Inactivated Flagellin-Containing Vaccine Efficacy against Ovine Enzootic Abortion.

Chlamydia abortus is the etiological agent of abortion and fetal loss in sheep, goats and bovine cattle in many countries. Even though commercially available vaccines can reduce the incidence in sheep, the development of new, safe, and effective vaccines remains high on the agenda. In this study, an evaluation was made of the efficacy of a vaccine candidate, an inactivated antigen based on the extract of outer membrane proteins of a C. abortus strain known as Chlamydia VNITIBP-21, in combination with recombinant flagellin as an adjuvant. Pregnant sheep (n = 43) were divided into three groups: an experimental vaccinated group, a control infected group and a control non-infected group. The sheep were vaccinated twice, with an interval of 3 weeks, then infected with the homologous virulent strain of Chlamydia abortus on pregnancy day 75. The vaccine candidate reduced C. abortus shedding in vaginal swabs considerably, in comparison with the control group. In addition, ewes in the experimental group experienced no abortions, while those in the control group experienced instances of abortion, as well as births of weak and nonviable lambs. The findings show that the vaccine candidate proved itself to be promising in combatting the agent of ovine abortion and fetal loss.

Protective Activity of Inactivated Rabies Vaccine Using Flagellin-Based Adjuvant.

Rabies is a zoonotic disease with high lethality. Most human deaths are associated with the bites received from dogs and cats. Vaccination is the most effective method of preventing rabies disease in both animals and humans. In this study, the ability of an adjuvant based on recombinant Salmonella typhimurium flagellin to increase protective activity of the inactivated rabies vaccine in mice was evaluated. A series of inactivated dry culture vaccine for dogs and cats "Rabikan" (strain Shchelkovo-51) with addition of an adjuvant at various dilutions were used. The control preparation was a similar series of inactivated dry culture vaccine without an adjuvant. Protective activity of the vaccine preparations was evaluated by the NIH potency test, which is the most widely used and internationally recommended method for testing effectiveness of the inactivated rabies vaccines. The value of specific activity of the tested rabies vaccine when co-administered with the adjuvant was significantly higher (48.69 IU/ml) than that of the vaccine without the adjuvant (3.75 IU/ml). Thus, recombinant flagellin could be considered as an effective adjuvant in the composition of future vaccine preparations against rabies virus.

Butyric acid and prospects for creation of new medicines based on its derivatives: a literature review.

The widespread use of antimicrobials causes antibiotic resistance in bacteria. The use of butyric acid and its derivatives is an alternative tactic. This review summarizes the literature on the role of butyric acid in the body and provides further prospects for the clinical use of its derivatives and delivery methods to the animal body. Thus far, there is evidence confirming the vital role of butyric acid in the body and the effectiveness of its derivatives when used as animal medicines and growth stimulants. Butyric acid salts stimulate immunomodulatory activity by reducing microbial colonization of the intestine and suppressing inflammation. Extraintestinal effects occur against the background of hemoglobinopathy, hypercholesterolemia, insulin resistance, and cerebral ischemia. Butyric acid derivatives inhibit histone deacetylase. Aberrant histone deacetylase activity is associated with the development of certain types of cancer in humans. Feed additives containing butyric acid salts or tributyrin are used widely in animal husbandry. They improve the functional status of the intestine and accelerate animal growth and development. On the other hand, high concentrations of butyric acid stimulate the apoptosis of epithelial cells and disrupt the intestinal barrier function. This review highlights the biological activity and the mechanism of action of butyric acid, its salts, and esters, revealing their role in the treatment of various animal and human diseases. This paper also discussed the possibility of using butyric acid and its derivatives as surface modifiers of enterosorbents to obtain new drugs with bifunctional action.

Photoinduced in situ generation of DNA-targeting ligands: DNA-binding and DNA-photodamaging properties of benzo[c]quinolizinium ions.

The photoreactions of selected styrylpyridine derivatives to the corresponding benzo[c]quinolizinium ions are described. It is shown that these reactions are more efficient in aqueous solution (97-44%) than in organic solvents (78-20% in MeCN). The quinolizinium derivatives bind to DNA by intercalation with binding constants of 6-11 × 104 M-1, as shown by photometric and fluorimetric titrations as well as by CD- and LD-spectroscopic analyses. These ligand-DNA complexes can also be established in situ upon irradiation of the styrylpyridines and formation of the intercalator directly in the presence of DNA. In addition to the DNA-binding properties, the tested benzo[c]quinolizinium derivatives also operate as photosensitizers, which induce DNA damage at relative low concentrations and short irradiation times, even under anaerobic conditions. Investigations of the mechanism of the DNA damage revealed the involvement of intermediate hydroxyl radicals and C-centered radicals. Under aerobic conditions, singlet oxygen only contributes to marginal extent to the DNA damage.

