Tilapia lake virus causes mitochondrial damage: a proposed mechanism that leads to extensive death in fish cells.

Background: Tilapia lake virus (TiLV), also known as Tilapinevirus tilapiae, poses a significant threat to tilapia aquaculture, causing extensive mortality and economic losses. Understanding the mechanisms and pathogenesis of TiLV is crucial to mitigate its impact on this valuable fish species. Methodology: In this study, we utilized transmission electron microscopy to investigate the ultrastructural changes in E-11 cells following TiLV infection. We also examined the presence of TiLV particles within the cells. Cellular viability and mitochondrial functions were assessed using MTT and ATP measurement assays and mitochondrial probes including JC-1 staining and MitoTracker™ Red. Results: Our findings provide novel evidence demonstrating that TiLV causes cytotoxicity through the destruction of mitochondria. Transmission electron micrographs showed that TiLV particles were present in the cytoplasm of E-11 cells as early as 1 h after infection. Progressive swelling of mitochondria and ultrastructural damage to the cells were observed at 1, 3 and 6 days post-infection. Furthermore, losses of mitochondrial mass and membrane potential (MMP) were detected at 1 day after TiLV inoculation, as determined by mitochondrial probes. The results of the MTT assay also supported the hypothesis that the cell deaths in E-11 cells during TiLV infection may be caused by the disruption of mitochondrial structure and function. Conclusions: Our study reveals the significant role of mitochondrial disruption in contributing to cellular death during the early stages of TiLV infection. These findings advance the understanding of TiLV pathogenesis and further enhance our knowledge of viral diseases in fish.

Case report: Thromboembolic heartworm induced lower limb necrosis in a dog.

A 9-year-old spayed female boxer suffered from lameness in both hindlimbs with a perforated paw wound. Additionally, a linear, worm-like creature was penetrating out from the wound. On examination, the dog was emaciated and infected with heartworms, detected through a fresh blood smear, echocardiography, and transabdominal ultrasonography. Adult heartworms were detected at the right atrium (RA), right ventricle (RV), and pulmonary artery (PA), including the distal abdominal aorta, external iliac, and femoral arteries. During the surgery, adults heartworms were removed from both the heart (n = 8) and the femoral arteries (n = 5). Unfortunately, not all heartworms could be removed from these locations due to the extent of the heartworm infection. The opened, ischemic wounds in the distal limbs progressively expanded and the dog subsequently died, possibly due to caval syndrome complications and septicemia. The necropsy showed no evidence of an atrial septal defect, and a total of 25 adult heartworms were collected from the perforated paw, heart, pulmonary, and femoral arteries. All worms collected during the necropsy process were molecularly confirmed to be Dirofilaria immitis.

Crucial factor causing collapse and aggregation of cultured cells in epon resin.

Ultrastructural artifacts regarding collapse and aggregation of cultured cells have been problematic, especially when investigated apoptotic cells. The infiltration process during sample preparation is considered to be the most crucial factor for this problem. This study was conducted using two culture systems: a suspension culture system of human T-lymphocyte Jurkat cells and rabbit mature dendritic cells and a monolayer culture system of human lung macrophages, human breast cancer cells (A-546 cells) and cat bone-invasive gingival cancer cells (sccf3 cells). Fixation was conducted prior to removing or detaching the cells from the culture dishes. Initial infiltration with a 1 : 3 volume ratio of epon resin : propylene oxide was found to be the most crucial step among these cultured cells. The improved epon-resin infiltration method could eliminate the artifacts. Thus, differentiation between artifactual images and true images is highly possible.

H2O2 activates ryanodine receptor but has little effect on recovery of releasable Ca2+ content after fatigue.

We studied whether hydrogen peroxide (H(2)O(2)) at