HIV-1 Capsid Core: A Bullet to the Heart of the Target Cell

The first step of the intracellular phase of retroviral infection is the release of the viral capsid core in the cytoplasm. This structure contains the viral genetic material that will be reverse transcribed and integrated into the genome of infected cells. Up to recent times, the role of the capsid core was considered essentially to protect this genetic material during the earlier phases of this process. However, increasing evidence demonstrates that the permanence inside the cell of the capsid as an intact, or almost intact, structure is longer than thought. This suggests its involvement in more aspects of the infectious cycle than previously foreseen, particularly in the steps of viral genomic material translocation into the nucleus and in the phases preceding integration. During the trip across the infected cell, many host factors are brought to interact with the capsid, some possessing antiviral properties, others, serving as viral cofactors. All these interactions rely on the properties of the unique component of the capsid core, the capsid protein CA. Likely, the drawback of ensuring these multiple functions is the extreme genetic fragility that has been shown to characterize this protein. Here, we recapitulate the busy agenda of an HIV-1 capsid in the infectious process, in particular in the light of the most recent findings.

Effect of soil erosion and topography on distribution of cadmium (Cd) in Sumani watershed, west Sumatra, Indonesia

The purpose of this study was to characterize and present the distribution of heavy metals especially Cd on agricultural and non-agricultural lands and river sediments in relation to soil erosion and topography status in watersheds. The study was conducted for a detailed soil survey by collecting 146 soil sample based on land use, soil family and topography position and 23 river sediments sample. The Cd was extracted by 0.1 M HCl and determined by ICP. The result showed that the concentration of Cd in soil and river sediment were low in toxicity based on FAO recommendation (Cd 0.4 mg/kg) with only 4 out of 169 sampling sites contained Cd exceeding the toxicity level. Volcanic ash from Mount Talang Volcano is a natural source of Cd in Sumani watershed. Cd concentration was low in areas with high soil erosion, which indicate material translocation caused by high soil erosion that accumulates sediment in plains and rivers. Agricultural soil was found to be low in soil pH and clay accompanied by high R factor and upland topography hence the increase in Cd concentration of the soil. The study concluded that Cd abundance in soils may be influenced by soil pH, texture, total carbon, erosion factors, and topography.