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PubMed1978

Ultrastructural identification of collagen and glycosaminoglycans in notochordal extracellular matrix in vivo and in vitro.

Notochordal extracellular matrix consists of a continuous basal lamina, amorphous materials and microfibrils embedded in the ground substance of low electron density. Together they comprise the notochord sheath and are of considerable interest because of their suspected role in early embryonic tissue interactions. The notochord is particularly well-suited to morphological investigation of extracellular matrix because it is one of the few embryonic epithelia which produces ultrastructurally recognizable stroma in vitro without the advantage of a collagenous substratum. Furthermore, these matrix components produced in vitro are morphologically identical to those observed in vivo. The present study used ruthenium red staining to demonstrate that notochordal microfibrils exhibit collagen-like cross-banding patterns both in vivo and in vitro. Collagenase and testicular hyaluronidase digestion studies designed to localize collagen and glycosaminoglycans show a reduction of microfibrillar diameters by 30-35%. Furthermore, these enzyme treatments frequently result in enhanced striations of microfibrils. When cis-hydroxyproline (a proline analog) or beta-aminoproprionitrile (BAPN, a lathyrogenic compound) is added to the culture medium, a similar reduction in microfibrillar diameters is seen. Moreover, increased ruthenium red-positive surface coats and large collagen fibrils are frequently present in BAPN-treated cultures, implying a stimulatory metabolic effect. We conclude that most, if not all, notochordal extracellular matrix components are composed of both collagen and glycosaminoglycans and suggest that the entire extracellular matrix should be considered a macromolecular composite which acts in concert to induce or stabilize developmental interactions.

Aminopropionitrile↗
PubMed2000

A transmission electron microscope study using vitrified ice sections of predentin: structural changes in the dentin collagenous matrix prior to mineralization.

The assembly of the collagenous organic matrix prior to mineralization is a key step in the formation of bones and teeth. This process was studied in the predentin of continuously forming rat incisors, using unstained vitrified ice sections examined in the transmission electron microscope. Progressing from the odontoblast surface to the mineralization front, the collagen fibrils thicken to ultimately form a dense network, and their repeat D-spacings and banding patterns vary. Using immunolocalization, the most abundant noncollagenous protein in dentin, phosphophoryn, was mapped to the boundaries between the gap and overlap zones along the fibrils nearest the mineralization front. It thus appears that the premineralized collagen matrix undergoes dynamic changes in its structure. These may be mediated by the addition and interaction with the highly anionic noncollagenous proteins associated with collagen. These changes presumably create a collagenous framework that is able to mineralize.

Animals↗
PubMed1998

Matrix metalloproteinase-mediated extracellular matrix protein degradation in human pulmonary emphysema.

The aim of this study was to investigate the extracellular degrading proteolytic cascade proteins referred to as matrix metalloproteinase-1 (MMP-1), MMP-2, MMP-9, membrane-type matrix metalloproteinase-1 (MT1-MMP), tissue inhibitors of matrix metalloproteinase-1 (TIMP-1), TIMP-2, neutrophil elastase, and alpha1-antitrypsin in human pulmonary emphysema. Localization of MMP-1, MMP-2, MMP-8, MMP-9, MT1-MMP, TIMP-1, and TIMP-2 was verified by immunohistochemical analysis. The results of our study indicated that the immunoreactivity of MMP-1, MMP-8, MMP-9, and TIMP-1 was absent, whereas MT1-MMP and MMP-2 were mainly observed in pneumocytes, fibroblasts, and alveolar macrophages. Although MT1-MMP and MMP-2 were observed both in emphysematous and normal lung tissue, these immunoreactivities were intense in the emphysematous samples. The presence of MMP-1, MMP-2, MMP-9, TIMP-1, and TIMP-2 was confirmed at mRNA level by reverse transcription-PCR analysis and enzyme immunoassay (EIA). However, the only statistical difference that was observed was in MMP-2 and MMP-9 (MMP-2: emphysematous samples, 19.1+/-2.1 versus control samples, 5.2+/-0.60 microg/g protein, p < 0.05; MMP-9: emphysematous samples, 18.4+/-5.6 versus control samples, 8.1+/-2.7 microg/g protein, p < 0.05). Results of the neutrophil elastase as analyzed by EIA, and alpha1-antitrypsin levels as detected by laser nephelometric immunoassay, indicated no statistical difference between the emphysematous and control groups. In addition to the presence of mRNA levels, the level of MT1-MMP according to immunoblot analysis increased in the emphysematous samples. Gelatin zymographic analysis confirmed the presence of both pro and active forms of MMP-2, and the increased ratio of the active form of MMP-2 in emphysematous samples (25.9%+/-2.0% versus 11.2%+/-3.3%, p < 0.05), indicated in situ activation of MMP-2 by MT1-MMP. Elastin zymographic analysis showed elastolytic activity by MMP-2 and MMP-9 but not the reported band of macrophage metalloelastase (MMP-12). The data suggest that the MT1-MMP/MMP-2/TIMP-2 system plays a significant role in the MMP-mediated extracellular matrix degradation and tissue remodeling of emphysematous lungs, and thus may contribute to the weakening of lung parenchyma and lead to the formation of emphysema.

