Inhibitors such as staurosporine,H-7 or polymyxin B cannot be used in skeletal muscle to prove the role of protein kinase C on insulin action

The precise role of protein kinase C in insulin action in skeletal muscle is not well defined. Based on the fact that inhibitors of protein kinase C block some insulin effects, it has been concluded that some of the biological actions of insulin are mediated via protein kinase C. In this study, we present evidence that inhibitors of protein kinase C such as staurosporine, H-7 or polymyxin B cannot be used to ascertain the role of protein kinase C in skeletal muscle. This is based on the following experimental evidences: a) staurosporine, H-7 and polymyxin B markedly block in muscle the effect of insulin on System A transport activity; however, this effect of insulin is not mimicked in muscle by TPA-induced stimulation of protein kinase C, b) H-7 and polymyxin B block insulin action on System A transport activity in an additive manner to the inhibitory effect of phorbol esters, c) staurosporine, H-7 and polymyxin B block the effect of insulin on lactate production, a process that is activated by insulin and TPA in an additive fashion, and d) staurosporine completely blocks the tyrosine kinase activity of insulin receptors partially purified from rat skeletal muscle.Abbreviations MeAIB a-(methyl)aminoisobutyric acid - TPA 12-O-tetradecanoylphorbol-13-acetate - H-7 1-(5-isoquinolinylsulphonyl)-2-methylpiperazine     

Association between peripheral IFN-gamma producing CD8+ T-cells and disability score in relapsing-remitting multiple sclerosis

A large body of evidence supports the involvement of the immune system in the pathogenesis of multiple sclerosis (MS). Nevertheless, how the peripheral T-cells phenotypes are associated with factors such as the disability score, the effects of immunomodulatory treatments, or the activation period is poorly understood. In this study, we have centered our attention on the presence of IFN-gamma and IL-4 producing CD4+ and CD8+ T-cells in the peripheral blood of 58 relapsing-remitting MS (RRMS) patients, 48 that were stable and 10 who were in relapse period, and 30 healthy controls (HC). Our results support the existence of an independent association between the percentage of IFN-gamma producing CD8+ lymphocytes and the increased levels of disability score. Furthermore, the number of IFN-gamma producing CD8+ lymphocytes and the disability score were not correlated in patients treated with interferon-beta, evidence of its possible benefits in combating a pro-inflammatory profile. Finally, we compared the T-cell populations in RRMS patients in the stable or active period, and we found a significant decrease of IFN-gamma producing CD4+ lymphocytes in active patients. In conclusion our study supports the hypothesis that different peripheral blood T-cell phenotypes are associated with disability score or active period of the disease.     

Fluorescence in situ hybridisation coupled to ultra small immunogold detection to identify prokaryotic cells using transmission and scanning electron microscopy

We describe a method based on fluorescence in situ hybridisation (FISH) that allows the identification of individual cells by electron microscopy. We hybridised universal and specific fluorescein-labelled oligonucleotide probes to the ribosomal RNA of prokaryotic microorganisms in heterogeneous cell mixtures. We then used antibodies against fluorescein coupled to sub-nanometer gold particles to label the hybridised probes in the ribosome. After increasing the diameter of the metal particles by silver enhancement, the specific gold-silver signal was visualised by optical microscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). It is the first time that SEM is applied to the detection of gold nanoparticles hybridised to an intracellular target, such as the ribosome. The possibility to couple phylogenetic identification by FISH to cell surface and ultrastructure observation at electron microscopy resolution has promising potential applications in microbial ecology.     

Exploring anaerobic environments for cyanide and cyano-derivatives microbial degradation

Applied Microbiology and Biotechnology - Cyanide is one of the most toxic chemicals for living organisms described so far. Its toxicity is mainly based on the high affinity that cyanide presents...     

The crustacean parasites <Emphasis Type="Italic">Ellobiopsis</Emphasis> Caullery, 1910 and <Emphasis Type="Italic">Thalassomyces</Emphasis> Niezabitowski, 1913 form a monophyletic divergent clade within the Alveolata

The Ellobiopsidae are enigmatic parasites of crustaceans that have been grouped together exclusively on the basis of morphological similarities. Ultrastructural studies have revealed their affiliation within the alveolates, which was confirmed by the phylogenetic analysis of the ribosomal RNA gene (SSU rDNA) sequences of two species of Thalassomyces Niezabitowski, 1913. However, their precise systematic position within this group remains unresolved, since they could not be definitively allied with any particular alveolate group. To better determine the systematic position of ellobiopsids by molecular phylogeny, we sequenced the SSU rDNA from the type-species of the Ellobiopsidae, Ellobiopsis chattoni Caullery, 1910. We found E. chattoni infecting various copepod hosts, Acartia clausi Giesbrecht, Centropages typicus Kröyer and Clausocalanus sp., in the Bay of Marseille, NW Mediterranean Sea, which allowed us to study several stages of the parasite development. A single unicellular multinucleate specimen provided two different sequences of the SSU rDNA gene, indicating the existence of polymorphism at this locus within single individuals. Ellobiopsis Caullery, 1910 and Thalassomyces formed a very divergent and well-supported clade in phylogenetic analyses. This clade appears to be more closely related to the dinoflagellates (including the Syndiniales/Marine Alveolate Group II and the Dinokaryota) and Marine Alveolate Group I than to the other alveolates (Ciliophora, Perkinsozoa and Apicomplexa).     

Global dispersal and ancient cryptic species in the smallest marine eukaryotes

Small eukaryotic species (<1 mm) are thought to behave as prokaryotes in that, lacking geographical barriers to their dispersal due to their tiny size, they are ubiquitous. Accordingly, the absence of geographical insulation would imply the existence of a relatively small number of microeukaryotic species. To test these ideas, we sequenced and compared several nuclear, mitochondrial, and chloroplast genes from the isolates of a marine picoeukaryotic alga (approximately 2 microm), Micromonas pusilla, collected worldwide. Independent and combined phylogenetic analyses demonstrate that this traditional single morphospecies actually comprises several independent lineages, some of which are shown to be ubiquitous in oceans. However, while some lineages group closely related strains, others form distant clusters, revealing the existence of cryptic species. Moreover, molecular dating using a relaxed clock suggests that their first diversification may have started as early as during the Late Cretaceous (approximately 65 MYA), implying that "M. pusilla" is the oldest group of cryptic species known to date. Our results illustrate that global dispersal of a picoeukaryote is possible in oceans, but this does not imply a reduced species number. On the contrary, we show that the morphospecies concept is untenable because it overlooks a large genetic and species diversity and may lead to incorrect biological assumptions.     

Mechanisms of genetic robustness in RNA viruses

Two key features of RNA viruses are their compacted genomes and their high mutation rate. Accordingly, deleterious mutations are common and have an enormous impact on viral fitness. In their multicellular hosts, robustness can be achieved by genomic redundancy, including gene duplication, diploidy, alternative metabolic pathways and biochemical buffering mechanisms. However, here we review evidence suggesting that during RNA virus evolution, alternative robustness mechanisms may have been selected. After briefly describing how genetic robustness can be quantified, we discuss mechanisms of intrinsic robustness arising as consequences of RNA-genome architecture, replication peculiarities and quasi-species population dynamics. These intrinsic robustness mechanisms operate efficiently at the population level, despite the mutational sensitivity shown by individual genomes. Finally, we discuss the possibility that viruses might exploit cellular buffering mechanisms for their own benefit, producing a sort of extrinsic robustness.