The JAK (Janus kinase)-STAT (Signal transducer and activator of transcription) is a well-known functional signaling pathway that plays a key role in several important biological activities such as apoptosis, cell proliferation, differentiation, and immunity. However, limited studies have explored the functions of STAT genes in invertebrates. In the present study, the gene sequences of two STAT genes from the Pacific oyster (Crassostrea gigas), termed CgSTAT-Like-1 (CgSTAT-L1) and CgSTAT-Like-2 (CgSTAT-L2), were obtained using polymerase chain reaction (PCR) amplification and cloning. Multiple sequence comparisons revealed that the sequences of crucial domains of these proteins were conserved, and the similarity with the protein sequence of other molluscan STAT is close to 90 %. The phylogenetic analyses indicated that CgSTAT-L1 and CgSTAT-L2 are novel members of the mollusk STAT family. Quantitative real-time PCR results implied that CgSTAT-L1 and CgSTAT-L2 mRNA expression was found in all tissues, and significantly induced after challenge with lipopolysaccharide (LPS), peptidoglycan (PGN), or poly(I:C). After that, dual-luciferase reporter assays denoted that overexpression of CgSTAT-L1 and CgSTAT-L2 significantly activated the NF-κB signaling, and, interestingly, the overexpressed CgSTAT proteins potentiated LPS-induced NF-κB activation. These results contributed a preliminary analysis of the immune-related function of STAT genes in oysters, laying the foundation for deeper understanding of the function of invertebrate STAT genes.

Peptidoglycan is a carbohydrate with a cross-linked structure that protects the cytoplasmic membrane of bacterial cells from damage. The mechanism of peptidoglycan biosynthesis involves the main synthesizing enzyme glycosyltransferase MurG, which is known as a potential target for antibiotic therapy. Many MurG inhibitors have been recognized as MurG targets, but high toxicity and drug-resistant Escherichia coli strains remain the most important problems for further development. In addition, the discovery of selective MurG inhibitors has been limited to the synthesis of peptidoglycan-mimicking compounds. The present study employed drug discovery, such as virtual screening using molecular docking, drug likeness ADMET proprieties predictions, and molecular dynamics (MD) simulation, to identify potential natural products (NPs) for Escherichia coli. We conducted a screening of 30,926 NPs from the NPASS database. Subsequently, 20 of these compounds successfully passed the potency, pharmacokinetic, ADMET screening assays, and their validation was further confirmed through molecular docking. The best three hits and the standard were chosen for further MD simulations up to 400 ns and energy calculations to investigate the stability of the NPs-MurG complexes. The analyses of MD simulations and total binding energies suggested the higher stability of NPC272174. The potential compounds can be further explored in vivo and in vitro for promising novel antibacterial drug discovery.

Bacterial SPOR domains target proteins to the divisome by binding septal peptidoglycan (PG) at sites where cell wall amidases have removed stem peptides. These PG structures are referred to as denuded glycans. Although all characterized SPOR domains bind denuded glycans, whether there are differences in affinity is not known. Here, we use isothermal titration calorimetry (ITC) to determine the relative PG glycan binding affinity (<i>K</i>_d) of four Escherichia coli SPOR domains and one Cytophaga hutchinsonii SPOR domain. We found that the <i>K</i>_d values ranged from approximately 1 μM for E. coli DamX^SPOR and <i>C. hutchinsonii</i> CHU2221^SPOR to about 10 μM for E. coli FtsN^SPOR. To investigate whether these differences in PG binding affinity are important for SPOR domain protein function, we constructed and characterized a set of DamX and FtsN \"swap\" proteins. As expected, all SPOR domain swap proteins localized to the division site, and, in the case of FtsN, all of the heterologous SPOR domains supported cell division. However, for DamX, only the high-affinity SPOR domain from CHU2221 supported normal function in cell division. In summary, different SPOR domains bind denuded PG glycans with different affinities, which appears to be important for the functions of some SPOR domain proteins (e.g., DamX) but not for the functions of others (e.g., FtsN). <b>IMPORTANCE</b> SPOR domain proteins are prominent components of the cell division apparatus in a wide variety of bacteria. The primary function of SPOR domains is targeting proteins to the division site, which they accomplish by binding to septal peptidoglycan. However, whether SPOR domains have any functions beyond septal targeting is unknown. Here, we show that SPOR domains vary in their PG binding affinities and that, at least in the case of the E. coli cell division protein DamX, having a high-affinity SPOR domain contributes to proper function.

