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41.
Sieghart Sopper Susanne Hemm Jürgen Meixensberger Cheik Coulibaly Christiane Stahl-Hennig Gerhard Hunsmann Bernhard Fleckenstein Volker ter Meulen Rüdiger Drries 《Journal of medical primatology》1993,22(2-3):138-146
Paired sera and CSF samples were collected from SIVmac-infected macaques. Animals infected with SIVmac251 maintained low gag and high env-specific antibody levels in plasma. Increasing env-specific antibody titers in CSF were associated in one animal with strong intrathecal synthesis. SIVmac239-infected monkeys revealed high antibody titers of gag and env-specificity, in one animal accompanied by weak intrathecal synthesis of virus-specific antibodies. In all animals, the CD4/CD8 ratio in CSF decreased faster compared to blood. 相似文献
42.
43.
Catherine Jumarie Christiane Malo 《In vitro cellular & developmental biology. Animal》1994,30(11):753-760
Summary Caco-2 cell human colon adenocarcinoma cell line was used to study the hormonal regulation of small intestinal epithelial
cell differentiation. We had previously shown that insulin-transferrin-selenium and triiodothyronine (5 × 10−8
M)-supplemented medium can best replace serum after 2 days of culture for both the maintenance and differentiation of Caco-2
cells. The present study demonstrates that precoating petri dishes with complete serum allows the growth and differentiation
of Caco-2 cells seeded directly in serum-free medium. On the other hand, precoating with dialyzed serum inhibits alkaline
phosphatase and dipeptidyl-dipeptidase IV activities by more than 50%. The results obtained with complete serum-precoated
culture plates indicate that there is no synergy between insulin and triiodothyronine because cells maintained in transferrin-selenium
and triiodothyronine-supplemented medium, with or without insulin, express comparable enzyme activities. Moreover, large increases
in alkaline phosphatase and dipeptidyl-dipeptidase IV activities were observed when triiodothyronine was added to the culture
medium by the time confluency was reached. In contrast, γ-glutamyltransferase was lowered to a greater extent when triiodothyronine
was present from the beginning of culture. These findings show that triiodothyronine preferentially stimulates alkaline phosphatase
and dipeptidyl-dipeptidase IV activities during the differentiation period whereas it selectively inhibits γ-glutamyltransferase
during the proliferation phase. Triiodothyronine acts in a dose-dependent manner. 相似文献
44.
Bernd-Ulrich Meyburg Wolfgang Scheller und Christiane Meyburg 《Journal of Ornithology》1993,134(2):173-179
Zusammenfassung 1992 konnte ein Schreiadler mit Hilfe der Satelliten-Telemetrie nach dem Abzug aus dem Brutgebiet in Mecklenburg-Vorpommern 2125 km weit verfolgt werden. Die Ortung erfolgte durch das AGROS-System. Der Abzug erfolgte am 16. oder 17. August in SE-Richtung. Nach 660 km Luftlinie in den polnisch-slowakischen West-Beskiden schwenkte der Vogel nach Süden ab und flog fast geradlinig zwischen dem 19 ° und 22 ° E weite auf dem kürzesten Weg in Richtung Nordafrika, bis er nach 1340 km am 29. September im äußersten Südwesten des Peloponnes eintraf. Dort zögerte er, seinen Zug fortzusetzen und flog mindestens 12 Tage in nördlicher und südlicher Richtung an der Westküste hin und her. Das plötzliche Ausbleiben von Signalen nach dem 8. Oktober bei bestem Ladezustand der Batterien wird dahingehend gedeutet, daß der Adler abgeschossen wurde oder bei dem Versuch, das Mittelmeer zu überqueren, umkam.
