Lactobacillus johnsonii is a dominant Lactobacillus in the murine oral mucosa and has chitinase activity that compromises fungal cell wall integrity.

The oral microbiome is a critical determinant of health and disease, as interactions between oral microorganisms can influence their physiology and the development or severity of oral infections. Lactobacilli have a widely recognized antagonistic relationship with Candida albicans and may exhibit probiotic properties that limit oral fungal infection. We previously reported that Lactobacillus johnsonii strain MT4, an oral strain isolated from C57BL/6 mice, can induce global changes in the murine oral microbiome and has anti-Candida activity in vitro. To build on this information, we analyzed its abundance on the mouse oral mucosa, tested its impact on the severity and progression of oropharyngeal candidiasis (OPC) in a mouse model, and further explored the mechanism of antifungal activity in vitro. Our findings reveal that L. johnsonii MT4 is a dominant cultivable Lactobacillus in the oral mucosa of C57BL/6 mice. Strain MT4 has chitinase activity against C. albicans, which damages the cell wall and compromises fungal metabolic activity. Oral inoculation with strain MT4 causes a reduction in the Candida-induced rise in the abundance of oral enterococci and oral mucosal damage. This research underscores the potential of L. johnsonii strain MT4 as a novel probiotic agent in the prevention or management of OPC, and it contributes to a better understanding of the role of oral bacterial microbiota role in the pathogenesis of fungal infections. IMPORTANCE: The interactions between the opportunistic pathogen Candida albicans and resident oral bacteria are particularly crucial in maintaining oral health. Emerging antifungal drug-resistant strains, slow-paced drug discovery, and the risk of side effects can compromise the effectiveness of current treatments available for oropharyngeal candidiasis. This study advances the search for alternative microbiome-targeted therapies in oral fungal infections. We report that Lactobacillus johnsonii strain MT4 prevents the Candida-induced bloom of dysbiotic oral enterococci and reduces oral mucosal lesions in an oropharyngeal candidiasis murine model. We also show that this strain directly compromises the cell wall and reduces fungal metabolic activity, partly due to its chitinase activity.

Genes associated with fitness and disease severity in the pan-genome of mastitis-associated Escherichia coli.

Introduction: Bovine mastitis caused by Escherichia coli compromises animal health and inflicts substantial product losses in dairy farming. It may manifest as subclinical through severe acute disease and can be transient or persistent in nature. Little is known about bacterial factors that impact clinical outcomes or allow some strains to outcompete others in the mammary gland (MG) environment. Mastitis-associated E. coli (MAEC) may have distinctive characteristics which may contribute to the varied nature of the disease. Given their high levels of intraspecies genetic variability, virulence factors of commonly used MAEC model strains may not be relevant to all members of this group. Methods: In this study, we sequenced the genomes of 96 MAEC strains isolated from cattle with clinical mastitis (CM). We utilized clinical severity data to perform genome-wide association studies to identify accessory genes associated with strains isolated from mild or severe CM, or with high or low competitive fitness during in vivo competition assays. Genes associated with mastitis pathogens or commensal strains isolated from bovine sources were also identified. Results: A type-2 secretion system (T2SS) and a chitinase (ChiA) exported by this system were strongly associated with pathogenic isolates compared with commensal strains. Deletion of chiA from MAEC isolates decreased their adherence to cultured bovine mammary epithelial cells. Discussion: The increased fitness associated with strains possessing this gene may be due to better attachment in the MG. Overall, these results provide a much richer understanding of MAEC and suggest bacterial processes that may underlie the clinical diversity associated with mastitis and their adaptation to this unique environment.

Predictive value of serum HIF-1α/HIF-2α and YKL-40 levels for vascular invasion and prognosis of follicular thyroid cancer.

