Cell surface expression of 27C7 by neonatal rat olfactory ensheathing cells in situ and in vitro is independent of axonal contact

Olfactory ensheathing cells (OECs) are Schwann cell-like glial cells of the olfactory system that promote neural regeneration after transplantation into the injured central nervous system. Compared to the closely related Schwann cells, however, the biological characterization of OECs has remained fragmentary. This is due to the fact that the expression of OEC-specific markers is subject to complex regulation and that intricate ultrastructural analysis is essential to determine their localization. The p75 neurotrophin receptor (p75^NTR) as the prototype OEC marker, for example, is only expressed by a minor population of neonatal rat OECs in situ. The major population carries O4-positive axonal fragments on their surface after dissociation and up-regulates p75^NTR during culturing (Wewetzer et al. in Glia 49:577–587, 2005). In the present study, we investigated whether the cell surface determinant 27C7, defined by a monoclonal antibody to Schwann cells, is also expressed by neonatal rat OECs in situ and in vitro. Primary cell suspensions of the olfactory bulb displayed 27C7 expression of both p75^NTR-negative and p75^NTR-positive OECs, while immature oligodendrocytes and astrocytes were devoid of any 27C7 labeling. This together with the finding that the intrafascicular OECs of the olfactory nerves in the mucosa expressed 27C7 but not p75^NTR, suggests that 27C7 was expressed by the entire OEC population in situ. Maintenance of OECs in the absence of olfactory neurons in organotypic slice culture up-regulated p75^NTR but did not alter 27C7 expression. It is concluded that 27C7 unlike p75^NTR is constitutively expressed by OECs and may, therefore, be a useful marker for characterization of neonatal OECs in situ and in vitro.     

Crosstalk between autophagy and DNA repair systems

Autophagy and DNA repair are two essential biological mechanisms that maintain cellular homeostasis. Impairment of these mechanisms was associated with several pathologies such as premature aging, neurodegenerative diseases, and cancer. Intrinsic or extrinsic stress stimuli (e.g., reactive oxygen species or ionizing radiation) cause DNA damage. As a biological stress response, autophagy is activated following insults that threaten DNA integrity. Hence, in collaboration with DNA damage repair and response mechanisms, autophagy contributes to the maintenance of genomic stability and integrity. Yet, connections and interactions between these two systems are not fully understood. In this review article, current status of the associations and crosstalk between autophagy and DNA repair systems is documented and discussed.     

N-acetyltransferase 2 polymorphism in patients with diabetes mellitus

The arylamine N-acetyltransferases (NATs) are a unique family of enzymes that catalyse the transfer of an acetyl group from acetyl-CoA to the terminal nitrogen of hydrazine and arylamine drugs and carcinogens. Human arylamine NATs are known to exist as two isoenzymes, NAT1 and NAT2. The objective of this study was to identify whether the genetic polymorphism of NAT2 plays a role in susceptibility to Diabetes Mellitus (DM). Ninety-seven patients with DM and 104 healthy controls were enrolled in the study. NAT2*5A, NAT2*6A, NAT2*7A/B and NAT2*14A polymorphisms were detected by using real time PCR with LightCycler (Roche Diagnostics GmbH, Mannheim, Germany). According to our data, the NAT2*5A and NAT2*6A mutant genotypes and NAT2*14A heterozygous genotype were associated with an increased risk of development of DM (OR = 47.06; 95%CI: 10.55-209.77 for NAT 2*5A, OR = 18.48; 95%CI: 3.83-89.11 for NAT2*6A and OR = 18.22; 95%CI: 6.29-52.76 for NAT2*14A). However, the NAT2*7A/B gene polymorphism carried no increased risk for developing DM disease. After grouping according to phenotypes as either slow or fast acetylators, NAT2*6A slow acetylator was found to be a significant risk factor for DM (OR = 6.09; 95%CI: 1.99-18.6, p = 0.02). The results indicate that NAT2 slow acetylator genotypes may be an important genetic determinant for DM in the Turkish population.     

