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121.
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123.
Existence of autocrine growth factors (aGFs) may influence the serum requirement for growth of hybridoma cells and thus significantly influence process economics. For the murine hybridoma cell line S3H5/2bA2, critical inoculum density (cID) and serum requirement for growth were inversely related for cultivation in both T flasks and spinner flasks. In spinner flasks, an inoculum density of 106 cells/ml was necessary for the cells to grow in RPMI 1640 medium without serum supplement, and an inoculum density of 103 cell/ml was necessary in RPMI 1640 medium with 10% serum. In T flasks, where the local cell density is higher than in spinner flasks, an inoculum density of 106 cells/ml was necessary for the cells to grow in RPMI 1640 medium without serum supplement, and an inoculum density of 1 cell/ml was also necessary in RPMI 1640 medium with 10% serum. Further, immobilized cells at high local cell density could grow under conditions where cells in T flasks at corresponding overall cell density could not grow. The cells at high inoculum density were less sensitive to shear induced by mechanical agitation than the cells at low inoculum density. Taken together these observations support the existence of secreted aGF(s) by the hybridoma cell line used. Since the specific MAb production rate was independent of cultivation method and inoculum density, the existence of autocrine growth factors would suggest that the use of immobilized cells should improve the economics of MAb production. 相似文献
124.
The possibility that weak, ac and dc magnetic fields in combination may affect binding equilibria of calcium-ions (Ca2+) was investigated with two metallochromic dyes as calcium-binding molecules: murexide and arsenazo III. Calcium-dye equilibria were followed by measuring solution absorbances with a fiber-optic spectrophotometer. A Ca(2+)-arsenazo solution was also used indirectly to monitor the binding of Ca2+ to calmodulin. Parallel, ac and dc magnetic fields were applied to each preparation. The ac magnetic field was held constant during each of a series of experiments at a frequency in the range between 50 and 120 Hz (sine wave) or at 50 pps (square wave) and at an rms flux density in the range between 65 and 156 microT. The dc magnetic field was then varied from 0 to 299 microT at 1.3 microT increments. The magnetic fields did not measurably affect equilibria in the binding of metallochromic dyes or calmodulin to Ca2+. 相似文献
125.
Novel tool in rheumatoid arthritis diagnosis—The usage of urease flap region peptidomimetics 下载免费PDF全文
Iwona Konieczna Inga Relich Maciej Durajski Lukasz Lechowicz Magdalena Chrapek Jozef Gaweda Justyna Fraczyk Zbigniew J. Kaminski 《Journal of peptide science》2018,24(6)
Rheumatoid arthritis (RA) is an autoimmune inflammatory disease. Early diagnosis can prevent joint erosion. However, available biomarkers do not always allow for clear distinction between RA and non‐RA individuals. It has become known that bacteria/viruses are among the environmental triggers that initiate RA via multiple molecular mechanisms. Thus, to better understand the role of bacteria in RA, we synthetized 6 peptidomimetics of bacterial ureases' flap region. These peptides were then used to distinguish RA patients from healthy people sera by immunoblotting. Most patients' sera were bound to peptidomimetic characteristic for Enterobacter sp. and Klebsiella sp. flap urease. We also found similarities between peptidomimetic sequence and human proteins connected with RA. This pilot study suggests that bacteria may trigger RA via mechanism of molecular mimicry of urease to host proteins and ureases flap peptidomimetics may be potential candidate as a new additional diagnostic test. 相似文献
126.
Nassif A Longo WE Sexe R Stratton M Standeven J Vernava AM Kaminski DL 《Mediators of inflammation》1995,4(6):452-453
We investigated whether Clostridium difficile toxin alters colonic tissue levels of vasoactive intestinal peptide (VIP) at the expense of changes in colonic motility in the isolated perfused rabbit left colon. Colonic inflammation was induced by the intracolonic administration of 10(-8) M C. difflcile toxin. Strain gauge transducers were sewn onto the serosal surface of the colon to evaluate colonic motility. C. difflcile administration produced histologic changes consistent with epithelial damage. This was associated with an increased production of prostaglandin E(2) and thromboxane B(2). Tissue levels of VIP but not substance P were significantly reduced. This was associated with an increased number of contractions per minute and an average force of each colonic contraction. These results suggest that tissue levels of VIP are suppressed by C. difflcile and may participate in colonic dysmotility during active inflammation. 相似文献
127.
