Showing papers in "African Journal of Biotechnology in 2007"

Preliminary phytochemical and antimicrobial screening of 50 medicinal plants from Nigeria

Abstract: Ethanolic extracts of 50 plant species were screened for their antimicrobial activity against Bacillus subtilis, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans. The results indicated that of the 50 plant extracts, 28 plant extracts inhibited the growth of one or more test pathogens. Four plant extracts showed a broad spectrum of antimicrobial activity. Phytochemical investigation revealed the presence of tannins, saponins, alkaloids, glycosides, flavonoids and essential oils.

Inflammation: the foundation of diseases and disorders. A review of phytomedicines of South African origin used to treat pain and inflammatory conditions.

Abstract: Great interest in herbal medicine as a potential source of phytopharmaceuticals has created the need to review common factors responsible for major diseases and body disorders. This review shows one such common factor in inflammation and the role herbal medicine can play. Traditional medicinal herbal remedies in the southern African region have long been used to treat various pain- or inflammation-related symptoms. Although the precise mechanisms of action of many herbal drugs have yet to be determined, some of them have been shown to exert anti-inflammatory and/or antioxidant effects in a variety of cells in the human and animal bodies. There is increasing evidence to indicate that both peripheral and central nervous system cells play a prominent role in the chronic inflammatory responses in the body system and anti-inflammatory herbal medicine and its constituents are being proved to be a potent protector against various pro-inflammatory mediators in diseases and disorders. These mediators have therefore been suspected of being the functional basis of diseases and disorders. The structural diversity of these medicinal herbs makes them a valuable source of novel lead compounds against the therapeutic molecular targets, cytokines and mediators, that have been newly discovered by the platforms of genomics, proteomics, metabolomics and highthroughput technologies. This article reviews the basic mechanisms of inflammation and the potential of 123 southern African plant species to be effective as chronic inflammatory disease preventive agents. With one third of these species there are no indications of the chemical composition, indicating possible subjects for further research.

Nutritional and chemical value of Amaranthus hybridus L. leaves from Afikpo, Nigeria

Abstract: The nutritional and chemical value of Amaranthus hybridus were investigated using standard analytical methods in order to assess the numerous potential of the plant leaves. The Proximate analysis showed the percentage moisture content, ash content, crude protein, crude lipid, crude fibre and carbohydrate of the leaves as 84.48, 13.80, 17.92, 4.62, 8.61 and 52.18%, respectively while its calorific value is 268.92 Kcal/100 g. Elemental analysis in mg/100 g (DW) indicated that the leaves contained sodium (7.43), potassium (54.20), calcium (44.15), Magnesium (231.22), Iron (13.58), Zinc (3.80) and phosphorus (34.91). The vitamin composition of the leaves in mg/100 g (DW) was β-carotene (3.29), thiamine (2.75), riboflavin (4.24), niacin (1.54), pyridoxine (2.33), ascorbic acids (25.40) and α-tocopherol (0.50). Seventeen amino acids (isoleucine, leucine, lysine, methionine, cysteine, phenylalmine, tyrosine, threonine, valine, alanine, arginine, aspartic acid, glutamic acid, glycine, histidine, proline and serine) were detected. The chemical composition in mg/100 g (DW) for alkaloid, flavonoid, saponin, tannins, phenols, hydrocyanic acid and phytic acid were 3.54, 0.83, 1.68, 0.49, 0.35, 16.99 and 1.32, respectively. Comparing the nutrient and chemical constituents with recommended dietary allowance (RDA) values, the results reveal that the leaves contain an appreciable amount of nutrients, minerals, vitamins, amino acids and phytochemicals and low levels of toxicants. Key words: Amaranthus hybridus L. leaves, diet, minerals, vitamins, amino acids, phytochemicals.

Antifungal and antibacterial activities of the ethanolic and aqueous extract of Kigelia africana (Bignoniaceae) stem bark

Abstract: Studies on the antibacterial and antifungal activities of the stem bark of Kigelia africana, (LAM). Benth (Family: Bignoniaceae), a medicinal plant used in South, Central and West Africa for the treatment of various ailments and infection was carried out using agar diffusion technique. The results revealed that the crude ethanolic extract exhibited antibacterial and antifungal activities against Staphylococccus aureus and Candida albicans with zones of inhibition measuring 15.0±0.95 and 20.75±4.6mm respectively. The aqueous extract exhibited no antibacterial or antifungal activity. The minimum inhibitory concentration for the extract was 6.25 ± 1.07 mg/ml for S. aureus and 7.92 ± 1.52 mg/ml for C. albicans. The ethanolic extract was also compared with various standards; Ampicillin, Gentamicin, Ceftriaxone and Ciprofloxacin. The ethanolic extract (20mg/ml) produced similar zone of inhibition with 25ig disc of amoxicillin.

