Quantitative evaluation of protocorm growth and fungal colonization in Bletilla striata (Orchidaceae) reveals less-productive symbiosis with a non-native symbiotic fungus

Quantitative evaluation of symbiotic cells in Pecteilis radiata protocorm. (a) Symbiotic cells with hyphal coils in P. radiata protocorm. Scale bars, 50 Οm. (b) Ratio of the number of symbiotic cells at each stage in a symbiotic protocorm. Each value represents the average number of symbiotic cells in ten protocorms. The experiments were repeated six times with similar results. (PDF 959 kb

Structural plasticity in root-fungal symbioses: diverse interactions lead to improved plant fitness

Root-fungal symbioses such as mycorrhizas and endophytes are key components of terrestrial ecosystems. Diverse in trophy habits (obligate, facultative or hemibiotrophs) and symbiotic relations (from mutualism to parasitism), these associations also show great variability in their root colonization and nutritional strategies. Specialized interface structures such as arbuscules and Hartig nets are formed by certain associations while others are restricted to non-specialized intercellular or intracellular hyphae in roots. In either case, there are documented examples of active nutrient exchange, reinforcing the fact that specialized structures used to define specific mycorrhizal associations are not essential for reciprocal exchange of nutrients and plant growth promotion. In feremycorrhiza (with Austroboletus occidentalis and eucalypts), the fungal partner markedly enhances plant growth and nutrient acquisition without colonizing roots, emphasizing that a conventional focus on structural form of associations may have resulted in important functional components of rhizospheres being overlooked. In support of this viewpoint, mycobiome studies using the state-of-the-art DNA sequencing technologies have unearthed much more complexity in root-fungal relationships than those discovered using the traditional morphology based approaches. In this review, we explore the existing literature and most recent findings surrounding structure, functioning, and ecology of root-fungal symbiosis, which highlight the fact that plant fitness can be altered by taxonomically/ecologically diverse fungal symbionts regardless of root colonization and interface specialization. Furthermore, transition from saprotrophy to biotrophy seems to be a common event that occurs in diverse fungal lineages (consisting of root endophytes, soil saprotrophs, wood decayers etc.), and which may be accompanied by development of specialized interface structures and/or mycorrhiza-like effects on plant growth and nutrition

Regulation of Type IV Collagen α Chains of Glomerular Epithelial Cells in Diabetic Conditions

An early feature of diabetic nephropathy is the alteration of the glomerular basement membrane (GBM), which may result in microalbuminuria, subsequent macroproteinuria, and eventual chronic renal failure. Although type IV collagen is the main component of thickened GBM in diabetic nephropathy, cellular metabolism of each α chains of type IV collagen has not been well studied. To investigate the regulation of α(IV) chains in diabetic conditions, we examined whether glucose and advanced glycosylation endproduct (AGE) regulate the metabolism of each α(IV) chains in the diabetic tissue and glomerular epithelial cells (GEpC). Glomerular collagen α3(IV) and α5(IV) chains protein were higher and more intense in immunofluorescence staining according to diabetic durations compared to controls. In vitro, mainly high glucose and partly AGE usually increased total collagen protein of GEpC by [3H]-proline incorporation assay and each α(IV) chain proteins including α1(IV), α3(IV), and α5(IV) in time-dependent and subchain-specific manners. However, the changes of each α(IV) chains mRNA expression was not well correlated to the those of each chain proteins. The present findings suggest that the metabolism of individual α(IV) chains of GBM is differentially regulated in diabetic conditions and those changes might be induced not only by transcriptional level but also by post-translational modifications

Chestnut as a Food Allergen: Identification of Major Allergens

To evaluate the clinical significance of chestnut as a food allergen in Korea, skin prick test and ELISA were done in 1,738 patients with respiratory allergies. To identify the IgE binding components, IgE-immunoblotting, 2D IgE-immunoblotting and MALDI-TOF were performed. To observe the effects of digestive enzymes and a boiling treatment, simulated gastric fluid (SGF) and simulated intestinal fluids (SIF) were incubated with chestnut extracts, and IgE-immunoblotting were then repeated. Skin prick test revealed that 56 (3.2%) patients showed more than 2+ of allergen to histamine ratio to chestnut. Among the 21 IgE binding components, 9 bands were found in more than 50% of the sera tested and the 24 kDa protein had the highest binding intensity. The amino acid sequence of the 24 kDa protein (pI 6.3) had homology with legume protein of oak tree. SGF, SIF and boiling treatment were able to suppress the IgE binding components. In conclusion, chestnut ingestion was shown to induce IgE mediated responses with a 3.2% sensitization rate. Twenty one IgE binding components and one new allergen (the 24 kDa protein) were identified. Digestive enzymes and boiling treatment were able to decrease the allergenic potency

