Polycomplexes – potential for bioseparation

This review discusses the properties of complexes formed by proteins with polyelectrolytes (PPC) and two polyelectrolyte molecules of opposite charge (PEC). The most highly charged polymers with ionic groups in each monomer unit are considered in this paper. There are all reasons to regard PEC as macromolecular compounds produced as a result of equilibrium reactions with inherent permanent exchange of polyions in water-salt solutions. They combine two properties that might appear at first sight to be mutually exclusive, i.e. rather high stability and lability. Introduction of bioaffinity ligands endows PEC with the recognition capacity sufficient for the purposes of bioseparation and bioanalysis. Antibody-PEC conjugates were successfully used in the immunoassay combining the advantages of both homogeneous and heterogeneous assays and for modeling of chaperone action. The unique properties of polyelectrolyte complexes in combination with bioaffinity ligands makes them promising for the development of highly efficient means of protein isolation, new immunoassay procedures and creation of reversibly soluble biocatalysts. This revised version was published online in July 2006 with corrections to the Cover Date.     

Are patients with potential celiac disease really potential? The answer of metabonomics

Celiac disease (CD) is an autoimmune disorder caused by a permanent sensitivity to gluten in genetically susceptible individuals. Accurate diagnosis of CD at an early stage and its treatment with a gluten-free diet (GFD) are important for optimum treatment and prognosis. Recently, by employing a noninvasive metabonomic approach, we have shown that CD has a well-defined metabonomic signature. Here we address potential CD patients, defined as subjects who do not have, and have never had, a jejunal biopsy consistent with clear CD, and yet have immunological abnormalities similar to those found in celiac patients. Sixty-one overt CD patients at diagnosis, 29 patients with potential CD, and 51 control subjects were examined by (1)H NMR of their serum and urine: out of 29 potential CD patients, 24 were classified as CD and 5 as control subjects. Potential CD largely shares the metabonomic signature of overt CD. Most metabolites found to be significantly different between control and CD subjects were also altered in potential CD. Our results demonstrate that metabolic alterations may precede the development of small intestinal villous atrophy and provide a further rationale for early institution of GFD in patients with potential CD, as recently suggested by prospective clinical studies.     

Tricin—a potential multifunctional nutraceutical

This review throws light on the natural occurrence and distribution of tricin (5,7,4′-trihydroxy-3′,5′-dimethoxyflavone) and its conjugated forms, as more common natural plant constituents than previously known. It examines the current literature dealing with its biosynthesis, regulation, biological significance, pharmacological effects, and potential role as a chemopreventive and anticancer agent. Because of its common occurrence in cereal grain plants and the wide spectrum of its health promoting effects, a metabolic engineering strategy is proposed to produce tricin in sufficient amounts for further experimentation, and increase its accumulation in wheat grain endosperm as a nutraceutical.     

Does competition stress decrease allelopathic potential?

In natural communities, plants compete in different ways, among them chemical interactions in the form of allelopathy. Whereas the effects of abiotic stresses (temperature, light, nutrients, etc.) on the production of allelochemicals are well known, only few studies deal with the impact of the stress induced by competition. When they do so, these studies are done under experimental conditions. The aim of this study is to evaluate the effect of intra-specific competition on the production of allelochemicals and biomass of Pinus halepensis Mill. in a natural forest using three levels of density. Phenolics and aliphatic acids were extracted from pine needles, analysed and quantified by GC-MS. Trunks, branches, needles and necromass were measured. We observed an increase in allelochemical content at low or medium level of competition and a decrease at high competition level. Moreover trees in competition allocate proportionally more biomass to the trunk and less to foliage and branches. This study provides evidence of substantial changes in allocation between the primary and the secondary metabolism.     

Streaming potential—a general affinity sensor

Electrokinetic phenomena, such as streaming potential or streaming current, have so far been used for studies of unspecific adsorption of ionic compounds on various materials. This paper shows that streaming potential measurements can also be used for studies of biospecific interactions.Several different interactions were studied, e.g. lectin-carbohydrate, IgG-Protein A. Regardless of the type of interaction an increasing change in streaming potential was obtained with increasing concentration of the interacting molecule. The authors also observed a correlation between streaming potential and affinity constants for carbohydrate-induced desorption of Concanavalin A from partially hydrolyzed Sephadex G50. In conclusion, it is shown that streaming potential measurements can be used to study molecular interactions, and to determine concentrations and relative binding constants of interacting molecules.     

