نشریه یافته های نوین در علوم زیستی
سال ششم شماره 1 (پیاپی 19، بهار 1398)

Impaired motor functions were reported in cholestatic animals. This disorder in the function and death of motor neurons is highly dependent on changes in the environment around astrocytes and the blood-brain barrier, which is moderated by the aquaporin 4 protein. For this reason, the effects of cholestasis on motor cortex histology and morphology and aquaporin 4 protein levels were investigated in this study. Samples were stained by hematoxylin-eosin method. Histological changes in cortical brain were investigated. The amount of AQP4 protein in control, sham, and experimental groups were tested by immunohistochemistry. The thickness of motor cortex in cholestatic samples increased in comparison with the control and sham groups. Also, cholestasis caused wrinkle chromatic nuclei. On the other hand, tissue necrosis was detected in cholestatic group compared with sham and control groups. Reduction of cells densities in some cortical layers has been observed, which is probably indicative of cholestasis-induced cell death. AQP4 expression significantly decreased in BDL (p <0.05), but not in other groups (P<0.05). In this study, the pathology of motor cortex, which has also been associated with the decrease of neurons, could be considered the cause of motion abnormalities and AQP4 level reduction in cholestatic rats.

In this study, the cytotoxic effects of aqueous and ethanolic extracts of Sedum album L. on human stomach cancer cell line (AGS) and breast cancer cell line (MCF-7) were evaluated by MTT, BrdU and TUNEL assays. The results demonstrated that both extracts had antiproliferative and apoptotic effects in a dose-dependent manner. The MTT assay data revealed that the AGS cell underwent more cytotoxicity in comparison with the MCF-7 cell. It also revealed that ethanolic extract was more potent than aqueous extract. The BrdU assay results showed that the proliferation of AGS and MCF-7 cells was reduced to 50% and 43%, respectively, at the highest concentration of the aqueous extract. In addition, the ethanolic extract reduced the proliferation of AGS and MCF-7 cells to 75% and 60%, respectively. The AGS and MCF-7 cells underwent 52% and 12% apoptotic death upon treatment by the ethanolic extract as TUNEL assay showed. The aqueous extract induced 28% and 25% apoptosis in the AGS and MCF-7 cells, respectively. Both inhibition of proliferation and induction of apoptosis are desirable strategies for cancer treatment among researchers. Identification of S. album compounds and analyzing their effects in animal model of cancer can help us with understanding its anti-cancer properties.

Impranil DLN is a class of plastics belonging to the polyurethane family with high application in textile industries. The aim of this study was to evaluate the potential of native strain to degrade impranil DLN. In this study, yeast strains were isolated from different areas and purified in minimal medium containing 1% impranil. Isolate NS-10 was selected as the superior strain capable of degrading impranil and identified through PCR and ITS gene. Esterase, urease and protease assays were carried out for the superior strain. Finally, the biodegradation of impranil was investigated. In total, 40 yeast strains were isolated and isolate NS-10 was selected as a superior strain based on impranil removal assay. NS-10 strain was identified as Sarocladium kiliense with 100% homology. Enzymatic assays showed that the S.kiliense could produce esterase, urease and protease. In addition, it could produce significant clear zones on impranil plates. Degradation rate for impranil was 100% for 10 g/l within 14 days. Finally, S.kiliense was taken to medium containing pure polyurethane film and the capacity of degradation was investigated by the scanning electron microscopy. Our results indicated that S.kiliense is capable of degrading impranil. These results could contribute to a better insight into the mechanism of plastic biodegradation.

