Discovery, isolation, and characterization of diazeniumdiolate siderophores.

The C-diazeniumdiolate (N-nitrosohydroxylamine) group in the amino acid graminine (Gra) is a newly discovered Fe(III) ligand in microbial siderophores. Graminine was first identified in the siderophore gramibactin, and since this discovery, other Gra-containing siderophores have been identified, including megapolibactins, plantaribactin, gladiobactin, trinickiabactin (gramibactin B), and tistrellabactins. The C-diazeniumdiolate is photoreactive in UV light which provides a convenient characterization tool for this type of siderophore.

pH-Tolerant Wet Adhesion of Catechol Analogs.

The need for improved wet adhesives has driven research on mussel-inspired materials incorporating dihydroxyphenylalanine (DOPA) and related analogs of the parent catechol, but their susceptibility to oxidation limits practical application of these functionalities. Here, we investigate the molecular-level adhesion of the catechol analogs dihydroxybenzamide (DHB) and hydroxypyridinone (HOPO) as a function of pH. We find that the molecular structure of the catechol analogs influences their susceptibility to oxidation in alkaline conditions, with HOPO emerging as a particularly promising candidate for pH-tolerant adhesives for diverse environmental conditions.

Tistrellabactins A and B Are Photoreactive -Diazeniumdiolate Siderophores from the Marine-Derived Strain KA081020-065.

The -diazeniumdiolate group in the amino acid graminine is emerging as a new microbially produced Fe(III) coordinating ligand in siderophores, which is photoreactive. While the few siderophores reported from this class have only been isolated from soil-associated microbes, here we report the first -diazeniumdiolate siderophores tistrellabactins A and B, isolated from the bioactive marine-derived strain KA081020-065. The structural characterization of the tistrellabactins reveals unique biosynthetic features including an NRPS module iteratively loading glutamine residues and a promiscuous adenylation domain yielding either tistrellabactin A with an asparagine residue or tistrellabactin B with an aspartic acid residue at analogous positions.

Perceptions of pediatric deceased donor consent: A survey of organ procurement organizations.

Background: Children awaiting transplantation face a high risk of waitlist mortality due to a shortage of pediatric organ donors. Pediatric donation consent rates vary across Organ Procurement Organizations (OPOs), suggesting that some OPOs might utilize more effective pediatric-focused donor recruitment techniques than others. An online survey of 193 donation requestor staff sheds light on the strategies that OPO staff utilize when approaching potential pediatric deceased organ donors.

The impact of donor consent mechanism on organ procurement organization performance in the United States.

Background: Lack of donor organ availability represents a major limitation to the success of solid organ transplantation. The Scientific Registry of Transplant Recipients (SRTR) publishes performance reports of organ procurement organizations (OPO) in the United States, but does not stratify by the mechanism of donor consent, namely first-person authorization (organ donor registry) and next-of-kin authorization. This study aimed to report the trends in deceased organ donation in the United States and assess the regional differences in OPO performance after accounting for the different mechanisms of donor consent.

Mining elements of siderophore chirality encoded in microbial genomes.

The vast majority of bacteria require iron to grow. A significant iron acquisition strategy is the production of siderophores, which are secondary microbial metabolites synthesized to sequester iron(III). Siderophore structures encompass a variety of forms, of which highly modified peptidic siderophores are of interest herein.

-Diazeniumdiolate Graminine in the Siderophore Gramibactin Is Photoreactive and Originates from Arginine.

Siderophores are synthesized by microbes to facilitate iron acquisition required for growth. Catecholate, hydroxamate, and α-hydroxycarboxylate groups comprise well-established ligands coordinating Fe(III) in siderophores. Recently, a -type diazeniumdiolate ligand in the newly identified amino acid graminine (Gra) was found in the siderophore gramibactin (Gbt) produced by DSM 17151.

On the origin of amphi-enterobactin fragments produced by Vibrio campbellii species.

