Analysis of functional properties of biologically active substances using eukaryotic cell models (review)

This work presents an analysis of current data on the investigation into the functional properties of biologically active substances in model systems based on cultivated human cells. The knowledge regarding the practical application of cell cultures for the analysis of functional properties of bioactive substances is summarized, including antioxidant, immunomodulating, pro- and prebiotics, and chemoprevention properties. The most promising directions in cell culture model development for the investigation of functional properties, including three-dimensional models, are discussed.     

Functional differentiation of human brain progenitor cells

Stem cells and progenitor cells derived from the developing human brain have been shown to differentiate into neurons and astrocytes. However, few studies have examined the functional, physiological properties of these differentiated neurons and astrocytes. In this study we have used immunocytochemistry in combination with electrophysiology to examine protein machinery and functional properties of neurons and astrocytes differentiated from human brain progenitor cells (hBPCs).Our results show that serum induces mainly astrocytic phenotype cells that express GFAP and have physiological properties that are typical of astrocytes. hBPCs differentiated with BDNF and PDGF develop mainly into neurons expressing mature neuronal proteins MAP-2, synaptobrevin II and vesicular glutamate transporter I in the process, plus a small population of GFAP-positive radial cells. Based on electrophysiology of BDNF/PDGF-treated cells two classes of cell were identified. Class I cells have functional neuronal properties, including functional voltage-gated Na(+) and K(+) currents, functional AMPA receptors and the ability to generate action potentials. A smaller subpopulation of cells (Class II cells) expresses GFAP and exhibit functional properties of astrocytes, including linear current-voltage relationship and dye-coupling.     

Stability of ecosystem properties in response to above-ground functional group richness and composition

While there has been a rapidly increasing research effort focused on understanding whether and how composition and richness of species and functional groups may determine ecosystem properties, much remains unknown about how these community attributes affect the dynamic properties of ecosystems. We conducted an experiment in 540 mini‐ecosystems in glasshouse conditions, using an experimental design previously shown to be appropriate for testing for functional group richness and composition effects in ecosystems. Artificial communities representing 12 different above‐ground community structures were assembled. These included treatments consisting of monoculture and two‐ and four‐species mixtures from a pool of four plant species; each plant species represented a different functional group. Additional treatments included two herbivore species, either singly or in mixture, and with or without top predators. These experimental units were then either subjected to an experimentally imposed disturbance (drought) for 40 d or left undisturbed. Community composition and drought both had important effects on plant productivity and biomass, and on several below‐ground chemical and biological properties, including those linked to the functioning of the decomposer subsystem. Many of these compositional effects were due to effects both of plant and of herbivore species. Plant functional group richness also exerted positive effects on plant biomass and productivity, but not on any of the below‐ground properties. Above‐ground composition also had important effects on the response of below‐ground properties to drought and thus influenced ecosystem stability (resistance); effects of composition on drought resistance of above‐ground plant response variables and soil chemical properties were weaker and less consistent. Despite the positive effects of plant functional group richness on some ecosystem properties, there was no effect of richness on the resistance of any of the ecosystem properties we considered. Although herbivores had detectable effects on the resistance of some ecosystem properties, there were no effects of the mixed herbivore species treatment on resistance relative to the single species herbivore treatments. Increasing above‐ground food chain length from zero to three trophic levels did not have any consistent effect on the stability of ecosystem properties. There was no evidence of either above‐ground composition or functional group richness affecting the recovery rate of ecosystem properties from drought and hence ecosystem resilience. Our data collectively point to the role of composition (identity of functional group), but not functional group richness, in determining the stability (resistance to disturbance) of ecosystem properties, and indicates that the nature of the above‐ground community can be an important determinant of the consistency of delivery of ecosystem services.     

Isolation of a Spore Germination Inhibitor from a Cellular Slime Mold Dictyostelium discoideum

The functional properties of gluten obtained by treating with chymotrypsin at alkali pH were investigated. The gluten was treated by chymotrypsin at pH 10.0 and 20°C, and was found to be deamidated to a state that was scarcely subject to proteolysis by chymotrypsin. The degree of deamidation of the gluten reached about 25% by this treatment for 2 hr. The functional properties of the gluten thus obtained were investigated in regard to deamidation. The enzymatically deamidated gluten greatly improved such functional properties as solubility and emulsifying ability. In particular, the solubility of the treated gluten was remarkably high in the pH range of 5 to 8, in which native gluten is insoluble. It was apparent that the improvement in functional properties of gluten was mainly due to the deamidation induced by treating with chymotrypsin at pH 10.0 and 20°C.     

