Showing papers in "African Journal of Biotechnology in 2006"

Antioxidant activity, phenol and flavonoid contents of some selected Iranian medicinal plants

Abstract: In present study, we carried out a systematic record of the relative antioxidant activity in selected Iranian medicinal plant species' extracts. The total phenol varied from 24.1 ± 1 to 289.5 ± 5 mg g -1 in the extracts. Flavonoid contents were between 25.15 ± 0.8 and 78.3 ± 4.5 mg g-1. 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging effect of the extracts was determined spectrophotometrically. The highest radical scavenging effect was observed in Mellilotus officinalis with IC50 = 0.018 mg ml –1. The potency of radical scavenging effect of M. officinalis extract was about 4 times greater than synthetic antioxidant butylated hydroxy toluene (BHT). The greater amount of phenolic compounds leads to morepotent radical scavenging effect as shown by M. officinalis extract

An overview of molecular marker methods for plants

Abstract: The development and use of molecular markers for the detection and exploitation of DNA polymorphism is one of the most significant developments in the field of molecular genetics. The presence of various types of molecular markers, and differences in their principles, methodologies, and applications require careful consideration in choosing one or more of such methods. No molecular markers are available yet that fulfill all requirements needed by researchers. According to the kind of study to be undertaken, one can choose among the variety of molecular techniques, each of which combines at least some desirable properties. This article provides detail review for 11 different molecular marker methods: restriction fragment length polymorphism (RFLP), random amplified polymorphic DNA (RAPD), amplified fragment length polymorphism (AFLP), inter-simple sequence repeats (ISSRs), sequence characterized regions (SCARs), sequence tag sites (STSs), cleaved amplified polymorphic sequences (CAPS), microsatellites or simple sequence repeats (SSRs), expressed sequence tags (ESTs), single nucleotide polymorphisms (SNPs), and diversity arrays technology (DArT).

Evaluation of the chemical composition of two Nigerian medicinal plants

Abstract: Nigerian medicinal plants (Aspilia africana and Bryophyllum pinnatum) were analyzed for their chemical composition, vitamins and minerals. The results revealed the presence of bioactive constituents comprising alkaloids (1.24 to 1.48 mg/100 g), saponins (1.46 to 1.72 mg/100 g), flavonoids (1.46 to 1.86 mg/100 g), phenols (0.06 mg/100g) and tannins (0.04 to 0.5 mg/100g). The medicinal plants contained ascorbic acid (26.42 to 44.03 mg/100 g), riboflavin (0.20 to 0.42 mg/100 g), thiamine (0.11 to 0.18 mg/100 g), and niacin (0.02 to 0.09 mg/100 g). These herbs are good sources of minerals such as Ca, P, K, Mg, Na, Fe and Zn. The importance of these chemical constituents is discussed with respect to the role of these herbs in ethnomedicine in Nigeria.

A bioseparation process for removing heavy metals from waste water using biosorbents

Abstract: The removal of heavy metals from our environment especially wastewater is now shifting from the use of conventional adsorbents to the use of biosorbents. The presence of heavy metals in the environment is of major concern because of their toxicity, bioaccumulating tendency, and threat to human life and the environment. In recent years, many low cost sorbents such as algae, fungi bacteria and lignocellulosic agricultural by-products have been investigated for their biosorption capacity towards heavy metals. In this comprehensive review, the emphasis is on outlining the occurrences and toxicology of heavy metals and the biosorption capacity of biosorbents compared to conventional adsorbents. A detailed description of the adsorption properties and mode of action of these biosorbents is offered in order to explain the heavy metal selectivity displayed by these biosorbents. The role of cell structure, cell wall, micropores and macropores is evaluated in terms of the potential of these biosorbents for metal sequestration. Binding mechanisms are discussed, including the key functional groups involved and the ion-exchange process. Quantification of metal-biomass interactions is fundamental to the evaluation of potential implementation strategies, hence, sorption isotherms, sorption kinetics, intraparticle diffusivities as well as models used to characterize biosorbent sorption are reviewed. The sorption behavior of some biosorbents with various heavy metals is summarized, their relative performance evaluated and a bioseperation process flow diagram for heavy metal removal from wastewater using biosorbents was proposed.

