Synchronous germination and outgrowth of fractionated Bacillus subtilis spores: tool for the analysis of differentiation and division of bacterial cells

A fraction of Bacillus subtilis 168 spores, purified by Urografin isopycnic density centrifugation, heat activated, and inoculated in nutrient broth plus glucose, germinated and outgrew very synchronously. Synchrony was documented by nuclear staining and fluorescence microscopy, and by determining the variation of the buoyant density of the cells during outgrowth. Cell mass increased at constant rates and the passage from one rate to the next was dependent upon deoxyribonucleic acid (DNA) synthesis. DNA synthesis inhibitors induced the formation of anucleated sister cells in a vast majority of the population, indicating that septation was programmed and became independent from DNA synthesis very early in the cell cycle

Presence and role of HLA-C in HIV-1 infection

A whole genome association study reported a SNP at -35Kb from the HLA-C gene strongly associated to HIV-1 viral set point and HLAC expression level (Fellay J. et al., 2007). HLA-C is not down-modulated by HIV-1 Nef and can be specifically incorporated in viral membrane enhancing infectivity and resistance to neutralizing antibodies (Cosma A. et al., 1999). We investigated the role of HLA-C in modulating HIV-1 infectivity using cell fusion and pseudovirus infection models and the interaction between HLA-C and Env at membrane level and in purified fusion complexes

Anti HLA antibodies associated with resistance to HIV infection

Una nuova lettura del De pictura di Leon Battista Alberti Workshop organizzato da Tanja Michalsky e Pietro Roccasecca 13 marzo 2017 Villino Stroganoff Via Gregoriana 22  00187 Roma Il De pictura è il primo testo moderno a trattare sistematicamente tutte le conoscenze necessarie alla rappresentazione visiva dei corpi umani, dell’architettura e della natura al fine di narrare una storia con linee e colori su una superficie. Per questa ragione esso è stato la pietra angolare su cui si sono fonda..

HLA-C is necessary for optimal HIV-1 infection of human peripheral blood CD4 lymphocytes

The hypothesis that open conformers of HLA-C on target cells might directly exert an effect on their infectability by human immunodeficiency virus (HIV) has been suggested previously. This was tested by exploiting the peculiar specificity of monoclonal antibody (mAb) L31 for HLA-C open conformers to show that normal levels of Env-driven fusion were restored in HLA-C transfectants of a major histocompatibility complex-deleted (fusion-incompetent) cell line. The physiological relevance of this finding is now confirmed in this report, where small interfering RNA (siRNA) technology was used to silence HLA-C expression in peripheral blood lymphocytes (PBLs) from 11 healthy donors. Infectability by HIV (strains IIIB and Bal and primary isolates) was significantly reduced (P=0.016) in silenced cells compared with cells that maintained HLA-C expression in 10 of the 11 PBL donors. Normal infectability was resumed, together with HLA-C expression, when the effect of siRNA interference waned after several days in culture. Additional confirmation of the HLA-C effect was obtained in several assays employing HLA-C-positive and -negative cell lines, a number of HIV strains and also pseudoviruses. In particular, viruses pseudotyped with env genes from HIV strains AC10 and QH0692.42 were assayed on siRNA-silenced lymphocytes from three healthy donors: the differences in infection with pseudoviruses were even higher than those observed in infections with normal viruses