Showing 5 results for Microbial Agent
Volume 0, Issue 0 (1-2024)
Abstract
Entomopathogenic fungi, Beauveria bassiana and Metarhizium anisopliae are important and effective biocontrol agents against arthropod pests. Compared to chemical insecticides, insect pests do not easily develop resistance against these fungi. In this study, the mortality and phenol-oxidase activity of the Helicoverpa armigera 3rd instar larvae were evaluated after exposure to the B. bassiana and M. anisopliae. The LC50 values for B. bassiana and M. anisopliae were 0.795 ×106, and 5.972 ×107 spore ml-1, respectively. LC30 and LC10 of either entomopathogenic fungi were injected into body of larves, then, 24 and 48 hours after injection, their hemolymph was extracted. After 24 h the highest and lowest phenol-oxidase activity was observed in LC30 of M. anisopliae, and LC10 of B. bassiana, respectively. After 48 h of infection, phenol-oxidase activity increased in all treatments. At the LC30 of M. anisopliae, the highest phenol-oxidase activity was recorded, and other treatments also showed a significant difference compared to the control. Five types of hemocytes including prohemocytes, plasmatocytes, granulocytes, onocytoids, and spherulocytes were identified in the hemolymph of larvae. The highest total hemocytes count (THC) was recorded in LC30 M. anisopliae at 9 h after initial infection. Our results showed that both fungi have the ability to affect phenol-oxidase enzyme activity. These microbial insecticides exhibited high potential for controlling the pest.
Volume 4, Issue 1 (2-2018)
Abstract
Aims: Many infectious diseases had traditionally been cured with herbal medicines. Antimicrobial agents are often produced synthetically to increase the food durability and quality. The purpose of this study was to determine the antimicrobial properties of the aqueous and alcoholic extracts of Allium schoenoprasum.
Materials & Methods: In this experimental study, after preparation Allium schoenoprasum samples, aqueous and alcoholic extracts were prepared and their minimum inhibitory concentration (MIC) was determined against Staphylococcus aureus, Bacillus cereus, Escherichia coli and Vibrio cholerae by micro broth dilution method. Erythromycin was used as the control.
Findings: The MIC of alcoholic and aqueous extracts of A. schoenoprasum was 16-256 and 32->256µg/ml, respectively and MBC of them were 32-256 and 64->256ug/ml, respectively. The A. schoenoprasum exhibited higher activity against S. aureus and B. cereus strains.
Conclusion: The extracts of A. schoenoprasum have antimicrobial effect on S. aureus, B. cereus, E. coli and V. cholerae strains in micro broth dilution method.
Volume 8, Issue 32 (10-2011)
Abstract
In the recent years, interest in the use of biodegradable biopolymers for packaging applications has raised. One of the potential uses of these biopolymers is for production of active packaging containing antimicrobials. In this review manuscript, has presented some examples for applications of these packaging materials for different foods and then has mentioned the different kinds of antimicrobial agents that may be incorporated in their formulations. Many factors are involved in designing the antimicrobial packaging system. Most factors are closely related to the chemical characteristics of antimicrobial agents, the nature of the food and target microorganisms that all will be discussed in this paper.
Muhammad Muhammad, Roswanira Abdul Wahab, Fahrul Zaman Huyop, Mohd Hefni Rusli, Syariffah Nuratiqah Syed Yaacob, Hwee Li Teo,
Volume 11, Issue 1 (1-2022)
Abstract
Fungal plant diseases can severely damage oil palm crops and compromise agricultural yields. To ensure a high crop yield while keeping the fungal pathogens at bay, microbial control to combat such diseases offers a more sustainable alternative to chemical control. It is safer to replace chemical fungicides with eco-friendly bio formulations containing living fungi or bacteria and their products to manage fungal infestations on plants, especially oil palm. This is because natural antagonistic microorganisms/substances form components of biofungicides and protect plants by various modes of action such as hyperparasitism, antibiosis and/or by induction of systemic resistance. Microbial agents’ application in managing fungal plant diseases, especially oil palm crop diseases, promises a safer and sustainable agricultural system to control fungal phytopathogens while ecologically less polluting. This article briefly describes the different bioformulations and the mechanism of action of microbial agents to manage fungal phytopathogens of crops, especially in oil palm. A summary of various merits and demerits of biofungicides over synthetic ones and the future outlooks are also highlighted. Bio-based microbial agents for controlling fungal phytopathogens, especially in oil palm plants, appear to be a promising fungal pest management approach considering the growing need for sustainable practices in the agronomic sector.
Volume 22, Issue 158 (3-2025)
Abstract
Nowadays food industry, investigating bioactivity of different plant extracts and essential oils as natural additives and quality enhancers plays a great role for responding to food related health issues and the need of safe products with improved overall quality according to consumer’s diverse taste. In present study, chemical composition along with the antioxidant and antimicrobial properties of the coriander essential oil were investigated. According to the gas chromatography-mass spectrometry (GC-MS) outputs, Linalool identified as the major component (52.40%) in the essential oil. Total phenol and flavonoid estimated about 75.60 mg GAE/g and 715.33 mg QE/g essential oil while antioxidant capacity of the substance evaluated and showed that unlike ABTS assay, essential oil in DPPH assay reached a higher level of radical scavenging slightly more than %50 (%51.95) at same concentration of 1000 ppm. The smallest and largest diameters of inhibition zones at disk diffusion agar method belonged to Shigella dysenteriae (14.10 mm) and Bacillus cereus (24 mm). Minimum inhibitory concentrations (MIC) against Escherichia coli, Shigella dysenteriae, Salmonella typhi, Staphylococcus aureus, Listeria monocytogenes and Bacillus cereus estimated 4, 8, 4, 2, 2 and 2 mg/mL while minimum bactericidal concentrations (MBC) 256, 512, 256, 256, 128, 128 mg/mL respectively. Based on the overall results, coriander seed essential oil at certain concentrations could have a high potential as a safe food additive and a strong preservative for application in the industry.
