Authors’ VX-680 contributions KZ participated in the collection of clinical data, performed patient follow-ups, and drafted the manuscript. CT made substantial contributions to conception and design of this research and has reviewed the manuscript for important intellectual content and given final approval of the version to be published. HD assisted during patient follow-ups and collection of data. ZX participated in project coordination and assisted with

manuscript. Each author has participated sufficiently in this work to take public responsibility for the appropriate portions of the manuscript. All authors read and approve of the final manuscript.”
“Backgrounds Nasopharyngeal cancer (NPC), a fast-growing tumour, characterized by a high frequency of nodal and distant

metastasis at diagnosis, Smad2 phosphorylation is rare in many areas of the world but common in Southeast Asia [1]. Evidence suggests that Epstein-Barr virus (EBV) infection is a major risk factor contributing to its tumorigenesis [2]. Besides, cigarette Erismodegib molecular weight smoking and alcohol consumption are probably important etiological factors increasing the risk of developing NPC [3]. Moreover, environmental chemical pollutions, widely spread carcinogens, are difficult to be degraded in the environment and thus may have a long-term effect on human health. Despite many individuals exposed to EBV infection, environmental risk factors and/or with ADP ribosylation factor extensive tobacco and alcohol consumption, NPC develops only in a small group of exposed people, which suggests that genetic host factors might contribute to the carcinogenic mechanisms. Recent evidence indicates that carcinogen-metabolizing genes and DNA-repair genes may play critical roles in determining individual susceptibility to cancers. Polymorphisms in these genes encoding the enzymes, possibly by altering their expression and function, may increase or decrease carcinogen activation/detoxication and modulate DNA repair. Xenobiotics can be detoxified by phase II enzymes, such

as GSTM1 and GSTT1 which have been suggested to be involved in detoxification of polycyclic aromatic hydrocarbons (PAHs) and benzo(a)pyrene [4]. Evidence suggests that genetic polymorphisms of these genes might increase individual susceptibility to NPC. Therefore, a number of published studies have focused on GSTM1 and GSTT1 genetic variation with respect to NPC and have yielded conflicting results. Whether GSTM1 or GSTT1 polymorphism is a risk factor for NPC remains largely uncertain. Since a single study may have been underpowered to clarify the associations of GSTM1 or GSTT1 polymorphisms with NPC susceptibility, in the present study we aimed to perform evidence-based quantitative meta-analyses that might increase statistical power to address this controversy.

Several factors influence

participation, including perceptions about cancer risk and survivability, lack of awareness about the role of genetic testing, and concern about how to emotionally deal with genetic risk TH-302 in vivo feedback. Concerns about being unable to “handle” testing learn more and results, and feeling overwhelmed by anxiety, cited by women in particular. Thompson, Valdimarsdottir, Duteau-Buck et al. (2002) 76 (100 %) At least one FDR with breast and/or ovarian cancer; no personal cancer history Investigated predictors for genetic counseling and testing for breast cancer susceptibility. Participants completed a questionnaire, and underwent genetic counseling and genetic testing. Knowledge of breast cancer, breast cancer-specific emotional distress, perceived benefits and barriers of genetic counseling and testing. Women declining genetic counseling or testing were less knowledgeable about breast cancer genetics than women receiving genetic counseling and testing. Thompson, Valdimarsdottir, Jandorf et al. (2003) 273 (42 %; 115) No criteria specified Interviews explored genetic testing attitudes, and determined the extent to which ethnicity, awareness of genetic testing, and

medical mistrust is associated with genetic testing attitudes. Ethnicity, knowledge of genetic testing, medical mistrust, risks and benefits of genetic testing AfAm women strongly concurred more with concerns about perceived disadvantages (confidentiality and effects on family) and testing