Satellite tracking of a juvenile Lesser Spotted Eagle (Aquila pomarina) during autumn migration
Summary In 1992, for the first time a Lesser Spotted Eagle was tracked with a satellite transmitter (PTT) for 2,125 km on its migration route from its birthplace in Mecklenburg-Vorpommern (Northern Germany). Locations were obtained by the ARGOS system. The migration began on 16 or 17 August in a south-easterly direction. After 660 km the young eagle veered south in the Beskidy mountains on the Polish-Slovak border (about 80 km south of Katowice) and flew in an almost straight line between 19 ° and 22 ° E on the shortest route to North Africa (not towards the Bosphorus) until after covering another 1,340 km it reached the extreme south-west of the Peloponnese (Greece) on 24 September. There it lingered for at least 12 days flying north and south, up and down the west coast before probably continuing on its migration. The abrupt cessation of signals after 8 October, notwithstanding the prime condition of the batteries, indicated that the eagle had been shot or perished in an attempt to cross the Mediterranean.相似文献
45.
Thomas Schiewe Björn Gutschmann Lara Santolin Saskia Waldburger Peter Neubauer Roland Hass Sebastian L. Riedel 《Biotechnology and bioengineering》2023,120(10):2880-2889
An efficient monitoring and control strategy is the basis for a reliable production process. Conventional optical density (OD) measurements involve superpositions of light absorption and scattering, and the results are only given in arbitrary units. In contrast, photon density wave (PDW) spectroscopy is a dilution-free method that allows independent quantification of both effects with defined units. For the first time, PDW spectroscopy was evaluated as a novel optical process analytical technology tool for real-time monitoring of biomass formation in Escherichia coli high-cell-density fed-batch cultivations. Inline PDW measurements were compared to a commercially available inline turbidity probe and with offline measurements of OD and cell dry weight (CDW). An accurate correlation of the reduced PDW scattering coefficient µs′ with CDW was observed in the range of 5–69 g L−1 (R2 = 0.98). The growth rates calculated based on µs′ were comparable to the rates determined with all reference methods. Furthermore, quantification of the reduced PDW scattering coefficient µs′ as a function of the absorption coefficient µa allowed direct detection of unintended process trends caused by overfeeding and subsequent acetate accumulation. Inline PDW spectroscopy can contribute to more robust bioprocess monitoring and consequently improved process performance. 相似文献
46.
Julia Schollmeyer Saskia Waldburger Kendra Njo Heba Yehia Anke Kurreck Peter Neubauer Sebastian L. Riedel 《Biotechnology and bioengineering》2023,120(11):3322-3334
Nucleoside phosphorylases are important biocatalysts for the chemo-enzymatic synthesis of nucleosides and their analogs which are, among others, used for the treatment of viral infections or cancer. S-methyl-5′-thioadenosine phosphorylases (MTAP) are a group of nucleoside phosphorylases and the thermostable MTAP of Aeropyrum pernix (ApMTAP) was described to accept a wide range of modified nucleosides as substrates. Therefore, it is an interesting biocatalyst for the synthesis of nucleoside analogs for industrial and therapeutic applications. To date, thermostable nucleoside phosphorylases were produced in shake flask cultivations using complex media. The drawback of this approach is low volumetric protein yields which hamper the wide-spread application of the thermostable nucleoside phosphorylases in large scale. High cell density (HCD) cultivations allow the production of recombinant proteins with high volumetric yields, as final optical densities >100 can be achieved. Therefore, in this study, we developed a suitable protocol for HCD cultivations of ApMTAP. Initially, optimum expression conditions were determined in 24-well plates using a fed-batch medium. Subsequently, HCD cultivations were performed using E. coli BL21-Gold cells, by employing a glucose-limited fed-batch strategy. Comparing different growth rates in stirred-tank bioreactors, cultivations revealed that growth at maximum growth rates until induction resulted in the highest yields of ApMTAP. On a 500-mL scale, final cell dry weights of 87.1–90.1 g L−1 were observed together with an overproduction of ApMTAP in a 1.9%–3.8% ratio of total protein. Compared to initially applied shake flask cultivations with terrific broth (TB) medium the volumetric yield increased by a factor of 136. After the purification of ApMTAP via heat treatment and affinity chromatography, a purity of more than 90% was determined. Activity testing revealed specific activities in the range of 0.21 ± 0.11 (low growth rate) to 3.99 ± 1.02 U mg−1 (growth at maximum growth rate). Hence, growth at maximum growth rate led to both an increased expression of the target protein and an increased specific enzyme activity. This study paves the way towards the application of thermostable nucleoside phosphorylases in industrial applications due to an improved heterologous expression in Escherichia coli. 相似文献
47.
