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Background/Aims JAK inhibitors (JAKi) are relatively recently licenced for treatment of inflammatory arthritis. Therefore, long term data regarding outcomes for patients cycling through multiple JAKi are lacking. However, one recent international cohort study (Pombo Suarez et al) suggested cycling JAKi is similarly efficacious as switching to an alternative biologic DMARD after initial treatment failure. The aim of this study was to assess outcomes for patients switching JAKi in a large, UK teaching hospital. Methods This was a retrospective cohort study of patients prescribed a JAKi for inflammatory arthritis at Sheffield Teaching Hospitals. Patients who had received two or more JAKi were identified through a local biologic database. Demographic data, antibody status, concomitant medications, previous biologics, and reasons for switching therapy were collected. Results We identified 20 patients who had cycled through JAKi. The diagnosis was Rheumatoid arthritis in 75% (n = 15) of patients. The remaining patients had Psoriatic arthritis (n = 3), seronegative inflammatory arthritis (n = 1) or axial spondyloarthritis (n = 1). 95% (n = 19) of patients were female. 50% of patients used concomitant DMARD therapy and 15% were prescribed concomitant steroids. 85% (n = 17) of patients had received two JAKi and 15% (n = 3) had received three. Initial JAKi prescribed was Baricitinib in 40%, Tofacitinib in 40%, Filgotinib in 10% and Upadacitinib in 10% of patients. The most frequent reason for cycling JAKi was secondary loss of efficacy, affecting 40% (n = 8) of patients. The duration of treatment before loss of effect ranged from 6-45 months (IQR 12-31 months). 100% of these patients remain on their second JAKi with good response. 35% (n = 7) of patients stopped initial JAKi therapy due to side effects. These included gastrointestinal upset, headaches, and rash. 86% (n = 6) of these patients did not tolerate a second JAKi due to re-occurrence of the same side effect, including one patient with recurrence of the same side effect on a third JAKi. One patient who had headaches with their first JAKi has remained well on their second JAKi. 20% (n = 4) of patients changed therapy due to primary nonresponse to initial JAKi. One patient failed to respond sufficiently to either JAKi and alternative treatment was commenced. Three patients responded to a second JAKi, although two later lost efficacy and are currently responding well to a third JAKi. One patient switched JAKi due to cardiovascular risk with Tofacitinib. Conclusion This study supports recent studies in finding that cycling JAKi in patients who lose efficacy or do not respond to initial JAKi can be an effective treatment strategy. However, in patients who stop initial JAKi due to side effects, cycling to a further JAKi is less likely to be successful, with recurrence of side effects in most cases. Disclosure E.M. Quinlan: None. M. Cox: None. J.R. Maxwell: Honoraria; BMS, Pfizer, Abbvie, Lilly, Gilead.

Background/Aims Biological disease-modifying anti-rheumatic drugs (bDMARDs) account for a significant proportion of pharmaceutical expenditure in the NHS. In 2016, Manchester Royal Infirmary implemented the first Biological Rheumatology MDT to reduce variation in biologic prescribing. A similar care model was implemented in Sheffield Teaching Hospitals (STH), which we evaluate here. This evaluation aimed to answer the following questions: has the MDT improved the cost-effectiveness of biologic prescribing in STH, do anti-drug antibodies (ADAB) influence subsequent biologic treatment, are IL-6 or JAK inhibitor monotherapies more clinically effective than anti-TNF monotherapy in rheumatoid arthritis (RA) and what happens when no biologic treatment is advised? Methods The MDT keeps a real-time record of discussions containing patient demographics, previous therapies, and MDT decisions. This includes all MDT meetings over a 32-month period. This was merged with a database containing the current biologic therapy of all STH rheumatology patients, and a notes-review confirmed accuracy. For economic evaluation, a similar database was produced for patients commenced on biologics in the 6 months prior the MDTs introduction. Results Over the 32-month period of the MDT, there were 994 discussions about 796 patients. Concomitant conventional DMARD therapy was used in 63% of patients. 89% of patients discussed continue to use biologic therapies. The biologic MDT resulted in a 26% decrease in cost during the first 6 months of the MDT when compared to 6 months before the MDT. This was attributed to the increased use of biosimilars and evidence-based decision making. There was improved drug survival, with 28% of pre-MDT patients requiring a subsequent change to an alternative biologic, compared to 21% of patients in the MDT group. Secondary ADAB-positive failure is the commonest cause of ADAB-forming anti-TNF failure across all diagnoses. This commonly prompts a class switch in RA (where there are a wider range of NICE approved therapies), and a switch to etanercept (with the advantage of reduced immunogenicity when compared to other Anti-TNFs) in ankylosing spondylitis and psoriatic arthritis. IL-6 inhibitors and JAK inhibitors perform more favourably as monotherapies than anti-TNFs. 21% of patients in each of the IL6 inhibitor and JAK inhibitor monotherapy groups required alternative biologic therapy, compared to 42% in the anti-TNF monotherapy group. Of the 51 patients in whom no biologic was initially advised, 61% went on to receive a biologic. Conclusion The bDMARD MDT in STH has improved the standardisation of biologic prescribing across the rheumatology team. This evaluation has demonstrated significant improvements in cost-effectiveness and treatment retention compared to the 6-month period prior to the MDTs introduction. The evidence-base is effectively enforced by the MDT, which improves patient experience by improving drug survival. We recommend implementing a biologics MDT within other services to ensure equitable and cost-effective prescribing. Disclosure R.J. Nock: None. J.R. Maxwell: Other; JRM has served on advisory boards for Abbvie, Pfizer, BMS and Lilly and has received speaking honoraria from Pfizer, BMS, Novartis and Lilly.

