The methodology and findings of these studies were critically rev

The methodology and findings of these studies were critically reviewed and discussed. Because of the small number of studies, meta-analysis was only conducted for studies that used behavioral PM measures in adults to integrate findings. PM deficits were found to be commonly reported by patients with CHI and their significant others and they could be identified using behavioral measures in adults, children and adolescents with CHI. However, more work is needed to clarify the nature and mechanisms of these deficits. Although some promising results have been reported by studies that evaluated PM treatment, most studies lack tight experimental control and used only a small number of participants. The paper concluded with some suggestions for future research. (C) 2011 Elsevier Ltd. All rights reserved.”
“Purpose: To evaluate results of carotid endarterectomy (CEA) in diabetic patients in a large single-center experience.

Methods: Over a 13-year period ending in December 2008, 4305 consecutive CEAs in 3573 patients were performed. All patients were prospectively enrolled in a dedicated database. Interventions were performed in diabetic patients in 883 cases (20.5%; group 1) and in nondiabetics in the remaining 3422 (79.5%; group 2). Early results in terms of 30-day stroke and death rates were analyzed and compared.

Follow-up results were analyzed with Kaplan-Meier curves and compared with log-rank test.

Results: Diabetic patients were more likely to be females and to have coronary artery disease, peripheral arterial this website disease, hyperlipemia, and arterial hypertension Protein tyrosine phosphatase than nondiabetics. There were no differences between the two groups in terms of preoperative clinical status or degree of carotid stenosis. Interventions were performed under general anesthesia with somatosensory-evoked potentials (SEPs) monitoring in

67% of the patients in both groups, while the remaining interventions were performed under clinical monitoring. Shunt insertion (14% and 11%, respectively) and patch closure rates (79% and 76%, respectively) were similar between the two groups. There were no differences between the two groups in terms of neurological outcomes, while the mortality rate was higher in group 1 than in group 2 (P = .002; odds ratio [OR], 3.5; 95% confidence interval [CI], 1.5-8.3); combined 30-day stroke and death rate was significantly higher in group 1 (2%) than in group 2 (0.9%; P = .006; 95% CI, 1.2-3.9; OR, 2.2). At univariate analysis, perioperative risk of stroke and death in diabetic patients was significantly higher in patients undergoing intervention with SEP cerebral monitoring (95% CI, 0.9-39.9; OR, 5.9; P = .01), and this was also confirmed by multivariate analysis (95% CI, 1.1-23.1; OR, 8.

METHODS: The data from 196 patients were reviewed retrospectively

METHODS: The data from 196 patients were reviewed retrospectively. All patients had iatrogenic sciatic nerve injuries at the buttock and thigh levels and were evaluated and treated at the Louisiana State University Health Sciences Center between the years 1968 and 1999. One hundred sixty-four

of these patients had injuries caused by injections at the buttock level, 15 sustained sciatic nerve injuries after a total hip arthroplasty, and 17 had iatrogenic damage at the thigh level.

RESULTS: Patients with severe motor deficits underwent neurolysis if they had positive nerve Bleomycin purchase action potentials, and end-to-end anastomosis or grafting if the nerve action potentials were negative. Operations were performed on 64 patients with injection injuries at the buttock level, on 15 with iatrogenic damage at the thigh level, and on 15 with deficits after total hip arthroplasty. Results were analyzed by the procedure performed and by the outcome in both the peroneal and tibial divisions.

CONCLUSION: Protein Tyrosine Kinase inhibitor Patients with mild or no motor deficits and those with pain that was manageable did not undergo surgery and were treated conservatively. For patients with significant motor deficits and those with pain that was not responsive to pharmacological management, physical and occupational therapy required surgical intervention. Patients who had positive nerve action potentials required neurolysis only and

had the best recovery, whereas those with negative nerve action potentials required more extensive intervention entailing reanastomosis or grafting and had worse outcome. In general, the outcome was better for the tibial than for the peroneal divisions, regardless of the type of BCKDHA intervention.”
“Physical injury or compression of the root, dorsal root ganglion, or peripheral sensory axon leads to well-defined changes in biology and function. Behaviorally, humans report ongoing

