Genome Sequencing Unveils Nomadic Traits of Lactiplantibacillus plantarum in Japanese Post-Fermented Tea.

Post-fermented tea production involving microbial fermentation is limited to a few regions, such as Southeast Asia and Japan, with Japan's Shikoku island being particularly prominent. Lactiplantibacillus plantarum was the dominant species found in tea leaves after anaerobic fermentation of Awa-bancha in Miyoshi City, Tokushima, and Ishizuchi-kurocha in Ehime. Although the draft genome of L. plantarum from Japanese post-fermented tea has been previously reported, its genetic diversity requires further exploration. In this study, whole-genome sequencing was conducted on four L. plantarum strains isolated from Japanese post-fermented tea using nanopore sequencing. These isolates were then compared with other sources to examine their genetic diversity revealing that L. plantarum isolated from Japanese post-fermented tea contained several highly variable gene regions associated with sugar metabolism and transportation. However, no source-specific genes or clusters were identified within accessory or core gene regions. This study indicates that L. plantarum possesses high genetic diversity and that the unique environment of Japanese post-fermented tea does not appear to exert selective pressure on L. plantarum growth.

Variations in fungal and bacterial microbiome and chemical composition among fermenting Kishu-Narezushi batches.

Kishu-Narezushi is a spontaneously fermented food comprising fish, rice, and salt. During spontaneous fermentation, the microbiome may differ among batches, even when manufactured in the same way. In addition, analyses of changes in the chemical composition of the product are important for clarifying flavor characteristics. We collected basic information on the microbiome and chemical composition of Kishu-Narezushi using multiple batches of fermentation and evaluated whether the microbiome was homogeneous. The fungal microbiome of Kishu-Narezushi was dominated by Saccharomycetales and Trichosporonales. The bacterial microbiome was diverse, although seven specific genera of lactic acid bacteria were identified. Glutamic acid, histidine, and serine levels decreased after ∼10 days of fermentation. Succinic acid, characteristic of Kishu-Narezushi, accumulated upon the consumption of glutamic acid. Though the microbiome was diverse, the chemical composition was similar among the batches.

Controlling the microbial composition during the fermentation of Ishizuchi-kurocha.

Ishizuchi-kurocha is a popular postfermented tea in Japan. It is performed by domestic and natural fermentation relied on microorganisms derived from tea leaves or the environment of the manufacturing. Ishizuchi-kurocha undergoes aerobic fermentation of fungi first, then second fermented by anaerobic fermentation of lactic acid bacteria during natural fermentation processing. Aspergillus niger that produces mycotoxin is included in natural fermentation. This research aimed to build a novel fermentation method of Ishizuchi-kurocha by adding industrial koji fungi products and laboratory-cultivated Lactobacillus plantarum (Lactiplantibacillus plantarum) artificially. Thus, safety and quality of tea products could be controlled simply. We found artificial fermentation of Ishizuchi-kurocha could get high lactic acid production within 8 days. Final products only consisted of genus Aspergillus and genus Lactobacillus, while harmful Aspergillus niger was not found. However, artificial fermentation methods also decreased the content of polyphenols when compared with commercial tea.

In Vivo Study of the Efficacy and Safety of 5-Aminolevulinic Radiodynamic Therapy for Glioblastoma Fractionated Radiotherapy.

