Isolation and Characterization of Soil Myxobacteria from Nepal

Abstract

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.

The effect of seaweed extract on tomato plant growth, productivity and soil

“…Upon review of the 14 bacterial families that were significantly enriched by SWE treatment, we found certain members to have functions associated with enhanced soil properties and plant growth (Muhammad and Shahida 2006;Sgroy et al 2009;Miransari 2013;Rolli et al 2015;Shan et al 2018;Rana et al 2019). For example, some of the species that belong to the family Nakamurellaceae have been associated with symbiotic endophytes (Whitman 2015;Singh and Dubey 2018;Nouioui et al 2019).…”

Suppression of predominant interfering bacteria in the purification process of myxobacteria

“…In this study, the combined ultrasonication and heat treatment was applied as a combinatorial purification strategy and revealed enough efficiency for the various types of contaminants; especially root symbiotic bacteria namely Microvirga, which is among the dominant impurities in the culture of myxobacteria. Purification protocol with the aid of antibiotic treatments can also be useful provided that the mature myxospores are present (31). By this approach, the isolation of Myxococcus from soil could be accelerated by plating the soil samples directly on a medium containing antibiotics which inhibit the growth of non-sporulating cells (32).…”

“…Purification protocol with the aid of antibiotic treatments can also be useful provided that the mature myxospores are present ( 31 ). By this approach, the isolation of Myxococcus from soil could be accelerated by plating the soil samples directly on a medium containing antibiotics which inhibit the growth of non-sporulating cells ( 32 ).…”

Fermentation and Extraction of Antibacterial Metabolite Using Streptomyces spp. Isolated from Taplejung, Nepal

“…The genus Streptomyces is responsible for the production of 60 % of the antibiotics (Singh et al, 2005). The demand for new antimicrobial agents is high because of the emergence of new multidrug resistance in common pathogens (Rana et al, 2019), and the potential of use of multidrug-resistant pathogens in bioterrorism (Spellberg et al, 2004). Antibiotic-resistant bacteria have challenged the treatment of infectious diseases which are still the second leading cause of death worldwide (Luzhetsky et al, 2007).…”