Characterization of a novel recombinant halophilic ß-glucosidase of Trichoderma harzianum derived from Hainan mangrove.

BACKGROUND: ß-glucosidase is an important biomass-degrading enzyme and plays a vital role in generating renewable biofuels through enzymatic saccharification. In this study, we analyzed the transcriptome of Trichoderma harzianum HTASA derived from Hainan mangrove and identified a new gene encoding ß-glucosidase Bgl3HB. And the biochemically characterization of ß-glucosidase activity was performed. RESULTS: Bgl3HB showed substantial catalytic activity in the pH range of 3.0-5.0 and at temperatures of 40 ℃-60 ℃. The enzyme was found quite stable at 50 ℃ with a loss of only 33.4% relative activity after 240 min of heat exposure. In addition, all tested metal ions were found to promote the enzyme activity. The ß-glucosidase activity of Bgl3HB was enhanced by 2.12-fold of its original activity in the presence of 5 M NaCl. Surprisingly, Bgl3HB also showed a remarkable ability to hydrolyze laminarin compared to other measured substrates. Enzyme efficiency was examined in the sugarcane bagasse saccharification processes, in which Bgl3HB with 5 M NaCl worked better supplementing Celluclast 1.5L than the commercial Novozyme 188 ascertained it as an admirably suited biocatalyst for the utilization of agricultural waste. In this work, this is the first report of a halophilic ß-glucosidase from Trichoderma harzianum, and represents the ß-glucosidase with the highest known NaCl activation concentration. And adding 5 M NaCl could enhance saccharification performance even better than commercial cellulase. CONCLUSIONS: These results show that Bgl3HB has great promise as a highly stable and highly efficient cellulase with important future applications in the industrial production of biofuels.

Inhibition of neuron-specific CREB dephosphorylation is involved in propofol and ketamine-induced neuroprotection against cerebral ischemic injuries of mice.

Propofol and ketamine may provide certain degree of neuroprotection, but the underlying mechanism remains unclear to date. The cAMP response element-binding protein (CREB) was proposed that its phosphorylation at Ser133 (P-CREB) constituted a convergence point involved in neuroprotection. The purpose of this study was to determine whether different dosages of propofol and ketamine could provide neuroprotection against permanent middle cerebral artery occlusion (MCAO)-induced ischemic injuries and the involvement of P-CREB. Eighty adult male BALB/c mice that underwent 6 h MCAO were randomly divided into eight groups: Sham-operation; MCAO + saline; MCAO + 25, 50, 100 mg/kg propofol; and MCAO + 25, 50, 100 mg/kg ketamine (intraperitoneal injection 30 min following MCAO). We found that 50, 100 (not 25) mg/kg propofol, and 25 (not 50 and 100) mg/kg ketamine could significantly reduce the infarct volume, edema ratio and neurological deficit (n = 10 per group) as well as inhibit the decrease of P-CREB level in peri-infarct region when compared with that of MCAO + saline group (n = 6 per group). In addition, the results of double-labeled immunofluorescent staining showed that P-CREB co-localized with neuron-specific marker, NeuN, in the peri-infarct region of 50 mg/kg propofol and 25 mg/kg ketamine treated 6 h MCAO mice (n = 4 per group). These results suggested that inhibition of neuron-specific P-CREB dephosphorylation in the peri-infarct region is involved in high dose propofol and low dose ketamine-induced neuroprotection of 6 h MCAO mice.

Development of a novel chronic intermittent hypoxia chamber.

OBJECTIVE: To develop a novel chronic intermittent hypoxia chamber for rat models. DESIGN: The intermittent hypoxia chamber included two animal cabins (28 × 20 × 15 cm) and a hypoxia chamber (80 × 80 × 60 cm) between them, as well as the actuating device. Pure nitrogen was fed into the hypoxia chamber continuously in order to keep the low O(2) concentration. Each animal cabin could move in and out of the hypoxia chamber with precise timing function. As a result, the animal cabins could be covered by the hypoxia chamber and got the same low O(2) concentration as in the hypoxia chamber and normal O(2) concentration as out of the hypoxia chamber. Twelve healthy, male Sprague-Dawley rats (200~250 g) were selected to test the effect of the intermittent hypoxia chamber. The O(2) concentration in the hypoxia chamber was 10 ± 0.5%, and the cycle time of intermittent hypoxia was 180 s (the hypoxia and normoxic time was 90 s, respectively). The hypoxia chamber ran 8 h per day. The arterial blood gas analysis (ABSA) of rats was conducted when the animal cabin was located inside and outside the hypoxia chamber. RESULTS: The chronic intermittent hypoxia chamber ran safely and reliably. The ABSA showed that the lowest PaO(2) was 35.75 ± 4.02 mmHg and the lowest SaO(2) was 68.62 ± 8.36% when the animal cabin was covered by the hypoxia chamber. CONCLUSIONS: The chronic intermittent hypoxia chamber designed by us was suitable to establish a chronic intermittent hypoxia model for rats.