painful dysesthesias and aberrations in function, such that an otherwise innocuous stimulus will yield a pain report. These behavioral reports are believed to reflect the underlying changes in nerve function after injury, wherein increased spontaneous activity arises from the neuroma and dorsal root ganglion and spinal changes increase the response of spinal projection neurons. These pain states are distinct from those associated with tissue injury and pose particular problems in management. To provide for developing an understanding of the underlying mechanisms of these pain states and to promote development of therapeutic agents, preclinical models involving section, compression, and constriction of the peripheral nerve or compression of the dorsal root ganglion have been developed. These models give rise to behaviors, which parallel those observed in the human after nerve injury. The present review considers these models and their application.

(C) 2012 Elsevier Ltd All rights reserved “
“Rationale Tram

(C) 2012 Elsevier Ltd. All rights reserved.”
“Rationale Tramadol is a centrally acting clinically

effective analgesic, with a weak opioid receptor affinity. It shows antidepressant-like effects in animal models such as forced swimming test, learned helplessness, and unpredictable chronic mild stress (UCMS) and enhances the concentrations of noradrenaline (NA) and serotonin (5-HT) by interfering with their reuptake and release mechanisms, like some antidepressants.

Objectives The aim of this study was to explore whether the antidepressant-like effects of tramadol is affected LXH254 in vitro by the serotonergic system. For this purpose, the effects of a lesion of the dorsal raphe nucleus (DRN) by 5,7-dihydroxytryptamine (5,7-DHT) on the action of tramadol (20 mg/kg, i.p.) on depression-related behavior and neurochemical correlates were investigated in mice. From the third week onward, we administered tramadol chronically during 4 weeks.

Results Tramadol reversed the physical and behavioral abnormalities induced by the UCMS. Furthermore, the lesion of the DRN by 5,7-DHT antagonized the antidepressant-like effects of tramadol

on the coat click here state, in the splash test but not in the resident-intruder test. The results obtained by high-pressure liquid chromatography showed that the level of 5-HT was reduced by the lesion in some brain regions without affecting the level of NA. Moreover, while the UCMS regimen diminished the level of 5-HT, tramadol increased the level of this neurotransmitter in certain regions.

Conclusions These results seem to indicate Astemizole that the serotonergic system is critically involved in the antidepressant-like effects of tramadol in the UCMS in mice.”
“D-Amino acid oxidase (DAAO) is a well-known flavoenzyme that catalyzes the oxygen-dependent oxidative de-amination of amino acid D-isomers with absolute stereospecificity, which results in a-keto acids, ammonia and hydrogen peroxide. Recently, the extraordinary functional plasticity of DAAO has become evident; in turn, boosting research on this flavoprotein. Protein engineering has allowed for a redesign of DAAO substrate specificity, oxygen

affinity, cofactor binding, stability, and oligomeric state. We review recent developments in utilizing DAAO, including as a biocatalyst for resolving racemic amino acid mixtures, as a tool for biosensing, and as a new mechanism of herbicide resistance. Perspectives for future biotechnological applications of this oxidative biocatalyst are also outlined.”
“Influenza viruses are known for their ability to change their antigenic structure and create new viral strains. Hemagglutinin (HA), for which 16 subtypes have been identified, is a major antigenic determinant essential for the pathogenesis of influenza A viruses. To predict and monitor future epidemics, it is critical to produce various HA subtype antigens conveniently and rapidly.

Seminal findings have been uncovered in both mammalian and non-ma

Seminal findings have been uncovered in both mammalian and non-mammalian model in large result of the extraordinary conservation of both genetic elements and differentiation processes between mammals and non-mammalians. Emerging model organisms, such as the nematode and zebrafish have made it possible to assess the effects of small molecules rapidly, inexpensively, and on a miniaturized scale. By combining the scale and throughput of in vitro screens with the physiological TPCA-1 complexity and traditional animal studies, these models are providing relevant information on molecular events in the etiology of neurodegenerative disorders. The utility of these models is largely driven by the functional

conservation seen between them and higher organisms, including humans so that knowledge obtained using non-mammalian model systems can often provide a better understanding of equivalent processes, pathways, and mechanisms in man. Understanding the molecular events that trigger neurodegeneration has also greatly relied upon the use of tissue culture models.

