Concentration-dependent Activity Research Articles

Comprehensive Extraction and Biological Activities of Mycosporine-like Amino Acids and Glyceroglycolipids Extracts from Two Macroalgae Ecklonia kurome and Ulva lactuca

Mycosporine-like amino acids (MAAs) and glyceroglycolipids have promising applications in various fields, but limited research exists on their simultaneous extraction from macroalgae. This study optimized the key parameters (liquid–solid ratio, extraction temperature and extraction time) in the extraction of MAAs and glyceroglycolipids from Ecklonia kurome and Ulva lactuca using single factor and response surface experiments. The yields of MAAs from E. kurome and U. lactuca were 169.71 mg/g and 177.33 mg/g, respectively, while glyceroglycolipids were extracted from the residue with yields of 163.51 mg/g and 213.45 mg/g, respectively. Both extracts showed concentration-dependent antioxidant activities, with the MAAs extracted from U. lactuca demonstrating the strongest effect. The addition of MAA extract to flaxseed oil significantly reduced oxidation rancidity, highlighting its potential as a natural antioxidant for oils. The glyceroglycolipid extract from E. kurome exhibited significant moisture absorption, and a water-retaining agent prepared from this extract showed excellent moisture retention and resistance to high temperatures, freezing, and pressure. A silica gel column chromatography method confirmed the presence of MGDG in the purified glyceroglycolipid extract. These findings suggested that E. kurome and U. lactuca can be converted into high-value-added compounds with potential applications in food, cosmetics, and pharmaceuticals.

Antifungal activity of traversianal, a diterpenoid aldehyde from Cercospora sp. ME202, against the rice blast fungus, Pyricularia oryzae

Abstract Here, we evaluated the antifungal activity of traversianal, a diterpenoid derived from Cercospora sp. ME202, against Pyricularia oryzae, which causes rice blast. Traversianal had concentration-dependent inhibitory activity against conidial germination and inhibited hyphal growth in a TLC bioassay. Staining conidia for viability with fluorescein diacetate and propidium iodide showed that the fungicidal activity was associated with cell membrane damage over time. Pretreatment of rice leaves with traversianal before inoculation decreased the number of blast lesions. These results suggest that traversianal has potential for controlling rice blast.

Targeting InhA in drug-resistant Mycobacterium tuberculosis: potent antimycobacterial activity of diaryl ether dehydrozingerone derivatives.

Tuberculosis (TB) remains a major global threat, with 10 million new cases and 1.5 million deaths each year. In multidrug-resistant tuberculosis (MDR-TB), resistance is most commonly observed against isoniazid (INH) and rifampicin (RIF), the two frontline drugs. Isoniazid resistance is predominantly linked to mutations in the InhA gene, which encodes an enzyme involved in mycolic acid synthesis, a vital component of the mycobacterial cell wall. Mutations in InhA reduce drug binding, rendering INH ineffective. These morbidity and mortality figures, along with the fact that the rise and global spread of drug-resistant TB, underscores the need for the discovery of novel therapeutics. In this direction, we have previously synthesized, characterized, and screened a library of diaryl ether dehydrozingerone derivatives against mycobacteria and identified two best hits, 7 and 14, based on bacteriostatic activities. The present study aimed to thoroughly investigate the antituberculosis potential of these compounds, particularly regarding drug-resistant TB. Our findings revealed that both compounds exhibited tuberculocidal activity against the standard laboratory strain Mycobacterium tuberculosis (M. tb) H37Rv, with minimal bactericidal concentrations (MBC) of 4μg/ml for compound 7 and 8μg/ml for compound 14. Next, concentration vs time-kill kinetics of both these compounds showed concentration-dependent bactericidal activities against M. tb and complete pathogen eradication from culture at just 16× MIC. Both compounds were found to be suitable for combination regimens as their interactions with isoniazid and rifampicin against M. tb were observed to be synergistic. Additionally, 7 and 14 exhibited minimal hemolysis against human RBCs and less cytotoxicity was observed against three human cell lines up to 1000μM. Molecular docking revealed that these compounds bind more effectively to M. tb InhA, including its mutant forms where isoniazid binding is impaired, outperforming both isoniazid and triclosan in binding affinity. Importantly 7 and 14 showed potent activity against drug-susceptible clinical isolates and two isoniazid-resistant M. tb clinical isolates equivalent to that against M. tb H37Rv. The most interesting observation was that both compounds were found to be effective against three multi-drug resistant (MDR) strains of M. tb, thereby depicting their potential against drug-resistant TB. An ex vivo assay on RAW 264 cells infected with M. tb demonstrated a significant reduction in bacterial load at 8× MIC, revealing the fact that these compounds are highly effective against intracellular M. tb H37Rv. To the best of our knowledge, this is the first study that reports promising antimycobacterial potential of 7 and 14 against drug-susceptible, isoniazid-resistant, and MDR tuberculosis which warrants further exploration considering the need for new anti-TB medicine.

