The adaptation of the N. crassa lipoxygenase (LOX) in response to heat (45°C) and cold (4°C) shock was studied. The difference was revealed in the dynamics of the LOX activity depending on the growing conditions of the mycelium. After incubation of the surface culture at 45°C, a gradual increase in the specific activity of the enzyme was observed with maximum at 2–3 h, followed by a subsequent decrease to the initial level. Under the same conditions, in a submerged culture, a decrease in the LOX activity was observed after 5 min; however, after 1 h of incubation, the enzyme activity also reached the initial level. The sensitivity of the N. crassa LOX to elevated temperatures is very high, since it is noted only in a narrow temperature range: the effect was detected at 45oC; however, the enzymatic activity did not change in the culture incubated at 42°C, but, on the other hand, LOX was completely inactivated in the mycelium at 48°C. When the fungal cells were exposed to cold, the specific LOX activity increased after 1 h, then decreased to the initial level (2–3 h) and increased again, reaching a maximum after 18 h. When two stress factors, cold and starvation, acted simultaneously on the N. crassa cells, the treatment with cold had a decisive effect on the LOX activity, which was especially noticeable after 8 h of incubation.

This review presents recent data about various types of antifungal surfaces (nanostructured, functionalized, and with modified wettability) used in medicine, the food industry, and other areas. Particular attention is paid to the functionalization of surfaces with fungicides such as amphotericin B, anidulafungin, fluconazole, ziram and caspofungin, as well as the development of biodegradable edible films based on chitosan, hydroxypropyl methylcellulose, and alginate containing nontoxic antifungal compounds.

The review summarizes the latest data on the identification and synthesis of nitric oxide in fungi, as well as the mechanisms of NO action in these organisms, including S-nitrosylation and the nitration of amino acid residues, the initiation of DNA breaks, transcriptional gene activation, and the cGMP-dependent signaling pathway. Particular attention is paid to the NO-dependent regulation of such processes as apoptosis and various stress responses, spore germination, mycelium growth, and fungal differentiation.

Nitric-oxide synthase activity was detected in Neurospora crassa cells with the measurement of the conversion of 3H-L-arginine to 3H-L-citrulline. Some characteristics of this activity (sensitivity to calcium ions, action of specific enzyme inhibitors, and western blot analysis) were similar to those of an inducible enzyme found in mammals. According to western blotting, the molecular weight of NO synthase was around 130 kDa. No light-dependent changes in the specific activity of NO synthase were revealed in the photocarotenogenesis and photoconidiation of N. сrassa.

The role of nitric oxide in the photomorphogenesis of several Neurospora сrassa strains (the wild-type strain wt-987, the nit-2 mutant, which lacks nitrite and nitrate reductase, and the nit-6 mutant, which lacks nitrite reductase) was evaluated from the content of nitrate and nitrite, the final products of NO decomposition, in the mycelium and cultivation medium. Analysis of the dynamics of nitrite release from the mycelium of the N. crassanit-6 strain in the course of photostimulated conidiogenesis indicated the possible participation of the NO-generating mechanism in the fungal photosignal transduction. Light-regulated conidiation in N. crassa was inhibited by the introduction of S-nitrosoglutathione, a nitrogen oxide donor, to the cultivation medium, and stimulated by the introduction of L-nitroarginine, an inhibitor of NO synthase, which is inderect indicative of the role of NO in the process. However, the absence of $${\text{NO}}_{2}^{ - }$$ release during the photostimulated development of the protoperithecia (precursors of the female sexual structures) indicated a low probability of NO participation in sexual propagation of the fungus.

Comparative analysis of the influence of arachidonic acid and its derivatives, 3-hydroxy-(5Z,8Z,11Z,14Z)-eicosatetraenoic and 20-hydroxy-(5Z,8Z,11Z,14Z)-eicosatetraenoic acids, on the formation of sexual and asexual reproductive structures in Neurospora crassa demonstrated that the presence and location of the hydroxyl group in unsaturated fatty acid determine the biological effect of the compound. In the presence of 5 μM of arachidonic acid, 20-HETE, and 3-HETE, vegetative spore formation in the light decreased by 45, 31, and 40%, respectively, indicating a similarity in the mechanisms of their action on the light-dependent asexual reproduction of the fungus. However, the effects of these compounds on the sexual process of N. crassa were radically different. Gas chromatography–mass spectrometry (GC–MS) revealed a fourfold increase in the monounsaturated oleic acid content in N. crassa cells after the addition of arachidonic acid. In the same time, the effect was not observed after the addition of 20-HETE. On the other hand, the increase in the linoleic acid content in the fungal mycelia was higher with 20-HETE.

Oxylipins are a family of oxygenated fatty acids that are very diverse with regard to origin, structure, and functions. These compounds are found in almost all living beings and serve both as autoregulators of the development of organisms and as communication molecules. The autoregulatory role of oxylipins in fungi is to control the development, reproduction, synthesis of secondary metabolites (including mycotoxins), and adaptive responses. The role of oxylipins in the regulation of pathogenesis accounts for an important aspect of research on the biological activity of these compounds. The synthetic pathways and functions of oxylipins of fungi, the differences between fungal oxylipins and oxylipins from bacteria, higher plants, and mammals, and the role of oxylipins in the interaction of fungi with other organisms are considered in the present review.

