Discovery of the Lipopeptides Albubactins A-H from RKJM0023 via Chemical Elicitation with Rhamnolipids and Synthesis of Albubactin A.

The marine tunicate-derived RKJM0023 was cultured in the presence of a rhamnolipid mixture in an effort to elicit the production of silent natural products. MS/MS-based molecular networking analysis enhanced with nonparametric statistics highlighted the upregulation of a molecular cluster (Kruskal-Wallis = 1.6 e for ) in which no MS/MS features had library matches.

Discovery of Acyl-Surugamide A2 from Marine RKJM-0023-A New Cyclic Nonribosomal Peptide Containing an N-ε-acetyl-L-lysine Residue.

We report the discovery of a novel cyclic nonribosomal peptide (NRP), acyl-surugamide A2, from a marine-derived RKJM-0023 (CP133227). The structure of acyl-surugamide A2 was elucidated using a combination of NMR spectroscopy, MS2 fragmentation analysis, and comparative analysis of the biosynthetic gene cluster. Acyl-surugamide A2 contains all eight core amino acids of surugamide A, with a modified N-ε-acetyl-L-lysine residue.

Mechanism of action of pseudopteroxazole and pseudopterosin G: Diterpenes from marine origin.

Pseudopteroxazole (Ptx) and the pseudopterosins are marine natural products with promising antibacterial potential. While Ptx has attracted interest for its antimycobacterial activity, pseudopterosins are active against several clinically relevant pathogens. Both compound classes exhibit low cytotoxicity and accessibility to targeted synthesis, yet their antibacterial mechanisms remain elusive.

Caryophyllene Sesquiterpenes from a Endophyte of the Canadian Medicinal Plant .

Punctaporonins T () and U (), new caryophyllene sesquiterpenes, were isolated with three known punctaporonins, A (), B (), and C (), from the endophytic fungus (TC2-041). The structures and relative configurations of punctaporonins T and U were elucidated based on a combination of HRESIMS, 1D/2D NMR spectroscopic analysis, and X-ray diffraction analysis, while their absolute configuration is presumed to be consistent with the co-isolated - on biogenetic arguments. Compound showed weak inhibitory activity against both and .

Discovery of Levesquamide B through Global Natural Product Social Molecular Networking.

Levesquamide A is an isothiazolinone-containing anti-tubercular natural product isolated from sp. RKND-216. Through the use of Global Natural Product Social Molecular Networking (GNPS), additional members of the levesquamide family were identified (B-G).

Microfabrication of a micron-scale microbial-domestication pod for cultivation of marine bacteria.

Through the hyphenation of microfabrication, microfluidics and microbiology, we report the development of a μMicrobial-Domestication Pod (μMD Pod). This cultivation device facilitates cell signaling from neighbouring species and interactions with environmental stimuli for marine bacterial growth to overcome current barriers faced by standard laboratory cultivation methods.

Draft Genome Sequence of sp. Strain RKCA744, Isolated from the Arauca River, Colombia.

sp. strain RKCA744 was isolated from sediment collected from the Arauca River, Colombia.

Draft Genome Sequences of Three Streptomycetes Isolated from Frobisher Bay Marine Sediments.

Three strains (RKAG290, RKAG293, and RKAG337) were isolated from intertidal marine sediments of Frobisher Bay (Canada).

Microencapsulation and incubation methodology for the cultivation of marine bacteria.

Environmental microorganisms are important sources of biotechnology innovations; however, the discovery process is hampered by the inability to culture the overwhelming majority of microbes. To drive the discovery of new biotechnology products from previously unculturable microbes, several methods such as modification of media composition, incubation conditions, single-cell isolation, and incubation, have been employed to improve microbial recovery from environmental samples. To improve microbial recovery, we examined the effect of microencapsulation followed by incubation on the abundance, viability, and diversity of bacteria recovered from marine sediment.

sp. nov. isolated from the sea sponge .

