排序方式： 共有111条查询结果，搜索用时 31 毫秒
31.
Najmeh Zarei Hosnieh Ghasemi Mahsa Nayebhashemi Mozhgan Zahmatkesh Monire Jamalkhah Nafiseh Moeinian Zahra Mohammadi Somayeh Enayati Vahid Khalaj 《Iranian Biomedical Journal》2021,25(4):255
Background:The methylotrophic yeast Pichia pastoris is an appealing production host for a variety of recombinant proteins, including biologics. In this sense, various genetic- and non-genetic-based techniques have been implemented to improve the production efficiency of this expression platform. Los1 (loss of supression) encodes a non-essential nuclear tRNA exporter in Saccharomyces cerevisiae, which its deletion extends RLS. Herein, a los1-deficient strain of P. pastoris was generated and characterized. Methods:A gene disruption cassette was prepared and transformed into an anti-CD22-expressing strain of P. pastoris. A δ los1 mutant was isolated and confirmed. The drug sensitivity of the mutant was also assessed. The growth pattern and the level of anti-CD22 ScFv expression were compared between the parent and mutant strains.Results:The los1 homologue was found to be a non-essential gene in P. pastoris. Furthermore, the susceptibility of los1 deletion strain to protein synthesis inhibitors was altered. This strain showed an approximately 1.85-fold increase in the extracellular level of anti-CD22 scFv (p < 0.05). The maximum concentrations of total proteins secreted by δ los1 and parent strains were 125 mg/L and 68 mg/L, respectively.Conclusion:The presented data suggest that the targeted disruption of los1 homologue in P. pastoris can result in a higher expression level of our target protein. Findings of this study may improve the current strategies used in optimizing the productivity of recombinant P. pastoris strains. Key Words: Aging, Longevity, Pichia pastoris, Recombinant proteins 相似文献
32.
Houri Edalat Zahra Hajebrahimi Vahid Pirhajati Mansoureh Movahedin Mahmoud Tavallaei Mohammad-Reza Soroush Seyed Javad Mowla 《Iranian Biomedical Journal》2013,17(3):140-145
Background: Bone marrow stromal cells (BMSC) have been successfully employed for movement deficit recovery in spinal cord injury (SCI) rat models. One of the unsettled problems in cell transplantation is the relative high proportion of cell death, specifically after neural differentiation. According to our previous studies, p75 receptor, known as the death receptor, is only expressed in BMSC in a time window of 6-12 hours following neural induction. Moreover, we have recently reported a decreased level of apoptosis in p75-suppressed BMSC in vitro. Therefore, our objective in this research was to explore the functional effects of transplanting p75:siRNA expressing BMSC in SCI rats. Methods: Laminectomy was performed at L1 vertebra level to expose spinal cord for contusion using weight-drop method. PBS-treated SCI rats (group one) were used as negative controls, in which cavitations were observed 10 weeks after SCI. pRNA-U6.1/Hygro- (group two, as a mock) and pRNA-U6.1/Hygro-p75 shRNA- (group three) transfected BMSC were labeled with a fluorescent dye, CM-DiI, and grafted into the lesion site 7 days after surgery. The Basso-Beattie-Bresnehan locomotor rating scale was performed weekly for 10 weeks. Results: There was a significant difference (P≤0.05) between all groups of treated rats regarding functional recovery. Specifically, the discrepancy among p75 siRNA and mock-transfected BMSC was statistically significant. P75 siRNA BMSC also revealed a higher level of in vivo survival compared to the mock BMSC. Conclusion: Our data suggest that genetically modified BMSC that express p75:siRNA could be a more suitable source of cells for treatment of SCI. Key Words: Spinal cord injury (SCI), Apoptosis, Bone marrow stromal cells (BMSC) 相似文献
33.
This experiment was conducted to evaluate the effects of three nutrient recipes containing different concentrations of macronutrients in the vegetative stage [Vegetative Nutrient Solution: (VNS-I, VNS-II, and VNS-III)] and two nutrient recipes in reproductive stage [Reproductive Nutrient Solution: (RNS-I and RNS-II)], on physiological and biochemical parameters of strawberry ‘Paros’ in a soilless system. The results indicated the significant effects of nutrient solution on the photosynthetic capacity, yield, minerals uptake and titratable acidity of strawberry fruits. In the other hand fruit total soluble solids affected by vegetative nutrient solution. The highest yield was obtained under application of lowest level of minerals. Vegetative growth including leaf number and leaf area, as well as total chlorophyll were the highest as potassium (K+), calcium (Ca2+), and nitrogen (N) concentrations were increased. The highest content of N and Ca2+ uptake were in VNS-III × RNS-I formulation. Additionally, the highest vitamin C was in VNS-I formulation. Moreover, the most firmed fruits and the highest post-harvest shelf life of fruits were produced in VNS-III × RNS-I formulation. 相似文献
34.
