On the structure and chromosome location of the 72- and 92-kDa human type IV collagenase genes.

The 72- and 92-kDa type IV collagenases are members of a group of secreted zinc metalloproteases. Two members of this family, collagenase and stromelysin, have previously been localized to the long arm of chromosome 11. Here we assign both of the two type IV collagenase genes to human chromosome 16. By sequencing, the 72-kDa gene is shown to consist of 13 exons, 3 more than have been reported for the other members of this gene family. The extra exons encode the amino acids of the fibronectin-like domain which has so far been found in only the 72- and 92-kDa type IV collagenase. The evolutionary relationship among the members of this gene family is discussed.     

Key developmental stages of winter wheat,Triticum aestivum

Winter wheat,Triticum aestivum, is important as both a forage and grain crop in the central and southern Great Plains of the United States. A simpler system of describing winter wheat developmental stages than those currently being used is needed. Ten key developmental stages are described: 1) germination and emergence, 2) tillering, 3) leaves strongly erect, 4) node formation, 5) boot, 6) heading, 7) flowering, 8) grain filling, 9) ripening, and 10) maturity. All stages can be visually identified in the field with a minimum of training and are important with respect to grazing management, fertilizer applications, pest control, forage yield, and grain harvesting. Often no time factors can be placed on the occurrence of these stages due to environmental and cultivar differences. A discussion of stress influences on grain and forage yield is included.     

Evolutionary relationships within the fungi: analyses of nuclear small subunit rRNA sequences.

Nucleotide sequences of the small subunit ribosomal RNA (18S) gene were used to investigate evolutionary relationships within the Fungi. The inferred tree topologies are in general agreement with traditional classifications in the following ways: (1) the Chytridiomycota and Zygomycota appear to be basal groups within the Fungi. (2) The Ascomycota and Basidiomycota are a derived monophyletic group. (3) Relationships within the Ascomycota are concordant with traditional orders and divide the hemi- and euascomycetes into distinct lineages. (4) The Basidiomycota is divided between the holobasidiomycetes and phragmobasidiomycetes. Conflicts with traditional classification were limited to weakly supported branches of the tree. Strongly supported relationships were robust to minor changes in alignment, method of analysis, and various weighting schemes. Weighting, either of transversions or by site, did not convincingly improve the status of poorly supported portions of the tree. The rate of variation at particular sites does not appear to be independent of lineage, suggesting that covariation of sites may be an important phenomenon in these genes.     

Isolation of a plant glycoprotein involved with control of intercellular recognition

A recognition molecule was isolated from stigmas of S-allele genotype S₂S₂ of Brassica oleracea var. capitata L. After Sephadex chromatography, it eluted as a single symmetrical peak during diethylaminoethane-cellulose chromatography. A high degree of purity was affirmed by: sedimentation as a single peak during ultracentrifugation through 5 to 20% sucrose gradients; elution as a single peak from Sephadex G-100; visualization as a single band which stains with Coomassie blue and periodic acid Schiff reagent after electrophoresis on polyacrylamide gels. Other criteria supporting the conclusion that it is a glycoprotein are: (a) the highly purified preparation is anthrone-positive and has a Lowry protein to anthrone-positive carbohydrate ratio of 1.3; (b) the preparation contains arabinose, galactose, glucose, and mannose, although it is not precipitated by concanavalin A; (c) the immunological properties of the molecule are lost following protease treatment, and it has a molecular weight of 90,000 by Sephadex gel-filtration analysis and 54,500 by velocity sedimentation analysis.     

Moths complement bumblebee pollination of red clover: a case for day-and-night insect surveillance

Recent decades have seen a surge in awareness about insect pollinator declines. Social bees receive the most attention, but most flower-visiting species are lesser known, non-bee insects. Nocturnal flower visitors, e.g. moths, are especially difficult to observe and largely ignored in pollination studies. Clearly, achieving balanced monitoring of all pollinator taxa represents a major scientific challenge. Here, we use time-lapse cameras for season-wide, day-and-night pollinator surveillance of Trifolium pratense (L.; red clover) in an alpine grassland. We reveal the first evidence to suggest that moths, mainly Noctua pronuba (L.; large yellow underwing), pollinate this important wildflower and forage crop, providing 34% of visits (bumblebees: 61%). This is a remarkable finding; moths have received no recognition throughout a century of T. pratense pollinator research. We conclude that despite a non-negligible frequency and duration of nocturnal flower visits, nocturnal pollinators of T. pratense have been systematically overlooked. We further show how the relationship between visitation and seed set may only become clear after accounting for moth visits. As such, population trends in moths, as well as bees, could profoundly affect T. pratense seed yield. Ultimately, camera surveillance gives fair representation to non-bee pollinators and lays a foundation for automated monitoring of species interactions in future.     

A small molecule that disrupts S. Typhimurium membrane voltage without cell lysis reduces bacterial colonization of mice

As pathogenic bacteria become increasingly resistant to antibiotics, antimicrobials with mechanisms of action distinct from current clinical antibiotics are needed. Gram-negative bacteria pose a particular problem because they defend themselves against chemicals with a minimally permeable outer membrane and with efflux pumps. During infection, innate immune defense molecules increase bacterial vulnerability to chemicals by permeabilizing the outer membrane and occupying efflux pumps. Therefore, screens for compounds that reduce bacterial colonization of mammalian cells have the potential to reveal unexplored therapeutic avenues. Here we describe a new small molecule, D66, that prevents the survival of a human Gram-negative pathogen in macrophages. D66 inhibits bacterial growth under conditions wherein the bacterial outer membrane or efflux pumps are compromised, but not in standard microbiological media. The compound disrupts voltage across the bacterial inner membrane at concentrations that do not permeabilize the inner membrane or lyse cells. Selection for bacterial clones resistant to D66 activity suggested that outer membrane integrity and efflux are the two major bacterial defense mechanisms against this compound. Treatment of mammalian cells with D66 does not permeabilize the mammalian cell membrane but does cause stress, as revealed by hyperpolarization of mitochondrial membranes. Nevertheless, the compound is tolerated in mice and reduces bacterial tissue load. These data suggest that the inner membrane could be a viable target for anti-Gram-negative antimicrobials, and that disruption of bacterial membrane voltage without lysis is sufficient to enable clearance from the host.