Neutralizing antibodies induced by recombinant vaccinia virus expressing varicella-zoster virus gpIV.

Monoclonal antibodies generated against varicella-zoster virus (VZV) glycoprotein I (gpI) also recognize VZV gpIV (A. Vafai, Z. Wroblewska, R. Mahalingam, G. Cabirac, M. Wellish, M. Cisco, and D. Gilden, J. Virol. 62:2544-2551, 1988). To determine whether the virus-neutralizing activity of these antibodies belongs to gpI, gpIV, or both, the open reading frame encoding gpIV was inserted into the vaccinia virus genome. Immunoprecipitation of recombinant vaccinia virus-infected cells with anti-gpIV monoclonal antibody yielded synthesis and processing of gpIV similar to those expressed in VZV-infected cells. Antibodies raised against VVgpIV in a rabbit recognized both native gpI and gpIV and neutralized VZV infectivity. In addition, antibodies raised against recombinant vaccinia virus carrying VZV gpI neutralized VZV infection. These results indicate a structural relationship between VZV gpI and gpIV and show that gpI and gpIV each induce virus-neutralizing antibody.     

Physiological roles of the mitochondrial permeability transition pore

Neurons experience high metabolic demand during such processes as synaptic vesicle recycling, membrane potential maintenance and Ca²⁺ exchange/extrusion. The energy needs of these events are met in large part by mitochondrial production of ATP through the process of oxidative phosphorylation. The job of ATP production by the mitochondria is performed by the F₁F_O ATP synthase, a multi-protein enzyme that contains a membrane-inserted portion, an extra-membranous enzymatic portion and an extensive regulatory complex. Although required for ATP production by mitochondria, recent findings have confirmed that the membrane-confined portion of the c-subunit of the ATP synthase also houses a large conductance uncoupling channel, the mitochondrial permeability transition pore (mPTP), the persistent opening of which produces osmotic dysregulation of the inner mitochondrial membrane, uncoupling of oxidative phosphorylation and cell death. Recent advances in understanding the molecular components of mPTP and its regulatory mechanisms have determined that decreased uncoupling occurs in states of enhanced mitochondrial efficiency; relative closure of mPTP therefore contributes to cellular functions as diverse as cardiac development and synaptic efficacy.     

Isolation, structural characterization and antioxidant activity of a new water-soluble polysaccharide from Acanthophyllum bracteatum roots

ABPS-1, a new water-soluble polysaccharide with molecular weight of 26 kDa and a specific optical rotation of +170° (c 1.0, H₂O), was extracted from the roots of Acanthophyllum bracteatum by warm water and further successively purified through DEAE-cellulose A52 and Sephadex G-100 columns. Monosaccharide analysis revealed that the ABPS-1 was composed of Glc, Gal and Ara with a relative molar ratio of 1.4:5.2:1.0. Its structural features were elucidated by a combination of FT-IR, methylation and GC-MS analysis, periodate oxidation and Smith degradation, partial acid hydrolysis and ¹³C and ¹H NMR spectroscopy. The data obtained indicate that ABPS-1 possessed a backbone of α-(1 → 6)-linked Gal with branches attached to O-2 by α-1 → linked Glc and at O-3 by α-1 → linked Gal and by α-(1 → 3)-linked Ara. The in vitro antioxidant activity showed that ABPS-1 possesses DPPH radical-scavenging activity in a concentration-dependent manner with an EC₅₀ value of 2.6 mg/ml.     

“Plastic” and “static” behavior of vessel-anatomical features in Oriental beech (Fagus orientalis Lipsky) in view of xylem hydraulic conductivity

Key message

Xylem anatomical traits can be categorized into two groups: plastic properties which show a high inter-annual variability, and static characteristics which vary in a more conservative range.

