The prebiotic replication of information-coding molecules is a central problem concerning life’s origins. Here, we report that amyloids composed of short peptides can direct the sequence-selective, regioselective and stereoselective condensation of amino acids. The addition of activated DL-arginine and DL-phenylalanine to the peptide RFRFR-NH2 in the presence of the complementary template peptide Ac-FEFEFEFE-NH2 yields the isotactic product FRFRFRFR-NH2, 1 of 64 possible triple addition products, under conditions in which the absence of template yields only single and double additions of mixed stereochemistry. The templating mechanism appears to be general in that a different amyloid formed by (Orn)V(Orn)V(Orn)V(Orn)V-NH2 and Ac-VDVDVDVDV-NH2 is regioselective and stereoselective for N-terminal, L-amino-acid addition while the ornithine-valine peptide alone yields predominantly sidechain condensation products with little stereoselectivity. Furthermore, the templating reaction is stable over a wide range of pH (5.6–8.6), salt concentration (0–4 M NaCl), and temperature (25–90 °C), making the amyloid an attractive model for a prebiotic peptide replicating system.

α‐Synuclein (α‐Syn) aggregation is associated with Parkinson's disease (PD) pathogenesis. In PD, the role of oligomers versus fibrils in neuronal cell death is debatable, but recent studies suggest oligomers are a proximate neurotoxin. Herein, we show that soluble α‐Syn monomers undergo a transformation from a solution to a gel state on incubation at high concentration. Detailed characterization of the gel showed the coexistence of monomers, oligomers, and short fibrils. In vitro, the gel was highly cytotoxic to human neuroblastoma cells. The individual constituents of the gel are short‐lived species but toxic to the cells. They comprise a structurally heterogeneous population of α‐helical and β‐sheet‐rich oligomers and short fibrils with the cross‐β motif. Given the recent evidence of the gel‐like state of the protein associated with neurodegenerative diseases, the gel state of α‐Syn in this study represents a mechanistic and structural model for the in vivo toxicity of α‐Syn in PD.

Feature selection in breast cancer disease important and risky task for further analysis. Breast cancer is the second leading reason for death among the women. Cancer starts from breast and spread to other part of the body. People are unable to identify their disease before it become dangerous. It can be cured if the disease identified at early stage. Accurate classification of benign tumours can avoid patients undergoing unnecessary treatments. Data Analytics and machine learning methods provides framework for prognostic studies by errorless classification of data instances into relevant based on the cancer severity. In this study we have purposed a prediction model by combining artificial intelligent based learning technique with multivariate statistical method. For automation of the diagnosis process data mining plays an significant role. The data sets available in different repositories are noisy in nature. This study suggests a hybrid feature selection method to be used with PCA (Principal Component Analysis) and Artificial Neural Network (ANN). Preprocessing of data and extracting the most relevant features done by PCA. The proposed algorithm is tested by applying it on Wisconsin Breast Cancer Dataset from UCI Repository of Machine Learning Databases. In classification phase 10 fold cross validation was used. The suggested algorithm was measured against different classifier algorithms on the same database. The evaluation results of the algorithm proposed have achieved better accuracy with sensitivity and F measure comparison with others and by enhancing this concept we can provide a future scope to produce sophisticated learning models for diagnosis.

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Abstractα‐Synuclein (α‐Syn) aggregation is associated with Parkinson's disease (PD) pathogenesis. In PD, the role of oligomers versus fibrils in neuronal cell death is debatable, but recent studies suggest oligomers are a proximate neurotoxin. Herein, we show that soluble α‐Syn monomers undergo a transformation from a solution to a gel state on incubation at high concentration. Detailed characterization of the gel showed the coexistence of monomers, oligomers, and short fibrils. In vitro, the gel was highly cytotoxic to human neuroblastoma cells. The individual constituents of the gel are short‐lived species but toxic to the cells. They comprise a structurally heterogeneous population of α‐helical and β‐sheet‐rich oligomers and short fibrils with the cross‐β motif. Given the recent evidence of the gel‐like state of the protein associated with neurodegenerative diseases, the gel state of α‐Syn in this study represents a mechanistic and structural model for the in vivo toxicity of α‐Syn in PD.