Inhibition of NADPH oxidase alleviates germ cell apoptosis and ER stress during testicular ischemia reperfusion injury

Testicular torsion and detorsion (TTD) is a serious urological condition affecting young males that is underlined by an ischemia reperfusion injury (tIRI) to the testis as the pathophysiological mechanism. During tIRI, uncontrolled production of oxygen reactive species (ROS) causes DNA damage leading to germ cell apoptosis (GCA). The aim of the study is to explore whether inhibition of NADPH oxidase (NOX), a major source of intracellular ROS, will prevent tIRI-induced GCA and its association with endoplasmic reticulum (ER) stress. Sprague-Dawley rats (n = 36) were divided into three groups: sham, tIRI only and tIRI treated with apocynin (a NOX inhibitor). Rats undergoing tIRI endured an ischemic injury for 1 h followed by 4 h of reperfusion. Spermatogenic damage was evaluated histologically, while cellular damages were assessed using real time PCR, immunofluorescence staining, Western blot and biochemical assays. Disrupted spermatogenesis was associated with increased lipid and protein peroxidation and decreased antioxidant activity of the enzyme superoxide dismutase (SOD) as a result of tIRI. In addition, increased DNA double strand breaks and formation of 8-OHdG adducts associated with increased phosphorylation of the DNA damage response (DDR) protein H2AX. The ASK1/JNK apoptosis signaling pathway was also activated in response to tIRI. Finally, increased immuno-expression of the unfolded protein response (UPR) downstream targets: GRP78, eIF2-α1, CHOP and caspase 12 supported the presence of ER stress. Inhibition of NOX by apocynin protected against tIRI-induced GCA and ER stress. In conclusion, NOX inhibition minimized tIRI-induced intracellular oxidative damages leading to GCA and ER stress.     

Potential mechanisms underlying the promoting effects of 3D collagen scaffold culture on stemness and drug resistance of glioma cells

Background3D collagen scaffold culture is a good tool to study glioma metastasis and recurrence in vitro.MethodsThe effect of 3D collagen culture on the colony formation, the sphere formation, and drug sensitivity of glioma cells was observed by soft-agar colony formation assays, sphere formation assays, and CCK-8 assays, respectively. 3D-glioma-drug genes were identified by previous results and online databases. Gene enrichment and PPI analyses were performed by R software and Metacsape. Hub 3D-glioma-drug genes were screened by STRING and Cytoscape. TCGA and CGGA databases and R software were used to analyze the distribution of hub genes in glioma and their effects on the prognosis. Western Blot was used to verify the effect of 3D collagen culture on the expression of hub genes. miRNAs targeting hub genes were predicted by ENCORI.Results3D collagen scaffold culture promoted colony formation, sphere formation, and drug resistance of glioma cells. There were 77 3D-glioma-drug genes screened, and the pathways enriched in the protein interaction network mainly included responses to stressors, DNA damage and repair, and drug metabolism. Hub 3D-glioma-drug genes were AKT1, ATM, CASP3, CCND1, EGFR, PARP1, and TP53. These genes and predicted miRNAs were expressed differentially in glioma samples and partially affected the prognosis of patients with glioma. These findings suggested these hub genes and miRNAs may play a key role in the effects generated by the 3D culture model and become new markers for glioma diagnosis and treatment.     

Molecular dynamics and simulation analysis against superoxide dismutase (SOD) target of Micrococcus luteus with secondary metabolites from Bacillus licheniformis recognized by genome mining approach

