Structural Proteins (structural + protein)

Distribution by Scientific Domains
Distribution within Life Sciences


Selected Abstracts


Comparative analysis of the widespread and conserved PB1-like viruses infecting Pseudomonas aeruginosa

ENVIRONMENTAL MICROBIOLOGY, Issue 11 2009
Pieter-Jan Ceyssens
Summary We examined the genetic diversity of lytic Pseudomonas aeruginosa bacteriophage PB1 and four closely related phages (LBL3, LMA2, 14-1 and SN) isolated throughout Europe. They all encapsulate linear, non-permuted genomes between 64 427 and 66 530 bp within a solid, acid-resistant isometric capsid (diameter: 74 nm) and carry non-flexible, contractile tails of approximately 140 nm. The genomes are organized into at least seven transcriptional blocks, alternating on both strands, and encode between 88 (LBL3) and 95 (LMA2) proteins. Their virion particles are composed of at least 22 different proteins, which were identified using mass spectrometry. Post-translational modifications were suggested for two proteins, and a frameshift hotspot was identified within ORF42, encoding a structural protein. Despite large temporal and spatial separations between phage isolations, very high sequence similarity and limited horizontal gene transfer were found between the individual viruses. These PB1-like viruses constitute a new genus of environmentally very widespread phages within the Myoviridae. [source]


CAST2: identification and characterization of a protein structurally related to the presynaptic cytomatrix protein CAST

GENES TO CELLS, Issue 1 2004
Maki Deguchi-Tawarada
The cytomatrix at the active zone (CAZ) is thought to define the site of Ca2+ -dependent exocytosis of neurotransmitters. We have recently identified a novel CAZ protein from rat brain which we have named CAST (CAZ-associated structural protein). CAST forms a large molecular complex with other CAZ proteins such as Bassoon, RIM1 and Munc13-1, at least through direct binding to RIM1. Here, we have identified a rat protein that is structurally related to CAST and named it CAST2. Subcellular fractionation analysis of rat brain shows that CAST2 is also tightly associated with the postsynaptic density fraction. Like CAST, CAST2 directly binds RIM1 and forms a hetero-oligomer with CAST. In primary cultured rat hippocampal neurones, CAST2 co-localizes with Bassoon at synapses. Furthermore, immunoelectron microscopy reveals that CAST2 localizes to the vicinity of the presynaptic membrane of synapses in mouse brain. Sequence analysis reveals that CAST2 is a rat orthologue of the human protein ELKS. ELKS has also recently been identified as Rab6IP2 and ERC1. Accordingly, the original CAST is tentatively re-named CAST1. These results indicate that CAST2 is a new component of the CAZ and, together with CAST1, may be involved in the formation of the CAZ structure. [source]


Caveolin-1 secreting LNCaP cells induce tumor growth of caveolin-1 negative LNCaP cells in vivo

INTERNATIONAL JOURNAL OF CANCER, Issue 3 2008
René Bartz
Abstract Caveolin-1 (Cav-1) was originally identified as a structural protein of caveolae, which is a plasma membrane domain that regulates a variety of signaling pathways involved in cell growth and migration. Here, we show that expression of Cav-1 in the Cav-1-deficient human prostate cancer cell line LNCaP both stimulates cell proliferation and promotes tumor growth in nude mice. Unexpectedly, Cav-1 expressing LNCaP (LNCaPCav-1) cells injected into one side of a nude mouse promoted tumor growth of Cav-1 negative LNCaP cells injected on the contralateral side of the same animal. The LNCaP tumors were positive for Cav-1, however, this signal was not caused by migrated LNCaPCav-1 cells, but we show that this Cav-1 was secreted by the LNCaPCav-1 tumors. We demonstrate that conditioned media from LNCaPCav-1 cells contained Cav-1 that was associated with a lipoprotein particle ranging in size from 15 to 30 nm and a density similar to high density lipoprotein particle. These results suggest that LNCaPCav-1 cells secreting Cav-1 particle produce an endocrine factor that stimulates tumor growth. © 2007 Wiley-Liss, Inc. [source]


Chaperone-like activity and hydrophobicity of ,-crystallin

IUBMB LIFE, Issue 11 2006
G. Bhanuprakash Reddy
Abstract ,-Crystallin, a prominent member of small heat shock protein (sHsp) family and a major structural protein of the eye lens is a large polydisperse oligomer of two isoforms, ,A- and ,B-crystallins. Numerous studies have demonstrated that ,-crystallin functions like a molecular chaperone in preventing the aggregation of various proteins under a wide range of stress conditions. The molecular chaperone function of ,-crystallin is thus considered to be vital in the maintenance of lens transparency and in cataract prevention. ,-Crystallin selectively interacts with non-native proteins thereby preventing them from aggregation and helps maintain them in a folding competent state. It has been proposed and generally accepted that ,-crystallin suppresses the aggregation of other proteins through the interaction between hydrophobic patches on its surface and exposed hydrophobic sites of partially unfolded substrate protein. However, a quantifiable relationship between hydrophobicity and chaperone-like activity remains a matter to be concerned about. On an attentive review of studies on ,-crystallin chaperone-like activity, particularly the studies that have direct or indirect implications to hydrophobicity and chaperone-like activity, we found several instances wherein the correlation between hydrophobicity and its chaperone-like activity is paradoxical. We thus attempted to provide an overview on the role of hydrophobicity in chaperone-like activity of ,-crystallin, the kind of evaluation done for the first time. iubmb Life, 58: 632 - 641, 2006 [source]


Gelatin-based biomimetic tissue adhesive.

JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2006
Potential for retinal reattachment
Abstract An adhesive that cures under moist/wet conditions could facilitate surgical procedures for retinal reattachment. We are investigating an adhesive that mimics the factor XIIIa-mediated crosslinking of fibrin that occurs in the late stages of the blood coagulation cascade. Specifically, we use gelatin as the structural protein (in place of fibrin), and crosslink gelatin using a calcium-independent microbial transglutaminase (in place of the calcium-dependent transglutaminase factor XIIIa). Injection of gelatin and microbial transglutaminase (mTG) into the vitreous cavity of Sprague Dawley white rats did not elicit structural or cellular damage to the retina as evidenced from histological evaluation 2 weeks post-injection. Qualitative in vitro studies indicate that the gelatin,mTG adhesive binds to bovine retinal tissue under wet conditions. Quantitative lap-shear tests were performed with more robust bovine tissue from the choroid and sclera. The lap-shear strength of the biomimetic gelatin,mTG adhesive was independent of tissue-type and ranged from 15 to 45 kPa, which is comparable to the values reported for other soft-tissue adhesives. These studies suggest that the mTG-crosslinked gelatin may provide a simple, safe, and effective adhesive for ophthalmic applications. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006 [source]


Macrobrachium rosenbergii nodavirus infection in M. rosenbergii (de Man) with white tail disease cultured in Taiwan

JOURNAL OF FISH DISEASES, Issue 6 2008
C S Wang
Abstract White tail disease (WTD) is a serious problem in Macrobrachium rosenbergii hatcheries and nursery ponds in Asia. The causative agents have been identified as M. rosenbergii nodavirus (MrNV) and its associated extra small virus. This is the first report demonstrating MrNV virus in M. rosenbergii displaying WTD signs in Taiwan by reverse transcriptase-polymerase chain reaction (RT-PCR). Amplified fragments of 850 and 425 bp for RNA-1 and RNA-2 of MrNV, respectively, were obtained by RT-PCR. RT-PCR products of about 850 and 1121 bp for RNA-1 and RNA-2 of MrNV were also obtained using different primer pairs. The amplicons were individually cloned into pGEM-T vector and sequenced. Using this recombinant plasmid of MrNV RNA-2 as DNA template, the non-radioactive DNA probes were prepared by PCR amplification with DIG,11-dUTP. The probes were used to successfully detect MrNV infection in the striated muscle tissues of WTD-diseased prawns using in situ hybridization. The 1121 bp genomic fragment of RNA-2 of MrNV consisted of a unique open reading frame with 1116 nucleotides, and it encoded a structural protein with 371 amino acids. The nucleotide sequence of the partial genome of MrNV RNA-2 revealed a 97% identity with an Indian isolate. A phylogenetic tree constructed using the nucleotide sequence of the viral capsid gene from insect and fish nodaviruses revealed that the MrNV Taiwan isolate could be interpreted as a new genus within the family Nodaviridae. However, its position showed more affinity with Alphanodavirus than with Betanodavirus. The study confirmed the presence of MrNV infection in freshwater prawns cultured in Taiwan suffering from WTD. [source]


A study of juvenile rat spinal cord injury

JOURNAL OF NEUROCHEMISTRY, Issue 2002
J. M. Wingrave
Greater than 5% of all spinal cord injuries (SCI) in the US occur in people younger than 16, although a minority, children will require extended attention during their lifetime. While facing increased mortality in the initial 24 h after trauma, children with incomplete injuries seem to have a greater capacity for recovery of function compared to adults suggesting that there is a difference in injury tolerance in the young over the adult. Knowledge of the factors involved in this difference would not only increase understanding of SCI, but also potentiate new avenues for SCI treatment. Yet there has not been a model for the study of youth SCI. For these reasons, we developed a model of SCI in juvenile rats equivalent to an adult injury of 25 g cm force (GCF). To do so, we recorded spinal cord masses of Sprague,Dawley rats at 21, 30, 45, and 60 days of age, compared them to adult cord masses, and assembled a conversion factor that provides youth injuries comparable to adult. To investigate the pathophysiology in juvenile SCI, two cord segments, 1 cm long, were removed from animals 24 h following injury. One segment was centered at the impact site, the other immediately caudal. After homogenization, the samples were assayed by Western blot analysis for calpain content and degradation of 68K Neuro-Filament Protein (68K NFP), a neuronal structural protein. mCalpain expression, a neutral protease previously implicated in secondary SCI, was reduced in juvenile animals relative to adult cohorts. The degradation of 68K NFP was also found to be reduced in juvenile animals. From these analyses, it seems plausible that calpain expression and pathogenic activity is abated in the setting of young rat SCI. Acknowledgements:, Supported by grants from NIH-NINDS. [source]


Properties of the hepatitis C virus core protein: a structural protein that modulates cellular processes

JOURNAL OF VIRAL HEPATITIS, Issue 1 2000
McLauchlan
The core protein of hepatitis C virus (HCV) is believed to form the capsid shell of virus particles. Maturation of the protein is achieved through cleavage by host cell proteases to give a product of 21 000 MW, which is found in tissue culture systems and sera from infected individuals. However, efficient propagation of the virus is not possible at present in tissue culture. Hence, studies have focused on the properties of the core protein and its possible role in pathologies associated with HCV infection. This review describes key features of the polypeptide and the status of current knowledge on its ability to influence several cellular processes. [source]


Streptococcus pyogenes pili promote pharyngeal cell adhesion and biofilm formation