OBJECTIVE: This study investigated the significance of serum hypoxia-inducible factor (HIF)-1α/HIF-2 α and Chitinase 3-Like protein 1 (YKL-40) levels in the assessment of vascular invasion and prognostic outcomes in patients with Follicular Thyroid Cancer (FTC). METHODS: This prospective study comprised 83 patients diagnosed with FTC, who were subsequently categorized into a recurrence group (17 cases) and a non-recurrence group (66 cases). The pathological features of tumor vascular invasion were classified. Serum HIF-1α/HIF-2α and YKL-40 were quantified using a dual antibody sandwich enzyme-linked immunosorbent assay, while serum Thyroglobulin (Tg) levels were measured using an electrochemiluminescence immunoassay method. The Spearman test was employed to assess the correlation between serum factors, and the predictive value of diagnostic factors was determined using receiver operating characteristic curve analysis. A Cox proportional hazards regression model was utilized to analyze independent factors influencing prognosis. RESULTS: Serum HIF-1α, HIF-2α, YKL-40, and Tg were elevated in patients exhibiting higher vascular invasion. A significant positive correlation was observed between Tg and HIF-1α, as well as between HIF-1α and YKL-40. The cut-off values for HIF-1α and YKL-40 in predicting recurrence were 48.25 pg/mL and 60.15 ng/mL, respectively. Patients exceeding these cut-off values experienced a lower recurrence-free survival rate. Furthermore, serum levels surpassing the cut-off value, in conjunction with vascular invasion (v2+), were identified as independent risk factors for recurrence in patients with FTC. CONCLUSION: Serum HIF-1α/HIF-2α and YKL-40 levels correlate with vascular invasion in FTC, and the combination of HIF-1α and YKL-40 predicts recurrence in patients with FTC.

Identification and functional characterization of the chitinase and chitinase-like gene family in Myzus persicae (Sulzer) during molting.

BACKGROUND: The crucial role of insect chitinase in molting, pupation, and emergence renders it a promising target for pest control strategies. Despite the extensive investigation of chitinase genes in various pests, there is still a lack of systematic identification and functional analysis related to aphid chitinase. RESULTS: We systematically identified a total of nine chitinase/chitinase-like genes and one ENGase gene, which included eight Cht genes, one IDGF gene, and one ENGase gene. Through phylogenetic analysis, the chitinase proteins were classified into nine distinct groups (I, II, III, V, VI, VIII, X, other, and ENGase). The expression profile revealed that the epidermis exhibited relatively high expression levels for three chitinase genes: MpCht5, MpCht7, and MpCht10. Furthermore, transcriptional levels of nine chitinase genes were up-regulated following treatment with 20-hydroxyecdysone (20E) hormone. Silencing MpCht3, MpCht5, MpCht7, MpCht10, and MpCht11-2 via RNA interference (RNAi) during the molting stage resulted in nymph shrinking, hindering normal molting and leading to death. Additionally, it was observed that silencing of MpIDGF induced the body color of the aphids to change from reddish brown to colorless after molting, culminating in eventual mortality. CONCLUSION: Our findings suggest that chitinase/chitinase-like genes play a crucial role in the molting process of Myzus persicae. Utilizing RNAi technology, we aimed to elucidate the precise function of MpCht genes in the molting mechanism of M. persicae, this discovery establishes a significant theoretical foundation for future research on aphid control, with chitinase as the target. © 2024 Society of Chemical Industry.

Selection of marine bacterial consortia efficient at degrading chitin leads to the discovery of new potential chitin degraders.

