Characterization of Pythium nunn newly recorded in Japan and its antagonistic activity against P. ultimum var. ultimum

2010 ◽  
Vol 76 (4) ◽  
pp. 278-283 ◽  
Author(s):  
Sakura Kobayashi ◽  
Shihomi Uzuhashi ◽  
Motoaki Tojo ◽  
Makoto Kakishima
Keyword(s):  
Antagonistic Activity ◽  
Pythium Nunn

scholarly journals Nanopore-Sequencing Characterization of the Gut Microbiota of Melolontha melolontha Larvae: Contribution to Protection against Entomopathogenic Nematodes?

Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 396
Author(s):  
Ewa Sajnaga ◽  
Marcin Skowronek ◽  
Agnieszka Kalwasińska ◽  
Waldemar Kazimierczak ◽  
Karolina Ferenc ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Entomopathogenic Nematodes ◽  
Bacterial Species ◽  
Antagonistic Activity ◽  
Rrna Gene ◽  
Nanopore Sequencing ◽  
Bacterial Phyla ◽  
Melolontha Melolontha

This study focused on the potential relationships between midgut microbiota of the common cockchafer Melolontha melolontha larvae and their resistance to entomopathogenic nematodes (EPN) infection. We investigated the bacterial community associated with control and unsusceptible EPN-exposed insects through nanopore sequencing of the 16S rRNA gene. Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes were the most abundant bacterial phyla within the complex and variable midgut microbiota of the wild M. melolontha larvae. The core microbiota was found to include 82 genera, which accounted for 3.4% of the total number of identified genera. The EPN-resistant larvae differed significantly from the control ones in the abundance of many genera belonging to the Actinomycetales, Rhizobiales, and Clostridiales orders. Additionally, the analysis of the microbiome networks revealed different sets of keystone midgut bacterial genera between these two groups of insects, indicating differences in the mutual interactions between bacteria. Finally, we detected Xenorhabdus and Photorhabdus as gut residents and various bacterial species exhibiting antagonistic activity against these entomopathogens. This study paves the way to further research aimed at unravelling the role of the host gut microbiota on the output of EPN infection, which may contribute to enhancement of the efficiency of nematodes used in eco-friendly pest management.

scholarly journals ISOLATION, SCREENING, AND CHARACTERIZATION OF PROBIOTICS (LACTIC ACID BACTERIA) ANTAGONISTIC AGAINST Candida albicans

2017 ◽  
Vol 4 (2) ◽  
pp. 263
Author(s):  
Ida Ayu Ketut Ariningsih ◽  
Yan Ramona ◽  
Nyoman Semadi Antara
Keyword(s):  
Candida Albicans ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Reproductive Tract ◽  
Antagonistic Activity ◽  
Low Ph ◽  
Production Test ◽  
Ph Conditions ◽  
High Level

Candidacies in female reproductive tract are mainly caused by Candida albicans. This infection often causes serious problems, particularly on their reproductive tract (genital part). Until recently, control of this infection has relied on the use of antibiotics. However due to numerous bad side effects of antibiotics, lactic acid bacteria have been proposed as an alternative method to control the growth of Candida albicans. Therefore, this research was aimed to isolate, screen, and characterize lactic acid bacterial isolates (LAB) antagonistic against Candida albicans (the causative agent of candidacies infection in reproductive tract of human). LABs were isolated from various fermented foods, such as tape ketan and kimchi. Isolation of LABs was conducted by applying dilution and spread plate method on MRS agar medium supplemented with BCP indicator to distinguish LABs from non acid-producing bacteria. Colonies with indication to produce acid were screened for antagonistic activity against C. albicans on MRS agar and followed by characterization of those isolates (Gram stain, catalase production test, oxydase production, gas production test, resistance test to low pH conditions and to high level of NaDC (sodium deoxicolic), and test for ability to convert colic acid (CA) into deoxicolic acid (DCA)). The results showed that 46 LAB isolates were successfully isolated from samples of tape ketan and kimchi. Among those, 7 isolates showed antagonistic activity against C. albicans in in vitro tests. All these 7 candidates were also found to be resistance to low pH conditions (up to pH 2) and to high level of NaDC (up to 0.6 mM). Four most potential isolates were further testes for ability to convert colic acid into deoxycolic acid and none showed positive result, indicating that they all showed initial potential and safe for future human probiotic development (especially to be used to treat patients infected by C. albicans).

Physiological and molecular characterization of compost bacteria antagonistic to soil-borne plant pathogens

2017 ◽  
Vol 63 (5) ◽  
pp. 411-426 ◽  
Author(s):  
Rowida Mohamed ◽  
Emma Groulx ◽  
Stefanie Defilippi ◽  
Tamara Erak ◽  
James T. Tambong ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Antagonistic Activity ◽  
Antagonistic Bacteria ◽  
Antimicrobial Compounds ◽  
Fusarium Sambucinum ◽  
Inhibitory Compounds ◽  
Antimicrobial Lipopeptides ◽  
Chemical Pesticides ◽  
Insight Into

