Judul: Karakteristik Pertumbuhan Bakteri Asam Laktat Indigenous Susu Sapi Segar Sebagai Kandidat Bakteri Probiotik Dalam Saluran Pencernaan in vitro
Abstrak: Functional foods in the form of probiotic yogurt serves as a food that provides health effects, especially in the digestive tract. This probiotic yogurt can maintain the balance the intestinal microflora, especially between beneficial and pathogen bacterials. Terms of the probiotic bacteria concerned to lactic acid bacteria that were able to survive at the digestive tract. The purpose of this study was to investigate the characteristics of lactic acid bacteria indigenous cow’s milk as a candidate of probiotic bacteria. Resistancy of lactic acid bacteria through different pH conditions, in presence of bile salts or antibiotics, were tested in the media that was conditioned as human digestive tract (in vitro). Lactic acid bacteria resistance was seen through a comparison of the original population before the treatment and the population after treatment. The results of this study, bacteria L. acidophilus Y-01, B. longum Y-01 and L. bulgaricus S-01 can be used as candidates probiotic bacteria because it survived in a pH condition (pH 2, 2,5, 3,2 and 7,2), the condition of bile salts, and antibiotics. Although the population of S. thermophilus S-01 and L bulgaricus S-01 decreased after treatment, all four of these bacteria also produce antimicrobial evidenced by the clear zone that formed around the supernatant. This antimicrobial activity showed inhibition to the growth pathogenic bacteria (E. coli, S. Typhimurium, and S. aureus).
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Judul: Karakteristik Ketahanan Bakteri Asam Laktat Indigenous Dadiah Sebagai Kandidat Probiotik Pada Kondisi Saluran Pencernaan in vitro
Abstrak: Probiotic bacteria defined as living microorganisms which will confer health benefit to the host when administered in adequate amounts. The aims of this research were to study the potential of Lactobacillus plantarum D-01, Lactococcus lactis D-01, Bifidobacterium longum Y-01, and Lactobacillus acidophilius Y-01 as probiotic bacteria through its ability to survive in gastrointestinal conditions (acid conditions of stomach and the presence of bile salts in the small intestine), its resistance to antibiotics, and its antimicrobial properties against pathogen bacterias. This study initiated with assays of four tested Lactic Acid Bacterias for its ability to grow and survive in acid conditions and the presence of bile salts or antibiotics, also its antagonistic activities against indicator strains of pathogen bacterias (Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923 and Salmonella Thypimurium ATCC 14028). Result showed the ability of L. plantarum D-01, L. lactis D-01, B. longum Y-01 and L. acidophilus Y-01 to grow in acid conditions and tolerance at the presence of bile salts and antibiotics (t-test). Research found that difference species LABs tested influenced diameter of the inhibition zone against pathogen indicator bacterias (P<0.01). L. acidophilus Y-01 had the largest inhibition zone against S. Thypimurium ATCC 14028 and E. coli ATCC 25922, while B. longum Y-01 was able to produce the largest inhibition zone against S. aureus ATCC 25923 (P<0,05). Based on the characterization of four species LAB, it could be concluded that L. plantarum D-01, L. lactis D-01, B. longum Y-01, and L. acidophilius Y-01 can be used as probiotic.
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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