Publications by authors named "Masaaki Morikawa"

70 Publications

A cyclic lipopeptide surfactin is a species-selective Hsp90 inhibitor that suppresses cyanobacterial growth.

J Biochem 2021 Mar 26. Epub 2021 Mar 26.

Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502, Japan.

Heat shock protein 90 (Hsp90) is essential for eukaryotic cells, whereas bacterial homologs play a role under stresses and in pathogenesis. Identifying species-specific Hsp90 inhibitors is challenging because Hsp90 is evolutionarily conserved. We found that a cyclic lipopeptide surfactin inhibits the ATPase activity of Hsp90 from the cyanobacterium Synechococcus elongatus (S. elongatus) PCC 7942 but does not inhibit Escherichia coli (E. coli), yeast and human Hsp90s. Molecular docking simulations indicated that surfactin could bind to the N-terminal dimerization interface of the cyanobacterial Hsp90 in the ATP- and ADP-bound states, which provided molecular insights into the species-selective inhibition. The data suggest that surfactin inhibits a rate-limiting conformational change of S. elongatus Hsp90 in the ATP hydrolysis. Surfactin also inhibited the interaction of the cyanobacterial Hsp90 with a model substrate, and suppressed S. elongatus growth under heat stress, but not that of E. coli. Surfactin did not show significant cellular toxicity toward mammalian cells. These results indicate that surfactin inhibits the cellular function of Hsp90 specifically in the cyanobacterium. The present study shows that a cyclic peptide has a great specificity to interact with a specific homolog of a highly conserved protein family.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/jb/mvab037DOI Listing
March 2021

Indigenous bacteria, an excellent reservoir of functional plant growth promoters for enhancing duckweed biomass yield on site.

Chemosphere 2021 Apr 7;268:129247. Epub 2020 Dec 7.

Division of Biosphere Science, Graduate School of Environmental Science, Hokkaido University, Kita-10, Nishi-5, Kita-ku, Sapporo, 060-0810, Japan. Electronic address:

The advantages of aquatic biomass production using wastewater as a cost-free fertilizer have recently been highlighted. Here, we report a successful study in which duckweed, Lemna gibba, biomass production in a food factory effluent containing low nitrogen and high salts was enhanced by employing customized plant growth-promoting bacteria (PGPB). Two common PGPB strains previously obtained from natural pond water, Acinetobacter calcoaceticus P23 and Pseudomonas fulva Ps6, hardly promoted the growth of duckweed; on the contrary, they inhibited its growth in treated factory wastewater, far different water conditions. Then, we asked if some indigenous wastewater bacteria could promote the growth of duckweed. We found that Chryseobacterium strains, a group of bacteria with limited nitrogen metabolism, were dominantly selected as effective PGPB. Moreover, we demonstrated that nitrogen limitation is the crucial environmental factor that induces the plant growth-inhibiting behavior of A. calcoaceticus P23 through competition for mineral nutrients with the host duckweed. This study uncovered points to be considered in PGPB technology to achieve efficient production of duckweed biomass in a factory effluent with unbalanced content of mineral nutrients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chemosphere.2020.129247DOI Listing
April 2021

Multiple biosurfactant production by Aureobasidium pullulans strain YTP6-14 in aqueous and heavy oil layers.

J Gen Appl Microbiol 2021 Feb 2;66(6):330-338. Epub 2020 Oct 2.

Department of Microbiology, Chulalongkorn University, Faculty of Science.

Aureobasidium pullulans YTP6-14 was demonstrated to be an excellent multiple biosurfactant producer utilizing cheap carbon sources available in Thailand, including glycerol and cassava flour hydrolysate. A. pullulans YTP6-14 maximally produced 1.81 g/l biosurfactant in an aqueous layer (BS-AQ) in a medium containing glycerol, and 7.37 or 6.37 g/l biosurfactant in a heavy oil layer (BS-HO) in cassava flour hydrolysate or a glucose containing medium, respectively. Each BS-AQ and BS-HO had critical micelle concentration values of 41.32 mg/l and 13.51 mg/l, and both biosurfactants formed a stable food oil emulsion and reduced the amount of biofilms formed by Streptococcus sobrinus and Streptococcus mutans. BS-AQ and BS-HO were mainly composed of liamocins or exophilins and massoia lactone, respectively.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2323/jgam.2020.01.011DOI Listing
February 2021

Community dynamics of duckweed-associated bacteria upon inoculation of plant growth-promoting bacteria.

FEMS Microbiol Ecol 2020 07;96(7)

Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering, Osaka University , 2-1 Suita, Osaka, Japan.

Plant growth-promoting bacteria (PGPB) have recently been demonstrated as a promising agent to improve wastewater treatment and biomass production efficiency of duckweed hydrocultures. With a view to their reliable use in aqueous environments, this study analysed the plant colonization dynamics of PGPB and the ecological consequences for the entire duckweed-associated bacterial community. A PGPB strain, Aquitalea magnusonii H3, was inoculated to duckweed at different cell densities or timings in the presence of three environmental bacterial communities. The results showed that strain H3 improved duckweed growth by 11.7-32.1% in five out of nine experiments. Quantitative-PCR and amplicon sequencing analyses showed that strain H3 successfully colonized duckweed after 1 and 3 d of inoculation in all cultivation tests. However, it significantly decreased in number after 7 d, and similar bacterial communities were observed on duckweed regardless of H3 inoculation. Predicted metagenome analysis suggested that genes related to bacterial chemotactic motility and surface attachment systems are consistently enriched through community assembly on duckweed. Taken together, strain H3 dominantly colonized duckweed for a short period and improved duckweed growth. However, the inoculation of the PGPB did not have a lasting impact due to the strong resilience of the natural duckweed microbiome.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/femsec/fiaa101DOI Listing
July 2020

Biosurfactants from Marine Cyanobacteria Collected in Sabah, Malaysia.