Polyproline-Polyornithine Diblock Copolymers with Inherent Mitochondria Tropism.

Mitochondria play critical roles in regulating cell fate, with dysfunction correlating with the development of multiple diseases, emphasizing the need for engineered nanomedicines that cross biological barriers. Said nanomedicines often target fluctuating mitochondrial properties and/or present inefficient/insufficient cytosolic delivery (resulting in poor overall activity), while many require complex synthetic procedures involving targeting residues (hindering clinical translation). The synthesis/characterization of polypeptide-based cell penetrating diblock copolymers of poly-L-ornithine (PLO) and polyproline (PLP) (PLOn-PLPm, n:m ratio 1:3) are described as mitochondria-targeting nanocarriers. Synthesis involves a simple two-step methodology based on N-carboxyanhydride ring-opening polymerization, with the scale-up optimization using a "design of experiments" approach. The molecular mechanisms behind targetability and therapeutic activity are investigated through physical/biological processes for diblock copolymers themselves or as targeting moieties in a poly-L-glutamic (PGA)-based conjugate. Diblock copolymers prompt rapid cell entry via energy-independent mechanisms and recognize mitochondria through the mitochondria-specific phospholipid cardiolipin (CL). Stimuli-driven conditions and mitochondria polarization dynamics, which decrease efficacy depending on disease type/stage, do not compromise diblock copolymer uptake/targetability. Diblock copolymers exhibit inherent concentration-dependent anti-tumorigenic activity at the mitochondrial level. The diblock copolymer conjugate possesses improved safety, significant cell penetration, and mitochondrial accumulation via cardiolipin recognition. These findings may support the development of efficient and safe mitochondrial-targeting nanomedicines.

Phytochemical analysis and anti-aging efficacy of two Egyptian sweet potato cultivars in a d-galactose-induced skin aging model

BackgroundSweet potato (Ipomoea batatas (L.) Lam.) is a member of the family Convolvulaceae. Much research has highlighted its variable biological actions in the treatment of many disorders. Our study focused on the quantitative analysis of two Egyptian sweet potato cultivars (Abees and A195). First, we applied proximate analysis, measured total phenolic, and flavonoid contents, performing an HPLC standardization of their ethanolic extracts using chlorogenic acid standard. Furthermore, the two cultivars were formulated as topical creams (3% w/w and 5% w/w) and evaluated for their anti-skin aging activity in a d-galactose-induced skin aging mouse model. Results revealed that both cultivars have high nutritional importance.ResultsAbees exhibited higher total phenolic and flavonoid contents than A195, while A195 contained a higher concentration of chlorogenic acid. Both cultivars showed a concentration-dependent anti-skin aging activity, with 5% Abees cream demonstrating the lowest visual skin-aging score, the highest activity of catalase (CAT) and superoxide dismutase (SOD), and the lowest concentration of malondialdehyde (MDA). Restoration of skin thickness and collagen content was observed in the 5% Abees group, while both Abees and A195 caused a noticeable concentration-dependent decrease in the skin SMAD7 expression. Decreased SMAD7 has been correlated to upregulating the TGF-β/SMAD3-induced collagen production in aged skin.ConclusionThis study elaborates the nutritional importance, phenolic and flavonoid content and anti-skin aging activity of Abees and A195 roots and we recommend further preclinical and clinical investigations of sweet potato.

