Últimos itens adicionados do Acervo: Proceedings Nature

Nature é uma das mais prestigiosas e antigas revistas científicas do mundo: sua primeira edição é de 4 de novembro de 1869. Entre as inúmeras descobertas científicas publicadas na Nature estão a dos raios X, da estrutura em dupla hélice do ADN e o buraco na camada de ozônio.

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‣ Music can reduce cognitive dissonance

Nobuo Masataka; Leonid Perlovsky
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Manuscript
Português
The fundamental cognitive functions of music in the brain have not been known and evolutionary reasons for musical abilities seem mysterious. A recent hypothesis suggested that a fundamental function of music has been to help mitigating cognitive dissonances. A cognitive dissonance is "a discomfort caused by holding conflicting cognitions" simultaneously; it usually leads to devaluation of conflicting knowledge. Since every concept implies some degree of contradictions to other knowledge, unmitigated cognitive dissonances could prevent evolution of cognition. Thus music might be fundamental for the evolution of cognition. Here we provide experimental confirmation of this hypothesis using a classical paradigm known to induce a cognitive dissonance and devaluation of a dissonant object; in presence of music devaluation has not occurred.

‣ A potential diagnostic biomarker: Proteasome LMP2/b1i-differential expression in human uterus neoplasm

Takuma Hayashi; Akiko Horiuchi; Hiroyuki Aburatani; Nobuo Yaegashi; Susumu Tonegawa; Ikuo Konishi
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Manuscript
Português
Uterine leiomyosarcoma (ULMS) develops more often in the muscle tissue layer of the uterine body than in the uterine cervix. The development of gynecologic tumors is often correlated with female hormone secretion; however, the development of uterine ULMS is not substantially correlated with hormonal conditions, and the risk factors are not yet known. Importantly, a diagnostic-biomarker which distinguishes malignant ULMS from benign tumor leiomyoma (LMA) is yet to be established. Accordingly, it is necessary to analyze risk factors associated with uterine ULMS, to establish a treatment method. Proteasome low-molecular mass polypeptide 2(LMP2)/b1i-deficient mice spontaneously develop uterine LMS, with a disease prevalence of ~40% by 14 months of age. We found LMP2/b1i expression to be absent in human LMS, but present in human LMA. Therefore, defective-LMP2/b1i expression may be one of the risk factors for ULMS. LMP2/b1i is a potential diagnostic-biomarker for uterine ULMS, and may be a targeted-molecule for a new therapeutic approach.

‣ Quantum Genetics and Quantum Automata Models of Quantum-Molecular Evolution Involved in the Evolution of Organisms and Species

I. C. Baianu
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Manuscript
Português
Previous theoretical or general approaches to the problems of Quantum Genetics and Molecular Evolution are considered in this article from the point of view of Quantum Automata Theory first published by the author in 1971 and further developed in several recent articles. The representation of genomes and Interactome networks in categories of many-valued logic LMn –algebras that are naturally transformed during biological evolution, or evolve through interactions with the environment provide a new insight into the mechanisms of molecular evolution, as well as organismal evolution, in terms of sequences of quantum automata. Phenotypic changes are expressed only when certain environmentally-induced quantum-molecular changes are coupled with an internal re-structuring of major submodules of the genome and Interactome networks related to cell cycling and cell growth. Contrary to the commonly held view of `standard’ Darwinist models of evolution, the evolution of organisms and species occurs through coupled multi-molecular transformations induced not only by the environment but actually realized through internal re-organizations of genome and interactome networks. The biological, evolutionary processes involve certain epigenetic transformations that are responsible for phenotypic expression of the genome and Interactome transformations initiated at the quantum-molecular level. It can thus be said that only quantum genetics can provide correct explanations of evolutionary processes that are initiated at the quantum--multi-molecular levels and propagate to the higher levels of organismal and species evolution. Biological evolution should be therefore regarded as a multi-scale process which is initiated by underlying quantum (coupled) multi-molecular transformations of the genomic and interactomic networks...

