著者
SHUKUO KINOSHITA SHIGEZO UDAKA MASAKAZU SHIMONO
出版者
公益財団法人 応用微生物学・分子細胞生物学研究奨励会
雑誌
The Journal of General and Applied Microbiology (ISSN:00221260)
巻号頁・発行日
vol.3, no.3, pp.193-205, 1957 (Released:2006-08-11)
参考文献数
11
被引用文献数
78 408

1. Screening tests for glutamate producing strains were carried out, with the media containing carbohydrate and ammonia source as chief ingredients. Glutamate as well as certain other amino acids was detected by paper chromatography in culture broth of many microorganisms tested.2. Accumulation of L-glutamate in a significant amount (at least a few mg of glutamate per ml of broth) has been demonstrated by various strains of bacteria, streptomycetes, yeasts, and fungi. The highest level of glutamate production has been obtained by a new species of Micrococcus, yielding as much as 0.25 mole of it from one mole of glucose.3. The courses of fermentations mainly by known strains of microorganisms are shown. The importances of the cultural condition and strain specificity for the production of amino acids are briefly described.
著者
Gen Enomoto Ayako Kamiya Yukiko Okuda Rei Narikawa Masahiko Ikeuchi
出版者
Applied Microbiology, Molecular and Cellular Biosciences Research Foundation
雑誌
The Journal of General and Applied Microbiology (ISSN:00221260)
巻号頁・発行日
pp.2020.01.007, (Released:2020-03-30)
参考文献数
43
被引用文献数
6

Second messenger molecules are crucial components of environmental signaling systems to integrate multiple inputs and elicit physiological responses. Among various kinds of second messengers, cyclic nucleotides cAMP and cyclic di-GMP (c-di-GMP) play pivotal roles in bacterial environmental responses. However, how these signaling systems are interconnected for a concerted regulation of cellular physiology remains elusive. In a thermophilic cyanobacterium Thermosynechococcus vulcanus strain RKN, incident light color is sensed by cyanobacteriochrome photoreceptors to transduce the light information to the levels of c-di-GMP, which induces cellular aggregation probably via cellulose synthase activation. Herein, we identified that Tlr0485, which is composed of a cGMP-specific phosphodiesterases, adenylate cyclases, and FhlA (GAF) domain and an HD-GYP domain, is a cAMP-activated c-di-GMP phosphodiesterase. We also show biochemical evidence that the two class-III nucleotide cyclases, Cya1 and Cya2, are both adenylate cyclases to produce cAMP in T. vulcanus. The prevalence of cAMP-activated c-di-GMP phosphodiesterase genes in cyanobacterial genomes suggests that the direct crosstalk between cAMP and c-di-GMP signaling systems may be crucial for cyanobacterial environmental responses.
著者
Michio Matsuhashi Alla N. Pankrushina Satoshi Takeuchi Hideyuki Ohshima Housaku Miyoi Katsura Endoh Ken Murayama Hiroshi Watanabe Shigeo Endo Mikio Tobi Yoshihiro Mano Masao Hyodo Torakichi Kobayashi Tomohiko Kaneko Sugio Otani Susumu Yoshimura Akira Harata Tsuguo Sawada
出版者
公益財団法人 応用微生物学・分子細胞生物学研究奨励会
雑誌
The Journal of General and Applied Microbiology (ISSN:00221260)
巻号頁・発行日
vol.44, no.1, pp.49-55, 1998 (Released:2005-08-24)
参考文献数
19
被引用文献数
9 55

