The goal of this study was to determine whether mutation of the Mn-binding site of wild-type reco... more The goal of this study was to determine whether mutation of the Mn-binding site of wild-type recombinant Phlebia radiata manganese peroxidase 3 affected the pH-dependence kinetic parameters. pH range investigated was 2.5-12.0. The catalytic efficiency of the mutant enzymes at high and low pH in comparison to the wild-type was investigated using standard rPr-MnP3 protocol. Wild-type recombinant Phlebia radiata MnP3 enzyme showed optimal activity with Mn (II) as substrate at pH 5.0 and remained moderately active (approximately 40%) in the pH range of 6.0-9.0. The rPr-MnP3 mutants' maximum activity ranged between 5.5 and 8.0. Wild-type and mutants rPr-MnP3 enzymes exhibited a similar pH profile with optimum pH of 3.0 for ABTS oxidation. Mutation has severely decreased the catalytic efficiency for Mn (II) oxidation at pH 5.0. The rPr-MnP3 enzymes showed enhanced affinity for Mn (II) at alkaline pH and a more alkaline range for catalysis than ever reported for any Manganese Peroxidase. This study reveals that at higher pH, rPr-MnP3 can function with alternative ligands in the Mn (II) site and does not have an absolutely obligate requirement for an all carboxylate ligand set. These results further strongly confirm that Mn 2+ binding site is the only productive catalytic site for Mn (II) oxidation.
American Journal of Environmental Protection, 2016
Epiphytic lichen (Parmelia carperata) and moss (Polytrichum juniperinum, Calymperes erosum and Ra... more Epiphytic lichen (Parmelia carperata) and moss (Polytrichum juniperinum, Calymperes erosum and Racopilum africanum) samples were used as bioindicators and bioaccumulators of atmospheric heavy metals deposition in oil–producing host communities of Eket and Ibeno Local Government Areas of Akwa Ibom State – Nigeria. Sampling of lichen and moss species that are found to grow extensively and abundantly on the stems and branches of several plants was performed during September 2014 at 25 sampling location sevenly distributed over the two oil–producing host communities studied. Unwashed, oven dried and homogenized powdered lichen and moss samples were mineralized using wet digestion with 3:1 mixture of concentrated nitric acid and perchloric acid in Teflon beakers on a Gerhardt digestion hot plate. The concentrations of heavy metals and/or trace elements were determined by atomic absorption spectrometry (AAS) equipped with flame and/or graphite furnace systems. The concentration of heavy m...
Cola millenii is a medicinal plant believed to have many agents acting in different ways for the ... more Cola millenii is a medicinal plant believed to have many agents acting in different ways for the health benefits of humans. This study investigated the acute toxicity, phytochemicals content and the effects on haematological indices, lipid profile, and biomarkers of cardiac and prostate dysfunction. Twenty eight (28) adult male Wistar albino rats weighing 151-195 g were used in four groups of six animals. Group 1 (control) received 0.34 ml of 20% Tween® 80 as placebo, groups 2, 3 and 4, received intraperitoneal injection of 150, 300 and 450 mg/kg body weight of the extract respectively for seven days. The result indicates the presence of alkaloids, terpenes, saponins and cardiac glycosides. Intraperitoneal LD50 was 2645.75 mg/kg body weight. There was significant (p
Nigerian journal of physiological sciences : official publication of the Physiological Society of Nigeria, 2020
Vitamin E has been used as antioxidant and in the treatment of various ailments due to oxidative ... more Vitamin E has been used as antioxidant and in the treatment of various ailments due to oxidative stress. The cardio-protective effect of vitamin E in dexamethasone induced oxidative stress was studied. Forty Wistar rats were randomly assigned to four groups of 10 rats each. Control group received normal rat chow. Oxidative stress was induced using 30µg/kg body weight of dexamethasone (DEX) intraperitonealy in DEX+Vit E and DEX only groups while Vitamin E was administered orally at a dose of 300 IU/kg to Vitamin E only group and DEX+Vit E group daily for 14 days. All animals were fed ad libitum and had free access to water. Blood samples were obtained by cardiac puncture for biochemical analyses while heart and kidney were processed for histological staining.  The result shows a significant (p<0.05) decrease in serum nitric oxide, bilirubin and superoxide dismutase concentration in DEX-only group which was elevated following vitamin E treatment. The angiotensin converting enzyme a...
