نشریه بیولوژی کاربردی
سال هشتم شماره 4 (پیاپی 32، زمستان 1397)

Listeria monocytogenes has been isolated from many foods and may cause meningitis, septicemia and abortion in pregnant women. L. monocytogenes forms biofilm on many food contact surface materials and medical devices. Biofilm formation by this bacterium on many surfaces, is one of the most important problems in the food industry. Metal nanoparticles are effective antimicrobial compounds for controlling and removing of bacterial biofilms from non-biomaterial surfaces. The main purpose of this investigation was synthesis of silver iodide nanoparticles in-vitro condition and evaluation of their antimicrobial properties for inhibition of biofilm formation and biofilm eradication of Listeria monocytogenes(ATCC1298).

In this study nano-particles of silver iodide were synthesized respectively sonochemically and were confirmed using UV-Vis ,FTIR, EDX and Scanning Electron Microscopic procedures. Antimicrobial and antibiofilm properties of synthesized nanoparticles were determined using agar well diffusion and 96 well microplate dilution methods respectively.

Synthesized Silver nanoparticles had circular structure with 30 nm size. Antibiofilm activity and biofilm eradication of Iodide silver nanoparticles were obtained at 5 and 100 µg/ml respectively.

Based on obtained results, silver iodide nanoparticles can be used as the effective antimicrobial agents for inhibiting of biofilm formation of Listeria monocytogenes in the food industry.

In order to investigate the effect of Azolla compost on vegetative characteristics of ornamental plants, Pedilanthus tithymaloides was selected as a model plant. In this regard, an experiment was conducted as a completely randomized design in five treatments and three replications in the Advanced Greenhouse of the Research Institute of Biotechnology, Rasht. The Growing media control of this study, peat-perlite-sand, was considered 1: 1: 1 ratio, and the compost Azolla was replaced by 0%, 25%, 50%, 75% and 100% volumes. The treatments consisted of: Azolla compost + 100% Peat-perlite-sand (control), Azolla compost + 75% Peat-perlite-sand, 50% Azolla compost + 50% Peat-Pearlite-Sand, 75% Azolla compost + 25% Peat-perlite-sand and 100% Azolla compost + 0% Peat-perlite-sand. In this experiment, growth indices, including number of leaves, number of buds, length of bud, fresh and dry weight of stem, fresh and dry weight of root were measured. The results showed that replacing Azolla compost levels had a significant effect on leaves number, length of bud, fresh and dry weight of stem, fresh and dry weight of root. Comparison of the substrate used showed that replacement of 25% Azolla compost in the Growing media had the most effect on Pedilanthus plant growth indices.

Klebsiella pneumoniae is a germ-negative pathogen and a common cause of nosocomial infections. Increasing the emergence of multi-drug resistance in Klebsiella pneumonia has limited therapeutic options for this bacterium. The purpose of this study was to evaluate the effect of iron nanoparticles on expression of TEM and SHV genes in Klebsiella pneumoniae isolated from clinical samples using Real- Time PCR.

A total of 50 strains of Klebsiella pneumoniae were collected from patients admitted to the intensive care unit of hospitals in Kerman on 6 months. The isolates were identified as K. pneumoniae, based on the biochemical tests embedded in the API-20E system. Antibiotic susceptibility test was performed by disc diffusion method. For molecular identification of TEM and SHV genes, PCR was performed. To determine the effect of iron nanoparticles on the strains, a dilution broth method was used according to CLSI standard and finally, Real-Time PCR was performed.

In this study, 46 isolates were positive for ESBL producing phenotypes. In the 46 isolates of ESBL producing, 48% (22 cases) had the SHV gene , 13% (6 cases) had the TEM gene and 39% (18 cases) had both SHV + TEM genes. Iron nanoparticles could degrade the expression of TEM and SHV genes in the clinical medium in Klebsiella pneumoniae.

Due to the effectiveness of iron nanoparticles on positive beta-lactamases Klebsiellas, can use iron nanoparticles as a medicine dose.

