Hydrocarbon-degrading bacteria in deep-water subarctic sediments (Faroe-Shetland Channel).

AIMS: The aim of this study was the baseline description of oil-degrading sediment bacteria along a depth transect in the Faroe-Shetland Channel (FSC) and the identification of biomarker taxa for the detection of oil contamination in FSC sediments. METHODS AND RESULTS: Oil-degrading sediment bacteria from 135, 500 and 1000 m were enriched in cultures with crude oil as the sole carbon source (at 12, 5 and 0°C respectively). The enriched communities were studied using culture-dependent and culture-independent (clone libraries) techniques. Isolated bacterial strains were tested for hydrocarbon degradation capability. Bacterial isolates included well-known oil-degrading taxa and several that are reported in that capacity for the first time (Sulfitobacter, Ahrensia, Belliella, Chryseobacterium). The orders Oceanospirillales and Alteromonadales dominated clone libraries in all stations but significant differences occurred at genus level particularly between the shallow and the deep, cold-water stations. Alcanivorax constituted 64% of clones at FSC135 but was absent at deeper stations. Pseudoalteromonas and Oleispira dominated the bacterial community at 500 and 1000 m. CONCLUSIONS: The genus Oleispira emerged as a major player in the early stages of crude oil degradation in deep-sea sediments of the FSC particularly at subzero temperatures. This finding is offering a direction for future research into biomonitoring tools for the detection of low levels of crude oil contamination in the deep FSC, and possibly high latitude cold waters in general. SIGNIFICANCE AND IMPACT OF THE STUDY: Oil and gas exploration in the FSC occurs at depths >1000 m but baseline environmental data necessary for the assessment of ecosystem recovery to prespill conditions in the event of an oil spill are lacking. This study will contribute to our ability to assess the impact of oil release in the FSC and guide the direction of bioremediation strategies tailored to the area.

kW-class direct diode laser for sheet metal cutting based on DWDM of pump modules by use of ultra-steep dielectric filters.

A direct diode laser was built with > 800 W output power at 940 nm to 980 nm. The radiation is coupled into a 100 µm fiber and the NA ex fiber is 0.17. The laser system is based on pump modules that are wavelength stabilized by VBGs. Dense and coarse wavelength multiplexing are realized with commercially available ultra-steep dielectric filters. The electro-optical efficiency is above 30%. Based on a detailed analysis of losses, an improved e-o-efficiency in the range of 40% to 45% is expected in the near future. System performance and reliability were demonstrated with sheet metal cutting tests on stainless steel with a thickness of 4.2 mm.

Magnetism and superconductivity driven by identical 4f states in a heavy-fermion metal.

The apparently inimical relationship between magnetism and superconductivity has come under increasing scrutiny in a wide range of material classes, where the free energy landscape conspires to bring them in close proximity to each other. Particularly enigmatic is the case when these phases microscopically interpenetrate, though the manner in which this can be accomplished remains to be fully comprehended. Here, we present combined measurements of elastic neutron scattering, magnetotransport, and heat capacity on a prototypical heavy fermion system, in which antiferromagnetism and superconductivity are observed. Monitoring the response of these states to the presence of the other, as well as to external thermal and magnetic perturbations, points to the possibility that they emerge from different parts of the Fermi surface. Therefore, a single 4f state could be both localized and itinerant, thus accounting for the coexistence of magnetism and superconductivity.

In situ experimental evidence of the fate of a phytodetritus pulse at the abyssal sea floor.

More than 50% of the Earth' s surface is sea floor below 3,000 m of water. Most of this major reservoir in the global carbon cycle and final repository for anthropogenic wastes is characterized by severe food limitation. Phytodetritus is the major food source for abyssal benthic communities, and a large fraction of the annual food load can arrive in pulses within a few days. Owing to logistical constraints, the available data concerning the fate of such a pulse are scattered and often contradictory, hampering global carbon modelling and anthropogenic impact assessments. We quantified (over a period of 2.5 to 23 days) the response of an abyssal benthic community to a phytodetritus pulse, on the basis of 11 in situ experiments. Here we report that, in contrast to previous hypotheses, the sediment community oxygen consumption doubled immediately, and that macrofauna were very important for initial carbon degradation. The retarded response of bacteria and Foraminifera, the restriction of microbial carbon degradation to the sediment surface, and the low total carbon turnover distinguish abyssal from continental-slope 'deep-sea' sediments.

