Isolation and Characterization of New Metschnikowia pulcherrima Strains as Producers of the Antimicrobial Pigment Pulcherrimin

2009 ◽  
Vol 64 (5-6) ◽  
pp. 405-410 ◽  
Author(s):  
Sezai Türkel ◽  
Beyza Ener

Metschnikowia pulcherrima is a highly effective biocontrol yeast due to its pigment pulcherrimin that accumulates in the cells and in the growth medium. Three different strains of M. pulcherrima were isolated from local grapes. The yeast isolates were characterized on the basis of their biochemical, physiological and ITS1-5.8 s rDNA-ITS2 region. Based on the obtained results, the M. pulcherrima isolates were identifi ed as new strains of M. pulcherrima. Strong antagonistic activities of the M. pulcherrima strains on the human pathogens Proteus vulgaris, Escherichia coli, Candida albicans, Candida parapsilosis, Candida krusei, and Trichosporon mucoides were determined. In addition, antagonistic effects of these M. pulcherrima strains were also tested against Aspergillus fl avus, Aspergillus fumigatus, Aspergillus niger, Trichoderma spp., Paecilomyces spp., and Bipolaris spp. and it was shown that the three different strains of M. pulcherrima also have an antagonistic effect on the growth of these fungal species at different extents. This study showed that all three strains of M. pulcherrima produce the same amount of the pigment pulcherrimin, but their antimicrobial activities on different microorganisms show important variations

2019 ◽  
Vol 24 (2) ◽  
pp. 7-16
Author(s):  
Nabin Rana ◽  
Saraswoti Khadka ◽  
Bishnu Prasad Marasini ◽  
Bishnu Joshi ◽  
Pramod Poudel ◽  
...  

 Realizing myxobacteria as a potential source of antimicrobial metabolites, we pursued research to isolate myxobacteria showing antimicrobial properties. We have successfully isolated three strains (NR-1, NR-2, NR-3) using the Escherichia coli baiting technique. These isolates showed typical myxobacterial growth characteristics. Phylogenetic analysis showed that all the strains (NR-1, NR-2, NR-3) belong to the family Archangiaceae, suborder Cystobacterineae, and order Myxococcales. Furthermore, 16S rRNA gene sequence similarity searched through BLAST revealed that strain NR-1 showed the closest similarity (91.8 %) to the type strain Vitiosangium cumulatum (NR-156939), NR-2 showed (98.8 %) to the type of Cystobacter badius (NR-043940), and NR-3 showed the closest similarity (83.5 %) to the type of strain Cystobacter fuscus (KP-306730). All isolates showed better growth in 0.5-1 % NaCl and pH around 7.0, whereas no growth was observed at pH 9.0 and below 5.0. All strains showed better growth at 32° C and hydrolyzed starch, whereas casein was efficiently hydrolyzed by NR-1 and NR-2. Besides, preliminary antimicrobial tests from crude extracts showed activities against Gram-positive, Gram-negative bacteria, and fungi. Our findings suggest that the arcane soil habitats of Nepal harbor myxobacteria with the capability to produce diverse antimicrobial activities that may be explored to overcome the rapidly rising global concern about antibiotic resistance.


2009 ◽  
Vol 2 (1) ◽  
pp. 178-185
Author(s):  
M. Akhand ◽  
M. A. A. Al-Bari ◽  
M. A. Islam ◽  
Proma Khondkar

A new actinomycete strain was isolated from Western part of Bangladesh and identified as a new Streptomyces species on the basis of its morphological, biochemical, cultural characteristics and 16S rRNA data. The present paper describes the isolation and characterization of compound 1 from this new Streptomyces species with the help of various chemical and spectroscopic methods. Antimicrobial activity of compound 1 was tested by disc diffusion assay method and compared with that of standard antibiotics (Kanamycin for antibacterial activity and Nystatin for antifungal activity). The compound has been found to exhibit moderate to strong antimicrobial activity against the test organisms. Cytotoxicity of the compound 1 and the pet. ether extract of Czapek Dox (alkaline) broth of Streptomyces species was evaluated in brine shrimp bioassay with LC50 values of 23.85 µg/ml (ppm) and 19.95 µg/ml (ppm), respectively. Keywords: Streptomyces; Antimicrobial activity; Cytotoxicity. © 2010 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v2i1.3079                  J. Sci. Res. 2 (1), 178-185 (2010)  


