scholarly journals Saliniquinone Derivatives, Saliniquinones G−I and Heraclemycin E, from the Marine Animal-Derived Nocardiopsis aegyptia HDN19-252

Marine Drugs ◽  
2021 ◽  
Vol 19 (10) ◽  
pp. 575
Author(s):  
Luning Zhou ◽  
Xuedong Chen ◽  
Chunxiao Sun ◽  
Yimin Chang ◽  
Xiaofei Huang ◽  
...  
Keyword(s):  
Natural Products ◽  
Inhibitory Activity ◽  
Marine Animal ◽  
Bacterial Strains ◽  
Coagulase Negative Staphylococci ◽  
Molecular Networking ◽  
Methicillin Resistant ◽  
Anthraquinone Derivatives ◽  
Antarctic Marine ◽  
The Antarctic

Four new anthraquinone derivatives, namely saliniquinones G−I (1−3) and heraclemycin E (4), were obtained from the Antarctic marine-derived actinomycete Nocardiopsis aegyptia HDN19-252, guided by the Global Natural Products Social (GNPS) molecular networking platform. Their structures, including absolute configurations, were elucidated by extensive NMR, MS, and ECD analyses. Compounds 1 and 2 showed promising inhibitory activity against six tested bacterial strains, including methicillin-resistant coagulase-negative staphylococci (MRCNS), with MIC values ranging from 3.1 to 12.5 μM.

scholarly journals Dilignans with a Chromanol Motif Discovered by Molecular Networking from the Stem Barks of Magnolia obovata and Their Proprotein Convertase Subtilisin/Kexin Type 9 Expression Inhibitory Activity

Biomolecules ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 463
Author(s):  
Jongmin Ahn ◽  
Hee-Sung Chae ◽  
Pisey Pel ◽  
Young-Mi Kim ◽  
Young Hee Choi ◽  
...  
Keyword(s):  
Natural Products ◽  
Lipid Metabolism ◽  
Inhibitory Activity ◽  
Bioinformatic Analysis ◽  
Chemical Diversity ◽  
Molecular Networking ◽  
Time Consumption ◽  
Magnolia Obovata ◽  
Novel Structure ◽  
Small Set

Natural products have been fundamental materials in drug discovery. Traditional strategies for observing natural products with novel structure and/or biological activity are challenging due to large cost and time consumption. Implementation of the MS/MS-based molecular networking strategy with the in silico annotation tool is expected to expedite the dereplication of secondary metabolites. In this study, using this tool, two new dilignans with a 2-phenyl-3-chromanol motif, obovatolins A (1) and B (2), were discovered from the stem barks of Magnolia obovata Thunb. along with six known compounds (3–8), expanding chemical diversity of lignan skeletons in this natural source. Their structures and configurations were elucidated using spectroscopic data. All isolates were evaluated for their PCSK9 mRNA expression inhibitory activity. Obovatolins A (1) and B (2), and magnolol (3) showed potent lipid controlling activities. To identify transcriptionally controlled genes by 1 along with downregulation of PCSK9, using small set of genes (42 genes) related to lipid metabolism selected from the database, focused bioinformatic analysis was carried out. As a result, it showed the correlations between gene expression under presence of 1, which led to detailed insight of the lipid metabolism caused by 1.

Global Natural Products Social Molecular Networking (GNPS): Fundamentals and Applications

2020 ◽  
Author(s):  
A. KARUPPUSAMY ◽  
F. F. FIGUEIREDO ◽  
Domingos Tabajara de Oliveira MARTINS ◽  
N.Z.T. JESUS ◽  
A.M. CARABALLO-RODRÍGUEZ
Keyword(s):  
Natural Products ◽  
Molecular Networking

Lipids and Free Fatty Acids of Red Sea Avrainvillea amadelpha, Holothuria atra, and Sarcocornia fruticosa Inhibit Marine Bacterial Biofilms

2020 ◽  
Vol 17 (6) ◽  
pp. 466-471
Author(s):  
Usama W. Hawas ◽  
Fekri Shaher ◽  
Mohamed Ghandourah ◽  
Lamia T. Abou El-Kassem ◽  
Sathianeson Satheesh ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Red Sea ◽  
Inhibitory Activity ◽  
Sea Cucumber ◽  
Bacterial Biofilms ◽  
Antibiofilm Activity ◽  
Bacterial Strains ◽  
Holothuria Atra ◽  
Sarcocornia Fruticosa