Solubilization of inorganic phosphates by fungi isolated from agriculture soil

Abstract: Most agricultural soils contain large reserves of phosphorus (P), a considerable part of which accumulates as a consequence of regular applications of P fertilizers. However, a greater part of soil phosphorus, approximately 95‐99% is present in the form of insoluble phosphates and hence cannot be utilized by the plants. In the present study fungal strains isolated from agriculture soil, having potential to solubilize insoluble inorganic phosphates were characterized. Two fungal isolates were tested for their tricalcium phosphate (TCP) solubilization efficiency in both solid and liquid medium. Isolates were identified as Aspergillus sp. and Penicillium sp. depending upon their colony morphology and microscopic studies. Phosphate solubilization was related to pH decrease caused by growth of fungus in medium containing glucose as carbon source. Aspergillus sp. solubilized 480 �g/ml of phosphorus, while Penicillium sp. solubilized 275 �g/ml of phosphorus from 0.5% tricalcium phosphate after 4 and 3 days of growth respectively. Both the strains show diverse levels of phosphate solubilization activity in liquid broth culture in presence of various carbon and nitrogen sources. Drop in pH during growth was more prominent in absence of TCP in the liquid medium. This indicates that absence of soluble P in media induces the acid production. Phosphate solubilizing microorganisms convert insoluble phosphates into soluble forms generally through the process of acidification, chelation and exchange reactions. Thus such microorganisms may not only compensate for higher cost of manufacturing fertilizers in industry but also mobilizes the fertilizers added to soil.

Sorghum grain as human food in Africa: relevance of content of starch and amylase activities

Abstract: Sorghum is a staple food grain in many semi-arid and tropic areas of the world, notably in Sub-Saharan Africa because of its good adaptation to hard environments and its good yield of production. Among important biochemical components for sorghum processing are levels of starch (amylose and amylopectin) and starch depolymerizing enzymes. Current research focus on identifying varieties meeting specific agricultural and food requirements from the great biodiversity of sorghums to insure food security. Results show that some sorghums are rich sources of micronutrients (minerals and vitamins) and macronutrients (carbohydrates, proteins and fat). Sorghum has a resistant starch, which makes it interesting for obese and diabetic people. In addition, sorghum may be an alternative food for people who are allergic to gluten. Malts of some sorghum varieties display α α α α-amylase and s-amylase activities comparable to those of barley, making them useful for various agro-industrial foods. The feature of sorghum as a food in developing as well as in developed countries is discussed. A particular emphasis is made on the impact of starch and starch degrading enzymes in the use of sorghum for some African foods, e.g. “to”, thin porridges for infants, granulated foods “couscous”, local beer “dolo”, as well agro-industrial foods such as lager beer and bread.

The nutritional value of fourteen species of edible insects in southwestern Nigeria

Abstract: Seventeen species of edible insects representing nine families from south western Nigeria were analyzed for nutrient composition. They include the orders of Orthoptera, Lepidoptera, Coleoptera, Hymenoptera, and Isoptera. Analeptes trifasciata , Rhynchophorus phoenicis and Zonocerus variegatus has the highest crude protein content (29.62, 28.42 and 26.8%, respectively). The Ether Extract content ranged from 1.50 to 31.40%, and the highest amount was found in R. phoenicis (31.4%), Macrotermes bellicosus (28.2%) and Macrotermes notalensis (22.5%). The nitrogen free extract content ranged from 38.5 to 85.3%, with highest values in Brachytrypes spp. and Oryctes boas. The insect richest in Vitamin A, B 2 and C was Apis mellifera (12.44 ug/100 g, 3.24 mg/100g and 10.25 mg/100 g, respectively). Highest calcium and phosphorus contents of 61.28 mg/100g and 136.4 mg/100g were found in Analeptes trifasciata . Iron was found highest in M.notalensi and magnesium in Zonocerus variegatus . These insects which are sources of delicacy are also pests of certain crops at developmental stages of their life. Despite this they constitute a significant component of diet among the people of south western Nigeria. Keywords: Nutrition, insects, Nigeria

