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161.
Up to now cell-culture based vaccine production processes only reach low productivities. The reasons are: (i) slow cell growth and (ii) low cell concentrations. To address these shortcomings, a quantitative analysis of the process conditions, especially the cell growth and the metabolic capabilities of the host cell line is required. For this purpose a MDCK cell based influenza vaccine production process was investigated. With a segregated growth model four distinct cell growth phases are distinguished in the batch process. In the first phase the cells attach to the surface of the microcarriers and show low metabolic activity. The second phase is characterized by exponential cell growth. In the third phase, preceded by a change in oxygen consumption, contact inhibition leads to a decrease in cell growth. Finally, the last phase before infection shows no further increase in cell numbers. To gain insight into the metabolic activity during these phases, a detailed metabolic model of MDCK cell was developed based on genome information and experimental analysis. The MDCK model was also used to calculate a theoretical flux distribution representing an optimized cell that only consumes a minimum of carbon sources. Comparing this minimum substrate consumption flux distribution to the fluxes estimated from experiments unveiled high overflow metabolism under the applied process conditions. 相似文献
162.
Höhne C Francis RC Pickerodt P Klein A Kaisers U Boemke W 《Canadian journal of physiology and pharmacology》2008,86(6):373-379
The effects of endothelin receptor subtype A (ETA) blockade on hemodynamics and hormonal adaptation during hemorrhage were studied in xenon/remifentanil-anesthetized dogs (n=6) pretreated with an angiotensin II type 1 (AT1)-receptor blocker. Controls: after a baseline awake period, anesthesia was induced in the dogs with propofol and maintained with xenon/remifentanil (baseline anesthesia). Sixty minutes later, 20 mL x kg(-1) of blood was withdrawn within 5 min and the dogs observed for another hour (hemorrhage). AT1 group followed the same protocol as controls except the AT1-receptor blocker losartan (i.v. 100 microg x kg(-1) x min(-1)) was started at the beginning of the experiment. AT1+ETA group was the same as AT1 group but with the addition of the ETA-receptor blocker atrasentan (i.v. 1 mg x kg(-1), then 0.01 mg x kg(-1) x min(-1)). In controls, mean arterial pressure (MAP) remained unchanged during baseline anesthesia, whereas systemic vascular resistance (SVR) increased from 3282+/-281 to 7321+/-803 dyn.s.cm-5, heart rate (HR) decreased from 86+/-4 to 40+/-3 beats x min(-1), and cardiac output (CO) decreased from 2.3+/-0.2 to 0.9+/-0.1 L x min(-1) (p<0.05), with no further changes after hemorrhage. In AT1-inhibited dogs, MAP (71+/-6 mm Hg) and SVR (5939+/-611 dyn x s x cm(-5)) were lower during baseline anesthesia and after hemorrhage, but greater than those in AT1+ETA (66+/-7 mm Hg, 5034+/-658 dyn x s x cm(-5)) (p<0.05). HR and CO were not different between groups. Plasma concentration of vasopressin was highest with AT1+ETA inhibition after hemorrhage. Combined AT1+ETA-receptor blockade impaired vasoconstriction more than did AT1-receptor blockade alone, both during baseline xenon anesthesia and after hemorrhage. Even a large increase in vasoconstrictor hormones could not prevent the decrease in blood pressure and the smaller increase in SVR. Thus, endothelin is an important vasoconstrictor during hemorrhage, and both endothelin and angiotensin II are essential hormones for cardiovascular stabilization after hemorrhage. 相似文献
163.
Hochholdinger F Wen TJ Zimmermann R Chimot-Marolle P da Costa e Silva O Bruce W Lamkey KR Wienand U Schnable PS 《The Plant journal : for cell and molecular biology》2008,54(5):888-898
The rth3 ( roothairless 3 ) mutant is specifically affected in root hair elongation. We report here the cloning of the rth3 gene via a PCR-based strategy (amplification of insertion mutagenized sites) and demonstrate that it encodes a COBRA-like protein that displays all the structural features of a glycosylphosphatidylinositol anchor. Genes of the COBRA family are involved in various types of cell expansion and cell wall biosynthesis. The rth3 gene belongs to a monocot-specific clade of the COBRA gene family comprising two maize and two rice genes. While the rice ( Oryza sativa ) gene OsBC1L1 appears to be orthologous to rth3 based on sequence similarity (86% identity at the protein level) and maize/rice synteny, the maize ( Zea mays L.) rth3-like gene does not appear to be a functional homolog of rth3 based on their distinct expression profiles. Massively parallel signature sequencing analysis detected rth3 expression in all analyzed tissues, but at relatively low levels, with the most abundant expression in primary roots where the root hair phenotype is manifested. In situ hybridization experiments confine rth3 expression to root hair-forming epidermal cells and lateral root primordia. Remarkably, in replicated field trials involving near-isogenic lines, the rth3 mutant conferred significant losses in grain yield. 相似文献
164.
