Leigh Syndrome: Spectrum of Molecular Defects and Clinical Features in Russia.

Leigh syndrome (LS), also known as infantile subacute necrotizing encephalopathy, is the most frequent mitochondrial disorder in children. Recently, more than 80 genes have been associated with LS, which greatly complicates the diagnosis. In this article, we present clinical and molecular findings of 219 patients with LS and give the detailed description of three cases with rare findings in nuclear genes MORC2, NARS2 and VPS13D, demonstrating wide genetic heterogeneity of this mitochondrial disease. The most common cause of LS in Russian patients are pathogenic variants in the SURF1 gene (44.3% of patients). The most frequent pathogenic variant is c.845_846delCT (66.0% of mutant alleles; 128/192), which is also widespread in Eastern Europe. Five main LS genes, SURF1, SCO2, MT-ATP6, MT-ND5 and PDHA1, account for 70% of all LS cases in the Russian Federation. Using next generation sequencing (NGS) technique, we were able to detect pathogenic variants in other nuclear genes: NDUFV1, NDUFS2, NDUFS8, NDUFAF5, NDUFAF6, NDUFA10, SUCLG1, GFM2, COX10, PMPCB, NARS2, PDHB and SLC19A3, including two genes previously associated with Leigh-like phenotypes-MORC2 and VPS13D. We found 49 previously undescribed nucleotide variants, including two deep intronic variants which affect splicing.

Schmidtinus annapurnensis, a new genus and species of Batrisitae from Nepal (Coleoptera: Staphylinidae: Pselaphinae).

Schmidtinus annapurnensis Yin Kurbatov gen. et sp. nov. of the pselaphine tribe Batrisini is described from the Annapurna mountains of Nepal, with the habitus and major diagnostic features illustrated. The morphological features that distinguish Schmidtinus gen. nov. from related batrisine genera are discussed.

A new species of the genus Dendrolasiophilus Nomura, 2010 from the south of the Russian Far East (Coleoptera, Staphylinidae, Pselaphinae).

Dendrolasiophilus subitus sp. nov. from the Russian Far East is described and illustrated. Some nomenclatural notes on the genus Dendrolasiophilus Nomura, 2010 are given.

Mechanisms of nitric oxide generation in living systems.

In modern chemical and biochemical studies, special attention is paid to molecular systems capable of generating nitric oxide (NO), which is one of the most important signalling molecules in the body and can trigger a whole cascade of reactions. Despite the importance of this molecule, the mechanisms of its formation in living organisms remain a subject of debate. This review combines the most important methods of releasing NO from endogenous and exogenous sources. The history of endogenous NO donors dates back more than 150 years, since the synthesis of nitroglycerin, which remains the standard vasodilator today, even though it is known that it and many other similar compounds lead to the development of a nitrate tolerance. Particular awareness is devoted to the mechanisms of NO formation without the participation of enzymes, since these methods are most important for creating exogenous sources of NO as drugs. The study of NO formation methods is centred on both the creation of new NO donors and understanding the mechanisms of tolerance to them.

Lithium-Promoted Cycloaddition of Indole-2,3-dienolates and Carbon Disulfide as a One-Pot Route to Thiopyrano[4,3-b]indole-3(5H)-thiones.

A new approach for the annulation of a thiopyrane ring to an indole core under mild conditions was developed. Treating 2-methyl-3-acylindoles with lithium diisopropyl amide leads to the elimination of a proton from the 2-methyl group. The lithium indole-2,3-dienolates obtained were found to react with CS2 to give the corresponding thiopyrano[4,3-b]indole-3(5H)-thiones. The mechanism represents a stepwise addition through ion-pair formation, according to PCM/B3LYP/6-311++G**, PBE1PBE/6-311++G**, and MP2//HF/6-311++G** quantum chemical calculations. AIM calculations revealed the essential role of the Li atom at all stages of the process.

Magnetic resonance imaging pattern variability in dysferlinopathy.

The widespread use of magnetic resonance imaging (MRI) in the diagnosis of myopathies has made it possible to clarify the typical MRI pattern of dysferlinopathy. However, sufficient attention has not been given to the variability of MRI patterns in dysferlinopathy. MATERIALS AND METHODS: Twenty-five patients with the clinical manifestations of dysferlinopathy were examined. For all patients, creatine phosphokinase levels were measured and molecular genetics were examined. In two patients, immunohistochemical examinations of muscle biopsies were performed. MRI scanning was included T2 multi-slice multi-echo, T1 weighted, T2 weighted and Short Tau Inversion Recovery T2 weighted sequences. Quantitative and semi-quantitative evaluations of fatty replacement and swelling of the muscles were undertaken. RESULTS: Variability in the MRI patterns was lowest in the pelvis and leg muscles and highest in the thigh muscles. Three main types of MRI patterns were distinguished: posterior-dominant (80%), anterior-dominant (16%), and diffuse (4%). Among patients with the anterior-dominant pattern, the collagen-like variant (4%), proximal variant (4%) and pseudo-myositis (8%) were separately distinguished. CONCLUSIONS: Awareness of atypical MRI patterns in dysferlinopathy is important for increasing the efficiency of routine diagnostics and optimizing the search for causative gene mutations.

