Iron uptake pathway of as an entry route for peptide nucleic acids conjugated with a siderophore mimic.

Bacteria secrete various iron-chelators (siderophores), which scavenge Fe from the environment, bind it with high affinity, and retrieve it inside the cell. After the Fe uptake, bacteria extract the soluble iron(II) from the siderophore. Ferric siderophores are transported inside the cell via the TonB-dependent receptor system.

Strontium Ranelate and Strontium Chloride Supplementation Influence on Bone Microarchitecture and Bone Turnover Markers-A Preliminary Study.

Despite strontium ranelate use in osteoporosis management being one of the promising concepts in disease treatment, there is no clear evidence that strontium organic compounds are more effective than inorganic ones. The aim of this study was to compare strontium chlorate and strontium ranelate influence on the mice bone microarchitecture. We investigated whether strontium chlorate (7.

Structural dynamics influences the antibacterial activity of a cell-penetrating peptide (KFF)K.

Given the widespread demand for novel antibacterial agents, we modified a cell-penetrating peptide (KFF)K to transform it into an antibacterial peptide. Namely, we inserted a hydrocarbon staple into the (KFF)K sequence to induce and stabilize its membrane-active secondary structure. The staples were introduced at two positions, (KFF)K[5-9] and (KFF)K[2-6], to retain the initial amphipathic character of the unstapled peptide.

Conjugates of Aminoglycosides with Stapled Peptides as a Way to Target Antibiotic-Resistant Bacteria.

The misuse and overuse of antibiotics led to the development of bacterial resistance to existing aminoglycoside (AMG) antibiotics and limited their use. Consequently, there is a growing need to develop effective antimicrobials against multidrug-resistant bacteria. To target resistant strains, we propose to combine 2-deoxystreptamine AMGs, neomycin (NEO) and amikacin (AMK), with a membrane-active antimicrobial peptide anoplin and its hydrocarbon stapled derivative.

Stapled Anoplin as an Antibacterial Agent.

Anoplin is a linear 10-amino acid amphipathic peptide (Gly-Leu-Leu-Lys-Arg-Ile-Lys-Thr-Leu-Leu- ) derived from the venom sac of the solitary wasp. It has broad antimicrobial activity, including an antibacterial one. However, the inhibition of bacterial growth requires several dozen micromolar concentrations of this peptide.

Vitamin B - Peptide Nucleic Acid Conjugates.

Vitamin B (cobalamin, Cbl) is an essential nutrient for all mammals and some bacteria. From a chemical point of view, it is a highly functionalized molecule, which enables conjugation at multiple positions and attachment of various cargoes. Both mammalian and bacterial cells have developed a specific transport pathway for the uptake of vitamin B, and as a consequence, cobalamin is an attractive candidate for the delivery of biologically relevant molecules into cells.

Vitamin B-peptide nucleic acids use the BtuB receptor to pass through the Escherichia coli outer membrane.

Short modified oligonucleotides that bind in a sequence-specific way to messenger RNA essential for bacterial growth could be useful to fight bacterial infections. One such promising oligonucleotide is peptide nucleic acid (PNA), a synthetic DNA analog with a peptide-like backbone. However, the limitation precluding the use of oligonucleotides, including PNA, is that bacteria do not import them from the environment.

Conformational Changes of Anoplin, W-MreB, and (KFF)K Peptides near the Membranes.

Many peptides interact with biological membranes, but elucidating these interactions is challenging because cellular membranes are complex and peptides are structurally flexible. To contribute to understanding how the membrane-active peptides behave near the membranes, we investigated peptide structural changes in different lipid surroundings. We focused on two antimicrobial peptides, anoplin and W-MreB, and one cell-penetrating peptide, (KFF)K.

Crowded environment affects the activity and inhibition of the NS3/4A protease.

Kinetic parameters characterizing the catalytic activities of enzymes are typically investigated in dilute solutions. However, in reality, these reactions occur in cells that, in addition to water and ions, are full of other macromolecules including proteins, nucleic acids, lipids, and metabolites. Such a crowded environment might affect enzyme-catalyzed reaction rates, so it is necessary to mimic the crowd in laboratory settings.

Antibacterial Peptide Nucleic Acids-Facts and Perspectives.

Antibiotic resistance is an escalating, worldwide problem. Due to excessive use of antibiotics, multidrug-resistant bacteria have become a serious threat and a major global healthcare problem of the 21st century. This fact creates an urgent need for new and effective antimicrobials.

Does a Conjugation Site Affect Transport of Vitamin B -Peptide Nucleic Acid Conjugates into Bacterial Cells?

Gram-negative bacteria develop specific systems for the uptake of scarce nutrients, including vitamin B . These uptake pathways may be utilized for the delivery of biologically relevant molecules into cells. Indeed, it was recently reported that vitamin B transported an antisense peptide nucleic acid (PNA) into Escherichia coli and Salmonella Typhimurium cells.

Antimicrobial synergy between mRNA targeted peptide nucleic acid and antibiotics in E. coli.

A combination of antibacterial agents should make the emergence of resistance in bacteria less probable. Thus we have analyzed the synergistic effects between antibacterial antisense peptide nucleic acids (PNA) and conventional antibiotics against Escherichia coli AS19 (lipopolysaccharide defective) strain and a derivative of a pathogenic strain E. coli O157:H7.

[Recurrent urolithiasis as a symptom of primary hyperparathyroidism in a 16-year-old boy].