J Nat Prod 2020 06 20;83(6):1925-1930. Epub 2020 May 20.

Institute for Tropical Biology and Conservation, Universiti Malaysia Sabah, Kota Kinabalu 88450, Sabah, Malaysia.

Chemical investigation of the organic extract from , collected in Sabah, Malaysia, led to the isolation of three new chlorinated fatty acid amides, columbamides F (), G (), and H (). The planar structures of - were established by a combination of mass spectrometric and NMR spectroscopic analyses. The absolute configuration of was determined by Marfey's analysis of its hydrolysate and chiral-phase HPLC analysis after conversion and esterification with Ohrui's acid, (1,2)-2-(anthracene-2,3-dicarboximido)cyclohexanecarboxylic acid. Compound showed biosurfactant activity by an oil displacement assay. Related known fatty acid amides columbamide D and serinolamide C exhibited biosurfactant activity with critical micelle concentrations of about 0.34 and 0.78 mM, respectively.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.jnatprod.0c00164DOI Listing
June 2020

Enhanced lipid productivity of Chlamydomonas reinhardtii with combination of NaCl and CaCl stresses.

Bioprocess Biosyst Eng 2020 Jun 1;43(6):971-980. Epub 2020 Feb 1.

Graduate Faculty of Interdisciplinary Research, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi, 400-8511, Japan.

Salinity (NaCl) stress treatment is a strategy to induce lipid accumulation in microalgae. This study aimed to investigate the effect of a combination of two salts (NaCl/CaCl) on lipid productivity of Chlamydomonas reinhardtii. C. reinhardtii was cultured in a two-stage culture comprising 9-day active growth in C medium followed by 3-day salt stress in C medium with various concentrations of NaCl (50‒200 mM)/CaCl (100 mM). In salt stress stage, NaCl (200 mM), CaCl (100 mM), and the NaCl/CaCl mixture inhibited growth but increased the lipid content in C. reinhardtii in comparison with NaCl (0, 50, and 100 mM) conditions. Combinatorial treatment with 100 mM NaCl/100 mM CaCl resulted in the highest lipid content (73.4%) and lipid productivity (10.9 mg/L/days), being 3.5- and 2.1-fold, respectively, in salt-free control conditions, and 1.8- and 1.5-folds, respectively, with 200 mM NaCl. Furthermore, 100 mM NaCl/100 mM CaCl treatment markedly upregulated glycerol-3-phosphate dehydrogenase (GPDH), lysophosphatidic acid acyltransferase (LPAAT), and diacylglycerol acyltransferase (DAGAT), which are involved in lipid accumulation in C. reinhardtii. The upregulation of these genes with 100 mM NaCl/100 mM CaCl resulted in the highest lipid content in C. reinhardtii. Therefore, stress treatment using two salts, 100 mM NaCl/100 mM CaCl, is a potentially promising strategy to enhance lipid productivity in microalgae.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00449-020-02293-wDOI Listing
June 2020

Enhanced production of biomass and lipids by via co-culturing with a microalga growth-promoting bacterium, sp. EG3.

Biotechnol Biofuels 2019 31;12:205. Epub 2019 Oct 31.

1Graduate Faculty of Interdisciplinary Research, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi 400-8511 Japan.

Background: , a unicellular flagellated microalga, is regarded as one of the most promising species as microalgal feedstock for biofuels. Its lipids (mainly wax esters) are suitable for biodiesel and jet fuel. Culture of using wastewater effluent will improve the economics of biofuel production. Enhancement of the productivity of biomass is critical to creating a highly efficient biofuels production system. Certain bacteria have been found to promote microalgal growth by creating a favorable microenvironment. These bacteria have been characterized as microalgae growth-promoting bacteria (MGPB). Co-culture of microalgae with MGPB might offer an effective strategy to enhance microalgal biomass production in wastewater effluent culture systems. However, no MGPB has been identified to enhance the growth of . The objectives of this study were, therefore, to isolate and characterize the MGPB effective for and to demonstrate that the isolated MGPB indeed enhances the production of biomass and lipids by in wastewater effluent culture system.

Results: A bacterium, sp. EG3, which is capable of promoting the growth of microalga , was isolated from an -municipal wastewater effluent culture. Biomass production rate of was enhanced 3.5-fold and 3.1-fold by EG3 in the co-culture system using a medium of heat-sterilized and non-sterilized wastewater effluent, respectively, compared to growth in the same effluent culture but without EG3. Two-step culture system was examined as follows: was cultured with or without EG3 in wastewater effluent in the first step and was further grown in wastewater effluent in the second step. Production yields of biomass and lipids by were enhanced 3.2-fold and 2.9-fold, respectively, in the second step of the system in which was co-cultured with EG3 in the first step.

