排序方式: 共有150条查询结果,搜索用时 140 毫秒
91.
Nasser Masroori Raheleh Halabian Mahshid Mohammadipour Amaneh Mohammadi Roushandeh Mahdi Rouhbakhsh Ali Jahanian Najafabadi Mahdi Edalati Fathabad Mohamad Salimi Mohamad Ali Shokrgozar Mehryar Habibi Roudkenar 《Biotechnology letters》2010,32(6):803-809
Recombinant coagulation factor VII (FVII) is used as a potential therapeutic intervention in hemophilia patients who produce
antibodies against the coagulation factors. Mammalian cell lines provide low levels of expression, however, the Spodoptera frugiperda Sf9 cell line and baculovirus expression system are powerful systems for high-level expression of recombinant proteins, but
due to the lack of endogenous vitamin K-dependent carboxylase, expression of functional FVII using this system is impossible.
In the present study, we report a simple but versatile method to overcome the defect for high-level expression of the functional
recombinant coagulation FVII in Sf9 cells. This method involves simultaneous expression of both human γ-carboxylase (hGC)
and human FVII genes in the host. It may be possible to express other vitamin K-dependent coagulation factors using this method
in the future. 相似文献
92.
Fahimeh Salimi Kai Zhuang Radhakrishnan Mahadevan Professor 《Biotechnology journal》2010,5(7):726-738
An alternative consolidated bioprocessing approach is the use of a co-culture containing cellulolytic and solventogenic clostridia. It has been demonstrated that the rate of cellulose utilization in the co-culture of Clostridium acetobutylicum and Clostridium cellulolyticum is improved compared to the mono-culture of C. cellulolyticum, suggesting the presence of syntrophy between these two species. However, the metabolic interactions in the co-culture are not well understood. To understand the metabolic interactions in the co-culture, we developed a genome-scale metabolic model of C. cellulolyticum comprising of 431 genes, 621 reactions, and 603 metabolites. The C. cellulolyticum model can successfully predict the chemostat growth and byproduct secretion with cellulose as the substrate. However, a growth arrest phenomenon, which occurs in batch cultures of C. cellulolyticum at cellulose concentrations higher than 6.7 g/L, cannot be predicted by dynamic flux balance analysis due to the lack of understanding of the underlying mechanism. These genome-scale metabolic models of the pure cultures have also been integrated using a community modeling framework to develop a dynamic model of metabolic interactions in the co-culture. Co-culture simulations suggest that cellobiose inhibition cannot be the main factor that is responsible for improved cellulose utilization relative to mono-culture of C. cellulolyticum. 相似文献
93.
Bahman Sharifzadeh Nosrat O. Mahmoodi Manouchehr Mamaghani Khalil Tabatabaeian Alireza Salimi Chirani Iraj Nikokar 《Bioorganic & medicinal chemistry letters》2013,23(2):548-551
A series of novel 2-(3,5-diphenyl-4,5-dihydro-1H-pyrazol-1-yl)-4-phenylthiazoles have been prepared by a three-component cyclo-condensation of various chalcones, thiosemicarbazide and phenacyl bromide. The easy work-up of the products, rapid reaction, and mild conditions are notable features of this protocol. The reaction was efficiently catalyzed in one-pot by a few drops of HCl in EtOH under reflux conditions providing the title compounds in moderate to high yields. The antibacterial activity of the selected products was examined. Some products exhibit promising activities. 相似文献
94.
Masood Sepehrimanesh Mehdi Saeb Saeed Nazifi Nasrin Kazemipour Gholamali Jelodar Saeedeh Saeb 《International journal of biometeorology》2014,58(7):1657-1663
This work analyzes the effects of radiofrequency-electromagnetic field (RF-EMF) exposure on the reproductive system of male rats, assessed by measuring circulating levels of FSH, LH, inhibin B, activin B, prolactin, and testosterone. Twenty adult male Sprague–Dawley rats (180?±?10 g) were exposed to 900 MHz RF-EMF in four equal separated groups. The duration of exposure was 1, 2, and 4 h/day over a period of 30 days and sham-exposed animals were kept under the same environmental conditions as the exposed group except with no RF-EMF exposure. Before the exposure, at 15 and 30 days of exposure, determination of the abovementioned hormone levels was performed using ELISA. At the end of the experiment, FSH and LH values of the long time exposure (LTE) group were significantly higher than the sham-exposed group (p?0.05). Serum activin B and prolactin in the LTE group showed significant increase and inhibin B showed significant decrease than sham and short time exposed (STE) groups after 30 days RF-EMF exposure (p?0.05). Also, a significant decrease in serum testosterone levels in the LTE group was found compared to short and moderate time exposed (MTE) groups after 30 days RF-EMF exposure (p?0.05). Results suggest that reproductive hormone levels are disturbed as a result of RF-EMF exposure and it may possibly affect reproductive functions. However, testosterone and inhibin B concentrations as a fertility marker and spermatogenesis were decreased significantly. 相似文献
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97.
