Silver nanoparticle biosynthesis utilizing Ocimum kilimandscharicum leaf extract and assessment of its antibacterial activity against certain chosen bacteria.

The use of plants in the biological production of silver nanoparticles for antibacterial applications is a growing field of research. In the current work, we formulated Ocimum kilimandscharicum extracts using silver nanoparticles, and evaluated its potential antibacterial activity. Aqueous and methanol plant extracts were used to reduce silver nitrate at different time intervals (30 to 150 minutes) and pH (2 to 11). The UV-visible absorption spectrum recorded for methanol and aqueous extracts revealed a successful synthesis of AgNPs for methanol and aqueous extracts. The antimicrobial activity of the AgNPs was evaluated against Escherichia coli ATCC 25922, Salmonella choleraesuius ATCC 10708, and Staphylococcus aureus ATCC 25923 The best inhibition zone for the methanol and aqueous-mediated AgNPs, ranging from 12 ± 1 to 16 ± 1mm. Additionally, the methanol and aqueous extract silver nanoparticles had the same Minimum Inhibitory Concentration (6.25 ± 0.00 mg/ml), whereas the Minimum Bactericidal Concentrations were 12.5 ± 0.00 and 25 ± 0.00 mg/ml, respectively. The highest inhibition zone of 16 ± 1 mm was observed against Salmonella choleraesuius with 50 ± 0.00 mg/ml aqueous silver nanoparticles. The results show that the silver nanoparticles made with Ocimum kilimandscharicum have antibacterial action against those microorganisms.

Phytochemical Screening and GC-MS Analysis of Methanolic and Aqueous Extracts of Ocimum kilimandscharicum Leaves.

Kenyans have long utilized Ocimum kilimandscharicum, an East African permanent evergreen plant, to treat measles, stomachaches, diarrhea, mosquito bites (anti-insect), congested chest, cough, and colds. Using conventional qualitative and quantitative techniques, this study was done to identify the secondary metabolites in O. kilimandscharicum leaf extracts. The chemical content of the crude extracts from the leaves of O. kilimandscharicum has also been investigated and characterized using gas chromatography-mass spectrometry (GC-MS). By using a 1:20 dilution in methanol, in cold maceration, a fine powder of O. kilimandscharicum was first extracted then filtered and concentrated after 72 h utilizing a rotary evaporator. By using also a 1:20 dilution in water at 80 °C, a fine powder of O. kilimandscharicum was extracted and then filtrated and lyophilized 1 h later. Each extract underwent further gas chromatography-mass spectrometry testing. We found that both extracts contain secondary metabolites such as alkaloids, phenolics, flavonoids, saponins, and tannins. However, the overall amount of phytochemicals in each solvent varied significantly. Total phenolics contents (TPCs) were 5.6 ± 1.20 and 10.8 ± 1.00 mg, total flavonoid contents (TFCs) were 8.2 ± 0.4 and 39.6 ± 2.2 mg, total tannin contents (TTCs) were 0 ± 0.00 and 10.5 ± 0.4 mg, the total alkaloid content (TAC) was 49.2 ± 0.40%, and the total saponin content (TSC) was 38 ± 2.00%. Additionally the gas chromatography-mass spectrometry, revealed a number of high- and low-molecular-weight bioactive molecules at various concentrations for each extract. We also found an inhibitory effect on adhP and chbR gene expression of Staphylococcus aureus and Salmonella choleraesuius, respectively. Hence, these chemicals could potentially have a biological and pharmacological significance. Therefore, the discovery of many physiologically active chemicals in the leaf extracts of O. kilimandscharicum justifies future biological and pharmaceutical research.

Confronting the human papillomavirus-HIV intersection: Cervical cytology implications for Kenyan women living with HIV.

Background: High-risk human papillomavirus (HR-HPV) is the primary cause of cervical cancer, leading to over 311 000 global deaths, mainly in low- and middle-income countries. Kenyan women living with HIV (WLHIV) face a disproportionate burden of HR-HPV. Objectives: We determined the prevalence of HR-HPV infections and their association with cervical cytology findings among Kenyan WLHIV. Method: We conducted a cross-sectional study among WLHIV attending the HIV care and treatment clinic at the Kenyatta National Hospital (KNH), Kenya's national referral hospital. Study nurses collected a cervical sample with a cytobrush for HR-HPV genotyping using Gene Xpert® assays and HPV Genotypes 14 Real-TM Quant V67-100FRT. Bivariate analysis explored the associations. Results: We enrolled 647 WLHIV (mean age of 42.8 years), with 97.2% on antiretroviral therapy (ART) and 79% with a suppressed viral load (< 50 copies/mL plasma). The prevalence of any and vaccine-preventable HR-HPV was 34.6% and 29.4%, respectively, with HPV 52 being the most common genotype (13.4%). Among WLHIV with HR-HPV infections, 21.4% had abnormal cervical cytology. Women with multiple HR-HPV infections were more likely to have abnormal cytology compared to those with single HR-HPV infections (34.9 vs 9.3%, adjusted odds ratio [aOR] = 6.2, 95% confidence interval [CI]: 2.7-14.1, P = 0.001). Women with HR-HPV infection (single or multiple) were more likely to be on the second-line ART regimen compared to those without HR-HPV infections (53.1% vs 46.7%, aOR = 2.3, 95% CI: 1.3-4.1, P = 0.005). Conclusion: Among WLHIV at KNH, abnormal cytology was common and more frequent among women with multiple HR-HPV infections.

