نشریه یافته های نوین در علوم زیستی
سال ششم شماره 4 (پیاپی 22، زمستان 1398)

One of the most important factors related to male fertility is sperm chromatin status. Under Assisted Reproductive Techniques (ART), especially Intracytoplasmic Sperm Injection (ICSI), the natural selection of high quality sperm with intact chromatin is not possible. Therefore, embryo quality and pregnancy rate decreased for damaged DNA of sperms involved in the fertilization of eggs. Thus, this study evaluated the frequency of abnormal sperm chromatin condensation and damaged sperm chromatin in men with different infertility factors (e.g. oligozoospermia, asthenozoospermia, teratozoospermia, oligasthenoteratozoospermia, and normozoospermia) and ICSI outcomes were examined. 195 patients were examined and the sperm chromatin status was evaluated using aniline blue and toluidine blue staining. Fertilization, zygote and embryo quality, chemical pregnancy and abortion rates were calculated, too. The results showed that in the oligoasthenoteratozzoospermia samples, the damaged chromatin percentage was higher than that in normozoospermia ones. The fertilization rate, embryo quality, and pregnancy rate significantly decreased in this group. Also, a higher abortion rate was observed in this group (P<0.05). In conclusion, the frequency of damaged chromatin was observed to be different in different male infertility factors, which could influence the ICSI outcomes. Therefore, the evaluation of sperm chromatin status before cycle initiation was found to promote ICSI outcomes.

Yersinia pestis, a gram-negative rod belonging to the Enterobacteriaceae family, is the causative agent of plague. Classical methods of detecting the organisms are time-consuming, expensive and dangerous. The aim of the study was to design a Real-time PCR assay on the basis of the pla gene of Yersinia pestis. In this research the Real- time PCR test was optimized by using special primers for targeting pla gene. After preparing 10-fold serial dilutions of the pla and their analysis by the assay, the last dilution showing a fluorescent signal was confirmed as the limit of detection (LOD). A standard curve based on the Ct values was depicted, so the assay was developed to quantify the target gene. The analytical specificity was determined by subjecting the genome of some control negative bacteria to the assay. In this experiment, negative control genomes did not show detectable signals in the assay. The last dilution of pla plasmid which showed a fluorescent signal was 4.5 fg. So, the lower detectable copy numbers of the gene in a 20 μl PCR reaction was calculated as 1×103.

In order to investigate the differences in the shape of the big-head and two morphotypes of Phytophagous fish by geometric morphometric technique, 30 samples of each group, with a mean standard length of 25 ± 3 cm, were prepared. After fish were anesthetized by 1% Clove powder extract and stabilized in formalin buffer 4%, 6-megapixel digital images of the left profile of the specimens were prepared. A total of 17 morphological landmarks were digitized by tpsDig2 software and the tps files were prepared. All non-shaped data were removed from landmark coordinates by generalized procrustes analysis. After the approval of regression between shape space and tangent space, data were analyzed using Principal Component (PCA), Canonical Variation (CVA) and Cluster Analyzes (CA) methods in PAST and TPS series. According to the results, the head length and height, the size of dorsal fin, the length of pre ventral distance, the height of caudal peduncle and the degree of posterior position of the pectoral fin in bighead carp, are some of the distinctive morphological features among species, mainly related to their ecological niche (specially feeding strategies). In the case of silver carp variants, the posterior position of pectoral fin base in silver carp-R that is close to bighead carp, may be due to hybridization between bighead carp and silver carps.

Magentotactic bacteria are the types of bacteria capable of orientation in an external magnetic field because of the ability to produce structures called magnetosomes. Magnetosomes, nanometer-scale structures, are present in most of the magnetotactice bacteria. They are intracellular organelles composed of magnetic iron mineral crystals individually surrounded by a phospholipid layer. Because of the unique features of magnetosomes, magentotactic bacteria have become the fascinating subject of research in many research and applied fields of study, including robotics, medicine, biology, environment and geology. In this review, we have tried to introduce magentotactic bacteria, the formation of magnetosomes and their structures, in order to highlight the importance of these bacteria. Finally, some applications of these bacteria in different areas of research, e.g. targeted drug delivery, cancer treatment and removal of heavy metals from water, were described in order that a better understanding of their applications could be obtained.

