Judul: Literature Review of Isolation, Confirmation, Occurrence of Toxigenic Genes, and The Prevalence of Bacillus cereus in Rice
Abstrak: Bacillus cereus merupakan salah satu bakteri patogen penyebab keracunan pangan yang dihubungkan dengan nasi. Keracunan pangan akibat Bacillus cereus dapat disebabkan oleh enterotoksin dan cereulida. Kajian ini bertujuan untuk mereview metode isolasi dan konfirmasi Bacillus cereus, mengetahui gen penyandi enteretoksin dan cereulida pada Bacillus cereus, dan mengetahui prevalensi Bacillus cereus pada produk nasi berdasarkan sumber pustaka ilmiah. Metode pengumpulan sumber pustaka dilakukan dengan mengunduh beberapa pustaka dari google scholar dengan mengetik kata kunci, yaitu “Bacillus cereus, cooked rice, polymerase chain reaction, biochemical test, prevalence, toxigenic, enterotoxin, cereulide”. Berdasarkan metode tersebut, ditemukan 75 pustaka metode uji, prevalensi, dan keanekaragaman gen penyandi toksin Bacillus cereus. Sebanyak 9 sumber pustaka dari jurnal internasional bereputasi yang dipublikasi dalam rentang tahun 2006-2021 digunakan sebagai data sekunder utama, sedangkan 66 pustaka lainnya digunakan sebagai data pendukung. Metode deteksi biokimia melibatkan beragam jenis uji seperti, pewarnaan Gram, reaksi terhadap kuning telur, katalase, reduksi nitrat, Voges Proskauer, motilitas, β-Hemolisis, indol, pertumbuhan anaerobik, penggunaan sitrat, koagulase, pertumbuhan rhizoid, fermentasi laktosa, fermentasi glukosa, dan hidrolisis berbagai substrat seperti pati kasein, tributirin, dan urea. Metode PCR dilakukan untuk mendeteksi gen penyandi 16S rRNA, enterotoksin maupun cerulida. Keberadaan gen penyandi enterotoksin pada B. cereusyang diisolasi dari nasi meliputi hblA, hblC, dan hblD dengan prevalensi 2.9-100%, nheA, nheB, nheC dengan prevalensi 38.2-100%, cytK dengan prevalensi 50.0-89.8%, entFM dengan prevalensi 76.5-100%, dan bceT memiliki prevalensi sebesar 51.0-55.5%. Sementara itu prevalensi ges ces penyandi toksin emetic adalah 0-14.7%. Berdasarkan kajian Pustaka yang digunakan prevalensi B. cereus pada nasi dari beberapa negara berada pada kisaran 20-82.5%., Bacillus cereus is one of the pathogenic bacteria that causes food poisoning associated with rice. Food poisoning due to Bacillus cereus can be caused by enterotoxins and cereulida. This study aims to review the isolation and confirmation method of Bacillus cereus, determine the genes encoding enteretoxin and cereulida in Bacillus cereus, and determine the prevalence of Bacillus cereus in rice products based on scientific literature sources. The method of collecting library resources is done by downloading several libraries from Google Scholar by typing keywords, namely "Bacillus cereus, cooked rice, polymerase chain reaction, biochemical test, prevalence, toxigenic, enterotoxin, cereulide". Based on this method, there were 75 libraries of test methods, prevalence, and diversity of genes encoding the toxin Bacillus cereus. A total of 9 sources of literature from reputable international journals published in the period 2006-2021 were used as primary secondary data, while the other 66 libraries were used as supporting data. The biochemical detection method involves various types of tests such as, Gram stain, reaction to egg yolk, catalase, nitrate reduction, Voges Proskauer, motility, -Hemolysis, indole, anaerobic growth, use of citrate, coagulase, rhizoid growth, lactose fermentation, glucose fermentation, and hydrolysis of various substrates such as casein starch, tributyrin, and urea. The PCR method was used to detect genes encoding 16S rRNA, enterotoxins and cerulides. The presence of enterotoxin-coding genes in B. cereus isolated from rice included hblA, hblC, and hblD with a prevalence of 2.9-100%, nheA, nheB, nheC with a prevalence of 38.2-100%, cytK with a prevalence of 50.0-89.8%, entFM with a prevalence of 76.5-100%. 100%, and bceT has a prevalence of