American Journal of Environmental Protection, 2016
Advances in the development of petroleum resources has contributed enormously to the global energ... more Advances in the development of petroleum resources has contributed enormously to the global energy demand and economic development over the past decades, however, it has left profound negative impacts on the natural environment and adverse human health effects in most oil-producing host communities around the world. Apart from the loss of petroleum-derived revenue to corruption and ineffective government's petroleum development policies, the Niger Delta region has experienced a wide range of environmental pollution, degradation, human health risks and socio-economic problems associated with petroleum exploration, development and production. Over the years, several environmental laws have been institutionalized to regulate the petroleum sector in Nigeria. The Nigerian government and other African countries have played tremendous roles in the emergence of international environmental law that regulate the establishment of environmental institutions and legislations as well as strat...
This study investigated the steady-state kinetics of engineered wild-type and manganese (II) bind... more This study investigated the steady-state kinetics of engineered wild-type and manganese (II) binding site mutants of recombinant Phlebia radiata manganese peroxidase 3(rPr-MnP3). The effect (activation or inhibition) of some metal ions (Co2+, Zn2+ Cu2+ and Na+) on the activity of rPr-MnP3 enzymes was also studied. The results obtained showed that the rPr-MnP3 mutants in which the metal binding functionality has been largely lost have been created. Na+ (mono-valent ion) and Co2+showed similar characteristics by exhibiting stimulatory effects on the activity of wild-type rPr-MnP3. However, Cu2+ and Zn2+ had mixed inhibitory effects on wild-type and mutants (E40H, E44H, E40H/E44H). It was observed that Cu2+ was by far the strongest inhibitor of engineered rPr-MnP3 enzymes while Co2+ exhibited a non-competitive inhibitory effect on the double mutant (E40H/E44H) and D186H activities. In addition, Zn2+ and Cu2+also had non-competitive inhibitory effect on D186H mutant enzyme activity. The...
Objectives: Rothmannia hispida (R. hispida) is used in West African traditional medicine for the ... more Objectives: Rothmannia hispida (R. hispida) is used in West African traditional medicine for the treatment of various ailments such as fever, dysentery, skin infections, abdominal pain and diabetes mellitus. To elucidate the pharmacological basis of the antidiabetic efficacy of this plant drug, the effect of R. hispida on insulin and alpha amylase levels were examined in alloxan-induced diabetic rats. Method: Diabetic rats were treated with leaf extract of R. hipida at dose levels of 250mg/kg and 500mg/kg respectively. The concentration of insulin in serum samples was estimated using Enzyme-Linked Immunoabsorbent Assay (ELISA) method using insulin kit (Syntron Bioresearch, USA), alpha amylase levels were estimated using routine biochemical procedures. Results: Treatment of alloxan diabetic rats with leaf extract of R. hipida significantly (p<0.001) reduced hyperglycaemia, significantly (p<0.001) attenuated alloxan-induced hypoinsulinaemia and significantly (p<0.01) increase...
Gongronema latifolium (GL) has been used traditionally in the management of various ailments. The... more Gongronema latifolium (GL) has been used traditionally in the management of various ailments. The effects of GL on some haematological and biochemical parameters in fructose-induced hyperglycaemia were studied. Forty rats were randomly assigned to four groups of 10 rats each. Control was received normal rat chow, fructose + G. latifolium group was received 66% D-fructose mixed with 34% chow and crude leaf extract of GL daily. Fructose only group was received 66% D-fructose and the fourth group was received GL extract only respectively for 30 days. All animals were fed ad libitum and had free access to water. Oral blood glucose tolerance test was determined using 2 g/Kg in all groups of rats and blood samples were obtained by cardiac puncture for haematological and biochemical analyses. The blood glucose level was significantly raised in fructose-fed only group (140.6 ± 2.9 mg/dl) when compared to GL + fructose group (110.3 ±5.8 mg/dl) and control (88.1 ± 3.6 mg/dl). There was observ...
