10 research outputs found
The mechanisms of complement activation in normal bovine serum and normal horse serum against Yersinia enterocolitica O:9 strains with different outer membrane proteins content
Yersinia enterocolitica is a common zoonotic pathogen and facultative intracellular bacterium which
can survive within blood cells. Cattle and horses are considered a reservoir of Y. enterocolitica which
often causes several serious syndromes associated with yersiniosis such as abortions, premature births or
infertility. The aim of our investigation was to determine the vitality of Y. enterocolitica O:9 strains
(Ye9) in bovine and horse sera (NBS and NHrS) and explain the role of outer membrane proteins
(OMPs) in serum resistance of these bacteria. Our previous studies demonstrated moderate human
serum (NHS) resistance of the wild type Ye9 strain, whereas mutants lacking YadA, Ail or OmpC
remained sensitive to the bactericidal activity of NHS. The present study showed that the wild type of
Ye9 strain was resistant to the bactericidal activity of both NHrS and NBS, while Ye9 mutants lacking
the YadA, Ail and OmpC proteins were sensitive to NHrS and NBS as well as to NHS. The mechanisms
of complement activation against Ye9 strains lacking Ail and YadA were distinguished, i.e. activation
of the classical/lectin pathways decisive in the bactericidal mechanism of complement activation of
NBS, parallel activation of the classical/lectin and alternative pathways of NHrS. In this research the
mechanism of independent activation of the classical/lectin or the alternative pathway of NBS and
NHrS against Ye9 lacking OmpC porin was also established. The results indicate that serum resistance
of Ye9 is multifactorial, in which extracellular structures, i.e. outer membrane proteins (OMPs) such as
Ail, OmpC or YadA, play the main role
Insight into tick biocontrol with special regard to fungi
The epidemiological and epizootic importance of ticks has been known for a few decades since of the
discovery of their role as vectors of many new diseases, and the better detection of those already known. Given the
durability of chemical preparations in the environment and the increasing problem of developing tick resistance, natural
strategies for biological control are sought. A promising alternative to chemical pesticides is the use of
entomopathogenic organisms for effective integrated pest management of low environmental impact. A number of
promising microbes have been identified during the search for effective means of controlling the tick population, but
the knowledge about the impact of these pathogens on the environment and other non-target organisms is still
insufficient. Previous research has still not provided a definite answer about the safety of their use. It is known, however,
that the chemicals which are currently used have a negative impact on the environment and/or cause resistance. No
efficient biocompound has yet been devised for commercial use. Potential microorganisms for tick biocontrol (mainly
bacteria and fungi) are natural tick pathogens, living in the same environment. With their adhesive properties, and their
ability to digest the cuticle, they may constitute an appropriate ingredient of bioacaricides. Until now, fungal insecticides
have been used only to control crop pests
Phosphine derivatives of sparfloxacin : synthesis, structures and in vitro activity
We synthesized two derivatives of sparfloxacin (HSf): aminomethyl(diphenyl)phosphine (PSf) and its oxide (OPSf). The compounds were characterized by NMR spectroscopy, MS and elemental analysis. In addition, the molecular structures of the compounds were determined using DFT and X-ray (OPSf) analysis. The antibacterial activity of HSf and both derivatives was tested against four reference and fifteen clinical Gram-positive and Gram-negative strains of bacteria (sensitive or resistant to fluoroquinolones). The results showed that the activity of PSf was similar to or higher than the activity of HSf, while OPSf was found significantly less active. The compounds were also tested in vitro toward the following cancer cell lines: mouse colon carcinoma (CT26) and human lung adenocarcinoma (A549). Regardless of the cancer cell line, derivatization of HSf resulted in the gradual increase of cytotoxicity. OPSf exhibited the highest one (4 h – incubation time: IC50(CT26) = 51.0 ± 1.2; IC50(A549) = 74.9 ± 1.4 and 24 h: IC50(CT26) = 109.2 ± 8.8; IC50(A549) = 52.7 ± 9.2)
Antibactericidal Ir(III) and Ru(II) Complexes with Phosphine-Alkaloid Conjugate and Their Interactions with Biomolecules: A Case of N-Methylphenethylamine
The phosphine ligand (Ph2PCH2N(CH3)(CH2)2Ph, PNMPEA) obtained by the reaction of the (hydroxymethyl)diphenylphosphine with naturally occurring alkaloid N-methylphenethylamine, was used to synthesize the half-sandwich iridium(III) (Ir(η5-Cp*)Cl2Ph2PCH2N(CH3)(CH2)2Ph, IrPNMPEA) and ruthenium(II) (Ru(η6-p-cymene)Cl2Ph2PCH2N(CH3)(CH2)2Ph, RuPNMPEA) complexes. They were characterized using a vast array of methods, including 1D and 2D NMR, ESI(+)MS spectrometry, elemental analysis, cyclic voltammetry (CV), electron spectroscopy in the UV-Vis range (absorption, fluorescence) and density functional theory (DFT). The initial antimicrobial activity in vitro toward Gram-positive and Gram-negative bacterial strains was examined, indicating that both complexes are selective towards Gram-positive bacteria, e. g., Staphylococcus aureus, where the IrPNMPEA has been more bactericidal compared to RuPNMPEA. Additionally, the interactions of these compounds with various biomolecules, such as DNA (ctDNA, plasmid DNA, 9-ethylguanine (9-EtG), and 9-methyladenine (9-MeA)), nicotinamide adenine dinucleotide (NADH), glutathione (GSH), and ascorbic acid (Asc) were described. The results showed that both Ir(III) and Ru(II) complexes accelerate the oxidation process of NADH, GSH and Asc that appeared to occur by an electron transfer mechanism. Interestingly, only IrPNMPEA leads to the formation of various biomolecule adducts, which can explain its higher activity. Furthermore, RuPNMPEA and IrPNMPEA have been interacting with the DNA through weak noncovalent interaction
Phosphine derivatives of ciprofloxacin and norfloxacin, a new class of potential therapeutic agents
In this paper a new series of chalcogenides of diphenylmethylaminophosphine derived from
ciprofloxacin (PPh
2
CH
2
Cp) and a new phosphine derived from norfloxacin (PPh
2
CH
2
Nr) are presented.
The synthesized compounds were characterized by N
MR, MS and X-ray techniques. Both phosphines exhibit
antibacterial activity against:
S. aureus
,
E. coli
,
K. pneumoniae
and
P. aeruginosa
, similar to ciprofloxacin and
norfloxacin. They inhibit the growth of microorganisms
in relatively low concentrations. Chalcogenides are
slightly less active than phosphines and unmodified a
ntibiotics. All the derivatives were also tested
in vitro
as
anticancer agents towards mouse colon carcinoma (CT26) and human lung adenocarcinoma (A549).
Cytotoxicity studies revealed that phosphines and their chalcogenides are able to inhibit the proliferation
of the cells at relatively low concentrations. Moreover, all the tested compounds are more active against
tested cell lines than cisplatin – the main representative of antitumor drugs