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131.
Shahin Emami Wilma Merrill Van Cherington Gisela G. Chiang Michael Kirchgesser Joseph M. Appel Michael Hansen Peter H. Levine Joel S. Greenberger David R. Hurwitz 《In vitro cellular & developmental biology. Animal》1997,33(7):503-511
Summary The ex vivo establishment, expansion, transduction, and reintroduction of autologous bone marrow stromal cells offers a potential efficacious
system for somatic cell gene therapy. It is likely that any ex vivo system will require the use of large numbers of cells which express high levels of transgene products. We present a method
for routine expansion of canine bone marrow stromal cells, established from initial 10–20 ml marrow aspirates, to greater
than 109 cells. This high level expansion of cell cultures uses the stimulatory effect of acidic fibroblast growth factor (aFGF) and
heparin. In the absence of these factors, stromal cell cultures grow actively for only 1 to 2 passages, become flattened in
morphology, and expand to only 108 cells. In the presence of heparin (5 U/ml), aFGF exerts its effect over a wide range of concentrations (0.1–10 ng/ml) in
a dose-dependent manner. The stimulatory effect is dependent on the presence of both aFGF and heparin. Immunocytochemical
and cytochemical analyses phenotypically characterize these stromal cells as bone marrow stromal myofibroblasts. Stromal cells
grown in the presence of aFGF and heparin grow actively and maintain a fibroblast-like morphology for a number of passages,
transduce efficiently with a human growth hormone (hGH) expression vector, and express and secrete high levels of hGH. Human
marrow stromal cells were also established and expanded by the same culture method. This culture method should be of great
value in somatic cell gene therapy for the delivery of secreted gene products to the plasma of large mammals. 相似文献
132.
Adel A. Basyouny Shahin 《Acta zoologica》2006,87(3):215-227
Spermatogenesis and spermatozoon ultrastructure in the Nile electric catfish Malapterurus electricus are described using scanning and transmission electron microscopy. Although the testis organization conforms to the ‘unrestricted’ spermatogonial type, the species has a rare type of spermatogenesis not previously described among catfishes, ‘semicystic’, in which the cyst ruptures before the spermatozoon stage. Spermiogenesis also involves some peculiar features such as condensation of the chromatin in the posterior part of the nucleus to form a compact electron‐dense mass with some irregular electron‐lucent lacunae, while the uppermost part of the nucleus is a loose electron‐lucent area, absence of the nuclear rotation and, as a consequence, the centriolar complex and the initial segment of each flagellum arise directly in a position perpendicular to the basal pole of the nucleus, and occurrence of numerous vesicles in the midpiece. In addition, spermiogenesis includes migration of the diplosome and mitochondria to the basal pole of the nucleus, formation of two moderate nuclear fossae, each of which contains the centriolar complex, development of two independent flagella and elimination of the excess cytoplasm. The mature spermatozoon has a more or less round head with no acrosome or acrosomal vesicle, a long midpiece with numerous mitochondria and vesicles and two long tails or flagella having the classical axoneme structure of 9 + 2 microtubular doublet pattern and with no lateral fins and membranous compartment. These findings suggest that the ultrastructural features of spermiogenesis and spermatozoa of M. electricus are synapomorphies of types I and II spermiogenesis and spermiogenesis is closely similar to the type described in the Nile catfish Chrysichthys auratus. 相似文献
133.
