Effect of soybean ureases on seed germination and plant development

Abstract Urease catalyzes the hydrolysis of urea to ammonia and carbon dioxide. The ammonia (nitrogen (N) product of urease activity) is incorporated into organic compounds. Thus, urease is involved in N remobilization, as well as in primary N assimilation. Two urease isoforms have been described for soybean: the embryo-specific, encoded by the Eu1 gene, and the ubiquitous urease, encoded by Eu4. A third urease-encoding gene was recently identified, designated Eu5, which encodes the putative protein product SBU-III. The present study aimed to evaluate the contribution of soybean ureases to seed germination and plant development. Analyses were performed using Eu1/Eu4/Eu5-co-suppressed transgenic plants and mutants of the Eu1 and Eu4 urease structural genes, as well as a urease-null mutant (eu3-a) that activates neither the ubiquitous nor embryo-specific ureases. The co-suppressed plants presented a developmental delay during the first month after germination; shoots and roots were significantly smaller and lighter. Slower development was observed for the double eu1-a/eu4-a mutant and the eu3-a single mutant. The N content in transgenic plants was significantly lower than in non-transgenic plants. Among the mutants, eu3-a presented the lowest and eu1-a the highest N content. Altogether, these results indicate that increased ureolytic activity plays an important role in plant development.

Research strategy of the case-control post-genome-wide association study / 天津医药

Since the first paper reported the finding of genetic variation contributing to human age-related macular de?generation by genome-wide association study (GWAS) in 2005, large number of human complex diseases associated genetic variants have been identified through GWAS method. However, the biological function of these genetic variants is not very clear. The present paper reviewed the methods of fine-mapping and the progress of the functional studies for these suscepti?bility variants. In the post GWAS Era, the study of genetic mechanisms can help us to understand the disease pathogenesis.

Neuroactivation studies using Functional Brain MRI / 대한핵의학회잡지

Functional MRI (fMRI) provides an indirect mapping of cerebral activity, based on the detection of the local blood flow and oxygenation changes following neuronal activity (Blood Oxygenation Level Dependent). fMRI allows us to study noninvasively the normal and pathological aspects of functional cortical organization. Each fMRI study compares two different states of activity. Echo-Planar Imaging is the technique that makes it possible to study the whole brain at a rapid pace. Activation maps are calculated from a statistical analysis of the local signal changes. fMRI is now becoming an essential tool in the neurofunctional evaluation of normal volunteers and many neurological patients as well as the reference method to image normal or pathologic functional brain organization.

A Functional Study of Gap Junction in GJB2 Mutations Associated with Hereditary Hearing Loss / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: GJB2 (Connexin 26), the gene of the gap-junction proteins, was found to be the main causative gene of autosomal recessive nonsyndromic hearing loss (DFNB1). Whereas 35delG was known as the major type mutation in the western countries, 235delC was reported as the specific form of mutation in Asian population. The objective of this study is to identify how two mutations (235 delC, E114G) found in the Korean population affect the function of GJB2 using the molecular biology techniques. MATERIALS AND METHODS: 235delC and E114G types of mutations were cloned in the pcDNA3 vector. HeLa cells were transfected with these cloned vectors by the liposome complex method. 1) The expression and subcellular localization of Cx26 were determined using antibodies against amino acid sequences in the intracellular loop (IL) and N-terminal (NT) portions of Cx26. 2) To analyze functions of the GJB2, we examined the lucifer yellow dye transfer between cells with scrape-loaded technique. We used the wild-type (WT) Cx26 of normal hearing as a positive control, and mock cells as a negative control. RESULTS: The immunocytochemical analysis showed that cells transfected with E114G and WT gave characteristic punctuated patterns of reaction in the cell membrane with both antibodies. However, 235delC cells were not stained with the anti-IL antibody but only with the anti-NT antibody slightly around the nucleus regions. In the functional study of GJB2, transfer of lucifer yellow dye into contiguous cells was detected in E114G but not in 235delC. CONCLUSION: The 235delC type of mutation showed loss of their targeting activity on the cell membrane. As a result, the function of gap junction channels were severely deteriorated. With the E114G type mutation, we didn't find any difference when compared with the WT transfected cells. Above data indicate that types of GJB2 mutation are closely related to the status of hearing loss due to altered function of gap junction protein.