Archive for the ‘Biology’ Category

The interaction of path integration and terrestrial visual cues in navigating desert ants: what can we learn from path characteristics? [RESEARCH ARTICLE]

Cornelia Buehlmann, A. Sofia D. Fernandes, and Paul GrahamAnt foragers make use of multiple navigational cues to navigate through the world and the combination of innate navigational strategies and the learning of environmental information is the secr…

Thermal tachypnea in avian embryos [RESEARCH ARTICLE]

Kenia C. Bicego and Jacopo P. MortolaMany adult mammals and birds respond to heat with thermal tachypnea, an increase in breathing frequency with shallow tidal volume, with minimal increase in oxygen consumption (VO2). This pattern favors heat dissipat…

Transitional basal cells at the squamous–columnar junction generate Barrett’s oesophagus

In several organ systems, the transitional zone between different types of epithelium is a hotspot for pre-neoplastic metaplasia and malignancy, but the cells of origin for these metaplastic epithelia and subsequent malignancies remain unknown. In the case of Barrett’s oesophagus, intestinal metaplasia occurs at the gastro-oesophageal junction, where stratified squamous epithelium transitions into simple columnar cells. On the basis of a number of experimental models, several alternative cell types have been proposed as the source of this metaplasia but in all cases the evidence is inconclusive: no model completely mimics Barrett’s oesophagus in terms of the presence of intestinal goblet cells. Here we describe a transitional columnar epithelium with distinct basal progenitor cells (p63+KRT5+KRT7+) at the squamous–columnar junction of the upper gastrointestinal tract in a mouse model. We use multiple models and lineage tracing strategies to show that this squamous–columnar junction basal cell population serves as a source of progenitors for the transitional epithelium. On ectopic expression of CDX2, these transitional basal progenitors differentiate into intestinal-like epithelium (including goblet cells) and thereby reproduce Barrett’s metaplasia. A similar transitional columnar epithelium is present at the transitional zones of other mouse tissues (including the anorectal junction) as well as in the gastro-oesophageal junction in the human gut. Acid reflux-induced oesophagitis and the multilayered epithelium (believed to be a precursor of Barrett’s oesophagus) are both characterized by the expansion of the transitional basal progenitor cells. Our findings reveal a previously unidentified transitional zone in the epithelium of the upper gastrointestinal tract and provide evidence that the p63+KRT5+KRT7+ basal cells in this zone are the cells of origin for multi-layered epithelium and Barrett’s oesophagus.

Pseudaspidimerus palatus, a new species of the genus Pseudaspidimerus Kapur, 1948 from the Malay Peninsula (Coleoptera, Coccinellidae)

ZooKeys 706: 109-115
DOI: 10.3897/zookeys.706.18081
Authors: Lizhi Huo, Wenjing Li, Xingmin Wang
Abstract: A new species of the genus Pseudaspidimerus Kapur, 1948 (Coleoptera: Coccinellidae), Pseudaspidimerus palatus Huo & Wang…

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