Identification of a heteromeric interaction that influences the rectification,gating, and pH sensitivity of Kir4.1/Kir5.1 potassium channels

Heteromultimerization between different potassium channel subunits can generate channels with novel functional properties and thus contributes to the rich functional diversity of this gene family. The inwardly rectifying potassium channel subunit Kir5.1 exhibits highly selective heteromultimerization with Kir4.1 to generate heteromeric Kir4.1/Kir5.1 channels with unique rectification and kinetic properties. These novel channels are also inhibited by intracellular pH within the physiological range and are thought to play a key role in linking K+ and H+ homeostasis by the kidney. However, the mechanisms that control heteromeric K+ channel assembly and the structural elements that generate their unique functional properties are poorly understood. In this study we identify residues at an intersubunit interface between the cytoplasmic domains of Kir5.1 and Kir4.1 that influence the novel rectification and gating properties of heteromeric Kir4.1/Kir5.1 channels and that also contribute to their pH sensitivity. Furthermore, this interaction presents a structural mechanism for the functional coupling of these properties and explains how specific heteromeric interactions can contribute to the novel functional properties observed in heteromeric Kir channels. The highly conserved nature of this structural association between Kir subunits also has implications for understanding the general mechanisms of Kir channel gating and their regulation by intracellular pH.     

Preparation and UV-protective properties of functional cellulose fabrics based on reactive azobenzene Schiff base derivative

Azobenzene Schiff base possesses excellent photochromic or thermochromic properties based on intermolecular proton transfer or cis-trans isomerization. The azobenzene Schiff base containing two reactive groups, N, N-bis{p-[(2′-sulphatoethyl)sulphonyl phenylazo] salicylidene}-1,2-ethylenediamine (BSPEA), was applied to modify cellulose materials. The functional cellulose fabrics containing azobenzene Schiff base groups were prepared. The chemical and morphological structures of functional cellulose fabrics were characterized by element analysis, FT-IR spectrum, and scanning electron microscopy (SEM). The UV-protection properties of the fabrics were investigated by the ultraviolet transmittance spectra and ultraviolet protection factor (UPF). The results show that the functional cellulose fabrics had excellent UV-protection properties with higher UPF value (UPF value reached 31.7) and lower ultraviolet transmittance (less than 5%). The modified cellulose fabrics had not significant influence on the physical properties. The functional cellulose fabrics based on reactive azobenzene Schiff base would have potential application in textile and functional materials.     

Force-length properties and functional demands of cat gastrocnemius, soleus and plantaris muscles.

The purpose of this study was to measure isometric force-length properties of cat soleus, gastrocnemius and plantaris muscle-tendon units, and to relate these properties to the functional demands of these muscles during everyday locomotor activities. Isometric force-length properties were determined using an in situ preparation, where forces were measured using buckle-type tendon transducers, and muscle-tendon unit lengths were quantified through ankle and knee joint configurations. Functional demands of the muscles were assessed using direct muscle force measurements in freely moving animals. Force-length properties and functional demands were determined for soleus, gastrocnemius and plantaris muscles simultaneously in each animal. The results suggest that isometric force-length properties of cat soleus, gastrocnemius and plantaris muscles, as well as the region of the force-length relation that is used during everyday locomotor tasks, match the functional demands.     

Letter: Equilibrium and kinetic studies of hemoglobin I: a functionally silent amino acid substitution at an invariant residue;

Hemoglobin I is an uncommon hemoglobin variant in which the lysine residue at position 16 of the a chain has been replaced by glutamic acid. Lysine is the invariant residue in all myoglobin and hemoglobin subunits that have been sequenced, with the exception of the hemoglobin of the lamprey. Replacement of invariant residues is generally reflected in altered functional properties of the hemoglobin molecule and such invariance may be indicative of a unique functional role. However, a study of the oxygen equilibrium and kinetic properties of hemoglobin I showed the functional properties of this hemoglobin to be indistinguishable from those of normal adult hemoglobin.     

