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61.
Steven H. Ferguson David J. Yurkowski Brent G. Young Cornelia Willing Xinhua Zhu Derek C. G. Muir Aaron T. Fisk Gregory W. Thiemann 《Population Ecology》2019,61(4):371-382
Mammals adapted to unpredictable and low-energy environments often evolve a “bet-hedging” life history strategy characterized by less costly reproductive outputs over a longer and slower-growing life. In contrast, species adapted to more predictable (i.e., low variation) and higher energy environments may evolve greater fecundity over a shorter and faster-growing life. We tested whether this known interspecific pattern also occurs within a species. We compared life history traits of the ringed seal (Pusa hispida) in the Canadian High Arctic to those closer to the southern limit of the species' circumpolar distribution. We found that northern seals grew slower than southern seals (Brody growth coefficient), achieved a greater asymptotic body weight (82 and 69 kg vs. 74 and 54 kg female and male, respectively), reached sexual maturity later (6.1 years vs. 4.5 years), had lower fecundity (1.8 years vs. 1.3 years interbirth interval), longer average lifespan (5 years vs. 3 years median age), and greater movements (1,269 vs. 681 km). Mating systems also likely differed with northern seals showing morphological evidence of a promiscuous mating system with potential sperm competition as indicated by greater relative testes size. The northern region was also characterized by more unpredictable environmental timing of seasonal events, such as spring sea ice breakup. Life history variation between the intraspecific groups of seals appears to agree with interspecific patterns and provides a better understanding of how species' life history parameters shift in concert with environmental conditions. 相似文献
62.
Cornelia Walther Martin Voigtmann Elena Bruna Ali Abusnina Anne-Luise Tscheließnig Michael Allmer Hermann Schuchnigg Cécile Brocard Alexandra Föttinger-Vacha Georg Klima 《Biotechnology progress》2022,38(3):e3249
The development of a biopharmaceutical production process usually occurs sequentially, and tedious optimization of each individual unit operation is very time-consuming. Here, the conditions established as optimal for one-step serve as input for the following step. Yet, this strategy does not consider potential interactions between a priori distant process steps and therefore cannot guarantee for optimal overall process performance. To overcome these limitations, we established a smart approach to develop and utilize integrated process models using machine learning techniques and genetic algorithms. We evaluated the application of the data-driven models to explore potential efficiency increases and compared them to a conventional development approach for one of our development products. First, we developed a data-driven integrated process model using gradient boosting machines and Gaussian processes as machine learning techniques and a genetic algorithm as recommendation engine for two downstream unit operations, namely solubilization and refolding. Through projection of the results into our large-scale facility, we predicted a twofold increase in productivity. Second, we extended the model to a three-step model by including the capture chromatography. Here, depending on the selected baseline-process chosen for comparison, we obtained between 50% and 100% increase in productivity. These data show the successful application of machine learning techniques and optimization algorithms for downstream process development. Finally, our results highlight the importance of considering integrated process models for the whole process chain, including all unit operations. 相似文献
63.
Thuswaldner S Lagerstedt JO Rojas-Stütz M Bouhidel K Der C Leborgne-Castel N Mishra A Marty F Schoefs B Adamska I Persson BL Spetea C 《The Journal of biological chemistry》2007,282(12):8848-8859
In plants the chloroplast thylakoid membrane is the site of light-dependent photosynthetic reactions coupled to ATP synthesis. The ability of the plant cell to build and alter this membrane system is essential for efficient photosynthesis. A nucleotide translocator homologous to the bovine mitochondrial ADP/ATP carrier (AAC) was previously found in spinach thylakoids. Here we have identified and characterized a thylakoid ATP/ADP carrier (TAAC) from Arabidopsis.(i) Sequence homology with the bovine AAC and the prediction of chloroplast transit peptides indicated a putative carrier encoded by the At5g01500 gene, as a TAAC. (ii) Transiently expressed TAAC-green fluorescent protein fusion construct was targeted to the chloroplast. Western blotting using a peptide-specific antibody together with immunogold electron microscopy revealed a major location of TAAC in the thylakoid membrane. Previous proteomic analyses identified this protein in chloroplast envelope preparations. (iii) Recombinant TAAC protein specifically imports ATP in exchange for ADP across the cytoplasmic membrane of Escherichia coli. Studies on isolated thylakoids from Arabidopsis confirmed these observations. (iv) The lack of TAAC in an Arabidopsis T-DNA insertion mutant caused a 30-40% reduction in the thylakoid ATP transport and metabolism. (v) TAAC is readily expressed in dark-grown Arabidopsis seedlings, and its level remains stable throughout the greening process. Its expression is highest in developing green tissues and in leaves undergoing senescence or abiotic stress. We propose that the TAAC protein supplies ATP for energy-dependent reactions during thylakoid biogenesis and turnover in plants. 相似文献
64.
