The Effect of Chitosan Hydrolysate on Solanum Lycopersicum Plant Growth

Chitosan is a well-known subjectof researchbecause of its beneficial properties, including its antibacterial and fungicidal activity, as well as its effect on plant physiology. One of the maindifficulties in agricultural chitosan implementation is the poor solubility of high molecular chitosan in water. Reducing themolecular weight of chitosan by acid hydrolysis increases its solubility. This research studied the effect of chitosan hydrolysate on the germination and development ofSolanum lycopersicum L. plants. Theeffects of chitosan hydrolysate on seed germination, shoot development in the first week of development and in the first month of development were evaluated. According to the results, high concentrations of chitosan hydrolysate completely inhibited seed germination. However, short-term treatment by high concentrations of chitosan hydrolysate stimulatedthe development of seedlings, leading to substantially longerroots. Regular root application of high concentrations of chitosan hydrolysate inhibited plant development. Keywords: chitosan hydrolysate, chitosan, plant growth regulators, plant germination

Lysinibacillus Isolate MK212927: A Natural Producer of Allylamine Antifungal ‘Terbinafine’

Resistance to antifungal agents represents a major clinical challenge, leading to high morbidity and mortality rates, especially in immunocompromised patients. In this study, we screened soil bacterial isolates for the capability of producing metabolites with antifungal activities via the cross-streak and agar cup-plate methods. One isolate, coded S6, showed observable antifungal activity against Candida (C.) albicans ATCC 10231 and Aspergillus (A.) niger clinical isolate. This strain was identified using a combined approach of phenotypic and molecular techniques as Lysinibacillus sp. MK212927. The purified metabolite displayed fungicidal activity, reserved its activity in a relatively wide range of temperatures (up to 60 °C) and pH values (6–7.8) and was stable in the presence of various enzymes and detergents. As compared to fluconazole, miconazole and Lamisil, the minimum inhibitory concentration of the metabolite that showed 90% inhibition of the growth (MIC90) was equivalent to that of Lamisil, half of miconazole and one fourth of fluconazole. Using different spectroscopic techniques such as FTIR, UV spectroscopy, 1D NMR and 2D NMR techniques, the purified metabolite was identified as terbinafine, an allylamine antifungal agent. It is deemed necessary to note that this is the first report of terbinafine production by Lysinibacillus sp. MK212927, a fast-growing microbial source, with relatively high yield and that is subject to potential optimization for industrial production capabilities.

Synthesis and pesticidal activity of some 4-Azolylmethyl-1,3-dioxolanes, based on cyclic ketones

In vitro tests of substituted 1,3-dioxolanes, based on cyclic ketones and substituted with 1H-1,2,4-triazole and 1H-imidazole showed a fungicidal activity lower than the activity of the triadimefon, and spiroxamine. Studied compounds in the entire concentration range: from 0.001 to 10 mg/L showed noticeable retardant properties. The target compounds were derived by cyclization of substituted cyclohexanones with epichlorohydrin followed by alkylation of the derived 2 chloromethyl-1,3 dioxolanes of sodium salts of imidazole or 1,2,4-triazole.

Research on Crystal Structure and Fungicidal Activity of the Amide Derivatives Based on the Natural Products Sinapic Acid and Mycophenolic Acid

Structural optimization based on natural products is an important and effective way to discover new green pesticides. Here, two series of amide derivatives based on sinapic acid and mycophenolic acid were designed in combination with the fungicidal natural product piperlongumine and synthesized by preparing the carboxylic acid into acyl chloride and then reacting with the corresponding aromatic amines, respectively. The resulting structures were successively characterized by 1H NMR, 13 C NMR, and HRMS. The crystal structures of molecules I-4 and II-5 were analyzed for structure validation. The in vitro inhibitory activity indicated that most of the target products exhibited fungicidal activity equivalent to or even better than fluopyram against Physalospora piricola. The in vivo fungicidal activity demonstrated that the compounds I-5 and II-4 displayed almost the same preventative activity as carbendazim and fluopyram at 200 μg mL−1. The TEM observation revealed that the fungicidal activity of the target molecules against Physalospora piricola may be due to the influence on the mitochondria in the cell structure. These results will provide valuable theoretical guidance for developing the new green fungicides.

