Judul: Whole-Genome Sequence Analysis and Probiotic Characteristics of a Lactococcus lactis subsp. lactis strain Lac3 Isolated from Traditional Fermented Buffalo Milk (Dadih)
Abstrak: The intention to conduct the current study was associated with the insufficiency of data availability on the whole-genome sequencing and in vitro characterization of probiotic potential of L. lactis subsp. lactis strain Lac3 in order to select the L. lactis subsp. lactis Lac3 as the future probiotic candidate. Most L. lactis has been included in the GRAS (Generally Recognized As Safe) status by (FDA) (the United States Food and Drug Administration). L. lactis has been considered as a promising probiotic candidate that has the versatile applications in animal, animal feeds, pharmaceuticals, clinical and food industries. L. lactis has been used as the starter cultures in the fermentation of dairy products, like cheese, yoghurt, sauerkraut, as well as in clinical to treat diseases by preventing pathogenic infections from the host. Moreover, L. lactis proved to enrich the foods into vitamins and amino acids and prevent allergy, etc. However, the selection of suitable probiotic candidate should require the assessment of its ability of tolerance against stressful conditions, such as acid, salts, bile salt tolerance and adhesion properties either in the gastrointestinal transit or survival in the niche environments, as well as the safety analysis like antibiotic resistance, pathogenicity, virulency, hemolytic activity and biogenic amines production. Besides, probiotic candidate should be evaluated for its ability to produce antimicrobial compounds. By this reason, we aimed at carrying whole-genome sequence analysis and in vitro characterization of probiotic potential of a L. lactis subsp. lactis Lac3. The results of this study are indispensable to provide information on genome diversity, stability, molecular evolution, safety, and probiotic potential properties which are suitable for the selection of L. lactis subsp. lactis Lac3 as the future probiotic for industrial food exploitation and health. Illumina MiSeq Next-generation sequencer was used to produce the genome reads with the size of ~3.8Mb, each sequence had the length of 150bp, and with an estimated genome size approximately ~7.6Mb. Sequencing was processed by (Novogene Co., Ltd). The de novo assembly was conducted using Unicyler.v assembler algorithm integrated into the Pathosystems Resource Integration Center (PATRIC) platform, and produced 55 contigs. Genome annotation was added by prokaryotic genome annotation pipeline (PGAP) available in NCBI and Rapid Annotations under Subsystem Technology (RAST) online webserver. Specific genome features were annotated within the genome, including antibiotic resistance phenotypes (resistomes), mobilomes (prophages, insertion sequences (ISs), plasmid), virulence factors and CRISPR/Cas system. The specific annotation was done by using various online bioinformatic tools, such as Comprehensive Antibiotic resistance Database (CARD), Resistance Gene identifier (RGI), ResFinder 4.1, PlasmidFinder, PHASTER, VirulenceFinder 2.0 and Mobile genetic element (MGEsFinder). Furthermore, identification was done based on 16S rRNA by performing nucleotide BLAST analysis and scanning electron microscopy. Phylogenetic tree was generated by using MEGA-X, and sequences were aligned by using MUSCLE. The bootstrap was inferred from 1000 replications, and taxonomic connection was inferred by using Neighbor-joining method. Besides, in vitro characterization of L. lactis subsp. lactis Lac3 was conducted to assess the probiotic characteristics of L. lactis subsp. lactis Lac3, including tolerance to acid, bile salts, NaCl, auto-aggregation (adhesion properties) and antibiotic resistance. The genome annotation predicted L. lactis
Keyword: Genome sequence, in vitro characterization, pathogenicity, probiotic potential, safety

Judul: Characterization of indigenous lactic acid bacteria from beef as probiotic and identification by 16s rRNA gene sequencing
Abstrak: Functional foods are foods that have health promising benefit over and above their basic nutritional value. Probiotics are included as component of functional foods. Probiotics are live microorganisms which when administered in adequate amounts confer a health benefit on the host. The research was aimed to characterize the probiotic properties and to identify indigenous lactic acid bacteria (LAB) isolated from fresh beef derived from traditional market around Bogor, West Java, Indonesia. The twenty eight LAB isolates showed different ability to survive under simulated gastrointestinal conditions. Only 10 isolates could survive well at pH 2.0 (survival rate over than 50%) and the population increased at pH 2.5, 3.2 and 7.2. The ten LAB isolates (strain 2B4, 1B1, 1A5, 2C2, 2D1, 2B2, 1C4, 2B1, 1A32 and 2C12) could survive well at 0.5% bile salt, showed antibacterial activities and good coagregation capabilities against the tested pathogenic bacteria (Escherichia coli ATCC 25922, Salmonella Typhimurium ATCC 14028, Enteropathogenic Escherichia coli/EPEC, and Staphylococcus aureus ATCC 25923) and could adhere to intestinal surface by in vitro analysis. The 16S rRNA gene could be amplified by PCR (Polymerase Chain Reaction) to get single band with designed primer. Identification by 16S rRNA gene sequencing of 20 isolates showed that 11 isolates were identified as Lactobacillus plantarum, 6 isolates as Lactobacillus acidophilus, 2 isolates as Pediococcus pentosaceous and 1 isolate as Enterococcus faecium. The ten LAB isolates were proven to be probiotic candidates, which consist of 7 isolates of Lactobacillus plantarum (strain 1B1, 1A5, 2D1, 2B2, 1C4, 2B1, 2C12) and 3 isolates of Lactobacillus acidophilus (strain 2B4, 2C2, 1A32). Lactobacillus plantarum 2C12 and Lactobacillus acidophilus 2B4 were further evaluated to prevent diarrheae caused by EPEC. Albino rats (Rattus norvegicus) were daily orally administered by 108 cfu/ml of both probiotics without or simultaneously infected with EPEC (106 cfu/ml). Negative control was not infected by probiotic and EPEC while positive control was challenged with EPEC alone. It was observed that rats administered by L. plantarum 2C12 and L. acidophilus 2B4 which were challenged with EPEC had better performances when compared with the positive control for daily weight gain, feed consumption and feed efficiency rate. Both probiotics could prevent diarrhea caused by EPEC by increasing total population of lactic acid bacteria 1 log cfu/cm2 on mucosa of cecum and 1 log cfu/g on content of cecum, reducing population of E.coli 1-2 log cfu/cm2 on mucosa of cecum and 1 log cfu/g on cecum content also increasing 33.66-71.79 x 106 cell on lymphocytes. L. acidophilus 2B4 had better probiotic characteristics than L. plantarum 2C12, with specific health function to prevent diarrhea caused by EPEC.
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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