TAT-mediated delivery of human glutamate dehydrogenase into PC12 cells

Human glutamate dehydrogenase (GDH) gene was fused with a gene fragment encoding the nine amino acid (RKKRRQRRR) protein transduction domain of human immunodeficiency virus TAT protein in bacterial expression vector to produce genetic in-frame TAT-GDH fusion protein. The TAT-GDH protein can enter PC12 cells efficiently when added exogenously in culture media as determined by Western blot analysis and enzyme activities. Once inside the cells, the transduced denatured TAT-GDH protein showed a full activity of GDH indicating that the TAT-GDH fusion protein was correctly refolded after delivery into cells and the activities of GDH in the TAT-GDH fusion protein was not affected by the addition of the TAT sequence. TAT-GDH fusion protein and TAT itself showed no cytotoxicity in PC12 cells. Although the exact mechanism of transduction across a membrane remains unclear, the transduction activity of TAT-GDH into PC12 cells may suggest new possibilities for direct delivery of GDH into the patients with the GDH-deficient disorders.     

New species of Metacaligus (Caligidae,Copepoda) parasitic on the cutlassfish (Trichiurus lepturus) of Taiwan,with a cladistic analysis of the family Caligidae

Metacaligus latus n. sp. (Copepoda, Caligidae) is described from specimens found parasitic in the oral and gill cavities of the cutlassfish, Trichiurus lepturus Linnaeus, caught from the Strait of Taiwan and landed at Dong-Shih Fishing Port in Chiayi County, Taiwan. It is close to M. uruguayensis (Thomsen, 1949), but can be distinguished from the latter by the possession of shorter caudal rami in both sexes and wider cephalothorax and genital complex in the male. Cladistic (phylogenetic) analysis of the Family Caligidae, based on 23 selected morphological characters, revealed that Metacaligus Thomsen, 1949 is distantly related to Caligus Müller, 1758. It is a valid genus and occurs in sister-group relationship with Apogonia Cressey and Cressey, 1990.     

Growth in disorders of adrenal hyperfunction

Growth is disturbed by adrenal hypersecretion of androgens or cortisol. Androgen excess in virilizing adrenal tumours causes advanced growth and bone age. In 9 girls with virilizing tumours, mean heights at diagnosis and final heights were 1.23 +/- 0.42 and 1.3 +/- 0.37 SDS respectively. In poorly controlled CAH, excess androgens cause early epiphyseal fusion and adult short stature. Increased growth occurs only after 18 months of age, even in untreated CAH, i.e. hydrocortisone >10 mg/m(2)/day is not generally required and may suppress infantile growth, affecting childhood and adult height. Growth was studied in 19 patients, aged 6.4-17.8 years, with Cushing's disease (CD). At diagnosis, mean height SDS was -1.81 (1.2 to -4.17), 53% < -1.8 SDS, height velocity in 6 was 0.9-3.8 cm/year and mean BMI SDS 2.29 (0.7-5.06). From 1983 to 2001, CD was cured in 18 patients (61%) by transsphenoidal surgery (TSS) alone and 39% by TSS plus pituitary irradiation (RT). In 13 patients, growth hormone (GH) was assessed by ITT/glucagons at 1-108 months after cure. Four had severe GH deficiency (<9 mU/l), 7 subnormal (10-29 mU/l) and 2 normal (>30 mU/l) GH status. Subnormal GH was present in 7 subjects >2 years after TSS or RT cure. In 10 subjects, aged 12.9 +/- 3.4 years, growth after cure was studied for 9.1 +/- 5.0 years. Nine had no catch-up growth in the interval of 0.3-1.1 years after cure (mean HV 5.3 +/- 2.4 cm/year). All these had GH deficiency peak GH 0.5-20.9 mU/l, and received hGH 2.7 mg/m(2)/week, 3 with GnRHa. All 10 showed long-term catch-up growth with mean delta SDS at diagnosis (Ht SDS-target Ht SDS) -1.72 +/- 1.26 improving to -0.83 +/- 1.08 (p = 0.0005) at latest of final Ht. At diagnosis, virilization was present in 82% of 17 patients with CD. Mean SDS values of serum androstenedione, DHEA-S and testosterone were normal, i.e. 0.72 (-2.9 to 3.0), -0.8 (6.0 to 2.2), 0.7 (-7.9 to 9.5) respectively, whereas SHBG was reduced at -2.1 (-5.3 to 1.2), increasing free androgen levels. Bone age (BA) was delayed (mean 1.46 years) in 14/16 patients, suggesting cortisol excess contributed more then androgen effect to skeletal maturation. In conclusion, most paediatric patients with CD had subnormal linear growth with delayed BA. After cure by TSS or pituitary irradiation, GH deficiency was frequent and persisted for many years. Treatment with hGH induced significant long-term catch-up growth leading to reasonable final height.     

