In the last decade, along with the development of taxonomy research in marine-derived actinobacteria, more and more halogenated natural products were discovered from marine actinobacteria. Most of them showed good biological activity and unique structure compared to those from land. The special halogenation mechanism in some compounds' biosynthesis has drawn great attention. So in this review, we focus on the halogenated natural products from marine actinobacteria and their halogenation mechanisms.

Objective To study the Diagnosis and treatment of thyroglossal duct cyst or fistula. Methods The clinical data of 67 patients with thyroglossal duct cyst or fistula treated by surgery were analyzed retrospectively. Results The diagnosis rate preoperatively was 92.5% and the accuracy diagnosis rate by B type ultrasonography was 96.1%; all cases were treated by operation, of them, 14 cases underwent simple cyst resection, 12 with resection of partial periosteum of hyoid and 41 with resection of middle segment of hyoid( Sistrunk's operation ). 54 cases were followed up, recurrence in cases with cyst was 4 of 43 (9.3%) and recurrence in cases with fistula was 2 of 11(18.2%)respectively. Conclusion Ultrasonography shows certain characteristics and clinical value to diagnose and distinguish thyroglossal duct cyst. Postoperative recurrence is due to the selection of operation procedures and control of infection of focus. The Sistrunk's operation properly performed previou to cyst infection should reduce recurrence rate markedly.

The crude extracts of the fermentation broth from a marine sediment-derived actinomycete strain, Saccharothrix sp. 10-10, showed significant antibacterial activities against drug-resistant pathogens. A genome-mining PCR-based experiment targeting the genes encoding key enzymes involved in the biosynthesis of secondary metabolites indicated that the strain 10-10 showed the potential to produce tetracenomycin-like compounds. Further chemical investigation of the cultures of this strain led to the identification of two antibiotics, including a tetracenomycin (Tcm) analogs, Tcm X (1), and a tomaymycin derivative, oxotomaymycin (2). Their structures were identified by spectroscopic data analysis, including UV, 1D-NMR, 2D-NMR and MS spectra. Tcm X (1) showed moderate antibacterial activities against a number of drug-resistant pathogens, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE) pathogens, with the MIC values in the range of 32-64 microg x mL(-1). In addition, 1 also displayed significant cytotoxic activities against human cancer cell lines, including HL60 (leukemia), HepG2 (liver), and MCF-7 (breast) with the IC 50 values of 5.1, 9.7 and 18.0 micromol x L(-1), respectively. Guided by the PCR-based gene sequence analysis, Tcm X (1) and oxotomaymycin (2) were identified from the genus of Saccharothrix and their 13C NMR data were correctly assigned on the basis of 2D NMR spectroscopic data analysis for the first time.