SSR marker based DNA fingerprinting and diversity study in rice (Oryza sativa. L)

Abstract: The genetic diversity and DNA fingerprinting of 15 elite rice genotypes using 30 SSR primers on chromosome numbers 7-12 was investigated. The results revealed that all the primers showed distinct polymorphism among the cultivars studied indicating the robust nature of microsatellites in revealing polymorphism. Cluster analysis grouped the rice genotypes into 10 classes in which japonica types DH-1 (Azucena) and Moroborekan clustered separately from indica types. Principal component analysis was done to visualize genetic relationships among the elite breeding lines. The results were similar to UPGMA results. Based on this study, the larger range of similarity values for related cultivars using microsatellites provides greater confidence for the assessment of genetic diversity and relationships. The information obtained from the DNA fingerprinting studies helps to distinctly identify and characterize 9 varieties using 18 different RM primers. This information can be used in background selections during backcross breeding programs. Key words: PCR, polymorphism, DNA fingerprinting, dendogram.

Microbial growth and substrate utilization kinetics

Abstract: Microbial growth on and utilization of environmental contaminants as substrates have been studied by many researchers. Most times, substrate utilization results in removal of chemical contaminant, increase in microbial biomass and subsequent biodegradation of the contaminant. These are all aimed at detoxification of the environmental pollutants. Several microbial growth and biodegradation kinetic models have been developed, proposed and used in bioremediation schemes. Some of these models include Monod’s, Andrews, Bungay’s weighted model, general substrate inhibition models (GSIM) and sum kinetic models. Most research on microbial potentials to degrade chemical pollutants has been performed on a laboratory scale. There is a need to extend such studies to pilot scale as well as to full-scale field applications. Key words: Microbial growth, substrate utilization, biodegradation, kinetics, detoxification, organic contaminants, models, environmental pollutants.

Chemical composition and insecticidal properties of the underutilized Jatropha curcas seed oil

Abstract: The chemical composition and insecticidal activity of Jatropha curcas L. seed were evaluated using standard techniques. The oil content of the seed is high (66.4%). Triacylglycenol was the dominant lipid species, while the major triacyglycerol was 1,2-Dioleoyl-3-linoleoyl-rac-glycerol. Linolenic acid was the dominant fatty acid in the oil. Physico-chemical properties of the oil indicated that the acid value, fee fatty acids, peroxide value and iodine value were high. Ten seterols and thirteen tritepene alcohol was identified in the unsaponifiable fraction of the oil. Jatropha seed oil at various serial dilution ranging from 0% to 2% (v/w) at 0.5% intervals were evaluated for anti-ovipositional activity and long-term protective ability of treated cowpeas against the seed beetle Callosobruchus maculatus. The oil significantly (P l 0.05) reduced oviposition by C. maculatus in no-choice test in all the concentrations tested. The number of eggs laid by the seed beetle reduced from an average of 54. 33 +/- 3.53 in the control to only 4.00 +/- 1.53 in 2% oil-treated seeds. There was no adult emergency in all the oil. However in choice- tested seed, 6.67 +/- 1.33 eggs were laid in cultures treated with 2% oil while 21.67 +/- 1.45 were laid in control cultures. In dual-choice tests, oviposition was significantly reduced at all the oil concentration evaluated. J. Curcas oil also offers a 12-week protection for treated seeds since there were neither seed damage nor adult emergency in treated cowpea seeds. The results of this study suggest J. curcas has antioviposition and ovicidal effects on C. maculatus therefore making it a vaiable candidate for incorporation into pest control program of gain legumes.