The purpose of this summary is to provide-state-of-the-art review of recent developments of non-mammalian experimental models and their utility in addressing issues pertinent to neurotoxicity (Caenorhabditis elegans and Danio rerio). The synopses by Aschner and Levin summarize how

genetic mutants of these species can be used Epigenetics inhibitor to complement the understanding of molecular and cellular mechanisms associated with neurobehavioral toxicity and neurodegeneration. Next, studies by Sunol and Olopade detail the predictive value of cultures in assessing neurotoxicity. Sunol and colleagues summarize present novel information strategies

based on in vitro toxicity assays that are predictive of cellular effects that can be extrapolated to effects on individuals. Olopade and colleagues describe cellular changes caused by sodium metavanadate (SMV) and demonstrate how rat primary astrocyte cultures can be used as predicitive tools to assess the neuroprotective effects of antidotes on vanadium-induced astrogliosis and demyelination. (C) 2010 Elsevier Inc. All rights reserved.”
“Heat shock protein 90 (Hsp90) is a molecular chaperone with many oncogenic client proteins. The small-molecule Hsp90 inhibitor alvespimycin, a geldanamycin Casein kinase 1 derivative, is being developed for various malignancies. This phase 1 study examined the maximum-tolerated dose (MTD), safety and pharmacokinetic/pharmacodynamic profiles of alvespimycin in patients with advanced acute myeloid leukemia (AML). Patients with advanced AML received escalating doses of intravenous alvespimycin (8-32mg/m(2)), twice weekly, for 2 of 3 weeks. Dose-limiting toxicities (DLTs) were assessed during cycle 1. A total of 24 enrolled patients were evaluable for toxicity. Alvespimycin was well tolerated; the MTD was 24 mg/m(2) twice weekly.

However, our initial study revealed that intrathecal lipopolysacc

However, our initial study revealed that intrathecal lipopolysaccharide failed to induce low-threshold mechanical allodynia in naive rats, suggestive that TLR4 agonism may be insufficient to enhance pain. These studies explore the possibility that a second signal is required; namely, heat shock protein-90 (HSP90). This candidate was chosen for study given its known importance as a regulator of TLR4 signaling. A combination of in vitro TLR4 cell signaling Blasticidin S purchase and in vivo behavioral studies of pain modulation suggest

that TLR4-enhancement of neuropathic pain and TLR4-suppression of morphine analgesia each likely require HSP90 as a cofactor for the effects observed. In vitro studies revealed that dimethyl sulfoxide (DMSO) enhances HSP90 release, suggestive that this may be a means by which

DMSO enhances TLR4 signaling. While 2 and 100 mu g lipopolysaccharide intrathecally did not induce mechanical allodynia across the time course tested, co-administration of 1 mu g lipopolysaccharide with a drug that enhances HSP90-mediated TLR4 signaling now induced robust allodynia. In support of this allodynia being mediated via a TLR4/HSP90 pathway, it was prevented or reversed by intrathecal co-administration of a HSP90 inhibitor, a TLR4 inhibitor, a microglia/monocyte GDC-0068 research buy activation inhibitor (as monocyte-derived cells are the predominant cell type expressing TLR4), and interleukin-1 receptor antagonist (as this proinflammatory cytokine is a downstream consequence of TLR4 activation). Together, these results suggest for the first time that TLR4 activation is necessary but not sufficient to induce spinally mediated pain enhancement. Rather, the data suggest that TLR4-dependent pain phenomena may require contributions by multiple components of the TLR4 receptor complex. (C) 2009 IBRO. Published by Elsevier Ltd. All rights reserved.”
“IgA nephropathy is the most common glomerular disease worldwide, yet there is Lck no international consensus for its pathological or clinical classification. Here a new classification for IgA nephropathy is presented

