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Abstract Satellite remote sensing is becoming a widely used monitoring technique in coastal sciences. Yet, no benchmarking studies exist that compare the performance of popular satellite-derived shoreline mapping algorithms against standardized sets of inputs and validation data. Here we present a new benchmarking framework to evaluate the accuracy of shoreline change observations extracted from publicly available satellite imagery (Landsat and Sentinel-2). Accuracy and precision of five established shoreline mapping algorithms are evaluated at four sandy beaches with varying geologic and oceanographic conditions. Comparisons against long-term in situ beach surveys reveal that all algorithms provide horizontal accuracy on the order of 10 m at microtidal sites. However, accuracy deteriorates as the tidal range increases, to more than 20 m for a high-energy macrotidal beach (Truc Vert, France) with complex foreshore morphology. The goal of this open-source, collaborative benchmarking framework is to identify areas of improvement for present algorithms, while providing a stepping stone for testing future developments, and ensuring reproducibility of methods across various research groups and applications.

Increasing evidence exists that the gut microbiome influences toxicity as well as outcomes in a variety of cancers. To investigate the role of the gut microbiome in pediatric neuro-oncology, microbiome analysis has been included in multiple prospective pediatric neuro-oncology clinical trials (NCT05009992, NCT04732065, NCT04775485). In these trials, the OMNIgene-GUT tm preservation tubes are used for the collection of the feces. OMNIgene-GUT tm has demonstrated reliability in preserving the composition of the gut microbiome in adults; however, its validation for use in the pediatric population remains limited. Therefore, we compared the quality of the DNA by 16S rRNA gene sequencing after various methods of stabilizing fecal samples in pediatric populations, from the direct freeze method at - 80 °C to preserving samples with OMNIgene-GUT tm at room temperature for various durations. Our results showed that there were no statistically significant differences between the alpha-diversity, and beta-diversity. However, pairwise differential abundance analyses demonstrated that OMNIgene-GUT™ is superior in maintaining microbial community structure compared to storing samples without any preservation method. With the OMNIgene-GUT tm 's stabilization of the fecal samples being superior and its ease-of-use benefits, it proves to be a valid and ideal method of stabilizing fecal samples for current and future pediatric clinical trials., Competing Interests: Declarations. Ethical approval: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Competing interests: Raoull Hoogendijk declares that he has no conflict of interest. Thijs J.M. van den Broek declares that he has no conflict of interest. Hyunju Lee declares that she has no conflict of interest. Sabine Mueller declares that she has no conflict of interest. Cassie Kline declares that she has no conflict of interest. John Bianco declares that he has no conflict of interest. Janetta Top declares that she has no conflict of interest. Marcel R. de Zoete declares that he has no conflict of interest. Lennart Kester declares that he has no conflict of interest. Friso Calkoen declares that he has no conflict of interest. Jasper van der Lugt declares that he has no conflict of interest, (© 2024. The Author(s).)

