T could only utilize one of the 50 substrates tested, ribose, although it does slowly utilize galactose. In the API ZYM system, strain WDC04 T was positive for leucine arylamidase, valine arylamidase, cysteine arylamidase (weakly), naphthol-AS-BIphosphohydrolase and b-galactosidase activities. Total genomic DNA was sequenced from strain WDC04 T using a whole-genome shotgun strategy on a 454 GS Titanium pyrosequencer.

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 gpDlike 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.

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, an obligate heterofermentative nonstarter lactic acid bacteria (NSLAB) implicated in causing gas defects in aged cheeses, was originally isolated from an aged Cheddar produced in Logan, Utah. To determine the geographical distribution of this organism, we isolated slow-growing NSLAB from cheeses collected in different regions of the United States, Australia, New Zealand, and Ireland. Seven of the cheeses showed significant gas defects and 12 did not. Nonstarter lactic acid bacteria were isolated from these cheeses on de Man, Rogosa, and Sharpe medium supplemented with ribose, a preferred substrate for Lb. wasatchensis. Identification was confirmed with 16S rRNA gene sequencing and the API50CH (bioMérieux, Marcy l'Etoile, France) carbohydrate panel. Isolates were also compared with one another by using repetitive element sequence-based PCR (rep-PCR). Lactobacillus wasatchensis was isolated only from cheeses demonstrating late-gas development and was found in samples from 6 of the 7 cheeses. This supports laboratory evidence that this organism is a causative agent of late gas production defects. The rep-PCR analysis produced distinct genetic fingerprints for isolates from each cheese, indicating that Lb. wasatchensis is found in several regions across the United States and is not a local phenomenon.

Paucilactobacillus wasatchensis, a nonstarter lactic acid bacteria, can cause late gas production and splits and cracks in aging cheese when it metabolizes 6-carbon substrates, particularly galactose, to a 5-carbon sugar, resulting in the release of CO 2 . Previous studies have not explained late gas production in aging cheese when no galactose is present. Based on the genome sequence of Pa. wasatchensis WDC04, genes for potential metabolic pathways were mapped using knowledgebase predictive biology software. This metabolic modeling predicted Pa. wasatchensis WDC04 could metabolize gluconate. Gluconate contains 6 carbons, and Pa. wasatchensis WDC04 contains genes to convert it to 6-P-gluconate and then to ribulose-5-P by using 6-phosphogluconate dehydrogenase in a decarboxylating step, producing CO 2 during its metabolism. The goal of this study was to determine if sodium gluconate, often added to cheese to reduce calcium lactate crystal formation, could be metabolized by Pa. wasatchensis WDC04, resulting in gas production. Carbohydrate-restricted DeMan, Rogosa, and Sharpe broth was mixed with varying ratios of ribose, sodium gluconate, or d-galactose (total added substrate content of 1% wt/vol). Oxyrase (Oxyrase Inc.; 1.8% vol/vol) was also used to mimic the anaerobic environment of cheese aging in selected tubes. Tubes were inoculated with a 4-d culture of Pa. wasatchensis WDCO4, and results were recorded over 8 d. When inoculated into carbohydrate-restricted De-Man, Rogosa, and Sharpe broth containing only sodium gluconate as the added substrate, Pa. wasatchensis WDC04 grew, confirming gluconate utilization. Of the 10 ratios used, Pa. wasatchensis WDC04 produced gas in 6 scenarios, with the most gas production resulting from the ratio of 100% sodium gluconate with no added ribose or galactose. It was confirmed that obligately heterofermentative nonstarter lactobacilli such as Pa. wasatchensis WDC04 can utilize sodium gluconate to produce CO 2 gas. Addition of sodium gluconate to cheese thus becomes another risk factor for unwanted gas production and formation of slits and cracks.