Theses and Dissertations

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Open Access
Pollution Pattern in the Mokuro Dam in Ile-Ife
(Obafemi Awolowo University, 1984) Petters, Hannah Itam; Odeyemi, Olu
Bacteriological and physical-chemical analyses of the Mokuro Jam (in Ile-Ife) an its distribution system were carried out from December 1982 to November 1983 at monthly intervals, and the quality of water was assessed to establish the pollution pattern. Generally, the population density of aerobic heterotrophic bacteria varied between wet and dry seasons., While thorn was an increase in the mean monthly population of bacteria from 4.2 x 102/ml in November to 4.8 x 106/ml in February (i.e. dry season) there was a comparative decrease from 11.0 x 106/ml in June to 1.8 x 103/ml in October (i.e. rainy season), in the distribution system In the stream and in the dam, the seasonal trends of total aerobic bacterial distribution followed more or less the same pattern as in the distribution system. In the dam, the faecal coliform populations ranged from zero to 33 MPN/100 ml during the rainy season and from 2 to 221 MPN/100ml in the dry season. The same pattern was observed in the distribution system. Both faecal streptococci and Clostridium perfringens were also detected in the water samples with no definite pattern of population distribution between the seasons. The mean monthly faecal streptococci ranged from zero to 2.8 x 10 4/mt, while Clostridium perfringens ranged from zero to 538 MPN/100ml. Nitrate, phosphate, chloride and dissolved solid levels were generally low. These compounds ranged from zero to 1.16 mg/l; from zero to 0.038 mg/I, from 3.6 to 54 mg /l, and from 0.0001 to 0.058 g/100ml, respectively. The BOD varied with a range of 1.0 to 12.6mg /l in the dam. In the distribution system, the chlorine residual was generally below 1mg/l, decreasing with distance away from the chlorination point.
Open Access
The General Characteristics and Cultivation of some Nigerian Mushrooms
(Obafemi Awolowo University, 1985) Alofe, Folaranmi Victoria; O.L., Oke; O.A., Afolabi; S.R.A., Adew usi; O., Odeyemim
Sixteen mushroom species, namely, Agrocybe broawayi, Chlorophyllum molybdits, Coprinus africanus, Coprinus congregatus, Lentinus subnudules, Lepiota bionata, Plerotus tuber-regium, Psathyrella atroumbonata, Termi tomyces microcarpus, Termitomyces robustus, Termitomyces striatus, Termitomyces species, Tricholoma lobayensis Volvariella esculents, Volvariella speciosa, and an unidentified species were studied. Maltose- and glucose-glutamic acid liquid media suported good mycelial growth of the five species investigated. Some of the species contain various amounts of protein, fats, fiber, and carbohydrates. Mycelial growth of the five species investigated was temperature and pH dependent. Minimal and maximal growth temperatures were 10°C and 40°C respectively for each of the species. Optimal temperature requirements varied between 25°C and 40°C. The mushroom species grew best around pH values of 6.5 and 7.0 The greatest amount of protein (>50%) occurred in V. esculenta. Most of the mushrooms contained the major as well as the trace elements in measureable concentrations. Aluminium occurred in very high concentrations in all the species tested. Arsenic was virtually absent in all the mushroom species studied. Alkaloids and tannins were detected in most of the species tested. Saponins were not detectable in any of the species analysed. C. molybditis was as good as casein in promoting growth of white albino rats, but it made such rats extremely excited and aggressive. T. straatus was found to be highly toxic. All the rats that were fed on a diet containing the mushroom died within 4 days. P. tuber-regi um and P. atroumbonata were successfully cultivated in the field. C. congregates and T. lobayensis were cultivated in the laboratory using Blighia sapida and Terminalia ivorensis (Black Afra) wood chips together with their saw dust.
Open Access
Studies on Protease from Aspergillus Aculeatus
(Obafemi Awolowo University, 1985) Elegbe, Isaac Anuolowapo; Olutiola, P.O.
