Polyploidy in Cupressaceae: Discovery of a new naturally occurring tetraploid,Xanthocyparis vietnamensis

While polyploidy (whole-genome multiplication) is generally considered rare in extant gymnosperms (with the exception of Ephedra, Ephedraceae), the occurrence of sporadic polyploid individuals belonging to various genera in the conifer family Cupressaceae has been reported in the literature. In addition, recent studies have revealed that polyploidy is not uncommon in the genus Juniperus (Cupressaceae), with tetraploid and hexaploid individuals reported in individuals collected from wild populations. Given these findings, we undertook a comprehensive screening of ploidy levels in 32 species belonging to the four genera that are phylogenetically closest to Juniperus (i.e.,Callitropsis, Hesperocyparis, Xanthocyparis, and Cupressus), referred to as the CaHXCu complex. In addition, we also determined the ploidy level of two accessions in the poorly studied tetraploid, Fitzroya cupressoides. Using flow cytometry together with published chromosome counts to assign ploidy levels, we show that all species of the CaHXCu complex are diploid except Xanthocyparis vietnamensis, which is tetraploid, with a genome size of 44.60 pg/2 C. This study opens up new opportunities for studying the impact and consequences of polyploidy on the evolution and adaptation of species in Cupressaceae.     

Model components of luminol chemiluminescence generated by PMNL

The production of activated oxygen species (AOS) by neutrophils (PMNL) is thought to play a key role in the host defence against invading microorganisms. However, the oxygen metabolites are toxic not only to the invading bacteria but also to the surrounding tissue. The oxidative metabolites production can be evaluated by means of chemiluminescent methods. In this study, the possibility of a new analytical approach for quantitative assessment of chemiluminescent kinetics (AOS generation) of isolated PMNL was estimated.

Based on the assumption that the kinetics of luminol-amplified chemiluminescence (LCL) of stimulated PMNL possesses a time-probabilistic nature, this kinetics was described with three components. These components, obtained from different investigated systems, were analyzed and a conclusion was made that the first and the second component represent the processes resulting in extra-and intracellular myeloperoxidase (MPO)-dependent light emission (AOS generation), respectively. The second component was found to be completely dependent on the stimulus ingestion. The third component was not completely MPO-dependent and complicated for interpretation. This component was weakly dependent on the stimulus ingestion, and presents at least some intracellular processes different from those presented by the second component.

A conclusion is made that the examined approach for analysis of LCL kinetics allows an assessment of extra-and intracellularly generated quantities of AOS by stimulated PMNL. The assessment could be done for emitting systems in which no additional modificators are used.     

Detection of microbial-derived fatty acids in carious dentin by gas chromatography and gas chromatography-mass spectrometry

The aim of the present study was to analyze the fatty acid content of carious and sound human dentin. Gas chromatography and gas chromatography-mass spectrometry revealed the presence of fatty acids of C₁₀-C₁₈ size in the carious dentin, whereas fatty acids of C₁₆ size were present in minute amounts in three samples of the corresponding sound dentine controls. No fatty acids were detected in the other sound dentin control samples. The source of fatty acids was considered to be microorganisms invading the dentin during the progression of the caries lesion. The presence of bacterial fatty acids in carious dentin may serve as a marker for the pathological process and thus contribute to the understanding of the mechanisms involved.