Name of Supervisor: Yoshitsugu Ochiai, D.V.M., Ph.D. (Veterinary Science)
Position: Professor
Researchmap
KAKEN researcher number: 40350178
Main research theme: Control of foodborne diseases caused by pathogenic bacteria
Research keywords: Listeria monocytogenes, stress tolerance, isolation of bacteria, Quiescence（Dormancy, Persistence）
Lab. Location: Veterinary Public Health, 4th floor, Building D
E-mail: yochiai(@mark)nvlu.ac.jp
Research
I am conducting research that aims to eliminate pathogenic bacteria caused by foodborne infections from food contamination sources by elucidating their ecology. I currently focus on Listeria monocytogenes, which causes lethal infections in immunocompromised persons. Many pathogenic bacteria of foodborne infections, including Salmonella, Campylobacter, and enterohemorrhagic Escherichia coli, inhabit the gastrointestinal tracts of humans and animals, whereas L. monocytogenes is established in food processing environments. Bacterial species that inhabit the internal environments of humans and animals are almost completely different from those in food processing environments because of dissimilarities in abiotic factors, including temperature, nutrient levels, pH, salt concentration, and other conditions. However, it is known that a small number of pathogenic bacteria, including L. monocytogenes, have the ability to adapt and grow in diverse environments. I am focusing on the adaptability of L. monocytogenes to a wide range of environments and am attempting to elucidate which properties of this bacterium are involved in this adaptability. Currently, we are conducting analyses focusing on how L. monocytogenes responds to unfavorable environmental conditions for its growth and survival.
Guidance policy for graduate students
I think it is important for researchers to always address their research with the mindset of “carrying out experiments strictly and examining closely and objectively the results obtained.”
As researchers, we are responsible for the content of academic papers as soon as they have been published. After publication, other research groups should be able to obtain the same results when conducting supplementary tests. In this way, I believe that, by comparing each other’s research results, researchers will be able to accumulate findings, which makes it possible for science to be close to the truth of natural phenomena. However, if reproducibility is not achieved in subsequent examinations, confusion will arise in the scientific field in the future. During the research process, I would like to guide graduate students with an emphasis on ensuring the reproducibility of experimental results and moving forward step by step.
In my research, I focus on the phenomena that occur during biological experiments. As we continue to conduct experiments with bacteria every day, we may witness unexpected phenomena. Some of these phenomena have already been reported, but there are also others that may be new discoveries. I would like to teach graduate students in a way that allows them to experience the joy of gaining knowledge through careful observation.
Publications
1. Ochiai Y, Yoshikawa Y, Mochizuki M, Takano T, Ueda F.
Unique response characteristics in persistent strains of Listeria monocytogenes exposed to low pH.
Food Microbiol, 86, 103312, 2020.
doi: 10.1016/j.fm.2019.103312
2. Ochiai Y, Yamada F, Yoshikawa Y, Mochizuki M, Takano T, Hondo R, Ueda F.
Sequential transition of the injury phenotype, temperature-dependent survival and transcriptional response in Listeria monocytogenes following lethal H2O2 exposure.
Int J Food Microbiol, 259, 52-58, 2017.
doi: 10.1016/j.ijfoodmicro.2017.08.001
3. Ochiai Y, Mochizuki M, Yamada F, Takano T, Hondo R, Ueda F.
Genetic classification of Listeria monocytogenes serotype 4b strains, including epidemic clones, isolated from retail meat in the Tokyo metropolitan.
Jpn J Infect Dis, 67, 258-263, 2014.
doi: 10.7883/yoken.67.258
4. Ochiai Y, Yamada F, Mochizuki M, Takano T, Hondo R, Ueda F.
Biofilm formation under different temperature conditions by a single genotype of persistent Listeria monocytogenes strains.
J Food Prot, 77, 133-140, 2014.
doi; 10.4315/0362-028X.JFP-13-074
5. Ochiai Y, Yamada F, Otgomchimeg B, Ogasawara K, Mochizuki M, Hondo R, Ueda F.
Prevalence of Listeria monocytogenes in retailed meat in the Tokyo metropolitan area.
J Food Prot, 73, 1688-1693, 2010.
doi: 10.4315/0362-028X-73.9.1688