New properties of nano-materials have made nanotechnology the leading part of biology and medical sciences. Due to their various biomedical properties, iron-based magnetic nanoparticles (MNPs) have been highly considered by biological researchers. Nowadays, increasing resistance to antibiotics is a major problem in treating clinical infections. Finding new antibacterial agents is therefore essential for the treatment of resistant strains. In this study, the iron oxide MNPs were produced using culture-medium supernatant of a newly isolated bacterium to investigate the inhibitory effects of the NPs on strains with a major role in clinical infections. Biosynthesis of iron oxide MNPs were detected by UV-Vis spectroscopy and the average size of particles was estimated by dynamic light scattering technique. The anti-bacterial activity of these NPs against E. coli and S. aureus was investigated using methods for the calculation of bacterial sensitivity coefficient. In the presence of NPs, the highest sensitivity coefficient value was observed for E. coli in 1xMIC concentration. On the other hand, S. aureus showed the lowest value. The death rate of the two strains in contact with NPs followed the first order kinetic equation and the survival rate decreased with the increase of exposure time. The results of this study as well as the high functionality of iron oxide MNPs, make its application desirable in the prevention and treatment of clinical infections.

Cutin is a polymer that is constructed in plants by the condensation and oxidation of fatty acids and plays a key role in the protection of plants against pathogens. Cutinase is a hydrolase enzyme that breaks down the cutin. The purpose of this study was to extract cutin from red apples with oxalate buffer, cutinase enzyme activity assay in LB culture, and bioinformatic analysis. To attain these purposes the cutinase-producing strains that had previously been isolated were inoculated in culture medium containing cutin. After initial culture, the bacteria were cultured in LB medium and cutinase activity was measured using the p-Nitrophenyl butyrate. In order to execute bioinformatic analysis, the isolated sequences of six cutinase-producing bacteria were analyzed based on computational data bases and their phylogenetic trees were prepared. Then, the similarities in the sequences of a large number of cutinase-producing samples were analyzed by drawing the phylogenetic tree. The results showed the separation of cutinase-producing prokaryotes from cutinase-producing eukaryotes. Then, the sequence of 16S rDNA of these cutinase-producing samples as well as the samples we had prepared were evaluated and their phylogenetic relationships were determined. This analysis showed that the new sequence stood alongside the bacterial samples. Thus, our cutinases may be similar with these bacterial cutinases in structure and function.

In Acidithiobacillus ferrooxidans, the proteins present in the electron transfer pathway cause ferrous iron oxidation which leads to uranium extraction. The relationship between gene sequence and uranium extraction has not been investigated yet. Based on the changes in uranium extraction, the changes of rus gene sequence can reveal the direct and accurate role of this protein. For this purpose, a random mutation was induced in native Acidithiobacillus sp. FJ2 by two doses of 0.8% and 1% of DES. Then, the bacteria was transferred into a medium which contained 50% uranium ore to carry out the bioleaching process. After measuring the amount of the extracted uranium, iron, Eh and pH, genomic DNA was extracted to investigate the rusticyanin gene (rus) sequence sent for sequencing after performing PCR. Then, the wild-type gene sequence was compared with the mutant by Bioedit v7.2.5 software. The results showed that uranium extraction increased by mutant bacteria with DES 1% between 7-11 days in comparison with wild bacteria. However, there has been no change in the functional areas of the rusticyanin gene. It seems that DES affected other effective genes in the electron transport chain or regulatory areas, which required further studies.

The production of pigments from bacteria is significant due to the low cost, high yield and ease of extract compared with other sources. Carotenoids are one of the most important pigments with antioxidant properties which are the precursor of vitamin A synthesis and have antibody overproduction ability, anti-tumor activity and inhibitory effect on the cardiovascular disease. The present study aimed to isolate and identify carotenoid-producing bacteria by high-performance liquid chromatography (HPLC) analysis of their carotenoid pigments. Twenty soil samples were collected from different regions of Tehran. After serial dilution each sample was cultured on BHI agar medium and incubated at 37°C. The pigment-producing bacteria were selected for further identification and their pigments were extracted by methanol. The screening was carried out at two levels: i) selection of the strains by visual color inspection, ii) analysis of the pigment extracts by UV-VIS spectroscopy and HPLC. The isolates were identified by phenotypic methods and their 16S rDNA gene was amplified by PCR method and sequenced. Staphylococcus epidermidis, Micrococcus aloeverae, Citricoccus alkalitolerans, Rhodococcus zopfii, Arthrobacter agilis, Dietzia natronolimnaea and Rhodococcus ruber were identified as carotenoid-producing strains. The highest rate of absorption was observed using UV-VIS analysis in Staphylococcus epidermidis and Dietzia natronolimnaea. The comparison of HPLC analysis with the standard β-carotene curve showed that the carotenoids were beta-carotene. Micro-organisms are a potential source in the production of pigments. In this study we introduced two genera of bacteria (Staphylococcus epidermidis and Dietzia natronolimnaea) with carotenoid-producing ability.