In patients diagnosed with B-acute lymphoblastic leukemia (B-ALL) or B-non-Hodgkin's lymphoma (B-NHL) relapsing after allogeneic stem cell transplantation (allo-HCT), it is a standard practice to perform anti-CD19 chimeric antigen receptor (CAR) T-cell therapy. When collected from the patient after allo-HCT, the produced CAR-T cells are likely to be donor T-cell-derived, creating unknown safety risks due to their potential allo-reactivity. We therefore performed an EBMT registry-based study on the incidence of graft-versus-host disease (GvHD) in this setting. We included 257 allo-HCT patients (n = 172 ≥ 18 years) with B-ALL or B-NHL, treated with anti-CD19 CAR T-cells (tisagenlecleucel n = 184, brexucabtagene autoleucel n = 43 and axicabtagene ciloleucel n = 30), between 2018 and 2022. Three patients developed aGvHD, whereas 6 patients developed cGvHD after CAR T-cell. The 100-day cumulative incidence (CI) of new aGvHD was 1.6% and the 12-month CI of new cGvHD was 2.8%. The 1-year GvHD relapse-free survival and non-relapse mortality were 52.1% and 4.7%, respectively. Last, with a median follow up of 18.8 months, the 1-year overall survival was 76.8%. In summary, the GvHD rate in allo-HCT patients treated with CAR T-cell therapy is relatively low. Our data support the view that GvHD is not a major safety issue in this setting., Competing Interests: Ethics approval and consent to participate’ statement The EBMT is a non-profit scientific society representing more than 600 transplant centers mainly in Europe. Data are entered, managed, and maintained in a central database with Internet access. The study was conducted in accordance with the EBMT Guidelines for Retrospective Studies and the principles of the Declaration of Helsinki. EBMT centers commit to obtain informed consent according to the local regulations and guidelines applicable at the time in order to report pseudonymized data to the EBMT. Competing interests Guillermo Orti (GO) has no COIs directly related to this study. GO has received honoraria or travel support from Incyte, Jazz, Novartis, Pfizer and Sanofi. He has received research support from Incyte (institutional). Herbert Pichler (HP) declares having received travel grants from Jazz and Neovii. Helene Schoemans (HS) reports having received personal fees from Incyte, Janssen, Novartis, Sanofi and from the Belgian Hematological Society (BHS), as well as research grants from Novartis and the BHS, all paid to her institution and not directly related to this work. She has also received non-financial support (travel grants) from Gilead, Pfizer, the EBMT (European Society for Blood and Marrow transplantation) and the CIBMTR (Center for International Bone Marrow Transplantation Research). Ivan Moiseev (IM) has no COIs directly related to this work. IM has received honoraria from Novartis and J&J. Olaf Penack (OP) has no COIs directly related to this work. OP has received honoraria or travel support from Alexion, Gilead, Jazz, MSD, Neovii, Novartis, Pfizer and Therakos. He has received research support from Incyte and Priothera. He is member of advisory boards to Alexion, Equillium Bio, Jazz, Gilead, Novartis, MSD, Omeros, Orca Bio, Priothera, Sanofi, Shionogi and SOBI., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

COVID-19 has been associated with high mortality in patients treated with Chimeric Antigen Receptor (CAR) T-cell therapy for hematologic malignancies. Here, we investigated whether the outcome has improved over time with the primary objective of assessing COVID-19-attributable mortality in the Omicron period of 2022 compared to previous years. Data for this multicenter study were collected using the MED-A and COVID-19 report forms developed by the EBMT. One-hundred-eighty patients were included in the analysis, 39 diagnosed in 2020, 35 in 2021 and 106 in 2022. The median age was 58.9 years (min-max: 5.2-78.4). There was a successive decrease in COVID-19-related mortality over time (2020: 43.6%, 2021: 22.9%, 2022: 7.5%) and in multivariate analysis year of infection was the strongest predictor of survival (p = 0.0001). Comparing 2022 with 2020-2021, significantly fewer patients had lower respiratory symptoms (21.7% vs 37.8%, p = 0.01), needed oxygen support (25.5% vs 43.2%, p = 0.01), or were admitted to ICU (5.7% vs 33.8%, p = 0.0001). Although COVID-19-related mortality has decreased over time, CAR T-cell recipients remain at higher risk for complications than the general population. Consequently, vigilant monitoring for COVID-19 in patients undergoing B-cell-targeting CAR T-cell treatment is continuously recommended ensuring optimal prevention of infection and advanced state-of-the art treatment when needed., (© 2024. The Author(s).)

