نشریه دانش زیستی ایران
سال هفدهم شماره 4 (زمستان 1401)

Cerium oxide nanoparticles (CeO2 NPs) are one of the most widely used NPs in the world and their interaction with the ecosystem is unavoidable. The aim of this study was to investigate structural and ultrastructural changes in marigold leaves under CeO2 NPs. Seeds were sown in pots under greenhouse conditions and after two weeks, seedlings were exposed to CeO2 NPs (0 and 3200 μg/mL) by leaf spray for five weeks. Then, leaf morphological changes were measured. Also, sampling from the control and NPs treatment leaf were performed to investigate structural and ultrastructural changes. Tissue preparation was performed and samples were examined by light and transmission electron microscopy (TEM). Morphological changes including diminish in the length, width and area of marigold leaf under CeO2 NPs were observed. Also, ultrastructural changes of mesophilic cells of marigold leaf under CeO2 NPs including diminish of chloroplasts number and their swelling, incement of peroxisomes number, disintegration of cell membrane, and accumulation and deposition of NPs in the intercellular spaces, cell wall and membrane, vacuole, peroxisome and chloroplast stroma were observed. In addition, the results of cerium elemental assessment by methods of inductive coupled plasma emission spectrometry (ICP-OES) and energy dispersive X-ray spectroscopy (EDX), in line with TEM results, showed the uptake and accumulation of CeO2 NPs in marigold leaves. Ultrastructural damage in TEM results indicated the toxicity of high dosage of CeO2 NPs at the cellular level. Therefore, potential of hazardous impacts of CeO2 NPs on other medicinal plants and environment should be considered.

Due to the importance of disinfection and prevention of diseases caused by Escherichia coli, sometimes the companies producing these disinfectants have exaggerated and it causes the employees of health centers and hospitals to use these products as sterilizers to sterilize surfaces and places without conducting tests. If these products do not have the recommended efficiency and effectiveness mentioned in the instructions of the manufacturer, it will cause irreparable losses. This study was carried out in 1400 with the aim of evaluating the effect of three disinfectants Microten, Benzalkonium Chloride, and Savlon with recommended dilutions on Escherichia coli isolates from general hospital wards. In this study, 50 samples were collected from the general departments of the hospital, and E.coli were analyzed using biochemical and molecular methods. E.coli (G4S45) was used as a control. Bacteria were cultured using the pour plate method using the pharma dilution method according to the American USP standard. Finally, the effect of the mentioned disinfectants on E.coli was investigated. 19 samples were positive for the presence of E.coli and three disinfectants were in 5, 10, and 15 minutes after incubation, and performing the pour plate method caused a 100% lack of growth.  the efficiency of the three tested disinfectants was 100% effective according to the manufacturer's instructions.

High temperature causes oxidative stress in the body of animals. Selenium is a trace mineral that affects the health and performance of the body in stressful conditions. There are limited studies on the effects of different doses of selenium in long-term heat stress conditions on physiological parameters and health indicators. This study was conducted to determine the effects of different doses of selenium from selenium-methionine supplement on the antioxidant status (glutathione concentration, activity of superoxide dismutase and glutathione peroxidase), liver and kidney health index (the activity of transferase enzymes and creatinine concentration) and concentration of metabolism-related hormones (insulin, cortisol, triiodothyronine and tetra-iodothyronine). In a completely randomized design, 25 female rats were randomly divided into five groups and five replicates. Five rats were placed at standard temperature during the experiment period and the rest of the rats were placed under heat stress (38 ± 2 °C for 6 hours/day). Rats in the negative control group (without heat stress) and positive control (heat stress) were fed with standard pellets without additive and the other three groups were fed with standard pellets plus 0.15, 0.30 and 0.45 mg selenium/kg as a selenium-methionine supplement for 30 days. Rats receiving selenium had more hemoglobin and alanine transaminase enzyme activity (P=0.001) compared to the positive control group. Cortisol concentration in the positive control group was higher than the negative control group (P=0.001). Adding selenium to the diet of rats under heat stress decreased (P=0.001) the concentration of cortisol, and increased the concentration of insulin and triiodothyronine compared to the positive control group. The serum malondialdehyde of the positive control was higher than the negative control and other experimental groups (P=0.001). According to the results of this study, heat stress causes oxidative stress in the body and causes changes in the hormonal concentration and the activity of the body's enzymes. In overall, it can be concluded that higher selenium supplementation (0.45 mg/kg) is optimal for improving the liver and kidney indices, hormone concentration and antioxidant response in rats under heat stress conditions.

