Judul: Studi sifat penempelan bakteri asam laktat asal air susu ibu
Abstrak: Probiotics are live microorganism that will exert beneficial effect to the host when ingested in sufficient amounts. The ability to adhere to intestinal epithelial cells is a prerequisite for probiotic action. The aim of this study was to identify the adherence properties of nine lactic acid bacteria isolated from breast milk which are potential as probiotic (L. rhamnosus A15, Lactobacillus A27, L. rhamnosus A29, L. rhamnosus R14, L. rhamnosus R21, L. rhamnosus R23, L. rhamnosus R26, L. rhamnosus B10, L. rhamnosus B13, dan L. rhamnosus B16). This study was conducted in three stages i.e. (1) the evaluation of adherence method on mucus of broiler and rat intestine (2) the evaluation of adherence properties that consist of hydrophobicity, autoaggregation, adhesion to rat intestinal cells, and adhesion to the surface of rat intestine and (3) the competition of adhesion between LAB and EPEC which included competition, exclusion, displacement, and observation of the bacteria adherence on the surface of rat intestine used SEM. The use of rat intestine gave better result in showing the adhesion ability of LAB tested than mucus of broiler. The exposure of rat intestine in suspension of LAB raised the total number of LAB which indicated the attachment of LAB isolates while reducing the total number of E. coli which indicated competition between LAB and indigenous E. coli on the surface of rat intestine. All of nine LAB isolates tested have low autoaggregation ability due to their hydrophobicity. There were only three LAB isolates that adhered to rat intestinal cells, they were A27, B16, and R23. However, all LAB isolates adhered to the surface of rat intestine. The most adhesive LAB was A27 followed by B16, R14, and R23. The degree of adherence of LAB was strain specific and affected by the type of adherence medium. The competition test showed that the LAB isolates tested were able to compete with EPEC. The adhesion of the LAB isolates affected by the number of LAB, the higher the number of LAB the higher the number of adhering bacteria. The exclusion and displacement test showed that the LAB isolates tested were likely able to attach well on the surface of rat intestine. R23 isolate was not able to be excluded by EPEC while B16 isolate was slightly excluded. Both LAB isolates were not able to displace EPEC. The observation of adherence using SEM showed bacilliform of bacteria on the surface of rat intestine that have been incubated with LAB R14, R23, B16, and A27.
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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: 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