Development of novel cytoprotective small compounds inhibiting mitochondria-dependent cell death.

We identified cytoprotective small molecules (CSMs) by a cell-based high-throughput screening of Bax inhibitors. Through a medicinal chemistry program, M109S was developed, which is orally bioactive and penetrates the blood-brain/retina barriers. M109S protected retinal cells in ocular disease mouse models. M109S directly interacted with Bax and inhibited the conformational change and mitochondrial translocation of Bax. M109S inhibited ABT-737-induced apoptosis both in Bax-only and Bak-only mouse embryonic fibroblasts. M109S also inhibited apoptosis induced by staurosporine, etoposide, and obatoclax. M109S decreased maximal mitochondrial oxygen consumption rate and reactive oxygen species production, whereas it increased glycolysis. These effects on cellular metabolism may contribute to the cytoprotective activity of M109S. M109S is a novel small molecule protecting cells from mitochondria-dependent apoptosis both in vitro and in vivo. M109S has the potential to become a research tool for studying cell death mechanisms and to develop therapeutics targeting mitochondria-dependent cell death pathway.

DNA-based assemblies with bischromophoric styryl dye-chromene conjugates and cucurbit[7]uril.

Novel conjugates consist of 4-styrylpyridinium dye and 2,2-diphenyl-2H-chromene moiety were obtained, and their affinity to double stranded DNA and cucurbit[7]uril was investigated. With a combination of absorption, fluorescence and circular dichroism spectroscopies as well as MALDI-TOF mass spectrometry, we demonstrate that these compounds can interact with macromolecules to form of the supramolecular assemblies due to two suitable binding sites. The ternary complex is formed as a result of the intercalation of a positively charged styryl part between DNA base pairs, while cucurbit[7]uril is located on the alkyl chain between two moieties of conjugate. All these findings provide valuable information into controlling the interaction between organic molecules, DNA and cucurbit[7]uril.

Fluorescent RET-Based Chemosensor Bearing 1,8-Naphthalimide and Styrylpyridine Chromophores for Ratiometric Detection of Hg2+ and Its Bio-Application.

Dyad compound NI-SP bearing 1,8-naphthalimide (NI) and styrylpyridine (SP) photoactive units, in which the N-phenylazadithia-15-crown-5 ether receptor is linked with the energy donor naphthalimide chromophore, has been evaluated as a ratiometric fluorescent chemosensor for mercury (II) ions in living cells. In an aqueous solution, NI-SP selectively responds to the presence of Hg2+ via the enhancement in the emission intensity of NI due to the inhibition of the photoinduced electron transfer from the receptor to the NI fragment. At the same time, the long wavelength fluorescence band of SP, arising as a result of resonance energy transfer from the excited NI unit, appears to be virtually unchanged upon Hg2+ binding. This allows self-calibration of the optical response. The observed spectral behavior is consistent with the formation of the (NI-SP)·Hg2+ complex (dissociation constant 0.13 ± 0.04 µM). Bio-imaging studies showed that the ratio of fluorescence intensity in the 440-510 nm spectral region to that in the 590-650 nm region increases from 1.1 to 2.8 when cells are exposed to an increasing concentration of mercury (II) ions, thus enabling the detection of intracellular Hg2+ ions and their quantitative analysis in the 0.04-1.65 µM concentration range.

Heterobimetallic Ru(II)/M (M = Ag+, Cu2+, Pb2+) Complexes as Photosensitizers for Room-Temperature Gas Sensing.

