scholarly journals The Predatory Myxobacterium Citreicoccus inhibens gen. nov. sp. nov. Showed Antifungal Activity and Bacteriolytic Property against Phytopathogens

2021 ◽  
Vol 9 (10) ◽  
pp. 2137
Author(s):  
Yang Zhou ◽  
Shuoxing Yi ◽  
Yi Zang ◽  
Qing Yao ◽  
Honghui Zhu
Keyword(s):  
Antifungal Activity ◽  
Pathogenic Bacteria ◽  
Phytopathogenic Fungi ◽  
Antagonistic Activity ◽  
Extracellular Proteins ◽  
Morphological Observation ◽  
Rrna Gene ◽  
Fruiting Body Formation ◽  
Predatory Bacteria ◽  
Beneficial Traits

The application and promotion of biological control agents are limited because of poor efficacy and unstable performance in the field. Screening microorganisms with high antagonistic activity, effective adaptability, and high field-survival should be prospected. Myxobacteria are soil predatory bacteria with wide adaptability, which are considered as good antagonists. Here, we report a myxobacterium strain M34 isolated from subtropical forest soil in South China using the Escherichia coli baiting method. Based on the morphological observation, physiological test, biochemical characteristics, 16S rRNA gene sequence, and genomic data, strain M34 was identified as a novel genus and novel species, representing a new clade of Myxococcaceae, for which the name Citreicoccus inhibens gen. nov. sp. nov. is proposed (type strain M34T = GDMCC 1.2275T = KCTC 82453T). The typical features of M34, including fruiting body formation and extracellular fibrillar interconnection, indicated by microscopic observations, contributed to cell adaption in different environments. Furthermore, the strain showed antifungal activity against phytopathogenic fungi and predatory activity to both Gram-negative and Gram-positive phytopathogenic bacteria. The bioprotective mechanisms are attributed to the presence of pyrrolnitrin and derivative with antifungal activity and the extracellular proteins with lytic activity against pathogenic bacteria. Due to its multiple beneficial traits, strain M34 has the potential to be developed into a versatile biocontrol agent for the management of both fungal and bacterial phytopathogens.

scholarly journals Antifungal activity of several isolates of Trichoderma against Cladosporium and Botrytis

2018 ◽  
Vol 8 (1) ◽  
pp. 88-91 ◽  
Author(s):  
M. Skaptsov ◽  
S. Smirnov ◽  
M. Kutsev ◽  
O. Uvarova ◽  
T. Sinitsyna ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Trichoderma Harzianum ◽  
Its Region ◽  
Botanical Garden ◽  
Antagonistic Activity ◽  
Antagonistic Effect ◽  
Soil Samples ◽  
Morphological Observation ◽  
The South

<p><em>Trichoderma</em> isolates (SSBGT07, SSBGT08, SSBGT09, SSBGT10) were isolated from the soil samples of the South-Siberian Botanical Garden and identified using morphological observation and ITS region analysis as <em>Trichoderma harzianum</em>, <em>T. asperellum, T. ghanense</em>, and <em>T. longibranchiatum</em>. Antagonistic activity against <em>Cladosporium </em>sp. and<em> Botrytis </em>sp. was evaluated <em>in vitro</em>. All isolates showed antagonistic effect by competition against <em>Cladosporium </em>sp. <em>T. asperellum </em>and <em>T. longibranchiatum</em> showed antagonism against <em>Botrytis </em>sp. All isolates showed hyper sporulation on the sclerotia of <em>Botrytis</em> sp. (except the <em>T. ghanense</em>) and colonies of the <em>Cladosporium</em> sp. Our study provides new isolates that affect the <em>Cladosporium </em>sp. and<em> Botrytis </em>sp.</p>

scholarly journals Some endemic medicinal plants of Andamans with antimicrobial potential

2016 ◽  
Vol 1 (1) ◽  
pp. 10
Author(s):  
Asma Bibi ◽  
A. Thangamani ◽  
V. Venkatesalu
Keyword(s):  
Antibacterial Activity ◽  
Antifungal Activity ◽  
Pathogenic Bacteria ◽  
Phytopathogenic Fungi ◽  
Gram Negative Bacteria ◽  
Andaman Islands ◽  
Bacterial Strains ◽  
Endemic Plant ◽  
Ethanol Extracts ◽  
Endemic Plant Species

