Evidence for the glycoprotein nature of the cell sheath of Methanosaeta-like cells in the culture of Methanothrix soehngenii strain FE

1990 ◽  
Vol 36 (9) ◽  
pp. 631-636 ◽  
Author(s):  
Patrice Pellerin ◽  
Bernard Fournet ◽  
Philippe Debeire

The resilient of Methanothrix soehngenii strain FE was isolated. It contained carbohydrates (7%), mainly rhamnose, ribose, and fucose, which could be specifically liberated by alkaline hydrolysis or hydrazinolysis. Four oligosaccharide-containing fractions were separated; the two major fractions corresponded to large glycans composed of 15–30 residues. The whole sheath preparation was soluble in anhydrous hydrazine. A mild hydrazinolysis treatment led to a water-soluble glycoprotein fraction, which represented 60% of the starting material and contained 100% of the carbohydrates. These high molecular mass (> 500 kDa) glycoproteins were sensitive to pronase. Fast atom bombardment mass spectrometry analysis of the major glycopeptide fraction obtained after hydrogen fluoride treatment was in accordance with the presence of asparaginyl-rhamnose linkages on a Asn-X-Ser glycosylation site. This type of glycosidic linkage has been described previously in the surface layer of Bacillus stearothermophilus. Key words: Methanothrix soehngenii, Methanosaeta concilii, archaebacteria, bacterial glycoprotein, proteic sheath, asparaginyl-rhamnose.

1985 ◽  
Vol 260 (27) ◽  
pp. 14556-14563 ◽  
Author(s):  
J Thurin ◽  
M Herlyn ◽  
O Hindsgaul ◽  
N Strömberg ◽  
K A Karlsson ◽  
...  

Blood ◽  
1989 ◽  
Vol 73 (5) ◽  
pp. 1331-1339 ◽  
Author(s):  
MN Fukuda ◽  
KA Masri ◽  
A Dell ◽  
EJ Thonar ◽  
G Klier ◽  
...  

Abstract Congenital dyserythropoietic anemia type II (CDA II) or HEMPAS is a genetic disease caused by plasma membrane abnormality. The enzymic defect of HEMPAS has been suggested to be the lowered activity of N- acetylglucosaminyltransferase II, resulting in lack of polylactosamine formation on proteins and leading to accumulation of polylactosaminyl lipids. In contrast to typical HEMPAS cases, cell-surface labeling of the erythrocytes of a HEMPAS variant G.K. showed an absence of polylactosamines either on proteins or on lipids. Fast-atom bombardment mass spectrometry analysis of G.K.'s erythrocyte glycopeptides detected a series of high mannose-type oligosaccharides, which were not detected in erythrocyte N-glycans of normal cells or of other HEMPAS cases: The former contains polylactosaminoglycans and the latter contains hybrid- type oligosaccharides. Keratansulfate (sulfated polylactosamines) in this patient's serum was abnormally low. The galactosyltransferase activity in microsomal membranes prepared from G.K.'s mononucleated cells was 24% of the normal level, whereas this enzyme activity in G.K.'s serum was comparatively higher than normal. Western blotting of G.K.'s membranes using antigalactosyltransferase antibodies showed that G.K. has reduced amounts of this enzyme present. The results collectively suggest that variant G.K. is defective in polylactosamine synthesis owing to the decreased quantity of the membrane-bound form of galactosyltransferase.


2013 ◽  
Vol 288 (20) ◽  
pp. 14476-14487 ◽  
Author(s):  
Kevin D. Clark ◽  
Michael R. Strand

The phenoloxidase (PO) cascade regulates the melanization of blood (hemolymph) in insects and other arthropods. Most studies indicate that microbial elicitors activate the PO cascade, which results in processing of the zymogen PPO to PO. PO is then thought to oxidize tyrosine and o-diphenols to quinones, which leads to melanin. However, different lines of investigation raise questions as to whether these views are fully correct. Here we report that hemolymph from the silkmoth, Bombyx mori, rapidly melanizes after collection from a wound site. Prior studies indicated that in vitro activated PPO hydroxylates Tyr inefficiently. Measurement of in vivo substrate titers, however, suggested that Tyr was the only PO substrate initially present in B. mori plasma and that it is rapidly metabolized by PO. Fractionation of plasma by gel filtration chromatography followed by bioassays indicated that melanization activity was primarily associated with a high mass complex (∼670 kDa) that contained PO. The prophenoloxidase-activating protease inhibitor Egf1.0 blocked formation of this complex and Tyr metabolism, but the addition of phenylthiourea to plasma before fractionation enhanced complex formation and Tyr metabolism. Mass spectrometry analysis indicated that the complex contained PO plus other proteins. Taken together, our results indicate that wounding alone activates the PO cascade in B. mori. They also suggest that complex formation is required for efficient use of Tyr as a substrate.


Blood ◽  
1989 ◽  
Vol 73 (5) ◽  
pp. 1331-1339
Author(s):  
MN Fukuda ◽  
KA Masri ◽  
A Dell ◽  
EJ Thonar ◽  
G Klier ◽  
...  

Congenital dyserythropoietic anemia type II (CDA II) or HEMPAS is a genetic disease caused by plasma membrane abnormality. The enzymic defect of HEMPAS has been suggested to be the lowered activity of N- acetylglucosaminyltransferase II, resulting in lack of polylactosamine formation on proteins and leading to accumulation of polylactosaminyl lipids. In contrast to typical HEMPAS cases, cell-surface labeling of the erythrocytes of a HEMPAS variant G.K. showed an absence of polylactosamines either on proteins or on lipids. Fast-atom bombardment mass spectrometry analysis of G.K.'s erythrocyte glycopeptides detected a series of high mannose-type oligosaccharides, which were not detected in erythrocyte N-glycans of normal cells or of other HEMPAS cases: The former contains polylactosaminoglycans and the latter contains hybrid- type oligosaccharides. Keratansulfate (sulfated polylactosamines) in this patient's serum was abnormally low. The galactosyltransferase activity in microsomal membranes prepared from G.K.'s mononucleated cells was 24% of the normal level, whereas this enzyme activity in G.K.'s serum was comparatively higher than normal. Western blotting of G.K.'s membranes using antigalactosyltransferase antibodies showed that G.K. has reduced amounts of this enzyme present. The results collectively suggest that variant G.K. is defective in polylactosamine synthesis owing to the decreased quantity of the membrane-bound form of galactosyltransferase.


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