Sayedeh Saba Bilgrami Saadollah Houshmand Mahdi Kadivar Baratali Fakheri Vahid Shariati 《Archives of Agronomy and Soil Science》2018,64(3):331-346
Micronutrient deficiency is one of the most common and widespread nutritional issues. Among the factors mitigating the bioavailability of Zn (zinc) and Fe (iron), phytic acid plays a key role; therefore, in order to scrutinize genetic alterations ?related to micronutrient and phytate contents, we examined the concentrations of zinc, iron, and phytic acid, as well as its mole ratio to ?zinc in various wheat species grown in two planting seasons. The concentrations of phytic acid and its mole ratio to zinc were 0.61?1.55 g kg?1 dry weight and 1.88?4.17 for autumn, and 0.97?2.02 g kg?1 dry weight and 2.10?4.05 for spring planting. There was a significant discrepancy among wheat species; tritipyrum had the highest concentration of iron, phytic acid and its mole ratio to zinc, and T. monococcum and T. aestivum recorded reasonable zinc bioavailability. Correlation studies between grain phytic acid concentrations and other measured traits revealed various relationships, denoting an irrefutable impact of planting season and wheat ploidy levels on modification of wheat genotypes. The characters contributing more positively with principal component (PC) 1 were Zn and Fe under spring planting and Fe under autumn planting. Spike number per square meter, biological yield and grain yield in spring cultivation, and grain zinc concentration in autumn cultivation were positively correlated to principal component (PC) 2. Given that the concentration of Fe and Zn in all the studied genotypes is relatively high and due to the existence of other desirable agronomic traits, this study believes that it could possibly enhance the applicability of some of these genotypes for breeding purposes. 相似文献
35.
Field experiments were conducted to investigate the effects of irrigation regimes and N levels on assimilate remobilization of two barley cultivars (Yousefsix-rowed and Nimrouztwo-rowed) in 2011 and 2012. There were three levels of water regimes (full irrigation (I100), 75% and 50% of I100: I75 and I50, respectively) in 2011. Rain-fed treatment (I0) was included in 2012. Three N levels (0, 60, and 120 kg ha?1) were used. Grain yield and assimilate remobilization decreased by severe water stress (I0), however, the reduction of them were intensified by N fertilizer application. The N remobilization was negatively affected by N fertilization and water stress. The two-rowed showed higher N remobilization (10.7%) and contribution of N remobilized to N content of grain (5.8%) than the six-rowed. The two-rowed cultivar showed significantly higher assimilate remobilization and grain yield than the six-rowed under I50 (26.3% and 6.5%, respectively) and I0 (48.7% and 17.1%, respectively), while the six-rowed had similar or higher performances in terms of these traits under I100 and I75. This study showed that optimizing irrigation and N rates (decrease N level with increasing water stress) and selection of the suitable cultivars (Nimrouztwo-rowed) might increase assimilate remobilization and consequently grain yield under drought stress conditions. 相似文献
36.
Masume Kamali Najafabad Mohammad Reza Imanpoor Vahid Taghizadeh Alireza Alishahi 《Fish physiology and biochemistry》2016,42(4):1063-1071
This study was conducted to investigate the effects of dietary chitosan on growth performance, hematological parameters, intestinal histology, stress resistance and body composition in the Caspian kutum (Rutilus frisii kutum, Kamenskii, 1901) fingerlings. Fish (1.7 ± 0.15 g) were fed diets containing chitosan at different levels (0, 0.25, 0.5, 1 and 2 g kg?1 diet) for a period of 60 days. Results showed that the feed conversion ratio significantly decreased in fish fed diet containing 1 g kg?1 of chitosan compared to the other groups (P < 0.05), but there were no significant differences between treatments in terms of specific growth rate and condition factor (P > 0.05). Leukocyte increased in fish fed diet containing 2 g kg?1 of chitosan compared to the other groups (P < 0.05). Lymphocytes, eosinophils and neutrophils did not significantly change among dietary treatments (P > 0.05). Also, the chitosan supplementation did not affect the whole-fish body composition (P > 0.05). Light microscopy demonstrated that the intestinal villus length increased in fish fed diet containing 1 g kg?1 of chitosan compared to control group (P < 0.05). While 11 and 13 ‰ salinity and 30 °C thermal stress had no effect, 1 g kg?1 of chitosan (P < 0.05) showed highest survival rate (70 %) in 34 °C thermal stress. The results showed that chitosan in the diet of the Caspian kutum fingerlings could improve feed conversion ratio, the nonspecific defense mechanisms and resistance to some of the environmental stresses. 相似文献
37.