Staphylococci are rapidly resistant to most antibiotics and cause many therapeutic problems. Of these, the efflux pumps are the most important cause of resistance to antibiotics, and these pumps are the core of the inherent inflammatory system of the nor gene. Staphylococcus aureus, norA, norB, and norC are chromosomal genes that encode these pumps, expressing high levels of multi-drug resistance genes can produce resistance to quinolones. The purpose of this study was to investigate the presence of norA B, C genes in the presence of germs in the isolates of Staphylococcus aureus isolated from the samples of urinary tract infection. In this study, samples from 300 urine samples of patients referred to the laboratories in north of Tehran were collected and identified 100 samples of Staphylococcus aureus. After identification of resistant strains of fluoroquinolone family antibiotics, DNA extraction was performed to confirm the presence of norA, norB and nor C genes by PCR reaction. The results were analyzed by electrophoresis on agarose gel. Of the 100 isolated isolates of Staphylococcus aureus, 60 isolates were resistant to the ciprofloxacin disc, 30 isolates were resistant to neurofloxacin and 10 isolates compared to furosemide. Of the 100 isolates, 30 isolates possessed a norB resistance gene, 20 had norC gene and 20 had norA gene. Also, 10 isolates containing all three genes and 15 isolates, had 2 genes from the 3 genes studied.

This plant Verbascum cheiranthifolium Boiss. belonging to the Scrophulariaceae family, is derived from traditional Iranian medicine and vicinal countries which is used both edible and topical for treatment. For the first time in this research the amount of total phenol, Flavonoid and antioxidant property of aerial parts extract of plant of Iran in the Kolakchal area (Tehran-Iran) were investigated. To measure The amount of Phenol and Flavonoid respectively is used from reagents Folin- Ciocalteu and Alcl3 and the method DPPH is used to measure the Antioxidant potential. The result showed the phenolic content for samples respectively 0.925 milligram of galic acid per gram dry weight and 18.887 milligram quercetin per gram dry weight. In evaluation of antioxidant potential by method DPPH amount of Ic50 for BHT 72301/428 µgr/ml and for the extract is 45829/364 µgr/ml. As a result, the antioxidant activity of this plant have higher potential against the antioxidant synthesis of BHT. The results of this study showed that this plant has a good antioxidant power against a variety of oxidative systems and as an accessible natural antioxidant can be used in food and pharmaceutical industries.

In recent years there has been development of non-conventional and underexploited promising plant species as new sources of oils. Many of them contain significant quantities of oils with high proportion of nutritionally, medicinally or industrially desirable fatty acids.Tobacco seeds, grown in the north of Iran, were investigated in this study. The oil, ash and water contents of tobacco seeds alongwith fatty acid composition, acid value, iodine value, peroxide value, saponification value, p-anisidine value, density, viscosity, refractive index, oxidation stability, differential scanning calorimetric and thermogravimetric profiles, UV-Vis, FT-IR, Fluorescence spectra, phenolic compounds and antioxidant activity of the extracted seed oil were analysed. The results showed that the tobacco seeds contained a high amount of oil (~40%). The three major fatty acids in the tobacco seed oil were linoleic (71.35%), oleic (14.57%), and palmitic (8.67%) acids. Tobacco seed oil showed absorbance in the UV-B and UV-C ranges with potential for use as a broad spectrum UV protectant. Tobacco seed oil showed high kinetic stability, as characterized by differential scanning calorimetry. Total phenol content of tobacco seed oil was also higher compared with soybean, falx seed and corn oil. According to the IC50 value (0.438 g/ml), tobacco seed oil can be categorized as an oil with considerable antioxidant potential. This study reveals that tobacco seed oil has a high level of functional lipids and can be used as a new source of oil in different applications.

Because the role of essential oils and aromatic substances in plants is lost due to chemical evaporation or chemical instability over time, Many methods have been used to increase the stability and durability of essential oils, and encapsulation is one of the most important ones. In this study, micro or nanocapsules containing mint essential oil were prepared by coacervation and freeze drying methods using various polymers such as sodium alginate, starch and malto dextrin. Initially, with different weighing of each of the polymers, solutions were prepared with deionized water to achieve the best concentration. The ultrasound homogenizer was then used to homogenize, and the mint essence was gradually added to the homogeneous solution. The capsules were prepared immediately after preparing homogeneous polymer and essential oil mixtures. After that, the capsules were evaluated by scanning electron microscopy(SEM). The type of polymer, polymer concentration and mixing speed are among the factors affecting the type of capsule and how the mint essence is released.