Bacterial cells enhance the proliferation of neighboring cells under stress conditions by emitting a physical signal. Continuous single sine sound waves produced by a speaker at frequencies of 6–10, 18–22, and 28–38 kHz promoted colony formation by Bacillus carboniphilus under non-permissive stress conditions of high KCl concentration and high temperature. Furthermore, sound waves emitted from cells of Bacillus subtilis at frequencies between 8 and 43 kHz with broad peaks at approximately 8.5, 19, 29, and 37 kHz were detected using a sensitive microphone system. The similarity between the frequency of the sound produced by B. subtilis and the frequencies that induced a response in B. carboniphilus and the previously observed growth-promoting effect of B. subtilis cells upon B. carboniphilus through iron barriers, suggest that the detected sound waves function as a growth-regulatory signal between cells.
著者
Tomonori Kashimoto Keita Miyake Mayuko Sato Kaisei Maeda Chikahiro Matsumoto Masahiko Ikeuchi Kiminori Toyooka Satoru Watanabe Yu Kanesaki Rei Narikawa
出版者
Applied Microbiology, Molecular and Cellular Biosciences Research Foundation
雑誌
The Journal of General and Applied Microbiology (ISSN:00221260)
巻号頁・発行日
pp.2019.11.008, (Released:2020-03-07)
参考文献数
43
被引用文献数
5

The cyanobacterium Acaryochloris marina MBIC 11017 (A. marina 11017) possesses chlorophyll d (Chl. d) peaking at 698 nm as photosystem reaction center pigments, instead of chlorophyll a (Chl. a) peaking at 665 nm. About 95% of the total chlorophylls is Chl. d in A. marina 11017. In addition, A. marina 11017 possesses phycobilisome (PBS) supercomplex to harvest orange light and to transfer the absorbing energy to the photosystems. In this context, A. marina 11017 utilizes both far-red and orange light as the photosynthetic energy source. In the present study, we incubated A. marina 11017 cells under monochromatic orange and far-red light conditions and performed transcriptional and morphological studies by RNA-seq analysis and electron microscopy. Cellular absorption spectra, transcriptomic profiles, and microscopic observations demonstrated that PBS was highly accumulated under an orange light condition relative to a far-red light condition. Notably, transcription of one cpcBA operon encoding the phycobiliprotein of the phycocyanin was up-regulated under the orange light condition, but another operon was constitutively expressed under both conditions, indicating functional diversification of these two operons for light harvesting. Taking the other observations into consideration, we could illustrate the photoacclimation processes of A. marina 11017 in response to orange and far-red light conditions in detail.
著者
Yuko Goto Naoko Yoshida
出版者
公益財団法人 応用微生物学・分子細胞生物学研究奨励会
雑誌
The Journal of General and Applied Microbiology (ISSN:00221260)
巻号頁・発行日
pp.2016.10.001, (Released:2017-05-02)
参考文献数
31
被引用文献数
15

Anodes are crucial in determining the electricity recovery of microbial fuel cells (MFCs). In this study, graphene oxide (GO) was used as an anodic material for electricity recovery from artificial dialysis wastewater (ADWW). Anaerobic incubation of ADWW with GO for 21 days produced a hydrogel complex containing embedded microbial cells and microbially reduced GO (rGO). The rGO complex recovered 540 to 810 μA/cm3 of catalytic current from ADWW after 10 days of electrochemical cultivation at 200 mV (vs. Ag/AgCl), which was approximately thirty times higher than that recovered from graphite felt (GF), a representative anode in MFCs. High-throughput sequencing analysis of prokaryotic 16S rRNA genes revealed a predominance of the Geobacter genus (35% of all prokaryotic sequences identified), particularly in the rGO complex after 20 days of polarization. The superior electricity recovery of the rGO complex was attributable to enhanced direct electron transfer via a well-developed biofilm, while indirect electron transfer via an electron mediator occurred in culture using GF.
著者
Kazuki Ohta Tenma Shimizu Taku Oshima Norikazu Ichihashi
出版者
Applied Microbiology, Molecular and Cellular Biosciences Research Foundation
雑誌
The Journal of General and Applied Microbiology (ISSN:00221260)
巻号頁・発行日
pp.2022.10.003, (Released:2022-11-15)
参考文献数
29

