Expanded phenotypic spectrum of neurodevelopmental and neurodegenerative disorder Bryant-Li-Bhoj syndrome with 38 additional individuals.

Bryant-Li-Bhoj syndrome (BLBS), which became OMIM-classified in 2022 (OMIM: 619720, 619721), is caused by germline variants in the two genes that encode histone H3.3 (H3-3A/H3F3A and H3-3B/H3F3B) [1-4]. This syndrome is characterized by developmental delay/intellectual disability, craniofacial anomalies, hyper/hypotonia, and abnormal neuroimaging [1, 5]. BLBS was initially categorized as a progressive neurodegenerative syndrome caused by de novo heterozygous variants in either H3-3A or H3-3B [1-4]. Here, we analyze the data of the 58 previously published individuals along 38 unpublished, unrelated individuals. In this larger cohort of 96 people, we identify causative missense, synonymous, and stop-loss variants. We also expand upon the phenotypic characterization by elaborating on the neurodevelopmental component of BLBS. Notably, phenotypic heterogeneity was present even amongst individuals harboring the same variant. To explore the complex phenotypic variation in this expanded cohort, the relationships between syndromic phenotypes with three variables of interest were interrogated: sex, gene containing the causative variant, and variant location in the H3.3 protein. While specific genotype-phenotype correlations have not been conclusively delineated, the results presented here suggest that the location of the variants within the H3.3 protein and the affected gene (H3-3A or H3-3B) contribute more to the severity of distinct phenotypes than sex. Since these variables do not account for all BLBS phenotypic variability, these findings suggest that additional factors may play a role in modifying the phenotypes of affected individuals. Histones are poised at the interface of genetics and epigenetics, highlighting the potential role for gene-environment interactions and the importance of future research.

Characterization of male breast cancer: results of the EORTC 10085/TBCRC/BIG/NABCG International Male Breast Cancer Program.

Background: Male breast cancer (BC) is rare, managed by extrapolation from female BC. The International Male BC Program aims to better characterize and manage this disease. We report the results of part I, a retrospective joint analysis of cases diagnosed during a 20-year period. Methods: Patients with follow-up and tumor samples, treated between 1990 and 2010, in 93 centers/9 countries. Samples were centrally analyzed in three laboratories (the United Kingdom, the Netherlands and the United States). Results: Of 1822 patients enrolled, 1483 were analyzed; 63.5% were diagnosed between 2001 and 2010, 57 (5.1%) had metastatic disease (M1). Median age at diagnosis: 68.4 years. Of 1054 M0 cases, 56.2% were node-negative (N0) and 48.5% had T1 tumors; 4% had breast conserving surgery (BCS), 18% sentinel lymph-node biopsy; half received adjuvant radiotherapy; 29.8% (neo)adjuvant chemotherapy and 76.8% adjuvant endocrine therapy (ET), mostly tamoxifen (88.4%). Per central pathology, for M0 tumors: 84.8% ductal invasive carcinomas, 51.5% grade 2; 99.3% estrogen receptor (ER)-positive; 81.9% progesterone receptor (PR)-positive; 96.9% androgen receptor (AR)-positive [ER, PR or AR Allred score ≥3]; 61.1% Ki67 expression low (<14% positive cells); using immunohistochemistry (IHC) surrogates, 41.9% were Luminal-A-like, 48.6% Luminal-B-like/HER-2-negative, 8.7% HER-2-positive, 0.3% triple negative. Median follow-up: 8.2 years (0.0-23.8) for all, 7.2 years (0.0-23.2), for M0, 2.6 years (0.0-12.7) for M1 patients. A significant improvement over time was observed in age-corrected BC mortality. BC-specific-mortality was higher for men younger than 50 years. Better overall (OS) and recurrence-free survival (RFS) were observed for highly ER+ (P = 0.001), highly PR+ (P = 0.002), highly AR+ disease (P = 0.019). There was no association between OS/RFS and HER-2 status, Ki67, IHC subtypes nor grade. Conclusions: Male BC is usually ER, PR and AR-positive, Luminal B-like/HER2-negative. Of note, 56% patients had T1 tumors but only 4% had BCS. ER was highly positive in >90% of cases but only 77% received adjuvant ET. ER, PR and AR were associated with OS and RFS, whereas grade, Ki67 and IHC surrogates were not. Significant improvement in survival over time was observed.

