Summary The social soil bacterium, Myxococcus xanthus, displays a variety of complex and highly coordinated behaviors, including social motility, predatory rippling and fruiting body formation. Here we show that M. xanthus cells produce a network of outer membrane extensions in the form of vesicles and vesicle chains that interconnect cells. We observed peritrichous display of vesicles and vesicle chains and increased abundance in biofilms compared to planktonic cultures. By applying a range of imaging techniques, including 3D Focused Ion Beam Scanning Electron Microscopy (FIB/SEM), we determined these structures to range between 30-60 nm in width and up to 5 μm in length. Purified vesicle chains consist of typical M. xanthus lipids, fucose, mannose, N-acetylglucosamine (GlcNAc) and N-acetylgalactoseamine (GalNAc) carbohydrates and a small set of cargo protein. The protein content includes CglB and Tgl membrane proteins transferred in a contact-dependent manner. Most significantly, the 3D organization of cells within biofilms indicates that cells are connected via an extensive network of membrane extensions that may connect cells at the level of the periplasmic space. Such a network would allow the transfer of membrane proteins and other molecules between cells, and likely provides a mechanism for the coordination of social activities.

The clinical utility of anticoagulation for patients with cirrhosis and asymptomatic portal vein thrombosis (PVT) is widely debated. Complex hemostatic derangements in cirrhosis that increase risk of both bleeding and thrombosis, as well as a lack of randomized controlled data, limit conclusive assessments regarding optimal management of anticoagulation in this setting. In this review, we summarize the relevant literature pertaining to PVT in cirrhosis, including the effect of untreated PVT on the natural progression of liver disease and the overall impact of anticoagulation on clot burden and other relevant clinical outcomes. Apart from patients who are symptomatic or listed for liver transplantation, data supporting anticoagulation for the treatment of PVT is limited and without clear consensus guidelines. In patients with cirrhosis without PVT, emerging evidence for the role of prophylactic anticoagulation to mitigate the progression of fibrosis suggests an optimal risk-benefit tradeoff with decreased rates of liver decompensation and mortality, without a heightened risk of bleeding. In summation, as our understanding of the role of both prophylactic and therapeutic anticoagulation in cirrhosis continues to evolve, ongoing risk stratification of patients with asymptomatic PVT demands further attention.

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