Seismic images of an extensional basin, generated at the hangingwall of a low-angle normal fault: the case of the Sansepolcro basin (Central Italy)

The study of syntectonic basins, generated at the hanging-wall of regional low-angle detachments, can help to gain a better knowledge of these important and mechanically controversial extensional structures, constraining their kinematics and timing of activity. Seismic reflection images constrain the geometry and internal structure of the Sansepolcro Basin (the northernmost portion of the High Tiber Valley). This basin was generated at the hangingwall of the Altotiberina Fault (AtF), an E-dipping low-angle normal fault, active at least since Late Pliocene, affecting the upper crust of this portion of the Northern Apennines. The dataset analysed consists of 5 seismic reflection lines acquired in the 80s’ by ENI-Agip for oil exploration and a portion of the NVR deep CROP03 profile. The interpretation of the seismic profiles provides a 3-D reconstruction of the basin’s shape and of the sedimentary succession infilling the basin. This consisting of up to 1200 m of fluvial and lacustrine sediments: this succession is much thicker and possibly older than previously hypothesised. The seismic data also image the geometry at depth of the faults driving the basin onset and evolution. The western flank is bordered by a set of E-dipping normal faults, producing the uplifting and tilting of Early to Middle Pleistocene succession along the Anghiari ridge. Along the eastern flank, the sediments are markedly dragged along the SW-dipping Sansepolcro fault. Both NE- and SW-dipping faults splay out from the NE-dipping, low-angle Altotiberina fault. Both AtF and its high-angle splays are still active, as suggested by combined geological and geomorphological evidences: the historical seismicity of the area can be reasonably associated to these faults, however the available data do not constrain a unambiguous association between the single structural elements and the major earthquakes

Meiotic double strand breaks repair in sexually reproducing eukaryotes: We are not all equal.

The defining event of meiosis is prophase-I, during which the maternal and paternal chromosome find each other in the nucleus, pair, and align in a process called “synapses of the homologues”. Their faithful segregation during the first meiotic division (MI) requires meiotic recombination and in particular at least one crossing over (CO) per pair of homologous chromosomes. COs are needed, not only to generate diversity within a population, but (along with sister chromatids cohesion) to form the chiasmata that are the physical connection between the homologues that ensures their faithful segregation at metaphase-I. Our understanding of recombination in higher eukaryotes has comes from studies in model organisms such as yeasts, flies and worms. Although there are clear differences among organisms, most of the genes and proteins that are required in these processes are conserved and have orthologues in mammals. However, their null mutations in mice (Mus musculus) do not always display the same phenotype as in lower eukaryotes, indicating that along with the increased complexity of the genome, same genes have acquired new or partially overlapping functions. In this review we will focus on the main genes and protein products which are required for meiotic recombination, comparing the simple metazoan C. elegans and the mouse, underlying divergences and similarities between these organism

Seismic reflection data in the Umbria Marche Region: limits and capabilities to unravel the subsurface structure in a seismically active area

Before seismic data were made available, the subsurface setting of the Umbria-Marche area was mainly derived from the extrapolation of surface data and from models resulting from analogies with other mountain chains around the world. During the ‘90s industrial seismic data availability considerably increased, allowing the definition of new, previously unknown features. Beside the industrial seismic data availability, a deep crustal, near vertical seismic section trending E-W was acquired (CROP-03) across the Italian peninsula from the Tyrrhenian to the Adriatic coast. The subsurface data defined the compressional deformation style (thin- Vs thick- skinned) and the extensional deformation style. A set of east-dipping low-angle-normal faults, which dissect the previous compressional structures and which are the dominant features controlling the extension of the Apennines were recognised. The subsequent application of the seismic data interpretation to seismotectonic issues, defined in more detail the subsurface geometries of the active faults and the relationships between upper crust structure and seismicity

Male infertility due to germ cell apoptosis in mice lacking the thiamin carrier, Tht1. A new insight into the critical role of thiamin in spermatogenesis.

A mouse model of thiamin-responsive megaloblastic anemia (diabetes mellitus, deafness, megaloblastic anemia) lacking functional Slc19a2 has been generated and unexpectedly found to have a male-specific sterility phenotype. We describe here the characterization of the testis-specific effects of absence of the high-affinity thiamin transporter, Tht1. Null males were found to have hypoplastic testes secondary to germ cell depletion. Morphologic and expression analysis revealed that under conditions of standard thiamin intake, tissues affected in the syndrome (pancreatic beta-cell, hematopoietic cells, auditory nerve) maintained normal function but pachytene stage spermatocytes underwent apoptosis. Under conditions of thiamin challenge, the apoptotic cell loss extended to earlier stages of germ cells but spared Sertoli cells and Leydig cells. Injection of high-dose thiamin was effective in reversing the spermatogenic failure, suggesting that the absence of the thiamin carrier could be overcome by diffusion-mediated transport at supranormal thiamin concentrations. These observations demonstrated that male germ cells, particularly those with high thiamin transporter expression beyond the blood-testis barrier, were more susceptible to apoptosis triggered by intracellular thiamin deficiency than any other tissue type. The findings described here highlight an unexpected and critical role for thiamin transport and metabolism in spermatogenesis

Structural comparison of a 15 residue peptide from the V3 loop of HIV-1IIIb and an O-glycosylated analogue