Pathologies in Living Kidney Donors Diagnosed in the Long-Term Care System.

Kidney donation should not lead to deterioration of the donor's health condition, both during the perisurgical period and in the long term. Safety of a living kidney donor becomes a prerequisite for his/her qualification. Detailed diagnostic procedures are performed to exclude any abnormalities of his/her health condition. Additionally, a long-term post-donation follow-up system for kidney donors has been set up in Poland besides the restrictive qualification system. Transplantation centers are obligated to provide a diagnostic procedures for living organ donors as a part of the monitoring of their health condition and to ensure them a medical follow-up for 10 years after the donation. A total of 141 cases of unilateral nephroureterectomy performed in 2003-2014 to obtain a kidney for transplantation were considered. Medical files of post-donation diagnostic or therapeutic methods and their outcomes were retrospectively analyzed. The aim of the study was to assess the efficacy of monitoring of donors' health condition within the framework of the long-term follow-up system for kidney donors in the aspect of detection of the donation-independent abnormalities.

Association of MYH9 rs3752462 and rs5756168 Polymorphisms With Transplanted Kidney Artery Stenosis.

Allelic variants of the MYH9 gene, encoding myosin nonmuscle heavy chain type IIA, have been shown to correlate with diminished glomerular filtration rates and end-stage kidney disease in individuals of Caucasian ancestry. Myosin nonmuscle heavy chain type IIA is expressed during development as well as in injured vessels and kidney structures. We hypothesized that MYH9 risk variants may correlate with kidney artery injury and dysfunctional healing, such as transplant renal artery stenosis (TRAS). Our study aimed at evaluating the association of MYH9 risk allelic variants (rs4821480, rs4821481, rs3752462, rs11089788, rs136211, rs5756168, rs2032487, and rs2239784) with TRAS, defined as >50% renal artery lumen reduction. Genotyping was performed with the use of custom Taqman genotyping assays on DNA samples (n = 295) from white deceased-donor kidney transplant recipients and genomic DNA from the corresponding donors. Statistical analysis was performed with the use of Kaplan-Meier estimates, log-rank tests, and proportional hazard Cox models. Recipients carrying TT in rs5756168 experienced diminished risk of TRAS (hazard ratio [HR], 0.31; P < .009), whereas organs carrying CC in rs3752462 were exposed to excessive TRAS risk (HR, 2.54; P < .047). In multivariate stepwise analysis TRAS was 10.9-fold increased in kidneys originating from rs3752462 CC, whereas the risk was decreased 3.45-fold (adjusted HR, 0.29) in recipients carrying rs5756168 TT (P < .007 and P < .033, respectively). Intracranial bleeding or trauma compared with other mechanisms of donor death diminished TRAS risk by 87% and 91%, respectively (P < .030 and P < .017). Our study is the first to identify genetic predisposition to transplant renal artery stenosis.

Characterization of patients referred for non-specific intellectual disability testing: the importance of autosomal genes for diagnosis.

Genetic testing for non-specific intellectual disability (ID) presents challenges in daily clinical practice. Historically, the focus of the genetic elucidation of non-specific ID has been on genes on the X chromosome, and recent research has brought attention to the growing contribution of autosomal genes. In addition, next-generation sequencing (NGS) has greatly improved the ability to simultaneously analyze multiple genetic loci, making large panel testing a practical approach to testing for non-specific ID. We performed NGS analysis of a total of 90 genes implicated in non-specific ID. The 90 genes included 56 X-linked genes and 34 autosomal genes. Pathogenic variants were identified in 11 of 52 (21%) patient samples. Nine of the eleven cases harbored mutations in autosomal genes including AP4B1, STXB1, SYNGAP1, TCF4 and UBE3A. Our mutation-positive cases provide further evidence supporting the prevalence of autosomal mutations in patients referred for non-specific ID testing and the utility of their inclusion in multi-gene panel analysis.

