Anaerobic Ammonium Oxidation Bacteria in a Freshwater Recirculating Pond Aquaculture System.

Anaerobic ammonium oxidation (anammox) is a key biochemical process to reduce nitrogen pollution in aquaculture, especially in water recirculating pond aquaculture system (RPAS). We used 16S RNA and quantified PCR to study the distribution and environmental impacts of anammox bacteria in RPAS. The results show that the anammox bacterial community distributions and diversities that are apparently unit-specific and seasonal have significant (p < 0.05) difference variation in the RPAS. Most of the anaerobic ammonium oxidation bacteria sequences (77.72%) retrieved from the RPAS belong to the Brocadia cluster. The abundance of anammox bacterial in the RPAS ranged from 3.33 × 101 to 41.84 × 101 copies per ng of DNA. The environmental parameter of temperature and nitrogen composition in water could have impacted the anammox bacterial abundance. This study provides more information on our understanding of the anammox bacteria in the RPAS, and provides an important basis for RPAS improvement and regulation.

Mutations in C1orf194, encoding a calcium regulator, cause dominant Charcot-Marie-Tooth disease.

Charcot-Marie-Tooth disease is a hereditary motor and sensory neuropathy exhibiting great clinical and genetic heterogeneity. Here, the identification of two heterozygous missense mutations in the C1orf194 gene at 1p21.2-p13.2 with Charcot-Marie-Tooth disease are reported. Specifically, the p.I122N mutation was the cause of an intermediate form of Charcot-Marie-Tooth disease, and the p.K28I missense mutation predominately led to the demyelinating form. Functional studies demonstrated that the p.K28I variant significantly reduced expression of the protein, but the p.I122N variant increased. In addition, the p.I122N mutant protein exhibited the aggregation in neuroblastoma cell lines and the patient's peroneal nerve. Either gain-of-function or partial loss-of-function mutations to C1ORF194 can specify different causal mechanisms responsible for Charcot-Marie-Tooth disease with a wide range of clinical severity. Moreover, a knock-in mouse model confirmed that the C1orf194 missense mutation p.I121N led to impairments in motor and neuromuscular functions, and aberrant myelination and axonal phenotypes. The loss of normal C1ORF194 protein altered intracellular Ca2+ homeostasis and upregulated Ca2+ handling regulatory proteins. These findings describe a novel protein with vital functions in peripheral nervous systems and broaden the causes of Charcot-Marie-Tooth disease, which open new avenues for the diagnosis and treatment of related neuropathies.

Targeting cancer cell metabolism with mitochondria-immobilized phosphorescent cyclometalated iridium(iii) complexes.

Cancer cell metabolism is reprogrammed to sustain the high metabolic demands of cell proliferation. Recently, emerging studies have shown that mitochondrial metabolism is a potential target for cancer therapy. Herein, four mitochondria-targeted phosphorescent cyclometalated iridium(iii) complexes have been designed and synthesized. Complexes 2 and 4, containing reactive chloromethyl groups for mitochondrial fixation, show much higher cytotoxicity than complexes 1 and 3 without mitochondria-immobilization properties against the cancer cells screened. Further studies show that complexes 2 and 4 induce caspase-dependent apoptosis through mitochondrial damage, cellular ATP depletion, mitochondrial respiration inhibition and reactive oxygen species (ROS) elevation. The phosphorescence of complexes 2 and 4 can be utilized to monitor the perinuclear clustering of mitochondria in real time, which provides a reliable and convenient method for in situ monitoring of the therapeutic effect and gives hints for the investigation of anticancer mechanisms. Genome-wide transcriptional analysis shows that complex 2 exerts its anticancer activity through metabolism repression and multiple cell death signalling pathways. Our work provides a strategy for the construction of highly effective anticancer agents targeting mitochondrial metabolism through rational modification of phosphorescent iridium complexes.

[Community Characteristics of ANAMMOX Bacteria in Subsurface Flow Constructed Wetland (SSFCW) for Processing of Aquaculture Waster Water].

