Antimicrobial drug resistance is a rising concern in the treatment of infectious diseases and necessitates the need for discovery of novel, potent antimicrobial compounds to combat antibiotic resistance. Since natural...Antimicrobial drug resistance is a rising concern in the treatment of infectious diseases and necessitates the need for discovery of novel, potent antimicrobial compounds to combat antibiotic resistance. Since natural environment remains a potential source of novel antimicrobial products, this preliminary study was performed to test the potential of soils from Kericho County for antibiotic-producing Actinomycetes. Soil samples (214) were randomly collected from virgin soils of Kipkelion East, Kipkelion West, Belgut, Ainamoi, Sigowet and Bureti sub-counties in Kericho County from a depth of between 11 cm - 16 cm from the surface of the soil profile. A total of 107 Actinomycetes were isolated and screening was done using modified agar disc diffusion method of which only 39 (36.4%) showed antimicrobial activity against five of the six test isolates that included reference strains Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922) and Candida albicans (ATCC 90028) and three clinical strains Trichophyton mentagrophyte, Microsporum gypseum and Methicillin Resistant Staphylococcus aureus. Two of the isolates showed activity against MRSA and four isolates showed a higher potency than the standard drug Chloramphenicol (30 μg) against S. aureus. Most of the isolates (41.0%) also showed good antimicrobial activity against T. mentagrophyte, though they lower than the control drug Itraconazole (2 μg/ml), they were statistically significant. DNA from the isolates was extracted and the 16S rRNA gene was amplified using primers specific for Actinomycetes. The amplified gene was sequenced and phylogeny analysis was done. The 16S rRNA gene was able to be amplified in only 15 of these isolates. Sequencing showed that 93.3% were of the genus Streptomyces while 6.7% were of the genus Rhodococcus. From the results, the soils from this region harbour Actinomycetes that may have good potential of producing novel antibiotics against gram positive bacteria and dermatophytes.展开更多
Background: Nanotechnology symbolizes a broad discipline with enormous potential in cancer treatment bridging one of the bottlenecks of traditional approaches in cancer therapy which is an inability to deliver adequat...Background: Nanotechnology symbolizes a broad discipline with enormous potential in cancer treatment bridging one of the bottlenecks of traditional approaches in cancer therapy which is an inability to deliver adequate quantities of anti-cancer drugs to the tumor area. Studies on nanoparticles indicate their importance in cancer angiogenesis and metastasis. Aim: The present study assessed anti-angiogenesis and anti-metastatic effects of biogenic silver nanoparticles (AgNPs) synthesized from neem plant (Azadirachta indica). Methods: Chicken chorioallantoic membrane (CAM) and two-dimensional (2D) wound healing assays were used to study anti-angiogenic and anti-metastatic effects of the AgNPs respectively. Twenty-four fertilized eggs were divided into four groups: two biogenic AgNPs treatments at 100 μg/ml and 200 μg/ml;negative control (1% DMSO) and positive control (cyclophosphamide). On day 8 of incubation, filter discs impregnated with different concentration levels of the treatments were placed on the CAM. On day 12 of incubation, the CAMs were imaged using a stereomicroscope, scaled using ImageJ, and different morphometric and spatial parameters computed using AngioTool software. Vessel area, vessel percent area, total number of junctions, total vessel length, average vessel length, mean lacunarity, and junction density were measured. The crown-rump length (CRL) and fetal weight were also recorded on day 16 of incubation. In order to determine relative gene expression profiles of iNOS and VEGF, total RNA was extracted from the CAM, and qRT-PCR was performed with β-Actin as a reference gene. For the 2D wound healing assay, DU145 human prostate cells were grown in Dulbecco’s Modified Eagle’s Medium supplemented with 10% Fetal Bovine Serum. Results: Biogenic AgNPs demonstrated anti-angiogenic effects in a dose-dependent manner in the parameters generated from the CAM images. Also, qRT-PCR revealed down-regulation of iNOS and VEGF genes. The 2-dimensional wound healing assay showed inhibition of migration and motility of the DU145 cells for the 72-hours of assessment. Conclusion: The present study postulates that the biogenic AgNPs can prevent angiogenesis by inactivation of VEGF-NO and VEGF/VEGF-R pathways while inhibiting cell migration and metastasis.展开更多