The behavioural responses to 8-OH-DPAT, ipsapirone and the novel 5-HT1A receptor agonist Bay Vq 7813 in the pig.

In pigs, behavioural responses were examined after administration of 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT), a full agonist at 5-hydroxytryptamine (5-HT) receptors of the 5-HT1A subtype, and the pyrimidinylpiperazine derivatives ipsapirone and Bay Vq 7813 (2-[4-(2-pyrimidinyl)-1-piperazinylpropyl]-1,2-benzisothiazol++ +-3(2H) one-1,1-dioxide), which act as partial agonists at 5-HT1A receptors. The most prominent behavioural response examined after 8-OH-DPAT, 0.5 mg/kg i.m., ipsapirone, 2-5 mg/kg i.m., and Bay Vq 7813, 0.5-2 mg/kg i.m. or i.v., were head shakes. The potency of the three drugs to induce this behaviour correlated with their activity at 5-HT1A receptors as determined by inhibition of forskolin-stimulated adenylate cyclase, substantiating that the head shake response has potential as a quantitative probe of in vivo receptor function. The 5-HT2/5-HT1C receptor antagonist ritanserin did not counteract the head shakes induced by ipsapirone, suggesting that neither 5-HT2 nor 5-HT1C receptors are involved in mediation of this response to this 5-HT1A receptor agonist in pigs. Once daily administration of Bay Vq 7813 or ipsapirone for 3-5 days led to a reduction in the head shake response. 1-Pyrimidinylpiperazine (1-PP), a pharmacologically active metabolite shared by ipsapirone, Bay Vq 7813, and related pyrimidinylpiperazine derivatives, did not induce behavioural alterations in pigs. The data provide further evidence that marked species differences exist in functional responses to 5-HT receptor ligands.

Pharmacodynamic effects of serotonin (5-HT) receptor ligands in pigs: stimulation of 5-HT2 receptors induces malignant hyperthermia.

In pigs, the serotonin-2 (5-HT2) receptor agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), 0.8 mg/kg, induced "psychotic" behaviour (e.g., grimacing, backward locomotion, blank stare) and a muscular syndrome, which is known as malignant hyperthermia (MH) in pigs and humans. This syndrome is characterized by generalized skeletal muscle rigidity, leading to an increase in body temperature, marked acidosis, hyperkaliaemia, cyanosis and elevation of lactate, carbon dioxide and the muscle enzyme creatine kinase (CK) in plasma. In pigs which were selectively bred for susceptibility to MH induction by known triggering agents, such as halothane, the administration of DOI was fatal in 3 out of 5 animals. In genetically susceptible pigs, MH was also induced by 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT), 0.5-1.8 mg/kg, and D-lysergic acid diethylamide (LSD), 60-110 micrograms/kg. Furthermore, 5-MeO-DMT and LSD induced head shakes in the animals, which had not been observed after DOI and could not be blocked by 5-HT2-antagonists, ketanserin (0.5-5 mg/kg) and ritanserin (1-2.5 mg/kg). The psychotomimetic effects of 5-MeO-DMT could be blocked by ketanserin or ritanserin, which, depending on the dose, also reduced or totally prevented the hyperthermia and metabolic changes induced by 5-MeO-DMT in pigs. Administration of 5-MeO-DMT, 1.8 mg/kg, was fatal in 4 of 5 MH-susceptible pigs, whereas pigs injected with this dosage after pretreatment with ketanserin (0.5-5 mg/kg) or ritanserin (1-2.5 mg/kg) did not die. In pigs from MH-resistant littermates, administration of 5-MeO-DMT was not fatal. Comparison of metabolic changes in susceptible and non-susceptible pigs suggested that the marked increase in plasma potassium, which arises principally from damaged muscle cells, is primarily responsible for the fatal effect of DOI and 5-MeO-DMT in genetically susceptible individuals. In MH-susceptible pigs, which were anesthetized, relaxed and artificially ventilated, 5-MeO-DMT did not induce hyperthermia, thus substantiating that the marked hyperthermia observed in conscious pigs was a result of muscle activation and not due to effects on thermoregulation or blood pressure. The results indicate that hallucinogenic drugs with 5-HT2 agonistic effects trigger a life-threatening syndrome, MH, in genetically susceptible pigs. 5-HT2 antagonists, such as ketanserin or ritanserin, are capable of counteracting the fatality of this syndrome.