Bicarbonate, calcium ions, hydrogen peroxide and trypsin modulate activation of Anopheles gambiae sperm motility and protein tyrosine phosphorylation.

With the increasing concern of potential loss of transgenic mosquitoes which are candidates as new tools for mosquito-borne disease control, methods for cryopreservation are actively under investigation. Methods to cryopreserve Anopheles gambiae sperm have recently been developed, but there are no artificial insemination or in vitro fertilization tools available. As a step to achieve this, we sought to identify a suitable medium for in vitro incubation of An. gambiae sperm and to tease out critical components that are involved in the sperm motility activation process. Using two cell viability assays, we identified the Biggers-Whitten-Whittingham (BWW) medium as suitable for in vitro incubation of An. gambiae sperm isolated from testes. We then modified the medium for motility assays by testing different HCO3- and Ca2+ concentrations. Our results show that there is an HCO3- and Ca2+ concentration-dependent activation of An. gambiae sperm motility. We further demonstrated that H2O2 can be produced by the testes in vitro and that the addition of 5.3 μM of H2O2 to the medium improves sperm motility and increases protein tyrosine phosphorylation in An. gambiae. Finally, we show a dose-dependent activation of sperm motility by the addition of trypsin to the medium and more than a 2-fold increase in sperm motility when modified BWW (mBWW) medium is supplemented with H2O2 and trypsin. Our in vitro results suggest that protein tyrosine phosphorylation, intracellular ionic influx, intrinsic production of H2O2 and trypsin-like proteases play a vital role in signal transduction that leads to the activation of An. gambiae sperm motility.

Flavonoids and other constituents from Jacaranda mimosifolia: In vitro analysis, molecular docking, and molecular dynamic simulations of antioxidant and anti-inflammatory activities.

The investigation of the methanol extract of the flowers of Jacaranda mimosifolia led to the isolation and characterisation of fourteen secondary metabolites (1-14) by the means of chromatographic and spectroscopic analysis. These compounds include eight flavonoids sorted as two flavonols (1-2), three flavones (3, 7-8), and three isoflavones (4, 9-10), two glucoiridoids (5-6), and four triterpenoids sorted as one oleanane (11), one hopane (12), and two lupane (13-14). The in vitro antioxidant potential of all the isolated compounds was evaluated using the ABTS- and FRAP- methods, which demonstrated concentration-dependent activity. Chloroflavonin A (1) and 4',5,7-trihydroxyflavone (2) demonstrated exceptional antioxidant activity, with scavenging rates of 98.63 % and 97.89 %, respectively, at a concentration of 300 μg/mL, and also showed strong ferric-reducing antioxidant power. Chloroflavonin A (1) demonstrated the most potent dual inhibitory effects on Cyclooxigenase-2 (COX-2) and NADPH-Oxidase-5 (NOX-5) enzymes, with binding affinities of -9.7 and -8.2 kcal/mol, respectively, indicating its potential as a strong anti-inflammatory compound. The molecular dynamics simulation, conducted with the Desmond v3.6, demonstrated the stability of the various complexes within the biological system. The findings indicate that compounds derived from Jacaranda mimosifolia may serve as potential therapeutic agents for the management of inflammation and oxidative stress.

Study on the suitability of disinfectants using concentration-dependent antibacterial activity of Saccharinajaponica, Centella asiatica and Bamboo leave, extracts

Study on the suitability of disinfectants using concentration-dependent antibacterial activity of Saccharinajaponica, Centella asiatica and Bamboo leave, extracts

Design, Synthesis and Biological Evaluation of Ethyl 5-(1-benzyl-1H-indol-5-yl) Isoxazole-3-Carboxylates as Antimycobacterial Agents.

