Incidence of aflatoxins, fumonisins, trichothecenes and ochratoxins in Nigerian foods and possible intervention strategies

Mycotoxins are toxic secondary metabolites produced by some species of fungi. Aflatoxins, fumonisins, trichothecenes and ochratoxins are the common mycotoxins in Nigeria. Aflatoxin is the most frequently reported in literatures, with trichothecenes being the least, they cause yield loss to farmers as well as constituting major health risk to humans. The occurrence of mycotoxins in food is a serious problem that Nigeria is facing presently, as it continues to pose threat to feed and food safety of animals and humans. There is the need to seek for approaches that would lead to reduction in their toxicity. The practice of good sanitary measures right from the farm to storage, creation of awareness campaign to indicate the toxic effects associated with mycotoxin poisonings in humans and livestock, and proper evaluation of food crops for its presence can go a long way in achieving the target reduction in incidence of mycotoxins in Nigeria

Comparative biochemical and molecular evaluation of swarming of Proteus and effects of anti-swarm agents

In addition to inadequate understanding of swarming motility and virulence of Proteus, there is paucity of information on the relative effectiveness of the various anti-swarm agents. The anti-swarming effects of urea, sodium dodecylsulphate (SDS) and trihydroxymethylglycine (Tris) on 40 clinical isolates of Proteus Spp. were comparatively investigated and plasmids associated with swarming were characterized. The three substances elicited a comparable concentration-dependent anti-swarming property at 0.25 – 1.25% on nutrient agar. Anti-swarm agents displayed heterogeneity in their ability to cause significant decreases in the expression of virulence factors. Swarm motility was further found to be strongly associated with the expression of virulence factors in these strains. Of the Proteus strains tested, 32 were found to harbour 1 – 4 plasmids of size ranging from 6.0 – 33.5 kb. Plasmid curing resulted in loss of swarming in 65.6% of these strains. In order to reduce the risk of infection with virulent Proteus strains, the laboratory use of urea and SDS is suggested. Key Words: Proteus, swarming, urea, SDS, Tris. African Journal of Biotechnology Vol.3(1) 2004: 99-10

Grapevines escaping trunk diseases in New Zealand vineyards have a distinct microbiome structure

Grapevine trunk diseases (GTDs) are a substantial challenge to viticulture, especially with a lack of available control measures. The lack of approved fungicides necessitates the exploration of alternative controls. One promising approach is the investigation of disease escape plants, which remain healthy under high disease pressure, likely due to their microbiome function. This study explored the microbiome of grapevines with the disease escape phenotype. DNA metabarcoding of the ribosomal internal transcribed spacer 1 (ITS1) and 16S ribosomal RNA gene was applied to trunk tissues of GTD escape and adjacent diseased vines. Our findings showed that the GTD escape vines had a significantly different microbiome compared with diseased vines. The GTD escape vines consistently harbored a higher relative abundance of the bacterial taxa Pseudomonas and Hymenobacter. Among fungi, Aureobasidium and Rhodotorula were differentially associated with GTD escape vines, while the GTD pathogen, Eutypa, was associated with the diseased vines. This is the first report of the link between the GTD escape phenotype and the grapevine microbiome

African Journal of Pure and Applied Chemistry Ab-initio and DFT studies of the kinetics, mechanisms and thermodynamics of the gas-phase pyrolysis of ethyl bromide

The kinetics, mechanisms, thermodynamics and vibrational studies of the pyrolysis of ethyl bromide in the gas -phase at 623 K was studied using HF at 3-21G, 6-31G* and DFT with B3LYP/6 31G*, 6-311++G (2df, 2p) basis sets. The reaction proved to be a unimolecular reaction and followed a first order rate equatio

Gibberellic Acid Production by Fusarium moniliforme and Aspergillus niger Using Submerged Fermentation of Banana Peel

The present study aimed to produce gibberellic acid through fermentation using banana (Musa sapientum) peel waste as substrate. Banana peel, a domestic and industrial waste, constitutes a potential source of cheap fermentable substrate for the production of other value-added products. Fusarium moniliforme ATCC 10052 and Aspergillus niger CBS 513.88 were used as fermenting organisms. The substrate was dried, ground and its proximate composition determined. The powdered substrate was added to a modified CzapekDox broth (a semisynthetic medium), with Carboxyl methylcellulose (CMC) as control. The fermentation conditions were: pH 5.5; inoculum size 1% (5 × 105 spores/mL F. moniliforme) (2 × 106 spores/mL A. niger); substrate concentration 2 g; temperature 25 ± 2 oC; fermentation time 7 days. The fermentation was optimized by varying pH, inoculum size, substrate concentration and fermentation time. The extracted GA was subjected to infra-red spectroscopy using FT-IR. The parameters which gave the highest GA yields were thereafter combined in a single fermentation. The results of proximate analysis of banana peel substrate revealed 8.65% moisture, 9.54% protein, 5.40% lipids, 11.45% ash, 22.34% crude fibre, and 42.62% carbohydrate. The GA yields of 13.55 g/L and 12.44 g/L were produced from the banana peel substrate and 3.62 and 2.61 g/L from the CMC control by F. moniliforme and A. niger respectively. Under optimized conditions, F. moniliforme produced 17.48 g/L GA, while A. niger produced 13.50 g/L. Extracted GA was similar to standard GA sample and the present results support the potential use of banana peel for fermentative GA production