Sex differences in sensitivity to pentylenetetrazol but not in GABAA receptor binding.

Female rats have a higher threshold than males for seizures induced by the convulsant pentylenetetrazol, a GABAA receptor-chloride channel complex blocker. No sex difference was observed for the anticonvulsant activities of ethanol or diazepam to protect against pentylenetetrazol seizures. Ovariectomy reduces the pentylenetetrazol seizure threshold of females to that of males. In contrast, females have a lower threshold than males to electroshock seizures. Pentylenetetrazol receptors were compared in males and females and gonadectomized animals by binding of several radioligands to the GABAA receptor complex. No differences were found for these four groups of animals in the binding of [3H]flunitrazepam to the benzodiazepine sites and [35S]t-butyl bicyclophosphorothionate ([35S]TBPS) to the chloride channel/convulsant sites in membrane homogenates, nor for allosteric modulation of binding by GABA, the steroid anesthetic alphaxalone, or the benzodiazepine Ro 5-4864. In tissue section autoradiography, no difference was observed for these same assays nor for the binding of [3H]muscimol in the presence and absence of alphaxalone in several major regions. We conclude that circulating female sex hormones, possibly neurosteroid metabolites of progesterone, known to interact directly with the GABAA receptor complex, are involved in the sex differences in pentylenetetrazol seizure susceptibility.

The microbial community structure of different permeable sandy sediments characterized by the investigation of bacterial fatty acids and fluorescence in situ hybridization.

This study describes the microbial community structure of three sandy sediment stations that differed with respect to median grain size and permeability in the German Bight of the Southern North Sea. The microbial community was investigated using lipid biomarker analyses and fluorescence in situ hybridization. For further characterization we determined the stable carbon isotope composition of the biomarkers. Biomarkers identified belong to different bacterial groups such as members of the Cytophaga-Flavobacterium cluster and sulfate-reducing bacteria (SRB). To support these findings, investigations using different fluorescent in situ hybridization probes were performed, specifically targeting Cytophaga-Flavobacterium, gamma-Proteobacteria and different members of the SRB. Depth profiles of bacterial fatty acid relative abundances revealed elevated subsurface peaks for the fine sediment, whereas at the other sandy sediment stations the concentrations were less variable with depth. Although oxygen penetrates deeper into the coarser and more permeable sediments, the SRB biomarkers are similarly abundant, indicating suboxic to anoxic niches in these environments. We detected SRB in all sediment types as well as in the surface and at greater depth, which suggests that SRB play a more important role in oxygenated marine sediments than previously thought.

Self-selected walking speed in patients with hemiparesis after stroke.

"Self-selected walking speed" was measured in 18 patients with hemiparesis after stroke and compared with that in a healthy control group. The average speed of the patient group for a 30 m walk was 0.78 m/s (SD 0.24) and of the control group 1.69 m/s (SD 0.05). The intraindividual variation for the patients was 0.004 m/s and the interindividual variation 0.37 m/s. For the controls, the corresponding values were 0.000 m/s and 0.003 m/s, respectively. "Self-selected walking speed" correlated significantly with "functional walking test" (r = 0.91) and, "number of steps" (r=0.97) as well as with self-assessment scores of walking ability and stiffness, the degree of motor function of the lower extremities, muscle tone and balance. The significant correlation between "self-selected walking speed" and other studied tests strengthens their validity and implies that they can be used separately or in combination to evaluate the effect of rehabilitation programmes in patients with hemiparesis after stroke.

