Interaction of Pathogenic Vibrio Bacteria With the Blood Clot of the Pacific White Shrimp, Litopenaeus vannamei

Abstract

Abstract.In addition to its roles in hemostasis and wound repair, the blood clot plays an underappreciated role in innate immunity, where the established clot serves as a barrier to microbial penetration into the internal milieu and where the early clot entraps and immobilizes microbes that have entered wounds to the integuments. In this report we document the behavior of the pathogenic gram-negative bacterium Vibrio harveyi that has been entrapped in the fabric of the extracellular blood clot of one of its target organisms, the Pacific white shrimp, Litopenaeus vannamei. The freshly entrapped bacteria are held tightly by the clot, losing even Brownian motility, but by 1 h post-entrapment, a fraction of the bacteria have established small domains of fibrinolysis that enlarge progressively, enabling bacteria to escape from the clot's embrace. Escape is dependent on the actions of both serine-and metallo-proteases released from the bacterial cells.

The architecture of neutrophil extracellular traps investigated by atomic force microscopy

“…55 However, it is common for microorganisms to secrete extracellular proteases which help them to obtain amino acids through the degradation of a variety of substrates found in their environment. 56 Extracellular proteases have been shown to help bacteria evade blood clots 54,57 and in degrading immune system components. 58 Intracellular pathogens, such as Chlamydia trachomatis, can produce histone-specific proteases 59 which could play a role in the extracellular environment and in the presence of NETs.…”

Three-dimensional quantitative phase imaging of blood coagulation structures by optical projection tomography in flow cytometry using digital holographic microscopy

“…[1][2][3][4][5][6][7][8][9][10] An observation of RBCs and blood coagulation structures using microscopic techniques is useful for biomedical imaging of cell morphology, and therefore cell imaging methods in various types of microscopies are proposed, such as electron microscopy, 7 atomic force microscopy, 8 confocal optical microscopy, 9 and conventional optical microscopy. 10 Although electron and atomic force microscopies realize the 3-D imaging with a high spatial resolution, these microscopies are invasive to biological cells, have the small field of view, and need to perform a scanning process with time consumption, which means that it is difficult to realize the real-time measurements in these microscopies. A confocal microscopy can observe biological cells noninvasively, but it has the same disadvantages in the field of view and in the acquisition time of the 3-D information as the electron and atomic force microscopies.…”