Conclusion: sp. EG3 is the first MGPB for . Growth-promoting bacteria such as EG3 will be promising agents for enhancing biomass/biofuel productivities.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13068-019-1544-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6822413PMC
October 2019

Enhanced biomass production and nutrient removal capacity of duckweed via two-step cultivation process with a plant growth-promoting bacterium, Acinetobacter calcoaceticus P23.

Chemosphere 2020 Jan 27;238:124682. Epub 2019 Aug 27.

Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan. Electronic address:

Plant growth-promoting bacteria (PGPB) are considered a promising tool to improve biomass production and water remediation by the aquatic plant, duckweed; however, no effective methodology is available to utilize PGPB in large hydroponic systems. In this study, we proposed a two-step cultivation process, which comprised of a "colonization step" and a "mass cultivation step," and examined its efficacy in both bucket-scale and flask-scale cultivation experiments. We showed that in the outdoor bucket-scale experiments using three kinds of environmental water, plants cultured through the two-step cultivation method with the PGPB strain, Acinetobacter calcoaceticus P23, yielded 1.9 to 2.3 times more biomass than the control (without PGPB inoculation). The greater nitrogen and phosphorus removals compared to control were also attained, indicating that this strategy is useful for accelerating nutrient removal by duckweed. Flask-scale experiments using non-sterile pond water revealed that inoculation of strain P23 altered duckweed surface microbial community structures, and the beneficial effects of the inoculated strain P23 could last for 5-10 d. The loss of the duckweed growth-promoting effect was noticeable when the colonization of strain P23 decreased in the plant. These observations suggest that the stable colonization of the plant with PGPB is the key for maintaining the accelerated duckweed growth and nutrient removal in this cultivation method. Overall, our results suggest the possibility of an improved duckweed production using a two-step cultivation process with PGPB.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chemosphere.2019.124682DOI Listing
January 2020

Colonization and Competition Dynamics of Plant Growth-Promoting/Inhibiting Bacteria in the Phytosphere of the Duckweed Lemna minor.

Microb Ecol 2019 Feb 2;77(2):440-450. Epub 2019 Jan 2.

Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.

Despite the considerable role of aquatic plant-associated bacteria in host plant growth and nutrient cycling in aquatic environments, the mode of their plant colonization has hardly been understood. This study examined the colonization and competition dynamics of a plant growth-promoting bacterium (PGPB) and two plant growth-inhibiting bacteria (PGIB) in the aquatic plant Lemna minor (common duckweed). When inoculated separately to L. minor, each bacterial strain quickly colonized at approximately 10 cells per milligram (plant fresh weight) and kept similar populations throughout the 7-day cultivation time. The results of two-membered co-inoculation assays revealed that the PGPB strain Aquitalea magnusonii H3 consistently competitively excluded the PGIB strain Acinetobacter ursingii M3, and strain H3 co-existed at almost 1:1 proportion with another PGIB strain, Asticcacaulis excentricus M6, regardless of the inoculation ratios (99:1-1:99) and inoculation order. We also found that A. magnusonii H3 exerted its growth-promoting effect over the negative effects of the two PGIB strains even when only a small amount was inoculated, probably due to its excellent competitive colonization ability. These experimental results demonstrate that there is a constant ecological equilibrium state involved in the bacterial colonization of aquatic plants.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00248-018-1306-xDOI Listing
February 2019

Effect of Exogenous General Plant Growth Regulators on the Growth of the Duckweed .

Front Chem 2018 9;6:251. Epub 2018 Jul 9.

Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan.

Gibberellic acid (GA), indole-3-acetic acid (IAA), salicylic acid (SA), abscidic acid (ABA), jasmonic acid (JA) 1-amino cyclopropane-1-carboxylic acid (ACC) and aminoethoxyvinylglycine (AVG) are popular growth regulators of plants. However, the effects of their exogenous addition on the biomass production of aquatic plants, including plants, "duckweeds," are largely unknown. In this study, the growth of was tested for 10 d in Hoagland medium containing each compound at different concentrations of 0-50 μM. GA, IAA, and SA were found to have no apparent positive effect on the growth at all concentrations tested. Conversely, ACC and JA moderately and AVG and ABA severely inhibited the growth of . Among the tested compounds, ascorbic acid had an apparent growth-promoting effect.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fchem.2018.00251DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6046615PMC
July 2018

Growth promotion of three microalgae, , and , by in situ indigenous bacteria in wastewater effluent.

Biotechnol Biofuels 2018 25;11:176. Epub 2018 Jun 25.

1Graduate Faculty of Interdisciplinary Research, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi 400-8511 Japan.

Background: Microalgae are a promising biomass feedstock for biofuels production. The use of wastewater effluent as a nutrient medium would improve the economics of microalgal biofuels production. Bacterial communities in aquatic environments may either stimulate or inhibit microalgal growth. Microalgal productivity could be enhanced if the positive effects of indigenous bacteria could be exploited. However, much is unknown about the effects of indigenous bacteria on microalgal growth and the characteristics of bacterial communities associated with microalgae in microalgae-effluent culture. To assess the effects of the indigenous bacteria in wastewater effluent on microalgal growth, three microalgae, , , and , were cultured in two municipal wastewater effluents and one swine wastewater effluent with and without indigenous bacteria for 7 days.