Amphi-enterobactin is an amphiphilic siderophore isolated from a variety of microbial Vibrio species. Like enterobactin, amphi-enterobactin is a triscatecholate siderophore; however, it is framed on an expanded tetralactone core comprised of four L-Ser residues, of which one L-Ser is appended by a fatty acid and the remaining L-Ser residues are appended by 2,3-dihydroxybenzoate (DHB). Fragments of amphi-enterobactin composed of 2-Ser-1-DHB-FA and 3-Ser-2-DHB-FA have been identified in the supernatant of Vibrio campbellii species.

Ruckerbactin Produced by YRB Is a Diastereomer of the Siderophore Trivanchrobactin Produced by DS40M4.

The Gram-negative bacterium is the causative agent for enteric red mouth disease in salmonids. The genome of YRB contains a biosynthetic gene cluster encoding the biosynthesis of catechol siderophores that are diastereomeric with the known vanchrobactin class of siderophores, (DHBArgSer). Ruckerbactin (), produced by YRB, was found to be the linear tris-l-serine ester composed of l-arginine and 2,3-dihydroxybenzoic acid, (DHBArgSer).

Don't Throw Your Heart Away: Increased Transparency of Donor Utilization Practices in Transplant Center Report Cards Alters How Center Performance Is Evaluated.

Background: Publicly available report cards for transplant centers emphasize posttransplant survival and obscure the fact that some centers reject many of the donor organs they are offered (reflecting a conservative donor acceptance strategy), while others accept a broader range of donor offers (reflecting an open donor acceptance strategy).

Objective: We assessed how the provision of salient information about donor acceptance practices and waitlist survival rates affected evaluation judgments of hospital report cards given by laypeople and medical trainees.

Methods: We tested 5 different report card formats across 4 online randomized experiments (1 = 1,003, 2 = 105, 3 = 123, 4 = 807) in the same hypothetical decision.

Genomics-driven discovery of chiral triscatechol siderophores with enantiomeric Fe(iii) coordination.

Ferric complexes of triscatechol siderophores may assume one of two enantiomeric configurations at the iron site. Chirality is known to be important in the iron uptake process, however an understanding of the molecular features directing stereospecific coordination remains ambiguous. Synthesis of the full suite of (DHBLysSer) macrolactone diastereomers, which includes the siderophore cyclic trichrysobactin (CTC), enables the effects that the chirality of Lys and Ser residues exert on the configuration of the Fe(iii) complex to be defined.

Photoactive siderophores: Structure, function and biology.

It is well known that bacteria and fungi have evolved sophisticated systems for acquiring the abundant but biologically inaccessible trace element iron. These systems are based on high affinity Fe(III)-specific binding compounds called siderophores which function to acquire, transport, and process this essential metal ion. Many hundreds of siderophores are now known and their numbers continue to grow.

Predictors of Deceased Organ Donation in the Pediatric Population.

Background: A shortage of donor organs represents the major barrier to the success of solid organ transplantation. This is especially true in the pediatric population for which the number of organ donors has decreased over time. With this study, we aimed to assess the factors associated with deceased organ donor consent in the pediatric population and determine the variability in consent rates across organ procurement organizations (OPOs).

Precursor-directed biosynthesis of catechol compounds in DSM 14964.

Genome mining for VibH homologs reveals several species of Acinetobacter with a gene cluster that putatively encodes the biosynthesis of catechol siderophores with an amine core. A. bouvetii DSM 14964 produces three novel biscatechol siderophores: propanochelin (1), butanochelin (2), and pentanochelin (3).

ISHLT consensus statement on donor organ acceptability and management in pediatric heart transplantation.

The number of potential pediatric heart transplant recipients continues to exceed the number of donors, and consequently the waitlist mortality remains significant. Despite this, around 40% of all donated organs are not used and are discarded. This document (62 authors from 53 institutions in 17 countries) evaluates factors responsible for discarding donor hearts and makes recommendations regarding donor heart acceptance.

Behavioral economics-A framework for donor organ decision-making in pediatric heart transplantation.

