Chitotriosidase - a putative biomarker for sporadic amyotrophic lateral sclerosis

Background

Potential biomarkers to aid diagnosis and therapy need to be identified for Amyotrophic Lateral Sclerosis, a progressive motor neuronal degenerative disorder. The present study was designed to identify the factor(s) which are differentially expressed in the cerebrospinal fluid (CSF) of patients with sporadic amyotrophic lateral sclerosis (SALS; ALS-CSF), and could be associated with the pathogenesis of this disease.

Results

Quantitative mass spectrometry of ALS-CSF and control-CSF (from orthopaedic surgical patients undergoing spinal anaesthesia) samples showed upregulation of 31 proteins in the ALS-CSF, amongst which a ten-fold increase in the levels of chitotriosidase-1 (CHIT-1) was seen compared to the controls. A seventeen-fold increase in the CHIT-1 levels was detected by ELISA, while a ten-fold elevated enzyme activity was also observed. Both these results confirmed the finding of LC-MS/MS. CHIT-1 was found to be expressed by the Iba-1 immunopositive microglia.

Conclusion

Elevated CHIT-1 levels in the ALS-CSF suggest a definitive role for the enzyme in the disease pathogenesis. Its synthesis and release from microglia into the CSF may be an aligned event of neurodegeneration. Thus, high levels of CHIT-1 signify enhanced microglial activity which may exacerbate the process of neurodegeneration. In view of the multifold increase observed in ALS-CSF, it can serve as a potential CSF biomarker for the diagnosis of SALS.     

Diversity and ecology of algae from the Nahal Qishon river,northern Israel

In 59 samples of periphyton and phytoplankton collected in 2002 - 2003 from the Nahal Qishon (Qishon River), northern Israel, we found 178 species from seven divisions of algae and cyanoprocaryotes. Diatoms, clorophytes, and cyanoprocaryotes prevail. Nitzschia and Navicula (Bacillariophyta) are the most abundant. Most of the species are cosmopolitan or widespread, except Lagynion janei (Chrysophyta), which is endemic for the Mediterranean Realm. About 17% of species (26) are new for Israel and five of them represent the first recorded genera: Crinalium endophyticum Crow, Actinocyclus normanii (Gregory) Hustedt, Rhizoclonium hieroglyphicum (Agardh) Kütz (Chlorophyta), Lagynion janei Bourelly, and Stylococcus aureus Chodat. Most of them come from a rare riverine assemblage with red alga Audouinella pygmea, as well as from the estuarine assemblage. Alkaliphiles predominate among the indicators of acidity, with few acidophiles confined to the communities under the impact of industrial wastes. Among the indicators of salinity, most numerous are the oligohalobien-indifferents and species adapted to a moderate salinity level. The relative species richness of ecological groups and the indices of saprobity are correlated with changes in conductivity, pH, and N-nitrate concentration. Indicators of organic pollution fall in the range of betameso- to alfamesosaprobic self-purification grades. Our studies show ecological significance of the Nahal Qishon as a model for a strongly disturbed aquatic ecosystem in the coastal zone of eastern Mediterranean.     

Intensive nitrogen loss over the Omani Shelf due to anammox coupled with dissimilatory nitrite reduction to ammonium

A combination of stable isotopes (¹⁵N) and molecular ecological approaches was used to investigate the vertical distribution and mechanisms of biological N₂ production along a transect from the Omani coast to the central–northeastern (NE) Arabian Sea. The Arabian Sea harbors the thickest oxygen minimum zone (OMZ) in the world''s oceans, and is considered to be a major site of oceanic nitrogen (N) loss. Short (<48 h) anoxic incubations with ¹⁵N-labeled substrates and functional gene expression analyses showed that the anammox process was highly active, whereas denitrification was hardly detectable in the OMZ over the Omani shelf at least at the time of our sampling. Anammox was coupled with dissimilatory nitrite reduction to ammonium (DNRA), resulting in the production of double-¹⁵N-labeled N₂ from ¹⁵NO₂⁻, a signal often taken as the lone evidence for denitrification in the past. Although the central–NE Arabian Sea has conventionally been regarded as the primary N-loss region, low potential N-loss rates at sporadic depths were detected at best. N-loss activities in this region likely experience high spatiotemporal variabilities as linked to the availability of organic matter. Our finding of greater N-loss associated with the more productive Omani upwelling region is consistent with results from other major OMZs. The close reliance of anammox on DNRA also highlights the need to take into account the effects of coupling N-transformations on oceanic N-loss and subsequent N-balance estimates.     