Relapsed/refractory T-cell acute lymphoblastic leukemia (ALL)/lymphoma (LBL) represent a significant unmet medical need. WU-CART-007 is a CD7-targeting, allogeneic, fratricide-resistant chimeric antigen receptor T cell product generated from healthy donor T cells. WU-CART-007 was evaluated in a phase 1/2 study with a 3 + 3 dose-escalation design followed by cohort expansion in relapsed/refractory T-ALL/LBL. Patients received one infusion of WU-CART-007 after standard or enhanced lymphodepleting chemotherapy. The primary objectives, to characterize safety and assess the composite complete remission rate, were met. Of 26 patients enrolled, 13 received the recommended phase 2 dose (RP2D) of 900 million cells of WU-CART-007 with enhanced lymphodepletion. The most common treatment-related adverse event was cytokine release syndrome (88.5%; 19.2% grade 3-4). Biochemical abnormalities consistent with grade 2 hemophagocytic lymphohistiocytosis were seen in one patient (3.8%). Grade 1 immune effector cell-associated neurotoxicity syndrome events (7.7%) and one grade 2 acute graft-vs-host disease event occurred. Grade 5 events (11.5%) were due to fungal infection and multi-organ failure. The composite complete remission rate was 81.8% among 11/13 patients evaluable for response at the RP2D. WU-CART-007 at the RP2D demonstrated a high response rate in patients with relapsed/refractory T-ALL/LBL and has the potential to provide a new treatment option. ClinicalTrials.gov registration: NCT04984356., Competing Interests: Additional Declarations: Yes there is potential Competing Interest. Financial: Armin Ghobadi: Honorarium from Kite, a Gilead company; consultancy provided for Amgen, Atara, Bristol Myers Squibb, CRISPR therapeutics, Kite, Novartis, and Wugen; research funding from Amgen, Genentech, and Kite. Ibrahim Aldoss: Ad Board and consultant fees from Wugen, Amgen, KITE, Abbvie, Takeda; Research support: MacroGenics, Abbvie Shannon L. Maude: Clinical trial support from Novartis and Wugen; advisory and study steering committees for Novartis and Wugen; patent pending and licensed to Novartis Pharmaceuticals without royalty for PCT/US2017/044425: Combination Therapies of Car and PD-1 Inhibitors. Bhagirathbhai Dholaria: Institutional research funding, no direct payment: Janssen, Angiocrine, Pfizer, Poseida, MEI, Orcabio, Wugen, Allovir, NCI, Atara, Gilead, Molecular templates, BMS, AstraZeneca, Adicet. Consultation/Advisory board: Janssen, Pluri Biotech, BOXER CAPITAL, Ellipsis pharma, Lumanity, Autolus, Acrotech, ADC therapeutics, Gilead, Global health research, GSK, Roche Rawan Faramand: Advisory Board: Kite/Gilead; Autolus; Consultancy: Sanofi;Research Funding: Kite/Gilead; Novartis Andre Baruchel: Servier: symposia, travels; Jazz: advisory boards; Amgen: symposia; Servier: funding for academic clinical research protocol; Astra Zeneca: advisory board paid to institution Nicolas Boissel: Consultant for Novartis, Amgen, Bristol Myers Squibb, and Jazz Pharmaceuticals; and receives honoraria from Novartis, Amgen, Incyte, Servier, Bristol Myers Squibb, Jazz Pharmaceuticals, Celgene, Sanofi, and Pfizer. Brent Wood: Dr. Wood’s institution receives funding for contract laboratory testing from a number of biopharma companies including two that have products whose efficacy is being evaluated in T-ALL. However, there is no interaction between the services provided for each company. Dr. Wood also is a paid consultant on MRD testing for clinical trials for Amgen, but does not involve products for T-ALL. Haley Irons: Employment in Wugen Ben Capoccia: Employment in Wugen Deborah Masters: Employment and shares in Wugen Justo Gonzalez: Wugen employment Tony Wu: Employment and shares in Wugen Maria del Rosario: Employment and shares in Wugen Alexander Hamil: Employment and shares in Wugen Ouiam Bakkacha: Employment and shares in Wugen, MacroGenics stock John Muth: Employment and shares in Wugen Brett Ramsey: Employment and shares in Wugen Eileen McNulty: Employment and shares in Wugen Matthew L. Cooper: Equity, ownership, employment in Wugen Jan Baughman: Consultant to Wugen; MacroGenics stock Jan Davidson-Moncada: Employment and shares in Wugen John F. DiPersio: Consulting: Rivervest, Bluebird Bio, Vertex, HcBiosciences, SPARC; Equity-ownership WUGEN and Magenta; Research support: MacroGenics, Bioline, Incyte. Support: NCI R35 CA210084, Leukemia and Lymphoma Society SCOR Non-Financial: Armin Ghobadi: Wugen founders include members of Washington University physicians that are colleagues of Dr. Ghobadi. Ryan J. Mattison:Vice chair of the Acute Lymphoblastic Leukemia committee for the National Comprehensive Cancer Netork (NCCN) C. Michel Zwaan: Chair of Hem-iSMART study for T-cell ALL with support from Abbvie and Novartis

