The effect of caffeic acid phenethyl ester (CAPE) on metabolic enzymes including acetylcholinesterase,butyrylcholinesterase, glutathione S-transferase,lactoperoxidase, and carbonic anhydrase isoenzymes I,II, IX,and XII

Caffeic acid phenethyl ester (CAPE) is an active component of honeybee propolis extracts. Carbonic anhydrases (CAs, EC 4.2.1.1) are widespread and intensively studied metalloenzymes present in higher vertebrates including humans as many diverse isoforms. Acetylcholinesterase (AChE) is responsible for acetyl choline (ACh) hydrolysis and plays a fundamental role in nerve impulse transmission by terminating the action of the ACh neurotransmitter at cholinergic synapses and neuromuscular junctions. Butyrylcholinesterase (BChE) is another enzyme abundantly present in the liver and released into blood in a soluble form. Lactoperoxidase (LPO) is an enzyme involved in fighting pathogenic microorganisms whereas glutathione S-transferases (GSTs) are dimeric proteins present both in prokaryotic and eukaryotic organisms and involved in cellular detoxification mechanisms. In the present study, the inhibition effect of CAPE on human carbonic anhydrase (hCA) isoforms I, II, IX, and XII, AChE, BChE, LPO, and GST was evaluated. CAPE inhibited these enzymes with K_is in the range between micromolar to picomolar. The best inhibitory effect was observed against AChE and BChE.     

‘Birth defects’ of photosystem II make it highly susceptible to photodamage during chloroplast biogenesis

High solar flux is known to diminish photosynthetic growth rates, reducing biomass productivity and lowering disease tolerance. Photosystem II (PSII) of plants is susceptible to photodamage (also known as photoinactivation) in strong light, resulting in severe loss of water oxidation capacity and destruction of the water‐oxidizing complex (WOC). The repair of damaged PSIIs comes at a high energy cost and requires de novo biosynthesis of damaged PSII subunits, reassembly of the WOC inorganic cofactors and membrane remodeling. Employing membrane‐inlet mass spectrometry and O₂‐polarography under flashing light conditions, we demonstrate that newly synthesized PSII complexes are far more susceptible to photodamage than are mature PSII complexes. We examined these ‘PSII birth defects’ in barley seedlings and plastids (etiochloroplasts and chloroplasts) isolated at various times during de‐etiolation as chloroplast development begins and matures in synchronization with thylakoid membrane biogenesis and grana membrane formation. We show that the degree of PSII photodamage decreases simultaneously with biogenesis of the PSII turnover efficiency measured by O₂‐polarography, and with grana membrane stacking, as determined by electron microscopy. Our data from fluorescence, Q_B‐inhibitor binding, and thermoluminescence studies indicate that the decline of the high‐light susceptibility of PSII to photodamage is coincident with appearance of electron transfer capability Q_A^? → Q_B during de‐etiolation. This rate depends in turn on the downstream clearing of electrons upon buildup of the complete linear electron transfer chain and the formation of stacked grana membranes capable of longer‐range energy transfer.     

pH dependence of the donor side reactions in Ca2+-depleted photosystem II

We have studied how low pH affects the water-oxidizing complex in Photosystem II when depleted of the essential Ca(2+) ion cofactor. For these samples, it was found that the EPR signal from the Y(Z)(*) radical decays faster at low pH than at high pH. At 20 degrees C, Y(Z)(*) decays with biphasic kinetics. At pH 6.5, the fast phase encompasses about 65% of the amplitude and has a lifetime of approximately 0.8 s, while the slow phase has a lifetime of approximately 22 s. At pH 3.9, the kinetics become totally dominated by the fast phase, with more than 90% of the signal intensity operating with a lifetime of approximately 0.3 s. The kinetic changes occurred with an approximate pK(a) of 4.5. Low pH also affected the induction of the so-called split radical EPR signal from the S(2)Y(Z)(*) state that is induced in Ca(2+)-depleted PSII membranes because of an inability of Y(Z)(*) to oxidize the S(2) state. At pH 4.5, about 50% of the split signal was induced, as compared to the amplitude of the signal that was induced at pH 6.5-7, using similar illumination conditions. Thus, the split-signal induction decreased with an apparent pK(a) of 4.5. In the same samples, the stable multiline signal from the S(2) state, which is modified by the removal of Ca(2+), was decreased by the illumination to the same extent at all pHs. It is proposed that decreased induction of the S(2)Y(Z)(*) state at lower pH was not due to inability to oxidize the modified S(2) state induced by the Ca(2+) depletion. Instead, we propose that the low pH makes Y(Z)(*) able to oxidize the S(2) state, making the S(2) --> S(3) transition available in Ca(2+)-depleted PSII. Implications of these results for the catalytic role of Ca(2+) and the role of proton transfer between the Mn cluster and Y(Z) during oxygen evolution is discussed.     

