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PubMed1997

Evaluation of chromatin condensation in human spermatozoa: a flow cytometric assay using acridine orange staining.

The quality of sperm chromatin is an important factor in fertilization and is especially critical where one spermatozoon is artificially selected for fertilizing an egg (as in intracytoplasmic sperm injection). In this study, flow cytometry after staining of human spermatozoa with Acridine Orange was used to study chromatin structure. A method is described for estimating the percentage of cells in a human sperm sample that have completed epididymal maturation in regard to chromatin condensation. Of the 121 samples of the semen that were examined, nine contained a higher percentage of hypocondensed spermatozoa and six samples contained elevated amounts of hypercondensed spermatozoa. In addition to aberrancies in chromatin condensation other defects showed up as satellite populations of spermatozoa with higher than normal ratios of red/green fluorescence after Acridine Orange staining. Such defects were found in 15 semen samples. The use of swim-up and Percoll gradient centrifugation methods was shown to improve the percentage of spermatozoa with normal chromatin structure in some samples with poor initial quality.

Acridine Orange↗
PubMed1991

Synthesis and physicochemical properties of oligonucleotides built with either alpha-L or beta-L nucleotides units and covalently linked to an acridine derivative.

Modified deoxynucleosides 2'-deoxy-beta-L-uridine, beta-L-thymidine, alpha-L-thymidine, 2'-deoxy-beta-L-adenosine and 2'-deoxy-alpha-L-adenosine were synthesized and assembled as homooligomers, respectively: octa-beta-L-deoxyuridylates, octa beta-L and alpha-L-thymidylates and tetra beta-L and alpha-L-deoxyadenylates. These unnatural oligomers were then substituted with an acridine derivative. The binding studies of these modified oligonucleotides with D-ribo- and D-deoxyribopolynucleotides were carried out by absorption spectroscopy. While beta-L-d(Up)8m5Acr, beta-L-(Tp)8m5Acr, alpha-L-(Tp)8m5Acr did not interact with poly(rA) and poly(dA), beta-L-d(Ap)4m5Acr and alpha-L-d(Ap)4m5Acr did form double and triple helices with poly(rU) and poly(dT), respectively. Their stability towards nuclease digestion was studied through comparison with that of octa-beta-D-thymidylate and tetra beta-D-deoxyadenylate covalently linked to an acridine derivative. One endonuclease (nuclease P1 from Penicillium citrinum) and two exonucleases (a 3'-exonuclease from Crotalus durissus venom and a 5'-exonuclease extracted from calf thymus) were employed. beta-L- and alpha-L-oligomers demonstrate a high resistance toward nuclease digestion.

Acridines↗
PubMed1979

Atomic resolution analysis of a 2:1 complex of CpG and acridine orange.

Cytidylyl-3', 5'-guanosine and acridine orange crystallize in a highly-ordered triclinic lattice which diffracts X-rays to 0.85 angstrom resolution. The crystal structure has been solved and refined to a residual factor of 9.5%. The two dinucleoside phosphate molecules form an antiparallel double helix with the acridine orange intercalated between them. The two base pairs of the double helical fragment have a twist angle of 10 degrees and it is found to have a C3' endo-(3', 5')-C2' endo mixed sugar puckering along the nucleotide backbone as has been observed for other simple intercalator complexes. Twenty-five water molecules have been located in the lattice together with a sodium ion. The intercalator double helical fragments form sheets which are held together by van der Waals interactions in one direction and hydrogen bonding interactions in the other. The crystal lattice contains aqueous channels in which sixteen water molecules are hydrogen bonded to the nucleotide, none to the intercalator, five water molecules are coordinated about the sodium ion and four water molecules bind solely to other water molecules. The bases in the base pairs have a dihedral angle of 7 to 8 degrees between them.

Acridine Orange↗
PubMed2003

Unusual intercalation of acridin-9-ylthiourea into the 5'-GA/TC DNA base step from the minor groove: implications for the covalent DNA adduct profile of a novel platinum-intercalator conjugate.

