Biomedical subjects

Hsin-I Lin

Publications and source records attributed to Hsin-I Lin.

4 recordsLinked to original sources

PubMed2006

Molecular cloning and functional identification of invertase isozymes from green bamboo Bambusa oldhamii.

Three Bo beta fruct cDNAs encoding acid invertases were cloned from shoots of the green bamboo Bambusa oldhamii. On the basis of the amino acid sequences of their products and phylogenetic analyses, Bo beta fruct1 and Bo beta fruct2 were determined to encode cell wall invertases, whereas Bo beta fruct3encodes a vacuolar invertase. The recombinant proteins encoded by Bo beta fruct2 and Bo beta fruct3 were produced in Pichia pastoris and purified to near homogeneity using ammonium sulfate fractionation and immobilized metal affinity chromatography. The pH optima, pI values, and substrate specificities of the isolated enzymes were consistent with those of plant cell wall or vacuolar invertases. The growth-dependent expression of Bo beta fruct1 and Bo beta fruct2 in the base regions of shoots underscores their roles in sucrose unloading and providing substrates for shoot growth. Its high sucrose affinity suggests that the Bo beta fruct2-encoded enzyme is important for maintaining the sucrose gradient between source and sink organs, while the predominant expression of Bo beta fruct3 in regions of active cell differentiation and expansion suggests functions in osmoregulation and cell enlargement.

Amino Acid Sequence↗

PubMed2005

A pathway for tumor necrosis factor-alpha-induced Bcl10 nuclear translocation. Bcl10 is up-regulated by NF-kappaB and phosphorylated by Akt1 and then complexes with Bcl3 to enter the nucleus.

Bcl10 overexpression and nuclear translocation were originally identified in mucosa-associated lymphoid tissue lymphoma with t(1;14)(p32;q32) chromosome translocation. DNA amplification of Bcl10 was also found in other solid tumors. We have recently shown that nuclear translocation of Bcl10 is a specific molecular determinant of Helicobacter pylori-independent mucosa-associated lymphoid tissue lymphoma (Kuo, S.-H., Chen, L. T., Yeh, K.-H., Wu, M. S., Hsu, H. C., Yeh, P. Y., Mao, T. L., Chen, C. L., Doong, S. L., Lin, J. T., and Cheng, A.-L. (2004) J. Clin. Oncol. 22, 3491-3497). However, the molecular mechanism of Bcl10 nuclear translocation remains unknown. In this study, we observed that tumor necrosis factor-alpha (TNFalpha) up-regulates the expression of Bcl10 and induces a fraction of Bcl10 nuclear translocation in human breast carcinoma MCF7 cells. Chromatin immunoprecipitation assays and electrophoretic mobility shift assays indicated that an NF-kappaB-binding site resides in the Bcl10 5 '-untranslated region. This study also demonstrates that Akt1, activated by TNFalpha, phosphorylates Bcl10 at Ser218 and Ser231 and that phosphorylated Bcl10 subsequently complexes with Bcl3 to enter the nucleus. Either inhibition of Akt1 or depletion of Bcl3 blocks Bcl10 nuclear translocation. In summary, these findings characterize a molecular linkage that directs Bcl10 nuclear translocation in response to TNFalpha treatment.

Active Transport, Cell Nucleus↗

PubMed2005

Tumor necrosis factor-alpha and interleukin-18 modulate neuronal cell fate in embryonic neural progenitor culture.

Neural progenitor cells (NPCs) in developing and adult CNS are capable of giving rise to various neuronal and glial cell populations. Neurogenesis in the adult hippocampus has been found to be inhibited by a proinflammatory cytokine, interleukin-6 (IL-6), suggesting that activated microglia in the inflamed brain may control neurogenesis. Yet, little is known about the effect of microglia-derived factors on the cell fate of embryonic NPCs. In this study, we show that neurons with betaIII-tubulin immunoreactivity in the NPC culture were reduced by the condition media collected from microglia treated with endotoxin lipopolysaccharide (LPS/M-CM). Treatment with pentoxifylline (PTX), an inhibitor for tumor necrosis factor-alpha (TNF-alpha) secretion from LPS-activated microglia, blocked the reduction of betaIII-tubulin+ cells in NPC culture. Furthermore, treatment of NPCs with interleukin-18 (IL-18), a recently discovered proinflammatory cytokine, also decreased the number of betaIII-tubulin+ cells in a dose- and time-dependent manner. Surprisingly, we also observed that the remaining betaIII-tubulin+ cells in the LPS/M-CM-treated culture exhibited more branching neurites. Thus, the activated microglia-derived cytokines, TNF-alpha and IL-18, may either inhibit the neuronal differentiation or induce neuronal cell death in the NPC culture, whereas these cells may also produce factors to improve the neurite branching in the NPC culture.

Animals↗

PubMed2004

A bayesian approach to parameter estimation for a crayfish (Procambarus spp.) bioaccumulation model.

Bioaccumulation models are used to describe chemical uptake and clearances by organisms. Averaged input parameter values are traditionally used and yield point estimates of model outputs. Hence, the uncertainty and variability of model predictions are ignored. Probabilistic modeling approaches, such as Monte Carlo simulation and the Bayesian method, have been recommended by the U.S. Environmental Protection Agency to provide a quantitative description of the degree of uncertainty and/or variability in risk estimates in ecological hazards and human health effects. In this study, a Bayesian analysis was conducted to account for the combined uncertainty and variability of model parameters in a crayfish bioaccumulation model. After a 5-d exposure in the LaBranche Wetlands (LA, USA), crayfish were analyzed for polycyclic aromatic hydrocarbon concentrations and lipid fractions. The posterior distribution of model parameters were derived from the joint posterior parameter distributions using a Markov chain Monte Carlo approach and the experimental data. The results were then used to predict the distribution of chrysene concentration versus time in the crayfish to compare the predicted ranges at the different study sites.

Animals↗