Targeted Ablation of Oligodendrocytes Triggers Axonal Damage

Glial dysfunction has been implicated in a number of neurodegenerative diseases. In this study we investigated the consequences of glial and oligodendrocyte ablation on neuronal integrity and survival in Drosophila and adult mice, respectively. Targeted genetic ablation of glia was achieved in the adult Drosophila nervous system using the GAL80-GAL4 system. In mice, oligodendrocytes were depleted by the injection of diphtheria toxin in MOGi-Cre/iDTR double transgenic animals. Acute depletion of oligodendrocytes induced axonal injury, but did not cause neuronal cell death in mice. Ablation of glia in adult flies triggered neuronal apoptosis and resulted in a marked reduction in motor performance and lifespan. Our study shows that the targeted depletion of glia triggers secondary neurotoxicity and underscores the central contribution of glia to neuronal homeostasis. The models used in this study provide valuable systems for the investigation of therapeutic strategies to prevent axonal or neuronal damage

Izrael: Rekonstruirane procjene ukupnog izlova u Sredozemnom moru, 1950.–2010.

Over the past six decades, the Food and Agriculture Organization (FAO) has reported fisheries ‘landings’, not ‘total removals’ for Israel. Thus, public data do not include all removals, including discards, the recreational fishery, subsistence portions of the catch or Bluefin tuna catches. Moreover, FAO data inadvertently included landings by Gaza fishers in the Gaza Strip during the 1960s and 1970s. We reconstructed total removals for Israel fishing in the Mediterranean Sea using various anchor points from recent studies to account for the missing removals. We estimated total removals at slightly over 255,400 tonnes for 1950-2010, which are nearly 30% higher than the 198,136 t of Israel’s reported catch to FAO (after exclusion of data from the Gaza Strip). The major components of unreported removals were discards (over 37,400 t), dominated by the trawl fishery, and recreational removals (over 15,500 t), which account for a large and rapidly growing fishery sector in Israel. In contrast, subsistence catches (just under 4,000 t) are low, which is not unexpected for a developed country. Non-indigenous Indo-Pacific organisms are a large and growing component in the multispecies catch of Mediterranean fishers; however they appear to change species composition and mode of exploitation more than they affect the level of total removals. In the highly oligotrophic, yet fast changing Levantine Sea, the high discarding rates, use of unsustainable fishing methods and under-regulated fisheries (particularly the recreational sector) pose a threat to the integrity of the marine environment and the ecosystem services we expect from it.Tijekom proteklih šest desetljeća, FAO je davao izvješća o ulovu (iskrcajnom ulovu), ali ne i o ukupnom izlovu za Izrael. Stoga, javni podaci ne uključuju sve izlove, uključujući odbačeni ulov, ulov u rekreacijskom ribolovu, ulove u dopunskom ribolovu kao i ulove plavoperajne tune. Štoviše, FAO podaci nehotice uključuju i ulov ribara u pojasu Gaze tijekom 1960-ih i 1970- ih. Rekonstruirani su ukupni izlovi za Izraelski ribolov u Sredozemnom moru, koristeći razna polazišta iz nedavnih studija kako bi se obračunali nedostajući podaci o sveukupnom izlovu. Procijenjen ukupni izlov iznosi nešto više od 255.400 tona za razdoblje od 1950.-2010., koji je gotovo 30% veći od 198.136 t izraelskog prijavljenog ulova prema FAO (nakon odbacivanja podataka iz pojasa Gaze). Glavne komponente neprijavljenih izlova su: odbačeni ulov (preko 37.400 t), u kojem dominira koćarski ribolov, i rekreacijski izlov (preko 15.500 t), koji čini veliki i brzo rastući sektor ribarstva u Izraelu. Nasuprot tome, ulovi u dopunskom ribolovu (nešto manje od 4.000 t) su niski, što i nije neočekivano za razvijene zemlje. Strani organizmi iz Crvenog mora su velika i rastuća komponenta u ulovima mediteranskih ribara, no čini se da će isti promijeniti sastav vrsta kao i način iskorištavanja živih bogatstava znatno više nego što recimo utječu na razini ukupnog izlova. U vrlo oligotrofnom, ali i brzo mijenjajućem Levantskom moru, velike količine odbačenog ulova, postojeća uporaba neodrživih metoda ribolova kao i slabo reguliran ribolov (osobito unutar rekreativnog sektora) predstavljaju prijetnju integritetu morskog ekosustava te ujedno time i onome što možemo očekivati od njega

