Autophagy is a process of removal and degradation of unneeded or damaged cellular components, which plays an essential role in several physiological processes and associated diseases or ageing. Despite its importance, a simply applicable selective fluorescent dye able to specifically stain autolysosomes as a particular component of autophagy does not exist. Addressing this challenge, we present a new BODIPY-aza-indole complex (BODIPY-AZD-1) as a fluorescent dye selectively staining autolysosomes and distinguish them from lysosomes and autophagosomes. Taking advantage of BODIPY, this compound has excellent fluorescent properties, it is resistant to photobleaching, it is not phototoxic, and it is compatible with live-cell, time-lapse, and super-resolution microscopy and fixation. Due to the simple staining procedure and non-toxicity, we suggest this compound for studies of later phases of autophagy as well as for observation of autolysosome physiology in live and/or fixed cells.

We present the application of a Glaser-Hay diyne coupling for the synthesis of conformationally constrained Nα-amino acid amides with different diyne ring sizes. Twelve-membered rings were the smallest rings that could be prepared by this approach. We observed the formation of triethylammonium adducts in the cases of smaller (10- and 11-membered) rings. Calculation of the conformational barriers for the cyclization reactions of various ring sizes demonstrated that the formation of amino acid-derived smaller rings by this reaction is thermodynamically unfavorable.

The reactions of hydrazones, derived from various aromatic aldehydes bound to Rink resin and hydrazines, with trimethylsilanolate have been studied. In this process, the aldehydes were oxidized to the corresponding carboxylic acids. The reaction was also tested with success in solution, with various aromatic aldehydes easily being oxidized in one pot via hydrazone formation and trimethylsilanolate treatment. A mechanism for the hydrazone cleavage is proposed. The reaction may be used as an alternative method for aldehyde oxidation with the selectivity complementary to that of currently used reactions.

One-step replacement of NH2 groups in ring-substituted anilines by deuterium is reported. Approaches comprising both solid-phase and solution-phase syntheses can be used on a large variety of substrates. The method uses diazotization in a mixture of water and either dichloromethane or chloroform, which serve as a source of hydrogen. This protocol can be used as a general method for fast and easy incorporation of deuterium into an aromatic system using deuterated chloroform.

The use of a hydrazine derived from a backbone amide linker as a new hydrazone-based traceless linker for solid-phase organic synthesis is described. The stability of the linker was tested under various conditions, including treatment with acids, bases, and borohydrides. Final compounds can be released by selective cleavage using trimethylsilanolate. To demonstrate the versatility of the linker, the synthesis of a model compound under various reaction conditions was performed with good results.

The increasing prevalence of antibiotic‐resistant bacterial strains has necessitated the synthesis of novel antibacterial agents. It was previously shown that naturally occurring metalloporphyrin hemin possesses dark antibacterial activity against Gram‐positive bacteria. To improve hemin antibacterial activity, we synthesized a number of hemin conjugates with amino acids and branched peptides. Arginine‐containing hemin conjugates demonstrated high antibacterial activity against Gram‐positive bacteria including methicillin‐ and vancomycin‐resistant strains in vitro . Most of the synthesized conjugates showed low toxicity against human erythrocytes and leukocytes.

We synthesized a series of hemin derivatives (HDs) substituted by residues of amino acids and peptides at either one or two propionic-acid residues, and studied the virucidal activity of the compounds obtained against herpes simplex virus. Compounds 6,7-bis-(methyl ester N 0 L-seryl)-protohemin (IX) (2) and 6,7-bis-[methyl ester N 0 -L-arginyl)-protohemin (IX) (6) shown the highest virucidal activity. We also investigated the interaction between HDs and lipid-membrane components as a possible mechanism of virucidal action. A model system including Clark's electrode and a micellar solution of methyl linoleate was used to quantitatively assess the capability of HDs to catalyze the oxidation of polyunsaturated fatty acids as components of lipid membranes. Another model system including liposomes that consisted of dioleoylphosphatydylcholine and was loaded with the fluorescent dye carboxyfluorescein was employed to examine the effect of HDs on lipid-membrane permeability. The kinetics and efficacy of increasing liposome-membrane permeability on exposure to HDs appeared to depend on the nature of the substituents in the HDs. The findings are strongly suggestive of the presence of two different modes of interaction between an HD and the lipid membrane, i.e. oxidative and non-oxidative mechanisms possibly underlie the virucidal action of HDs.

Due to a steadily increasing number of clinical isolates of microscopic fungi that show resistance to conventionally administered antimycotics, the specialists involved have constantly been searching for novel fungicidal agents among various classes of chemical compounds. The present study was aimed at synthesizing and assessing the activity of arginine-containing hemin derivatives against strains of Candida albicans and Cryptococcus neoformans insensitive to commonly used antifungal agents. A hemin conjugate with a branched arginine-containing peptide was shown to exhibit in vitro fungicidal activity at a concentration of 25 μM and inhibit the growth of the yeast-like fungus Candida albicans at concentrations as low as 12.5 μM.

This review deals with antimicrobial peptides (AMPs) that demonstrate antibacterial, antiviral, and antifungal activity. It considers structure and mechanism of AMP interaction with lipid membrane and intracellular targets of pathogens. Special attention is paid to modern state and perspectives of AMP practical application and also to approaches that increase efficacy and reduce toxicity of AMP by chemical modification of their structure.

Arginine-containing peptides consisted of 3- and 13- amino acids residues, namely RGD and [5Ala]-indolicidine were synthetized. Monosubstituted hemin derivatives modificated by RGD, [5Ala]-indolicidine and gramicidine S were obtained. Biocide activity and low toxicity of obtained conjugates was shown.