The prevalence of oral health problems in the global population is still high, especially dental caries, which is considered a multifactorial disease involving the role of bacteria, namely Streptococcus mutans. Gram-positive bacteria metabolize carbohydrates and sugars and convert them into lactic acid, causing dental caries. The peptidoglycan (PG) layer at the outer surface of the bacteria acts as protection. MurB enzyme is known for its contribution to PG biosynthesis. Gambir (Uncaria gambir Roxb.) is famous for many efficacies. Previous studies show that catechin from herb plants such as U. gambir has antibacterial activity. This study aimed to evaluate and predict the antibacterial activity of catechin from U. gambir against the MurB enzyme, which contributes to forming the bacteria PG, with an in silico approach. The structure of the MurB enzyme was collected from UniProt, and the ligands (catechin and chlorhexidine) structures were obtained from PubChem. The AutoDock software was used to dock both ligand and MurB enzyme visualized using PyMOL and analyzed using BIOVIA. The results showed that catechin has a binding affinity of more than - 7 kcal/mol against the MurB enzyme, and chlorhexidine has a higher binding affinity than catechin. Both catechin and chlorhexidine have similar amino acids attachment by hydrogen bonds. The results showed that catechin has competitive antibacterial activity against chlorhexidine in inhibiting the MurB enzyme.

This study aimed to assess the diagnostic values of peptidoglycan (PGN), lipopolysaccharide (LPS) and (1,3)-Beta-D-Glucan (BDG) in patients with suspected bloodstream infection. We collected 493 heparin anticoagulant samples from patients undergoing blood culture in Peking Union Medical College Hospital from November 2020 to March 2021. The PGN, LPS, and BDG in the plasma were detected using an automatic enzyme labeling analyzer, GLP-F300. The diagnostic efficacy for PGN, LPS, and BDG were assessed by calculating the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). This study validated that not only common bacteria and fungi, but also some rare bacteria and fungi, could be detected by testing the PGN, LPS, and BDG, in the plasma. The sensitivity, specificity, and total coincidence rate were 83.3%, 95.6%, and 94.5% for PGN; 77.9%, 95.1%, and 92.1% for LPS; and 83.8%, 96.9%, and 95.9% for BDG, respectively, which were consistent with the clinical diagnosis. The positive rates for PGN, LPS, and BDG and the multi-marker detection approach for PGN, LPS, and BDG individually were 11.16%, 17.65%, and 9.13%, and 32.86% significantly higher than that of the blood culture (p < 0.05). The AUC values for PGN, LPS, and BDG were 0.881 (0.814−0.948), 0.871 (0.816−0.925), and 0.897 (0.825−0.969), separately, which were higher than that of C-reactive protein (0.594 [0.530−0.659]) and procalcitonin (0.648 [0.587−0.708]). Plasma PGN, LPS, and BDG performs well in the early diagnosis of bloodstream infections caused by Gram-positive and Gram-negative bacterial and fungal pathogens.

