Eubacterium alactolyticum Phylogenetically Groups with Eubacterium limosum, Acetobacterium woodii and Clostridium barkeri

Lactobacillus gastricus sp. nov., Lactobacillus antri sp. nov., Lactobacillus kalixensis sp. nov. and Lactobacillus ultunensis sp. nov., isolated from human stomach mucosa

In an attempt to study the composition of the Lactobacillus flora from mucosa of human stomach, 16S rRNA gene sequences of 129 isolates were analysed. For 15 of these, the results differed significantly from known sequences, and additional tests were performed to determine whether these isolates represented as yet unrecognized species. Phenotypic and genetic characteristics revealed that these isolates represented four novel Lactobacillus species. Two belong to the Lactobacillus reuteri and the other two to the Lactobacillus delbrueckii subgroup of Lactobacillus. The names Lactobacillus gastricus sp. nov., Lactobacillus antri sp. nov., Lactobacillus kalixensis sp. nov. and Lactobacillus ultunensis sp. nov. are proposed, with the respective type strains Kx156A7T (=LMG 22113T=DSM 16045T=CCUG 48454T), Kx146A4T (=LMG 22111T=DSM 16041T=CCUG 48456T), Kx127A2T (=LMG 22115T=DSM 16043T=CCUG 48459T) and Kx146C1T (=LMG 22117T=DSM 16047T=CCUG 48460T).

Lactobacillus saerimneri sp. nov., isolated from pig faeces

In studying the composition of the Lactobacillus flora of faeces from pigs fed different diets, isolates with notable differences in their 16S rRNA gene sequence compared to recognized species were found. Phenotypic characteristics together with 16S rRNA gene sequences revealed that the isolates represented a novel species belonging to the Lactobacillus mali subgroup of lactobacilli. The name Lactobacillus saerimneri sp. nov. is proposed (type strain GDA154T=LMG 22087T=DSM 16049T=CCUG 48462T).

Lactobacillus coryniformis subsp. coryniformis strain Si3 produces a broad-spectrum proteinaceous antifungal compound

The antifungal activity spectrum of Lactobacillus coryniformis subsp. coryniformis strain Si3 was investigated. The strain had strong inhibitory activity in dual-culture agar plate assays against the molds Aspergillus fumigatus, A. nidulans, Penicillium roqueforti, Mucor hiemalis, Talaromyces flavus, Fusarium poae, F. graminearum, F. culmorum, and F. sporotrichoides. A weaker activity was observed against the yeasts Debaryomyces hansenii, Kluyveromyces marxianus, and Saccharomyces cerevisiae. The yeasts Rhodotorula glutinis, Sporobolomyces roseus, and Pichia anomala were not inhibited. In liquid culture the antifungal activity paralleled growth, with maximum mold inhibition early in the stationary growth phase, but with a rapid decline in antifungal activity after 48 h. The addition of ethanol to the growth medium prevented the decline and gave an increased antifungal activity. The activity was stable during heat treatment and was retained even after autoclaving at 121 degrees C for 15 min. Maximum activity was observed at pH values of between 3. 0 and 4.5, but it decreased rapidly when pH was adjusted to a level between 4.5 and 6.0 and was lost at higher pH values. The antifungal activity was fully regained after readjustment of the pH to the initial value (pH 3.6). The activity was irreversibly lost after treatment with proteolytic enzymes (proteinase K, trypsin, and pepsin). The antifungal activity was partially purified using ion-exchange chromatography and (NH(4))(2)SO(4) precipitation, followed by gel filtration chromatography. The active compound(s) was estimated to have a molecular mass of approximately 3 kDa. This is the first report of the production of a proteinaceous antifungal compound(s) from L. coryniformis subsp. coryniformis.

Cloning, sequencing and expression of the gene encoding the coenzyme B12-dependent 2-methyleneglutarate mutase from Clostridium barkeri in Escherichia coli

The coenzyme B12 (adenosylcobalamin)-dependent 2-methyleneglutarate mutase catalyses the carbon skeleton rearrangement of 2-methyleneglutarate to (R)-3-methylitaconate in the fermentation of nicotinic acid by the strict anaerobic bacterium Clostridium barkeri. (a) The mgm gene encoding 2-methyleneglutarate mutase was cloned and its nucleotide sequence was determined. The deduced amino acid sequence revealed a 66.8-kDa protein of 614 amino acids. It shows significant similarity in its C-terminal part to that of other cobamide-dependent enzymes. Probably, this is the coenzyme-binding region. (b) The mgm gene from C. barkeri was expressed in Escherichia coli as was shown by SDS/PAGE and Western-blot analysis with rabbit antiserum directed against the native mutase. (c) Cell-free extracts from E. coli carrying the mgm gene showed 2-methyleneglutarate mutase activity that was strictly dependent on the addition of coenzyme B12. Experiments are presented which suggest that the expression product is an apoenzyme.