Chitin degradation is a keystone process in the oceans, mediated by marine microorganisms with the help of several enzymes, mostly chitinases. Sediment, seawater, and filter-feeding marine invertebrates, such as sponges, are known to harbor chitin-degrading bacteria and are presumably hotspots for chitin turnover. Here, we employed an artificial selection process involving enrichment cultures derived from microbial communities associated with the marine sponge Hymeniacidon perlevis, its surrounding seawater and sediment, to select bacterial consortia capable of degrading raw chitin. Throughout the artificial selection process, chitin degradation rates and the taxonomic composition of the four successive enrichment cultures were followed. To the best of our knowledge, chitin degradation was characterized for the first time using size exclusion chromatography, which revealed significant shifts in the numbered average chitin molecular weight, strongly suggesting the involvement of endo-chitinases in the breakdown of the chitin polymer during the enrichment process. Concomitantly with chitin degradation, the enrichment cultures exhibited a decrease in alpha diversity compared with the environmental samples. Notably, some of the dominant taxa in the enriched communities, such as Motilimonas, Arcobacter, and Halarcobacter, were previously unknown to be involved in chitin degradation. In particular, the analysis of published genomes of these genera suggests a pivotal role of Motilimonas in the hydrolytic cleavage of chitin. This study provides context to the microbiome of the marine sponge Hymeniacidon perlevis in light of its environmental surroundings and opens new ground to the future discovery and characterization of novel enzymes of marine origin involved in chitin degradation processes.IMPORTANCEChitin is the second most abundant biopolymer on Earth after cellulose, and the most abundant in the marine environment. At present, industrial processes for the conversion of seafood waste into chitin, chitosan, and chitooligosaccharide (COS) rely on the use of high amounts of concentrated acids or strong alkali at high temperature. Developing bio-based methods to transform available chitin into valuable compounds, such as chitosan and COS, holds promise in promoting a more sustainable, circular bioeconomy. By employing an artificial selection procedure based on chitin as a sole C and N source, we discovered microorganisms so-far unknown to metabolize chitin in the rare microbial biosphere of several marine biotopes. This finding represents a first important step on the path towards characterizing and exploiting potentially novel enzymes of marine origin with biotechnological interest, since products of chitin degradation may find applications across several sectors, such as agriculture, pharmacy, and waste management.

Transcriptomics reveal a mechanism of niche defense: two beneficial root endophytes deploy an antimicrobial GH18-CBM5 chitinase to protect their hosts.

Effector secretion is crucial for root endophytes to establish and protect their ecological niche. We used time-resolved transcriptomics to monitor effector gene expression dynamics in two closely related Sebacinales, Serendipita indica and Serendipita vermifera, during symbiosis with three plant species, competition with the phytopathogenic fungus Bipolaris sorokiniana, and cooperation with root-associated bacteria. We observed increased effector gene expression in response to biotic interactions, particularly with plants, indicating their importance in host colonization. Some effectors responded to both plants and microbes, suggesting dual roles in intermicrobial competition and plant-microbe interactions. A subset of putative antimicrobial effectors, including a GH18-CBM5 chitinase, was induced exclusively by microbes. Functional analyses of this chitinase revealed its antimicrobial and plant-protective properties. We conclude that dynamic effector gene expression underpins the ability of Sebacinales to thrive in diverse ecological niches with a single fungal chitinase contributing substantially to niche defense.

Darifenacin: a promising chitinase 3-like 1 inhibitor to tackle drug resistance in pancreatic ductal adenocarcinoma.

PURPOSE: Pancreatic ductal adenocarcinoma (PDAC) is among the most aggressive malignancies. Our previous work revealed Chitinase 3-like 1 (CHI3L1) involvement in PDAC resistance to gemcitabine, identifying it as a promising therapeutic target. Here, we aimed to identify putative CHI3L1 inhibitors and to investigate their chemosensitizing potential in PDAC. METHODS: Docking analysis for CHI3L1 identified promising CHI3L1 inhibitors, including darifenacin (muscarinic receptor antagonist). PDAC cell lines (BxPC-3, PANC-1) and primary PDAC cells were used to evaluate darifenacin's effects on cell growth (Sulforhodamine B, SRB), alone or in combination with gemcitabine or gemcitabine plus paclitaxel. Cytotoxicity against normal immortalized pancreatic ductal cells (HPNE) was assessed. Recombinant protein was used to confirm the impact of darifenacin on CHI3L1-induced PDAC cellular resistance to therapy (SRB assay). Darifenacin's effect on Akt activation was analysed by ELISA. The association between cholinergic receptor muscarinic 3 (CHRM3) expression and therapeutic response was evaluated by immunohistochemistry of paraffin-embedded tissues from surgical resections of a 68 patients' cohort. RESULTS: In silico screening revealed the ability of darifenacin to target CHI3L1 with high efficiency. Darifenacin inhibited PDAC cell growth, with a GI50 of 26 and 13.6 µM in BxPC-3 and PANC-1 cells, respectively. These results were confirmed in primary PDAC-3 cells, while darifenacin showed no cytotoxicity against HPNE cells. Importantly, darifenacin sensitized PDAC cells to standard chemotherapies, reverted CHI3L1-induced PDAC cellular resistance to therapy, and decreased Akt phosphorylation. Additionally, high CHMR3 expression was associated with low therapeutic response to gemcitabine. CONCLUSION: This work highlights the potential of darifenacin as a chemosensitizer for PDAC treatment.

