This research aimed to isolate and culture four strains of lactic acid bacteria (LAB) isolated from fermented foods. The antimicrobial activity of the lactic acid bacteria was studied using the agar spot method and the antibiotic resistance properties of the lactic acid bacteria were studied using the agar overlay diffusion method. The results showed that each strain of lactic acid bacteria had different levels of antimicrobial activity and antibiotic resistance, which are safety properties of probiotic microorganisms.
จุลินทรีย์โพรไบโอติก (Probiotic) หมายความว่า จุลินทรีย์ที่มีชีวิต ซึ่งเมื่อร่างกายได้รับในปริมาณที่เพียงพอจะทำให้เกิดผลที่เป็นประโยชน์ต่อสุขภาพ อาหารที่มีการใช้จุลินทรีย์โพรไบโอติกต้องได้รับอนุญาตจากสำนักงานคณะกรรมการ อาหารและยา และ ต้องใช้จุลินทรีย์ตามที่กำหนดไว้ ดังนั้นการวิจัยนี้จึงนำเชื้อแบคทีเรียแลคติกที่แยกได้จากอาหารหมัก 4 สายพันธุ์ มาศึกษาฤทธิ์การต้านเชื้อแบคทีเรียก่อโรคในอาหาร และ ศึกษาสมบัติการดื้อยาของเชื้อแบคทีเรียแลคติก
คณะวิทยาศาสตร์
This research aims to select the location of the beverage distribution center of Thai Spirit Industry Co., Ltd. with the lowest total cost of transportation. using a mathematical model by considering the Muang districts of all 76 provinces, excluding Chachoengsao Province, where the factory is located. In the present study, four scenarios were divided: 1) when only one distribution center was required; 2) when more than one distribution center was established; 3) when it was divided into 4 regions. There can only be one distribution center in one region, and 4) when it is divided into four regions, where more than one distribution center can be established in one region. When processed with the program IBM ILOG CPLEX Optimization Studio, the results are summarized as follows: Scenario 1, when only one distribution center is assigned. The total transportation cost is 786,107.75 baht/month. Scenario 2, when more than one distribution center can be established. The total transportation cost is 252,338.98 baht/month. Scenario 3, when divided into 4 regions by requiring only one distribution center in one region. The total transportation cost is 401,499.61 baht/month. Scenario 4, when divided into 4 regions by requiring that there is more than one distribution center in each region. The total transportation cost is 258,666.22 baht/month.
วิทยาเขตชุมพรเขตรอุดมศักดิ์
This project aims to design and develop a propulsion system for agricultural equipment using RFID technology and evaluate its movement performance on different surfaces, including concrete and grass. The experiment focuses on examining the tag detection range under transmission power levels of 20 dBm, 23 dBm, and 26 dBm, as well as the impact of antenna angles on detection efficiency. Additionally, the system was tested in three movement scenarios: straight path, left turn, and right turn, at distances of 2 meters, 4 meters, and 6 meters. The results indicate that the system achieved the highest average speed of 0.4736 m/s and an average turning angle of 91.6° when moving in a straight path on a concrete surface at a distance of 4 meters. On a grass surface at the same distance, the average speed was 0.4483 m/s, with an average turning angle of 91.1°. For left and right turns, the movement on the concrete surface generally exhibited a higher average speed than on grass, particularly at a distance of 4 meters, where differences in turning angles were observed. This study provides insights into the factors affecting the movement of agricultural mowing equipment and serves as a foundation for enhancing the efficiency of propulsion systems in future developments.
คณะทันตแพทยศาสตร์
Objective or Background: Dental caries is still one of the most significant dental problems worldwide, with prevalence rates up to 90% among children and adults. Cariogenic bacteria, especially Streptococcus mutans, is the primary microorganism involved in the pathogenesis through carbohydrate metabolism and biofilm formation, which are challenging to eradicate. Histatin-5 (HST-5), a human salivary antimicrobial peptide, has demonstrated antimicrobial activity against various fungal and bacterial pathogens. Phytosphingosine (PHS), an endogenous bioactive sphingolipid found in fungi, plants, and humans, also shows antimicrobial properties. This study aimed to evaluate the killing activity of HST-5 alone and in combination with PHS against S. mutans under biofilm-stimulating conditions. Materials and Methods: Antimicrobial activity against a planktonic culture of S. mutans was evaluated using a time-kill assay, and biofilm-forming capacity was confirmed by crystal violet staining assay. The killing ability against 24h pre-formed biofilm was determined using Transferable Solid Phase (TSP) pin lid model. Synergistic activity between HST-5 and PHS was evaluated using the checkerboard technique. Additionally, the cytotoxicity of the tested agent on human gingival fibroblast cells (hGFs) was assessed after 1 h of incubation using an MTT assay. Results: A time-kill assay revealed that both HST-5 and PHS exhibit time- and concentration-dependent activity against the planktonic form of S. mutans. PHS achieved over 90% killing activity within 15 min at 5 μg/ml, whereas HST-5 required 30 min to reach 90% killing at 20 μM. The biofilm formation capacity of S. mutans was confirmed. The inhibitory concentrations (IC50) of HST-5 and PHS against S. mutans biofilm were 25 μM and 13.5 μg/ml, respectively. A synergistic interaction between HST-5 and PHS, with IC50 values reduced by 8-fold and 16-fold, respectively. No cytotoxic effects were observed in hGFs cells at the concentration of the synergistic interaction. Conclusions: Therefore, the combination of HST-5 and PHS may enhance the effectiveness of anti-infective agents against S. mutans biofilm, potentially preventing the development of dental caries.