Studies of genetic correlations between traits that ostensibly channel the path of evolution away from the direction of natural selection require information on key aspects such as ancestral phenotypes, the duration of adaptive evolution, the direction of natural selection, and genetic covariances. In this study we provide such information in a frog population system. We studied adaptation in life history traits to pool drying in frog populations on islands of known age, which have been colonized from a mainland population. The island populations show strong local adaptation in development time and size. We found that the first eigenvector of the variance–covariance matrix (gmax) had changed between ancestral mainland populations and newly established island populations. Interestingly, there was no divergence in gmax among island populations that differed in their local adaptation in development time and size. Thus, a major change in the genetic covariance of life-history traits occurred in the colonization of the island system, but subsequent local adaptation in development time took place despite the constraints imposed by the genetic covariance structure. 相似文献
Replication origins were mapped in hyperthermophilic crenarchaea, using high‐throughput sequencing‐based marker frequency analysis. We confirm previous origin mapping in Sulfolobus acidocaldarius, and demonstrate that the single chromosome of Pyrobaculum calidifontis contains four replication origins, the highest number detected in a prokaryotic organism. The relative positions of the origins in both organisms coincided with regions enriched in highly conserved (core) archaeal genes. We show that core gene distribution provides a useful tool for origin identification in archaea, and predict multiple replication origins in a range of species. One of the P. calidifontis origins was mapped in detail, and electrophoretic mobility shift assays demonstrated binding of the Cdc6/Orc1 replication initiator protein to a repeated sequence element, denoted Orb‐1, within the origin. The high‐throughput sequencing approach also allowed for an annotation update of both genomes, resulting in the restoration of open reading frames encoding proteins involved in, e.g., sugar, nitrate and energy metabolism, as well as in glycosylation and DNA repair. 相似文献
Chemotherapy resistance is a major obstacle in effective neoadjuvant treatment for estrogen receptor-positive breast cancer. The ability to predict tumour response would allow chemotherapy administration to be directed towards only those patients who would benefit, thus maximising treatment efficiency. We aimed to identify putative protein biomarkers associated with chemotherapy resistance, using fresh tumour samples with antibody microarray analysis and then to perform pilot clinical validation experiments.
Materials and methods
Chemotherapy resistant and chemotherapy sensitive tumour samples were collected from breast cancer patients who had received anthracycline based neoadjuvant therapy consisting of epirubicin with cyclophosphamide followed by docetaxel. A total of 5 comparative proteomics experiments were performed using invasive ductal carcinomas which demonstrated estrogen receptor positivity (luminal subtype). Protein expression was compared between chemotherapy resistant and chemotherapy sensitive tumour samples using the Panorama XPRESS Profiler725 antibody microarray containing 725 antibodies from a wide variety of cell signalling and apoptosis pathways. A pilot series of archival samples was used for clinical validation of putative predictive biomarkers.
Results
AbMA analysis revealed 38 differentially expressed proteins which demonstrated at least 1.8 fold difference in expression in chemotherapy resistant tumours and 7 of these proteins (Zyxin, 14-3-3 theta/tau, tBID, Pinin, Bcl-xL, RIP and MyD88) were found in at least 2 experiments. Clinical validation in a pilot series of archival samples revealed 14-3-3 theta/tau and tBID to be significantly associated with chemotherapy resistance.
Conclusions
For the first time, antibody microarrays have been used to identify proteins associated with chemotherapy resistance using fresh breast cancer tissue. We propose a potential role for 14-3-3 theta/tau and tBID as predictive biomarkers of neoadjuvant chemotherapy resistance in breast cancer. Further validation in a larger sample series is now required. 相似文献
Neoadjuvant chemotherapy is used to treat oestrogen receptor-positive breast cancer however chemo-resistance is a major obstacle in this molecular subtype. The ability to predict tumour response would allow chemotherapy administration to be directed towards patients who would most benefit, thus maximising treatment efficacy. We aimed to identify protein biomarkers associated with response to neoadjuvant chemotherapy, in a pilot study using comparative 2-DE MALDI TOF/TOF MS proteomic analysis of breast tumour samples. A total of 3 comparative proteomic experiments were performed, comparing protein expression between chemotherapy-sensitive and chemotherapy-resistant oestrogen receptor-positive invasive ductal carcinoma tissue samples. This identified a list of 132 unique proteins that were significantly differentially expressed (≥ 2 fold) in chemotherapy resistant samples, 57 of which were identified in at least two experiments. Ingenuity? Pathway Analysis was used to map the 57 DEPs onto canonical signalling pathways. We implicate several isoforms of 14-3-3 family proteins (theta/tau, gamma, epsilon, beta/alpha and zeta/delta), which have previously been associated with chemotherapy resistance in breast cancer. Extensive clinical validation is now required to fully assess the role of these proteins as putative markers of chemotherapy response in luminal breast cancer subtypes. 相似文献
