PEGylation of the antimicrobial peptide nisin A: problems and perspectives

Nisin is a natural antimicrobial peptide produced by Lactococcus lactis and widely employed as food preservative. Its low solubility in neutral aqueous solutions, its instability at physiological pH and its rapid breakdown by proteolytic enzymes has limited its use for processed foods (processed cheese, milk and derivatives, canned vegetables). The conjugation to poly(ethylene glycol) (PEG) could improve its solubility and protect it towards enzymes present in non optimally processed food. We report the synthesis of a PEG-nisin conjugate, and the microbiology assays against some bacterial cell lines.     

Measles and rubella eradication in the Americas

The challenge for regions embarking on measles elimination will be to maintain high population immunity with excellent vaccination coverage and high-quality surveillance. Meeting this challenge will be especially critical for dealing with importations of measles virus that will occur as long as the virus is circulating anywhere in the world. Implementation of measles elimination strategies will uncover the "hidden" disease burden of rubella and congenital rubella syndrome. As was the experience in countries of Latin America and the Caribbean (LAC), integrating the elimination of measles with the elimination of rubella will greatly enhance the capacity of countries to sustain progress in the reduction of measles mortality. Countries of LAC prioritized the routine national immunization program over short-term successes. While doing so, they have also encountered new opportunities to expand the benefits of disease control and elimination activities to other aspects of public health, most importantly towards improving health care for women and newborns and reducing inequities in health in the region's poorest communities. Implementation of similar strategies could lead to the global eradication of measles, rubella, and congenital rubella syndrome early this century, while strengthening routine immunization programs, and developing the capacity to introduce new and underutilized vaccines.     

Lysis by natural killer cells requires viral replication and glycoprotein expression

Several lines of evidence suggest that natural killer cells (NK) have an important role in antiviral defense. To be thus effective, NK cells have to recognize and cause lysis of virus-infected cells. The mechanism underlying this interaction was investigated in a murine system using vesicular stomatitis virus (VSV). A large number of cell lines was screened to identify a permissive target for VSV infection and the B16 murine melanoma cells were chosen since VSV replicates in these cells without producing cytopathic effects 24 h after infection. Spontaneous lysis of B16 melanoma cells by spleen cells occurred only if the target cells were previously infected with VSV. Treatment of spleen cells with anti NK 1.1 or anti Thy 1.2 plus complement decreased the specific lysis by 50%, therefore, the phenotype of the effector cells in this system corresponds to the NK cell subset. Immunofluorescent staining with polyclonal and monoclonal anti-VSV antibodies demonstrated that the viral glycoprotein G is abundantly expressed on the target cell surface. Treatment of the VSV-infected targets with tunicamycin prevented glycosylation of newly synthesized VSV glycoprotein G on the cell membrane. This treatment abrogated completely NK-mediated killing of the infected B16 melanoma cells. These results indicate that virus replication and membrane expression of glycosylated protein G are essential for recognition and lysis of VSV-infected targets by NK cells.     

The economic impact of smoke-free laws on sales in bars and restaurants in Argentina

We studied the impact of the recent smoke-free laws on the sales in bars and restaurants, in the city of Buenos Aires and in three provinces of Argentina. Using a quasi-experimental design and a difference-in-differences estimation procedure we found that the smoke-free laws did not have a statistically significant negative effect on sales in bars and restaurants in the city of Buenos Aires and in the provinces of Córdoba, Santa Fe and Tucumán. Moreover, in the case of Buenos Aires, the smoke-free legislation could have induced an increase in the sales in bars and restaurants.     

The effect of long-term ethanol treatment on the polysome profile of brain, liver, and kidneys of mice

Female mice were fed ad libitum with a liquid diet containing5% (w/w) ethanol. After 4–8 weeks the polysome profileof brain, liver and kidneys showed changes indicating an increasedstate of aggregation.