Aged↗
PubMed1992

Bovine serum amine oxidase: half-site reactivity with phenylhydrazine, semicarbazide, and aromatic hydrazides.

Aromatic hydrazides of the general formula NH2NHCO(CH2)nC6H4R were covalently bound by bovine serum amine oxidase (BSAO), giving rise to optical and CD absorptions at 350-400 nm. Benzohydrazides (n = 0) reacted slowly, in the ratio of one per dimeric protein molecule, like semicarbazide. Phenylacetohydrazides (n = 1) and phenylpropionic hydrazides (n = 2) reacted instead in the ratio of two per dimer, one molecule at a much faster rate than the other. The fast reaction correlated with the loss of enzymatic activity. The contribution to the optical absorbance of either molecule was identical, but only the first one produced a CD band, the wavelength and sign of which were determined by the number n of methylene groups in the hydrazide. In n = 1 and n = 2 compounds, the reaction was faster as the R substituent became more hydrophobic (triazolyl less than imidazolyl less than phenyl), suggesting a specific interaction with the protein matrix. Phenylhydrazine was found to react with the native enzyme in the ratio of only one per protein dimer. However, one phenylhydrazine was also slowly bound by most 1:1 enzyme-hydrazide adducts, with the formation of ternary derivatives. Phenylhydrazine formed the usual intense band at 447 nm with n = 1 and n = 2 hydrazide-BSAO adducts and a weaker, blue-shifted band with the adducts of semicarbazide and of some n = 0 hydrazides. In both cases, the hydrazide absorption band was unaffected. Competition was observed with other benzohydrazides and with the second molecule of n = 1 compounds. A half-site mechanism appears to be operative, the second site being always less reactive than the first. Reactivity and adduct conformation were also affected by N,N-diethyldithiocarbamate, a powerful enzyme inhibitor that binds copper.

Amine Oxidase (Copper-Containing)↗
PubMed2006

Laser spectroscopy of NiBr: new electronic states and hyperfine structure.

Laser induced fluorescence spectrum of NiBr in the visible region between 604 and 666 nm has been recorded and analyzed. Fourteen bands belonging to three electronic transition systems, namely, [15.1] (2)Delta(52)-X (2)Pi(32), [15.1] (2)Pi(32)-X (2)Pi(32), and [14.0] (2)Delta(52)-X (2)Pi(32) have been observed. Spectra of isotopic molecules were also observed and analyzed. Detailed analysis of the recorded spectra indicated that the two electronic states [15.1] (2)Pi(32) and [15.1] (2)Delta(52) lie about 1 cm(-1) apart from each other and J-dependent perturbation due to spin-uncoupling interaction has been observed. Least squares fitting procedures involving deperturbation matrix elements were used to fit the observed line positions, which yielded accurate molecular constants for the [15.1] (2)Pi(32) and [15.1] (2)Delta(52) states. In addition, the (1,0) band of the [15.1] (2)Delta(52)-X (2)Pi(32) transition shows partially resolved hyperfine structure that was caused by the interaction of unpaired electron with the magnetic moment of the Br nucleus (nuclear spin of I=32) in the excited state. The rapid decrease in hyperfine width as J increases suggests that the hyperfine coupling in the excited state conforms to Hund's case (a(beta)) coupling scheme.