‣ Structure based de novo design of IspD inhibitors as anti-tubercular agents

Rohith Anand Varikoti; Rahul P. Gangwal; Gaurao V. Dhoke; Venkata Krishnan Ramaswamy; Abhay T. Sangamwar
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Manuscript
Português
Tuberculosis is one of the leading contagious diseases, caused by Mycobacterium tuberculosis. Despite improvements in anti-tubercular agents, it remains one of the most prevalent infectious diseases worldwide, responsible for a total of 1.6 million deaths annually. The emergence of multidrug resistant strains highlighted the need of discovering novel drug targets for the development of anti-tubercular agents. 2-C-methyl-D-erythritol-4-phosphate cytidyltransferase (IspD) is an enzyme involved in MEP pathway for isoprenoid biosynthesis, which is considered an attractive target for the discovery of novel antibiotics for its essentiality in bacteria and absence in mammals. In the present study, we have employed structure based drug design approach to develop novel and potent inhibitors for IspD receptor. To explore binding affinity and hydrogen bond interaction between the ligand and active site of IspD receptor, docking studies were performed. ADMET and synthetic accessibility filters were used to screen designed molecules. Finally, ten compounds were selected and subsequently submitted for the synthesis and in vitro studies as IspD inhibitors.

‣ A unified mechanistic model of niche, neutrality and violation of the competitive exclusion principle

Lev V. Kalmykov; Vyacheslav L. Kalmykov
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Manuscript
Português
The origin of species richness is one of the most widely discussed questions in ecology. The absence of unified mechanistic model of competition makes difficult our deep understanding of this subject. Here we show such a two-species competition model that unifies (i) a mechanistic niche model, (ii) a mechanistic neutral (null) model and (iii) a mechanistic violation of the competitive exclusion principle. Our model is an individual-based cellular automaton. We demonstrate how two trophically identical and aggressively propagating species can stably coexist in one stable homogeneous habitat without any trade-offs in spite of their 10% difference in fitness. Competitive exclusion occurs if the fitness difference is significant (approximately more than 30%). If the species have one and the same fitness they stably coexist and have similar numbers. We conclude that this model shows diffusion-like and half-soliton-like mechanisms of interactions of colliding population waves. The revealed mechanisms eliminate the existing contradictions between ideas of niche, neutrality and cases of violation of the competitive exclusion principle.

‣ Network-based analyses of Huntington’s Disease

Ravi K. Kalathur; Matthias E. Futschik
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Poster
Português
The use of high-throughput technologies has provided us with large amounts of data for _Huntington's disease_ (HD), especially at the gene and protein levels. As phenotypic changes in HD may not just be due to the activity of individual genes but interrelated alterations of whole molecular networks, it is important to systematically analyse and represent accumulated data in a network-based approach. Methods: To analyse and visualise protein interaction networks through a dedicated database to HD, we have established "HDNetDB": http://hdnetdb.sysbiolab.eu. This platform will not only help to understand molecular mechanisms better, but also assist in identifying potential molecular markers involved in HD. We further identified both pathways as well as gene ontology (GO) annotations that are enriched in HD and constructed networks of the pathways and enriched GO annotations. Results: Our integrative network based methodology helped us to identify pathways and networks that are specific to the HD and may lead to the identification of novel molecular targets. Follow-up analyses of molecular changes will distinguish between potential causes and effects in HD. We hope that the constructed database will help researchers worldwide to find a cure for HD.

‣ Development of Java based graphical user interface for Diagnosis of Hepatitis UsingI Mixture of Expert

M Shankaracharya; Suchitra Kumari; Ambarish S. Vidyarthi
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Poster
Português
Hepatitis is deadly, and the fifth leading cause of death after heart disease, stroke, chest disease and cancer. Worldwide, 1.5 million deaths per year have been estimated. Detection of hepatitis is a big problem for general practitioners. An expert doctor commonly makes decisions by evaluating the current test results of a patient or by comparing the patient with others with the same condition with reference to the previous decisions. Many machine learning and data mining techniques have been designed for the automatic diagnosis of hepatitis. However, no one tool is available to the general population for the diagnosis of Hepatitis. Hence, a graphical user interface-enabled tool needs to be developed, through which medical practitioners can feed patient data easily and find hepatitis diagnoses instantly and accurately. Methods: In this study a hepatitis dataset was taken from the UCI machine repository database with a total of 20 attributes of two classes, Affected and Not Affected. Results and Conclusion: The models have been generated with a mixture of experts as a classification method for the diagnosis of hepatitis. Very good accuracy has been observed in the generated models. Finally, the model having the least minimum square error was selected. This model was then linked with GUI for the design of tools for hepatitis prediction.

‣ An insight into the kinships of the fungi

Riddhi Datta; Joy Sarkar; Krishnendu Acharya
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Manuscript
Português
The evolutionary origin of fungi is important in determining the phylogenetic relationships between fungi, animals and plants. However, determining the true relationship of fungi has been somewhat difficult owing to their simple morphology and presence of convergent characters. With the advent of newer molecular techniques, analysis of conserved protein sequences, cytochrome systems, mitochondrial and nuclear genetic material and rRNAs are being employed in elucidating phylogenetic kinships among the eukaryotes. These emerging evidences suggest that the derivation of the fungi from plants or algae would require more evolutionary changes than its derivation from protozoa, the unicellular ancestor of the animals. To gain an overview of the current state of the science, we have extensively reviewed the existing literatures and it appeared to us that fungi are more closely related to animals than to plants.

