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41.
42.
Comparative studies on the food of the black cormorant Phalacrocorax carbo and the harbour seal Phoca vitulina were carried out in two contrasting habitat types. Both species feed predominantly on bottom-dwelling fish. Black cormorants are able to utilize fish found both on vegetation-covered and naked sea beds at a water depth of less than 10 m, while harbour seals feed mainly on soft sea bottoms above 30 m where vegetation is scarce or lacking. The food overlap of the two piscivores is large in environments where large shallow sea bottoms are available, and small in areas where sea bottoms of soft material is found at greater depth. In areas where the shallow bottoms are covered by vegetation only, cormorants are able to feed on the fish species inhabiting this kind of environment. There is no evidence that these predators make a choice regarding prey species. 相似文献
43.
Tuomas Kaprio Tero Satomaa Annamari Heiskanen Cornelis H. Hokke André M. Deelder Harri Mustonen Jaana Hagstr?m Olli Carpen Juhani Saarinen Caj Haglund 《Molecular & cellular proteomics : MCP》2015,14(2):277-288
All human cells are covered by glycans, the carbohydrate units of glycoproteins, glycolipids, and proteoglycans. Most glycans are localized to cell surfaces and participate in events essential for cell viability and function. Glycosylation evolves during carcinogenesis, and therefore carcinoma-related glycan structures are potential cancer biomarkers. Colorectal cancer is one of the world''s three most common cancers, and its incidence is rising. Novel biomarkers are essential to identify patients for targeted and individualized therapy. We compared the N-glycan profiles of five rectal adenomas and 18 rectal carcinomas of different stages by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry. Paraffin-embedded tumor samples were deparaffinized, and glycans were enzymatically released and purified. We found differences in glycosylation between adenomas and carcinomas: monoantennary, sialylated, pauci-mannose, and small high-mannose N-glycan structures were more common in carcinomas than in adenomas. We also found differences between stage I–II and stage III carcinomas. Based on these findings, we selected two glycan structures: pauci-mannose and sialyl Lewis a, for immunohistochemical analysis of their tissue expression in 220 colorectal cancer patients. In colorectal cancer, poor prognosis correlated with elevated expression of sialyl Lewis a, and in advanced colorectal cancer, poor prognosis correlated with elevated expression of pauci-mannose. In conclusion, by mass spectrometry we found several carcinoma related glycans, and we demonstrate a method of transforming these results into immunohistochemistry, a readily applicable method to study biomarker expression in patient samples.Glycans, the carbohydrate units of glycoproteins, glycolipids, and proteoglycans, that cover all human cells. Around 1% of the human genome participates in the biosynthesis of glycans(1). This biosynthesis is the most complex post-translational modification of proteins, and the great variability in glycan structures contains a tremendous ability to fine-tune the chemical and biological properties of glycoproteins. The glycosylation process occurs most abundantly in the Golgi apparatus and the endoplasmic reticulum, but also occurs in the cytoplasm and nucleus (2). Most glycoconjugates are localized to cell surfaces, where glycans participate in events essential for cell viability and function, such as cell adhesion, motility, and intracellular signaling (2). Changes in these functions are key steps seen when normal cells transform to malignant ones, and these are also reflected in changes of a cell''s glycan profile, observed in many cancers (3, 4). Specific structural changes in glycans may serve as cancer biomarkers (5, 6), and changes in glycosylation profiles are related to aggressive behavior in tumor cells (7–9).Cancer-associated asparagine-linked glycan (N-glycan) structures may play specific roles in supporting tumor progression; growth (10, 11), invasion (12, 13), and angiogenesis (14). Changes in the N-glycan profile emerge in numerous cancers, including lung (15, 16), breast (17), and colorectal cancer (CRC)1 (16, 18). Balog et al. (18) comparing the N-glycomic profile of CRC tissue to adjacent normal mucosa, reported differences in specific glycan structures. Moreover, serum N-glycosylation profile from patients with CRC differ from those of healthy controls (19).Colorectal cancer is the third most common cause of cancer-related death worldwide and its incidence is rising; 40% of CRCs are of rectal origin. Roughly 40% of patients have localized disease (stage I–II; Dukes A–B), another 40% loco regional disease (stage III; Dukes C), and 20% metastasized disease (stage IV; Dukes D) (20). Although stage at diagnosis is the most important factor determining prognosis, clinical outcome, and response to adjuvant treatment can markedly vary within each stage. Adjuvant therapy routinely goes to stage III patients, but the benefit of adjuvant treatment for stage II patients is unclear. Of stage II patients, 80% are cured by radical surgery alone. To identify patients who will benefit from postoperative treatment, we need novel biomarkers. The glycan profile of the tumor tissue could provide new biomarkers for diagnosis and prognosis of cancer.In this study, we characterized the N-glycomic profiles of rectal adenomas and carcinomas by MALDI-TOF mass spectrometric (MS) profiling of asparagine-linked glycans. Our aim was to identify differences between adenomas and carcinomas, and also between cancers of different stages. Based on glycan profiling, we also chose, for immunohistochemical expression studies of a series of 220 CRC patients, two glycan markers: sialyl Lewis a and pauci-mannose. 相似文献
44.
