Mining Chromodoris quadricolor symbionts for biosynthesis of novel secondary metabolites.

Many secondary metabolites with medicinal potential are produced by various animals, plants, and microorganisms. Because marine creatures have a greater proportion of unexplored biodiversity than their terrestrial counterparts, they have emerged as a key research focus for the discovery of natural product drugs. Several studies have revealed that bacteria isolated from Chromodoris quadricolor (C. quadricolor) have antibiotic and anticancer properties. In this study, meta-transcriptomics and meta-proteimic analysis were combined to identify biosynthetic gene clusters (BGCs) in the symbiotic bacteria of the C. quadricolor mantle. Symbiotic bacteria were separated from the host by differential pelleting, and then total RNA was extracted, purified, and sequenced. Meta-transcriptomic analysis was done using different natural product mining tools to identify biosynthetic transcript clusters (BTCs). Furthermore, proteins were extracted from the same cells and then analyzed by LC-MS. A meta-proteomic analysis was performed to find proteins that are translated from BCGs. Finally, only 227 proteins have been translated from 40,742 BTCs. The majority of these clusters were polyketide synthases (PKSs) with antibacterial activity. Ten novel potential metabolic clusters with the ability to produce antibiotics have been identified in Novosphingobium and Microbacteriaceae, including members of the ribosomal synthesized and post-translationally modified peptides (RiPPs), polyketide synthases, and others. We realized that using a meta-proteomic approach to identify BGCs that have already been translated makes it easier to concentrate on BGCs that are utilized by bacteria. The symbiotic bacteria associated with C. quadricolor could be a source of novel antibiotics.

Bacterial Taxa Migrating from the Mediterranean Sea into the Red Sea Revealed a Higher Prevalence of Anti-Lessepsian Migrations.

In 1869, the Suez Canal was opened, which brought the waters of the Mediterranean and the Red Sea into direct contact. Notably, the Suez Canal was constructed for navigation purposes without focusing on the ecological impacts. The Suez Canal paved the way for species migration from the Red Sea to the Mediterranean Sea through Lessepsian migration, named after Ferdinand de Lesseps, while the migration from the Mediterranean Sea to the Red Sea is called the anti-Lessepsian migration. It has been argued in the past that the migrating species had negative consequences for the host environment as well as of humans. Few studies to date have attempted to map the microorganism migration problem because the traditional ways of measuring the community's richness and dissimilarities failed to provide enough detection of the migrating taxa. We collected 22 seawater samples from different locations in Egypt, in relationship to the migration across and to/from the Suez Canal. The V3-V4 regions of 16s genes were amplified and sequenced by the next generation Illumina MiSeq sequencer. Bioinformatics analysis revealed 15 taxa that migrated from the Mediterranean Sea to the Red Sea (i.e., anti-Lessepsian migration) such as the genera Fluvicola, HTCC2207, and Persicirhabdus. The family OCS155 is the only one that migrated from the Red Sea to the Mediterranean Sea (Lessepsian migration). Seven anti-Lessepsian migrants colonized the Suez Canal more than the Mediterranean Sea such as the genera Marinobacter and Halomonas. These findings collectively suggest that the anti-Lessepsian migration is more predominant than the Lessepsian migration in the bacterial community. This study paves the way for future research questions as well. For example, why is the anti-Lessepsian migration more common than the Lessepsian route in bacteria? Why do certain taxa stop migration at the Suez Canal, and why do certain taxa present in higher frequencies in the Suez Canal? Which taxa continue migration to the Indian Ocean and the Atlantic Ocean, and what is the impact of the anti-Lessepsian migration on the bacterial community? Understanding microbial diversity in a context of microorganism migration across seas and oceans remains a prime topic in biodiversity research and systems science.

Comparative Metagenomic Screening of Aromatic Hydrocarbon Degradation and Secondary Metabolite-Producing Genes in the Red Sea, the Suez Canal, and the Mediterranean Sea.

Marine and ecosystem pollution due to oil spills can be addressed by identifying the aromatic hydrocarbon (HC)-degrading microorganisms and their responsible genes for biodegradation. Moreover, screening for genes coding for secondary metabolites is invaluable for drug discovery. We report here, the first metagenomic study investigating the shotgun metagenome of the Suez Canal water sampled at Ismailia city concerning its aromatic HC degradation potential in comparison to the seawater sampled at Halayeb city at the Red Sea and Sallum city at the Mediterranean Sea. Moreover, for an in-depth understanding of marine biotechnology applications, we screened for the polyketide synthases (PKSs) and nonribosomal peptide synthetase (NRPS) domains in those three metagenomes. By mapping against functional protein databases, we found that 13, 6, and 3 gene classes from the SEED database; 2, 1, and 3 gene classes from the EgGNOG; and 5, 4, and 2 genes from the InterPro2GO database were identified to be differentially abundant among Halayeb, Ismailia, and Sallum metagenomes, respectively. Also, Halayeb metagenome in the Red Sea reported the highest number of PKS domains showing higher potential in secondary metabolite production in addition to the oil degradation potential.