Background/Aims Juvenile idiopathic arthritis (JIA) is a heterogenous, childhood-onset condition persisting into adulthood in over 50% of people. Recognition of JIA-specific features is poor in adult services, there are no validated disease activity scores for adults with JIA and specialist adult JIA clinics are rare; this leads to under-treatment of adults with JIA. Sheffield Teaching Hospitals (STH) has a mature transition service and well-established young adult clinic (YAC) for 16-25 year olds and older adults with JIA. Here, we evaluate the proportion of our adult rheumatology workload attributable to JIA, the prevalence of JIA subtypes and therapies utilised. Methods Outpatient attendances in STH rheumatology are coded by diagnosis. The evaluation period was 1.12.2018 to 27.2.2020. We evaluated the number and characteristics of patients in the JIA cohort, producing a database from coded diagnoses and patient records, and analysed this using Microsoft Excel. Local permission was granted. Results 11,520 patients were seen in adult rheumatology in the evaluation period; 9,422 had a coded diagnosis of which 4,915 (52%) had inflammatory arthritis (IA). Assuming a proportional number of the 2,098 non-coded patients had IA (1,090), the adult IA cohort is estimated at 6,005. 304 patients (aged 17-72) with JIA were seen in adult rheumatology, accounting for 5% of the adult IA cohort. 280 (92%) were in the YAC, and 24 (8%) in general rheumatology. 31 (10%) patients had evidence of uveitis. The commonest subtypes of JIA were: 75 polyarticular (25%), 38 enthesitis related (13%) and 37 extended oligoarticular (12%). 64 (21%) patients had no subtype specified. Of the 233 (77%) JIA patients ever treated with methotrexate, 132 (57%) had discontinued due to inefficacy or adverse effects. 175 (58%) patients were on biologic treatment: the commonest therapies were adalimumab (40%, 70 patients) and etanercept (27%, 47 patients). There is evidence of diagnostic relabelling from JIA to other IA to access biologics not approved by NICE. Conclusion This evaluation uses real-world data, with some data loss due to absent coding, but shows JIA is a small proportion of adult rheumatology. This is a complex group with high biologic use, poor methotrexate tolerance and heterogenous disease phenotypes. Young adults experience specific challenges in adult services and require developmentally appropriate care, for which best evidence confirms young adult clinics are ideal. The majority of people with JIA are in a dedicated young adult service at STH. Biologics are used within NICE guidance, except for a minority where JIA is relabelled as IA to access additional biologics or due to independent funding requests. NICE guidance for JIA is outdated and restrictive. JIA is an adult disease in > 50% and requires specialist services, further research to elucidate validated adult disease activity scores and wider education amongst adult rheumatologists. Disclosure R.J. Nock: None. J.R. Maxwell: Other; JRM has served on advisory boards for Abbvie, Pfizer, BMS and Lilly and has received speaking honoraria from Pfizer, BMS, Novartis and Lilly. R.S. Tattersall: Other; RST has received speaker fees and educational grants to attend meetings from UCB, AbbVie, Pfizer and Janssen.

Background Rheumatoid arthritis (RA) is an inflammatory autoimmune disease that causes chronic synovitis, resulting in progressive joint destruction and functional disability and affects approximately 400,000 people in the UK. This real-world study aimed to describe the characteristics, treatment patterns and clinical outcomes of patients who received abatacept in UK clinical practice. Methods This was a multi-centre, retrospective, observational study of patients with RA treated with abatacept at four UK centres between 01 January 2013 and 31 December 2017. Data were collected from medical records of each patient from the index date (date of first bDMARD initiation) until the most recent visit, death or end of study (31 December 2017). Results In total, 213 patients were included in the study. Patients received up to eight lines of therapy (LOTs). Treatment with abatacept, or any other bDMARD, was associated with reductions in DAS28-ESR and DAS28-CRP scores at 6 and 12 months. The distribution of EULAR responses (good/moderate/no response) tended to be more favourable for patients when receiving abatacept than when receiving other bDMARDs (22.8%/41.3%/35.9% versus 16.6%/41.4%/42.1% at 6 months, and 27.9%/36.1%/36.1% versus 21.2%/34.5%/44.2% at 12 months). Patients receiving abatacept at LOT1 (n = 68) spent significantly longer on treatment compared with patients receiving other bDMARDs (53.4 vs. 17.4 months; p Conclusions RA patients who received bDMARDs, including abatacept, experienced reduced disease activity. When receiving abatacept as first or second line of therapy, patients persisted with treatment significantly longer than those receiving other bDMARDs.

Background Giant cell arteritis (GCA) usually affects the temporal arteries but can result in systemic vasculitis that can be seen on Positron Emission Tomography-Computed Tomography (PET-CT). Currently PET-CT is not used first line to diagnose cranial-GCA and temporal artery biopsy (TAB) remains the most common investigation to assess for this. There have been few studies performed to assess the use of PET-CT as an initial diagnostic tool in cranial-GCA. One study performed PET-CT for suspected GCA in their cohort of 64 patients. They found, when compared with TAB, global GCA assessment by PET-CT had a sensitivity of 92%, specificity of 85%, positive predictive value of 61% and negative predictive value of 98%. They concluded PET-CT had good diagnostic accuracy when compared with TAB and can be used as a first-line test to assess for GCA and rule out lower-risk GCA. Another study used PET-CT in steroid-naïve patients and also showed a high accuracy (sensitivity 64% and specificity of 100%) in diagnosing cranial artery inflammation. Methods We present two cases where the patient had symptoms of headache, constitutional symptoms and raised inflammatory markers, however PET-CT did not suggest GCA. The patients were subsequently re-referred later with ongoing symptoms and TAB confirmed GCA. Results Case 1: A 71-year-old woman presented with a one-month history of intermittent right sided headache and rigors. Her inflammatory markers were elevated (CRP of 115mg/L and ESR of 57mm/hr). Suspecting GCA, prednisolone 30mg od was commenced. Upon rheumatology review, it was felt her symptoms were atypical for GCA. Prednisolone was discontinued, and a PET-CT scan was arranged. This was performed ten days later and did not show any features of vasculitis. Six weeks later, the patient presented to ophthalmology reporting visual aura, ongoing headache with elevated inflammatory markers. Prednisolone 60mg od was commenced and a TAB was arranged. This was reported as partially treated GCA. Case 2: A 73-year-old gentleman had a prolonged admission for pyrexia of unknown origin. Headache was present throughout admission and rheumatology opinion was sought. A PET-CT did not show vasculitis. The patient was discharged when pyrexia improved however his inflammatory markers remained consistently high (CRP of 82mg/L and ESR 106mm/hr). One-month post-discharge, the patients GP contacted rheumatology concerned about ongoing headache and scalp tenderness. Prednisolone 40mg od was commenced and a TAB was arranged which reported features consistent with GCA. Both patients responded well to steroids. Conclusion As demonstrated, patients with biopsy proven GCA do not always exhibit vasculitis on imaging. A negative PET-CT did not reliably exclude GCA in our patients suggesting its use as a diagnostic investigation for GCA needs to be approached with caution. A TAB should also be performed when there is ongoing suspicion of GCA. Disclosures S. Khalid None. J. Maxwell Honoraria; BMS, Pfizer, Lilly, Abbvie. Other; Talks, BMS, Pfizer, Lilly, Abbvie.

Background Interstitial lung disease (ILD) is a serious extra-articular manifestation of rheumatoid arthritis (RA). Risk factors include smoking, the presence of rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibodies (CCP). Pulmonary function tests (PFT) show reduced carbon monoxide diffusion capacity (DLCO) early and reduced forced vital capacity (FVC) later in disease. HRCT is the gold standard diagnostic test while chest X-ray (CXR) has low sensitivity. PFT are routinely performed in the majority of RA patients at baseline at our tertiary centre. The aim of this study was to evaluate the frequency of abnormal PFT, specificity for ILD and influence on subsequent decision-making in patients newly diagnosed with RA. Methods A retrospective analysis was undertaken of patients with a new diagnosis of RA between January 2016 and December 2017. Patients meeting the ACR (2010) criteria for RA, with baseline PFT data available were included. Clinic letters and the hospital electronic records were used to obtain the data. Results 139 patients were included in the data analysis (Table 1). 23 patients had DLCO Conclusion This evaluation suggests baseline PFT are more sensitive than baseline CXR in detecting ILD but that a DLCO Disclosures A. Haque None. R. Kilding None. R. Smith None. S. Khalid None. R. Sandler None. M. Cox None. T. Hendry None. A. Flores-martin None. K. Lindop None. J. Maxwell None.

