جستجوی مقالات مرتبط با کلیدواژه "سمیت" در نشریات گروه "زیست شناسی"

The present research was conducted in order to investigate the negative effects caused by the accumulation of heavy metals (HMs) in fish as well as the human body, which occurs due to the long-term consumption of contaminated fish. The investigation of various sources of HMs showed that agricultural and industrial activities have a major contribution to the presence of various metals such as cadmium (Cd), nickel (Ni), lead (Pb), arsenic (As) and mercury (Hg) in water environments. With the continuous entry of these toxic substances into aquatic ecosystems, the possibility of bioaccumulation of heavy metals in the body of various aquatic animals, especially fish, is provided. Bioaccumulation of HMs by fish and their subsequent distribution in body organs among different species is significant. Several factors such as sex, age, size, reproduction cycle, swimming pattern, feeding behavior and geographical location can affect the absorption of HMs and their bioaccumulation in the body of fish. A literature review showed that most heavy metals are toxic to the body at very low levels. However, among different metals, Hg, Pb and Cd have a higher degree of toxicity. Among the toxicity mechanisms of these metals, we can mention the production of free radicals, which is done in order to create oxidative stress. In addition, damage to biological molecules such as proteins, lipids, enzymes and nucleic acids, as well as DNA damage, also show an important part of the toxicity mechanism of HMs. According to the findings, an increase in the concentration of Hg, Pb and Cd in fish tissue compared to other HMs can have much more harmful consequences on the health of society. Therefore, it is necessary to pay more attention to the effects caused by bioaccumulation of these metals in the fish body and the possibility of their transfer to the human body through the food chain.

In the current study, the toxicity of zinc oxide nanoparticles (ZnONPs) and zinc sulfate (ZnSO4) in Hypericum perforatum L. pre-treated with salicylic acid and nitric oxide (sodium nitroprusside) at a concentration of 0.1 mM was investigated in a completely randomized design with three replicates as pot culture in perlite. After 21 days of treatment, the plants were harvested. The results of the variance analysis of the data in the laboratory showed that the application of 1000 mgL-1 of zinc oxide or zinc sulfate nanoparticles caused more toxicity. However, the greatest effect is related to the pretreatment of salicylic acid and nitric oxide (sodium nitroprusside), which successfully reduced the value of the oxidative stress index (malondialdehyde) and as a result, the adverse effect of zinc on the seed germination of gerbera. The combination of salicylic acid and nitric oxide increased the amount of proline in the treatment of zinc oxide nanoparticles and phenol antioxidants had a significant increase under the effect of zinc oxide nanoparticles and zinc sulfate, which was associated with an increase in the activity of the phenylalanine ammoni alyase enzyme. The amount of zinc in the roots also increased with the combination of salicylic acid and nitric oxide under the stress of zinc oxide nanoparticles. In this research, it was tried to minimize the negative effect of zinc oxide nanoparticles and zinc sulfate on plant products by designing new methods.

Nanoparticles due to their wide applications in medicine,industry,and biotechnology, have attracted many scientists’ attentions. Recently, nanoparticles especially selenium nanoparticles are widely used to diagnosis and cancer treatment. The aim of this study was to evaluate the cytotoxic and anticancer effects of selenium nanoparticles on colon cancer cell line and analysis of CAD (Caspase Activated DNase) gene expression.

