Hyperglycemia-linked oxidative stress and/or consequent endoplasmic reticulum stress are the causative factors of pathogenesis of diabetic retinopathy. Dietary bioactive components which mitigate oxidative stress may serve as potential chemopreventative agents to prevent or slow down the disease progression. Wolfberry is a traditional Asian fruit consumed for years to prevent aging eye diseases in Asian countries. Here we report that dietary wolfberry ameliorated mouse retinal abnormality at the early stage of type 2 diabetes in db/db mice. Male mice at 6 weeks of age were fed the control diet with or without 1 % (kCal) wolfberry for 8 weeks. Dietary wolfberry restored the thickness of the whole retina, in particular the inner nuclear layer and photoreceptor layer, and the integrity of retinal pigment epithelia (RPE), and the ganglion cell number in db/db mice. Western blotting of whole retinal cell lysates revealed that addition of wolfberry lowered expression of endoplasmic reticulum (ER) stress biomarkers BiP, PERK, ATF6, and caspase-12; and restored AMPK, thioredoxin, Mn SOD, and FOXO3α activities. To determine if our observations were due to the high contents of zeaxanthin and lutein in wolfberry additional studies using these carotenoids were conducted. Using the human adult diploid RPE cell line ARPE-19 we demonstrated that both zeaxanthin and lutein could mimic wolfberry preventive effect on activation of AMPK, thioredoxin, Mn SOD, FOXO3α activities, normalize cellular reactive oxygen species, and attenuate ER stress in ARPE-19 cells exposed to a high glucose challenge. The zeaxanthin preventive effect was abolished by siRNA knockdown of AMPKα. These results suggested that AMPK activation appeared to play a key role in upregulated expression of thioredoxin and Mn SOD, and mitigation of cellular oxidative stress and/or ER stress by wolfberry and zeaxanthin and/or lutein. Taken together, dietary wolfberry on retinal protection in diabetic mice is, at least partially, due to zeaxanthin and/or lutein.

The rice bacterial blight pathogen Xanthomonas oryzae pv. oryzae is a vascular pathogen that elicits a defensive response through interaction with metabolically active rice cells. In leaves of 12-day-old rice seedlings, the exposed pit membrane separating the xylem lumen from the associated parenchyma cells allows contact with bacterial cells. During resistant responses, the xylem secondary walls thicken within 48 h and the pit diameter decreases, effectively reducing the area of pit membrane exposed for access by bacteria. In susceptible interactions and mock-inoculated controls, the xylem walls do not thicken within 48 h. Xylem secondary wall thickening is developmental and, in untreated 65-day-old rice plants, the size of the pit also is reduced. Activity and accumulation of a secreted cationic peroxidase, PO-C1, were previously shown to increase in xylem vessel walls and lumen. Peptide-specific antibodies and immunogold-labeling were used to demonstrate that PO-C1 is produced in the xylem parenchyma and secreted to the xylem lumen and walls. The timing of the accumulation is consistent with vessel secondary wall thickening. The PO-C1 gene is distinct but shares a high level of similarity with previously cloned pathogen-induced peroxidases in rice. PO-C1 gene expression was induced as early as 12 h during resistant interactions and peaked between 18 and 24 h after inoculation. Expression during susceptible interactions was lower than that observed in resistant interactions and was undetectable after infiltration with water, after mechanical wounding, or in mature leaves. These data are consistent with a role for vessel secondary wall thickening and peroxidase PO-C1 accumulation in the defense response in rice to X. oryzae pv. oryzae.

Scope Our aim was to investigate whether dietary wolfberry altered carotenoid metabolic gene expression and enhanced mitochondrial biogenesis in the retina of diabetic mice. Methods and Results Six-week-old male db/db and wild type mice were fed the control or wolfberry diets for 8 weeks. At study termination, liver and retinal tissues were collected for analysis by transmission electron microscopy, real-time PCR, immunoprecipitation, Western blot, and HPLC. Wolfberry elevated zeaxanthin and lutein levels in the liver and retinal tissues and stimulated expression of retinal scavenger receptor class B type I, glutathione S-transferase Pi 1, and β,β-carotene 9’,10’-oxygenase 2, and induced activation and nuclear enrichment of retinal AMP-activated protein kinase α2 (AMPKα2). Furthermore, wolfberry attenuated hypoxia and mitochondrial stress as demonstrated by declined expression of hypoxia-inducible factor-1α, vascular endothelial growth factor, and heat shock protein 60. Wolfberry enhanced retinal mitochondrial biogenesis in diabetic retinas as demonstrated by reversed mitochondrial dispersion in the retinal pigment epithelium, increased mitochondrial copy number, elevated citrate synthase activity, and up-regulated expression of peroxisome proliferator-activated receptor γ co-activator 1 α, nuclear respiratory factor 1, and mitochondrial transcription factor A. Conclusion Consumption of dietary wolfberry could be beneficial to retinoprotection through reversal of mitochondrial function in diabetic mice.

Fusobacterium necrophorum, a gram-negative, rod-shaped, anaerobic bacterium, is a primary or secondary etiological agent in a variety of necrotic, purulent infections in humans and animals. Its major virulence factor is leukotoxin, a high-molecular-weight secreted protein, primarily toxic to ruminant leukocytes. In this study, bovine peripheral blood leukocytes were exposed to various concentrations of immunoaffinity-purified leukotoxin and the cytotoxicity was analyzed by flow cytometry and scanning and transmission electron microscopy. At very low toxin concentrations, polymorphonuclear leukocytes (PMNs) showed activation, as indicated by translocation of primary and secondary granules to the periphery of the cytoplasm. Furthermore, these cells showed changes characteristic of apoptosis, including decreased cell size, organelle condensation, cytoplasmic membrane blebbing (zeiosis), and chromatin condensation and margination, and decrease in cellular DNA content. At moderately high concentrations of leukotoxin, bovine mononuclear cells were also induced to undergo programmed cell death. At very high concentrations, leukotoxin caused necrotic cell death of bovine peripheral leukocytes. The ability of F. necrophorum leukotoxin to modulate the host immune system by its toxicity, including cellular activation of PMNs and apoptosis-mediated killing of phagocytes and immune effector cells, represents a potentially important mechanism of its pathogenesis.

Ehrlichia chaffeensis, transmitted from Amblyomma americanum ticks, causes human monocytic ehrlichiosis. It also infects white-tailed deer, dogs and several other vertebrates. Deer are its reservoir hosts, while humans and dogs are incidental hosts. E. chaffeensis protein expression is influenced by its growth in macrophages and tick cells. We report here infection progression in deer or dogs infected intravenously with macrophage- or tick cell-grown E. chaffeensis or by tick transmission in deer. Deer and dogs developed mild fever and persistent rickettsemia; the infection was detected more frequently in the blood of infected animals with macrophage inoculum compared to tick cell inoculum or tick transmission. Tick cell inoculum and tick transmission caused a drop in tick infection acquisition rates compared to infection rates in ticks fed on deer receiving macrophage inoculum. Independent of deer or dogs, IgG antibody response was higher in animals receiving macrophage inoculum against macrophage-derived Ehrlichia antigens, while it was significantly lower in the same animals against tick cell-derived Ehrlichia antigens. Deer infected with tick cell inoculum and tick transmission caused a higher antibody response to tick cell cultured bacterial antigens compared to the antibody response for macrophage cultured antigens for the same animals. The data demonstrate that the host cell-specific E. chaffeensis protein expression influences rickettsemia in a host and its acquisition by ticks. The data also reveal that tick cell-derived inoculum is similar to tick transmission with reduced rickettsemia, IgG response and tick acquisition of E. chaffeensis.