A comparative study of the wild and mutated heavy metal resistant Klebsiella variicola generated for cadmium bioremediation

Ten indigenous heavy metals resistant bacteria were isolated from the discharged effluent of Biological Sciences building at Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria. The bacterial strains were isolated using enrichment method in tryptone soya agar (TSA) supplemented with 100 mg/L of Pb, Cd, As, and Ni. All the isolated bacteria showed multiple tolerances to the heavy metals; however, strain GBB 220, which showed a maximum tolerable concentrations (MTCs) of 2000, 1200, 4700, and 1000 mg/L for Pb, Cd, As, and Ni, respectively, was selected for further studies. The bacterium was identified by 16S rRNA sequences as Klebsiella variicola and was subjected to mutational enhancement by acridine orange and ethidium bromide. Eight mutants were recovered, strains K. variicola MutAa–Ad showed improvement in their MTCs of 2500, 2200, and 5000 mg/L for Pb, Cd, and As whereas K. variicola MutEa–Ed had same MTCs as the wild type except for cadmium which increased from 1200 to 1500 mg/L. The antibiotic susceptibility patterns showed that all the strains of K. variicola had multiple resistances to some of the antibiotics. The K. variicola mutants had their optimum pH at 5 and 8 while the wild type had optimum pH at 7 and 8. The cadmium removal efficiency of 97.9% at pH 7, 97.7% at pH 8, and 99.4% at pH 7 was observed for K. variicola Wt, K. variicola Mut Eb, and K. variicola Mut Ac, respectively. These findings suggested that the artificially mutated strains of K. variicola may be applied to remove cadmium from polluted environment.     

Assessment of extracts from some tropical plants in the management of termite (Termitidae: Isoptera) in Ogun State,Nigeria

This study investigated the efficacy of extracts from four plants, namely: Azadirachta indica, Ocimum gratissimum, Vernonia amygdalina and Nicotiana tabaccum at managing the population of termites in the laboratory and in the field. The synthetic insecticide (Chlorpyrifos 0.1%) and water were included in the study as controls. In the laboratory, contact toxicity was conducted by topical application of the treatments to the thorax of soldier termite Macrotermes bellicossus and mortality noted. The repellent action of the treatments was tested by releasing 10 of the termites into the center of Petri dishes lined with treated filter paper. The number of insects present on the control and treatment halves was recorded and the percentage repellence values were computed. The residual effects of the treatments was studied by placing five termites in Petri dishes lined with filter paper that have been treated with the treatments 24 hours prior to its placement and insect mortality was noted. The studies were conducted using complete randomised design with four replicates. Field trial of the treatments was conducted on termitaria that were demolished and disinfested with five liters of the treatments. The results showed that all the treatments caused 95–100% mean insect mortality 10 hours after insect exposure and have repellence values of between 40 and 65%. The residual effects of the treatments caused termite mean mortality of 100% in Chlorpyrifos and N. tabacum-treated surfaces and between 50 and 65% in others. In the field, only A. indica and Chlopyrifos were effective at curtailing termite upsurge and rebuild of termitaria.     

Assessment of AM biotechnology in improving agricultural productivity of nutrient-deficient soil in the tropics

Abstract

Growth, nutrient content and nodulation response of cowpea plants (Vigna unguiculata L. Walp) inoculated with a Arbuscular Mycorrhiza (AM) fungus (Glomus etunicatum) and Bradyrhizobium (BR) strain IRC 25B peat-based were assessed on an alfisol in a two-cropping cycle experiment conducted in the greenhouse. A total of 5 kg sieved unsterilized topsoil plastic pots was amended with compost consisting of 2.4% N, 1.7% P, 2.7% Ca, 0.4% Mg and 0.7% Fe. Analysis from this first cropping cycle showed that all cowpea plants were infected with mycorrhiza in both AM inoculated and uninoculated treatments. However, all the AM inoculated plants had higher infections than the uninoculated cowpea plants. Nevertheless, nodule number and nodule weight of cowpea plants generally increased in response to compost application when used alone, or when combined with BR or AM; except for nodule weight of BR + Compost treatment. At 13 weeks after planting, the plants were harvested for a second cropping cycle experimental analysis. Results showed higher mycorrhizal infections in all the treatments inoculated with AM. However, infection was highest in cowpea plants treated with AM + BR + Compost, followed by those treated with AM + BR. This shows an increase in the number of AM propagules during the period of cropping. All other parameters measured were found generally lower in their mean values compared to the first cropping cycle. It was observed in this study that compost applications with AM inoculation could substitute for inorganic fertilizer. Thus, tropical countries should direct their efforts towards making the best use of AM to improve conditions for the peasant farmers that account for over 70% agricultural productivity in the region.     

