Following the advent of molecular assays that measure T cell receptor excision circles (TRECs) present in recent thymic emigrants, it has been conclusively shown that thymopoiesis persists in most adults, but that functional output decreases with age, influencing the maintenance of a diverse and functional T cell receptor (TCR) repertoire. Space flight has been shown to result in a variety of p...

This paper investigates the interaction between cultural evolution and biological evolution in the emergence of phonemic coding in speech. It is observed that our nearest relatives, the primates, use holistic utterances, whereas humans use phonemic utterances. It can therefore be argued that our last common ancestor used holistic utterances and that these must have evolved into phonemic utteran...

We investigate the problem of inferring contiguous ancestral regions (CARs) of the genome of the last common ancestor of all extant amniotes, based on the currently sequenced and assembled amniote genomes as ingroups and three teleost fish genomes as outgroups. We combine a methodological framework using conserved syntenies computed from whole genome alignments of amniote species together with ...

In contrast to adults, the murine neonatal CD4+ compartment contains a high frequency of recent thymic emigrants (RTEs). However, the functional capabilities of these cells in neonates are relatively unknown. Moreover, it has not been determined whether RTEs from neonates and adults are comparable. Here we have directly compared neonatal and adult CD4+ RTEs for the first time, using a transgeni...

The detection of superinfection involves an assessment whether the sequences obtained from a patient diverged from a last common ancestor within that patient, or several lineages were introduced by independent infection events. First we tested whether sequence divergence can be used to identify viral sequences of polyphyletic origin. In principle, a conservative divergence threshold could be es...

UNLABELLED PREMISE OF THE STUDY Utah agave (Agave utahensis) and its putative subspecies, A. utahensis subsp. kaibabensis and A. utahensis subsp. utahensis, are keystone species of the Mojave Desert and Colorado Plateau in the southwestern United States. Here we developed microsatellite markers to study population structure and genetic diversity of the two subspecies of A. utahensis. • MET...

Three known flavones and seven known homoisoflavonoids were isolated from the methanolic extract of the leaves of Agave sisalanaPerrine ex Engelm. Their structures were elucidated on the basis of spectroscopic analysis. The isolated compounds were also evaluated for immunopharmacological activity. PBMC were used as target cells, and cell proliferation was determined by (3)H-thymidine uptake. (+...

Phytophthora infestans (Mont.) de Bary, the causal agent of potato late blight, was responsible for the Irish potato famine of the 1840s. Initial disease outbreaks occurred in the US in 1843, two years prior to European outbreaks. We examined the evolutionary relationships and source of the 19th-century outbreaks using herbarium specimens of P. infestans from historic (1846-1970) and more recen...

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