Response Surface Methodology-Based Optimization of the Chitinolytic Activity of Burkholderia contaminans Strain 614 Exerting Biological Control against Phytopathogenic Fungi.

As part of the development of alternative and environmentally friendly control against phytopathogenic fungi, Burkholderia cepacia could be a useful species notably via the generation of hydrolytic enzymes like chitinases, which can act as a biological control agent. Here, a Burkholderia contaminans S614 strain exhibiting chitinase activity was isolated from a soil in southern Tunisia. Then, response surface methodology (RSM) with a central composite design (CCD) was used to assess the impact of five factors (colloidal chitin, magnesium sulfate, dipotassium phosphate, yeast extract, and ammonium sulfate) on chitinase activity. B. contaminans strain 614 growing in the optimized medium showed up to a 3-fold higher chitinase activity. This enzyme was identified as beta-N-acetylhexosaminidase (90.1 kDa) based on its peptide sequences, which showed high similarity to those of Burkholderia lata strain 383. Furthermore, this chitinase significantly inhibited the growth of two phytopathogenic fungi: Botrytis cinerea M5 and Phoma medicaginis Ph8. Interestingly, a crude enzyme from strain S614 was effective in reducing P. medicaginis damage on detached leaves of Medicago truncatula. Overall, our data provide strong arguments for the agricultural and biotechnological potential of strain S614 in the context of developing biocontrol approaches.

Primate cerebrospinal fluid CHI3L1 reflects brain TREM2 agonism.

INTRODUCTION: Triggering receptor expressed on myeloid cells 2 (TREM2) agonists are being clinically evaluated as disease-modifying therapeutics for Alzheimer's disease. Clinically translatable pharmacodynamic (PD) biomarkers are needed to confirm drug activity and select the appropriate therapeutic dose in clinical trials. METHODS: We conducted multi-omic analyses on paired non-human primate brain and cerebrospinal fluid (CSF), and stimulation of human induced pluripotent stem cell-derived microglia cultures after TREM2 agonist treatment, followed by validation of candidate fluid PD biomarkers using immunoassays. We immunostained microglia to characterize proliferation and clustering. RESULTS: We report CSF soluble TREM2 (sTREM2) and CSF chitinase-3-like protein 1 (CHI3L1/YKL-40) as PD biomarkers for the TREM2 agonist hPara.09. The respective reduction of sTREM2 and elevation of CHI3L1 in brain and CSF after TREM2 agonist treatment correlated with transient microglia proliferation and clustering. DISCUSSION: CSF CHI3L1 and sTREM2 reflect microglial TREM2 agonism and can be used as clinical PD biomarkers to monitor TREM2 activity in the brain. HIGHLIGHTS: CSF soluble triggering receptor expressed on myeloid cells 2 (sTREM2) reflects brain target engagement for a novel TREM2 agonist, hPara.09. CSF chitinase-3-like protein 1 reflects microglial TREM2 agonism. Both can be used as clinical fluid biomarkers to monitor TREM2 activity in brain.

Novel domain-structure-containing chitinases A and B of Bacillus velezensis produced by recombinant Escherichia coli cells: Synergism on chitin degradation and their potential in suppressing Candida albicans cell germination.