Enayatollah Seydi Zahra Rahimpour Ahmad Salimi Jalal Pourahmad 《Bioorganic & medicinal chemistry》2019,27(24):115163
Flavonoids are natural compounds that show various biological effects, such as the anti-cancer effect. Chrysin is a flavonoid compound found in honey and propolis. Studies have shown that chrysin has anti-cancer activity due to induction of apoptosis signaling. In the present study, we examined the cytotoxic effect of chrysin against liver mitochondria obtained from the hepatocellular carcinoma (HCC) rat model. Diethylnitrosamine (DEN) and 2-acetylaminofluorene (2-AAF) was used for induction of HCC. Mitochondria were isolated from liver hepatocytes using differential centrifugation. Then, hepatocytes and mitochondria markers related to apoptosis signaling were investigated. Our finding indicated an increase in mitochondrial reactive oxygen species (ROS) generation, collapse in the mitochondrial membrane potential (MMP), swelling in mitochondria, and cytochrome c release (about 1.6 fold) after exposure of mitochondria obtained from the HCC rats group with chrysin (10, 20, and 40 µM) compared to the normal rats group. Furthermore, Chrysin was able to increase caspase-3 activity in the HCC rats group (about 2.4 fold) compared to the normal rats group. According to the results, we proposed that chrysin could be considered as a promising complementary therapeutic candidate for the treatment of HCC, but it requires a further in vivo and clinical studies. 相似文献
98.
Micromorphology of fruits and seeds of Iranian Geranium (Geraniaceae), and its systematic significance
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Narjes Salimi Moghadam Shahryar Saeidi Mehrvarz Ania Ahmadian Namin Robabeh Shahi Shavvon 《Nordic Journal of Botany》2015,33(6):673-683
The fruit and seed micromorphology of 22 species of Geranium, representing the eight sections of the genus represented in Iran (G. sectt. Dissecta, Geranium, and Tuberosa of subgen. Geranium; sectt. Batrachioidea, Divaricata, Lucida, Ruberta and Trilopha of subgen. Robertium), have been examined by scanning electron microscopy (SEM). Macro‐ and micromorphological characters, including fruit and seed shape, size, color, hair type and density, mericarp ornamentations, hilum position, seed coat pattern, epidermal cell shape, and anticlinal and periclinal cell walls, are presented. Two microsculpturing patterns are recognized on the mericarp surface: reticulate and pusticulate. The micromorphology of the seed coat showed four distinctive cell patterns. The seed epidermis is constructed either of polygonal, elongated polygonal, or square to rectangular cells. The polygonal type is the most common among the studied species, but the variation in testa cell characters, their size and shape, may provide further information and useful diagnostic characters at specific and infraspecific rank. The shape and color of the seeds are, however, of little systematic value. Fruit characters were found to be important for separating taxa at infrageneric rank and our results show that the species can be separated into subgenera and sections based on fruit morphology. 相似文献
99.
Luigi Ferrucci Marta Gonzalez‐Freire Elisa Fabbri Eleanor Simonsick Toshiko Tanaka Zenobia Moore Shabnam Salimi Felipe Sierra Rafael de Cabo 《Aging cell》2020,19(2)
The global population of individuals over the age of 65 is growing at an unprecedented rate and is expected to reach 1.6 billion by 2050. Most older individuals are affected by multiple chronic diseases, leading to complex drug treatments and increased risk of physical and cognitive disability. Improving or preserving the health and quality of life of these individuals is challenging due to a lack of well‐established clinical guidelines. Physicians are often forced to engage in cycles of “trial and error” that are centered on palliative treatment of symptoms rather than the root cause, often resulting in dubious outcomes. Recently, geroscience challenged this view, proposing that the underlying biological mechanisms of aging are central to the global increase in susceptibility to disease and disability that occurs with aging. In fact, strong correlations have recently been revealed between health dimensions and phenotypes that are typical of aging, especially with autophagy, mitochondrial function, cellular senescence, and DNA methylation. Current research focuses on measuring the pace of aging to identify individuals who are “aging faster” to test and develop interventions that could prevent or delay the progression of multimorbidity and disability with aging. Understanding how the underlying biological mechanisms of aging connect to and impact longitudinal changes in health trajectories offers a unique opportunity to identify resilience mechanisms, their dynamic changes, and their impact on stress responses. Harnessing how to evoke and control resilience mechanisms in individuals with successful aging could lead to writing a new chapter in human medicine. 相似文献
100.
A sensitive electrochemical method for DNA hybridization based on immobilization of DNA probe and [Ru(NH3)5Cl]PF6 complex onto nickel oxide nanomaterials (NiOxnp) modified glassy carbon electrode was developed. Due to strong affinity of NiOxnp for phosphate groups, oligonucleotides probe with a terminal 5′-phosphate group was attached to the surface of the modified electrode. DNA immobilization and hybridization were characterized by electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry using K3Fe(CN)6/K4Fe(CN)6 and [Ru(NH3)5Cl]PF6 as probe and indicator, respectively. The Ru-complex current response indicates only the complementary sequence showing an obvious current signal in comparison to non-complementary and three or single point mismatched sequences. The fabricated biosensor possessed good selectivity and sensitivity for complementary probe, taxon: 32630 tumor necrosis factor (TNF). The linear dynamic range, sensitivity and detection limit of the proposed biosensor were 4 × 10−10 M to 1 × 10−8 M, 34.32 nA nM−1 and 6.8 × 10−11 M, respectively. Excellent reproducibility and stability, quite simple and inexpensive preparation are the other advantages of proposed biosensor. 相似文献