Transfer of rps19 to the nucleus involves the gain of an RNP-binding motif which may functionally replace RPS13 in Arabidopsis mitochondria.

The discovery of disrupted rps19 genes in Arabidopsis mitochondria prompted speculation about the transfer to the nuclear compartment. We here describe the functional gene transfer of rps19 into the nucleus of Arabidopsis. Molecular cloning and sequence analysis of rps19 show that the nuclear gene encodes a long N-terminal extension. Import studies of the precursor protein indicate that only a small part of this extension is cleaved off during import. The larger part of the extension, which shows high similarity to conserved RNA-binding domains of the RNP-CS type, became part of the S19 protein. In the Escherichia coli ribosome S19 forms an RNA-binding complex as heterodimer with S13. By using immuno-analysis and import studies we show that a eubacterial-like S13 protein is absent from Arabidopsis mitochondria, and is not substituted by either a chloroplastic or a cytosolic homologue of this ribosomal protein. We therefore propose that either a highly diverged or missing RPS13 has been functionally replaced by an RNP domain that most likely derived from a glycine-rich RNA-binding protein. These results represent the first case of a functional replacement of a ribosomal protein by a common RNA-binding domain and offer a new view on the flexibility of biological systems in using well-adapted functional domains for different jobs.     

A bacterial model for studying effects of human mutations in vivo: Escherichia coli strains mimicking a common polymorphism in the human MTHFR gene

A simple bacterial model for studying effects of human mutations in vivo, when homologous genes exist in bacterial and human cells, is presented. We have constructed Escherichia coli strains bearing different alleles of the metF gene, an ortologue of human MTHFR gene, coding for 5,10-methylenetetrahydrofolate reductase. These strains bear a null mutation in the chromosomal metF gene and different metF alleles on plasmid(s), and thus there are merozygotes mimicking wild-type homozygotes, heterozygotes and recessive mutant homozygotes. The A177V mutantion in metF corresponds to one of the most common MTHFR polymorphism, A222V, which has been shown to be associated with increased levels of homocysteine in plasma that, in turn, causes many serious medical problems. Results of relatively simple and quick experiments with these strains are compatible with previously published reports on effects of the A222V substitution in the product of MTHFR gene. In addition, these results suggest either impairment of formation of heterodimers and/or heterotetramers by wild-type and A177V metF variants or dominance of the wild-type polypepides in such structures. Moreover, positive effects of folic acid and vitamins B2 and B12 on physiology of the mutant cells, suggested on the basis of clinical studies, is confirmed. Therefore, we conclude that the bacterial model described in this report may be a useful tool in studies on human mutations.     

Mucopolysaccharidoses--biochemical mechanisms of diseases and therapeutic possibilities

Mucopolysaccharidoses (MPS) are inherited metabolic diseases from the group of lysosomal storage disorders (LSD). They are caused by genetic defects resulting in the absence or severe deficiency in one of lysosmal hydrolases involved in degradation of glycosaminoglycans (GAG). Partially degraded GAGs are accumulated in lysosomes, causing dysfunction of cells, tissues and organs. Last years did bring some breakthrough discoveries, which were important to understand biochemical mechanisms of MPS appearance and course, as well as to develop therapeutic procedures for these inherited metabolic disorders.     

Fortpflanzungsverhalten des Kamm-Talegalla (Aepypodius arfakianus Salvad.)

Zusammenfassung Das Verhalten eines Paares vonAepypodius arfakianus wurde während der Fortpflanzungsperiode Mai bis September 1985 im Vogelpark Walsrode untersucht. Der Bruthügel wurde nur vom gebaut und instand gehalten. In die Voliere eingebrachtes Laub wurde vom durch systematisches Rückwärtsscharren auf den Hügel gebracht. Balzverhalten trat eng gekoppelt mit dem Öffnen des Hügels während der frühen Morgenstunden auf. Kopulationen wurden auf dem Hügel vollzogen und fanden vermehrt an den Tagen der Eiablage statt. In den frühen Morgenstunden wurde der Hügel verstärkt bei sonnigem warmem Wetter geöffnet. Eine Korrelation zwischen Dauer der Hügelöffnung und Außentemperatur ist im gemäßigten mitteleuropäischen Klima nicht feststellbar. Vom 7. Mai bis 1. September legte das insgesamt 20 Eier, mehr als das Dreifache seines Körpergewichts. Der durchschnittliche Legeabstand betrug 6 Tage. Die Eier wogen im Durchschnitt 183,4 g und wurden zwischen 25 und 50 cm tief im Hügel vergraben. Die Beziehungen zwischen Brutmethode und Eheform der Megapodiiden wird diskutiert.

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Reproductive behaviour ofAepypodius arfakianus

Summary The behaviour of a pair ofAepypodius arfakianus was studied during the breeding season from May to Sepember 1985 in Walsrode Bird Park. The building and maintenance of the nest-mound is the responsibility of the . Any foliage introduced into the aviary was moved onto the mound by the by means of systematic backward-scraping movements. Display activity was closely associated with the opening of the mound in the early morning. Copulation takes place on the mound and is carried out with increased frequency on days when egg-laying occurs. Early morning mound-opening activity intensifies in warm, sunny weather. No correlation, however, can be established between ambient temperature and duration of mound opening in the moderate Central-European climate. The laid 20 eggs between 7th May and 1st September, which represented more than three times his own weight. The average length of time between eggs laid was 6 days. The eggs were buried between 25 and 50 cm deep in the mound; their average mass was 183,4 g. The interrelationships between incubation methods and mating system in the Megapods are discussed.

     

Baseline Magnetic Resonance Imaging of the Optic Nerve Provides Limited Predictive Information on Short-Term Recovery after Acute Optic Neuritis

Background

In acute optic neuritis, magnetic resonance imaging (MRI) may help to confirm the diagnosis as well as to exclude alternative diagnoses. Yet, little is known on the value of optic nerve imaging for predicting clinical symptoms or therapeutic outcome.

Purpose

To evaluate the benefit of optic nerve MRI for predicting response to appropriate therapy and recovery of visual acuity.

Methods

Clinical data as well as visual evoked potentials (VEP) and MRI results of 104 patients, who were treated at the Department of Neurology with clinically definite optic neuritis between December 2010 and September 2012 were retrospectively reviewed including a follow up within 14 days.

Results

Both length of the Gd enhancing lesion (r = -0.38; p = 0.001) and the T2 lesion (r = -0.25; p = 0.03) of the optic nerve in acute optic neuritis showed a medium correlation with visual acuity after treatment. Although visual acuity pre-treatment was little but nonsignificantly lower if Gd enhancement of the optic nerve was detected via orbital MRI, improvement of visual acuity after adequate therapy was significantly better (0.40 vs. 0.24; p = 0.04). Intraorbitally located Gd enhancing lesions were associated with worse visual improvement compared to canalicular, intracranial and chiasmal lesions (0.35 vs. 0.54; p = 0.02).

Conclusion

Orbital MRI is a broadly available, valuable tool for predicting the improvement of visual function. While the accurate individual prediction of long-term outcomes after appropriate therapy still remains difficult, lesion length of Gd enhancement and T2 lesion contribute to its prediction and a better short-term visual outcome may be associated with detection and localization of Gd enhancement along the optic nerve.