Background. Manganese peroxidases (MnP) and lignin peroxidases (LiP) are haem-including fungal se... more Background. Manganese peroxidases (MnP) and lignin peroxidases (LiP) are haem-including fungal secreted class-II peroxidases, which are interesting oxidoreductases in protein engineering aimed at design of biocatalysts for lignin and lignocellulose conversion, dye compound degradation, activation of aromatic compounds, and biofuel production. Objective. Recombinant short-type MnP (Pr-MnP3) of the white rot fungus Phlebia radiata, and its manganese-binding site (E40, E44, D186) directed variants were produced and characterized. To allow catalytic applications, enzymatic bleaching of Reactive Blue 5 and conversion of lignin-like compounds by engineered class-II peroxidases were explored. Method. Pr-MnP3 and its variants were expressed in Escherichia coli. The resultant body proteins were lysed, purified and refolded into haem-including enzymes in 6-7% protein recovery, and examined spectroscopically and kinetically. Results. Successful production of active enzymes was attained, with spectral characteristics of high-spin class-II peroxidases. Recombinant Pr-MnP3 demonstrated high affinity to Mn 2+ , which was noticeably affected by single (D186H/N) and double (E40H+E44H) mutations. Without addition of Mn 2+ , Pr-MnP3 was able to oxidize ABTS and decolorize Reactive Blue 5. Pc-LiPH8, its Trp-radical site variants, and engineered CiP-LiP demonstrated conversion of veratryl alcohol and dimeric non-phenolic lignin-model compounds (arylglycerol-β-aryl ethers) with production of veratraldehyde, which is evidence for cation radical formation with subsequent Cα-Cβ cleavage. Pc-LiPH8 and CiP variants were able to effectively oxidize and convert the phenolic dimer (guaiacylglycerol-β-guaiacyl ether). Conclusion. Our results demonstrate suitability of engineered MnP and LiP peroxidases for dye-decolorizing, and efficiency of LiP and its variants for activation and degradation of phenolic and non-phenolic lignin-like aryl ether-linked compounds.
I am first all most grateful to the Almighty God who made this training opportunity possible thro... more I am first all most grateful to the Almighty God who made this training opportunity possible through Akwa Ibom State University of Technology staff training programme. All my successes, achievements and sustenance I received from you. I am grateful to my supervisor Professor Andrew T. Smith for giving me the opportunity to work in his laboratory. His guidance, suggestions and ideas were invaluable and enhanced the successful completion of this study. He taught me independence, patience and endurance, which have ensured my success. It has been a great opportunity to work in a very stimulating and multidisciplinary scientific environment. The scientific competence and encouragement made this training a rich and fruitful time for me. I am thankful to my co-supervisor Dr. Neil Crickmore for always being there for me whenever I needed help or advice. The author is extremely thankful to Dr. Wendy Doyle for her wonderful role throughout the period of my PhD studies. I am particularly humbled by her selfless and sacrificial support. I will not forget in a hurry Wendy's painstaking guidance and involvement particularly during the writing of this thesis. In the absence of my supervisor, you gave me hope. Your advice was invaluable. I am grateful to Prof. Mike Wallis for his advice and guidance in the writing of thesis. Present and former members of Lab. 13 and particularly Andy's group are thanked Maria, Khasim, Sarah, Elodie and Falah deserve many thanks for the various supports I received from them during my study. My friends both at home and abroad I wish to thank for just being there. Kevin, Daniel, Udorohs, Oworens, Akpanabiatu have shared memorable moments and experiences with me. Your encouragement and prayers have been immense. Thanks also to all those I do not mention but do not forget. I am much indebted to my family, wife, children, my brothers, sisters, and other relations for prayers and support. My in-laws are highly acknowledged for all the assistance and support given to my family during these years of my absence from home. Of particular mention are the patience, sacrifice, endurance, encouragement and understanding shown by my wife, Mboso and children, Unwana, Ifiok, Inyene and Uduak. iv-It always seems impossible until it's done‖. v Expression and characterisation of a Novel Manganese Peroxidase from Phlebia radiata.
Influe inac (E40H/ Department of epartment of Thermal ina presence a temperature determined of rP... more Influe inac (E40H/ Department of epartment of Thermal ina presence a temperature determined of rPr-MnP3 the half-life Ethylenedia by the deca 0.002 min-1 protective e was observ inactivation found to be that rPr-Mn
ABSTRACT Some foods interact with drugs, thereby increasing or decreasing the effectiveness of th... more ABSTRACT Some foods interact with drugs, thereby increasing or decreasing the effectiveness of the drugs. The effect of ten vegetables on the pharmacokinetics of Chloroquine (CQ) and Dihydroartemisinin (DHA), used as antimalarial, was investigated. Extracts of Telfairia occidentalis, Vernonia amygdalina, Gnetum africana, Heinsia crinata, Lasianthera africana, Talinum triangulare, Corchorus olitorius, Ocimum gratisimum, Gongronema latifolium and Amaranthus hybridus (200mg/kg each)were orally co-administered with CQ (10mg/kg) and DHA (2mg/kg), respectively. Concentrations of CQ and DHA were analyzed using UV spectrophotometry in blood collected by cardiac puncture from the rats at 0.5, 1.0, 2.0, 5.0 and 8.0 hrs. Absorption rate (Ka), elimination rate (Ke), area under the curve (AUC), maximum concentration (Cmax), peak time (tmax), half-life (t 1/2), Clearance (Cl), Volume of distribution (Vd) and Bioavailability (F) of the drugs were calculated. Many of the plants affected the pharmacokinetics of the drugs. Telfairia occidentalis altered all the parameters of CQ. It increased Ka, Ke and AUC by 25, 831 and 58%, respectively; reduced t 1/2 , tmax, Cl, Vd and F by 91, 64, 37, 94, 96%, respectively. Similarly, the plant increased Ka (by 14%), AUC (58%); reduced t 1/2 (41%)and Vd (by 67%) of DHA. Talinum triangularealtered all the parameters of CQ. It increased Ka, Ke and AUC by 25, 831 and 58%, respectively; reduced t 1/2 (by 91%), tmax (64%), Cl (37%), Vd(94%) and F (96%). It could be concluded from the results that some of the vegetables, especially Telfairia occidentalis and Talinum triangulare, can affect the efficacy of Chloroquine and Dihydroartemisinin. Please cite this article in press as DrOlorunfemi A. Eseyin et.al. Evaluation of the effect of some common Nigerian vegetables on the Pharmacokinetics of Chloroquine and Dihydroartemisinin in rat.
