Annual Research & Review in Biology

Aims: The primary aim of this work was to investigate the impact of foliar application of SA on the leaf gas exchange, the accumulation of secondary metabolites and Lipoxygenase Inhibitory activity (LOX) in medicinal plant C. asiatica.

Study Design: The study used randomized complete block design (RCBD) replicated three rwith three replications

Place and Duration of Study: Department of Biology, Universiti Putra Malaysia between January 2014 and March 2014.

Methodology: Cantella asiatica was propagated in individual poly bags filled with sand, coco dust and compost in the ratio of 1:1:1 and chicken dung (50 g) per poly bag. The plant was left for a month in a nursery to be acclimatized until they were ready for SA treatment. After a month, the plants were sprayed with two concentrations (1 µM and 10 µM) of salicylic acid solution (SA). Control plants (0 µM) were sprayed with same solution but without SA. The leaf gas exchange, total flavonoid, saponin, Glutathione (GSH), Oxidized Glutathione (GSSG), Phenyll alanine lyase (PAL), Chalcone synthase activity (CHS) and Lipoxygenase inhibitory activity (LOX) was measured.  

Results: It was found that production of secondary metabolites (total flavonoids and saponin), GSH, GSSG, PAL, CHS and LOX were solely contributed by interaction of SA levels and plant parts in the descending manner came in leaf treated with 10 µM SA> leaf-1 µM SA>leaf 0 µM SA> stem 10 µM SA> stem 1 µM SA> stem -0 µM SA> root 10 µM SA> root-1 µM SA > root 0 µM SA. High concentration of salicylic acid application (10 µM) was found to be more effective in enhancing the leaf gas exchange traits compared to low concentration (1 µM). Interestingly, it was found that increase in net photosynthesis have a high significant correlation with total flavonoid, total saponin, GSH, GSSG and LOX, indicating that up-regulation of photosynthetic capacity of C. asiatica treated with SA, enhanced the production of secondary metabolites, antioxidant and Lipoxygenase inhibitory activity (LOX). This study also showed that there was involvement of CHS and PAL activity in an increase in the production of secondary metabolites and antioxidant activities under SA application.

Conclusion: It was found that SA enhances photosynthetic capacity of C. asiatica. This might be due to increase in PAL and CHS activity that was observed during the study. Furthermore, the production of secondary metabolites, antioxidant enzyme and Lipoxygenase inhibitory activity was elevated during the foliar SA application.

Aim: To evaluate antibacterial effect of haemolymph in edible snail against multi-drug resistant bacterial isolates.

Study Design: This was an experimental study involving susceptibility testing of bacterial isolates to haemolymph extracts of edible snail.

Place and Duration of Study: The experiments were carried out at the School of Biomedical and Allied Health Sciences of the University of Ghana from February to June, 2014.

Methods: Haemolymph was extracted from two Achatina achatina snails (haemolymph extract from one of the snails was labelled “Haemolymph A” and the other “Haemolymph B”). Both haemolymph extracts were tested against 15 multi-drug resistant isolates each of Staphlyococcus aureus, Pseudomonas aeruginosa and Escherichia coli by the agar well diffusion method.

Results: Overall, the proportion of isolates inhibited by Haemolymph A were 20% (3/15) for S. aureus, 20% (3/15) for E. coli and 13.3% (2/15) for P. aeruginosa; the proportion of isolates inhibited by Haemolymph B were 33.7% (5/15) for E. coli, 26.7% (4/15) for S. aureus and 13.3% (2/15) for P. aeruginosa. For both Haemolymphs A and B extracts, S. aureus had the largest mean diameter zone of inhibition of 19.00±3.61mm and 22.25±2.63 respectively. E. coli had the smallest mean diameter for Haemolymph A (13.67±3.22mm) while P. aeruginosa had smallest mean diameter for Haemolymph B (16.00±5.66mm). For each of the three bacterial pathogens, there was no significant difference in the proportion of isolates inhibited by Haemolymph A and Haemolymph B or the mean zone sizes of inhibition (p> 0.5).

