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Psychobiotics are defined as the organisms that can provide the mental health benefit. The possible mechanism of psychobiotics is manipulation of neurotransmitter production and neurotransmitter production by the microbes. The lactobacillus group has been reported for the potential of neurotransmitter production, especially g-aminobutyric acid (GABA) which is an important inhibitory neurotransmitter. Therefore, GABA can be used for relaxation and applied in various psychiatric disorders. The aim of this study was determination of lactic acid bacterial isolates from Pak Sian Dong in Thailand for GABA producing ability. The results found that there were 3 isolates, SF66, SF80 and SF82, which revealed the ability to produce glutamic acid decarboxylase (GAD) enzyme. The GABA were detected by thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC) in the bacterial culture containing 3% monosodium glutamate. The survival in gastrointestinal synthetic condition found that only SF66 isolate showed the authentic percentage of survival then this isolate was selected. From the identification, the isolate was identified as Lactiplantibacillus pentosus and was designated as L. pentosus SF66 which exhibited with the potential for further investigation and development to be psychobiotics.

The interesting application of bile salt hydrolase enzyme is reduction of cholesterol in serum and amelioration lipid profile. While uricase enzyme can be applied to convert insoluble uric acid to be soluble form and excrete from the body. Probiotics are living organisms with generally know that they can provide beneficial effects to their host. Several reports show that probiotic bacteria with bile salt hydrolase and uricase can improve hypercholesterolemia and hyperuricemia patient. The novel isolate of Lactobacillus from Pak Sian Dong in this study is identified as L. brevis SF121 and probably use as probiotic bacteria in the future. However, this isolate still need further experiments to investigate and improve properties of probiotics. Moreover, this finding suggests that Pak Sian Dong or fermented spider plant can be designated as a good source for probiotic screening and also defines as health-promoting diet.

Bile salt hydrolase is an enzyme from bacteria that can hydrolyze bile acid to be insoluble form and this event lead to reducing of cholesterol level in serum. A new strain of lactic acid bacteria, which was isolated from fermented spider plant in local market of Thailand, showed ability to produce bile salt hydrolase and has potential to be probiotic bacteria with good colonizing properties. The new strain was identified as Lactobacillus plantarum and gene that responsible for bile salt hydrolase production is located on plasmid. From the study could be suggested that novel strain of LAB possible to be further used as cholesterol lowering probiotic bacteria and fermented spider plant would be cheap price cholesterol lowering foods for people in local area.

Data on the distribution of free-living amoebae is still lacking especially in Southeast Asian region. The aquatic environment revealed a high occurrence of free-living amoebae (FLA) due to its suitable condition and availability of food source, which subsequently causes infection to humans. A total of 94 water samples consisted of both treated and untreated from Laos (31), Myanmar (42), and Singapore (21) were investigated for the presence of pathogenic FLA. Each water sample was filtered and cultured onto non-nutrient agar seeded with live suspension of Escherichia coli and incubated at room temperature. Morphological identification was conducted for both trophozoites and cysts via microscopic stains (Giemsa and immunofluorescence). The presence of Naegleria-like structures was the most frequently encountered in both treated and untreated water samples, followed by Acanthamoeba-like and Vermamoeba-like features. To identify the pathogenic isolates, species-specific primer sets were applied for molecular identification of Acanthamoeba, Naegleria, and Vermamoeba. The pathogenic species of Acanthamoeba lenticulata and A. triangularis were detected from untreated water samples, while Vermamoeba vermiformis was found in both treated and untreated water samples. Our results suggested that poor water quality as well as inadequate maintenance and treatment might be the cause of this alarming problem since chlorine disinfection is ineffective in eradicating these amoebas in treated water samples. Regular monitoring and examination of water qualities are necessary in order to control the growth, hence, further preventing the widespread of FLA infections among the public.

[This corrects the article DOI: 10.1371/journal.pone.0169448.].