[Effects of melatonin on photosynthetic properties and osmoregulatory substance contents of cucumber seedlings under salt-alkali stress]. / è¤ªé»‘ç´ å¯¹ç›ç¢±å¤åˆèƒè¿«ä¸‹é»„ç“œå¹¼è‹—å ‰åˆç‰¹æ€§å’Œæ¸—é€è°ƒèŠ‚ç‰©è´¨å«é‡çš„å½±å“.

To determine the mitigating effects of exogenous melatonin on salt-alkali stress in cucumber, we mea-sured photosynthetic characteristics and osmoregulatory substance content of cucumber leaves under salt-alkali stress, using 'Xinchun 4' cucumber as the test material and a salt-alkali complex (NaCl:Na2SO4:Na2CO3:NaHCO3 = 1:9:1:9) to simulate stress. The results showed that compared with the normal seedlings, the exogenous application of 10 µmol·L-1 melatonin significantly increased the contents of chlorophyll, soluble sugar, and soluble protein, as well as net photosynthetic rate, stomatal conductance, transpiration rate, photosystem Ⅱ maximum photochemical efficiency, actual photochemical efficiency, apparent photosynthetic electron transfer rate, and photochemical burst coefficient of cucumber seedlings under 40 mmol·L-1 salt-alkali stress, but decreased intercellular CO2 concentration, non-photochemical burst coefficient, and sucrose, fructose, starch, and proline contents by 11.1%, 13.8%, 12.7%, 27.5%, 1.3% and 32.8%, respectively. Moreover, the activities of key enzymes for carbon assimilation (including ribulose-1,5-bisphosphate carboxylase/oxygenase and fructose-1,6-bisphosphate esterase) were significantly increased, whereas the mRNA expression levels of Rubisco subunits (CsrbcS and CsrbcL), CsFBA, CsRCA, CsFBPase and CsTK were downregulated. In conclusion, exogenous melatonin could increase the contents of chlorophyll and osmoregulatory substance, photosynthetic chemical efficiency, and key carbon assimilation enzyme activities of cucumber seedlings under salt-alkali stress, thereby enhance photosynthetic capacity and reduce the stress-induced plant damage. The results would provide theoretical basis for anti-saline plant cultivation.

Mean arterial pressure is associated with the neurological function in patients who survived after cardiopulmonary resuscitation: A retrospective cohort study.

BACKGROUND: About 18% to 40% of the survivors have moderate to severe neurological dysfunction. At present, studies on mean arterial pressure (MAP) and neurological function of patients survived after cardiopulmonary resuscitation (CPR) are limited and conflicted. HYPOTHESIS: The higher the MAP of the patient who survived after CPR, the better the neurological function. METHOD: A retrospective cohort study was conducted to detect the relationship between MAP and the neurological function of patients who survived after CPR by univariate analysis, multivariate regression analysis, and subgroup analysis. RESULTS: From January 2007 to December 2015, a total of 290 cases met the inclusion criteria and were enrolled in this study. The univariate analysis showed that MAP was associated with the neurological function of patients who survived after CPR; its OR value was 1.03 (1.01, 1.04). The multi-factor regression analysis also showed that MAP was associated with the neurological function of patients survived after CPR in the four models, the adjusted OR value of the four models were 1.021 (1.008, 1.035); 1.028 (1.013, 1.043); 1.027 (1.012, 1.043); and 1.029 (1.014, 1.044), respectively. The subgroups analyses showed that when 65 mm Hg ≤ MAP<100 mm Hg and when patients with targeted temperature management or without extracorporeal membrane oxygenation, with the increase of MAP, the better neurological function of patients survived after CPR. CONCLUSION: This study found that the higher MAP, the better the neurological function of patients who survived after CPR. At the same time, the maintenance of MAP at 65 to 100 mm Hg would improve the neurological function of patients who survived after CPR.

Irisin protects against neuronal injury induced by oxygen-glucose deprivation in part depends on the inhibition of ROS-NLRP3 inflammatory signaling pathway.

Recent studies found that irisin, a newly discovered skeletal muscle-derived myokine during exercise, is also synthesized in various tissues of different species and protects against neuronal injury in cerebral ischemia. The NOD-like receptor pyrin 3 (NLRP3) inflammasome play an important role in detecting cellular damage and mediating inflammatory responses to aseptic tissue injury during ischemic stroke. However, it is unclear whether irisin is involved in the regulation of NLRP3 inflammasome activation during ischemic stroke. In the present study, PC12 neuronal cells were exposed to oxygen-glucose deprivation (OGD), exogenous irisin (12.5, 25, 50nmol/L) or NLRP3 inhibitor glyburide (50, 100, 200µmol/L) were used as an intervention reagent, NLRP3 was over-expressed or suppressed by transfection with a NLRP3 expressing vector or NLRP3-specifc siRNA, respectively. Our data showed that both irisin and its precursor protein fibronectin type III domain containing 5 (FNDC5) expression were significantly down-regulated (p<0.05); but oxidative stress and ROS-NLRP3 inflammasome signaling were activated by OGD (p<0.05); treatment with irisin or inhibition of NLRP3 reversed OGD-induced oxidative stress and inflammation (p<0.05). However, these irisin-mediated effects were blunted by over-expression NLRP3 (p<0.05). Taken together, our results firstly revealed that irisin mitigated OGD-induced neuronal injury in part via inhibiting ROS-NLRP3 inflammatory signaling pathway, suggesting a likely mechanism for irisin-induced therapeutic effect in ischemic stroke.