Vascular endothelial growth factor induces IP-10 chemokine expression

We have previously shown that intracavernous injection of vascular endothelial growth factor (VEGF) improved the recovery of erectile function in an arteriogenic impotence rat mode. We wished to identify genes that are affected by VEGF treatment in the penis. Specifically we examined the induction of IP-10 chemokine. Male rats were subjected to pudendal arterial ligation or sham operation. They were then treated with intracavernous injection of 4 microg of VEGF in phosphate-buffered saline (PBS) or PBS alone. At 6 and 24 h after treatment, the erectile tissue was then harvested for RNA isolation. The isolated RNA was used for microarray and RT-PCR analyses. Cultured rat cavernous smooth muscle cells (CSMC) were treated with VEGF and then subjected to RT-PCR analysis. Cultured human CSMC were treated with VEGF and then subjected to ELISA analysis. Microarray analysis detected IP-10 as an abundantly induced message in 6-h VEGF-treated tissues. This was further confirmed by RT-PCR analysis. Using cultured rat CSMC, induction of IP-10 mRNA was detectable in 1 and 2 h, but not 24 h, VEGF-treated cells. Induction of IP-10 at the protein level was observed with cultured human CSMC. Secretion of IP-10 into culture medium peaked at 4 h after treatment of human CSMC with 10 ng/ml of VEGF. Optimal VEGF dosage for IP-10 induction was 50 ng/ml when assayed with cells that were treated for 8 h.     

The Na(+)/H(+) exchanger regulatory factor 2 mediates phosphorylation of serum- and glucocorticoid-induced protein kinase 1 by 3-phosphoinositide-dependent protein kinase 1

The Na(+)/H(+) exchanger regulatory factor 2 (NHERF2/TKA-1/E3KARP) contains two PSD-95/Dlg/ZO-1 (PDZ) domains which interact with the PDZ docking motif (X-(S/T)-X-(V/L)) of proteins to mediate the assembly of transmembrane and cytosolic proteins into functional signal transduction complexes. One of the PDZ domains of NHERF2 interacts specifically with the DSLL, DSFL, and DTRL motifs present at the carboxy-termini of the 2-adrenergic receptor, the platelet-derived growth factor receptor, and the cystic fibrosis transmembrane conductance regulator, respectively. Serum- and glucocorticoid-induced protein kinase 1 (SGK1) also carries a putative PDZ-binding motif (D-S-F-L) at its carboxy tail, implicated in the specific interaction with NHERF2. There is a 3-phosphoinositide-dependent protein kinase 1 (PDK1) interacting fragment (PIF) in the tail of NHERF2. Using pull-down assays and co-transfection experiments, we demonstrated that the DSFL tail of SGK1 interacts with the first PDZ domain of NHERF2 and the PIF of NHERF2 binds to the PIF-binding pocket of PDK1 to form an SGK1-NHERF2-PDK1 complex. Formation of the protein complex promoted the phosphorylation and activation of SGK1 by PDK1. Thus, it was suggested that NHERF2 mediates the activation and phosphorylation of SGK1 by PDK1 through its first PDZ domain and PIF motif, as a novel SGK1 activation mechanism.     

