42 research outputs found
A Rapid Soft Computing Approach to Dimensionality Reduction in Model Construction
A rapid soft computing method for dimensionality reduction of data sets is presented. Traditional approaches usually base on factor or principal component analysis. Our method applies fuzzy cluster analysis and approximate reasoning instead, and thus it is also viable to nonparametric and nonlinear models. Comparisons are drawn between the methods with two empiric data sets.Peer reviewe
A Case Study on Time-Interval Fuzzy Cognitive Maps in a Complex Organization
Temporal issues within modeling organizational systems are examined generally and with fuzzy cognitive maps. These maps give the opportunity to consider temporal factors when studying organizational models. The knowledge we gain about the system is useful when the aim is not to optimize time intervals in well-known and instrumented contexts, but also to discover the behavior of the system while different temporal factors are implemented by the management. We will present an adapted resolution for including these factors as key elements in organizational models with fuzzy cognitive map examples for middle and back office application.Peer reviewe
Banking applications of FCM models
Fuzzy Cognitive Map (FCMs) is an appropriate tool to describe, qualitatively analyze or simulate the behavior of complex systems. FCMs are bipolar fuzzy graphs: their building blocks are the concepts and the arcs. Concepts represent the most important components of the system, the weighted arcs define the strength and direction of cause-effect relationships among them. FCMs are created by experts in several cases. Despite the best intention the models may contain subjective information even if it was created by multiple experts. An inaccurate model may lead to misleading results, therefore it should be further analyzed before usage. Our method is able to automatically modify the connection weights and to test the effect of these changes. This way the hidden behavior of the model and the most influencing concepts can be mapped. Using the results the experts may modify the original model in order to achieve their goal. In this paper the internal operation of a department of a bank is modeled by FCM. The authors show how the modification of the connection weights affect the operation of the institute. This way it is easier to understand the working of the bank, and the most threatening dangers of the system getting into an unstable (chaotic or cyclic state) can be identified and timely preparations become possible. © Springer Nature Switzerland AG 2019.Peer reviewe
Structure and characterization of a novel chicken biotin-binding protein A (BBP-A)
Background.
The chicken genome contains a BBP-A gene showing similar characteristics to avidin family genes. In a previous study we reported that the BBP-A gene may encode a biotin-binding protein due to the high sequence similarity with chicken avidin, especially at regions encoding residues known to be located at the ligand-binding site of avidin.
Results.
Here, we expand the repertoire of known macromolecular biotin binders by reporting a novel biotin-binding protein A (BBP-A) from chicken. The BBP-A recombinant protein was expressed using two different expression systems and purified with affinity chromatography, biochemically characterized and two X-ray structures were solved – in complex with D-biotin (BTN) and in complex with D-biotin D-sulfoxide (BSO). The BBP-A protein binds free biotin with high, "streptavidin-like" affinity (Kd ~ 10-¹³ M), which is about 50 times lower than that of chicken avidin. Surprisingly, the affinity of BBP-A for BSO is even higher than the affinity for BTN. Furthermore, the solved structures of the BBP-A – BTN and BBP-A – BSO complexes, which share the fold with the members of the avidin and lipocalin protein families, are extremely similar to each other.
Conclusion.