Aspergillus aculeatus associated with the black tongue disease was able to grow in liquid synthetic medium. Growth was maximum on the fifth day of incubation. Growth was optimum at pH 6.5 and 35 °c. The best carbon source for growth was glucose while among the nitrogen sources used, optimum growth occurred on tryptone. During growth of A. aculeatus in liquid synthetic medium, proteins were released and proteolytic activity was detected. Proteolytic activity was optimum when the sole carbon and nitrogen sources were galactose (or inositol) and peptone respectively. The proteins were separated into three peaks of absorption by gel permeation chromatography, and only one of the components exhibited proteolytic activity. The molecular weight of this protease from its elution volume on Sephadex G-100 was approximately 28,500 Daltons. Ion exchange chromatography resolved only one peak of absorption with a purification fold of approximately 309.5, a specific activity of 2.7 x 10' units/mg protein, and a Km of approximately 0.26 mg/ml for the hydrolysis of casein. The partially purified enzyme was able to hydrolyse casein, lactalbumin, egg albumin and human haemoglobin. Optimum activity of the enzyme occurred at pH 6. 5 and 40 °C. Activity of the enzyme was stimulated by low concentrations of Cu++, Ba++, Ca++, Mg++ and K+ but inhibited by Mn++, Zn +, Fe +, Hg++, iodoacetic acid and ethylene diamine tetraacetic acid. The enzyme was highly susceptible to heat, losing all its activity within 2 minutes at 70 °C. Intraperitoneal inoculation of white rats (Fisher's breed) with the crude and the partially purified enzyme caused marked histological changes resulting in cellular degeneration and local necrosis of three major organs (liver, kidney and spleen). The partially purified enzyme was more effective than the crude enzyme, and the changes produced by both enzymes were more pronounced in the male than in the female rats.
Open Access
Purification and some Biochemical and Immunological Characterization of a Protease from Serratia Marcescens
(Obafemi Awolowo University, 1986) Obiallor, Nkem Nicholas; Sonukan, Olusola
An extra cellular protease purified 30-fold was induced in cultures of Serratia marcescens (NCIB 1377) during growth in liquid synthetic medium containing vitamin-free casein (sigma) as the inducer. Purification was by means of ammonium sulphate precipitation and chromatography on sephadex G-100 and DEAE-sephadex (A-50) columns. The molecular weight estimated by gel filtration was approximately 45,000. Optimum temperature and pH of activity, using casein as substrate were 40oc and 8.5 respectively. The protease was stable for 60 minutes at 30-40oC, losing all detectable activity at 60oC, even for 10 minutes. Ca++ and Mg++ did not affect the enzyme activity. Sulfhydryl reagents, IAA, dithiothreitol and L-cysteine could not inhibit its activity; and metal chelators, dithizone and NacN failed to be inhibitory to the protease activity. However, EDTA, at relatively high concentrations inhibited the protease activity. Inhibition of enzyme activity by 2,4-Dinitrophenol indicated need for metabolic energy in enzyme activity. The protease was well inhibited by PMSF indicating it is a serine enzyme. The protease digested a wide range of proteins but with a preference for the milk proteins. It possessed an apparent km of approximately 0.75mg/ml for casein. The sephadex G-100 fraction of the protease was used to raise antibodies in locally bred rabbit. The antibody to this protease was found to inhibit its enzymic activity. Ouchterlony double-diffusion tests revealed antigenic relatedness between all the enzyme fractions at the different stages of purification. The protease shares no antigenic.
Open Access
Studies on the Natural Antifungal Compounds from Yam tubers (Dioscorea Alata. L.).
(Obafemi Awolowo University, 1986) Aderiye, Babatunde Idowu; Ogundana, S.K.