This study aimed at evaluating the antibiofilm activity of the Red Sea metabolites from green alga Avrainvillea amadelpha, sea cucumber Holothuria atra and costal plant Sarcocornia fruticosa against three biofilm bacterial strains isolated from Jeddah coast. Free fatty acids (FFAs) and other lipoidal matters were extracted from these organisms and analyzed by GC-MS. The composition of lipoidal fractions showed that A. amadelpha is rich by 74% saturated FAs, while sea cucumber H. atra revealed high content (60%) of unsaturated FAs. Palmitic acid is the major FA component in all species ranging from 14.5 to 26.7%. Phytol, sterols and hydrocarbons (C8-C29) were represented in the alga A. amadelpha as high contents with values 25.8, 21.9 and 18.5%, respectively. The extracts and lipoidal contents showed biofilm inhibitory activity against the isolated bacterial strains, where the unsaponified lipoidal fraction of S. fruticosa exhibited highest inhibitory activity against Planomicrobium sp. at concentration of 200 µg/mL.

scholarly journals Nasopharyngeal Carriage of Methicillin-Resistant Staphylococcus aureus (MRSA) among Sickle Cell Disease (SCD) Children in the Pneumococcal Conjugate Vaccine Era

2021 ◽  
Vol 13 (1) ◽  
pp. 191-204
Author(s):  
Nicholas T. K. D. Dayie ◽  
Deborah N. K. Sekoh ◽  
Fleischer C. N. Kotey ◽  
Beverly Egyir ◽  
Patience B. Tetteh-Quarcoo ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Sickle Cell Disease ◽  
Conjugate Vaccine ◽  
Sickle Cell ◽  
Pneumococcal Conjugate Vaccine ◽  
Diffusion Method ◽  
Nasopharyngeal Carriage ◽  
Cell Disease ◽  
Coagulase Negative Staphylococci ◽  
Methicillin Resistant

The aim of this cross-sectional study was to investigate Staphylococcus aureus nasopharyngeal carriage epidemiology in relation to other nasopharyngeal bacterial colonizers among sickle cell disease (SCD) children about five years into pneumococcal conjugate vaccine 13 (PCV-13) introduction in Ghana. The study involved bacteriological culture of nasopharyngeal swabs obtained from 202 SCD children recruited from the Princess Marie Louise Children’s Hospital. S. aureus isolates were identified using standard methods and subjected to antimicrobial susceptibility testing using the Kirby-Bauer disc diffusion method. Cefoxitin-resistant S. aureus isolates were screened for carriage of the mecA, pvl, and tsst-1 genes using multiplex polymerase chain reaction. The carriage prevalence of S. aureus was 57.9% (n = 117), and that of methicillin-resistant S. aureus (MRSA) was 3.5% (n = 7). Carriage of the mecA, pvl, and tsst-1 genes were respectively demonstrated in 20.0% (n = 7), 85.7% (n = 30), and 11.4% (n = 4) of the cefoxitin-resistant S. aureus isolates. PCV-13 vaccination (OR = 0.356, p = 0.004) and colonization with coagulase-negative staphylococci (CoNS) (OR = 0.044, p < 0.0001) each protected against S. aureus carriage. However, none of these and other features of the participants emerged as a determinant of MRSA carriage. The following antimicrobial resistance rates were observed in MRSA compared to methicillin-sensitive S. aureus: clindamycin (28.6% vs. 4.3%), erythromycin (42.9% vs. 19.1%), tetracycline (100% vs. 42.6%), teicoplanin (14.3% vs. 2.6%), penicillin (100% vs. 99.1%), amoxiclav (28.6% vs. 3.5%), linezolid (14.3% vs. 0.0%), ciprofloxacin (42.9% vs. 13.9%), and gentamicin (42.9% vs. 13.0%). The proportion of S. aureus isolates that were multidrug resistant was 37.7% (n = 46). It is concluded that S. aureus was the predominant colonizer of the nasopharynx of the SCD children, warranting the continuous monitoring of this risk group for invasive S. aureus infections.