Results: All microalgae grew better in all effluents with indigenous bacteria than without bacteria. Biomass production of , , and increased > 1.5, 1.8-2.8, and > 2.1-fold, respectively, compared to the axenic cultures of each microalga. The in situ indigenous bacterial communities in the effluents therefore promoted the growth of the three microalgae during 7-day cultures. Furthermore, the total numbers of bacterial 16S rRNA genes in the 7-day microalgae-effluent cultures were 109‒793 times the initial numbers. These results suggest that the three microalgae produced and supplied organic carbon that supported bacterial growth in the effluent. At the phylum and class levels, ( and ) and ( and ) were selectively enriched in all microalgae-effluent cultures. The enriched core bacterial families and genera were functions of the microalgal species and effluents. These results suggest that certain members of the bacterial community promote the growth of their "host" microalgal species.

Conclusion: To enhance their own growth, microalgae may be able to selectively stimulate specific bacterial groups from among the in situ indigenous bacterial community found in wastewater effluent (i.e., microalgae growth-promoting bacteria: MGPB). The MGPB from effluent cultures could be used as "probiotics" to enhance microalgal growth in effluent culture. Wastewater effluent may therefore be a valuable resource, not only of nutrients, but also of MGPB to enable more efficient microalgal biomass production.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13068-018-1174-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6016138PMC
June 2018

Comprehensive evaluation of nitrogen removal rate and biomass, ethanol, and methane production yields by combination of four major duckweeds and three types of wastewater effluent.

Bioresour Technol 2018 Feb 24;250:464-473. Epub 2017 Nov 24.

Graduate Faculty of Interdisciplinary Research, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi 400-8511, Japan.

To assess the potential of duckweeds as agents for nitrogen removal and biofuel feedstocks, Spirodela polyrhiza, Lemna minor, Lemna gibba, and Landoltia punctata were cultured in effluents of municipal wastewater, swine wastewater, or anaerobic digestion for 4 days. Total dissolved inorganic nitrogen (T-DIN) of 20-50 mg/L in effluents was effectively removed by inoculating with 0.3-1.0 g/L duckweeds. S. polyrhiza showed the highest nitrogen removal (2.0-10.8 mg T-DIN/L/day) and biomass production (52.6-70.3 mg d.w./L/day) rates in all the three effluents. Ethanol and methane were produced from duckweed biomass grown in each effluent. S. polyrhiza and L. punctata biomass showed higher ethanol (0.168-0.191, 0.166-0.172 and 0.174-0.191 g-ethanol/g-biomass, respectively) and methane (340-413 and 343-408 NL CH/kg VS, respectively) production potentials than the others, which is related to their higher carbon and starch contents and calorific values.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.biortech.2017.11.054DOI Listing
February 2018

Differential oxidative and antioxidative response of duckweed Lemna minor toward plant growth promoting/inhibiting bacteria.

Plant Physiol Biochem 2017 Sep 9;118:667-673. Epub 2017 Aug 9.

Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan. Electronic address:

Bacteria colonizing the plant rhizosphere are believed to positively or negatively affect the host plant productivity. This feature has inspired researchers to engineer such interactions to enhance crop production. However, it remains to be elucidated whether rhizobacteria influences plant oxidative stress vis-a-vis other environmental stressors, and whether such influence is associated with their growth promoting/inhibiting ability. In this study, two plant growth-promoting bacteria (PGPB) and two plant growth-inhibiting bacteria (PGIB) were separately inoculated into axenic duckweed (Lemna minor) culture under laboratory conditions for 4 and 8 days in order to investigate their effects on plant oxidative stress and antioxidant activities. As previously characterized, the inoculation of PGPB and PGIB strains accelerated and reduced the growth of L. minor, respectively. After 4 and 8 days of cultivation, compared to the PGPB strains, the PGIB strains induced larger amounts of O, HO, and malondialdehyde (MDA) in duckweed, although all bacterial strains consistently increased O content by two times more than that in the aseptic control plants. Activities of five antioxidant enzymes were also elevated by the inoculation of PGIB, confirming the severe oxidative stress condition in plants. These results suggest that the surface attached bacteria affect differently on host oxidative stress and its response, which degree correlates negatively to their effects on plant growth.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.plaphy.2017.08.006DOI Listing
September 2017

Evaluation of environmental bacterial communities as a factor affecting the growth of duckweed .

Biotechnol Biofuels 2017 10;10:62. Epub 2017 Mar 10.

Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871 Japan.

Background: Duckweed (family ) has recently been recognized as an ideal biomass feedstock for biofuel production due to its rapid growth and high starch content, which inspired interest in improving their productivity. Since microbes that co-exist with plants are known to have significant effects on their growth according to the previous studies for terrestrial plants, this study has attempted to understand the plant-microbial interactions of a duckweed, , focusing on the growth promotion/inhibition effects so as to assess the possibility of accelerated duckweed production by modifying co-existing bacterial community.

