journal of Gastroenterology in March 2011,intestinal decontamination with norfloxacin remains the mainstay of primary prophylaxis of spontaneous bacterial peritonitis(SBP) at the expense of development of quinolone-resistant bacteria after long-term use.In our research,the administration of a 4-wk regimen with rifaximin 1200 mg/d reduced significantly the ascitic neutrophil count in cirrhotic patients with sterile ascites in line with a significant decrease in plasma endotoxin levels.Our observations concur with recent findings,showing a significantly reduced 5-year probability of SBP in cirrhotic patients taking rifaximin.
文摘The water extract of dry mycelium ofPenicillium chrysogenum (DME) was used to induce resistance in Virginia tobacco plants against Phtophthora parasitica var. nicotianae. Results showed that the efficacy of DME in controlling black shank disease depended on both DME solution concentration and its' treatment methodology. Soil application of 1.5-5% DME 72 hr before inoculation with Phtophthora parasitica vat. nicotianae provided highly significant protection against black shank, relative to the control without DME treatment. Optimized tobacco plant treatment with 2.5% DME significantly increased peroxidase (POD) and polyphenol oxidase (PPO) activity levels in the upper leaf sections of the tobacco plants. DME had no direct antifungal activity on the growth of Phtophthora parasitica var. nicotianae in vitro, suggesting that disease control with DME treatment resulted from the induced propagation of natural defense mechanisms in the tobacco plants.
文摘The molecular factors involved in the three-way interaction between plant, pathogenic fungi and antagonistic/biocontrol fungi, such as Trichoderma, are still poorly understood, even if they represent a matter of interest for improving crop management and developing new strategies for plant diseases control. The aim of this work is to investigate the components involved in this interaction and, for this purpose, a proteomic approach was used. 2-D maps of the protein extracts from the single components in various interactions between plants (potato, bean, tobacco or tomato), pathogens (Botrytis cinerea, Rhizoctonia solani or Pythium ultimum) and biocontrol fungi (Trichoderma atroviride strain P1 or Trichoderma harzianum strain T22) were obtained. The proteome of each partner was collected separately and extracted by acetone precipitation in presence of trichloroacetic acid and a reducing agent (DTT). The extracted proteins were separated by isoelectrofocusing (IEF), using IPG (Immobilized pH gradient) strips, followed by SDS-PAGE. In order to improve resolution the separations were performed both on wide than narrow pH range and on different gel lengths. Differential spots were noted in the proteome of the three-way interaction when compared to each single component. These were further characterized by mass spectrometry and in silico analysis with the aim of identifying and cloning the relative genes. During the in vitro interaction of T. harzianum strain T22 with tomato and the culture filtrate or cell walls of pathogens, the spot number was higher than in the presence of pathogen biomass. In terms of Trichoderma differential proteins displayed on 2D gels, the most important changes were obtained in the presence of P. ultimum . During the in vivo interaction with tomato, the antagonist proteome changed much more in presence of soilborne fungi R. solani and P. ultimum than with the foliar fungus B. cinerea, both in terms of total and increased or novel spots. In silico analysis of some of those spots revealed homology with intracellular enzymes (GTPases, hydrolases) and with stress-related proteins (heat shock proteins HSP70, bacteriocin cloacin). Specific proteins in the plant proteome, i.e. pathogenesis-related proteins, have been identified during the in vivo interaction of bean with R. solani and T. atroviride strain P1. This is in agreement with the demonstrated ability of these beneficial fungi to induce plant systemic disease resistance by activating expression of defence-related genes. Proteins extracted from T. atrovride strain P1 which were analysed by mass spectrometry, revealed some interesting homologies with a fungal hydrophobin of Pleurotus ostreatus and an ABC transporter of Ralstonia metallidurans. These could represent molecular factors involved in the antagonistic mechanisms of Trichoderma and play a role in the three-way interaction with the plant and other microbes.
文摘Bron et al presented a retrospective study regarding the prophylactic use of antibiotics for variceal hemorrhage. Antibiotics appeared to improve the survival rate of patients without increasing clostridium difficile infection (CDI). We argue against the conclusion of the authors and consider that this result may be simply due to concurrent use of metronidazole, a therapeutic agent against CDI.
文摘The gut flora plays an important role in the pathogenesis of the complications of cirrhosis. Hepatic encephalopathy (HE) represents a broad continuum of neuropsychological dysfunction in patients with acute or chronic liver disease and/or porto-systemic shunting of blood flow and it manifests with progressive deterioration of the superior neurological functions. The pathophysiology of this disease is complex, as it involves overproduction and reduced metabolism of various neurotoxins, particularly ammonia. Management of HE is diversified and requires several steps: elimination of precipitating factors, removal of toxins, proper nutritional support, modulation of resident fecal flora and downregulation of systemic and gut-derived inflammation. This review will provide an overview of gut barrier function and the influence of gut-derived factors on HE, focusing on the role of gut microbiota in the pathogenesis of HE and the recent literature findings on its therapeutic manipulation.