MOLECULAR MICROBIOLOGY, Issue 4 2007
Andrea G. O. Manetti
Summary Group A Streptococcus (GAS, Streptococcus pyogenes) is a Gram-positive human pathogen responsible for several acute diseases and autoimmune sequelae that account for half a million deaths worldwide every year. GAS infections require the capacity of the pathogen to adhere to host tissues and assemble in cell aggregates. Furthermore, a role for biofilms in GAS pathogenesis has recently been proposed. Here we investigated the role of GAS pili in biofilm formation. We demonstrated that GAS pilus-negative mutants, in which the genes encoding either the pilus backbone structural protein or the sortase C1 have been deleted, showed an impaired capacity to attach to a pharyngeal cell line. The same mutants were much less efficient in forming cellular aggregates in liquid culture and microcolonies on human cells. Furthermore, mutant strains were incapable of producing the typical three-dimensional layer with bacterial microcolonies embedded in a carbohydrate polymeric matrix. Complemented mutants had an adhesion and aggregation phenotype similar to the wild-type strain. Finally, in vivo expression of pili was indirectly confirmed by demonstrating that most of the sera from human patients affected by GAS-mediated pharyngitis recognized recombinant pili proteins. These data support the role of pili in GAS adherence and colonization and suggest a general role of pili in all pathogenic streptococci. [source]


Human papillomavirus L1 protein expressed in tobacco chloroplasts self-assembles into virus-like particles that are highly immunogenic

PLANT BIOTECHNOLOGY JOURNAL, Issue 5 2008
Alicia Fernández-San Millán
Summary Cervical cancer is the second most prevalent cancer in women worldwide. It is linked to infection with human papillomavirus (HPV). As the virus cannot be propagated in culture, vaccines based on virus-like particles have been developed and recently marketed. However, their high costs constitute an important drawback for widespread use in developing countries, where the incidence of cervical cancer is highest. In a search for alternative production systems, the major structural protein of the HPV-16 capsid, L1, was expressed in tobacco chloroplasts. A very high yield of production was achieved in mature plants (~3 mg L1/g fresh weight; equivalent to 24% of total soluble protein). This is the highest expression level of HPV L1 protein reported in plants. A single mature plant synthesized ~240 mg of L1. The chloroplast-derived L1 protein displayed conformation-specific epitopes and assembled into virus-like particles, visible by transmission electron microscopy. Furthermore, leaf protein extracts from L1 transgenic plants were highly immunogenic in mice after intraperitoneal injection, and neutralizing antibodies were detected. Taken together, these results predict a promising future for the development of a plant-based vaccine against HPV. [source]


Black and white , does melanin change the bulk carbon and nitrogen isotope values of feathers?

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 7 2010
Andreas Michalik
Bird feathers are employed in a wide range of carbon and nitrogen isotope studies relating to diet and migration. Feathers are chemically inert with respect to carbon and nitrogen, after synthesis. It has always been assumed that feathers show isotope values characteristic of keratin, a fibrous structural protein from which they are formed. Little attention has been paid to other components of feathers such as melanin or carotenoids. Melanin is synthesized from tyrosine, which is depleted in both 13C and 15N. We compared isotope values of coeval black and white feathers in four different species. Black feather parts were in all cases significantly depleted in 13C relative to white feather parts but in most species no clear trend was discernable for 15N. We suggest that additional evaluation may be required to characterize the carbon and nitrogen isotope contribution of feather pigments like carotenoids. Care should be taken in future stable isotope studies when comparing differently coloured feathers. Copyright © 2010 John Wiley & Sons, Ltd. [source]


Getting the best out of long-wavelength X-rays: de novo chlorine/sulfur SAD phasing of a structural protein from ATV

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 3 2010
Adeline Goulet
The structure of a 14,kDa structural protein from Acidianus two-tailed virus (ATV) was solved by single-wavelength anomalous diffraction (SAD) phasing using X-ray data collected at 2.0,Å wavelength. Although the anomalous signal from methionine sulfurs was expected to suffice to solve the structure, one chloride ion turned out to be essential to achieve phasing. The minimal data requirements and the relative contributions of the Cl and S atoms to phasing are discussed. This work supports the feasibility of a systematic approach for the solution of protein crystal structures by SAD based on intrinsic protein light atoms along with associated chloride ions from the solvent. In such cases, data collection at long wavelengths may be a time-efficient alternative to selenomethionine substitution and heavy-atom derivatization. [source]


Lipoprotein Mutation Accelerates Substrate Permeability-Limited Toluene Dioxygenase-Catalyzed Reaction

BIOTECHNOLOGY PROGRESS, Issue 3 2005
Ye Ni
One of the major problems in whole-cell biocatalysis is its low reaction rate. The underlying cause is the substrate permeation barrier presented by cell envelopes. The present research investigates mutation effects of the Braunapos;s lipoprotein, the most abundant outer membrane structural protein in Escherichia coli, on toluene dioxyengase (TDO)-catalyzed reaction. Dramatic enhancement of the reaction rate, an increase of up to 6-fold, was observed with the mutant for all three small, hydrophobic substrates tested (toluene, ethylbenzene, and 2-indanone). The increase was observed over a wide range of substrate concentrations (0.1,5 mM). The mutant exhibited a normal growth rate and expressed the recombinant multicomponent enzyme as well as the isogenic parent strain. Taken together, the lipoprotein mutant expressing TDO is a much better whole-cell catalyst for the oxidation reaction. The beneficial effect of the lipoprotein mutation may be general for a broad range of substrates and enzyme systems as the mutation affects the global integrity of the cell membrane. A comparison of the mutation effect with a common permeabilizing procedure, the EDTA treatment, further illustrates the clear advantages of using genetic modification in cellular membrane engineering for improved whole-cell catalysts. [source]