Micrococcus luteus, also known as M. luteus, is a bacterium that inhabits mucous membranes, human skin, and various environmental sources. It is commonly linked to infections, especially among individuals who have compromised immune systems. M. luteus is capable of synthesizing the enzyme superoxide dismutase (SOD) as a component of its protective response to reactive oxygen species (ROS). This enzyme serves as a promising target for drug development in various diseases. The current study utilized a subtractive genomics approach to identify potential therapeutic targets from M. luteus. Additionally, genome mining was employed to identify and characterize the biosynthetic gene clusters (BGCs) responsible for the production of secondary metabolites in Bacillus licheniformis (B. licheniformis), a bacterium known for its production of therapeutically relevant secondary metabolites. Subtractive genomics resulted in identification of important extracellular protein SOD as a drug target that plays a crucial role in shielding cells from damage caused by ROS. Genome mining resulted in identification of five potential ligands (secondary metabolites) from B. licheniformis such as, Bacillibactin (BAC), Paenibactin (PAE), Fengycin (FEN), Surfactin (SUR) and Lichenysin (LIC). Molecular docking was used to predict and analyze the binding interactions between these five ligands and target protein SOD. The resulting protein–ligand complexes were further analyzed for their motions and interactions of atoms and molecules over 250 ns using molecular dynamics (MD) simulation analysis. The analysis of MD simulations suggests, Bacillibactin as the probable candidate to arrest the activities of SOD. All the five compounds reported in this study were found to act by directly/indirectly interacting with ROS molecules, such as superoxide radicals (O₂–) and hydrogen peroxide (H₂O₂), and transforming them into less reactive species. This antioxidant activity contributes to its protective effects against oxidative stress-induced damage in cells making them likely candidate for various applications, including in the development of antioxidant-based therapies, nutraceuticals, and functional foods.     

Comparative study of the antioxidant activity of the essential oils of five plants against the H2O2 induced stress in Saccharomyces cerevisiae

The purpose of this work was to investigate the protective effect of five essential oils (EOs); Rosmarinus officinalis, Thymus vulgaris, Origanum compactum Benth., Eucalyptus globulus Labill. and Ocimum basilicum L.; against oxidative stress induced by hydrogen peroxide in Saccharomyces cerevisiae. The chemical composition of the EOs was analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS). The in vitro antioxidant activity was evaluated and the protective effect of EOs was investigated. Yeast cells were pretreated with different concentrations of EOs (6.25–25 µg/ml) for an hour then incubated with H₂O₂ (2 mM) for an additional hour. Cell viability, antioxidants (Catalase, Superoxide dismutase and Glutathione reductase) and metabolic (Succinate dehydrogenase) enzymes, as well as the level of lipid peroxidation (LPO) and protein carbonyl content (PCO) were evaluated. The chemical composition of EOs has shown the difference qualitatively and quantitatively. Indeed, O. compactum mainly contained Carvacrol, O. basilicum was mainly composed of Linalool, T. vulgaris was rich in thymol, R. officinalis had high α-Pinene amount and for E. globulus, eucalyptol was the major compound. The EOs of basil, oregano and thyme were found to possess the highest amount of total phenolic compounds. Moreover, they have shown the best protective effect on yeast cells against oxidative stress induced by H₂O₂. In addition, in a dose dependent manner of EOs in yeast medium, treated cells had lower levels of LPO, lower antioxidant and metabolic enzymes activity than cells exposed to H₂O₂ only. The cell viability was also improved. It seems that the studied EOs are efficient natural antioxidants, which can be exploited to protect against damages and serious diseases related to oxidative stress.     

A scaffold replacement approach towards new sirtuin 2 inhibitors

Sirtuins (SIRT1–SIRT7) are an evolutionary conserved family of NAD⁺-dependent protein deacylases regulating the acylation state of ε-N-lysine residues of proteins thereby controlling key biological processes. Numerous studies have found association of the aberrant enzymatic activity of SIRTs with various diseases like diabetes, cancer and neurodegenerative disorders. Previously, we have shown that substituted 2-alkyl-chroman-4-one/chromone derivatives can serve as selective inhibitors of SIRT2 possessing an antiproliferative effect in two human cancer cell lines. In this study, we have explored the bioisosteric replacement of the chroman-4-one/chromone core structure with different less lipophilic bicyclic scaffolds to overcome problems associated to poor physiochemical properties due to a highly lipophilic substitution pattern required for achieve a good inhibitory effect. Various new derivatives based on the quinolin-4(1H)-one scaffold, bicyclic secondary sulfonamides or saccharins were synthesized and evaluated for their SIRT inhibitory effect. Among the evaluated scaffolds, the benzothiadiazine-1,1-dioxide-based compounds showed the highest SIRT2 inhibitory activity. Molecular modeling studies gave insight into the binding mode of the new scaffold-replacement analogues.     

