Tau dephosphorylation and microfilaments disruption are upstream events of the anti‐proliferative effects of DADS in SH‐SY5Y cells

Garlic organosulphur compounds have been successfully used as redox anti-proliferative agents. In this work, we dissect the effects of diallyl disulphide (DADS) focusing on the events upstream of cell cycle arrest and apoptosis induced in neuroblastoma SH-SY5Y cells. We demonstrate that DADS is able to cause early morphological changes, cytoskeleton oxidation, microfilaments reduction and depolymerization of microtubules. These events are attenuated in cells stably overexpressing the antioxidant enzyme SOD1, suggesting that superoxide plays a crucial role in destabilizing cytoskeleton. Moreover, we evidence that the main microtubules-associated protein Tau undergoes PP1-mediated dephosphorylation as demonstrated by treatment with okadaic acid as well as by immunoreaction with anti-Tau-1 antibody, which specifically recognizes its dephosphorylated forms. Tau dephosphorylation is inhibited by the two-electron reductants NAC and GSH ester but not by SOD1. The inability of DADS to induce apoptosis in neuroblastoma-differentiated cells gives emphasis to the anti-proliferative activity of DADS, which can be regarded as a promising potent anti-neuroblastoma drug by virtue of its widespread cytoskeleton disrupting action on proliferating cells.     

The Caenorhabditis elegans Elongator Complex Regulates Neuronal α-tubulin Acetylation

Although acetylated α-tubulin is known to be a marker of stable microtubules in neurons, precise factors that regulate α-tubulin acetylation are, to date, largely unknown. Therefore, a genetic screen was employed in the nematode Caenorhabditis elegans that identified the Elongator complex as a possible regulator of α-tubulin acetylation. Detailed characterization of mutant animals revealed that the acetyltransferase activity of the Elongator is indeed required for correct acetylation of microtubules and for neuronal development. Moreover, the velocity of vesicles on microtubules was affected by mutations in Elongator. Elongator mutants also displayed defects in neurotransmitter levels. Furthermore, acetylation of α-tubulin was shown to act as a novel signal for the fine-tuning of microtubules dynamics by modulating α-tubulin turnover, which in turn affected neuronal shape. Given that mutations in the acetyltransferase subunit of the Elongator (Elp3) and in a scaffold subunit (Elp1) have previously been linked to human neurodegenerative diseases, namely Amyotrophic Lateral Sclerosis and Familial Dysautonomia respectively highlights the importance of this work and offers new insights to understand their etiology.     

Metabolic Profiling of Alternative NAD Biosynthetic Routes in Mouse Tissues

NAD plays essential redox and non-redox roles in cell biology. In mammals, its de novo and recycling biosynthetic pathways encompass two independent branches, the “amidated” and “deamidated” routes. Here we focused on the indispensable enzymes gating these two routes, i.e. nicotinamide mononucleotide adenylyltransferase (NMNAT), which in mammals comprises three distinct isozymes, and NAD synthetase (NADS). First, we measured the in vitro activity of the enzymes, and the levels of all their substrates and products in a number of tissues from the C57BL/6 mouse. Second, from these data, we derived in vivo estimates of enzymes''rates and quantitative contributions to NAD homeostasis. The NMNAT activity, mainly represented by nuclear NMNAT1, appears to be high and nonrate-limiting in all examined tissues, except in blood. The NADS activity, however, appears rate-limiting in lung and skeletal muscle, where its undetectable levels parallel a relative accumulation of the enzyme''s substrate NaAD (nicotinic acid adenine dinucleotide). In all tissues, the amidated NAD route was predominant, displaying highest rates in liver and kidney, and lowest in blood. In contrast, the minor deamidated route showed higher relative proportions in blood and small intestine, and higher absolute values in liver and small intestine. Such results provide the first comprehensive picture of the balance of the two alternative NAD biosynthetic routes in different mammalian tissues under physiological conditions. This fills a gap in the current knowledge of NAD biosynthesis, and provides a crucial information for the study of NAD metabolism and its role in disease.     

Specific Detection of Leuconostoc mesenteroides subsp. mesenteroides with DNA Primers Identified by Randomly Amplified Polymorphic DNA Analysis

Randomly amplified polymorphic DNA analysis using primer 239 (5′ CTGAAGCGGA 3′) was performed to characterize Leuconostoc sp. strains. All the strains of Leuconostoc mesenteroides subsp. mesenteroides (with the exception of two strains), two strains formerly identified as L. gelidum, and one strain of Leuconostoc showed a common band at about 1.1 kb. This DNA fragment was cloned and sequenced in order to verify its suitability for identifying L. mesenteroides subsp. mesenteroides strains.     

Nitrogen and phosphorus removal through laboratory batch cultures of microalga Chlorella vulgaris and cyanobacterium Planktothrix isothrix grown as monoalgal and as co-cultures

Batch cultures of the green microalga Chlorella vulgaris and cyanobacterium Planktothrix isothrix and their corresponding co-cultures were grown in municipal wastewater in order to study their growth as well as the nitrogen (NH₄–N) and phosphorus (PO₄³⁻–P) removal. The cultures were grown under two irradiances of 20 and 60 μmol photons m⁻² s⁻¹ in shaken and unshaken conditions. The co-culture of unshaken Chlorella and Planktothrix showed the greatest growth under both irradiances. The monoalgal Planktotrix cultures showed better growth when unshaken than when shaken, whereas Chlorella cultures grew better when mixed, but only at the higher irradiance. The highest percentage of nitrogen removal (up to 80%) was attained by the unshaken co-cultures of Chlorella and Planktothrix. The amount of nitrogen recycled in the biomass reached up to 85% of that removed. Shaken monoalgal cultures of Chlorella showed phosphorus removal under both irradiances. They completely removed the initial phosphorus concentration (7.47 ± 0.17 mg L⁻¹) within 96 and 48 h under 20 and 60 μmol photons m⁻² s⁻¹, respectively.     

Circadian Rhythm of Cardiac Output, Peripheral Vascular Resistance, and Related Variables by a Beat-to-Beat Monitoring

This study aimed to explore the 24-h patterns of stroke volume, cardiac output, and peripheral vascular resistance along with other correlated variables, such as left ventricular ejection time, ejection velocity index, thoracic fluid index, heart rate, and blood pressure. The study was performed on 12 clinically healthy subjects by means of a noninvasive beat-to-beat monitoring using the thoracic electric bioimpedance technique associated with the automated sphygmomano-metric recording. Time data series were analyzed by means of chronobiological procedures. The results documented the occurrence of a circadian rhythm for all the variables investigated, giving relevance to the beat-to-beat bioperiodicity of cardiac output and peripheral vascular resistance. Temporal quantification of the investigated variables may be useful for a better insight of the chronophysiology of the cardiovascular apparatus.