Agrobacterium tumefaciens can transfer a DNA fragment (T-DNA) from its Ti plasmid to host plant and integrate the T-DNA fragment into host cell nuclear genome. Agrobacterium-mediated T-DNA transfer is the most widely used genetic transformation method for plant. The T-DNA is delivered in the form of single-stranded T-DNA-protein complex (T-complex) by the polar-located Agrobacterium type Ⅳ secretion system (T4SS) to the host cell. T4SS is ancestrally related to bacterial conjugation machines and still used by many plasmids as conjugation channel. Moreover, T4SS is also the secretion channel that used by many human bacterial pathogens to inject the effector proteins to host cells, thus contributing directly to the bacterial pathogenicity. Therefore, in addition to the technical application as a gene vector to create transgenic plants, Agrobacterium-mediated T-DNA transfer also provides a fascinating model system to study the intercellular transfer of macromolecules. The study on the molecular mechanism of T-DNA transfer arouses extensive interest and progresses rapidly in recent years. Here the recent advances in research on T-complex formation and T-complex transfer in Agrobacterium cell are reviewed.

Coronary artery calcifications (CAC) is an independent risk factor for cardiovascular disease (CVD). It has been revealed that this condition can be automatically quantified through computerize tomographic (CT) scan contained in radiotherapy plan for patients with breast cancer, with which, physicians can identify the patients with increased risk of CVD after radiotherapy prematurely and take intervention measures in advance. In this article, the current literature and research progress on the correlation between CAC and cardiotoxicity in patients with breast cancer after radiotherapy were reviewed, expecting to provide a strategy to reduce the CVD risk in patients with breast cancer after radiotherapy.