The effect of pregnancy on humoral rejection in patients after vascularized organ transplantation.

The aim of the study was to evaluate the effect of pregnancy on the production of donor- and nondonor-specific anti-human leukocyte antigen antibodies (anti-HLA Abs) in organ allograft recipients. The study group included four pregnant kidney (RT) and four liver (LT) transplant recipients. The genotype of HLA class I (A, B) and class II (DR) antigens was assessed. Anti-HLA antibodies class I and II were evaluated between 36 and 40 weeks' gestation. Two different control groups consisted of the following: group I (n=8) with nonpregnant RT (n=6) and LT recipients (n=2), and group II with healthy pregnant women (n=10) with anti-HLA Abs detected between 38 and 41 weeks' gestation. The HLA genotype was determined in fathers of the fetuses from the study group and group II controls. Half of group II controls had donor-specific anti-HLA (A, B, and/or DR) Abs, while nondonor-specific anti-HLA Abs were detected in all subjects from that group. Anti-HLA Abs were found in all group II controls. In the study group, anti-HLA Abs were found in only two LT recipients and one RT recipient, but they were not confirmed as donor-specific. Anti-HLA antibodies were not detected in the study group, whereas six out of ten group II controls had anti-HLA Abs against the HLA of the child's father. Pregnancy in vascularized organ recipients does not trigger the mechanism of humoral rejection involving anti-HLA class I and II antibodies with a potentially adverse impact on graft function.

Deletion of MAP2K2/MEK2: a novel mechanism for a RASopathy?

RASopathies are a class of genetic syndromes caused by germline mutations in genes encoding Ras/mitogen-activated protein kinase (Ras/MAPK) pathway components. Cardio-facio-cutaneous (CFC) syndrome is a RASopathy characterized by distinctive craniofacial features, skin and hair abnormalities, and congenital heart defects caused by activating mutations of BRAF, MEK1, MEK2, and KRAS. We define the phenotype of seven patients with de novo deletions of chromosome 19p13.3 including MEK2; they present with a distinct phenotype but have overlapping features with CFC syndrome. Phenotypic features of all seven patients include tall forehead, thick nasal tip, underdeveloped cheekbones, long midface, sinuous upper vermilion border, tall chin, angular jaw, and facial asymmetry. Patients also have developmental delay, hypotonia, heart abnormalities, failure to thrive, obstructive sleep apnea, gastroesophageal reflux and integument abnormalities. Analysis of epidermal growth factor-stimulated fibroblasts revealed that P-MEK1/2 was ∼50% less abundant in cells carrying the MEK2 deletion compared to the control. Significant differences in total MEK2 and Sprouty1 abundance were also observed. Our cohort of seven individuals with MEK2 deletions has overlapping features associated with RASopathies. This is the first report suggesting that, in addition to activating mutations, MEK2 haploinsufficiency can lead to dysregulation of the MAPK pathway.

[Radiologic picture of maxillary sinus aspergilloma]. / Obraz radiologiczny grzybniaka kropidlakowego zatoki szczekowej.

