Fate of a larch unedited tRNA precursor expressed in potato mitochondria.

Abstract In higher plant mitochondria, post-transcriptional C to U conversion known as editing mostly affects mRNAs. However, three tRNAs were also shown to be edited. Among them, three editing sites were identified in larch mitochondrial tRNAHis. We have previously shown that only the edited version can undergo maturation in vitro. In this paper, we introduced via direct DNA uptake the edited or unedited version of larch mitochondrial trnH into isolated potato mitochondria and expressed them under the control of potato mitochondrial 18 S rRNA promoter. As expected, the edited form of larch mitochondrial tRNAHis precursor was processed in the isolated organelles. By contrast, no mature tRNAHis was detected when using the unedited version of trnH. However, precursor molecules could be characterized by reverse transcription-PCR. These data demonstrate that the potato mitochondrial editing machinery is not able to recognize these "foreign" editing sites and confirm that these unedited tRNA precursor molecules are not correctly processed in organello. As a consequence, the fate of these RNA precursor molecules is likely to be degradation. Indeed, we detected by PCR two 3′-end truncated precursor RNAs. Interestingly, both RNA species exhibit poly(A) tails, a hallmark of degradation in plant mitochondria. Taken together, these data suggest that, in plant mitochondria, a defective unedited RNA precursor that cannot be processed to give a mature stable tRNA, is degraded through a polyadenylation-dependent pathway

The \u3cem\u3eChlamydomonas\u3c/em\u3e Genome Reveals the Evolution of Key Animal and Plant Functions

Chlamydomonas reinhardtii is a unicellular green alga whose lineage diverged from land plants over 1 billion years ago. It is a model system for studying chloroplast-based photosynthesis, as well as the structure, assembly, and function of eukaryotic flagella (cilia), which were inherited from the common ancestor of plants and animals, but lost in land plants. We sequenced the ∼120-megabase nuclear genome of Chlamydomonas and performed comparative phylogenomic analyses, identifying genes encoding uncharacterized proteins that are likely associated with the function and biogenesis of chloroplasts or eukaryotic flagella. Analyses of the Chlamydomonas genome advance our understanding of the ancestral eukaryotic cell, reveal previously unknown genes associated with photosynthetic and flagellar functions, and establish links between ciliopathy and the composition and function of flagella

Colonic Biopsies to Assess the Neuropathology of Parkinson's Disease and Its Relationship with Symptoms

The presence of Lewy bodies and Lewy neurites (LN) has been demonstrated in the enteric nervous system (ENS) of Parkinson's disease (PD) patients. The aims of the present research were to use routine colonoscopy biopsies (1) to analyze, in depth, enteric pathology throughout the colonic submucosal plexus (SMP), and (2) to correlate the pathological burden with neurological and gastrointestinal (GI) symptoms.A total of 10 control and 29 PD patients divided into 3 groups according to disease duration were included. PD and GI symptoms were assessed using the Unified Parkinson's Disease Rating Scale part III and the Rome III questionnaire, respectively. Four biopsies were taken from the ascending and descending colon during the course of a total colonoscopy. Immunohistochemical analysis was performed using antibodies against phosphorylated alpha-synuclein, neurofilaments NF 220 kDa (NF) and tyrosine hydroxylase (TH). The density of LN, labeled by anti-phosphorylated alpha-synuclein antibodies, was evaluated using a quantitative rating score. Lewy pathology was apparent in the colonic biopsies from 21 patients and in none of the controls. A decreased number of NF-immunoreactive neurons per ganglion was observed in the SMP of PD patients compared to controls. The amount of LN in the ENS was inversely correlated with neuronal count and positively correlated with levodopa-unresponsive features and constipation.Analysis of the ENS by routine colonoscopy biopsies is a useful tool for pre-mortem neuropathological diagnosis of PD, and also provides insight into the progression of motor and non-motor symptoms

Histoire des cuisiniers en France

Si depuis une trentaine d’années la gloire et le prestige entourent les grands chefs français, l’histoire des cuisiniers ne se confond pas avec celle des cuisiniers les plus célèbres. Le monde des cuisines comprend en effet plusieurs catégories d’« ouvriers » et d’acteurs : à côté des cuisiniers de la restauration commerciale, il y a les cuisiniers de maison bourgeoise et les cuisiniers de la restauration collective. Si importantes qu’elles soient, ces distinctions n’ont pas empêché les cuisiniers de lutter ensemble pour changer leur statut dans la société. Jusqu’à la Seconde Guerre mondiale, la condition de l’immense majorité des chefs et des cuisiniers était celle de domestiques ou d’employés. Dans les restaurants les chefs étaient placés sous l’autorité des restaurateurs, propriétaires des restaurants et des maîtres d’hôtel qui dans les salles étaient au contact direct de la clientèle. Les chefs et les cuisiniers ont été longs à s’affranchir de cette double tutelle et à gagner leur indépendance. Ils ont cherché à la fin du xixe siècle à faire reconnaître leur compétence et leur qualification professionnelle puis ils sont devenus progressivement au xxe siècle propriétaires de leurs restaurants. La médiatisation puis l’aventure de la Nouvelle Cuisine dans le dernier tiers du xxe siècle les ont mis en relation avec d’autres mondes – le show business, l’industrie et la finance – tandis que l’industrie agroalimentaire changeait complètement les conditions et les modalités d’exercice de leur métier. Quant aux cuisiniers de maisons bourgeoises, ils ont dû attendre les années soixante du xxe siècle pour acquérir le statut de salarié qui n’est plus seulement celui des cuisiniers de la restauration collective mais celui de la majorité des cuisiniers en France. Fondée sur des sources et des archives inédites, cette Histoire des cuisiniers en France aux xixe et xxe siècles est celle d’un groupe, d’un métier, d’une profession en quête d’identité et de reconnaissance

Histoire des innovations alimentaires, XIXe-XXe siècles

International audienc

La Vie de l'Institut d'Histoire du Temps Présent

Drouard Alain, Rioux Jean-Pierre. La Vie de l'Institut d'Histoire du Temps Présent. In: Bulletin de l'Institut d'Histoire du Temps Présent, n°3, mars 1981. pp. 5-9