A physical model of nerve axon—I. Ionic distribution,potential profile,and resting potential

A theory which is based on a set of assumptions different from those of the sodium theory is developed. Here the mobile ions are considered to be distributed at Donnan equilibrium and the axoplasm is regarded as an analog of a cation-exchanger. Following the spirit of the Debye-Hückel theory, some important features of the ionic distribution and electrical potential of the nerve fiber have been calculated. The results appear to be in better agreement with the experimental observations than the Goldman-Hodgkin-Katz equation. A summary of this work has been reported in the 1974 March meeting of the American Physical Society and the 1976 annual meeting of the Biophysical Society.     

Microfungal strains—potential lipid producers for biodiesel

The application potential of microfungal strains (Cadophora malorum, Mucor circinelloides, Trichoderma viride, nonsporulating culture Mycelia sterilia) as promising lipid producers is investigated. The C. malorum strain is found to be optimal for oil sludge recycling into biofuel. Its palmitic acid content is 52.9%, and it ensures a cetane number of the obtained biodiesel. The ability of the C. malorum strain to degrade n-alkanes and polyaromatic hydrocarbons allows the effective bioremediation of oil sludge to be performed.     

Motor unit action potential field — Modelling results

The theoretical field of a motor unit (MU) action potential (MUP) was considered. It has been proved that in normal muscles the shape of a smooth threephasic MUP curve is determined mostly by the spatial distribution of MU muscle fibres. Phenomena called time dispersion are of prime importance in pathology, where they complicate normal threephasic MUP.Amplitudes and time parameters of model three-phasic MUP were analyzed as a function of the radial distance R from the geometrical centre of the motor unit territory (MUT) and approximated by mathematical expressions. It appeared that analysis of radial variability of MUP curve allows conclusions to be made about the MUT size and the spatial distribution of MU muscle fibres. These anatomical features of a MU are often changed in pathological muscles, thus the proposed methods of their evaluation could be helpful in diagnosis of neuromuscular diseases.     

How local is the local field potential?

Local field potentials (LFPs) are of growing importance in neurophysiological investigations. LFPs supplement action potential recordings by indexing activity relevant to EEG, magnetoencephalographic, and hemodynamic (fMRI) signals. Recent reports suggest that LFPs reflect activity within very small domains of several hundred micrometers. We examined this conclusion by comparing LFP, current source density (CSD), and multiunit activity (MUA) signals in macaque auditory cortex. Estimated by frequency tuning bandwidths, these signals' "listening areas" differ systematically with an order of MUA?< CSD?< LFP. Computational analyses confirm that observed LFPs receive local contributions. Direct measurements indicate passive spread of LFPs to sites more than a centimeter from their origins. These findings appear to be independent of the frequency content of the LFP. Our results challenge the idea that LFP recordings typically integrate over extremely circumscribed local domains. Rather, LFPs appear as a mixture of local potentials with "volume conducted" potentials from distant sites.     

α-l-Arabinofuranosidases: the potential applications in biotechnology

Recently, alpha-L-arabinofuranosidases (EC3.2.1.55) have received increased attention primarily due to their role in the degradation of lignocelluloses as well as their positive effect on the activity of other enzymes acting on lignocelluloses. As a result, these enzymes are used in many biotechnological applications including wine industry, clarification of fruit juices, digestion enhancement of animal feedstuffs and as a natural improver for bread. Moreover, these enzymes could be used to improve existing technologies and to develop new technologies. The production, mechanisms of action, classification, synergistic role, biochemical properties, substrate specificities, molecular biology and biotechnological applications of these enzymes have been reviewed in this article.     