The present study was aimed to determine the antimicrobial activity of some endemic plant species used in folkloric medicine by the inhabitants of Andaman Islands, India. The ethanol extracts prepared from the leaves of four plants viz; Alstonia kurzii, Tabernaemontana crispa, Mangifera andamanica and Vitex diversifolia were assessed for antibacterial activity against clinically isolated human pathogenic bacteria and antifungal activity against some phytopathogenic fungi. The ethanol extracts showed more inhibition towards Gram positive than Gram negative bacteria and the bacterial strains showed more susceptibility than the fungal strains tested. Among the plants, Vitex diversifolia exhibited the highest antibacterial activity and Mangifera andamanica showed the highest antifungal activity.

scholarly journals Antagonistic Potential of Soil Streptomyces Isolates from Southern Thailand to Inhibit Foodborne Bacterial Pathogens

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Waenurama Chemoh ◽  
Wahida Bin-Ismail ◽  
Sawitree Dueramae
Keyword(s):  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Bacterial Pathogens ◽  
Antagonistic Activity ◽  
Rrna Gene ◽  
Rice Soils ◽  
Streptomyces Species ◽  
Genus Streptomyces ◽  
Crude Extracts ◽  
Broth Microdilution Method

Streptomyces are well known for their competence to produce thousands of bioactive secondary metabolites and enzymes. This study aimed to assess the inhibitory activities of crude extracts from diverse Streptomyces collected from rice soils in Narathiwat, Thailand, against foodborne bacterial pathogens. In total, 136 Actinomycete isolates were screened using a cross-streak method for the ability to produce effective metabolites against 5 pathogenic bacteria. Out of these, 19 (13.97%) isolates had antibacterial activity against at least one tested bacterium. Most of the isolates could strongly suppress the growth of S. aureus ATCC25923 and B. cereus MTCC430 except P. aeruginosa ATCC27853. On the basis of morphological, cultural, and biochemical characteristics, all potent isolates exhibited typical features that fitted the genus Streptomyces. Two of the 7 selected ethyl acetate crude extracts had good antagonistic activity against S. aureus ATCC25923 and B. cereus MTCC430 when tested using the agar well diffusion assay. Furthermore, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of the 2 extracts evaluated using the colorimetric broth microdilution method ranged from 256 to >1,024 μg/ml against the tested bacteria. The partial nucleotide sequences of the 16S rRNA gene led to identifying both active isolates as Streptomyces species. These active Streptomyces isolates could provide an interesting source for generating innumerable natural compounds with antibacterial activity that can presumably be developed to fight bacterial pathogens in the near future.

scholarly journals Identification of a Putative Mexican Strain of Serratia entomophila Pathogenic against Root-Damaging Larvae of Scarabaeidae (Coleoptera)

2007 ◽  
Vol 74 (3) ◽  
pp. 802-810 ◽  
Author(s):  
M. Eugenia Nuñez-Valdez ◽  
Marco A. Calderón ◽  
Eduardo Aranda ◽  
Luciano Hernández ◽  
Rosa M. Ramírez-Gama ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Phylogenetic Analyses ◽  
Significant Loss ◽  
Management Program ◽  
Extracellular Proteins ◽  
Proteinase K ◽  
Rrna Gene ◽  
White Grubs ◽  
Disease Symptoms ◽  
Lepidopteran Insect

ABSTRACT The larvae of scarab beetles, known as “white grubs” and belonging to the genera Phyllophaga and Anomala (Coleoptera: Scarabaeidae), are regarded as soil-dwelling pests in Mexico. During a survey conducted to find pathogenic bacteria with the potential to control scarab larvae, a native Serratia sp. (strain Mor4.1) was isolated from a dead third-instar Phyllophaga blanchardi larva collected from a cornfield in Tres Marías, Morelos, Mexico. Oral bioassays using healthy P. blanchardi larvae fed with the Mor4.1 isolate showed that this strain was able to cause an antifeeding effect and a significant loss of weight. Mortality was observed for P. blanchardi, P. trichodes, and P. obsoleta in a multidose experiment. The Mor4.1 isolate also caused 100% mortality 24 h after intracoelomic inoculation of the larvae of P. blanchardi, P. ravida, Anomala donovani and the lepidopteran insect Manduca sexta. Oral and injection bioassays were performed with concentrated culture broths of the Mor4.1 isolate to search for disease symptoms and mortality caused by extracellular proteins. The results have shown that Mor4.1 broths produce significant antifeeding effects and mortality. Mor4.1 broths treated with proteinase K lost the ability to cause disease symptoms and mortality, in both the oral and the injection bioassays, suggesting the involvement of toxic proteins in the disease. The Mor4.1 isolate was identified as a putative Serratia entomophila Mor4.1 strain based on numerical taxonomy and phylogenetic analyses done with the 16S rRNA gene sequence. The potential of S. entomophila Mor4.1 and its toxins to be used in an integrated pest management program is discussed.