Bioprospecting and antifungal potential of chitinolytic microorganisms

Abstract: Fungal plant diseases are one of the major concerns to agricultural food production world wide. Soil borne pathogenic fungi such as Pythium, Fusarium, Rhizoctonia and Phytopthora attack most of the economically important crop plants (either through seed root before germination or seedling after germination) resulting in loss of billions of dollars. Moreover, the management of chitinous waste is also pressing need today. Mycolytic enzymes (chitinases, proteases and glucanase) producing microorganisms may help in solving these problems. These microorganisms have ability to lyse the fungal cell wall and also have the potential to manage the chitinous waste by producing chitinases. Many chitinolytic microorganisms have potential to control fungal plant pathogens but they are not fully successful in all the cases due to different geological and environmental conditions. Thus, bioprospecting to find novel, highly chitinolytic microorganisms which help in developing potential biocontrol agent. Furthermore, to increase the survivability of biocontrol agents, a formulation may also be necessary. This review is focused on the progress of chitinase genes, chitinolytic microorganisms and their diversity as well as formulation of chitinolytic producers which have the potential to control fungal plant pathogens

Nutritional potentials of some tropical vegetable leaf meals: chemical characterization and functional properties

Abstract: Three tropical vegetable species (Talium triangulare, Amaranthus cruentus and Telfairia occidentalis) were selected based on their availability and agronomic desirability. The freshly harvested vegetable leaves were subjected to 2 processing techniques (shredding and sundrying) before milling into the vegetable leaf meals (VLMs). The crude protein ranged from 19.9+1.8 to 35.1+1.7. The crude fibre ranged from 8.8+3.1 to 12.7+4.2. Ether extract (fat) had a wide range of 5.4+3.2 to 29.2+2.1. Ash contents had a range of 10.9+6.2 to 19.4+3.0. The nitrogen free extract ranged from 19.7+0.3 to as high as 43.5+0.7. Gross energy values had a range of 251.5MJKg-1 to 383.2MJKg-1. The mineral contents of the air-dried VLMs indicated that Ca, Mg, Na, K are the most abundant minerals with values as high as 2.0, 2.5, 7.1 and 4.8gkg-1DM for Ca, Mg, Na and K respectively in some samples analysed. The amino acid profiles of the VLMs indicated favourable nutritional balance except for lysine and methinone which appear marginal. The Water Absorption Capacity (WAC), Fat Absorption Capacity (FAC), Fat Emulsion Capacity (FEC) and Emulsion Stability (ES) were similar for the 3 VLMs. The values obtained for Foaming Capacity, Least Gelation Concentration and Foaming Stability after 30 minutes for the 3 VLMs were also similar. The protein solubility curves of all VLMs were similar at both alkaline and acid media with minimum solubility (isoelectric point) at between pH 4 and 5 for the VLMs. Keywords: Vegetable leaf meals, nutritional potentials, amino acid profile

Bacteriocins and lactic acid bacteria - a minireview

Abstract: Fermentation of various foods by lactic acid bacteria (LAB) is one of the oldest forms of biopreservation practised by mankind. Bacterial antagonism has been recognized for over a century but in recent years this phenomenon has received more scientific attention, particulary in the use of various strains of lactic acid bacteria. One important attribute of LAB is their ability to produce antimicrobicrobial compounds called bacteriocin. In recent years, interest in the compounds has grown substantially due to their potential usefulness as natural substitute for chemical food preservatives in the production of foods with enhanced shelf life and/or safety. This balance is achived by its inhibitory effect upon the harmful pathogenic microorganisms. This paper presents some background on the scientific research about lactic acid bacteria as probiotics and their bacteriocins for healthy nutrition of fermented food. Probiotics had been of interest in the promotion of good health in animals and man. Some of the positive effects of probiotics are: growth promotion of farm animals, protection of host from intestinal infections, alleviation of lactose intolerance, relief of constipation, anticarcinogenic effect, anticholesterolaemic effects, nutrient synthesis and bioavailability, prevention of genital and urinary tract infections and imunostimulatory effects.