Antioxidant capacity of different types of tea products

Abstract: In the present study, twelve different types of commercial tea samples were assayed to determine their phenolic composition and antioxidant activity. Reverse phase high performance liquid chromatography using a binary gradient system was used for the identification and quantification of individual catechins. Subsequently, total phenolic content was determined spectrophotometrically according to the Folin-ciocalteus method. Total theaflavins and thearubigins were also determined. The radical scavenging behavior of the polyphenols on 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) was also studied spectrophotometrically. The results showed that total polyphenols, total catechins and antioxidant activity were significantly (P<0.05) different in the commercial tea samples. Green tea had the highest levels of catechins, total polyphenols and total antioxidant activity. White tea (silvery tip) a rare specialty type of tea was not significantly different from green tea. Statistical analysis showed an essential catechin content influence of the tea extracts on antioxidant activity. Epigallocatechin gallate (EGCG) was the most potent catechin and the most potent in antioxidant activity (r = 0.989***). Epigallocatechin (EGC) (r = 0.787, P<0.001), epicatechin (EC) + catechin (+C) and epicatechigallate (ECG) also showed significant (P<0.05) antioxidant activity. Black tea contained high levels of theaflavins and thearubigins, which accounted for most of the antioxidant potential in this type of tea product (r = 0.930*** and r = 0.930*** respectively). These results suggest that conversion of catechins during black tea processing did not affect the free-radical potency of black tea. Gallic acid (GA) also showed significant(r = 0.530*) contribution to the antioxidant activity in black tea. Green, black and white tea products processed from Kenyan tea cultivars originally selected for black tea had significantly (P<0.05) higher antioxidant activity than green tea processed from tea cultivars from Japan and China. These results seem to suggest that the cultivar type is critical in determining the antioxidant potency of tea product and that black teas processed from suitable cultivars could be potent in antioxidant activity when compared to green teas.

Chemical composition and functional properties of flour produced from two varieties of tigernut (Cyperus esculentus)

Abstract: The chemical composition and functional properties of flour produced from two varieties (yellow and brown) of tigernut (Cyperus esculentus) seeds were studied. The seeds were obtained in dried form, sorted, wet cleaned, dried, milled and sieved to produce flour. The flours were tagged YTF and BTF for yellow and brown varieties, respectively. The protein contents of YTF and BTF were 7.15 and 9.70%, respectively. BTF has higher fat, ash, potassium, magnesium, manganese and iron contents than YTF. On the other hand, YTF has higher carbohydrate, crude fibre, calcium, sodium and copper contents. The zinc and copper levels were low in both flours (0.01 - 0.02 mg/100 g). A low bulk density (0.55 - 0.62 g/cm3), setback viscosity (6.58 - 13.75 RVU) and breakdown viscosity (0.58 - 1.50 RVU) were recorded for the flours.

Breeding and disseminating quality protein maize (QPM) for Africa

Abstract: Quality protein maize (QPM) describes a range of maize cultivars with twice the content of limiting amino acids lysine and tryptophan compared with conventional maize, and has been developed to help reduce human malnutrition in areas where protein deficiency is prevalent and where maize is the major protein source in the diet, as in various parts of Sub-Saharan Africa (SSA). The International Maize and Wheat Improvement Center (CIMMYT), in collaboration with the International Institute of Tropical Agriculture (IITA) and the National Agricultural Research Systems (NARS) in 17 countries of SSA, has developed a broad range of QPM cultivars responding to the needs of different countries and agroecological zones. Commercial QPM seed is currently available in all collaborating countries and, based on average 2003-2005 seed production, approximately 200,000 hectares of land are being planted to QPM cultivars. Key words: Quality protein maize, opaque-2, en-modifiers, aa-modifiers, genetics, plant breeding, dissemination, impact assessment, human nutrition.

Cassava wastes: treatment options and value addition alternatives.

