Effective separation of maslinic acid and oleanolic acid from olive pomace using high-speed shear off-line coupled with high-speed countercurrent chromatography and their antibacterial activity test.

In this work, a high-speed shear extraction off-line coupling high-speed countercurrent chromatography method was developed to separate maslinic acid and oleanolic acid from olive pomace. To improve extraction efficiency, the polar disparity between maslinic acid and oleanolic acid necessitated the concurrent utilization of both polar and non-polar solvents during high-speed shear extraction. Then, the high-speed shear extraction was directly feed to high-speed countercurrent chromatography for subsequently separation. A total of 250 min were needed to complete the extraction and separation process. This yielded two molecules from 3.3 g of defatted olive pomace: 7.2 mg of 93.8 % pure maslinic acid and 2.3 mg of 90.1 % pure oleanolic acid, both determined by HPLC at 210 nm. Furthermore, the compounds exhibited inhibitory activity against Escherichia coli and Staphylococcus aureus. At a concentration of 100 µg/mL, its efficacy in inhibiting hyaluronidase was comparable to that of the standard drug indomethacin. Compared with the conventional separation method, this coupled technique reduced the whole time due to the direct injection of sample extraction solution. This technique provides a useful approach for the separation of natural products with significant polarity differences.

Protein S-Nitrosylation Controls Glycogen Synthase Kinase 3ß Function Independent of Its Phosphorylation State.

RATIONALE: GSK-3ß (glycogen synthase kinase 3ß) is a multifunctional and constitutively active kinase known to regulate a myriad of cellular processes. The primary mechanism to regulate its function is through phosphorylation-dependent inhibition at serine-9 residue. Emerging evidence indicates that there may be alternative mechanisms that control GSK-3ß for certain functions. OBJECTIVES: Here, we sought to understand the role of protein S-nitrosylation (SNO) on the function of GSK-3ß. SNO-dependent modulation of the localization of GSK-3ß and its ability to phosphorylate downstream targets was investigated in vitro, and the network of proteins differentially impacted by phospho- or SNO-dependent GSK-3ß regulation and in vivo SNO modification of key signaling kinases during the development of heart failure was also studied. METHODS AND RESULTS: We found that GSK-3ß undergoes site-specific SNO both in vitro, in HEK293 cells, H9C2 myoblasts, and primary neonatal rat ventricular myocytes, as well as in vivo, in hearts from an animal model of heart failure and sudden cardiac death. S-nitrosylation of GSK-3ß significantly inhibits its kinase activity independent of the canonical phospho-inhibition pathway. S-nitrosylation of GSK-3ß promotes its nuclear translocation and access to novel downstream phosphosubstrates which are enriched for a novel amino acid consensus sequence motif. Quantitative phosphoproteomics pathway analysis reveals that nuclear GSK-3ß plays a central role in cell cycle control, RNA splicing, and DNA damage response. CONCLUSIONS: The results indicate that SNO has a differential effect on the location and activity of GSK-3ß in the cytoplasm versus the nucleus. SNO modification of GSK-3ß occurs in vivo and could contribute to the pathobiology of heart failure and sudden cardiac death.

The clinical-psychological features of functional dyspepsia patients with weight loss: a multi-center study from China.

AIMS: To investigate the clinical features, appetite, quality of life (QOL), and their associated psychological factors of functional dyspepsia (FD) patients with weight loss. METHODS: For a multicenter study, FD patients were recruited and divided into two groups according to the degree of weight changes during the previous 12 months or less with the onset of dyspepsia symptoms: Group A (≥5%) and Group B (<5%). Patients were evaluated based on the Nepean dyspepsia index (NDI), appetite questionnaire, Hamilton Rating Scale of Anxiety/Depression (HAMA/HAMD). RESULTS: The body mass index in Group A was lower than in Group B, while, the frequency of physician visits in Group A was higher than in Group B. There were no differences in the total scores of NDI-symptom checklist or the items of intensity and bothersomeness between them (p > 0.05), but the frequency item for Group A was significantly higher than Group B (p = 0.035). The incidence of anxiety or depression, the proportion of poor or very poor appetite for Group A was higher than those for Group B (p < 0.05). Subscale scores of the NDI-QOL for Group A were significantly lower than those for Group B (p < 0.05). CONCLUSIONS: FD patients with weight loss have lower BMI, more frequent physician visits, higher psychological disorders, poorer appetite and QoL.

Incidence and psychological-behavioral characteristics of refractory functional dyspepsia: a large, multi-center, prospective investigation from China.