A new species of Faronus Aubé, 1844, endemic to Malta (Coleoptera, Staphylinidae, Pselaphinae).

Faronus rica sp. nov. endemic to Malta is described and illustrated, and placed in the Faronus hispanus species group. Faronus rica sp. nov. is closely related to F. siculus Fiori, 1913, an endemic species to Sicily, and they can be distinguished based on morphological features highlighted in the present work.

Notes on Iniocyphus iheringi Raffray, 1912 (Coleoptera: Staphylinidae: Pselaphinae).

The only available specimen of Iniocyphus iheringi Raffray, 1912, type species of the type genus of the tribe Iniocyphini Inyocyphus Raffray, 1912, is redescribed and illustrated in detail. The original spelling of the species epithet iheringi is reinstated over jheringi, which was an incorrect subsequent spelling. The specimen examined is designate as the lectotype.

From 3-Acyl-2-methylindoles to γ-Carbolines: Li-Promoted Cycloaddition Reaction and Its Quantum Chemical Study.

A one-pot cycloaddition strategy for obtaining γ-carbolines under mild conditions was developed. The reaction represents a new approach to the annulation of a pyridine ring to an indole core. Treating 2-methyl-3-benzoylindoles with lithium diisopropyl amide leads to the elimination of a proton from the 2-methyl group. The organolithium compounds generated were found to react with nitriles. The resulting 4,5-dihydro-1H-pyrido[4,3-b]indol-1-ols undergo spontaneous water elimination to give the corresponding γ-carbolines. The applicability of this reaction for the synthesis of isoquinolines has been shown. For the first time, a lithium atom was found to be part of an eight-centered polycyclic transition state according to a detailed DFT PCM/DFT/B3LYP/6-311++G(d,p) and ab initio PCM/MP2//HF/6-311++G(d,p) quantum chemical study.

Comprehensive study of nitrofuroxanoquinolines. New perspective donors of NO molecules.

The goal of present work is the study of NO releasing mechanisms in nitrofuroxanoquinoline (NFQ) derivatives. Mechanisms of their structural non-rigidity and pathways of NO donation - spontaneous or under the action of sulfanyl radicals or photoirradiation - were considered in details, both experimentally and quantum chemically. Furoxan-containing systems of the discussed type are not capable of spontaneous or photoinduced decomposition under mild conditions, and sulfanyl (radical) induced processes are the most preferable. It was shown that appropriate modification of NFQ through [3 + 2] cycloaddition and subsequent aromatization is a powerful tool to design new prospective donors of NO molecule. Two newly obtained NFQ derivatives were proven to have unusually high NO activity in full accordance with the theoretical model. We hope that these examples will encourage community to seek for new NO active molecules among cycloadducts and modified furoxanes.

Non-canonical DNA structures: Comparative quantum mechanical study.

A study of relative thermodynamic stability of non-canonical DNA structures (triplexes, G-quadruplexes, i-motifs) for the first time was conducted on the basis of quantum chemical DFT/B3LYP/6-31++G (d) calculations. Results of the calculations completely reproduce the experimental data on stability of G-quadruplexes comparatively Watson-Crick B-DNA. It was discovered that combinations of non-canonical DNA structures were energetically more favorable than separated nitrogenous bases. Supramolecular complexes of the non-canonical DNA structures (NSs) can be considered as a biological drug targets in gene regulation (for example in tumor therapy), in contrast to previous works, where NSs were studied independently.

Thiol-induced nitric oxide donation mechanisms in substituted dinitrobenzofuroxans.

The goal of present work is the quantum chemical study of NO donation mechanism in dinitrobenzofuroxan aryl derivative. Mechanisms of its structural non-rigidity (1,3-N-oxidic and Boulton-Katritzky rearrangements) and minimum energy pathways of NO donation under the action of sulfanyl radical SH· were considered in details. DFT calculations were performed using B3LYP and UB3LYP functionals in the 6-311++G(d,p) basis set. Obtained results showed that a high experimentally proven NO-donor activity of dinitrobenzofuroxan aryl derivative is connected with its existence in the form of mixture of 1-N-oxide and 3-N-oxide, where the 3-N-oxide is more reactive towards SH·. The thiol-induced low-barrier mechanism of NO-donation is a result of para-aminophenyl substituent availability in position 7 of dinitrobenzofuroxan.

Revision of Neodeuterus Schaufuss and description of a new allied genus from Borneo (Coleoptera: Staphylinidae: Pselaphinae).

The Sumatran genus Neodeuterus is revised, and the two included species are synonymized (i.e., N. admirandus = N. alter syn. n.). In addition, Borneodeuterus gen. n. is erected to accommodate B. sannio sp. n. from Borneo.

The stepwise Diels-Alder reaction of 4-nitrobenzodifuroxan with Danishefsky's diene.