Tamarix is the largest genus in the family Tamaricaceae with about 54 species.Taxonomically due to interspecific hybridization the number of Tamarix species in the world and in Iran is discussed. the purpose of this research study of Taxonomic and morphological diversity of 51 samples of 10  species are related to different regions of Iran. 9 Characters (4 quantitative, 5 qualitative) of the morphological structure of vegetative and reproductive organs of the species were studied and statistical analysis was performed. Such as the characteristics of the number of petals, the number of sepals, number of stamen rows, outer sepal, inner sepal, external sepal tip shape, ttachment of stamen to lobe, bracte length relative to calyx length, number of stamen They are one of the prominent morphological features of this genus. PCA showed the most variance in two main components. PCA biplot was drawn to show the most variable traits in morphological studies. Also, clustering method were drawn in morphological studies to show the separation of boundary between species. The borders of all species were separated by the mentioned morphological traits and only boundary of T. karakalensis, T. korolkowii, T. ramosissima were not separated due to overlap in bracte length relative to calyx length character.The information obtained is consistent with the results of molecular studies with the SCoT marker previously performed. The present study indicates the presence of morphological diversity in species and even between individuals of species in Iran. It also showed that morphological traits with molecular studies are effective in determining the boundary of species

Suspended particles contain polluting heavy metals present in industrial areas adjacent to residential areas and negatively affect residents' health. The main goal of this research is to sample and determine the concentration of suspended particles and heavy metals in the autumn season of 2021 in the air of the 21st district of Tehran. The sampling method is according to ASTM and EPA standards, 20 active samples were taken from residential, semi-residential, industrial, semi-industrial and park uses by a high-volume pump in the autumn season. The findings show that the average concentration of TSP in the stations of region 21 in the cold season is an increasing trend in 5S (  = 99.71), 2S (  = 124), 1S ( = 144.21), 3S (  = 173.10) and 4S (  = 220/37). The average concentration of HM10 in the whole region 21 is in the order of increasing Al>Cr>Zn>Fe>Mg>Pb>Sr>W>Ti>Li. The findings show that among all the elements, aluminum has the highest concentration with 89.65 µg/m3 in industrial use, 78.72 µg/m3 in semi-industrial use, 68.98 µg/m3 in semi-residential use, 55.76 µg/m3 in residential use, 41.65 µg/m3 in garden use. Also, lithium element has the lowest concentration in all stations. Determining the concentration of suspended particles and heavy metals helps urban planning officials in prioritizing and controlling air pollutants.

The development of nanotechnology in the last decade has opened a new and unique window to science; Among them, silver nanoparticles are one of the most important types of nanoparticles due to their antimicrobial properties. There are different methods for producing silver nanoparticles by green synthesis. Using plant extracts to produce silver nanoparticles is a cheap and cost-effective method that does not harm the environment.

In this research, the phytochemistry of the plant and the production of silver nanoparticles using the leaves of )Eryngium pulegium( were studied. Also, the antibacterial effect of the resulting nanoparticles was investigated on Escherichia coli and Staphylococcus aureus bacteria.

First, secondary metabolites including phenol, flavonoids, terpenoid and alkaloids were measured. Then, the amount of antioxidant activity of Chuchag) Eryngium pulegium) plant extract was measured by DPPH method and after confirming the presence of antioxidant property and high amount of secondary metabolites in the examined plant, the synthesis of silver nanoparticle was carried out by aqueous extract of Chuchag plant)Eryngium pulegium( and by spectrophotometry and SEM methods. TEM confirmed the presence of nanoparticles and determined the size and shape of nanoparticles. Then, the antibacterial property of the extract along with nanoparticles was evaluated on two species of bacteria, Escherichia coli and Staphylococcus aureus.

The analysis of secondary metabolites in (Eryngium pulegium) plant showed that the main and indicative compounds in (Eryngium pulegium) essential oil include terpenoids curcumin, gamma-3 carne, beta gorgonen, alpha guain, gamma cadinene, alpha terpinen, etc. The results of LC.MS of alkaloids showed that Eryngium pulegium has 4 alkaloid compounds in order of highest concentration, berbamine, coxoline, balochistin and fikamin. The results related to DPPH in (Eryngium pulegium) plant showed that as the concentration of ( Eryngium pulegium) extract increased, its free radical inhibition percentage also increased, so it can be proved that Eryngium pulegium has free radical inhibitory properties. It also has antioxidant properties. Vis-UV spectroscopic analysis and the presence of a peak at 370 nm indicated the biosynthesis of these nanoparticles in (Eryngium pulegium) extract, and the SEM image determined the shape of the nanoparticles to be spherical and their average size around 20 nm. In the investigation of the antibacterial effect of nanoparticles biosynthesized with (Eryngium pulegium) extract against microbial bacteria, the nanoparticles showed a good antibacterial effect against the studied bacteria. In the MIC test on Staphylococcus aureus bacteria, the minimum inhibitory concentration in(Eryngium