AIM: To explore the incidence and psychological and behavioral characteristics of refractory functional dyspepsia (RFD) in China. METHODS: The subjects of this study were 1341 new outpatients with functional dyspepsia (FD) who were diagnosed according to the Rome III criteria at four hospitals in Guangdong Province between June and September 2012, and 100 healthy volunteers. All subjects completed questionnaires and scales administered. RESULTS: Three-hundred and twenty-seven of the 1341 patients with FD had RFD (24.4%). Patients with RFD had a longer disease duration and a more severe form of the disease than patients with non-refractory FD (NRFD). The prevalence of depression and anxiety symptoms was higher in patients with RFD than in patients with NRFD. The prevalence of unhealthy eating behaviors, lack of physical activity, and sleeping disorders was higher in patients with RFD than in patients with NRFD. Patients with RFD sought medical advice on more occasions and spent more money on treatment than patients with NRFD. Finally, patients with RFD had poorer quality of life than patients with NRFD. CONCLUSION: RFD is not rare in clinical practice and should get attention by patients and doctors because of its long duration, severe symptoms, and associations with abnormal psychology and poor quality of life.

Unhealthy dietary behavior in refractory functional dyspepsia: a multicenter prospective investigation in China.

OBJECTIVE: To determine the association of dietary behavior with refractory functional dyspepsia (RFD) and its subtypes in Chinese patients. METHODS: The medical records of patients admitted to the Outpatient Department of Gastroenterology of four hospitals in Mainland China for upper gastrointestinal (GI) symptoms from June to September 2012 were reviewed and their characteristics were collected. Functional dyspepsia (FD) was diagnosed based on the Rome III criteria. RFD was defined as FD with continuous symptoms for at least 6 months that was unresponsive to at least two kinds of medications. Another 100 healthy volunteers were included as controls. The participants' dietary behaviors were investigated using a questionnaire survey. RESULTS: Overall, 1341 FD patients were enrolled in the study, including 327 RFD and 1014 non-RFD (NRFD). Unhealthy dietary behaviors were more prevalent in both RFD and NRFD than in the healthy controls. Skipping meals, eating extra meals and a preference to sweet food and gas-producing food were more common in the RFD patients. Compared with NRFD, RFD-epigastric pain syndrome (EPS) patients preferred spicy food, whereas those with postprandial distress syndrome (PDS) preferred sweet food and gas-producing food, and those with both EPS and PDS were found to skip meals and take extra meals more often. Logistic regression analysis showed that skipping meals, eating extra meals and a preference to sweet food and gas-producing food were risk factors for RFD. CONCLUSION: Unhealthy dietary behaviors, especially skipping meals, eating extra meals and a preference to sweet food and gas-producing food, were correlated with RFD and its subtypes.

Incidence and clinical features of hyperlipidemic acute pancreatitis from Guangdong, China: a retrospective multicenter study.

OBJECTIVE: This study aimed to investigate the clinical features and incidence trends of hyperlipidemic acute pancreatitis (HLAP) of multicenter studies in Guangdong, China, for 15 years. METHODS: The medical records of 1582 patients with acute pancreatitis who were admitted to 4 general hospitals of Guangdong from January 1990 to December 2005 were reviewed. The inpatient medical and radiologic records were reviewed to determine clinical features, severity, complications, mortality, and recurrence rate. RESULTS: A total of 7.8% (123/1582) patients met the HLAP criteria. Incidence of HLAP was approximately 2.6 times increased during 15 years (3.4% in 1990-1994, 5.9% in 1995-1999, and 8.9% in 2000-2005, respectively) and ranged from 3.3% to 15.5% in 4 hospitals across Guangdong. A history of diabetes was present in 31.7% and alcohol use in 18.7%. The mean (SD) triglyceride levels were 13.6 (7.2) mmol/L. Amylase was elevated higher than normal in 81.2% but only 2 times normal in 17.1% and 3 times normal in 37.6%. The frequency of severe acute pancreatitis, organ dysfunction, rate of recurrence, and mortality of HLAP was significantly higher than biliary-induced pancreatitis. CONCLUSIONS: The incidence of HLAP had significantly increased during the past 15 years with a clear geographic variation and remarkable severity and recurrent trend.

Cysteine oxidative posttranslational modifications: emerging regulation in the cardiovascular system.