Thiol antioxidants protect human lens epithelial (HLE B-3) cells against tert-butyl hydroperoxide-induced oxidative damage and cytotoxicity

Oxidative damage to lens epithelial cells plays an important role in the development of age-related cataract, and the health of the lens has important implications for overall ocular health. As a result, there is a need for effective therapeutic agents that prevent oxidative damage to the lens. Thiol antioxidants such as tiopronin or N-(2-mercaptopropionyl)glycine (MPG), N-acetylcysteine amide (NACA), N-acetylcysteine (NAC), and exogenous glutathione (GSH) may be promising candidates for this purpose, but their ability to protect lens epithelial cells is not well understood. The effectiveness of these compounds was compared by exposing human lens epithelial cells (HLE B-3) to the chemical oxidant tert-butyl hydroperoxide (tBHP) and treating the cells with each of the antioxidant compounds. MTT cell viability, apoptosis, reactive oxygen species (ROS), and levels of intracellular GSH, the most important antioxidant in the lens, were measured after treatment. All four compounds provided some degree of protection against tBHP-induced oxidative stress and cytotoxicity. Cells treated with NACA exhibited the highest viability after exposure to tBHP, as well as decreased ROS and increased intracellular GSH. Exogenous GSH also preserved viability and increased intracellular GSH levels. MPG scavenged significant amounts of ROS, and NAC increased intracellular GSH levels. Our results suggest that both scavenging ROS and increasing GSH may be necessary for effective protection of lens epithelial cells. Further, the compounds tested may be useful for the development of therapeutic strategies that aim to prevent oxidative damage to the lens.     

Rational design,synthesis and biological evaluation of novel multitargeting anti-AD iron chelators with potent MAO-B inhibitory and antioxidant activity

A series of (3-hydroxypyridin-4-one)-coumarin hybrids were developed and investigated as potential multitargeting candidates for the treatment of Alzheimer's disease (AD) through the incorporation of iron-chelating and monoamine oxidase B (MAO-B) inhibition. This combination endowed the hybrids with good capacity to inhibit MAO-B as well as excellent iron-chelating effects. The pFe³⁺ values of the compounds were ranging from 16.91 to 20.16, comparable to more potent than the reference drug deferiprone (DFP). Among them, compound 18d exhibited the most promising activity against MAO-B, with an IC₅₀ value of 87.9 nM. Moreover, compound 18d exerted favorable antioxidant activity, significantly reversed the amyloid-β_1-42 (Aβ_1-42) induced PC12 cell damage. More importantly, 18d remarkably ameliorated the cognitive dysfunction in a scopolamine-induced mice AD model. In brief, a series of hybrids with potential anti-AD effect were successfully obtained, indicating that the design of iron chelators with MAO-B inhibitory and antioxidant activities is an attractive strategy against AD progression.     

A Chitosan-PLGA based catechin hydrate nanoparticles used in targeting of lungs and cancer treatment

ObjectiveTo prepare a novel Chitosan (CS)-coated-PLGA-NPs of catechin hydrate (CTH) and to improve lungs bioavailability via direct nose to lungs-delivery for the comparative assessment of a pulmokinetics study by the first-time UHPLC-MS/MS developed method in the treatment of lungs cancer via anticancer activities on H1299 lung cancer cells.Material and methodsPLGA-NPs was prepared by solvent evaporation (double emulsion) method followed by coated with chitosan (CS) and evaluated based on release and permeation of drug, a comparative pulmokinetics study with their anticancer activities on H1299 lung cancer cells.ResultsThe particle size, PDI and ZP of the optimized CAT-PLGA-NPs and CS-CAT-PLGA-NPs were determined 124.64 ± 12.09 nm and 150.81 ± 15.91 nm, 0.163 ± 0.03 and 0.306 ± 0.03, –3.94 ± 0.19 mV and 26.01 ± 1.19 mV respectively. Furthermore, higher entrapment efficiency was observed for CS-CAT PLGA NPs. The release pattern of the CS-CAT-PLGA NPs was found to favor the release of entrapped CAT within the cancer microenvironment. CS-CAT-PLGA-NPs exposed on H1299 cancer cells upto 24.0 h was found to be higher cytotoxic as compared to CAT-solution (CAT-S). CS-CAT-PLGA-NPs showed higher apoptosis of cancer cells after their exposure as compared to CAT-S. CS-CTH-PLGA-NPs showed tremendous mucoadhesive-nature as compared to CTH-S and CS-CTH-PLGA NPs by retention time (RT) of 0.589 min, and m/z of 289.21/109.21 for CTH alongwith RT of 0.613 min and m/z of 301.21/151.21 was found out for IS (internal standard), i.e. Quercetin). Likewise, for 1–1000 ng mL⁻¹ (linear range) of % accuracy (92.01–99.31%) and %CV (inter & intra-day, i.e. 2.14–3.33%) was determined. The improved C_max with AUC_0–24 was observed extremely significant (p < 0.001) via i.n. as compared oral and i.v. in the wistar rat’s lungs. The CS-approach was successfully designed and safely delivered CAT to the lungs without causing any risk.ConclusionCS-CTH-PLGA-NPs were showed a significant role (p < 0.001) for the enhancement of lungs-bioavailability and potentially promising approach to treat lung cancers. CS-CTH-PLGA-NPs did not cause any toxicity, it showed safety and have no obvious toxic-effects on the rat’s lungs and does not produce any mortality followed by no abnormal findings in the treated-rats.     