Muddy coasts provide ecological habitats, supply food and form a natural coastal defence. Relative sea level rise, changing wave energy and human interventions will increase the pressure on muddy coastal zones. For sustainable coastal management it is key to obtain information on the geomorphology of and historical changes along muddy areas. So far, little is known about the distribution and behaviour of muddy coasts at a global scale. In this study we present a global scale assessment of the occurrence of muddy coasts and rates of coastline change therein. We combine publicly available satellite imagery and coastal geospatial datasets, to train an automated classification method to identify muddy coasts. We find that 14% of the world's ice-free coastline is muddy, of which 60% is located in the tropics. Furthermore, the majority of the world's muddy coasts are eroding at rates exceeding 1 m/yr over the last three decades., (© 2023. The Author(s).)

Background: Natural moisturizing factor (NMF) is used as genotypic and phenotypic biomarker in diagnostics. This study is a side-to-side comparison of two different methods to determine NMF in atopic dermatitis patients: Raman microspectroscopy and stratum corneum tape stripping followed by HPLC., Results: Measured NMF values were significantly correlated (R 2  = .61; p < .0001), both methods demonstrated a concentration-depth dependence of NMF and reduced NMF levels in the carriers of filaggrin null mutations. Good agreement between measurements of left and right arms indicated robustness and good reproducibility of both methods., Conclusions: Both methods showed comparable performance, choice of method will rather be influenced by practical consideration.

Background/objectives: Environmental exposure and personal susceptibility both contribute to the development of hand eczema. In this study, we investigated the effect of loss-of-function mutations in the filaggrin gene (FLG), atopic dermatitis and wet work exposure on the development of hand eczema in apprentice nurses., Methods: Dutch apprentice nurses were genotyped for the four most common FLG mutations; atopic dermatitis and hand eczema history were assessed by questionnaire. Exposure and hand eczema during traineeships were assessed with diary cards., Results: The prevalence of hand eczema during traineeships was higher among subjects with a history of hand eczema reported at inclusion. Hand washing during traineeships and at home increased the risk of hand eczema. After adjustment for the effects of exposure and FLG mutations, an odds ratio of 2.5 (90% confidence interval 1.7-3.7) was found for a history of atopic dermatitis. In this study, an increased risk of hand eczema conferred by FLG mutations could not be shown, but subjects with concomitant FLG mutations and atopic dermatitis showed the highest risk of hand eczema during traineeships., Conclusion: A history of atopic dermatitis, a history of hand eczema and wet work exposure were the most important factors increasing the risk of hand eczema during traineeships., (© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Atopic dermatitis (AD) and loss-of-function mutations in the filaggrin gene (FLG) are both associated with chronic irritant contact dermatitis (ICD). As FLG mutations also are a major risk factor for AD, it is not clear whether FLG mutations are an independent risk factor for ICD or whether the risk is mediated by AD., Objectives: To investigate the relative contribution and interaction of FLG mutations and AD in German patients with occupational ICD and controls (vocational school apprentices)., Methods: A total of 634 patients and 393 controls were genotyped for R501X, 2282del4, R2447X and S3247X. Current or past flexural eczema was used as an indicator of AD., Results: FLG mutations were found in 15·9% of the patients with ICD and 8·3% of the controls, with a crude odds ratio (OR) of 2·09 [95% confidence interval (CI) 1·33-3·28] for the combined genotype. The adjusted OR for FLG mutations, corrected for AD, was 1·62 (95% CI 1·01-2·58). Subjects with AD were at approximately three times higher risk of developing ICD than controls (OR 2·89; 95% CI 2·09-3·99). There was no evidence of an interaction between these two risk factors., Conclusions: Our results indicate that both FLG mutations and AD increase the risk of ICD. Individuals with concurrent FLG mutations and AD are at the highest risk of developing ICD., (© 2012 The Authors. BJD © 2012 British Association of Dermatologists.)