In the cardiovascular system, changes in oxidative balance can affect many aspects of cellular physiology through redox-signaling. Depending on the magnitude, fluctuations in the cell's production of reactive oxygen and nitrogen species can regulate normal metabolic processes, activate protective mechanisms, or be cytotoxic. Reactive oxygen and nitrogen species can have many effects including the posttranslational modification of proteins at critical cysteine thiols. A subset can act as redox-switches, which elicit functional effects in response to changes in oxidative state. Although the general concepts of redox-signaling have been established, the identity and function of many regulatory switches remains unclear. Characterizing the effects of individual modifications is the key to understand how the cell interprets oxidative signals under physiological and pathological conditions. Here, we review the various cysteine oxidative posttranslational modifications and their ability to function as redox-switches that regulate the cell's response to oxidative stimuli. In addition, we discuss how these modifications have the potential to influence other posttranslational modifications' signaling pathways though cross-talk. Finally, we review the increasing number of tools being developed to identify and quantify the various cysteine oxidative posttranslational modifications and how this will advance our understanding of redox-regulation.

Redox regulation of mitochondrial ATP synthase.

Reversible cysteine oxidative post-translational modifications (Ox-PTMs) represent an important mechanism to regulate protein structure and function. In mitochondria, redox reactions can modulate components of the electron transport chain (ETC), the F(1)F(0)-ATP synthase complex, and other matrix proteins/enzymes. Emerging evidence has linked Ox-PTMs to mitochondrial dysfunction and heart failure, highlighting some potential therapeutic avenues. Ox-PTMs can modify a variety of amino acid residues, including cysteine, and have the potential to modulate the function of a large number of proteins. Among this group, there is a selected subset of amino acid residues that can function as redox switches. These unique sites are proposed to monitor the cell's oxidative balance through their response to the various Ox-PTMs. In this review, the role of Ox-PTMs in the regulation of the F(1)F(0)-ATP synthase complex is discussed in the context of heart failure and its possible clinical treatment.

The Ser/Thr protein kinase AfsK regulates polar growth and hyphal branching in the filamentous bacteria Streptomyces.

In cells that exhibit apical growth, mechanisms that regulate cell polarity are crucial for determination of cellular shape and for the adaptation of growth to intrinsic and extrinsic cues. Broadly conserved pathways control cell polarity in eukaryotes, but less is known about polarly growing prokaryotes. An evolutionarily ancient form of apical growth is found in the filamentous bacteria Streptomyces, and is directed by a polarisome-like complex involving the essential protein DivIVA. We report here that this bacterial polarization machinery is regulated by a eukaryotic-type Ser/Thr protein kinase, AfsK, which localizes to hyphal tips and phosphorylates DivIVA. During normal growth, AfsK regulates hyphal branching by modulating branch-site selection and some aspect of the underlying polarisome-splitting mechanism that controls branching of Streptomyces hyphae. Further, AfsK is activated by signals generated by the arrest of cell wall synthesis and directly communicates this to the polarisome by hyperphosphorylating DivIVA. Induction of high levels of DivIVA phosphorylation by using a constitutively active mutant AfsK causes disassembly of apical polarisomes, followed by establishment of multiple hyphal branches elsewhere in the cell, revealing a profound impact of this kinase on growth polarity. The function of AfsK is reminiscent of the phoshorylation of polarity proteins and polarisome components by Ser/Thr protein kinases in eukaryotes.

Redox regulation of mitochondrial ATP synthase: implications for cardiac resynchronization therapy.

RATIONALE: Cardiac resynchronization therapy (CRT) is an effective clinical treatment for heart failure patients with conduction delay, impaired contraction, and energetics. Our recent studies have revealed that mitochondrial posttranslational modifications (PTM) may contribute to its benefits, motivating the present study of the oxidative regulation of mitochondrial ATP synthase. OBJECTIVES: We tested whether CRT alteration of ATP synthase function is linked to cysteine (Cys) oxidative PTM (Ox-PTM) of specific ATP synthase subunits. METHODS AND RESULTS: Canine left ventricular myocardium was collected under conditions to preserve Ox-PTM from control, dyssynchronous heart failure (DHF), or hearts that had undergone CRT. In-gel ATPase activity showed that CRT increased ATPase activity by approximately 2-fold (P<0.05) over DHF, approaching control levels, and this effect was recapitulated with a reducing agent. ATP synthase function and 3 Ox-PTM: disulfide bond, S-glutathionylation and S-nitrosation were assessed. ATP synthase from DHF hearts contained 2 novel disulfide bonds, between ATP synthase α subunits themselves and between α and γ subunits, both of which were decreased in CRT hearts (4.38 ± 0.13- and 4.23 ± 0.36-fold, respectively, P<0.01). S-glutathionylation of ATP synthase α subunit occurred in DHF hearts and was decreased by CRT (1.56 ± 0.16-fold, P<0.04). In contrast, S-nitrosation of ATP synthase α subunit in DHF hearts was lower than in CRT hearts (1.53 ± 0.19-fold, P<0.05). All modifications occurred at ATP synthase α subunit Cys294 and Cys to Ser mutation indicated that this residue is critical for ATP synthase function. CONCLUSIONS: A selective Cys in ATP synthase α subunit is targeted by multiple Ox-PTM suggesting that this Cys residue may act as a redox sensor modulating ATP synthase function.

