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
คณะสถาปัตยกรรม ศิลปะและการออกแบบ
A Photographic series that expresses the abstract states of myself, towards the question of existence that results from being surrounded by expectations of both surrender and freedom of expression, this series focuses on my own subjectivities in order to bring back memories of almost forgotten feelings and make them clear once more.
คณะครุศาสตร์อุตสาหกรรมและเทคโนโลยี
This aimed to 1) develop an effective augmented reality (AR) media integrated with the metaverse to enhance English phonics and communication skills. 2) To evaluate English pronunciation skills using augmented reality media integrated with the metaverse, and 3) To assess English communication skills through interactions within the metaverse. The sample group comprised 120 Grade 4 students from two classrooms in the first semester of the 2024 academic year, selected through cluster random sampling and divided into experimental and control groups. The research instruments included AR media sets, media quality assessment forms, phonics tests, and English communication skills assessment forms, administered before and after the learning intervention. Data analysis employed mean (x ̅), standard deviation (S), t-tests for independent samples, and one-way analysis of variance (Multivariate Analysis of Variance: One-Way MANOVA) to compare mean score differences between the experimental and control groups. Results indicated that the overall quality of the AR media kit with the metaverse was rated at a very high level (x ̅= 4.80, S.D. = 0.12). Evaluating specific aspects showed that the content quality was at the highest level (x ̅= 4.92, S.D. = 0.07), while the media production technique also rated highly (x ̅ = 4.70, S.D. = 0.17). Furthermore, the English pronunciation and communication skills of the Grade 4 students using the AR media with the metaverse were significantly higher after the intervention compared to before, the overall quality of the AR media integrated with the metaverse was rated at the highest level (x ̅= 4.80, S.D. = 0.12). For individual aspects, content quality was rated at the highest level (x ̅= 4.92, S.D. = 0.07), and media production techniques were also rated at the highest level (x ̅ = 4.70, S.D. = 0.17). Comparing the mean scores of English pronunciation and communication skills between the two groups, it was found that the experimental group using AR media integrated with the metaverse demonstrated significantly higher English pronunciation skills than the control group (F(1, 89) = 3261.422, p = 0.001, Partial η² = 0.98). Additionally, the experimental group exhibited significantly higher English communication skills than the control group (F(1, 89) = 4239.365, p = 0.001, Partial η² = 0.98). These results aligned with the research hypothesis that "Grade 4 students’ English pronunciation and communication skills post-learning with AR media integrated with the metaverse would significantly improve compared to their pre-learning levels at the .05 level of significance.
คณะเทคโนโลยีการเกษตร
Threadfin breams is an economically important fish that can be found in fisheries in both the Gulf of Thailand and Andaman Sea and is cheap. In addition, the consumption of raw fish as sashimi is increasingly popular in Thailand. Therefore, it is necessary to promote its consumption to increase its value. This study investigated the preservation of threadfin breams (N. furcosus) for raw or sashimi consumption. The preservation of threadfin breams consisted of Ikejime (K) and cold seawater (S) methods, and the preservation of the fish by Gutting (G) and whole (W) and storing for 3 days on ice (I) or in a refrigerator (F). The freshness quality of threadfin breams was evaluated by sensory, physicochemical (TVB-N, TMA-N and pH), freshness index (Ki-value) and microbiological methods. It was found that after being stored for 3 days, the KGF group of threadfin breams had the highest overall sensory score, which was 8.36±0.80 points, and the KWI, SWI and SWF groups of threadfin breams had the lowest overall sensory scores, which were 8.13±0.77, 8.13±0.77 and 8.13±0.81 points, respectively. And the overall sensory scores of all experimental groups of fish increased significantly (p<0.05). The TVB-N value of threadfin breams in KGF group had the lowest TVB-N value, which was 1.37±0.93 mg nitrogen/100 g sample. The threadfin breams in SGI group had the highest TVB-N value, which was 2.36±1.15 mg nitrogen/100 g sample. The TVB-N of fish in all experimental groups increased significantly (p<0.05). The TMA-N value of threadfin breams in KGF group had the lowest TMA-N value, which was 1.56±0.88 mg nitrogen/100 g sample. The threadfin breams in SWF group had the highest TMA-N value, which was 2.17±1.22 mg nitrogen/100 g sample. The TMA-N of fish in all experimental groups increased significantly (p<0.05). The pH value of threadfin breams in KGF group had the lowest pH value, which was 6.40±0.12. The threadfin breams in SWF group had the highest pH value, which was 6.78±0.25. The pH of fish in all experimental groups increased significantly (p<0.05). Ki value The threadfin breams in KGF group had the lowest Ki value, which was 9.05±0.73%. The threadfin breams in KWI group had the highest Ki value, which was 12.88±4.19%. The Ki value of all experimental groups of fish increased without statistical significance (p>0.05). In terms of freshness quality in microbiology, it was found that in all experimental groups, Salmonella spp., S. aureus, B. cereus, C. perfringens and E. coli were found in all experimental groups of threadfin breams. All types of microorganisms in all groups of threadfin breams increased with statistical significance (p<0.05). When compared with the freshness quality criteria in terms of sensory, chemical, physical, freshness index and microbiology, it was found that all groups of threadfin breams were very fresh and suitable for raw consumption during the preservation and storage for 3 days. After 3 days of storage, the threadfin breams should be consumed cooked because the freshness quality of the fish is not suitable for raw consumption due to the increase in various parameters. The increase in various parameters is due to the deterioration of the fish and the activities of microorganisms. Therefore, threadfin breams is suitable to promote raw consumption within 3 days of storage. In addition, fish preservation, especially by Ikejime method, then cutting open the belly and storing in the refrigerator, can help improve the freshness of the fish. The results of this study can be used to develop techniques for preserving fish after capture for fishermen and can promote the increase in the value of threadfin breams in the future.