نشریه زیست شناسی کاربردی
سال سی و سوم شماره 2 (تابستان 1399)

In the current study, the effect of antibiotic on bacterial contamination and browning in in vitro condition and effect of different concentration of sucrose and activated charcoal in organogenesis and browning date palm explants were investigated.In first experiment, apex meristems of date palm (Phoenix dactylifera) cv. Estamaran were cultured in media containing two types of antibiotics (cefotaxime and chloramphenicol) at 3 different concentrations (0, 50, or 100 mg L−1). In the second experiment effect of different concentration of sucrose (30, 40 and 50 g L-1) and 2 concentration of activated charcoal (0.5 and 2 g L-1) on organogenesis and explant browning were studied. Result showed that minimum bacterial contamination accrued in 100 mg L-1 chloramphenicol in the medium. The maximum browning occurred in medium contain 100 mg L-1 cefotaxime and 100 mg L-1 chloramphenicol. In second experiment shoot regeneration was enhanced when sucrose concentration was used at 30 or 40 g l−1, but 50 g L-1 of sucrose reduce that. Also the use of 0.5 g L-1 and 2 g L-1 activated charcoal was not significantly different to reduce the browning of explants. This result developed an initial protocol for micropropagation of date palm. The type and concentration of antibiotic and sucrose concentration were found to have significant effect on organogenesis and browning of explants. Treatment with higher levels of antibiotic (especially cefotaxime) increased browning. This successful protocol would facilitate the vegetative propagation, conservation, and genetic engineering of this species.

The wide use of stem cells for therapeutic applications requires frequent production of a large number of cells with proper characteristics under controlled conditions in bioreactors. In this study, U937 cells were introduced as a model of floating stem cells inside alginate-gelatin microcapsules with a cell density of 2.5 × 106 cells/ml. The results showed very good growth of microcapsules inside the flask. Microcapsules were cultured in two different bioreactors with different concentrations of oxygen in two perfusion bioreactors with external stirrer loop (PC-ESCT) and bubble column (B.C). The results showed an increase of 9.2 ± 0.9 in the perfusion reactor with the external stirrer, while due to the high stress they were unable to grow properly in the bubble column reactor. The results confirm the suitability of alginate-gelatin microcapsules for the propagation of stem cells in dynamic systems. The perfusion bioreactor with external loop loops, by reducing the shear stress and better oxygen distribution, creates a homogenous and more suitable environment for growth and proliferation of cells.

Lichens produce high diversity of metabolites and they have different biological activities including antibacterial, antifungal, antiviral, anti-inflammatory and the cytotoxic effects. In this study, the impact of antimicrobial substances of lichens were studied. For this purpose, the lichens of northern forests around Babol city was collected and via the morphological and microscopic characteristics, biochemical and molecular methods were identified. Then, ethanol extracts of lichens were prepared. Antimicrobial effects of extracts was assayed using the diffusion agar method and the determination of minimum inhibitory concentration against five bacteria, Bacillus cereus, Xanthomonas campestris, Escherichia coli, Staphylococus aureus and Pseudomonas aeruginosa. The studies showed that the extract of Leptogium saturninum, Ramalina peruviana, Punctelia borreri were effective against X. campestris، S. aureus. However, in the case of Bacillus cereus and E.coli only the extract of R. peruviana was effective. Furthermore, measuring the diameter of zone inhibition and MIC against three clinical Candida albicans, Candida tropicalis, and Candida glabrat showed that the extracts of Leptogium saturninum, Ramalina peruviana were effective on all the strains. However the extract of Punktelia subrodecta was effective only on C.albicans. The substance of lichens, which assayed by biochemical tests showed that due to the presence of phenolic compounds, lichens show high antimicrobial properties. It should be carried out the antimicrobial experiments on a wide range of environmental and pathogenic microorganisms.

