Spectral analysis and Antibacterial activity of the bioactive principles of Sargassum tenerrimum J. Agardh collected from the Red sea, Jazan, Kingdom of Saudi Arabia

Seaweeds are a major marine resource that can be explored to develop novel pharmaceutical molecules. The present study showed the presence of unique bioactive components in the petroleum ether extract (PEE) and methanolic extract (ME) of Sargassum tenerrimum. The gas chromatography-mass spectrometry analysis suggested that the PEE of S. tenerrimum contained antibacterial biomolecules: hexadecanoic acid, methyl ester, 17-pentatriacontene, dasycarpidan-1-methanol, and acetate (ester). However, the ME of S. tenerrimum exhibited better antibacterial effect than the PEE due to the presence of the bioactive compounds 1,2-benzenedicarboxylic acid, diisooctyl ester, tetratetracontane, 1-docosene, 1,2-benzenediol, and benzoic acid. Thus, promising antibacterial molecules can be isolated from S. tenerrimum for better therapeutic use.

Phytochemical screening of Cordia glabrata (MART.) A.DC. extracts and its potential antioxidant, photoprotective, antimicrobial and antiviral activities

Species of the genus Cordia have shown biological activities, such as anti-inflammatory, analgesic, antioxidant, antiviral, and antifungal activities. The species Cordia glabrata (MART) A.DC. Has no information concerning its phytochemical profile and possible biological activities. Thus, this study aimed to evaluate this profile in ethanolic extracts of young, adult and senescent leaves, as well as their antioxidant, photoprotective, antimicrobial, and virucidal potentials. Phytochemical analysis was performed by TLC (thin-layer chromatography) and showed the presence of flavonoids, tannins, and terpenes. The evaluation by UPLC-MS/MS (Ultra performance liquid chromatography - tandem mass spectrometer) evidenced the presence of caffeic (3.89 mgL-1), p-cumaric (6.13 mgL-1), and ferulic (0.58 mgL-1) acids, whilst, in GC/MS (Gas chromatography–mass spectrometry) analysis there was a greater amount of palmitic (51.17%), stearic (20.34%), linoleic (9.62%), and miristic (8.16%) fatty acids. The DPPH (2,2-Diphenyl-1-picrylhydrazyl) and ABTS+ (2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) radicals were used to verify the potential antioxidant activity, observing a better activity for the leaf extract in the adult phenological stage: 54.63 ± 1.06 µgmL-1 (DPPH) and 44.21 ± 1.69 mM (ABTS). The potential photoprotective activity of the extracts was determined by spectrophotometry and the in vitro values of SPF (Sun Protection Factor) in young and adult leaves (5.47 and 5.41, respectively) showed values close to the minimum SPF of 6.0 required by ANVISA (Brazilian Health Regulatory Agency). It was not observed an antimicrobial activity for Staphylococcus aureus with a minimum inhibitory concentration of 2000 μgmL-1, however the anti-herpetic assay against the Herpes simplex virus type 2 (HSV-2) showed a potent virucidal activity at the tested concentrations with CV50 value <0.195 μgmL-1 and a Selectivity Index (SI = CC50 / CV50) greater than 448. The results obtained in this study suggest that extracts of leaves of C. glabrata in their adult phenological stage have potential antioxidant, photoprotective and virucidal activity, considering in vitro test results.

In Vitro Assessment of Organic and Residual Fractions of Nematicidal Culture Filtrates from Thirteen Tropical Trichoderma Strains and Metabolic Profiles of Most-Active

The nematicidal properties of Trichoderma species have potential for developing safer biocontrol agents. In the present study, 13 native Trichoderma strains from T. citrinoviride, T. ghanense (2 strains), T. harzianum (4), T. koningiopsis, T. simmonsii, and T. virens (4) with nematicidal activity were selected and cultured in potato dextrose broth to obtain a culture filtrate (CF) for each. Each CF was partitioned with ethyl acetate to obtain organic (EA) and residual filtrate (RF) fractions, which were then tested on second-stage juveniles (J2s) of the nematodes Meloidogyne javanica and M. incognita in a microdilution assay. The most lethal strains were T. harzianum Th43-14, T. koningiopsis Th41-11, T. ghanense Th02-04, and T. virens Th32-09, which caused 51–100% mortality (%M) of J2s of both nematodes, mainly due to their RF fractions. Liquid chromatography–diode array detector-electrospray-high resolution mass spectrometry analysis of the most-active fractions revealed sesquiterpene and polyketide-like metabolites produced by the four active strains. These native Trichoderma strains have a high potential to develop safer natural products for the biocontrol of Meloidogyne species.

The C-terminal domain of SEC-10 is fundamental for exocyst function, Spitzenkorper organization and cell morphogenesis in Neurospora crassa.