AbstractAs part of a program to study the effect of glycosylation on the three-dimensional structures of HIV-1IIIB V3 peptide constructs, we have examined the solution structures of a 15 residue peptide (RIQRGPGRAFVTIGK, P18IIIB), originally mapped as an epitope recognized by CD8+ Dd class I MHC-restricted murine cytotoxic T-lymphocytes (CTL), and an analogue (P18IIIB-g), O-glycosylated with an α-galactosamine on Thr-12, using NMR, circular dichroism and molecular modeling methods. Our studies show that the peptides sample mainly random conformations in aqueous solution near 25°C and become more ordered by the addition of trifluoroethanol. Upon decreasing the temperature to 5°C, a reverse turn is formed around the immunodominant tip (G5−R8). Glycosylation on T12 ‘tightens’ the turn slightly as suggested by NOE and CD analysis. In addition, the sugar has a defined conformation with respect to the peptide backbone and influences the local peptide conformation. These data suggest that simple glycosylation may influence the conformational equilibrium of a V3 peptide which contains a domain critical for antibody recognition and virus neutralization. We also show that the ability of cytotoxic T-lymphocytes (CTL) to lyse tumor cells presenting P18IIIB was completely abrogated by threonine glycosylation

SEISMIC ANISOTROPY AND MICRO-SEISMICITY IN THE UPPER CRUST AT NORTH OF GUBBIO BASIN (CENTRAL ITALY): RELATION WITH THE SUBSURFACE GEOLOGICAL STRUCTURES AND THE ACTIVE STRESS FIELD

During the months of April and May 2010, a seismic sequence (here named “Pietralunga seismic sequence”) took place in the northeastern part of the Gubbio basin (Northern Apennines); this area is well known to be interested by a continuous background micro-seismic activity. The sequence was recorded both by the INGV National Seismic Network, and by the stations installed by the Project “AIRPLANE” (financially supported by MIUR-Italian Ministry of Education and Research) with the aim of investigating the seismogenetic processes in the Alto Tiberina Fault (ATF) system region. In this work we present the anisotropic results at four stations: ATFO, ATPC, ATPI, ATVO located around the northern termination of the Gubbio basin that well delimit both the seismic se- quence and the whole 2010 seismicity (about 2500 events). The study of seismic anisotropy has provided useful information for the interpretation and evaluation of the stress field and active crustal deformation. Seismic anisotropy can yield valuable information on upper crustal structure, fracture field, and presence of fluid-saturated rocks. Moreover, the large number of seismic waveforms recorded especially during the Pietralunga sequence allows us also to study the spatio-temporal changes of anisotropic parameters to better understand its evolution and the possible correlation to the presence and migration of fluids

To be or not to be a germ cell: The extragonadal germ cell tumor paradigm

In the human embryo, the genetic program that orchestrates germ cell specification in-volves the activation of epigenetic and transcriptional mechanisms that make the germline a unique cell population continuously poised between germness and pluripotency. Germ cell tumors, neo-plasias originating from fetal or neonatal germ cells, maintain such dichotomy and can adopt either pluripotent features (embryonal carcinomas) or germness features (seminomas) with a wide range of phenotypes in between these histotypes. Here, we review the basic concepts of cell specification, migration and gonadal colonization of human primordial germ cells (hPGCs) highlighting the analogies of transcriptional/epigenetic programs between these two cell types

Pyomyositis associated with abscess formation caused by streptococcus pneumoniae in children: a case report and review of literature

Background: Pyomyositis is an unusual bacterial infection but potential severe in children. Staphylococcus Aureus is the main caused of this disease (70–90%), following by Streptococcus Pyogenes (4–16%). Streptococcus Pneumoniae rarely caused invasive muscular infections. We describe a case of pyomyositis caused by Streptococcus Pneumonia in an adolescent 12-year-old female. Case presentation: I.L. referred to our hospital for high fever associated with right hip and abdominal pain. The blood exams showed increase of leukocytes with prevalence of neutrophils with high level of inflammatory markers (CRP 46,17 mg/dl; Procalcitonin 25,8 ng/ml). The abdomen ultrasonography was unremarkable. The CT and MRI of the abdomen and right hip revealed pyomyositis of the iliopsoas, piriformis and internal shutter associated with collection of pus between the muscular planes (Fig. 1). The patient was admitted to our paediatric care unit, and she was initially treatment with intravenous Ceftriaxone (100 mg/kg/day) and Vancomycin (60 mg/kg/day). On day 2, a pansensitive Streptococcus Pneumoniae was isolated from the blood culture, and the antibiotic treatment was changed to only IV Ceftriaxone. She was successively treated with IV Ceftriaxone for 3 weeks, then continued with oral Amoxicillin for a total of 6 weeks of therapy. The follow up showed a complete resolution of the pyomyositis and psoas abscess after 2 months. Conclusion: Pyomyositis associate with abscess is a rare and very dangerous disease in children. The clinical presentation can mimic symptoms of other pathologies like osteomyelitis or septic arthritis, so many times is hard to identify. The main risk factors include story of recent trauma and immunodeficiency, not present in our case report. The therapy involves the antibiotics and, if possible, abscess drainage. In literature there is much discussion about duration of antibiotic therapy