Biocompatibility and ecotoxicity concerns associated with chemically produced metallic nanoparticles have led to an increasing interest in the development of environmentally benign alternatives for nanoparticle synthesis using biological platforms. Herein, we report the utilization of an extract of seed-derived callus of Catharanthus roseus for the production of stable silver nanoparticles (Ag NPs). The bioreduction of silver ions was evident from UV-Vis spectroscopy results: the absorption maxima were observed at 425 nm, indicative of elemental silver. Transmission electron micrographs revealed that the Ag NPs were well-dispersed and predominantly spherical with particle sizes in the range of 2-15 nm. The synthesized Ag NPs exhibited colloidal stability in an aqueous dispersion for a period of 120 days, as indicated by UV-Vis absorbance spectra and zeta potential measurements. Fourier transform infrared spectroscopy revealed the possible utilization of hydroxyl groups and amides in the reduction of silver ions and surface stabilization of the Ag NPs, respectively. Notably, the synthesized Ag NPs showed considerable antibacterial action against Escherichia coli even after 8 weeks of storage under ambient conditions. Thus, cell extracts of cultured callus of Catharanthus roseus could be explored as an ecofriendly platform for the synthesis of stable and functional nanoparticles.
Fungi associated with three cultivars of melon seeds were investigated. The mycoflora were found to be more on the unshelled than on the shelled seeds of all the three cultirars tested. A total of nine fungal genera were isolated and identified while two were unidentified. C. vulgaris was infected with all the nine genera including the two unidentified genera. Percentage incidence of infection was observed to be higher for the unshelled than with the shelled seeds for all the cultivars. The genus, Aspergillus was the most predominant, with A. niger topping the list followed by R. stolonifer and the least was A. flavus. In view of the harmful effects of aflatoxin production by Aspergillus spp caution must be exercised in the consumption of stored 'egusi' until an adequate control measure is in place.
The effects of some phytohormones [indole acetic acid (IAA), indole butyric acid (IBA), gibelleric acid (GA 3), and kinetin] on cell dry weight, cell number, cell size, protein and chlorophyll contents of Chlorella sorokiniana IAM-C212 were investigated under photoautotrophic conditions. Treatment with IAA (15 mg/l) and IBA (15 mg/l) resulted in significantly higher dry cell weight and cell number than the control (P < 0.05) but there were no significant effects of GA 3 and kinetin on cell growth as expressed by dry cell concentration (g/l) and cell population (cells/ml). Treatment with IAA at a concentration of 10 or 15 mg/l gave the highest cell dry concentration of 4.68 g/l after eight days of cultivation, which is more than 9 times higher than the value obtained in the control culture (without phytohormone). The optimum concentration of each of the phytohormones for C. sorokiniana cell enlargement was 20 mg/l. At this concentration, the average cell sizes were 81.07, 78.67, 78.07, 66.90 and 68.1 µm for GA 3 , kinetin, IAA, IBA and control, respectively. Addition of 15 mg/l of IAA or GA 3 to the culture resulted in significantly higher extractable chlorophyll contents than the control (P < 0.05) but the effects of IBA and kinetin were not significant (P > 0.05). The protein contents of the cells cultivated with 20 or 10 mg/l of GA 3 , 15 mg/l of kinetin, and 15 mg/l of IBA or IAA were 46.64, 45.83 and 45.81%, respectively. In the control experiment, the protein content was 43.38% after eight days of cultivation, showing that treatment with these phytohormones had no significant effect on the protein contents of the cells (P > 0.05). Combination of IBA and GA 3 exhibited synergistic effect on growth and productivity of C. sorokiniana but there was no synergistic effect when IAA was combined with either GA 3 or kinetin.