In this study, colon cancer HT29 and normal HEK293 cell lines were purchased from the Pasteur Institute Cell Bank of Tehran and treated with selenium nanoparticles overnight. The cells were cultured in Dulbecco’s Modified Eagle’s Medium (DMEM) (Gibco, Scotland) medium with 10% FBS serum and 1% streptomycin antibiotic (Gibco, Scotland). The cells were then stored at 37 ° C. In this study, cytotoxic effect of Selenium NPs was evaluated on HT29 and HEK293 cells using MTT (3-(4, 5-Dimethyltetrazollium Bromide) assay. Subsequently, they were treated with selenium nanoparticles in different concentrations (0, 7.81, 15.62, 31.25, 62.5, 125, 250 and 500 mg/mL) for 24 hours. To solubilize the viable cells formazan crystals production, we added 100 μl/well of dimethyl sulfoxide (DMSO) to them. After treatment of HT29 cells with IC50 concentration, the total RNA was extracted and cDNA synthesized. Moreover, CAD gene expression was evaluated using Real Time PCR method. The data was evaluated by ABI StepOne utilizing the Applied Biosystems qRT-PCR (ABI 7300 system, Applied Biosystems). The quantification of the mode of Selenium NPs -induced cell death in the HT29 cells were ascertained using flow cytometry followed by staining with fluorescein isothiocyanate (FITC)‐Annexin V and propidium iodide (PI) staining. Finally, the study of apoptosis and necrosis of Selenium NPs was evaluated using flow cytometry method. Data analysis was statistically determined by using One-way analysis of variance (ANOVA) with SPSS/22 software followed by a Tukey test.

The result showed that the treatment of Selenium NPs at 31.25 to 500 µg/mL concentration had maximum cytotoxic effect, revealed statistically significant (P˂0.001). The IC50 value for Selenium NPs were measured at 75 µg/mL after 24 hours. In order to determine the effect of Selenium NPs on cancerous cells, alterations in the mRNA expression levels of CAD gene in HT29 cells were done by qRT-PCR technique followed by the exposure to nanoparticle. The CAD gene expression comparing to reference gene was up-regulated 4.04±0.125 fold. To determine the mechanism of cell death in the cancer cells, annexin V/PI flow cytometry was carried out. In the treatment of HT29 cells by IC50 of selenium NPs, 10.43%, and, 24.28% of early and late stages’ apoptosis were observed, respectively

Our results suggest that selenium NPs can display some promising cytotoxic properties through inducing apoptosis pathway. Based on the results, up-regulated gene expression involved in apoptosis (CAD) and activating apoptosis, it can be concluded that the selenium NPs can be used as drug candidate in colon cancer treatment, but more studies are needed regarding the medicinal importance of nanoparticles.

In order to investigate the effect of biochar and selenium on the quantitative and qualitative characteristics of coriander (Coriandrum sativum L.) under cadmium stress, a factorial experiment was conducted in the form of a completely randomized design with three replications in greenhouse conditions during the years 2022. The experimental treatments include the use of cadmium chloride at three levels (0, 10 and 20 mg/kg), biochar at two levels (0 and 5% of soil) and foliar spraying with sodium selenate at two levels (0 and 20 mg/l). The results of this research showed that cadmium treatment of 20 mg/kg caused a decrease in fresh and dry weight of shoot and root, chlorophyll a, b and total, relative leaf water content and increased activity of superoxide dismutase enzyme and soluble sugar. Phenol increased up to the cadmium level of 10 mg/kg, but decreased at higher cadmium levels (20 mg/kg). By reducing the effect of cadmium stress, selenium and biochar treatments increased the fresh and dry weight of roots and shoots, chlorophyll content, relative leaf water content, and essential oil yield, and decreased the characteristics of superoxide dismutase enzyme activity, soluble sugar, and cadmium accumulation in roots and shoots. The highest amount of essential oil yield (16.93 mg/plant) and percentage of essential oil (0.44%) was observed in the combination treatment of biochar 5% by volume and selenium 20 mg/l. Biochar and selenium improved coriander traits by modulating the effect of cadmium stress.

