This novel C-C bond formation reaction provides a new synthetic pathway for the preparation of phenanthrenequinone-type compounds and their derivatives, especially in view of the easy affordability of substituted benzil derivatives from the corresponding benzaldehydes.The evolution of the hydrogen gas was followed and measured. The rate of the gas evolution was found to be constant. This observation may indicate that the process is "layer-edge" controlled, i.e. the rate is determined by the surface area of the graphite lattice which contains ordered potassium atoms available for the reaction. This is consistent with the mechanism that we have previously described for the bimolecular reduction of ketoneslZb1. The mechanistic behavior of C8K reactions with ketones, diketones and their analogs is under further investigation.

A biofilm is an organized, resilient group of microbes where individual cells acquire properties, such as drug resistance, that are distinct from those observed in suspension cultures. Here we describe and analyze the transcriptional network controlling biofilm formation in the pathogenic yeast Candida albicans, whose biofilms are a major source of medical device-associated infections. We have combined genetic screens, genome-wide approaches, and two in vivo animal models to describe a master circuit controlling biofilm formation, composed of six transcription regulators that form a tightly woven network with ~1000 target genes. Evolutionary analysis indicates that the biofilm network has rapidly evolved: genes in the biofilm circuit are significantly weighted towards genes that arose relatively recently with ancient genes being underrepresented. This circuit provides a framework for understanding many aspects of biofilm formation by C. albicans in a mammalian host. It also provides insights into how complex cell behaviors can arise from the evolution of transcription circuits.

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To explore the mechanisms and evolution of cell-cycle control, we analyzed the position and conservation of large numbers of phosphorylation sites for the cyclin-dependent kinase Cdk1 in the budding yeast Saccharomyces cerevisiae. We combined specific chemical inhibition of Cdk1 with quantitative mass spectrometry to identify the positions of 547 phosphorylation sites on 308 Cdk1 substrates in vivo. Comparisons of these substrates with orthologs throughout the ascomycete lineage revealed that the position of most phosphorylation sites is not conserved in evolution; instead, clusters of sites shift position in rapidly evolving disordered regions. We propose that regulation of protein function by phosphorylation often depends on simple nonspecific mechanisms that disrupt or enhance protein-protein interactions. The gain or loss of phosphorylation sites in rapidly evolving regions could facilitate the evolution of kinase signaling circuits.Cyclin-dependent kinases (Cdks) drive the major events of the eukaryotic cell-division cycle (1). Comprehensive identification and analysis of Cdk substrates would enhance our understanding of cell-cycle control and provide insights into the mechanisms and evolution of regulation by phosphorylation. We therefore developed methods for comprehensive identification of the sites of Cdk1 phosphorylation on large numbers of substrates in vivo. We used quantitative mass spectrometry to identify sites at which phosphorylation decreased in vivo after specific inhibition of Cdk1 (2). We used Stable Isotope Labeling of Amino Acids in Culture (SILAC) in the cdk1-as1 yeast strain, in which Cdk1 is replaced with a mutant protein engineered to be specifically and rapidly inhibited by the pyrimidine-based inhibitor 1-NM-PP1 (3). Cells of a cdk1-as1; arg4Δ; lys1Δ strain, which require exogenous lysine and arginine to survive, were grown in medium containing lysine and arginine (the 'light' culture) or in medium supplied with arginine and lysine labeled with stable heavy isotopes of carbon and nitrogen ( 13 C and 15 N) (Fig. S1). This 'heavy' culture was treated briefly (15 min) with 10 μM 1-NM-PP1 to inactivate Cdk1-as1. The cultures were then mixed together, lysed, and subjected to trypsinization. Phosphopeptides were purified from the peptide mixture and analyzed by tandem mass spectrometry. The precise sites of phosphorylation were inferred from the mass signature of peptide ion fragments in MS/MS spectra, and the ratio of heavy to

In humans, microbial cells (including bacteria, archaea, and fungi) greatly outnumber host cells. Candida albicans is the most prevalent fungal species of the human microbiota; this species asymptomatically colonizes many areas of the body, particularly the gastrointestinal and genitourinary tracts of healthy individuals. Alterations in host immunity, stress, resident microbiota, and other factors can lead to C. albicans overgrowth, causing a wide range of infections, from superficial mucosal to hematogenously disseminated candidiasis. To date, most studies of C. albicans have been carried out in suspension cultures; however, the medical impact of C. albicans (like that of many other microorganisms) depends on its ability to thrive as a biofilm, a closely packed community of cells. Biofilms are notorious for forming on implanted medical devices, including catheters, pacemakers, dentures, and prosthetic joints, which provide a surface and sanctuary for biofilm growth. C. albicans biofilms are intrinsically resistant to conventional antifungal therapeutics, the host immune system, and other environmental perturbations, making biofilm-based infections a significant clinical challenge. Here, we review our current knowledge of biofilms formed by C. albicans and closely related fungal species.