Environmental adaptation of Francisella tularensis

Concerns over weaponizable bacteria have recently prompted considerable interest in Francisella tularensis (Ft). In addition to its potential illicit use, Ft occurs naturally in diverse ecological niches including mammals, arthropods, and fresh water protozoans. Here we review the current knowledge of Ft adaptation which has ramifications for both basic and applied research.     

Stimulation of cyclic AMP and lipolysis in adipose tissue of normal and obese Avy/a mice by LY79771, a phenethanolamine,and stereoisomers

The stimulation of cyclic AMP and lipolysis by LY79771, a phenethanolamine antiobesity compound, and its 3 stereoisomers in adipose tissue of obese viable yellow mice and normal mice were studied. Both activities were stereo-specific with LY79771, the R,S isomer, and LY79730, the R,R isomer, being more potent than LY103085, the S,S isomer, and LY103672, the S,R isomer. Propranolol, a nonspecific β-antagonist, completely inhibited the elevation of cyclic AMP and lipolysis whereas atenolol, a specific β₁ antagonist, inhibited the elevation of cyclic AMP but did not completely inhibit lipolysis. These findings indicate that the elevation of cyclic AMP was mediated by the β₁- receptor whereas the stimulation of lipolysis was mediated by both the β₁ and β₂ receptors. The adipose tissue of the obese viable yellow mice responded to these compounds less than that of the normal mice.     

Persistent mechanical linkage between sister chromatids throughout anaphase

In budding yeast, we have found that sister rDNA arrays marked with fluorescent probes can be visualized as two distinguishable strands during metaphase. Upon anaphase, these arm loci are drawn into the spindle, where they adopt a cruciform-like structure and stretch 2.5-fold as they migrate to the poles. Therefore, while sister rDNA arrays appear separated in metaphase, mechanical linkages between sister arm loci persist throughout anaphase in yeast, as shown in grasshopper spermatocytes (Paliulis and Nicklas 2004). These linkages are partially dependent on the protector of cohesin, SGO1. In anaphase, the spatially regulated dissolution of these mechanical linkages serves to prevent premature sister separation and restrain the rate of spindle elongation. Thus, sister separation is temporally controlled and linkages between sister chromatids contribute to the regulation of anaphase spindle elongation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.