Separation of Pure and Immunoreactive Virus-Like Particles Using Gel Filtration Chromatography Following Immobilized Metal Ion Affinity Chromatography

BIOTECHNOLOGY PROGRESS, Issue 2 2001
Yu-Shen Cheng
A purification process was developed to obtain highly pure rVP2H particles, formed by a structural protein (VP2) of the infectious bursal disease virus (IBDV) with six additional histidine residues at its C-terminus. The ultimate goal was the development of an efficient subunit vaccine against IBDV infection. The particles within the infected High-Five (Hi-5) cell lysates were partially purified by employing immobilized metal ion (Ni2+) affinity chromatography (IMAC). The initial step could recover approximately 85% of immunoreactive rVP2H proteins but failed to separate the rVP2H particles from the free rVP2H proteins or its degraded products. To separate the particulate form from the free form of rVP2H, an additional step was added, which used either gel filtration chromatography or CsCl density gradient ultracentrifugation. Both were able to produce extremely pure rVP2H particles with a buoyant density close to 1.27 g/cm3. However, the former method can process a larger sample volume than does the latter. By integrating IMAC and gel filtration chromatography, 1 mg of extremely pure rVP2H particles was routinely obtained from a 500 mL Hi-5 cell culture broth. The separation of the particulate form from the free form of rVP2H proteins exposes their respective immunogenicity to induce the virus-neutralizing antibodies and the ability to protect chickens from IBDV infection. Additionally, the abundant quantities of pure rVP2H particles coupled with their uniform dimensions facilitates an understanding of higher order structure of the immunogenic particles and can therefore result in improved vaccines against the virus. [source]


Vascular smooth muscle cell phenotypic modulation in culture is associated with reorganisation of contractile and cytoskeletal proteins

CYTOSKELETON, Issue 3 2001
Nathalie F. Worth
Abstract Smooth muscle cells (SMC) exhibit a functional plasticity, modulating from the mature phenotype in which the primary function is contraction, to a less differentiated state with increased capacities for motility, protein synthesis, and proliferation. The present study determined, using Western analysis, double-label immunofluorescence and confocal microscopy, whether changes in phenotypic expression of rabbit aortic SMC in culture could be correlated with alterations in expression and distribution of structural proteins. "Contractile" state SMC (days 1 and 3 of primary culture) showed distinct sorting of proteins into subcellular domains, consistent with the theory that the SMC structural machinery is compartmentalised within the cell. Proteins specialised for contraction (,-SM actin, SM-MHC, and calponin) were highly expressed in these cells and concentrated in the upper central region of the cell. Vimentin was confined to the body of the cell, providing support for the contractile apparatus but not co-localising with it. In line with its role in cell attachment and motility, ,-NM actin was localised to the cell periphery and basal cortex. The dense body protein ,-actinin was concentrated at the cell periphery, possibly stabilising both contractile and motile apparatus. Vinculin-containing focal adhesions were well developed, indicating the cells' strong adhesion to substrate. In "synthetic" state SMC (passages 2,3 of culture), there was decreased expression of contractile and adhesion (vinculin) proteins with a concomitant increase in cytoskeletal proteins (,-non-muscle [NM] actin and vimentin). These quantitative changes in structural proteins were associated with dramatic changes in their distribution. The distinct compartmentalisation of structural proteins observed in "contractile" state SMC was no longer obvious, with proteins more evenly distributed throughout the cytoplasm to accommodate altered cell function. Thus, SMC phenotypic modulation involves not only quantitative changes in contractile and cytoskeletal proteins, but also reorganisation of these proteins. Since the cytoskeleton acts as a spatial regulator of intracellular signalling, reorganisation of the cytoskeleton may lead to realignment of signalling molecules, which, in turn, may mediate the changes in function associated with SMC phenotypic modulation. Cell Motil. Cytoskeleton 49:130,145, 2001. © 2001 Wiley-Liss, Inc. [source]


Multipass Treatment of Photodamage Using the Pulse Dye Laser

DERMATOLOGIC SURGERY, Issue 7 2003
Emil A. Tanghetti MD
Background. Pulse dye lasers (PDLs) alter structural proteins in scars and photodamaged skin, in addition to their effects on dermal vasculature. The PDL has become an option in the treatment of photodamage. Although improvements to skin texture are generally modest when compared with ablative resurfacing, PDL offers a treatment with few side effects. A number of methods have been proposed in an effort to improve treatment outcomes. These range from single, low-fluence treatment with no purpura to multiple passes and treatment sessions as well as purpuric doses. Objective. To evaluate several of the PDL treatment methods to improve photorejuvenation outcomes while limiting the risk of side effects. Methods. Twenty patients with photodamage were separated into two groups. Each group received a series of four single-pass treatments or four double-pass treatments at 2-week intervals. Treatments were done using a 595-nm PDL (PhotoGenica V-Star) and a 585-nm PDL (PhotoGenica V) at a pulse duration of 0.5 ms and a 10-mm handpiece. Treatment fluences were maintained below the individual's purpuric threshold, ranging from 3 to 4 J/cm2. Photos were taken before treatment and during follow-up. Efficacy of treatment was based on subjective grading of photos and by patient self-reporting. Results. Multiple treatments resulted in improvements to skin tone and texture, including a reduction in the appearance of rhytids and, in particular, improved pigmentary evenness. There was no significant difference between laser or treatment methods. No side effects were noted. Conclusion. PDL treatments provide effective photorejuvenation with minimal risk of side effects. [source]


An effective skeletal muscle prefractionation method to remove abundant structural proteins for optimized two-dimensional gel electrophoresis

