Influence of Trichoderma spp on Macrophoma theicola branch canker disease in South Indian tea gardens, India

Author(s):  
Jeyaraman Mareeswaran

Abstract Branch canker disease caused by the fungus Macrophoma theicola is a major stem disease that reduces the yield of south Indian tea plantations. Hence the present study aimed to assess the efficacy of the biocontrol agent Trichoderma spp against various isolates of Macrophoma spp. For this matter, different tea-growing regions of south India were surveyed for the isolation and characterization of Macrophoma spp. Then, fungal biocontrol strains (Trichoderma viride, Trichoderma atroviride, Trichoderma harzianum, and Gliocladium virens) were procured from microbial type culture collection Centre (MTCC) to screen their antagonistic potential on different isolates Macrophoma spp. The spores of Macrophoma spp were examined through a light microscope and identified by their peculiar morphological features such as non-septum pycnidiospores present in the sac and oval shape spore with stalk and confirmed using 18S rRNA gene sequence. The results revealed that the biocontrol G. virens followed by T. harzianum showed a higher inhibitory effect on different isolates of Macrophoma spp in the dual plate and culture filtrate studies. In the well diffusion method, the fungal biocontrol agents were found to be exhibit non-significant differences on different isolates of branch canker pathogen. The hyphal interactions studies showed that the pathogenic hyphal wall shrunk and penetrated by the interaction of G. virens.

2012 ◽  
Vol 1 (8) ◽  
pp. 217-220 ◽  
Author(s):  
BE Ravi Shankara ◽  
YL Ramachandra ◽  
S Sundara Rajan ◽  
J Preetham ◽  
PS Sujan Ganapathy

The leaf galls of Terminalia chebula is used widely as Karkatasringi in south Indian markets. Karkatashringi is an important crude drug employed in various indigenous systems of medicine against several diseases and the drug has diverse medicinal properties. The present study was carried out to understand the antimicrobial activity of various extracts. The antibacterial activity of T. chebula (leaf gall) was evaluated against ten bacterial strains including Gram-positive and Gram-negative bacteria using the agar-well diffusion method. Among the two extracts tested, the ethanol extract presented the best results against all the bacteria while aqueous extract showed moderate inhibition of the microbial growth. Each extract is unique against different microorganisms; Staphylococcus aureus was more susceptible to both extract among the tested organisms, whereas Serratia marcescens and Proteus mirabilis were less susceptible for ethanol and aqueous extract respectively. The inhibitory effect of the extracts was compared with standard antibiotic Ciprofloxacin.DOI: http://dx.doi.org/10.3329/icpj.v1i8.11254 International Current Pharmaceutical Journal 2012, 1(8): 217-220 


Author(s):  
Priscilla Mercy Anitha D ◽  
Periyar Selvam Sellamuthu ◽  
Seema A Kulkarni

Objective: The aim of this study was to isolate, characterize and identify the potential lactic acid bacteria from fermented ragi millet (Eleusine coracana).Methods: A total of 177 isolates were isolated from the fermented ragi porridge. All the isolates were subjected to preliminary screening (Gram staining and catalase test). The physiological features of the probiotic isolates such as tolerance to pH (2.0, 4.0), phenol (0.3%, 0.5%) and bile salt (0.3%) were carried out. Antibiotic susceptibility test was performed using disc diffusion method. Free radical scavenging assay was conducted by 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. The isolates were further characterized for their cholesterol-lowering property. Based on their survival ability and biochemical tests, the selected potent isolates were identified by 16S rRNA gene sequence by PCR and phylogenetic analysis. The 16S rRNA gene sequencing confirmed that isolates were Lactococcus lactis RS01, Lactobacillus plantarum RS09, Lactobacillus plantarum RS16 and Lactobacillus plantarum RS23.Results: Twenty five isolates were screened from the 177 total isolates based on their morphological and biochemical characteristics (Gram staining and catalase test). All the isolates showed tolerance against acid, phenol and bile salts. However, RS09 and RS23 exhibited maximum viable count and demonstrated good tolerance at the end of 3 h. Highest antioxidant activity was recorded in RS09 ranging from 32-85%. Among the tested strains, the degradation rate of supernatants, RS09 (61.9%), RS23 (60%) and RS01 (58.97%) and RS16 (56.2%) showed the highest cholesterol assimilation rate. In addition, they also found to be resistant and sensitive to few antibiotics.Conclusion: Based on the obtained results, these isolates are ideal in vitro probiotic strains and can be used further for in vivo evaluation.


