Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 18 de 18
Filter
1.
Sci Rep ; 13(1): 11779, 2023 07 21.
Article in English | MEDLINE | ID: mdl-37479866

ABSTRACT

Sugi (Cryptomeria japonica D. Don) is an economically important coniferous tree in Japan. However, abundant sugi pollen grains are dispersed and transported by the wind each spring and cause a severe pollen allergy syndrome (Japanese cedar pollinosis). The use of pollen-free sugi that cannot produce pollen has been thought as a countermeasure to Japanese cedar pollinosis. The sugi CjACOS5 gene is an ortholog of Arabidopsis ACOS5 and rice OsACOS12, which encode an acyl-CoA synthetase that is involved in the synthesis of sporopollenin in pollen walls. To generate pollen-free sugi, we mutated CjACOS5 using the CRISPR/Cas9 system. As a result of sugi transformation mediated by Agrobacterium tumefaciens harboring the CjACOS5-targeted CRISPR/Cas9 vector, 1 bp-deleted homo biallelic mutant lines were obtained. Chimeric mutant lines harboring both mutant and wild-type CjACOS5 genes were also generated. The homo biallelic mutant lines had no-pollen in male strobili, whereas chimeric mutant lines had male strobili with or without pollen grains. Our results suggest that CjACOS5 is essential for the production of pollen in sugi and that its disruption is useful for the generation of pollen-free sugi. In addition to conventional transgenic technology, genome editing technology, including CRISPR/Cas9, can confer new traits on sugi.


Subject(s)
Arabidopsis , Cryptomeria , Rhinitis, Allergic, Seasonal , Humans , Rhinitis, Allergic, Seasonal/genetics , Trees , Cryptomeria/genetics , CRISPR-Cas Systems , Pollen/genetics
2.
Cancer Sci ; 114(1): 152-163, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36102493

ABSTRACT

Recent comprehensive analyses of mtDNA and orthogonal RNA-sequencing data revealed that in numerous human cancers, mtDNA copy numbers and mtRNA amounts are significantly reduced, followed by low respiratory gene expression. Under such conditions (called mt-Low), cells encounter severe cell proliferation defects; therefore, they must acquire countermeasures against this fatal disadvantage during malignant transformation. This study elucidated a countermeasure against the mt-Low condition-induced antiproliferative effects in hepatocellular carcinoma (HCC) cells. The mechanism relied on the architectural transcriptional regulator HMGA2, which was preferably expressed in HCC cells of the mt-Low type in vitro and in vivo. Detailed in vitro analyses suggest that HMGA2 regulates insulin-like growth factor binding protein 1 (IGFBP1) expression, leading to AKT activation, which then phosphorylates the cyclin-dependent kinase inhibitor (CKI), P27KIP1, and facilitates its ubiquitin-mediated degradation. Accordingly, intervention in the HMGA2 function by RNAi resulted in an increase in P27KIP1 levels and an induction of senescence-like cell proliferation inhibition in mt-Low-type HCC cells. Conclusively, the HMGA2/IGFBP1/AKT axis has emerged as a countermeasure against P27KIP1 CKI upregulation under mt-Low conditions, thereby circumventing cell proliferation inhibition and supporting the tumorigenic state. Notably, similar to in vitro cell lines, HMGA2 was likely to regulate IGFBP1 expression in HCC in vivo, thereby contributing to poor patient prognosis. Considering the significant number of cases under mt-Low or the threat of CKI upregulation cancer-wide, the axis is noteworthy as a vulnerability of cancer cells or target for tumor-agnostic therapy inducing irreversible cell proliferation inhibition via CKI upregulation in a large population with cancer.