Background
Feasibility of genotyping of hundreds and thousands of single nucleotide polymorphisms (SNPs) in thousands of study subjects have triggered the need for fast, powerful, and reliable methods for genome-wide association analysis. Here we consider a situation when study participants are genetically related (e.g. due to systematic sampling of families or because a study was performed in a genetically isolated population). Of the available methods that account for relatedness, the Measured Genotype (MG) approach is considered the ‘gold standard’. However, MG is not efficient with respect to time taken for the analysis of genome-wide data. In this context we proposed a fast two-step method called Genome-wide Association using Mixed Model and Regression (GRAMMAR) for the analysis of pedigree-based quantitative traits. This method certainly overcomes the drawback of time limitation of the measured genotype (MG) approach, but pays in power. One of the major drawbacks of both MG and GRAMMAR, is that they crucially depend on the availability of complete and correct pedigree data, which is rarely available.Methodology
In this study we first explore type 1 error and relative power of MG, GRAMMAR, and Genomic Control (GC) approaches for genetic association analysis. Secondly, we propose an extension to GRAMMAR i.e. GRAMMAR-GC. Finally, we propose application of GRAMMAR-GC using the kinship matrix estimated through genomic marker data, instead of (possibly missing and/or incorrect) genealogy.Conclusion
Through simulations we show that MG approach maintains high power across a range of heritabilities and possible pedigree structures, and always outperforms other contemporary methods. We also show that the power of our proposed GRAMMAR-GC approaches to that of the ‘gold standard’ MG for all models and pedigrees studied. We show that this method is both feasible and powerful and has correct type 1 error in the context of genome-wide association analysis in related individuals. 相似文献65.
Schymeinsky J Then C Sindrilaru A Gerstl R Jakus Z Tybulewicz VL Scharffetter-Kochanek K Walzog B 《PloS one》2007,2(11):e1132
The non-receptor tyrosine kinase Syk is mainly expressed in the hematopoietic system and plays an essential role in beta(2) integrin-mediated leukocyte activation. To elucidate the signaling pathway downstream of Syk during beta2 integrin (CD11/CD18)-mediated migration and extravasation of polymorphonuclear neutrophils (PMN), we generated neutrophil-like differentiated HL-60 (dHL-60) cells expressing a fluorescently tagged Syk mutant lacking the tyrosine residue at the position 323 (Syk-Tyr323) that is known to be required for the binding of the regulatory subunit p85 of the phosphatidylinositol 3-kinase (PI3K) class I(A). Syk-Tyr323 was found to be critical for the enrichment of the catalytic subunit p110delta of PI3K class I(A) as well as for the generation of PI3K products at the leading edge of the majority of polarized cells. In accordance, the translocation of PI3K p110delta to the leading edge was diminished in Syk deficient murine PMN. Moreover, the expression of EGFP-Syk Y323F interfered with proper cell polarization and it impaired efficient migration of dHL-60 cells. In agreement with a major role of beta2 integrins in the recruitment of phagocytic cells to sites of lesion, mice with a Syk-deficient hematopoietic system demonstrated impaired PMN infiltration into the wounded tissue that was associated with prolonged cutaneous wound healing. These data imply a novel role of Syk via PI3K p110delta signaling for beta2 integrin-mediated migration which is a prerequisite for efficient PMN recruitment in vivo. 相似文献
66.
Fina A. S Kurreeman Leonid Padyukov Rute B Marques Steven J Schrodi Maria Seddighzadeh Gerrie Stoeken-Rijsbergen Annette H. M van der Helm-van Mil Cornelia F Allaart Willem Verduyn Jeanine Houwing-Duistermaat Lars Alfredsson Ann B Begovich Lars Klareskog Tom W. J Huizinga Rene E. M Toes 《PLoS medicine》2007,4(12)
67.
Koen A. J. Pelsma Michiel H. in 't Zandt Huub J. M. Op den Camp Mike S. M. Jetten Joshua F. Dean Cornelia U. Welte 《Environmental microbiology》2022,24(1):82-97
Urbanised environments have been identified as hotspots of anthropogenic methane emissions. Especially urban aquatic ecosystems are increasingly recognised as important sources of methane. However, the microbiology behind these emissions remains unexplored. Here, we applied microcosm incubations and molecular analyses to investigate the methane-cycling community of the Amsterdam canal system in the Netherlands. The sediment methanogenic communities were dominated by Methanoregulaceae and Methanosaetaceae, with co-occurring methanotrophic Methanoperedenaceae and Methylomirabilaceae indicating the potential for anaerobic methane oxidation. Methane was readily produced after substrate amendment, suggesting an active but substrate-limited methanogenic community. Bacterial 16S rRNA gene amplicon sequencing of the sediment revealed a high relative abundance of Thermodesulfovibrionia. Canal wall biofilms showed the highest initial methanotrophic potential under oxic conditions compared to the sediment. During prolonged incubations the maximum methanotrophic rate increased to 8.08 mmol gDW−1 d−1 that was concomitant with an enrichment of Methylomonadaceae bacteria. Metagenomic analysis of the canal wall biofilm lead to the recovery of a single methanotroph metagenome-assembled genome. Taxonomic analysis showed that this methanotroph belongs to the genus Methyloglobulus. Our results underline the importance of previously unidentified and specialised environmental niches at the nexus of the natural and human-impacted carbon cycle. 相似文献
68.
