A subunit vaccine against pneumonia: targeting Streptococcus pneumoniae and Klebsiella pneumoniae.

Community-acquired pneumonia is primarily caused by Streptococcus pneumoniae and Klebsiella pneumoniae, two pathogens that have high morbidity and mortality rates. This is largely due to bacterial resistance development against current antibiotics and the lack of effective vaccines. The objective of this work was to develop an immunogenic multi-epitope subunit vaccine capable of eliciting a robust immune response against S. pneumoniae and K. pneumoniae. The targeted proteins were the pneumococcal surface proteins (PspA and PspC) and choline-binding protein (CbpA) of S. pneumoniae and the outer membrane proteins (OmpA and OmpW) of K. pneumoniae. Different computational approaches and various immune filters were employed for designing a vaccine. The immunogenicity and safety of the vaccine were evaluated by utilizing many physicochemical and antigenic profiles. To improve structural stability, disulfide engineering was applied to a portion of the vaccine structure with high mobility. Molecular docking was performed to examine the binding affinities and biological interactions at the atomic level between the vaccine and Toll-like receptors (TLR2 and 4). Further, the dynamic stabilities of the vaccine and TLRs complexes were investigated by molecular dynamics simulations. While the immune response induction capability of the vaccine was assessed by the immune simulation study. Vaccine translation and expression efficiency was determined through an in silico cloning experiment utilizing the pET28a(+) plasmid vector. The obtained results revealed that the designed vaccine is structurally stable and able to generate an effective immune response to combat pneumococcal infection. Supplementary Information: The online version contains supplementary material available at 10.1007/s13721-023-00416-3.

LPD-12: a promising lipopeptide to control COVID-19.

INTRODUCTION: The recent pandemic outbreak of SARS-CoV-2 has been associated with a lethal atypical pneumonia, making COVID-19 an urgent public health issue with an increasing rate of mortality and morbidity. There are currently no vaccines or therapeutics available for COVID-19, which is causing an urgent search for a new drug to combat the COVID-19 pandemic. The lipid membrane alternation efficiency of small antimicrobial lipopeptides enables them to block viral membrane fusion to the host cell. Lipopeptides could serve as potential antiviral agents, by interacting or competing with viral fusion proteins. METHODS: This study screened seven different lipopeptides (tsushimycin, daptomycin, surfactin, bacillomycin, iturin, srfTE, and LPD-12) and docked them individually against the spike (S)-glycoprotein of SARS-CoV-2. RESULTS: Based on the maximum docked score and minimum atomic contact energy, LPD-12 (-1137.38 kcal) was the appropriate molecule for proper binding with the S-glycoprotein of SARS-CoV-2 and thus significantly interrupted its affinity of binding with angiotensin-converting enzyme-2 (ACE2), which is the only receptor molecule found to be facilitating disease development. The results confirmed a strong binding affinity of LPD-12 with ACE2, with a binding free energy of -1621.62 kcal, which could also reciprocally prevent the binding of S-protein. CONCLUSTION: It can be concluded that LPD-12 may act as a potential therapeutic drug, by reducing the entry of SARS-CoV-2 to the human cells via the ACE2 receptor and related infections.

Bacteria and bacterial anticancer agents as a promising alternative for cancer therapeutics.

Cancer is the leading cause of deaths worldwide, though significant advances have occurred in its diagnosis and treatment. The development of resistance against chemotherapeutic agents, their side effects, and non-specific toxicity urge to screen for the novel anticancer agent. Hence, the development of novel anticancer agents with a new mechanism of action has become a major scientific challenge. Bacteria and bacterially produced bioactive compounds have recently emerged as a promising alternative for cancer therapeutics. Bacterial anticancer agents such as antibiotics, bacteriocins, non-ribosomal peptides, polyketides, toxins, etc. These are adopted different mechanisms of actions such as apoptosis, necrosis, reduced angiogenesis, inhibition of translation and splicing, and obstructing essential signaling pathways to kill cancer cells. Also, live tumor-targeting bacteria provided a unique therapeutic alternative for cancer treatment. This review summarizes the anticancer properties and mechanism of actions of the anticancer agents of bacterial origin and antitumor bacteria along with their possible future applications in cancer therapeutics.

Novel Compound from Flowers of Moringa oleifera Active Against Multi- Drug Resistant Gram-negative Bacilli.

