Search results for "complex"
showing 10 items of 5889 documents
Networks in biological systems: An investigation of the Gene Ontology as an evolving network
2009
Many biological systems can be described as networks where diFFerent elements interact, in order to perform biological processes. We introduce a network associated with the Gene Ontology. Specifically, we construct a correlation-based network where the vertices are the terms of the Gene Ontology and the link between each two terms is weighted on the basis of the number of genes that they have in common. We analyze a filtered network obtained from the correlation-based network and we characterize its evolution over different releases of the Gene Ontology.
Protein Interaction Networks and Disease: Highlights of the 3rd Challenges in Computational Biology Meeting
2017
Cellular functions are managed by a complex network of protein interactions, the malfunction of which may derive in disease phenotypes. In spite of the incompleteness and noise present in our current protein interaction maps, computational biologists are making strenuous efforts to extract knowledge from these intricate networks and, through their integration with other types of biological data, expedite the development of novel and more effective treatments against human disorders. The 3rd Challenges in Computational Biology meeting revolved around the Protein Interaction Networks and Disease subject, bringing expert network biologists to the city of Mainz, Germany to debate the current st…
Textual data compression in computational biology: Algorithmic techniques
2012
Abstract In a recent review [R. Giancarlo, D. Scaturro, F. Utro, Textual data compression in computational biology: a synopsis, Bioinformatics 25 (2009) 1575–1586] the first systematic organization and presentation of the impact of textual data compression for the analysis of biological data has been given. Its main focus was on a systematic presentation of the key areas of bioinformatics and computational biology where compression has been used together with a technical presentation of how well-known notions from information theory have been adapted to successfully work on biological data. Rather surprisingly, the use of data compression is pervasive in computational biology. Starting from…
Plant Pigments: Properties, Analysis, Degradation
2005
Publisher Summary This chapter discusses the molecular structures, the general physicochemical properties of plant pigments, and the mechanisms involved in pigment degradation. The invasive and noninvasive methods used for pigment analysis, including the mechanisms involved in pigment degradation, are reviewed. The chapter presents different analytical methods that can be used to identify pigments. All the methods are invasive techniques that are time consuming and often expensive. To reduce sampling and analytical costs, and to speed up the analyses, noninvasive analytical procedures have been developed with the aim to characterize the pigment content of samples, and in the case of food pr…
Genetic relationships between sympatric and allopatric Coregonus ciscoes in North and Central Europe
2021
Abstract Background Sympatric speciation along ecological gradients has been studied repeatedly, in particular in freshwater fishes. Rapid post-glacial ecological divergence has resulted in numerous endemic species or ecologically distinct populations in lakes of the temperate zones. Here, we focus on the Baltic cisco (Coregonus albula) complex, to study the genetic similarity among two pairs of sympatric autumn- and spring-spawning populations from post-glacial German Lakes Stechlin and Breiter Luzin. For comparison, we included a similar pair of sympatric populations from the Swedish Lake Fegen. We wanted to explore potential genetic similarities between the three sympatric cisco populati…
Influence of carbon and nutrient additions on a decomposer food chain and the growth of pine seedlings in microcosms
2001
Abstract Because of N deposition plant production is becoming increasingly limited by other nutrients in boreal forests. At the same time more C is suggested to become available for below-ground food webs because of enhanced CO2 fixation. We studied the effects of carbon and nutrient addition on a fungus–nematode food chain and on the growth of mycorrhizal or nonmycorrhizal pine seedlings (Pinus sylvestris L.) in microcosms with N-rich mineral soil and a humus layer. The role of the food chain and mycorrhizal fungi for pine growth was tested in a smaller set-up. The total pine biomass was not N-limited at the scale of two experimental growing seasons. In accordance with established knowledg…
Interannual Variability of Biomass (SMOS Vegetation Optical Depth) Over the Contiguous United States
2021
Interannual variability in biomass represented by SMOS vegetation optical depth (VOD) and precipitation was assessed over the Contiguous United States. The greatest interannual variability in both VOD and precipitation occurred in shrubs and herbaceous (grasslands), with forests the least variable. At a continental scale, VOD was strongly correlated with annual precipitation. Results showed a significant correlation coefficient (∼ 0.93) between interannual variability of precipitation and biomass, indicating that the interannual variability of precipitation could be a good predictor of the interannual variability of biomass.
A modified niche model for generating food webs with stage-structured consumers : The stabilizing effects of life-history stages on complex food webs
2021
1. Almost all organisms grow in size during their lifetime and switch diets, trophic positions, and interacting partners as they grow. Such ontogenetic development introduces life-history stages and flows of biomass between the stages through growth and reproduction. However, current research on complex food webs rarely considers life-history stages. The few previously proposed methods do not take full advantage of the existing food web structural models that can produce realistic food web topologies. 2. We extended the niche model by Williams & Martinez (2000) to generate food webs that included trophic species with a life-history stage structure. Our method aggregated trophic species …
Manganese(II) complexes of scorpiand-like azamacrocycles as MnSOD mimics.
2011
Mn(II) complexes of scorpiand-type azamacrocycles constituted by a tretrazapyridinophane core appended with an ethylamino tail including 2- or 4-quinoline functionalities show very appealing in vitro SOD activity. The observed behaviour is related to structural and electrochemical parameters.
The evolution of metazoan α-carbonic anhydrases and their roles in calcium carbonate biomineralization
2014
The carbonic anhydrase (CA; EC 4.2.1.1) superfamily is a class of ubiquitous metallo-enzymes that catalyse the reversible hydration of carbon dioxide. The ?-CA family, present in all metazoan clades, is a key enzyme involved in a wide range of physiological functions including pH regulation, respiration, photosynthesis, and biocalcification. This paper reviews the evolution of the ?-CA family, with an emphasis on metazoan ?-CA members involved in biocalcification. Phylogenetic analyses reveal a complex evolutionary history of ?-CAs, and suggest ?-CA was independently co-opted into a variety of skeleton forming roles (e.g. as a provider of HCO3? ions, a structural protein, a nucleation activ…