this website abuses (religion), compared with Caucasian women. RCT Randomized Controlled Trial, AfAm African American, FDR First-degree relative Overall, 10 studies included only African Americans in the sample (Matthews et al. 2000; Halbert et al. 2005a, b, 2006, 2010; Hughes et al. 2003; Thompson et al. 2002; Lipkus et al. 1999; Kessler et al. 2005; Charles et al. 2006). Of these, nine included only African American women; one included both men and women in the study sample (Matthews et al. 2000). Fifteen studies included African American women who were at risk for developing breast PAK6 and/or ovarian cancer; the remaining three included a combined sample of at-risk and not at-risk participants. Most studies (N = 14) evaluated predictors, or the process, of participation in genetic susceptibility counseling or testing; far fewer studies (N = 4) examined the outcome of testing, counseling, or program participation (Halbert et al. 2010; Lerman et al. 1999; Charles et al. 2006; Ford et al. 2007). Uptake of genetic testing and/or counseling was reported by eight studies (Charles et al. 2006; Halbert et al. 2005b, 2006, 2010; Hughes et al. 2003; Thompson et al. 2002; Armstrong et al. 2005; Ford et al. 2007). The proportion of women who elected to receive their results varied considerably, with rates ranging from 25 % (Halbert et al. 2006) to 61 % (Hughes et al.

Details of the synthesis procedure have been presented in a previous study [31]. A solution of AgNO3 (1 mM) in 250-mL ultrapure water was heated to 80°C. A volume of 10-mL aqueous solution of Na3C6H5O7 · 2H2O (0.34 mM) was then added to the AgNO3 solution. Heating was continued to 90°C for 30 min after adding the citrate solution. www.selleckchem.com/products/azd4547.html The color of the solution changed from the colorless water to yellow after 15 min of heating and to gray after 25 min. The resulting sol is simply

silver nanoparticles coated with organic shell, dispersed in water at a concentration of 1 mM [32, 33]. Preparation of silver nanoparticle solution with different concentrations The different concentrations of the silver nanoparticle solution were

fabricated by increasing the concentration of the silver nanoparticle solution from 1 mM to 0.1 M by centrifugation. Centrifugation was conducted at 9,000 revolutions per minute (rpm) for 5 min in 10-mL centrifuge tubes. The water was extracted from the centrifuge tubes using a pipette, leaving aqueous-based Ag nanoparticle paste at the bottom. Shock the tube to make the nanoparticle paste back into suspension, then collect the Caspase pathway rest of the solution for the next centrifugation. Repeat this process until the required concentration solution was obtained. Preparation of silver nanoparticle films on silica substrates Silicon wafers with single side polished were cut into required size, depending on the demand. The prepared silicon wafers were cleaned by an ultrasonic cleaning machine using deionized water for 10 min. These silicon wafers were then laid in a container, and the container was placed on an inclined platform with the angle of inclination α = 10°. The schematic of this device is shown in Figure 1. The solution of silver nanoparticles prepared with different concentrations was poured into

the container. The evaporation was carried out inside an oven. This oven temperature was set to 50°C. After evaporation of the solvent, the self-assembled silver nanoparticle film was obtained. Figure 1 Schematic illustration of silver nanoparticles self-assembled CDK inhibitor on silica substrate (a, b). PD0332991 chemical structure Characterization techniques The absorption spectrum of the silver colloid was obtained using a UV-vis (UV-9000S, Shanghai Metash Instruments Co., Ltd., China) spectrophotometer. The morphology of the silver nanoparticles was examined by transmission electron microscopy (TEM; JEM-2010, JEOL Ltd., Akishima, Tokyo, Japan). The silver nanoparticle films were imaged using a scanning electron microscope (SEM; XL30 S-FEG, FEI Co., Hillsboro, OR, USA). The cross-sectional profiles of the silver nanoparticle films were measured using an atomic force microscope (AFM; Pico Scan TM 2500, Scientec, Les Ulis, France) and a Veeco surface profiler (Wyko NT1100, Veeco Instruments Inc., Plainview, NY, USA).