Bacillus velezensis RB.IBE29 harbors two chitinases belonging to the glycoside hydrolase family 18 and exhibiting a novel domain structure. The roles of these chitinases in crop production have been reported; nevertheless, their contribution to controlling human pathogens is unknown. In this initial work, the chitinases A (BvChiA) and B (BvChiB) of strain RB.IBE29 were produced in recombinant Escherichia coli BL21-CodonPlus (DE3)-RIPL cells and subsequently purified using HisTrap FF column. The purified BvChiA and BvChiB exhibited the highest chitinase and binding activities against colloidal chitin. Combining both chitinases for the hydrolysis of powdered chitin increased the reducing sugar content by 88.7 %. Moreover, the purified chitinases remarkably suppressed the germination of Candida albicans VTCC 20568 (=JCM 2070) cells. These results indicated that the novel domain-structure-containing chitinases of strain RB.IBE29 have great potential and can be further developed as a novel therapeutic agent against human pathogenic C. albicans.

Chitinase Gene FoChi20 in Fusarium oxysporum Reduces Its Pathogenicity and Improves Disease Resistance in Cotton.

Chitinase genes, as a class of cell wall hydrolases, are essential for the development and pathogenesis of Fusarium oxysporum f.sp. vasinfectum (F. ox) in cotton, but related research focused on chitinase genes are limited. This study explored two island cotton root secretions from the highly resistant cultivar Xinhai 41 and sensitive cultivar Xinhai 14 to investigate their interaction with F. ox by a weighted correlation network analysis (WGCNA). As a result, two modules that related to the fungal pathogenicity emerged. Additionally, a total of twenty-five chitinase genes were identified. Finally, host-induced gene silencing (HIGS) of FoChi20 was conducted, and the cotton plants showed noticeably milder disease with a significantly lower disease index than the control. This study illuminated that chitinase genes play crucial roles in the pathogenicity of cotton wilt fungi, and the FoChi20 gene could participate in the pathogenesis of F. ox and host-pathogen interactions, which establishes a theoretical framework for disease control in Sea Island cotton.

Chitinase 3-like-1 (CHI3L1) in the pathogenesis of epidermal growth factor receptor mutant non-small cell lung cancer.

Non-small cell lung cancer (NSCLC) accounts for 85 % of all lung cancers. In NSCLC, 10-20 % of Caucasian patients and 30-50 % of Asian patients have tumors with activating mutations in the Epidermal Growth Factor Receptor (EGFR). A high percentage of these patients exhibit favorable responses to treatment with tyrosine kinase inhibitors (TKI). Unfortunately, a majority of these patients develop therapeutic resistance with progression free survival lasting 9-18 months. The mechanisms that underlie the tumorigenic effects of EGFR and the ability of NSCLC to develop resistance to TKI therapies, however, are poorly understood. Here we demonstrate that CHI3L1 is produced by EGFR activation of normal epithelial cells, transformed epithelial cells with wild type EGFR and cells with cancer-associated, activating EGFR mutations. We also demonstrate that CHI3L1 auto-induces itself and feeds back to stimulate EGFR and its ligands via a STAT3-dependent mechanism(s). Highly specific antibodies against CHI3L1 (anti-CHI3L1/FRG) and TKI, individually and in combination, abrogated the effects of EGFR activation on CHI3L1 and the ability of CHI3L1 to stimulate the EGFR axis. Anti-CHI3L1 also interacted with osimertinib to reverse TKI therapeutic resistance and induce tumor cell death and inhibit pulmonary metastasis while stimulating tumor suppressor genes including KEAP1. CHI3L1 is a downstream target of EGFR that feeds back to stimulate and activate the EGFR axis. Anti-CHI3L1 is an exciting potential therapeutic for EGFR mutant NSCLC, alone and in combination with osimertinib or other TKIs.

Biochemical Properties of a Novel Cold-Adapted GH19 Chitinase with Three Chitin-Binding Domains from Chitinilyticum aquatile CSC-1 and Its Potential in Biocontrol of Plant Pathogenic Fungi.

