Structural characterization of a novel KH-domain containing plant chloroplast endonuclease.

Chlamydomonas reinhardtii is a single celled alga that undergoes apoptosis in response to UV-C irradiation. UVI31+, a novel UV-inducible DNA endonuclease in C. reinhardtii, which normally localizes near cell wall and pyrenoid regions, gets redistributed into punctate foci within the whole chloroplast, away from the pyrenoid, upon UV-stress. Solution NMR structure of the first putative UV inducible endonuclease UVI31+ revealed an α1-ß1-ß2-α2-α3-ß3 fold similar to BolA and type II KH-domain ubiquitous protein families. Three α-helices of UVI31+ constitute one side of the protein surface, which are packed to the other side, made of three-stranded ß-sheet, with intervening hydrophobic residues. A twenty-three residues long polypeptide stretch (D54-H76) connecting ß1 and ß2 strands is found to be highly flexible. Interestingly, UVI31+ recognizes the DNA primarily through its ß-sheet. We propose that the catalytic triad residues involving Ser114, His95 and Thr116 facilitate DNA endonuclease activity of UVI31+. Further, decreased endonuclease activity of the S114A mutant is consistent with the direct participation of Ser114 in the catalysis. This study provides the first structural description of a plant chloroplast endonuclease that is regulated by UV-stress response.

[Primary leptomeningeal sarcomatosis in a 26-year-old patient]. / Primäre Leptomeninxsarkomatose bei einem 26 Jahre alten Patienten.

Primary malignant mesenchymal tumours were seen in 2.4 per cent of all autopsy cases with primary CNS-tumours. Primary leptomeningeal sarcomatosis is rare in this group of tumours. We discuss the rare disease on the basis of the case history of a 26-year-old patient.

[Primary melanoblastoma as a cause of occlusive hydrocephalus]. / Primäres Melanoblastom als Ursache eines Okklusivhydrocephalus.

Primary melanoblastomas of the Central Nervous System are comparatively rare tumors. Lumpy or diffuse forms may occur either alone or in combination. On the basis of actual case histories, diffuse cerebral and medullary melanoblastoma is presented as a rare cause of occlusive hydrocephalus.

[Correlation between clinical and paraclinical findings in brain tumors in comparison with the operation site]. / Die Korrelation zwischen den klinischen und paraklinischen Befunden bei Hirntumoren im Vergleich zum Operationssitus.

On the basis of clinical material consisting of 147 brain tumors, the authors carry out a comparative investigation involving the site of the ensuing operation to ascertain the accuracy of the clinical and paraclinical diagnoses. Computed tomographic findings were deliberately excluded with the intention of focusing on the accuracy attainable by traditional means. Clinical findings, X-ray examination of the skull, ophthalmological findings, electroencephalographic and echoencephalographic data, nuclear diagnosis, and angiographic findings were all taken into account.

Mitochondrial respiratory function as indicator of the ischemic injury of the rat kidney.

The function of mitochondria was considered to be an indicator of ischemic injury of the rat kidney, and the respiration of isolated mitochondria was measured in different metabolic states. The respiratory control index (RCI) was chosen as a parameter of mitochondrial intactness. The results indicate that normothermic in vitro ischemia leads to a rapid decrease of RCI and an almost complete loss of respiratory control within 45 min. Hypothermia during ischemic exposure proved to be an effective protection against mitochondrial injury as indicated by a prolonged coupled respiration and an RCI of about 2, even after 24 h of ischemic kidney storage. The ischemia-induced decrease of RCI was mainly due to a progressive decrease of active-state respiration, whereas the alterations of resting-state respiration were only small. The decline of active-state respiration was paralleled by a decrease of an uncoupled respiration rate. After termination of in vivo ischemia the RCI increased very slowly. Normal RCI values were not obtained until 7 days after onset of blood reflow, which supports the assumption of long-term damage due to ischemia.