The cluster encoding lysis related proteins (ORF13 to ORF16) and the phage tail fiber protein (ORF21) shared lower degrees of identity, while ORF22 (hypothetical protein) shared no appreciable homology. The very recently reported P2-like phage remnant in S. maltophilia strain P28 possesses 23 orfs [11], nine of the deduced proteins share 31% to 53% identities with the Smp131 encoded proteins (Additional file 6: Table S3). Smp131 late genes may be regulated in a manner similar to that in P2 P2 has four late promoters, PP, PO, PV, and PF, possessing the consensus sequence TGT-N12-ACA and

controlling PQ, ONMLKRS, VWJIHG, and F I F II EE’TUD operons, respectively [36, 37]. Transcription of these operons depends on the Ogr protein, a zinc-finger containing transcriptional activator with a conserved RAD001 cysteine

motif, CX2CX22CX4C, where a zinc atom coordinates with four cysteine residues [38, 39]. In Smp131, four putative late promoters were observed with sequences similar to TGT-N12-ACA, which were designated as PP’, PO’, PJ’, and PV’ located at nt 4398–4381, 4381–4398, 10,964-10,981, and 14,928-14,946 in the genome, respectively (Figure 3). Operons presumably controlled by PP’ and PO’ were analogous to those by P2 PP and PO, respectively, but those by PJ’ and PV’ had some exchanged members due to gene rearrangement, that is, VWJIHG and F I F II EE’TUD in P2 versus orf19-orf22 (homologous to JIHG) and orf23-orf32 in Smp131 (Figure 3). Additionally, the protein encoded by Smp131 orf34, which had a relative position 7-Cl-O-Nec1 purchase similar to that of the P2 Ogr gene, had a conserved CX2CX22CX4C motif, although overall similarity shared by the two proteins was low. Thus, similarity in genome organization, promoter

sequence, and a regulatory protein suggests that Smp131 late genes are regulated in a manner similar to that in P2. tRNA genes are the selleck chemicals preferred sites for integration of P2-like prophages of Xanthomonas and Stenotrophomonas It is known that in E. coli i) P2 can integrate at over 10 different loci, with locI (attB site containing the core sequence, 5′-AAAAAATAAGCCCGTGTAAGGGAGATT-3′, which is identical to the attP sequence) being preferred over any other sites in E. coli C, ii) this Niclosamide site is occupied by a remnant of a P2 prophage in E. coli K-12 and P2 therefore will integrate into secondary sites, and iii) the P2 integrase accepts at least up to 37% mismatches within the core sequence [40]. Searching for a region similar to the P2 attP site in Smp131 genome revealed no such region. We then turned to identify putative attR and attL at the ends of prophage sequences from Stenotrophomonas and Xanthomonas and observed a 46-nucleotide perfect direct repeat at the extremities of the integrated prophage of S.

The differences

for the RGFP966 mouse femoral neck BMDs were much greater than for the femur total BMDs −0.164 ± 0.043 g/cm2 (21.0%, P < 0.001) and −0.156 ± 0.038 g/cm2 (20.0%, P < 0.001) for left and right, respectively. Table 1 Demographics of the participants   Mean ± SD Facility 1 Facility 2 Facility 3 Pooled N 28 29 30 87 Age (years) 63.4 ± 9.2 64.1 ± 9.4 62.3 ± 9.3 63.0 ± 9.1 Vactosertib Height (cm) 160.9 ± 7.2 160.5 ± 7.5 159.6 ± 8.3 160.3 ± 7.5 Weight (kg) 64.0 ± 10.6 65.0 ± 16.1 68.0 ± 18.5 64.0 ± 15.3 Hologic BMD  L1-L4 spine 0.930 ± 0.151 0.938 ± 0.184 0.952 ± 0.159 0.941 ± 0.159  L2-L4 spine 0.946 ± 0.162 0.989 ± 0.151

0.970 ± 0.166 0.970 ± 0.160  Left total hip 0.819 ± 0.143 0.856 ± 0.099 0.845 ± 0.127 0.841 ± 0.124  Right total hip 0.815 ± 0.149 0.854 ± 0.104 0.839 ± 0.116 0.837 ± 0.124  Left neck 0.690 ± 0.124 0.713 ± 0.091 0.714 ± 0.109 0.706 ± 0.108  Right neck 0.699 ± 0.132 0.718 ± 0.081 0.715 ± 0.109 0.711 ± 0.108 GE-Lunar BMD  L1-L4 spine 1.102 ± 0.181 1.112 ± 0.171 1.114 ± 0.189 1.110 ± 0.180  L2-L4 spine 1.120 ± 0.192 1.139 ± 0.180 1.136 ± 0.198 1.132 ± 0.190  Left total hip 0.886 ± 0.153 0.946 ± 0.108 0.902 ± 0.125 0.912 ± 0.131  Right total hip