Journal Article↗
PubMed1995

Novel 3,4-di- and 3,4,5-trihydroxyphenylalanine-containing polypeptides from the blood cells of the ascidians Ascidia ceratodes and Molgula manhattensis.

Acetic acid urea extraction of the blood cells of two ascidian species yielded four novel families of polypeptides (3500-5300 Da) containing 3,4-dihydroxyphenylalanine (DOPA) and 3,4,5-trihydroxyphenylalanine (TOPA) from the Phlebobranch Ascidia ceratodes and two DOPA proteins (9-10 kDa) from the Stolidobranch Molgula manhattensis. 3,4,5-Trihydroxyphenylalanine residues have not been found previously in polypeptides in any biological system. The DOPA content of the M. manhattensis proteins is the highest yet reported for a naturally occurring DOPA protein. The successful isolation of proteinaceous components from A. ceratodes blood cells requires the incorporation of high concentrations of complexing agent in the extraction buffers to inactivate vanadium(III) which forms intractable organometallic polymers. The A. ceratodes blood cell polypeptides are all rich in alanine and TOPA residues, have neutral to basic pI values, and, while all give single bands on acid urea-polyacrylamide electrophoresis, they exhibit extensive microheterogeneity. This is reflected by their large molecular weight distribution as determined by matrix-assisted laser desorption ionization-mass spectrometry, the variation in the ratio of their 280-nm absorption to chromophores of unknown structure in the polypeptide's electronic absorption spectra, and the N-terminal sequence analysis. The two M. manhattensis proteins consist largely of four amino acids (alanine, valine, phenylalanine, and DOPA) with DOPA accounting for upward of 40 mol%. Both give an N-terminus of Ala-Phe-Tyr before resisting further progress by Edman degradation. Proteins and polypeptides from both ascidians are extremely resistant to proteases, a property which, while hampering characterization by sequence analysis, appears ideally suited to their proposed function of forming an impervious hemostat at the site of vascular injury. The yield of proteins and polypeptides relative to tunichromes appears to be seasonally dependent. The presence of DOPA and TOPA moieties in the proteins and polypeptides implicates them, as well as the tunichromes, as potential metal-sequestering agents.

Amino Acid Sequence↗
PubMed1995

Direct mass spectrometric analysis of glycosphingolipid transferred to a polyvinylidene difluoride membrane by thin-layer chromatography blotting.

A simple, rapid method for the analysis of glycosphingolipid that combines "thin-layer chromatography (TLC) blotting" and mass spectrometry is reported. Glycosphingolipids developed by TLC were transferred to a polyvinylidene difluoride membrane by TLC blotting, after which the glycosphingolipid band on the membrane was excised and placed on a mass spectrometer probe tip, and a few microliters of triethanolamine was added as the matrix. The sample was analyzed by secondary ion mass spectrometry. About 1 microgram of glycosphingolipid subjected to TLC can be analyzed. The major advantage of this method is that glycosphingolipid can be analyzed structurally without purification by repeated column chromatography.

Animals↗
PubMed2001

Molecular analysis of phylogenetic relationships among Myrmecophytic macaranga species (Euphorbiaceae).

Many species of the paleotropical pioneer tree genus Macaranga Thou. (Euphorbiaceae) live in association with ants. Various types of mutualistic interactions exist, ranging from the attraction of unspecific ant visitors to obligate myrmecophytism. In the latter, nesting space and food bodies are exchanged for protection by highly specific ant partners (mainly species of the myrmicine genus Crematogaster). As a first step toward elucidating the coevolution of ant-plant interactions in the Macaranga-Crematogaster system, we have initiated a molecular investigation of the plant partners' phylogeny. Nuclear ribosomal DNA internal transcribed spacer (ITS) sequences were analyzed for 73 accessions from 47 Macaranga species, representing 17 sections or informally described species groups. Three accessions from the putative sister taxon Mallotus Lour, were included as outgroups. Cladograms of the ITS data revealed Macaranga to be nested within Mallotus. ITS sequences are highly similar within section Pachystemon s.str., suggesting a relatively recent and rapid radiation of obligate myrmecophytes within this section. Forty-three accessions, mainly of ant-inhabited species, were additionally investigated by random amplified polymorphic DNA (RAPD) and microsatellite-primed PCR (MP-PCR) techniques. Phenetic analysis of RAPD and MP-PCR banding profiles generally confirmed the ITS results. Best resolutions for individual clades were obtained when ITS and RAPD/MP-PCR data were combined into a single matrix and analyzed phenetically. The combined analysis suggests multiple (four) rather than a single evolutionary origin of myrmecophytism, at least one reversal from obligate myrmecophytism to nonmyrmecophytism, and one loss of mutualistic specifity.

