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Objectives: To explore the antibacterial activity of thymoquinone (TQ), a quinone extracted from Nigella sativa. Methods: This study was conducted from May 2019 to March 2020 at the Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Khalid University, Abha, Saudi Arabia. The antimicrobial activity, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) of TQ were determined using an agar well diffusion method and broth microdilution assays, and the synergistic effect was evaluated using antibiotics in parallel. The disruptive effect of TQ on bacterial cell membranes was determined using scanning electron microscopy. The antivirulence properties of TQ, which include adherence and biofilm formation, were also investigated using adherence and biofilm formation assays, respectively. Results: Thymoquinone demonstrated bactericidal efficacy against 4/14 bacterial strains, with MIC range of 1.04-8.3 µg/mL and and MBC range of 10.41–66.66 µg/mL. Thymoquinone showed synergism against Klebsiella pneumoniae, Staphylococcus epidermidis (American Type Culture Collection 12228), Staphylococcus aureus, and Staphylococcus epidermidis in combination with the tested antibiotics. Thymoquinone inhibited bacterial adhesion by 39%-54%, 48%-68%, and 61%-81% at 0.5 × MIC, 1 × MIC, and 2 × MIC, respectively. The tested bacterial strains significantly inhibited biofilm formation after treatment with various concentrations of TQ for 24 and 48 hours. Conclusion: The combinatory effect of TQ with antimicrobials should be considered when developing new antimicrobial therapy regimens to overcome multidrug-resistant.

Pneumocystis jirovecii (PCP) remains a significant cause of mortality and morbidity in patients with respiratory infections. Accurate diagnosis of PCP is still a diagnostic challenge. Hence, the main objectives were to study the incidence of Pneumocystis Jirovecii pneumonia infection among respiratory problems patients and to compare the real-time quantitative PCR technique with various diagnostic methodologies. Patients who have respiratory symptoms of PCP like breathlessness, cough, and fever were enrolled. Bronchoalveolar lavage (BAL) samples were collected and homogenized, and then smears were prepared for examination by Gomorimethanamine silver staining (GMSS), Immunofluorescent staining (IFAT), Toludine blue O (TBO), and Giemsa staining. Further, RT-PCR was also performed for the detection of PCP. The mean patients’ age was 52 (SD ±16) years. 41% were female, and 59% of the patients were male. Weight loss (80%), fever (92%), cough (100%), and dyspnea (76%) were the most common complaints. Twenty-eight patients have been diagnosed with pulmonary infiltrates using chest X-ray. Out of 100 patients, 35% were positive for PCP. The organism was detected using IFAT in all the 35 specimens, 15 of 35 (42.86%) by GMSS, 8 of 35 (17.6%) by Giemsa stain, and 1 of 35 (2.8%) was detected by TBO stains. RT-PCR showed that 39 patients was found to be positive for PCP. Thirty-five of these 39 patients had a positive IFAT (89.74%); the IFAT was negative or undefined in 4 samples. All 39 patients (100%) had signs and symptoms for PCP. Our results suggest that RT-PCR is still the most highly sensitive method for Pneumocystis Jirovecii detection. In poor resource settings where RT-PCR and IFAT is not available, diagnosis of Pneumocystis jirovecii pneumonia remains a complicated issue. In settings where RT-PCR & IFAT are not available, GMSS staining may be the next best choice to detect PCP.

Continuous urban developments have resulted in increased demand for street furniture, one of which is street light columns. Artificial light at night (ALAN) pose significant impacts on insect diversity in urban and rural areas. The ALAN is a significant driver of decline in insect diversity. This study evaluated the impact of light intensity and sky quality at night on insect diversity in rural and urban areas of the Asir province, Saudi Arabia. Insect traps were installed in both areas during night. Light intensity of nearby road lamps was measured using light meter, while sky quality was measured using sky quality meter. Rural areas exhibited low light intensity (10.33 flux/f.candle) and good sky quality (18.80 magnitude/arcsec2). Urban areas exhibited intense light (89.33 flux/f.candle) and poor sky quality (15.49 magnitude/arcsec2). Higher insect diversity was recorded for rural areas where insects belonging to seven orders (i.e., Diptera, Lepidoptera, Hemiptera, Hymenoptera, Coleoptera, Neuroptera, and Dermaptera) were collected. However, insects of four orders (i.e., Diptera, Lepidoptera, Hemiptera, and Neuroptera) were found in urban areas indicating low diversity. Lepidopteran insects were frequently recorded from rural areas indicating they are attracted to artificial light. It is concluded that excessive ALAN and poor sky quality at night disrupt insect biodiversity. Therefore, ALAN and sky quality must be considered responsible for decline in insect biodiversity along with other known factors.