A Gram-negative, motile, rod-shaped marine bacterium, designated RKSG542, was isolated from the sea sponge collected at a depth of 20 m off the west coast of San Salvador, The Bahamas. Phylogenetic analyses based on 16S rRNA gene and genome sequences place RKSG542 in a monophyletic clade with members of the genus . Strain RKSG542 shared <96.

Effects of Matrix Composition and Temperature on Viability and Metabolic Activity of Microencapsulated Marine Bacteria.

To enhance the discovery of novel natural products, various innovations have been developed to aid in the cultivation of previously unculturable microbial species. One approach involving the microencapsulation of bacteria has been gaining popularity as a new cultivation technique, with promising applications. Previous studies demonstrated the success of bacterial encapsulation; however, they highlighted that a key limitation of encapsulating bacteria within agarose is the high temperature required for encapsulation.

Boron-containing capsaicinoids.

This study reports on the preparation of eight new boron-containing capsaicinoids bearing long aliphatic chains, as an expansion of our previous studies to include tertiary amide derivatives into our substrate scope. Our boron-moiety, a pinacolboronate ester (Bpin) fragment, has been incorporated in two locations: as an aryl substituent of the capsaicinoid produced by the reductive amination of veratraldehyde, or at the terminal end of an aliphatic substituent using an iridium catalyzed hydroboration reaction. We report that most compounds in our series show moderate antimicrobial and cytotoxic activity, surpassing activities noted in our previous study.

Synthesis of ()()-Tiruchanduramine.

The absolute stereochemistry of the marine alkaloid ()-()-tiruchanduramine was established via a convergent total synthesis in six steps and 15.5% overall yield from Fmoc-D-Dab(Boc)-OH.

Complete Genome Sequence of Phage ϕRKBJ001 Isolated from Prince Edward Island, Canada.

We reported here the complete genome sequence of phage ϕRKBJ001 that was isolated from a saltwater marsh on Prince Edward Island, Canada, using the sp. strain RKBHB0173. Based on electron microscopy and genomic analysis, this phage belongs to the family and the BN phage cluster.

Development of N,O-Carboxymethyl Chitosan-Starch Biomaterial Inks for 3D Printed Wound Dressing Applications.

In this paper, a novel hybrid biomaterial ink consisting of two water-soluble polymers is investigated: starch and N,O-carboxymethyl chitosan (NOCC). The biomaterial ink is used to fabricate controlled release biodegradable wound dressing scaffolds via a novel low-temperature solvent (organic)-free 3D printing technique. NOCC is a variant of chitosan with a high degradation rate that can lead to an immediate release of the drugs, and starch, on the other hand, is used to alter degradation and drug release characteristics of the biomaterial.

gen. nov., sp. nov., a marine bacterium isolated from the sea sponge .

A Gram-stain-negative, strictly aerobic, motile bacterium, designated strain RKSG073, was isolated from the sea sponge , collected off the west coast of San Salvador, The Bahamas. Cells were curved-to-spiral rods with single, bipolar (amphitrichous) flagella, oxidase- and catalase-positive, non-nitrate-reducing and required salt for growth. RKSG073 grew optimally at 30-37 °C, pH 6-7, and with 2-3 % (w/v) NaCl.

Auyuittuqamides A-D, Cyclic Decapeptides from RKAG 186 Isolated from Frobisher Bay Sediment.

Four new cyclic decapeptides, auyuittuqamides A-D (-), were obtained from RKAG 186 obtained from marine sediment collected from the intertidal zone of Frobisher Bay, Nunavut, Canada. The structures of the compounds were elucidated by NMR spectroscopy and tandem mass spectrometry. The absolute configurations of the amino acids were determined using Marfey's method.

Comparative Microbiome and Metabolome Analyses of the Marine Tunicate from Native and Invaded Habitats.