In vitro anticholinesterase activity of various alkaloids

In the current study, a number of alkaloids including retamine, cytisine, and sparteine (quinolizidine-type), yohimbine and vincamine (indole-type), scopolamine and atropine (tropane-type), colchicine (tropolone-type), allantoin (imidazolidine-type), trigonelline (pyridine-type) as well as octopamine, synephrine, and capsaicin (exocyclic amine-type) were tested in vitro for their inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) at 1 mg/ml concentration by the Ellman method using an ELISA microplate reader. Among the alkaloids tested, only capsaicin exerted a remarkable inhibitory effect towards both AChE and BChE [(62.7 +/- 0.79)% and (75.3 +/- 0.98)%, respectively]. While the rest of the alkaloids did not show any significant inhibition against AChE, three of the alkaloids, namely retamine, sparteine, and yohimbine, exerted a noteworthy anti-BChE effect as compared to galanthamine, the reference drug.     

An extracellular--pepstatin insensitive acid protease produced by Thermoplasma volcanium

In this study, some parameters for the production and caseinolytic activity of an extracellular thermostable acid protease from a thermoacidophilic archaeon Thermoplasma volcanium were determined. The highest level of growth and enzyme production were detected at pH 3.0 over an incubation period of 192 h at 60 degrees C. The pH optimum for the acid protease activity was 3.0 and the enzyme was fairly stable over a broad pH range (pH 3.0-8.0). The temperature for maximum activity of the enzyme was 55 degrees C and activity remained stable between 50 degrees C and 70 degrees C. These features could be of relevance for various biotechnological applications of this enzyme. Serine-(PMSF), cysteine-(DTT), metallo-(EDTA) and aspartate-(pepstatin) protease inhibitors did not inhibit the caseinolytic activity of the enzyme. Therefore, Tp. volcanium acid protease could be a member of the pepstatin-insensitive carboxyl proteinases.     

Does Sertraline Affect Hypothalamic Food Intake Peptides in the Rat Experimental Model of Chronic Mild Stress-Induced Depression?

Neurochemical Research - Depression is a chronic, recurrent and life-threatening disease affecting approximately 15% of the world population. Depression is responsible for neuropathologies like...     

Phytochemical Content,Antidiabetic, Anticholinergic,and Antioxidant Activities of Endemic Lecokia cretica Extracts

The aim of this work was to investigate the enzyme inhibition, antioxidant activity, and phenolic compounds of Lecokia cretica (Lam .) DC. Acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and α‐glycosidase enzymes were strongly inhibited by the L. cretica extracts. IC₅₀ values for the three enzymes were found as 3.21 mg/mL, 2.1 mg/mL, and 2.07 mg/mL, respectively. Antioxidant activities were examined in both aqueous and ethanol (EtOH) extracts using CUPRAC, FRAP, and DPPH method. Also, the phenolic compounds of the endemic plant were identified and quantified by using HPLC/MS/MS. According to the results, the extracts have remarkable antioxidant activities. The most abundant phenolic acids of L. cretica in EtOH extract were determined as quinic acid (12.76 mg/kg of crude extract), chlorogenic acid (3.39 mg/kg), and malic acid (2.38 mg/kg).     

Target concentration dependence of DNA melting temperature on oligonucleotide microarrays

The design of microarrays is currently based on studies focusing on DNA hybridization reaction in bulk solution. However, the presence of a surface to which the probe strand is attached can make the solution‐based approximations invalid, resulting in sub‐optimum hybridization conditions. To determine the effect of surfaces on DNA duplex formation, the authors studied the dependence of DNA melting temperature (T_m) on target concentration. An automated system was developed to capture the melting profiles of a 25‐mer perfect‐match probe–target pair initially hybridized at 23°C. Target concentrations ranged from 0.0165 to 15 nM with different probe amounts (0.03–0.82 pmol on a surface area of 10¹⁸ Ų), a constant probe density (5 × 10¹² molecules/cm²) and spacer length (15 dT). The authors found that T_m for duplexes anchored to a surface is lower than in‐solution, and this difference increases with increasing target concentration. In a representative set, a target concentration increase from 0.5 to 15 nM with 0.82 pmol of probe on the surface resulted in a T_m decrease of 6°C when compared with a 4°C increase in solution. At very low target concentrations, a multi‐melting process was observed in low temperature domains of the curves. This was attributed to the presence of truncated or mismatch probes. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012