The continued prevalence of drug-resistant Mycobacterium tuberculosis (Mtb) strains, particularly against first-line antitubercular (anti-TB) drugs, presents an impending public health threat that necessitates the exploration and development of New Chemical Entities (NCEs). In search of new anti-TB leads, a library of ethyl 5-(1-benzyl-1H-indol-5-yl) isoxazole-3-carboxylates were generated through a strategy of scaffold hopping from the proven isoxazole-3-carboxylate-based anti-TB pharmacophore. We evaluated their antibacterial potential against a panel of pathogenic bacteria and Mtb H37Rv strains. The majority of the compounds exhibited notable in vitro efficacy against the H37Rv strains (MIC 0.25 to 16 μg/mL) and were not cytotoxic with a Selectivity Index (SI) >10. Compound 5e (3,4-dichlorobenzyl substituent) was found to be optimally active in the lot (MIC 0.25 μg/mL) and SI >200. It also displayed equipotent activity against drug-resistant Mtb (DR-Mtb) strains. In addition, it demonstrated concentration-dependent bactericidal activity in a time-kill kinetic assay similar to first-line anti-TB drugs besides exhibiting synergistic activity with Streptomycin. Moreover, it complies with the drug-likeness characteristic, making it a promising candidate for further exploration as a probable anti-TB lead.

Recombinant Anti-PF4 Antibodies Derived from Patients with Vaccine-Induced Immune Thrombocytopenia and Thrombosis (VITT) Facilitate Research and Laboratory Diagnosis of VITT.

Adenoviral vector-based vaccines against COVID-19 rarely cause vaccine-induced immune thrombocytopenia and thrombosis (VITT), a severe adverse reaction caused by IgG antibodies against platelet factor 4 (PF4). To study VITT, patient samples are crucial but have become a scarce resource. Recombinant antibodies (rAbs) derived from VITT patient characteristic amino acid sequences of anti-PF4 IgG are an alternative to study VITT pathophysiology. Amino acid sequences of the variable region of immunoglobulin light and heavy chain of anti-PF4 IgG derived from VITT patients were obtained by mass spectrometry sequencing and rAbs were synthetized by reverse-engineering. Six different rAbs were produced: CR23003, CR23004, and CR23005 (from a patient vaccinated with Jcovden, Johnson & Johnson-Janssen (Beerse, Belgium)), CR22046, and CR22050 and CR22066 (from two different patients vaccinated with Vaxzevria, AstraZeneca (Cambridge, UK)). These rAbs were further characterized using anti-PF4 and anti-PF4/heparin IgG ELISAs, rapid anti-PF4 and anti-PF4/polyanion chemiluminescence assays, and PF4-induced platelet activation assay (PIPA) and their capacity to induce procoagulant platelets. rAbs bound to PF4 alone, but not to PF4/polyanion complexes in rapid chemiluminescence assays. Chemiluminescence assays and both anti-PF4 IgG and anti-PF4 IgG/heparin ELISA showed concentration-dependent PF4 binding of all six rAbs, however, with different reactivities among them. PIPA showed a similar, concentration-dependent platelet activation pattern. rAbs varied in their reactivity and the majority of the tested rAbs were able to induce procoagulant platelets. The six rAbs derived from VITT patients reflect VITT-typical binding capacities and the ability to activate platelets. Therefore, these rAbs offer an attractive new option to study VITT pathophysiology.

New Insights on Gordonia alkanivorans Strain 1B Surface-Active Biomolecules: Gordofactin Properties