The Diels-Alder reaction of 4-nitrobenzodifuroxan (NBDF) with 1-methoxy-3-trimethylsilyloxy-1,3-butadiene has been investigated experimentally and theoretically. Treatment of NBDF with excess diene in chloroform at room temperature was found to afford a single product that contained a carbonyl functionality. Based on an X-ray structure and NMR spectroscopic data, the product appeared to be a result of the hydrolysis of the OSiMe(3) moiety of the thermodynamically more stable endo [2+4] cycloadduct, characterized by a cis arrangement of the MeO and NO(2) functionalities. In situ NMR investigations of the interaction were carried out at room temperature in CDCl(3) and at -40 °C in deuterated acetonitrile. Calculations at the B3LYP/6-31G* level in the gas phase and in acetonitrile were carried out under the assumption that the most stable cis conformation of the diene is also the most reactive in the interaction. The analysis revealed the NBDF/cis diene interaction involves the formation of a zwitterionic intermediate. Importantly, this intermediate is formed in two preferred conformations, which correspond to the endo and exo modes of approach of the reagents. Cyclization of these two identified conformations afforded the experimentally characterized endo and exo [2+4] cycloadducts. According to the calculations, the interconversion of the two conformers can either take place through a return to the pre-reaction complexes or it can occur by rotation through an intermediate conformation of lesser stability. In view of the stepwise character of the interaction, the possibility that the intermediate zwitterion is the result of the interaction between NBDF and the trans diene could not be excluded. Calculations carried out with the most stable and more populated s-trans conformer confirmed this idea and supported the role of the zwitterion in the overall interaction.

Superelectrophilicity of the nitroolefinic fragment of 4-nitrobenzodifuroxan in Michael-type reactions with indoles: a kinetic study in acetonitrile.

The kinetics of the coupling of 4-nitrobenzodifuroxan (NBDF) with a series of indoles 8 a-e to give the expected Michael-type adducts 9 a-e have been investigated in acetonitrile solution. No significant influence of the nature of the isotopic substitution at C-3 of the indole ring has been found, indicating that the NBDF addition step is the rate limiting step of the SEAr substitution of the indole moiety. This implies that the measured second-order rate constants (k) for the reactions are identical to the second order rate constants (k1NBDF) associated to the C--C coupling step. By using the known N and s parameters characterizing the nucleophilicity of indoles, the k1NBDF rate constants are found to fit nicely to the three parameters equation logk1=s(N+E) introduced by Mayr to describe the feasibility of nucleophilic-electrophilic combinations. Based on this, the electrophilicity parameter E of NBDF could be determined as E=-6.15. This corresponds to a positioning of the reactivity of the nitroactivated double bond of NBDF in the domain of superelectrophilicity previously defined for nitrobenzofuroxans, in accord with the finding that the rates of coupling of 8 a-e with NBDF are only one order of magnitude lower than those for the coupling of these indoles with 4,6-dinitrobenzofuroxan (DNBF). The theoretical scale of electrophilicity introduced by Domingo et al. on the basis of the global electrophilicity index omega defined by Parr is also a very useful tool to discuss the relative reactivities of NBDF, DNBF, and a number of differently activated C==C double bonds.

Ring opening and ring closure in an indolizine structure activated through S(N)Ar coupling with superelectrophilic 4,6-dinitrobenzofuroxan, an unusual intramolecular oxygen transfer from a N-oxide functionality.

Coupling of superelectrophilic 4,6-dinitrobenzofuroxan with a pi-excessive indolizine structure affords a strongly dipolar substitution product which undergoes a facile but unusual rearrangement induced by an intramolecular oxygen atom transfer from the N-oxide functionality of the DNBF moiety.

N-[2-[(3,5-di-tert-butyl-4-oxocyclohexa-2,5-dien-1-ylidene)amino]phenyl]-N-(5,7-dinitroquinolin-8-yl)-1-phenylmethanesulfonamide: the nature of intramolecular shortened contacts.

The title compound, C(36)H(35)N(5)O(7)S, is found to exist in a non-spirocyclic (ring-opened) form in the crystal, although equilibrium of ring-opened and ring-closed forms (or so-called ring-chain isomerization) is possible in solution. The 4-oxocyclohexa-2,5-diene ring has a flattened sofa conformation. The N.C intramolecular separation of the atoms which would be directly bonded in a ring-closed form is quite short [2.813 (5) A]. Topological analysis of charge density based on density-functional-theory calculations was used for consideration of shortened intramolecular contacts and indicates a strong attractive bonding interaction between these N and C atoms in the crystal structure.

Superelectrophilic heterocycles: facile S(N)Ar-S(E)Ar couplings involving very weak carbon nucleophiles.

Superelectrophilic halonitro-2,1,3-benzoxadiazoles undergo remarkably facile carbon-carbon couplings with some electron-rich aromatics and heteroaromatics, affording quantitatively products exhibiting an intense visible absorption due to strong intramolecular charge transfer.