Author(s):  
Mezeal Ali Intesar, Ibraheem Jameel Liqaa ,Mizil Nghamish Sh

In vitro testing, antagonistic capability of Trichoderma spp. obtained from the rhizosphere of tomato showed inhibitory effect against growth of   R. solani ,  few biological control agents have achieved success under field conditions. Among the hundreds of organisms identified as potential biological disease control agent, only few have resulted in proving commercially acceptable control of these diseases. Rhizoctonia solani were  isolate from a naturally occurring epidemic of damping-off tomato plants grown in Kut governorate, Iraq,In vitro, of  9 isolates belonging to the fungus Trichoderma spp.  5 isolates belonging to the fungus T. viride while diagnosed 4 isolates belong to the fungus T. harzianum  isolated from the rhizosphere of tomato plants. Both T. viride and T. harzianum had antagonistic effect on R.solani isolates . Results showed that ability of six isolates of the pathogenic fungus to damping   of the tomato plant seedlings under greenhouse conditions ,   isolates R.solani-M  and R.solani-H showed the largest percentage of the disease compared with other isolates( 30.2 and 32.1%) respectively, while the effect of isolate R.solani-A was daming  of  21.9% from tomato seedlings Pre-emergence.  


Author(s):  
Mohamed Ali Kassem ◽  
Amal Eissa Saafan ◽  
Faten Bayomy ◽  
Ahmed Osama El-Gendy

Background and Objectives: Bacteriocins are considered alternative non-conventional antimicrobials produced by certain bacteria with activity against closely related species. The present study focuses on screening, characterization, and partial purification of bacteriocins produced by Staphylococcus sp. isolated from different clinical sources such as pus and blood. Materials and Methods: A total of 100 Staphylococcus isolates were screened for bacteriocin production using spot on lawn assay and agar diffusion method against five indicator bacteria. Bacteriocins from five selected highly active isolates were subjected to proteinase-K enzyme, different pH, and heating at different temperatures, and investigated the stabilities of their antimicrobials. Two selected isolates, MK65 and MK88, were molecularly identified by 16S rRNA gene sequencing, explored for the presence of 18 bacteriocin genes, and liquid chromatography-high resolution electrospray ionization mass spectrometry (LC-HRESIMS) was used to identify their different metabolites. Results: Twenty isolates exhibited inhibitory effect against at least one indicator bacteria. Micrococcus luteus ATCC 4698 showed the highest sensitivity to such bacteriocins. Proteinase K, acidic pH, and heating at 100°C triggered marked activity inhibition. However, amylase enzyme, alkaline pH, and heating at 80°C caused trivial effects. Four out of eighteen bacteriocin genes were detected using PCR. Fermentation, partial purification, and LC-HRESIMS of total protein extracts of two selected isolates, MK65 and MK88, revealed the production of different antimicrobial peptides. Conclusion: To the best of our knowledge, this is the first study to report the production of micrococcin and α-circulocin from Staphylococcus aureus MK65 and the production of amonabactin from Staphylococcus epidermidis MK88.


2020 ◽  
Vol 82 (6) ◽  
pp. 54-63
Author(s):  
M.Ya. Vortman ◽  
◽  
Yu.B. Pysmenna ◽  
A.I. Chuenko ◽  
D.R. Abdulina ◽  
...  

