In the current study,Bacillus velezensisAG6 was isolated from sediment samples in the Red Sea, identified by traditional microbiological techniques and phylogenetic 16S rRNA sequences.

Passivated-carbon quantum dots (P-CQDs) have been attracting great interest as an antimicrobial therapy tool due to their bright fluorescence, lack of toxicity, eco-friendly nature, simple synthetic schemes, and possession of photocatalytic functions comparable to those present in traditional nanometric semiconductors. Besides synthetic precursors, CQDs can be synthesized from a plethora of natural resources including microcrystalline cellulose (MCC) and nanocrystalline cellulose (NCC). Converting MCC into NCC is performed chemically via the top-down route, while synthesizing CODs from NCC can be performed via the bottom-up route. Due to the good surface charge status with the NCC precursor, we focused in this review on synthesizing CQDs from nanocelluloses (MCC and NCC) since they could become a potential source for fabricating carbon quantum dots that are affected by pyrolysis temperature. There are several P-CQDs synthesized with a wide spectrum of featured properties, namely functionalized carbon quantum dots (F-CQDs) and passivated carbon quantum dots (P-CQDs). There are two different important P-CQDs, namely 2,2′-ethylenedioxy-bis-ethylamine (EDA-CQDs) and 3-ethoxypropylamine (EPA-CQDs), that have achieved desirable results in the antiviral therapy field. Since NoV is the most common dangerous cause of nonbacterial, acute gastroenteritis outbreaks worldwide, this review deals with NoV in detail. The surficial charge status (SCS) of the P-CQDs plays an important role in their interactions with NoVs. The EDA-CQDs were found to be more effective than EPA-CQDs in inhibiting the NoV binding. This difference may be attributed to their SCS as well as the virus surface. EDA-CQDs with surficial terminal amino (-NH₂) groups are positively charged at physiological pH (-NH³⁺), whereas EPA-CQDs with surficial terminal methyl groups (-CH₃) are not charged. Since the NoV particles are negatively charged, they are attracted to the positively charged EDA-CQDs, resulting in enhancing the P-CQDs concentration around the virus particles. The carbon nanotubes (CNTs) were found to be comparable to the P-CQDs in the non-specific binding with NoV capsid proteins, through complementary charges, π-π stacking, and/or hydrophobic interactions.

Quorum sensing inhibitor (QSI) has been attracting attention as anti-virulence agent which disarms pathogens of their virulence rather than killing them. QSI marking cyclic peptide-mediated QS in Gram-positive bacteria is an effective tool to overcome the crisis of antibiotic-dependent chemotherapy due to the emergence of drug resistance strain, e.g., methicillin resistant Staphylococcus aureus (MRSA) and Vancomycin resistant Enterococci (VRE). From a semi-large-scale screening thus far carried out, two Epoxide compounds, Ambuic acid and Synerazol, have been found to efficiently block agr and fsr QS systems, suggesting that the Epoxide group is involved in the mode of action of these QSIs. To address this notion, known natural Epoxide compounds, Cerulenin and Fosfomycin were examined for QSI activity for the agr and fsr systems in addition to in silico and SAR studies. As a result, most of investigated Epoxide containing antibiotics correlatively interfere with QSI activity for the agr and fsr systems under sublethal concentrations.

Microbial exopolysaccharides (EPSs) are gaining interest as alternatives to chemical antioxidants and pharmaceuticals. This study mines the promising biomedical and antimicrobial potential of a marine bacterium, a prolific EPS producer, isolated from the Red Sea. Pseudomonas sp. strain AHG22 generated an EPS weighing 6.98 g·L⁻¹, coded EPSF8, subjected to FT-IR and HPLC chemical analysis. EPSF8 was then investigated for antioxidant assessment by 2,2-diphenyl-1-picrylhydrazyl (DPPH), H₂O₂, ABTS˙ ⁺ , nitric oxide, total antioxidant capacity (TAC), and ferric reducing antioxidant power (FRAP). EPSF8 had an IC₅₀ of 46.99 μg·mL⁻¹ in the DPPH antioxidant assay and antioxidant capacities of 219.45 μg·mg⁻¹ ascorbic acid equivalent (AAE) in the TAC assay and 54.15 μg·mg⁻¹ AAE in the FRAP assay. The in vitro anti-inflammatory effect of EPSF8 was tested against 5-lipoxygenase (5-LOX) and cyclooxygenase-2 (COX-2) enzymes and compared with the drugs ibuprofen and celecoxib used as controls. The IC₅₀ values of 5-LOX, COX-2, ibuprofen, and celecoxib were found to be 14.82, 15.49, 1.5, and 0.28 μg·mL⁻¹, respectively. Additionally, EPSF8 revealed antidiabetic activity toward α-amylase and α-glucosidase, and the IC₅₀ values were 93.1 and 127.28 μg·mL⁻¹, compared to those of acarbose (50.93 and 4.13 μg·mL⁻¹, respectively). Anti-obesity activity of EPSF8 by lipase inhibition revealed IC₅₀ = 56.12 μg·mL⁻¹ compared to orlistat (IC₅₀ = 20.08 μg·mL⁻¹) as a control. EPSF8 displayed antibiofilm and bactericidal activity against Gram-positive (G +ve) and Gram-negative (G −ve) ATCC pathogenic bacterial strains. It had a minimum bactericidal concentration/minimum inhibitory concentration ratio ≤2, indicating a broad bactericidal spectrum. Furthermore, EPSF8 is evidenced to have a promising anti-butyrylcholinesterase activity for the control of Alzheimer’s disease. The findings of the present analysis suggest that the isolated Pseudomonas sp. strain AHG22 EPS can potentially be explored as a promising green therapeutic compound.