Subject(s)
Carcinoma, Hepatocellular , Liver Neoplasms , Humans , Carcinoma, Hepatocellular/pathology , Cyclin-Dependent Kinase Inhibitor p27/genetics , Cyclin-Dependent Kinase Inhibitor p27/metabolism , RNA , Proto-Oncogene Proteins c-akt/metabolism , Liver Neoplasms/pathology , DNA, Mitochondrial , Insulin-Like Growth Factor Binding Protein 1 , Cell Proliferation/genetics , Protein Kinase Inhibitors/pharmacology , Cell Line, Tumor , Gene Expression Regulation, Neoplastic
3.
Front Plant Sci ; 13: 825340, 2022.
Article in English | MEDLINE | ID: mdl-35211140

ABSTRACT

Sugi (Japanese cedar, Cryptomeria japonica) is the most important forestry tree species in Japan, covering 44% of the total artificial forest area. Large amounts of pollen released from these forests each spring cause allergic reactions in approximately 40% of the population, which are a serious social and public health problem in Japan. As a countermeasure, there is an urgent need to reforest using male-sterile plants (MSPs; pollen-free plants); however, the production of MSPs via conventional methods is inefficient, time consuming, and requires considerable resources in terms of labor and space. In the present paper, we described an improved and simplified methodology for the efficient propagation of pollen-free Japanese cedar, combining the use of genetic markers (marker-assisted selection or marker-aided selection) for the early selection of male-sterile genotypes and the use of somatic embryogenesis (SE) for the clonal mass propagation of seedlings. We describe all the stages involved in the production process of somatic seedlings. Our results demonstrated that this methodology easily and efficiently produces MSPs with a discrimination rate of 100% in a short period of time. Production of 243.6 ± 163.6 cotyledonary embryos per plate, somatic embryo germination, and plantlet conversion frequencies of 87.1 ± 11.9% and 84.8 ± 12.6%, respectively, and a 77.6 ± 12.1% survival rate after ex vitro acclimatization was achieved. Moreover, we also describe an easy method for the collection of somatic embryos prior to germination, as well as an efficient and practical method for their storage at 5°C. Finally, a representative schedule for the propagation of pollen-free sugi somatic seedlings is presented as a reference for practical uses. This methodology will definitively help to accelerate the production of C. japonica MSPs across Japan.

4.
Front Plant Sci ; 12: 748110, 2021.
Article in English | MEDLINE | ID: mdl-34712261

ABSTRACT

Pollen allergy caused by sugi (Japanese cedar, Cryptomeria japonica) is a serious problem in Japan. One of the measures against pollinosis is the use of male-sterile plants (MSPs; pollen-free plants). In this context, the development of a novel technique for the efficient production of sugi MSPs, which combines marker-assisted selection (MAS) with somatic embryogenesis (SE), was recently reported by our research group. To improve the efficiency of MSP production, in this paper we report improved MAS for male-sterile individuals from embryogenic cells, cotyledonary embryos, and somatic plants of sugi using a newly developed marker in the form of the causative mutation of MS1 itself, selecting individuals with ms1-1 and ms1-2 male-sterile mutations. We also describe simplified methods for extracting DNA from different plant materials and for MAS using LAMP diagnostics. Finally, we show that MAS can be efficiently performed using the one-step indel genotyping (ING) marker developed in this study and using InstaGene for DNA extraction. The combination of SE and 100% accurate marker selection during the embryogenic cell stage enables the mass production of MS1 male-sterile sugi seedlings.

5.
Plants (Basel) ; 10(5)2021 Apr 26.
Article in English | MEDLINE | ID: mdl-33926083

ABSTRACT

This paper presents the results of several experiments identifying basal salts (BS) contained in maturation medium, polyethylene glycol (PEG) concentration, abscisic acid (ABA) concentration, additional supplementation with potassium chloride (KCl), amino acid (AA) concentration, and proliferation culture medium (PCM) as the main culture factors affecting somatic embryo maturation in sugi (Japanese cedar, Cryptomeria japonica, Cupressaceae). Highly efficient embryo maturation was achieved when embryogenic cell lines (ECLs) were cultured on media supplemented with a combination of PEG, ABA, and AAs. More than 1000 embryos per gram of fresh weight (FW) can be produced on EM maturation medium supplemented with 175 g L-1 PEG, 100 µM ABA, 2 g L-1 glutamine, 1 g L-1 asparagine, and 0.5 g L-1 arginine.