Involvement of adenosine monophosphate-activated protein kinase in morphine-induced cardioprotection.

BACKGROUND: Adenosine monophosphate-activated protein kinase (AMPK) orchestrates the regulation of energy-generating and -consuming pathways, and protects the heart against ischemic injury and apoptosis. Recent progress shed light on various factors, including adiponectin, MIF, H11K, and metformin in the activation of AMPK. It is uncertain whether the activation of AMPK is contributed to cardioprotection of opioids. Here we show that morphine, an exogenous non-peptide opioid receptor agonist, can modulate the activation of the cardioprotective AMPK pathway during ischemia and exert anti-apoptotic effects through AMPK. METHODS: Isolated rat hearts were perfused on a constant pressure Langendorff system and subjected to 30 min of global ischemia followed by 60 min of reperfusion. The hearts received vehicles, morphine, a combination of morphine and compound C, a combination of morphine and STO609, a combination of morphine and BAPTA-AM at the onset of ischemia. Hemodynamics parameters, infarct size, release of intracellular creatine kinase, expression of AMPK, and terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling staining were analyzed. RESULTS: Morphine significantly increased phosphorylation level of Thr172 site on AMPK, left ventricular function, and reduced infarct size as a percentage of the area at risk (IS/AAR from 63% ± 7% to 40% ± 5%), release of intracellular creatine kinase (from 319 ± 46 to 156 ± 42IU/60 min/gdw), apoptosis ratio (from 16% ± 2% to 5% ± 1.4%) during reperfusion in comparison with the control group. A inhibitor of AMPK, compound C abrogated phosphorylation of AMPK induced by morphine, the improvement in myocardial function, and the reduction of IS/AAR (58% ± 6%), release of intracellular creatine kinase (270 ± 40IU/60 min/gdw), apoptosis ratio (13% ± 1.5%). A Ca(2+)/calmodulin-dependent protein kinase kinase inhibitor STO609 and a chelator of intracellular Ca(2+) stores BAPTA-AM also abolished the cardioprotection of morphine. CONCLUSIONS: Morphine can ameliorate myocardial contractile dysfunction and limit infarct size following ischemia and reperfusion by a mechanism involving activation of AMPK, and activate AMPK by Ca(2+)-CaMKKß-dependent phosphorylation.

C50 for propofol-remifentanil target-controlled infusion and bispectral index at loss of consciousness and response to painful stimulus in Chinese patients: a multicenter clinical trial.

BACKGROUND: In this study, we evaluated the predicted blood and effect-site C(50) for propofol and remifentanil target-controlled infusion and the Bispectral Index (BIS) values at loss of consciousness (LOC) and response to a standard noxious painful stimulus in Chinese patients. We hypothesized that these values would be different from previously published data on Caucasians. METHODS: Five medical centers enrolled 405 ASA physical status I and II unpremedicated Chinese patients (97 men, 308 women) aged 18-65 yr. Propofol was initially given to a predicted blood concentration of 1.2 microg/mL and thereafter increased by 0.3 microg/mL every 30 s until Observer's Assessment of Alertness and Sedation score was 1. The propofol was kept constant, and remifentanil was given to provide a predict blood concentration of 2.0 ng/mL, and then increased by 0.3 ng/mL every 30 s until loss of response to a tetanic stimulus. BIS (version 3.22, BIS Quattro sensor) was also recorded. RESULTS: The propofol effect-site C(50) at LOC was 2.2 (2.2-2.3) microg/mL. The remifentanil effect-site C(50) at loss of response to painful stimulus was 3.3 ng/mL. Fifty percent of patients lost consciousness at a BIS value of 58, and 95% had lost consciousness at BIS values <40. The BIS value at C(50) at loss of response to painful stimulus was 65.4, which was higher than that at LOS (P < 0.001). CONCLUSIONS: The predicted blood and effect-site concentrations of propofol and BIS values at LOC were lower than those in previously published studies of Caucasian populations.

Inhibition of PKCgamma membrane translocation mediated morphine preconditioning-induced neuroprotection against oxygen-glucose deprivation in the hippocampus slices of mice.

