Synthesis and characterization of microbial mediated cadmium oxide nanoparticles.

Microbial mediated synthesis of metallic nanoparticles constitutes as effective and promising approach for the development of antibacterial materials in the field of bioengineering and biomedicine. We prepared Cadmium oxide nanoaprticles (CdO NPs) utilizing Penicillium oxalicum, and cadmium acetate solution via coprecipitate method. The elemental composition and morphology of these synthesized CdO NPs were examined through X-ray diffraction (XRD), UV-Vis absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and Energy dispersive spectroscopy (EDS). Furthermore, we evaluated the bactericidal potential of prepared CdO NPs using Escherichia coli (E.coli), Staphylococcus aureus (S.aureus), Bacillus cereus (B.cereus), and Pseudomonas aeruginosa (P. aeruginosa). Dimethyl sulfoxide was used as negative control while erythromycin was used as positive control. The XRD spectrum revealed cubic crystalline nanoparticles with 22.94 nm size and UV showed absorbance peak at 297 nm with 2.5 eV band gap energy. FTIR depicted O─H and carboxylic groups along with CdO stretching vibration. EDS showed the presence of organic compounds on Cd and O over NPs surface. SEM results revealed the spherical shape of the CdO NPs. The synthesized NPs exhibited highly potent bactericidal activity against selected strains and demonstrated less optical density of 0.086 after 24 hr. Owing to the significant antibacterial activity of CdO NPs, the broad application prospects of these nanoparticles CdO NPs in extensive biomedical applications is indicated.

Foliar micromorphology and its role in identification of the Apocynaceae taxa.

In the present study, we evaluate the importance of foliar epidermal micromorphological characteristics of Apocyanaceae for accurate identification and classification. The species were collected from the University of Peshawar's main campus in the spring season to observe its qualitative and quantitative features. The length and width of guard cells, stomatal pore and subsidiary cells, trichomes, and crypts on both sides of the leaf were examined. Many species were observed to be hypostomatic. Plumeria rubra, Raulfia serpentine, Thevetia peruviana, Trachelospermum lucidum, Alstonia scholaris, and Catharanthus roseus demonstrated hypostomatic leaves. Nearly all the investigated species had anisocytic type of stomata only or in combination with other types of stomata on the upper and lower epidermis. Carissa carandas had anomocytic, anisocytic, and cyclocytic type of stomata on the upper epidermis, and the lower epidermis showed variations in stomatal type, such as anomocytic, stephanocytic, brachyparacytic, and hemiparacytic. Nerium oleander had no specific shape of stomata but showed stomatal crypts in which the stomata were enclosed inside many trichomes. The taxonomic key based on stomatal types, epidermal cells, stomatal index value, and statistical analysis, along with the variations in the epidermal cells, shows the link between the selected plants species, which will provide a baseline for future anatomical studies. This study highlights many undocumented micromorphological characteristics. The anatomical characteristics observed in this study will be helpful for taxonomic identification and species delimitation of the family Apocynaceae.

Characterization and phytostimulatory activity of bacteria isolated from tomato (Lycopersicon esculentum Mill.) rhizosphere.

Replacing agrochemicals with plant growth promoting bacteria (PGPB) may offset some of the environmental impacts of food production. The objectives of this study were to (1) isolate and characterize bacterial strains from tomato rhizosphere, including root, shoot and leaf, (2) select and identify the most promising PGPB strains, (3) verify the phytostimulatory activity and mineral uptake potential of selected strains. Bacterial strains isolated from tomato rhizosphere, were screened for phosphorous (P) solubilization, production of indole acetic acid (IAA), amylase activity, antibiotic resistance, and quick test strip (QTS) for biochemical characterization. The tested strains, positive for all five of these assays were selected for molecular identification and subjected to greenhouse growth trails with tomato and mung bean. Two strains were selected and identified as Bacillus cereus (B. cereus) isolated from rhizosphere and Klebsiella variicola (K. variicola) isolated from root endosphere using 16s rRNA sequences. Both strains produced IAA, gibberellic acid (GA3) and kinetin, however B. cereus showed potential GA3 and IAA production as compared to K. variicola. In tomato, only one growth variable (shoot length) was increased over the control by one of the selected bacterial strains (B. cereus). In mung bean, inoculation with either strain B. cereus or K. variicola increased shoot length and dry weight. Moreover, our results showed that the use of PGPB significantly increased plant growth and Fe, Zn, Ca, Mg, Cu, Na and K contents of plants. It seems that evaluated strains had a higher ability in boosting plant growth and higher yield.