Background The mainstay of treatment for large vessel vasculitis is glucocorticoids. Immuno-suppressants, including mycophenolate mofetil (MMF) and methotrexate (MTX) are used as steroid-sparing agents. 1 A previous study at our centre showed MMF to have a steroid sparing effect in 97% of patients and to reduce C-reactive protein (CRP) in 80%. 2 Objectives This study was undertaken to compare the efficacy of MMF or MTX combined with prednisolone or prednisolone alone in the treatment of large vessel vasculitis. Methods Patients with large vessel vasculitis (LVV) confirmed on positron emission tomography (PET) scan and those meeting ACR criteria for a diagnosis of giant cell arteritis (GCA), treated with prednisolone alone, prednisolone with MMF or prednisolone with MTX started within 3 months of prednisolone being commenced and with a minimum follow up of 24 months were included in a retrospective single centre study. CRP and prednisolone doses were recorded at baseline, after 3, 6, 9, 12, 18 and 24 months of treatment and area under the curve (AOC) calculated for CRP and prednisolone doses. Median AOC prednisolone dose for patients treated with MMF or MTX was then compared with that of patients treated with prednisolone alone. A quantile regression model was also constructed to compare prednisolone dose between the 3 treatment groups, adjusted for CRP. StataCorp. 2013. Stata Statistical Software: Release 13 . College Station, TX: StataCorp LP was used for all statistical calculations. Results 65 patients were included in the study, 41 with GCA and 24 LVV. 49 were female and 16 male. Mean age at diagnosis was 68; range 21 to 87. 37 patients were treated with prednisolone alone; 35 had GCA and 2 LVV. 20 were treated with MMF and prednisolone; 4 with GCA and 16 LVV. 8 were treated with MTX and prednisolone; 2 had GCA and 6 LVV. The AOC for prednisolone and CRP were not normally distributed across the cohort, and non-parametric methods were therefore used for comparisons. Median AOC prednisolone dose for the prednisolone only group was 68.0, (interquartile range (IQR) 17.7, n=37), for the MMF treated group 70.8 (IQR 28.7, n=20) and for the MTX treated group 67.8 (IQR 20.4 n=8). Median AOC CRP was highest in the group treated with prednisolone alone (58.9, IQR 34.5) compared to MMF (43.8, IQR 26.5) and MTX (49.3 IQR 67.5) but there were no statistical differences between median AOC prednisolone dose or CRP in either the unadjusted or regression models. Conclusions No significant difference was shown between the groups. MMF is as effective as MTX and prednisolone alone in the treatment of LVV. However, there are limitations to the study. The patient group was small. There was no randomisation to treatment group; treatment choice was based on clinician preference. There was potential bias in that patients perceived to be more difficult to treat may have been given MMF or MTX in addition to prednisolone, and there was a higher proportion of patients with LVV compared to GCA in the MMF and MTX treated groups. References [1] Mukhtyar C, et al. EULAR recommendations for the management of large vessel vasculitis. Ann Rheum Dis2009:68:318–23. [2] Smith R et al.Is Mycophenolate Mofetil Effective in the Treatment of Large Vessel Vasculitis? Rheumatology 54, Issue suppl_1, 1 April 2015, Pages i194. Disclosure of Interest None declared

Background Tocilizumab (TCZ) is a humanised anti interleukin-6 receptor antibody licensed for use for the treatment of moderate to severe Rheumatoid Arthritis (RA) as monotherapy or in combination with methotrexate (MTX). Objectives To describe the use of TCZ for RA in a large UK teaching centre and examine reasons for treatment discontinuation. Methods A retrospective case note review of all adult patients receiving TCZ either alone or in combination with DMARDS, for the treatment of RA between April 2009 and January 2017 in Sheffield, UK. Results 132 patients received TCZ for RA. 71% were female. 61% were CCP positive. Mean disease duration was 15.6 years (range 1.5–43). 46 (34.6%) received TCZ as monotherapy, 55 (42.1%) in combination with MTX and 31 (23.3%) other DMARDS. 23% of patients received concomitant oral prednisolone. Median duration of TCZ treatment was 27 months across the whole cohort, and 19 months in those who discontinued treatment. Overall 44 (33%) patients discontinued TCZ; 5 due to primary and 10 secondary inefficacy, 27 patients due to adverse events (8 recurrent infection, 5 abnormal LFT, 4 malignancy, 3 rash, 7 other including 1 death whilst on treatment). A logistic regression model, including gender, smoking status, disease duration, DMARD use, steroid treatment and number of prior biologics was constructed to examine association with treatment discontinuation. Of these factors, disease duration (p=0.05) and number of previous biologics (p=0.09) were weakly associated with persistence of TCZ and in particular there was no association of concomitant DMARD or steroid treatment with discontinuation either due to lack of efficacy or adverse events. Table 1 demonstrates the proportion of patients stopping treatment, and treatment duration according to previous biologic treatment received. We have not seen any cases of infusion reaction, diverticular perforation or reactivation of tuberculosis. Conclusions Our real world data on the use of TCZ in the treatment of adult patients with RA is consistent with clinical trial data for efficacy and safety and is similar to other biological drugs used in the treatment of RA. We have seen a relatively low rate of withdrawal due to primary and secondary treatment failure. Disclosure of Interest None declared

Background Polymorphisms of the peptidylarginine deiminase type 4 ( PADI4 ) gene confer susceptibility to rheumatoid arthritis (RA) in East Asian people. However, studies in European populations have produced conflicting results. This study explored the association of the PADI4 genotype with RA in a large UK Caucasian population. Methods The PADI4_94 (rs2240340) single nucleotide polymorphism (SNP) was directly genotyped in a cohort of unrelated UK Caucasian patients with RA (n=3732) and population controls (n=3039). Imputed data from the Wellcome Trust Case Control Consortium (WTCCC) was used to investigate the association of PADI4_94 with RA in an independent group of RA cases (n=1859) and controls (n=10 599). A further 56 SNPs spanning the PADI4 gene were investigated for association with RA using data from the WTCCC study. Results The PADI4_94 genotype was not associated with RA in either the present cohort or the WTCCC cohort. Combined analysis of all the cases of RA (n=5591) and controls (n=13 638) gave an overall OR of 1.01 (95% CI 0.96 to 1.05, p=0.72). No association with anti-CCP antibodies and no interaction with either shared epitope or PTPN22 was detected. No evidence for association with RA was identified for any of the PADI4 SNPs investigated. Meta-analysis of previously published studies and our data confirmed no significant association between the PADI4_94 genotype and RA in people of European descent (OR 1.06, 95% CI 0.99 to 1.13, p=0.12). Conclusion In the largest study performed to date, the PADI4 genotype was not a significant risk factor for RA in people of European ancestry, in contrast to Asian populations.