We previously reported that novel protein kinase C (nPKC) epsilon and N-methyl-d-aspartic acid (NMDA) receptors participated in morphine preconditioning (MP)-induced neuroprotection. In this study, we used Western blot analysis, 2,3,5-triphenyltetrazolium chloride (TTC) staining and lactate dehydrogenase (LDH) leakage assay to determine the involvement of conventional PKC isoforms (cPKC) in MP-induced neuroprotection against oxygen-glucose deprivation (OGD). Hippocampus slices (400-microm thickness) from healthy male BALB/c mice exposed to OGD for 5-45 min to mimic mild, moderate and severe ischemia in the presence of MP pretreatment. We found that OGD-induced damage in neuronal cell survival rate and LDH leakage could be improved by MP pretreatment (3 microM) within 20 min of OGD, which was abolished by concomitant incubation with non-selective opioid receptor antagonist naloxone (Nal, 50 microM). The results of Western blot analysis showed that only cPKCgamma membrane translocation, not alpha, betaI and betaII, increased under the condition of OGD 10 min and 2h reperfusion (OGD/2h), and this increment of cPKCgamma membrane translocation was inhibited by MP pretreatment. To further elucidate the role of cPKCgamma in MP-induced neuroprotection, we found that cPKCgamma membrane translocation inhibitor, Go6983 (6 nM) did not affect MP-induced neuroprotection while Go6983 alone exhibited a significant inhibition on OGD-induced increment in LDH leakage and decrease in cell survival rate. These phenomena were defined by the results that Go6983 could restore OGD-induced cPKCgamma membrane translocation, but had no further effect on MP-induced inhibition of cPKCgamma membrane translocation. These results demonstrated that MP can reduce OGD-induced neuronal injuries, and the down-regulation of cPKCgamma membrane translocation might be involved in the neuroprotection.

Effects of intravenous anesthetics on the phosphorylation of cAMP response element­binding protein in hippocampal slices of adult mice.

cAMP response­element binding protein (CREB) functions in hippocampal synaptic plasticity and memory formation. However, it remains unknown whether intravenous anesthetics modulate CREB. The present study aimed to examine the effects of intravenous anesthetics on CREB phosphorylation in the mouse hippocampus. CREB phosphorylation was examined in hippocampal slices with and without pharmacological or intravenous anesthetics via immunoblotting. In a dose­response experiment, the concentrations of intravenous anesthetics ranged from 10­9 to 10­4 mol/l for 1 h. For the time­response experiment, these slices were incubated with 5x10­6 mol/l of propofol for 0, 1, 2, 5, 7, 9, 12, 15, 30 and 60 min. In order to examine whether CREB phosphorylation could be recovered following washing out the propofol, the slices were incubated in plain artificial cerebrospinal fluid at different time durations following 5 min incubation with propofol. Propofol, etomidate, ketamine and midazolam inhibited CREB phosphorylation (P<0.05) in a time­ and dose­dependent manner. This inhibition was reversible following the removal of propofol, and was rescued by CREB phosphorylation (P<0.05). The decrease in CREB phosphorylation revealed additive effects with 100 µM of chelerythrine and 20 µM of PD­98059, and the etomidate­induced decrease in CREB phosphorylation was blocked by 1 mM of NMDA. However, 0.1 µM of phorbol 12­myristate 13­acetate, 50 µM of U 73122, 100 µM of carbachol and 10 µM of MK801 were ineffective in the anesthetic­induced decrease in CREB phosphorylation. Intravenous anesthetics markedly decreased CREB phosphorylation in the mouse hippocampus, which was most likely via the protein kinase C and mitogen activated protein kinase pathways. This suggests that CREB represents a target for anesthetic action in the brain.

Serine Alleviates Dextran Sulfate Sodium-Induced Colitis and Regulates the Gut Microbiota in Mice.

Serine alleviates inflammatory responses and is beneficial for gut health; however, whether it exerts any effects on ulcerative colitis or regulates intestinal microbiota remains unknown. We investigated the effects of serine supplementation on colonic morphology, inflammation, and microbiota composition in dextran sulfate sodium (DSS)-induced colitis model in mice. Acute colitis was induced through the oral intake of 3.5% DSS in water for 7 days. Mice with acute colitis were divided into two groups; The DSS and Ser-treated groups were rectally administrated with PBS or 1% (w/v) serine (40 mg/kg body weight) for 7 days. The results showed that serine decreased the disease activity index, as well as myeloperoxidase, eosinophil peroxidase, and proinflammatory cytokine concentrations in colonic tissue, while serine improved colonic morphology and inhibited cell apoptosis in colitis mice. In addition, 16S rRNA phylogenetic sequencing revealed a shift in bacterial community composition, and changes in microbiota functional profiles following serine supplementation, although no significant difference in α-diversity analysis was observed. The effects of serine supplementation helped on the recovery of major perturbations to macrobiotic functions, such as amino acids metabolism; tissue replication and repair; and cell growth and death. Serine might have great potential for the renewal of colonic tissue in DSS-induced colitis.

