Desoxyribose nucleic acid from isolated chromosome threads in experimental epidermal methylcholanthrene carcinogenesis in mice

This article does not have an abstract

Impact of the Gain/Loss Provisions of Financial Accounting Standard No. 88 on Benefit Settlements

This research analyzes the relationship between specific firm characteristics and firms' settlement/replacement plan decisions under Statement of Financial Accounting Standard No. 88 (FAS88). I examined firms that effected either (i) a settlement of their pension obligations without a benefit plan termination or (ii) a partial termination with a replacement benefit plan or (iii) a complete termination with no replacement of a benefit plan

Author response image 1. Author response

CTP Synthetase (CtpS) is a universally conserved and essential metabolic enzyme. While many enzymes form small oligomers, CtpS forms large-scale filamentous structures of unknown function in prokaryotes and eukaryotes. By simultaneously monitoring CtpS polymerization and enzymatic activity, we show that polymerization inhibits activity, and CtpS's product, CTP, induces assembly. To understand how assembly inhibits activity, we used electron microscopy to define the structure of CtpS polymers. This structure suggests that polymerization sterically hinders a conformational change necessary for CtpS activity. Structure-guided mutagenesis and mathematical modeling further indicate that coupling activity to polymerization promotes cooperative catalytic regulation. This previously uncharacterized regulatory mechanism is important for cellular function since a mutant that disrupts CtpS polymerization disrupts E. coli growth and metabolic regulation without reducing CTP levels. We propose that regulation by large-scale polymerization enables ultrasensitive control of enzymatic activity while storing an enzyme subpopulation in a conformationally restricted form that is readily activatable. DOI: http://dx.doi.org/10.7554/eLife.03638.00

Cytochemical studies of nuclear metabolism in biological systems

This article does not have an abstract

Structure of caccigenin, a new triterpenoid sapogenin from caccinia glauca savi.

This article does not have an abstract

Occurrence of 31-norcycloartanol in smilax aspera linn.

This article does not have an abstract