Abstract: Value addition of cassava and cassava wastes is necessitated by rapid post-harvest spoilage, deterioration, low protein content and environmental pollution caused by the effluent and the other associated wastes that poses aesthetic nuisance. Biogas plants of all sizes and varying levels of technical sophistication not only recover the energy contained in cassava wastes but also eliminate most of the animal and human health problems associated with contamination. Studies have shown the technical feasibility and nutritional desirability of converting carbohydrates and their residues into products containing a large amount of protein by means of microorganisms. Wastes transformation offers the possibility of creating marketable value-added products. There exists a great potential in the use of microorganisms such as fungi for the production of high quality feedstuffs from the abundantly available agro-industrial wastes, particularly carbohydrate residues. Cassava wastes can be processed and converted into value-added components such as methane (biogas), pig meat, ethanol, surfactant and fertilizer etc. Attention is now focused on the by-products of the anaerobic decomposition of the waste that takes place in a biodigester, which are the liquid fraction called biol and the solid fraction or biosol, which are excellent fertilizers for a variety of crops. The present review addresses the progress that has been made in each of these aspects with emphasis on the advantages of biol and biosol fertilizers. Key words: Carbohydrate residue, waste transformation, biofertilizers.

The challenges of overcoming antibiotic resistance: Plant extracts as potential sources of antimicrobial and resistance modifying agents

Abstract: The problem of antibiotic resistance, which has limited the use of cheap and old antibiotics, has necessitated the need for a continued search for new antimicrobial compounds. Understanding the mechanisms of resistance is important in the development of strategies to solving the problem. Active efflux of drugs, alteration of target sites and enzymatic degradations are the strategies by which pathogenic bacteria acquire or develop intrinsic resistance to antibiotics. Multi-drug resistance (MDR) pumps, capable of recognizing and expelling a variety of structurally unrelated compounds from the bacterial cell and conferring resistance to a wide range of antibiotics have since been characterized in many gram positive and gram negative pathogens like Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and, more recently, in mycobacteria. The ability of some chemical compounds (called MDR inhibitors or resistance modifying agents) to modify the resistance phenotype in bacteria by working synergistically with antibiotics in vitro has since been observed. The search for such compounds which can be combined with antibiotics in the treatment of drug resistant infections may be an alternative to overcoming the problem of resistance in bacteria. Crude extracts of medicinal plants stand out as veritable sources of potential resistance modifying agents and the African biosphere promises to be a potential source of such compounds owing to its rich plant species diversity.

Isolation and characterization of engine oil degrading indigenous microrganisms in Kwazulu-Natal, South Africa

Abstract: As the usage of petroleum hydrocarbon products increases, soil contamination with diesel and engine oils is becoming one of the major environmental problems. To investigate the countermeasure to remediate soils contaminated with oils, bioremediation provide an effective and efficient strategy to speed up the clean-up processes. Three bacterial isolates capable of utilizing used engine-oil as a carbon source were isolated from contaminated soils using the enrichment technique. Three isolates were identified as Flavobacterium sp., Acinetobacterium calcoaceticum and Pseudomonas aeruginosa based on biochemical tests and 16S rRNA sequencing. The gavimetric analysis revealed that A. calcoaceticum and a consortium of the isolates were capable of utilizing 80 and 90% of used engine oil, respectively, under laboratory conditions at 30°C and 160 rpm with Bushnell-Haas media in a 4 week period. An increase in oil degradation is correlated to an increase in cell number indicating that the bacterial isolates were responsible for the oil degradation. All isolates were capable of degrading the nparaffin up to 80% in a 2 week period. The optimal temperatures at which biodegradation occurred at 30–37°C. The preference of nitrogen sources and minimal salts were different for different bacterial isolates. The results obtained demonstrate the potential for oil bioremediation of these isolates in situ and/or ex situ.

Biodiesel generation from oleaginous yeast Rhodotorula glutinis with xylose assimilating capacity

Abstract: This study explored a strategy to convert agricultural and forestry residues into microbial lipid, which could be further transformed into biodiesel. Among the 250 yeast strains screened for xylose assimilating capacity, eight oleaginous yeasts were selected by Sudan Black B test. The lipid content of these 8 strains was determined by soxhlet extraction method. One strain (T216) was found to produce lipids up to 36.6%, and it was identified as Rhodotorula glutinis. The optimal fermentation conditions were obtained as follows: glucose as carbon source 100 g/L; yeast extract and peptone as nitrogen sources at, respectively, 8 and 3 g/L; initial pH of 5.0; inoculation volume of 5%; temperature at 28oC, shaking speed of 180 r/min, cultivated for 96 h. Under these conditions, R. glutinis accumulated lipids up to 49.25% on a cellular biomass basis and the corresponding lipid productivity reached 14.66 g/L. Experiments with a 5-L bioreactor under the optimal culture conditions showed that R. glutinis accumulated lipids up to 60.69%, resulting in 23.41 g/L in lipid productivity. More encouraging results were observed for the lipid production with alternative carbon sources. Corn stalk and Populus euramevicana leaves hydrolysate could be used to substitute glucose. Chemical analysis indicated that biodiesel obtained by transesterification possessed similar composition to that from vegetable oil, one of the widely used feedstock for biodiesel.

