Genes mcr improve the intestinal fitness of pathogenic E. coli and balance their lifestyle to commensalism.

Background: The plasmid-mediated resistance gene mcr-1 confers colistin resistance in Escherichia coli and paves the way for the evolution to pan-drug resistance. We investigated the impact of mcr-1 in gut colonization in the absence of antibiotics using isogenic E. coli strains transformed with a plasmid encoding or devoid of mcr-1.

Synthesis and In Vitro Comparison of DOTA, NODAGA and 15-5 Macrocycles as Chelators for the Cu-Labelling of Immunoconjugates.

The development of Cu-based immuno-PET radiotracers requires the use of copper-specific bifunctional chelators (BFCs) that contain functional groups allowing both convenient bioconjugation and stable copper complexes to limit in vivo bioreduction, transmetallation and/or transchelation. The excellent in vivo kinetic inertness of the pentaazamacrocyclic [Cu]Cu-15-5 complex prompted us to investigate its potential for the Cu-labelling of monoclonal antibodies (mAbs), compared with the well-known NODAGA and DOTA chelators. To this end, three NODAGA, DOTA and 15-5-derived BFCs, containing a pendant azadibenzocyclooctyne moiety, were synthesised and a robust methodology was determined to form covalent bonds between them and azide-functionalised trastuzumab, an anti-HER2 mAb, using strain-promoted azide-alkyne cycloaddition.

Design, synthesis and evaluation of targeted hypoxia-activated prodrugs applied to chondrosarcoma chemotherapy.

The tumor microenvironment in chondrosarcoma (CHS), a chemo- and radio-resistant cancer provides unique hallmarks for developing a chondrosarcoma targeted drug-delivery system. Tumor targeting could be achieved using a quaternary ammonium function (QA) as a ligand for aggrecan, the main high negative charged proteoglycan of the extracellular matrix of CHS, and a 2-nitroimidazole as trigger that enables hypoxia-responsive drug release. In a previous work, ICF05016 was identified as efficient proteoglycan-targeting hypoxia-activated prodrug in a human extraskeletal myxoid chondrosarcoma model in mice and a first study of the structure-activity relationship of the QA function and the alkyl linker length was conducted.

Proteoglycans as Target for an Innovative Therapeutic Approach in Chondrosarcoma: Preclinical Proof of Concept.

To date, surgery remains the only option for the treatment of chondrosarcoma, which is radio- and chemoresistant due in part to its large extracellular matrix (ECM) and poor vascularity. In case of unresectable locally advanced or metastatic diseases with a poor prognosis, improving the management of chondrosarcoma still remains a challenge. Our team developed an attractive approach of improvement of the therapeutic index of chemotherapy by targeting proteoglycan (PG)-rich tissues using a quaternary ammonium (QA) function conjugated to melphalan (Mel).

Development of a freeze-dried kit formulation for the preparation of 99mTc-NTP 15-5, a radiotracer for scintigraphic imaging of proteoglycans.

The cartilage-targeting strategy is based on the strong affinity of quaternary ammonium (QA) functions for cartilage proteoglycans. We use a bifunctional agent containing QA moiety and a polyazamacrocycle structure able to complex technetium-99m. (99m)Tc-NTP 15-5 was selected for its high stability and its high affinity for proteoglycans in vivo.

Synthesis, crystal structure, characterisation, and antifungal activity of 3-thiophene aldehyde semicarbazone (3STCH), 2,3-thiophene dicarboxaldehyde bis(semicarbazone) (2,3BSTCH2) and their nickel (II) complexes.

The reaction of nickel (II) chloride and bromide with 3-thiophene aldehyde semicarbazone (3STCH) and 2,3-thiophene dicarboxaldehyde bis(semicarbazone) (2,3BSTCH(2)) leads to the formation of a series of new complexes: [NiCl(2)(3STCH)(2)], [NiBr(2)(3STCH)(2)], [NiCl(2,3BSTCH(2))(H(2)O)]Cl, and [NiBr(2,3BSTCH(2))(H(2)O)]Br respectively. The crystal structures of the two ligands 3STCH, 2,3BSTCH(2) and of the complex [NiBr(2,3BSTCH(2))(H(2)O)]Br have been determined by X-ray diffraction methods. For all these complexes, the central ion is coordinated through the oxygen atom of the carbonyle and the azomethine nitrogen atom of the semicarbazone.

Selective C-acylation of 2-aminoimidazo[1,2-a]pyridine: application to the synthesis of imidazopyridine-fused [1,3]diazepinones.

A series of 20 optically pure 3,4-dihydro-5H-pyrido[1',2':1,2]imidazo[4,5-d][1,3]diazepin-5-ones which form a new family of azaheterocycle-fused [1,3]diazepines were synthesized in four steps with 17-66% overall yields. The key step consists of a selective C-acylation reaction of easily accessible 2-aminoimidazo[1,2-a]pyridine at C-3.

Synthesis and antiviral activity of an imidazo[1,2-a]pyrrolo[2,3-c]pyridine series against the bovine viral diarrhea virus.

A series of imidazo[1,2-a]pyrrolo[2,3-c]pyridines has been prepared and evaluated for their anti-BVDV activities in MDBK cells. From the synthesized analogues bearing modifications of the substituents at positions 2, 3, 7 and 8, compounds 10a, b, 16, 24, 25 and 26 exhibited significant anti-BVDV activities.

New opportunities with the Duff reaction.

The Duff reaction (HMTA, AcOH or TFA) was studied on substituted [6 + 5] heterocyclic compounds. This reaction provides a useful route to aldehydes for compounds bearing sensitive amide functions. It gives also access to tricyclic lactams of potential biological interest.

(2R,3S)-2-Ammonio-3-hydr-oxy-3-(4-nitro-phen-yl)propanoic acid chloride monohydrate.

The title compound, C(9)H(11)N(2)O(5) (+)·Cl(-)·H(2)O, was synthesized from (1S,2S)-2-amino-1-(4-nitro-phen-yl)propane-1,3-diol in four steps. As demonstrated by this work, no racemization occurs during this synthetic procedure. The crystal structure displays many inter-molecular hydrogen bonds between the acidic cation, chloride anions and the water mol-ecules, forming a three-dimensional network.