Bacterial communities are able to form complex and three-dimensional biofilm structures. Biofilm formation is an ancient and integral component of the prokaryotic life cycle and a key factor for survival in diverse niches. In biofilms, bacterial lifestyle changes from free-floating cells to sessile cells. Presence in biofilms gives new traits to bacteria, which distinguish them from free cells. The presence of bacteria in biofilms results in high resistance to antimicrobial treatments and oxygen deficiency. Biofilms are formed in response to different environmental signals and many genes are involved in their production. Biofilms can be problematic in fluid transfer pipelines, on medical devices, as well as implants in the patients’ bodies. However, they can be applied for useful purposes such as treating industrial and agricultural wastewater, bioremediation of heavy metals and in air pollution biofilter systems. The potential of forming biofilms in pathogenic bacteria is an advantage for their survival in unfavorable conditions, and cause a lot of problems in their removal as the bacteria show more resistant to antibiotics and chemical pesticides in biofilms compared with free living cells. The ability to form biofilms in plant-beneficial rhizobacteria used for plant disease biocontrol, plant growth promotion and the improvement of agricultural products quality is an important advantage especially in their mass production and commercializing process. Considering the importance of bacterial biofilms in human life, this paper evaluated the importance of biofilms from different aspects.

It is necessary to reduce the amount of sulfur in fossil fuels due to direct impact of the quality of these fuels on the environment. In this research, a novel fungus strain of Exophiala spinifera, namely FM, was used to desulfurize dibenzothiophene (DBT) as a model cyclic sulfur compounds in oil and fossil fuels. HPLC analysis indicated that the fungus was capable of reducing 99% of DBT concentration in BSM medium after seven days. This fungus utilized DBT as a sulfur source by co-metabolism reaction with other carbon sources such as glucose. Exophiala spinifera was inoculated in BSM medium containing DBT with various carbon sources including ethanol, glucose, succinate, and glycerol. This fungus had the highest growth and desulfurization capability on glucose as a carbon source after 96 h. E. spinifera had best growth and desulfurization rates in 0.3mM DBT. Optimum DBT desulfurization and growth rate of this fungus was observed at 26-30 oC. Suitable pH for the optimum growth and desulfurization activity of E. spinifera strain FM ranged 4-5.

Through a survey of macrofungi in Ghalajeh heights and its surrounding plains, conducted from 2014- 2017, twelve specimens of macroascomycota were collected. The specimens were identified on the basis of macro- and micro-morphological characteristics. The internal transcribed spacer sequences of the selected specimens were analyzed to confirm the morphological identification. Based on the results, five species, including Terfezia claveryi, Tirmania pinoyi, Helvella acetabulum, Picoa juniperi and Picoa lefebvrei were identified. T. claveryi and T.pinoyi species had been previously reported from Kermanshah Province, but H. acetabulum, P. juniperi and P. lefebvrei species were reported for the first time.

The identification of the characteristics of native halophytic species is very important for their practical application. The present study was carried out to identify the halophytic species of a desert and highly saline region around the city of Khosf, southern Khorasan Province, and to detect their general tolerance mechanisms (i.e. salt exclusion or inclusion). Sodium accumulation in the roots and shoots of seven species, including Launaea arborescens, Peganum harmala, Pteropyrum olivieri, Artemisia santolina, Zygophyllum eurypterum Boiss, Aerva javanica, Pulicaria gnaphalode, and their rhizosphere soil were determined. The bioconcentration of sodium from soil to roots (BCF), its translocation from roots to shoots (TF), and its accumulation in the shoots (AF) were then calculated. Results showed that the soil of the studied area was clay loam with a high EC of 65 ds/m, indicating its high salinity level. According to the values of sodium adsorption ratio (SAR) and the exchangeable sodium percentage (ESP) and regarding EC, the soil of studied region can be regarded as a saline-sodic soil. The value of TF in some species was higher than 1. However, none of the species had BCF and AF greater than 1, thus, none of them could be considered to be salt accumulator. Instead, it could be assumed that all of the studied species were salt, or at least, sodium excluders.

