The precursor polypeptides of periplasmic proteins binding seven types of redox cofactor have unusually long signal sequences bearing a consensus (S/T)-R-R-x-F-L-K motif immediately before the hydrophobic region. Such "double-arginine' signal sequences are not, in general, found on the precursors of other periplasmic proteins. It is suggested that precursor proteins with double-arginine signal sequences share a common specialization in their export pathway. The nature of this specialization, the structure of the double-arginine signal sequences, and the possible relationship with the double-arginine signal peptide-dependent thylakoid import pathway are discussed.

A common export pathway for proteins binding complex redox cofactors

An operon encoding four proteins required for bacterial cellulose biosynthesis (bcs) in Acetobacter xylinum was isolated via genetic complementation with strains lacking cellulose synthase activity. Nucleotide sequence analysis indicated that the cellulose synthase operon is 9217 base pairs long and consists of four genes. The four genes--bcsA, bcsB, bcsC, and bcsD--appear to be translationally coupled and transcribed as a polycistronic mRNA with an initiation site 97 bases upstream of the coding region of the first gene (bcsA) in the operon. Results from genetic complementation tests and gene disruption analyses demonstrate that all four genes in the operon are required for maximal bacterial cellulose synthesis in A. xylinum. The calculated molecular masses of the proteins encoded by bcsA, bcsB, bcsC, and bcsD are 84.4, 85.3, 141.0, and 17.3 kDa, respectively. The second gene in the operon (bcsB) encodes the catalytic subunit of cellulose synthase. The functions of the bcsA, bcsC, and bcsD gene products are unknown. Bacterial strains mutated in the bcsA locus were found to be deficient in cellulose synthesis due to the lack of cellulose synthase and diguanylate cyclase activities. Mutants in the bcsC and bcsD genes were impaired in cellulose production in vivo, even though they had the capacity to make all the necessary metabolic precursors and cyclic diguanylic acid, the activator of cellulose synthase, and exhibit cellulose synthase activity in vitro. When the entire operon was present on a multicopy plasmid in the bacterial cell, both cellulose synthase activity and cellulose biosynthesis increased. When the promoter of the cellulose synthase operon was replaced on the chromosome by E. coli tac or lac promoters, cellulose production was reduced in parallel with decreased cellulose synthase activity. These observations suggest that the expression of the bcs operon is rate-limiting for cellulose synthesis in A. xylinum.

https://www.pnas.org/content/pnas/87/20/8130.full.pdf

Genetic organization of the cellulose synthase operon in Acetobacter xylinum.

Publisher Summary The chapter discusses the respiratory chains and bioenergetics of acetic acid bacteria. Acetic acid bacteria are obligate aerobes and well known as “vinegar producers.” They produce acetic acid from ethanol by two sequential catalytic reactions of membrane-bound alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). Besides alcohols and aldehydes, acetic acid bacteria are able to oxidize various sugars and sugar alcohols such as D-glucose, glycerol, and D-sorbitol. Such oxidation reactions are called “oxidative fermentations”, because they involve incomplete oxidation of alcohols or sugars accompanied by accumulation of the corresponding oxidation products in huge amounts in the growth medium. Bacteria capable of effecting oxidative fermentations are called “oxidative bacteria,” of which the most prominent are acetic acid bacteria. Acetic acid bacteria are also important for the fermentation industries to produce biomaterials such as vinegar and L-sorbose. Acetic acid bacteria are classified into two genera, Gluconobacter and Acetobacter of the family Acetobacteraceae. Gluconobacter species catalyze highly active oxidation reactions on ethanol or D-glucose— including also oxidative reactions on sugars such as D-gluconic acid, D-sorbitol, and glycerol. By contrast, Acetobacter species have a highly active ethanoloxidizing system but not enzymes for sugar oxidation. The respiratory chain in Acetobacter spp. has ubiquinone, cytochrome b , cytochrome c , and a terminal ubiquinol oxidase, which is either cytochrome a 1 or cytochrome o .

Respiratory chains and bioenergetics of acetic acid bacteria.

