Invited review: Review of taxonomic changes in dairy-related lactobacilli.

The genus Lactobacillus has represented an extremely large and diverse collection of bacteria that populate a wide range of habitats, and which may have industrial applications. Researchers have grappled with the immense genetic, metabolic, and ecological diversity within the genus Lactobacillus for many years. As a result, the taxonomy of lactobacilli has been extensively revised, incorporating new genus names for many lactobacilli based on their characteristics including genomic similarities. As a result, many lactobacilli traditionally associated with dairy products now have new genus names and are grouped into new clades or clusters of species. In this review, we examine how the taxonomic restructuring of the genus Lactobacillus will affect the dairy industry and discuss lactobacilli associated with dairy production, processing, and those that confer possible health benefits when delivered by dairy products.

Lactobacillus wasatchensis sp. nov., a non-starter lactic acid bacteria isolated from aged Cheddar cheese.

A Gram-stain positive, rod-shaped, non-spore-forming strain (WDC04T), which may be associated with late gas production in cheese, was isolated from aged Cheddar cheese following incubation on MRS agar (pH 5.2) at 6 °C for 35 days. Strain WDC04T had 97 % 16S rRNA gene sequence similarity with Lactobacillus hokkaidonensis DSM 26202T, Lactobacillus oligofermentans 533, 'Lactobacillus danicus' 9M3, Lactobacillus suebicus CCUG 32233T and Lactobacillus vaccinostercus DSM 20634T. API 50 CH carbohydrate fermentation panels indicated strain WDC04T could only utilize one of the 50 substrates tested, ribose, although it does slowly utilize galactose. In the API ZYM system, strain WDC04T was positive for leucine arylamidase, valine arylamidase, cysteine arylamidase (weakly), naphthol-AS-BI-phosphohydrolase and ß-galactosidase activities. Total genomic DNA was sequenced from strain WDC04T using a whole-genome shotgun strategy on a 454 GS Titanium pyrosequencer. The sequence was assembled into a 1.90 Mbp draft genome consisting of 105 contigs with preliminary genome annotation performed using the RAST algorithm (rast.nmpdr.org). Genome analysis confirmed the pentose phosphate pathway for ribose metabolism as well as galactose, N-acetylglucosamine, and glycerol fermentation pathways. Genomic analysis places strain WDC04T in the obligately heterofermentative group of lactobacilli and metabolic results confirm this conclusion. The result of genome sequencing, along with 16S rRNA gene sequence analysis, indicates WDC04T represents a novel species of the genus Lactobacillus, for which the name Lactobacillus wasatchensis sp. nov. is proposed. The type strain is WDC04T ( = DSM 29958T = LMG 28678T).

Sequence and structural characterization of great salt lake bacteriophage CW02, a member of the T7-like supergroup.

Halophage CW02 infects a Salinivibrio costicola-like bacterium, SA50, isolated from the Great Salt Lake. Following isolation, cultivation, and purification, CW02 was characterized by DNA sequencing, mass spectrometry, and electron microscopy. A conserved module of structural genes places CW02 in the T7 supergroup, members of which are found in diverse aquatic environments, including marine and freshwater ecosystems. CW02 has morphological similarities to viruses of the Podoviridae family. The structure of CW02, solved by cryogenic electron microscopy and three-dimensional reconstruction, enabled the fitting of a portion of the bacteriophage HK97 capsid protein into CW02 capsid density, thereby providing additional evidence that capsid proteins of tailed double-stranded DNA phages have a conserved fold. The CW02 capsid consists of bacteriophage lambda gpD-like densities that likely contribute to particle stability. Turret-like densities were found on icosahedral vertices and may represent a unique adaptation similar to what has been seen in other extremophilic viruses that infect archaea, such as Sulfolobus turreted icosahedral virus and halophage SH1.