Phosphorus, the most essential nutrient for plants, becomes quickly unavailable for the plants in the soil. Phosphate solubilizing bacteria (PSB( can play an important role in providing Phosphorus for plants. In this study, the PSBs were screened from plant rhizosphere by Pikovskaya method. Then, the growth rate and phosphate solubilizing ability of 9 superior strains were measured at different temperatures and levels of salinity and pH. The best strain was identified by 16S rDNA gene sequence analysis. Finally, the genetic diversity of phosphate solubilizing strains were examined by RAPD markers. Results showed that 25 strains were capable of solubilizing insoluble phosphates among the 57 isolates studied. Of the nine superior strains, Cke1 had the highest solubilizing index with the average growth rate under all conditions and was introduced as the best PSB strain identified in the present study. 16S rDNA gene sequence analysis showed that this strain belonged to the Enterobacter genus. The results of genetic variation showed that all stains were divided into six groups and three strains that had the lowest similarity with other strains were placed in three separate groups. Given that Cke1 strain has the ability of solubilizing the insoluble phosphate in different stresses, it can be a good candidate for providing phosphorus at temperatures of 30 and 35 °C, 1.2% and 1.8% salinity levels and pH levels of 6 and 8 for the crops.

Nowadays plant endophytic bacteria have found diverse and useful applications in biotechnology; therefore, much attention has been paid to the isolation, identification, and evaluation of these microorganisms. Since the sterilizing plant tissue surfaces from epiphytic bacteria is difficulty, the efficacy of three different screening methods for endophytic bacteria including 1- HClO sterilization, 2- Periodic sterilization (modified tyndallization) and 3- Triton X100 and HClO sterilization, was evaluated in this study. The modified Tyndallization is an innovative method used in this study to appropriately remove the internal spores of epiphytic bacteria, considered to be an obstacle to the isolation of endophytes. Most of the endophytic bacteria were isolated from dicotyledons and leaves. Endophytic bacteria were also studied for the production of different hydrolase enzymes, whereas the protease enzyme was produced in a wide range of endophytic bacteria in greater quantities than other enzymes. The EndoA strain was molecularly identified and found to be 100% similar to Bacillus halotolerans.

Antioxidant enzymes play an important role in plant defense against pathogenic agents. Following the identification of the pathogen, plants produce active oxygen species (ROS) as one of their first defense responses. To maintain the balance of ROS levels and prevent their harmful effects, plants produce antioxidant peroxidase (POX), catalase (CAT), ascorbate peroxidase (APX) and superoxide dismutase (SOD) enzymes. In the present study, the resistance of bean plants cultivars, namely Sadri, Paak, Darakhshan and Dorsa, to Xanthomonas axonopodis pv. phaseoli (Xap) were studied in greenhouse conditions. The catalase, peroxidase and ascorbate peroxidase enzyme activities were studied in healthy and Xap-infected bean cultivars Sadri and Derakhshan at 0, 24, 48, 72 hours and 20 days post inoculation by a completely randomized design with 5 treatments and 4 replications. The result showed that disease symptoms appeared in all tested cultivars. Derakhshan and Sadri cultivars, with 58.33 and 80.56 percentages of infected plants 20 days after inoculation, showed the least and highest infection rates, respectively. The highest catalase and peroxidase activities were recorded 24 and 48h post inoculation. These records reduced 48 and 72 hours post inoculation, respectively. The activities of these two enzymes in the susceptible cultivar were less than those in the semi-resistant one. The chlorophyll a and chlorophyll b contents of Xap-infected plants reduced significantly. The total chlorophyll content of uninfected Sadri and Darakhshan cultivars were 2.93 and 3.23 µg/g, respectively, which reduced to 1.96 and 2.14 µg/g of leaf tissue in infected plants, respectively. Based on these results, it is suggested that the Derakhshan cultivar should be planted in disease-susceptible regions as the semi-resistant cultivar.

