The putative hydrolase gene bhp from the balhimycin biosynthetic gene cluster has been cloned and overexpressed in Escherichia coli. The corresponding enzyme Bhp was purified to homogeneity by nickel-chelating chromatography and characterized. Although Bhp has sequence similarities to hydrolases with "haloperoxidase"/perhydrolase activity, it did not show any enzymatic activity with standard "haloperoxidase"/perhydrolase substrates (e.g., monochlorodimedone and phenol red), nonspecific esterase substrates (such as p-nitrophenyl acetate, p-nitrophenyl phosphate and S-thiophenyl acetate) or the model lactonase substrate dihydrocoumarin. However, Bhp could be shown to catalyse the hydrolysis of S-beta-hydroxytyrosyl-N-acetyl cysteamine thioester (beta-OH-Tyr-SNAC) with 15 times the efficiency of S-L-tyrosyl-N-acetyl cysteamine thioester (L-Tyr-SNAC). This is in agreement with the suggestion that Bhp is involved in balhimycin biosynthesis, during which it was supposed to catalyse the hydrolysis of beta-OH-Tyr-S-PCP (PCP=peptidyl carrier protein) to free beta-hydroxytyrosine (beta-OH-Tyr) and strongly suggests that Bhp is a thioesterase with high substrate specificity for PCP-bound beta-OH-Tyr and not a "haloperoxidase"/perhydrolase or nonspecific esterase.

The study was conducted to map the misconception pattern of chemistry prospective teachers who learned acid-base and argentometric titration. Further, it attempts to minimize misconception through a multiple representation model of learning chemistry with cognitive dissonance strategy. The first treatment was done on acid-base titration and the second treatment on argentometric titration materials. The multiple choice test with open reasons was administered to 30 undergraduate students. The finding shows that 28.6% students have the same pattern of misconception while learning in both of the courses. After the treatment, misconception decreased to 9.5% on the first treatment, and 9.4% on the second treatment. The model was found to be suitable to decrease the misconception, but could not change the misconception into "zero misconception", especially for microscopic and symbolic representations.

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Abstrak : Tujuan penelitian ini adalah untuk mengetahui pengaruh penggunaan model problem solving tipe Search, Solve, Create, and Share (SSCS) dan Cooperative Problem Solving (CPS) terhadap hasil belajar siswa dengan memperhatikan kemampuan matematisnya. Penelitian ini menggunakan metode eksperimen semu dan dilaksanakan dari bulan Desember 2012-Juni 2013. Populasi penelitian ini adalah siswa kelas XI IPA SMA N 1 Ngemplak Boyolali Tahun Pelajaran 2012/2013. Sampel diperoleh dengan teknik cluster random sampling yang terdiri dari dua kelas, XI IPA 1 dan XI IPA 3. Kelas XI IPA 1 diberi pembelajaran dengan model SSCS dan kelas XI IPA 3 diberi pembelajaran dengan model CPS. Data dikumpulkan dengan metode tes untuk prestasi belajar kognitif dan kemampuan matematis, angket untuk prestasi afektif, dan lembar observasi untuk psikomotor siswa. Hipotesis diuji menggunakan Anava dua jalan 2x2. Dari hasil analisis data disimpulkan bahawa: 1) Tidak ada pengaruh penggunaan model SSCS dan CPS terhadap prestasi belajar kognitif siswa, tetapi berpengaruh signifikan terhadap prestasi afektif dan psikomotor; 2) Ada pengaruh kemampuan matematis terhadap prestasi kognitif siswa, tetapi tidak ada pengaruhnya terhadap prestasi afektif dan psikomotor; 3) Ada interaksi antara model pembelajaran SSCS dan CPS dengan kemampuan matematis terhadap prestasi kognitif dan psikomotor siswa, tetapi tidak ada interaksinya terhadap prestasi afektif. Kata Kunci : problem solving, kemampuan matematis, prestasi belajarAbstract : The aims of this study were to determine the effect of the using problem solving type Search Solve Create and Share (SSCS) and Cooperative Problem Solving (CPS) models toward student's learning achievements by observe their mathematical ability. The method used in this research was quasi experimental method and it was conducted from December 2012 to June 2013. The population was the students in 11th Science Grade SMAN 1 Ngemplak Boyolali on Academic Year 2012/2013 Semester II. The samples were taken using cluster random sampling, consisted of two class XI IPA 1 and XI IPA 3. The learning method applied to XI IPA 1 was CPS and to XI IPA 3 was SSCS. The data were collected using tests for student's cognitive and mathematical ability, questioner for measuring affective, and observation sheet for assessing psychomotor. The hypotheses were tested using Anova (Analysis of Variance) two way 2x2 and Kruskal-Wallis one way analysis of variance method. From the data analysis, it's could be concluded that: 1) there was no effect of learning models towards student's cognitive, but there was an effect towards student's affective and psychomotor; 2) there was an effect mathematical ability towards student's cognitive, but there was no effect towards student's affective and psychomotor; 3) there was an interaction between learning models and mathematical ability toward student's cognitive and psychomotor, but there was no interaction toward student's psychomotor. Keywords: problem solving, mathematical ability, learning achievement PENDAHULUA...

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ABSTRAKPenelitian ini bertujuan untuk mengetahui aktivitas antibakteri senyawa C-4-metoksifenilkaliks [4]resorsinarena termodifikasi Hexadecyltrimethylammonium -Bromide (disingkat sebagai Resorsinarena-HDTMA-Br) terhadap bakteri Staphylococcus aureus dan bakteri Escherichia coli. Penelitian dilakukan dengan uji diameter zona hambat dengan metode difusi cakram kertas. Variasi konsentrasi sampel yang digunakan adalah 10%; 15%; 20%; 25%; dan 30% b/v. Dalam penelitian ini digunakan larutan Dimethyl sulfoxide (DMSO) (pelarut sampel) sebagai kontrol negatif dan Kloramfenikol sebagai kontrol positif. Hasil penelitian menunjukkan bahwa Resorsinarene-HDTMA-Br memiliki aktivitas antibakteri yang lebih tinggi dari pada C-4metoksifenilkaliks[4]resorsinarena (CMFKR) tak termodifikasi terhadap bakteri S. aureus. Baik CMFKR maupun Resorsinarena-HDTMA-Br tidak aktif terhadap E. coli. ABSTRACTThis study aims to determine the antibacterial activity of C-4-methoxyphenylcalix-[4]resorcinarene modified by Hexadecyltrimethylammonium-Bromide (Resorcinarene-HDTMA-Br) against Staphylococcus aureus and Escherichia coli bacteria. The study was conducted by testing the inhibition zone diameter with paper disc diffusion method. Variations in the concentration of the sample used were 10%; 15%; 20%; 25%; and 30% b/v. In this study, Dimethyl sulfoxide (DMSO) (sampel solvent) was used as a negative control and Chloramphenicol as a positive control. It was found that Resorsinarene-HDTMA-Br had higher antibacterial activity than the unmodified C-4methoxyphenylcalix[4]resorcinarene (CMFKR) against the S. aureus bacteria. Both CMFKR and Resorcinarene-HDTMA-Br are not active against E. coli.