Effects of cathelicidin-derived peptide from reptiles on lipopolysaccharide-induced intestinal inflammation in weaned piglets.

Cathelicidins are the largest family of antimicrobial peptides. C-BF, which is short for Cathelicidin-Bungarus Fasciatus, was isolated from snake venom. C-BF was found to be the most potential substitutes for antibiotics. In this study, we analyzed the effects of cathelicidin-derived peptide C-BF, on lipopolysaccharide (LPS)-induced intestinal damage in weaned piglets, to evaluate the therapeutic effect of C-BF on infectious disease of piglets. Twenty-four piglets were randomly assigned into four groups: control, C-BF, LPS, and C-BF+LPS. The LPS and C-BF+LPS groups were intraperitoneally injected with LPS at fixed timepoints, while the control and C-BF groups were injected with equal volumes of saline. The C-BF and C-BF+LPS groups were then intraperitoneally injected with antimicrobial peptide C-BF, while the control and LPS groups were injected with equal volumes of saline. All piglets were observed for 15days and then sacrificed for analysis. The results showed that C-BF significantly improved the growth performance of weaned piglets compared with LPS-treated animals (P<0.05), and that C-BF could ameliorate the structural and developmental damage to the small intestine caused by LPS treatment. Further, the level of apoptosis in the LPS group was significantly higher than in the other three groups (P<0.05), as was the invasion of inflammatory cells into the intestinal mucosa of the jejunum (P<0.05), leading to increased secretion of pro-inflammatory cytokines. In conclusion, the study indicates that C-BF treatment may be a potential therapy for LPS/pathogen-induced intestinal injury in piglets.

The neurotoxicity of intrathecal lidocaine is enhanced in postpartum compared to virgin rats.

During the perinatal period, the pharmacokinetics and pharmacodynamics of drugs may be altered. Data about the neurotoxicity of intrathecal local anesthetics in the peripartum period are lacking. So we hypothesized that the neurotoxicity of intrathecal lidocaine during perinatal period may be changed. Therefore, we designed the present study to determine whether the neurotoxicity of intrathecal lidocaine in postpartum rats would be different from that in nonpregnant, virgin rats. Postpartum and nonpregnant rats randomly received an intrathecal infusion of lidocaine 50 mg/mL in saline, lidocaine 20 mg/mL in saline, or saline for 1 h at a rate of 1 µL/min. Four days after drug infusion, the rats were assessed for persistent impairment of sensory and motor function (MF) using the tail-flick (TF) test, paw pressure test, and MF score. Spinal cords and nerve roots were obtained for light and electron microscopic examinations, and the injury scores were compared between groups. The TF latencies and the mean nerve injury scores of the postpartum group were significantly higher than those of nonpregnant group. Lidocaine induced a dose-dependent impairment in TF latencies and nerve injury scores. There was no significant interaction between postpartum and the drug. Our results suggest that the neurotoxicity of intrathecal lidocaine is enhanced in rats during the early postpartum period compared with nonpregnant, virgin rats.

Shikani™ Seeing Optical Stylet-aided tracheal intubation in patients with a large epiglottic cyst.

Large epiglottic cysts can block the glottis, leading to serious consequences. This condition presents a challenge in terms of airway management for anesthesiologists during induction of anesthesia. We report the use of a Shikani™ Seeing Optical Stylet combined with a Macintosh laryngoscope to aid tracheal intubation in seven patients with large epiglottic cysts. Use of this technique can avoid cyst rupture and allow smooth, safe intubation.

An improved method for protecting and fixing the lumbar catheters placed in the spinal subarachnoid space of rats.

The chronic intrathecal catheterization of the subarachnoid space in the rat is a very useful model in the research of neuroscience, anesthesiology, neurotoxicity, and etc. To avoid high postoperative mortality and neurological impairment, the catheterization from the lumbar interspace has been widely used in recent years. But one of the most discouraging disadvantages is that the external portion of the chronic indwelling catheters is easily damaged by rats. Besides, the short length of catheter left in the subarachnoid space in addition to its slimness makes it difficult for proper fixation. To improve the abovementioned situations, we designed a protector to protect the external portion of the catheters and developed a simple method for better fixation. Results suggest that this is an excellent method for protecting and fixing the lumbar catheters placed in the subarachnoid space of rats, and this method did not affect the sensory and motor function of the rat. The general conditions of the rats were unswayed.