‣ Human neuromaturation, juvenile extreme energy liability, and adult cognition/cooperation

John Skoyles
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Manuscript
Português
Human childhood and adolescence is the period in which adult cognitive competences (including those that create the unique cooperativeness of humans) are acquired. It is also a period when neural development puts a juvenile’s survival at risk due to the high vulnerability of their brain to energy shortage. The brain of a 4 year-old human uses ≈50% of its total energy expenditure (TEE) (cf. adult ≈12%). This brain expensiveness is due to (1) the brain making up ≈6% of a 4 year-old body compared to 2% in an adult, and (2) increased energy metabolism that is ≈100% greater in the gray matter of a child than in an adult (a result of the extra costs of synaptic neuromaturation). The high absolute number of neurons in the human brain requires as part of learning a prolonged neurodevelopment. This refines inter- and intraarea neural networks so they become structured with economical “small world” connectivity attributes (such as hub organization and high cross-brain differentiation/integration). Once acquired, this connectivity enables highly complex adult cognitive capacities. Humans evolved as hunter-gatherers. Contemporary hunter-gatherers (and it is also likely Middle Paleolithic ones) pool high energy foods in an egalitarian manner that reliably supported mothers and juveniles with high energy intake. This type of sharing unique to humans protects against energy shortage happening to the immature brain. This cooperation that protects neuromaturation arises from adults having the capacity to communicate and evaluate social reputation...

‣ Extreme energy lability in human children: An overlooked and central aspect of human biology

John Skoyles
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Conferência ou Objeto de Conferência
Português
A four year old child devotes half their total energy expenditure (TEE) to their brains. Even by 10 years-of-age it is still 30% (compared to an adult’s ≈12%). This extreme energy use results from a high brain/body size ratio – combined with a doubling of cerebral gray matter energy utilization (due to synaptic exuberance during cognitive neuromaturation). With extreme energy expenditure goes extreme vulnerability to hypoglycemia: (1) children become hypoglycemic after 24-36 hours of fast (compared to 60-72 hours in adults), and (2) their brains suffer neurological impairment (shown in disrupted P300 potentials) at a lower decrease in plasma glucose: 3.6 - 4.2 mmol L-1 in children rather than < 3.0 mmol L-1 in adults (against a normal level in both of 4.6-4.8 mmol L-1). Human biology has selected adaptations that buffer and protect children from this energy lability. A physiological one is that energy metabolism in skeletal muscles is biased towards using fatty acids, and this minimizes uptake competition of plasma glucose between muscles and the brain. Behavioral adaptations (in human hunter-gatherers) include adults cooperatively pooling high energy foods with juveniles for ≈15 years...

‣ Fundamental Principles of Neural Organization of Cognition

Leonid I. Perlovsky
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Manuscript
Português
The manuscript advances a hypothesis that there are few fundamental principles of neural organization of cognition, which explain several wide areas of the cognitive functioning. We summarize the fundamental principles, experimental, theoretical, and modeling evidence for these principles, relate them to hypothetical neural mechanisms, and made a number of predictions. We consider cognitive functioning including concepts, emotions, drives-instincts, learning, “higher” cognitive functions of language, interaction of language and cognition, role of emotions in this interaction, the beautiful, sublime, and music. Among mechanisms of behavior we concentrate on internal actions in the brain, learning and decision making. A number of predictions are made, some of which have been previously formulated and experimentally confirmed, and a number of new predictions are made that can be experimentally tested. Is it possible to explain a significant part of workings of the mind from a few basic principles, similar to how Newton explained motions of planets? This manuscript summarizes a part of contemporary knowledge toward this goal.

‣ Intrarectal administration of hCG (Human Choriogonadotropin) and fat loss as assessed by Dual energy X-ray absorptiometry (DXA) in experimental animals.

Daniel Belluscio; Ezequiel Klimovsky; Alejandro Kaniuk; Sergio Vaney
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Manuscript
Português
Our studies suggest that in experimental animals, submitted to a hypocaloric diet, the intrarectal administration of hCG (Human Chorionic Gonadotropin) decreases body fat and increases lean mass content in relative values to a greater extent that control animals who did not receive hCG.

