Objective: This study aims to characterise the lactic acid bacteria (LAB) isolated from local Malaysian fermented foods with oral probiotics properties. Design: The LAB strains isolated from Malaysian fermented foods, Lactobacillus brevis FT 6 and Lactobacillus plantarum FT 12, were assessed for their antimicrobial properties against Porphyromonas gingivalis ATCC 33277 via disc diffusion assay. Anti-biofilm properties were determined by treating the overnight P. gingivalis ATCC 33277 biofilm with different concentrations of LAB cell-free supernatant (LAB CFS). Quantification of biofilm was carried out by measuring the optical density of stained biofilm. The ability of L. brevis FT 6 and L. plantarum FT 12 to tolerate salivary amylase was also investigated. Acid production with different sugars was carried out by pH measurement and screening for potential antimicrobial organic acid by disc diffusion assay of neutralised probiotics CFS samples. In this study, L. rhamnosus ATCC 7469, a commercial strain was used to compare the efficacy of the isolated strain with the commercial strain. Results: Lactobacillus brevis FT 6 and L. plantarum FT 12 possess antimicrobial activity against P. gingivalis with inhibition diameters of more than 10 mm, and the results were comparable with L. rhamnosus ATCC 7469. The MIC and MBC assay results for all tested strains were recorded to be 25 µl/µl concentration. All LAB CFS reduced biofilm formation proportionally to the CFS concentration and tolerated salivary amylase with more than 50% viability. Overnight cultures of all lactic acid bacteria strains showed a pH reduction and neutralised CFS of all lactic acid bacteria strains did not show any inhibition towards P. gingivalis. Conclusions: These results indicate that the isolated probiotics have the potential as probiotics to be used as a supportive oral health treatment, especially against a periodontal pathogen, P. gingivalis.

The aim of this study was to isolate lactic acid bacteria (LAB) from fermented food, to determine its antibacterial activity, and to identify the LAB in order to select candidate probiotic strains for preventing caries. The probiotic strains were isolated from eight fermented food which are tapai ubi, tapai pulut, rebung, tauchu, kimchi, incalok, tempeh and tempoyak, taucu. Ten-fold serial dilutions of the fermented food samples were made in sterile peptone water before plating on de Man Rogosa and Sharpe (MRS) agar. The pure cultures were then randomly picked and biochemically identified. Then, the antibacterial activity of LAB against Streptococcus mutans was assessed by using the disk diffusion method. A total of 120 LAB were isolated from eight different fermented foods. The morphologies of the isolates were circular, convex, dull opaque white or translucent white. Gram staining identification showed that the isolates were Gram-positive rods. Of the 120 LAB isolates, five strains displayed moderate to strong antibacterial activity against S. mutans with the inhibition zones ranging from 7- 12 mm. The antibacterial activity demonstrated from LAB isolated from fermented foods suggests that the isolates from fermented foods possess antibacterial properties against a pathogen which responsible for causing dental caries. These strains are currently investigated in depth to assess whether they can be fully characterized as probiotics.

Background Probiotics can be described as live microorganism which when consumed in adequate amounts, it will confer health benefits to the host. The benefits arising from probiotics has been mostly shown on gut health. However, its function to oral health is still poorly investigated. The aim of this study was to isolate lactic acid bacteria (LAB) from local fermented food and to determine its antibacterial activity, in order to select candidate probiotic strains for preventing caries. Methods The probiotic strains were isolated from five local fermented food which are tapai ubi, tapai pulut, rebung, thosai and taucu. Ten-fold serial dilutions of the fermented food samples were made in sterile peptone water before plating on de Man Rogosa and Sharpe (MRS) agar. The pure cultures were then randomly picked and biochemically identified. Then, the antibacterial activity of LAB against Streptococcus mutans were assessed by using disk diffusion method. Results A total of 120 LAB were isolated from five different fermented foods. The morphology of the isolates were circular, convex, dull opaque white or translucent white. Gram-staining identification showed that the isolates were Gram-positive rods. Of the 120 LAB isolates, 6 strains displayed moderate to strong antibacterial activity against S. mutans with the inhibition zones ranging from 7-12 mm. Conclusion The antibacterial activity demonstrated from LAB isolated from local fermented foods suggests that the isolates from local fermented foods possess antibacterial properties against pathogen responsible for causing dental caries. These strains are currently investigated in depth to assess whether they can be fully characterized as probiotics.