The study aimed to examine the chronic toxicity effects of oxytetracycline (OTC) and florfenicol (FLO) antibiotics, commonly used in shrimp farms, on the growth performance, chlorophyll a content, and total protein of Chaetoceros muelleri microalgae. C. muelleri, initially at a density of 4,000 cells per milliliter, underwent exposure to oxytetracycline at doses of 7.43 milligrams per liter and florfenicol at 5.20 milligrams per liter for 12 days. Subsequent assessments focused on growth metrics, chlorophyll a content, and total protein. The findings highlighted a significant reduction in the growth, chlorophyll a content, and protein synthesis of C. muelleri following exposure to both OTC and FLO antibiotics (p < 0.05). Moreover, the study revealed that FLO exhibited higher toxicity toward C. muelleri compared to OTC. The observed decline in growth, chlorophyll a content, and protein synthesis in C. muelleri under OTC and FLO exposure could be attributed to the inhibitory impact of these antibiotics on cellular respiration and protein synthesis pathways.

Skin is a soft tissue that protects the whole body and internal tissues against external hazards such as burns or injuries. Risks cause loss of the skin's defense mechanism and severe infections and wounds that inhibit the healing. Therefore, it is very important to develop effective and fast skin repair. The aim of this study was to prepare a porous scaffold for wound covering made of Polycaprolactone (PCL), the core of this scaffold is made of Carbon Quantum Dot (CQDs), Iron nanoparticles (Fe), and Chitosan (Cs).

The composition of Fe-CQDs was synthesized by ammonium-hydrogen-citrate under hydrothermal conditions and Poly capro lactone/Chitosan/Carbon-quantum dot-iron scaffold by electrospinning method. The synthesized scaffolds were evaluated for morphology, functional groups, structure, and composition by Fourier-transform infrared spectroscopy (FTIR) , Scanning Electron Microscopy (SEM), and X-ray Powder Diffraction (XRD) analyses, respectively. After characterizing the fabricated scaffold, the viability of L929 fibroblast stem cells was obtained. 

SEM results showed successful integration of polycaprolactone scaffold with chitosan and carbon-iron quantum dot-iron. The average size of polycaprolactone/Chitosan/Carbon-quantum dot-iron nanocomposite was in the range of 32.6-135.0 nm. FTIR results showed the formation of bonds between carbonate and iron nanoparticles. A vibrating magnetometer (VSM) proved superparamagnetic of carbon-quantum dot-iron magnetic nanoparticles. At a concentration of 2% carbon-quantum dot-iron, the scaffold had good biocompatibility, which was proved by a cytotoxicity test.

The results showed that Polycaprolactone /Chitosan /Carbon-quantum dot-iron (PCL/Cs/ CQD-Fe) nanocomposite improves the wound healing process due to its non-toxicity. The biocompatible PCL/Cs/ CQD-Fe nanocomposite is a scaffold of interest in wound dressing that greatly accelerates the skin regeneration process.

Bacteriophages are viruses that specifically target bacteria. Due to their wide abundance in nature and easy isolation from different environments, as well as concern about antibiotic resistance, recently there has been a great interest in using bacteriophages in the treatment of bacterial infections. Also, many studies have been conducted on the application and use of bacteriophages in various industries, including the food industry. However, before using phages, it is necessary to prove that they are safe and harmless, and if necessary, determine the legal requirements for their use. While to date studies of phage therapy have generally been shown to be safe, still, there isn’t a comprehensive understanding of the interactions between phage and the human host.

This study was done to investigate the effects of gamma irradiation on lethal dose 50% (LD50) of honey bee venom.

Venom samples were irradiated at doses of 0,2,4,6 and 8 kGy . Malondialdehyde level and true protein concentration were determined pre- and post-irradiation. Protein subunits of venom was detected by polyacrylamide gel electrophoresis. Allergen compounds were measured using HPLC technique. Lethal dose 50% (LD50) was determined using in vivo trial. Eighty hamsters were allocated to 5 treatments and 4 replicates in a CRD design. Venom solution at dose of 0.5, 0.75, 1 and 2 mg/Kg BW were injected intra peritoneal and mortality recorded then LD50 was computed by Spearman–Karber method. In the final of study, hamsters liver samples collected and fixed in 10% formalin. Liver samples were sliced, fixed and stained by hematoxylin and eosin. Data were analyzed by SAS Software.