Antibacterial effects of Balanites aegyptiaca L. Drel. and Moringa oleifera Lam. on Salmonella typhi

Abstract: The aqueous and organic leaves extracts of Balanites aegyptiaca and Moringa oleifera traditionally used for the treatment of infectious disease were tested for their activity against Salmonella typhi isolated from blood clot culture using the disc diffusion method. Extracts of B. aegyptiaca demonstrated higher activity (16 mm zone of inhibition) than those of Moringa oleifera (8 mm zone of inhibition) at 100 mg/ml. Of the three solvents used, ethanolic extracts of both plants demonstrated the highest activity, while the aqueous extracts showed the least activity at 100 mg/ml. The activities of these plant extracts were comparable to those of antibiotics, ciprofloxacin, cotrimoxazole and chloramphenicol, commonly used for treating typhoid fever. The antibacterial activity appears to increase when extracts of the two plants were used in combination at 100 mg/ml each (18 mm zone of inhibition). Preliminary phytochemical screening showed that both plant extracts contains saponins, tannins and phenols while only M. oleifera possesses alkaloids and B. aegyptiaca possesses anthraquinones. The antibacterial activities of the extracts on S. typhi was reasonably stable when treated at 4, 30, 60 and 100oC for 1 h, however it reduces significantly when the pH was altered towards alkalinity.

Antibacterial activities of some marine algae from the Aegean Sea (Turkey)

Abstract: In this study, methanolic extracts of six marine algae belong to Rhodophyceae (Corallina officinalis), Phaeophyceae (Cystoseira barbata, Dictyota dichotoma,Halopteris filicina, Cladostephus spongiosus f. verticillatus) and Chlorophyceae (Ulva rigida) from the North Aegean Sea (Turkey) were studied for their antibacterial activity against pathogenic microbes, 3 gram positive (Staphylococcus aureus, Micrococcus luteus and Enterococcus faecalis) and 3 Gram negative (Escherichia coli, Enterobacter aerogenes and E. coli O157:H7) in vitro. Extracts of all the test marine algae except C. officinalis showed inhibition against S. aureus. On the other hand, highest inhibiton activity among all the extratcs was shown to E . aerogenes by C . officinalis. The extract from C. barbata has shown broader activity spectrum against all the test organisms. Key words: Aegean sea, antib In this study, methanolic extracts of six marine algae belong to Rhodophyceae (Corallina officinalis), Phaeophyceae (Cystoseira barbata, Dictyota dichotoma,Halopteris filicina, Cladostephus spongiosus f. verticillatus) and Chlorophyceae (Ulva rigida) from the North Aegean Sea (Turkey) were studied for their antibacterial activity against pathogenic microbes, 3 gram positive (Staphylococcus aureus, Micrococcus luteus and Enterococcus faecalis) and 3 Gram negative (Escherichia coli, Enterobacter aerogenes and E. coli O157:H7) in vitro. Extracts of all the test marine algae except C. officinalis showed inhibition against S. aureus. On the other hand, highest inhibiton activity among all the extratcs was shown to E . aerogenes by C . officinalis. The extract from C. barbata has shown broader activity spectrum against all the test organisms. Key words: Aegean sea, antibacter In this study, methanolic extracts of six marine algae belong to Rhodophyceae (Corallina officinalis), Phaeophyceae (Cystoseira barbata, Dictyota dichotoma,Halopteris filicina, Cladostephus spongiosus f. verticillatus) and Chlorophyceae (Ulva rigida) from the North Aegean Sea (Turkey) were studied for their antibacterial activity against pathogenic microbes, 3 gram positive (Staphylococcus aureus, Micrococcus luteus and Enterococcus faecalis) and 3 Gram negative (Escherichia coli, Enterobacter aerogenes and E. coli O157:H7) in vitro. Extracts of all the test marine algae except C. officinalis showed inhibition against S. aureus. On the other hand, highest inhibiton activity among all the extratcs was shown to E . aerogenes by C . officinalis. The extract from C. barbata has shown broader activity spectrum against all the test organisms. Key words: Aegean sea, antibacterial activity, Corallina officinalis, marine algae. ial activity, Corallina officinalis, marine algae. acterial activity, Corallina officinalis, marine algae.

