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141.
Adrenocorticotropin and β-lipotropin (β-LPH) have been localized by immunoperoxidase methods in nerve cells and fibers of the hypothalamus and brain stem of the ewe. 6-μm sections were immunostained first for either ACTH or β-LPH. The reaction products and the antibody complexes were then eluted completely from the tissue, and the same section was immunostained for the second peptide. Absorption of the primary antisera with a variety of peptide fragments of ACTH and β-LPH demonstrated, immunocytochemically as well as by radioimmunoassay, that the ACTH and β-LPH antisera were directed to the COOH- and NH(2)-termini of the peptides, respectively. Neither antiserum recognized any portion of the heterologous peptide. In the sequential staining procedure on the same tissue section, preincubation of the antisera with the homologous peptide abolished the staining, whereas preincubation with the heterologous peptide did not affect it, regardless of the order followed. Every nerve cell in the arcuate nucleus that contained ACTH also contained β-LPH, but β-LPH cells appeared, probably falsely, to be twice as numerous as ACTH cells. β-LPH-positive fibers in and beyond the hypothalamus were also more numerous and stained more intensively than ACTH fibers. The salient exception was fibers in the infundibular zona externa, where the opposite was true. Our observations establish that ACTH and β-LPH are contained in the same nerve cells They stongly favor biosynthesis in brain, probably from a common precursor molecule, as has been demonstrated in the pituitary gland. The complexity of the cytologic distribution pattern described suggests that the two peptides are not processed in the same manner by the nerve cell.  相似文献   
142.
143.

Background

The regenerative and immunomodulatory properties of human mesenchymal stromal cells (hMSCs) have raised great hope for their use in cell therapy. However, when intravenously infused, hMSCs fail to reach sites of tissue injury. Fucose addition in α(1,3)-linkage to terminal sialyllactosamines on CD44 creates the molecule known as hematopoietic cell E-/L-selectin ligand (HCELL), programming hMSC binding to E-selectin that is expressed on microvascular endothelial cells of bone marrow (BM), skin and at all sites of inflammation. Here we describe how this modification on BM-derived hMSCs (BM-hMSCs) can be adapted to good manufacturing practice (GMP) standards.

Methods

BM-hMSCs were expanded using xenogenic-free media and exofucosylated using α(1,3)-fucosyltransferases VI (FTVI) or VII (FTVII). Enforced fucosylation converted CD44 into HCELL, and HCELL formation was assessed using Western blot, flow cytometry and cell-binding assays. Untreated (unfucosylated), buffer-treated and exofucosylated BM-hMSCs were each analyzed for cell viability, immunophenotype and differentiation potential, and E-selectin binding stability was assessed at room temperature, at 4°C, and after cryopreservation. Cell product safety was evaluated using microbiological testing, karyotype analysis, and c-Myc messenger RNA (mRNA) expression, and potential effects on genetic reprogramming and in cell signaling were analyzed using gene expression microarrays and receptor tyrosine kinase (RTK) phosphorylation arrays.

Results

Our protocol efficiently generates HCELL on clinical-scale batches of BM-hMSCs. Exofucosylation yields stable HCELL expression for 48 h at 4°C, with retained expression after cell cryopreservation. Cell viability and identity are unaffected by exofucosylation, without changes in gene expression or RTK phosphorylation.