In order to investigate the biochemical basis of natural resistance of yam peel to fungal infection, a preliminary chromatographic bioassay of four varietal species of Dioscorea; Manihot esculentum Crantz; Solanum aethiopicum Linn.; and Xanthosoma sagittifolium Schott was undertaken. The studies revealed the presence of antifungal compounds from the peel extracts of the root crops. Four prominent antifungal components were obtained from the peels of Dioscorea alata L. out of which the component at Rf 0.38 was fully characterized. The component was identified with the aid of nuclear magnetic resonance, mass spectroscopy and colour reaction as sitosterol. It is a white crystalline solid with a melting point of 138oC. The antifungal activity of the compounds against the germination of spores of four yam pathogens showed a percentage inhibition of below 57% at a concentration of 50 ug/ml while inhibition on the elongation of ferm- tubes of Fusarium moniliforme was as high as 82% at the same concentration. However, the ED50 for inhibition of germ-tube elongation in the yam compounds for the same organism was below 27 ug/ml. β- sitosterol was found to have an effective inhibitory dosage against the yam pathogens and the test fungus ranging between 1.21 - 2.4 x 10-4M. The role of the yam compounds at high concentrations in disease resistance is discussed. The antifungal compounds have weak bacteriostatic properties with no definite pattern against both gram - positive and Gram - negative bacteria.
Open Access
Field Assessment of Some Local Cowpea Rhizobium Inoculants.
(Obafemi Awolowo University, 1986) Oloke, Julius Kola; Odeyemi, Olu
The effectiveness of lignite, sub-bituminous, cow manure and peat as rhizobia carriers and inoculants were assessed in a field plot. The inoculants prepared by incorporating each of three rhizobia strains (IFE CR9, IFE CR15 and R. japonicum) into each of the carrier materials were used to inoculate three cowpea varieties viz. TVU 1190, IT82E-60 and Ife brown. When lignite bearing IFE CR9 was used to inoculate TVU 1190 plants, the nitrogen content of the plants was found to be 178.12mg/plant whereas that of the uninoculated nitrate free plants was 64.07mg/plant. As a result of using lignite, sub-bituminous, peat, and cowdung as carriers for the rhizobia strains, the increases in the grain yield of the inoculated cowpea plants were 72.2%, 51.9%, 25.5% and 10.1% respectively when compared with the uninoculated ones. IFE CR9 (which is a native Rhizobium) seems to be better adapted to tropical conditions than the imported R. japonicum. When Ife brown cowpea plants were inoculated with IFE CR9 incorporated into lignite, the nitrogen content of the plants was 149.00mg/plant whereas the nitrogen content of the same plants inoculated with R. japonicum in lignite was 132.61mg/plant. TVU 1190 cowpea variety responds better to inoculation than the two other varieties. For example when TVU 1190, Ife brown and IT82E 60 were inoculated, the increases in dry weight of the plants over the uninoculated ones were 125.1%, 116% and 93.3% respectively.
Open Access
Post-infectional Production of Phytoalexin in White Yam (Discorea Rotundata Linn.) Innoculated with Botryodiplodia Theobromae Pat
(Obafemi Awolowo University, 1986) Fagbohun, Dayo Emman; Ogundana, S. K.
Four phytoalexins were induced D. rotundata in post-infectionally with B. theobromae. Three of the Phytoalexins were isolated and identified with the aid of ultra-violet mass and nuclear magnetic resonance spectral data as 3,2,5 trihydroxydiphenyl 1 , 2 ethane; 3, 5 dihydroxydiphenyl 1,2 ethane; 1,5 dihydroxy-3-methoxydiphenyl 1,2 ethane and an uncharacterised. Maximum production of the phytoalexins was achieved at 30 hours of incubation. Chloroform: methanol, (96:4 v/v) gave the best separation of the phytoalexins from yam crude extract. Antifungal activities of the phytoalexins against spore germination varied according to fungal species but the pores were more sensitive to 3, 2, 5 trihydroxydiphenyl 1,2 ethane than 3, 5 dihydroxydiphenyl 1,2 ethane and the spores of B. theobromae were least affected. The ED50 values required to prevent spore germination of the pathogen varied from 45.7 µg/ml 58.9 µg/ml for 3,2, 5 trihydroxydiphenyl 1,2 ethane and 45.6 µg/ml to 81.3 µg/ml ;3,5 dihydroxydiphenyl 1,2 ethane. The ED50 value of the two phytoalexins to prevent germ tube elongation of the yam rot pathogens was highest for B. theobromae (61.07 µg/ml) and least for A.niger (46.77 µg/ml). The compound 3,2, 5 trihydroxydiphenyl 1 ,2 ethane was found to be active against the four bacterial species tested against it even at the low concentration of 10 µg/ml.