2021 ◽  
Vol 14 (4) ◽  
pp. 1600-1606
Author(s):  
T Punithavalli

Nowadays, unlimited use of antibiotics and preservatives have become a big concern regarding the human health which turn the interest of biotech industries into their research on biologically active molecules from probiotic microbes, since they are nontoxic and suitable for many safer applications. On this background, the present investigation focused on the characterization of a bacteriocin from a Lactobacillus strain. The characterization of a bacteriocin was done using a Lactiplantibacillus plantarum MDP 5 isolated from the local markets of Puducherry and production was performed under standardized cultural conditions. The study on the maximum recovery of bacteriocin using ammonium sulphate precipitation method revealed that the 60% saturation rate evidenced highest activity of 6500 AU/ml with 4.113g/L dry weight followed by the purification was done with RP-HPLC method using C18 column. The purified bacteriocin revealed a novel molecular weight of 22 kDa with the help of SDS-PAGE which has not been reported from Lactobacillus species. Further, the purified bacteriocin evidenced appreciable antimicrobial activities against all the tested human bacterial pathogens of this study. The highest antimicrobial activity was recorded against Escherichia coli MTCC 443 followed by Staphylococcus aureus MTCC 96, Vibrio parahemolyticus MTCC 451, Enterococcus faecalis MTCC 9845, Pseudomonas aeruginosa MTCC 741 and Klebsiella pneumoniae MTCC 109 in the concentrations of 8AU/ml, 16AU/ml, 32AU/ml, 64AU/ml, 256AU/ml and 512AU/ml, respectively. From the overall observation, this study explored a novel bacteriocin purified from a probiotic bacterium represented potential antimicrobial activities against many human pathogens which suggesting its possible use for the safe therapeutic applications.


2019 ◽  
Vol 15 (4) ◽  
pp. 427-436
Author(s):  
Mahadevan Subramaniyan ◽  
Vijayakumar Subramaniyan ◽  
Arulmozhi Praveenkumar

Background: Infectious diseases are major leading cause of death in all parts of the world, because of the appearance of new multi drug resistant microbes. Therefore, the discovery of potential drug for effective treatment will help the slaughter of the microbes. The aim of the present study is to evaluate the presence of photochemical and antimicrobial activities of various crude extracts of leaves, fruits and root bark of Atalantia monophylla and Atalantia racemosa against human pathogens by using well diffusion method. Methods: Antimicrobial properties of the various extracts of Atalantia monophylla and Atalantia racemosa were studied against some human pathogenic microbes such as Gram-positive Bacteria, (Bacillus subtilis, Bacillus cereus, Staphylococcus aureus) Gram-negative Bacteria (Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli) and human opportunistic fungal pathogens (Candida albicans and Aspergillus niger). All the extracts were comparable with standard drugs (Ciprofloxacin, Gentamicin, Nystatin. and Amphotericin B). Minimum inhibitory concentration (MIC), minimum bactericidal /fungicidal concentration (MBC/MFC) values were determined through a microdilution method. The phytochemical analysis of these plant extracts were carried out using standard mthods. Results: Methanolic leaf extract of A. monophylla has showed excellent antimicrobial activity against S. aureus (40mm). As well, the A. racemosa methanolic leaf extract shows notable inhibitory activity against S. aureus (38mm). At the same time, the least inhibition was observed in aqueous extract of A. monophylla against E.coli (9mm). The MIC ranged from 0.78 µg/mL to 50 µg/mL and MBC/MFC 1.56 to 50 µg/mL were recorded. Phytochemical analysis of alkaloids, steroids, saponins, flavonoids, tannins, terpenoids, phenolics and cardiae glycoside were recorded in various extracts of A. monophylla and A. racemosa respectively. Flavonoids, phenolics and cardiac glycoside were present only in methonalic leaf extract of A. monophylla. Conclusion: The result of this study concluded that methanolic leaf extract has possessed novel compounds with significant antimicrobial properties. Hence, we recommend this plant for further studies on the isolation and characterization of that lead antimicrobial potential molecule.