Disease suppressive composts have the potential to mitigate the risks associated with chemical pesticides. One of the main characteristics responsible for the suppressive nature of composts is their microbiological populations. To gain insight into the determinants responsible for their suppressive effects, we assayed composts to (i) isolate and identify beneficial antagonistic bacteria, (ii) quantify their antifungal and anti-oomycetal activities, (iii) extract inhibitory compounds produced by the bacteria, and (iv) identify antimicrobial lipopeptides produced by these bacteria. The antagonistic bacteria belonged to the genera Arthrobacter, Pseudomonas, Bacillus, Brevibacillus, Paenibacillus, and Rummeliibacillus and had the ability to antagonise the growth of Fusarium sambucinum, Verticillium dahliae, and (or) Pythium sulcatum. These bacteria produced antimicrobial compounds that affected the mycelial growth and (or) conidial germination of the pathogens. Mass spectrometry analyses showed the presence of various antimicrobial lipopeptides in Bacillus and Bacillus-related spp. extracts, demonstrating that they are responsible, at least in part, for the antagonistic activity of the bacteria. Results from this work provide greater insight into some of the biological, biochemical, and physiological determinants of suppressiveness in composts involved in the control of plant pathogens.

Characterization of AhR agonists reveals antagonistic activity in European herring gull (Larus argentatus) eggs

2015 ◽  
Vol 514 ◽  
pp. 211-218 ◽  
Author(s):  
Martine Muusse ◽  
Guttorm Christensen ◽  
Tânia Gomes ◽  
Anton Kočan ◽  
Katherine Langford ◽  
...  
Keyword(s):  
Antagonistic Activity ◽  
Larus Argentatus ◽  
Herring Gull

scholarly journals Recovery of Fusarium oxysporum Fo47 Mutants Affected in Their Biocontrol Activity After Transposition of the Fot1 Element

2002 ◽  
Vol 92 (9) ◽  
pp. 936-945 ◽  
Author(s):  
Sophie Trouvelot ◽  
Chantal Olivain ◽  
Ghislaine Recorbet ◽  
Quirico Migheli ◽  
Claude Alabouvette
Keyword(s):  
Fusarium Oxysporum ◽  
Insertional Mutagenesis ◽  
Wild Type Strain ◽  
Growth Habit ◽  
Antagonistic Activity ◽  
Phenotypic Characterization ◽  
Wild Type ◽  
Biocontrol Activity

To investigate the biocontrol mechanisms by which the antagonistic Fusarium oxysporum strain Fo47 is active against Fusarium wilt, a Fot1 transposon-mediated insertional mutagenesis approach was adopted to generate mutants affected in their antagonistic activity. Ninety strains in which an active Fot1 copy had transposed were identified with a phenotypic assay for excision and tested for their biocontrol activity against F. oxysporum f. sp. lini on flax in greenhouse experiments. Sixteen strains were affected in their capacity to protect flax plants, either positively (more antagonistic than Fo47) or negatively (less antagonistic). The molecular characterization of these mutants confirms the excision of Fot1 and its reinsertion in most of the cases. Moreover, we demonstrate that other transposable elements such as Fot2, impala, and Hop have no transposition activity in the mutant genomes. The phenotypic characterization of these mutants shows that they are affected neither in their in vitro growth habit nor in their competitiveness in soil compared with wild-type strain Fo47. These results show that mutants are not impaired in their saprophytic phase and suggest that the altered biocontrol phenotype should likely be expressed during the interaction with the host plant.

Isolation and characterization of lactobacilli from human faeces and indigenous fermented foods for their potential application as probiotics

2016 ◽  
Vol 62 (4) ◽  
pp. 349-359 ◽  
Author(s):  
Hemanti Mandal ◽  
Ruchi Jariwala ◽  
Tamishraha Bagchi
Keyword(s):  
Bile Salt ◽  
Lactobacillus Rhamnosus ◽  
Antagonistic Activity ◽  
Food Sources ◽  
Fermented Foods ◽  
E Coli ◽  
Isolation And Characterization ◽  
Acid And Bile Tolerance ◽  
Ht 29

This study was conducted to select Lactobacillus strains from various sources on the basis of their probiotic attributes, such as acid and bile tolerance, binding to intestinal cells, and antimicrobial activity. Twelve isolates were obtained from human and food sources and were evaluated against standard probiotic Lactobacillus rhamnosus GG (LGG). Isolates were also studied for their antibiotic susceptibility. Isolate Lactobacillus fermentum GPI-6 showed the best survival profile at 0.3% and 1% bile salt, as compared with LGG. Isolates Lactobacillus plantarum GRI-2 and Lactobacillus salivarius GPI-4 showed no reduction in survival rate at pH 2.5. As expected, isolates showed strain-specific differences when comparing various attributes. Isolates GPI-4, GPI-7, and FA-5 showed better adhesion to HT-29, while isolate GPI-4 adhered better to Caco-2 cells than did LGG. However, when studying their ability to compete with Escherichia coli O26:H11, isolates GPI-6 and GPI-7 significantly inhibited E. coli adhesion to both HT-29 and Caco-2 cells compared with LGG. In conclusion, isolates GPI-4, GPI-7, and FA-5 showed excellent binding ability and antagonistic activity and better tolerance to acidic pH (pH 2.5) and to different bile salt concentrations in comparison with LGG, and hence, they could be considered as potential probiotic candidates.

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