Identification and Pathogenicity of Fusarium Species Associated with Onion Basal Rot in the Moscow Region of Russian Federation.

Fusarium basal rot of onions causes large losses during storage of commercial production of onion bulbs, which in turn adversely affects the food market situation in the off-season period. There are no data on the composition of Fusarium spp., which causes onion basal rot in the Russian Federation. Therefore, our research was aimed at Fusarium spp. causing onion basal rot in the Moscow Region of the Russian Federation and studying the pathogenicity of these species for the host plant. We studied 20 isolates of Fusarium spp. collected from affected mature bulbs and seed bulbs. Species identification of the isolates was carried out using analysis of the nucleotide sequences of the three genetic loci ITS, tef1 and rpb2, as well as was based on the macro- and micromorphological characteristics of these isolates. As a result, the species F. annulatum (F. fujikuroi species complex), F. oxysporum (F. oxysporum species complex), F. acuminatum (F. tricinctum species complex) and F. solani (F. solani species complex) were identified to involve in the pathogenesis of Fusarium basal rot. We have shown for the first time that the species F. annulatum and F. acuminatum are highly aggressive and capable of causing onion basal rot. The predominant species were F. annulatum and F. oxysporum. The proportion of these species in the total number of analyzed isolates was 60% and 25%, respectively. The largest proportion (33%) of highly aggressive on mature bulbs isolates was found in the species F. annulatum. The data obtained provide practical insights for developing strategies to manage Fusarium fungi responsible for onion basal rot Moscow Region of the Russian Federation. In addition, data about species composition and aggressive isolates may be used in onion breeding for resistance to Fusarium basal rot.

Fusarium Species Causing Pepper Wilt in Russia: Molecular Identification and Pathogenicity.

Fusarium wilt pathogens represent an ongoing threat to pepper production worldwide. This is the first report providing data on the molecular identification of Fusarium fungi that cause wilt in pepper in the southern regions of Russia. Monitoring of the Fusarium infection on pepper was carried out in 2019-2022 in two economically important regions of this culture production: the Krasnodar Krai and Crimea. Based on a phylogenetic analysis of the translation elongation factor (EF1a) and the internal transcribed spacer (ITS), as well as the macro- and micromorphological characteristics of the fungi, the causative agents of Fusarium wilt have been identified. The causative agents identified as representatives of the Fusarium species composition included: F. clavus, F. solani, F. oxysporum, F. verticillioides, F. commune, F. torulosum, and F. sporotrichioides. Depending on the region, the specifics of biodiversity and the ratio of these species in pathocomplexes were noted. In Crimea, wilting could be attributed to all of the identified species; in the Krasnodar Krai, F. verticillioides and F. clavus were found to contribute to wilting. The pathogenicity test showed that the pathogens of pepper wilting in Russia, in addition to the already known F. oxysporum and F. solani, are the species F. clavus and F. verticillioides. This is the first report on the ability of these species to cause Fusarium wilt in pepper cultures. The obtained data will be of practical value for the development of biological control measures for fungi of the genus Fusarium, which cause pepper wilt in areas of industrial production and seed production. In addition, data on species composition and aggressive isolates will be used in a pepper breeding program for resistance to Fusarium wilt.

Sulfur-mediated synthesis of unsymmetrically substituted N-aryl oxalamides by the cascade thioamidation/cyclocondensation and hydrolysis reaction.

A facile and straightforward synthesis of unsymmetrically substituted N-aryl oxalamides from 2,2'-biphenyldiamines, 2-chloroacetic acid derivatives, elemental sulfur, and water has been developed. This protocol is distinguished by efficiency in water under metal-free conditions for N-aryl oxalamides bearing a side-chain NH2-group; it can be adapted for scale-up synthesis. The scope and limitations of this transformation have been investigated.

Development of 1,3-thiazole analogues of imidazopyridines as potent positive allosteric modulators of GABAA receptors.