Nutrient effects on production of cellulolytic enzymes by Aspergillus niger

Abstract: The production of cellulase (filter paper activity, endoglucanase and )-glucosidase) by Aspergillus niger on three media in liquid shake culture was compared. The culture filtrate of this organism exhibited relatively highest activity of all three enzymes and extracellular protein content at 7-day interval during the course of its growth on Czapek-Dox medium supplemented with 1.0% (w/v) cellulose. Urea as a nitrogen source and pH 5.0 were found to be optimal for growth and cellulase production by A.niger . Among various soluble organic carbon sources and lignocelluloses tested in this study, carboxymethylcellulose and sawdust at 1% supported maximum production of all three enzymes by A.niger . Keywords: Aspergillus niger , cellulase activity, nutrients, 6-glucosidase

Antimicrobial activities of medicinal plants used in folklore remedies in south-western

Abstract: In south-western part of Nigeria Psidium guajava and Mangifera indica are commonly used for herbal preparations in the treatment of toothache, gastrointestinal disorders, dynsentery, diarrhoea, sore gums and sore throats. This has, therefore, led to the investigation of the antimicrobial activities of methanolic extracts of P. guajava and M. indica. Fifteen different bacterial isolates comprising of both Gram negative and Gram positive organisms were used. The results show that P. guajava and M. indica extracts exhibited antimicrobial activities at a concentration of 20 mg/ml. The zones of inhibition exhibited by P. guajava extract ranged between 12 mm and 30 mm while that of M. indica varied between 11 and 28 mm. The minimum inhibitory concentration (MIC) exhibited by P. guajava extract against the tested organisms ranged between 0.313 and 0.625 mg/ml. On the other hand MIC exhibited by M. indica extract varied between 1.25 and 10.0 mg/ml. Overall, P. guajava extract show more antimicrobial activity than M. indica extract against tested organisms.

Occurrence and functioning of phosphate solubilizing microorganisms from oil palm tree (Elaeis guineensis) rhizosphere in Cameroon

Abstract: Phosphorus replenishment, particularly in smallholder agriculture, remains a challenge as it is mainly fertilizer dependent. While the use of soluble mineral phosphate fertilizers is the obvious best means to combat phosphate deficiency in Cameroon, their use is limited by their high cost and availability at farmer’s level. This study was aimed at maintaining the fertility of Cameroon soils by biological means, in order to improve agricultural production, using low inputs technology. Isolates were obtained from oil palm tree (Elaeis guineensis) root fragments and rhizospheric soils and their activity in mobilizing phosphate from insoluble sources was evaluated on agar plates and liquid culture media containing sparingly soluble phosphates. At the end of incubation time, it appeared that, phosphate solubilization resulted from a combined effect of pH decrease of the media and organic acids production. Furthermore, each of the tested isolates was able to produce at least one of the most important organic acids such as citrate, malate and tartrate. Among the ten isolates tested, three were identified as Pseudomonas fluorescens and would be considered as potential biofertilizers.

Textile effluent biodegradation potentials of textile effluent-adapted and non-adapted bacteria

Abstract: Environmental pollution has been recognized as one of the major problems of the modern world. The increasing demand for water and the dwindling supply has made the treatment and reuse of industrial effluents an attractive option. Textile effluents are of concern because they colour the drains and ultimately the water bodies. They also diminish the water quality. The ability of microorganisms to degrade and metabolize a wide variety of compounds has been recognized and exploited in various biotreatment processes. This study investigated the potential of bacteria isolated from textile industries wastewater and drains (textile effluent adapted bacteria) and isolates from a municipal landfill (effluent non-adapted bacteria). We discovered effluent adapted strains of Acinetobacter, Bacillus and Legionella with potentials for colour removal and strains of Acinetobacter, Bacillus and Pseudomonas with chemical oxygen demand (COD) removal activities. Only strains of Bacillus with potentials for use in colour and COD removal were isolated from the landfill. Plasmid screening did not reveal the presence of plasmids in the isolates. Thus the involvement of extra-chromosomal genes is not suggested. In conclusion, as a preliminary step in the development of textile effluent biotreatment using indigenous microbes, we have discovered some strains with potency to decolourize and/or remove COD.