Antibacterial activities and toxicological potentials of crude ethanolic extracts of Euphorbia hirta

Abstract: Leaves of Euphorbia hirta used in traditional medicine for the treatments of boils, wounds and control of diarrhoea and dysentery were extracted by maceration in ethanol. The agar diffusion method was used to determine the antibacterial activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi and Bacillus subtilis at different concentrations while toxicological studies was carried out through intraperitoneal injection of albino rat with varying concentrations of the extract. Antibacterial sensitivity test indicated that the extract inhibited the growth of S. aureus, E. coli, B. subtilis and P. aeruginosa to varying degrees while S. typhi was not affected. Minimum inhibitory concentration (MIC), of the extract against E. coli, S aureus, P. aeruginosa and B. subtilis were 58.09, 22.55, 57.64 and 74.61 mg/ml respectively. Hematological analyses revealed that there was no significant difference (p = 0.05) between the total red blood cells (RBC), white blood cells (WBC), hemoglobin (Hb) and mean corpuscular hemoglobin concentration (MCHC) values of the rats used as control and those treated with the different concentrations of the extract. Also, the erythrocyte sedimentation rate (ESR) and mean corpuscular volume (MCV) values were significantly different at certain concentrations of the extract administered which indicates that the plant extract is heamatologically not toxic to rats. The plant extract was found to contain tannins, alkaloids and flavonoids which may be responsible for its antimicrobial properties. The results justify the traditional use of the plant in the treatment of sores, boils, wounds and control of dysentery and diarrhoea.

Wastewater treatment plants as a source of microbial pathogens in receiving watersheds

Abstract: Wastewater treatment facilities have become sin quo non in ensuring the discharges of high quality wastewater effluents into receiving water bodies and consequence, a healthier environment. Due to massive worldwide increases in human population, water has been predicted to become one of the scarcest resources in the 21st century, and despite large advances in water and wastewater treatments, waterborne diseases still pose a major threat to public health worldwide. Several questions have been raised on the capacity of current wastewater treatment regimes to remove pathogens from wastewater with many waterborne diseases linked to supposedly treated water supplies. One of the major gaps in the knowledge of pathogenic microorganisms in wastewater is the lack of a thorough understanding of the survival and persistence of the different microbial types in different conditions and environments. This therefore brings to the fore the need for a thorough research into the movement and behavior of these microorganisms in wastewaters. In this review paper we give an overview of wastewater treatment practices with particular emphasis on the removal of microbial pathogens. Key words: Wastewater, treatment plants, microbial pathogens, watershed.

Chemical constituents and antioxidant activity of Alstonia boonei

Abstract: The chemical composition and some antioxidant indices of Alstonia boonei stem-bark extract were evaluated. A. boonei was found to contain important minerals like calcium, phosphorus, iron, sodium, potassium, and magnesium. Alkaloids, tannins, saponins, flavonoids and cardiac glycosides were among the phytochemicals detected together with the important vitamin, ascorbic acid. DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, total phenolic content and reducing power were 41.58 ± 1.43 %, 2.09 ± 0.04 mg/g gallic acid equivalent and 0.32 ± 0.01 respectively. Against the backdrop of the many medicinal uses of the plant, the results of the present work indicate that phytochemicals, other than phenolics, the mineral elements and vitamin C may be the critical factors in the medicinal effects of A. boonei.

Performance of wheat genotypes under osmotic stress at germination and early seedling growth stage

Abstract: Sixteen wheat genotypes including local varieties were tested in completely randomized design with three repeats. Data were recorded at four different moisture levels by using polyethylene glycol (PEG) 6000 on germination percentage, germination rate index, shoot length, root length, fresh weight of shoot, dry weight of shoot, fresh weight of root, dry weight of root, shoot/root ratio and analysed for significance. The genotypes differ significantly in response to the moisture stress. There were highly significant differences for all traits. PK-18199 gave the maximum germination percentage, germination rate index, shoot length root length, coleoptile length, fresh shoot weight, dry shoot weight, fresh root weight, dry root weight and root/shoot ratio under all four moisture stresses. PK-18175 showed maximum resistance against moisture stress while WAFAQ 2001 showed minimum resistance. AS-2002 and KC033 also gave the better performance under all four moisture levels for most of the traits at seedling stage. 99FJ03 gave maximum root/shoot length ratio while PK 18199 gave minimum value of root/shoot length ratio showing resistance against water stress.

Evaluation of antibacterial properties of tannins isolated from Dichrostachys cinerea

Abstract: Compounds of pharmacological interest (tannins) were isolated from Dichrostachys cinerea and assayed against Staphylococcus aureus, Shigella boydii, Shigella flexneri, Escherichia coli and Pseudomonas aeruginosa using the agar diffusion method. Tannins exhibited antibacterial activities against all the test microorganisms. Sh. flexneri was the most resistant to tannins isolated from the plant material followed by Sh. boydii, E. coli, Staph. aureus and P. aeruginosa respectively. Minimum inhibitory concentration of the tannins ranged between 4.0 and 5.5 mg/ml while the minimum bactericidal concentration ranged between 4.5 and 6.0 mg/ml.