Discussion

The described exofucosylation protocol using xenogenic-free reagents enforces HCELL expression on hMSCs endowing potent E-selectin binding without affecting cell viability or native phenotype. This described protocol is readily scalable for GMP-compliant clinical production.  相似文献   
144.
The plasma membrane of Caldariella acidophila, an extreme thermophilic archaebacterium, is characterized by unusual bipolar lipids. They are based on two C40 ω-ω′ biphytanyl residues, with up to four cyclopentane rings per chain linked to either two glycerols (symmetric lipid) or to one glycerol and to one branched-chain nonitol (asymmetric lipid). When C. acidophila is grown at various temperatures, these lipids show a degree of cyclization of the biphytanyl components which increases as the environmental temperature increases. The rôle of cyclization in determining the temperature adaptation is studied on three lipid samples presenting four, five and six cyclopentane rings per molecule, respectively. Differential scanning calorimetry on the dry asymmetric sample as well as conductance and capacitance measurements on black films have been performed. Both sets of measurements indicate the presence of thermal transitions, three in the hydrated compounds, two in the dry system. The latter are shifted towards higher temperature values as the number of cycles increases. Calorimetric measurements show that two of these transitions are strictly related to the presence of nonitol-containing polar heads. In fact, only a single 10-fold higher transition is detected in the homologous lipid bearing two glycerol polar heads, in the dry as well as in the hydrated form. It is suggested that the two higher-temperature thermal transitions, observed on warming the sample, are induced by the breaking of hydrogen bonds between the nonitol-containing polar heads. By contrast, the lower temperature transition, present only in the hydrated compound and similar to that exhibited by the symmetrical sample, is due to a partial melting of the hydrophobic core. The large change in capacitance observed near the higher transition points by lowering temperature would thus correspond to variations in the dielectric constant due to formation of hydrogen bonds.  相似文献   
145.
Cadmium toxicity in Nostoc UAM208: protection by calcium   总被引:1,自引:0,他引:1  
  相似文献   
146.
A major challenge in controlling overabundant wildlife is monitoring their populations, particularly as they decline to very low density. Camera traps and wildlife detector dogs are increasingly being used for this purpose. We compared the cost-effectiveness of these two approaches for detecting feral cats (Felis catus) on two pastoral properties in Hawke's Bay, North Island, New Zealand. One property was subject to intensive pest removal, while the other had no recent history of pest control. Camera traps and wildlife detector dogs detected cats at similar rates at both sites. The operating costs of each method were also comparable. We identify a number of advantages and disadvantages of each technique, and suggest priorities for further research.  相似文献   
147.
Forage shrub production in the Mediterranean region is frequently limited by soil water availability. To study plant responses to water deficit under such conditions is important for improving crop management and for selecting better yielding forage shrub species. Pre-dawn leaf water potential (Ψpd), plant leaf area (PLA), leaf area per stem (LAs), leaf appearance rate (LAR1;), leaf senescence rate (LSR), individual leaf area (LA) and maximal leaf elongation rate (LER) were studied throughout the year for Medicago arborea (MA) and Medicago citrina (MC) under irrigated (control) and low rainfall field conditions, at the experimental field site of the University of the Balearic Islands in Spain. With irrigation, the highest LA and LER were observed in autumn and spring and the lowest in winter and summer. LAR; was similar for both species in autumn and winter. Throughout the spring, LAR1 was higher for MC compared to MA. PLA was similar for both species during the autumn, winter and spring seasons; however, during the summer PLA of MA was significantly reduced by 53%. This decline was attributed to higher leaf senescence during seed maturity. As a consequence, MC maintained higher leaf area (∼ 5 m2 plant−1) than MA (3 m2 plant−1). Under natural field conditions, soil water deficit increased from February to late August. The main effect of water stress was a marked reduction in LAR1, LA and LER reflected in lower LAs and PLA. Leaf area was severely reduced for both species during the summer, but much more intensively in MA, which developed full leaf senescence. Thus, MC maintained higher PLA than MA (0.5 m2 compared to 0.0 m2). Throughout the year, but especially in the driest months, MC was superior to MA in leaf growth parameters and PLA.  相似文献   
148.
Soil solarisation was consistently efficacious in reducing inoculum density to undetectable levels in a field naturally‐infested with Sclerotium cepivorum. This treatment delayed epidemic onset of white rot of garlic 2–3 months as compared with the untreated control or the inoculation of planting furrows with Glomus intraradices. Furthermore, significant reductions of disease incidence and of the standardised AUDPC were also observed in solarised plots, resulting in quantitative and qualitative yield improvement. Similar effects were observed in plots planted with tebuconazole‐treated cloves, confirming previous results, whereas Trichoderma harzianum was ineffective as a biocontrol agent, when applied to planting furrows. The inoculation of plots with G. intraradices before planting, in three consecutive years, was neither effective for disease control nor on the development of garlic, although the root systems of garlic plants from all the experimental treatments were heavily mycorrhizal at harvest, indicating the presence of native arbuscular mycorrhizal propagules in the soil and their survival after soil solarisation.  相似文献   
149.
Hominins are smaller, slower, and weaker than most large mammals, yet they have been eating meat from freshly killed large mammals since before the invention of sophisticated weaponry. It is thought that they could have achieved this seemingly impossible feat through persistence hunting, a practice powered by endurance running. Essentially, one or more hunters pursue a prey animal in the heat of the day until it reaches the point of hyperthermia. This allows a hunter to safely kill the weakened animal at close range using methods such as beating, strangling, or spearing. The energy balance of this approach to getting food is controversial and has not been calculated previously. We examined the energy costs and gains of persistence hunting through several energy returned on investment (EROI) calculations based on synthesizing available field and laboratory data on the energy used by the hunters and the energy returned from the greater kudu (Tragelaphus strepsiceros). We estimate that the EROI of these hunter-gatherers hunting a kudu ranged from 26:1 to 69:1. The net energy gained from such an effort would sustain an average sized !Kung family for 6.7 to 11.2 days. The “profit” energy within these ranges would have supported the early human societies that practiced persistence hunting, contributing to the often-noted “leisure” characterizing many foraging societies (Sahlins 1974).  相似文献   
150.
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