Anaerobic ammonium oxidation (ANAMMOX) is one of the important functions in waste water treatment by subsurface flow constructed wetland (SSFCW), however, there are few studies on ANAMMOX in SSFCW environment at present. The community characteristics of ANAMMOX in the SSFCW of processing aquaculture waste water were explored in this study. In order to analyze the structure, diversity and abundance of ANAMMOX bacteria, several 16S rRNA clone libraries were constructed and real-time PCR targeting specific 16S rRNA genes together with diversity analysis was adopted. The obtained results showed that the SSFCW identified a total of three unknown clusters and two known clusters including Candidatus brocadia and Candidatus kuenenia. The dominant cluster was Candidatus brocadia. The highest diversity levels of ANAMMOX bacteria occurred in autumn (H', 1.21), while the lowest in spring (H', 0.64). The abundance of ANAMMOX bacteria in SSFCW environment ranged from 8.0 x 10(4) to 9.4 x 10(6) copies x g(-1) of fresh weight and the copy number of total bacterial 16S rRNA genes ranged from 7.3 x 10(9) to 9.1 x 10(10) copies x g(-1) of fresh weight during culture cycle. There were significant differences in the ANAMMOX bacteria abundances of different stratum and seasons in SSFCW environment, but the differences in total bacterial abundances were not obvious. In addition, the differences in ANAMMOX bacteria abundances in different stratum and seasons in SSFCW environment were irregular in different culture cycle. According to the distribution characteristics of ANAMMOX bacteria in the wetland, the denitrification effect of SSFCW could be improved by changing the supplying manners of aquaculture wastewater and adjusting the structure of wetland. The research results will provide reference for further optimizing the SSFCW and improving the efficiency of purification.

Mitochondrial Membrane Potential-dependent Endoplasmic Reticulum Fragmentation is an Important Step in Neuritic Degeneration.

BACKGROUND: Neuritic degeneration is an important early pathological step in neurodegeneration. AIM: The purpose of this study was to explore the mechanisms connecting neuritic degeneration to the functional and morphological remodeling of endoplasmic reticulum (ER) and mitochondria. METHODS: Here, we set up neuritic degeneration models by neurite cutting-induced neural degeneration in human-induced pluripotent stem cell-derived neurons. RESULTS: We found that neuritic ER becomes fragmented and forms complexes with mitochondria, which induces IP3R-dependent mitochondrial Ca(2+) elevation and dysfunction during neuritic degeneration. Furthermore, mitochondrial membrane potential is required for ER fragmentation and mitochondrial Ca(2+) elevation during neuritic degeneration. Mechanically, tightening of the ER-mitochondria associations by expression of a short "synthetic linker" and ER Ca(2+) releasing together could promote mitochondrial Ca(2+) elevation, dysfunction, and reactive oxygen species generation. CONCLUSION: Our study reveals a dynamic remodeling of the ER-mitochondria interface underlying neuritic degeneration.

Amide groups switch selectivity: C-H trifluoromethylation of α,ß-unsaturated amides and subsequent asymmetric transformation.

The first direct C-H ß-trifluoromethylation of unsubstituted or α-alkyl-substituted α,ß-unsaturated carbonyl compounds under metal-free conditions was realized with excellent regio- and stereoselectivity as well as a very broad substrate scope. Both olefinic and allylic trifluoromethylation products are accessible with high selectivities by altering the substrate substitutions. The resultant olefinic products, namely (E)-ß-trifluoromethyl (CF3) α,ß-unsaturated hydroxamic acid derivatives, served as acceptors in organocatalytic asymmetric Michael addition reactions to give hydroxamic acid derivatives bearing a chiral CF3-substituted stereocenter with high enantioselectivities.

Preparation of an osteochondral composite with mesenchymal stem cells as the single-cell source in a double-chamber bioreactor.

A double-chamber bioreactor has been developed to generate a tissue-engineered osteochondral composite (TEOC). However, a TEOC generally requires two types of cells (i.e. chondrogenic and osteogenic cells). Therefore, the capacity of mesenchymal stem cells (MSCs) as a single-cell source to work within a double-chamber bioreactor and biphasic scaffolds for generating TEOC was investigated. Compared with static culture, the double-chamber bioreactor not only can promote faster cellular proliferation, indicated by the PicoGreen dsDNA assay, SEM and confocal imaging, but also can trigger efficient chondrogenic and osteogenic differentiation of MSCs in biphasic scaffolds simultaneously, evidenced by gene expression. Thus MSCs are promising as the ideal single-cell source and the double-chamber bioreactor is an advanced culture system to generate TEOC.

