Bioactivity guided isolation of the antifungal components in sawdust extracts of Piptadeniatrum africanum, and Terminalia ivorensis

Aim: The antifungal activities of extracts from fresh sawdust of Piptadeniatrum africanum,and Terminalia ivorensis was determined using the agar well diffusion method. Aqueous, methanol, chloroform,and n-hexane extracts obtained from the sawdust samples were tested against fungi isolated from some decayed wood samples.Methodology and Results: Fungal isolates included: Aspergillus. niger, Aspergillus. flavus, Aspergillus. fumigates, Aspergillus. wentii, Aspergillus. tamari, and Penicillium. chrysogenum (please write the microorganisms’ name in full when first time introducing them). Results of inhibitory activities showed that the chloroform extracts showed the highest inhibitory abilities with zones of inhibition ranging from 14 mm-24 mm for P. africanum, and 11 mm-15 mm for T. ivorensis. However, the aqueous extracts exhibited the least antifungal activity with zones of inhibition ranging between 10 mm-13 mm and 8 mm-11 mm respectively.Conclusion, significance and impact of study: The major secondary plant metabolites identified are alkaloids, anthraquinones, anthraglycosides, arbutin, glycosides, flavonoids, phenolics, saponins, coumarins and valepotriates. The antifungal components in P. africanum were identified to be 3, 7, 8, 3'–Tetramethoxy-6–C-methyl-5, 4'–dihydroxyflavone and 3–methoxy–6–C–methyl–3',4',5,7,8–pentahydroxyflavone while Terminalia ivorensis contained 5,7,8-Trihydroxy-2′5′-methoxy-3′,4′-methylenedioxyisoflavanone as the bioactive component

In vitro Synergy and Time-kill Assessment of Interaction between Kanamycin and Metronidazole against Resistant Bacteria

Purpose: To evaluate the in vitro effects of combining kanamycin and metronidazole against resistant bacteria.Methods: The influence of combining kanamycin and metronidazole against Gram-positive and  Gramnegative bacteria was assessed by agar diffusion,  checkerboard and time-kill assays.Results: The test isolates were highly resistant, with minimum inhibitory concentration (MIC) ranging between 15.63 and >250 μg/ml for kanamycin, and 15.63 and 125 μg/ml for metronidazole. The antibacterial combinations resulted in drastic decrease in MIC with increased antibacterial activity that indicated synergistic interaction against all the bacteria except Acinetobacter calcaoceuticus UP, Enterobacter cloacae ATCC 13047 and Shigella flexneri KZN. Fractional inhibitory  concentration index (FICI) showed synergy ranging from 0.31 to 0.50, additive interaction with FICI ranging from 0.53 to 1.25 and absence of antagonistic  interaction. Escherichia coli ATCC 25922, Enterococcus faecalis ATCC 29212, Bacillus cereus ATCC 10702, Enterobacter cloacae ATCC 13047, Klebsiella  pneumoniae ATCC 10031, Acinetobacter calcoaceuticus UP and Micrococcus luteus were totally eliminated by the antibacterial combinations within 24 h of  incubation. The lack of antagonism between these antibacterial agents in checkerboard and time-kill assays suggest that kanamycin may be effective in both monotherapy and combination therapy.Conclusion: The study indicates the potential beneficial value of combining kanamycin and metronidazole in the treatment of microbial infections in clinical settings.Keywords: Drug-drug interactions, Synergy, Time-kill, Fractional inhibitory concentration index, Kanamycin, Metronidazole, Microbial resistanc

Nursery Pest Management of Phytolyma lata Walker (Scott) Attack on Iroko (Milicia excelsa Welw C. C. Berg) Seedlings

The establishment of plantations of Milicia excelsa has been constrained by the gall-forming psyllid Phytolyma lata Walker (Scott) that causes extensive damage to young plants. We present findings of an experiment aimed at preventing Phytolyma attack on Milicia seedlings in the nursery using chemical control and physical barrier (screen house). Ninety, 6-month old seedlings of uniform growth were selected from a population of potted seedlings obtained from the same seed source. Thirty seedlings were placed in a screen house (SHS), while thirty seedlings (TRT) were placed in the open nursery under direct sunlight and treated fortnightly with a low concentration (0.05%) of water-based insecticide (Lambda-Cyhalothrin). As control (UNT), 30 seedlings were placed in the open nursery without any treatment. The survival, height and collar diameter of the seedlings were measured fortnightly for 24 weeks. After 10 weeks, the untreated seedlings were attacked by Phytolyma with evidence of leaf gall formation. Though, all UNT seedlings were attacked by the insect no, mortality was recorded during the study, while no gall formation occurred in the TRT and SHS seedlings. There was no significant difference in the collar diameter growth with 90.71%, 97.73%, and 115.48% increase in UNT, TRT and SHS seedlings, respectively. On the other hand, there were significant differences in the total height with 21.98%, 58.19%, increase in TRT and SHS, respectively; while UNT seedlings experienced a negative height growth of -0.27%. The provision of a physical barrier proved to be the most effective management strategy to prevent Phytolyma infestation, while chemical control was a successful alternative.Key Words: Iroko, gall formation, screen house, Lambda-Cyhalothrin, Phytolym

