Search

Multicellular algae are the core topic for understanding the early life evolution on Earth. The timing of origin and cellular differentiation of multicellular algae, however, remains poorly constrained. The Palaeoproterozoic to early Mesoproterozoic is a critical period during which multicellular algae began to occur and evolve in marine environments. This paper reports well‐preserved multicellular fossils from shales of the Chuanlinggou Formation (c. 1.64 Ga) in North China, with emphasis on their holdfast and putative cellular structures. These macroalgal fossils are reasonably diversified and include Chuaria circularis, Tawuia sinensis, Tawuia robusta, Glossophyton ovalis, Glossophyton sp., Tuanshanzia sp. and Changchengia sp.; mainly preserved as carbonaceous compressions, with a few sideritized forms. Field emission scanning electron microscope (FESEM) observation revealed multicellular structures in Chuaria, confirming its biological attributes of a multicellular eukaryote and providing direct evidence that multicellular algae had already originated by the terminal Palaeoproterozoic, earlier than previously speculated. Tuanshanzia sp. and Changchengia sp. developed with a bare rhizome holdfast, suggesting that they had a benthic sessile lifestyle in their late Palaeoproterozoic oceanic habitat. [ABSTRACT FROM AUTHOR]

A method has been designed for patterning supported phospholipid bilayers (SLBs) on planar substrates and inside microfluidic channels. To do this, bovine serum albumin (BSA) monolayers were formed via adsorption at the liquid/solid interface. Next, this interfacial protein film was selectively patterned by using deep IN lithography. Subsequently, SLBs could be deposited in the patterned locations by vesicle fusion. By cycling through this process several times, spatially addressed bilayer arrays could be formed with intervening protein molecules serving as two-dimensional corrals. By employing this method, phospholipid bilayers containing various concentrations of ganglioside GM1 were addressed along the length of individual microfluidic channels. Therefore, the binding of GM 1 with pentameric cholera toxin B (CTB) subunits could be probed. A seven-channel microfluidic device was fabricated for this purpose. Each channel was simultaneously patterned with four chemically distinct SLBs containing 0, 0.2, 0.5, and 2.0 mol % GM1, respectively. Varying concentrations of CrB were then introduced into each of the channels. With the use of total internal reflection fluorescence microscopy, it was possible to simultaneously abstract multiple equilibrium dissociation constants as a function of ligand density for the CTB-GM1 system in a single shot.

Investigations of ligand-receptor binding bivalent antibodies and membrane-bound ligands are presented. The purpose of the investigations is to explore binding as a function of Hapten density in a two-dimensionally fluid environment.

Research has been conducted on the methods for combinatorial and array-based data obtaining. The microfluidics used in generating a linear temperature gradient across various samples which can be read off as a position function are discussed.

Herein we report the fabrication, characterization, and use of total analytical microsystems containing surface-immobilized enzymes. Streptavidin-conjugated alkaline phosphatase was linked to biotinylated phospholipid bilayers coated inside poly(dimethylsiloxane) microchannels and borosilicate microcapillary tubes. Rapid determination of enzyme kinetics at many different substrate concentrations was made possible by carrying out laminar flow-controlled dilution on-chip. This allowed Lineweaver--Burk analysis to be performed from a single experiment with all the data collected simultaneously. The results revealed an enzyme turnover number of 51.1 [+ or -] 3.2 [s.sup.-1] for this heterogeneous system. Furthermore, the same enzyme immobilization strategy was extended to demonstrate that multiple chemical reactions could be performed in sequence by immobilizing various enzymes in series. Specifically, the presence of glucose was detected by two coupled steps employing immobilized avidinD-conjugated glucose oxidase and streptavidin-conjugated horseradish peroxidase.

Herein we report the use of microcontact displacement ((mu)CD) to generate addressable arrays of aqueous solutions above fluid lipid bilayers by bringing a patterned PDMS mold into conformal contact with a phospholipid membrane on a solid supported substrate. Epifluorescence microscopy established that the bilayer material was displaced in regions where contact between the mold and substrate was made. Photobleaching experiments confirmed that the bilayer sectors remained individually fluid but completely separated. The microcompartments created by (mu)CD could be individually injected with aqueous solutions that remained sealed from their neighbors. This procedure was then exploited for screening a small library of aqueous-phase molecules for their ability to inhibit binding between surface-bound ligands and soluble protein receptors.

A new genus and species, Micromartinia kwangsiella gen. et sp. nov., is erected based on material from the Talung Formation (upper Changhsingian), Guangxi, South China. Based on a phylogenetic analysis, the new genus is placed in a new family, Micromartiniidae He & Weldon. The genus and family are monotypic. Minutomarginifera nomen novum is proposed to replace Eileenella Racheboeuf in Wongwanich et al., 2004. Eileenella is a homonym that was first used for an insect genus. A review of the brachiopod fauna of the Talung Formation at Dongpan demonstrates that the species are highly endemic and the fauna has a strongly generic affinity with cool-water faunas outside of South China Basin. The associated fauna and facies also indicate that the Dongpan Section was deposited in a cool-water bathyal setting in the southern part (Youjiang Sub-basin) of the South China Basin. The section was linked to the open ocean in the Late Permian. Compared with the coeval faunas of Duanshan and Shaiwa in the Youjiang Sub-basin, the Dongpan brachiopod fauna was not so strongly influenced by the faunas from the adjacent carbonate platforms, because of the deeper, cool water setting which is hostile to the typical warm-water brachiopods. [ABSTRACT FROM AUTHOR]