Proteomics and Transcriptomics Characterization of Bile Stress Response in Probiotic Lactobacillus rhamnosus GG*

Lactobacillus rhamnosus GG (GG) is a widely used and intensively studied probiotic bacterium. Although the health benefits of strain GG are well documented, the systematic exploration of mechanisms by which this strain exerts probiotic effects in the host has only recently been initiated. The ability to survive the harsh conditions of the gastrointestinal tract, including gastric juice containing bile salts, is one of the vital characteristics that enables a probiotic bacterium to transiently colonize the host. Here we used gene expression profiling at the transcriptome and proteome levels to investigate the cellular response of strain GG toward bile under defined bioreactor conditions. The analyses revealed that in response to growth of strain GG in the presence of 0.2% ox gall the transcript levels of 316 genes changed significantly (p < 0.01, t test), and 42 proteins, including both intracellular and surface-exposed proteins (i.e. surfome), were differentially abundant (p < 0.01, t test in total proteome analysis; p < 0.05, t test in surfome analysis). Protein abundance changes correlated with transcriptome level changes for 14 of these proteins. The identified proteins suggest diverse and specific changes in general stress responses as well as in cell envelope-related functions, including in pathways affecting fatty acid composition, cell surface charge, and thickness of the exopolysaccharide layer. These changes are likely to strengthen the cell envelope against bile-induced stress and signal the GG cells of gut entrance. Notably, the surfome analyses demonstrated significant reduction in the abundance of a protein catalyzing the synthesis of exopolysaccharides, whereas a protein dedicated for active removal of bile compounds from the cells was up-regulated. These findings suggest a role for these proteins in facilitating the well founded interaction of strain GG with the host mucus in the presence of sublethal doses of bile. The significance of these findings in terms of the functionality of a probiotic bacterium is discussed

Expression and sequence evolution of aromatase cyp19a1 and other sexual development genes in East African cichlid fishes

Sex determination mechanisms are highly variable across teleost fishes and sexual development is often plastic. Nevertheless, downstream factors establishing the two sexes are presumably conserved. Here, we study sequence evolution and gene expression of core genes of sexual development in a prime model system in evolutionary biology, the East African cichlid fishes. Using the available five cichlid genomes, we test for signs of positive selection in 28 genes including duplicates from the teleost whole-genome duplication, and examine the expression of these candidate genes in three cichlid species. We then focus on a particularly striking case, the A- and B-copies of the aromatase cyp19a1, and detect different evolutionary trajectories: cyp19a1A evolved under strong positive selection, whereas cyp19a1B remained conserved at the protein level, yet is subject to regulatory changes at its transcription start sites. Importantly, we find shifts in gene expression in both copies. Cyp19a1 is considered the most conserved ovary-factor in vertebrates, and in all teleosts investigated so far, cyp19a1A and cyp19a1B are expressed in ovaries and the brain, respectively. This is not the case in cichlids, where we find new expression patterns in two derived lineages: the A-copy gained a novel testis-function in the Ectodine lineage, whereas the B-copy is overexpressed in the testis of the speciest-richest cichlid group, the Haplochromini. This suggests that even key factors of sexual development, including the sex steroid pathway, are not conserved in fish, supporting the idea that flexibility in sexual determination and differentiation may be a driving force of speciation