A review on endophytic fungi: a potent reservoir of bioactive metabolites with special emphasis on blight disease management

Phytopathogenic microorganisms have caused blight diseases that present significant challenges to global agriculture. These diseases result in substantial crop losses and have a significant economic impact. Due to the limitations of conventional chemical treatments in effectively and sustainably managing these diseases, there is an increasing interest in exploring alternative and environmentally friendly approaches for disease control. Using endophytic fungi as biocontrol agents has become a promising strategy in recent years. Endophytic fungi live inside plant tissues, forming mutually beneficial relationships, and have been discovered to produce a wide range of bioactive metabolites. These metabolites demonstrate significant potential for fighting blight diseases and provide a plentiful source of new biopesticides. In this review, we delve into the potential of endophytic fungi as a means of biocontrol against blight diseases. We specifically highlight their significance as a source of biologically active compounds. The review explores different mechanisms used by endophytic fungi to suppress phytopathogens. These mechanisms include competing for nutrients, producing antifungal compounds, and triggering plant defense responses. Furthermore, this review discusses the challenges of using endophytic fungi as biocontrol agents in commercial applications. It emphasizes the importance of conducting thorough research to enhance their effectiveness and stability in real-world environments. Therefore, bioactive metabolites from endophytic fungi have considerable potential for sustainable and eco-friendly blight disease control. Additional research on endophytes and their metabolites will promote biotechnology solutions.

Stress-Tolerant Dormant Bacterial Forms: Biological and Ultrastructural Properties of Moraxella catarrhalis and Kocuria rhizophila

Dormant forms of causative agents of healthcare-acquired infections Moraxella catarrhalis and Kocuria rhizophila have been obtained. Dormant forms cells retained viability during long-term storage (≈107 CFU/ml after 2 months) under provocative conditions (lack of nutrient sources; temperature 20°C, oxygen access) were characterized by heat resistance, and acquired special ultrastructural organization typical of dormant forms (compacted nucleoid, thickened cell wall). They were also capable of forming alternative phenotypes (dominant and small colony variants) in a new cycle of germination in a fresh medium. These results demonstrate that the dormant forms can be responsible both for survival in the environment and persistence in the host organism.

Microbial Biofilms at Meat-Processing Plant as Possible Places of Bacteria Survival

Biofilm contamination in food production threatens food quality and safety, and causes bacterial infections. Study of food biofilms (BF) is of great importance. The taxonomic composition and structural organization of five foods BF taken in different workshops of a meat-processing plant (Moscow, RF) were studied. Samples were taken from the surface of technological equipment and premises. Metagenomic analysis showed both similarities in the presented microorganisms dominating in different samples, and unique families prevailing on certain objects were noted. The bacteria found belonged to 11 phyla (no archaea). The dominant ones were Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria. The greatest diversity was in BFs taken from the cutting table of raw material. Biofilms’ bacteria may be the cause of meat, fish and dairy products spoilage possible representatives include Pseudomonas, Flavobacterium, Arcobacter, Vagococcus, Chryseobacterium, Carnobacterium, etc.). Opportunistic human and animal pathogens (possible representatives include Arcobacter, Corynebacterium, Kocuria, etc.) were also found. Electron-microscopic studies of BF thin sections revealed the following: (1) the diversity of cell morphotypes specific to multispecies BFs; (2) morphological similarity of cells in BFs from different samples, micro-colonial growth; (3) age heterogeneity of cells within the same microcolony (vegetative and autolyzed cells, resting forms); (4) heterogeneity of the polymer matrix chemical nature according to ruthenium red staining.

[Diagnostic and prognostic significance of the hypoxia-dependent transcriptional mediator for the development of a carious lesion]

OBJECTIVE

To study diagnostic informational content of change of concentration a hypoxia-inducible factor (HIF-1α) in gingival liquid of patients for assessment of risk of development of carious process.

MATERIAL AND METHODS

75 patients with the diagnosis dentine caries entered the research: group 1 (n=30) involved patients with primary caries while group 2 (n=45) consisted of patients with caries recurrence in 12 months after treatment.

RESULTS

In all patients HIF-1α was determined in gingival liquid before treatment by the IFA method. Logistic regression and the ROC analysis were used for the statistical analysis. In group 2 the level of HIF-1α was two-fold higher than in group 1 (p<0.001) and 82% higher than in healthy individuals (p<0.001). The increased initial HIF-1α level of 98 pg/ml was associated with high risk of caries recurrence in 12 months after treatment with diagnostic sensitivity of 88.4% and diagnostic specificity of 78.1% with chances of development increased by 4 times (p<0.0001). The change of HIF-1α in gingival liquid from 80 pg/ml to 170 pg/ml increased the risk of caries recurrence 12 months from 13% up to 94%.

CONCLUSION

The initial content in gingival liquid a hypoxia-inducible factor-1α higher than 98 pg/ml allows triage of patients with high risk of caries recurrence requiring dental monitoring for personification of preventive measures.