Background: The carriers of loss-of-function mutations in the filaggrin gene (FLG) have reduced levels of natural moisturizing factor (NMF) in the stratum corneum. The concentration of NMF components which are formed by filaggrin protein breakdown in the stratum corneum might therefore be useful as a biomarker of the FLG genotype. OBJECTIVES To investigate the feasibility of different sampling methods for the determination of two NMF components, 2-pyrrolidone-5-carboxylic acid (PCA) and urocanic acid (UCA), in the stratum corneum as biomarkers for the FLG genotype., Methods: PCA and UCA from the stratum corneum were sampled by using a tape stripping technique and an extraction technique using skin patches containing potassium hydroxide (KOH). The concentrations of PCA and UCA were measured by high-performance liquid chromatography. Eleven carriers of an FLG mutation and 10 individuals wild type for the two most common FLG mutations (R501X and R2447X) [corrected] were included in the study., Results: The most significant difference between the FLG genotypes was found for PCA sampled by the tape stripping technique. The mean values of PCA obtained by the tape stripping technique were, respectively, 0.18, 0.50 and 1.64 mmol g(-1) protein in homozygous (or compound heterozygous), heterozygous and wild-type genotypes (P < 0.005 homozygous vs. heterozygous; P < 0.0001 heterozygous vs. wild type). The tape stripping technique showed less intrasubject variation compared with the KOH patches, in particular when the concentrations of UCA and PCA on the tape strips were normalized for protein amount., Conclusions: The concentration of PCA in the stratum corneum collected by tape stripping showed it to be a feasible biomarker of the FLG genotype.

Background: Polymorphisms in the filaggrin (FLG) gene, which result in loss of filaggrin production, may alter the skin barrier and are a well-known predisposing factor for atopic dermatitis., Objectives: As a compromised skin barrier and atopic dermatitis are risk factors for chronic irritant contact dermatitis (CICD), our objective was to determine whether polymorphisms in the FLG gene contribute towards susceptibility to occupational CICD., Methods: In a case-control study, the FLG polymorphisms R501X and 2282del4 were determined in 296 patients with CICD. Two hundred and seventeen apprentices in vocational training for high-risk occupations for CICD were chosen as controls. Data on skin diseases and conditions were collected by dermatologists from patients and by means of questionnaires from controls., Results: Heterozygotes for R501X and 2282del4, FLG null alleles, were more frequent among patients with CICD (12.5%) compared with controls (6.9%), resulting in an odds ratio of 1.91 (95% confidence interval 1.02-3.59). Among patients who were carriers of a FLG null allele, we found a higher lifetime prevalence of flexural eczema (62% vs. 46%; P = 0.04) and a higher atopy score (13 vs. 10 points; P = 0.05) compared with noncarriers. In the apprentice group, signs of dermatitis before the start of the vocational training were four times more prevalent in carriers (43%) than in noncarriers (10%; P < 0.001)., Conclusions: Our study shows that FLG null alleles are associated with increased susceptibility to CICD; whether or not the FLG null allele is an independent risk factor needs further study.

Background: Cytokines play an important role in skin inflammation., Objectives: We determined whether polymorphisms in cytokine genes contribute to the occurrence of occupational chronic irritant contact dermatitis (CICD)., Methods: In a case-control study, 9 polymorphisms in the genes coding for interleukin (IL)-1 alpha, IL-1 beta, IL-8, IL-10, and tumour necrosis factor (TNF)-alpha were determined in 197 patients with CICD. 217 apprentices in vocational training for high-risk occupations for CICD served as controls., Results: For all polymorphisms, no differences in genotype distributions were found between patients and controls. However, in patients with self-reported low levels of wet work and irritant exposure, more TNFA -308 variant genotypes (G/A and A/A) were present compared with those exposed to higher levels or controls, which indicates a TNFA-induced increase of susceptibility. In patients with TNFA -308 variant genotypes, the prevalence of flexural eczema was higher (48% and 57%) compared with that in patients presented with wild-type genotype (30%). Regarding IL1A -889, prevalence of symptoms of dermatitis was lower in apprentices with T/T or C/T genotype (32% and 36%) compared with wild-type genotype (54%, C/C). This indicates a protective effect of these variant alleles in acquiring hand dermatitis., Conclusions: This study provides evidence that some genetic variations alter susceptibility to (chronic) dermatitis. Knowledge of the impact of genetic differences on the risk of CICD is essential in predictive testing of individuals at risk.