Manganese peroxidases (MnPs) are interesting enzymes in protein engineering, aimed at maximizing ... more Manganese peroxidases (MnPs) are interesting enzymes in protein engineering, aimed at maximizing industrial bioprocesses such as lignin degradation and biofuel production. cDNA of the secreted shorttype of MnP from Phlebia radiata (Pr-MnP3) has been successfully engineered and amplified by polymerase chain reaction (PCR). Five mutant genes (E40H, E44H, E40H/E44H, D186H and D186N) of recombinant Phlebia radiata MnP3 (rPr-MnP3) were generated. The wild-type and the mutant genes were expressed in Escherichia coli (W3110 strain) and the resultant body proteins were lysed, purified and refolded into active enzymes. 6%-7% recovery of pure and fully active rPr-MnP3 for wild-type and mutants were obtained and the availability of rPr-MnP3 enzymes will greatly facilitate its structure-function relationships studies. rPr-MnP3 mass was characterised using SDS-PAGE and MALDI-TOF mass spectrometry. Molecular weight of both the wild-type and mutant rPr-MnP3 enzymes was approximately 36 kDa. This paper describes the spectral characterization of the wild-type and mutant rPr-MnP3 enzymes with very close similarities; substantially high spin haem enzymes. Therefore we report the engineering, cloning, expression, refolding/activation of MnP3 genes and preliminary characterization of the wild-type and mutant Phlebia radiata MnP3 enzymes.
Aframomum melegueta is a popular medicinal plant in Nigeria believed to have many agents acting i... more Aframomum melegueta is a popular medicinal plant in Nigeria believed to have many agents acting in different ways to bring about human health benefits. This study aimed to determine the acute toxicity, identify some phytochemicals known to be present in this plant and the possible effects on lipid profile, haematological indices and biomarker of prostate and cardiac dysfunction. Twenty four Wistar rats (284-326 g) were used in four groups of six animals. Group 1 (control) received normal saline; groups 2, 3 and 4, received intraperitoneal injection of 27.39, 54.77 and 82.16 mg/kg body weight of the extract respectively for 7 days. Haematological and biochemical parameters were measured. Alkaloids, flavonoids, saponins, tannins, cardiac glycosides, terpenoids and steroids were identified in this plant extract. The LD₅₀ was 273.86 mg/kg body weight. Prostate Specific Antigen (PSA) decreased significantly in group 2. Testosterone increased significantly in all the test groups compared to the control. Cardiac troponin I (0 ng/dl) was recorded for the test groups while the control had 1.69 ± 0.12 ng/dl. Lipid profile results showed increase in HDL and decrease in total cholesterol and LDL-cholesterol. Haemoglobin (Hb) and Red Blood Cells count (RBC) decreased significantly in group 4. White Blood Cells count (WBC), Mean Cell Volume (MCV), Mean Cell Haemoglobin (MCH) and Mean Cell Haemoglobin Concentration (MCHC) did not change significantly. Aframomum melegueta seed oil has the potential of ameliorating benign prostatic hyperplasia (BPH) and cardiac dysfunction as indicated by testosterone, PSA, lipid profile and troponin I levels. The LD₅₀ of 273.86 mg/kg body weight is indicative of mild toxicity. The lower than normal Hb, RBC confirms the possibility of toxicity.
Vitamin supplementation in Rauwolfia vomitoria root bark extract administration may interact and ... more Vitamin supplementation in Rauwolfia vomitoria root bark extract administration may interact and impact significantly on hematology of albino Wistar rats.
