Progress in deciphering the information content of the ‘glycome’ – a crescendo in the closing years of the millennium

The closing years of the second millennium have been uplifting for carbohydrate biology. Optimism that oligosaccharide sequences are bearers of crucial biological information has been borne out by the constellation of efforts of carbohydrate chemists, biochemists, immunochemists, and cell- and molecular biologists. The direct involvement of specific oligosaccharide sequences in protein targeting and folding, and in mechanisms of infection, inflammation and immunity is now unquestioned. With the emergence of families of proteins with carbohydrate-binding activities, assignments of information content for defined oligosaccharide sequences will become more common, but the pinpointing and elucidation of the bioactive domains on oligosaccharides will continue to pose challenges even to the most experienced carbohydrate biologists. The neoglycolipid technology incorporates some of the key requirements for this challenge: namely the resolution of complex glycan mixtures, and ligand binding coupled with sequence determination by mass spectrometry.     

Effect of the bidistilled modified water on bovine serum albumin conformation. Fluorescent spectroscopy data

It was shown that bidistilled modified water induces a marked decrease in the intensity of intrinsic fluorescence of bovine serum albumin and increases the binding of this protein to the fluorescent probe 1.8 ANS. These effects can be interpreted as a denaturing action of bidistilled modified water on the protein and a change in its conformational state, which is probably caused by changes in the microenvironment of the protein molecule. In addition, a substantial increase in the intrinsic fluorescence of bidistilled modified water, as compared with that of distilled water, was found.     

Regulatory factors and cell populations involved in skeletal muscle regeneration

Skeletal muscle regeneration is a complex process, which is not yet completely understood. Satellite cells, the skeletal muscle stem cells, become activated after trauma, proliferate, and migrate to the site of injury. Depending on the severity of the myotrauma, activated satellite cells form new multinucleated myofibers or fuse to damaged myofibers. The specific microenvironment of the satellite cells, the niche, controls their behavior. The niche contains several components that maintain satellite cells quiescence until they are activated. In addition, a great diversity of stimulatory and inhibitory growth factors such as IGF‐1 and TGF‐β1 regulate their activity. Donor‐derived satellite cells are able to improve muscle regeneration, but their migration through the muscle tissue and across endothelial layers is limited. Less than 1% of their progeny, the myoblasts, survive the first days upon intra‐muscular injection. However, a range of other multipotent muscle‐ and non‐muscle‐derived stem cells are involved in skeletal muscle regeneration. These stem cells can occupy the satellite cell niche and show great potential for the treatment of skeletal muscle injuries and diseases. The aim of this review is to discuss the niche factors, growth factors, and other stem cells, which are involved in skeletal muscle regeneration. Knowledge about the factors regulating satellite cell activity and skeletal muscle regeneration can be used to improve the treatment of muscle injuries and diseases. J. Cell. Physiol. 224:7–16, 2010 © 2010 Wiley‐Liss, Inc.     

Multimodal interval distributions

Summary A mathematical model is presented that is supposed to describe certain types of multimodal interval distributions of neuronal discharges. Basically it consits of the selective interaction between an excitatory and an inhibitory impulse sequence. The theoretical results are compared with nerve cell interval distributions reported in the literature, and with distributions from simulation studies. A possible relationship between the properties of this model and longtailed interval distributions is indicated. Several extensions are discussed.     

A plate assay for simultaneous screening of polysaccharide- and protein-degrading micro-organisms

AIMS: To develop a plate assay for simultaneous screening of polysaccharide-degrading and protein-degrading micro-organisms. METHODS AND RESULTS: A plate assay, based on the visible solubilization of small substrate particles and the formation of haloes on Petri dishes, containing a mixture of diversely coloured insoluble polysaccharides and dye-labelled collagen as chromogenic substrates, was developed. This method was successfully applied for isolating the diverse polysaccharide- and/or protein-degrading bacteria from soil and sludge samples. Selected strains were identified using 16S rDNA partial sequencing; most of them belong to the genera Bacillus, Cellulomonas and Cellulosimicrobium. CONCLUSIONS: This novel approach provides unique and valuable information for direct primary screening when the target of selection is micro-organisms exhibiting protein-degrading activity, polysaccharide-degrading activity or a specific combination of them. SIGNIFICANCE AND IMPACT OF THE STUDY: This plate assay is convenient and easy to perform, rapid, and more adaptable for screening of a large number of samples, compared with other existing methods in the literature.     

Rap2A links intestinal cell polarity to brush border formation

The microvillus brush border at the apex of the highly polarized enterocyte allows the regulated uptake of nutrients from the intestinal lumen. Here, we identify the small G protein Rap2A as a molecular link that couples the formation of microvilli directly to the preceding cell polarization. Establishment of apicobasal polarity, which can be triggered by the kinase LKB1 in single, isolated colon cells, results in enrichment of PtdIns(4,5)P(2) at the apical membrane. The subsequent recruitment of phospholipase D1 allows polarized accumulation of phosphatidic acid, which provides a local cue for successive signalling by the guanine nucleotide exchange factor PDZGEF, the small G protein Rap2A, its effector TNIK, the kinase MST4 and, ultimately, the actin-binding protein Ezrin. Thus, epithelial cell polarization is translated directly into the acquisition of brush borders through a small G protein signalling module whose action is positioned by a cortical lipid cue.     

Patterns of DNA and chromosome variation during in vitro growth in various genotypes of potato

Patterns of variation in nuclear DNA content and chromosome number were analysed in a temporal sequence, during in vitro growth of calli and cell suspensions in two monohaploids, a dihaploid and a tetraploid of potato (Solanum tuberosum). The results showed that both polyploidization and aneuploidy occurred during the initial stages of callus induction in all the genotypes. With further growth of callus, the frequency and extent of polyploidy and aneuploidy increased. In addition, the patterns of DNA and chromosome variation in cell suspension cultures revealed continued mitotic activity and transmission of cells with higher ploidy levels and aneuploidy. The results suggest that endoreduplication as well as endomitosis are important mechanisms of polyploidization, and that chromosome lagging and non-disjunction contribute to the production of aneuploidy.The various genotypes cultured under the same in vitro growth conditions differed in genetic instability, as assessed from the rate and degree of polyploidization and aneuploidy. Monohaploids showed more rapid rate of polyploidization than the dihaploid and tetraploid potatoes. It was concluded that the differences in genetic stability were due to different ploidy levels and genetic make-up of the genotypes.