by an international consensus working group. The goal of this new system was to identify specific pathological features that more accurately predict risk of progression of renal disease in IgA nephropathy, thus enabling both clinicians and pathologists to improve individual patient prognostication. In a retrospective analysis, sequential clinical data were obtained on 265 adults and children with IgA nephropathy who were followed for a median of 5 years. Renal biopsies from all patients were scored by pathologists blinded to the clinical data for pathological variables identified as reproducible by an iterative process. Four of these variables: (1) the mesangial hypercellularity score, (2) segmental glomerulosclerosis, (3) endocapillary hypercellularity, and (4) tubular atrophy/interstitial fibrosis were subsequently shown to have independent value in predicting renal outcome.

cereus biocontrol agents In previous work, we isolated the bacte

cereus biocontrol agents. In previous work, we isolated the bacteriophage Sotrastaurin nmr B4 (accession

no. JN790865), which is a lytic phage infecting B. cereus, from forest mud, and its genome was sequenced and analyzed to annotate important features (Shin et al., unpublished). In the present study, an endolysin gene was identified in the B4 bacteriophage genome. This endolysin gene was cloned and expressed in Escherichia coli, and the purified endolysin was characterized for its biochemical properties. To the best of our knowledge, LysB4 is the first endolysin belonging to the L-alanoyl-D-glutamate endopeptidases originating from B. cereus bacteriophages. Results Identification and expression of the LysB4 phage endolysin Annotation of bacteriophage B4 genome sequence identified a predicted open reading frame (ORF) for a putative endolysin gene (Shin et al., unpublished). This

789-bp-long ORF was designated lysB4. Using the InterProScan program (http://​www.​ebi.​ac.​uk/​Tools/​pfa/​iprscan/​), LysB4 was predicted check details to have the VanY domain (PF02557) at the N terminus and SH3_5 domain (PF08460) at the C terminus (Figure 1a). According to BLASTP analysis [20], the N terminus of LysB4 had high similarity to L-alanoyl-D-glutamate peptidases of Listeria monocytogenes FSL J1-175 (ZP 05387674), Bacillus FAK inhibitor subtilis subsp. subtilis str. 168 (CwlK, NP 388163), the Listeria phage A500 (Ply500, YP 001488411) and the Bacillus phage SPO1 (YP 001487954), and the C terminus had high similarity to proteins belonging to B. cereus AH676 (ZP 0419059), Bacillus phages TP21-L (Ply21, CAA72267) and bg1 (LysBG1, ABX56141), and the Lactobacillus phage LL-Ku (AAV30211). Among these proteins, Ply500 of Listeria phage A500 needs Zn2+ in its active site according to a structural analysis [21]. The three Zn2+-coordinating residues (His80, Asp87 and His133) characterized in PlyA500 were conserved in the amino acid sequence of LysB4

[21], and the Zn2+ binding domain (SxHxxGxAxD) reported in Enterococcus VanX was found in LysB4 (Figure 1b) [22]. Figure 1 Sequence analysis of LysB4. (a) Domain structures of LysB4 compared with four other peptidoglycan hydrolases. CwlK, the cell wall hydrolase in B. subtilis (ZP 08507241); Liothyronine Sodium Ply500, an endolysin in a L. monocytogenes phage (CAA59365); Ply21, an endolysin in a B. cereus phage (CAA72267); and LysBG1, an endolysin from a Bacillus phage (ABX56141). The grey shadows indicate conserved regions between proteins. (b) Alignment of amino acid sequences of LysB4, Ply500 and CwlK in their VanY domains. Three small triangles indicate Zn2+ binding residues, and the zinc binding motif was boxed. Recombinant LysB4 was cloned and expressed in E. coli with an N-terminal His-tag followed by purification using affinity chromatography. SDS-PAGE showed a single band between 26 and 34 kDa, which was consistent with the calculated molecular mass (28 kDa; Figure 2a).