Results: Co-cultivation of aseptic and bacterial communities collected from various aquatic environments resulted in changes in duckweed growth ranging from -24 to +14% compared to aseptic control. A number of bacterial strains were isolated from both growth-promoting and growth-inhibitory communities, and examined for their co-existing effects on duckweed growth. Irrespective of the source, each strain showed promotive, inhibitory, or neutral effects when individually co-cultured with . To further analyze the interactions among these bacterial strains in a community, binary combinations of promotive and inhibitory strains were co-cultured with aseptic , resulting in that combinations of promotive-promotive or inhibitory-inhibitory strains generally showed effects similar to those of individual strains. However, combinations of promotive-inhibitory strains tended to show inhibitory effects while only H3 exerted its plant growth-promoting effect in all combinations tested.

Conclusion: Significant change in biomass production was observed when duckweed was co-cultivated with environmental bacterial communities. Promotive, neutral, and inhibitory bacteria in the community would synergistically determine the effects. The results indicate the possibility of improving duckweed biomass production via regulation of co-existing bacterial communities.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13068-017-0746-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5345205PMC
March 2017

Wewakazole B, a Cytotoxic Cyanobactin from the Cyanobacterium Moorea producens Collected in the Red Sea.

J Nat Prod 2016 Apr 16;79(4):1213-8. Epub 2016 Mar 16.

Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry , Abiko 270-1194, Japan.

A mass spectrometry (MS)-guided isolation has led to the purification of a new cyanobactin, wewakazole B (1), along with the known compound curacin D from a Red Sea Moorea producens. The planar structure of 1 was elucidated using a combination of NMR and MS techniques. After ozonolysis and acid hydrolysis, the absolute configurations of the amino acid components of 1 were determined by chiral-phase LC-MS and HPLC analyses. Notably, compound 1 exhibited cytotoxic activity toward human MCF7 breast cancer cells (IC50 = 0.58 μM) and human H460 lung cancer cells (IC50 = 1.0 μM) and was also found to be inactive in a siderophore assay.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.jnatprod.6b00051DOI Listing
April 2016

Draft Genome Sequence of Acinetobacter calcoaceticus Strain P23, a Plant Growth-Promoting Bacterium of Duckweed.

Genome Announc 2015 Feb 26;3(1). Epub 2015 Feb 26.

Biological Resource Center, National Institute of Technology and Evaluation, Tokyo, Japan.

Acinetobacter calcoaceticus strain P23 is a plant growth-promoting bacterium, which was isolated from the surface of duckweed. We report here the draft genome sequence of strain P23. The genome data will serve as a valuable reference for understanding the molecular mechanism of plant growth promotion in aquatic plants.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/genomeA.00026-15DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4342421PMC
February 2015

Isolation and characterization of an early colonizing Rhizobium sp. R8 from a household toilet bowl.

Biosci Biotechnol Biochem 2015 24;79(7):1207-15. Epub 2015 Feb 24.

a Graduate School of Environmental Science , Hokkaido University , Sapporo 060-0810 , Japan.

The bacterial community structure was compared between the third days', one week', and three weeks' biofilm samples from the surface of a household toilet bowl. It was found that the PCR-DGGE band pattern of 16S rRNA gene was dramatically changed after the third day and was not further changed until three weeks. This result suggests that there are early and late colonizing bacterial groups. One of the early colonizers isolated from the third days' sample was Rhizobium sp. R8, a closest relative to Rhizobium giardinii, which exhibited the highest biofilm formation activity in an artificial urine condition. R8 produced extracellular polysaccharides containing galactose, glucose, and mannose at the molar ratio of 8:1:1, which were probably responsible for the biofilm formation. Its excelled biofilm formation and urease activities together with the lack of nodulation and nitrogen fixing genes in R8 suggest that this strain has been specifically adapted to urine condition in a toilet bowl.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/09168451.2015.1012151DOI Listing
May 2016

cDNA cloning and characterization of vanadium-dependent bromoperoxidases from the red alga Laurencia nipponica.

Biosci Biotechnol Biochem 2014 17;78(8):1310-9. Epub 2014 Jun 17.

a Graduate School of Environmental Science , Hokkaido University , Sapporo , Japan.

The marine red alga genus Laurencia is one of the richest producers of unique brominated compounds in the marine environment. The cDNAs for two Laurencia nipponica vanadium-dependent bromoperoxidases (LnVBPO1 and LnVBPO2) were cloned and expressed in Escherichia coli. Enzyme assays of recombinant LnVBPO1 and LnVBPO2 using monochlorodimedone revealed that they were thermolabile but their Km values for Br(-) were significantly lower than other red algal VBPOs. The bromination reaction was also assessed using laurediol, the predicted natural precursor of the brominated ether laurencin. Laurediol, protected by trimethylsilyl at the enyne, was converted to deacetyllaurencin by the LnVBPOs, which was confirmed by tandem mass spectrometry. Native LnVBPO partially purified from algal bodies was active, suggesting that LnVBPO is functional in vivo. These results contributed to our knowledge of the biosynthesis of Laurencia brominated metabolites.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/09168451.2014.918482DOI Listing
April 2015

Cloning and expression of three ladA-type alkane monooxygenase genes from an extremely thermophilic alkane-degrading bacterium Geobacillus thermoleovorans B23.

Extremophiles 2014 May 30;18(3):515-23. Epub 2014 Mar 30.

Division of Biosphere Science, Graduate School of Environmental Science, Hokkaido University, Sapporo, 060-0810, Japan.