scholarly journals Chromatographic profiles of antifungal exo- and endometabolites of Bacillus velezensis

2021 ◽  
Vol 2(26) ◽  
pp. 191-199
Author(s):  
T.M. Sidorova ◽  
◽  
A.M. Asaturova ◽  
V.V. Allakhverdyan ◽  
◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Fusarium Oxysporum ◽  
Phytopathogenic Fungi ◽  
Antagonistic Activity ◽  
Active Metabolites ◽  
Fungicidal Action ◽  
Antifungal Metabolites ◽  
Alternaria Sp ◽  
Tlc Analysis

The antifungal activity of the Bacillus bacteria is based on their ability to produce metabolites. Therefore, when selecting a strain that produces an effective biofungicide, it is necessary to assess the metabolism of bacteria. The aim of this work is to isolate exo- and endometabolites of the promising B. velezensis BZR 336g and B. velezensis BZR 517 strains and assess their antifungal activity. Studies were carried out in 2020–2021. The object of the study is a liquid culture of the B. velezensis BZR 336g and B. velezensis BZR 517 strains. Methods of liquid extraction, ascending thin layer chromatography (TLC), bioautography with a test-culture of Fusarium oxysporum var. orthoceras and Alternaria sp. fungi were used to analyze metabolites. The ability of the strains to accumulate a complex of active metabolites showing antifungal effect from fungistatic to fungicidal action was revealed. On the bioautogram of exometabolites, we found two most pronounced zones (Rf 0.18 and 0.29) of Fusarium oxysporum var. orthoceras BZR P1 growth inhibition (fungicide). Zones with Rf 0.58 for B. velezensis BZR 336g and Rf 0.70 for B. velezensis BZR 517 correspond to the test fungus growth retardation (fungistatic). Significant suppression of Alternaria sp. BZR P8 growth was also observed in two zones (Rf 0.18 and 0.29). The use of surfactin, iturin A, fengycin (Sigma-Aldrich®) in the TLC analysis made it possible to detect similar lipopeptides in the composition of metabolite complexes produced by the studied bacteria. It should be noted that the studied strains differed both in their ability to produce metabolites of different structure (can be found when analyzing chromatograms under ultraviolet light) and in their effect on phytopathogenic fungi in vitro. This may indicate possible differences in the mechanism of antagonistic activity of bacteria against phytopathogenic fungi. Thus, B. velezensis BZR 336g and B. velezensis BZR 517 produce a significant set of antifungal metabolites and can be used as strains to produce effective biofungicides.

Antagonistic Effect of Lactic Acid Bacteria and their Consortium with Yeast on Pathogenic Microorganisms

2021 ◽  
Vol 37 (5) ◽  
pp. 96-107
Author(s):  
Е.F. Semenova ◽  
G.P. Zaitsev ◽  
Е.А. Slastya ◽  
А.V. Omelchenko ◽  
I.A. Bugara ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Pathogenic Bacteria ◽  
Capric Acid ◽  
Dimethyl Fumarate ◽  
Culture Liquid ◽  
Phytopathogenic Fungi ◽  
Antagonistic Activity ◽  
Antagonistic Effect ◽  
Fungistatic Activity

