Isolation, Characterization and Biodegradation Assay of Glyphosate Utilizing Bacteria from Exposed Rice Farm

Two bacterial species capable of utilizing glyphosate were isolated from the long term glyphosate exposed rice farm and tested for their abilities to utilize glyphosate at different concentrations. The two bacterial isolates were identified by standard bacteriological methods as Pseudomonas sp and Bacillus subtilis using their morphological, biochemical and growth characteristics. The utilization of glyphosate by the isolates was studied by monitoring their biomass production in basal medium containing glyphosate as phosphorus source at 660nm wavelength using the spectrophotometer. The growth of the isolates in the medium with inorganic phosphate as phosphorus source and the effect of different concentrations of glyphosate on the growth and utilization of glyphosate were also studied by assessing the turbidity in the medium at 660nm wavelength. The isolates showed a significant growth in the basal medium containing glyphosate as phosphorus source (P<0.05). Nevertheless, the test organisms showed a better growth rate in the medium with inorganic phosphate as phosphorus source. The effect of different concentrations showed that Pseudomonas sp grew significantly at concentrations of 7.2 mg/ml to 40 mg/ml while B. subtilis showed a reduction in growth with corresponding increase in glyphosate concentration. The results of this study nonetheless underscored the efficacy of the test bacterial isolates in glyphosate utilization, hence their potential as candidates for bioremediation of glyphosate contaminated farmland in poor resource settings. Keywords: Glyphosate herbicide, Utilization pattern, Pseudomonas sp., Bacillus subtilis

LARVICIDAL ACTIVITY OF Picralima nitida, AN ENVIRONMENTAL APPROACH IN MALARIA VECTOR CONTROL

Abstract Insecticide resistance and high incidence of malaria prompt the search for alternative strategies for malaria vector control. This study evaluated the larvicidal efficacy of Picralima nitida on 3rd and early 4th instar larvae of Anopheles gambiae. Laboratory Reared Larvae of Anopheles gambiae were exposed to varying concentrations of the Picralima nitida extracts ranging from 0.5 to 5.0mg/ml, according to WHO Bioassay Methods for susceptibility. Probit analysis using SPSS version 16.0, at (P<0.05) gave LC 50 and LC 95 values of 3.141mg/ml and 42.154mg/ml, 0.352mg/ml and 4.730mg/ml and 0.164mg/ml and 2.201mg/ml for aqueous leaf extracts at 24, 48 and 72h. LC 50 values for methanolic leaf extract were 48.383mg/ml, 15.817mg/ml and 0.333mg/ml at 24h, 48h and 72 h. Methanolic seed extract gave LC 50 value of 0.87mg/ml, 0.21mg/ml and 0.15mg/ml at 24, 48 and 72 h and an LC 95 value of 0.739mg/ml, 0.182mg/ml and 0.124mg/ml at same time interval. The 24 h Relative Potency estimate revealed that aqueous leaf extract had 5.479 times the potency of aqueous seed, while the methanolic seed extract had 269.763 times the potency of the methanolic leaf extracts. The potential use of the methanolic seed and aqueous leaf extracts of P. nitida as an eco-friendly alternative in malaria vector larviciding is demonstrated

Pulp Extracts of Picralima nitida: a Larvicidal Agent in Malaria Vector Control

The methanolic and aqueous pulp extracts of Picralima nitida as an eco-friendly alternative in malaria vector control were investigated. The sample yielded a 3.93% extract with methanol and 0.89% with aqueous. The phytochemicals constitutes of crude methanolic and aqueous extracts of P. nitida pulp include the alkaloids, cardiac glycosides, saponins, tannins, flavonoids, terpenes and steroids. Laboratory reared larvae of Anopheles gambiae 4th instar were exposed to varying concentrations of the P. nitida pulp extracts ranging from 0.5 to 5.0mg/ml, according to WHO Bioassay Methods for susceptibility. Probit analysis using statistical package for social sciences version 16.0, at (P<0.05) gave time dependent LC50 and LC95 values of 4.979 mg/ml and 18.541mg/ml, 4.299 mg/ml and 16.008 mg/ml and 2.792 mg/ml and 10.397 mg/ml for aqueous pulp extracts at 24, 48 and 72 hours while methanolic extract values were 12.285 and 96.993 mg/ml, 9.700 and 76.584 mg/ml and 6.490 and 51.236 mg/ml at 24h, 48h and 72 h respectively. The Relative Potency estimate revealed that methanolic extract has 1.525, 1.554 and 1.880 times the potency of aqueous extract at 24 h, 48 h and 72 h respectively. Keywords: Picralima nitida, Eco-friendly, Insecticides, Resistance, Larvicidal

An Investigation of the Lethality of Picralima Nitida, Family Apocynaceae in Malaria Vector Control

