Microbial population changes in tropical agricultural soil experimentally contaminated with crude petroleum

Impacts of crude petroleum pollution on the soil environment and microbial population dynamics as well as recovery rates of an abandoned farmland was monitored for seven months spanning the twomajor seasons in Nigeria with a view to establishing process conditions necessary for development of effective strategies for bioremediation. The physico-chemistry of the control and contaminated soilsdiffered just significantly (P < 0.05). Whereas these factors were relatively stable over the period of investigation for the control site, a downward trend was observed for the experimental. The pollutedsoil showed significant diversity in structure and number of flora .There was an initial drop in microbial population densities at the onset of pollution but, a gradual increase was observed thereafter. Highercounts of microflora were obtained for April, May, June and July samples which coincided with the onset and peak of wet season. A rapid and significant reduction in residual oil concentration wasobserved during this period. Overall, nearly 100% of the crude oil pollutant was degraded within the 28-week study period. The residual oil concentration gave a high but negative correlation coefficient (r = -0.84 to -0.90) with total heterotrophic and hydrocarbon-utilizing populations. On application of data generated to model equations, approximately 60.5 weeks would elapse before the contaminated soilcould recover from the impact of the oil. Our results show that a natural population readily able to degrade crude oil is present in the soil chosen for this study. However, it may be necessary to monitor the level of inorganic nutrients and adjust some appropriately to enhance biodegradation of the organic pollutant

Degradation of Aroclor 1221 by microbial populations of the Lagos lagoon

Samples obtained from three locations in the Lagos lagoon were studied for the effect of Aroclor 1221 on their population dynamics. In all three cases, both control and experimental microcosms showedslight increases between day 5 and day 10 with the highest value of 4 × 1010 cfu/ml in control and 1.2 ×1011, 8 × 1010 and 9 × 1010 cfu/ml for Iddo, Apapa and Tin Can samples respectively. Three isolatesnamely, Bacillus subtilis, Alcaligenes eutrophus and Pseudomona aeruginosa were obtained from the microcosms after successive enrichment. All the isolates grew readily on 100 ppm of Aroclor 1221concomitant with production of yellow metabolites in mineral salts medium. Whereas maximal growth was observed at day 12 on biphenyl, that of the polychlorinated biphenyl (PCB) mixture was on day 15.Generally, growth dynamics were similar irrespective of the substrate while typical generation times, with the exception of B. subtilis on Aroclor 1221, ranged insignificantly (P < 0.05) from 6.86 to 8.35 day,thus, suggesting that chlorine substitution has little or no effect on catabolic potentials of the organisms. The degradative capability of these strains suggest that they contribute immensely to theself-purification processes occurring in the lagoon, and this could be exploited for decontamination of PCB polluted aquatic ecosystems

Microbial assessment of the armpits of some selected university students in Lagos, Nigeria

A study of the carriage of microorganisms in armpits and prevailing factors was carried out on 80 students of the University of Lagos. The armpits were swabbed and the microbiological analyses were carried out on the swab samples. The organisms isolated include Staphylococcus epidermidis (35%), Staphylococcus aureus (3%), Staphylococcus cohnii (3%), Staphylococus haemolyticus (15%), Staphylococcus hominis (25%),Micrococcus luteus (9%), Staphylococcus capitis (6%), Staphylococcus saprophyticus (3%) and Candida tropicalis (1%). Questionnaires on gender and health related factors were administered to the subjects. Moststudents regardless of sex, used toilet soap (62.5%), had their bath twice daily (60%), used sponge for body scrubbing (87.5%) and shaved regularly (78.75%) but these did not have any significant influence on thecarriage of microorganisms (P = 0.05). More female participants used deodorants, than the males. The bacterial and fungal counts in the armpits of females were lower than the counts from male armpits, which means that the use of deodorant reduced the carriage of microorganisms. From the antibiotic sensitivity tests carried out on S. aureus, the highest sensitivity was recorded for Ofloxacin while the least was for  Cotrimoxazole. However the bacterium was resistant to most antibiotics tested. The DNA profile of S. aureus showed that none of the strains had a plasmid thereby suggesting that the antibiotic resistance genes in these strains could be chromosomally-encoded.Keywords: Microorganisms, armpit, university students, Lagos, Nigeria