Vahid Molla Kazemiha Shahin Bonakdar Amir Amanzadeh Shahram Azari Arash Memarnejadian Shirin Shahbazi Mohammad Ali Shokrgozar Reza Mahdian 《Cytotechnology》2016,68(4):1063-1080
Mycoplasmas are the most important contaminants of cell cultures throughout the world. They are considered as a major problem in biological studies and biopharmaceutical economic issues. In this study, our aim was to find the best standard technique as a rapid method with high sensitivity, specificity and accuracy for the detection of mycoplasma contamination in the cell lines of the National Cell Bank of Iran. Thirty cell lines suspected to mycoplasma contamination were evaluated by five different techniques including microbial culture, indirect DNA DAPI staining, enzymatic mycoalert® assay, conventional PCR and real-time PCR. Five mycoplasma-contaminated cell lines were assigned as positive controls and five mycoplasma-free cell lines as negative controls. The enzymatic method was performed using the mycoalert® mycoplasma detection kit. Real-time PCR technique was conducted by PromoKine diagnostic kits. In the conventional PCR method, mycoplasma genus-specific primers were designed to analyze the sequences based on a fixed and common region on 16S ribosomal RNA with PCR product size of 425 bp. Mycoplasma contamination was observed in 60, 56.66, 53.33, 46.66 and 33.33 % of 30 different cell cultures by real-time PCR, PCR, enzymatic mycoalert®, indirect DNA DAPI staining and microbial culture methods, respectively. The analysis of the results of the different methods showed that the real-time PCR assay was superior the other methods with the sensitivity, specificity, accuracy, predictive value of positive and negative results of 100 %. These values were 94.44, 100, 96.77, 100 and 92.85 % for the conventional PCR method, respectively. Therefore, this study showed that real-time PCR and PCR assays based on the common sequences in the 16S ribosomal RNA are reliable methods with high sensitivity, specificity and accuracy for detection of mycoplasma contamination in cell cultures and other biological products. 相似文献
134.
Molecular phylogeny of the mainly Mediterranean genera Chaenorhinum,Kickxia and Nanorrhinum (Plantaginaceae,tribe Antirrhineae), with focus on taxa in the Flora Iranica region 下载免费PDF全文
Plantaginaceae tribe Antirrhineae as revised by Sutton (1988) comprises about 30 genera that have undergone significant taxonomic changes in recent years, many of which have yet to be assessed by detailed phylogenetic analyses, including Kickxia, Nanorrhinum and Chaenorhinum. To examine the monophyly, relationships and rank of Kickxia, Nanorrhinum and Chaenorhinum, we conducted a phylogenetic analyses of the nuclear ribosomal DNA internal transcribed spacer region (ITS) and chloroplast DNA (rpl32‐trnL) sequence data, with special focus on the Flora Iranica region. We sampled 22 species of Kickxia s.l. (16 of Kickxia s.s. and 6 of Nanorrhinum), 2 species of Anarrhinum, 12 species of Chaenorhinum, 19 representatives of nine additional genera of Antirrhineae, and several outgroup taxa representing other genera of Plantaginaceae. Parsimony and Bayesian analyses of the two datasets produced almost congruent trees, although taxon sampling differed. Our results indicate that Chaenorhinum can be subdivided into two highly supported groups of species, partially matching two of the currently recognized sections of the genus. Albraunia and Holzneria are nested within the Chaenorhinum clade and should not be recognized as distinct genera. Two clades corresponding to Kickxia sect. Kickxia and Kickxia sect. Valvatae were also highly supported. Our data, whn combined with all other available evidence, support recognition of the clade comprising Kickxia sect. Valvatae at the genus level, as Nanorrhinum. Based on this result, six names are here transferred to Nanorrhinum. A diagnostic key to the seven genera of tribe Antirrhineae known from the Flora Iranica region is also provided. 相似文献
135.
Phosphorus and potassium (K) are major essential macronutrients for biological growth and development. Application of beneficial microorganisms to soil is one approach to enhance crop growth. In this study, the ability of five bacterial strains, including four strains of Pseudomonas sp. (S10-3, S14-3, S19-1, and S21-1) and one strain of Azotobacter sp. SP16, to release K from muscovite and biotite was investigated. Furthermore, phosphate solubilization by these strains was measured when an insoluble source of P [Ca3(PO4)2] was added to the medium. Among the bacterial strains, the highest average K release (73% higher than control) was observed with Pseudomonas sp. S14-3. The average amount of K released from biotite was 37% higher than that from muscovite in inoculated treatments. The enhanced release of mineral K might be attributed to the release of organic acids from the bacteria, a mechanism which plays a pivotal role in solubilizing phosphate from inorganic sources. The results confirmed the enhanced phosphate solubilization by the bacterial strains in the presence of muscovite. The highest P solubilizing activity (67% higher than control) was found in S21-1 and S14-3 strains. Concentrations of both K and P in the liquid phase were increased by increasing the time of experiment. X-ray diffraction analysis of muscovite specimens inoculated with S14-3 strain revealed a partial transformation of these minerals through the presence of 19.5 Å peak on the diffractogram of the magnesium-saturated sample. This may be due to the release of K from the interlayer space and subsequent filling with a number of bacterial metabolites. The findings of this research suggest K depletion from mica in the presence of bacteria, but further investigations are needed to clarify the mechanisms involved. 相似文献
136.