Insecticides resistance and the corresponding health and environmental challenges that arises as a result of the use of synthetic chemical based insecticides prompts the search for better alternative control measures which are more effective, specific in action and less toxic. The 4th instar larvae of Anopheles spp, the vector of the deadly plasmodium were evaluated in this research against aqueous and methanolic leaf extracts of the plant Picralima nitida. Results revealed that aqueous leaf extract of the test plant had a mean mortality of 11 at 24hrs exposure and concentration of 5.0mg/ml. 95% mortality was also recorded at 5.0mg/ml after 48hrs exposure. Methanolic leaf extract had a mean mortality of 7.7 at 48hrs exposure time and same concentration of 5.0mg/ml. however, at 72hrs exposure, (concentration 5.0mg/ml), the mean mortality increased to 19.3 (97% mortality). The Median Lethal Time evaluated using probit analysis at 95% Confidence Limit showed the average lethal time of the test organism Anopheles larvae to the methanolic extract to be 55hrs and 29hrs for the aqueous leaf extract. This result hence supports the fact that leaf extracts of P. nitida can be used as a source of eco-friendly alternatives in the control of mosquito vectors, if developed. Keywords: Resistance, Insecticides, Anopheles spp, Eco-friendly, Larvicidin

Razgradnja cijanida u tlu s pomoću pojedinačnih i miješanih kultura bakterija Pseudomonas stutzeri i Bacillus subtilis

The aim of this investigation was to study whether certain bacteria could be used for cyanide degradation in soil. The bacteria Pseudomonas stutzeri and Bacillus subtilis were selected based on their good growth in a minimal medium containing 0.8 mg mL-1 potassium cyanide (KCN). In this study we tested their ability to reduce cyanide levels in a medium containing 1.5 mg mL-1 of KCN. Although both microorganisms reduced cyanide levels, Pseudomonas stutzeri was the more effective test organism. Later on, the selected cultures were grown, diluted and their various cell concentrations were used individually and in combination to test their ability of cyanide degradation in soil samples collected around a cassava processing mill. Bacillus subtilis caused degradation of soil cyanide from 0.218 mg g-1 soil immediately with an inoculum concentration of 0.1 (OD600nm) to 0.072 mg g-1 soil after 10 days with an inoculum concentration of 0.6 (OD600nm) implying a 66.9 % reduction. Pseudomonas stutzeri cell concentration of 0.1 (OD600nm) decreased soil cyanide from 0.218 mg g-1 soil initially to 0.061 mg g-1 soil after 10 days with an inoculum concentration of 0.6 (OD600nm) (72 % reduction). The mixed culture of the two bacteria produced the best degradation of soil cyanide from 0.218 mg g-1 soil sample with a combined inoculum concentration of 0.1 (OD600nm) initially to 0.025 mg g-1 soil with a combined inoculum concentration of 0.6 (OD600nm) after 10 days incubation resulting in an 88.5 % degradation of soil cyanide. The analysed bacteria displayed high cyanide degradation potential and may be useful for efficient decontamination of cyanide contaminated sites.Bakterije Pseudomonas stutzeri i Bacillus subtilis odabrane su na temelju zamjetnog rasta u minimalnom mediju s 0,8 mg mL-1 kalijeva cijanida (KCN). Tijekom ovog istraživanja ispitivana je njihova sposobnost reduciranja razina cijanida u mediju s 1,5 mg mL-1 KCN. Iako su obje bakterije smanjile koncentraciju cijanida, Pseudomonas stutzeri bila je učinkovitija. Kasnije, odabrane kulture su uzgojene, razrijeđene i u različitim koncentracijama korištene pojedinačno ili u mješavini za ispitivanje njihove učinkovitosti pri razgradnji cijanida u uzorcima tla prikupljenim u blizini mlina za preradu manioke. Bacillus subtilis je uzrokovala razgradnju cijanida od 0,218 mg g-1 na početku pri koncentraciji inokuluma od 0,1 (OD600nm) do 0,072 mg g-1 tla nakon deset dana pri koncentraciji od 0,6 (OD600nm), što je smanjenje od 66,9 %. Stanična koncentracija Pseudomonas stutzeri od 0,1 (OD600nm) smanjila je razinu cijanida u tlu s 0,218 mg g-1 na početku do 0,061 mg g-1 nakon deset dana pri koncentraciji od 0,6 (OD600nm), što je smanjenje od 72 %. Mješavina dviju bakterija dala je najbolju razgradnju; od 0,218 mg g-1 pri miješanoj koncentraciji inokuluma od 0,1 (OD600nm) na početku do 0,025 mg g-1 tla nakon 10 dana pri 0,6 (OD600nm), što je rezultiralo smanjenjem cijanida od 88,5 %. Analizirane bakterije pokazale su visoki potencijal za razgradnju cijanida i mogle bi biti učinkovite za dekontaminaciju cijanidom zagađenih lokacija