scholarly journals Use of Pulsed-Field Gel Electrophoresis to Determine the Source of Methicillin-Resistant Staphylococcus aureus Bacteremia

2021 ◽  
Vol 13 (3) ◽  
pp. 602-610
Author(s):  
Eugene Y. H. Yeung ◽  
Ivan Gorn
Keyword(s):  
Staphylococcus Aureus ◽  
Gel Electrophoresis ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Epidemiological Studies ◽  
Pelvic Trauma ◽  
Pulsed Field Gel Electrophoresis ◽  
Bacterial Strains ◽  
Methicillin Resistant ◽  
Pulsed Field ◽  
Clinical Cases

Pulsed-field gel electrophoresis (PFGE) has historically been considered the gold standard in fingerprinting bacterial strains in epidemiological studies and outbreak investigations; little is known regarding its use in individual clinical cases. The current study detailed two clinical cases in which PFGE helped to determine the source of their methicillin-resistant Staphylococcus aureus (MRSA) bacteremia. Patient A was found to have MRSA bacteremia after trauma in her pelvic area. MRSA was also found in her groin but not in her nostril and rectum. PFGE was performed that showed variable bands of her MRSA isolates from blood and groin, suggestive of different strains of MRSA. Her MRSA bacteremia was determined to be unrelated to her pelvic trauma. Patient B was found to have MRSA bacteremia after colonoscopy. MRSA was also found in his nostril and rectum. PFGE was performed that showed variable bands of his MRSA isolates from blood and rectum but identical bands of MRSA isolates from his blood and nostril. His MRSA bacteremia was determined to be unrelated to his colonoscopy procedure. The current study demonstrates the use of PFGE to rule out the source of bacteremia in individual clinical cases.

scholarly journals Antimicrobial Metabolites against Methicillin-Resistant Staphylococcus aureus from the Endophytic Fungus Neofusicoccum australe

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1094
Author(s):  
Melissa M. Cadelis ◽  
Soeren Geese ◽  
Benedict B. Uy ◽  
Daniel R. Mulholland ◽  
Shara J. van de Pas ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Natural Products ◽  
Structure Elucidation ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Inhibitory Concentration ◽  
Spectroscopic Methods ◽  
Methicillin Resistant ◽  
Bioassay Guided Fractionation ◽  
Antimicrobial Metabolites

Antimicrobial bioassay-guided fractionation of the endophytic fungi Neofusicoccum australe led to the isolation of a new unsymmetrical naphthoquinone dimer, neofusnaphthoquinone B (1), along with four known natural products (2–5). Structure elucidation was conducted by nuclear magnetic resonance (NMR) spectroscopic methods, and the antimicrobial activity of all the natural products was investigated, revealing 1 to be moderately active towards methicillin-resistant Staphylococcus aureus (MRSA) with a minimum inhibitory concentration (MIC) of 16 µg/mL.

scholarly journals In Vitro activity of a Novel Benzoquinolizine Antibiotic, Levonadifloxacin (WCK 771) against Blood Stream Gram-Positive Isolates from a Tertiary Care Hospital

2020 ◽  
Vol 12 (03) ◽  
pp. 230-232
Author(s):  
Dhruv Mamtora ◽  
Sanjith Saseedharan ◽  
Ritika Rampal ◽  
Prashant Joshi ◽  
Pallavi Bhalekar ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Tertiary Care Hospital ◽  
Tertiary Care ◽  
Blood Stream ◽  
Tolerability Profile ◽  
Care Hospital ◽  
Coagulase Negative Staphylococci ◽  
Gram Positive ◽  
Methicillin Resistant

