SPIKE1 Activates the GTPase ROP6 to Guide the Polarized Growth of Infection Threads in Lotus japonicus.

In legumes, rhizobia attach to root hair tips and secrete nodulation factor to activate rhizobial infection and nodule organogenesis. Endosymbiotic rhizobia enter nodule primordia via a specialized transcellular compartment known as the infection thread (IT). The IT elongates by polar tip growth, following the path of the migrating nucleus along and within the root hair cell. Rho-family ROP GTPases are known to regulate the polarized growth of cells, but their role in regulating polarized IT growth is poorly understood. Here, we show that LjSPK1, a DOCK family guanine nucleotide exchange factor (GEF), interacts with three type I ROP GTPases. Genetic analyses showed that these three ROP GTPases are involved in root hair development, but only LjROP6 is required for IT formation after rhizobia inoculation. Misdirected ITs formed in the root hairs of Ljspk1 and Ljrop6 mutants. We show that LjSPK1 functions as a GEF that activates LjROP6. LjROP6 enhanced the plasma membrane localization LjSPK1 in Nicotiana benthamiana leaf cells and Lotus japonicus root hairs, and LjSPK1 and LjROP6 interact at the plasma membrane. Taken together, these results shed light on how the LjROP6-LjSPK1 module mediates the polarized growth of ITs in L. japonicus.

Hemolytic anemia in alcoholic liver disease: Zieve syndrome: A case report and literature review.

RATIONALE: Zieve syndrome, a rarely reported disease resulting from alcohol abuse, consists of a triad of symptoms: hemolytic anemia, cholestatic jaundice, and transient hyperlipidemia. It is largely under-recognized and under-reported, possibly because of unawareness of the condition by physicians. Here, we report a case of Zieve syndrome managed at the Jilin University First Bethune Hospital. PATIENT CONCERNS: A 30-year-old Chinese woman presented with a 4-month history of fatigue, yellowish discoloration of the eyes, and tea-colored urine. She had been a heavy drinker for 2 years prior to onset of the disease with an average daily alcohol intake of 60 g/d and more than 80 g/d for the previous 6 months. DIAGNOSIS: The diagnosis of Zieve syndrome was confirmed based on hemolysis and cholestatic jaundice secondary to alcoholic liver disease and heavy drinking. Bone marrow biopsy and liver biopsy both supported the diagnosis. INTERVENTIONS: We treated her with abstinence from alcohol and supportive therapy. OUTCOMES: The patient was discharged 14 days after admission with an improvement in symptoms, which continued to subside during the 2-month follow-up period. LESSONS: Doctors confronted with hemolysis in a patient with alcoholic liver disease should be aware of the under-reported Zieve syndrome. Recognition of this syndrome could help doctors avoid unnecessary invasive procedures and emphasize the importance of alcohol abstinence as the mainstay of management. Glucocorticoids may not be useful in treating hemolytic anemia in Zieve syndrome.