To treat malignant glioma, standard fractionated radiotherapy (RT; 60 Gy/30 fractions over 6 weeks) was performed post-surgery in combination with temozolomide to improve overall survival. Malignant glioblastoma recurrence rate is extremely high, and most recurrent tumors originate from the excision cavity in the high-dose irradiation region. In our previous study, protoporphyrin IX physicochemically enhanced reactive oxygen species generation by ionizing radiation and combined treatment with 5-aminolevulinic acid (5-ALA) and ionizing radiation, while radiodynamic therapy (RDT) improved tumor growth suppression in vivo in a melanoma mouse model. We examined the effect of 5-ALA RDT on the standard fractionated RT protocol using U251MG- or U87MG-bearing mice. 5-ALA was orally administered at 60 or 120 mg/kg, 4 h prior to irradiation. In both models, combined treatment with 5-ALA slowed tumor progression and promoted regression compared to treatment with ionizing radiation alone. The standard fractionated RT protocol of 60 Gy in 30 fractions with oral administration of 120 and 240 mg/kg 5-ALA, the human equivalent dose of photodynamic diagnosis, revealed no significant increase in toxicity to normal skin or brain tissue compared to ionizing radiation alone. Thus, RDT is expected to enhance RT treatment of glioblastoma without severe toxicity under clinically feasible conditions.

Changes in lactic acid bacteria and components of Awa-bancha by anaerobic fermentation.

Awa-bancha is a post-fermented tea produced in Naka and Kamikatsu, Tokushima, Japan. We investigated the lactic acid bacteria in each stage of production of Awa-bancha and evaluated the relationships with the components. Lactic acid bacteria were isolated from tea leaves cultured with de Man, Rogosa, and Sharpe (MRS) agar plates, and the species were identified by homology of the 16 S rRNA gene and multiplex polymerase chain reaction (PCR) of the recA gene to distinguish the Lactobacillus plantarum group. As a result, a variety of species were isolated from the raw tea leaves, and Lactobacillus pentosus was isolated most frequently after anaerobic fermentation. Regarding the tea leaf components, organic acids, such as lactic acid, increased, free amino acids decreased, and catechins changed owing to anaerobic fermentation. Our results suggest that the microbial flora mainly composed of L. pentosus is important in the anaerobic fermentation process for flavor formation of Awa-bancha.

DNA Strand Break Properties of Protoporphyrin IX by X-Ray Irradiation against Melanoma.

Recent reports have suggested that 5-aminolevulinic acid (5-ALA), which is a precursor to protoporphyrin IX (PpIX), leads to selective accumulation of PpIX in tumor cells and acts as a radiation sensitizer in vitro and in vivo in mouse models of melanoma, glioma, and colon cancer. In this study, we investigated the effect of PpIX under X-ray irradiation through ROS generation and DNA damage. ROS generation by the interaction between PpIX and X-ray was evaluated by two kinds of probes, 3'-(p-aminophenyl) fluorescein (APF) for hydroxyl radical (•OH) detection and dihydroethidium (DHE) for superoxide (O2•-). •OH showed an increase, regardless of the dissolved oxygen. Meanwhile, the increase in O2•- was proportional to the dissolved oxygen. Strand breaks (SBs) of DNA molecule were evaluated by gel electrophoresis, and the enhancement of SBs was observed by PpIX treatment. We also studied the effect of PpIX for DNA damage in cells by X-ray irradiation using a B16 melanoma culture. X-ray irradiation induced γH2AX, DNA double-strand breaks (DSBs) in the context of chromatin, and affected cell survival. Since PpIX can enhance ROS generation even in a hypoxic state and induce DNA damage, combined radiotherapy treatment with 5-ALA is expected to improve therapeutic efficacy for radioresistant tumors.

The Truth of Toxicity Caused by Yttrium Oxide Nanoparticles to Yeast Cells.

Yttrium oxide (Y2O3) nanoparticles have widespread applications; however, toxicity due to these nanoparticles has also been reported. In this study, we evaluated the in vitro toxicity of Y2O3 nanoparticles according to the technical specifications published by the International Standard Organization (ISO/TS 19337:2016). We used Saccharomyces cerevisiae as a model microorganism represented the environment. We carried out catch ball analysis of yttrium oxide and yttrium ion toxicities. The result showed that Y2O3 nanoparticles (20 mg/5 ml) and YCl3 (5 mg/5 ml) treatment caused oxidative stress in yeast cells. Based on transcriptome analysis, fluorescent spectroscopy, and solubility analysis of Y2O3 nanoparticles, we conclude that the toxicity is due to yttrium ions derived from the nanoparticles. The ions induce oxidative stress and cause protein denaturation, which in turn induces proteasome formation to eliminate denatured proteins. Yttrium nanoparticles induce oxidative stress, which has associated with heavy metal ions. Thus, the use of yttrium nanoparticles or yttrium ions must be controlled like heavy metals.