Ash Bahl Patrick Barton Keith Bowers Moya V. Caffrey Rebecca Denton Peter Gilmour Shaun Hawley Tero Linannen Christopher A. Luckhurst Tobias Mochel Matthew W.D. Perry Robert J. Riley Emma Roe Brian Springthorpe Linda Stein Peter Webborn 《Bioorganic & medicinal chemistry letters》2012,22(21):6694-6699
The discovery and optimisation of a series of zwitterionic CCR3 antagonists is described. Optimisation of the structure led to AZ12436092, a compound with excellent selectivity over activity at hERG and outstanding pharmacokinetics in preclinical species. 相似文献
45.
Liisa Huttunen Pekka Niemelä Vladimir Ossipov Matti Rousi Tero Klemola 《Trees - Structure and Function》2012,26(3):809-819
Subarctic mountain birch (Betula pubescens ssp. czerepanovii) forests in northern Fennoscandia have shown a slight recovery from recent severe defoliation by the winter moth (Operophtera brumata). This development in trees is hypothesized to be a result of ameliorated growing conditions through increased summer temperatures.
We examined if accumulated thermal sum affects the ability of mountain birches to tolerate foliage losses. We quantified the
number of leaf-bearing short shoots, the emergence of inflorescences and the seasonal height growth of long shoots in both
intact and defoliated trees. We also determined the concentrations of carbon and nitrogen in leaves and carbohydrates in roots.
Our results show that defoliation constrained the growth of long shoots, as well as the emergence of inflorescences regardless
of thermal sum accumulation. However, the number of leaf-bearing short shoots did not differ between intact and defoliated
trees. In the both tree groups, the amounts of emerging leaves increased as a response to thermal sum accumulation. Also the
leaf carbon concentration increased in defoliated trees at higher thermal sums, whereas it decreased in intact controls. Generally,
the mean carbohydrate concentrations were greater in roots of defoliated than intact trees. However, with increased thermal
sums, root carbohydrates increased in intact trees but remained the same in defoliated trees. We conclude that thermal sum
accumulation does not greatly promote the recovery of mountain birches. Although the damaged trees produced more leaves at
warmer growing sites, this did not increase their height growth or carbohydrate gain in roots. 相似文献
46.
Kit M. Kovacs Alex Aguilar David Aurioles Vladimir Burkanov Claudio Campagna Nick Gales Tom Gelatt Simon D. Goldsworthy Simon J. Goodman Greg J. G. Hofmeyr Tero Härkönen Lloyd Lowry Christian Lydersen Jan Schipper Tero Sipilä Colin Southwell Simon Stuart Dave Thompson Fritz Trillmich 《Marine Mammal Science》2012,28(2):414-436
47.
Glycomics of bone marrow-derived mesenchymal stem cells can be used to evaluate their cellular differentiation stage 总被引:1,自引:0,他引:1
Annamari Heiskanen Tia Hirvonen Hanna Salo Ulla Impola Anne Olonen Anita Laitinen Sari Tiitinen Suvi Natunen Olli Aitio Halina Miller-Podraza Manfred Wuhrer André M. Deelder Jari Natunen Jarmo Laine Petri Lehenkari Juhani Saarinen Tero Satomaa Leena Valmu 《Glycoconjugate journal》2009,26(3):367-384
Human mesenchymal stem cells (MSCs) are adult multipotent progenitor cells. They hold an enormous therapeutic potential, but
at the moment there is little information on the properties of MSCs, including their surface structures. In the present study,
we analyzed the mesenchymal stem cell glycome by using mass spectrometric profiling as well as a panel of glycan binding proteins.
Structural verifications were obtained by nuclear magnetic resonance spectroscopy, mass spectrometric fragmentation, and glycosidase
digestions. The MSC glycome was compared to the glycome of corresponding osteogenically differentiated cells. More than one
hundred glycan signals were detected in mesenchymal stem cells and osteoblasts differentiated from them. The glycan profiles
of MSCs and osteoblasts were consistently different in biological replicates, indicating that stem cells and osteoblasts have
characteristic glycosylation features. Glycosylation features associated with MSCs rather than differentiated cells included
high-mannose type N-glycans, linear poly-N-acetyllactosamine chains and α2-3-sialylation. Mesenchymal stem cells expressed SSEA-4 and sialyl Lewis x epitopes. Characteristic
glycosylation features that appeared in differentiated osteoblasts included abundant sulfate ester modifications. The results
show that glycosylation analysis can be used to evaluate MSC differentiation state. 相似文献
48.
