Mate choice in a promiscuous poison frog.

In many animal species, members of one sex, most often females, exhibit a strong preference for mating partners with particular traits or resources. However, when females sequentially mate with multiple partners, strategies underlying female choice are not very well understood. Particularly, little is known if under such sequential polyandry females mate truly randomly, or if they actively try to spread mating events across multiple partners.

Identification and Characterization of and subsp. Zinc Transporters.

Zinc uptake in bacteria is essential to maintain cellular homeostasis and survival. ZnuABC is an important zinc importer of numerous bacterial genera, which is expressed to restore zinc homeostasis when the cytosolic concentration decreases beyond a critical threshold. Upon zinc limitation the fast-growing nonpathogenic organism (MSMEG) as well as the ruminant pathogen subsp.

Subunit Interactions and cooperativity in the microtubule-severing AAA ATPase spastin.

Spastin is a hexameric ring AAA ATPase that severs microtubules. To see whether the ring complex funnels the energy of multiple ATP hydrolysis events to the site of mechanical action, we investigate here the cooperativity of spastin. Several lines of evidence indicate that interactions among two subunits dominate the cooperative behavior: (i) the ATPase activity shows a sigmoidal dependence on the ATP concentration; (ii) ATPγS displays a mixed-inhibition behavior for normal ATP turnover; and (iii) inactive mutant subunits inhibit the activity of spastin in a hyperbolic dependence, characteristic for two interacting species.

The complex folding network of single calmodulin molecules.

Direct observation of the detailed conformational fluctuations of a single protein molecule en route to its folded state has so far been realized only in silico. We have used single-molecule force spectroscopy to study the folding transitions of single calmodulin molecules. High-resolution optical tweezers assays in combination with hidden Markov analysis reveal a complex network of on- and off-pathway intermediates.

Adenoid reservoir for pathogenic biofilm bacteria.

Biofilms of pathogenic bacteria are present on the middle ear mucosa of children with chronic otitis media (COM) and may contribute to the persistence of pathogens and the recalcitrance of COM to antibiotic treatment. Controlled studies indicate that adenoidectomy is effective in the treatment of COM, suggesting that the adenoids may act as a reservoir for COM pathogens. To investigate the bacterial community in the adenoid, samples were obtained from 35 children undergoing adenoidectomy for chronic OM or obstructive sleep apnea.