Enhanced Lipid Production and Molecular Dynamics under Salinity Stress in Green Microalga Chlamydomonas reinhardtii (137C).

Microalgal lipids are a source of valuable nutritional ingredients in biotechnological industries, and are precursors to biodiesel production. Here, the effects of salt-induced stresses, including NaCl, KCl, and LiCl stresses, on the production of lipid in green microalga Chlamydomonas reinhardtii (137c) were investigated. NaCl stress dramatically increased saturated fatty acids (SFAs), which accounted for 70.2% of the fatty acid methyl ester (FAMEs) under stress. In contrary, KCl stress led to a slight increase in SFAs (47.05%) with the remaining being polyunsaturated fatty acids (PUFAs) (45.77%). RT-PCR analysis revealed that the genes involved in FA biosynthesis, such as PDH2, ACCase, MAT and KAS2, were up-regulated by NaCl-induced stress. Conversely, the genes responsible for the Kennedy pathway were suppressed. The alteration of FA homeostasis was further assessed by overexpressing MAT, the enzyme responsible for the production of malonyl-ACP, a key building block for FA biosynthesis, in the cyanobacterium Synechococcus elongatus PCC 7942. Intracellular FA composition was affected, with a predominant synthesis of SFAs in transformed cells. Owing to the diversity and relative abundance of SFAs, monounsaturated fatty acid (MUFAs) and PUFAs enable the feasibility of using microorganisms as a source of microalgal lipids or valuable nutritional ingredients; salt-induced stress and expression of MAT are useful in providing precursors for enhanced lipid production.

Verification of 5-Aminolevurinic Radiodynamic Therapy Using a Murine Melanoma Brain Metastasis Model.

Melanoma is a highly aggressive cancer with a propensity for brain metastases. These can be treated by radiotherapy, but the radiation-resistant nature of melanoma makes the prognosis for melanoma patients with brain metastases poor. Previously, we demonstrated that treatment of mice with subcutaneous melanoma with 5-aminolevurinic acid (5-ALA) and X-rays in combination, ("radiodynamic therapy (RDT)"), instead of with 5-ALA and laser beams ("photodynamic therapy"), improved tumor suppression in vivo. Here, using the B16-Luc melanoma brain metastasis model, we demonstrate that 5-ALA RDT effectively treats brain metastasis. We also studied how 5-ALA RDT damages cells in vitro using a B16 melanoma culture. Cell culture preincubated with 5-ALA alone increased intracellular photosensitizer protoporphyrin IX. On X-ray irradiation, the cells enhanced their ∙OH radical generation, which subsequently induced γH2AX, a marker of DNA double-strand breaks in their nuclei, but decreased mitochondrial membrane potential. After two days, the cell cycle was arrested. When 5-ALA RDT was applied to the brain melanoma metastasis model in vivo, suppression of tumor growth was indicated. Therapeutic efficacy in melanoma treatment has recently been improved by molecular targeted drugs and immune checkpoint inhibitors. Treatment with these drugs is now expected to be combined with 5-ALA RDT to further improve therapeutic efficacy.

RNA Quality Control Using External Standard RNA.