Aframomum melegueta: a potential botanical pesticide against Sitotroga cerealella infestation on two paddy varieties

This study was conducted to investigate the potential of Aframomum melegueta leaf and seed as biopesticide against Sitotroga cerealella infestation on two paddy varieties at ambient temperature of 28 °C ± 2 °C and relative humidity of 75?±?5%. The two paddy varieties used were FARO 44 and FARO 52. Leaf and seed powders of A. melegueta were made at 0.1, 0.2, 0.4, 0.6 and 0.8 g while the extracts were made at 1, 2, 3, 4 and 5%. Mortality of the insect on the two paddy varieties was record after 24, 48 and 72?h of application of the powders and extracts of this plant. The highest number of the insect was observed on FARO 52 treated with seed powders and extracts of A. melegueta. Only the seed extracts were able to achieve 100% moth mortality within 72 h of application at 4% concentration and were significantly (p?<?0.05) different from others. The powders and extracts of the plant significantly reduced or prevented the adult emergence of the insect and increased their developmental period as well reduced or prevented seed weight loss with seed powders and extracts having the greatest effect on the paddy variety FARO 44. The antinutritional components present in the two paddy varieties include phytate, oxalate, total phenol and tannin cyanide, and the amylase content was also determined, with FARO 44 having the highest value of 17.31, 0.18, 0.43, 10.46 and 5.49 for phytate, oxalate, tannin, cyanide and amylase content, respectively. Powders and extracts of A. melegueta could be introduced into pest management techniques since they are effective against S. cerealella.     

Multimodal Brain Connectivity Analysis in Unmedicated Late-Life Depression

Late-life depression (LLD) is a common disorder associated with emotional distress, cognitive impairment and somatic complains. Structural abnormalities have been suggested as one of the main neurobiological correlates in LLD. However the relationship between these structural abnormalities and altered functional brain networks in LLD remains poorly understood. 15 healthy elderly comparison subjects from the community and 10 unmedicated and symptomatic subjects with geriatric depression were selected for this study. For each subject, 87 regions of interest (ROI) were generated from whole brain anatomical parcellation of resting state fMRI data. Whole-brain ROI-wise correlations were calculated and compared between groups. Group differences were assessed using an analysis of covariance after controlling for age, sex and education with multiple comparison correction using the false discovery rate. Structural connectivity was assessed by tract-based spatial statistics (TBSS). LLD subjects had significantly decreased connectivity between the right accumbens area (rA) and the right medial orbitofrontal cortex (rmOFC) as well as between the right rostral anterior cingulate cortex (rrACC) and bilateral superior frontal gyrus (bsSFG). Altered connectivity of rrACC with the bsSFG was significantly correlated with depression severity in depressed subjects. TBSS analysis showed a 20% reduction in fractional anisotropy (FA) in the right Forceps Minor (rFM) in depressed subjects. rFM FA values were positively correlated with rA-rmOFC and rrACC-bsFG functional connectivity values in our total study sample. Coordinated structural and functional impairment in circuits involved in emotion regulation and reward pathways play an important role in the pathophysiology of LLD.     

Co-endemicity of Loiasis and Onchocerciasis in Rain Forest Communities in Southwestern Nigeria

BackgroundLoiasis is currently receiving attention as a disease of public health importance because of the possibility of increased risk of developing neurologic serious adverse event following mass ivermectin treatment against onchocerciasis in individual co-infected with Onchocerca volvulus and Loa loa.Conclusions/SignificanceLow prevalence of onchocerciasis and loiasis co-infection in this study suggests that loiasis may not pose a serious epidemiological threat to the continuous distribution and sustainability of ivermectin for the treatment of onchocerciasis. Evaluation of the interruption of onchocerciasis transmissions in this region using all the indicators set forth by WHO is therefore suggested.     

Evaluation of bioactive flavonols and ent-kaurenes in the 2,4-dichlorophenoxyacetic acid-induced calli of Senegalia nigrescens using FTIR and GC–MS

Journal of Plant Biochemistry and Biotechnology - The increasing demand for plant-derived pharmacologically active compounds calls for sustainable alternative sources and conservation of medicinal...     

Proline and valine transport in Agrobacterium tumefaciens C-58

Abstract The transport of proline and valine by Agrobacterium tumefaciens was investigated. Proline uptake by starved cells was found to be higher in the presence of glucose than in its absence. Valine uptake, on the other hand, was lowered in the presence of glucose. Proline uptake was found to be insensitive to the action of dicyclohexyl carbodiimide (DCCD), a membrane ATPase inhibitor, whereas valine uptake appeared to show some sensitivity to this agent. The results obtained seem to suggest that the two transport systems make use of different energy stores.     

Floral composition and diversity of the lagos coastal environment,South-Western,Nigeria

The present study investigates the floral diversity of the Lagos coastal environments by sampling 21 points using the quadrat method. The study revealed two major aquatic ecosystem types (mangrove and freshwater swamp) and recorded 125 species belonging to 108 genera and 49 families. While Alchornea cordifolia and Raphia hookeri were found as the most frequent, Acalypha crenata and Acrostichum aureum were the least abundant species. The highest and lowest species-rich locations were Unilag (n = 125 species) and Abule Osun (n = 2 species), respectively. The vegetation structure of the LCE is dominated by herbaceous species. Our findings provide insights on the flora diversity of the LCE, and a guideline for the effective conservation of near-threatened species such as Nauclea diderrichii and Mitragyna stipulosa in this coastal ecosystem is presented.