1978 ◽  
Vol 33 (1-2) ◽  
pp. 120-123 ◽  
Author(s):  
Hartmut Blecher ◽  
Renate Blecher ◽  
Rudolf Müller ◽  
Franz Lingens

Abstract Five different strains of bacteria ultilizing antipyrine as sole source of carbon were isolated from soil. It was shown by morphological and physiological examinations, that the new isolates are closely related to strains selected with the herbicide chloridazon. A ll of these bacteria are charac­ terized by special features and cannot be classified according to Bergey’s Manual of Determinative Bacteriology.Part of the strains which were selected with antipyrine not only grow with antipyrine but also with chloridazon. The others cannot be grown on chloridazon. However, resting cells of the latter group convert chloridazon to its catechol derivative (5-amino-4-chloro-2 (2,3-dihydroxyphenyl) -3 (2H)-pyridazinone). In these bacteria a catechol-2,3-dioxygenase (catechol: oxygen 2,3-oxido-reductase, EC 1.13.11.2) was found which readily catalyzes the cleavage of the catechol derivative of antipyrine (2,3-dimethyl-l-(2,3-dihydroxyphenyl)-pyrazolone (5)). The enzyme shows only slight activity with the corresponding derivative of chloridazon.


2011 ◽  
Vol 52 (2) ◽  
pp. 137-144 ◽  
Author(s):  
Krishna Kumar ◽  
N. Amaresan ◽  
S. Bhagat ◽  
K. Madhuri ◽  
R. C. Srivastava

2020 ◽  
pp. 139-147
Author(s):  
Lam Quoc Hung ◽  
◽  
Huong Minh Nguyen ◽  
Ta Thi Yen ◽  
Le Vinh Hoa ◽  
...  

In Vietnam and around the world, Staphylococcus aureus remains a major hazard of food safety and food poisoning. S. aureus is present in many places and easily contaminates food production during processing chains. In this study, we successfully isolated S. aureus strains from suspected samples of two food borne poisoning outbreaks in Ha Giang and Vinh Phuc in 2017 and 2018, respectively. The collected samples were examined for presence of staphylococcal enterotoxins (SEs) by using 3MTMTECRATM Staph Enterotoxin kit, from there all the samples were positive with SEs. Different strains of S. aureus were isolated and then confirmed by MALDI-TOF technique. Those strains then were stored in Brain heart solution with 15% glycerol until further analysis. Our results identified three STs, ST96, ST88 (spa type t7558), and ST72 (spa type t3092), were responsible for two outbreaks. Two virulence genes detected from the above strains were sea and sec. Furthermore, these strains are test for antibiotic resistance susceptibility with commonly antibiotics. Penicillin are found to be resisted by all three STs, in particularly, ST96 and ST88 are both resistant to erythromycin while ST72 is resistant to gentamicin. Taken together, our study highlights the usefulness of molecular characterization to study and monitor bacterial pathogens associated with food poisoning outbreaks in Vietnam.


2021 ◽  
Vol 4 (3) ◽  
pp. 1131-1136
Author(s):  
Vu Thi Huyen ◽  
Doan Thi Thuy Ai ◽  
Nguyen Thi Hien

The genus Dialium belongs to the Caesalpinioideae family, consisting of approximately 30 species distributed in the tropical regions. Secondary metabolites from the  Dialium genus have been reported to exhibit various biological activities including antioxidant, cytotoxicity and antimicrobial activities. This work describes the isolation and characterization of five compounds from the leaves of Dialium cochinchinense Pierre. Their structures were established by spectroscopic analysis, including MS and NMR spectra. Accordingly, the isolated compounds were identified to be lupeone (1), b-sitostenone (2), β-sitosterol (3), daucosterol (4), and dihydrokaempferide (5). To the best of our knowledge, this is the first report of the isolation of compounds 1 and 5 from the genus Dialium.


Author(s):  
R. Darsana ◽  
G. Chandrasehar

Red pepper is a spice vulnerable to fungal growth and mycotoxin contamination while in the field and post-harvest during storage. Storage fungi are omnipresent and colonize fast when moisture levels go up, ultimately leading to mycotoxin production. Stored samples of the whole, crushed and ground red pepper in the Southern Indian States and Maharashtra, India were examined to isolate and characterize the prevalent contaminant fungal species. The average moisture content was below 10% for all the red pepper samples and the average total fungal load was less than 1×104 CFU/g. Crushed red pepper showed higher fungal counts than ground and whole red pepper. The identified contaminant mycoflora belonged to the group; Aspergillus, Eurotium sp., Cladosporium sp., Eupenicillium sp., Penicillium sp., Miscellaneous fungi, Neosartorya sp., Curvularia sp., and Hyphopichia sp. Aflatoxigenic Aspergillus flavus was present only in 8.3% of the crushed and 2.54% of whole red pepper samples stored for more than two months.


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