Applied anatomy of a new approach of endoscopic technique in thyroid gland surgery.

OBJECTIVE: To explore the feasibility and safety of transtracheal assisted sublingual approach to totally endoscopic thyroidectomy by studying the anatomical approach and adjacent structures. METHODS: A total of 5 embalmed adult cadavers from Chengdu Medical College were dissected layer by layer in the cervical region, pharyngeal region, and mandible region, according to transtracheal assisted sublingual approach that was verified from the anatomical approach and planes. A total of 15 embalmed adult cadavers were dissected by arterial vascular casting technique, imaging scanning technique, and thin layer cryotomy. Then the vessel and anatomical structures of thyroid surgical region were analyzed qualitatively and quantitatively. Three-dimensional visualization of larynx artery was reconstructed by Autodesk 3ds Max 2010(32). Transtracheal assisted sublingual approach for totally endoscopic thyroidectomy was simulated on 5 embalmed adult cadavers. RESULTS: The sublingual observed access was located in the middle of sublingual region. The geniohyoid muscle, mylohyoid seam, and submental triangle were divided in turn in the middle to reach the plane under the plastima muscles. Superficial cervical fascia, anterior body of hyoid bone, and infrahyoid muscles were passed in sequence to reach thyroid gland surgical region. The transtracheal operational access was placed from the cavitas oris propria, isthmus faucium, subepiglottic region, laryngeal pharynx, and intermediate laryngeal cavit, and then passed from the top down in order to reach pars cervicalis tracheae where a sagittal incision was made in the anterior wall of cartilagines tracheales to reach a ascertained surgical region. CONCLUSION: Transtracheal assisted sublingual approach to totally endoscopic thyroidectomy is anatomically feasible and safe and can be useful in thyroid gland surgery.

Oxidative stress and metal ions effects on the cores of phycobilisomes in Synechocystis sp. PCC 6803.

Inactivation of the chlN gene in Synechocystis sp. PCC 6803 resulted in no chlorophyll and photosystems when the mutant was grown in darkness, providing an in vivo system to study the structure and function of phycobilisomes (PBSs). The effects of hydrogen peroxide (H2O2) and metal ions on the mutant PBSs in vivo were investigated by low temperature fluorescence emission measurement. H2O2 induced an obvious disassembly of the cores of PBSs and interruption of energy transfer from allophycocyanin to the terminal emitter. Among many metal ions only silver induced disassembly of the cores of PBSs. Our results demonstrated for the first time that the cores of PBSs act as targets in vivo for oxidative stress or silver induced damage.

[Impact of early-stage hepatic ischemia-reperfusion injury on other organs of rats].

OBJECTIVE: To investigate the influence of hepatic ischemia-reperfusion on other organs of rats during the early stage of injury. METHODS: Twenty-five healthy male SD rats were randomized equally into 5 groups according to the different time points in the course of hepatic vascular occlusion and reperfusion, namely pre-occlusion, the end of occlusion, and after 0.5, 2.0 and 6.0 h reperfusion, respectively. In each group the rats were killed to obtain samples at the specified time points. The contents of malondialdehyde (MDA) and superoxide dismutase (SOD) in the lung, kidney, pancreas and heart were measured in pre-occlusion and 6-hour reperfusion groups. The triphosphate (ATPase) activity in heart tissues, the contents of MDA and the activity of SOD in blood and the blood biochemistry were observed in different groups. RESULTS: The activity of SOD and ATPase were decreased (P<0.05) after the ischemia-reperfusion as compared with those before ischemia, but the contents of MDA, ALT, AST BUN, AMY and CK-MB increased significantly (P<0.05). CONCLUSION: Liver ischemia-reperfusion can induce injury to other organs at the early stage of reperfusion.

[Three-dimensional dynamic contrast-enhanced magnetic resonance angiography in liver transplantation].

OBJECTIVE: To investigate the clinical value of three-dimensional dynamic contrast-enhanced magnetic resonance (MR) angiography in the liver transplantation. METHODS: MR scanning was performed both before and after the operation in 9 patients elected for liver transplantation, and after three-dimensional reconstruction at a computer workstation, the three- dimensional images of the inferior vena cava, hepatic veins, portal vein and bile duct were obtained. RESULTS: The three- dimensional images could be rotated in space to show the size, shape, lining of the veins and anatomic relationships between each other. CONCLUSION: Three-dimensional dynamic contrast-enhanced MR angiography can be of value in liver transplantation.