Some rhizobacteria have positive effects on plants growth. Syrian bean-caper (Zygophyllum fabago) is a weed plant with medicinal value. This study was conducted to isolate and identify bacteria from Syrian bean-caper rhizosphere. Characteristics associated with plant growth stimulation, such as phosphate and zinc dissolution, production of Indole acetic acid and antifungal activity, were investigated. The isolates were separately inoculated to the plant and after plant root establishment was ensured, their effectiveness in increasing plant growth in greenhouse conditions was measured. Biochemical and molecular identification results showed that five isolates belonged to the genera Bacillus, Pseudomonas, Pantoea, and Brevibacterium. All five isolates showed some degree of plant growth promotion capabilities. Among the isolates, only the genus Bacillus increased the dry weights of plants significantly. The amount of phosphate solubilization for this isolate was 440 μg ml-1 and its acid production in the culture medium was higher than that in other isolates. The isolate had zinc solubilisation capability and produced 3.89 mg ml-1 indole acetic acid. However, this isolate did not show antifungal activity against two fungal pathogens of Aspergillus niger and Botrytis cinerea.

The aim of this study was to evaluate the antibacterial activity of the water extracts of three species of Salvia (S. perspolitana, S. palaestina, S. bracteata) on Staphylococcus aureus, Escherichia coli and Pseudomonas aeroginosa. The antibacterial activity of water extracts of the studied species on the bacterial strains was examined using well diffusion method and minimum inhibitory concentration (MIC). Results showed that only S. bracteata formed growth inhibitory zone (9 mm) on Staphylococcus aureus. The extracts of all three plants formed growth inhibitory zone on E.coli and P. aeroginosa. The extract of S. bracteata was more effective than that of the other species. Results for MIC also showed that the extracts of S. perspolitana had the lowest effect on St. aureus and its MIC was observed in a concentration of 1024 µg/ml. The extracts of this species had the inhibitory effect in a concentration of 256 µg/ml. The uppermost inhibitory effect was provided by the extract of S. bracteata, since the minimum inhibitory concentration of this species for S. aureus was equal to 64 µg/ml; and for the other two bacteria, it was equal to 128 µg/ml. The extracts of S. palaestina had the lowest effect on S. aureus and its MIC was observed in a concentration of 1024 µg/ml. The extracts of this species had an MIC equal to 512 µg/ml for the other two bacteria. It was concluded that S. bracreata could be considered a suitable species with anti-bacterial activities in future researches.

Plants have been used as medicines in the treatment of diseases from the past to present. In this research, the anti-microbial effects of aqueous and methanolic extracts of Erythrostemon gilliesii were studied. For this purpose, fresh flowers were ground and then macerated in methanol 100% and water overnight. After the evaporation of solvents, anti-microbial activities of the concentrated extracts were evaluated by the well-diffusion method on Klebsiella pneumoniae, Pseudomonas aeroginosa, Methicilin resistance, Staphylococcus aureus, Bacillus subtilis and Candida albicans. The results showed that the extracts were effective on different bacteria and yeasts. In order to determine the minimum inhibitory concentration (MIC) and minimum biocidal concentration (MBC), anti-microbial tests were performed in micro-plates. Subsequently, the results indicated that the extracts were stable at different temperatures. The aqueous and methanolic extracts of the flowers of E. gilliesii had exhibited anti-microbial effects against important infectious microbes and could be introduced as an excellent source for anti-microbial agents.

The cement production activities leads to the release of different pollutants into the environment. This research was conducted to study the effects of dust particles released by Behbahan cement factory on the absorption of some nutrient elements and biochemical parameters in dominant herbaceous species grown in this area, including Bromus tectorum, Malva neglecta and Sinapis arvensis. Plant samples were transferred to the laboratory. Then, the concentrations of some nutrient elements, such as Fe, Cu, Zn, K, Mn, P and N, were assayed in plant and soil samples. Moreover, some biochemical parameters, such as photosynthetic pigments, total protein, soluble carbohydrates, proline, relative water content, leaf pH total ascorbate and air pollution tolerance indexes (APTI), were evaluated. Based on these results, it is supposed that three plant species are tolerant to air pollution with an APTI higher than 16. In addition, it seems that the dust released by the cement factory has not led to a toxic accumulation of the elements in the studied plants. The deficiency of Mn and P was determined for three plant species. On the basis of biochemical analysis, it is supposed that these plant species possibly use different strategies to tolerate the pollutants in this area.