GH19 (glycoside hydrolase 19) chitinases play crucial roles in the enzymatic conversion of chitin and biocontrol of phytopathogenic fungi. Herein, a novel multifunctional chitinase of GH19 (CaChi19A), which contains three chitin-binding domains (ChBDs), was successfully cloned from Chitinilyticum aquatile CSC-1 and heterologously expressed in Escherichia coli. We also generated truncated mutants of CaChi19A_ΔI, CaChi19A_ΔIΔII, and CaChi19A_CatD consisting of two ChBDs and a catalytic domain, one ChBD and a catalytic domain, and only a catalytic domain, respectively. CaChi19A, CaChi19A_ΔI, CaChi19A_ΔIΔII, and CaChi19A_CatD exhibited cold adaptation, as their relative enzyme activities at 5 °C were 40.7, 51.6, 66.2, and 82.6%, respectively. Compared with CaChi19A and other variants, CaChi19A_ΔIΔII demonstrated a higher level of stability below 50 °C and retained relatively high activity over a wide pH range of 5-12. Analysis of the hydrolysis products revealed that CaChi19A and CaChi19A_ΔIΔII exhibit exoacting, endoacting, and N-acetyl-ß-d-glucosaminidase activities toward colloidal chitin. Furthermore, CaChi19A and CaChi19A_ΔIΔII exhibited inhibitory effects on the hyphal growth of Fusarium oxysporum, Fusarium redolens, Fusarium fujikuroi, Fusarium solani, and Coniothyrium diplodiella, thereby illustrating effective biocontrol activity. These results indicated that CaChi19A and CaChi19A_ΔIΔII show advantages in some applications where low temperatures were demanded in industries as well as the biocontrol of fungal diseases in agriculture.

Chitinase­3 like­protein­1: A potential predictor of cardiovascular disease (Review).

Chitinase­3 like­protein­1 (CHI3L1), a glycoprotein belonging to the glycoside hydrolase family 18, binds to chitin; however, this protein lacks chitinase activity. Although CHI3L1 is not an enzyme capable of degrading chitin, it plays significant roles in abnormal glucose and lipid metabolism, indicating its involvement in metabolic disorders. In addition, CHI3L1 is considered a key player in inflammatory diseases, with clinical data suggesting its potential as a predictor of cardiovascular disease. CHI3L1 regulates the inflammatory response of various cell types, including macrophages, vascular smooth muscle cells and fibroblasts. In addition, CHI3L1 participates in vascular remodeling and fibrosis, contributing to the pathogenesis of cardiovascular disease. At present, research is focused on elucidating the role of CHI3L1 in cardiovascular disease. The present systematic review was conducted to comprehensively evaluate the effects of CHI3L1 on cardiovascular cells, and determine the potential implications in the occurrence and progression of cardiovascular disease. The present study may further the understanding of the involvement of CHI3L1 in cardiovascular pathology, demonstrating its potential as a therapeutic target or biomarker in the management of cardiovascular disease.

Genome-Wide Identification of a Maize Chitinase Gene Family and the Induction of Its Expression by Fusarium verticillioides (Sacc.) Nirenberg (1976) Infection.

Maize chitinases are involved in chitin hydrolysis. Chitinases are distributed across various organisms including animals, plants, and fungi and are grouped into different glycosyl hydrolase families and classes, depending on protein structure. However, many chitinase functions and their interactions with other plant proteins remain unknown. The economic importance of maize (Zea mays L.) makes it relevant for studying the function of plant chitinases and their biological roles. This work aims to identify chitinase genes in the maize genome to study their gene structure, family/class classification, cis-related elements, and gene expression under biotic stress, such as Fusarium verticillioides infection. Thirty-nine chitinase genes were identified and found to be distributed in three glycosyl hydrolase (GH) families (18, 19 and 20). Likewise, the conserved domains and motifs were identified in each GH family member. The identified cis-regulatory elements are involved in plant development, hormone response, defense, and abiotic stress response. Chitinase protein-interaction network analysis predicted that they interact mainly with cell wall proteins. qRT-PCR analysis confirmed in silico data showing that ten different maize chitinase genes are induced in the presence of F. verticillioides, and that they could have several roles in pathogen infection depending on chitinase structure and cell wall localization.

