جستجوی مقالات مرتبط با کلیدواژه « سمیت » در نشریات گروه « زیست شناسی »

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.

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.

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.

Due to very small dimensions, nanomaterials can have different properties compared to their bulk form. In nanometer dimension of material, atomic behavior dominates. Such behavior changes may adversely affect biological organism, especially phytoplankton as the basis of food chain cycle. For this reason, in current research, toxicity of CuO nanoparticles (CuO NP) on Scenedesmus dimorphus has been evaluated. The average size of CuO NP used were 20 nm. 

The experiments were conducted under OECD201 method. The toxic effect of CuO NP was investigated at 5 different concentrations of 2.5, 6.5, 17.4, 45.7, 120 mg/L against control in three replicates for each treatment and control. All samples were treated at constant temperature of 24 °C and 12-hour period of light and dark for 72 hours. Algae count was done at time intervals of 24, 48 and 72h. Chlorophyll assay was done according to ASTM standard. 

EC10, EC50, and EC90 amounts for 72 hours were 0.18, 28.84 and 4477.35 mg/L, respectively. With time, chlorophyll concentration was decreased in all treatments except for 57.68 mg/L. Carotenoid showed significant decrease between all treatments and the control and also among different treatments (p<0.05) and in 72h three treatments had different carotenoids (p<0.05).Discussion and

These results showed that CuO NP had significant toxic effect on Scenedesmus dimorphus and resulted to reduction in growth rate and increase in doubling time. Also, the percent inhibition was increased with increasing CuO NP concentration. The chlorophyll and carotenoid levels decreased in Scenedesmus dimorphus by increasing CuO NP concentration.

In this study, the toxicity effect of silver nanoparticles on colon cancer (HT29) was measured and evaluate the expression of the matrix metalloproteinase 9 (MMP9) genes. In this study, the synthesized AgNPs were characterized by the transmission electron microscopy (TEM) analysis. The cytotoxicity effect of silver nanoparticles against the HT29 cell lines was investigated using MTT assay. Also, MMP9 gene expression was measured using real time PCR technique. The TEM result showed that the fabricated AgNPs were mostly spherical in shape and having an average diameter of 22 nm. The results revealed that AgNPs significantly decreased the viability of cells in dose-and time dependent manner (P<0.001). Also, there was a significant relationship between the differences in concentrations. MMP9 gene expression levels in HT29 cells were decreased to 0.4897 ± 0.00679 (P<0.001) compared with the control group. According to the results, the green fabricated AgNPs can be considered as a promising strategy for the treatment of colon cancer.

In nanoecotoxicology science, fish erythrocyte micronucleus assay for the monitoring genotoxic potential of nanoparticles is a powerful biomarker. This study was conducted with the aim of investigating genotoxicity of magnetic iron oxide (Fe3O4) nanoparticles in red blood cells of common carp (Cyprinus carpio) using micronucleus assay under acute and chronic treatment. In the current experimental study, the genotoxit toxicology of Fe3O4 nanoparticles was performed during an acute (96 hours; 5 concentrations including 0, 10, 100, 500, and 1000 mg/l) and chronic (14 days; 3 concentrations including 0, 100, and 500 mg/l) of Fe3O4 nanoparticles in three replications. The data were analyzed by IBM SPSS 19, using two-way ANOVA, and Duncan's new multiple range test. Findings: Acute exposure to Fe3O4 nanoparticles had no acute toxicity effect juvenile carp (C. carpio). By increasing the concentration of nanoparticles in a 96-hour interval, the frequency of micronucleus (‰) and other abnormal forms around the red blood cell nucleus of juvenile carps showed a significant increase compared to the control group (p<0.05). In the chronic treatment at concentrations of 100 and 500 mg/l of Fe3O4 nanoparticles, the rate of increase in the frequency of micronucleus was similar to the acute functional test of concentration. Although Fe3O4 nanoparticles do not have acute toxicity effects in common carp and are non-toxic, they tend to induce genotoxic effects by increasing the frequency of micronucleus and other abnormalities of the red blood cell core during a concentration-dependent process. So, it seems that the release of FeO4NPs into the environment, it is probable adverse effects on aquatic ecosystems.

Based on the various applicants of iron oxide nanoparticles (magnetite, Fe3O4-NPs) and their final entrance to aquatic ecosystems, the present study was conducted to investigate impacts of acute exposure (96 hours) of chemogenic Fe3O4-NPs (concentrations of 10, 100, 500, 1000, 2000 mg/L) and Bio-Fe3O4-NPs (500.1000 mg/L) were biosynthesized by algae Ulva prolifera to changes in hematological indices including total and differential count of white blood cells (WBC), red blood cell (RBC) count, hemoglobin, hematocrit, RBC indices including MCV, MCH and MCHC, biochemical parameters including glucose and alkaline phosphatase (ALP), and immune responses including nitroblutterazolium (NBT) test in common carp (Cyprinus carpio) (average weight of 10.04±1.83g) compared to the control group (without NPs). The results showed that, despite the no acute toxicity of both types of magnetite nanoparticles in common carp, with increasing concentrations of Fe3O4-NPs and Bio-Fe3O4-NPs, a significant increase in hematocrit, hemoglobin, RBC, WBC (chemical type), glucose, and ALP, and a significant decrease in MCV and MCH were observed, while RBC was introduced as the most effective marker (rc = 0.952, rb = 0.982, P<0.00001). However, at the same concentrations, the intensity of the changes in the indices in the exposed group to Bio-Fe3O4-NPs was lower than Fe3O4-NPs, which is probably due to differences in nature, synthesizing method and biocompatibility potential of Bio-Fe3O4-NPs.