How proteins move through space and time is a fundamental question in biology. While great strides have been made toward a mechanistic understanding of protein movement, many questions remain. We discuss the biological implications of motion in the context of the peptidoglycan (PG) synthesis machines. We reviewed systems in several bacteria, including Escherichia coli, Bacillus subtilis, and Streptococcus pneumoniae, and present a comprehensive view of our current knowledge regarding movement dynamics. Discrepancies are also addressed because \"one size does not fit all\". For bacteria to divide, new PG is synthesized and incorporated into the growing cell wall by complex multiprotein nanomachines consisting of PG synthases (transglycosylases [TG] and/or transpeptidases [TP]) as well as a variety of regulators and cytoskeletal factors. Advances in imaging capabilities and labeling methods have revealed that these machines are not static but rather circumferentially transit the cell via directed motion perpendicular to the long axis of model rod-shaped bacteria such as E. coli and B. subtilis. The enzymatic activity of the TG:TPs drives motion in some species while motion is mediated by FtsZ treadmilling in others. In addition, both directed and diffusive motion of the PG synthases have been observed using single-particle tracking technology. Here, we examined the biological role of diffusion regarding transit. Lastly, findings regarding the monofunctional transglycosylases (RodA and FtsW) as well as the Class A PG synthases are discussed. This minireview serves to showcase recent advances, broach mechanistic unknowns, and stimulate future areas of study.

Cationic peptide chimeric lysins, Lysqdvp001-5aa, Lysqdvp001-10aa and Lysqdvp001-15aa, were designed based on lysin Lysqdvp001 from Vibrio parahaemolyticus (V. parahaemolyticus) phage qdvp001. These chimeric lysins showed equivalent peptidoglycan hydrolysis activities with Lysqdvp001 and could lyse the bacteria from the outside. The antibacterial activity as well as outer and inner membrane permeabilization of Lysqdvp001 and chimeric lysins against V. parahaemolyticus were Lysqdvp001-15aa>Lysqdvp001-10aa>Lysqdvp001-5aa>Lysqdvp001. Lysqdvp001-15aa exhibited an excellent antibacterial activity with minimum inhibition and bactericidal concentrations (MIC and MBC) of 0.2 and 0.4 mg/mL, respectively, and its antibacterial spectrum was much broader than phage qdvp001. Membrane hyperpolarization and membrane phospholipid exposure of V. parahaemolyticus were observed after Lysqdvp001-15aa treatments. Transmission electron microscope (TEM) showed Lysqdvp001-15aa destroyed structure integrity of V. parahaemolyticus. Besides, MIC and MBC of Lysqdvp001-15aa decreased V. parahaemolyticus counts in oyster by 3.20 and 4.03 log10CFU/g. Lysqdvp001-15aa at MBC eradicated about 50% of V. parahaemolyticus biofilms and inhibited over 90% of the formation of the bacterial biofilms.