Biosurfactants/bioemulsifiers (BSs/BEs) can be defined as surface-active biomolecules produced by microorganisms with a broad range of applications. In recent years, due to their unique properties like biodegradability, specificity, low toxicity, and relative ease of preparation, these biomolecules have attracted wide interest as an eco-friendly alternative for several industrial sectors, escalating global microbial BS/BE market growth. Recently, Gordonia alkanivorans strain 1B, a bacterium with significant biotechnological potential, well known for its biodesulfurizing properties, carotenoid production, and broad catabolic range, was described as a BS/BE producer. This study focuses on the characterization of the properties of the lipoglycopeptide BSs/BEs produced by strain 1B, henceforth referred to as gordofactin, to better understand its potential and future applications. Strain 1B was cultivated in a chemostat using fructose as a carbon source to stimulate gordofactin production, and different purification methods were tested. The most purified sample, designated as extracted gordofactin, after lyophilization, presented a specific emulsifying activity of 9.5 U/mg and a critical micelle concentration of 13.5 mg/L. FT-IR analysis revealed the presence of basic hydroxyl, carboxyl, ether, amine/amide functional groups, and alkyl aliphatic chains, which is consistent with its lipoglycopeptide nature (60% lipids, 19.6% carbohydrates, and 9% proteins). Gordofactin displayed remarkable stability and retained emulsifying activity across a broad range of temperatures (30 °C to 80 °C) and pH (pH 3–12). Moreover, a significant tolerance of gordofactin emulsifying activity (EA) to a wide range of NaCl concentrations (1 to 100 g/L) was demonstrated. Although with a great loss of EA in the presence of NaCl concentrations above 2.5%, gordofactin could still tolerate up to 100 g/L NaCl, maintaining about 16% of its initial EA for up to 7 days. Furthermore, gordofactin exhibited growth inhibition against both Gram-positive and Gram-negative bacteria, and it demonstrated concentration-dependent free radical scavenging activity for 2,2-diphenyl-1-picrylhydrazyl (IC50 ≈ 1471 mg/L). These promising features emphasize the robustness and potential of gordofactin as an eco-friendly BS/BE alternative to conventional surfactants/emulsifiers for different industrial applications.

Evaluation of Anti-oxidant and Anti-bacterial effects of Resveratrol Enriched Polyphenols from Peanut Skin

The purpose of this study was to assess the antibacterial and antioxidant activities of resveratrol-enriched polyphenols extracted from peanut skin (PFP). High-Performance Liquid Chromatography (HPLC), Fourier-Transform Infrared Spectroscopy (FT-IR) and UV–Vis spectroscopy were used to analyse the chemical composition of PFP. Antioxidant activity was assessed through various in vitro assays, including DPPH, FRAP, NO, and ABTS. The agar well diffusion method was used to assess the antibacterial properties. The results demonstrated that PFP exhibited concentration-dependent antioxidant activity in all tested assays, with significant activity observed in the DPPH, FRAP, ABTS, and NO assays. Additionally, PFP showed substantial antibacterial activity, particularly against Methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus aureus, as evidenced by larger inhibitory zones. The polyphenolic content of PFP was measured at 75 mg GAE/g, with resveratrol enrichment confirmed through chemical characterization. These findings suggest that PFP, derived from a low-value byproduct of peanut processing, is a potent source of bioactive compounds with significant antioxidant and antibacterial properties. Hence, it can be used as an alternative source for the development of new drugs.

TAXONOMIC DESCRIPTION AND ANTIBACTERIAL ACTIVITY OF DILLENIA sp. AGAINST ESCHERICHIA coli

Article Highlights- The study first reported taxonomic study of Dillenia sp. in Malita, Davao, Occidental Philippines. - This is the first reported findings of the bacterial activity of the bark extract of Dillenia sp. against Escherichia coli. AbstractThe study aimed to provide a taxonomic description of Dillenia sp. and evaluate its antibacterial activity against Escherichia coli (E. coli). The taxonomic description was characterized using the taxonomic keys and field guides. The antibacterial activity of Dillenia sp. was screened using the Kirby-Bauer disk diffusion assay. Taxonomic description confirms Dillenia sp. to be an angiosperm flowering seed plant native to the Philippines, characterized by its round-shaped growth and evergreen foliage. The antibacterial activity of Dillenia sp. bark extracts against E. coli were assessed using different concentrations (100 ppm, 500 ppm, and 1000 ppm) and extraction solvents (ethanolic, aqueous, and decoction). There are significant differences in the antibacterial activity observed among treatments within the decoction extracts, indicating varying effects on antibacterial activity. Post-hoc analysis revealed that concentrations of 100 ppm and 500 ppm were significantly more effective in inhibiting bacterial growth compared to 1000 ppm within the Decoction treatment. Each treatment showed distinct patterns of antibacterial activity, with ethanolic and aqueous extracts displaying relatively consistent activity across different concentrations, while the decoction extract exhibited concentration-dependent antibacterial activity. The study provides evidence of the antibacterial potential of Dillenia sp. bark extracts against Escherichia coli, with implications for further research and potential practical applications in combating bacterial infections. Recommendations include exploring different lower concentration ranges, considering different treatment formulations, investigating combination treatments, and assessing antimicrobial mechanisms to enhance efficacy and guide the development of novel antibacterial strategies.

