Search

Abstract: Myocilin is a 55–57kDa secreted glycoprotein and member of the olfactomedin family, which is mutated in some forms of primary open-angle glaucoma. To assess the effects of elevated amounts of myocilin on aqueous humor outflow dynamics in an in vivo system, transgenic βB1-crystallin-MYOC mice have been developed that strongly overexpress myocilin in their eyes. The transgenic overexpression of myocilin results in an almost five-fold increase of secreted normal myocilin in the aqueous humor of βB1-crystallin-MYOC mice. In the present study, we wanted to use βB1-crystallin-MYOC as a tool to identify the response of ocular tissues to the presence of higher than normal amounts of myocilin, and to identify changes in gene expression that could help to shed light on the functional in vivo properties of myocilin. RNA was isolated from ocular tissues of βB1-crystallin-MYOC mice and wild-type littermates. Changes in gene expression were determined by hybridization of gene microarrays and confirmed by real time RT-PCR and Western blotting. The expression of genes that had been found to be differentially regulated in βB1-crystallin-MYOC mice was further analyzed in cultured human trabecular meshwork (HTM) cells treated with recombinant myocilin. Although βB1-crystallin-MYOC mice do not have an obvious phenotype, a statistically significant up- and downregulation of several distinct genes was found when compared to gene expression in wild-type littermates. Among the genes that were found to be differentially regulated were Wasl, Ceacam1, and Spon2, which are involved in cell adhesion and cell–matrix interactions. Differences in expression were also found for Six1 which encodes for a transcription factor, and for Pftk1 whose gene product is a cdc2-related protein kinase. The expression of these genes was also found to be regulated in vitro in HTM cells treated with recombinant myocilin. Substantially higher amounts in ocular tissues of βB1-crystallin-MYOC mice were found for connexin 46 and αB-crystallin. In addition, several genes that encode for olfactomedin proteins showed distinct changes in expression. Olfml3 was significantly downregulated, while Lphn1, Lphn2, and Lphn3 were significantly upregulated. Our findings support a role for myocilin in modulating cellular adhesion, and suggest functional processes that involve other proteins of the olfactomedin family. [Copyright &y& Elsevier]

[Display omitted] • Some invasive plant species, like Pontederia crassipes , could be possibly affected by climate change. • Megamelus scutellaris is one of the most commonly used biocontrol agents for P. crassipes. • As other planthoppers, M. scutellaris is expected to host obligate mutualistic organisms, known as Yeast-like symbiotes (YLS). • YLS are first reported in M. scutellaris species and their numbers are positively correlated with their host's weight. • YLS numbers increased under elevated CO 2 , in heavier females. Water hyacinth, Pontederia crassipes , is a highly invasive plant native to South America and one of the most invasive aquatic plants in the world. For its control, the planthopper Megamelus scutellaris Berg (Hemiptera: Delphacidae), a phloem feeder also native to South America has been introduced to the USA and South Africa. Considering predicted climate change scenarios, understanding their impacts on biological control agents is crucial. An intriguing yet scarcely explored subject, is the effect of climatic changes on the obligate endosymbionts associated with sap-sucking feeders. Planthoppers establish an obligate relationship with yeast-like symbiotes (YLS), unicellular fungal microorganisms that play an important role in their development, providing missing nutrients in their diet. Considering that increased atmospheric CO 2 affects plant chemical composition, this might have a direct impact on their insect host and on their number of YLS. We evaluated the effect of two different CO 2 environments: current (cCO 2 − 400 ppm) and elevated (eCO 2 − 800 ppm) on the abundance of YLS (number of YLS cells/insect) of M. scutellaris , as well as the, age structure, sex, and weight of insects. Heavier females harbored more YLS under eCO 2 which underscores the importance of the interaction of CO 2 levels and insects' weight in shaping the abundance of YLS. Additionally, there was a significant increase in the total abundance of insects for instars III to V and adults under eCO 2 conditions. However, male number significantly exceeded that of females under both CO 2 conditions. Our results suggest a potential positive impact of eCO 2 on M. scutellaris populations, which could, in turn, enhance the control of P. crassipes. [ABSTRACT FROM AUTHOR]

Abstract: Based on the analysis of its genome sequence, the ectomycorrhizal (ECM) basidiomycetous fungus Laccaria bicolor was shown to be lacking many of the major classes of secreted enzymes that depolymerize plant cell wall polysaccharides. To test whether this is also a feature of other ECM fungi, we searched a survey genome database of Amanita bisporigera with the proteins found in the secretome of Trichoderma reesei (syn. Hypocrea jecorina), a biochemically well-characterized industrial fungus. Additional proteins were also used as queries to compensate for major groups of cell-wall-degrading enzymes lacking in the secretome of T. reesei and to substantiate conclusions drawn from the T. reesei collection. By MS/MS-based “shotgun” proteomics, 80 proteins were identified in culture filtrates of T. reesei strain RUTC30 grown on corn cell walls and in a commercial “cellulase” preparation, Spezyme CP. The two T. reesei enzyme preparations were qualitatively and quantitatively similar, the most striking difference being the lack of at least five major peptidases from the commercial enzyme mixture. Based on our analysis of A. bisporigera, this ECM fungus is deficient in many major classes of cell-wall-degrading enzymes, including both glycosyl hydrolases and carbohydrate esterases. By comparison, the genomes of the saprophytic basidiomycetes Coprinopsis cinerea and Galerina marginata (using a genome survey sequence approximately equivalent in depth to that of A. bisporigera) have, like T. reesei, a much more complete complement of cell-wall-degrading enzymes. [Copyright &y& Elsevier]