文摘Antimicrobial drug resistance is a rising concern in the treatment of infectious diseases and necessitates the need for discovery of novel, potent antimicrobial compounds to combat antibiotic resistance. Since natural environment remains a potential source of novel antimicrobial products, this preliminary study was performed to test the potential of soils from Kericho County for antibiotic-producing Actinomycetes. Soil samples (214) were randomly collected from virgin soils of Kipkelion East, Kipkelion West, Belgut, Ainamoi, Sigowet and Bureti sub-counties in Kericho County from a depth of between 11 cm - 16 cm from the surface of the soil profile. A total of 107 Actinomycetes were isolated and screening was done using modified agar disc diffusion method of which only 39 (36.4%) showed antimicrobial activity against five of the six test isolates that included reference strains Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922) and Candida albicans (ATCC 90028) and three clinical strains Trichophyton mentagrophyte, Microsporum gypseum and Methicillin Resistant Staphylococcus aureus. Two of the isolates showed activity against MRSA and four isolates showed a higher potency than the standard drug Chloramphenicol (30 μg) against S. aureus. Most of the isolates (41.0%) also showed good antimicrobial activity against T. mentagrophyte, though they lower than the control drug Itraconazole (2 μg/ml), they were statistically significant. DNA from the isolates was extracted and the 16S rRNA gene was amplified using primers specific for Actinomycetes. The amplified gene was sequenced and phylogeny analysis was done. The 16S rRNA gene was able to be amplified in only 15 of these isolates. Sequencing showed that 93.3% were of the genus Streptomyces while 6.7% were of the genus Rhodococcus. From the results, the soils from this region harbour Actinomycetes that may have good potential of producing novel antibiotics against gram positive bacteria and dermatophytes.
文摘Background: Nanotechnology symbolizes a broad discipline with enormous potential in cancer treatment bridging one of the bottlenecks of traditional approaches in cancer therapy which is an inability to deliver adequate quantities of anti-cancer drugs to the tumor area. Studies on nanoparticles indicate their importance in cancer angiogenesis and metastasis. Aim: The present study assessed anti-angiogenesis and anti-metastatic effects of biogenic silver nanoparticles (AgNPs) synthesized from neem plant (Azadirachta indica). Methods: Chicken chorioallantoic membrane (CAM) and two-dimensional (2D) wound healing assays were used to study anti-angiogenic and anti-metastatic effects of the AgNPs respectively. Twenty-four fertilized eggs were divided into four groups: two biogenic AgNPs treatments at 100 μg/ml and 200 μg/ml;negative control (1% DMSO) and positive control (cyclophosphamide). On day 8 of incubation, filter discs impregnated with different concentration levels of the treatments were placed on the CAM. On day 12 of incubation, the CAMs were imaged using a stereomicroscope, scaled using ImageJ, and different morphometric and spatial parameters computed using AngioTool software. Vessel area, vessel percent area, total number of junctions, total vessel length, average vessel length, mean lacunarity, and junction density were measured. The crown-rump length (CRL) and fetal weight were also recorded on day 16 of incubation. In order to determine relative gene expression profiles of iNOS and VEGF, total RNA was extracted from the CAM, and qRT-PCR was performed with β-Actin as a reference gene. For the 2D wound healing assay, DU145 human prostate cells were grown in Dulbecco’s Modified Eagle’s Medium supplemented with 10% Fetal Bovine Serum. Results: Biogenic AgNPs demonstrated anti-angiogenic effects in a dose-dependent manner in the parameters generated from the CAM images. Also, qRT-PCR revealed down-regulation of iNOS and VEGF genes. The 2-dimensional wound healing assay showed inhibition of migration and motility of the DU145 cells for the 72-hours of assessment. Conclusion: The present study postulates that the biogenic AgNPs can prevent angiogenesis by inactivation of VEGF-NO and VEGF/VEGF-R pathways while inhibiting cell migration and metastasis.
