Science 345(6195), 346(6212), 347(6220)
- Host genetic diversity enables Ebola hemorrhagic fever pathogenesis and resistance
Studies of the ebola hemorrhagic fever pathogenesis in mouse models have been limited and hindered by that fact that the virus does not cause hemorrhagic symptoms despite causing lethal disease. Thus the pathogenesis studies have been restricted to guinea pigs, macaques and Syrian hamsters, the use of which are limited by ethical and practical difficulties. In this paper, the authors studied the role of the host genetic factors in ebola virus disease using a genetically diverse panel of recombinant inbred (CC-RI) mice. They show that genetic background determines susceptibility to Ebola hemorrhagic fever.
- Strategies for containing ebola in West Africa
The outbreak of Ebola infection since last year in Guinea, Sierra Leone and Liberia, spreading to nearby countries like Nigeria etc has been a global public health emergency situation. It has been imported into countries like United States and Italy as well. Human to human transmission primarily occurs because of contact with body fluids. The lack of adequate facilities just adds woes to the control of the transmission. Moreover, African funeral traditions involve direct contact with the dead body. In the current scenario where there are no proper effective therapeutic treatments and vaccines, it is very important to try curbing the transmission of the virus by non pharmaceutical practices. In this paper, the authors have developed a stochastic model of Ebola transmission between and within the general community, hospitals, and funerals in Liberia. The model was calibrated by using the data obtained from the Liberian Ministry of Health and Social Welfare. They show that a combination of case isolation in the hospital settings, contact-tracing in the community, and sanitary burials must be implemented to achieve a pronounced likelihood of controlling the outbreak over the next 6 months and also in the absence of such multifaceted actions, hundreds of new infections will be arising daily in the following months.
PNAS Volume 111, Number 50 and 51
- Structure of the nonnumeric bacterial amyloid secretion channel
Functional amyloids (curli) secreted by several bacteria helps in biofilm formation, host cell adhesion, and colonization on inert surfaces. In this paper, the authors report the first crystal structure of CsgG, a lipoprotein that forms a secretion channel for curli subunits in the outer membrane. There are four B strands per monomeric unit and in total the entire nonameric channel comprises of a 36 B strand barrel that spans the outer membrane. The channel contains a pore in its centre. The authors have also performed functional and mutational studies to validate the structure based implications for the selective secretion of curli. They show that the curli subunits are secreted as unfolded moieties.
- Type IV pili interactions promote intercellular association and moderate swarming of Pseudomonas aeruginosa
The Flagella and Type IV pilli (TFP) are two devices which confers motility to Pseudomonas aeruginosa. in this paper, the authors studied the role of TFP in swarming using functional assays and computational simulations. The simulations showed that the TFP of the bacteria while swarming should be distributed all over the cell and that TFP-TFP interactions between cells should be a dominant mechanism that promotes cell-cell interaction and inhibition of swarming. This data was supported by additions in vitro experiments which showed that TFP physically inhibits swarming. But the authors did not stress about the atomic level molecular interactions involved in the process.