6.
Plants (Basel) ; 10(2)2021 Feb 19.
Article in English | MEDLINE | ID: mdl-33669646

ABSTRACT

This study aimed to obtain information from several embryogenic cell (EC) genotypes analyzing the factors that affect somatic embryogenesis (SE) initiation in sugi (Cryptomeria japonica, Cupressaceae) to apply them in the improvement of protocols for efficient induction of embryogenic cell lines (ECLs). The results of several years of experiments including studies on the influence of initial explant, seed collection time, and explant genotype as the main factors affecting SE initiation from male-fertile, male-sterile, and polycross-pollinated-derived seeds are described. Initiation frequencies depending on the plant genotype varied from 1.35 to 57.06%. The best induction efficiency was achieved when seeds were collected on mid-July using the entire megagametophyte as initial explants. The extrusion of ECs started approximately after 2 weeks of culture, and the establishment of ECLs was observed mostly 4 weeks after extrusion on media with or without plant growth regulators (PGRs). Subsequently, induced ECLs were maintained and proliferated on media with PGRs by 2-3-week-interval subculture routines. Although, the initial explant, collection time, and culture condition played important roles in ECL induction, the genotype of the plant material of sugi was the most influential factor in SE initiation.

7.
PLoS One ; 15(12): e0244634, 2020.
Article in English | MEDLINE | ID: mdl-33373415

ABSTRACT

Somatic embryogenesis (SE), which is in vitro regeneration of plant bodies from somatic cells, represents a useful means of clonal propagation and genetic engineering of forest trees. While protocols to obtain calluses and induce regeneration in somatic embryos have been reported for many tree species, the knowledge of molecular mechanisms of SE development is still insufficient to achieve an efficient supply of somatic embryos required for the industrial application. Cryptomeria japonica, a conifer species widely used for plantation forestry in Japan, is one of the tree species waiting for a secure SE protocol; the probability of normal embryo development appears to depend on genotype. To discriminate the embryogenic potential of embryonal masses (EMs) and efficiently obtain normal somatic embryos of C. japonica, we investigated the effects of genotype and transcriptome on the variation in embryogenic potential. Using an induction experiment with 12 EMs each from six genotypes, we showed that embryogenic potential differs between/within genotypes. Comparisons of gene expression profiles among EMs with different embryogenic potentials revealed that 742 differently expressed genes were mainly associated with pattern forming and metabolism. Thus, we suggest that not only genotype but also gene expression profiles can determine success in SE development. Consistent with previous findings for other conifer species, genes encoding leafy cotyledon, wuschel, germin-like proteins, and glutathione-S-transferases are likely to be involved in SE development in C. japonica and indeed highly expressed in EMs with high-embryogenic potential; therefore, these proteins represent candidate markers for distinguishing embryogenic potential.


Subject(s)
Cryptomeria/growth & development , Gene Expression Profiling/methods , Gene Regulatory Networks , Plant Somatic Embryogenesis Techniques/methods , Cryptomeria/genetics , Gene Expression Regulation, Developmental , Gene Expression Regulation, Plant , Genetic Variation , Genotype , Japan , Plant Proteins , Sequence Analysis, RNA
8.
Plants (Basel) ; 9(8)2020 Aug 13.
Article in English | MEDLINE | ID: mdl-32823795

ABSTRACT

One of the possible countermeasures for pollinosis caused by sugi (Cryptomeria japonica), a serious public health problem in Japan, is the use of male sterile plants (MSPs; pollen-free plants). However, the production efficiencies of MSPs raised by conventional methods are extremely poor, time consuming, and resulting in a high seedling cost. Here, we report the development of a novel technique for efficient production of MSPs, which combines marker-assisted selection (MAS) and somatic embryogenesis (SE). SE from four full sib seed families of sugi, carrying the male sterility gene MS1, was initiated using megagametophyte explants that originated from four seed collections taken at one-week intervals during the month of July 2017. Embryogenic cell lines (ECLs) were achieved in all families, with initiation rates varying from 0.6% to 59%. Somatic embryos were produced from genetic marker-selected male sterile ECLs on medium containing maltose, abscisic acid (ABA), polyethylene glycol (PEG), and activated charcoal (AC). Subsequently, high frequencies of germination and plant conversion (≥76%) were obtained on plant growth regulator-free medium. Regenerated plantlets were acclimatized successfully, and the initial growth of male sterile somatic plants was monitored in the field.