Introduction: Exopolysaccharides (EPSs) derived from marine microorganisms are a newly recognized reservoir of bioactive therapeutic compoundsMaterial and methods: We isolated a high EPS-yielding bacterial strain from the Red Sea, identified as Bacillus rugosus SYG20. Its purified EPS (EPSR9) contains 45.33% uronic acid, 9.98% sulfate groups, and 5.40% N-acetyl glucosamine. The HPLC chromatogram revealed four monosaccharides - glucose, xylose, galacturonic acid, and arabinose, in a distinct molar ratio of 2:3:1:1. EPSR9 showed a wide array of bioactivities.Results: It displayed antioxidant activity with an IC50 of 25.6 μg/ml in the DPPH assay and a total antioxidant capacity (TAC) of 417.77μg/ml equivalent AAE and 62.67 μg/ml equivalent AAE in Ferric reducing antioxidant power (FRAP) assays. It exhibited substantial anti-inflammatory properties. The anticoagulant effect of the EPS was demonstrated by a dose-dependent increase in prothrombin time. The scratch assay resulted in a 72.66% increase in wound closure, promoting in vitro wound healing after 48 h. Anti-obesity activity was evidenced by 83.8% lipase inhibition at 1000 μg/ml with IC50 of 107.73μg/ml. EPSR9 demonstrated inhibitory effects on α-amylase with an IC50 value of 14.37μg/ml and α-glucosidase with an IC50 value of 26.73 μg/ml, highlighting its potential as an anti-diabetic agent. Then, EPS showed bactericidal properties with MBC/MIC≤2 against both G+ve and G-ve bacteria, Staphylococcus aureus , Enterococcus faecalis (MIC=3.9μg/ml), Salmonella typhi, and Helicobacter pylori.Conclusions: The marine EPSR9 exhibited considerable potential for pharmaceutical applications as a multi-bioactive microbial metabolite. Its in vivo potency and mechanisms of action warrant further investigation.

Every minute, the world’s population grows, and in order to feed them, crop output and agricultural productivity must be improved by adding crucial microorganisms that boost plant yields in various ways through nitrogen fixation, the secretion of both plant growth regulators and 1-aminocyclopropane 1-carboxylate deaminase, as well as some antimicrobial agents. Numerous endophytic bacteria have recently been used to increase plant yields, and agricultural production in addition to reducing salt stresses. Many scientists have made an effort to clarify and comprehend the processes by which bacteria promote plant growth and production. A vital substance known as 1-aminocyclopropane-1-carboxylate (ACC) deaminase is produced by several bacteria, plants, and fungi to decrease ethylene levels in a plant grown under different environmental stress. The gaseous hormone ethylene (C2H4) is synthesized in plant tissues from the precursor ACC, and it has numerous biochemical roles in plants, such as cells differentiation and tissue development, seedling, root hair, leaf, and flower growth and development in addition to fruit ripening and formation of anthocyanin and volatile compounds. Thus, this critical enzyme had influential roles in plants during their positive interaction with bacteria which increase plant growth due to auxin production and protect plants against different environmental stress like drought, high salts, wilting, high level of heavy metals, contaminants with pesticides, and microbial pathogen infections. Different bacterial genera are highly ACC deaminase-producer, and these bacteria support plant growth and agricultural process. In conclusion, bacteria can replace chemicals in a variety of environmentally benign methods to boost soil fertility and plant productivity. However, much research is required to determine the efficacy of these bacteria before suggesting their use on a broad scale in the field.