Tufts University

About: Tufts University is a education organization based out in Medford, Massachusetts, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 32800 authors who have published 66881 publications receiving 3451152 citations. The organization is also known as: Tufts College & Universitatis Tuftensis.

Mutations in Col4a1 cause perinatal cerebral hemorrhage and porencephaly.

Abstract: Porencephaly is a rare neurological disease, typically manifest in infants, which is characterized by the existence of degenerative cavities in the brain. To investigate the molecular pathogenesis of porencephaly, we studied a mouse mutant that develops porencephaly secondary to focal disruptions of vascular basement membranes. Half of the mutant mice died with cerebral hemorrhage within a day of birth, and ∼18% of survivors had porencephaly. We show that vascular defects are caused by a semidominant mutation in the procollagen type IV α 1 gene (Col4a1) in mice, which inhibits the secretion of mutant and normal type IV collagen. We also show that COL4A1 mutations segregate with porencephaly in human families. Because not all mutant mice develop porencephaly, we propose that Col4a1 mutations conspire with environmental trauma in causing the disease.

Multiple substrates of the Legionella pneumophila Dot/Icm system identified by interbacterial protein transfer

Abstract: Legionella pneumophila is an intracellular pathogen that multiplies in a specialized vacuole within host cells. Biogenesis of this vacuole requires the Dot/Icm type IV protein translocation system. By using a Cre/loxP-based protein translocation assay, we found that proteins translocated by the Dot/Icm complex across the host phagosomal membrane can also be transferred from one bacterial cell to another. The flexibility of this system allowed the identification of several families of proteins translocated by the Dot/Icm complex. When analyzed by immunofluorescence microscopy, a protein identified by this procedure, SidC, was shown to translocate across the phagosomal membranes to the cytoplasmic face of the L. pneumophila phagosome. The identification of large numbers of these substrates, and the fact that the absence of any one substrate rarely results in strong defects in intracellular growth, indicate that there is significant functional redundancy among the Dot/Icm translocation targets.

Mechanisms of silk fibroin sol-gel transitions.

Abstract: Silk fibroin sol−gel transitions were studied by monitoring the process under various physicochemical conditions with optical spectroscopy at 550 nm. The secondary structural change of the fibroin from a disordered state in solution to a β-sheet-rich conformation in the gel state was assessed by FTIR and CD over a range of fibroin concentrations, temperatures, and pH values. The structural changes were correlated to the degree of gelation based on changes in optical density at 550 nm. No detectable changes in the protein secondary structure (FTIR, CD) were found up to about 15% gelation (at 550 nm), indicating that these early stages of gelation are not accompanied by the formation of β-sheets. Above 15%, the fraction of β-sheet linearly increased with the degree of gelation. A pH dependency of gelation time was found with correlation to the predominant acidic side chains in the silk. Electrostatic interactions were related to the rate of gelation above neutral pH. The overall independencies of processing...