Abstract-A comparative study of the influence of lactic acid bacteria and their consortium with yeast on the growth of pathogenic bacteria and fungi has been carried out. It was revealed that the proposed composition of probiotic microbial species has fungistatic activity and strongly pronounced fungicidal activity against mold micromycetes and phytopathogenic fungi, respectively. The consortium effectiveness in suppressing both bacteria and filamentous fungi exceeds that of the corresponding monocultures. Analysis of wheat seeds for the presence of fungi by germination in a humid chamber and on nutrient media showed that the association of a 3-day culture of lactic acid bacteria and yeast at a dilution of 1:100 significantly reduced the infection of plant material. The ability to suppress opportunistic and phytopathogenic microorganisms is explained by the presence in the microbial consortium culture liquid of metabolites with bactericidal and fungicidal properties: squalene, dimethyl fumarate, capric acid, lactic acid, acetic acid, caprylic acid, fumaric acid, butyric acid, decanol, butanol, pentanol and β-phenylethanol. Key words: lactic acid bacteria, consortium of microorganisms, antagonistic activity, phytopathogens, bacteria pathogenic for humans

scholarly journals Actinomycetes of Juniperus excelsa Bield. rhizosphere – antagonists of phytopathogenic microbiota

2018 ◽  
Vol 23 ◽  
pp. 340-345
Author(s):  
S. I. Tistechok ◽  
V. Ya. Syrvatka ◽  
V. O. Fedorenko ◽  
O. M. Gromyko
Keyword(s):  
Pathogenic Bacteria ◽  
Culture Method ◽  
Phytopathogenic Fungi ◽  
Antagonistic Activity ◽  
Dual Culture ◽  
Productivity Losses ◽  
Microbiological Methods ◽  
Juniperus Excelsa ◽  
Bacteria And Fungi ◽  
Phytopathogenic Microorganisms

Aim. Phytopathogenic microorganisms are one of the main causes of agricultural productivity losses. Thereby, the goal of this study was to evaluate actinomycetes strains, isolated from Juniperus excelsa Bield. rhizosphere, antagonistic activity against plant pathogenic bacteria and fungi. Methods. In this study we used microbiological methods for isolation actinomycetes from rhizosphere. Antagonistic activity was evaluated by using the dual culture method. Results. 372 actinomycete stains were isolated from J. excelsa Bield. rhizosphere. More than 60 % actinomyces isolates showed antibacterial activity against to lest one of the tested phytopathogenic bacteria genus Pseudomonas, Pectobacterium, Agrobacterium, Erwinia, Xanthomonas and 20.5 % of the tested phytopathogenic fungi genus Aspergillus, Alternaria, Fusarium, Botrytis. Only 2 strains had antagonistic activity to the all of the tested microorganisms and 62 strains, which had antagonistic activity to the one test-microorganism. Conclusions. Actinomicetes of J. excelsa Bield. rhizosphere are source for bioactive compounds against phytopatogenic microorganisms and showed good biotechnology potential. These results are the first step to the screening new biopesticides for controlling phytopatogenic diseases in plan. Keywords: actynomicetes, phytopathogens, biocontrol.

scholarly journals Seasonal Incidence of Autochthonous Antagonistic Roseobacter spp. and Vibrionaceae Strains in a Turbot Larva (Scophthalmus maximus) Rearing System

2004 ◽  
Vol 70 (12) ◽  
pp. 7288-7294 ◽  
Author(s):  
Mette Hjelm ◽  
Ana Riaza ◽  
Fernanda Formoso ◽  
Jette Melchiorsen ◽  
Lone Gram
Keyword(s):  
Pathogenic Bacteria ◽  
Vibrio Anguillarum ◽  
Scophthalmus Maximus ◽  
Antagonistic Activity ◽  
Early Summer ◽  
Rrna Gene ◽  
Fish Farms ◽  
Biochemical Tests ◽  
Seasonal Incidence ◽  
Regular Source