Yeasts and bacterial biosurfactants as demulsifiers for petroleum derivative in seawater emulsions

Abstract Oil sludge or waste generated in transport, storage or refining forms highly stable mixtures due to the presence and additives with surfactant properties and water forming complex emulsions. Thus, demulsification is necessary to separate this residual oil from the aqueous phase for oil processing and water treatment/disposal. Most used chemical demulsifiers, although effective, are environmental contaminants and do not meet the desired levels of biodegradation. We investigated the application of microbial biosurfactants as potential natural demulsifiers of petroleum derivatives in water emulsions. Biosurfactants crude extracts, produced by yeasts (Candida guilliermondii, Candida lipolytica and Candida sphaerica) and bacteria (Pseudomonas aeruginosa, Pseudomonas cepacia and Bacillus sp.) grown in industrial residues, were tested for demulsification capacity in their crude and pure forms. The best results obtained were for bacterial biosurfactants, which were able to recover about 65% of the seawater emulsified with motor oil compared to 35–40% only for yeasts products. Biosurfactants were also tested with oil-in-water (O/W) and water-in-oil (W/O) kerosene model emulsions. No relationship between interfacial tension, cell hydrophobicity and demulsification ratios was observed with all the biosurfactants tested. Microscopic illustrations of the emulsions in the presence of the biosurfactants showed the aspects of the emulsion and demulsification process. The results obtained demonstrate the potential of these agents as demulsifiers in marine environments

Microbial Community Analysis of a Coastal Salt Marsh Affected by the Deepwater Horizon Oil Spill

Conceived and designed the experiments: MJB RJM BM PAS. Performed the experiments: MJB RJM SR JP YMP LMT JDVN. Analyzed the data: MJB RJM YMP LMT GLA TCH JDVN JZ PAS. Contributed reagents/materials/analysis tools: GLA TCH JZ BM PAS. Wrote the paper: MJB RJM PAS.Coastal salt marshes are highly sensitive wetland ecosystems that can sustain long-term impacts from anthropogenic events such as oil spills. In this study, we examined the microbial communities of a Gulf of Mexico coastal salt marsh during and after the influx of petroleum hydrocarbons following the Deepwater Horizon oil spill. Total hydrocarbon concentrations in salt marsh sediments were highest in June and July 2010 and decreased in September 2010. Coupled PhyloChip and GeoChip microarray analyses demonstrated that the microbial community structure and function of the extant salt marsh hydrocarbon-degrading microbial populations changed significantly during the study. The relative richness and abundance of phyla containing previously described hydrocarbon-degrading bacteria (Proteobacteria, Bacteroidetes, and Actinobacteria) increased in hydrocarbon-contaminated sediments and then decreased once hydrocarbons were below detection. Firmicutes, however, continued to increase in relative richness and abundance after hydrocarbon concentrations were below detection. Functional genes involved in hydrocarbon degradation were enriched in hydrocarbon-contaminated sediments then declined significantly (p<0.05) once hydrocarbon concentrations decreased. A greater decrease in hydrocarbon concentrations among marsh grass sediments compared to inlet sediments (lacking marsh grass) suggests that the marsh rhizosphere microbial communities could also be contributing to hydrocarbon degradation. The results of this study provide a comprehensive view of microbial community structural and functional dynamics within perturbed salt marsh ecosystems.Yeshttp://www.plosone.org/static/editorial#pee

Barriers to Herbal Medicine Research in Nigeria; Researcher’s Perspective: A Review

This paper presents the barriers to herbal medicine research in Nigeria. This is with a view to formulating appropriate strategies that would be deployed to overcome the identified barriers to herbal medicine research. The paper therefore identified and discussed some of these inherent barriers such as the standardization of herbal medicines according to western pharmaceutical clinical standards which is anchored on a single-active-ingredient approach; attitudes and perceptions of agonists of orthodox medicine; influence of traditional medicine practices on herbal medicinal products; problem of patenting inventions by researchers; lack of linkages between universities, research centres and the industries; decay of research and development (R&amp;D) infrastructure; and government under-funding of R&amp;D activities. The paper concluded that research in herbal medicine in Nigeria needs to be improved upon. In order to do this, herbal medicine researchers should make deliberate effort to choose, acquire, adopt, use, adapt, manage and master foreign technologies to suit local use (indigenous technology) which would enable the mass production of herbal medicines that will meet internationally acceptable standards. Government should increase R&amp;D funding, encourage patency, and encourage the facilitation of effective linkages and partnerships between the universities, research centres and the industries. Finally, government should ensure industrial peace, and a sound educational system imbued with congenial intellectual capacity and salubrious environment.Key words: Herbal medicine, research, barriers, Nigeria