This work is devoted to the investigation of heterobimetallic Ru(II) complexes as photosensitizers for room-temperature photoactivated In2O3-based gas sensors. Nanocrystalline In2O3 was synthesized by the chemical precipitation method. The obtained In2O3 matrix has a single-phase bixbyite structure with an average grain size of 13-14 nm and a specific surface area of 72 ± 3 m2/g. The synthesis of new ditope ligands with different coordination centers, their ruthenium complexes, and the preparation of heterobimetallic complexes with various cations of heavy and transition metals (Ag+, Pb2+, or Cu2+) is reported. The heterobimetallic Ru(II) complexes were deposited onto the surface of the In2O3 matrix by impregnation. The obtained hybrid materials were characterized by X-ray fluorescent analysis, FTIR spectroscopy, and optical absorption spectroscopy. The elemental distribution on the hybrids was characterized by energy-dispersive X-ray spectroscopy (EDS) mapping. The gas sensor properties were investigated toward NO2, NO, and NH3 at room temperature under periodic blue LED irradiation. It was identified that the nature of the second binding cation in Ru(II) heterobimetallic complexes can influence the selectivity toward different gases. Thus, the maximum sensor signal for oxidizing gases (NO2, NO) was obtained for hybrids containing Ag+ or Pb2+ cations while the presence of Cu2+ cation results in the highest and reversible sensor response toward ammonia. This may be due to the specific adsorption of NH3 molecules on Cu2+ cations. On the other hand, Cu2+ ions are proposed to be active sites for the reduction of nitrogen oxides to N2. This fact leads to a significant decrease in the sensor response toward NO2 and NO gases.

Fluorescence turn-on probes for intracellular DNA/RNA distribution based on asymmetric bis(styryl) dyes.

Two bis(styryl) dyes, varying in type of spacer between two mono(styryl) units, were tested for interactions with ct-DNA or cl-RNA. Both compounds showed strong affinity toward ds-DNA/ss-RNA, the binding mode of the interaction is shifting between DNA groove binding to RNA intercalation. Consequently, interaction with DNA shows a stronger flare-up of fluorescence (151 times for dye 1 and 118 times for dye 2) than when binding with RNA (23 times and 36 times correspondingly). The presence of energy transfer in the bis(styryl) system increases the Stokes shift of the dye, so when irradiating the system in the region of 370-380 nm, fluorescence is detected at 610-620 nm. The biological experiments showed that the efficient intracellular fluorescence quench was observed in the DNase digest test suggested that dyes can be applied by recognition of DNA in the presence of RNA molecules.

Novel Hybrid Benzoazacrown Ligand as a Chelator for Copper and Lead Cations: What Difference Does Pyridine Make.

A synthetic procedure for the synthesis of azacrown ethers with a combination of pendant arms has been developed and the synthesized ligand, characterized by various techniques, was studied. The prepared benzoazacrown ether with hybrid pendant arms and its complexes with copper and lead cations were studied in terms of biomedical applications. Similarly to a fully acetate analog, the new one binds both cations with close stability constants, despite the decrease in both constants. The calculated geometry of the complexes correlate with the data from X-ray absorption and NMR spectroscopy. Coordination of both cations differs due to the difference between the ionic radii. However, these chelation modes provide effective shielding of cations in both cases, that was shown by the stability of their complexes in the biologically relevant media towards transchelation and transmetallation.

Photochemical synthesis, intercalation with DNA and antitumor evaluation in vitro of benzo[d]thiazolo[3,2-a]quinolin-10-ium derivatives.

A new anticancer benzo[d]thiazolo[3,2-a]quinolin-10-ium derivatives were synthesized and characterized. Anticancer evaluation in vitro against four cancer cell lines including adenocarcinomic human alveolar basal epithelial cells (A549), hepatocellular carcinoma (HepG2), prostate cancer (PC3) and breast cancer (MCF7) indicated that some of prepared compounds shows higher selectivity in comparison with doxorubicin. DNA interaction studies by optical, CD, NMR spectroscopies showed the high affinity of benzothiazole ligands towards the dsDNA. The ligand-DNA interaction occurs through the intercalation of benzo[d]thiazolo[3,2-a]quinolin-10-ium derivatives with nucleic acid. The investigation of formed ligand - DNA complexes by docking and molecular dynamic calculations was applied for analysis of the relationship between structure and anticancer activity. The results suggested that benzo[d]thiazolo[3,2-a]quinolin-10-ium derivatives might serve as a novel scaffold for the future development to new antitumor agents.

Ratiometric Detection of Mercury (II) Ions in Living Cells Using Fluorescent Probe Based on Bis(styryl) Dye and Azadithia-15-Crown-5 Ether Receptor.