Gypsophila mucronifolia Rech. is an endemic plant species of Caryophyllaceae that It has been reported from gypsum deserts around Semnan, Iran. A few reports have been made on the distribution of G. mucronifolia in relation to its descriptive compromise characteristics with soil and altitude factors. Ecological studies of G.mucronifolia were performed for the first time. This species grows at altitudes of 1500 to 1800 meters from sea level, often on the northern slopes. Using Canoco for windows 4.5 software and statistical analyzes of RDA, the effect of environmental factors on the distribution of G.mucronifolia was determined. Elevation and gypsum contents showed positive correlation and content of CaCO3 and Na negative correlation with occurrence and growth of G. mucronifolia. The leaf surface with a scanning electron microscope (SEM) has studied that show glandular hairs on stem and leaves it there, but did not observe on the calyx. Leaf cells of G. mucronifolia are filled with druse crystals.

Silicon nanoparticles have distinctive physicochemical characteristics. They are able to enter into plants and impact the metabolisms of plants as well as improve plant growth and yield under unfavorable environmental conditions. This research was done in order to study the physiological effects of nanosilicon on Crocus sativus corm. The corms were treated with silicon nanoparticles in concentrations of 0, 9 and 18 mg L−1. The experiment was done as completely randomized design in three replicates. The results showed that nano-silicon treatment increased content of silicon, potassium, iron, zinc, magnesium and calcium contents in plants but did not affect the fresh and dry weight as well as protein content, significantly. Moreover, the number of daughter corms, malondialdehyde and proline content significantly increased in nano-silicon treated plants as compared to non-treated control. The maximum content of total phenolics and flavonoid content were observed in plants treated with 9 and 18 mgL-1 respectively. Based on the results, it can be concluded that the examined concentrations of silicon nanoparticles can increase saffron corm nutrient content, its capacity of antioxidant system by the production of secondary metabolites.

Studies indicate that oxidative stress has important role in the pathogenesis of Alzheimer disease. Betaine has neuroprotective and antioxidant properties.  The purpose of this study was to investigate the effect of betaine on memory dysfunction induced by intra-hippocampal injection of amyloid beta and measurement of superoxide dismutase (SOD) activity. In this experimental study, animals were divided into 5 groups (n=8 in each group) including: control group, Alzheimer group and betaine (5, 10, and 15 mg/kg body weight + Aß) groups. Seven days after Aß injection memory was assessed by avoidant learning. The activity of antioxidant enzyme was measured via chemical methods. Data were analyzed by One-way ANOVA test.

The results showed in the Alzheimer's group, Aß impaired memory and reduced SOD activity in comparison with control group.  In contrast, betaine pretreatment significantly improved memory and increased SOD activity.This study shows that betaine as an antioxidant can improve memory by decreasing the oxidative stress.

Nano protein structures can be formed by the intrinsic ability of molecular self-assembly or via intermediates which improve their assembly. Hydrophobicity is the most important factor among the other intrinsic self-assembly factors and the other intermediates such as glutaraldehyde may lead to protein-assembly and nanoparticles formation. In this study, Aggrescan 3D software was employed to investigate protein self-assembly properties. Peroxidase enzyme was selected to form protein nanoparticle, and glutaraldehyde changed it to a nano enzyme.FESEM and DLS analysis represented that the average size of nano enzyme is about 500 nanometers. Comparing biochemical properties of peroxidase enzyme before and after changing into nano, showed that the activity of nano enzyme at 20°C, pH7 has decreased as compared to the monomeric enzyme. Based on homology, the PDB structure of two peroxidase enzyme was identified. Then, the connection between glutaraldehyde and two peroxidase enzymes was detected. Enzyme residues with hydrogen binding connections to glutaraldehyde were also detected by using LigPlot software and the residues in active side of enzyme were determined by COACH server. Glutaraldehyde is connected to residues in active siteof the enzyme. Molecular dynamic Simulation was performed in the time duration of 5 nanoseconds and 30°C and it showed that monomer enzyme and nano enzyme are both stable in this time duration and temperature.