Chemical composition and antimicrobial activity of the essential oil of Ocimum gratissimum L. growing in Eastern Kenya

Abstract: Hydro-distilled volatile oils from the leaves of Ocimum gratissimum L. (Lamiaceae) from Meru district in Eastern Kenya were analysed by gas chromatography-mass spectrometry (GC-MS) and also evaluated for antimicrobial activity. The oil was dominated by monoterpens which accounted for 92.48%. This monoterpene fraction was characterized by a high percentage of eugenol (68.8%). The other major monoterpenes were methyl eugenol (13.21%), cis-ocimene (7.47%), trans-ocimene (0.94%),
-pinene (1.10%) and camphor (0.95%). The sesquiterpenes present in fairly good amounts were germacrene D (4.25%) and trans-caryophyllene (1.69%). The minor sesquiterpenes were -farnesene (0.85%) and
- bisabolene (0.74%). The antimicrobial activities of the essential oils were evaluated against both Gram positive (Staphylococcus aureus, Bacillus spp.) and Gram negative (Escherichia coli, Pseudomonas aeruginosae, Salmonella typhi, Klebisiella pneumoniae, Proteus mirabilis) bacteria and a pathogenic fungus Candida albicans. The oil had pronounced antibacterial and antifungal activities on all the microbes.

Physiological response of common bean (Phaseolus vulgaris L.) seedlings to salinity stress

Abstract: The effect of salinity stress on five cultivars of common bean: Bassbeer, Beladi, Giza 3, HRS 516 and RO21 were evaluated on a sand/peat medium with different salinity levels (0, 50 and 100 mM NaCl) applied 3 weeks after germination for duration of 10 days. Salinity had adverse effects not only on the biomass yield and relative growth rate (RGRt), but also on other morphological parameters such as plant height, number of leaves, root length and shoot/root weight ratio. Photosynthesis, transpiration rate and stomatal conductance were adversely affected in all cultivars. Leaf osmotic potential and leaf turgor varied significantly among cultivars and salt levels. The interaction between cultivars and salt levels for photosynthesis, leaf osmotic potential and leaf turgor was highly significant at day 10 of salt treatment. The Na uptake among the cultivars varied in the order: HRS 516 highest survival rate and no symptoms of salt stress. RO21 was the most susceptible to salinity as it showed severe symptoms of salt stress and very low survival rate.

Assessing the nutritional status of beef cattle: current practices and future prospects

Abstract: Accurate determination of nutritional and health status of animals is invaluable in modern animal agriculture. Body weights and body condition scoring are the commonly used methods of assessing nutritional status of animals. This paper discusses drawbacks these methods have and highlights the benefits for using blood metabolites in assessing nutritional status of beef cattle. Blood metabolite levels indicate the extent of metabolism of energy, proteins and other nutrients in animals. Glucose, cholesterol, non-esterified fatty acids, protein, urea, creatinine, albumin, globulin, minerals, liver enzymes and haematology can be used objectively, reliably and routinely to assess the nutritional status of cattle. In Southern Africa, the use of these metabolites is rare due to lack of equipment for blood analysis and the high cost of analyzing the blood parameters. However, use of high value Nguni cattle in Southern Africa requires the use of blood parameters to accurately assess their nutritional status. Several factors, such as physiological status of an animal, breed, nutrition, season and age affect levels of blood metabolites. Combining body weights, body condition scores and blood metabolites increase accuracy of assessing the nutritional state and welfare of beef cattle. Key words: Body condition scoring, blood metabolites, nutritional status, cattle.

Comparative phytochemical evaluation, antimicrobial and antioxidant properties of Pleurotus ostreatus

Abstract: This study scientifically examined the phytochemistry, antioxidant and antimicrobial potencies of two organic extracts of Pleurotus ostreatus. Generally, both extracts were effective against 89.8% of the isolates tested with Bacillus subtilis (7.6 – 7.8 mm), Escherichia coli (7.6 – 8.2 mm) and Saccharomycee cerevisae (10.5 – 10.8 mm) exhibiting highest gram ±ve, gram –ve and fungal susceptibilities by agar well diffusion method, respectively. However, petroleum ether extract (PE) exhibited greater anti-gram negative bacterial activity than the acetone extract (AE) and further produced growth inhibition of these isolates in broth. Compared to PE, the acetone extract elicited higher total phenolic content and in vitro antioxidant capacity. Phytochemical analyses of the extracts revealed low to moderate levels of terpenoids, tannins, steroidal glycosides and carbohydrates, while flavonoids, alkaloids and cynogenic glycosides were not detected. The results indicate that P. ostreatus possesses antimicrobial and antioxidant potentials.