ELECTROPHORESIS, Issue 11 2005
Bradley Jarrold
Abstract Proteomic analysis of biological samples in disease models or therapeutic intervention studies requires the ability to detect and identify biologically relevant proteins present in relatively low concentrations. The detection and analysis of these low-level proteins is hindered by the presence of a few proteins that are expressed in relatively high concentrations. In the case of muscle tissue, highly abundant structural proteins, such as actin, myosin, and tropomyosin, compromise the detection and analysis of more biologically relevant proteins. We have developed a practical protocol which exploits high-pH extraction to reduce or remove abundant structural proteins from skeletal muscle crude membrane preparations in a manner suitable for two dimensional gel electrophoresis. An initial whole-cell muscle lysate is generated by homogenization of powdered tissue in Tris-base. This lysate is subsequently partitioned into a supernatant and pellet containing the majority of structural proteins. Treatment of the pellet with high-pH conditions effectively releases structural proteins from membrane compartments which are then removed through ultracentrifugation. Mass spectrometric identification shows that the majority of protein spots reduced or removed by high-pH treatment were contractile proteins or contractile-related proteins. Removal of these proteins enabled successful detection and identification of minor proteins. Structural protein removal also results in significant improvement of gel quality and the ability to load higher amounts of total protein for the detection of lower abundant protein classes. [source]


Altered subcellular location of phosphorylated Smads in Alzheimer's disease

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2006
Uwe Ueberham
Abstract A number of growth factors and cytokines, such as transforming growth factor beta 1 (TGF-,1), is elevated in Alzheimer's disease (AD), giving rise to activated intracellular mitogenic signaling cascades. Activated mitogenic signaling involving the mitogen-activated protein kinases (MAPKs) and other protein kinases might alter the phosphorylation states of structural proteins such as tau, resulting in hyperphosphorylated deposits. Many intracellular signaling proteins are potential targets of misregulated phosphorylation and dephosphorylation. Recently, a crosstalk between MAPKs and Smad proteins, both involved in mediating TGF-,1 signaling, has been reported. Although TGF-,1 has previously been shown to be involved in the pathogenesis of AD, the role of Smad proteins has not been investigated. In this study we thus analysed the subcellular distribution of phosphorylated Smad2 and Smad3 in the hippocampus of both normal and AD brains. Here we report on strong nuclear detection of phosphorylated Smad2 and Smad3 in neurons of control brains. In AD brains these phosphorylated proteins were additionally found in cytoplasmic granules in hippocampal neurons, within amyloid plaques and attached to neurofibrillary tangles. Our data suggest a critical role of Smad proteins in the pathogenesis of AD. [source]


Developmental changes in cellular and extracellular structural macromolecules in the secondary palate and in the nasal cavity of the mouse

EUROPEAN JOURNAL OF ORAL SCIENCES, Issue 3 2010
Forugh Vaziri Sani
Vaziri Sani F, Kaartinen V, El Shahawy M, Linde A, Gritli-Linde A. Developmental changes in cellular and extracellular structural macromolecules in the secondary palate and nasal cavity of the mouse. Eur J Oral Sci 2010; 118: 221,236. © 2010 The Authors. Journal compilation© 2010 Eur J Oral Sci The aim of this study was to analyse the hitherto largely unknown expression patterns of some specific cellular and extracellular molecules during palate and nasal cavity development. We showed that epithelia of the developing palate and the vomerine epithelium express similar sets of structural proteins. With the exception of keratin 15, which becomes barely detectable in the elevated palatal shelves, nearly all of these proteins become upregulated at the presumptive areas of fusion and in the adhering epithelia of the palate and nasal septum. In vivo and in vitro analyses indicated that reduction in the amount of keratin 15 protein is independent of Tgf,,Alk5 signalling. Foxa1 expression also highlighted the regionalization of the palatal and nasal epithelia. Owing to the lack of reliable markers of the palatal periderm, the fate of peridermal cells has been controversial. We identified LewisX/stage-specific embryonic antigen-1 as a specific peridermal marker, and showed that numerous peridermal cells remain trapped in the medial epithelial seam (MES). The fate of these cells is probably apoptosis together with the rest of the MES cells, as we provided strong evidence for this event. Heparan sulphate, chondroitin-6-sulphate, and versican displayed dynamically changing distribution patterns. The hitherto-unknown innervation pattern of the developing palate was revealed. These findings may be of value for unravelling the pathogenesis of palatal clefting. [source]


Mechanisms of blister induction by autoantibodies

EXPERIMENTAL DERMATOLOGY, Issue 12 2005
Cassian Sitaru
Abstract:, Autoimmune diseases are characterized by defined self-antigens, organ specificity, autoreactive T cells and/or autoantibodies that can transfer disease. Autoimmune blistering diseases are organ-specific autoimmune diseases associated with an immune response directed to structural proteins mediating cell,cell and cell,matrix adhesion in the skin. While both autoreactive T and B cells have been detected and characterized in patients with autoimmune blistering diseases, current evidence generally supports a pathogenic role of autoantibodies for blister formation. The immunopathology associated with blisters induced by autoantibodies relies on several mechanisms of action. Autoantibodies from patients with pemphigus diseases can exert a direct effect just by binding to their target mediated by steric hindrance and/or by triggering the transduction of a signal to the cell. In most subepidermal autoimmune blistering conditions, in addition to the binding to their target antigen, autoantibodies need to interact with factors of the innate immune system, including the complement system and inflammatory cells, in order to induce blisters. Generally, decisive progress has been made in the characterization of the mechanisms of blister formation in autoimmune skin diseases. However, various aspects, including the exact contribution of steric hindrance and signal transduction for pemphigus IgG-induced acantholysis or the fine tuning of the inflammatory cascade triggered by autoantibodies in some subepidermal blistering diseases, still need to be addressed. Understanding the mechanisms by which autoantibodies induce blisters should facilitate the development of more specific therapeutic strategies of autoimmune blistering diseases. [source]


