The evolutionary importance of cell ratio between notochordal and nucleus pulposus cells: an experimental 3-D co-culture study

Notochordal cells and nucleus pulposus cells are co-existing in the intervertebral disc at various ratios among different mammalians. This fact rises the question about the interactions and the evolutionary relevance of this phenomenon. It has been described that these relatively large notochordal cells are mainly dominant in early lifetime of all vertebrates and then differences occur with ageing. Human, cattle, sheep, and goat lose the cells with age, whereas rodents and lagomorphs maintain these throughout their lifetime.

Sequence analysis of a 212 kb defensin gene cluster on ECA 27q17

Defensins are a family of evolutionary ancient antimicrobial peptides consisting of three sub-families: alpha-, beta- and theta-defensins. This investigation was focused on the genomic characterization of equine beta-defensins and the investigation of the potential clustering of beta-defensin genes in the equine genome. Six genomic BAC clones were isolated from the CHORI-241 library and one of these was mapped by FISH to ECA 27q17. This location was confirmed by RH-mapping. The contiguous 212 kb sequence of this clone was determined. Sequence analysis revealed the identification of ten pseudogenes and nine genes, six of which were highly homologous to human beta-defensin DEFB4. Clustering of the beta-defensin genes was confirmed and the order of the genes on the analyzed BAC was related to the corresponding defensin cluster on HSA 8. The knowledge about the sequence and the genomic structure of the equine beta-defensin genes will improve the classification of different paralogous defensin genes and is a prerequisite for subsequent functional studies. Additionally, the first alpha-defensin-like sequence outside the groups of primates, lagomorphs and rodents (glires) was identified.

Rapid diagnosis and quantification of Francisella tularensis in organs of naturally infected common squirrel monkeys (Saimiri sciureus)

Francisella tularensis, a small Gram-negative facultative intracellular bacterium, is the causative agent of tularaemia, a severe zoonotic disease transmitted to humans mostly by vectors such as ticks, flies and mosquitoes. The disease is endemic in many parts of the northern hemisphere. Among animals, the most affected species belong to rodents and lagomorphs, in particular hares. However, in the recent years, many cases of tularaemia among small monkeys in zoos were reported. We have developed a real-time PCR that allows to quantify F. tularensis in tissue samples. Using this method, we identified the spleen and the kidney as the most heavily infected organ containing up to 400 F. tularensis bacteria per simian host cell in two common squirrel monkeys (Saimiri sciureus) from a zoo that died of tularaemia. In other organs such as the brain, F. tularensis was detected at much lower titres. The strain that caused the infection was identified as F. tularensis subsp. holarctica biovar I, which is susceptible to erythromycin. The high number of F. tularensis present in soft organs such as spleen, liver and kidney represents a high risk for persons handling such carcasses and explains the transmission of the disease to a pathologist during post-mortem analysis. Herein, we show that real-time PCR allows a reliable and rapid diagnosis of F. tularensis directly from tissue samples of infected animals, which is crucial in order to attempt accurate prophylactic measures, especially in cases where humans or other animals have been exposed to this highly contagious pathogen.