The recent progressive increase in the incidence of invasive fungal infections, especially in immunocompromised patients, makes the search for new therapies crucial in the face of the growing drug resistance of prevalent nosocomial yeast strains. The latest research focuses on the active compounds of natural origin, inhibiting fungal growth, and preventing the formation of fungal biofilms. Antimicrobial peptides are currently the subject of numerous studies concerning effective antifungal therapy. In the present study, the antifungal properties of two synthetic peptides (ΔM3, ΔM4) derived from an insect antimicrobial peptide – cecropin D – were investigated. The fungicidal activity of both compounds was demonstrated against the yeast forms of Candida albicans, Candida tropicalis, and Candida parapsilosis, reaching a MFC99.9 in the micromolar range, while Candida glabrata showed greater resistance to these peptides. The scanning electron microscopy revealed a destabilization of the yeast cell walls upon treatment with both peptides; however, their effectiveness was strongly modified by the presence of salt or plasma in the yeast environment. The transition of C. albicans cells from yeast to filamentous form, as well as the formation of biofilms, was effectively reduced by ΔM4. Mature biofilm viability was inhibited by a higher concentration of this peptide and was accompanied by increased ROS production, activation of the GPX3 and SOD5 genes, and finally, increased membrane permeability. Furthermore, both peptides showed a synergistic effect with caspofungin in inhibiting the metabolic activity of C. albicans cells, and an additive effect was also observed for the mixtures of peptides with amphotericin B. The results indicate the possible potential of the tested peptides in the prevention and treatment of candidiasis.

Herein, we describe the micro‐ and macro‐morphology of the olfactory organ in broad‐nosed pipefish (Syngnathus typhle) with a comparison of this organ between males and females during breeding season. With 8 adult males, 8 females, and 7 pregnant males collected during the breeding season from the Baltic sea as our samples, our research was conducted using light and electron (TEM, SEM) microscopes and immunohistochemistry methods to distinguish the olfactory sensory neurons. The interior of the olfactory chamber lacked an olfactory rosette. Instead, olfactory receptor epithelium covered the inner walls of the olfactory chamber and, to varying degrees, the inside of the anterior and posterior nostrils. All types of olfactory sensory neurons (ciliated, microvillus, and crypt) were present within the olfactory sensory epithelium, although the crypt sensory neurons were limited to the pregnant and non‐pregnant males). The olfactory sensory neurons were present in the areas where the density of the non‐sensory epithelium cells was reduced. No significant differences in morphology of the olfactory organ between sexes were found. Nevertheless, only in males crypt sensory neurons were presented in olfactory epithelium, which indicates that sense of smell could play a little role during mating.

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Osteoglossomorpha, an ancient Teleostei group, exhibits many ancestral structural features. Herein, we describe the diversity in morphology of olfactory organs of air-breathing Pantodon buchholzi, Arapaima gigas, and Gymnarchus niloticus in terms of adaptations to short ventures out of water and compare the results with the water-breathing Osteoglossum bicirrhosum. We demonstrate the presence of olfactory rosettes within the olfactory chamber in all studied species and additionally a peculiar cudgel-shaped structure in P. buchholzi. The typical olfactory rosette with centrally located elongate median raphe and two rows of olfactory lamellae was found only in P. buchholzi. In A. gigas, the olfactory lamellae arranged in semicircular manner were merged to small median raphe. Osteoglossum bicirrhosum and G. niloticus lacked median raphe, while the olfactory lamellae were ordered nearly parallel or circular, respectively. Olfactory epithelium lining the olfactory lamellae was unfolded only in P. buchholzi and G. niloticus. In contrast, in O. bicirrhosum and A. gigas convexities formed by nonsensory cells and concavities made by the sensory component were observed. Among the olfactory sensory neurons, ciliated and microvillus neurons were found in all studied species. Crypt-like cells were noted only in P. buchholzi, whereas rod-like cells were unique for A. gigas. The substantial morphological variation of the olfactory organ structure and ultrastructure in the studied osteoglossiforms may be explained by the early division of Osteoglossomorpha within Teleostei and long-term, independent evolution within the families.

Here, we describe the anatomy of the female reproductive system of the aquatic, viviparous caecilian Typhlonectes natans. We conducted our research on two adult females using light microscopy and reflected our results with the available literature data on the anatomy of the reproductive systems of caecilian amphibians. The female reproductive system of T. natans consisted of longitudinal, paired ovaries incorporated with fat bodies, paired oviducts and the cloaca. The ovaries were arranged in segmental mannered germinal nests and the oocytes were in various stages of development. Ovulated, postvitellogenic oocytes were present in the oviducts of both females. The wall of the oviduct consisted of three layers: the mucous membrane, layers of muscles and serous membrane. The presence of wedge-like cells, not previously reported in the mucous membrane of the caecilian oviduct is postulated. Although the females possessed ovulated eggs, no sperm were detected in any part of the oviducts leaving the question of eventual female sperm storage in Typhlonectes natans open.Anatomia żeńskiego układu rozrodczego oraz system przechowywania nasienia żyworodnego płaza beznogiego Typhlonectes natans (Gymnophiona: Typhlonectidae) Słowa kluczowe Typhlonectidae, płazy beznogie, układ rozrodczy, żyworodność, przechowywanie plemników StreszczenieW artykule opisano budowę anatomiczną żeńskiego układu rozrodczego żyworodnego płaza beznogiego Typhlonectes natans. Badania z wykorzystaniem mikroskopii świetlnej przeprowadzono na dwóch dojrzałych samicach. Otrzymane wyniki porównano z danymi literaturowymi dotyczącymi żeńskiego układu rozrodczego płazów beznogich. U T. nantans składa się on z wydłużonych, parzystych jajników oraz parzystych jajowodów uchodzących do kloaki. W pobliżu jajowodów znajdują się wydłużone ciała tłuszczowe. Segmentowane jajniki zawierają gniazda oogoniów oraz oocyty będące na różnych etapach oogenezy, natomiast w świetle jajowodów u obu samic stwierdzono owulujące oocyty. Ściana jajowodu składa się z trzech warstw: śluzowej, mięśniowej i surowiczej. W warstwie śluzowej stwierdzono #0# Jakub Dymek, Anna Dymek, Artur Osikowski 20 występowanie komórek przypominających komórki klinowe, co nie było dotąd obserwowane u płazów beznogich. Pomimo obecności owulujących oocytów w żadnym rejonie jajowodu niezaobserwowano plemników, co pozostawia pytanie o występowanie magazynowania plemników u samic tego gatunku wciąż otwartym.