Signal transduction mechanisms in Caulobacter crescentus development and cell cycle control

The life cycle of the aquatic bacterium Caulobacter crescentus includes an asymmetric cell division and an obligate cell differentiation. Each cell division gives rise to a motile but replication inert swarmer cell and a sessile, replication competent stalked cell. While the stalked progeny immediately reinitiates DNA replication and cell division, the swarmer cell remains motile and chemotactically active for a constant period of the cell cycle before it differentiates into a stalked cell. During this process, the cell looses motility by ejecting the flagellum, synthesizes a stalk and eventually initiates chromosome replication and cell division. The link of morphogenic transitions to the replicative cycle of Caulobacter implies that the developmental programs which determine asymmetry and cell differentiation must be tightly connected with cell cycle control. This has been confirmed by the recent identification of signal transduction mechanisms, which are involved in temporal and spatial control of both development and cell cycle. Interestingly, the cell has recruited two-component signal transduction systems for this internal control, a family of regulatory proteins which usually are involved in the information transfer between the environment and the inside of a cell. The response regulator protein CtrA controls several key cell cycle events like the initiation of DNA replication, DNA methylation, cell division, and flagellar biogenesis. The activity of this master regulator is subject to complex temporal and spatial control during the C. crescentus cell cycle, including regulated transcription, phosphorylation and degradation. Three membrane bound sensor kinases have been proposed to control the phosphorylation status of CtrA. Two of these, CckA and DivJ, exhibit specific subcellular localization and, in the case of CckA, dynamic rearrangement in the course of the cell cycle. These findings support the idea that the developmental program of C. crescentus is controlled at least in part by localized cues that act as checkpoints for the control of morphological changes and cell cycle progressio

PENGGUNAAN MEDIA POSTER UNTUK MENINGKATKAN BERPIKIR KRITIS SISWA DALAM PEMBELAJARAN PENDIDIKAN KEWARGANEGARAAN (Studi Deskriptif Analitis di SMA Negeri 15 Bandung)

Pendidikan Kewarganegaraan sebagai suatu mata pelajaran di persekolahan yang masih terkesan sebagai mata pelajaran yang kurang menarik, kurang variatif serta teacher centered. Hal ini disebabkan karena masih terdapat guru Pendidikan Kewarganegaraan yang kurang variatif dalam hal media pembelajaran, sehingga kurangnya motivasi belajar siswa yang berakibat pada rendahnya keterampilan berpikir kritis siswa. Berdasarkan latar belakang hal tersebut, peneliti mencoba meneliti tentang penggunaan media poster sebagai salah satu media pembelajaran yang dapat meningkatkan berpikir kritis siswa sehingga melalui media poster diharapkan siswa dapat termotivasi dalam pembelajaran Pendidikan Kewarganegaraan. Pendekatan yang digunakan dalam penelitian ini adalah pendekatan kualitatif, dengan menggunakan metode studi deskriptif. Pengumpulan data dalam bentuk wawancara, observasi, dan studi dokumentasi. Hasil penelitian menunjukkan bahwa dalam merencanakan pembelajaran Pendidikan Kewarganegaraan dengan menggunakan media poster terlebih dahulu membuat rencana pelaksanaan pembelajaran yang terintegrasi dari silabus dan kurikulum yang kemudian divisualisasikan secara manual maupun memanfaatkan software yang tersedia dalam komputer. Dalam pelaksanaan pembelajaran Pendidikan Kewarganegaraan guru menggunakan media poster yang disesuaikan dengan metode pembelajaran, dalam pelaksanaan pembelajarannya pun memperlihatkan aktifitas siswa dan guru menggunakan media poster menjadikan suasana kelas lebih aktif dan kritis dalam pembelajaran. Respon siswa dalam pembelajaran media poster ditunjukkan dengan keberanian mengemukakan pendapat dan mengajukan pertanyaan disertai alasan logis, analisis pemecahan permasalahan yang ada, serta perkembangan mengevaluasi pembelajaran. Kendala yang muncul berkenaan dengan proses memvisualisasikan materi ke dalam media poster yang membutuhkan waktu dan keterampilan khusus. Upaya yang dilakukan yakni meningkatkan dan mengoptimalkan keterampilan guru dalam pembuatan pembelajaran media poster. Maka dapat disimpulkan bahwa media poster mampu memberikan kontribusi terhadap peningkatan berpikir kritis siswa dalam pembelajaran Pendidikan Kewarganegaraan. ---------- Citizenship education as a subject in the school which still impressed as subjects that are less attractive, less variable as well as teacher centered. This is because there is still a lack of citizenship education teachers vary markedly in terms of learning media, so the lack of motivation of student learning that result in a lack of critical thinking skills of students. Based on this background, researchers tried researching on the use of the media the poster as one of learning media that can improve critical thinking so students through the medium of the poster is expected of students can be motivated in learning of citizenship education. The approach used in this study is a qualitative approach, using the methods of descriptive studies. The collection of data in the form of interviews, observation, and study the documentation. The results showed that in the citizenship education learning plan using the media poster first create implementation plan integrated learning of the syllabus and curriculum that are then visualized by manually or take advantage of available software in the computer. In the implementation of citizenship education teachers use learning media posters that are tailored to the learning methods, in the implementation of any lesson that shows the activity of students and teachers using media poster makes the atmosphere more active and critical class in learning. Student response in learning media poster shown boldness suggested and ask questions with logical reason, analysis of solving existing problems, as well as the development of evaluating learning. Obstacles arise with regard to the process of visualizing material into the media poster which takes time and specialized skills. Efforts are being made to improve and optimize the skills of teachers in making learning media posters. Then it can be inferred that the media poster is able to contribute to the improvement of students ' critical thinking in learning of citizenship education

