Two structurally different oomycete lipophilic microbe-associated molecular patterns induce distinctive plant immune responses.

Plants recognize a variety of external signals and induce appropriate mechanisms to increase their tolerance to biotic and abiotic stresses. Precise recognition of attacking pathogens and induction of effective resistance mechanisms are critical functions for plant survival. Some molecular patterns unique to a certain group of microbes, microbe-associated molecular patterns (MAMPs), are sensed by plant cells as nonself molecules via pattern recognition receptors. While MAMPs of bacterial and fungal origin have been identified, reports on oomycete MAMPs are relatively limited. This study aimed to identify MAMPs from an oomycete pathogen Phytophthora infestans, the causal agent of potato late blight. Using reactive oxygen species (ROS) production and phytoalexin production in potato (Solanum tuberosum) as markers, two structurally different groups of elicitors, namely ceramides and diacylglycerols, were identified. P. infestans ceramides (Pi-Cer A, B, and D) induced ROS production, while diacylglycerol (Pi-DAG A and B), containing eicosapentaenoic acid (EPA) as a substructure, induced phytoalexins production in potato. The molecular patterns in Pi-Cers and Pi-DAGs essential for defense induction were identified as 9-methyl-4,8-sphingadienine (9Me-Spd) and 5,8,11,14-tetraene-type fatty acid (5,8,11,14-TEFA), respectively. These structures are not found in plants, but in oomycetes and fungi, indicating that they are microbe molecular patterns recognized by plants. When Arabidopsis (Arabidopsis thaliana) was treated with Pi-Cer D and EPA, partially overlapping but different sets of genes were induced. Furthermore, expression of some genes is upregulated only after the simultaneous treatment with Pi-Cer D and EPA, indicating that plants combine the signals from simultaneously recognized MAMPs to adapt their defense response to pathogens.

The Case of IgG4-related Ophthalmic Disease Accompanied by Compressive Optic Neuropathy.

A 76-year-old woman was diagnosed with thyroid-associated orbitopathy (TAO) associated with hypothyroidism at another clinic. Magnetic resonance imaging showed enlargements of the extraocular muscles. Because her best-corrected visual acuity (BCVA) was 0.01OD, she was referred to the Chiba University Hospital. She had an elevation of serum IgG4. She was diagnosed with possible IgG4-related ophthalmic disease (IgG4-ROD) accompanied by optic nerve compression with the mass. She underwent methylprednisolone pulse therapy, and, two months later, her BCVA and visual field defect were greatly improved. Our findings indicate that ophthalmologists should be aware that IgG4-ROD can be masked by lesions associated with TAO.

Case of Orbital Mucosa-Associated Lymphoid Tissue Lymphoma Associated with Serous Retinal Detachment.

We present a case of orbital mucosa-associated lymphoid tissue (MALT) lymphoma accompanied by a serous retinal detachment (SRD). A 44-year-old man who developed uveitis accompanied by a SRD in the right eye was referred to the Chiba National Hospital. B-mode ultrasonography and magnetic resonance imaging (MRI) showed a thickened choroidal membrane and a retrobulbar mass. Although topical steroid treatments improved the inflammation, the SRD did not improve. He was then referred to the Chiba University Hospital. Two months later, the retrobulbar mass had increased, and a partial resection biopsy combined with flow cytometry was performed. The final diagnosis was MALT lymphoma. After R-CHOP (rituximab-cyclophosphamide, doxorubicin, vincristine, and prednisolone) chemotherapy, signs of the tumour could not be detected and the SRD was reduced. We conclude that the SRD was most likely due to the infiltration of lymphoma cells and also to choroidal circulatory disturbances. Retrobulbar malignant lymphomas associated with a SRD are very rare and difficult to diagnosis without biopsy, but because early diagnosis is helpful in deciding the appropriate therapy, we recommend partial biopsy.