PrimPol is required for replicative tolerance of G quadruplexes in vertebrate cells

G quadruplexes (G4s) can present potent blocks to DNA replication. Accurate and timely replication of G4s in vertebrates requires multiple specialized DNA helicases and polymerases to prevent genetic and epigenetic instability. Here we report that PrimPol, a recently described primase-polymerase (PrimPol), plays a crucial role in the bypass of leading strand G4 structures. While PrimPol is unable to directly replicate G4s, it can bind and reprime downstream of these structures. Disruption of either the catalytic activity or zinc-finger of PrimPol results in extreme G4-dependent epigenetic instability at the BU-1 locus in avian DT40 cells, indicative of extensive uncoupling of the replicative helicase and polymerase. Together, these observations implicate PrimPol in promoting restart of DNA synthesis downstream of, but closely coupled to, G4 replication impediments

Twin shaping filter technique for signals compensation in CZT detectors grown by the vertical bridgman method

CdTe/CdZnTe is a consolidated material to realize detectors for a large variety of applications, such as medical, industrial, and space research. An Italian collaboration, involving the CNR/IMEM and INAF/IASF institutes, was born some years ago with the aim to develop a national capability to produce CZT detectors starting from the material growth to the final detection device. Some important features of these detectors (pulse height, energy resolution, photopeak efficiency) are affected by the charge collection efficiency: the low mobility of the charge carriers (particularly the holes) and trapping/detrapping phenomena can degrade the CdTe/CZT detectors response, depending on the distance between the charge formation position and the collecting electrodes. Several efforts have been made to improve the detection efficiency as well as the energy resolution, using both the optimization of the electrode geometry (drift strip technique, coplanar-grid, small pixel effect) and pulse height compensation methods to overcome the hole trapping problem. We have studied a bi-parametric method that uses a twin pulse shaping active filter to analyze the same signal: one slow, which is proportional to the energy of the photon, and one fast, which depends on the position of the interaction with respect to the collecting electrode. The experimental results obtained with the application of this bi-parametric technique on planar CZT detectors of good quality grown by the Vertical Bridgman method at CNR/IMEM are presented as a function of the bias voltage, photon energy and shaping time pairs

A survey on the occurrence of ochratoxin A in feeds and sera collected in conventional and organic poultry farms in Northern Italy

A survey has been conducted on conventional and organic poultry farms located in northern Italy in order to investigate the occurrence of ochratoxin A (OTA) in feeds and sera in 2006. Ten poultry farms were monitored by taking 20 samples of feed and 94 samples of blood. OTA was assessed through immunoaffinity column purification and HPLC analysis. For in-house validation, recovery experiments, carried out on the spiked samples in the range of 1.0-10.0 μg OTA kg-1 and 0.3-3.0 ng OTA ml-1 for the feed and serum samples, respectively, led to overall recovery averages of 80.6% (RDS=7.3%, n=9) and 83.3% (RDS=3.1%, n=9), respectively. All the feed samples were contaminated by OTA with values ranging from 0.04 to 6.50 μg kg-1. Fiftythree percent of the sera samples were positive, with values ranging from 0.003- 0.165 ng ml-1. None of the feed samples was above the limits set by the European Union on OTA contamination in poultry feeds. No statistically significant differences in OTA contamination of feed or sera were observed either between the organic vs conventional group or between the laying hens vs broiler group