BACKGROUND: The need for suitable antibacterial agents effective against Multi-drug resistant Gram-negative bacteria is acknowledged globally. The present study was designed to evaluate the possible antibacterial potential of an extracted compound from edible flowers of Moringa oleifera. METHODS: Five different solvents were used for preparing dried flower extracts. The most effective extract was subjected to fractionation and further isolation of the active compound with the highest antibacterial effect was obtained using TLC, Column Chromatography and reverse phase- HPLC. Approaches were made for characterization of the isolated compound using FTIR, NMR and Mass spectrometry. Antibacterial activity was evaluated according to the CLSI guidelines. RESULTS: One fraction of aqueous acetic acid extract of M. oleifera flower was found highly effective and more potent than conventional antibiotics of different classes against Multi-drug resistant Gram-negative bacilli (MDR-GNB) when compared. The phytochemical analysis of the isolated compound revealed the presence of hydrogen-bonded amine and hydroxyl groups attributable to unsaturated amides. CONCLUSION: The present study provided data indicating a potential for use of the flowers extract of M. oleifera in the fight against infections caused by lethal MDR-GNB. RECOMMENDATIONS: Aqueous acetic acid flower extract of M. oleifera is effective, in-vitro, against Gram-negative bacilli. This finding may open a scope in pharmaceutics for the development of new classes of antibiotics.

Self-Assembled Tea Tannin Graft Copolymer as Nanocarriers for Antimicrobial Drug Delivery and Wound Healing Activity.

Green chemistry polymers from renewable resources have recently received much more attention from pharmaceutical researchers. However, the appropriate application of a polymer depends on its chemical nature, biocompatibility and microstructure. Here, tannin polyphenols from the common beverage, tea, are used to develop a novel self-assembled porous capsule as a microstructure of hydrogel for versatile biological applications, such as drug delivery, antioxidant and wound healing activity. Hydrogel has been successfully used for the delivery of both anticancer and antimicrobial drugs. The developed material shows excellent biocompatibility and antioxidant activity in vitro. The scratch assay for in vitro wound healing activity reveals their higher potential to repair the damaged cells in comparison to control.

Phenolic Compounds in Antimicrobial Therapy.

Long-term treatment with several conventional antibiotics can cause harmful side effects that can be alleviated by antioxidant therapy. Phenolic compounds (PCs) are the best source of antioxidants, and to identify the most suitable polyphenols for use as a supportive supplement during antibiotic therapy, this study screened a series of PCs to establish their antibacterial potential, including their biofilm and ß-lactamase inhibition activity. Several PCs were tested for antibacterial activity against Staphylococcus epidermidis and Pseudomonas aeruginosa. Among them, tannic acid, epigallocatechin gallate, rutin, and eugenol showed the highest antibacterial activity. Epigallocatechin gallate, tannic acid, quercetin, and epicatechin inhibited a significant level of ß-lactamase activity. Tannic acid and epigallocatechin gallate presented the highest ß-lactamase inhibition potential in both in vitro and in silico analysis. In the present work, these two PCs were the most active agents, presenting both antibacterial activity and ß-lactamase and biofilm inhibition ability.

Screening of serine protease inhibitors with antimicrobial activity using iron oxide nanoparticles functionalized with dextran conjugated trypsin and in silico analyses of bacterial serine protease inhibition.

Plants produce a variety of proteins and peptides which are involved in their defense against pathogens. Serine protease inhibitors are a well-established class of inhibitors correlated with plant defense. Increased levels of protease inhibitors delay cell damage and expand the cell's life-span. Recently, the rapid emergence of antibiotic-resistant microbial pathogens has prompted immense interest in purifying novel antimicrobial proteins or peptides from plant sources. Usually, the purification of protease inhibitors is accomplished by salt-extraction, ultrafiltration and affinity chromatography. Here, we developed a novel approach based on iron oxide nanoparticles conjugated to dextran functionalized with trypsin beads that accelerate the quick screening and purification of antimicrobial peptides with serine protease inhibitor activity. The method described here also works for screening other inhibitors using particular protein kinases, and it is therefore a novel tool for use as the leading method in the development of novel antimicrobial agents with protease inhibitory activity. Finally, and no less important, molecular modelling and dynamics studies of a homologous inhibitor studied here with Escherichia coli trypsin and chymotrypsin are provided in order to shed some light on inhibitor-enzyme interactions.

Kaajal fights against eye pathogens and is safe for eye make-up: a reinvestigation of an ancient practice.

The present report includes a scientific view of the traditional use of 'Kaajal' from the leaf of Euphorbia neriifolia, an Indian spurge tree locally called the 'Monosha' plant. A thorough analysis of the material demonstrates that it contains carbon nanoparticles having two uniform sizes of 2-3 nm and 35-45 nm. Further study revealed that Kaajal has antimicrobial properties against eye pathogens and is biocompatible for cosmetic use.

The attack of the phytopathogens and the trumpet solo: Identification of a novel plant antifungal peptide with distinct fold and disulfide bond pattern.