The results showed that true protein content and malondialdehyde level in irradiated samples had no differ with the control group (P>0.05). Electrophoresis patterns and HPLC results showed that irradiation at doses of 4 and 6 kGy decreased phospholipase amount and increase the low subunits of protein (P<0.05). Irradiation at doses of 6 and 8 kGy increased LD50 by 34%. Based on the histology results, irradiation of honey bee venom at dose of 4 and 6 kGy could decrease the inflammation of hepatocytes and vein hyperemia in liver.

Irradiation at dose of 6 kGy by removing allergens can be used to reduce the toxicity of bee venom.

The aim of this study was to investigate the effect of application of selenium nanoparticles on anatomy and pattern of tissue differentiation in lemon balm. Plants were treated with nano-selenium (nSe; 0, 10 and 50 mg/l) and bulk selenium (BSe). The results of this study indicated that nanoselenium had a positive and beneficial effect at a concentration of 10, but a concentration of 50 induced toxicity. The microscopic assessment of stem cross sections showed that the diameter of the central cylinder was increased compared to the control. The highest increase was related to the seedlings exposed to the 50 and 10 mg/l. Stem thickness and diameter in the nSe-treated seedlings at 50 mg/l and bulk 10 mg/l were increased compared to the control. Xylem diameter decreased in response to the supplements, the lowest belongs to the nSe50. Monitoring the leaf cross sections showed that nSe10 increased thickness of xylem diameter, palisade and sponge parenchyma compared to the control. Comparison of petiole cross-sections indicated that the thickness of the epidermis and the diameter of the central the central and lateral xylem were changed. While, 50 mg/l nSe declined these traits. Therefore, the results of this study indicate that the application of applied concentration-dependent selenium, in addition to inducing physiological and molecular changes, causes anatomical changes and tissue differentiation. Further research is needed in the future to determine the mechanism of these responses.

Experiments were carried out with four concentrations of nickel chloride (0, 10, 80 and 220 mg/l) and a constant concentration of nano-adsorbent Fe3O4 (4 g/l), plus control. The treatments were soluble in plants as alternatives to normal water. The results were statistically analyzed by analysis of variance. The results showed that the least growth by weight was observed for plants with 220 mg Ni treatment. Proline in shoot increased significantly relative to root compared to control. Measurement of nickel heavy metal content by ICP-AES atomic absorption spectrophotometer showed that the concentration of nickel metal increased in the plant as it increase in the water. Inductively coupled plasma atomic emission spectroscopy is a method of emission spectroscopy that excites atoms and ions with a plasma, causing it to emit electromagnetic radiation at wavelengths characteristic of a particular element. Magnetic nanoparticles treatment Fe3O4 showed a significant reduction in nickel concentrations in the plant, indicating that they were successful in removing nickel metal. The results of antioxidant potential showed that concentrations of nickel as heavy metal stress increased the antioxidant and the treatment of nickel with nanoparticles in all three concentrations reduced the antioxidant. The nickel heavy metal in high concentrations is toxic for sunflower plant and the magnetic nanoparticle successfully absorbs the nickel metal up to 99 percent and reduces its toxic effects in the water.

Nowadays, the nanotechnology development has expanded to various medical fields, drug delivery, etc. novel drug delivery systems have made diseases cure such as cancer easier. Alumina nanoparticles have a vast use in this area due to their thermal properties. Among numerous applications uses of these nanoparticles, one of the hazards to discuss is their toxicity. Besides, surface modification of these nanoparticles with chitosan as a biopolymer lead to the bioavailability improvement. In this research, alumina NPs were covered with chitosan biopolymer. Analysis of the size of particles indicated about 70 nm. FT-IR analysis on alumina and alumina/chitosan NPs showed surface modification of alumina NPs greatly. Besides, TEM images of the nanoparticles approved suitable size for drug delivery purposes. HeLa cells were treated with Alumina and Alumina/CS for 24 h, and IC50 concentration was determined. Toxic effects of these components on the cells were evaluated by MTT assay and acridine orange/ethidium bromide (AO/EB) staining. The results of the bioassay of nanoparticles well showed their successful coating by chitosan polymer. Moreover, the results detected that Alumina samples had toxic effects on the cells in a dose dependent manner and their IC50 concentration was about 25 mM. While coated samples had significantly lower toxicity and it had no significant toxicity on HeLa cells in concentrations below 5 mM.