The binding of the novel cytotoxic acridine derivative, 1-[2-(acridin-9-ylamino)ethyl]-1,3-dimethylthiourea (ACRAMTU) to various self-complementary oligonucleotide duplexes has been studied by combined high-resolution NMR spectroscopy/restrained molecular dynamics and equilibrium binding assays to establish the sequence and groove specificity of intercalation. The binding mode in the sequences d(GGACGTCC)(2) and d(GGAGCTCC)(2) was deduced from chemical shift changes and intermolecular NOEs between the ligand and the oligonucleotides. ACRAMTU intercalated into the 5'-CG/CG and 5'-GA/TC base steps, and penetration of the duplexes occurred from the minor groove. Intercalation of ACRAMTU in d(GGTACC)(2) occurs at the central TA/TA step, based on the absence of the internucleotide A4H8-T3H1' and A4H8-T3H3' cross-peaks in the 1:1 complex of this sequence. An energy- minimized AMBER model of the 1:2 complex, [d(GGAGCTCC)(2)(ACRAMTU)(2)], was generated, which was based on restricted molecular dynamics/ mechanics calculations using 108 NOE distance restraints (including 11 DNA-drug distances per ligand). Equilibrium dialysis experiments were performed using octamers containing various base steps present in the 'NMR sequences'. The highest affinity for ACRAMTU was observed in d(TATAT ATA)(2), followed by d(CGCGCGCG)(2) and d(GAG ATCTC)(2). The binding levels for CG/CG and GA/TC were virtually the same. The unusual tolerance of the GA/TC intercalation site and the pronounced groove specificity of ACRAMTU play a significant role in the molecular recognition between the corresponding platinum conjugate, Pt-ACRAMTU, and DNA.

Acridines↗
PubMed2005

Characterization of the bisintercalative DNA binding mode of a bifunctional platinum-acridine agent.

The DNA interactions of PT-BIS(ACRAMTU) ([Pt(en)(ACRAMTU)2](NO3)4; ACRAMTU = 1-[2-(acridin-9-ylamino)ethyl]-1,3-dimethylthiourea, en = ethylenediamine), a bifunctional platinum-acridine conjugate, have been studied in native and synthetic double-stranded DNAs and model duplexes using various biophysical techniques. These include ethidium-DNA fluorescence quenching and thermal melting experiments, circular dichroism (CD) spectroscopy and plasmid unwinding assays. In addition, the binding mode was studied in a short octamer by NMR spectroscopy in conjunction with molecular modeling. In alternating copolymers, PT-BIS(ACRAMTU) shows a distinct preference for poly(dA-dT)2, which is approximately 3-fold higher than that of ACRAMTU. In the ligand-oligomer complex, d(GCTATAGC)2.PT-BIS(ACRAMTU) (complex I*), PT-BIS(ACRAMTU) increases the thermal stability of the B-form host duplex by DeltaT(m) > 30 K (CD and UV melting experiments). The agent unwinds pSP73 plasmid DNA by 44(+/-2) degrees per bound molecule, indicating bisintercalative binding. A 2-D NMR study unequivocally demonstrates that PT-BIS(ACRAMTU)'s chromophores deeply bisintercalate into the 5'-TA/TA base pair steps in I*, while the platinum linker lies in the minor groove. An AMBER model reflecting the NMR results shows that bracketing of the central AT base pairs in a classical nearest neighbor excluded fashion is feasible. PT-BIS(ACRAMTU) inhibits DNA hydrolysis by BstZ17 I at the enzyme's restriction site, GTA downward arrowTAC. Possible consequences for other relevant DNA-protein interactions, such as those involved in TATA-box-mediated transcription initiation and the utility of the platinum-intercalator technology for the design of sequence-specific agents are discussed.

Acridines↗
PubMed2003

Tandem site-selective RNA scission utilizing acridine-DNA conjugates.