An extremely thermophilic bacterium, Geobacillus thermoleovorans B23, is capable of degrading a broad range of alkanes (with carbon chain lengths ranging between C11 and C32) at 70 °C. Whole-genome sequence analysis revealed that unlike most alkane-degrading bacteria, strain B23 does not possess an alkB-type alkane monooxygenase gene. Instead, it possesses a cluster of three ladA-type genes, ladAαB23, ladAβB23, and ladB B23, on its chromosome, whose protein products share significant amino acid sequence identities, 49.8, 34.4, and 22.7 %, respectively, with that of ladA alkane monooxygenase gene found on a plasmid of Geobacillus thermodetrificans NG 80-2. Each of the three genes, ladAαB23, ladAβB23, and ladB B23, was heterologously expressed individually in an alkB1 deletion mutant strain, Pseudomonas fluorescens KOB2Δ1. It was found that all three genes were functional in P. fluorescens KOB2Δ1, and partially restored alkane degradation activity. In this study, we suggest that G. thermoleovorans B23 utilizes multiple LadA-type alkane monooxygenases for the degradation of a broad range of alkanes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00792-014-0636-yDOI Listing
May 2014

Transformation of iso-pentylbenzene by a biofilm-forming strain of Candida viswanathii TH1 isolated from oil-polluted sediments collected in coastal zones in Vietnam.

J Environ Sci Health A Tox Hazard Subst Environ Eng 2014 ;49(7):777-86

a Institute of Biotechnology , Vietnam Academy of Science and Technology , Cau Giay , Hanoi , Vietnam.

This work is aimed to assess the aerobic biotransformation of a branched side chain alkylbenzene, iso-pentylbenzene, by Candida viswanathii TH1. The yeast Candida viswanathii TH1 isolated from oil-polluted sediments collected in coastal zones in Vietnam exhibited as a strain that could better transform branched aromatic hydrocarbons in biofilm (pellicle) than in planktonic form. During incubation of TH1 as biofilm with iso-pentylbenzene, the seven intermediates produced were benzoic acid, phenylacetic acid, 2-methyl-4-phenyl-butan-1-ol, 2-hydroxy-phenylacetic acid, 2-methyl-4-phenylbutyric acid, succinic acid and iso-valerophenone as revealed by gas chromatography/mass spectra and high-performance liquid chromatography analyses. The occurrence of these intermediates showed that iso-pentylbenzene could be oxidized not only via mono- but also by a sub-terminal oxidation pathway. This is the first study on iso-pentylbenzene transformation by a biofilm-forming Candida viswanathii strain. The catabolic versatility of the biofilm-forming strain TH1 and its use for mono and sub-terminal oxidation during the transformation of iso-pentylbenzene enhance our understanding of the degradation of branched side chain phenylalkanes and give new insight into the potential role of such species in the transformation of other recalcitrant aromatic compounds.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/10934529.2014.882202DOI Listing
December 2014

Plant growth-promoting bacterium Acinetobacter calcoaceticus P23 increases the chlorophyll content of the monocot Lemna minor (duckweed) and the dicot Lactuca sativa (lettuce).

J Biosci Bioeng 2014 Jul 24;118(1):41-4. Epub 2014 Jan 24.

Graduate School of Environmental Science, Hokkaido University, N10-W5, Kita-ku, Sapporo 060-0810, Japan; Advanced Low Carbon Technology Research and Development Program (ALCA), Department of Green Innovation, Japan Science and Technology Agency, K's Gobancho, Chiyoda-ku, Tokyo 102-0076, Japan. Electronic address:

Acinetobacter calcoaceticus P23 is a plant growth-promoting bacterium that was isolated from the surface of duckweed (Lemna aoukikusa). The bacterium was observed to colonize on the plant surfaces and increase the chlorophyll content of not only the monocotyledon Lemna minor but also the dicotyledon Lactuca sativa in a hydroponic culture. This effect on the Lactuca sativa was significant in nutrient-poor (×1/100 dilution of H2 medium) and not nutrient-rich (×1 or ×1/10 dilutions of H2 medium) conditions. Strain P23 has the potential to play a part in the future development of fertilizers and energy-saving hydroponic agricultural technologies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jbiosc.2013.12.007DOI Listing
July 2014

Production and characterization of a biosurfactant from Cyberlindnera samutprakarnensis JP52(T.).

Biosci Biotechnol Biochem 2013 7;77(12):2362-70. Epub 2013 Dec 7.

Department of Microbiology, Faculty of Science, Chulalongkorn University.

Cyberlindnera samutprakarnensis JP52(T), isolated from cosmetic industrial wastes in Thailand, was found to be an efficient biosurfactant-producing yeast when cultured in a medium containing (2% (w/v) glucose and 2% (v/v) palm oil at 30 °C, 200 rpm for 7 d. The crude biosurfactant had the ability to reduce the surface tension from 55.7 to 30.9 mN/m at 25 °C with a critical micelle concentration (CMC) of 0.046%. Physicochemical analysis of the crude biosurfactant revealed that it had wide ranges of optimum pH and pH stability at 6-9 and 3-10 respectively. It was also thermostable and retained 80% activity even after heat treatment, and it tolerated NaCl at 1.0-10%. Furthermore, it effectively emulsified various vegetable oils with an E24 value of over 80%. A partially purified biosurfactant fraction was analyzed for its structure by MALDI-TOF MS and NMR. This revealed that the biosurfactant mainly contained sophorolipids in C18-(MW 574) and C16-diaceltylated (MW 662) forms.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1271/bbb.130434DOI Listing
August 2014

Isolation and characterization of a thermotolerant ammonia-oxidizing bacterium Nitrosomonas sp. JPCCT2 from a thermal power station.

