Viable microbes in ice: Application of molecular assays to McMurdo Dry Valley lake ice communities

The permanent ice covers of the McMurdo Dry Valley lakes, Antarctica, are colonized by a diverse microbial assemblage. We collected ice cores from Lakes Fryxell, Hoare and Bonney. Propidium monoazide (PMA) was used in combination with quantitative PCR (qPCR) and denaturing gradient gel electrophoresis (DGGE) to examine membrane integrity of...

Mathematical design of prokaryotic clone-based microarrays

Background: Clone-based microarrays, on which each spot represents a random genomic fragment, are a good alternative to open reading frame-based microarrays, especially for microorganisms for which the complete genome sequence is not available. Since the generation of a genomic DNA library is a random process, it is beforehand uncertain which...

Molecular cloning and characterization of the alkaline ceramidase from Pseudomonas aeruginosa PA01

Ceramidase (CDase) hydrolyzes the amide bond in ceramides to yield free fatty acid and sphingosine. From a 3-L Pseudomonas aeruginosa PA01 culture, 70 μg of extracellular alkaline, Ca2+-dependent CDase, was purified to homogeneity, the N-terminal sequence was determined, and the CDase gene was cloned. The CDase gene encodes a 670 amino acid...

Efficient screening methods for glucosyltransferase genes in Lactobacillus strains

Limited information is available about homopolysaccharide synthesis in the genus Lactobacillus. Using efficient screening techniques, extracellular glucosyltransferase (GTF) enzyme activity, resulting in α-glucan synthesis from sucrose, was detected in various lactobacilli. PCR with degenerate primers based on homologous boxes of known...

Expression of the Pycnoporus cinnabarinus laccase gene in Aspergillus niger and characterization of the recombinant enzyme

Pycnoporus cinnabarinus laccase lac1 gene was overexpressed in Aspergillus niger, a well-known fungal host producing a large amount of homologous or heterologous enzymes for industrial applications. The corresponding cDNA was placed under the control of the glyceraldehyde-3-phosphate dehydrogenase promoter as a strong and constitutive promoter....

Expression of the xylulose 5-phosphate phosphoketolase gene, xpkA, from Lactobacillus pentosus MD363 is induced by sugars that are fermented via the phosphoketolase pathway and is repressed by glucose mediated by CcpA and the mannose phosphoenolpyruvate phosphotransferase system

Purification of xylulose 5-phosphate phosphoketolase (XpkA), the central enzyme of the phosphoketolase pathway (PKP) in lactic acid bacteria, and cloning and sequence analysis of the encoding gene, xpkA, from Lactobacillus pentosus MD363 are described, xpkA encodes a 788-amino-acid protein with a calculated mass of 88,705 Da. Expression of xpkA...

Lactic acid bacteria: Genetics, metabolism and applications

Chemicals/CAS: Lactic Acid, 50-21-5

Complement-resistant Moraxella catarrhalis forms a genetically distinct lineage within the species

Moraxella catarrhalis is a bacterial species that has been implicated in 15^20% of all cases of otitis media in the USA and the complementresistantvariant of M. catarrhalis has been considered particularly pathogenic. A collection of geographically diverse, complement-sensitive (n = 28) and -resistant strains (n = 47) of M. catarrhalis was...

Isolation and characterization of promoter regions from Streptococcus gordonii CH1

We aimed to identify transcription signal sequences from Streptococcus gordonii strain CH1 by random chromosomal cloning. Five genomic fragments from a Sau3A digest, which constitutively activated transcription of a promoterless spectinomycin resistance gene in this strain, were isolated and characterized. Additionally, one promoter fragment was...

Cloning, sequence analysis, and characterization of the genes involved in isoprimeverose metabolism in Lactobacillus pentosus

Two genes, xylP and xylQ, from the xylose regulon of Lactobacillus pentosus were cloned and sequenced. Together with the repressor gene of the regulon, xylR, the xylPQ genes form an operon which is inducible by xylose and which is transcribed from a promoter located 145 bp upstream of xylP. A putative xylR binding site (xylO) and a cre-like...