Bis(styryl) dye 1 bearing N-phenylazadithia-15-crown-5 ether receptor has been evaluated as a ratiometric fluorescent chemosensor for mercury (II) ions in living cells. In aqueous solution, probe 1 selectively responds to the presence of Hg2+ via the changes in the emission intensity as well as in the emission band shape, which is a result of formation of the complex with 1:1 metal to ligand ratio (dissociation constant 0.56 ± 0.15 µM). The sensing mechanism is based on the interplay between the RET (resonance energy transfer) and ICT (intramolecular charge transfer) interactions occurring upon the UV/Vis (380 or 405 nm) photoexcitation of both styryl chromophores in probe 1. Bio-imaging studies revealed that the yellow (500-600 nm) to red (600-730 nm) fluorescence intensity ratio decreased from 4.4 ± 0.2 to 1.43 ± 0.10 when cells were exposed to increasing concentration of mercury (II) ions enabling ratiometric quantification of intracellular Hg2+ concentration in the 37 nM-1 µM range.

Electron injection effect in In2O3 and SnO2 nanocrystals modified by ruthenium heteroleptic complexes.

In this work, the optical characteristics and conductivity under photoactivation with visible light of hybrids based on nanocrystalline SnO2 or In2O3 semiconductor matrixes and heteroleptic Ru(ii) complexes were studied. The heteroleptic Ru(ii) complexes were prepared based on 1H-imidazo[4,5-f][1,10]phenanthroline and 2,2'-bipyridine ligands. Nanocrystalline semiconductor oxides were obtained by chemical precipitation with subsequent thermal annealing and characterized by XRD, SEM and single-point BET methods. The heteroleptic Ru(ii) complexes as well as hybrid materials were characterized by time-resolved luminescence and X-ray photoelectron spectroscopy. The results showed that the surface modification of SnO2 nanoparticles with heteroleptic ruthenium complexes led to an increase in conductivity upon irradiation with light appropriate for absorption by organometallic complexes. In the case of In2O3, the deposition of Ru(ii) complexes resulted in a decrease in conductivity, apparently due to the special structure of the surface layer of the semiconductor.

Cucurbit[7]uril-driven modulation of ligand-DNA interactions by ternary assembly.

The design of small organic molecules with a predictable and desirable DNA-binding mechanism is a topical research task for biomedicine application. Herein, we demonstrate an attractive supramolecular strategy for controlling the non-covalent ligand-DNA interaction by binding with cucurbituril as a synthetic receptor. With a combination of UV/vis, CD and NMR experiments, we demonstrate that the bis-styryl dye with two suitable binding sites can involve double stranded DNA and cucurbituril in the formation of the supramolecular triad. The ternary assembly is formed as a result of the interaction of macrocyclic cucurbituril with one pyridinium fragment of the bis-styryl dye, while the second pyridinium fragment of the dye is effectively associated with DNA backbones, which leads to a change in the ligand-DNA binding mode from aggregation to a minor groove. This exciting outcome was supported by molecular docking studies that help to understand the molecular orientation of the supramolecular triad and elucidate the destruction of dye aggregates caused by cucurbituril. These studies provide valuable information on the mechanisms of DNA binding to small molecules and recognition processes in bioorganic supramolecular assemblies constructed from multiple non-covalent interactions.

Encapsulation-Controlled Photoisomerization of a Styryl Derivative: Stereoselective Formation of the Anti Z-Isomer in the Cucurbit[7]uril Cavity.

The photochemical isomerization of a styrylpyridinium dye (SP) bearing an unsymmetrically attached benzo-15-crown-5 ether has been studied in aqueous solution in the absence and presence of cucurbit[7]uril (CB[7]). The detailed analysis of the UV/Vis and NMR spectra showes that the isomeric composition of the photostationary mixtures of SP can be modulated by the host-guest complexation with CB[7]. It was found that steric hindrance caused by encapsulation of SP in the host cavity induces the exclusive formation of the anti conformer of Z-SP in contrast with the mixture of both anti and syn conformers obtained during photoisomerization of the dye without CB[7]. Remarkably, the displacement of anti Z-SP from CB[7] does not lead to the transformation of the anti Z-isomer into the syn Z-isomer pointing out the conformational memory of the system. The results provide an interesting example of the supramolecular stereorecognition by the achiral CB[7] host.

Benzoazacrown compound: a highly effective chelator for therapeutic bismuth radioisotopes.

A new benzoazacrown ligand H4BATA was synthesized and its complexation ability towards bismuth cations was evaluated. Binding of cation occurs at room temperature in a few minutes and formed complex exhibits the same level of inertness as highly stable complex with the well-known H4DOTA in biologically relevant and challenging media under in vivo conditions.

The regioselective [2 + 2] photocycloaddition reaction of 2-(3,4-dimethoxystyryl)quinoxaline in solution.

