Processing and rheological behavior of cross‐linked polyethylene containing disulfide bonds

Cryo-electron microscopy of two-dimensional crystals of reduced type B botulinum neurotoxin

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100123052 ◽

1992 ◽

Vol 50 (1) ◽

pp. 530-531

Author(s):

P. F. Flicker ◽

V.S. Kulkarni ◽

J. P. Robinson ◽

G. Stubbs ◽

B. R. DasGupta

Keyword(s):

Disulfide Bonds ◽

Clostridium Botulinum ◽

Structural Changes ◽

Two Dimensional ◽

Type B ◽

Single Chain ◽

Muscle Paralysis ◽

Cryo Electron Microscopy ◽

Disulfide Linkages ◽

Intracellular Action

Botulinum toxin is a potent neurotoxin produced by Clostridium botulinum. The toxin inhibits release of neurotransmitter, causing muscle paralysis. There are several serotypes, A to G, all of molecular weight about 150,000. The protein exists as a single chain or or as two chains, with two disulfide linkages. In a recent investigation on intracellular action of neurotoxins it was reported that type B neurotoxin can inhibit the release of Ca++-activated [3H] norepinephrine only if the disulfide bonds are reduced. In order to investigate possible structural changes in the toxin upon reduction of the disulfide bonds, we have prepared two-dimensional crystals of reduced type B neurotoxin. These two-dimensional crystals will be compared with those of the native (unreduced) type B toxin.

Download Full-text

Specific Cross-reaction of IgG Anti-phospholipid Antibody with Platelet Glycoprotein IIIa

Thrombosis and Haemostasis ◽

10.1055/s-0038-1650238 ◽

1996 ◽

Vol 75 (01) ◽

pp. 168-174 ◽

Cited By ~ 13

Author(s):

Shigeru Tokita ◽

Morio Arai ◽

Naomasa Yamamoto ◽

Yasuhiro Katagiri ◽

Kenjiro Tanoue ◽

...

Keyword(s):

Platelet Aggregation ◽

Heparan Sulfate ◽

Disulfide Bonds ◽

Dextran Sulfate ◽

Human Platelets ◽

Platelet Glycoprotein ◽

Activated Platelets ◽

Fibrinogen Binding ◽

Dose Dependent Fashion ◽

Glycoprotein Iiia

SummaryTo study the pathological functions of anti-phospholipid (anti-PL) antibodies, we have analyzed their effect on platelet function. We identified an IgG anti-PL mAb, designated PSG3, which cross-reacted specifically with glycoprotein (GP) IIIa in human platelets and inhibited platelet aggregation. PSG3 bound also to certain polyanionic substances, such as double-stranded DNA, heparan sulfate, dextran sulfate and acetylated-LDL, but not to other polyanionic substances. The binding of PSG3 to GPIIIa was completely inhibited by heparan sulfate and dextran sulfate, indicating that PSG3 recognizes a particular array of negative charges expressed on both GPIIIa and the specified polyanionic substances. Since neither neuraminidase- nor endoglycopeptidase F-treatment of GPIIIa had any significant effect on the binding of PSG3, this array must be located within the amino acid sequence of GPIIIa but not in the carbohydrate moiety. Reduction of the disulfide bonds in GPIIIa greatly reduced its reactivity, suggesting that the negative charges in the epitope are arranged in a particular conformation. PSG3 inhibited platelet aggregation induced by either ADP or collagen, it also inhibited fibrinogen binding to activated platelets in a dose-dependent fashion. PSG3, however, did not inhibit the binding of GRGDSP peptide to activated platelets. These results suggest that the PSG3 epitope on GPIIIa contains a particular array of negative charges, and possibly affects the fibrinogen binding to GPIIb/IIIa complex necessary for platelet aggregation.

Download Full-text

From biorefineries to bioproducts: conversion of pretreated pulp from biorefining streams to lignocellulose nanofibers

TAPPI Journal ◽

10.32964/tj18.4.233 ◽

2019 ◽

Vol 18 (4) ◽

pp. 233-241

Author(s):

CHENGGUI SUN ◽

RICHARD CHANDRA ◽

YAMAN BOLUK

Keyword(s):

Energy Consumption ◽

Enzymatic Hydrolysis ◽

Rheological Behavior ◽

Material Basis ◽

Softwood Pulp ◽

Energy Consumptions ◽

Hardwood Pulp ◽

The Stability ◽

Lignocellulose Nanofibers

This study investigates the use of pretreatment and enzymatic hydrolysis side streams and conversion to lignocellulose nanofibers. We used a steam-exploded and partial enzymatic hydrolyzed hardwood pulp and an organosolv pretreated softwood pulp to prepare lignocellulose nanofibers (LCNF) via microfluidization. The energies applied on fibrillation were estimated to examine the energy consumption levels of LCNF production. The energy consumptions of the fibrillation processes of the hardwood LCNF production and the softwood LCNF production were about 7040-14080 kWh/ton and 4640 kWh/ton on a dry material basis, respectively. The morphology and dimension of developed hardwood and softwood LCNFs and the stability and rheological behavior of their suspensions were investigated and are discussed.

Download Full-text