Microbes Environ 2013 19;28(4):432-5. Epub 2013 Nov 19.

Division of Biosphere Science, Graduate School of Environmental Science, Hokkaido University.

A thermotolerant ammonia-oxidizing bacterium strain JPCCT2 was isolated from activated sludge in a thermal power station. Cells of JPCCT2 are short non-motile rods or ellipsoidal. Molecular phylogenetic analysis of 16S rRNA gene sequences demonstrated that JPCCT2 belongs to the genus Nitrosomonas with the highest similarity to Nitrosomonas nitrosa Nm90 (100%), Nitrosomonas sp. Nm148 (99.7%), and Nitrosomonas communis Nm2 (97.7%). However, G+C content of JPCCT2 DNA was 49.1 mol% and clearly different from N. nitrosa Nm90, 47.9%. JPCCT2 was capable of growing at temperatures up to 48 °C, while N. nitrosa Nm90 and N. communis Nm2 could not grow at 42°C. Moreover, JPCCT2 grew similarly at concentrations of carbonate 0 and 5 gL(-1). This is the first report that Nitrosomonas bacterium is capable of growing at temperatures higher than 37°C.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4070699PMC
http://dx.doi.org/10.1264/jsme2.me13058DOI Listing
July 2014

Draft Genome Sequence of Geobacillus thermoleovorans Strain B23.

Genome Announc 2013 Nov 14;1(6). Epub 2013 Nov 14.

Division of Biosphere Science, Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan.

Here, we report the draft genome sequence of Geobacillus thermoleovorans strain B23, which was isolated from a deep subterranean petroleum reservoir in Japan. An array of genes related to unique long-chain alkane degradation pathways in G. thermoleovorans B23 has been identified by whole-genome analyses of this strain.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/genomeA.00944-13DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3828315PMC
November 2013

Efficacy of forming biofilms by naphthalene degrading Pseudomonas stutzeri T102 toward bioremediation technology and its molecular mechanisms.

Chemosphere 2012 Apr 28;87(3):226-33. Epub 2012 Jan 28.

Division of Biosphere Science, Graduate School of Environmental Science, Hokkaido University, N-10 W-5, Kita-ku, Sapporo, 060-0810 Hokkaido, Japan.

In natural environments, bacteria often exist in close association with surfaces and interfaces. There they form "biofilms", multicellular aggregates held together by an extracellular matrix. The biofilms confer on the constituent cells high resistance to environmental stresses and diverse microenvironments that help generate cellular heterogeneity. Here we report on the ability of Pseudomonas stutzeri T102 biofilm-associated cells, as compared with that of planktonic cells, to degrade naphthalene and survive in petroleum-contaminated soils. In liquid culture system, T102 biofilm-associated cells did not degrade naphthalene during initial hours of incubation but then degraded it faster than planktonic cells, which degraded naphthalene at a nearly constant rate. This delayed but high degradation activity of the biofilms could be attributed to super-activated cells that were detached from the biofilms. When the fitness of T102 biofilm-associated cells was tested in natural petroleum-contaminated soils, they were capable of surviving for 10 wk; by then T102 planktonic cells were mostly extinct. Naphthalene degradation activity in the soils that had been inoculated with T102 biofilms was indeed higher than that observed in soils inoculated with T102 planktonic cells. These results suggest that inoculation of contaminated soils with P. stutzeri T102 biofilms should enable bioaugmentation to be a more durable and effective bioremediation technology than inoculation with planktonic cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chemosphere.2011.12.078DOI Listing
April 2012

A truncated form of SpoT, including the ACT domain, inhibits the production of cyclic lipopeptide arthrofactin, and is associated with moderate elevation of guanosine 3',5'-bispyrophosphate level in Pseudomonas sp. MIS38.

Biosci Biotechnol Biochem 2011 7;75(10):1880-8. Epub 2011 Oct 7.

Division of Biosphere Science, Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan.

Arthrofactin is a biosurfactant produced by Pseudomonas sp. MIS38. We have reported that transposon insertion into spoT (spoT::Tn5) causes moderate accumulation of guanosine 3',5'-bispyrophosphate (ppGpp) and abrogates arthrofactin production. To analyze the linkage of SpoT function and ablation of arthrofactin production, we examined the spoT::Tn5 mutation. The results showed that spoT::Tn5 is not a null mutation, but encodes separate segments of SpoT. Deletion of the 3' region of spoT increased the level of arthrofactin production, suggesting that the C-terminal region of SpoT plays a suppressive role. We evaluated the expression of a distinct segment of SpoT. Forced expression of the C-terminal region that contains the ACT domain resulted in the accumulation of ppGpp and abrogated arthrofactin production. Expression of the C-terminal segment also reduced MIS38 swarming and resulted in extensive biofilm formation, which constitutes the phenocopy of the spoT::Tn5 mutant.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1271/bbb.110042DOI Listing
February 2012

Diversity of nonribosomal peptide synthetases involved in the biosynthesis of lipopeptide biosurfactants.

Int J Mol Sci 2010 Dec 30;12(1):141-72. Epub 2010 Dec 30.