In order to study the effects of magnetopriming on the physiological and phytochemical characteristics of Hyssopus officinalis plants, this research was conducted as a factorial experiment in a completely randomized design. Results showed that magnetopriming (particularly at 200mT/5 min) increased the level of shoot dry weight (82.6 percent), root dry weight (86.5 percent), total chlorophyll (32.8 percent), carotenoids concentration (32.4 percent) and polyphenols content (2 folds) in 60-day-old Hyssopus officinalis. Also, electrolyte leakage and lipid peroxidation decreased by 27.6 and 45 percent, respectively. In addition, reducing power, DPPH and superoxide anion scavenging activities significantly augmented. However, higher activities of superoxide dismutase (76 percent), catalase (4.2 folds), ascorbate peroxidase (2.4 folds) and guaiacol peroxidase (48 percent) were found at 90 mT. Results suggested that the application of magnetopriming promoted growth in H. officinalis through augmentation of cellular membrane integrity as well as biomass and photosynthetic pigments content. Furthermore, it was found to enhance the antioxidative system. Magnetopriming might apparently improve the medicinal properties via increasing the level of polyphenols and antioxidant capacity in H. officinalis.

The availability of iron for roots has been demonstrated as a critical factor in plant production. The addition of synthetic iron chelates to soil is a common practice in agriculture, which is not economically beneficial. Besides, chemical iron fertilizers cause many problems such as food contamination and environmental pollution. Development of natural Ferrioxamine B as an efficient and safe iron source may be the best strategy to overcome plant iron deficiency and prevention of synthetic agent pollution. The present study investigates the ability of a hydroxamate type siderophores (Ferrioxamine B) as a substitute Fe source during tissue culture of chickpea plants. For this purpose, embryo axes from chickpea seeds were surface sterilized and cultured in 1/2MS and MS culture media including 3% sucrose and 0.8% agar with Ferrioxamine B or Fe–EDTA. The root and shoot length, shoot and root dry weight, total fresh and dry weight, as well as chlorophylls a and b were analysed. Results indicated that Ferrioxamine B did not increase chlorophylls a and b in comparison with Fe-EDTA. However, rooting (22%), total dry weight (38%) and root (75%) and shoot (22%) dry weight significantly (p≤0.05) increased in MS containing Ferrioxamine B in comparison with Fe-EDTA. Consequently, Ferrioxamine B is introduced as a cost-effective and applicable Fe source to favour iron deficiency in vitro.

The environmental conditions which the parent plant has undergone during seed development can affect many properties of the seeds such as degree of dormancy, weight and the amount of their compounds. In this study, mature pistachio seeds of Ahmadaghaei cultivar, collected from the two cities of Rafsanjan and Shahrbabak located in Kerman Province (Iran), were compared. It was found that the seeds collected from Shahrbabak being a cooler and wetter region had a longer dormancy, although the water content of the two seed series were similar. Dehydrin proteins generally play a role in protecting plant cells against dehydration stress. Dehydrin contents of the cotyledons and embryonic axes of the two seed series were compared by western blot method using an antibody against the conserved K segment in dehydrin proteins. It was found that the cotyledons had five dehydrin versions with molecular weights of 23, 25, 32, 39 and 48 kDa, the expression of which not being influenced by environmental factors. It was found that the embryonic axes had seven other versions of dehydrin with weights of 17, 19, 20, 28, 67, 77 and 98 kDa in addition to those five versions. This shows higher protection of embryonic axes compared with the cotyledons. The 25 and 28 kDa versions had higher expression levels in embryonic axes of Shahrbabak seeds, while the 39 kDa version had a higher expression level in embryonic axes of Rafsanjan seeds.