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Campylobacter jejuni remains the leading cause of bacterial gastroenteritis in developed countries, and yet little is known concerning the mechanisms by which this fastidious organism survives within its environment. We have demonstrated that C. jejuni 11168 can form biofilms on a variety of surfaces. Proteomic analyses of planktonic and biofilm-grown cells demonstrated differences in protein expression profiles between the two growth modes. Proteins involved in the motility complex, including the flagellins (FlaA, FlaB), the filament cap (FliD), the basal body (FlgG, FlgG2), and the chemotactic protein (CheA), all exhibited higher levels of expression in biofilms than found in stationary-phase planktonic cells. Additional proteins with enhanced expression included those involved in the general (GroEL, GroES) and oxidative (Tpx, Ahp) stress responses, two known adhesins (Peb1, FlaC), and proteins involved in biosynthesis, energy generation, and catabolic functions. An aflagellate flhA mutant not only lost the ability to attach to a solid matrix and form a biofilm but could no longer form a pellicle at the air-liquid interface of a liquid culture. Insertional inactivation of genes that affect the flagellar filament (fliA,flaA,flaB, flaG) or the expression of the cell adhesin (flaC) also resulted in a delay in pellicle formation. These findings demonstrate that the flagellar motility complex plays a crucial role in the initial attachment of C. jejuni 11168 to solid surfaces during biofihn formation as well as in the cell-to-cell interactions required for pellicle formation. Continued expression of the motility complex in mature biofilms is unusual and suggests a role for the flagellar apparatus in the biofilm phenotype.

In eukaryotes, N-linked protein glycosylation is a universal modification involving addition of preformed oligosaccharides to select Asn-Xaa-Ser/Thr motifs and influencing multiple biological events. We recently demonstrated that Campylobacter jejuni is the first member of the Bacteria to possess an N-linked glycan pathway. In this study, high-resolution magic angle spinning nuclear magnetic resonance (HR-MAS NMR) was applied to probe and quantitate C. jejuni N-glycan biosynthesis in vivo. To confirm HR-MAS NMR findings, glycosylation mutants were screened for chicken colonization potential, and glycoproteins were examined by mass spectrometry and lectin blotting. Consistent with the mechanism in eukaryotes, the combined data indicate that bacterial glycans are assembled en bloc, emphasizing the evolutionary conservation of protein N glycosylation. We also show that under the conditions examined, PgIG plays no role in glycan biosynthesis, PgII is the glucosyltransferase and the putative ABC transporter, and WlaB (renamed PglK) is required for glycan assembly. These studies underpin the mechanism of N-linked protein glycosylation in Bacteria and provide a simple model system for investigating protein glycosylation and for exploitation in glycoengineering.

Research has been conducted on flavoprotein cyclopentanone 1,2-monooxygenase, produced by Pseudomonas sp. strain NCIMB 9872. The results of the functional analysis of the enzymes involved in cyclopentanol degradation pathway in Pseudomonas sp. strain NCIMB 9872 and of the gene cloning and nucleotide sequencing are presented.

Research has been conducted on Streptococus mutants and its ability to form biofilms and survive acidic pH. Results suggest that gene product in S. mutans can act as a pH sensor and that the two-component signal transduction system is a regulatory system involved in acid resistance and biofilm formation in S. mutans.

Research has been conducted on Streptococcus mutans quorum-sensing signaling system essential for genetic competence. The role of the system in S. mutans ability to initiate biofilm formation has been investigated and the results are discussed.

Abstract: Chemoenzymatic deracemization was applied to prepare d‐valine from racemic valine ethyl ester or l‐valine ethyl ester in high yield (up to 95 %) with excellent optical purity (>99 % ee) by employing a newly evolved cyclohexylamine oxidase (CHAO) variant Y321I/M226T exhibiting catalytic efficiency that was 30 times higher than that of the wildtype CHAO. Interestingly, CHAO and its variants showed opposite enantioselectivity for valine ethyl ester and phenylalanine ethyl ester. [ABSTRACT FROM AUTHOR]