KChIPI： a potential modulator to GABAergic system

Compelling evidences from transgenic mice, immunoprecipitation data, gene expression analysis, and functional heterologous expression studies supported the role of Kv channel interacting proteins （KChIPs） as modulators of Kv4 （Shal） channels underlying the cardiac transient outward current and neuronal A-type current. Till now, there are four members （KChIP1-4） identified in this family. KChIP1 is expressed predominantly in brain, with relative abundance in Purkinje cells of cerebellum, the reticular thalamic nuclei, the medial habenular nuclei, the hippocampus, and striaturn. Our results from in situ hybridization and immunostaining assay revealed that KChIP1 was expressed in a subpopulation of parvalbumin-positive neurons suggesting its functional relationship with the GABAergic inhibitory neurons. Moreover, results obtained from KChIP1-deficient mice showed that KChIP1 mutation did not impair survival or alter the overall brain architecture, arguing against its essential function in brain development. However, the mice bearing KChIP1 deletion showed increased susceptibility to anti-GABAergic convulsive drug pentylenetetrazole-induced seizure, indicating that KChIP1 might play pivotal roles in the GABAergic inhibitory system.     

Is the clinical lipidomics a potential goldmine?

Clinical lipidomics is a new extension of lipidomics to study lipid profiles, pathways, and networks by characterizing and quantifying the complete lipid molecules in cells, biopsy, or body fluids of patients. It undoubtfully has more values if lipidomics can be integrated with the data of clinical proteomic, genomic, and phenomic profiles. A number of challenges, e.g., instability, specificity, and sensitivity, in lipidomics have to be faced and overcome before clinical application. The association of lipidomics data with gene expression and sequencing of lipid-specific proteins/enzymes should be furthermore clarified. Therefore, clinical lipidomics is expected to be more stable during handling, sensitive in response to changes, specific for diseases, efficient in data analyses, and standardized in measurements, in order to meet clinical needs. Clinical lipidomics will become a more important approach in clinical applications and will be the part of “natural” measures for early diagnosis and progress of disease. Thus, clinical lipidomics will be one of the most powerful approaches for disease-specific diagnosis and therapy, once the mystery of lipidomic profiles and metabolic enzymes is deciphered.     

Pollution effects on fisheries — potential management activities

Management of ocean pollution must be based on the best available scientific information, with adequate consideration of economic, social, and political realities. Unfortunately, the best available scientific information about pollution effects on fisheries is often fragmentary, and often conjectural; therefore a primary concern of management should be a critical review and assessment of available factual information about effects of pollutants on fish and shellfish stocks. A major problem in any such review and assessment is the separation of pollutant effects from the effects of all the other environmental factors that influence survival and well-being of marine animals. Data from long-term monitoring of resource abundance, and from monitoring of all determinant environmental variables, will be required for analyses that lead to resolution of the problem. Information must also be acquired about fluxes of contaminants through resource-related ecosystems, and about contaminant effects on resource species as demonstrated in field and laboratory experiments. Other possible management activities include: (1) encouragement of continued efforts to document clearly the localized and general effects of pollution on living resources; (2) continued pressure to identify and use reliable biological indicators of environmental degradation (indicators of choice at present are: unusually high levels of genetic and other anomalies in the earliest life history stages; presence of pollution-associated disease signs, particularly fin erosion and ulcers, in fish; and biochemical/physiological changes); and (3) major efforts to reduce inputs of pollutants clearly demonstrated to be harmful to living resources, from point sources as well as ocean dumping. Such pollution management activities, based on continuous efforts in stock assessment, environmental assessment, and experimental studies, can help to insure that rational decisions will be made about uses and abuses of coastal/estuarine waters.     

Glutathione S-transferases - potential components of anti-schistosome vaccines?

Graham Mitchell discusses how work in his and other laboratories has suggested that glutathione S-transferases may be potential candidate antigens for use in multicomponent anti-Schistosoma vaccines.     

Morse potential in DNA molecule – An experiment proposal

We rely on the helicoidal Peyrard-Bishop model for DNA dynamics. Interaction between nucleotides at a same site belonging to different strands is modelled by a Morse potential energy. This potential depends on two parameters that are different for AT and CG pairs, which is a possible source for inhomogeneity. It was shown recently (Zdravkovic and Sataric 2011) that certain values of these parameters bring about a negligible influence of inhomogeneity on the solitonic dynamics. We propose an experiment that should be carried out in order to determine the values of both of these parameters.