Unlabelled: Primary hyperparathyroidism is one of the most common endocrine diseases, however, it is rare in children. In most cases, it is caused by adenoma of these organs. Its most common complications include urolithiasis, nephrocalcinosis and osteoporosis.

Thermodynamics of the pseudo-knot in helix 18 of 16S ribosomal RNA.

A fragment of E. coli 16S rRNA formed by nucleotides 500 to 545 is termed helix 18. Nucleotides 505-507 and 524-526 form a pseudo-knot and its distortion affects ribosome function.

Interactions of 2'-O-methyl oligoribonucleotides with the RNA models of the 30S subunit A-site.

Synthetic oligonucleotides targeting functional regions of the prokaryotic rRNA could be promising antimicrobial agents. Indeed, such oligonucleotides were proven to inhibit bacterial growth. 2'-O-methylated (2'-O-Me) oligoribonucleotides with a sequence complementary to the decoding site in 16S rRNA were reported as inhibitors of bacterial translation.

Vitamin B as a carrier of peptide nucleic acid (PNA) into bacterial cells.

Short modified oligonucleotides targeted at bacterial DNA or RNA could serve as antibacterial agents provided that they are efficiently taken up by bacterial cells. However, the uptake of such oligonucleotides is hindered by the bacterial cell wall. To overcome this problem, oligomers have been attached to cell-penetrating peptides, but the efficiency of delivery remains poor.

Helix 69 of Escherichia coli 23S ribosomal RNA as a peptide nucleic acid target.

A fragment of 23S ribosomal RNA (nucleotides 1906-1924 in E. coli), termed Helix 69, forms a hairpin that is essential for ribosome function. Helix 69 forms a conformationally flexible inter-subunit connection with helix 44 of 16S ribosomal RNA, and the nucleotide A1913 of Helix 69 influences decoding accuracy.

Conformational Dynamics of Cyanocobalamin and Its Conjugates with Peptide Nucleic Acids.

Vitamin B also called cobalamin (Cbl) is an important enzymatic cofactor taken up by mammalian and also by many bacterial cells. Peptide nucleic acid (PNA) is a synthetic DNA analogue that has the ability to bind in a complementary manner to natural nucleic acids. Provided that PNA is efficiently delivered to cells, it could act as a steric blocker of functional DNA or RNA and regulate gene expression at the level of transcription or translation.

Synthesis and Preliminary Cytotoxicity Studies of 1-[1-(4,5-Dihydrooxazol- 2-yl)-1H-indazol-3-yl]-3-phenylurea and 3-phenylthiourea Derivatives.

Background: N-substituted 3-amino-1H-indazoles represent an interesting class of biologically active compounds. Among them, derivatives containing phenylurea moiety are of particular interest. Such compounds have been found to possess inhibitory activity against cancer cell growth.

Vitamin B12 Suitably Tailored for Disulfide-Based Conjugation.

Vitamin B12 has been proposed to be a natural vector for the in vivo delivery of biologically active compounds. Most synthetic methodologies leading to vitamin B12 conjugates involve functionalization at the 5' position via either carbamate-based linkages or using copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC), resulting in stable conjugates that are not cleaved within the cell. We have developed a novel vitamin B12 derivative suitably tailored for disulfide-based conjugation that can undergo cleavage in the presence of glutathione, the most abundant thiol in mammalian cells.

'Click' chemistry synthesis and capillary electrophoresis study of 1,4-linked 1,2,3-triazole AZT-systemin conjugate.

The Cu(I) catalyzed Huisgen 1,3-dipolar azide-alkyne cycloaddition (CuAAC) was applied for a nucleoside-peptide bioconjugation. Systemin (Sys), an 18-aa plant signaling peptide naturally produced in response to wounding or pathogen attack, was chemically synthesized as its N-propynoic acid functionalized analog (Prp-Sys) using the SPPS. Next, CuAAC was applied to conjugate Prp-Sys with 3'-azido-2',3'-dideoxythymidine (AZT), a model cargo molecule.

A peptide nucleic acid (PNA)-mediated polymerase chain reaction clamping allows the selective inhibition of the ERVWE1 gene amplification.

A new peptide nucleic acid (PNA) mediated QPCR technique for the detection and quantification of the Multiple Sclerosis-Associated Retrovirus (MSRV) belonging to the human endogenous retrovirus-W (HERV-W) family has been developed. The assay utilizes a PNA probe which is fully complementary to the ERVWE1 sequence, another member of the HERV-W family which is closely related to MSRV. Due to its excellent affinity to a completely matched template, PNA probe selectively blocks the amplification of ERVWE1 thus allowing the specific and exclusive detection and quantification of the MSRV as PNA does not interfere with the amplification of MSRV.

Synthesis and hybridization studies of a new CPP-PNA conjugate as a potential therapeutic agent in atherosclerosis treatment.

The objective of this study was to design and synthesize a new CPP-PNA conjugate that would be able to penetrate endothelial cells, bind STAT1 mRNA and thereby block the activity of STAT1 (the Signal Transducer and Activator of Transcription 1), which is important in cases of vessel inflammation. In the course of the study, the TAMRA-PTD-4- Hal(traziole-Gly-PNA)-conjugate was successfully synthesized using a specific 1,3-dipolar Huisgen cycloaddition reaction known as a "click reaction". The hybridization properties of the conjugate to complementary hSTAT1 mRNA and hSTAT1 ssDNA fragments was verified by capillary electrophoresis (CE).