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Summary A stochastic measure of genetic distance between populations is proposed; unlike currently used measures, it is invariant with respect to union and subdivision of loci. This measure enables a unified quantitative approach to genetic diversity within populations and genetic distance between populations. 相似文献
894.
Lars S. Nielsen Alexandra Baer Christian Müller Kristian Gregersen Nina T. Mønster Søren K. Rasmussen Dietmar Weilguny Anne B. Tolstrup 《Molecular biotechnology》2010,45(3):257-266
We have previously described the development and implementation of a strategy for production of recombinant polyclonal antibodies
(rpAb) in single batches employing CHO cells generated by site-specific integration, the SympressTM I technology. The SympressTM I technology is implemented at industrial scale, supporting a phase II clinical development program. Production of recombinant
proteins by site-specific integration, which is based on incorporation of a single copy of the gene of interest, makes the
SympressTM I technology best suited to support niche indications. To improve titers while maintaining a cost-efficient, highly reproducible
single-batch manufacturing mode, we have evaluated a number of different approaches. The most successful results were obtained
using random integration in a new producer cell termed ECHO, a CHO DG44 cell derivative engineered for improved productivity
at Symphogen. This new expression process is termed the SympressTM II technology. Here we describe proof-of-principle data demonstrating the feasibility of the SympressTM II technology for single-batch rpAb manufacturing using two model systems each composed of six target-specific antibodies.
The compositional stability and the batch-to-batch reproducibility of rpAb produced by the ECHO cells were at least as good
as observed previously using site-specific integration technology. Furthermore, the new process had a significant titer increase. 相似文献
895.
Calcium limitation in Daphnia magna 总被引:1,自引:0,他引:1
The role of ambient calcium concentrations on survival, moulting,growth and egg production was assessed in the cladoceran Daphniamagna. A threshold for survival was found in the range 0.10.5mg Ca l1, even when ionic strength of the medium waskept constant. Accumulated length and length specific dry weightwas retarded at low Ca (0.51.0 mg Ca l1) at foodconcentrations above incipient limiting level. For lower foodlevels, the effect of Ca on growth was less clear. The effectof low Ca on growth rate was most manifest during the firstdays after hatching, reflecting the higher Ca demands of theearly juveniles. Age-specific egg production was strongly reducedat Ca concentrations <10 mg Ca l1. This was partlyan indirect effect of reduced growth rates, but could also bean effect of higher energetic costs associated with Ca uptakein a Ca-poor medium. The high Ca demands in D.magna may notbe representative of other Daphnia species. Nevertheless, highspecific Ca content seems to be a common property of Daphniaspp. and Ca deficiency could be a major determinant of speciessuccess and community structure among crustacean zooplankton;it also puts constraints on carbon sequestration in the pelagicfood web of softwater lakes. 相似文献
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1. The actions of the calcium channel blocker verapamil were studied at the neuromuscular junction of the frog Rana pipiens. 2. In the presence of 50 microM verapamil, subthreshold endplate potentials were produced, and the quantal content was reduced by a factor of 3. 3. Verapamil (10-50 microM) also reduced the postjunctional membrane sensitivity as measured by (a) carbachol iontophoresis and (b) miniature endplate potential amplitude. In addition, verapamil had a strong inhibitory effect on the postjunctional membrane response to repetitive iontophoretic application of carbachol. 4. Thus, verapamil has both pre- and postsynaptic actions at the neuromuscular junction. 相似文献
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Anne L. Jaquiery Mark H. Oliver Nina Landon-Lane Samuel J. Matthews Jane E. Harding Frank H. Bloomfield 《PloS one》2013,8(4)
Irregular eating is associated with insulin resistance and metabolic disease in adults but may affect young, growing children differently. We investigated the metabolic effects of unpredictable feeding in female juvenile lambs randomly assigned to receive, for six weeks, maintenance feed given twice daily in equal portions (Control Group, C; n = 24) or the same weekly feed amount in aliquots of variable size at unpredictable times (Unpredictable Group, U; n = 21). Intravenous glucose tolerance tests (IVGTT), insulin tolerance tests (ITT), and measurement of diurnal plasma cortisol concentrations were performed pre and post the dietary intervention. Groups were compared using t test and RM ANOVA. Weight gain was similar in both groups (C 18±2%; U 16±2% of initial body weight). Glucose area under the curve (AUC) was unchanged in C (AUC pre 818±34, post 801±33 mmol.min.l−1), but increased by 20% in U (pre 830±25, post 1010±19 mmol.min.l−1; p<0.0001), with an inadequate insulin response to glucose load (log(AUC insulin first 40 minutes) post intervention C 1.49±0.04 vs U 1.36±0.04 ng.min.ml−1; p = 0.03). Insulin tolerance and diurnal variation of plasma cortisol concentrations were not different between groups. Unpredictable feeding impairs insulin response to glucose in growing lambs despite high quality food and normal weight gain. Irregular eating warrants investigation as a potentially remediable risk factor for disordered glucose metabolism. 相似文献
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