INTRODUCTION: Mycotic infection of paranasal sinus could be the etiological factor of chronic sinusitis. The increase in number of fungal sinusitis cases have been reported recently among nonimmunocompromised patient after endodontic treatment of maxillary teeth. Nonspecific clinical signs and incorrect radiologic pictures interpretation as well as loss of therapeutic standards seems to be the cause of false negative diagnosis and difficulties in treatment of fungal sinusitis. AIM OF THE STUDY: Clinical and radiological picture of maxillary sinus aspergillosis was described in this paper. MATERIAL AND METHODS: In the period of 2006-2009 in the Department of Maxillo-Facial Surgery 19 patient with fungal maxillary sinusitis was treated. The endodontic treatment of maxillary teeth of the related side was performed previously in 80% examined cases. In 2 cases there were immunocompromised patients with immunosuppressive treatment. In 16 cases patients were referred to our Department due to metallic foreign body of the maxillary sinus. Routine diagnostic radiological imaging was performed in each case: paranasal sinus view--Water's view and panoramic radiograph (orthopantomograph). In 4 cases imaging was extended with computer tomography (CT) visualization. The surgical treatment was performed in each case. The final diagnosis was puted on histopathological examination and fungal culture. RESULTS: In 16 cases of analysed group histopathological examination and fungal culture revealed aspergilosis. In 2 cases fungal culture was negative, but histopathology slices confirm presence of hyphae of Aspergillus. In 1 case the root canal sealer was found in the maxillary sinus. In none case invasive form of aspergillosis was confirmed. In all cases Water's view of paranasal sinuses and ortopantomograph showed partially or totally clouded sinus with well-defined, single or multifocal radiopaque object similar to metallic foreign body. Characteristic finding in CT imaging was well-defined radiodence concretions that have been attributed to calcium deposits in inflammatory changed mucosa, that might suggest "foreign body" picture. In 1 to 3 years follow-up control there was a recurrence of symptoms in one case. CONCLUSIONS: Foreign body of maxillary sinus have to be differentiated with aspergilosis. Metallic "foreign body" view in maxillary sinus seems to be characteristic sign of aspergillosis. The most often form of maxillary sinus aspergilosis is aspergilloma.

Femoral-facial syndrome: Prenatal diagnosis and clinical features. Report of three cases.

The objective of our article is to illustrate the earliest prenatal sonographic diagnosis of femoral-facial syndrome (FFS) and to illustrate the spectrum of clinical manifestations of this condition. We present serial sonographic evaluation with 3D evaluation in two fetuses diagnosed prenatally with FFS and the postnatal findings in three patients (one fetus following pregnancy interruption and two newborns one of whom was diagnosed prenatally) with FFS. The two patients with prenatally diagnosed FFS were found to have femoral shortening and characteristic facial features, one 12 weeks of gestation, and one at 15 weeks of gestation. The sonographic findings in the two prenatally diagnosed patients were confirmed after delivery. We also present a third patient who was diagnosed at delivery in whom the diagnosis was missed at a routine prenatal sonogram at 19 weeks of gestation. The patients reported herein expand the clinical spectrum of FFS. The utility of sonographic evaluation in diagnosis of the facial appearance and of the bony abnormalities in this condition is emphasized.

Charge separation, stabilization, and protein relaxation in photosystem II core particles with closed reaction center.

The fluorescence kinetics of cyanobacterial photosystem II (PSII) core particles with closed reaction centers (RCs) were studied with picosecond resolution. The data are modeled in terms of electron transfer (ET) and associated protein conformational relaxation processes, resolving four different radical pair (RP) states. The target analyses reveal the importance of protein relaxation steps in the ET chain for the functioning of PSII. We also tested previously published data on cyanobacterial PSII with open RCs using models that involved protein relaxation steps as suggested by our data on closed RCs. The rationale for this reanalysis is that at least one short-lived component could not be described in the previous simpler models. This new analysis supports the involvement of a protein relaxation step for open RCs as well. In this model the rate of ET from reduced pheophytin to the primary quinone Q(A) is determined to be 4.1 ns(-1). The rate of initial charge separation is slowed down substantially from approximately 170 ns(-1) in PSII with open RCs to 56 ns(-1) upon reduction of Q(A). However, the free-energy drop of the first RP is not changed substantially between the two RC redox states. The currently assumed mechanistic model, assuming the same early RP intermediates in both states of RC, is inconsistent with the presented energetics of the RPs. Additionally, a comparison between PSII with closed RCs in isolated cores and in intact cells reveals slightly different relaxation kinetics, with a approximately 3.7 ns component present only in isolated cores.