Various bacteria can change to a spherical cell-wall-deficient state, called L-from, in the presence of antibiotics that inhibit cell wall synthesis. L-forms are classified into two types: unstable and stable L-forms. Unstable L-forms revert to a normal walled state in the absence of antibiotics, while stable L-forms remain in their wall-deficient state. The conversion from unstable to stable L-forms has been often observed during long-term cultivation. However, the genetic cause for this conversion is not yet fully understood. Here, we obtained stable Bacillus subtilis L-form strains from unstable L-form strains via three independent long-term culturing experiments. The whole genome sequencing of the long-cultured strains identified many mutations, and some mutations were commonly found in all three long-cultured strains. The knockout strain of one of the commonly mutated genes, tagF, in the ancestral strain lost the ability to revert to walled state (rod shape), supporting that eliminating the function of tagF gene is one of the possible methods to convert unstable L forms to a stable state.
著者
Naoya Shimada Yukiko Okuda Kaisei Maeda Daisuke Umeno Shinichi Takaichi Masahiko Ikeuchi
出版者
Applied Microbiology, Molecular and Cellular Biosciences Research Foundation
雑誌
The Journal of General and Applied Microbiology (ISSN:00221260)
巻号頁・発行日
pp.2020.01.003, (Released:2020-03-25)
参考文献数
24
被引用文献数
9

Heterologous production of a useful carotenoid astaxanthin was achieved in a cyanobacterium Synechocystis sp. PCC 6803 with the aid of marine bacterial genes. Astaxanthin and its intermediates emerged at high levels, whereas β-carotene and zeaxanthin disappeared in the strain. Total carotenoid accumulation was nearly two fold compared with wild type. The astaxanthin-producing strain was capable of only growing heterotrophically, which was likely due to the absence of β-carotene. Further enhanced accumulation was pursued by gene overexpression for possible rate-limiting steps in the biosynthesis pathway.
著者
Thi Huyen Do Ngoc Giang Le Trong Khoa Dao Thi Mai Phuong Nguyen Tung Lam Le Han Ly Luu Khanh Hoang Viet Nguyen Van Lam Nguyen Lan Anh Le Thu Nguyet Phung Nico M. van Straalen Dick Roelofs Nam Hai Truong
出版者
Applied Microbiology, Molecular and Cellular Biosciences Research Foundation
雑誌
The Journal of General and Applied Microbiology (ISSN:00221260)
巻号頁・発行日
pp.2017.08.004, (Released:2018-03-12)
参考文献数
55
被引用文献数
11

The scarcity of enzymes having an optimal activity in lignocellulose deconstruction is an obstacle for industrial-scale conversion of cellulosic biomass into biofuels. With the aim of mining novel lignocellulolytic enzymes, a ~9 Gb metagenome of bacteria in Vietnamese native goats’ rumen was sequenced by Illumina platform. From the data, 821 ORFs encoding carbohydrate esterases (CEs) and polysaccharide lyases (PLs) serving for lignocellulose pre-treatment, 816 ORFs encoding 11 glycoside hydrolase families (GHs) of cellulases, and 2252 ORFs encoding 22 GHs of hemicellulases, were mined. The carbohydrate binding module (CBM) was also abundant with 763 ORFs, of which 480 ORFs are located with lignocellulolytic enzymes. The enzyme modularity analysis showed that CBMs are usually present in endoglucanase, endo 1,3-beta-D-glucosidase, and endoxylanase, whereas fibronectin 3-like module (FN3) mainly represents in GH3 and immunoglobulin-like domain (Ig) was located in GH9 only. Every domain located in each ORF was analyzed in detail to contribute enzymes’ modularity which is valuable for modelling, to study the structure, and for recombinant production. With the aim of confirming the annotated results, a mined ORF encoding CBM63 was highly expressed in E. coli in soluble form. The purified recombinant CBM63 exhibited no cellulase activity, but enhanced a commercial cellulase activity in the destruction of a paper filter.
著者
Naoya Shimada Yukiko Okuda Kaisei Maeda Daisuke Umeno Shinichi Takaichi Masahiko Ikeuchi
出版者
Applied Microbiology, Molecular and Cellular Biosciences Research Foundation
雑誌
The Journal of General and Applied Microbiology (ISSN:00221260)
巻号頁・発行日
vol.66, no.2, pp.116-120, 2020 (Released:2020-06-17)
参考文献数
24
被引用文献数
2 9