0.879 ± 0.159 0.935 ± 0.110 0.899 ± 0.116 0.905 ± 0.132  Left neck 0.847 ± 0.139 0.900 ± 0.090 0.861 ± 0.119 0.870 ± 0.119  Right neck 0.854 ± 0.150 0.891 ± 0.079 www.selleckchem.com/products/PLX-4720.html 0.855 ± 0.117 0.867 ± 0.118 No statistically significant differences (p < 0.05) were found between the sites for the variables we measured Facility 1: New Mexico Clinical Research & Osteoporosis Center, Facility 2: Colorado Center for Bone Research, Facility 3: University of California at San Francisco BMD bone mineral density Table 2 Means and standard deviation of Hologic Apex and GE-Lunar Prodigy BMD in g/cm2 Variables r 2 value BMD results sBMD results Hologic Prodigy Difference Hologic Prodigy Difference L1-L4 spine 0.99 0.941 ± 0.159 1.110 ± 0.180 Liothyronine Sodium −0.169 ± 0.063 (16.5%)** 1.011 ± 0.168 1.053 ± 0.174 −0.042 ± 0.060 (4.1%)** L2-L4 spine 0.98 0.970 ± 0.160 1.132 ± 0.190 −0.164 ± 0.048 (15.6%)** 1.040 ± 0.170 1.075 ± 0.184 −0.035 ± 0.050 (3.3%)** Left total hip 0.95 0.841 ± 0.124 0.912 ± 0.131 −0.072 ± 0.028 (8.2%)** 0.854 ± 0.125 0.862 ± 0.128 −0.009 ± 0.027 (1.0%)* Right total hip 0.96 0.837 ± 0.124 0.905 ± 0.132 −0.068 ± 0.028 (7.8%)** 0.850 ± 0.125 0.855 ± 0.129 −0.005 ± 0.027 (0.5%) Left neck 0.84 0.706 ± 0.108 0.870 ± 0.119 −0.164 ± 0.043 (21.0%)** 0.787 ± 0.117 0.794 ± 0.111 −0.007 ± 0.043 (1.0%) Right neck 0.87 0.711 ± 0.108 0.867 ± 0.118 −0.156 ± 0.038 (20.0%)** 0.792 ± 0.118 0.791 ± 0.111 −0.0006 ± 0.038 (0.6%) *P < 0.05 **P < 0.

The replication locus of the theta-type SCP2 comprises repI and repII genes and an adjacent non-coding sequence to which RepI protein binds [7, 13]. pFP1 and pFP11 contain basic replication loci

of rep and Rabusertib iteron types (direct repeats and/or inverted repeats), to which Rep proteins bind [8]. Conjugal transfer of Streptomyces RC plasmid (e.g. pIJ101) needs a tra gene along with a clt (cis-acting locus of transfer) site [14]. Streptomyces tra genes encode a DNA translocase resembling the chromosomal DNA translocase FtsK of E. coli or SpoIIIE of B. subtilis[3], with double-stranded DNA probably entering the recipient [15]. The TraB of pSVH1 binds to the clt sequence as multimers on the mobilized plasmid and translocates unprocessed DNA at the hyphal tip to a recipient cell [16]. Conjugal transfer of Streptomyces theta-type plasmids (e.g. SCP2 and pZL12) requires a major tra gene and two adjacent genes [17, 18]. In contrast to most bacteria, Streptomyces