Genetic diversity and population structure of wild and cultivated Crotalaria species based on genotyping-by-sequencing.

Crotalaria is a plant genus that is found all over the world, with over 700 species of herbs and shrubs. The species are potential alternative food and industrial crops due to their adaptability to different environments. Currently, information on the genetic diversity and population structure of these species is scanty. Genotyping-by-sequencing (GBS) is a cost-effective high-throughput technique in diversity evaluation of plant species that have not been fully sequenced. In the current study, de novo GBS was used to characterize 80 Crotalaria accessions from five geographical regions in Kenya. A total of 9820 single nucleotide polymorphism (SNP) markers were obtained after thinning and filtering, which were then used for the analysis of genetic diversity and population structure in Crotalaria. The proportion of SNPs with a minor allele frequency (maf) > = 0.05 was 45.08%, while the Guanine-Cytosine (GC) content was 0.45, from an average sequence depth of 455,909 reads per base. The transition vs transversion ratio was 1.81 and Heterozygosity (He) ranged between 0.01-0.07 in all the sites and 0.04 to 0.52 in the segregating sites. The mean Tajima's D value for the population was -0.094, suggesting an excess of rare alleles. The fixation index (Fst) between the different populations based on the Wright Fst (1943) ranged from 0.0119 to 0.066 for the Eastern-Western and Nairobi-Western populations. Model based techniques of population structure analysis including structure, k-means and cross-entropy depicted eight clusters in the study accessions. Non-model based techniques especially DAPC depicted poor population stratification. Correspondence Analysis (CA), Principal coordinate analyses (PCoA) and phylogenetic analysis identified a moderate level of population stratification. Results from this study will help conservationists and breeders understand the genetic diversity of Crotalaria. The study also provides valuable information for genetic improvement of domesticated species.

Increase in the Immune Response in Balb/c Mice after the Co-Administration of a Vector-Based COVID-19 Vaccine with Cytosine Phosphoguanine Oligodeoxynucleotide.

The effects of cytosine phosphoguanine oligodeoxynucleotides (CPG ODNs) on immune response have been demonstrated for different vaccines; however, such information is limited for the vector-based Coronavirus disease 2019 (COVID-19). This paper aims to demonstrate the potential effect of CPG ODNs on immunological response against the vector-based COVID-19 vaccine on Balb/c mice using a JNJ-78436735 Ad26.COV2-S recombinant as a model vaccine. A total of 18 BALB/c mice clustered into six groups were used. All groups were observed for 14- and 28-days post immunization. Qualitative determination of IgG was performed using indirect Enzyme-Linked Immunosorbent Assay (ELISA) and qPCR for cytokine profiling. A significant (p ≤ 0.001) rise in antibody response was observed for groups 3 and 4, who also showed increased expression levels of Tumor Necrosis Factor (TNF) and Interferon Gamma (IFN-γ). Immunological parameters for toxicity were normal in all treatment groups. We conclude that supplementing vector-based COVID-19 vaccines with CpG ODNs has the potential to boost the body's immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

Establishment and evaluation of a loop-mediated isothermal amplification (LAMP) assay for the semi-quantitative detection of HIV-1 group M virus.

The past decade has witnessed a dramatic increase of anti-retroviral treatment of human immunodeficiency virus (HIV) infected patients in many African countries. Due to costs and lack of currently available commercial viral load assays, insufficient attention has been paid to therapy monitoring through measurement of plasma viral load. This challenge of patient monitoring by tests as viral load, CD4 cell count, and finally HIV drug resistance could reverse achievements already made against HIV/AIDS infection. Loop-mediated isothermal amplification (LAMP) has been shown to be simple, rapid and cost-effective, characteristics which make this assay suitable for viral load monitoring in resource limited settings. This paper describes a revised LAMP assay using primers in the HIV-1 integrase region. The assay can be used for semi-quantitative measurement of HIV-1 group M viral load. The lower limit of detection (LLOD) was determined as 1200copies/mL and lower limit of quantitation (LLOQ) at 9800copies/mL. Sensitivities of 82 and 86% (in 135 and 99 plasma samples respectively from Kenya) and 93% (in 112 plasma samples from Germany) and specificities of 99 and 100% were realized. HIV-1 group O and HIV-2 virus samples were not detected. This LAMP assay has the potential for semi-quantitation of HIV-1 group M viral load in resource limited countries. There is still a need for further improvement by refinement of primers in respect to detection of HIV-1 group M non-B virus.