DNA, Plant↗
PubMed1975

Electron microscopic and electron histochemical studies on embryonal rhabdomyosarcoma of the orbit.

A small number of differentiated tumor cells could be found besides a great number of undifferentiated ones. Abnormal dense granules were found in the nuclei of undifferentiated tumor cells, not in differentiated ones. Non-specific filaments were seen in the cytoplasm of undifferentiated tumor cells. Differentiated tumor cells demonstrated various stages of myofibrillar structures such as A, I, and Z bands, many glycogen granules, mitochondria and a basement membrane. Polyglucose particles synthesized from glycose-1-phosphate by phosphorylase activity were located in the cytoplasmic matrix of undifferentiated and differentiated tumor cells and in the karyolymph of undifferentiated tumor cells. Polyglucose partices increased in number according to the degree of differentiation of tumor cells.

Basement Membrane↗
PubMed1976

Ultrastructure and light microscope appearance of Blastocystis hominis in a patient with enteric disease.

The patient reported had a fulminant, refractory diarrhea of unknown etiology producing about 81 of diarrheal fluid daily which required continuously large volumes of intravenous fluid therapy. No protozoon other than Blastocystis hominis was present. Bacterial counts were very low in the fecal material because of continuous antibiotic therapy. Blastocystis hominis was present in large numbers, averaging for a 5-day period, 8.3 X 10(6)/ml of diarrheal fluid. Treatment with metronidazole for 12 days had no effect on either the diarrhea or the numbers of B. hominis present. The patient died from aspiration pneumonia without a firm diagnosis of his underlying disease. Identification of an unusual form of B. hominis seen only in diarrheal fluid was confirmed through cultivation, specific fluorescent antibody staining, as well as by transmission electron microscopy and light microscopy using hematoxylin staining and Nomarski interference contrast. The most significant result of this study is the description of ultrastructure of the in vivo trophozoite form of B. hominis. The persistence of certain morphologic features of the in vivo and in vitro forms of B. hominis is described. In vivo, B. hominis has a larger nucleus than in vitro, more prominent, well structured nucleoli, and hundreds of mitochondria with numerous delicate saccular cristae in a clear electron-lucent matrix and complex internal structure. Many cytoplasmic vesicles lined with ribosomes are present. The in vivo structure differs from the granular culture form of B. hominis, which has a smaller nucleus (nuclei), no distinct nucleoli, mitochondria characterized by a uniform structureless electron dense matrix, and few cytoplasmic, ribosome-lined vesicles. A feature retained in both in vivo and in vitro B. hominis is a distinct crescentic band of nuclear chromatin.

Diarrhea↗
PubMed1991

Immunohistochemical and immunochemical detection of a similar epitope in enamel proteins and monocyte-macrophage protein recognized by mouse monoclonal antibody MOMA-2.

These studies were made as a first step in elucidating unknown functions of enamel proteins in odontogenesis. The cytoplasm of ameloblasts and the proteins in dentine matrix before mineralization were stained with this monoclonal antibody. SDS-PAGE and Coomassie blue staining of proteins extracted from enamel showed several protein bands. Immunoblotting revealed that proteins recognized by this antibody were situated between 20-30 kDa. These results indicate that enamel proteins, presumably amelogenins, have an epitope resembling monocyte-macrophage protein. The findings suggest that epithelial-mesenchymal interaction in odontogenesis and preosteoblast-preosteoclast interaction in osteogenesis may be similar.

Ameloblasts↗
PubMed1992

Evidence for malonyl-CoA-sensitive carnitine acyl-CoA transferase activity in sarcoplasmic reticulum of canine heart.

