Physiological mechanism underlying the effect of high temperature during anthesis on spikelet-opening of photo-thermo-sensitive genic male sterile rice lines.

Decrease in the grain yield resulted from a low percentage of opened spikelets under high temperature (HT) during anthesis is a serious problem in the seed production of photo-thermo-sensitive genic male sterile (PTGMS) rice (Oryza sativa L.) lines, and the mechanism is little understood. Elucidating the physiological mechanism underlying the effect of HT during anthesis on spikelet-opening of PTGMS lines would have great significance in exploring the effective way to mitigate the adverse effect of HT. In this study, two PTGMS lines and one restorer line of rice were used and were subjected to normal temperature (NT) and HT treatments. The results showed that, compared with NT, HT significantly decreased the percentage of opened spikelets, fertilization percentage and seed-setting by significantly increasing the percentage of wrapped spikelets and reducing the spikelet-opening angle, length of spikelet-opening time. The HT significantly decreased the contents of soluble sugars, jasmonic acid (JA) and methyl jasmonate (MeJA) in the lodicules before and at glume-opening, which were significantly correlated with and accounts for the low percentage of opened spikelets under HT for rice, especially for the PTGMS lines.

Ketamine and propofol in combination induce neuroapoptosis and down-regulate the expression of N-methyl-D-aspartate glutamate receptor NR2B subunit in rat forebrain culture.

BACKGROUND AND OBJECTIVE: Ketamine has always been used in combination with propofol in paediatric patients. Ketamine interacts with N-methyl-D-aspartate glutamate receptor to exert its biologic actions. The NMDA receptor NR2B subunit is expressed at nearly adult level during forebrain development in the cortex and considered as the major type of functional NMDA receptor in the central nervous system. This study aimed to investigate whether ketamine or ketamine in combination with propofol induces apoptosis and regulates the expression level of NMDA receptor NR2B subunit in rat forebrain culture. METHODS: Rat primary forebrain cultures were exposed to different concentrations of ketamine (1 microM, 10 microM, 20 microM) or 20 microM ketamine plus 5 microM propofol on the 6th day for 12 h. Cell viability was examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Caspase-3 activity was measured and apoptotic morphology was examined by Hoechst dye staining. The expression of NMDA receptor NR2B subunit at mRNA and protein level was determined by qPCR and Western blot, respectively. RESULTS: Ketamine (10 microM and 20 microM) or 20 microM ketamine plus 5 microM propofol resulted in a significant decrease in cell viability, and a significant increase in caspase-3 activity and apoptosis of primary rat forebrain culture. The expression of NMDA receptor NR2B subunit at both mRNA and protein levels were down-regulated by administration of ketamine (1 microM, 10 microM and 20 microM) and 20 microM ketamine plus 5 microM propofol. CONCLUSION: Ketamine (10 microM or 20 microM) alone or in combination with propofol (20 microM ketamine plus 5 microM propofol) induces neuroapoptosis and down-regulates of NMDA receptor NR2B subunit in rat forebrain culture.

A hepatopancreas-specific C-type lectin from the Chinese shrimp Fenneropenaeus chinensis exhibits antimicrobial activity.

Lectins play important roles in animal innate immune responses by serving as pattern recognition receptors, opsonins, or effector molecules. Here, we report a novel hepatopancreas-specific C-type lectin, designated Fc-hsL, from the hepatopancreas of the Chinese shrimp, Fenneropenaeus chinensis. The cDNA of Fc-hsL is 571 bp long with a 480 bp open reading frame that encodes a 159-residue protein. Fc-hsL contains a signal peptide and a single C-type lectin-like domain (CTLD) or carbohydrate recognition domain (CRD). It has an EPN(Glu-Pro-Asn) motif with a predicted ligand-binding site specific for mannose. Fc-hsL was constitutively expressed in the hepatopancreas of normal shrimp, and its expression was up-regulated following challenge of shrimp with bacteria or virus. Fc-hsL was not detected in other tissues but was induced in the stomach of immune-challenged shrimp. Fc-hsL protein was detected in both hemolymph and the hepatopancreas of bacteria- and virus-challenged shrimp. Recombinant mature Fc-hsL has no hemagglutinating activity, but calcium-dependent agglutinating activity against some Gram-positive and Gram-negative bacteria was detected. The rFc-hsL also has binding activity to some Gram-positive and Gram-negative bacteria and high antimicrobial activity against some bacteria and fungi. These in vitro functions of recombinant Fc-hsL were calcium-independent. Fc-hsL may act as a pattern recognition receptor in antibacterial defense and as an effector in innate immunity of Chinese shrimp.