CYP722C from Gossypium arboreum catalyzes the conversion of carlactonoic acid to 5-deoxystrigol.

MAIN CONCLUSION: CYP722C from cotton, a homolog of the enzyme involved in orobanchol synthesis in cowpea and tomato, catalyzes the conversion of carlactonoic acid to 5-deoxystrigol. Strigolactones (SLs) are important phytohormones with roles in the regulation of plant growth and development. These compounds also function as signaling molecules in the rhizosphere by interacting with beneficial arbuscular mycorrhizal fungi and harmful root parasitic plants. Canonical SLs, such as 5-deoxystrigol (5DS), consist of a tricyclic lactone ring (ABC-ring) connected to a methylbutenolide (D-ring). Although it is known that 5DS biosynthesis begins with carlactonoic acid (CLA) derived from ß-carotene, the enzyme that catalyzes the conversion of CLA remains elusive. Recently, we identified cytochrome P450 (CYP) CYP722C as the enzyme that catalyzes direct conversion of CLA to orobanchol in cowpea and tomato (Wakabayashi et al., Sci Adv 5:eaax9067, 2019). Orobanchol has a different C-ring configuration from that of 5DS. The present study aimed to characterize the homologous gene, designated GaCYP722C, from cotton (Gossypium arboreum) to examine whether this gene is involved in 5DS biosynthesis. Expression of GaCYP722C was upregulated under phosphate starvation, which is an SL-producing condition. Recombinant GaCYP722C was expressed in a baculovirus-insect cell expression system and was found to catalyze the conversion of CLA to 5DS but not to 4-deoxyorobanchol. These results strongly suggest that GaCYP722C from cotton is a 5DS synthase and that CYP722C is the crucial CYP subfamily involved in the generation of canonical SLs, irrespective of the different C-ring configurations.

Clinically node-negative invasive lobular carcinoma of the breast showing multiple lymph node metastases.

A 73-year-old woman was pointed out of her right breast tumor on screening computed tomography (CT). Mammography showed distortion of the mammary gland and skin retraction. Ultrasound (US) showed an irregular tumor with hyperechoic haloes adjacent to the anterior tumor borders. Neither lymphadenopathy nor image findings suggesting lymph node metastasis were detected on US and CT. Core needle biopsy pathologically showed the tumor to be invasive lobular carcinoma. Under the preoperative diagnosis of node-negative breast cancer, the patient underwent mastectomy and sentinel node biopsy. Due to no sentinel node detection, a small but hard lymph node was identified and submitted for frozen section as a sampling node. After confirming the lymph node metastasis on frozen section, axillary lymph node dissection revealed 12 lymph node metastases. Postoperative pathological study showed cancer cell infiltration to the dermis near the nipple-areolar complex. In addition, immmunostaining showed the tumor to have low proliferative biology, i.e., Ki-67 labelling index of 10%. Breast surgeons should note that indolent invasive lobular carcinoma with cancer cell infiltration to the skin near the nipple-areolar complex can have multiple lymph node metastases even though showing neither lymphadenopathy nor image findings suggesting lymph node metastasis.

Monomorphic Epitheliotropic Intestinal T-Cell Lymphoma in the Ileum with Successful Preoperative Endoscopic Evaluation.

A 80-year-old man with the history of operations for gastric cancer and adhesive ileus developed abdominal pain. Positron emission computed tomography (CT) showed prominent wall thickening in the ileum with a maximal standardized uptake value of 12.1. Prior CT to diagnose adhesive ileus just taken only 4 months before did not show any masses in the abdomen. Single-balloon enteroscopy via colon showed a protruding mass at approximately 40-50 cm proximal point from the ileum end. Pathological examination of the biopsied specimen showed diffuse infiltration of medium- to large-sized atypical lymphocytes. Immunohistochemistry analysis showed that the atypical cells were positive for CD3 and CD56 and negative for CD8 and CD20. MIB-1 labeling index was extremely high as 80%. Under the diagnosis of intestinal T-cell lymphoma, the patient underwent tumorectomy, leading to the diagnosis of monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) after the negativity confirmation of Epstein-Barr virus-encoded mRNAs. The patient recovered with manageable complication and is going to receive chemotherapy. This is the first case of MEITL with extremely rapid progression in the distal ileum to be observed and diagnosed with single-balloon enteroscopy.