[Acral bullae following PUVA-therapy (author's transl)]. / Akrale Blasenbildung unter PUVA-Therapie.

Six patients with mycosis fungoides, psoriasis or generalized granuloma anulare developed acral bullae showing the clinical and histological picture of bullous pemphigoid during systemically applied PUVA-therapy. Immunohistological investigations (Protein A-Per-oxidase, Immunofluorescence) produced no proof of bullous pemphigoid.

Swallowing abnormalities in multiple sclerosis: correlation between videofluoroscopy and subjective symptoms.

The purpose of this study was to evaluate if subjective symptoms indicating an impaired deglutition correlate with videofluoroscopic findings in patients with multiple sclerosis (MS). Videofluoroscopic examinations of 18 MS patients were analyzed by a radiologist and a logopedist and compared with the symptoms of these patients. Four patients complained about permanent dysphagia. Six patients reported mild and intermittent difficulties in swallowing, but were asymptomatic at the time of videofluoroscopy. Eight patients had no symptoms regarding their deglutition. All patients ( n=4) who complained of permanent dysphagia showed aspiration. All patients ( n=6) with mild and intermittent difficulties in swallowing showed undercoating of the epiglottis and/or laryngeal penetration. Of those 8 patients without any swallowing symptoms, only 2 had a normal videofluoroscopy. Swallowing abnormalities seem to be much more frequent in patients with MS than generally believed and they may easily be missed clinically as long as the patients do not aspirate.

Regional variation in steroid anesthetic modulation of [35S]TBPS binding to gamma-aminobutyric acidA receptors in rat brain.

Steroids that enhance gamma-aminobutyric acid (GABA)A receptor function in the central nervous system allosterically modulate the binding of the convulsant chloride channel ligand [35S]-t-butyl bicyclophosphorothionate. When assayed in membrane homogenates and in tissue sections by autoradiography, concentration-dependence curves vary with respect to both brain region and the nature of the steroid. Alphaxalone and endogenous steroid hormone metabolites inhibit the binding of [35S]-t-butyl bicyclophosphorothionate in some regions, enhance it in others and give biphasic concentration-dependence in others, apparently the result of algebraic summation of two effects involving regional-dependent enhancement or inhibition. The alphaxalone effect is additive with that produced by adding GABA to the binding assays in some regions, but synergistic in other areas. Likewise, the effect of GABA is inhibited completely by saturating concentrations of the antagonist bicuculline methochloride in some areas but only partially in others, and completely or partially reversed by the convulsant benzodiazepine Ro5-4864, depending on region. The granule cell and molecular layers of cerebellum are particularly different in these allosteric interactions. The heterogeneity of binding behavior is consistent with the presence of multiple GABAA receptor subtypes in the brain. Regional variation in subunit gene expression apparently produces a family of hetero-oligomeric GABAA receptors with different biological and pharmacological properties, including qualitative and quantitative differences in modulation by neuroactive steroids.

A marine microbial consortium apparently mediating anaerobic oxidation of methane.

A large fraction of globally produced methane is converted to CO2 by anaerobic oxidation in marine sediments. Strong geochemical evidence for net methane consumption in anoxic sediments is based on methane profiles, radiotracer experiments and stable carbon isotope data. But the elusive microorganisms mediating this reaction have not yet been isolated, and the pathway of anaerobic oxidation of methane is insufficiently understood. Recent data suggest that certain archaea reverse the process of methanogenesis by interaction with sulphate-reducing bacteria. Here we provide microscopic evidence for a structured consortium of archaea and sulphate-reducing bacteria, which we identified by fluorescence in situ hybridization using specific 16S rRNA-targeted oligonucleotide probes. In this example of a structured archaeal-bacterial symbiosis, the archaea grow in dense aggregates of about 100 cells and are surrounded by sulphate-reducing bacteria. These aggregates were abundant in gas-hydrate-rich sediments with extremely high rates of methane-based sulphate reduction, and apparently mediate anaerobic oxidation of methane.