The formation of palmitoylcarnitine is catalyzed by carnitine palmitoyl-transferase (CPT-I) and this catalysis is the first committed step in beta-oxidation. The malonyl-CoA-inhibited isoform appears to be distinct from latent (CPT-II) activity, which is localized to the matrix side of the mitochondrial inner membrane. Sarcoplasmic reticulum from canine cardiac muscle was fractionated on a discontinuous sucrose density gradient into three major bands, all of which contained Ca(2+)-ATPase activity. Only the fraction that banded at a concentration of 38% surcrose was slightly contaminated by mitochondria. Peroxisomal uricase was low or absent in fractionated SR. All sarcoplasmic reticulum fractions contained malonyl-CoA-sensitive medium- (COT) and long-chain (CPT) carnitine acyltransferase activities. CPT activity decreased in sarcoplasmic reticulum when Triton X-100 was present. Carnitine acyltransferase activities were inactivated by preincubating the sarcoplasmic reticulum with the sulfhydryl reagent, 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB). In contrast, mitochondrial CPT-II activity was stable in the presence of DTNB and activated by Triton X-100. Western blots of mitochondria and sarcoplasmic reticulum fractions showed that the mitochondrial fractions reacted with antibody to mitochondrial CPT-II but not with SR protein when both were added at comparable specific activities. The data suggest that cardiac SR contains a unique malonyl-CoA-sensitive isoform of CPT, and that synthesis of acylcarnitine may occur in the microenvironment of Ca2+ transport, where the extent of production of acylcarnitine is controlled by cardiac acetyl-CoA carboxylase activity.

Animals↗
PubMed1983

Purification and properties of a brain enzyme which deiminates proteins.

The deimination of guanidyl groups of peptides, proteins and other arginine-containing compounds is catalyzed by enzymes found in mammalian brain and epidermis. In cow, the brain and epidermal enzymes differ kinetically and physically, but both may be quantitated by measuring the production of benzoyl citrulline ethyl ester from benzoyl-arginine ethyl ester. The brain enzyme has been purified to apparent homogeneity, as judged by the presence of only one 85,000 dalton band in purified preparations when examined by SDS-polyacrylamide gel electrophoresis. An antibody raised to this band precipitates pure and partially purified brain enzyme but not partially purified epidermal enzyme, using the Ouchterlony technique. The antibody bound to an insoluble matrix removes brain enzyme activity from solution but not epidermal enzyme activity. The Km of the brain enzyme for benzoyl-arginine ethyl ester is about 0.33 mM.

Animals↗
PubMed2005

Form follows function: developmental and physiological view on ventricular myocardial architecture.

The arrangement of myocytes within the ventricle is critical for its contractile performance, as evidenced by significant functional impairment seen in cardiomyopathies associated with myofiber disarray or post-infarction remodeling. A review on this topic by Anderson and associates provides anatomical insight gained from a multitude of approaches, and concludes that the best concept is that of syncytial continuum with supporting collagenous matrix. The overall arrangement is in the form of several intertwined helices, and the authors find no support for a recently suggested ventricular myocardial band hypothesis. This commentary aims at providing a developmental and physiological perspective on this purely anatomical concept. Unlike some other organ systems, the developing heart has to function since very early stages to support the oxygen and nutrition demands of the growing embryo, thus putting some constraints on heart development. The ventricular myocardial architecture transforms from a single-layered tube through trabeculated stages into a mature form that relies on a multi-layered compact zone. The first evidence of helical patterns is found in trabeculated hearts during ventricular contraction, and layers with different helix pitch develop during later fetal stages as the compact zone thickens. The second major point determining ventricular contraction is the sequence of its electrical activation. The ventricular activation sequence changes concomitantly with its morphology, from slow peristaltoid through base-to-apex pattern found in looped trabeculated hearts, to mature apex-to-base direction. Thus, adult ventricular myocardial architecture is best understood when one also considers the way it developed together with its electrical activation sequence and contraction pattern.

Adult↗
PubMed2005

Structure and physical properties of ternary rare-earth cobalt bismuth intermetallics (RE)12Co5Bi (RE = Y, Gd, Tb, Dy, Ho, Er, Tm).