Sustainable management of peanut damping-off and root rot diseases caused by Rhizoctonia solani using environmentally friendly bio-formulations prepared from batch fermentation broth of chitinase-producing Streptomyces cellulosae.

BACKGROUND: Soil-borne plant diseases represent a severe problem that negatively impacts the production of food crops. Actinobacteria play a vital role in biocontrolling soil-borne fungi. AIM AND OBJECTIVES: The target of the present study is to test the antagonistic activity of chitinase-producing Streptomyces cellulosae Actino 48 (accession number, MT573878) against Rhizoctonia solani. Subsequently, maximization of Actino 48 production using different fermentation processes in a stirred tank bioreactor. Finally, preparation of bio-friendly formulations prepared from the culture broth of Actino 48 using talc powder (TP) and bentonite in a natural as well as nano forms as carriers. Meanwhile, investigating their activities in reducing the damping-off and root rot diseases of peanut plants, infected by R. solani under greenhouse conditions. RESULTS: Actino 48 was found to be the most significant antagonistic isolate strain at p ≤ 0.05 and showed the highest inhibition percentage of fungal mycelium growth, which reached 97%. The results of scanning electron microscope (SEM) images analysis showed a large reduction in R. solani mycelia mass. Additionally, many aberrations changes and fungal hypha damages were found. Batch fermentation No. 2, which was performed using agitation speed of 200 rpm, achieved high chitinase activity of 0.1163 U mL- 1 min- 1 with a yield coefficient of 0.004 U mL- 1 min- 1 chitinase activity/g chitin. Nano-talc formulation of Actino 48 had more a significant effect compared to the other formulations in reducing percentages of damping-off and root rot diseases that equal to 19.05% and 4.76% with reduction percentages of 60% and 80%, respectively. The healthy survival percentage of peanut plants recorded 76.19%. Furthermore, the nano-talc formulation of Actino 48 was sufficient in increasing the dry weight of the peanut plants shoot, root systems, and the total number of peanut pods with increasing percentages of 47.62%, 55.62%, and 38.07%, respectively. CONCLUSION: The bio-friendly formulations of actinobacteria resulting from this investigation may play an active role in managing soil-borne diseases.

Impact of chitin-derived ß-N-acetyl-d-glucosaminyl-(1,4)-d-glucosamine on chitinase upregulation in Shewanella baltica.

The first steps in chitin degradation in marine bacteria involve chitinase, which produces N,N'-diacetylchitobiose (GlcNAc)2 from chitin. Moreover, in Vibrio bacteria, chitinase activity is enhanced by heterodisaccharide ß-N-acetyl-d-glucosaminyl-(1,4)-d-glucosamine (GlcNAc-GlcN) produced from (GlcNAc)2 by chitin oligosaccharide deacetylase (COD). However, the role of COD in other marine bacteria, such as Shewanella, remains unexplored. This study investigates GlcNAc-GlcN's impact on chitinase gene expression and enzyme production in S. baltica ATCC BAA-1091, drawing parallels with Vibrio parahaemolyticus RIMD2210633. Using real-time quantitative PCR, the study assesses the upregulation of chitinase gene expression in S. baltica in response to GlcNAc-GlcN, informed by COD's known ability to produce GlcNAc-GlcN from (GlcNAc)2. In Vibrio, GlcNAc-GlcN considerably upregulates chitinase gene expression. This study posits a similar regulatory mechanism in S. baltica, with preliminary investigations indicating COD's capacity to produce GlcNAc-GlcN. This study highlights the importance of exploring GlcNAc-GlcN's regulatory role in chitin metabolism across diverse marine bacteria. The potential induction of chitinase production in S. baltica suggests broader ecological implications. Further research is crucial for a comprehensive understanding of chitin utilization and regulatory pathways in marine bacterial genera.

Functional role of carbohydrate-binding modules in multi-modular chitinase OfChtII.