The goal of this study was to determine whether mutation of the Mn-binding site of wild-type reco... more The goal of this study was to determine whether mutation of the Mn-binding site of wild-type recombinant Phlebia radiata manganese peroxidase 3 affected the pH-dependence kinetic parameters. pH range investigated was 2.5-12.0. The catalytic efficiency of the mutant enzymes at high and low pH in comparison to the wild-type was investigated using standard rPr-MnP3 protocol. Wild-type recombinant Phlebia radiata MnP3 enzyme showed optimal activity with Mn (II) as substrate at pH 5.0 and remained moderately active (approximately 40%) in the pH range of 6.0-9.0. The rPr-MnP3 mutants' maximum activity ranged between 5.5 and 8.0. Wild-type and mutants rPr-MnP3 enzymes exhibited a similar pH profile with optimum pH of 3.0 for ABTS oxidation. Mutation has severely decreased the catalytic efficiency for Mn (II) oxidation at pH 5.0. The rPr-MnP3 enzymes showed enhanced affinity for Mn (II) at alkaline pH and a more alkaline range for catalysis than ever reported for any Manganese Peroxidase. This study reveals that at higher pH, rPr-MnP3 can function with alternative ligands in the Mn (II) site and does not have an absolutely obligate requirement for an all carboxylate ligand set. These results further strongly confirm that Mn 2+ binding site is the only productive catalytic site for Mn (II) oxidation.
American Journal of Environmental Protection, 2016
Epiphytic lichen (Parmelia carperata) and moss (Polytrichum juniperinum, Calymperes erosum and Ra... more Epiphytic lichen (Parmelia carperata) and moss (Polytrichum juniperinum, Calymperes erosum and Racopilum africanum) samples were used as bioindicators and bioaccumulators of atmospheric heavy metals deposition in oil–producing host communities of Eket and Ibeno Local Government Areas of Akwa Ibom State – Nigeria. Sampling of lichen and moss species that are found to grow extensively and abundantly on the stems and branches of several plants was performed during September 2014 at 25 sampling location sevenly distributed over the two oil–producing host communities studied. Unwashed, oven dried and homogenized powdered lichen and moss samples were mineralized using wet digestion with 3:1 mixture of concentrated nitric acid and perchloric acid in Teflon beakers on a Gerhardt digestion hot plate. The concentrations of heavy metals and/or trace elements were determined by atomic absorption spectrometry (AAS) equipped with flame and/or graphite furnace systems. The concentration of heavy m...
Cola millenii is a medicinal plant believed to have many agents acting in different ways for the ... more Cola millenii is a medicinal plant believed to have many agents acting in different ways for the health benefits of humans. This study investigated the acute toxicity, phytochemicals content and the effects on haematological indices, lipid profile, and biomarkers of cardiac and prostate dysfunction. Twenty eight (28) adult male Wistar albino rats weighing 151-195 g were used in four groups of six animals. Group 1 (control) received 0.34 ml of 20% Tween® 80 as placebo, groups 2, 3 and 4, received intraperitoneal injection of 150, 300 and 450 mg/kg body weight of the extract respectively for seven days. The result indicates the presence of alkaloids, terpenes, saponins and cardiac glycosides. Intraperitoneal LD50 was 2645.75 mg/kg body weight. There was significant (p
Nigerian journal of physiological sciences : official publication of the Physiological Society of Nigeria, 2020
Vitamin E has been used as antioxidant and in the treatment of various ailments due to oxidative ... more Vitamin E has been used as antioxidant and in the treatment of various ailments due to oxidative stress. The cardio-protective effect of vitamin E in dexamethasone induced oxidative stress was studied. Forty Wistar rats were randomly assigned to four groups of 10 rats each. Control group received normal rat chow. Oxidative stress was induced using 30µg/kg body weight of dexamethasone (DEX) intraperitonealy in DEX+Vit E and DEX only groups while Vitamin E was administered orally at a dose of 300 IU/kg to Vitamin E only group and DEX+Vit E group daily for 14 days. All animals were fed ad libitum and had free access to water. Blood samples were obtained by cardiac puncture for biochemical analyses while heart and kidney were processed for histological staining.  The result shows a significant (p<0.05) decrease in serum nitric oxide, bilirubin and superoxide dismutase concentration in DEX-only group which was elevated following vitamin E treatment. The angiotensin converting enzyme a...