HUBUNGAN PENGGUNAAN APLIKASI DUOLINGO SEBAGAI MEDIA PEMBELAJARAN DENGAN KEPERCAYAAN DIRI BERBICARA BAHASA INGGRIS

Untuk bisa bersaing di dunia global diperlukan kemampuan berbicara bahasa Inggris. Hal tersebut harus didukung dengan kepercayaan diri yang dimiliki oleh siswa. Dengan perkembangan teknologi, semakin mempermudah siswa untuk melatih kepercayaan diri dalam berbicara bahasa Inggris. Salah satu aplikasi yang dapat digunakan adalah Duolingo. Aplikasi ini dapat digunakan siswa sebagai alternatif media belajar untuk melatih kepercayaan diri dalam berbicara bahasa Inggris. Penelitian ini bertujuan untuk menjawab rumusan masalah penelitian secara umum, “apakah terdapat hubungan yang signifikan antara penggunaan aplikasi Duolingo sebagai media pembelajaran dengan kepercayaan diri berbicara bahasa Inggris?”. Secara lebih khusus rumusan masalah terdiri dari “(1) Apakah terdapat hubungan yang signifikan antara penggunaan aplikasi Duolingo sebagai media pembelajaran dengan kepercayaan diri berbicara bahasa Inggris pada aspek keyakinan pada diri sendiri ?; (2) Apakah terdapat hubungan yang positif antara penggunaan aplikasi Duolingo sebagai media pembelajaran dengan kepercayaan diri berbicara bahasa Inggris pada aspek berani berbicara ?; (3) Apakah terdapat hubungan yang positif antara penggunaan aplikasi Duolingo sebagai media pembelajaran dengan kepercayaan diri berbicara bahasa Inggris pada aspek rasa positif diri ?. Penelitian ini menggunakan metode penelitian korelasional dengan pendekatan kuantitatif. Instrumen yang digunakan adalah angket. Teknik sampling yang digunakan adalah teknik random sampling dengan jumlah sampel penelitian sebanyak 30 orang. Berdasarkan kesimpulan umum dalam penelitian ini, menunjukkan bahwa terdapat hubungan yang positif dan signifikan antara penggunaan aplikasi Duolingo sebagai media pembelajaran dengan kepercayaan diri berbicara bahasa Inggris.;---In order to compete in a global world, the ability in speaking English is very essential. Thus, this matter should be supported by students’ self-confidence. With the development of technology, it is easy for the student to train their confidence in speaking English. One of the applications that can be used by the students is Duolingo. This application can be used by student as an alternative instructional media to train their confidence in speaking English. This study aims at answering the following research question, "Is there any positive and significant relationship between the use of Duolingo application as an instructional media with the confidence in speaking English?" . In details, the research questions are formulated as follows, (1) "Is there any positive and significant relationship between the use of Duolingo application as an instructional media with the confidence in speaking English in terms of self-confidence?; (2) "Is there any positive and significant relationship between the use of Duolingo application as an instructional media with the confidence in speaking English in terms of the bravery in speaking?; (3) "Is there any positive and significant relationship between the use of Duolingo application as an instructional media with the confidence in speaking English in terms of a positive sense of oneself. This study employed a correlational study with a quantitative approach. The instrument used was a questionnaire. The sampling technique used was the technique of random sampling, by involving 30 people as the samples of the study. Based on the general conclusion of this study, it is shown that there is a positive and significant relationship between the use of Duaolingo application as an instructional media with the confidence in speaking English, specifically in terms of self-confidence, bravery in speaking, and a positive sense of oneself