Envisaging Antifungal Potential of Histatin 5: A Physiological Salivary Peptide

Fungi are reported to cause a range of superficial to invasive human infections. These often result in high morbidity and at times mortality. Conventional antifungal agents though effective invariably exhibit drug interactions, treatment-related toxicity, and fail to elicit significant effect, thus indicating a need to look for suitable alternatives. Fungi thrive in humid, nutrient-enriched areas. Such an environment is well-supported by the oral cavity. Despite this, there is a relatively low incidence of severe oral and periodontal fungal infections, attributed to the presence of antimicrobial peptides hosted by saliva, viz. histatin 5 (Hstn 5). It displays fungicidal activity against a variety of fungi including Candida albicans, Candida glabrata, Candida krusei, Cryptococcus neoformans, and unicellular yeast-like Saccharomyces cerevisiae. Candida albicans alone accounts for about 70% of all global fungal infections including periodontal disease. This review intends to discuss the scope of Hstn 5 as a novel recourse for the control of fungal infections.

Comparative assessment of fungicidal activity of widespread wild-growing and endemic species of the Allium genus growing in Tajikistan

Aim. To conduct a comparative assessment of the fungicidal activity of widespread and endemic species of the genus Allium growing in Tajikistan.Material and methods. The initial ethanol extracts were obtained from fresh plants of 15 onion species from different climatic and geographical regions of the Republic of Tajikistan. The antifungal activity of species of the genus Allium was studied against the yeast-like fungi Candida albicans using the disk diffusion method.Results: The highest fungicidal effect on the reference strain of Candida albicans was demonstrated by alcoholic extracts of the widespread wild species A. elatum Regel, A. oschaninii O. Fedtsch, A. obliguum L, and endemic species A. shugnanicum Vved. Low antifungal activity was found in extracts of 4 widespread wild-growing plant species - A. altaicum Pall, A. suworowii Regel, A. carolinianum DC, A.longicuspis L.Conclusions. The antifungal activity of 13 species of widespread wild-growing and 2 endemic species (A.shugnanicum Vved and A. pamiricum Wendelbo) was studied for the first time. A. elatum Regel, A. oschaninii O. Fedtsch, A. obliguum L, and endemic species A. shugnanicum Vved had a maximal inhibitory effect on the yeast fungus. The extracts obtained from the bulbs and seeds of the studied plants are characterized by the highest antifungal activity.

Effectiveness of the Influence of Selected Essential Oils on the Growth of Parasitic Fusarium Isolated from Wheat Kernels from Central Europe

The aim of the study was to determine the effectiveness of selected seven commercial essential oils (EsO) (grapefruit, lemongrass, tea tree (TTO), thyme, verbena, cajeput, and Litsea cubeba) on isolates of common Central European parasitic fungal species of Fusarium obtained from infected wheat kernels, and to evaluate the oils as potential natural fungicides. The study was conducted in 2 stages. At each stage, the fungicidal activity of EsO (with concentrations of 0.025; 0.05; 0.125; 0.25; 0.50; 1.0, and 2.0%) against Fusarium spp. was evaluated using the disc plate method and zones of growth inhibition were measured. At the first stage, the fungistatic activity of EsO was evaluated against four species of Fusarium from the Polish population (F. avenaceum FAPL, F. culmorum FCPL, F. graminearum FGPL and F. oxysporum FOPL). The correlation coefficient between the mycelial growth rate index (T) and the fungistatic activity (FA) was calculated. At the second stage, on the basis of the mycelium growth rate index, the effectiveness of the EsO in limiting the development of Fusarium isolates from the German population (F. culmorum FC1D, F. culmorum FC2D, F. graminearum FG1D, F. graminearum FG2D and F. poae FP0D) was assessed. The first and second stage results presented as a growth rate index were then used to indicate essential oils (as potential natural fungicides) effectively limiting the development of various common Central European parasitic species Fusarium spp. Finally, the sensitivity of four Fusarium isolates from the Polish population and five Fusarium isolates from the German population was compared. The data were compiled in STATISTICA 13.0 (StatSoft, Inc, CA, USA) at the significance level of 0.05. Fusarium isolates from the German population were generally more sensitive than those from the Polish population. The sensitivity of individual Fusarium species varied. Their vulnerability, regardless of the isolate origin, in order from the most to the least sensitive, is as follows: F. culmorum, F. graminearum, F. poae, F. avenaceum and F. oxysporum. The strongest fungicidal activity, similar to Funaben T, showed thyme oil (regardless of the concentration). Performance of citral oils (lemongrass and Litsea cubeba) was similar but at a concentration above 0.025%.