A new nanobiotic: synthesis and characterization of an albumin nanoparticle with intrinsic antibiotic activity.

Background and Objectives: With entering the "post-antibiotic era", antibiotic resistance is one of the most important problems in food security, health and medicine. Invention of nanoparticles with intrinsic antimicrobial activity has been provided a new tool to combat the problem, including some metal nanoparticles. But protein nanoparticles have been often used as nano-carrier for antibiotic drugs, not for their own antibiotic activity. In this article we have fabricated a very small BSA-NP without any chemical modification on BSA molecules showing antibacterial activity. Materials and Methods: Bovine serum albumin nanoparticle (BSA-NP) was synthesized using botton-up approach, by dissolution of BSA in urea-containing Tris buffer for 60 min at 60°C. Then, the BSA solution was dialyzed against distilled water in order to nanoparticle formation. The resulted BSA-NP has been characterized by dynamic light scattering (DLS), field emission surface electron microscopy (FESEM), SDS-PAGE, Fourier transform infrared spectroscopy (FTIR) and UV-spectrophotometery. Minimum inhibitory concentration (MIC) method was used for evaluation of antibacterial activity of BSA-NP against Staphylococcus aureus and Pseudomonas aeruginosa. Results: The results obtained by DLS technique indicated that BSA molecules were self-assembled into small aggregates with a hydrodynamic diameter of 23.23 ± 2.1 nm. With a small polydispersity index (PDI=0.522), the nanoparticles had good spherical uniformity. The nanoparticles made from a single type of protein molecule (BSA) and have a relatively transparent appearance. The BSA-NPs caused a decrease in cell growth of both P. aeruginosa and S. aureus. Moreover, they had a bacteriostatic effect on P. aeruginosa (MIC=112×10-5 µM). Conclusion: In this study, using a green synthesis method, we succeeded in synthesizing a very small uniform BSA nanoparticles without any chemical modification on BSA molecules. It also has bacteriostatic properties against P. aeruginosa. Therefore, it is hypothesized that our BSA-NPs may be effective as a new approach to combat antibiotic resistance.

Irreversible thermal inactivation and conformational lock of alpha glucosidase.

In the present work, we studied the structure-activity relationship and kinetics of thermal inactivation of α-glucosidase A (AglA) in a 50 mM potassium phosphate buffer at pH 6.8 using p-nitrophenyl α-d-glucopyranoside (pNPG) as the synthetic substrate following absorbance at 410 nm by UV-Vis spectrophotometer. The interface structure and residual activity plot were analyzed via biochemical measurements by means of conformational lock theory, as well. The thermal inactivation curves were plotted in temperature interval from 30 to 50 °C. Based on experimental and structural data we suggested intermediates during inactivation before the loss of enzyme activity. Arrhenius plot for thermal inactivation rate constant showed biphasic appearance related to before and after 45°C temperature. The contact areas between two subunits were ruptured and unlocked stepwise during dimer dissociation. Cleavage of these areas induced the dissociation of the subunits along with destruction of the active centers and subsequently the loss of activity. It seems that the contact areas interact with active centers by conformational changes involving secondary structural elements.

Antibacterial Activity of Semenovia suffruticosa (Essential Oil) Against Pathogenic Bacteria and Determination of Chemical Composition of Essential Oils by Gas Chromatography-Mass Spectrometry Analysis in Four Regions of Kerman.

The use of medicinal plants has been considered due to increasing bacterial resistance to antibiotics. Semenovia suffruticosa is a plant with high potential in medicine. The aim of this study was to evaluate the antibacterial activities and gas chromatography-mass spectrometry (GC-MS) analyses of the essential oil of S. suffruticosa from four regions in Kerman: Hezar Mountain, Laleh Zar, Bidkhan, and Rabor. The essential oil of this plant was extracted by Clevenger. The antibacterial activities were evaluated against three Gram-negative bacteria (P. aeruginosa, K. pneumonia, Acinetobacter) and three Gram-positive bactria (B. subtilis, S. aureus, S. pneumoniae). By disk diffusion method, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values were determined. The composition of essential oil was identified by GC-MS analysis. In our study, most yield of essential oil of S. suffruticosa was 1.2% from the Laleh Zar region and the main components were Z-ß-ocimene (25.4%) in Laleh Zar, linalool (17.7%) in Hezar, Z-ß-ocimene (18.5%) in Bidkhan, and ß-pinene (10.5%) in the Rabor region. Maximum inhibition zone by the essential oil from region Bidkhan was observed against K. pneumoniae (30 mm). The MIC value for S. suffruticosa collected from Laleh Zar was 1.25 mg/ml against S. aureus and S. pneumonia. The results of this study confirm that the significant antibacterial effects of S. suffruticosa and make it a valuable compound in essential oils for pharmaceutical use and a good replacement for chemical antibiotics. Environmental conditions can result in a difference in yields and components; this can be considered significant potential for this plant.