American Journal of Environmental Protection, 2016
Advances in the development of petroleum resources has contributed enormously to the global energ... more Advances in the development of petroleum resources has contributed enormously to the global energy demand and economic development over the past decades, however, it has left profound negative impacts on the natural environment and adverse human health effects in most oil-producing host communities around the world. Apart from the loss of petroleum-derived revenue to corruption and ineffective government's petroleum development policies, the Niger Delta region has experienced a wide range of environmental pollution, degradation, human health risks and socio-economic problems associated with petroleum exploration, development and production. Over the years, several environmental laws have been institutionalized to regulate the petroleum sector in Nigeria. The Nigerian government and other African countries have played tremendous roles in the emergence of international environmental law that regulate the establishment of environmental institutions and legislations as well as strat...
This study investigated the steady-state kinetics of engineered wild-type and manganese (II) bind... more This study investigated the steady-state kinetics of engineered wild-type and manganese (II) binding site mutants of recombinant Phlebia radiata manganese peroxidase 3(rPr-MnP3). The effect (activation or inhibition) of some metal ions (Co2+, Zn2+ Cu2+ and Na+) on the activity of rPr-MnP3 enzymes was also studied. The results obtained showed that the rPr-MnP3 mutants in which the metal binding functionality has been largely lost have been created. Na+ (mono-valent ion) and Co2+showed similar characteristics by exhibiting stimulatory effects on the activity of wild-type rPr-MnP3. However, Cu2+ and Zn2+ had mixed inhibitory effects on wild-type and mutants (E40H, E44H, E40H/E44H). It was observed that Cu2+ was by far the strongest inhibitor of engineered rPr-MnP3 enzymes while Co2+ exhibited a non-competitive inhibitory effect on the double mutant (E40H/E44H) and D186H activities. In addition, Zn2+ and Cu2+also had non-competitive inhibitory effect on D186H mutant enzyme activity. The...
Objectives: Rothmannia hispida (R. hispida) is used in West African traditional medicine for the ... more Objectives: Rothmannia hispida (R. hispida) is used in West African traditional medicine for the treatment of various ailments such as fever, dysentery, skin infections, abdominal pain and diabetes mellitus. To elucidate the pharmacological basis of the antidiabetic efficacy of this plant drug, the effect of R. hispida on insulin and alpha amylase levels were examined in alloxan-induced diabetic rats. Method: Diabetic rats were treated with leaf extract of R. hipida at dose levels of 250mg/kg and 500mg/kg respectively. The concentration of insulin in serum samples was estimated using Enzyme-Linked Immunoabsorbent Assay (ELISA) method using insulin kit (Syntron Bioresearch, USA), alpha amylase levels were estimated using routine biochemical procedures. Results: Treatment of alloxan diabetic rats with leaf extract of R. hipida significantly (p<0.001) reduced hyperglycaemia, significantly (p<0.001) attenuated alloxan-induced hypoinsulinaemia and significantly (p<0.01) increase...
Gongronema latifolium (GL) has been used traditionally in the management of various ailments. The... more Gongronema latifolium (GL) has been used traditionally in the management of various ailments. The effects of GL on some haematological and biochemical parameters in fructose-induced hyperglycaemia were studied. Forty rats were randomly assigned to four groups of 10 rats each. Control was received normal rat chow, fructose + G. latifolium group was received 66% D-fructose mixed with 34% chow and crude leaf extract of GL daily. Fructose only group was received 66% D-fructose and the fourth group was received GL extract only respectively for 30 days. All animals were fed ad libitum and had free access to water. Oral blood glucose tolerance test was determined using 2 g/Kg in all groups of rats and blood samples were obtained by cardiac puncture for haematological and biochemical analyses. The blood glucose level was significantly raised in fructose-fed only group (140.6 ± 2.9 mg/dl) when compared to GL + fructose group (110.3 ±5.8 mg/dl) and control (88.1 ± 3.6 mg/dl). There was observ...