Quality characteristics of bread produced from composite flours of wheat, plantain and soybeans

Abstract: The use of soy flour (SF) and plantain flour (PF) substitution in wheat flour (WF), from 0 to 15% each, for the production of bread was investigated. The proximate analysis, sensory evaluation and aerobic plate count (APC) of the bread samples were determined. The crude protein, crude fiber, ether extract and ash contents of the soy supplemented breads (SSBs) increased with progressive increase in the proportion of soy flour, with the 15% SSB having highest values of 8.39, 0.14, 2.46 and 1.17%, respectively, while lowest values were recorded for the whole wheat bread (WWB). The carbohydrate content was observed to decrease with corresponding increase in the percentage of soy flour in SSBs. The sensory evaluation shows that no significant differences were observed between the WWB and the 5% SSB in the sensory attributes of aroma, internal texture, taste and general acceptability (p<0.05), but differences were significant in crust, shape and appearance. The crude protein of the plantain supplemented breads (PSBs) and the WWB ranges between 6.88 and 7.01%, with the WWB recording the highest value. The ash content increased with progressive increase in the proportion of the PF, the highest value (0.95%) was recorded for the 15% PSB. There were no significant differences (p<0.05) between the WWB and the PSBs up to 10% PF substitution in all the sensory attributes tested; crust, taste, aroma, shape, internal texture, appearance and general acceptability. Hence the PSBs had comparable sensory and nutritional qualities to the WWB, while the SSBs had higher proteins contents than the latter. However the WWB had highest Hedonic mean scores in all the sensory attributes tested.

In vitro production of growth regulators and phosphatase activity by phosphate solubilizing bacteria

Abstract: Crops absorb phosphorous in the form of soluble orthophosphate ion The solubility of phosphate is inhibited by the presence of iron and aluminium in acidic soils and calcium in neutral and alkaline soils This leads to fixation of phosphorous, making it not available to crop plants The phosphate solubilizing bacteria (phosphobacteria) secretes some kinds of organic acids which act on insoluble phosphates and convert the same into soluble form, thus providing phosphorous to plant An experiment was conducted to enumerate the population density of phosphobacteria in the rhizosphere soils of brinjal, chilly, cotton, green grain, groundnut, maize, paddy, ragi, sorghum and turmeric using Ketznelson and Bose medium following dilution plate technique Efforts have been made to isolate phosphobacteria from these soils and isolated strains were inoculated in specific media containing specific substrates to produce growth regulating substances such as IAA and GA3 and phosphatase enzyme The result showed that the population levels of phosphobacteria were higher in the rhizosphere soil of groundnut plant Further, all the strains of phosphobacteria were able to produce phytohormones and phosphatase enzyme under in vitro conditions

Amylase production by Penicillium fellutanum isolated from mangrove rhizosphere soil

Abstract: The effects of pH, temperature, incubation time, salinity, sources of carbon and nitrogen were tested in submerged fermentation process in production of �-amylase by Penicillium fellutanum isolated from coastal mangrove soil. The production medium without addition of seawater and with provision of maltose as carbon source, peptone as nitrogen source, incubated for 96 h, maintained with pH of 6.5 at 30 o C, was found optimal for production of �-amylase by P. fellutanum.

Evaluation of the antimicrobial activity of saponins extract of Sorghum Bicolor L. Moench

Abstract: The n-butanol purified saponin extract of sorghum bicolor were screened for anti-bacterial activity against three pathogenic microbes; Escherichia coli, Staphylococcus aureus and Candida albicans. The extract inhibited the growth of the S. aureus. It was concluded that the saponins have inhibitory effect on gram-positive organism but not on gram negative organism and the fungi.

Antifungal effects of two tropical plant leaf extracts (Ocimum gratissimum and Aframomum melegueta) on postharvest yam (Dioscorea spp.) rot

Abstract: Effects of leaf extracts of Ocimum gratissimum and Aframomum melegueta on spore germination and mycelial reduction of the most occurring fungal pathogen causing soft rot of yam tuber were investigated. Fungi isolated from rotted yams were Aspergillus niger, A. flavus, Fusarium oxsporium Rhizopus stolonifer, Botryodiplodia theobromae and Penicillium chrysogenum. The leaf extracts with ethanol extraction were most effective followed by cold-water and hot water extraction. The fungicidal activity with Ocimum gratissimum leaf extracts was more effective. In vitro inoculation of fresh yam with A. niger, A. flavus and F. oxsporum at room temperature for 3 months showed typical rot symptoms characteristic of the disease. The significance of these findings is discussed in relation to plant chemical or non-chemical means of disease control on yams in Africa.