The exocyst is a conserved multimeric complex that participates in the final steps of the secretion of vesicles. In the filamentous fungus Neurospora crassa, the exocyst is crucial for polar growth, morphology, and the organization of the Spitzenkorper (Spk), the apical body where secretory vesicles accumulate before being delivered to the plasma membrane. In the highly polarized cells of N. crassa, the exocyst subunits SEC-3, SEC-5, SEC-6, SEC-8, and SEC-15 were previously found localized at the plasma membrane of the apices of the cells, while EXO-70 and EXO-84 occupied the frontal outer layer of the Spk, occupied by vesicles. The localization of SEC-10 had remained so far elusive. In this work, SEC-10 was tagged with the green fluorescent protein (GFP) either at its N- or C-terminus and found localized at the plasma membrane of growing hyphal tips, similar to what was previously observed for some exocyst subunits. While expression of an N-terminally tagged version of SEC-10 at its native locus was fully viable, expression of a C-terminally tagged version at its native locus resulted in severe hyphal growth and polarity defects. Additionally, a sec-10 knockout mutant in a heterokaryotic state (with genetically different nuclei) was viable but showed a strongly aberrant phenotype, confirming that this subunit is essential to maintain hyphal morphogenesis. Transmission electron microscopy analysis revealed the lack of a Spk in the SEC-10-GFP strain, suggesting a critical role of the exocyst in the vesicular organization at the Spk. Mass spectrometry analysis revealed fewer peptides of exocyst subunits interacting with SEC-10-GFP than with GFP-SEC-10, suggesting an essential role of the C-terminus of SEC-10 in exocyst assembly and/or stability. Altogether, our data suggest that an unobstructed C-terminus of SEC-10 is indispensable for the exocyst complex function and that a GFP tag could be blocking important subunit-subunit interactions.

Oral and Topical Anti-Inflammatory Activity of Jatropha integerrima Leaves Extract in Relation to Its Metabolite Profile

Jatropha integerrima Jacq., family: Euphorbiaceae, is used in India and subtropical Africa to treat different skin conditions. In this study we evaluated the anti-inflammatory activity of J. integerrima leaves extract (JILE) using rat paw edema model. The extract was administered orally (200 and 400 mg/kg) or applied topically as creams at 2.5, 5, and 10% strength. Four hours post-treatment, maximum reduction of edema volume by 63.09% was observed after oral administration of JILE (400 mg/kg) as compared to indomethacin with 60.43%. The extract anti-inflammatory effect was accompanied by a decrease in NO, prostaglandin PGE2, TNF-a and PKC levels by 19, 29.35, 16.9, and 47.83%, respectively. Additionally, topical applications of JILE showed dose dependent reduction in paw edema and resulted in normalized levels of PGE2, TNF-a, and PKC when used as 10% cream. Signs of inflammations were reduced or absent from paw tissue of animals receiving JILE either orally or topically. Finally, liquid chromatography/mass spectrometry analysis of JILE resulted in the annotation of 133 metabolites including 24 diterpenoids, 19 flavonoids, 10 phenolic acid conjugates, 8 cyclic peptides, 6 phytosterols, 4 sesquiterpenes, and 4 coumarins. Several of the annotated metabolites have known anti-inflammatory activity including vitexin, isovitexin, fraxitin, scopeltin, stigmasterol, and many diterpenoidal derivatives.

Volatile Organic Compound Composition and Glandular Trichome Characteristics of In Vitro Propagated Clinopodium pulegium (Rochel) Bräuchler: Effect of Carbon Source

Clinopodium pulegium (Rochel) Bräuchler (Lamiaceae) is an endangered species endemic to the Southern Carpathians. It is characterized by the production of high amounts of essential oils, which emit volatile organic compounds (VOCs) that have an essential role in biotic and abiotic stress responses and in plant–plant and plant–insect interactions. The present study was initiated to phytochemically examine the influence of different carbon sources in the nutrition medium on VOC emissions of micropropagated C. pulegium plants, using gas chromatography–mass spectrometry analysis of headspace VOCs. The volatile profiles were subjected to multivariate analysis with respect to the presence, concentration and type of carbon source in the nutrient medium. In addition, the effect of different carbohydrates on the density and size of the leaf glandular trichomes, the main structures involved in the emission of VOCs, was determined. A total of 19 VOCs, primarily belonging to mono- and sesquiterpenes previously described in plants, were tentatively identified. Six VOCs were produced at levels higher than 2% of the total VOC emission, dominated by pulegone, ß-pinene and menthone. Inclusion of the carbohydrates in the culture media affected the production of the main leaf trichome-associated volatile allelochemicals although the qualitative composition of the volatiles changed only slightly. Multivariate analysis showed that the concentration, rather than the carbohydrate type, influenced the VOC profile.