Open Access
Post-harvest Rots of Tomato Fruits
(Obafemi Awolowo University, 1986) Fakorede, Adekunle; Ogundana, S. K
In a study of post-harvest fruit rot disease of tomatoes in South western Nigeria, the soft watery rot was the most prevalent accounting for more than 60% of total fruit rots during the rainy season. Aspergillus niger, Geotrichum candidum, Mucor hiemalis and Pichia kluyveri were organisms established as incitants of the rot. A. niger and G. candidum were major virulent pathogens while M. hiemalis and P. kluyveri were mild ratters. Rotting was most serious at temperatures of 25 - 30°C which, in fact, coincides with the optimum temperature for growth of the pathogens. The pathogens thrived best in tomato decoction media and at high relative humidity levels of 85 - 95%. Culture filtrates of the pathogens grown on different carbon substrates produced extracellular cellulase and Polygalacturonase (PG) enzymes. The production of cellulose was more pronounced than that of PG in all pathogens except niger which produced the two types of enzymes appreciably. Brestan, Bordeaux mixture and Thiabendazole proved effective in controlling the growth of all the pathogens at low concentrations of 250 mg/dm-3 (a.i) while Benomyl and fundazol were effective against A. niger at concentrations of 500 and 1 50 mg/dm-3 (a.i.) respectively.
Open Access
Geomagnetic Deep Sounding of Southwestern Nigeria.
(Obafemi Awolowo University, 1987) Arubayi, John Blackie; Alabi, A. O.
Five modified version of Gough-Reitzel's magnetometers were operated between December 1985 and March 1986 at five locations: Ibadan (IBD), Ile-Ife (IFE), Ise-Ekiti (ISE), Igbile (IGB) and Okitipupa (OKT). The magnetometer array experiment was to aid the study of the magnetic field variations of part of south-western Nigeria, and to deduce the general geologic nature of the subsurface in this area. Five night-time and two day-time disturbance events selected from the suite of observed magneto grams were used in the analysis. To process the magnetic data a home-made digitizer was contrived and spectral analysis computer soft-ware programs were developed and implemented on a TRS-80 Radio Shack micro-computer system. Features of the computer package are described in details in the thesis. Magneto grams of the day-time events exhibit large amplitude north-south horizontal component (H) with enhanced vertical field (Z) at IBD. The H-field also decreases toward the coastal stations from IBD. These are indicative of the spatial non-uniformity in the equatorial source field. In all the night events, the spatial uniformity of the source field over the area of study is obvious from both magneto grams and the plot of the amplitude of the Fourier spectra for H and D components for all the stations. The coherence plots with IFE as reference station also confirm the uniformity of the source field. Both magneto grams and the plot of spectra amplitude also show strong correlations of the Z-field with the H-field and none with the D-field. The Z-field also diminishes inland. This is a clear exhibition of coast effect. Plots of Z/H at selected peak periods were made with H defining the horizontal field component which shows maximum correlation with Z-field component. Values of Z/H at the period of 60min. when interpreted with similar curves by White and Polatako (1978) show that the rate of decrease of the coast effect inland is more rapid than what Everett and Hyndman (1967) proposed for the shield region of Australia. A possible explanation could be the presence of a transitional region between the shield and the ocean. Similar results were obtained for South Australia by White and Polatako (ibid). Plots of induction arrows at 42min. period at all the stations point to the 500m fathom line, indicating current concentration in the deep ocean adjoining the coast. Arrows at period of 25min. however point westward at IFE. This could be due to additional inland anomaly. A two layered earth model attempted for observed data for IFE showed depth to increased conductivity as 340km. This is contrary to earlier models which obtained depth to ultimate conducting layer as less than 100km which gives erroneous impression of on-going tectonic processes in this area. To infer the detail features of geologic structure in the area from obtained data, a programme of stripping the coast effect which is the dominant anomaly recorded suggested for further studies.