Antibodies Against Hepatitis C Virus,Like Particles and Viral Clearance in Acute and Chronic Hepatitis C

HEPATOLOGY, Issue 3 2000
Thomas F. Baumert M.D.
We recently described the efficient assembly of hepatitis C virus (HCV) structural proteins into HCV-like particles (HCV-LPs) in insect cells. These noninfectious HCV-LPs have similar morphologic and biophysical properties as putative virions isolated from HCV-infected humans and can induce a broadly directed immune response in animal models. The HCV envelope proteins of HCV-LPs are presumably presented in a native, virion-like conformation and may therefore interact with antienvelope antibodies directed against conformational epitopes. In this study, HCV-LPs were used as capture antigens in an enzyme-linked immunosorbent assay (ELISA) to detect and quantify antibodies against HCV structural proteins in patients with acute and chronic hepatitis C. High titers of anti,HCV-LP antibodies were detected in patients chronically infected with HCV genotypes 1 to 6. In contrast to individuals with chronic hepatitis C, patients with acute self-limited hepatitis C displayed only a transient and weak seroreactivity against HCV-LPs. Patients with chronic HCV infection successfully treated with interferon demonstrated a gradual decline of anti,HCV-LP titers during or subsequent to viral clearance. Sustained interferon responders were characterized by significantly higher pretreatment levels of anti,HCV-LP antibodies as compared with nonresponders (P = .0001). In conclusion, HCV infection is associated with limited humoral immunity against the envelope proteins present on the HCV-LPs. An HCV-LP,based ELISA may be a useful diagnostic tool to distinguish acute hepatitis C from chronic HCV infection with exacerbation, and to predict viral clearance in response to interferon. [source]


The utility of cytokeratin subsets in distinguishing Barrett's-related oesophageal adenocarcinoma from gastric adenocarcinoma

HISTOPATHOLOGY, Issue 4 2001
A H Ormsby
Aims: Accurate tumour classification is critical for meaningful epidemiological studies in the assessment of cancer incidence rates and trends. Differentiating primary gastric carcinoma from oesophageal carcinoma can be difficult, especially when tumours are large and involve both the oesophagus and stomach. Furthermore, adenocarcinomas of both organs typically are of intestinal histological type and arise in a background of intestinal metaplasia. Consequently, histological markers that reliably distinguish Barrett's-related oesophageal adenocarcinoma from gastric adenocarcinoma would be useful. Cytokeratins (CK)7 and 20 are cytoplasmic structural proteins with restricted expression that help to determine the origin of many epithelial tumours including those of the gastrointestinal tract. The aim of this study was to determine the utility of co-ordinate CK7 and 20 expression in the distinction of Barrett's-related oesophageal adenocarcinoma from gastric adenocarcinoma arising in a background of intestinal metaplasia. Methods and results: CK7 and 20 immunostaining was performed on randomly selected surgical resection specimens from patients with Barrett's-related oesophageal adenocarcinoma (n = 30) and intestinal type gastric adenocarcinoma (n = 14) arising in a background of intestinal metaplasia. A CK7+ CK20- immunophenotype was demonstrated in 27 of 30 (90%) patients with Barrett's-related oesophageal adenocarcinoma and only three of 14 (21%) gastric adenocarcinomas. The sensitivity, specificity and positive predictive value of a CK7+/20, immunophenotype for a diagnosis of Barrett's-related oesophageal adenocarcinoma was 90%, 79%, and 90%, respectively. Conclusions: A CK7+/20, tumour immunophenotype is associated with Barrett's-related oesophageal adenocarcinoma and may be useful in accurate tumour classification, thus facilitating improving epidemiological evaluation of tumours at the oesophagogastric junction. [source]


HERV-K(HML-2) GAG/ENV antibodies as indicator for therapy effect in patients with germ cell tumors

INTERNATIONAL JOURNAL OF CANCER, Issue 3 2004
Anna Kleiman
Abstract Germ cell tumors (GCT) are strictly associated with the expression of HERV-K(HML-2) proviruses, and the majority of GCT patients produce antibodies to structural proteins of these proviruses. The objective of our study was to determine the significance of the serological response to HERV-K(HML-2) Gag and Env proteins for diagnosis, management of GCT patients and estimation of the therapy success. The data document a strong association of HERV-K(HML-2) antibodies and the clinical manifestation of the disease and therapy success. HERV-K(HML-2) antibodies seem to have an important diagnostic value as well as indicator of chemotherapy success. © 2004 Wiley-Liss, Inc. [source]


