The Lck Tyrosine Kinase Is Expressed in Brain Neurons

Abstract: The lck gene product, p56^lck, is a member of the src-related family of protein tyrosine kinases. It is known as lymphocyte specific and involved in thymocyte development and in the immune response mediated by the T cell receptor. We report that the lck gene is also expressed in adult mouse CNS and that brain p56^lck is similar to the thymus protein. In situ hybridization and immunohistochemistry show that the lck gene is expressed in neurons throughout the brain in distinct regions, including hippocampus and cerebellum. In primary cultures from fetal mouse brain, neuronal cells are immunoreactive to Lck antiserum. This suggests that the lck gene product might be involved in a new signal transduction pathway in mouse brain.     

The role of PKCζ in amikacin-induced apoptosis in the cochlea: Prevention by aspirin

Aminoglycoside antibiotics are ototoxic, inducing irreversible sensorineural hearing loss mediated by oxidative and excitotoxic stresses. The NF-κB pathway is involved in the response to aminoglycoside damage in the cochlea. However, the molecular mechanisms of this ototoxicity remain unclear. We investigated the expression of PKCζ, a key regulator of NF-κB activation, in response to aminoglycoside treatment. Amikacin induced PKCζ cleavage and nuclear translocation. These events were concomitant with chromatin condensation and paralleled the decrease in NF-κB (p65) levels in the nucleus. Amikacin also induced the nuclear translocation of apoptotic inducing factor (AIF). Prior treatment with aspirin prevented PKCζ cleavage and nuclear translocation. Thus, aspirin counteracts the early effects of amikacin, thereby protecting hair cells and spiral ganglion neurons. These results demonstrate that PKCζ acts as sentinel connecting specific survival pathways to mediate cellular responses to amikacin ototoxicity. E. Lecain and B. Omri both authors contributed equally.     

Modifications of protein kinase C activity and phosphorylation of lipocortin I in cultures of pig thyroid cells

When cultured in the absence of thyreostimulin (TSH), thyroid cells lose some of their differentiated functions such as iodide transport and its incorporation into thyroglobulin. In the presence of TSH (0.1 mU/ml), these differentiated functions are preserved ("TSH cells"). The addition of tetradecanoyl phorbol 13 acetate (TPA) inhibits some differentiated functions of the cells and provokes important modifications of bio-signalling pathways. The protein kinase C (pKC) activity, unchanged in "control" and "TSH cells", was dramatically modified in TPA treated cells. After translocation, the pKC activity was down-regulated and the phosphorylation of its endogenous substrates (35-38 kDa) disappeared. Among these substrates, we identified the lipocortin I (LC I) (35 kDa), a phospholipase A2 inhibitory protein related to the Ca2+ binding protein family. By monodimensional electrophoresis (PAGE-SDS) and western-blot, we evidenced the presence of LCI in cytosols and particulate extracts. By 2 dimensional electrophoresis (PAGE-SDS and IEF) and western-blot we identified a phosphorylated and unphosphorylated LCI protein. The phosphorylation of LCI by pKC decreased its isoelectric point from 6.9-6.6. The modifications of pKC activity and LCI phosphorylation and the changes in the bio-signalling pathways can partly account for the loss of differentiation observed in control or TPA treated cells.     

H2S gas biological removal efficiency and bacterial community diversity in biofilter treating wastewater odor

The objective of this study was to assess the feasibility of using a biofilter system to treat hydrogen sulfide (H2S) contaminated air and to characterize its microbial community. The biofilter system was packed with peat. During the experimental work, the peat was divided in three layers (down, middle, and up). Satisfactory removal efficiencies of H2S were proved and reached 99% for the majority of the run time at an empty bed retention time (EBRT) of 60 s. The polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) method was used to uncover the changes in the microbial community between the different layers. Analysis of SSCP profiles demonstrated significant differences in community structure from a layer to another with a strong decrease in species diversity towards the up layer. It was found that the used support was suitable for microorganism growth, and may have a potential application in H2S biofiltration system.     

Down regulation effect of Rosmarinus officinalis polyphenols on cellular stress proteins in rat pheochromocytoma PC12 cells

Polyphenols are known to exhibit wide spectrum of benefit for brain health and to protect from several neurodegenerative diseases. The present study was sought to determine the neuroprotective effects of Rosmarinus officinalis' polyphenols (luteolin, carnosic acid, and rosmarinic acid) through the investigation of stress-related proteins. We carried out measurement of the expression of heat-shock protein (Hsp) 47 promoter in heat stressed Chinese hamster ovary transfected cells. We performed proteomic analysis and confirmed gene expression by real time PCR in PC12 cells. Results showed that these compounds modulated significant and different effects on the expression of 4 stress-related proteins: heat shock protein 90 α (Hsp90), Transitional endoplasmic reticulum ATPase (VCP/p97), Nucleoside diphosphate kinase (NDK), and Hypoxia up-regulated protein 1 (HYOU1)) at translational and post translational levels in PC12 cells and they downregulated the expression of Hsp47 activity in Chinese hamster transformed cells. These findings suggest that luteolin, carnosic acid, and rosmarinic acid may modulate the neuroprotective defense system against cellular stress insults and increase neuro-thermotolerance.     

Two complementary perspectives on inter-individual genetic distance

This paper examines population structure through the prism of pairwise genetic distances. Two complementary perspectives, framed as two simple questions, are explored: Q1: What is the probability that a random pair of individuals from the same local population is more genetically dissimilar than a random pair from two distinct populations? Q2: On average, how genetically different are two individuals from the same local population, in comparison with two individuals chosen from any two distinct populations? Models are developed to provide quantitative answers for the two questions, given allele frequencies across any number of markers from two diploid populations. The probability from Q1 is shown to drop to zero with increasing number of genetic markers even for very closely-related populations and rare alleles. The average genetic dissimilarity of two individuals from distinct populations diverges from the average dissimilarity of two individuals from the same population by a percentage dependent on estimates of population differentiation. This perspective also suggests a measure of population distance based on the intuitive notion of pairwise genetic distance, along with a simple method of estimation. Results from recent empirical research on inter-individual genetic distance in human populations are analyzed in the context of the theoretical framework.     

Chemical Composition and Antimicrobial Activity of Essential Oils from Scabiosa arenaria Forssk. Growing Wild in Tunisia

The essential oils isolated from three organs, i.e., fruits, stems and leaves, and flowers, of the endemic North African plant Scabiosa arenaria Forssk . were screened for their chemical composition, as well as their possible antibacterial, anticandidal, and antifungal properties. According to the GC‐FID and GC/MS analyses, 61 (99.26% of the total oil composition), 79 (98.43%), and 51 compounds (99.9%) were identified in the three oils, respectively. While α‐thujone (34.39%), camphor (17.48%), and β‐thujone (15.29%) constituted the major compounds of the fruit oil, chrysanthenone (23.43%), together with camphor (12.98%) and α‐thujone (10.7%), were the main constituents of the stem and leaf oil. In the case of the flower oil, also chrysanthenone (38.52%), camphor (11.75%), and α‐thujone (9.5%) were identified as the major compounds. Furthermore, the isolated oils were tested against 16 Gram‐positive and Gram‐negative bacteria, four Candida species, and nine phytopathogenic fungal strains. It was found that the oils exhibited interesting antibacterial and anticandidal activities, comparable to those of thymol, which was used as positive control, but no activity against the phytopathogenic fungal strains was observed.