Molecular motion of spin labeled side chains in the C-terminal domain of RGL2 protein: a SDSL-EPR and MD study

Five singly spin labeled side chains at surface sites in the C-terminal domain of RGL2 protein have been analyzed to investigate the general relationship between nitroxide side chain mobility and protein structure. At these sites, the structural perturbation produced by replacement of a native residue with a nitroxide side chain appears to be very slight at the level of the backbone fold. The primary determinants of the nitroxide side chain mobility are backbone dynamics and tertiary interactions. On the exposed surfaces of alpha-helices, the side chain mobility is not restricted by tertiary interactions but appears to be determined by backbone dynamics, while in loop sites, the side chain mobility is even higher. For a better understanding of the changes in the EPR spectral line shape, molecular dynamics simulations were performed and found in agreement with EPR spectral data.     

Losing the Big Picture: How Religion May Control Visual Attention

Despite the abundance of evidence that human perception is penetrated by beliefs and expectations, scientific research so far has entirely neglected the possible impact of religious background on attention. Here we show that Dutch Calvinists and atheists, brought up in the same country and culture and controlled for race, intelligence, sex, and age, differ with respect to the way they attend to and process the global and local features of complex visual stimuli: Calvinists attend less to global aspects of perceived events, which fits with the idea that people''s attentional processing style reflects possible biases rewarded by their religious belief system.     

Calcitriol affects hCG gene transcription in cultured human syncytiotrophoblasts

Background  

In pregnancy, maternal serum concentrations of calcitriol significantly rise as a result of increased renal and placental contribution in order to assure calcium supply for the developing fetus. Considering that placenta is a site for vitamin D activation, and the versatility and potency of calcitriol, it is feasible that this hormone participates in fetal/placental development and physiology. In the present work we studied calcitriol actions upon human chorionic gonadotropin (hCG) secretion and expression in cultured trophoblasts, as well as vitamin D receptor (VDR) and CYP27B1 immunolocalization in placental villi.     

Tight junctions and apical/basolateral polarity

Summary Physiological studies led to devise models of epithelial cells in which the membrane does not have its molecules distributed homogeneously, but polarized towards the apical or towards the basolateral regions. For a while, it was assumed that the TJ, acting as a fence between the two regions, would be responsible for this asymmetry. However, today the information available indicates not only that polarization may proceed independently of the TJ, but that this structure itself may attain its precise location due to a polarization process. Nevertheless, TJs may play a role in restricting to the apical or to the basolateral region those molecules that are free to diffuse in the plane of the cell membrane (e.g., lipids and protein that are not attached to cytoplasmic or extracellular structures).     

Why Lyme disease is common in the northern US,but rare in the south: The roles of host choice,host-seeking behavior,and tick density

Lyme disease is common in the northeastern United States, but rare in the southeast, even though the tick vector is found in both regions. Infection prevalence of Lyme spirochetes in host-seeking ticks, an important component to the risk of Lyme disease, is also high in the northeast and northern midwest, but declines sharply in the south. As ticks must acquire Lyme spirochetes from infected vertebrate hosts, the role of wildlife species composition on Lyme disease risk has been a topic of lively academic discussion. We compared tick–vertebrate host interactions using standardized sampling methods among 8 sites scattered throughout the eastern US. Geographical trends in diversity of tick hosts are gradual and do not match the sharp decline in prevalence at southern sites, but tick–host associations show a clear shift from mammals in the north to reptiles in the south. Tick infection prevalence declines north to south largely because of high tick infestation of efficient spirochete reservoir hosts (rodents and shrews) in the north but not in the south. Minimal infestation of small mammals in the south results from strong selective attachment to lizards such as skinks (which are inefficient reservoirs for Lyme spirochetes) in the southern states. Selective host choice, along with latitudinal differences in tick host-seeking behavior and variations in tick densities, explains the geographic pattern of Lyme disease in the eastern US.

Lyme disease is common in the northeastern United States, but rare in the southeast, even though the tick vector is found in both regions. This study shows that this is largely because the tick vectors attach abundantly to rodents (which are good hosts for the Lyme bacteria) in the north, and to lizards (which are relatively poor hosts for Lyme bacteria) in the south.     

Inducible Amplification of Gene Copy Number and Heterologous Protein Production in the Yeast Kluyveromyces lactis

Heterologous protein production can be doubled by increasing the copy number of the corresponding heterologous gene. We constructed a host-vector system in the yeast Kluyveromyces lactis that was able to induce copy number amplification of pKD1 plasmid-based vectors upon expression of an integrated copy of the plasmid recombinase gene. We increased the production and secretion of two heterologous proteins, glucoamylase from the yeast Arxula adeninivorans and mammalian interleukin-1β, following gene dosage amplification when the heterologous genes were carried by pKD1-based vectors. The choice of the promoters for expression of the integrated recombinase gene and of the episomal heterologous genes are critical for the mitotic stability of the host-vector system.     

The challenge of health care provision: A case study from Mexico

Lorenza Menegoni has a doctorate in Anthropology from the Graduate Faculty, The New School for Social Research, New York City. She is continuing her research in Mexico. Carmen Hendershott has a doctorate in Anthropology from the Graduate Faculty, The New School for Social Research, where she is working as a research librarian.