To estimate the minimal gene set required to sustain bacterial life in nutritious conditions, we carried out a systematic inactivation of Bacillus subtilis genes. Among Ϸ4,100 genes of the organism, only 192 were shown to be indispensable by this or previous work. Another 79 genes were predicted to be essential. The vast majority of essential genes were categorized in relatively few domains of cell metabolism, with about half involved in information processing, one-fifth involved in the synthesis of cell envelope and the determination of cell shape and division, and one-tenth related to cell energetics. Only 4% of essential genes encode unknown functions. Most essential genes are present throughout a wide range of Bacteria, and almost 70% can also be found in Archaea and Eucarya. However, essential genes related to cell envelope, shape, division, and respiration tend to be lost from bacteria with small genomes. Unexpectedly, most genes involved in the Embden-Meyerhof-Parnas pathway are essential. Identification of unknown and unexpected essential genes opens research avenues to better understanding of processes that sustain bacterial life.

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Partial cDNAs of myb-related regulatory genes were isolated from the tetraploid Kyoho grape ( Vitis labruscana: V. labrusca x V. vinifera) and the expression patterns of the corresponding genes were studied. Since MybA gene expression is closely related to coloring and/or ripening of the berry (expression increases strongly with the commencement of coloring and berry softening, and is detected only in berry skin and flesh), full-length cDNAs for the gene were isolated from a mature-berry cDNA library. Three different species of MybA were identified from the cDNA sequences. Delivery of these cDNAs to somatic embryos of grape led to the induction of reddish-purple spots and UDP-glucose:flavonoid 3- O-glucosyltransferase (UFGT) gene expression in non-colored embryos. The UFGT transcript was not detected in control embryos, while other structural genes for anthocyanin biosynthesis were expressed in both control and pigmented embryos. In addition, introduction of the UFGT gene induced the same reddish-purple spots in embryos. In contrast, treatment with the leucoanthocyanidin dioxygenase (LDOX) gene failed to induce these spots. Our results strongly suggest that MybA genes are involved in the regulation of anthocyanin biosynthesis in the grape via expression of the UFGT gene.

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The synthesis and characterization of two dinuclear HfIV and ZrIV complexes sandwiched between 2 mono-lacunary alpha-Keggin polyoxometalates (POMs), i.e., (Et2NH2)8[{alpha-PW11O39Hf(micro-OH)(H2O)}2].7H2O (Et2NH(2)-1) and (Et2NH2)8[{alpha-PW11O39Zr(micro-OH)(H2O)}2].7H2O (Et2NH(2)-2), are described. [Note: the moieties of their polyoxoanions are abbreviated simply as and , respectively.] A pair of HfIV- and ZrIV-containing POMs belonging to the same family were herein isolated as diethylammonium salts and were unambiguously characterized by complete elemental analysis, including sodium and oxygen analyses, TG/DTA, FT-IR, single-crystal X-ray structure analysis and solution (31P and 183W) NMR spectroscopy. Polyoxoanions 1 and 2 were isostructural with each other. The central [M2(micro-OH)2(H2O)2]6+ (M=Hf, Zr) cation unit was composed of 2 edge-sharing polyhedral M units, which were linked through 2 micro-OH groups and contained 1 water molecule coordinated to each metal center. Since the mono-lacunary Keggin POM acts as an oxygen-donor quadridentate ligand, the Hf and Zr centers are 7-coordinate. It should be noted that the present 2 Keggin 2:2-type compounds, Et2NH(2)-1 and Et2NH(2)-2, undergo a reversible conversion to Keggin 1:2-type complexes [M(alpha-PW11O39)2]10-, respectively, in solution under appropriate conditions. The synthesis of Et2NH(2)-1 and Et2NH(2)-2 is based on such an interconversion. The Zr compound Et2NH(2)-2 was rigorously compared with the 3 Zr POMs (OK-1-OK-3), recently reported by Kholdeeva's group: their POMs in a different protonation-state did not contain any coordinating water molecules.

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Arabinogalactans (AGs) are branched galactans to which arabinose residues are bound as side chains and are widely distributed in plant cell walls. They can be grouped into two types based on the structures of their backbones. Type I AGs have β-1,4-galactan backbones and are often covalently linked to the rhamnogalacturonan-I region of pectins. Type II AGs have β-1,3-galactan backbones and are often covalently linked to proteins. The main enzymes involved in the degradation of AGs are endo-β-galactanases, exo-β-galactanases, and β-galactosidases, although other enzymes such as α-L-arabinofuranosidases, β-L-arabinopyranosidases, and β-D-glucuronidases are required to remove the side chains for efficient degradation of the polysaccharides. Galactanolytic enzymes have a wide variety of potential uses, including the bioconversion of AGs to fermentable sugars for production of commodity chemicals like ethanol, biobleaching of cellulose pulp, modulation of pectin properties, improving animal feed, and determining the chemical structure of AGs. This review summarizes our current knowledge about the biochemical properties and potential applications of AG-degrading enzymes.

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