Multiple organ injury at early stage of intestinal and hepatic ischemia-reperfusion in rats.

OBJECTIVE: To investigate the early-stage multiple organ injuries in rats subjected to intestinal and hepatic ischemia-reperfusion. METHODS: Seventy-five normal male Wistar rats were randomized equally into hepatic ischemia, intestinal ischemia and intestinal-hepatic ischemia groups. Before and at the end of occlusion (45 min), as well as at the time points of 0.5, 2.0 and 6.0 h during the reperfusion, respectively, 5 rats from each group were killed to obtain samples for determination of the contents of malondialdehyde (MDA), superoxide dismutase (SOD) in the blood, lung, kidney, pancreas and heart tissues, along with blood urea nitrogen (BUN), amylase (AMY), and creatine kinase MB (CK-MB). RESULTS: The activity of SOD was decreased (P<0.05) and MDA, BUN, AMY and CK-MB levels increased significantly (P<0.05) after ischemia-reperfusion as compared with those before ischemia. CONCLUSIONS: Intestinal and hepatic ischemia-reperfusion can induce injury of multiple organs at early stage. With the same duration of ischemia-reperfusion, intestinal ischemia may induce severer injury than hepatic ischemia.

[Application of ischemic preconditioning before hepatic vascular exclusion for resection of hepatocellular carcinoma].

OBJECTIVE: To assess the value of clinical application of ischemic preconditioning (IP) before hepatic vascular exclusion for resection of hepatocellular carcinoma (HCC) accompanied by cirrhosis and explore the possible mechanism underlying the protective effect of this maneuver. METHODS: Thirty-four consecutive patients with resectable HCC were randomized into IP group to receive IP with a 5-min ischemia followed by 5-min perfusion before hepatic vascular exclusion and the control group with simply hepatic vascular exclusion. The liver function, hepatic Fas mRNA expression, caspase-3 activity, apoptosis of the hepatocytes were compared between the two groups. RESULTS: In the IP group, the aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels on postoperative day 1, 3 and 7 were all significantly higher than those of the control group (t=6.985, P<0.01). The total bilirubin levels were also higher in the former group on postoperative day 3 and 7 (t=3.447, P<0.05). The IP group had higher albumin levels on postoperative day 1 than the control group (t=3.360, P<0.05). After 1 hour's reperfusion, the hepatic mRNA expression of Fas, caspase-3 activity and apoptotic sinusoidal endothelial cells were all significantly higher than those of the control group (t=3.771, P<0.05). CONCLUSION: IP has a protective effect on liver function after hepatic resection with hepatic vascular exclusion in HCC patients, possibly due to the inhibition of hepatocyte apoptosis by down-regulating hepatic Fas mRNA expression and caspase-3 activity, and is a convenient technique applicable in such operations as hepatic transplants and hepatectomy.

[Combined operations for patients with hepatic cancer complicated by portal hypertension].

OBJECTIVE: To study the feasibility and operative procedures of liver resection in combination with collateral devascularization for treating patients with hepatic cancer complicated by portal hypertension. METHODS: A retrospective analysis was conducted in 45 cases of hepatectomy for hepatic cancer in combination with portaazygous devascularization for portal hypertension from Jan. 1995 to Jan. 2002. RESULTS: Operative mortality was zero. The absolute survival rate in 1/2, 1, 2, 3, 4, 5, 6, and 7 years was 44/45(97.8%), 30/41(73.2%), 26/36 (72.2%), 13/27(48.1%), 10/19(52.6%), 5/13(38.5%), 1/7(14.3%), 0/2(0) respectively. During hospitalization, refractory ascites occurred in 1 case and hepatorenal syndrome in another. Upper gastrointestinal hemorrhage occurred in 2 cases during the follow-up period. In the 14 patients who died during the follow-up, 9 died of cancer recurrence, 4 of liver function failure, and 1 of upper gastrointestinal hemorrhage. CONCLUSION: Hepatectomy in combination with portaazygous devascularization for patients with liver cancer complicated by portal hypertension is safe and feasible.