Mechanisms of Spirodela polyrhiza tolerance to FGD wastewater-induced heavy-metal stress: Lipidomics, transcriptomics, and functional validation.

Unlike terrestrial angiosperm plants, the freshwater aquatic angiosperm duckweed (Spirodela polyrhiza) grows directly in water and has distinct responses to heavy-metal stress. Plantlets accumulate metabolites, including lipids and carbohydrates, under heavy-metal stress, but how they balance metabolite levels is unclear, and the gene networks that mediate heavy-metal stress responses remain unknown. Here, we show that heavy-metal stress induced by flue gas desulfurization (FGD) wastewater reduces chlorophyll contents, inhibits growth, reduces membrane lipid biosynthesis, and stimulates membrane lipid degradation in S. polyrhiza, leading to triacylglycerol and carbohydrate accumulation. In FGD wastewater-treated plantlets, the degraded products of monogalactosyldiacylglycerol, primarily polyunsaturated fatty acids (18:3), were incorporated into triacylglycerols. Genes involved in early fatty acid biosynthesis, ß-oxidation, and lipid degradation were upregulated while genes involved in cuticular wax biosynthesis were downregulated by treatment. The transcription factor gene WRINKLED3 (SpWRI3) was upregulated in FGD wastewater-treated plantlets, and its ectopic expression increased tolerance to FGD wastewater in transgenic Arabidopsis (Arabidopsis thaliana). Transgenic Arabidopsis plants showed enhanced glutathione and lower malondialdehyde contents under stress, suggesting that SpWRI3 functions in S. polyrhiza tolerance of FGD wastewater-induced heavy-metal stress. These results provide a basis for improving heavy metal-stress tolerance in plants for industrial applications.

Guillain-Barré syndrome complicating early pregnancy: a case report from Nepal.

Guillain-Barré syndrome (GBS) is an immunological demyelinating disorder characterized by progressive, ascending flaccid weakness, usually resulting after infection or some immune stimulation. Its occurrence during pregnancy is rare and due to attribution of its symptoms to pregnancy, diagnosis might be delayed. Case Presentation: A 39-year-old G4P3L2A0 woman at 13 weeks 6 days period of gestation presented with acute, symmetrical, ascending type of flaccid quadriparesis leading to slurring of speech, swallowing difficulty, and eventually respiratory failure. With the diagnosis of GBS, she was admitted to the intensive care unit, five sessions of plasma exchange were done along with physiotherapy and her symptoms started improving. After discharge she was on regular antenatal care visits and eventually, she delivered a healthy baby at term with an uneventful labor event and postpartum period. Clinical Discussion: There is a huge maternal-fetal risk of respiratory failure, aspiration pneumonia, preterm delivery, possible use of forceps or vacuum, and operative interference due to GBS in pregnancy, whose causative agents are similar to that of the general population. The swinging pattern of risk of GBS in pregnancy might be due to immunological changes with predominant Th2 response seen in pregnancy. Treatment measures are similar as in the general population with initial symptomatic care and administration of disease-specific therapy later which consists of intravenous immunoglobulin and/or plasmapheresis. Conclusion: A well-timed diagnosis of GBS in pregnancy might allow successful management with the help of intensive monitoring with or without immunotherapy.