Biotechnological Journal of Environmental Microbiology
Volume:2 Issue: 1, Spring 2023

This study delves into the impact of seasonal variations on the diversity of endophytic fungi inhabiting the foliage of Grevillea robusta trees along highways in Hawassa City, Ethiopia. With 765 fungal isolates categorized into 73 distinct morphotaxa, 90.41% were identified across eight known genera, leaving 9.58% unidentified. Notably, Phoma and Pestalotiopsis emerged as the most diverse genera, presenting 13 and 11 morphotaxa respectively, while Alternaria and Xylaria showed lower diversity with 3 and 2 morphotaxa each. The research unveiled heightened fungal counts and diversity in trees situated in more polluted environments, leaves sampled during dry seasons, those exhibiting signs of disease, lower leaf sections, and midrib samples. These findings underscore the rich assortment of endophytic fungi associated with Grevillea robusta leaves within roadside plantations in Hawassa City, emphasizing the need for further exploration of this fungal community's dynamics. Understanding the pivotal role of these endophytic fungi in tree health, ecosystem resilience, and potential applications in agriculture, forestry, and biotechnology remains imperative.

Actinomycetes are known as the largest reservoir of natural antibiotics in the world. For this reason, due to their ability to produce various antibiotics and other compounds of therapeutic importance, they are considered the golden microorganisms of the 21st century. The purpose of this research is the isolation and molecular identification of actinomycetes with antimicrobial properties from agricultural soils in the native areas of Guilan province. Soil samples were collected from the southwestern agricultural areas of Guilan province. Serial dilution was used to isolate actinomycetes. Then the morphological, physiological, and biochemical identification of the samples was done and finally, the molecular identification of the isolates was done using 16S rRNA sequencing and phylogenetic analysis. Antimicrobial activity was investigated against pathogenic microorganisms. A total of 14 isolates were identified.2 isolates with more antimicrobial properties were selected. Based on the results of phylogenetic studies and 16S rRNA sequencing, Amycolatopsis roodepoortensis strain EA7 with 99.63% confidence, and Streptomyces microflaveus strain EA6 with 93.92% confidence were identified. The isolated bacteria had more antimicrobial activity against Gram-positive pathogenic microorganisms Staphylococcus aureus and standard sample Staphylococcus aureus PTCC 1112. This research is the first report on the identification of actinomycetes with antimicrobial properties in the agricultural soils of the southwestern regions of Guilan province located in the Alborz mountains. The identification of the rare strain of Amycolatopsis roodepoortensis strain EA7 from the northern regions of Iran makes the soils of these regions very valuable.

Seductive and impressive applications of samarium oxide based materials in semiconductor science, created an interest to synthesize and study their physical properties. Therefore, after preparing pure samarium oxide and graphene/samarium oxide powders through hydrothermal technique; with use of X-Ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and UV-Visible spectrophotometry; structural, optical, and morphological properties of the samples have been evaluated. Using XRD, lattice constants and some related structural parameters were determined. Variation of optical band gap has been calculated too, with aiding absorbance, The XRD data revealed prevailed cubic samarium oxide phase in both samples, even though a sharp diffraction peak of graphene was attended in graphene/samarium oxide sample. SEM, Raman, and FTIR analysis showed the effects of graphene addition on main lattice of samarium oxide. Furthermore, the decrease of optical band gap due to graphene was also notable.

Listeria monocytogenes, as one of the foodborne pathogens, is a causative agent of listeriosis. Listeria is ubiquitous in the environment and can produce biofilms in the food production environment and thus contaminate ready-to-eat (RTE) products, which are typically consumed raw or without further processing. L. monocytogenes is an adaptable environmental bacterium. One of the most important characteristics of L. monocytogenes is its cold tolerance and resistance to high salt concentrations and low pH. On the other hand, this bacterium is an important pathogen in pregnant women, neonates, elderly individuals, immunocompromised individuals and patients with cancer. Spontaneous abortion is the loss of a fetus before the 20th week of pregnancy, when occurring naturally without any surgical or phar maceutical intervention. Based on previous studies, it appears that L. monocytogenes incidence is high among pregnant women. It can be concluded that, pregnant women and their health care providers should be informed about listeriosis during pregnancy.

Curcumin, a natural product of turmeric, is known for its antibacterial and antifungal properties. Candida albicans is a major fungal pathogen with high mortality rate, particularly in immunocompromised patients. This study aimed to evaluate the effect of curcumin encapsulated in nanoparticles (polymersomes) in combination with fluconazole on the expression of the MDRI gene in drug-resistant isolates of C. albicans. This descriptive cross-sectional study involved obtaining 50 clinical samples, from women with vulvovaginal infections at Al-Zahra hospital (Rasht, Iran). After identifying the strains, resistance to fluconazole was assessed using disc diffusion and broth dilution methods. Six fluconazole-resistant isolates of C. albicans were treated with ½ MIC fluconazole (control) alone and in combination with curcumin encapsulated in nanoparticles. After 24 hours, the two cell groups were cultured on Sabouraud dextrose agar (SDA) to estimate the cell death rate. The expression of the MDR1 gene was quantitatively investigated using the qRT-PCR method in treated and untreated isolates. Our finding indicated that combined therapy with ½ MIC fluconazole and curcumin encapsulated in nanoparticles (at a concentration of 400µg/ml) reduced fungal growth by up to 50% within during 24 hours. In treated cells, qRT-PCR analysis revealed a decrease in MDR1 gene expression compared to untreated cells. Curcumin appears to enhance the effectiveness of fluconazole in fluconazole-resistant isolates by reducing MDR1 gene expression.

Nisin is an antimicrobial peptide composed of 34 amino acid residues. Due to the presence of lanthionine amino acids, it is classified as a lantibiotics and demonstrates effectiveness against numerous pathogenic microorganisms. Although its effectiveness is greatly reduced in various clinical and environmental settings due to its reaction with other compounds. New methods may be able to solve this problem in microcapsules and control their release. The use of fluoride in toothpaste helps control factors that contribute to tooth decay, one of the most common diseases that humans face in their lifetime. The aim of this study was to investigate the effects of free and encapsulated nisin on Streptococcus mutans and its growth kinetics. Nisin was encapsulated in lecithin and alginate liposomes using the thin-layer hydration method. The size and distribution of nisin microliposomes were determined using scanning electron microscopy and Dynamic Light Scattering (DLS) techniques. To determine the minimum inhibitory concentration (MIC) of nisin microliposomes and free nisin on S. mutans at various concentrations ranging from 0.78 to 25 μg/ml. To investigate the growth kinetics, the growth rate or inhibition of S. mutans was studied by exposing it to concentrations equivalent to the MIC over a 50-hour period at a wavelength of 600 nm. The study compared the effects of nisin and nisin microcapsules to those of the antibiotics amoxicillin and penicillin. Microencapsulated nisin reduced the growth of planktonic strains of S. mutans more effectively than free nisin. Nisin microliposomes at a concentration of 6.25 μg/ml inhibited the growth of S. mutans, whereas the inhibitory effects of free nisin were observed at a concentration of 12.5 μg/ml in both clinical and standard strains. Additionally, there was a significant reduction in the production of lactic acid by S. mutans. Based on the current findings regarding the inhibitory effects and durability of nisin micro encapsules, it is plausible that this compound could be utilized in combination with other methods to control tooth decay and enhance the anti-caries efficacy.