The recent discovery of TA loci in obligatory intracellular species of the Rickettsia genus has prompted new research to establish whether they work as stress response elements or as addiction systems that might be toxic for the host cell. VapBC2 is a TA locus from R. felis, a pathogen responsible for flea-borne spotted fever in humans. The VapC2 toxin is a PIN-domain protein, whereas the antitoxin, VapB2, belongs to the family of swapped-hairpin beta-barrel DNA-binding proteins. We have used a combination of biophysical and structural methods to characterize this new toxin/antitoxin

pair. Our results show how VapB2 can block the VapC2 toxin. They provide a first structural description of the interaction between a swapped-hairpin beta-barrel protein and DNA. Finally, these results Selleckchem CBL0137 suggest how the VapC2/VapB2

molar ratio can control the self-regulation of the TA locus transcription.”
“The inhibitory effect of ultrasound on barnacle AR-13324 (Amphibalanus amphitrite) cyprid was investigated under three excitation frequencies (23, 63, and 102 kHz). The linear regression models were built to study the effect of ultrasound pressure and exposure time on the cyprid settlement. The negative slopes of the linear regression lines indicate reduced settlement behavior with increased exposure time and acoustic pressure. The excitation frequency of 23 kHz was found to be the most effective on settlement inhibition,

with 63 and 102 kHz exhibiting similar but weaker response. Separately, ultrasonic cavitation was investigated and confirmed in the filtered seawater (FSW) and partially degassed filtered seawater (PDFSW) via the acoustic spectrum analysis. The cavitation energy was found to be double in FSW than in PDFSW at 23 kHz with the acoustic pressure of 20 kPa. The much higher settlement click here reduction and stronger cavitation in FSW at 23 kHz suggest that cavitation is a possible if not most likely mechanism for the cyprid inhibition. The cavitation induced force may lead to physical damage to the cyprids which subsequently will result in much higher mortality. The cavitation effect was proven to be stronger at 23 kHz than the other two frequencies with the same acoustic energy, which might explain the enhanced efficiency on settlement reduction at this frequency. (C) 2011 Elsevier B.V. All rights reserved.”
“The present study investigated the effects of chronic pre-exposure to methamphetamine on sexual motivation and performance in male Japanese quail. Quail were pre-exposed to methamphetamine (1.0 or 3.0 mg/kg ip) or saline (ip) once daily for 10 days and locomotor activity was measured. After a 10 day washout period, sexual motivation was measured in a straight-arm runway with visual access to a female at one end.