Phytopathogens cause economic losses in agribusiness. Plant-derived compounds have been proposed to overcome this problem, including the antimicrobial peptides (AMPs). This paper reports the identification of Ps-AFP1, a novel AMP isolated from the Pisum sativum radicle. Ps-AFP1 was purified and evaluated against phytopathogenic fungi, showing clear effectiveness. In silico analyses were performed, suggesting an unusual fold and disulfide bond pattern. A novel fold and a novel AMP class were here proposed, the αß-trumpet fold and αß-trumpet peptides, respectively. The name αß-trumpet was created due to the peptide's fold, which resembles the musical instrument. The Ps-AFP1 mechanism of action was also proposed. Microscopic analyses revealed that Ps-AFP1 could affect the fungus during the hyphal elongation from spore germination. Furthermore, confocal microscopy performed with Ps-AFP1 labeled with FITC shows that the peptide was localized at high concentration along the fungal cell surface. Due to low cellular disruption rates, it seems that the main target is the fungal cell wall. The binding thermogram and isothermal titration, molecular dynamics and docking analyses were also performed, showing that Ps-AFP1 could bind to chitin producing a stable complex. Data here reported provided novel structural-functional insights into the αß-trumpet peptide fold.

Identification and characterization of a bactericidal and proapoptotic peptide from Cycas revoluta seeds with DNA binding properties.

Nowadays, novel pharmacies have been screened from plants. Among them are the peptides, which show multiple biotechnological activities. In this report, a small peptide (Ala-Trp-Lys-Leu-Phe-Asp-Asp-Gly-Val) with a molecular mass of 1,050 Da was purified from Cycas revoluta seeds by using reversed-phase liquid chromatography. This peptide shows clear deleterious effects against human epidermoid cancer (Hep2) and colon carcinoma cells (HCT15). It caused inhibition of cancer cell proliferation and further disruption of nucleosome structures, inducing apoptosis by direct DNA binding. A remarkable antibacterial activity was also observed in this same peptide. Nevertheless, no significant lysis of normal RBC cells was observed in the presence of peptide. Additionally, an acetylation at the N-termini portion is able to reduce both activities. Bioinformatics tools were also utilized for construction of a three-dimensional model showing a single amphipathic helix. Since in vitro binding studies show that the target of this peptide seems to be DNA, theoretical docking studies were also performed to better understand the interaction between peptide and nucleic acids and also to shed some light on the acetyl group role. Firstly, binding studies showed that affinity contacts basically occur due to electrostatic attraction. The complex peptide-ssDNA was clearly oriented by residues Ala(1), Lys(3), and Asp(6), which form several hydrogen bonds that are able to stabilize the complex. When acetyl was added, hydrogen bonds are broken, reducing the peptide affinity. In summary, it seems that information here provided could be used to design a novel derivative of this peptide which a clear therapeutic potential.

Enhanced production and partial characterization of an extracellular polysaccharide from newly isolated Azotobacter sp. SSB81.

A strain was selected by its highest extracellular polysaccharide (EPS) production ability compare to other isolates from the same rhizospheric soil. The selected strain was identified by 16S rDNA sequencing and designated as SSB81. Phylogenetic analysis of the gene sequence showed its close relatedness with Azotobacter vinelandii and Azotobacter salinestris. Maximum EPS (2.52 g l(-1)) was recovered when the basal medium was supplemented with glucose (2.0%), riboflavin (1 mg l(-1)) and casamino acid (0.2%). The EPS showed a stable viscosity level at acidic pH (3.0-6.5) and the pyrolysis temperature was found to be at 116.73 degrees C with an enthalpy (DeltaH) of 1330.72 J g(-1). MALDI TOF mass spectrometric result suggests that polymer contained Hex(5)Pent(3) as oligomeric building subunit. SEM studies revealed that the polymer had a porous structure with small pore size distribution indicating the compactness of the polymer. This novel EPS may find possible application as a polymer for environmental bioremediation and biotechnological processes.

Identification and structural insights of three novel antimicrobial peptides isolated from green coconut water.

Infections caused by pathogenic bacteria could cause an expressive negative impact on human health. A significant enhance in resistance to commercial antibiotics has been observed in all kinds of pathogenic bacteria. In order to find novel approaches to control such common infections, a wide number of defense peptides with bactericidal properties have been characterized. In this report, three peptides lower than 3kDa were purified and identified from green coconut (Cocos nucifera L.) water by using reversed phase-high performance liquid chromatography (HPLC), showing molecular masses of 858Da, 1249Da and 950Da. First one, named Cn-AMP1, was extremely efficient against both Gram-positive and Gram-negative bacteria, being MICs calculated for three peptides. All complete sequences were determined by MALDI-ToF analysis showing no identity in databanks. Moreover, peptide net charge and hydrophobicity of each peptide was in silico evaluated. Finally molecular modeling and dynamics were also applied generating peptides three-dimensional structures, indicating a better explanation to probable mechanisms of action. Cn-AMPs here reported show remarkable potential to contribute in the development of novel antibiotics from natural sources.