Phytoremediation of diesel and spent engine oil contaminated soil using Kariya (Hildergardia barteri Mast.) seedlings

Using a completely randomized design experiment, the effect of different levels of diesel and spent engine oil contamination (0 mL/kg, 25 mL/kg, 50 mL/kg and 75 mL/kg of soil) on growth performance (seedling height, collar diameter, number of leaves and biomass accumulation) of Hildergardia barteri seedlings were assessed for twelve weeks. The concentration of Lead, Nickel, Copper and Zinc in the plant parts were also determined. Data were analysed using descriptive and inferential statistics at P<0.05 level of significance. There were significant differences in the effects of diesel and spent engine oil on growth performance of seedlings based on contamination levels. Control treatment had the highest height (92.43±5.13 cm), collar diameter (16.23±0.98 mm), number of leaves (11.21±0.47) and total biomass (33.01±12.79 g). Seedlings exposed to 50 mL/kg treatments had the least height (diesel oil: 78.21±7.22 cm; spent engine oil: 79±6.24 cm); those exposed to 75 mL/kg contamination had the least collar diameter (diesel oil: 8.85±1.05 mm, spent engine oil: 12.02±1.01 mm), while seedlings treated with 50 mL/kg diesel oil (2.21±0.37) and 75 mL/kg spent engine oil (4.79±0.55) had the lowest number of leaves. Heavy metal bio-accumulation ranges were: Lead: 0.17-0.39 mg/kg, Nickel: 0.09–0.45 mg/kg, Copper: 0.54–1.08 mg/kg, Zinc: 0.88–1.58 mg/kg. The ability of the seedlings to survive and bio-accumulate heavy metals indicate the potential phytoremediation capabilities of Hildergardia barteri. Keywords: phytoextraction, hydrocarbon derivatives, growth inhibition, Hildergardia barter

Compressive strength in Heartwood Extract of Teak (HWE) treated hardwoods after exposure to white rot attack

Wood samples of Triplochiton scleroxylon and Gmelina arborea obtained from Omo Forest Reserve, South West Nigeria were treated with Heartwood Extract of Teak (HWE) and cuprinol-clear. The wood blocks were inoculated with two white rot fungi; Pleurotus squarrosullus and Lentinus subnudus for 12 weeks. Absorption of chemicals were determined at two concentration levels while resistance to decay was tested using Maximum Compressive Strength parallel to grain (MCS//). Data obtained were analyzed using ANOVA and descriptive statistics. Within wood blocks of the same species, absorption of both HWE and cuprinol-clear were not significantly different at both 4% and 8% concentrations. In both preservatives G.arborea test bocks produced higher MCS// than test blocks of T. scleroxylon. HWE was effective in reducing the impact of white rot in Gmelina arborea and Triplochiton scleroxylon.Keywords: Heartwood extract, Gmelina arborea, Triplochiton scleroxylon, White rot fungi, Compressive strength. 

Production dynamics of extracellular protease from Bacillus species

Screening and isolation of proteolytic bacteria were carried out from soil samples of Ikogosi warm spring (SW, Nigeria). Eighteen isolates were positive on skim milk agar (10%) of which fifteen produced protease in culture broth. Three isolates, identified as Bacillus macerans IKBM-11, B. licheniformis IKBL-17 and B. subtilis IKBS-10, were selected for further study. These Bacillus species could grow up to 65&#176C within a broad pH range of 5 to 10 with an optimal growth temperature and pH at 60&#176C and 8.0, respectively. For the three Bacillus species, protease production occurred between 37&#176C and 65&#176C and pH 5 to 10. Maximum growth and maximum enzyme production was observed at 48 h when grown in 50 ml medium (pH 8.0) under shaking condition at 60&#176C. The results showed that Bacillus species under study are good producers of extracellular protease at high temperature. This might be an indication that proteases produced would be thermostable. Keywords Protease; proteolytic bacteria; Bacillus macerans; Bacillus licheniformis; Bacillus subtilisAfrican Journal of Biotechnology Vol. 4 (8), pp. 776-77

Production of thermostable and organic solvent-tolerant alkaline protease from Bacillus coagulans PSB-07 under different submerged fermentation conditions

