Lycoposerramine A (1) is a pentacyclic alkaloid isolated in 2001 by Takayama and co-workers. A concise synthesis of a model compound 8 for the tetracyclic core of this natural product is described. Key steps include the desymmetrising free-radical cyclisation of compound 7 to give compound 18 and spirocyclisation of compound 26 to give compound 8. Earlier approaches using a novel high-yielding ...

A concise route to functionalized 14-membered macrolides related to erythronolide A was achieved. Key steps include the simultaneous formation of bis[allenic] substrates, efficient macrolactonization, highly stereoselective oxidation to the corresponding bis[spirodiepoxide], and nucleophilic spirodiepoxide opening. The structure and reactivity of these macrolides, and the strategy that led to t...

This cross-sectional epidemiologic study was conducted in 150 randomly selected farrow-to-finish pig herds to investigate descriptive epidemiological characteristics of infections with three different serovars of Actinobacillus pleuropneumoniae, and to identify risk factors for the within-herd seroprevalences of these serovars. Different farm characteristics (n = 28) were examined as potential ...

Restriction enzyme analysis of PCR-amplified 16S rRNA genes was used to distinguish among clinical isolates of Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, and Haemophilus paraphrophilus which were originally identified by conventional phenotypic methods. This PCR-based method is a reliable and rapid alternative to conventional methods for identification of these bacterial spe...

Clinical Actinobacillus actinomycetemcomitans produces cytolethal distending toxin (CDT) with titers ranging from 10(2) to 10(8) U/mg. Single nucleotide polymorphism analysis of the cdt gene in clinical isolates identified a variation of a single amino acid at residue 281 of CdtB, which significantly affected CDT toxicity by modulating the chromatin-degrading activity of CdtB.

The stability of hemolytic activity, antibiotic resistance and plasmid detection in Actinobacillus actinomycetemcomitans isolates were studied. These characteristics were stable for all experimental conditions. All tested isolates lost or changed some phenotypic characteristics such as colonial morphology and growth in liquid medium.

The species of Capnocytophaga and Aggregatibacter are normal flora and mostly cause periodontal diseases. The soft tissue infection caused by Aggregatibacter often is associated with Actinomyces species. Beside, most Capnocytophaga infections are described in immunocompromised patients. We identified facial cellulitis caused by Capnocytophaga spp and Aggregatibacter (Actinobacillus) actinomycet...

Abundant Secretion of Bioactive Interleukin-1 by Human Macrophages Induced by Actinobacillus actinomycetemcomitans Leukotoxin P. Kelk, R. Claesson, L. Hänström, U. H. Lerner, S. Kalfas, and A. Johansson* Divisions of Periodontology, Oral Microbiology, and Oral Cell Biology, Department of Odontology, Faculty of Medicine, Umeå University, Umeå, Sweden, and School of Dentistry, Aristotle Universit...

Oligonucleotide primers specific for gene clusters involved in the biosynthesis of serotype-specific polysaccharide antigens were designed to identify Actinobacillus actinomycetemcomitans serotypes a to e using the multiplex PCR. This method may be useful for serotype-specific genotyping rapidly and directly from clinical samples containing various organisms.

A. Mukhopadhyay, M. R. Murty and K. Srinivas have recently studied various arithmetic properties of the discriminant ∆n(a, b) of the trinomial fn,a,b(t) = t n + at+ b, where n ≥ 5 is a fixed integer. In particular, it is shown that, under the abc-conjecture, for every n ≡ 1 (mod 4), the quadratic fields Q (√ ∆n(a, b) ) are pairwise distinct for a positive proportion of such discriminants with i...