Biocides are widely used in medicine and various industries to protect against a number of harmful microorganisms. Organic quaternary ammonium and guanidine-containing compounds, the biological action of which is based on membrane-toxic properties, are used as bactericidal preparations. The aim of this work was to study the bactericidal and fungicidal activities of the synthesized oligomeric alkylsubstituted guanidinium bromides with different radicals -C3H7, -C7H15, -C10H21, against different isolates of heterotrophic bacteria and microscopic fungi. Methods. The synthesis of alkyl-substituted guanidiniumcontaining oligomers was performed in two stages. In the first stage, alkyl-substituted guanidine was obtained by the reaction of guanidine, previously converted by alkali from the salt form to the base form by the base and alkyl bromides (Alk=-C3H7 (propyl), -C7H15 (heptyl), -C10H21 (decyl)) in methanol at a temperature of 50°C and a molar ratio of 1:1. The second carried out the reaction between aromatic oligoepoxide DER-331 and alkyl-substituted guanidine in methanol at a temperature of 50°C for 2–3 hours and a molar ratio of 1:2. Bacteria were grown on meat-peptone agar for 48 hours at a temperature of 28±2°С. Test cultures of micromycetes were cultured on agar beer wort (6°B), incubated for 14 days in a thermostat at a temperature of 28±2°C. Antimicrobial activity of newly synthesized alkyl-substituted guanidinium-containing oligomers was determined by standard disco-diffusion method (method of disks on agar) and fungicidal activity was determined by the method of holes in agar. Results. Oligomeric alkylsubstituted guanidinium bromides with different radicals composed -C3H7, -C7H15, -C10H21- synthesized by the reaction of guanidine alkyl bromides with aromatic oligoepoxydes. It was found that alkyl-substituted guanidinium-containing oligomers at a concentration of 1–3% inhibited the growth of Escherichia coli 475, Pseudomonas aeruginosa 465, Klebsiella pneumonia 479, Pseudomonas pseudoalcaligenes 109, Staphylococcus aureus 451, E. faecalis 422, Rhodococcus erythropolis 102, Bacillus subtilis 138 and most of the studied micromycetes – Aureobasidium pullulans F-41430, Paecilomyces variotii F-41432, Penicillium funiculosum F-41435, Penicillium ochrochloron F-41431, Scopulariopsis brevicaulis F-41434, Trichoderma viride F-41437, Candida albicans F-41441, Aspergillus flavus F-41442, Aspergillus niger F-41448, Penicillium sp. F-41447. Conclusions. Antimicrobial and fungicidal properties significantly depend on the length of the alkyl radical, with increasing of its length the diameter of the zone of bacterial and micromycetes growth retardation increases.10.15407/microbiolj82.06.054


2020 ◽  
Vol 11 ◽  
pp. 37-43
Author(s):  
Prof. Teodora P. Popova ◽  
Toshka Petrova ◽  
Ignat Ignatov ◽  
Stoil Karadzhov

The antimicrobial action of the dietary supplement Oxidal® was tested using the classic Bauer and Kirby agar-gel diffusion method. Clinical and reference strains of Staphylococcus aureus and Escherichia coli were used in the studies. The tested dietary supplement showed a well-pronounced inhibitory effect against the microbial strains commensurable with that of the broad-spectrum chemotherapeutic agent Enrofloxacin and showed even higher activity than the broad spectrum antibiotic Thiamphenicol. The proven inhibitory effect of the tested dietary supplement against the examined pathogenic bacteria is in accordance with the established clinical effectiveness standards for antimicrobial agents.


2021 ◽  
pp. 088391152110142
Author(s):  
Velu Gomathy ◽  
Venkatesan Manigandan ◽  
Narasimman Vignesh ◽  
Aavula Thabitha ◽  
Ramachandran Saravanan

Biofilms play a key role in infectious diseases, as they may form on the surface and persist after treatment with various antimicrobial agents. The Staphylococcus aureus, Klebsiella pneumoniae, S. typhimurium, P. aeruginosa, and Escherichia coli most frequently associated with medical devices. Chitosan sulphate from marine litter (SCH-MW) was extracted and the mineral components were determined using atomic absorption spectroscopy (AAS). The degree of deacetylation (DA) of SCH was predicted 50% and 33.3% in crab and shrimp waste respectively. The elucidation of the structure of the SCH-MW was portrayed using FT-IR and 1H-NMR spectroscopy. The molecular mass of SCH-MW was determined with Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF). The teratogenicity of SCH-MW was characterized by the zebrafish embryo (ZFE) model. Antimicrobial activity of SCH-MW was tested with the agar well diffusion method; the inhibitory effect of SCH-MW on biofilm formation was assessed in 96 flat well polystyrene plates. The result revealed that a low concentration of crab-sulfated chitosan inhibited bacterial growth and significantly reduced the anti-biofilm activity of gram-negative and gram-positive bacteria relatively to shrimp. It is potentially against the biofilm formation of pathogenic bacteria.