Objective.Recent studies have identified 6q23 as an important susceptibility locus for rheumatoid arthritis (RA), with risk alleles at 3 single-nucleotide polymorphisms combining to give an effect size greater than that of these markers individually. We investigated whether these polymorphisms are also associated with disease severity measured by radiological damage.Methods.We studied 927 patients from a cross-sectional RA cohort. Median Larsen scores (LS) read from radiographs taken at study entry were compared by genotype at rs6920220, rs13207033, and rs5029937 according to a dominant model using negative binomial regression with stratification for autoantibody status.Results.Median LS was associated with genotype at rs6920220 [LS 31 GG vs 36 GA/AA (p = 0.02) in cyclic citrullinated peptide+ (CCP) RA] and rs13020220 [LS 37 GG vs 29 GA/AA (p = 0.02) in CCP+ RA] only in autoantibody-positive RA, with no association at rs5029937. Association was stronger for these markers in combination [LS 28 vs 42 for lowest vs highest risk genotype combination in rheumatoid factor positivity (p = 0.007), LS 28 vs 37 for anti-CCP+ (p = 0.01)].Conclusion.Established RA risk markers at 6q23 are associated also with radiographic severity in autoantibody-positive RA; as for susceptibility, the association for these markers in combination is stronger than that for markers alone.

The National Lung Screening Trial (NLST) is a randomized multicenter study comparing low-dose helical computed tomography (CT) with chest radiography in the screening of older current and former heavy smokers for early detection of lung cancer, which is the leading cause of cancer-related death in the United States. Five-year survival rates approach 70% with surgical resection of stage IA disease; however, more than 75% of individuals have incurable locally advanced or metastatic disease, the latter having a 5-year survival of less than 5%. It is plausible that treatment should be more effective and the likelihood of death decreased if asymptomatic lung cancer is detected through screening early enough in its preclinical phase. For these reasons, there is intense interest and intuitive appeal in lung cancer screening with low-dose CT. The use of survival as the determinant of screening effectiveness is, however, confounded by the well-described biases of lead time, length, and overdiagnosis. Despite previous attempts, no test has been shown to reduce lung cancer mortality, an endpoint that circumvents screening biases and provides a definitive measure of benefit when assessed in a randomized controlled trial that enables comparison of mortality rates between screened individuals and a control group that does not undergo the screening intervention of interest. The NLST is such a trial. The rationale for and design of the NLST are presented.

This review focuses on the contribution of genetic markers to the severity of radiological damage in rheumatoid arthritis (RA). Currently available biomarkers of more severe disease include elevated erythrocyte sedimentation rates or C-reactive protein levels and rheumatoid factor (RF) or anticyclic citrullinated protein antibodies positivity; however, these biomarkers explain a relatively modest proportion of the variance in radiological damage. An important role of genetic factors on RA severity has recently emerged but studies to date have generally been of low statistical power and many have not been replicated. Genetic markers have a number of advantages over conventional biomarkers; genotypes are stable, measurable at disease onset, remain unchanged by treatment and are amenable to high-throughput assays. The recent advances in genome-wide genetic analysis should lead to a more comprehensive understanding of RA severity genes. This knowledge could be used, along with existing biomarkers, to therapeutically target subjects at risk of poor radiological outcome.

Objectives To investigate the association between genotype at the soluble interleukin 6 receptor (sIL-6R) A358C single nucleotide polymorphism (SNP, rs8192284), previously reported to correlate with soluble receptor levels, and response to anti-TNF therapy in subjects with RA. Methods In a large cohort of Caucasian RA patients treated with anti-TNF medications (total, n = 1050; etanercept, n = 455; infliximab, n = 450; and adalimumab, n = 142), the sIL-6R A358C polymorphism was genotyped using a Taqman 5'-allelic discrimination assay. Linear regression analysis adjusted for baseline 28 joint disease activity score (DAS28), baseline HAQ score, gender and use of concurrent DMARDs was used to assess the association of genotype at this polymorphism with response to anti-TNF therapy, defined by change in DAS28 after 6 months of treatment. Analyses were performed in the entire cohort, and also stratified by an anti-TNF agent. Additional analysis according to the EULAR response criteria was also performed, with the chi-squared test used to compare genotype groups. Results No association between genotype at sIL-6R A358C and response to anti-TNF treatment was detected either in the cohort as a whole or after stratification by anti-TNF agent, in either the linear regression analysis or with response segregated according to EULAR criteria. Conclusions This study shows that genotype at the functional sIL-6R A358C SNP is not associated with response to anti-TNF treatment in patients with RA.

Periods in Earth history characterized by extensive organic carbon deposition, so-called oceanic anoxic events (OAEs), are the subject of considerable scrutiny. Insight into the extent of anoxic conditions in the water column has been provided by the reported occurrence of derivatives of isorenieratene, a carotenoid found only in green sulphur bacteria and thus indicative of photic-zone euxinia (i.e. a water column containing free H 2 S), in North Atlantic deep-sea sediments deposited during the Cenomanian–Turonian boundary OAE2 (Bonarelli Event). In this study, we have used the distributions of chlorophyll and bacteriochlorophyll degradation products, maleimides (1- H -pyrrole-2,5-diones) and high molecular weight porphyrins, to examine further the Cenomanian–Turonian boundary OAE2 as well as other OAEs of the early Toarcian (Posidonienschiefer Event) and early Aptian (Selli Event). In particular, methyl isobutyl (Me, i -Bu) maleimide, on structural grounds, appears to be diagnostic of green sulphur bacteria. This compound occurs in five of seven examined marls that record the early Toarcian OAE (Marche–Umbria, Italy), further expanding the geographical range of Toarcian sediments where evidence for photic-zone euxinic conditions has been found. Me, i -Bu maleimide occurs in three of six black shales spanning the Livello Selli (Marche–Umbria, Italy), the type locality for the Aptian OAE1a, providing the first evidence for photic-zone euxinic conditions during this event. With respect to the Cenomanian–Turonian OAE, maleimide evidence for photic-zone euxinic conditions was found in all the North Atlantic sites investigated, including those characterized by relatively organic-lean sediments, several Tethyan sites and one site off western Australia. These data indicate that euxinic conditions were common in the water column during Mesozoic oceanic anoxic events.

Variations in nitrogen isotopic composition (δ15N) and total chlorin accumulation rate (AR) are employed as proxies to reconstruct oceanic nitrate inventory, the balance between denitrification and N fixation, and paleoproductivity in a rapidly accumulating sediment drift deposit beneath the Western Pacific Warm Pool for the last 145 Kyr. Subsurface and deep waters of the northern South China Sea (SCS) are sourced from the shallow Kuroshio Current (KC) and Pacific Intermediate Water, respectively. Their relative importance in determining sedimentary δ15N and paleoproductivity have been altered by changes in equatorial circulation, summer- and winter-monsoon intensity and relative sea level. The location and basin configuration of the marginal SCS renders it especially sensitive to such changes. Assuming complete annual nitrate utilization, low δ15N values during glacial stages are interpreted as a reflection of reduced remote denitrification in the Eastern Tropical North Pacific (ETNP) source waters, while much of marine isotope stage (MIS) 3 and the last interglacial were characterized by high denitrification. However, intervals of anomalously low δ15N values are interpreted as reflecting the contribution from regional N fixation in West Pacific surface waters, transmitted to the site by the shallow KC. Unusually, the Holocene is characterized by declining δ15N values and an inverse correlation with organic matter content since ca. 8.2 Ka. Millennial-scale variations during MIS 3 indicate higher frequency variations in both ETNP denitrification and local N fixation, which may be coherent with a hemispheric response to Dansgaard–Oeschger events recorded at high latitudes. For much of the last 145 Kyr, paleoproductivity was decoupled from δ15N, and instead seems to reflect the extent of the global nitrate inventory stimulated by elevated dust fertilization, and regional mixed-layer deepening associated with the relative intensity of the SE Asian winter monsoon. Despite evaluation of possible conflicting influences on the record of each proxy, we interpret our data as clear evidence of glacial/interglacial changes in marine nutrient inventory across the whole of the North Pacific, with a corresponding biogeochemical response and important implications for global CO2 drawdown via an invigorated biological pump. The relative importance of local, regional and global contributions to our records appears to be strongly modulated by relative sea level, controlling trans- and extra-basinal circulation in the SCS.