放牧强度对高寒草甸土壤理化性状和植物功能群的影响

为明晰放牧强度对植物功能群落的物种分布特征和土壤理化性状的影响。在青藏高原东北缘高寒草甸设置6块放牧强度样地开展试验。采用多元排序和方差分解等方法,分析放牧强度作用下植物功能群落物种分布与土壤物理结构和化学养分因子的定量关系。结果表明:(1)随放牧强度增加,禾本科、莎草科和多年生杂类草植物群落的物种丰富度、盖度和实际重要值均显著降低,而一年生杂类草无显著变化。(2)对于土壤化学养分,不同放牧强度区,土壤速效钾、全氮和有机质含量均随土层深度的增加而降低,土壤速效磷在不同放牧强度区变化规律不一致。随放牧强度增加,土壤速效钾和全氮含量增加,而土壤速效磷和有机质含量无明显变化。(3)对于土壤物理性状,不同放牧强度区,随土层深度增加,土壤紧实度和容重均增加,而土壤含水量和通气孔隙度均降低。随放牧强度增加,0—30 cm各土层深度的土壤紧实度和容重均增加,土壤含水量和通气孔隙度均降低。(4)以功能群为基本单元对植物群落进行方差分解得出,土壤物理性状可单独解释群落功能群分布总方差的58.10%。(5)基于物种尺度对不同功能群落与环境因子进行定量研究表明,土壤紧实度是决定每种功能群物种分布格局的最主要因子。禾本科、莎草科和多年生草本植物均受土壤物理性状的显著影响,贡献率分别为26.3%、31.0%和16.5%。而一年生草本植物不受土壤物理和化学性状的显著影响。综上所述,放牧强度对土壤化学性状的影响具有不确定性,而对土壤物理性状和群落特征的影响具有确定性。土壤物理结构性状主导了高寒草甸植物功能群落的物种分布格局。     

宁夏荒漠草原蒙古冰草功能性状和根际效应对土壤性状的响应

植物功能性状组合的权衡是植物适应土壤环境的重要机制,它也通过对根际效应的调控进而影响着根际过程和生态系统功能。以位于宁夏盐池县的典型荒漠草原为研究区域,通过对灰钙土、黑垆土和风沙土中蒙古冰草功能性状和根际效应的对比分析,探究不同土壤对蒙古冰草功能性状和根际效应的影响以及它们之间的关系。结果表明：(1)不同土壤中蒙古冰草根际和非根际土壤理化性质存在显著差异,根际土壤理化性质的变化与非根际土壤性质有关。(2)不同土壤中的根际效应大小存在差异,不同因子的根际效应大小因土壤而异,总体表现为风沙土最大,灰钙土最小;土壤理化性质是影响蒙古冰草根际效应的主要因素,可解释根际效应变异的69.5%。(3)土壤理化性质与蒙古冰草功能性状密切相关,其对根长和根冠比的影响最大;蒙古冰草功能性状与根际效应大小密切相关,根长和根冠比是影响根际效应的主要因子。研究表明蒙古冰草通过根际效应改善了土壤性质,进而提高土壤质量,这种作用受土壤理化性质和植物功能性状等因子的共同影响。     

Functional and molecular distinction between recombinant rat GABAA receptor subtypes by Zn2+.

gamma-Aminobutyric acid receptor (GABAAR) channels in different neurons display heterogeneous functional properties. Molecular cloning revealed a large number of GABAAR subunits that assemble into GABAAR subtypes with different functional properties, suggesting that the subunit combination determines the functional properties of the receptor. In this study, the subunit composition of GABAARs is related to a functional distinction between Zn2(+)-sensitive and Zn2(+)-insensitive receptor subtypes. GABAARs reconstituted in transiently transfected fibroblasts from combinations of cDNAs encoding alpha and beta subunits are potently blocked by Zn2+. The presence of a gamma subunit in any combination with the other subunits leads to the formation of GABAARs that are almost insensitive to Zn2+. These data provide a structural correlate to the functional heterogeneity of the action of Zn2+ on GABAARs in native membranes and show that Zn2+ insensitivity of GABA-activated currents indicates the presence of a gamma-subunit in the assembled GABAAR channel.     

Topological Organization of Functional Brain Networks in Healthy Children: Differences in Relation to Age,Sex, and Intelligence

Recent studies have demonstrated developmental changes of functional brain networks derived from functional connectivity using graph theoretical analysis, which has been rapidly translated to studies of brain network organization. However, little is known about sex- and IQ-related differences in the topological organization of functional brain networks during development. In this study, resting-state fMRI (rs-fMRI) was used to map the functional brain networks in 51 healthy children. We then investigated the effects of age, sex, and IQ on economic small-world properties and regional nodal properties of the functional brain networks. At a global level of whole networks, we found significant age-related increases in the small-worldness and local efficiency, significant higher values of the global efficiency in boys compared with girls, and no significant IQ-related difference. Age-related increases in the regional nodal properties were found predominately in the frontal brain regions, whereas the parietal, temporal, and occipital brain regions showed age-related decreases. Significant sex-related differences in the regional nodal properties were found in various brain regions, primarily related to the default mode, language, and vision systems. Positive correlations between IQ and the regional nodal properties were found in several brain regions related to the attention system, whereas negative correlations were found in various brain regions primarily involved in the default mode, emotion, and language systems. Together, our findings of the network topology of the functional brain networks in healthy children and its relationship with age, sex, and IQ bring new insights into the understanding of brain maturation and cognitive development during childhood and adolescence.     

Functional finishing of health care cotton for enhanced efficiency of antibacterial activity by chitosan and herbal nanocomposites

To enhance the efficiency of biological, chemical and physical properties like antibacterial activity, wash durability, air-permeability and biocompatibility of cotton fabric finished with chitosan and herbal nanocomposites. Extracts of Cassia angustifolia and Tamarindus indica with chitosan solution was bulk finished on 40s cotton fabrics. To increase the functional properties, chitosan and herbal extract nanocomposites were finished on to another set of fabrics (nanocomposite finishing). Different functional properties were carried out for both the sets of fabrics and comparatively analyzed. Antibacterial activity, physical properties and biocompatible properties of the finished fabric were determined. Antibacterial activity of nanocomposite finished fabrics showed inhibitory zones of 33 mm for E. coli and 31.6 mm for S. aureus. Nanocomposite finished fabrics showed good durable properties and physical properties than bulk finished fabrics. The study concludes that, nanocomposites could provide better functional properties than the bulk finished fabrics. The nano sized particles in the composites was considered significant for its functional applications in hospital based fabrics to prevent the transmission of nosocomial infections.     

Functional network organization of the human brain

Real-world complex systems may be mathematically modeled as graphs, revealing properties of the system. Here we study graphs of functional brain organization in healthy adults using resting state functional connectivity MRI. We propose two novel brain-wide graphs, one of 264 putative functional areas, the other a modification of voxelwise networks that eliminates potentially artificial short-distance relationships. These graphs contain many subgraphs in good agreement with known functional brain systems. Other subgraphs lack established functional identities; we suggest possible functional characteristics for these subgraphs. Further, graph measures of the areal network indicate that the default mode subgraph shares network properties with sensory and motor subgraphs: it is internally integrated but isolated from other subgraphs, much like a "processing" system. The modified voxelwise graph also reveals spatial motifs in the patterning of systems across the cortex.     

Particle size distribution of rice flour affecting the starch enzymatic hydrolysis and hydration properties

Rice flour is becoming very attractive as raw material, but there is lack of information about the influence of particle size on its functional properties and starch digestibility. This study evaluates the degree of dependence of the rice flour functional properties, mainly derived from starch behavior, with the particle size distribution. Hydration properties of flours and gels and starch enzymatic hydrolysis of individual fractions were assessed. Particle size heterogeneity on rice flour significantly affected functional properties and starch features, at room temperature and also after gelatinization; and the extent of that effect was grain type dependent. Particle size heterogeneity on rice flour induces different pattern in starch enzymatic hydrolysis, with the long grain having slower hydrolysis as indicated the rate constant (k). No correlation between starch digestibility and hydration properties or the protein content was observed. It seems that in intact granules interactions with other grain components must be taken into account. Overall, particle size fractionation of rice flour might be advisable for selecting specific physico-chemical properties.     

Biological activities and potential cosmeceutical applications of bioactive components from brown seaweeds: a review

Seaweeds are the primary producers of all aquatic ecosystems. Chemical constituents isolated from diverse classes of seaweeds exert a wide range of nutritional, functional and biological activities. Unique metabolites of seaweeds possess specific biological properties that make them potential ingredients of many industrial applications such as functional foods, pharmaceuticals and cosmeceuticals. Cosmeceuticals of natural origin are becoming more popular than synthetic cosmetics. Hence, the investigation of new seaweeds derived functional components, a different source of natural products, has proven to be a promising area of cosmeceutical studies. Brown seaweeds also produce a range of active components including unique secondary metabolites such as phlorotannins and many of which have specific biological activities that give possibilities for their economic utilization. Brown seaweeds derived active compounds have been shown various functional properties including, antioxidant, antiwrinkling, whitening, antiinflammatory and antiallergy. It is well-known that these kind of biological effects are closely associated with cosmeceutical preparations. This communication reviews the current knowledge on brown seaweeds derived metabolites with various biological activities and the potential use as cosmeceutical ingredients. It is hoped that the reviewed literature on multifunctional properties of brown seaweeds will improve access to the seaweed based natural products specially the ability to incorporate these functional properties in cosmeceutical applications.     

Discharge properties of motoneurones: how are they matched to the properties and use of their muscle units?

A general survey is given of old as well as more recent findings concerning matches between electrophysiological properties of motoneurones and contractile properties of their muscle fibres. Mechanisms for creating and maintaining such matches are discussed. It is pointed out that it is not sufficient to describe the variation of functional motoneurone characteristics simply in terms of 'fast' or 'slow': all properties seem continuously graded and there is cytochemical evidence for several, seemingly independent parameters of functional specialisation.     

Task-Related Changes in Functional Properties of the Human Brain Network Underlying Attentional Control

Previous studies have demonstrated task-related changes in brain activation and inter-regional connectivity but the temporal dynamics of functional properties of the brain during task execution is still unclear. In the present study, we investigated task-related changes in functional properties of the human brain network by applying graph-theoretical analysis to magnetoencephalography (MEG). Subjects performed a cue-target attention task in which a visual cue informed them of the direction of focus for incoming auditory or tactile target stimuli, but not the sensory modality. We analyzed the MEG signal in the cue-target interval to examine network properties during attentional control. Cluster-based non-parametric permutation tests with the Monte-Carlo method showed that in the cue-target interval, beta activity was desynchronized in the sensori-motor region including premotor and posterior parietal regions in the hemisphere contralateral to the attended side. Graph-theoretical analysis revealed that, in beta frequency, global hubs were found around the sensori-motor and prefrontal regions, and functional segregation over the entire network was decreased during attentional control compared to the baseline. Thus, network measures revealed task-related temporal changes in functional properties of the human brain network, leading to the understanding of how the brain dynamically responds to task execution as a network.     

Transformation of common wheat (Triticum aestivum L.) with avenin-like b gene improves flour mixing properties

Avenin-like b proteins may contribute to the viscoelastic properties of wheat dough via inter-chain disulphide bonds, due to their rich cysteine residues. In order to clarify the effect of the avenin-like b proteins on the functional properties of wheat flour, the functional and biochemical properties of wheat flour were analyzed in three transgenic wheat lines overexpressing the avenin-like b gene using the sodium dodecyl sulfate sedimentation (SDSS) test, Mixograph and size exclusion-high performance liquid chromatography (SE-HPLC) analysis. The results of the SDSS test and Mixograph analysis demonstrated that the overexpression of avenin-like b proteins in transgenic lines led to significantly increased SDSS volume and improved flour mixing properties. The results of SE-HPLC analysis of the gluten proteins in wheat flour demonstrated that the improvement in transgenic line flour properties was associated with the increased proportion of large polymeric proteins due to the incorporation of overexpressed avenin-like b proteins into the glutenin polymers. These results could help to understand the influence and mechanism of avenin-like b proteins on the functional properties of wheat flour.     

Fluorescence-Based High-Throughput Functional Profiling of Ligand-Gated Ion Channels at the Level of Single Cells

Ion channels are involved in many physiological processes and are attractive targets for therapeutic intervention. Their functional properties vary according to their subunit composition, which in turn varies in a developmental and tissue-specific manner and as a consequence of pathophysiological events. Understanding this diversity requires functional analysis of ion channel properties in large numbers of individual cells. Functional characterisation of ligand-gated channels involves quantitating agonist and drug dose-response relationships using electrophysiological or fluorescence-based techniques. Electrophysiology is limited by low throughput and high-throughput fluorescence-based functional evaluation generally does not enable the characterization of the functional properties of each individual cell. Here we describe a fluorescence-based assay that characterizes functional channel properties at single cell resolution in high throughput mode. It is based on progressive receptor activation and iterative fluorescence imaging and delivers >100 dose-responses in a single well of a 384-well plate, using α1-3 homomeric and αβ heteromeric glycine receptor (GlyR) chloride channels as a model system. We applied this assay with transiently transfected HEK293 cells co-expressing halide-sensitive yellow fluorescent protein and different GlyR subunit combinations. Glycine EC₅₀ values of different GlyR isoforms were highly correlated with published electrophysiological data and confirm previously reported pharmacological profiles for the GlyR inhibitors, picrotoxin, strychnine and lindane. We show that inter and intra well variability is low and that clustering of functional phenotypes permits identification of drugs with subunit-specific pharmacological profiles. As this method dramatically improves the efficiency with which ion channel populations can be characterized in the context of cellular heterogeneity, it should facilitate systems-level analysis of ion channel properties in health and disease and the discovery of therapeutics to reverse pathological alterations.