The regulatory effect of two oxyderivatives of unsaturated fatty acids (oxylipins), 18-hydroxy(9Z,12Z)-octadecadienoic acid (18-HODE) and 18-(9Z,12Z,15Z)-octadecatrienoic acid (18-HOTrE), on the sexual and asexual sporulation of wild-type Neurospora crassa strains and wc-1 and wc-2 mutants was studied. In the wild-type strain, 18-HODE, unlike 18-HOTrE, stimulated protoperithecia formation in the dark and in the light. In the same strain, the studied oxylipins influenced conidiogenesis only under illumination. 18-HODE stimulated and 18-HOTrE inhibited the conidia formation. Oxylipins had no effect on protoperithecia formation in photoreceptor complex mutants, which apparently indicated its involvement in signal transduction in N. crassa. The stimulating action of the studied oxylipins on conidiagenesis in wc-1 and the lack of action in wc-2 may indicate alternative signaling pathways of oxylipins in this process.

We performed a quantitative assessment of the conidia yield in Neurospora crassa in response to treatment with different conidiation effectors. Depending on nitrogen source and intactness of nitrite reducetase (NiR) and nitrate reductase (NR), light and dehydration affected the number of viable conidia produced by the ascomycete. In most variants of the nitrogen status, the combined action of light and dehydration synergistically increased the conidia yield. Conidiation in wild-type cells cultivated on the medium with NH4Cl as a sole nitrogen source did not respond to light, whereas illumination of the same culture grown on NH4NO3- or NaNO3-containing medium stimulated the process of spore formation. In response to light exposure, conidia formation occurred in the same way in the nit-2 (no NR and NiR) and nit-6 (no NiR) mutants cultivated in the presence of NH4Cl, but differed greatly when grown on the medium with NH4NO3. The results obtained indicate the possibility that NR and NiR participate in the photoconidiation regulation (wild-type strain on the medium with secondary nitrogen source); however, they cannot be necessary because light-dependent stimulation of spore formation was observed in nit-2 and nit-6 mutants.

Исследовано регуляторное действие двух оксипроизводных ненасыщенных жирных кислот (оксилипинов) – 18-гидрокси-(9Z,12Z)-октадекадиеновой кислоты (18-HODE) и 18-гидрокси-(9Z,12Z,15Z)-октадекатриеновой кислоты (18-HOTrE), на половое и бесполое размножение штаммов Neurospora crassa дикого типа и мутантов wc-1 и wc-2. Показано, что у штамма дикого типа 18-НОDE, в отличие от 18-HOTrE, является стимулятором образования протоперитециев в темноте и на свету. У этого же штамма исследованные оксилипины оказывали влияние на конидиогенез только в условиях освещения: 18-HODE стимулировала, а 18-HOTrE ингибировала образование конидий. Оксилипины не влияли на образование протоперитециев у мутантов по фоторецепторному комплексу, что, по-видимому, свидетельствовало о его участии в передаче сигнала у N. crassa. Стимуляция образования конидий у wc-1 под влиянием исследованных оксилипинов и отсутствие их действия на wc-2 может указывать на наличие альтернативных путей передачи сигнала оксилипинов при конидиогенезе.

The effect of the natural oxylipins 3( R )-hydroxy-(5 Z ,8 Z ,11 Z ,14 Z )-eicosatetraenoic acid (3-HETE) and 18-hydroxy-(9 Z ,12 Z )-octadecadienoic acids (18-HODE) on the growth and hypha aggregation, as well as on some light-depending processes, such as carotenoid biosynthesis, protoperithecia formation (sexual cycle), and conidiation (asexual cycle), of the ascomycete Neurospora crassa was studied. Hypha aggregation and growth slowdown were induced by 3-HETE, 18-HODE, and linoleic acid. At concentrations from 5 to 50 μM, these compounds had no significant effect on the light-induced carotenogenesis. At the same time, these 3-HETE and 18-HODE concentrations, unlike linoleic acid, induced the formation of protoperithecia in the dark. At the concentration of 5 μM, an additive effect of oxylipins and light was revealed. The studied oxylipins had different effects on the asexual reproduction of N. crassa : 3-HETE induced conidiation in the dark, whereas 18-HODE induced conidiation in the light. The possible involvement of oxylipins in the regulation of the processes of sexual and asexual reproduction of N. crassa is discussed.

Исследовали влияние оксилипинов природной структуры, 3(R)-гидрокси-(5Z,8Z,11Z,14Z)-эйкозатетраеновой кислоты (3-HETE) и 18-гидрокси-(9Z,12Z)-октадекадиеновой кислоты (18-HODE), на рост и агрегацию гиф, а также на ряд светозависимых процессов – биосинтез каротиноидов и образование протоперитециев (половой цикл) и конидий (бесполый цикл) – у аскомицета Neurospora crassa. 3-HETE, 18-HODE и линолевая кислота вызывали агрегацию гиф и замедление их роста. При концентрациях от 5 до 50 мкМ данные соединения не оказывали существенного влияния на индуцируемое светом образование каротиноидов. Вместе с тем, в этом же диапазоне концентраций 3-HETE и 18-HODE, в отличие от линолевой кислоты, вызывали увеличение образования протоперитециев в темноте. При концентрации 5 мкМ было выявлено аддитивное действие оксилипинов и света. Оксилипины по-разному влияли на бесполое размножение гриба – 3-HETE стимулировала образование конидий в темноте, а 18-HODE – на свету. Обсуждается участие оксилипинов в регуляции процессов полового и бесполого размножения N. crassa.