Clinical and molecular delineation of the 17q21.31 microdeletion syndrome.

BACKGROUND: The chromosome 17q21.31 microdeletion syndrome is a novel genomic disorder that has originally been identified using high resolution genome analyses in patients with unexplained mental retardation. AIM: We report the molecular and/or clinical characterisation of 22 individuals with the 17q21.31 microdeletion syndrome. RESULTS: We estimate the prevalence of the syndrome to be 1 in 16,000 and show that it is highly underdiagnosed. Extensive clinical examination reveals that developmental delay, hypotonia, facial dysmorphisms including a long face, a tubular or pear-shaped nose and a bulbous nasal tip, and a friendly/amiable behaviour are the most characteristic features. Other clinically important features include epilepsy, heart defects and kidney/urologic anomalies. Using high resolution oligonucleotide arrays we narrow the 17q21.31 critical region to a 424 kb genomic segment (chr17: 41046729-41470954, hg17) encompassing at least six genes, among which is the gene encoding microtubule associated protein tau (MAPT). Mutation screening of MAPT in 122 individuals with a phenotype suggestive of 17q21.31 deletion carriers, but who do not carry the recurrent deletion, failed to identify any disease associated variants. In five deletion carriers we identify a <500 bp rearrangement hotspot at the proximal breakpoint contained within an L2 LINE motif and show that in every case examined the parent originating the deletion carries a common 900 kb 17q21.31 inversion polymorphism, indicating that this inversion is a necessary factor for deletion to occur (p<10(-5)). CONCLUSION: Our data establish the 17q21.31 microdeletion syndrome as a clinically and molecularly well recognisable genomic disorder.

Survival of 231 cervical cancer patients, treated by radical hysterectomy, according to clinical and histopathological features.

PURPOSE OF INVESTIGATION: The purpose of the study was to estimate the five-year survival of cervical cancer patients after radical hysterectomy, taking into account clinical data and histopathological parameters. METHODS: 231 patients with invasive cervical carcinoma were diagnosed, surgically treated--Piver III--and followed-up. Histological examination of specimens was performed according to the British NHS-CSP guidelines. RESULTS: We discovered no statistical significance as regards age at diagnosis, age at menarche and menopause, and number of pregnancies, deliveries and abortions, in relation to survival. We concluded that the clinical stage according to FIGO classification influenced survival. Statistical significances were: Ia2 vs Ib, Ib vs IIa and IIa vs more advanced than IIa. The following histopathological parameters correlated with survival: depth of cervical invasion, primary lesion volume, and parametrial, uterine, vaginal and lymph node involvement. Using Cox's proportional hazards model we found that only lymph node status and FIGO staging were independent parameters correlating with survival and mortality risk in our study. CONCLUSION: Prognostic indexes classifying patients at specific disease stages into different categories of risk should be based on histopathological features listed above. Such indexes are yet to be validated in larger, prospective studies conducted in different patient populations.

Clinical, enzymatic and molecular characterization of nine new patients with malonyl-coenzyme A decarboxylase deficiency.

We report nine new patients with malonic aciduria associated with enzyme-confirmed malonyl-CoA decarboxylase (MCD) deficiency in eight. Clinical details were available on eight, and molecular genetic characterization was obtained for nine. As for 15 previously described patients, cardinal clinical manifestations included developmental delay and cardiomyopathy; metabolic perturbations (e.g. acidosis) and seizures, however, were infrequent or not observed in our patients. For all, detection of elevated malonic acid in urine (+/- increased C3DC acylcarnitine by analysis employing tandem mass spectrometry) led to pursuit of enzyme studies. MCD activities (nmol/h PER mg protein) revealed: control (n = 22), 16.2 +/- 1.8 (SEM; range 5.7-46.2); patients (n = 8, assayed in duplicate), 1.7 +/- 0.3 (10% of parallel control; range 0.6-2.8). Molecular characterization by DNA sequence analysis and multiplex ligation-dependent probe amplification revealed nine novel mutations (c.796C>T; p.Gln266X, c.481delC; p.Leu161CysfsX18, c.1367A>C; p.Tyr456Ser, c.1319G>T; p.Ser440Ile, c.1430C>T; p.Ser477Phe, c.899G>T; p.Gly300Val, c.799-1683_949-1293del3128, and two other large genomic deletions comprising exons 1 or the complete gene) and two known mutations in the MLYCD gene. Our findings increase the number of enzyme-confirmed MCD-deficient patients by >50%, and expand our understanding of the phenotypic and molecular heterogeneity of this rare disorder.