Trichoderma atroviride CBS 349 is able to solubilize lignite. The mould was cultured under non-sterile conditions in a new type of bioreactor for solid substrate fermentation. German lignite (lithotype A, Bergheim) was used as complex solid substrate. Over 40 days 140 g of 1.5 kg lignite held in a 25 l-bioreactor was solubilized by the fungus. 相似文献
165.
Improved nitrogen removal by application of new nitrogen-cycle bacteria 总被引:14,自引:0,他引:14
Jetten Mike S.M. Schmid Markus Schmidt Ingo Wubben Mariska van Dongen Udo Abma Wiebe Sliekers Olav Revsbech Niels Peter Beaumont Hubertus J.E. Ottosen Lars Volcke Eveline Laanbroek H.J. Campos-Gomez Jose Luis Cole Jeff van Loosdrecht Mark Mulder Jan Willem Fuerst John Richardson David van de Pas Katinka Mendez-Pampin Ramon Third Katie Cirpus Irina van Spanning Rob Bollmann Annette Nielsen Lars Peter den Camp Huub Op Schultz Carl Gundersen Jens Vanrolleghem Peter Strous Marc Wagner Michael Kuenen J. Gijs 《Reviews in Environmental Science and Biotechnology》2002,1(1):51-63
In order to meet increasingly stringentEuropean discharge standards, new applicationsand control strategies for the sustainableremoval of ammonia from wastewater have to beimplemented. In this paper we discuss anitrogen removal system based on the processesof partial nitrification and anoxic ammoniaoxidation (anammox). The anammox process offersgreat opportunities to remove ammonia in fullyautotrophic systems with biomass retention. Noorganic carbon is needed in such nitrogenremoval system, since ammonia is used aselectron donor for nitrite reduction. Thenitrite can be produced from ammonia inoxygen-limited biofilm systems or in continuousprocesses without biomass retention. Forsuccessful implementation of the combinedprocesses, accurate biosensors for measuringammonia and nitrite concentrations, insight inthe complex microbial communities involved, andnew control strategies have to be developed andevaluated. 相似文献
166.
167.
This note describes the use of N,N′-carbonyldiimidazole for the coupling of prostaglandins and other carboxylic acids to the amino groups of bovine serum albumin. 相似文献
168.
Stephan J. Linke Andreas Frings Ling Ren Amadeus Gomolka Udo Schumacher Rudolph Reimer Nils-Owe Hansen Nathan Jowett Gisbert Richard R. J. Dwayne Miller 《PloS one》2015,10(3)
The impact of using a Femtosecond laser on final functional results of penetrating keratoplasty is low. The corneal incisions presented here result from laser ablations with ultrafast desorption by impulsive vibrational excitation (DIVE). The results of the current study are based on the first proof-of-principle experiments using a mobile, newly introduced picosecond infrared laser system, and indicate that wavelengths in the mid-infrared range centered at 3 μm are efficient for obtaining applanation-free deep cuts on porcine corneas. 相似文献
169.
Hans Jobst Rahmsdorf Helmut Ponta Margarete Bächle Udo Mallick Karl-Friedrich Weibezahn Peter Herrlich 《Experimental cell research》1981,136(1):111-117
Various isolated cells of an inbred mouse strain (BALB/c) differed widely in their sensitivity to gamma irradiation: fibroblasts are five times more resistant than peripheral lymphocytes. Among lymphocytes, T cells are more resistant than B cells. Cell lines derived from the primary cells conserved their radiosensitivity. Cytofluorometric measurements show that the differential reaction of a cell to gamma irradiation can be detected already 2–3 h after the irradiation event. Radiation-sensitive cells are delayed for a longer time in S phase and G2 phase of the cell cycle than radiation-resistant cells. No difference in the capacity of the cells to perform single-strand break repair, double-strand break repair or unscheduled DNA synthesis could yet be detected. 相似文献
170.