ABSTRACT Bacteria inhibitory to fish larval pathogenic bacteria were isolated from two turbot larva rearing farms over a 1-year period. Samples were taken from the rearing site, e.g., tank walls, water, and feed for larvae, and bacteria with antagonistic activity against Vibrio anguillarum were isolated using a replica plating assay. Approximately 19,000 colonies were replica plated from marine agar plates, and 341 strains were isolated from colonies causing clearing zones in a layer of V. anguillarum. When tested in a well diffusion agar assay, 173 strains retained the antibacterial activity against V. anguillarum and Vibrio splendidus. Biochemical tests identified 132 strains as Roseobacter spp. and 31 as Vibrionaceae strains. Partial sequencing of the 16S rRNA gene of three strains confirmed the identification as Roseobacter gallaeciensis. Roseobacter spp. were especially isolated in the spring and early summer months. Subtyping of the 132 Roseobacter spp. strains by randomly amplified polymorphic DNA with two primers revealed that the strains formed a very homogeneous group. Hence, it appears that the same subtype was present at both fish farms and persisted during the 1-year survey. This indicates either a common, regular source of the subtype or the possibility that a particular subtype has established itself in some areas of the fish farm. Thirty-one antagonists were identified as Vibrio spp., and 18 of these were V. anguillarum but not serotype O1 or O2. Roseobacter spp. strains were, in particular, isolated from the larval tank walls, and it may be possible to establish an antagonistic, beneficial microflora in the rearing environment of turbot larvae and thereby limit survival of pathogenic bacteria.

scholarly journals Evaluation of the antifungal activity of marine actinomycetes isolates against the phytopathogenic fungi Colletotrichum siamense KA: A preliminary study for new antifungal compound discovery

Pharmacia ◽  
2021 ◽  
Vol 68 (4) ◽  
pp. 837-843
Author(s):  
Qonita Gina Fadhilah ◽  
Iman Santoso ◽  
Andi Eko Maryanto ◽  
Sarini Abdullah ◽  
Yasman Yasman
Keyword(s):  
Antifungal Activity ◽  
Mangrove Ecosystem ◽  
Phytopathogenic Fungi ◽  
Antagonistic Activity ◽  
Antifungal Compound ◽  
Antifungal Compounds ◽  
Marine Actinomycetes ◽  
Colletotrichum Siamense ◽  
Preliminary Study ◽  
Different Strains

Marine actinomycetes are being explored to discover potential actinomycetes that produce antifungal compounds. In a previous study, marine actinomycetes isolates from the mangrove ecosystem were found to inhibit growth of the phytopathogenic fungi Colletotrichum siamense KA. In this study, the three of these isolates with the highest antagonistic activity—SM11, SM14, and SM15—were evaluated for their antifungal activity using antibiosis assay. The fermentation was performed in SCB:PDB medium (1:1) for 6, 9, and 12 days. The results showed that SM14 was the strongest potential isolate; it inhibited the growth of C. siamense KA on average up to 64.90% for 12 days on PDA filtrate medium. Molecular identification showed SM14 was closely related to Streptomyces sanyensis, but had differences in morphological and biochemical characteristics compared to SM11 or SM15. This indicated that the three isolates were different strains and may challenge further research on identifying and analyzing their antifungal compounds.

scholarly journals Microencapsulation of Citral and its Antifungal Activity into Pectin Films

2021 ◽  
Vol 12 (6) ◽  
pp. 7488-7502
Keyword(s):  
Antifungal Activity ◽  
Large Scale ◽  
Thermal Protection ◽  
Thermal Analyses ◽  
Phytopathogenic Fungi ◽  
Antagonistic Activity ◽  
Drying Process ◽  
Practical Applications ◽  
Postharvest Management

Citral is an essential oil with great antimicrobial activity, but its use in the food industry is limited due to its easy decomposition in room conditions. Therefore, this study aimed to microencapsulate citral by the spray drying process and incorporate the powder into pectin films to assess their antifungal activity. For this, solutions of maltodextrin (MD), Arabic gum (AG) sodium alginate (SA) at different concentrations were used to emulsify citral. The emulsion with 10:10:0.1 MD:AG:SA was selected to spray the drying process due to its small droplet size, monomodal size distribution, and low D[3,2], D[4,3], and span index. The dried powder had high solubility (83.4%), and low wettability time (27 s), moisture content (4.05%), and bulk density (0.72 g/cm3), allowing to infer powder stability and showing appropriate handling qualities on a large scale. Thermal analyses reveal that microparticles and pectin films provide thermal protection to citral from 37 to 175 °C. Concerning the antagonistic activity, pectin films added with citral microencapsulated had antifungal activity ranging from 42-68% against Penicillium italicum, Colletotrichum gloeosporioides, and Aspergillus niger under in vitro conditions. Therefore, these films serve as a basis for developing new edible coatings with practical applications in the postharvest management of phytopathogenic fungi.

Sign in / Sign up

Export Citation Format

Share Document