The rare-earth intermetallic compounds (RE)12Co5Bi (RE = Y, Gd, Tb, Dy, Ho, Er, Tm) were prepared by arc-melting and annealing at 600 degrees C. These compounds extend the previously known (RE)6M2+xX1-x (M = Co, Ni; X = Ga, In, Sn, Pb) series with the Ho6Co2Ga-type structure to X = Bi. The crystal structure of Ho12Co5Bi was refined by the Rietveld method from powder X-ray diffraction data obtained using synchrotron radiation (Pearson symbol oI36, orthorhombic, space group Immm, Z = 2, a = 9.37598(14) A, b = 9.37871(14) A, c = 9.85465(13) A). Unlike other Ho6Co2Ga-type compounds, the 2a site in Ho12Co5Bi is exclusively occupied by Co atoms. Four-probe electrical resistivity measurements on sintered polycrystalline samples of (RE)12Co5Bi indicated metallic behavior. Magnetic measurements revealed behavior ranging from frequency-dependent maxima in the ac susceptibility for Y12Co5Bi to possible ferrimagnetic ordering for Gd12Co5Bi to antiferromagnetic ordering with metamagnetic transitions for the remaining compounds. As confirmed by band structure calculations using Y12Co5Bi as a model compound, Y-Y and Y-Co interactions are the most important bonding components, but matrix effects are likely responsible for anomalously short Co-Co contacts in the structure.

Journal Article↗
PubMed1995

Co-occurrence of perineuronal nets with GABAA receptor alpha 1 subunit-immunoreactive neurones in the rat septal region.

The immunocytochemical demonstration of the GABAA receptor alpha 1 subunit was combined with the Wisteria floribunda agglutinin staining of lattice-like extracellular matrix components--known as perineuronal nets--in the rat basal forebrain. Both were found to be co-localized in the septal-diagonal band region (e.g. in the medial septum, 96%), but only exceptionally in the ventral pallidum (3-10%) and nowhere in other basal forebrain subdivisions. This co-occurrence of perineuronal nets with septo-hippocampal projection neurones--previously characterized as GABAergic--expressing the GABAA receptor alpha 1 subunit- as well as parvalbumin-immunoreactivity, suggests the involvement of these intra- and extraneuronal components in the fast spiking neuronal activity essential for the generation and maintenance of hippocampal theta rhythm.

Animals↗
PubMed2006

Intraschisis cavity fluid composition in congenital X-linked retinoschisis.

PURPOSE: To describe the intraschisis cavity protein composition in congenital X-linked retinoschisis (CXLRS) from two eyes of one child. METHODS: The authors present a child with complex, Type 3 CXLRS who underwent bilateral surgical repair with autologous plasmin enzyme-assisted lens-sparing vitrectomy. Undiluted samples of intraschisis fluid and vitreous fluid from two eyes (one child) were obtained and used for protein analysis. RESULTS: The patient underwent successful schisis repair with plasmin-assisted lens-sparing vitrectomy and silicone oil. Two unique protein bands were identified in the intraschisis cavity sample of each eye by gel electrophoresis. The proteins were identified as tenascin-C, an extracellular matrix protein involved in wound healing, and cystatin C, a ubiquitous cysteine protease inhibitor implicated in inflammation. CONCLUSIONS: Tenascin-C has previously been described in its complex relationship with decorin and fibronectin in normal wound healing. Tenascin's upregulation in sites of inflammation and tenascin's role as an antiadhesive molecule may contribute to the pathogenesis of CXLRS. To the authors' knowledge, this is the first description of intraschisis cavity fluid.

Biomarkers↗
PubMed1989

Red edge excitation effect in intact eye lens.

Shift in the wavelength of emission upon shift in the excitation wavelength towards the red edge of the absorption band is termed Red Edge Excitation Shift (REES). This effect is observed only in situation where the fluorophore mobility with respect to the surrounding matrix is considerably reduced. We have observed such red edge excitation effect in the intact eye lens. The REES observed for a normal lens is different from that seen in a photodamaged lens and hence appears to be a potential tool to monitor the changes in the state of the lens. Photodamage experiments with tryptophan in polyethylene glycol (PEG) and intact eye lens indicate that the red edge photon can also cause photodamage.

Animals↗