Useful technique to clip designated short RNA fragments from long substrates has been prepared by combining oligonucleotides bearing two acridine groups and lanthanide(III) ions. The substrate RNA is site-selectively activated at two designated phosphodiester linkages by complementary bis-acridine-modified DNA, and is promptly cleaved by lanthanide(III) ions to produce short RNA fragment between the two scission sites. By applying this technique, efficient genotyping method for single nucleotide polymorphism (SNP) have been developed.

Acridines↗
PubMed2003

The effect of acridine moiety for binding and reaction of Cu(II)[1 ,4,7-triazacyclononane] with DNA.

The orientation and the dynamic behavior of Cu(II) complex of 1,4,7-triazacyclononane ([9]aneN3) and its acridine conjugate on B-form DNA fiber have been investigated by EPR spectroscopy. It has been shown that a Cu([9]aneN3)2+ binds to DNA with two different binding modes at room temperature; one species is rapidly moving and the other is immobilized randomly on the DNA. An introduction of acridine to 1,4,7-triazacyclononane fixed the orientation of all the Cu(II) complex with the g// axis perpendicular to DNA fiber axis, indicating that the tetragonal coordination plane is almost parallel to the DNA double helical axis.

Acridines↗
PubMed2004

Simultaneous use of highly acidic acridine and rigid chiral linker for efficient site-selective RNA scission.

To the middle of oligonucleotide, 9-amino-2-methoxy-6-nitroacridine (pKa = 8.8) and 9-amino-6-chloro-2-methoxyacridine (pKa = 10.5) were tethered through three linkers, and the abilities of these conjugates for site-selective activation of RNA (inducing site-selective scission by Lu(III)) were compared. The RNA-activating ability was strongly dependent on both the acidity of acridine and the structure of linker. Combination of highly acidic acridine and rigid chiral linker leads to unprecedented efficient site-selective RNA activation.

Acridines↗
PubMed1981

Conformational studies of Escherichia coli ribosomes with the use of acridine orange as a probe.

The interaction of E. coli vacant ribosomes with acridine orange (AO) was studied, to obtain conformational information about rRNAs in ribosomes. Acridine orange binds to an RNA in two different modes: cooperative outside binding with stacking of bound AO's and intercalation between nucleotide bases. Free 16S and 23S rRNAs have almost identical affinities to AO. At 1 mM Mg2+, AO can achieve stacking binding on about 40% of rRNA phosphate groups. The number of stacking binding sites falls to about 1/3 in the 30S subunit in comparison with free 16S rRNA. In the 50S subunit, the number of stacking binding sites is only 1/5 in comparison with free 23S rRNA. Mg2+ ions are more inhibitory for the binding of AO to ribosomes than to free rRNAs. The strength of stacking binding appears to be more markedly reduced by Mg2+ in active ribosomes than in rRNAs. "Tight couple" 70S particles are less accessible for stacking binding than free subunits. The 30S subunits that have irreversibly lost the capability for 70S formation under low Mg2+ conditions have an affinity to AO that is very different from that of active 30S but similar to that of free rRNA, though the number of stacking binding sites is little changed by the inactivation. 70S and 30S ribosomes with stacking bound AO's have normal sedimentation constants, but the 50S subunits reversibly form aggregates.

Acridine Orange↗
PubMedDate not supplied

Precise diagnosis of infection in burn wound biopsy specimens. Combination of histologic technique, acridine orange staining, and culture.

This study developed a rapid manual histologic technique on burn wound biopsy specimens for an early diagnosis of infection. A total of 86 biopsy specimens were processed using this rapid manual method, acridine orange fluorescent staining for the detection of microorganisms, and a quantitative culture for the identification and counting of bacteria in adjacent homogenized biopsy specimens. Use of these three techniques has shown their complementarity for the evaluation of sepsis in burn wound patients. The histologic study allowed a classification of the depth of bacterial involvement 4 hours after specimen collection, whereas the acridine orange fluorescent staining was useful for quantitative evaluation of infection in the same delay. Thus a rapid therapeutic decision can be made while waiting for the results of quantitative culture and sensitivity tests, which require 24 to 48 hours. We propose routine monitoring of burned patients consisting of these three tests performed simultaneously on each biopsy specimen.