In this paper, we propose a new evaluation method using external standard RNA for quality control of the extracted RNA. RNA Integrity Number and UV absorption are generally used as a basis for RNA quality control; however, these methods do not always reflect the quality of mRNA. While standard RNA is supposedly designed on the basis of mRNA, it has the potential to be used to evaluate the quality of the mRNA. In this study, we took into consideration the three essential factors, viz., yield of mRNA, inhibition to DNA polymerase, and degradation of mRNA for determining the RNA quality using standard RNA. It would be possible to know yield of mRNA and inhibition of the enzyme reaction by adding standard RNA before RNA extraction and looking at standard RNA loss. Degradation was evaluated by comparing the differences in the 3' and 5' regions of the RNA. In our study, it was demonstrated that in the crude extract of Saccharomyces cerevisiae , degradation was comparatively higher at the 3' end of RNA than at the 5' end. Hence, the degree of RNA degradation can be evaluated by comparing the ratio of degradation from the 3' and 5' end.

Ascorbic acid prevents zinc oxide nanoparticle-induced intracellular oxidative stress and inflammatory responses.

Exposure to zinc oxide nanoparticles (ZnO NPs) promotes acute pulmonary toxicity through oxidative stress and inflammation. Furthermore, dissolved zinc from ZnO NPs induces the formation of intracellular reactive oxygen species (ROS). We previously reported that supplemental ascorbic acid (AA) inhibits ZnO NP-induced acute pulmonary toxicity in a rat model; however, the mechanism of this action remains unclear. Therefore, we investigated the effects of AA on ZnO NP-induced cytotoxicity in human lung carcinoma A549 cells. AA was found to suppress intracellular production of ROS, and thus reduce the subsequent inflammation of ZnO NPs. However, intracellular Zn2+ concentrations were higher in AA-treated cells than in AA-untreated cells. AA was found to react with Zn2+ but not with the ZnO NPs themselves. These results suggest the possibility that AA-chelated extracellular Zn2+ and the Zn-AA complex was readily taken up into cell. Even if the intracellular Zn2+ level was high, cytotoxicity might be reduced because the Zn-AA complex was stable. Co-treatment of AA to A549 inhibited ROS production and subsequent intracellular inflammatory responses. These results are consistent with those previously reported from an in vivo model. Thus, two possibilities can be considered about the cytotoxicity-reducing the effect of AA: antioxidant efficacy and chelating effect.

Pressure-Dependent Gene Activation in Yeast Cells.

Hydrostatic pressure is one of the physical factors affecting cellular physiology. Hydrostatic pressure of a few tens MPa decreases the growth rate and a few hundred MPa decreases the cellular viability. To find clues to understand how such pressure effects on living cells relating to damages on protein molecules, we employed yeast DNA microarrays and analyzed genome-wide gene-expression levels in yeast cells which have been exposed to different levels of hydrostatic pressure. These include the cells temporarily adapted to a high pressure (from 0.1 to 30 MPa) and to a low pressure (from 30 to 0.1 MPa). These conditions cause yeast cells decreases of growth rate. We also analyzed gene expression profiles from the cells recovering after the sublethal pressure treatment at 180 MPa at 4 °C for 0 min and at 40 MPa at 4 °C for 16 h. These conditions cause yeast cells decreases of cellular viability. The activated genes by the temporary adaptations to both of the high pressure and the low pressure suggest that proteins related to membrane biosynthesis and cell wall biosynthesis can be crucial targets of pressure-induced damages, whereas the activated genes under recovering conditions after exposure to the sublethal high pressure suggest that proteasome activity and proteins localized in endoplasmic reticulum can be the crucial targets or the essential factors to survive.

The induction of lipid peroxidation during the acute oxidative stress response induced by intratracheal instillation of fine crystalline silica particles in rats.

