Molecular functions and cellular roles of the ChlR1 (DDX11) helicase defective in the rare cohesinopathy Warsaw breakage syndrome

In 2010, a new recessive cohesinopathy disorder, designated Warsaw breakage syndrome (WABS), was described. The individual with WABS displayed microcephaly, pre- and postnatal growth retardation, and abnormal skin pigmentation. Cytogenetic analysis revealed mitomycin C (MMC)-induced chromosomal breakage; however, an additional sister chromatid cohesion defect was also observed. WABS is genetically linked to bi-allelic mutations in the ChlR1/DDX11 gene which encodes a protein of the conserved family of Iron–Sulfur (Fe–S) cluster DNA helicases. Mutations in the budding yeast ortholog of ChlR1, known as Chl1, were known to cause sister chromatid cohesion defects, indicating a conserved function of the gene. In 2012, three affected siblings were identified with similar symptoms to the original WABS case, and found to have a homozygous mutation in the conserved Fe–S domain of ChlR1, confirming the genetic linkage. Significantly, the clinically relevant mutations perturbed ChlR1 DNA unwinding activity. In addition to its genetic importance in human disease, ChlR1 is implicated in papillomavirus genome maintenance and cancer. Although its precise functions in genome homeostasis are still not well understood, ongoing molecular studies of ChlR1 suggest the helicase plays a critically important role in cellular replication and/or DNA repair.     

Effects of unmixed and mixed leaf litter of three species of plants on the development and growth ofPolydesmus angustus Latzel

Zusammenfassung Unter konstanten Temperatur-, Feuchtigkeits- und Lichtbedingungen entwickelt sich der MillipedierPolydesmus angustus rascher und wird grösser, wenn im Fallaub einzelner Baumarten gezüchtet, als in gemischtem Laub. Bei wechselnden Bedingungen (0–30 °C, wechselnder Feuchtigkeit und natürlichen Lichtverhältnissen) sind diese Unterschiede nur noch. für reine Eiche statistisch gesichert.

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This report is based on an investigation I carried out at the University of London, Royal Hollowey College.     

Viral adenosine triphosphatase

Summary The catalytic and immunological properties of an adenosine triphosphatase from different types of virus have been studied. The avian myeloblastosis virus has been found to be specialized in holding this enzyme in a highly active state as compared to other virus with respect to their host cell enzyme. Catalytically myeloblastosis virus and Rous virus ATPase behave alike, while that of the Reo virus is significantly different.Acknowledgment. The author would like to thank Dr. E. Racker for his continuous encouragement and helpful discussion during this piece of work.     

Binding of actinomycin D and divalent cations to lipopolysaccharides ofAgrobacterium tumefaciens as studied by fluorescence spectroscopy

Summary The binding of actinomycin D and divalent cations to lipopolysaccharides ofA. tumefaciens was studied. Fluorimetric titrations revealed 2 binding sites (low and high affinity sites) for divalent cations, and 1 high-affinity site for actinomycin D.Acknowledgment. This project was financed by the Department of Science and Technology, Govt. of India (grant No. D.O. No.11 (19)/77-SERC). To whom reprint requests should be addressed.     

Environmental and rock magnetic studies of rapid fluctuations of Asian summer monsoon during the last interglacial maximum (MIS 5e)

A systematic environmental rock magnetic study of a century-millennial scale loesspaleosol sequence of the last interglacial in the Jiuzhoutai well section, Lanzhou, on the western Loess Plateau demonstrates that Asian summer nonsoon experienced fast and large oscillations manifesting as three peaks and two valleys lasing about 1–2 ka. Valley 4 with a central age of 120.5 ka is the most evident, suggesting that summer monsoon was weakened nearly to a level in glaciations. This indicates that summer monsoon has a nature of instability in centurymillennial scale change in the last interglacial.     

Purification and properties of a heat-resistant exotoxin produced byMacrophomina phaseolina (Tassi) Goid in culture

Summary A partially purified preparation of a water-soluble, heat-resistant, nonspecific exotoxin produced by a strain ofMacrophomina phaseolina, isolated fromPhaseolus mungo L. could reduce Cu⁺⁺ ions and produced a red colour with 2,4-dinitrophenyl hydrazine reagent. It caused inhibition of seed germination, wilting of cut seedlings, stunted growth of young seedlings and loss of permeability of the cell membrane. Seedlings ofP. mungo, grown in presence of the toxin showed a slight increase in the contents of protein and total RNA over control, but a significant increase in the specific activities of F-1, 6-BP aldolase and G-6-P isomerase.     

Chromosomal pattern of asparaginase sensitive leukemia and its resistant variant

Susammenfassung Es wurde festgestellt, dass zwischen den Asparaginase-empfindlichen und resistenten Tumorzellen ein Unterschied bezüglich der Häufigkeit des Vorkommens von Marker-Chromosomen besteht.

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We are grateful to Prof.A. Levan for his kind comments, suggestions and encouragement. We are also thankful of Prof.C. G. Schmidt for the laboratory and research facilities, to MissE. Wenderhost for helping us with the photography and to Dr.D. K. Hossfeld for making the summary in German. Our thanks are due Dr.R. Bierlig of Wuppertal-Elberfeld who provided us with the leukemic tumours.     

Microbiological transformations ofβ-sitosterol and stigmasterol by a soil pseudomonad

Summary Fermentation of -sitosterol by a soil pseudomonad resulted in the formation of 4-stigmasten-3-one, 4-stigmasten-3-one-6-ol and 5-stigmasten-3, 7-diol. In case of stigmasterol the metabolites isolated and characterized were 4,22-stigmastadien-3-one, 4, 22-stigmastadien-3-one-6-ol and 5,22-stigmastadien-3, 7-diol.The soil pseudomonad strain (BS-305) is maintained at 4°C on nutrient-agar slants.