Open Access
The Importance of Macrophages, T-Lymphocytes and Passive Transfer of Antibody in the Protection of Mice against Shigella Dysenteriae Type 1.
(Obafemi Awolowo University, 1987) Koleosho, Tinuola; Shonukan, O.O.
The contribution of T-lymphocytes, macrophages and antibodies to protection against Shigella dysenteriae type 1 during the course of infection in mice was analysed following intraperitoneal injection of the organism into mice. Approximately 1.55 x 105 cells of Shigella dysenteriae was injected into each mouse. At intervals, the liver and spleen were dissected out to obtain fresh isolates of the organism from these organs. Ten minutes after the inoculation, ~1.59x,04 and 4.79x103 Shigella cells were recovered from the liver and spleen respectively. The number of trapped bacteria decreased from 10 mine to reach minimal levels by 6 hours and then increased to reach maximum levels by 24 hours; gradual elimination occurred after 3 days. Carrageenan (a toxic macrophage blocker) was injected into another set of mice 24hours prior to infection with Shigella. Carrageenan treatment significantly (p<0.05) enhanced the bacterial growth in the liver and spleen. This observation suggests that carrageenan sensitive macrophages are very important in the protection against Shigellosis. The role of antibody was investigated in a serum transfer experiment, AntiShigellae antibody that was raised in Rabbit was used to passively immunize another set of mice 24hours prior to the challenge with Shigellae. It was observed that although antibody was produced (titer 1:320), it had no protective role on passive transfer. The contribution of T-cells to protection was examined in another set of mice by immunosuppressing T-cells with antithymocytic serum (ATS) 24hours prior to challenge with Shigellae. The ATS was raised in Rabbit injected with thymocytes pooled from another set of mice. There was a significant (p<0.05) increase in bacterial count in ATS treated mice, showing that T-cells also play a significant role in protection against Shigella. It seems that that the protection of mice against Shigella dysenteriae depends on the synergistic action of macrophages and T-Iytphocytes.
Open Access
Production and Characterization of Biosurfactants from Petroleum Degrading Aquatic Bacteria
(2015-03-20) Adedeji, Yewande Olufunto
This study was undertaken to produce, isolate and characterize biosurfactants from oil degrading bacteria using various carbon sources and determine the conditions under which specific oil degrading bacteria will produce optimally, biosurfactants required for optimal oil degradation. Six bacterial isolates, namely Bacillus subtilis, Proteus vulgaris, Pseudomonas putida, Pseudomonas oleovorans, Sarcinae litoralis and S58 (an unidentified bacteria) were maintained on nutrient agar slants and subcultured every forthnight. Standardized cultures (1.0 ml) of the bacteria isolates were inoculated into 100 ml capacity conical flasks each containing 50 ml mineral salts medium (MSM) and 0.2 % (v/v) Escravos light crude oil was aseptically added as the sole carbon source. The cultures were agitated in an incubator shaker at 37 °C for a week. The presence and activities of the biosurfactants produced by each bacterial isolate was detected using the swirling beaker method. The growth rates of the bacteria were measured using a spectrophotometer and the best condition of pH, temperature, salinity, concentrations of nitrogen, iron, and magnesium ions which each bacterial species produced optimally were studied. The biosurfactants were isolated and characterized spectrophotometrically between 380 nm and 700 nm and chemically by spraying the TLC chromatograms with specific reagent such as iodine. The result showed that the maximum absorption wavelength of the iodine-polysaccharide complex was almost the same for each biosurfactant from the various bacteria and ranged from 380 nm to 420 nm, which was characteristic of a polyglucose