Identification of genes differentially expressed during the growth of Bambusa oldhamii.

Bamboos are ecologically and economically important grasses, and are distinguished by their rapid growth. To identify genes associated with bamboo growth, PCR-based mRNA differential display was used to clone genes that were differentially expressed in various tissues of bamboo (Bambusa oldhamii) shoots at different growth stages. In total, 260 different cDNA sequences were obtained. These genes displayed complex expression profiles across the different tissues and growth stages as revealed by a cDNA microarray analysis. Notable among them were genes that were temporally up-regulated or down-regulated in the internode-containing region of rapidly elongating shoots. These genes might participate in the rapid elongation of the bamboo culm. Of the 36 up-regulated and 46 down-regulated genes, 16 genes and 8 genes, respectively, were predicted to encode hypothetical proteins or were unknown sequences. Aside from these, genes involved in hormonal signaling and homeostasis, stress responses, peptide processing and signaling and lignin biosynthesis composed most of the up-regulated genes; genes involved in DNA replication, nucleic acid binding and signal transduction were highly represented among the down-regulated genes. These results suggested that genes associated with plant hormonal signaling and homeostasis, peptide signaling, reactive oxygen species signaling and homeostasis, several stress-related genes and a monocot-specific unknown gene, BoMSP41, play important roles in the elongation of bamboo internodes. Multiple signaling pathways might form a complex interconnected network that controls the rapid growth of this giant grass.

Analysis of the expression of BohLOL1, which encodes an LSD1-like zinc finger protein in Bambusa oldhamii.

A cDNA, BohLOL1, encoding a protein containing three zf-LSD1 (zinc finger-Lesions Simulating Disease resistance 1) domains was cloned from growing bamboo (Bambusa oldhamii) shoots. A phylogenetic analysis revealed that BohLOL1 is a homolog of Arabidopsis LSD1 and LOL1 (LSD-one-like 1), which have been reported to act antagonistically in controlling cell death via the maintenance of reactive oxygen species homeostasis. The BohLOL1 gene was differentially expressed in various bamboo shoot tissues and was upregulated in shoots with higher rates of culm elongation. The expression level of this gene in multiple shoots of bamboo, which were cultured in vitro, was also upregulated by auxins, cytokinins, pathogen infection, 2,6-dichloroisonicotinic acid (a functional analog of salicylic acid), and hydrogen peroxide. The results suggest that BohLOL1 participates in bamboo growth and in the response to biotic stress. The DNA-binding assays and subcellular localization studies demonstrated that BohLOL1 is a nuclear DNA-binding protein. BohLOL1 might function through protein-DNA interactions and thus affect the expression of its target genes. The results of this study extend the role of plant LSD1 and LOL1 proteins from the regulation of cell death to cell growth. The growth-dependent up-regulation of BohLOL1 expression, which uniquely occurs in growing bamboo, might be one of the critical factors that contribute to the rapid growth of this remarkable plant.

Emerging importance of autoimmune hepatitis in children in Taiwan, an endemic area for viral hepatitis.

BACKGROUND: Untreated autoimmune hepatitis (AIH) can develop into liver cirrhosis, with potentially fatal outcomes. Viral hepatitis in children was endemic in Taiwan before universal hepatitis B vaccination, but AIH has rarely been reported in Taiwanese children. We performed this retrospective study to characterize the clinical features of AIH in Taiwanese children. METHODS: We enrolled children with AIH, based on the revised scoring system of the International Autoimmune Hepatitis Group (IAIHG) from 383 children hospitalized with hepatitis from January 2000 to April 2008. Other etiologies of hepatitis were excluded. RESULTS: There were three definite and six probable AIH cases. The incidence of AIH among children hospitalized with hepatitis was 2.3%. Eight children had other autoimmune diseases, including systemic lupus erythematosus (SLE) (6), discoid lupus erythematosus (DLE) (1), and autoimmune polyendocrinopathy syndrome type 1 (1). Another had biliary atresia, and AIH developed after cadaveric liver transplantation. Antinuclear antibodies ranged from 1:160-1:2560. Peak alanine aminotransferase (ALT) values were 546 +/- 188 U/L (mean +/- SD). Jaundice occurred in four patients. Liver histology in the three definite AIH patients showed chronic hepatitis with predominantly lymphoplasmacytic infiltrates in portal areas, with prominent interface activity. Treatment included prednisolone, azathioprine, and/or cyclosporine. All patients survived. ALT fell to <60 U/L after treatment. Hepatitis relapse occurred in one patient. CONCLUSION: AIH in Taiwanese children is commoner than previously thought. It is associated with other autoimmune diseases and may occur before, simultaneously with, or after other autoimmune diseases. Children with liver transplants are also at risk of AIH.

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.