9.
Exp Cell Res ; 389(1): 111889, 2020 04 01.
Article in English | MEDLINE | ID: mdl-32032602

ABSTRACT

The copy number of mitochondrial DNA (mtDNA) is decreased in most cancer types, including hepatocellular carcinoma (HCC), compared to normal counterparts. However, a decrease in mtDNA usually leads to defects in cell proliferation, which contradicts the robustness of cancer cell proliferation. In this study, we found that four out of seven HCC cell lines were of the mtDNA-less type. Interestingly, FOXM1, a member of the FOX transcription factor family, was highly expressed in a subset of them with proliferative potential maintained. B-MYB, a partner of FOXM1, was also expressed in the same cell lines. RNAi-mediated experiments demonstrated that when FOXM1/B-MYB was silenced in the cell lines, cell cycle-related genes were downregulated, while p21Cip1 was induced with senescence-associated ß-galactosidase, resulting in G1/S cell cycle arrest. These results suggest that high expression of FOXM1/B-MYB is critical for sustaining cell proliferation in mtDNA-less cells. In addition, we found that high expression of FOXM1 was mediated by the deubiquitinating enzyme, OTUB1, in one cell line. Thus, interference with FOXM1/B-MYB expression, such as through OTUB1 inhibition, may induce a dormant state of senescence-like proliferation arrest in mtDNA-less cancer cells. This finding may be utilized for the development of precision medicine for relevant cancers.


Subject(s)
Carcinoma, Hepatocellular/genetics , Cell Proliferation/genetics , DNA, Mitochondrial/genetics , Forkhead Box Protein M1/genetics , Liver Neoplasms/genetics , Carcinoma, Hepatocellular/pathology , Cell Line, Tumor , Cells, Cultured , DNA Copy Number Variations , Gene Expression Regulation, Neoplastic , Hepatocytes/metabolism , Hepatocytes/pathology , Humans , Liver Neoplasms/pathology , Up-Regulation/genetics
10.
Physiol Rep ; 7(9): e14062, 2019 05.
Article in English | MEDLINE | ID: mdl-31087530

ABSTRACT

Physical exercise has demonstrated benefits for managing nonalcoholic fatty liver disease (NAFLD). However, in daily life maintaining exercise without help may be difficult. A whole-body vibration device (WBV) has been recently introduced as an exercise modality that may be suitable for patients who have difficulty engaging in exercise. We tested WBV in patients with NAFLD and estimated its effectiveness. We studied the effects of a 6-month WBV program on hepatic steatosis and its underlying pathophysiology in 25 patients with NAFLD. Seventeen patients with NAFLD were designated as a control group. After WBV exercise, body weight in the study group decreased by only 2.5% compared with the control group. However, we found significant increases in muscle area (+2.6%) and strength (+20.5%) and decreases in fat mass (-6.8%). The hepatic (-9.9%) and visceral (-6.2%) fat content also significantly decreased (P < 0.05). There was substantial lowering of hepatic stiffness (-15.7%), along with improvements in the levels of inflammatory markers; tumor necrosis factor alpha (-50.9%), adiponectin (+12.0%), ferritin (-33.2%), and high-sensitivity C-reactive protein (-43.0%) (P < 0.05). These results suggest that WBV is an exercise option for patients with NAFLD that is effective, efficient, and convenient.


Subject(s)
Non-alcoholic Fatty Liver Disease/therapy , Vibration/therapeutic use , Adipokines/blood , Adipose Tissue/pathology , Adult , Anthropometry/methods , Apoptosis/physiology , Body Composition/physiology , Body Weight/physiology , Elasticity , Elasticity Imaging Techniques/methods , Exercise Therapy/methods , Female , Humans , Lipid Metabolism/physiology , Liver/diagnostic imaging , Liver/physiopathology , Magnetic Resonance Spectroscopy , Male , Middle Aged , Muscle Strength/physiology , Muscle, Skeletal/pathology , Non-alcoholic Fatty Liver Disease/diagnostic imaging , Non-alcoholic Fatty Liver Disease/pathology , Non-alcoholic Fatty Liver Disease/physiopathology , Oxidative Stress/physiology , Prospective Studies
11.
Front Plant Sci ; 10: 31, 2019.
Article in English | MEDLINE | ID: mdl-30745904

ABSTRACT

Somatic embryogenesis (SE) in not only one of the most promising techniques for mass propagation of selected trees, but also is a valuable tool for basic research studies in cell biology and genetic engineering, and it allows the long-term ex situ conservation of genetic resources by cryopreservation techniques. This review reports the most recent progress in SE, protoplast culture, and cryopreservation of four important Japanese pines (Pinus thunbergii, Pinus densiflora, Pinus armandii var. amamiana, and Pinus luchuensis). Induction of embryogenic tissues (ET), embryogenic culture maintenance/proliferation, production of somatic embryos, germination, and conversion to plants are described focusing on the protocols most commonly reported for plant production in Pinus species through to SE.