unit. The reducing sugars from all the samples proved to be glucose units. A long chain fatty acid was obtained from all the samples which exhibited Rf values close to that of Myristic and Stearic acids. The results further revealed that all the isolates emulsified oil in the swirling beaker test, indicating the presence of biosurfactants. The biosurfactant produced was composed of polyglucose units and fatty acid which is characteristic of glycolipids. During the growth of these bacteria on crude oil-MSM, the oil was degraded best at 28 °C and pH 6.8 and 7.2. Biosurfactant production increased at concentrations of 0.5 % w/v for NaCl and magnesium but decreased as the concentration was increased to 1.0 % w/v and later to 1.5 % w/v. Production of biosurfactant increased at a concentration of 1.0 % w/v for nitrogen. The bacteria produced biosurfactant when diesel was used as the sole source of carbon. It was concluded that the bacteria employed in this study would be useful in the biodegradation of oil in petroleum contaminated sites because of their ability to produce biosurfactant and emulsify crude oil.
Open Access
Mechanism of Immunity against Campylobacter Jejuni in Mice
(2015-04-20) Ewuola, Kola Sambakeyu
The roles of B-lymphocytes, T-lymphocytes and macrophages in the mechanism of immunity against Campylobacter jejuni in mice were investigated. This was done in an attempt to proffer solution to the problem of diarrhea through the enhancement of the immune mechanism involved in the protection against this agent. The roles of B-lymphocytes, T-lymphocytes and macrophages were investigated by injecting different sets of mice with carrageenan, anti-C-jejuni serum, and anti-thy mocytic serum obtained from rabbit respectively after being injected with I ml of C-jejuni cell suspension containing approximately 4.6x104 cells were sacrificed at one-day, three- day, five- day, and seven-day intervals. The liver and the spleen were removed, homogenized, serially diluted, plated and incubated for bacterial cell count. The data collected were subjected to statistical analysis using student’s t-test. The result showed that higher bacterial populations were found in the organs (liver and spleen) of the carrageenan-treated mice than in the control mice within the first twenty four hours post infection. Since this substance was toxic, the high bacterial population organs indicated that the macrophages were rendered inactive. However, a fall in the bacterial population later in the course of infection was observed. In the liver of the mice that were given anti-thy mocytic serum, the activity of the T-lymphocytes was hindered till seventy two hour post infection as shown by high bacterial count in this organ. Thereafter, there was a decrease in bacterial population which implied that the T-Iymphocytes had become more active in fighting the bacteria as a result of the loss of inhibitory potency by the anti-thymocytic serum. In the spleen of experimental set of mice, the bacterial count remained lower than in the control (t=. 0 0 0 , p=1.000, P> 0.05) mice throughout the period of the experiment. In the passively immunized mice, growth patterns in both the liver and the spleen were similar to those of control within the first twenty four hours post infection ( t = 632, P= 561 P> 0.005) In the liver, an increase in bacterial population was observed after twenty four hours (t = 2.828, P =.047, P<0.05) while in the spleen, there was an increase in bacterial count Followed by a decrease in population (t= 5.330, p = 0.06 p<0.05). The result showed that at some stages in the course of infection, there existed significant difference (P<0.05) in the means of the bacterial populations in the liver and the spleen. The study concluded that macrophages. T-lymphocyte and antibody complemented one another in effecting immunity to this diarrhea-causing pathogen in the mice. This implied that the immune mechanisms involved were both cellular and humoral.