Maria Isabel Perez-Lopez Rudy Mendez-Reina Steve Trier Cornelia Herrfurth Ivo Feussner Adriana Bernal Manu Forero-Shelton Chad Leidy 《生物化学与生物物理学报:生物膜》2019,1861(5):978-987
Bacteria are often found in close association with surfaces, resulting in the formation of biofilms. In Staphylococcus aureus (S. aureus), biofilms are implicated in the resilience of chronic infections, presenting a serious clinical problem world-wide. Here, S. aureus biofilms are grown under flow within clinical catheters at 37 °C. The lipid composition and biophysical properties of lipid extracts from these biofilms are compared with those from exponential growth and stationary phase cells. Biofilms show a reduction in iso and anteiso branching compensated by an increase in saturated fatty acids compared to stationary phase. A drastic reduction in carotenoid levels is also observed during biofilm formation. Thermotropic measurements of Laurdan GP and DPH polarization, show a reduction of lipid packing at 37 °C for biofilms compared to stationary phase. We studied the effects of carotenoid content on DMPG and DPPG model membranes showing trends in thermotropic behavior consistent with those observed in bacterial isolates, indicating that carotenoids participate in modulating lipid packing. Additionally, bending elastic constant (kc) measurements using vesicle fluctuation analysis (VFA) show that the presence of carotenoids can increase membrane bending rigidity. The antimicrobial peptide Magainin H2 was less activity on liposomes composed of stationary phase compared to biofilms or exponential growth isolates. This study contributes to an understanding of how Staphylococcus aureus modulates the composition of its membrane lipids, and how those changes affect the biophysical properties of membranes, which in turn may play a role in its virulence and its resistance to different membrane-active antimicrobial agents. 相似文献
69.
Janina Burk Heidrun Holland Anne F. Lauermann Tobias May Philipp Siedlaczek Verena Charwat Cornelia Kasper 《Biotechnology and bioengineering》2019,116(6):1417-1426
Multipotent mesenchymal stromal cells (MSC) and MSC-derived products have emerged as promising therapeutic tools. To fully exploit their potential, further mechanistic studies are still necessary and bioprocessing needs to be optimized, which requires an abundant supply of functional MSC for basic research. To address this need, here we used a novel technology to establish a human adipose-derived MSC line with functional characteristics representative of primary MSC. Primary MSC were isolated and subjected to lentiviral transduction with a library of expansion genes. Clonal cell lines were generated and evaluated on the basis of their morphology, immunophenotype, and proliferation potential. One clone (K5 iMSC) was then selected for further characterization. This clone had integrated a specific transgene combination including genes involved in stemness and maintenance of adult stem cells. Favorably, the K5 iMSC showed cell characteristics resembling juvenile MSC, as they displayed a shorter cell length and enhanced migration and proliferation compared with the non-immortalized original primary MSC (p < 0.05). Still, their immunophenotype and differentiation potential corresponded to the original primary MSC and the MSC definition criteria, and cytogenetic analyses revealed no clonal aberrations. We conclude that the technology used is applicable to generate functional MSC lines for basic research and possible future bioprocessing applications. 相似文献
70.
Neuronal cell fates are specified by a hierarchy of events mediated by cell-intrinsic determinants and cell-cell interactions. The determination of cell fate can be subdivided into three general steps. First, cell fate is restricted by the cell's position in the animal. For example, neurons are specified along the anterior-posterior body axis through the action of the Hox genes lin-39, mab-5, and egl-5. Second, a decision is made to generate a particular cell type, such as the progenitor of a neurogenic lineage as opposed to that of an epidermal lineage. Among the genes that influence this decision is the proneural gene lin-32. Third, characteristics of a particular cell type are specified. For example, in a neurogenic lineage, a decision may be made to generate a specific neuron type such as a sensory or motor neuron. Genes that affect neuronal fate can act in different ways to influence the development of different types of neurons. © 1996 Wiley-Liss, Inc. 相似文献