Tube-shaped nanostructures (nanotubes) have a number of attributes that make them potentially useful for biomedical applications such as drug delivery/detoxification and enzyme immobilization. Template synthesis provides a route for preparing monodisperse nanotubes of nearly any size and composed of nearly any material. We show here that template-synthesized silica nanotubes can be biochemically functionalized such that they act as biocatalysts and highly selective nano-phase extraction agents for bioseparations. For example, nanotubes containing an enantioselective antibody selectively extract the enantiomer of a drug molecule that binds to the antibody, relative to the enantiomer that has no specific interaction with the antibody. Nanotubes containing the enzyme glucose oxidase function as nanophase bioreactors to catalyze the oxidation of glucose.

Synthetic bio-nanotube membranes were developed and used to separate two enantiomers of a chiral drug. These membranes are based on alumina films that have cylindrical pores with monodisperse nanoscopic diameters (for example, 20 nanometers). Silica nanotubes were chemically synthesized within the pores of these films, and an antibody that selectively binds one of the enantiomers of the drug was attached to the inner walls of the silica nanotubes. These membranes selectively transport the enantiomer that specifically binds to the antibody, relative to the enantiomer that has lower affinity for the antibody. The solvent dimethyl sulfoxide was used to tune the antibody binding affinity. The enantiomeric selectivity coefficient increases as the inside diameter of the silica nanotubes decreases.

Despite the tremendous importance of secondary metabolites for humans as for the plant itself, plant secondary metabolism remains poorly characterized. Here, we present an experimental approach, based on functional genomics, to facilitate gene discovery in plant secondary metabolism. Targeted metabolite analysis was combined with cDNA-amplified fragment length polymorphism-based transcript profiling of jasmonate-elicited tobacco Bright yellow 2 cells. Transcriptome analysis suggested an extensive jasmonatemediated genetic reprogramming of metabolism, which correlated well with the observed shifts in the biosynthesis of the metabolites investigated. This method, which in addition to transcriptome data also generates gene tags, in the future might lead to the creation of novel tools for metabolic engineering of medicinal plant systems in general. P lants are capable of synthesizing an overwhelming variety of low-molecular-weight organic compounds called secondary metabolites, usually with unique and complex structures. Presently, Ϸ100,000 such compounds have been isolated from higher plants (1). Numerous plant secondary metabolites possess interesting biological activities and find applications, such as pharmaceuticals, insecticides, dyes, flavors, and fragrances. Although secondary metabolism offers attractive targets for plant breeding, the enormous biosynthetic potential of plant cells is still not being exploited. In sharp contrast, metabolism of microorganisms has been successfully engineered for increased production of pharmaceuticals or novel compounds (2, 3). Despite a few decades of research, plant secondary metabolism remains poorly characterized (4). Genetic maps of biosynthetic pathways are still far from complete, whereas knowledge on the regulation of these pathways is practically nonexistent. However, such knowledge is of crucial importance to bypass the low product yield of various secondary metabolites in plants or plant cell cultures.Functional genomics approaches are powerful tools to accelerate comprehensive investigations of cellular metabolism in specialized tissues or whole organisms (5). Yet, related to plant secondary metabolism, only a few reports have been published on such studies, which include the use of comparative quantitative trait loci mapping (6), 2D gel electrophoresis-based proteomics (7), or transcript analysis tools, such as differential display (8, 9), EST databases (10-12), and microarrays (13,14). Nevertheless, still little is known about the genetics that control quantitatively and qualitatively natural variation in secondary metabolism.Because of the lack of extensive genomic data for the vast majority of medicinal plants, it is difficult to use the commonly used microarray-based approach for transcriptome analysis in these plant systems. Such an approach requires prior development of large EST or cDNA clone collections (13,14). As such, the cDNA-amplified fragment length polymorphism (AFLP) technology (15-17) offers an attractive alternative to identify genes involved i...

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Allergies are caused by the immune reaction to commonly harmless proteins, allergens. This reaction is typified by immunoglobulin E (IgE) antibodies. We report the crystal structure of an IgE Fab fragment in complex with beta-lactoglobulin (BLG), one of the major allergens of bovine milk. The solved structure shows how two IgE/Fab molecules bind the dimeric BLG. The epitope of BLG consists of six different short fragments of the polypeptide chain, which are located especially in the beta strands, covering a flat area on the allergen surface. All six CDR (complementary-determining region) loops of the IgE Fab participate in the binding of BLG. The light chain CDR loops are responsible for the binding of the flat beta sheet region of BLG. The IgE epitope is different from common IgG epitopes that are normally located in the exposed loop regions of antigens and observed also in the two recently determined allergen-IgG complexes.

The differences in faecal bacterial population between irritable bowel syndrome (IBS) and control subjects have been reported in several studies. The aim of the present study was to compare the predominant and clostridial faecal microbiota of IBS subjects and healthy controls by applying denaturing gradient gel electrophoresis (DGGE) and a recently developed multiplexed and quantitative hybridization-based technique, transcript analysis with the aid of affinity capture (TRAC). According to the results, the studied clostridial groups (Clostridium histolyticum, Clostridium coccoides-Eubacterium rectale, Clostridium lituseburense and Clostridium leptum) represented the dominant faecal microbiota of most of the studied subjects, comprising altogether 29-87 % of the total bacteria as determined by the hybridized 16S rRNA. The C. coccoides-E. rectale group was the dominant subgroup of clostridia, contributing a mean of 43 % of the total bacteria in control subjects and 30 % (constipation type) to 50 % (diarrhoea type) in different IBS symptom category subjects. The proportion of the C. coccoides-E. rectale group was found to be significantly lower in the constipation-type IBS subjects than in the control subjects. DNA-based PCR-DGGE and RNA-based RT-PCR-DGGE analyses targeted to the predominant bacterial population showed considerable biodiversity as well as uniqueness of the microbiota in each subject, in both control and IBS subject groups. The RT-PCR-DGGE profiles of the IBS subjects further indicated higher instability of the bacterial population compared to the control subjects. The observations suggest that clostridial microbiota, in addition to the instability of the active predominant faecal bacterial population, may be involved in IBS. INTRODUCTIONThe composition of the resident intestinal microbiota varies between individuals, and the predominant population is fairly stable under normal conditions (Zoetendal et al., 1998; Harmsen et al., 2002a;Vanhoutte et al., 2004; Mättö et al., 2005). However, several factors, such as antibiotic therapy, ageing and disease, may cause disturbances in the intestinal balance. Transient disturbance of the intestinal microbiota during antibiotic therapy has been shown in several studies (Edlund & Nord, 2000; Donskey et al., 2003). Changes in the intestinal microbiota have also been suggested to occur in certain intestinal diseases and disorders, such as inflammatory bowel disease (IBD) (Seksik et al., 2003) and irritable bowel syndrome (IBS) (Madden & Hunter, 2002). IBS is an intestinal disorder that involves continuous or recurrent intestinal pain or discomfort that is relieved during defecation. In addition, IBS symptoms include bloating, altered stool frequency, form or passage, and passage of mucus (Thompson et al., 1999). The existence of abnormal colonic fermentation in IBS (King et al., 1998) and alleviation of IBS symptoms by eradication of small intestinal bacterial overgrowth by antibiotic therapy (Pimentel et al., 2000), suggest that the intestinal microbiota has...

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