The aim of the present 6-months' follow-up study was to assess the influence of single versus multiple sessions of photodynamic therapy (PDT) as adjunct to scaling and root planning (SRP) on periodontopathogenic bacteria in patients with periodontitis.Forty-five patients with periodontitis were included. The patients were randomly divided into 3 groups. In groups 1 (n = 15), 2 (n = 15) and 3 (n = 15), the patients under went SRP with PDT at (a) baseline; (b) baseline and after 1-month; and (c) baseline and after 1- and 3-months. Peri-implant plaque index (PI), bleeding on probing (BOP), probing depth (PD), clinical attachment loss (CAL) and marginal bone loss (MBL) were measured at baseline and 6-months follow-up. Counts of Porphyromonas gingivalis, Treponema denticola, Prevotella intermedia, Fusobacterium nucleatum and Aggregatibacter Actinomycetemcomitans were determined before SRP and at 4- and 6-months follow-up.All patients had grade-B periodontitis. There was no statistically significant difference in age and gender in all groups. At- 6-months' follow-up, patients that underwent SRP once showed significantly higher counts of periodontopathogenic bacteria in the oral biofilm compared with patients that received photobiomodulation twice or three times (P0.05). There was no significant difference in the periodontal parameters and counts of gram-negative bacteria in patients that received photobiomodulation 2 or 3 times.At least 2 sessions of PDT following baseline SRP is essential to achieve a significant reduction in the counts of subgingival bacteria in periodontitis patients over a 6-month follow-up period.

The current COVID-19 pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Globally, this pandemic has affected over 111 million individuals and posed many health and economic challenges. Much research effort is dedicated to discovering new treatments to address the associated challenges and restrict the spread of SARS-CoV-2. Since SARS-CoV-2 is a positive-strand RNA virus, its replication requires the viral RNA-dependent RNA polymerase (RdRp) enzyme. In this study, we report the discovery of new potential RdRp enzyme inhibitors based on computer modeling and simulation methodologies. The antiviral ZINC database was utilized for covalent docking virtual screening followed by molecular interaction analyses based on reported hot spots within the RdRp binding pocket (PDB: 7BV2). Eleven molecules, ZINC000014944915, ZINC000027556215, ZINC000013556344, ZINC000003589958, ZINC000003833965, ZINC000001642252, ZINC000028525778, ZINC000027557701, ZINC000013781295, ZINC000001651128 and ZINC000013473324, were shown to have the highest binding interactions. These molecules were further assessed by molecular dynamics (MD) simulations and absorption, distribution, metabolism, excretion, and toxicity (ADMET) studies. The results showed that all 11 molecules except ZINC000027557701 formed stable complexes with the viral RdRp and fell within the accepted ADMET parameters. The identified molecules can be used to design future potential RdRp inhibitors.

Background and Objectives: The aim of this study was to compare the effects of low-level laser therapy and continuous microwave diathermy on the growth of Gram-negative and Gram-positive bacteria and to establish their efficacy as an alternative therapeutic modality. Materials and methods: Laser fluence of 13 Joules (J)/cm2, 18 J/cm2 and 30 J/cm2 were used against several bacterial strains. Microwave dosages of 25, 50 and 100 watts (W) were used, respectively. Results: A significant difference between the three groups was observed using repeated analysis of variance (RANOVA) (F value: 0.74, and p value: 0.001). The Greenhouse&ndash, Geisser correction (GG) revealed significant results for laser irradiation alone. However, effect size calculation showed effects with microwave diathermy as well as laser fluence. Conclusions: Low-level laser therapy appears to be an effective modality of treatment when compared with continuous microwave diathermy on the Gram-negative and the Gram-positive bacterial strains tested. Microwave diathermy revealed large and medium effects on the bacterial cell counts with dominant effects on Gram-negative strains.

Phage-displayed random peptide libraries are widely used for identifying peptide interactions with proteins and other substrates. Selection of peptide ligands involves iterative rounds of affinity enrichment. The binding properties of the selected phage clones are routinely tested using immunoassay after propagation to high titre in a bacterial host and precipitation using polyethylene glycol (PEG) and high salt concentration. These immunoassays can suffer from low sensitivity and high background signals. Polysorbate 20 (Tween(®) 20) is a non-ionic detergent commonly used in immunoassay washing buffers to reduce non-specific binding, and is also used as a blocking reagent. We have observed that Tween 20 enhances non-specific M13 library phage binding in a peptide-independent manner. Other non-ionic detergents were also found to promote significant, dose-dependent non-specific phage binding in ELISA. This effect was not observed for assays using phage concentrated by ultracentrifugation, suggesting that interactions occur between detergents and the PEG-precipitated phage, irrespective of the displayed peptide motif. This artefact may impact on successful affinity selection of peptides from phage-display libraries. We propose alternative methods for screening phage libraries for identifying binding interactions with target ligands.