Site-mapping of in vitro S-nitrosation in cardiac mitochondria: implications for cardioprotection.

S-nitrosation (SNO) of mitochondrial protein cysteines can be cardioprotective. Several targets have been implicated, yet the scope and identification of specific residues has not been fully assessed. To address this, a comprehensive assessment of mitochondrial SNO-modifiable cysteines was performed to determine nitric oxide (NO) susceptible pathways and identify novel mechanisms of oxidative cardioprotection. The biotin switch assay and mass spectrometry were used on rat cardiac mitochondrial lysates treated with the nitric oxide donor, S-nitrosoglutathione, and controls (n=3) to map 83 SNO-modified cysteine residues on 60 proteins. Of these, three sites have been reported, 30 sites are new to 21 proteins previously known to be S-nitrosated but which lacked site-specific information and 50 sites were found on 39 proteins not previously implicated in SNO pathways. The SNO-modifications occurred in only a subset of available cysteines, indicating a specific targeted effect. Functional annotation and site-specificity analysis revealed a twofold greater nitric oxide-susceptibility for proteins involved in transport; including regulators of mitochondrial permeability transition suggesting SNO-regulation and a possible protective mechanism. Additionally, we identified many novel SNO-modified proteins with cardioprotective potential involved in the electron transport chain, tricarboxylic acid cycle, oxidative stress defense, fatty acid and amino acid metabolism. These findings suggest that SNO-modification may represent a novel mechanism for the regulation of oxidative phosphorylation and/or cell death. S-nitrosation of mitochondrial permeability transition-associated proteins represents an intriguing potential link to cardioprotection.

Domains involved in the in vivo function and oligomerization of apical growth determinant DivIVA in Streptomyces coelicolor.

The coiled-coil protein DivIVA is a determinant of apical growth and hyphal branching in Streptomyces coelicolor. We have investigated the properties of this protein and the involvement of different domains in its essential function and subcellular targeting. In S. coelicolor cell extracts, DivIVA was present as large oligomeric complexes that were not strongly membrane associated. The purified protein could self-assemble into extensive protein filaments in vitro. Two large and conspicuous segments in the amino acid sequence of streptomycete DivIVAs not present in other homologs, an internal PQG-rich segment and a carboxy-terminal extension, are shown to be dispensable for the essential function in S. coelicolor. Instead, the highly conserved amino-terminal of 22 amino acids was required and affected establishment of new DivIVA foci and hyphal branches, and an essential coiled-coil domain affected oligomerization of the protein.

Assemblies of DivIVA mark sites for hyphal branching and can establish new zones of cell wall growth in Streptomyces coelicolor.

Time-lapse imaging of Streptomyces hyphae revealed foci of the essential protein DivIVA at sites where lateral branches will emerge. Overexpression experiments showed that DivIVA foci can trigger establishment of new zones of cell wall assembly, suggesting a key role of DivIVA in directing peptidoglycan synthesis and cell shape in Streptomyces.

AtNUDT7, a negative regulator of basal immunity in Arabidopsis, modulates two distinct defense response pathways and is involved in maintaining redox homeostasis.

Plants have evolved complicated regulatory systems to control immune responses. Both positive and negative signaling pathways interplay to coordinate development of a resistance response with the appropriate amplitude and duration. AtNUDT7, a Nudix domain-containing protein in Arabidopsis (Arabidopsis thaliana) that hydrolyzes nucleotide derivatives, was found to be a negative regulator of the basal defense response, and its loss-of-function mutation results in enhanced resistance to infection by Pseudomonas syringae. The nudt7 mutation does not cause a strong constitutive disease resistance phenotype, but it leads to a heightened defense response, including accelerated activation of defense-related genes that can be triggered by pathogenic and nonpathogenic microorganisms. The nudt7 mutation enhances two distinct defense response pathways: one independent of and the other dependent on NPR1 and salicylic acid accumulation. In vitro enzymatic assays revealed that ADP-ribose and NADH are preferred substrates of NUDT7, and the hydrolysis activity of NUDT7 is essential for its biological function and is sensitive to inhibition by Ca(2+). Further analyses indicate that ADP-ribose is not likely the physiological substrate of NUDT7. However, the nudt7 mutation leads to perturbation of cellular redox homeostasis and a higher level of NADH in pathogen-challenged leaves. The study suggests that the alteration in cellular antioxidant status caused by the nudt7 mutation primes the cells for the amplified defense response and NUDT7 functions to modulate the defense response to prevent excessive stimulation.