Evaluation of pharmacognostic, phytochemical, antioxidant and anticancer properties of leaves of <i>Cassia tora</i> and <i>Mimusops elengi</i>

The objective of the present research work was to study the selected medicinal plants regarding their botanical, phytomoieties present, free radical scavenging, and antineoplastic properties of the alcoholic extract of leaves from Mimusops elengi (MEAE) and Cassia tora (CTAE). An attempt was also made to compare the results obtained with proven anticancer marker compounds like Curcumin, Quercetin, Gallic acid, and Ursolic acid. Pharmacognostic studies were conducted using standard methods and protocols. Phytochemical analysis was performed using HPTLC studies. The antioxidant potential of selected plant extracts has been evaluated using a DPPH assay. The selected activity was evaluated using a sensitive and reliable MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay towards MCF-7 (breast), HeLa (Cervical), and HepG2 (liver) cells. Self-programmed Cell death or Apoptosis assay was carried out on MCF-7 cancer cells to explore the possible mechanism of the anticancer effect of these plant extracts. Pharmacognostic evaluations confirmed the identity, quality, and safety of the botanical specimens used. HPTLC analysis revealed distinct phytochemical profiles rich in Gallic acid, Quercetin, Ursolic acid, and similar compounds in both extracts. The study demonstrated concentration-dependent antioxidant activity with MEAE exhibiting stronger activity than CTAE. The results thus obtained in the MTT assay exhibited that cancer cell multiplication of MCF-7, HeLa, and HepG2 cancer cells was prevented by the selected extracts of MEAE and CTAE in a reproducible dose-dependent manner over time. Results of the Apoptosis assay gave the authors a probable thought and direction, that the anticancer activity of CTAE and MEAE towards MCF-7 breast cancer cells may be due to induction of apoptosis.

Pseudoalteromonas flavipulchra as a dual-functional probiotic for aquaculture: enhancing microalgae growth and antagonizing Vibrio pathogens

Vibrio disease is a prevalent bacterial infection in aquaculture, and using bacteria with antagonistic properties against Vibrio species as probiotics has emerged as a promising method for disease prevention. Additionally, low biomass productivity of microalgae feed remains a significant bottleneck in bivalve aquaculture. Therefore, it is essential to screen for bacteria that both enhance microalgae growth and inhibit Vibrio pathogens. In this study, seven bacterial strains capable of promoting microalgae growth were screened for their ability to inhibit three Vibrio pathogens, i.e., Vibrio vulnificus, Vibrio parahaemolyticus and Vibrio cholerae, and thus serve as a dual-functional probiotic for aquaculture. The antagonistic mechanism of these bacteria was further investigated by analyzing the inhibitory effects of their extracellular products (ECP) on Vibrio species. Results indicated that Pseudoalteromonas flavipulchra exhibited antagonistic effects against all three Vibrio species tested. The ECP of P. flavipulchra displayed stable antibacterial activity, though this ability was lost after the ECP was treated with heat, alkali, or proteinase K. The proteinaceous fraction isolated from the ECP by precipitation with 90% saturated ammonium sulfate demonstrated concentration-dependent antibacterial activity. These findings suggest that P. flavipulchra could serve as a promising dual-functional probiotic for aquaculture, warranting further research to optimize its application in this field.