Routine screening for microdeletions by FISH in 77 patients suspected of having Prader-Willi or Angelman syndromes using YAC clone 273A2 (D15S10).

About 70% of patients with Prader-Willi syndrome (PWS) and Angelman syndrome (AS) have a common interstitial de novo microdeletion encompassing paternal (PWS) or maternal (AS) loci D15S9 to D15S12. Most of the non-deletion PWS patients and a small number of non-deletion AS patients have a maternal or paternal uniparental disomy (UPD) 15, respectively. Other chromosome 15 rearrangements and a few smaller atypical deletions, some of the latter being associated with an abnormal methylation pattern, are rarely found. Molecular and fluorescence in situ hybridization (FISH) analysis have both been used to diagnose PWS and AS. Here, we have evaluated, in a typical routine cytogenetic laboratory setting, the efficiency of a diagnostic strategy that starts with a FISH deletion assay using Alu-PCR (polymerase chain reaction)-amplified D15S10-positive yeast artificial chromosome (YAC) 273A2. We performed FISH in 77 patients suspected of having PWS (n = 66) or AS (n = 11) and compared the results with those from classical cytogenetics and wherever possible with those from DNA analysis. A FISH deletion was found in 16/66 patients from the PWS group and in 3/11 patients from the AS group. One example of a centromere 15 co-hybridization performed in order to exclude cryptic translocations or inversions is given. Of the PWS patients, 14 fulfilled Holm's criteria, but two did not. DNA analysis confirmed the common deletion in all patients screened by the D15S63 methylation test and in restriction fragment length polymorphism dosage blots. In 3/58 non-deletion patients, other chromosomal aberrations were found. Of the non-deleted group, 27 subjects (24 PWS, 3 AS) were tested molecularly, and three patients with an uniparental methylation pattern were found in the PWS group. The other 24/27 subjects had neither a FISH deletion nor uniparental methylation, but two had other cytogenetic aberrations. Given that cytogenetic analysis is indispensable in most patients, we find that the FISH deletion assay with YAC 273A2 is an efficient first step for stepwise diagnostic testing and mutation-type analysis of patients suspected of having PWS or AS.

Sporadic imprinting defects in Prader-Willi syndrome and Angelman syndrome: implications for imprint-switch models, genetic counseling, and prenatal diagnosis.

The Prader-Willi syndrome (PWS) and the Angelman syndrome (AS) are caused by the loss of function of imprinted genes in proximal 15q. In approximately 2%-4% of patients, this loss of function is due to an imprinting defect. In some cases, the imprinting defect is the result of a parental imprint-switch failure caused by a microdeletion of the imprinting center (IC). Here we describe the molecular analysis of 13 PWS patients and 17 AS patients who have an imprinting defect but no IC deletion. Heteroduplex and partial sequence analysis did not reveal any point mutations of the known IC elements, either. Interestingly, all of these patients represent sporadic cases, and some share the paternal (PWS) or the maternal (AS) 15q11-q13 haplotype with an unaffected sib. In each of five PWS patients informative for the grandparental origin of the incorrectly imprinted chromosome region and four cases described elsewhere, the maternally imprinted paternal chromosome region was inherited from the paternal grandmother. This suggests that the grandmaternal imprint was not erased in the father's germ line. In seven informative AS patients reported here and in three previously reported patients, the paternally imprinted maternal chromosome region was inherited from either the maternal grandfather or the maternal grandmother. The latter finding is not compatible with an imprint-switch failure, but it suggests that a paternal imprint developed either in the maternal germ line or postzygotically. We conclude (1) that the incorrect imprint in non-IC-deletion cases is the result of a spontaneous prezygotic or postzygotic error, (2) that these cases have a low recurrence risk, and (3) that the paternal imprint may be the default imprint.