Background. Manganese peroxidases (MnP) and lignin peroxidases (LiP) are haem-including fungal se... more Background. Manganese peroxidases (MnP) and lignin peroxidases (LiP) are haem-including fungal secreted class-II peroxidases, which are interesting oxidoreductases in protein engineering aimed at design of biocatalysts for lignin and lignocellulose conversion, dye compound degradation, activation of aromatic compounds, and biofuel production. Objective. Recombinant short-type MnP (Pr-MnP3) of the white rot fungus Phlebia radiata, and its manganese-binding site (E40, E44, D186) directed variants were produced and characterized. To allow catalytic applications, enzymatic bleaching of Reactive Blue 5 and conversion of lignin-like compounds by engineered class-II peroxidases were explored. Method. Pr-MnP3 and its variants were expressed in Escherichia coli. The resultant body proteins were lysed, purified and refolded into haem-including enzymes in 6-7% protein recovery, and examined spectroscopically and kinetically. Results. Successful production of active enzymes was attained, with spectral characteristics of high-spin class-II peroxidases. Recombinant Pr-MnP3 demonstrated high affinity to Mn 2+ , which was noticeably affected by single (D186H/N) and double (E40H+E44H) mutations. Without addition of Mn 2+ , Pr-MnP3 was able to oxidize ABTS and decolorize Reactive Blue 5. Pc-LiPH8, its Trp-radical site variants, and engineered CiP-LiP demonstrated conversion of veratryl alcohol and dimeric non-phenolic lignin-model compounds (arylglycerol-β-aryl ethers) with production of veratraldehyde, which is evidence for cation radical formation with subsequent Cα-Cβ cleavage. Pc-LiPH8 and CiP variants were able to effectively oxidize and convert the phenolic dimer (guaiacylglycerol-β-guaiacyl ether). Conclusion. Our results demonstrate suitability of engineered MnP and LiP peroxidases for dye-decolorizing, and efficiency of LiP and its variants for activation and degradation of phenolic and non-phenolic lignin-like aryl ether-linked compounds.
I am first all most grateful to the Almighty God who made this training opportunity possible thro... more I am first all most grateful to the Almighty God who made this training opportunity possible through Akwa Ibom State University of Technology staff training programme. All my successes, achievements and sustenance I received from you. I am grateful to my supervisor Professor Andrew T. Smith for giving me the opportunity to work in his laboratory. His guidance, suggestions and ideas were invaluable and enhanced the successful completion of this study. He taught me independence, patience and endurance, which have ensured my success. It has been a great opportunity to work in a very stimulating and multidisciplinary scientific environment. The scientific competence and encouragement made this training a rich and fruitful time for me. I am thankful to my co-supervisor Dr. Neil Crickmore for always being there for me whenever I needed help or advice. The author is extremely thankful to Dr. Wendy Doyle for her wonderful role throughout the period of my PhD studies. I am particularly humbled by her selfless and sacrificial support. I will not forget in a hurry Wendy's painstaking guidance and involvement particularly during the writing of this thesis. In the absence of my supervisor, you gave me hope. Your advice was invaluable. I am grateful to Prof. Mike Wallis for his advice and guidance in the writing of thesis. Present and former members of Lab. 13 and particularly Andy's group are thanked Maria, Khasim, Sarah, Elodie and Falah deserve many thanks for the various supports I received from them during my study. My friends both at home and abroad I wish to thank for just being there. Kevin, Daniel, Udorohs, Oworens, Akpanabiatu have shared memorable moments and experiences with me. Your encouragement and prayers have been immense. Thanks also to all those I do not mention but do not forget. I am much indebted to my family, wife, children, my brothers, sisters, and other relations for prayers and support. My in-laws are highly acknowledged for all the assistance and support given to my family during these years of my absence from home. Of particular mention are the patience, sacrifice, endurance, encouragement and understanding shown by my wife, Mboso and children, Unwana, Ifiok, Inyene and Uduak. iv-It always seems impossible until it's done‖. v Expression and characterisation of a Novel Manganese Peroxidase from Phlebia radiata.
Influe inac (E40H/ Department of epartment of Thermal ina presence a temperature determined of rP... more Influe inac (E40H/ Department of epartment of Thermal ina presence a temperature determined of rPr-MnP3 the half-life Ethylenedia by the deca 0.002 min-1 protective e was observ inactivation found to be that rPr-Mn
ABSTRACT Some foods interact with drugs, thereby increasing or decreasing the effectiveness of th... more ABSTRACT Some foods interact with drugs, thereby increasing or decreasing the effectiveness of the drugs. The effect of ten vegetables on the pharmacokinetics of Chloroquine (CQ) and Dihydroartemisinin (DHA), used as antimalarial, was investigated. Extracts of Telfairia occidentalis, Vernonia amygdalina, Gnetum africana, Heinsia crinata, Lasianthera africana, Talinum triangulare, Corchorus olitorius, Ocimum gratisimum, Gongronema latifolium and Amaranthus hybridus (200mg/kg each)were orally co-administered with CQ (10mg/kg) and DHA (2mg/kg), respectively. Concentrations of CQ and DHA were analyzed using UV spectrophotometry in blood collected by cardiac puncture from the rats at 0.5, 1.0, 2.0, 5.0 and 8.0 hrs. Absorption rate (Ka), elimination rate (Ke), area under the curve (AUC), maximum concentration (Cmax), peak time (tmax), half-life (t 1/2), Clearance (Cl), Volume of distribution (Vd) and Bioavailability (F) of the drugs were calculated. Many of the plants affected the pharmacokinetics of the drugs. Telfairia occidentalis altered all the parameters of CQ. It increased Ka, Ke and AUC by 25, 831 and 58%, respectively; reduced t 1/2 , tmax, Cl, Vd and F by 91, 64, 37, 94, 96%, respectively. Similarly, the plant increased Ka (by 14%), AUC (58%); reduced t 1/2 (41%)and Vd (by 67%) of DHA. Talinum triangularealtered all the parameters of CQ. It increased Ka, Ke and AUC by 25, 831 and 58%, respectively; reduced t 1/2 (by 91%), tmax (64%), Cl (37%), Vd(94%) and F (96%). It could be concluded from the results that some of the vegetables, especially Telfairia occidentalis and Talinum triangulare, can affect the efficacy of Chloroquine and Dihydroartemisinin. Please cite this article in press as DrOlorunfemi A. Eseyin et.al. Evaluation of the effect of some common Nigerian vegetables on the Pharmacokinetics of Chloroquine and Dihydroartemisinin in rat.