Comparison of Conventional versus Steerable-Catheter Guided Coronary Sinus Lead Positioning in Patients Undergoing Cardiac Resynchronization Device Implantation

Objectives

The aim of this study was to compare conventional versus steerable catheter guided coronary sinus (CS) cannulation in patients with advanced heart failure undergoing cardiac resynchronization therapy (CRT).

Background

Steerable catheter guided coronary sinus cannulation could reduce fluoroscopy time and contrast medium use during CRT implantation.

Methods

176 consecutive patients with ischemic and non-ischemic heart failure undergoing CRT implantation from January 2008 to December 2012 at the University Hospital of Cologne were identified. During the study period two concurrent CS cannulation techniques were used: standard CS cannulation technique (standard-group, n = 113) and CS cannulation using a steerable electrophysiology (EP) catheter (EPCath-group, n = 63). Propensity-score matched pairs of conventional and EP-catheter guided CS cannulation made up the study population (n = 59 pairs). Primary endpoints were total fluoroscopy time and contrast medium amount used during procedure.

Results

The total fluoroscopy time was 30.9 min (interquartile range (IQR), 19.9–44.0 min) in the standard-group and 23.4 min (IQR, 14.2-34-2 min) in the EPCath-group (p = 0.011). More contrast medium was used in the standard-group (60.0 ml, IQR, 30.0–100 ml) compared to 25.0 ml (IQR, 20.0–50.0 ml) in the EPCath-group (P<0.001).

Conclusions

Use of steerable EP catheter was associated with significant reduction of fluoroscopy time and contrast medium use in patients undergoing CRT implantation.     

Effects of Selenium and Vitamin E,in Addıtıon to Melatonin,Against Oxidative Stress Caused by Cadmium in Rats

The present study was carried to evaluate the protective effects of melatonin alone and vitamin E with selenium combination against high dose cadmium-induced oxidative stress in rats. The control group received subcutanous physiological saline. The first study group administered cadmium chloride (CdCl₂) by subcutaneous injection of dose of 1 mg/kg. The second study group administered cadmium plus vitamin E with selenium (1 mg/kg sodium selenite with 60 mg/kg vitamin E); the third study group administered cadmium plus 10 mg/kg melatonin (MLT); the fourth study group administered CdCl₂ plus a combination of melatonin in addition to vitamin E and selenium for a month. Determination levels of plasma malondialdehyde (MDA), glutathione peroxidase (GSH-Px), blood superoxide dismutase (SOD), creatinine alanine transaminase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), blood urea nitrogen (BUN), and urea were measured in serum. In only CdCl₂ administered group, the MDA, creatinine, ALT, AST, ALP, and urea levels in the serum were significantly higher than the control group (p < 0.05). Whereas in all other groups, this values were significantly lower than the only CdCl₂ administered group (p < 0.05). Erythrocytes GSH-Px, serum SOD activities of only CdCl₂ received group were significantly lower than the control group (p < 0.05). In conclusion, vitamin E + Se, melatonin and vitamin E, and Se, in addition to MLT combinations, had protective effects against high dose cadmium-induced oxidative damage.     

Mutations in autism susceptibility candidate 2 (AUTS2) in patients with mental retardation

We report on three unrelated mentally disabled patients, each carrying a de novo balanced translocation that truncates the autism susceptibility candidate 2 (AUTS2) gene at 7q11.2. One of our patients shows relatively mild mental retardation; the other two display more profound disorders. One patient is also physically disabled, exhibiting urogenital and limb malformations in addition to severe mental retardation. The function of AUTS2 is presently unknown, but it has been shown to be disrupted in monozygotic twins with autism and mental retardation, both carrying a translocation t(7;20)(q11.2;p11.2) (de la Barra et al. in Rev Chil Pediatr 57:549–554, 1986; Sultana et al. in Genomics 80:129–134, 2002). Given the overlap of this autism/mental retardation (MR) phenotype and the MR-associated disorders in our patients, together with the fact that mapping of the additional autosomal breakpoints involved did not disclose obvious candidate disease genes, we ascertain with this study that AUTS2 mutations are clearly linked to autosomal dominant mental retardation.     

Comamonas testosteroni bacteremia in a patient with perforated acute appendicitis. Short communication

Comamonas testosteroni is an uncommon isolate in the clinical laboratory as a human pathogen. C. testosteroni most commonly emerges in abdominal pathologies especially in perforated appendicitis. In Turkey we report first time a case of bacteremia due to this organism, in a 22-year-old man with perforated acute appendicitis. The organism was shown to be susceptible to routine antibiotics so it was easily eliminated even after having caused a bacteremia.     