Crystalline silica (SiO2) is an important material for industry but is considered potentially carcinogenic. Inhalation of a crystalline SiO2 aerosol may contribute to serious lung diseases. Crystalline SiO2 particles are commonly used as a positive control in toxicity assays of particulate materials (e.g. nanoparticles). Crystalline SiO2 induces oxidative stress resulting in lipid peroxidation, but the acute oxidative stress response in the lung is not well understood. Lipid peroxidation during the acute stage of oxidative stress after instillation of crystalline SiO2 into rats was examined by bronchoalveolar lavage fluid (BALF) analysis. The levels of 8-iso-prostaglandin F2α and hydroxyoctadecadienoic acid (HODE) in the BALF were measured using liquid chromatography coupled to quadrupole mass spectrometry. The concentration of the antioxidant protein heme oxygenase-1 (HO-1) in the BALF was determined using enzyme-linked immunosorbent assay. Intratracheal instillation of crystalline SiO2 increased the level of HODE and HO-1 in BALF at 24 h after administration. The levels of HODE and HO-1 returned to baseline at 72 h after instillation. Lactate dehydrogenase leakage was observed only after 1 h instillation. These results suggest that the contribution of oxidative stress to the pulmonary toxicity of crystalline SiO2 is minimal in the early acute stage after exposure.

Evaluation of cellular effects of silicon dioxide nanoparticles.

Silica nanoparticles (nSiO2s) are an important type of manufactured nanoparticles. Although there are some reports about the cytotoxicity of nSiO2, the association between physical and chemical properties of nSiO2s and their cellular effects is still unclear. In this study, we examined the correlation between the physiochemical properties and cellular effects of three kinds of amorphous nSiO2s; sub-micro-scale amorphous SiO2, and micro-scale amorphous and crystalline SiO2 particles. The SiO2 particles were dispersed in culture medium and applied to HaCaT human keratinocytes and A549 human lung carcinoma cells. nSiO2s showed stronger protein adsorption than larger SiO2 particles. Moreover, the cellular effects of SiO2 particles were independent of the particle size and crystalline phase. The extent of cell membrane damage and intracellular ROS levels were different among nSiO2s. Upon exposure to nSiO2s, some cells released lactate dehydrogenase (LDH), whereas another nSiO2 did not induce LDH release. nSiO2s caused a slight increase in intracellular ROS levels. These cellular effects were independent of the specific surface area and primary particle size of the nSiO2s. Additionally, association of solubility and protein adsorption ability of nSiO2 to its cellular effects seemed to be small. Taken together, our data suggest that nSiO2s do not exert potent cytotoxic effects on cells in culture, especially compared to the effects of micro-scale SiO2 particles. Further studies are needed to address the role of surface properties of nSiO2s on cellular processes and cytotoxicity.

Cellular effects of manufactured nanoparticles: effect of adsorption ability of nanoparticles.

Nanoparticles are important industrial materials. However, many nanoparticles show biological effects, including toxic activity. Metal ion release is the most important factor affecting the biological effects of nanoparticles. In addition, nanoparticles have large adsorption ability. The adsorption ability, in particular protein adsorption to nanoparticles, has an effect on cellular uptake and cellular metabolisms. Moreover, the adsorption ability of nanoparticles causes artificial effects in in vitro systems. Consequently, accurate determination of released or secreted proteins such as lactate dehydrogenase and cytokines adsorbed to nanoparticles is affected. In addition, artificial effects cause overestimation or underestimation of the cytotoxicity of nanoparticles. Therefore, measurement of the protein adsorption of nanoparticles is important. Some methods for the determination of the adsorption to nanoparticles have been suggested. The flow field-flow fractionation method is one of the efficient techniques for determining proteins on the surface of nanoparticles. The cellular effects caused by nanoparticles should be carefully considered.

Actin-related protein Arp6 influences H2A.Z-dependent and -independent gene expression and links ribosomal protein genes to nuclear pores.

