Time delay as a key to Apoptosis Induction in the p53 Network

A feedback mechanism that involves the proteins p53 and mdm2, induces cell death as a controled response to severe DNA damage. A minimal model for this mechanism demonstrates that the respone may be dynamic and connected with the time needed to translate the mdm2 protein. The response takes place if the dissociation constant k between p53 and mdm2 varies from its normal value. Although it is widely believed that it is an increase in k that triggers the response, we show that the experimental behaviour is better described by a decrease in the dissociation constant. The response is quite robust upon changes in the parameters of the system, as required by any control mechanism, except for few weak points, which could be connected with the onset of cancer

Meningkatkan Kemampuan Guru Sekolah Binaan Menyusun Evaluasi Belajar Akhir Semester Ganjil melalui Pemberian Tugas Diakhiri Workshop pada SD Negeri 025 Menaming

Prepare the final semester test results to measure the success of students in mastering basic competence indicators at the end of the semester, by looking at the results of teachers will know the weaknesses of students. To be able to compile a test that meets the requirements is quite difficult because preparing the test requires knowledge, skill and high accuracy. This research is descriptive qualitative research. This research was conducted in SD Negeri 25 Menaming with total teachers of 14 teachers. The purpose of this study is to describe the level of mastery of the ability of teachers in preparing the evaluation of learning (test) through the assignment of the workshop ended. The methods used in this study include test methods, observation methods, and interview methods. The application of the workshop in preparing the final semester test result is very effective. Attitude and ability of teachers of SD Negeri 25 Manaming after giving the assignment ended the workshop was satisfied, because through the assignment that ends the workshop can use the time so it is not delayed. Through the workshop can also improve the ability of teachers in preparing the test, it is seen in the first cycle activity average value 57 Tests are considered feasible if at least 75% of criteria can be met. Then the workshop cycle II, then a complete 10 people (78%), so that more skilled school teachers entirely make the problem in the future, then proceed to cycle III with workshops where teachers have made a matter of home for verification or study. So after being assessed in the workshop III cycle of this result is very satisfactory that complete 14 people with 100% percentage was able to arrange the final semester test results

Mapping of mutation-sensitive sites in protein-like chains

In this work we have studied, with the help of a simple on-lattice model, the distribution pattern of sites sensitive to point mutations ('hot' sites) in protein-like chains. It has been found that this pattern depends on the regularity of the matrix that rules the interaction between different kinds of residues. If the interaction matrix is dominated by the hydrophobic effect (Miyazawa Jernigan like matrix), this distribution is very simple - all the 'hot' sites can be found at the positions with maximum number of closest nearest neighbors (bulk). If random or nonlinear corrections are added to such an interaction matrix the distribution pattern changes. The rising of collective effects allows the 'hot' sites to be found in places with smaller number of nearest neighbors (surface) while the general trend of the 'hot' sites to fall into a bulk part of a conformation still holds.Comment: 15 pages, 6 figure

Oscillations and temporal signalling in cells

The development of new techniques to quantitatively measure gene expression in cells has shed light on a number of systems that display oscillations in protein concentration. Here we review the different mechanisms which can produce oscillations in gene expression or protein concentration, using a framework of simple mathematical models. We focus on three eukaryotic genetic regulatory networks which show "ultradian" oscillations, with time period of the order of hours, and involve, respectively, proteins important for development (Hes1), apoptosis (p53) and immune response (NFkB). We argue that underlying all three is a common design consisting of a negative feedback loop with time delay which is responsible for the oscillatory behaviour

Folding and Misfolding of Designed Heteropolymer Chains with Mutations

We study the impact of mutations (changes in amino acid sequence) on the thermodynamics of simple protein-like heteropolymers consisting of N monomers, representing the amino acid sequence. The sequence is designed to fold into its native conformation on a cubic lattice. It is found that quite a large fraction, between one half and one third of the substitutions, which we call 'cold errors', make important contributions to the dynamics of the folding process, increasing folding times typically by a factor of two, the altered chain still folding into the native structure. Few mutations ('hot errors'), have quite dramatic effects, leading to protein misfolding. Our analysis reveals that mutations affect primarily the energetics of the native conformation and to a much lesser extent the ensemble of unfolded conformations, corroborating the utility of the ``energy gap'' concept for the analysis of folding properties of protein-like heteropolymers.Comment: 12 pages, Latex (Revtex

Hambatan Dinas Pendidikan Provinsi Bengkulu dalam Pengintegrasian Pengelolaan SMA dan Smk

The purpose of writing the article is to describe the barriers and solutions in the management of high school and vocational integration into the province of Bengkulu. The method used is descriptive qualitative analysis. The subjects used in are: Head, Head, Head of Sector Dikmen, and Principal of SMA and SMK. The tools used in the collection of data is by using interviews, documentation, and observation. The results of the study are as follows: Readiness Education Department of Bengkulu province in carrying out the implementation of actional rule No. 23 of 2014, is now being preparing for the transition of authority from the district / city to the provinces to collect data on the number of high school teachers and vocational school, the school\u27s assets, the number of supervisors, as well as matters more about the switch. This data collection has been conducted from February to April 2016 yesterday, then on October 3, 2016 will be the handover of district / city government to the provinces

Role of bulk and of interface contacts in the behaviour of model dimeric proteins

Some dimeric proteins first fold and then dimerize (three--state dimers) while others first dimerize and then fold (two--state dimers). Within the framework of a minimal lattice model, we can distinguish between sequences obeying to one or to the other mechanism on the basis of the partition of the ground state energy between bulk than for interface contacts. The topology of contacts is very different for the bulk than for the interface: while the bulk displays a rich network of interactions, the dimer interface is built up a set of essentially independent contacts. Consequently, the two sets of interactions play very different roles both in the the folding and in the evolutionary history of the protein. Three--state dimers, where a large fraction of the energy is concentrated in few contacts buried in the bulk, and where the relative contact energy of interface contacts is considerably smaller than that associated with bulk contacts, fold according to a hierarchycal pathway controlled by local elementary structures, as also happens in the folding of single--domain monomeric proteins. On the other hand, two--state dimers display a relative contact energy of interface contacts which is larger than the corresponding quantity associated with the bulk. In this case, the assembly of the interface stabilizes the system and lead the two chains to fold. The specific properties of three--state dimers acquired through evolution are expected to be more robust than those of two--state dimers, a fact which has consequences on proteins connected with viral diseases