Sugar composition of biofilms produced by paper mill bacteria

Biofilms of paper mill bacteria were cultivated in paper mill white water-simulating conditions on glass slides or stainless steel coupons in a laboratory culture system. The sugar content and composition of the biofilms were analysed and compared with the sugar composition of paper mill slimes. Acid methanolysis followed by gas chromatography revealed that Burkholderia was the major biofilm producer in pure culture, producing up to 50 microg of biofilm sugar cm(-2) in 5 days in rich medium and 10 microg in paper mill simulating medium. A mixture of simulated paper mill water with a culture medium yielded more biofilm (100 microg cm(-2)) than either of the media alone, so the biofilm accumulation was not proportional to the available substrate. More biofilm accumulated on stainless steel coupons than on glass slides, and the steel-coupon biofilms contained slightly more uronic acids. The biofilm sugars contained mainly galactose, glucose, mannose, and rhamnose. In paper mill medium, the Burkholderia biofilm contained more galactose and glucose, and less rhamnose, than in rich laboratory medium. The sugar composition of paper mill slimes was quite similar to those of steel-cultured Burkholderia cepacia biofilms. This suggests that Burkholderia cepacia is responsible for much of the slime in the paper mill.     

Biosynthesis of the prohormone convertase mPC1 in AtT-20 cells.

A new family of mammalian subtilisin-like enzymes, probably involved in the processing of proproteins in regulated and constitutive cells at paired basic residues, has recently been discovered. Little information exists as yet concerning the biosynthesis of these endogenous subtilisin-like enzymes. In the present work the biosynthesis and release of the endogenous prohormone convertase PC1 in AtT-20 cells were studied. As predicted from mRNA studies, AtT-20 cells contain high levels of PC1 protein. Through immunoblotting, 87-kilodalton (kDa) and 66-kDa bands were detected with an amino terminally directed antiserum; however, only the 87-kDa product was detected with carboxyl terminally directed antiserum, indicating carboxyl terminal truncation. Pulse-chase experiments, using [35S]methionine/cysteine, showed that after 20 min pulse the main product in the cells was the 87-kDa protein. Cells chased for varying amounts of time exhibited a progressive increase in the intensity of a 66-kDa band, along with a corresponding decrease of the 87-kDa band. The 87-66 kDa conversion was nearly complete after 4 h of chase. This posttranslational processing was inhibited by the ionophore monensin, a Golgi disruptor, with a corresponding accumulation of the 87-kDa protein within the cell. Both the 87 kDa- and 66 kDa-labeled proteins were detected as membrane-bound rather than soluble proteins. The 87-kDa protein was the main product secreted by nonstimulated AtT-20 cells, while the 66-kDa product was only released when the cells were stimulated with CRF or BaCl2 and Bromo-cAMP.(ABSTRACT TRUNCATED AT 250 WORDS)     

4-O[(S)-1-carboxyethyl]-D-glucuronic acid: a component of the Klebsiella type 37 capsular polysaccharide

The acidic sugar component in the Klebsiella type 37 capsular polysaccharide (K 37) has been identified as 4-O-[(S)-1-carboxyethyl]-D-glucuronic acid. The identification is based upon chemical and spectroscopic studies, and the identity of the carboxyl-reduced sugar, 4-O-[(S)-2-(1-hydroxy)propyl]-D-glucose and derivatives, with the corresponding substances synthesized by an unambiguous route.     

Interaction between bacteriophage Sf6 and Shigella flexner.

The Shigella flexneri phage Sf6 has an isometric head with hexagonal symmetry 53nm in diameter. The noncontractile tails in 16 nm long and terminates with a base plate containing six spikes. Sf6 is typical of the C phages in the morphological classification of Bradley. Phage Sf6 processes alpha-1,3-endorhamnosidase activity as demonstrated by methylation and reducing end group sugar analyses of the products obtained on interaction with the O-polysaccharide chain of S.flexneri strains which have the O-group 3,4 antigen. The major end product was an octasaccharide with the following structure: Rha III-GlcNAc-Rha I-Rha II-Rha III-GlcNAc-Rha I-Rha II. Acetylation of 0-2 of rhamnose III of the O-polysaccharide chain, either brought about by Sf6 lysogenization or found in wild-type S. flexneri (3b) strains, prevented enzymatic hydrolysis. O-deacetylation of the polysaccharide chain again made it susceptible to the S6f endorhamnosidase.