Aims: This study aimed to screen extracellular lipase-producing endophytic fungi isolated from Handroanthus impetiginosus (H. impetiginosus).
Study Design: Endophytic fungi were isolated and screened for extracellular lipase production. The best strains obtained were tested for lipase production, via submerged fermentation, using two different carbon sources.
Place and Duration of Study: Institute of Chemistry, Federal University of Alfenas, between June 2016 and December 2017.
Methodology: Healthy and mature leaves were collected from H. impetiginosus in Alfenas/Minas Gerais, Brazil. Endophytic fungi were isolated from leaves by following standard microbiological methods. All isolated fungi (122) were used in the screening for potential lipase production. Submerged fermentation cultivations, using two different carbon sources, were carried out based on the previous screening results obtained. The best lipase-producing endophytic fungus was identified using molecular biology techniques. The produced lipase by submerged fermentation was purified by organic solvent precipitation and characterized by SDS-PAGE analysis.
Results: A total of 122 isolates of endophytic fungi were obtained. Two isolated fungi showed high lipase activity in the plate screening and were chosen for submerged fermentation cultivations using glucose and cottonseed oil as carbon sources. A maximum lipase activity of 5.9 U/mL was obtained for one strain after 48 h of fermentation for the culture medium using cottonseed oil as a carbon source. This strain was genetically identified as Preussia africana. A single protein band with an apparent molecular mass of 64 kDa was detected by SDS-PAGE analysis after lipase purification (purification factor of 18.5).
Conclusion: A potential microorganism, able to produce an extracellular lipase in submerged fermentation, was isolated from H. impetiginosus. To date, this is the first report of extracellular lipase production by Preussia africana. The potential for this new lipase should be evaluated through a full characterization of these lipase properties in further studies.
Toxicity of Local and Industrial Refined Diesel on Nitrobacter Species a Key Environmental Pollution Bio-marker
Aim: Hydrocarbon toxicological effect on nitrogen fixing bacterium Nitrobacter sp. is of prime importance as it affects the nitrification process which negatively and adversely affects aquatic flora. In view of the significance of this process, the toxicity of local and industrial refined diesel on a key environmental pollution bio-marker, Nitrobacter was investigated.
Study Design: Semi-static ecotoxicological bioassay was used to study the effect of varying concentrations of toxicants local and industrial refined diesel on aquatic bacterium Nitrobacter sp.
Place and Duration of Study: Sample: marine water samples were collected from bonny sea, bonny, freshwater from a stream in MuuBagia in BiaraGokana and brackish water from sand-field in Port Harcourt, Nigeria.
Methodology: Winogradsky medium, nutrient agar, and King agar B base was used for the isolation of bacteria species by spread plate techniques. Standard toxicity procedure was carried out using diesel prepared at different concentrations (%) 0, 3.25, 6.5, 12.5, 25 and, 50; tested with Nitrobacter sp. for 0 h, 4 h, 8 h, 12 h, and 24 h separately for each toxicant. Median lethal concentration (LC50) was employed to compute the toxicity of different concentration to the test organism.
Results: The median lethal concentration (LC50) of the diesel used were calculated mean mortality of the test organism Nitrobacter sp. with industrial diesel in fresh water was (43.85%) >Nitrobacter with industrial diesel using brackish water (30.23%) >Nitrobacter with industrial diesel in marine water was (15.93%). Nitrobacter with locally refined diesel in fresh water (34.76%) >Nitrobacter with locally refined diesel in brackish water (26.81%) >Nitrobacter with locally refined diesel in marine water (29.77%). [Noting that the lower the LC50, the more toxic the toxicant].
Conclusion: The study shows that local refined diesel has more toxic effect in brackish and freshwater than industrial refined diesel whereas in marine water a reverse trend occurs; industrial refined diesel being more toxic than local refined diesel. In view of the sensitive nature of Nitrobacter sp. to slight variation in toxicity quotient and its role in biogeochemical cycle; it could serve as a potential tool for eco-toxicological assay and pollution bio-marker.