Previous studies of maleimides (1-H-pyrrole-2,5-diones), oxidative degradation products of chlorophylls and bacteriochlorophylls, and aromatic compounds derived from certain carotenoids (i.e., isorenieratene) indicate that photic zone euxinia (PZE) occurred at least intermittently during deposition of the German Kupferschiefer (Late Permian). However, that work was restricted to a stratigraphic profile through the Kupferschiefer of the Lower Rhine Basin, a shallow lagoon setting, and it was not established if photic zone euxinia prevailed in the larger and deeper basins of the Permian Zechstein Sea. Here, we present maleimide and porphyrin distributions in sediments from the Northern and Southern Permian basins. In samples from both basins, methyl,iso-butyl (Me,i-Bu) maleimide was recovered from the free extractable fraction and upon oxidation of vanadyl and nickel alkyl porphyrins. On structural grounds, Me,i-Bu maleimide derives ultimately from bacteriochlorophyll (bchl) c, d, or e and is thus indicative of the presence of green sulfur bacteria in the ancient Zechstein Sea. Consistent with this, C34 and C35 porphyrins apparently derived from bacteriochlorophyll d were also identified in the Northern Basin samples. Because green sulfur bacteria require both light and free H2S, these results indicate that photic zone euxinia occurred at least periodically during the early history of the Zechstein Sea.

To investigate possible reasons for the discrepancy between the abundance of 4-methyl components in free sterols and steryl chlorin esters (SCEs) which is commonly observed in sediments, experiments in which the copepod Calanus helgolandicus grazed on the dinoflagellates Prorocentrum micans and Alexandrium tamarense were carried out. With P. micans all the algal sterols were esterified as SCEs in the faecal pellets, but there was clear discrimination against the uptake of 4-Me sterols. This discrimination was also evident with A. tamarense. To investigate changes in the faecal pellet SCE and the free sterol distributions during pellet ageing in the P. micans experiment, portions were allowed to stand for up to 29 days in seawater in the dark. Although degradation of SCEs occurred, their esterified sterol distribution remained unchanged. The free sterols were degraded more rapidly than the SCEs and changes in the distribution were observed. This provides further laboratory evidence that sedimentary SCE sterols are more robust markers of phytoplankton communities than the corresponding free sterol distributions. Comparison of the SCE abundance in sterilised and unsterilised pellets indicated that the degradation was a result of microbial activity.

The production of steryl chlorin esters (SCEs) of both pyrophaeophorbide a and pyrophaeophorbide b has been demonstrated in a laboratory experiment in which the copepod Calanus helgolandicus grazed on the prasinophyte Tetraselmis suecica. Both algal sterols were converted into SCEs a and b with equal efficiency, indicating that in this case the SCE sterols were directly representative of the substrate. The sterols of the animal were also converted to SCEs, although with some change in the distribution as a result of cholesterol demand by the copepod. The results show that during herbivory chlorophyll b undergoes the same biotransformation to SCEs as reported for chlorophyll a and predict that SCEs b should occur in sediments beneath a phytoplankton population containing a significant contribution of chlorophyll b.

Steryl esters of the chlorophyll a transformation product pyrophaeophorbide a (SCEs), were formed when the copepod Calanus helgolandicus was allowed to graze on the marine diatom Thalassiosira weissflogii , confirming an earlier preliminary experiment. All of the animal and algal sterol components were found in the SCEs although there were distributional changes attributed to alteration prior to esterification to pyrophaeophorbide a , which resulted from utilisation by the copepod to produce cholesterol. This indicates that where there is insufficient cholesterol in the zooplankton diet in the natural environment, sedimentary SCE sterol distributions may not accurately reflect the original phytoplanktonic free sterol distribution. Although the concentration of SCEs dropped markedly as a result of pellet ageing, their abundance relative to the other major chlorins increased. This relative stability provides an explanation for a previous observation that SCEs in surface sediments are present in higher abundance than in the corresponding water column particulates and accounts for their significant abundance in the solvent extractable chlorins in sediments. Two novel products, tentatively proposed as the phytyl ester and the 24-methylcholesta-5,24(28)-dien-3β-yl ester of 13 2 -oxopyrophaeophorbide a were also observed in the pellets, although the widely occurring rearranged sedimentary chlorin 13 2 -hydroxychlorophyllone a (chlorophyllone) was only detected in aged pellets.

A method is described for the liquid chromatography/tandem mass spectrometry analysis of free base porphyrins, which allows the routine and rapid recognition of alkyl substituents in the components of complex natural mixtures. The method overcomes difficulties associated with probe tandem mass spectrometry or liquid chromatography/mass spectrometry which can arise from the numerous isobaric ions present in the spectra and the associated uncertainty in assigning fragment ions to individual components. MS and MS/MS spectra of synthetic and natural free base porphyrin standards are compared to identify spectral patterns which allow recognition of extended alkyl chains. In natural mixtures, the identification of cycloalkano porphyrins with such chains is based on comparison of product ion spectra of a series of C31–C35 standards and the presence of diagnostic ions which can be attributed to losses associated with >C2 alkyl chains. Liquid chromatography/tandem mass spectrometry analysis of a free base porphyrin mixture from Serpiano oil shale is carried out to obtain MS/MS spectra of palaeoenvironmentally significant minor components. The results reveal the presence of cycloalkano porphyrins with >C2 substituents in the shale, suggesting the occurrence of photic zone anoxia in the original depositional setting. Copyright © 1999 John Wiley & Sons, Ltd.

A multi-user integrated suite of instruments designed to optimize the search for evidence of life on Mars is described. The package includes: • ∗ Surface inspection and surface environment analysis to identify the potential Mars landing sites, to inspect the surface geology and mineralogy, to search for visible surficial microbial macrofossils, to study the surface radiation budget and surface oxidation processes, to search for niches for extant life. • ∗ Analysis of surface and subsurface minerals and organics to characterize the surface mineralogy, to analyse the surface and subsurface oxidants, to analyze the mineralogy of subsurface aliquots, to analyze the organics present in the subsurface aliquots (elemental and molecular composition, isotopes, chirality). • ∗ Macroscopic and microscopic inspection of subsurface aliquots to search for life's indicators (paleontological, biological, mineralogical) and to characterize the mineralogy of the subsurface aliquots. The study is led by ESA Manned Spaceflight and Microgravity Directorate.