UNASSIGNED: Dental caries is a widespread disease that causes dental tissue destruction and leads to local and general complications. Gram-positive bacteria including Streptococcus mutans, Streptococcus sanguinis, and Enterococcus faecalis take part in dental caries formation. Gram-positive bacteria have cell walls that consistof a thick layer of peptidoglycan which maintains the strength and rigidity of the bacteria, as well as bacteria guard from internal osmotic pressure. The biosynthesis of peptidoglycan involves many enzymes, including the Mur family, penicillin binding protein (PBP), and sortases.
UNASSIGNED: This research has the intention to screen and examine the antibacterial compound of edible plant Kemangi (Ocimum basilicum L.) in terms of how it fights against some oral pathogenic bacteria of E. faecalis ATCC 29212, S. mutans ATCC 25175, and S. sanguinis ATCC 10566.
UNASSIGNED: The O. basilicum L. was macerated by several organic solvents to obtain the extracts, before then being purified using several combinations of chromatography methods and the compound was discovered via spectroscopic methods. For the assay against bacteria, the extracts and compounds were tested using agar well diffusion and microdilution assay.
UNASSIGNED: The isolated compound was identified as β-sitosterol. The compound activity against bacteria was evaluated by in vitro assay against S. sanguinis ATCC 10566 and E. faecalis ATCC 29212 with the MIC and MBC value of 25,000 and 50,000 ppm, respectively. The compound was also tested by in silico study using the molecular docking method. The molecular interaction between β-sitosterol and the protein target showed a lower binding affinity value than the native ligand and other positive controls for each protein. Based on the amino acid residue bound to the ligands, β-sitosterol on MurA and SrtA is not competitive to the positive control, showing potential as a natural antibacterial agent. Meanwhile, on the MurB and PBP, β-sitosterol and positive control do compete with each other.
UNASSIGNED: The compound, isolated from O. basilicum L. leaf, was determined as β-sitosterol, which has the molecular formula C29H50O. The antibacterial activity of β-sitosterol by in vitro assay showed weak antibacterial activity, yet exhibited the potential to inhibit the biosynthesis of peptidoglycan and prevent bacteria cell wall formation by inhibiting MurA and SrtA activity via docking simulation.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is a deadly disease that lack of effective therapeutic drugs. K-001 is an oral antitumor drug made from active ingredients of marine microorganisms. The current study aimed to evaluate safety and antitumor activity of K-001 in patients with advanced PDAC.
METHODS: In this phase I, open-label trial, patients with advanced PDAC were recruited to a dose-escalation study in a standard 3 + 3 design. K-001 was administered twice daily in four-week cycles, and dose escalation from 1350 mg to 2160 mg was evaluated twice daily. Physical examination and laboratory tests were done at screening and then weekly. The safety, dose-limiting toxicity (DLT), and maximum tolerated dose (MTD) of K-001 were assessed while tumor response was estimated by Response Evaluation Criteria in Solid Tumor (RECIST).
RESULTS: Eighteen patients with advanced PDAC were screened, and twelve eligible patients were analyzed in the study. No DLT was observed. Totally, 47 adverse events (AEs) presented, and 14 drug-related AEs were reported in 7 patients, including 8 grade 1 events (57.1%) and 6 grade 2 events (42.9%). There was no grade 3 or 4 drug-related AE. In these 14 drug-related AEs, the most frequent ones were dyspepsia (21.4%), followed by flatulence, constipation, and hemorrhoid bleeding (above 10% of each). Among all 12 patients, 10 patients (83.3%) maintained stable disease (SD), and 2 patients (16.7%) had progressive disease (PD). The objective response rate (ORR) was 0% and the disease control rate (DCR) was 83.3%.
CONCLUSIONS: K-001 manifests satisfactory safety and tolerability, as well as meaningful antitumor activity in advanced PDAC patients. Further evaluation of K-001 in phase II/III appears warranted.
BACKGROUND: NCT02720666 . Registered 28 Match 2016 - Retrospectively registered.

Galectin-9 is a β-galactoside-binding lectin which could modulate a variety of biological functions including recognition, aggregation and clearance of pathogen. In this study, one Galectin-9 (named PoGalectin-9) was identified from Japanese flounder Paralichthys olivaceus. PoGalectin-9 belongs to the tandem-repeat type, containing one 127-amino acids CRD domain within N terminal and one 122-amino acids CRD domain within C-terminal. The open reading frame of PoGalectin-9 cDNA was 921 bp encoding 306 amino acids. Sequence similarity comparison confirmed that PoGalectin-9 shared high homology with other Galectin-9. The tissue distribution and expression profiles after bacterial infection were also investigated. PoGalectin-9 was widely distributed in all of the examined tissues of Japanese flounder but was predominantly expressed in the spleen, kidney and intestine. After Edwardsiella tarda challenge, the expression of PoGalectin-9 was up-regulated in spleen and down regulated in kidney. ELISA experiment showed that recombinant PoGalectin-9 (rPoGalectin-9) exhibit binding capacity to lipopolysaccharide (LPS) and peptidoglycan (PGN), which is significantly correlated with the concentration of rPoGalectin-9. Meanwhile, the rPoGalectin-9 protein showed strong agglutinating activities against both Gram-negative bacteria and Gram-positive bacteria. Bacterial binding experiments showed that rPoGalectin-9 could bind all examined bacteria. In conclusion, the present study indicate that PoGalectin-9 might play important roles during the immune responses of Japanese flounder against bacterial pathogens.