Microplastics have become one of the major and emerging environmental challenges due to their ubiquity in the oceans and their ability to carry toxic chemicals. In recent decades, with increasing production and global demand for plastics, the entry of these materials into marine environments has increased dramatically. Therefore, due to the importance of the oceans and seas in terms of food supply and climate issues, the environmental consequences of such wastes have been considered more than ever. The distant transport, persistence and universal dynamic forces of plastic remains are key aspects to considerate the fate of this material and any potential impacts of plastic remains on marine ecosystems. A plastic remains accumulates chemical contaminants; it is accepted to the world how plastic remains are considered toxic. Because of their potential to bioaccumulation, ingestion of micro plastics can enter human food chains via several pathways. Strategy for control of micro plastics pollution should mostly focus on source reduction and afterward on the development of cost-effective clean up and remediation technologies.

The Discreaption Research Method has been implemented based on library resources, databases, and scientific reports. The hypothesis of this research is the existence of harmful effects of microplastics and its report by researchers.

Microplastics have become one of the major environmental challenges due to their ubiquity in the oceans and their ability to carry toxic chemicals. These pollutants pose a serious threat to the human food chain due to factors such as bioaccumulation and biomagnification. However, developing new methods to reduce the identified risks of bioplastics and microplastics is significant. Also, it should be assessed how intermediate plastic waste creates these key aspects for environmental chemical pollutants.

The term microplastic has only been widely used in the last two decades, although there are still many questions about the extent of their destructive effects. Therefore, due to the limitations of existing studies, further research on sample processing and analysis techniques to control and reduce the entry of microplastics into the water and food chain is needed until standardization and coordination for sampling and recognition of samples are carried out.

In order to predict the environmental effect of biosynthesized magnetic iron oxide nanoparticles (magnetite or bio-Fe3O4) using marine green algae Ulva flexuosa in aquatic ecosystems, its toxicity was assessed on the early life stages and larvae of zebrafish, Danio rerio as an aquatic model. For this purpose, 10 fertilized eggs of zebrafish were exposed to serial concentrations of bio-Fe3O4 nanoparticles (0, 10, 50, 100, 200 and 500 mg/L) in 6 well plates in 6 replicates. After 12, 48, 72, 96, 110 and 134h samples were assessed. Results showed that the percentage of hatching rate and the larval survival rate decreased with increasing exposure time and concentration of magnetite nanoparticles (P<0.05). After 48h of exposure, in the highest concentration (500mg/L), the hatching rate of fish decreased to 36.6% (48 h LC50 = 638.2 mg/L) and after 134h of experimental periods, the survival rate of larvae reached to 43.3% (134 h LC50 = 645.4mg/L). The mean of all skeletal malformations in zebrafish would be significant with an increase in a dose- and time-dependent pattern during the exposure to nanoparticles and in the highest dose (500mg/L) reached 13.3% (P<0.05). It seems that the toxicity of bio-Fe3O4 nanoparticles affected by their particle size (13.8nm) and potentially toxic kinetic actions of particles at the nanoscale.

