Biological Efficacy of Compounds from Stingless Honey and Sting Honey against Two Pathogenic Bacteria: An In Vitro and In Silico Study.

Honey inhibits bacterial growth due to the high sugar concentration, hydrogen peroxide generation, and proteinaceous compounds present in it. In this study, the antibacterial activity of stingless and sting honey against foodborne pathogenic bacteria isolated from spoiled milk samples was examined. The isolated bacterial strains were confirmed as Bacillus cereus and Listeriamonocytogenes through morphological, biochemical, and 16 s RNA analysis. Physiochemical characterizations of the honey samples revealed that both of the honey samples had an acidic pH, low water content, moderate reducing sugar content, and higher proline content. Through the disc diffusion method, the antibacterial activities of the samples were assayed and better results were observed for the 50 mg/disc honey. Both stingless and sting honey showed the most positive efficacy against Bacillus cereus. Therefore, an in silico study was conducted against this bacterium with some common compounds of honey. From several retrieved constituents of stingless and sting honey, 2,4-dihydroxy-2,5-dimethyl 3(2H)-furan-3-one (furan) and 4H-pyran-4-one,2,3-dihydro of both samples and beta.-D-glucopyranose from the stingless revealed high ligand-protein binding efficiencies for the target protein (6d5z, hemolysin II). The root-mean-square deviation, solvent-accessible surface area, the radius of gyration, root-mean-square fluctuations, and hydrogen bonds were used to ensure the binding stability of the docked complexes in the atomistic simulation and confirmed their stability. The combined effort of wet and dry lab-based work support, to some extent, that the antimicrobial properties of honey have great potential for application in medicine as well as in the food industries.

Reconstitution of a mini-gene cluster combined with ribosome engineering led to effective enhancement of salinomycin production in Streptomyces albus.

Salinomycin, an FDA-approved polyketide drug, was recently identified as a promising anti-tumour and anti-viral lead compound. It is produced by Streptomyces albus, and the biosynthetic gene cluster (sal) spans over 100 kb. The genetic manipulation of large polyketide gene clusters is challenging, and approaches delivering reliable efficiency and accuracy are desired. Herein, a delicate strategy to enhance salinomycin production was devised and evaluated. We reconstructed a minimized sal gene cluster (mini-cluster) on pSET152 including key genes responsible for tailoring modification, antibiotic resistance, positive regulation and precursor supply. These genes were overexpressed under the control of constitutive promoter PkasO* or Pneo . The pks operon was not included in the mini-cluster, but it was upregulated by SalJ activation. After the plasmid pSET152::mini-cluster was introduced into the wild-type strain and a chassis host strain obtained by ribosome engineering, salinomycin production was increased to 2.3-fold and 5.1-fold compared with that of the wild-type strain respectively. Intriguingly, mini-cluster introduction resulted in much higher production than overexpression of the whole sal gene cluster. The findings demonstrated that reconstitution of sal mini-cluster combined with ribosome engineering is an efficient novel approach and may be extended to other large polyketide biosynthesis.

Social distancing in advanced emergency medicine courses - can it work?

Introduction: The corona virus pandemic rendered most live education this spring term impossible. Many classes were converted into e-learning formats. But not all learning content and outcomes can readily be transferred into digital space. Project outline: Emergency medicine teaching relies on hands-on simulation training. Therefore, we had to devise a catalogue of measures, that would enable us to offer simulation training for Advanced Life Support. Summary of work: Strict hygienic rules including disinfection of hands, wearing personal protective gear at all times and disinfection of equipment were implemented. Group size and number of staff was reduced, introducing fixed student teams accompanied by the same teacher. Only large rooms with good ventilation were used. Under these conditions, we were allowed to carry out core Advanced Life Support simulations. Other content had to be transferred to online platforms. Discussion: Heeding general hygiene advise and using personal protective gear, a central cluster of simulations was carried out. Students and staff adhered to rules without complaint. No infections within faculty or student body were reported. Conclusion: It seems feasible to conduct core simulations under strict hygienic protocol.

Targeting the initiation and termination codons of SARS-CoV-2 spike protein as possible therapy against COVID-19: the role of novel harpagide 5-O-ß-D-glucopyranoside from Clerodendrum volubile P Beauv. (Labiatae).

The global spread of the coronavirus infections disease - 2019 (COVID-19) and the search for new drugs from natural products particularly from plants are receiving much attention recently. In this study, the therapeutic potential of a new iridoid glycoside isolated from the leaves of Clerodendrum volubile against COVID-19 was investigated. Harpagide 5-O-ß-D-glucopyranoside (HG) was isolated, characterised and investigated for its druglikeness, optimized geometry, and pharmacokinetics properties. Its immunomodulatory was determined by chemiluminescence assay using polymorphonuclear neutrophils (PMNs) in addition to T-cell proliferation assay. In silico analysis was used in determining its molecular interaction with severe acute respiratory syndrome coronavirus-2 (SARS-COV-2). HG displayed potent druglikeness properties, with no inhibitory effect on cytochrome P450 (1A2, 2C19, 2C9, 2D6 and 3A4) and a predicted LD50 of 2000 mg/kg. Its 1H-NMR chemical shifts showed a little deviation of 0.01 and 0.11 ppm for H-4 and H-9, respectively. HG significantly suppressed oxidative bursts in PMNs, while concomitantly inhibiting T-cell proliferation. It also displayed a very strong binding affinity with the translation initiation and termination sequence sites of spike (S) protein mRNA of SARS-COV-2, its gene product, and host ACE2 receptor. These results suggest the immunomodulatory properties and anti-SARS-COV-2 potentials of HG which can be explored in the treatment and management of COVID-19.Communicated by Ramaswamy H. Sarma.

Pulmonary delivery of nanostructured lipid carriers for effective repurposing of salinomycin as an antiviral agent.

Coronavirus disease outbreak caused a severe public health burden all over the world. Salinomycin (SAL) is a broad-spectrum antibiotic that had drawn attention in selective targeting of cancer and viral infections. Recent drug screen identified SAL as a potent antiviral agent against SARS-CoV-2. In this hypothesis, we discuss the potential of pulmonary delivery of SAL using nanostructured lipid carriers (NLCs) against SARS-CoV-2.

Potential Antiviral Options against SARS-CoV-2 Infection.

As of June 2020, the number of people infected with severe acute respiratory coronavirus 2 (SARS-CoV-2) continues to skyrocket, with more than 6.7 million cases worldwide. Both the World Health Organization (WHO) and United Nations (UN) has highlighted the need for better control of SARS-CoV-2 infections. However, developing novel virus-specific vaccines, monoclonal antibodies and antiviral drugs against SARS-CoV-2 can be time-consuming and costly. Convalescent sera and safe-in-man broad-spectrum antivirals (BSAAs) are readily available treatment options. Here, we developed a neutralization assay using SARS-CoV-2 strain and Vero-E6 cells. We identified the most potent sera from recovered patients for the treatment of SARS-CoV-2-infected patients. We also screened 136 safe-in-man broad-spectrum antivirals against the SARS-CoV-2 infection in Vero-E6 cells and identified nelfinavir, salinomycin, amodiaquine, obatoclax, emetine and homoharringtonine. We found that a combination of orally available virus-directed nelfinavir and host-directed amodiaquine exhibited the highest synergy. Finally, we developed a website to disseminate the knowledge on available and emerging treatments of COVID-19.