In the present study, we investigate whether genetic polymorphism in enzymes involved in the metabolism of organic solvents influences susceptibility to chronic solvent encephalopathy (CSE), which is one of the major effects of long-term exposure to organic solvents. Polymorphisms in the genes encoding CYP1A1, CYP2E1, EPHX1, GSTM1, GSTT1 and GSTP1 enzymes were determined in a group of male CSE patients (N=97) and controls (N=214). The selection of the patients was based on a standard diagnostic protocol, including interviews, neuropsychological tests and questionnaires directed to somatic, cognitive and mood symptoms and exposure, in combination with well-defined decision rules. As controls, healthy workers of similar socio-economic background, without memory problems and with no known exposure to organic solvents, were included in the study. Comparing patients and controls, higher frequencies of the variant *5B allele of the CYP2E1 gene (OR: 5.8; 95% CI: 1.8-18.8) and of the variant GSTP1*C allele (OR: 0.40; 95% CI: 0.17-0.94) were found. Homozygous carriers of the exon 4 EPHX1 Arg139 variant allele had a lower risk (OR: 0.25; 95% CI: 0.06-1.13). The present study indicates that genetic polymorphism of CYP2E1, EPHX1 and GSTP1 modify the risk of developing CSE.

We developed a sensitive method for determination of polyethylene glycols (PEGs) of different molecular weight (MW) in the human stratum corneum (SC) obtained by tape stripping. The analysis is based on derivatization with pentafluoropropionic anhydride (PFPA) and gas chromatography-electron capture detection (GC-ECD). The identification and quantification of PEGs was done using individual oligomers. The method showed to be suitable for studying permeability in normal and impaired skin with respect to MW in the range of 150-600 Da.

A spectroscopic characterization is presented of the minor photosystem II chlorophyll a/b-binding protein CP29 (or the Lhcb4 protein) from spinach, prepared by a modified form of a published protocol [Henrysson, T., Schroder, W. P., Spangfort, M. & Akerlund, H.-E. (1989) Biochim. Biophys. Acta 977, 301-308]. The isolation procedure represents a quicker, cheaper means of isolating this minor antenna protein to an equally high level of purity to that published previously. The pigment-binding protein shows similarities to other related light-harvesting complexes (LHCs), including the bulk complex LHCIIb but more particularly another minor antenna protein CP26 (Lhcb5). It is also, in the main, similar to other preparations of CP29, although some significant differences are discussed. In common with CP26, the protein binds about six chlorophyll a and two chlorophyll b molecules. Two chlorophyll b absorption bands are present at 638 and 650 nm and they are somewhat more pronounced than in a recent report [Giuffra, E., Zucchelli, G., Sandonà, D., Croce, R., Cugini, D., Garlaschi, F.M., Bassi, R. & Jennings, R.C. (1997) Biochem. 36, 12984-12993]. The bands give rise to positive and negative linear dichroism, respectively; both show negative CD bands (cf. bands with similar properties at 637 and 650 nm in CP26). Chlorophyll a absorption is dominated by a large contribution at 674 nm which also shows similarities to the major band in LHCIIb and CP26, while (as for CP26) a reduction in absorption around 670 nm is observed relative to the bulk complex. Principal differences from LHCIIb and CP26, and from other CP29 preparations, occur in the carotenoid region.

