Bacterial sexuality is confusing, even for experts! I used to be such an expert on one mechanism of sexuality, conjugation, but that was over 30 years ago. At that time, extra-chromosomal elements, so-called plasmids, were known to encode multiple proteins that together enabled cell-to-cell contacts, which were then used to transfer single-stranded DNA from donor to recipient, thus providing th...

The mechanism of conjugal transfer of plasmids in Gram-negative and unicellular Gram-positive bacteria is commonly via a type IV secretion system (T4SS) [1]. The genes encoding the T4S proteins are usually arranged in a single operon or a few operons. In Gram-negative Agrobacterium tumefaciens, the T4SS is encoded by the virB and virD operons (11 and 5 genes, respectively) [2]. Streptomyces are...

Ehrlichia chaffeensis has type 1 and 4 secretion systems (T1SS and T4SS), but the substrates have not been identified. Potential substrates include secreted tandem repeat protein (TRP) 47, TRP120, and TRP32, and the ankyrin repeat protein, Ank200, that are involved in molecular host-pathogen interactions including DNA binding and a network of protein-protein interactions with host targets assoc...

Brucella Cu-Zn superoxide dismutase (Cu-Zn SOD) is a periplasmic protein, and immunization of mice with recombinant Cu-Zn SOD protein confers protection against Brucella abortus infection. However, the role of Cu-Zn SOD during the process of Brucella infection remains unknown. Here, we report that Cu-Zn SOD is secreted into culture medium and is translocated into host cells independent of type ...

Ehrlichia chaffeensis is a tick-transmitted monocytic ehrlichiosis agent primarily causing the disease in people and dogs. We recently described development characterization of 55 random mutations E. , which aided defining critical nature many bacterial genes for its growth physiologically relevant canine infection model. In current study, we tested 45 mutants their infectivity ability to patho...

Agrobacterium tumefaciens is a phytopathogenic bacterium that causes crown gall disease by transferring transferred DNA (T-DNA) into the plant genome. The translocation process is mediated by the type IV secretion system (T4SS) consisting of the VirD4 coupling protein and 11 VirB proteins (VirB1 to VirB11). All VirB proteins are required for the production of T-pilus, which consists of processe...