Stepwise chemical degradation involving cleavage of ester bonds (KOH/MeOH), sulfide and remaining ester bonds (Li/EtNH2), ether bonds (HI/LiAlH4) and sub-units linked to aromatic moieties (RuO4) has been carried out on the kerogens of two immature sulfur-rich marls (IV-1.4 and 1.8, TOC ca. 1.5%) from evaporitic cycle IV of the Gesosso-solfifera Formation (Messinian, Vena del Gesso, Italy). Up to 80% of the organic matter was converted to solvent-soluble material, with the greatest proportion released by Li/EtNH2. The majority by far of the extracts comprises polar macromolecular material which is thought to correspond to high molecular weight sub-units of the kerogen. Quantification of the small amounts (

Messinian marls from evaporitic cycle IV of the Gessoso-solfifera formation (Italy) are known to contain in high abundance the diaromatic carotenoid isorenieratene of green sulfur bacterial (Chlorobiaceae) origin along with a second diaromatic carotenoid. The previous tentative assignment of the latter as a cis diastereomer of isorenieratene has now been confirmed; this indicates that double bond isomerization occurs during early diagenesis and provides further evidence for the pathway proposed previously to link isorenieratene to a number of aromatic isoprenoid hydrocarbon biomarkers. Stable carbon isotopic data confirm the Chlorobiaceae origin of the intact all-trans isorenieratene isomer and indicate that the isomerization is accompanied by little or no kinetic isotope effect. Comparison of the δ13C values of each of the isolated carotenoids (measured as isorenieratane after hydrogenation) with those of their sulfide-bound counterpart in the polar fraction of the extracts (also measured as isorenieratane) indicates that sulfurization resulted in little depletion in 13C.

3 β -Hydroxy-5 α -androstan-17-one (epiandrosterone), 5 α -androstan-3,17-dione, 3 α -hydroxy-5 α -androstan-17-one (androsterone), 5 α -androstan-3 β ,17 β -diol and 5 α -androstan-3 α ,17 β -diol have been identified in the solvent soluble fraction of peat from Bolton Fell Moss (Cumbria, U.K.). The structures and δ 13 C values of these androstane derivatives indicate a diagenetic origin in sterols also present in the peat and provide the first evidence that cleavage of the C-17 side-chain can occur during early diagenesis, microbial oxidation being the most likely mechanism.

To investigate the effect of bacterial diagenesis on the distributions of algal lipids, the marine haptophyte Emiliania huxleyi was incubated with estuarine sediment slurries under defined conditions (oxic, sulfate reducing and methanogenic). Rapid initial degradation of lipids corresponded to increased bacterial populations, both of which subsequently declined. Under oxic conditions the algal C31 dienes were rapidly and completely degraded within 178 days. Extensive degradation of the characteristic C37 methyl alkenones occurred under all conditions (up to 85% under oxic conditions); however, the U37K′ index remained essentially constant, except for a slight increase at the longest oxic incubation time. Under anoxic conditions the alkyl alkenoates were preferentially degraded relative to the alkenones and changes in the AA36 index occurred. These results demonstrate that lipids are part of the “labile” organic matter; however, they were generally degraded at multiple rates which slowed during incubation, resulting in their partial preservation. Hence, laboratory experiments conducted over only short periods cannot predict the preservation potential of lipid components. Furthermore, preservation differed between sulfate reducing and methanogenic conditions, so the roles of anaerobic processes need to be considered individually with regard to oxic vs. anoxic preservation.

Pyrophaeoporphyrins c 1 and c 2 ( I a, b ), transformation products of chlorophylls c 1 and c 2 ( II a, b ) occur as minor pigments in the surface sediment (0–5 cm) of Priest Pot, a small eutrophic lake (Cumbria, U.K.) and in the products from feeding the diatom Thalassiosira weissflogii to the copepod Calanus helgolandicus . These findings, based on comparisons with standards prepared from the chlorophylls c 1 and c 2 , indicate that enzymatic removal of the C-13 2 carbomethoxy substituent, a prerequisite for the diagenetic transformation pathway of the chlorophylls c to a number of sedimentary alkyl porphyrins, occurs mainly in the water column as a result of zooplankton herbivory.

The sterol distributions in the steryl chlorin esters (SCEs) from three marine and two lacustrine sediments have been compared with the free sterols and known water column sterol distributions. The comparison provides further evidence that the SCE sterol distributions are more representative of the original phytoplanktonic sterol distribution than are the free sterol distributions. This is most clearly seen in the relative abundance of C 26 sterols and 4-methyl sterols, and in the stanol/stenol ratios. It appears that in general the SCE sterols are less susceptible to selective biodegradation than the free sterols.

Speciation of iron and sulfur species was determined for two recent sediments (La Trinitat and Lake Cisó) which were deposited in environments with a high biological productivity and sulfate-reducing activity. In sediments from calcite ponds of La Trinitat an excess of reactive iron species (iron monosulfides, iron hydroxides) results in a depletion of reactive sulfur which is accompanied by a virtual absence of organo-sulfur compounds, both in low (LMW) and high molecular-weight (HMW) fractions. Small amounts of phytanyl and highly branched isoprenoid (HBI) thiophenes in the extract demonstrate that these molecules exhibit a higher reactivity towards reduced sulfur species as compared to detrital iron. Euxinic sediments from Lake Cisó are characterised by an excess of reduced sulfur species which can rapidly trap reactive iron. High concentrations of H2S results in the formation of organo-sulfur compounds which were encountered in both LMW and HMW fractions. The major part of the organic sulfur is bound to the carbohydrate portion of woody tissues, whose presence was revealed by a specific alkylthiophene distribution in the flash pyrolysate and by Li/EtNH2 desulfurisation of the kerogen which resulted in the solubilisation of the sulfur-enriched hemicellulose fraction. Relatively high amounts of sulfurised C25 HBI compounds in the sediment extract of Lake Cisó reflect the incorporation of sulfur into algal derived organic matter upon early diagenesis. The combined approach of the speciation of iron and sulfur species and the molecular analysis of sedimentary fractions demonstrates that abiotic sulfur binding to organic matter occurs at the earliest stages of diagenesis under specific depositional conditions (anoxic, stratified water column) in which an excess of reduced sulfur species relative to the amount of reactive iron is a controlling factor.

Biomarker distributions based on GC and GC-MS data supplemented by stable carbon isotopic compositions based on irm (isotope ratio monitoring) GC-MS data have been used to investigate changes in depositional conditions in a number of samples from a 2 m core (Rheinberger Heide) covering the entire deposition of the Permian Kupferschiefer (Lower Rhine Basin, northwest Germany). Compound classes investigated are aliphatic and aromatic hydrocarbons and maleimides (1H-pyrrole-2,5-diones). The core has been previously divided into four sections: TI, TIIA, TIIB and TIII based on lithology. The biomarker distributions and the δ13C values of components indicate contributions from cyanobacteria, algae, green sulphur bacteria and higher plants (minor) throughout Kupferschiefer deposition. All of the phytoplanktonic components show 13C enrichment in the lowest section, suggesting a greater productivity. The occurrence of components derived from green sulphur bacteria (Chlorobiaceae) indicates that the entire deposition was characterised by periods of photic zone anoxia. Such conditions were rapidly established after the initial transgression of the Zechstein Sea and may have been productivity-driven, but were less prevalent during deposition of the upper core sections.