Molecular cloning and characterization of α-amylase/subtilisin inhibitor from rhizome of Ligusticum chuanxiong.

OBJECTIVES: To clone and characterize a novel bi-functional α-amylase/subtilisin inhibitor (LASI) from the rhizome of Ligusticum chuanxiong, a traditional Chinese medicine. RESULTS: The LASI showed strong homology with members of the Kunitz trypsin inhibitor family. Its putative amino acid sequence has a 40 % identity with that of the α-amylase/subtilisin inhibitor from rice. LASI gene without signal peptide was expressed in E. coli Rosetta. After purification, the recombinant LASI protein was inhibitory against not only α-amylase from porcine pancreas, Helicoverpa armigera, Spodoptera litura and Plutella xylostella, but also subtilisin A, but not against trypsin or chymotrypsin. In addition, the expression level of LASI in rhizome was higher than that in leaf and LASI expression was enhanced by salt, chilling and drought treatment. CONCLUSIONS: This is the first member of the Kunitz-protease inhibitor family identified in traditional Chinese medicine and it might be involved in the plant defense responses against lepidopterous pests, microorganisms and abiotic stresses.

[Effects of exogenous salicylic acid and brassinolide on photosynthesis of cucumber seedlings under low temperature stress.] / æ°´æ¨é ¸å’Œæ²¹èœç´ å† é ¯å¯¹ä½Žæ¸©èƒè¿«ä¸‹é»„ç“œå¹¼è‹—å ‰åˆä½œç”¨çš„å½±å“.

An experiment was conducted to investigate the mechanism of the regulation of salicylic acid (SA) and 2,4-epibrassionolide (EBR) on photosynthesis in cucumber (Cucumis sativa) seedlings under low temperature stress. Taking cucumber cultivar 'Youbo1-5' as material, the seedlings were pre-treated with 1 mmol·L-1 SA or 0.1 µmol·L-1EBR (sprayed once a day), and then were exposed to chilling temperature (10 ℃/5 ℃, PFD 80 µmol·m-2·s-1) after being pre-treated 2 days. The results showed that the growth and net photosynthetic rate (Pn) of cucumber seedlings were decreased under low temperature stress. However, the Pn, maximal photochemical efficiency of PS2 (Fv/Fm), actual photochemical efficiency of PS2 (ΦPS2) and photochemical quenching coefficient (qP) were significantly improved in SA- and EBR-pretreated seedlings, and the increase range of non-photochemical quenching coefficient (NPQ) was decreased. Moreover, the activities of ribulose 1,5-biphosphate carboxylase/oxygenase (Rubisco), sedoheptulose-1,7-bisphosphatase (SBPase), fructose-1,6-bisphosphate aldolase (FBA) and transketolase (TK) were signi-ficantly increased. These findings suggested that SA and EBR improved photosynthesis of cucumber seedlings by promoting the activities of key enzymes and increased low temperature tolerance.

Molecular cloning and characterization of caffeic acid 3-O-methyltransferase from the rhizome of Ligusticum chuanxiong.

OBJECTIVES: To clone and characterize caffeic acid 3-O-methyltransferase (LcCOMT) from the rhizome of Ligusticum chuanxiong, a traditional medicinal herb having a high content of ferulic acid. RESULTS: LcCOMT encoded an ORF of 362 amino acids with a calculated MW of 39,935 Da and pI of 5.94. Polygenetic tree indicated that LcCOMT was attributed to a new member of COMTs in plants. The recombinant LcCOMT was expressed in E. coli. HPLC and (1)H NMR analyses of purified LcCOMT protein confirmed that it could catalyze caffeic acid to produce ferulic acid in vitro. The further site-mutagenesis proved that His268 was one key catalytic residue. In addition, the substantial changing expression level of LcCOMT under chilling treatment suggested that LcCOMT might play important role in the accumulation of ferulic acid under chilling treatment. CONCLUSIONS: This is the first report of the isolation and characterization of a COMT clone from traditional medicine containing high contents of pharmaceutical ferulic acid.

[Situation of distribution and utilization of crop straw resources in seven western provinces, China].

