Listeriosis is a severe foodborne illness characterized by a fatality rate exceeding 30%, attributed to the pathogen Listeria monocytogenes. This study evaluated 160 lactic acid bacteria (LAB) isolated from Thai pickled crabs for their potential as agents against L. monocytogenes and for their probiotic properties and probiogenomic characteristics. Among these strains, strain DRC3-2 exhibited activity through the synthesis of bacteriocin DRC3-2, which significantly inhibited L. monocytogenes ATCC 19115 in spot-on-lawn assays. Phenotypic and whole-genome analyses revealed that strain DRC3-2 thrived in environments with 2-6% NaCl, pH values ranging from 3 to 9, and temperatures between 25 and 45°C. Based on average nucleotide identity (ANI) and digital DNA‒DNA hybridization (dDDH) values, strain DRC3-2 was taxonomically classified as Lactococcus lactis subsp. hordinae. The production of bacteriocin DRC3-2 peaked during the late stationary phase, following its synthesis in the early exponential growth phase. BAGEL4 analysis identified the putative novel bacteriocin DRC3-2 as lactococcin A and B, with respective bit-scores of 40.05 and 36.58. In silico safety assessments confirmed the nonpathogenic nature of strain DRC3-2 in humans, highlighting its absence of antibiotic resistance genes. Finally, this investigation underscores the novel bacteriocin DRC3-2 for application in the prevention and treatment of L. monocytogenes infections.
Listeria monocytogenes เป็นเชื้อก่อโรคที่มักพบในอาหารที่มีการปนเปื้อน สามารถอยู่รอดในสภาวะที่รุนแรง เช่น อุณหภูมิต่ำ ความเป็นกรดสูง ความเข้มข้นของเกลือสูง ซึ่งทำให้มีความเสี่ยงอย่างมากในระบบย่อยอาหารของมนุษย์ ดังนั้นจึงศึกษาแบคทีเรียกรดแลคติกที่มีความสำคัญในอุตสาหกรรมอาหารและยาเนื่องจากมีคุณสมบัติเป็นโพรไบโอติก และแบคทีเรียกรดแลคติกบางชนิดที่สามารถผลิตแบคเทอริโอซินหรือเปปไทด์ต้านจุลชีพที่มีฤทธิ์ทางชีวภาพ และแบคเทอริโอซินที่มีประสิทธิภาพในการยับยั้งแบคทีเรียก่อโรค ซึ่งถือว่าเป็นทางเลือกที่น่าสนใจแทนการใช้ยาปฎิชีวนะแบบดั้งเดิม เนื่องจากช่วยลดการพัฒนาการดื้อยาของแบคทีเรีย นอกจากนี้แบคเทอริโอซินยังมีความเสถียรสูง สามารถทนต่ออุณหภูมิที่รุนแรงและสภาวะเป็นกรดได้ อีกทั้งยังไม่เป็นพิษต่อเซลล์มนุษย์ การศึกษานี้จึงมุ่งหมายเพื่อศึกษาแบคเทอริโอซินชนิดใหม่จาก Lactococcus lactis subsp. hordinae DCR3-2 ซึ่งแยกได้จากปูดอง เพื่อประเมินฤทธิ์การต้านจุลชีพของแบคทีเรียชนิดนี้ และการวิเคราะห์ทางbioinformatics เพื่อยืนยันว่าสายพันธุ์ DCR3-2 มีความปลอดภัยสำหรับมนุษย์และมีคุณสมบัติโพรไบโอติก
คณะวิศวกรรมศาสตร์
This study was conducted to develop a prototype cooling cover for transporting raw milk, aiming to provide a solution for maintaining the quality of raw milk during transportation to milk collection centers. The cooling cover is made using Phase Change Material (PCM), produced from water mixed with a gelling agent, in an amount of 5.6 kg, attached around an aluminum milk tank (with a capacity of 25 L). The cover is then covered with a UV-reflective fabric in two types: polyvinyl chloride (PVC) and high-density polyethylene (HDPE). The temperature reduction performance of both types of covers was evaluated by measuring water temperatures at various points along the radial and vertical directions of the milk tank at six points, using type-T thermocouples, under three environmental conditions: a constant temperature of 25 °C, 35 °C, and outdoor ambient temperature (average temperature 35.5 °C) for a minimum duration of 180 min. The experimental results revealed that at 120 min., the water in the tank covered with PCM-PVC and PCM-HDPE covers had temperatures lower than the ambient temperature by 12.6 °C and 12.9 °C, respectively, under a constant ambient temperature of 25 °C, and under a constant ambient temperature of 35 °C lower by 16.7 °C and 16.4 °C, respectively, and outdoor conditions. Since the temperature reduction performance of PCM-PVC and PCM-HDPE covers showed no significant difference, the performance of microbial quality preservation of raw milk was assessed only with PCM-PVC cover in comparison to a non-covered case (control), by measuring coliform and Escherichia coli counts using compact dry plates. Results indicated that after 120 min., milk in the tank covered with PCM-PVC had an average coliform count of 1.6 × 10^4 CFU/ml and E. coli count of 2 × 10^3 CFU/ml, which was lower than the non-covered control with an average coliform count of 1.5 × 10^4 CFU/ml and E. coli count of 1.1 × 10^4 CFU/ml. This study concludes that the temperature reduction achieved by the cooling cover can help inhibit coliform growth to levels below raw milk quality standards, demonstrating the potential of the cooling cover in maintaining the quality and safety of raw milk during transport, ultimately contributing to an improved quality of life for Thai dairy farmers.
วิทยาลัยวิศวกรรมสังคีต
Some musicians are hearing impaired, some have finished their careers, but some continue to work, and it is much harder for them to be deaf than for musicians who are not. Some use hearing aids in their daily lives and use in-ear monitors in their live performances, which seem normal, but in their in-ears they only hear the metronome and drums. How can we improve the performance of in-ear monitors to near normal?
คณะวิทยาศาสตร์
Currently, climate change and human activities are causing rapid deterioration of coral reefs worldwide. Monitoring coral health is essential for marine ecosystem conservation. This project focuses on developing an Artificial Intelligence (AI) model to classify coral health into four categories: Healthy, Bleached, Pale, and Dead using Deep Learning techniques. With pre-trained convolutional neural network (CNN) for image classification. To improve accuracy and mitigate overfitting, 5-fold Cross-Validation is employed during training, and the best-performing model is saved. The results of this project can be applied to monitor coral reef conditions and assist marine scientists in analyzing coral health more efficiently and accurately. This contributes to better conservation planning for marine ecosystems in the future.