An ink-jet recording material comprising an ink receiving layer (A) present near a supporting material which comprises precipitation method silica particles having an average secondary particle diameter of 500 nm or less, or precipitation method silica particles having an average secondary particle diameter of 500 nm or less and gas phase method silica particles having an average secondary particle diameter of 500 nm or less, and further comprises poly(vinyl alcohol) in an amount of less than 20 parts by weight relative to 100 parts by weight of the total silica particles in the ink receiving layer (A), and an ink receiving layer (B) being apart form the supporting material which comprises at least one type of particles selected from among those of a gas phase method silica, alumina and an alumina hydrate and poly(vinyl alcohol) in an amount of less than 25 parts by weight relative to 100 parts by weight of the at least one type of particles.

Ink-jet recording material

Cellulose is the most abundant biological polymer on Earth. It is found in wood and cotton, and forms the basic structural foundation of the cell wall of almost all eukaryotic plants. Bacteria are ...

Biogenesis of bacterial cellulose.

The nucleotide sequence of the membrane-bound aldehyde dehydrogenase (ALDH) gene from an industrial vinegar producer, Acetobacter polyoxogenes, was determined. Comparison of the sequence with the NH2-terminal amino acid sequence of the mature ALDH and determination of the actual translational initiation codon by means of in vitro manipulation of the upstream and proximal regions of the cloned gene showed that ALDH was primarily translated as a 773-amino-acid protein and that the 44-amino-acid sequence at the NH2-terminus, which probably serves as a signal peptide, was processed during maturation and localization in the membrane. When ALDH was expressed in a large quantity in Escherichia coli cells after the coding region had been placed downstream of the lac promoter, the ALDH protein, which still contained the signal peptide and had no ALDH activity, was localized in the membrane fraction.

Nucleotide sequence of the membrane-bound aldehyde dehydrogenase gene from Acetobacter polyoxogenes.

Orotate as a β-alanine donor for anserine and carnosine biosynthesis,and effects of actinomycin D and azauracil on their pathway

An improved method for transformation of derivative strains of A. aceti subsp. aceti No. 1023 with plasmid DNA has been developed. Addition of polyethylene glycol or dimethylsulfoxide increased the transformation efficiency by a factor of about ten. In the presence of PEG 4,000, various transformation conditions were examined. Cells were also made transformation competent by treatment with other divalent cations than Ca2+ . The pH of the buffer did not affect the efficiency significantly. The growth phase influenced the efficiency. Mutants showing high competence were derived by treatment with N-methyl-N′-nitro-N-nitrosoguanidine. By the improved method using the highly transformable mutants, a transformation efficiency of approximately 105 transformants per γg plasmid DNA was achieved.

Improved Transformation Method for Acetobacter with Plasmid DNA

A finished vinegar having an acetic acid concentration higher than 20 percent weight by volume is produced by repeating a fermentation cycle wherein a broth is fermented at 27°-32° C. in a 1st submerged fermentation tank by a continuous batch process, and, when the acetic acid concentration of the fermenting broth reaches 12-15 percent weight by volume, the large part of the fermenting broth in the 1st fermentation tank is withdrawn and charged in a 2nd submerged fermentation tank. The 1st fermentation tank is recharged with a mash and the fermentation of the fermenting broth in the 2nd tank is continued under aeration while lowering the temperature of the fermenting broth in such manner that the final fermentation temperature does not fall below 18° C. and the lowering temperature does not become higher than the temperature once lowered.

Process for the production of vinegar with high acetic acid concentration

PURPOSE: To obtain a food raw material having smooth palatability and excellent emulsifiability and free from rough taste such as bitter taste and astringent taste and disagreeable smell such as soybean smell by treating soya milk or soya milk raw material with a lab-enzyme produced by a lab-enzyme-producing micro-organism belonging to genus Aspergillus, etc. CONSTITUTION: The objective food raw material suitable as a substitute for food emulsifier, oil and fat, etc., is produced by treating soya milk or a soya milk raw material with a lab-enzyme having low protease activity and high lab-enzyme activity against protease activity and produced by the culture of microorganism belonging to genus Aspergillus, genus Mucor or genus Rhizopus and capable of producing the lab-enzyme. COPYRIGHT: (C)1990,JPO&Japio

Hajime Okumura

Papers

Nucleotide sequence of the membrane-bound aldehyde dehydrogenase gene from Acetobacter polyoxogenes.

Orotate as a β-alanine donor for anserine and carnosine biosynthesis,and effects of actinomycin D and azauracil on their pathway

Improved Transformation Method for Acetobacter with Plasmid DNA

Process for the production of vinegar with high acetic acid concentration

Food raw material and production thereof