http://www.mdpi.com/journal/marinedrugs/special_issues/marine-actinomycetes/ Dear Colleagues, Actinomycetes are filamentous Gram-positive bacteria with a complex life cycle which are widely distributed in terrestrial ecosystems, especially in soil. They are producers of a large number of natural products, many of them with clinical, pharmaceutical or agricultural application. In the last decades, marine actinomycetes are increasingly being isolated from marine environments demonstrating that actinomycetes are ubiquitous in marine sediments, but at lower numbers than in soils. Furthermore, marine actinomycetes have been found in symbiosis with different marine invertebrates, especially sponges. They have attracted great attention since they have developed unique metabolic and physiological capabilities that offer the potential to produce natural products with interesting pharmacological activities and therefore they provide a source of novel natural products with potential application in the near future. Prof. Dr. Jose A. Salas Guest Editor Submission All papers should be submitted to marinedrugs@mdpi.com with copy to the Editors. To be published continuously until the deadline and papers will be listed together at the special websites. Both, research articles and review articles are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editors for announcment on this website. Submitted papers should not have been published previously, nor be under consideration for publication elsewhere. All papers are refereed through a peer-review process. A guide for authors, sample copies and other relevant information for submitting papers are available on the Instructions for Authors page. Marine Drugs is an international peer-reviewed quarterly journal published by MDPI. Please visit the Instructions for Authors page before submitting a paper Open Access publication fees are 1000 CHF per paper. English correction fees (250 CHF) will be added in certain cases (1250 CHF per paper for those papers that require extensive additional formatting and/or English corrections.). http://www.mdpi.com/1660-3397/8/3/399/ Terrestrial actinomycetes are noteworthy producers of a multitude of antibiotics, however the marine representatives are much less studied in this regard. In this study, 90 actinomycetes were isolated from 11 different species of marine sponges that had been collected from offshore Ras Mohamed (Egypt) and from Rovinj (Croatia). Phylogenetic characterization of the isolates based on 16S rRNA gene sequencing supported their assignment to 18 different actinomycete genera representing seven different suborders. Fourteen putatively novel species were identified based on sequence similarity values below 98.2% to other strains in the NCBI database. A putative new genus related to Rubrobacter was isolated on M1 agar that had been amended with sponge extract, thus highlighting the need for innovative cultivation protocols. Testing for anti-infective activities was performed against clinically relevant, Gram-positive (Enterococcus faecalis, Staphylococcus aureus) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria, fungi (Candida albicans) and human parasites (Leishmania major, Trypanosoma brucei). Bioactivities against these pathogens were documented for 10 actinomycete isolates. These results show a high diversity of actinomycetes associated with marine sponges as well as highlight their potential to produce anti-infective agents. http://www.mdpi.com/1660-3397/8/3/399/ Fri, 26 Feb 2010 00:00:00 CET Marine Drugs 2010-02-26 8 3 Article 399 412 1660-3397 Isolation, Phylogenetic Analysis and Anti-infective Activity Screening of Marine Sponge-Associated Actinomycetes 2010-02-26 doi: 10.3390/md8030399 Usama Ramadan Abdelmohsen Sheila M. Pimentel-Elardo Amro Hanora Mona Radwan Soad H. Abou-El-Ela Safwat Ahmed Ute Hentschel http://www.mdpi.com/1660-3397/7/4/483/ Renieramycin M and jorunnamycin C, two isoquinolinequinone compounds differing only at the C-22 ester side chain, were evaluated for their cytotoxic effects on human colon (HCT116) and breast (MDA-MB-435) cancer cell lines. These two compounds displayed potent cancer cell growth inhibition, their IC50 values reaching nanomolar order. To examine their effects on transcription, we carried out oligonucleotide microarray analysis with focus on the similarities and differences between the two compounds in terms of transcriptional profiles. We found that the down-regulation of PTPRK (protein tyrosine phosphatase receptor type K) can be considered as a biomarker responsive to the cytotoxic effects of this class of antitumor marine natural products. http://www.mdpi.com/1660-3397/7/4/483/ Mon, 19 Oct 2009 00:00:00 CEST Marine Drugs 2009-10-19 7 4 Communication 483 494 1660-3397 Microarray-Based Transcriptional Profiling of Renieramycin M and Jorunnamycin C, Isolated from Thai Marine Organisms 2009-10-19 doi: 10.3390/md7040483 Kornvika Charupant Khanit Suwanborirux Naomi Daikuhara Masashi Yokoya Rie Ushijima-Sugano Takatoshi Kawai Takashi Owa Naoki Saito