species often harbor linear plasmids [19, 20]. Unlike the terminal protein-capped linear replicons of adenoviruses that replicate by a mechanism of strand displacement [21], Streptomyces linear plasmids start replication from a centrally located ori locus [22] and replication BAY 11-7082 concentration proceeds bi-directionally toward the telomeres [23]. At least some Streptomyces linear plasmids (e.g. pSCL1) can propagate in circular mode when the telomeres are deleted [22], while some theta-type circular plasmids (e.g. SCP2 and pFP11) can also propagate in linear mode when the telomeres from a linear plasmid are attached [8]. Results Identification of a

widely distributed Streptomyces species Y27 and its indigenous plasmid pWTY27 among endophytic Streptomyces strains During the course of investigating naturally circular plasmids, we detected 27 plasmids among ~300 newly isolated actinomycete strains from plant samples of Gingko, Taxus and Artemisia annua L in China. Interestingly, 14 of them (Table 1) displayed similar sizes of ca.14-kb DNA bands on agarose gel. These plasmids were PTK6 digested with NcoI and all showed five bands (~8, 2.2, 1.7, 1.3 and 1 kb) on gel electrophoresis (Additional file 1: Figure S1), suggesting that they were an identical plasmid (designated pWTY27). Table 1 Strains and plasmids used in this study Strain and plasmid Genotype or description Source or reference Strains     Streptomyces strains (Y27, Y32, Y33, Y34, Y41, Y42 and G2-1) Isolated from Gingko QNZ harboring pWTY27 This work Streptomyces strains(W15, W24, W37 and W41) Isolated from Artemisia annua L harboring pWTY27 This work Streptomyces strains (Z20, Z54 and Z70) Isolated from Taxus harboring pWTY27 This work S. lividans ZX7 pro-2 str-6 rec-46 dnd SLP2- SLP3- 34 S.

Adjuncts to this approach including

angiography with selective vessel embolization, computed tomography directed drainage of abscess or biloma, and endoscopic retrograde cholangiopancreatography with biliary stenting have recently been integrated into the nonoperative management strategy of liver trauma with encouraging results [13]. Liver packing, although selleck kinase inhibitor a life-saving maneuver is not without complications. Placing sponges between the liver and diaphragm to tamponade bleeding compromises venous return, impairing cardiopulmonary function in patients with already limited reserve. Re-bleeding and intraabdominal abscess formation after pack removal has also been described. In patients who require massive resuscitation, visceral edema and elevated intraabdominal pressures may lead

to subsequent abdominal compartment syndrome with the use of perihepatic packing. Abdominal compartment syndrome may cause compromise of cardiac performance and respiratory function, renal function, splanchnic perfusion, and may impair cerebral perfusion [14–17]. The concepts of damage control laparotomy, multiorgan failure, and abdominal compartment syndrome have lead to the use of temporary MLN2238 ic50 abdominal GS-4997 supplier closures to allow rapid means of abdominal domain control, in anticipation of delayed, definitive intraabdominal injury repair [13, 18, 19]. Vacuum assisted closure (VAC), also referred to as negative pressure wound therapy, has gained wide acceptance for use in the management of a range of acute and chronic wounds as well as for temporary abdominal closures in cases of abdominal compartment syndrome and damage control laparotomy [20, 21]. VAC therapy combines eltoprazine several features conducive to wound healing including apposition, drainage and coverage. VAC has been successfully utilized to treat numerous and varied conditions including decubitus ulcers, skin grafts, enterocutaneous fistulae, animal and insect bites, osteomyelitis, urologic and perineal wounds, burns, and post-sternotomy sternal wound infections

[22–30]. Temporary abdominal closure after damage control laparotomy for abdominal compartment syndrome has been successfully managed using VAC and this modality is now used routinely in our Level I trauma center for such cases. The porcine or swine model has been used extensively to simulate, experimentally, human liver injury [31–38]. A reproducible Grade V liver injury has been consistently attained in a number of swine model liver trauma studies by the standardized use of a device well described in the trauma and military literature [31, 33, 34, 36–38]. Given the complications associated with traditional hepatic packing, the authors present a novel approach to nonresectional therapy in major hepatic trauma utilizing intraabdominal perihepatic vacuum assisted closure or Liver VAC (L-VAC) therapy in the porcine model.