Larvicidal effect of Hemidesmus indicus , Gymnema sylvestre , and Eclipta prostrata,/i> against Culex qinquifaciatus mosquito larvae

Abstract: The larvicidal effect of aqueous extracts of Hemidesmus indicus roots, Gymnema sylvestre and Eclipta prostrata leaves were tested against Culex quinquefasciatus larvae at the concentrations of 1, 2, 3, 4 and 5% up to three days. All extracts showed larval mortality. Larval mortality was 100% with the use of 5% concentration of root extract of H. indicus, leaves extracts of G. sylvestre and E. prostrata after 2 days. Qualitative analysis of the phytochemicals of aqueous extracts revealed the presence of carbohydrates, saponins, phytosterols, phenols, flavonoids and tannins in all the plants. Quantitative analysis showed that the crude saponin was the major phytochemical constituent present in highest percentage followed by crude tannin in all three plants. It is suggested that all the three plants possess larvicidal properties that could be developed and used as natural insecticides for mosquito control.

Protocol for isolation of genomic DNA from dry and fresh roots of medicinal plants suitable for RAPD and restriction digestion

Abstract: A simple and efficient protocol for isolating genomic DNA from fresh and dry roots of medicinal plants was developed. It involves a modified CTAB procedure using 3%CTAB, 4% b-mercaptoethanol, 2 M NaCl and 5% PVP. The extraction was carried out at 70°C. A slight increase in the concentrations of these chemical components and temperature helped in the removal of secondary metabolites and polysaccharides from the DNA preparation. The quantity and purity of isolated DNA was higher when compared with DNA extracted by the methods of Dellaporta et al. (1983) and Doyle and Doyle (1990). The DNA yield ranged from 33 to 68 µg per g of root samples and it was 1.47 times greater in dried than fresh samples. The DNA samples were found suitable for analysis with restriction enzyme digestion and random amplification of polymorphic DNA (RAPD). The total duration for DNA extraction from roots of medicinal plants using this protocol was 135 min as compared to 225 min with existing protocols. Key words: DNA isolation, roots, medicinal plants, secondary metabolite, PCR amplification, restriction digestion.

In vitro antimicrobial activity of Trapa natans L. fruit rind extracted in different solvents

Abstract: Trapa natans L. fruit rind was extracted in different solvents with increasing polarity; 1,4-dioxan, chloroform, acetone, imethylformamide, ethanol and water. The extractive yield ranged from 0.62 –12.62%. The antibacterial activity of all the extracts was determined by agar disc diffusion method. Maximum antibacterial activity was observed against Gram negative bacteria. The resistant Gram negative strains were C. fruendii, E. aerogenes, E. coli, P. vulgaris, P. aeruginosa and S. typhimurium. Amongst Gram positive bacteria, M. flavus was the most susceptible bacteria and B. subtilis was most resistant. The moulds showed better antifungal activity than yeast. A. niger was the most resistant fungal strain. The best antimicrobial activity was with 1,4-dioxan extract and the least activity was with petroleum ether extract. The inhibitory effects of the extracts were comparable with the standard antimicrobics used. This work has highlighted the antimicrobial effects of fruit rind of Trapa natans L. on some of the medically important pathogens.

Fungi and some mycotoxins contaminating rice (Oryza Sativa) in Niger State, Nigeria

Abstract: Study on the fungi and some mycotoxins (Aflatoxin B1 - AFB1, ochratoxin A - OTA and zearalenone -ZEN) contaminating rice (Oryza sativa) in Niger State of Nigeria was carried out. One thousand and sixty two fungi were isolated and identified from one hundred and ninety six mouldy rice samples collected from the state. The major fungal genera contaminating rice were Aspergillus, Penicillium, Fusarium, Alternaria, Mucor, Rhizopus, Trichoderma, Curvularia, elminthosporium and Cladosporium. The most prevalent fungal species on rice were .Penicillium spp., A. flavus, A. parasiticus, A. niger, Mucor spp., Rhizopus spp. and Alternaria spp. The commonest fungal contaminants of the dry, harmattan; dry-hot and rainy seasons were A. niger, Penicillium spp. and A. flavus respectively. AFB1 was detected in 97 of the samples analyzed at concentrations between 20-1642 ug/kg. Fifty six of the one hundred and forty samples analyzed for OTA contained the toxin (24 – 1164 ug/kg). Zearalenone was found in ninety three of the one hundred and ninety six mouldy rice samples analyzed at concentrations of between 24 and 1169 ug/kg. Twenty two samples were concurrently contaminated with the three toxins while seven others were found to contain both AFB1 and OTA. AFB1 and ZEN occurred together in twelve samples, and eight samples contained both OTA and ZEN.

