Mechanistic investigations reveal that dibromobimane extrudes sulfur from biological sulfhydryl sources other than hydrogen sulfide

Hydrogen sulfide (H₂S) has emerged as an important biological signaling molecule in the last decade. During the growth of this field, significant controversy has arisen centered on the physiological concentrations of H₂S. Recently, a monobromobimane (mBB) method has been developed for the quantification of different biologically-relevant sulfide pools. Based on the prevalence of the mBB method for sulfide quantification, we expand on this method to report the use of dibromobimane (dBB) for sulfide quantification. Reaction of H₂S with dBB results in formation of highly-fluorescent bimane thioether (BTE), which is readily quantifiable by HPLC. Additionally, the reaction of sulfide with dBB to form BTE is significantly faster than the reaction of sulfide with mBB to form sulfide dibimane. Using the dBB method, BTE levels as low as 0.6 pM can be detected. Upon use of the dBB method in wild-type and CSE^–/– mice, however, dBB reports significantly higher sulfide levels than those measured using mBB. Further investigation revealed that dBB is able to extract sulfur from other sulfhydryl sources including thiols. Based on mechanistic studies, we demonstrate that dBB extracts sulfur from thiols with α- or β-hydrogens, thus leading to higher BTE formation than from sulfide alone. Taken together, the dBB method is a highly sensitive method for H₂S but is not compatible for use in studies in which other thiols are present.     

Ruthenium-caged antisense morpholinos for regulating gene expression in zebrafish embryos

Photochemical approaches afford high spatiotemporal control over molecular structure and function, for broad applications in materials and biological science. Here, we present the first example of a visible light responsive ruthenium-based photolinker, Ru(bipyridine)₂(3-ethynylpyridine)₂ (RuBEP), which was reacted stoichiometrically with a 25mer DNA or morpholino (MO) oligonucleotide functionalized with 3′ and 5′ terminal azides, via Cu(i)-mediated [3+2] Huisgen cycloaddition reactions. RuBEP-caged circular morpholinos (Ru-MOs) targeting two early developmental zebrafish genes, chordin and notail, were synthesized and tested in vivo. One-cell-stage zebrafish embryos microinjected with Ru-MO and incubated in the dark for 24 h developed normally, consistent with caging, whereas irradiation at 450 nm dissociated one 3-ethynylpyridine ligand (Φ = 0.33) and uncaged the MO to achieve gene knockdown. As demonstrated, Ru photolinkers provide a versatile method for controlling structure and function of biopolymers.     

Sorting out the value of spectroscopic tools to assess the Colletotrichum acutatum impact in olive cultivars with different susceptibilities

The olive tree (Olea europaea L.) can be affected by Colletotrichum acutatum, causing a loss of yield and quality of the final products, whilst the incidence of this fungal infection depends on several factors, including cultivar susceptibility. Thus, the effect of C. acutatum infection in cultivars displaying different susceptibilities to this fungal disease (‘Galega Vulgar’ ‐ susceptible, ‘Cobrançosa’ ‐ moderately susceptible, ‘Picual’ ‐ tolerant) has been assessed through spectrophotometric methods and HPLC, while the FTIR spectra of the cuticles have been concomitantly registered, resorting to the ATR accessory. With the support of multivariate analysis, these spectra allowed to discriminate olives with distinct infection times, besides retrieving evidences concerning the different susceptibility of each cultivar, while these observations were reinforced by the spectrophotometric and chromatographic methods. Furthermore, the assessment of the phenolic profile evidenced individual compounds in the distinct cultivars, so as their variations in response to the fungal infection.     

Green and Catalyst-Free Synthesis of Some New Benzo[4,5]imidazo[1,2-a]pyrimidine Derivatives as Antimicrobial and Antitubercular Agents

Russian Journal of Organic Chemistry - A new series of 4-(1H-imidazol-4-yl)-2-(substituted phenyl)-1,4-dihydrobenzo[4,5]imidazo[1,2-a]­pyrimidines have been synthesized via a one-pot reaction...     

Synthesis and study of thioglycoside conjugates of 4-chloro-1,2-dithiol-3-one as potential cancer-preventive substances in vitro and in vivo

Russian Chemical Bulletin - Nucleophilic substitution of the chlorine atom in 4,5-dichloro-1,2-dithiol-3-one using 1-thio-β-d-glucopyranose and its 2,3,4,6-tetra-O-acetyl derivative in...     

Acid-Base Properties of 6-Methyluracil-5-carbonitrile and Its N-Methyl Derivatives

Russian Journal of General Chemistry - The constants of acid-base equilibrium of 6-methyluracil-5-carbonitrile in water were determined spectrophotometrically. For the first time,...     

Synthesis and Molecular Structure of 3-[N-Acetyl(3,5-dimethylphenyl)amino]-5,7-di(tert-butyl)-2-{5,8-dimethyl-4-[(3,5-dimethylphenyl)amino]quinolin-2-yl}tropone

Russian Journal of General Chemistry - Acylation of 5,7-di(tert-butyl)-2-{5,8-dimethyl-4-[(3,5-dimethylphenyl)amino]quinolin-2-yl}-3-[(3,5-dimethylphenyl)amino]tropone leads to...     

Zinc(II) Complexes with Azomethines of 2,4,6-Trimethylaniline and Halogen-Substituted Salicylaldehyde

Russian Journal of General Chemistry - Azomethines were synthesized from 2,4,6-trimethylaniline, salicylaldehyde, and its 3(5)-halogen derivatives, as well as their complexes with zinc(II) (ZnL2)....     

Chromophores with quinoxaline core in π-bridge and aniline or carbazole donor moiety: synthesis and comparison of their linear and nonlinear optical properties

Russian Chemical Bulletin - Two new D—π—A chromophores with the tricyanofuranyl acceptor (A), an amphi-divinyl quinoxaline π-electron conjugated bridge, and the carbazole or...