Keyword: Bacillus cereus, Biochemical, Prevalence, Polymerase chain reaction (PCR), Rice

Judul: Isolation and Characterization of Bacillus cereus from Fresh Vegetables
Abstrak: Sayuran merupakan komoditas yang memiliki kandungan gizi dan kadar air tinggi sehingga rentan ditumbuhi oleh mikroorganisme, salah satunya Bacillus cereus. B. cereus dapat menyebabkan pembusukan dan penyakit bawaan pangan dan merupakan patogen penyebab penyakit bawaan pangan kedua terbesar di Indonesia. Oleh karena itu, penelitian mengenai keberadaannya dalam berbagai produk perlu dilakukan. Penelitian ini bertujuan mengetahui keberadaan, konsentrasi, dan karakteristik B. cereus dalam sayuran segar, serta mengonfirmasi isolat yang diperoleh menggunakan API 50 CHB. Penelitian dibagi menjadi isolasi, karakterisasi, serta konfirmasi isolat B. cereus yang diperoleh. Sebanyak 20 sampel sayuran diambil dan diisolasi menggunakan mannitol-egg yolk-polymyxin (MYP) agar. Koloni terduga selanjutnya dikarakterisasi dengan pewarnaan Gram, spora, uji katalase, dan dikonfirmasi dengan perangkat API 50 CHB. Isolasi menghasilkan 45 isolat terduga B. cereus dari 20 sampel, dengan konsentrasi 1,55 – 3,61 log CFU/g. Urutan sampel dari yang mengandung B. cereus paling banyak adalah kangkung, kentang, wortel dan bawang, lalu buncis. Karakterisasi dengan pewarnaan dan katalase menunjukkan 35 dari 45 isolat memiliki karakteristik morfologi serupa dengan B. cereus. Dari 20 sampel sayuran, 19 sampel mengandung isolat dengan katakteristik morfologi B. cereus sehingga prevalensinya adalah 95%. Sebanyak 4 isolat dengan karakteristik B. cereus dikonfirmasi dengan API 50 CHB dan terkonfirmasi sebagai B. cereus dengan persentase 99,70 – 99,90%, sementara itu 3 isolat yang tidak memiliki karakteristik B. cereus juga terkonfirmasi sebagai spesies selain B. cereus. Hal ini menunjukkan pewarnaan Gram, spora, dan uji katalase dapat digunakan sebagai pra-konfirmasi B. cereus dari pangan., Vegetables are commodities containing high nutrient and moisture content, so they are prone to microbial growth, such as Bacillus cereus. B. cereus in foods can cause spoilage and foodborne illnesses and was the second most pathogens to cause foodborne illnesses in Indonesia, hence research on its occurrence in various products needs to be done. This study aimed to determine the occurrence, concentration, and characteristics of B. cereus in fresh vegetables, and to confirm the isolates using API 50 CHB. The research consisted of isolation, characterization, and confirmation using a rapid test kit. Twenty samples of vegetables was collected and presumptive B. cereus was isolated using mannitol-egg yolk-polymyxin (MYP) agar. The suspected colonies were characterized by Gram, spores staining, catalase test, and confirmed using API 50 CHB.We obtained 45 suspected B. cereus isolates from all 20 samples, with concentration of 1,55 – 3,61 log CFU/g. The order of samples containing the most B. cereus was water spinach, potatoes, carrots and onions, then snap beans. Characterization concluded that 35 out of 45 suspects were having morphology resembling B. cereus. Of the 20 vegetables, 19 were confirmed to contain isolates with B. cereus morphology hence the prevalence of 95%. A total of 4 isolates with B. cereus morphology were confirmed as B. cereus 99,70 – 99,90% using API 50 CHB and 3 isolates without B. cereus morphology were confirmed as non B. cereus. The result indicates that Gram, spore staining and catalase test can be use for pre confirmation of B. cereus in foods.
Keyword: Bacillus cereus, biochemical confirmation, characterization, isolasi, isolation, karakterisasi, konfirmasi biokimiawi, sayuran, vegetables

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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