Conjugation of Polycationic Peptides Extends the Efficacy Spectrum of β-Lactam Antibiotics.

Antibiotic-resistant enterococci represent a significant global health challenge. Unfortunately, most β-lactam antibiotics are not applicable for enterococcal infections due to intrinsic resistance. To extend their antimicrobial spectrum, polycationic peptides are conjugated to examples from each of the four classes of β-lactam antibiotics. Remarkably, the β-lactam-peptide conjugates gained an up to 1000-fold increase in antimicrobial activity against vancomycin-susceptible and vancomycin-resistant enterococci. Even against β-lactam-resistant Gram-negative strains, the conjugates are found to be effective despite their size exceeding the exclusion volume of porins. The extraordinary gain of activity can be explained by an altered mode of killing. Of note, the conjugates showed a concentration-dependent activity in contrast to the parent β-lactam antibiotics that exhibited a time-dependent mode of action. In comparison to the parent β-lactams, the conjugates showed altered affinities to the penicillin-binding proteins. Furthermore, it is found that peptide conjugation also resulted in a different elimination route of the compounds when administered to rodents. In mice systemically infected with vancomycin-resistant enterococci, treatment with a β-lactam-peptide conjugate reduced bacterial burden in the liver compared to its originator. Therefore, peptide modification of β-lactam antibiotics represents a promising platform strategy to broaden their efficacy spectrum, particularly against enterococci.

Anti-quorum sensing and anti-biofilm activities of Pasteurella multocida strains

A total of 52 Pasteurella multocida strains of capsular serogroups (A, B and D) were screened for anti-quorum sensing activity against Chromobacterium violaceum. Of which, 12 strains of serogroups A were found to possess anti-quorum sensing activity. Inhibition activity was highest for strain NIVEDIPm9 and lowest for strain NIVEDIPm30 based on zone of pigment inhibition. Further, cell free extract of NIVEDIPm9 strain showed highest anti-biofilm activity in reference E. coli strain and concentration dependent degradation activity of C6-AHL molecule. In whole genome sequence annotation of NIVEDIPm9 strain predicted the presence of four metallo-β-lactamases (MBL) fold metallo-hydrolase proteins. In docking studies, MBL1 and MBL3 proteins showed high binding affinity with autoinduce signalling molecules AHL compound of OH-C10, binding energy value were −6.3 and −6.2 kcal/mol. Interaction study of VAF and quorum sensing molecules showed that OmpA and HgbA proteins were stimulated by all the ten molecules (C4-AHLs, C6-AHLs, C10-AHLs, C14-AHLs, 3-oxo-C10-AHLs, 3OH-C10-HSL, C8-HSL, C10-HSL, C12-HSL, C14-HSL), while toxA gene was stimulated by OH-C10-AHL molecule, sodC gene was stimulated by none. In conclusion, we described the anti-quorum sensing activities of diverse P. multocida strains causing Pasteurellosis in livestock.

Assessment of Lethal, Sublethal, Transgenerational, and Biochemical Effects of Isaria fumosorosea on Mythimna separata.

Mythimna separata is a destructive polyphagous pest of field crops. Insecticides are generally applied for its control which not only negatively affect natural enemies and the environment and cause resistance in the insect pests. There is a need for the friendly method which is safe for the environment and life. Currently, entomopathogenic fungi are being used as biological control agents for different insects. The influence of Isaria fumosorosea on survival, life table parameters, and enzymatic activities of M. separata were assessed. On the seventh day post-treatment, the highest concentration 3 × 108 spores/mL-1 caused the 92.5% larval mortality. The effect of LC15 and LC50 of I. fumosorosea were recorded on parental generation (F0) and first filial generation (F1) of M. separata. The life table parameters of F1 showed a decreasing trend in the intrinsic rate (r), net reproductive rate (Ro), mean generational time (T), total larval duration, and fecundity ratio in treated groups. In LC15 and LC50, groups the average fecundity ratio was 319.2 and 191.18 eggs/female, respectively. The activities of detoxifying enzymes were concentration-dependent and highest activities were recorded on the third day. I. fumosorosea negatively affected the growth parameters of M. separata and can be included in M. separata management program.