Acridine Orange↗
PubMed1975

Effect of inorganic phosphate on acridine inhibition and plasmid curing in Escherichia coli.

Some mutants and stock strains of Escherichia coli K12 were sensitive to acriflavine in the presence of inorganic phosphate but were resistant to acriflavine in its absence. They mutated spontaneously to resistance to acriflavine plus phosphate. The synergistic effect of phosphate on acriflavine sensitivity was increased at high pH values. Genetic analysis suggested that the mutations occurred in the gene acrA. Electron microscopic observation suggested that the presence of acriflavine plus phosphate affected the structure of the plasma membrane and the cytoplasm under it. This structural alteration was not caused by acriflavine alone. Acridine orange plus phosphate can more effectively eliminate the plasmid F8-gal+ than acridine orange alone.

Acridines↗
PubMed2005

9-(2,6-dichlorophenoxycarbonyl)-10-methylacridinium trifluoromethanesulfonate and its precursor 2,6-dichlorophenyl acridine-9-carboxylate.

The title compounds, C21H14Cl2NO2+.CF3O3S-, (I), and C20H11Cl2NO2, (II), form triclinic crystals. Adjacent cations of (I) are oriented either parallel or antiparallel; in the latter case, they are related by a centre of symmetry. Together with the CF3SO3- anions, the antiparallel-oriented cations of (I) form layers in which the molecules are linked via a network of C-H...O and pi-pi interactions (between the benzene rings). These layers, in turn, are linked via a network of multidirectional pi-pi interactions between the acridine rings, and the whole lattice is stabilized by electrostatic interactions between ions. Adjacent molecules of (II) are oriented either parallel or antiparallel; in the latter case, they are related by a centre of symmetry. Parallel-oriented molecules are arranged in chains stabilized via C-H...Cl interactions. These chains are oriented either parallel or antiparallel and are stabilized, in the latter case, via multidirectional pi-pi interactions and more generally via dispersive interactions. Acridine and independent benzene moieties lie parallel in the lattices of (I) and (II), and are mutually oriented at an angle of 33.4 (2) degrees in (I) and 9.3 (2) degrees in (II).

Acridines↗
PubMed2005

2-(Acridin-9-ylimino)-3-dimethylamino-1,3-thiazolidin-4-one.

In the title compound, C18H16N4OS, prepared by the reaction of 4-(acridin-9-yl)-1,1-dimethylthiosemicarbazide with methyl bromoacetate, the acridine and thiazolidine ring systems are both non-planar and, because of steric requirements, almost perpendicular, with a dihedral angle between their planes of 99.69 (6) degrees. C-H...O and C-H...pi(arene) hydrogen bonds stabilize the crystal structure in the solid state.

Acridines↗
PubMedDate not supplied

In vitro cytophotometry evaluation of gamma-radiation effects on human sperm cell by acridine orange staining.

Effects of gamma-radiations on human sperm nuclei in vitro were studied by cytophotometrical quantification on fixed smears stained by acridine orange some of which had undergone heat-treatment. Following irradiations at different doses (0.0, 2.5, 5.0, 7.5 gy) using a cobalt source, changes in distribution of acridine orange fluorescences emitted by nuclei (total fluorescence greater than 515 nm versus green fluorescence = 525 nm) appeared to be dose-dependent. Heat-treatment of irradiated heads was confirmed to be a complementary procedure necessary for a good evaluation of the initial degree in chromatin compactness. Chromatin alterations related to changes in emitted fluorescence could be due to the initial fragility of the DNA-nucleoprotein complex. These preliminary results suggest that the normality of sperm chromatin could be used as a biologic dosimeter.

Acridine Orange↗
PubMedDate not supplied

Chromatin condensation in cat spermatozoa during epididymal transit as studied by aniline blue and acridine orange staining.