Heterologous production of a useful carotenoid astaxanthin was achieved in a cyanobacterium Synechocystis sp. PCC 6803 with the aid of marine bacterial genes. Astaxanthin and its intermediates emerged at high levels, whereas β-carotene and zeaxanthin disappeared in the strain. Total carotenoid accumulation was nearly two fold compared with wild type. The astaxanthin-producing strain was capable of only growing heterotrophically, which was likely due to the absence of β-carotene. Further enhanced accumulation was pursued by gene overexpression for possible rate-limiting steps in the biosynthesis pathway.
著者
Courtney Cochran Hisako Masuda
出版者
公益財団法人 応用微生物学・分子細胞生物学研究奨励会
雑誌
The Journal of General and Applied Microbiology (ISSN:00221260)
巻号頁・発行日
vol.62, no.2, pp.47-51, 2016-04-28 (Released:2016-04-27)
参考文献数
14
被引用文献数
1

Bacillus mycoides are known to form rhizoidal colonies on solid medium. In this study, a new strain of B. mycoides, strain Ko01, was isolated from soil. Genetic and growth patterns indicated that this strain belongs to subgroup II of the B. cereus group. Strain Ko01 forms extensive rhizoidal colonies with predictable directions of rotation. The concentration of the agar, and not the chemical composition, altered the direction of the colony rotation, switching from counterclockwise to clockwise. Agar concentration-dependent switching of rotation direction was unique to strain Ko01 and was not seen in colonies of other B. mycoides strains that were tested. Factors affecting colony chirality patterns appeared to be variable among B. mycoides strains. This feature can be used for the classification of B. mycoides strains.
著者
Yu Shinjyo Naoya Midorikawa Takashi Matsumoto Yuki Sugaya Yoshiki Ozawa Ayumi Oana Chiaki Horie Hirofumi Yoshikawa Yasuhiro Takahashi Toshio Hasegawa Kei Asai
出版者
Applied Microbiology, Molecular and Cellular Biosciences Research Foundation
雑誌
The Journal of General and Applied Microbiology (ISSN:00221260)
巻号頁・発行日
vol.68, no.2, pp.62-70, 2022 (Released:2022-09-15)
参考文献数
62
被引用文献数
1

Recently, the antibacterial effects of essential oils have been investigated in addition to their therapeutic purposes. Owing to their hydrophobic nature, they are thought to perturb the integrity of the bacterial cell membrane, leading to cell death. Against such antibiotic challenges, bacteria develop mechanisms for cell envelope stress responses (CESR). In Bacillus subtilis, a gram-positive sporulating soil bacterium, the extracytoplasmic function (ECF) sigma factor-mediated response system plays a pivotal role in CESR. Among them, σM is strongly involved in response to cell envelope stress, including a shortage of available bactoprenol. Vetiver essential oil, a product of Chrysopogon zizanioides (L.) Roberty root, is also known to possess bactericidal activity. σM was exclusively and strongly induced when the cells were exposed to Vetiver extract, and depletion of multi-ECF sigma factors (ΔsigM, ΔsigW, ΔsigX, and ΔsigV) enhanced sensitivity to it. From this quadruple mutant strain, the suppressor strains, which restored resistance to the bactericidal activity of Vetiver extract, emerged, although attempts to obtain resistant strains from the wild type did not succeed. Whole-genome resequencing of the suppressor strains and genetic analysis revealed inactivation of xseB or pnpA, which code for exodeoxyribonuclease or polynucleotide phosphorylase, respectively. This allowed the quadruple mutant strain to escape from cell death caused by Vetiver extract. Composition analysis suggested that the sesquiterpene, khusimol, might contribute to the bactericidal activity of the Vetiver extract.
著者
Toshio Sakamoto Yang Wei Koki Yuasa Yoshitaka Nishiyama
出版者
Applied Microbiology, Molecular and Cellular Biosciences Research Foundation
雑誌
The Journal of General and Applied Microbiology (ISSN:00221260)
巻号頁・発行日
pp.2022.01.003, (Released:2022-05-20)
参考文献数
31
被引用文献数
1