Open Access
A Study of Antibiotics Susceptibility Profile of Clinical Bacterial Isolates in Ile-Ife and the Minimum Bactericidal Concentrations of Selected Antibiotics
(2015-05-04) Oladapo, Oluwabunmi Oluwatoyin
The study evaluated the minimum inhibitory concentrations (MIC) and the minimum bactericidal concentrations (MBC) of selected antibiotics. This was with a view to determine the antibiotic resistance profile of selected bacterial isolates from clinical sources in Ile-lfe. Clinical specimens were taken from 196 patients from Obafemi Awolowo University Teaching Hospitals Complex (OAUTHC), Seventh Day Adventist Hospital (SDAH), Obafemi Awolowo University Health Centre (OAUHC) and Osun State Comprehensive Health Centre (OSCHC) in Ile-lfe from July 2005 to June 2006. A total of 222 bacterial isolates were cultured from the specimens. Using the broth macrodilution method, the MIC and MBC of some commonly used antibiotics in the environment were assayed. The antibiotic susceptibility patterns were determined by the Kirby-Bauer disc-agar diffusion method. Descriptive statistics was used to analyse the data. The results showed that out of 222 isolates tested, 86.04% were resistant to amoxicillin, 74.77% to cotrimoxazole, 65.76% to tetracycline and 59.46% to augmentin. Of the 145 isolates tested with nitrofurantoin, nalidixic acid and ofloxacin. 48.96°/x, were resistant to nalidixic acid, 43.50% to nitrofurantoin, and 13.10% to ofloxacin. The results also showed that the incidence of multiple resistant bacterial isolates in the four hospitals ranged from 91.9% for OAUHC to 94.8% for OSCHC. These values were higher than those recorded in previous studies in the same environment. The ratio of MIC to MBC revealed that some of the antibiotics had lost their effectiveness against the organisms on which they were tested. Ofloxacin (a quinolone) was found to be the most effective against pseudomonas aeruginosa with MBC/MIC ratio of 1 while gentamicin (an aminoglycoside) was the most effective against Staphylococcus aureus with MBC/MIC ratio of 1. The study concluded that the phenomenon of bacterial resistance to antibiotics is increasing and has become widespread in Ile-Ife.
Open Access
The Effects of Bacterial Enzymes and Biosurfactants on Hydrocarbon Degradation in a Crude Oil Polluted Fresh Water
(2015-05-05) Olajide, Patience Orobosa
The present work was designed to identify extracellular enzymes and biosurfactants from five bacterial isolates and investigate their actions on crude oil degradation as a means of bioremediation of hydrocarbon pollution. The Five bacterial isolates including Proteus vulgaris, Bacillus subtilis, Pseudomonas aeruginosa, Sarcinae litoralis, and Alcaligenes viscolatis were selected for the study based on their relatively high efficiency for crude oil utilisation and their wide occurrence in the Niger Delta basin of Nigeria. The types of enzymes produced by the selected isolates were determined using standard API ZYM kit they were produced in spent media. The activity of the enzymes on crude oil biodegradation was investigated using the enzyme inhibition method. Biosurfactants were extracted from cultures grown in a neutral medium (pH 7.0) containing 2% glucose, shaken at 150 rpm at 37°C for 7 days. Qualitative drop-collapse, blue agar plate, haemolytic, emulsification activity (E24), oil spreading techniques as well as the swirling beaker test were used to confirm the production of biosurfactant. The effect of pH, temperature and salinity concentration on biosurfactant production was evaluated using standard instrumental methods. Biosurfactants were evaluated using acid-precipitation followed by extraction using chloroform-methanol (2:1). The anthrone positive fraction of the biosurfactants was identified by measuring extract absorption in an iodine-polysaccharide complex using a spectrophotometer NOVASPEC II, (Pharmacia Biotech) at wavelengths range of 380 to 700 μm. Enzyme systems detected with the API ZYM kit varied depending on the growth substrate used. Enzyme inhibition slowed down degradation of crude oil and the enzyme activity behaved similarly over time whereas the effect of catalase, cytochrome c oxidase and lipase increased the biodegradation of crude oil in the enzyme cultures medium. All the microorganisms investigated produced highest biosurfactant in glycerol medium (1.26-1.64) mg/1 during a 48 h of growth. Biosurfactants production was optimum at pH 6.2 and 7.2 and temperature of 37°C and 2% NaCl. All biosurfactants emulsified oil to varying degrees with varying emulsification index (E24) with over 60% emulsification activity. They were all stable with temperature between 15 and 90°C and pH range of 4.2-10.2. Only three isolates haemolysed blood agar and formed dark blue halos on agar plates indicating the production of glycolipids. The complex formed between the reaction of iodine with the polysaccharide of the biosurfactants had a maximum absorption wavelength between 380 to 420 μm. In conclusion, the enzymes and biosurfactants produced by the investigated bacterial isolates were effective in degrading crude oil.