137.
Maria J. Mota Rita P. Lopes Mohamed Koubaa Shahin Roohinejad Francisco J. Barba Ivonne Delgadillo 《Critical reviews in biotechnology》2018,38(1):122-140
The interest in improving the yield and productivity values of relevant microbial fermentations is an increasingly important issue for the scientific community. Therefore, several strategies have been tested for the stimulation of microbial growth and manipulation of their metabolic behavior. One promising approach involves the performance of fermentative processes during non-conventional conditions, which includes high pressure (HP), electric fields (EF) and ultrasound (US). These advanced technologies are usually applied for microbial inactivation in the context of food processing. However, the approach described in this study focuses on the use of these technologies at sub-lethal levels, since the aim is microbial growth and fermentation under these stress conditions. During these sub-lethal conditions, microbial strains develop specific genetic, physiologic and metabolic stress responses, possibly leading to fermentation products and processes with novel characteristics. In some cases, these modifications can represent considerable improvements, such as increased yields, productivities and fermentation rates, lower accumulation of by-products and/or production of different compounds. Although several studies report the successful application of these technologies during the fermentation processes, information on this subject is still scarce and poorly understood. For that reason, the present review paper intends to assemble and discuss the main findings reported in the literature to date, and aims to stimulate interest and encourage further developments in this field. 相似文献
138.
A. J. Trulson R. B. Simpson E. A. Shahin 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1986,73(1):11-15
Summary Transgenic cucumber plants (Cucumis sativus L., cv. Straight Eight) were regenerated from roots induced by inoculation of inverted hypocotyl sections with Agrobacterium rhizogenes containing the vector pARC8 in addition to the resident Ri-plasmid. The DNA transferred to the plant from the vector (T-DNA) included a gene which encoded the enzyme neomycin phosphotransferase II, and thus conferred on the plant cells resistance to kanamycin. The transgenic plants looked normal and were positive for the neomycin phosphotransferase II. Southern blot analysis of the transgenic plants revealed that all plants contained vector DNA, but only some of them contained DNA from the Ri plasmid. 相似文献
139.
Annie Prost Shahin Emami Gabriel Rosselin Christian Gespach 《Bioscience reports》1984,4(12):1045-1050
In the presence of 3-isobutyi-l-methylxanthine, VIP produced a dose-related (3×10–9–10–7 M) increase (g-fold) in cAMP production in isolated HEp-2 cells incubated at 15°C in KRP buffer. Among the peptides structurally related to VIP, including secretin (10–7 M), pancreatic glucagon (10–6 M), PHI, somatostatin-14 (10–6 M), hpGRF (10–8–4×10–M), GIP (2×10–7 M), only PHI (3×10–7 M and above) is able to activate the cAMP-generating system in HEp-2 cells, but at 102 times lower potency. Under the same conditions, histamine (10–3 M) was also ineffective, while PGE 2 (10–7–10–4 M) increased (0-fold) basal cAMP levels in HEp-2 cells. The VIP effect is related to the interaction os the peptide on VIP recognition sites (12SI-VIP-binding capacity ), coupled to the membrane-bound adenylate cyclase . The results indicate that the transformed laryngeal cell line HEp-2 possessesa receptor-cAMP system preferentially activated by VIP (relative potencies: VIP > PHI other peptides of the secretin family), and suggest that this neuropeptide could modulate biological functions in normal laryngeal epithelia in man. 相似文献
140.