Theoretical Studies of the Effects of alpha -methylation and beta- methylation on the Gas - Phase Kinetics of Thermal Decomposition of Allyl formates

The gas phase pyrolytic reaction of allyl formate (I), its α-methylated compound (II) and β- methylated compound (III) were studied theoretically with semi-empirical PM3, hatree-fock HF/3-21G and density functional theory, DFT (B3LYP/6-31G*) methods. The decomposition of these compounds proceeds by a concerted [1, 5] hydrogen shift through a six-centered transition state (TS) geometry. The overall result of calculations shows that the reactivity of the thermal decomposition increases consequent to steric releasing effect in the transition state by the methyl group at the α-position, hence it is rate enhancing while reactivity decreases upon β-methylation, decreasing the rate of reaction. Also, it is found that rate enhancement due to C-O bond stretching in the formation of TS is more significant as a rate determinant than the acidic nature of the eliminated formyl hydrogen. Keywords: Kinetics, hydrogen shift, allyl formate, mechanism, α-,β-methylatio

Drought Stress Modulation by Biochar and Effects on Soil and Performance of Seedlings of Urban Forest Tree Species

Aims: This study was designed to examine the effects of watering regime and biochar on soil properties and performance of seedlings of urban forest tree species (UFTS) in the nursery. Study Design: The experiment was a 5 by 3 by 2 factorial scheme involving urban forest tree species, watering regimes and biochar amendment or not. Place and Duration of Study: seedlings of five UFTS were raised in the Nursery and Screenhouse of Wesley University, Ondo, a rainforest zone of Nigeria. Methodology: Seedlings of five Urban Forest Tree Species (UFTS) were subjected to watering at 80, 60 and 35% field capacity (FC) with or without biochar amendment. UFTS evaluated are: Bauhinia monandra, Delonix regia, Terminalia catappa, Dypsis lutescens and Veitchia merrillii. Results: Watering regime and biochar amendment exerted significant effects on soil physical and chemical properties, physiological attributes and biochemical constituents and performance o the UFTS evaluated. Watering at 60 and 35% FC increased bulk and particle densities but reduced significantly (P<.05) soil moisture content at field capacity compare with watering at 80% FC. Further, the 60 and 35% FC watering exhibited low N, available K+, Ca2+ and Mg2+. Addition of biochar to the variously watered soil considerably reduced bulk density but remarkably increased porosity, field capacity moisture and plant available moisture. Biochar amendment increased soil pH, total and volatile organic matter contents, available K+ and Ca2+, extractable Mg2+ and dissolved phosphate (PO43+). The responses of growth traits and biochemical constituents of UFTS to watering regimes was species specific. Relative to 80 % FC watering, seedling growth attributes reduced significantly under deficit water application (60 and 35% FC) in addition to remarkable accumulation of osmolytes (osmoprotectants) and enzymatic activities. Biochar amendment enhanced accumulation of osmolytes and activities of superoxide dismutase, guaiacol peroxidase and catalase enzymes of UFTS seedlings. Conclusion: Differential watering and biochar amendment affected soil physical and chemical properties and growth of UFTS seedlings evaluated. Biochar amendment of the variously watered soil enhanced seedling growth, and appear as effective strategy for improving soil properties and UFTS performance, and for mitigation of adverse effects of suboptimal watering

PM3 Semi Empirical Quantum Mechanical Calculations on a Novel Dichlorobis (N-{4-[(2-pyrimidinyl-kN-amino)sulfonyl}acetamide]copper(II), Containing a Metabolite N-acetylsulfadiazine

ABSTRACT A novel Dichlorobi

CHARACTERIZATION AND COMPARATIVE RESPONSE OF RHIZOBIA ISOLATES FROM ROOT NOODLES OF SELECTED WEED SPECIES AND SOYBEAN (Glycine max) TO ENVIRONMENTAL FACTORS

Screening and selecting the most effective strains of rhizobium is important for biological nitrogen fixation. To determine the effects of environmental factors on rhizobia strains associated with some selected leguminous weed species, rhizobia strains isolated from root nodules of five weed species (Mimosa pudica, Crotolaria retusa, Desmodium triflorum, Canavalina ensiformis, Stylosanthes spp.) were subjected to varying temperature, salinity, and pH in the laboratory. Results indicated better growths at temperatures of 30 and 370C compared to the temperature of 250C.  Results further showed that microbial growth was optimal at 1.5% salt concentration. Optimum growth was also obtained at the pH range of 5 and 8. The study further revealed by a series of morphological and biochemical tests that all the strains were gram-negative, rod-shaped, and mucous producing. Rhizobia strains from leguminous weeds were found to exhibit faster growth than the strain nodulating soybean in all the conditions to which they were subjected. A cross inoculation study was therefore recommended to access the compatibility of these rhizobial strains from the wild with cultivated leguminous plant species