Lumican and fibromodulin regulate the assembly of collagens into higher order fibrils in connective tissues. Here, we show that mice deficient in both of these proteoglycans manifest several clinical features of Ehlers-Danlos syndrome. The Lum ؊/؊ Fmod ؊/؊ mice are smaller than their wild type littermates and display gait abnormality, joint laxity, and age-dependent osteoarthritis. Misaligned knee patella, severe knee dysmorphogenesis, and extreme tendon weakness are the likely causes for joint laxity in the double-nulls. Fibromodulin deficiency alone leads to significant reduction in tendon stiffness in the Lum ؉/؉ Fmod ؊/؊ mice, with further loss in stiffness in a Lum gene dose-dependent way. At the protein level, we show marked increase of lumican in Fmod ؊/؊ tendons, which may partially rescue the tendon phenotype in this genotype. These results establish fibromodulin as a key regulator and lumican as a modulator of tendon strength. A disproportionate increase in small diameter immature collagen fibrils and a lack of progression to mature, large diameter fibrils in the Fmod ؊/؊ background may constitute the underlying cause of tendon weakness and suggest that fibromodulin aids fibril maturation. This study demonstrates that the collagen fibril-modifying proteoglycans, lumican and fibromodulin, are candidate genes and key players in the pathogenesis of certain types of Ehlers-Danlos syndrome and other connective tissue disorders.

An increase in small-diameter fibrils in the fibromodulin-null sclera suggests a key role for fibromodulin in the maturation and assembly of scleral collagen fibrils. That fibril diameter distribution in the lumican-null sclera was comparable to that in the wild type, but severely disrupted in the double null, suggests a role for lumican that is crucial in the absence of fibromodulin. The eyes of Lum(-/-)Fmod(-/-) mice show certain features of high myopia: increased axial length, thin sclera, and retinal detachment. Mutations or altered expression of these proteoglycans may contribute to myopia in humans.

A variety of factors, including admixture among multiple lineages, multiple modes of dispersal, and plasticity in reproductive strategy promote the invasion success of Phragmites a. australis. Wetland managers in the St. Lawrence River/Great Lakes region should focus monitoring efforts on the shores of conservation lands to prevent the establishment of propagules from novel lineages.

Fungi Pore size Cell wall void volume Wood decay Lignin Cellulose Hemicellulose Simultaneous rot Phancrochucte chrysosporium «Eunls. SummaryThe purpose of this study was to examine changes in cell wall void (pore) volume and pore sixe distribution in swcctgum wood during decay by a white-rot fungus, Phanerochaete clirysosporium Burds. Results of the study may provide quantitative answers to questions regarding the accessibility of degradative proteins to their respective substrates within the cell wall. Swectgum (LiquUkimbur styrucifluu L.) wood blocks were decayed by Phunerochtiett: chrysosporium Burds. in soil-block cultures. Lignin, cellulose and licmiccllulose were removed at approximately equal rates with progression of decay. Decay was terminated at various weight losses, and the pore volumes available to probes of various molecular weight and diameter were determined by the solute exclusion technique. The cell wall void volume in sound sweetgum wood was 0.35 ml «g*" 1 and the maximum pore diameter, 2 nm (20 A). In white-rot decayed wood, cell wall void volume increased to 0.6 ml -g ' at 40% weight loss, and maximum pore diameter increased to more than 5 nm (50 A). Most of the cell wall void volume increase resulted from the creation of pores of 2 to 5 nm (20 to 50 A) diameter. Assuming a model in which the cell wall is built of microfibrils laterally associated to form lamellae, we conclude that ligninolytic enzymes are expected to penetrate only a small fraction of new cell wall void volume, even after extensive decay, whereas small enzymes of 2 to 3 nm (20 to 30Ä) may gain access to considerable new cell void volume.

Hybridization, both within and between taxa, can be an important evolutionary stimulus for bioinvasions. Novel intra-taxon hybridizations may arise either between formerly allopatric introduced lineages, or between native and introduced lineages.