The primary distinction between insect and bacterial chitin degradation systems lies in the presence of a multi-modular endo-acting chitinase ChtII, in contrast to a processive exo-acting chitinase. Although the essential role of ChtII during insect development and its synergistic action with processive chitinase during chitin degradation has been established, the mechanistic understanding of how it deconstructs chitin remains largely elusive. Here OfChtII from the insect Ostrinia furnacalis was investigated employing comprehensive approaches encompassing biochemical and microscopic analyses. The results demonstrated that OfChtII truncations with more carbohydrate-binding modules (CBMs) exhibited enhanced hydrolysis activity, effectively yielding a greater proportion of fibrillary fractions from the compacted chitin substrate. At the single-molecule level, the CBMs in these OfChtII truncations have been shown to primarily facilitate chitin substrate association rather than dissociation. Furthermore, a greater number of CBMs was demonstrated to be essential for the enzyme to effectively bind to chitin substrates with high crystallinity. Through real-time imaging by high-speed atomic force microscopy, the OfChtII-B4C1 truncation with three CBMs was observed to shear chitin fibers, thereby generating fibrillary fragments and deconstructing the compacted chitin structure. This work pioneers in revealing the nanoscale mechanism of endo-acting multi-modular chitinase involved in chitin degradation, which provides an important reference for the rational design of chitinases or other glycoside hydrolases.

Identification of chitinase from Bacillus velezensis strain S161 and its antifungal activity against Penicillium digitatum.

Previous studies have demonstrated the presence of chitinase in Bacillus velezensis through extensive genomic sequencing and experimental analyses. However, the detailed structure, functional roles, and antifungal activity of these chitinases remain poorly characterized. In this study, genomic screening identified three genes-chiA, chiB, and lpmo10-associated with chitinase degradation in B. velezensis S161. These genes encode chitinases ChiA and ChiB, and lytic polysaccharide monooxygenase LPMO10. Both ChiA and ChiB contain two CBM50 binding domains and one catalytic domain, whereas LPMO10 includes a signal peptide and a single catalytic domain. The chitinases ChiA, its truncated variant ChiA2, and ChiB were heterologously expressed in Escherichia coli. The purified enzymes efficiently degraded colloidal chitin and inhibited the spore germination of Penicillium digitatum. Notably, even after losing one CBM50 domain, the resultant enzyme, consisting of the remaining CBM50 domain and the catalytic domain, maintained its colloidal chitin hydrolysis and antifungal activity, indicating commendable stability. These results underscore the role of B. velezensis chitinases in suppressing plant pathogenic fungi and provide a solid foundation for developing and applying chitinase-based biocontrol strategies.

Evaluation of the relationship between YKL-40 level and clinical severity in patients with Crimean-Congo hemorrhagic fever.

Crimean-Congo hemorrhagic fever (CCHF) is a widespread tick-borne viral disease. YKL-40 (also known as chitinase-3-like-1 protein) is an acute phase protein released by various immune cells. The purpose of this study was to investigate the relationship between YKL-40 level and the clinical course and prognosis of CCHF. The study included 78 patients who were admitted to our hospital between April 15 and 30 August 2022 and had a positive polymerase chain reaction test result for CCHF. The patients were divided into two groups, severe and non-severe. In addition, a control group consisting of 22 healthy people was established. Mean serum YKL-40 levels were significantly higher in patients than controls (106.8 ng/mL ± 91.2 and 47.1 ng/mL ± 35.3, respectively; p < 0.001). However, mean YKL-40 levels were also significantly higher in patients with severe CCHF compared to non-severe cases (173.3 ± 112.3 and 67.5 ± 41.7, respectively; p < 0.001). A comparison of the 10 exitus patients and the 68 survivors revealed significantly higher YKL-40 levels in the exitus group (mean: 214.0 ± 139.0 and 92.8 ± 73.6, respectively; p = 0.001). A receiver operating characteristic analysis for YKL-40 levels to distinguish between severe and non-severe patients found an area under the curve of 0.925. YKL-40 levels were measured with a sensitivity of 97% and a specificity of 84% with a cutoff value of 90.7 ng/mL. YKL-40 levels measured at the time of hospital presentation in patients with CCHF can be used as a biomarker for clinical course and prognosis.