Inhibition of Mycobacterium tuberculosis InhA: Design,synthesis and evaluation of new di-triclosan derivatives

Multi-drug resistant tuberculosis (MDR-TB) represents a growing problem for global healthcare systems. In addition to 1.3 million deaths in 2018, the World Health Organisation reported 484,000 new cases of MDR-TB. Isoniazid is a key anti-TB drug that inhibits InhA, a crucial enzyme in the cell wall biosynthesis pathway and identical in Mycobacterium tuberculosis and M. bovis. Isoniazid is a pro-drug which requires activation by the enzyme KatG, mutations in KatG prevent activation and confer INH-resistance. ‘Direct inhibitors’ of InhA are attractive as they would circumvent the main clinically observed resistance mechanisms. A library of new 1,5-triazoles, designed to mimic the structures of both triclosan molecules uniquely bound to InhA have been synthesised. The inhibitory activity of these compounds was evaluated using isolated enzyme assays with 2 (5-chloro-2-(4-(5-(((4-(4-chloro-2-hydroxyphenoxy)benzyl)oxy)methyl)-1H-1,2,3-triazol-1-yl)phenoxy)phenol) exhibiting an IC₅₀ of 5.6 µM. Whole-cell evaluation was also performed, with 11 (5-chloro-2-(4-(5-(((4-(cyclopropylmethoxy)benzyl)oxy)methyl)-1H-1,2,3-triazol-1-yl)phenoxy)phenol) showing the greatest potency, with an MIC₉₉ of 12.9 µM against M. bovis.     

Isolation of diverse bioactive compounds from Euphorbia balsamifera: Cytotoxicity and antibacterial activity studies

Antibacterial and cytotoxic activities of Euphorbia balsamifera, fractions and pure compounds were evaluated. The cytotoxic assays for HCT116, HePG2 and MCF7 showed a significant IC₅₀: 54.7 and 76.2 µg/mL of non-polar fraction “n-hexane” against HCT116 and HePG2, respectively. Antibacterial results revealed that plant fractions exhibited significant potential against the tested pathogens than the total extract where n-butanol and ethyl acetate fractions showed significant antibacterial activity (P < 0.05) against tested bacterial strains. Isolation and structure determination of compounds from n-hexane and n-butanol fractions were performed. From n-hexane fraction, 29-nor-cycloartanol (1), lanost-8-en-3-ol (2a), cycloartanol (2b) and kampferol-3,4'-dimethyl ether (3) were isolated and structurally identified, along with 24 compounds were tentatively identified by GC–MS. From the polar n-butanol fraction, 4-O-β-D-glucopyranosyl-2-hydroxy-6-methoxyacetophenone (4), 4-O-α-L-rhamnosyl-(1 → 6)-β-D-glucopyranosyl-2-hydroxy-6methoxy-acetophenone (5), quercetin-3-O-glucopyranoside (6) and isoorientin (7) were assigned. Structures of the obtained compounds were determined by nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry. Except compounds 1 and 5, all reported compounds announced antibacterial efficiency. Compound 2 showed selectively the highest activity against Enterococcus faecalis (22 ± 0.13 mm), meanwhile 4-O-β-D-glucopyranosyl-2-hydroxy-6-methoxyacetophenone (4) showed broadly the highest antibacterial activity with MIC of 1.15–1.88 mg/mL against the test Gram-positive and Gram-negative bacteria. Cytotoxic assays indicated that kampferol-3,4'-dimethyl ether (3) exhibited the highest activity with matching IC₅₀ values to doxorubicin; 111.46, 42.67 and 44.90 µM against HCT116, HePG2 and MCF7, respectively, however, it is toxic on retina normal cell line RPE1.     