‣ P300- like event related potential amplitude in rats is a correlate of conditioned reinforcement

William D. Klipec; Steven Faux
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Manuscript
Português
We have developed a methodology for recording a robust P300 event related potential (ERP) in rats. In these experiments a contingency shaped model of the human “oddball’ paradigm was employed in which rats were shaped to press a lever for food reinforcement signaled by the click of the pellet dispenser. A target tone cued the insertion of the lever that retracted after 1­sec or immediately following a single reinforced response, while a non­target tone was randomly presented. Brain activity was recorded through stainless steel electrodes implanted 1mm below the skull. Here, we compared the amplitude of the P300 response to the click of the pellet dispenser to the amplitude of the P300 response to the target and non­target tones. We found that the amplitude to food click was significantly greater that the amplitude to the target tone that cued lever insertion. Since the food click is more proximal to the primary reinforcer than the lever tone, it is a stronger conditioned reinforcer than the lever tone that sets the occasion for the food click. Accordingly we suggest that the P300 in rats is a correlate of conditioned reinforcement.

‣ Complex Systems Analysis of Arrested Neural Cell Differentiation during Development and Analogous Cell Cycling Models in Carcinogenesis

I C. Baianu; V. I. Prisecaru
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Manuscript
Português
A new approach to the modular, complex systems analysis of nonlinear dynamics of arrested neural cell Differentiation--induced cell proliferation during organismic development and the analogous cell cycling network transformations involved in carcinogenesis is proposed. Neural tissue arrested differentiation that induces cell proliferation during perturbed development and Carcinogenesis are complex processes that involve dynamically inter-connected biomolecules in the intercellular, membrane, cytosolic, nuclear and nucleolar compartments. Such 'dynamically inter-connected' biomolecules form numerous inter-related pathways referred to as 'molecular networks'. One such family of signaling pathways contains the cell cyclins. Cyclins are proteins that link several critical pro-apoptotic and other cell cycling/division components, including the tumor suppressor gene TP53 and its product, the Thomsen-Friedenreich antigen (T antigen), Rb, mdm2, c-Myc, p21, p27, Bax, Bad and Bcl-2, which play major roles in various neoplastic transformations of many tissues. The novel theoretical analysis presented here is based on recently published studies of arrested cell differentiation that normally leads to neural system formation during early developmental stages; the perturbed development may involve cyclin signaling and cell cycling responsible for rapidly induced cell proliferation without differentiation into neural cells in such experimental studies.

‣ Optogenetic control of genetically-targeted pyramidal neuron activity in prefrontal cortex

Michael V. Baratta; Shinya Nakamura; Peter Dobelis; Matthew B. Pomrenze; Samuel D. Dolzani; Donald C. Cooper
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Manuscript
Português
A salient feature of prefrontal cortex organization is the vast diversity of cell types that support the temporal integration of events required for sculpting future responses. A major obstacle in understanding the routing of information among prefrontal neuronal subtypes is the inability to manipulate the electrical activity of genetically defined cell types over behaviorally relevant timescales and activity patterns. To address these constraints, we present here a simple approach for selective activation of prefrontal excitatory neurons in both in vitro and in vivo preparations. Rat prelimbic pyramidal neurons were genetically targeted to express a light-­activated nonselective cation channel, channelrhodopsin-­2, or a light-­driven inward chloride pump, halorhodopsin, which enabled them to be rapidly and reversibly activated or inhibited by pulses of light. These light responsive tools provide a spatially and temporally precise means of studying how different cell types contribute to information processing in cortical circuits. Our customized optrodes and optical commutators for in vivo recording allow for efficient light delivery and recording and can be requested at www.neuro-­cloud.net/nature-precedings/baratta.

‣ Computational system biology

Ankit Geete
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Conferência ou Objeto de Conferência
Português
Systems biology is a multi-disciplinary field that deals with mechanisms involved in complex biological processes by considering them as integrated systems of multiple interacting components. The huge amount of data involved in this study necessitates the use of computational tools.

