Immunohistochemical techniques for detection of dermatan sulfate proteoglycan in tissue sections

Dermatan sulfate proteoglycan chains were detected in tissue sections treated with chondroitin B-lyase (0.01 units/ml) in 20 mM Tris-HCl (pH 8.0) for 1 hr, followed by staining with antibody 9A2 specific for unsaturated uronic acid coupled to N-acetylgalactosamine-4 sulfate. In contrast, after treatment with chondroitin B-lyase, no positive staining was observed with antibodies 3B3 and 1B5 which react to the unsaturated uronic acid coupled to N-acetylgalactosamine 6-sulfate and unsaturated uronic acid coupled to N-acetylgalactosamine, respectively. The distribution of dermatan sulfate thus revealed was confirmed by comparison with that found by monoclonal antibody 6B6 which reacts with small proteoglycans carrying dermatan sulfate side chains. The localization of positive staining in fibrous connective tissues was almost identical with these two procedures.     

Comparison of the regional distribution of calspectin (nonerythroid spectrin or fodrin), alpha-actinin, vinculin nonerythroid protein 4.1, and calpactin in normal and avian sarcoma virus- or Rous sarcoma virus-induced transformed cells

With fluorescence and interference reflection microscopy (IRM), we compared the regional distribution of calspectin, its interacting proteins (nonerythroid protein 4.1 and calpactin), alpha-actinin, and vinculin in NRK cells and their avian sarcoma virus (ASV)- or temperature-sensitive (ts) Rous sarcoma virus (RSV)-transformed cells. The localization of these cytoskeletal proteins was determined with the specific antibodies. In NRK cells, alpha-actinin and vinculin were concentrated at adhesion plaques. By contrast, calspectin was distributed throughout the cytoplasm, but not concentrated at adhesion plaques. In ASV- and ts RSV-transformed cells, all three cytoskeletal proteins were concentrated at dot structures representing cellular feet. Nonerythroid protein 4.1 and calpactin were diffusely distributed throughout the cytoplasm of NRK cells and their transformed counterparts. In the case of calpactin, a part of this protein was excluded near regions of the terminal ends of stress fibers. These two proteins did not show the restricted location at the dot structures of transformed cells. From these findings, it is apparent that the accumulation of calspectin into dot structures is a specific event for cell transformation induced by the src protein.     

Induction of Cytoplasmic Streaming and Movement of Chloroplast Induced by L-Histidine and its Derivatives in Leaves of Egeria densa

Rotational cytoplasmic streaming in leaves of Egeria densa wasinduced by light as well as by L-histidine (L-His). During bothtreatement with light and with L-His chloroplasts on the periclinalface were dislodged and moved to the anticlinal face where rotationalcytoplasmic streaming occurred. The effective concentrationof L-His was about 0.01 mM and the effect was almost saturatedat 0.1 mM. A derivative of L-His, 3-methyl-L-histidine, wasslightly less effective than L-His. By contrast, 1-methyl-L-histidinewas almost ineffective for induction of streaming, not onlyin Egeria but also in Vallisneria. Our resutlts are in markedcontrast to Fitting's result (1936) that 1-M-L-His is more effectivethan L-His. In Egeria, 1-methyl-L-His counteracted the stimulativeeffect of L-His. 1-Methyl-L-His penetrated into leaf cells ofEgeria to the same extent as 3-methyl-L-His and to a greaterextent than L-His. This observation excludes the possibilitythat the impermeability of leaves to 1-M-L-His might be responsiblefor its ineffectiveness. 1-M-L-His did not interfere with photodinesis.Differences in the mechanism of induction of rotational streamingby L-His and by light are discussed. ⁴ Present address: Fukui Institute of Technology, Gakuen, Fukui,910 Japan (Received July 16, 1990; Accepted December 20, 1990)     

Immunochemical evidence that myosin I heavy chain-like protein is identical to the 110-kilodalton brush-border protein