GSNOR regulates ganoderic acid content in Ganoderma lucidum under heat stress through S-nitrosylation of catalase

As a master regulator of the balance between NO signaling and protein S-nitrosylation, S-nitrosoglutathione (GSNO) reductase (GSNOR) is involved in various developmental processes and stress responses. However, the proteins and specific sites that can be S-nitrosylated, especially in microorganisms, and the physiological functions of S-nitrosylated proteins remain unclear. Herein, we show that the ganoderic acid (GA) content in GSNOR-silenced (GSNORi) strains is significantly lower (by 25%) than in wild type (WT) under heat stress (HS). Additionally, silencing GSNOR results in an 80% increase in catalase (CAT) activity, which consequently decreases GA accumulation via inhibition of ROS signaling. The mechanism of GSNOR-mediated control of CAT activity may be via protein S-nitrosylation. In support of this possibility, we show that CAT is S-nitrosylated (as shown via recombinant protein in vitro and via GSNORi strains in vivo). Additionally, Cys (cysteine) 401, Cys642 and Cys653 in CAT are S-nitrosylation sites (assayed via mass spectrometry analysis), and Cys401 may play a pivotal role in CAT activity. These findings indicate a mechanism by which GSNOR responds to stress and regulates secondary metabolite content through protein S-nitrosylation. Our results also define a new S-nitrosylation site and the function of an S-nitrosylated protein regulated by GSNOR in microorganisms.

Functional Identification of MicroRNA-Centered Complexes in C. Elegans.

microRNAs (miRNAs) are crucial for normal development and physiology. To identify factors that might coordinate with miRNAs to regulate gene expression, we used 2’-O methylated oligonucleotides to precipitate Caenorhabditis elegans let-7, miR-58, and miR-2 miRNAs and the associated proteins. A total of 211 proteins were identified through mass-spectrometry analysis of miRNA co-precipitates, which included previously identified interactors of key miRNA pathway components. Gene ontology analysis of the identified interactors revealed an enrichment for RNA binding proteins, suggesting that we captured proteins that may be involved in mRNA lifecycle. To determine which miRNA interactors are important for miRNA activity, we used RNAi to deplete putative miRNA co-factors in animals with compromised miRNA activity and looked for alterations of the miRNA mutant phenotypes. Depletion of 25 of 39 tested genes modified the miRNA mutant phenotypes in three sensitized backgrounds. Modulators of miRNA phenotypes ranged from RNA binding proteins RBD-1 and CEY-1 to metabolic factors such as DLST-1 and ECH-5, among others. The observed functional interactions suggest widespread coordination of these proteins with miRNAs to ultimately regulate gene expression. This study provides a foundation for future investigations aimed at deciphering the molecular mechanisms of miRNA-mediated gene regulation.

The Effects and Mechanisms of Action of TC-G 1008, GPR39 Agonist, in Animal Models of Seizures and Epilepsy

Background and purpose: The G-protein coupled receptor 39 (GPR39) may be activated by zinc ions. Activation of GPR39 was suggested as a novel pharmacological strategy for treating seizures. Experimental approach: We utilized a specific agonist of GPR39, TC-G 1008, and the nonspecific agonist, zinc chloride and a variety of models of acute seizures or a chronic model of epilepsy which were induced in non-genetically modified mice, GPR39 knockout mice or in zebrafish larvae. We examined total serum zinc (by Inductively Coupled Plasma Optical Emission Spectrometry) as well as intracellular zinc ([Zn2+]I) (by Zinpyr-1 staining) concentrations and the expression of selected proteins (by Western blot) which are associated with GPR39 signaling in the hippocampus. Key results: Liquid chromatography tandem mass spectrometry analysis showed that TC-G 1008 is brain penetrant. TC-G 1008 decreased the seizure threshold in the maximal electroshock seizure (MES) threshold test, but it increased the seizure threshold in the 6-Hz induced seizure threshold test. The behavioral effects of TC-G 1008 and MES or 6-Hz seizure were accompanied by alterations in hippocampal [Zn2+]I. TC-G 1008 increased the mean duration of EEG discharges in response to pentylenetetrazole (PTZ) in zebrafish larvae and facilitated the development of PTZ kindling in mice. Using GPR39 knockout mouse line, generated by the CRISPR-Cas-9 method, we showed that GPR39 is a target for TC-G 1008 regarding PTZ-induced epileptogenesis. Conclusion and implications: Our in vivo data obtained using TC-G 1008 generally argue against GPR39 activation as a therapeutic strategy for alleviating seizures/epilepsy.

Myxopyronin B inhibits growth of a Fidaxomicin-resistant Clostridioides difficile isolate and interferes with toxin synthesis

The anaerobic, gastrointestinal pathogen Clostridioides difficile can cause severe forms of enterocolitis which is mainly mediated by the toxins it produces. The RNA polymerase inhibitor Fidaxomicin is the current gold standard for the therapy of C. difficile infections due to several beneficial features including its ability to suppress toxin synthesis in C. difficile. In contrast to the Rifamycins, Fidaxomicin binds to the RNA polymerase switch region, which is also the binding site for Myxopyronin B. Here, serial broth dilution assays were performed to test the susceptibility of C. difficile and other anaerobes to Myxopyronin B, proving that the natural product is considerably active against C. difficile and that there is no cross-resistance between Fidaxomicin and Myxopyronin B in a Fidaxomicin-resistant C. difficile strain. Moreover, mass spectrometry analysis indicated that Myxopyronin B is able to suppress early phase toxin synthesis in C. difficile to the same degree as Fidaxomicin. Conclusively, Myxopyronin B is proposed as a new lead structure for the design of novel antibiotics for the therapy of C. difficile infections.