2021 ◽  
Vol 9 (7) ◽  
pp. 1346
Author(s):  
Mariana Petkova ◽  
Petya Stefanova ◽  
Velitchka Gotcheva ◽  
Angel Angelov

Traditional sourdoughs in Bulgaria were almost extinct during the centralized food production system. However, a rapidly developing trend of sourdough revival in the country is setting the demand for increased production and use of commercial starter cultures. The selection of strains for such cultures is based on geographical specificity and beneficial technological properties. In this connection, the aim of this study was to isolate, identify and characterize lactic acid bacteria (LAB) and yeasts from typical Bulgarian sourdoughs for the selection of strains for commercial sourdough starter cultures. Twelve samples of typical Bulgarian sourdoughs were collected from different geographical locations. All samples were analyzed for pH, total titratable acidity and dry matter content. Enumeration of LAB and yeast was also carried out. Molecular identification by 16S rDNA sequence analysis was performed for 167 LAB isolates, and 106 yeast strains were identified by ITS1-5.8S-ITS2 rRNA gene partial sequence analysis. The LAB strains were characterized according to their amylolytic and proteolytic activity and acidification capacity, and 11 strains were selected for further testing of their antimicrobial properties. The strains with the most pronounced antibacterial and antifungal activity are listed as recommended candidates for the development of starter cultures for sourdoughs or other food products.


2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Otun Saha ◽  
Nadira Naznin Rakhi ◽  
Arif Istiaq ◽  
Israt Islam ◽  
Munawar Sultana ◽  
...  

Introduction. Effective sanitation strategies for poultry farms require an appropriate selection of the disinfectant based on the contaminants present and their sensitivity to the disinfectants. Aim. The current study investigated the prevalence of streptococci/micrococci in poultry farms of Bangladesh and the efficacy of commercial disinfectants (Savlon, Lysol, Quatovet, Virkon S, and Virocid) along with alcohol against these pathogens to adopt appropriate strategies. Materials and Methods. Conventional approaches and the 16S rRNA gene sequencing were performed to confirm the isolates at the species level along with microtiter biofilm assay to determine their biofilm-forming ability. Efficacy of the disinfectants was tested against those isolates using agar well diffusion and minimum inhibitory concentration (MIC) test by broth dilution method using different dilutions of the disinfectants. Results. Staphylococcus lentus (n = 32), Micrococcus luteus (n = 7), and Micrococcus aloeverae (n = 4) were confirmed among 102 presumptively screened streptococci/micrococci isolates from 43 samples. No single disinfectant showed equally high efficacy against all three bacterial species in agar well diffusion test, although Virocid showed the lowest MIC against all three of them. Lysol was least effective among the commercial disinfectants by both MIC and diffusion method, although each commercial disinfectant was more effective than alcohol. Considering both the average diameter of the inhibition zones and the MIC values, efficacy can be interpreted as Virocid > Quatovet > Savlon > Virkon S > Lysol. Although the efficacy decreased with decreasing concentration, the disinfectants retained a satisfactory level of efficacy at 50% concentration. Among test pathogens, M. aloeverae was the most sensitive to the disinfectants and the weakest biofilm producers, whereas 4/14 S. lentus and 1/5 M. luteus were strong biofilm producers, which may cause more reduction in the efficacy in environmental conditions. Conclusion. As no ideal disinfectant was found in the study, the efficacy of the disinfectants should be routinely evaluated and validated to ensure the sanitation standards in the poultry sector.


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