The terrestrial cyanobacterium Nostoc commune is an anhydrobiotic organism with extreme longevity. Recovery of photosynthesis by rehydration was examined using our laboratory stocks of dry N. commune thalli after long-term storage in a desiccated state. In the samples stored at room temperature for over 8 years, photosynthetic oxygen evolution was barely detectable, whereas oxygen consumption was recovered. There was an exceptional case in which photosynthetic oxygen evolution recovered after 8 years of storage at room temperature. Both photosynthetic oxygen evolution and respiratory oxygen consumption were recovered in dry thalli stored at -20°C for over 15 years. Consistent with the recovery of photosynthetic oxygen evolution, Fv/Fm was detected in the samples stored at -20°C at levels similar to those of freshly collected N. commune colonies. Carotenoids, scytonemin and chlorophyll a appeared to be intact in the dry thalli stored at -20°C, but β-carotene was not detected in the samples stored at room temperature. α-Tocopherol was intact in the samples stored at -20°C but was degraded in the samples stored at room temperature. These results suggest that dry thalli of N. commune are capable of sustaining biological activities for a long time, although they are gradually damaged when stored at room temperature.
著者
Yuki Sugimoto Shinji Masuda
出版者
Applied Microbiology, Molecular and Cellular Biosciences Research Foundation
雑誌
The Journal of General and Applied Microbiology (ISSN:00221260)
巻号頁・発行日
pp.2020.06.001, (Released:2020-12-21)
参考文献数
29
被引用文献数
3

Phototaxis is a phenomenon where cyanobacteria move toward a light source. Previous studies have shown that the blue-light-using-flavin (BLUF)-type photoreceptor PixD and the response regulator-like protein PixE control the phototaxis in the cyanobacterium Synechocystis sp. PCC6803. The pixD-null mutant moves away from light, whereas WT, pixE mutant, and pixD-pixE double mutant move toward the light. This indicates that PixE functions downstream of PixD and influences the direction of movement. However, it is still unclear how the light signal received by PixD is transmitted to PixE, and then subsequently transmitted to the type IV pili motor mechanism. Here, we investigated intracellular localization and oligomerization of PixD and PixE to elucidate mechanisms of phototaxis regulation. Blue-native PAGE analysis, coupled with western blotting, indicated that most PixD exist as a dimer in soluble fractions, whereas PixE localized in ~250 kDa and ~450 kDa protein complexes in membrane fractions. When blue-native PAGE was performed after illuminating the membrane fractions with blue light, PixE levels in the ~250 kDa and ~450 kDa complexes were reduced and increased, respectively. These results suggest that PixE, localized in the ~450 kDa complex, controls activity of the motor ATPase PilB1 to regulate pilus motility.
著者
Katsuhiko Okada Shoko Fujiwara Mikio Tsuzuki
出版者
Applied Microbiology, Molecular and Cellular Biosciences Research Foundation
雑誌
The Journal of General and Applied Microbiology (ISSN:00221260)
巻号頁・発行日
pp.2020.02.002, (Released:2020-04-24)
参考文献数
96
被引用文献数
10