Microbial Cell Factory Laboratory, Bioresources Technology Unit, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathumthani 12120, Thailand.

Lipopeptide biosurfactants (LPBSs) consist of a hydrophobic fatty acid portion linked to a hydrophilic peptide chain in the molecule. With their complex and diverse structures, LPBSs exhibit various biological activities including surface activity as well as anti-cellular and anti-enzymatic activities. LPBSs are also involved in multi-cellular behaviors such as swarming motility and biofilm formation. Among the bacterial genera, Bacillus (Gram-positive) and Pseudomonas (Gram-negative) have received the most attention because they produce a wide range of effective LPBSs that are potentially useful for agricultural, chemical, food, and pharmaceutical industries. The biosynthetic mechanisms and gene regulation systems of LPBSs have been extensively analyzed over the last decade. LPBSs are generally synthesized in a ribosome-independent manner with megaenzymes called nonribosomal peptide synthetases (NRPSs). Production of active-form NRPSs requires not only transcriptional induction and translation but also post-translational modification and assemblage. The accumulated knowledge reveals the versatility and evolutionary lineage of the NRPSs system. This review provides an overview of the structural and functional diversity of LPBSs and their different biosynthetic mechanisms in Bacillus and Pseudomonas, including both typical and unique systems. Finally, successful genetic engineering of NRPSs for creating novel lipopeptides is also discussed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ijms12010141DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3039948PMC
December 2010

Sustainable biodegradation of phenol by Acinetobacter calcoaceticus P23 isolated from the rhizosphere of duckweed Lemna aoukikusa.

Environ Sci Technol 2010 Aug;44(16):6470-4

Division of Biosphere Science, Graduate School of Environmental Science, Hokkaido University, Kita-10, Nishi-5, Kita-ku, Sapporo 060-0810, Japan.

Phenol-degrading bacteria were isolated from the rhizosphere of duckweed (Lemna aoukikusa) using an enrichment culture method. One of the isolates, P23, exhibited an excellent ability to degrade phenol and attach to a solid surface under laboratory conditions. Phylogenetic analysis revealed that P23 belongs to the genera Acinetobacter and has the highest similarity to Acinetobacter calcoaceticus. P23 rapidly colonized on the surface of sterilized duckweed roots and formed biofilms, indicating that the conditions provided by the root system of duckweed are favorable to P23. A long-term performance test (160 h) showed that continuous removal of phenol can be attributed to the beneficial symbiotic interaction between duckweed and P23. P23 is the first growth-promoting bacterium identified from Lemna aoukikusa. The results in this study suggest the potential usefulness of dominating a particular bacterium in the rhizosphere of duckweeds to achieve efficient and sustainable bioremediation of polluted water.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/es1007017DOI Listing
August 2010

Dioxygen activation responsible for oxidation of aliphatic and aromatic hydrocarbon compounds: current state and variants.

Authors:
Masaaki Morikawa

Appl Microbiol Biotechnol 2010 Aug 18;87(5):1595-603. Epub 2010 Jun 18.

Section of Environmental Biology,Faculty of Environmental Earth Science, Hokkaido University, Sapporo 060-0810, Japan.

The most significant aspect in microbial metabolisms, especially those of bacteria and archaea, is their marvelously wide acceptability of substrate electron donors and acceptors. This feature makes them to be attractive catalysts for environmental biotechnology in terms of degradation of harmful recalcitrant compounds, including hydrocarbons. Transformation of highly reduced and inert hydrocarbon compounds is with no doubt a challenging biochemical reaction for a single enzyme. However, several multi-component enzyme systems enable microorganisms to utilize hydrocarbons as carbon and energy (electron) sources. Initial biological attack to hydrocarbons is, in most cases, the hydroxylation that requires molecular dioxygen as a co-substrate. Dioxygen also contributes to the ring cleavage reaction of homo- and hetero-cyclic aromatic hydrocarbons. Although the molecular dioxygen is omnipresent and highly soluble in water, activation and splitting this triplet ground-state molecule to wed with difficult hydrocarbons need special devices. Non-heme iron, heme iron, or flavin nucleotide was designated as a major hidden dagger for this purpose.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00253-010-2715-zDOI Listing
August 2010

Identification and characterization of the genes responsible for the production of the cyclic lipopeptide arthrofactin by Pseudomonas sp. MIS38.

Biosci Biotechnol Biochem 2010 7;74(5):992-9. Epub 2010 May 7.

Division of Biosphere Science, Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan.

Pseudomonas sp. MIS38 produces an effective biosurfactant named arthrofactin, which is a cyclic lipopeptide synthesized by a mega complex composed of three nonribosomal peptide synthetases. In order to gain insight into the control mechanism of arthrofactin production, a Tn5 mutant library was constructed and screened for arthrofactin-deficient mutants. Along with a number of mutations that occurred in the arthrofactin synthetase operon, three other mutants harbored distinct Tn5 insertions in the genes encoding SyrF-like protein (arfF), heat shock protein (htpG), and (p)ppGpp synthetase/hydrolase (spoT). Epistasis analyses revealed that spoT functions early in the arthrofactin production pathway. We also found that spoT affects MIS38 swarming, biofilm formation, and the cell morphology.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1271/bbb.90860DOI Listing
September 2010