Kinetics and mechanism of electron transfer in intact photosystem II and in the isolated reaction center: pheophytin is the primary electron acceptor.

The mechanism and kinetics of electron transfer in isolated D1/D2-cyt(b559) photosystem (PS) II reaction centers (RCs) and in intact PSII cores have been studied by femtosecond transient absorption and kinetic compartment modeling. For intact PSII, a component of approximately 1.5 ps reflects the dominant energy-trapping kinetics from the antenna by the RC. A 5.5-ps component reflects the apparent lifetime of primary charge separation, which is faster by a factor of 8-12 than assumed so far. The 35-ps component represents the apparent lifetime of formation of a secondary radical pair, and the approximately 200-ps component represents the electron transfer to the Q(A) acceptor. In isolated RCs, the apparent lifetimes of primary and secondary charge separation are approximately 3 and 11 ps, respectively. It is shown (i) that pheophytin is reduced in the first step, and (ii) that the rate constants of electron transfer in the RC are identical for PSII cores and for isolated RCs. We interpret the first electron transfer step as electron donation from the primary electron donor Chl(acc D1). Thus, this mechanism, suggested earlier for isolated RCs at cryogenic temperatures, is also operative in intact PSII cores and in isolated RCs at ambient temperature. The effective rate constant of primary electron transfer from the equilibrated RC* excited state is 170-180 ns(-1), and the rate constant of secondary electron transfer is 120-130 ns(-1).

Bacteriophages and transplantation tolerance.

Our recent findings suggest that bacteriophages (phages) may not only eliminate bacteria, but also modulate immune functions. In this communication, we demonstrate that phages may strongly inhibit human T-cell activation and proliferation as well as activation of the nuclear transcription factor NF-kappaB in response to a viral pathogen. Phage administration in vivo can diminish cellular infiltration of allogeneic skin allografts. Thus, phage treatment should be considered in antibiotic-resistant posttransplantation infections. Furthermore, phages could find a broader application in clinical transplantation.

Beta 3 integrin expression on T cells from renal allograft recipients.

Recent studies emphasize the paramount significance of beta 3 integrin in cell adhesion and homing, which may be particularly relevant in cancer progression and metastasis. In contrast, the presence and potential role of beta 3 on human T cells is practically unknown. We show that T cells can express significant amounts of alpha-beta 3 integrin (CD41/CD61), and the expression of alpha(v)-beta 3 (CD51/CD61) remains very low. T-cell beta 3 integrin is probably transferred by platelet-derived microparticles.

Maternal urinary steroid profiles in prenatal diagnosis of Smith-Lemli-Opitz syndrome: first patient series comparing biochemical and molecular studies.

Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive disorder caused by reduced activity of 7-dehydrocholesterol (7DHC) reductase, resulting in a decreased level of cholesterol and increased concentrations of 7DHC and 8DHC in body fluids and tissues. Ten pregnancies at 25% risk of SLOS underwent prenatal testing. Diagnostic studies included DHCR7 mutation analysis in chorionic villus samples, amniotic fluid sterol analysis and serial measurements of oestriol (E3), pregnanetriol (PT), 7-dehydropregnanetriol (7DHPT) and 8-dehydroesteriol (8DHE3) concentrations in maternal urine samples obtained between 9 and 20 weeks of gestation. All tests were diagnostic and revealed nine unaffected foetuses (two normal homozygotes and seven DHCR7 heterozygotes) and one affected foetus. In the affected pregnancy, 7DHC and 8DHC in amniotic fluid were 9.87 and 3.7 microg/ml, respectively [reference range (RR) 0.0026 +/- 0.0015 microg/ml and not detectable, respectively] and maternal urinary steroid analyses showed increased ratios of 7DHPT/PT and 8DHE3/E3 of 0.74 and 1.7, respectively (RR 0-0.0147 and 0-0.019). In the heterozygous foetuses, 7DHPT/PT and 8DHE3/E3 ratios did not exceed those found in 48 normal controls. This is the first series of prenatal diagnostic testing for SLOS where non-invasive biochemical testing was performed in tandem with invasive diagnostic testing. We conclude that steroid measurements in maternal urine are a reliable means of prenatal diagnosis for SLOS.

SLOS carrier frequency in Poland as determined by screening for Trp151X and Val326Leu DHCR7 mutations.

Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive disorder of cholesterol biosynthesis caused by mutations in the DHCR7 gene. Previous studies estimated the prevalence of SLOS between 1 in 10,000 to 1 in 70,358 based on case frequency surveys. Although panethnic, SLOS appears to be most frequent in Central European populations (Czech Republic 1 in 10,000, Slovakia 1 in 15,000 - 1 in 20,000). In Polish individuals with SLOS two DHCR7 mutations, c.452G>A (p.Trp151X) and c.976G>T (p.Val326Leu), account for 65.2% of all observed DHCR7 mutations. We analyzed 2169 samples for the p.Trp151X mutation and 2087 for the p.Val326Leu mutation. The combined carrier frequency of these two mutations of was 2.40+/-0.32%, yielding a calculated incidence of SLOS in Poland of 2.5 4x10(-4)-4.3 5x10(-4) (1 in 2,300 to 1 in 3,937) placing SLOS among the most common recessive genetic disorders in Poland.

Charge separation kinetics in intact photosystem II core particles is trap-limited. A picosecond fluorescence study.

The fluorescence kinetics in intact photosystem II core particles from the cyanobacterium Thermosynechococcus elongatus have been measured with picosecond resolution at room temperature in open reaction centers. At least two new lifetime components of approximately 2 and 9 ps have been resolved in the kinetics by global analysis in addition to several known longer-lived components (from 42 ps to approximately 2 ns). Kinetic compartment modeling yields a kinetic description in full agreement with the one found recently by femtosecond transient absorption spectroscopy [Holzwarth et al. (2005) submitted to Proc. Natl. Acad. Sci. U.S.A.]. We have for the first time resolved directly the fluorescence spectrum and the kinetics of the equilibrated excited reaction center in intact photosystem II and have found two early radical pairs before the electron is transferred to the quinone Q(A). The apparent lifetime for primary charge separation is 7 ps, that is, by a factor of 8-12 faster than assumed on the basis of earlier analyses. The main component of excited-state decay is 42 ps. The effective primary charge separation rate constant is 170 ns(-)(1), and the secondary electron-transfer rate constant is 112 ns(-)(1). Both electron-transfer steps are reversible. Electron transfer from pheophytin to Q(A) occurs with an apparent overall lifetime of 350 ps. The energy equilibration between the CP43/CP47 antenna and the reaction center occurs with a main apparent lifetime of approximately 1.5 ps and a minor 10 ps lifetime component. Analysis of the overall trapping kinetics based on the theory of energy migration and trapping on lattices shows that the charge separation kinetics in photosystem II is extremely trap-limited and not diffusion-to-the-trap-limited as claimed in several recent papers. These findings support the validity of the assumptions made in deriving the earlier exciton radical pair equilibrium model [Schatz, G. H., Brock, H., and Holzwarth, A. R. (1988) Biophys. J. 54, 397-405].