Herein, the [2 + 2] photocycloaddition between two molecules of (E)-2-(3,4-dimethoxystyryl)-quinoxaline (1) in an acetonitrile solution to form only one cyclobutane isomer out of eleven possible isomers is described. The observed photocycloaddition reaction is reversible; thus, the studied photocycloaddition reaction can be considered as a photoreversible photochromic process. The removal of two methoxy groups from the (E)-2-(3,4-dimethoxystyryl)quinoxaline (1) structure produces compound 2, which participates only in the photoisomerization reaction. The change of the quinoxaline residue in 1 to quinoline results in the formation of compound 3, which demonstrates the regioselective oxidization electrocyclic transformation through the formation of a novel C-N bond.

A novel bacteriochlorin-styrylnaphthalimide conjugate for simultaneous photodynamic therapy and fluorescence imaging.

Propargyl-152,173-dimethoxy-131-amide of bacteriochlorin e (BChl) and a 4-(4-N,N-dimethylaminostyryl)-N-alkyl-1,8-naphthalimide bearing azide group in the N-alkyl fragment were conjugated by the copper(i)-catalyzed 1,3-dipolar cycloaddition to produce a novel dyad compound BChl-NI for anticancer photodynamic therapy (PDT) combining the modalities of a photosensitizer (PS) and a fluorescence imaging agent. A precise photophysical investigation of the conjugate in solution using steady-state and time-resolved optical spectroscopy revealed that the presence of the naphthalimide (NI) fragment does not decrease the photosensitizing ability of the bacteriochlorin (BChl) core as compared with BChl; however, the fluorescence of naphthalimide is completely quenched due to resonance energy transfer (RET) to BChl. It has been shown that the BChl-NI conjugate penetrates into human lung adenocarcinoma A549 cells, and accumulates in the cytoplasm where it has a mixed granular-diffuse distribution. Both NI and BChl fluorescence in vitro provides registration of bright images showing perfectly intracellular distribution of BChl-NI. The ability of NI to emit light upon excitation in imaging experiments has been found to be due to hampering of RET as a result of photodestruction of the energy acceptor BChl unit. Phototoxicity studies have shown that the BChl-NI conjugate is not toxic for A549 cells at tested concentrations (<8 µM) without light-induced activation. At the same time, the concentration-dependent killing of cells is observed upon the excitation of the bacteriochlorin moiety with red light that occurs due to reactive oxygen species formation. The presented data demonstrate that the BChl-NI conjugate is a promissing dual function agent for cancer diagnostics and therapy.

Light-induced piston nanoengines: ultrafast shuttling of a styryl dye inside cucurbit[7]uril.

The combination of photoactive styryl(pyridinium) dyes and cucurbit[7]uril (CB[7]) in an integrated supramolecular system allowed us to design a novel high speed molecular machine based on the fully reversible shuttling motion of the dye inside the CB[7] host cavity. The driving force of this movement is the electrostatic potential change after the occurrence of intramolecular charge transfer in the excited state of the dye molecule that can be externally controlled by light. Steady-state and time-resolved optical spectroscopy as well as DFT calculations provided an unambiguous evidence for the ultrafast piston-like movement of the system between two states. The shuttling process occurs in the picosecond timescale and its bistability depends on the strength of the dye donor fragment.

Controlling photophysics of styrylnaphthalimides through TICT, fluorescence and E,Z-photoisomerization interplay.

The photophysical properties of naphthalimide dyes NI1-3 with electron releasing 4-methoxy- (NI1), 3,4-dimethoxystyryl- (NI2) and dimethylaminostyryl (NI3) groups are examined in a variety of protic and aprotic solvents. All compounds demonstrate positive solvatochromism in the steady-state absorption and fluorescence spectra. The analysis of the dependence of the Stokes shift on the polarity of the solvent using the Lippert-Mataga equation allowed us to determine the change in the dipole moment upon excitation. The obtained data correspond to the formation of highly polar charge transfer states. Based on the transient absorption spectra and time-resolved fluorescence measurements, the presence of two different emissive states was definitely proved. The primarily formed planar Local Excited (LE) state dominates in non-polar solvents like cyclohexane and toluene where it relaxes mostly through fluorescence and E,Z-isomerisation pathways. In polar solvents, an alternative relaxation channel emerges that consists of twisting around single bond between styryl and naphthalimide fragments, which leads to the formation of a Twisted Intramolecular Charge Transfer (TICT) state. The factors affecting the fluorescence of TICT states are discussed. The observed spectral effects are rationalized using quantum-chemical calculations, X-ray data and NMR spectroscopy.