A novel Golgi mannosidase inhibitor: Molecular design,synthesis, enzyme inhibition,and inhibition of spheroid formation

Effective chemotherapy for solid cancers is challenging due to a limitation in permeation that prevents anticancer drugs from reaching the center of the tumor, therefore unable to limit cancer cell growth. To circumvent this issue, we planned to apply the drugs directly at the center by first collapsing the outer structure. For this, we focused on cell–cell communication (CCC) between N-glycans and proteins at the tumor cell surface. Mature N-glycans establish CCC; however, CCC is hindered when numerous immature N-glycans are present at the cell surface. Inhibition of Golgi mannosidases (GMs) results in the transport of immature N-glycans to the cell surface. This can be employed to disrupt CCC. Here, we describe the molecular design and synthesis of an improved GM inhibitor with a non-sugar mimic scaffold that was screened from a compound library. The synthesized compounds were tested for enzyme inhibition ability and inhibition of spheroid formation using cell-based methods. Most of the compounds designed and synthesized exhibited GM inhibition at the cellular level. Of those, AR524 had higher inhibitory activity than a known GM inhibitor, kifunensine. Moreover, AR524 inhibited spheroid formation of human malignant cells at low concentration (10 µM), based on the disruption of CCC by GM inhibition.     

CRISPR-dependent Base Editing Screens Identify Separation of Function Mutants of RADX with Altered RAD51 Regulatory Activity

RAD51 forms nucleoprotein filaments to promote homologous recombination, replication fork reversal, and fork protection. Numerous factors regulate the stability of these filaments and improper regulation leads to genomic instability and ultimately disease including cancer. RADX is a single stranded DNA binding protein that modulates RAD51 filament stability. Here, we utilize a CRISPR-dependent base editing screen to tile mutations across RADX to delineate motifs required for RADX function. We identified separation of function mutants of RADX that bind DNA and RAD51 but have a reduced ability to stimulate its ATP hydrolysis activity. Cells expressing these RADX mutants accumulate RAD51 on chromatin, exhibit replication defects, have reduced growth, accumulate DNA damage, and are hypersensitive to DNA damage and replication stress. These results indicate that RADX must promote RAD51 ATP turnover to regulate RAD51 and genome stability during DNA replication.     

Identification of SARS-CoV-2 RNA-dependent RNA polymerase inhibitors from the major phytochemicals of Nigella sativa: An in silico approach

The coronavirus disease 2019 (COVID-19), which emerged in December 2019, continues to be a serious health concern worldwide. There is an urgent need to develop effective drugs and vaccines to control the spread of this disease. In the current study, the main phytochemical compounds of Nigella sativa were screened for their binding affinity for the active site of the RNA-dependent RNA polymerase (RdRp) enzyme of the severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). The binding affinity was investigated using molecular docking methods, and the interaction of phytochemicals with the RdRp active site was analyzed and visualized using suitable software. Out of the nine phytochemicals of N. sativa screened in this study, a significant docking score was observed for four compounds, namely α-hederin, dithymoquinone, nigellicine, and nigellidine. Based on the findings of our study, we report that α-hederin, which was found to possess the lowest binding energy (–8.6 kcal/mol) and hence the best binding affinity, is the best inhibitor of RdRp of SARS-CoV-2, among all the compounds screened here. Our results prove that the top four potential phytochemical molecules of N. sativa, especially α-hederin, could be considered for ongoing drug development strategies against SARS-CoV-2. However, further in vitro and in vivo testing are required to confirm the findings of this study.     