Structural characterization, antioxidant activities and physicochemical properties analysis of a galactose-rich exopolysaccharide produced by Limosilactobacillus fermentum YL-11

Lactobacilli-derived exopolysaccharides (EPSs) are widely regarded as safe and have been employed as potential natural, non-toxic additives and functional agents in food industry. The structural properties of a galactose-rich exopolysaccharide produced by Limosilactobacillus fermentum YL-11 (YL-11 EPS) were investigated with chemical and instrumental analysis. The YL-11 EPS was determined to have a molecular weight (Mw) of 13.2 kDa. Nine different types of glycosidic bonds were identified in YL-11 EPS. The inferred structure of the YL-11 EPS contained the backbone of →2)-β-D-Galp-(1→[3)-β-D-Galp-(1]4 → 3)-β-D-Galp-(1 → 3)-β-D-Galp-(1→, with two side chains, β-D-Galp-(1 → 6)-α-D-Manp-(1 → 6)-[α-D-Glcp-1→2]-α-D-Manp-(1 → 3)-[α-D-Glcp-1→6]-α-D-Glcp-(1 → 3)-[α-D-Glcp-1→6]-α-D-Glcp-(1→ with an acetyl group at the O-3 position of →2,6-α-D-Manp-1→ and α-L-Araf-(1→, which were present at the C6 location of the 1,3-β-D-Galp. The YL-11 EPS showed concentration-dependent antioxidant activities and the DPPH, ABTS, hydroxyl groups and superoxide radicals scavenging rates of 10 mg/mL YL-11 EPS reached 61%, 74%, 35.4% and 40%, respectively. The YL-11 EPS also has a beneficial protective impact on H2O2-injured cells, which pretreatment with YL-11 EPS can substantially decrease ROS levels and enhance SOD enzyme activity. Additionally, the YL-11 EPS exhibited good thickening properties and thermal stability. The EPS's structural information and physicochemical properties provide a basis for studying their structure-function relationships.

Red Grape By-Products from the Demarcated Douro Region: Chemical Analysis, Antioxidant Potential and Antimicrobial Activity against Food-Borne Pathogens.

Wine production is one of the most important agricultural activities. The winemaking process generates a considerable volume of different residues characterized as by-products, such as pomace, seeds, stems, and skins. By-products are rich in polyphenols with antioxidant and antibacterial properties and may act as bacteriostatic or bactericidal agents against food-borne pathogens, improving food safety by enhancing antibiotic efficacy and reducing bacterial resistance. The aim of this study was to evaluate the phenolic composition and antioxidant activity of grape components (skins, seeds, and stems) from three red grape varieties (Periquita, Gamay, and Donzelinho Tinto) and determine their antibacterial activity against antibiotic-resistant bacteria, including Escherichia coli in food-producing animals and Listeria monocytogenes from food products and food-related environments. Ten phenolic compounds were quantified in these red grape varieties, with specific compounds found in different parts of the grape, including phenolic acids and flavonoids. Flavonoids are abundant in seeds and stems, malvidin-3-O-glucoside being the main anthocyanin in skins. The ethanolic extract from the seeds showed in vitro concentration-dependent activity against reactive species like •NO and O2•-. Gamay extract was the most effective, followed by Donzelinho Tinto and Periquita. Extracts showed varying antibacterial activity against Gram-positive and Gram-negative bacteria, with stronger effects on Gram-positive bacteria. L. monocytogenes was more susceptible, while E. coli was limited to three strains. Seeds exhibited the strongest antibacterial activity, followed by stems. The results of our study provide evidence of the potential of grape by-products, particularly seeds, as sources of bioactive compounds with antioxidant and antibacterial properties, offering promising avenues for enhancing food safety and combating antibiotic resistance in food production and related environments.