PENGARUH MODEL DIRECT INSTRUCTION DAN MODEL KOOPERATIF TERHADAP HASIL BELAJAR KETERAMPILAN PERMAINAN SEPAKBOLA

Pengajaran permaina sepakbola perlu berdampak pada bukan hanya meningkatkan kemampuan motorik tetapi juga perlu mengembangkan kemampuan pengetahuan dan kemampuan sosial siswa. Suatu penelitian eksperimen nonequivalent group pretest-postest design pada 50 orang siswa SMK Mutiara Bangsa Purwakarta telah dilakukan untuk melihat dampak pengajaran pada kebutuhan potensi siswa. Melalui instrumen penelitian games performance assesment instrument (GPAI) dan teknik analisis data uji t-test dengan taraf signifikansi α=0,05 diperoleh kesimpulan: 1). Pembelajaran direct instruction lebih mengutamakan pada prodak hasil belajar siswa dan lemah dalam proses belajar siswa, 2). Pembelajaran kooperatif mengutamakan proses hasil belajar siswa dan pada prodak hasil belajar siswa, 3). Pembelajaran kooperatif lebih menyenangkan daripada pembelajaran direct instruction dalam mengembangkan proses dan hasil belajar siswa. Pembelajaran yang mengkombinasikan keduanya akan lebih berdampak menyenangkan terhadap hasil belajar siswa.; Teaching the game of football should have an impact not only in improving motor skills, but also need to develop the ability of students' knowledge and social skills. An experimental study nonequivalent group pretest-posttest design to the 50 students of SMK Mutiara Bangsa Purwakarta has conducted to look at the impact of teaching on students' potential needs. Through research instrument games performance assessment instrument (GPAI) and data analysis techniques t-test with a significance level α = 0.05 was obtained conclusions: 1). Direct instruction learning more emphasis on student learning result and weak in the learning process of students, 2). Cooperative learning process prioritizing in the learning process result of students and on student learning result product, 3). Cooperative learning is more pleasure than learning direct instruction in developing processes and student learning result. Learning that combines both will have impact pleasure on result of learning student

Cyclic di-GMP: second messenger extraordinaire

Cyclic dinucleotides (CDNs) are highly versatile signalling molecules that control various important biological processes in bacteria. The best-studied example is cyclic di-GMP (c-di-GMP). Known since the late 1980s, it is now recognized as a near-ubiquitous second messenger that coordinates diverse aspects of bacterial growth and behaviour, including motility, virulence, biofilm formation and cell cycle progression. In this Review, we discuss important new insights that have been gained into the molecular principles of c-di-GMP synthesis and degradation, which are mediated by diguanylate cyclases and c-di-GMP-specific phosphodiesterases, respectively, and the cellular functions that are exerted by c-di-GMP-binding effectors and their diverse targets. Finally, we provide a short overview of the signalling versatility of other CDNs, including c-di-AMP and cGMP-AMP (cGAMP)

Cyclic di-GMP mediates a histidine kinase/phosphatase switch by noncovalent domain cross-linking

