A new diketopiperazine derivative from a deep sea-derived <i>Streptomyces</i> sp. SCSIO 04496

<div><p>A new diketopiperazine (DKP) derivative, (6<i>R</i>,3<i>Z</i>)-3-benzylidene-6-isobutyl-1-methyl piperazine-2,5-dione (<b>1</b>), as well as five known DKPs <b>2</b>–<b>6</b> was isolated from a deep sea-derived <i>Streptomyces</i> sp. SCSIO 04496. The structure of <b>1</b> was elucidated using a combination of 1D and 2D NMR, HR-ESI-MS and chiral-phase HPLC techniques. Compounds <b>1</b>–<b>6</b> did not show cytotoxic activity at a concentration of 100 μM in bioactivity assay.</p></div

Discovery of olimycin E from <i>Streptomyces</i> sp. 11695

A new natural product olimycin E (1), together with two known compounds of divergolide R (2) and olimycin B (3), were obtained from the marine-derived Streptomyces sp. 11695. The structures of 1–3 were established on the basis of HRESIMS as well as 1D and 2D NMR datasets. The absolute configuration of 1 is identified as 4 R, 6S, 7S, 10 R by comparison the experiment ECD with that of the theoretical ECD. Antibacterial results showed that compound 2 have antibacterial activities against Staphylococcus aureus and MRSA with the MIC values of 32 μg/mL, respectively.</p

Biosynthesis of 9‑Methylstreptimidone Involves a New Decarboxylative Step for Polyketide Terminal Diene Formation

9-Methylstreptimidone is a glutarimide antibiotic showing antiviral, antifungal, and antitumor activities. Genome scanning, bioinformatics analysis, and gene inactivation experiments reveal a gene cluster responsible for the biosynthesis of 9-methylstreptimidone in <i>Streptomyces himastatinicus</i>. The unveiled machinery features both acyltransferase- and thioesterase-less iterative use of module 5 as well as a branching module for glutarimide generation. Impressively, inactivation of <i>smdK</i> leads to a new carboxylate analogue unveiling a new mechanism for polyketide terminal diene formation

Identification of the Grincamycin Gene Cluster Unveils Divergent Roles for GcnQ in Different Hosts, Tailoring the l‑Rhodinose Moiety

The gene cluster responsible for grincamycin (GCN, <b>1</b>) biosynthesis in <i>Streptomyces lusitanus</i> SCSIO LR32 was identified; heterologous expression of the GCN cluster in <i>S. coelicolor</i> M512 yielded P-1894B (<b>1b</b>) as a predominant product. The <i>ΔgcnQ</i> mutant accumulates intermediate <b>1a</b> and two shunt products <b>2a</b> and <b>3a</b> bearing l-rhodinose for l-cinerulose A substitutions. In vitro data demonstrated that GcnQ is capable of iteratively tailoring the two l-rhodinose moieties into l-aculose moieties, supporting divergent roles of GcnQ in different hosts

Halogenated Anthraquinones from the Marine-Derived Fungus <i>Aspergillus</i> sp. SCSIO F063

Metabolomic investigations focusing on the marine-derived fungus <i>Aspergillus</i> sp. SCSIO F063 have unveiled seven new chlorinated anthraquinones (<b>1</b>–<b>7</b>) related to averantin, together with five known analogues (<b>11</b>–<b>15</b>) when the fungus was fermented using sea salt-containing potato dextrose broth. Through the addition of sodium bromide to the broth, two new brominated anthraquinones (<b>8</b>, <b>9</b>) and one new nonhalogenated anthraquinone (<b>10</b>) were obtained from the fungal mycelia. Their structures were elucidated by extensive spectroscopic analyses including MS and 1D and 2D NMR data. One metabolite, 6-<i>O</i>-methyl-7-chloroaveratin (<b>2</b>), displayed inhibition activity against three human tumor cell lines, SF-268, MCF-7, and NCI-H460, with IC₅₀ values of 7.11, 6.64, and 7.42 μM, respectively

LiCrTiO₄ Nanowires with the (111) Peak Evolution during Cycling for High-Performance Lithium Ion Battery Anodes

LiCrTiO₄ is a lithium insertion material that is isostructural with Li₄Ti₅O₁₂. Upon modification of its morphology, LiCrTiO₄ nanowires exhibit a high charge capacity of 154.6 mA h g^–1 at 100 mA g^–1, and this value can be maintained at 121.0 mA h g^–1 even at a high current density of 700 mA g^–1. Furthermore, the cycling performance shows that LiCrTiO₄ nanowires can also deliver a reversible capacity of 120.0 mA h g^–1 with 95.6% capacity retention of the first cycle after 550 cycles. The excellent electrochemical properties were revalidated by cyclic voltammetry and electrochemical impedance spectroscopy measurements. The most interesting feature in this work is the relationship between the periodic variation of the (111) peak intensities and the migration of lithium ions during cycling. This proves that LiCrTiO₄ nanowires are a zero-strain insertion material that can be a promising anode material for lithium ion batteries

Sol–Gel Synthesis and in Situ X‑ray Diffraction Study of Li₃Nd₃W₂O₁₂ as a Lithium Container

In this work, garnet-framework Li₃Nd₃W₂O₁₂ as a novel insertion-type anode material has been prepared via a facile sol–gel method and examined as a lithium container for lithium ion batteries (LIBs). Li₃Nd₃W₂O₁₂ shows a charge capacity of 225 mA h g^–1 at 50 mA g^–1, and with the current density increasing up to 500 mA g^–1, the charge capacity can still be maintained at 186 mA h g^–1. After cycling at 500 mA g^–1 for 500 cycles, Li₃Nd₃W₂O₁₂ retains about 85% of its first charge capacity changed from 190.2 to 161 mA h g^–1. Furthermore, in situ X-ray diffraction technique is adopted for the understanding of the insertion/extraction mechanism of Li₃Nd₃W₂O₁₂. The full-cell configuration LiFePO₄/Li₃Nd₃W₂O₁₂ is also assembled to evaluate the potential of Li₃Nd₃W₂O₁₂ for practical application. These results show that Li₃Nd₃W₂O₁₂ is such a promising anode material for LIBs with excellent electrochemical performance and stable structure