Antimicrobial activity of Rauvolfia tetraphylla and Physalis minima leaf and callus extracts

Abstract: The in vitro antimicrobial activity of Rauvolfia tetraphylla and Physalis minima leaf and callus extracts were studied against selected pathogenic fungi and bacteria, following broth dilution assay. Leaves and calli were extracted using absolute alcohol, benzene, chloroform, methanol and petroleum ether. Among the five solvents used, leaf and callus extracted in chloroform of both the plants were found to be more effective against pathogenic bacteria and fungi, where the minimum inhibitory concentration (MIC) ranged between 0.25 to 6 mg/ml. Absolute alcohol extracts showed MIC of 0.25 to 4 mg/ml for bacteria, whereas for fungi it ranged from 0.25 to 100 mg/ml. Extracts of benzene and petroleum ether were ineffective in inhibiting the bacterial and fungal growth or showed poor inhibition. Methanol extract showed MIC of 0.25 to 100 mg/ml against bacterial pathogens and 0.5 to 100 mg/ml against fungal pathogens. The antimicrobial activities of these two indigenous medicinal plants were discussed in the present paper.

Antibacterial susceptibility of some urinary tract pathogens to commonly used antibiotics

Abstract: Urinary tract infection represents one of the most common diseases encountered in medical practice today and occurring from the neonate to the geriatric age group. Despite the widespread availability of antibiotics, it remains the most common bacterial infection in the human being. A total of 174 urine samples were analyzed for isolation and identification, 68 found to be significant bacteriuria with Escherichia coli (59%), followed by Pseudomonas aeruginosa (15%), Klebsiella pneumoniae (10%), Proteus mirabilis (9%), Staphylococcus aureus (6%) and Citrobacter freundii (1%). The urinary tract infections were found to most frequently in female (63%) than male (37%). The isolated uropathogens showed resistant to ampicillin (87%), co-trimoxazole (91%), nalidixic acid (88%) and sensitive to nitrofurantoin (52%), cephotaxime (54%) and norfloxacin (71%).

Hygienic status assessment of dish washing waters, utensils, hands and pieces of money from street food processing sites in Ouagadougou (Burkina Faso)

Abstract: During investigations on street food vendors’ materials, seventy samples of three types of dish washing water (E1, E2, E3), eighty-five pieces of money, eighty utensils were collected for microbiological assessment. Hands microbiological status of one hundred twenty-five consumers and seventy sellers were also assessed. The analysis revealed that 100% of E1 washing waters were very impure, while, 44.5% of second washing water (E2) were impure, 44.5% very impure and 11% acceptable. 45.45% of E3 washing water were acceptable, 27.27% impure and 27.27% very impure. The spoons and the dinner plates were sometimes contaminated with unacceptable levels (above 102) of different bacteria such as, coliforms and Staphylococcus aureus (P
0.05). Knives microbiological examination revealed presence of numerous bacteria (8.6 x 105 cfu/knife) such as coliforms, S. Aureus, Salmonella and Shigella. Pieces of money analysis revealed presence of coliforms and S. aureus. These data showing pathogen bacteria in food vending sites indicates hygiene monitoring failure.

Influence of poultry manure and NPK fertilizer on yield and yield components of crops under different cropping systems in south west Nigeria

Abstract: Field experiments were conducted in two villages (Oniyo and Moloko Ashipa) representing two agro ecologies in the south west area of Nigeria during 2000 and 2001 cropping seasons. The objective was to determine the effects of NPK fertilizer and poultry manure on the yield and yield components in cassava/maize/melon systems. The factors were (1) cropping systems: cassava/maize/melon, sole cassava, sole maize and sole melon; and (2) fertilizers: no fertilizer, NPK 15-15-15 (400 kg/ha), poultry manure (5 t/ha), 2.5 t/ha poultry manure + 200 kg/ha NPK 15-15-15 and mineral fertilizer (NPK 15-15-15). Intercropping had no significant effect on cassava root yield but it reduced maize and melon seed yield compared to sole cropping. Land equivalent ratio (LER) values were however higher under intercropping than sole cropping. Crop yields were statistically the same under NPK alone and NPK + poultry manure but significantly higher than both poultry manure alone and control in both locations