Chromatin stability and DNA-resistance to acidic denaturation was evaluated by acidic aniline blue and acridine orange staining of cat sperm from different regions of the epididymis. The results were related to conventional sperm parameters. The percentage of aniline blue-stained spermatozoa (persisting histones) decreased significantly from the caput to the cauda region (31.8% and 7.8%, respectively; P<0.0001). The percentage of stained heads of cauda sperm was much lower in populations of morphologically normal forms than in those with abnormal forms (4.1% and 13.8%, respectively, P<0.0001). Among spermatozoa with abnormalities, the percentage of stained heads was significantly higher in cells with head abnormalities than in sperm with only tail abnormalities (87.1% and 10.3%, respectively; P>0.0001). With acridine orange fluorescence staining, 86.5% of cauda epididymal region (51.1%) to the cauda epididymal region (86.5%). The percentage of cauda epididymal sperm with normal condensed chromatin was neither linked to testicular sperm count, motility nor to age of the cats. The parameter of chromatin condensation and stability can be a valuable index of sperm quality, reflecting the possible disorders of spermatogenesis and epididymal sperm maturation, frequently observed in feline species.

Acridine Orange↗
PubMed1977

Differential staining of bacteria in clinical specimens using acridine orange buffered at low pH.

Optimal conditions for acridine orange staining of air dried and methanol fixed bacteria on glass slides were studied. The pH of the staining buffer did not influence the fluorescence of an S. aureus and an E. coli strain at dye concentrations of 25-50 mg per litre. 81 bacterial strains representing 15 different species were stained with acridine orange under standard conditions, all strains showing orange fluorescence. The pH of the buffer influenced markedly the staining patterns of human cells and tissue materials, as represented by smears of peripheral blood, buccal scrapings, urethral secretions and tracheal exudates. The fluorescence obtained ranged from low intensity green at low pH values to bright orange at neutral and alkaline pH. This variability indicated a possibility of designing conditions for a differential staining method for the detection of bacteria in clinical specimens. The differential staining effect with a low pH in the buffer was confirmed on smears of buccal scrapings, cerebrospinal fluid samples and urethral secretions, showing orange fluorescence of the bacteria present and green-to-yellow fluorescence of background material, cells and tissue debris.

Acridines↗
PubMed1991

Secretin dissipates red acridine orange fluorescence from pancreatic duct epithelium.

This study was undertaken to elucidate whether duct cells in the pancreas contain acidic cytoplasmic compartments regulated by secretin. Microdissected pancreatic ducts from pigs were examined by acridine orange (AO) and 2',7'-biscarboxyethyl-5(6)-carboxyfluorescein/tetraacetoxymethy l ester (BCECF/AM) epifluorescence microscopy. Estimated cytoplasmic pH using BCECF fluorescence was 7.43 +/- 0.04 and was not changed by altering CO2 tension in the incubation medium. The epithelium of acridine orange incubated peripheral interlobular pancreatic ducts exhibited green and red fluorescence; the colour depending on the experimental conditions. Red epithelial fluorescence was seen in resting pancreatic ducts and was greatly accentuated by raising CO2 in the incubation medium from 5.5 to 10 kPa. The red fluorescence was abolished by secretin, or following incubation with chloroquine or NH4Cl or the protonophores carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) or carbonyl cyanide m-chlorophenylhydrazone (CCCP), leaving uniform green fluorescence. These findings suggest that pancreatic duct cells contain CO2-dependent acidic compartments which vanish during secretin stimulation and which may be cytoplasmic tubulovesicles.

Acridine Orange↗
PubMed1973

Relationships between curing of the F episome by rifampin and by acridine orange in Escherichia coli.

Subinhibitory doses of rifampin cured F(+)Escherichia coli cells from the episome. The target of the drug was transcription because E. coli mutants with a ribonucleic acid polymerase resistant to rifampin were not cured. The experimental conditions required for optimal curing with rifampin very closely resembled those required for curing with acridine orange. Mutants were found which are more resistant to curing by both acridine orange and rifampin. Probably the two drugs affect a common metabolic step, or alternatively they may inhibit the synthesis of a factor which is necessary for the replication of the episome.

Acridines↗