Naphthoquinone-mediated Inhibition of Lysine Acetyltransferase KAT3B/p300, Basis for Non-toxic Inhibitor Synthesis

Hydroxynaphthoquinone-based inhibitors of the lysine acetyltransferase KAT3B (p300), such as plumbagin, are relatively toxic. Here, we report that free thiol reactivity and redox cycling properties greatly contribute to the toxicity of plumbagin. A reactive 3rd position in the naphthoquinone derivatives is essential for thiol reactivity and enhances redox cycling. Using this clue, we synthesized PTK1, harboring a methyl substitution at the 3rd position of plumbagin. This molecule loses its thiol reactivity completely and its redox cycling ability to a lesser extent. Mechanistically, non-competitive, reversible binding of the inhibitor to the lysine acetyltransferase (KAT) domain of p300 is largely responsible for the acetyltransferase inhibition. Remarkably, the modified inhibitor PTK1 was a nearly non-toxic inhibitor of p300. The present report elucidates the mechanism of acetyltransferase activity inhibition by 1,4-naphthoquinones, which involves redox cycling and nucleophilic adduct formation, and it suggests possible routes of synthesis of the non-toxic inhibitor.     

Potential risk of biologic pollution associated to the introduction of <i>Pinus radiata</i> in grassland areas

Afforestation is a recommended practice to mitigate global warming. However, their implementation may generate undesirable impacts, mostly if exotic species are used. Plantations of Pinus radiata D Don in Ventania (Bs. As., Argentina) soils showed notorious increments of extractable P (Pe), which could affect the dynamic of this element as well as the degree of phosphorus saturation (GSP_Bray). The objectives of this study were: i) to quantify the GSP_Bray in Mollisols afforested with P. radiata comparing the results with those coming from adjacent, natural grassland areas (base line); ii) to evaluate the potential environmental risk induced by afforestation through the identification of a change point (PC) in the GSP_Bray indicative of a phosphate leaching increment. Treatments included mature stands of P. radiata (TB) and adjacent areas with natural grassland vegetation (TP). Samples were taken at 0-15; 15-30 and 30-45 cm soil depth, and texture, pH, total organic carbon (COT), Pe, soluble reactive phosphorus (PSR), phosphorus sorption index (ISP) and GSP_Bray were determined. The results showed a significant acidification in TB and an increase in the COT stock, indicating an additional atmospheric CO₂ sequestration by the trees. The Pe and PSR values were notoriously higher in TB, and they were reflected in a significant increment in the GSP_Bray with respect to TP. The detection of a significant PC in the GSP_Bray-PSR regression indicates higher chances of phosphate leaching in the forest stands, which could reach water courses, lakes and artificial reservoirs promoting their eutrophication. Because of the potential environmental pollution risk of biologic origin derived from the afforestation with P. radiata in Mollisols areas, their inclusion in clean development practices must be reconsidered.     

The chromosome partitioning protein, ParB, is required for cytokinesis in Caulobacter crescentus

In Caulobacter crescentus, the genes encoding the chromosome partitioning proteins, ParA and ParB, are essential. Depletion of ParB resulted in smooth filamentous cells in which DNA replication continued. Immunofluorescence microscopy revealed that the formation of FtsZ rings at the mid-cell, the earliest molecular event in the initiation of bacterial cell division, was blocked in cells lacking ParB. ParB binds sequences near the C. crescentus origin of replication. Cell cycle experiments show that the formation of bipolarly localized ParB foci, and presumably localization of the origin of replication to the cell poles, preceded the formation of FtsZ rings at the mid-cell by 20 min. These results suggest that one major function of ParA and ParB may be to regulate the initiation of cytokinesis in C. crescentus.     

The Development of Vision in the Zebrafish (Danio rerio)

We studied the development and maturation of the visual system by determining when zebrafish begin to see and to move their eyes. This information was correlated with the time courses of the development of the retina, the retinofugal projection, the retinal image, and the extraocular muscles, to obtain an integrated picture of early visual development. Two visual behaviors were monitored over 48–96 hr postfertilization (hpf). The startle response (body twitch) was evoked by an abrupt decrease in light intensity. The optokinetic response (tracking eye movements) was evoked by rotation of a striped drum. Visually evoked startle developed over 68–79 hpf, more than 20 hr after the onset of a touch-evoked startle. It was not seen in eyeless fish, excluding a role for nonretinal light senses. Tracking eye movements developed over 73–80 hpf. They were always in the direction of drum rotation, even when the fish had been light deprived from blastula stage, ruling out a “trial and error” period of learning to track the drum. The image formed by the ocular lens was examined in intact fish made transparent by suppressing the formation of melanin. The eye was initially far sighted and gradually improved, so that by 72 hpf the image plane coincided with the photoreceptor layer. The extraocular muscles assumed their adult configuration between 66 and 72 hpf. Thus, the retinal image and functional extraocular muscles appeared nearly simultaneously with the onset of tracking eye movements and probably represent the last events in the construction of this behavior.     

A conductance method for the assay and study of bacterial trimethylamine oxide reduction

Bacterial growth and trimethylamine oxide (TMAO) reduction were measured by following the change in conductance of the growth medium. The method was used as a reliable taxonomic test for the ability of bacteria to reduce TMAO. Conductance measurements were also applied to assaying the enzyme TMAO reductase in resting cells of the marine alteromonad NCMB 400: the enzyme was only active under anaerobic conditions with pyruvate, lactate and formate being good donors; the K_mTMAO was 93 ± 16 μmol/1; TMAO reductase activity was inhibited by several N -oxides including nitrite and nitrate, and was relatively resistant to cyanide. The relevance of conductance measurements and the significance of TMAO reduction are discussed.