Glyphosate based pesticides are safe for humans, but their widespread use in agricultural areas and water contamination raised serious concerns about its toxicity. The aim of this study was to investigate the effects of different doses of roundup on body weight, gonadosomatic index (GSI) and histological alterations of gill and testis in common carp. 32 common carp broodstock (1723.75 ± 72.72gr) were randomly divided into 4 groups of 8 fish. . One group (control) had no exposure to herbicide and 3 groups (treatment) were exposed to rounduppesticide at 4 concentrations (5, 10 and 15 mg/L) for 10 days. After treatment period, body length, body weight and GSI index were determined and gill and testis samples were prepared for histological studies. Based on the results, exposure to roundup at a dose of 20 mg/L caused a significant decrease in body weight on the10th day and GSI index on the 5th and 10th day (p<0.05). In fishes exposed to roundup (20mg/L) necrosis and disintegration of gill lamellae structure, adhesions of gill lamellae, separation of basement membrane and damage of gill epithelium and exudation of blood cells were observed. In the testis of fish exposed to the highest dose of roundup, an increase in the number of spermatogonium due to reduced spermatogenesis, degradation of spermatocyte, reduction of spermatozoa, reduction of sperm storage tubules diameter and destruction of interstitial duct and sertoli cells were observed. The results indicated destructive effects of sublethal doses of roundup on gill structure and reproductive performance of common carp.

In this study, bioassay test of Shiraz municipal rubbish compost on germination and seedling growth of wheat, barley and rapeseed with concentrations of 0 to 20% of the compost extract with three replications was investigated. In addition, a comparison between two methods of compost toxicity evaluation was occurred. Petri dishes were harvested after7 days and then the radicle and plumule length were measured. In all three seeds, the highest germination percentage and radicle and plumule length was in control and the lowest in 20% of compost extract. The compost extract, causes toxicity and limitation in germination and growth of seedlings, if prepared from raw materials containing toxic organic compounds and heavy metals and not completely processed. It is recommended that agricultural waste can be used in the preparation of compost and urban wastage can be consumed as little as possible. Comparison of the two methods showed that this article method, due to lower concentration of the extract, the seed germination percentage was significantly higher and, due to similarity to the natural condition and absorption of some extract by soil matrix, it is more appropriate for evaluation of compost toxicity.

The synthesis of metal nanoparticles has attracted the attention of scientists in various fields, particularly in the chemical, physical, biological and medical sciences. Using extract of plant for nanoparticle synthesis can be advantageous over other biological processes because it eliminates the elaborate process of maintaining cell cultures and can also be suitably scaled up for large-scale nanoparticle synthesis. In this study, zinc oxide (ZnO) nanoparticles were successfully synthesized from ZnNO3 using Olive (Olea europaea).  Nanoparticles were characterized with the help of Transmission electron microscopy (TEM) and UV–Visibe absorption spectroscopy. To study the effects of zinc oxide (ZnO) nanoparticles (0, 200, 400 ppm) on growth, proline and Malondialdehyde (MDA), total phenol, flavonoid, Hydrogen peroxide (H2O2), chlorophylls and anthocyanin content in plant of Borago officinalis, experiment was carried out at shahid bahonar university of Kerman University in 2014. Synthesised ZnO nanoparticles were confirmed by the absorption maxima at the wavelength of 370 nm. TEM image revealed that ZnO nanoparticles were spherical with average size 41 nm. Results showed the plants that treated with zinc oxide (ZnO) nanoparticles, increased root and shoot length. But soluble suger, anthocyanin and CAT activity in the plants that treated with zinc oxide (ZnO) nanoparticles had no significant effect. On the other hand, Zinc oxide (ZnO) nanoparticles decreased proline and chlorophyll content. In addition, ZnO nanoparticles treatment at 400 ppm increased phenol content, H2O2, lipid peroxidation and APX, GPX, PAL activity. Reactive oxygen species generation was a toxicological mechanisms of nanoparticles that increased H2O2 content and lipid peroxidation in plants. ZnO nanoparticles causing increased production of reactive oxygen species and decreased proline and chlorophyll content in Borago officinalis.