Insecticidal activity of four medicinal plant extracts against Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae)

Abstract: Methanol extracts from four medicinal plants, Peganum harmala (Zygophyllaceae), Ajuga iva (Labiateae), Aristolochia baetica (Aristolochiaceae) and Raphanus raphanistrum (Brassicaceae) were studied for their insecticidal effects on the stored grain pest Tribolium castaneum (Herbst). Response varied with plant species. Larvae growth was significantly inhibited when they were fed with extracts incorporated into the diet. Good insecticidal activity against T. castaneum larvae and adults was achieved with extract of P. harmala seeds, followed by extract of A. iva, Ari. baetica and R. raphanistrum aerial parts. The extracts of the four plants disrupted the developmental cycle of the insect. Extracts of P. harmala, A. iva and Ari. baetica inhibited F1 progeny production. These naturally occurring plant extracts could be useful for managing populations of T. castaneum.

Simulated flooding and drought effects on germination, growth, and yield parameters of sesame (Sesamum indicum L.)

Abstract: The effects of drought on germination of sesame seeds (Sesamum indicum L.) also known as benniseed were simulated in the laboratory using varying concentrations of sodium chloride, glucose and polyethylene glycol at 0 ‐ 0.50 MPa water potential. Higher osmotic conditions (0.25 ‐ 0.50 MPa) significantly reduced the percentage germination, radical and shoot development. The ability of the three chemicals to reduce germination and seedling development in sesame was of the order: polyethylene glycol < glucose < sodium chloride. Different irrigation regimes of water were used to induce flooding and drought effects on plants cultivated in pots in a green house. Both flooding and drought resulted in stunted growth, reduced dry matter, number of leaves per plant and seed yield per plant. Prolonged flooding reduced maturity time, and induced chlorosis and floral abortion. The growth and seed yield of sesame are adversely affected by continuous flooding and severe drought.

Is Vernonia amygdalina hepatotoxic or hepatoprotective? Response from biochemical and toxicity studies in rats

Abstract: The effects of various concentrations of aqueous extract of Vernonia amygdalina leaves on some biochemical indices of liver function were investigated in albino Wistar rats. Acute toxicity tests of the extract gave an LD50 of 500 mg/kg. Phytochemical analysis of the plant material showed that anthracene glycosides, steroids, flavonoids, proteins, carbohydrates, reducing sugars, saponins and tannins were present. Liver function tests revealed that the activity of aspartate aminotransferase (AST) increased significantly (p 0.05) increase in both alanine aminotransferase and alkaline phosphatase activities for all the concentrations administered. Also the increase in mean values of conjugated and unconjugated bilirubin for all the concentrations administered were not statistically significant (p>0.05). The results, therefore, strongly suggest that V. amygdalina leaf extract is not hepatotoxic in rats. The findings are of nutritional, clinical and veterinary relevance considering the diverse applications of the plant in almost all African populations.

Antimicrobial activity of Solanum tomentosum

Abstract: Acetone, methanol and water extracts from the leaves of Solanum tomentosum were investigated for their antimicrobial activities. Growth inhibition was determined using agar dilution assays against ten selected bacterial and three fungal species. Acetone and methanol extracts were active against the Gram positive and Gram negative bacteria at a concentration of 5 mg/ml. None of the extracts inhibited the growth of Staphylococcus aureus, Escherichia coli, Klebsiella pneumonae and Penicillium notatum. The activities of the extracts on the test fungi were generally low. Methanol extracts was particularly suppressive to the growth of fungi with inhibitory percentage ranging from 47.22 to 50.56% on Aspergillus niger and Fusarium oxysporum.