Mitogen-activated protein kinases (MAPKs) regulate brain function and their dysfunction is implicated in a number of brain disorders, including Alzheimer’s disease. Thus, there is great interest in understanding the signaling systems that control MAPK function. One family of proteins that contribute to this process, the mitogen-activated protein kinase phosphatases (MKPs), directly inactivate MAPKs through dephosphorylation. Recent studies have identified novel functions of MKPs in development, the immune system, and cancer. However, a significant gap in our knowledge remains in relation to their role in brain functioning. Here, using transgenic mice where the Dusp4 gene encoding MKP-2 has been knocked out (MKP-2 / mice), we show that long-term potentiation is impaired in MKP-2 / mice compared with MKP-2 / controls whereas neuronal excitability, evoked synaptic transmission, and paired-pulse facilitation remain unaltered. Furthermore, spontaneous EPSC (sEPSC) frequency was increased in acute slices and primary hippocampal cultures prepared from MKP-2 / mice with no effect on EPSC amplitude observed. An increase in synapse number was evident in primary hippocampal cultures, which may account for the increase in sEPSC frequency. In addition, no change in ERK activity was detected in both brain tissue and primary hippocampal cultures, suggesting that the effects of MKP-2 deletion were MAPK independent. Consistent with these alterations in hippocampal function, MKP-2 / mice show deficits in spatial reference and working memory when investigated using the Morris water maze. These data show that MKP-2 plays a role in regulating hippocampal function and that this effect may be independent of MAPK signaling.

This study investigated the probiotic characteristics of lactic acid bacteria (LAB) isolated from 14 Malaysian fermented food or milk products. In total, 22.3% (121 of 542) of the LAB isolated from the local fermented products exhibited antibacterial activity against Micrococcus luteus. Twelve LAB that demonstrated better antibacterial activity against M. luteusas compared to a commercial strain Lactobacillus case istrain Shirota(LABPC) were selected for further characterisation. Based on 16S rRNA gene sequence, the LAB were identified as pediococci (seven) and lactobacilli (five). All 12 LAB showed bile tolerance, but only eight were acid tolerant at pH‡3.0. The highest level of adhesion to HT-29 cells was observed among the Lactobacillussp. LAB 1 and 10. The LAB also showed antimicrobial activity against Escherichia coli and Staphylococcusaureus through the production of organic acids. LAB isolated from Malaysian fermented food and milk products, especially fermented tapioca, contains potential probiotic candidates.

The understanding and capability to simulate reproducible in vitro plaque model are important where this artificial plaque can be utilized as a tool in assessing the efficacy of tooth cleaning products. Previous studies were done on synthetic surfaces such as glass beads under a very strict, controlled environment. Thus, the aim of this study was to establish a simplified system to enable the formation of single species biofilm on the extracted natural tooth as plaque model. Healthy extracted natural tooth was incubated in broth mixture of Streptococcus mutans, containing 5% sucrose and stimulated saliva in a simplified system. The incubation was set at room temperature for 24, 48, and 72 hours. After 24 hours, the sticky deposit was formed on the surface of the tooth. The area of biofilm, stained with disclosing agent, expended from 19.05 ± 1.41 mm2 (24 hours) to 23.25 ± 0.35 mm2 (48 hours). However, no significant expansion of the plaque area was observed on 72 hours (23.83 ± 0.52 mm2). The biofilm was then observed under Infinite Focus Microscope (IFM) to measure the biofilm thickness. The preliminary attempt showed that plaque appeared as dark deposit with a certain thickness. Therefore, this simplified system is a reliable method for producing artificial plaque.

Background. Acmella paniculata has been used as a traditional medicine to treat oral health diseases such as dental caries and periodontitis. Streptococcus mutans is a common bacterium that initiates dental caries at an early stage. Aim. The aim of this study was to determine the mode of action of A. paniculata (extracts) against S. mutans growth. Methods. Time-kill assay has been done to investigate the rate of kill and effectiveness of Acmella paniculata (AP) extracts against S. mutans growth. Phytochemical analysis was done to identify major compounds in AP extracts using gas chromatography mass spectrometry (GCMS). Scanning and transmission electron microscopy (SEM and TEM) have been done to observe the morphological changes of treated bacteria. Transcriptomic profile analysis has been done using Next Gene Sequencing. Results. AP flower n-hexane (APFH) and AP flower dichloromethane (APFD) extracts acted as bactericidal agents after killing >3 log10 cfu/mL of S. mutans after 24 hours. Oleic and hexadecenoic acids were found to be the major compounds in APFD and APFH extracts, respectively. Photomicrographs from SEM and TEM of treated S. mutans show that the bacterial cell wall has been lysed and the cytoplasm content was decreased. Pathway analysis revealed that the APFD extract significantly affected biosynthesis peptidoglycan, gene expression, RNA processing, and macromolecule metabolism processes in S. mutans. Conclusion. Data analysis revealed that multiple mechanisms of action were involved in antibacterial activity of A. paniculata extracts toward S. mutans.

We demonstrate fluorescence imaging by two-photon excitation without scanning in biological specimens as previously described by Hwang and co-workers, but with an increased field size and with framing rates of up to 100 Hz. During recordings of synaptically-driven Ca2+ events in primary rat hippocampal neurone cultures loaded with the fluorescent Ca2+ indicator Fluo-4 AM, we have observed greatly reduced photo-bleaching in comparison with single-photon excitation. This method, which requires no costly additions to the microscope, promises to be useful for work where high time-resolution is required.