Judul: Antibacterial activity of Bombyx mori and Samia cynthia ricini sericin proteins against Escherichia coli and Staphylococcus aureus
Abstrak: This study was designed to investigate the antibacterial properties of the sericin protein Bombyx mori and Samia cynthia ricini against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus strains. Sericin protein was extracted from the cocoons of B. mori races A, B, C, D, F1-1, F1,2 and S. ricini from Indonesia using a degumming process. Afterwards, the extract sericin protein were evaluated as antimicrobial such as Kirby Breuer disc diffusion, spectrometer measurement in decreasing OD value, and imaging Scanning Electron Microscope (SEM). The tests revealed that sericin protein from B. mori was more capable of inhibiting bacteria S. aureus than E. coli, whereas sericin protein from S. ricini was capable of strongly inhibiting both S. aureus and E. coli bacteria. The sericin proteins of B. mori and S. ricini were found to reduce the number of S. aureus and E. coli bacteria as the OD value decreased at a concentration of 9%. According to SEM imaging, sericin B. mori and S. ricini proteins caused changes in cell morphology in S. aureus and E. coli bacteria, resulting in bacterial cell function disruption and death. Sericin protein B. mori and S. ricini were able to against bacteria S. aureus than E. coli. Therefore, sericin protein is a potential to be antibacterial, particularly against Gram-positive strain S. aureus.
Keyword: antibakteri, Bombyx mori, Samia cynthia ricini, serisin

Judul: Antibacterial activity of Bombyx mori and Samia cynthia ricini sericin proteins against Escherichia coli and Staphylococcus aureus
Abstrak: Protein serisin dalam industri sutra tekstil akan terbuang dan menjadi limbah. Oleh karena itu perlu adanya aplikasi dalam mengolah limbah serisin menjadi produk yang memiliki nilai tambah. Pada beberapa penelitian dilaporkan bahwa protein serisin memiliki sifat antimikroba. Tujuan penelitian ini adalah mempelajari lebih lanjut sifat antibakteri pada protein serisin B. mori dan S. ricini terhadap bakteri Gram negatif E. coli dan Gram positif strain S. aureus. Penelitian ini dibagi menjadi 2 tahap. Tahap pertama yaitu proses analisis protein dengan metode Lowry dan SDS Page. Tahap kedua yaitu pengujian antibakteri yang terdiri dari uji zona bening Kirby Bauer Disc Diffusion, Penurunan nilai ∆OD (Optical Density) pada konsentrasi berbeda dan Pencitraan SEM. Hasil analisis protein didapatkan nilai persentase protein serisin ulat sutra murbei B. mori sebesar 24-38% dan ulat sutra non-murbei S. ricini didapatkan persentase protein serisin sebesar 23,58%. Hal ini dikarenakan pada S. ricini terdapat sekuens poli-Ala hidrofobik yang mempengaruhi kuantitas protein serisin ulat sutra. Hasil elektroforesis SDS- PAGE menunjukkan bahwa protein serisin B. mori dan S. ricini memiliki bobot molekul berkisar 15-93 kDa yang termasuk kategori bobot molekul berukuran kecil. Hasil uji antibakteri menunjukkan bahwa protein serisin B. mori lebih mampu menghambat bakteri S. aureus dari pada E. coli, sedangkan protein serisin dari S. ricini mampu secara kuat menghambat bakteri S. aureus dan E. coli yang mengakibatkan gangguan fungsi sel bakteri hingga kematian. Kata kunci: antibakteri, Bombyx mori, Samia cynthia ricini, serisin., In the textile silk business, the sericin protein will be squandered. As a result, an application for turning sericin waste into goods with additional value is required. Several investigations have found that the protein sericin possesses antibacterial capabilities. The goal of this study was to look at the antibacterial capabilities of the sericin proteins B. mori and S. ricini against Gram positive strain S. aureus and Gram negative strains E. coli. This study is separated into two sections. The first stage is the protein analysis procedure, which employs the Lowry and SDS Page techniques. The second step of testing is antibacterial testing, which includes the Kirby Bauer Disc Diffusion clear zone test, a decrease in ∆OD (Optical Density) value at concentration, and SEM imaging. Protein analysis revealed that the proportion of sericin protein in mulberry silkworm B. mori was 24-38%, whereas the percentage of sericin protein in non- mulberry silkworm S. ricini was 23,58%. This was due to the presence of a hydrophobic poly-Ala sequence which affected the amount of sericin protein. The findings of SDS-PAGE electrophoresis revealed that the proteins of sericin B. mori and S. ricini had molecular weights ranging from 15 to 93 kDa classifying them as small molecular weights. The antibacterial test findings revealed that sericin B. mori protein inhibited S. aureus more than E. coli, but sericin protein from S. ricini substantially inhibited both S. aureus and E. coli bacteria, resulting in reduced cell function and even death. Keywords: antibacterial, Bombyx mori, Samia cynthia ricini, sericin.
Keyword: antibacterial, Bombyx mori, Samia cynthia ricini, sericin

Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf