Differential expression of S100 proteins in the developing human hippocampus and temporal cortex

S100 calcium binding proteins have long been known to express in the adult nervous system, but their distribution in the developing brain, especially the human fetal brain, is largely unknown. We used an immunohistochemical method to determine the expression of three S100 proteins, namely S100A4, S100A5, and S100A13, in the human fetal hippocampus and temporal cortex from 12 to 33 weeks of gestation. At 12 weeks, S100A5 was strongly expressed in the cells and fibers of the polymorphic, pyramidal, and molecular layers of the hippocampus. Thereafter, its expression decreased with age. In the temporal cortex, S100A5 expression was detected from 12 weeks onwards, peaked at 20 to 24 weeks, and then decreased with age. The horizontal fibers of the marginal zone were immunoreactive at all stages examined. S100A13 immunoreactivity was also detected in both cells and fibers of the hippocampus at 12 weeks, became slightly stronger at 20 weeks, and then decreased with age. In the temporal cortex, S100A13 immunoreactivity was also strong in all cellular layers at 12 to 24 weeks before it declined with age from 28 weeks onwards. Among the three proteins examined, S100A4 showed the weakest expression, which was detected in the cells and fibers of the hippocampus and the temporal cortex at all stages examined. Our results have demonstrated for the first time, in the human fetal hippocampus and temporal cortex, specific spatio-temporal patterns of expression of these proteins, all of which are likely to have different roles to play during development despite their pronounced sequence homology.     

Subcellular localization of S100A11 (S100C) in LLC-PK1 renal cells: Calcium- and protein kinase c-dependent association of S100A11 with S100B and vimentin intermediate filaments

The subcellular localization of the Ca(2+)-modulated protein, S100A11, was investigated in the renal cell line LLC-PK1 by immunofluorescence and confocal laser scanning microscopy under varying experimental conditions. In control cells, S100A11 was detected on the plasma membrane, where the protein co-localized with annexin I (ANXA1) at discrete sites, and found diffusely in the cytoplasm. Elevation of the cytosolic Ca(2+) concentration by means of the Ca(2+) ionophore, ionomycin, caused a significant fraction of S100A11 to associate with vimentin intermediate filament (IF)-bound S100B, another member of the S100 protein family. Under these conditions, ANXA1 underwent a quite different kind of relocation. Translocation of S100A11 onto vimentin IF-bound S100B was also observed upon activation of protein kinase C (PKC). Under these conditions, S100A11 appeared to associate directly with vimentin IFs at cell sites displaying low or no abundance of S100B such as cell processes, and, again, S100A11 and ANXA1 underwent a different relocation. Our data suggest the possibility that the intracellular Ca(2+) level might regulate the subcellular localization of S100A11 and its interaction with definite target proteins, and that S100A11 might serve the function of modulating S100B activities. Interestingly, in spite of the known ability of S100A11 to form heterotetramers with ANXA1, the two proteins underwent a different relocation on elevation of the cytosolic Ca(2+) concentration or activation of PKC, pointing to different regulatory activities of individual proteins in renal cells.     

S100A9/S100A8: Myeloid representatives of the S100 protein family as prominent players in innate immunity

Neutrophils are rapidly recruited to sites of inflammation and are thereby at the forefront of the organism's defense against numerous attacks. As unspecific phagocytes, they belong to the so-called innate immunity. Two S100 proteins, namely S100A9 (MRP14) and S100A8 (MRP8), constitute roughly 40% of the cytosolic protein in these cells, implying by their pure abundance an important role in the effector functions of neutrophils. However, despite intense research in the past 15 years, the puzzle that may embed both molecules into the neutrophil/monocyte physiology is still incomplete. One reason might be the conformational variability the S100A9 and S100A8 molecules can adopt. They readily form hetero- and homodimeric, trimeric as well as tetrameric complexes, but they evidently do also exert specific functions as monomers. An ever-increasing body of information suggests that S100A9 plays a prominent role in leukocyte trafficking and arachidonic acid metabolism. In addition, elevated levels of S100A9 and S100A8 in body fluids of inflamed tissues strengthen the view that these molecules are important players in fighting inflammation. The aim of this review is to give an update on the current developments concerning the S100A9/S100A8 molecule in biology and medicine.     

Possible roles of extracellular matrix and cytoskeleton in leech body wall muscles

Round circomyarian fibres of leeches are peculiar helical muscles. The fibres are characterized by a lack of junctions, being separated by a thick extracellular matrix, and by scarce end-plates. Even so, the fibres grouped in units show the same degree of contraction. Biochemical, immunocytochemical and ultrastructural studies were performed in order: (a) to demonstrate the presence in the extracellular matrix of fibronectin, collagen type IV and laminin and in the cytoskeleton of desmin and α-actinin; (b) to show the possible link of extracellular matrix with the scaffold of intermediate filaments; (c) to evaluate how the extracellular matrix can play a role in the transduction of a signal during contraction–relaxation–superelongation phases.     

The XL-100S microprogrammable processor

The XL-100S is a microprogrammable device based on the Am2900 family of bit slices and designed for use in the multimaster environment of an XL System Crate. The processor conforms to the EUR 6500 CAMAC standard and can access up to 4 Mbyte of memory and 7 CAMAC branches. Processor operation, which is a sequence of predefined microcommands fetched from a 32-bit wide control store with capacity up to 64 kwords, can be initiated by any of eight external requests.The architecture of the XL-100S allows it to emulate almost any mini- or micro-computer including floating point operations. The processor can be used for: fast physical event filtering and data preprocessing, flexible apparatus control, organization of sophisticated DMA transfer modes, etc. The device with 4 kwords of control store is housed in a single width CAMAC module.     

S100B in brain damage and neurodegeneration

S100B is a calcium-binding peptide produced mainly by astrocytes that exert paracrine and autocrine effects on neurons and glia. Some knowledge has been acquired from in vitro and in vivo animal experiments to understand S100B's roles in cellular energy metabolism, cytoskeleton modification, cell proliferation, and differentiation. Also, insights have been gained regarding the interaction between S100B and the cerebral immune system, and the regulation of S100B activity through serotonergic transmission. Secreted glial S100B exerts trophic or toxic effects depending on its concentration. At nanomolar concentrations, S100B stimulates neurite outgrowth and enhances survival of neurons during development. In contrast, micromolar levels of extracellular S100B in vitro stimulate the expression of proinflammatory cytokines and induce apoptosis. In animal studies, changes in the cerebral concentration of S100B cause behavioral disturbances and cognitive deficits. In humans, increased S100B has been detected with various clinical conditions. Brain trauma and ischemia is associated with increased S100B concentrations, probably due to the destruction of astrocytes. In neurodegenerative, inflammatory and psychiatric diseases, increased S100B levels may be caused by secreted S100B or release from damaged astrocytes. This review summarizes published findings on S100B regarding human brain damage and neurodegeneration. Findings from in vitro and in vivo animal experiments relevant for human neurodegenerative diseases and brain damage are reviewed together with the results of studies on traumatic, ischemic, and inflammatory brain damage as well as neurodegenerative and psychiatric disorders. Methodological problems are discussed and perspectives for future research are outlined.     

Molecular mechanisms of S100-target protein interactions

S100 proteins have no known enzymatic activity and exert their intracellular effects via interaction with and regulation of the activity of other proteins, termed target proteins, in both a Ca(2+)-dependent and Ca(2+)-independent manner. Structural studies have identified the linker region between the two EF-hand Ca(2+) binding domains and the C-terminus as Ca(2+)-dependent target protein binding sites in several S100 family members. In fact, C-terminal aromatic residues are obligatory for interaction of S100A1 with several of its Ca(2+)-dependent target proteins. Pharmacological studies suggest the presence of additional Ca(2+)-dependent binding motifs on some family members. A minimum of seven family members interact with and regulate the activity of aldolase A in a Ca(2+)-independent manner. In the case of S100A1, Ca(2+)-independent target protein interactions utilize a binding motif distinct from the C-terminal Ca(2+)-dependent target protein binding site. Several studies suggest that ionic interactions participate in the interaction of S100 family members with Ca(2+)-independent target proteins. While some target proteins are activated by multiple family members, other target proteins exhibit family member-specific activation, i.e., they are activated by a single family member. As predicted, family member specific interactions appear to be mediated by regions that exhibit the most divergence in amino acid sequence among family members, the linker or "hinge" region and the C terminus. Further specificity in S100-target protein interactions may arise from the different biochemical/biophysical properties of the individual family members, including affinity for metal ions (Ca(2+), Zn(2+), and Cu(2+)), oligomerization properties, heterodimerization, post-translational modifications, and lipid-binding. Delineation of the structural motifs that mediate S100-target protein interactions and determination of the in vivo relevance of these interactions are needed to fully understand the role of S100 proteins in normal and diseased cells.     

Deployment of extracellular matrix proteins in sea urchin embryogenesis.

The apical extracellular matrix of the sea urchin embryo, known as the hyaline layer (HL), is a multi-laminate organelle composed of at least 10 polypeptides. Although integrated into one ECM, HL proteins exhibit individual temporal and spatial dynamics throughout development. These molecules are stockpiled in the oocyte during vitellogenesis in at least four distinct vesicle populations. They are released onto the cell surface at fertilization in a specific order, and interact differentially with embryonic cells as development proceeds. Many experiments have suggested that the HL is vital for embryogenesis, but relatively little is known about the functions and interactions of its constituent molecules. The purpose of the present review has been to gather information on the basic characteristics of the known HL proteins together with data on their expression in the embryo, and where possible, their biological activities. Compiled, these observations may provide some insight into the workings of a uniquely embryonic organelle.     

S-100 proteins in the human peripheral nervous system

This article reviews the distribution of S100 proteins in the human peripheral nervous system. The expression of S100 by peripheral glial cells seems to be a distinctive fact of these cells, independently of their localization and their ability to myelinate or not. S100 proteins expressing cells include satellite cells of sensory, sympathetic and enteric ganglia, supporting cells of the adrenal medulla, myelinating and non-myelinating Schwann cells in the nerve trunks, and the Schwann-related cells of sensory corpuscles. In addition, S100 proteins are expressed in peripheral neurons. Most of them express S100alpha protein, and a subpopulation of sensory neurons in dorsal root ganglia contains S100beta protein or S100alpha plus S100beta proteins.     

Immunohistochemical localization of S100-like protein in non-mammalian kidney

The immunolocalization of S100-like protein was investigated in the kidney of saltwater fishes (Dicentrarchus labrax; Coris julis; Serranus cabrilla; Scorpaena porcus), amphibia (Rana aesculenta), reptiles (Lacerta viridis), and aves (Gallus domesticus; Strutio camelus). S100-like immunoreactivity was detected in the juxtaglomerular cells of all saltwater fishes studied. No immunoreactivity was observed in other tracts of the nephron or in the interstitial tissue. In frog kidney, S100-like immunoreactive cells were localized in the proximal tubule, singly distributed or placed side by side in clusters of two or three cells. S100-like immunoreactive cells were distributed in the distal and in the collecting tubules in lizard, chicken, and ostrich kidney. In the distal tubule of lizard kidney, S100-like immunoreactive cells were numerous and uniformly distributed. In lizard collecting tubules, S100-like immunoreactive cells showed less intense immunoreactivity than in the distal tubule, except for a cluster of cells at the junction with the initial collecting duct. In chicken and ostrich kidney, S100-like immunoreactive cells of the distal tubules were closely packed together. In the collecting tubules, S100-like immunoreactive cells were alternate to negative cells. These results indicate the high conservation degree of S100 proteins through phylogenesis and suggest a functional role for these proteins in the vertebrate kidney.     

Monitoring of S100 homodimerization and heterodimeric interactions by the yeast two-hybrid system

The S100 family consists of 19 members, which function as transducers of calcium signals in a tissue-specific manner. Upon calcium binding, the conformation of many S100 proteins changes dramatically. Several hydrophobic residues are exposed, allowing the S100 proteins to interact with their target proteins, and thereby to transduce calcium signals into specific biological responses. To further elucidate the exact contribution of the S100 calciproteins in the calcium signalling pathways, several groups have applied the yeast two-hybrid technology to identify putative target proteins for the various S100 calciproteins. Two-hybrid large screens using S100 proteins as baits have confirmed the biochemical and structural feature of S100, which enable them to form homodimers and the ability of some members to form specific heterodimers in vivo. Yeast two-hybrid investigations have allowed the identification of conserved hydrophobic residues and domains that are crucial for the stabilization of S100 homo- and heterodimers. Furthermore, this method clearly underlines that the homo- and heterodimerization mechanisms differ among the members of the S100 family. However, several lines of evidence strongly suggest that two-hybrid methodology is limited to the analysis of interactions that are calcium-independent, since no target proteins other than S100 family members themselves have been detected with this methodology.     

基于S5PC100嵌入式平台的仓库监控系统设计

根据国内仓库监控的现状,设计并实现了一款基于嵌入式Linux的仓库监控系统。其前端以嵌入式S5PC100为控制核心,在对硬件和软件进行了总体设计之后,重点研究并实现了TCP/IP协议网络下的嵌入式前端TCP方式的温湿度及控制信号传输和UDP方式的视频传输,实现了基于Video4Linux（V4L）技术对视频图像信息的采集。经测试,系统稳定可靠、成本低、可扩展性强,在其他监控领域也有一定的参考价值。     

用XPS研究Na_2S钝化的GaAs(100)表面

本文用Na_2S·9H_2O的水溶液及乙醇和异丙醇溶液对GaAs表面进行了钝化处理;用X射线光电子能谱仪(XPS)对钝化表面的化学组成和价态以及钝化层的厚度进行了研究。结果表明,经不同的Na_2S溶液处理后GaAs表面的自然氧化层会被除去,表面生成硫化镓和硫化砷;硫化物的含量与硫化层厚度与所用溶液的极性有关;并对钝化机理进行了探讨。     

Three-dimensional volume reconstruction of extracellular matrix proteins in uveal melanoma from fluorescent confocal laser scanning microscope images

The distribution of looping patterns of laminin in uveal melanomas and other tumours has been associated with adverse outcome. Moreover, these patterns are generated by highly invasive tumour cells through the process of vasculogenic mimicry and are not therefore blood vessels. Nevertheless, these extravascular matrix patterns conduct plasma. The three‐dimensional (3D) configuration of these laminin‐rich patterns compared with blood vessels has been the subject of speculation and intensive investigation. We have developed a method for the 3D reconstruction of volume for these extravascular matrix proteins from serial paraffin sections cut at 4 µm thicknesses and stained with a fluorescently labelled antibody to laminin ( Maniotis et al., 2002 ). Each section was examined via confocal laser‐scanning focal microscopy (CLSM) and 13 images were recorded in the Z‐dimension for each slide. The input CLSM imagery is composed of a set of 3D subvolumes (stacks of 2D images) acquired at multiple confocal depths, from a sequence of consecutive slides. Steps for automated reconstruction included (1) unsupervised methods for selecting an image frame from a subvolume based on entropy and contrast criteria, (2) a fully automated registration technique for image alignment and (3) an improved histogram equalization method that compensates for spatially varying image intensities in CLSM imagery due to photo‐bleaching. We compared image alignment accuracy of a fully automated method with registration accuracy achieved by human subjects using a manual method. Automated 3D volume reconstruction was found to provide significant improvement in accuracy, consistency of results and performance time for CLSM images acquired from serial paraffin sections.     

Multiple structural states of S100A12: A key to its functional diversity

S100A12 is a member of the S100 family of EF-hand calcium-binding proteins. Together with two other calgranulins, S100A8 and S100A9, it is mostly expressed in human granulocytes, although there is increasing evidence of expression in keratinocytes and psoriatic lesions. It is involved in host-parasite response, and linked to corneal autoimmune diseases connected with filarial parasite infestation. Interaction of S100A12 with a multiligand receptor for advanced glycation end products (RAGE) mediates inflammation. Human recombinant S100A12 was found to induce neuritogenesis of cultured hippocampal cells, similar to two other S100 proteins, S100B and S100A4. X-ray structure of S100A12 has been solved in two crystal forms: R3 and P2(1). In the R3 crystal form S100A12 is a dimer, and in the P2(1) crystal form the dimers are arranged as a hexamer. The hexameric form suggests its role in receptor oligomerisation. S100A12 binds copper at the predicted zinc/copper binding site, which is located close to the surface of the protein. We propose copper-mediated generation of reactive oxygen species by S100A12 as its function in host-parasite response.     

Expression and distribution of S100 protein in the nervous system of the adult zebrafish (Danio rerio)

S100 proteins are EF-hand calcium-binding protein highly preserved during evolution present in both neuronal and non-neuronal tissues of the higher vertebrates. Data about the expression of S100 protein in fishes are scarce, and no data are available on zebrafish, a common model used in biology to study development but also human diseases. In this study, we have investigated the expression of S100 protein in the central nervous system of adult zebrafish using PCR, Western blot, and immunohistochemistry. The central nervous system of the adult zebrafish express S100 protein mRNA, and contain a protein of approximately 10 kDa identified as S100 protein. S100 protein immunoreactivity was detected widespread distributed in the central nervous system, labeling the cytoplasm of both neuronal and non-neuronal cells. In fact, S100 protein immunoreactivity was primarily found in glial and ependymal cells, whereas the only neurons displaying S100 immunoreactivity were the Purkinje's neurons of the cerebellar cortex and those forming the deep cerebellar nuclei. Outside the central nervous system, S100 protein immunoreactivity was observed in a subpopulation of sensory and sympathetic neurons, and it was absent from the enteric nervous system. The functional role of S100 protein in both neurons and non-neuronal cells of the zebrafish central nervous system remains to be elucidated, but present results might serve as baseline for future experimental studies using this teleost as a model.     

Immunolocalization of S100-like protein in the brain of an emerging model organism: Nothobranchius furzeri

The S100 protein in nervous tissue appears to play important roles in regulating neuronal differentiation, glial proliferation, plasticity, development, axonal growth, and in neurogenetic processes. In fish, the adult neurogenic activity is much higher than in mammals. In this study, the localization of S100 protein was investigated in the brain of annual teleost fish, Nothobranchius furzeri, which is an emerging model organism for aging research. By immunohistochemical techniques, S100 immunoreactivity (IR) was detected in glial cells, small neurons, and fibers throughout all regions of central nervous system (CNS) with different pattern of distribution. In the telencephalon, S100 IR was seen in the olfactory bulbs and in different areas of the telencephalic hemispheres. In the diencephalon, S100 positivity was observed in the habenular nuclei of the epithalamus, in the cortical thalamic nucleus, in the dorsal, ventral and caudal portions, the latter with the posterior recessus nucleus, and in the diffuse inferior lobe of the hypothalamus, along the diencephalic ventricle and in the dorsal optic tract. In the mesencephalon, S100 IR was observed in the longitudinal tori, in the optic tectum, and along the mesencephalic ventricle. In the rhombencephalon, S100 IR was shown in valvula and body of the cerebellum, and in some nuclei of the medulla oblongata. The results suggest that S100 may play a key role in the maintenance of the CNS and in neurogenesis processes in the adulthood.     

Effect of sugars on the association between cowpea vicilin (7S storage proteins) and fungal cells

Vicilins (7S storage proteins) found in various legume seeds have been previously shown to interfere with the germination of spores or conidia of phytopathogenic fungi and inhibit yeast growth and glucose stimulated acidification of the medium by yeast cells. In the present work vicilins from cowpea (Vigna unguiculata) seeds were added to the growth medium of Saccharomyces cerevisiae cells and Fusarium oxysporum conidia. Helix pomatia lectin, wheat germ agglutinin and Ulex europaeus lectin were used to identify differences in the binding of the vicilins to the surface of cells of S. cerevisiae and F. oxysporum treated with this protein. After the growth period, the material in suspension (yeast cells) was centrifuged and the final pellet was also treated with different sugar (glucose, sucrose, glucosamine, N-acetyl-glucosamine) concentrations and 0.1 M HCl for extraction of vicilins associated to chitinous structures present in yeast cells. Our results showed that vicilin sub-units were present in the different sugar extracts of yeast cells pretreated with the vicilins and these proteins were eluted by 0.5 M solutions of sugars in the following order of efficiency of elution: N-acetyl-glucosamine, sucrose/glucose and glucosamine.     

Frog p26olf,a molecule with two S100-like regions in a single peptide

An S100-like calcium-binding protein, p26olf, was originally isolated from the frog (Rana Catesbeiana) olfactory epithelium with four chromatographical steps. The primary structure of p26olf contains two S100-like regions aligned in tandem with four functional EF-hands. At 100 mM K(+), wild-type p26olf binds Ca(2+) with a Kd value of 22 microM and a Hill coefficient of 2.0. Each EF-hand seems to have different affinity for Ca(2+): it is high in EF-A and -B and low in EF-C and -D. In our Ca(2+)-binding model, the order of Ca(2+)-binding to p26olf is EF-B, EF-A, EF-C, and EF-D. Expression of mRNA of p26olf is detected in various frog tissues: it is high in the olfactory epithelium, lung, and spleen, moderate in brain, retina, heart, and kidney, and low in liver and muscle. Immunohistochemical studies revealed that p26olf is prominently localized in the cilia of both olfactory and lung respiratory epithelium and especially enriched in the distal segment of the olfactory cilia. Several proteins in the olfactory cilia bind to p26olf in the presence of Ca(2+), suggesting that they are possible target proteins of p26olf. One of these target proteins is immunologically identified as a beta-adrenergic receptor kinase-like protein. In the olfactory cilia, p26olf may have some roles in the olfactory transduction or adaptation through interaction with this beta-adrenergic receptor kinase-like protein.     

Laminins and their roles in mammals

Laminins are alpha-beta-gamma heterotrimeric components of all basement membranes. Laminins are now known to play the central role in organizing and establishing the basement membrane. The diversity of laminins allows them to impart special structural and signaling properties to the basement membrane. Of the 12 known laminin chain genes, 10 have been either found to be mutated in humans or experimentally mutated in mice. This has led to great progress over the last several years towards understanding both the functions of laminins and the reasons for their great diversity. In this review, I will summarize the in vivo studies in mice and humans that have contributed to this new knowledge.