Genetic variability in the ITS and IGS regions of the ribosomal DNA of Acremonium cavaraeanum exhibiting antimicrobial activity

Abstract

ABSTRACT. Endophytic microorganisms represent promising alternatives for obtaining new drugs of biotechnological importance. In this study, the endophytic species Acremonium cavaraeanum (A1a) isolated from Cocos nucifera was cultivated for the production of secondary metabolites, and its extracts and fractions were evaluated by the dilution method (MIC). The EtOAc extracts and MeOH fractions were tested against Gram-positive and -negative bacteria, and had an MIC of 125 µg/mL when evaluated in the EtOAc extract (EBI). The EtOAc extract (EBII) had an MIC of 62.25 µg/mL for Staphylococcus aureus and an MIC between 125 and 250 µg/mL for Gram-negative bacteria. The methanolic fractions showed activity with MIC between 125 and 250 µg/mL for all bacteria tested. The IGS region of the rDNA repeat unit of genomic DNA was analyzed by PCR/RFLPs, including endonucleases PstI, BamHII, HinfI, and EcoRI. The physical maps showed different restriction sites for the 6 Acremonium sp isolates, and revealed 5 RFLP patterns. The results showed that isolates of the same Acremonium species exhibited variation in this specific region. The sequences of ITS1-5.8S-ITS2 regions were aligned by Clustal W using the neighbor joining method, which grouped the isolates into 5 distinct clusters. This study aimed to evaluate the genetic diversity of A. cavaraeanum crops exhibiting antibacterial activity. The results of this study indicate that different fungal genetic isolates have biotechnological potential for the production of active bio-compounds against several human pathogens.

Two Dibenzoquinones from the Fungus Acremonium cavaraeanum

“…It was also reported that Acremonium cavaraeanum from Cocos nucifera has antibacterial activity [15]. It has exhibited antimicrobial activity against Gram-positive bacteria and was inefficient against Gram-negative bacteria [15]. In this paper, the fungal strain Acremonium cavaraeanum CA022 was isolated from the fruiting bodies of an ascomyceteous fungus Shiraia bambusicola, which is known to grow in some provinces south of the Yangtze River of China and in Japan [16].…”

“…For example, pyrrocidines A from Acremonium zeae presented inhibitory effects on various pathogens [13]. It was also reported that Acremonium cavaraeanum from Cocos nucifera has antibacterial activity [15]. It has exhibited antimicrobial activity against Gram-positive bacteria and was inefficient against Gram-negative bacteria [15].…”

An efficient marker recycling system for sequential gene deletion in a deep sea-derived fungus Acremonium sp. HDN16-126

“…Chemical and pharmaceutical studies on Acremonium spp. have proven that they are also prolific producers of other secondary metabolites including steroids, terpenoids, metroterprnoids, polyketides, alkaloids and peptides [ [5] , [6] , [7] ]. However, the vast majority of the biosynthetic machinery of those metabolites as well as physiological and biochemical effectors of this genus are still obscure.…”