Pritzlaff CA, Chang JC, Kuo SP, Tamura GS, Rubens CE, Nizet V: Ge

Pritzlaff CA, Chang JC, Kuo SP, Tamura GS, Rubens CE, Nizet V: Genetic basis for the beta-haemolytic/cytolytic activity of group B Streptococcus . Mol Microbiol 2001, 39:236–247.PubMedCrossRef 28. Doran KS, Chang JC, Benoit VM, Eckmann L, Nizet V: Group B streptococcal beta-hemolysin/cytolysin buy CH5424802 promotes invasion of human lung epithelial cells and the release of interleukin-8.

J Infect Dis 2002, 185:196–203.PubMedCrossRef 29. Liu GY, Doran KS, Lawrence T, Turkson N, Puliti M, Tissi L, Nizet V: Sword and shield: linked group B streptococcal beta-hemolysin/cytolysin and carotenoid pigment function to subvert host phagocyte defense. Proc Natl Acad Sci U S A 2004, 101:14491–14496.PubMedCentralPubMedCrossRef 30. Baker JR, Pritchard DG: Action pattern and substrate specificity of the hyaluronan lyase from group B streptococci. Biochem J 2000,348(Pt 2):465–471.PubMedCrossRef 31.

Benchetrit LC, Fracalanzza SE, Peregrino H, Camelo AA, Sanches LA: Carriage of Streptococcus Ispinesib cost agalactiae in women and neonates and distribution of serological types: a study in Brazil. J Clin Microbiol 1982, 15:787–790.PubMedCentralPubMed 32. Haguenoer E, Baty G, Pourcel C, Lartigue MF, Domelier AS, Rosenau A, Quentin R, Mereghetti L, Lanotte P: A multi SGC-CBP30 manufacturer locus variable number of tandem repeat analysis (MLVA) scheme for Streptococcus agalactiae genotyping. BMC Microbiol 2011, 11:171.PubMedCentralPubMedCrossRef 33. Radtke A, Lindstedt BA, Afset JE, Bergh K: Rapid multiple- locus variant-repeat assay (MLVA) for genotyping of Streptococcus agalactiae . J Clin Microbiol 2010, 48:2502–2508.PubMedCentralPubMedCrossRef 34. Uh Y, Kim HY, Jang IH, Hwang GY, Yoon KJ: Correlation of serotypes and genotypes of macrolide-resistant Streptococcus agalactiae . Yonsei Med J 2005, 46:480–483.PubMedCentralPubMedCrossRef 35. Rosini R, Rinaudo CD, Soriani M, Lauer P, Mora M, Maione D, Taddei A, Santi I, Ghezzo C, Brettoni

C, et al.: Identification of novel genomic islands coding for antigenic pilus -like ADAMTS5 structures in Streptococcus agalactiae . Mol Microbiol 2006, 61:126–141.PubMedCrossRef 36. Martins ER, Andreu A, Melo-Cristino J, Ramirez M: Distribution of Pilus islands in streptococcus agalactiae that cause human infections: Insights into evolution and implication for vaccine development. Clin Vaccine Immunol 2013, 20:313–316.PubMedCentralPubMedCrossRef 37. Forquin MP, Tazi A, Rosa-Fraile M, Poyart C, Trieu-Cuot P, Dramsi S: The putative glycosyltransferase-encoding gene cylJ and the group B Streptococcus (GBS)-specific gene cylK modulate hemolysin production and virulence of GBS. Infect Immun 2007, 75:2063–2066.PubMedCentralPubMedCrossRef 38. Merritt K, Jacobs NJ: Characterization and incidence of pigment production by human clinical group B streptococci. J Clin Microbiol 1978, 8:105–107.PubMedCentralPubMed 39. Milligan TW, Baker CJ, Straus DC, Mattingly SJ: Association of elevated levels of extracellular neuraminidase with clinical isolates of type III group B streptococci.