12.
J Plant Res ; 131(5): 789-802, 2018 Sep.
Article in English | MEDLINE | ID: mdl-29948486

ABSTRACT

Glutamine synthetase (GS) localized in the chloroplasts, GS2, is a key enzyme in the assimilation of ammonia (NH3) produced from the photorespiration pathway in angiosperms, but it is absent from some coniferous species belonging to Pinaceae such as Pinus. We examined whether the absence of GS2 is common in conifers (Pinidae) and also addressed the question of whether assimilation efficiency of photorespiratory NH3 differs between conifers that may potentially lack GS2 and angiosperms. Search of the expressed sequence tag database of Cryptomeria japonica, a conifer in Cupressaceae, and immunoblotting analyses of leaf GS proteins of 13 species from all family members in Pinidae revealed that all tested conifers exhibited only GS1 isoforms. We compared leaf NH3 compensation point (γNH3) and the increments in leaf ammonium content per unit photorespiratory activity (NH3 leakiness), i.e. inverse measures of the assimilation efficiency, between conifers (C. japonica and Pinus densiflora) and angiosperms (Phaseolus vulgaris and two Populus species). Both γNH3 and NH3 leakiness were higher in the two conifers than in the three angiosperms tested. Thus, we concluded that the absence of GS2 is common in conifers, and assimilation efficiency of photorespiratory NH3 is intrinsically lower in conifer leaves than in angiosperm leaves. These results imply that acquisition of GS2 in land plants is an adaptive mechanism for efficient NH3 assimilation under photorespiratory environments.


Subject(s)
Ammonia/metabolism , Ammonium Compounds/metabolism , Glutamate-Ammonia Ligase/metabolism , Magnoliopsida/physiology , Tracheophyta/physiology , Chloroplasts/metabolism , Environment , Glutamate-Ammonia Ligase/genetics , Light , Magnoliopsida/radiation effects , Oxygen/metabolism , Plant Proteins/genetics , Plant Proteins/metabolism , Tracheophyta/radiation effects
13.
Ther Clin Risk Manag ; 11: 371-80, 2015.
Article in English | MEDLINE | ID: mdl-25767392

ABSTRACT

BACKGROUND: Exercise training is an effective therapy for nonalcoholic fatty liver disease (NAFLD). Hybrid training (HYB) of voluntary and electrical muscle contractions was developed to prevent disuse atrophy during space flight. HYB can be applied to obtain a strength training effect accompanying articular movement. In this pilot study, we aimed to investigate the therapeutic efficacy of HYB in NAFLD. METHODS: A total of 15 middle-aged obese women with NAFLD who had no improvement in serum alanine aminotransferase levels and/or liver fat deposition after 12 weeks of lifestyle counseling participated in an HYB program. HYB of the quadriceps and hamstrings was conducted for 20 minutes twice a week for 24 weeks. RESULTS: NAFLD patients showed attenuated intramyocellular lipid levels in the quadriceps after the HYB intervention (-15.5%). Levels of leptin (-17.4%), tumor necrosis factor-α (-23.2%), and interleukin-6 (-30.5%) were also decreased after the intervention. HYB led to a significant body weight reduction (-4.7%), which in turn was associated with a significant decrease in serum alanine aminotransferase (-35.8%), gamma-glutamyl transpeptidase (-21.6%), ferritin (-16.0%), oxidative stress (-17.8%) levels, and insulin resistance values (-2.7%). CONCLUSION: In NAFLD, HYB exerts an antiobesity effect and attenuates liver dysfunction and insulin resistance in association with an increase in muscle strength and a decrease in ectopic muscle fat. Therefore, HYB has great potential as a new type of exercise therapy for liver disease in patients with NAFLD.