Photosystem II is a multisubunit pigment-protein complex embedded in the thylakoid membranes of chloroplasts. It utilizes light for photochemical energy conversion, and is heavily involved in the regulation of the energy flow. We investigated the structural organization of photosystem II and its associated light-harvesting antenna by electron microscopy, multivariate statistical analysis, and classification procedures on partially solubilized photosystem II membranes from spinach. Observation by electron microscopy shortly after a mild disruption of freshly prepared membranes with the detergent n-dodecyl-alpha,D-maltoside revealed the presence of several large supramolecular complexes. In addition to the previously reported supercomplexes [Boekema, E. J., van Roon, H., and Dekker, J. P. (1998) FEBS Lett. 424, 95-99], we observed complexes with the major trimeric chlorophyll a/b protein (LHCII) in a third, L-type of binding position (C2S2M0-2L1-2), and two different types of megacomplexes, both identified as dimeric associations of supercomplexes with LHCII in two types of binding sites (C4S4M2-4). We conclude that the association of photosystem II and its associated light-harvesting antenna is intrinsically heterogeneous, and that the minor CP26 and CP24 proteins play a crucial role in the supramolecular organization of the complete photosystem. We suggest that different types of organization form the structural basis for photosystem II to specifically react to changing light and stress conditions, by providing different routes of excitation energy transfer.

Energy transfer from chlorophyll b (Chl b) to chlorophyll a (Chl a) in monomeric preparations of light-harvesting complex II (LHCII) from spinach was studied at 77 K using pump-probe experiments. Sub-picosecond excitation pulses centered at 650 nm were used to excite preferentially Chl b and difference absorption spectra were detected from 630 to 700 nm. Two distinct Chl b to Chl a transfer times, approximately 200 fs and 3 ps, were found. A clearly distinguishable energy transfer process between Chl a molecules occurred with a time constant of 18 ps. The LHCII monomer data are compared to previously obtained LHCII trimer data, and both data sets are fitted simultaneously using a global analysis fitting routine. Both sets could be described with the following time constants: 140 fs, 600 fs, 8 ps, 20 ps, and 2.9 ns. In both monomers and trimers 50% of the Chl b to Chl a transfer is ultrafast (<200 fs). However, for monomers this transfer occurs to Chl a molecules that absorb significantly more toward shorter wavelengths than for trimers. Part of the transfer from Chl b to Chl a that occurs with a time constant of 600 fs in trimers is slowed down to several picoseconds in monomers. However, it is argued that observed differences between monomers and trimers should be ascribed to the loss of some Chl a upon monomerization or a shift of the absorption maximum of one or several Chl a molecules. It is concluded that Chl b to Chl a transfer occurs only within monomeric subunits of the trimers and not between different subunits.

A spectral and functional assignment of the xanthophylls in monomeric and trimeric light-harvesting complex II of green plants has been obtained using HPLC analysis of the pigment composition, laser-flash induced triplet-minus-singlet, fluorescence excitation, and absorption spectra. It is shown that violaxanthin is not present in monomeric preparations, that it has most likely a red-most absorption maximum at 510 nm in the trimeric complex, and that it is involved in both light-harvesting and Chl-triplet quenching. Two xanthophylls (per monomer) have an absorption maximum at 494 nm. These play a major role in both singlet and triplet transfer. These two are most probably the two xanthophylls resolved in the crystal structure, tentatively assigned to lutein, that are close to several chlorophyll molecules [Kühlbrandt, W., Wang, N. D., & Fujiyoshi, Y. (1994) Nature 367, 614-621]. A last xanthophyll contribution, with an absorption maximum at 486 nm, does not seem to play a significant role in light-harvesting or in Chl-triplet quenching. On the basis of the assumption that the two structurally resolved xanthophylls are lutein, this 486 nm absorbing xanthophyll should be neoxanthin. The measurements demonstrate that violaxanthin is connected to at least one chlorophyll a with an absorption maximum near 670 nm, whereas the xanthophylls absorbing at 494 nm are connected to at least one chlorophyll a with a peak near 675 nm.

In order to identify cerebellar terminals in the cat inferior olive which contain gamma-aminobutyric acid (GABA), a technique was developed combining anterograde transport of wheatgerm agglutinine-conjugated horseradish peroxidase (WGA-HRP) with gold-immunocytochemistry. With this technique both the HRP reaction product and the immunogold labelling can be visualized in a single ultrathin section. Our results suggest that most, if not all of the WGA-HRP-labelled cerebellar terminals in the rostral medial accessory olive (MAO) and the rostral principal olive (PO) are GABAergic. In an additional experiment the GABAergic innervation of the rostral MAO was studied in combination with WGA-HRP anterograde tracing from the rostral mesencephalon. In this case the WGA-HRP-labelled terminals were never found to be GABA-positive.