In addition to serum calcium regulation and stimulation of bone r

In addition to serum calcium regulation and stimulation of bone resorption [4], parathyroid hormone (PTH) is known to stimulate bone formation under certain conditions [5]. It is also known that PTH can cause bone resorption and is thus associated with both anabolic and catabolic activities [6–10]. The possibility that PTH has paradoxical effects on bone was first proposed by Selye in 1932 after he observed that continuous infusion in vivo of crude preparations

find more of PTH-elevated bone formation and also dominantly bone resorption, while intermittent administration of the hormone resulted mainly in a stimulation of bone formation especially at the trabecular surface. Later studies have emphasized the importance of evaluating the effects of PTH not only in the trabecular region but also in cortical areas. The ovariectomized (OVX) rat serves as a validated experimental model of post-menopausal osteoporosis. Animals develop substantial osteoporosis within a few months after ovariectomy [11]. The proximal metaphysis of the tibia and lumbar vertebrae are suitable common sites used to investigate bone histomorphometric and mechanical changes in this rodent osteoporosis model. These regions, however, have a high content of trabecular bone, but a very thin cortical shell [12,

13]. Next to the femoral neck fracture, the trochanteric selleckchem fracture is one of the most common fracture types of the proximal femur in human, especially in patients with progressive osteoporosis. This part new of the femur contains

check details both trabecular and cortical bone, in contrast to the femoral shaft. The trochanteric part of femur therefore seems to be a further and additional important area to investigate the biomechanical changes induced after treatment with antiosteoporosis drugs such as parathyroid hormone, which appear to rapidly influence both cortical and trabecular bone formation. The known sufficient and thick muscle insertions (cuff) in this region make this skeletal site also interesting for evaluating the effect of mechanical stimulations like whole body vibrations (like high-frequency, low-magnitude mechanical stimulations). To the best of our knowledge, there are no published studies that have used mechanical tests to characterize the trochanteric region of the femur to date, presumably because of the many problems encountered in designing a reproducible bending and breaking test in this location. The most conventional methods for evaluating rat hip failure are based on axial compression approaches [14]. However, as most osteoporotic hip fractures result from lateral falls, it is necessary to establish additional mechanical testing methods that more closely resemble clinical conditions (lateral loading). It is also necessary to study the effects of antiosteoporosis drugs in skeletal sites that exhibit both sizeable trabecular and cortical areas with an intact periost covering.

J Hypertens 2007;25:1751–62 PubMedCrossRef

2 Mancia G,

J Hypertens. 2007;25:1751–62.PubMedCrossRef

2. Mancia G, Fagard R, Narkiewicz K, Redon J, Zanchetti A, Bohm M, et al. 2013 ESH/ESC guidelines for the management of arterial hypertension: the Task Force for the Management of Arterial Hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC). Eur Heart J. 2013;34:2159–219.PubMedCrossRef 3. James PA, Oparil S, Carter BL, Cushman WC, Dennison-Himmelfarb C, Handler J, et al. Evidence-based guideline for the management of high blood pressure in adults: report from the panel members appointed to the Eighth Joint National Androgen Receptor antagonist Committee (JNC 8). JAMA. 2014;311:507–20. 4. Weber MA, Schiffrin EL, White WB, Mann S, Lindholm LH, Kenerson JG, et al. Clinical practice guidelines for the management of hypertension in the community: a statement by the American

Society of Hypertension and the International Society of Hypertension. J Hypertension. 2014;32:3–15. selleck 5. Effects of calcium antagonists on the risks of coronary heart disease, cancer and bleeding. Ad Hoc Subcommittee of the Liaison Committee of the World Health Organisation and the International Society of Hypertension. J Hum Hypertens. 1997;11:331–2. 6. Law MR, Morris JK, Wald NJ. Use of blood pressure lowering drugs in the prevention of cardiovascular disease: meta-analysis of 147 randomised trials in the context of expectations from prospective epidemiological studies. BMJ. 2009;338:b1665.PubMedCentralPubMedCrossRef 7. Turnbull F, Neal B, Algert C, Chalmers J, Chapman N, Cutler J, et al. Effects of different blood pressure-lowering regimens on PF-04929113 datasheet major cardiovascular events in individuals with and without diabetes mellitus: results of prospectively designed overviews of randomized trials. Arch Intern Med. 2005;165:1410–9.PubMedCrossRef 8. Verdecchia P, Reboldi G, Angeli F, Gattobigio