‣ Mechanistic mechanisms of competition and biodiversity

Lev V. Kalmykov; Vyacheslav L. Kalmykov
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Manuscript
Português
The nature of competition and biodiversity are open basic questions since Darwin. To investigate mechanisms of interspecific competition and their contribution in biodiversity as closely as possible we offer a white-box modelling method based on physically interpreted ecological axioms. These models are implemented as deterministic individual-based cellular automata and able to give a direct physico-mechanistic insight into studied phenomena. Competition of two trophically identical but fitness different species, competing for one limiting resource in one stable uniform habitat (which is closed for immigration, emigration, predation, herbivory and parasitism) has been investigated in conditions, which are the most unfavourable for their coexistence. The species are per capita identical in fecundity, ontogeny, regeneration features of microhabitats, and in habitat requirements. We have modelled following 8 mechanistic mechanisms of interspecific competition: 1. A case of the competitive exclusion when competing species differ only in fitness. 2. Coexistence based on periodic dominance changeovers as a consequence of environmental changes. Competing species differ only in fitness. 3. A strong violation of the competitive exclusion principle due to the lowered fecundity of both competitors. Competing species differ only in fitness. 4. Coexistence based on the competition–colonisation trade-off when greater fitness is compensated by r-strategy. 5. A competition–colonisation trade-off based on differences in ontogeny. 6. Competitive exclusion when recessive species drives out the dominant one having four times greater fecundity than the dominant one in stable environment (the greater fitness cannot compensate r-strategy). 7. An inverted competitive exclusion when recessive species drives out the dominant one by strategy of anticipatory deprivation of resources for competitor’s offsprings propagation. Recessive species drives out the dominant one in stable environment and both competing species have identical fecundity (tripod neighbourhood). Paradoxically...

‣ Complex Systems Analysis of Arrested Neural Cell Differentiation during Development and Analogous Cell Cycling Models in Carcinogenesis

V. I. Prisecaru; I C. Baianu
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Manuscript
Português
A new approach to the modular, complex systems analysis of nonlinear dynamics of arrested neural cell Differentiation--induced cell proliferation during organismic development and the analogous cell cycling network transformations involved in carcinogenesis is proposed. Neural tissue arrested differentiation that induces cell proliferation during perturbed development and Carcinogenesis are complex processes that involve dynamically inter-connected biomolecules in the intercellular, membrane, cytosolic, nuclear and nucleolar compartments. Such 'dynamically inter-connected' biomolecules form numerous inter-related pathways referred to as 'molecular networks'. One such family of signaling pathways contains the cell cyclins. Cyclins are proteins that link several critical pro-apoptotic and other cell cycling/division components, including the tumor suppressor gene TP53 and its product, the Thomsen-Friedenreich antigen (T antigen), Rb, mdm2, c-Myc, p21, p27, Bax, Bad and Bcl-2, which play major roles in various neoplastic transformations of many tissues. The novel theoretical analysis presented here is based on recently published studies of arrested cell differentiation that normally leads to neural system formation during early developmental stages; the perturbed development may involve cyclin signaling and cell cycling responsible for rapidly induced cell proliferation without differentiation into neural cells in such experimental studies.

‣ Quantum Genetics and Quantum Automata Models of Quantum-Molecular Evolution Involved in the Evolution of Organisms and Species

I. C. Baianu
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Manuscript
Português
Previous theoretical or general approaches to the problems of Quantum Genetics and Molecular Evolution are considered in this article from the point of view of Quantum Automata Theory first published by the author in 1971 and further developed in several recent articles. The representation of genomes and Interactome networks in categories of many-valued logic LMn –algebras that are naturally transformed during biological evolution, or evolve through interactions with the environment provide a new insight into the mechanisms of molecular evolution, as well as organismal evolution, in terms of sequences of quantum automata. Phenotypic changes are expressed only when certain environmentally-induced quantum-molecular changes are coupled with an internal re-structuring of major submodules of the genome and Interactome networks related to cell cycling and cell growth. Contrary to the commonly held view of 'standard’ Darwinist models of evolution, the evolution of organisms and species occurs through coupled multi-molecular transformations induced not only by the environment but actually realized through internal re-organizations of genome and interactome networks. The biological, evolutionary processes involve certain epigenetic transformations that are responsible for phenotypic expression of the genome and Interactome transformations initiated at the quantum-molecular level. It can thus be said that only quantum genetics can provide correct explanations of evolutionary processes that are initiated at the quantum--multi-molecular levels and propagate to the higher levels of organismal and species evolution. Biological evolution should be therefore regarded as a multi-scale process which is initiated by underlying quantum (coupled) multi-molecular transformations of the genomic and interactomic networks...

‣ A Note On The Denisova Cave mtDNA Sequence

Niccolo Caldararo; Michael Guthrie
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Manuscript
Português
The recently published Altai fossil sequence from Denisova Cave was purported to be so different from anatomically modern humans, yet have the physiological landmarks of that species designation. When the published sequence was examined it was found that segments in the mtDNA hypervariable regions could be found to align with that of anatomically modern humans if one introduced an insertion at a position found in Neanderthals. Some other points of interest arise from a reconsideration of the sequences for other published samples and Neanderthals from the same perspective.