Biological, ecological and agronomic significance of plant phenolic compounds in rhizosphere of the symbiotic legumes

Abstract: Phenolics are low molecular compounds ubiquitous in all tissues of higher plants with great significance in plant development. Our understanding of some phenolic compounds in the last few decades has greatly improved. However, their biological, ecological and agronomical significance in the rhizosphere of most symbiotic legumes is much less clear. Further understanding of these biomolecules will increase our knowledge of their contribution in soil and water conservation, weed management, mineral element nutrition, their impact as signal molecule in certain symbiotic relationships, and their role as defence molecules against soil pests and pathogens. This article reviews the bioecological and agronomical significance of phenolic compounds in the rhizosphere of a few studied symbiotic legumes and other plants.

Decolorization of textile dyes and their effluents using white rot fungi

Abstract: Reactive dyes are important chemical pollutants from textile industries .The two species of white rot fungi were evaluated for their ability to decolorize Blue CA, Black B133, Corazol Violet SR. Trametes hirsuta and Pleurotus florida displayed the greatest extent of decolorization. Laccase is the ligneolytic enzyme from these fungi. The laccase activity was measured using both solid and aqueous state assays. The dye absorption ability of the mycelium was studied using appropriate medium containing dyes at the concentration of 75 mg/l. The effective decolorization of Blue CA and Corazol Violet SR dyes by both microorganisms were observed in the fifth day of incubation. Further decolorization activity was verified using various concentrations of dyes such as 25, 50 and 75 mg/l. Maximum decolorization was observed in Blue CA and Corazol Violet SR dyes. The effluent from the dye house was treated using both organisms with different concentration of glucose (1 and 2%). Effective decolourization was found to be more by the Pleurotus florida in 2% glucose.

In Vitro screening of tomato genotypes for drought resistance using polyethylene glycol

Abstract: Drought is a major abiotic factor that limits plant growth and productivity. Tomato is an important vegetable crop and area under production is limited by irrigation water scarcity. Effort was made to screen tomato germplasm under in vitro condition using polyethylene glycol (PEG) at four concentrations (0, 20, 40 and 60 g/l) with two replications in factorial CRD. Important seedling characters like root length and weight; shoot length and weight were recorded. Drought resistant mutant derivatives and hybrid produced using mutant derivative as female parent performed significantly superior for root characters. Decrease in seedling growth was worth notice with increasing concentration of PEG indicating precise nature of the in vitro screening. Mutant hybrid and its derivatives were observed with outstanding ability to continue root growth under in vitro stress conditions indicating there ability to fight with sever water stress situation. These results were further confirmed for early indication traits in raised bed seedlings and fully-grown mature plants under field conditions. At all three experimental conditions, mutant derivatives and hybrids performed better than cultivated genotypes under all levels of water stress. Based on results, Hy-3 and MTG 1-4 were found to be drought resistant due to there remarkable performance at all levels of water stress. This in vitro screening method is potential and cost effective method to screen large set of germplasm within very less time period and accurately.

Impact of effluent from Bodija abattoir on the physicochemical parameters of Oshunkaye stream in Ibadan City, Nigeria

Abstract: The problem of getting quality drinking water is increasing as untreated effluents are discharged into surface water bodies. The impact of effluent from Bodija abattoir, the biggest abattoir in Ibadan, western Nigeria on the physico-chemical parameters of Oshunkaye stream was investigated. The qualities of effluent and stream water (before and after mixing with effluent) were studied using the basic water quality parameters. The ranges of the physico-chemical parameters studied were as follows: pH 6.92 –8.18, temperature 31 – 34oC, total solids 7726 – 47 630 mg/l, total suspended solids 1498 – 6803 mg/l, chemical oxygen demand 947 - 2566 mg/l, oil and grease 2500 –12590 mg/l, nitrate 62 – 159 mg/l, phosphate 142 - 180 mg/l, chloride 1052 – 1727 mg/l, lead 0.08 – 0.2 mg/l, nickel 0.18 – 0.49 mg/l, copper not detected – 0.14 mg/l, zinc 0.67 – 6.08 mg/l and cadmium (not detected). Using Prati’s et al classification of surface water quality, Oshunkaye stream fell in the class of grossly polluted water after mixing with effluent from the abattoir. While before mixing, it fell in class of slightly polluted. Hence the abattoir effluent needs to be treated before discharge into the receiving stream to reduce health hazard.