Structural basis for proteolytic processing of Aspergillus sojae α-glucosidase L with strong transglucosylation activity

An α-glucosidase from Aspergillus sojae, AsojAgdL, exhibits strong transglucosylation activity to produce α-1,6-glucosidic linkages. The most remarkable structural feature of AsojAgdL is that residues 457–560 of AsojAgdL (designated the NC sequence) is not conserved in other glycoside hydrolase family 31 enzymes, and part of this NC sequence is proteolytically cleaved during its maturation. In this study, the enzyme was expressed in Pichia pastoris, and electrophoretic analysis indicated that the recombinant enzyme, rAsojAgdL, consisted of two polypeptide chains, as observed in the case of the enzyme produced in an Aspergillus strain. The crystal structure of rAsojAgdL was determined in complex with the substrate analog trehalose. Electron density corresponding to residues 496–515 of the NC sequence was not seen, and there were no α-helices or β-strands except for a short α-helix in the structures of residues 457–495 and residues 516–560, both of which belong to the NC sequence. The residues 457–495 and the residues 516–560 both formed extra components of the catalytic domain. The residues 457–495 constituted the entrance of the catalytic pocket of rAsojAgdL, and Gly467, Asp468, Pro469, and Pro470 in the NC sequence were located within 4 Å of Trp400, a key residue involved in binding of the substrate. The results suggest that the proteolytic processing of the NC sequence is related to the formation of the catalytic pocket of AsojAgdL.     

Microtubule-targeting anticancer drug eribulin induces drug efflux transporter P-glycoprotein

This study examined the effects of microtubule-targeting anticancer drugs (paclitaxel, cabazitaxel, and eribulin) on the expression of drug efflux transporter P-glycoprotein, which is encoded by MDR1. Paclitaxel and eribulin induced MDR1 promoter activity in a concentration-dependent manner, while cabazitaxel had little effect in human intestinal epithelial LS174T cells. Overexpression of the nuclear receptor pregnane X receptor (PXR) gene (NR1I2) enhanced paclitaxel- and eribulin-induced MDR1 activation, but expression of the nuclear receptor co-repressor silencing mediator for retinoid and thyroid receptors (SMRT) gene (NCOR2) repressed MDR1 activation. Eribulin increased the mRNA and protein expression of P-glycoprotein in LS174T cells. Cellular uptake of rhodamine 123 and calcein-acetoxymethyl ester (calcein-AM), P-glycoprotein substrates, decreased in paclitaxel- or eribulin-treated LS174T cells. Eribulin also increased MDR1 promoter activity in human breast cancer MCF7 cells. The results suggest that the microtubule-targeting anticancer drug eribulin can induce the drug efflux transporter P-glycoprotein via PXR in human intestinal and breast cancer cells and thus influence the efficacy of anticancer drugs.     

Metabolism of syringyl lignin-derived compounds in Pseudomonas putida enables convergent production of 2-pyrone-4,6-dicarboxylic acid

Valorization of lignin, an abundant component of plant cell walls, is critical to enabling the lignocellulosic bioeconomy. Biological funneling using microbial biocatalysts has emerged as an attractive approach to convert complex mixtures of lignin depolymerization products to value-added compounds. Ideally, biocatalysts would convert aromatic compounds derived from the three canonical types of lignin: syringyl (S), guaiacyl (G), and p-hydroxyphenyl (H). Pseudomonas putida KT2440 (hereafter KT2440) has been developed as a biocatalyst owing in part to its native catabolic capabilities but is not known to catabolize S-type lignin-derived compounds. Here, we demonstrate that syringate, a common S-type lignin-derived compound, is utilized by KT2440 only in the presence of another energy source or when vanAB was overexpressed, as syringate was found to be O-demethylated to gallate by VanAB, a two-component monooxygenase, and further catabolized via extradiol cleavage. Unexpectedly, the specificity (k_cat/K_M) of VanAB for syringate was within 25% that for vanillate and O-demethylation of both substrates was well-coupled to O₂ consumption. However, the native KT2440 gallate-cleaving dioxygenase, GalA, was potently inactivated by 3-O-methylgallate. To engineer a biocatalyst to simultaneously convert S-, G-, and H-type monomers, we therefore employed VanAB from Pseudomonas sp. HR199, which has lower activity for 3MGA, and LigAB, an extradiol dioxygenase able to cleave protocatechuate and 3-O-methylgallate. This strain converted 93% of a mixture of lignin monomers to 2-pyrone-4,6-dicarboxylate, a promising bio-based chemical. Overall, this study elucidates a native pathway in KT2440 for catabolizing S-type lignin-derived compounds and demonstrates the potential of this robust chassis for lignin valorization.     