Leaf blight and corm rot of taro (Colocasia esculenta (L.) Schott) caused by Phytophthora colocasiae Raciborski is the most disparaging disease of taro inducing severe losses in yield and quality of taro corms. Investigations were carried out in Umudike in 2016 and 2017 to determine the pathotypes present in that locality with a view to screening them on available taro genotypes for resistant cultivars. Symptomatic taro plant samples were collected from Taro Project Farm of the National Root Crops Research Institute, Umudike. Leaf tissue sections were excised from the periphery of lesions on symptomatic leaf, surface sterilized in 10% Sodium Hypochlorite solution for 2 minutes, rinsed in three changes of sterile distilled water and plated on Water Agar (WA). Mycelia emerging from diseased tissues after incubation were aseptically transferred to Corn Meal Agar (CMA). A total of 15 fungal isolates under 6 groups of species were obtained and these isolates were transferred to Carrot Agar (CA) from time to time until pure cultures were obtained. Based on varied cultural patterns, morphological characteristics and microscopic examination, the isolates were identified as Phytophthora sp, Fusarium sp FSSC, Fusarium solani, F. oxysporum and F. equiseti. Pathogenicity test confirmed that only Phytophthora sp induced leaf blight on detached leaf of taro plant. Molecular characterization of the isolates via Internal Transcribed Spacer (ITS) sequence analyses confirmed that the already implicated Phytophthora species was Phytophthora sansomeana. This is apparently the first report of P. sansomeana as a taro leaf blight pathogen in addition to the already known P. colocasisae.
Agricultural production and the agro-food industry furnish large volumes of solid wastes, which when unutilized could lead to environmental pollution. An attempt was made to utilize wastes from the oil palm and timber industries for the cultivation of Lentinus squarrosulus, a Nigerian edible mushroom. Mahogany sawdust (MSD), Gmelina sawdust (GSD), oil palm fruit fibre (OPFF) and oil palm empty fruit bunch (OPEFB) significantly influenced crop cycle time, yield, nutritional properties and market quality of the mushroom. The shortest crop cycle time achieved (47 days) was with Gmelina sawdust. Oil palm fruit fibre proved a better substrate for the production of mushrooms with higher yields and protein content (30.10 g/kg substrate and 27.42%). Yield and protein content of harvested mushrooms were strongly correlated with the nitrogen content of the substrates. Fruit bodies with the lowest fat content were harvested from Gmelina sawdust. Fat contents of the mushrooms showed a positive and significant correlation with the cellulose content of the waste. Oil palm fruit fibre yielded the highest quality mushrooms, with 26% in the >7 cm group while GSD and OPEFB had 0% in the same quality group. Considering the desirable characteristics of yield, protein content and market quality, OPFF proved to be a good substrate which could be exploited for large scale production of L. squarrosulus.
Development of efficient substrate formulas to improve yield and shorten production time is one of the prerequisites for commercial cultivation of edible mushrooms. In this study, fifteen substrate formulas consisting of varying ratios of palm press fibre (PPF), mahogany sawdust (MS), Gmelina sawdust, wheat bran (WB), and fixed proportions of 1% calcium carbonate (CaCO3) and 1% sucrose were assessed for efficient Lentinus squarrosulus production. Proximate compositions of mushrooms produced on the different substrate formulas were also analysed and compared. Substrate formulations containing 85% PPF, 13% WB, 1% CaCO3, and 1% sucrose were found to produce the highest carpophore yield, biological efficiency and size (206.5 g/kg, 61.96%, and 7.26 g, respectively). Days to production (first harvest) tended to increase with an increase in the amount of WB in the substrate formulas, except for PPF based formulas. The addition of WB in amounts equivalent to 8~18% in substrate formulas containing 80~90% PPF resulted in a decrease in the time to first harvest by an average of 17.7 days compared to 80~90% MS with similar treatment. Nutritional content of mushrooms was affected by the different substrate formulas. Protein content was high for mushrooms produced on formulas containing PPF as the basal substrate. Thus, formulas comprising PPF, WB, CaCO3, and sucrose at 85% : 13% : 1% : 1%) respectively could be explored as starter basal ingredients for efficient large scale production of L. squarrosulus.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.