The high discard rate of pediatric donor hearts presents a major challenge for children awaiting heart transplantation. Recent literature identifies several factors that contribute to the disparities in pediatric donor heart usage, including regulatory oversight, the absence of guidelines on pediatric donor heart acceptance, and variation among transplant programs. However, a likely additional contributor to this issue are the behavioral factors influencing transplant team decisions in donor offer scenarios, a topic that has not yet been studied in detail.

Impact of Molecular Architecture and Adsorption Density on Adhesion of Mussel-Inspired Surface Primers with Catechol-Cation Synergy.

Marine mussels secrete proteins rich in residues containing catechols and cationic amines that displace hydration layers and adhere to charged surfaces under water via a cooperative binding effect known as catechol-cation synergy. Mussel-inspired adhesives containing paired catechol and cationic functionalities are a promising class of materials for biomedical applications, but few studies address the molecular adhesion mechanism(s) of these materials. To determine whether intramolecular adjacency of these functionalities is necessary for robust adhesion, a suite of siderophore analog surface primers was synthesized with systematic variations in intramolecular spacing between catechol and cationic functionalities.

Patients and their family members prioritize post-transplant survival over waitlist survival when considering donor hearts for transplantation.

Heart transplant providers often focus on post-transplant outcomes when making donor decisions, potentially at the expense of higher waitlist mortality. This study aimed to assess public opinion regarding the selection of donor hearts and the balance between pre- and post-transplant risk. The authors generated a survey to investigate public opinion regarding donor acceptance.

Genomic analysis of siderophore β-hydroxylases reveals divergent stereocontrol and expands the condensation domain family.

Genome mining of biosynthetic pathways streamlines discovery of secondary metabolites but can leave ambiguities in the predicted structures, which must be rectified experimentally. Through coupling the reactivity predicted by biosynthetic gene clusters with verified structures, the origin of the β-hydroxyaspartic acid diastereomers in siderophores is reported herein. Two functional subtypes of nonheme Fe(II)/α-ketoglutarate-dependent aspartyl β-hydroxylases are identified in siderophore biosynthetic gene clusters, which differ in genomic organization-existing either as fused domains (IβH) at the carboxyl terminus of a nonribosomal peptide synthetase (NRPS) or as stand-alone enzymes (TβH)-and each directs opposite stereoselectivity of Asp β-hydroxylation.

A suite of asymmetric citrate siderophores isolated from a marine Shewanella species.

Woodybactins A-D are a suite of new fatty acyl siderophores produced by the luminous marine bacterium Shewanella woodyi MS32. While this bacterium has a set of genes homologous to the biosynthetic gene cluster for aerobactin, aerobactin is not produced. The arrangement of these genes within the genome differs in S.

Ambiguity of NRPS Structure Predictions: Four Bidentate Chelating Groups in the Siderophore Pacifibactin.

Identified through a bioinformatics approach, a nonribosomal peptide synthetase gene cluster in Alcanivorax pacificus encodes the biosynthesis of the new siderophore pacifibactin. The structure of pacifibactin differs markedly from the bioinformatic prediction and contains four bidentate metal chelation sites, atypical for siderophores. Genome mining and structural characterization of pacifibactin is reported herein, as well as characterization of pacifibactin variants accessible due to a lack of adenylation domain fidelity during biosynthesis.

Correction to: Amphi‑enterobactin commonly produced among Vibrio campbellii and Vibrio harveyi strains can be taken up by a novel outer membrane protein FapA that also can transport canonical Fe(III)‑enterobactin.

In the original publication, third author's name was incorrectly published as Aneta L. Jelowicki.

Amphi-enterobactin commonly produced among Vibrio campbellii and Vibrio harveyi strains can be taken up by a novel outer membrane protein FapA that also can transport canonical Fe(III)-enterobactin.

Vibrio campbellii BAA-1116 (formerly Vibrio harveyi) is a model organism for quorum sensing study and produces the siderophores anguibactin and amphi-enterobactin. This study examined the mechanisms and specificity of siderophore uptake in V. campbellii and V.