Our long-term goal is to develop a Swedish winter oat (Avena sativa). To identify molecular differences that correlate with winter hardiness, a winter oat model comprising of both non-hardy spring lines and winter hardy lines is needed. To achieve this, we selected 294 oat breeding lines, originating from various Russian, German, and American winter oat breeding programs and tested them in the field in south- and western Sweden. By assaying for winter survival and agricultural properties during four consecutive seasons, we identified 14 breeding lines of different origins that not only survived the winter but also were agronomically better than the rest. Laboratory tests including electrolytic leakage, controlled crown freezing assay, expression analysis of the AsVrn1 gene and monitoring of flowering time suggested that the American lines had the highest freezing tolerance, although the German lines performed better in the field. Finally, six lines constituting the two most freezing tolerant lines, two intermediate lines and two spring cultivars were chosen to build a winter oat model system. Metabolic profiling of non-acclimated and cold acclimated leaf tissue samples isolated from the six selected lines revealed differential expression patterns of 245 metabolites including several sugars, amino acids, organic acids and 181 hitherto unknown metabolites. The expression patterns of 107 metabolites showed significant interactions with either a cultivar or a time-point. Further identification, characterisation and validation of these metabolites will lead to an increased understanding of the cold acclimation process in oats. Furthermore, by using the winter oat model system, differential sequencing of crown mRNA populations would lead to identification of various biomarkers to facilitate winter oat breeding. 相似文献
To develop methods for studying phosphorylation of protein tyrosine residues is an important task since this protein modification regulates many cellular functions and often is involved in oncogenesis. An optimal protocol includes enrichment of tyrosine phosphorylated (pTyr) peptides or proteins, followed by a high resolving analytical method for identification of the enriched components. In this Methods paper, we describe a working strategy on how immunoaffinity enrichments, using anti-pTyr antibodies, combined with mass spectrometric (MS) analysis can be used to study the pTyr proteome. We describe in detail how our procedure was used to characterize the pTyr proteome of K562 leukemia cells. Important questions concerning the use of different anti-pTyr antibodies, enrichments performed at the peptide and/or the protein level, pooling of enrichments and requirements for the MS characterization are discussed. 相似文献
Abstract Insects protect themselves against microbial infection by an efficient innate immune system that is activated by recognition of invariant microbial surface molecules. In the fruit fly Drosophila melanogaster the presence of bacteria is associated with expression of antimicrobial peptides in host immune‐competent tissues. Host receptors detect infection and relay the signal to mount the appropriate immune response. In Drosophila hemocyte‐like l(2)mbn cells pre‐infection treatment with Pefabloc, a commonly used serine protease inhibitor, induced two major effects: it blocked expression of the antibacterial peptide Diptericin in response to live Gram‐negative bacteria and bacterial surface molecules (crude lipopolysaccharide contaminated by peptidoglycans) and it induced morphological changes. 相似文献
The aim of this study was to compare a gel-based test with the traditional direct agglutination test (DAT) for the diagnosis of immune-mediated haemolytic anaemia (IMHA).
Methods
Canine (n = 247) and feline (n = 74) blood samples were submitted for DAT testing to two laboratories. A subset of canine samples was categorized as having idiopathic IMHA, secondary IMHA, or no IMHA.
Results
The kappa values for agreement between the tests were in one laboratory 0.86 for canine and 0.58 for feline samples, and in the other 0.48 for canine samples. The lower agreement in the second laboratory was caused by a high number of positive canine DATs for which the gel test was negative. This group included significantly more dogs with secondary IMHA.
Conclusions
The gel test might be used as a screening test for idiopathic IMHA and is less often positive in secondary IMHA than the DAT. 相似文献
The aim of this study was to determine the effects of pelagic mysids (Mysis mixta and M. relicta) on the biomass and size-structure of the phytoplankton community during the period following the spring bloom. Mysids excreted phosphate (4.5 ± 0.7 nmol ind−1 h−1) and ammonium (123.6 ± 31.6 and 45.0 ± 3.2 nmol ind−1 h−1) and increased the total chlorophyll-a concentration of phytoplankton slightly. However, the presence of mysids affected different size-classes of phytoplankton differently. Mysids mainly grazed on large-sized (>10 μm) phytoplankton cells. Small-sized (<10 μm) algal cells avoided grazing, gained a competitive advantage and were able to utilize the nutrients excreted by mysids. According to this study, both top-down and bottom-up mechanisms simultaneously mould the structure of the phytoplankton community. A large zooplankton biomass might promote the increase of small flagellates by a combination of repleting nutrient stores, selective grazing on large algal cells and heavy predation on protozoa which, consequently, might have a cascading effect on the most favoured protozoan food source, small flagellates.