Open Access
Bacteriological Studies of Open Fractures at the Obafemi Awolowo University Teaching Hospitals Complex (O.A.U.T.H.C), Ile-Ife
(2015-06-26) Daniels, Folashade Victoria
This study was aimed at isolating the bacteria associated with open fractures, enumerating the antibiotic sensitivity profiles and production of enzyme with virulent potential which could increase the virulence/pathogenicity of such microorganism. Fractures were examined according to Gustilo and Anderson's classification as grade I (2.1%), grade II (29.8%), grade IIIa (36.2%) and grade IIIb (31.5%). Samples were taken from superficial swab, superficial biopsies, deep swabs as well as deep biopsies making a total of four samples per patient at presentation, A total of 180 samples obtained on day 1, 42 samples were obtained on day 3 and 26 were obtained on day 7.Each sample was introduced onto thioglycolate broth to enhance the growth of anaerobic organism. Serial dilutions were made from these samples and plated out on nutrient agar. Incubation was allowed for 24 hrs at 37°C for the viable cell counts at each presentation. The samples in thioglycolate broth were then incubated for 24h at 37°C. Positive samples were plated out onto differential medium so as to identify some of the isolates and selective medium. Negative cultures that demonstrated fowl smells were plated out onto lactose egg yolk milk agar and neomycin blood agar and incubated anaerobically using Gas Pak for 24h at 37°C and extended to seven days and beyond to aid the growth of strict anaerobes. Discrete colonies were further characterized by standard methods. The results showed the prevalence of open fractures was higher in male 37(78.7%) than in females (21.3%).The results showed that tibial fractures constituted 66.1% and were mainly from road accident (RTA). A total of 203 bacterial isolate were cultured from the forty-seven patients with 53 from superficial swabs, (52) from superficial biopsies, (52) from deep swabs and (46) from deep biopsies were cultured. Gram negative bacteria isolates constituted 53.2% of total bacterial, Escherichia coli was the commonest with 26 (12.8%) followed by Salmonella spp and Pseudomonas aeruginosa occurring at the rate of 8.9%. Gram positive cocci constituted 58(28.6%) with Staphylococcus aureus constituting 31(15.3%) and S. epidermidis constituting 27(13,3%). A high incidence of antibiotic resistance was observed against penicillins such as amoxicillin and cloxacillin with values 72(68.6%) and 28(58.3%) respectively for superficial specimens and 57(58.2%) and 15(31.9%) for deep samples. Bacteria isolates cultured were relatively resistant to tetracycline with values 57(54.%) and 41(41.8%) in superficial and deep samples respectively but considerably sensitive to gentamycin and nutrofurantoin while quinolones especially ofloxacin were noted for high effectiveness and against screened bacterial isolates. 75% and 87.5% of Staphylococcus aureus cultured produced lipase and DNase respectively from deep samples while all the Pseudomonas aeruginosa stains produced DNase with 77.5% and 75% lipase production in superficial and deep samples respectively. In conclusion, both Gram-positive and Gram-negative organisms were relatively sensitive to gentamycin especially Pseudomonas aeruginosa which is known for high resistance against most antimicrobials. Ofloxacin was also highly effective against Gram negative organisms.

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