GSH-dependent peroxidase activity of the rice (Oryza sativa) glutaredoxin,a thioltransferase

Glutaredoxin (Grx) is a 12-kDa thioltransferase that reduces disulfide bonds of other proteins and maintains the redox potential of cells. In addition to its oxidoreductase activity, we report here that a rice Grx (OsGrx) can also function as a GSH-dependent peroxidase. Because of this antioxidant activity, OsGrx protects glutamine synthetase from oxidative damage. Individually replacing the conserved Cys residues in OsGrx with Ser shows that Cys(23), but not Cys(26), is essential for the thioltransferase and GSH-dependent peroxidase activities. Kinetic characterization of OsGrx reveals that the maximal catalytic efficiency (V(max)/K(m)) is obtained with cumene hydroperoxide rather than H(2)O(2) or t-butyl hydroperoxide.     

Activity enhancement of Cel5Z from Pectobacterium chrysanthemi PY35 by removing C-terminal region

The phytopathogenic bacterium Pectobacteium chrysanthemi PY35 secretes Cel5Z endoglucanase belonging to the glycoside hydrolase family 5 of EC 3.2.1.4. The mutation of cel5Z::Omega gene was constructed by cloning the 2.0-kb SmaI fragment containing the streptomycin/spectinomycin-resistance gene of pHP45(Omega) into the BalI site of pPY100. The insertion of Omega fragment generated a new stop codon, removing the Ser/Thr-rich linker region and the cellulose binding domain (CBD) in the C-terminal region of cel5Z gene. By subsequent subcloning from this 4.9-kb fragment (pPY1001), a 1.0-kb (pPY1002) fragment was obtained and designated as cel5Z::Omega. The cel5Z::Omega gene had an open reading frame (ORF) of 1011 bp, encoding 336 amino acids, starting with an ATG codon and ending with a new TGA stop codon. The molecular mass of the Cel5Z::Omega protein in E. coli transformant appeared to be 32 kDa by SDS-PAGE analysis in the presence of carboxymethyl-cellulose (CMC). The Cel5Z::Omega protein hydrolyzed CMC with 1.7-fold higher activity than the intact Cel5Z cellulase.     

Arginine antimetabolite L-canavanine induces apoptotic cell death in human Jurkat T cells via caspase-3 activation regulated by Bcl-2 or Bcl-xL

L-Canavanine, a natural L-arginine analog, is known to possess cytotoxicity to tumor cells in culture and experimental tumors in vivo. In this study, we first show that apoptotic cell death is associated with antitumor activity of L-canavanine against human acute leukemia Jurkat T cells. When Jurkat T cells were treated with 1.25-5.0mM L-canavanine for 36 h, apoptotic cell death accompanying several biochemical events such as caspase-3 activation, degradation of poly(ADP-ribose) polymerase (PARP), and apoptotic DNA fragmentation was induced in a dose-dependent manner; however, cytochrome c release from mitochondria was not detected. Under these conditions, the expression of Bcl-2 and its functional homolog Bcl-xL was markedly upregulated. The L-canavanine-induced caspase-3 activation, degradation of PARP, and apoptotic DNA fragmentation were suppressed by ectopic expression of Bcl-2 or Bcl-xL, both of which are known to play roles as anti-apoptotic regulators. These results demonstrate that the cytotoxic effect of L-canavanine on Jurkat T cells is attributable to the induced apoptosis and that L-canavanine-induced apoptosis is mediated by a cytochrome c-independent caspase-3 activation pathway that can be interrupted by Bcl-2 or Bcl-xL.     

Protective effect of metallothionein-III on DNA damage in response to reactive oxygen species

Metallothionein (MT)-III is a member of a brain-specific MT family, in contrast to MT-I and MT-II that are found in most tissues and are implicated in metal ion homeostasis and as an antioxidant. To investigate the defensive role of MT-III in terms of hydroxyl radical-induced DNA damage, we used purified human MT-III. DNA damage was detected by single-strand breaks of plasmid DNA and deoxyribose degradation. In this study, we show that MT-III is able to protect against the DNA damage induced by ferric ion-nitrilotriacetic acid and H(2)O(2), and that this protective effect is inhibited by the alkylation of the sulfhydryl groups of MT-III by treatment with EDTA and N-ethylmaleimide. MT-III was also able to efficiently remove the superoxide anion, which was generated from the xanthine/xanthine oxidase system. These results strongly suggest that MT-III is involved in the protection of reactive oxygen species-induced DNA damage, probably via direct interaction with reactive oxygen species, and that MT-III acts as a neuroprotective agent.