BBP-A is an avidin-like protein having a β-barrel fold and high affinity towards BTN. However, BBP-A differs from the other known members of the avidin protein family in thermal stability and immunological properties. BBP-A also has a unique ligand-binding property, the ability to bind BTN and BSO at comparable affinities. BBP-A may have use as a novel material in, e.g. modern bio(nano)technological applications.peerReviewe
Parvovirus nonstructural protein 2 interacts with chromatin-regulating cellular proteins
Autonomous parvoviruses encode at least two nonstructural proteins, NS1 and NS2. While NS1 is linked to important nuclear processes required for viral replication, much less is known about the role of NS2. Specifically, the function of canine parvovirus (CPV) NS2 has remained undefined. Here we have used proximity-dependent biotin identification (BioID) to screen for nuclear proteins that associate with CPV NS2. Many of these associations were seen both in noninfected and infected cells, however, the major type of interacting proteins shifted from nuclear envelope proteins to chromatin-associated proteins in infected cells. BioID interactions revealed a potential role for NS2 in DNA remodeling and damage response. Studies of mutant viral genomes with truncated forms of the NS2 protein suggested a change in host chromatin accessibility. Moreover, further studies with NS2 mutants indicated that NS2 performs functions that affect the quantity and distribution of proteins linked to DNA damage response. Notably, mutation in the splice donor site of the NS2 led to a preferred formation of small viral replication center foci instead of the large coalescent centers seen in wild-type infection. Collectively, our results provide insights into potential roles of CPV NS2 in controlling chromatin remodeling and DNA damage response during parvoviral replication.Peer reviewe
Structure and characterization of a novel chicken biotin-binding protein A (BBP-A)
BACKGROUND: The chicken genome contains a BBP-A gene showing similar characteristics to avidin family genes. In a previous study we reported that the BBP-A gene may encode a biotin-binding protein due to the high sequence similarity with chicken avidin, especially at regions encoding residues known to be located at the ligand-binding site of avidin. RESULTS: Here, we expand the repertoire of known macromolecular biotin binders by reporting a novel biotin-binding protein A (BBP-A) from chicken. The BBP-A recombinant protein was expressed using two different expression systems and purified with affinity chromatography, biochemically characterized and two X-ray structures were solved – in complex with D-biotin (BTN) and in complex with D-biotin D-sulfoxide (BSO). The BBP-A protein binds free biotin with high, "streptavidin-like" affinity (K(d )~ 10(-13 )M), which is about 50 times lower than that of chicken avidin. Surprisingly, the affinity of BBP-A for BSO is even higher than the affinity for BTN. Furthermore, the solved structures of the BBP-A – BTN and BBP-A – BSO complexes, which share the fold with the members of the avidin and lipocalin protein families, are extremely similar to each other. CONCLUSION: BBP-A is an avidin-like protein having a β-barrel fold and high affinity towards BTN. However, BBP-A differs from the other known members of the avidin protein family in thermal stability and immunological properties. BBP-A also has a unique ligand-binding property, the ability to bind BTN and BSO at comparable affinities. BBP-A may have use as a novel material in, e.g. modern bio(nano)technological applications
Progression of herpesvirus infection remodels mitochondrial organization and metabolism
Viruses target mitochondria to promote their replication, and infection-induced stress during the progression of infection leads to the regulation of antiviral defenses and mitochondrial metabolism which are opposed by counteracting viral factors. The precise structural and functional changes that underlie how mitochondria react to the infection remain largely unclear. Here we show extensive transcriptional remodeling of protein-encoding host genes involved in the respiratory chain, apoptosis, and structural organization of mitochondria as herpes simplex virus type 1 lytic infection proceeds from early to late stages of infection. High-resolution microscopy and interaction analyses unveiled infection-induced emergence of rough, thin, and elongated mitochondria relocalized to the perinuclear area, a significant increase in the number and clustering of endoplasmic reticulum-mitochondria contact sites, and thickening and shortening of mitochondrial cristae. Finally, metabolic analyses demonstrated that reactivation of ATP production is accompanied by increased mitochondrial Ca2+ content and proton leakage as the infection proceeds. Overall, the significant structural and functional changes in the mitochondria triggered by the viral invasion are tightly connected to the progression of the virus infection
Statistical Approach to Fuzzy Cognitive Maps
Fuzzy cognitive maps are studied from statistical standpoint. An analogy between these maps and linear regression and logistic regression models is drawn. Practical examples are also provided.Peer reviewe
A Statistical Random Variable Approach to Fuzzy Cognitive Map Modeling
FUZZ-IEEE Conference, New Orleans, US