Turbinaria ornata and its associated epiphytic Bacillus sp. A promising molecule supplier to discover new natural product approaches

Marine ecosystems are highly dependent on macroalgea in providing food and shelter for aquatic organisms, interacting with many bacteria and mostly producing secondary metabolites of potent therapeutic antibacterial property. Screening of marine microbial secondary metabolites of valuable biotechnological and therapeutical applications are now extensively studied. In this study, Bacillus spp. identified by DNA sequencing and found associated with Turbinaria ornata, was screened and characterized for its cell free supernatant (CFS) possible antimicrobial and antibiofilm applications. Among the 7 microbial isolates tested, CFS greatly affected Bacillus subitilis (12 mm) and inhibited equally the yeast isolates Candida albicans, Candida tropicalis and Candida glabrata (10 mm) and had no or negligible effect on S.aureus, E.coli, P. aeruginosa. As for the CFS antibiofilm activity, no difference was revealed from the positive control. Algal crude extracts (methanol, acetone and aqueous), on the other hand, were similarly tested for their antimicrobial activity against the seven microbial isolates, where highest activity was observed with the aqueous crude extract against Staphylococcus aureus(10 mm) and Pseudomonas aeruginosa (9 mm) compared to the negligible effects of methanol and acetone crude extracts. Chemical analysis was performed to reveal the major constituents of both crude algal extracts and Bacillus spp. CFS. FTIR spectrum of the bacterial CFS indicated the presence of bacteriocin as the major lipopeptide responsible for its biological activity. Whereas, methanol and water crude algal extract GC–MS spectra revealed different chemical groups of various combined therapeutical activity mainly Naphthalene, amino ethane-sulfonic acid, pyrlene, Biotin and mercury chloromethyl correspondingly. Thus, the present study, demonstrated the moderate activity of both crude algal extract and the bacterial CFS, however, further investigations are needed for a better biological activity.     

Streptomyces poriferorum sp. nov., a novel marine sponge-derived Actinobacteria species expressing anti-MRSA activity

Marine sponges represent a rich source of uncharacterized microbial diversity, and many are host to microorganisms that produce biologically active specialized metabolites. Here, a polyphasic approach was used to characterize two Actinobacteria strains, P01-B04^T and P01-F02, that were isolated from the marine sponges Geodia barretti (Bowerbank, 1858) and Antho dichotoma (Esper, 1794), respectively. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strains P01-B04^T and P01-F02 are closely related to Streptomyces beijiangensis DSM 41794^T, Streptomyces laculatispora NRRL B-24909^T, and Streptomyces brevispora NRRL B-24910^T. The two strains showed nearly identical 16S rRNA gene sequences (99.93%), and the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) relatedness values were 99.96% and 99.6%, respectively, suggesting that these strains are affiliated with the same species. Chemotaxonomic and culture characteristics of both strains were also consistent with the genus Streptomyces, while phenotypic properties, genome-based comparisons, and phylogenomic analyses distinguished strains P01-B04^T and P01-F02 from their closest phylogenetic relatives. In silico analysis predicted that the 8.9 Mb genome of P01-B04^T contains at least 41 biosynthetic gene clusters (BGCs) encoding secondary metabolites, indicating that this strain could express diverse bioactive metabolites; in support of this prediction, this strain expressed antibacterial activity against Gram-positive bacteria including a clinical isolate of methicillin-resistant Staphylococcus aureus (MRSA) EAMC30. Based on these results, the marine sponge-associated isolates represent a novel species of the genus Streptomyces, for which the name Streptomyces poriferorum sp. nov. is proposed, with P01-B04^T (=DSM 111306^T = CCM 9048^T) as the type strain.