Abstract

Water conduction in broad-leaved trees depends mainly on the size, number, and arrangement of vessels, which vary from year to year in response to varying exogenous factors, thus contributing to a safe and/or efficient water transport. However, the nature of such compensation is not clear; in particular, it is not obvious which traits act independently and which ones coincidentally. To better understand these inter-relations, tree-ring width (TRW), vessel-related anatomical traits, and the theoretical hydraulic conductivity were measured or modeled in the last 50 growth rings of mature Oriental beech trees growing at different altitudes in northern Iran. The study trees followed similar strategies compensating the effects of external factors by modifying their vessel-anatomical features. TRW and the number of vessels per unit of area were highly but negatively correlated and both were affected by exogenous factors. However, a decrease in vessel frequency (VF) is not a mirror effect of wider tree rings, but trees actively control the number of vessels produced. Principal component analysis revealed that the features VF, TRW and relative total conductivity were more plastic, whereas average vessel-lumen area, tree-ring porosity, and relative specific conductivity behaved more static. Moreover, we suggest that in theoretical approaches, total hydraulic conductivity rather than the specific hydraulic conductivity is a better indicator of a tree’s hydraulic behavior in a given growing season.     

A new pharmacological role for donepezil: attenuation of morphine-induced tolerance and apoptosis in rat central nervous system

Background

Tolerance to the analgesic effect of opioids is a pharmacological phenomenon that occurs after their prolonged administration. It has been shown that morphine-induced tolerance is associated with apoptosis in the central nervous system and neuroprotective agents which prevented apoptosis signaling could attenuate tolerance to the analgesic effects. On the other hand donepezil, an acetylcholinesterase inhibitor, has been reported to have neuroprotective effects. Therefore in this study, the effect of systemic administration of donepezil on morphine-induced tolerance and apoptosis in the rat cerebral cortex and lumbar spinal cord was evaluated. Various groups of rats received morphine (ip) and different doses of donepezil (0, 0.5, 1, 1.5 mg/kg/day). Nociception was assessed using tail flick apparatus. Tail flick latency was recorded when the rat shook its tail. For apoptosis assay other groups of rats received the above treatment and apoptosis was evaluated by in situ terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) method.

Results

The results showed that administration of donepezil (0.5, 1, 1.5 mg/kg, ip) delayed the morphine tolerance for 9, 12 and 17 days, respectively. Furthermore pretreatment injection of donepezil attenuated the number of apoptotic cells in the cerebral cortex and lumbar spinal cord compared to the control group.

Conclusion

In conclusion, we found that systemic administration of donepezil attenuated morphine-induced tolerance and apoptosis in the rat cerebral cortex and lumbar spinal cord.     

NAD kinase regulates the size of the NADPH pool and insulin secretion in pancreatic β-cells

NADPH is an important component of the antioxidant defense system and a proposed mediator in glucose-stimulated insulin secretion (GSIS) from pancreatic β-cells. An increase in the NADPH/NADP(+) ratio has been reported to occur within minutes following the rise in glucose concentration in β-cells. However, 30 min following the increase in glucose, the total NADPH pool also increases through a mechanism not yet characterized. NAD kinase (NADK) catalyzes the de novo formation of NADP(+) by phosphorylation of NAD(+). NAD kinases have been shown to be essential for redox regulation, oxidative stress defense, and survival in bacteria and yeast. However, studies on NADK in eukaryotic cells are scarce, and the function of this enzyme has not been described in β-cells. We employed INS-1 832/13 cells, an insulin-secreting rat β-cell line, and isolated rodent islets to investigate the role of NADK in β-cell metabolic pathways. Adenoviral-mediated overexpression of NADK resulted in a two- to threefold increase in the total NADPH pool and NADPH/NADP(+) ratio, suggesting that NADP(+) formed by the NADK-catalyzed reaction is rapidly reduced to NADPH via cytosolic reductases. This increase in the NADPH pool was accompanied by an increase in GSIS in NADK-overexpressing cells. Furthermore, NADK overexpression protected β-cells against oxidative damage by the redox cycling agent menadione and reversed menadione-mediated inhibition of GSIS. Knockdown of NADK via shRNA exerted the opposite effect on all these parameters. These data suggest that NADK kinase regulates intracellular redox and affects insulin secretion and oxidative defense in the β-cell.     

A pyoverdine from Pseudomonas putida CFML 90-51 with a Lys ε-amino link in the peptide chain

From Pseudomonas putida CFML 90-51 – a hospital isolate – a pyoverdine was obtained which is characterized by the unusual linkage by the -rather than the -amino group of Lys in the peptide chain. The structure elucidation by spectroscopic methods and degradation reactions is reported.