Structure-activity relationship studies were conducted in the search for 1,3-thiazole isosteric analogs of imidazopyridine drugs (Zolpidem, Alpidem). Three series of novel γ-aminobutyric acid receptor (GABAAR) ligands belonging to imidazo[2,1-b]thiazoles, imidazo[2,1-b][1,3,4]thiadiazoles, and benzo[d]imidazo[2,1-b]thiazoles were synthesized and characterized as active agents against GABAAR benzodiazepine-binding site. In each of these series, potent compounds were discovered using a radioligand competition binding assay. The functional properties of highest-affinity compounds 28 and 37 as GABAAR positive allosteric modulators (PAMs) were determined by electrophysiological measurements. In vivo studies on zebrafish demonstrated their potential for the further development of anxiolytics. Using the OECD "Fish, Acute Toxicity Test" active compounds were found safe and non-toxic. Structural bases for activity of benzo[d]imidazo[2,1-b]thiazoles were proposed using molecular docking studies. The isosteric replacement of the pyridine nuclei by 1,3-thiazole, 1,3,4-thiadiazole, or 1,3-benzothiazole in the ring-fused imidazole class of GABAAR PAMs was shown to be promising for the development of novel hypnotics, anxiolytics, anticonvulsants, and sedatives drug-candidates.

Synthesis of Dibenzo[d,f][1,3]Diazepines via Elemental Sulfur-Mediated Cyclocondensation of 2,2'-Biphenyldiamines with 2-Chloroacetic Acid Derivatives.

The three-component reaction of 2,2'-biphenyldiamines with 2-chloroacetic acid derivatives and elemental sulfur was developed for the practical synthesis of unknown 2-carboxamide-substituted dibenzo[d,f][1,3]diazepines. This protocol is distinguished by efficiency in water and good tolerance to functional groups and can be adapted to a large-scale synthesis. The chemoselective preparation of a variety of 2-S,N,O-substituted dibenzo[d,f][1,3]diazepines was accomplished using the developed method.

Complex action of tyramine, tryptamine and histamine on native and recombinant ASICs.

Proton-gated channels of the ASIC family are widely distributed in the mammalian brain, and, according to the recent data, participate in synaptic transmission. However, ASIC-mediated currents are small, and special efforts are required to detect them. This prompts the search for endogenous ASIC ligands, which can activate or potentiate these channels. A recent finding of the potentiating action of histamine on recombinant homomeric ASIC1a has directed attention to amine-containing compounds. In the present study, we have analyzed the action of histamine, tyramine, and tryptamine on native and recombinant ASICs. None of the compounds caused potentiation of native ASICs in hippocampal interneurons. Furthermore, when applied simultaneously with channel activation, they produced voltage-dependent inhibition. Experiments on recombinant ASIC1a and ASIC2a allowed for an interpretation of these findings. Histamine and tyramine were found to be inactive on the ASIC2a, while tryptamine demonstrated weak inhibition. However, they induce both voltage-dependent inhibition of open channels and voltage-independent potentiation of closed/desensitized channels on the ASIC1a. We suggest that the presence of an ASIC2a subunit in heteromeric native ASICs prevents potentiation but not inhibition. As a result, the inhibitory action of histamine, which is masked by a strong potentiating effect on the ASIC1a homomers, becomes pronounced in experiments with native ASICs.

Synthesis of Imidazo[2,1-b]thiazoles via Copper-Catalyzed A3-Coupling in Batch and Continuous Flow.

A straightforward method for the synthesis of functionalized imidazo[2,1-b]thiazoles starting from benzaldehydes, 2-aminothiazoles, and alkynes under copper(I,II) catalysis was developed. The protocol allows the construction of a variety of aryl-substituted imidazo[2,1-b]benzothiazoles, -[2,1-b]thiazoles, and -[2,1-b][1,3,4]thiadiazoles. The reactions were easy to perform affording most of the desired products in 33-93% yields. The intensification of the process in a continuous-flow reactor increases the products' yields up to quantitative.

Common binding site for externally and internally applied AMPA receptor channel blockers.

Adamantane derivative IEM-1676 (Ad-N(+)H(2)-(CH(2))(5)-N(+)Me(3)) causes open-channel block of Ca(2+)-permeable AMPA receptors when applied externally, but internal application results in both closed- and open-channel block. The relationships between blocking action of externally and internally applied IEM-1676 were studied using patch clamp technique. Extracellular action of IEM-1676 was decreased by its intracellular application, thus suggesting that the binding sites of the externally and internally applied drug coincide or at least overlap significantly. We demonstrated that internal closed-channel block is voltage-dependent and occurs at the region where the externally applied drug is trapped. We conclude that the selectivity filter of the closed AMPA receptor channel is not occluded and remains permeable for organic cations.