Photosynthesis is a biological process of energy conversion from solar radiation to useful organic compounds for the photosynthetic organisms themselves. It, thereby, also plays a role of food production for almost all animals on the Earth. The utilization of photosynthesis as an artificial carbon cycle is also attracting a lot of attention regarding its benefits for human life. Hydrogen and biofuels, obtained from photosynthetic microorganisms, such as microalgae and cyanobacteria, will be promising products as energy and material resources. Considering that the efficiency of bioenergy production is insufficient to replace fossil fuels at present, techniques for the industrial utilization of photosynthesis processes need to be developed intensively. Increase in the efficiency of photosynthesis, the yields of target substances, and the growth rates of algae and cyanobacteria must be subjects for efficient industrialization. Here, we overview the whole aspect of the energy production from photosynthesis to biomass production of various photosynthetic microorganisms.
著者
Akira Yasuda Daichi Inami Mitsumasa Hanaoka
出版者
Applied Microbiology, Molecular and Cellular Biosciences Research Foundation
雑誌
The Journal of General and Applied Microbiology (ISSN:00221260)
巻号頁・発行日
pp.2020.01.010, (Released:2020-04-07)
参考文献数
31
被引用文献数
4

In cyanobacteria, transcription of a set of genes is specifically induced by high-light-stress conditions. In previous studies, RpaB, a response regulator of the two-component system, was shown to be involved in this regulation in vitro and in vivo. In this study, we examined whether RpaB-dependent transcriptional regulation was extensively observed, not only under high-light-stress conditions but also under various light intensities. Transcription of high-light-dependent genes hliA, nblA and rpoD3 was transiently and drastically induced during a dark-to-light shift in a manner similar to high-light-stress responses. Moreover, expression of these genes was activated under various light-intensity upshift conditions. Phos-tag SDS-PAGE experiments showed that the phosphorylation level of RpaB was decreased along with transcriptional induction of target genes in all of the light environments examined herein. These results suggest that RpaB may be widely involved in transcriptional regulation under dark-to-light and light-intensity upshift conditions and that high-light-responsive genes may be required in various light conditions other than high-light condition. Furthermore, it is hypothesised that RpaB is regulated by redox-dependent signals rather than by high-light-stress-dependent signals.
著者
Kazuki Nagata Katsuaki Oyama Atsushi Ota Chihiro Azai Kazuki Terauchi
出版者
Applied Microbiology, Molecular and Cellular Biosciences Research Foundation
雑誌
The Journal of General and Applied Microbiology (ISSN:00221260)
巻号頁・発行日
pp.2020.01.008, (Released:2020-03-30)
参考文献数
31
被引用文献数
3

The cyanobacterial circadian oscillator can be reconstituted by mixing the purified clock proteins KaiA, KaiB, and KaiC with ATP in vitro, leading to a 24-h oscillation of KaiC phosphorylation. The cyanobacterial mutant pr1 carrying valine instead of alanine at position 422 of KaiC (KaiC-A422V) lost the ability to shift the phase of the circadian rhythm. In this study, we analyzed KaiC-A422V to investigate the effect of this single-residue substitution on the in vitro reconstitution of KaiC oscillation. KaiC-A422V exhibited low amplitude oscillations of phosphorylation with a smaller amount of Kai complex than wild-type KaiC (KaiC-WT). Although KaiA can stimulate KaiC phosphorylation, the phosphorylation level of KaiC-A422V is much lower than that of KaiC-WT even at higher KaiA concentrations. It has been suggested that monomer shuffling of KaiC is involved in entraining the in vitro rhythm. To examine whether KaiC-A422V has the capacity for monomer shuffling, we used the difference in the amplitude of the phosphorylation rhythms between KaiC-WT and KaiC-A422V as the indicator of monomer shuffling. When KaiC-A422V and KaiC-WT were mixed, the amplitude of the phosphorylation rhythm changed according to the mixing ratio. This suggests that KaiC-A422V has a reduced ability to shuffle monomers in hexameric KaiC. In addition, the A422V mutation resulted in a change of the stability of the KaiC protein.
著者
Risha M. Patel Mary N. Heneghan Jan A. L. van Kan Andy M. Bailey Gary D. Foster
出版者
公益財団法人 応用微生物学・分子細胞生物学研究奨励会
雑誌
The Journal of General and Applied Microbiology (ISSN:00221260)
巻号頁・発行日
vol.54, no.6, pp.367-376, 2008 (Released:2009-01-23)
参考文献数
41
被引用文献数
3 21