Custom B. melitensis microarrays were utilized to examine the regulons controlled by VjbR and C12-HSL, revealing a large number of genes potentially involved in the virulence and intracellular survival of the organism. Such genes Transmembrane Transporters include adhesins, proteases, lipoproteins, a hemolysin, secretion system components and effector proteins, as well as metabolic genes involved in energy production, amino acid, carbohydrate, and lipid metabolism. Furthermore, deletion of vjbR and C12-HSL treatment altered the expression of genes coding for components involved in the transport of numerous substrates across the cell membrane. The microarray

analyses conducted in this study also confirmed previous findings that fliF and the virB operon are regulated by ΔvjbR and exogenous C12-HSL treatment at an exponential growth phase and stationary growth phase (respectively), as well as the check details potential effector proteins VceA and VceC, validating the microarray approach to identify additional genes regulated by these putative QS components [14, 27]. The contribution of VjbR gene regulation at different growth phases in not fully understood, but microarray analyses suggests

that there are distinct sets of genes regulated at both growth phases in addition to the buy Volasertib flagellar and T4SS operons. Previous studies examining the effect of timing on QS related genes in P. aeruginosa hypothesized that the transcriptional regulator and not the inducing or repressing signal is responsible for the continuum of responses observed [40]. Such tuclazepam a hypothesis is supported by the observed increase of vjbR expression over time in B. melitensis. Deletion of vjbR and treatment of C12-HSL both resulted in a global modulation of gene expression. Examination of the relationship in respect to the genes commonly altered between ΔvjbR and wildtype bacteria administered C12-HSL suggests that C12-HSL reduces VjbR activity, based upon the following observations: 1) An inverse correlation in gene expression for all but three genes found to be altered by VjbR and C12-HSL, 2) Addition of exogenous C12-HSL to growth media mimics the deletion of VjbR

in respect to gene alteration, 3) In the absence of vjbR, C12-HSL treatment has a markedly different effect on gene expression at the stationary growth phase, found to only promote gene expression, and 4) virB repression in response to the addition of C12-HSL is alleviated by deletion of the response receiver domain of VjbR [17]. The observed promotion of gene expression with the treatment of C12-HSL in a ΔvjbR background could potentially be occurring through a second LuxR-like protein BlxR, supported by the high correlation of commonly altered genes by ΔblxR and ΔvjbR with the addition of C12-HSL in independent studies [15, 23]. Often, the LuxR transcriptional regulator and AHL signal form a positive feedback loop, increasing the expression of luxR and the AHL synthesis gene [62].

Conversely, while these pAbs recognized Selleck AZD4547 proteins from diverse subcellular compartments in GS, neither surface proteins nor proteins with a VSP pattern were detected (Figure 1C). Besides the data related to phenotypic

similarities or differences between both assemblages, it has been shown at the molecular level that there are only a few assemblage-specific genes, except for the VSP gene family, where the repertoires of the two isolates are completely different [14]. Therefore, it was not surprising that, after immunization with the WB isolate, we found no VSP labeling in GS trophozoites. The fact that giardins are proteins of check details approximately 30 kDa, and taking into account their high immunoreactivity, prompted us to see more analyze whether the production of mAbs against giardins might have resulted from these infected mice. Thus, after fusion, antibody-producing hybridoma cells were selected by immunofluorescence and dot-blotting assays using WB trophozoites. Several antibodies against the ventral disc and the plasma membrane were produced, with the ones that showed immunoreactivity

in the immunofluorescence and dot-blotting assays being selected for further analysis. Finally, selected hybridomas were grown, screened and cloned. No typical VSP pattern reactivity was found in GS isolates when they were tested using VSP specific mAb (not shown). Thus, the mAbs that recognized VSPs in WB were not investigated any further. Characterization of anti-giardin mAbs Most giardins showed a plasma membrane localization, with some of these being localized in the ventral disc, and the molecular mass of 30 kDa being a feature of all of