Based on agricultural statistical and investigating data on farmers, amount, distribution density and amount per capita of crop straw resources of seven western provinces of China were estimated, the trends of amount dynamics from 1997 to 2011 and distribution and utilization of crop straw resources were analyzed, and the constraints of comprehensive utilizing straw resources and possible ways to improve straw utilization were discussed. Results showed that theoretical amount of crop straw resources in seven western provinces was 8.82 x 10(7) t in 2009, in which straw of cereals accounted for 63.1% of the total, and straw nutrients returned back to fields was 1.20 x 10(6) t, accounting for 50.5% of the total. The distribution density of straw resources of the seven western provinces was less than the national mean, while the amount per capita of straw resources was higher. According to the survey, the straw was mainly used as fuel, feed, industrial materials, matrix and returned field directly, accounting for 33.8%, 29.3%, 5.2%, 1.8% and 13.5% of the total amount, respectively. In addition, the amounts of straw burned and abandoned were 11.1% and 5.3% of the total, respectively.

[Effects of different nitrogen forms and their ratios on broccoli yield, quality, and nutrient absorption].

A field experiment was conducted to study the effects of different nitrogen forms ((NH2)2CO-N, NO(3-)-N, NH(4+)-N, and NO(3-)-NH4+) and their ratios on the yield formation, quality, and nutrient (N, P, and K) absorption of broccoli (Brassica oleracea). Fertilization with NO(3-)-N increased the accumulation of nitrate and soluble sugars in ball flower. When the NO(3-)-N: NH(4+)-N ratio was ranged from 3:7 to 5:5 and from 5:5 to 7:3, respectively, the accumulation of nitrate in the ball flower was reduced, while the soluble sugars content was promoted. Fertilization with (NH2)2CO-N and NH(4+)-N was conducive to the improvement of Vc content in the ball flower. N fertilization increased the accumulation of N, P, and K in plants, with the highest contents of N, P, and K observed at rosette stage. Throughout the entire growth period, NH(4+)-N fertilization improved the plant N content, whereas NO(3-)-N fertilization improved the plant K content. At different growth stages, the effects of different N sources on plant P content varied. As compared with applying single N forms, the NO(3-)-N:NH(4+)-N ratio ranged from 3:7 to 5:5 could improve the yield significantly. It was suggested that a combined application of NO(3-)-N and NH(4+)-N with an appropriate ratio could improve the productivity, quality, and economic return of broccoli.

Nitric oxide and hydrogen peroxide alleviate drought stress in marigold explants and promote its adventitious root development.

Drought stress is one of the most important environmental factors that regulates plant growth and development. In this study, we examined the effects of nitric oxide (NO) and hydrogen peroxide (H(2)O(2)) on adventitious rooting in marigold (Tagetes erecta L.) under drought stress. The results showed that the promoting effect of NO or H(2)O(2) on rooting under drought stress was dose-dependent, with a maximal biological response at 10 µM NO donor sodium nitroprusside (SNP) or 600 µM H(2)O(2). Results also indicated that endogenous NO and H(2)O(2) may play crucial roles in rooting under drought conditions, and H(2)O(2) may be involved in rooting promoted by NO under drought stress. NO or H(2)O(2) treatment attenuated the destruction of mesophyll cells ultrastructure by drought stress. Similarly, NO or H(2)O(2) increased leaf chlorophyll content, chlorophyll fluorescence parameters (Fv/Fm, ΦPS II and qP), and hypocotyls soluble carbohydrate and protein content, while decreasing starch content. Results suggest that the protection of mesophyll cells ultrastructure by NO or H(2)O(2) under drought conditions improves the photosynthetic performance of leaves and alleviates the negative effects of drought on carbohydrate and nitrogen accumulation in explants, thereby adventitious rooting being promoted.

[A biomechanical study of anterior screw fixation for type II odontoid fracture with anteroinferior-posterosuperior fracture line].

OBJECTIVE: To investigate the biomechanical effect of anterior screw fixation on the type II fractured odontoid process. METHODS: Twenty fresh human C1-C2 vertebrae specimens were harvested and randomly divided into three groups. The angle of type II fracture line was 0 degree in group I (n=6), 17 degrees in group II (n=8) and 25 degrees in group III (n=6). The fractures were treated by anterior screw fixation. Insertion torque,maximal axial pullout force and stiffness of the bone-screw were tested. RESULTS: There was no significant difference of screw insertion torque and the pull-out strength between each group. The displacement of the odontoid fragment had an association to the angle of the fracture line,the displacement of the small angle was significantly higher than that of the large one (P < 0.5). No significant difference of structure stiffness of the bone-screw was found between each group. CONCLUSION: Anterior screw fixation is feasible for type II odontoid fracture with certain fracture line extends from anteroinferior to posterosuperior.