In a previous study, we identified a new mammalian myosin heavy chain, termed myosin I heavy chain-like protein (MIHC), by molecular cloning of a bovine intestinal cDNA clone. In this investigation, we examined the relationship between MIHC and the 110-kDa intestinal brush-border protein, which possesses a myosin-like ATPase activity. We raised antibodies against a chemically synthesized oligopeptide representing a part of the MIHC sequence. These antibodies reacted specifically in immunoblots with the 110-kDa protein in both purified 110-kDa protein-calmodulin complex and crude microvillar protein extracts. Staining of tissue sections with these antibodies was specifically localized to the brush-border microvilli of small intestines, indicating an identical cellular localization for both MIHC and the 110-kDa protein. Furthermore, analysis of the MIHC sequence revealed two putative calmodulin-binding sites, which is consistent with the fact that the 110-kDa protein forms a complex with calmodulin. These results strongly support the conclusion that MIHC is identical to the 110-kDa protein and suggest that not only the conventional myosin system but also the MIHC (110-kDa protein)-calmodulin complex may play an important role in ATP-dependent and Ca2+-induced brush-border contraction.     

Solubilization and partial purification of protein kinase systems from brain membranes that phosphorylate calspectin: A spectrin-like calmodulin-binding protein (fodrin)

In brain tissue a spectrin-like calmodulin-binding protein calspectin, or fodrin, is concentrated in a synaptosome fraction, where most of the calspectin is associated with the synaptic membranes. This endogenous calspectin was phosphorylated by protein kinase system(s) associated with the membranes. Here, we report the solubilization and partial purification of the membrane-associated calspectin kinase activity. The activity was resolved on a gel filtration column into two fractions, peaks I and II having estimated M_r of 800 000 and 88 000. The activity of peak I was dependent on the presence of both Ca²⁺ and calmodulin. Peak II revealed a basal activity in the absence of Ca²⁺ and calmodulin, which was stimulated 2-fold by addition of Ca²⁺. Calmodulin had no effect on the peak II activity.     

Purification and Some Properties of Lignostilbene-a,/i-dioxygenase Responsible for the Ca—Cp Cleavage of a Diarylpropane Type Lignin Model Compound from Pseudomonas sp. TMY1009

A novel dioxygenase, lignostilbene-a,β-dioxygenase (LSD), which catalyzes cleavage of the interphenyl double bond of lignin-derived stilbenes, was isolated. Four isozymes of LSD were separated from cell-free extracts of Pseudomonas sp. TMY1009 by ion-exchange chromatography on a DEAE- Toyopearl column. The major isozyme, LSD-I, was purified to electrophoretic homogeneity and characterized.

LSD-I cleaved the interphenyl double bond of l,2-bis(4′-hydroxy-3′-methoxyphenyl)ethylene with the optimum pH at 8.5. The Km of LSD-I was 11 μm for the stilbene and 110/iM for oxygen. The molecular weight of LSD-I, which is composed of two identical subunits, was estimated to be 94,000. LSD-I contained 1 g atom of iron per 1 mol of enzyme protein.     

Early-stage vegetation recovery in forests damaged by oak wilt disease and deer browsing: effects of deer-proof fencing and clear-cutting

Landscape and Ecological Engineering - Oak wilt disease and deer browsing have depleted the canopy and forest floor of secondary Quercus serrata and Quercus variabilis forests in Japan. Small-scale...     

Disulfide bond mediates aggregation, toxicity, and ubiquitylation of familial amyotrophic lateral sclerosis-linked mutant SOD1

Mutations in the Cu/Zn-superoxide dismutase (SOD1) gene cause familial amyotrophic lateral sclerosis (ALS) through the gain of a toxic function; however, the nature of this toxic function remains largely unknown. Ubiquitylated aggregates of mutant SOD1 proteins in affected brain lesions are pathological hallmarks of the disease and are suggested to be involved in several proposed mechanisms of motor neuron death. Recent studies suggest that mutant SOD1 readily forms an incorrect disulfide bond upon mild oxidative stress in vitro, and the insoluble SOD1 aggregates in spinal cord of ALS model mice contain multimers cross-linked via intermolecular disulfide bonds. Here we show that a non-physiological intermolecular disulfide bond between cysteines at positions 6 and 111 of mutant SOD1 is important for high molecular weight aggregate formation, ubiquitylation, and neurotoxicity, all of which were dramatically reduced when the pertinent cysteines were replaced in mutant SOD1 expressed in Neuro-2a cells. Dorfin is a ubiquityl ligase that specifically binds familial ALS-linked mutant SOD1 and ubiquitylates it, thereby promoting its degradation. We found that Dorfin ubiquitylated mutant SOD1 by recognizing the Cys(6)- and Cys(111)-disulfide cross-linked form and targeted it for proteasomal degradation.