R, Bentivoglio M, Thijs L, et al. Angiotensin-converting second enzyme inhibitors and calcium channel blockers for coronary heart disease and stroke prevention. Hypertension. 2005;46:386–92.PubMedCrossRef 9. Turnbull F. Effects of different blood-pressure-lowering regimens on major cardiovascular events: results of prospectively-designed overviews of randomised trials. Lancet. 2003;362:1527–35.PubMedCrossRef 10. Arima H, Murakami Y, Lam TH, Kim HC, Ueshima H, Woo J, et al. Effects of pre hypertension and hypertension subtype on cardiovascular disease in the Asia-Pacific region. Hypertension. 2012;59:1118–23.PubMedCrossRef 11. He FJ, MacGregor GA. Cost of poor blood pressure control in the UK: 62 000 unnecessary deaths per year. J Hum Hypertens. 2003;17:455–7.PubMedCrossRef 12. Zanchetti A, Grassi G, Mancia G. When should antihypertensive drug treatment be initiated and to what levels should systolic blood pressure be lowered? A critical reappraisal. J Hypertens. 2009;27:923–34.PubMedCrossRef 13.

The light-dependent Chl a fluorescence yield is variable between

The light-dependent Chl a fluorescence yield is variable between a lowest, intrinsic level F o (the “O” level) at full JQ1 mw photochemical quenching under dark-adapted conditions and a highest level F m (the “P” level) at saturating light intensities at which all quenching is released. Variable GSK872 concentration fluorescence is defined as F v = F m − F o. The primary quinone acceptor of PS II, QA, has since long been known as the major and principal

quencher; the quenching is released upon its photoreduction (Duysens and Sweers 1963). F m is associated with full reduction of QA and with an electron trapping-incompetent closed RC. The multiphasic recovery kinetics of variable fluorescence after single turnover excitation (STF) has been discussed to point to an energy-linked heterogeneity of RCs and primary processes occurring therein. Kinetic studies have provided evidence for a photochemical role and hitherto unrecognized properties of QB-nonreducing RCs in PS II electron transport (Vredenberg et al. 2006, 2007; Vredenberg 2008; van Rensen and Vredenberg 2009). These data have shown, in contrast to what commonly has been assumed about a photochemical inactivity 17DMAG of QB-nonreducing

RCs in PS II electron transport (Melis 1985; Chylla et al. 1987; Lavergne and Leci 1993), that these centers are able to reduce QB after a second hit. The fact that reduced QB-nonreducing RCs (with QA −) are electron trapping-competent, giving rise to a dark reversible variable fluorescence, has provided evidence that the double-reduced acceptor pair [PheQA]2− in these RCs can reduce QB (Vredenberg et al. 2009). Quantitative analysis of induction kinetics of variable chlorophyll a fluorescence in intact plant leaves upon 2 s pulses, like we have used here, has enabled the development of a descriptive fluorescence induction algorithm

(FIA) (Vredenberg 2008; Vredenberg and Prasil 2009). Briefly, solutions of the differential equations dictated by the electron transfer reaction patterns have D-malate dehydrogenase provided the mathematical elements of the algorithm with which the kinetics of primary photochemical reactions of PSII can be described quantitatively in terms of their driving forces, rate constants, and transport conductances. The application of the fluorescence induction algorithm (FIA) has provided evidence that the initial events of energy trapping in PSII are accompanied by (i) the release of primary photochemical quenching in a heterogeneous system of QB-reducing and QB-nonreducing RCs during the OJ phase, (ii) the release of photoelectrochemical quenching associated with ΔμH-controlled accumulation and subsequent double reduction of QB-nonreducing RCs during the JI phase, and (iii) a stimulation of variable fluorescence during the IP-phase by the trans-thylakoid electric potential generated by the CET (PSI) driven proton pump.