Farhad Azarmi Atajan Vahid Mozafari Payman Abbaszadeh-Dahaji Mohsen Hamidpour 《Communications in Soil Science and Plant Analysis》2019,50(7):894-908
Enhancement of manganese (Mn) availability in saline and Mn-deficient soils is very important for plant growth. An experiment was carried out to evaluate the effect of Pseudomonas sp. rhizobacteria (P0 (control), P1, P2 and P3) and Mn (0 and 10 mg Mn kg?1 soil) on the distribution of Mn in the rhizosphere of pistachio seedlings under salinity stress (0, 1000 and 2000 mg NaCl kg?1 soil). The results showed that salinity decreased the dry weight, Mn uptake and chlorophyll content of the pistachio seedlings. However, inoculation with rhizobacteria increased these parameters in saline conditions. Application of rhizobacteria increased the availability of Mn in the rhizosphere soil. The use of rhizobacteria decreased the residual-Mn form in the rhizosphere. Inoculation with rhizobacteria increased the percent of Mn2+ and MnCl+ species in the soil solution. However, pistachio seedlings inoculation with rhizobacteria increased the contents of Mn available forms in the rhizosphere soil. 相似文献
38.
Vahid Mahdavi Hooshang Rafiee-Dastjerdi Asadollah Asadi Jabraeil Razmjou Bahram Fathi Achachlouei Shizuo George Kamita 《American Journal of Potato Research》2017,94(6):647-657
Phthorimaea operculella (Zeller) is one of the most common insect pests of cultivated potato in tropical and subtropical regions. In this research, a potential strategy to improve the insecticidal activity of plant essential oils for the effective management of P. operculella was studied. The insecticidal and residual effects of nanofiber oil (NFO) and pure essential oil (PEO) of Cinnamomum zeylanicum were assessed on PTM under laboratory conditions. The nanofibers were made by the electrospinning method using polyvinyl alcohol (PVA) polymer. The morphological characteristics of the nanofibers were evaluated by scanning electron microscopy and Fourier transform infrared spectroscopy. The chemical constituents of cinnamon essential oil (EO) were detected by GC/MS. Fumigant toxicity of NFO and PEO were evaluated on different growth stages (egg, male and female adults) of P. operculella. SEM and FTIR analyses confirmed the presence of EO on the nanofiber structure. The yield of the EO from C. zelanicum on the nanofibers was 1.86%. GC/MS analysis showed that cinnamaldehyde was the primary constituent (69.88%) of cinnamon EO. LC50 values of C. zelanicum EO and NFO were 4.92 and 1.76 μl/l air for eggs, 0.444 and 0.212 μl/l air for female adults, and 0.424 and 0.192 μl/l air for male adults, respectively. Fumigant bioassays revealed that NFO was more toxic than C. zeylanicum oil against at all stages of P. operculella. The residual effect of PEO and NFO was evaluated against the egg stage of the P. operculella. NFO lost insecticidal effectiveness 47 days after application, while the efficacy of PEO decreased 15 days after application. Our results suggest that NFO of C. zeylanicum can be used as an effective new tool for the management of P. operculella. 相似文献
39.
Electrospun titanium dioxide nanofibers: Fabrication,properties and its application in photo-oxidative degradation of methyl orange (MO) 总被引：1，自引：0，他引：1
In this study, we synthesed two kind of TiO2 nanomaterial (nanoparticles and nanofiber) for photocatalitic degradation of methyl orange (MO) as pollutant. TiO2 nanoparticles were synthesized by sol-gel technique using titanium (IV) isopropoxide as precursor. Polyvinyl acetate (PVAc)/TiO2 hybrid nanofibers were fabricated by combining sol-gel process with electrospinning technology, which consisted of PVAc as
organic segment and TiO2 as inorganic part. Crystalline phase of TiO2 nanomaterials was investigated by X-ray diffraction (XRD). The XRD results show that the TiO2 nanomaterials crystallize in anatase with some rutile phase and these consist of titanium dioxide nano-crystals. The surface
structures of TiO2 nanomaterials were examined using scanning electron microscopy (SEM). SEM scanning revealed that the nanoparticle and nanofibrous
structure was formed. Fourier transform infrared spectroscopy (FTIR) was employed to analyze the chemical structures of the
PVAc/TiO2 hybrid nanofibers. The FTIR analysis indicated the newly formed associated hydrogen bond because of the hybrid effect between
PVAc and TiO2 sol. Finally, The photooxidative decomposition of methylene blue by using the titania nanomaterials was examined and compared. 相似文献
40.
Paddy and Water Environment - Rice production is one of the largest consumer of water in agriculture. In general, the irrigation water productivity (WPI) is low in paddy fields. In order to improve... 相似文献