Massive fouling by the invasive ascidian in Prince Edward Island (PEI, Canada) has been causing devastating losses to the local blue mussel farms. In order to gain first insights into so far unexplored factors that may contribute to the invasiveness of in PEI, we undertook comparative microbiome and metabolome studies on specific tissues from populations collected in invaded (PEI) and native regions (Helgoland and Kiel, Germany). Microbial community analyses and untargeted metabolomics revealed clear location- and tissue-specific patterns showing that biogeography and the sampled tissue shape the microbiome and metabolome of .

Development of a microbe domestication pod (MD Pod) for in situ cultivation of micro-encapsulated marine bacteria.

Microbial marine natural products hold significant potential for the discovery of new bioactive therapeutics such as antibiotics. Unfortunately, this discovery is hindered by the inability to culture the majority of microbes using traditional laboratory approaches. While many new methods have been developed to increase cultivability, a high-throughput in situ incubation chamber capable of simultaneously isolating individual microbes while allowing cellular communication has not previously been reported.

Development of 3D Printed Drug-Eluting Scaffolds for Preventing Piercing Infection.

Herein, novel drug-eluting, bio-absorbable scaffold intended to cover piercing studs is introduced. This "biopierce" will stay in human tissue following piercing, and will slowly release an antimicrobial agent to prevent infection while the wound heals. Nearly 20% of all piercings lead to local infection.

Metabolomic Comparison and Assessment of Co-cultivation and a Heat-Killed Inducer Strategy in Activation of Cryptic Biosynthetic Pathways.

Co-cultivation has been used as a promising tool to turn on or up-regulate cryptic biosynthetic pathways for microbial natural product discovery. Recently, a modified culturing strategy similar to co-cultivation was investigated, where heat-killed inducer cultures were supplemented to the culture medium of producer fermentations to induce cryptic pathways. In the present study, the repeatability and effectiveness of both methods in turning on cryptic biosynthetic pathways were unbiasedly assessed using UHPLC-HRESIMS-based metabolomics analysis.

Guanahanolide A, a Meroterpenoid with a Sesterterpene Skeleton from Coral-Derived sp.

A meroterpenoid, guanahanolide A (), was purified from a fermentation extract of sp. RKBH-B7. The planar structure of guanahanolide A () was elucidated by NMR spectroscopy, revealing a meroterpenoid comprised of an unprecedented sesterterpene skeleton.

Pseudopterosin and -Methyltylophorinidine Suppress Cell Growth in a 3D Spheroid Co-Culture Model of Pancreatic Ductal Adenocarcinoma.

Current therapies for treating pancreatic ductal adenocarcinoma (PDAC) are largely ineffective, with the desmoplastic environment established within these tumors being considered a central issue. We established a 3D spheroid co-culture in vitro model using a PDAC cell line (either PANC-1 or Capan-2), combined with stellate cells freshly isolated from pancreatic tumors (PSC) or hepatic lesions (HSC), and human type I collagen to analyze the efficiency of the chemotherapeutic gemcitabine (GEM) as well as two novel drug candidates derived from natural products: pseudopterosin (PsA-D) and -methyltylophorinidine (TYLO). Traditional 2D in vitro testing of these agents for cytotoxicity on PANC-1 demonstrated IC values of 4.

Discovery of an Isothiazolinone-Containing Antitubercular Natural Product Levesquamide.

Antitubercular agent levesquamide is a new polyketide-nonribosomal peptide (PK-NRP) hybrid marine natural product isolated from sp. RKND-216. The structure contains a rare isothiazolinone moiety which has only been reported in collismycin SN.

sp. nov. and gen. nov., sp. nov., marine bacteria isolated from the sponge , and emended description of the genus .

Two Gram-stain-negative, strictly aerobic, marine bacteria, designated as strains RKSG066 and RKSG123, were isolated from a sponge collected at a depth of 15 m off the west coast of San Salvador, The Bahamas. Investigation of nearly full-length 16S rRNA gene and whole genome-based phylogenies revealed that both strains belong to the order within the class and phylum . Strain RKSG066 formed a monophyletic clade with described members of the genus , while strain RKSG123 formed a well-supported paraphyletic branch apart from this and other related genera within the family .