14.
Mycorrhiza ; 25(3): 237-41, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25236465

ABSTRACT

Tricholoma matsutake is an ectomycorrhizal basidiomycete that associates with Pinaceae in the Northern Hemisphere and produces prized "matsutake" mushrooms. We questioned whether the symbiont could associate with a birch that is an early-successional species in boreal, cool-temperate, or subalpine forests. In the present study, we demonstrated that T. matsutake can form typical ectomycorrhizas with Betula platyphylla var. japonica; the associations included a Hartig net and a thin but distinct fungal sheath, as well as the rhizospheric mycelial aggregate "shiro" that is required for fruiting in nature. The in vitro shiro also emitted a characteristic aroma. This is the first report of an ectomycorrhizal formation between T. matsutake and a deciduous broad-leaved tree in the boreal or cool-temperate zones that T. matsutake naturally inhabits.


Subject(s)
Betula/microbiology , Mycorrhizae/physiology , Pinaceae/microbiology , Tricholoma/physiology , Betula/growth & development , Cold Temperature , Forests , Mycorrhizae/growth & development , Pinaceae/growth & development , Symbiosis , Trees/growth & development , Trees/microbiology , Tricholoma/growth & development
15.
Ther Clin Risk Manag ; 10: 925-36, 2014.
Article in English | MEDLINE | ID: mdl-25404857

ABSTRACT

BACKGROUND: While aerobic training is generally recommended as therapeutic exercise in guidelines, the effectiveness of resistance training has recently been reported in the management of nonalcoholic fatty liver disease (NAFLD). Acceleration training (AT) is a new training method that provides a physical stimulation effect on skeletal muscles by increasing gravitational acceleration with vibration. AT has recently been indicated as a component of medicine. In this study, we evaluated the effectiveness of AT in the management of NAFLD in obese subjects. METHODS: A total of 18 obese patients with NAFLD who had no improvement in liver function test abnormalities and/or steatosis grade after 12 weeks of lifestyle counseling were enrolled in an AT program. These patients attended a 20-minute session of AT twice a week for 12 consecutive weeks. RESULTS: During the AT program, the NAFLD patients showed a modest increase in the strength (+12.6%) and cross-sectional area (+3.1%) of the quadriceps, coupled with a significant reduction in intramyocellular lipids (-26.4%). Notably, they showed a modest reduction in body weight (-1.9%), abdominal visceral fat area (-3.4%), and hepatic fat content (-8.7%), coupled with a significant reduction in levels of aminotransferase (-15.7%), γ-glutamyltransferase (-14.4%), leptin (-9.7%), interleukin-6 (-26.8%), and tumor necrosis factor-α (-17.9%), and a significant increase of adiponectin (+8.7%). On a health-related quality of life survey, the patients showed an improvement in physical functioning (+17.3%), physical role (+9.7%), general health (+22.1), and social functioning (+6.0%). CONCLUSION: AT reduced hepatic and intramyocellular fat contents and ameliorated liver function test abnormalities in obese patients with NAFLD, which was coupled with improved physical function and body adiposity. AT is clinically beneficial for the management of NAFLD.

16.
Mycorrhiza ; 24(4): 315-21, 2014 May.
Article in English | MEDLINE | ID: mdl-24158697

ABSTRACT

We previously reported that Tricholoma matsutake and Tricholoma fulvocastaneum, ectomycorrhizal basidiomycetes that associate with Pinaceae and Fagaceae, respectively, in the Northern Hemisphere, could interact in vitro as a root endophyte of somatic plants of Cedrela odorata (Meliaceae), which naturally harbors arbuscular mycorrhizal fungi in South America, to form a characteristic rhizospheric colony or "shiro". We questioned whether this phenomenon could have occurred because of plant-microbe interactions between geographically separated species that never encounter one another in nature. In the present study, we document that these fungi formed root endophyte interactions and shiro within 140 days of inoculation with somatic plants of Prunus speciosa (=Cerasus speciosa, Rosaceae), a wild cherry tree that naturally harbors arbuscular mycorrhizal fungi in Japan. Compared with C. odorata, infected P. speciosa plants had less mycelial sheath surrounding the exodermis, and the older the roots, especially main roots, the more hyphae penetrated. In addition, a large number of juvenile roots were not associated with hyphae. We concluded that such root endophyte interactions were not events isolated to the interactions between exotic plants and microbes but could occur generally in vitro. Our pure culture system with a somatic plant allowed these fungi to express symbiosis-related phenotypes that varied with the plant host; these traits are innately programmed but suppressed in nature and could be useful in genetic analyses of plant-fungal symbiosis.


