 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Characterization of the Antibacterial Activity and Probiotic Properties of Lactic Acid Bacteria Isolated from Raw Fish and Nham-Plaa) ผู้เขียน: Suree Nanasombat, Saranya Phunpruch, Niracha Sriwong, Thitirut Jaichalad, Waragul Onnom, Supalak Odthon สื่อสิ่งพิมพ์:pdf AbstractIsolates of lactic acid bacteria from fish fillets and nham-plaa were screened to select the most suitable strains for the formulation of starter cultures with probiotic properties. Using an agar spot test, 30 of the 180 isolates that were tested inhibited at least one of four indicator strains; Staphylococcus aureus TISTR 118, Pediococcus acidilactici TISTR 051, Lactobacillus bulgaricus TISTR 415 and Listeria monocytogenes DMST 11256. Two bacterial isolates,13IS3 and 13IS4, from fish fillets were resistant to a low pH in lactic acid (pH 2.9-3.2) and in HCl (pH 2.2) and a high concentration of NaCl (6.0%) and bile salts (5.25%). These isolates were identified by morphological, biochemical and molecular analysis as Lactococcus lactis 13IS3 and Lactobacillus sakei 13IS4. The fermentation of nham-plaa model broth (NMB) by L. lactis 13IS3 seemed to be stimulated by 1.0% garlic extract and 0-1.5% NaCl at all temperatures of incubation. L. sakei 13IS4 fermented at a slower rate than L. lactis 13IS3, but fermented more rapidly in a 3.0%-garlic extract NMB with 0-1.5% NaCl at 30?C and in the same medium containing 1.0-1.5% NaCl at 35?C. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Study on the Acyl-Homoserine Lactone Production of a
Gram-Negative Bacterium Sphingomonas xenophaga
by Co-Cultivation with Variovorax paradoxus) ผู้เขียน:Saranya Phunpruch, Kei Kamino สื่อสิ่งพิมพ์:pdf AbstractAcyl-homoserine lactone is one of the signal molecules produced for the cell-to-cell communication
in Gram-negative bacteria. When bacteria reach the high cell density at a threshold level, they produce
acyl-homoserine lactone. Acyl-homoserine lactone can bind to the receptor and then induce the target
gene expressions resulting in the decrease of the bacterial populations. From the co-cultivation of
Sphingomonas xenophaga that can produce acyl-homoserine lactone and Variovorax paradoxus that can
utilize acyl-homoserine lactone as an energy source, it was found that the optimum conditions for cocultivation
both bacteria were LB medium and incubation temperature at 20?C. In addition, V. paradoxus
could degrade acyl-homoserine lactone produced from S. xenophaga as an energy source resulting in the
increase of the 2-fold higher growth rate. The slower death of S. xenophaga by co-cultivation is due to
the decrease of acyl-homoserine lactone level. |