ISOLATION, CHARACTERIZATION AND BIODEGRADATION ASSAY OF GLYPHOSATE UTILIZING BACTERIA FROM EXPOSED RICE FARM

Two bacterial IJSER species capable of utilizing glyphosate were isolated from the long term glyphosate exposed rice farm and tested for their abilities to utilize glyphosate at different concentrations. The two bacterial isolates were identified by standard bacteriological methods as Pseudomonas sp and Bacillus subtilis using their morphological, biochemical and growth characteristics. The utilization of glyphosate by the isolates was studied by monitoring their biomass production in basal medium containing glyphosate as phosphorus source at 660nm wavelength using the spectrophotometer. The growth of the isolates in the medium with inorganic phosphate as phosphorus source and the effect of different concentrations of glyphosate on the growth and utilization of glyphosate were also studied by assessing the turbidity in the medium at 660nm wavelength. The isolates showed a significant growth in the basal medium containing glyphosate as phosphorus source (P<0.05). Nevertheless, the test organisms showed a better growth rate in the medium with inorganic phosphate as phosphorus source. The effect of different concentrations showed that Pseudomonas sp grew significantly at concentrations of 7.2 mg/ml to 40 mg/ml while B. subtilis showed a reduction in growth with corresponding increase in glyphosate concentration. The results of this study nonetheless underscored the efficacy of the test bacterial isolates in glyphosate utilization, hence their potential as candidates for bioremediation of glyphosate contaminated farmland in poor resource settings

Anti-biofilm, drug delivery and cytotoxicity properties of dendrimers

Background and purpose: Treatments using antimicrobial agents have faced many difficulties as a result of biofilm formation by pathogenic microorganisms. The biofilm matrix formed by these microorganisms prevents antimicrobial agents from penetrating the interior where they can exact their activity effectively. Additionally, extracellular polymeric molecules associated with biofilm surfaces can absorb antimicrobial compounds, lowering their bioavailability. This problem has resulted in the quest for alternative treatment protocols, and the development of nanomaterials and devices through nanotechnology has recently been on the rise. Research approach: The literature on dendrimers was searched for in databases such as Google Scholar, PubMed, and ScienceDirect. Key results: As a nanomaterial, dendrimers have found useful applications as a drug delivery vehicle for antimicrobial agents against biofilm-mediated infections to circumvent these defense mechanisms. The distinctive properties of dendrimers, such as multi-valency, biocompatibility, high water solubility, non-immunogenicity, and biofilm matrix-/cell membrane fusogenicity (ability to merge with intracellular membrane or other proteins), significantly increase the efficacy of antimicrobial agents and reduce the likelihood of recurring infections. Conclusion: This review outlines the current state of dendrimer carriers for biofilm treatments, provides examples of their real-world uses, and examines potential drawbacks

A meta-analysis on the prevalence of resistance of Staphylococcus aureus to different antibiotics in Nigeria

Abstract Background Rapid emergence of multidrug resistant Staphylococcus aureus has resulted to difficulty in treatment of infections caused by such strains. The aim of this meta-analysis study was to determine the pooled prevalence of resistance of S. aureus to different antibiotics in Nigeria. Methods Literature search for studies was done using Google scholar, PubMed, Science direct, and African Journal Online. The prevalence of S. aureus resistance to different antibiotics was evaluated using the meta-analysis proportion command in MedCalc software version 20.0 adopting a rand effect model. I2 statistic and Egger test in MedCalc was used to evaluate the heterogeneity and the presence of publication bias among studies respectively. Results A total of 40, 682 studies were retrieved through the database search of which 98 studies met the study inclusion criteria. Prevalence of resistance of S. aureus to different antibiotics ranges from 13 to 82%. Results showed a very high degree of resistance to penicillin G (82% [95% confidence interval (CI) 61%, 0.96%]), cloxacillin (77% [95% CI 64%, 88%]), amoxacillin (74% [95% CI 66%, 81%]), cefuroxime (69% [95% CI 51%, 85%]), ampicillin (68% [95% CI 53%, 81%]). Moderately resistance to erythromycin (47% [95% CI 40%, 53%]), chloramphenicol (47% [95% CI 37%, 56%]), methicillin (46% [95% CI 37%, 56%]), ofloxacin (24% [95% CI 18%, 31%]) and rifampicin 24% [95% CI 6%, 48%]). Low resistance was observed in vancomycin 13% (95% CI 7%, 21%). For each individual meta-analysis, high heterogeneity was observed with I2 range (79.36–98.60%) at p-values ≤ 0.01). Egger’s tests for regression intercept in funnel plots indicated no evidence of publication bias. Conclusion This meta-analysis study established that S. aureus in Nigeria has developed resistance to commonly used antibiotics such as the beta-lactam class antibiotics, sulphonamides, tetracyclines, chloramphenicol, and vancomycin. Hence it is imperative to develop programs to promote rational use of antimicrobial agents, infection prevention and control to reduce the incidence of antimicrobial resistance

Additional file 12 of A meta-analysis on the prevalence of resistance of Staphylococcus aureus to different antibiotics in Nigeria

Additional file 12: S12. Forest plot of the prevalence of S. aureus resistance to erythromyci

Additional file 5 of A meta-analysis on the prevalence of resistance of Staphylococcus aureus to different antibiotics in Nigeria

Additional file 5: S5. Forest plot of the prevalence of S. aureus resistance to augmenti