The so-called Heinrich layers, found in North Atlantic sediments, have been attributed to quasi-periodic discharges of armadas of icebergs originating from the Laurentide ice sheet. Using the distribution of biomarkers in a sediment core (BOFS 5K) we have attempted to provide more information about their origin and the effect of the Heinrich events on oceanic circulation and the climatic system. Estimates of sea surface temperature changes, via U3K7 measurements, show that the surface ocean underwent significant cooling during the events, probably as a result of incoming iceberg meltwater. The low sea temperatures and the rapid variation in the accumulation of chlorophyll-derived pigments suggest that the events provoked a major change in oceanographic conditions, which may have affected the thermohaline circulation in the Atlantic Ocean. Within the most recent layers we have also found vanadyl alkyl porphyrins and aryl isoprenoid hydrocarbons, diagenetic products of photosynthetic pig- ments (chlorophylls and carotenoids, respectively). These components are not expected to occur in late Quaternary sediments, so their presence demonstrates a contribution to the layers of ancient, organic rich sedimentary material of continental origin. The presence of vanadyl porphyrins and absence of their nickel counterparts, and the distributional features of the aryl isoprenoids (e.g., presence of the C40 reduced carotenoid isorenieratane of green sulphur bacterial origin) indicate the existence of anoxic conditions in the photic zone of a marine water column in the original depositional setting of the contributed ancient sediment. These results suggest that it should be possible, using a biomarker correla- tion approach, to determine the source area of the ancient sediment eroded by the icebergs. Copyright © 1997 Elsevier Science Ltd

A study of the distributions of free and S-bound biomarkers and their δ13C values in the extract of a bulk sample of the Permian Kupferschiefer from the Lower Rhine Basin has been carried out to provide a more detailed characterization of the biological inputs. The distributions and isotopic compositions of selected components released from nickel boride desulphurization have been compared with those of components in the free fraction. The free biomarkers occur in greater abundance than their S-bound counterparts. The distribution and carbon isotopic composition of both free and bound components in the extract indicate a major cyanobacterial and algal input. Likewise, the free and bound aromatic hydrocarbons contain components which reveal an origin from the carotenoids of Chlorobiaceae (green sulphur bacteria), providing molecular evidence for the occurrence of photic zone anoxia in the water column. Most of the components in the complex mixture of mono-, di-, tri- and tetra-aromatics in the free aromatic hydrocarbon fraction result from cyclization and aromatization reactions.

The (22 R )-30a,30b-dihomohopan-30b-yl and tetrahymanyl esters of pyrophaeophorbide a , chlorophyll a transformation products resulting from zooplankton herbivory, occur in an extract of surface sediment from Lake Valencia (Venezuela). The former was identified by HPLC-PDA-MS comparison with a standard and the latter after reduction of the extract and GC-MS analysis of the released alcohols.

Maleimides (1 H -pyrrole-2,5-diones), degradation products of photosynthetic tetrapyrrole pigments, have been found for the first time in the polar fraction of the solvent extracts of two marine sediments deposited in restricted basins: Kupferschiefer (Permian) and Serpiano shale (Mid-Triassic). GC and GC—MS analyses of the TBDMS ( tertiary -butyldimethylsilyl) derivatives show a simple component distribution, dominated by Me Et maleimide, mainly of planktonic origin; Me n -Pr and Me i -Bu maleimides, present in low abundance, are thought on structural grounds to be derived from the bacteriochlorophylls c, d , or e of Chlorobiaceae (anoxygenic green sulfur bacteria). This is confirmed for Kupferschiefer by isotope ratio monitoring (irm) GCMS which shows them to be enriched in 13 C as a result of their photosynthetic carbon assimilation, which takes place by the reversed tricarboxylic acid (TCA) cycle. The structurally more specific Me i -Bu maleimide is, however, slightly more enriched in 13 C than Me n -Pr maleimide, suggesting that the latter is derived in part from reduction of the C 3 -acid substituent at C-17 of phytoplanktonic chlorophyll. These results provide evidence for the existence in both depositional settings of microbial communities containing Chlorobiaceae. In turn, this indicates that there must have been periods when the water column was highly stratified and anoxia extended into the zone of light penetration.

Steryl chlorin esters (SCEs) were formed in laboratory feeding experiments when starved females of the copepod Calanus helgolandicus were allowed to graze on a culture of the diatom Thalassiosira weissflogii. They were found when the zooplankton had grazed for 48 hours and were also identified in fecal pellets subsequently left in seawater in the dark. The distribution contained the diatom sterols in approximately the same relative abundance as the free sterols in the substrate, as well as the most abundant copepod sterol, all esterified to the chlorophyll a degradation product, pyropheophorbide a. Hence, in studies aimed at using sedimentary SCE sterol distributions as indicators of phytoplankton community structure, cholesterol should not be considered since the cholesteryl ester of pyropheophorbide a was a significant component in the fecal pellet SCEs. The findings represent a step forward in unravelling the transformations undergone by chlorophyll a in aquatic environments, since the abundance and wide occurrence of sedimentary SCEs indicate that they are a significant preservational sink for the chlorophyll a biosynthesised in the photic zone.

Kerogens isolated from nine samples from a single marl bed of the Gessoso-solfifera formation in the Vena del Gesso basin (Upper Miocene, Italy) were treated with CrCl 2 and Li/EtNH 2 to remove inorganic and organic sulphur, respectively. The untreated and “desulphurized” (CrCl 2 and Li/EtNH 2 ) kerogens were qualitatively and quantitatively analyzed by flash pyrolysis-gas chromatography-mass spectrometry. Typically, significant variations in the relative contributions and abundances of n -alk-1-enes/ n -alkanes, alkylated pyrroles, thiophenes and supposedly S-bound moieties released as phytenes and sterenes were observed. The first series of products ( n -hydrocarbons) contributed relatively more to the pyrolyzates of the desulphurized kerogens, suggesting an enrichment of microalgal-derived aliphatic macromolecules. These marine micro-organisms are thought to belong in part to the class of Eustigmatophyceae. Alkylated pyrroles were barely detectable in the untreated kerogen pyrolyzates, whereas they contributed significantly to those from the treated kerogens. Similar treatment of a porphyrin, octaethylporphyrin, revealed that alkyl porphyrins are thermally too stable to be cleaved upon pyrolysis. However, Li/EtNH 2 treatment reduced the porphyrin standard, such that it could generate mainly monopyrroles upon pyrolysis. It is concluded that Li/EtNH 2 treatment reduced tetrapyrrole moieties bound to the desulphurized kerogen network.