Histidine kinases are key components of regulatory networks in bacteria. Although many of these enzymes are bifunctional, mediating both phosphorylation and dephosphorylation of downstream targets, the molecular details of this central regulatory switch are unclear. We showed recently that the universal second messenger cyclic di-guanosine monophosphate (c-di-GMP) drives Caulobacter crescentus cell cycle progression by forcing the cell cycle kinase CckA from its default kinase into phosphatase mode. We use a combination of structure determination, modeling, and functional analysis to demonstrate that c-di-GMP reciprocally regulates the two antagonistic CckA activities through noncovalent cross-linking of the catalytic domain with the dimerization histidine phosphotransfer (DHp) domain. We demonstrate that both c-di-GMP and ADP (adenosine diphosphate) promote phosphatase activity and propose that c-di-GMP stabilizes the ADP-bound quaternary structure, which allows the receiver domain to access the dimeric DHp stem for dephosphorylation. In silico analyses predict that c-di-GMP control is widespread among bacterial histidine kinases, arguing that it can replace or modulate canonical transmembrane signaling

Dampak Program Gerakan Penerapan Pengelolaan Tanaman Terpadu (Gp-ptt) terhadap Tingkat Penerapan Teknologi Ptt pada USAhatani Jagung (Zea Mays L.) (Studi Kasus Dikelompok Tani Sangkan Hurip Desa Tanjungsari Kecamatan Rajadesa Kabupaten Ciamis)

Penelitian ini bertujuan untuk mengetahui : (1) Tingkat Penerapan Teknologi PTT sebelum dan sesudah petani mengikuti program GP-PTT ; (2) Dampak Program GP-PTT Terhadap Tingkat Penerapan Teknologi PTT Pada Usahatani Jagung (Zea mays L.) Jenis penelitian yang digunakan dalam penelitian ini adalah studi kasus di Kelompok Tani Sangkan Hurip Desa Tanjungsari Kecamatan Rajadesa Kabupaten Ciamis. Analisis data untuk mengetahui penerapan teknologi PTT sebelum dan sesudah petani mengikuti Program GP-PTT dianalisis secara deskriptif kualitatif, sedangkan untuk mengetahui Dampak Program GP-PTTTerhadap Tingkat Penerapan Teknologi PTT pada Usahatani Jagung dianalisis menggunakan pendekatan statitiska non parametrik yaitu uji tanda (sign test).Hasil penelitian menunjukkan bahwa : (1) Tingkat Penerapan Teknologi PTT sebelum petani mengikuti program GP-PTT sebanyak 17 orang (42,50) termasuk kategori sedang, sedangkan setelah petani mengikuti Program GP-PTT sebanyak 35 orang (87,50 % termasuk kategori tinggi;(2) Program GP-PTT mempunyai dampak positif yang nyata terhadap penerapan teknologi PTT pada USAhatani jagung di Desa Tanjungsari Kecamatan Rajadesa Kabupaten Ciamis

Sistema CBR para presentación de entrenamientos físicos personalizados en Internet

El proyecto ha consistido en el desarrollo de un sistema experto que asesora a los usuarios sobre entrenamientos físicos personalizados que resulten adecuados para cada condición física y cada objetivo de entrenamiento. El sistema hace uso de razonamiento basado en casos (Case Based Reasoning), siendo el dominio de conocimiento el entrenamiento médico-deportivo. Los casos describen tanto las características de los usuarios, como los entrenamientos que les corresponden. Los entrenamientos completos están formados secuenciando apropiadamente unidades de entrenamiento individuales. Los usuarios acceden al sistema por medio de una interfaz Web que permite tanto consultar la realización de ejercicios individuales como la obtención de un entrenamiento adaptado. La presentación que se muestra a los usuarios incluye, además de la explicación de cada unidad de entrenamiento, modelos que ejemplarizan las distintas posiciones que debe adoptar el cuerpo para ejecutar un ejercicio correctamente. Esos modelos consisten en representaciones humanoides creadas con programas de diseño gráfico de 2D y 3D. [ABSTRACT] The aim of this project was to develop an expert system that advises the users on the customized physical training that suits best each physical condition as well as training goals. The systems works with case-based reasoning (CBR) and the knowledge used is of the medical - sports training domain. The cases describe the user’s characteristics and the advised training programs, which are created by sequencing individual training units in an appropriate way. The users access the system via a web interface that allows them to consult how a specific exercise has to be executed as well as to request a training program generated to suit their individual needs. The presentation includes an explanation of each training unit and graphic models that visualize and exemplify the different positions the body has to adopt to perform the exercise correctly. These models are humanoid representations created with software for the design 2D and 3D graphics