Conclusion: Haemolymph of Achatina achatina exhibits antibacterial activity against multi-drug resistant isolates of S. aureus, P. aeruginosa and E. coli. However, there is a high tendency for multi-drug resistant bacterial isolates to be haemolymph-resistant. The antibacterial effect of haemolymph extracts from Achatina achatina snails appear to be consistent.

Aims: To investigate the effects of silver nanoparticles on the flexural strength of three commercial heat-cure denture base materials such as Lucitone199, Trevlon, and TriplexHot.

Methodology: A total of 150 specimens were fabricated and assigned equally among the three selected denture base resin products. Samples in each denture base resin product were distributed among control, 0.5 wt%, 1.0 wt% 2.0 wt% and 5.0 wt% AgNPs added to the acrylic powder prior to the processing. Specimens without silver nanoparticles are considered as control group. Flexural strength was measured using three point bending method using universal testing machine at a crosshead speed of 2 mm per minute.

Results: One way ANOVA and Tukey HSD tests were used to analyse the results. Control group exhibited superior flexural strength whereas flexural strength of the specimens decreased with the increasing concentration of silver nanoparticles.

Conclusion: Incorporation of silver nanoparticles decrease the flexural strength of heat cure denture base materials and the flexural strength was influenced by the concentration of nanoparticles.

The diversity of arbuscular mycorrhizal fungi (AMF) was examined in the cut and filled slopes of Taza region (North-East of Morocco). The identification of the spores isolated from these two types of slopes has revealed 29 species belonging to 7 genera: Glomus (14 species), Acaulospora (6 species), Gigaspora (2 species), Pacispora (3 species), Entrophospora (2 species), Scutellospora (1 species), Funelliformis (1 species), 6 families (Glomeraceae, Gigasporaceae, Acaulosporaceae, Pacisporaceae, Scutellosporaceae, Entrophosporaceae) and 3 orders (Glomerales, Gigasporales, Diversisporales). The number of specific species to cut and filled slopes is respectively 12 and 6 species and the number of species common to the two types of slopes is 11 species. All these species will serve, after multiplication, as sources of endomycorrhizal inoculum, which can enhance the growth and increase the resistance of plants, used for vegetation and restoration of the slopes.

The effects of salicylic acid (SA), glyphosate (Gly) and interaction of SA + Gly on seed germination and seedling growth, leaf morphology, cell ultrastructure and physiological alterations of Vicia faba plants were evaluated. SA (50 and 100 µM) reduced root seedling growth. Exposure to 250 and 500 µM Gly with or without SA caused an inhibition in seed germination and seedling growth of V. faba plants. Chlorosis, necrosis, welting, and growth reduction of V. faba was noticed in response to Gly and SA + Gly treatments. The photosynthetic pigment (Chlorophyll a (Chl a), Chlorophyll b (Chl b) and carotenoid (Car) contents of glyphosate and SA + Gly-treated plants were declined compared to the control. Electron microscopic observations of glyphosate-treated plants revealed disorganization in the internal structure of chloroplasts. Formation of vesicles within chloroplasts was observed in glyphosate and interaction of SA + Gly-treated plants. The lamellae and stroma thylakoids of chloroplasts were degenerated. Contents of soluble proteins and total phenolic compounds were decreased in glyphosate and SA + Gly-treated plants compared to the control. Peroxidase (POX) activity significantly increased with application of SA and glyphosate as well as with the interaction of SA + Gly compared to the control. Malondialdehyde (MDA) content in glyphosate and interaction of SA + Gly-treated plants increased compared to untreated one. The obtained results indicate that the root seedling growth of V. faba is sensitive to SA and Gly, while shoot was only sensitive to Gly herbicide treatments. The vegetative growth, cell organelles and physiological functions was negatively affected by Gly. Application doses of SA appear to be did not alleviate the toxicity of Gly herbicide on V. faba.