Optimization of Bioluminescence of Vibrio fischeri and Assessment of Hg++, Cd++, As++, Zn++, Ag+, Cu++ and Ni++ Ions
Various forms of metallic elements are ubiquitous in the environment. The presence of heavy metals in the environment results from natural causes and human activities. They are necessary and even essential for growth and well-being of living organisms. Meanwhile, at high concentration they pose a particular problem by exhibiting more or less strong toxicity. Unlike other toxicants, these elements are not biodegradable. Therefore, they accumulate by marine organisms throughout food chain, which represent a potential danger for flora and fauna. Their toxicity on organisms and their impact on the environment were very different. One of the most important part to evaluate environmental pollution is assessment of heavy metals. Therefore, it is important to use a simple and cost effective method to evaluate toxicants. In this regard, a bioluminescence inhibition method has been optimized. This method consisted to optimize the intensity and stability of luminescence emitted by bacteria Vibrio fischeri (V. fischeri) strain NRRL-B-11177. Toxic effects of Cd++, Zn++, As++, Ag+, Ni++, Cu++ and Hg++ ions have been determined using the method. Results showed aeration (900 ml/min) and agitation (250 rpm) were essential to V. fischeri to emit light. Hg++ ion was the most toxic compared to other tested ions with EC50 value of 0.008 ± 0.001 mg/l. Thus, this method is simple, rapid, sensitive and cost effective, could be used to assess a considerable amount of samples.
Edible termite (Macrotermes nigeriensis), a protein-rich insect is a good source of micro and macronutrients. Quality and acceptability of biscuits produced from wheat-termite flour were evaluated. Wheat flour was enriched with edible termite to produce biscuits with varying amount of termite (100:00, 95:05, 90:10, 85:15 and 80:20). Biscuits were evaluated for chemical composition, physical characteristics and the sensory attributes. The wheat-termite biscuits showed significant difference in their moisture (3.50 – 5.01%), ash (0.72 – 3.32%), fibre (0.74 – 3.35%), fat (0.23 – 5.07%), protein (9.80 – 17.07%) carbohydrate (85.48 – 68.35%) and energy (791 – 719%) contents. The results of the nutrient analysis showed that most of the values increased with the increase in the level of edible termite inclusion. However, the carbohydrate and energy values decreased with the level of inclusion of termite flour. The result of the physical characteristics showed that the diameter increased (5.39 – 5.72 cm) as the thickness decreased (0.63 – 0.52 cm). The spread ratio of the biscuit increased, ranging from 8.55 – 11.00. The break strength of the biscuit reduced with an increase in the level of termite flour inclusion, ranged from 283 – 259 g. The weight also increased from 12.58 – 16.90 g. The result also showed that 5% termite biscuit compared favourably with the control regarding aroma, colour and overall acceptability, it was the most generally accepted sample with the increased level of termite, followed by the sample with 20% termite inclusion. The study has revealed edible termite is an excellent source of nutrients necessary for combating protein-energy-malnutrition rampant in our world today.
Background: Alteration of redox status is a fundamental process in the manifestation of many diseases including malaria. Studies have demonstrated that peptides of the renin-angiotensin-aldosterone system (RAAS), such as Angiotensin Converting Enzyme and Angiotensin II, play a significant role in the pathogenesis of malaria infection by inducing the generation of reactive oxygen species. The present study was aimed at determining the redox status of Plasmodium berghei-infected mice treated with captopril, an angiotensin-converting enzyme inhibitor.
Methodology: Five groups of eight mice each, categorised as control (not infected with P. berghei, not treated), malaria control (P. berghei-infected, not treated), Standard control (P. berghei-infected, treated with 0.03 mg/kg of standard drug, Lonart (Arthemeter 20 mg + Lumefantrine 120 mg), captopril low dose (P. berghei-infected, treated with 0.03 mg/kg captopril) and captopril high dose (P. berghei-infected, treated at with 0.09mg/kg captopril). The mice were treated for 14 days and were sacrificed on the 15th day. Blood samples were collected to determine the levels of reduced glutathione, malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD) and total protein.
Results: Infection with P. berghei significantly (p<0.05) increased MDA, while CAT and SOD levels decreased significantly (p<0.05) compared to mice in the control group. However, MDA levels of mice treated with the standard drug (Artemether 20 mg, Lumefantrine 120 mg), 0.03 and 0.09 mg/kg captopril reduced significantly (p<0.05), while CAT and SOD levels significantly (p<0.05) increased when compared to the malaria control mice. Total protein and reduced glutathione were found to be significantly (p<0.05) high in the malaria control group, whereas a decreased was observed in mice treated with the standard drug and 0.03 mg/kg captopril. Treatment of mice with 0.09 mg/kg captopril significantly increased total protein compared to mice in 0.03 mg/kg captopril group and other groups.
Conclusion: In conclusion, this study has demonstrated that captopril at a low dose can effectively decrease oxidative stress.