Developing a Framework for Ethnomedicine Innovation System in Nigeria

This paper examines the interactions within the national Innovation System in order to develop a framework for an Ethnomedicine system for Nigeria. The strength, weakness, opportunity, and threat inherent in the existing national Innovation System were examined and a modified framework was proposed by the creation of a linkage between the Local National Innovation System Structure and the Developed World&#8217;s National Innovation System. This proposed linkage is expected to be fast-tracked through Foreign Direct Investment (FDI) flow, in form of technology transfer, technical collaboration, technical assistance, technology-based strategic alliances, among others in the field of ethnomedicine. Through this linkage, the acquisition of tacit knowledge, product and process know-how, better management practices, skill, critical mass, best practices in advanced technologically superior operations needed to upgrade the value of Nigerian ethnomedicine research could be realized, through technological spillover since medicine plants are plentiful in Nigeria

Degradation of aviation fuel by microorganisms isolated from tropical polluted soils

The degradation of aviation fuel was observed in soil samples from a polluted site at the aviation fuel depot, Lagos Airport, Nigeria. The percentage of occurrence of bacterial aviation fuel&ndash;utilizers were less than1.0% of the heterotrophic populations, while the fungal-degraders were between 2.547-16.053%. There were no significant statistical differences for both the bacteria and fungi estimations among the soil samples.Enrichment of soil samples with aviation fuel resulted in the isolation of five bacteria (Pseudomonas aeruginosa, Micrococcus luteus, Corynebacterium sp., Flavobacterium rigense, Bacillus subtilis), three yeasts (Rhodotorula sp., Candida tropicalis, Saccharomyces sp.) and two molds (Aspergillus niger, Penicillium sp.). Utilization of the substrate by bacteria and yeast isolates resulted in an increase in population density and subsequent decrease in pH value and residual aviation fuel concentration. Over 90% of the n-alkane fraction of the aviation fuel supplied at 0.5% v v-1 concentration was degraded in 14 days by Pseudomonas aeruginosa,Micrococcus luteus and Corynebacterium sp. There were differential growth responses by the strains to dodecane, benzene, toluene and naphthalene, while growth was not supported by hexane and cyclohexane.Thus, enrichment with of soil contaminated with aviation fuel led to the isolation of competent hydrocarbon degraders

Morphological characterization and evaluation of heat tolerance traits in Nigerian goat breeds

There are three main breeds of goat in Nigeria: The West African Dwarf (WAD), the Red Sokoto and the Sahel. Goats are renowned for their hardiness and can survive in most environments. The goats sampling was carried out from farms and markets across different states in Nigeria, according to the geographical distribution of the breeds published by Blench (1999). This experiment was carried out to analyse morphological variability among Nigerian goats. A total of 318 goats spread across the three Nigerian breeds were used in the following populations (57 Sahel, 187 Red Sokoto and 137 West African Dwarf). Data were collected on body weight, linear body measurements and heat tolerance traits and were subjected to analysis of variance using the fixed effects of breed, sex and location. Results showed that breed, sex and location significantly (P&lt;0.05) affected all the linear body measurements and heat tolerance traits. The Sahel breed had the highest values in most of the measured traits compared to the West African Dwarf and the Red Sokoto breeds of goat. It was observed that goats from the northern part of Nigeria were heavier than their southern counterparts, and this can be likened to their genetic makeup and the extent of its interaction with the environment. The results of the study confirmed the population structure of Nigerian goat breeds and showed that they possess enough diversity to enhance genetic improvement for higher survival and productivity.Keywords: Goat, Breed, Traits, Respiratory rate and Pulse rat