Association of Angiotensin II Type 2 Receptor Gene A1818T Polymorphism with Progression of Immunoglobulin A Nephropathy in Korean Patients

We determined the relationship between the progression of immunoglobulin A nephropathy (IgAN) and the A1818T polymorphism in intron 2 of Angiotensin II type 2 receptor (AT2R) gene, which might play protective roles in the pathogenesis of IgAN. Patients with biopsy-proven IgAN were recruited from the registry of the Progressive REnal disease and Medical Informatics and gEnomics Research (PREMIER) which was sponsored by the Korean Society of Nephrology. A1818T polymorphism of AT2R gene was analyzed with PCR-RFLP method and the association with the progression of IgAN, which was defined as over 50% increase in baseline serum creatinine level, was analyzed with survival analysis. Among the 480 patients followed for more than 10 months, the group without T allele had significantly higher rates of progression of IgAN than the group with T allele (11.4% vs. 3.9%, p=0.024), although there were no significant differences in the baseline variables such as initial serum creatinine level, the degree of proteinuria, and blood pressure. In the Cox's proportional hazard model, the hazard ratio of disease progression in the patients with T allele was 0.221 (95% confidence interval for Exp(B): 0.052-0.940, p=0.041) compared to that of without T allele. In conclusion, A1818T polymorphism of AT2R gene was associated with the progression of IgAN

エリンギ(Pleurotus eryngii)の子実態における糖質および糖質分解酵素の特徴

Carbohydrate components and their related carbohydrate activities in a homogenized preparation of the fruit body of king oyster mushroom (eryngii), Pleurotus eryngii, were studied in detail. The low-molecular weight fractions contained a significant amount of trehalose compared with other constituents of mono-saccharides, and its concentration was 18.7% of the dry weight. Polysaccharides in the high-molecular weight fraction were separated into four fractions, A~D, which were analyzed for the yields and sugar components. The polysaccharide fractions were also analyzed by the ion-exchange and gel-filtration column chromatography, and enzymatic hydrolysis. The results suggested that typical polysaccharide components in the fruit body of eryngii might be β-glucan and galactan, corresponding to the known results obtained by the liquid-cultured eryngii. A crude enzyme solution was prepared from the fruit body of eryngii, and various carbohydrase activities were measured using 27 substrates at pH 5.2, 6.5 and 7.8. A higher enzyme activity was detected for the substrates of laminarin and trehalose. Occurrence of trehalase activity correlated with the high concentration of trehalose in the fruit body of eringii

Mycoheterotrophic growth of Cephalanthera falcata (Orchidaceae) in tripartite symbioses with Thelephoraceae fungi and Quercus serrata (Fagaceae) in pot culture condition

Mixotrophy, obtaining carbon by mycoheterotrophy and photosynthesis, has been suggested in Cephalanthera species (Orchidaceae) by analyses on stable isotopes of carbon. In this study, we examined the growth of Cephalanthera falcata in pot cultured tripartite symbioses with Thelephoraceae fungi and Quercus serrata. Mycorrhizal fungi were isolated from roots of C. falcata in natural habitats. Two fungal isolates identified as Thelephoraceae were cultured and inoculated to fine roots of non-mycorrhizal seedlings of Q. serrata (Fagaceae). After the ectomycorrhizal formation, non-mycorrhizal seedlings of C. falcata were co-planted. The pots with tripartite symbioses were cultured in greenhouse for 30 months, and growth of C. falcata seedlings was examined. Fresh weight of C. falcata seedlings was significantly increased by the tripartite symbioses even in those with no shoot, thus providing further evidence for the mycoheterotrophic nature of this orchid. The achievement of seedling culture in tripartite symbioses would be valuable for conserving many forest orchids and for conducting experiments to understand their physiology and ecology