Bacterial populations and activity were quantified at three sites in the Cascadia Margin accretionary wedge, off the West Canadian/American coast (ODP Leg 146). At two sites sediments contained gas hydrates, Site 889/890 had a discrete zone of hydrate approximately 10 m above a bottom simulating reflector (BSR) at 225 m below sea floor (mbsf) and Site 892 had disseminated hydrate in the upper 20 mbsf and a BSR at 74 mbsf. Site 888 was a control site without gas hydrates. The control site (888) and top approximately 90 mbsf of Site 889/890 had bacterial distributions similar to previous Pacific Ocean sites. In the upper approximately 30 m of Site 892, however, bacterial populations were much lower, suggesting inhibition by the high concentrations of H 2 S within the hydrate zone. Below this depth bacterial populations rose to concentrations consistent with other sites. The control site was dominated by SO 4 reduction and rates of CH 4 oxidation in the top 90 m were low (0.002–0.033 nmol cm −3 d −1 ). At Site 889/890 bacterial populations and activity were stimulated in the discrete hydrate zone. CH 4 oxidation rates increased in the middle of this zone to 134.5 nmol cm −3 d −1 (ca. 9 times the average rate at other depths), resulting in a significant (× 10) increase in the total bacterial population. The anaerobic process(es) responsible for this oxidation remain unclear, despite SO 4 -reducing bacteria, previously associated with CH 4 oxidation, also being stimulated in this zone. Fluid flux into accretionary wedge sediments may be an important process in providing electron acceptors to maintain these relatively high rates of CH 4 oxidation. This first microbiological study of gas hydrates indicates that bacterial processes are influenced by gas and fluid venting, and they play a major role in geochemical changes within these deep (> 200 mbsf) sediments.

The iron porphyrin fraction of Kupferschiefer, an organic-rich sedimentary rock deposited in the Zechstein Sea during the Permian (ca. 235Myr before present) contains three minor components characterised by 1 H NMR spectroscopy. The carbon skeletons correlate specifically with members of one series of the bacteriochlorophylls d of the Chlorobiaceae, which are obligate anaerobes. Their structures therefore reveal the occurrence of anoxic conditions extending up into the zone of light penetration in the water column of the original depositional setting in the Lower Rhine Basin.

A sensitive, semi-automated method has been developed for the rapid estimation of the total concentration of chlorophyll a transformation products (chlorins) in solvent extracts of aquatic sediments. The methodology utilizes a laboratory robot for sample extraction and work up and a high pressure liquid chromatography (HPLC) system operated under off-column conditions. Use of an on-line tuneable fluorescence detector allows measurement of total chlorin concentration at greater sensitivity than conventional u.v./vis spectrophotometric detection, and allows reproducible results to be obtained from smaller sediment samples. This is relevant to palaeoceanographic studies at high stratigraphic resolution or where sample demand is high for other stratigraphic studies.

Kerogens of nine samples from a single marl bed of the Gessoso-solfifera Formation in the Vena del Gesso basin (Messinian, Italy) were qualitatively and quantitatively studied by analytical pyrolysis. Relationships between the nature of the pyrolysis products and the source organisms were determined. The high abundance of (i) algal-derived components (n-alkanes and n-alk-1-enes) and (ii) sulphur-containing and sulphur-bound products signifying a high degree of early diagenetic sulphurization were observed. Presence of photic zone anoxia during the deposition of these sediments was discussed via the presence of 1,2,3,4-tetramethylbenzene in the pyrolysates. Unusual distributions were found for three series of pyrolysis products (i.e. C13 and C14n-alkylated thiophenes and thiolanes and C12 and C13n-1,3-alkadienes were by far the major products of these series) in the pyrolysates of two samples corresponding to the middle of the cycle (samples 3 and 5) which also have the highest δ13CTOC values and the highest pyrolysis yields. Therefore, the contribution of organisms biosynthesizing resistant algal biopolymer was considered as much more important during the deposition of the sediments associated with samples 3 and 5. We finally proposed partial structural elements from which the specific low molecular weight compounds of samples 3 and 5 can be derived upon pyrolysis.

The porphyrins and carotenoids of marl horizons within the Messinian evaporitic cycles of the Vena del Gesso basin show variations in abundance and composition throughout a sequence of ten cycles. Significant variations are also apparent within individual marl horizons. The differences in pigment distribution reflect significant changes in the environmental conditions during sediment deposition. The presence of significant amounts of isorenieratene and co-occurrence of an alkyl porphyrin with a C 34 skeleton provide evidence for anoxic conditions extending into the photic zone of the palaeo-water column. Variations in the free pigment contents of the marls reflect a regressive trend both during deposition of an individual marl, and over the entire sequence.

Lithium in ethylamine ( Li EtNH 2 ) treatment has been carried out on sulphur-rich kerogens from 10 sub-samples of the cycle IV marl from the Vena del Gesso evaporitic sediments (Upper Miocene, Italy). The treatment releases, after chromatography of the resulting solvent extracts, up to 30% of the kerogen total organic carbon. The biomarkers released are dominated by components of algal origin. The concentrations of the aliphatic hydrocarbons obtained are of the same order of magnitude as the bound alkanes released upon desulphurization of polar fractions from organic extracts and show similar distributions. The presence of diaromatic isoprenoids derived from Chlorobiaceae indicates that photic zone anoxia occurred during the deposition of the cycle IV marl, such conditions being more prevalent at the middle of the section. Polar material makes up by far most of the organic material released and contains in particular alcohols and amides which may result from the cleavage of ester bonds present in these immature kerogens, the amides being secondary products formed by reaction with the EtNH2. In the case of the alcohols, however, these components could also arise from cleavage of sulphide-bound moieties.

An abundant chlorophyll a transformation product, found previously in a lake sediment (chlorophyllone a ) has been identified by LC-MS in sediments from five aquatic environents, both marine and lacustrine. Its previously unrecognized wide sedimentary occurrence and apparent post burial stability suggest it is an important preservational sink for the chlorophyll produced in the euphotic zone. It contains a seven-membered ring fused to a five-membered ring, and therefore provides further evidence for a transformation pathway linking chlorophyll a to a recently reported sedimentary bicycloalkanochlorin and a suite of sedimentary porphyrins of the bicycloalkanoporphyrin (bi-CAP) type.

Liquid chromatography/mass spectrometry with an atmospheric pressure chemical ionization interface permits the routine study of mixtures of algal-derived, chlorophyll transformation products isolated from biological and environmental samples. Interpretation of the mass spectra of standards of chlorophyll a and three of its commonly occurring transformation products has allowed the identification of components found in extracts from zooplankton faecal pellets and a marine surface sediment. This highly sensitive technique should prove valuable for pigment analysis in environmental studies.

The transformations undergone by chlorophyll a under anoxic conditions have been simulated by using the widespread marine prymnesiophyte Emiliania huxleyi as a substrate for a mixed bacterial community by incubation in a sediment slurry under sulphate reducing conditions. This resulted in the formation of pyrophaeophytin a after 77 days, along with smaller amounts of phaeophorbide a, pyrophaeophorbide a and mesopyrophaeophorbide a, from an original pigment distribution comprising mainly phaeophytin a, with a lower abundance of chlorophyll a. Mesopyrophaeophorbide a has not been reported previously as a product of any chlorophyll a defunctionalization study. Its formation under the conditions used suggests that the reduction of the C-3 vinyl substituent, required for transformation of chlorophyll a to a number of sedimentary porphyrins and chlorins, is a process which involves anaerobic bacterial communities.