Propofol and ketamine-induced anesthetic depth-dependent decrease of CaMKII phosphorylation levels in rat hippocampus and cortex.

Ca/calmodulin-dependent protein kinase II (CaMKII) activation through autophosphorylation at threonine 286 was involved in the modulation of neuronal excitability and neurotransmission. Both propofol and ketamine may affect the intracellular Ca levels through N-methyl-D-aspartate receptors or voltage-dependent Ca channels, but they have different mechanisms in general anesthesia. The purpose of this study was to investigate the effects of propofol and ketamine on CaMKII total protein and phosphorylation (p-CaMKII) levels in the brain of rats. We found that both propofol and ketamine could induce a decrease of p-CaMKII, not CaMKII total protein, in an anesthetic depth-dependent manner, whereas only ketamine caused a dose (50, 100, and 150 mg/kg)-dependent depression of p-CaMKII in hippocampus and frontal cortex of rats after intraperitoneal injections for 30 minutes. The significant depressions of p-CaMKII started at 5 minutes both in hippocampus and frontal cortex of rats after 100 mg/kg propofol treatment, whereas 100 mg/kg ketamine-induced significant depression of p-CaMKII initiated at 30 minutes in hippocampus and 5 minutes (no reduction observed at 15 min) in frontal cortex of rats. The maximum reduction of p-CaMKII with both drugs was at 60 minutes, and then restored to control level at 240 minutes. In addition, we confirmed the depression of p-CaMKII in hippocampus and frontal cortex of rats after 100 mg/kg of propofol or ketamine treatment for 60 minutes by using immunostaining. These results suggested that decreased p-CaMKII levels correlate with anesthetic depths achieved by propofol and ketamine, which may be related to the effects of propofol and ketamine on central nervous system function and their clinical effect.

Morphine postconditioning protects against reperfusion injury in the isolated rat hearts.

BACKGROUND: Postconditioning is a novel strategy of attaining cardioprotection. Previous studies have suggested morphine mimics the effects of ischemic preconditioning. Whether it is also capable of producing postconditioning or not is still unclear. The purpose of this study was to determine (1) whether morphine postconditioning (MPostcond) would protect the heart against reperfusion injury and the subtype(s) of opioid receptors (OR) involved, (2) whether combining MPostcond with morphine preconditioning (MPC) would afford additive cardioprotection, and (3) to evaluate the role mitochondrial adenosine triphosphate-sensitive potassium (mito-K atp) channel played in MPostcond. MATERIALS AND METHODS: Isolated perfused rat hearts were subjected to 45 min of ischemia followed by 1 h of reperfusion. First, three morphine concentrations (0.3, 3.0 and 30 microM) were used to study the protective effect of MPostcond. Second, the effect of blockade of OR subtypes by three antagonists (nonselective OR antagonist naloxone, kappa-OR antagonist nor-binaltorphimine, and delta-OR antagonist naltrindole) on MPostcond was investigated. Third, the protective effects of MPC, MPostcond and the combining MPC with MPostcond on reperfusion injury were compared. Last, the effect of blockade of mito-K atp by 5-hydroxydecanoate on MPostcond was studied. MPostcond was induced by a 10-min perfusion of morphine in Krebs-Ringer's solution performed at the onset of reperfusion, and MPC was produced by a 20-min perfusion of morphine 10 min before ischemia. Infarct size (IS/AAR, as a percentage of the area at risk) was determined by 2,3,5-triphenyltetrazolium staining. RESULTS: IS/AAR was significantly reduced after MPostcond from 58% +/- 8% (control) to 37% +/- 6% (morphine 3.0 microM, P < 0.01). This effect was abolished by coadministering naloxone (58% +/- 7%), nor-binaltorphimine (52% +/- 5%), but not naltrindole (34% +/- 5%). MPC and MPostcond had similar extent of protective effect on IS/AAR, and combining MPC with MPostcond did not afford further cardiprotection. 5-Hydroxydecanoate also abolished the cardioprotection of MPostcond. Unexpectedly, all three OR antagonists and 5-hydroxydecanoate themselves also afforded some extent of cardioprotection. CONCLUSIONS: MPost confers cardioprotection via activating kappa-OR but not delta-OR and opening mito-K atp channels. MPost and MPC have no additive protection. kappa-OR and mito-K atp channel may play a dual role in protecting ischemia-reperfusion injury.