[Construction and characteristics of a recombinant strain apx II C- /apx I A+ of Actinobacillus pleuropneumoniae serotype 7].

An Actinobacillus pleuropneumoniae apx II C mutant was constructed by transconjugation and counterselection method. Briefly, a transconjugation plasmid pEHA1 was constructed, and transformed into donor strain Escherichia coli 32155. After mixed the donor cells with A .

The key virulence-associated genes of Streptococcus suis type 2 are upregulated and differentially expressed in vivo.

Streptococcus suis causes disease in both pigs and humans. Many virulence genes, including mrp, ef, sly, gapdh, fbps, and hyl, are shown to contribute to S. suis pathogenesis.

Potential use an Actinobacillus pleuropneumoniae double mutant strain DeltaapxIICDeltaapxIVA as live vaccine that allows serological differentiation between vaccinated and infected animals.

Actinobacillus pleuropneumoniae is the causative agent of porcine pleuropneumonia, a highly contagious and often fatal disease. We have previously reported the construction and characterization of a single gene apxIIC deletion mutant HB04C(-) based on A. pleuropneumoniae serovar 7 which produces ApxII toxin and ApxIV.

Effective small interfering RNAs targeting matrix and nucleocapsid protein gene inhibit influenza A virus replication in cells and mice.

RNA interference (RNAi) is a powerful tool to silence gene expression. Small interfering RNA (siRNA)-induced RNA degradation has been recently used as an antivirus agent to inhibit specific virus replication. Here, we showed that several siRNAs specific for conserved regions of influenza virus matrix (M2) and nucleocapsid protein (NP) genes could effectively inhibit expression of the corresponding viral protein.

Construction and immunogencity of a DeltaapxIC/DeltaapxIIC double mutant of Actinobacillus pleuropneumoniae serovar 1.

The apxIC and apxIIC genes of the Actinobacillus pleuropneumoniae serovar 1 strain SLW01, encoding the ApxI- and ApxII-activating proteins, respectively, were deleted successively by a method involving sucrose counterselection. The resulting strain, SLW03, contained no foreign DNA and could secrete unactivated ApxIA and ApxIIA RTX toxins with complete antigenicity. Strain SLW03 was attenuated at least 1000-fold in Balb/C mice and caused no adverse effects in pigs at doses of up to 1 x 10(9) CFU mL(-1).