Actin-related proteins are ubiquitous components of chromatin remodelers and are conserved from yeast to man. We have examined the role of the budding yeast actin-related protein Arp6 in gene expression, both as a component of the SWR1 complex (SWR-C) and in its absence. We mapped Arp6 binding sites along four yeast chromosomes using chromatin immunoprecipitation from wild-type and swr1 deleted (swr1Delta) cells. We find that a majority of Arp6 binding sites coincide with binding sites of Swr1, the catalytic subunit of SWR-C, and with the histone H2A variant Htz1 (H2A.Z) deposited by SWR-C. However, Arp6 binding detected at centromeres, the promoters of ribosomal protein (RP) genes, and some telomeres is independent of Swr1 and Htz1 deposition. Given that RP genes and telomeres both show association with the nuclear periphery, we monitored the ability of Arp6 to mediate the localization of chromatin to nuclear pores. Arp6 binding is sufficient to shift a randomly positioned locus to nuclear periphery, even in a swr1Delta strain. Arp6 is also necessary for the pore association of its targeted RP promoters possibly through cell cycle-dependent factors. Loss of Arp6, but not Htz1, leads to an up-regulation of these RP genes. In contrast, the pore-association of GAL1 correlates with Htz1 deposition, and loss of Arp6 reduces both GAL1 activation and peripheral localization. We conclude that Arp6 functions both together with the nucleosome remodeler Swr1 and also without it, to mediate Htz1-dependent and Htz1-independent binding of chromatin domains to nuclear pores. This association is shown to have modulating effects on gene expression.

Chromium(III) oxide nanoparticles induced remarkable oxidative stress and apoptosis on culture cells.

Chromium(III) oxide (Cr(2)O(3)) is used for industrial applications such as catalysts and pigments. In the classical form, namely the fine particle, Cr(2)O(3) is insoluble and chemically stable. It is classified as a low-toxicity chromium compound. Recently, industrial application of nanoparticles (a new form composed of small particles with a diameter of ≤100 nm, in at least one dimension) has been increasing. Cellular effects induced by Cr(2)O(3) nanoparticles are not known. To shed light upon this, the release of soluble chromium from Cr(2)O(3) nano- and fine-particles in culture medium was compared. Fine Cr(2)O(3) particles were insoluble in the culture medium; on the contrary, Cr(2)O(3) nanoparticles released soluble hexavalent chromium into the culture medium. Cr(2)O(3) nanoparticles showed severe cytotoxicity. The effect of Cr(2)O(3) nanoparticles on cell viability was higher than that of fine particles. Cr(2)O(3) nanoparticles showed cytotoxicity equal to that of hexavalent chromium (K(2)Cr(2)O(7)). Human lung carcinoma A549 cells and human keratinocyte HaCaT cells showed an increase in intracellular reactive oxygen species (ROS) level and activation of antioxidant defense systems on exposure to Cr(2)O(3) nanoparticles. Exposure of Cr(2)O(3) nanoparticles led to caspase-3 activation, showing that the decrease in cell viability by exposure to Cr(2)O(3) nanoparticles was caused by apoptosis. Cellular responses were stronger in the Cr(2)O(3) nanoparticles-exposed cells than in fine Cr(2)O(3) - and CrCl(3) -exposed cells. Cellular uptake of Cr(2)O(3) particles were observed in nano- and fine-particles. The cellular influence of the extracellular soluble trivalent chromium was lower than that of Cr(2)O(3) nanoparticles. Cr(2)O(3) nanoparticles showed cytotoxicity by hexavalent chromium released at outside and inside of cells. The cellular influences of Cr(2)O(3) nanoparticles matched those of hexavalent chromium. In conclusion, Cr(2)O(3) nanoparticles have a high cytotoxic potential.

In vitro evaluation of cellular response induced by manufactured nanoparticles.