Subject(s)
Endophytes/physiology , Plant Roots/microbiology , Prunus/microbiology , Symbiosis , Tricholoma/physiology
17.
Mycorrhiza ; 23(3): 235-42, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23064771

ABSTRACT

The ectomycorrhizal basidiomycete Tricholoma matsutake associates with members of the Pinaceae such as Pinus densiflora (red pine), forming a rhizospheric colony or "shiro," which produces the prized "matsutake" mushroom. We investigated whether the host specificity of T. matsutake to conifers is innately determined using somatic plants of Cedrela odorata, a tropical broad-leaved tree (Meliaceae) that naturally harbors arbuscular mycorrhizal fungi. We found that T. matsutake could form in vitro shiro with C. odorata 140 days after inoculation, as with P. densiflora. The shiro was typically aromatic like that of P. densiflora. However, this was a root endophytic interaction unlike the mycorrhizal association with P. densiflora. Infected plants had epidermal tissues and thick exodermal tissues outside the inner cortex. The mycelial sheath surrounded the outside of the epidermis, and the hyphae penetrated into intra- and intercellular spaces, often forming hyphal bundles or a pseudoparenchymatous organization. However, the hyphae grew only in the direction of vascular bundles and did not form Hartig nets. Tricholoma fulvocastaneum or "false matsutake" naturally associates with Fagaceae and was also able to associate with C. odorata as a root endophyte. With T. matsutake, C. odorata generated a number of roots and showed greatly enhanced vigor, while with T. fulvocastaneum, it generated a smaller number of roots and showed somewhat lesser vigor. We argue that the host-plant specificity of ectomycorrhizal matsutake is not innately determined, and that somatic arbuscular mycorrhizal plants have a great potential to form mutualistic relationships with ectomycorrhizal fungi.


Subject(s)
Agaricales/physiology , Basidiomycota/metabolism , Cedrela/microbiology , Mycorrhizae/physiology , Plant Roots/microbiology , Species Specificity , Symbiosis
18.
Brain Dev ; 28(3): 162-9, 2006 Apr.
Article in English | MEDLINE | ID: mdl-16466882

ABSTRACT

The continuous performance test (CPT) is designed to measure sustained attention quantitatively. Several CPTs are used clinically. We have made changes to the conventional type of visual CPT, by displaying auditory and visual noise along with target or non-target stimuli. By influencing the recognition of the subjects in this way, the changes were intended to increase the sensitivity of detection of inattention and impulsiveness, to make CPT more useful for diagnosis, and to examine the effect of noise on AD/HD children during CPT performance. Its usefulness for AD/HD diagnosis and the reaction of AD/HD children to noise were examined using newly developed computer software. Using this CPT analysis, a significant difference was observed in all measurements, except mean reaction time, between the control and AD/HD groups, showing that it was useful as a supplementary diagnostic method for AD/HD, and was more useful in the younger age group than in the older age group, as the same for conventional CPTs. As compared to no-noise sessions, commission and omission errors both increased significantly in auditory and visual noise sessions. Thus, analyzing the changes in measurements during noise sessions will improve the diagnosis of inattention and combined AD/HD subtypes. Furthermore, it was suggested that analysis of the effects of noise on AD/HD children will benefit their handling in an educational environment. Since omission errors were decreased in AD/HD children by noise during the CPT performance as compared to the control group, noise may induce attention in AD/HD children. The present study presents new findings on the responses to noise of AD/HD children during the CPT.


Subject(s)
Acoustic Stimulation , Attention Deficit Disorder with Hyperactivity/diagnosis , Attention , Noise , Photic Stimulation , Aging , Child , Humans , Neuropsychological Tests , Reference Values , Software
SELECTION OF CITATIONS
SEARCH DETAIL
...