Phylogenetic diversity and activity screening of cultivable actinobacteria isolated from marine sponges and associated environments from the western coast of India

Abstract

25Phylogenetic diversity of cultivable actinobacteria isolated from sponges and associated 26 environments of intertidal zones, along the northern parts of west coast of India, were studied 27 using 16S rRNA gene sequences. A subset of actinobacteria were screened for three activities, 28 namely predatory behavior, antibacterial activity and enzyme inhibition. We recovered 207 29 isolates of actinobacteria belonging to 16 families and 25 genera, which could be attributed to 30 55 putative species using Poisson Tree Processes and 60 putative species based on Bayesian 31Poisson Tree Processes. Although the trends in the discovery of actinobacterial genera isolated 32 from sponges was consistent with previous studies from different study areas, we provide first 33 report of six actinobacterial species from sponges. We observed widespread non-obligate 34 epibiotic predatory behavior in eight actinobacterial genera and we provide first report of 35 predatory activity in Brevibacterium, Glutamicibacter, Micromonospora, Nocardiopsis, 36Rhodococcus and Rothia. Sponge associated actinobacteria showed significantly more 37 predatory behavior than environmental isolates. While antibacterial activity by actinobacterial 38 isolates mainly affected Gram-positive target bacteria with little to no effect on Gram-negative 39 bacteria, predation targeted both Gram-positive and Gram-negative prey with equal propensity. 40 Actinobacterial isolates from both sponge and associated environment produced inhibitors of 41 serine proteases and angiotensin converting enzyme. Predatory behavior was strongly 42 associated with inhibition of trypsin and chymotrypsin. Our study suggests that sponge and 43 associated environment of western coast of India are rich in actinobacterial diversity with 44 widespread predatory activity, antibacterial activity and production of enzyme inhibitors. 45

Antimicrobial Activities of Marine Sponge-Associated Bacteria

“…The relative abundance of each phylum varies substantially where phylum Actinobacteria was the most abundant followed by Firmicutes, Proteobacteria and an insignificant amount of Bacteroidetes. In agreement with our report, a high abundance of phylum Actinobacteria has been found previously [ 32 , 68 , 69 ]. However, some studies have also reported a low level of the phylum Actinobacteria compared to Proteobacteria [ 64 , 66 , 67 , 70 ].…”

“…Many of the genera reported in this study have been described as having antimicrobial activities. In addition to Streptomyces , antimicrobial activity has also been attributed to Bacillus [ 27 , 30 , 32 , 60 , 62 , 64 , 66 , 67 , 69 , 72 ], Micrococcus [ 71 , 72 , 74 ], Microbacterium [ 73 ], Gordonia [ 72 ], Sulfitobacter [ 32 ], and Kocuria [ 35 ]. Antimicrobial activities due to Fictibacillus and Limimaricola were not reported, though phylogenetically, the genus Fictibacillus is highly related to Bacillus and Limimaricola with Sulfitobacter .…”

A Metataxonomic Approach Reveals Diversified Bacterial Communities in Antarctic Sponges

“…Similar to Proteobacteria, several studies demonstrated the great biotechnological potential of Actinobacteria, especially those belonging to the Streptomyces genus. In fact, several bioactive compounds with antimicrobial, antiviral, antiparasitic, antiprotozoal and antitumor effects have been described [ 98 , 99 , 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 ]. Moreover, genomic analyses revealed some BGCs encoding for secondary metabolites, such as PKS I and III, NRPS (nonribosomal peptides), terpene and bacteriocin gene clusters from a sponge-derived Actinobacteria showing antimicrobial activities [ 108 , 109 , 110 , 111 , 112 ].…”

Marine Actinobacteria Bioflocculant: A Storehouse of Unique Biotechnological Resources for Wastewater Treatment and Other Applications

“…Actinomycetes usually exist in mixed bacterial consortium in soil, water, marine sediments, and sponges [47,48]. For the sake of eliminating non-sporulating bacteria from samples, each sample is usually subjected to pre-heat treatment at 60 • C for 15 min.…”