An alkaliphilic bacterium producing organic solvent-tolerant and thermostable alkaline protease was isolated from poultry litter site and identified as Bacillus coagulans PSB-07. Protease production under different submerged fermentation conditions were investigated with the aim of optimizing yield of enzyme. B. coagulans PSB-07 produced protease optimally at the beginning of stationary phase over broad pH range of 6.0 to 11.0 and temperature range of 30 to 50°C. The optimum enzyme production was at 37°C and pH 8.0. The media composition that supported maximum yield of protease (760.4 U/ml) contained sucrose (0.5%), peptone (0.75%), NaCl (0.05%) and MgSO4.7H2O (0.01%). The protease had optimum activity at 60°C and pH 8.0 with casein as substrate. The enzyme was stable over a broad pH of 6.0 to 12.0 and showed good thermostability retaining 91.4 and 50.5% of its original activity after incubation at 50 and 60°C for 60 min at pH 8.0 in the presence of CaCl2. The protease was strongly activated by metal ions, Ca2+ and Mg2+. The enzyme showed remarkable activity and stability in the presence of all organic solvents studied except benzene. The exhibited properties of the protease suggest the suitability of the enzyme for applications in peptide synthesis, detergent formulation and bio-transformation in non-aqueous medium.Keywords: Alkaline protease, Bacillus coagulans PSB-07, organic solvent-tolerant, thermostable, productionAfrican Journal of Biotechnology Vol. 12(21), pp. 3341-335

An Educational Intervention to Reduce Central Venous Catheter Infection Rates

AbstractCentral venous catheters (CVC) are essential in both critical and noncritical care settings. Despite benefits such as the administration of medications, blood products, and parenteral nutrition, CVCs are also associated with infections known as central–line associated blood stream infections (CLABSI). Linked to knowledge deficit and noncompliance in following evidence-based care bundles by nurses, it is important that nurses are empowered through education to provide quality care to reduce CLABSI rates. Thus, a staff education program was developed to answer the practice-focus question: if an organized education program increases the knowledge of medical-surgical nurses on central line care and management procedures for reducing CLABSI. The project was guided by Rogers’ theory of diffusion, adult learning theory, and the John Hopkins evidence-base practice model. Following a literature review to identify current, best practices for managing CVCs, the staff education program was implemented on the target nursing unit using a 10-item pretest/posttest exam to answer the practice-focused question. With a participant group of 40 staff nurses attending the program, a t test showed a statistically significant increase in pretest mean score from 64.19 to a posttest mean of 81.38. The program supports the education needs of nurses working with and managing CVCs. The potential for positive social change includes promoting advocacy in nurses who aspire to make a difference in achieving positive patient outcomes. Last, results can also be added to the existing body of knowledge on translating project findings to clinical practice

Pharmacological Assessment of the Medicinal Potential of Acacia mearnsii De Wild.: Antimicrobial and Toxicity Activities

Acacia mearnsii De Wild. (Fabaceae) is a medicinal plant used in the treatment of microbial infections in South Africa without scientific validation of its bioactivity and toxicity. The antimicrobial activity of the crude acetone extract was evaluated by both agar diffusion and macrobroth dilution methods while its cytotoxicity effect was assessed with brine shrimp lethality assay. The study showed that both bacterial and fungal isolates were highly inhibited by the crude extract. The MIC values for the gram-positive bacteria (78.1–312.5) μg/mL, gram-negative bacteria (39.1–625) μg/mL and fungal isolates (625–5000) μg/mL differ significantly. The bacteria were more susceptible than the fungal strains tested. The antibiosis determination showed that the extract was more (75%) bactericidal than bacteriostatic (25%) and more fungicidal (66.67%) than fungistatic (33.33%). The cytotoxic activity of the extract was observed between 31.25 μg/mL and 500 μg/mL and the LC50 value (112.36 μg/mL) indicates that the extract was nontoxic in the brine shrimp lethality assay (LC50 > 100 μg/mL). These results support the use of A. mearnsii in traditional medicine for treatment of microbial infections. The extract exhibiting significant broad spectrum antimicrobial activity and nontoxic effects has potential to yield active antimicrobial compounds

Developing HIV-1 Protease inhibitors through stereospecific reactions in protein crystals

Protease inhibitors are key components in the chemotherapy of HIV infection. However, the appearance of viral mutants routinely compromises their clinical efficacy, creating a constant need for new and more potent inhibitors. Recently, a new class of epoxide-based inhibitors of HIV-1 protease was investigated and the configuration of the epoxide carbons was demonstrated to play a crucial role in determining the binding affinity. Here we report the comparison between three crystal structures at near-atomic resolution of HIV-1 protease in complex with the epoxide-based inhibitor, revealing an in-situ epoxide ring opening triggered by a pH change in the mother solution of the crystal. Increased pH in the crystal allows a stereospecific nucleophile attack of an ammonia molecule onto an epoxide carbon, with formation of a new inhibitor containing amino-alcohol functions. The described experiments open a pathway for the development of new stereospecific protease inhibitors from a reactive lead compound