Isolation and proteomic analysis [corrected] of cell wall-deficient Haematococcus pluvialis mutants.

The green alga Haematococcus pluvialis has a plant-like cell wall consisting of glycoproteins and cellulose that is modified during the cell cycle and under various conditions. These features allow Haematococcus to be used as a model organism for studying cell wall biology. Development of the Haematococcus model is hampered by the absence of mutants that could provide insight into the biosynthesis and assembly of wall components. Haematococcus mutants (WM#537 and WM#2978) (WM--wall mutant) with defective cell walls were obtained by chemical mutagenesis. WM#537 features a secondary wall of considerably reduced thickness, whereas WM#2978 possesses a somewhat reduced secondary wall with little intervening space between the wall and plasmalemma. 2-DE revealed that a majority of the cell wall proteins were present in the wild-type and mutant cell walls throughout the cell cycle. PMF identified 55 wall protein orthologs from these strains, including a subset of induced proteins known to be involved in wall construction, remodeling, and defense. Down-regulation of certain wall proteins in the two mutants was associated with the wall defects, whereas overexpression of other proteins may have compensated for the defective walls in the two mutants.

Proteomic analysis of molecular response to oxidative stress by the green alga Haematococcus pluvialis (Chlorophyceae).

Rapidly growing, green motile flagellates of Haematococcus pluvialis can transform into enlarged red resting cysts (aplanospores) under oxidative stress conditions. However, it is not known what initial molecular defense mechanisms occur in response to oxidative stress, and may ultimately lead to cellular transformation. In this study, global-expression profiling of cellular proteins in response to stress was analyzed by two-dimensional gel electrophoresis, image analysis, and peptide mass fingerprinting. Oxidative stress was induced in cultures of green flagellates by addition of acetate and Fe2+, and exposure to excess light intensity. Overall, 70 proteins were identified with altered expression patterns following stress induction. Some key proteins involved in photosynthesis and nitrogen assimilation were down-regulated, whereas some mitochondrial respiratory proteins were transiently up-regulated after the onset of stress. Most of the identified proteins, particularly those from the families of superoxide dismutase, catalase, and peroxidase, were transiently up-regulated, but reverted to down-regulation during the 6 days of stress. On the other hand, cellular accumulation of the antioxidant astaxanthin occurred well after initiation of oxidative stress and reached its maximum cellular level after six or more days of stress. It appears that the early stress response involves multiple enzymatic defense processes that play a critical role upon onset of stress and also during the early transition of green vegetative cells to red cysts. As cyst development continues, the intensive, enzyme-mediated initial responses were largely replaced in mature red cysts by accumulation of the molecular antioxidant astaxanthin. This study provides the first direct evidence for a massive, and concerted up-regulation of multiple antioxidative defense mechanisms, both spatially and temporarily, to protect H. pluvialis cells against oxidative stress.

Cell wall proteomics of the green alga Haematococcus pluvialis (Chlorophyceae).

The green microalga Haematococcus pluvialis can synthesize and accumulate large amounts of the ketocarotenoid astaxanthin, and undergo profound changes in cell wall composition and architecture during the cell cycle and in response to environmental stresses. In this study, cell wall proteins (CWPs) of H. pluvialis were systematically analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) coupled with peptide mass fingerprinting (PMF) and sequence-database analysis. In total, 163 protein bands were analyzed, which resulted in positive identification of 81 protein orthologues. The highly complex and dynamic composition of CWPs is manifested by the fact that the majority of identified CWPs are differentially expressed at specific stages of the cell cycle along with a number of common wall-associated 'housekeeping' proteins. The detection of cellulose synthase orthologue in the vegetative cells suggested that the biosynthesis of cellulose occurred during primary wall formation, in contrast to earlier observations that cellulose was exclusively present in the secondary wall of the organism. A transient accumulation of a putative cytokinin oxidase at the early stage of encystment pointed to a possible role in cytokinin degradation while facilitating secondary wall formation and/or assisting in cell expansion. This work represents the first attempt to use a proteomic approach to investigate CWPs of microalgae. The reference protein map constructed and the specific protein markers obtained from this study provide a framework for future characterization of the expression and physiological functions of the proteins involved in the biogenesis and modifications in the cell wall of Haematococcus and related organisms.