Abstract Background Blood stream infections (BSIs) due to Gram-positive pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) are associated with high mortality ranging from 10 to 60%. The current anti-MRSA agents have limitations with regards to safety and tolerability profile which limits their prolonged usage. Levonadifloxacin and its oral prodrug alalevonadifloxacin, a novel benzoquinolizine antibiotic, have recently been approved for acute bacterial skin and skin structure infections including diabetic foot infections and concurrent bacteremia in India. Methods The present study assessed the potency of levonadifloxacin, a novel benzoquinolizine antibiotic, against Gram-positive blood stream clinical isolates (n = 31) collected from January to June 2019 at a tertiary care hospital in Mumbai, India. The susceptibility of isolates to antibacterial agents was defined following the Clinical and Laboratory Standard Institute interpretive criteria (M100 E29). Results High prevalence of MRSA (62.5%), quinolone-resistant Staphylococcus aureus (QRSA) (87.5%), and methicillin-resistant coagulase-negative staphylococci (MR-CoNS) (82.35%) were observed among bacteremic isolates. Levonadifloxacin demonstrated potent activity against MRSA, QRSA, and MR-CoNS strains with significantly lower minimum inhibitory concentration MIC50/90 values of 0.5/1 mg/L as compared with levofloxacin (8/32 mg/L) and moxifloxacin (2/8 mg/L). Conclusion Potent bactericidal activity coupled with low MICs support usage of levonadifloxacin for the management of BSIs caused by multidrug resistant Gram-positive bacteria.

scholarly journals “Logrolling” in Antarctic governance: Limits and opportunities

Polar Record ◽  
2020 ◽  
Vol 56 ◽  
Author(s):  
Jeffrey McGee ◽  
Bruno Arpi ◽  
Andrew Jackson
Keyword(s):  
Marine Protected Areas ◽  
International Institutions ◽  
Marine Resources ◽  
International Governance ◽  
Short Term ◽  
Current Case ◽  
Antarctic Marine ◽  
Antarctic Treaty ◽  
Kunlun Station ◽  
The Antarctic

Abstract The Antarctic Treaty System (ATS) is considered a successful example of international governance as it has managed tensions over sovereignty claims, avoided militarisation and dealt with marine resources and environmental protection. Recently, China’s influence and assertiveness in many international institutions have significantly grown. What effect this shift in the international politics will have upon Antarctic governance remains to be seen. However, to further thinking on this issue we explore two current case studies that reveal pressure points within the ATS. First, in the Commission for the Conservation of Antarctic Marine Living Resources, Australia has proposed marine protected areas off East Antarctica, to which China and several other states have objected. Second, in the Antarctic Treaty Consultative Meetings, China has proposed special management arrangements for the area around the “Kunlun” station, to which Australia and several other states have objected. Negotiation theory suggests “logrolling” (i.e. trade of mutual decision-making support across issue areas) can be an effective strategy to avoid diplomatic deadlocks. We therefore consider the merits of a logrolling strategy for the above issues. We find that while a logrolling strategy in the ATS might facilitate short-term diplomatic success, it would carry significant risks, including the weakening of existing norms.

scholarly journals Phytoplankton of the Curonian Lagoon as a New Interesting Source for Bioactive Natural Products. Special Impact on Cyanobacterial Metabolites

Biomolecules ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1139
Author(s):  
Donata Overlingė ◽  
Anna Toruńska-Sitarz ◽  
Marta Cegłowska ◽  
Agata Błaszczyk ◽  
Karolina Szubert ◽  
...  
Keyword(s):  
Natural Products ◽  
Serine Proteases ◽  
Ex Situ ◽  
Breast Adenocarcinoma ◽  
Curonian Lagoon ◽  
Bacterial Strains ◽  
Biotechnological Potential ◽  
Bioactive Natural Products ◽  
Field Samples ◽  
Sample Component

The bioprospecting of marine and brackish water systems has increased during the last decades. In this respect, microalgae, including cyanobacteria, and their metabolites are one of the most widely explored resources. Most of the bioactive compounds are isolated from ex situ cultures of microorganisms; however, analysis of field samples could also supply valuable information about the metabolic and biotechnological potential of microalgae communities. In this work, the activity of phytoplankton samples from the Curonian Lagoon was studied. The samples were active against antibiotic resistant clinical and environmental bacterial strains as well as against serine proteases and T47D human breast adenocarcinoma cells. No significant effect was found on Daphnia magna. In addition, using LC-MS/MS, we documented the diversity of metabolites present in field samples. A list of 117 detected cyanopeptides was presented. Cyanopeptolins constituted the largest class of cyanopeptides. As complex bloom samples were analyzed, no link between the observed activity and a specific sample component can be established. However, the results of the study showed a biotechnological potential of natural products from the Curonian Lagoon.

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