pH-induced alterations in stratum corneum properties

INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 3 2003
K. P. Ananthapadmanabhan
Synopsis Skin-cleansing compositions based on alkyl carboxylates (soaps) have a higher irritation potential than those based on syndet surfactants such as alkyl isethionates or alkyl ether sulphates. Contributing factors include inherent differences in the irritation potential of soaps and syndet surfactants, pH-induced changes in surfactant solution chemistry, and the direct effects of pH on the physical properties of the stratum corneum (SC). Past work has not directly addressed the effect of solution pH on the SC itself and its potential role in cleanser-induced skin irritation. In the current work, alterations to SC properties induced by buffered pH solutions and two strongly ionizable surfactants, sodium dodecyl sulphate and sodium lauryl ether sulphate, at different pH values are measured. By utilizing optical coherence tomography (OCT) and infrared (IR) spectroscopy we have directly measured physical changes in SC proteins and lipids. Our results indicate that SC swelling, which reflects alterations to SC structural proteins, is increased significantly at pH 10, compared to pH 4 and 6.5. The transition temperature (Tm) of SC lipids is found to increase at pH 10, compared to pH 4 and 6.5, suggesting a more rigid SC lipid matrix. Surfactants cause a further increase in swelling and lipid rigidity. Some aspects of what these results mean for SC physical properties as well as their implications to potential mechanisms of surfactant-induced skin irritation are discussed. Résumé Les compositions nettoyantes pour la peau à base d'alkyl carboxylates (savons) ont un potentiel irritant supérieur à celles à base de syndet tensioactifs tels que les alkyl isothionates ou les alkyl ether sulfates. Les facteurs en cause comprennent les différences de potentiel irritant inhérentes aux savons et aux syndet tensioactifs, les modifications de la chimie de la solution de tensioactif dues aux pH, et les effets directs du pH sur les propriétés physiques de la couche cornée (CC). Les travaux antérieurs n'ont pas traité directement l'effet du pH de la solution sur la couche cornée elle-même et son rôle potentiel dans l'irritation de la peau due à la solution nettoyante. Dans la présente étude on a mesuré les altérations des propriétés de la CC causées par des solutions à pH tamponné et deux tensioactifs fortement ionisables, le dodecyl sulfate de sodium et le lauryl ether sulfate de sodium, à différentes valeurs de pH. En utilisant la tomographie optique (OCT) et la spectroscopie à infrarouge (IR) on a mesuré directement les modifications physiques des protéines et des lipides de la CC. Nos résultats montrent que le gonflement de la CC, qui traduit des altérations des protéines structurales de la CC, augmente significativement à pH 10, par comparaison au pH 4 et 6.5. On observe que la température de transition (Tm) des lipides de la CC augmente à pH 10, par comparaison au pH 4 et 6.5, suggérant une matrice lipidique de la CC plus rigide. Les tensioactifs provoquent une augmentation plus importante du gonflement et de la rigidité lipidique. On aborde certains aspects de la signification de ces résultats vis-à-vis des propriétés physiques de la couche cornée ainsi que leurs conséquences sur les mécanismes potentiels de l'irritation de la peau causée par les tensioactifs. [source]


From collagen chemistry towards cell therapy , a personal journey

INTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 4 2007
Michael E. Grant
Summary The Fell,Muir Award requires the recipient to deliver a lecture and a review manuscript which provides a personal overview of significant scientific developments in the field of matrix biology over the period of the recipient's career. In this context, this review considers the collagen family of structural proteins and the advances in biochemical, molecular biological and genetic techniques which led to the elucidation of the structure, synthesis and function of this important group of extracellular matrix constituents. Particular attention is focussed on early research on the identification and assembly of the soluble precursors of collagen types I and II, and the identification of the precursor of basement membrane collagen type IV. In subsequent studies investigating the maintenance of the chick chondrocyte phenotype in culture, the influence of the extracellular milieu was found to influence markedly both cell morphology and collagen gene expression. These studies led to the discovery of collagen type X whose expression is restricted to hypertrophic chondrocytes at sites of endochondral ossification. Such research provided a prelude to investigations of mammalian endochondral ossification which is known to be aberrant in a variety of human chondrodysplasias and is reactivated in bone fracture repair and in osteoarthritis. The cloning of bovine and then human collagen type X genes facilitated studies in relevant human diseases and contributed to the discovery of mutations in the COL10A1 gene in families with metaphyseal chondrodysplasia type Schmid. Clustering of mutations in the C-terminal domain of the type X collagen molecule has now been widely documented and investigations of the pathogenic mechanisms in animal models are beginning to suggest the prospect of novel treatment strategies. [source]


Clear strategy screens for macromolecular crystallization

JOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2001
Andrzej Marek Brzozowski
The development of high-throughput crystallography combined with the wealth of already accumulated information about protein crystallization properties requires constant revision of current crystallization screening procedures. Two complementary 6 × 4 matrix `clear strategy screens' (CSS) have been developed and tested on a number of previously non-crystallized proteins. The screens yielded diffraction-quality crystals of a wide range of proteins (enzymes, transcription factors, structural proteins, etc.) in cases where the applications of commercially available screens were unsuccessful. Both their inherently simple design and their flexible nature provide an experimenter with a logical platform for further modification and optimization. Furthermore, the screens facilitate cryoprotection and potential incorporation of anomalous scatterers for multiple/single-wavelength anomalous dispersion (MAD/SAD) experiments. [source]


Cellular/intramuscular myxoma and grade I myxofibrosarcoma are characterized by distinct genetic alterations and specific composition of their extracellular matrix

JOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 7 2009
Stefan M. Willems
Abstract Cellular myxoma and grade I myxofibrosarcoma are mesenchymal tumours that are characterized by their abundant myxoid extracellular matrix (ECM). Despite their histological overlap, they differ clinically. Diagnosis is therefore difficult though important. We investigated their (cyto) genetics and ECM. GNAS1 -activating mutations have been described in intramuscular myxoma, and lead to downstream activation of cFos. KRAS and TP53 mutations are commonly involved in sarcomagenesis whereby KRAS subsequently activates c-Fos. A well-documented series of intramuscular myxoma (three typical cases and seven cases of the more challenging cellular variant) and grade I myxofibrosarcoma (n= 10) cases were karyotyped, analyzed for GNAS1, KRAS and TP53 mutations and downstream activation of c-Fos mRNA and protein expression. ECM was studied by liquid chromatography mass spectrometry and expression of proteins identified was validated by immunohistochemistry and qPCR. Grade I myxofibrosarcoma showed variable, non-specific cyto-genetic aberrations in 83,5% of cases (n= 6) whereas karyotypes of intramuscular myxoma were all normal (n= 7). GNAS1 -activating mutations were exclusively found in 50% of intramuscular myxoma. Both tumour types showed over-expression of c-Fos mRNA and protein. No mutations in KRAS codon 12/13 or in TP53 were detected. Liquid chromatography mass spectrometry revealed structural proteins (collagen types I, VI, XII, XIV and decorin) in grade I myxofibrosarcoma lacking in intramuscular myxoma. This was confirmed by immunohistochemistry and qPCR. Intramuscular/cellular myxoma and grade I myxofibrosarcoma show different molecular genetic aberrations and different composition of their ECM that probably contribute to their diverse clinical behaviour. GNAS1 mutation analysis can be helpful to distinguish intramuscular myxoma from grade I myxofibrosarcoma in selected cases. [source]


PEDF from mouse mesenchymal stem cell secretome attracts fibroblasts

JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 5 2008
Harshini Sarojini
Abstract Conditioned medium (secretome) derived from an enriched stem cell culture stimulates chemotaxis of human fibroblasts. These cells are classified as multipotent murine mesenchymal stromal cells (mMSC) by immunochemical analysis of marker proteins. Proteomic analysis of mMSC secretome identifies nineteen secreted proteins, including extracellular matrix structural proteins, collagen processing enzymes, pigment epithelium-derived factor (PEDF) and cystatin C. Immunodepletion and reconstitution experiments show that PEDF is the predominant fibroblast chemoattractant in the conditioned medium, and immunofluorescence microscopy shows strong staining for PEDF in the cytoplasm, at the cell surface, and in intercellular space between mMSCs. This stimulatory effect of PEDF on fibroblast chemotaxis is in contrast to the PEDF-mediated inhibition of endothelial cell migration, reported previously. These differential functional effects of PEDF toward fibroblasts and endothelial cells may serve to program an ordered temporal sequence of scaffold building followed by angiogenesis during wound healing. J. Cell. Biochem. 104: 1793,1802, 2008. © 2008 Wiley-Liss, Inc. [source]


Prevalence of erythrovirus genotypes in the myocardium of patients with dilated cardiomyopathy,

JOURNAL OF MEDICAL VIROLOGY, Issue 7 2008
U. Kühl
Abstract Parvovirus B19 (PVB19) is a member of the human erythrovirus family detected frequently in endomyocardial biopsies from patients with dilated cardiomyopathy. Human erythroviruses cluster into three genotypes 1,3 which share a high degree of homology between major structural proteins and may cause indistinguishable infections clinically and serologically. In human cardiac tissue erythrovirus genotypes other than PVB19 have not yet been reported. Three hundred seventeen consecutive patients with symptomatic dilated cardiomyopathy (median left ventricular ejection fraction: 28.6%, range 5,45%) who underwent endomyocardial biopsy for the elucidation of the etiology, were analyzed using a new consensus PCR assay designed for the detection of the three erythrovirus genotype sequences. Endomyocardial biopsies of 151 (47.6%) patients were erythrovirus-positive. Genotype 1 specific sequences were detected in 43/151 (28.5%) of positive biopsy samples, whereas genotype 2-specific sequences so far considered rare in human disease and not yet been described in human heart tissue was identified in 108/151 (71.5%) of virus-positive endomyocardial biopsies with a preference in patients above 50 years of age. In spite of younger age, systolic left ventricular dysfunction of genotype 1-positive patients was significantly reduced as compared to genotype 2-positive patients (24.4,±,10.4% vs. 31.0,±,9.5%, P,=,0.0001) at the initial presentation. The data show that two genetically distinct erythrovirus variants with a different age distribution are detectable in endomyocardial biopsies of patients with dilated cardiomyopathy. The erythrovirus genotype 2, not described previously in human heart tissue, is highly prevalent in the heart but the less prevalent genotype 1 is associated with more severe disturbed cardiac function. J. Med. Virol. 80: 1243,1251, 2008. © 2008 Wiley-Liss, Inc. [source]


Sequence analysis of genes encoding structural and nonstructural proteins of a human group B rotavirus detected in Calcutta, India

JOURNAL OF MEDICAL VIROLOGY, Issue 4 2001
Nobumichi Kobayashi
Abstract Nucleotide sequences of RNA segments encoding structural proteins(VP4, VP6, and VP7) and nonstructural proteins(NSP1 and NSP3) of a human group B rotavirus CAL-1, which was detected in Calcutta, India, were determined and their relatedness with cognate genes of other group B rotaviruses was analyzed. The CAL-1 genes showed generally high sequence identities (more than 90%) to those of human group B rotavirus, adult diarrheal rotavirus (ADRV) in China, while identities with bovine, murine, and ovine viruses were considerably lower (58,73%). Among RNA segments analyzed, sequence identity of the VP6 gene was relatively high compared with other gene segments. In the CAL-1 VP7 sequence, many characteristics were shared by ADRV, but not by other animal group B rotaviruses. In contrast, VP4 and NSP3 of CAL-1 were single animo acid and 23 amino acids longer than those of ADRV strain, respectively, due to differences of a few nucleotides. These findings suggested that human group B rotaviruses CAL-1 and ADRV might have originated from a common ancestral virus distinct from animal group B rotaviruses reported so far, while some notable sequence differences indicated the distinct nature of these viruses. J. Med. Virol. 64:583,588, 2001. © 2001 Wiley-Liss, Inc. [source]