Sexual dimorphism of gnathopods 1 and 2 and uropod 3’ shapes in Parhyale darvishi (Momtazi and Maghsoudlou, 2016) were investigated by geometric morphometrics. A total 50 males and 50 females were experimented. Anatomical aspects of gnathopods and uropods were photographed and cartesian coordinate (semilandmarks of organs' margin) aligned by semilandmark sliding based on minimum bending energy. Statistical significance of sexual dimorphism was tested by multivariate analysis of variances; linear discriminant analysis and clustering analysis (ward method). Multivariate regression analysis based on partial warps and uniform components was used to depicting shape variations related to sex [1]in studied anatomical parts in the form of deformation frames. The results show all three anatomical parts was significantly different shape in male and females (F>17.15, p < 0.0001). The deformation regression frameworks of first gnathopod show that the ratio of length to width in females are less than males. The second gnathopod has an oval shape in females instead of circular form in males. The shape of third uropod in males is more extended and bearing subacute angles. Based on present studies, the accurate description of sexual dimorphism specially in taxonomic characters provide ability for identification based on females and detail study of species.

Emission of greenhouse gases and plastic wastes are one of the most important environmental problems in the world. The purpose of this study was to use the bacterium Ralstonia eutropha as the host for recombinant carbonic anhydrase enzyme which is used for carbon sequestration and poly hydroxyl butyrate (PHB) production. The carbonic anhydrase gene (CA) was inserted in the expression vector and transformed into Ralstonia eutropha. Then PHB production was assayed by FT-IR and GC-MS methods in recombinant and non-recombinant bacteria in different concentrations of LB medium in the presence and absence of CO2. Production of PHB in LB medium increased 31.49 percent in recombinant bacteria in the presence of CO2.  These increases were 18.44 and 34.44 percent compared to non-recombinant bacteria in presence and absence of CO2, respectively. In 0.5 LB medium, the recombinant bacterium produced 26.57 percent PHB in presence of CO2 more than in its absence.  Non-recombinant bacterium in this medium produced 18.30 and 30.63 percent PHB less than the recombinant cell in the presence and absence of CO2, respectively. The quantity of PHB production using GC-MS revealed that CA gene expression was effective for increasing PHB production in recombinant R. eutropha. In the presence of CO2 and by using a simple medium. The recombinant bacterium is able to produce PHB. This bacterium can also be effective in carbon sequestration.

Bracket fungi are the most important macroscopic fungi that play a main role in the ecosystem. In this study, the morphological characters of Cerrena unicolor were evaluated and then, the effect of different solvents (n-Hexan, Dichloromethane, Ethyl acetate, and Methanol) on the extraction of phenolic compounds, antioxidant properties, and cytotoxic activities of the extracts were investigated. Total phenol and flavonoid content, phenolic acid analysis, antioxidant properties, and cytotoxic activities on MCF-7 cells were evaluated by spectrophotometry, HPLC, DPPH, and MTT methods, respectively. The obtained results showed the basidiocarp was semicircular and wavy, and the upper surface was covered with small white to grayish brown hairs. Basidia were 25 µm in length, calvate and including 4 sterigmata with ellipsoid basidiospores. The results also indicated that the Methanolic extract had the highest total phenol and flavonoid contents compared with other extracts. Moreover,Benzoic acid, Protocatechuic acid, Gallic acid, and Cinnamic acid were the main phenolic acids of the Methanolic and Ethyl acetate extracts. In addition, the Methanolic extract showed the highest antioxidant activity in inhibiting DPPH radicals, while the Methanolic and Ethyl acetate extracts indicated the highest cytotoxic activity on MCF-7 cells. Therefore the Methanolic extract due to phenolic compounds could be proposed as a new sourceofnatural antioxidants with cytotoxic activity.