"Nanoparticle" is defined as the particles whose diameter in at least one dimension is less than 100 nm. Compared with fine-particles, nanoparticles have large specific surface area. There is a dramatic increase over fine-particles in chemical and physical activities, such as ion release, adsorption ability, and ROS production. These properties are important for industrial use, and many nanoparticles are already used in products familiar to consumers as sunscreens and cosmetics. However, nanoparticle properties beneficial to the industry may also induce biological influences, including toxic activities. Recently, many investigations about the toxicology of nanoparticles have been reported. In the evaluation of nanoparticles toxicity, in vitro studies give us important information, especially in terms of toxic mechanisms. In vitro studies showed that some nanoparticles induce oxidative stress, apoptosis, production of cytokines, and cell death. There are reports that cellular influences of other nanoparticles are small. There are also reports of different results, some with low and some with high influences, for the same nanoparticle. One of the causes of this inconsistency might be a diremption of the living body influence study and the characterization study. Characterization of individual nanoparticles and their dispersions are essential for in vitro evaluation of their biological effects since each nanoparticle shows unique chemical and physical properties. Particularly, the aggregation state and metal ion release ability of nanoparticles affect its cellular influences. Reports concerning the characterization in the in vitro toxicity assessment are increasing. For an accurate risk assessment of nanoparticles, in this review, we outline recent studies of in vitro evaluation of cellular influences induced by nanoparticles. Moreover, we also introduce current studies about the characterization methods of nanoparticles and their dispersions for toxicological evaluation.

Comparison of acute oxidative stress on rat lung induced by nano and fine-scale, soluble and insoluble metal oxide particles: NiO and TiO2.

The aim of the present study is to understand the association between metal ion release from nickel oxide (NiO) nanoparticles and induction of oxidative stress in the lung. NiO nanoparticles have cytotoxic activity through nickel ion release and subsequent oxidative stress. However, the interaction of oxidative stress and nickel ion release in vivo is still unclear. In the present study, we examined the effect of metal ion release on oxidative stress induced by NiO nanoparticles. Additionally, nano and fine TiO(2) particles as insoluble particles were also examined. Rat lung was exposed to NiO and TiO(2) nanoparticles by intratracheal instillation. The NiO nanoparticles released Ni(2+) in dispersion. Bronchoalveolar lavage fluid (BALF) was collected at 1, 24, 72 h and 1 week after instillation. The lactate dehydrogenase (LDH) and HO-1 levels were elevated at 24 and 72 h after instillation in the animals exposed to the NiO nanoparticles. On the other hand, total hydroxyoctadecadienoic acid (tHODE), which is an oxidative product of linoleic acid, as well as SP-D and α-tochopherol levels were increased at 72 h and 1 week after instillation. Fine NiO particles, and nano and fine TiO(2) particles did not show lung injury or oxidative stress from 1 h to 1 week after instillation. These results suggest that Ni(2+) release is involved in the induction of oxidative stress by NiO nanoparticles in the lung. Ni(2+) release from NiO nanoparticles is an important factor inoxidative stress-related toxicity, not only in vitro but also in vivo.

[Significance of comprehensive gene expression analysis for evaluation of biological effects of manufactured nanomaterials].

The industrial applications of manufactured nanomaterials (MNs) are expected to be extended to next-generation devices. On the other hand, concern over the effects of MNs on human health has risen owing to advances in the development of nanotechnology. Indeed, little is known about the mechanism of action of MNs. The New Energy and Industrial Technology Development Organization of Japan (NEDO) launched a new research project entitled "Evaluating risks associated with manufactured nanomaterials (P10024)" in 2006. The project demonstrated no adverse effects of MN inhalation exposure on the rat lungs, as determined by histopathological examination and bronchoalveolar lavage (BAL) fluid analysis. In parallel with this research, we have performed comparative gene expression analysis using DNA microarrays in rat lungs after inhalation exposure (4 weeks, 6 hours a day, 5 days a week) to single-wall nanotubes (SWCNTs), multiwall nanotubes (MWCNTs), C60 fullerene and ultrafine nickel oxide particles (Uf-NiO) as reference materials for the purpose of gaining insights into the molecular events following the exposure. In this review, we introduce an outline of the project, and discuss about the significance of comparative gene expression analysis for evaluation of the biological effects of MNs.