them [18, 34–36]. Therefore, we selected the monoclonal antibodies that recognized the plasma membrane or ventral disc but also showed a 30 kDa strip in Western blot assays. Among these, G3G10 and the 12G5 mAbs showed reactivity in both WB and GS trophozoites by Western blot assay (Figure 2). The mobility of the 30 kDa protein on SDS-PAGE was the same under either reducing or non-reducing conditions, indicating that it is a single chain protein with few, if any, intrachain disulfide bonds susceptible to reducing agents (data not shown). Immunoprecipitation assays and peptide mass fingerprinting by MALDI-ToF-MS showed that G3G10 mAb recognized Amino acid α-1 giardin, whereas 12G5 MAb recognized β-giardin in G. lamblia (Table 1). Figure 2 Western blot analysis of WB and GS Giardia proteins recognized by G3G10 (α-1 giardin) and 12G5 (β-giardin) mAbs. Nitrocellulose membranes were incubated with mAbs and developed with peroxidase-coupled anti-mouse Igs. Lane 1: standards of the indicated molecular weight. Table 1 Mass spectrometry data EMPIRIC IN SILICA PROTEIN IDENTITY Acc # Seq. Cov. # pep PI MW PI MW         — 30 5.1 24 Beta-giardin AAU95567 37 9/40 — 35 6.3 34 Alpha-1 giardin PI7063 42 12/54 Differential cellular localization of β-giardin in WB and GS trophozoites In WB trophozoites, β-giardins assemble in 2.

We assign this faster-decaying, shorter-wavelength component with a maximum at 980 nm to Car D2 ∙+ . Although CarD2 has been proposed to be the initial electron donor in the pathway of secondary electron transfer (Lakshmi et al. 2003; Tracewell and Brudvig 2003), the specific spectral perturbations of site-directed mutations near CarD2 on the 980 nm Car∙+ species find more provide the first direct evidence that CarD2 is one of the redox-active Car in PSII. Previous studies have shown that the maximum of the Car∙+ near-IR peak shifts to a slightly shorter wavelength when YD is oxidized to Y D ∙ in all PSII centers (Tracewell

and Brudvig 2003). It Adriamycin mouse was hypothesized that this was either due to an electrochromic shift caused by YD or due to biasing electron transfer so that the redox-active Car closest to Y D ∙ would remain reduced to avoid electrostatic repulsion. However, it has been observed that electrochromic shifts propagate substantial distances through PSII. For example, generating Q A − affects

the visible spectrum of BA, the accessory Chl near PA of P680, from 21 Å away, and also possibly affects the spectrum of BB, 29 Å away (Stewart et al. 2000). check details Although Y D ∙ would most likely have a smaller electrochromic effect than Q A – , its effects do propagate at least as far as P680 (Diner and Rappaport 2002). CarD2 is approximately 25 Å from YD. Alternatively, there are several Car cofactors in CP47 that are at a comparable or even shorter distance from YD; one Car in CP47 is 21 Å from

YD, another is 27 Å away, and two others are about 30 Å from YD. Due to closely spaced distances, an electrochromic shift would not be a definitive indicator of which Car is oxidized, even if it were observable at those distances. It is also possible that oxidation of YD may bias the path of secondary electron transfer. To pull an electron from one of the Car in CP47, two intermediate Chl∙+ would be involved that are each 20 Å from Y D ∙ , to ultimately generate a terminal Car∙+ that may be as close as 21 Å to Y D ∙ . Under these conditions, the 980 nm Car D2 ∙+ may be a more stable radical than the 999 nm Car∙+, resulting in a net shift of the Car∙+ peak to a shorter wavelengths. The near-IR Erastin order spectra of D2-G47W, D2-G47F, and D2-T50F PSII samples contain a relatively larger amount of the Chl∙+ peak as compared to the Car∙+ peak than WT PSII samples (Fig. 4B). One possibility is that the mutations around the headgroup of CarD2 caused a shift of the reduction potential of Car D2 ∙+ to a higher value, making it more difficult to oxidize CarD2 relative to other Chl and Car cofactors. This would destabilize Car D2 ∙+ , which is the predominant donor in the charge separation (980 nm Car∙+, see Fig. 5; Table 1), thus favoring Chl∙+ in a greater portion of PSII centers.