Jääskeläinen A Soukka T Lamminmäki U Korpimäki T Virta M 《Biotechnology and bioengineering》2009,102(4):1012-1024
Recently, we presented a simple method for generating biological functional protein-based nanoparticles that are ready for use as label agents in bioaffinity assays (J??skel?inen et al., 2007 Small 3:1362-1367). In this process, the particle shell (ferritin protein) and binding molecules are conjugated via genetic fusion, and particles with binding capacity are produced in a single bacterial cultivation. Production is combined with simple, non-chromatographic purification during which Europium ions are introduced into particles to serve as marker agents. Denaturation-refolding has previously performed by means of pH changes. Here, we test urea as an alternative agent for denaturation, and examine techniques to improve refolding of the functional particles. Three different types of binding molecules were employed in our experiments: biotin carboxyl carrier protein (a small protein with 87 amino acids), single chain antibody fragment (a complex binding protein) and calmodulin-binding peptide (27 amino acids). Urea was successfully utilized to generate functional particles with inherent binding activity and label function. Additionally, particle yield was effectively optimized by analyzing various refolding and bacterial production conditions. Our results clearly demonstrate that this simple biological method of producing functional ferritin-based particles is flexible, and different types of binding moieties can be applied by adjusting the production conditions. 相似文献
49.
Ville-Pekka Eronen Rolf O. Lindén Anna Lindroos Mirella Kanerva Tero Aittokallio 《PloS one》2010,5(7)
Recent technological developments in genetic screening approaches have offered the means to start exploring quantitative genotype-phenotype relationships on a large-scale. What remains unclear is the extent to which the quantitative genetic interaction datasets can distinguish the broad spectrum of interaction classes, as compared to existing information on mutation pairs associated with both positive and negative interactions, and whether the scoring of varying degrees of such epistatic effects could be improved by computational means. To address these questions, we introduce here a computational approach for improving the quantitative discrimination power encoded in the genetic interaction screening data. Our matrix approximation model decomposes the original double-mutant fitness matrix into separate components, representing variability across the array and query mutants, which can be utilized for estimating and correcting the single-mutant fitness effects, respectively. When applied to three large-scale quantitative interaction datasets in yeast, we could improve the accuracy of scoring various interaction classes beyond that obtained with the original fitness data, especially in synthetic genetic array (SGA) and in genetic interaction mapping (GIM) datasets. In addition to the known pairs of interactions used in the evaluation of the computational approach, a number of novel interaction pairs were also predicted, along with underlying biological mechanisms, which remained undetected by the original datasets. It was shown that the optimal choice of the scoring function depends heavily on the screening approach and on the interaction class under analysis. Moreover, a simple preprocessing of the fitness matrix could further enhance the discrimination power of the epistatic miniarray profiling (E-MAP) dataset. These systematic evaluation results provide in-depth information on the optimal analysis of the future, large-scale screening experiments. In general, the modeling framework, enabling accurate identification and classification of genetic interactions, provides a solid basis for completing and mining the genetic interaction networks in yeast and other organisms. 相似文献
50.
Populations of the autumnal moth, Epirrita autumnata, exhibit cycles with high amplitudes in northernmost Europe, culminating in devastating outbreak densities at favourable
sites. Parasitism by hymenopteran parasitoids has been hypothesised to operate with a delayed density dependence capable of
producing the observed dynamics. It has also been hypothesised that insects in crowded conditions invest greatly in their
immunity as a counter-measure to increased risk of parasitism and pathogen infections. Furthermore, inducible plant defences
consequent to grazing by herbivorous insects may be linked to the performance of parasitoids and pathogens through increased
immunocompetence of the herbivore feeding on the foliage, in which the defence induction has taken place. At ten sampling
sites, we quantified larval abundance, outbreak status and percentage larval parasitism during an extended peak phase of a
population cycle. These population level covariates, together with an individual pupal mass, were used to explain differences
in the immune defence, measured as an encapsulation reaction to artificial antigen. We also conducted a field study for an
investigation of the susceptibility of autumnal moth pupae to naturally occurring pupal parasitoids. We did not find obvious
differences between the encapsulation rate of autumnal moths originating from the sites with different past and current larval
densities and risks for parasitism. The best ranked statistical models included pupal mass and outbreak status as explanatory
variables, although both showed only slight effects on the encapsulation rate. The host resistance test revealed positive
relationships between the encapsulation rate, body size and percentage parasitism of the exposed pupae, indicating that pupal
parasitoids chose, and/or survived better, in large host individuals irrespective of their encapsulation ability. Thus, our
results do not provide support for the hypothesis that variation in the immune function drives or modulates population cycles
of autumnal moths.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorised users. 相似文献