To investigate the effect of herbicide Trifluralin and the role of magnetized water on enzymatic activities and content of proline and growth substances including gibberellin (GA3) and cytokinin (6- benzyl amino purine), an experiment was conducted using squash (Cucurbita pepo L. var. Shiraz Hybrid F1) seedlings. Four levels of trifluralin (0, 5, 15 and 25 ppm) and irrigation by distilled and magnetized water were applied in a completely randomized design in 3 replicates at Urmia University in 2016. Different levels of trifluralin were added to pots 2 days after planting. Seedlings were treated by modified Hoagland solution with diurnal temperature 30:18 °C, relative humidity of 70-80 percent and light period of 16:8 hr, during a 5-week growing period in growth chamber. The effect of magnetized water and trifluralin on ornithine amino-transferase (OAT), proline dehydrogenase (PDH) and content of proline in both shoots and roots as well as GA3 and cytokinin was significant (p>0.01) according to ANOVA. The content of proline and OAT in roots and shoots as well as GA3 and cytokinin increased significantly, although the PDH of roots and shoots decreased under the influence of magnetized water. The content of proline and OAT increased and GA3, cytokinin and the activity of PDH declined by the increase of the levels of trifluralin. Overall, it can be concluded that the growth and biochemical indices of squash plants were improved by magnetized water under toxicity of herbicide trifluralin.

Aloe vera L. is one of the most valuable plants in the pharmaceutical, cosmetic, sanitary and food industries. In vitro culture is used for commercial production and due to the abundant application of this plant, extensive research has been performed on the in vitro culture of Aloe vera. For this purpose, the present study was conducted at two stages. At the first stage, the best method of sterilization of explants derived from Aloe vera offshoots was investigated. At the second stage, the effect of the type of explants, the light condition (dark and bright) and the effect of BAP (Benzyl Amino Purine) and NAA (α-Naphthalene acetic acid)) growth regulators on regeneration and the amount of phenolic compounds were studied. A factorial experiment was executed on the basis of a completely randomized design with three replications. The best sterilization protocol was 0.1% mercuric chloride (for 2 minutes), 70% ethanol (for 30 seconds) and 15% sodium hypochlorite (for 5 minutes). The little white explant derived from the base of leaves, with the lowest percentage of phenol and the highest survival rate (67.5%) in darkness, was found to be the best candidate. MS medium supplemented with 0.75 mg / L BAP and 0.25 mg / L NAA resulted in the highest stem number (2.5) and stem length (42.107 mm), establishment percentage (73%), leaf number (6.33), leaf diameter (4.8 mm), chlorophyll b (9.216 mg/g) and carotenoids (4.81 mg/g). The highest content of chlorophyll a (56.07 mg/g) and total chlorophyll (61.35 mg/g) were found in samples treated with hormonal medium, supplemented with 1.5 mg / L of BAP with 0.5 mg / L of NAA. The maximum number (3) and average length (33.3 mm) of roots were observed in samples treated with the hormone-free medium.

The purpose of this research was to identify the structural adaptations in three populations of Convolvulus persicus L. on coastal areas in Mazandaran Province, whose populations of which are severely reducing due to the intense environmental stresses of the coastal zone. In general, annular collenchyma, isobilateral mesophyll, amphiphloic siphonostele, abundant presence of laticiferous tubes, numerous druse crystals and the presence of periderm in rhizome can be introduced as the most important morpho-anatomical strategies utilized against harsh environmental conditions. Sari population was foud to have the most various structural toleration mechanisms in comparison with Babolsar and Nour populations. Few differences were observed in anatomical characteristics in the three populations of Convolvulus persicus as the evidence for high intra-specific phenotypic variability, leading to local adaptation and increase of the tolerability of plants against environmental changes.

The phylogenetic relationships among 39 species belonging to 12 sections of Astragalus from Iran were studied on the basis of 29 morphological characters. The cladistics analysis of the morphological data was performed using PAUP* 4.0b10 program. The obtained data were compared with the molecular systematics data obtained from nuclear DNA ITS. In contrast with previous molecular systematic studies, the morphological data placed the sect. Caraganella as paraphyletic clade to the sects. Cenantrum, Nuculiella, and Eremophysa. Our results were similar to those obtained by previous molecular systematic studies which specified sects. Astragalus, Alopecuroidei and Laxiflori as paraphyletic clades. In accordance with data presented in previous molecular systematic studies, the species of the sect. Caprini showed close relationship with those in sects. Pelta and Pendulina. The present analysis, consistent with molecular systematic studies, rejected the monophyly of most sections studied. Therefore, although the circumscription of those sections needs to be carried out on the basis of the results of widely accepted molecular and morphological phylogenetic studies, future studies are needed to clarify and resolve some remaining ambiguities.