Diacylglyceryl-N,N,N-trimethylhomoserine-dependent lipid remodeling in a green alga, Chlorella kessleri.

Membrane lipid remodeling contributes to the environmental acclimation of plants. In the green lineage, a betaine lipid, diacylglyceryl-N,N,N-trimethylhomoserine (DGTS), is included exclusively among green algae and nonflowering plants. Here, we show that the green alga Chlorella kessleri synthesizes DGTS under phosphorus-deficient conditions through the eukaryotic pathway via the ER. Simultaneously, phosphatidylcholine and phosphatidylethanolamine, which are similar to DGTS in their zwitterionic properties, are almost completely degraded to release 18.1% cellular phosphorus, and to provide diacylglycerol moieties for a part of DGTS synthesis. This lipid remodeling system that substitutes DGTS for extrachloroplast phospholipids to lower the P-quota operates through the expression induction of the BTA1 gene. Investigation of this lipid remodeling system is necessary in a wide range of lower green plants for a comprehensive understanding of their phosphorus deficiency acclimation strategies.

Effect of a heat and moisture exchanger on temperature and humidity of inhaled gas in isoflurane-anesthetized dogs.

OBJECTIVE: To investigate the effects of a heat and moisture exchanger (HME) on the temperature and humidity of inhaled gas in isoflurane-anesthetized dogs. STUDY DESIGN: Prospective, interventional study. ANIMALS: A total of four experimental dogs and four client-owned dogs weighing 13.9 ± 7.4 kg (mean ± standard deviation). METHODS: The four experimental dogs were anesthetized on two occasions with and without an intact HME at least 1 week apart. The four client-owned dogs were anesthetized once only for a surgical procedure and assigned to the HME group or no-HME group in alternate order, resulting in six dogs for each group. All dogs were premedicated, anesthetized with propofol and intubated. The HME was connected to the endotracheal tube. Anesthesia was maintained with isoflurane. A digital thermo-hygrometer was placed between the endotracheal tube and HME. The temperature and relative humidity of the inhaled gas were measured every 5 minutes for 60 minutes and the absolute humidity was calculated at each time point. RESULTS: The temperature and absolute humidity of the inhaled gas was significantly higher at 5-60 minutes after intubation in the HME group than in the no-HME group. Absolute humidity was maintained above 29 mg H2O L-1 in the HME group. No significant time-dependent effects on temperature, relative humidity or absolute humidity of the inhaled gas were observed. CONCLUSIONS AND CLINICAL RELEVANCE: The temperature and absolute humidity of the inhaled gas were higher when an HME was used during isoflurane anesthesia in dogs. The use of an HME may reduce the risk of dehydration and dysfunction of the airway mucosal epithelium.

Regulatory carbon metabolism underlying seawater-based promotion of triacylglycerol accumulation in Chlorella kessleri.

Chlorella kessleri accumulates triacylglycerol usable for biodiesel-fuel production to >20% dry cell weight in three days when cultured in three-fold diluted seawater, which imposes the combinatory stress of hyperosmosis and nutrients limitation. The quantitative behavior of major C-compounds, and related-gene expression patterns were investigated in Chlorella cells stressed with hyperosmosis, nutrients limitation, or their combination, to elucidate the C-metabolism for economical seawater-based triacylglycerol accumulation. Combinatory-stress cells showed repressed protein synthesis with initially accumulated starch being degraded later, the C-metabolic flow thereby being diverted to fatty acid and subsequent triacylglycerol accumulation. This C-flow diversion was induced by cooperative actions of nutrients-limitation and hyperosmosis. Semi-quantitative PCR analysis implied positive rewiring of the diverted C-flow into triacylglycerol in combinatory-stress cells through upregulation of gene expression concerning fatty acid and triacylglycerol synthesis, and starch synthesis and degradation. The information of regulatory C-metabolism will help reinforce the seawater-based triacylglycerol accumulation ability in algae including Chlorella.

Effect of medetomidine on tear flow measured by Schirmer tear test I in normal pigs.

Medetomidine, an α2-adrenoceptor agonist, was reported to decrease tear flow in some species. However, there are no reports about the effect of medetomidine on tear flow in pigs. The purpose of this study was to elucidate it. The study was performed in 10 clinically normal female Landrace pigs aged 3 months. Tear flow was measured by the Schirmer tear test (STT) I before (baseline) and 15 and 30 min after intramuscular administration of 80 µg/kg medetomidine. Compared to the STT I value at baseline, the value decreased significantly at 30 min after administration in both the left and right eyes. In pigs treated with medetomidine, an artificial tear solution or ophthalmic gel should be applied to protect the ocular surface.