John R. Evans Michael A. Kaminski Thomas M. Cronin Dieter K. Fütterer 《Marine Micropaleontology》1995,26(1-4)
Noncalcareous Pleistocene sediments of the Central Arctic Ocean contain sparse benthic foraminiferal assemblages consisting entirely of agglutinated taxa. Deep water agglutinated foraminifera are studied from two piston cores collected from the Lomonosov Ridge and Amundsen Basin [Cores PS 2177-5 (KAL) and 2176-3 (KAL)]. Core PS 2177-5 (KAL) contains an assemblage of 10 species, dominated by Cyclammina pusilla Brady, and is interpreted to reflect a bathyal environment with variable organic flux and nutrition levels. Core PS 2176-3 (KAL) in the Amundsen Basin yielded a very depauperate benthic foraminiferal assemblage. It is assumed that the environment was inhospitable for agglutinated foraminifera. 相似文献
128.
Unique features of internal initiation of hepatitis C virus RNA translation. 总被引:33,自引:1,他引:32 下载免费PDF全文
J E Reynolds A Kaminski H J Kettinen K Grace B E Clarke A R Carroll D J Rowlands R J Jackson 《The EMBO journal》1995,14(23):6010-6020
The question of whether hepatitis C virus (HCV) RNA is translated by a mechanism of internal ribosome entry has been examined by testing whether insertion of HCV sequences between the two cistrons of a dicistronic mRNA promotes translation of the downstream cistron in rabbit reticulocyte lysates. Deletion analysis showed that efficient internal initiation required a segment of the HCV genome extending from about nucleotides 40-370 and that deletions from the 3'-end of this element were highly deleterious. As the authentic initiation codon for HCV polyprotein synthesis is at nucleotide 342, this demonstrates that, besides 5'-UTR sequences, a short length of HCV coding sequences is required for internal initiation. This finding was confirmed in transfection assays of BT7-H cells and was shown to be independent of the nature of the downstream reporter cistron. The strong requirement for coding sequences is in sharp contrast to internal initiation of picornavirus RNA translation. As a probable correlate with this, it was also found that the efficiency of internal initiation was only marginally compromised when the authentic initiation codon was mutated to a non-AUG codon, again in sharp contrast with the picornaviruses. The finding that coding sequences are required for internal initiation has important implications for the design of experiments to test for internal initiation of translation of cellular mRNAs. 相似文献
129.
Macroalgal mass development in the Wadden Sea: First experiences with a monitoring system 总被引:2,自引:2,他引:0
K. Kolbe E. Kaminski H. Michaelis B. Obert J. Rahmel 《Helgoland Marine Research》1995,49(1-4):519-528
The distribution and cover density of macroalgae (Chlorophyta, Ulvaceae) were estimated by means of aerial surveys in 1990–1992
in the Wadden Sea of Niedersachsen, an intertidal area of some 1200 km2 situated at the German North Sea coast. Each year, up to a maximum of 15% of the total area was covered by algae. The spatial
distribution was heterogeneous. In some subregions the macroalgal carpets covered from 30% up to 60% of the tidal flats. The
cover density was at its peak in 1990. Additionally, tentative ground truth investigations were carried out on species composition.
Reviewing other reports of macroalgal mass development at various sites in Europe, it is assumed that in the German Wadden
Sea the recent macroalgal blooms have to be regarded as a response to eutrophication, and will presumably remain a chronic
problem for many years to come. 相似文献
130.
PbsP,a cell wall‐anchored protein that binds plasminogen to promote hematogenous dissemination of group B Streptococcus 下载免费PDF全文
Marco Buscetta Arnaud Firon Giampiero Pietrocola Carmelo Biondo Giuseppe Mancuso Angelina Midiri Letizia Romeo Roberta Galbo Mario Venza Isabella Venza Pierre‐Alexandre Kaminski Myriam Gominet Giuseppe Teti Pietro Speziale Patrick Trieu‐Cuot Concetta Beninati 《Molecular microbiology》2016,101(1):27-41
Streptococcus agalactiae (Group B Streptococcus or GBS) is a leading cause of invasive infections in neonates whose virulence is dependent on its ability to interact with cells and host components. We here characterized a surface protein with a critical function in GBS pathophysiology. This adhesin, designated PbsP, possesses two Streptococcal Surface Repeat domains, a methionine and lysine‐rich region, and a LPXTG cell wall‐anchoring motif. PbsP mediates plasminogen (Plg) binding both in vitro and in vivo and we showed that cell surface‐bound Plg can be activated into plasmin by tissue plasminogen activator to increase the bacterial extracellular proteolytic activity. Absence of PbsP results in a decreased bacterial transmigration across brain endothelial cells and impaired virulence in a murine model of infection. PbsP is conserved among the main GBS lineages and is a major plasminogen adhesin in non‐CC17 GBS strains. Importantly, immunization of mice with recombinant PbsP confers protective immunity. Our results indicate that GBS have evolved different strategies to recruit Plg which indicates that the ability to acquire cell surface proteolytic activity is essential for the invasiveness of this bacterium. 相似文献