48.
Thylakoid lamellae extend into the pyrenoids of only two genera of cryptomonad algae, Chroomonas and Hemiselmis, We used immunoelectron microscopy to assess the photosynthetic competency of cryptomonad intrapyrenoid thylakoids. Intrapyrenoid thylakoids possess phycobiliproteins and the chlorophyll a/c2 light-harvesting complex, both of which are associated with photosystem (PS) II in a light-harvesting capacity. In addition, thylakoids that extend into the pyrenoid of Hemiselmis brunnescens were immunolabelled by anti-PSI. These results indicate that cryptomonad intrapyrenoid thylakoids likely function in a manner analogous to thylakoids of the chloroplast stroma. Moreover, our observation that the Calvin cycle enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) is pyrenoid-localized in these two cryptophytes indicates that the processes of photosynthetic O2-evolution and ribulose 1,5-bisphosphate (RuBP) carboxylation/oxygenation are not spatially separated in these algae. 相似文献
49.
Sarrah M'Barek Ziad Fajloun Sandrine Cestle Christiane Devaux Pascal Mansuelle Amor Mosbah Besma Jouirou Massimo Mantegazza Jurphaas van Rietschoten Mohamed El Ayeb Herv Rochat Jean‐Marc Sabatier Francois Sampieri 《Journal of peptide science》2004,10(11):666-677
Aah I is a 63-residue alpha-toxin isolated from the venom of the Buthidae scorpion Androctonus australis hector, which is considered to be the most dangerous species. We report here the first chemical synthesis of Aah I by the solid-phase method, using a Fmoc strategy. The synthetic toxin I (sAah I) was renatured in DMSO-Tris buffer, purified and subjected to thorough analysis and comparison with the natural toxin. The sAah I showed physico-chemical (CD spectrum, molecular mass, HPLC elution), biochemical (amino-acid composition, sequence), immunochemical and pharmacological properties similar to those of the natural toxin. The synthetic toxin was recognized by a conformation-dependent monoclonal anti-Aah I antibody, with an IC50 value close to that for the natural toxin. Following intracerebroventricular injection, the synthetic and the natural toxins were similarly lethal to mice. In voltage-clamp experiments, Na(v) 1.2 sodium channel inactivation was inhibited by the application of sAah I or of the natural toxin in a similar way. This work describes a simple protocol for the chemical synthesis of a scorpion alpha-toxin, making it possible to produce structural analogues in time. 相似文献
50.
P. Haffter Jörg Odenthal M. C. Mullins Shuo Lin Michael J. Farrell E. Vogelsang F. Haas M. Brand Fredericus J. M. van Eeden Makoto Furutani-Seiki Michael Granato M. Hammerschmidt Carl-Philipp Heisenberg Yun-Jin Jiang D. A. Kane R. N. Kelsh Nancy Hopkins Christiane Nüsslein-Volhard 《Development genes and evolution》1996,206(4):260-276
Mutations causing a visible phenotype in the adult serve as valuable visible genetic markers in multicellular genetic model
organisms such as Drosophila melanogaster, Caenorhabditis elegans and Arabidopsis thaliana. In a large scale screen for mutations affecting early development of the zebrafish, we identified a number of mutations
that are homozygous viable or semiviable. Here we describe viable mutations which produce visible phenotypes in the adult
fish. These predominantly affect the fins and pigmentation, but also the eyes and body length of the adult. A number of dominant
mutations caused visible phenotypes in the adult fish. Mutations in three genes, long fin, another long fin and wanda affected fin formation in the adult. Four mutations were found to cause a dominant reduction of the overall body length in
the adult. The adult pigment pattern was found to be changed by dominant mutations in wanda, asterix, obelix, leopard, salz and pfeffer. Among the recessive mutations producing visible phenotypes in the homozygous adult, a group of mutations that failed to
produce melanin was assayed for tyrosinase activity. Mutations in sandy produced embryos that failed to express tyrosinase activity. These are potentially useful for using tyrosinase as a marker
for the generation of transgenic lines of zebrafish.
Received: 17 June 1996 / Accepted: 15 July 1996 相似文献