PHOTOSYSTEM II PROTEIN33, a Protein Conserved in the Plastid Lineage,Is Associated with the Chloroplast Thylakoid Membrane and Provides Stability to Photosystem II Supercomplexes in Arabidopsis

Photosystem II (PSII) is a multiprotein complex that catalyzes the light-driven water-splitting reactions of oxygenic photosynthesis. Light absorption by PSII leads to the production of excited states and reactive oxygen species that can cause damage to this complex. Here, we describe Arabidopsis (Arabidopsis thaliana) At1g71500, which encodes a previously uncharacterized protein that is a PSII auxiliary core protein and hence is named PHOTOSYSTEM II PROTEIN33 (PSB33). We present evidence that PSB33 functions in the maintenance of PSII-light-harvesting complex II (LHCII) supercomplex organization. PSB33 encodes a protein with a chloroplast transit peptide and one transmembrane segment. In silico analysis of PSB33 revealed a light-harvesting complex-binding motif within the transmembrane segment and a large surface-exposed head domain. Biochemical analysis of PSII complexes further indicates that PSB33 is an integral membrane protein located in the vicinity of LHCII and the PSII CP43 reaction center protein. Phenotypic characterization of mutants lacking PSB33 revealed reduced amounts of PSII-LHCII supercomplexes, very low state transition, and a lower capacity for nonphotochemical quenching, leading to increased photosensitivity in the mutant plants under light stress. Taken together, these results suggest a role for PSB33 in regulating and optimizing photosynthesis in response to changing light levels.PSII is a multiprotein complex in plants with 31 identified polypeptides (Wegener et al., 2011; Pagliano et al., 2013). It is associated with an extrinsic trimeric light-harvesting complex (LHC), forming the PSII-LHCII supercomplex. The PSII complex performs a remarkable biochemical reaction, the oxidation of water using light energy from the sun, which profoundly contributes to the overall biomass accumulation in the biosphere (Barber et al., 2004). Consequently, the stability and functional integrity of the PSII-LHCII supercomplex is crucially important for photosynthetic function. The energy of a photon, either absorbed directly by PSII or indirectly via energy transfer from adjacent antenna chlorophyll (Chl) molecules, excites the PSII reaction center P680. The excited state, P680*, can transfer an electron to pheophytin, producing the most powerful oxidant known in biology, P680⁺, which can remove electrons from water. Excessive input of excitation energy into PSII saturates the electron transfer system and causes either acceptor or donor site limitation in the complex. This results in increased production of reactive oxygen species (ROS): singlet oxygen at the PSII donor side and superoxide at the acceptor side (Munné-Bosch et al., 2013). Several protective mechanisms have been documented that decrease the production of singlet oxygen at the PSII donor side in photosynthetic eukaryotes. Notably, reducing energy transfer from LHC to PSII via nonphotochemical quenching (NPQ) is a key avoidance mechanism (Ruban and Murchie, 2012).Despite years of intensive study of PSII structure and function, new proteins that are associated with the PSII complex continue to be discovered, including an increasing number involved in the stability and organization of PSII-LHCII supercomplexes (García-Cerdán et al., 2011; Lu et al., 2011a; Wegener et al., 2011). Two complementary approaches (Merchant et al., 2007; Lu et al., 2008, 2011b; Ajjawi et al., 2010) that utilize phylogenomics (GreenCut) and large-scale phenotypic mutant screening (Chloroplast 2010 Project; http://www.plastid.msu.edu/) were employed by our groups to discover novel plant proteins with roles in photosynthesis. GreenCut identifies proteins found only in photosynthetic organisms, and it is likely that many of them are involved in biochemical processes associated with the structure, assembly, or function of the photosynthetic apparatus and the chloroplast that houses it (Merchant et al., 2007; Karpowicz et al., 2011). The Chloroplast 2010 Project was a large-scale reverse-genetic mutant screen in which thousands of homozygous Arabidopsis (Arabidopsis thaliana) transfer DNA (T-DNA) insertion lines were analyzed for defects in the rise and decay kinetics of Chl fluorescence (Lu et al., 2008, 2011a, 2011b; Ajjawi et al., 2010).The GreenCut and Chloroplast 2010 approaches both identified the Arabidopsis At1g71500 locus as encoding a protein of unknown function with potential relevance to photosynthesis. In this work, we demonstrate that plant lines carrying three independent mutations at this locus display severe light-induced photoinhibition due to a less stable supramolecular organization of PSII. Biochemical analyses revealed that this protein is associated with PSII complexes, and since the last described PSII protein was called PHOTOSYSTEM II PROTEIN32 (PSB32), we named the gene PSB33. The nuclear genome-encoded PSB33 is predicted to have a chloroplast transit peptide and a transmembrane domain. The biochemical analyses presented below indicate that PSB33 is required for the proper interaction and stability of PSII-LHCII supercomplexes and, in turn, in regulating photosynthesis in response to fluctuating light levels.