This paper outlines the construction of a novel vector system comprising interchangeable terminators, as well as a multiple cloning site (MCS), to facilitate the transformation of the fungal plant pathogen Botrytis cinerea. Previous molecular studies on B. cinerea have relied upon the pLOB1 based vector system (controlled by the Aspergillus nidulans oliC promoter and a region reported to be the B. cinerea tubA terminator). Investigations, however, have revealed that, rather than the genuine B. cinerea tubA terminator, the pLOB1 terminator fragment is from another gene locus within the genome. Because previous studies have found that terminators aide in transcript stability, the main aims of this study were to develop and evaluate both vector systems, pOT (controlled by the A. nidulans oliC promoter and A. nidulans trpC terminator) and pLOB, with a range of exogenous genes, including enhanced green fluorescent protein (eGFP), monomeric red fluorescent protein (mRFP), luciferase (LUC) and β-glucuronidase (GUS). Our investigations demonstrate that pLOB and pOT based vectors are capable of expressing all four reporter genes and may be applied to future molecular studies on B. cinerea and other related ascomycetes. Additionally, this is the first reported expression of mRFP and LUC in B. cinerea.
著者
Kenta Yonezuka Jun Shimodaira Michiro Tabata Shoko Ohji Akira Hosoyama Daisuke Kasai Atsushi Yamazoe Nobuyuki Fujita Takayuki Ezaki Masao Fukuda
出版者
公益財団法人 応用微生物学・分子細胞生物学研究奨励会
雑誌
The Journal of General and Applied Microbiology (ISSN:00221260)
巻号頁・発行日
pp.2016.06.003, (Released:2016-12-17)
参考文献数
78
被引用文献数
22

Pseudomonas putida is well-known for degradation activities for a variety of compounds and its infections have been reported. Thus, P. putida includes both clinical and nonclinical isolates. To date, no reports have examined the phylogenetic relationship between clinical and nonclinical isolates of the P. putida group. In this study, fifty-nine strains of P. putida group containing twenty-six clinical, and thirty-three nonclinical, isolates, were subjected to phylogenetic and taxonomic analyses based on 16S rRNA gene sequences and nine housekeeping gene sequences, including argS, dnaN, dnaQ, era, gltA, gyrB, ppnK, rpoB, and rpoD, to obtain insights into the diversity of species in this group. More than 97.6% similarity was observed among the 16S rRNA gene sequences of all the strains examined, indicating that the resolution of 16S rRNA gene sequences is inadequate. Phylogenetic analysis based on the individual housekeeping genes listed above improved the resolution of the phylogenetic trees, which are different from each other. Multilocus sequence analysis (MLSA) based on the concatenated sequences of the nine genes significantly improved the resolution of the phylogenetic tree, and yielded approximately the same results as average nucleotide identity (ANI) analysis, suggesting its high reliability. ANI analysis classified the fifty-nine strains into twenty-six species containing seventeen singletons and nine strain clusters based on the 95% threshold. It also indicated the mixed distribution of clinical and nonclinical isolates in the six clusters, suggesting that the genomic difference between clinical and nonclinical isolates of the P. putida group is subtle. The P. putida type strain NBRC 14164T is a singleton that is independently located from the P. putida strains distributed among the six clusters, suggesting that the classification of these strains and the differentiation of species in the P. putida group should be re-examined. This study greatly expands insights into the phylogenetic diversity of the P. putida group.