Manganese peroxidases (MnPs) are interesting enzymes in protein engineering, aimed at maximizing ... more Manganese peroxidases (MnPs) are interesting enzymes in protein engineering, aimed at maximizing industrial bioprocesses such as lignin degradation and biofuel production. cDNA of the secreted shorttype of MnP from Phlebia radiata (Pr-MnP3) has been successfully engineered and amplified by polymerase chain reaction (PCR). Five mutant genes (E40H, E44H, E40H/E44H, D186H and D186N) of recombinant Phlebia radiata MnP3 (rPr-MnP3) were generated. The wild-type and the mutant genes were expressed in Escherichia coli (W3110 strain) and the resultant body proteins were lysed, purified and refolded into active enzymes. 6%-7% recovery of pure and fully active rPr-MnP3 for wild-type and mutants were obtained and the availability of rPr-MnP3 enzymes will greatly facilitate its structure-function relationships studies. rPr-MnP3 mass was characterised using SDS-PAGE and MALDI-TOF mass spectrometry. Molecular weight of both the wild-type and mutant rPr-MnP3 enzymes was approximately 36 kDa. This paper describes the spectral characterization of the wild-type and mutant rPr-MnP3 enzymes with very close similarities; substantially high spin haem enzymes. Therefore we report the engineering, cloning, expression, refolding/activation of MnP3 genes and preliminary characterization of the wild-type and mutant Phlebia radiata MnP3 enzymes.
Aframomum melegueta is a popular medicinal plant in Nigeria believed to have many agents acting i... more Aframomum melegueta is a popular medicinal plant in Nigeria believed to have many agents acting in different ways to bring about human health benefits. This study aimed to determine the acute toxicity, identify some phytochemicals known to be present in this plant and the possible effects on lipid profile, haematological indices and biomarker of prostate and cardiac dysfunction. Twenty four Wistar rats (284-326 g) were used in four groups of six animals. Group 1 (control) received normal saline; groups 2, 3 and 4, received intraperitoneal injection of 27.39, 54.77 and 82.16 mg/kg body weight of the extract respectively for 7 days. Haematological and biochemical parameters were measured. Alkaloids, flavonoids, saponins, tannins, cardiac glycosides, terpenoids and steroids were identified in this plant extract. The LD₅₀ was 273.86 mg/kg body weight. Prostate Specific Antigen (PSA) decreased significantly in group 2. Testosterone increased significantly in all the test groups compared to the control. Cardiac troponin I (0 ng/dl) was recorded for the test groups while the control had 1.69 ± 0.12 ng/dl. Lipid profile results showed increase in HDL and decrease in total cholesterol and LDL-cholesterol. Haemoglobin (Hb) and Red Blood Cells count (RBC) decreased significantly in group 4. White Blood Cells count (WBC), Mean Cell Volume (MCV), Mean Cell Haemoglobin (MCH) and Mean Cell Haemoglobin Concentration (MCHC) did not change significantly. Aframomum melegueta seed oil has the potential of ameliorating benign prostatic hyperplasia (BPH) and cardiac dysfunction as indicated by testosterone, PSA, lipid profile and troponin I levels. The LD₅₀ of 273.86 mg/kg body weight is indicative of mild toxicity. The lower than normal Hb, RBC confirms the possibility of toxicity.
Vitamin supplementation in Rauwolfia vomitoria root bark extract administration may interact and ... more Vitamin supplementation in Rauwolfia vomitoria root bark extract administration may interact and impact significantly on hematology of albino Wistar rats.
Uploads
Papers by Usenobong Ufot