Human enteric adenovirus Ad41 is associated with children gastroenteritis. To infect gastrointestinal cells, the invading virus must be acid-stable and resistant to inactivation by bile salts and proteases. In addition, it has to cross the mucus barrier before it infects mucosa cells. We show that Ad41 infectivity is not diminished by acid exposure, a condition limiting the infectivity of the respiratory Ad. This feature can be attributed to a large extent to the global basic charge of enteric Ad virions and to the stability of Ad41 fiber, a viral protein mediating virus attachment. Upon exposure to pH shock, the respiratory Ad2 loses its ability to interact with lipids while enteric Ad41 still binds to the major phospholipids of gastric and intestine mucus. In addition, contrary to respiratory Ad, enteric Ad41 interacts with several sphingolipid components of plasma membranes. These results show that the molecular bases of the Ad41 enteric tropism stem from its particular physicochemical properties.

Background: Variola virus (family Poxviridae, genusOrthopoxvirus) and the closely related cowpox, vaccinia, and monkeypox viruses can infect humans. Efforts are mounting to replenish the smallpox vaccine stocks, optimize diagnostic methods for poxviruses, and develop new antivirals against smallpox, because it is feared that variola virus might be used as a weapon of bioterrorism. Methods: We developed an assay for the detection of variola virus DNA. The assay is based on TaqMan chemistry targeting the 14-kD protein gene. For the 1st stage of the assay we used genus consensus primers and a mixture of 2 probes (14-kD POX and 14-kD VAR) spanning the 14-kD protein-encoding gene for detection of all human pathogenic orthopoxviruses. We then tested positive samples with the specific orthopoxvirusspecific probe 14-kD POX to identify monkeypox, cowpox, and vaccinia viruses and with the 14-kD VAR probe to identify variola viruses. The assay was established on 4 different PCR cycler platforms. It was assessed in a study with 85 different orthopoxvirus species and strains that included variola, camelpox, cowpox, monkeypox, and vaccinia viruses at concentrations ranging from 100 ng/L to 1 g/L. Results: The assay detected as little as 0.05 fg of DNA, corresponding to 25 copies of DNA, and enabled differentiation of variola virus from the other orthopoxviruses. Conclusions: This real-time PCR assay provides a rapid method for the early detection and differentiation of

Enteric adenoviruses of serotypes 40 and 41 possess some specific structural features, one of which is the presence on the virion of two fibers of different lengths and primary sequences. These viruses are notoriously difficult to grow under laboratory conditions. In this paper the successful growth and purification of Ad41 are presented in detail. Structural Ad41 proteins were analyzed by biochemical methods, mass spectrometry, and electron microscopy (EM), in order to identify and localize them on polyacrylamide denaturing gels and to assess the proportion of short and long fibers in the virion. Surprisingly, the three proteins composing virus short and long pentons did not totally enter the denaturing polyacrylamide gels, which is probably due in part to their high pI. The pentons were separately purified and their dimensions were estimated from EM data. The EM images suggest that there are the same amounts of short and long fibers in each virion.